Abstract: Cycling is popular among children, but results in thousands of injuries annually. In recent years, many states and localities have enacted bicycle helmet laws. We examine direct and indirect effects of these laws on injuries. Using hospital-level panel data and triple difference models, we find helmet laws are associated with reductions in bicycle-related head injuries among children. However, laws also are associated with decreases in non-head cycling injuries, as well as increases in head injuries from other wheeled sports. Thus, the observed reduction in bicycle-related head injuries may be due to reductions in bicycle riding induced by the laws.
[FULL TEXT PDF] [more inside]
posted by Blasdelb
on Feb 27, 2013 -
157 comments
False memories of fabricated political events [ABSTRACT]. In the largest false memory study to date, 5,269 participants were asked about their memories for three true and one of five fabricated political events. Each fabricated event was accompanied by a photographic image purportedly depicting that event. Approximately half the participants falsely remembered that the false event happened, with 27% remembering that they saw the events happen on the news. Political orientation appeared to influence the formation of false memories, with conservatives more likely to falsely remember seeing Barack Obama shaking hands with the president of Iran, and liberals more likely to remember George W. Bush vacationing with a baseball celebrity during the Hurricane Katrina disaster. A follow-up study supported the explanation that events are more easily implanted in memory when they are congruent with a person's preexisting attitudes and evaluations, in part because attitude-congruent false events promote feelings of recognition and familiarity, which in turn interfere with source attributions.
[FULL TEXT PDF AVAILABLE HERE] [more inside]
posted by Blasdelb
on Feb 13, 2013 -
78 comments
The practice of lying to one's children to encourage behavioral compliance was investigated among parents in the US (N = 114) and China (N = 85). The vast majority of parents (84% in the US and 98% in China) reported having lied to their children for this purpose. Within each country, the practice most frequently took the form of falsely threatening to leave a child alone in public if he or she refused to follow the parent. Crosscultural differences were seen: A larger proportion of the parents in China reported that they employed instrumental lie-telling to promote behavioral compliance, and a larger proportion approved of this practice, as compared to the parents in the US. This difference was not seen on measures relating to the practice of lying to promote positive feelings, or on measures relating to statements about fantasy characters such as the tooth fairy.
Findings are discussed with reference to sociocultural values and certain parenting-related challenges that extend across cultures. [HTML] --
[PDF] [more inside]
posted by Blasdelb
on Jan 23, 2013 -
82 comments
The Norovirus: A Study in Puked Perfection, "Each norovirus carries just nine protein-coding genes (you have about 20,000). Even with that skimpy genetic toolkit, noroviruses can break the locks on our cells, slip in, and hack our own DNA to make new noroviruses. The details of this invasion are sketchy, alas, because scientists haven’t figured out a good way to rear noroviruses in human cells in their labs. It’s not even clear exactly which type of cell they invade once they reach the gut. Regardless of the type, they clearly know how to exploit their hosts. Noroviruses come roaring out of the infected cells in vast numbers. And then they come roaring out of the body. Within a day of infection, noroviruses have rewired our digestive system so that stuff comes flying out from both ends."
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posted by Blasdelb
on Jan 3, 2013 -
120 comments
Association of Coffee Drinking with Total and Cause-Specific Mortality [FULL TEXT HTML]: "We used data from a very large study,
the National Institutes of Health (NIH)–AARP Diet and Health Study (
ClinicalTrials.gov number, NCT00340015), to determine whether coffee consumption is associated with total or cause-specific mortality. The current analysis, involving more than 400,000 participants and 52,000 deaths, had ample power to detect even modest associations and allowed for subgroup analyses according to important baseline factors, including the presence or absence of adiposity and diabetes, as well as cigarette-smoking status."
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posted by Blasdelb
on Dec 25, 2012 -
85 comments
Our study, “Bicyclists’ Injuries and the Cycling Environment” (the BICE Study),
examined which route types are associated with higher and lower cycling injury risk. It examined the association between bicyclists’ injuries and the cycling environment (e.g., route types, intersection types). Taking place in Toronto and Vancouver between May 2008 and November 2009, the participants were adults who were injured while bicycling and who attended hospital emergency departments for treatment. Five hospitals recruited participants, 690 in total.
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posted by Blasdelb
on Oct 31, 2012 -
91 comments
One of the many problems farmers of various kinds of legumes need to deal with is the
pea aphid. They reproduce incredibly fast and live by sucking the sap out of the plants,
an electron micrograph of one in action. However, while they are terrifying parasites of legumes, they have their own yet more horrific parasites, a
parasitoid wasp.
Here is a really nice close up picture of one doing its thing,
a video of the act, and
here is a brain meltingly horrific video of a dissection of the mummified aftermath 8 days later. Essentially,
these wasps deposit their eggs in a pea aphid and the growing larva feeds on it, developing there for about a week, and then consuming the host from the inside out like a
Xenomorph. When it’s done, the wasp larva dries the aphid’s cuticle into a papery brittle shell and an adult wasp emerges from the aphid mummy. Legume farmers love them,
and you can even order their mummies online these days. However, farmers noticed that the wasps didn't work as effectively on all of the aphids, and so researchers went to work figuring out why. It turns out that all aphids have a
primary bacterial endosymbiont living inside their cells, in addition to and just like a mitochondria, and that many have some combination of five other secondary endosymbionts. Interestingly, two of those other five,
Hamiltonella defensa and
Serratia symbiotica have been shown to confer varying levels of resistance to the parasitoid wasp, allowing the aphid to survive infection. However, it turns out that there is yet one more layer to this story,
[more inside]
posted by Blasdelb
on Oct 22, 2012 -
50 comments
"Why do parasites harm their hosts? Conventional wisdom holds that because parasites depend on their hosts for survival and transmission, they should evolve to become benign, yet many parasites cause harm. Theory predicts that parasites could evolve virulence (i.e., parasite-induced reductions in host fitness) by balancing the transmission benefits of parasite replication with the costs of host death. This idea has led researchers to predict how human interventions—such as vaccines—may alter virulence evolution, yet empirical support is critically lacking."
Two papers demonstrate empirical evidence for related models predicting the origin of virulence:
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posted by Blasdelb
on Oct 21, 2012 -
23 comments
Mitigating Mutational Meltdown in Mammalian Mitochondria PLoS Biol 6(2): e35. [The PDF, where you can read the paper in its much prettier intended format.]Mitochondria are remarkable microorganisms. About two billion years ago, their distant free-living ancestors hooked up with a truly foreign lineage of archaebacteria and started a genomic merger that led to the most successful coevolved mutualism on the planet: the eukaryotic cell. Along the way, evolving mitochondria lost a lot of genomic baggage, entrusted their emerging hosts with their own replication, sorted out genomic conflicts by following maternal inheritance, and have mostly abstained from sex and recombination. What mitochondria did retain was a subset of genes that encode critical components of the electron transport chain and ATP synthesis enzymes that carry out oxidative phosphorylation. Because mitochondria house the biochemical machinery that requires us to breathe oxygen, it was first assumed that mitochondrial genes would show very slow rates of molecular evolution. So it was big news almost 30 years ago when mitochondrial DNA (mtDNA) evolution was observed to be quite rapid [1]. How could the genes for a highly conserved and critical function sustain the consequences of high mutation pressure and permit rapid rates of nucleotide substitution between species? Without the benefits of recombination, where offspring can carry fewer mutations than either parent, mutations should accumulate in mitochondrial genomes through the random loss of less-mutated genomes, a process referred to as Muller's ratchet [2,3]. How have mitochondria avoided a mutational meltdown, or at least significant declines in fitness?
Here is a jaw droppingly beautiful 3D animation of what Mitochindria look like in action.
[more inside]
posted by Blasdelb
on Oct 19, 2012 -
37 comments
Provirophages and transpovirons as the diverse mobilome of giant viruses Abstract: A distinct class of infectious agents, the virophages1 that infect giant viruses of the Mimiviridae family, has been recently described. Here we report the simultaneous discovery of a giant virus of Acanthamoeba polyphaga (Lentille virus) that contains an integrated genome2 of a virophage (Sputnik 2), and a member of a previously unknown class of mobile genetic elements3, the transpovirons4. The transpovirons are linear DNA elements of ∼7 kb [kilobases]5 that encompass six to eight protein-coding genes, two of which are homologous6 to virophage genes. Fluorescence7 in situ hybridization8 showed that the free form of the transpoviron replicates within the giant virus factory and accumulates in high copy numbers inside giant virus particles, Sputnik 2 particles, and amoeba cytoplasm. Analysis of deep-sequencing data showed that the virophage and the transpoviron can integrate9 in nearly any place in the chromosome of the giant virus host and that, although less frequently, the transpoviron can also be linked to the virophage chromosome. In addition, integrated fragments of transpoviron DNA were detected in several giant virus and Sputnik genomes. Analysis of 19 Mimivirus strains revealed three distinct transpovirons associated with three subgroups of Mimiviruses. The virophage, the transpoviron, and the previously identified self-splicing introns10 and inteins11 constitute the complex, interconnected mobilome12 of the giant viruses and are likely to substantially contribute to interviral gene transfer.
[
Full Text PDF] and
two explanations in English [more inside]
posted by Blasdelb
on Oct 16, 2012 -
28 comments
Since mid-2011, a substantial rise in pertussis [Whooping Cough] cases has been reported in the state of Washington. In response to this increase, the Washington State Secretary of Health declared a pertussis epidemic on April 3, 2012. By June 16, the reported number of cases in Washington in 2012 had reached 2,520 (37.5 cases per 100,000 residents), a 1,300% increase compared with the same period in 2011 and the highest number of cases reported in any year since 1942 [Make sure you don't miss Figure 1]. Commentators are already drawing corellations with the fact that
Washington State leads the nation in vaccine non-compliance,
Washington State's recent cutbacks in public health funding, and
increases in the number of uninsured (PDF).
[more inside]
posted by Blasdelb
on Sep 27, 2012 -
111 comments
Improving Peptides:
Small firms develop better peptide drug candidates to expand this pharmaceutical class and attract big pharma partners
posted by Blasdelb
on Jun 2, 2011 -
7 comments
