326 research outputs found

    Sensitivity of a cavityless optomechanical system

    Full text link
    We study the possibility of revealing a weak coherent force by using a pendular mirror as a probe, and coupling this to a radiation field, which acts as the meter, in a cavityless configuration. We determine the sensitivity of such a scheme and show that the use of an entangled meter state greatly improves the ultimate detection limit. We also compare this scheme with that involving an optical cavity.Comment: 4 pages, RevTex file, 2 eps figures, provisionally accepted by Phys. Rev.

    Searching for answers in an uncertain world: meaning threats lead to increased working memory capacity

    Get PDF
    The Meaning Maintenance Model posits that individuals seek to resolve uncertainty by searching for patterns in the environment, yet little is known about how this is accomplished. Four studies investigated whether uncertainty has an effect on people’s cognitive functioning. In particular, we investigated whether meaning threats lead to increased working memory capacity. In each study, we exposed participants to either an uncertain stimulus used to threaten meaning in past studies, or a control stimulus. Participants then completed a working memory measure, where they either had to recall lists of words (Studies 1, 2), or strings of digits (Studies 3, 4). We used both a frequentist approach and Bayesian analysis to evaluate our findings. Across the four studies, we find a small but consistent effect, where participants in the meaning threat condition show improved performance on the working memory tasks. Overall, our findings were consistent with the hypothesis that working memory capacity increases when people experience a meaning threat, which may help to explain improved pattern recognition. Additionally, our results highlight the value of using a Bayesian analytic approach, particularly when studying phenomena with high variance

    Wavefront invasion for a chemotaxis model of Multiple Sclerosis

    Get PDF
    In this work we study wavefront propagation for a chemotaxis reaction-diffusion system describing the demyelination in Multiple Sclerosis. Through a weakly non linear analysis, we obtain the Ginzburg–Landau equation governing the evolution of the amplitude of the pattern. We validate the analytical findings through numerical simulations. We show the existence of traveling wavefronts connecting two different steady solutions of the equations. The proposed model reproduces the progression of the disease as a wave: for values of the chemotactic parameter below threshold, the wave leaves behind a homogeneous plaque of apoptotic oligodendrocytes. For values of the chemotactic coefficient above threshold, the model reproduces the formation of propagating concentric rings of demyelinated zones, typical of Baló’s sclerosis

    Exercise professional education, qualifications, and certifications: a content analysis of job postings in the United States

    Get PDF
    IntroductionGrowth in the field of clinical exercise science and the potential impacts on overall health and wellbeing have driven the need for qualified, clinically trained, exercise professionals. And yet, it is not well understood what specific credentials employers are seeking when hiring exercise professionals.PurposeThe purpose of the study was to examine the qualification requirements for professionals seeking employment in exercise science, exercise physiology, kinesiology or equivalent fields.MethodsSearch platforms Indeed.com and USAJobs.gov were examined within a two week period in 2022. Search terms included “Exercise Physiology”, “Exercise Science”, “Exercise Professional”, “Exercise Prescription”, “Exercise Specialist”, and “Kinesiology”.ResultsA total of n = 739 jobs were retrieved and n = 615 jobs were included: Exercise Science (n = 227), Kinesiology (n = 210), Exercise Physiology (n = 91), Exercise specialist (n = 53), and Exercise prescription (n = 32). Over 70% of the jobs analyzed required a bachelor's degree with the remainder requiring various levels of education. The primary certification required was personal trainer (n = 94), followed by strength and conditioning specialist (n = 33), clinical exercise physiologist (n = 26), group exercise (n = 17), exercise specialist (n = 10), and exercise physiologist (n = 5). Four job focus areas were determined: academic teaching and research, general fitness and worksite wellness, athletic performance and rehabilitation, clinical exercise specialist all with varying levels of degree and certification requirements.DiscussionJob postings related to exercise related professions are varied across the United States with wide-ranging education, credentialing and certification requirements. These findings indicate the timely need for outreach to employers to highlight changing credentialing requirements due to evolving accreditation standards

    Exercise professional education, qualifications, and certifications: A content analysis of job postings in the United States

    Get PDF
    Introduction: Growth in the field of clinical exercise science and the potential impacts on overall health and wellbeing have driven the need for qualified, clinically trained, exercise professionals. And yet, it is not well understood what specific credentials employers are seeking when hiring exercise professionals. Purpose: The purpose of the study was to examine the qualification requirements for professionals seeking employment in exercise science, exercise physiology, kinesiology or equivalent fields. Methods: Search platforms Indeed.com and USAJobs.gov were examined within a two week period in 2022. Search terms included “Exercise Physiology”, “Exercise Science”, “Exercise Professional”, “Exercise Prescription”, “Exercise Specialist”, and “Kinesiology”. Results: A total of n = 739 jobs were retrieved and n = 615 jobs were included: Exercise Science (n = 227), Kinesiology (n = 210), Exercise Physiology (n = 91), Exercise specialist (n = 53), and Exercise prescription (n = 32). Over 70% of the jobs analyzed required a bachelor\u27s degree with the remainder requiring various levels of education. The primary certification required was personal trainer (n = 94), followed by strength and conditioning specialist (n = 33), clinical exercise physiologist (n = 26), group exercise (n = 17), exercise specialist (n = 10), and exercise physiologist (n = 5). Four job focus areas were determined: academic teaching and research, general fitness and worksite wellness, athletic performance and rehabilitation, clinical exercise specialist all with varying levels of degree and certification requirements. Discussion: Job postings related to exercise related professions are varied across the United States with wide-ranging education, credentialing and certification requirements. These findings indicate the timely need for outreach to employers to highlight changing credentialing requirements due to evolving accreditation standards

    Both selective and neutral processes drive GC content evolution in the human genome

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Mammalian genomes consist of regions differing in GC content, referred to as isochores or GC-content domains. The scientific debate is still open as to whether such compositional heterogeneity is a selected or neutral trait.</p> <p>Results</p> <p>Here we analyze SNP allele frequencies, retrotransposon insertion polymorphisms (RIPs), as well as fixed substitutions accumulated in the human lineage since its divergence from chimpanzee to indicate that biased gene conversion (BGC) has been playing a role in within-genome GC content variation. Yet, a distinct contribution to GC content evolution is accounted for by a selective process. Accordingly, we searched for independent evidences that GC content distribution does not conform to neutral expectations. Indeed, after correcting for possible biases, we show that intron GC content and size display isochore-specific correlations.</p> <p>Conclusion</p> <p>We consider that the more parsimonious explanation for our results is that GC content is subjected to the action of both weak selection and BGC in the human genome with features such as nucleosome positioning or chromatin conformation possibly representing the final target of selective processes. This view might reconcile previous contrasting findings and add some theoretical background to recent evidences suggesting that GC content domains display different behaviors with respect to highly regulated biological processes such as developmentally-stage related gene expression and programmed replication timing during neural stem cell differentiation.</p

    Distorted Copulas: Constructions and Tail Dependence

    Get PDF
    Given a copula C, we examine under which conditions on an order isomorphism ψ of [0, 1] the distortion C ψ: [0, 1]2 → [0, 1], C ψ(x, y) = ψ{C[ψ−1(x), ψ−1(y)]} is again a copula. In particular, when the copula C is totally positive of order 2, we give a sufficient condition on ψ that ensures that any distortion of C by means of ψ is again a copula. The presented results allow us to introduce in a more flexible way families of copulas exhibiting different behavior in the tails

    A complex selection signature at the human AVPR1B gene

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>The vasopressin receptor type 1b (<it>AVPR1B</it>) is mainly expressed by pituitary corticotropes and it mediates the stimulatory effects of AVP on ACTH release; common <it>AVPR1B </it>haplotypes have been involved in mood and anxiety disorders in humans, while rodents lacking a functional receptor gene display behavioral defects and altered stress responses.</p> <p>Results</p> <p>Here we have analyzed the two exons of the gene and the data we present suggest that <it>AVPR1B </it>has been subjected to natural selection in humans. In particular, analysis of exon 2 strongly suggests the action of balancing selection in African populations and Europeans: the region displays high nucleotide diversity, an excess of intermediate-frequency alleles, a higher level of within-species diversity compared to interspecific divergence and a genealogy with common haplotypes separated by deep branches. This relatively unambiguous situation coexists with unusual features across exon 1, raising the possibility that a nonsynonymous variant (Gly191Arg) in this region has been subjected to directional selection.</p> <p>Conclusion</p> <p>Although the underlying selective pressure(s) remains to be identified, we consider this to be among the first documented examples of a gene involved in mood disorders and subjected to natural selection in humans; this observation might add support to the long-debated idea that depression/low mood might have played an adaptive role during human evolution.</p
    corecore