An Academic Valentine: Blue for you or Pretty in pink?
Rajini Rao’s #AcademicValentine reminded me of this post about how pH can determine the color of Hydrangeas. Enjoy some science on St. Valentine’s day.
An Academic Valentine: The Science Behind Flower Color
About week ago I posted some pictures of my Hydrangeas that were just starting to bloom. http://goo.gl/Gn47h I noticed that on the same plant, some of the flowers were blue and others were pink. I knew that pH played a role but I found out that it is actually the aluminum in the soil that make the blue pigment possible. So for ScienceSunday curated by Allison Sekuler Rajini Rao Robby Bowles and me, I had to dig up more info to post along with pictures from today.
When the pH is acidic, aluminum in the soil, mostly from clay, allows a metal complex of aluminum and a anthocyanin, named delphinidin 3-monoglucoside, to form. After the pictures, the first figure is of the aluminum complex. The next figure shows various blue flowers with sections cut revealing the pigment cells and protoplasts.
Although the next two figures are about Morning glories, they were too interesting to pass up. A certain ScienceSunday co-curator always has her eyes on certain channels. Similar to the previous figure, there is a cross section-cut revealing the pigmented cells. However, the paper and figure go on to discuss how the Morning glory does not have metal complexation. The petal color changes during flower opening due to pH changes which were measured in the second part of the figure. The final figure show the purported ion channel mechanism.
Plants can be beautiful. When you throw in a dash of science, they can be beautiful and intriguing.
Edit I forgot to add that a lot of insects leave hydrangeas alone. Why? Aluminum toxicity – win – win for us gardeners.
Why is Bill Nye even doing this in the first place? The Science Guy says, “I decided to participate in the debate because I felt it would draw attention to the importance of science education here in the United States.”
“Tuesday’s debate will be about whether Ham’s creation model is viable or useful for describing nature. We cannot use his model to predict the outcome of any experiment, design a tool, cure a disease or describe natural phenomena with mathematics.
These are all things that parents in the United States very much want their children to be able to do; everyone wants his or her kids to have common sense, to be able to reason clearly and to be able to succeed in the world.”
Happy #FidoFriday This article about an old, very old, sexually transmitted cancer in dogs is being shared a lot. I think the version from Tommy Leung is clever and fun. He’s such a science hipster.
#ScienceEveryday
Originally shared by Tommy Leung
Such Transmissible Cancer. Much Old. So Doge. Wow.
Whereas there are various other pathogens/infectious agents such as the Human papillomavirus (HPV) which can trigger the growth of cancer, in the case of CTVT, it is the cancer cell itself which is the infectious agent.
Essentially, CTVT is a line of dog cells which have evolved into something that acts like a clonally-reproducing pathogen. Genetic analyses indicates that this cell line originated about 11000 years ago and that this CTVT contains traces of DNA which links it back to the earliest days of dog domestication. In a new study published in Science, it seems that the original animal which gave rise to CTVT might have been wolf-dog hybrid that was closely related to an Alaskan malamute.
For those that like science, I’m sure you can appreciate the value of having real scientists on G+ share their knowledge. Zuleyka Zevallos does an excellent job addressing 3 issues that I also work on:
Correlation does not equal causation
Sensationalized headlines are dangerous
Science outreach without jargon is important
The study itself is fascinating and her discussion of it puts a different emphasis on it that helped me gain more from it. I naturally focused on the imaging aspect.
The images that they show are volume differences from one group to another. The very complex part of it, is that you have to use a brain atlas to make sure you are comparing the hippocampus in subject A with the hippocampus in subject B, for example. The atlas is necessary because, as the study demonstrates, not everyone has the same size substructures of the brain. John Csernansky is one of my boss’s collaborators, so I can talk to him about the study.
This is why we stress in our community that posts should summarise the science behind an article in detail. The link should be there for people who want to read further (and if you write a good post, people will be more willing to click on a link!).
I’ve talked about sensationalized headlines and science outreach before:
Why Correlation is not Causation: Cannabis Use & Schizophrenia
As so often happens, a post from Science on Google+, a community I help moderate, has got me thinking about how easy it is for headlines to quickly lead to #ScienceMediaHype . A post with a link to a news story has the headline, “Teen Marijuana Use Linked with Schizophrenia” (http://goo.gl/w09d7L). As a sociologist with an interest in mental health, this sets off alarm bells. The discussion on our community quickly turned into a debate about the correlation presented in the headline. As a few of our community members pointed out, correlation does not equal causation. My post provides a summary of the actual study and I discuss the sociological problems associated with media coverage of mental illness.
Study on Working Memory
The linked article does an okay job of describing the study but the headline and its focus over-extends the study’s findings. This is the problem with media stories: headlines can shape the way the public understands scientific findings. Journalists present quotes from scientists that fit the angle of their story, putting less emphasis on other aspects of the research.
The study is published in Schizophrenia Bulletin. The sample includes 44 healthy controls, 10 people with a history of cannabis use disorder (CUD), 28 schizophrenia participants with no history of substance use, and 15 schizophrenia patients with a CUD history (http://goo.gl/EQQx2K). Ninety percent of the participants who had schizophrenia already had a CUD history prior to their mental illness. Most of the cannabis users were heavy users, smoking cannabis daily or at least weekly, and most also smoked cigarettes heavily, a variable that the researchers wanted to test.
The study actually tests working memory deficiency not the cause-effect relationship between schizophrenia and cannabis use. Participants were given memory activities and then brain imaging was used to see their brain patterns. I’ve included the three images from the study. Neuroscience is not my area of research, but I include the diagrams in case other researchers should be interested.
The researchers note that without substance abuse, schizophrenia inhibits cortical development. They note less is known about how cannabis affects brain symmetry, though it is known to disrupt the hippocampus, which is related to our limbic system. The hippocampus is linked to information retention for both short and long-term memory as well as other functions like spatial navigation.
The study finds that use of cannabis at an early age impacted memory function. The sample had an average age of 24, so patterns associated with longer-term development need further study.
The study observes that cannabis users and the participants living with schizophrenia both have problems with memory tasks. At the same time, the researchers not that the brain asymmetry observed when carrying out memory tasks may be linked to a” neurobiological vulnerability” among schizophrenia sufferers. That is, that the observed pattern may be the outcome of a predisposition to substance abuse. For example, the researchers note that similar brain patterns are found amongst cocaine users. So, to put it another way, schizophrenia users may be drawn to substance abuse. More on this below.
Finally, the authors conclude what many of our community members had been discussing: that there is no direct cause and effect relationship. “Although our data may be compatible with a causal hypothesis, the cross-sectional data do not allow us to test causal relationships or reject alternative explanations. Thus, the shape differences could be explained as either due to the effects of chronic cannabis abuse or the presence of biomarkers that characterize a vulnerability to the effects of cannabis.”
Their research notes that with laws changing, cannabis may be more readily available to youth with a predisposition towards schizophrenia. This makes their research all the more pivotal. This is both in terms of better understanding how brain development is affected by schizophrenia and the social, health and subjective reasons why youth may engage in cannabis use at different stages of their disease.
Research on Correlation
There are many studies that have linked self-reported cannabis use in early adulthood to an increased risk of developing schizophrenia later in life. One of the most widely cited studies involves Swedish conscripts of 1969, with a follow up study confirming the results (http://goo.gl/7uw0hK). Nevertheless, the direct association between cannabis use and schizophrenia is disputed. For example, there is more to be learned about the relationship between the time that someone starts using cannabis and their first schizophrenic episode (http://goo.gl/waOgfR).
There are three hypotheses to explain why young people with schizophrenia use cannabis (http://goo.gl/ZOSk7H).
1) Cannabis triggers the disease in people with a predisposition, as is suggested by the study at hand.
2) People with schizophrenia use cannabis as a way to self-medicate or manage their experience of the disease. The research does not support this strongly, though cannabis use may give sufferers a perception of control over their disease. This is not something to be dismissed and requires further research. One study from 2012 suggests that one component of marijuana, cannabidiol, may be used to treat schizophrenia. This component does not contain THC which is responsible for the intoxication effects of traditional marijuana. Instead, cannabidiol may reduce the symptoms of psychosis, but further research is needed to fully test this treatment (http://goo.gl/NPGKjm).
3) Cannabis use can trigger schizophrenia through confounding variables. This is the prevailing medical view, though the association is not so neatly weaved together.
Problems with Media Coverage of Mental Illness
The article that covered this story went for a shock value headline. Headlines prime audiences about what they should expect from a scientific article. Sensationalised headlines invite personal opinion based on individual experience. This may range from “I smoke pot and I’m fine” to disparaging comments about “crazy” people. This is the problem with the way in which news headlines shape public discussions of science. Should people read an article before discussing the soundbite? Of course. Does this happen in practice? Not as much as it should. The idea that sensational headlines “sell” is flawed. Shock headlines sometimes get people to click on a link. On a social media site like Google+, some people will go off the headline and the text in a post. In fact, most of the social media research shows that people rarely want to click away from the social site they’re currently on (more on this in another post). This is why we stress in our community that posts should summarise the science behind an article in detail. The link should be there for people who want to read further (and if you write a good post, people will be more willing to click on a link!).
While research suggests that people are sceptical of media reports, not everyone is trained to think about research the way scientists do. Paywalls also stop people from reading the study for themselves (as well as the technical language used in academic journals). This is why scientists need to step up and debunk bad science journalism.
Moving Beyond Individual Speculation
The research has established a correlation, but causation is disputed. The evidence strongly suggests that cannabis compounds schizophrenia and the gravity of this finding cannot be reduced. Nevertheless, media stories that run with a causation headline only serve to spread misinformation.
Bad science writing invites cannabis users to say: “I use it and I’m fine!” It also serves to reinforce a cultural stereotype that people with mental illness may have avoided their condition if they’d only stayed away from recreational drugs. In the end, the causation narrative does more damage and serves only to stigmatise both cannabis users and schizophrenic sufferers as deviants. People living with schizophrenia are doubly stigmatised as their cannabis use makes it seem as if they are wilfully contributing to their illness. Research is seeking to better understand why some people with schizophrenia rely on cannabis.
Mental health is a serious matter. It shouldn’t be reduced to an alarmist headline. Mental illness is part of the human condition. Addressing the treatment of schizophrenia requires compassion, not judgement. Most of all it needs solid scientific research, not dismissive condemnation based on personal or social conjecture.
Late for #ScienceSunday but there’s #ScienceEveryday . I don’t know about you, but I can’t stand The Fox (What Does the Fox Say?) by Ylvis. This video by Animalist explains what the fox actually says.
Extracting DNA from a 50,000 years ago, that suggests inbreeding among hominins is pretty fascinating. Progress in genomics reminds me of computer technology. The technology keeps getting smaller and faster.
I’ll have to go through Mark Bruce’s SciSun digests to see which news article is my favorite for 2013.
#ScienceSunday
Originally shared by ScienceSunday
Top 10 Science Stories of 2013
Here’s Scientific American’s top ten science stories of 2013.
For #caturday and #ScienceEveryday , here’s a video showing research from Prof Daniel S. Mills at University of Lincoln in the UK. He’s working on research to determine if cats are securely attached to their owners like dogs are. So far, his research has shown that dogs behave similar to infants with respect to a parent. Conversely, his research so far, shows that cats could care less. I mean, cats don’t behave in the same manner.
I had not heard of Crystallofolia before Michael O’Reilly’s post. It’s beautiful and interesting.
From Latin crystallus ice [itself from Greek κρυσταλλος; cf. κρυος ‘frost’]and folium leaf. These elegant formations have been given many names, metaphorical in nature, most commonly ‘frost flowers’ (or ribbons), a formation which is neither frost nor a flower. These common names, however, are easily confused with terms describing true frost from condensation on a cold surface as well as any picturesque ice formation. These frost metaphors are of fairly recent origin, not current with 19th Century treatments of the subject (e.g., ‘frost freak’ was used by several scholars). I thus propose folium, leaf, as a more appropriate metaphor, since like leaves these formations emerge laterally from the stem, and the enormous diversity of forms finds better matches with leaves than with flowers and ribbons — although this is perhaps less poetic. Perhaps more significantly, the physical process by which water moves to the ice formations is analogous to the transpiration that brings water from the roots to the leaves. My perspective is not new: German botanists in the 19th Century used the term ‘Eisblatt’ (‘ice leaf’).
Read the source below for more information about this phenomenon.
Last night we had our first hard freeze of the year, and the frostweed in our yard put on a little performance. Basically the water inside the frostweed freezes and extrudes from splits in the stem in fascinating ribbons and whorls. Here’s a shot of one of the splits with the ice curling around the stem. The ribbons are unbelievably thin, and it makes a pretty effect. A couple of the sections were over a foot tall, with the ice going in several directions.
This is the last post, attempting to find interesting chemistry for Siromi Samarasinghe’s birthday. Although this one isn’t about smell or being stinky, it is about civet feces.
You’ve probably heard about the really expensive coffee that’s made from an animal’s dung. It’s called Kopi Luwak. Kopi for the Indonesian word for coffee and Luwak for the Asian palm civet, Paradoxurus hermaphroditus. The luwak eats the coffee berries and digests them, imparting a unique flavor to the coffee beans. The beans are retrieved and cleaned from the luwak feces.
Jumhawan et al used gas chromatography with mass spectroscopy (GC-MS) to identify metabolites that can be used to identify genuine Kopi Luwak. From the news blurb: Kopi Luwak sports higher concentrations of malic acid and citric acid, as well as a higher ratio of inositol to pyroglutamic acid.
Selection of Discriminant Markers for Authentication of Asian Palm Civet Coffee (Kopi Luwak): A Metabolomics Approach
GC uses a long coiled tube rather than the large columns, packed with a solid phase, used in liquid chromatography. The mobile phase is gas, hence the name, and the stationary phase is a thin layer of liquid or an insert sold support.
In searching for an alternate picture for this post I found that the palm civet is being exploited due to the high price for Kopi Luwak. Many civets are being caged and feed only coffee berries.
World’s most expensive coffee tainted by ‘horrific’ civet abuse
There was a story on NPR describing a study about asymmetrical tail wagging of dogs. In 2007 Dr. Vallortigara found that a dogs tend to wag their tail to the right when they see something friendly and wag to the left when something is threatening. In 2011 Artellea et al, used a robotic dog to see how dogs would respond to a tail wagging left or right, i.e., does the tail wagging communicate fun or danger? When dogs saw the robot tail wag left, they approached without stopping. When they saw it wag to the right, they were more cautious and stopped frequently as they approached. Dr. Vallortigara followed up his previous study, this time using a video of a dog, either wagging left or right. A group of dogs watching the video had vests, which recorded their heart rate. As expected, the heart rate was normal when the tail was wagging to the right in the video and the heart rate increased (a sign of agitation) when the tail in the video was wagging to the left. The next question is how can we use this information. It should be noted how each study builds on the previous study. That’s how science works.
The image below, from Quaranta et al, 2007, shows the angle/method for determining a left or right bias tail wag. In A the tail is wagging right and in B the tail is wagging left, i.e. left and right determinations were with respect to the dog, not the observer.
EDIT for clarity.
The Tail’s The Tell: Dog Wags Can Mean Friend Or Foe
