584 research outputs found

    He I λ10830 as a Probe of Winds in Accreting Young Stars

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    He I 10830 profiles acquired with Keck\u27s NIRSPEC for six young low-mass stars with high disk accretion rates (AS 353A, DG Tau, DL Tau, DR Tau, HL Tau, and SVS 13) provide new insight into accretion-driven winds. In four of the stars, the profiles have the signature of resonance scattering, and they possess a deep and broad blueshifted absorption that penetrates more than 50% into the 1 m continuum over a continuous range of velocities from near the stellar rest velocity to the terminal velocity of the wind, unlike inner wind signatures seen in other spectral features. This deep and broad absorption provides the first observational tracer of the acceleration region of the inner wind and suggests that this acceleration region is situated such that it occults a significant portion of the stellar disk. The remaining two stars also have blue absorption extending below the continuum, although here the profiles are dominated by emission, requiring an additional source of helium excitation beyond resonant scattering. This is likely the same process that produces the emission profiles seen at He I 5876 Å

    The Grizzly, February 12, 1988

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    Harassment Runs Rampant • Security Tips for Safe Driving • Tapping the Task Force • Schroeder for Press • Sex Still Religiously Private • Letter: Commencing the Issue • Restructuring the Ursinus Tradition: Task Force Transcends Past Goals • Speech Exam Announced • Participants Model the U.N. • Winner-Take-All in Ursinus-Moravian Showdown • Hoopsters Vastly Improved • Reckless Wrestlers Rustlin\u27 Victory • The Bigger Doesn\u27t Mean the Better • Beam Breakin\u27 Benner • \u27Mers Keep Victory Abreast • Conwell Cuts the Cake • Reflect: Success Promising • Dole Doles out Compromise • Can\u27t a Person Change His Mind? • Race for the White House: The Candidateshttps://digitalcommons.ursinus.edu/grizzlynews/1204/thumbnail.jp

    A strong-coupling analysis of two-dimensional O(N) sigma models with N3N\geq 3 on square, triangular and honeycomb lattices

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    Recently-generated long strong-coupling series for the two-point Green's functions of asymptotically free O(N){\rm O}(N) lattice σ\sigma models are analyzed, focusing on the evaluation of dimensionless renormalization-group invariant ratios of physical quantities and applying resummation techniques to series in the inverse temperature β\beta and in the energy EE. Square, triangular, and honeycomb lattices are considered, as a test of universality and in order to estimate systematic errors. Large-NN solutions are carefully studied in order to establish benchmarks for series coefficients and resummations. Scaling and universality are verified. All invariant ratios related to the large-distance properties of the two-point functions vary monotonically with NN, departing from their large-NN values only by a few per mille even down to N=3N=3.Comment: 53 pages (incl. 5 figures), tar/gzip/uuencode, REVTEX + psfi

    Spin-Glass Theory for Pedestrians

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    In these notes the main theoretical concepts and techniques in the field of mean-field spin-glasses are reviewed in a compact and pedagogical way, for the benefit of the graduate and undergraduate student. One particular spin-glass model is analyzed (the p-spin spherical model) by using three different approaches. Thermodynamics, covering pure states, overlaps, overlap distribution, replica symmetry breaking, and the static transition. Dynamics, covering the generating functional method, generalized Langevin equation, equations for the correlation and the response, the Mode Coupling approximation, and the dynamical transition. And finally complexity, covering the mean-field (TAP) free energy, metastable states, entropy crisis, threshold energy, and saddles. Particular attention has been paid on the mutual consistency of the results obtained from the different methods.Comment: Lecture notes of the school: "Unifying Concepts in Glassy Physics III", Bangalore, June 200

    Maternal corticotropin-releasing hormone is associated with LEP DNA methylation at birth and in childhood: an epigenome-wide study in Project Viva

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    BackgroundCorticotropin-releasing hormone (CRH) plays a central role in regulating the secretion of cortisol which controls a wide range of biological processes. Fetuses overexposed to cortisol have increased risks of disease in later life. DNA methylation may be the underlying association between prenatal cortisol exposure and health effects. We investigated associations between maternal CRH levels and epigenome-wide DNA methylation of cord blood in offsprings and evaluated whether these associations persisted into mid-childhood.MethodsWe investigated mother-child pairs enrolled in the prospective Project Viva pre-birth cohort. We measured DNA methylation in 257 umbilical cord blood samples using the HumanMethylation450 Bead Chip. We tested associations of maternal CRH concentration with cord blood cells DNA methylation, adjusting the model for maternal age at enrollment, education, maternal race/ethnicity, maternal smoking status, pre-pregnancy body mass index, parity, gestational age at delivery, child sex, and cell-type composition in cord blood. We further examined the persistence of associations between maternal CRH levels and DNA methylation in children's blood cells collected at mid-childhood (n = 239, age: 6.7-10.3 years) additionally adjusting for the children's age at blood drawn.ResultsMaternal CRH levels are associated with DNA methylation variability in cord blood cells at 96 individual CpG sites (False Discovery Rate <0.05). Among the 96 CpG sites, we identified 3 CpGs located near the LEP gene. Regional analyses confirmed the association between maternal CRH and DNA methylation near LEP. Moreover, higher maternal CRH levels were associated with higher blood-cell DNA methylation of the promoter region of LEP in mid-childhood (P < 0.05, β = 0.64, SE = 0.30).ConclusionIn our cohort, maternal CRH was associated with DNA methylation levels in newborns at multiple loci, notably in the LEP gene promoter. The association between maternal CRH and LEP DNA methylation levels persisted into mid-childhood

    International Veterinary Epilepsy Task Force Consensus Proposal: Diagnostic approach to epilepsy in dogs

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    This article outlines the consensus proposal on diagnosis of epilepsy in dogs by the International Veterinary Epilepsy Task Force. The aim of this consensus proposal is to improve consistency in the diagnosis of epilepsy in the clinical and research settings. The diagnostic approach to the patient presenting with a history of suspected epileptic seizures incorporates two fundamental steps: to establish if the events the animal is demonstrating truly represent epileptic seizures and if so, to identify their underlying cause. Differentiation of epileptic seizures from other non-epileptic episodic paroxysmal events can be challenging. Criteria that can be used to make this differentiation are presented in detail and discussed. Criteria for the diagnosis of idiopathic epilepsy (IE) are described in a three-tier system. Tier I confidence level for the diagnosis of IE is based on a history of two or more unprovoked epileptic seizures occurring at least 24 h apart, age at epileptic seizure onset of between six months and six years, unremarkable inter-ictal physical and neurological examination, and no significant abnormalities on minimum data base blood tests and urinalysis. Tier II confidence level for the diagnosis of IE is based on the factors listed in tier I and unremarkable fasting and post-prandial bile acids, magnetic resonance imaging (MRI) of the brain (based on an epilepsy-specific brain MRI protocol) and cerebrospinal fluid (CSF) analysis. Tier III confidence level for the diagnosis of IE is based on the factors listed in tier I and II and identification of electroencephalographic abnormalities characteristic for seizure disorders. The authors recommend performing MRI of the brain and routine CSF analysis, after exclusion of reactive seizures, in dogs with age at epileptic seizure onset 6 years, inter-ictal neurological abnormalities consistent with intracranial neurolocalisation, status epilepticus or cluster seizure at epileptic seizure onset, or a previous presumptive diagnosis of IE and drug-resistance with a single antiepileptic drug titrated to the highest tolerable dose

    The Deconfinement Phase Transition in One-Flavour QCD

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    We present a study of the deconfinement phase transition of one-flavour QCD, using the multiboson algorithm. The mass of the Wilson fermions relevant for this study is moderately large and the non-hermitian multiboson method is a superior simulation algorithm. Finite size scaling is studied on lattices of size 83×48^3\times 4, 123×412^3\times 4 and 163×416^3\times 4. The behaviours of the peak of the Polyakov loop susceptibility, the deconfinement ratio and the distribution of the norm of the Polyakov loop are all characteristic of a first-order phase transition for heavy quarks. As the quark mass decreases, the first-order transition gets weaker and turns into a crossover. To investigate finite size scaling on larger spatial lattices we use an effective action in the same universality class as QCD. This effective action is constructed by replacing the fermionic determinant with the Polyakov loop identified as the most relevant Z(3) symmetry breaking term. Higher-order effects are incorporated in an effective Z(3)-breaking field, hh, which couples to the Polyakov loop. Finite size scaling determines the value of hh where the first order transition ends. Our analysis at the end - point, heph_{ep}, indicates that the effective model and thus QCD is consistent with the universality class of the three dimensional Ising model. Matching the field strength at the end point, heph_{ep}, to the κ\kappa values used in the dynamical quark simulations we estimate the end point, κep\kappa_{ep}, of the first-order phase transition. We find κep0.08\kappa_{ep}\sim 0.08 which corresponds to a quark mass of about 1.4 GeV .Comment: LaTex, 25 pages, 18 figure
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