SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Source

164

In order to survive, animals must quickly and accurately locate prey, predators, and conspecifics using the signals they generate. The signal source location can be estimated using multiple detectors and the inverse relationship between the received signal intensity (RSI) and the distance, but difficulty of the source localization increases if there is an additional dependence on the orientation of a signal source. In such cases, the signal source could be approximated as an ideal dipole for simplification. Based on a theoretical model, the RSI can be directly predicted from a known dipole location; but estimating a dipole location from RSIs has no direct analytical solution. Here, we propose an efficient solution to the dipole localization problem by using a lookup table (LUT) to store RSIs predicted by our theoretically derived dipole model at many possible dipole positions and orientations. For a given set of RSIs measured at multiple detectors, our algorithm found a dipole location having the closest matching normalized RSIs from the LUT, and further refined the location at higher resolution. Studying the natural behavior of weakly electric fish (WEF) requires efficiently computing their location and the temporal pattern of their electric signals over extended periods. Our dipole localization method was successfully applied to track single or multiple freely swimming WEF in shallow water in real-time, as each fish could be closely approximated by an ideal current dipole in two dimensions. Our optimized search algorithm found the animal’s positions, orientations, and tail-bending angles quickly and accurately under various conditions, without the need for calibrating individual-specific parameters. Our dipole localization method is directly applicable to studying the role of active sensing during spatial navigation, or social interactions between multiple WEF. Furthermore, our method could be extended to other application areas involving dipole source localization.

Concepts: Scientific method, Predation, Dimension, Signal, The Signal, Source, Electric eel, Electric fish

88

To (1) estimate the proportion of nonmedical users of prescription opioids (i.e., used prescription opioids in the past year without a doctor’s orders) who used leftover medications from their own previous prescriptions; (2) assess substance use behaviors as a function of diversion source; and (3) identify the sources for these prescribed opioids.

Concepts: Prescription drug, High school, Source code, Medical prescription, Source, High School Musical, Twelfth grade

61

The development of new antimalarial compounds remains a pivotal part of the strategy for malaria elimination. Recent large-scale phenotypic screens have provided a wealth of potential starting points for hit-to-lead campaigns. One such public set is explored, employing an open source research mechanism in which all data and ideas were shared in real time, anyone was able to participate, and patents were not sought. One chemical subseries was found to exhibit oral activity but contained a labile ester that could not be replaced without loss of activity, and the original hit exhibited remarkable sensitivity to minor structural change. A second subseries displayed high potency, including activity within gametocyte and liver stage assays, but at the cost of low solubility. As an open source research project, unexplored avenues are clearly identified and may be explored further by the community; new findings may be cumulatively added to the present work.

Concepts: Present, Time, Pharmacology, Solubility, Research, Source, Open source, Open research

46

Ancient DNA makes it possible to observe natural selection directly by analysing samples from populations before, during and after adaptation events. Here we report a genome-wide scan for selection using ancient DNA, capitalizing on the largest ancient DNA data set yet assembled: 230 West Eurasians who lived between 6500 and 300 bc, including 163 with newly reported data. The new samples include, to our knowledge, the first genome-wide ancient DNA from Anatolian Neolithic farmers, whose genetic material we obtained by extracting from petrous bones, and who we show were members of the population that was the source of Europe’s first farmers. We also report a transect of the steppe region in Samara between 5600 and 300 bc, which allows us to identify admixture into the steppe from at least two external sources. We detect selection at loci associated with diet, pigmentation and immunity, and two independent episodes of selection on height.

Concepts: DNA, Gene, Genetics, Natural selection, Biology, Population genetics, Source, Charles Darwin

35

Observation of terrestrial mammals suggests that they can follow the wind (anemotaxis), but the sensory cues underlying this ability have not been studied. We identify a significant contribution to anemotaxis mediated by whiskers (vibrissae), a modality previously studied only in the context of direct tactile contact. Five rats trained on a five-alternative forced-choice airflow localization task exhibited significant performance decrements after vibrissal removal. In contrast, vibrissal removal did not disrupt the performance of control animals trained to localize a light source. The performance decrement of individual rats was related to their airspeed threshold for successful localization: animals that found the task more challenging relied more on the vibrissae for localization cues. Following vibrissal removal, the rats deviated more from the straight-line path to the air source, choosing sources farther from the correct location. Our results indicate that rats can perform anemotaxis and that whiskers greatly facilitate this ability. Because air currents carry information about both odor content and location, these findings are discussed in terms of the adaptive significance of the interaction between sniffing and whisking in rodents.

Concepts: Mammal, Sensory system, Performance, Rodent, Wind, Source, Localization

32

Whether spanking is helpful or harmful to children continues to be the source of considerable debate among both researchers and the public. This article addresses 2 persistent issues, namely whether effect sizes for spanking are distinct from those for physical abuse, and whether effect sizes for spanking are robust to study design differences. Meta-analyses focused specifically on spanking were conducted on a total of 111 unique effect sizes representing 160,927 children. Thirteen of 17 mean effect sizes were significantly different from zero and all indicated a link between spanking and increased risk for detrimental child outcomes. Effect sizes did not substantially differ between spanking and physical abuse or by study design characteristics. (PsycINFO Database Record

Concepts: Medical statistics, Child, Effect size, Meta-analysis, Abuse, Source, Gene V. Glass

29

Media coverage of medical research influences the views and behaviours of clinicians, scientists and members of the public. We examined how frequently commenters in news stories about medical research have relevant expertise and have academic and financial conflicts, how often such conflicts are reported and whether there are associations between the conflicts and the disposition of the comments toward the findings of the source research.

Concepts: Source

29

When the director-general of the World Health Organization (WHO) declared that the recently reported clusters of microcephaly and other neurologic disorders represent a Public Health Emergency of International Concern (PHEIC), she called for increased research into their cause, including the question of whether the Zika virus is the source of the problem.(1) The declaration provides an opportunity to step up the pace of research in order to find the answer to some important questions more quickly. It could not only facilitate the accumulation of knowledge about the relationship between the Zika virus and microcephaly, but also accelerate the study of . . .

Concepts: Public health, Question, World, Answer, World Health Organization, Source, Charlton Comics, The Declaration

29

Fish currently supplies only 40% of the eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) required to allow all individuals globally to meet the minimum intake recommendation of 500 mg/d. Therefore, alternative sustainable sources are needed.

Concepts: Omega-3 fatty acid, Seed, Source code, Eicosapentaenoic acid, Docosahexaenoic acid, Seafood, Source, Fish oil

28

Tiotropium, a long-acting anticholinergic, is delivered via HandiHaler(®) or via Respimat(®). RCTs suggest that use of Tiotropium Respimat(®) increases the risk of dying. We compared the risk of mortality between tiotropium Respimat(®) vs. HandiHaler(®).Within the Integrated Primary Care Information database, we defined a source population of patients, ≥40 years, with at least 1 year of follow-up. Based on prescription data, we defined episodes of tiotropium use (Respimat(®) or Handihaler(®)). The risk of mortality, within these episodes, was calculated using a Cox proportional hazard regression analysis.From the source population, 11287 patients provided 24522 episodes of tiotropium use. 496 patients died while being exposed to Handihaler(®) or Respimat(®). Use of Respimat(®) was associated with almost 30% increased risk of dying (HRadj 1.27, 95% CI 1.03-1.57) with the highest risk for cardiovascular/cerebrovascular death (HRadj 1.56, 95% CI 1.08-2.25). The risk was higher in patients with co-existing cardiovascular disease (HRadj 1.36, 95% CI 1.07-1.73) than in patients without (HRadj 1.02, 95% CI 0.61-1.71).Use of tiotropium Respimat(®) was associated with an almost 30% increase of mortality compared to Handihaler(®) and the association was the strongest for cardiovascular/cerebrovascular death. It is unclear whether this association is causal or due to residual confounding by COPD severity.

Concepts: Disease, Death, Demography, Cardiovascular disease, Confounding, Tiotropium, The Strongest, Source