| JAMES COOK UNIVERSITY |
The demise of big trees will have major impacts on biodiversity and forest ecology, while worsening climate change.
Image: 123render/iStockphoto
Already on the decline worldwide, big trees face a dire future according to James Cook University’s Distinguished Professor William Laurance.
Writing in New Scientist magazine, Professor Laurance said that the world’s "biggest and most magnificent" trees face a range of threats. Reviewing research from forests around the world, he said that there was evidence of their decline due to habitat fragmentation, selective harvesting by loggers, exotic invaders, and the effects of climate change. He said their demise will have substantial impacts on biodiversity and forest ecology, while worsening climate change. "To persist, big trees need a safe place to live and long periods of stability," Professor Laurance said. "But time and stability are becoming very rare commodities in our modern world." Giant trees offer critical habitat and forage for wildlife, while transpiring massive amounts of water through their leaves, contributing to local rainfall. Old trees also lock up massive amounts of carbon — in some forests they can account for more than a quarter of living biomass. “But their ability to sequester carbon and render other ecosystem services is threatened by human activities. Some of the world's largest trees are particularly targeted by loggers. The oldest trees are among the most valuable and therefore the first to be cut in ‘virgin’ forest areas,” he said. “Big trees are also sensitive to habitat fragmentation, which exposes them to stronger winds and drier conditions.” Professor Laurance's own work in the Amazon has shown substantial die-off of canopy giants in small forest fragments. “Their susceptibility seems counter-intuitive given big trees' life histories, which invariably include periods of drought and other stress,” he said. "All around the tropics, big canopy and emergent trees are succumbing to strong droughts. "That's been a surprise to me and many other ecologists, because big, ancient trees would have had to survive many droughts in the past." Professor Laurance said that forest giants may suffer disproportionately from climate change. "According to one popular theory, trees get a double-whammy when the thermometer rises. During the day, their photosynthesis shuts down when it gets too warm, and at night they use more energy because their metabolic rate increases, much as a reptile’s would do when it gets warmer. “With less energy being produced in warmer years and more being consumed just to survive, there is less energy available for growth. “This hypothesis, if correct, means tropical forests could shrink over time. The largest, oldest trees would progressively die off and tend not to be replaced,” Professor Laurance said. “Alarmingly, this might trigger a positive feedback that could destabilize the climate: as older trees die, forests would release some of their stored carbon into the atmosphere, prompting a vicious circle of further warming, forest shrinkage and carbon emissions.” Professor Laurance said that climate change was also having less direct impacts on forests, including creating conditions for exotic pathogens to thrive. For example, pathogens such as Dutch Elm Disease, introduced by trade or circumstance, have devastated trees in many parts of the world. “All told, the outlook for big trees is not good,” he said. "The decline of big trees foretells a different world where ancient behemoths are replaced by short-lived pioneers and generalists that can grow anywhere, where forests store less carbon and sustain fewer dependent animals. “It’s a place where giant cathedral-like crowns could become a thing of the past."
Editor's Note: Original news release can be found here.
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Thursday, February 9, 2012
‘Dire future’ awaits big trees
Smoking dads: leukemic kids
| LOUISA FREW, SCIENCENETWORK WA |
“Oxidative damage to the DNA is the main type of damage seen as a result of smoking in sperm."
Image: Stratol/iStockphoto
Research from Western Australia’s Telethon Institute for Child Health Research finds that heavy smoking by fathers around the time of conception greatly increases the risk of the child developing Acute Lymphoblastic Leukaemia (ALL), the most common form of childhood cancer.
Published in the prestigious American Journal of Epidemiology, the study investigated the association between parental smoking and the occurrence of ALL in offspring. “The first step towards the development of leukemia is thought to occur in utero in a lot of cases,” lead author Dr Elizabeth Milne says. “So we look at prenatal exposures as it has to be something to do with what’s happening before the baby’s born.” “Tobacco is a known carcinogen and, in terms of childhood leukemia, there’s a plausible biological pathway whereby paternal smoking could actually contribute to disease risk in the offspring,” she says. In a comprehensive exposure questionnaire distributed nationwide to 388 families with cases of ALL and 868 control families, the group asked mothers and fathers to state where they lived, their occupation and how many cigarettes they smoked for every year of their life from the time they were 15. “Using this information and knowing the year the child was born, we were then able to look at smoking levels around the time of conception,” Dr Milne says. “The results indicated that the risk of ALL, when compared with dad’s who did not smoke during the year of conception, increased by 35% when fathers smoked more than 15 cigarettes a day around the time conception.” The effect was only apparent amongst heavier smokers, with fathers who smoked less than 15 cigarettes, as well as former heavy smokers, not showing any increased risk. Based on evidence from laboratory studies of sperm, the group believe that paternal smoking may cause adverse changes in sperm DNA structure that may then go on to effect the development of the baby. “Oxidative damage to the DNA is the main type of damage seen as a result of smoking in sperm,” Dr Milne says. Dr Milne cautions against implying blame, stating the cause of ALL is likely to be multifactor and that research efforts are about prevention in the future. “The key message is that this is something that fathers and potential fathers should be informed of,” she says. The group hope to further this research by looking at the paternal and offspring genotype in terms of DNA repair mechanisms to assess if there may be effect-modification by genotype.
Editor's Note: Original news release can be found here.
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Climate raises risk of dengue
| ROB PAYNE, SCIENCENETWORK WA |
The Asian tiger mosquito is known to carry several viruses, including dengue fever.
Image: flubydust/iStockphoto
According to climate modelling for 2050, northern sections of WA could present ideal conditions for dengue fever.
At present the receptive region for the mosquito Aedes aegypti—a vector for the disease—is confined to the northern part of Australia with sporadic incidences in Queensland. But in a high-emissions temperature scenario, this zone could spread along the coast from the Northern Territory border as far south as Carnarvon. These findings were part of Professor Anthony McMichael’s Australian Academy of Science (AAS) public lecture Pestilence, pandemics and climate change, presented at Shine Dome, Canberra. Sometimes known as ‘bone-break fever’, dengue symptoms include elevated temperature, joint ache, severe headaches, weakness and skin rashes. Five per cent of cases are fatal. In the first quarter of 2011, 166 cases were reported in WA, up from 85 in 2010. These originated overseas, with 80 percent traced to Indonesia. According to Prof McMichael, changes in temperature and rainfall patterns will influence the emergence and spread of infectious diseases across Australia. “These particularly include dengue fever and Ross River Virus as well as the major causes of gastroenteritis or food poisoning,” he says. “There is also an increased likelihood of new infectious diseases emerging.” In his lecture, Prof McMichael traces the ebb and flow of pestilence, pandemics and climate change, linking periods of global warming and cooling to spikes in infectious disease. He notes that small changes in climate can have high impacts. During the Justinian Plague of 542, a three to four degree cooling event combined with unusual rain levels resulted in conditions rife for the proliferation of the xenopsylla cheopsis flea—carrier of the bubonic plague. Similarly, during the Black Death, a 1 degree C rise in spring temperatures correlated to an increase in human plague outbreaks by 63 percent. As our temperatures rise, WA, like the rest of Australia, should be prepared for rapid ecological change. “In terms of food yields, any departure from average climate conditions will put a strain on food species—plant and animals,” says Prof McMichael. He notes bats infected with the Hendra virus in Asia have moved closer into peri-urban settings due to loss of habitat caused in part by temperature change and altered rainfall patterns. By logical conjecture, similar migrations could affect WA, including incidences of Ross River Virus (RRV) and Barmah Forest Virus (BFV), which are transmitted through intermediary animals.
Editor's Note: Original news release can be found here.
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Bionic eye trials ready in 2013
| MONASH UNIVERSITY |
Over 50,000 people in Australia are considered clinically blind while the number globally exceeds 160 million.
Image: [name here]/iStockphoto
Monash University researchers say they will have a bionic eye implant ready for human trials in 2013.
“We have made significant progress since beginning last year and are confident we will have a device that could treat the majority of patients who are clinically blind,” said Professor Arthur Lowery, Director of the Monash Vision Group (MVG). Over 50,000 people in Australia are considered clinically blind while the number globally exceeds 160 million. “Our device will directly stimulate the brain’s vision centre using a miniaturised implant. The implant is fed with signals from a camera that have been processed to extract the most useful information, depending on what the user needs. “The implant has many tiles, each with 45 electrodes, designed to give over 650 pixels in all. Due to the powerful and adaptable signal processing, we believe this number of electrodes can provide invaluable situational awareness to the user. The device can also be tuned for use in different environments, both indoors and outdoors,” Prof Lowery said. The MVG approach has a number of advantages over other bionic eye technologies, in that it does not require a functioning eyeball or optic nerve or visual pathways from the eye to the brain.
Prof Jeffrey Rosenfeld, chief surgeon on the project from The Alfred Hospital in Melbourne, believes that this approach will suit patients who have lost their sight through traumatic injury or tumours, and will also be suitable for many patients with diseases affecting the eye itself, such as glaucoma and retinal disorders.
“Our implant features an array of electrodes inserted into the surface layers of the brain at the back of the head where the V1 vision region resides. The V1 region has a relatively large surface area compared with the retina, so can potentially provide better resolution than other approaches,” Prof Rosenfeld said.
Established in April 2010, with an $8 million grant from the Australian Research Council, MVG consists of more than 20 leaders in physiology, neurosurgery, ophthalmology, electrical and electronic engineering, mechanical and materials engineering, mathematics and immunology.
The MVG’s key partners include Monash University, Grey Innovation, Alfred Health and MiniFab, with the group also exploring the potential to collaborate with other leading researchers and engineers from Australia, the US and UK.
Editor's Note: More information about the research can be found here.
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The photographer caught this special moment, what a privilege to see!
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IT'S HARD TO SAY WHICH IS MORE AMAZING... THE ANIMALS OR THE PHOTOGRAPHY!!!
"Be who you are and say what you feel...Because those that matter...don't mind...
And those that mind....don't matter."
Adolescents suffering from depression more likely to be bullied
A new study provides evidence that adolescents who suffer from depression are more likely to develop difficulty in peer relationships including being bullied at school.
It's often assumed that being bullied leads to psychological problems, such as depression, but the study doesn't support this line of thought.
"Often the assumption is that problematic peer relationships drive depression. We found that depression symptoms predicted negative peer relationships," said Karen Kochel, Arizona State University School of Social and Family Dynamics assistant research professor. "We examined the issue from both directions but found no evidence to suggest that peer relationships forecasted depression among this school-based sample of adolescents."
The new research is published in the journal Child Development. The article, Longitudinal Associations among Youths' Depressive Symptoms, Peer Victimization, and Low Peer Acceptance: An Interpersonal Process Perspective, was authored by: Arizona State University School of Social and Family Dynamics Professor Gary Ladd; Karen Kochel, who conducted the study for her dissertation; and Karen Rudolph of the University of Illinois.
Being depressed in fourth grade predicted peer victimization in fifth grade and difficulty with peer acceptance in sixth grade, according to the research.
The researchers examined data from 486 youths from fourth to sixth grade. Parents, teachers, peers and students themselves provided information through yearly surveys. Data was collected as part of a large-scale longitudinal study that began in 1992 and continued for nearly two decades.
"Adolescence is the time when we see depressive symptoms escalate, particularly in girls," Kochel said. This may be due to the onset of puberty or interpersonal challenges, such as emotionally demanding peer and romantic relationships, which are often experienced during adolescence.
Teachers and parents were asked to identify classic signs of depression – crying a lot, lack of energy, etc. - when determining which children suffered from the malady. They defined peer victimization as bullying that was manifested physically, verbally, or relationally, such as hitting someone, saying mean things, talking behind someone's back or picking on someone.
"Teachers, administrators and parents need to be aware of the signs and symptoms of depression and the possibility that depression is a risk factor for problematic peer relations," Kochel said.
Research shows that having positive peer relationships is crucial for adapting to certain aspects of life such as scholastic achievement and functioning in a healthy manner psychologically, Kochel said.
"If adolescent depression forecasts peer relationship problems, then recognizing depression is very important at this particular age. This is especially true given that social adjustment in adolescence appears to have implications for functioning throughout an individual's lifetime," Kochel said.
School may be the best place to observe and address adolescent signs of depression since students typically start spending more time with their friends and less with their parents as they become adolescents, according to the social scientists.
"We studied peer relationships within the school context. Parents tend not to observe these relationships," Kochel said. "Because depression has the potential to undermine the maturation of key developmental skills, such as establishing healthy peer relationships, it's important to be aware of the signs and symptoms of adolescent depression."
Provided by Arizona State University
"New study: Adolescents suffering from depression more likely to be bullied." February 8th, 2012. http://medicalxpress.com/news/2012-02-adolescents-depression-bullied.html
Posted by
Robert Karl Stonjek
Robert Karl Stonjek
Is it ever ok to hug your doctor?
To hug or not to hug, that really is the question. We’ve all had those awkward moments. Should I go in for the hug? I’m not a hugger, what should I do? What about in the medical setting? Is it ever OK to hug your doctor?
There is something very unique about the patient/physician relationship. It’s a delicate relationship that can only thrive on open, trusted communication, yet there needs to be clear-set boundaries. This delicate balance often can result in some gray areas.
“Even in our current high-tech medicine age, it is clear that the relationship between the patient and caregiver is of therapeutic benefit. Still, professional boundaries need to be established. A simple matter such as hugging is complex because being a doctor or a nurse is a complex role that combines job skills and one’s very being,” said Mark Kuczewski, PhD, director of the Neiswanger Institute for Bioethics and Health Policy, Loyola University Chicago.
A clinical setting can be a place of highly charged emotions. This is where life-and-death information is discussed and exchanged. Just being in this environment can have strong emotional implications and a patient may need reassurance, comfort and support.
Kuczewski said that when encountering these awkward moments, there are a few things to take into consideration.
First, context is key. Professional distance is important in the physician/patient relationship. If a doctor has an objective, neutral tone it creates a judgment-free environment where a patient feels free to discuss any topic.
“There are emotionally charged situations that can happen in a clinical setting. If a patient has developed a rapport with a caregiver, they may reach out for a sign of support such as a hug. If it seems natural and unforced, it may be helpful and probably of no real concern,” Kuczewski said.
Second, it is important that the person who initiates the hug is the less-powerful person.
“When people who are very ill come to see a physician, they are extremely vulnerable. They feel their health and well-being lies in the hands of this physician and they don’t want to offend him or her. This can make it hard for a patient to decline a hug for fear of it impacting their care,” Kuczewski said.
Still, at times the physician may be the less powerful person or just feel uncomfortable accepting a hug from a patient. In those instances Kuczewski recommends trying to inject a handshake before the person moves in for a hug. If caught early enough, both physician and patient will feel the professional boundaries have not been crossed, but there still has been a comforting connection.
“While it might seem awkward at the moment, setting such boundaries immediately is far less uncomfortable than having to dispel the patient’s misconceptions later on,” Kuczewski said.
He offers some additional ways physicians can still show concern for their patients without a hug. Doctors should:
Use body nonverbal cues that one is paying attention, such as leaning forward, facing the patient when talking and making eye contact.
Touch an elbow or forearm. This is less invasive than a hug.
Use verbal cues to show expressions of support such as, “We’re in this together,” if the patient is receiving bad news.
“What’s important is solidifying the patient/physician relationship, showing support in a non-threatening way,” Kuczewski said.
These situations are most difficult when the nature of the affection might be misunderstood by the patient or physician.
“When in doubt, substitute a handshake or other sign of support, and doubt early and often. Any time you question a hug, don’t do it. You can graciously and easily deflect the momentum toward a hug by extending a hand for a handshake or providing a comforting word,” Kuczewski said. “Still, in the right context and with the right people, a hug might be just what the doctor and the patient ordered. We don’t want to deny a patient or physician a moment that can bring healing."
Provided by Loyola University Health System
"Is it ever ok to hug your doctor?." February 8th, 2012. http://medicalxpress.com/news/2012-02-doctor.html
Posted by
Robert Karl Stonjek
Robert Karl Stonjek
Flipping a light switch in the cell: Quantum dots used for targeted neural activation
Optically excited quantum dots in close proximity to a cell control the opening of ion channels. Credit: Lugo et al., University of Washington
By harnessing quantum dots—tiny light-emitting semiconductor particles a few billionths of a meter across—researchers at the University of Washington (UW) have developed a new and vastly more targeted way to stimulate neurons in the brain. Being able to switch neurons on and off and monitor how they communicate with one another is crucial for understanding—and, ultimately, treating—a host of brain disorders, including Parkinson's disease, Alzheimer's, and even psychiatric disorders such as severe depression. The research was published today in the Optical Society's (OSA) open-access journalBiomedical Optics Express.
Doctors and researchers today commonly use electrodes—on the scalp or implanted within the brain—to deliver zaps of electricity to stimulate cells. Unfortunately, these electrodes activate huge swaths of neural territory, made up of thousands or even millions of cells, of many different types. That makes it impossible to tease out the behavior of any given cell, or even of particular cell types, to understand cellular communication and how it contributes to the disease process.
Ideally, nerve cells would be activated in a non-invasive way that is also highly targeted. A promising method for doing this is photostimulation—essentially, controlling cells with light. Recently, for example, a team of Stanford University researchers altered mammalian nerve cells to carry light-sensitive proteins from single-celled algae, allowing the scientists to rapidly flip the cells on and off, just with flashes of light. The problem with this process, however, is that the light-controlled cells must be genetically altered to perform their parlor trick.
Optically excited quantum dots in close proximity to a cell control the opening of ion channels. Credit: Image adapted fromJiang et al., Chem. Mater., 2006, 18 (20), pp 4845-4854.
In the paper published today, Lin, Rieke and colleagues have extended the use of quantum dots to the targeted activation of cells. In laboratory experiments, the researchers cultured cells on quantum dot films, so that the cell membranes were in close proximity to the quantum-dot coated surfaces. The electrical behavior of individual cells was then measured as the cells were exposed to flashes of light of various wavelengths; the light excited electrons within the quantum dots, generating electrical fields that triggered spiking in the cells.
"We tried prostate cancer cells first because a colleague happened to have the cell line and experience with them, and they are resilient, which is an advantage for culturing on the quantum dot films," Lin says. "But eventually we want to use this technology to study the behavior of neurons, so we switched to cortical neurons after the initial success with the cancer cells."
The experiments, says Lin, show that "it is possible to excite neurons and other cells and control their activities remotely using light. This non-invasive method can provide flexibility in probing and controlling cells at different locations while minimizing undesirable effects."
"Many brain disorders are caused by imbalanced neural activity," Rieke adds, and so "techniques that allow manipulation of the activity of specific types of neurons could permit restoration of normal—balanced—activity levels"—including the restoration of function in retinas that have been compromised by various diseases. "The technique we describe provides an alternative tool for exciting neurons in a spatially and temporally controllable manner. This could aid both in understanding the normal activity patterns in neural circuits, by introducing perturbations and monitoring their effect, and how such manipulations could restore normal circuit activity."
So far, the technique has only been applied to cells cultured outside the body; to gain insight into disease processes and be clinically useful, it would need to be performed within living tissue. To do so, Lin says, "we need to modify the surface of the quantum dots so that they can target specific cells when injected into live animals." The dots also need to be non-toxic, unlike those used in the Biomedical Optics Express report, which often had detrimental effects on the cells to which they were attached. "One solution would be developing non-toxic quantum dots using silicon," Lin says.
More information: "Remote switching of cellular activity and cell signaling using light in conjunction with quantum dots (http://www.opticsi … =boe-3-3-447
Provided by Optical Society of America
"Flipping a light switch in the cell: Quantum dots used for targeted neural activation." February 8th, 2012. http://www.physorg.com/news/2012-02-flipping-cell-quantum-dots-neural.html
Posted by
Robert Karl Stonjek
Robert Karl Stonjek
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