Exoplanet atmospheres with EChO: spectral retrievals using EChOSim

We demonstrate the effectiveness of the Exoplanet Characterisation Observatory mission concept for constraining the atmospheric properties of hot and warm gas giants and super Earths. Synthetic primary and secondary transit spectra for a range of planets are passed through EChOSim (Waldmann & Pascale 2014) to obtain the expected level of noise for different observational scenarios; these are then used as inputs for the NEMESIS atmospheric retrieval code and the retrieved atmospheric properties (temperature structure, composition and cloud properties) compared with the known input values, following the method of Barstow et al. (2013a). To correctly retrieve the temperature structure and composition of the atmosphere to within 2 {\sigma}, we find that we require: a single transit or eclipse of a hot Jupiter orbiting a sun-like (G2) star at 35 pc to constrain the terminator and dayside atmospheres; 20 transits or eclipses of a warm Jupiter orbiting a similar star; 10 transits/eclipses of a hot Neptune orbiting an M dwarf at 6 pc; and 30 transits or eclipses of a GJ1214b-like planet.Comment: 13 pages, 15 figures, 1 table. Accepted by Experimental Astronomy. The final publication will shortly be available at Springer via http://dx.doi.org/10.1007/s10686-014-9397-

Challenges to Studying Illicit Drug Users

PurposeThroughout the world, illicit drug use continues to pose a significant risk to public health. The opioid crisis in North America, the diversion of the prescription drug tramadol throughout Africa, and the increasing supply of methamphetamines in East and South Asia all contribute to increasing risks to individual and societal health. Furthermore, the violation of human rights in efforts to enforce prohibitionist values poses significant threats to many individuals worldwide. With these evolving situations, it is imperative that researchers direct their attention to the various populations of illicit drug users. However, the inclusion of illicit drug users, often considered a vulnerable population, as participants in research studies presents several increased risks that must be addressed in study protocols. Researchers are required to provide â additional safeguardsâ to all study protocols involving illicit drug users, but there is often substantial variability and inconsistency in how these safeguards are applied. Additional safeguards can be timely, costly, and unduly burdensome for researchers, ethical review boards, and research participants.ApproachThrough synthesis of the current literature, this article addresses the barriers to studying illicit drug users and the methods researchers can utilize to minimize risk. A case study is provided to illustrate the high level of scrutiny of study protocols involving the participation of illicit drug users and the effect of such scrutiny on recruitment of participants. The article concludes with a discussion of the effects of the current political climate on the recruitment of illicit drug users in research.ConclusionsIndividuals who participate in criminal or illegal behaviors such as illicit drug use, prostitution, illegal entry into a country, and human trafficking are susceptible to multiple physical, mental, and social health risks, as well as criminal prosecution. The importance of research on the health of marginalized populations cannot be overstated. This work must continue, and at the same time, we must continue to protect these individuals to the best of our ability through diligent attention to sound research methods.Clinical RelevanceThe use of illicit drugs continues to pose a substantial threat to global health. Individuals who use illicit drugs are susceptible to multiple physical, mental, and social health risks, as well as criminal prosecution. It is imperative that researchers study these vulnerable populations in order to develop interventions to minimize individual and societal harm. There are several barriers to the study of illicit drug users that must be addressed through rigorous methodology and the addition of safeguards.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150546/1/jnu12486.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150546/2/jnu12486_am.pd

A Turtle Population Study in an Isolated Urban Wetland Complex in Ontario Reveals a Few Surprises

We report on the results of the first mark–recapture survey of freshwater turtles in an isolated urban wetland complex in one of Canada’s fastest growing municipalities. Although we found turtles in every surveyed wetland, the density and assemblage of turtles in smaller wetlands were significantly different than in larger wetland bodies. We also documented two species of turtles that were thought to be absent from this wetland complex, the Northern Map turtle and Eastern Musk turtle. We noted that a wetland that was bisected by a high-traffic road showed a male-skewed sex ratio in the population of Midland Painted turtles but not in the population of Eastern Snapping turtles. As a whole, the sex ratios inside the wetland complex were not skewed. These results reinforce the conclusions of a previous study of a single wetland within this same complex that had found a correlation between road mortality and a male-skewed sex ratio in Midland painted turtles. We discuss population sources and sinks within the complex and the importance of protecting the overland corridors that support the safe turtle movements within this provincially significant wetland complex.York University Librarie

Sickle cell trait and risk of cognitive impairment in African-Americans: The REGARDS cohort

Background: Sickle cell anemia may be associated with cognitive dysfunction, and some complications of sickle cell anemia might affect those with sickle cell trait (SCT), so we hypothesized that SCT is a risk factor for cognitive impairment. Methods: The Reasons for Geographic and Racial Differences in Stroke (REGARDS) study enrolled a national cohort of 30,239 white and black Americans from 2003 to 7, who are followed every 6 months. Baseline and annual global cognitive function testing used the Six-Item Screener (SIS), a validated instrument (scores range 0-6; ≤ 4 indicates cognitive impairment). Participants with baseline cognitive impairment and whites were excluded. Logistic regression was used to calculate the association of SCT with incident cognitive impairment, adjusted for risk factors. Linear mixed models assessed multivariable-adjusted change in test scores on a biennially administered 3-test battery measuring learning, memory, and semantic and phonemic fluency. Findings: Among 7743 participants followed for a median of 7·1 years, 85 of 583 participants with SCT (14·6%) developed incident cognitive impairment compared to 902 of 7160 (12·6%) without SCT. In univariate analysis, the odds ratio (OR) of incident cognitive impairment was 1·18 (95% CI: 0·93, 1·51) for those with SCT vs. those without. Adjustment did not impact the OR. There was no difference in change on 3-test battery scores by SCT status (all p > 0·11). Interpretation: In this prospective cohort study of black Americans, SCT was not associated with incident cognitive impairment or decline in test scores of learning, memory and executive function. Funding: National Institutes of Health, American Society of Hematology

Compensatory Neural Reorganization in Tourette Syndrome

Children with neurological disorders may follow unique developmental trajectories whereby they undergo compensatory neuroplastic changes in brain structure and function that help them gain control over their symptoms [1, 2, 3, 4, 5, 6]. We used behavioral and brain imaging techniques to investigate this conjecture in children with Tourette syndrome (TS). Using a behavioral task that induces high levels of intermanual conflict, we show that individuals with TS exhibit enhanced control of motor output. Then, using structural (diffusion-weighted imaging) brain imaging techniques, we demonstrate widespread differences in the white matter (WM) microstructure of the TS brain that include alterations in the corpus callosum and forceps minor (FM) WM that significantly predict tic severity in TS. Most importantly, we show that task performance for the TS group (but not for controls) is strongly predicted by the WM microstructure of the FM pathways that lead to the prefrontal cortex and by the functional magnetic resonance imaging blood oxygen level-dependent response in prefrontal areas connected by these tracts. These results provide evidence for compensatory brain reorganization that may underlie the increased self-regulation mechanisms that have been hypothesized to bring about the control of tics during adolescence

Spatial Variations in a Condensed Interval between Estuarine and Open-Marine Settings: Holocene Hudson River Estuary and Adjacent Continental Shelf

An interval of stratigraphic condensation extending for 300 km from the fluvially dominated Hudson River estuary to the adjacent continental shelf reveals stratal relationships within an unconformity-related depositional sequence that are commonly difficult to resolve in seismic reflection profiles and outcrop. High-resolution side-scan sonar and bathymetry, more than 100 sediment cores ∼2 m long, and radioisotope (14C, 137Cs) age control show that much of the valley was filled by ca. 3 to 1 ka. The present rate of sediment accumulation averages 1 mm/yr, corresponding with a sea-level rise of ∼1.2 mm/yr relative to local bedrock. Condensation is manifested today by sedimentary bypass in most parts of the estuary and by the trapping of available sediment (1.2–5.6 × 105 t/yr [metric tons]) along narrow reaches and primarily in the vicinity of the estuarine turbidity maximum, a part of the estuary located upstream of the salinity intrusion ∼25 km from the mouth (3.0 × 105 t/yr). Shelf condensation is due to sediment starvation. The condensed interval merges updip with a nascent sequence boundary as the estuary reaches its final filling phase and downdip with the sequence boundary that developed at the Last Glacial Maximum. Delta progradation may take place as available shelf accommodation is filled, but such sediments are expected to be removed once sea level begins to fall. This sedimentation pattern, in which a condensed interval merges with different sequence boundaries, is consistent with the stratigraphic record of the Atlantic margin back to the Paleogene and may be typical of sediment-starved margins

First cryo-scanning electron microscopy images and X-ray microanalyses of mucoromycotinian fine root endophytes in vascular plants

Aims. Arbuscule-producing fine root endophytes (FRE) (previously incorrectly Glomus tenue) were recently placed within subphylum Mucoromycotina; the first report of arbuscules outside subphylum Glomeromycotina. Here, we aimed to estimate nutrient concentrations in plant and fungal structures of FRE and to test the utility of cryo-scanning electron microscopy (cryoSEM) for studying these fungi. Methods. To do so, we used replicated cryoSEM and X-ray microanalysis of heavily colonized roots of Trifolium subterraneum. Results. Intercellular hyphae and hyphae in developed arbuscules were consistently very thin; 1.35 ± 0.03 µm and 0.99 ± 0.03 µm in diameter, respectively (mean ± SE). Several intercellular hyphae were often adjacent to each other forming ‘hyphal ropes’. Developed arbuscules showed higher phosphorus concentrations than senesced arbuscules and non-colonized structures. Senesced arbuscules showed greatly elevated concentrations of calcium and magnesium. Conclusions. While uniformly thin hyphae and hyphal ropes are distinct features of FRE, the morphology of fully developed arbuscules, elevated phosphorus in fungal structures, and accumulation of calcium with loss of structural integrity in senesced arbuscules are similar to glomeromycotinian fungi. Thus, we provide evidence that FRE may respond to similar host-plant signals or that the host plant may employ a similar mechanism of association with FRE and AMF