|
|
|
|
|
|
Curious Cat Science and Egineering blog full tag cloud
I have written about statistics, and various traps people often fall into when examining data before (Statistics Insights for Scientists and Engineers, Data Can’t Lie – But People Can be Fooled, Correlation is Not Causation, Simpson’s Paradox). And also have posted about reasons for systemic reasons for medical studies presenting misleading results (Why Most Published Research Findings Are False, How to Deal with False Research Findings, Medical Study Integrity (or Lack Thereof), Surprising New Diabetes Data). This post collects some discussion on the topic from several blogs and studies.
HIV Vaccines, p values, and Proof by David Rind
How to Avoid Commonly Encountered Limitations of Published Clinical Trials by Sanjay Kaul, MD and and George A. Diamond, MD
Why Most Published Research Findings Are False by John P. A. Ioannidis
(more…)
One main difference between the two pieces of software is that for the Mars rovers, the software ran in the control centre on Earth. With this marine vehicle, it runs onboard the robotic vehicle.
…
“We tell it, ‘here’s the range of tasks that we want you to perform’, and it goes off and assesses what is happening in the ocean, making decisions about how much of the range it will cover to get back the data we want.”
Researchers at MBARI used the Gulper AUV to monitor potentially harmful algal blooms.
Kim Fulton-Bennett from MBARI explained: “We used to send out a ship for a full day every few weeks to manually take these measurements. Now we just take the AUV outside the harbour and send it on its way.
“About 24 hours later, it comes back, we hoist it on board, and download the data.”
Related: Underwater robots work together without human input – Unmanned Water Vehicles – US Navy Sponsored Technology Summer Camp
Slime Mold Grows Network Just Like Tokyo Rail System
When presented with oat flakes arranged in the pattern of Japanese cities around Tokyo, brainless, single-celled slime molds construct networks of nutrient-channeling tubes that are strikingly similar to the layout of the Japanese rail system, researchers from Japan and England report Jan. 22 in Science. A new model based on the simple rules of the slime mold’s behavior may lead to the design of more efficient, adaptable networks, the team contends.
…
The yellow slime mold Physarum polycephalum grows as a single cell that is big enough to be seen with the naked eye. When it encounters numerous food sources separated in space, the slime mold cell surrounds the food and creates tunnels to distribute the nutrients. In the experiment, researchers led by Toshiyuki Nakagaki, of Hokkaido University in Sapporo, Japan, placed oat flakes (a slime mold delicacy) in a pattern that mimicked the way cities are scattered around Tokyo, then set the slime mold loose.
…
Initially, the slime mold dispersed evenly around the oat flakes, exploring its new territory. But within hours, the slime mold began to refine its pattern, strengthening the tunnels between oat flakes while the other links gradually disappeared. After about a day, the slime mold had constructed a network of interconnected nutrient-ferrying tubes. Its design looked almost identical to that of the rail system surrounding Tokyo, with a larger number of strong, resilient tunnels connecting centrally located oats. “There is a remarkable degree of overlap between the two systems,” Fricker says.
Related: Thinking Slime Molds – Single-Celled Giant Provides New Early-Evolution Perspective – Rat Brain Cells, in a Dish, Flying a Plane – How Cells Age
From, The Greatest Show on Earth: The Evidence for Evolution by Richard Dawkins
Real wolves are pack hunters. Village dogs are scavengers that frequent middens and rubbish dumps.
…
Belyaev and his colleagues (and successors, for the experimental programme continued after his death) subjected fox cubs to standardised tests in which an experimenter would offer a cub food by hand, while trying to stroke or fondle it. The cubs were classified into three classes. Class III cubs were those that fled from or bit the person. Class II cubs would allow themselves to be handled, but showed no positive responsiveness to the experimenters. Class I cubs, the tamest of all, positively approached the handlers, wagging their tails and whining. When the cubs grew up, the experimenters systematically bred only from this tamest class.
After a mere six generations of this selective breeding for tameness, the foxes had changed so much that the experimenters felt obliged to name a new category, the “domesticated elite” class, which were “eager to establish human contact, whimpering to attract attention and sniffing and licking experimenters like dogs.” At the beginning of the experiment, none of the foxes were in the elite class. After ten generations of breeding for tameness, 18 per cent were “elite”; after 20 generations, 35 per cent; and after 30 to 35 generations, “domesticated elite” individuals constituted between 70 and 80 per cent of the experimental population.
…
The tame foxes not only behaved like domestic dogs, they looked like them. They lost their foxy pelage and became piebald black and white, like Welsh collies. Their foxy prick ears were replaced by doggy floppy ears. Their tails turned up at the end like a dog’s, rather than down like a fox’s brush. The females came on heat every six months like a bitch, instead of every year like a vixen. According to Belyaev, they even sounded like dogs.
These dog-like features were side- effects. Belyaev and his team did not deliberately breed for them, only for tameness.
The famous domesticated silver fox experiment offers interesting insight into animal traits and evolution.
Related: The Selfish Gene by Richard Dawkins – The Evolution of House Cats – Darwin’s Beetles Still Producing Surprises – Backyard Wildlife: Fox
Microcosm: E. Coli and the New Science of Life by Carl Zimmer is an excellent book. It is full of fascinating information and as usual Carl Zimmer’s writing is engaging and makes complex topics clear.
E-coli keep the level of oxygen low in the gut making the resident microbes comfortable. At any time a person will have as many as 30 strains of E. coli in their gut and it is very rare for someone ever to be free of E. coli. [page 53]
In 1943, Luria and Delbruck published the results that won them the 1969 Nobel Prize in Physiology or Medicine in which they showed that bacteria and viruses pass down their traits using genes (though it took quite some time for the scientific community at large to accept this). [page 70]
I highly recommend Microcosm, just as I highly recommend Parasite Rex, by Carl Zimmer.
Related: Bacteriophages: The Most Common Life-Like Form on Earth – Foreign Cells Outnumber Human Cells in Our Bodies – Amazing Designs of Life – Amazing Science: Retroviruses – One Species’ Genome Discovered Inside Another’s
That works in the forest, but it doesn’t work in a desert. Deserts are sandy and when the wind blows, smells scatter.
…
It’s already known that ants use celestial clues to establish the general direction home, but how do they know exactly the number of steps to take that will lead them right to the entrance of their nest?
Wolf and Whittlinger trained a bunch of ants to walk across a patch of desert to some food. When the ants began eating, the scientists trapped them and divided them into three groups. They left the first group alone. With the second group, they used superglue to attach pre-cut pig bristles to each of their six legs, essentially putting them on stilts.
…
The regular ants walked right to the nest and went inside. The ants on stilts walked right past the nest, stopped and looked around for their home…
I posted about this back in 2006: Ants on Stilts for Science, but the webcast by NPR is worth a new post.
Related: E.O. Wilson: Lord of the Ants – Huge Ant Nest – posts showing the scientific method of learning in action
Florence Nightingale: The passionate statistician
Applied statistics is a tool available to all to achieve great improvement. Unfortunately it is still very underused. As George Box says: applied statistics is not about proving a theorem, it’s about being curious about things. The goal of design of experiments is to learn and refine your experiment based on the knowledge you gain and experiment again. It is a process of discovery.
Related: articles on applied statistics – The Value of Displaying Data Well – Statistics for Experimenters – Playing Dice and Children’s Numeracy – Quality, SPC and Your Career – Great Charts
Unlike any other mammal, naked mole rate communities consist of queens and workers more reminiscent of bees than rodents. Naked mole rats can live up to 30 years, which is exceptionally long for a small rodent. Despite large numbers of naked mole-rats under observation, there has never been a single recorded case of a mole rat contracting cancer, says Gorbunova. Adding to their mystery is the fact that mole rats appear to age very little until the very end of their lives.
The mole rat’s cells express p16, a gene that makes the cells “claustrophobic,” stopping the cells’ proliferation when too many of them crowd together, cutting off runaway growth before it can start. The effect of p16 is so pronounced that when researchers mutated the cells to induce a tumor, the cells’ growth barely changed, whereas regular mouse cells became fully cancerous.
“It’s very early to speculate about the implications, but if the effect of p16 can be simulated in humans we might have a way to halt cancer before it starts.” says Vera Gorbunova, associate professor of biology at the University of Rochester and lead investigator on the discovery.
In 2006, Gorbunova discovered that telomerase—an enzyme that can lengthen the lives of cells, but can also increase the rate of cancer—is highly active in small rodents, but not in large ones.
Until Gorbunova and Seluanov’s research, the prevailing wisdom had assumed that an animal that lived as long as we humans do needed to suppress telomerase activity to guard against cancer. Telomerase helps cells reproduce, and cancer is essentially runaway cellular reproduction, so an animal living for 70 years has a lot of chances for its cells to mutate into cancer, says Gorbunova. A mouse’s life expectancy is shortened by other factors in nature, such as predation, so it was thought the mouse could afford the slim cancer risk to benefit from telomerase’s ability to speed healing.
While the findings were a surprise, they revealed another question: What about small animals like the common grey squirrel that live for 24 years or more? With telomerase fully active over such a long period, why isn’t cancer rampant in these creatures?
Related posts: Nanoparticles With Scorpion Venom Slow Cancer Spread – posts on university research – Gene Duplication and Evolution – Global Cancer Deaths to Double by 2030
(more…)
The 2009 Nobel Prize in Physics honors three scientists, who have had important roles in shaping modern information technology, with one half to Charles Kuen Kao and with Willard Sterling Boyle and George Elwood Smith sharing the other half. Kao’s discoveries have paved the way for optical fiber technology, which today is used for almost all telephony and data communication. Boyle and Smith have invented a digital image sensor – CCD, or charge-coupled device – which today has become an electronic eye in almost all areas of photography. The Nobel prize site includes great information on the science behind the research that has been honored:
Nowadays, long-distance optical communication uses single mode fibers almost exclusively, following Kao’s vision. The first such systems used frequent electronic repeaters to compensate for the remaining losses. Most of these repeaters have now been replaced by optical amplifiers, in particular erbium-doped fiber amplifiers. Optical communication uses wavelength division multiplexing with different wavelengths to carry different signals in the same fiber, thus multiplying the transmission rate. The first non-experimental optical fiber links were installed in 1975 in UK, and soon after in the US and in Japan. The first transatlantic fiber-optic cable was installed in 1988.
Related: How telephone echoes lead to digital cameras – 2007 Nobel Prize in Physics – 2006 Nobel Prize in Physics – posts on Nobel laureates
This year’s Nobel Prize in Physiology or Medicine is awarded to three scientists who have solved a major problem in biology: how the chromosomes can be copied in a complete way during cell divisions and how they are protected against degradation. The Nobel Laureates have shown that the solution is to be found in the ends of the chromosomes – the telomeres – and in an enzyme that forms them – telomerase.
The long, thread-like DNA molecules that carry our genes are packed into chromosomes, the telomeres being the caps on their ends. Elizabeth Blackburn and Jack Szostak discovered that a unique DNA sequence in the telomeres protects the chromosomes from degradation. Carol Greider and Elizabeth Blackburn identified telomerase, the enzyme that makes telomere DNA. These discoveries explained how the ends of the chromosomes are protected by the telomeres and that they are built by telomerase.
If the telomeres are shortened, cells age. Conversely, if telomerase activity is high, telomere length is maintained, and cellular senescence is delayed. This is the case in cancer cells, which can be considered to have eternal life. Certain inherited diseases, in contrast, are characterized by a defective telomerase, resulting in damaged cells. The award of the Nobel Prize recognizes the discovery of a fundamental mechanism in the cell, a discovery that has stimulated the development of new therapeutic strategies.
Scientists began to investigate what roles the telomere might play in the cell. Szostak’s group identified yeast cells with mutations that led to a gradual shortening of the telomeres. Such cells grew poorly and eventually stopped dividing. Blackburn and her co-workers made mutations in the RNA of the telomerase and observed similar effects in Tetrahymena. In both cases, this led to premature cellular ageing – senescence. In contrast, functional telomeres instead prevent chromosomal damage and delay cellular senescence. Later on, Greider’s group showed that the senescence of human cells is also delayed by telomerase. Research in this area has been intense and it is now known that the DNA sequence in the telomere attracts proteins that form a protective cap around the fragile ends of the DNA strands.
Many scientists speculated that telomere shortening could be the reason for ageing, not only in the individual cells but also in the organism as a whole. But the ageing process has turned out to be complex and it is now thought to depend on several different factors, the telomere being one of them. Research in this area remains intense.
The 3 awardees are citizens of the USA; two were born elsewhere.
Read more about their research at the Nobel Prize web site.
Molecular biologist Elizabeth Blackburn–one of Time magazine’s 100 “Most Influential People in the World” in 2007–made headlines in 2004 when she was dismissed from the President’s Council on Bioethics after objecting to the council’s call for a moratorium on stem cell research and protesting the suppression of relevant scientific evidence in its final report.
Related: Nobel Prize in Physiology or Medicine 2008 – 2007 Nobel Prize in Physiology or Medicine – 2006 Nobel Prize in Physiology or Medicine
Webcast of Dr. Elizabeth Blackburn speaking at Google:
(more…)
Put It to the Test is one of the songs on the great new Album and animated DVD from They Might Be Giants: Here Comes Science.
A fun song on fundamentals of experimenting to the scientific method.
Related: Here Comes Science by They Might Be Giants – posts on experimenting – MythBuster: 3 Ways to Fix USA Science Education – Science Toys You Can Make With Your Kids – Correlation is Not Causation
Why do we need dark energy to explain the observable universe?
Another interesting example of the scientific inquiry process at work in cosmology.
Shouldn’t the National Academy of Science (NAS), a congressionally chartered institution, promote open science instead of erecting pay walls to block papers from open access? The paper (by 2 public school professors) is not freely available online. It seems like it will be available 6 months after publication (which is good) but shouldn’t the NAS do better? Delayed open access, for organizations with a focus other than promoting science (journal companies etc.), is acceptable at the current time, but the NAS should do better to promote science, I think.
Related: Physics from Universe to Multiverse – Laws of Physics May Need a Revision – Extra-Universal Matter – Cosmology Questions Answered
By examining data from the Whitehall Study researchers have found smokers with high blood pressure and high cholesterol in middle age died 10 years earlier than the others after reaching age 50. This is independent of changes after later in life (quiting smoking, etc.). Life expectancy in relation to cardiovascular risk factors: 38 year follow-up of 19,000 men in the Whitehall study
Conclusion Despite substantial changes in these risk factors over time, baseline differences in risk factors were associated with 10 to 15 year shorter life expectancy from age 50.
Another conclusion: if you don’t want to live a shorter life, don’t smoke. Not a new idea but given how many people continue to smoke it seems some don’t understand this conclusion.
Related: Global Cancer Deaths to Double by 2030 – Leading Causes of Death – more posts on open access papers – Study Finds Obesity as Teen as Deadly as Smoking
Scientific literacy is important for many reasons and that importance has increased greatly over the last century. Medical research is often difficult to interpret. Often various studies seem to contradict each other. Often the conclusions that are drawn are far too broad (especially as the research conclusions are passed on and people hear of them overly simplified ways).
Many health care options are not obviously all good, or all bad, but instead a mix of benefits and risks, both of which include interactions with the individuals makeup. So we often see contradictory (and seemingly contradictory) advice. Without a level of scientific literacy it is very difficult for people to know how to react to medical advice.
We have numerous posts on the scientific inquiry process showing that acquiring scientific knowledge is complex and can be quite confusing in many instances. While understanding things are often less clear cut than they are presented it is still true that most often strategies for healthy living have far better practices that will provide far better results than alternatives.
The scientific illiteracy that has some think because their are risks no matter what is done that means there is no evidence some alternatives are far superior is very dangerous. As you can see in action now with those that risk their and others lives and health by doing things like not vaccinating their children, or driving when drunk, or driving when talking on a cell phone.
Without a scientifically literate society even completely obvious measures like not using antibiotics on viral infections are ignored.
Related: Long Term ADHD Drug Benefits Questioned – How Prozac Sent Science Inquiry Off Track – Lifestyle Drugs and Risk – Correlation is Not Causation: “Fat is Catching” Theory Exposed
(more…)
Sunflower photo from WikiMedia – Helianthus Annuus ‘Taiyo’The Great Sunflower Project provides a way for you to engage in the ongoing study of bees and colony collapse disorder. The study uses the annual Lemon Queen sunflowers (Helianthus annuus), that can be grown in a pot on a deck or patio or in a garden (and they will send you seeds).
How do bees make fruits and vegetables?
All flowers have pollen. Bees gather pollen to feed their babies which start as eggs and then grow into larvae. It’s the larvae that eat the pollen. Bees use the nectar for energy. When a bee goes to a flower in your garden to get nectar or pollen, they usually pick up pollen from the male part of the flower which is called an anther. When they travel to the next flower looking for food, they move some of that pollen to the female part of the next plant which is called a stigma. Most flowers need pollen to make seeds and fruits.
After landing on the female part, the stigma, the pollen grows down the stigma until it finds an unfertilized seed which is called an ovary. Inside the ovary, a cell from the pollen joins up with cells from the ovary and a seed is born! For many of our garden plants, the only way for them to start a new plant is by growing from a seed Fruits are just the parts of the plants that have the seeds. Some fruits are what we think of as fruits when we are in the grocery store like apples and oranges. Other fruits are vegetables like tomatoes and cucumbers and peppers.
Related: Monarch Butterfly Migration – Solving the Mystery of the Vanishing Bees – Volunteers busy as bees counting population – The Science of Gardening
WHO Director-General, Dr Margaret Chan, announced today that she has “decided to raise the current level of influenza pandemic alert from phase 4 to phase 5.” And she further comments:
Let me remind you. New diseases are, by definition, poorly understood. Influenza viruses are notorious for their rapid mutation and unpredictable behaviour. WHO and health authorities in affected countries will not have all the answers immediately, but we will get them.
WHO will be tracking the pandemic at the epidemiological, clinical, and virological levels. All countries should immediately activate their pandemic preparedness plans. Countries should remain on high alert for unusual outbreaks of influenza-like illness and severe pneumonia.
At this stage, effective and essential measures include heightened surveillance, early detection and treatment of cases, and infection control in all health facilities.
I have reached out to companies manufacturing antiviral drugs to assess capacity and all options for ramping up production. I have also reached out to influenza vaccine manufacturers that can contribute to the production of a pandemic vaccine.
The biggest question, right now, is this: how severe will the pandemic be, especially now at the start?
It is possible that the full clinical spectrum of this disease goes from mild illness to severe disease. We need to continue to monitor the evolution of the situation to get the specific information and data we need to answer this question.
From past experience, we also know that influenza may cause mild disease in affluent countries, but more severe disease, with higher mortality, in developing countries.
No matter what the situation is, the international community should treat this as a window of opportunity to ramp up preparedness and response.
Above all, this is an opportunity for global solidarity as we look for responses and solutions that benefit all countries, all of humanity. After all, it really is all of humanity that is under threat during a pandemic.
As I have said, we do not have all the answers right now, but we will get them.
—- end of her remarks —-
The latest WHO Epidemic and Pandemic Alert and Response release puts the total number of confirmed cases at 148, in 9 countries, with 8 deaths. Mexico has many more suspected cases but just 26 confirmed cases. The CDC Swine Influenza site, puts the total number of confirmed cases in the USA at 91, in 10 states, with 1 death.
Related: Swine Flu: a Quick Overview – Swine Flu One Step Closer to Pandemic – posts on influenza – Why the Flu Likes Winter – Reducing the Impact of a Flu Pandemic
Curious Cat Science and Engineering Blog © curiouscat.com 2005-2008 powered by WordPress
USA High School Alumni
