Showing posts with label iptek. Show all posts
Showing posts with label iptek. Show all posts

Penyebab Nyamuk memilih calon korbannya

posted by : CarBari Thursday, August 27, 2009 0 comments

http://www.waspada.co.id/images/stories/juli2008/nyamuk.jpg

Apakah kamu ingin putus hubungan dengan nyamuk? Demikian bunyi sebuah iklan produk penolak nyamuk. Tetapi anda benar-benar bisa dijauhi oleh nyamuk, kalau anda mengetahui kenapa nyamuk menyukai anda dan menghindarinya seperti dijelaskan sebuah riset di bawah ini.

Ketika anda bersama-sama dengan sekelompok orang, anda mungkin sedikit heran kenapa ada yang digigit oleh nyamuk, sedangkan yang lain tidak. Jawaban adalah karena nyamuk memang memilih-milih calon korbannya untuk diisap darahnya, demikian kata para ahli. “Satu dari 10 orang sangat menarik bagi nyamuk,” demikian laporan Jerry Butler, PhD, profesor di Universitas Florida. Tetapi darahmu bukan sebagai makan malam bagi nyamuk. Nyamuk betina – pejantannya tidak mengisap menggigit orang – membutuhkan darah manusia untuk perkembangan telur-telurnya.

Siapa yang paling disukai nyamuk?

Para peneliti masih terus meneliti sebab-sebab nyamuk memilih bagian tertentu dari tubuh manusia untuk digigit. “Ada sejumlah penelitian yang sedang diselenggarakan pada berbagai bau-bauan yang terpancar dari tubuh manusia, yang kemungkinan menarik bagi nyamuk,” kata Joe Conlon, PhD, penasehat teknis kepada Asosiasi Kontrol Nyamuk Amerika. Dengan 400 campuran bahan berbeda untuk diuji, maka riset ini merupakan sebuah proses yang membutuhkan banyak tenaga. “Para peneliti baru mulai menembus permukaannya,” katanya.

Para ilmuwan memahami bahwa 85% unsur genetik menentukan kepekaan kita terhadap gigitan nyamuk. Nyamuk juga mengenali unsur-unsur kimiawi tertentu di tubuh kita, yang apabila ditemukan secara berlebihan di permukaan kulit, nyamuk-nyamuk segera berbondong-bondong mendekatinya.

“Manusia dengan jumlah konsentrasi steroid atau kolesterol yang tinggi di permukaan kulit akan menarik bagi nyamuk,” kata Butler kepada WebMD. “Itu bukan berarti kalau nyamuk akan menyerbu orang dengan tingkat kolesterol dalam darah yang tinggi secara menyeluruh,” jelasnya lagi. “Hanya proses pengolahan kolesterol di dalam tubuh yang tidak efisien akan menghasilkan sisa-sisa proses yang menumpuk di permukaan kulit dalam jumlah yang banyak.”


Nyamuk juga menyerang manusia yang tubuhnya menghasilkan kelebihan asam-asam tertentu, seperti asam urat, demikian penjelasan ahli serangga John Edman, PhD, juru bicara untuk Entomological Society dari Amerika. Unsur ini dapat merangsang sensor pembau pada nyamuk, menggerakkan mereka untuk mendarat dan mencurigai calon korban-korbannya. Nyamuk dapat “mencium” bau makan malamnya dari jarak yang luar biasa, yakni 50 meter, jelas Edman.

Selain itu gas karbondioksida juga menarik bagi nyamuk, bahkan dari jarak yang jauh, demikian penjelasan Conlon. Nyamuk lebih menyukai orang dewasa dibanding anak-anak karena kecenderungan gas karbon dioksida yang dihasilkan lebih banyak. Wanita-wanita hamil juga beresiko lebih tinggi, karena sebab yang sama. Gerakan dan suhu panas tubuh juga menarik bagi nyamuk.

Oleh sebab itu, jika anda ingin menghindari serangan gencar nyamuk pada malam hari, hindari kegiatan yang menimbulkan banyak gerakan, nafas terengah-engah sehingga menghembuskan banyak gas karbon dioksida, dan jangan berkeringat karena asam laktat dalam keringat merupakan daya tarik kuat bagi nyamuk untuk menggigit anda.

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Hmm… sepertinya banyak juga ya penggemar kiamat 2012. Ada apa sebenarnya, sehingga manusia sangat tertarik dan percaya dengan mudah pada isu-isu seperti ini?

Katanya, dunia akan berakhir pada tanggal 21 Desember 2012! Runutan angka yang menarik yang membuat Anda langsung terperangah dan menggumam, “Ah benar juga… pasti bener nih beritanya”. Lantas, tanpa telaah lanjut, Anda pun berkata kiamat tinggal 3 tahun lagi. Atau kalau Anda tak percaya teori kiamat, Anda langsung berkomentar, “Cuma Tuhan yang tahu kapan kiamat”, “Ah kamu musyrik…”, atau “Itu info disebarkan oleh orang tak beragama”. Sekali lagi, semua informasi hanya ditelan tanpa ditelaah.


Piramida peninggalan suku Maya.

Nah, karena dunia akan kiamat sebentar lagi, berhentilah merencanakan hidup, karier Anda, tak usah lagi berpikir untuk punya rumah, segeralah menikah sebelum kiamat, dan pastikan Anda bisa bersenang-senang menikmati hidup sebelum kiamat. Atau, segeralah bertobat. Jangan sampai saat kiamat Anda malah belum bertobat. Tiga tahun lagi lho!.

Kata sebagian orang, mungkin ini pembahasan yang aneh. Hampir setiap saat kita mendengar tentang berbagai teori kiamat… dan kenyataannya kita masih ada di sini. Belum ada satu teori pun yang kebenarannya terbukti. Tapi, kenapa 2012 begitu penting?

Katanya, kalender Maya akan berhenti tahun 2012, dan kemudian jadi semacam agama dan kepercayaan baru, mengalahkan kepercayaan yang ada di masyarakat. Mengabaikan semua alasan saintifik dan pada akhirnya membawa masyarakat pada kekhawatiran baru. Lupakan Nostradamus, Y2k, dan semua prediksi kiamat lainnya, karena sekali lagi menurut ramalan 2012, planet X akan kembali dan menghancurkan Bumi.

Ok… kita berhenti dulu di sini dan mari kita telaah setiap alasan yang muncul tentang kiamat 2012 ini. Dan bagi Anda para penggemar nubuat Kalender Maya, saya punya berita buruk untuk Anda semua. Tidak akan ada kiamat di tahun 2012… dan ini alasannya, silakan disimak.


Kalender Maya

Apa itu kalender Maya? Ini merupakan kalender yang disusun oleh sebuah peradaban yang dikenal dengan nama Maya pada kisaran 250-900 M. Bukti kehadiran peradaban Suku Maya ini bisa dilihat dari sisa kerajaannya di hampir semua bagian selatan Meksiko, Guatemala, Belize, El Savador, dan sebagian Honduras.

Dari bukti-bukti sejarah, masyarakat suku Maya memang memiliki kemampuan menulis yang baik dan juga kemampuan untuk membangun kota dan perencanaan kota. Dalam hal membangun, Suku Maya terkenal dengan bangunan piramida dan berbagai bangunan besar lainnya. Tak hanya itu, dalam kebudayaan, peradaban suku Maya memberi pengaruh yang sangat besar pada kebudayaan Amerika Tengah. Pengaruh itu bukan hanya dalam hal peradaban namun juga dalam hal populasi pribumi di area tersebut. Sampai saat ini, sejumlah Suku Maya masih tetap ada dan meneruskan tradisi mereka yang telah berumur ribuan tahun itu.

Suku Maya dalam kehidupannya menggunakan beberapa kalender berbeda. Bagi mereka, waktu merupakan penghubung dengan lingkaran spiritual. Kalender memang digunakan untuk hal-hal praktis seperti untuk kehidupan sosial, pertanian, perdagangan dan berbagai keperluan administratif. Namun dipercaya ada elemen religi yang besar di dalamnya yang memberi pengaruh. Bagi suku Maya, setiap hari memiliki ruh pelindung yang berbeda sehingga setiap hari memiliki fungsi yang berbeda pula. Sangat berbeda dengan kehidupan modern dengan kalender Gregorian yang hanya menetapkan kalender sebagai waktu yang terkait dengan hal-hal administratif, kehidupan sosial dan keperluan ekonomi.

Kebanyakan kalender Maya memiliki rentang waktu pendek.

* Kalender Tzolk’in berakhir dalam 260 hari
* Kalender Haab’ memberi perkiraan 1 tahun Matahari yakni 365 hari.

Suku Maya kemudian menggabungkan kedua kalender ini membentuk “Calendar Round”, siklus yang akan berakhir setelah 52 Haab (sekitar 52 tahun atau kisaran panjangnya satu generasi). Di dalam “Calendar round” terdapat Trecena ( siklus 13 hari) dan Veintena (siklus 20 hari). Tampaknya, sistem siklus ini berlaku dengan mempertimbangkan jumlah hari dalam 52 tahun adalah 18980 hari.

Untuk bangsa Maya, sains dan agama adalah satu. Mereka membangun sistem matematika dan astronomi yang cukup impresif, terkait dengan kepercayaan mereka. Pencapaian dalam hal matematika bisa dilihat pada notasi posisi dan penggunaan angka nol. Dalam astronomi, mereka secara akurat menghitung tahun Matahari, melakukan kompilasi tabel posisi bulan dan Venus, serta memprediksi Gerhana Matahari. Suku Maya juga memiliki penanggalan untuk “siklus Venus” yang cukup akurat. Kalender Venus ini dibuat berdasarkan lokasi Venus di langit malam. Hal yang sama tampaknya juga dilakukan pada planet-planet lainnya.

Sistem “Calendar Round” ini memang sangat baik untuk mengingat hari kelahiran atau periode keagamaan. Namun, untuk merekam sejarah, kalender ini tak bisa dijadikan patokan karena tak dapat merekam kejadian yang lebih tua dari 52 tahun.


Akhir Perhitungan Panjang = Akhir Dunia?

Alam semesta menurut suku Maya

Karena tak bisa merekam kejadian sejarah yang lebih tua dari 52 tahun, Suku Maya punya solusi lain. Dengan metode yang cukup inovatif, mereka bisa memperluas jangkauan “Calendar Round” yang tadinya cuma 52 tahun itu.

Sampai di titik ini, kalender Maya akan tampak sangat kuno, bahkan bisa dikatakan dibuat hanya berdasarkan kepercayaan religi, siklus bulan, kalkulasi matematika dengan siklus atau unit 13 dan 20 sebagai dasar perhitungan disertai campuran kepercayaan mitologi. Satu-satunya prinsip kalender yang memiliki korelasi dengan kalender modern hanyalah Haab yang mengenali panjang tahun Matahari yakni 365 hari. Sebagai jawaban atas penanggalan yang lebih panjang, Suku Maya membuat sistem penanggalan “Long Count” atau “Perhitungan Panjang”, kalender yang akan berakhir setelah 5126 tahun.

Sistem penanggalan Maya untuk “Long Count” ini memang menarik, dan secara numerik dapat diprediksi dan bisa dengan akurat menunjuk pada penanggalan dalam sejarah. Penanggalan ini bergantung pada basik perhitungan dengan unit 20. Kalender modern saat ini menggunakan dasar perhitungan dengan unit 10.

Nah bagaimana perhitungannya?

Tahun dalam “Long Count” kalender Maya, dimulai dari 0.0.0.0.0. Tiap angka 0 merepresentasikan angka 0-19, dan setiap angka merepresentasikan perhitungan hari-hari suku Maya.

Untuk hari pertama, kalendernya akan seperti ini : 0.0.0.0.1 dan pada hari ke-19 akan menjadi 0.0.0.0.19. Jika mencapai angka 20, kalendernya akan jadi : 0.0.0.1.0. Perhitungan ini akan menunjukkan 0.0.1.0.0 untuk satu tahun dan 0.1.0.0.0 untuk kisaran 20 tahun dan 1.0.0.0.0 utuk kisaran 400 tahun. Maka, penanggalan 2.10.12.7.1 akan melambangkan penanggalan untuk hari ke-1 di bulan ke-7 dan tahun 1012.

Lantas, apa hubungannya dengan akhir dunia?

Suku Maya sangat terobsesi dengan waktu. Pemahaman dan prediksi berbagai siklus waktu akan memberi mereka kemampuan untuk mengadaptasinya dalam kehidupan di dunia. Menurut kosmologi bangsa Maya, dunia ini telah diciptakan 5 kali dan dihancurkan 4 kali. Dalam skala yang sementara, berbagai hari di dalam satu tahun dianggap cocok untuk aktivitas tertentu, sedangkan sebagian lainnya merupakan ketidakberuntungan.

Nah, menurut kepercayaan suku Maya, sesuatu yang buruk akan terjadi jika kalender “Long Count” berakhir. Berbagai pembagian dilakukan para ahli, namun karena suku Maya mendasarkan perhitungan numerik pada siklus 13 dan 20, maka bisa jadi hari terakhir kalender mereka adalah 13.0.0.0.0. Kapankah itu? Angka 13.0.0.0.0 merepresentasikan 5126 tahun dan “Long Count” ini berawal pada 0.0.0.0.0 yakni 11 Agustus 3114 SM menurut penanggalan Gregorian.

Nah, dengan demikian, kalender Maya akan berakhir 5126 tahun kemudian, yakni 21 Desember 2012. Inilah yang jadi dasar pemikiran tentang kiamat di tahun 2012.


Akhir Dunia

Ilustrasi tabrakan yang terjadi

Sepertinya, saat sesuatu itu berakhir, termasuk ketika perhitungan kalender kuno berakhir, masyarakat cenderung berpikir pada kemungkinan ekstrem bahwa peradaban juga akan ikut berakhir. Entah dengan cara apa dunia akan berakhir. Berbagai argumentasi bermunculan, antara lain Bumi akan ditabrak oleh sebuah planet, asteroid, atau entah bencana apalagi. Intinya, jika kalender ini berakhir maka Bumi akan tersapu dan hancur.

Ahli arkeologi dan juga orang-orang yang keahliannya pada hal mitologi percaya bahwa akan ada era pencerahan yang muncul jika 13.0.0.0.0 tiba. Dan ini juga tidak berarti akan kiamat atau apa pun. Tidak ada bukti yang menunjukkan dunia akan berakhir. Bahkan, jika memang ada, maka suku Maya bisa dikatakan berhasil memprediksikan sebuah keajaiban religius.

Mitos terus berkembang, bahkan film Indiana Jones and the Kingdom of Crystal Skull sepertinya dibuat berdasarkan mitos suku Maya. Dikatakan, 13 tengkorak kristal akan dapat menyelamatkan kemanusiaan dari kiamat. Mitos di film ini mengatakan jika ke-13 tengkorak kuno ini tidak diletakkan bersama pada waktu tertentu, Bumi akan bergeser dari sumbunya. Menarik memang untuk sebuah film, bisa meraih penontonnya yang mudah percaya pada mitos.

Tak hanya itu. Mitos yang berkembang mengatakan bahwa Bumi akan dihancurkan oleh tabrakan Planet X, tabrakan meteorit, dihisap lubang hitam, dibunuh oleh flare Matahari, Bumi hancur oleh ledakan sinar gamma dari sistem bintang, datangnya zaman es yang lebih cepat dan pergeseran kutub magnet. Bahkan setiap prediksi disertai bukti-buktinya sendiri. Dan pada akhirnya begitu banyak pengikut kiamat 2012 ini. Sayangnya tak satu pun argumentasi yang diberikan itu bisa dibuktikan kebenarannya.

Fakta yang ada menyatakan Nubuat Kiamat Suku Maya murni berdasarkan kalender yang memang tidak didesain untuk menghitung penanggalan setelah 2012. Hal ini disebabkan karena suku Maya mendasarkan perhitungan pada siklus 13 dan 20.

Arkeo-astronom Maya bahkan masih memperdebatkan masalah kalender “Long Count” ini. Pertanyaannya, apakah kalender ini akan kembali ke 0.0.0.0.0 setelah 13.0.0.0.0 atau akan terus berlanjut sampai 20.0.0.0.0 (sekitar 8000M) dan kemudian kembali ke 0.0.0.0.0?

Mengutip kata-kata Karl Kruszelnicki dalam "Great Moments in Science" :

“ … ketika Kalender mengakhiri siklusnya, ia akan berputar kembali ke siklus berikutnya. Dalam masyarakat modern, setiap tanggal 31 Desember tidak diakhiri dengan akhir dunia, namun dilanjutkan oleh siklus berikut yakni 1 Januari. Karena itu, 13.0.0.0.0 dalam kalender Maya akan diikuti oleh 0.0.0.0.1 atau 22 desember 2012, yang hanya menyisakan beberapa hari untuk berbelanja keperluan Natal.”

Siklus kalender Maya boleh berakhir, namun siklus baru akan kembali berulang… dan membawa hari baru bagi penghuni Bumi.

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posted by : CarBari Saturday, March 29, 2008 0 comments

A sound level indicator of the Sonicu system hangs from the ceiling of the neonatal intensive care unit at Riley Hospital for Children in Indianapolis, Wednesday, March 19, 2008. The unit measures noise and displays a visual representation of measured sound levels. As decibels rise, the colors change from green to yellow to red, hushing chatty parents or doctors so the babies get the rest they need to develop. (AP Photo/Michael Conroy)
AP Photo: A sound level indicator of the Sonicu system hangs from the ceiling of the neonatal...

INDIANAPOLIS - Warning lights hover over the snoozing patients in Riley Hospital for Children's neonatal intensive care unit, ready to flash whenever sound levels creep beyond normal conversation.


As decibels rise, the colors on the new monitoring system change from green to yellow to red, hushing chatty parents or doctors so the babies get the rest they need to develop.

Noise louder than roughly the level of conversation can cause premature or sick babies' hearts to beat too fast or too slowly, said Dr. William Engle, a neonatologist at Riley. And interfering with babies' vital signs or sleep can slow development and healing because their bodies do most of that work while they sleep.

"The function of babies is to grow and develop, and in between they eat," he said.

Preemies also need quiet so they can learn their mother's voice and their brains can figure out how to process sound, things that normally happen in the last trimester before birth.

"It's definitely a great idea," Dr. Bob White, a neonatologist at South Bend's Memorial Hospital, said of the monitoring system in Riley's neonatal intensive care unit, or NICU.

White, who is not involved in creating or distributing the system, helped write national noise standards for NICUs that have been adopted by the American Institute of Architects and are used in most hospital design.

Inventor Chris Smith hopes doctors around the country agree with White. He has sold his Sonicu system to several Indiana hospitals and wants to expand nationally.

Smith, 43, had no training as a sound engineer and no plans to become an entrepreneur when his son Sean was born five weeks premature in 2000. But he noticed Sean flinch in response to bright light in the NICU of St. Vincent Indianapolis Hospital, and he wound up designing a system to soften the unit's lighting.

Then the nurses asked him what he could do about sound.

"That's really when I realized that there was no good way out there to measure sound, other than your standard, hand-held meter," he said.

Babies born too soon lose the muffling effect of the womb before their ears can filter sound, White said.

"The sounds ... come from all different directions and all different sources, and they're often associated with unpleasant sensations for the baby," White said.

NICUs are rife with noise pollution created by employees, equipment and excited family members.

"There's no good way for the nurses or doctors to walk up to a parent, tap them on the shoulder and say, 'You're being too loud,'" Smith said. "That's confrontational."

The former car mechanic filled hours of spare time in the evenings and on weekends researching sound standards and building a system.

Smith, who tinkered in radio and TV electronics in high school, hired an acoustical engineer to help. They created a ceiling-mounted system of microphones that picked up sound and funneled data back to a large control panel.

"There was a lot of wiring, a lot of labor, a lot of programming," he said.

St. Vincent paid around $100,000 for the system, which it installed about five years ago. Smith had no interest in shopping his invention to other hospitals because the work took so much time.

Then Riley Hospital, also in Indianapolis, called a few months later.

"They basically said, 'I want that,'" he said.

The latest version of Sonicu can feed a stream of both sound and light data digitally to a computer. It offers the cone-shaped warning lights and can quickly dim the lighting in a room that gets too noisy. It also can make lighting mimic the sun by brightening toward noon and then fading, which also helps babies sleep well.

White, the neonatologist who helped write the national standards, said he knows of no other NICU monitoring system that sophisticated.

Smith has sold systems to a handful of Indiana hospitals, so far to good reviews. He said the systems can cost anywhere from $40,000 to $400,000, depending on each hospital's needs.

The monitors have taught hospital staff to limit the number of groups making rounds at the same time because having more than one group in a room raises noise levels dramatically.

Most NICUs are filled with noise that can't be helped, White said. Fans in the heating and ventilation system have to operate almost constantly, and the monitors need to beep.

The Sonicu system reins in the main noise maker that can be controlled.

"People think, 'Oh gosh, I didn't realize, I'll go over here so I won't have to talk so loud,'" White said. "It really is something that addresses the human factors that we do have some control over."

Google's YouTube announced a tool, called YouTube Insight, but it doesn't seem all that great. The company says it can "give a lot of context around the performance of video over time, where are your audience coming from, and how your message is connecting to your audience." It's gotten a ton of coverage from the media.

But while the information you get is interesting, it's so broad that it strikes me as underwhelming. I tried it out on the most popular video I ever uploaded -- popular, I should add, for reasons that are unfathomable to me. Its title is "Loudest Car at CES," and I posted it from the Consumer Electronics Show in January 2007. It has since had 46,833 views.

The Insight tool shows me that it first broke 100 views a day on May 19, 2007 -- five months after the video was posted. I can follow a timeline and see that it passed 300 views a day on October 26, and even now gets nearly 200 views a day. I can also see that almost every viewer comes from the U.S.

I can see some other geographic oddities -- like, on Oct. 30, it was a very popular video in Namibia! (Like...huh??)

But that's about it. That's all I get from Insight. No idea why this video got popular when it did or where. I suppose a band might be able to find out that its music videos are extremely popular in some far-flung nation, and could make decisions to market or tour there. I'm sure there are other ways this is useful to marketers and potential YouTube advertisers. But hopefully YouTube will eventually give us more refined ways to slice and dice this stuff.

posted by : CarBari 0 comments






Visible Erosion of Antarctica’s Wilkins Ice Shelf


Seriously concerning information was made public this week, as researchers in the United States, Britain and Taiwan released images of large blocks of ice shearing away from the shelf along the West Antarctic Peninsula.

”In 1993, we predicted that this was going to be a vulnerable ice shelf,” Professor David Vaughan of the British Antarctic Survey recently said about the Wilkins Ice Shelf. ”But we got the time scales completely wrong. We were saying 30 years at that time, and now it's happened within 15.” The first proof of this prediction was recorded in February, when a 26-mile-long iceberg broke away from the ice mass.

Since it started being monitored, the shelf has lost three percent of its total extent. Unfortunately, this is just the beginning. The rest of the Wilkins Ice Shelf is kept in place by a narrow portion of thin ice and things aren’t looking up.

"Climate warming in the Antarctic Peninsula has pushed the limit of viability for ice shelves further south – setting some of them that used to be stable on a course of retreat and eventual loss. The Wilkins breakout won't have any effect on sea-level because it is floating already, but it is another indication of the impact that climate change is having on the region," said Vaughan.

Scientists all over the world are monitoring these sensitive areas with the use of satellites and on-site studies, gathering data on snowfall, ice loss, air and water temperatures, populations of animals and others.

The breakout is the latest drama in a region of Antarctica that has experienced unprecedented warming over the last 50 years. Several ice shelves have retreated in the past 30 years - six of them collapsing completely (Prince Gustav Channel, Larsen Inlet, Larsen A, Larsen B, Wordie, Muller and the Jones Ice Shelf.)

However, no immediate solution for global warming, which is considered to be the cause of these ice breaks, was found. The effort must be done globally and the major industial players must become fully aware of the very delicate state Earth’s vulnerable environment is in and take action.

posted by : CarBari 0 comments


In this combo photo the Sydney Opera House is illuminated by lights, top, and then shown with the lights switched off on Saturday, March 29, 2008, in Sydney, Australia. Australia's largest city will kick off a global dimming when it turns off its lights Saturday night for one hour in an effort to combat climate change. Sydney is the first of more than 370 cities and towns in more than 35 countries from Fiji to Ireland to Canada to take part in Earth Hour, organizers said. (AP Photo/Mark Baker)


SYDNEY, Australia (AP) — Sydney's iconic Opera House and Harbour Bridge went dark Saturday night as the world's first major city turned off its lights for this year's Earth Hour, a global campaign to raise awareness of climate change.

A lightning show was the brightest part of Sydney's skyline during Earth Hour, which began at 8 p.m. when the lights were turned off at the city's landmarks. Most businesses and homes were already dark as Sydney residents embraced their second annual Earth Hour with candlelight dinners, beach bonfires and even a green-powered outdoor movie.

"This provides an extraordinary symbol and an indication that we can be part of the solution" to global warming, Australian Environment Minister Peter Garrett told Sky News television, standing across the harbor from the dark silhouette of the Opera House.

Garrett said government offices and national monuments around the country participated in Earth Hour.

"We're not only talking the talk, we're walking the walk," he said as the hour ended. "Whatever your view is about the magnitude of the problem ... we can save money by using energy wisely and efficiently, and that gives us the added bonus of reduced greenhouse gas emissions."

During the one-hour event, Sydney was noticeably darker, though it was not a complete blackout. The business district was mostly dark; organizers said 250 of the 350 commercial buildings there had pledged to shut off their lights completely, and 94 of the top 100 companies on the Australian stock exchange were also participating.

The number of participants was not immediately available but organizers were hoping to beat last year's debut, when 2.2 million people and more than 2,000 businesses shut off lights and appliances, resulting in a 10.2 percent reduction in carbon emissions during that hour.

"I'm putting my neck on the line but my hope is that we top 100 million people," Earth Hour Australia chief executive Greg Bourne said.

The effect of last year's Earth Hour was infectious. This year 26 major world cities and more than 300 other cities and towns have signed up to participate.

New Zealand and Fiji kicked off the event this year. In Christchurch, New Zealand, more than 100 businesses and thousands of homes were plunged into darkness, computers and televisions were switched off and dinners delayed for the hour from 8 to 9 p.m. Suva, Fiji, in the same time zone, also turned off its lights.

Auckland's Langham Hotel switched from electric lights to candles as it joined the effort to reduce the use of electricity, which when generated creates greenhouse gases that contribute to global warming.

Australians had their own unique ways to mark the blackout as the clock struck 8 across the nation; one bar was offering free beers to customers who arrived with a black balloon to signify their carbon footprint; staff at beach bar donned solar-powered caps; a bed and breakfast offered candlelight cooking lessons; a children's hospital hosted a pajama party for its patients.

Following Australia, lights will go out in major Asian cities including Manila and Bangkok before moving to Europe and North America as the clock ticks on. One of the last major cities to participate will be San Francisco — home to the soon-to-be dimmed Golden Gate Bridge.

Organizers see the event as a way to encourage the world to conserve energy. While all lights in participating cities are unlikely to be cut, it is the symbolic darkening of monuments, businesses and individual homes they are most eagerly anticipating.

Even popular search engine Google put its support behind Earth Hour, with a completely black page and the words: "We've turned the lights out. Now it's your turn."

"Earth Hour is a call to action," Sydney's Lord Mayor Clover Moore said at the official launch ceremony. "People have now responded and it's time to introduce some significant long-term changes."

Australians have embraced Earth Hour and other environmental initiatives. The nation of around 21 million people is ranked as the world's worst greenhouse gas emitter per capita, largely because of its heavy reliance on coal-fired power stations. New Prime Minister Kevin Rudd has made the environment one of his priorities, signing the Kyoto Protocol on fighting global warming soon after taking office late last year.

"This approach reveals that, using existing imaging techniques, we can identify the molecular properties of tumors," said Michael Kuo, M.D., assistant professor of interventional radiology at UCSD School of Medicine. Kuo and colleagues analyzed more than 2,000 genes that had previously been shown to have altered expression in Glioblastoma multiforme (GBM) tumors. They then mapped the correlations between gene expression and MRI features.

The researchers also identified characteristic imaging features associated with overall survival of patients with GBM, the most common and lethal type of primary brain tumor.

The researchers discovered five distinct MRI features that were significantly linked with particular gene expression patterns. For example, one specific characteristic seen in some images is associated with proliferation of the tumor, and another with growth and formation of new blood vessels within the tumor--both of which are susceptible to treatment with specific drugs.

These physiological changes seen in the images are caused by genetic programs, or patterns of gene activation within the tumor cells. Some of these programs are tightly associated with drug targets, so when they are detected, they could indicate which patients would respond to a particular anti-cancer therapy, according to the researchers.

"For the first time, we have shown that the activity of specific molecular programs in these tumors can be determined based on MRI scans alone," said Kuo. "We were also able to link the MRI with a group of genes that appear to be involved in tumor cell invasion--a phenotype associated with a reduced rate of patient survival."

Laboratory work that relies on tissue samples is routinely used to diagnose and guide treatment for GBM. However, the biological activity shown may depend on the portion of the tumor from which the tissue sample is obtained. The researchers have shown that MRI could be used to identify differences in gene expression programs within the same tumor.

"Gene expression results in the production of proteins, which largely determine a tumor's characteristics and behavior. This non-invasive MRI method could, for example, detect which part of a tumor expresses genes related to blood vessel formation and growth or tumor cell invasion," said Kuo. "Understanding the genetic activity could prove to be a very strong predictor of survival in patients, and help explain why some patients have better outcomes than others."

Kuo also led an earlier study, published in Nature Biotechnology in May 2007, correlating CT images of cancerous tissue with gene expression patterns in liver tumors. "In the new study, we were able to take a different imaging technology, MRI, and apply it to a totally different tumor type," he said, noting that the studies open up promising new avenues for non-invasive diagnoses and classification of cancer.


Illustration of brain tumor scan. (Credit: Image courtesy of University of California - San Diego)

The new study will be published online by the Proceedings of the National Academy of Science the week of March 24.

Contributors to the paper include first author Maximilian Diehn, UCSD Department of Radiology and Department of Radiation Oncology at Stanford University School of Medicine; Christine Nardini and David S. Wang, UCSD Department of Radiology; Susan McGovern and Kenneth Aldape, Department of Neuropathology, University of Texas M.D. Anderson Cancer Center, Houston; Mahesh Jayaraman, Department of Radiology, Brown University; Yu Liang, UCSF Brain Tumor Research Center, and Soonmee Cha, Department of Radiology, UCSF Medical Center.

The research was funded in part by the National Institutes of Health.

Adapted from materials provided by University of California - San Diego.


In a major step toward solving the puzzle of schizophrenia, researchers have found that deletions and duplications of DNA are more common in people with the mental disorder, and that many of those errors occur in genes related to brain development and neurological function. (Credit: iStockphoto/Kiyoshi Takahase Segundo)

Schizophrenia, a debilitating psychiatric disorder, affects approximately 1 percent of the population. People with schizophrenia suffer from hallucinations, delusions, and disorganized thinking, and are at risk for unusual or bizarre behaviors. The illness greatly impacts social and occupational functioning and has enormous public health costs.

The team of investigators, led by Tom Walsh, Jon McClellan, and Mary-Claire King at the UW, and Shane McCarthy and Jonathan Sebat at Cold Spring Harbor, examined whether the genetic errors, which are individually rare DNA deletions and duplications, contribute to the development of schizophrenia. The findings, which were replicated by a team at the National Institute of Mental Health, appear in the March 27 online edition of the journal Science.

Some deletions and duplications are common and found in all humans. The researchers studied such mutations that were found only in individuals with the illness, and compared them to mutations found only in healthy persons. They theorized that rare mutations found only in schizophrenic patients would be more likely to disrupt genes related to brain functioning and thus may cause schizophrenia.

The study was conducted using DNA from 150 people with schizophrenia and 268 healthy individuals. The investigators found rare deletions and duplications of genes present in 15 percent of those with schizophrenia, versus only 5 percent in the healthy controls. The rate was even higher in patients whose schizophrenia first presented at a younger age, with 20 percent of those patients having a rare mutation.

The results were replicated by a second research team, led by Anjene Addington and Judith Rapoport at the National Institutes of Mental Health. They found a higher rate of rare duplications or deletions in patients whose schizophrenia began before age 12 years, a very rare and severe form of the disorder.

In individuals with schizophrenia, mutations were more likely to disrupt signaling genes that help organize brain development. Each mutation was different, and impacted different genes. However, several of the disrupted genes function in related neurobiological pathways.

The findings suggest that schizophrenia is caused by many different mutations in many different genes, with each mutation leading to a disruption in key pathways important to a developing brain. Once a disease-causing mutation is identified, other different disease-causing mutations may be found in the same gene in different people with the illness.

Thus, for most cases of schizophrenia, the genetic causes may be different. This observation has important implications for schizophrenia research. Currently, most genetic studies examine for mutations that are shared among different individuals with the illness. These approaches will not work if most patients have different mutations causing their condition.

Fortunately, there are now genomic technologies available that allow researchers to discover rare mutations within each individual with a disorder. As these technologies improve, it will be possible to detect other types of disease-causing mutations. Eventually, the identification of genes disrupted in individuals with schizophrenia will allow the development of new treatments more specifically targeted to disrupted pathways.

The research team included many other scientists at a variety of institutions, including Evan Eichler and his colleagues at the University of Washington, and investigators at the State University of New York at Stony Brook, Case Medical Center in Cleveland, the University of North Carolina, the University of California Los Angeles, the National Cancer Institute, and the National Institute on Aging.

This work was supported by many different grants from several foundations and agencies, including the Forrest C. and Frances H. Lattner Foundation, NARSAD, the Simons Foundation, the Stanley Medical Research Foundation, the Howard Hughes Medical Institute, the National Institute on Aging, the National Institute of Mental Health, and the Mental Health Division of the Washington State Department of Social and Health Services.

Adapted from materials provided by University of Washington.


Red-eyed Tree Frog. 43 percent of known amphibian species in the world are at risk because of a fungus. (Credit: iStockphoto/Mark Kostich)

The research, led by SIUC zoologist Karen R. Lips, and SIUC zoologist Michael W. Sears, underscores the dire circumstances facing up to 43 percent of known amphibian species in the world and points up the need for more regulations, conservation efforts and quarantines to prevent the fungus’ spread.

An associate professor of zoology in the College of Science at SIUC, Lips is at the forefront of in research in catastrophic decline of frog species brought on by the Batrachochytrium dendrobatidis fungus. The fungus, known to researchers as “Bd,” wipes out frog populations essentially by completely blocking their skin. Amphibians such as frogs depend on their skin to provide oxygen and moisture. Bd infections cause electrolyte imbalance, which can lead to cardiac arrest.

Lips has studied the issue since the early 1990s, becoming a recognized expert on the subject. She, along with her graduate and doctoral students, regularly visit the high jungles of Central America, roughing it in the wild while collecting data on the ecological systems before, during and after the fungus arrives.

This latest study, conducted with Sears, an assistant professor of zoology at SIUC, and two other colleagues at the Illinois Natural History Survey and Zoo Atlanta, expands upon that work by seeking better understanding of the spread of the fungus, its triggers and how it might be spread.

Specifically, the researchers examined data from South American amphibian declines to see whether the wave-like spread seen in Central America, typical of an emerging infectious disease, was evident.

One previous theory, for instance, blamed the fungus on global climate change. Lips and Sears, however, found climate change doesn’t appear to trigger outbreaks of the fungus, but that it instead spreads in wave-like patterns often seen in exotic species and emerging infectious diseases. They call their theory the “spreading pathogen hypothesis.”

Using modeling, the researchers found evidence of four different introductions of Bd into South America. They found that the fungus spread through the population at a rate similar to that seen in Central America and in a manner that best explains amphibian population declines in Central and South America.

“What makes the study really relevant is we can now generalize how the fungus is spread,” Lips said. “We know from our research, that if we start looking in the right time and place in an area where the fungus is, we’re probably going to see it affecting frog populations. This helps us understand what’s going on, and it can potentially help us get out in front of it.”

The study could help governments and environmental agencies focus on ways to prevent the fungus’ spread through more regulation of potential infection routes, such as the ornamental plant and aquarium wildlife trade. The fungus can easily hitch a ride to other regions through such trade, Lips said.

“If you go and buy an ornamental plant from one of these regions and plant it in your yard, or you buy a frog at a pet shop, think about it. If the fungus is there and still alive, it’s now introduced into the environment. Then it can get into your pond or streams.”

Lips said simple testing of such products and organisms before importing them could reveal the fungus’ presence. Once discovered, simple anti-fungal drugs will kill the fungus before it can contaminate an area.

“Our research has shown that once the fungus gets somewhere new it spreads like wildfire,” Lips said. “So the key is preventing it from spreading.”

The fungus is present in North America, including Illinois, but little is known so far about its impact here. With funding from the Illinois Department Natural Resources, Lips in the coming months will survey the extent of the fungus and its impact in Illinois.

Among the study’s key points:

  • Climate change, while having some negative impacts on amphibian biodiversity, does not appear to have triggered the disease in Central America and the Andes of South America, as suggested by previous studies.
  • The fungus appears to have spread in a wave-like manner, in a typical pattern of disease spread.
  • The fungus was introduced in South America in the late 1970s or early 1980s. After introduction, the disease spread along the Andes, infecting native amphibians and often causing the extinction of entire populations and species.
  • There is robust evidence supporting the “spreading pathogen hypothesis,” which holds the disease was and continues to be spread in a wave-like pattern seen in Central America. It is likely this same pattern will emerge in other places where Bd has been detected, including North America and Europe.

Lips said the study increases understanding of the disease, which should allow humans to take steps to limit its spread.

“We need to get into areas ahead of the spreading wave — such as eastern Panama and the southern Andes — to conduct intensive surveys and monitoring for both native amphibians and the … fungus,” Lips said. Environmental agencies also should immediately begin conservation programs aimed at conserving rare and endangered amphibian species that might be wiped out by the fungus.

“At this time, the fungus cannot be controlled or managed in wild amphibians nor their habitats,” Sears added.

The island of Madagascar, which is home to a large number of plants and animals found nowhere else in the world, so far appears free of the deadly fungus. The researchers said governments should take steps to maintain that status.

In the future, Lips believes that researchers should study treatment options for wild amphibians and possibly their habitats to prevent or minimize the fungus while establishing a global network of disease surveillance. They should increase communication and monitoring of global trade and increase outreach communication with researchers and policy makers to raise awareness on its potential impacts in other geographic locations.

Researchers also should survey museum specimens to better determine the location, timing and possible sources of the fungus and its introduction into the environment in various locations. They also should study fungus samples for genetic clues as to its origins and the different strains involved.

This research was published March 25 in the journal PLoS Biology.

Adapted from materials provided by Southern Illinois University Carbondale, via Newswise.


A novel strategy based on targeted immune suppression using human umbilical cord blood cells may improve the pathology and cognitive decline associated with Alzheimer's disease. (Credit: iStockphoto/Joseph Jean Rolland Dub�)

Following a series of low-dose infusions of human umbilical cord blood cells into mice with Alzheimer's-like disease, the amount of amyloid-ß and ß-amyloid plaques--hallmarks of Alzheimer's pathology in the brain--was markedly reduced. Amyloid-ß induces an inflammatory response in the brain associated with the interaction of CD40 and CD40L, two pro-inflammatory molecules.

Human umbilical cord blood cell therapy was associated with suppression of CD40-CD40L activity, suggesting that this therapeutic approach modulates the activity of the immune system, offering the potential to target the pathogenic inflammatory response that may contribute to a variety of degenerative conditions, including Alzheimer's disease.

Jun Tan, PhD, MD, and colleagues from USF (Tampa), Yale University (New Haven, CT), Cedars-Sinai Medical Center (Los Angeles, CA), Saneron CCEL Therapeutics (Tampa, FL), and Saitama Medical School (Japan), concluded that human umbilical cord blood cell-induced disruption of the CD40-CD40L interaction may alleviate the key pathologic changes in the brain associated with Alzheimer's disease in a report entitled, "Peripherally administered human umbilical cord blood cells reduce parenchymal and vascular beta-amyloid deposits in Alzheimer mice."

Dr. Tan, Robert A. Silver Chair, Rashid Laboratory for Developmental Neurobiology at Silver Child Development Center, University of South Florida Department of Psychiatry, said “Our study is the first to report that the potential therapeutic mechanism of umbilical cord blood cells is more through targeting and fixing this malevolent peripheral immune functioning rather than through direct interaction with neurons. We believe restoring the balance between molecules that promote and inhibit inflammation could play a big role in future treatment strategies against Alzheimer’s disease.”

"Previously, challenging observations have reported phenomena suggesting the non-hematologic therapeutic potential of blood stem cells. What is novel about this paper is its application to Alzheimer's disease, and a significant advance in characterizing the ameliorative mechanism of action" says Graham C. Parker, PhD, Editor-in-Chief of Stem Cells and Development, and a research professor in The Carman and Ann Adams Department of Pediatrics, Wayne State University School of Medicine, Children's Hospital of Michigan.

Journal reference: Peripherally Administered Human Umbilical Cord Blood Cells Reduce Parenchymal and Vascular β-Amyloid Deposits in Alzheimer Mice. Stem Cells and Development. doi:10.1089/scd.2008.0018

Adapted from materials provided by Mary Ann Liebert, Inc./Genetic Engineering News, via EurekAlert!, a service of AAAS.


This scanning electron micrograph depicts numerous clumps of methicillin-resistant Staphylococcus aureus bacteria, commonly referred to by the acronym, MRSA; Magnified 2381x. (Credit: Janice Haney Carr, CDC)

Dr. Ferric Fang, UW professor of laboratory medicine and microbiology, and his UW colleagues Dr. Anthony Richardson and Dr. Stephen Libby set out to determine what makes Staph aureus a better pathogen than other bacteria. They focused on a chemical compound called nitric oxide (NO), a natural antibiotic that our cells excrete to protect us from pathogens. For most bacteria, NO creates an environment that keeps invading microbes from undergoing respiration or fermentation, vital chemical processes that allow bacteria to grow.

The researchers found that Staph aureus has a mechanism that allows it to produce lactic acid in the presence of NO, which allows it to maintain its chemical balance and keep growing and thriving in the harsh host environment. When Staph aureus is exposed to NO, it produces the novel enzyme responsible for lactic acid production, along with another enzyme that converts NO to non-toxic products. NO is commonly found in the nose and nasal passages, and is meant to protect people against disease-causing microbes. But Staph aureus is commonly found in the nose despite the presence of NO, the researchers explained.

When the researchers modified Staph aureus to take away its ability to make lactic acid, the bacteria could no longer tolerate NO. The modified bacteria also lost their ability to survive in host immune cells and cause lethal disease in mice.

"MRSA has become an enormous public health problem, by causing both hospital- and community-acquired infections," explained Fang. "Staph aureus has already colonized about one-third of the world's population, so traditional antibiotics will probably not be the complete answer to the MRSA problem."

However, the researchers added, trying to make Staph aureus more susceptible to our natural defenses might lead to new strategies to de-colonize the population and prevent staphylococcal infections.

Adapted from materials provided by University of Washington, via EurekAlert!, a service of AAAS.


(Credit: University of Pittsburgh, PET Amyloid Imaging Group)

Until now, the beta-amyloid deposits to which PiB binds have been confirmed, without question, only in the autopsied brains of patients afflicted with Alzheimer's. The new findings, which correlate PiB-identified beta-amyloid deposits from living patients to their post-mortem autopsy results, will ultimately aid in the early diagnosis of Alzheimer's, help clinicians monitor the progression of the disease and further the development of potential treatments.

"This is final confirmation of what we have believed all along -- that Pittsburgh Compound-B allows us to accurately assess the amount of beta-amyloid plaques in brains of people afflicted with Alzheimer's," said senior author Steven DeKosky, M.D., professor of neurology, psychiatry, neurobiology and human genetics and director of the Alzheimer's Disease Research Center at the University of Pittsburgh.

Invented and developed by Pitt researchers Chester Mathis, Ph.D., professor of radiology and pharmaceutical sciences, and William Klunk, M.D., Ph.D., professor of psychiatry and neurology, PiB is a radioactive compound that, when coupled with positron emission tomography (PET) imaging, can be injected into the bloodstream to enable researchers to visualize the brains of people with the memory-stealing illness and see the location and distribution of the beta-amyloid plaque deposits associated with Alzheimer's. The distinguishing factor between Alzheimer's disease and other dementias is the presence of these amyloid plaques, which are thought to kill brain cells.

In the study, a 63-year-old woman with a clinical diagnosis of Alzheimer's underwent PiB PET imaging. The PET scan showed significant retention of PiB in distinct regions of her brain. Upon her death 10 months later, her autopsied brain was analyzed using histological and biochemical assays to detect a variety of amyloid deposits, including the beta-amyloid plaques. The regions of her brain where the PET scans had identified the highest PiB levels before death correlated precisely with the regions of high beta-amyloid plaque concentrations in her autopsied brain.

Beta-amyloid plaques, the hallmark of Alzheimer's disease, are just one type of amyloid structure that can be found in diseased brains. However, other forms of amyloid are not thought to be specific for Alzheimer's, or they have significantly different roles in the pathogenesis of this disease. To further validate the binding properties of PiB to beta-amyloid and the presence of Alzheimer's disease, sophisticated laboratory studies were performed on the autopsied brains of 27 other patients with confirmed Alzheimer's disease.

"In every subject, and with each test that we performed, our results supported the idea that PiB binds almost exclusively to beta-amyloid, which means that we can, with confidence, look to PiB to indicate the troublesome beta-amyloid deposits in brains of living patients," said the lead author Milos Ikonomovic, M.D., assistant professor of neurology and psychiatry at the University of Pittsburgh.

"This patient who selflessly and generously agreed to PiB PET scanning and who gave us the gift of her brain has enabled us to compare what we detected during her life to what we confirmed after her death. The findings from our study of her brain, coupled with the further confirmation of the other 27 brains, tell us without a doubt that PiB binds to beta-amyloid and that it is a reliable indicator of the presence of Alzheimer's disease in those who are suffering its cruel effects," said Dr. Klunk.

"This work is an important step forward in the development of new tools for both research and clinical care," noted Neil Buckholtz, Ph.D., chief of the Dementias of Aging Branch of the National Institute on Aging, National Institutes of Health, which supported the study. "It provides additional evidence validating the use of PiB to identify beta-amyloid deposits in living individuals and advancing the potential use of PiB as an outcome measure in clinical trials of anti-beta-amyloid therapeutics."

It is estimated that up to 4.5 million people in the United States have Alzheimer's, including 50 percent of those older than age 85 and 10 percent of those over age 65. The number of those affected is expected to triple over the next 50 years.

Journal reference: Post-mortem correlates of in vivo PiB-PET amyloid imaging in a typical case of Alzheimer's disease. Brain. Advance Access published online on March 12, 2008 Brain, doi:10.1093/brain/awn016

In addition to Drs. DeKosky, Ikonomovic, Klunk and Mathis, the research team included Eric Abrahamson, Ph.D., Julie Price, Ph.D., Nicholas Tsopelas, M.D., Brian Lopresti, B.S., Scott Ziolko, B.S., Wenzhu Bi, B.S., William Paljug, M.Sc., Manik Debnath, M.S., Caroline Hope, M.Sc., Barbara Isanski, M.Sc., and Ronald Hamilton, M.D., all of the University of Pittsburgh School of Medicine.

The study was supported by grants from the National Institutes of Health, the Alzheimer's Association, The U.S. Department of Energy and the Dana Foundation.

Adapted from materials provided by University of Pittsburgh Schools of the Health Sciences.


No sidewalk and no green buffer makes walking feel unsafe. A wide treed buffer between a sidewalk and the street encourages walking. (Credit: Image courtesy of University of Michigan)

It's not necessarily because they're spoiled, lazy or over scheduled. According to a University of Michigan researcher, concerns about safety are the main reason that less than 13 percent of U.S. children walked or biked to school in 2004, compared to more than 50 percent who did so in 1969.

"These concerns are strongly linked to the kind of physical environment children navigate between home and school," said Byoung-Suk Kweon, an environmental and landscape architecture researcher at the U-M Institute for Social Research (ISR).

"The greener the route, the more likely it is that children will walk and bike."

Using Geographic Information System (GIS) data combined with a survey of 186 parents of 5th through 8th grade students, Kweon found that parents were most concerned about the speed and volume of traffic students would encounter en route to school; the possibility of crime; and the weather.

"In Texas, where we lived when I conducted this study, our sons did not walk to school because we lived too far away," said Kweon, who is also affiliated with the U-M School of Natural Resources and Environment. In general, she found, children who walk to school usually live less than three-quarters of a mile away.

"In Ann Arbor, they do walk to school. We have a 27 degree rule. If it's colder than that, we drive them; if it's warmer than that, they walk."

In her study, Kweon found that children use sidewalks, not bike lanes, when they ride to school. "Parents may be concerned about the safety of bike lanes, and they may be telling their children to ride on the sidewalk because it's safer," she said. "We may need to re-think how to place bike lanes in school walk zones."

To learn more about how the physical environment influences parents' perceptions of safety and their willingness to allow their children walk or bike to school, Kweon and colleagues conducted a series of laboratory-based simulation studies, testing six different pedestrian environments.

"It's very important for parents that there be a separation or buffer between traffic and the sidewalk," she said. "They are much more willing to let their children walk when this buffer is at least eight feet wide, and when there are also trees in this area." Trees not only provide shade, but also serve as a sort of vertical barrier between sidewalk and street.

Although improving the physical environment reduces parents' concerns for their children's safety, Kweon found that the social environment—especially the likelihood of crime—strongly affects parental perceptions of safety as well. Kweon hopes to conduct a related study in Detroit to examine how the intersection of social and physical factors influences the likelihood that children will walk to school.

By identifying environmental elements conducive to walking and biking to school, Kweon hopes her research may help improve children's physical health and reduce the incidence of childhood obesity, especially prevalent among minority children.

"Walking or biking to school helps children develop an early habit of engaging in physical activity, and that can lead to a healthier and more active and healthier population," she said.

Kweon's study was supported by a grant from the U.S. Department of Transportation and from the Southwest Region University Transportation Center in College Station, Texas.

Adapted from materials provided by University of Michigan


A natural antioxidant found in grape skins and red wine can help destroy pancreatic cancer cells. (Credit: iStockphoto)

The new study also showed that when the pancreatic cancer cells were doubly assaulted -- pre-treated with the antioxidant, resveratrol, and irradiated -- the combination induced a type of cell death called apoptosis, an important goal of cancer therapy.

The research has many implications for patients, said lead author Paul Okunieff, M.D., chief of Radiation Oncology at the James P. Wilmot Cancer Center at the University of Rochester Medical Center. The study is published in the March edition of the journal, Advances in Experimental Medicine and Biology.

Although red wine consumption during chemotherapy or radiation treatment has not been well studied, it is not "contraindicated," Okunieff said. In other words, if a patient already drinks red wine moderately, most physicians would not tell the patient to give it up during treatment. Perhaps a better choice, Okunieff said, would be to drink as much red or purple grape juice as desired.

Yet despite widespread interest in antioxidants, some physicians are concerned antioxidants might end up protecting tumors. Okunieff's study showed there is little evidence to support that fear. In fact, the research suggests resveratrol not only reaches its intended target, injuring the nexus of malignant cells, but at the same time protects normal tissue from the harmful effects of radiation.

"Antioxidant research is very active and very seductive right now," Okunieff said. "The challenge lies in finding the right concentration and how it works inside the cell. In this case, we've discovered an important part of that equation. Resveratrol seems to have a therapeutic gain by making tumor cells more sensitive to radiation and making normal tissue less sensitive."

Resveratrol is known for its ability to protect plants from bacteria and fungi. Purified versions have been described in scientific journals as potential anti-cancer, anti-inflammatory and anti-atherogenic agents, and for their ability to modulate cell growth. Other well-known antioxidants derived from natural sources include caffeine, melatonin, flavonoids, polyphenols, and vitamins C and E.

A flurry of antioxidant studies in recent years has not proven how and why they work at the cellular level. At the suggestion of a young scientist in his lab, Okunieff began studying resveratrol as a tumor sensitizer. That's when they discovered its link to the mitochondria.

The discovery is critical because, like the cell nucleus, the mitochondria contains its own DNA and has the ability to continuously supply the cell with energy when functioning properly. Stopping the energy flow theoretically stops the cancer.

Researchers divided pancreatic cancer cells into two groups: cells treated without resveratrol, or with resveratrol, at a relatively high dose of 50 mg/ml, in combination with ionizing radiation. (The resveratrol concentration in red wine can be as high as 30 mg/ml, the study said, and higher doses are expected to be safe as long as a physician is monitoring.)

They evaluated the mitochondria function of the cells treated with resveratrol, and also measured apoptosis (cell death), the level of reactive oxygen species in the cells, and how the cell membranes responded to the antioxidant.

Laboratory experiments showed that resveratrol:

  • Reduced the function of proteins in the pancreatic cancer cell membranes that are responsible for pumping chemotherapy out of the cell, making the cells chemo-sensitive.
  • Triggered the production of reactive oxygen species (ROS), which are substances circulating in the human body that have been implicated in a number of diseases: when ROS is increased, cells burn out and die.
  • Caused apoptosis, which is likely the result of increased ROS.
  • Depolarized the mitochondrial membranes, which indicates a decrease in the cell's potential to function. Radiation alone does not injure the mitochondrial membrane as much.

The team also wanted to investigate why pancreatic cancer cells seem to be particularly resistant to chemotherapy. The pancreas, a gland located deep in the abdomen, produces insulin and regulates sugar, and pumps or channels powerful digestive enzymes into the duodenum. This natural pumping process, however, ends up ridding the needed chemotherapy from cells in the pancreas. But just as reseveratrol interferes with the cancer cells' energy source, it also may decrease the power available to pump chemotherapy out of the cell.

"While additional studies are needed," Okunieff said, "this research indicates that resveratrol has a promising future as part of the treatment for cancer."

In the same journal, Okunieff and his group also reviewed why resveratrol protects normal tissue, and found that antioxidants can be designed to take advantage of certain biochemical properties or cellular targets, making them more effective.

The National Institute of Allergy and Infectious Diseases funded the research through a URMC program called the Center for Medical Countermeasures Against Radiation. Co-authors on the studies are: Weimin Sun, Wei Wang, Jung Kim, Peter Keng, Shanmin Yang, Hengshan Zheng, Chaomei Liu, Lurong Zhang, Jacqueline P. Williams, Steven Swarts and Amy K. Huser. All are from the Department of Radiation Oncology, University of Rochester Medical Center.

Adapted from materials provided by University of Rochester Medical Center, via EurekAlert!, a service of AAAS.


Composition of the nanodevice. (Credit: Wayne Frasch and David Spetzler)

Even more incredible than the device itself, is that it is based on the world's tiniest rotary motor: a biological engine measured on the order of molecules.

Frasch works with the enzyme F1-adenosine triphosphatase, better known as F1- ATPase. This enzyme, only 10 to 12 nanometers in diameter, has an axle that spins and produces torque. This tiny wonder is part of a complex of proteins key to creating energy in all living things, including photosynthesis in plants. F1-ATPase breaks down adenosine triphosphate (ATP) to adenosine diphospahte (ADP), releasing energy. Previous studies of its structure and characteristics have been the source of two Nobel Prizes awarded in 1979 and 1997.

It was through his own detailed study of the rotational mechanism of the F1-ATPase, which operates like a three-cylinder Mazda rotary motor, that Frasch conceived of a way to take this tiny biological powerhouse and couple it with science applications outside of the human body.

An article authored by Frasch and his colleagues in the ASU School of Life Sciences details the technology that would allow this. Their publication "Single-molecule detection of DNA via sequence-specific links between F1-ATPase motors and gold nanorod sensors" was recently published in the journal Lab on a Chip, and featured in the online journal Chemical Biology.

What Frasch and his colleagues show is that the enzyme can be armed with an optical probe (gold nanorod) and manipulated to emit a signal when it detects a single molecule of target DNA. This is achieved by anchoring a quiescent F1-ATPase motor to a surface. A single strand of a reference biotinylated DNA molecule is then attached to its axle. The marker protein, biotin, on the DNA is known to bind specifically and tightly to the glycoprotein avidin, so an avidin-coated gold nanorod is then added. The avidin-nanorod attaches to the biotinylated DNA strand and forms a stable complex.

When a test solution containing a target piece of DNA is added, this DNA binds to the single complementary reference strand attached to the F1-ATPase. The DNA complex, suspended between the nanorod and the axle, forms a stiff bridge. Once ATP is added to the test solution, the F1-ATPase axle spins, and with it, the attached (now double-stranded) DNA and nanorod. The whirling nano-sized device emits a pulsing red signal that can then be detected with a microscope.

According to Frasch, the rotation discriminates fully assembled nanodevices from nonspecifically bound nanorods, resulting in a sensitivity limit of one zeptomole (600 molecules). Simply put, if it's not moving and flashing, it simply isn't relevant.

Moreover, Frasch says, "Studies with the F1-ATPase in my laboratory show that since it can detect single DNA molecules, it far exceeds the detection limits of conventional PCR [polymerase chain reaction] technology."

Such a detection instrument based on the F1-ATPase enzyme would also be "faster and more portable," he adds.

With support from Science Foundation Arizona (SFAz), Frasch will transfer his work from the bench to biotech, through establishment of a local company that utilizes the nano-sized F1-ATPase to produce a DNA detection instrument.

A prototype of the DNA detector is already in development. It is roughly the size of a small tissue box. Sampling would be as simple as taking a swab from an infected wound or a piece of baggage, dissolving it in a solution and placing a drop on a slide bearing reference F1-ATPases and their nanorods. Once in the instrument, red blinking signals emitted by rotating nanorods would let a computer know there's trouble, literally, in a flash.

SFAz funding has also enabled Frasch to extend the method to do protein detection at the single molecule level. This is novel because, unlike DNA, proteins can not be amplified artificially to improve the chances of detection.

"Rapid and sensitive biosensing of nucleic acids and proteins is vital for the identification of pathogenic agents of biomedical and bioterrorist importance," notes Frasch, who is also with the Center for Bioenergy and Photosynthesis in the College of Liberal Arts and Sciences. "It also provides a new avenue through which to analyze genotypes and forensic evidence."

Adapted from materials provided by Arizona State University, via EurekAlert!, a service of AAAS.


Bitter melon. (Credit: Image courtesy of Garvan Institute of Medical Research)

Teams from the Garvan Institute of Medical Research and the Shanghai Institute of Materia Medica pulped roughly a tonne of fresh bitter melon and extracted four very promising bioactive components. These four compounds all appear to activate the enzyme AMPK, a protein well known for regulating fuel metabolism and enabling glucose uptake.

"We can now understand at a molecular level why bitter melon works as a treatment for diabetes," said Professor David James, Director of the Diabetes and Obesity Program at Garvan. "By isolating the compounds we believe to be therapeutic, we can investigate how they work together in our cells."

People with Type 2 diabetes have an impaired ability to convert the sugar in their blood into energy in their muscles. This is partly because they don't produce enough insulin, and partly because their fat and muscle cells don't use insulin effectively, a phenomenon known as 'insulin resistance'.

Exercise activates AMPK in muscle, which in turn mediates the movement of glucose transporters to the cell surface, a very important step in the uptake of glucose from the circulation into tissues in the body. This is a major reason that exercise is recommended as part of the normal treatment program for someone with Type 2 diabetes.

The four compounds isolated in bitter melon perform a very similar action to that of exercise, in that they activate AMPK.

Garvan scientists involved in the project, Drs Jiming Ye and Nigel Turner, both stress that while there are well known diabetes drugs on the market that also activate AMPK, they can have side effects.

"The advantage of bitter melon is that there are no known side effects," said Dr Ye. "Practitioners of Chinese medicine have used it for hundreds of years to good effect."

Garvan has a formal collaborative arrangement with the Shanghai Institute of Materia Medica. In addition to continuing to work together on the therapeutic potential of bitter melon, we will be exploring other Chinese medicines.

Professor Yang Ye, from the Shanghai Institute and a specialist in natural products chemistry, isolated the different fractions from bitter melon and identified the compounds of interest.

"Bitter melon was described as "bitter in taste, non-toxic, expelling evil heat, relieving fatigue and illuminating" in the famous Compendium of Materia Medica by Li Shizhen (1518-1593), one of the greatest physicians, pharmacologists and naturalists in China's history," said Professor Ye. "It is interesting, now that we have the technology, to analyse why it has been so effective."

"Some of the compounds we have identified are completely novel. We have elucidated the molecular structures of these compounds and will be working with our colleagues at Garvan to decipher their actions at a molecular level. We assume it's working through a novel pathway inside cells, and finding that pathway is going to be very interesting."

The results are published online March 27 in the international journal Chemistry & Biology.

Adapted from materials provided by Garvan Institute of Medical Research.


Scientists have identified key protein fragments in infectious diseases and are reporting a strategy that could usher in more effective vaccines. (Credit: Courtesy of Queensland Health)

Traditional vaccine development involves the use of microorganisms to trigger an immune response by the body. However, this approach can produce unwanted side effects and may be ineffective against microbes with extremely complex infection cycles. Therefore, researchers agree on the need for better vaccine.

In the study, Manuel E. Patarroyo and his son Manuel A. Patarroyo describe a completely new strategy for designing more effective vaccines, which are chemically synthesized in the laboratory without the use of microorganisms. They identified dozens of key protein fragments involved in the complex infection process of the malaria parasite, from which they designed, specifically modified and synthesized chemically some of the most promising malaria vaccine candidates that have been tested to date.

Likewise, identifying the disease-related protein fragments involved in the complex infection process of other transmittable diseases could result in new, more effective vaccines to help fight these diseases, the scientists say. They also note that this innovative approach establishes for the first time the emerging rules for the development of vaccines against diseases scourging humankind.

The study "Emerging Rules for Subunit-Based Multiantigenic, Multistage Chemically Synthesized Vaccines" appears in the current issue of ACS' Accounts of Chemical Research (http://dx.doi.org/10.1021/ar700120t)

Adapted from materials provided by American Chemical Society, via EurekAlert!, a service of AAAS.


2008.03.19 "Pi of the Sky" telescope detected the brightest ever optical outburst from a distant universe. The explosion happened 7.5 billion light years from the Earth, halfway across the visible Universe. The telescope is only 71 mm in diameter. (Credit: Image courtesy of Soltan Institute for Nuclear Studies)

[Editor's Note: Folks, some time ago we reported on Artlandia's sister product for Adobe Illustrator... now they sweep away the patterns field with Artlandia SymmetryShop for Photoshop! Click images for enlargements...

Artlandia SymmetryShop Pro Photoshop Patterns

spectacular patterns and textures come to Photoshop...

Artlandia, the originators of Artlandia SymmetryWorks, the ultimate pattern design plug-in for Adobe Illustrator, has released Artlandia SymmetryShop, a new plug-in that makes pattern design in Adobe Photoshop easy and fully automatic.

Floral Pattern

No more pattern tedium

Similar to its Illustrator counterpart, SymmetryShop relieves the designer from the tedium of manually creating repeat patterns, a painstaking task that involves thousands of precise geometric transformations that used to make interactive experimentation with patterns virtually impossible. Artlandia SymmetryWorks, which solved this problem in Adobe Illustrator, is now widely used for creating surface designs for wallpaper, fabrics, quilting, tilings, web pages, fine arts, and other applications.

Lilies pattern

Does in Photoshop what you had to do in Illustrator

With the release of the new plug-in, designers are no longer restricted to the use of Illustrator and can chose to create pattern designs in Photoshop, which has clear advantages for working with larger raster images, for example, sophisticated scanned hand-painted compositions or high-resolution photographs. As a tool for professional designers, SymmetryShop creates patterns of all seventeen symmetries and allows the designer to produce an even richer repertoire of popular repeat types with a single click. The built-in library includes drop, diamond, spot, grid, gradation, and scale repeats for the same broad range of applications. Once created, patterns can be instantly converted from one repeat type to another while pattern parameters can be interactively adjusted, either from within the plug-in or directly in Photoshop.

Artlandia

Unlimited creativity

The plug-in further allows for unlimited iterations and refinement, with the design process spanning multiple sessions, which is especially important in producing complex, real-life pattern designs. Going beyond patterns based on repeating a predefined geometric region of a source image, a technique that typically results in simplified or kaleidoscopic designs, SymmetryShop produces patterns from arbitrary selection, which brings about organic, interlocking patterns, with optionally smoothed-away boundaries. This makes the design process more natural and the designer more productive. The plug-in also gives the designer full control over the number of repeating tiles allowing the creation of border designs as well as surface patterns.

Artlandia Symmetry Shop for Photoshop SymmetryShop is compatible with all versions of Photoshop starting from 6 and later, including the latest releases of Photoshop CS2 (Photoshop 7 or later recommended). It is immediately available for Windows and Mac OS, see: http://www.artlandia.com.

Artlandia SymmetryShop

We'll be back later to show you some of the fantastic things you can do with Artlandia SymmetryShop... in the mean time, check out their site if you ever need to make patterns in Photoshop!

Artlandia Info
URL = www.artlandia.com
Topic = Image Processing: graphics, illustration, photography

Using a Layer Mask to merge two photos

Combining Pictures

This is one of the most frequent questions we get in the Photoshop Forums and Photoshop 911. Here's a fairly simple solution that will work in almost all versions of Photoshop after version 4, and in all versions of Photoshop Elements.

The first step is making sure our photos are compatible. We'll do this by opening both images, and selecting
STEPImage > Image Size
In this dialog, make sure the resolutions are the same, and make a mental note of which file has larger dimensions. You'll want to drag the smaller image into the larger one.

Combining images

STEPClick in the image to move, HOLD and DRAG that image into the larger file. It will arrive there on its own unique layer. Now you can close the moved file, you no longer need it.

Before moving further, take a quick, visual survey of the images and make any adjustments that may be necessary -- color adjustments, levels, sharpen, etc.

Set the Mask

In the first set of operations, we'll set a mask, and then use a radial gradient to open a nicely feathered "window" to allow parts of the overlay image to show through.

STEPOPEN DIAGRAM #2 NOW

Make your browser windows more narrow in order to read here, while seeing the diagram at the same time.

STEP#1 The Mask: Click the layer mask button at the bottom of the layers palette, (#1)

You'll see the Layer Mask appear (#2) and the double lines framing it will indicate it's selected. If not, then click on it to select it.

STEP#3 Gradient Tool: Tap "g" or select the Gradient tool from the Tool bar. Address the Options Bar at the top of your window, and make sure the second icon in "Gradient Styles" is clicked -- to make it a Radial Gradient.
In the Gradient Pop-Down arrow, make sure the gradient is Foreground to Background method -- and tap the letter D to reset your colors to Black over White; then tap X to set White over Black. White must be the foreground color.

STEP#4 Deploy the Gradient:
Click in your image at the point you want to show the MOST of the added photo -- and drag to the point where you want the photo to diminish.
Note, I've clicked (#4) just about the center between the faces because I want them to be revealed the most.

STEPNOW CONTINUE TO THE NEXT PROCESS . . .

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Who invented "Photoshop Tips & Tricks"

from the Editor:
I was delighted that day back in 1989 when Peggy Killburn called to ask if I could handle one more speaker in my "Great Graphics Tips & Tricks" session scheduled for the 1990 Macworld Expo. "Yes" was my response to her request to add Russell Brown to my panel. After all, we loved Adobe's young "Illustrator" program, and were quite anxious to try out their upcoming new product called "Photoshop." After seeing his demo, I was convinced Photoshop would be big. So the next month we added "Photoshop Tips & Tricks" to our regular DTG Magazine uploads to Compuserve, GEnie and AOL. The rest is history.
I only regret that I didn't trademark the name.

Fred Showker editor publisher

Editor / Publisher: Photoshop Tips & Tricks, DTG Magazine.

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