Thermopower of Interacting GaAs Bilayer Hole Systems in the Reentrant Insulating Phase near ν=1\nu=1

We report thermopower measurements of interacting GaAs bilayer hole systems. When the carrier densities in the two layers are equal, these systems exhibit a reentrant insulating phase near the quantum Hall state at total filling factor $\nu=1$. Our data show that as the temperature is decreased, the thermopower diverges in the insulating phase. This behavior indicates the opening of an energy gap at low temperature, consistent with the formation of a pinned Wigner solid. We extract an energy gap and a Wigner solid melting phase diagram.Comment: to be published in Phys. Rev. Let

The information analysis center concept as developed by the Radiation Shielding Information Center in its computer codes activities

Information analysis center concept and computer codes for calculating radiation transport, and shield design

Cryptic Diversity and Conservation of Gopher Frogs across the Southeastern United States

Identifying cryptic biodiversity is fundamental to evolutionary biology and to conservation efforts. This study investigated range-wide genetic diversity of Gopher Frogs, Lithobates capito, across the southeastern United States coastal plain to determine implications for taxonomy and conservation. We collected data for two mtDNA regions in 21 populations to identify genetic structure across the geographic distribution of the species. Based on population genetic, phylogenetic, and genealogical analyses, we recovered three reciprocally monophyletic mtDNA lineages corresponding to mainland coastal plain populations and two lineages within peninsular Florida. Breakpoints for these lineages did not occur in previously identified hotspots of amphibian phylogeographic breaks and did not follow currently recognized subspecies designations. We recommend these lineages be recognized as separate distinct population segments and be considered separately by the U.S. Fish and Wildlife Service for listing under the Endangered Species Act. Additionally, we propose an evolutionary hotspot for amphibians that deserves further attentio

Auroral signatures of multiple magnetopause reconnection at Saturn

Auroral observations capture the ionospheric response to dynamics of the whole magnetosphere and may provide evidence of the significance of reconnection at Saturn. Bifurcations of the main dayside auroral emission have been related to reconnection at the magnetopause and their surface is suggested to represent the amount of newly opened flux. This work is the first presentation of multiple brightenings of these auroral features based on Cassini ultraviolet auroral observations. In analogy to the terrestrial case, we propose a process, in which a magnetic flux tube reconnects with other flux tubes at multiple sites. This scenario predicts the observed multiple brightenings, it is consistent with subcorotating auroral features which separate from the main emission, and it suggests north-south auroral asymmetries. We demonstrate that the conditions for multiple magnetopause reconnection can be satisfied at Saturn, like at Earth

From START to FINISH : the influence of osmotic stress on the cell cycle

Peer reviewedPublisher PD

Evolution of associative learning in chemical networks

Organisms that can learn about their environment and modify their behaviour appropriately during their lifetime are more likely to survive and reproduce than organisms that do not. While associative learning – the ability to detect correlated features of the environment – has been studied extensively in nervous systems, where the underlying mechanisms are reasonably well understood, mechanisms within single cells that could allow associative learning have received little attention. Here, using in silico evolution of chemical networks, we show that there exists a diversity of remarkably simple and plausible chemical solutions to the associative learning problem, the simplest of which uses only one core chemical reaction. We then asked to what extent a linear combination of chemical concentrations in the network could approximate the ideal Bayesian posterior of an environment given the stimulus history so far? This Bayesian analysis revealed the ’memory traces’ of the chemical network. The implication of this paper is that there is little reason to believe that a lack of suitable phenotypic variation would prevent associative learning from evolving in cell signalling, metabolic, gene regulatory, or a mixture of these networks in cells

Efficacy and Safety of Medicines Targeting Neurotrophic Factors in the Management of Low Back Pain: Protocol for a Systematic Review and Meta-Analysis (Preprint)

BACKGROUND Low back pain (LBP) is the leading cause of years lived with disability worldwide. Most people with LBP receive the diagnosis of nonspecific LBP or sciatica. Medications are commonly prescribed but have limited analgesic effects and are associated with adverse events. A novel treatment approach is to target neurotrophins such as nerve growth factor (NGF) to reduce pain intensity. NGF inhibitors have been tested in some randomized controlled trials (RCTs) in recent years, showing promise for the treatment of chronic LBP; however, their efficacy and safety need to be evaluated to guide regulatory actions. OBJECTIVE The aim of this study is to evaluate the efficacy and safety of medicines targeting neurotrophins in patients with LBP and sciatica. METHODS In this systematic review, we will include published and unpublished records of parallel RCTs and the first phase of crossover RCTs that compare the effects of medicines targeting neurotrophins with any control group. We will search the CENTRAL, MEDLINE, Embase, CINAHL, ClinicalTrials.gov, EU Clinical Trials Register, and WHO International Clinical Registry Platform databases from inception. Pairs of authors will independently screen the records for eligibility, and we will independently extract data in duplicate. We will conduct a quantitative synthesis (meta-analysis) with the studies that report sufficient data and compare the medicines of interest versus placebo. We will use random-effects models and calculate estimates of effects and heterogeneity for each outcome. We will assess the risk of bias for each study using the Cochrane Collaboration tool, and form judgments of confidence in the evidence according to GRADE recommendations. We will use the PRISMA statement to report the findings. We plan to conduct subgroup analyses by condition, type of medication, and time point. We will also assess the impact of a potential new trial on an existing meta-analysis. Data from studies that meet inclusion criteria but cannot be included in the meta-analysis will be reported narratively. RESULTS The protocol was registered on the Open Science Framework on May 19, 2020. As of December 2020, we have identified 1932 records. CONCLUSIONS This systematic review and meta-analysis will assess the evidence for the efficacy and safety of NGF inhibitors for pain in patients with nonspecific LBP and sciatica. The inclusion of new studies and unpublished data may improve the precision of the effect estimates and guide regulatory actions of the medications for LBP and sciatica. CLINICALTRIAL Open Science Framework; https://osf.io/b8adn/ INTERNATIONAL REGISTERED REPORT DERR1-10.2196/22905 </sec

Global response of the upper thermospheric winds to large ion drifts in the Jovian ovals

We use our fully coupled 3‐D Jupiter Thermosphere General Circulation Model (JTGCM) to quantify processes which are responsible for generating neutral winds in Jupiter’s oval thermosphere from 20 µbar to 10−4 nbar self‐consistently with the thermal structure and composition. The heat sources in the JTGCM that drive the global circulation of neutral flow are substantial Joule heating produced in the Jovian ovals by imposing high‐speed anticorotational ion drifts (~3.5 km s−1) and charged particle heating from auroral processes responsible for bright oval emissions. We find that the zonal flow of neutral winds in the auroral ovals of both hemispheres is primarily driven by competition between accelerations resulting from Coriolis forcing and ion drag processes near the ionospheric peak. However, above the ionospheric peak (<0.01 µbar), the acceleration of neutral flow due to pressure gradients is found to be the most effective parameter impacting zonal winds, competing mainly with acceleration due to advection with minor contributions from curvature and Coriolis forces in the southern oval, while in the northern oval it competes alone with considerable Coriolis forcing. The meridional flow of neutral winds in both ovals in the JTGCM is determined by competition between meridional accelerations due to Coriolis forcing and pressure gradients. We find that meridional flow in the lower thermosphere, near the peak of the auroral ionosphere, is poleward, with peak wind speeds of ~0.6 km s−1 and ~0.1 km s−1 in the southern and northern oval, respectively. The corresponding subsiding flow of neutral motion is ~5 m s−1 in the southern oval, while this flow is rising in the northern oval with reduced speed of ~2 m s−1. We also find that the strength of meridional flow in both auroral ovals is gradually weakened and turned equatorward near 0.08 µbar with wind speeds up to ~250 m s−1 (southern oval) and ~75 m s−1 (northern oval). The corresponding neutral motion in this region is upward, with wind speeds up to 4 m s−1 in both ovals.Key PointsUnderlying thermal and dynamical processes of the Jovian thermosphereForcing terms responsible for generating Jupiter’s neutral wind speedsSimulated neutral wind speed is compared with the measured wind speedPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146281/1/jgra52522_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146281/2/jgra52522.pd