1,306 research outputs found

    Enriched functor categories for functor calculus

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    In this paper we present background results in enriched category theory and enriched model category theory necessary for developing model categories of enriched functors suitable for doing functor calculus

    Spectral pattern similarity analysis: Tutorial and application in developmental cognitive neuroscience

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    The human brain encodes information in neural activation patterns. While standard approaches to analyzing neural data focus on brain (de-)activation (e.g., regarding the location, timing, or magnitude of neural responses), multivariate neural pattern similarity analyses target the informational content represented by neural activity. In adults, a number of representational properties have been identified that are linked to cognitive performance, in particular the stability, distinctiveness, and specificity of neural patterns. However, although growing cognitive abilities across childhood suggest advancements in representational quality, developmental studies still rarely utilize information-based pattern similarity approaches, especially in electroencephalography (EEG) research. Here, we provide a comprehensive methodological introduction and step-by-step tutorial for pattern similarity analysis of spectral (frequency-resolved) EEG data including a publicly available pipeline and sample dataset with data from children and adults. We discuss computation of single-subject pattern similarities and their statistical comparison at the within-person to the between-group level as well as the illustration and interpretation of the results. This tutorial targets both novice and more experienced EEG researchers and aims to facilitate the usage of spectral pattern similarity analyses, making these methodologies more readily accessible for (developmental) cognitive neuroscientists

    Bubble formation in ϕ6\phi^6 potential

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    Scalar field theory with an asymmetric potential is studied at zero temperature and high-temperature for ϕ6\phi^6 potential. The equations of motion are solved numerically to obtain O(4) spherical symmetric and O(3) cylindrical symmetric bounce solutions. These solutions control the rates for tunneling from the false vacuum to the true vacuum by bubble formation. The range of validity of the thin-wall approximation (TWA) is investigated. An analytical solution for the bounce is presented, which reproduces the action in the thin-wall as well as the thick-wall limits.Comment: 22 pag

    Navigating the Accounting Academic Job Market and Related Advice

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    Purpose: To disseminate helpful advice to current and future candidates about the accounting academic job market. Methodology/Approach: Literature review, interviews with recently hired faculty members, insights from the author’s experiences as both job candidates and search committee members, and discussions with colleagues. Findings: In this chapter, we discuss the current state of the job market for accounting professors and offer our insights as well as those from a group of recent graduates. It is our recent experience that many rookie candidates pursue initial faculty positions with an incomplete understanding of many aspects of the market, including how the market clears, job expectations, and other issues that we believe are important. While others have adequately addressed the importance of research in the profession and alluded to some aspects of the market, we provide additional useful information about the market and other career aspects in order to assist new graduates in their quests to find fulfilling appointments. Our chapter complements existing literature to form an updated and more complete picture of the market and profession. Practical Implications: This chapter helps prepare candidates for the job market by providing information and advice that complements advice given in Ph.D. programs and the existing literature. Social Implications: Candidates entering the job market will better understand the nuances of the market and can make more informed decisions about the institutions that best meet their needs. Originality/Value of Article: The chapter provides important practical advice for job seekers about the accounting academic job market not available elsewhere

    Effects of different regions of the developing gut on the migration of enteric neural crest-derived cells: A role for Sema3A, but not Sema3F

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    AbstractThe enteric nervous system arises from vagal (caudal hindbrain) and sacral level neural crest-derived cells that migrate into and along the developing gut. Data from previous studies have suggested that (i) there may be gradients along the gut that induce the caudally directed migration of vagal enteric neural precursors (ENPs), (ii) exposure to the caecum might alter the migratory ability of vagal ENPs and (iii) Sema3A might regulate the entry into the hindgut of ENPs derived from sacral neural crest. Using co-cultures we show that there is no detectable gradient of chemoattractive molecules along the pre-caecal gut that specifically promotes the caudally directed migration of vagal ENPs, although vagal ENPs migrate faster caudally than rostrally along explants of hindgut. Exposure to the caecum did not alter the rate at which ENPs colonized explants of hindgut, but it did alter the ability of ENPs to colonize the midgut. The co-cultures also revealed that there is localized expression of a repulsive cue in the distal hindgut, which might delay the entry of sacral ENPs. We show that Sema3A is expressed by the hindgut mesenchyme and its receptor, neuropilin-1, is expressed by migrating ENPs. Furthermore, there is premature entry of sacral ENPs and extrinsic axons into the distal hindgut of fetal mice lacking Sema3A. These data show that Sema3A expressed by the distal hindgut regulates the entry of sacral ENPs and extrinsic axons into the hindgut. ENPs did not express neuropilin-2 and there was no detectable change in the timetable by which ENPs colonize the gut in mice lacking neuropilin-2

    Strongly absorbed quiescent X-ray emission from the X-ray transient XTE J0421+56 (CI Cam) observed with XMM-Newton

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    We have observed the X-ray transient XTE J0421+56 in quiescence with XMM-Newton. The observed spectrum is highly unusual being dominated by an emission feature at ~6.5 keV. The spectrum can be fit using a partially covered power-law and Gaussian line model, in which the emission is almost completely covered (covering fraction of 0.98_{-0.06}^{+0.02}) by neutral material and is strongly absorbed with an N_H of (5_{-2}^{+3}) x 10^{23} atom cm^{-2}. This absorption is local and not interstellar. The Gaussian has a centroid energy of 6.4 +/- 0.1 keV, a width < 0.28 keV and an equivalent width of 940 ^{+650}_{-460} eV. It can be interpreted as fluorescent emission line from iron. Using this model and assuming XTE J0421+56 is at a distance of 5 kpc, its 0.5-10 keV luminosity is 3.5 x 10^{33} erg s^{-1}. The Optical Monitor onboard XMM-Newton indicates a V magnitude of 11.86 +/- 0.03. The spectra of X-ray transients in quiescence are normally modeled using advection dominated accretion flows, power-laws, or by the thermal emission from a neutron star surface. The strongly locally absorbed X-ray emission from XTE J0421+56 is therefore highly unusual and could result from the compact object being embedded within a dense circumstellar wind emitted from the supergiant B[e] companion star. The uncovered and unabsorbed component observed below 5 keV could be due either to X-ray emission from the supergiant B[e] star itself, or to the scattering of high-energy X-ray photons in a wind or ionized corona, such as observed in some low-mass X-ray binary systems.Comment: 8 pages, 4 postscript figures, accepted for publication in Astronomy and Astrophysic

    Descriptions of disordered eating in German psychiatric textbooks, 1803–2017

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    The most common eating disorders (EDs) according to DSM-5 are anorexia nervosa(AN), bulimia nervosa (BN) and binge eating disorder (BED). These disorders havereceived increasing attention in psychiatry due to rising prevalence and high morbidityand mortality. The diagnostic category “anorexia nervosa,” introduced by Ernest-CharlesLasègue and William Gull in 1873, first appears a century later in a German textbook ofpsychiatry, authored by Gerd Huber in 1974. However, disordered eating behavior hasbeen described and discussed in German psychiatric textbooks throughout the past 200years. We reviewed content regarding eating disorder diagnoses but also descriptionsof disordered eating behavior in general. As material, we carefully selected eighteenGerman-language textbooks of psychiatry across the period 1803–2017. Previously, inGerman psychiatry, disordered eating behaviors were seen as symptoms of depressivedisorders, bipolar disorder or schizophrenia, or as manifestations of historical diagnosesno longer used by the majority of psychiatrists such as neurasthenia, hypochondria andhysteria. Interestingly, 19th and early 20th century psychiatrists like Kraepelin, Bumke,Hoff, Bleuler, and Jaspers reported symptom clusters such as food refusal and vomitingunder these outdated diagnostic categories, whereas nowadays they are listed as corecriteria for specific eating disorder subtypes. A wide range of medical conditions such asendocrinopathies, intestinal or brain lesions were also cited as causes of abnormal foodintake and body weight. An additional consideration in the delayed adoption of eatingdisorder diagnoses in German psychiatry is that people with EDs are commonly treatedin the specialty discipline of psychosomatic medicine, introduced in Germany after WorldWar II, rather than in psychiatry. Viewed from today’s perspective, the classification ofdisorders associated with disordered eating is continuously evolving. Major depressivedisorder, schizophrenia and physical diseases have been enduringly associated withabnormal eating behavior and are listed as important differential diagnoses of EDsin DSM-5. Moreover, there are overlaps regarding the neurobiological basis andpsychological and psychopharmacological therapies applied to all of these disorders

    An ALMA Survey of H₂CO in Protoplanetary Disks

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    H₂CO is one of the most abundant organic molecules in protoplanetary disks and can serve as a precursor to more complex organic chemistry. We present an Atacama Large Millimeter/submillimeter Array survey of H₂CO toward 15 disks covering a range of stellar spectral types, stellar ages, and dust continuum morphologies. H₂CO is detected toward 13 disks and tentatively detected toward a fourteenth. We find both centrally peaked and centrally depressed emission morphologies, and half of the disks show ring-like structures at or beyond expected CO snowline locations. Together these morphologies suggest that H₂CO in disks is commonly produced through both gas-phase and CO-ice-regulated grain-surface chemistry. We extract disk-averaged and azimuthally-averaged H₂CO excitation temperatures and column densities for four disks with multiple H₂CO line detections. The temperatures are between 20–50 K, with the exception of colder temperatures in the DM Tau disk. These temperatures suggest that H₂CO emission in disks generally emerges from the warm molecular layer, with some contributions from the colder midplane. Applying the same H₂CO excitation temperatures to all disks in the survey, we find that H₂CO column densities span almost three orders of magnitude (~5 × 10¹¹–5 × 10¹⁴ cm⁻²). The column densities appear uncorrelated with disk size and stellar age, but Herbig Ae disks may have less H₂CO compared to T Tauri disks, possibly because of less CO freeze-out. More H₂CO observations toward Herbig Ae disks are needed to confirm this tentative trend, and to better constrain under which disk conditions H₂CO and other oxygen-bearing organics efficiently form during planet formation
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