Mon, 07 Jul 2008 04:24:01 GMT

Everywhere I look

Remember the early days of this humble blog when I anguished about the lack of walnut trees in my woods at Roundrock? There was a point where any time I happened upon a walnut tree, it gave it a post of its own, keeping a count. I even tried plotting their location on a map once.

Okay, I’m older now, and I don’t have to be so stupid. It seems like just about everywhere I look though, I see the distinctive leaves of a walnut tree over my head. (Well, not really everywhere.) When Seth and I were stumbling about the north-facing slope on our last visit, tracking the interloping cattle, I happened to look up and see this walnut tree you see above. It obviously has been growing there for years, far longer than my tenure at Roundrock, yet this was the first time I had seen it.

So let’s say that my powers of observation are set pretty low. And let’s say that I probably have three times as many walnut trees in my woods as I have seen. That means I have a pretty good population of walnuts in the 80+ acres of Roundrock. I can say that I’ve seen them in nearly every part of my woods, so I think it is safe to say they are throughout.

What I haven’t seen is an actual walnut. I’m not sure why that is. Are my walnut trees not fertile? That doesn’t seem likely. They got here on their own, so it is probably that they are as vigorous and complete as any walnut tree anywhere. Are the squirrels getting all of the nuts before I can even glimpse them? Perhaps, but while we have seen squirrels in our woods, we haven’t see a lot of them. Surely one or two nuts have escape their notice long enuf for me to notice them. Or are my powers of observation set on low? Are there walnuts in the trees and I’m just not seeing them? Let’s say that.

Missouri calendar:

• Smoketrees bloom on southwestern Missouri glades.

Today in Missouri history:

• Rose O''Neill was born on this date in 1874. From her home near Springfield, Missouri she created Kewpie dolls in illustrations and figurines. In the Roaring Twenties these sweet elvish creatures became an international craze.

Posted by: Roundrockjournal      Read more     Source

June 25, 2008, 10:31 PM CT

Primate's Scent Speaks Volumes

Perhaps judging a man by his cologne isn't as superficial as it seems.

Duke University researchers, using sophisticated machinery to analyze hundreds of chemical components in a ringtailed lemur's distinctive scent, have observed that individual males are not only advertising their fitness for fatherhood, but also a bit about their family tree as well.

"We now know that there's information about genetic quality and relatedness in scent," said Christine Drea, a Duke associate professor of biological anthropology and biology. The male's scent can reflect his mixture of genes, and to which animals he's most closely related. "It's an honest indicator of individual quality that both sexes can recognize," she said.

Lemurs, distant primate cousins of ours who split from the family tree before the monkeys and apes parted ways, have a complex and elaborate scent language that until recently was completely undiscovered by humans. Drea said it's language that is undoubtedly richer than we can imagine.

"All lemurs make use of scent," she said. "The diversity of glands is just amazing".

Ringtailed males have scent glands on their genitals, shoulders and wrists, each of which makes different scents. Other lemur species also have glands on their heads, chests and hands. Add to these scents the signals that can be conveyed in feces and urine, and there's a lot of silent, cryptic communication going on in lemur society......... Posted by: Ashley      Read more         Source

May 15, 2008, 7:30 PM CT

Gravity-defying bird beak mystery

As Charles Darwin showed nearly 150 years ago, bird beaks are exquisitely adapted to the birds' feeding strategy. A team of MIT mathematicians and engineers has now explained exactly how some shorebirds use their long, thin beaks to defy gravity and transport food into their mouths.

The phalarope, commonly found in western North America, takes advantage of surface interactions between its beak and water droplets to propel bits of food from the tip of its long beak to its mouth, the research team reports in the May 16 issue of Science.

These surface interactions depend on the chemical properties of the liquid involved, so phalaropes and about 20 other birds species that use this mechanism are extremely sensitive to anything that contaminates the water surface, especially detergents or oil.

"Some species rely exclusively on this feeding mechanism, and so are extremely vulnerable to oil spills," said John Bush, MIT associate professor of applied mathematics and senior author of the paper.

Wildlife biologists have long noted the unusual feeding behavior of phalaropes, which spin in circles on the water, creating a vortex that sweeps small crustaceans up to the surface, just like tea leaves in a swirling tea cup.

The birds peck at the surface, picking up millimetric droplets of water with their prey trapped inside. Since the birds point their beaks downward during the feeding process, gravity must be overcome to get those droplets from the tip of the bird's long beak to its mouth. Until now, scientists have been puzzled as to how that happens......... Posted by: Ashley      Read more         Source

April 1, 2008, 8:58 PM CT

Some Migratory Birds Can't Find Success In Urban Areas

New research finds fresh evidence that urbanization in the United States threatens the populations of some species of migratory birds.

But the six-year study also refutes one of the most widely accepted explanations of why urban areas are so hostile to some kinds of birds.

Most ecologists have assumed that common nest predators in urban areas - such as house cats and raccoons - were destroying eggs or killing young birds in greater numbers than in rural areas, said Amanda Rodewald, co-author of the study and associate professor of wildlife ecology at Ohio State University's School of Environment and Natural Resources.

But this study was one of the first to actually test that assumption by monitoring natural nests over several years. And the results showed that predators weren't the main problem: instead, the birds just didn't seem to like urban areas and gave up more easily.

Urban areas attracted lower-quality birds which, in comparison to those in rural areas, arrived later in the spring, left earlier in the fall, made fewer nesting attempts and were much less likely to return to nesting spots from year to year.

"There is something about these urban forests that strikes the birds as unsuitable," Rodewald said. "Even when they try nesting, they are less likely to renest after failure or to return in subsequent years"......... Posted by: Ashley      Read more         Source

February 26, 2008, 5:19 PM CT

Giant Fossil Frog from Hell

A team of researchers, led by Stony Brook University paleontologist David Krause, has discovered the remains in Madagascar of what may be the largest frog ever to exist.

The 16-inch, 10-pound ancient frog, scientifically named Beelzebufo, or devil frog, links a group of frogs that lived 65 to 70 million years ago with frogs living today in South America.

Discovery of the voracious predatory fossil frog -- reported on-line this week in the journal Proceedings of the National Academy of Sciences (PNAS) -- is significant in that it may provide direct evidence of a one-time land connection between Madagascar, the largest island off Africa's southeast coast, and South America.

To identify Beelzebufo and determine its relationship to other frogs, Krause collaborated with fossil frog experts Susan Evans, lead author of the PNAS article, and Marc Jones of the University College London. The authors concluded that the new frog represents the first known occurrence of a fossil group in Madagascar with living representatives in South America.

"Beelzebufo appears to be a very close relative of a group of South American frogs known as 'ceratophyrines,' or 'pac-man' frogs, because of their immense mouths," said Krause, whose research was funded by the National Science Foundation (NSF). The ceratophryines are known to camouflage themselves in their surroundings, then ambush predators......... Posted by: William      Read more         Source

January 24, 2008, 11:00 PM CT

When accounting for the global nitrogen budget, don't forget fish

Like bank accounts, the nutrient cycles that influence the natural world are regulated by inputs and outputs. If a routine withdrawal is overlooked, balance sheets become inaccurate. Over time, overlooked deductions can undermine our ability to understand and manage ecological systems.

Recent research by the Universite de Montreal (Canada) and the Cary Institute of Ecosystem Studies (Millbrook, New York) has revealed an important, but seldom accounted for, withdrawal in the global nitrogen cycle: commercial fisheries. Results, published as the cover story in the recent issue of Nature Geoscience, highlight the role that fisheries play in removing nitrogen from coastal oceans.

Nitrogen is essential to plant and animal life; however, it is possible to have too much of a good thing. During the past century, a range of human activities have increased nitrogen inputs to coastal waters. Fertilizer run-off is the best documented and most significant source of terrestrial nitrogen pollution. Nitrogen-rich fertilizer applied to farmland eventually makes its way into coastal waters via a network of streams and rivers.

Research spearheaded by Roxane Maranger (Universite de Montreal) and Nina Caraco (Cary Institute) demonstrates that commercial fisheries play an important but declining role in removing terrestrial nitrogen from coastal waters. Accounting for this withdrawal is crucial; terrestrial-derived nitrogen can stimulate coastal phytoplankton growth, leading to eutrophication. Typically typically eutrophic waters are characterized by reduced dissolved oxygen, decreased biodiversity, and species composition shifts......... Posted by: Tyler      Read more         Source

Fri, 28 Dec 2007 14:31:09 GMT

Deadwood in winter

Sky and snowpack are two kinds of white, and the pale skin of arboreal fungi makes a third. Within a year or two after death, a log or snag has already become an extension of the ground in one respect: it is shot through with networks of fungal hyphae, the mycelium. This is not a root structure - remember that fungi are more closely related to animals than to plants. Rather, it is like a skilled miner who has adapted to the job so well that he has become almost indistinguishable from the ore.



Wood so mined becomes lighter than paper: punk wood. It breaks easily, but does not yet crumble between the fingers. It makes an excellent tinder, burning with a green flame.



Other miners of dead trees include ants and termites and the pale grubs of beetles: stag beetles, longhorn beetles, scarabs and more. Such xylophagous insects contribute at least as much to the decomposition of trees as the fungi - indeed, some species of the latter require the openings of the former before they can begin their own infiltrations.

Various species of bees and wasps and the maggots of flies, midges and mosquitoes also make their homes in the tunnels of beetle grubs, and feed on their dried-out excrement. Though there’s very little insect activity this time of year, a half-rotted snag preserves a record as visually rich and intriguing as a Dead Sea scroll. And of course the woodpeckers also come knocking, drilling doors into larder, shelter, and sounding board. The winter woods echoes with their stacatto taps and calls.



If after all this the dead still stand, it is often at odd angles. The sun is no longer of any interest to them. They alone try the embrace of other trees, and when the wind blows, they are vociferous in their complaint.
__________

Don’t forget to send tree-related links to Lorianne - zenmama at gmail dot com - by December 30 for inclusion on the next Festival of the Trees. And be sure to visit the Insecta issue of qarrtsiluni, which is still in progress with a number of posts yet to come. Posted by: Vianegativa      Read more     Source

Mon, 10 Dec 2007 04:20:37 GMT

Cavanillesia arborea

Inspired by the photographs of baobab a few weeks ago, Nikolaus von Behr sent along these photographs of the “Brazilian baobab”, or barriguda, from the country''s dry interior forests (map). Thank you, Nikolaus!

The Encyclopedia of Earth entry on Atlantic dry forests makes special mention of Cavanillesia arborea: “Dry forests are fairly dense, up to 25 to 30 meters (m) high and characterized by tree species such as Cavanillesia arborea, Cedrela fissilis, Schinopsis brasiliensis, Astronium urundeuva, Aspidosperma macrocarpa, and Tabebuia sp. The most remarkable tree is certainly Cavanillesia arborea, with a huge, bottle-shaped trunk that reaches its maximum diameter of 1.5 m or more about 3 m above ground level. It attains heights of about 27 meters.”. Like most forests of the world, this region is under pressure: “Approximately 70 percent of the native forest has largely been destroyed. Because these forests grow on relatively rich soils, they are prime candidates for clearing both irrigated and dry-field agriculture. Furthermore, the high biomass of these forests makes them important sources of fuel for Brazil''s steel and pig iron industries, which run entirely on charcoal. The most diverse dry forests on flat terrain and rich soil have been completely removed”.

The Smithsonian Institution''s Centres of Plant Diversity site also has a section dedicated to these forests: Caatinga of North-Eastern Brazil. It has an excellent description of the floristic elements of the region.

On a different topic, Eirik aka pannicle@Flickr relayed to me his photographs of banana flowers and fruits after seeing yesterday''s entry on the related Strelitzia nicolai. I thought I''d share the set with other folks who enjoy BPotD. In particular, check out this photograph of the developing fruit. Posted by: Daniel Mosquin      Read more     Source

December 6, 2007, 7:21 PM CT

Chemical triggers for aggression in mice

The work, reported in an advance, online issue of the journal Nature on December 6, 2007, furthers the broad and important goal of elucidating how the neurological system can detect and respond to specific cues in of a sea of potential triggers.

These results are a really exciting starting place for us to understand how pheromones and the brain can shape behavior, says team leader Lisa Stowers of the Scripps Research Department of Cell Biology.

Pheromones are chemical cues that are released into the air, secreted from glands, or excreted in urine and picked up by animals of the same species, initiating various social and reproductive behaviors.

Eventhough the pheromones identified in this research are not produced by humans, the regions of the brain that are tied to behavior are the same for mice and people, says James F. Battey, Jr., director of the National Institute on Deafness and Other Communication Disorders (NIDCD) of the National Institutes of Health, which provided funding for the study. Consequently, this research may one day contribute to our understanding of the neural pathways that play a role in human behavior. Much is known about how pheromones work in the insect world, but we know very little about how these chemicals can influence behavior in mammals and other vertebrates......... Posted by: Ashley      Read more         Source

December 5, 2007, 8:34 PM CT

'Flying Fish' unmanned aircraft takes off

Flying fish were the inspiration for an unmanned seaplane with a 7-foot wingspan developed at the University of Michigan. The autonomous craft is thought to bethe first seaplane that can initiate and perform its own takeoffs and landings on water.

Funded by the Department of Defense's Defense Advanced Research Projects Agency (DARPA), it is designed to advance the agency's "persistent ocean surveillance" program.

Engineering scientists from U-M recently returned from sea trials off the coast of Monterey, Calif., where they demonstrated the craft's capability to DARPA officials.

"The vehicle did very well," said Hans Van Sumeren, associate director of the U-M Marine Hydrodynamics Laboratories. "To take off and land in the water was a big effort. We did it 22 times."

The scientists named the robotic plane Flying Fish after its inspiration. Guy Meadows, director of the U-M Marine Hydrodynamics Laboratories, conceived of the design while out on the water. "I saw these fish pop up and soar over the waves," Meadows said.

That got Meadows and colleagues looking at sea birds for a design for their craft.

"We studied sea birds seriously," Meadows said. "They're all about the same size---about 20 pounds with a 2-meter wingspan. It turns out that, aerodynamically speaking, that's a sweet spot to be flying close to the water. Our plane is about the size of a large pelican."........ Posted by: Kevin      Read more         Source

December 3, 2007, 10:15 PM CT

Toll of climate change on world food supply

Global agriculture, already predicted to be stressed by climate change in coming decades, could go into steep, unanticipated declines in some regions due to complications that researchers have so far inadequately considered, say three new scientific reports. The authors say that progressive changes predicted to stem from 1- to 5-degree C temperature rises in coming decades fail to account for seasonal extremes of heat, drought or rain, multiplier effects of spreading diseases or weeds, and other ecological upsets. All are believed more likely in the future. Coauthored by leading scientists from Europe, North America and Australia, they appear in this weeks issue of the Proceedings of the National Academy of Sciences (PNAS).

A number of people assume that we will never have a problem with food production on a global scale. But there is a strong potential for negative surprises, said Francesco Tubiello, a physicist and agricultural expert at the NASA/Goddard Institute of Space Studies who coauthored all three papers. Goddard is a member of Columbia Universitys Earth Institute.

In order to keep pace with population growth, current production of grainfrom which humans derive two-thirds of their proteinwill probably have to double, to 4 billion tons a years before 2100. Studies in the past 10 years suggest that mounting levels of carbon dioxide in the airthought to bethe basis of human-caused climate changemay initially bolster the photosynthetic rate of a number of plants, and, along with new farming techniques, possibly add to some crop yields. Between now and mid-century, higher temperatures in northerly latitudes will probably also expand lands available for farming, and bring longer growing seasons. However, these gains likely will be canceled by agricultural declines in the tropics, where even modest 1- to 2-degree rises are expected to evaporate rainfall and push staple crops over their survival thresholds. Existing research estimates that developing countries may lose 135 million hectares (334 million acres) of prime farm land in the next 50 years. After mid-century, continuing temperature rises5 degrees C or more by then--are expected to start adversely affecting northern crops as well, tipping the whole world into a danger zone......... Posted by: Tyler      Read more         Source

Tue, 20 Nov 2007 01:48:08 GMT

Sunday sampling

Some sort of mushroom, I think. We saw this baseball-sized fungus growing on the ridgetop at Fallen Timbers on our last visit. It bloomed from the recent rains, I suppose. On first glancing at it, I really thought it was a baseball that had found its way to the middle of the forest somehow.

Deer hunting season began in Missouri yesterday and continues for ten days. Actually, it is high-powered firearm deer hunting season that began yesterday. There are all sorts of other hunting seasons through the fall and winter for taking deer: archery, muzzleloading, special local hunts, seasons for disabled hunters. The high-powered firearm season is the time when I stay out of the forest though.

Sometimes I imagine that hunting season is merely a conspiracy by the deer to keep me out of the woods so I don’t see them having parties and doing all sorts of anthropomorphic things like sitting in my comfy chair under the shady tarp overlooking the empty lake. I’m too afraid of going out to the woods to check on my suspicions, though.

The next Festival of the Trees returns to Missouri when Larry Aryers of Hannibal’s Riverside Reflections hosts. This is the second time around for Larry. Send your links to Larry at larry (dot) ayers (at) gmail (dot) com by November 29 with “Festival of the Trees” in the subject line. Or you can use the handy online submission form at Blog Carnival. Remember, your submission does not have to be a post you have made on your own blog. If you come across any kind of link that speaks of trees, you can submit it if you think it is worthy.

The Festival has been growing for more than a year now, just as anything to do with trees should. Most of the credit goes to Dave of Via Negativa, who came up with the idea and hosted the very first edition of the festival, and to the many hosts who have offered their blogs for one day. You should consider being host. Just send me or Dave an email and we’ll help you along.

Occasionally, an older post starts to have a flurry of comments. The original Dave of Via Negativa post gets a few now and then. The Dave of Via Negativa posts draws some interest. Lately, it has been my post about coming across a Dave of Via Negativa in our woods that is getting some fresh comments. Of course, if you look at those comments you can see that they are being left by people who work for the companies that make these game-attracting scented candles, but the fact that it is deer hunting season around here — when these candles might be employed — probably has something to do with the increased interest.

Dave of Via Negativa I was writing about the duckweed on the pond being in retreat. Dave of Via Negativa I was musing about a perennial subject: interlopers.

What’s Pablo reading now? Well, I finished The Shadow-Line, but I’ll have to do some cogitating and maybe a little research to match it up to the Roth novel where it was repeatedly referenced. Now I’m reading The Pesthouse by Jim Crace. It’s set in a post-apocalyptic wasteland of North America, and I gave it to my daughter (who likes these kinds of stories) when she made her trip to Italy last summer. Now she’s letting me read it. I’m about a third of the way through it and I really like it. The writing is excellent, and the story is realistic for a future devoid of technology or what we would call science. No zombies or space aliens (but there’s more of the novel to read). I’d read another Crace novel years ago called Being Dead, and the two main characters in that one were, um, dead. Certainly not popular fiction.

Missouri calendar:

• Veterans Day

Posted by: Roundrockjournal      Read more     Source

October 26, 2007, 5:15 AM CT

'Nervous' birds take more risks

Researchers have shown that birds with higher stress levels adopt bolder behaviour than their normally more relaxed peers in stressful situations. A University of Exeter research team studied zebra finches, which had been selectively bred to produce three distinct types laid-back, normal and stressed based on their levels of stress hormone. The group was surprised to find that the stressed birds were bolder and took more risks in a new environment than the group that was commonly more laid-back. Their findings are published recently (26 October) in the journal Hormones and Behaviour.

Like other animals including humans, birds respond to stress, created by the appearance of a predator or a change in their environment for example, by producing a hormone. In birds, this hormone is called corticosterone and some individuals have higher levels of the hormone than others. The zebra finches in this experiment were bred to have three different corticosterone levels, with the laid-back birds having lower levels than the stressed birds. The scientists put the birds into a new environment, which housed several unfamiliar objects, including new feeders. The stressed birds were the first to visit the new feeders, which they also returned to more quickly than the other birds after being startled. Overall, they approached more objects than their normally more relaxed peers, showing greater risk-taking behaviour and arguably handling the situation better......... Posted by: Ashley      Read more         Source

Thu, 25 Oct 2007 03:45:15 GMT

Acer japonicum 'O-taki'

Along Upper Asian Way in UBC Botanical Garden is one spot that is a favourite of mine in October. Here, two poorly-known cultivars of downy Japanese maple face each other on opposite sides of the path: Acer japonicum 'O-taki' and Acer japonicum 'O-isami'. Both colour in rich shades of gold and red, and, to my memory, reliably so in Vancouver's climate.

The maple enthusiasts who participate on the maples forum have shared a few more photographs of Acer japonicum 'O-taki' throughout the seasons in the maple photograph gallery.

Wikipedia provides a broad summary of this species and its cultivars, with particular emphasis on a description of the species as well as characteristics that distinguish it from other maples with a similar appearance: Acer japonicum. Posted by: Daniel Mosquin      Read more     Source

October 24, 2007, 8:32 PM CT

Not just humans benefit from animal biotechnology

Laboratory animals are the source of major discoveries and breakthroughs in biology, not just in tackling disease but also unravelling fundamental molecular processes. Delegates at a recent research conference organised by the European Science Foundation (ESF) and Wellcome Trust heard how technology capable of analysing animal genes across the whole genome is yielding a number of benefits for agriculture and human society.

In breeding both domestic and farm animals for example, it is now possible to select individuals with a wide spectrum of desirable traits in a single generation. In the past selective breeding of animals has been confined to traits that are obvious or easy to measure, and it has been difficult to produce individuals with a broad combination of desirable qualities, as per Helen Sang, chair of the recent ESF/Wellcome conference on Animal Biotechnology.

There is the potential to increase the effectiveness of genetic selection, even for traits that are difficult or take a long time to measure, said Sang from the Roslin Institute Department of Gene Function & Development Edinburgh United Kingdom. The key point here is that it is now possible to identify individual animals for breeding, and select offspring, with the best overall combination of gene variants (alleles) rather than focusing on just one or two traits. Sang is also......... Posted by: Ashley      Read more         Source

October 17, 2007, 4:36 AM CT

Force-induced Changes in Biomolecule's Conformation

Researchers studying biological systems at the molecular level now have a new hybrid technique to probe the dynamics of the Holliday junction. The Holliday junction is a four-stranded DNA structure that forms during a process known as homologous recombination, which occurs when damaged DNA is repaired. Understanding how DNA repairs itself is an essential step in ultimately developing therapies for inherited disorders.

The hybrid technique is described by principal investigator Taekjip Ha and colleagues at the University of Illinois in the Oct. 12 issue of Science. The Holliday junction is named after geneticist Robin Holliday, who proposed the model of DNA-strand exchange in 1964. To better understand the mechanisms and functions of proteins that interact with the Holliday junction, the scientists needed a way to study the structural and dynamic properties of the junction itself.

"Based on our prior studies, we knew the Holliday junction fluctuated between two structures, but how it moved from one place to the other and what intermediates were visited along the pathway were unknown," Ha said. With this latest work, the scientists have determined that the intermediate structure is similar to that of a Holliday junction bound to its own processing enzyme.

The hybrid technique combines the exquisite force control of an optical trap and the precise measurement capabilities of single-molecule fluorescence resonance energy transfer. To use the technique, scientists first attach two dye molecules--one green and one red--to the molecule they want to study. Next, they excite the green dye with a laser. Some of the energy moves from the green dye to the red dye, depending upon the distance between them. The changing ratio of the two intensities indicates the relative movement of the two dyes. Therefore, by monitoring the brightness of the two dyes, the scientists can determine the motion of the molecule. With the optical trap, a focused laser beam locks onto a microsphere attached to one end of the molecule to be studied. The optical trap can then pull on the molecule like a pair of tweezers......... Posted by: Ashley      Read more         Source

October 11, 2007, 10:44 PM CT

New insights on green algae

Culminating a three-year research project, 115 researchers from around the world report in the Oct. 12 issue of the journal Science a "gold mine" of data on a tiny green alga called Chlamydomonas, with implications for human diseases.

The single-celled Chlamydomonas, a slimy organism that grows in soil and ponds, has approximately 15,000 genes, and researchers now know 95 percent of the sequence of its genome. Several years ago, they knew less than 2 percent.

"It's like having a dictionary of genes," said lead author Sabeeha Merchant, professor of biochemistry and associate director of UCLA's Molecular Biology Institute, who has studied the green alga for 20 years. "We know the words and now we want to learn to talk. Without the dictionary, you would be stuck and couldn't learn how to speak or write. We went from having a 200-word vocabulary to a 14,250-word vocabulary. Each of us is trying to learn how to put the words and sentences together in our own research programs.

"Having the genome sequence available fast-forwards our research by 10 or 20 years and allows us to make progress by leaps and bounds," she said. "The genome sequence opens the door for us to access all the genes and target our research on subsets of genes. What was just a dream 10 years ago, we have now accomplished"......... Posted by: Ashley      Read more         Source