Continuous-wave room-temperature diamond maser

The maser, older sibling of the laser, has been confined to relative obscurity due to its reliance on cryogenic refrigeration and high-vacuum systems. Despite this it has found application in deep-space communications and radio astronomy due to its unparalleled performance as a low-noise amplifier and oscillator. The recent demonstration of a room-temperature solid- state maser exploiting photo-excited triplet states in organic pentacene molecules paves the way for a new class of maser that could find applications in medicine, security and sensing, taking advantage of its sensitivity and low noise. However, to date, only pulsed operation has been observed in this system. Furthermore, organic maser molecules have poor thermal and mechanical properties, and their triplet sub-level decay rates make continuous emission challenging: alternative materials are therefore required. Therefore, inorganic materials containing spin-defects such as diamond and silicon carbide have been proposed. Here we report a continuous-wave (CW) room-temperature maser oscillator using optically pumped charged nitrogen-vacancy (NV) defect centres in diamond. This demonstration unlocks the potential of room-temperature solid-state masers for use in a new generation of microwave devices.Comment: 7 pages, 4 figure

First observation of Dorylus ant feeding in Budongo chimpanzees supports absence of stick-tool culture

The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement no 283871.The use of stick- or probe-tools is a chimpanzee universal, recorded in all long-term study populations across Africa, except one: Budongo, Uganda. Here, after 25-years of observation, stick-tool use remains absent under both natural circumstances and strong experimental scaffolding. Instead, the chimpanzees employ a rich repertoire of leaf-tools for a variety of dietary and hygiene tasks. One use of stick-tools in other communities is in feeding on the aggressive Dorylus ‘army-ant’ species, consumed by chimpanzees at all long-term study sites outside of mid-Western Uganda. Here we report the first observation of army-ant feeding in Budongo, in which individuals from the Waibira chimpanzee community employed detached leaves to feed on a ground swarm. We describe the behaviour and discuss whether or not it can be considered tool-use, together with its implication for the absence of stick-tool ‘culture’ in Budongo chimpanzees.Publisher PDFPeer reviewe

Polypharmacy among anabolic-androgenic steroid users: A descriptive metasynthesis

Background: As far as we are aware, no previous systematic review and synthesis of the qualitative/descriptive literature on polypharmacy in anabolic-androgenic steroid(s) (AAS) users has been published. Method: We systematically reviewed and synthesized qualitative/descriptive literature gathered from searches in electronic databases and by inspecting reference lists of relevant literature to investigate AAS users' polypharmacy. We adhered to the recommendations of the UK Economic and Social Research Council's qualitative research synthesis manual and the PRISMA guidelines. Results: A total of 50 studies published between 1985 and 2014 were included in the analysis. Studies originated from 10 countries although most originated from United States (n = 22), followed by Sweden (n = 7), England only (n = 5), and the United Kingdom (n = 4). It was evident that prior to their debut, AAS users often used other licit and illicit substances. The main ancillary/supplementary substances used were alcohol, and cannabis/cannabinoids followed by cocaine, growth hormone, and human chorionic gonadotropin (hCG), amphetamine/meth, clenbuterol, ephedra/ephedrine, insulin, and thyroxine. Other popular substance classes were analgesics/opioids, dietary/nutritional supplements, and diuretics. Our classification of the various substances used by AAS users resulted in 13 main groups. These non-AAS substances were used mainly to enhance the effects of AAS, combat the side effects of AAS, and for recreational or relaxation purposes, as well as sexual enhancement. Conclusions: Our findings corroborate previous suggestions of associations between AAS use and the use of other licit and illicit substances. Efforts must be intensified to combat the debilitating effects of AAS-associated polypharmacy

The political economy of the disability insurance: theory and evidence of gubernatorial learning

Abstract The dramatic rise in the disability insurance (DI) rolls in the last 20 years has been the subject of much controversy. While the relationship between DI and labor force participation has been the subject of a growing literature, the mechanism of this transition from employment to DI remains unclear. We hypothesize that one mechanism is the state-level administration of the program which creates a classic principal-agent problem. We analyze the conflict of interests for Disability Determination Services agencies between Social Security Administration (SSA) standards and state gubernatorial political interests interacted with the increased demand for disability insurance as an alternative for low-skilled employment during the period of 1982 to 2013. We find evidence that multi-term governors allow a greater fraction of applicants than do first-term governors, but only up to year 2000, when allowance rates started to decrease over time. We develop a model that illustrates how these differences can be due to the type of monitoring conducted by the SSA. We provide additional evidence supporting this hypothesis analyzing how the effects interact with economic and political constraints. JEL codes H55, I18, I38, G22</jats:p

DSYB catalyses the key step of dimethylsulfoniopropionate biosynthesis in many phytoplankton

Dimethylsulfoniopropionate (DMSP) is a globally important organosulfur molecule and the major precursor for dimethyl sulfide. These compounds are important info-chemicals, key nutrients for marine microorganisms, and are involved in global sulfur cycling, atmospheric chemistry and cloud formation1,2,3. DMSP production was thought to be confined to eukaryotes, but heterotrophic bacteria can also produce DMSP through the pathway used by most phytoplankton4, and the DsyB enzyme catalysing the key step of this pathway in bacteria was recently identified5. However, eukaryotic phytoplankton probably produce most of Earth’s DMSP, yet no DMSP biosynthesis genes have been identified in any such organisms. Here we identify functional dsyB homologues, termed DSYB, in many phytoplankton and corals. DSYB is a methylthiohydroxybutryate methyltransferase enzyme localized in the chloroplasts and mitochondria of the haptophyte Prymnesium parvum, and stable isotope tracking experiments support these organelles as sites of DMSP synthesis. DSYB transcription levels increased with DMSP concentrations in different phytoplankton and were indicative of intracellular DMSP. Identification of the eukaryotic DSYB sequences, along with bacterial dsyB, provides the first molecular tools to predict the relative contributions of eukaryotes and prokaryotes to global DMSP production. Furthermore, evolutionary analysis suggests that eukaryotic DSYB originated in bacteria and was passed to eukaryotes early in their evolution

Anatomy of terminal moraine segments and implied lake stability on Ngozumpa Glacier, Nepal, from electrical resistivity tomography (ERT)

This research was supported financially by the European Commission FP7-MC-IEF (PIEF-GA-2012-330805), the University Centre in Svalbard (UNIS), National Geographic Society GRANT #W135-10.Moraine-dammed lakes at debris-covered glaciers are becoming increasingly common and pose significant outburst flood hazards if the dam is breached. While moraine subsurface structure and internal processes are likely to influence dam stability, only few sites have so far been investigated. We conducted electrical resistivity tomography (ERT) surveys at two sites on the terminal moraine complex of the Ngozumpa Glacier, Nepal, to aid assessment of future terminus stability. The resistivity signature of glacier ice at the site (100-15 kΩ m) is more consistent with values measured from cold glacier ice and while this may be feasible, uncertainties in the data inversion introduce ambiguity to this thermal interpretation. However, the ERT data does provide a significant improvement to our knowledge of the subsurface characteristics at these sites, clearly showing the presence (or absence) of glacier ice. Our interpretation is that of a highly complex latero-terminal moraine, resulting from interaction between previous glacier advance, recession and outburst flooding. If the base-level Spillway Lake continues to expand to a fully formed moraine-dammed glacial lake, the degradation of the ice core could have implications for glacial lake outburst risk.Publisher PDFPeer reviewe

A systematic experimental neuropsychological investigation of the functional integrity of working memory circuits in major depression

Verbal and visuospatial working memory (WM) impairment is a well-documented finding in psychiatric patients suffering from major psychoses such as schizophrenia or bipolar affective disorder. However, in major depression (MDD) the literature on the presence and the extent of WM deficits is inconsistent. The use of a multitude of different WM tasks most of which lack process-specificity may have contributed to these inconsistencies. Eighteen MDD patients and 18 healthy controls matched with regard to age, gender and education were tested using process- and circuit-specific WM tasks for which clear brain-behaviour relationships had been established in prior functional neuroimaging studies. Patients suffering from acute MDD showed a selective impairment in articulatory rehearsal of verbal information in working memory. By contrast, visuospatial WM was unimpaired in this sample. There were no significant correlations between symptom severity and WM performance. These data indicate a dysfunction of a specific verbal WM system in acutely ill patients with MDD. As the observed functional deficit did not correlate with different symptom scores, further, longitudinal studies are required to clarify whether and how this deficit is related to illness acuity and clinical state of MDD patients

Cellular dissection of psoriasis for transcriptome analyses and the post-GWAS era

Abstract Background Genome-scale studies of psoriasis have been used to identify genes of potential relevance to disease mechanisms. For many identified genes, however, the cell type mediating disease activity is uncertain, which has limited our ability to design gene functional studies based on genomic findings. Methods We identified differentially expressed genes (DEGs) with altered expression in psoriasis lesions (n = 216 patients), as well as candidate genes near susceptibility loci from psoriasis GWAS studies. These gene sets were characterized based upon their expression across 10 cell types present in psoriasis lesions. Susceptibility-associated variation at intergenic (non-coding) loci was evaluated to identify sites of allele-specific transcription factor binding. Results Half of DEGs showed highest expression in skin cells, although the dominant cell type differed between psoriasis-increased DEGs (keratinocytes, 35%) and psoriasis-decreased DEGs (fibroblasts, 33%). In contrast, psoriasis GWAS candidates tended to have highest expression in immune cells (71%), with a significant fraction showing maximal expression in neutrophils (24%, P < 0.001). By identifying candidate cell types for genes near susceptibility loci, we could identify and prioritize SNPs at which susceptibility variants are predicted to influence transcription factor binding. This led to the identification of potentially causal (non-coding) SNPs for which susceptibility variants influence binding of AP-1, NF-κB, IRF1, STAT3 and STAT4. Conclusions These findings underscore the role of innate immunity in psoriasis and highlight neutrophils as a cell type linked with pathogenetic mechanisms. Assignment of candidate cell types to genes emerging from GWAS studies provides a first step towards functional analysis, and we have proposed an approach for generating hypotheses to explain GWAS hits at intergenic loci.http://deepblue.lib.umich.edu/bitstream/2027.42/109537/1/12920_2013_Article_485.pd

Diagnosis-specific effect of familial loading on verbal working memory in schizophrenia

Working memory disturbances are a frequently replicated finding in schizophrenia and less consistent also in schizoaffective disorder. Working memory dysfunctions have been shown to be heritable and have been proposed to represent a promising endophenotype of schizophrenic psychoses. In the present study, we investigated the effects of familial loading on performance rates in circuit-specific verbal and visuospatial working memory tasks in matched samples of schizophrenic patients (from multiply affected or uniaffected families), schizoaffective patients (from multiply affected or uniaffected families), and healthy subjects. We found a significant interaction effect between familial loading and diagnosis in terms of a diagnosis-specific detrimental effect of familial loading on the performance of schizophrenic (but not schizoaffective) patients in the articulatory rehearsal task. This finding of a circuit-specific verbal working memory deficit in schizophrenic patients with additional familial loading is consistent with prior studies, which provided evidence for the existence of specific subgroups of schizophrenic patients with selective working memory impairments and for diagnosis-specific dysfunctions of the articulatory rehearsal mechanism in schizophrenic, but not in schizoaffective patients. Together, these findings suggest that the genetic risk for (a subtype of) schizophrenia may be associated with dysfunctions of the brain system, which underlies the articulatory rehearsal mechanism, the probably phylogenetically youngest part of human working memory

Representation of cognitive reappraisal goals in frontal gamma oscillations

Recently, numerous efforts have been made to understand the neural mechanisms underlying cognitive regulation of emotion, such as cognitive reappraisal. Many studies have reported that cognitive control of emotion induces increases in neural activity of the control system, including the prefrontal cortex and the dorsal anterior cingulate cortex, and increases or decreases (depending upon the regulation goal) in neural activity of the appraisal system, including the amygdala and the insula. It has been hypothesized that information about regulation goals needs to be processed through interactions between the control and appraisal systems in order to support cognitive reappraisal. However, how this information is represented in the dynamics of cortical activity remains largely unknown. To address this, we investigated temporal changes in gamma band activity (35-55 Hz) in human electroencephalograms during a cognitive reappraisal task that was comprised of three reappraisal goals: To decease, maintain, or increase emotional responses modulated by affect-laden pictures. We examined how the characteristics of gamma oscillations, such as spectral power and large-scale phase synchronization, represented cognitive reappraisal goals. We found that left frontal gamma power decreased, was sustained, or increased when the participants suppressed, maintained, or amplified their emotions, respectively. This change in left frontal gamma power appeared during an interval of 1926 to 2453 ms after stimulus onset. We also found that the number of phase-synchronized pairs of gamma oscillations over the entire brain increased when participants regulated their emotions compared to when they maintained their emotions. These results suggest that left frontal gamma power may reflect cortical representation of emotional states modulated by cognitive reappraisal goals and gamma phase synchronization across whole brain regions may reflect emotional regulatory efforts to achieve these goals. Our study may provide the basis for an electroencephalogram-based neurofeedback system for the cognitive regulation of emotion.open0