447 research outputs found

    Eisenstein Series of Weight One, q-Averages of the 0-Logarithm and Periods of Elliptic Curves

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    For any elliptic curve E over k ⊂ R with E(C) = C^×/q^Z, q = e^(2πiz),Im(z) >, we study the q-average D_(0,q), defined on E(C), of the function D_0(z) = Im(z/(1−z)). Let Ω+(E) denote the real period of E. We show that there is a rational function R ∈ Q(X_1(N)) such that for any non-cuspidal real point s ∈ X_1(N) (which defines an elliptic curve E(s) over R together with a point P(s) of order N), πD_(0,q)(P(s)) equals Ω+(E(s))R(s). In particular, if s is Q-rational point of X_1(N), a rare occurrence according to Mazur, R(s) is a rational number

    A Small Conductance Calcium-Activated K<sup>+</sup> Channel in C. elegans, KCNL-2, Plays a Role in the Regulation of the Rate of Egg-Laying

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    In the nervous system of mice, small conductance calcium-activated potassium (SK) channels function to regulate neuronal excitability through the generation of a component of the medium afterhyperpolarization that follows action potentials. In humans, irregular action potential firing frequency underlies diseases such as ataxia, epilepsy, schizophrenia and Parkinson's disease. Due to the complexity of studying protein function in the mammalian nervous system, we sought to characterize an SK channel homologue, KCNL-2, in C. elegans, a genetically tractable system in which the lineage of individual neurons was mapped from their early developmental stages. Sequence analysis of the KCNL-2 protein reveals that the six transmembrane domains, the potassium-selective pore and the calmodulin binding domain are highly conserved with the mammalian homologues. We used widefield and confocal fluorescent imaging to show that a fusion construct of KCNL-2 with GFP in transgenic lines is expressed in the nervous system of C. elegans. We also show that a KCNL-2 null strain, kcnl-2(tm1885), demonstrates a mild egg-laying defective phenotype, a phenotype that is rescued in a KCNL-2-dependent manner. Conversely, we show that transgenic lines that overexpress KCNL-2 demonstrate a hyperactive egg-laying phenotype. In this study, we show that the vulva of transgenic hermaphrodites is highly innervated by neuronal processes and by the VC4 and VC5 neurons that express GFP-tagged KCNL-2. We propose that KCNL-2 functions in the nervous system of C. elegans to regulate the rate of egg-laying. © 2013 Chotoo et al

    When Will Adolescents Tell Someone About Dating Violence Victimization?

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    This study examined factors that influence help-seeking among a diverse sample of adolescents who experienced dating violence. A sample of 57 high school students in an urban community reported on the prevalence and characteristics of dating violence in their relationships. Someone observing a dating violence incident and a survivor’s attaching an emotional meaning to the event significantly influenced adolescents to talk to someone. When dating violence occurred in isolation, survivors were more likely to receive no support from others in the aftermath of the incident. Differences between boys’ and girls’ help-seeking and implications for dating violence intervention and prevention programming are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90887/1/Black-Tolman-Callahan-Saunders- Weisz- 2008-When will adolescents tell someone about dating violence VAW.pd

    The Lick AGN Monitoring Project 2011: Dynamical Modeling of the Broad Line Region in Mrk 50

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    We present dynamical modeling of the broad line region (BLR) in the Seyfert 1 galaxy Mrk 50 using reverberation mapping data taken as part of the Lick AGN Monitoring Project (LAMP) 2011. We model the reverberation mapping data directly, constraining the geometry and kinematics of the BLR, as well as deriving a black hole mass estimate that does not depend on a normalizing factor or virial coefficient. We find that the geometry of the BLR in Mrk 50 is a nearly face-on thick disk, with a mean radius of 9.6(+1.2,-0.9) light days, a width of the BLR of 6.9(+1.2,-1.1) light days, and a disk opening angle of 25\pm10 degrees above the plane. We also constrain the inclination angle to be 9(+7,-5) degrees, close to face-on. Finally, the black hole mass of Mrk 50 is inferred to be log10(M(BH)/Msun) = 7.57(+0.44,-0.27). By comparison to the virial black hole mass estimate from traditional reverberation mapping analysis, we find the normalizing constant (virial coefficient) to be log10(f) = 0.78(+0.44,-0.27), consistent with the commonly adopted mean value of 0.74 based on aligning the M(BH)-{\sigma}* relation for AGN and quiescent galaxies. While our dynamical model includes the possibility of a net inflow or outflow in the BLR, we cannot distinguish between these two scenarios.Comment: Accepted for publication in ApJ. 8 pages, 6 figure

    Berkeley Supernova Ia Program I: Observations, Data Reduction, and Spectroscopic Sample of 582 Low-Redshift Type Ia Supernovae

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    In this first paper in a series we present 1298 low-redshift (z\leq0.2) optical spectra of 582 Type Ia supernovae (SNe Ia) observed from 1989 through 2008 as part of the Berkeley SN Ia Program (BSNIP). 584 spectra of 199 SNe Ia have well-calibrated light curves with measured distance moduli, and many of the spectra have been corrected for host-galaxy contamination. Most of the data were obtained using the Kast double spectrograph mounted on the Shane 3 m telescope at Lick Observatory and have a typical wavelength range of 3300-10,400 Ang., roughly twice as wide as spectra from most previously published datasets. We present our observing and reduction procedures, and we describe the resulting SN Database (SNDB), which will be an online, public, searchable database containing all of our fully reduced spectra and companion photometry. In addition, we discuss our spectral classification scheme (using the SuperNova IDentification code, SNID; Blondin & Tonry 2007), utilising our newly constructed set of SNID spectral templates. These templates allow us to accurately classify our entire dataset, and by doing so we are able to reclassify a handful of objects as bona fide SNe Ia and a few other objects as members of some of the peculiar SN Ia subtypes. In fact, our dataset includes spectra of nearly 90 spectroscopically peculiar SNe Ia. We also present spectroscopic host-galaxy redshifts of some SNe Ia where these values were previously unknown. [Abridged]Comment: 34 pages, 11 figures, 11 tables, revised version, re-submitted to MNRAS. Spectra will be released in January 2013. The SN Database homepage (http://hercules.berkeley.edu/database/index_public.html) contains the full tables, plots of all spectra, and our new SNID template

    Variable Sodium Absorption in a Low-Extinction Type Ia Supernova

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    Recent observations have revealed that some Type Ia supernovae exhibit narrow, time-variable Na I D absorption features. The origin of the absorbing material is controversial, but it may suggest the presence of circumstellar gas in the progenitor system prior to the explosion, with significant implications for the nature of the supernova progenitors. We present the third detection of such variable absorption, based on six epochs of high-resolution spectroscopy of the Type Ia supernova SN 2007le from Keck and the HET. The data span ~3 months, from 5 days before maximum light to 90 days after maximum. We find that one component of the Na D absorption lines strengthened significantly with time, indicating a total column density increase of ~2.5 x 10^12 cm^-2. The changes are most prominent after maximum light rather than at earlier times when the UV flux from the SN peaks. As with SN 2006X, we detect no change in the Ca II H&K lines over the same time period, rendering line-of-sight effects improbable and suggesting a circumstellar origin for the absorbing material. Unlike the previous two SNe exhibiting variable absorption, SN 2007le is not highly reddened (E_B-V = 0.27 mag), also pointing toward circumstellar rather than interstellar absorption. Photoionization models show that the data are consistent with a dense (10^7 cm^-3) cloud or clouds of gas located ~0.1 pc from the explosion. These results broadly support the single-degenerate scenario previously proposed to explain the variable absorption, with mass loss from a nondegenerate companion star responsible for providing the circumstellar gas. We also present tentative evidence for narrow Halpha emission associated with the SN, which will require followup observations at late times to confirm. [abridged]Comment: 16 pages, 10 figures (8 in color), 5 tables. Accepted for publication in Ap

    The Lick AGN Monitoring Project: Broad-Line Region Radii and Black Hole Masses from Reverberation Mapping of Hbeta

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    We have recently completed a 64-night spectroscopic monitoring campaign at the Lick Observatory 3-m Shane telescope with the aim of measuring the masses of the black holes in 12 nearby (z < 0.05) Seyfert 1 galaxies with expected masses in the range ~10^6-10^7 M_sun and also the well-studied nearby active galactic nucleus (AGN) NGC 5548. Nine of the objects in the sample (including NGC 5548) showed optical variability of sufficient strength during the monitoring campaign to allow for a time lag to be measured between the continuum fluctuations and the response to these fluctuations in the broad Hbeta emission. We present here the light curves for the objects in this sample and the subsequent Hbeta time lags for the nine objects where these measurements were possible. The Hbeta lag time is directly related to the size of the broad-line region, and by combining the lag time with the measured width of the Hbeta emission line in the variable part of the spectrum, we determine the virial mass of the central supermassive black hole in these nine AGNs. The absolute calibration of the black hole masses is based on the normalization derived by Onken et al. We also examine the time lag response as a function of velocity across the Hbeta line profile for six of the AGNs. The analysis of four leads to ambiguous results with relatively flat time lags as a function of velocity. However, SBS 1116+583A exhibits a symmetric time lag response around the line center reminiscent of simple models for circularly orbiting broad-line region (BLR) clouds, and Arp 151 shows an asymmetric profile that is most easily explained by a simple gravitational infall model. Further investigation will be necessary to fully understand the constraints placed on physical models of the BLR by the velocity-resolved response in these objects.Comment: 24 pages, 16 figures and 13 tables, submitted to Ap

    F-Theory and the Mordell-Weil Group of Elliptically-Fibered Calabi-Yau Threefolds

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    The Mordell-Weil group of an elliptically fibered Calabi-Yau threefold X contains information about the abelian sector of the six-dimensional theory obtained by compactifying F-theory on X. After examining features of the abelian anomaly coefficient matrix and U(1) charge quantization conditions of general F-theory vacua, we study Calabi-Yau threefolds with Mordell-Weil rank-one as a first step towards understanding the features of the Mordell-Weil group of threefolds in more detail. In particular, we generate an interesting class of F-theory models with U(1) gauge symmetry that have matter with both charges 1 and 2. The anomaly equations --- which relate the Neron-Tate height of a section to intersection numbers between the section and fibral rational curves of the manifold --- serve as an important tool in our analysis.Comment: 29 pages + appendices, 5 figures; v2: minor correction

    Ensuring due process in the IACUC and animal welfare setting: considerations in developing noncompliance policies and procedures for institutional animal care and use committees and institutional officials

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    Every institution that is involved in research with animals is expected to have in place policies and procedures for the management of allegations of noncompliance with the Animal Welfare Act and the U.S. Public Health Service Policy on the Humane Care and Use of Laboratory Animals. We present here a model set of recommendations for institutional animal care and use committees and institutional officials to ensure appropriate consideration of allegations of noncompliance with federal Animal Welfare Act regulations that carry a significant risk or specific threat to animal welfare. This guidance has 3 overarching aims: 1) protecting the welfare of research animals; 2) according fair treatment and due process to an individual accused of noncompliance; and 3) ensuring compliance with federal regulations. Through this guidance, the present work seeks to advance the cause of scientific integrity, animal welfare, and the public trust while recognizing and supporting the critical importance of animal research for the betterment of the health of both humans and animals.Ăą Hansen, B. C., Gografe, S., Pritt, S., Jen, K.Ăą L. C., McWhirter, C. A., Barman, S. M., Comuzzie, A., Greene, M., McNulty, J. A., Michele, D. E., Moaddab, N., Nelson, R. J., Norris, K., Uray, K. D., Banks, R., Westlund, K. N., Yates, B. J., Silverman, J., Hansen, K. D., Redman, B. Ensuring due process in the IACUC and animal welfare setting: considerations in developing noncompliance policies and procedures for institutional animal care and use committees and institutional officials. FASEB J. 31, 4216Ăą 4225 (2017). www.fasebj.orgPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154293/1/fsb2fj201601250r.pd
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