Tonic dopamine induces persistent changes in the transient potassium current through translational regulation

PubMed Central

Rodgers, EW; Krenz, W-D; Baro, DJ

2012-01-01

Neuromodulatory effects can vary with their mode of transmission. Phasic release produces local and transient increases in dopamine (DA) up to micromolar concentrations. Additionally, since DA is released from open synapses and reuptake mechanisms are not nearby, tonic nanomolar DA exists in the extracellular space. Do phasic and tonic transmissions similarly regulate voltage dependent ionic conductances in a given neuron? It was previously shown that DA could immediately alter the transient potassium current (IA) of identified neurons in the stomatogastric ganglion (STG) of the spiny lobster, Panulirus interruptus. Here we show that DA can also persistently alter IA, and that DA’s immediate and persistent effects oppose one another. The lateral pyloric neuron (LP) exclusively expresses type 1 DA receptors (D1Rs). Micromolar DA produces immediate depolarizing shifts in the voltage dependence of LP IA, whereas tonic nanomolar DA produces a persistent increase in LP IA maximal conductance (Gmax) through a translation dependent mechanism involving target of rapamycin (TOR). The pyloric dilator neuron (PD) exclusively expresses type 2 DA receptors (D2Rs). Micromolar DA produces an immediate hyperpolarizing shift in PD IA voltage dependence of activation, whereas tonic DA persistently decreases PD IA Gmax through a translation dependent mechanism not involving TOR. The persistent effects on IA Gmax do not depend on LP or PD activity. These data suggest a role for tonic modulators in the regulation of voltage gated ion channel number; and furthermore, that dopaminergic systems may be organized to limit the amount of change they can impose on a circuit. PMID:21917788

Type Ia supernovae: Pulsating delayed detonation models, IR light curves, and the formation of molecules

NASA Technical Reports Server (NTRS)

Hoflich, Peter; Khokhlov, A.; Wheeler, C.

1995-01-01

We computed optical and infrared light curves of the pulsating class of delayed detonation models for Type Ia supernovae (SNe Ia). It is demonstrated that observations of the IR light curves can be used to identify subluminous SNe Ia by testing whether secondary maxima occur in the IR. Our pulsating delayed detonation models are in agreement with current observations both for subluminous and normal bright SN Ia, namely SN1991bg, SN1992bo, and SN1992bc. Observations of molecular bands provide a test to distinguish whether strongly subluminous supernovae are a consequence of the pulsating mechanism occurring in a high-mass white dwarf (WD) or, alternatively, are formed by the helium detonation in a low-mass WD as was suggested by Woosley. In the latter case, no carbon is left after the explosion of low-mass WDs whereas a log of C/O-rich material is present in pulsating delayed detonation models.

Polarisation Spectral Synthesis For Type Ia Supernova Explosion Models

NASA Astrophysics Data System (ADS)

Bulla, Mattia

2017-02-01

Despite their relevance across a broad range of astrophysical research topics, Type Ia supernova explosions are still poorly understood and answers to the questions of when, why and how these events are triggered remain unclear. In this respect, polarisation offers a unique opportunity to discriminate between the variety of possible scenarios. The observational evidence that Type Ia supernovae are associated with rather low polarisation signals (smaller than a few per cent) places strong constraints for models and calls for modest asphericities in the progenitor system and/or explosion mechanism.The goal of this thesis is to assess the validity of contemporary Type Ia supernova explosion models by testing whether their predicted polarisation signatures can account for the small signals usually observed. To this end, we have implemented and tested an innovative Monte Carlo scheme in the radiative transfer code artis. Compared to previous Monte Carlo approaches, this technique produces synthetic observables (light curves, flux and polarisation spectra) with a substantial reduction in the Monte Carlo noise and therefore in the required computing time. This improvement is particularly crucial for our study as we aim to extract very weak polarisation signals, comparable to those detected in Type Ia supernovae. We have also demonstrated the applicability of this method to other classes of supernovae via a preliminary study of the first spectropolarimetry observations of superluminous supernovae.Using this scheme, we have calculated synthetic spectropolarimetry for three multi-dimensional explosion models recently proposed as promising candidates to explain Type Ia supernovae. Our findings highlight the power of spectropolarimetry in testing and discriminating between different scenarios. While all the three models predict light curves and flux spectra that are similar to each others and reproduce those observed in Type Ia supernovae comparably well, polarisation does provide a clear distinction. In particular, we find that one model is too strongly asymmetric and produces polarisation levels that are too high and clearly inconsistent with those detected for the bulk of Type Ia supernovae. Polarisation signals - and their time evolution - extracted for the remaining two models are instead in good agreement with the currently available spectropolarimetry data. Providing a powerful way to connect hydrodynamic explosion models to observed data, the study presented in this thesis is an important step towards a better understanding of Type Ia supernovae from a synthesis of theory and observations.

Electrical remodelling maintains firing properties in cortical pyramidal neurons lacking KCND2-encoded A-type K+ currents.

PubMed

Nerbonne, Jeanne M; Gerber, Benjamin R; Norris, Aaron; Burkhalter, Andreas

2008-03-15

Considerable experimental evidence has accumulated demonstrating a role for voltage-gated K(+) (Kv) channel pore-forming (alpha) subunits of the Kv4 subfamily in the generation of fast transient outward K(+), I(A), channels. Immunohistochemical data suggest that I(A) channels in hippocampal and cortical pyramidal neurons reflect the expression of homomeric Kv4.2 channels. The experiments here were designed to define directly the role of Kv4.2 in the generation of I(A) in cortical pyramidal neurons and to determine the functional consequences of the targeted deletion of Kv4.2 on the resting and active membrane properties of these cells. Whole-cell voltage-clamp recordings, obtained from visual cortical pyramidal neurons isolated from mice in which the KCND2 (Kv4.2) locus was disrupted (Kv4.2-/- mice), revealed that I(A) is indeed eliminated. In addition, the densities of other Kv current components, specifically I(K) and I(ss), are increased significantly (P < 0.001) in most ( approximately 80%) Kv4.2-/- cells. The deletion of KCND2 (Kv4.2) and the elimination of I(A) is also accompanied by the loss of the Kv4 channel accessory protein KChIP3, suggesting that in the absence of Kv4.2, the KChIP3 protein is targeted for degradation. The expression levels of several Kv alpha subunits (Kv4.3, Kv1.4, Kv2.1, Kv2.2), however, are not measurably altered in Kv4.2-/- cortices. Although I(A) is eliminated in Kv4.2-/- pyramidal neurons, the mean +/- s.e.m. current threshold for action potential generation and the waveforms of action potentials are indistinguishable from those recorded from wild-type cells. Repetitive firing is also maintained in Kv4.2-/- cortical pyramidal neurons, suggesting that the increased densities of I(K) and I(ss) compensate for the in vivo loss of I(A).

The progenitors of supernovae Type Ia

NASA Astrophysics Data System (ADS)

Toonen, Silvia

2014-09-01

Despite the significance of Type Ia supernovae (SNeIa) in many fields in astrophysics, SNeIa lack a theoretical explanation. SNeIa are generally thought to be thermonuclear explosions of carbon/oxygen (CO) white dwarfs (WDs). The canonical scenarios involve white dwarfs reaching the Chandrasekhar mass, either by accretion from a non-degenerate companion (single-degenerate channel, SD) or by a merger of two CO WDs (double-degenerate channel, DD). The study of SNeIa progenitors is a very active field of research for binary population synthesis (BPS) studies. The strength of the BPS approach is to study the effect of uncertainties in binary evolution on the macroscopic properties of a binary population, in order to constrain binary evolutionary processes. I will discuss the expected SNeIa rate from the BPS approach and the uncertainties in their progenitor evolution, and compare with current observations. I will also discuss the results of the POPCORN project in which four BPS codes were compared to better understand the differences in the predicted SNeIa rate of the SD channel. The goal of this project is to investigate whether differences in the simulated populations are due to numerical effects or whether they can be explained by differences in the input physics. I will show which assumptions in BPS codes affect the results most and hence should be studied in more detail.

The selective A-type K+ current blocker Tx3-1 isolated from the Phoneutria nigriventer venom enhances memory of naïve and Aβ(25-35)-treated mice.

PubMed

Gomes, Guilherme M; Dalmolin, Gerusa D; Cordeiro, Marta do Nascimento; Gomez, Marcus V; Ferreira, Juliano; Rubin, Maribel A

2013-12-15

Potassium channels regulate many neuronal functions, including neuronal excitability and synaptic plasticity, contributing, by these means, to mnemonic processes. In particular, A-type K(+) currents (IA) play a key role in hippocampal synaptic plasticity. Therefore, we evaluated the effect of the peptidic toxin Tx3-1, a selective blocker of IA currents, extracted from the venom of the spider Phoneutria nigriventer, on memory of mice. Administration of Tx3-1 (i.c.v., 300 pmol/site) enhanced both short- and long-term memory consolidation of mice tested in the novel object recognition task. In comparison, 4-aminopyridine (4-AP; i.c.v., 30-300 pmol/site), a non-selective K(+) channel blocker did not alter long-term memory and caused toxic side effects such as circling, freezing and tonic-clonic seizures. Moreover, Tx3-1 (i.c.v., 10-100 pmol/site) restored memory of Aβ25-35-injected mice, and exhibited a higher potency to improve memory of Aβ25-35-injected mice when compared to control group. These results show the effect of the selective blocker of IA currents Tx3-1 in both short- and long-term memory retention and in memory impairment caused by Aβ25-35, reinforcing the role of IA in physiological and pathological memory processes. Copyright © 2013 Elsevier Ltd. All rights reserved.

Imprints of explosion conditions on late-time spectra of type Ia supernovae

NASA Astrophysics Data System (ADS)

Diamond, Tiara R.

Type Ia supernovae (SNe Ia) play a vital role in the discrimination of different cosmological models. These events have been shown to be standardizable based on properties of their light curves during the early-time photospheric phase. However, the distribution of types of progenitor system, the explosion trigger, and the physics of the explosion are still an active topic of discussion. The details of the progenitors and explosion may provide insight into the variation seen in Type Ia supernova light curves and spectra, and therefore, allow for additional methods of standardization among the group. Late-time near-infrared spectral observations for SNe Ia show numerous strong emission features of forbidden line transitions of cobalt and iron, tracing the central distribution of iron-group burning products. As the spectrum ages, the cobalt features fade as expected from the decay of 56Co to 56Fe. This work will show that the strong and isolated [Fe II] emission line at 1.644 mum provides a unique tool to analyze near-infrared spectra of SNe Ia. Several new methods of analysis will be demonstrated to determine some of the initial conditions of the system. The initial central density, rhoc, and the extent of mixing in the central regions of the explosion have signatures in the line profiles of late-time spectra. An embedded magnetic field, B, of the white dwarf can be determined using the evolution of the lines profiles. Currently magnetic field effects are not included in the hydrodynamics and radiation transport of simulations of SNe Ia. Normalization of spectra to the 1.644 mum line allows separation of features produced by stable versus unstable isotopes of iron group elements. Implications for potential progenitor systems, explosion mechanisms, and the origins and morphology of magnetic fields in SNe Ia, in addition to limitations of the method, are discussed. Observations of the late-time near-infrared emission spectrum at multiple epochs allow for the first ever analysis of the evolution of the 1.644 mum line profile for a SNe Ia. These late-time data are really pushing the observational limits of current ground-based telescopes in terms of a dim target and low signal-to-noise. The new analysis method presented in this work is used on observations of SN 2005df to constrain the initial conditions of those systems. Finally, the details and limitations of the method are presented for use with SN 2014J and future time-series observations, which will dramatically increase in number and signal-to-noise with the next-generation of telescopes and missions.

Tolerance of Sulfolobus SMV1 virus to the immunity of I-A and III-B CRISPR-Cas systems in Sulfolobus islandicus.

PubMed

Guo, Tong; Han, Wenyuan; She, Qunxin

2018-04-09

Sulfolobus islandicus Rey15A encodes one type I-A and two type III-B systems, all of which are active in mediating nucleic acids interference. However, the effectiveness of each CRISPR system against virus infection was not tested in this archaeon. Here we constructed S. islandicus strains that constitutively express the antiviral immunity from either I-A, or III-B, or I-A plus III-B systems against SMV1 and tested the response of each host to SMV1 infection. We found that, although both CRISPR immunities showed a strongly inhibition to viral DNA replication at an early stage of incubation, the host I-A CRISPR immunity gradually lost the control on virus proliferation, allowing accumulation of cellular viral DNA and release of a large number of viral particles. In contrast, the III-B CRISPR immunity showed a tight control on both viral DNA replication and virus particle formation. Furthermore, the SMV1 tolerance to the I-A CRISPR immunity did not result from the occurrence of escape mutations, suggesting the virus probably encodes an anti-CRISPR protein (Acr) to compromise the host I-A CRISPR immunity. Together, this suggests that the interplay between viral Acrs and CRISPR-Cas systems in thermophilic archaea could have shaped the stable virus-host relationship currently seen for many archaeal viruses.

Non-Local Thermodynamic Equilibrium Spectrum Synthesis of Type IA Supernovae

NASA Astrophysics Data System (ADS)

Nugent, Peter Edward

1997-09-01

Type Ia supernovae (SNe Ia) are valuable distance indicators for cosmology and the elements they eject are are important for nucleosynthesis. They appear to be thermonuclear disruptions of carbon-oxygen white dwarfs that accrete from companion stars until they approach the Chandrasekbar mass, and there is a suspicion that the propagation of the nuclear burning front involves a transition from a deflagration to a detonation. Detailed modeling of the atmospheres and spectra of SNe Ia is needed to advance our understanding of SNe Ia. Comparison of synthetic and observed spectra provides information on the temperature, density, velocity, and composition of the ejected matter and thus constrain hydrodynamical models. In addition, the expanding photosphere method yields distances to individual events that are independent of distances based on the decay of 56Ni in SNe Ia and of Cepheid variable stars in the parent galaxies. This thesis is broken down into 4 major sections, each highlighting a different way with which to use spectrum synthesis to analyze SNe Ia. Chapters 2 and 3 look at normal SNe Ia and their potential use as distance indicators using SEAM. Chapter 4 examines spectral correlations with luminosity in SNe Ia and provides a plausible explanation for these correlations via spectrum synthesis. In Chapter 5 the spectra of various hydrodynamical models are calculated in an effort to answer the question of which current progenitor/explosion model is the most plausible for a SN Ia. Finally, we look at the importance of NLTE calculations and line identifications in Chapter 6. Also included are two appendices which contain more technical information concerning γ-ray deposition and the thermalization parameter.

Serotonin type-1D receptor stimulation of A-type K(+) channel decreases membrane excitability through the protein kinase A- and B-Raf-dependent p38 MAPK pathways in mouse trigeminal ganglion neurons.

PubMed

Zhao, Xianyang; Zhang, Yuan; Qin, Wenjuan; Cao, Junping; Zhang, Yi; Ni, Jianqiang; Sun, Yangang; Jiang, Xinghong; Tao, Jin

2016-08-01

Although recent studies have implicated serotonin 5-HT1B/D receptors in the nociceptive sensitivity of primary afferent neurons, the underlying molecular and cellular mechanisms remain unclear. In this study, we identified a novel functional role of the 5-HT1D receptor subtype in regulating A-type potassium (K(+)) currents (IA) as well as membrane excitability in small trigeminal ganglion (TG) neurons. We found that the selective activation of 5-HT1D, rather than 5-HT1B, receptors reversibly increased IA, while the sustained delayed rectifier K(+) current was unaffected. The 5-HT1D-mediated IA increase was associated with a depolarizing shift in the voltage dependence of inactivation. Blocking G-protein signaling with pertussis toxin or by intracellular application of a selective antibody raised against Gαo or Gβ abolished the 5-HT1D effect on IA. Inhibition of protein kinase A (PKA), but not of phosphatidylinositol 3-kinase or protein kinase C, abolished the 5-HT1D-mediated IA increase. Analysis of phospho-p38 (p-p38) revealed that activation of 5-HT1D, but not 5-HT1B, receptors significantly activated p38, while p-ERK and p-JNK were unaffected. The p38 MAPK inhibitor SB203580, but not its inactive analogue SB202474, and inhibition of B-Raf blocked the 5-HT1D-mediated IA response. Functionally, we observed a significantly decreased action potential firing rate induced by the 5-HT1D receptors; pretreatment with 4-aminopyridine abolished this effect. Taken together, these results suggest that the activation of 5-HT1D receptors selectively enhanced IA via the Gβγ of the Go-protein, PKA, and the sequential B-Raf-dependent p38 MAPK signaling cascade. This 5-HT1D receptor effect may contribute to neuronal hypoexcitability in small TG neurons. Copyright © 2016 Elsevier Inc. All rights reserved.

Isoflurane depolarizes bronchopulmonary C neurons by inhibiting transient A-type and delayed rectifier potassium channels.

PubMed

Zhang, Zhenxiong; Zhuang, Jianguo; Zhang, Cancan; Xu, Fadi

2013-04-01

Inhalation of isoflurane (ISO), a widely used volatile anesthetic, can produce clinical tachypnea. In dogs, this response is reportedly mediated by bronchopulmonary C-fibers (PCFs), but the relevant mechanisms remain unclear. Activation of transient A-type potassium current (IA) channels and delayed rectifier potassium current (IK) channels hyperpolarizes neurons, and inhibition of both channels by ISO increases neural firing. Due to the presence of these channels in the cell bodies of rat PCFs, we determined whether ISO could stimulate PCFs to produce tachypnea in anesthetized rats, and, if so, whether this response resulted from ISO-induced depolarization of the pulmonary C neurons via the inhibition of IA and IK. We recorded ventilatory responses to 5% ISO exposure in anesthetized rats before and after blocking PCF conduction and the responses of pulmonary C neurons (extracellularly recorded) to ISO exposure. ISO-induced (1mM) changes in pulmonary C neuron membrane potential and IA/IK were tested using the perforated patch clamp technique. We found that: (1) ISO inhalation evoked a brief tachypnea (∼7s) and that this response disappeared after blocking PCF conduction; (2) the ISO significantly elevated (by 138%) the firing rate of most pulmonary C neurons (17 out of 21) in the nodose ganglion; and (3) ISO perfusion depolarized the pulmonary C neurons in the vitro and inhibited both IA and IK, and this evoked-depolarization was largely diminished after blocking both IA and IK. Our results suggest that ISO is able to stimulate PCFs to elicit tachypnea in rats, at least partly, via inhibiting IA and IK, thereby depolarizing the pulmonary C neurons. Copyright © 2013. Published by Elsevier B.V.

A Second Ladder: Testing for Bias in the Type Ia Distance Scale with SBF

NASA Astrophysics Data System (ADS)

Milne, Peter

2016-10-01

We propose obtaining Surface Brightness Fluctuation (SBF) distances to the hosts galaxies of 20 nearby type Ia supernovae (SNe Ia), resulting in a sample of 29 SNe Ia in 27 galaxies when combined with HST-SBF distances from the literature. This sample can then be compared with the existing 18 SN Ia distances from Cepheids. Through these comparisons, we will determine if there are any discrepancies between the SBF distance scale, which is extended into the Hubble flow using early-type galaxies, and the SNIa distance scale, for which local calibrators are scarce and host galaxy types and SN environments are heterogenous. Since recent measurements of UV-optical colors suggest that SN Ia properties do depend on galaxy type and environment, it is essential that SNe Ia in all galaxy types are included when extending SN Ia distances to the distant Hubble flow. Since the conclusion that universal expansion is accelerating was originally based on SNe Ia distances, and because recent measurements of UV-optical colors suggest that SN Ia properties do depend on galaxy type and environment, it is essential to measure the same types of SNe in the same types of galaxies. To meet this goal, we propose to measure high-precision SBF distances to all early-type galaxies that have hosted SNIa within 80 Mpc. We will therefore be able to distinguish between systematic offsets in the derived Hubble constant between galaxies and/or SNe of different types and correct for them. SBF is the only distance measurement technique with statistical uncertainties comparable to SN Ia that can be applied to the early-type of galaxies in which the majority of the high-redshift SNIa occur.

The Search for Lensed Supernovae

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2017-01-01

Type Ia supernovae that have multiple images due to gravitational lensing can provide us with a wealth of information both about the supernovae themselves and about our surrounding universe. But how can we find these rare explosions?Clues from Multiple ImagesWhen light from a distant object passes by a massive foreground galaxy, the galaxys strong gravitational pull can bend the light, distorting our view of the backgroundobject. In severe cases, this process can cause multiple images of the distant object to appear in the foreground lensing galaxy.An illustration of gravitational lensing. Light from the distant supernova is bent as it passes through a giant elliptical galaxy in the foreground, causing multiple images of the supernova to appear to be hosted by the elliptical galaxy. [Adapted from image by NASA/ESA/A. Feild (STScI)]Observations of multiply-imaged Type Ia supernovae (explosions that occur when white dwarfs in binary systems exceed their maximum allowed mass) could answer a number of astronomical questions. Because Type Ia supernovae are standard candles, distant, lensed Type Ia supernovae can be used to extend the Hubble diagram to high redshifts. Furthermore, the lensing time delays from the multiply-imaged explosion can provide high-precision constraints on cosmological parameters.The catch? So far, weve only found one multiply-imaged Type Ia supernova: iPTF16geu, discovered late last year. Were going to need a lot more of them to develop a useful sample! So how do we identify themutiply-imaged Type Ias among the many billions of fleeting events discovered in current and future surveys of transients?Searching for AnomaliesAbsolute magnitudes for Type Ia supernovae in elliptical galaxies. None are expected to be above -20 in the B band, so if we calculate a magnitude for a Type Ia supernova thats larger than this, its probably not hosted by the galaxy we think it is! [Goldstein Nugent 2017]Two scientists from University of California, Berkeley and Lawrence Berkeley National Laboratory have a plan. In a recent publication, Daniel Goldstein and Peter Nugent propose the following clever procedure to apply to data from transient surveys:From the data, select only the supernova candidates that appear to be hosted by quiescent elliptical galaxies.Use the host galaxies photometric redshifts to calculate absolute magnitudes for the supernovae in this sample.Select from this only the supernovae above the maximum absolute magnitude expected for Type Ia supernovae.Supernovae selected in this way are likely tricking us: their apparent hosts are probably not their hosts at all! Instead, the supernova is likely behind the galaxy, and the galaxy is just lensing its light. Using this strategy therefore allows us to select supernova candidates that are most likely to be distant, gravitationally lensed Type Ia supernovae.Redshift distribution of the multiply-imaged Type Ia supernovae the authors estimate will be detectable by ZTF and LSST in their respective 3- and 10-year survey durations. [Goldstein Nugent 2017]A convenient aspect of Goldstein and Nugents technique is that we dont need to be able to resolve the lensed multiple images for discovery. This is useful, because ground-based optical surveys dont have the resolution to see the separate images yet theyll still be useful for discovering multiply-imaged supernovae.Future ProspectsHow useful? Goldstein and Nugent use Monte Carlo simulations to estimate how many multiply-imaged Type Ia supernovae will be discoverable with future survey projects. They find that theZwicky Transient Facility (ZTF), which will begin operating this year, should be able to find up to 10 using this technique in a 3-year search. The Large Synoptic Survey Telescope (LSST), which should start operating in 2022, will be able to find around 500 multiply-imaged Type Ia supernovae in a 10-year survey.CitationDaniel A. Goldstein and Peter E. Nugent 2017 ApJL 834 L5. doi:10.3847/2041-8213/834/1/L5

Dynamic, nonlinear feedback regulation of slow pacemaking by A-type potassium current in ventral tegmental area neurons.

PubMed

Khaliq, Zayd M; Bean, Bruce P

2008-10-22

We analyzed ionic currents that regulate pacemaking in dopaminergic neurons of the mouse ventral tegmental area by comparing voltage trajectories during spontaneous firing with ramp-evoked currents in voltage clamp. Most recordings were made in brain slice, with key experiments repeated using acutely dissociated neurons, which gave identical results. During spontaneous firing, net ionic current flowing between spikes was calculated from the time derivative of voltage multiplied by cell capacitance, signal-averaged over many firing cycles to enhance resolution. Net inward interspike current had a distinctive nonmonotonic shape, reaching a minimum (generally <1 pA) between -60 and -55 mV. Under voltage clamp, ramps over subthreshold voltages elicited a time- and voltage-dependent outward current that peaked near -55 mV. This current was undetectable with 5 mV/s ramps and increased steeply with depolarization rate over the range (10-50 mV/s) typical of natural pacemaking. Ramp-evoked subthreshold current was resistant to alpha-dendrotoxin, paxilline, apamin, and tetraethylammonium but sensitive to 4-aminopyridine and 0.5 mM Ba2+, consistent with A-type potassium current (I(A)). Same-cell comparison of currents elicited by various ramp speeds with natural spontaneous depolarization showed how the steep dependence of I(A) on depolarization rate results in small net inward currents during pacemaking. These results reveal a mechanism in which subthreshold I(A) is near zero at steady state, but is engaged at depolarization rates >10 mV/s to act as a powerful, supralinear feedback element. This feedback mechanism explains how net ionic current can be constrained to <1-2 pA but reliably inward, thus enabling slow, regular firing.

Examination of the Effects of Arsenic on Glucose Homeostasis in Cell Culture and Animal Studies: Development of a Mouse Model for Arsenic-Induced Diabetes

PubMed Central

Paul, David S.; Hernández-Zavala, Araceli; Walton, Felecia S.; Adair, Blakely M.; dina, Jiří D; Matoušek, Tomáš; Stýblo, Miroslav

2009-01-01

Previous epidemiologic studies found increased prevalences of type 2 diabetes mellitus in populations exposed to high levels of inorganic arsenic (iAs) in drinking water. Although results of epidemiologic studies in low-exposure areas or occupational settings have been inconclusive, laboratory research has shown that exposures to iAs can produce effects that are consistent with type 2 diabetes. The current paper reviews the results of laboratory studies that examined the effects of iAs on glucose metabolism and describes new experiments in which the diabetogenic effects of iAs exposure were reproduced in a mouse model. Here, weanling male C57BL/6 mice drank deionized water with or without the addition of arsenite (25 or 50 ppm As) for 8 weeks. Intraperitoneal glucose tolerance tests revealed impaired glucose tolerance in mice exposed to 50 ppm As, but not to 25 ppm As. Exposure to 25 and 50 ppm As in drinking-water resulted in proportional increases in the concentration of iAs and its metabolites in the liver and in organs targeted by type 2 diabetes, including pancreas, skeletal muscle and adipose tissue. Dimethylarsenic was the predominant form of As in the tissues of mice in both 25 and 50 ppm groups. Notably, the average concentration of total speciated arsenic in livers from mice in the 50 ppm group was comparable to the highest concentration of total arsenic reported in the livers of Bangladeshi residents who had consumed water with an order of magnitude lower level of iAs. These data suggest that mice are less susceptible than humans to the diabetogenic effects of chronic exposure to iAs due to a more efficient clearance of iAs or its metabolites from target tissues. PMID:17336358

Mass spectrometry and immunoassay: how to measure steroid hormones today and tomorrow.

PubMed

Taylor, Angela E; Keevil, Brian; Huhtaniemi, Ilpo T

2015-08-01

The recent onslaught of mass spectrometry (MS) to measurements of steroid hormones, including demands that they should be the only acceptable method, has confused clinicians and scientists who have relied for more than 40 years on a variety of immunoassay (IA) methods in steroid hormone measurements. There is little doubt that MS methods with their superior specificity will be the future method of choice in many clinical and research applications of steroid hormone measurement. However, the majority of steroid measurements are currently, and will continue to be, carried out using various types of IAs for several reasons, including their technical ease, cost and availability of commercial reagents. Speedy replacement of all IAs with MS is an unrealistic and unnecessary goal, because the availability of MS measurements is limited by cost, need of expensive equipment, technical demands and lack of commercial applications. Furthermore, IAs have multiple well-known advantages that vindicate their continuing use. The purpose of this article is to elucidate the advantages and limitations of the MS and IA techniques from two angles, i.e. promotion of MS and defence of IA. The purpose of the text is to give the reader an unbiased view about the current state and future trends of steroid analysis and to help him/her choose the correct assay method to serve his/her diagnostic and research needs. © 2015 European Society of Endocrinology.

Genetic polymorphisms in bone morphogenetic protein receptor type IA gene predisposes individuals to ossification of the posterior longitudinal ligament of the cervical spine via the smad signaling pathway.

PubMed

Wang, Hao; Jin, Weitao; Li, Haibin

2018-02-20

The present study investigated the molecular mechanisms underlying the 4A > C and -349C > T single nucleotide polymorphisms (SNPs) in bone morphogenetic protein receptor type IA (BMPR-IA) gene, which significantly associated with the occurrence and the extent of ossification of the posterior longitudinal ligament (OPLL) in the cervical spine. The SNPs in BMPR-IA gene were genotyped, and the association with the occurrence and severity of OPLL were evaluated in 356 OPLL patients and 617 non-OPLL controls. In stably transfected mouse embryonic mesenchymal stem cells (C3H10T1/2), the expression levels of the BMPR-IA gene and Smad4 protein as well as phosphorylated Smad1/5/8 were detected by Western blotting. In addition, the alkaline phosphatase (ALP) and osteocalcin (OC) activity of osteogenesis specificity protein was assessed using the ALP quantitation and osteocalcin radioimmunoassay kit, respectively. The 4A > C and the -349C > T polymorphisms of BMPR-IA gene were significantly associated with the development of OPLL in the cervical spine. The C allele type in 4A > C polymorphism significantly increases the occurrence and the extent of OPLL. The T allele type in -349C > T polymorphism significantly increases the susceptibility to OPLL, but not the extent of OPLL. The current results further validate our previous observations. The expression levels of BMPR-IA gene were significantly increased in pcDNA3.1/BMPR-IA (mutation type, MT -349C > T; MT 4A > C; MT -349C > T and 4A > C) vector-transfected C3H10T1/2 cells compared to the wild type (WT) vector-transfected cells. The levels of phosphorylated Smad1/5/8 and ALP activity were significantly increased in pcDNA3.1/BMPR-IA (MT -349C > T) vector-transfected C3H10T1/2 cells compared to the WT vector-transfected cells. However, no significant differences were observed in the protein levels of phosphorylated Smad1/5/8 and the ALP activity between MT A/C and WT vector-transfected cells. In addition, no significant differences were observed in the Smad4 protein levels among the experimental groups, as well as in the OC activity between WT vector-transfected and MT C/T, MT A/C, MT C/T and MT A/C vector-transfected cells. Our results suggest that Smad signaling pathway may play important roles in the pathological process of OPLL induced by SNPs in BMPR-IA gene. These results will help to clarify the molecular mechanisms underlying the SNP and gene susceptibility to OPLL.

Young adult romantic couples' conflict resolution and satisfaction varies with partner's attention-deficit/hyperactivity disorder type.

PubMed

Canu, Will H; Tabor, Lindsey S; Michael, Kurt D; Bazzini, Doris G; Elmore, Alexis L

2014-10-01

Attention-deficit/hyperactivity disorder (ADHD) has previously been associated with less satisfaction and success in romantic relationships. This study compares conflict resolution and problem-solving behaviors in young adult romantic couples either having one partner with ADHD combined type (C-couples), having one partner identified with ADHD inattentive type (IA-couples), or in which neither partner has an ADHD diagnosis (nondiagnosed [ND] couples). Self-reports of current and childhood ADHD symptoms corroborated diagnostic status and speaker and listener behaviors, coded via the Rapid Couples Interaction Scoring System (Gottman, 1996), were the primary dependent variables. Analyses revealed greater negativity and less positivity in C-couples' behavior during a conflict resolution task, relative to IA and ND couples, and this corresponded with couples' relational satisfaction. IA-couples emitted relational behavior that was largely similar to ND couples. Findings support that relational impairment exists in C-couples, and to some degree, contrast with previous research suggesting that individuals with predominant inattention experience greater social impairment in adulthood than those with other types of ADHD. © 2013 American Association for Marriage and Family Therapy.

Identification of Unique Antigenic Determinants in the Amino Terminus of IA-2 (ICA512) in Childhood and Adult Autoimmune Diabetes: New Biomarker Development.

PubMed

Acevedo-Calado, Maria; James, Eddie A; Morran, Michael P; Pietropaolo, Susan L; Ouyang, Qin; Arribas-Layton, David; Songini, Marco; Liguori, Marco; Casu, Anna; Auchus, Richard J; Huang, Shuai; Yu, Liping; Michels, Aaron; Gianani, Roberto; Pietropaolo, Massimo

2017-04-01

The characterization of diverse subtypes of diabetes is a dynamic field of clinical research and an active area of discussion. The objective of this study was to identify new antigenic determinants in the neuroendocrine autoantigen IA-2 (ICA512) and assess whether circulating autoantibodies directed to new IA-2 epitopes identify autoimmune diabetes in young and adult populations with diabetes. Clinically diagnosed patients with type 2 diabetes ( n = 258; diabetes duration: 0.01-31 years) were evaluated using a new biomarker detecting autoantibodies directed to the extracellular domain of the neuroendocrine autoantigen IA-2 (IA-2ec). The proportion of IA-2ec autoantibodies was also evaluated in newly diagnosed patients with type 1 diabetes ( n = 150; diabetes duration: 0.04-0.49 years). In addition, IA-2 (intracellular domain), GAD65, and zinc transporter 8 autoantibodies were assayed. IA-2ec autoantibodies were detected in patients with type 1 diabetes and, surprisingly, in 5% of patients with type 2 diabetes without serologic responses to other IA-2 antigenic epitopes or other islet autoantigens. We also assessed the ability of IA-2ec-derived peptides to elicit CD4 + T-cell responses by stimulating peripheral blood mononuclear cells from patients with type 1 diabetes ( n = 18) and HLA-matched healthy subjects ( n = 13) with peptides and staining with the peptide/DQ8-specific tetramers, observing disease-associated responses to previously unreported epitopes within IA-2ec. We developed a new antibody biomarker identifying novel antigenic determinants within the N terminus of IA-2. IA-2ec autoantibodies can be detected in patients with type 1 diabetes and in a subgroup of adult autoimmune patients with type 2 diabetes phenotype negative for conventional islet autoantibody testing. These observations suggest that islet autoimmunity may be more common in clinically diagnosed type 2 diabetes than previously observed. © 2017 by the American Diabetes Association.

The Foundation Supernova Survey: motivation, design, implementation, and first data release

NASA Astrophysics Data System (ADS)

Foley, Ryan J.; Scolnic, Daniel; Rest, Armin; Jha, S. W.; Pan, Y.-C.; Riess, A. G.; Challis, P.; Chambers, K. C.; Coulter, D. A.; Dettman, K. G.; Foley, M. M.; Fox, O. D.; Huber, M. E.; Jones, D. O.; Kilpatrick, C. D.; Kirshner, R. P.; Schultz, A. S. B.; Siebert, M. R.; Flewelling, H. A.; Gibson, B.; Magnier, E. A.; Miller, J. A.; Primak, N.; Smartt, S. J.; Smith, K. W.; Wainscoat, R. J.; Waters, C.; Willman, M.

2018-03-01

The Foundation Supernova Survey aims to provide a large, high-fidelity, homogeneous, and precisely calibrated low-redshift Type Ia supernova (SN Ia) sample for cosmology. The calibration of the current low-redshift SN sample is the largest component of systematic uncertainties for SN cosmology, and new data are necessary to make progress. We present the motivation, survey design, observation strategy, implementation, and first results for the Foundation Supernova Survey. We are using the Pan-STARRS telescope to obtain photometry for up to 800 SNe Ia at z ≲ 0.1. This strategy has several unique advantages: (1) the Pan-STARRS system is a superbly calibrated telescopic system, (2) Pan-STARRS has observed 3/4 of the sky in grizyP1 making future template observations unnecessary, (3) we have a well-tested data-reduction pipeline, and (4) we have observed ˜3000 high-redshift SNe Ia on this system. Here, we present our initial sample of 225 SN Ia grizP1 light curves, of which 180 pass all criteria for inclusion in a cosmological sample. The Foundation Supernova Survey already contains more cosmologically useful SNe Ia than all other published low-redshift SN Ia samples combined. We expect that the systematic uncertainties for the Foundation Supernova Sample will be two to three times smaller than other low-redshift samples. We find that our cosmologically useful sample has an intrinsic scatter of 0.111 mag, smaller than other low-redshift samples. We perform detailed simulations showing that simply replacing the current low-redshift SN Ia sample with an equally sized Foundation sample will improve the precision on the dark energy equation-of-state parameter by 35 per cent, and the dark energy figure of merit by 72 per cent.

A single-degenerate channel for the progenitors of Type Ia supernovae with different metallicities

NASA Astrophysics Data System (ADS)

Meng, X.; Chen, X.; Han, Z.

2009-06-01

A single-degenerate channel for the progenitors of Type Ia supernovae (SNe Ia) is currently accepted, in which a carbon-oxygen white dwarf (CO WD) accretes hydrogen-rich material from its companion, increases its mass to the Chandrasekhar mass limit and then explodes as a SN Ia. Incorporating the prescription of Hachisu et al. for the accretion efficiency into Eggleton's stellar evolution code, and assuming that the prescription is valid for all metallicities, we performed binary stellar evolution calculations for more than 25000 close WD binaries with metallicities Z = 0.06, 0.05, 0.04, 0.03, 0.02, 0.01, 0.004, 0.001, 0.0003 and 0.0001. For our calculations, the companions are assumed to be unevolved or slightly evolved stars (WD + MS). As a result, the initial parameter spaces for SNe Ia at various Z are presented in the orbital period-secondary mass (logPi, Mi2) plane. Our study shows that both the initial mass of the secondary and the initial orbital period increase with metallicity. Thus, the minimum mass of the CO WD for SNe Ia decreases with metallicity Z. The difference in the minimum mass may be as large as 0.24Msolar for different Z. Adopting the results above, we studied the birth rate of SNe Ia for various Z via a binary population synthesis approach. If a single starburst is assumed, SNe Ia occur systemically earlier and the peak value of the birth rate is larger for a high Z. The Galactic birth rate from the WD + MS channel is lower than (but comparable to) that inferred from observations. Our study indicates that supernovae like SN2002ic will not occur in extremely low-metallicity environments, if the delayed dynamical-instability model is appropriate.

The Type Ia Supernova Color-Magnitude Relation and Host Galaxy Dust: A Simple Hierarchical Bayesian Model

NASA Astrophysics Data System (ADS)

Mandel, Kaisey S.; Scolnic, Daniel M.; Shariff, Hikmatali; Foley, Ryan J.; Kirshner, Robert P.

2017-06-01

Conventional Type Ia supernova (SN Ia) cosmology analyses currently use a simplistic linear regression of magnitude versus color and light curve shape, which does not model intrinsic SN Ia variations and host galaxy dust as physically distinct effects, resulting in low color-magnitude slopes. We construct a probabilistic generative model for the dusty distribution of extinguished absolute magnitudes and apparent colors as the convolution of an intrinsic SN Ia color-magnitude distribution and a host galaxy dust reddening-extinction distribution. If the intrinsic color-magnitude (M B versus B - V) slope {β }{int} differs from the host galaxy dust law R B , this convolution results in a specific curve of mean extinguished absolute magnitude versus apparent color. The derivative of this curve smoothly transitions from {β }{int} in the blue tail to R B in the red tail of the apparent color distribution. The conventional linear fit approximates this effective curve near the average apparent color, resulting in an apparent slope {β }{app} between {β }{int} and R B . We incorporate these effects into a hierarchical Bayesian statistical model for SN Ia light curve measurements, and analyze a data set of SALT2 optical light curve fits of 248 nearby SNe Ia at z< 0.10. The conventional linear fit gives {β }{app}≈ 3. Our model finds {β }{int}=2.3+/- 0.3 and a distinct dust law of {R}B=3.8+/- 0.3, consistent with the average for Milky Way dust, while correcting a systematic distance bias of ˜0.10 mag in the tails of the apparent color distribution. Finally, we extend our model to examine the SN Ia luminosity-host mass dependence in terms of intrinsic and dust components.

Diminished A-type potassium current and altered firing properties in presympathetic PVN neurones in renovascular hypertensive rats

PubMed Central

Sonner, Patrick M; Filosa, Jessica A; Stern, Javier E

2008-01-01

Accumulating evidence supports a contribution of the hypothalamic paraventricular nucleus (PVN) to sympathoexcitation and elevated blood pressure in renovascular hypertension. However, the underlying mechanisms resulting in altered neuronal function in hypertensive rats remain largely unknown. Here, we aimed to address whether the transient outward potassium current (IA) in identified rostral ventrolateral medulla (RVLM)-projecting PVN neurones is altered in hypertensive rats, and whether such changes affected single and repetitive action potential properties and associated changes in intracellular Ca2+ levels. Patch-clamp recordings obtained from PVN-RVLM neurons showed a reduction in IA current magnitude and single channel conductance, and an enhanced steady-state current inactivation in hypertensive rats. Morphometric reconstructions of intracellularly labelled PVN-RVLM neurons showed a diminished dendritic surface area in hypertensive rats. Consistent with a diminished IA availability, action potentials in PVN-RVLM neurons in hypertensive rats were broader, decayed more slowly, and were less sensitive to the K+ channel blocker 4-aminopyridine. Simultaneous patch clamp recordings and confocal Ca2+ imaging demonstrated enhanced action potential-evoked intracellular Ca2+ transients in hypertensive rats. Finally, spike broadening during repetitive firing discharge was enhanced in PVN-RVLM neurons from hypertensive rats. Altogether, our results indicate that diminished IA availability constitutes a contributing mechanism underlying aberrant central neuronal function in renovascular hypertension. PMID:18238809

[Regulation of pyloric rhythm by I(A) and I(h) in crayfish stomatogastric ganglion].

PubMed

Kuang, Guo-Hui; Liu, Yi-Hui; Ren, Wei

2012-06-25

The stomatogastric ganglion (STG) of shellfish includes 30 neurons and produces pyloric rhythms. It is the common model to study central pattern generator (CPG). Regulation of pyloric rhythms not only is related to the property of single neurons in STG but also depends on the connections and property of the whole neuronal network. It has been found that transient potassium current (I(A)) and hyperpolarization-activated cation current (I(h)) exist in certain types of neurons of STG. However, roles played by these two currents in maintaining and regulating the pyloric rhythms are unknown. In the present study, in vitro electrophysiological recordings were performed on crayfish STG to examine the role played by I(A) and I(h) in regulation of pyloric rhythm. 4AP (2 mmol/L), a specific inhibitor of I(A), caused a decrease in pyloric cycle (P < 0.01), an increase in PD (pyloric dilator) ratio, a decrease in PY (pyloric) ratio (P < 0.01) and delay of phases of LP and PY firing. ZD7288 (100 μmol/L), a specific inhibitor of I(h), caused a decrease in pyloric cycle (P < 0.01), an increase in PD ratio (P < 0.01), an increase in LP (lateral pyloric) ratio (P < 0.01), a decrease in PY ratio (P < 0.01) and delay of phases of LP and PY firing. These results indicate that I(A) and I(h) play important roles in regulating pyloric rhythms in crayfish STG.

Do fibromyalgia patients use active pain management strategies? A cohort study.

PubMed

Gauffin, Jarno; Hankama, Tiina; Hannonen, Pekka; Kautiainen, Hannu; Pohjolainen, Timo; Haanpää, Maija

2013-05-01

The aim of this study was to examine the types of pain management strategies used by patients with fibromyalgia. A total of 158 patients with primary fibromyalgia attended a clinical visit to confirm the diagnosis. They completed 3 questionnaires: (i) a self-made questionnaire, (ii) Beck Depression Inventory IA (BDI IA), and (iii) Finnish version of Fibromyalgia Impact Questionnaire. The self-made questionnaire included questions about: intensity of current pain; general well-being; pain management strategies, including pain medications; efficacy of the pain management methods; current health problems other than fibromyalgia. The pain management strategies were subcategorized (e.g., physical exercise, massage and heat treatment). The strategies were also divided into active and passive types. The most frequently reported pain management strategies were physical exercise (54%), physical therapy (32%) and cold treatment (27%). The use of active pain management strategies, BDI IA < 10 points and age were independent predictors of the reported pain management efficacy. Patients who used active pain management strategies reported better efficacy with the BDI IA score ≥ 10 points. Active pain management strategies are most efficacious for fibromyalgia patients, regardless of the severity of fibromyalgia or optional comorbid depression.

Photometric and Spectroscopic Observations of SN 2012dn, a Super-Chandra Candidate Type-Ia Supernova

NASA Astrophysics Data System (ADS)

Parrent, Jerod T.; Transient Factory, Palomar; Cumbres Observatory Global Telescope Network, Las

2013-01-01

Currently, there is no singular standard model picture of type-Ia supernovae (SNe Ia) with a parameter-space of predictions that overlap the observed, diverse array of SN Ia properties. The same can be said for the super-luminous versions of SNe Ia, those thought to originate from up to 2.4 solar mass progenitor systems. To make matters worse, we remain in the dark-ages of astronomy regarding the interpretation of their observed spectra. In short, line-blending due to resonant line-scattering alone prevents making clear the compositional makeup of the outermost ejected layers. Since simulations of violent merger and single degenerate scenarios are both able to roughly reproduce spectroscopic observations, the direct mapping of the ejecta via spectrum synthesis measurements is of high importance. For example, with the closest SN Ia to date, SN 2011fe, we were able to map (in velocity space) the composition of the outer layers of ejecta. We did this by evolving simple P-Cygni-blends of synthetic spectra over the course of the first month (post-explosion), with an average of 1.8 days between observations by which to compare. As a result, SN 2011fe gave a clearer picture of the compositional structure of a ''normal'' SN Ia. We now have another chance to put this measure of SN Ia diversity into practice with the discovery of a brighter than normal southern hemisphere object, SN 2012dn. Here we present g-, r-, and i-band photometric observations obtained at Faulkes Telescope South, as well as optical time-series spectra from Gemini-North, Gemini-South, SALT, and MMT facilities. With 19 spectroscopic observations spanning its first month, post-explosion, we are able to measure the relative velocities of the periodic table in the outermost layers of ejected material. This serves as a means for distinguishing the origin of SNe Ia and their various forms.

Fitting and Phenomenology in Type IA Supernova Cosmology: Generalized Likelihood Analyses for Multiple Evolving Populations and Observations of Near-Infrared Lightcurves Including Host Galaxy Properties

NASA Astrophysics Data System (ADS)

Ponder, Kara A.

In the late 1990s, Type Ia supernovae (SNeIa) led to the discovery that the Universe is expanding at an accelerating rate due to dark energy. Since then, many different tracers of acceleration have been used to characterize dark energy, but the source of cosmic acceleration has remained a mystery. To better understand dark energy, future surveys such as the ground-based Large Synoptic Survey Telescope and the space-based Wide-Field Infrared Survey Telescope will collect thousands of SNeIa to use as a primary dark energy probe. These large surveys will be systematics limited, which makes it imperative for our insight regarding systematics to dramatically increase over the next decade for SNeIa to continue to contribute to precision cosmology. I approach this problem by improving statistical methods in the likelihood analysis and collecting near infrared (NIR) SNeIa with their host galaxies to improve the nearby data set and search for additional systematics. Using more statistically robust methods to account for systematics within the likelihood function can increase accuracy in cosmological parameters with a minimal precision loss. Though a sample of at least 10,000 SNeIa is necessary to confirm multiple populations of SNeIa, the bias in cosmology is ˜ 2 sigma with only 2,500 SNeIa. This work focused on an example systematic (host galaxy correlations), but it can be generalized for any systematic that can be represented by a distribution of multiple Gaussians. The SweetSpot survey gathered 114 low-redshift, NIR SNeIa that will act as a crucial anchor sample for the future high redshift surveys. NIR observations are not as affected by dust contamination, which may lead to increased understanding of systematics seen in optical wavelengths. We obtained spatially resolved spectra for 32 SweetSpot host galaxies to test for local host galaxy correlations. For the first time, we probe global host galaxy correlations with NIR brightnesses from the current literature sample of SNeIa with host galaxy data from publicly available catalogs. We find inconclusive evidence that more massive galaxies host SNeIa that are brighter in the NIR than SNeIa hosted in less massive galaxies.

Reconstruction of ionic currents in a molluscan photoreceptor.

PubMed Central

Sakakibara, M.; Ikeno, H.; Usui, S.; Collin, C.; Alkon, D. L.

1993-01-01

Two-microelectrode voltage-clamp measurements were made to determine the kinetics and voltage dependence of ionic currents across the soma membrane of the Hermissenda type B photoreceptor. The voltage-dependent outward potassium currents, IA and ICa(2+)-K+, the inward voltage-dependent calcium current, ICa2+ and the light-induced current, IIgt, were then described with Hodgkin-Huxley-type equations. The fast-activating and inactivating potassium current, IA, was described by the equation; IA(t) = gA(max)(ma infinity[1-exp(-t/tau ma)])3 x (ha infinity [1-exp(-t/tau ha)] + exp(-t/tau ha)) (Vm-EK), where the parameters ma infinity, ha infinity, tau ma, and tau ha are functions of membrane potential, Vm, and ma infinity and ha infinity are steady-state activation and inactivation parameters. Similarly, the calcium-dependent outward potassium current, ICa(2+)-K+, was described by the equation, ICa(2+)-K+ (t) = gc(max)(mc infinity(VC)(1-exp[-t/tau mc (VC)]))pc (hc infinity(VC) [1-exp(-t/tau hc)] + exp(-t/tau hc(VC)])pc(VC-EK). In high external potassium, ICa(2+)-K+ could be measured in approximate isolation from other currents as a voltage-dependent inward tail current following a depolarizing command pulse from a holding potential of -60 mV. A voltage-dependent inward calcium current across the type B soma membrane, ICa2+, activated rapidly, showed little inactivation, and was described by the equation: ICa2+ = gCa(max) [1 + exp](-Vm-5)/7]-1 (Vm-ECa), where gCa(max) was 0.5 microS. The light-induced current with both fast and slow phases was described by: IIgt(t) = IIgt1 + IIgt2 + IIgt3, IIgti = gIgti [1-exp(- ton/tau mi)] exp(-ton/tau hi)(Vm-EIgti) (i = 1, 2). For i = 3, /Igt(t) = gigt3m33h3(Vm - Eigt3)exp(-ton/Ton) x exp(-tfoff/t Off). Based on these reconstructions of ionic currents, learning-induced enhancement of the long lasting depolarization (LLD) of the photoreceptor'slight response was shown to arise from progressive inactivation of /A, lca2+ -K+, and lCa2+. PMID:8369456

Constraints on the holographic dark energy model via type Ia supernovae, baryon acoustic oscillation, and WMAP7

NASA Astrophysics Data System (ADS)

Xu, Lixin

2012-06-01

In this paper, the holographic dark energy model, where the future event horizon is taken as an IR cutoff, is confronted by using currently available cosmic observational data sets which include type Ia supernovae, baryon acoustic oscillation, and cosmic microwave background radiation from full information of WMAP 7-yr data. Via the Markov chain Monte Carlo method, we obtain the values of model parameter c=0.696-0.0737-0.132-0.190+0.0736+0.159+0.264 with 1, 2, 3σ regions. Therefore, one can conclude that at at least 3σ level the future Universe will be dominated by phantom-like dark energy. It is not consistent with positive energy condition, however this condition must be satisfied to derive the holographic bound. It implies that the current cosmic observational data points disfavor the holographic dark energy model.

Measurement of Ωm, ΩΛ from a Blind Analysis of Type Ia Supernovae with CMAGIC: Using Color Information to Verify the Acceleration of the Universe

NASA Astrophysics Data System (ADS)

Conley, A.; Goldhaber, G.; Wang, L.; Aldering, G.; Amanullah, R.; Commins, E. D.; Fadeyev, V.; Folatelli, G.; Garavini, G.; Gibbons, R.; Goobar, A.; Groom, D. E.; Hook, I.; Howell, D. A.; Kim, A. G.; Knop, R. A.; Kowalski, M.; Kuznetsova, N.; Lidman, C.; Nobili, S.; Nugent, P. E.; Pain, R.; Perlmutter, S.; Smith, E.; Spadafora, A. L.; Stanishev, V.; Strovink, M.; Thomas, R. C.; Wood-Vasey, W. M.; Supernova Cosmology Project

2006-06-01

We present measurements of Ωm and ΩΛ from a blind analysis of 21 high-redshift supernovae using a new technique (CMAGIC) for fitting the multicolor light curves of Type Ia supernovae, first introduced by Wang and coworkers. CMAGIC takes advantage of the remarkably simple behavior of Type Ia supernovae on color-magnitude diagrams and has several advantages over current techniques based on maximum magnitudes. Among these are a reduced sensitivity to host galaxy dust extinction, a shallower luminosity-width relation, and the relative simplicity of the fitting procedure. This allows us to provide a cross-check of previous supernova cosmology results, despite the fact that current data sets were not observed in a manner optimized for CMAGIC. We describe the details of our novel blindness procedure, which is designed to prevent experimenter bias. The data are broadly consistent with the picture of an accelerating universe and agree with a flat universe within 1.7 σ, including systematics. We also compare the CMAGIC results directly with those of a maximum magnitude fit to the same supernovae, finding that CMAGIC favors more acceleration at the 1.6 σ level, including systematics and the correlation between the two measurements. A fit for w assuming a flat universe yields a value that is consistent with a cosmological constant within 1.2 σ.

Successful Aortic Banding for Type IA Endoleak Due to Neck Dilatation after Endovascular Abdominal Aortic Aneurysm Repair: Case Report.

PubMed

Tashima, Yasushi; Tamai, Koichi; Shirasugi, Takehiro; Sato, Kenichiro; Yamamoto, Takahiro; Imamura, Yusuke; Yamaguchi, Atsushi; Adachi, Hideo; Kobinata, Toshiyuki

2017-09-25

A 69-year-old man with a type IA endoleak that developed approximately 21 months after endovascular abdominal aortic aneurysm repair (EVAR) of a 46 mm diameter aneurysm was referred to our department. He had impaired renal function, Parkinson's disease, and previous cerebral infarction. Computed tomography angiography showed a type IA endoleak with neck dilatation and that the aneurysm had grown to 60 mm in diameter. We decided to perform aortic banding. The type IA endoleak disappeared after banding and the patient was discharged on postoperative day 10. Aortic banding may be effective for type IA endoleak after EVAR and less invasive for high-risk patients in particular.

Intimate partner violence and repeat induced abortion in Italy: A cross sectional study.

PubMed

Citernesi, Angela; Dubini, Valeria; Uglietti, Anna; Ricci, Elena; Cipriani, Sonia; Parazzini, Fabio

2015-01-01

To investigate the impact of intimate partner violence (IPV) on the risk of repeat induced abortion (RIA), we compared IPV history among women with and without previous induced abortion (IA). All consecutive women aged 18 years or more requiring IA in 12 Italian abortion clinics were eligible for inclusion in the study. They were asked to fill in an anonymous, self-developed questionnaire assessing sociodemographic data and their history of different types of violence and related risk factors. The analysis included 1030 women, 624 (60.6%) of whom reported a previous IA. Past or current IPV was reported by 19.3%: 7.0% reported sexual violence, 11.3% physical abuse and 12.1% psychological abuse. Past or current IPV was reported by 22.3% of women with RIA and 14.8% of those undergoing their first IA (adjusted odds ratio 1.57, 95% confidence interval 1.07-2.30; p = 0.02). When we considered sexual, psychological and physical abuse separately, we found that any kind of abuse was more frequent in women with RIA than in women with no previous IA. This study underlines the impact of IPV on the risk of RIA and suggests the need for screening for IPV among women requiring abortion, in order to identify women at risk of RIA and to improve their general and reproductive health.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Escamilla-Rivera, Celia; Lazkoz, Ruth; Salzano, Vincenzo

Using real and synthetic Type Ia SNe (SNeIa) and baryon acoustic oscillations (BAO) data representing current observations forecasts, this paper investigates the tension between those probes in the dark energy equation of state (EoS) reconstruction considering the well known CPL model and Wang's low correlation reformulation. In particular, here we present simulations of BAO data from both the the radial and transverse directions. We also explore the influence of priors on Ω{sub m} and Ω{sub b} on the tension issue, by considering 1σ deviations in either one or both of them. Our results indicate that for some priors there ismore » no tension between a single dataset (either SNeIa or BAO) and their combination (SNeIa+BAO). Our criterion to discern the existence of tension (σ-distance) is also useful to establish which is the dataset with most constraining power; in this respect SNeIa and BAO data switch roles when current and future data are considered, as forecasts predict and spectacular quality improvement on BAO data. We also find that the results on the tension are blind to the way the CPL model is addressed: there is a perfect match between the original formulation and that by the correlation optimized proposed in Wang (2008), but the errors on the parameters are much narrower in all cases of our exhaustive exploration, thus serving the purpose of stressing the convenience of this reparametrization.« less

Observational Constraints on the Nature of the Dark Energy: First Cosmological Results From the ESSENCE Supernova Survey

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wood-Vasey, W.Michael; Miknaitis, G.; Stubbs, C.W.

We present constraints on the dark energy equation-of-state parameter, w = P/({rho}c{sup 2}), using 60 Type Ia supernovae (SNe Ia) from the ESSENCE supernova survey. We derive a set of constraints on the nature of the dark energy assuming a flat Universe. By including constraints on ({Omega}{sub M}, w) from baryon acoustic oscillations, we obtain a value for a static equation-of-state parameter w = -1.05{sub -0.12}{sup +0.13} (stat 1{sigma}) {+-} 0.13 (sys) and {Omega}{sub M} = 0.274{sub -0.020}{sup +0.033} (stat 1{sigma}) with a best-fit {chi}{sup 2}/DoF of 0.96. These results are consistent with those reported by the Super-Nova Legacy Surveymore » in a similar program measuring supernova distances and redshifts. We evaluate sources of systematic error that afflict supernova observations and present Monte Carlo simulations that explore these effects. Currently, the largest systematic currently with the potential to affect our measurements is the treatment of extinction due to dust in the supernova host galaxies. Combining our set of ESSENCE SNe Ia with the SuperNova Legacy Survey SNe Ia, we obtain a joint constraint of w = -1.07{sub -0.09}{sup +0.09} (stat 1{sigma}) {+-} 0.13 (sys), {Omega}{sub M} = 0.267{sub -0.018}{sup +0.028} (stat 1{sigma}) with a best-fit {chi}{sup 2}/DoF of 0.91. The current SNe Ia data are fully consistent with a cosmological constant.« less

Dark Matter Ignition of Type Ia Supernovae.

PubMed

Bramante, Joseph

2015-10-02

Recent studies of low redshift type Ia supernovae (SN Ia) indicate that half explode from less than Chandrasekhar mass white dwarfs, implying ignition must proceed from something besides the canonical criticality of Chandrasekhar mass SN Ia progenitors. We show that 1-100 PeV mass asymmetric dark matter, with imminently detectable nucleon scattering interactions, can accumulate to the point of self-gravitation in a white dwarf and collapse, shedding gravitational potential energy by scattering off nuclei, thereby heating the white dwarf and igniting the flame front that precedes SN Ia. We combine data on SN Ia masses with data on the ages of SN Ia-adjacent stars. This combination reveals a 2.8σ inverse correlation between SN Ia masses and ignition ages, which could result from increased capture of dark matter in 1.4 vs 1.1 solar mass white dwarfs. Future studies of SN Ia in galactic centers will provide additional tests of dark-matter-induced type Ia ignition. Remarkably, both bosonic and fermionic SN Ia-igniting dark matter also resolve the missing pulsar problem by forming black holes in ≳10  Myr old pulsars at the center of the Milky Way.

Relationships between major epitopes of the IA-2 autoantigen in Type 1 diabetes: Implications for determinant spreading.

PubMed

McLaughlin, Kerry A; Richardson, Carolyn C; Williams, Stefan; Bonifacio, Ezio; Morgan, Diana; Feltbower, Richard G; Powell, Michael; Rees Smith, Bernard; Furmaniak, Jadwiga; Christie, Michael R

2015-10-01

Diversification of autoimmunity to islet autoantigens is critical for progression to Type 1 diabetes. B-cells participate in diversification by modifying antigen processing, thereby influencing which peptides are presented to T-cells. In Type 1 diabetes, JM antibodies are associated with T-cell responses to PTP domain peptides. We investigated whether this is the consequence of close structural alignment of JM and PTP domain determinants on IA-2. Fab fragments of IA-2 antibodies with epitopes mapped to the JM domain blocked IA-2 binding of antibodies that recognise epitopes in the IA-2 PTP domain. Peptides from both the JM and PTP domains were protected from degradation during proteolysis of JM antibody:IA-2 complexes and included those representing major T-cell determinants in Type 1 diabetes. The results demonstrate close structural relationships between JM and PTP domain epitopes on IA-2. Stabilisation of PTP domain peptides during proteolysis in JM-specific B-cells may explain determinant spreading in IA-2 autoimmunity. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

THE TYPE Ia SUPERNOVA RATE IN RADIO AND INFRARED GALAXIES FROM THE CANADA-FRANCE-HAWAII TELESCOPE SUPERNOVA LEGACY SURVEY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Graham, M. L.; Pritchet, C. J.; Balam, D.

2010-02-15

We have combined the large SN Ia database of the Canada-France-Hawaii Telescope Supernova Legacy Survey and catalogs of galaxies with photometric redshifts, Very Large Array 1.4 GHz radio sources, and Spitzer infrared sources. We present eight SNe Ia in early-type host galaxies which have counterparts in the radio and infrared source catalogs. We find the SN Ia rate in subsets of radio and infrared early-type galaxies is {approx}1-5 times the rate in all early-type galaxies, and that any enhancement is always {approx}<2{sigma}. Rates in these subsets are consistent with predictions of the two-component 'A+B' SN Ia rate model. Since infraredmore » properties of radio SN Ia hosts indicate dust-obscured star formation, we incorporate infrared star formation rates into the 'A+B' model. We also show the properties of SNe Ia in radio and infrared galaxies suggest the hosts contain dust and support a continuum of delay time distributions (DTDs) for SNe Ia, although other DTDs cannot be ruled out based on our data.« less

A review of direct numerical simulations of astrophysical detonations and their implications

DOE PAGES

Parete-Koon, Suzanne T.; Smith, Christopher R.; Papatheodore, Thomas L.; ...

2013-04-11

Multi-dimensional direct numerical simulations (DNS) of astrophysical detonations in degenerate matter have revealed that the nuclear burning is typically characterized by cellular structure caused by transverse instabilities in the detonation front. Type Ia supernova modelers often use one- dimensional DNS of detonations as inputs or constraints for their whole star simulations. While these one-dimensional studies are useful tools, the true nature of the detonation is multi-dimensional. The multi-dimensional structure of the burning influences the speed, stability, and the composition of the detonation and its burning products, and therefore, could have an impact on the spectra of Type Ia supernovae. Considerablemore » effort has been expended modeling Type Ia supernovae at densities above 1x10 7 g∙cm -3 where the complexities of turbulent burning dominate the flame propagation. However, most full star models turn the nuclear burning schemes off when the density falls below 1x10 7 g∙cm -3 and distributed burning begins. The deflagration to detonation transition (DDT) is believed to occur at just these densities and consequently they are the densities important for studying the properties of the subsequent detonation. In conclusion, this work reviews the status of DNS studies of detonations and their possible implications for Type Ia supernova models. It will cover the development of Detonation theory from the first simple Chapman-Jouguet (CJ) detonation models to the current models based on the time-dependent, compressible, reactive flow Euler equations of fluid dynamics.« less

Improved Dark Energy Constraints From ~ 100 New CfA Supernova Type Ia Light Curves

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hicken, Malcolm; /Harvard-Smithsonian Ctr. Astrophys. /Harvard U.; Wood-Vasey, W.Michael

2012-04-06

We combine the CfA3 supernovae Type Ia (SN Ia) sample with samples from the literature to calculate improved constraints on the dark energy equation of state parameter, w. The CfA3 sample is added to the Union set of Kowalski et al. to form the Constitution set and, combined with a BAO prior, produces 1 + w = 0.013{sub -0.068}{sup +0.066} (0.11 syst), consistent with the cosmological constant. The CfA3 addition makes the cosmologically useful sample of nearby SN Ia between 2.6 and 2.9 times larger than before, reducing the statistical uncertainty to the point where systematics play the largest role.more » We use four light-curve fitters to test for systematic differences: SALT, SALT2, MLCS2k2 (R{sub V} = 3.1), and MLCS2k2 (R{sub V} = 1.7). SALT produces high-redshift Hubble residuals with systematic trends versus color and larger scatter than MLCS2k2. MLCS2k2 overestimates the intrinsic luminosity of SN Ia with 0.7 < {Delta} < 1.2. MLCS2k2 with R{sub V} = 3.1 overestimates host-galaxy extinction while R{sub V} {approx} 1.7 does not. Our investigation is consistent with no Hubble bubble. We also find that, after light-curve correction, SN Ia in Scd/Sd/Irr hosts are intrinsically fainter than those in E/S0 hosts by 2{sigma}, suggesting that they may come from different populations. We also find that SN Ia in Scd/Sd/Irr hosts have low scatter (0.1 mag) and reddening. Current systematic errors can be reduced by improving SN Ia photometric accuracy, by including the CfA3 sample to retrain light-curve fitters, by combining optical SN Ia photometry with near-infrared photometry to understand host-galaxy extinction, and by determining if different environments give rise to different intrinsic SN Ia luminosity after correction for light-curve shape and color.« less

IMPROVED DARK ENERGY CONSTRAINTS FROM {approx}100 NEW CfA SUPERNOVA TYPE Ia LIGHT CURVES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hicken, Malcolm; Challis, Peter; Kirshner, Robert P.

2009-08-01

We combine the CfA3 supernovae Type Ia (SN Ia) sample with samples from the literature to calculate improved constraints on the dark energy equation of state parameter, w. The CfA3 sample is added to the Union set of Kowalski et al. to form the Constitution set and, combined with a BAO prior, produces 1 + w = 0.013{sup +0.066} {sub -0.068} (0.11 syst), consistent with the cosmological constant. The CfA3 addition makes the cosmologically useful sample of nearby SN Ia between 2.6 and 2.9 times larger than before, reducing the statistical uncertainty to the point where systematics play the largestmore » role. We use four light-curve fitters to test for systematic differences: SALT, SALT2, MLCS2k2 (R{sub V} = 3.1), and MLCS2k2 (R{sub V} = 1.7). SALT produces high-redshift Hubble residuals with systematic trends versus color and larger scatter than MLCS2k2. MLCS2k2 overestimates the intrinsic luminosity of SN Ia with 0.7 < {delta} < 1.2. MLCS2k2 with R{sub V} = 3.1 overestimates host-galaxy extinction while R{sub V} {approx} 1.7 does not. Our investigation is consistent with no Hubble bubble. We also find that, after light-curve correction, SN Ia in Scd/Sd/Irr hosts are intrinsically fainter than those in E/S0 hosts by 2{sigma}, suggesting that they may come from different populations. We also find that SN Ia in Scd/Sd/Irr hosts have low scatter (0.1 mag) and reddening. Current systematic errors can be reduced by improving SN Ia photometric accuracy, by including the CfA3 sample to retrain light-curve fitters, by combining optical SN Ia photometry with near-infrared photometry to understand host-galaxy extinction, and by determining if different environments give rise to different intrinsic SN Ia luminosity after correction for light-curve shape and color.« less

Absolute Distances to Nearby Type Ia Supernovae via Light Curve Fitting Methods

NASA Astrophysics Data System (ADS)

Vinkó, J.; Ordasi, A.; Szalai, T.; Sárneczky, K.; Bányai, E.; Bíró, I. B.; Borkovits, T.; Hegedüs, T.; Hodosán, G.; Kelemen, J.; Klagyivik, P.; Kriskovics, L.; Kun, E.; Marion, G. H.; Marschalkó, G.; Molnár, L.; Nagy, A. P.; Pál, A.; Silverman, J. M.; Szakáts, R.; Szegedi-Elek, E.; Székely, P.; Szing, A.; Vida, K.; Wheeler, J. C.

2018-06-01

We present a comparative study of absolute distances to a sample of very nearby, bright Type Ia supernovae (SNe) derived from high cadence, high signal-to-noise, multi-band photometric data. Our sample consists of four SNe: 2012cg, 2012ht, 2013dy and 2014J. We present new homogeneous, high-cadence photometric data in Johnson–Cousins BVRI and Sloan g‧r‧i‧z‧ bands taken from two sites (Piszkesteto and Baja, Hungary), and the light curves are analyzed with publicly available light curve fitters (MLCS2k2, SNooPy2 and SALT2.4). When comparing the best-fit parameters provided by the different codes, it is found that the distance moduli of moderately reddened SNe Ia agree within ≲0.2 mag, and the agreement is even better (≲0.1 mag) for the highest signal-to-noise BVRI data. For the highly reddened SN 2014J the dispersion of the inferred distance moduli is slightly higher. These SN-based distances are in good agreement with the Cepheid distances to their host galaxies. We conclude that the current state-of-the-art light curve fitters for Type Ia SNe can provide consistent absolute distance moduli having less than ∼0.1–0.2 mag uncertainty for nearby SNe. Still, there is room for future improvements to reach the desired ∼0.05 mag accuracy in the absolute distance modulus.

"Type Ia Supernovae: Tools for Studying Dark Energy" Final Technical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Woosley, Stan; Kasen, Dan

2017-05-10

Final technical report for project "Type Ia Supernovae: Tools for the Study of Dark Energy" awarded jointly to scientists at the University of California, Santa Cruz and Berkeley, for computer modeling, theory and data analysis relevant to the use of Type Ia supernovae as standard candles for cosmology.

On the progenitors of Type Ia supernovae

NASA Astrophysics Data System (ADS)

Livio, Mario; Mazzali, Paolo

2018-03-01

We review all the models proposed for the progenitor systems of Type Ia supernovae and discuss the strengths and weaknesses of each scenario when confronted with observations. We show that all scenarios encounter at least a few serious difficulties, if taken to represent a comprehensive model for the progenitors of all Type Ia supernovae (SNe Ia). Consequently, we tentatively conclude that there is probably more than one channel leading SNe Ia. While the single-degenerate scenario (in which a single white dwarf accretes mass from a normal stellar companion) has been studied in some detail, the other scenarios will need a similar level of scrutiny before any firm conclusions can be drawn.

The repair of a type Ia endoleak following thoracic endovascular aortic repair using a stented elephant trunk procedure.

PubMed

Qi, Rui-Dong; Zhu, Jun-Ming; Liu, Yong-Min; Chen, Lei; Li, Cheng-Nan; Xing, Xiao-Yan; Sun, Li-Zhong

2018-04-01

Type Ia endoleaks are not uncommon complications that occur after thoracic endovascular aortic repair (TEVAR). Because aortic arch vessels prevent extension of the landing zone, it is very difficult to manipulate a type Ia endoleak using an extension cuff or stent-graft, especially when the aortic arch is involved. Here, we retrospectively review our experience of surgical treatment of type Ia endoleak after TEVAR using a stented elephant trunk procedure. From July 2010 to August 2016, we treated 17 patients diagnosed with a type Ia endoleak following TEVAR using stented elephant trunk procedure. The mean age of our patients was 52 ± 8 years. The mean interval between TEVAR and the open surgical repair was 38 ± 43 months. All cases of type Ia endoleak (100%) were repaired successfully. There were no in-hospital deaths. One case required reintubation and continuous renal replacement therapy due to renal failure; this patient recovered smoothly before discharge. One other patient suffered a stroke and renal failure and did not fully recover following discharge, or follow-up. During follow-up, there were 3 deaths. Acceptable results were obtained using a stented elephant trunk procedure in patients with a type Ia endoleak after TEVAR. This technique allowed us to repair the proximal aortic arch lesions, surgically correct the type Ia endoleak, and promote false lumen thrombosis in the distal aorta. Implantation of a stented elephant trunk, with or without a concomitant aortic arch procedure, is an alternative approach for this type of lesion. Copyright © 2017 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

Study of the influence of Type Ia supernovae environment on the Hubble diagram

NASA Astrophysics Data System (ADS)

Henne, Vincent

2016-06-01

The observational cosmology with distant Type Ia supernovae as standard candles claims that the Universe is in accelerated expansion, caused by a large fraction of dark energy. In this report we investigated SNe Ia environment, studying the impact of the nature of their host galaxies and their distance to the host galactic center on the Hubble diagram fitting. The supernovae used in the analysis were extracted from Joint-Light-curves-Analysis compilation of high-redshift and nearby supernovae. The analysis are based on the empirical fact that SN Ia luminosities depend on their light curve shapes and colors. No conclusive correlation between SN Ia light curve parameters and galocentric distance were identified. Concerning the host morphology, we showed that the stretch parameter of Type Ia supernovae is correlated with the host galaxy type. The supernovae with lower stretch mainly exploded in elliptical and lenticular galaxies. The studies show that into old star population and low dust environment, supernovae are fainter. We did not find any significant correlation between Type Ia supernovae color and host morphology. We confirm that supernova properties depend on their environment and propose to incorporate a host galaxy term into the Hubble diagram fit in the future cosmological analysis.

The Type Ia Supernova Color-Magnitude Relation and Host Galaxy Dust: A Simple Hierarchical Bayesian Model

NASA Astrophysics Data System (ADS)

Mandel, Kaisey; Scolnic, Daniel; Shariff, Hikmatali; Foley, Ryan; Kirshner, Robert

2017-01-01

Inferring peak optical absolute magnitudes of Type Ia supernovae (SN Ia) from distance-independent measures such as their light curve shapes and colors underpins the evidence for cosmic acceleration. SN Ia with broader, slower declining optical light curves are more luminous (“broader-brighter”) and those with redder colors are dimmer. But the “redder-dimmer” color-luminosity relation widely used in cosmological SN Ia analyses confounds its two separate physical origins. An intrinsic correlation arises from the physics of exploding white dwarfs, while interstellar dust in the host galaxy also makes SN Ia appear dimmer and redder. Conventional SN Ia cosmology analyses currently use a simplistic linear regression of magnitude versus color and light curve shape, which does not model intrinsic SN Ia variations and host galaxy dust as physically distinct effects, resulting in low color-magnitude slopes. We construct a probabilistic generative model for the dusty distribution of extinguished absolute magnitudes and apparent colors as the convolution of an intrinsic SN Ia color-magnitude distribution and a host galaxy dust reddening-extinction distribution. If the intrinsic color-magnitude (MB vs. B-V) slope βint differs from the host galaxy dust law RB, this convolution results in a specific curve of mean extinguished absolute magnitude vs. apparent color. The derivative of this curve smoothly transitions from βint in the blue tail to RB in the red tail of the apparent color distribution. The conventional linear fit approximates this effective curve near the average apparent color, resulting in an apparent slope βapp between βint and RB. We incorporate these effects into a hierarchical Bayesian statistical model for SN Ia light curve measurements, and analyze a dataset of SALT2 optical light curve fits of 277 nearby SN Ia at z < 0.10. The conventional linear fit obtains βapp ≈ 3. Our model finds a βint = 2.2 ± 0.3 and a distinct dust law of RB = 3.7 ± 0.3, consistent with the average for Milky Way dust, while correcting a systematic distance bias of ~0.10 mag in the tails of the apparent color distribution. This research is supported by NSF grants AST-156854, AST-1211196, and NASA grant NNX15AJ55G.

Select early type IA endoleaks after endovascular aneurysm repair will resolve without secondary intervention.

PubMed

O'Donnell, Thomas F X; Corey, Michael R; Deery, Sarah E; Tsougranis, Gregory; Maruthi, Rohit; Clouse, W Darrin; Cambria, Richard P; Conrad, Mark F

2018-01-01

Although it is traditionally considered ominous, the natural history of early proximal attachment site endoleaks (IA) after endovascular aneurysm repair (EVAR) is not well known. Our aim was to identify risk factors for persistent type IA endoleaks and to determine their effect on long-term outcomes after EVAR. All patients who underwent infrarenal EVAR at a single institution between 1998 and 2015 were identified. Preoperative axial imaging and intraoperative arteriograms were reviewed, and those patients with a type IA endoleak were further studied. Aneurysm features were characterized by two reviewers and were studied for predictors of persistent endoleaks at the conclusion of the case. Patient records and the Social Security Death Index were used to record 1-year and overall survival. We identified 1484 EVARs, 122 (8%) of which were complicated by a type IA endoleak on arteriography after graft deployment, with a median follow-up of 4 years. The majority of patients underwent additional ballooning of the proximal site (52 [43%]) or placement of an aortic cuff (47 [39%]); 30 patients (25%) received a Palmaz stent, and four patients were treated with coils or anchors. At case end, only 43 (35%) of the type IA endoleaks remained; at 1 month, only 16 endoleaks persisted (13%), and only six persisted at 1 year (6%). In multivariable analysis, the only independent predictor of persistence of type IA endoleak at the conclusion of the case was the presence of extensive neck calcifications (odds ratio [OR], 9.9; 95% confidence interval [CI], 1.4-67.9; P = .02). Thirteen patients (11%) underwent reintervention for type IA endoleaks, with a time frame ranging from 3 days postoperatively to 11 years. There were three patients (2.4%) who experienced aneurysm rupture. Postoperative type IA endoleak was associated with lower survival at 1 year (79% vs 91%; relative risk, 2.5; 95% CI, 1.1-5.4; P = .02), but it did not affect long-term survival (log-rank, P = .45). Both an increase in aneurysm sac size and failure of the endoleak to resolve by case end were independent predictors of a need for reintervention (growth: OR, 8.3; 95% CI, 2.2-31.6; P < .01; persistent endoleak: OR, 7.6; 95% CI, 1.8-31.5; P < .01). A persistent type IA endoleak was not independently associated with an increase in sac size on surveillance imaging (P = .28). Aneurysm rupture secondary to persistent type IA endoleak is rare, and most will resolve within 1 year. Extensive neck calcification is the only independent predictor of persistent type IA endoleak, and an increase in sac size warrants reintervention. These data suggest that select early persistent type IA endoleaks can be safely observed. Copyright © 2017 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Mapping of epitopes for autoantibodies to the type 1 diabetes autoantigen IA-2 by peptide phage display and molecular modeling: overlap of antibody and T cell determinants.

PubMed

Dromey, James A; Weenink, Sarah M; Peters, Günther H; Endl, Josef; Tighe, Patrick J; Todd, Ian; Christie, Michael R

2004-04-01

IA-2 is a major target of autoimmunity in type 1 diabetes. IA-2 responsive T cells recognize determinants within regions represented by amino acids 787-817 and 841-869 of the molecule. Epitopes for IA-2 autoantibodies are largely conformational and not well defined. In this study, we used peptide phage display and homology modeling to characterize the epitope of a monoclonal IA-2 Ab (96/3) from a human type 1 diabetic patient. This Ab competes for IA-2 binding with Abs from the majority of patients with type 1 diabetes and therefore binds a region close to common autoantibody epitopes. Alignment of peptides obtained after screening phage-displayed peptide libraries with purified 96/3 identified a consensus binding sequence of Asn-x-Glu-x-x-(aromatic)-x-x-Gly. The predicted surface on a three-dimensional homology model of the tyrosine phosphatase domain of IA-2 was analyzed for clusters of Asn, Glu, and aromatic residues and amino acids contributing to the epitope investigated using site-directed mutagenesis. Mutation of each of amino acids Asn(858), Glu(836), and Trp(799) reduced 96/3 Ab binding by >45%. Mutations of these residues also inhibited binding of serum autoantibodies from IA-2 Ab-positive type 1 diabetic patients. This study identifies a region commonly recognized by autoantibodies in type 1 diabetes that overlaps with dominant T cell determinants.

The upstream enhancer elements of the G6PC promoter are critical for optimal G6PC expression in murine glycogen storage disease type Ia.

PubMed

Lee, Young Mok; Pan, Chi-Jiunn; Koeberl, Dwight D; Mansfield, Brian C; Chou, Janice Y

2013-11-01

Glycogen storage disease type-Ia (GSD-Ia) patients deficient in glucose-6-phosphatase-α (G6Pase-α or G6PC) manifest impaired glucose homeostasis characterized by fasting hypoglycemia, growth retardation, hepatomegaly, nephromegaly, hyperlipidemia, hyperuricemia, and lactic acidemia. Two efficacious recombinant adeno-associated virus pseudotype 2/8 (rAAV8) vectors expressing human G6Pase-α have been independently developed. One is a single-stranded vector containing a 2864-bp of the G6PC promoter/enhancer (rAAV8-GPE) and the other is a double-stranded vector containing a shorter 382-bp minimal G6PC promoter/enhancer (rAAV8-miGPE). To identify the best construct, a direct comparison of the rAAV8-GPE and the rAAV8-miGPE vectors was initiated to determine the best vector to take forward into clinical trials. We show that the rAAV8-GPE vector directed significantly higher levels of hepatic G6Pase-α expression, achieved greater reduction in hepatic glycogen accumulation, and led to a better toleration of fasting in GSD-Ia mice than the rAAV8-miGPE vector. Our results indicated that additional control elements in the rAAV8-GPE vector outweigh the gains from the double-stranded rAAV8-miGPE transduction efficiency, and that the rAAV8-GPE vector is the current choice for clinical translation in human GSD-Ia. © 2013.

Immunoadsorption in Anti-GBM Glomerulonephritis: Case Report in a Child and Literature Review.

PubMed

Dorval, Guillaume; Lion, Mathilde; Guérin, Sophie; Krid, Saoussen; Galmiche-Rolland, Louise; Salomon, Rémi; Boyer, Olivia

2017-11-01

Antiglomerular basement membrane glomerulonephritis (anti-GBM GN) is a rare autoimmune disease that is characterized by rapidly progressive glomerulonephritis that may be associated with pulmonary hemorrhage. Anti-GBM GN is caused by autoantibodies (classically type G immunoglobulin) directed against the α3 subunit of type IV collagen. Without any appropriate treatment, the disease is generally fulminant, and patient and kidney survival is poor. The current guidelines recommend the use of plasma exchanges and immunosuppressive drugs. Immunoadsorption (IA) can remove pathogenic IgGs from the circulation and do not require plasma infusions, contrary to plasma exchanges. IA has seldom been used in adult patients with good tolerance and efficiency. We report herein the first pediatric case successfully treated with IA combined with immunosuppressive drugs in a 7-year-old girl who presented acute kidney injury (estimated glomerular filtration rate 38 mL/minute/1.73 m 2 ). A kidney biopsy revealed numerous >80% glomerular crescents and linear IgG deposits along the glomerular basement membrane. Ten IA sessions led to rapid and sustained clearance of autoantibodies and improvement of kidney function until 21 months after onset (glomerular filtration rate 87 mL/minute/1.73 m 2 ). No adverse effect was noted. This report adds to the growing body of evidence suggesting IA as a therapeutic alternative to plasma exchanges in anti-GBM GN. The other 27 published pediatric cases of anti-GBM GN are reviewed. Copyright © 2017 by the American Academy of Pediatrics.

Association of female sex and heart rate with increased arterial stiffness in patients with type 2 diabetes mellitus

PubMed Central

Kang, Min-Kyung; Yu, Jae Myung; Chun, Kwang Jin; Choi, Jaehuk; Choi, Seonghoon; Lee, Namho; Cho, Jung Rae

2017-01-01

Objective: This study aimed to evaluate the factors associated with increased arterial stiffness (IAS) measured by pulse wave velocity (PWV) and its clinical implications in patients with type 2 diabetes mellitus (DM). Methods: This was an observational, cross-sectional study. The ankle–brachial PWV was used to measure arterial stiffness, and 310 patients (mean age, 49±9 years; 180 men) with type 2 DM were divided into two groups according to the results of PWV: Group 1 (IAS; n=214) and Group 2 (normal arterial stiffness; n=96). Results: Patients in Group 1 were predominantly females (48% vs. 28%, p=0.001) and showed higher blood pressure and faster heart rate (HR). The glomerular filtration rate was lower and the urine microalbumin level was higher in patients with IAS. In multiple regression analysis, female sex and faster HR were independently associated with IAS. In subgroup analysis among female patients, prior stroke was more common in patients with IAS, and faster HR and increased postprandial 2-h C-peptide level were independently associated with IAS. Conclusion: Female sex and faster HR were independently associated with IAS in patients with type 2 DM. In a subgroup analysis among female patients, prior stroke was more common in patients with IAS, and faster HR and elevated postprandial 2-h C-peptide level were found to be independently associated with IAS. PMID:29145217

SN 1991T - Gamma-Ray Observatory's first supernova?

NASA Technical Reports Server (NTRS)

Burrows, Adam; Shankar, Anurag; Van Riper, Kenneth A.

1991-01-01

Consideration is given to the explosion of the Type Ia supernova SN 1991T in the nearby galaxy NGC 4527 detected in gamma-ray lines by the recently launched GRO. The dominant gamma-line and continuum features of the new 'delayed detonation' model FDEFA1 are calculated and compared to those for standard deflagration models W7 and cdtg7. It is shown that there are many useful hard photon discriminants of the Type Ia explosion mechanism that can, in principle, be detected by the OSSE and COMPTEL instruments on the GRO. Either SN 1991T, if bright enough, or one of the several Type Ia supernovae expected to be within the GRO's range during its active life, may make it possible to settle the detonation/deflagration debate, verify the generic thermonuclear white dwarf model of Type Ia explosions, and calibrate the Type Ia B(max)/847 keV line flux ratio.

Search for Type Ia supernova NUV-optical subclasses

NASA Astrophysics Data System (ADS)

Cinabro, David; Scolnic, Daniel; Kessler, Richard; Li, Ashley; Miller, Jake

2017-04-01

In response to a recently reported observation of evidence for two classes of Type Ia supernovae (SNe Ia) distinguished by their brightness in the rest-frame near-ultraviolet (NUV), we search for the phenomenon in publicly available light-curve data. We use the SNANA supernova analysis package to simulate SN Ia light curves in the Sloan Digital Sky Survey (SDSS) Supernova Search and the Supernova Legacy Survey (SNLS) with a model of two distinct ultraviolet classes of SNe Ia and a conventional model with a single broad distribution of SN-Ia ultraviolet brightnesses. We compare simulated distributions of rest-frame colours with these two models to those observed in 158 SNe Ia in the SDSS and SNLS data. The SNLS sample of 99 SNe Ia is in clearly better agreement with a model with one class of SN Ia light curves and shows no evidence for distinct NUV sub-classes. The SDSS sample of 59 SNe Ia with poorer colour resolution does not distinguish between the two models.

The Diffuse Gamma-Ray Background from Type Ia Supernovae

NASA Technical Reports Server (NTRS)

Lien, Amy; Fields, Brian D.

2012-01-01

The origin of the diffuse extragalactic gamma-ray background (EGB) has been intensively studied but remains unsettled. Current popular source candidates include unresolved star-forming galaxies, starburst galaxies, and blazars. In this paper we calculate the EGB contribution from the interactions of cosmic rays accelerated by Type Ia supernovae, extending earlier work which only included core-collapse supernovae. We consider Type Ia events in star-forming galaxies, but also in quiescent galaxies that lack star formation. In the case of star-forming galaxies, consistently including Type Ia events makes little change to the star-forming EGB prediction, so long as both supernova types have the same cosmic-ray acceleration efficiencies in star-forming galaxies. Thus our updated EGB estimate continues to show that star-forming galaxies can represent a substantial portion of the signal measured by Fermi. In the case of quiescent galaxies, conversely, we find a wide range of possibilities for the EGB contribution. The dominant uncertainty we investigated comes from the mass in hot gas in these objects, which provides targets for cosmic rays: total gas masses are as yet poorly known, particularly at larger radii. Additionally, the EGB estimation is very sensitive to the cosmic-ray acceleration efficiency and confinement, especially in quiescent galaxies. In the most optimistic allowed scenarios, quiescent galaxies can be an important source of the EGB. In this case, star-forming galaxies and quiescent galaxies together will dominate the EGB and leave little room for other contributions. If other sources, such as blazars, are found to have important contributions to the EGB, then either the gas mass or cosmic-ray content of quiescent galaxies must be significantly lower than in their star-forming counterparts. In any case, improved Fermi EGB measurements will provide important constraints on hot gas and cosmic rays in quiescent galaxies.

The Core Cysteines, (C909) of Islet Antigen-2 and (C945) of Islet Antigen-2β, Are Crucial to Autoantibody Binding in Type 1 Diabetes

PubMed Central

Elvers, Karen T.; Geoghegan, Ivey; Shoemark, Debbie K.; Lampasona, Vito; Bingley, Polly J.; Williams, Alistair J.K.

2013-01-01

Cysteines are thought integral to conformational epitopes of islet antigen-2 (IA-2) autoantibodies (IA-2A), possibly through disulfide bond formation. We therefore investigated which cysteines are critical to IA-2A binding in patients with newly diagnosed type 1 diabetes. All 10 cysteines in the intracellular domain of IA-2 were modified to serine by site-directed mutagenesis, and the effects of these changes on autoantibody binding in comparison with wild-type control were investigated by radiobinding assay. Mutation of the protein tyrosine phosphatase (PTP) core cysteine (C909) in IA-2 caused large reductions in autoantibody binding. In contrast, little or no reduction in binding was seen following substitution of the other cysteines. Modification of the core cysteine (C945) in IA-2β also greatly reduced autoantibody binding. Lysine substitution of glutamate-836 in IA-2 or glutamate-872 in IA-2β resulted in modest reductions in binding and identified a second epitope region. Binding to IA-2 PTP and IA-2β PTP was almost abolished by mutation of both the core cysteine and these glutamates. The core cysteine is key to the major PTP conformational epitope, but disulfide bonding contributes little to IA-2A epitope integrity. In most patients, at disease onset, >90% of antibodies binding to the PTP domain of IA-2 recognize just two epitope regions. PMID:22966073

A rationally designed peptide IA-2-P2 against type 1 diabetes in streptozotocin-induced diabetic mice.

PubMed

Shen, Lili; Lu, Shiping; Huang, Dongcheng; Li, Guoliang; Liu, Kunfeng; Cao, Rongyue; Zong, Li; Jin, Liang; Wu, Jie

2017-05-01

Recent studies have investigated the potential of type 1 diabetes mellitus-related autoantigens, such as heat shock protein 60, to induce immunological tolerance or to suppress the immune response. A functional 24-residue peptide derived from heat shock protein 60 (P277) has shown anti-type 1 diabetes mellitus potential in experimental animals and in clinical studies, but it also carries a potential atherogenic effect. In this study, we have modified P277 to retain an anti-type 1 diabetes mellitus effect and minimize the atherogenic potential by replacing the P277 B epitope with another diabetes-associated autoantigen, insulinoma antigen-2 (IA-2), to create the fusion peptide IA-2-P2. In streptozotocin-induced diabetic C57BL/6J mice, the IA-2-P2 peptide displayed similar anti-diabetic effects to the control P277 peptide. Also, the IA-2-P2 peptide did not show atherogenic activity in a rabbit model. Our findings indicate the potential of IA-2-P2 as a promising vaccine against type 1 diabetes mellitus.

Nearby Type Ia Supernova Follow-up at the Thacher Observatory

NASA Astrophysics Data System (ADS)

Swift, Jonathan; O'Neill, Katie; Kilpatrick, Charles; Foley, Ryan

2018-06-01

Type Ia supernovae (SN Ia) provide an effective way to study the expansion of the universe through analyses of their photometry and spectroscopy. The interpretation of high-redshift SN Ia is dependent on accurate characterization of nearby, low-redshift targets. To help build up samples of nearby SN Ia, the Thacher Observatory has begun a photometric follow-up program in 4 photometric bands. Here we present the observations and analysis of multi-band photometry for several recent supernovae as well as FLOYDS spectra from the Las Cumbres Observatory.

Characteristics of intracranial aneurysms in the else kröner-fresenius registry of autosomal dominant polycystic kidney disease.

PubMed

Neumann, Hartmut P H; Malinoc, Angelica; Bacher, Janina; Nabulsi, Zinaida; Ivanovas, Vera; Bruechle, Nadine Ortiz; Mader, Irina; Hoffmann, Michael M; Riegler, Peter; Kraemer-Guth, Annette; Burchardi, Christian; Schaeffner, Elke; Martin, Rodolfo S; Azurmendi, Pablo J; Zerres, Klaus; Jilg, Cordula; Eng, Charis; Gläsker, Sven

2012-01-01

Patients who harbor intracranial aneurysms (IAs) run a risk for aneurysm rupture and subsequent subarachnoid hemorrhage which frequently results in permanent deficits or death. Prophylactic treatment of unruptured aneurysms is possible and recommended depending on the size and location of the aneurysm as well as patient age and condition. IAs are major manifestations of autosomal dominant polycystic kidney disease (ADPKD). Current guidelines do not suggest surveillance of IAs in ADPKD except in the setting of family history if IA was known in any relative with ADPKD. Management of IAs in ADPKD is problematic because limited data exist from large studies. We established the Else Kröner-Fresenius Registry for ADPKD in Germany. Clinical data were assessed for age at diagnosis of IAs, stage of renal insufficiency, and number, location and size of IAs as well as family history of cerebral events. Patients with symptomatic or asymptomatic IAs were included. All patients with ADPKD-related IAs were offered mutation scanning of the susceptibility genes for ADPKD, the PKD1 and PKD2 genes. Of 463 eligible ADPKD patients from the population base of Germany, 32 (7%) were found to have IAs, diagnosed at the age of 2-71 years, 19 females and 13 males. Twenty (63%) of these 32 patients were symptomatic, whereas IAs were detected in an asymptomatic stage in 12 patients. IAs were multifocal in 12 and unifocal in 20 patients. In 26 patients (81%), IAs were diagnosed before end-stage renal failure. Twenty-five out of 27 unrelated index cases (93%) had no IAs or cerebral events documented in their relatives with ADPKD. In 16 unrelated index patients and 3 relatives, we detected germline mutations. The mutations were randomly distributed across the PKD1 gene in 14 and the PKD2 gene in 2 index cases. Questionnaires answered for 320/441 ADPKD patients without IAs revealed that only 45/320 (14%) had MR angiography. In ADPKD, rupture of IAs occurs frequently before the start of dialysis, is only infrequently associated with a family history of IAs or subarachnoid hemorrhage, and is associated with mutations either of the PKD1 or the PKD2 gene of any type. Screening for IAs is widely insufficiently performed, should not be restricted to families with a history of cerebral events and should be started before end-stage renal failure.

Personalizing Androgen Suppression for Prostate Cancer Using Mathematical Modeling.

PubMed

Hirata, Yoshito; Morino, Kai; Akakura, Koichiro; Higano, Celestia S; Aihara, Kazuyuki

2018-02-08

Using a dataset of 150 patients treated with intermittent androgen suppression (IAS) through a fixed treatment schedule, we retrospectively designed a personalized treatment schedule mathematically for each patient. We estimated 100 sets of parameter values for each patient by randomly resampling each patient's time points to take into account the uncertainty for observations of prostate specific antigen (PSA). Then, we identified 3 types and classified patients accordingly: in type (i), the relapse, namely the divergence of PSA, can be prevented by IAS; in type (ii), the relapse can be delayed by IAS later than by continuous androgen suppression (CAS); in type (iii) IAS was not beneficial and therefore CAS would have been more appropriate in the long run. Moreover, we obtained a treatment schedule of hormone therapy by minimizing the PSA of 3 years later in the worst case scenario among the 100 parameter sets by searching exhaustively all over the possible treatment schedules. If the most frequent type among 100 sets was type (i), the maximal PSA tended to be kept less than 100 ng/ml longer in IAS than in CAS, while there was no statistical difference for the other cases. Thus, mathematically personalized IAS should be studied prospectively.

The Evolution of the Type Ia Supernova Luminosity Function

NASA Astrophysics Data System (ADS)

Shen, Ken J.; Toonen, Silvia; Graur, Or

2017-12-01

Type Ia supernovae (SNe Ia) exhibit a wide diversity of peak luminosities and light curve shapes: the faintest SNe Ia are 10 times less luminous and evolve more rapidly than the brightest SNe Ia. Their differing characteristics also extend to their stellar age distributions, with fainter SNe Ia preferentially occurring in old stellar populations and vice versa. In this Letter, we quantify this SN Ia luminosity–stellar age connection using data from the Lick Observatory Supernova Search (LOSS). Our binary population synthesis calculations agree qualitatively with the observed trend in the > 1 {Gyr} old populations probed by LOSS if the majority of SNe Ia arise from prompt detonations of sub-Chandrasekhar-mass white dwarfs (WDs) in double WD systems. Under appropriate assumptions, we show that double WD systems with less massive primaries, which yield fainter SNe Ia, interact and explode at older ages than those with more massive primaries. We find that prompt detonations in double WD systems are capable of reproducing the observed evolution of the SN Ia luminosity function, a constraint that any SN Ia progenitor scenario must confront.

The Fate of Exploding White Dwarfs

NASA Astrophysics Data System (ADS)

Fisher, Robert

2018-01-01

Type Ia supernovae play an important role as standardizable candles for cosmology, providing one of the most important probes into the nature of dark energy. Yet, the nature of the stellar progenitors which give rise to Type Ia supernovae remains elusive. For decades, the leading model explaining Type Ia supernovae properties consisted of a white dwarf accreting to near the Chandrasekhar mass, in the single-degenerate channel. More recently, a variety of lines of evidence point instead towards merging binary white dwarfs, in the double-degenerate channel, as the progenitors of most Type Ia supernovae. In this talk, I will focus upon recent advances at the interface between observation and theory which will help crack the Type Ia progenitor problem. In particular, I will present new insights obtained from recent multidimensional numerical simulations of both the double-degenerate and single-degenerate channels which I have undertaken with my students and collaborators. I will discuss how new models and observations will help elucidate the long-standing mystery of Type supernovae.

Supernovae anisotropy power spectrum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghodsi, Hoda; Baghram, Shant; Habibi, Farhang, E-mail: h.ghodsi@mehr.sharif.ir, E-mail: baghram@sharif.edu, E-mail: habibi@lal.in2p3.fr

2017-10-01

We contribute another anisotropy study to this field of research using Type Ia supernovae (SNe Ia). In this work, we utilise the power spectrum calculation method and apply it to both the current SNe Ia data and simulation. Using the Union2.1 data set at all redshifts, we compare the spectrum of the residuals of the observed distance moduli to that expected from an isotropic universe affected by the Union2.1 observational uncertainties at low multipoles. Through this comparison we find a dipolar anisotropy with tension of less that 2σ towards l = 171° ± 21° and b = −26° ± 28°more » which is mainly induced by anisotropic spatial distribution of the SNe with z > 0.2 rather than being a cosmic effect. Furthermore, we find a tension of ∼ 4σ at ℓ = 4 between the two spectra. Our simulations are constructed with the characteristics of the upcoming surveys like the Large Synoptic Survey Telescope (LSST), which shall bring us the largest SNe Ia collection to date. We make predictions for the amplitude of a possible dipolar anisotropy that would be detectable by future SNe Ia surveys.« less

Distance measurements from supernovae and dark energy constraints

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang Yun

2009-12-15

Constraints on dark energy from current observational data are sensitive to how distances are measured from Type Ia supernova (SN Ia) data. We find that flux averaging of SNe Ia can be used to test the presence of unknown systematic uncertainties, and yield more robust distance measurements from SNe Ia. We have applied this approach to the nearby+SDSS+ESSENCE+SNLS+HST set of 288 SNe Ia, and the 'Constitution' set of 397 SNe Ia. Combining the SN Ia data with cosmic microwave background anisotropy data from Wilkinson Microwave Anisotropy Probe 5 yr observations, the Sloan Digital Sky Survey baryon acoustic oscillation measurements, themore » data of 69 gamma-ray bursts (GRBs) , and the Hubble constant measurement from the Hubble Space Telescope project SHOES, we measure the dark energy density function X(z){identical_to}{rho}{sub X}(z)/{rho}{sub X}(0) as a free function of redshift (assumed to be a constant at z>1 or z>1.5). Without the flux averaging of SNe Ia, the combined data using the Constitution set of SNe Ia seem to indicate a deviation from a cosmological constant at {approx}95% confidence level at 0 < or apporx. z < or approx. 0.8; they are consistent with a cosmological constant at {approx}68% confidence level when SNe Ia are flux averaged. The combined data using the nearby+SDSS+ESSENCE+SNLS+HST data set of SNe Ia are consistent with a cosmological constant at 68% confidence level with or without flux averaging of SNe Ia, and give dark energy constraints that are significantly more stringent than that using the Constitution set of SNe Ia. Assuming a flat Universe, dark energy is detected at >98% confidence level for z{<=}0.75 using the combined data with 288 SNe Ia from nearby+SDSS+ESSENCE+SNLS+HST, independent of the assumptions about X(z{>=}1). We quantify dark energy constraints without assuming a flat Universe using the dark energy figure of merit for both X(z) and a dark energy equation-of-state linear in the cosmic scale factor.« less

A longitudinal study of GAD65 and ICA512 autoantibodies during the progression to type 1 diabetes in Diabetes Prevention Trial-Type 1 (DPT-1) participants.

PubMed

Sosenko, Jay M; Skyler, Jay S; Palmer, Jerry P; Krischer, Jeffrey P; Cuthbertson, David; Yu, Liping; Schatz, Desmond A; Orban, Tihamer; Eisenbarth, George

2011-11-01

We examined changes in GAD65 and ICA-512 autoantibodies (GADA and IA-2A) during progression to type 1 diabetes (T1D). Diabetes Prevention Trial-Type 1 (DPT-1) participants were assessed for changes in positivity and titers of GADA and IA-2A during the progression to T1D. Among 99 progressors to T1D with GADA and IA-2A measurements at baseline and diagnosis (mean interval = 3.3 ± 1.5 years), GADA positivity changed little and GADA titers decreased (P < 0.01). In contrast, both IA-2A positivity and titers increased substantially (P < 0.001). Even among those positive at baseline, IA-2A titers increased from baseline to diagnosis (n = 57; P < 0.001), whereas GADA titers decreased (n = 80; P < 0.01). The same patterns of change were also evident among those positive for both autoantibodies (n = 48) at baseline. IA-2A titers increase during the years before the diagnosis of T1D, even among those positive for IA-2A. In contrast, GADA titers tend to decline during those years.

The cosmic gamma-ray background from Type Ia supernovae

NASA Technical Reports Server (NTRS)

The, Lih-Sin; Leising, Mark D.; Clayton, Donald D.

1993-01-01

We present an improved calculation of the cumulative gamma-ray spectrum of Type Ia supernovae during the history of the universe. We follow Clayton & Ward (1975) in using a few Friedmann models and two simple histories of the average galaxian nucleosynthesis rate, but we improve their calculation by modeling the gamma-ray scattering in detailed numerical models of SN Ia's. The results confirm that near 1 MeV the SN Ia background may dominate, and that it is potentially observable, with high scientific importance. A very accurate measurement of the cosmic background spectrum between 0.1 and 1.0 MeV may reveal the turn-on time and the evolution of the rate of Type Ia supernova nucleosynthesis in the universe.

Type Ia supernovae as standard candles

NASA Technical Reports Server (NTRS)

Branch, David; Miller, Douglas L.

1993-01-01

The distribution of absolute blue magnitudes among Type Ia supernovae (SNs Ia) is studied. Supernovae were used with well determined apparent magnitudes at maximum light and parent galaxies with relative distances determined by the Tully-Fisher or Dn - sigma techniques. The mean absolute blue magnitude is given and the observational dispersion is only sigma(MB) 0.36, comparable to the expected combined errors in distance, apparent magnitude, and extinction. The mean (B-V) color at maximum light is 0.03 +/- 0.04, with a dispersion sigma(B-V) = 0.20. The Cepheid-based distance to IC 4182, the parent galaxy of the normal and unextinguished Type Ia SN 1937C, leads to a Hubble constant of H(0) + 51 +/- 12 km/s Mpc. The existence of a few SNs Ia that appear to have been reddened and dimmed by dust in their parent galaxies does not seriously compromise the use of SNs Ia as distance indicators.

Type Ia supernova rate studies from the SDSS-II Supernova Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dilday, Benjamin

2008-08-01

The author presents new measurements of the type Ia SN rate from the SDSS-II Supernova Survey. The SDSS-II Supernova Survey was carried out during the Fall months (Sept.-Nov.) of 2005-2007 and discovered ~ 500 spectroscopically confirmed SNe Ia with densely sampled (once every ~ 4 days), multi-color light curves. Additionally, the SDSS-II Supernova Survey has discovered several hundred SNe Ia candidates with well-measured light curves, but without spectroscopic confirmation of type. This total, achieved in 9 months of observing, represents ~ 15-20% of the total SNe Ia discovered worldwide since 1885. The author describes some technical details of the SNmore » Survey observations and SN search algorithms that contributed to the extremely high-yield of discovered SNe and that are important as context for the SDSS-II Supernova Survey SN Ia rate measurements.« less

Life cycle thinking in impact assessment—Current practice and LCA gains

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bidstrup, Morten, E-mail: Bidstrup@plan.aau.dk

It has been advocated that life cycle thinking (LCT) should be applied in impact assessment (IA) to a greater extent, since some development proposals pose a risk of significant impacts throughout the interconnected activities of product systems. Multiple authors have proposed the usage of life cycle assessment (LCA) for such analytical advancement, but little to no research on this tool application has been founded in IA practice so far. The aim of this article is to elaborate further on the gains assigned to application of LCA. The research builds on a review of 85 Danish IA reports, which were analysedmore » for analytical appropriateness and application of LCT. Through a focus on the non-technical summary, the conclusion and the use of specific search words, passages containing LCT were searched for in each IA report. These passages were then analysed with a generic framework. The results reveal that LCT is appropriate for most of the IAs, but that LCA is rarely applied to provide such a perspective. Without LCA, the IAs show mixed performance in regard to LCT. Most IAs do consider the product provision of development proposals, but they rarely relate impacts to this function explicitly. Many IAs do consider downstream impacts, but assessments of upstream, distant impacts are generally absent. It is concluded that multiple analytical gains can be attributed to greater application of LCA in IA practice, though some level of LCT already exists. - Highlights: • Life cycle thinking is appropriate across the types and topics of impact assessment. • Yet, life cycle assessment is rarely used for adding such perspective. • Impact assessment practice does apply some degree of life cycle thinking. • However, application of life cycle assessment could bring analytical gains.« less

Immunohistochemical analysis of IA-2 family of protein tyrosine phosphatases in rat gastrointestinal endocrine cells.

PubMed

Gomi, Hiroshi; Kubota-Murata, Chisato; Yasui, Tadashi; Tsukise, Azuma; Torii, Seiji

2013-02-01

Islet-associated protein-2 (IA-2) and IA-2β (also known as phogrin) are unique neuroendocrine-specific protein tyrosine phosphatases (PTPs). The IA-2 family of PTPs was originally identified from insulinoma cells and discovered to be major autoantigens in type 1 diabetes. Despite its expression in the neural and canonical endocrine tissues, data on expression of the IA-2 family of PTPs in gastrointestinal endocrine cells (GECs) are limited. Therefore, we immunohistochemically investigated the expression of the IA-2 family of PTPs in the rat gastrointestinal tract. In the stomach, IA-2 and IA-2β were expressed in GECs that secrete serotonin, somatostatin, and cholecystokinin/gastrin-1. In addition to these hormones, secretin, gastric inhibitory polypeptide (also known as the glucose-dependent insulinotropic peptide), glucagon-like peptide-1, and glucagon, but not ghrelin were coexpressed with IA-2 or IA-2β in duodenal GECs. Pancreatic islet cells that secrete gut hormones expressed the IA-2 family of PTPs. The expression patterns of IA-2 and IA-2β were comparable. These results reveal that the IA-2 family of PTPs is expressed in a cell type-specific manner in rat GECs. The extensive expression of the IA-2 family of PTPs in pancreo-gastrointestinal endocrine cells and in the enteric plexus suggests their systemic contribution to nutritional control through a neuroendocrine signaling network.

Treatment with insulin analogs and prevalence of cardiovascular complications in patients with type 1 diabetes.

PubMed

Hasslacher, Christoph; Lorenzo Bermejo, Justo

2017-11-01

A lower incidence of cardiovascular events has been reported in type 2 diabetes patients treated with insulin analogs (IAs). Corresponding data on people affected by type 1 diabetes are not available yet. We investigated demographic and clinical data from 509 type 1 diabetics, who were treated in an outpatient clinic from 2006 to 2012. Multiple logistic regression was used to investigate the relationship between the type of insulin treatment and the prevalence of cardiovascular (CV) complications, that is, presence of coronary heart, cerebrovascular and peripheral arterial diseases, adjusting for potential confounders. Results from multiple logistic regression revealed that patients with impaired renal function [estimated glomerular filtration rate (eGFR) < 90 ml/min] show lower CV complication rates when treated with IAs (25%) compared with patients treated with human insulin (HI; 28%) and HI/IA (38%, p = 0.06). CV complication rates in the complete patient collective amounted to 17% (IA), 21% (HI) and 21% (HI/IA, p = 0.08). Examination of CV complications according to the type of IA revealed the lowest complication rates in type 1 diabetics treated with insulin lispro (5.9%) and glargine (16%). However, complication rate differences among insulin treatments did not reach statistical significance. The present cross-sectional study shows a borderline significantly lower CV morbidity in people with type 1 diabetes and impaired renal function when treated with IA compared with HI treatment after adjustment for multiple potential confounders [odds ratio (OR) = 0.78, which translates into a 22% lower complication rate]. Validation of these preliminary findings in confirmatory, prospective studies may have important clinical implications.

Outcomes of persistent intraoperative type Ia endoleak after standard endovascular aneurysm repair.

PubMed

Millen, Alistair M; Osman, Khabab; Antoniou, George A; McWilliams, Richard G; Brennan, John A; Fisher, Robert K

2015-05-01

This study analyzed outcomes for patients with persistent intraoperative type Ia endoleaks after standard endovascular aneurysm repair (EVAR). The study group was identified from a consecutive cohort of 209 patients undergoing EVAR in a tertiary center in the United Kingdom during a 2-year period. Data prospectively collected on departmental computerized databases were retrospectively analyzed. Primary outcome parameters were defined as freedom from type Ia endoleak, EVAR-related reintervention, aneurysm rupture, and aneurysm-related mortality. A completion angiogram identified 44 patients (21%) as having a type Ia endoleak, and 33 (75%) had a persistent endoleak after intraoperative adjunctive procedures, including repeated balloon moulding, aortic cuff extension, and Palmaz stent (Cordis, Miami Lakes, Fla) deployment. In the 11 patients (25%) whose endoleak was successfully abolished intraoperatively, there was no recurrence of type Ia endoleak or secondary intervention to treat type 1a endoleak during a median follow-up period of 27 months. Of the 33 patients with persistent endoleak, 31 (94%) demonstrated resolution of the endoleak on first surveillance computed tomography angiography. One patient was lost to follow-up. Embolization of the endoleak in another patient was successful using Onyx (Micro Therapeutics, Inc, Irvine, Calif) 8 days after the initial procedure. No type Ia endoleak was identified after this on any surveillance imaging, and the patient was alive 28 months later with a stable aneurysm size. In the rest of the patients, no recurrence of the endoleak in any subsequent imaging was noticed, and no secondary intervention was required during follow-up. No aneurysm-related deaths occurred, and 91% of the patients had a stable or shrinking aneurysm. Despite adjunctive intraoperative maneuvers, persistent type Ia endoleaks can be relatively common. Our study indicates that they may be observed in selected patients. Further research is required to investigate the natural course and management of type Ia endoleaks identified intraoperatively. Copyright © 2015 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Symptoms of attention-deficit/hyperactivity disorder (ADHD) moderate suicidal behaviors in college students with depressed mood.

PubMed

Patros, Connor H G; Hudec, Kristen L; Alderson, R Matt; Kasper, Lisa J; Davidson, Collin; Wingate, LaRicka R

2013-09-01

College students with attention-deficit/hyperactivity disorder-related hyperactive/impulsive (HI) and/or inattentive (IA) symptoms may be at greater risk for suicidal behavior due to core and secondary symptoms that increase their potential to engage in behaviors that put them at risk for suicidal behavior. Consequently, the current study examined the moderating effect of combined HI/IA symptoms, in addition to independent HI and IA symptoms on the relationship between depressed mood and suicidal thoughts and behavior. A sample of 1,056 undergraduate students (61.5% female, 96.4% aged 18-24 years) provided self-report ratings of mood, suicidal behavior (thoughts, self-harm, attempts, and need for medical attention), and current HI/IA symptoms. Significant moderation effects were detected, such that greater HI/IA symptoms were associated with a stronger relationship between depressed mood and suicidal ideation and attempts, but not self-harm. Current HI and IA symptoms significantly moderated the relationship between depressed mood and suicidal thoughts and suicide attempts, but did not moderate the relationship between depressed mood and self-harm and need for medical attention. The current findings suggest that the presence of combined HI/IA symptoms conveys increased suicide risk for depressed college students. Additionally, results suggest a complex relationship between independent HI and IA symptoms and severe suicidal outcomes. © 2013 Wiley Periodicals, Inc.

Type IA Supernovae

NASA Technical Reports Server (NTRS)

Wheeler, J. Craig

1992-01-01

Spectral calculations show that a model based on the thermonuclear explosion of a degenerate carbon/oxygen white dwarf provides excellent agreement with observations of Type Ia supernovae. Identification of suitable evolutionary progenitors remains a severe problem. General problems with estimation of supernova rates are outlined and the origin of Type Ia supernovae from double degenerate systems are discussed in the context of new rates of explosion per H band luminosity, the lack of observed candidates, and the likely presence of H in the vicinity of some SN Ia events. Re-examination of the problems of triggering Type Ia by accretion of hydrogen from a companion shows that there may be an avenue involving cataclysmic variables, especially if extreme hibernation occurs. Novae may channel accreting white dwarfs to a unique locus in accretion rate/mass space. Systems that undergo secular evolution to higher mass transfer rates could lead to just the conditions necessary for a Type Ia explosion. Tests involving fluorescence or absorption in a surrounding circumstellar medium and the detection of hydrogen stripped from a companion, which should appear at low velocity inside the white dwarf ejecta, are suggested. Possible observational confirmation of the former is described.

EndoAnchors to Resolve Persistent Type Ia Endoleak Secondary to Proximal Cuff With Parallel Graft Placement.

PubMed

Donselaar, Esmé J; van der Vijver-Coppen, Rozemarijn J; van den Ham, Leo H; Lardenoye, Jan Willem H P; Reijnen, Michel M P J

2016-02-01

To describe 2 patients with a distally migrated endograft causing a type Ia endoleak and treatment with a proximal cuff and chimney grafts that required EndoAnchors to finally seal the leak. Two men, ages 86 and 72 years, presented with stent-graft migration and type Ia endoleak at 5 and 15 years after endovascular repair, respectively. Both were treated with a proximal cuff in combination with a chimney graft to the left renal artery. In both cases, the type Ia endoleak persisted, likely due to gutter formation. Both patients were treated in the same setting with EndoAnchors that instantly resolved the endoleak. At 1-year follow-up, there was no recurrent endoleak or migration, with patent chimney grafts and renal arteries and stable renal function. EndoAnchors may effectively resolve a persistent type Ia endoleak arising from gutter formation after placement of a proximal cuff and chimney grafts. © The Author(s) 2015.

IA-2 autoantibody affinity in children at risk for type 1 diabetes.

PubMed

Krause, Stephanie; Chmiel, Ruth; Bonifacio, Ezio; Scholz, Marlon; Powell, Michael; Furmaniak, Jadwiga; Rees Smith, Bernard; Ziegler, Anette-G; Achenbach, Peter

2012-12-01

Autoantibodies to insulinoma-associated protein 2 (IA-2A) are associated with increased risk for type 1 diabetes. Here we examined IA-2A affinity and epitope specificity to assess heterogeneity in response intensity in relation to pathogenesis and diabetes risk in 50 children who were prospectively followed from birth. At first IA-2A appearance, affinity ranged from 10(7) to 10(11)L/mol and was high (>1.0×10(9)L/mol) in 41 (82%) children. IA-2A affinity was not associated with epitope specificity or HLA class II haplotype. On follow-up, affinity increased or remained high, and IA-2A were commonly against epitopes within the protein tyrosine phosphatase-like IA-2 domain and the homologue protein IA-2β. IA-2A were preceded or accompanied by other islet autoantibodies in 49 (98%) children, of which 34 progressed to diabetes. IA-2A affinity did not stratify diabetes risk. In conclusion, the IA-2A response in children is intense with rapid maturation against immunogenic epitopes and a strong association with diabetes development. Copyright © 2012 Elsevier Inc. All rights reserved.

Rising Incidence of Type 1 Diabetes Is Associated With Altered Immunophenotype at Diagnosis

PubMed Central

Long, Anna E.; Gillespie, Kathleen M.; Rokni, Saba; Bingley, Polly J.; Williams, Alistair J.K.

2012-01-01

The incidence of type 1 diabetes has increased rapidly over recent decades, particularly in young children. We aimed to determine whether this rise was associated with changes in patterns of humoral islet autoimmunity at diagnosis. Autoantibodies to insulin (IAA), GAD (GADA), islet antigen-2 (IA-2A), and zinc transporter 8 (ZnT8A) were measured by radioimmunoassay in sera collected from children and young adults with newly diagnosed type 1 diabetes between 1985 and 2002. The influence of date of diagnosis on prevalence and level of autoantibodies was investigated by logistic regression with adjustment for age and HLA class II genetic risk. Prevalence of IA-2A and ZnT8A increased significantly over the period studied, and this was mirrored by raised levels of IA-2A, ZnT8A, and IA-2β autoantibodies (IA-2βA). IAA and GADA prevalence and levels did not change. Increases in IA-2A, ZnT8A, and IA-2βA at diagnosis during a period of rising incidence suggest that the process leading to type 1 diabetes is now characterized by a more intense humoral autoimmune response. Understanding how changes in environment or lifestyle alter the humoral autoimmune response to islet antigens should help explain why the incidence of type 1 diabetes is increasing and may suggest new strategies for preventing disease. PMID:22315309

COX-1 vs. COX-2 as a determinant of basal tone in the internal anal sphincter

PubMed Central

de Godoy, Márcio A. F.; Rattan, Neeru; Rattan, Satish

2009-01-01

Prostanoids, produced endogenously via cyclooxygenases (COXs), have been implicated in the sustained contraction of different smooth muscles. The two major types of COXs are COX-1 and COX-2. The COX subtype involved in the basal state of the internal anal sphincter (IAS) smooth muscle tone is not known. To identify the COX subtype, we examined the effect of COX-1- and COX-2-selective inhibitors, SC-560 and rofecoxib, respectively, on basal tone in the rat IAS. We also determined the effect of selective deletion of COX-1 and COX-2 genes (COX-1−/− and COX-2−/− mice) on basal tone in murine IAS. Our data show that SC-560 causes significantly more efficacious and potent concentration-dependent decreases in IAS tone than rofecoxib. In support of these data, significantly higher levels of COX-1 than COX-2 mRNA were found in the IAS. In addition, higher levels of COX-1 mRNA and protein were expressed in rat IAS than rectal smooth muscle. In wild-type mice, IAS tone was decreased 41.4 ± 3.4% (mean ± SE) by SC-560 (1 × 10−5 M) and 5.4 ± 2.2% by rofecoxib (P < 0.05, n = 5). Basal tone was 0.172 ± 0.021 mN//mg in the IAS from wild-type mice and significantly less (0.080 ± 0.015 mN/mg) in the IAS from COX-1−/− mice (P < 0.05, n = 5). However, basal tone in COX-2−/− mice was not significantly different from that in wild-type mice. We conclude that COX-1-related products contribute significantly to IAS tone. PMID:19056763

COX-1 vs. COX-2 as a determinant of basal tone in the internal anal sphincter.

PubMed

de Godoy, Márcio A F; Rattan, Neeru; Rattan, Satish

2009-02-01

Prostanoids, produced endogenously via cyclooxygenases (COXs), have been implicated in the sustained contraction of different smooth muscles. The two major types of COXs are COX-1 and COX-2. The COX subtype involved in the basal state of the internal anal sphincter (IAS) smooth muscle tone is not known. To identify the COX subtype, we examined the effect of COX-1- and COX-2-selective inhibitors, SC-560 and rofecoxib, respectively, on basal tone in the rat IAS. We also determined the effect of selective deletion of COX-1 and COX-2 genes (COX-1(-/-) and COX-2(-/-) mice) on basal tone in murine IAS. Our data show that SC-560 causes significantly more efficacious and potent concentration-dependent decreases in IAS tone than rofecoxib. In support of these data, significantly higher levels of COX-1 than COX-2 mRNA were found in the IAS. In addition, higher levels of COX-1 mRNA and protein were expressed in rat IAS than rectal smooth muscle. In wild-type mice, IAS tone was decreased 41.4 +/- 3.4% (mean +/- SE) by SC-560 (1 x 10(-5) M) and 5.4 +/- 2.2% by rofecoxib (P < 0.05, n = 5). Basal tone was 0.172 +/- 0.021 mN//mg in the IAS from wild-type mice and significantly less (0.080 +/- 0.015 mN/mg) in the IAS from COX-1(-/-) mice (P < 0.05, n = 5). However, basal tone in COX-2(-/-) mice was not significantly different from that in wild-type mice. We conclude that COX-1-related products contribute significantly to IAS tone.

Reduction in voltage-gated K+ channel activity in primary sensory neurons in painful diabetic neuropathy: role of brain-derived neurotrophic factor.

PubMed

Cao, Xue-Hong; Byun, Hee-Sun; Chen, Shao-Rui; Cai, You-Qing; Pan, Hui-Lin

2010-09-01

Abnormal hyperexcitability of primary sensory neurons plays an important role in neuropathic pain. Voltage-gated potassium (Kv) channels regulate neuronal excitability by affecting the resting membrane potential and influencing the repolarization and frequency of the action potential. In this study, we determined changes in Kv channels in dorsal root ganglion (DRG) neurons in a rat model of diabetic neuropathic pain. The densities of total Kv, A-type (IA) and sustained delayed (IK) currents were markedly reduced in medium- and large-, but not in small-, diameter DRG neurons in diabetic rats. Quantitative RT-PCR analysis revealed that the mRNA levels of IA subunits, including Kv1.4, Kv3.4, Kv4.2, and Kv4.3, in the DRG were reduced approximately 50% in diabetic rats compared with those in control rats. However, there were no significant differences in the mRNA levels of IK subunits (Kv1.1, Kv1.2, Kv2.1, and Kv2.2) in the DRG between the two groups. Incubation with brain-derived neurotrophic factor (BDNF) caused a large reduction in Kv currents, especially IA currents, in medium and large DRG neurons from control rats. Furthermore, the reductions in Kv currents and mRNA levels of IA subunits in diabetic rats were normalized by pre-treatment with anti-BDNF antibody or K252a, a TrkB tyrosine kinase inhibitor. In addition, the number of medium and large DRG neurons with BDNF immunoreactivity was greater in diabetic than control rats. Collectively, our findings suggest that diabetes primarily reduces Kv channel activity in medium and large DRG neurons. Increased BDNF activity in these neurons likely contributes to the reduction in Kv channel function through TrkB receptor stimulation in painful diabetic neuropathy.

Management of Immediate Post-Endovascular Aortic Aneurysm Repair Type Ia Endoleaks and Late Outcomes.

PubMed

AbuRahma, Ali F; Hass, Stephen M; AbuRahma, Zachary T; Yacoub, Michael; Mousa, Albeir Y; Abu-Halimah, Shadi; Dean, L Scott; Stone, Patrick A

2017-04-01

Post-endovascular aortic aneurysm repair (EVAR) endoleaks and the need for reintervention are challenging. Additional endovascular treatment is advised for type Ia endoleaks detected on post-EVAR completion angiogram. This study analyzed management and late outcomes of these endoleaks. This was a retrospective review of prospectively collected data from EVAR patients during a 10-year period. All post-EVAR type Ia endoleaks on completion angiogram were identified (group A) and their early (30-day) and late outcomes were compared with outcomes of patients without endoleaks (group B). Kaplan-Meier analysis was used for survival analysis, sac expansion, late type Ia endoleak, and reintervention. Seventy-one of 565 (12.6%) patients had immediate post-EVAR type Ia endoleak. Early intervention (proximal aortic cuffs and/or stenting) was used in 56 of 71 (79%) in group A vs 31 of 494 (6%) in group B (p < 0.0001). Late type Ia endoleak was noted in 9 patients (13%) in group A at a mean follow-up of 28 months vs 10 patients (2%) in group B at a mean follow-up of 32 months (p < 0.0001). Late sac expansion and reintervention rates were 9% and 10% for group A vs 5% and 3% for group B (p = 0.2698 and p = 0.0198), respectively. Freedom rates from late type Ia endoleaks at 1, 3, and 5 years for group A were 88%, 85%, and 80% vs 98%, 98%, and 96% for group B (p < 0.001); and for late intervention, were 94%, 92%, and 77% for group A, and 99%, 97%, and 95% for group B (p = 0.007), respectively. Survival rates were similar. Immediate post-EVAR type Ia endoleaks are associated with higher rates of early interventions, late endoleaks and reintervention, which will necessitate strict post-EVAR surveillance. Copyright © 2016 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

Management of Immediate Post-Endovascular Aortic Aneurysm Repair Type Ia Endoleaks and Late Outcomes

PubMed Central

AbuRahma, Ali F; Hass, Stephen M; AbuRahma, Zachary T; Yacoub, Michael; Mousa, Albeir Y; Abu-Halimah, Shadi; Dean, L Scott; Stone, Patrick A

2017-01-01

BACKGROUND Post-endovascular aortic aneurysm repair (EVAR) endoleaks and the need for reintervention are challenging. Additional endovascular treatment is advised for type Ia endoleaks detected on post-EVAR completion angiogram. This study analyzed management and late outcomes of these endoleaks. STUDY DESIGN This was a retrospective review of prospectively collected data from EVAR patients during a 10-year period. All post-EVAR type Ia endoleaks on completion angiogram were identified (group A) and their early (30-day) and late outcomes were compared with outcomes of patients without endoleaks (group B). Kaplan-Meier analysis was used for survival analysis, sac expansion, late type Ia endoleak, and reintervention. RESULTS Seventy-one of 565 (12.6%) patients had immediate post-EVAR type Ia endoleak. Early intervention (proximal aortic cuffs and/or stenting) was used in 56 of 71 (79%) in group A vs 31 of 494 (6%) in group B (p < 0.0001). Late type Ia endoleak was noted in 9 patients (13%) in group A at a mean follow-up of 28 months vs 10 patients (2%) in group B at a mean follow-up of 32 months (p < 0.0001). Late sac expansion and reintervention rates were 9% and 10% for group A vs 5% and 3% for group B (p = 0.2698 and p = 0.0198), respectively. Freedom rates from late type Ia endoleaks at 1, 3, and 5 years for group A were 88%, 85%, and 80% vs 98%, 98%, and 96% for group B (p < 0.001); and for late intervention, were 94%, 92%, and 77% for group A, and 99%, 97%, and 95% for group B (p = 0.007), respectively. Survival rates were similar. CONCLUSIONS Immediate post-EVAR type Ia endoleaks are associated with higher rates of early interventions, late endoleaks and reintervention, which will necessitate strict post-EVAR surveillance. PMID:28017805

On-line immunoaffinity solid-phase extraction capillary electrophoresis mass spectrometry using Fab´antibody fragments for the analysis of serum transthyretin.

PubMed

Pont, Laura; Benavente, Fernando; Barbosa, José; Sanz-Nebot, Victoria

2017-08-01

This paper describes an on-line immunoaffinity solid-phase extraction capillary electrophoresis mass spectrometry (IA-SPE-CE-MS) method using an immunoaffinity sorbent with Fab' antibody fragments (Fab'-IA) for the analysis of serum transthyretin (TTR), a homotetrameric protein (M r ~56,000) involved in different types of amyloidosis. The IA sorbent was prepared by covalent attachment of Fab' fragments obtained from a polyclonal IgG antibody against TTR to succinimidyl silica particles. The Fab'-IA-SPE-CE-MS methodology was first established analyzing TTR standard solutions. Under optimized conditions, repeatability and reproducibility were acceptable, the method was linear between 1 and 25µgmL -1 , limits of detection (LODs) were around 0.5µgmL -1 (50-fold lower than by CE-MS, ~25µgmL -1 ) and different TTR conformations were observed (folded and unfolded). The applicability of the developed method to screen for familial amyloidotic polyneuropathy type I (FAP-I), which is the most common hereditary systemic amyloidosis, was evaluated analyzing serum samples from healthy controls and FAP-I patients. For the analysis of sera, the most abundant proteins were precipitated with 5% (v/v) of phenol before Fab'-IA-SPE-CE-MS. The current method enhanced our previous results for the analysis of TTR using intact antibodies immobilized on magnetic beads. It allowed a slight improvement on LODs (2-fold), the detection of proteoforms found at lower concentrations and the preparation of microcartridges with extended durability. Copyright © 2017. Published by Elsevier B.V.

Type Ia Supernova Light Curve Inference: Hierarchical Models for Nearby SN Ia in the Optical and Near Infrared

NASA Astrophysics Data System (ADS)

Mandel, Kaisey; Kirshner, R. P.; Narayan, G.; Wood-Vasey, W. M.; Friedman, A. S.; Hicken, M.

2010-01-01

I have constructed a comprehensive statistical model for Type Ia supernova light curves spanning optical through near infrared data simultaneously. The near infrared light curves are found to be excellent standard candles (sigma(MH) = 0.11 +/- 0.03 mag) that are less vulnerable to systematic error from dust extinction, a major confounding factor for cosmological studies. A hierarchical statistical framework incorporates coherently multiple sources of randomness and uncertainty, including photometric error, intrinsic supernova light curve variations and correlations, dust extinction and reddening, peculiar velocity dispersion and distances, for probabilistic inference with Type Ia SN light curves. Inferences are drawn from the full probability density over individual supernovae and the SN Ia and dust populations, conditioned on a dataset of SN Ia light curves and redshifts. To compute probabilistic inferences with hierarchical models, I have developed BayeSN, a Markov Chain Monte Carlo algorithm based on Gibbs sampling. This code explores and samples the global probability density of parameters describing individual supernovae and the population. I have applied this hierarchical model to optical and near infrared data of over 100 nearby Type Ia SN from PAIRITEL, the CfA3 sample, and the literature. Using this statistical model, I find that SN with optical and NIR data have a smaller residual scatter in the Hubble diagram than SN with only optical data. The continued study of Type Ia SN in the near infrared will be important for improving their utility as precise and accurate cosmological distance indicators.

Outcomes and morphologic changes of immediate type Ia endoleak following endovascular repair of acute type B aortic dissection.

PubMed

Huang, Wenhui; Yang, Fan; Luo, Jianfang; Xie, NianJin; He, Pengcheng; Luo, Songyuan; Liu, Yuan; Zhou, Yingling; Fan, Ruixin; Huang, Meiping; Chen, Jiyan

2015-02-01

The clinical significance of immediate type Ia endoleaks after thoracic endovascular aortic repair (TEVAR) for aneurysms has been described in detail. However, this phenomenon is still controversial in TEVAR patients treated for acute type B aortic dissection. A single-institution study was conducted in 81 prospectively evaluated patients treated between January 2012 and June 2012 for acute type B aortic dissection. Preoperative and postoperative computed tomography angiography (CTA) images were analyzed using 3-dimensional reconstruction to measure the areas and indices of the true lumen, false lumen, and total aorta in the proximal, middle, and distal descending thoracic aorta. Data were analyzed and compared between the 2 groups of patients, with and without immediate type Ia endoleaks. The average follow-up period was 12 months (range 10-13 months) after the procedure. TEVAR was successfully performed in all patients (mean age 53 years; 86% men). Thirty-six of the 81 patients were diagnosed with complicated type B dissection, including persistent pain (19/36, 52.7%), refractory hypertension (4/36, 11.1%), and end-organ ischemia (13/36, 36.1%). Of all the patients, 37 (45.7%) were diagnosed with immediate type Ia endoleaks. The differences between the 30-day and 1-year all-cause mortality rates between the 2 groups were nonsignificant (13.5% vs. 2.2%, P = 0.08; 16.2% vs. 4.5%, P = 0.13). No stroke or paraplegia occurred during the follow-up. Reintervention was performed in 2 patients for delayed type I endoleaks in the group without immediate type Ia endoleaks. Pre- and postoperative CTA images were available for analysis in 54 patients. Among them, 24 patients had type Ia endoleaks. Patients with immediate type Ia endoleaks had a significantly larger preoperative distal false lumen area (498 ± 274 vs. 284 ± 213 mm(2), P = 0.02) and a larger distal aortic area (759 ± 275 vs. 624 ± 185 mm(2), P = 0.03). The 1-year follow-up CTA demonstrated significantly smaller true lumen indices and larger false lumen areas and false lumen indices in the proximal, middle, and distal sections in patients with immediate type Ia endoleaks. Differences in the postoperative morphological changes of the whole descending thoracic aorta were significant between the 2 groups, with the maximum area and the proximal, middle, and distal regions involved. The occurrence of endoleaks and the rates of postoperative false lumen thrombosis throughout the length of stent grafts were not significant at 1-year follow-up. The majority of immediate type Ia endoleaks following TEVAR in acute type B aortic dissections could seal spontaneously, without additional procedures needed. However, the appearance of such complications could be a risk factor of poorer aortic remodeling. Careful surveillance is recommended more frequently in patients with immediate type Ia endoleaks. Copyright © 2015 Elsevier Inc. All rights reserved.

Diversity in extinction laws of Type Ia supernovae measured between 0.2 and 2 μm

DOE PAGES

Amanullah, R.; Johansson, J.; Goobar, A.; ...

2015-09-07

Here, we present ultraviolet (UV) observations of six nearby Type Ia supernovae (SNe Ia) obtained with the Hubble Space Telescope, three of which were also observed in the near-IR (NIR) with Wide-Field Camera 3. UV observations with the Swift satellite, as well as ground-based optical and NIR data provide complementary information. The combined data set covers the wavelength range 0.2–2 μm. By also including archival data of SN 2014J, we analyse a sample spanning observed colour excesses up to E(B - V) = 1.4 mag. We study the wavelength-dependent extinction of each individual SN and find a diversity of reddeningmore » laws when characterized by the total-to-selective extinction R V. In particular, we note that for the two SNe with E(B - V) ≳1 mag, for which the colour excess is dominated by dust extinction, we find R V = 1.4 ± 0.1 and R V = 2.8 ± 0.1. Adding UV photometry reduces the uncertainty of fitted R V by ~50 percent allowing us to also measure R V of individual low-extinction objects which point to a similar diversity, currently not accounted for in the analyses when SNe Ia are used for studying the expansion history of the Universe.« less

Characteristics of Intracranial Aneurysms in the Else Kröner-Fresenius Registry of Autosomal Dominant Polycystic Kidney Disease

PubMed Central

Neumann, Hartmut P.H.; Malinoc, Angelica; Bacher, Janina; Nabulsi, Zinaida; Ivanovas, Vera; Bruechle, Nadine Ortiz; Mader, Irina; Hoffmann, Michael M.; Riegler, Peter; Kraemer-Guth, Annette; Burchardi, Christian; Schaeffner, Elke; Martin, Rodolfo S.; Azurmendi, Pablo J.; Zerres, Klaus; Jilg, Cordula; Eng, Charis; Gläsker, Sven

2012-01-01

Background Patients who harbor intracranial aneurysms (IAs) run a risk for aneurysm rupture and subsequent subarachnoid hemorrhage which frequently results in permanent deficits or death. Prophylactic treatment of unruptured aneurysms is possible and recommended depending on the size and location of the aneurysm as well as patient age and condition. IAs are major manifestations of autosomal dominant polycystic kidney disease (ADPKD). Current guidelines do not suggest surveillance of IAs in ADPKD except in the setting of family history if IA was known in any relative with ADPKD. Management of IAs in ADPKD is problematic because limited data exist from large studies. Methods We established the Else Kröner-Fresenius Registry for ADPKD in Germany. Clinical data were assessed for age at diagnosis of IAs, stage of renal insufficiency, and number, location and size of IAs as well as family history of cerebral events. Patients with symptomatic or asymptomatic IAs were included. All patients with ADPKD-related IAs were offered mutation scanning of the susceptibility genes for ADPKD, the PKD1 and PKD2 genes. Results Of 463 eligible ADPKD patients from the population base of Germany, 32 (7%) were found to have IAs, diagnosed at the age of 2–71 years, 19 females and 13 males. Twenty (63%) of these 32 patients were symptomatic, whereas IAs were detected in an asymptomatic stage in 12 patients. IAs were multifocal in 12 and unifocal in 20 patients. In 26 patients (81%), IAs were diagnosed before end-stage renal failure. Twenty-five out of 27 unrelated index cases (93%) had no IAs or cerebral events documented in their relatives with ADPKD. In 16 unrelated index patients and 3 relatives, we detected germline mutations. The mutations were randomly distributed across the PKD1 gene in 14 and the PKD2 gene in 2 index cases. Questionnaires answered for 320/441 ADPKD patients without IAs revealed that only 45/320 (14%) had MR angiography. Conclusion In ADPKD, rupture of IAs occurs frequently before the start of dialysis, is only infrequently associated with a family history of IAs or subarachnoid hemorrhage, and is associated with mutations either of the PKD1 or the PKD2 gene of any type. Screening for IAs is widely insufficiently performed, should not be restricted to families with a history of cerebral events and should be started before end-stage renal failure. PMID:23139683

Autonomous System Technologies for Resilient Airspace Operations

NASA Technical Reports Server (NTRS)

Houston, Vincent E.; Le Vie, Lisa R.

2017-01-01

Increasing autonomous systems within the aircraft cockpit begins with an effort to understand what autonomy is and developing the technology that encompasses it. Autonomy allows an agent, human or machine, to act independently within a circumscribed set of goals; delegating responsibility to the agent(s) to achieve overall system objective(s). Increasingly Autonomous Systems (IAS) are the highly sophisticated progression of current automated systems toward full autonomy. Working in concert with humans, these types of technologies are expected to improve the safety, reliability, costs, and operational efficiency of aviation. IAS implementation is imminent, which makes the development and the proper performance of such technologies, with respect to cockpit operation efficiency, the management of air traffic and data communication information, vital. A prototype IAS agent that attempts to optimize the identification and distribution of "relevant" air traffic data to be utilized by human crews during complex airspace operations has been developed.

See Change: Cosmology Analysis Update for the Supernova Cosmology Project High-z Cluster Supernova Survey

NASA Astrophysics Data System (ADS)

Hayden, Brian; Aldering, Gregory; Amanullah, Rahman; Barbary, Kyle; Bohringer, Hans; Boone, Kyle Robert; Brodwin, Mark; Cunha, Carlos; Currie, Miles; Deustua, Susana; Dixon, Samantha; Eisenhardt, Peter; Fassbender, Rene; Fruchter, Andrew; Gladders, Michael; Gonzalez, Anthony; Goobar, Ariel; Hildebrandt, Hendrik; Hilton, Matt; Hoekstra, Henk; Hook, Isobel; Huang, Xiaosheng; Huterer, Dragan; Jee, Myungkook James; Kim, Alex; Kowalski, Marek; Lidman, Chris; Linder, Eric; Luther, Kyle; Meyers, Joshua; Muzzin, Adam; Nordin, Jakob; Pain, Reynald; Perlmutter, Saul; Richard, Johan; Rosati, Piero; Rozo, Eduardo; Rubin, David; Ruiz-Lapuente, Pilar; Rykoff, Eli; Santos, Joana; Myers Saunders, Clare; Sofiatti, Caroline; Spadafora, Anthony L.; Stanford, Spencer; Stern, Daniel; Suzuki, Nao; Webb, Tracy; Wechsler, Risa; Williams, Steven; Willis, Jon; Wilson, Gillian; Yen, Mike

2018-01-01

The Supernova Cosmology Project has finished executing a large (174 orbits, cycles 22-23) Hubble Space Telescope program, which has measured ~30 type Ia Supernovae above z~1 in the highest-redshift, most massive galaxy clusters known to date. We present the status of the ongoing blinded cosmology analysis, demonstrating substantial improvement to the uncertainty on the Dark Energy density above z~1. Our extensive HST and ground-based campaign has already produced unique results; we have confirmed several of the highest redshift cluster members known to date, confirmed the redshift of one of the most massive galaxy clusters expected across the entire sky, and characterized one of the most extreme starburst environments yet known in a z~1.7 cluster. We have also discovered a lensed SN Ia at z=2.22 magnified by a factor of ~2.8, which is the highest spectroscopic redshift SN Ia currently known.

Evaluation of popliteal artery branching patterns and a new subclassification of the 'usual' branching pattern.

PubMed

Celtikci, Pinar; Ergun, Onur; Durmaz, Hasan Ali; Conkbayir, Isik; Hekimoglu, Baki

2017-09-01

To determine the frequency of popliteal artery branching variations in a wide study cohort and to investigate the relationship between these variations and infrapopliteal peripheral arterial disease (PAD). A subclassification was proposed for the most encountered type I-A, utilizing tibio-fibular trunk (TFT) length. A total number of 1184 lower extremity digital subtraction angiography (DSA) studies of 669 patients were evaluated. Following exclusion, 863 lower extremity DSA studies (431 right, 432 left) of 545 patients were enrolled. Popliteal artery branching type, patency of anterior tibial artery (ATA), fibular artery (FA) and posterior tibial artery (PTA) in each extremity and TFT length for type I-A extremities were recorded. Percentages of branching patterns, mean length and cut-off value of TFT and incidence of PAD in different types of branching were calculated. Type I-A was the most common type of branching (81.3%). Frequency of branching pattern variation was 18.7%, the most common variation category was category III (12.2%) and the most common variation type was type III-A (5.6%). ATA and PTA had higher percentages of PAD in extremities with variant branching types. Cut-off value of 3 cm for TFT length was proposed in order to subclassify type I-A. Our study cohort presents a higher incidence of popliteal artery branching variations. Some branching variations might have effect on the involvement pattern of the infrapopliteal arteries by PAD. We propose a subclassification for type I-A; type I-A-S (TFT < 3 cm) and type I-A-L (TFT ≥ 3 cm) which might have impact on interventional procedures.

Heterogeneous nucleation of nitric acid trihydrate on clay minerals: relevance to type ia polar stratospheric clouds.

PubMed

Hatch, Courtney D; Gough, Raina V; Toon, Owen B; Tolbert, Margaret A

2008-01-17

Although critical to atmospheric modeling of stratospheric ozone depletion, selective heterogeneous nuclei that promote the formation of Type Ia polar stratospheric clouds (PSCs) are largely unknown. While mineral particles are known to be good ice nuclei, it is currently not clear whether they are also good nuclei for PSCs. In the present study, a high-vacuum chamber equipped with transmission Fourier transform infrared spectroscopy and a quadrupole mass spectrometer was used to study heterogeneous nucleation of nitric acid trihydrate (NAT) on two clay minerals-Na-montmorillonite and kaolinite-as analogs of atmospheric terrestrial and extraterrestrial minerals. The minerals are first coated with a 3:1 supercooled H2O/HNO3 solution prior to the observed nucleation of crystalline NAT. At 220 K, NAT formation was observed at low SNAT values of 12 and 7 on kaolinite and montmorillonite clays, respectively. These are the lowest SNAT values reported in the literature on any substrate. However, NAT nucleation exhibited significant temperature dependence. At lower temperatures, representative of typical polar stratospheric conditions, much higher supersaturations were required before nucleation was observed. Our results suggest that NAT nucleation on mineral particles, not previously treated with sulfuric acid, may not be an important nucleation platform for Type Ia PSCs under normal polar stratospheric conditions.

Rates and delay times of Type Ia supernovae in the helium-enriched main-sequence donor scenario

NASA Astrophysics Data System (ADS)

Liu, Zheng-Wei; Stancliffe, Richard J.

2018-04-01

The nature of the progenitors of Type Ia supernovae (SNe Ia) remains a mystery. Comparing theoretical rates and delay-time distributions of SNe Ia with those inferred observationally can constrain their progenitor models. In this work, taking thermohaline mixing into account in the helium-enriched main-sequence (HEMS) donor scenario, we address rates and delay times of SNe Ia in this channel by combining the results of self-consistent binary evolution calculations with population synthesis models. We find that the Galactic SN Ia rate from the HEMS donor scenario is around 0.6-1.2 × 10-3 yr-1, which is about 30 per cent of the observed rate. Delay times of SNe Ia in this scenario cover a wide range of 0.1-1.0 Gyr. We also present the pre-explosion properties of companion stars in the HEMS donor scenario, which will be helpful for placing constraints on SN Ia progenitors through analysing their pre-explosion images.

Photometric properties of intermediate-redshift Type Ia supernovae observed by the Sloan Digital Sky Survey-II Supernova Survey

DOE PAGES

Takanashi, N.; Doi, M.; Yasuda, N.; ...

2016-12-06

We have analyzed multi-band light curves of 328 intermediate redshift (0.05 <= z < 0.24) type Ia supernovae (SNe Ia) observed by the Sloan Digital Sky Survey-II Supernova Survey (SDSS-II SN Survey). The multi-band light curves were parameterized by using the Multi-band Stretch Method, which can simply parameterize light curve shapes and peak brightness without dust extinction models. We found that most of the SNe Ia which appeared in red host galaxies (u - r > 2.5) don't have a broad light curve width and the SNe Ia which appeared in blue host galaxies (u - r < 2.0) havemore » a variety of light curve widths. The Kolmogorov-Smirnov test shows that the colour distribution of SNe Ia appeared in red / blue host galaxies is different (significance level of 99.9%). We also investigate the extinction law of host galaxy dust. As a result, we find the value of Rv derived from SNe Ia with medium light curve width is consistent with the standard Galactic value. On the other hand, the value of Rv derived from SNe Ia that appeared in red host galaxies becomes significantly smaller. Furthermore, these results indicate that there may be two types of SNe Ia with different intrinsic colours, and they are obscured by host galaxy dust with two different properties.« less

Photometric properties of intermediate-redshift Type Ia supernovae observed by the Sloan Digital Sky Survey-II Supernova Survey

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takanashi, N.; Doi, M.; Yasuda, N.

We have analyzed multi-band light curves of 328 intermediate redshift (0.05 <= z < 0.24) type Ia supernovae (SNe Ia) observed by the Sloan Digital Sky Survey-II Supernova Survey (SDSS-II SN Survey). The multi-band light curves were parameterized by using the Multi-band Stretch Method, which can simply parameterize light curve shapes and peak brightness without dust extinction models. We found that most of the SNe Ia which appeared in red host galaxies (u - r > 2.5) don't have a broad light curve width and the SNe Ia which appeared in blue host galaxies (u - r < 2.0) havemore » a variety of light curve widths. The Kolmogorov-Smirnov test shows that the colour distribution of SNe Ia appeared in red / blue host galaxies is different (significance level of 99.9%). We also investigate the extinction law of host galaxy dust. As a result, we find the value of Rv derived from SNe Ia with medium light curve width is consistent with the standard Galactic value. On the other hand, the value of Rv derived from SNe Ia that appeared in red host galaxies becomes significantly smaller. Furthermore, these results indicate that there may be two types of SNe Ia with different intrinsic colours, and they are obscured by host galaxy dust with two different properties.« less

Supernova Cosmology Project

Science.gov Websites

Supernova Survey: An Intensive HST Survey for z>1 Type Ia Supernovae by Targeting Galaxy Clusters Survey new survey strategy to discover and study high redshift Type Ia supernovae (SNe Ia) using the Hubble improvement in the efficiency of finding SNe compared to an HST field survey and a factor of three improvement

ChIA-PET2: a versatile and flexible pipeline for ChIA-PET data analysis

PubMed Central

Li, Guipeng; Chen, Yang; Snyder, Michael P.; Zhang, Michael Q.

2017-01-01

ChIA-PET2 is a versatile and flexible pipeline for analyzing different types of ChIA-PET data from raw sequencing reads to chromatin loops. ChIA-PET2 integrates all steps required for ChIA-PET data analysis, including linker trimming, read alignment, duplicate removal, peak calling and chromatin loop calling. It supports different kinds of ChIA-PET data generated from different ChIA-PET protocols and also provides quality controls for different steps of ChIA-PET analysis. In addition, ChIA-PET2 can use phased genotype data to call allele-specific chromatin interactions. We applied ChIA-PET2 to different ChIA-PET datasets, demonstrating its significantly improved performance as well as its ability to easily process ChIA-PET raw data. ChIA-PET2 is available at https://github.com/GuipengLi/ChIA-PET2. PMID:27625391

Type Ia Supernova Intrinsic Magnitude Dispersion and the Fitting of Cosmological Parameters

NASA Astrophysics Data System (ADS)

Kim, A. G.

2011-02-01

I present an analysis for fitting cosmological parameters from a Hubble diagram of a standard candle with unknown intrinsic magnitude dispersion. The dispersion is determined from the data, simultaneously with the cosmological parameters. This contrasts with the strategies used to date. The advantages of the presented analysis are that it is done in a single fit (it is not iterative), it provides a statistically founded and unbiased estimate of the intrinsic dispersion, and its cosmological-parameter uncertainties account for the intrinsic-dispersion uncertainty. Applied to Type Ia supernovae, my strategy provides a statistical measure to test for subtypes and assess the significance of any magnitude corrections applied to the calibrated candle. Parameter bias and differences between likelihood distributions produced by the presented and currently used fitters are negligibly small for existing and projected supernova data sets.

Spontaneous delayed sealing in selected patients with a primary type-Ia endoleak after endovascular aneurysm repair.

PubMed

Bastos Gonçalves, F; Verhagen, H J M; Vasanthananthan, K; Zandvoort, H J A; Moll, F L; van Herwaarden, J A

2014-07-01

Direct additional therapy is advised for type-Ia endoleaks detected on completion angiography after endovascular aneurysm repair (EVAR). Additional intraoperative endovascular procedures are, however, often challenging or not possible, and direct open conversion is unattractive. The results of a selective, conservative strategy for patients with primary type-Ia endoleak has been analysed. This was a retrospective, single-centre study (UMC, Utrecht, NL). From 2004 to 2008, all patients with a primary type-Ia endoleak and suitable anatomy for EVAR, stentgraft oversizing ≥15%, and optimal deployment were included. Complications during follow-up were studied and all sequential CTA scans were reviewed. These were compared with the remaining patients, treated during the same period. Fifteen patients were included (14 male, median age 77, range 67-85) with a median aneurysm diameter of 60 mm (48-80), an aneurysm neck diameter of 26 mm (21-32), a neck length of 29 mm (11-39), and infrarenal angulation of 49° (31-90). One patient suffered rupture 2 days after EVAR - leading to the only AAA-related death. Eight of the 15 type-Ia endoleaks disappeared spontaneously on the first postoperative CTA, obtained within 1 week of EVAR. On the second postoperative CTA, obtained a median of 5 months (1-12) after EVAR, all remaining endoleaks had sealed. One recurrence occurred at 4.85 years. During a median follow-up of 3.3 years, there were five secondary interventions. Compared with controls, there were more secondary (or recurrent) type-1a endoleaks (13% vs. 4%), endograft migrations (13% vs. 3%), sac growths (33% vs. 16%), and secondary interventions (33% vs. 23%). None of these differences however, were statistically significant. All but one of the primary type-Ia endoleaks sealed spontaneously. Until sealing, the risk of rupture persisted, but subsequently only one recurrence of type-Ia endoleak was seen. In selected patients, a conservative approach for primary type-Ia endoleaks may be justified. Copyright © 2014 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Sugar intake is associated with progression from islet autoimmunity to type 1 diabetes: the Diabetes Autoimmunity Study in the Young

PubMed Central

Lamb, Molly M.; Frederiksen, Brittni; Seifert, Jennifer A.; Kroehl, Miranda; Rewers, Marian; Norris, Jill M.

2015-01-01

Aims/hypothesis Dietary sugar intake may increase insulin production, stress the beta cells and increase the risk for islet autoimmunity (IA) and subsequent type 1 diabetes. Methods Since 1993, the Diabetes Autoimmunity Study in the Young (DAISY) has followed children at increased genetic risk for type 1 diabetes for the development of IA (autoantibodies to insulin, GAD or protein tyrosine phosphatase-like protein [IA2] twice or more in succession) and progression to type 1 diabetes. Information on intake of fructose, sucrose, total sugars, sugar-sweetened beverages, beverages with non-nutritive sweetener and juice was collected prospectively throughout childhood via food frequency questionnaires (FFQs). We examined diet records for 1,893 children (mean age at last follow-up 10.2 years); 142 developed IA and 42 progressed to type 1 diabetes. HLA genotype was dichotomised as high risk (HLA-DR3/4,DQB1*0302) or not. All Cox regression models were adjusted for total energy, FFQ type, type 1 diabetes family history, HLA genotype and ethnicity. Results In children with IA, progression to type 1 diabetes was significantly associated with intake of total sugars (HR 1.75, 95% CI 1.07–2.85). Progression to type 1 diabetes was also associated with increased intake of sugar-sweetened beverages in those with the high-risk HLA genotype (HR 1.84, 95% CI 1.25–2.71), but not in children without it (interaction p value = 0.02). No sugar variables were associated with IA risk. Conclusions/interpretation Sugar intake may exacerbate the later stage of type 1 diabetes development; sugar-sweetened beverages may be especially detrimental to children with the highest genetic risk of developing type 1 diabetes. PMID:26048237

An asymptotic-giant-branch star in the progenitor system of a type Ia supernova.

PubMed

Hamuy, Mario; Phillips, M M; Suntzeff, Nicholas B; Maza, José; González, L E; Roth, Miguel; Krisciunas, Kevin; Morrell, Nidia; Green, E M; Persson, S E; McCarthy, P J

2003-08-07

Stars that explode as supernovae come in two main classes. A type Ia supernova is recognized by the absence of hydrogen and the presence of elements such as silicon and sulphur in its spectrum; this class of supernova is thought to produce the majority of iron-peak elements in the Universe. They are also used as precise 'standard candles' to measure the distances to galaxies. While there is general agreement that a type Ia supernova is produced by an exploding white dwarf star, no progenitor system has ever been directly observed. Significant effort has gone into searching for circumstellar material to help discriminate between the possible kinds of progenitor systems, but no such material has hitherto been found associated with a type Ia supernova. Here we report the presence of strong hydrogen emission associated with the type Ia supernova SN2002ic, indicating the presence of large amounts of circumstellar material. We infer from this that the progenitor system contained a massive asymptotic-giant-branch star that lost several solar masses of hydrogen-rich gas before the supernova explosion.

Supernovae in Early-Type Galaxies: Directly Connecting Age and Metallicity with Type Ia Luminosity

NASA Astrophysics Data System (ADS)

Gallagher, Joseph S.; Garnavich, Peter M.; Caldwell, Nelson; Kirshner, Robert P.; Jha, Saurabh W.; Li, Weidong; Ganeshalingam, Mohan; Filippenko, Alexei V.

2008-10-01

We have obtained optical spectra of 29 early-type (E/S0) galaxies that hosted Type Ia supernovae (SNe Ia). We have measured absorption-line strengths and compared them to a grid of models to extract the relations between the supernova properties and the luminosity-weighted age/composition of the host galaxies. Such a direct measurement is a marked improvement over existing analyses that tend to rely on general correlations between the properties of stellar populations and morphology. We find a strong correlation suggesting that SNe Ia in galaxies whose populations have a characteristic age greater than 5 Gyr are ~1 mag fainter at Vmax than those found in galaxies with younger populations. We find that SN Ia distance residuals in the Hubble diagram are correlated with host-galaxy metal abundance with higher iron abundance galaxies hosting less-luminous supernovae. We thus conclude that the time since progenitor formation primarily determines the radioactive Ni production while progenitor metal abundance has a weaker influence on peak luminosity, but one not fully corrected by light-curve shape and color fitters. This result, particularly the secondary dependence on metallicity, has significant implications for the determination of the equation-of-state parameter, w = P/(ρ c2) , and could impact planning for future dark-energy missions such as JDEM. Assuming no selection effects in discovering SNe Ia in local early-type galaxies, we find a higher specific SN Ia rate in E/S0 galaxies with ages below 3 Gyr than in older hosts. The higher rate and brighter luminosities seen in the youngest E/S0 hosts may be a result of recent star formation and represents a tail of the "prompt" SN Ia progenitors.

Immunoassay screening in urine for synthetic cannabinoids - an evaluation of the diagnostic efficiency.

PubMed

Franz, Florian; Angerer, Verena; Jechle, Hanna; Pegoro, Melanie; Ertl, Harald; Weinfurtner, Georg; Janele, David; Schlögl, Christian; Friedl, Matthias; Gerl, Stefan; Mielke, Reinhard; Zehnle, Ralf; Wagner, Matthias; Moosmann, Bjoern; Auwärter, Volker

2017-08-28

The abuse of synthetic cannabinoids (SCs) as presumed legal alternative to cannabis poses a great risk to public health. For economic reasons many laboratories use immunoassays (IAs) to screen for these substances in urine. However, the structural diversity and high potency of these designer drugs places high demands on IAs regarding cross-reactivity of the antibodies used and detection limits. Two retrospective studies were carried out in order to evaluate the capability of two homogenous enzyme IAs for the detection of currently prevalent SCs in authentic urine samples. Urine samples were analyzed utilizing a 'JWH-018' kit and a 'UR-144' kit. The IA results were confirmed by an up-to-date liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) screening method covering metabolites of 45 SCs. The first study (n=549) showed an 8% prevalence of SCs use (LC-MS/MS analysis) among inpatients of forensic-psychiatric clinics, whereas all samples were tested negative by the IAs. In a second study (n=200) the combined application of both IAs led to a sensitivity of 2% and a diagnostic accuracy of 51% when applying the recommended IA cut-offs. Overall, 10 different currently prevalent SCs were detected in this population. The results can be explained by an insufficient cross-reactivity of the antibodies towards current SCs in combination with relatively high detection limits of the IAs. In light of the presented study data it is strongly recommended not to rely on the evaluated IA tests for SCs in clinical or forensic settings. For IA kits of other providers similar results can be expected.

Type Ia supernovae, standardizable candles, and gravity

NASA Astrophysics Data System (ADS)

Wright, Bill S.; Li, Baojiu

2018-04-01

Type Ia supernovae (SNe Ia) are generally accepted to act as standardizable candles, and their use in cosmology led to the first confirmation of the as yet unexplained accelerated cosmic expansion. Many of the theoretical models to explain the cosmic acceleration assume modifications to Einsteinian general relativity which accelerate the expansion, but the question of whether such modifications also affect the ability of SNe Ia to be standardizable candles has rarely been addressed. This paper is an attempt to answer this question. For this we adopt a semianalytical model to calculate SNe Ia light curves in non-standard gravity. We use this model to show that the average rescaled intrinsic peak luminosity—a quantity that is assumed to be constant with redshift in standard analyses of Type Ia supernova (SN Ia) cosmology data—depends on the strength of gravity in the supernova's local environment because the latter determines the Chandrasekhar mass—the mass of the SN Ia's white dwarf progenitor right before the explosion. This means that SNe Ia are no longer standardizable candles in scenarios where the strength of gravity evolves over time, and therefore the cosmology implied by the existing SN Ia data will be different when analysed in the context of such models. As an example, we show that the observational SN Ia cosmology data can be fitted with both a model where (ΩM,ΩΛ)=(0.62 ,0.38 ) and Newton's constant G varies as G (z )=G0(1 +z )-1/4 and the standard model where (ΩM,ΩΛ)=(0.3 ,0.7 ) and G is constant, when the Universe is assumed to be flat.

Multidimensional Models of Type Ia Supernova Nebular Spectra: Strong Emission Lines from Stripped Companion Gas Rule Out Classic Single-degenerate Systems

NASA Astrophysics Data System (ADS)

Botyánszki, János; Kasen, Daniel; Plewa, Tomasz

2018-01-01

The classic single-degenerate model for the progenitors of Type Ia supernova (SN Ia) predicts that the supernova ejecta should be enriched with solar-like abundance material stripped from the companion star. Spectroscopic observations of normal SNe Ia at late times, however, have not resulted in definite detection of hydrogen. In this Letter, we study line formation in SNe Ia at nebular times using non-LTE spectral modeling. We present, for the first time, multidimensional radiative transfer calculations of SNe Ia with stripped material mixed in the ejecta core, based on hydrodynamical simulations of ejecta–companion interaction. We find that interaction models with main-sequence companions produce significant Hα emission at late times, ruling out these types of binaries being viable progenitors of SNe Ia. We also predict significant He I line emission at optical and near-infrared wavelengths for both hydrogen-rich or helium-rich material, providing an additional observational probe of stripped ejecta. We produce models with reduced stripped masses and find a more stringent mass limit of M st ≲ 1 × 10‑4 M ⊙ of stripped companion material for SN 2011fe.

Type II decompression sickness in a hyperbaric inside attendant.

PubMed

Johnson-Arbor, Kelly

2012-01-01

Decompression sickness (DCS) of an inside attendant (IA) is rarely encountered in hyperbarics. This report describes an IA who developed Type II DCS after a routine hyperbaric exposure. A 50-year-old male complained of lower extremity weakness and paresthesias after serving as an IA during a hyperbaric treatment to 40 fsw (122.52 kPa). Within 10 minutes after the conclusion of the treatment, the IA experienced irritability and confusion, and was unable to walk. Physical examination revealed decreased sensation below the T7 level, and decreased strength in the lower extremities. Type II DCS was diagnosed, and the IA was recompressed to 60 fsw (183.78 kPa) on a U.S. Navy Treatment Table 6, which resulted in improvement of his symptoms. Transthoracic echocardiography with bubble study performed 16 months after the event demonstrated a large patent foramen ovale (PFO). Increased age, decreased physical fitness and the undiagnosed PFO may have predisposed this attendant to developing DCS. Although rare, DCS may occur in IAs. Routine monitoring and reporting of the long-term health of hyperbaric IAs should be considered by hyperbaric facilities and medical directors in order to further understand the characteristics of DCS and other hyperbaric-related conditions in these workers.

Calibrating the Type Ia Supernova Distance Scale Using Surface Brightness Fluctuations

NASA Astrophysics Data System (ADS)

Potter, Cicely; Jensen, Joseph B.; Blakeslee, John; Milne, Peter; Garnavich, Peter M.; Brown, Peter

2018-06-01

We have observed 20 supernova host galaxies with HST WFC3/IR in the F110W filter, and prepared the data for Surface Brightness Fluctuation (SBF) distance measurements. The purpose of this study is to determine if there are any discrepancies between the SBF distance scale and the type-Ia SN distance scale, for which local calibrators are scarce. We have now measured SBF magnitudes to all early-type galaxies that have hosted SN Ia within 80 Mpc for which SBF measurements are possible. SBF is the only distance measurement technique with statistical uncertainties comparable to SN Ia that can be applied to galaxies out to 80 Mpc.

Ages, chemistry, and type 1A supernovae: Clues to the formation of the galactic stellar halo

NASA Technical Reports Server (NTRS)

Smecker-Hane, Tammy A.; Wyse, Rosemary F. G.

1993-01-01

We endeavor to resolve two conflicting constraints on the duration of the formation of the Galactic stellar halo - 2-3 Gyr age differences in halo stars, and the time scale inferred from the observed constant values of chemical element abundance ratios characteristic of enrichment by Type II supernovae - by investigating the time scale for the onset of Type Ia supernovae (SNIa) in the currently favored progenitor model - mergers of carbon and oxygen white dwarfs (CO WDs).

The Progenitor of Tycho’s Supernova was Not Hot and Luminous

NASA Astrophysics Data System (ADS)

Ghavamian, Parviz; Woods, T. E.; Gilfanov, M.; Badenes, C.; T. E. Woods, C. Badenes, M. Gilfanov

2018-01-01

Canonical accretion models of Type Ia supernovae predict that a hot and luminous progenitor will ionize the surrounding gas out to a radius of ∼10–100 pc for ∼100,000 years after the explosion. Tycho’s supernova of 1572 was a Type Ia explosion which produced a remnant that is currently interacting with neutral gas in the form of Balmer-dominated shocks. From analysis of these shocks and photoionization calculations, we have placed stringent upper limits on the temperature and luminosity of the progenitor of Tycho’s supernova. Hot, luminous progenitors that would have produced a greater hydrogen ionization fraction than that measured at the current SNR radius (∼3 parsecs) can thus be excluded. This rules out steadily nuclear-burning white dwarfs (i..e, supersoft X-ray sources), as well as disk emission from a Chandrasekhar-mass white dwarf accreting 1E-8 solar masses per year (recurrent novae). The lack of a Stromgren sphere around Tycho’s SNR is consistent with a double degenerate explosion, although other more exotic scenarios may be possible.

Galaxy clusters, type Ia supernovae and the fine structure constant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holanda, R.F.L.; Busti, V.C.; Colaço, L.R.

2016-08-01

As is well known, measurements of the Sunyaev-Zeldovich effect can be combined with observations of the X-ray surface brightness of galaxy clusters to estimate the angular diameter distance to these structures. In this paper, we show that this technique depends on the fine structure constant, α. Therefore, if α is a time-dependent quantity, e.g., α = α{sub 0}φ( z ), where φ is a function of redshift, we argue that current data do not provide the real angular diameter distance, D {sub A}( z ), to the cluster, but instead D {sub A}{sup data}( z ) = φ( z ){supmore » 2} D {sub A}( z ). We use this result to derive constraints on a possible variation of α for a class of dilaton runaway models considering a sample of 25 measurements of D {sub A}{sup data}( z ) in redshift range 0.023 < z < 0.784 and estimates of D {sub A}( z ) from current type Ia supernovae observations. We find no significant indication of variation of α with the present data.« less

Central Elemental Abundance Ratios In the Perseus Cluster: Resonant Scattering or SN Ia Enrichment?

NASA Technical Reports Server (NTRS)

Dupke, Renato A.; Arnaud, Keith; White, Nicholas E. (Technical Monitor)

2001-01-01

We have determined abundance ratios in the core of the Perseus Cluster for several elements. These ratios indicate a central dominance of Type 1a supernova (SN Ia) ejects similar to that found for A496, A2199 and A3571. Simultaneous analysis of ASCA spectra from SIS1, GIS2, and GIS3 shows that the ratio of Ni to Fe abundances is approx. 3.4 +/- 1.1 times solar within the central 4'. This ratio is consistent with (and more precise than) that observed in other clusters whose central regions are dominated by SN Ia ejecta. Such a large Ni overabundance is predicted by "convective deflagration" explosion models for SNe Ia such as W7 but is inconsistent with delayed detonation models. We note that with current instrumentation the Ni K(alpha) line is confused with Fe K(beta) and that the Ni overabundance we observe has been interpreted by others as an anomalously large ratio of Fe K(beta) to Fe K(alpha) caused by resonant scattering in the Fe K(alpha) line. We argue that a central enhancement of SN Ia ejecta and hence a high ratio of Ni to Fe abundances are naturally explained by scenarios that include the generation of chemical gradients by suppressed SN Ia winds or ram pressure stripping of cluster galaxies. It is not necessary to suppose that the intracluster gas is optically thick to resonant scattering of the Fe K(alpha) line.

L-type voltage-dependent calcium channel is involved in the snake venom group IA secretory phospholipase A2-induced neuronal apoptosis.

PubMed

Yagami, Tatsurou; Yamamoto, Yasuhiro; Kohma, Hiromi; Nakamura, Tsutomu; Takasu, Nobuo; Okamura, Noboru

2013-03-01

Snake venom group IA secretory phospholipase A2 (sPLA2-IA) is known as a neurotoxin. Snake venom sPLA2s are neurotoxic in vivo and in vitro, causing synergistic neurotoxicity to cortical cultures when applied with toxic concentrations of glutamate. However, it has not yet been cleared sufficiently how sPLA2-IA exerts neurotoxicity. Here, we found sPLA2-IA induced neuronal cell death in a concentration-dependent manner. This death was a delayed response requiring a latent time for 6h. sPLA2-IA-induced neuronal cell death was accompanied with apoptotic blebbing, condensed chromatin, and fragmented DNA, exhibiting apoptotic features. NMDA receptor blockers suppressed the neurotoxicity of sPLA2-IA, but an AMPA receptor blocker did not. Interestingly, L-type voltage-dependent Ca(2+) channel (L-VDCC) blocker significantly protected neurons from the sPLA2-IA-induced apoptosis. On the other hand, neither N-VDCC blockers nor P/Q-VDCC blocker did. In conclusion, we demonstrated that sPLA2-IA induced neuronal cell death via apoptosis. Furthermore, the present study suggests that not only NMDA receptor but also L-VDCC contributed to the neurotoxicity of snake venom sPLA2-IA. Copyright © 2013 Elsevier Inc. All rights reserved.

Persistent escalation of alcohol drinking in C57BL/6J mice with intermittent access to 20% ethanol.

PubMed

Hwa, Lara S; Chu, Adam; Levinson, Sally A; Kayyali, Tala M; DeBold, Joseph F; Miczek, Klaus A

2011-11-01

Intermittent access (IA) to drugs of abuse, as opposed to continuous access, is hypothesized to induce a kindling-type transition from moderate to escalated use, leading to dependence. Intermittent 24-hour cycles of ethanol access and deprivation can generate high levels of voluntary ethanol drinking in rats. The current study uses C57BL/6J mice (B6) in an IA to 20% ethanol protocol to escalate ethanol drinking levels. Adult male and female B6 mice were given IA to 20% ethanol on alternating days of the week with water available ad libitum. Ethanol consumption during the initial 2 hours of access was compared with a short-term, limited access "binge" drinking procedure, similar to drinking-in-the-dark (DID). B6 mice were also assessed for ethanol dependence with handling-induced convulsion, a reliable measure of withdrawal severity. After 3 weeks, male mice given IA to ethanol achieved high stable levels of ethanol drinking in excess of 20 g/kg/24 h, reaching above 100 mg/dl blood ethanol concentrations, and showed a significantly higher ethanol preference than mice given continuous access to ethanol. Also, mice given IA drank about twice as much as DID mice in the initial 2-hour access period. B6 mice that underwent the IA protocol for longer periods of time displayed more severe signs of alcohol withdrawal. Additionally, female B6 mice were given IA to ethanol and drank significantly more than males (ca. 30 g/kg/24 h). The IA method in B6 mice is advantageous because it induces escalated, voluntary, and preferential per os ethanol intake, behavior that may mimic a cardinal feature of human alcohol dependence, though the exact nature and site of ethanol acting in the brain and blood as a result of IA has yet to be determined. Copyright © 2011 by the Research Society on Alcoholism.

A Model-independent Photometric Redshift Estimator for Type Ia Supernovae

NASA Astrophysics Data System (ADS)

Wang, Yun

2007-01-01

The use of Type Ia supernovae (SNe Ia) as cosmological standard candles is fundamental in modern observational cosmology. In this Letter, we derive a simple empirical photometric redshift estimator for SNe Ia using a training set of SNe Ia with multiband (griz) light curves and spectroscopic redshifts obtained by the Supernova Legacy Survey (SNLS). This estimator is analytical and model-independent it does not use spectral templates. We use all the available SNe Ia from SNLS with near-maximum photometry in griz (a total of 40 SNe Ia) to train and test our photometric redshift estimator. The difference between the estimated redshifts zphot and the spectroscopic redshifts zspec, (zphot-zspec)/(1+zspec), has rms dispersions of 0.031 for 20 SNe Ia used in the training set, and 0.050 for 20 SNe Ia not used in the training set. The dispersion is of the same order of magnitude as the flux uncertainties at peak brightness for the SNe Ia. There are no outliers. This photometric redshift estimator should significantly enhance the ability of observers to accurately target high-redshift SNe Ia for spectroscopy in ongoing surveys. It will also dramatically boost the cosmological impact of very large future supernova surveys, such as those planned for the Advanced Liquid-mirror Probe for Astrophysics, Cosmology, and Asteroids (ALPACA) and the Large Synoptic Survey Telescope (LSST).

Two classes of fast-declining Type Ia supernovae

NASA Astrophysics Data System (ADS)

Dhawan, Suhail; Leibundgut, B.; Spyromilio, J.; Blondin, S.

2017-06-01

We aim to characterise a sample of fast-declining Type Ia supernovae (SN Ia) using their bolometric and near-infrared (NIR) properties. Based on these properties, we find that fast-declining SN Ia separate into two categories based on their bolometric and NIR properties. The peak bolometric luminosity (Lmax), the phase of the first maximum relative to the optical, the NIR peak luminosity, and the occurrence of a second maximum in the NIR distinguish a group of very faint SN Ia. Fast-declining supernovae show a large range of peak bolometric luminosities (Lmax differing by up to a factor of 8). All fast-declining SN Ia with Lmax < 0.3× 1043 erg s-1 are spectroscopically classified as 91bg-like and show only a single NIR peak. SNe with Lmax > 0.5× 1043 erg s-1 appear to smoothly connect to normal SN Ia. The total ejecta mass (Mej) values for SNe with enough late time data are ≲1 M⊙, indicating a sub-Chandrasekhar mass progenitor for these SNe.

Cosmological constraints from measurements of type Ia supernovae discovered during the first 1.5 yr of the Pan-STARRS1 survey

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rest, A.; Scolnic, D.; Riess, A.

2014-11-01

We present griz {sub P1} light curves of 146 spectroscopically confirmed Type Ia supernovae (SNe Ia; 0.03 < z < 0.65) discovered during the first 1.5 yr of the Pan-STARRS1 Medium Deep Survey. The Pan-STARRS1 natural photometric system is determined by a combination of on-site measurements of the instrument response function and observations of spectrophotometric standard stars. We find that the systematic uncertainties in the photometric system are currently 1.2% without accounting for the uncertainty in the Hubble Space Telescope Calspec definition of the AB system. A Hubble diagram is constructed with a subset of 113 out of 146 SNemore » Ia that pass our light curve quality cuts. The cosmological fit to 310 SNe Ia (113 PS1 SNe Ia + 222 light curves from 197 low-z SNe Ia), using only supernovae (SNe) and assuming a constant dark energy equation of state and flatness, yields w=−1.120{sub −0.206}{sup +0.360}(Stat){sub −0.291}{sup +0.269}(Sys). When combined with BAO+CMB(Planck)+H {sub 0}, the analysis yields Ω{sub M}=0.280{sub −0.012}{sup +0.013} and w=−1.166{sub −0.069}{sup +0.072} including all identified systematics. The value of w is inconsistent with the cosmological constant value of –1 at the 2.3σ level. Tension endures after removing either the baryon acoustic oscillation (BAO) or the H {sub 0} constraint, though it is strongest when including the H {sub 0} constraint. If we include WMAP9 cosmic microwave background (CMB) constraints instead of those from Planck, we find w=−1.124{sub −0.065}{sup +0.083}, which diminishes the discord to <2σ. We cannot conclude whether the tension with flat ΛCDM is a feature of dark energy, new physics, or a combination of chance and systematic errors. The full Pan-STARRS1 SN sample with ∼three times as many SNe should provide more conclusive results.« less

Proteomic analysis highlights the molecular complexities of native Kv4 channel macromolecular complexes.

PubMed

Marionneau, Céline; Townsend, R Reid; Nerbonne, Jeanne M

2011-04-01

Voltage-gated K(+) (Kv) channels are key determinants of membrane excitability in the nervous and cardiovascular systems, functioning to control resting membrane potentials, shape action potential waveforms and influence the responses to neurotransmitters and neurohormones. Consistent with this functional diversity, multiple types of Kv currents, with distinct biophysical properties and cellular/subcellular distributions, have been identified. Rapidly activating and inactivating Kv currents, typically referred to as I(A) (A-type) in neurons, for example, regulate repetitive firing rates, action potential back-propagation (into dendrites) and modulate synaptic responses. Currents with similar properties, referred to as I(to,f) (fast transient outward), expressed in cardiomyocytes, control the early phase of myocardial action potential repolarization. A number of studies have demonstrated critical roles for pore-forming (α) subunits of the Kv4 subfamily in the generation of native neuronal I(A) and cardiac I(to,f) channels. Studies in heterologous cells have also suggested important roles for a number of Kv channel accessory and regulatory proteins in the generation of functional I(A) and I(to,f) channels. Quantitative mass spectrometry-based proteomic analysis is increasingly recognized as a rapid and, importantly, unbiased, approach to identify the components of native macromolecular protein complexes. The recent application of proteomic approaches to identify the components of native neuronal (and cardiac) Kv4 channel complexes has revealed even greater complexity than anticipated. The continued emphasis on development of improved biochemical and analytical proteomic methods seems certain to accelerate progress and to provide important new insights into the molecular determinants of native ion channel protein complexes. Copyright © 2010 Elsevier Ltd. All rights reserved.

Determination of Endograft Apposition, Position, and Expansion in the Aortic Neck Predicts Type Ia Endoleak and Migration After Endovascular Aneurysm Repair.

PubMed

Schuurmann, Richte C L; van Noort, Kim; Overeem, Simon P; van Veen, Ruben; Ouriel, Kenneth; Jordan, William D; Muhs, Bart E; 't Mannetje, Yannick W; Reijnen, Michel M P J; Fioole, Bram; Ünlü, Çağdaş; Brummel, Peter; de Vries, Jean-Paul P M

2018-06-01

To describe the added value of determining changes in position and apposition on computed tomography angiography (CTA) after endovascular aneurysm repair (EVAR) to detect early caudal displacement of the device and to prevent type Ia endoleak. Four groups of elective EVAR patients were selected from a dataset purposely enriched with type Ia endoleak and migration (>10 mm) cases. The groups included cases of late type Ia endoleak (n=36), migration (n=9), a type II endoleak (n=16), and controls without post-EVAR complications (n=37). Apposition of the endograft fabric with the aortic neck, shortest distance between the fabric and the renal arteries, expansion of the main body (or dilatation of the aorta in the infrarenal sealing zone), and tilt of the endograft toward the aortic axis were determined on the first postoperative and the last available CTA scan without type Ia endoleak or migration. Differences in these endograft dimensions were compared between the first vs last scan and among the 4 groups. No significant differences in endograft configurations were observed among the groups on the first postoperative CTA scan. On the last CTA scan before a complication arose, the position of the fabric relative to the renal arteries, expansion of the main body, and apposition of the fabric with the aortic neck were significantly different between the type Ia endoleak (median follow-up 15 months) and migration groups (median follow-up 23 months) compared with the control group (median follow-up 19 months). Most endograft dimensions had changed significantly compared with the first postoperative CTA scan for all groups. Apposition had increased in the control group but had decreased significantly in the type Ia endoleak and migration groups. Progressive changes in dimensions of the endograft within the infrarenal neck could be detected on regular CTA scans before the complication became urgent in many patients.

Lensed Type Ia supernovae as probes of cluster mass models

Science.gov Websites

SAO/NASA ADS Astronomy Abstract Service Title: Lensed Type Ia supernovae as probes of cluster mass Origin: OUP Astronomy Keywords: gravitational lensing: strong, supernovae: general, galaxies: clusters

Co-regulation of intragenic microRNA miR-153 and its host gene Ia-2 β: identification of miR-153 target genes with functions related to IA-2β in pancreas and brain.

PubMed

Mandemakers, W; Abuhatzira, L; Xu, H; Caromile, L A; Hébert, S S; Snellinx, A; Morais, V A; Matta, S; Cai, T; Notkins, A L; De Strooper, B

2013-07-01

We analysed the genomic organisation of miR-153, a microRNA embedded in genes that encode two of the major type 1 diabetes autoantigens, islet-associated protein (IA)-2 and IA-2β. We also identified miR-153 target genes that correlated with IA-2β localisation and function. A bioinformatics approach was used to identify miR-153's genomic organisation. To analyse the co-regulation of miR-153 and IA-2β, quantitative PCR analysis of miR-153 and Ia-2β (also known as Ptprn2) was performed after a glucose stimulation assay in MIN6B cells and isolated murine pancreatic islets, and also in wild-type Ia-2 (also known as Ptprn), Ia-2β single knockout and Ia-2/Ia-2β double knockout mouse brain and pancreatic islets. Bioinformatics identification of miR-153 target genes and validation via luciferase reporter assays, western blotting and quantitative PCR were also carried out. Two copies of miR-153, miR-153-1 and miR-153-2, are localised in intron 19 of Ia-2 and Ia-2β, respectively. In rodents, only miR-153-2 is conserved. We demonstrated that expression of miR-153-2 and Ia-2β in rodents is partially co-regulated as demonstrated by a strong reduction of miR-153 expression levels in Ia-2β knockout and Ia-2/Ia-2β double knockout mice. miR-153 levels were unaffected in Ia-2 knockout mice. In addition, glucose stimulation, which increases Ia-2 and Ia-2β expression, also significantly increased expression of miR-153. Several predicted targets of miR-153 were reduced after glucose stimulation in vitro, correlating with the increase in miR-153 levels. This study suggests the involvement of miR-153, IA-2β and miR-153 target genes in a regulatory network, which is potentially relevant to insulin and neurotransmitter release.

SN 1991bg - A type Ia supernova with a difference

NASA Technical Reports Server (NTRS)

Leibundgut, Bruno; Kirshner, Robert P.; Phillips, Mark M.; Wells, Lisa A.; Suntzeff, N. B.; Hamuy, Mario; Schommer, R. A.; Walker, A. R.; Gonzalez, L.; Ugarte, P.

1993-01-01

While SN 1991bg is an unusual type Ia SN in such a feature as the brief duration of the photospheric phase, which ended only two weeks after maximum, it shares with other Ia SNs strong Si II and Ca II lines near maximum light. In addition, the light and color curve slopes are almost identical with the templates at late times. The spectral evolution of SN 1991bg is also unique but not unrecognizable; nevertheless, the peculiarities associated with this event complicate the fundamental question as to whether the Ia SNs make good standard candles.

HOW TO FIND GRAVITATIONALLY LENSED TYPE Ia SUPERNOVAE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldstein, Daniel A.; Nugent, Peter E.

2017-01-01

Type Ia supernovae (SNe Ia) that are multiply imaged by gravitational lensing can extend the SN Ia Hubble diagram to very high redshifts ( z ≳ 2), probe potential SN Ia evolution, and deliver high-precision constraints on H {sub 0}, w , and Ω{sub m} via time delays. However, only one, iPTF16geu, has been found to date, and many more are needed to achieve these goals. To increase the multiply imaged SN Ia discovery rate, we present a simple algorithm for identifying gravitationally lensed SN Ia candidates in cadenced, wide-field optical imaging surveys. The technique is to look for supernovaemore » that appear to be hosted by elliptical galaxies, but that have absolute magnitudes implied by the apparent hosts’ photometric redshifts that are far brighter than the absolute magnitudes of normal SNe Ia (the brightest type of supernovae found in elliptical galaxies). Importantly, this purely photometric method does not require the ability to resolve the lensed images for discovery. Active galactic nuclei, the primary sources of contamination that affect the method, can be controlled using catalog cross-matches and color cuts. Highly magnified core-collapse SNe will also be discovered as a byproduct of the method. Using a Monte Carlo simulation, we forecast that the Large Synoptic Survey Telescope can discover up to 500 multiply imaged SNe Ia using this technique in a 10 year z -band search, more than an order of magnitude improvement over previous estimates. We also predict that the Zwicky Transient Facility should find up to 10 multiply imaged SNe Ia using this technique in a 3 year R -band search—despite the fact that this survey will not resolve a single system.« less

Erythrocyte membrane docosapentaenoic acid levels are associated with islet autoimmunity: The Diabetes Autoimmunity Study in the Young

PubMed Central

Norris, Jill M.; Kroehl, Miranda; Fingerlin, Tasha E.; Frederiksen, Brittni N.; Seifert, Jennifer; Wong, Randall; Clare-Salzler, Michael; Rewers, Marian

2013-01-01

Aims/hypotheses We previously reported that lower n-3 fatty acid intake and levels in erythrocyte membranes were associated with increased risk of islet autoimmunity (IA) but not progression to type 1 diabetes in children at increased risk for diabetes. We hypothesise that specific n-3 fatty acids and genetic markers contribute synergistically to this increased risk of IA in the Diabetes Autoimmunity Study in the Young (DAISY). Methods DAISY is following 2547 children at increased risk for type 1 diabetes for the development of IA, defined as being positive for glutamic acid decarboxylase (GAD)65, IA-2 or insulin autoantibodies on two consecutive visits. Using a case-cohort design, erythrocyte membrane fatty acids and dietary intake were measured prospectively in 58 IA-positive children and 299 IA-negative children. Results Lower membrane levels of the n-3 fatty acid, docosapentaenoic acid (DPA), were predictive of IA (HR 0.23; 95% CI 0.09,0.55), while alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were not, adjusting for HLA and diabetes family history. We examined whether the effect of dietary intake of the n-3 fatty acid ALA on IA risk was modified by fatty acid elongation and desaturation genes. Adjusting for HLA, diabetes family history, ethnicity, energy intake and questionnaire type, ALA intake was significantly more protective for IA in the presence of an increasing number of minor alleles at FADS1 rs174556 (pinteraction=0.017), at FADS2 rs174570 (pinteraction=0.016) and at FADS2 rs174583 (pinteraction=0.045). Conclusions/interpretation The putative protective effect of n-3 fatty acids on IA may result from a complex interaction between intake and genetically-controlled fatty acid desaturation. PMID:24240437

EARLY-PHASE PHOTOMETRY AND SPECTROSCOPY OF TRANSITIONAL TYPE Ia SN 2012ht: DIRECT CONSTRAINT ON THE RISE TIME

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamanaka, Masayuki; Nogami, Daisaku; Maeda, Keiichi

We report photometric and spectroscopic observations of the nearby Type Ia Supernova (SN Ia) 2012ht from –15.8 days to +49.1 days after B-band maximum. The decline rate of the light curve is Δm {sub 15}(B) = 1.39 ± 0.05 mag, which is intermediate between normal and subluminous SNe Ia, and similar to that of the ''transitional'' Type Ia SN 2004eo. The spectral line profiles also closely resemble those of SN 2004eo. We were able to observe SN 2012ht at a very early phase, when it was still rising and was about three magnitudes fainter than at the peak. The rise time to the B-bandmore » maximum is estimated to be 17.6 ± 0.5 days and the time of the explosion is MJD 56277.98 ± 0.13. SN 2012ht is the first transitional SN Ia whose rise time is directly measured without using light curve templates, and the fifth SN Ia overall. This rise time is consistent with those of the other four SNe within the measurement error, even including the extremely early detection of SN 2013dy. The rising part of the light curve can be fitted by a quadratic function, and shows no sign of a shock-heating component due to the interaction of the ejecta with a companion star. The rise time is significantly longer than that inferred for subluminous SNe such as SN 1991bg, which suggests that a progenitor and/or explosion mechanism of transitional SNe Ia are more similar to normal SNe Ia rather than to subluminous SNe Ia.« less

How to Find Gravitationally Lensed Type Ia supernovae

DOE PAGES

Goldstein, Daniel A.; Nugent, Peter E.

2016-12-29

Type Ia supernovae (SNe Ia) that are multiply imaged by gravitational lensing can extend the SN Ia Hubble diagram to very high redshifts (z ≳ 2), probe potential SN Ia evolution, and deliver high-precision constraints on H 0, w, and Ω m via time delays. However, only one, iPTF16geu, has been found to date, and many more are needed to achieve these goals. To increase the multiply imaged SN Ia discovery rate, we present a simple algorithm for identifying gravitationally lensed SN Ia candidates in cadenced, wide-field optical imaging surveys. The technique is to look for supernovae that appear tomore » be hosted by elliptical galaxies, but that have absolute magnitudes implied by the apparent hosts' photometric redshifts that are far brighter than the absolute magnitudes of normal SNe Ia (the brightest type of supernovae found in elliptical galaxies). Importantly, this purely photometric method does not require the ability to resolve the lensed images for discovery. Active galactic nuclei, the primary sources of contamination that affect the method, can be controlled using catalog cross-matches and color cuts. Highly magnified core-collapse SNe will also be discovered as a byproduct of the method. Using a Monte Carlo simulation, we forecast that the Large Synoptic Survey Telescope can discover up to 500 multiply imaged SNe Ia using this technique in a 10 year z-band search, more than an order of magnitude improvement over previous estimates. Finally, we also predict that the Zwicky Transient Facility should find up to 10 multiply imaged SNe Ia using this technique in a 3 year R-band search - despite the fact that this survey will not resolve a single system.« less

UNITY: Confronting Supernova Cosmology's Statistical and Systematic Uncertainties in a Unified Bayesian Framework

NASA Astrophysics Data System (ADS)

Rubin, D.; Aldering, G.; Barbary, K.; Boone, K.; Chappell, G.; Currie, M.; Deustua, S.; Fagrelius, P.; Fruchter, A.; Hayden, B.; Lidman, C.; Nordin, J.; Perlmutter, S.; Saunders, C.; Sofiatti, C.; Supernova Cosmology Project, The

2015-11-01

While recent supernova (SN) cosmology research has benefited from improved measurements, current analysis approaches are not statistically optimal and will prove insufficient for future surveys. This paper discusses the limitations of current SN cosmological analyses in treating outliers, selection effects, shape- and color-standardization relations, unexplained dispersion, and heterogeneous observations. We present a new Bayesian framework, called UNITY (Unified Nonlinear Inference for Type-Ia cosmologY), that incorporates significant improvements in our ability to confront these effects. We apply the framework to real SN observations and demonstrate smaller statistical and systematic uncertainties. We verify earlier results that SNe Ia require nonlinear shape and color standardizations, but we now include these nonlinear relations in a statistically well-justified way. This analysis was primarily performed blinded, in that the basic framework was first validated on simulated data before transitioning to real data. We also discuss possible extensions of the method.

Aortic curvature as a predictor of intraoperative type Ia endoleak.

PubMed

Schuurmann, Richte C L; Ouriel, Kenneth; Muhs, Bart E; Jordan, William D; Ouriel, Richard L; Boersen, Johannes T; de Vries, Jean-Paul P M

2016-03-01

Hostile infrarenal neck characteristics are associated with complications such as type Ia endoleak after endovascular aneurysm repair. Aortic neck angulation has been identified as one such characteristic, but its association with complications has not been uniform between studies. Neck angulation assumes triangular oversimplification of the aortic trajectory, which may explain conflicting findings. By contrast, aortic curvature is a measurement that includes the bending rate and tortuosity and may provide better predictive value for neck complications. Data were retrieved from the Heli-FX (Aptus Endosystems, Inc, Sunnyvale, Calif) Aortic Securement System Global Registry (ANCHOR). One cohort included patients who presented with intraoperative endoleak type Ia at the completion angiogram as the indication for EndoAnchors (Aptus Endosystems), and a second cohort comprised those without intraoperative or late type Ia endoleak (controls). The aortic trajectory was divided into six segments with potentially different influence on the stent graft performance: suprarenal, juxtarenal, and infrarenal aortic neck (-30 to -10 mm, -10 to 10 mm, and 10-30 mm from the lowest renal artery, respectively), the entire aortic neck, aneurysm sac, and terminal aorta (20 mm above the bifurcation to the bifurcation). Maximum and average curvature were automatically calculated over the six segments by proprietary custom software. Aortic curvature was compared with other standard neck characteristics, including neck length, neck diameter, maximum aneurysm sac diameter, neck thrombus and calcium thickness and circumference, suprarenal angulation, infrarenal angulation, and the neck tortuosity index. Independent risk factors for intraoperative type Ia endoleak were identified using backwards stepwise logistic regression. For the variables in the final regression model, suitable cutoff values in relation to the prediction of acute type Ia endoleak were defined with the area under the receiver operating characteristic curve. The analysis included 64 patients with intraoperative type Ia endoleak and 79 controls. Logistic regression identified only aortic neck calcification and aortic curvature, expressed over the juxtarenal aortic neck, the aneurysm sac, and the terminal aorta, as independent predictors of intraoperative type Ia endoleak. Together with aortic neck calcification, aortic curvature appears to be the best predictor of intraoperative type Ia endoleak, as expressed within the juxtarenal aortic neck, the aneurysm sac, and the terminal aorta. Aortic neck angulation was not a predictor for acute failure. Aortic curvature may provide a better anatomic characteristic to define patients at risk for early complications after endovascular aneurysm repair. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Swift X-Ray Upper Limits on Type Ia Supernova Environments

NASA Technical Reports Server (NTRS)

Russell, B. R.; Immler, S.

2012-01-01

We have considered 53 Type Ia supernovae (SNe Ia) observed by the Swift X-Ray Telescope. None of the SNe Ia are individually detected at any time or in stacked images. Using these data and assuming that the SNe Ia are a homogeneous class of objects, we have calculated upper limits to the X-ray luminosity (0.2-10 keV) and mass-loss rate of L(sub 0.2-10) < 1.7 X 10(exp 38) erg/s and M(dot) < l.l X 10(exp -6) solar M/ yr x (V(sub w))/(10 km/s), respectively. The results exclude massive or evolved stars as the companion objects in SN Ia progenitor systems, but allow the possibility of main sequence or small stars, along with double degenerate systems consisting of two white dwarfs, consistent with results obtained at other wavelengths (e.g., UV, radio) in other studies.

4-aminopyridine, a Kv channel antagonist, prevents apoptosis of rat cerebellar granule neurons.

PubMed

Hu, Chang-Long; Liu, Zheng; Zeng, Xi-Min; Liu, Zi-Qiang; Chen, Xian-Hua; Zhang, Zhi-Hong; Mei, Yan-Ai

2006-09-01

Compelling evidence indicates that excessive potassium (K+) efflux and intracellular K+ depletion are the key early steps in apoptosis. Previously, we reported that apoptosis of cerebellar granule neurons induced by incubation in low-K+ (5 mM) and serum-free medium was associated with an increase in A-type transient inactivation of K+ channel current (IA) amplitude and modulation of channels' gating properties. Here, we showed that a classic K+ channel blocker, 4-aminopyradine (4-AP), significantly inhibited IA amplitude in a concentration-dependent manner (reduction of current by 10 microM and 10 mM 4-AP was 11.4+/-1.3% and 72.2+/-3.3%, respectively). Moreover, 4-AP modified the steady-state activation and inactivation kinetics of IA channels, such that the activation and inactivation curves were shifted to the right about 20 mV and 17 mV, respectively. Fluorescence staining showed that 4-AP dramatically increased the viability of cells undergoing apoptosis in a dose-dependent manner. That is, while 5 mM 4-AP was present, cell viability was 84.9+/-5.2%. Consistent with the cell viability analysis, internucleosomal DNA fragmentation by gel electrophoresis analysis showed that 5 mM 4-AP also protected against neuronal apoptosis. Furthermore, 4-AP significantly inhibited cytochrome c release and caspase-3 activity induced by low-K+/serum-free incubation. Finally, current-clamp analysis indicated that 5 mM 4-AP did not significantly depolarize the membrane potential. These results suggest that 4-AP has robust neuroprotective effects on apoptotic granule cells. The neuroprotective effect of 4-AP is likely not due to membrane depolarization, but rather that 4-AP may modulate the gating properties of IA channels in an anti-apoptotic manner.

Is Local Viscosupplementation Injection Clinically Superior to Other Therapies in the Treatment of Osteoarthritis of the Knee: A Systematic Review of Overlapping Meta-analyses.

PubMed

Campbell, Kirk A; Erickson, Brandon J; Saltzman, Bryan M; Mascarenhas, Randy; Bach, Bernard R; Cole, Brian J; Verma, Nikhil N

2015-10-01

To conduct a systematic review of overlapping meta-analyses comparing treatment of knee osteoarthritis (OA) with intra-articular viscosupplementation (intra-articular hyaluronic acid [IA-HA]) versus oral nonsteroidal anti-inflammatory drugs (NSAIDs), intra-articular corticosteroids (IA-corticosteroids), intra-articular platelet-rich plasma (IA-PRP), or intra-articular placebo (IA-placebo) to determine which meta-analyses provide the best current evidence and identify potential causes of discordance. Literature searches were performed for meta-analyses examining use of IA-HA versus NSAIDs, IA-corticosteroids, IA-PRP, or IA-placebo. Clinical data were extracted, and meta-analysis quality was assessed. The Jadad algorithm was applied to determine which meta-analyses provided the highest level of evidence. Fourteen meta-analyses met the eligibility criteria and ranged in quality from Level I to IV evidence. In studies reporting patient numbers, there were a total of 20,049 patients: 13,698 receiving IA-HA, 355 receiving NSAIDs, 294 receiving IA-corticosteroids, and 5,702 receiving IA-placebo. Ten studies examined the effects of IA-HA versus IA-placebo; of these, 5 found that IA-HA improved pain and 4 found that IA-HA improved function. No clinically relevant differences in the efficacy of IA-HA versus NSAIDs regarding pain and function were found. Regarding IA-HA versus IA-PRP, IA-HA improved knee function at 2 and 6 months after injection but the effects were less robust than those of IA-PRP. Regarding IA-HA versus IA-corticosteroids, the positive effects of IA-HA were greater at 5 to 13 weeks and persisted for up to 26 weeks. After application of the Jadad algorithm, 2 concordant high-quality meta-analyses were selected and both showed that IA-HA provided clinically relevant improvements in pain and function compared with IA-placebo. This systematic review of overlapping meta-analyses comparing IA-HA with other nonoperative treatment modalities for knee OA shows that the current highest level of evidence suggests that IA-HA is a viable option for knee OA. Its use results in improvements in knee pain and function that can persist for up to 26 weeks. IA-HA has a good safety profile, and its use should be considered in patients with early knee OA. Level IV, systematic review of Level I to IV studies. Copyright © 2015 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Novel prokaryotic expression of thioredoxin-fused insulinoma associated protein tyrosine phosphatase 2 (IA-2), its characterization and immunodiagnostic application.

PubMed

Guerra, Luciano Lucas; Faccinetti, Natalia Inés; Trabucchi, Aldana; Rovitto, Bruno David; Sabljic, Adriana Victoria; Poskus, Edgardo; Iacono, Ruben Francisco; Valdez, Silvina Noemí

2016-11-24

The insulinoma associated protein tyrosine phosphatase 2 (IA-2) is one of the immunodominant autoantigens involved in the autoimmune attack to the beta-cell in Type 1 Diabetes Mellitus. In this work we have developed a complete and original process for the production and recovery of the properly folded intracellular domain of IA-2 fused to thioredoxin (TrxIA-2 ic ) in Escherichia coli GI698 and GI724 strains. We have also carried out the biochemical and immunochemical characterization of TrxIA-2 ic and design variants of non-radiometric immunoassays for the efficient detection of IA-2 autoantibodies (IA-2A). The main findings can be summarized in the following statements: i) TrxIA-2 ic expression after 3 h of induction on GI724 strain yielded ≈ 10 mg of highly pure TrxIA-2 ic /L of culture medium by a single step purification by affinity chromatography, ii) the molecular weight of TrxIA-2 ic (55,358 Da) could be estimated by SDS-PAGE, size exclusion chromatography and mass spectrometry, iii) TrxIA-2 ic was properly identified by western blot and mass spectrometric analysis of proteolytic digestions (63.25 % total coverage), iv) excellent immunochemical behavior of properly folded full TrxIA-2 ic was legitimized by inhibition or displacement of [ 35 S]IA-2 binding from IA-2A present in Argentinian Type 1 Diabetic patients, v) great stability over time was found under proper storage conditions and vi) low cost and environmentally harmless ELISA methods for IA-2A assessment were developed, with colorimetric or chemiluminescent detection. E. coli GI724 strain emerged as a handy source of recombinant IA-2 ic , achieving high levels of expression as a thioredoxin fusion protein, adequately validated and applicable to the development of innovative and cost-effective immunoassays for IA-2A detection in most laboratories.

Arsenic and ultraviolet radiation exposure: melanoma in a New Mexico non-Hispanic white population.

PubMed

Yager, Janice W; Erdei, Esther; Myers, Orrin; Siegel, Malcolm; Berwick, Marianne

2016-06-01

Cases of cutaneous melanoma and controls were enrolled in a New Mexico population-based study; subjects were administered questionnaires concerning ultraviolet (UV) and inorganic arsenic (iAs) exposure. Historical iAs exposure was estimated. UV exposure estimates were also derived using geospatial methods. Drinking water samples were collected for iAs analysis. Blood samples were collected for DNA repair (Comet) and DNA repair gene polymorphism assays. Arsenic concentrations were determined in urine and toenail samples. UV exposures during the previous 90 days did not vary significantly between cases and controls. Mean (±SD) current home iAs drinking water was not significantly different for cases and controls [3.98 μg/L (±3.67) vs. 3.47 μg/L (±2.40)]. iAs exposure showed no effect on DNA repair or association with melanoma. Results did not corroborate a previously reported association between toenail As and melanoma risk. Arsenic biomarkers in urine and toenail were highly significantly correlated with iAs in drinking water. A UV-DNA repair interaction for UV exposure over the previous 7-90 days was shown; cases had higher DNA damage than controls at low UV values. This novel finding suggests that melanoma cases may be more sensitive to low-level UV exposure than are controls. A UV-APEX1 interaction was shown. Subjects with the homozygous rare APEX1 DNA repair gene allele had a higher risk of early melanoma diagnosis at low UV exposure compared with those with the homozygous wild type or the heterozygote. Notably, a UV-arsenic interaction on inhibition of DNA repair was not observed at iAs drinking water concentrations below 10 ppb (μg/L).

Type Ia supernova host galaxies as seen with IFU spectroscopy

NASA Astrophysics Data System (ADS)

Stanishev, V.; Rodrigues, M.; Mourão, A.; Flores, H.

2012-09-01

Context. Type Ia supernovae (SNe Ia) have been widely used in cosmology as distance indicators. However, to fully exploit their potential in cosmology, a better control over systematic uncertainties is required. Some of the uncertainties are related to the unknown nature of the SN Ia progenitors. Aims: We aim to test the use of integral field unit (IFU) spectroscopy for correlating the properties of nearby SNe Ia with the properties of their host galaxies at the location of the SNe. The results are to be compared with those obtained from an analysis of the total host spectrum. The goal is to explore this path of constraining the nature of the SN Ia progenitors and further improve the use of SNe Ia in cosmology. Methods: We used the wide-field IFU spectrograph PMAS/PPAK at the 3.5 m telescope of Calar Alto Observatory to observe six nearby spiral galaxies that hosted SNe Ia. Spatially resolved 2D maps of the properties of the ionized gas and the stellar populations were derived. Results: Five of the observed galaxies have an ongoing star formation rate of 1-5 M⊙ yr-1 and mean stellar population ages ~5 Gyr. The sixth galaxy shows no star formation and has an about 12 Gyr old stellar population. All galaxies have stellar masses larger than 2 × 1010 M⊙ and metallicities above solar. Four galaxies show negative radial metallicity gradients of the ionized gas up to -0.058 dex kpc-1 and one has nearly uniform metallicity with a possible shallow positive slope. The stellar components show shallower negative metallicity gradients up to -0.03 dex kpc-1. We find no clear correlation between the properties of the galaxy and those of the supernovae, which may be because of the small ranges spanned by the galaxy parameters. However, we note that the Hubble residuals are on average positive while negative Hubble residuals are expected for SNe Ia in massive hosts such as the galaxies in our sample. Conclusions: The IFU spectroscopy on 4-m telescopes is a viable technique for studying host galaxies of nearby SNe Ia. It allows one to correlate the supernova properties with the properties of their host galaxies at the projected positions of the supernovae. Our current sample of six galaxies is too small to draw conclusions about the SN Ia progenitors or correlations with the galaxy properties, but the ongoing CALIFA IFU survey will provide a solid basis to exploit this technique more and improve our understanding of SNe Ia as cosmological standard candles. Based on observations collected at the Centro Astronómico Hispano Alemán (CAHA) at Calar Alto, operated jointly by the Max-Planck Institut für Astronomie and the Instituto de Astrofísica de Andalucía (CSIC).Figures 7-15 and Appendices are available in electronic form at http://www.aanda.org

Global patterns in threats to vertebrates by biological invasions

PubMed Central

Bellard, C.; Genovesi, P.; Jeschke, J. M.

2016-01-01

Biological invasions as drivers of biodiversity loss have recently been challenged. Fundamentally, we must know where species that are threatened by invasive alien species (IAS) live, and the degree to which they are threatened. We report the first study linking 1372 vertebrates threatened by more than 200 IAS from the completely revised Global Invasive Species Database. New maps of the vulnerability of threatened vertebrates to IAS permit assessments of whether IAS have a major influence on biodiversity, and if so, which taxonomic groups are threatened and where they are threatened. We found that centres of IAS-threatened vertebrates are concentrated in the Americas, India, Indonesia, Australia and New Zealand. The areas in which IAS-threatened species are located do not fully match the current hotspots of invasions, or the current hotspots of threatened species. The relative importance of biological invasions as drivers of biodiversity loss clearly varies across regions and taxa, and changes over time, with mammals from India, Indonesia, Australia and Europe are increasingly being threatened by IAS. The chytrid fungus primarily threatens amphibians, whereas invasive mammals primarily threaten other vertebrates. The differences in IAS threats between regions and taxa can help efficiently target IAS, which is essential for achieving the Strategic Plan 2020 of the Convention on Biological Diversity. PMID:26817767

He-accreting carbon-oxygen white dwarfs and Type Ia supernovae

NASA Astrophysics Data System (ADS)

Wang, Bo; Podsiadlowski, Philipp; Han, Zhanwen

2017-12-01

He accretion on to carbon-oxygen white dwarfs (CO WDs) plays a fundamental role when studying the formation of Type Ia supernovae (SNe Ia). Employing the MESA stellar evolution code, we calculated the long-term evolution of He-accreting CO WDs. Previous studies usually supposed that a WD can grow in mass to the Chandrasekhar limit in the stable He burning region and finally produce an SN Ia. However, in this study, we find that off-centre carbon ignition occurs in the stable He burning region if the accretion rate is above a critical value (∼2.05 × 10-6 M⊙ yr-1), resulting in accretion-induced collapse rather than an SN Ia. If the accretion rate is below the critical value, explosive carbon ignition will eventually happen in the centre producing an SN Ia. Taking into account the possibility of off-centre carbon ignition, we have re-determined the initial parameter space that produces SNe Ia in the He star donor channel, one of the promising channels to produce SNe Ia in young populations. Since this parameter space is smaller than was found in the previous study of Wang et al. (2009), the SN Ia rates are also correspondingly smaller. We also determined the chemical abundance profile of the He-accreting WDs at the moment of explosive carbon ignition, which can be used as initial input for SN Ia explosion models.

Dark Energy Survey Group

Science.gov Websites

-Chuan Pan, Companions in Type Ia SNe Remnants 2015-03 Daniel Kasen, Type Ia SNe Models 2014-06 Marisa March, DES Supernovae 2014-06 David Chamulak, Supernova Explosion Models 2011-04 Gene Byrd 2010-04 Liz

Nucleosynthesis of Iron-Peak Elements in Type-Ia Supernovae

NASA Astrophysics Data System (ADS)

Leung, Shing-Chi; Nomoto, Ken'ichi

The observed features of typical Type Ia supernovae are well-modeled as the explosions of carbon-oxygen white dwarfs both near Chandrasekhar mass and sub-Chandrasekhar mass. However, observations in the last decade have shown that Type Ia supernovae exhibit a wide diversity, which implies models for wider range of parameters are necessary. Based on the hydrodynamics code we developed, we carry out a parameter study of Chandrasekhar mass models for Type Ia supernovae. We conduct a series of two-dimensional hydrodynamics simulations of the explosion phase using the turbulent flame model with the deflagration-detonation-transition (DDT). To reconstruct the nucleosynthesis history, we use the particle tracer scheme. We examine the role of model parameters by examining their influences on the final product of nucleosynthesis. The parameters include the initial density, metallicity, initial flame structure, detonation criteria and so on. We show that the observed chemical evolution of galaxies can help constrain these model parameters.

Circulation of Tc Ia discrete type unit Trypanosoma cruzi in Yucatan Mexico.

PubMed

Monteón, Victor; Triana-Chávez, Omar; Mejía-Jaramillo, Ana; Pennignton, Pamela; Ramos-Ligonio, Ángel; Acosta, Karla; Lopez, Ruth

2016-06-01

The etiologic agent Trypanosoma cruzi (Tc) has been grouped into six discrete type units (DTU I-VI); within DTU-I exists four subgroups defined Ia-Id. In Colombia, the genotype Ia is associated with human infection and domiciliated Rhodnius vector. In the Yucatan Peninsula of Mexico, the main vector involved in T. cruzi transmission is Triatoma dimidiata predominantly via sylvatic and peridomiciliated cycles. In this study, multiple sequence analysis of mini-exon intergenic regions of T. cruzi isolates obtained from T. dimidiata in the Yucatan Peninsula of Mexico revealed they belonged to Tc Ia DTU along with two additional Mexican strains located 1,570 km away from Yucatan. In conclusion Tc Ia circulates in the Yucatan peninsula in T. dimidiata vector and likewise in the northwest region of Mexico.

Confronting Alternative Cosmological Models with the Highest-Redshift Type Ia Supernovae

NASA Astrophysics Data System (ADS)

Shafer, Daniel; Scolnic, Daniel; Riess, Adam

2018-01-01

High-redshift Type Ia supernovae (SNe Ia) from the HST CANDELS and CLASH programs significantly extend the Hubble diagram with 7 SNe at z > 1.5 suitable for cosmology, including one at z = 2.3. This unique leverage helps us distinguish "alternative" cosmological models from the standard Lambda-CDM model. Analyzing the Pantheon SN compilation, which includes these high-z SNe, we employ model comparison statistics to quantify the extent to which several proposed alternative expansion histories (e.g., empty universe, power law expansion, timescape cosmology) are disfavored even with SN Ia data alone. Using mock data, we demonstrate that some likelihood analyses used in the literature to support these models are sensitive to unrealistic assumptions and are therefore unsuitable for analysis of realistic SN Ia data.

Clinical, laboratory, and transesophageal echocardiographic correlates of interatrial septal thickness: a population-based transesophageal echocardiographic study.

PubMed

Agmon, Yoram; Meissner, Irene; Tajik, A Jamil; Seward, James B; Petterson, Tanya M; Christianson, Teresa J H; O'Fallon, W Michael; Wiebers, David O; Khandheria, Bijoy K

2005-02-01

The determinants of interatrial septal (IAS) thickening ("lipomatous hypertrophy"), a common echocardiographic finding in the elderly, are poorly defined. The objective of this study was to determine the clinical, laboratory, and transesophageal echocardiographic correlates of IAS thickening in the general population. The thickness of the IAS was measured by transesophageal echocardiography in 384 patients (median age: 66 years; range: 51-101 years; 53% men) participating in a population-based study (Stroke Prevention: Assessment of Risk in a Community). The associations between atherosclerosis risk factors, clinical cardiovascular disease, aortic atherosclerotic plaques, and IAS thickness were examined. Age and body surface area (BSA) were significantly associated with IAS thickness (median: 6 mm; range: 2-17 mm). IAS thickness increased by 12.6% per 10 years of age (95% confidence interval: 9.0-16.4%) adjusting for sex and BSA, and increased by 7.0% per 0.1 m 2 BSA (confidence interval: 5.0-9.2%) adjusting for age and sex. Overall, age, sex, and BSA accounted for 22.5% of the variability in IAS thickness. Current smoking (20.4% increase in IAS thickness in current smokers) and hypertension treatment (8.5% increase in treated patients) were associated with increased IAS thickness, adjusting for age, sex, and BSA ( P < .05), but these two risk factor variables jointly explained only an additional 2.3% of the variability in IAS thickness beyond the variability explained by age, sex, and BSA. Clinical coronary artery and cerebrovascular disease, atrial arrhythmias, and aortic atherosclerotic plaques were not associated with IAS thickness, adjusting for age, sex, and BSA ( P > .3). IAS thickening is an age-associated process. Atherosclerosis risk factors are weakly associated with IAS thickening, whereas atherosclerotic vascular disease is not.

On the relative frequencies of spectroscopically normal and peculiar type Ia supernovae

NASA Technical Reports Server (NTRS)

Branch, David; Fisher, Adam; Nugent, Peter

1993-01-01

After defining what we mean by spectroscopically 'normal' and 'peculiar' Type Ia supernove, we report the results of an attempt to subclassify 84 SNe Ia either as normal or as like one of the recent, peculiar SNe Ia: 1991T, 1991bg, or 1986G. Only SNe 1957A and 1960H are found to have been certifiably abnormal, with SN 1957A; appearing to have been like SN 1991bg, and SN 1960H having been like SN 1991bg or SN 1988G; SNe 1971I and 1980I are under suspicion of having been like SN 1986G, and SN 1988G of having been like SN 1991T. Of the SNe Ia we have been able to classify either as normal or as peculiar, 89% (or 83%, counting those under suspicion as peculiar) are normal. Our main conclusion is that the observational sample of SNe Ia is strongly peaked at 'spectroscopically normal.' We further conclude that when arranged in the photometric sequence of Phillips (1993) SNe Ia also form a spectroscopic sequence, and that peculiar SNe Ia are over-represented in the Phillips sample.

The Influence of Host Galaxies in Type Ia Supernova Cosmology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Uddin, Syed A.; Mould, Jeremy; Lidman, Chris

We use a sample of 1338 spectroscopically confirmed and photometrically classified Type Ia supernovae (SNe Ia) sourced from Carnegie Supernova Project, Center for Astrophysics Supernova Survey, Sloan Digital Sky Survey-II, and SuperNova Legacy Survey SN samples to examine the relationships between SNe Ia and the galaxies that host them. Our results provide confirmation with improved statistical significance that SNe Ia, after standardization, are on average more luminous in massive hosts (significance >5 σ ), and decline more rapidly in massive hosts (significance >9 σ ) and in hosts with low specific star formation rates (significance >8 σ ). We studymore » the variation of these relationships with redshift and detect no evolution. We split SNe Ia into pairs of subsets that are based on the properties of the hosts and fit cosmological models to each subset. Including both systematic and statistical uncertainties, we do not find any significant shift in the best-fit cosmological parameters between the subsets. Among different SN Ia subsets, we find that SNe Ia in hosts with high specific star formation rates have the least intrinsic scatter ( σ {sub int} = 0.08 ± 0.01) in luminosity after standardization.« less

WD+RG systems as the progenitors of type Ia supernovae

NASA Astrophysics Data System (ADS)

Wang, Bo; Han, Zhan-Wen

2010-03-01

Type Ia supernovae (SNe Ia) play an important role in the study of cosmic evolution, especially in cosmology. There are several progenitor models for SNe Ia proposed in the past years. By considering the effect of accretion disk instability on the evolution of white dwarf (WD) binaries, we performed detailed binary evolution calculations for the WD + red-giant (RG) channel of SNe Ia, in which a carbon-oxygen WD accretes material from a RG star to increase its mass to the Chandrasekhar mass limit. According to these calculations, we mapped out the initial and final parameters for SNe Ia in the orbital period-secondary mass (log Pi - Mi2) plane for various WD masses for this channel. We discussed the influence of the variation of the duty cycle value on the regions for producing SNe Ia. Similar to previous studies, this work also indicates that the long-period dwarf novae offer possible ways for producing SNe Ia. Meanwhile, we find that the surviving companion stars from this channel have a low mass after the SN explosion, which may provide a means for the formation of the population of single low-mass WDs (<0.45 Modot).

The Influence of Host Galaxies in Type Ia Supernova Cosmology

NASA Astrophysics Data System (ADS)

Uddin, Syed A.; Mould, Jeremy; Lidman, Chris; Ruhlmann-Kleider, Vanina; Zhang, Bonnie R.

2017-10-01

We use a sample of 1338 spectroscopically confirmed and photometrically classified Type Ia supernovae (SNe Ia) sourced from Carnegie Supernova Project, Center for Astrophysics Supernova Survey, Sloan Digital Sky Survey-II, and SuperNova Legacy Survey SN samples to examine the relationships between SNe Ia and the galaxies that host them. Our results provide confirmation with improved statistical significance that SNe Ia, after standardization, are on average more luminous in massive hosts (significance >5σ), and decline more rapidly in massive hosts (significance >9σ) and in hosts with low specific star formation rates (significance >8σ). We study the variation of these relationships with redshift and detect no evolution. We split SNe Ia into pairs of subsets that are based on the properties of the hosts and fit cosmological models to each subset. Including both systematic and statistical uncertainties, we do not find any significant shift in the best-fit cosmological parameters between the subsets. Among different SN Ia subsets, we find that SNe Ia in hosts with high specific star formation rates have the least intrinsic scatter (σ int = 0.08 ± 0.01) in luminosity after standardization.

HLA-DR4-associated T and B cell responses to specific determinants on the IA-2 autoantigen in type 1 diabetes.

PubMed

McLaughlin, Kerry A; Gulati, Kavita; Richardson, Carolyn C; Morgan, Diana; Bodansky, H Jonathan; Feltbower, Richard G; Christie, Michael R

2014-11-01

Autoantibodies to IA-2 in type 1 diabetes are associated with HLA-DR4, suggesting influences of HLA-DR4-restricted T cells on IA-2-specific B cell responses. The aim of this study was to investigate possible T-B cell collaboration by determining whether autoantibodies to IA-2 epitopes are associated with T cell responses to IA-2 peptides presented by DR4. T cells secreting the cytokines IFN-γ and IL-10 in response to seven peptides known to elicit T cell responses in type 1 diabetes were quantified by cytokine ELISPOT in HLA-typed patients characterized for Abs to IA-2 epitopes. T cell responses were detected to all peptides tested, but only IL-10 responses to 841-860 and 853-872 peptides were associated with DR4. Phenotyping by RT-PCR of FACS-sorted CD45RO(hi) T cells secreting IL-10 in response to these two peptides indicated that these expressed GATA-3 or T-bet, but not FOXP3, consistent with these being Th2 or Th1 memory T cells rather than of regulatory phenotype. T cell responses to the same two peptides were also associated with specific Abs: those to 841-860 peptide with Abs to juxtamembrane epitopes, which appear early in prediabetes, and those to peptide 853-872 with Abs to an epitope located in the 831-862 central region of the IA-2 tyrosine phosphatase domain. Abs to juxtamembrane and central region constructs were both DR4 associated. This study identifies a region of focus for B and T cell responses to IA-2 in HLA-DR4 diabetic patients that may explain HLA associations of IA-2 autoantibodies, and this region may provide a target for future immune intervention to prevent disease. Copyright © 2014 by The American Association of Immunologists, Inc.

The dense core vesicle protein IA-2, but not IA-2β, is required for active avoidance learning.

PubMed

Carmona, G N; Nishimura, T; Schindler, C W; Panlilio, L V; Notkins, A L

2014-06-06

The islet-antigens IA-2 and IA-2β are major autoantigens in type-1 diabetes and transmembrane proteins in dense core vesicles (DCV). Recently we showed that deletion of both IA-2 and IA-2β alters the secretion of hormones and neurotransmitters and impairs behavior and learning. The present study was designed to evaluate the contribution to learning of each of these genes by using single knockout (SKO) and double knockout (DKO) mice in an active avoidance test. After 5 days of training, wild-type (WT) mice showed 60-70% active avoidance responses, whereas the DKO mice showed only 10-15% active avoidance responses. The degree of active avoidance responses in the IA-2 SKO mice was similar to that of the DKO mice, but in contrast, the IA-2β SKO mice behaved like WT mice showing 60-70% active avoidance responses. Molecular studies revealed a marked decrease in the phosphorylation of the cAMP response element-binding protein (CREB) and Ca(2+)/calmodulin-dependent protein kinase II (CAMKII) in the striatum and hippocampus of the IA-2 SKO and DKO mice, but not in the IA-2β SKO mice. To evaluate the role of CREB and CAMKII in the SKO and DKO mice, GBR-12909, which selectively blocks the dopamine uptake transporter and increases CREB and CAMKII phosphorylation, was administered. GBR-12909 restored the phosphorylation of CREB and CAMKII and increased active avoidance learning in the DKO and IA-2 SKO to near the normal levels found in the WT and IA-2β SKO mice. We conclude that in the absence of the DCV protein IA-2, active avoidance learning is impaired. Published by Elsevier Ltd.

Spectrum synthesis of the Type Ia supernovae SN 1992A and SN 1981B

NASA Technical Reports Server (NTRS)

Nugent, Peter; Baron, E.; Hauschildt, Peter H.; Branch, David

1995-01-01

We present non-local thermodynamic equilibrium (non-LTE) synthetic spectra for the Type Ia supernovae SN 1992A and SN 1981B, near maximum light. At this epoch both supernovae were observed from the UV through the optical. This wide spectral coverage is essential for determining the density structure of a SN Ia. Our fits are in good agreement with observation and provide some insight as to the differences between these supernovae. We also discuss the application of the expanding photosphere method to SNe Ia which gives a distance that is independent of those based on the decay of Ni-56 and Cepheid variable stars.

Follow-up Findings in a Turkish Girl with Pseudohypoparathyroidism Type Ia Caused by a Novel Heterozygous Mutation in the GNAS Gene.

PubMed

Şahin, Sezgin; Hiort, Olaf; Thiele, Susanne; Evliyaoğlu, Olcay; Tüysüz, Beyhan

2017-03-01

Pseudohypoparathyroidism type Ia (PHP-Ia) is characterized by multihormone resistance and an Albright hereditary osteodystrophy (AHO) phenotype. It is caused by heterozygous mutations in GNAS gene. Clinical and biochemical findings of a female PHP-Ia patient were evaluated from age of diagnosis (6.5 years) to 14.5 years of age. The patient had short stature, brachydactyly, and subcutaneous heterotopic ossifications. Serum calcium and phosphorus levels were normal, but parathyroid hormone levels were high. Based on the typical clinical findings of AHO phenotype and biochemical findings, she was diagnosed as having PHP-Ia. A novel heterozygous mutation (c.128T>C) was found in the GNAS gene. Follow-up examinations revealed resistance to thyroid-stimulating hormone and a bioinactive growth hormone. Clinicians should take into consideration PHP-Ia in patients referred with short stature, and patients with an AHO phenotype must be further evaluated for hormone resistance, GNAS gene mutation, Gsα activity. To our knowledge, this is the first case report describing bioinactive growth hormone in PHP-Ia.

Why Are Peculiar Type Ia Supernovae More Likely to Show the Signature of a Single-degenerate Model?

NASA Astrophysics Data System (ADS)

Meng, Xiang-Cun; Han, Zhan-Wen

2018-03-01

Although type Ia supernovae (SNe Ia) are very useful in many astrophysical fields, their exact progenitor nature is still unclear. A basic method to distinguish the different progenitor models is to search the signal from the single-degenerate (SD) model, e.g., the signal for the existence of a nondegenerate companion before or after supernova explosion. Observationally, some SNe Ia show such signals, while the others do not. Here, we propose a universal model to explain these observations based on the spin-up/spin-down model, in which a white dwarf (WD) will experience a spin-down phase before supernova explosion, and the spin-down timescale is determined by its initial mass, i.e., the more massive the initial WD, the shorter the spin-down timescale and then the more likely the SN Ia is to show the SD signature. Therefore, our model predicts that the SNe Ia from hybrid carbon–oxygen–neon WDs are more likely to show the SD signature observationally, as some peculiar SNe Ia showed.

Very-high-energy gamma-ray observations of the Type Ia Supernova SN 2014J with the MAGIC telescopes

NASA Astrophysics Data System (ADS)

Ahnen, M. L.; Ansoldi, S.; Antonelli, L. A.; Antoranz, P.; Arcaro, C.; Babic, A.; Banerjee, B.; Bangale, P.; Barres de Almeida, U.; Barrio, J. A.; Becerra González, J.; Bednarek, W.; Bernardini, E.; Berti, A.; Biasuzzi, B.; Biland, A.; Blanch, O.; Bonnefoy, S.; Bonnoli, G.; Borracci, F.; Bretz, T.; Carosi, R.; Carosi, A.; Chatterjee, A.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; Cumani, P.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Lotto, B.; de Oña Wilhelmi, E.; Di Pierro, F.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Einecke, S.; Eisenacher Glawion, D.; Elsaesser, D.; Engelkemeier, M.; Fallah Ramazani, V.; Fernández-Barral, A.; Fidalgo, D.; Fonseca, M. V.; Font, L.; Frantzen, K.; Fruck, C.; Galindo, D.; García López, R. J.; Garczarczyk, M.; Garrido Terrats, D.; Gaug, M.; Giammaria, P.; Godinović, N.; Gora, D.; Guberman, D.; Hadasch, D.; Hahn, A.; Hayashida, M.; Herrera, J.; Hose, J.; Hrupec, D.; Hughes, G.; Idec, W.; Kodani, K.; Konno, Y.; Kubo, H.; Kushida, J.; La Barbera, A.; Lelas, D.; Lindfors, E.; Lombardi, S.; Longo, F.; López, M.; López-Coto, R.; Majumdar, P.; Makariev, M.; Mallot, K.; Maneva, G.; Manganaro, M.; Mannheim, K.; Maraschi, L.; Marcote, B.; Mariotti, M.; Martínez, M.; Mazin, D.; Menzel, U.; Miranda, J. M.; Mirzoyan, R.; Moralejo, A.; Moretti, E.; Nakajima, D.; Neustroev, V.; Niedzwiecki, A.; Nievas Rosillo, M.; Nilsson, K.; Nishijima, K.; Noda, K.; Nogués, L.; Paiano, S.; Palacio, J.; Palatiello, M.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Paredes-Fortuny, X.; Pedaletti, G.; Peresano, M.; Perri, L.; Persic, M.; Poutanen, J.; Prada Moroni, P. G.; Prandini, E.; Puljak, I.; Garcia, J. R.; Reichardt, I.; Rhode, W.; Ribó, M.; Rico, J.; Saito, T.; Satalecka, K.; Schroeder, S.; Schweizer, T.; Sillanpää, A.; Sitarek, J.; Snidaric, I.; Sobczynska, D.; Stamerra, A.; Strzys, M.; Surić, T.; Takalo, L.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Torres, D. F.; Toyama, T.; Treves, A.; Vanzo, G.; Vazquez Acosta, M.; Vovk, I.; Ward, J. E.; Will, M.; Wu, M. H.; Zanin, R.

2017-06-01

Context. In this work we present data from observations with the MAGIC telescopes of SN 2014J detected on January 21 2014, the closest Type Ia supernova since Imaging Air Cherenkov Telescopes started to operate. Aims: We aim to probe the possibility of very-high-energy (VHE; E ≥ 100 GeV) gamma rays produced in the early stages of Type Ia supernova explosions. Methods: We performed follow-up observations after this supernova (SN) explosion for five days, between January 27 and February 2 2014. We searched for gamma-ray signals in the energy range between 100 GeV and several TeV from the location of SN 2014J using data from a total of 5.5 h of observations. Prospects for observing gamma rays of hadronic origin from SN 2014J in the near future are also being addressed. Results: No significant excess was detected from the direction of SN 2014J. Upper limits at 95% confidence level on the integral flux, assuming a power-law spectrum, dF/dE ∝ E- Γ, with a spectral index of Γ = 2.6, for energies higher than 300 GeV and 700 GeV, are established at 1.3 × 10-12 and 4.1 × 10-13 photons cm-2 s-1, respectively. Conclusions: For the first time, upper limits on the VHE emission of a Type Ia supernova are established. The energy fraction isotropically emitted into TeV gamma rays during the first 10 days after the supernova explosion for energies greater than 300 GeV is limited to 10-6 of the total available energy budget ( 1051 erg). Within the assumed theoretical scenario, the MAGIC upper limits on the VHE emission suggest that SN 2014J will not be detectable in the future by any current or planned generation of Imaging Atmospheric Cherenkov Telescopes.

The effect of background galaxy contamination on the absolute magnitude and light curve speed class of type Ia supernovae

NASA Technical Reports Server (NTRS)

Boisseau, John R.; Wheeler, J. Craig

1991-01-01

Observational data are presented in support of the hypothesis that background galaxy contamination is present in the photometric data of Ia supernovae and that this effect can account for the observed dispersion in the light curve speeds of most of Ia supernovae. The implication is that the observed dispersion in beta is artificial and that most of Ia supernovae have nearly homogeneous light curves. The result supports the notion that Ia supernovae are good standard candles.

Impact of anti-insulin antibodies on islet transplantation outcome: data from the GRAGIL Network.

PubMed

Lablanche, Sandrine; Borot, Sophie; Thaunat, Olivier; Bayle, Francois; Badet, Lionel; Morelon, Emmanuel; Thivolet, Charles; Wojtusciszyn, Anne; Frimat, Luc; Kessler, Laurence; Penfornis, Alfred; Brault, Coralie; Colin, Cyrille; Bosco, Domenico; Berney, Thierry; Benhamou, Pierre Y

2014-08-27

In patients with type 1 diabetes, insulin antibodies (IA), altering the pharmacokinetics of circulating insulin, might be associated with high glucose concentration, prolonged hypoglycemia, and higher insulin requirement. The impact of IA on islet transplantation has never been explored. Our aim was to evaluate islet transplantation results at 1 year according to the presence of IA. Our work is a retrospective, case-control study, comparing IA-negative and IA-positive patients among the cohort of patients with type 1 diabetes transplanted within the Swiss-French GRAGIL network between 2003 and 2010. Data about IA were available for 17 patients. Before islet transplantation, 10 patients (59%) were screened positive for IA. At 12 months after transplantation, IA-positive patients reached insulin independence less frequently than IA-negative patients (cumulative incidence of insulin independence, 22.2% vs. 71.4%; P=0.02); β score was ≥7 in 43% of IA-negative patients versus 0% in IA-positive patients (P=0.022). When comparing IA-positive patients with IA-negative patients, insulin dose was 0.15 U/kg (0.10-0.18 U/kg) versus 0.01 U/kg (0-0.09 U/kg) (P=0.2); HbA1c was 6.1% (5.8%-6.3%) versus 6.1% (5.9%-6.8%) (P=0.16); basal C-peptide level was 460 ρmol/L (350-510 ρmol/L) versus 265 ρmol/L (177-405 ρmol/L) (P=0.28); occurrence of hypoglycemia was 12.5% versus 16.5% (P=0.9); and homeostatic model assessment insulin resistance was 1.25 (1-2.4) versus 0.7 (0.52-0.92) (P=0.01). After islet transplantation, IA-positive patients achieved insulin independence less frequently, exhibiting lower β score and higher homeostatic model assessment insulin resistance compared with IA-negative patients. However, in both groups, islet transplantation restored good glycemic control and drastically reduced hypoglycemia and insulin requirements.

The auxiliary subunit KChIP2 is an essential regulator of homeostatic excitability.

PubMed

Wang, Hong-Gang; He, Xiao Ping; Li, Qiang; Madison, Roger D; Moore, Scott D; McNamara, James O; Pitt, Geoffrey S

2013-05-10

The necessity for, or redundancy of, distinctive KChIP proteins is not known. Deletion of KChIP2 leads to increased susceptibility to epilepsy and to a reduction in IA and increased excitability in pyramidal hippocampal neurons. KChIP2 is essential for homeostasis in hippocampal neurons. Mutations in K(A) channel auxiliary subunits may be loci for epilepsy. The somatodendritic IA (A-type) K(+) current underlies neuronal excitability, and loss of IA has been associated with the development of epilepsy. Whether any one of the four auxiliary potassium channel interacting proteins (KChIPs), KChIP1-KChIP4, in specific neuronal populations is critical for IA is not known. Here we show that KChIP2, which is abundantly expressed in hippocampal pyramidal cells, is essential for IA regulation in hippocampal neurons and that deletion of Kchip2 affects susceptibility to limbic seizures. The specific effects of Kchip2 deletion on IA recorded from isolated hippocampal pyramidal neurons were a reduction in amplitude and shift in the V½ for steady-state inactivation to hyperpolarized potentials when compared with WT neurons. Consistent with the relative loss of IA, hippocampal neurons from Kchip2(-/-) mice showed increased excitability. WT cultured neurons fired only occasional single action potentials, but the average spontaneous firing rate (spikes/s) was almost 10-fold greater in Kchip2(-/-) neurons. In slice preparations, spontaneous firing was detected in CA1 pyramidal neurons from Kchip2(-/-) mice but not from WT. Additionally, when seizures were induced by kindling, the number of stimulations required to evoke an initial class 4 or 5 seizure was decreased, and the average duration of electrographic seizures was longer in Kchip2(-/-) mice compared with WT controls. Together, these data demonstrate that the KChIP2 is essential for physiologic IA modulation and homeostatic stability and that there is a lack of functional redundancy among the different KChIPs in hippocampal neurons.

An Alternative Approach for Treating a Type Ia Endoleak after Conventional EVAR Using the Nellix Endovascular Aneurysm Sealing.

PubMed

Martinelli, Ombretta; Fresilli, Mauro; Irace, Luigi; Venosi, Salvatore; Jabbour, Jihad; Picone, Veronica; Maruca, Debora; Di Girolamo, Alessia; Gossetti, Bruno

2018-05-01

To report the use of a Nellix endovascular aneurysm sealing (EVAS) device, to successfully treat a type Ia endoleak (EL) after an endovascular aortic repair (EVAR). A 70-year-old man was diagnosed with a 90-mm aortic aneurysm, suspicious for being inflammatory. It was initially treated successfully, with a Medtronic Endurant (Medtronic, Minneapolis, MN, USA). Five years after the index endovascular repair, an asymptomatic type Ia EL was detected on duplex ultrasound and computed tomographic angiogram. Other endovascular solutions in the form of proximal cuff, chimney was considered difficult to execute due to challenges in planning, manipulation, and renal cannulation caused by the short proximal sealing zone above the existing stent graft and the constraints of the previous endograft. Thus, a relining of the previous endoprothesis was performed using the Nellix system (Endologix, Inc., Irvine, CA, USA). One-year follow-up imaging demonstrated successful resolution of the EL and persistent sealing of the Nellix device. Nellix EVAS system can be an alternative and safe option for relining a stent graft with a type Ia EL. Nellix platform can be added to the clinician's armamentarium for treating type Ia EL after conventional EVAR of infrarenal abdominal aortic aneurysm (AAA). Copyright © 2018 Elsevier Inc. All rights reserved.

The type Ia supernova SNLS-03D3bb from a super-Chandrasekhar-mass white dwarf star.

PubMed

Howell, D Andrew; Sullivan, Mark; Nugent, Peter E; Ellis, Richard S; Conley, Alexander J; Le Borgne, Damien; Carlberg, Raymond G; Guy, Julien; Balam, David; Basa, Stephane; Fouchez, Dominique; Hook, Isobel M; Hsiao, Eric Y; Neill, James D; Pain, Reynald; Perrett, Kathryn M; Pritchet, Christopher J

2006-09-21

The accelerating expansion of the Universe, and the need for dark energy, were inferred from observations of type Ia supernovae. There is a consensus that type Ia supernovae are thermonuclear explosions that destroy carbon-oxygen white dwarf stars that have accreted matter from a companion star, although the nature of this companion remains uncertain. These supernovae are thought to be reliable distance indicators because they have a standard amount of fuel and a uniform trigger: they are predicted to explode when the mass of the white dwarf nears the Chandrasekhar mass of 1.4 solar masses (M(o)). Here we show that the high-redshift supernova SNLS-03D3bb has an exceptionally high luminosity and low kinetic energy that both imply a super-Chandrasekhar-mass progenitor. Super-Chandrasekhar-mass supernovae should occur preferentially in a young stellar population, so this may provide an explanation for the observed trend that overluminous type Ia supernovae occur only in 'young' environments. As this supernova does not obey the relations that allow type Ia supernovae to be calibrated as standard candles, and as no counterparts have been found at low redshift, future cosmology studies will have to consider possible contamination from such events.

Lipid management among individuals with inflammatory arthritis in the national REasons for Geographic And Racial Differences in Stroke (REGARDS) cohort.

PubMed

Navarro-Millán, Iris; Gamboa, Christopher M; Curtis, Jeffrey R; Safford, Monika M

2018-01-01

Objective Hyperlipidemia guidelines do not currently identify inflammatory arthritis (IA) as a cardiovascular disease (CVD) risk factor. We compared hyperlipidemia treatment of individuals with and without IA (rheumatoid arthritis, psoriatic arthritis, or ankylosing spondylitis) in a large national cohort. Methods Participants from the REasons for Geographic And Racial Differences in Stroke (REGARDS) study were classified as having IA (without diabetes or hypertension); diabetes (but no IA); hypertension (but no diabetes or IA); or no IA, diabetes, or hypertension. Multivariable logistic regression models examined the odds of medical treatment among those with hyperlipidemia. Results Thirty-nine participants had IA, 5423 had diabetes, 7534 had hypertension, and 5288 had no diabetes, hypertension, or IA. The fully adjusted odds of treatment were similar between participants with IA and those without IA, hypertension, or diabetes. Participants with diabetes and no IA and participants with hypertension and no IA were twice as likely to be treated for hyperlipidemia as those without IA, diabetes, or hypertension. Conclusion Despite their higher CVD risk, patients with IA were as likely to be treated for hyperlipidemia as those without diabetes, hypertension, or IA. Lipid guidelines should identify IA as a CVD risk factor to improve CVD risk optimization in IA.

Evidence for Ni-56 yields Co-56 yields Fe-56 decay in type Ia supernovae

NASA Technical Reports Server (NTRS)

Kuchner, Marc J.; Kirshner, Robert P.; Pinto, Philip A.; Leibundgut, Bruno

1994-01-01

In the prevailing picture of Type Ia supernovae (SN Ia), their explosive burning produces Ni-56, and the radioactive decay chain Ni-56 yields Co-56 yields Fe-56 powers the subsequent emission. We test a central feature of this theory by measuring the relative strengths of a (Co III) emission feature near 5900 A and a (Fe III) emission feature near 4700 A. We measure 38 spectra from 13 SN Ia ranging from 48 to 310 days after maximum light. When we compare the observations with a simple multilevel calculation, we find that the observed Fe/Co flux ratio evolves as expected when the Fe-56/Co-56 abundance ratio follows from Ni-56 yields Co-56 yields Fe-56 decay. From this agreement, we conclude that the cobalt and iron atoms we observe through SN Ia emission lines are produced by the radioactive decay of Ni-56, just as predicted by a wide range of models for SN Ia explosions.

Testing cosmic transparency with the latest baryon acoustic oscillations and type Ia supernovae data

NASA Astrophysics Data System (ADS)

Chen, Jun; Wu, Pu-Xun; Yu, Hong-Wei; Li, Zheng-Xiang

2013-06-01

Observations show that Type Ia supernovae (SNe Ia) are dimmer than expected from a matter dominated Universe. It has been suggested that this observed phenomenon can also be explained using light absorption instead of dark energy. However, there is a serious degeneracy between the cosmic absorption parameter and the present matter density parameter Ωm when one tries to place constraints on the cosmic opacity using SNe Ia data. We combine the latest baryon acoustic oscillation (BAO) and Union2 SNe Ia data in order to break this degeneracy. Assuming a flat ΛCDM model, we find that, although an opaque Universe is favored by SNe Ia+BAO since the best fit value of the cosmic absorption parameter is larger than zero, Ωm = 1 is ruled out at the 99.7% confidence level. Thus, cosmic opacity is not sufficient to account for the present observations and dark energy or modified gravity is still required.

Testing averaged cosmology with type Ia supernovae and BAO data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Santos, B.; Alcaniz, J.S.; Coley, A.A.

An important problem in precision cosmology is the determination of the effects of averaging and backreaction on observational predictions, particularly in view of the wealth of new observational data and improved statistical techniques. In this paper, we discuss the observational viability of a class of averaged cosmologies which consist of a simple parametrized phenomenological two-scale backreaction model with decoupled spatial curvature parameters. We perform a Bayesian model selection analysis and find that this class of averaged phenomenological cosmological models is favored with respect to the standard ΛCDM cosmological scenario when a joint analysis of current SNe Ia and BAO datamore » is performed. In particular, the analysis provides observational evidence for non-trivial spatial curvature.« less

Type Ia Supernova Distances at Redshift >1.5 from the Hubble Space Telescope Multi-cycle Treasury Programs: The Early Expansion Rate

NASA Astrophysics Data System (ADS)

Riess, Adam G.; Rodney, Steven A.; Scolnic, Daniel M.; Shafer, Daniel L.; Strolger, Louis-Gregory; Ferguson, Henry C.; Postman, Marc; Graur, Or; Maoz, Dan; Jha, Saurabh W.; Mobasher, Bahram; Casertano, Stefano; Hayden, Brian; Molino, Alberto; Hjorth, Jens; Garnavich, Peter M.; Jones, David O.; Kirshner, Robert P.; Koekemoer, Anton M.; Grogin, Norman A.; Brammer, Gabriel; Hemmati, Shoubaneh; Dickinson, Mark; Challis, Peter M.; Wolff, Schuyler; Clubb, Kelsey I.; Filippenko, Alexei V.; Nayyeri, Hooshang; U, Vivian; Koo, David C.; Faber, Sandra M.; Kocevski, Dale; Bradley, Larry; Coe, Dan

2018-02-01

We present an analysis of 15 Type Ia supernovae (SNe Ia) at redshift z> 1 (9 at 1.5< z< 2.3) recently discovered in the CANDELS and CLASH Multi-Cycle Treasury programs using WFC3 on the Hubble Space Telescope. We combine these SNe Ia with a new compilation of ∼1050 SNe Ia, jointly calibrated and corrected for simulated survey biases to produce accurate distance measurements. We present unbiased constraints on the expansion rate at six redshifts in the range 0.07< z< 1.5 based only on this combined SN Ia sample. The added leverage of our new sample at z> 1.5 leads to a factor of ∼3 improvement in the determination of the expansion rate at z = 1.5, reducing its uncertainty to ∼20%, a measurement of H(z=1.5)/{H}0 = {2.69}-0.52+0.86. We then demonstrate that these six derived expansion rate measurements alone provide a nearly identical characterization of dark energy as the full SN sample, making them an efficient compression of the SN Ia data. The new sample of SNe Ia at z> 1.5 usefully distinguishes between alternative cosmological models and unmodeled evolution of the SN Ia distance indicators, placing empirical limits on the latter. Finally, employing a realistic simulation of a potential Wide-Field Infrared Survey Telescope SN survey observing strategy, we forecast optimistic future constraints on the expansion rate from SNe Ia.

Extending Supernova Spectral Templates for Next Generation Space Telescope Observations

NASA Astrophysics Data System (ADS)

Roberts-Pierel, Justin; Rodney, Steven A.; Steven Rodney

2018-01-01

Widely used empirical supernova (SN) Spectral Energy Distributions (SEDs) have not historically extended meaningfully into the ultraviolet (UV), or the infrared (IR). However, both are critical for current and future aspects of SN research including UV spectra as probes of poorly understood SN Ia physical properties, and expanding our view of the universe with high-redshift James Webb Space Telescope (JWST) IR observations. We therefore present a comprehensive set of SN SED templates that have been extended into the UV and IR, as well as an open-source software package written in Python that enables a user to generate their own extrapolated SEDs. We have taken a sampling of core-collapse (CC) and Type Ia SNe to get a time-dependent distribution of UV and IR colors (U-B,r’-[JHK]), and then generated color curves are used to extrapolate SEDs into the UV and IR. The SED extrapolation process is now easily duplicated using a user’s own data and parameters via our open-source Python package: SNSEDextend. This work develops the tools necessary to explore the JWST’s ability to discriminate between CC and Type Ia SNe, as well as provides a repository of SN SEDs that will be invaluable to future JWST and WFIRST SN studies.

Supernova Ia Spectra and Spectrophotometric Time Series: Recognizing Twins and the Consequences for Cosmological Distance Measurements

NASA Astrophysics Data System (ADS)

Fakhouri, Hannah Kathleen

In Part I we introduce the method and results of the Twin Supernova analysis. This novel approach to Type Ia supernova standardization is currently only possible with spectrophotometric timeseries observations from the Nearby Supernova Factory. As Chapters 1 through 4 will explore, we select an ideal subset of supernovae, find pairs whose features match well in flux at all wavelengths and times, and test their dispersion in brightness. The analysis is completed in a blinded fashion, ensuring that we are not tuning our results. What we find is that twin supernovae do indeed have a small brightness dispersion. Part II shows two additional analyses related to the standardization of Type Ia supernovae. In Chapter 5 we present a check on the results of Bailey et al. [2009]. Literature supernovae with spectra near maximum light were tested to see how well their magnitudes could be standardized using the flux ratio method of Bailey et al [2009]. Chapter 6 shows a study with data from the Nearby Supernova Factory. Using only the spectrophotometric observations near maximum light, we calculate monochromatic Hubble Diagram residuals for each supernova. Those residuals are then corrected using a flux ratio, similar to Bailey et al. [2009] to test the standardization possibilities using only near-maximum observations.

Perception of autonomy and connectedness prior to the onset of anorexia nervosa and bulimia nervosa.

PubMed

Huemer, Julia; Haidvogl, Maria; Mattejat, Fritz; Wagner, Gudrun; Nobis, Gerald; Fernandez-Aranda, Fernando; Collier, David A; Treasure, Janet L; Karwautz, Andreas F K

2012-01-01

This study examines retrospective correlates of nonshared family environment prior to onset of disease, by means of multiple familial informants, among anorexia and bulimia nervosa patients. A total of 332 participants was included (anorexia nervosa, restrictive type (AN-R): n = 41 plus families); bulimic patients (anorexia nervosa, binge-purging type; bulimia nervosa: n = 59 plus families). The EATAET Lifetime Diagnostic Interview was used to establish the diagnosis; the Subjective Family Image Test was used to derive emotional connectedness (EC) and individual autonomy (IA). Bulimic and AN-R patients perceived significantly lower EC prior to onset of disease compared to their healthy sisters. Bulimic patients perceived significantly lower EC prior to onset of disease compared to AN-R patients and compared to their mothers and fathers. A low family sum - sister pairs sum comparison - of EC had a significant influence on the risk of developing bulimia nervosa. Contrary to expectations, AN-R patients did not perceive significantly lower levels of IA compared to their sisters, prior to onset of disease. Findings of low IA in currently ill AN-R patients may represent a disease consequence, not a risk factor. Developmental child psychiatrists should direct their attention to disturbances of EC, which may be present prior to the onset of the disease.

The use of biomarkers and molecular methods for the earlier diagnosis of invasive aspergillosis in immunocompromised patients.

PubMed

Ambasta, Anshula; Carson, Julie; Church, Deirdre L

2015-08-01

Invasive aspergillosis (IA) is an opportunistic infection that is often life threatening in the immunocompromised host. Early diagnosis is critical, especially given the efficacy and availability of several new anti-fungal therapies. Current (2008) diagnostic criteria have limited ability to detect early infection and are aimed at establishing disease. Although histopathology and culture techniques have traditionally been used to make a proven diagnosis of IA, their dependence on tissue samples and slow turnaround times hamper early confirmation of IA. Serologic detection of circulating galactomannan and 1,3-β-D-glucan fungal biomarkers show promise for improving the diagnosis of IA, and their use is included in the EORTC/MSG diagnostic criteria for IA. Numerous studies have evaluated the diagnostic performance of these two biomarkers and shown that they have suboptimal sensitivity when used alone for early diagnosis of proven IA. Currently available molecular assays also suffer from a lack of standardization. Evaluation of the use of different combinations of test methods to enhance diagnostic accuracy is also being done but prompt, accurate diagnosis of IA remains a clinical and diagnostic challenge. The clinical validity and limitations of biomarkers and current molecular methods for the early diagnosis of IA are summarized in this review with respect to the different patient populations at risk for this serious infection. © The Author 2015. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Distance Probes of Dark Energy

DOE PAGES

Kim, A. G.; Padmanabhan, N.; Aldering, G.; ...

2015-03-15

We present the results from the Distances subgroup of the Cosmic Frontier Community Planning Study (Snowmass 2013). This document summarizes the current state of the field as well as future prospects and challenges. In addition to the established probes using Type Ia supernovae and baryon acoustic oscillations, we also consider prospective methods based on clusters, active galactic nuclei, gravitational wave sirens and strong lensing time delays.

Type Ia Supernova Rate Measurements to Redshift 2.5 from Candles: Searching for Prompt Explosions in the Early Universe

NASA Technical Reports Server (NTRS)

Rodney, Steven A.; Riess, Adam G.; Strogler, Louis-Gregory; Dahlen, Tomas; Graur, Or; Casertano, Stefano; Dickinson, Mark E.; Ferguson, Henry C.; Garnavich, Peter; Cenko, Stephen Bradley

2014-01-01

The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) was a multi-cycle treasury program on the Hubble Space Telescope(HST) that surveyed a total area of approx. 0.25 deg(sup 2) with approx.900 HST orbits spread across five fields over three years. Within these survey images we discovered 65 supernovae (SNe) of all types, out to z approx. 2.5. We classify approx. 24 of these as Type Ia SNe (SNe Ia) based on host galaxy redshifts and SN photometry (supplemented by grism spectroscopy of six SNe). Here we present a measurement of the volumetric SN Ia rate as a function of redshift, reaching for the first time beyond z = 2 and putting new constraints on SN Ia progenitor models. Our highest redshift bin includes detections of SNe that exploded when the universe was only approx. 3 Gyr old and near the peak of the cosmic star formation history. This gives the CANDELS high redshift sample unique leverage for evaluating the fraction of SNe Ia that explode promptly after formation (500 Myr). Combining the CANDELS rates with all available SN Ia rate measurements in the literature we find that this prompt SN Ia fraction isfP0.530.09stat0.100.10sys0.26, consistent with a delay time distribution that follows a simplet1power law for all timest40 Myr. However, mild tension is apparent between ground-based low-z surveys and space-based high-z surveys. In both CANDELS and the sister HST program CLASH (Cluster Lensing And Supernova Survey with Hubble), we find a low rate of SNe Ia at z > 1. This could be a hint that prompt progenitors are in fact relatively rare, accounting for only 20 of all SN Ia explosions though further analysis and larger samples will be needed to examine that suggestion.

Multilocus Sequence Typing of an Emerging Cryptosporidium hominis Subtype in the United States

PubMed Central

Tiao, Narry; Li, Na; Hlavsa, Michele

2014-01-01

The United States has experienced a substantial increase in the reported incidence of cryptosporidiosis since 2005. Accompanying this is the emergence of a new subtype of Cryptosporidium hominis based on variation at the 60-kDa glycoprotein (gp60) locus, IaA28R4, which has become a frequently identified subtype in both sporadic and outbreak-related cases. In this study, using multilocus sequence typing (MLST) at eight genetic loci, we characterized 62 specimens of IaA28R4 and 33 specimens of three other gp60 subtypes of C. hominis from four U.S. states with increased cryptosporidiosis incidences during the summer of 2008. Extensive genetic heterogeneity was seen within the gp60 subtype IaA28R4, but specimens from Ohio and southwestern states formed two distinct subpopulations, suggesting that there were at least two origins of IaA28R4 within the United States. Discordance in typing results was observed between gp60 and other genetic markers, especially DZ-HRGP, and this discordance was largely the result of genetic recombination within the gp60 subtype IaA28R4. The results of population genetic analyses supported the presence of two subpopulations of IaA28R4 and the occurrence of genetic recombination within this gp60 subtype. Thus, the IaA28R4 subtype at gp60 is likely a fitness marker for C. hominis, and genetic recombination is potentially a driving force in the emergence of the virulent IaA28R4 subtype in the United States. A rapid evolution of IaA28R4 was indicated by the observation of multiple MLST subtypes of IaA28R4 within two large outbreaks that lasted for extended periods and involved multiple swimming pools. PMID:24478483

Type Ia Supernova Rate Measurements to Redshift 2.5 from CANDELS: Searching for Prompt Explosions in the Early Universe

NASA Astrophysics Data System (ADS)

Rodney, Steven A.; Riess, Adam G.; Strolger, Louis-Gregory; Dahlen, Tomas; Graur, Or; Casertano, Stefano; Dickinson, Mark E.; Ferguson, Henry C.; Garnavich, Peter; Hayden, Brian; Jha, Saurabh W.; Jones, David O.; Kirshner, Robert P.; Koekemoer, Anton M.; McCully, Curtis; Mobasher, Bahram; Patel, Brandon; Weiner, Benjamin J.; Cenko, S. Bradley; Clubb, Kelsey I.; Cooper, Michael; Filippenko, Alexei V.; Frederiksen, Teddy F.; Hjorth, Jens; Leibundgut, Bruno; Matheson, Thomas; Nayyeri, Hooshang; Penner, Kyle; Trump, Jonathan; Silverman, Jeffrey M.; U, Vivian; Azalee Bostroem, K.; Challis, Peter; Rajan, Abhijith; Wolff, Schuyler; Faber, S. M.; Grogin, Norman A.; Kocevski, Dale

2014-07-01

The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) was a multi-cycle treasury program on the Hubble Space Telescope (HST) that surveyed a total area of ~0.25 deg2 with ~900 HST orbits spread across five fields over three years. Within these survey images we discovered 65 supernovae (SNe) of all types, out to z ~ 2.5. We classify ~24 of these as Type Ia SNe (SNe Ia) based on host galaxy redshifts and SN photometry (supplemented by grism spectroscopy of six SNe). Here we present a measurement of the volumetric SN Ia rate as a function of redshift, reaching for the first time beyond z = 2 and putting new constraints on SN Ia progenitor models. Our highest redshift bin includes detections of SNe that exploded when the universe was only ~3 Gyr old and near the peak of the cosmic star formation history. This gives the CANDELS high redshift sample unique leverage for evaluating the fraction of SNe Ia that explode promptly after formation (<500 Myr). Combining the CANDELS rates with all available SN Ia rate measurements in the literature we find that this prompt SN Ia fraction is f_{P}\\,{=}\\,0.53^{\\ \\,\\, +/- 0.09}_{stat0.10} {}^{\\ \\, +/- 0.10}_{sys 0.26}, consistent with a delay time distribution that follows a simple t -1 power law for all times t > 40 Myr. However, mild tension is apparent between ground-based low-z surveys and space-based high-z surveys. In both CANDELS and the sister HST program CLASH (Cluster Lensing And Supernova Survey with Hubble), we find a low rate of SNe Ia at z > 1. This could be a hint that prompt progenitors are in fact relatively rare, accounting for only 20% of all SN Ia explosions—though further analysis and larger samples will be needed to examine that suggestion.

Genotypic evaluation of etravirine sensitivity of clinical human immunodeficiency virus type 1 (HIV-1) isolates carrying resistance mutations to nevirapine and efavirenz.

PubMed

Oumar, A A; Jnaoui, K; Kabamba-Mukadi, B; Yombi, J C; Vandercam, B; Goubau, P; Ruelle, J

2010-01-01

Etravirine is a second-generation non-nucleoside reverse transcriptase inhibitor (NNRTI) with a pattern of resistance mutations quite distinct from the current NNRTIs. We collected all routine samples of HIV-1 patients followed in the AIDS reference laboratory of UCLouvain (in 2006 and 2007) carrying resistance-associated mutations to nevirapine (NVP) or efavirenz (EFV). The sensitivity to Etravirine was estimated using three different drug resistance algorithms: ANRS (July 2008), IAS (December 2008) and Stanford (November 2008). We also verified whether the mutations described as resistance mutations are not due to virus polymorphisms by the study of 58 genotypes of NNRTI-naive patients. Sixty one samples harboured resistance to NVP and EFV: 41/61 had at least one resistance mutation to Etravirine according to ANRS-IAS algorithms; 42/61 samples had at least one resistance mutation to Etravirine according to the Stanford algorithm. 48 and 53 cases were fully sensitive to Etravirine according to ANRS-IAS and Stanford algorithms, respectively. Three cases harboured more than three mutations and presented a pattern of high-degree resistance to Etravirine according to ANRS-IAS algorithm, while one case harboured more than three mutations and presented high degree resistance to Etravirine according to the Stanford algorithm. The V1061 and V179D mutations were more frequent in the ARV-naive group than in the NNRTI-experienced one. According to the currently available algorithms, Etravirine can still be used in the majority of patients with virus showing resistance to NVP and/or EFV, if a combination of other active drugs is included.

Natural History of Gutter-Related Type Ia Endoleaks after Snorkel/Chimney EVAR

PubMed Central

Ullery, Brant W.; Tran, Kenneth; Itoga, Nathan K.; Dalman, Ronald L.; Lee, Jason T.

2018-01-01

Objective Alternative endovascular strategies utilizing parallel or snorkel/chimney (ch-EVAR) techniques have been developed to address the lack of widespread availability and manufacturing limitations with branched/fenestrated aortic devices for the treatment of complex abdominal aortic aneurysms. Despite high technical success and mid-term patency of snorkel stent configurations, concerns remain regarding the perceived increased incidence of early gutter-related type Ia endoleaks. We aimed to evaluate the incidence and natural history of gutter-related type Ia endoleaks following ch-EVAR. Methods Review of medical records and available imaging studies, including completion angiography and serial computed tomographic angiography, was performed for all patients undergoing ch-EVAR at our institution between September 2009 and January 2015. Only procedures involving ≥1 renal artery with or without visceral snorkel stents were included. Primary outcomes of the study were presence and persistence or resolution of early gutter-related type Ia endoleak. Secondary outcomes included aneurysm sac shrinkage and need for secondary intervention related to the presence of type Ia gutter endoleak. Results Sixty patients (mean age, 75.8 ± 7.6 years; male, 70.0%) underwent ch-EVAR with a total of 111 snorkel stents (97 renal [33 bilateral renal], 12 SMA, 2 celiac). A median of 2 (range, 1-4) snorkel stents were placed per patient. Early gutter-related type Ia endoleaks were noted on 30.0% (n=18) of initial postoperative imaging studies. Follow-up imaging revealed spontaneous resolution of these gutter endoleaks in 47.3% and 71.8% of patients at 6- and 12 months post-procedure, respectively. Long-term anticoagulation, degree of oversizing, stent type and diameter, and other clinical/anatomic variables were not significantly associated with presence of gutter endoleaks. Two patients (3.3%) required secondary intervention related to persistent gutter endoleak. At a mean radiologic follow-up of 20.1 months, no difference in mean aneurysm sac size change was observed between those with or without early type Ia gutter endoleak (−6.1 ± 10.0-mm vs. −4.9 ± 11.5-mm, P=.23). Conclusions Gutter-related type Ia endoleaks represent a relatively frequent early occurrence after ch-EVAR, but appears to resolve spontaneously in the majority of cases during early to mid-term follow-up. Given that few ch-EVAR patients require re-intervention related to gutter endoleaks and the presence of such endoleak did not correlate to increased risk for aneurysm sac growth, its natural history may be more benign than originally expected. PMID:28189356

Proposal for management and dermoscopy follow-up of nevi in patients affected by oculocutaneous albinism type Ia.

PubMed

Peralta, Rosario; Sabban, Emilia Cohen; Friedman, Paula; Marcucci, Carolina; Bollea Garlatti, Luis A; Galimberti, Gastón; Cabo, Horacio

2017-01-01

Albino patients are at great risk for developing cutaneous neoplasms, including melanomas. In this paper we describe the dermatoscopic findings of nevi in two patients with oculocutaneous albinism type Ia (OCA-Ia) highlighting that they manifest a vascular pattern similar to that described for amelanotic melanoma. We propose managing these patients with dermoscopy, using the comparative approach, digital follow up (DFU), and reflectance confocal microscopy as a complementary tool for difficult cases.

The Impact of Microlensing on the Standardisation of Strongly Lensed Type Ia Supernovae

NASA Astrophysics Data System (ADS)

Foxley-Marrable, Max; Collett, Thomas E.; Vernardos, Georgios; Goldstein, Daniel A.; Bacon, David

2018-05-01

We investigate the effect of microlensing on the standardisation of strongly lensed Type Ia supernovae (GLSNe Ia). We present predictions for the amount of scatter induced by microlensing across a range of plausible strong lens macromodels. We find that lensed images in regions of low convergence, shear and stellar density are standardisable, where the microlensing scatter is ≲ 0.15 magnitudes, comparable to the intrinsic dispersion of for a typical SN Ia. These standardisable configurations correspond to asymmetric lenses with an image located far outside the Einstein radius of the lens. Symmetric and small Einstein radius lenses (≲ 0.5 arcsec) are not standardisable. We apply our model to the recently discovered GLSN Ia iPTF16geu and find that the large discrepancy between the observed flux and the macromodel predictions from More et al. (2017) cannot be explained by microlensing alone. Using the mock GLSNe Ia catalogue of Goldstein et al. (2017), we predict that ˜ 22% of GLSNe Ia discovered by LSST will be standardisable, with a median Einstein radius of 0.9 arcseconds and a median time-delay of 41 days. By breaking the mass-sheet degeneracy the full LSST GLSNe Ia sample will be able to detect systematics in H0 at the 0.5% level.

The helium star donor channel for the progenitors of Type Ia supernovae

NASA Astrophysics Data System (ADS)

Wang, B.; Meng, X.; Chen, X.; Han, Z.

2009-05-01

Type Ia supernovae (SNe Ia) play an important role in astrophysics, especially in the study of cosmic evolution. Several progenitor models for SNe Ia have been proposed in the past. In this paper we carry out a detailed study of the He star donor channel, in which a carbon-oxygen white dwarf (CO WD) accretes material from a He main-sequence star or a He subgiant to increase its mass to the Chandrasekhar mass. Employing Eggleton's stellar evolution code with an optically thick wind assumption, and adopting the prescription of Kato & Hachisu for the mass accumulation efficiency of the He-shell flashes on to the WDs, we performed binary evolution calculations for about 2600 close WD binary systems. According to these calculations, we mapped out the initial parameters for SNe Ia in the orbital period-secondary mass (logPi - Mi2) plane for various WD masses from this channel. The study shows that the He star donor channel is noteworthy for producing SNe Ia (~1.2 × 10-3yr-1 in our Galaxy), and that the progenitors from this channel may appear as supersoft X-ray sources. Importantly, this channel can explain SNe Ia with short delay times (<~108yr), which is consistent with the recent observational implications of young populations of SN Ia progenitors.

ON THE DEPENDENCE OF TYPE Ia SNe LUMINOSITIES ON THE METALLICITY OF THEIR HOST GALAXIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moreno-Raya, Manuel E.; Mollá, Mercedes; López-Sánchez, Ángel R.

The metallicity of the progenitor system producing a type Ia supernova (SN Ia) could play a role in its maximum luminosity, as suggested by theoretical predictions. We present an observational study to investigate if such a relationship exists. Using the 4.2 m William Herschel Telescope (WHT) we have obtained intermediate-resolution spectroscopy data of a sample of 28 local galaxies hosting SNe Ia, for which distances have been derived using methods independent of those based on SN Ia parameters. From the emission lines observed in their optical spectra, we derived the gas-phase oxygen abundance in the region where each SN Ia exploded. Our datamore » show a trend, with an 80% of chance not being due to random fluctuation, between SNe Ia absolute magnitudes and the oxygen abundances of the host galaxies, in the sense that luminosities tend to be higher for galaxies with lower metallicities. This result seems likely to be in agreement with both the theoretically expected behavior and with other observational results. This dependence M{sub B}–Z might induce systematic errors when it is not considered when deriving SNe Ia luminosities and then using them to derive cosmological distances.« less

Early Childhood Infections and the Risk of Islet Autoimmunity

PubMed Central

Snell-Bergeon, Janet K.; Smith, Jennifer; Dong, Fran; Barón, Anna E.; Barriga, Kathy; Norris, Jill M.; Rewers, Marian

2012-01-01

OBJECTIVE Type 1 diabetes is a common chronic childhood disease, and the incidence is increasing globally. Childhood infections are considered a potential environmental trigger of type 1 diabetes. Alternatively, improved hygiene and reduced childhood infections could explain the increase in type 1 diabetes in developed countries. The association of reported illnesses during infancy and later development of islet autoimmunity (IA) were examined in the Diabetes Autoimmunity Study in the Young. RESEARCH DESIGN AND METHODS Complete illness interviews through 9 months of age were collected for 1,729 children—1,174 without a family history of type 1 diabetes and 555 with a first-degree relative with type 1 diabetes. Persistent IA was defined as positive antibodies to insulin, glutamic acid decarboxylase, or tyrosine phosphatase on at least two consecutive study visits. RESULTS There were 109 children with persistent IA among the 1,729 children with illness records. A greater number of gastrointestinal illnesses were associated with an increased risk of IA, but only among children who were exposed to gluten-containing grains (wheat or barley) either <4 months of age (hazard ratio 1.37 [95% CI 1.22–1.55]; P < 0.0001) or ≥7 months of age (1.12 [1.05–1.19]; P = 0.0005) compared with 4–6 months of age (P for interaction = 0.02). There were no associations of upper respiratory symptoms, respiratory illnesses, or fevers with IA. CONCLUSIONS Specific pathogens such as enteroviruses or rotavirus may increase the risk of IA in the presence of existing inflammation induced by diet. PMID:23043167

Arsenic Exposure and Type 2 Diabetes: MicroRNAs as Mechanistic Links?

PubMed

Beck, Rowan; Styblo, Miroslav; Sethupathy, Praveen

2017-03-01

The goal of this review is to delineate the following: (1) the primary means of inorganic arsenic (iAs) exposure for human populations, (2) the adverse public health outcomes associated with chronic iAs exposure, (3) the pathophysiological connection between arsenic and type 2 diabetes (T2D), and (4) the incipient evidence for microRNAs as candidate mechanistic links between iAs exposure and T2D. Exposure to iAs in animal models has been associated with the dysfunction of several different cell types and tissues, including liver and pancreatic islets. Many microRNAs that have been identified as responsive to iAs exposure under in vitro and/or in vivo conditions have also been shown in independent studies to regulate processes that underlie T2D etiology, such as glucose-stimulated insulin secretion from pancreatic beta cells. Defects in insulin secretion could be, in part, associated with aberrant microRNA expression and activity. Additional in vivo studies need to be performed with standardized concentrations and durations of arsenic exposure in order to evaluate rigorously microRNAs as molecular drivers of iAs-associated diabetes.

Genetic investigations on intracranial aneurysm: update and perspectives.

PubMed

Bourcier, Romain; Redon, Richard; Desal, Hubert

2015-04-01

Detection of an intracranial aneurysm (IA) is a common finding in MRI practice. Nowadays, the incidence of unruptured IA seems to be increasing with the continuous evolution of imaging techniques. Important modifiable risk factors for SAH are well defined, but familial history of IA is the best risk marker for the presence of IA. Numerous heritable conditions are associated with IA formation but these syndromes account for less than 1% of all IAs in the population. No diagnostic test based on genetic knowledge is currently available to identify theses mutations and patients who are at higher risk for developing IAs. In the longer term, a more comprehensive understanding of independent and interdependent molecular pathways germane to IA formation and rupture may guide the physician in developing targeted therapies and optimizing prognostic risk assessment. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Search for Type Ia supernova progenitors in open star clusters

NASA Astrophysics Data System (ADS)

Chakraborty, Subho

2013-12-01

Though Type Ia supernovae (henceforth SNae) are a primary tool in refining our understanding of cosmology and dark energy, controversies still abound regarding what the progenitors of these SNae are. The two main classes of possible Type Ia SN progenitors are: (1) the single-degenerate model, where a white dwarf (the remnant of a Sun-like star that has completed its life cycle) gravitationally accretes material from a close companion star, and (2) the double-degenerate model, involving the merger of two white dwarfs. In either case, the resulting SN explosion looks the same superficially. But some of the details of the SNae, perhaps including details critical to understanding dark energy, may depend sensitively on what the progenitors are. The goal of this thesis was to search for radial velocity variations in two candidate double degenerate systems. Firstly, I determined if either of these systems were bona fide double degenerates. I used the well-tested method of searching for radial velocity variations due to orbital motion as determined by changing Doppler shifts in their optical spectra. These data were obtained from time-series spectra of both candidate systems over several hours at the world's largest ground based optical telescope, the Keck Observatory in Hawaii. Secondly, I tested whether each confirmed binary system is of sufficient mass and sufficiently short orbital period to be progenitors of a future Type Ia SN. Binary white dwarfs that will merge to form Type IaSNae over a Hubble time have orbital periods less than six hours, which are easily detectable with these data. Type Ia SN progenitors must also have a mass near or above the Chandrasekhar limit of ~1.44 solar masses; the total mass of these systems can also be determined from our data. If one or both of these candidate systems had met both these criteria, the white dwarfs would have been the first definitive examples of the double degenerate class of Type Ia progenitors. This result, which we refer to as a positive result, would have been extremely important and highly impactful in astronomical research.

SN 2010LP—A TYPE IA SUPERNOVA FROM A VIOLENT MERGER OF TWO CARBON-OXYGEN WHITE DWARFS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kromer, M.; Taubenberger, S.; Seitenzahl, I. R.

2013-11-20

SN 2010lp is a subluminous Type Ia supernova (SN Ia) with slowly evolving lightcurves. Moreover, it is the only subluminous SN Ia observed so far that shows narrow emission lines of [O I] in late-time spectra, indicating unburned oxygen close to the center of the ejecta. Most explosion models for SNe Ia cannot explain the narrow [O I] emission. Here, we present hydrodynamic explosion and radiative transfer calculations showing that the violent merger of two carbon-oxygen white dwarfs of 0.9 and 0.76 M {sub ☉} adequately reproduces the early-time observables of SN 2010lp. Moreover, our model predicts oxygen close tomore » the center of the explosion ejecta, a pre-requisite for narrow [O I] emission in nebular spectra as observed in SN 2010lp.« less

Host galaxies of type ia supernovae from the nearby supernova factory

NASA Astrophysics Data System (ADS)

Childress, Michael Joseph

Type Ia Supernovae (SNe Ia) are excellent distance indicators, yet the full details of the underlying physical mechanism giving rise to these dramatic stellar deaths remain unclear. As large samples of cosmological SNe Ia continue to be collected, the scatter in brightnesses of these events is equally affected by systematic errors as statistical. Thus we need to understand the physics of SNe Ia better, and in particular we must know more about the progenitors of these SNe so that we can derive better estimates for their true intrinsic brightnesses. The host galaxies of SNe Ia provide important indirect clues as to the nature of SN Ia progenitors. In this Thesis we utilize the host galaxies of SNe Ia discovered by the Nearby Supernova Factory (SNfactory) to pursue several key investigations into the nature of SN Ia progenitors and their effects on SN Ia brightnesses. We first examine the host galaxy of SN 2007if, an important member of the subclass of SNe Ia whose extreme brightnesses indicate a progenitor that exceeded the canonical Chandrasekhar-mass value presumed for normal SNe Ia, and show that the host galaxy of this SN is composed of very young stars and has extremely low metallicity, providing important constraints on progenitor scenarios for this SN. We then utilize the full sample of SNfactory host galaxy masses (measured from photometry) and metallicities (derived from optical spectroscopy) to examine several global properties of SN Ia progenitors: (i) we show that SN Ia hosts show tight agreement with the normal galaxy mass-metallicity relation; (ii) comparing the observed distribution of SN Ia host galaxy masses to a theoretical model that couples galaxy physics to the SN Ia delay time distribution (DTD), we show the power of the SN Ia host mass distribution in constraining the SN Ia DTD; and (iii) we show that the lack of ultra-low metallicities in the SNfactory SN Ia host sample gives provisional support for the theorized low-metallicity inhibition of SNe Ia. Finally we revisit recent studies which found that the corrected brightnesses of SNe Ia (after application of the standard light curve width and color corrections) correlate with the masses of their host galaxies. We confirm this trend with host mass using SNfactory data, and for the first time confirm that an analogous trend exists with host metallicity. We then apply a spectroscopic standardization technique developed by SNfactory and show that this method significantly reduces the observed bias. In this Thesis we show that SN Ia host galaxies continue to provide key insight into SN Ia progenitors, and also illuminate possible biases in SN Ia brightness standardization techniques.

Hierarchical Models for Type Ia Supernova Light Curves in the Optical and Near Infrared

NASA Astrophysics Data System (ADS)

Mandel, Kaisey; Narayan, G.; Kirshner, R. P.

2011-01-01

I have constructed a comprehensive statistical model for Type Ia supernova optical and near infrared light curves. Since the near infrared light curves are excellent standard candles and are less sensitive to dust extinction and reddening, the combination of near infrared and optical data better constrains the host galaxy extinction and improves the precision of distance predictions to SN Ia. A hierarchical probabilistic model coherently accounts for multiple random and uncertain effects, including photometric error, intrinsic supernova light curve variations and correlations across phase and wavelength, dust extinction and reddening, peculiar velocity dispersion and distances. An improved BayeSN MCMC code is implemented for computing probabilistic inferences for individual supernovae and the SN Ia and host galaxy dust populations. I use this hierarchical model to analyze nearby Type Ia supernovae with optical and near infared data from the PAIRITEL, CfA3, and CSP samples and the literature. Using cross-validation to test the robustness of the model predictions, I find that the rms Hubble diagram scatter of predicted distance moduli is 0.11 mag for SN with optical and near infrared data versus 0.15 mag for SN with only optical data. Accounting for the dispersion expected from random peculiar velocities, the rms intrinsic prediction error is 0.08-0.10 mag for SN with both optical and near infrared light curves. I discuss results for the inferred intrinsic correlation structures of the optical-NIR SN Ia light curves and the host galaxy dust distribution captured by the hierarchical model. The continued observation and analysis of Type Ia SN in the optical and near infrared is important for improving their utility as precise and accurate cosmological distance indicators.

A Hubble Diagram of Distant Type IA Supernovae

NASA Astrophysics Data System (ADS)

Hamuy, M.; Phillips, M. M.; Suntzeff, N. B.; Aviles, R.; Maza, J.

1993-12-01

Due to their extreme luminosities at maximum light, type Ia supernovae (SNe Ia) have long been considered among the most attractive cosmological standard candles. Although nearly all work to date has been devoted to attempts to use these objects to determine the local rate of expansion of the universe (Ho), SNe Ia also provide one of the few direct techniques for measuring the deceleration parameter qo. However, in a recent study of nine well-observed events based largely on data obtained at CTIO, Phillips (1993, ApJ, 413, L105) found clear evidence for a significant intrinsic dispersion in SNe Ia absolute magnitudes amounting to ~ 0.8 mag in B, ~ 0.7 mag in V, and ~ 0.5 mag in I. Such a range in peak luminosity could introduce a subtantial Malmquist bias into searches for distant (z <= 0.3) SNe Ia which, if uncorrected, could lead to an erroneous value of qo. In this paper we present the Hubble diagram for 13 SNe Ia discovered and observed in the course of the Calan/Tololo Supernova Survey. This sample, which covers the redshift range 0.01 <= z <= 0.1, provides unequivocal evidence for an intrinsic spread in the peak luminosities of type Ia events. The data also confirm Phillips' conclusion that the maximum-light luminosity is strongly correlated with the initial decline rate of the B light curve. Interestingly, the most luminous SNe in our sample all occurred in spiral galaxies, which is true for Phillips' sample of nearby SNe Ia as well. This is opposite to what one would expect if dust extinction were important. These findings are consistent with recent speculations that the progenitors of SNe Ia are white dwarfs covering a range of masses, and also suggest that the brightest events may be found in galaxies which are still actively forming stars. The implications for the use of SNe Ia to measure qo are briefly discussed. This research has been supported by Grant 92/0312 from Fondo Nacional de Ciencias y Tecnología (FONDECYT-Chile).

Prevention of complications in glycogen storage disease type Ia with optimization of metabolic control.

PubMed

Dambska, M; Labrador, E B; Kuo, C L; Weinstein, D A

2017-08-01

Prior to 1971, type Ia glycogen storage disease was marked by life-threatening hypoglycemia, lactic acidosis, severe failure to thrive, and developmental delay. With the introduction of continuous feeds in the 1970s and cornstarch in the 1980s, the prognosis improved, but complications almost universally developed. Changes in the management of type Ia glycogen storage disease have resulted in improved metabolic control, and this manuscript reviews the increasing evidence that complications can be delayed or prevented with optimal metabolic control as previously was seen in diabetes. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Outcome-based anatomic criteria for defining the hostile aortic neck.

PubMed

Jordan, William D; Ouriel, Kenneth; Mehta, Manish; Varnagy, David; Moore, William M; Arko, Frank R; Joye, James; de Vries, Jean-Paul P M

2015-06-01

There is abundant evidence linking hostile proximal aortic neck anatomy to poor outcome after endovascular aortic aneurysm repair (EVAR), yet the definition of hostile anatomy varies from study to study. This current analysis was undertaken to identify anatomic criteria that are most predictive of success or failure at the aortic neck after EVAR. The study group comprised 221 patients in the Aneurysm Treatment using the Heli-FX Aortic Securement System Global Registry (ANCHOR) clinical trial, a population enriched with patients with challenging aortic neck anatomy and failure of sealing. Imaging protocols were not protocol specified but were performed according to the institution's standard of care. Core laboratory analysis assessed the three-dimensional centerline-reformatted computed tomography scans. Failure at the aortic neck was defined by type Ia endoleak occurring at the time of the initial endograft implantation or during follow-up. Receiver operating characteristic curve analysis was used to assess the value of each anatomic measure in the classification of aortic neck success and failure and to identify optimal thresholds of discrimination. Binary logistic regression was performed after excluding highly intercorrelated variables, creating a final model with significant predictors of outcome after EVAR. Among the 221 patients, 121 (54.8%) remained free of type Ia endoleak and 100 (45.2%) did not. Type Ia endoleaks presented immediately after endograft deployment in 58 (58.0%) or during follow-up in 42 (42.0%). Receiver operating characteristic curve analysis identified 12 variables where the classification of patients with type Ia endoleak was significantly more accurate than chance alone. Increased aortic neck diameter at the lowest renal artery (P = .013) and at 5 mm (P = .008), 10 mm (P = .008), and 15 mm (P = .010) distally; aneurysm sac diameter (P = .001), common iliac artery diameters (right, P = .012; left, P = .032), and a conical (P = .049) neck configuration were predictive of endoleak. By contrast, increased aortic neck length (P = .050), a funnel-shaped aortic neck (P = .036), and neck mural thrombus content, as measured by average thickness (P = .044) or degrees of circumferential coverage (P = .029), were protective against endoleak. Binary logistic regression identified three variables independently predictive of type Ia endoleak. Neck diameter at the lowest renal artery (P = .002, cutpoint 26 mm) and neck length (P = .017, cutpoint 17 mm) were associated with endoleak, whereas some mural neck thrombus content was protective (P = .001, cutpoint 11° of circumferential coverage). A limited number of independent anatomic variables are predictive of type Ia endoleak after EVAR, including aortic neck diameter and aortic neck length, whereas mural thrombus in the neck is protective. This study suggests that anatomic measures with identifiable threshold cutpoints should be considered when defining the hostile aortic neck and assessing the risk of complications after EVAR. Copyright © 2015 Society for Vascular Surgery. All rights reserved.

Type Ia supernovae: explosions and progenitors

NASA Astrophysics Data System (ADS)

Kerzendorf, Wolfgang Eitel

2011-08-01

Supernovae are the brightest explosions in the universe. Supernovae in our Galaxy, rare and happening only every few centuries, have probably been observed since the beginnings of mankind. At first they were interpreted as religious omens but in the last half millennium they have increasingly been used to study the cosmos and our place in it. Tycho Brahe deduced from his observations of the famous supernova in 1572, that the stars, in contrast to the widely believe Aristotelian doctrine, were not immutable. More than 400 years after Tycho made his paradigm changing discovery using SN 1572, and some 60 years after supernovae had been identified as distant dying stars, two teams changed the view of the world again using supernovae. The found that the Universe was accelerating in its expansion, a conclusion that could most easily be explained if more than 70% of the Universe was some previously un-identified form of matter now often referred to as `Dark Energy'. Beyond their prominent role as tools to gauge our place in the Universe, supernovae themselves have been studied well over the past 75 years. We now know that there are two main physical causes of these cataclysmic events. One of these channels is the collapse of the core of a massive star. The observationally motivated classes Type II, Type Ib and Type Ic have been attributed to these events. This thesis, however is dedicated to the second group of supernovae, the thermonuclear explosions of degenerate carbon and oxygen rich material and lacking hydrogen - called Type Ia supernovae (SNe Ia). White dwarf stars are formed at the end of a typical star's life when nuclear burning ceases in the core, the outer envelope is ejected, with the degenerate core typically cooling for eternity. Theory predicts that such stars will self ignite when close to 1.38 Msun (called the Chandrasekhar Mass). Most stars however leave white dwarfs with 0.6 Msun, and no star leaves a remnant as heavy as 1.38 M! sun, which suggests that they somehow need to acquire mass if they are to explode as SN Ia. Currently there are two major scenarios for this mass acquisition. In the favoured single degenerate scenario the white dwarf accretes matter from a companion star which is much younger in its evolutionary state. The less favoured double degenerate scenario sees the merger of two white dwarfs (with a total combined mass of more than 1.38 Msun). This thesis has tried to answer the question about the mass acquisition in two ways. First the single degenerate scenario predicts a surviving companion post-explosion. We undertook an observational campaign to find this companion in two ancient supernovae (SN 1572 and SN 1006). Secondly, we have extended an existing code to extract the elemental and energy yields of SNe Ia spectra by automating spectra fitting to specific SNe Ia. This type of analysis, in turn, help diagnose to which of the two major progenitor scenarios is right.

The activity of spontaneous action potentials in developing hair cells is regulated by Ca(2+)-dependence of a transient K+ current.

PubMed

Levic, Snezana; Lv, Ping; Yamoah, Ebenezer N

2011-01-01

Spontaneous action potentials have been described in developing sensory systems. These rhythmic activities may have instructional roles for the functional development of synaptic connections. The importance of spontaneous action potentials in the developing auditory system is underpinned by the stark correlation between the time of auditory system functional maturity, and the cessation of spontaneous action potentials. A prominent K(+) current that regulates patterning of action potentials is I(A). This current undergoes marked changes in expression during chicken hair cell development. Although the properties of I(A) are not normally classified as Ca(2+)-dependent, we demonstrate that throughout the development of chicken hair cells, I(A) is greatly reduced by acute alterations of intracellular Ca(2+). As determinants of spike timing and firing frequency, intracellular Ca(2+) buffers shift the activation and inactivation properties of the current to more positive potentials. Our findings provide evidence to demonstrate that the kinetics and functional expression of I(A) are tightly regulated by intracellular Ca(2+). Such feedback mechanism between the functional expression of I(A) and intracellular Ca(2+) may shape the activity of spontaneous action potentials, thus potentially sculpting synaptic connections in an activity-dependent manner in the developing cochlea. © 2011 Levic et al.

Berkeley SuperNova Ia Program (BSNIP): Initial Spectral Analysis

NASA Astrophysics Data System (ADS)

Silverman, Jeffrey; Kong, J.; Ganeshalingam, M.; Li, W.; Filippenko, A. V.

2011-01-01

The Berkeley SuperNova Ia Program (BSNIP) has been observing nearby (z < 0.1) Type Ia supernovae (SNe Ia) both photometrically and spectroscopically for over two decades. Using telescopes at both Lick and Keck Observatories, we have amassed an extensive collection of well-sampled optical light curves with complementary spectra covering, on average, 3400-10,000 Å. In total, we have obtained nearly 600 spectra of over 200 SNe Ia with densely sampled multi-color light curves. The initial analysis of this dataset consists of accurately and robustly measuring the strength and position of various spectral features near maximum brightness. We determine the endpoints, pseudo-continuum, expansion velocity, equivalent width, and depth of each major feature observed in our wavelength range. For objects with multiple spectra near maximum brightness we investigate how these values change with time. From these measurements we also calculate velocity gradients and various flux ratios within a given spectrum which will allow us to explore correlations between spectral and photometric observables. Some possible correlations have been studied previously, but our dataset is unique in how self-consistent the data reduction and spectral feature measurements have been, and it is a factor of a few larger than most earlier studies. We will briefly summarize the contents of the full dataset as an introduction to our initial analysis. Some of our measurements of SN Ia spectral features, along with a few initial results from those measurements, will be presented. Finally, we will comment on our current progress and planned future work. We gratefully acknowledge the financial support of NSF grant AST-0908886, the TABASGO Foundation, and the Marc J. Staley Graduate Fellowship in Astronomy.

The prevalence of early subclinical somatic neuropathy in children and adolescents with Type 1 diabetes mellitus and its association with the persistence of autoantibodies to glutamic acid decarboxylase (GAD) and islet antigen-2 (IA-2).

PubMed

Louraki, Maria; Katsalouli, Marina; Kanaka-Gantenbein, Christina; Kafassi, Nikolitsa; Critselis, Eleni; Kallinikou, Dimitra; Tsentidis, Charalampos; Karavanaki, Kyriaki

2016-07-01

To evaluate the prevalence of early somatic neuropathy in children and adolescents with Type 1 diabetes mellitus (Type 1 DM) and its association with the presence of glutamic acid decarboxylase and islet antigen-2 autoantibodies (GADA and IA-2A). A cross-sectional study was conducted in a hospital-based cohort of pediatric Type 1 DM patients (n=85, mean(±SD) age: 13.5±3.4years, mean(±SD) disease duration 5.5±3.4years). Peripheral neuropathy was assessed with nerve conduction studies (NCS). GADA and IA-2A titers were measured with radioligand assays. Among the study population, 34.1% had at least one abnormal electrophysiological parameter, although predominantly asymptomatic. The highest rates of abnormality were detected in sensory peroneal nerve (25.9%) followed by sural nerve (15.3%). Affected patients were not different in terms of age, diabetes duration or glycaemic control. Among the participants, 62.4% had positive GADA, 58.8% positive IA-2A and 42.4% double antibody positivity. Abnormal NCS correlated neither with GADA nor with IA-2A levels or positivity. However lower sensory nerve action potential in the peroneal nerve, indicative of early axonal dysfunction, was observed in patients with GADA or IA-2A positivity. Absence of both antibodies was associated with better action potentials in all the examined nerves of the lower limbs. Impaired indices of subclinical peripheral primarily sensory neuropathy were present among one third of Type 1 DM children and adolescents, with no impact of diabetes duration or glycaemic control. GADA and IA-2A seem to be involved in the development of axonal degeneration, in a pathway which remains to be identified. Copyright © 2016. Published by Elsevier Ireland Ltd.

A TYPE Ia SUPERNOVA AT REDSHIFT 1.55 IN HUBBLE SPACE TELESCOPE INFRARED OBSERVATIONS FROM CANDELS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodney, Steven A.; Riess, Adam G.; Jones, David O.

2012-02-10

We report the discovery of a Type Ia supernova (SN Ia) at redshift z = 1.55 with the infrared detector of the Wide Field Camera 3 (WFC3-IR) on the Hubble Space Telescope (HST). This object was discovered in CANDELS imaging data of the Hubble Ultra Deep Field and followed as part of the CANDELS+CLASH Supernova project, comprising the SN search components from those two HST multi-cycle treasury programs. This is the highest redshift SN Ia with direct spectroscopic evidence for classification. It is also the first SN Ia at z > 1 found and followed in the infrared, providing amore » full light curve in rest-frame optical bands. The classification and redshift are securely defined from a combination of multi-band and multi-epoch photometry of the SN, ground-based spectroscopy of the host galaxy, and WFC3-IR grism spectroscopy of both the SN and host. This object is the first of a projected sample at z > 1.5 that will be discovered by the CANDELS and CLASH programs. The full CANDELS+CLASH SN Ia sample will enable unique tests for evolutionary effects that could arise due to differences in SN Ia progenitor systems as a function of redshift. This high-z sample will also allow measurement of the SN Ia rate out to z Almost-Equal-To 2, providing a complementary constraint on SN Ia progenitor models.« less

Characterization of the Impaired Glucose Homeostasis Produced in C57BL/6 Mice by Chronic Exposure to Arsenic and High-Fat Diet

PubMed Central

Paul, David S.; Walton, Felecia S.; Saunders, R. Jesse

2011-01-01

Background: Type 2 diabetes is characterized by glucose intolerance and insulin resistance. Obesity is the leading cause of type 2 diabetes. Growing evidence suggests that chronic exposure to inorganic arsenic (iAs) also produces symptoms consistent with diabetes. Thus, iAs exposure may further increase the risk of diabetes in obese individuals. Objectives: Our goal was to characterize diabetogenic effects of iAs exposure and high-fat diet (HFD) in weaned C57BL/6 mice. Methods: Mice were fed HFD or low-fat diet (LFD) while exposed to iAs in drinking water (25 or 50 ppm As) for 20 weeks; control HFD and LFD mice drank deionized water. Body mass and adiposity were monitored throughout the study. We measured glucose and insulin levels in fasting blood and in blood collected during oral glucose tolerance tests (OGTT) to evaluate the diabetogenic effects of the treatment. Results: Control mice fed HFD accumulated more fat, had higher fasting blood glucose, and were more insulin resistant than were control LFD mice. However, these diabetes indicators decreased with iAs intake in a dose-dependent manner. OGTT showed impaired glucose tolerance for both control and iAs-treated HFD mice compared with respective LFD mice. Notably, glucose intolerance was more pronounced in HFD mice treated with iAs despite a significant decrease in adiposity, fasting blood glucose, and insulin resistance. Conclusions: Our data suggest that iAs exposure acts synergistically with HFD-induced obesity in producing glucose intolerance. However, mechanisms of the diabetogenic effects of iAs exposure may differ from the mechanisms associated with the obesity-induced type 2 diabetes. PMID:21592922

Creation of a Unified Set of Core-Collapse Supernovae for Training of Photometric Classifiers

NASA Astrophysics Data System (ADS)

D'Arcy Kenworthy, William; Scolnic, Daniel; Kessler, Richard

2017-01-01

One of the key tasks for future supernova cosmology analyses is to photometrically distinguish type Ia supernovae (SNe) from their core collapse (CC) counterparts. In order to train programs for this purpose, it is necessary to train on a large number of core-collapse SNe. However, there are only a handful used for current programs. We plan to use the large amount of CC lightcurves available on the Open Supernova Catalog (OSC). Since this data is scraped from many different surveys, it is given in a number of photometric systems with different calibration and filters. We therefore created a program to fit smooth lightcurves (as a function of time) to photometric observations of arbitrary SNe. The Supercal method is then used to translate the smoothed lightcurves to a single photometric system. We can thus compile a training set of 782 supernovae, of which 127 are not type Ia. These smoothed lightcurves are also being contributed upstream to the OSC as derived data.

Consistency among distance measurements: transparency, BAO scale and accelerated expansion

NASA Astrophysics Data System (ADS)

Avgoustidis, Anastasios; Verde, Licia; Jimenez, Raul

2009-06-01

We explore consistency among different distance measures, including Supernovae Type Ia data, measurements of the Hubble parameter, and determination of the Baryon acoustic oscillation scale. We present new constraints on the cosmic transparency combining H(z) data together with the latest Supernovae Type Ia data compilation. This combination, in the context of a flat ΛCDM model, improves current constraints by nearly an order of magnitude although the constraints presented here are parametric rather than non-parametric. We re-examine the recently reported tension between the Baryon acoustic oscillation scale and Supernovae data in light of possible deviations from transparency, concluding that the source of the discrepancy may most likely be found among systematic effects of the modelling of the low redshift data or a simple ~ 2-σ statistical fluke, rather than in exotic physics. Finally, we attempt to draw model-independent conclusions about the recent accelerated expansion, determining the acceleration redshift to be zacc = 0.35+0.20-0.13 (1-σ).

Gene Therapy Vector for the Treatment of Glycogen Storage Disease Type Ia (GSD-Ia) | NCI Technology Transfer Center | TTC

Cancer.gov

GSD-Ia is an inherited disorder of metabolism associated with life-threatening hypoglycemia, hepatic malignancy, and renal failure caused by the deficiency of glucose-6-phosphatase-alpha (G6Pase-alpha or G6PC). NICHD seeks parties to license this invention towards commercialization.

Elemental gas-phase abundances of intermediate redshift type Ia supernova star-forming host galaxies

NASA Astrophysics Data System (ADS)

Moreno-Raya, M. E.; Galbany, L.; López-Sánchez, Á. R.; Mollá, M.; González-Gaitán, S.; Vílchez, J. M.; Carnero, A.

2018-05-01

The maximum luminosity of type Ia supernovae (SNe Ia) depends on the oxygen abundance of the regions of the host galaxies, where they explode. This metallicity dependence reduces the dispersion in the Hubble diagram (HD) when included with the traditional two-parameter calibration of SN Ia light-curve parameters and absolute magnitude. In this work, we use empirical calibrations to carefully estimate the oxygen abundance of galaxies hosting SNe Ia from the SDSS-II/SN (Sloan Digital Sky Survey-II Supernova) survey at intermediate redshift by measuring their emission-line intensities. We also derive electronic temperature with the direct method for a small fraction of objects for consistency. We find a trend of decreasing oxygen abundance with increasing redshift for the most massive galaxies. Moreover, we study the dependence of the HD residuals (HR) with galaxy oxygen abundance obtaining a correlation in line with those found in other works. In particular, the HR versus oxygen abundance shows a slope of -0.186 ± 0.123 mag dex-1 (1.52σ) in good agreement with theoretical expectations. This implies smaller distance modulii after corrections for SNe Ia in metal-rich galaxies. Based on our previous results on local SNe Ia, we propose this dependence to be due to the lower luminosity of the SNe Ia produced in more metal-rich environments.

Pathogenesis of growth failure and partial reversal with gene therapy in murine and canine Glycogen Storage Disease type Ia.

PubMed

Brooks, Elizabeth Drake; Little, Dianne; Arumugam, Ramamani; Sun, Baodong; Curtis, Sarah; Demaster, Amanda; Maranzano, Michael; Jackson, Mark W; Kishnani, Priya; Freemark, Michael S; Koeberl, Dwight D

2013-06-01

Glycogen Storage Disease type Ia (GSD-Ia) in humans frequently causes delayed bone maturation, decrease in final adult height, and decreased growth velocity. This study evaluates the pathogenesis of growth failure and the effect of gene therapy on growth in GSD-Ia affected dogs and mice. Here we found that homozygous G6pase (-/-) mice with GSD-Ia have normal growth hormone (GH) levels in response to hypoglycemia, decreased insulin-like growth factor (IGF) 1 levels, and attenuated weight gain following administration of GH. Expression of hepatic GH receptor and IGF 1 mRNAs and hepatic STAT5 (phospho Y694) protein levels are reduced prior to and after GH administration, indicating GH resistance. However, restoration of G6Pase expression in the liver by treatment with adeno-associated virus 8 pseudotyped vector expressing G6Pase (AAV2/8-G6Pase) corrected body weight, but failed to normalize plasma IGF 1 in G6pase (-/-) mice. Untreated G6pase (-/-) mice also demonstrated severe delay of growth plate ossification at 12 days of age; those treated with AAV2/8-G6Pase at 14 days of age demonstrated skeletal dysplasia and limb shortening when analyzed radiographically at 6 months of age, in spite of apparent metabolic correction. Moreover, gene therapy with AAV2/9-G6Pase only partially corrected growth in GSD-Ia affected dogs as detected by weight and bone measurements and serum IGF 1 concentrations were persistently low in treated dogs. We also found that heterozygous GSD-Ia carrier dogs had decreased serum IGF 1, adult body weights and bone dimensions compared to wild-type littermates. In sum, these findings suggest that growth failure in GSD-Ia results, at least in part, from hepatic GH resistance. In addition, gene therapy improved growth in addition to promoting long-term survival in dogs and mice with GSD-Ia. Copyright © 2013 Elsevier Inc. All rights reserved.

Pathogenesis of growth failure and partial reversal with gene therapy in murine and canine Glycogen Storage Disease type Ia

PubMed Central

Brooks, Elizabeth Drake; Little, Dianne; Arumugam, Ramamani; Sun, Baodong; Curtis, Sarah; DeMaster, Amanda; Maranzano, Michael; Jackson, Mark W.; Kishnani, Priya; Freemark, Michael S.; Koeberl, Dwight D.

2013-01-01

Glycogen Storage Disease type Ia (GSD-Ia) in humans frequently causes delayed bone maturation, decrease in final adult height, and decreased growth velocity. This study evaluates the pathogenesis of growth failure and the effect of gene therapy on growth in GSD-Ia affected dogs and mice. Here we found that homozygous G6pase (−/−) mice with GSD-Ia have normal growth hormone (GH) levels in response to hypoglycemia, decreased insulin-like growth factor (IGF) 1 levels, and attenuated weight gain following administration of GH. Expression of hepatic GH receptor and IGF 1 mRNAs and hepatic STAT5 (phospho Y694) protein levels are reduced prior to and after GH administration, indicating GH resistance. However, restoration of G6Pase expression in the liver by treatment with adeno-associated virus 8 pseudotyped vector expressing G6Pase (AAV2/8-G6Pase) corrected body weight, but failed to normalize plasma IGF 1 in G6pase (−/−) mice. Untreated G6pase (−/−) mice also demonstrated severe delay of growth plate ossification at 12 days of age; those treated with AAV2/8-G6Pase at 14 days of age demonstrated skeletal dysplasia and limb shortening when analyzed radiographically at 6 months of age, in spite of apparent metabolic correction. Moreover, gene therapy with AAV2/9-G6Pase only partially corrected growth in GSD-Ia affected dogs as detected by weight and bone measurements and serum IGF 1 concentrations were persistently low in treated dogs. We also found that heterozygous GSD-Ia carrier dogs had decreased serum IGF 1, adult body weights and bone dimensions compared to wild-type littermates. In sum, these findings suggest that growth failure in GSD-Ia results, at least in part, from hepatic GH resistance. In addition, gene therapy improved growth in addition to promoting long-term survival in dogs and mice with GSD-Ia. PMID:23623482

Health economics analysis of insulin aspart vs. regular human insulin in type 2 diabetes patients, based on observational real life evidence from general practices in Germany.

PubMed

Liebl, A; Seitz, L; Palmer, A J

2014-10-01

A retrospective analysis of German general practice data demonstrated that insulin aspart (IA) was associated with a significantly reduced incidence of macrovascular events (MVE: stroke, myocardial infarction, peripheral vascular disease or coronary heart disease) vs. regular human insulin (RHI) in type 2 diabetes patients. Economic implications, balanced against potential improvements in quality-adjusted life years (QALYs) resulting from lower risks of complications with IA in this setting have not yet been explored. A decision analysis model was developed utilizing 3-year initial MVE rates for each comparator, combined with published German-specific insulin and MVE costs and health utilities to calculate number needed to treat (NNT) to avoid any MVE, incremental costs and QALYs gained/ person for IA vs. RHI. A 3-year time horizon and German 3(rd)-party payer perspective were used. Probabilistic sensitivity analysis was performed, sampling from distributions of key parameters. Additional sensitivity analyses were performed. NNT over a 3 year period to avoid any MVE was 8 patients for IA vs. RHI. Due to lower MVE rates, IA dominated RHI with 0.020 QALYs gained (95% confidence interval: 0.014-0.025) and cost savings of EUR 1 556 (1 062-2 076)/person for IA vs. RHI over the 3-year time horizon. Sensitivity analysis revealed that IA would still be overall cost saving even if the cost of IA was double the cost/unit of RHI. From a health economics perspective, IA was the superior alternative for the insulin treatment of type 2 diabetes, with lower incidence of MVE events translating to improved QALYs and lower costs vs. RHI within a 3-year time horizon. © J. A. Barth Verlag in Georg Thieme Verlag KG Stuttgart · New York.

30 CFR 57.22215 - Separation of intake and return air (I-A, II-A, III, and V-A mines).

Code of Federal Regulations, 2010 CFR

2010-07-01

... Separation of intake and return air (I-A, II-A, III, and V-A mines). Main intake and return air currents... for separation of air currents. Such wall or partition shall be constructed of reinforced concrete or... separation of main air currents in the same opening. Flexible ventilation tubing shall not exceed 250 feet in...

30 CFR 57.22215 - Separation of intake and return air (I-A, II-A, III, and V-A mines).

Code of Federal Regulations, 2011 CFR

2011-07-01

... Separation of intake and return air (I-A, II-A, III, and V-A mines). Main intake and return air currents... for separation of air currents. Such wall or partition shall be constructed of reinforced concrete or... separation of main air currents in the same opening. Flexible ventilation tubing shall not exceed 250 feet in...

De Sitter universe described by a binary mixture with a variable cosmological constant λ

NASA Astrophysics Data System (ADS)

Biswal, S. K.

2018-04-01

We have constructed a self-consistent system of Bianchi Type VI0 cosmology, and mingling of perfect fluid and dark energy in five dimensions. The usual equation of state p = γ ρ with γ \\in [0, 1] is chosen by the perfect fluid. The dark energy assumed to be chosen is taken into consideration to be either the quintessence or Chaplygin gas. The same solutions pertaining to the corresponding the field equations of Einstein are obtained as a quadrature. State parameter's equations for dark energy ω is found to be consistent enough with the recent observations of SNe Ia data (SNe Ia data with CMBR anisotropy) and galaxy clustering statistics. Here our models predict that the rate of expansion of Universe would increase with passage of time. The cosmological constant Λ is traced as a declining function of time and it gets nearer to a small positive value later on which is supported by the results from the current supernovae Ia observations. Also a detail discussion is made on the physical and geometrical aspects of the models.

THE BIRTH RATE OF SNe Ia FROM HYBRID CONe WHITE DWARFS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meng, Xiangcun; Podsiadlowski, Philipp, E-mail: xiangcunmeng@ynao.ac.cn

Considering the uncertainties of the C-burning rate (CBR) and the treatment of convective boundaries, Chen et al. found that there is a regime where it is possible to form hybrid CONe white dwarfs (WDs), i.e., ONe WDs with carbon-rich cores. As these hybrid WDs can be as massive as 1.30 M {sub ☉}, not much mass needs to be accreted for these objects to reach the Chandrasekhar limit and to explode as Type Ia supernovae (SNe Ia). We have investigated their contribution to the overall SN Ia birth rate and found that such SNe Ia tend to be relatively youngmore » with typical time delays between 0.1 and 1 Gyr, where some may be as young as 30 Myr. SNe Ia from hybrid CONe WDs may contribute several percent to all SNe Ia, depending on the common-envelope ejection efficiency and the CBR. We suggest that these SNe Ia may produce part of the 2002cx-like SN Ia class.« less

Natural history of gutter-related type Ia endoleaks after snorkel/chimney endovascular aneurysm repair.

PubMed

Ullery, Brant W; Tran, Kenneth; Itoga, Nathan K; Dalman, Ronald L; Lee, Jason T

2017-04-01

Alternative endovascular strategies using parallel or snorkel/chimney (chimney endovascular aneurysm repair [ch-EVAR]) techniques have been developed to address the lack of widespread availability and manufacturing limitations with branched/fenestrated aortic devices for the treatment of complex abdominal aortic aneurysms. Despite high technical success and midterm patency of snorkel stent configurations, concerns remain regarding the perceived increased incidence of early gutter-related type Ia endoleaks. We aimed to evaluate the incidence and natural history of gutter-related type Ia endoleaks following ch-EVAR. Review of medical records and available imaging studies, including completion angiography and serial computed tomographic angiography, was performed for all patients undergoing ch-EVAR at our institution between September 2009 and January 2015. Only procedures involving ≥1 renal artery with or without visceral snorkel stents were included. Primary outcomes of the study were presence and persistence or resolution of early gutter-related type Ia endoleak. Secondary outcomes included aneurysm sac shrinkage and need for secondary intervention related to the presence of type Ia gutter endoleak. Sixty patients (mean age, 75.8 ± 7.6 years; male, 70.0%) underwent ch-EVAR with a total of 111 snorkel stents (97 renal [33 bilateral renal], 12 superior mesenteric artery, 2 celiac). A mean of 1.9 ± 0.6 snorkel stents were placed per patient. Early gutter-related type Ia endoleaks were noted on 30.0% (n = 18) of initial postoperative imaging studies. Follow-up imaging revealed spontaneous resolution of these gutter endoleaks in 44.3%, 65.2%, and 88.4% of patients at 6, 12, and 18 months postprocedure, respectively. Long-term anticoagulation, degree of oversizing, stent type and diameter, and other clinical/anatomic variables were not significantly associated with presence of gutter endoleaks. Two patients (3.3%) required secondary intervention related to persistent gutter endoleak. At a mean radiologic follow-up of 20.9 months, no difference in mean aneurysm sac size change was observed between those with or without early type Ia gutter endoleak (-6.1 ± 10.0 mm vs -4.9 ± 11.5 mm; P = .23). Gutter-related type Ia endoleaks represent a relatively frequent early occurrence after ch-EVAR, but appears to resolve spontaneously in the majority of cases during early to midterm follow-up. Given that few ch-EVAR patients require reintervention related to gutter endoleaks and the presence of such endoleak did not correlate to increased risk for aneurysm sac growth, its natural history may be more benign than originally expected. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Berkeley Supernova Ia Program - I. Observations, data reduction and spectroscopic sample of 582 low-redshift Type Ia supernovae

NASA Astrophysics Data System (ADS)

Silverman, Jeffrey M.; Foley, Ryan J.; Filippenko, Alexei V.; Ganeshalingam, Mohan; Barth, Aaron J.; Chornock, Ryan; Griffith, Christopher V.; Kong, Jason J.; Lee, Nicholas; Leonard, Douglas C.; Matheson, Thomas; Miller, Emily G.; Steele, Thea N.; Barris, Brian J.; Bloom, Joshua S.; Cobb, Bethany E.; Coil, Alison L.; Desroches, Louis-Benoit; Gates, Elinor L.; Ho, Luis C.; Jha, Saurabh W.; Kandrashoff, Michael T.; Li, Weidong; Mandel, Kaisey S.; Modjaz, Maryam; Moore, Matthew R.; Mostardi, Robin E.; Papenkova, Marina S.; Park, Sung; Perley, Daniel A.; Poznanski, Dovi; Reuter, Cassie A.; Scala, James; Serduke, Franklin J. D.; Shields, Joseph C.; Swift, Brandon J.; Tonry, John L.; Van Dyk, Schuyler D.; Wang, Xiaofeng; Wong, Diane S.

2012-09-01

In this first paper in a series, we present 1298 low-redshift (z ≲ 0.2) optical spectra of 582 Type Ia supernovae (SNe Ia) observed from 1989 to 2008 as part of the Berkeley Supernova 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 Å, roughly twice as wide as spectra from most previously published data sets. We present our observing and reduction procedures, and we describe the resulting SN Database, which will be an online, public, searchable data base 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), utilizing our newly constructed set of SNID spectral templates. These templates allow us to accurately classify our entire data set, 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 data set 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. The sheer size of the BSNIP data set and the consistency of our observation and reduction methods make this sample unique among all other published SN Ia data sets and complementary in many ways to the large, low-redshift SN Ia spectra presented by Matheson et al. and Blondin et al. In other BSNIP papers in this series, we use these data to examine the relationships between spectroscopic characteristics and various observables such as photometric and host-galaxy properties.

Grouping normal type Ia supernovae by UV to optical color differences

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milne, Peter A.; Brown, Peter J.; Roming, Peter W. A.

2013-12-10

Observations of many Type Ia supernovae (SNe Ia) for multiple epochs per object with the Swift Ultraviolet Optical Telescope instrument have revealed that there exists order to the differences in the UV-optical colors of optically normal supernovae (SNe). We examine UV-optical color curves for 23 SNe Ia, dividing the SNe into four groups, and find that roughly one-third of 'NUV-blue' SNe Ia have bluer UV-optical colors than the larger 'NUV-red' group. Two minor groups are recognized, 'MUV-blue' and 'irregular' SNe Ia. While we conclude that the latter group is a subset of the NUV-red group, containing the SNe with themore » broadest optical peaks, we conclude that the 'MUV-blue' group is a distinct group. Separating into the groups and accounting for the time evolution of the UV-optical colors lowers the scatter in two NUV-optical colors (e.g., u – v and uvw1 – v) to the level of the scatter in b – v. This finding is promising for extending the cosmological utilization of SNe Ia into the NUV. We generate spectrophotometry of 33 SNe Ia and determine the correct grouping for each. We argue that there is a fundamental spectral difference in the 2900-3500 Å wavelength range, a region suggested to be dominated by absorption from iron-peak elements. The NUV-blue SNe Ia feature less absorption than the NUV-red SNe Ia. We show that all NUV-blue SNe Ia in this sample also show evidence of unburned carbon in optical spectra, whereas only one NUV-red SN Ia features that absorption line. Every NUV-blue event also exhibits a low gradient of the Si II λ6355 absorption feature. Many NUV-red events also exhibit a low gradient, perhaps suggestive that NUV-blue events are a subset of the larger low-velocity gradient group.« less

A luminous, blue progenitor system for the type Iax supernova 2012Z

NASA Astrophysics Data System (ADS)

McCully, Curtis; Jha, Saurabh W.; Foley, Ryan J.; Bildsten, Lars; Fong, Wen-Fai; Kirshner, Robert P.; Marion, G. H.; Riess, Adam G.; Stritzinger, Maximilian D.

2014-08-01

Type Iax supernovae are stellar explosions that are spectroscopically similar to some type Ia supernovae at the time of maximum light emission, except with lower ejecta velocities. They are also distinguished by lower luminosities. At late times, their spectroscopic properties diverge from those of other supernovae, but their composition (dominated by iron-group and intermediate-mass elements) suggests a physical connection to normal type Ia supernovae. Supernovae of type Iax are not rare; they occur at a rate between 5 and 30 per cent of the normal type Ia rate. The leading models for type Iax supernovae are thermonuclear explosions of accreting carbon-oxygen white dwarfs that do not completely unbind the star, implying that they are `less successful' versions of normal type Ia supernovae, where complete stellar disruption is observed. Here we report the detection of the luminous, blue progenitor system of the type Iax SN 2012Z in deep pre-explosion imaging. The progenitor system's luminosity, colours, environment and similarity to the progenitor of the Galactic helium nova V445 Puppis suggest that SN 2012Z was the explosion of a white dwarf accreting material from a helium-star companion. Observations over the next few years, after SN 2012Z has faded, will either confirm this hypothesis or perhaps show that this supernova was actually the explosive death of a massive star.

A luminous, blue progenitor system for the type Iax supernova 2012Z.

PubMed

McCully, Curtis; Jha, Saurabh W; Foley, Ryan J; Bildsten, Lars; Fong, Wen-fai; Kirshner, Robert P; Marion, G H; Riess, Adam G; Stritzinger, Maximilian D

2014-08-07

Type Iax supernovae are stellar explosions that are spectroscopically similar to some type Ia supernovae at the time of maximum light emission, except with lower ejecta velocities. They are also distinguished by lower luminosities. At late times, their spectroscopic properties diverge from those of other supernovae, but their composition (dominated by iron-group and intermediate-mass elements) suggests a physical connection to normal type Ia supernovae. Supernovae of type Iax are not rare; they occur at a rate between 5 and 30 per cent of the normal type Ia rate. The leading models for type Iax supernovae are thermonuclear explosions of accreting carbon-oxygen white dwarfs that do not completely unbind the star, implying that they are 'less successful' versions of normal type Ia supernovae, where complete stellar disruption is observed. Here we report the detection of the luminous, blue progenitor system of the type Iax SN 2012Z in deep pre-explosion imaging. The progenitor system's luminosity, colours, environment and similarity to the progenitor of the Galactic helium nova V445 Puppis suggest that SN 2012Z was the explosion of a white dwarf accreting material from a helium-star companion. Observations over the next few years, after SN 2012Z has faded, will either confirm this hypothesis or perhaps show that this supernova was actually the explosive death of a massive star.

Detection of circumstellar material in a normal type Ia supernova.

PubMed

Patat, F; Chandra, P; Chevalier, R; Justham, S; Podsiadlowski, Ph; Wolf, C; Gal-Yam, A; Pasquini, L; Crawford, I A; Mazzali, P A; Pauldrach, A W A; Nomoto, K; Benetti, S; Cappellaro, E; Elias-Rosa, N; Hillebrandt, W; Leonard, D C; Pastorello, A; Renzini, A; Sabbadin, F; Simon, J D; Turatto, M

2007-08-17

Type Ia supernovae are important cosmological distance indicators. Each of these bright supernovae supposedly results from the thermonuclear explosion of a white dwarf star that, after accreting material from a companion star, exceeds some mass limit, but the true nature of the progenitor star system remains controversial. Here we report the spectroscopic detection of circumstellar material in a normal type Ia supernova explosion. The expansion velocities, densities, and dimensions of the circumstellar envelope indicate that this material was ejected from the progenitor system. In particular, the relatively low expansion velocities suggest that the white dwarf was accreting material from a companion star that was in the red-giant phase at the time of the explosion.

Semi-supervised learning for photometric supernova classification

NASA Astrophysics Data System (ADS)

Richards, Joseph W.; Homrighausen, Darren; Freeman, Peter E.; Schafer, Chad M.; Poznanski, Dovi

2012-01-01

We present a semi-supervised method for photometric supernova typing. Our approach is to first use the non-linear dimension reduction technique diffusion map to detect structure in a data base of supernova light curves and subsequently employ random forest classification on a spectroscopically confirmed training set to learn a model that can predict the type of each newly observed supernova. We demonstrate that this is an effective method for supernova typing. As supernova numbers increase, our semi-supervised method efficiently utilizes this information to improve classification, a property not enjoyed by template-based methods. Applied to supernova data simulated by Kessler et al. to mimic those of the Dark Energy Survey, our methods achieve (cross-validated) 95 per cent Type Ia purity and 87 per cent Type Ia efficiency on the spectroscopic sample, but only 50 per cent Type Ia purity and 50 per cent efficiency on the photometric sample due to their spectroscopic follow-up strategy. To improve the performance on the photometric sample, we search for better spectroscopic follow-up procedures by studying the sensitivity of our machine-learned supernova classification on the specific strategy used to obtain training sets. With a fixed amount of spectroscopic follow-up time, we find that, despite collecting data on a smaller number of supernovae, deeper magnitude-limited spectroscopic surveys are better for producing training sets. For supernova Ia (II-P) typing, we obtain a 44 per cent (1 per cent) increase in purity to 72 per cent (87 per cent) and 30 per cent (162 per cent) increase in efficiency to 65 per cent (84 per cent) of the sample using a 25th (24.5th) magnitude-limited survey instead of the shallower spectroscopic sample used in the original simulations. When redshift information is available, we incorporate it into our analysis using a novel method of altering the diffusion map representation of the supernovae. Incorporating host redshifts leads to a 5 per cent improvement in Type Ia purity and 13 per cent improvement in Type Ia efficiency. A web service for the supernova classification method used in this paper can be found at .

The Implementation of IAS 16 and IAS 41 at Andrew Peller Limited

ERIC Educational Resources Information Center

Lapointe-Antunes, Pascale; Moore, James

2013-01-01

This case asks students to play the role of Doug Grodeckie, Manager of Financial Reporting at Andrew Peller Limited (APL). Doug was asked to prepare a report analyzing Andrew Peller Limited's current tangible long-lived assets disclosures and making recommendations on how best to comply with International Accounting Standard (IAS) 16 Property,…

Binary Paths to Type Ia Supernovae Explosions: the Highlights

NASA Astrophysics Data System (ADS)

Ferrario, Lilia

2013-01-01

This symposium was focused on the hunt for the progenitors of Type Ia supernovae (SNe Ia). Is there a main channel for the production of SNe Ia? If so, are these elusive progenitors single degenerate or double degenerate systems? Although most participants seemed to favor the single degenerate channel, there was no general agreement on the type of binary system at play. An observational puzzle that was highlighted was the apparent paucity of supersoft sources in our Galaxy and also in external galaxies. The single degenerate channel (and as it was pointed out, quite possibly also the double degenerate channel) requires the binary system to pass through a phase of steady nuclear burning. However, the observed number of supersoft sources falls short by a factor of up to 100 in explaining the estimated birth rates of SNe Ia. Thus, are these supersoft sources somehow hidden away and radiating at different wavelengths, or are we missing some important pieces of this puzzle that may lead to the elimination of a certain class of progenitor? Another unanswered question concerns the dependence of SNe Ia luminosities on the age of their host galaxy. Several hypotheses were put forward, but none was singled out as the most likely explanation. It is fair to say that at the end of the symposium the definitive answer to the vexed progenitor question remained well and truly wide open.

Conceptual Issues Concerning Internet Addiction and Internet Gaming Disorder: Further Critique on Ryding and Kaye (2017).

PubMed

Griffiths, Mark D

2018-01-01

The recent commentary paper by Ryding and Kaye Journal of Mental Health and Addictio n (doi 10.1007/s11469-017-9811-6, 2017) rightly claimed that "internet addiction" (IA) is a conceptual minefield and raised some important issues for researchers and treatment providers working in the online addiction field. In the present commentary paper, some of the assertions made by Ryding and Kaye are briefly critiqued and extended. More specifically, the present paper (i) examines IA and Internet-based addictions and argues that IA is now a misnomer, (ii) examines IA and its relationship to Internet Gaming Disorder (IGD) and argues IA and IGD are two completely different constructs, and that IGD is a sub-type of gaming disorder rather than a sub-type of IA, (iii) argues that the time spent engaging in online activities is not a good criterion for assessing online addictions and that the context of use is far more important criterion, and (iv) argues that those researchers working in the IA field can learn a lot from the problem gambling field in collecting robust data. More specifically, one of the innovative ways forward could be to build strategic partnerships with commercial online companies to analyze their behavioral tracking data.

SN~2012cg: Evidence for Interaction Between a Normal Type Ia Supernova and a Non-degenerate Binary Companion

NASA Astrophysics Data System (ADS)

Marion, G. H.; Brown, Peter J.; Vinkó, Jozsef; Silverman, Jeffrey M.; Sand, David J.; Challis, Peter; Kirshner, Robert P.; Wheeler, J. Craig; Berlind, Perry; Brown, Warren R.; Calkins, Michael L.; Camacho, Yssavo; Dhungana, Govinda; Foley, Ryan J.; Friedman, Andrew S.; Graham, Melissa L.; Howell, D. Andrew; Hsiao, Eric Y.; Irwin, Jonathan M.; Jha, Saurabh W.; Kehoe, Robert; Macri, Lucas M.; Maeda, Keiichi; Mandel, Kaisey; McCully, Curtis; Pandya, Viraj; Rines, Kenneth J.; Wilhelmy, Steven; Zheng, Weikang

2016-04-01

We report evidence for excess blue light from the Type Ia supernova (Sn Ia) SN 2012cg at 15 and 16 days before maximum B-band brightness. The emission is consistent with predictions for the impact of the supernova on a non-degenerate binary companion. This is the first evidence for emission from a companion to a normal SN Ia. Sixteen days before maximum light, the B-V color of SN 2012cg is 0.2 mag bluer than for other normal SN Ia. At later times, this supernova has a typical SN Ia light curve, with extinction-corrected {M}B=-19.62+/- 0.02 mag and {{Δ }}{m}15(B)=0.86+/- 0.02. Our data set is extensive, with photometry in seven filters from five independent sources. Early spectra also show the effects of blue light, and high-velocity features are observed at early times. Near maximum, the spectra are normal with a silicon velocity vSi = -10,500 km s-1. Comparing the early data with models by Kasen favors a main-sequence companion of about six solar masses. It is possible that many other SN Ia have main-sequence companions that have eluded detection because the emission from the impact is fleeting and faint.

Arsenic induces diabetic effects through beta-cell dysfunction and increased gluconeogenesis in mice

PubMed Central

Liu, Su; Guo, Xuechao; Wu, Bing; Yu, Haiyan; Zhang, Xuxiang; Li, Mei

2014-01-01

Arsenic as a potential risk factor for type 2 diabetes has been received attention recently. However, the roles of arsenic on development of diabetes are unclear. In this study, we compared the influences of inorganic arsenic (iAs) on normal and diabetic mice by systems toxicology approaches. Although iAs exposure did not change glucose tolerance in normal mice, it caused the pancreatic β-cell dysfunction and increased gluconeogenesis and oxidative damages in liver. However, iAs exposure worsened the glucose tolerance in diabetic mice, which might be due to increased gluconeogenesis and impairment of pancreatic β-cell function. It is interesting that iAs exposure could improve the insulin sensitivity based on the insulin tolerance testing by the activation of glucose uptake-related genes and enzymes in normal and diabetic individuals. Our data suggested that iAs exposure could cause pre-diabetic effects by altering the lipid metabolism, gluconeogenesis and insulin secretion in normal individual, and worsen diabetic effects in diabetes individual by these processes. Insulin resistance might be not the reason of diabetic effects caused by iAs, indicating that mechanism of the diabetogenic effects of iAs exposure is different from the mechanism associated with traditional risk factors (such as obesity)-reduced type 2 diabetes. PMID:25367288

Rescue administration of a helper-dependent adenovirus vector with long-term efficacy in dogs with glycogen storage disease type Ia.

PubMed

Crane, B; Luo, X; Demaster, A; Williams, K D; Kozink, D M; Zhang, P; Brown, T T; Pinto, C R; Oka, K; Sun, F; Jackson, M W; Chan, L; Koeberl, D D

2012-04-01

Glycogen storage disease type Ia (GSD-Ia) stems from glucose-6-phosphatase (G6Pase) deficiency and causes hypoglycemia, hepatomegaly, hypercholesterolemia and lactic acidemia. Three dogs with GSD-Ia were initially treated with a helper-dependent adenovirus encoding a human G6Pase transgene (HDAd-cG6Pase serotype 5) on postnatal day 3. Unlike untreated dogs with GSD-Ia, all three dogs initially maintained normal blood glucose levels. After 6-22 months, vector-treated dogs developed hypoglycemia, anorexia and lethargy, suggesting that the HDAd-cG6Pase serotype 5 vector had lost efficacy. Liver biopsies collected at this time revealed significantly elevated hepatic G6Pase activity and reduced glycogen content, when compared with affected dogs treated only by frequent feeding. Subsequently, the HDAd-cG6Pase serotype 2 vector was administered to two dogs, and hypoglycemia was reversed; however, renal dysfunction and recurrent hypoglycemia complicated their management. Administration of a serotype 2 HDAd vector prolonged survival in one GSD-Ia dog to 12 months of age and 36 months of age in the other, but the persistence of long-term complications limited HDAd vectors in the canine model for GSD-Ia.

Arsenic induces diabetic effects through beta-cell dysfunction and increased gluconeogenesis in mice

NASA Astrophysics Data System (ADS)

Liu, Su; Guo, Xuechao; Wu, Bing; Yu, Haiyan; Zhang, Xuxiang; Li, Mei

2014-11-01

Arsenic as a potential risk factor for type 2 diabetes has been received attention recently. However, the roles of arsenic on development of diabetes are unclear. In this study, we compared the influences of inorganic arsenic (iAs) on normal and diabetic mice by systems toxicology approaches. Although iAs exposure did not change glucose tolerance in normal mice, it caused the pancreatic β-cell dysfunction and increased gluconeogenesis and oxidative damages in liver. However, iAs exposure worsened the glucose tolerance in diabetic mice, which might be due to increased gluconeogenesis and impairment of pancreatic β-cell function. It is interesting that iAs exposure could improve the insulin sensitivity based on the insulin tolerance testing by the activation of glucose uptake-related genes and enzymes in normal and diabetic individuals. Our data suggested that iAs exposure could cause pre-diabetic effects by altering the lipid metabolism, gluconeogenesis and insulin secretion in normal individual, and worsen diabetic effects in diabetes individual by these processes. Insulin resistance might be not the reason of diabetic effects caused by iAs, indicating that mechanism of the diabetogenic effects of iAs exposure is different from the mechanism associated with traditional risk factors (such as obesity)-reduced type 2 diabetes.

Arsenic induces diabetic effects through beta-cell dysfunction and increased gluconeogenesis in mice.

PubMed

Liu, Su; Guo, Xuechao; Wu, Bing; Yu, Haiyan; Zhang, Xuxiang; Li, Mei

2014-11-04

Arsenic as a potential risk factor for type 2 diabetes has been received attention recently. However, the roles of arsenic on development of diabetes are unclear. In this study, we compared the influences of inorganic arsenic (iAs) on normal and diabetic mice by systems toxicology approaches. Although iAs exposure did not change glucose tolerance in normal mice, it caused the pancreatic β-cell dysfunction and increased gluconeogenesis and oxidative damages in liver. However, iAs exposure worsened the glucose tolerance in diabetic mice, which might be due to increased gluconeogenesis and impairment of pancreatic β-cell function. It is interesting that iAs exposure could improve the insulin sensitivity based on the insulin tolerance testing by the activation of glucose uptake-related genes and enzymes in normal and diabetic individuals. Our data suggested that iAs exposure could cause pre-diabetic effects by altering the lipid metabolism, gluconeogenesis and insulin secretion in normal individual, and worsen diabetic effects in diabetes individual by these processes. Insulin resistance might be not the reason of diabetic effects caused by iAs, indicating that mechanism of the diabetogenic effects of iAs exposure is different from the mechanism associated with traditional risk factors (such as obesity)-reduced type 2 diabetes.

Near-Infrared Spectra of Type Ia Supernovae

NASA Technical Reports Server (NTRS)

Marion, G. H.; Hoeflich, P.; Vacca, W. D.; Wheeler, J. C.

2003-01-01

We report near-infrared (NIR) spectroscopic observations of 12 'branch-normal' Type Ia supernovae (SNe Ia) that cover the wavelength region from 0.8 to 2.5 microns. Our sample more than doubles the number of SNe Ia with published NIR spectra within 3 weeks of maximum light. The epochs of observation range from 13 days before maximum light to 18 days after maximum light. A detailed model for a Type Ia supernovae is used to identify spectral features. The Doppler shifts of lines are measured to obtain the velocity and thus the radial distribution of elements. The NIR is an extremely useful tool to probe the chemical structure in the layers of SNe Ia ejecta. This wavelength region is optimal for examining certain products of the SNe Ia explosion that may be blended or obscured in other spectral regions. We identify spectral features from Mg II, Ca II, Si II, Fe II, Co II, Ni II, and possibly Mn II. We find no indications for hydrogen, helium, or carbon in the spectra. The spectral features reveal important clues about the physical characteristics of SNe Ia. We use the features to derive upper limits for the amount of unburned matter, to identify the transition regions from explosive carbon to oxygen burning and from partial to complete silicon burning, and to estimate the level of mixing during and after the explosion. Elements synthesized in the outer layers during the explosion appear to remain in distinct layers. That provides strong evidence for the presence of a detonation phase during the explosion as it occurs in delayed detonation or merger models. Mg II velocities are found to exceed 11,000 - 15,000 km/s, depending on the individual SNe Ia. That result suggests that burning during the explosion reaches the outermost layers of the progenitor and limits the amount of unburned material to less than 10% of the mass of the progenitor. Small residuals of unburned material are predicted by delayed detonation models but are inconsistent with pure deflagration or merger models. Differences in the spectra of the individual SNe Ia demonstrate the variety of these events.

Type Ia supernova rate measurements to redshift 2.5 from CANDELS: Searching for prompt explosions in the early universe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodney, Steven A.; Riess, Adam G.; Graur, Or

2014-07-01

The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) was a multi-cycle treasury program on the Hubble Space Telescope (HST) that surveyed a total area of ∼0.25 deg{sup 2} with ∼900 HST orbits spread across five fields over three years. Within these survey images we discovered 65 supernovae (SNe) of all types, out to z ∼ 2.5. We classify ∼24 of these as Type Ia SNe (SNe Ia) based on host galaxy redshifts and SN photometry (supplemented by grism spectroscopy of six SNe). Here we present a measurement of the volumetric SN Ia rate as a function of redshift, reachingmore » for the first time beyond z = 2 and putting new constraints on SN Ia progenitor models. Our highest redshift bin includes detections of SNe that exploded when the universe was only ∼3 Gyr old and near the peak of the cosmic star formation history. This gives the CANDELS high redshift sample unique leverage for evaluating the fraction of SNe Ia that explode promptly after formation (<500 Myr). Combining the CANDELS rates with all available SN Ia rate measurements in the literature we find that this prompt SN Ia fraction is f{sub P} = 0.53{sub stat0.10}{sup ±0.09}{sub sys0.26}{sup ±0.10}, consistent with a delay time distribution that follows a simple t {sup –1} power law for all times t > 40 Myr. However, mild tension is apparent between ground-based low-z surveys and space-based high-z surveys. In both CANDELS and the sister HST program CLASH (Cluster Lensing And Supernova Survey with Hubble), we find a low rate of SNe Ia at z > 1. This could be a hint that prompt progenitors are in fact relatively rare, accounting for only 20% of all SN Ia explosions—though further analysis and larger samples will be needed to examine that suggestion.« less

Humoral Responses to Islet Antigen-2 and Zinc Transporter 8 Are Attenuated in Patients Carrying HLA-A*24 Alleles at the Onset of Type 1 Diabetes

PubMed Central

Long, Anna E.; Gillespie, Kathleen M.; Aitken, Rachel J.; Goode, Julia C.; Bingley, Polly J.; Williams, Alistair J.K.

2013-01-01

The HLA-A*24 allele has shown negative associations with autoantibodies to islet antigen-2 (IA-2) and zinc transporter 8 (ZnT8) in patients with established type 1 diabetes. Understanding how this HLA class I allele affects humoral islet autoimmunity gives new insights into disease pathogenesis. We therefore investigated the epitope specificity of associations between HLA-A*24 and islet autoantibodies at disease onset. HLA-A*24 genotype and autoantibody responses to insulin (IAA), glutamate decarboxylase (GADA), IA-2, IA-2β, and ZnT8 were analyzed in samples collected from patients with recent-onset type 1 diabetes. After correction for age, sex, and HLA class II genotype, HLA-A*24 was shown to be a negative determinant of IA-2A and ZnT8A. These effects were epitope specific. Antibodies targeting the protein tyrosine phosphatase domains of IA-2 and IA-2β, but not the IA-2 juxtamembrane region, were less common in patients carrying HLA-A*24 alleles. The prevalence of ZnT8A specific or cross-reactive with the ZnT8 tryptophan-325 polymorphic residue, but not those specific to arginine-325, was reduced in HLA-A*24-positive patients. No associations were found between HLA-A*24 and IAA or GADA. Association of an HLA class I susceptibility allele with altered islet autoantibody phenotype at diagnosis suggests CD8 T-cell and/or natural killer cell–mediated killing modulates humoral autoimmune responses. PMID:23396399

Observational Evidence for High Neutronization in Supernova Remnants: Implications for Type Ia Supernova Progenitors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martínez-Rodríguez, Héctor; Badenes, Carles; Andrews, Brett

The physical process whereby a carbon–oxygen white dwarf explodes as a Type Ia supernova (SN Ia) remains highly uncertain. The degree of neutronization in SN Ia ejecta holds clues to this process because it depends on the mass and the metallicity of the stellar progenitor, and on the thermodynamic history prior to the explosion. We report on a new method to determine ejecta neutronization using Ca and S lines in the X-ray spectra of Type Ia supernova remnants (SNRs). Applying this method to Suzaku data of Tycho, Kepler , 3C 397, and G337.2−0.7 in the Milky Way, and N103B inmore » the Large Magellanic Cloud, we find that the neutronization of the ejecta in N103B is comparable to that of Tycho and Kepler , which suggests that progenitor metallicity is not the only source of neutronization in SNe Ia. We then use a grid of SN Ia explosion models to infer the metallicities of the stellar progenitors of our SNRs. The implied metallicities of 3C 397, G337.2−0.7, and N103B are major outliers compared to the local stellar metallicity distribution functions, indicating that progenitor metallicity can be ruled out as the origin of neutronization for these SNRs. Although the relationship between ejecta neutronization and equivalent progenitor metallicity is subject to uncertainties stemming from the {sup 12}C + {sup 16}O reaction rate, which affects the Ca/S mass ratio, our main results are not sensitive to these details.« less

Precise Time Delays from Strongly Gravitationally Lensed Type Ia Supernovae with Chromatically Microlensed Images

NASA Astrophysics Data System (ADS)

Goldstein, Daniel A.; Nugent, Peter E.; Kasen, Daniel N.; Collett, Thomas E.

2018-03-01

Time delays between the multiple images of strongly gravitationally lensed Type Ia supernovae (glSNe Ia) have the potential to deliver precise cosmological constraints, but the effects of microlensing on time delay extraction have not been studied in detail. Here we quantify the effect of microlensing on the glSN Ia yield of the Large Synoptic Survey Telescope (LSST) and the effect of microlensing on the precision and accuracy of time delays that can be extracted from LSST glSNe Ia. Microlensing has a negligible effect on the LSST glSN Ia yield, but it can be increased by a factor of ∼2 over previous predictions to 930 systems using a novel photometric identification technique based on spectral template fitting. Crucially, the microlensing of glSNe Ia is achromatic until three rest-frame weeks after the explosion, making the early-time color curves microlensing-insensitive time delay indicators. By fitting simulated flux and color observations of microlensed glSNe Ia with their underlying, unlensed spectral templates, we forecast the distribution of absolute time delay error due to microlensing for LSST, which is unbiased at the sub-percent level and peaked at 1% for color curve observations in the achromatic phase, while for light-curve observations it is comparable to state-of-the-art mass modeling uncertainties (4%). About 70% of LSST glSN Ia images should be discovered during the achromatic phase, indicating that microlensing time delay uncertainties can be minimized if prompt multicolor follow-up observations are obtained. Accounting for microlensing, the 1–2 day time delay on the recently discovered glSN Ia iPTF16geu can be measured to 40% precision, limiting its cosmological utility.

Precise Time Delays from Strongly Gravitationally Lensed Type Ia Supernovae with Chromatically Microlensed Images

DOE PAGES

Goldstein, Daniel A.; Nugent, Peter E.; Kasen, Daniel N.; ...

2018-03-01

Time delays between the multiple images of strongly gravitationally lensed Type Ia supernovae (glSNe Ia) have the potential to deliver precise cosmological constraints, but the effects of microlensing on time delay extraction have not been studied in detail. Here we quantify the effect of microlensing on the glSN Ia yield of the Large Synoptic Survey Telescope (LSST) and the effect of microlensing on the precision and accuracy of time delays that can be extracted from LSST glSNe Ia. Microlensing has a negligible effect on the LSST glSN Ia yield, but it can be increased by a factor of ~2 overmore » previous predictions to 930 systems using a novel photometric identification technique based on spectral template fitting. Crucially, the microlensing of glSNe Ia is achromatic until three rest-frame weeks after the explosion, making the early-time color curves microlensing-insensitive time delay indicators. By fitting simulated flux and color observations of microlensed glSNe Ia with their underlying, unlensed spectral templates, we forecast the distribution of absolute time delay error due to microlensing for LSST, which is unbiased at the sub-percent level and peaked at 1% for color curve observations in the achromatic phase, while for light-curve observations it is comparable to state-of-the-art mass modeling uncertainties (4%). About 70% of LSST glSN Ia images should be discovered during the achromatic phase, indicating that microlensing time delay uncertainties can be minimized if prompt multicolor follow-up observations are obtained. Lastly, accounting for microlensing, the 1-2 day time delay on the recently discovered glSN Ia iPTF16geu can be measured to 40% precision, limiting its cosmological utility.« less

Precise Time Delays from Strongly Gravitationally Lensed Type Ia Supernovae with Chromatically Microlensed Images

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldstein, Daniel A.; Nugent, Peter E.; Kasen, Daniel N.

Time delays between the multiple images of strongly gravitationally lensed Type Ia supernovae (glSNe Ia) have the potential to deliver precise cosmological constraints, but the effects of microlensing on time delay extraction have not been studied in detail. Here we quantify the effect of microlensing on the glSN Ia yield of the Large Synoptic Survey Telescope (LSST) and the effect of microlensing on the precision and accuracy of time delays that can be extracted from LSST glSNe Ia. Microlensing has a negligible effect on the LSST glSN Ia yield, but it can be increased by a factor of ~2 overmore » previous predictions to 930 systems using a novel photometric identification technique based on spectral template fitting. Crucially, the microlensing of glSNe Ia is achromatic until three rest-frame weeks after the explosion, making the early-time color curves microlensing-insensitive time delay indicators. By fitting simulated flux and color observations of microlensed glSNe Ia with their underlying, unlensed spectral templates, we forecast the distribution of absolute time delay error due to microlensing for LSST, which is unbiased at the sub-percent level and peaked at 1% for color curve observations in the achromatic phase, while for light-curve observations it is comparable to state-of-the-art mass modeling uncertainties (4%). About 70% of LSST glSN Ia images should be discovered during the achromatic phase, indicating that microlensing time delay uncertainties can be minimized if prompt multicolor follow-up observations are obtained. Lastly, accounting for microlensing, the 1-2 day time delay on the recently discovered glSN Ia iPTF16geu can be measured to 40% precision, limiting its cosmological utility.« less

The progenitors of Type Ia supernovae with long delay times

NASA Astrophysics Data System (ADS)

Wang, Bo; Li, Xiang-Dong; Han, Zhan-Wen

2010-02-01

The nature of the progenitors of Type Ia supernovae (SNe Ia) is still unclear. In this paper, by considering the effect of the instability of accretion disc on the evolution of white dwarf (WD) binaries, we performed binary evolution calculations for about 2400 close WD binaries, in which a carbon-oxygen WD accretes material from a main-sequence (MS) star or a slightly evolved subgiant star (WD + MS channel), or a red-giant star (WD + RG channel) to increase its mass to the Chandrasekhar (Ch) mass limit. According to these calculations, we mapped out the initial parameters for SNe Ia in the orbital period-secondary mass (logPi - Mi2) plane for various WD masses for these two channels, respectively. We confirm that WDs in the WD + MS channel with a mass as low as 0.61Msolar can accrete efficiently and reach the Ch limit, while the lowest WD mass for the WD + RG channel is 1.0Msolar. We have implemented these results in a binary population synthesis study to obtain the SN Ia birthrates and the evolution of SN Ia birthrates with time for both a constant star formation rate and a single starburst. We find that the Galactic SN Ia birthrate from the WD + MS channel is ~1.8 × 10-3yr-1 according to our standard model, which is higher than the previous results. However, similar to the previous studies, the birthrate from the WD + RG channel is still low (~3 × 10-5yr-1). We also find that about one-third of SNe Ia from the WD + MS channel and all SNe Ia from the WD + RG channel can contribute to the old populations (>~1Gyr) of SN Ia progenitors.

BmprIa is required in mesenchymal tissue and has limited redundant function with BmprIb in tooth and palate development

PubMed Central

Li, Lu; Lin, Minkui; Wang, Ying; Cserjesi, Peter; Chen, Zhi; Chen, YiPing

2010-01-01

The BMP signaling plays a pivotal role in the development of craniofacial organs, including the tooth and palate. BmprIa and BmprIb encode two type I BMP receptors that are primarily responsible for BMP signaling transduction. We investigated mesenchymal tissue-specific requirement of BmprIa and its functional redundancy with BmprIb during the development of mouse tooth and palate. BmprIa and BmprIb exhibit partially overlapping and distinct expression patterns in the developing tooth and palatal shelf. Neural crest specific inactivation of BmprIa leads to formation of an unusual type of anterior clefting of the secondary palate, an arrest of tooth development at the bud/early cap stages, and severe hypoplasia of the mandible. Defective tooth and palate development is accompanied by the down-regulation of BMP responsive genes and reduced cell proliferation levels in the palatal and dental mesenchyme. To determine if BmprIb could substitute for BmprIa during tooth and palate development, we expressed a constitutively active form of BmprIb (caBmprIb) in the neural crest cells in which BmprIa was simultaneously inactivated. We found that substitution of BmprIa by caBmprIb in neural rest cells rescues the development of molars and maxillary incisor, but the rescued teeth exhibit a delayed odontoblast and ameloblast differentiation. In contrast, caBmprIb fails to rescue the palatal and mandibular defects including the lack of lower incisors. Our results demonstrate an essential role for BmprIa in the mesenchymal component and a limited functional redundancy between BmprIa and BmprIb in a tissue specific manner during tooth and palate development. PMID:21034733

A Chandrasekhar Mass Progenitor for the Type Ia Supernova Remnant 3C 397 from the Enhanced Abundances of Nickel and Manganese

NASA Technical Reports Server (NTRS)

Yamaguchi, Hiroya; Badenes, Carles; Foster, Adam R.; Bravo, Eduardo; Williams, Brian J.; Maeda, Keiichi; Nobukawa, Masayoshi; Eriksen, Kristoffer A.; Brickhouse, Nancy S.; Petre, Robert;

Enhanced interoceptive awareness during anticipation of public speaking is associated with fear of negative evaluation.

PubMed

Durlik, Caroline; Brown, Gary; Tsakiris, Manos

2014-04-01

Interoceptive awareness (IA)--the ability to detect internal body signals--has been linked to various aspects of emotional processing. However, it has been examined mostly as a trait variable, with few studies also investigating state dependent fluctuations in IA. Based on the known positive correlation between IA and emotional reactivity, negative affectivity, and trait anxiety, the current study examined whether IA, as indexed by heartbeat detection accuracy, would change during an anxiety-provoking situation. Participants in the experimental condition, in which they anticipated giving a speech in front of a small audience, displayed significant IA increases from baseline to anticipation. Enhancement in IA was positively correlated with fear of negative evaluation. Implications of the results are discussed in relation to the role of trait and state IA in emotional experience.

Child abuse and neglect in institutional settings, cumulative lifetime traumatization, and psychopathological long-term correlates in adult survivors: The Vienna Institutional Abuse Study.

PubMed

Lueger-Schuster, Brigitte; Knefel, Matthias; Glück, Tobias M; Jagsch, Reinhold; Kantor, Viktoria; Weindl, Dina

2018-02-01

Child maltreatment (CM) in foster care settings (i.e., institutional abuse, IA) is known to have negative effects on adult survivor's mental health. This study examines and compares the extent of CM (physical, emotional, and sexual abuse; physical and emotional neglect) and lifetime traumatization with regard to current adult mental health in a group of survivors of IA and a comparison group from the community. Participants in the foster care group (n = 220) were adult survivors of IA in Viennese foster care institutions, the comparison group (n = 234) consisted of persons from the Viennese population. The comparison group included persons who were exposed to CM within their families. Participants completed the Childhood Trauma Questionnaire, the Life Events Checklist for DSM-5, the PTSD Checklist for DSM-5, the International Trauma Questionnaire for ICD-11, and the Brief Symptom Inventory-18 and completed a structured clinical interview. Participants in the foster care group showed higher scores in all types of CM than the comparison group and 57.7% reported exposure to all types of CM. The foster care group had significantly higher prevalence rates in almost all mental disorders including personality disorders and suffered from higher symptom distress in all dimensional measures of psychopathology including depression, anxiety, somatization, dissociation, and the symptom dimensions of PTSD. In both groups, adult life events and some but not all forms of CM predicted PTSD and adult life events partly mediated the association of PTSD and CM. Explanations for the severe consequences of CM and IA are discussed. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Identification of genes encoding the type IX secretion system and secreted proteins in Flavobacterium columnare IA-S-4

USDA-ARS?s Scientific Manuscript database

Flavobacterium columnare, a member of the phylum Bacteroidetes, causes columnaris disease in wild and aquaculture-reared freshwater fish. The mechanisms responsible for columnaris disease are not known. Many members of the phylum Bacteroidetes use type IX secretion systems (T9SSs) to secrete enzymes...

Spectroscopic Classification of ASASSN-15rm as a Type Ia Supernova

NASA Astrophysics Data System (ADS)

Zheng, W.; Halevi, G.; Shivvers, I.; Yuk, H.; Filippenko, A. V.

2015-10-01

We report that inspection of a CCD spectrum (range 350-1050 nm) of ASASSN-15rm (ATel #8192), obtained on Oct. 20.50 UT with the Shane 3-m reflector (+ Kast spectrograph) at Lick Observatory, shows that the object is a normal Type Ia supernova roughly 1 week past maximum brightness.

Renal endoplasmic reticulum stress is coupled to impaired autophagy in a mouse model of GSD Ia.

PubMed

Farah, Benjamin L; Landau, Dustin J; Wu, Yajun; Sinha, Rohit A; Loh, Alwin; Bay, Boon-Huat; Koeberl, Dwight D; Yen, Paul M

2017-11-01

GSD Ia (von Gierke Disease, Glycogen Storage Disease Type Ia) is a devastating genetic disorder with long-term sequelae, such as non-alcoholic fatty liver disease and renal failure. Down-regulated autophagy is involved in the development of hepatic metabolic dysfunction in GSD Ia; however, the role of autophagy in the renal pathology is unknown. Here we show that autophagy is impaired and endoplasmic reticulum (ER) stress is increased in the kidneys of a mouse model of GSD Ia. Induction of autophagy by rapamycin also reduces this ER stress. Taken together, these results show an additional role for autophagy down-regulation in the pathogenesis of GSD Ia, and provide further justification for the use of autophagy modulators in GSD Ia. Copyright © 2017 Elsevier Inc. All rights reserved.

The Association of Arsenic Exposure and Metabolism With Type 1 and Type 2 Diabetes in Youth: The SEARCH Case-Control Study

PubMed Central

Kuo, Chin-Chi; Spratlen, Miranda; Thayer, Kristina A.; Mendez, Michelle A.; Hamman, Richard F.; Dabelea, Dana; Adgate, John L.; Knowler, William C.; Bell, Ronny A.; Miller, Frederick W.; Liese, Angela D.; Zhang, Chongben; Douillet, Christelle; Drobná, Zuzana; Mayer-Davis, Elizabeth J.; Styblo, Miroslav

2017-01-01

OBJECTIVE Little is known about arsenic and diabetes in youth. We examined the association of arsenic with type 1 and type 2 diabetes in the SEARCH for Diabetes in Youth Case-Control (SEARCH-CC) study. Because one-carbon metabolism can influence arsenic metabolism, we also evaluated the potential interaction of folate and vitamin B12 with arsenic metabolism on the odds of diabetes. RESEARCH DESIGN AND METHODS Six hundred eighty-eight participants <22 years of age (429 with type 1 diabetes, 85 with type 2 diabetes, and 174 control participants) were evaluated. Arsenic species (inorganic arsenic [iAs], monomethylated arsenic [MMA], dimethylated arsenic [DMA]), and one-carbon metabolism biomarkers (folate and vitamin B12) were measured in plasma. We used the sum of iAs, MMA, and DMA (∑As) and the individual species as biomarkers of arsenic concentrations and the relative proportions of the species over their sum (iAs%, MMA%, DMA%) as biomarkers of arsenic metabolism. RESULTS Median ∑As, iAs%, MMA%, and DMA% were 83.1 ng/L, 63.4%, 10.3%, and 25.2%, respectively. ∑As was not associated with either type of diabetes. The fully adjusted odds ratios (95% CI), rescaled to compare a difference in levels corresponding to the interquartile range of iAs%, MMA%, and DMA%, were 0.68 (0.50–0.91), 1.33 (1.02–1.74), and 1.28 (1.01–1.63), respectively, for type 1 diabetes and 0.82 (0.48–1.39), 1.09 (0.65–1.82), and 1.17 (0.77–1.77), respectively, for type 2 diabetes. In interaction analysis, the odds ratio of type 1 diabetes by MMA% was 1.80 (1.25–2.58) and 0.98 (0.70–1.38) for participants with plasma folate levels above and below the median (P for interaction = 0.02), respectively. CONCLUSIONS Low iAs% versus high MMA% and DMA% was associated with a higher odds of type 1 diabetes, with a potential interaction by folate levels. These data support further research on the role of arsenic metabolism in type 1 diabetes, including the interplay with one-carbon metabolism biomarkers. PMID:27810988

The Association of Arsenic Exposure and Metabolism With Type 1 and Type 2 Diabetes in Youth: The SEARCH Case-Control Study.

PubMed

Grau-Pérez, Maria; Kuo, Chin-Chi; Spratlen, Miranda; Thayer, Kristina A; Mendez, Michelle A; Hamman, Richard F; Dabelea, Dana; Adgate, John L; Knowler, William C; Bell, Ronny A; Miller, Frederick W; Liese, Angela D; Zhang, Chongben; Douillet, Christelle; Drobná, Zuzana; Mayer-Davis, Elizabeth J; Styblo, Miroslav; Navas-Acien, Ana

2017-01-01

Little is known about arsenic and diabetes in youth. We examined the association of arsenic with type 1 and type 2 diabetes in the SEARCH for Diabetes in Youth Case-Control (SEARCH-CC) study. Because one-carbon metabolism can influence arsenic metabolism, we also evaluated the potential interaction of folate and vitamin B12 with arsenic metabolism on the odds of diabetes. Six hundred eighty-eight participants <22 years of age (429 with type 1 diabetes, 85 with type 2 diabetes, and 174 control participants) were evaluated. Arsenic species (inorganic arsenic [iAs], monomethylated arsenic [MMA], dimethylated arsenic [DMA]), and one-carbon metabolism biomarkers (folate and vitamin B12) were measured in plasma. We used the sum of iAs, MMA, and DMA (∑As) and the individual species as biomarkers of arsenic concentrations and the relative proportions of the species over their sum (iAs%, MMA%, DMA%) as biomarkers of arsenic metabolism. Median ∑As, iAs%, MMA%, and DMA% were 83.1 ng/L, 63.4%, 10.3%, and 25.2%, respectively. ∑As was not associated with either type of diabetes. The fully adjusted odds ratios (95% CI), rescaled to compare a difference in levels corresponding to the interquartile range of iAs%, MMA%, and DMA%, were 0.68 (0.50-0.91), 1.33 (1.02-1.74), and 1.28 (1.01-1.63), respectively, for type 1 diabetes and 0.82 (0.48-1.39), 1.09 (0.65-1.82), and 1.17 (0.77-1.77), respectively, for type 2 diabetes. In interaction analysis, the odds ratio of type 1 diabetes by MMA% was 1.80 (1.25-2.58) and 0.98 (0.70-1.38) for participants with plasma folate levels above and below the median (P for interaction = 0.02), respectively. Low iAs% versus high MMA% and DMA% was associated with a higher odds of type 1 diabetes, with a potential interaction by folate levels. These data support further research on the role of arsenic metabolism in type 1 diabetes, including the interplay with one-carbon metabolism biomarkers. © 2017 by the American Diabetes Association.

Emerging Tick-Borne Disease in African Vipers Caused by a Cowdria-like Organism

DTIC Science & Technology

2006-01-01

display, a currently valid OMS control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE AQDRESS. 1. REPORT DATE (DD-MM- YYYY) 12. REPORT TYPE I Oct... Cause ~ by a Cowdria-like Organism I II 5a. CONTRACT NUMBER N/A 5b. GRANT NUMBER N/A 5c. PROGRAM ELEMENT NUMBER 62202F 6. AUTHOR(S) I... caused by the rIckettSIa orgamsm CowdrIa rumlnantmm, currently Ehr Ichla rummantlUm. It poses an Immment treat to the Western Hemisphere, where it could

The double-degenerate model for the progenitors of Type Ia supernovae

NASA Astrophysics Data System (ADS)

Liu, D.; Wang, B.; Han, Z.

2018-02-01

The double-degenerate (DD) model, involving the merging of massive double carbon-oxygen white dwarfs (CO WDs) driven by gravitational wave radiation, is one of the classical pathways for the formation of Type Ia supernovae (SNe Ia). Recently, it has been proposed that the WD+He subgiant channel has a significant contribution to the production of massive double WDs, in which the primary WD accumulates mass by accreting He-rich matter from an He subgiant. We evolved about 1800 CO WD+He star systems and obtained a large and dense grid for producing SNe Ia through the DD model. We then performed a series of binary population synthesis simulations for the DD model, in which the WD+He subgiant channel is calculated by interpolations in the SN Ia production grid. According to our standard model, the Galactic birth rate of SNe Ia is about 2.4 × 10- 3 yr- 1 for the WD+He subgiant channel of the DD model; the total birth rate is about 3.7 × 10- 3 yr- 1 for all channels, reproducing that of observations. Previous theoretical models still have deficit with the observed SNe Ia with delay times < 1 Gyr and > 8 Gyr. After considering the WD+He subgiant channel, we found that the delay time distributions are comparable with the observed results. Additionally, some recent studies proposed that the violent WD mergers are more likely to produce SNe Ia based on the DD model. We estimated that the violent mergers through the DD model may contribute to at most 16 per cent of all SNe Ia.

A rapid lateral flow immunoassay for the detection of tyrosine phosphatase-like protein IA-2 autoantibodies in human serum.

PubMed

Kikkas, Ingrid; Mallone, Roberto; Larger, Etienne; Volland, Hervé; Morel, Nathalie

2014-01-01

Type 1 diabetes (T1D) results from the destruction of pancreatic insulin-producing beta cells and is strongly associated with the presence of islet autoantibodies. Autoantibodies to tyrosine phosphatase-like protein IA-2 (IA-2As) are considered to be highly predictive markers of T1D. We developed a novel lateral flow immunoassay (LFIA) based on a bridging format for the rapid detection of IA-2As in human serum samples. In this assay, one site of the IA-2As is bound to HA-tagged-IA-2, which is subsequently captured on the anti-HA-Tag antibody-coated test line on the strip. The other site of the IA-2As is bound to biotinylated IA-2, allowing the complex to be visualized using colloidal gold nanoparticle-conjugated streptavidin. For this study, 35 serum samples from T1D patients and 44 control sera from non-diabetic individuals were analyzed with our novel assay and the results were correlated with two IA-2A ELISAs. Among the 35 serum samples from T1D patients, the IA-2A LFIA, the in-house IA-2A ELISA and the commercial IA-2A ELISA identified as positive 21, 29 and 30 IA-2A-positive sera, respectively. The major advantages of the IA-2A LFIA are its rapidity and simplicity.

THE FAST DECLINING TYPE Ia SUPERNOVA 2003gs, AND EVIDENCE FOR A SIGNIFICANT DISPERSION IN NEAR-INFRARED ABSOLUTE MAGNITUDES OF FAST DECLINERS AT MAXIMUM LIGHT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krisciunas, Kevin; Marion, G. H.; Suntzeff, Nicholas B.

2009-12-15

We obtained optical photometry of SN 2003gs on 49 nights, from 2 to 494 days after T(B {sub max}). We also obtained near-IR photometry on 21 nights. SN 2003gs was the first fast declining Type Ia SN that has been well observed since SN 1999by. While it was subluminous in optical bands compared to more slowly declining Type Ia SNe, it was not subluminous at maximum light in the near-IR bands. There appears to be a bimodal distribution in the near-IR absolute magnitudes of Type Ia SNe at maximum light. Those that peak in the near-IR after T(B {sub max})more » are subluminous in the all bands. Those that peak in the near-IR prior to T(B {sub max}), such as SN 2003gs, have effectively the same near-IR absolute magnitudes at maximum light regardless of the decline rate {delta}m {sub 15}(B). Near-IR spectral evidence suggests that opacities in the outer layers of SN 2003gs are reduced much earlier than for normal Type Ia SNe. That may allow {gamma} rays that power the luminosity to escape more rapidly and accelerate the decline rate. This conclusion is consistent with the photometric behavior of SN 2003gs in the IR, which indicates a faster than normal decline from approximately normal peak brightness.« less

Modified Einstein's gravity as a possible missing link between sub- and super-Chandrasekhar type Ia supernovae

NASA Astrophysics Data System (ADS)

Das, Upasana; Mukhopadhyay, Banibrata

2015-05-01

We explore the effect of modification to Einstein's gravity in white dwarfs for the first time in the literature, to the best of our knowledge. This leads to significantly sub- and super-Chandrasekhar limiting masses of white dwarfs, determined by a single model parameter. On the other hand, type Ia supernovae (SNeIa), a key to unravel the evolutionary history of the universe, are believed to be triggered in white dwarfs having mass close to the Chandrasekhar limit. However, observations of several peculiar, under- and over-luminous SNeIa argue for exploding masses widely different from this limit. We argue that explosions of the modified gravity induced sub- and super-Chandrasekhar limiting mass white dwarfs result in under- and over-luminous SNeIa respectively, thus unifying these two apparently disjoint sub-classes and, hence, serving as a missing link. Our discovery raises two fundamental questions. Is the Chandrasekhar limit unique? Is Einstein's gravity the ultimate theory for understanding astronomical phenomena? Both the answers appear to be no!

On the Time Variation of Dust Extinction and Gas Absorption for Type Ia Supernovae Observed through a Nonuniform Interstellar Medium

NASA Astrophysics Data System (ADS)

Huang, X.; Aldering, G.; Biederman, M.; Herger, B.

2017-11-01

For Type Ia supernovae (SNe Ia) observed through a nonuniform interstellar medium (ISM) in its host galaxy, we investigate whether the nonuniformity can cause observable time variations in dust extinction and in gas absorption due to the expansion of the SN photosphere with time. We show that, owing to the steep spectral index of the ISM density power spectrum, sizable density fluctuation amplitudes at the length scale of typical ISM structures (≳ 10 {pc}) will translate to much smaller fluctuations on the scales of an SN photosphere. Therefore, the typical amplitude of time variation due to a nonuniform ISM, of absorption equivalent widths, and of extinction, would be small. As a result, we conclude that nonuniform ISM density should not impact cosmology measurements based on SNe Ia. We apply our predictions based on the ISM density power-law power spectrum to the observations of two highly reddened SNe Ia, SN 2012cu and SN 2014J.

On the Time Variation of Dust Extinction and Gas Absorption for Type Ia Supernovae Observed Through Non-uniform Interstellar Medium

NASA Astrophysics Data System (ADS)

Huang, Xiaosheng; Aldering, Gregory; Biederman, Moriah; Herger, Brendan

2018-01-01

For Type Ia supernovae (SNe Ia) observed through a non-uniform interstellar medium (ISM) in its host galaxy, we investigate whether the non-uniformity can cause observable time variations in dust extinction and in gas absorption due to the expansion of the SN photosphere with time. We show that, owing to the steep spectral index of the ISM density power spectrum, sizable density fluctuation amplitudes at the length scale of typical ISM structures (>~ 10 pc) will translate to much smaller fluctuations on the scales of a SN photosphere. Therefore the typical amplitude of time variation due to non-uniform ISM, of absorption equivalent widths and of extinction, would be small. As a result, we conclude that non-uniform ISM density should not impact cosmology measurements based on SNe Ia. We apply our predictions based on the ISM density power law power spectrum to the observations of two highly reddened SNe Ia, SN 2012cu and SN 2014J.

The Type Ia supernova 1989B in NGC 3627 (M66)

NASA Technical Reports Server (NTRS)

Wells, Lisa A.; Phillips, M. M.; Suntzeff, Nicholas B.; Heathcote, S. R.; Hamuy, Mario; Navarrete, M.; Fernandez, M.; Weller, W. G.; Schommer, R. A.; Kirshner, Robert P.

1994-01-01

We report extensive optical photometry and spectroscopy of the Type Ia supernova 1989B. Maximum light in B occurred approximately seven days after discovery on JD 2447565.3 +/- 1.0 (1989 February 7.8 +/- 1.0) at a magnitude of 12.34 +/- 0.05. The UBV light curves of this supernova were very similar to those of other well observed Type Ia events such as SN 1981B and SN 1980N. From a comparison of the UBVRIJHK photometry, we derive an extinction for SN 1989B of E(B-V) = 0.37 +/- 0.03 mags relative to the unobscured Type Ia SN 1980N. The properties of the dust responsible for the reddening of SN 1989B appear to have been similar to those of normal dust in the Milky Way. In particular, we find no evidence for an unusually low value of the ratio of the total to selective absorption. We derive a distance modulus of delta mu(sub 0) = -1.62 +/- 0.03 mag relative to the Type Ia SN 1980N. We present optical spectra which provide essentially continuous coverage of the spectral evolution of SN 1989B over the first month following B maximum. These data show the transition from the maximum-light spectrum, in which lines of elements such as Ca, Si, S, Mg, and O are most prominent, to the Fe-dominated spectrum observed a few weeks after maximum. This transition occurred quite smoothly over a two-week period following B maximum. Comparison of the spectra of SN 1989B with data for two other well observed Type Ia supernovae -- 1981B and 1986G -- reveals subtle differences in the relative strengths of the S II and Si II absorption lines at maximum light. However, these differences disappeared within a week or so after maximum with the onset of the Fe-dominated phase.

Exogenous Stimulation of Type I Interferon Protects Mice with Chronic Granulomatous Disease from Aspergillosis through Early Recruitment of Host-Protective Neutrophils into the Lung.

PubMed

Seyedmousavi, Seyedmojtaba; Davis, Michael J; Sugui, Janyce A; Pinkhasov, Tzvia; Moyer, Shannon; Salazar, Andres M; Chang, Yun C; Kwon-Chung, Kyung J

2018-03-27

Invasive aspergillosis (IA) remains the primary cause of morbidity and mortality in chronic granulomatous disease (CGD) patients, often due to infection by Aspergillus species refractory to antifungals. This motivates the search for alternative treatments, including immunotherapy. We investigated the effect of exogenous type I interferon (IFN) activation on the outcome of IA caused by three Aspergillus species, A. fumigatus , A. nidulans , and A. tanneri , in CGD mice. The animals were treated with poly(I):poly(C) carboxymethyl cellulose poly-l-lysine (PICLC), a mimetic of double-stranded RNA, 24 h preinfection and postinfection. The survival rates and lung fungal burdens were markedly improved by PICLC immunotherapy in animals infected with any one of the three Aspergillus species. While protection from IA was remarkable, PICLC induction of type I IFN in the lungs surged 24 h posttreatment and returned to baseline levels by 48 h, suggesting that PICLC altered early events in protection against IA. Immunophenotyping of recruited leukocytes and histopathological examination of tissue sections showed that PICLC induced similar cellular infiltrates as those in untreated-infected mice, in both cases dominated by monocytic cells and neutrophils. However, the PICLC immunotherapy resulted in a marked earlier recruitment of the leukocytes. Unlike with conidia, infection with A. nidulans germlings reduced the protective effect of PICLC immunotherapy. Additionally, antibody depletion of neutrophils totally reversed the protection, suggesting that neutrophils are crucial for PICLC-mediated protection. Together, these data show that prophylactic PICLC immunotherapy prerecruits these cells, enabling them to attack the conidia and thus resulting in a profound protection from IA. IMPORTANCE Patients with chronic granulomatous disease (CGD) are highly susceptible to invasive aspergillosis (IA). While Aspergillus fumigatus is the most-studied Aspergillus species, CGD patients often suffer IA caused by A. nidulans , A. tanneri , and other rare species. These non- fumigatus Aspergillus species are more resistant to antifungal drugs and cause higher fatality rates than A. fumigatus Therefore, alternative therapies are needed to protect CGD patients. We report an effective immunotherapy of mice infected with three Aspergillus species via PICLC dosing. While protection from IA was long lasting, PICLC induction of type I IFN surged but quickly returned to baseline levels, suggesting that PICLC was altering early events in IA. Interestingly, we found responding immune cells to be similar between PICLC-treated and untreated-infected mice. However, PICLC immunotherapy resulted in an earlier recruitment of the leukocytes and suppressed fungal growth. This study highlights the value of type I IFN induction in CGD patients.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Conley, A.; Goldhaber, G.; Wang, L.

We present measurements of {Omega}{sub m} and {Omega}{sub {Lambda}} from a blind analysis of 21 high redshift supernovae using a new technique (CMAGIC) for fitting the multicolor lightcurves of Type Ia supernovae, first introduced in Wang et al. (2003). CMAGIC takes advantage of the remarkably simple behavior of Type Ia supernovae on color-magnitude diagrams, and has several advantages over current techniques based on maximum magnitudes. Among these are a reduced sensitivity to host galaxy dust extinction, a shallower luminosity-width relation, and the relative simplicity of the fitting procedure. This allows us to provide a cross check of previous supernova cosmologymore » results, despite the fact that current data sets were not observed in a manner optimized for CMAGIC. We describe the details of our novel blindness procedure, which is designed to prevent experimenter bias. The data are broadly consistent with the picture of an accelerating Universe, and agree with a at Universe within 1.7{sigma}, including systematics. We also compare the CMAGIC results directly with those of a maximum magnitude fit to the same SNe, finding that CMAGIC favors more acceleration at the 1.6{sigma} level, including systematics and the correlation between the two measurements. A fit for w assuming a at Universe yields a value which is consistent with a cosmological constant within 1.2{sigma}.« less

See Change: the Supernova Sample from the Supernova Cosmology Project High Redshift Cluster Supernova Survey

NASA Astrophysics Data System (ADS)

Hayden, Brian; Perlmutter, Saul; Boone, Kyle; Nordin, Jakob; Rubin, David; Lidman, Chris; Deustua, Susana E.; Fruchter, Andrew S.; Aldering, Greg Scott; Brodwin, Mark; Cunha, Carlos E.; Eisenhardt, Peter R.; Gonzalez, Anthony H.; Jee, James; Hildebrandt, Hendrik; Hoekstra, Henk; Santos, Joana; Stanford, S. Adam; Stern, Daniel; Fassbender, Rene; Richard, Johan; Rosati, Piero; Wechsler, Risa H.; Muzzin, Adam; Willis, Jon; Boehringer, Hans; Gladders, Michael; Goobar, Ariel; Amanullah, Rahman; Hook, Isobel; Huterer, Dragan; Huang, Xiaosheng; Kim, Alex G.; Kowalski, Marek; Linder, Eric; Pain, Reynald; Saunders, Clare; Suzuki, Nao; Barbary, Kyle H.; Rykoff, Eli S.; Meyers, Joshua; Spadafora, Anthony L.; Sofiatti, Caroline; Wilson, Gillian; Rozo, Eduardo; Hilton, Matt; Ruiz-Lapuente, Pilar; Luther, Kyle; Yen, Mike; Fagrelius, Parker; Dixon, Samantha; Williams, Steven

2017-01-01

The Supernova Cosmology Project has finished executing a large (174 orbits, cycles 22-23) Hubble Space Telescope program, which has measured ~30 type Ia Supernovae above z~1 in the highest-redshift, most massive galaxy clusters known to date. Our SN Ia sample closely matches our pre-survey predictions; this sample will improve the constraint by a factor of 3 on the Dark Energy equation of state above z~1, allowing an unprecedented probe of Dark Energy time variation. When combined with the improved cluster mass calibration from gravitational lensing provided by the deep WFC3-IR observations of the clusters, See Change will triple the Dark Energy Task Force Figure of Merit. With the primary observing campaign completed, we present the preliminary supernova sample and our path forward to the supernova cosmology results. We also compare the number of SNe Ia discovered in each cluster with our pre-survey expectations based on cluster mass and SFR estimates. Our extensive HST and ground-based campaign has already produced unique results; we have confirmed several of the highest redshift cluster members known to date, confirmed the redshift of one of the most massive galaxy clusters at z~1.2 expected across the entire sky, and characterized one of the most extreme starburst environments yet known in a z~1.7 cluster. We have also discovered a lensed SN Ia at z=2.22 magnified by a factor of ~2.7, which is the highest spectroscopic redshift SN Ia currently known.

The dark energy survey Y1 supernova search: Survey strategy compared to forecasts and the photometric type Is SN volumetric rate

NASA Astrophysics Data System (ADS)

Fischer, John Arthur

For 70 years, the physics community operated under the assumption that the expansion of the Universe must be slowing due to gravitational attraction. Then, in 1998, two teams of scientists used Type Ia supernovae to discover that cosmic expansion was actually acceler- ating due to a mysterious "dark energy." As a result, Type Ia supernovae have become the most cosmologically important transient events in the last 20 years, with a large amount of effort going into their discovery as well as understanding their progenitor systems. One such probe for understanding Type Ia supernovae is to use rate measurements to de- termine the time delay between star formation and supernova explosion. For the last 30 years, the discovery of individual Type Ia supernova events has been accelerating. How- ever, those discoveries were happening in time-domain surveys that probed only a portion of the redshift range where expansion was impacted by dark energy. The Dark Energy Survey (DES) is the first project in the "next generation" of time-domain surveys that will discovery thousands of Type Ia supernovae out to a redshift of 1.2 (where dark energy be- comes subdominant) and DES will have better systematic uncertainties over that redshift range than any survey to date. In order to gauge the discovery effectiveness of this survey, we will use the first season's 469 photometrically typed supernovee and compare it with simulations in order to update the full survey Type Ia projections from 3500 to 2250. We will then use 165 of the 469 supernovae out to a redshift of 0.6 to measure the supernovae rate both as a function of comoving volume and of the star formation rate as it evolves with redshift. We find the most statistically significant prompt fraction of any survey to date (with a 3.9? prompt fraction detection). We will also reinforce the already existing tension in the measurement of the delayed fraction between high (z > 1.2) and low red- shift rate measurements, where we find no significant evidence of a delayed fraction at all in our photometric sample.

TIME VARIATION OF AV AND RV FOR TYPE Ia SUPERNOVAE BEHIND INTERSTELLAR DUST

NASA Astrophysics Data System (ADS)

Huang, Xiaosheng; Biederman, M.; Herger, B.; Aldering, G. S.

2014-01-01

TIME VARIATION OF AV AND RV FOR TYPE Ia SUPERNOVAE BEHIND NON-UNIFORM INTERSTELLAR DUST ABSTRACT We investigate the time variation of the visual extinction, AV, and the total-to-selective extinction ratio, RV, resulting from interstellar dust in front of an expanding photospheric disk of a type Ia supernova (SN Ia). We simulate interstellar dust clouds according to a power law power spectrum and produce extinction maps that either follow a pseudo-Gaussian distribution or a lognormal distribution. The RV maps are produced through a correlation between AV and RV. With maps of AV and RV generated in each case (pseudo-Gaussian and lognormal), we then compute the effective AV and RV for a SN as its photospheric disk expands behind the dust screen. We find for a small percentage of SNe the AV and RV values can vary by a large factor from day to day in the first 40 days after explosion.

Spectral Sequences of Type Ia Supernovae. I. Connecting Normal and Subluminous SNe Ia and the Presence of Unburned Carbon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heringer, E.; Kerkwijk, M. H. van; Sim, S. A.

2017-09-01

Type Ia supernovae (SNe Ia) are generally agreed to arise from thermonuclear explosions of carbon–oxygen white dwarfs. The actual path to explosion, however, remains elusive, with numerous plausible parent systems and explosion mechanisms suggested. Observationally, SNe Ia have multiple subclasses, distinguished by their light curves and spectra. This raises the question of whether these indicate that multiple mechanisms occur in nature or that explosions have a large but continuous range of physical properties. We revisit the idea that normal and 91bg-like SNe can be understood as part of a spectral sequence in which changes in temperature dominate. Specifically, we findmore » that a single ejecta structure is sufficient to provide reasonable fits of both the normal SN Ia SN 2011fe and the 91bg-like SN 2005bl, provided that the luminosity and thus temperature of the ejecta are adjusted appropriately. This suggests that the outer layers of the ejecta are similar, thus providing some support for a common explosion mechanism. Our spectral sequence also helps to shed light on the conditions under which carbon can be detected in premaximum SN Ia spectra—we find that emission from iron can “fill in” the carbon trough in cool SNe Ia. This may indicate that the outer layers of the ejecta of events in which carbon is detected are relatively metal-poor compared to events in which carbon is not detected.« less

Persistent structural adaptation in the lungs of guinea pigs raised at high altitude.

PubMed

Ravikumar, Priya; Bellotto, Dennis J; Hsia, Connie C W

2015-03-01

Laboratory guinea pigs raised at high altitude (HA, 3800 m) for up to 6 mo exhibit enhanced alveolar growth and remodeling (Hsia et al., 2005. Resp. Physiol. Neurobiol. 147, 105-115). To determine whether initial HA-induced structural enhancement persists following return to intermediate altitude (IA), we raised weanling guinea pigs at (a) HA for 11-12 mo, (b) IA (1200 m) for 11-12 mo, and (c) HA for 4 mo followed by IA for 7-8 mo (HA-to-IA). Morphometric analysis was performed under light and electron microscopy. Body weight and lung volume were similar among groups. Prolonged HA residence increased alveolar epithelium and interstitium volumes while reducing alveolar-capillary blood volume. The HA-induced gains in type-1 epithelium volume and alveolar surface area were no longer present following return to IA whereas volume increases in type-2 epithelium and interstitium and the reduction in alveolar duct volume persisted. Results demonstrate persistent augmentation of some but not all aspects of lung structure throughout prolonged HA residence, with partial reversibility following re-acclimatization to IA. Copyright © 2014 Elsevier B.V. All rights reserved.

The type Ia supernova SNLS-03D3bb from a super-Chandrasekhar-masswhite dwarf star

DOE Office of Scientific and Technical Information (OSTI.GOV)

Howell, D.Andrew; Sullivan, Mark; Nugent, Peter E.

2006-02-01

The acceleration of the expansion of the universe, and theneed for Dark Energy, were inferred from the observations of Type Iasupernovae (SNe Ia) 1;2. There is consensus that SNeIa are thermonuclearexplosions that destroy carbon-oxygen white dwarf stars that accretematter from a companion star3, although the nature of this companionremains uncertain. SNe Ia are thought to be reliable distance indicatorsbecause they have a standard amount of fuel and a uniform trigger theyare predicted to explode when the mass of the white dwarf nears theChandrasekhar mass 4 - 1.4 solar masses. Here we show that the highredshift supernova SNLS-03D3bb has an exceptionallymore » high luminosity andlow kinetic energy that both imply a super-Chandrasekhar mass progenitor.Super-Chandrasekhar mass SNeIa shouldpreferentially occur in a youngstellar population, so this may provide an explanation for the observedtrend that overluminous SNe Ia only occur in young environments5;6. Sincethis supernova does not obey the relations that allow them to becalibrated as standard candles, and since no counterparts have been foundat low redshift, future cosmology studies will have to considercontamination from such events.« less

Constructing a cosmological model-independent Hubble diagram of type Ia supernovae with cosmic chronometers

NASA Astrophysics Data System (ADS)

Li, Zhengxiang; Gonzalez, J. E.; Yu, Hongwei; Zhu, Zong-Hong; Alcaniz, J. S.

2016-02-01

We apply two methods, i.e., the Gaussian processes and the nonparametric smoothing procedure, to reconstruct the Hubble parameter H (z ) as a function of redshift from 15 measurements of the expansion rate obtained from age estimates of passively evolving galaxies. These reconstructions enable us to derive the luminosity distance to a certain redshift z , calibrate the light-curve fitting parameters accounting for the (unknown) intrinsic magnitude of type Ia supernova (SNe Ia), and construct cosmological model-independent Hubble diagrams of SNe Ia. In order to test the compatibility between the reconstructed functions of H (z ), we perform a statistical analysis considering the latest SNe Ia sample, the so-called joint light-curve compilation. We find that, for the Gaussian processes, the reconstructed functions of Hubble parameter versus redshift, and thus the following analysis on SNe Ia calibrations and cosmological implications, are sensitive to prior mean functions. However, for the nonparametric smoothing method, the reconstructed functions are not dependent on initial guess models, and consistently require high values of H0, which are in excellent agreement with recent measurements of this quantity from Cepheids and other local distance indicators.

Using PS1 and Type Ia Supernovae To Make Most Precise Measurement of Dark Energy To Date

NASA Astrophysics Data System (ADS)

Scolnic, Daniel; Pan-STARRS

2018-01-01

I will review recent results that present optical light curves, redshifts, and classifications for 361 spectroscopically confirmed Type Ia supernovae (SNeIa) discovered by the Pan-STARRS1 (PS1) Medium Deep Survey. I will go over improvements to the PS1 SN photometry, astrometry and calibration that reduce the systematic uncertainties in the PS1 SN Ia distances. We combined distances of PS1 SNe with distance estimates of SNIa from SDSS, SNLS, various low-z and HST samples to form the largest combined sample of SN Ia consisting of a total of ~1050 SN Ia ranging from 0.01 < z < 2.3, which we call the ‘Pantheon Sample’. Photometric calibration uncertainties have long dominated the systematic error budget of every major analysis of cosmological parameters with SNIa. Using the PS1 relative calibration, we have reduced these calibration systematics to the point where they are similar in magnitude to the other major sources of known systematic uncertainties: the nature of the intrinsic scatter of SNIa and modeling of selection effects. I will present measurements of dark energy which are now the most precise measurements of dark energy to date.

Type-Ia Supernova Rates to Redshift 2.4 from Clash: The Cluster Lensing and Supernova Survey with Hubble

NASA Technical Reports Server (NTRS)

Graur, O.; Rodney, S. A.; Maoz, D.; Riess, A. G.; Jha, S. W.; Postman, M.; Dahlen, T.; Holoien, T. W.-S.; McCully, C.; Patel, B.;

Type-Ia supernova rates to redshift 2.4 from clash: The cluster lensing and supernova survey with Hubble

DOE Office of Scientific and Technical Information (OSTI.GOV)

Graur, O.; Rodney, S. A.; Riess, A. G.

2014-03-01

We present the supernova (SN) sample and Type-Ia SN (SN Ia) rates from the Cluster Lensing And Supernova survey with Hubble (CLASH). Using the Advanced Camera for Surveys and the Wide Field Camera 3 on the Hubble Space Telescope (HST), we have imaged 25 galaxy-cluster fields and parallel fields of non-cluster galaxies. We report a sample of 27 SNe discovered in the parallel fields. Of these SNe, ∼13 are classified as SN Ia candidates, including four SN Ia candidates at redshifts z > 1.2. We measure volumetric SN Ia rates to redshift 1.8 and add the first upper limit onmore » the SN Ia rate in the range 1.8 < z < 2.4. The results are consistent with the rates measured by the HST/GOODS and Subaru Deep Field SN surveys. We model these results together with previous measurements at z < 1 from the literature. The best-fitting SN Ia delay-time distribution (DTD; the distribution of times that elapse between a short burst of star formation and subsequent SN Ia explosions) is a power law with an index of −1.00{sub −0.06(0.10)}{sup +0.06(0.09)} (statistical){sub −0.08}{sup +0.12} (systematic), where the statistical uncertainty is a result of the 68% and 95% (in parentheses) statistical uncertainties reported for the various SN Ia rates (from this work and from the literature), and the systematic uncertainty reflects the range of possible cosmic star-formation histories. We also test DTD models produced by an assortment of published binary population synthesis (BPS) simulations. The shapes of all BPS double-degenerate DTDs are consistent with the volumetric SN Ia measurements, when the DTD models are scaled up by factors of 3-9. In contrast, all BPS single-degenerate DTDs are ruled out by the measurements at >99% significance level.« less

Selective suppression of the slow-inactivating potassium currents by nootropics in molluscan neurons.

PubMed

Bukanova, Julia V; Solntseva, Elena I; Skrebitsky, Vladimir G

2002-09-01

The role of the voltage-gated K+ channels in the effect of some nootropics was investigated. Earlier, the multiple effect of high concentrations of two nootropics, piracetam and its peptide analogue GVS-111 [Seredenin et al. (1995), US Patent No. 5,439,930], on Ca2+ and K+ currents of molluscan neurons was shown [Solntseva et al. (1997), General Pharmacology 29, 85-89]. In the present work, we describe the selective effect of low concentrations of these nootropics as well as vinpocetine on certain types of K+ current. The experiments were performed on isolated neurons of the land snail Helix pomatia using a two-microelectrode voltage-clamp method. The inward voltage-gated Ca2+ current (ICa) and three subtypes of the outward voltage-gated K+ current were recorded: Ca2+-dependent K+ current (IK(Ca)), delayed rectifying current (IKD), and fast-inactivating K+ current (IA). It has been found that I Ca was not changed in the presence of 30 microM vinpocetine, 100 microM piracetam or 10 nM GVS-111, while slow-inactivating, TEA-sensitive IK(Ca) and IKD were inhibited (IK(Ca) more strongly than IKD). In contrast, the fast-inactivating, 4-AP-sensitive K+ current (IA) was not diminished by low concentrations of piracetam and GVS-111, while vinpocetine even augmented it. A possible role of slow-inactivating subtypes of the K+ channels in the development of different forms of dementia is discussed.

Decreased voltage-gated potassium currents in rat dorsal root ganglion neurons after chronic constriction injury.

PubMed

Xiao, Yun; Wu, Yang; Zhao, Bo; Xia, Zhongyuan

2016-01-20

Voltage-gated potassium channels (KV) regulate pain transmission by controlling neuronal excitability. Changes in KV expression patterns may thus contribute toward hyperalgesia following nerve injury. The aim of this study was to characterize KV current density in dorsal root ganglion (DRG) neurons following chronic constriction injury (CCI) of the right sciatic nerve, a robust model of post-traumatic neuropathic pain. The study examined changes in small-diameter potassium ion currents (<30 µm) in neurons in the L4-L6 DRG following CCI by whole-cell patch-clamping and the association with post-CCI mechanical and thermal nociceptive thresholds. Compared with the control group, 7 days after CCI, the mechanical force and temperature required to elicit ipsilateral foot withdrawal decreased significantly, indicating tactile allodynia and thermal hyperalgesia. Post-CCI neurons had a significantly lower rheobase current and depolarized resting membrane potential than controls, suggesting KV current downregulation. Some ipsilateral DRG neurons also had spontaneous action potentials and repetitive firing. There was a 55% reduction in the total KV current density caused by a 55% decrease in the sustained delayed rectifier potassium ion current (IK) density and a 17% decrease in the transient A-type potassium ion current (IA) density. These results indicated that changes in DRG neuron IK and IA current density and concomitant afferent hyperexcitability may contribute toward neuropathic pain following injury. The rat CCI model may prove valuable for examining pathogenic mechanisms and potential therapies, such as KV channel modulators.

Supernova Cosmology Project

Science.gov Websites

Space Telescope Cluster Supernova Survey: II. The Type Ia Supernova Rate in High-Redshift Galaxy /abs/0809.1648 Constraining Dust and Color Variations of High-z SNe Using NICMOS on the Hubble Space /0804.4142 A New Determination of the High-Redshift Type Ia Supernova Rates with the Hubble Space Telescope

Radiation Transport in Type IA Supernovae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eastman, R

1999-11-16

It has been said more than once that the critical link between explosion models and observations is the ability to accurately simulate cooling and radiation transport in the expanding ejecta of Type Ia supernovae. It is perhaps frustrating to some of the theorists who study explosion mechanisms, and to some of the observers too, that more definitive conclusions have not been reached about the agreement, or lack thereof, between various Type Ia supernova models and the data. Although claims of superlative accuracy in transport simulations are sometimes made, I will argue here that there are outstanding issues of critical importancemore » and in need of addressing before radiation transport calculations are accurate enough to discriminate between subtly different explosion models.« less

Current management of symptomatic intracranial stenosis.

PubMed

Taylor, Robert A; Weigele, John B; Kasner, Scott E

2011-08-01

Intracranial arterial stenosis (IAS) is the cause of about 10% of all ischemic strokes in the United States, but may account for about 40% of strokes in some populations. After a stroke or transient ischemic attack due to IAS, patients face a 12% annual risk of recurrent stroke on medical therapy, with most strokes occurring in the first year. Warfarin is no better than aspirin in preventing recurrent strokes but poses a higher risk of serious bleeding and death. Groups with the highest risk of recurrent stroke are those with high-grade (≥ 70%) stenosis, those with recent symptom onset, those with symptoms precipitated by hemodynamic maneuvers, and women. Endovascular treatment of IAS is a rapidly evolving therapeutic option. Antiplatelet agents are currently recommended as the primary treatment for symptomatic IAS, with endovascular therapy reserved for appropriate high-risk cases refractory to medical therapy.

SPIRAL INSTABILITY CAN DRIVE THERMONUCLEAR EXPLOSIONS IN BINARY WHITE DWARF MERGERS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kashyap, Rahul; Fisher, Robert; García-Berro, Enrique

2015-02-10

Thermonuclear, or Type Ia supernovae (SNe Ia), originate from the explosion of carbon–oxygen white dwarfs, and serve as standardizable cosmological candles. However, despite their importance, the nature of the progenitor systems that give rise to SNe Ia has not been hitherto elucidated. Observational evidence favors the double-degenerate channel in which merging white dwarf binaries lead to SNe Ia. Furthermore, significant discrepancies exist between observations and theory, and to date, there has been no self-consistent merger model that yields a SNe Ia. Here we show that a spiral mode instability in the accretion disk formed during a binary white dwarf mergermore » leads to a detonation on a dynamical timescale. This mechanism sheds light on how white dwarf mergers may frequently yield SNe Ia.« less

Pancreatic islet amyloidosis, β-cell apoptosis, and α-cell proliferation are determinants of islet remodeling in type-2 diabetic baboons

PubMed Central

Guardado-Mendoza, Rodolfo; Davalli, Alberto M.; Chavez, Alberto O.; Hubbard, Gene B.; Dick, Edward J.; Majluf-Cruz, Abraham; Tene-Perez, Carlos E.; Goldschmidt, Lukasz; Hart, John; Perego, Carla; Comuzzie, Anthony G.; Tejero, Maria Elizabeth; Finzi, Giovanna; Placidi, Claudia; La Rosa, Stefano; Capella, Carlo; Halff, Glenn; Gastaldelli, Amalia; DeFronzo, Ralph A.; Folli, Franco

2009-01-01

β-Cell dysfunction is an important factor in the development of hyperglycemia of type-2 diabetes mellitus, and pancreatic islet amyloidosis (IA) has been postulated to be one of the main contributors to impaired insulin secretion. The aim of this study was to evaluate the correlation of IA with metabolic parameters and its effect on islets of Langerhans remodeling and relative endocrine-cell volume in baboons. We sequenced the amylin peptide, determined the fibrillogenic propensities, and evaluated pancreatic histology, clinical and biochemical characteristics, and endocrine cell proliferation and apoptosis in 150 baboons with different metabolic status. Amylin sequence in the baboon was 92% similar to humans and showed superimposable fibrillogenic propensities. IA severity correlated with fasting plasma glucose (FPG) (r = 0.662, P < 0.001) and HbA1c (r = 0.726, P < 0.001), as well as with free fatty acid, glucagon values, decreased homeostasis model assessment (HOMA) insulin resistance, and HOMA-B. IA severity was associated with a decreased relative β-cell volume, and increased relative α-cell volume and hyperglucagonemia. These results strongly support the concept that IA and β-cell apoptosis in concert with α-cell proliferation and hypertrophy are key determinants of islets of Langerhans “dysfunctional remodeling” and hyperglycemia in the baboon, a nonhuman primate model of type-2 diabetes mellitus. The most important determinants of IA were age and FPG (R2 = 0.519, P < 0.0001), and different FPG levels were sensitive and specific to predict IA severity. Finally, a predictive model for islet amyloid severity was generated with age and FPG as required variables. PMID:19666551

LKB1 promotes cell survival by modulating TIF-IA-mediated pre-ribosomal RNA synthesis under uridine downregulated conditions

PubMed Central

Liu, Xiuju; Huang, Henry; Wilkinson, Scott C.; Zhong, Diansheng; Khuri, Fadlo R.; Fu, Haian; Marcus, Adam; He, Yulong; Zhou, Wei

2016-01-01

We analyzed the mechanism underlying 5-aminoimidazole-4-carboxamide riboside (AICAR) mediated apoptosis in LKB1-null non-small cell lung cancer (NSCLC) cells. Metabolic profile analysis revealed depletion of the intracellular pyrimidine pool after AICAR treatment, but uridine was the only nucleotide precursor capable of rescuing this apoptosis, suggesting the involvement of RNA metabolism. Because half of RNA transcription in cancer is for pre-ribosomal RNA (rRNA) synthesis, which is suppressed by over 90% after AICAR treatment, we evaluated the role of TIF-IA-mediated rRNA synthesis. While the depletion of TIF-IA by RNAi alone promoted apoptosis in LKB1-null cells, the overexpression of a wild-type or a S636A TIF-IA mutant, but not a S636D mutant, attenuated AICAR-induced apoptosis. In LKB1-null H157 cells, pre-rRNA synthesis was not suppressed by AICAR when wild-type LKB1 was present, and cellular fractionation analysis indicated that TIF-IA quickly accumulated in the nucleus in the presence of a wild-type LKB1 but not a kinase-dead mutant. Furthermore, ectopic expression of LKB1 was capable of attenuating AICAR-induced death in AMPK-null cells. Because LKB1 promotes cell survival by modulating TIF-IA-mediated pre-rRNA synthesis, this discovery suggested that targeted depletion of uridine related metabolites may be exploited in the clinic to eliminate LKB1-null cancer cells. PMID:26506235

LKB1 promotes cell survival by modulating TIF-IA-mediated pre-ribosomal RNA synthesis under uridine downregulated conditions.

PubMed

Liu, Fakeng; Jin, Rui; Liu, Xiuju; Huang, Henry; Wilkinson, Scott C; Zhong, Diansheng; Khuri, Fadlo R; Fu, Haian; Marcus, Adam; He, Yulong; Zhou, Wei

2016-01-19

We analyzed the mechanism underlying 5-aminoimidazole-4-carboxamide riboside (AICAR) mediated apoptosis in LKB1-null non-small cell lung cancer (NSCLC) cells. Metabolic profile analysis revealed depletion of the intracellular pyrimidine pool after AICAR treatment, but uridine was the only nucleotide precursor capable of rescuing this apoptosis, suggesting the involvement of RNA metabolism. Because half of RNA transcription in cancer is for pre-ribosomal RNA (rRNA) synthesis, which is suppressed by over 90% after AICAR treatment, we evaluated the role of TIF-IA-mediated rRNA synthesis. While the depletion of TIF-IA by RNAi alone promoted apoptosis in LKB1-null cells, the overexpression of a wild-type or a S636A TIF-IA mutant, but not a S636D mutant, attenuated AICAR-induced apoptosis. In LKB1-null H157 cells, pre-rRNA synthesis was not suppressed by AICAR when wild-type LKB1 was present, and cellular fractionation analysis indicated that TIF-IA quickly accumulated in the nucleus in the presence of a wild-type LKB1 but not a kinase-dead mutant. Furthermore, ectopic expression of LKB1 was capable of attenuating AICAR-induced death in AMPK-null cells. Because LKB1 promotes cell survival by modulating TIF-IA-mediated pre-rRNA synthesis, this discovery suggested that targeted depletion of uridine related metabolites may be exploited in the clinic to eliminate LKB1-null cancer cells.

Delayed detonation models for normal and subluminous type Ia sueprnovae: Absolute brightness, light curves, and molecule formation

NASA Technical Reports Server (NTRS)

Hoflich, P.; Khokhlov, A. M.; Wheeler, J. C.

1995-01-01

We compute optical and infrared light curves of the pulsating class of delayed detonation models for Type Ia supernovae (SN Ia's) using an elaborate treatment of the Local Thermodynamic Equilbrium (LTE) radiation transport, equation of state and ionization balance, expansion opacity including the cooling by CO, Co(+), and SiO, and a Monte Carlo gamma-ray deposition scheme. The models have an amount of Ni-56 in the range from approximately or equal to 0.1 solar mass up to 0.7 solar mass depending on the density at which the transition from a deflagration to a detonation occurs. Models with a large nickel production give light curves comparable to those of typical Type Ia supernovae. Subluminous supernovae can be explained by models with a low nickel production. Multiband light curves are presented in comparison with the normally bright event SN 1992bc and the subluminous events Sn 1991bg and SN 1992bo to establish the principle that the delayed detonation paradigm in Chandrasekhar mass models may give a common explosion mechanism accounting for both normal and subluminous SN Ia's. Secondary IR-maxima are formed in the models of normal SN Ia's as a photospheric effect if the photospheric radius continues to increase well after maximum light. Secondary maxima appear later and stronger in models with moderate expansion velocities and with radioactive material closer to the surface. Model light curves for subluminous SN Ia's tend to show only one 'late' IR-maximum. In some delayed detonation models shell-like envelopes form, which consist of unburned carbon and oxygen. The formation of molecules in these envelopes is addressed. If the model retains a C/O-envelope and is subluminous, strong vibration bands of CO may appear, typically several weeks past maximum light. CO should be very weak or absent in normal Sn Ia's.

The Hubble Space Telescope Cluster Supernova Survey. II. The Type la Supernova rate in high-redshift galaxy clusters

DOE PAGES

Barbary, K.; Aldering, G.; Amanullah, R.; ...

2011-12-28

Here we report a measurement of the Type Ia supernova (SN Ia) rate in galaxy clusters at 0.9 < z < 1.46 from the Hubble Space Telescope Cluster Supernova Survey. This is the first cluster SN Ia rate measurement with detected z > 0.9 SNe. Finding 8 ± 1 cluster SNe Ia, we determine an SN Ia rate of 0.50 +0.23 -0.19 (stat) +0.10 -0.09 (sys) h 2 70 SNuB (SNuB ≡ 10 -12 SNe L -1 ⊙,B yr -1). In units of stellar mass, this translates to 0.36 + 0.16 -0.13 (stat) +0.07 -0.06 (sys) h 2 70 SNuMmore » (SNuM ≡ 10 -12 SNe M –1 ⊙ yr –1). This represents a factor of ≈ 5 ± 2 increase over measurements of the cluster rate at z < 0.2. We parameterize the late-time SN Ia delay time distribution (DTD) with a power law: Ψ(t)∝t s . Under the approximation of a single-burst cluster formation redshift of zf = 3, our rate measurement in combination with lower-redshift cluster SN Ia rates constrains s = –1.41 +0.47 –0.40, consistent with measurements of the DTD in the field. This measurement is generally consistent with expectations for the "double degenerate" scenario and inconsistent with some models for the "single degenerate" scenario predicting a steeper DTD at large delay times. We check for environmental dependence and the influence of younger stellar populations by calculating the rate specifically in cluster red-sequence galaxies and in morphologically early-type galaxies, finding results similar to the full cluster rate. Finally, the upper limit of one hostless cluster SN Ia detected in the survey implies that the fraction of stars in the intra-cluster medium is less than 0.47 (95% confidence), consistent with measurements at lower redshifts.« less

A Significantly off-center 56Ni Distribution for the Low-Luminosity Type Ia Supernova SN 2016brx from the 100IAS survey

NASA Astrophysics Data System (ADS)

Dong, Subo; Katz, Boaz; Kollmeier, Juna A.; Kushnir, Doron; Elias-Rosa, N.; Bose, Subhash; Morrell, Nidia; Prieto, J. L.; Chen, Ping; Kochanek, C. S.; Brandt, G. M.; Holoien, T. W.-S.; Gal-Yam, Avishay; Morales-Garoffolo, Antonia; Parker, Stuart; Phillips, M. M.; Piro, Anthony L.; Shappee, B. J.; Simon, Joshua D.; Stanek, K. Z.

2018-06-01

We present nebular-phase spectra of the Type Ia supernova (SN Ia) 2016brx, a member of the 1991bg-like subclass that lies at the faint end of the SN Ia luminosity function. Nebular spectra are available for only three other 1991bg-like SNe, and their Co line centers are all within ≲ 500 km/s of each other. In contrast, the nebular Co line center of SN 2016brx is blue-shifted by >1500 km/s compared to them and by ≈1200 km/s compared to the rest frame. This is a significant shift relative to the narrow nebular line velocity dispersion of ≲ 2000 km/s of these SNe. The large range of nebular line shifts implies that the 56Ni in the ejecta of SN 1991bg-like events is off-center by ˜1000 km/s rather than universally centrally confined as previously suggested. With the addition of SN 2016brx, the Co nebular line shapes of 1991bg-like objects appear to connect with the brighter SNe Ia that show double-peaked profiles, hinting at a continuous distribution of line profiles among SNe Ia. One class of models to produce both off-center and bi-modal 56Ni distributions is collisions of white dwarfs with unequal and equal masses.

Swift UVOT Grism Observations of Nearby Type Ia Supernovae - I. Observations and Data Reduction

NASA Astrophysics Data System (ADS)

Pan, Y.-C.; Foley, R. J.; Filippenko, A. V.; Kuin, N. P. M.

2018-05-01

Ultraviolet (UV) observations of Type Ia supernovae (SNe Ia) are useful tools for understanding progenitor systems and explosion physics. In particular, UV spectra of SNe Ia, which probe the outermost layers, are strongly affected by the progenitor metallicity. In this work, we present 120 Neil Gehrels Swift Observatory UV spectra of 39 nearby SNe Ia. This sample is the largest UV (λ < 2900 Å) spectroscopic sample of SNe Ia to date, doubling the number of UV spectra and tripling the number of SNe with UV spectra. The sample spans nearly the full range of SN Ia light-curve shapes (Δm15(B) ≈ 0.6-1.8 mag). The fast turnaround of Swift allows us to obtain UV spectra at very early times, with 13 out of 39 SNe having their first spectra observed ≳ 1 week before peak brightness and the earliest epoch being 16.5 days before peak brightness. The slitless design of the Swift UV grism complicates the data reduction, which requires separating SN light from underlying host-galaxy light and occasional overlapping stellar light. We present a new data-reduction procedure to mitigate these issues, producing spectra that are significantly improved over those of standard methods. For a subset of the spectra we have nearly simultaneous Hubble Space Telescope UV spectra; the Swift spectra are consistent with these comparison data.

Supernovae in the Subaru Deep Field: the rate and delay-time distribution of Type Ia supernovae out to redshift 2

NASA Astrophysics Data System (ADS)

Graur, O.; Poznanski, D.; Maoz, D.; Yasuda, N.; Totani, T.; Fukugita, M.; Filippenko, A. V.; Foley, R. J.; Silverman, J. M.; Gal-Yam, A.; Horesh, A.; Jannuzi, B. T.

2011-10-01

The Type Ia supernova (SN Ia) rate, when compared to the cosmic star formation history (SFH), can be used to derive the delay-time distribution (DTD; the hypothetical SN Ia rate versus time following a brief burst of star formation) of SNe Ia, which can distinguish among progenitor models. We present the results of a supernova (SN) survey in the Subaru Deep Field (SDF). Over a period of 3 years, we have observed the SDF on four independent epochs with Suprime-Cam on the Subaru 8.2-m telescope, with two nights of exposure per epoch, in the R, i'and z' bands. We have discovered 150 SNe out to redshift z≈ 2. Using 11 photometric bands from the observer-frame far-ultraviolet to the near-infrared, we derive photometric redshifts for the SN host galaxies (for 24 we also have spectroscopic redshifts). This information is combined with the SN photometry to determine the type and redshift distribution of the SN sample. Our final sample includes 28 SNe Ia in the range 1.0 < z < 1.5 and 10 in the range 1.5 < z < 2.0. As our survey is largely insensitive to core-collapse SNe (CC SNe) at z > 1, most of the events found in this range are likely SNe Ia. Our SN Ia rate measurements are consistent with those derived from the Hubble Space Telescope (HST) Great Observatories Origins Deep Survey (GOODS) sample, but the overall uncertainty of our 1.5 < z < 2.0 measurement is a factor of 2 smaller, of 35-50 per cent. Based on this sample, we find that the SN Ia rate evolution levels off at 1.0 < z < 2.0, but shows no sign of declining. Combining our SN Ia rate measurements and those from the literature, and comparing to a wide range of possible SFHs, the best-fitting DTD (with a reduced χ2= 0.7) is a power law of the form Ψ(t) ∝tβ, with index β=-1.1 ± 0.1 (statistical) ±0.17 (systematic). This result is consistent with other recent DTD measurements at various redshifts and environments, and is in agreement with a generic prediction of the double-degenerate progenitor scenario for SNe Ia. Most single-degenerate models predict different DTDs. By combining the contribution from CC SNe, based on the wide range of SFHs, with that from SNe Ia, calculated with the best-fitting DTD, we predict that the mean present-day cosmic iron abundance is in the range ZFe= (0.09-0.37) ZFe, ⊙. We further predict that the high-z SN searches now beginning with HST will discover 2-11 SNe Ia at z > 2.

30 CFR 57.22214 - Changes in ventilation (I-A, II-A, III, and V-A mines).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Changes in ventilation (I-A, II-A, III, and V-A mines). 57.22214 Section 57.22214 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... ventilation (I-A, II-A, III, and V-A mines). (a) Changes in ventilation which affect the main air current or...

30 CFR 57.22214 - Changes in ventilation (I-A, II-A, III, and V-A mines).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Changes in ventilation (I-A, II-A, III, and V-A mines). 57.22214 Section 57.22214 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... ventilation (I-A, II-A, III, and V-A mines). (a) Changes in ventilation which affect the main air current or...

Measuring the Growth Rate of Structure with Type IA Supernovae from LSST

NASA Astrophysics Data System (ADS)

Howlett, Cullan; Robotham, Aaron S. G.; Lagos, Claudia D. P.; Kim, Alex G.

2017-10-01

We investigate the peculiar motions of galaxies up to z = 0.5 using Type Ia supernovae (SNe Ia) from the Large Synoptic Survey Telescope (LSST) and predict the subsequent constraints on the growth rate of structure. We consider two cases. Our first is based on measurements of the volumetric SNe Ia rate and assumes we can obtain spectroscopic redshifts and light curves for varying fractions of objects that are detected pre-peak luminosity by LSST (some of which may be obtained by LSST itself, and others that would require additional follow-up observations). We find that these measurements could produce growth rate constraints at z< 0.5 that significantly outperform those found using Redshift Space Distortions (RSD) with DESI or 4MOST, even though there are ˜ 4× fewer objects. For our second case, we use semi-analytic simulations and a prescription for the SNe Ia rate as a function of stellar mass and star-formation rate to predict the number of LSST SNe IA whose host redshifts may already have been obtained with the Taipan+WALLABY surveys or with a future multi-object spectroscopic survey. We find ˜18,000 and ˜160,000 SNe Ia with host redshifts for these cases, respectively. While this is only a fraction of the total LSST-detected SNe Ia, they could be used to significantly augment and improve the growth rate constraints compared to only RSD. Ultimately, we find that combining LSST SNe Ia with large numbers of galaxy redshifts will provide the most powerful probe of large-scale gravity in the z< 0.5 regime over the coming decades.

Immunosuppressive Agents for the Treatment of Primary Sclerosing Cholangitis: A Systematic Review and Meta-Analysis.

PubMed

Peng, Xia; Luo, Xin; Hou, Jing-Ying; Wu, Shu-Yun; Li, Liang-Zong; Zheng, Ming-Hua; Wang, Ling-Yun

2017-01-01

Currently, there are no effective therapeutic agents for patients with primary sclerosing cholangitis (PSC). This study aimed to evaluate the safety and efficiency of immunosuppressive agents (IAs) for the treatment of PSC. The literatures were searched using the following keywords singly or in combination: PSC, treatments, IAs. The primary outcome was defined as the need for liver transplantation or mortality. Two hundred sixty six patients from 7 eligible studies were analyzed. IAs had no remarkable effects on the rate of mortality or liver transplantation (relative risk, RR 1.02, 95% CI 0.58-1.62, p = 0.92). Subgroup analyses showed no significant effect of IAs co-administration therapy (IAs co-administered with ursodeoxycholic acid, IA co-administered with IA; RR 1.41, 95% CI 0.40-4.95, p = 0.60). IAs caused adverse events (AEs) such as diarrhea, abdominal pain, and pruritus (RR 1.81, 95% CI 1.07-3.07, p = 0.03). IAs therapy did not significantly improve markers of liver function except for aspartate transaminase (weighted mean difference -9.76, 95% CI -12.92 to -6.6, p < 0.001). IAs administrated as either monotherapy or combination therapy do not reduce the risk of mortality or liver transplantation. IAs monotherapy is associated with AEs. © 2017 S. Karger AG, Basel.

A cosmology-independent calibration of type Ia supernovae data

NASA Astrophysics Data System (ADS)

Hauret, C.; Magain, P.; Biernaux, J.

2018-06-01

Recently, the common methodology used to transform type Ia supernovae (SNe Ia) into genuine standard candles has been suffering criticism. Indeed, it assumes a particular cosmological model (namely the flat ΛCDM) to calibrate the standardisation corrections parameters, i.e. the dependency of the supernova peak absolute magnitude on its colour, post-maximum decline rate and host galaxy mass. As a result, this assumption could make the data compliant to the assumed cosmology and thus nullify all works previously conducted on model comparison. In this work, we verify the viability of these hypotheses by developing a cosmology-independent approach to standardise SNe Ia data from the recent JLA compilation. Our resulting corrections turn out to be very close to the ΛCDM-based corrections. Therefore, even if a ΛCDM-based calibration is questionable from a theoretical point of view, the potential compliance of SNe Ia data does not happen in practice for the JLA compilation. Previous works of model comparison based on these data do not have to be called into question. However, as this cosmology-independent standardisation method has the same degree of complexity than the model-dependent one, it is worth using it in future works, especially if smaller samples are considered, such as the superluminous type Ic supernovae.

A Chandrasekhar mass progenitor for the Type Ia supernova remnant 3C 397 from the enhanced abundances of nickel and manganese

DOE PAGES

Yamaguchi, Hiroya; Badenes, Carles; Foster, Adam R.; ...

2015-03-12

Despite decades of intense efforts, many fundamental aspects of Type Ia supernovae (SNe Ia) remain elusive. One of the major open questions is whether the mass of an exploding white dwarf (WD) is close to the Chandrasekhar limit. Here, we report the detection of strong K-shell emission from stable Fe-peak elements in the Suzaku X-ray spectrum of the Type Ia supernova remnant (SNR) 3C 397. The high Ni/Fe and Mn/Fe mass ratios (0.11–0.24 and 0.018–0.033, respectively) in the hot plasma component that dominates the K-shell emission lines indicate a degree of neutronization in the supernova ejecta that can only bemore » achieved by electron capture in the dense cores of exploding WDs with a near-Chandrasekhar mass. This suggests a single-degenerate origin for 3C 397, since Chandrasekhar mass progenitors are expected naturally if the WD accretes mass slowly from a companion. Altogether with other results supporting the double-degenerate scenario, our work adds to the mounting evidence that both progenitor channels make a significant contribution to the SN Ia rate in star-forming galaxies.« less

Supernova rates from the Southern inTermediate Redshift ESO Supernova Search (STRESS)

NASA Astrophysics Data System (ADS)

Botticella, M. T.; Riello, M.; Cappellaro, E.; Benetti, S.; Altavilla, G.; Pastorello, A.; Turatto, M.; Greggio, L.; Patat, F.; Valenti, S.; Zampieri, L.; Harutyunyan, A.; Pignata, G.; Taubenberger, S.

2008-02-01

Aims:To measure the supernova (SN) rates at intermediate redshift we performed a search, the Southern inTermediate Redshift ESO Supernova Search (STRESS). Unlike most of the current high redshift SN searches, this survey was specifically designed to estimate the rate for both type Ia and core collapse (CC) SNe. Methods: We counted the SNe discovered in a selected galaxy sample measuring SN rate per unit blue band luminosity. Our analysis is based on a sample of 43 000 galaxies and on 25 spectroscopically confirmed SNe plus 64 selected SN candidates. Our approach is aimed at obtaining a direct comparison of the high redshift and local rates and at investigating the dependence of the rates on specific galaxy properties, most notably their colour. Results: The type Ia SN rate, at mean redshift z=0.3, is 0.22+0.10 +0.16-0.08 -0.14 h702 SNu, while the CC SN rate, at z=0.21, is 0.82+0.31 +0.30-0.24 -0.26 h702 SNu. The quoted errors are the statistical and systematic uncertainties. Conclusions: With respect to the local value, the CC SN rate at z=0.2 is higher by a factor of 2, whereas the type Ia SN rate remains almost constant. This implies that a significant fraction of SN Ia progenitors has a lifetime longer than 2{-}3 Gyr. We also measured the SN rates in the red and blue galaxies and found that the SN Ia rate seems to be constant in galaxies of different colour, whereas the CC SN rate seems to peak in blue galaxies, as in the local Universe. SN rates per unit volume were found to be consistent with other measurements showing a steeper evolution with redshift for CC SNe than SNe Ia. We have exploited the link between SFH and SN rates to predict the evolutionary behaviour of the SN rates and compare it with the path indicated by observations. We conclude that in order to constrain the mass range of CC SN progenitors and SN Ia progenitor models it is necessary to reduce the uncertainties in the cosmic SFH. In addition it is important to apply a consistent dust extinction correction both to SF and to CC SN rate and to measure the SN Ia rate in star forming and in passively evolving galaxies over a wide redshift range. Based on observations collected at the European Southern Observatory, using the 2.2 m MPG/ESO telescope on the La Silla (ESO Programmes 62.H-0833, 63.H-0322, 64.H-0390, 67.D-0422, 68.D-0273, 69.D-0453, 72.D-0670, 72.D-0745, 73.D-0670, 74.A-9008, 75.D-0662) and using Very Large Telescope on the Cerro Paranal (ESO Programme 74.D-0714). Table [see full textsee full textsee full text], Figs. [see full textsee full textsee full text]-[see full textsee full textsee full text] are only available in electronic form at http://www.aanda.org

Aortic Curvature Is a Predictor of Late Type Ia Endoleak and Migration After Endovascular Aneurysm Repair.

PubMed

Schuurmann, Richte C L; van Noort, Kim; Overeem, Simon P; Ouriel, Kenneth; Jordan, William D; Muhs, Bart E; 't Mannetje, Yannick; Reijnen, Michel; Fioole, Bram; Ünlü, Çağdaş; Brummel, Peter; de Vries, Jean-Paul P M

2017-06-01

To evaluate the association between aortic curvature and other preoperative anatomical characteristics and late (>1 year) type Ia endoleak and endograft migration in endovascular aneurysm repair (EVAR) patients. Eight high-volume EVAR centers contributed 116 EVAR patients (mean age 81±7 years; 103 men) to the study: 36 patients (mean age 82±7 years; 31 men) with endograft migration and/or type Ia endoleak diagnosed >1 year after the initial EVAR and 80 controls without early or late complications. Aortic curvature was calculated from the preoperative computed tomography scan as the maximum and average curvature over 5 predefined aortic segments: the entire infrarenal aortic neck, aneurysm sac, and the suprarenal, juxtarenal, and infrarenal aorta. Other morphological characteristics included neck length, neck diameter, mural neck calcification and thrombus, suprarenal and infrarenal angulation, and largest aneurysm sac diameter. Independent risk factors were identified using backward stepwise logistic regression. Relevant cutoff values for each of the variables in the final regression model were determined with the receiver operator characteristic curve. Logistic regression identified maximum curvature over the length of the aneurysm sac (>47 m -1 ; p=0.023), largest aneurysm sac diameter (>56 mm; p=0.028), and mural neck thrombus (>11° circumference; p<0.001) as independent predictors of late migration and type Ia endoleak. Aortic curvature is a predictor for late type Ia endoleak and endograft migration after EVAR. These findings suggest that aortic curvature is a better parameter than angulation to predict post-EVAR failure and should be included as a hostile neck parameter.

An absence of ex-companion stars in the type Ia supernova remnant SNR 0509-67.5.

PubMed

Schaefer, Bradley E; Pagnotta, Ashley

2012-01-11

A type Ia supernova is thought to begin with the explosion of a white dwarf star. The explosion could be triggered by the merger of two white dwarfs (a 'double-degenerate' origin), or by mass transfer from a companion star (the 'single-degenerate' path). The identity of the progenitor is still controversial; for example, a recent argument against the single-degenerate origin has been widely rejected. One way to distinguish between the double- and single-degenerate progenitors is to look at the centre of a known type Ia supernova remnant to see whether any former companion star is present. A likely ex-companion star for the progenitor of the supernova observed by Tycho Brahe has been identified, but that claim is still controversial. Here we report that the central region of the supernova remnant SNR 0509-67.5 (the site of a type Ia supernova 400 ± 50 years ago, based on its light echo) in the Large Magellanic Cloud contains no ex-companion star to a visual magnitude limit of 26.9 (an absolute magnitude of M(V) = +8.4) within a region of radius 1.43 arcseconds. (This corresponds to the 3σ maximum distance to which a companion could have been 'kicked' by the explosion.) This lack of any ex-companion star to deep limits rules out all published single-degenerate models for this supernova. The only remaining possibility is that the progenitor of this particular type Ia supernova was a double-degenerate system.

Multiple modes of a-type potassium current regulation.

PubMed

Cai, Shi-Qing; Li, Wenchao; Sesti, Federico

2007-01-01

Voltage-dependent potassium (K+) channels (Kv) regulate cell excitability by controlling the movement of K+ ions across the membrane in response to changes in the cell voltage. The Kv family, which includes A-type channels, constitute the largest group of K+ channel genes within the superfamily of Na+, Ca2+ and K+ voltage-gated channels. The name "A-type" stems from the typical profile of these currents that results form the opposing effects of fast activation and inactivation. In neuronal cells, A-type currents (I(A)), determine the interval between two consecutive action potentials during repetitive firing. In cardiac muscle, A-type currents (I(to)), control the initial repolarization of the myocardium. Structurally, A-type channels are tetramers of alpha-subunits each containing six putative transmembrane domains including a voltage-sensor. A-type channels can be modulated by means of protein-protein interactions with so-called beta-subunits that control inactivation voltage sensitivity and other properties, and by post-transcriptional modifications such as phosphorylation or oxidation. Recently a new mode of A-type regulation has been discovered in the form of a class of hybrid beta-subunits that posses their own enzymatic activity. Here, we review the biophysical and physiological properties of these multiple modes of A-type channel regulation.

Spectroscopic Classification of MASTER OT J110707.62-052244.0 as a Type Ia Supernova

NASA Astrophysics Data System (ADS)

Zheng, W.; Kim, M.; Shivvers, I.; Yuk, H.; Filippenko, A. V.

2015-11-01

We report that inspection of a CCD spectrum (range 350-1050 nm) of MASTER OT J110707.62-052244.0 (ATel #8236), obtained on Nov. 11.57 UT with the Shane 3-m reflector (+ Kast spectrograph) at Lick Observatory, shows that the object is a normal Type Ia supernova roughly 1 week past maximum brightness.

Spectroscopic Classification of PSN J07051005+2102327: a Type Ia Supernova

NASA Astrophysics Data System (ADS)

Shivvers, I.; Yuk, H.; Filippenko, A. V.; U, V.

2015-11-01

We report that inspection of a low signal-to-noise ratio CCD spectrum (range 350-1050 nm) of PSN J07051005+2102327 (CBAT TOCP), obtained on Nov. 17.46 UT with the Shane 3-m reflector (+ Kast spectrograph) at Lick Observatory, shows that the object is a normal Type Ia supernova within a few days of maximum brightness.

ASCA Observations of LMC SNRS

NASA Technical Reports Server (NTRS)

Hughes, John P.

1999-01-01

We present our first results from a study of the supernova remnants (SNRs) in the Large Magellanic Cloud (LMC) using data from ASCA. The three remnants we have analyzed to date, 0509-67.5, 0519-69.0, and N103B, are among the smallest, and presumably also the youngest, in the Cloud. The X-ray spectra of these SNRs show strong K(alpha) emission lines of silicon, sulfur, argon, and calcium with no evidence for corresponding lines of oxygen, neon, or magnesium. The dominant feature in the spectra is a broad blend of emission lines around 1 keV which we attribute to L-shell emission lines of iron. Model calculations (Nomoto, Thielemann, & Yokoi 1984) show that the major products of nucleosynthesis in Type Ia supernovae (SNs) are the elements from silicon to iron, as observed here. The calculated nucleosynthetic yields from Type Ib and II SNs are shown to be qualitatively inconsistent with the data. We conclude that the SNs which produced these remnants were of Type Ia. This finding also confirms earlier suggestions that the class of Balmer-dominated remnants arise from Type Ia SN explosions. Based an these early results from the LMC SNR sample, we find that roughly one-half of the SNRs produced in the LMC within the last approximately 1500 yr came from Type Ia SNs.

A common explosion mechanism for type Ia supernovae.

PubMed

Mazzali, Paolo A; Röpke, Friedrich K; Benetti, Stefano; Hillebrandt, Wolfgang

2007-02-09

Type Ia supernovae, the thermonuclear explosions of white dwarf stars composed of carbon and oxygen, were instrumental as distance indicators in establishing the acceleration of the universe's expansion. However, the physics of the explosion are debated. Here we report a systematic spectral analysis of a large sample of well-observed type Ia supernovae. Mapping the velocity distribution of the main products of nuclear burning, we constrain theoretical scenarios. We find that all supernovae have low-velocity cores of stable iron-group elements. Outside this core, nickel-56 dominates the supernova ejecta. The outer extent of the iron-group material depends on the amount of nickel-56 and coincides with the inner extent of silicon, the principal product of incomplete burning. The outer extent of the bulk of silicon is similar in all supernovae, having an expansion velocity of approximately 11,000 kilometers per second and corresponding to a mass of slightly over one solar mass. This indicates that all the supernovae considered here burned similar masses and suggests that their progenitors had the same mass. Synthetic light-curve parameters and three-dimensional explosion simulations support this interpretation. A single explosion scenario, possibly a delayed detonation, may thus explain most type Ia supernovae.

SNACC Extras

NASA Astrophysics Data System (ADS)

Huber, Mark; Scolnic, D.; Riess, A. G.; Tonry, J. L.; Rodney, S. A.; Rest, A.; Stubbs, C. W.

2010-01-01

The extensive application of the SuperNovAe Cross-Correlation (SNACC) filters developed by Scolnic et al. (2009) for follow-up identification and redshift of type Ia supernovae in current and upcoming supernovae surveys will itself produce a unique imaging survey. We will present a collection of simulated and actual sources from the initial observing run using the new 4-band SNACC filters with Suprime-Cam on the Subaru telescope to explore the extra potential of this unique data set.

Mass retention efficiencies of He accretion onto carbon-oxygen white dwarfs and type Ia supernovae

NASA Astrophysics Data System (ADS)

Wu, C.; Wang, B.; Liu, D.; Han, Z.

2017-07-01

Context. Type Ia supernovae (SNe Ia) play a crucial role in studying cosmology and galactic chemical evolution. They are thought to be thermonuclear explosions of carbon-oxygen white dwarfs (CO WDs) when their masses reach the Chandrasekar mass limit in binaries. Previous studies have suggested that He novae may be progenitor candidates of SNe Ia. However, the mass retention efficiencies during He nova outbursts are still uncertain. Aims: In this article, we aim to study the mass retention efficiencies of He nova outbursts and to investigate whether SNe Ia can be produced through He nova outbursts. Methods: Using the stellar evolution code Modules for Experiments in Stellar Astrophysics, we simulated a series of multicycle He-layer flashes, in which the initial WD masses range from 0.7 to 1.35 M⊙ with various accretion rates. Results: We obtained the mass retention efficiencies of He nova outbursts for various initial WD masses, which can be used in the binary population synthesis studies. In our simulations, He nova outbursts can increase the mass of the WD to the Chandrasekar mass limit and the explosive carbon burning can be triggered in the center of the WD; this suggests that He nova outbursts can produce SNe Ia. Meanwhile, the mass retention efficiencies in the present work are lower than those of previous studies, which leads to a lower birthrates of SNe Ia through the WD + He star channel. Furthermore, we obtained the elemental abundances distribution at the moment of explosive carbon burning, which can be used as the initial input parameters in studying explosion models of SNe Ia.

Evidence for a Sub-Chandrasekhar-mass Type Ia Supernova in the Ursa Minor Dwarf Galaxy

NASA Astrophysics Data System (ADS)

McWilliam, Andrew; Piro, Anthony L.; Badenes, Carles; Bravo, Eduardo

2018-04-01

A long-standing problem is identifying the elusive progenitors of Type Ia supernovae (SNe Ia), which can roughly be split into Chandraksekhar and sub-Chandrasekhar-mass events. An important difference between these two cases is the nucleosynthetic yield, which is altered by the increased neutron excess in Chandrasekhar progenitors due to their pre-explosion simmering and high central density. Based on these arguments, we show that the chemical composition of the most metal-rich star in the Ursa Minor dwarf galaxy, COS 171, is dominated by nucleosynthesis from a low-metallicity, low-mass, sub-Chandrasekhar-mass SN Ia. Key diagnostic abundance ratios include Mn/Fe and Ni/Fe, which could not have been produced by a Chandrasekhar-mass SN Ia. Large deficiencies of Ni/Fe, Cu/Fe and Zn/Fe also suggest the absence of alpha-rich freeze-out nucleosynthesis, favoring low-mass white dwarf progenitors of SNe Ia, near 0.95 M ⊙, from comparisons to numerical detonation models. We also compare Mn/Fe and Ni/Fe ratios to the recent yields predicted by Shen et al., finding consistent results. To explain the [Fe/H] at ‑1.35 dex for COS 171 would require dilution of the SN Ia ejecta with ∼104 M ⊙ of material, which is expected for an SN remnant expanding into a warm interstellar medium with n ∼ 1 cm‑3. In the future, finding more stars with the unique chemical signatures we highlight here will be important for constraining the rate and environments of sub-Chandrasekhar SNe Ia.

The Host Galaxies of Type Ia Supernovae Discovered by the Palomar Transient Factory

NASA Technical Reports Server (NTRS)

Pan, Y.-C.; Sullivan, M.; McGuire, K.; Hook, I. M.; Nugent, P. E.; Howell, D. A.; Arcavi, I.; Botyanszki, J.; Cenko, Stephen Bradley; DeRose, J.

2013-01-01

We present spectroscopic observations of the host galaxies of 82 low-redshift type Ia supernovae (SNe Ia) discovered by the Palomar Transient Factory (PTF). We determine star-formation rates, gas-phase stellar metallicities, and stellar masses and ages of these objects. As expected, strong correlations between the SN Ia light-curve width (stretch) and the host age mass metallicity are found: fainter, faster-declining events tend to be hosted by older massive metal-rich galaxies. There is some evidence that redder SNe Ia explode in higher metallicity galaxies, but we found no relation between the SN colour and host galaxy extinction based on the Balmer decrement, suggesting that the colour variation of these SNe does not primarily arise from this source. SNe Ia in higher-mass metallicity galaxies also appear brighter after stretch colour corrections than their counterparts in lower mass hosts, and the stronger correlation is with gas-phase metallicity suggesting this may be the more important variable. We also compared the host stellar mass distribution to that in galaxy targeted SN surveys and the high-redshift untargeted Supernova Legacy Survey (SNLS). SNLS has many more low mass galaxies, while the targeted searches have fewer. This can be explained by an evolution in the galaxy stellar mass function, coupled with a SN delay-time distribution proportional to t1. Finally, we found no significant difference in the mass--metallicity relation of our SN Ia hosts compared to field galaxies, suggesting any metallicity effect on the SN Ia rate is small.

ANO1 in intramuscular interstitial cells of Cajal plays a key role in the generation of slow waves and tone in the internal anal sphincter

PubMed Central

Hannah, E. E.; Zhu, M. H.; Lyle, H. E.; Rock, J. R.; Sanders, K. M.; Ward, S. M.; Keef, K. D.

2017-01-01

Key points The internal anal sphincter develops tone important for maintaining high anal pressure and continence. Controversy exists regarding the mechanisms underlying tone development.We examined the hypothesis that tone depends upon electrical slow waves (SWs) initiated in intramuscular interstitial cells of Cajal (ICC‐IM) by activation of Ca2+‐activated Cl− channels (ANO1, encoded by Ano1) and voltage‐dependent L‐type Ca2+ channels (CavL, encoded by Cacna1c).Measurement of membrane potential and contraction indicated that ANO1 and CavL have a central role in SW generation, phasic contractions and tone, independent of stretch.ANO1 expression was examined in wildtype and Ano1/+egfp mice with immunohistochemical techniques. Ano1 and Cacna1c expression levels were examined by quantitative PCR in fluorescence‐activated cell sorting.ICC‐IM were the predominant cell type expressing ANO1 and the most likely candidate for SW generation. SWs in ICC‐IM are proposed to conduct to smooth muscle where Ca2+ entry via CavL results in phasic activity that sums to produce tone. Abstract The mechanism underlying tone generation in the internal anal sphincter (IAS) is controversial. We examined the hypothesis that tone depends upon generation of electrical slow waves (SWs) initiated in intramuscular interstitial cells of Cajal (ICC‐IM) by activation of Ca2+‐activated Cl− channels (encoded by Ano1) and voltage‐dependent L‐type Ca2+ channels (encoded by Cacna1c). Phasic contractions and tone in the IAS were nearly abolished by ANO1 and CavL antagonists. ANO1 antagonists also abolished SWs as well as transient depolarizations that persisted after addition of CavL antagonists. Tone development in the IAS did not require stretch of muscles, and the sensitivity of contraction to ANO1 antagonists was the same in stretched versus un‐stretched muscles. ANO1 expression was examined in wildtype and Ano1/+egfp mice with immunohistochemical techniques. Dual labelling revealed that ANO1 expression could be resolved in ICC but not smooth muscle cells (SMCs) in the IAS and rectum. Ano1, Cacna1c and Kit gene expression were the same in extracts of IAS and rectum muscles. In IAS cells isolated with fluorescence‐activated cell sorting, Ano1 expression was 26.5‐fold greater in ICC than in SMCs while Cacna1c expression was only 2‐fold greater in SMCs than in ICC. These data support a central role for ANO1 and CavL in the generation of SWs and tone in the IAS. ICC‐IM are the probable cellular candidate for ANO1 currents and SW generation. We propose that ANO1 and CavL collaborate to generate SWs in ICC‐IM followed by conduction to adjacent SMCs where phasic calcium entry through CavL sums to produce tone. PMID:28054347

Supernovae In The Subaru Deep Field: The Rate And Delay-time Distribution Of Type Ia Supernovae Out To Redshift 2

NASA Astrophysics Data System (ADS)

Graur, Or; SDF SN Team

2012-01-01

The Type Ia supernova (SN Ia) rate, when compared to the cosmic star formation history (SFH), can be used to derive the delay-time distribution (DTD; the hypothetical SN Ia rate versus time following a brief burst of star formation) of SNe Ia, which can distinguish among progenitor models. We present the results of a supernova (SN) survey in the Subaru Deep Field (SDF). Over a period of 3 years, we have observed the SDF on four independent epochs with Suprime-Cam on the Subaru 8.2-m telescope, with two nights of exposure per epoch, in the R, i'and z‧ bands. We have discovered 150 SNe out to redshift z≈ 2. Our final sample includes 28 SNe Ia in the range 1.0 < z < 1.5 and 10 in the range 1.5 < z < 2.0. As our survey is largely insensitive to core-collapse SNe (CC SNe) at z > 1, most of the events found in this range are likely SNe Ia. Based on this sample, we find that the SN Ia rate evolution levels off at 1.0 < z < 2.0, but shows no sign of declining. Combining our SN Ia rate measurements and those from the literature, and comparing to a wide range of possible SFHs, the best-fitting DTD (with a reduced χ2= 0.7) is a power law of the form &Psi(t) ∝tβ, with index β=-1.1 ± 0.1 (statistical) ±0.17 (systematic). By combining the contribution from CC SNe, based on the wide range of SFHs, with that from SNe Ia, calculated with the best-fitting DTD, we predict that the mean present-day cosmic iron abundance is in the range ZFe= (0.09-0.37) ZFe, ⊙.

Merging of a CO WD and a He-rich WD to produce a type Ia supernovae

NASA Astrophysics Data System (ADS)

Liu, D.; Wang, B.; Wu, C.; Han, Z.

2017-10-01

Context. Although type Ia supernovae (SNe Ia) play a key role in astrophysics, the companions of the exploding carbon-oxygen white dwarfs (CO WDs) are still not completely identified. It has been suggested recently that a He-rich WD (a He WD or a hybrid HeCO WD) that merges with a CO WD may produce an SN Ia. This theory was based on the double-detonation model, in which the shock compression in the CO core caused by the surface explosion of the He-rich shell might lead to the explosion of the whole CO WD. However, so far, very few binary population synthesis (BPS) studies have been made on the merger scenario of a CO WD and a He-rich WD in the context of SNe Ia. Aims: We aim to systematically study the Galactic birthrates and delay-time distributions of SNe Ia based on the merger scenario of a CO WD and a He-rich WD. Methods: We performed a series of Monte Carlo BPS simulations to investigate the properties of SNe Ia from the merging of a CO WD and a He-rich WD based on the Hurley rapid binary evolution code. We also considered the influence of different metallicities on the final results. Results: From our simulations, we found that no more than 15% of all SNe Ia stem from the merger scenario of a CO WD and a He-rich WD, and their delay times range from 110 Myr to the Hubble time. This scenario mainly contributes to SN Ia explosions with intermediate and long delay times. The present work indicates that the merger scenario of a CO WD and a He-rich WD can roughly reproduce the birthrates of SN 1991bg-like events, and cover the range of their delay times. We also found that SN Ia birthrates from this scenario would be higher for the cases with low metallicities.

ASCA observations of the Large Magellanic Cloud supernova remnant sample: Typing supernovae from their remnants

NASA Technical Reports Server (NTRS)

Hughes, John P.; Hayashi, Ichizo; Helfand, David; Hwang, Una; Itoh, Masayuki; Kirshner, Robert; Koyama, Katsuji; Markert, Thomas; Tsunemi, Hiroshi; Woo, Jonathan

1995-01-01

We present our first results from a study of the supernova remnants (SNRs) in the Large Magellanic Cloud (LMC) using data from ASCA. The three remnants we have analyzed to date, 0509-67.5, 0519-69.0, and N103B, are among the smallest, and presumably also the youngest, in the Cloud. The X-ray spectra of these SNRs show strong K alpha emission lines of silicon, sulfur, argon, and calcium with no evidence for corresponding lines of oxygen, neon, or magnesium. The dominant feature in the spectra is a broad blend of emission lines around 1 keV which we attribute to L-shell emission lines of iron. Model calculations (Nomoto, Thielemann, & Yokoi 1984) show that the major products of nucleosynthesis in Type Ia supernovae (SNs) are the elements from silicon to iron, as observed here. The calculated nucleosynthetic yields from Type Ib and II SNs are shown to be qualitatively inconsistent with the data. We conclude that the SNs which produced these remnants were of Type Ia. This finding also confirms earlier suggestions that the class of Balmer-dominated remnants arise from Type Ia SN explosions. Based on these early results from the LMC SNR sample, we find that roughly one-half of the SNRs produced in the LMC within the last approximately 1500 yr came from Type Ia SNs.

Recent development and gene therapy for glycogen storage disease type Ia.

PubMed

Chou, Janice Y; Kim, Goo-Young; Cho, Jun-Ho

2017-09-01

Glycogen storage disease type Ia (GSD-Ia) is an autosomal recessive metabolic disorder caused by a deficiency in glucose-6-phosphatase-α (G6Pase-α or G6PC) that is expressed primarily in the liver, kidney, and intestine. G6Pase-α catalyzes the hydrolysis of glucose-6-phosphate (G6P) to glucose and phosphate in the terminal step of gluconeogenesis and glycogenolysis, and is a key enzyme for endogenous glucose production. The active site of G6Pase-α is inside the endoplasmic reticulum (ER) lumen. For catalysis, the substrate G6P must be translocated from the cytoplasm into the ER lumen by a G6P transporter (G6PT). The functional coupling of G6Pase-α and G6PT maintains interprandial glucose homeostasis. Dietary therapies for GSD-Ia are available, but cannot prevent the long-term complication of hepatocellular adenoma that may undergo malignant transformation to hepatocellular carcinoma. Animal models of GSD-Ia are now available and are being exploited to both delineate the disease more precisely and develop new treatment approaches, including gene therapy.

Modified Einstein's gravity as a possible missing link between sub- and super-Chandrasekhar type Ia supernovae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Das, Upasana; Mukhopadhyay, Banibrata, E-mail: upasana@physics.iisc.ernet.in, E-mail: bm@physics.iisc.ernet.in

2015-05-01

We explore the effect of modification to Einstein's gravity in white dwarfs for the first time in the literature, to the best of our knowledge. This leads to significantly sub- and super-Chandrasekhar limiting masses of white dwarfs, determined by a single model parameter. On the other hand, type Ia supernovae (SNeIa), a key to unravel the evolutionary history of the universe, are believed to be triggered in white dwarfs having mass close to the Chandrasekhar limit. However, observations of several peculiar, under- and over-luminous SNeIa argue for exploding masses widely different from this limit. We argue that explosions of themore » modified gravity induced sub- and super-Chandrasekhar limiting mass white dwarfs result in under- and over-luminous SNeIa respectively, thus unifying these two apparently disjoint sub-classes and, hence, serving as a missing link. Our discovery raises two fundamental questions. Is the Chandrasekhar limit unique? Is Einstein's gravity the ultimate theory for understanding astronomical phenomena? Both the answers appear to be no!.« less

Cell-autonomous excitation of midbrain dopamine neurons by endocannabinoid-dependent lipid signaling

PubMed Central

Gantz, Stephanie C.; Bean, Bruce P.

2017-01-01

SUMMARY The major endocannabinoid in the mammalian brain is the bioactive lipid 2-arachidonoylglycerol (2-AG). The best-known effects of 2-AG are mediated by G protein-coupled cannabinoid receptors. In principle, 2-AG could modify neuronal excitability by acting directly on ion channels, but such mechanisms are poorly understood. Using a preparation of dissociated mouse midbrain dopamine neurons to isolate effects on intrinsic excitability, we found that 100 nM 2-AG accelerated pacemaking and steepened the frequency-current relationship for burst-like firing. In voltage-clamp experiments, 2-AG reduced A-type potassium current (IA) through a cannabinoid receptor-independent mechanism mimicked by arachidonic acid, which has no activity on cannabinoid receptors. Activation of orexin, neurotensin, and metabotropic glutamate Gq/11-linked receptors mimicked the effects of exogenous 2-AG and their actions were prevented by inhibiting the 2-AG-synthesizing enzyme diacylglycerol lipase α. The results show that 2-AG and related lipid signaling molecules can directly tune neuronal excitability in a cell-autonomous manner by modulating IA. PMID:28262417

Nearby Supernova Factory Observations of SN 2006D: On SporadicCarbon Signatures in Early Type Ia Supernova Spectra

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas, R.C.; Aldering, G.; Antilogus, P.

2006-10-12

We present four spectra of the Type Ia supernova SN Ia 2006Dextending from -7 to +13 days with respect to B-band maximum. The spectrainclude the strongest signature of unburned material at photosphericvelocities observed in a SN Ia to date. The earliest spectrum exhibits CII absorption features below 14,000 km/s, including a distinctive C IIlambda 6580 absorption feature. The carbon signatures dissipate as the SNapproaches peak brightness. In addition to discussing implications ofphotospheric-velocity carbon for white dwarf explosion models, we outlinesome factors that may influence the frequency of its detection before andaround peak brightness. Two effects are explored in this regard,includingmore » depopulation of the C II optical levels by non-LTE effects, andline-of-sight effects resulting from a clumpy distribution of unburnedmaterial with low volume-filling factor.« less

Ultraviolet Spectroscopy of Supernovae: The First Two Years of Swift Observations

NASA Technical Reports Server (NTRS)

Immler, Stefan

2008-01-01

We present the entire sample of ultraviolet (1JV) spectra of supernovae (SNe) obtained with the Ultraviolet/Optical Telescope (UVOT) on board the Swift satellite during the first 2 years of observations (2005/2006). A total of 31 UV-grism and 22 V-grism spectra of 9 supernovae (SNe) have been collected. of which 6 are thermonuclear (type Ia) and 3 core collapse (type Ibc/II) SNe. All the spectra have been obtained during the photospheric phase. After a comparison of the spectra of our sample with those in the literature (SNe 1992A. 1990N and 1999em). we confirm some degree of diversity in the UV emission of Type Ia SNe and a greater homogeneity in the Type I1 Plateau SN sample. Signatures of interaction between the ejecta and the circumstellar environment have been found in the UV spectrum of SN 2006jc, the only SN Type Ib/c for which UVOT grism data are available. Currently, Swift LJVOT is the best suited instrument for early SN studies in the UV due to its fast response and flexible scheduling capabilities. However. in order to increase the quality of the data and significantly improve our understanding of the lJV properties of SNe and to fully maximize the scientific potential of UVOT grism observations. a larger investment in obsening time and longer exposures are needed.

Cosmic transparency and acceleration

NASA Astrophysics Data System (ADS)

Holanda, R. F. L.; Pereira, S. H.; Jain, Deepak

2018-01-01

In this paper, by considering an absorption probability independent of photon wavelength, we show that current type Ia supernovae (SNe Ia) and gamma-ray burst (GRB) observations plus high-redshift measurements of the cosmic microwave background (CMB) radiation temperature support cosmic acceleration regardless of the transparent-universe assumption. Two flat scenarios are considered in our analyses: the Λ CDM model and a kinematic model. We consider τ (z )=2 ln (1 +z )ɛ, where τ (z ) denotes the opacity between an observer at z =0 and a source at z . This choice is equivalent to deforming the cosmic distance duality relation as DLDA-1=(1 +z )2+ɛ and, if the absorption probability is independent of photon wavelength, the CMB temperature evolution law is TCMB(z )=T0(1 +z )1+2 ɛ /3. By marginalizing on the ɛ parameter, our analyses rule out a decelerating universe at 99.99% C.L. for all scenarios considered. Interestingly, by considering only SNe Ia and GRBs observations, we obtain that a decelerated universe—indicated by ΩΛ≤0.33 and q0>0 —is ruled out around 1.5 σ C.L. and 2 σ C.L., respectively, regardless of the transparent-universe assumption.

Deficiency in the nuclear factor E2-related factor 2 renders pancreatic β-cells vulnerable to arsenic-induced cell damage

PubMed Central

Yang, Bei; Fu, Jingqi; Zheng, Hongzhi; Xue, Peng; Yarborough, Kathy; Woods, Courtney G; Hou, Yongyong; Zhang, Qiang; Andersen, Melvin E.; Pi, Jingbo

2012-01-01

Chronic human exposure to inorganic arsenic (iAs), a potent environmental oxidative stressor, is associated with increased prevalence of Type 2 diabetes, where impairment of pancreatic β-cell function is a key pathogenic factor. Nuclear factor E2-related factor 2 (Nrf2) is a central transcription factor regulating cellular adaptive response to oxidative stress. However, persistent activation of Nrf2 in response to chronic oxidative stress, including inorganic arsenite (iAs3+) exposure, blunts glucose-triggered reactive oxygen species (ROS) signaling and impairs glucose-stimulated insulin secretion (GSIS). In the current study, we found that MIN6 pancreatic β-cells with stable knockdown of Nrf2 (Nrf2-KD) by lentiviral shRNA and pancreatic islets isolated from Nrf2-knockout (Nrf2−/−) mice exhibited reduced expression of several antioxidant and detoxification enzymes in response to acute iAs3+ exposure. As a result, Nrf2-KD MIN6 cells and Nrf2−/− islets were more susceptible to iAs3+ and monomethylarsonous acid (MMA3+)-induced cell damage, as measured by decreased cell viability, augmented apoptosis and morphological change. Pretreatment of MIN6 cells with Nrf2 activator tert-butylhydroquinone protected the cells from iAs3+-induced cell damage in an Nrf2-dependent fashion. In contrast, antioxidant N-acetyl cysteine protected Nrf2-KD MIN6 cells against acute cytotoxicity of iAs3+. The present study demonstrates that Nrf2-mediated antioxidant response is critical in the pancreatic β-cell defense mechanism against acute cytotoxicity by arsenic. The findings here, combined with our previous results on the inhibitory effect of antioxidants on ROS signaling and GSIS, suggest that Nrf2 plays paradoxical roles in pancreatic β-cell dysfunction induced by environmental arsenic exposure. PMID:23000044

Is there a concordance value for H0?

NASA Astrophysics Data System (ADS)

Luković, Vladimir V.; D'Agostino, Rocco; Vittorio, Nicola

2016-11-01

Context. We test the theoretical predictions of several cosmological models against different observables to compare the indirect estimates of the current expansion rate of the Universe determined from model fitting with the direct measurements based on Cepheids data published recently. Aims: We perform a statistical analysis of type Ia supernova (SN Ia), Hubble parameter, and baryon acoustic oscillation data. A joint analysis of these datasets allows us to better constrain cosmological parameters, but also to break the degeneracy that appears in the distance modulus definition between H0 and the absolute B-band magnitude of SN Ia, M0. Methods: From the theoretical side, we considered spatially flat and curvature-free ΛCDM, wCDM, and inhomogeneous Lemaître-Tolman-Bondi (LTB) models. To analyse SN Ia we took into account the distributions of SN Ia intrinsic parameters. Results: For the ΛCDM model we find that Ωm = 0.35 ± 0.02, H0 = (67.8 ± 1.0) km s-1 Mpc-1, while the corrected SN absolute magnitude has a normal distribution N(19.13,0.11). The wCDM model provides the same value for Ωm, while H0 = (66.5 ± 1.8) km s-1 Mpc-1 and w = -0.93 ± 0.07. When an inhomogeneous LTB model is considered, the combined fit provides H0 = (64.2 ± 1.9) km s-1 Mpc-1. Conclusions: Both the Akaike information criterion and the Bayes factor analysis cannot clearly distinguish between ΛCDM and wCDM cosmologies, while they clearly disfavour the LTB model. For the ΛCDM, our joint analysis of the SN Ia, the Hubble parameter, and the baryon acoustic oscillation datasets provides H0 values that are consistent with cosmic microwave background (CMB)-only Planck measurements, but they differ by 2.5σ from the value based on Cepheids data.

Selective blockade of a slowly inactivating potassium current in striatal neurons by (+/-) 6-chloro-APB hydrobromide (SKF82958).

PubMed

Nisenbaum, E S; Mermelstein, P G; Wilson, C J; Surmeier, D J

1998-07-01

The ion channels of rat striatal neurons are known to be modulated by stimulation of D1 dopamine receptors. The susceptibility of depolarization-activated K+ currents to be modulated by the D1 agonist, 6-chloro-7,8-dihydroxy-3-allyl-1-phenyl-2,3,4,5-tetra-hydro-1H-3-benzaze pine (APB) was investigated using whole-cell voltage-clamp recording techniques from acutely isolated neurons. APB (0.01-100 microM) produced a concentration-dependent reduction in the total K+ current. At intermediate concentrations (ca. 10 microM), APB selectively depressed the slowly inactivating A-current (I(As)). A similar effect was produced by application of the D1 agonist, 7,8-dihydroxy-1-phenyl-2,3,4,5-tetrahydro-1-H-2-benzazepine (SKF38393, 10 microM). APB reduced I(As) rapidly, having onset and recovery time constants of 1.2 sec and 1.6 sec, respectively. Unexpectedly, the effect of APB could not be mimicked by application of Sp-adenosine 3',5'-cyclic monophosphothioate triethylamine (Sp-cAMPS, 100-200 microM), a membrane-permeable analog of cyclic AMP (cAMP), or by pretreatment with forskolin (25 microM), an activator of adenylyl cyclase. The reduction in I(As) also was not blocked by pretreatment with the D1 receptor antagonist, R(+)-SCH23390 hydrochloride (SCH23390, 10-20 microM). In addition, intracellular dialysis with guanosine-5'-O-(2-thiodiphosphate (GDP-beta-S, 200 microM) did not preclude the APB-induced inhibition of I(As), nor did dialysis with guanosine-5'-O-(3-thiotriphosphate (GTP-gamma-S, 400 microM) prevent reversal of the effect. The effect of APB was produced by a reduction in the maximal conductance of I(As) without changing the voltage-dependence of the current. Collectively, these results argue that APB does not inhibit I(As) through D1 receptors coupled to stimulation of adenylyl cyclase, but rather by allosterically regulating or blocking the channels giving rise to this current.

Roles of Asp179 and Glu270 in ADP-Ribosylation of Actin by Clostridium perfringens Iota Toxin

PubMed Central

Belyy, Alexander; Tabakova, Irina; Lang, Alexander E.; Jank, Thomas; Belyi, Yury; Aktories, Klaus

2015-01-01

Clostridium perfringens iota toxin is a binary toxin composed of the enzymatically active component Ia and receptor binding component Ib. Ia is an ADP-ribosyltransferase, which modifies Arg177 of actin. The previously determined crystal structure of the actin-Ia complex suggested involvement of Asp179 of actin in the ADP-ribosylation reaction. To gain more insights into the structural requirements of actin to serve as a substrate for toxin-catalyzed ADP-ribosylation, we engineered Saccharomyces cerevisiae strains, in which wild type actin was replaced by actin variants with substitutions in residues located on the Ia-actin interface. Expression of the actin mutant Arg177Lys resulted in complete resistance towards Ia. Actin mutation of Asp179 did not change Ia-induced ADP-ribosylation and growth inhibition of S. cerevisiae. By contrast, substitution of Glu270 of actin inhibited the toxic action of Ia and the ADP-ribosylation of actin. In vitro transcribed/translated human β-actin confirmed the crucial role of Glu270 in ADP-ribosylation of actin by Ia. PMID:26713879

Recurrence risk of ictal asystole in epilepsy.

PubMed

Hampel, Kevin G; Thijs, Roland D; Elger, Christian E; Surges, Rainer

2017-08-22

To determine the recurrence risk of ictal asystole (IA) and its determining factors in people with epilepsy. We performed a systematic review of published cases with IA in 3 databases and additionally searched our local database for patients with multiple seizures simultaneously recorded with ECG and EEG and at least one IA. IA recurrence risk was estimated by including all seizures without knowledge of the chronological order. Various clinical features were assessed by an individual patient data meta-analysis. A random mixed effect logistic regression model was applied to estimate the average recurrence risk of IA. Plausibility of the calculated IA recurrence risk was checked by analyzing the local dataset with available information in chronological order. Eighty patients with 182 IA in 537 seizures were included. Recurrence risk of IA amounted to 40% (95% confidence interval [CI] 32%-50%). None of the clinical factors (age, sex, type and duration of epilepsy, hemispheric lateralization, duration of IA per patient) appeared to have a significant effect on the short-term recurrence risk of IA. When considering the local dataset only, IA recurrence risk was estimated to 30% (95% CI 14%-53%). Information whether IA coincided with symptoms (i.e., syncope) or not was given in 60 patients: 100 out of 142 IAs were symptomatic. Our data suggest that in case of clinically suspected IA, the recording of 1 or 2 seizures is not sufficient to rule out IA. Furthermore, the high short-term recurrence risk favors aggressive treatment, including pacemaker implantation if seizure freedom cannot be achieved. Copyright © 2017 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.

Association between childhood and adult attention deficit hyperactivity disorder symptoms in Korean young adults with Internet addiction.

PubMed

Kim, DongIll; Lee, Deokjong; Lee, Junghan; Namkoong, Kee; Jung, Young-Chul

2017-09-01

Background and aims Attention deficit hyperactivity disorder (ADHD) is one of the most common psychiatric comorbidities of Internet addiction (IA); however, the possible mechanisms that contribute to this high comorbidity are still under debate. This study aims to analyze these possible mechanisms by comparing the effect of IA severity and childhood ADHD on inattention, hyperactivity, and impulsivity in young adults with IA. We hypothesized that IA might have associations with ADHD-like cognitive and behavior symptoms aside from childhood ADHD. Methods Study participants consisted of 61 young male adults. Participants were administered a structured interview. The severity of IA, childhood and current ADHD symptoms, and psychiatry comorbid symptoms were assessed through self-rating scales. The associations between the severity of IA and ADHD symptoms were examined through hierarchical regression analyses. Results Hierarchical regression analyses showed that the severity of IA significantly predicted most dimensions of ADHD symptoms. By contrast, childhood ADHD predicted only one dimension. Discussion The high comorbidity of inattention and hyperactivity symptoms in IA should not solely be accounted by an independent ADHD disorder but should consider the possibility of cognitive symptoms related to IA. Functional and structural brain abnormalities associated with excessive and pathologic Internet usage might be related to these ADHD-like symptoms. Conclusion Inattention and hyperactivity in young adults with IA are more significantly associated with the severity of IA than that of childhood ADHD.

3'-UTR SNP rs2229611 in G6PC1 affects mRNA stability, expression and Glycogen Storage Disease type-Ia risk.

PubMed

Karthi, Sellamuthu; Rajeshwari, Mohan; Francis, Amirtharaj; Saravanan, Matheshwaran; Varalakshmi, Perumal; Houlden, Henry; Thangaraj, Kumarasamy; Ashokkumar, Balasubramaniem

2017-08-01

The frequency of rs2229611, previously reported in Chinese, Caucasians, Japanese and Hispanics, was investigated for the first time in Indian ethnicity. We analyzed its role in the progression of Glycogen Storage Disease type-Ia (GSD-Ia) and breast cancer. Genotype data on rs2229611 revealed that the risk of GSD-Ia was higher (P=0.0195) with CC compared to TT/TC genotypes, whereas no such correlation was observed with breast cancer cases. We observed a strong linkage disequilibrium (LD) among rs2229611 and other disease causing G6PC1 variants (|D'|=1, r 2 =1). Functional validation performed in HepG2 cells using luciferase constructs showed significant (P<0.05) decrease in expression than wild-type 3'-UTR due to curtailed mRNA stability. Furthermore, AU-rich elements (AREs) mediated regulation of G6PC1 expression characterized using 3'-UTR deletion constructs showed a prominent decrease in mRNA stability. We then examined whether miRNAs are involved in controlling G6PC1 expression using pmirGLO-UTR constructs, with evidence of more distinct inhibition in the reporter function with rs2229611. These data suggests that rs2229611 is a crucial regulatory SNP which in homozygous state leads to a more aggressive disease phenotype in GSD-Ia patients. The implication of this result is significant in predicting disease onset, progression and response to disease modifying treatments in patients with GSD-Ia. Copyright © 2017 Elsevier B.V. All rights reserved.

SALT spectroscopic classification of SN 2017erp as a type-Ia supernova well before maximum light

NASA Astrophysics Data System (ADS)

Jha, S. W.; Camacho, Y.; Dettman, K.; Pan, Y.-C.; Foley, R. J.; Rest, A.; Scolnic, D.; Skelton, R.

2017-06-01

We obtained SALT (+RSS) spectroscopy of SN 2017erp (discovered by K. Itagaki) on 2017 Jun 13.9 UT, covering the wavelength range 350-940 nm. Cross-correlation of the supernova spectrum with a template library using SNID (Blondin & Tonry 2007, ApJ, 666, 1024) shows SN 2017erp is a type-Ia supernova before maximum light.

Clinical and biochemical heterogeneity between patients with glycogen storage disease type IA: the added value of CUSUM for metabolic control.

PubMed

Peeks, Fabian; Steunenberg, Thomas A H; de Boer, Foekje; Rubio-Gozalbo, M Estela; Williams, Monique; Burghard, Rob; Rajas, Fabienne; Oosterveer, Maaike H; Weinstein, David A; Derks, Terry G J

2017-09-01

To study heterogeneity between patients with glycogen storage disease type Ia (GSD Ia), a rare inherited disorder of carbohydrate metabolism caused by the deficiency of glucose-6-phosphatase (G6Pase). Descriptive retrospective study of longitudinal clinical and biochemical data and long-term complications in 20 GSD Ia patients. We included 11 patients with homozygous G6PC mutations and siblings from four families carrying identical G6PC genotypes. To display subtle variations for repeated triglyceride measurements with respect to time for individual patients, CUSUM-analysis graphs were constructed. Patients with different homozygous G6PC mutations showed important differences in height, BMI, and biochemical parameters (i.e., lactate, uric acid, triglyceride, and cholesterol concentrations). Furthermore, CUSUM-analysis predicts and displays subtle changes in longitudinal blood triglyceride concentrations. Siblings in families also displayed important differences in biochemical parameters (i.e., lactate, uric acid, triglycerides, and cholesterol concentrations) and long-term complications (i.e., liver adenomas, nephropathy, and osteopenia/osteoporosis). Differences between GSD Ia patients reflect large clinical and biochemical heterogeneity. Heterogeneity between GSD Ia patients with homozygous G6PC mutations indicate an important role of the G6PC genotype/mutations. Differences between affected siblings suggest an additional role (genetic and/or environmental) of modifying factors defining the GSD Ia phenotype. CUSUM-analysis can facilitate single-patient monitoring of metabolic control and future application of this method may improve precision medicine for patients both with GSD and remaining inherited metabolic diseases.

Interstitial telomere-like repeats in the Arabidopsis thaliana genome.

PubMed

Uchida, Wakana; Matsunaga, Sachihiro; Sugiyama, Ryuji; Kawano, Shigeyuki

2002-02-01

Eukaryotic chromosomal ends are protected by telomeres, which are thought to play an important role in ensuring the complete replication of chromosomes. On the other hand, non-functional telomere-like repeats in the interchromosomal regions (interstitial telomeric repeats; ITRs) have been reported in several eukaryotes. In this study, we identified eight ITRs in the Arabidopsis thaliana genome, each consisting of complete and degenerate 300- to 1200-bp sequences. The ITRs were grouped into three classes (class IA-B, class II, and class IIIA-E) based on the degeneracy of the telomeric repeats in ITRs. The telomeric repeats of the two ITRs in class I were conserved for the most part, whereas the single ITR in class II, and the five ITRs in class III were relatively degenerated. In addition, degenerate ITRs were surrounded by common sequences that shared 70-100% homology to each other; these are named ITR-adjacent sequences (IAS). Although the genomic regions around ITRs in class I lacked IAS, those around ITRs in class II contained IAS (IASa), and those around five ITRs in class III had nine types of IAS (IASb, c, d, e, f, g, h, i, and j). Ten IAS types in classes II and III showed no significant homology to each other. The chromosomal locations of ITRs and IAS were not category-related, but most of them were adjacent to, or part of, a centromere. These results show that the A. thaliana genome has undergone chromosomal rearrangements, such as end-fusions and segmental duplications.

Using late-time optical and near-infrared spectra to constrain Type Ia supernova explosion properties

NASA Astrophysics Data System (ADS)

Maguire, K.; Sim, S. A.; Shingles, L.; Spyromilio, J.; Jerkstrand, A.; Sullivan, M.; Chen, T.-W.; Cartier, R.; Dimitriadis, G.; Frohmaier, C.; Galbany, L.; Gutiérrez, C. P.; Hosseinzadeh, G.; Howell, D. A.; Inserra, C.; Rudy, R.; Sollerman, J.

2018-03-01

The late-time spectra of Type Ia supernovae (SNe Ia) are powerful probes of the underlying physics of their explosions. We investigate the late-time optical and near-infrared spectra of seven SNe Ia obtained at the VLT with XShooter at >200 d after explosion. At these epochs, the inner Fe-rich ejecta can be studied. We use a line-fitting analysis to determine the relative line fluxes, velocity shifts, and line widths of prominent features contributing to the spectra ([Fe II], [Ni II], and [Co III]). By focussing on [Fe II] and [Ni II] emission lines in the ˜7000-7500 Å region of the spectrum, we find that the ratio of stable [Ni II] to mainly radioactively-produced [Fe II] for most SNe Ia in the sample is consistent with Chandrasekhar-mass delayed-detonation explosion models, as well as sub-Chandrasekhar mass explosions that have metallicity values above solar. The mean measured Ni/Fe abundance of our sample is consistent with the solar value. The more highly ionised [Co III] emission lines are found to be more centrally located in the ejecta and have broader lines than the [Fe II] and [Ni II] features. Our analysis also strengthens previous results that SNe Ia with higher Si II velocities at maximum light preferentially display blueshifted [Fe II] 7155 Å lines at late times. Our combined results lead us to speculate that the majority of normal SN Ia explosions produce ejecta distributions that deviate significantly from spherical symmetry.

Lymphocytes influence intracranial aneurysm formation and rupture: role of extracellular matrix remodeling and phenotypic modulation of vascular smooth muscle cells.

PubMed

Sawyer, David M; Pace, Lauren A; Pascale, Crissey L; Kutchin, Alexander C; O'Neill, Brannan E; Starke, Robert M; Dumont, Aaron S

2016-07-14

Intracranial aneurysms (IA) are increasingly recognized as a disease driven by chronic inflammation. Recent research has identified key mediators and processes underlying IA pathogenesis, but mechanistic understanding remains incomplete. Lymphocytic infiltrates have been demonstrated in patient IA tissue specimens and have also been shown to play an important role in abdominal aortic aneurysms (AAA) and related diseases such as atherosclerosis. However, no study has systematically examined the contribution of lymphocytes in a model of IA. Lymphocyte-deficient (Rag1) and wild-type (WT; C57BL/6 strain) mice were subjected to a robust IA induction protocol. Rates of IA formation and rupture were measured, and cerebral artery tissue was collected and utilized for histology and gene expression analysis. At 2 weeks, the Rag1 group had significantly fewer IA formations and ruptures than the WT group. Histological analysis of unruptured IA tissue showed robust B and T lymphocyte infiltration in the WT group, while there were no differences in macrophage infiltration, IA diameter, and wall thickness. Significant differences in interleukin-6 (IL-6), matrix metalloproteinases 2 (MMP2) and 9 (MMP9), and smooth muscle myosin heavy chain (MHC) were observed between the groups. Lymphocytes are key contributors to IA pathogenesis and provide a novel target for the prevention of IA progression and rupture in patients.

The curious case of SN 2011dn: A very peculiar type Ia supernova?

NASA Astrophysics Data System (ADS)

Rachubo, Alisa

Type Ia supernovae (SNe Ia) are excellent cosmological distance indicators due to the uniformity in their light curves, which led to the major discovery of the accelerated expansion of the universe. However, SNe Ia are not so uniform as one may expect, as there are many peculiar SNe Ia that exhibit differences in their photometric and spectroscopic behavior from normal SNe Ia. One of the goals of supernova cosmology today is to produce a cleaner sample of SNe Ia without these peculiar SNe Ia. Here we consider SN 2011dn, a peculiar SN Ia candidate. In 2011, Salvo, et al. carried out a preliminary analysis of a subset of the data prescribed here, and identified spectral and photometric peculiarities in this object's evolution that warranted further analysis. Here, we present a complete re-reduction and reanalysis of B, V,R, and I photometry of SN 2011dn obtained at Mount Laguna Observatory, spanning from 7 days before maximum light in B to 88 days past maximum light. In addition, we also consider total flux spectra from 9 days before maximum light to 4 days after maximum light, along with ultraviolet (UV) photometry obtained with the Swift telescope. From SN 2011dn's optical spectra, we find that SN 2011dn most closely resembles a SN 1991T-like type Ia supernova ('91T-like SN Ia). Such SNe Ia are typically more luminous than normal SNe Ia, and possess broader (i.e., they decline less rapidly than normal from maximum light) light curves. Their Deltam15(B) (drop in B magnitude 15 days after maximum light) are typically significantly less than the canonical value of 1.1, and can be as low as 0.8. In the earlier preliminary analysis, Salvo et al. measured a surprisingly high Deltam15(B) value for SN 2011dn, of ˜ 1.1. Since SN 2011dn was embedded in UGC 11501 (its host galaxy), however, it is possible that some of the light from the host galaxy was included in the photometric aperture, resulting in inaccurate photometric measurements. Here, in order to better isolate the supernova light from its host galaxy, we employ galaxy-subtraction techniques to generate more precise light curves. From these data, we obtain an updated Deltam15( B) value of 1.01 +/- 0.02, which suggests that SN 2011dn is indeed slightly overluminous compared to normal SNe Ia, but perhaps not as overluminous as '91T-like SNe Ia. However, despite this apparent resolution of the spectral and photometric conflict, we find SN 2011dn to still exhibit some unique features. For instance, its near-maximum and especially its post-maximum spectra exhibit an unusually weak Si II lambda6355 feature, even considering that '91T-like SNe Ia spectra tend to have shallow silicon features. Furthermore, we find that SN 2011dn exhibits some unusual UV-optical color evolution, though its early-time UV excess may be linked to unburned carbon in SN 2011dn's ejecta, as indicated by the C III lambda4649 feature in its pre-maximum spectra. Altogether, after a careful reanalysis of the spectral and photometric properties of SN 2011dn, we classify it as slightly overluminous, with '91T-like pre-maximum and near-maximum spectra, but exhibiting some atypical features. SN 2011dn is not as peculiar as anticipated, but still has some characteristics that are unique to it.

Systemic administration of anti-NGF increases A-type potassium currents and decreases pancreatic nociceptor excitability in a rat model of chronic pancreatitis.

PubMed

Zhu, Yaohui; Mehta, Kshama; Li, Cuiping; Xu, Guang-Yin; Liu, Liansheng; Colak, Tugba; Shenoy, Mohan; Pasricha, Pankaj Jay

2012-01-01

We have previously shown that pancreatic sensory neurons in rats with chronic pancreatitis (CP) display increased excitability associated with a decrease in transient inactivating potassium currents (I(A)), thus accounting in part for the hyperalgesia associated with this condition. Because of its well known role in somatic hyperalgesia, we hypothesized a role for the nerve growth factor (NGF) in driving these changes. CP was induced by intraductal injection of trinitrobenzene sulfonic acid (TNBS) in rats. After 3 wk, anti-NGF antibody or control serum was injected intra-peritoneally daily for 1 wk. This protocol was repeated in another set of experiments in control rats (receiving intraductal PBS instead of TNBS). Pancreatic nociceptors labeled with the dye Dil were identified, and patch-clamp recordings were made from acutely dissociated DRG neurons. Sensory neurons from anti-NGF-treated rats displayed a lower resting membrane potential, increased rheobase, decreased burst discharges in response to stimulatory current, and decreased input resistance compared with those treated with control serum. Under voltage-clamp condition, neuronal I(A) density was increased in anti-NGF-treated rats compared with rats treated with control serum. However, anti-NGF treatment had no effect on electrophysiological parameters in neurons from control rats. The expression of Kv-associated channel or ancillary genes Kv1.4, 4.1, 4.2, 4.3, and DPP6, DPP10, and KCHIPs 1-4 in pancreas-specific nociceptors was examined by laser-capture microdissection and real-time PCR quantification of mRNA levels. No significant differences were seen among those. These findings emphasize a key role for NGF in maintaining neuronal excitability in CP specifically via downregulation of I(A) by as yet unknown mechanisms.

The Carnegie–Chicago Hubble Program. III. The Distance to NGC 1365 via the Tip of the Red Giant Branch

NASA Astrophysics Data System (ADS)

Jang, In Sung; Hatt, Dylan; Beaton, Rachael L.; Lee, Myung Gyoon; Freedman, Wendy L.; Madore, Barry F.; Hoyt, Taylor J.; Monson, Andrew J.; Rich, Jeffrey A.; Scowcroft, Victoria; Seibert, Mark

2018-01-01

The Carnegie–Chicago Hubble Program (CCHP) seeks to anchor the distance scale of Type Ia supernovae via the Tip of the Red Giant Branch (TRGB) method. Based on deep Hubble Space Telescope ACS/WFC imaging, we present an analysis of the TRGB for the metal-poor halo of NGC 1365, a giant spiral galaxy in the Fornax cluster that was host to the Type Ia supernova SN 2012fr. We have measured the extinction-corrected TRGB magnitude of NGC 1365 to be F814W = 27.34 ± 0.03stat ± 0.04sys mag. In advance of future direct calibration by Gaia, we adopt a provisional I-band TRGB luminosity set at the Large Magellanic Cloud and find a true distance modulus μ 0 = 31.29 ± 0.04stat ± 0.06sys mag or D = 18.1 ± 0.3stat ± 0.5sys Mpc. This measurement is in excellent agreement with recent Cepheid-based distances to NGC 1365 and reveals no significant difference in the distances derived from stars of Populations I and II for this galaxy. We revisit the error budget for the CCHP path to the Hubble constant based on the analysis presented here, i.e., that for one of the most distant Type Ia supernova hosts within our Program, and find that a 2.5% measurement is feasible with the current sample of galaxies and TRGB absolute calibration. Based in part on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program #13691.

Luminous Supersoft X-Ray Sources as Progenitors of Type Ia Supernovae

NASA Technical Reports Server (NTRS)

DiStefano, R.

1996-01-01

In some luminous supersoft X-ray sources, hydrogen accretes onto the surface of a white dwarf at rates more-or-less compatible with steady nuclear burning. The white dwarfs in these systems therefore have a good chance to grow in mass. Here we review what is known about the rate of Type la supernovae that may be associated with SSSS. Observable consequences of the conjecture that SSSs can be progenitors of Type Ia supernovae are also discussed.

Characterization of the Enzymatic Component of Clostridium perfringens Iota-Toxin

PubMed Central

Nagahama, Masahiro; Sakaguchi, Yoshihiko; Kobayashi, Keiko; Ochi, Sadayuki; Sakurai, Jun

2000-01-01

The iotaa component (ia) of Clostridium perfringens ADP ribosylates nonmuscle β/γ actin and skeletal muscle α-actin. Replacement of Arg-295 in ia with alanine led to a complete loss of NAD+-glycohydrolase (NADase) and ADP-ribosyltransferase (ARTase); that of the residue with lysine caused a drastic reduction in NADase and ARTase activities (<0.1% of the wild-type activities) but did not completely diminish them. Substitution of alanine for Glu-378 and Glu-380 caused a complete loss of NADase and ARTase. However, exchange of Glu-378 to aspartic acid or glutamine resulted in little effect on NADase activity but a drastic reduction in ARTase activity (<0.1% of the wild-type activity). Exchange of Glu-380 to aspartic acid caused a drastic reduction in NADase and ARTase activities (<0.1% of the wild-type activities) but did not completely diminish them; that of the residue to glutamine caused a complete loss of ARTase activity. Replacement of Ser-338 with alanine resulted in 0.7 to 2.3% wild-type activities, and that of Ser-340 and Thr-339 caused a reduction in these activities of 5 to 30% wild-type activities. The kinetic analysis showed that Arg-295 and Ser-338 also play an important role in the binding of NAD+ to ia, that Arg-295, Glu-380, and Ser-338 play a crucial role in the catalytic rate of NADase activity, and that these three amino acid residues and Glu-378 are essential for ARTase activity. The effect of amino acid replacement in ia on ARTase activity was similar to that on lethal and cytotoxic activities, suggesting that lethal and cytotoxic activities in ia are dependent on ARTase activity. PMID:10735850

Internal robustness: systematic search for systematic bias in SN Ia data

NASA Astrophysics Data System (ADS)

Amendola, Luca; Marra, Valerio; Quartin, Miguel

2013-04-01

A great deal of effort is currently being devoted to understanding, estimating and removing systematic errors in cosmological data. In the particular case of Type Ia supernovae, systematics are starting to dominate the error budget. Here we propose a Bayesian tool for carrying out a systematic search for systematic contamination. This serves as an extension to the standard goodness-of-fit tests and allows not only to cross-check raw or processed data for the presence of systematics but also to pin-point the data that are most likely contaminated. We successfully test our tool with mock catalogues and conclude that the Union2.1 data do not possess a significant amount of systematics. Finally, we show that if one includes in Union2.1 the supernovae that originally failed the quality cuts, our tool signals the presence of systematics at over 3.8σ confidence level.

The interplay of seven subthreshold conductances controls the resting membrane potential and the oscillatory behavior of thalamocortical neurons

PubMed Central

Zagha, Edward; Mato, German; Rudy, Bernardo; Nadal, Marcela S.

2014-01-01

The signaling properties of thalamocortical (TC) neurons depend on the diversity of ion conductance mechanisms that underlie their rich membrane behavior at subthreshold potentials. Using patch-clamp recordings of TC neurons in brain slices from mice and a realistic conductance-based computational model, we characterized seven subthreshold ion currents of TC neurons and quantified their individual contributions to the total steady-state conductance at levels below tonic firing threshold. We then used the TC neuron model to show that the resting membrane potential results from the interplay of several inward and outward currents over a background provided by the potassium and sodium leak currents. The steady-state conductances of depolarizing Ih (hyperpolarization-activated cationic current), IT (low-threshold calcium current), and INaP (persistent sodium current) move the membrane potential away from the reversal potential of the leak conductances. This depolarization is counteracted in turn by the hyperpolarizing steady-state current of IA (fast transient A-type potassium current) and IKir (inwardly rectifying potassium current). Using the computational model, we have shown that single parameter variations compatible with physiological or pathological modulation promote burst firing periodicity. The balance between three amplifying variables (activation of IT, activation of INaP, and activation of IKir) and three recovering variables (inactivation of IT, activation of IA, and activation of Ih) determines the propensity, or lack thereof, of repetitive burst firing of TC neurons. We also have determined the specific roles that each of these variables have during the intrinsic oscillation. PMID:24760784

Polarization as a probe of dusty environments around Type Ia supernovae: radiative transfer models for SN 2012dn

NASA Astrophysics Data System (ADS)

Nagao, Takashi; Maeda, Keiichi; Yamanaka, Masayuki

2018-06-01

The geometry of the circumstellar (CS) medium around supernovae (SNe) provides important diagnostics to understand the nature of their progenitors. In this article, the properties of CS dust around SN 2012dn, a super-Chandrasekhar candidate Type Ia supernova (SC-SN), have been studied through detailed three-dimensional radiation transfer simulations. Using the detected near-infrared excess from SN 2012dn, we show that it has a disc-like dusty CS environment, the mass of which is roughly consistent with a branch of an accreting white dwarf system (the single degenerate scenario). We show that a similar system should produce polarization signals up to ˜8 per cent in the B band, depending on the viewing direction if polarimetric observations are performed. We predict that maximum polarization is reached around ˜60 d after the B-band maximum. We show that the temporal and wavelength dependence of the polarization signals, together with other unique features, can be easily distinguished from the interstellar polarization and intrinsic SN polarization. Indeed, the small polarization degree observed for normal Type Ia SNe (SNe Ia) can constrain a parameter space in CS dust mass and distribution. We thus encourage multi-band polarimetric observations for SNe Ia, especially for outliers including SC-SNe, for which some arguments for the single degenerate scenario exist but polarization data are very rare so far.

Interoception in insula subregions as a possible state marker for depression—an exploratory fMRI study investigating healthy, depressed and remitted participants

PubMed Central

Wiebking, Christine; de Greck, Moritz; Duncan, Niall W.; Tempelmann, Claus; Bajbouj, Malek; Northoff, Georg

2015-01-01

Background: Interoceptive awareness (iA), the awareness of stimuli originating inside the body, plays an important role in human emotions and psychopathology. The insula is particularly involved in neural processes underlying iA. However, iA-related neural activity in the insula during the acute state of major depressive disorder (MDD) and in remission from depression has not been explored. Methods: A well-established fMRI paradigm for studying (iA; heartbeat counting) and exteroceptive awareness (eA; tone counting) was used. Study participants formed three independent groups: patients suffering from MDD, patients in remission from MDD or healthy controls. Task-induced neural activity in three functional subdivisions of the insula was compared between these groups. Results: Depressed participants showed neural hypo-responses during iA in anterior insula regions, as compared to both healthy and remitted participants. The right dorsal anterior insula showed the strongest response to iA across all participant groups. In depressed participants there was no differentiation between different stimuli types in this region (i.e., between iA, eA and noTask). Healthy and remitted participants in contrast showed clear activity differences. Conclusions: This is the first study comparing iA and eA-related activity in the insula in depressed participants to that in healthy and remitted individuals. The preliminary results suggest that these groups differ in there being hypo-responses across insula regions in the depressed participants, whilst non-psychiatric participants and patients in remission from MDD show the same neural activity during iA in insula subregions implying a possible state marker for MDD. The lack of activity differences between different stimulus types in the depressed group may account for their symptoms of altered external and internal focus. PMID:25914633

Observations of SN 2015F Suggest a Correlation between the Intrinsic Luminosity of Type Ia Supernovae and the Shape of Their Light Curves >900 Days after Explosion

NASA Astrophysics Data System (ADS)

Graur, Or; Zurek, David R.; Rest, Armin; Seitenzahl, Ivo R.; Shappee, Benjamin J.; Fisher, Robert; Guillochon, James; Shara, Michael M.; Riess, Adam G.

2018-06-01

The late-time light curves of Type Ia supernovae (SNe Ia), observed >900 days after explosion, present the possibility of a new diagnostic for SN Ia progenitor and explosion models. First, however, we must discover what physical process (or processes) leads to the slow-down of the light curve relative to a pure 56Co decay, as observed in SNe 2011fe, 2012cg, and 2014J. We present Hubble Space Telescope observations of SN 2015F, taken ≈600–1040 days past maximum light. Unlike those of the three other SNe Ia, the light curve of SN 2015F remains consistent with being powered solely by the radioactive decay of 56Co. We fit the light curves of these four SNe Ia in a consistent manner and measure possible correlations between the light-curve stretch—a proxy for the intrinsic luminosity of the SN—and the parameters of the physical model used in the fit. We propose a new, late-time Phillips-like correlation between the stretch of the SNe and the shape of their late-time light curves, which we parameterize as the difference between their pseudo-bolometric luminosities at 600 and 900 days: ΔL 900 = log(L 600/L 900). Our analysis is based on only four SNe, so a larger sample is required to test the validity of this correlation. If true, this model-independent correlation provides a new way to test which physical process lies behind the slow-down of SN Ia light curves >900 days after explosion, and, ultimately, fresh constraints on the various SN Ia progenitor and explosion models.

Reddened, Redshifted, or Intrinsically Red? Understanding Near-ultraviolet Colors of Type Ia Supernovae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Peter J.; Landez, Nancy J.; Milne, Peter A.

The intrinsic colors of Type Ia supernovae (SNe Ia) are important to understanding their use as cosmological standard candles. Understanding the effects of reddening and redshift on the observed colors are complicated and dependent on the intrinsic spectrum, the filter curves, and the wavelength dependence of reddening. We present ultraviolet and optical data of a growing sample of SNe Ia observed with the Ultraviolet/Optical Telescope on the Swift spacecraft and use this sample to re-examine the near-UV (NUV) colors of SNe Ia. We find that a small amount of reddening ( E ( B − V ) = 0.2 mag)more » could account for the difference between groups designated as NUV-blue and NUV-red, and a moderate amount of reddening ( E ( B − V ) = 0.5 mag) could account for the whole NUV-optical differences. The reddening scenario, however, is inconsistent with the mid-UV colors and color evolution. The effect of redshift alone only accounts for part of the variation. Using a spectral template of SN2011fe, we can forward model the effects of redshift and reddening and directly compare those with the observed colors. We find that some SNe are consistent with reddened versions of SN2011fe, but most SNe Ia are much redder in the uvw 1 − v color than SN2011fe reddened to the same b − v color. The absolute magnitudes show that two out of five NUV-blue SNe Ia are blue because their near-UV luminosity is high, and the other three are optically fainter. We also show that SN 2011fe is not a “normal” SN Ia in the UV, but has colors placing it at the blue extreme of our sample.« less

Type Ia supernovae with and without blueshifted narrow Na I D lines - how different is their structure?

NASA Astrophysics Data System (ADS)

Hachinger, S.; Röpke, F. K.; Mazzali, P. A.; Gal-Yam, A.; Maguire, K.; Sullivan, M.; Taubenberger, S.; Ashall, C.; Campbell, H.; Elias-Rosa, N.; Feindt, U.; Greggio, L.; Inserra, C.; Miluzio, M.; Smartt, S. J.; Young, D.

2017-10-01

In studies on intermediate- and high-resolution spectra of Type Ia supernovae (SNe Ia), some objects exhibit narrow Na I D absorptions often blueshifted with respect to the rest wavelength within the host galaxy. The absence of these in other SNe Ia may reflect that the explosions have different progenitors: blueshifted Na I D features might be explained by the outflows of 'single-degenerate' systems (binaries of a white dwarf with a non-degenerate companion). In this work, we search for systematic differences among SNe Ia for which the Na I D characteristics have been clearly established in previous studies. We perform an analysis of the chemical abundances in the outer ejecta of 13 'spectroscopically normal' SNe Ia (five of which show blueshifted Na lines), modelling time series of photospheric spectra with a radiative-transfer code. We find only moderate differences between 'blueshifted-Na', 'redshifted-Na' and 'no-Na' SNe Ia, so that we can neither conclusively confirm a 'one-scenario' nor a 'two-scenario' theory for normal SNe Ia. Yet, some of the trends we see should be further studied using larger observed samples: models for blueshifted-Na SNe tend to show higher photospheric velocities than no-Na SNe, corresponding to a higher opacity of the envelope. Consistently, blueshifted-Na SNe show hints of a somewhat larger iron-group content in the outer layers with respect to the no-Na subsample (and also to the redshifted-Na subsample). This agrees with earlier work where it was found that the light curves of no-Na SNe - often appearing in elliptical galaxies - are narrower, that is, decline more rapidly.

Stroke in Indigenous Africans, African Americans and European Americans: Interplay of racial and geographic factors

PubMed Central

Owolabi, Mayowa; Sarfo, Fred; Howard, Virginia J.; Irvin, Marguerite R; Gebregziabher, Mulugeta; Akinyemi, Rufus; Bennett, Aleena; Armstrong, Kevin; Tiwari, Hemant K.; Akpalu, Albert; Wahab, Kolawole W.; Owolabi, Lukman; Fawale, Bimbo; Komolafe, Morenikeji; Obiako, Reginald; Adebayo, Philip; Manly, Jennifer M; Ogbole, Godwin; Melikam, Ezinne; Laryea, Ruth; Saulson, Raelle; Jenkins, Carolyn; Arnett, Donna K; Lackland, Daniel T; Ovbiagele, Bruce; Howard, George

2017-01-01

Background and Purpose The relative contributions of racial and geographic factors to higher risk of stroke in people of African ancestry have not been unraveled. We compared stroke type and contributions of vascular risk factors among indigenous Africans (IA), African Americans (AA) and European Americans (EA). Methods SIREN is a large multinational case-control study in West Africa - the ancestral home of 71% AA - whilst REGARDS is a cohort study including AA and EA in United States. Using harmonized assessments and standard definitions, we compared data on stroke type and established risk factors for stroke in acute stroke cases age ≥55 years in both studies. Results There were 811 IA, 452 AA and 665 EA stroke subjects, with mean age of 68.0±9.3, 73.0±8.3 and 76.0±8.3 years respectively (p<0.0001). Hemorrhagic stroke was more frequent among IA (27%) compared to AA (8%) and EA (5.4%; p < 0.001). Lacunar strokes were more prevalent in IA (47.1%), followed by AA (35.1%), and then EA (21.0%; p < 0.0001). The frequency of hypertension in decreasing order was IA (92.8%), followed by AA (82.5%) and then EA (64.2%; p<0.0001) and similarly for diabetes mellitus (DM) IA (38.3%), AA (36.8%) and EA (21.0 %; p<0.0001). Pre-morbid sedentary lifestyle was similar in AA (37.7%) and EA (34.0%) but lower frequency in IA (8.0%). Conclusion Environmental risk factors such as sedentary lifestyle may contribute to the higher proportion of ischemic stroke in AA compared to IA, while racial factors may contribute to the higher proportion of hypertension and DM among stroke subjects of African ancestry. PMID:28389611

Interoception in insula subregions as a possible state marker for depression-an exploratory fMRI study investigating healthy, depressed and remitted participants.

PubMed

Wiebking, Christine; de Greck, Moritz; Duncan, Niall W; Tempelmann, Claus; Bajbouj, Malek; Northoff, Georg

2015-01-01

Interoceptive awareness (iA), the awareness of stimuli originating inside the body, plays an important role in human emotions and psychopathology. The insula is particularly involved in neural processes underlying iA. However, iA-related neural activity in the insula during the acute state of major depressive disorder (MDD) and in remission from depression has not been explored. A well-established fMRI paradigm for studying (iA; heartbeat counting) and exteroceptive awareness (eA; tone counting) was used. Study participants formed three independent groups: patients suffering from MDD, patients in remission from MDD or healthy controls. Task-induced neural activity in three functional subdivisions of the insula was compared between these groups. Depressed participants showed neural hypo-responses during iA in anterior insula regions, as compared to both healthy and remitted participants. The right dorsal anterior insula showed the strongest response to iA across all participant groups. In depressed participants there was no differentiation between different stimuli types in this region (i.e., between iA, eA and noTask). Healthy and remitted participants in contrast showed clear activity differences. This is the first study comparing iA and eA-related activity in the insula in depressed participants to that in healthy and remitted individuals. The preliminary results suggest that these groups differ in there being hypo-responses across insula regions in the depressed participants, whilst non-psychiatric participants and patients in remission from MDD show the same neural activity during iA in insula subregions implying a possible state marker for MDD. The lack of activity differences between different stimulus types in the depressed group may account for their symptoms of altered external and internal focus.

Cognitive-Affective Correlates of Suicide Ideation and Attempt: Mindfulness is Negatively Associated with Suicide Attempt History but Not State Suicidality.

PubMed

Chesin, Megan; Cascardi, Michele

2018-06-11

To test whether three cognitive-affective correlates, mindfulness, emotion reactivity, and depressive symptom severity, have different associations with current suicidal ideation (SI), a history of suicide attempt (SA) and SA+SI among emerging adults. To test whether impulsive-aggression (IA) moderates associations between cognitive-affective correlates of suicidal behavior and suicidality. Survey data on current SI, SA history, mindfulness, emotion reactivity, depressive symptom severity, and IA were collected from 780 emerging adults. Results from multinomial logistic regression analysis showed greater depressive symptom severity among emerging adults with current SI, regardless of SA history. Those with a history of SA reported greater depressive symptom severity and less mindfulness than controls. IA did not moderate relationships of SI and/or SA and mindfulness, emotion reactivity, or depressive symptom severity. Mindfulness is a marker of SA, and depressive symptom severity is associated with current SI and SA history in emerging adults. IA does not moderate these associations. To the extent that a history of SA is indicative of elevated trait-like suicide risk and SI indicates state suicidality, our findings suggest that mindfulness protects against longer-term vulnerability to SA while depressive symptom severity increases with increasing suicide state-trait risk.

Immunophenotypes of macular corneal dystrophy in India and correlation with mutations in CHST6.

PubMed

Sultana, Afia; Klintworth, Gordon K; Thonar, Eugene J-M A; Vemuganti, Geeta K; Kannabiran, Chitra

2009-01-01

To determine the immunophenotypes of macular corneal dystrophy (MCD) in Indian patients and to correlate them with mutations in the carbohydrate 6-sulfotransferase (CHST6) gene. Sixty-four patients from 53 families with MCD that were previously screened for mutations in CHST6 were included in an immunophenotype analysis. Antigenic keratan sulfate (AgKS) in serum as well as corneal tissue was evaluated in 31 families. Only cornea was evaluated in 11 families, and only serum was evaluated in 11 families. AgKS was detected in formalin-fixed, paraffin-embedded corneal sections by immunohistochemistry and in serum by ELISA using a monoclonal antibody against sulfated forms of KS in patients with MCD as well as normal controls. Analysis of corneal and/or serum AgKS disclosed MCD type I (27 families), MCD type IA (5 families), and MCD type II (3 families) in the cases studied. An additional 10 families were either MCD type I or MCD type IA since only serum AgKS data were available. Seven families manifested atypical immunophenotypes since the corneal AgKS expression was either of MCD type I or MCD type IA, but serum AgKS levels ranged from 19 ng/ml to 388 ng/ml. More than one immunophenotype was detected amongst siblings in two families. Each immunophenotype was associated with mutational heterogeneity in CHST6. MCD type I was the predominant immunophenotype in the Indian population studied followed by MCD type IA and then MCD type II. We detected further immunophenotypic heterogeneity by finding atypical patterns of AgKS reactivity in a subset of families. There were no simple correlations between immunophenotypes and specific mutations in CHST6, suggesting that factors other than CHST6 mutations may be contributing to the immunophenotypes in MCD.

Spectroscopic Classification of ASASSN-16cu as a Type Ia SN

NASA Astrophysics Data System (ADS)

Strader, Jay; Chomiuk, Laura; Shishkovsky, Laura

2016-03-01

We obtained an optical spectrum of ASASSN-16cu (ATel #8796) on UT March 29.37 with the Goodman Spectrograph on the SOAR telescope. Classification with SNID (Blondin and Tonry 2007, ApJ, 666, 1024) indicates ASASSN-16cu is a normal Type Ia SN observed at about 70 days after peak. The redshift is consistent with proposed host galaxy IC 4723 (z=0.011128, via NED).

Ion-acoustic and electron-acoustic type nonlinear waves in dusty plasmas

NASA Astrophysics Data System (ADS)

Volosevich, A.-V.; Meister, C.-V.

2003-04-01

In the present work, two three-dimensional nonlinear theoretical models of electrostatic solitary waves are investigated within the frame of magnetohydrodynamics. Both times, a multi-component plasma is considered, which consists of hot electrons with a rather flexible distribution function, hot ions with Boltzmann-type distribution, and (negatively as well as positively charged) dust. Additionally, cold ion beams are taken into account in the model to study ion-acoustic structures (IAS), and cold electron beams are included into the model to investigate electron-acoustic structures (EAS). The numerical results of the considered theoretical models allow to make the following conclusions: 1) Electrostatic structures with negative potential (of rarefaction type) are formed both in the IAS model and in the EAS model, but structures with negative potential (of compressional type) are formed in the IAS model only. 2) The intervals of various plasma parameters (velocities of ion and electron beams, temperatures, densities of the plasma components, ions' masses), for which the existence of IAS and EAS solitary waves and structures is possible, are calculated. 3) Further, the parameters of the electrostatic structures (wave amplitudes, scales along and perpendicular to the magnetic field, velocities) are estimated. 4) The application of the present numerical simulation for multi-component plasmas to various astrophysical systems under different physical conditions is discussed.

ARSENIC AND THE EPIGENOME: LINKED BY METHYLATION(Thailand)

EPA Science Inventory

Inorganic arsenic (iAs) is an environmental toxicant currently poisoning millions of people worldwide. The most common route of As exposure in humans is through the consumption of drinking water contaminated with iAs from natural, geologic sources. Inorganic As exists in drinking...

Measuring the Hubble constant with Type Ia supernovae as near-infrared standard candles

NASA Astrophysics Data System (ADS)

Dhawan, Suhail; Jha, Saurabh W.; Leibundgut, Bruno

2018-01-01

The most precise local measurements of H0 rely on observations of Type Ia supernovae (SNe Ia) coupled with Cepheid distances to SN Ia host galaxies. Recent results have shown tension comparing H0 to the value inferred from CMB observations assuming ΛCDM, making it important to check for potential systematic uncertainties in either approach. To date, precise local H0 measurements have used SN Ia distances based on optical photometry, with corrections for light curve shape and colour. Here, we analyse SNe Ia as standard candles in the near-infrared (NIR), where luminosity variations in the supernovae and extinction by dust are both reduced relative to the optical. From a combined fit to 9 nearby calibrator SNe with host Cepheid distances from Riess et al. (2016) and 27 SNe in the Hubble flow, we estimate the absolute peak J magnitude MJ = -18.524 ± 0.041 mag and H0 = 72.8 ± 1.6 (statistical) ±2.7 (systematic) km s-1 Mpc-1. The 2.2% statistical uncertainty demonstrates that the NIR provides a compelling avenue to measuring SN Ia distances, and for our sample the intrinsic (unmodeled) peak J magnitude scatter is just 0.10 mag, even without light curve shape or colour corrections. Our results do not vary significantly with different sample selection criteria, though photometric calibration in the NIR may be a dominant systematic uncertainty. Our findings suggest that tension in the competing H0 distance ladders is likely not a result of supernova systematics that could be expected to vary between optical and NIR wavelengths, like dust extinction. We anticipate further improvements in H0 with a larger calibrator sample of SNe Ia with Cepheid distances, more Hubble flow SNe Ia with NIR light curves, and better use of the full NIR photometric data set beyond simply the peak J-band magnitude.

Metallicity Gradients in the Intracluster Gas of Abell 496

NASA Astrophysics Data System (ADS)

Dupke, Renato A.; White, Raymond E., III

2000-07-01

Analysis of spatially resolved ASCA spectra of the intracluster gas in Abell 496 confirms there are mild metal abundance enhancements near the center, as previously found in a joint analysis of spectra from Ginga Large Area Counter and Einstein solid state spectrometer. Simultaneous analysis of spectra from all ASCA instruments (SIS+GIS) shows that the iron abundance is 0.36+/-0.03 solar 3'-12' from the center of the cluster and rises ~50% to 0.53+/-0.04 solar within the central 2'. The F-test shows that this abundance gradient is significant at the more than 99.99% level. Nickel and sulfur abundances are also centrally enhanced. We use a variety of elemental abundance ratios to assess the relative contribution of Type Ia supernovae (SNe Ia) and Type II supernovae (SNe II) to the metal enrichment of the intracluster gas. We find spatial gradients in several abundance ratios, indicating that the fraction of iron from SNe Ia increases toward the cluster center, with SNe Ia accounting for ~50% of the iron mass 3'-12' from the center and ~70% within 2'. The increased proportion of SN Ia ejecta at the center is such that the central iron abundance enhancement can be attributed wholly to SNe Ia; we find no significant gradient in SN II ejecta. These spatial gradients in the proportion of SN Ia/II ejecta imply that the dominant metal enrichment mechanism near the center is different than in the outer parts of the cluster. We show that the central abundance enhancement is unlikely to be due to ram pressure stripping of gas from cluster galaxies or to secularly accumulated stellar mass loss within the central cD. We suggest that the additional SN Ia ejecta near the center is the vestige of a secondary SN Ia-driven wind from the cD (following a more energetic protogalactic SN II-driven wind phase), which was partially smothered in the cD due to its location at the cluster center.

Crystallization and preliminary crystallographic analysis of an aminoglycoside kinase from Legionella pneumophila

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lemke, Christopher T.; Hwang, Jiyoung; Xiong, Bing

2005-06-01

Two crystal forms of the antibiotic resistance enzyme APH(9)-Ia from L. pneumophila are reported. 9-Aminoglycoside phosphotransferase type Ia [APH(9)-Ia] is a resistance factor in Legionella pneuemophila, the causative agent of legionnaires’ disease. It is responsible for providing intrinsic resistance to the antibiotic spectinomycin. APH(9)-Ia phosphorylates one of the hydroxyl moieties of spectinomycin in an ATP-dependent manner, abolishing the antibiotic properties of this drug. Here, the crystallization and preliminary X-ray studies of this enzyme in two crystal forms is reported. One of the these crystal forms provides diffraction data to a resolution of 1.7 Å.

The severity of Internet addiction risk and its relationship with the severity of borderline personality features, childhood traumas, dissociative experiences, depression and anxiety symptoms among Turkish university students.

PubMed

Dalbudak, Ercan; Evren, Cuneyt; Aldemir, Secil; Evren, Bilge

2014-11-30

The aim of this study was to investigate the relationship of Internet addiction (IA) risk with the severity of borderline personality features, childhood traumas, dissociative experiences, depression and anxiety symptoms among Turkish university students. A total of 271 Turkish university students participated in this study. The students were assessed through the Internet Addiction Scale (IAS), the Borderline Personality Inventory (BPI), the Dissociative Experiences Scale (DES), the Childhood Trauma Questionnaire (CTQ-28), the Beck Depression Inventory (BDI) and the Beck Anxiety Inventory (BAI). The rates of students were 19.9% (n=54) in the high IA risk group, 38.7% (n=105) in the mild IA risk group and 41.3% (n=112) in the group without IA risk. Correlation analyses revealed that the severity of IA risk was related with BPI, DES, emotional abuse, CTQ-28, depression and anxiety scores. Univariate covariance analysis (ANCOVA) indicated that the severity of borderline personality features, emotional abuse, depression and anxiety symptoms were the predictors of IAS score, while gender had no effect on IAS score. Among childhood trauma types, emotional abuse seems to be the main predictor of IA risk severity. Borderline personality features predicted the severity of IA risk together with emotional abuse, depression and anxiety symptoms among Turkish university students. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Stable isotope-assisted NMR characterization of interaction between lipid A and sarcotoxin IA, a cecropin-type antibacterial peptide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yagi-Utsumi, Maho; Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603; Yamaguchi, Yoshiki

Highlights: ► Recombinant sarcotoxin IA was successfully produced with {sup 13}C- and {sup 15}N-labeling. ► Sarcotoxin IA adopts an N-terminal α-helix upon binding to lipid A-embedding micelles. ► Two lysine residues are involved in lipid A-mediated antibacterial activities. -- Abstract: Sarcotoxin IA is a 39-residue cecropin-type peptide from Sarcophaga peregrina. This peptide exhibits antibacterial activity against Gram-negative bacteria through its interaction with lipid A, a core component of lipopolysaccharides. To acquire detailed structural information on this specific interaction, we performed NMR analysis using bacterially expressed sarcotoxin IA analogs with {sup 13}C- and {sup 15}N-labeling along with lipid A-embedding micelles composedmore » of dodecylphosphocholine. By inspecting the stable isotope-assisted NMR data, we revealed that the N-terminal segment (Leu3–Arg18) of sarcotoxin IA formed an amphiphilic α-helix upon its interaction with the aqueous micelles. Furthermore, chemical shift perturbation data indicated that the amino acid residues displayed on this α-helix were involved in the specific interaction with lipid A. On the basis of these data, we successfully identified Lys4 and Lys5 as key residues in the interaction with lipid A and the consequent antibacterial activity. Therefore, these results provide unique information for designing chemotherapeutics based on antibacterial peptide structures.« less

Constraining the Type Ia Supernova Progenitor: The Search for Hydrogen in Nebular Spectra

NASA Astrophysics Data System (ADS)

Leonard, Douglas

2006-02-01

The progenitor systems of Type Ia supernovae (SNe Ia) are observationally unconstrained. Prevailing theory invokes a carbon- oxygen white dwarf accreting matter from a companion until a thermonuclear runaway ensues that incinerates the white dwarf. While models of exploding carbon-oxygen white dwarfs faithfully reproduce the main characteristics of SNe Ia, we are ignorant about the nature of the proposed companion star. Simulations resulting from this single- degenerate binary channel, however, demand the presence of low-velocity, H(alpha) emission in spectra taken in the nebular phase (250 - 400 days after maximum light), since a portion of the companion's envelope becomes entrained in the ejecta. This hydrogen has never been detected, and only generally weak limits have heretofore been set from ~ 6 SNe Ia observed during the nebular phase at low resolution and often with a low signal-to-noise ratio (S/N). We propose to remedy this situation through high S/N observations of two nearby, nebular-phase SNe Ia, with sufficient sensitivity and resolution to detect ~ 0.01 Msun of solar abundance material in the ejecta. The detection of late- time H(alpha) emission would be considered a ``smoking gun'' for the binary scenario. If H(alpha) is not detected, the limits will effectively rule out sub-giant, red giant, and all but the most widely separated main-sequence companions.

Evidence for Sub-Chandrasekhar Mass Type Ia Supernovae from an Extensive Survey of Radiative Transfer Models

NASA Astrophysics Data System (ADS)

Goldstein, Daniel A.; Kasen, Daniel

2018-01-01

There are two classes of viable progenitors for normal Type Ia supernovae (SNe Ia): systems in which a white dwarf explodes at the Chandrasekhar mass ({M}{ch}), and systems in which a white dwarf explodes below the Chandrasekhar mass (sub-{M}{ch}). It is not clear which of these channels is dominant; observations and light-curve modeling have provided evidence for both. Here we use an extensive grid of 4500 time-dependent, multiwavelength radiation transport simulations to show that the sub-{M}{ch} model can reproduce the entirety of the width–luminosity relation, while the {M}{ch} model can only produce the brighter events (0.8< {{Δ }}{M}15(B)< 1.55), implying that fast-declining SNe Ia come from sub-{M}{ch} explosions. We do not assume a particular theoretical paradigm for the progenitor or explosion mechanism, but instead construct parameterized models that vary the mass, kinetic energy, and compositional structure of the ejecta, thereby realizing a broad range of possible outcomes of white dwarf explosions. We provide fitting functions based on our large grid of detailed simulations that map observable properties of SNe Ia, such as peak brightness and light-curve width, to physical parameters such as {}56{Ni} and total ejected mass. These can be used to estimate the physical properties of observed SNe Ia.

Reading a Story: Different Degrees of Learning in Different Learning Environments.

PubMed

Giannini, Anna Maria; Cordellieri, Pierluigi; Piccardi, Laura

2017-01-01

The learning environment in which material is acquired may produce differences in delayed recall and in the elements that individuals focus on. These differences may appear even during development. In the present study, we compared three different learning environments in 450 normally developing 7-year-old children subdivided into three groups according to the type of learning environment. Specifically, children were asked to learn the same material shown in three different learning environments: reading illustrated books (TB); interacting with the same text displayed on a PC monitor and enriched with interactive activities (PC-IA); reading the same text on a PC monitor but not enriched with interactive narratives (PC-NoIA). Our results demonstrated that TB and PC-NoIA elicited better verbal memory recall. In contrast, PC-IA and PC-NoIA produced higher scores for visuo-spatial memory, enhancing memory for spatial relations, positions and colors with respect to TB. Interestingly, only TB seemed to produce a deeper comprehension of the story's moral. Our results indicated that PC-IA offered a different type of learning that favored visual details. In this sense, interactive activities demonstrate certain limitations, probably due to information overabundance, emotional mobilization, emphasis on images and effort exerted in interactive activities. Thus, interactive activities, although entertaining, act as disruptive elements which interfere with verbal memory and deep moral comprehension.

SDSS-II Supernova survey. An analysis of the largest sample of type IA supernovae and correlations with host-galaxy spectral properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wolf, Rachel C.; D’Andrea, Chris B.; Gupta, Ravi R.

2016-04-20

Using the largest single-survey sample of Type Ia supernovae (SNe Ia) to date, we study the relationship between properties of SNe Ia and those of their host galaxies, focusing primarily on correlations with Hubble residuals (HR). Our sample consists of 345 photometrically-classified or spectroscopicallyconfirmed SNe Ia discovered as part of the SDSS-II Supernova Survey (SDSS-SNS). This analysis utilizes host-galaxy spectroscopy obtained during the SDSS-I/II spectroscopic survey and from an ancillary program on the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS) that obtained spectra for nearly all host galaxies of SDSS-II SN candidates. In addition, we use photometric hostgalaxy properties from themore » SDSS-SNS data release (Sako et al. 2014) such as host stellar mass and star-formation rate. We confirm the well-known relation between HR and host-galaxy mass and find a 3.6σ significance of a non-zero linear slope. We also recover correlations between HR and hostgalaxy gas-phase metallicity and specific star-formation rate as they are reported in the literature. With our large dataset, we examine correlations between HR and multiple host-galaxy properties simultaneously and find no evidence of a significant correlation. We also independently analyze our spectroscopically-confirmed and photometrically-classified SNe Ia and comment on the significance of similar combined datasets for future surveys.« less

SDSS-II SUPERNOVA SURVEY: AN ANALYSIS OF THE LARGEST SAMPLE OF TYPE IA SUPERNOVAE AND CORRELATIONS WITH HOST-GALAXY SPECTRAL PROPERTIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wolf, Rachel C.; Gupta, Ravi R.; Sako, Masao

2016-04-20

Using the largest single-survey sample of Type Ia supernovae (SNe Ia) to date, we study the relationship between properties of SNe Ia and those of their host galaxies, focusing primarily on correlations with Hubble residuals (HRs). Our sample consists of 345 photometrically classified or spectroscopically confirmed SNe Ia discovered as part of the SDSS-II Supernova Survey (SDSS-SNS). This analysis utilizes host-galaxy spectroscopy obtained during the SDSS-I/II spectroscopic survey and from an ancillary program on the SDSS-III Baryon Oscillation Spectroscopic Survey that obtained spectra for nearly all host galaxies of SDSS-II SN candidates. In addition, we use photometric host-galaxy properties frommore » the SDSS-SNS data release such as host stellar mass and star formation rate. We confirm the well-known relation between HR and host-galaxy mass and find a 3.6 σ significance of a nonzero linear slope. We also recover correlations between HR and host-galaxy gas-phase metallicity and specific star formation rate as they are reported in the literature. With our large data set, we examine correlations between HR and multiple host-galaxy properties simultaneously and find no evidence of a significant correlation. We also independently analyze our spectroscopically confirmed and photometrically classified SNe Ia and comment on the significance of similar combined data sets for future surveys.« less

The pathogenesis shared between abdominal aortic aneurysms and intracranial aneurysms: a microarray analysis.

PubMed

Wang, Wen; Li, Hao; Zhao, Zheng; Wang, Haoyuan; Zhang, Dong; Zhang, Yan; Lan, Qing; Wang, Jiangfei; Cao, Yong; Zhao, Jizong

2018-04-01

Abdominal aortic aneurysms (AAAs) and intracranial saccular aneurysms (IAs) are the most common types of aneurysms. This study was to investigate the common pathogenesis shared between these two kinds of aneurysms. We collected 12 IAs samples and 12 control arteries from the Beijing Tiantan Hospital and performed microarray analysis. In addition, we utilized the microarray datasets of IAs and AAAs from the Gene Expression Omnibus (GEO), in combination with our microarray results, to generate messenger RNA expression profiles for both AAAs and IAs in our study. Functional exploration and protein-protein interaction (PPI) analysis were performed. A total of 727 common genes were differentially expressed (404 was upregulated; 323 was downregulated) for both AAAs and IAs. The GO and pathway analyses showed that the common dysregulated genes were mainly enriched in vascular smooth muscle contraction, muscle contraction, immune response, defense response, cell activation, IL-6 signaling and chemokine signaling pathways, etc. The further protein-protein analysis identified 35 hub nodes, including TNF, IL6, MAPK13, and CCL5. These hub node genes were enriched in inflammatory response, positive regulation of IL-6 production, chemokine signaling pathway, and T/B cell receptor signaling pathway. Our study will gain new insight into the molecular mechanisms for the pathogenesis of both types of aneurysms and provide new therapeutic targets for the patients harboring AAAs and IAs.

NORMAL TYPE Ia SUPERNOVAE FROM VIOLENT MERGERS OF WHITE DWARF BINARIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pakmor, R.; Kromer, M.; Taubenberger, S.

2012-03-15

One of the most important questions regarding the progenitor systems of Type Ia supernovae (SNe Ia) is whether mergers of two white dwarfs can lead to explosions that reproduce observations of normal events. Here we present a fully three-dimensional simulation of a violent merger of two carbon-oxygen white dwarfs with masses of 0.9 M{sub Sun} and 1.1 M{sub Sun} combining very high resolution and exact initial conditions. A well-tested combination of codes is used to study the system. We start with the dynamical inspiral phase and follow the subsequent thermonuclear explosion under the plausible assumption that a detonation forms inmore » the process of merging. We then perform detailed nucleosynthesis calculations and radiative transfer simulations to predict synthetic observables from the homologously expanding supernova ejecta. We find that synthetic color light curves of our merger, which produces about 0.62 M{sub Sun} of {sup 56}Ni, show good agreement with those observed for normal SNe Ia in all wave bands from U to K. Line velocities in synthetic spectra around maximum light also agree well with observations. We conclude that violent mergers of massive white dwarfs can closely resemble normal SNe Ia. Therefore, depending on the number of such massive systems available these mergers may contribute at least a small fraction to the observed population of normal SNe Ia.« less

Reading a Story: Different Degrees of Learning in Different Learning Environments

PubMed Central

Giannini, Anna Maria; Cordellieri, Pierluigi; Piccardi, Laura

2017-01-01

The learning environment in which material is acquired may produce differences in delayed recall and in the elements that individuals focus on. These differences may appear even during development. In the present study, we compared three different learning environments in 450 normally developing 7-year-old children subdivided into three groups according to the type of learning environment. Specifically, children were asked to learn the same material shown in three different learning environments: reading illustrated books (TB); interacting with the same text displayed on a PC monitor and enriched with interactive activities (PC-IA); reading the same text on a PC monitor but not enriched with interactive narratives (PC-NoIA). Our results demonstrated that TB and PC-NoIA elicited better verbal memory recall. In contrast, PC-IA and PC-NoIA produced higher scores for visuo-spatial memory, enhancing memory for spatial relations, positions and colors with respect to TB. Interestingly, only TB seemed to produce a deeper comprehension of the story’s moral. Our results indicated that PC-IA offered a different type of learning that favored visual details. In this sense, interactive activities demonstrate certain limitations, probably due to information overabundance, emotional mobilization, emphasis on images and effort exerted in interactive activities. Thus, interactive activities, although entertaining, act as disruptive elements which interfere with verbal memory and deep moral comprehension. PMID:29085296

[Genetic dissection of intracranial aneurysm].

PubMed

Onda, Hideaki; Yoneyama, Taku; Akagawa, Hiroyuki; Kasuya, Hidetoshi

2008-11-01

Subarachnoid hemorrhage (SAH) due to rupture of an intracranial aneurysm (IA) is a devastating condition with high mortality and morbidity. Genetic as well as environment factors play important roles in the pathogenesis of SAH and IAs. We review the present knowledge on the genetic factors responsible for SAH or IAs. Linkage analysis and association study are used for genetic dissection. Genome-wide linkage analyses have specified several genetic loci for IAs and 6 loci (1p34-36, 7q11, 11q24-25, 14q22-31, 19q13, and Xp22) have been replicated in different populations. Numerous functional and/or positional candidate genes for IAs have been investigated by case-control association studies. The results of genetic association studies are modest because of small sample sizes. To date, no specific genes have been identified as responsible for IA development or rupture. Recent, large-scale genome-wide association (GWA) studies have revealed consistent and replicable genetic markers of several complex diseases such as coronary artery disease and type 2 diabetes. Although, thus far, no GWA studies have been performed for IAs, such a study may accomplish the breakthrough of genetic dissection of IAs. The identification of susceptible genes might lead to the understanding of the mechanism of IA formation or rupture and to novel therapeutic strategies.

An Empirical Fitting Method for Type Ia Supernova Light Curves: A Case Study of SN 2011fe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, WeiKang; Filippenko, Alexei V., E-mail: zwk@astro.berkeley.edu

We present a new empirical fitting method for the optical light curves of Type Ia supernovae (SNe Ia). We find that a variant broken-power-law function provides a good fit, with the simple assumption that the optical emission is approximately the blackbody emission of the expanding fireball. This function is mathematically analytic and is derived directly from the photospheric velocity evolution. When deriving the function, we assume that both the blackbody temperature and photospheric velocity are constant, but the final function is able to accommodate these changes during the fitting procedure. Applying it to the case study of SN 2011fe givesmore » a surprisingly good fit that can describe the light curves from the first-light time to a few weeks after peak brightness, as well as over a large range of fluxes (∼5 mag, and even ∼7 mag in the g band). Since SNe Ia share similar light-curve shapes, this fitting method has the potential to fit most other SNe Ia and characterize their properties in large statistical samples such as those already gathered and in the near future as new facilities become available.« less

Influence of aortic neck characteristics on successful aortic wall penetration of EndoAnchors in therapeutic use during endovascular aneurysm repair.

PubMed

Goudeketting, Seline R; van Noort, Kim; Ouriel, Kenneth; Jordan, William D; Panneton, Jean M; Slump, Cornelis H; de Vries, Jean-Paul P M

2018-04-21

This study sought to quantify EndoAnchor (Medtronic Vascular, Santa Rosa, Calif) penetration into the aortic wall in patients undergoing endovascular abdominal aortic aneurysm repair and to assess predictors of successful penetration and its relationship to postprocedural type IA endoleak. A subset of patients from the Aneurysm Treatment Using the Heli-FX Aortic Securement System Global Registry (ANCHOR) were included if they met the following criteria: the indication for EndoAnchor use was to treat a type IA endoleak, and postprocedure contrast-enhanced computed tomography (CT) scans of sufficient quality were available for core laboratory review. Patients undergoing implantation of cuffs or stents during the EndoAnchor implantation procedure were excluded. Baseline anatomic characteristics were recorded. The cohort was divided into patients with and without persistent type IA endoleaks at the first postoperative CT scan. Penetration of each EndoAnchor measured on this CT scan was defined as good penetration when the EndoAnchor penetrated ≥2 mm into the aortic wall, borderline penetration when EndoAnchor penetration was <2 mm or a gap remained between the endograft and aortic wall, or no penetration when the EndoAnchor did not penetrate into the aortic wall. Differences between the groups were analyzed with the Mann-Whitney U test or Fisher exact test. Multivariate analyses were performed to identify independent predictors of EndoAnchor penetration, and procedural success was defined by absence of type IA endoleak. Eighty-six patients of the primary (n = 61 [71%]) and revision (n = 25 [29%]) arms of the ANCHOR registry were included. There were 53 (62%) without and 33 (38%) with persistent type IA endoleaks on the first postprocedural CT scan. The median number of EndoAnchors with good penetration was significantly greater in the cohort without endoleaks, 4 (interquartile range, 3-5) vs 3 (interquartile range, 1.5-4), respectively (P = .002). A multivariate model for EndoAnchor penetration identified use of a Medtronic Endurant endograft as a factor associated with good penetration (P = .001), whereas poor penetration was associated with a larger aortic neck diameter 10 mm distal to the lowest renal artery (P < .001) and greater proximal neck calcium thickness (P = .004). EndoAnchor penetration was the only variable that attained significance (P < .001) in the multivariate model for successful treatment of a type IA endoleak. Adequate EndoAnchor penetration into the aortic wall is less likely when the aortic neck diameter is large or when the neck contains significant mural calcium. No penetration of the EndoAnchor was the only factor predictive of postprocedural type IA endoleak. This study stresses the importance of careful selection of patients based on preoperative assessment of the infrarenal neck on CT angiography and emphasizes careful deployment of EndoAnchors into the aortic wall to improve successful treatment of type IA endoleaks. Copyright © 2018 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Early Observations of the Type Ia Supernova iPTF 16abc: A Case of Interaction with Nearby, Unbound Material and/or Strong Ejecta Mixing

NASA Astrophysics Data System (ADS)

Miller, A. A.; Cao, Y.; Piro, A. L.; Blagorodnova, N.; Bue, B. D.; Cenko, S. B.; Dhawan, S.; Ferretti, R.; Fox, O. D.; Fremling, C.; Goobar, A.; Howell, D. A.; Hosseinzadeh, G.; Kasliwal, M. M.; Laher, R. R.; Lunnan, R.; Masci, F. J.; McCully, C.; Nugent, P. E.; Sollerman, J.; Taddia, F.; Kulkarni, S. R.

2018-01-01

Early observations of Type Ia supernovae (SNe Ia) provide a unique probe of their progenitor systems and explosion physics. Here we report the intermediate Palomar Transient Factory (iPTF) discovery of an extraordinarily young SN Ia, iPTF 16abc. By fitting a power law to our early light curve, we infer that first light for the SN, that is, when the SN could have first been detected by our survey, occurred only 0.15{+/- }0.070.15 days before our first detection. In the ∼24 hr after discovery, iPTF 16abc rose by ∼2 mag, featuring a near-linear rise in flux for ≳ 3 days. Early spectra show strong C II absorption, which disappears after ∼7 days. Unlike the extensively observed Type Ia SN 2011fe, the {(B-V)}0 colors of iPTF 16abc are blue and nearly constant in the days after explosion. We show that our early observations of iPTF 16abc cannot be explained by either SN shock breakout and the associated, subsequent cooling or the SN ejecta colliding with a stellar companion. Instead, we argue that the early characteristics of iPTF 16abc, including (i) the rapid, near-linear rise, (ii) the nonevolving blue colors, and (iii) the strong C II absorption, are the result of either ejecta interaction with nearby, unbound material or vigorous mixing of radioactive 56Ni in the SN ejecta, or a combination of the two. In the next few years, dozens of very young normal SNe Ia will be discovered, and observations similar to those presented here will constrain the white dwarf explosion mechanism.

Selecting superluminous supernovae in faint galaxies from the first year of the Pan-STARRS1 Medium Deep Survey

NASA Astrophysics Data System (ADS)

McCrum, M.; Smartt, S. J.; Rest, A.; Smith, K.; Kotak, R.; Rodney, S. A.; Young, D. R.; Chornock, R.; Berger, E.; Foley, R. J.; Fraser, M.; Wright, D.; Scolnic, D.; Tonry, J. L.; Urata, Y.; Huang, K.; Pastorello, A.; Botticella, M. T.; Valenti, S.; Mattila, S.; Kankare, E.; Farrow, D. J.; Huber, M. E.; Stubbs, C. W.; Kirshner, R. P.; Bresolin, F.; Burgett, W. S.; Chambers, K. C.; Draper, P. W.; Flewelling, H.; Jedicke, R.; Kaiser, N.; Magnier, E. A.; Metcalfe, N.; Morgan, J. S.; Price, P. A.; Sweeney, W.; Wainscoat, R. J.; Waters, C.

2015-04-01

The Pan-STARRS1 (PS1) survey has obtained imaging in five bands (griz yP1) over 10 Medium Deep Survey (MDS) fields covering a total of 70 square degrees. This paper describes the search for apparently hostless supernovae (SNe) within the first year of PS1 MDS data with an aim of discovering superluminous supernovae (SLSNe). A total of 249 hostless transients were discovered down to a limiting magnitude of MAB ˜ 23.5, of which 76 were classified as Type Ia supernovae (SNe Ia). There were 57 SNe with complete light curves that are likely core-collapse SNe (CCSNe) or type Ic SLSNe and 12 of these have had spectra taken. Of these 12 hostless, non-Type Ia SNe, 7 were SLSNe of type Ic at redshifts between 0.5 and 1.4. This illustrates that the discovery rate of type Ic SLSNe can be maximized by concentrating on hostless transients and removing normal SNe Ia. We present data for two possible SLSNe; PS1-10pm (z = 1.206) and PS1-10ahf (z = 1.1), and estimate the rate of type Ic SLSNe to be between 3^{+3}_{-2}× 10^{-5} and 8^{+2}_{-1}× 10^{-5} that of the CCSN rate within 0.3 ≤ z ≤ 1.4 by applying a Monte Carlo technique. The rate of slowly evolving, type Ic SLSNe (such as SN2007bi) is estimated as a factor of 10 lower than this range.

Associations between Childhood Abuse and Interpersonal Aggression and Suicide Attempt among U.S. Adults in a National Study

PubMed Central

Harford, Thomas C.; Yi, Hsiao-ye; Grant, Bridget F.

2014-01-01

The aim of this study is to examine associations among childhood physical, emotional, or sexual abuse and violence toward self (suicide attempts [SA]) and others (interpersonal aggression [IA]). Data were obtained from the National Epidemiologic Survey on Alcohol and Related Conditions Waves 1 and 2 (n = 34,653). Multinomial logistic regression examined associations between type of childhood abuse and violence categories, adjusting for demographic variables, other childhood adversity, and DSM-IV psychiatric disorders. The prevalence of reported childhood abuse was 4.60% for physical abuse, 7.83% for emotional abuse, and 10.20% for sexual abuse. Approximately 18% of adults reported some form of violent behavior, distributed as follows: IA, 13.37%; SA, 2.64%; and SA with IA, 1.85%. After adjusting for demographic variables, other childhood adversity, and psychiatric disorders, each type of childhood abuse was significantly related to increased risk for each violence category as compared with the no violence category. Furthermore, the odds ratio of childhood physical abuse was significantly higher for SA with IA when compared with IA, and the odds ratio of childhood sexual abuse was significantly higher for SA and SA with IA when compared with IA. Childhood physical, emotional, and sexual abuse is directly related to the risk for violent behaviors to self and others. Both internalizing and externalizing psychiatric disorders impact the association between childhood abuse and violence. The inclusion of suicidal behaviors and interpersonal aggression and internalizing/externalizing psychiatric disorders within an integrated conceptual framework will facilitate more effective interventions for long-lasting effects of child abuse. PMID:24656711

Poor sleep quality and suicide attempt among adults with internet addiction: A nationwide community sample of Korea

PubMed Central

Kim, Kiwon; Lee, Haewoo; Hong, Jin Pyo; Cho, Maeng Je; Fava, Maurizio; Mischoulon, David; Kim, Dong Jun

2017-01-01

Purpose Internet addiction (IA) is defined as a psychological dependence on the internet, regardless of the type of activities once logged on, and previous studies have focused on adolescents and young adults. The aim of this study was to investigate the association between suicide attempts and sleep among community-dwelling adults with IA. Methods The Young’s Internet Addiction Test (IAT), the Korean version of the Composite International Diagnostic Interview (K-CIDI) and a suicide questionnaire were used in this cross-sectional multistage, cluster sampling population-based study. A total of 3212 adults aged 18–64 years were interviewed face-to-face, and they had been randomly selected through a one-person-per-household method. Results Of the 3212 adults, 204 were assessed as having IA (6.35%). Adults with IA were younger, and more frequently male, unmarried, and unemployed, and had poorer sleep quality than adults without IA (32.8% vs. 19.8%), whereas there was no significant difference in the absolute duration of sleep between the two groups. Adults with IA showed more frequent difficulty initiating and maintaining sleep, non-restorative sleep, daytime functional impairment, and duration of sleep more than 10 hours on weekdays than adults without IA. IA with poor sleep quality was significantly associated with lifetime suicide attempts (AOR = 3.34, 95% CI 1.38–8.05) after adjusting for demographic covariates. Adults with IA who had more sleep problems showed more severe IA, especially those who experienced a previous suicidal attempt. Among mental disorders, IA with poor sleep quality was significantly associated with anxiety disorder and overall psychiatric disorders. Conclusions Among adults with IA, poor sleep quality was found to be associated with more severe IA and lifetime suicide attempt. PMID:28384238

Poor sleep quality and suicide attempt among adults with internet addiction: A nationwide community sample of Korea.

PubMed

Kim, Kiwon; Lee, Haewoo; Hong, Jin Pyo; Cho, Maeng Je; Fava, Maurizio; Mischoulon, David; Kim, Dong Jun; Jeon, Hong Jin

2017-01-01

Internet addiction (IA) is defined as a psychological dependence on the internet, regardless of the type of activities once logged on, and previous studies have focused on adolescents and young adults. The aim of this study was to investigate the association between suicide attempts and sleep among community-dwelling adults with IA. The Young's Internet Addiction Test (IAT), the Korean version of the Composite International Diagnostic Interview (K-CIDI) and a suicide questionnaire were used in this cross-sectional multistage, cluster sampling population-based study. A total of 3212 adults aged 18-64 years were interviewed face-to-face, and they had been randomly selected through a one-person-per-household method. Of the 3212 adults, 204 were assessed as having IA (6.35%). Adults with IA were younger, and more frequently male, unmarried, and unemployed, and had poorer sleep quality than adults without IA (32.8% vs. 19.8%), whereas there was no significant difference in the absolute duration of sleep between the two groups. Adults with IA showed more frequent difficulty initiating and maintaining sleep, non-restorative sleep, daytime functional impairment, and duration of sleep more than 10 hours on weekdays than adults without IA. IA with poor sleep quality was significantly associated with lifetime suicide attempts (AOR = 3.34, 95% CI 1.38-8.05) after adjusting for demographic covariates. Adults with IA who had more sleep problems showed more severe IA, especially those who experienced a previous suicidal attempt. Among mental disorders, IA with poor sleep quality was significantly associated with anxiety disorder and overall psychiatric disorders. Among adults with IA, poor sleep quality was found to be associated with more severe IA and lifetime suicide attempt.

Susceptibility of Anthonomus grandis (cotton boll weevil) and Spodoptera frugiperda (fall armyworm) to a cry1ia-type toxin from a Brazilian Bacillus thuringiensis strain.

PubMed

Grossi-de-Sa, Maria Fatima; Quezado de Magalhaes, Mariana; Silva, Marilia Santos; Silva, Shirley Margareth Buffon; Dias, Simoni Campos; Nakasu, Erich Yukio Tempel; Brunetta, Patricia Sanglard Felipe; Oliveira, Gustavo Ramos; Neto, Osmundo Brilhante de Oliveira; Sampaio de Oliveira, Raquel; Soares, Luis Henrique Barros; Ayub, Marco Antonio Zachia; Siqueira, Herbert Alvaro Abreu; Figueira, Edson L Z

2007-09-30

Different isolates of the soil bacterium Bacillus thuringiensis produce multiple crystal (Cry) proteins toxic to a variety of insects, nematodes and protozoans. These insecticidal Cry toxins are known to be active against specific insect orders, being harmless to mammals, birds, amphibians, and reptiles. Due to these characteristics, genes encoding several Cry toxins have been engineered in order to be expressed by a variety of crop plants to control insectpests. The cotton boll weevil, Anthonomus grandis, and the fall armyworm, Spodoptera frugiperda, are the major economically devastating pests of cotton crop in Brazil, causing severe losses, mainly due to their endophytic habit, which results in damages to the cotton boll and floral bud structures. A cry1Ia-type gene, designated cry1Ia12, was isolated and cloned from the Bt S811 strain. Nucleotide sequencing of the cry1Ia12 gene revealed an open reading frame of 2160 bp, encoding a protein of 719 amino acid residues in length, with a predicted molecular mass of 81 kDa. The amino acid sequence of Cry1Ia12 is 99% identical to the known Cry1Ia proteins and differs from them only in one or two amino acid residues positioned along the three domains involved in the insecticidal activity of the toxin. The recombinant Cry1Ia12 protein, corresponding to the cry1Ia12 gene expressed in Escherichia coli cells, showed moderate toxicity towards first instar larvae of both cotton boll weevil and fall armyworm. The highest concentration of the recombinant Cry1Ia12 tested to achieve the maximum toxicities against cotton boll weevil larvae and fall armyworm larvae were 230 microg/mL and 5 microg/mL, respectively. The herein demonstrated insecticidal activity of the recombinant Cry1Ia12 toxin against cotton boll weevil and fall armyworm larvae opens promising perspectives for the genetic engineering of cotton crop resistant to both these devastating pests in Brazil.

The Skin Bacterium Propionibacterium acnes Employs Two Variants of Hyaluronate Lyase with Distinct Properties

PubMed Central

Nazipi, Seven; Stødkilde, Kristian; Scavenius, Carsten

2017-01-01

Hyaluronic acid (HA) and other glycosaminoglycans are extracellular matrix components in the human epidermis and dermis. One of the most prevalent skin microorganisms, Propionibacterium acnes, possesses HA-degrading activity, possibly conferred by the enzyme hyaluronate lyase (HYL). In this study, we identified the HYL of P. acnes and investigated the genotypic and phenotypic characteristics. Investigations include the generation of a P. acnes hyl knockout mutant and HYL activity assays to determine the substrate range and formed products. We found that P. acnes employs two distinct variants of HYL. One variant, HYL-IB/II, is highly active, resulting in complete HA degradation; it is present in strains of the phylotypes IB and II. The other variant, HYL-IA, has low activity, resulting in incomplete HA degradation; it is present in type IA strains. Our findings could explain some of the observed differences between P. acnes phylotype IA and IB/II strains. Whereas type IA strains are primarily found on the skin surface and associated with acne vulgaris, type IB/II strains are more often associated with soft and deep tissue infections, which would require elaborate tissue invasion strategies, possibly accomplished by a highly active HYL-IB/II. PMID:28895889

Diabetes mellitus in a patient with glycogen storage disease type Ia: a case report.

PubMed

Cohn, Aviva; Ohri, Anupam

2017-11-12

Glycogen storage disease type Ia is a genetic disorder that is associated with persistent fasting hypoglycemia and the inability to produce endogenous glucose. The development of diabetes with glycogen storage disease is exceedingly rare. The underlying pathogenesis for developing diabetes in these patients is unclear, and there are no guidelines for treatment. We describe a case of a 34-year-old woman of South Asian descent with glycogen storage disease type Ia, who developed uncontrolled diabetes mellitus as a young adult. Hyperglycemia was noted after childbirth, and worsened years later. Treatment for diabetes was difficult due to risks of hypoglycemia from her underlying glycogen storage disease. With minimal hypoglycemic events, the patient's blood glucose improved with exercise in combination with a sodium-glucose co-transporter 2 inhibitor and an alpha glucosidase inhibitor. We report a rare case of diabetes in the setting of glycogen storage disease-Ia. Based on the literature, there appears to be a relationship between glycogen storage disease and metabolic syndrome, which likely plays a role in the pathogenesis. The management of glycemic control remains a clinical challenge, requiring management of both fasting hypoglycemia from glycogen storage disease, as well as post-prandial hyperglycemia from diabetes mellitus.

iPTF Discoveries of Recent Type Ia Supernovae

NASA Astrophysics Data System (ADS)

Papadogiannakis, S.; Taddia, F.; Petrushevska, T.; Ferretti, R.; Fremling, C.; Karamehmetoglu, E.; Nyholm, A.; Roy, R.; Hangard, L.; Vreeswijk, P.; Horesh, A.; Manulis, I.; Rubin, A.; Yaron, O.; Leloudas, G.; Khazov, D.; Soumagnac, M.; Knezevic, S.; Johansson, J.; Nir, G.; Cao, Y.; Blagorodnova, N.; Kulkarni, S.

2016-05-01

The intermediate Palomar Transient Factory (ATel #4807) reports the discovery and classification of the following Type Ia SNe. Our automated candidate vetting to distinguish a real astrophysical source (1.0) from bogus artefacts (0.0) is powered by three generations of machine learning algorithms: RB2 (Brink et al. 2013MNRAS.435.1047B), RB4 (Rebbapragada et al. 2015AAS...22543402R) and RB5 (Wozniak et al. 2013AAS...22143105W).

iPTF Discoveries of Recent Type Ia Supernova

NASA Astrophysics Data System (ADS)

Petrushevska, T.; Ferretti, R.; Fremling, C.; Hangard, L.; Karamehmetoglu, E.; Nyholm, A.; Papadogiannakis, S.; Roy, R.; Horesh, A.; Khazov, D.; Knezevic, S.; Johansson, J.; Leloudas, G.; Manulis, I.; Rubin, A.; Soumagnac, M.; Vreeswijk, P.; Yaron, O.; Bilgi, P.; Cao, Y.; Duggan, G.; Lunnan, R.; Andreoni, I.

2015-10-01

The intermediate Palomar Transient Factory (ATel #4807) reports the discovery and classification of the following Type Ia SNe. Our automated candidate vetting to distinguish a real astrophysical source (1.0) from bogus artifacts (0.0) is powered by three generations of machine learning algorithms: RB2 (Brink et al. 2013MNRAS.435.1047B), RB4 (Rebbapragada et al. 2015AAS...22543402R) and RB5 (Wozniak et al. 2013AAS...22143105W).

iPTF Discoveries of Recent Type Ia Supernovae

NASA Astrophysics Data System (ADS)

Papadogiannakis, S.; Taddia, F.; Ferretti, R.; Fremling, C.; Karamehmetoglu, E.; Petrushevska, T.; Nyholm, A.; Roy, R.; Hangard, L.; Vreeswijk, P.; Horesh, A.; Manulis, I.; Rubin, A.; Yaron, O.; Leloudas, G.; Khazov, D.; Soumagnac, M.; Knezevic, S.; Johansson, J.; Lunnan, R.; Blagorodnova, N.; Cao, Y.; Cenk, S. B.

2016-01-01

The intermediate Palomar Transient Factory (ATel #4807) reports the discovery and classification of the following Type Ia SNe. Our automated candidate vetting to distinguish a real astrophysical source (1.0) from bogus artifacts (0.0) is powered by three generations of machine learning algorithms: RB2 (Brink et al. 2013MNRAS.435.1047B), RB4 (Rebbapragada et al. 2015AAS...22543402R) and RB5 (Wozniak et al. 2013AAS...22143105W).

iPTF Discoveries of Recent Type Ia Supernovae

NASA Astrophysics Data System (ADS)

Ferretti, R.; Fremling, C.; Hangard, L.; Karamehmetoglu, E.; Nyholm, A.; Papadogiannakis, S.; Petrushevska, T.; Roy, R.; Taddia, F.; Horesh, A.; Khazov, D.; Knezevic, S.; Leloudas, G.; Manulis, I.; Rubin, A.; Soumagnac, M.; Vreeswijk, P.; Yaron, O.; Cao, Y.; Duggan, G.; Lunnan, R.; Blagorodnova, N.

2015-11-01

The intermediate Palomar Transient Factory (ATel #4807) reports the discovery and classification of the following Type Ia SNe. Our automated candidate vetting to distinguish a real astrophysical source (1.0) from bogus artifacts (0.0) is powered by three generations of machine learning algorithms: RB2 (Brink et al. 2013MNRAS.435.1047B), RB4 (Rebbapragada et al. 2015AAS...22543402R) and RB5 (Wozniak et al. 2013AAS...22143105W).

iPTF Discovery of Recent Type Ia Supernovae

NASA Astrophysics Data System (ADS)

Hangard, L.; Ferretti, R.; Fremling, C.; Karamehmetoglu, E.; Nyholm, A.; Papadogiannakis, S.; Petrushevska, T.; Roy, R.; Bar, I.; Horesh, A.; Johansson, J.; Khazov, D.; Knezevic, S.; Leloudas, G.; Manulis, I.; Rubin, A.; Soumagnac, M.; Vreeswijk, P.; Yaron, O.; Cao, Y.; Kulkarni, S.; Lunnan, R.; Ravi, V.; Vedantham, H. K.; Yan, L.

2016-04-01

The intermediate Palomar Transient Factory (ATel #4807) reports the discovery and classification of the following Type Ia SNe. Our automated candidate vetting to distinguish a real astrophysical source (1.0) from bogus artifacts (0.0) is powered by three generations of machine learning algorithms: RB2 (Brink et al. 2013MNRAS.435.1047B), RB4 (Rebbapragada et al. 2015AAS...22543402R) and RB5 (Wozniak et al. 2013AAS...22143105W).

iPTF Discoveries of Recent Type Ia Supernovae

NASA Astrophysics Data System (ADS)

Petrushevska, T.; Ferretti, R.; Fremling, C.; Hangard, L.; Karamehmetoglu, E.; Nyholm, A.; Papadogiannakis, S.; Roy, R.; Horesh, A.; Khazov, D.; Knezevic, S.; Johansson, J.; Leloudas, G.; Manulis, I.; Rubin, A.; Soumagnac, M.; Vreeswijk, P.; Yaron, O.; Bilgi, P.; Cao, Y.; Duggan, G.; Lunnan, R.

2016-02-01

The intermediate Palomar Transient Factory (ATel #4807) reports the discovery and classification of the following Type Ia SNe. Our automated candidate vetting to distinguish a real astrophysical source (1.0) from bogus artifacts (0.0) is powered by three generations of machine learning algorithms: RB2 (Brink et al. 2013MNRAS.435.1047B), RB4 (Rebbapragada et al. 2015AAS...22543402R) and RB5 (Wozniak et al. 2013AAS...22143105W).

iPTF Discovery of Recent Type Ia Supernovae

NASA Astrophysics Data System (ADS)

Hangard, L.; Taddia, F.; Ferretti, R.; Papadogiannakis, S.; Petrushevska, T.; Fremling, C.; Karamehmetoglu, E.; Nyholm, A.; Roy, R.; Horesh, A.; Khazov, D.; Knezevic, S.; Johansson, J.; Leloudas, G.; Manulis, I.; Rubin, A.; Soumagnac, M.; Vreeswijk, P.; Yaron, O.; Bar, I.; Lunnan, R.; Cenk, S. B.

2016-02-01

The intermediate Palomar Transient Factory (ATel #4807) reports the discovery and classification of the following Type Ia SNe. Our automated candidate vetting to distinguish a real astrophysical source (1.0) from bogus artifacts (0.0) is powered by three generations of machine learning algorithms: RB2 (Brink et al. 2013MNRAS.435.1047B), RB4 (Rebbapragada et al. 2015AAS...22543402R) and RB5 (Wozniak et al. 2013AAS...22143105W).

iPTF Discoveries of Recent Type Ia Supernovae

NASA Astrophysics Data System (ADS)

Papadogiannakis, S.; Fremling, C.; Hangard, L.; Karamehmetoglu, E.; Nyholm, A.; Ferretti, R.; Petrushevska, T.; Roy, R.; Taddia, F.; Bar, I.; Horesh, A.; Johansson, J.; Knezevic, S.; Leloudas, G.; Manulis, I.; Nir, G.; Rubin, A.; Soumagnac, M.; Vreeswijk, P.; Yaron, O.; Arcavi, I.; Howell, D. A.; McCully, C.; Hosseinzadeh, G.; Valenti, S.; Blagorodnova, N.; Cao, Y.; Duggan, G.; Ravi, V.; Lunnan, R.

2016-03-01

The intermediate Palomar Transient Factory (ATel #4807) reports the discovery and classification of the following Type Ia SNe. Our automated candidate vetting to distinguish a real astrophysical source (1.0) from bogus artifacts (0.0) is powered by three generations of machine learning algorithms: RB2 (Brink et al. 2013MNRAS.435.1047B), RB4 (Rebbapragada et al. 2015AAS...22543402R) and RB5 (Wozniak et al. 2013AAS...22143105W).

iPTF discoveries of recent type Ia supernovae

NASA Astrophysics Data System (ADS)

Papadogiannakis, S.; Ferretti, R.; Fremling, C.; Hangard, L.; Karamehmetoglu, E.; Nyholm, A.; Petrushevska, T.; Roy, R.; De Cia, A.; Vreeswijk, P.; Horesh, A.; Manulis, I.; Sagiv, I.; Rubin, A.; Yaron, O.; Leloudas, G.; Khazov, D.; Soumagnac, M.; Knezevic, S.; Cenko, S. B.; Capone, J.; Bartakk, M.

2015-09-01

The intermediate Palomar Transient Factory (ATel #4807) reports the discovery and classification of the following Type Ia SNe. Our automated candidate vetting to distinguish a real astrophysical source (1.0) from bogus artifacts (0.0) is powered by three generations of machine learning algorithms: RB2 (Brink et al. 2013MNRAS.435.1047B), RB4 (Rebbapragada et al. 2015AAS...22543402R) and RB5 (Wozniak et al. 2013AAS...22143105W).

iPTF Discovery of Recent Type Ia Supernova

NASA Astrophysics Data System (ADS)

Hangard, L.; Petrushevska, T.; Papadogiannakis, S.; Ferretti, R.; Fremling, C.; Karamehmetoglu, E.; Nyholm, A.; Roy, R.; Horesh, A.; Khazov, D.; Knezevic, S.; Johansson, J.; Leloudas, G.; Manulis, I.; Rubin, A.; Soumagnac, M.; Vreeswijk, P.; Yaron, O.; Kasliwal, M.

2015-10-01

The intermediate Palomar Transient Factory (ATel #4807) reports the discovery and classification of the following Type Ia SNe. Our automated candidate vetting to distinguish a real astrophysical source (1.0) from bogus artifacts (0.0) is powered by three generations of machine learning algorithms: RB2 (Brink et al. 2013MNRAS.435.1047B), RB4 (Rebbapragada et al. 2015AAS...22543402R) and RB5 (Wozniak et al. 2013AAS...22143105W).

iPTF Discoveries of Recent Type Ia Supernovae

NASA Astrophysics Data System (ADS)

Petrushevska, T.; Ferretti, R.; Fremling, C.; Hangard, L.; Karamehmetoglu, E.; Nyholm, A.; Papadogiannakis, S.; Roy, R.; Horesh, A.; Khazov, D.; Knezevic, S.; Johansson, J.; Leloudas, G.; Manulis, I.; Rubin, A.; Soumagnac, M.; Vreeswijk, P.; Yaron, O.; Bilgi, P.; Cao, Y.; Duggan, G.; Lunnan, R.; Neill, J. D.; Walters, R.

2016-04-01

The intermediate Palomar Transient Factory (ATel #4807) reports the discovery and classification of the following Type Ia SNe. Our automated candidate vetting to distinguish a real astrophysical source (1.0) from bogus artifacts (0.0) is powered by three generations of machine learning algorithms: RB2 (Brink et al. 2013MNRAS.435.1047B), RB4 (Rebbapragada et al. 2015AAS...22543402R) and RB5 (Wozniak et al. 2013AAS...22143105W).

iPTF Discoveries of Recent Type Ia Supernovae

NASA Astrophysics Data System (ADS)

Papadogiannakis, S.; Taddia, F.; Petrushevska, T.; Fremling, C.; Hangard, L.; Johansson, J.; Karamehmetoglu, E.; Migotto, K.; Nyholm, A.; Roy, R.; Ben-Ami, S.; De Cia, A.; Dzigan, Y.; Horesh, A.; Khazov, D.; Soumagnac, M.; Manulis, I.; Rubin, A.; Sagiv, I.; Vreeswijk, P.; Yaron, O.; Bond, H.; Bilgi, P.; Cao, Y.; Duggan, G.

2015-03-01

The intermediate Palomar Transient Factory (ATel #4807) reports the discovery and classification of the following Type Ia SNe. Our automated candidate vetting to distinguish a real astrophysical source (1.0) from bogus artifacts (0.0) is powered by three generations of machine learning algorithms: RB2 (Brink et al. 2013MNRAS.435.1047B), RB4 (Rebbapragada et al. 2015AAS...22543402R) and RB5 (Wozniak et al. 2013AAS...22143105W).

iPTF Discovery of Recent Type Ia Supernovae

NASA Astrophysics Data System (ADS)

Hangard, L.; Ferretti, R.; Papadogiannakis, S.; Petrushevska, T.; Fremling, C.; Karamehmetoglu, E.; Nyholm, A.; Roy, R.; Horesh, A.; Khazov, D.; Knezevic, S.; Johansson, J.; Leloudas, G.; Manulis, I.; Rubin, A.; Soumagnac, M.; Vreeswijk, P.; Yaron, O.; Cook, D.

2015-12-01

The intermediate Palomar Transient Factory (ATel #4807) reports the discovery and classification of the following Type Ia SNe. Our automated candidate vetting to distinguish a real astrophysical source (1.0) from bogus artifacts (0.0) is powered by three generations of machine learning algorithms: RB2 (Brink et al. 2013MNRAS.435.1047B), RB4 (Rebbapragada et al. 2015AAS...22543402R) and RB5 (Wozniak et al. 2013AAS...22143105W).

iPTF Discoveries of Recent Type Ia Supernova

NASA Astrophysics Data System (ADS)

Petrushevska, T.; Ferretti, R.; Fremling, C.; Hangard, L.; Karamehmetoglu, E.; Nyholm, A.; Papadogiannakis, S.; Roy, R.; Horesh, A.; Khazov, D.; Knezevic, S.; Johansson, J.; Leloudas, G.; Manulis, I.; Rubin, A.; Soumagnac, M.; Vreeswijk, P.; Yaron, O.; Bilgi, P.; Cao, Y.; Duggan, G.; Lunnan, R.; Jencson, J.

2015-11-01

The intermediate Palomar Transient Factory (ATel #4807) reports the discovery and classification of the following Type Ia SNe. Our automated candidate vetting to distinguish a real astrophysical source (1.0) from bogus artifacts (0.0) is powered by three generations of machine learning algorithms: RB2 (Brink et al. 2013MNRAS.435.1047B), RB4 (Rebbapragada et al. 2015AAS...22543402R) and RB5 (Wozniak et al. 2013AAS...22143105W).

Radio constraints on the mass-loss rate of the Type Ia SN 2018gv

NASA Astrophysics Data System (ADS)

Ryder, S. D.; Lundqvist, P.; Perez-Torres, M. A.; Kundu, E.; Kool, E. C.; Bjornsson, C.-I.; Fransson, C.

2018-01-01

The young Type Ia SN 2018gv (ATel #11175, #11177) in the galaxy NGC 2525 has been observed with the Australia Telescope Compact Array (ATCA) at 5.5 and 9.0 GHz on 2018 Jan 18.6 UT. No radio emission was detected at the reported location, to a 3-sigma upper limit of 120 microJy/beam (5.5 GHz) and 30 microJy/beam (9.0 GHz).

Spectroscopic Classification of SN 2018nt as a Reddened Type Ia Supernova

NASA Astrophysics Data System (ADS)

Vinko, J.; Szeged, U.; Wheeler, J. C.

2018-02-01

An optical spectrum (range 360-700 nm) of SN 2018nt (K2 C16-0043), was obtained with the "Low Resolution Spectrograph-2" (LRS2) on the 10m Hobby-Eberly Telescope at McDonald Observatory by S. Odewahn on 2018 Feb 05.20 UT. The spectrum is consistent with that of a heavily reddened Type Ia supernova (with Av > 2 mag) about 3 weeks after maximum light.

Spectroscopic classification of AT 2017cfd as a young Type Ia supernova

NASA Astrophysics Data System (ADS)

Vinko, J.; Wheeler, J. C.

2017-03-01

We report the spectroscopic observation of AT 2017cfd, a transient discovered by the Lick Observatory Supernova Search (LOSS) on 2017-03-16. A spectrum (range 3700-9300 Angstroms), taken with the new "Low Resolution Spectrograph-2" (LRS2) on the 10m Hobby-Eberly Telescope at McDonald Observatory by Steve Odewahn on 2017-03-18.16 UT, is similar to that of a Type Ia supernova before maximum light.

Imaging the atomic structure and local chemistry of platelets in natural type Ia diamond

NASA Astrophysics Data System (ADS)

Olivier, E. J.; Neethling, J. H.; Kroon, R. E.; Naidoo, S. R.; Allen, C. S.; Sawada, H.; van Aken, P. A.; Kirkland, A. I.

2018-03-01

In the past decades, many efforts have been devoted to characterizing {001} platelet defects in type Ia diamond. It is known that N is concentrated at the defect core. However, an accurate description of the atomic structure of the defect and the role that N plays in it is still unknown. Here, by using aberration-corrected transmission electron microscopy and electron energy-loss spectroscopy we have determined the atomic arrangement within platelet defects in a natural type Ia diamond and matched it to a prevalent theoretical model. The platelet has an anisotropic atomic structure with a zigzag ordering of defect pairs along the defect line. The electron energy-loss near-edge fine structure of both carbon K- and nitrogen K-edges obtained from the platelet core is consistent with a trigonal bonding arrangement at interstitial sites. The experimental observations support an interstitial aggregate mode of formation for platelet defects in natural diamond.

Imaging the atomic structure and local chemistry of platelets in natural type Ia diamond.

PubMed

Olivier, E J; Neethling, J H; Kroon, R E; Naidoo, S R; Allen, C S; Sawada, H; van Aken, P A; Kirkland, A I

2018-03-01

In the past decades, many efforts have been devoted to characterizing {001} platelet defects in type Ia diamond. It is known that N is concentrated at the defect core. However, an accurate description of the atomic structure of the defect and the role that N plays in it is still unknown. Here, by using aberration-corrected transmission electron microscopy and electron energy-loss spectroscopy we have determined the atomic arrangement within platelet defects in a natural type Ia diamond and matched it to a prevalent theoretical model. The platelet has an anisotropic atomic structure with a zigzag ordering of defect pairs along the defect line. The electron energy-loss near-edge fine structure of both carbon K- and nitrogen K-edges obtained from the platelet core is consistent with a trigonal bonding arrangement at interstitial sites. The experimental observations support an interstitial aggregate mode of formation for platelet defects in natural diamond.

The Type Ia Supernova Rate and Delay-Time Distribution

NASA Astrophysics Data System (ADS)

Graur, Or

2013-11-01

The nature of the progenitor stellar systems of thermonuclear, or Type Ia, supernovae (SNe Ia) remains unknown. Unlike core-collapse (CC) SNe, which have been successfully linked, at least partially, to various types of massive stars, the progenitors of SNe Ia are to date undetected in pre-explosion images and the nature of these progenitors can only be probed using indirect methods. In this thesis, I present three SN surveys aimed at measuring the rates at which SNe Ia explode at different times throughout the Universe's history and in different types of galaxies. I use these rates to re-construct the SN Ia delay-time distribution (DTD), a function that connects between the star-formation history (SFH) of a specific stellar environment and its SN Ia rate, and I use it to constrain different progenitor models. In Chapter 1, I provide a brief introduction of the field. This is followed, in Chapter 2, by a description of the Subaru Deep Field (SDF) SN Survey. Over a period of three years between 2005-2008, the SDF was observed on four independent epochs with Suprime-Cam on the Subaru 8.2-m telescope, with two nights of exposure per epoch, in the R, i', and z' bands. In this survey, I discover 150 SNe out to redshift z ~ 2, including 27 SNe Ia in the range 1.0 < z < 1.5 and 10 in the range 1.5 < z < 2.0. The SN Ia rate measurements from this sample are consistent with those derived from the Hubble Space Telescope (HST) GOODS sample, but the overall uncertainty of the 1.5 < z < 2.0 measurement is a factor of 2 smaller, of 35-50%. Based on this sample, we find that the SN Ia rate evolution levels off at 1.0 < z < 2.0, but shows no sign of declining. Combining our SN Ia rate measurements and those from the literature, and comparing to a wide range of possible SFHs, the best-fitting DTD is a power law of the form Psi(t) ~ t^beta, with index beta = -1.1 ± 0.1 (statistical) ± 0.17 (systematic). By combining the contribution from CC SNe, based on the wide range of SFHs, with that from SNe Ia, calculated with the best-fitting DTD, we map the cosmic history of iron accumulation and predict that the mean present-day cosmic iron abundance is in the range Z_Fe = (0.09-0.37) Z_Fe,solar. Most SNe have been discovered in dedicated imaging surveys and have been classified by means of follow-up spectroscopy. However, it is also possible to combine the discovery and classification stages by means of a spectroscopic SN survey. In Chapter 3, I develop a method to detect SN spectra buried in galaxy spectra acquired by large-scale spectroscopic galaxy surveys. Applying this procedure to the ~700,000 galaxy spectra in the 7th Data Release of the Sloan Digital Sky Survey (SDSS) that have SFHs derived with the VErsatile SPectral Analysis code (VESPA), I detect 90 SNe Ia and 10 Type II SNe. I use the SN Ia sample to measure SN Ia rates per unit stellar mass and confirm, at the median redshift of the sample, z = 0.1, the inverse dependence on galaxy mass of the SN Ia rate per unit mass, previously reported by Li et al. (2011a) for a local sample. I further confirm, following Kistler et al. (2013), that this relation can be explained by the combination of galaxy "downsizing" and a power-law DTD with an index of -1. Finally, I use the SN sample, combined with the individual galaxy SFHs, to derive the late component of the DTD, finding a value consistent with previous derivations. Chapter 4 presents the near-final SN sample and SN Ia rates from the Cluster Lensing And Supernova survey with Hubble (CLASH). Using the Advanced Camera for Surveys and the Wide Field Camera 3 on HST, we image 25 galaxy clusters and blank fields of galaxies. I report a sample of 22 SNe discovered in the blank fields around 20 of the 25 galaxy clusters. Of these, 11 are classified as SNe Ia, including four SNe Ia at redshifts z > 1.2. I measure volumetric SN Ia rates out to redshift z = 1.8 and add the first upper limit on the SN Ia rate in the range 1.8 < z < 2.4. The results are consistent with the rates I measure in Chapter 2 and with those from the HST/GOODS survey. Together with the most accurate and precise measurements at redshifts z < 1, they result in a best-fitting power-law DTD with an index of -0.93 +0.05(0.11) -0.06(0.12) (statistical) +0.12 -0.08 (systematic). The results of Chapters 2-4, summarized in Chapter 5, join other recent evidence suggestive of the double-degenerate progenitor scenario. A power-law DTD with an index of ~-1 can be explained by the gravitational merger of two carbon-oxygen white dwarfs. However, this form of the DTD does not necessarily exclude other progenitor scenarios or the possibility that there is more than one SN Ia production channel. In Chapter 5, I describe ongoing and future work that addresses this problem. Specifically, it may be possible to infer the existence of multiple production channels by studying the prompt component of the DTD. This can be achieved either by measuring volumetric SN Ia rates at higher redshifts than presented here, or by measuring SN Ia rates per unit mass in low-mass, dwarf galaxies. I present an initial sample of four SNe Ia discovered among ~52,000 SDSS galaxy spectra using the procedure developed in Chapter 3. The rate measured with this sample is not accurate enough to distinguish between DTD models, but it shows that with a larger galaxy sample, such as is being acquired by future iterations of the SDSS, such distinction will be possible. Finally, I show in Chapter 5 initial results from a program to obtain spectroscopic redshifts for the SN host galaxies in Chapter 2 with the highest photometric-based redshifts. This will eventually reduce the systematic error in the high-redshift SN Ia rate.

Variability and mass loss in IA O-B-A supergiants

NASA Technical Reports Server (NTRS)

Schild, R. E.; Garrison, R. F.; Hiltner, W. A.

1983-01-01

Recently completed catalogs of MK spectral types and UBV photometry of 1227 OB stars in the southern Milky Way have been analyzed to investigate brightness and color variability among the Ia supergiants. It is found that brightness variability is common among the O9-B1 supergiants with typical amplitudes about 0.1 and time scales longer than a week and shorter than 1000 days. Among the A supergiants fluctuations in U-B color are found on similar time scales and with amplitude about 0.1. For many early Ia supergiants there is a poor correlation between Balmer jump and spectral type, as had been known previously. An attempt to correlate the Balmer jump deficiency with mass loss rate yielded uncertain results.

Anomalous ionization seen in the spectra of B supergiants

NASA Technical Reports Server (NTRS)

Cassinelli, J. P.; Abbott, D. C.

1981-01-01

An IUE survey of B supergiants has been conducted to study the persistence with spectral type of the ultraviolet resonance lines of N V, C IV and Si IV. N V is seen as late as B2.5Ia, C IV until B6Ia and Si IV throughout the range from B1.5 to B9. This is in fairly good agreement with the Auger ionization model of Cassinelli and Olson (1979). The terminal velocities are derived for the 20 stars in the sample and it is found that the ratio v(T)/v(esc) decreases monotonically with spectral type from the value of 3.0 that it has in the O spectral range to the value 1.0 at B9Ia.

Nucleosynthesis by Type Ia Supernova for different Metallicity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ohkubo, Takuya; Umeda, Hideyuki; Nomoto, Ken'ichi

2006-07-12

We calculate nucleosynthesis by type Ia supernova for various metallicity. We adopt two typical hydrodynamical models, carbon deflagration and delayed detonation. The two main points of this research are to see that (1)how the ejected mass of 56Ni changes and (2)how abundance of each element (especially Fe-group elements) is influenced by varying metallicity. We find that (1)56Ni mass changes about 15% in the range of Z = 0.001 - 0.05 and insufficient to explain all of the observed variety of SNe Ia peak luminosity, and (2)[Mn/Fe] and [Ni/Fe] show fairy dependence on metallicity (especially for delayed detonation model) while [Cr/Fe]more » or [{alpha}/Fe] do not.« less

A distance-independent calibration of the luminosity of type Ia supernovae and the Hubble constant

NASA Technical Reports Server (NTRS)

Leibundgut, Bruno; Pinto, Philip A.

1992-01-01

The absolute magnitude of SNe Ia at maximum is calibrated here using radioactive decay models for the light curve and a minimum of assumptions. The absolute magnitude parameter space is studied using explosion models and a range of rise times, and absolute B magnitudes at maximum are used to derive a range of the H0 and the distance to the Virgo Cluster from SNe Ia. Rigorous limits for H0 of 45 and 105 km/s/Mpc are derived.

Spectral Classification of MASTER J221505.32+101812.6

NASA Astrophysics Data System (ADS)

Silverman, J. M.; Cohen, D. P.; Filippenko, A. V.

2012-06-01

We report that inspection of a CCD spectrum (range 340-1000 nm), obtained on June 27.4 UT with the Shane 3-m reflector (+ Kast spectrograph) at Lick Observatory, shows that MASTER J221505.32+101812.6 (ATel #4213) is a Type Ia supernova (SN Ia). Cross-correlation with a library of SN spectra using the "SuperNova IDentification" code (SNID; Blondin & Tonry 2007, Ap.J. 666, 1024) indicates that the object is a normal SN Ia near maximum brightness at a redshift of 0.090.

Caught in the Act: UV spectroscopy of the ejecta-companion collision from a type Ia supernova

NASA Astrophysics Data System (ADS)

Kulkarni, Shrinivas

2017-08-01

There is now significant observational evidence for both of the leading models proposed to explain the origin of type Ia supernovae (SNe). While the majority of SNe Ia likely come from the merger of two white dwarf (WD) stars (known as the double degenerate model), a significant fraction are the result of a WD accreting mass from the hydrogen envelope of a binary companion (known as the single degenerate model). Eventually, as the accreting WD approaches the Chandrasekhar limit, the onset of unstable burning occurs ultimately leading to a thermonuclear explosion. With observational evidence for both channels firmly in place, future efforts to better understand the progenitors of SNe Ia will require detailed studies of individual systems.A fundamental expectation of the single degenerate model is that the collision of the blast wave with the donor star will produce a unique signature - a bright and rapidly declining UV pulse. This UV signal has only been previously observed in a single SN. Here, we propose to undertake STIS UV spectroscopy of one infant type Ia SN with similarly strong UV emission. The spectra will provide unique and detailed insight into the ejecta-companion interaction while also probing the chemical abundance of the outermost layers of the SN ejecta. The ejecta-companion signature is only visible UV, and HST/STIS is the only instrument capable of obtaining the spectra that are needed as a detailed probe of the interaction physics.

Association of intracranial aneurysm rupture with smoking duration, intensity, and cessation.

PubMed

Can, Anil; Castro, Victor M; Ozdemir, Yildirim H; Dagen, Sarajune; Yu, Sheng; Dligach, Dmitriy; Finan, Sean; Gainer, Vivian; Shadick, Nancy A; Murphy, Shawn; Cai, Tianxi; Savova, Guergana; Dammers, Ruben; Weiss, Scott T; Du, Rose

2017-09-26

Although smoking is a known risk factor for intracranial aneurysm (IA) rupture, the exact relationship between IA rupture and smoking intensity and duration, as well as duration of smoking cessation, remains unknown. In this case-control study, we analyzed 4,701 patients with 6,411 IAs diagnosed at the Brigham and Women's Hospital and Massachusetts General Hospital between 1990 and 2016. We divided individuals into patients with ruptured aneurysms and controls with unruptured aneurysms. We performed univariable and multivariable logistic regression analyses to determine the association between smoking status and ruptured IAs at presentation. In a subgroup analysis among former and current smokers, we assessed the association between ruptured aneurysms and number of packs per day, duration of smoking, and duration since smoking cessation. In multivariable analysis, current (odds ratio [OR] 2.21, 95% confidence interval [CI] 1.89-2.59) and former smoking status (OR 1.56, 95% CI 1.31-1.86) were associated with rupture status at presentation compared with never smokers. In a subgroup analysis among current and former smokers, years smoked (OR 1.02, 95% CI 1.01-1.03) and packs per day (OR 1.46, 95% CI 1.25-1.70) were significantly associated with ruptured aneurysms at presentation, whereas duration since cessation among former smokers was not significant (OR 1.00, 95% CI 0.99-1.02). Current cigarette smoking, smoking intensity, and smoking duration are significantly associated with ruptured IAs at presentation. However, the significantly increased risk persists after smoking cessation, and smoking cessation does not confer a reduced risk of aneurysmal subarachnoid hemorrhage beyond that of reducing the cumulative dose. © 2017 American Academy of Neurology.

Photometric classification of type Ia supernovae in the SuperNova Legacy Survey with supervised learning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Möller, A.; Ruhlmann-Kleider, V.; Leloup, C.

In the era of large astronomical surveys, photometric classification of supernovae (SNe) has become an important research field due to limited spectroscopic resources for candidate follow-up and classification. In this work, we present a method to photometrically classify type Ia supernovae based on machine learning with redshifts that are derived from the SN light-curves. This method is implemented on real data from the SNLS deferred pipeline, a purely photometric pipeline that identifies SNe Ia at high-redshifts (0.2 < z < 1.1). Our method consists of two stages: feature extraction (obtaining the SN redshift from photometry and estimating light-curve shape parameters)more » and machine learning classification. We study the performance of different algorithms such as Random Forest and Boosted Decision Trees. We evaluate the performance using SN simulations and real data from the first 3 years of the Supernova Legacy Survey (SNLS), which contains large spectroscopically and photometrically classified type Ia samples. Using the Area Under the Curve (AUC) metric, where perfect classification is given by 1, we find that our best-performing classifier (Extreme Gradient Boosting Decision Tree) has an AUC of 0.98.We show that it is possible to obtain a large photometrically selected type Ia SN sample with an estimated contamination of less than 5%. When applied to data from the first three years of SNLS, we obtain 529 events. We investigate the differences between classifying simulated SNe, and real SN survey data. In particular, we find that applying a thorough set of selection cuts to the SN sample is essential for good classification. This work demonstrates for the first time the feasibility of machine learning classification in a high- z SN survey with application to real SN data.« less

Investigating the impact of a health game on implicit attitudes towards food and food choice behaviour of young adults.

PubMed

Alblas, Eva; Folkvord, Frans; Anschütz, Doeschka J; van 't Riet, Jonathan; Granic, Isabela; Ketelaar, Paul; Buijzen, Moniek

2018-05-25

Improving diets by stimulating fruit and vegetable consumption might be beneficial, in particular when they substitute energy-dense products. The aim of present study was to investigate whether a health game can be used to positively affect healthy implicit attitudes (IAs) towards food and subsequent food choice behaviour of young adults. A 2 (Time: baseline vs. post-test) x 2 (Condition: health game vs. control game) x 2 (Baseline IAs: healthy IAs vs. less healthy IAs) mixed-subjects design was used with 125 participants (age: M = 20.17, SD = 1.88). IAs towards food were assessed at baseline and post-test using an Implicit Association Test (IAT). Additionally, food choice behaviour was assessed after game play. At baseline, the majority of participants had healthy IAs (i.e., favouring fruit over chocolate snacks). At post-test, significantly less healthy IAs were observed in the control condition, while this reduction was not significant in the health game condition. Regarding food choice behaviour, participants with healthy baseline IAs were more likely to select fruit in the health game condition than participants with healthy baseline IAs in the control game condition. However, participants with less healthy baseline IAs were less likely to select fruit in the health game condition than in the control condition. We found tentative support that health games can be used to influence IAs towards food and positively affect food choice behaviour. However, this influence was only observed for those with healthy baseline IAs. The current version of the health game would primarily benefit those already healthy and could negatively affect those that need the intervention most, so modifications are recommendable. Copyright © 2018. Published by Elsevier Ltd.

Estimating dust distances to Type Ia supernovae from colour excess time evolution

NASA Astrophysics Data System (ADS)

Bulla, M.; Goobar, A.; Amanullah, R.; Feindt, U.; Ferretti, R.

2018-01-01

We present a new technique to infer dust locations towards reddened Type Ia supernovae and to help discriminate between an interstellar and a circumstellar origin for the observed extinction. Using Monte Carlo simulations, we show that the time evolution of the light-curve shape and especially of the colour excess E(B - V) places strong constraints on the distance between dust and the supernova. We apply our approach to two highly reddened Type Ia supernovae for which dust distance estimates are available in the literature: SN 2006X and SN 2014J. For the former, we obtain a time-variable E(B - V) and from this derive a distance of 27.5^{+9.0}_{-4.9} or 22.1^{+6.0}_{-3.8} pc depending on whether dust properties typical of the Large Magellanic Cloud (LMC) or the Milky Way (MW) are used. For the latter, instead, we obtain a constant E(B - V) consistent with dust at distances larger than ∼50 and 38 pc for LMC- and MW-type dust, respectively. Values thus extracted are in excellent agreement with previous estimates for the two supernovae. Our findings suggest that dust responsible for the extinction towards these supernovae is likely to be located within interstellar clouds. We also discuss how other properties of reddened Type Ia supernovae - such as their peculiar extinction and polarization behaviour and the detection of variable, blue-shifted sodium features in some of these events - might be compatible with dust and gas at interstellar-scale distances.

Type Ia Supernovae: Nature's Grandest Thermonuclear Explosions

NASA Astrophysics Data System (ADS)

Woosley, Stan

2003-10-01

When carbon fusion ignites near the center of an accreting white dwarf near the Chandrasekhar Mass, an irreversible series of events is initiated that ultimately leads to the complete disruption of the star and a bright display powered by radioactive decay. Though studied for over 40 years, the details of how this happens remain elusive. Three areas of uncertainty will be discussed: 1) the "ignition" of the bomb: one point or many, central or off-center; 2) the propagation of an unconfined Rayleigh-Taylor unstable burning front - does a robust transition to detonation occur as the front moves into a regime of ``distributed burning"? 3) the generation of the light curve and the Philipps relation. Studies of question 1), equally critical to the other two, suggest a dipolar flow at ignition time and off-center ignition. There may be an uncontrolable degree of chaos in the peak brightness resulting from the ignition process that will affect how SN Ia are used for cosmology. Question 2) is a frontier subject in the chemical combustion community. Results of new multi-dimensional studies will be presented. Question 3) involves atomic physics more than hydrodynamics, but current views suggest that SN Ia light curves should be characterized, at some level, by more than a single parameter.

Phylogeny of the Viral Hemorrhagic Septicemia Virus in European Aquaculture

PubMed Central

Cieslak, Michael; Mikkelsen, Susie S.; Skall, Helle F.; Baud, Marine; Diserens, Nicolas; Engelsma, Marc Y.; Haenen, Olga L. M.; Mousakhani, Shirin; Panzarin, Valentina; Wahli, Thomas; Olesen, Niels J.; Schütze, Heike

2016-01-01

One of the most valuable aquaculture fish in Europe is the rainbow trout, Oncorhynchus mykiss, but the profitability of trout production is threatened by a highly lethal infectious disease, viral hemorrhagic septicemia (VHS), caused by the VHS virus (VHSV). For the past few decades, the subgenogroup Ia of VHSV has been the main cause of VHS outbreaks in European freshwater-farmed rainbow trout. Little is currently known, however, about the phylogenetic radiation of this Ia lineage into subordinate Ia clades and their subsequent geographical spread routes. We investigated this topic using the largest Ia-isolate dataset ever compiled, comprising 651 complete G gene sequences: 209 GenBank Ia isolates and 442 Ia isolates from this study. The sequences come from 11 European countries and cover the period 1971–2015. Based on this dataset, we documented the extensive spread of the Ia population and the strong mixing of Ia isolates, assumed to be the result of the Europe-wide trout trade. For example, the Ia lineage underwent a radiation into nine Ia clades, most of which are difficult to allocate to a specific geographic distribution. Furthermore, we found indications for two rapid, large-scale population growth events, and identified three polytomies among the Ia clades, both of which possibly indicate a rapid radiation. However, only about 4% of Ia haplotypes (out of 398) occur in more than one European country. This apparently conflicting finding regarding the Europe-wide spread and mixing of Ia isolates can be explained by the high mutation rate of VHSV. Accordingly, the mean period of occurrence of a single Ia haplotype was less than a full year, and we found a substitution rate of up to 7.813 × 10−4 nucleotides per site per year. Finally, we documented significant differences between Germany and Denmark regarding their VHS epidemiology, apparently due to those countries’ individual handling of VHS. PMID:27760205

SCALA: In situ calibration for integral field spectrographs

NASA Astrophysics Data System (ADS)

Lombardo, S.; Küsters, D.; Kowalski, M.; Aldering, G.; Antilogus, P.; Bailey, S.; Baltay, C.; Barbary, K.; Baugh, D.; Bongard, S.; Boone, K.; Buton, C.; Chen, J.; Chotard, N.; Copin, Y.; Dixon, S.; Fagrelius, P.; Feindt, U.; Fouchez, D.; Gangler, E.; Hayden, B.; Hillebrandt, W.; Hoffmann, A.; Kim, A. G.; Leget, P.-F.; McKay, L.; Nordin, J.; Pain, R.; Pécontal, E.; Pereira, R.; Perlmutter, S.; Rabinowitz, D.; Reif, K.; Rigault, M.; Rubin, D.; Runge, K.; Saunders, C.; Smadja, G.; Suzuki, N.; Taubenberger, S.; Tao, C.; Thomas, R. C.; Nearby Supernova Factory

2017-11-01

Aims: The scientific yield of current and future optical surveys is increasingly limited by systematic uncertainties in the flux calibration. This is the case for type Ia supernova (SN Ia) cosmology programs, where an improved calibration directly translates into improved cosmological constraints. Current methodology rests on models of stars. Here we aim to obtain flux calibration that is traceable to state-of-the-art detector-based calibration. Methods: We present the SNIFS Calibration Apparatus (SCALA), a color (relative) flux calibration system developed for the SuperNova integral field spectrograph (SNIFS), operating at the University of Hawaii 2.2 m (UH 88) telescope. Results: By comparing the color trend of the illumination generated by SCALA during two commissioning runs, and to previous laboratory measurements, we show that we can determine the light emitted by SCALA with a long-term repeatability better than 1%. We describe the calibration procedure necessary to control for system aging. We present measurements of the SNIFS throughput as estimated by SCALA observations. Conclusions: The SCALA calibration unit is now fully deployed at the UH 88 telescope, and with it color-calibration between 4000 Å and 9000 Å is stable at the percent level over a one-year baseline.

Subdiaphragmatic vagotomy increases the sensitivity of lumbar Aδ primary afferent neurons along with voltage-dependent potassium channels in rats.

PubMed

Furuta, Sadayoshi; Watanabe, Lisa; Doi, Seira; Horiuchi, Hiroshi; Matsumoto, Kenjiro; Kuzumaki, Naoko; Suzuki, Tsutomu; Narita, Minoru

2012-02-01

Subdiaphragmatic vagal dysfunction causes chronic pain. To verify whether this chronic pain is accompanied by enhanced peripheral nociceptive sensitivity, we evaluated primary afferent neuronal excitability in subdiaphragmatic vagotomized (SDV) rats. SDV rats showed a decrease in the electrical stimuli-induced hind limb-flexion threshold at 250 Hz, but showed no similar effect at 5 or 2000 Hz, which indicated that lumbar primary afferent Aδ sensitivity was enhanced in SDV rats. The whole-cell patch-clamp technique also revealed the hyper-excitability of acutely dissociated medium-sized lumbar dorsal root ganglion (DRG) neurons isolated from SDV rats. The contribution of changes in voltage-dependent potassium (Kv) channels was assessed, and transient A-type K(+) (I(A) ) current density was apparently decreased. Moreover, Kv4.3 immunoreactivity in medium-sized DRG neurons was significantly reduced in SDV rats compared to sham. These results indicate that SDV causes hyper-excitability of lumbar primary Aδ afferent neurons, which may be induced along with suppressing I(A) currents via the decreased expression of Kv4.3. Thus, peripheral Aδ neuroplasticity may contribute to the chronic lower limb pain caused by SDV. Copyright © 2011 Wiley Periodicals, Inc.

Spectroscopic classification of AT 2017byx as a Type Ia Supernova

NASA Astrophysics Data System (ADS)

Vinko, J.; Wheeler, J. C.; Sarneczky, K.; Szakats, R.; Szalai, T.; Szekely, P.; HETDEX Collaboration

2017-05-01

During the commissioning phase of the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) survey we observed AT 2017byx (ATLAS17bla, PS17bve) at R.A.=14:17:48.36 Dec.=+52:41:54.6 with the Visible Integral-field Replicable Unit Spectrograph (VIRUS) at McDonald Observatory on 2017-04-28.2 UT. The spectrum (range between 3500 and 5500 Angstroms) indicates that AT 2017byx is a Type Ia supernova.

iPTF Discoveries of Recent Type Ia Supernovae

NASA Astrophysics Data System (ADS)

Petrushevska, T.; Ferretti, R.; Fremling, C.; Hangard, L.; Johansson, J.; Migotto, K.; Nyholm, A.; Papadogiannakis, S.; Ben-Ami, S.; De Cia, A.; Dzigan, Y.; Horesh, A.; Leloudas, G.; Manulis, I.; Rubin, A.; Sagiv, I.; Vreeswijk, P.; Yaron, O.; Cao, Y.; Perley, D.; Miller, A.; Waszczak, A.; Kasliwal, M. M.; Hosseinzadeh, G.; Cenko, S. B.; Quimby, R.

2015-05-01

The intermediate Palomar Transient Factory (ATel #4807) reports the discovery and classification of the following Type Ia SNe. Our automated candidate vetting to distinguish a real astrophysical source (1.0) from bogus artifacts (0.0) is powered by three generations of machine learning algorithms: RB2 (Brink et al. 2013MNRAS.435.1047B), RB4 (Rebbapragada et al. 2015AAS...22543402R) and RB5 (Wozniak et al. 2013AAS...22143105W). See ATel #7112 for additional details.

Exposure to arsenic in drinking water is associated with increased prevalence of diabetes: a cross-sectional study in the Zimapán and Lagunera regions in Mexico.

PubMed

Del Razo, Luz M; García-Vargas, Gonzalo G; Valenzuela, Olga L; Castellanos, Erika Hernández; Sánchez-Peña, Luz C; Currier, Jenna M; Drobná, Zuzana; Loomis, Dana; Stýblo, Miroslav

2011-08-24

Human exposures to inorganic arsenic (iAs) have been linked to an increased risk of diabetes mellitus. Recent laboratory studies showed that methylated trivalent metabolites of iAs may play key roles in the diabetogenic effects of iAs. Our study examined associations between chronic exposure to iAs in drinking water, metabolism of iAs, and prevalence of diabetes in arsenicosis-endemic areas of Mexico. We used fasting blood glucose (FBG), fasting plasma insulin (FPI), oral glucose tolerance test (OGTT), glycated hemoglobin (HbA1c), and insulin resistance (HOMA-IR) to characterize diabetic individuals. Arsenic levels in drinking water and urine were determined to estimate exposure to iAs. Urinary concentrations of iAs and its trivalent and pentavalent methylated metabolites were measured to assess iAs metabolism. Associations between diabetes and iAs exposure or urinary metabolites of iAs were estimated by logistic regression with adjustment for age, sex, hypertension and obesity. The prevalence of diabetes was positively associated with iAs in drinking water (OR 1.13 per 10 ppb, p < 0.01) and with the concentration of dimethylarsinite (DMAsIII) in urine (OR 1.24 per inter-quartile range, p = 0.05). Notably, FPI and HOMA-IR were negatively associated with iAs exposure (β -2.08 and -1.64, respectively, p < 0.01), suggesting that the mechanisms of iAs-induced diabetes differ from those underlying type-2 diabetes, which is typically characterized by insulin resistance. Our study confirms a previously reported, but frequently questioned, association between exposure to iAs and diabetes, and is the first to link the risk of diabetes to the production of one of the most toxic metabolites of iAs, DMAsIII.

Exposure to arsenic in drinking water is associated with increased prevalence of diabetes: a cross-sectional study in the Zimapán and Lagunera regions in Mexico

PubMed Central

2011-01-01

Background Human exposures to inorganic arsenic (iAs) have been linked to an increased risk of diabetes mellitus. Recent laboratory studies showed that methylated trivalent metabolites of iAs may play key roles in the diabetogenic effects of iAs. Our study examined associations between chronic exposure to iAs in drinking water, metabolism of iAs, and prevalence of diabetes in arsenicosis-endemic areas of Mexico. Methods We used fasting blood glucose (FBG), fasting plasma insulin (FPI), oral glucose tolerance test (OGTT), glycated hemoglobin (HbA1c), and insulin resistance (HOMA-IR) to characterize diabetic individuals. Arsenic levels in drinking water and urine were determined to estimate exposure to iAs. Urinary concentrations of iAs and its trivalent and pentavalent methylated metabolites were measured to assess iAs metabolism. Associations between diabetes and iAs exposure or urinary metabolites of iAs were estimated by logistic regression with adjustment for age, sex, hypertension and obesity. Results The prevalence of diabetes was positively associated with iAs in drinking water (OR 1.13 per 10 ppb, p < 0.01) and with the concentration of dimethylarsinite (DMAsIII) in urine (OR 1.24 per inter-quartile range, p = 0.05). Notably, FPI and HOMA-IR were negatively associated with iAs exposure (β -2.08 and -1.64, respectively, p < 0.01), suggesting that the mechanisms of iAs-induced diabetes differ from those underlying type-2 diabetes, which is typically characterized by insulin resistance. Conclusions Our study confirms a previously reported, but frequently questioned, association between exposure to iAs and diabetes, and is the first to link the risk of diabetes to the production of one of the most toxic metabolites of iAs, DMAsIII. PMID:21864395

THE SPECTROSCOPIC DIVERSITY OF TYPE Ia SUPERNOVAE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blondin, S.; Matheson, T.; Kirshner, R. P.

2012-05-15

We present 2603 spectra of 462 nearby Type Ia supernovae (SNe Ia), including 2065 previously unpublished spectra, obtained during 1993-2008 through the Center for Astrophysics Supernova Program. There are on average eight spectra for each of the 313 SNe Ia with at least two spectra. Most of the spectra were obtained with the FAST spectrograph at the Fred Lawrence Whipple Observatory 1.5 m telescope and reduced in a consistent manner, making this data set well suited for studies of SN Ia spectroscopic diversity. Using additional data from the literature, we study the spectroscopic and photometric properties of SNe Ia asmore » a function of spectroscopic class using the classification schemes of Branch et al. and Wang et al. The width-luminosity relation appears to be steeper for SNe Ia with broader lines, although the result is not statistically significant with the present sample. Based on the evolution of the characteristic Si II {lambda}6355 line, we propose improved methods for measuring velocity gradients, revealing a larger range than previously suspected, from {approx}0 to {approx}400 km s{sup -1} day{sup -1} considering the instantaneous velocity decline rate at maximum light. We find a weaker and less significant correlation between Si II velocity and intrinsic B - V color at maximum light than reported by Foley et al., owing to a more comprehensive treatment of uncertainties and host galaxy dust. We study the extent of nuclear burning and the presence of unburnt carbon in the outermost layers of the ejecta and report new detections of C II {lambda}6580 in 23 early-time SN Ia spectra. The frequency of C II detections is not higher in SNe Ia with bluer colors or narrower light curves, in conflict with the recent results of Thomas et al. Based on nebular spectra of 27 SNe Ia, we find no relation between the FWHM of the iron emission feature at {approx}4700 A and {Delta}m{sub 15}(B) after removing the two low-luminosity SN 1986G and SN 1991bg, suggesting that the peak luminosity is not strongly dependent on the kinetic energy of the explosion for most SNe Ia. Finally, we confirm the correlation of velocity shifts in some nebular lines with the intrinsic B - V color of SNe Ia at maximum light, although several outliers suggest a possible non-monotonic behavior for the largest blueshifts.« less

Wood-Vasey DOE #SC0011834 Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wood-Vasey, William Michael

During the past reporting period (Year 3), this grant has provided partial support for graduate students Daniel Perrefort and Kara Ponder. They have been working exploring different aspects of the technical work needed to take full advantage of the potential for cosmological inference using Type Ia supernovae (SNeIa) with LSST.

Mid-Infrared Signatures from Type Ia Supernovae Strongly Interacting with a Circumstellar Medium

NASA Astrophysics Data System (ADS)

Fox, Ori

2015-10-01

Type Ia supernovae (SNe Ia) are well-known for their use as precise cosmological distance indicators due to a standardizable peak luminosity resulting from a thermonuclear explosion. A growing subset of SNe Ia, however, show evidence for interaction with a dense circumstellar medium during the first year post-explosion, and sometimes longer (SNe Ia-CSM). The origin of this dense CSM is unknown and suggests either a) the less typical single-degenerate progenitor scenario must be considered or b) the exploding star was not a thermonuclear explosion of a white dwarf at all (i.e., core-collapse). Mid-infrared (IR) observations, in particular, are critical for tracing the density profile of dust (and hence gas) in the surrounding CSM. Yet no Spitzer light curve exists for this subclass within the first year post-expolosion. Here we propose a 'low-impact' (>8 weeks) ToO to obtain 3 epochs of Spitzer imaging of a SN Ia-CSM within 100 Mpc over 1 year post-explosion. The strength of this program is that it will be in conjunction with pre-approved multi-wavelength programs on HST/STIS/UV (GO 13649), Chandra/ASIS-S (Num: 17500672), the Keck/LRIS optical spectrograph (Num: U037LA), and the RATIR visible/infrared robotic imager. Requiring only 2.1 hours of observation total, this program will not only distinguish between the SN explosion mechanisms, but also trace CSM interaction, constrain the progenitor mass loss history, and identify late-time heating mechanisms of warm dust.

Theoretical Clues to the Ultraviolet Diversity of Type Ia Supernovae

NASA Astrophysics Data System (ADS)

Brown, Peter J.; Baron, E.; Milne, Peter; Roming, Peter W. A.; Wang, Lifan

2015-08-01

The effect of metallicity on the observed light of Type Ia supernovae (SNe Ia) could lead to systematic errors as the absolute magnitudes of local and distant SNe Ia are compared to measure luminosity distances and determine cosmological parameters. The UV light may be especially sensitive to metallicity, though different modeling methods disagree as to the magnitude, wavelength dependence, and even the sign of the effect. The outer density structure, 56Ni, and to a lesser degree asphericity, also impact the UV. We compute synthetic photometry of various metallicity-dependent models and compare to UV/optical photometry from the Swift Ultra-Violet/Optical Telescope. We find that the scatter in the mid-UV to near-UV colors is larger than predicted by changes in metallicity alone and is not consistent with reddening. We demonstrate that a recently employed method to determine relative abundances using UV spectra can be done using UVOT photometry, but we warn that accurate results require an accurate model of the cause of the variations. The abundance of UV photometry now available should provide constraints on models that typically rely on UV spectroscopy for constraining metallicity, density, and other parameters. Nevertheless, UV spectroscopy for a variety of supernova explosions is still needed to guide the creation of accurate models. A better understanding of the influences affecting the UV is important for using SNe Ia as cosmological probes, as the UV light may test whether SNe Ia are significantly affected by evolutionary effects.

Trimming of two major type 1 diabetes driving antigens, GAD65 and IA-2, allows for successful expression in Lactococcus lactis.

PubMed

Robert, S; Van Huynegem, K; Gysemans, C; Mathieu, C; Rottiers, P; Steidler, L

2015-01-01

Type 1 diabetes (T1D) is a chronic autoimmune disease characterised by excessive immune reactions against auto-antigens of pancreatic β-cells. Restoring auto-antigen tolerance remains the superior therapeutic strategy. Oral auto-antigen administration uses the tolerogenic nature of the gut-associated immune system to induce antigen-specific tolerance. However, due to gastric degradation, proper mucosal product delivery often imposes a challenge. Recombinant Lactococcus lactis have proven to be effective and safe carriers for gastrointestinal delivery of therapeutic products: L. lactis secreting diabetes-associated auto-antigens in combination with interleukin (IL)-10 have demonstrated therapeutic efficacy in a well-defined mouse model for T1D. Here, we describe the construction of recombinant L. lactis secreting the 65 kDa isoform of glutamic acid decarboxylase (GAD65) and tyrosine phosphatase-like protein ICA512 (IA-2), two major T1D-related auto-antigens. Attempts to secrete full size human GAD65 and IA-2 protein by L. lactis were unsuccessful. Trimming of GAD65 and IA-2 was investigated to optimise antigen secretion while maintaining sufficient bacterial growth. GAD65370-575 and IA-2635-979 showed to be efficiently secreted by recombinant L. lactis. Antigen secretion was verified by immunoblotting. Plasmid-derived GAD65 and IA-2 expression was combined in single strains with human IL-10 expression, a desired combination to allow tolerance induction. This study reports the generation of recombinant L. lactis secreting two major diabetes-related auto-antigens: human GAD65 and IA-2, by themselves or combined with the anti-inflammatory cytokine human IL-10. Prohibitive sequence obstacles hampering antigen secretion were resolved by trimming the full size proteins.

Long-term safety and efficacy of AAV gene therapy in the canine model of glycogen storage disease type Ia.

PubMed

Lee, Young Mok; Conlon, Thomas J; Specht, Andrew; Coleman, Kirsten E; Brown, Laurie M; Estrella, Ana M; Dambska, Monika; Dahlberg, Kathryn R; Weinstein, David A

2018-05-25

Viral mediated gene therapy has progressed after overcoming early failures, and gene therapy has now been approved for several conditions in Europe and the USA. Glycogen storage disease (GSD) type Ia, caused by a deficiency of glucose-6-phosphatase-α, has been viewed as an outstanding candidate for gene therapy. This follow-up report describes the long-term outcome for the naturally occurring GSD-Ia dogs treated with rAAV-GPE-hG6PC-mediated gene therapy. A total of seven dogs were treated with rAAV-GPE-hG6PC-mediated gene therapy. The first four dogs were treated at birth, and three dogs were treated between 2 and 6 months of age to assess the efficacy and safety in animals with mature livers. Blood and urine samples, radiographic studies, histological evaluation, and biodistribution were assessed. Gene therapy improved survival in the GSD-Ia dogs. With treatment, the biochemical studies normalized for the duration of the study (up to 7 years). None of the rAAV-GPE-hG6PC-treated dogs had focal hepatic lesions or renal abnormalities. Dogs treated at birth required a second dose of rAAV after 2-4 months; gene therapy after hepatic maturation resulted in improved efficacy after a single dose. rAAV-GPE-hG6PC treatment in GSD-Ia dogs was found to be safe and efficacious. GSD-Ia is an attractive target for human gene therapy since it is a monogenic disorder with limited tissue involvement. Blood glucose and lactate monitoring can be used to assess effectiveness and as a biomarker of success. GSD-Ia can also serve as a model for other hepatic monogenic disorders.

Functional analysis of T cells expressing Ia antigens. I. Demonstration of helper T-cell heterogeneity.

PubMed

Swierkosz, J E; Marrack, P; Kappler, J W

1979-12-01

We have examined the expression of I-region antigens on functional subpopulations of murine T cells. A.TH anti-A.TL (anti-Ik, Sk, Gk) alloantiserum was raised by immunization of recipients with concanavalin A (Con A) stimulated thymic and peripheral T-cell blasts. In contrast to similar antisera made by conventional methods, the anti-Ia blast serum was highly cytotoxic for purified T lymphocytes. Moreover, it reacted in a specific fashion with T cells having particular functions. Treatment of keyhole limpet hemocyanin (KLH)-primed B10.A (H-2 alpha) T cells with this antiserum plus complement resulted in the elimination of helper activity for B-cell responses to trinitrophenyl-KLH. Inhibition was shown to be a result of the selective killing of one type of helper T cell whose activity could be replaced by a factor(s) found in the supernate of Con A-activated spleen cells. A second type of helper cell required for responses to protein-bound antigens appeared to be Ia-. By absorption and analysis on H-2 recombinants, at least two specificities were detectable on helper T cells; one mapping in the I-A subregion and a second in a region(s) to the right of I-J. In addition, the helper T cell(s) involved in the generation of alloreactive cytotoxic lymphocytes was shown to be Ia+, whereas cytotoxic effector cells and their precursors were Ia- with this antiserum. These results provide strong evidence for the selective expression of I-region determinants on T-cell subsets and suggest that T-cell-associated Ia antigens may play an important role in T-lymphocyte function.

Characterization of Clostridium perfringens iota-toxin genes and expression in Escherichia coli.

PubMed

Perelle, S; Gibert, M; Boquet, P; Popoff, M R

1993-12-01

The iota toxin which is produced by Clostridium perfringens type E, is a binary toxin consisting of two independent polypeptides: Ia, which is an ADP-ribosyltransferase, and Ib, which is involved in the binding and internalization of the toxin into the cell. Two degenerate oligonucleotide probes deduced from partial amino acid sequence of each component of C. spiroforme toxin, which is closely related to the iota toxin, were used to clone three overlapping DNA fragments containing the iota-toxin genes from C. perfringens type E plasmid DNA. Two genes, in the same orientation, coding for Ia (387 amino acids) and Ib (875 amino acids) and separated by 243 noncoding nucleotides were identified. A predicted signal peptide was found for each component, and the secreted Ib displays two domains, the propeptide (172 amino acids) and the mature protein (664 amino acids). The Ia gene has been expressed in Escherichia coli and C. perfringens, under the control of its own promoter. The recombinant polypeptide obtained was recognized by Ia antibodies and ADP-ribosylated actin. The expression of the Ib gene was obtained in E. coli harboring a recombinant plasmid encompassing the putative promoter upstream of the Ia gene and the Ia and Ib genes. Two residues which have been found to be involved in the NAD+ binding site of diphtheria and pseudomonas toxins are conserved in the predicted Ia sequence (Glu-14 and Trp-19). The predicted amino acid Ib sequence shows 33.9% identity with and 54.4% similarity to the protective antigen of the anthrax toxin complex. In particular, the central region of Ib, which contains a predicted transmembrane segment (Leu-292 to Ser-308), presents 45% identity with the corresponding protective antigen sequence which is involved in the translocation of the toxin across the cell membrane.

The minimal promoter region of the dense-core vesicle protein IA-2: transcriptional regulation by CREB.

PubMed

Cai, Tao; Hirai, Hiroki; Xu, Huanyu; Notkins, Abner L

2015-06-01

IA-2 is a transmembrane protein found in the dense-core vesicles (DCV) of neuroendocrine cells and one of the major autoantigens in type 1 diabetes. DCV are involved in the secretion of hormones (e.g., insulin) and neurotransmitters. Stimulation of pancreatic β cells with glucose upregulates the expression of IA-2 and an increase in IA-2 results in an increase in the number of DCV. Little is known, however, about the promoter region of IA-2 or the transcriptional factors that regulate the expression of this gene. In the present study, we constructed eight deletion fragments from the upstream region of the IA-2 transcription start site and linked them to a luciferase reporter. By this approach, we have identified a short bp region (-216 to +115) that has strong promoter activity. We also identified a transcription factor, cAMP responsive element-binding protein (CREB), which binds to two CREB-related binding sites located in this region. The binding of CREB to these sites enhanced IA-2 transcription by more than fivefold. We confirmed these findings by site-directed mutagenesis, chromatin immunoprecipitation assays and RNAi inhibition. Based on these findings, we conclude that the PKA pathway is a critical, but not the exclusive signaling pathway involved in IA-2 gene expression.

Constraining cosmological parameter with SN Ia

NASA Astrophysics Data System (ADS)

Indra Putri, A. N.; Wulandari, H. R. Tri

2016-11-01

A type I supemovae (SN Ia) is an exploding white dwarf, whose mass exceeds Chandrasekar limit (1.44 solar mass). If a white dwarf is in a binary system, it may accrete matter from the companion, resulting in an excess mass that cannot be balanced by the pressure of degenerated electrons in the core. SNe Ia are highly luminous objects, that they are visible from very high distances. After some corrections (stretch (s), colour (c), K-corrections, etc.), the variations in the light curves of SNe Ia can be suppressed to be no more than 10%. Their high luminosity and almost uniform intrinsic brightness at the peak light, i.e. MB ∼ -19, make SNe Ia ideal standard candle. Because of their visibility from large distances, SNe Ia can be employed as a cosmological measuring tool. It was analysis of SNe Ia data that indicated for the first time, that the universe is not only expanding, but also accelerating. This work analyzed a compilation of SNe Ia data to determine several cosmological parameters (H0, Ωm, Ωa, and w). It can be concluded from the analysis, that our universe is a flat, dark energy dominated universe, and that the cosmological constant A is a suitable candidate for dark energy.

Metallicity Differences in Type Ia Supernova Progenitors Inferred from Ultraviolet Spectra

NASA Astrophysics Data System (ADS)

Foley, Ryan J.; Kirshner, Robert P.

2013-05-01

Two "twin" Type Ia supernovae (SNe Ia), SNe 2011by and 2011fe, have extremely similar optical light-curve shapes, colors, and spectra, yet have different ultraviolet (UV) continua as measured in Hubble Space Telescope spectra and measurably different peak luminosities. We attribute the difference in the UV continua to significantly different progenitor metallicities. This is the first robust detection of different metallicities for SN Ia progenitors. Theoretical reasoning suggests that differences in metallicity also lead to differences in luminosity. SNe Ia with higher progenitor metallicities have lower 56Ni yields and lower luminosities for the same light-curve shape. SNe 2011by and 2011fe have different peak luminosities (ΔMV ≈ 0.6 mag), which correspond to different 56Ni yields: M_11fe(^{56}Ni) / M_11by(^{56}Ni) = 1.7^{+0.7}_{-0.5}. From theoretical models that account for different neutron-to-proton ratios in progenitors, the differences in 56Ni yields for SNe 2011by and 2011fe imply that their progenitor stars were above and below solar metallicity, respectively. Although we can distinguish progenitor metallicities in a qualitative way from UV data, the quantitative interpretation in terms of abundances is limited by the present state of theoretical models.

Early UV emission from disc-originated matter (DOM) in Type Ia supernovae in the double-degenerate scenario

NASA Astrophysics Data System (ADS)

Levanon, Naveh; Soker, Noam

2017-09-01

We show that the blue and UV excess emission in the first few days of some Type Ia supernovae (SNe Ia) can be accounted in the double-degenerate (DD) scenario by the collision of the SN ejecta with circumstellar matter that was blown by the accretion disc formed during the merger process of the two white dwarfs (WDs). We assume that in cases of excess early light, the disc blows the circumstellar matter, that we term disc-originated matter (DOM), hours to days before explosion. To perform our analysis, we first provide a model-based definition for early excess light, replacing the definition of excess light relative to a power-law fit to the rising luminosity. We then examine the light curves of the SNe Ia iPTF14atg and SN 2012cg, and find that the collision of the ejecta with a DOM in the frame of the DD scenario can account for their early excess emission. Thus, early excess light does not necessarily imply the presence of a stellar companion in the frame of the single-degenerate scenario. Our findings further increase the variety of phenomena that the DD scenario can account for, and emphasize the need to consider all different SN Ia scenarios when interpreting observations.

A blinded determination of H0 from low-redshift Type Ia supernovae, calibrated by Cepheid variables

NASA Astrophysics Data System (ADS)

Zhang, Bonnie R.; Childress, Michael J.; Davis, Tamara M.; Karpenka, Natallia V.; Lidman, Chris; Schmidt, Brian P.; Smith, Mathew

2017-10-01

Presently, a >3σ tension exists between values of the Hubble constant H0 derived from analysis of fluctuations in the cosmic microwave background by Planck, and local measurements of the expansion using calibrators of Type Ia supernovae (SNe Ia). We perform a blinded re-analysis of Riess et al. (2011) to measure H0 from low-redshift SNe Ia, calibrated by Cepheid variables and geometric distances including to NGC 4258. This paper is a demonstration of techniques to be applied to the Riess et al. (2016) data. Our end-to-end analysis starts from available Harvard -Smithsonian Center for Astrophysics (CfA3) and Lick Observatory Supernova Search (LOSS) photometries, providing an independent validation of Riess et al. (2011). We obscure the value of H0 throughout our analysis and the first stage of the referee process, because calibration of SNe Ia requires a series of often subtle choices, and the potential for results to be affected by human bias is significant. Our analysis departs from that of Riess et al. (2011) by incorporating the covariance matrix method adopted in Supernova Legacy Survey and Joint Lightcurve Analysis to quantify SN Ia systematics, and by including a simultaneous fit of all SN Ia and Cepheid data. We find H_0 = 72.5 ± 3.1 ({stat}) ± 0.77 ({sys}) km s-1 Mpc-1with a three-galaxy (NGC 4258+LMC+MW) anchor. The relative uncertainties are 4.3 per cent statistical, 1.1 per cent systematic, and 4.4 per cent total, larger than in Riess et al. (2011) (3.3 per cent total) and the Efstathiou (2014) re-analysis (3.4 per cent total). Our error budget for H0 is dominated by statistical errors due to the small size of the SN sample, whilst the systematic contribution is dominated by variation in the Cepheid fits, and for the SNe Ia, uncertainties in the host galaxy mass dependence and Malmquist bias.

Strong near-infrared carbon in the Type Ia supernova iPTF13ebh

DOE PAGES

Hsiao, E. Y.; Burns, C. R.; Contreras, C.; ...

2015-05-22

We present near-infrared (NIR) time-series spectroscopy, as well as complementary ultraviolet (UV), optical, and NIR data, of the Type Ia supernova (SN Ia) iPTF13ebh, which was discovered within two days from the estimated time of explosion. The first NIR spectrum was taken merely 2.3 days after explosion and may be the earliest NIR spectrum yet obtained of a SN Ia. The most striking features in the spectrum are several NIR C I lines, and the C Iλ1.0693 μm line is the strongest ever observed in a SN Ia. Interestingly, no strong optical C II counterparts were found, even though themore » optical spectroscopic time series began early and is densely cadenced. Except at the very early epochs, within a few days from the time of explosion, we show that the strong NIR C I compared to the weaker optical C II appears to be general in SNe Ia. iPTF13ebh is a fast decliner with Δm15(B) = 1.79 ± 0.01, and its absolute magnitude obeys the linear part of the width-luminosity relation. It is therefore categorized as a “transitional” event, on the fast-declining end of normal SNe Ia as opposed to subluminous/91bg-like objects. iPTF13ebh shows NIR spectroscopic properties that are distinct from both the normal and subluminous/91bg-like classes, bridging the observed characteristics of the two classes. These NIR observations suggest that composition and density of the inner core are similar to that of 91bg-like events, and that it has a deep-reaching carbon burning layer that is not observed in more slowly declining SNe Ia. Furthermore, there is also a substantial difference between the explosion times inferred from the early-time light curve and the velocity evolution of the Si II λ0.6355 μm line, implying a long dark phase of ~4 days.« less

Stroke in Indigenous Africans, African Americans, and European Americans: Interplay of Racial and Geographic Factors.

PubMed

Owolabi, Mayowa; Sarfo, Fred; Howard, Virginia J; Irvin, Marguerite R; Gebregziabher, Mulugeta; Akinyemi, Rufus; Bennett, Aleena; Armstrong, Kevin; Tiwari, Hemant K; Akpalu, Albert; Wahab, Kolawole W; Owolabi, Lukman; Fawale, Bimbo; Komolafe, Morenikeji; Obiako, Reginald; Adebayo, Philip; Manly, Jennifer M; Ogbole, Godwin; Melikam, Ezinne; Laryea, Ruth; Saulson, Raelle; Jenkins, Carolyn; Arnett, Donna K; Lackland, Daniel T; Ovbiagele, Bruce; Howard, George

2017-05-01

The relative contributions of racial and geographic factors to higher risk of stroke in people of African ancestry have not been unraveled. We compared stroke type and contributions of vascular risk factors among indigenous Africans (IA), African Americans (AA), and European Americans (EA). SIREN (Stroke Investigative Research and Educational Network) is a large multinational case-control study in West Africa-the ancestral home of 71% AA-whereas REGARDS (Reasons for Geographic and Racial Differences in Stroke) is a cohort study including AA and EA in the United States. Using harmonized assessments and standard definitions, we compared data on stroke type and established risk factors for stroke in acute stroke cases aged ≥55 years in both studies. There were 811 IA, 452 AA, and 665 EA stroke subjects, with mean age of 68.0±9.3, 73.0±8.3, and 76.0±8.3 years, respectively ( P <0.0001). Hemorrhagic stroke was more frequent among IA (27%) compared with AA (8%) and EA (5.4%; P <0.001). Lacunar strokes were more prevalent in IA (47.1%), followed by AA (35.1%) and then EA (21.0%; P <0.0001). The frequency of hypertension in decreasing order was IA (92.8%), followed by AA (82.5%) and then EA (64.2%; P <0.0001) and similarly for diabetes mellitus IA (38.3%), AA (36.8%), and EA (21.0%; P <0.0001). Premorbid sedentary lifestyle was similar in AA (37.7%) and EA (34.0%) but lower frequency in IA (8.0%). Environmental risk factors such as sedentary lifestyle may contribute to the higher proportion of ischemic stroke in AA compared with IA, whereas racial factors may contribute to the higher proportion of hypertension and diabetes mellitus among stroke subjects of African ancestry. © 2017 American Heart Association, Inc.

Infrared light curves of type Ia supernovae

DOE PAGES

Phillips, M. M.; Krisciunas, K.; Suntzeff, N. B.; ...

2003-10-02

This article provides a progress report on a collaborative program at the Las Campanas and Cerro Tololo Observatories to observe the near-IR light curves of Type Ia supernovae. We discuss how the morphologies of the JHK light curves change as a function of the decline rate parameter Δm 15 (B). Evidence is presented which indicates that the absolute magnitudes in the H band have little or no dependence on the decline rate, suggesting that SNe Ia may be nearly perfect cosmological standard candles in the near-IR. A preliminary Hubble diagram in the H band is presented and compared with amore » similar diagram in V for the same objects. Finally, observations of two peculiar supernovae, 1999ac and 2001ay, are briefly discussed.« less

CONSTRAINING THE SPIN-DOWN TIMESCALE OF THE WHITE DWARF PROGENITORS OF TYPE Ia SUPERNOVAE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meng, Xiangcun; Podsiadlowski, Philipp, E-mail: xiangcunmeng@hotmail.com

2013-12-01

Justham and Di Stefano et al. proposed that the white dwarf progenitor of a Type Ia supernova (SN Ia) may have to spin down before it can explode. As the white dwarf spin-down timescale is not well known theoretically, here we try to constrain it empirically (within the framework of this spin-down model) for progenitor systems that contain a giant donor and for which circumbinary material has been detected after the explosion: we obtain an upper limit of a few 10{sup 7}yr. Based on the study of Di Stefano and Kilic, this means that it is too early to rulemore » out the existence of a surviving companion in SNR 0509–67.5.« less

The Melbourne Pre-Diabetes Study: prediction of type 1 diabetes mellitus using antibody and metabolic testing.

PubMed

Colman, P G; McNair, P; Margetts, H; Schmidli, R S; Werther, G A; Alford, F P; Ward, G M; Tait, B D; Honeyman, M C; Harrison, L C

1998-07-20

To determine the utility of various autoantibodies in predicting progression to clinical diabetes in first-degree relatives of patients with type 1 diabetes mellitus. 3315 first-degree relatives of patients with type 1 diabetes (1161 parents, 1206 siblings and 948 offspring) recruited through diabetes clinics, private endocrinologists, Diabetes Australia and the Juvenile Diabetes Foundation. Prevalence of islet cell antibodies (ICA) levels > or = 20 JDFu, insulin autoantibodies (IAA) levels > 100 nU/mL, and antibodies to glutamic acid decarboxylase (GADAb) and tyrosine phosphatase IA2 (IA2Ab); change in beta cell function over time; and development of clinical diabetes. 2.6% of relatives had elevated ICA levels, 1.3% had elevated IAA levels and 0.3% had both. High ICA levels were significantly more frequent in siblings than in offspring or parents, and were more frequent in relatives younger than 20 years. GADAb were detected in 68% and IA2Ab in 57% of relatives with elevated ICA and/or IAA levels. Diabetes developed in 33 relatives (25 siblings, 2 offspring and 6 parents). Before diagnosis of clinical diabetes, high ICA levels were detected in 18 (58%), high IAA levels in 7 (23%), both in 5 (15%), and either in 19 (61%); GADAb were detected in 26 (84%), IA2Ab in 13 (42%), both in 11 (35%), and either in 28 (90%). First phase insulin release (FPIR) less than 50 mU/L was very strongly associated with progression to diabetes. In relatives with FPIR initially greater than 50 mU/L who eventually developed diabetes, there was a gradual and continuous reduction in FPIR over time before diagnosis. Type 1 diabetes can be diagnosed in the preclinical stage. The recently described antibodies to glutamic acid decarboxylase and tyrosine phosphatase IA2 appear superior to ICA as screening tools for the preclinical diagnosis of type 1 diabetes.

Assessing the quality of the ecological component of English Environmental Statements.

PubMed

Drayson, Katherine; Wood, Graham; Thompson, Stewart

2015-09-01

Environmental Impact Assessment (EIA) is a key tool to help ensure sustainable built development in more than 200 countries worldwide. Ecology is frequently a component of EIA and early reviews of Ecological Impact Assessment (EcIA) chapters identified scope for improvement at almost every stage of the EcIA process, regardless of country. However, there have been no reviews of UK EcIA chapters since 2000, despite important changes in biodiversity and planning legislation, policy and guidance. In addition, no UK EcIA chapter reviews have attempted to assign a grade or score to EcIA chapters (as has been done for reviews of US, Finnish and Indian EcIA chapters). Furthermore, no EcIA chapter reviews have attempted to use a scoring system to identify which variables determine EcIA chapter information content, beyond straightforward comparisons of EcIA chapters before and after the introduction of guidelines. A variant of the Biodiversity Assessment Index (BAI) was used to assign scores between zero and one to EcIA chapters based on a series of 47 questions drawn from EU legislation and professional guidance. 112 EcIA chapters for proposed developments that were subsequently granted planning permission in England were assessed. The mean BAI score was less than 0.5, indicating the presence of considerable information gaps in the majority of EcIA chapters. Of 13 predictor variables identified as having the potential to affect EcIA chapter quality, 10 were identified as significantly related to the BAI scores. A backward stepwise Generalized Linear Model identified the use of professional guidance, the ecological consultancy type and the length of the EcIA chapter as having the greatest combined explanatory power. As a result, several recommendations are made to help improve future EcIA chapter content, including formal EcIA chapter review, publicising the professional guidance to consultants, the provision of training and the introduction of an accreditation scheme for consultants involved in EcIA This approach could be replicated in other countries that conduct EIA. Context-dependent EcIA chapter review criteria (as in this paper) would help to identify targeted recommendations for improvement. Alternatively, a global set of review criteria could highlight areas of best practice that could then be exported to other countries. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

Disrupted inter-hemispheric functional and structural coupling in Internet addiction adolescents.

PubMed

Bi, Yanzhi; Yuan, Kai; Feng, Dan; Xing, Lihong; Li, Yangding; Wang, Hongmei; Yu, Dahua; Xue, Ting; Jin, Chenwang; Qin, Wei; Tian, Jie

2015-11-30

Rapid progress had been made towards the effect of Internet addiction (IA) on the adolescents brain, relatively little is known about the alterations in inter-hemispheric resting state functional connectivity (RSFC) changes. In the current study, voxel-mirrored homotopic connectivity (VMHC) was used to examine inter-hemispheric RSFC in IA adolescents (n=21) and controls (n=21). The integrity of the fibers connecting the regions, which showed aberrant inter-hemispheric functional connectivity, was assessed by fiber tractography analysis. In addition, the coupling of inter-hemispheric functional and structural connectivity was investigated. Relative to controls, IA adolescents showed decreased VMHC of dorsolateral prefrontal cortex (DLPFC) and reduced fractional anisotropy (FA) values in the genu of corpus callosum (CC). The decreased VMHC of DLPFC was significantly negative correlated with the duration of IA. Moreover, the VMHC of DLPFC showed significant correlations with the FA of CC in healthy controls, which was disrupted in IA. Our findings provided more scientific evidence for the involvement of DLPFC in IA. It is hoped that multimodal imaging methods can provide deeper insights into the IA effects on the brain. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

A different class of Ia supernovae?

NASA Astrophysics Data System (ADS)

Horesh, Assaf; Hancock, Paul; Kulkarni, S. R.; Strom, Allison; Gal-Yam, Avishay; Patat, Ferdinando; Goobar, Ariel; Sullivan, Mark; Sternberg, Assaf; Maguire, Kate; Cao, Yi

2014-04-01

Type Ia supernovae (SNe Ia) have become well known due to their use as distance estimators for cosmology, yet the nature of their progenitor systems is a matter of hot debate. The two main models are single-degenerate systems (SD) where a white dwarf accretes material from a main sequence or giant companion, and a double-degenerate (DD) merger of two white dwarf stars. Several recent publications have placed stringent upper limits on predicted signatures of SD systems, suggesting some individual events are more likely to be DD explosions. At the same time, other papers show direct evidence for circumstellar material (CSM) around other SNe Ia, favoring SD origins for these explosions. The emerging picture is of a non-uniform population of SNe Ia, arising from a mix of both the SD and DD channels. Here, we propose a focused radio program targeted only at rare nearby SNe Ia that show signatures of CSM (likely SD origin) in their optical spectra. The detection of even one such CSM-rich SN Ia event would be a breakthrough discovery. We provide estimates showing that such detection is possible, and motivate this focused approach over previous "blind" large programs.

Factors associated with Internet addiction: Cross-sectional study of Turkish adolescents.

PubMed

Seyrek, Sezen; Cop, Esra; Sinir, Hayati; Ugurlu, Mehmet; Şenel, Saliha

2017-02-01

The aim of this study was to investigate the prevalence of Internet addiction (IA), and the relationship between sociodemographic characteristics, depression, anxiety, attention-deficit-hyperactivity disorder (ADHD) symptoms and IA in adolescents. This was a cross-sectional school-based study with a representative sample of 468 students aged 12-17 years at the first trimester of the 2013-2014 academic year. The students were assessed using Young's Internet Addiction Scale, Children's Depression Inventory, Beck Anxiety Inventory, Conners' Parent Rating Scale, Conners' Teacher Rating Scale, Hollingshead-Redlich Scale, and the information form including characteristics of Internet use and socioeconomic status (SES). The relationship between these factors and Internet use was examined. Approximately 1.6% of students were identified as having IA, whereas 16.2% had possible IA. There were significant correlations between IA and depression, anxiety, attention disorder and hyperactivity symptoms in adolescents. Smoking was also related to IA. There was no significant relationship between IA and age, sex, body mass index, school type, and SES. Depression, anxiety, ADHD and smoking addiction are associated with PIU in adolescent students. Preventive public health policies targeting the psychological wellbeing of young people are needed. © 2016 Japan Pediatric Society.

Immunophenotypes of macular corneal dystrophy in India and correlation with mutations in CHST6

PubMed Central

Klintworth, Gordon K.; Thonar, Eugene J-M.A.; Vemuganti, Geeta K.; Kannabiran, Chitra

2009-01-01

Purpose To determine the immunophenotypes of macular corneal dystrophy (MCD) in Indian patients and to correlate them with mutations in the carbohydrate 6-sulfotransferase (CHST6) gene. Methods Sixty-four patients from 53 families with MCD that were previously screened for mutations in CHST6 were included in an immunophenotype analysis. Antigenic keratan sulfate (AgKS) in serum as well as corneal tissue was evaluated in 31 families. Only cornea was evaluated in 11 families, and only serum was evaluated in 11 families. AgKS was detected in formalin-fixed, paraffin-embedded corneal sections by immunohistochemistry and in serum by ELISA using a monoclonal antibody against sulfated forms of KS in patients with MCD as well as normal controls. Results Analysis of corneal and/or serum AgKS disclosed MCD type I (27 families), MCD type IA (5 families), and MCD type II (3 families) in the cases studied. An additional 10 families were either MCD type I or MCD type IA since only serum AgKS data were available. Seven families manifested atypical immunophenotypes since the corneal AgKS expression was either of MCD type I or MCD type IA, but serum AgKS levels ranged from 19 ng/ml to 388 ng/ml. More than one immunophenotype was detected amongst siblings in two families. Each immunophenotype was associated with mutational heterogeneity in CHST6. Conclusions MCD type I was the predominant immunophenotype in the Indian population studied followed by MCD type IA and then MCD type II. We detected further immunophenotypic heterogeneity by finding atypical patterns of AgKS reactivity in a subset of families. There were no simple correlations between immunophenotypes and specific mutations in CHST6, suggesting that factors other than CHST6 mutations may be contributing to the immunophenotypes in MCD. PMID:19204788

Spectroscopic Classification of SN 2017ghm as a Type Ia Supernova

NASA Astrophysics Data System (ADS)

Vinko, J.; Wheeler, J. C.; Wang, X.; Li, W.; Li, Z.; Xiang, D.; Rui, L.; Lin, H.; Xu, Z.; Li, B.; Zhao, H.; Wang, L.; Tan, H.; Zhang, J.

2017-09-01

An optical spectrum (range 360-680 nm) of SN 2017ghm (=PTSS-17uyml), discovered by the PMO-Tsinghua Supernova Survey (PTSS, http://www.cneost.org/ptss/), was obtained with the new "Low Resolution Spectrograph-2" (LRS2) on the 10m Hobby-Eberly Telescope at McDonald Observatory by S. Rostopchin on 2017 Aug 31.17 UT. The spectrum is consistent with that of a heavily reddened Type Ia supernova (with Av > 2.3 mag) around maximum light.

Soft x-ray imager (SXI) onboard the NeXT satellite

NASA Astrophysics Data System (ADS)

Tsuru, Takeshi Go; Takagi, Shin-Ichiro; Matsumoto, Hironori; Inui, Tatsuya; Ozawa, Midori; Koyama, Katsuji; Tsunemi, Hiroshi; Hayashida, Kiyoshi; Miyata, Emi; Ozawa, Hideki; Touhiguchi, Masakuni; Matsuura, Daisuke; Dotani, Tadayasu; Ozaki, Masanobu; Murakami, Hiroshi; Kohmura, Takayoshi; Kitamoto, Shunji; Awaki, Hisamitsu

2006-06-01

We give overview and the current status of the development of the Soft X-ray Imager (SXI) onboard the NeXT satellite. SXI is an X-ray CCD camera placed at the focal plane detector of the Soft X-ray Telescopes for Imaging (SXT-I) onboard NeXT. The pixel size and the format of the CCD is 24 x 24μm (IA) and 2048 x 2048 x 2 (IA+FS). Currently, we have been developing two types of CCD as candidates for SXI, in parallel. The one is front illumination type CCD with moderate thickness of the depletion layer (70 ~ 100μm) as a baseline plan. The other one is the goal plan, in which we develop back illumination type CCD with a thick depletion layer (200 ~ 300μm). For the baseline plan, we successfully developed the proto model 'CCD-NeXT1' with the pixel size of 12μm x 12μm and the CCD size of 24mm x 48mm. The depletion layer of the CCD has reached 75 ~ 85μm. The goal plan is realized by introduction of a new type of CCD 'P-channel CCD', which collects holes in stead of electrons in the common 'N-channel CCD'. By processing a test model of P-channel CCD we have confirmed high quantum efficiency above 10 keV with an equivalent depletion layer of 300μm. A back illumination type of P-channel CCD with a depletion layer of 200μm with aluminum coating for optical blocking has been also successfully developed. We have been also developing a thermo-electric cooler (TEC) with the function of the mechanically support of the CCD wafer without standoff insulators, for the purpose of the reduction of thermal input to the CCD through the standoff insulators. We have been considering the sensor housing and the onboard electronics for the CCD clocking, readout and digital processing of the frame date.

[Internet Addiction, Suicidality and Non-Suicidal Self-Harming Behavior - A Systematic Review].

PubMed

Steinbüchel, Toni Andreas; Herpertz, Stephan; Külpmann, Ina; Kehyayan, Aram; Dieris-Hirche, Jan; Te Wildt, Bert Theodor

2017-11-23

Background Internet addiction (IA) is associated with a high rate of co-morbid mental disorders, especially depression, anxiety disorders, ADHD and personality disorders and a considerable level of psychological strain. In terms of risk assessment, the present work investigates the current research literature on suicidal behavior and non-suicidal self-injurious behavior (NSSI). Methods We performed a systematic literature search in 14 databases on title and abstract level for the most common keywords for IA, NSSI and suicidality. After deduction of multiple items, 2334 articles remained. They were filtered per inclusion and exclusion criteria. We identified studies that examined the relationship between IA, NSSI and suicidality, which were assessed by validated psychometric instruments. This allowed a total of 15 studies to be included. Results The relationship between IA and suicidality was examined in 10 studies, four studies examined the relationship of IA, suicidality, and NSSI, and one study exclusively focused on IA and NSSHB. All studies showed higher prevalence for NSSI and respectively suicidality of the subjects with an IA compared to subjects without IA, with point prevalence varying considerably between 1.6-18.7%. Discussion The results of the included publications suggest that Internet dependency is associated with an increased rate of non-suicidal self-harming behavior and increased suicidality, with suicidal ideation being more closely related to IA than suicidal actions. In order to develop a better understanding of causal relationships between IA, NSSI and suicidality, further longitudinal studies are required. Conclusion  Against the background of the presented studies NSSHB and suicidality need to be explicitly addressed within the assessment and treatment of IA patients. © Georg Thieme Verlag KG Stuttgart · New York.

A novel homozygous no-stop mutation in G6PC gene from a Chinese patient with glycogen storage disease type Ia.

PubMed

Gu, Lei-Lei; Li, Xin-Hua; Han, Yue; Zhang, Dong-Hua; Gong, Qi-Ming; Zhang, Xin-Xin

2014-02-25

Glycogen storage disease type Ia (GSD-Ia) is an autosomal recessive genetic disorder resulting in hypoglycemia, hepatomegaly and growth retardation. It is caused by mutations in the G6PC gene encoding Glucose-6-phosphatase. To date, over 80 mutations have been identified in the G6PC gene. Here we reported a novel mutation found in a Chinese patient with abnormal transaminases, hypoglycemia, hepatomegaly and short stature. Direct sequencing of the coding region and splicing-sites in the G6PC gene revealed a novel no-stop mutation, p.*358Yext*43, leading to a 43 amino-acid extension of G6Pase. The expression level of mutant G6Pase transcripts was only 7.8% relative to wild-type transcripts. This mutation was not found in 120 chromosomes from 60 unrelated healthy control subjects using direct sequencing, and was further confirmed by digestion with Rsa I restriction endonuclease. In conclusion, we revealed a novel no-stop mutation in this study which expands the spectrum of mutations in the G6PC gene. The molecular genetic analysis was indispensable to the diagnosis of GSD-Ia for the patient. Copyright © 2013 Elsevier B.V. All rights reserved.

Left Behind: A Bound Remnant from a White Dwarf Supernova?

NASA Astrophysics Data System (ADS)

Jha, Saurabh

2017-08-01

Type Ia supernovae (SN Ia) have enormous importance to cosmology and astrophysics, but their progenitors and explosion mechanisms are not understood in detail. Recently, observations and theoretical models have suggested that not all thermonuclear white-dwarf supernova explosions are normal SN Ia. In particular, type Iax supernovae (peculiar cousins to SN Ia), are thought to be exploding white dwarfs that are not completely disrupted, leaving behind a bound remnant. In deep and serendipitous HST pre-explosion data, we have discovered a luminous, blue progenitor system for the type Iax SN 2012Z in NGC 1309, which we interpret as a helium-star donor to the exploding white dwarf. HST observations of SN 2012Z in 2016, when the supernova light was expected to have faded away, still show a source at the location, as expected in our model where the pre-explosion flux was coming from the companion. However, the 2016 data also show a surprise: an excess flux compared to the progenitor system. Our proposed observations here will help unravel the mystery of that excess flux: is it from the bound ex-white dwarf remnant? Or is it from the shocked companion star that has been bombarded by supernova ejecta? Either of these possibilities would provide key new evidence as to the nature of these white dwarf supernovae.

National Program for Inspection of Non-Federal Dams. Spectacle Swamp Dam (CT 00476), Connecticut Coastal Basin, Wilton, Connecticut. Phase I Inspection Report.

DTIC Science & Technology

1981-05-01

CT 00476 IA 𔄁V 7 4. TITLE (nd $ba#ile) S. TYPE OF REPORT a PERIOD COVERED Spectacle Swamp Dam INSPECTION REPORT NATIONAL PROGRAM FOR INSPECTION OF...PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELrihENT. PROJECT. TASK AREA & WORK UNIT NUMS1RS X 1I. CONTROLLING OFFICE NAME AND ADDRESS Ia ...SCNEDULE 16. DISTRIOUTION STATEMENT (1 tklReport) APPROVAL FOR PUBLIC RELEASE: DISTRIBUTION UNLIMITED 5 17. DISTRIOUTION STATEMENT (of IA * he r ieet

Recognition and categorization considerations for information assurance requirements development and speficication

NASA Astrophysics Data System (ADS)

Stytz, Martin R.; May, Michael; Banks, Sheila B.

2009-04-01

Department of Defense (DoD) Information Technology (IT) systems operate in an environment different from the commercial world, the differences arise from the differences in the types of attacks, the interdependencies between DoD software systems, and the reliance upon commercial software to provide basic capabilities. The challenge that we face is determining how to specify the information assurance requirements for a system without requiring changes to the commercial software and in light of the interdependencies between systems. As a result of the interdependencies and interconnections between systems introduced by the global information grid (GIG), an assessment of the IA requirements for a system must consider three facets of a system's IA capabilities: 1) the IA vulnerabilities of the system, 2) the ability of a system to repel IA attacks, and 3) the ability of a system to insure that any IA attack that penetrates the system is contained within the system and does not spread. Each facet should be assessed independently and the requirements should be derived independently from the assessments. In addition to the desired IA technology capabilities of the system, a complete assessment of the system's overall IA security technology readiness level cannot be accomplished without an assessment of the capabilities required of the system for its capability to recover from and remediate IA vulnerabilities and compromises. To allow us to accomplish these three formidable tasks, we propose a general system architecture designed to separate the system's IA capabilities from its other capability requirements; thereby allowing the IA capabilities to be developed and assessed separately from the other system capabilities. The architecture also enables independent requirements specification, implementation, assessment, measurement, and improvement of a system's IA capabilities without requiring modification of the underlying application software.

Inclusion Assistants in General Education Settings--A Model for In-Service Training

ERIC Educational Resources Information Center

Moshe, Anat

2017-01-01

The inclusion assistant (IA) is a fairly new position in the education system and is the outcome of current ideological and legislative steps to include students with special needs into the general educational system. The IA's function is to personally accompany students with severe disabilities--autism, developmental disabilities, physical…

Ninety six well microtiter plate as microbioreactors for production of itaconic acid by six Aspergillus terreus strains

USDA-ARS?s Scientific Manuscript database

Itaconic acid (IA) is a building block platform chemical that is currently produced industrially from glucose by fermentation with Aspergillus terreus. However, lignocellulosic biomass has the potential to serve as low cost source of sugars for production of IA. Previously, 100 A. terreus strains we...

Long-term outcome of anti-glomerular basement membrane antibody disease treated with immunoadsorption.

PubMed

Biesenbach, Peter; Kain, Renate; Derfler, Kurt; Perkmann, Thomas; Soleiman, Afschin; Benharkou, Alexandra; Druml, Wilfred; Rees, Andrew; Säemann, Marcus D

2014-01-01

Anti-glomerular basement membrane (GBM) antibody disease may lead to acute crescentic glomerulonephritis with poor renal prognosis. Current therapy favours plasma exchange (PE) for removal of pathogenic antibodies. Immunoadsorption (IAS) is superior to PE regarding efficiency of antibody-removal and safety. Apart from anecdotal data, there is no systemic analysis of the long-term effects of IAS on anti-GBM-disease and antibody kinetics. To examine the long-term effect of high-frequency IAS combined with standard immunosuppression on patient and renal survival in patients with anti-GBM-disease and to quantify antibody removal and kinetics through IAS. Retrospective review of patients treated with IAS for anti-GBM-antibody disease confirmed by biopsy and/or anti-GBM-antibodies. University Hospital of Vienna, Austria. 10 patients with anti-GBM-disease treated with IAS. Patient and renal survival, renal histology, anti-GBM-antibodies. Anti-GBM-antibodies were reduced by the first 9 IAS treatments (mean number of 23) to negative levels in all patients. Renal survival was 40% at diagnosis, 70% after the end of IAS, 63% after one year and 50% at the end of observation (mean 84 months, range 9 to 186). Dialysis dependency was successfully reversed in three of six patients. Patient survival was 90% at the end of observation. IAS efficiently eliminates anti-GBM-antibodies suggesting non-inferiority to PE with regard to renal and patient survival. Hence IAS should be considered as a valuable treatment option for anti-GBM-disease, especially in patients presenting with a high percentage of crescents and dialysis dependency due to an unusual high proportion of responders.

Early Observations of the Type Ia Supernova iPTF 16abc

NASA Astrophysics Data System (ADS)

Miller, Adam; iPTF Collaboration

2018-01-01

Early observations of Type Ia supernovae (SNe) provide a unique probe of their progenitor systems and explosion physics. Here, we report the intermediate Palomar Transient Factory (iPTF) discovery of an extraordinarily young SN Ia, iPTF 16abc. By fitting a power law to our early light curve, we infer that first light for the SN only occurred 0.15 +0.15-0.07 d before our first detection. In the ~24 hr after discovery, iPTF 16abc rose by ~2 mag, following a near-linear rise in flux for ~3 d. Strong C II absorption is detected in the early spectra of iPTF 16abc, before disappearing after ~7 d. Unlike the extensively-observed Type Ia SN 2011fe, the (B-V)_0 colors of iPTF 16abc are blue and nearly constant in the days after explosion. We show that our early observations of iPTF 16abc cannot be explained by either SN shock breakout and the associated, subsequent cooling, or the SN ejecta colliding with a stellar companion. Instead, we argue that the early characteristics of iPTF 16abc, including: (i) the rapid, near-linear rise, (ii) the non-evolving blue colors, and (iii) the strong absorption from ionized carbon, are the result of either vigorous mixing of radioactive-Ni in the SN ejecta, or ejecta interaction with diffuse material, or a combination of the two. In the next few years, dozens of very young normal SNe Ia will be discovered, and observations similar to those presented here will constrain the white dwarf explosion mechanism.

High Potency of Indolyl Aryl Sulfone Nonnucleoside Inhibitors towards Drug-Resistant Human Immunodeficiency Virus Type 1 Reverse Transcriptase Mutants Is Due to Selective Targeting of Different Mechanistic Forms of the Enzyme

PubMed Central

Cancio, Reynel; Silvestri, Romano; Ragno, Rino; Artico, Marino; De Martino, Gabriella; La Regina, Giuseppe; Crespan, Emmanuele; Zanoli, Samantha; Hübscher, Ulrich; Spadari, Silvio; Maga, Giovanni

2005-01-01

Indolyl aryl sulfone (IAS) nonnucleoside inhibitors have been shown to potently inhibit the growth of wild-type and drug-resistant human immunodeficiency virus type 1 (HIV-1), but their exact mechanism of action has not been elucidated yet. Here, we describe the mechanism of inhibition of HIV-1 reverse transcriptase (RT) by selected IAS derivatives. Our results showed that, depending on the substitutions introduced in the IAS common pharmacophore, these compounds can be made selective for different enzyme-substrate complexes. Moreover, we showed that the molecular basis for this selectivity was a different association rate of the drug to a particular enzymatic form along the reaction pathway. By comparing the activities of the different compounds against wild-type RT and the nonnucleoside reverse transcriptase inhibitor-resistant mutant Lys103Asn, it was possible to hypothesize, on the basis of their mechanism of action, a rationale for the design of drugs which could overcome the steric barrier imposed by the Lys103Asn mutation. PMID:16251294

Clostridium perfringens Iota Toxin: Binding Studies and Characterization of Cell Surface Receptor by Fluorescence-Activated Cytometry

PubMed Central

Stiles, Bradley G.; Hale, Martha L.; Marvaud, Jean-Christophe; Popoff, Michel R.

2000-01-01

The binding characteristics of iota toxin, a binary enterotoxin produced by Clostridium perfringens type E, were studied by fluorescence-activated cytometry. The proteolytically activated binding component of iota toxin, iota b (Ib), bound to various cell types when incubated at 4, 25, or 37°C for 10 min. The binding of Ib was inhibited by antisera against C. perfringens type E or Clostridium spiroforme culture supernatants, but not C. perfringens types C or D. Pretreatment of Vero cells with glycosidases or lectins did not affect Ib interactions, while pronase effectively prevented Ib binding to the cell surface. The Ib protomer (Ibp) bound to the cell surface, but trypsinization of Ibp was necessary for docking of the ADP-ribosylating component, iota a (Ia). Ia attached to cell-bound Ib within 10 min at 37°C, but surface levels of Ia decreased 90% after 30 min and were undetectable by 60 min. Detectable surface levels of Ib also diminished over time, and Western blot analysis suggested internalization or embedment of Ib into the membrane. PMID:10816501

Clostridium perfringens iota toxin: binding studies and characterization of cell surface receptor by fluorescence-activated cytometry.

PubMed

Stiles, B G; Hale, M L; Marvaud, J C; Popoff, M R

2000-06-01

The binding characteristics of iota toxin, a binary enterotoxin produced by Clostridium perfringens type E, were studied by fluorescence-activated cytometry. The proteolytically activated binding component of iota toxin, iota b (Ib), bound to various cell types when incubated at 4, 25, or 37 degrees C for 10 min. The binding of Ib was inhibited by antisera against C. perfringens type E or Clostridium spiroforme culture supernatants, but not C. perfringens types C or D. Pretreatment of Vero cells with glycosidases or lectins did not affect Ib interactions, while pronase effectively prevented Ib binding to the cell surface. The Ib protomer (Ibp) bound to the cell surface, but trypsinization of Ibp was necessary for docking of the ADP-ribosylating component, iota a (Ia). Ia attached to cell-bound Ib within 10 min at 37 degrees C, but surface levels of Ia decreased 90% after 30 min and were undetectable by 60 min. Detectable surface levels of Ib also diminished over time, and Western blot analysis suggested internalization or embedment of Ib into the membrane.

Using large spectroscopic surveys to test the double degenerate model for Type Ia supernovae

NASA Astrophysics Data System (ADS)

Breedt, E.; Steeghs, D.; Marsh, T. R.; Gentile Fusillo, N. P.; Tremblay, P.-E.; Green, M.; De Pasquale, S.; Hermes, J. J.; Gänsicke, B. T.; Parsons, S. G.; Bours, M. C. P.; Longa-Peña, P.; Rebassa-Mansergas, A.

2017-07-01

An observational constraint on the contribution of double degenerates to Type Ia supernovae requires multiple radial velocity measurements of ideally thousands of white dwarfs. This is because only a small fraction of the double degenerate population is massive enough, with orbital periods short enough, to be considered viable Type Ia progenitors. We show how the radial velocity information available from public surveys such as the Sloan Digital Sky Survey can be used to pre-select targets for variability, leading to a 10-fold reduction in observing time required compared to an unranked or random survey. We carry out Monte Carlo simulations to quantify the detection probability of various types of binaries in the survey and show that this method, even in the most pessimistic case, doubles the survey size of the largest survey to date (the SPY Survey) in less than 15 per cent of the required observing time. Our initial follow-up observations corroborate the method, yielding 15 binaries so far (eight known and seven new), as well as orbital periods for four of the new binaries.

Remission of insulin autoimmune syndrome in a patient with Grave's disease by treatment with methimazole.

PubMed

Okabe, R; Inaba, M; Hosoi, M; Ishimura, E; Kumeda, Y; Nishizawa, Y; Morii, H

1999-06-01

The patient, a 24-year-old man, had suffered from hunger, sweating, tachycardia and palpitation for three years. He was diagnosed as having Graves' disease (GD) and treated with methimazole (MMI) for 3 months. He noted that palpitation and perspiration seemed to particularly occur when he was hungry, and thus he was examined to determine whether these symptoms were caused by hypoglycemia. As a markedly elevated immunoreactive insulin level and the presence of insulin antibody in serum were found, he was diagnosed as having insulin autoimmune syndrome (IAS). HLA typing revealed the patient to be positive for group Bw62/Cw4/DR4, which is reportedly a specific HLA type in MMI-treated euthyoroid GD patients with IAS. In spite of the continuation of MMI treatment, the % binding of IRI decreased and the hypoglycemic episode disappeared. In contrast to the previously reported MMI induced IAS in GD cases, MMI is unlikely to have exacerbated IAS in the present case, although his HLA combination is identical to that of the previous cases.

Identification of a novel mutation in a patient with pseudohypoparathyroidism type Ia

PubMed Central

Lee, Ye Seung; Kim, Hui Kwon; Kim, Hye Rim; Lee, Jong Yoon; Choi, Joong Wan; Bae, Eun Ju; Oh, Phil Soo; Park, Won Il; Ki, Chang Seok

2014-01-01

Pseudohypoparathyroidism type Ia (PHP Ia) is a disorder characterized by multiform hormonal resistance including parathyroid hormone (PTH) resistance and Albright hereditary osteodystrophy (AHO). It is caused by heterozygous inactivating mutations within the Gs alpha-encoding GNAS exons. A 9-year-old boy presented with clinical and laboratory abnormalities including hypocalcemia, hyperphosphatemia, PTH resistance, multihormone resistance and AHO (round face, short stature, obesity, brachydactyly and osteoma cutis) which were typical of PHP Ia. He had a history of repeated convulsive episodes that started from the age of 2 months. A cranial computed tomography scan showed bilateral calcifications in the basal ganglia and his intelligence quotient testing indicated mild mental retardation. Family history revealed that the patient's maternal relatives, including his grandmother and 2 of his mother's siblings, had features suggestive of AHO. Sequencing of the GNAS gene of the patient identified a heterozygous nonsense mutation within exon 11 (c.637 C>T). The C>T transversion results in an amino acid substitution from Gln to stop codon at codon 213 (p.Gln213*). To our knowledge, this is a novel mutation in GNAS. PMID:25045367

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamaguchi, Hiroya; Badenes, Carles; Foster, Adam R.

Despite decades of intense efforts, many fundamental aspects of Type Ia supernovae (SNe Ia) remain elusive. One of the major open questions is whether the mass of an exploding white dwarf (WD) is close to the Chandrasekhar limit. Here, we report the detection of strong K-shell emission from stable Fe-peak elements in the Suzaku X-ray spectrum of the Type Ia supernova remnant (SNR) 3C 397. The high Ni/Fe and Mn/Fe mass ratios (0.11–0.24 and 0.018–0.033, respectively) in the hot plasma component that dominates the K-shell emission lines indicate a degree of neutronization in the supernova ejecta that can only bemore » achieved by electron capture in the dense cores of exploding WDs with a near-Chandrasekhar mass. This suggests a single-degenerate origin for 3C 397, since Chandrasekhar mass progenitors are expected naturally if the WD accretes mass slowly from a companion. Altogether with other results supporting the double-degenerate scenario, our work adds to the mounting evidence that both progenitor channels make a significant contribution to the SN Ia rate in star-forming galaxies.« less

Studing the Post Merger Evolution of White Dwarf Mergers with FLASH

NASA Astrophysics Data System (ADS)

Jenks, Malia

2017-06-01

There is still uncertainty as to the progenitor systems of type Ia supernova (SN Ia). Both single and double degenerate systems have been suggested as progenitors. In a double degenerate system a merger between the two white dwarfs, with total mass at or exceeding the Chandrasekhar mass, leads to the supernova. If the explosion occurs during the merging process it is a violent merger. If an explosion doesn't occur while the stars merge the system becomes a white dwarf of unstable mass. For mergers of this type with differing starting masses it has been shown that during the viscous evolution carbon burning starts far from the center and stably converts the star to oxygen and neon. In this case the star will eventually collapse to a neutron star and not produce an SN Ia. The case of similar mass mergers has been much less explored. Using the results of a smooth particle hydrodynamic merger we simulate the viscous evolution of an equal mass model with FLASH. These simulations test if a similar mass merger can lead to an SN Ia.

Focal cortical dysplasias: surgical outcome in 67 patients in relation to histological subtypes and dual pathology.

PubMed

Fauser, Susanne; Schulze-Bonhage, Andreas; Honegger, Juergen; Carmona, Hans; Huppertz, Hans-Juergen; Pantazis, Georgios; Rona, Sabine; Bast, Thomas; Strobl, Karl; Steinhoff, Bernhard J; Korinthenberg, Rudolf; Rating, Dietz; Volk, Benedikt; Zentner, Josef

2004-11-01

The purpose of this study was to assess whether the histological subtype of focal cortical dysplasia and dual pathology affect surgical outcome in patients with medically intractable epilepsy due to focal cortical dysplasia (FCD). We retrospectively analysed the outcome of 67 patients from 2 to 66 years of age at follow-up periods of 6 to 48 months after epilepsy surgery. Histological subtypes were classified according to Palmini and included a few cases with mild histological abnormalities corresponding to the definition of mild malformations of cortical development. The seizure outcome was classified according to Engel and evaluated at the last follow-up visit as well as at follow-up periods of 12 and 24 months after surgery. The outcome in patients with FCD and additional hippocampal pathology (dual pathology) was analysed separately. Distribution of histological subtypes differed in temporal and extratemporal localization, with a significantly higher extratemporal prevalence of FCD type 2. There was a tendency towards better postsurgical outcome related to the last follow-up visit in patients with more subtle abnormalities classified as mild malformations of cortical development (mMCD) (63% Engel Ia), FCD type 1a (67% Engel Ia) and FCD type 1b (55% Engel Ia) compared with patients with FCD type 2a (43% Engel Ia) and FCD type 2b (Taylor type) (50% Engel Ia). Considering the outcome at follow-up periods over 12 and 24 months, complete seizure-freedom was achieved significantly more often in patients with FCD type 1 and mMCD than with FCD type 2, and seizure reduction by less than 75% (Engel IV) occurred in more patients with FCD type 2a compared with the other subgroups. This tendency was seen in the whole patient group and in the extratemporal subgroup. Patients with dual pathology almost always had temporal lobe epilepsy; the outcome in this patient group was generally favourable (66% complete seizure-freedom at the last follow-up visit). The outcome remained almost constant with longer periods of follow-up. We conclude that patients with FCD type 1 and mMCD had a better outcome compared with those with more severe forms of cortical dysplasia. A higher incidence of FCD type 1 in temporal localization did not allow the effects of histological subtype and localization to be separated. A subanalysis of extratemporal FCDs, however, revealed a similar tendency for a better outcome with FCD type 1, suggesting that the histological subtype itself seems to be at least a relevant cofactor influencing postsurgical outcome.

Individual social security accounts: issues in assessing administrative feasibility and costs.

PubMed

Olsen, K A; Salisbury, D L

1998-11-01

Whether to add individual accounts (IAs) to the Social Security system is a highly political issue. But almost lost in the debate so far have been any practical considerations about how to administer such accounts. Any discussion of whether to create individual accounts must also address the basic but critical questions of how they would work: Who would run them? What would they cost? Logistically, are they even possible? This EBRI Issue Brief provides an overview of the most salient administrative issues facing the current Social Security reform debate--issues that challenge proponents to carefully think through how their proposals could be implemented so as to achieve their policy goals. The options and difficulties in administering IAs raise concerns that cut across ideology. The object of this report is neither to dissuade the advocates nor support the critics of individual accounts. Rather, it is to bring practical considerations to a political debate that has largely ignored the pragmatic challenges of whether IAs would be too complex for participants to understand or too difficult for record keepers to administer. The major findings in this analysis include: Adding individual accounts to Social Security could be the largest undertaking in the history of the U.S. financial market, and no system to date has the capacity to administer such a system. The number of workers currently covered by Social Security--the largest single entitlement program in the nation--is at least four times higher than the combined number of all tax-favored employment-based retirement accounts in the United States, which are administered by hundreds of entities. Direct comparisons between employment-based retirement savings plans and Social Security reform are tenuous at best. Social Security covers workers and businesses that are disproportionately excluded from employment-based plans. Because of these differences, a system of individual Social Security accounts would be more difficult to administer than employment-based plans, and total administrative expenses would be larger relative to benefits. Credit-based systems such as the current Social Security program are less difficult to administer than cash-based systems, which must account for every dollar. Inherent in the "privatization" debate is generally the presumption that IA benefits would be based on cash contributions and investment returns. The current credit-based system tolerates small errors in wage reporting, because they rarely affect benefits. But every dollar counts in a cash-based IA system. To ensure that benefits are properly provided, an IA system would require more regulation, oversight, and error reconciliation than the current Social Security program. Social Security individual accounts cannot be administered like 401(k) plans without adding significant employer burdens--especially on small businesses. Under the current wage reporting and tax collection process, it would take at least 7-19 months for every dollar contributed to an individual's account to be sorted out from aggregate payments and credited to his or her IA. This 7-19 month "float period" could result in substantial benefit losses over time. Options for preventing such losses involve difficult trade-offs, such as increased government responsibility, increased complexity, greater employer burdens, and/or investment restrictions for beneficiaries. If legally considered personal property, the IAs of married participants could pose significant administrative challenges. Social Security today must obtain proof of marriage only at the time spousal benefits are claimed. But some IA proposals would require contributions to be split between spouses' individual accounts, requiring records on participants' marital status to be continuously update to ensure that contributions are correctly directed. Also, dealing with claims on individual account contributions in divorce cases could place IA record keepers in the middle o

Violent Mergers

NASA Astrophysics Data System (ADS)

Pakmor, Rüdiger

The progenitor systems and explosion scenarios of Type Ia supernovae (SNe Ia) are still heavily debated. The violent merger scenario is a recent addition to explosion scenarios for SNe Ia. Here, two white dwarfs (WDs) in a binary system approach each other owing to the emission of gravitational waves. The interaction between the two WDs preluding or during the merger creates a hotspot on the surface of the primary, more massive, WD that ignites a detonation. If the detonation is a carbon detonation, it completely burns the primary WD leading to a SN Ia. If instead the detonation is a helium detonation in the helium shell of a carbon-oxygen WD, it burns around the primary WD in its helium shell and sends a shock wave into its core that ignites a carbon detonation. Again the primary WD is fully burned. Synthetic observables for explosion models of SNe Ia in the violent merger scenario show good agreement with normal SNe Ia and the subclass of faint, slowly evolving 02es-like SNe Ia for different masses of the primary WD. The violent merger scenario can also explain the delay time distribution and brightness distribution of normal SNe Ia. This chapter discusses in detail the mechanism that leads to ignition in the violent merger scenario, summarizes the properties of explosions in the violent merger scenario and compares to observations. It ends with a summary of the main properties of the population of normal SNe Ia and discusses to which degree they can be explained in the violent merger scenario.

Islet cell autoantibodies in African patients with Type 1 and Type 2 diabetes in Dar es Salaam Tanzania: a cross sectional study

PubMed Central

Lutale, JJK; Thordarson, H; Holm, PI; Eide, GE; Vetvik, K

2007-01-01

Background The aim of the present study was to assess the occurrence of glutamic acid decarboxylase autoantibodies (GADA) and insulinoma antigen 2 autoantibodies (IA2A) among patients of African origin in Dar es Salaam, Tanzania and to compare the occurrence of autoimmune mediated Type 1 diabetes with findings previously reported from the same place and from other African diabetic populations. Methods Two hundred and forty five patients from the diabetic clinic at Muhimbili Hospital were recruited for a cross sectional study. Patients were clinically classified into groups with Type 1 (T1D) and Type 2 diabetes (T2D); there were 94 patients with T1D and 151 with T2D. Autoantibodies for GAD and IA2 were measured with an assay based on radioligand binding. Fasting and random blood glucose, HbA1c, and C-peptide levels were also determined. Results Of the patients with T1D, 28 (29.8%) were GADA positive and 20 (21.3%) were IA2A positive. The overall occurrence of any autoantibody was 42.6%. The GAD and IA2 autoantibodies were detected more frequently among patients with T1D than among patients with T2D (P < 0.001). A higher autoantibody prevalence was observed with combined GADA and IA2A measurements compared to individual autoantibody measurements; 40 (42.6%) patients with T1D versus 11 (7.3%) with T2D had at least one positive autoantibody titer. There was no correlation between duration of disease and detection of autoantibodies in patients with T1D. There was a strong association with family history of diabetes among the autoantibody positive versus autoantibody negative patients with T1D (p < 0.01). Conclusion The prevalence of GAD and IA2 autoantibodies among African patients with T1D in Dar es Salaam was the same as that reported previously for South Africa and Ethiopia. It was much higher than the prevalence of islet cell autoantibodies (ICA) reported from the same clinic about 15 years ago. For unknown reasons the prevalence of pancreatic related autoantibodies in this African population is lower than the prevalence found among Caucasian populations. PMID:17963519

The Infrared Hubble Diagram of Type Ia Supernovae

NASA Astrophysics Data System (ADS)

Krisciunas, Kevin

Photometry of Type Ia supernovae reveals that these objects are standardizable candles in optical passbands - the peak luminosities are related to the rate of decline after maximum light. In the near-infrared bands, there is essentially a characteristic brightness at maximum light for each photometric band. Thus, in the near-infrared they are better than standardizable candles; they are essentially standard candles. Their absolute magnitudes are known to ±0.15 magnitude or better. The infrared observations have the extra advantage that interstellar extinction by dust along the line of sight is a factor of 3-10 smaller than in the optical B- and V -bands. The size of any systematic errors in the infrared extinction corrections typically become smaller than the photometric errors of the observations. Thus, we can obtain distances to the hosts of Type Ia supernovae to ±8 % or better. This is particularly useful for extragalactic astronomy and precise measurements of the dark energy component of the universe.

Photometric Type Ia supernova surveys in narrow-band filters

NASA Astrophysics Data System (ADS)

Xavier, Henrique S.; Abramo, L. Raul; Sako, Masao; Benítez, Narciso; Calvão, Maurício O.; Ederoclite, Alessandro; Marín-Franch, Antonio; Molino, Alberto; Reis, Ribamar R. R.; Siffert, Beatriz B.; Sodré, Laerte.

2014-11-01

We study the characteristics of a narrow-band Type Ia supernova (SN) survey through simulations based on the upcoming Javalambre Physics of the accelerating Universe Astrophysical Survey. This unique survey has the capabilities of obtaining distances, redshifts and the SN type from a single experiment thereby circumventing the challenges faced by the resource-intensive spectroscopic follow-up observations. We analyse the flux measurements signal-to-noise ratio and bias, the SN typing performance, the ability to recover light-curve parameters given by the SALT2 model, the photometric redshift precision from Type Ia SN light curves and the effects of systematic errors on the data. We show that such a survey is not only feasible but may yield large Type Ia SN samples (up to 250 SNe at z < 0.5 per month of search) with low core-collapse contamination (˜1.5 per cent), good precision on the SALT2 parameters (average σ _{m_B}=0.063, σ _{x_1}=0.47 and σc = 0.040) and on the distance modulus (average σμ = 0.16, assuming an intrinsic scatter σint = 0.14), with identified systematic uncertainties σsys ≲ 0.10σstat. Moreover, the filters are narrow enough to detect most spectral features and obtain excellent photometric redshift precision of σz = 0.005, apart from ˜2 per cent of outliers. We also present a few strategies for optimizing the survey's outcome. Together with the detailed host galaxy information, narrow-band surveys can be very valuable for the study of SN rates, spectral feature relations, intrinsic colour variations and correlations between SN and host galaxy properties, all of which are important information for SN cosmological applications.

White Dwarf/M Dwarf Binaries as Single Degenerate Progenitors of Type Ia Supernovae

NASA Astrophysics Data System (ADS)

Wheeler, J. Craig

2012-10-01

Limits on the companions of white dwarfs in the single-degenerate scenario for the origin of Type Ia supernovae (SNe Ia) have gotten increasingly tight, yet igniting a nearly Chandrasekhar mass C/O white dwarf from a condition of near hydrostatic equilibrium provides compelling agreement with observed spectral evolution. The only type of non-degenerate stars that survive the tight limits, MV >~ 8.4 on the SN Ia in SNR 0509-67.5 and MV >~ 9.5 in the remnant of SN 1572, are M dwarfs. While M dwarfs are observed in cataclysmic variables, they have special properties that have not been considered in most work on the progenitors of SNe Ia: they have small but finite magnetic fields and they flare frequently. These properties are explored in the context of SN Ia progenitors. White dwarf/M dwarf pairs may be sufficiently plentiful to provide, in principle, an adequate rate of explosions even with slow orbital evolution due to magnetic braking or gravitational radiation. Even modest magnetic fields on the white dwarf and M dwarf will yield adequate torques to lock the two stars together, resulting in a slowly rotating white dwarf, with the magnetic poles pointing at one another in the orbital plane. The mass loss will be channeled by a "magnetic bottle" connecting the two stars, landing on a concentrated polar area on the white dwarf. This enhances the effective rate of accretion compared to spherical accretion. Luminosity from accretion and hydrogen burning on the surface of the white dwarf may induce self-excited mass transfer. The combined effects of self-excited mass loss, polar accretion, and magnetic inhibition of mixing of accretion layers give possible means to beat the "nova limit" and grow the white dwarf to the Chandrasekhar mass even at rather moderate mass accretion rates.

Mesoscale Numerical Simulations of the IAS Circulation

NASA Astrophysics Data System (ADS)

Mooers, C. N.; Ko, D.

2008-05-01

Real-time nowcasts and forecasts of the IAS circulation have been made for several years with mesoscale resolution using the Navy Coastal Ocean Model (NCOM) implemented for the IAS. It is commonly called IASNFS and is driven by the lower resolution Global NCOM on the open boundaries, synoptic atmospheric forcing obtained from the Navy Global Atmospheric Prediction System (NOGAPS), and assimilated satellite-derived sea surface height anomalies and sea surface temperature. Here, examples of the model output are demonstrated; e.g., Gulf of Mexico Loop Current eddy shedding events and the meandering Caribbean Current jet and associated eddies. Overall, IASNFS is ready for further analysis, application to a variety of studies, and downscaling to even higher resolution shelf models. Its output fields are available online through NOAA's National Coastal Data Development Center (NCDDC), located at the Stennis Space Center.

Illuminating a Dark Lens : A Type Ia Supernova Magnified by the Frontier Fields Galaxy Cluster Abell 2744

NASA Astrophysics Data System (ADS)

Rodney, Steven A.; Patel, Brandon; Scolnic, Daniel; Foley, Ryan J.; Molino, Alberto; Brammer, Gabriel; Jauzac, Mathilde; Bradač, Maruša; Broadhurst, Tom; Coe, Dan; Diego, Jose M.; Graur, Or; Hjorth, Jens; Hoag, Austin; Jha, Saurabh W.; Johnson, Traci L.; Kelly, Patrick; Lam, Daniel; McCully, Curtis; Medezinski, Elinor; Meneghetti, Massimo; Merten, Julian; Richard, Johan; Riess, Adam; Sharon, Keren; Strolger, Louis-Gregory; Treu, Tommaso; Wang, Xin; Williams, Liliya L. R.; Zitrin, Adi

2015-09-01

SN HFF14Tom is a Type Ia SN discovered at z=1.3457+/- 0.0001 behind the galaxy cluster Abell 2744 (z = 0.308). In a cosmology-independent analysis, we find that HFF14Tom is 0.77 ± 0.15 mag brighter than unlensed Type Ia SNe at similar redshift, implying a lensing magnification of {μ }{obs}=2.03+/- 0.29. This observed magnification provides a rare opportunity for a direct empirical test of galaxy cluster lens models. Here we test 17 lens models, 13 of which were generated before the SN magnification was known, qualifying as pure “blind tests.” The models are collectively fairly accurate: 8 of the models deliver median magnifications that are consistent with the measured μ to within 1σ. However, there is a subtle systematic bias: the significant disagreements all involve models overpredicting the magnification. We evaluate possible causes for this mild bias, and find no single physical or methodological explanation to account for it. We do find that model accuracy can be improved to some extent with stringent quality cuts on multiply imaged systems, such as requiring that a large fraction have spectroscopic redshifts. In addition to testing model accuracies as we have done here, Type Ia SN magnifications could also be used as inputs for future lens models of Abell 2744 and other clusters, providing valuable constraints in regions where traditional strong- and weak-lensing information is unavailable.

Discovery and Follow-up Observations of the Young Type Ia Supernova 2016coj

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, WeiKang; Filippenko, Alexei V.; Mauerhan, Jon

The Type Ia supernova (SN Ia) 2016coj in NGC 4125 (redshift z = 0.00452 ± 0.00006) was discovered by the Lick Observatory Supernova Search 4.9 days after the fitted first-light time (FFLT; 11.1 days before B-band maximum). Our first detection (prediscovery) is merely 0.6 ± 0.5 days after the FFLT, making SN 2016coj one of the earliest known detections of an SN Ia. A spectrum was taken only 3.7 hr after discovery (5.0 days after the FFLT) and classified as a normal SN Ia. In this study, we performed high-quality photometry, low- and high-resolution spectroscopy, and spectropolarimetry, finding that SNmore » 2016coj is a spectroscopically normal SN Ia, but the velocity of Si ii λ6355 around peak brightness (~12,600 kms -1) is a bit higher than that of typical normal SNe. The Si ii λ6355 velocity evolution can be well fit by a broken-power-law function for up to a month after the FFLT. SN 2016coj has a normal peak luminosity (M B≈ -18.9 ± 0.2 mag), and it reaches a B-band maximum ~16.0 days after the FFLT. We estimate there to be low host-galaxy extinction based on the absence of Na i D absorption lines in our low- and high-resolution spectra. Finally, the spectropolarimetric data exhibit weak polarization in the continuum, but the Si ii line polarization is quite strong (~0.9% ± 0.1%) at peak brightness.« less

Constraining Type Ia Supernova Progenitor Scenarios with Extremely Late-time Photometry of Supernova SN 2013aa

NASA Astrophysics Data System (ADS)

Jacobson-Galán, Wynn V.; Dimitriadis, Georgios; Foley, Ryan J.; Kilpatrick, Charles D.

2018-04-01

We present Hubble Space Telescope observations and photometric measurements of the Type Ia supernova (SN Ia) SN 2013aa 1500 days after explosion. At this epoch, the luminosity is primarily dictated by the amounts of radioactive {}57{{Co}} and {}55{{Fe}}, while at earlier epochs, the luminosity depends on the amount of radioactive {}56{{Co}}. The ratio of odd-numbered to even-numbered isotopes depends significantly on the density of the progenitor white dwarf (WD) during the SN explosion, which, in turn, depends on the details of the progenitor system at the time of ignition. From a comprehensive analysis of the entire light curve of SN 2013aa, we measure a M({}57{{Co}})/M({}56{{Co}}) ratio of {0.02}-0.02+0.01, which indicates a relatively low central density for the progenitor WD at the time of explosion, consistent with DD progenitor channels. We estimate M({}56{{Ni}}) = 0.732 +/- 0.151 {M}ȯ , and place an upper limit on the abundance of {}55{{Fe}}. A recent study reported a possible correlation between M({}57{{Co}})/M({}56{{Co}}) and stretch for four SNe Ia. SN 2013aa, however, does not fit this trend, indicating either SN 2013aa is an extreme outlier or the correlation does not hold up with a larger sample. The M({}57{{Co}})/M({}56{{Co}}) measured for the expanded sample of SNe Ia with photometry at extremely late times has a much larger range than that of explosion models, perhaps limiting conclusions about SN Ia progenitors drawn from extremely late-time photometry.

Discovery and Follow-up Observations of the Young Type Ia Supernova 2016coj

NASA Astrophysics Data System (ADS)

Zheng, WeiKang; Filippenko, Alexei V.; Mauerhan, Jon; Graham, Melissa L.; Yuk, Heechan; Hosseinzadeh, Griffin; Silverman, Jeffrey M.; Rui, Liming; Arbour, Ron; Foley, Ryan J.; Abolfathi, Bela; Abramson, Louis E.; Arcavi, Iair; Barth, Aaron J.; Bennert, Vardha N.; Brandel, Andrew P.; Cooper, Michael C.; Cosens, Maren; Fillingham, Sean P.; Fulton, Benjamin J.; Halevi, Goni; Howell, D. Andrew; Hsyu, Tiffany; Kelly, Patrick L.; Kumar, Sahana; Li, Linyi; Li, Wenxiong; Malkan, Matthew A.; Manzano-King, Christina; McCully, Curtis; Nugent, Peter E.; Pan, Yen-Chen; Pei, Liuyi; Scott, Bryan; Sexton, Remington Oliver; Shivvers, Isaac; Stahl, Benjamin; Treu, Tommaso; Valenti, Stefano; Vogler, H. Alexander; Walsh, Jonelle L.; Wang, Xiaofeng

2017-05-01

The Type Ia supernova (SN Ia) 2016coj in NGC 4125 (redshift z = 0.00452 ± 0.00006) was discovered by the Lick Observatory Supernova Search 4.9 days after the fitted first-light time (FFLT; 11.1 days before B-band maximum). Our first detection (prediscovery) is merely 0.6 ± 0.5 days after the FFLT, making SN 2016coj one of the earliest known detections of an SN Ia. A spectrum was taken only 3.7 hr after discovery (5.0 days after the FFLT) and classified as a normal SN Ia. We performed high-quality photometry, low- and high-resolution spectroscopy, and spectropolarimetry, finding that SN 2016coj is a spectroscopically normal SN Ia, but the velocity of Si II λ6355 around peak brightness (˜12,600 {km} {{{s}}}-1) is a bit higher than that of typical normal SNe. The Si II λ6355 velocity evolution can be well fit by a broken-power-law function for up to a month after the FFLT. SN 2016coj has a normal peak luminosity ({M}B≈ -18.9+/- 0.2 mag), and it reaches a B-band maximum ˜16.0 days after the FFLT. We estimate there to be low host-galaxy extinction based on the absence of Na I D absorption lines in our low- and high-resolution spectra. The spectropolarimetric data exhibit weak polarization in the continuum, but the Si II line polarization is quite strong (˜0.9% ± 0.1%) at peak brightness.

Cosmic Explosions in Three Dimensions

NASA Astrophysics Data System (ADS)

Höflich, Peter; Kumar, Pawan; Wheeler, J. Craig

2011-08-01

Introduction: 3-D Explosions: a meditation on rotation (and magnetic fields) J. C. Wheeler; Part I. Supernovae: Observations Today: 1. Supernova explosions: lessons from spectropolarimetry L. Wang; 2. Spectropolarimetric observations of Supernovae A. Filippenko and D. C. Leonard; 3. Observed and physical properties of type II plateau supernovae M. Hamuy; 4. SN1997B and the different types of Type Ic Supernovae A. Clocchiatti, B. Leibundgut, J. Spyromilio, S. Benetti, E. Cappelaro, M. Turatto and M. Phillips; 5. Near-infrared spectroscopy of stripped-envelope Supernovae C. L. Gerardy, R. A. Fesen, G. H. Marion, P. Hoeflich and J. C. Wheeler; 6. Morphology of Supernovae remnants R. Fesen; 7. The evolution of Supernova remnants in the winds of massive stars V. Dwarkadas; 8. Types for the galactic Supernovae B. E. Schaefer; Part II. Theory of Thermonuclear Supernovae: 9. Semi-steady burning evolutionary sequences for CAL 83 and CAL 87: supersoft X-ray binaries are Supernovae Ia progenitors S. Starrfield, F. X. Timmes, W. R. Hix, E. M. Sion, W. M. Sparks and S. Dwyer; 10. Type Ia Supernovae progenitors: effects of the spin-up of the white dwarfs S.-C. Yoon and N. Langer; 11. Terrestrial combustion: feedback to the stars E. S. Oran; 12. Non-spherical delayed detonations E. Livne; 13. Numerical simulations of Type Ia Supernovae: deflagrations and detonations V. N. Gamezo, A. M. Khokhlov and E. S. Oran; 14. Type Ia Supernovae: spectroscopic surprises D. Branch; 15. Aspherity effects in Supernovae P. Hoeflich, C. Gerardy and R. Quimby; 16. Broad light curve SneIa: asphericity or something else? A. Howell and P. Nugent; 17. Synthetic spectrum methods for 3-D SN models R. Thomas; 18. A hole in Ia' spectroscopic and polarimetric signatures of SN Ia asymmetry due to a companion star D. Kasen; 19. Hunting for the signatures of 3-D explosions with 1-D synthetic spectra E. Lentz, E. Baron and P. H. Hauschildt; 20. On the variation of the peak luminosity of Type Ia J. W. Truran, E. X. Timmes and E. F. Brown; Part III. Theory of Core Collapse Supernovae: 21. Rotation of core collapse progenitors: single and binary stars N. Langer; 22. Large scale convection and the convective Supernova mechanism S. Colgate and M. E. Herant; 23. Topics in core-collapse Supernova A. Burrows, C. D. Ott and C. Meakin; 24. MHD Supernova jets: the missing link D. Meier and M. Nakamura; 25. Effects of super strong magnetic fields in core collapse Supernovae I. S. Akiyama; 26. Non radial instability of stalled accretion shocks advective-acoustic cycle T. Foglizzo and P. Galletti; 27. Asymmetry effects in Hypernovae K. Maeda, K. Nomoto, J. Deng and P.A. Mazzali; 28. Turbulent MHD jet collimation and thermal driving P. T. Williams; Part IV. Magnetars, N-Stars, Pulsars: 29. Supernova remnants and pulsar wind nebulae R. Chevalier; 30. X-Ray signatures of Supernovae D. Swartz; 31. Asymmetric Supernovae and Neutron Star Kicks D. Lai and D. Q. Lamb; 32. Triggers of magnetar outbursts R. Duncan; 33. Turbulent MHD Jet Collimation and Thermal Driving P. Williams; 34. The interplay between nuclear electron capture and fluid dynamics in core collapse Supernovae W. R. Hix, O. E. B. Messer and A. Mezzacappa; Part V. Gamma-Ray Bursts: 35. GRB 021004 and Gamma-ray burst distances B. E. Schaefer; 36. Gamma-ray bursts as a laboratory for the study of Type Ic Supernovae D. Q. Lamb, T. Q. Donaghy and C. Graziani; 37. The diversity of cosmic explosions: Gamma-ray bursts and Type Ib/c Supernovae E. Berger; 38. A GRB simulation using 3D relativistic hydrodynamics J. Cannizo, N. Gehrels and E. T. Vishniac; 39. The first direct link in the Supernova/GRB connection: GRB 030329 and SN 2003dh T. Matheson; Part VI. Summary: 40. Three-dimensional explosions C. Wheeler.

Comparing multi-criteria decision analysis and integrated assessment to support long-term water supply planning

PubMed Central

Maurer, Max; Lienert, Judit

2017-01-01

We compare the use of multi-criteria decision analysis (MCDA)–or more precisely, models used in multi-attribute value theory (MAVT)–to integrated assessment (IA) models for supporting long-term water supply planning in a small town case study in Switzerland. They are used to evaluate thirteen system scale water supply alternatives in four future scenarios regarding forty-four objectives, covering technical, social, environmental, and economic aspects. The alternatives encompass both conventional and unconventional solutions and differ regarding technical, spatial and organizational characteristics. This paper focuses on the impact assessment and final evaluation step of the structured MCDA decision support process. We analyze the performance of the alternatives for ten stakeholders. We demonstrate the implications of model assumptions by comparing two IA and three MAVT evaluation model layouts of different complexity. For this comparison, we focus on the validity (ranking stability), desirability (value), and distinguishability (value range) of the alternatives given the five model layouts. These layouts exclude or include stakeholder preferences and uncertainties. Even though all five led us to identify the same best alternatives, they did not produce identical rankings. We found that the MAVT-type models provide higher distinguishability and a more robust basis for discussion than the IA-type models. The needed complexity of the model, however, should be determined based on the intended use of the model within the decision support process. The best-performing alternatives had consistently strong performance for all stakeholders and future scenarios, whereas the current water supply system was outperformed in all evaluation layouts. The best-performing alternatives comprise proactive pipe rehabilitation, adapted firefighting provisions, and decentralized water storage and/or treatment. We present recommendations for possible ways of improving water supply planning in the case study and beyond. PMID:28481881

In Vivo Zinc Finger Nuclease-mediated Targeted Integration of a Glucose-6-phosphatase Transgene Promotes Survival in Mice With Glycogen Storage Disease Type IA

PubMed Central

Landau, Dustin J; Brooks, Elizabeth Drake; Perez-Pinera, Pablo; Amarasekara, Hiruni; Mefferd, Adam; Li, Songtao; Bird, Andrew; Gersbach, Charles A; Koeberl, Dwight D

2016-01-01

Glycogen storage disease type Ia (GSD Ia) is caused by glucose-6-phosphatase (G6Pase) deficiency in association with severe, life-threatening hypoglycemia that necessitates lifelong dietary therapy. Here we show that use of a zinc-finger nuclease (ZFN) targeted to the ROSA26 safe harbor locus and a ROSA26-targeting vector containing a G6PC donor transgene, both delivered with adeno-associated virus (AAV) vectors, markedly improved survival of G6Pase knockout (G6Pase-KO) mice compared with mice receiving the donor vector alone (P < 0.04). Furthermore, transgene integration has been confirmed by sequencing in the majority of the mice treated with both vectors. Targeted alleles were 4.6-fold more common in livers of mice with GSD Ia, as compared with normal littermates, at 8 months following vector administration (P < 0.02). This suggests a selective advantage for vector-transduced hepatocytes following ZFN-mediated integration of the G6Pase vector. A short-term experiment also showed that 3-month-old mice receiving the ZFN had significantly-improved biochemical correction, in comparison with mice that received the donor vector alone. These data suggest that the use of ZFNs to drive integration of G6Pase at a safe harbor locus might improve vector persistence and efficacy, and lower mortality in GSD Ia. PMID:26865405

The cosmic transparency measured with Type Ia supernovae: implications for intergalactic dust

NASA Astrophysics Data System (ADS)

Goobar, Ariel; Dhawan, Suhail; Scolnic, Daniel

2018-04-01

Observations of high-redshift Type Ia supernovae (SNe Ia) are used to study the cosmic transparency at optical wavelengths. Assuming a flat ΛCDM cosmological model based on BAO and CMB results, redshift dependent deviations of SN Ia distances are used to constrain mechanisms that would dim light. The analysis is based on the most recent Pantheon SN compilation, for which there is a 0.03± 0.01 {(stat)} mag discrepancy in the distant supernova distance moduli relative to the ΛCDM model anchored by supernovae at z < 0.05. While there are known systematic uncertainties that combined could explain the observed offset, here we entertain the possibility that the discrepancy may instead be explained by scattering of supernova light in the intergalactic medium (IGM). We focus on two effects: Compton scattering by free electrons and extinction by dust in the IGM. We find that if the discrepancy is due entirely to dimming by dust, the measurements can be modeled with a cosmic dust density Ω _IGM^dust = 8 \\cdot 10^{-5} (1+z)^{-1}, corresponding to an average attenuation of 2 . 10-5 mag Mpc-1 in V-band. Forthcoming SN Ia studies may provide a definitive measurement of the IGM dust properties, while still providing an unbiased estimate of cosmological parameters by introducing additional parameters in the global fits to the observations.

Against the Wind: Radio Light Curves of Type IA Supernovae Interacting with Low-Density Circumstellar Shells

DOE PAGES

Harris, Chelsea E.; Nugent, Peter E.; Kasen, Daniel N.

2016-05-26

For decades a wide variety of observations spanning the radio through optical and on to the X-ray have attempted to uncover signs of type Ia supernovae (SNe Ia) interacting with a circumstellar medium (CSM). The goal of these studies is to constrain the nature of the hypothesized SN Ia mass-donor companion. A continuous CSM is typically assumed when interpreting observations of interaction. However, while such models have been successfully applied to core-collapse SNe, the assumption of continuity may not be accurate for SNe Ia, because shells of CSM could be formed by pre-supernova eruptions (novae). In this work, we modelmore » the interaction of SNe with a spherical, low-density, finite-extent CSM and create a suite of synthetic radio synchrotron light curves. We find that CSM shells produce sharply peaked light curves. We also identify a fiducial set of models that obey a common evolution and can be used to generate radio light curves for an interaction with an arbitrary shell. The relations obeyed by the fiducial models can be used to deduce CSM properties from radio observations; we demonstrate this by applying them to the nondetections of SN 2011fe and SN 2014J. Finally, we explore a multiple shell CSM configuration and describe its more complicated dynamics and the resultant radio light curves.« less

AGAINST THE WIND: RADIO LIGHT CURVES OF TYPE IA SUPERNOVAE INTERACTING WITH LOW-DENSITY CIRCUMSTELLAR SHELLS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harris, Chelsea E.; Nugent, Peter E.; Kasen, Daniel N., E-mail: chelseaharris@berkeley.edu

2016-06-01

For decades a wide variety of observations spanning the radio through optical and on to the X-ray have attempted to uncover signs of type Ia supernovae (SNe Ia) interacting with a circumstellar medium (CSM). The goal of these studies is to constrain the nature of the hypothesized SN Ia mass-donor companion. A continuous CSM is typically assumed when interpreting observations of interaction. However, while such models have been successfully applied to core-collapse SNe, the assumption of continuity may not be accurate for SNe Ia, because shells of CSM could be formed by pre-supernova eruptions (novae). In this work, we modelmore » the interaction of SNe with a spherical, low-density, finite-extent CSM and create a suite of synthetic radio synchrotron light curves. We find that CSM shells produce sharply peaked light curves. We also identify a fiducial set of models that obey a common evolution and can be used to generate radio light curves for an interaction with an arbitrary shell. The relations obeyed by the fiducial models can be used to deduce CSM properties from radio observations; we demonstrate this by applying them to the nondetections of SN 2011fe and SN 2014J. Finally, we explore a multiple shell CSM configuration and describe its more complicated dynamics and the resultant radio light curves.« less

Growth hormone-releasing hormone resistance in pseudohypoparathyroidism type ia: new evidence for imprinting of the Gs alpha gene.

PubMed

Mantovani, Giovanna; Maghnie, Mohamad; Weber, Giovanna; De Menis, Ernesto; Brunelli, Valeria; Cappa, Marco; Loli, Paola; Beck-Peccoz, Paolo; Spada, Anna

2003-09-01

Heterozygous inactivating mutations in the Gs alpha gene cause Albright's hereditary osteodystrophy. Consistent with the observation that only maternally inherited mutations lead to resistance to hormone action [pseudohypoparathyroidism type Ia (PHP Ia)], recent studies provided evidence for a predominant maternal origin of Gs alpha transcripts in endocrine organs, such as thyroid, gonad, and pituitary. The aim of this study was to investigate the presence of pituitary resistance to hypothalamic hormones acting via Gs alpha-coupled receptors in patients with PHP Ia. Six of nine patients showed an impaired GH responsiveness to GHRH plus arginine, consistent with a complete GH deficiency (GH peak from 2.6-8.6 microg/liter, normal > 16.5), and partial (GH peak 13.9 and 13.6 microg/liter) and normal responses were found in two and one patient, respectively. Accordingly, IGF-I levels were below and in the low-normal range in seven and two patients. All patients had a normal cortisol response to 1 microg ACTH test, suggesting a normal corticotroph function that was confirmed by a normal ACTH and cortisol response to CRH test in three patients. In conclusion, we report that in addition to PTH and TSH resistance, patients with PHP Ia display variable degrees of GHRH resistance, consistent with Gs alpha imprinting in human pituitary.

Early Radio and X-Ray Observations of the Youngest Nearby Type Ia Supernova PTF 11kly (SN 2011fe)

NASA Technical Reports Server (NTRS)

Horesh, Assaf; Kulkarni, S. R.; Fox, Derek B.; Carpenter, John; Kasliwal, Mansi M.; Ofek, Eran O.; Quimby, Robert; Gal-Yam, Avishay; Cenko, S. Bradley; deBruyn, A. G.;

The cosmic transparency measured with Type Ia supernovae: implications for intergalactic dust

NASA Astrophysics Data System (ADS)

Goobar, Ariel; Dhawan, Suhail; Scolnic, Daniel

2018-06-01

Observations of high-redshift Type Ia supernovae (SNe Ia) are used to study the cosmic transparency at optical wavelengths. Assuming a flat Λ cold dark matter (ΛCDM) cosmological model based on baryon acoustic oscillations and cosmic microwave background measurements, redshift dependent deviations of SN Ia distances are used to constrain mechanisms that would dim light. The analysis is based on the most recent Pantheon SN compilation, for which there is a 0.03 ± 0.01 {({stat})} mag discrepancy in the distant supernova distance moduli relative to the ΛCDM model anchored by supernovae at z < 0.05. While there are known systematic uncertainties that combined could explain the observed offset, here we entertain the possibility that the discrepancy may instead be explained by scattering of supernova light in the intergalactic medium (IGM). We focus on two effects: Compton scattering by free electrons and extinction by dust in the IGM. We find that if the discrepancy is entirely due to dimming by dust, the measurements can be modelled with a cosmic dust density Ω _IGM^dust = 8 × 10^{-5} (1+z)^{-1}, corresponding to an average attenuation of 2 × 10-5 mag Mpc-1 in V band. Forthcoming SN Ia studies may provide a definitive measurement of the IGM dust properties, while still providing an unbiased estimate of cosmological parameters by introducing additional parameters in the global fits to the observations.

Morphologic classification of the right auricule on 256-slice computed tomography.

PubMed

Li, Cai-Ying; Gao, Bu-Lang; Pan, Tong; Xiang, Cheng; Liu, Xiao-Wei; Yang, Hai-Qing; Yi, Lan-Ying; Liao, Qi-Bin

2017-06-01

To investigate the shape of right auricule on 256-slice computed tomography (CT). Five hundred people (250 men, age range 16-84 years) who had cardiac multidetector CT angiography were recruited in this study. All patients had normal sinus rhythm with normal blood pressure (<140/90 mmHg for systolic/diastolic pressure). The morphology of the right auricule was studied and compared after reconstruction of the raw images. All patients successfully had cardiac CT angiography (100%), and the right auricule morphology was divided into five types and nine subtypes, including Type I of triangular shape (Ia and Ib), Type II of M shape (IIa and IIb), Type III of L shape (IIIa and IIIb), Type IV of reverse L shape (IVa and IVb), and Type V of balanced shape. The most common type of right auricule is Type IV (28.4%) followed by Type II (24.0%), whereas the least common is Type V (11.0%). Type Ia was present significantly (P < 0.0001) more frequently in females than in males, whereas Type IIa significantly (P = 0.042) more frequently in males than females. No other significant (P > 0.05) sex difference existed in the constitution ratio of the types. The normal angle was greater in Type Ib than in Ia. The greater the normal angle in Type I, the greater the deviation of the right auricule tip towards the left. A good understanding of the right auricule anatomical morphology can better guide atrial pacing, radiofrequency ablation and other surgical procedures while preventing possible intra-procedural complications.

CHRONIC EXPOSURE TO ARSENITE IN DRINKING WATER IMPAIRS GLUCOSE TOLERANCE IN C57BL/6 MICE

EPA Science Inventory

Chronic exposures to inorganic arsenic (iAs) have been associated with increased prevalence of type 2 diabetes mellitus. This study examines in vivo diabetogenic effects of iAs in an animal model. Here, weanling male C57BL/6 mice received deionized water containing iAs(III) (25 ...

VizieR Online Data Catalog: Absolute UV magnitudes of type Ia SNe (Brown+, 2010)

NASA Astrophysics Data System (ADS)

Brown, P. J.; Roming, P. W. A.; Milne, P.; Bufano, F.; Ciardullo, R.; Elias-Rosa, N.; Filippenko, A. V.; Foley, R. J.; Gehrels, N.; Gronwall, C.; Hicken, M.; Holland, S. T.; Hoversten, E. A.; Immler, S.; Kirshner, R. P.; Li, W.; Mazzali, P.; Phillips, M. M.; Pritchard, T.; Still, M.; Turatto, M.; vanden Berk, D.

2012-07-01

This study includes the 14 Swift/UVOT SNe Ia from Brown et al. (2009, Cat. J/AJ/137/4517) and Milne et al. (2010ApJ...721.1627M) with low extinction (E(B-V)<0.5mag) and well-sampled light curves in at least one UV filter. (7 data files).

Characteristics of Social Network Gamers: Results of an Online Survey.

PubMed

Geisel, Olga; Panneck, Patricia; Stickel, Anna; Schneider, Michael; Müller, Christian A

2015-01-01

Current research on Internet addiction (IA) reported moderate to high prevalence rates of IA and comorbid psychiatric symptoms in users of social networking sites (SNS) and online role-playing games. The aim of this study was to characterize adult users of an Internet multiplayer strategy game within a SNS. Therefore, we conducted an exploratory study using an online survey to assess sociodemographic variables, psychopathology, and the rate of IA in a sample of adult social network gamers by Young's Internet Addiction Test (IAT), the Toronto Alexithymia Scale (TAS-26), the Beck Depression Inventory-II (BDI-II), the Symptom Checklist-90-R (SCL-90-R), and the WHO Quality of Life-BREF (WHOQOL-BREF). All participants were listed gamers of "Combat Zone" in the SNS "Facebook." In this sample, 16.2% of the participants were categorized as subjects with IA and 19.5% fulfilled the criteria for alexithymia. Comparing study participants with and without IA, the IA group had significantly more subjects with alexithymia, reported more depressive symptoms, and showed poorer quality of life. These findings suggest that social network gaming might also be associated with maladaptive patterns of Internet use. Furthermore, a relationship between IA, alexithymia, and depressive symptoms was found that needs to be elucidated by future studies.

Comparison of idiopathic (isolated) aortitis and giant cell arteritis-related aortitis. A French retrospective multicenter study of 117 patients.

PubMed

Espitia, Olivier; Samson, Maxime; Le Gallou, Thomas; Connault, Jérôme; Landron, Cedric; Lavigne, Christian; Belizna, Cristina; Magnant, Julie; de Moreuil, Claire; Roblot, Pascal; Maillot, François; Diot, Elisabeth; Jégo, Patrick; Durant, Cécile; Masseau, A; Brisseau, Jean-Marie; Pottier, Pierre; Espitia-Thibault, Alexandra; Santos, Anabele Dos; Perrin, François; Artifoni, Mathieu; Néel, Antoine; Graveleau, Julie; Moreau, Philippe; Maisonneuve, Hervé; Fau, Georges; Serfaty, Jean-Michel; Hamidou, Mohamed; Agard, Christian

2016-06-01

The aim of the study was to compare clinical/imaging findings and outcome in patients with idiopathic (isolated aortitis, IA) and with giant cell arteritis (GCA)-related aortitis. Patients from 11 French internal medicine departments were retrospectively included. Aortitis was defined by aortic wall thickening >2mm and/or an aortic aneurysm on CT-scan, associated to inflammatory syndrome. Patients with GCA had at least 3 ACR criteria. Aortic events (aneurysm, dissection, aortic surgeries) were reported, and free of aortic events-survival were compared. Among 191 patients with non-infectious aortitis, 73 with GCA and 44 with IA were included. Patients with IA were younger (65 vs 70 years, p=0.003) and comprised more past/current smokers (43 vs 15%, p=0.0007). Aortic aneurisms were more frequent (38% vs 20%, p=0.03), and aortic wall thickening was more pronounced in IA. During follow-up (median=34 months), subsequent development of aortic aneurysm was significantly lower in GCA when compared to IA (p=0.009). GCA patients required significantly less aortic surgery during follow-up than IA patients (p=0.02). Mean age, sex ratio, inflammatory parameters, and free of aortic aneurism survival were equivalent in patients with IA ≥ 60 years when compared to patients with GCA-related aortitis. IA is more severe than aortitis related to GCA, with higher proportions of aortic aneurism at diagnosis and during follow-up. IA is a heterogeneous disease and its prognosis is worse in younger patients <60 years. Most patients with IA ≥ 60 years share many features with GCA-related aortitis. Copyright © 2016 Elsevier B.V. All rights reserved.

Arsenic speciation analysis of urine samples from individuals living in an arsenic-contaminated area in Bangladesh.

PubMed

Hata, Akihisa; Yamanaka, Kenzo; Habib, Mohamed Ahsan; Endo, Yoko; Fujitani, Noboru; Endo, Ginji

2012-05-01

Chronic inorganic arsenic (iAs) exposure currently affects tens of millions of people worldwide. To accurately determine the proportion of urinary arsenic metabolites in residents continuously exposed to iAs, we performed arsenic speciation analysis of the urine of these individuals and determined whether a correlation exists between the concentration of iAs in drinking water and the urinary arsenic species content. The subjects were 165 married couples who had lived in the Pabna District in Bangladesh for more than 5 years. Arsenic species were measured using high-performance liquid chromatography and inductively coupled plasma mass spectrometry. The median iAs concentration in drinking water was 55 μgAs/L (range <0.5-332 μgAs/L). Speciation analysis revealed the presence of arsenite, arsenate, monomethylarsonic acid (MMA), and dimethylarsinic acid in urine samples with medians (range) of 16.8 (7.7-32.3), 1.8 (<0.5-3.3), 13.7 (5.6-25.0), and 88.6 μgAs/L (47.9-153.4 μgAs/L), respectively. No arsenobetaine or arsenocholine was detected. The concentrations of the 4 urinary arsenic species were significantly and linearly related to each other. The urinary concentrations of total arsenic and each species were significantly correlated with the iAs concentration of drinking water. All urinary arsenic species are well correlated with each other and with iAs in drinking water. The most significant linear relationship existed between the iAs concentration in drinking water and urinary iAs + MMA concentration. From these results, combined with the effects of seafood ingestion, the best biomarker of iAs exposure is urinary iAs + MMA concentration.

VizieR Online Data Catalog: Berkeley supernova Ia program. II. (Silverman+, 2012)

NASA Astrophysics Data System (ADS)

Silverman, J. M.; Kong, J. J.; Filippenko, A. V.

2013-08-01

In this second paper in a series, we present measurements of spectral features of 432 low-redshift (z<0.1) optical spectra of 261 Type Ia supernovae (SNe Ia) within 20d of maximum brightness. The data were obtained from 1989 to the end of 2008 as part of the Berkeley Supernova Ia Program (BSNIP) and are presented in BSNIP I by Silverman et al. (J/MNRAS/425/1789). We describe in detail our method of automated, robust spectral feature definition and measurement which expands upon similar previous studies. Using this procedure, we attempt to measure expansion velocities, pseudo-equivalent widths (pEWs), spectral feature depths and fluxes at the centre and endpoints of each of nine major spectral feature complexes. (10 data files).

Using Line Profiles to Test the Fraternity of Type Ia Supernovae at High and Low Redshifts

NASA Astrophysics Data System (ADS)

Blondin, Stéphane; Dessart, Luc; Leibundgut, Bruno; Branch, David; Höflich, Peter; Tonry, John L.; Matheson, Thomas; Foley, Ryan J.; Chornock, Ryan; Filippenko, Alexei V.; Sollerman, Jesper; Spyromilio, Jason; Kirshner, Robert P.; Wood-Vasey, W. Michael; Clocchiatti, Alejandro; Aguilera, Claudio; Barris, Brian; Becker, Andrew C.; Challis, Peter; Covarrubias, Ricardo; Davis, Tamara M.; Garnavich, Peter; Hicken, Malcolm; Jha, Saurabh; Krisciunas, Kevin; Li, Weidong; Miceli, Anthony; Miknaitis, Gajus; Pignata, Giuliano; Prieto, Jose Luis; Rest, Armin; Riess, Adam G.; Salvo, Maria Elena; Schmidt, Brian P.; Smith, R. Chris; Stubbs, Christopher W.; Suntzeff, Nicholas B.

2006-03-01

Using archival data of low-redshift (z<0.01 Center for Astrophysics and SUSPECT databases) Type Ia supernovae (SNe Ia) and recent observations of high-redshift (0.161.7] SNe Ia, which are also subluminous. In addition, we give the first direct evidence in two high-z SN Ia spectra of a double-absorption feature in Ca II λ3945, an event also observed, although infrequently, in low-redshift SN Ia spectra (6 out of 22 SNe Ia in our local sample). Moreover, echoing the recent studies of Dessart & Hillier in the context of Type II supernovae (SNe II), we see similar P Cygni line profiles in our large sample of SN Ia spectra. First, the magnitude of the velocity location at maximum profile absorption may underestimate that at the continuum photosphere, as observed, for example, in the optically thinner line S II λ5640. Second, we report for the first time the unambiguous and systematic intrinsic blueshift of peak emission of optical P Cygni line profiles in SN Ia spectra, by as much as 8000 km s-1. All the high-z SNe Ia analyzed in this paper were discovered and followed up by the ESSENCE collaboration and are now publicly available. Based in part on observations obtained at the Cerro Tololo Inter-American Observatory, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under cooperative agreement with the National Science Foundation (NSF); the European Southern Observatory, Chile (ESO program 170.A-0519) the Gemini Observatory, which is operated by AURA under a cooperative agreement with the NSF on behalf of the Gemini partnership (the NSF [United States], the Particle Physics and Astronomy Research Council [United Kingdom], the National Research Council [Canada], CONICYT [Chile], the Australian Research Council [Australia], CNPq [Brazil], and CONICET [Argentina]) (programs GN-2002B-Q-14, GN-2003B-Q-11, and GS-2003B-Q-11) the Magellan Telescopes at Las Campanas Observatory; the MMT Observatory, a joint facility of the Smithsonian Institution and the University of Arizona; and the F. L. Whipple Observatory, which is operated by the Smithsonian Astrophysical Observatory. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

Knockout of arsenic (+3 oxidation state) methyltransferase is associated with adverse metabolic phenotype in mice: the role of sex and arsenic exposure.

PubMed

Douillet, Christelle; Huang, Madelyn C; Saunders, R Jesse; Dover, Ellen N; Zhang, Chongben; Stýblo, Miroslav

2017-07-01

Susceptibility to toxic effects of inorganic arsenic (iAs) depends, in part, on efficiency of iAs methylation by arsenic (+3 oxidation state) methyltransferase (AS3MT). As3mt-knockout (KO) mice that cannot efficiently methylate iAs represent an ideal model to study the association between iAs metabolism and adverse effects of iAs exposure, including effects on metabolic phenotype. The present study compared measures of glucose metabolism, insulin resistance and obesity in male and female wild-type (WT) and As3mt-KO mice during a 24-week exposure to iAs in drinking water (0.1 or 1 mg As/L) and in control WT and As3mt-KO mice drinking deionized water. Results show that effects of iAs exposure on fasting blood glucose (FBG) and glucose tolerance in either WT or KO mice were relatively minor and varied during the exposure. The major effects were associated with As3mt KO. Both male and female control KO mice had higher body mass with higher percentage of fat than their respective WT controls. However, only male KO mice were insulin resistant as indicated by high FBG, and high plasma insulin at fasting state and 15 min after glucose challenge. Exposure to iAs increased fat mass and insulin resistance in both male and female KO mice, but had no significant effects on body composition or insulin resistance in WT mice. These data suggest that As3mt KO is associated with an adverse metabolic phenotype that is characterized by obesity and insulin resistance, and that the extent of the impairment depends on sex and exposure to iAs, including exposure to iAs from mouse diet.

Environment-sensitive fluorophores with benzothiadiazole and benzoselenadiazole structures as candidate components of a fluorescent polymeric thermometer.

PubMed

Uchiyama, Seiichi; Kimura, Kohki; Gota, Chie; Okabe, Kohki; Kawamoto, Kyoko; Inada, Noriko; Yoshihara, Toshitada; Tobita, Seiji

2012-07-27

An environment-sensitive fluorophore can change its maximum emission wavelength (λ(em)), fluorescence quantum yield (Φ(f)), and fluorescence lifetime in response to the surrounding environment. We have developed two new intramolecular charge-transfer-type environment-sensitive fluorophores, DBThD-IA and DBSeD-IA, in which the oxygen atom of a well-established 2,1,3-benzoxadiazole environment-sensitive fluorophore, DBD-IA, has been replaced by a sulfur and selenium atom, respectively. DBThD-IA is highly fluorescent in n-hexane (Φ(f) =0.81, λ(em) =537 nm) with excitation at 449 nm, but is almost nonfluorescent in water (Φ(f) =0.037, λ(em) =616 nm), similarly to DBD-IA (Φ(f) =0.91, λ(em) =520 nm in n-hexane; Φ(f) =0.027, λ(em) =616 nm in water). A similar variation in fluorescence properties was also observed for DBSeD-IA (Φ(f) =0.24, λ(em) =591 nm in n-hexane; Φ(f) =0.0046, λ(em) =672 nm in water). An intensive study of the solvent effects on the fluorescence properties of these fluorophores revealed that both the polarity of the environment and hydrogen bonding with solvent molecules accelerate the nonradiative relaxation of the excited fluorophores. Time-resolved optoacoustic and phosphorescence measurements clarified that both intersystem crossing and internal conversion are involved in the nonradiative relaxation processes of DBThD-IA and DBSeD-IA. In addition, DBThD-IA exhibits a 10-fold higher photostability in aqueous solution than the original fluorophore DBD-IA, which allowed us to create a new robust molecular nanogel thermometer for intracellular thermometry. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Control of body's center of mass motion relative to center of pressure during uphill walking in the elderly.

PubMed

Hong, Shih-Wun; Leu, Tsai-Hsueh; Wang, Ting-Ming; Li, Jia-Da; Ho, Wei-Pin; Lu, Tung-Wu

2015-10-01

Uphill walking places more challenges on the locomotor system than level walking does when the two limbs work together to ensure the stability and continuous progression of the body over the base of support. With age-related degeneration older people may have more difficulty in maintaining balance during uphill walking, and may thus experience an increased risk of falling. The current study aimed to investigate using gait analysis techniques to determine the effects of age and slope angles on the control of the COM relative to the COP in terms of their inclination angles (IA) and the rate of change of IA (RCIA) during uphill walking. The elderly were found to show IAs similar to those of the young, but with reduced self-selected walking speed and RCIAs (P<0.05). After adjusting for walking speed differences, the elderly showed significantly greater excursions of IA in the sagittal plane (P<0.05) and increased RCIA at heel-strike and during single limb support (SLS) and double limb support (DLS) in the sagittal plane (P<0.05), and increased RCIA at heel-strike in the frontal plane (P<0.05). The RCIAs were significantly reduced with increasing slope angles (P<0.05). The current results show that the elderly adopted a control strategy different from the young during uphill walking, and that the IA and RCIA during walking provide a sensitive measure to differentiate individuals with different balance control abilities. The current results and findings may serve as baseline data for future clinical and ergonomic applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Probing the distance-duality relation with high- z data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holanda, R.F.L.; Busti, V.C.; Lima, F.S.

2017-09-01

Measurements of strong gravitational lensing jointly with type Ia supernovae (SNe Ia) observations have been used to test the validity of the cosmic distance duality relation (CDDR), D{sub L}( z )/[(1+ z ){sup 2D{sub A}}( z )]=η=1, where D{sub L}(z) and D{sub A}(z) are the luminosity and the angular diameter distances to a given redshift z , respectively. However, several lensing systems lie in the interval 1.4 ≤ z ≤ 3.6 i.e., beyond the redshift range of current SNe Ia compilations ( z ≈ 1.50), which prevents this kind of test to be fully explored. In this paper, we circumventmore » this problem by testing the CDDR considering observations of strong gravitational lensing along with SNe Ia and (a subsample from) the latest gamma-ray burst distance modulus data, whose redshift range is 0.033 ≤ z ≤ 9.3. We parameterize their luminosity distances with a second degree polynomial function and search for possible deviations from the CDDR validity by using four different η( z ) functions: η( z )=1+η{sub 0z}, η( z )=1+η{sub 0z}/(1+ z ), η( z )=(1+ z ){sup η{sub 0}} and η( z )=1+η{sub 0ln}(1+ z ). Unlike previous tests done at redshifts lower than 1.50, the likelihood for η{sub 0} depends strongly on the η( z ) function considered, but we find no significant deviation from the CDDR validity (η{sub 0}=0). However, our analyses also point to the fact that caution is needed when one fits data in higher redshifts to test the CDDR as well as a better understanding of the mass distribution of lenses also is required for more accurate results.« less

Observational Constraints on the Unified Dark-Energy Dark-Matter Model

NASA Astrophysics Data System (ADS)

Wu, Pu-Xun; Yu, Hong-Wei

2007-03-01

We investigate the constraints on a generalized Chaplygin gas (GCG) model using the gold sample type-Ia supernovae (Sne Ia) data, the new Supernova Legacy Survey (SNLS) Sne Ia data and the size of baryonic acoustic oscillation peak found in Sloan Digital Sky Survey (SDSS). In a spatially flat universe case we obtain, at a 95.4% confidence level, As = 0.76-0.07+0.07 and α = 0.028-0.238+0.322. Our results are consistent with the ΛCDM model (α = 0), but rule out the standard Chaplygin gas model (α = 1).

Radio Observations of Type Ia SN2006X

NASA Astrophysics Data System (ADS)

Soderberg, Alicia

2006-02-01

Alicia Soderberg (Caltech) reports: I observed the Type Ia supernova 2006X in NGC 4321 (IAUC 8667, CBET 393) with the Very Large Array on 2006 February 9.34 UT (approximately 2 days after optical discovery). The 2.5 hour observation at 8.46 GHz reveals no radio source coincident with the optical SN position. I place a limit on the radio flux density of 45 microJy (3 sigma). At a distance of 16 Mpc this limit corresponds to a luminosity of 1.4 x 10^25 erg/s/Hz.

Cell-mediated immunity in herpes simplex virus-infected mice: H-2 mapping of the delayed-type hypersensitivity response and the antiviral T cell response.

PubMed

Nash, A A; Phelan, J; Wildy, P

1981-04-01

An adoptive transfer system was used to investigate the H-2 restriction of delayed-type hypersensitivity (DTH) to herpes simplex virus. A successful DTH transfer was achieved when donor and recipient were compatible at the I-A region, with K and D region compatibility unnecessary. However, the rapid clearance of infectious virus from the inoculation site was found only when the donor and recipients were compatible at H-2K (and presumably D) and I-A regions.

Brain stimulation to treat Internet addiction: A commentary.

PubMed

Trojak, Benoit; Zullino, Daniele; Achab, Sophia

2017-01-01

In February, 2015, French television screened a report on Internet addiction (IA) in which an individual, identifying himself as cyberdependent, was offered treatment with repetitive Transcranial Magnetic Stimulation (rTMS), a Non-Invasive Brain Stimulation (NIBS) technique. Two issues deserve to be emphasized. Firstly, the concept of IA is not unanimously recognized by scientists and has raised a number of questions. Secondly, although the first results suggest that brain stimulation techniques could be a potential therapy for Substance Use Disorders (SUDs), no data are available on the therapeutic effects of rTMS on IA or even excessive Internet use. Currently, we cannot promote the use of rTMS for Internet detoxification because there is no evidence to prove its efficacy. Nevertheless, the similarities between SUDs and IA, and the results of NIBS on SUDs suggest that research can be done to examine the efficacy of NIBS techniques to treat Internet gaming disorder and other forms of IA. Copyright © 2015 Elsevier Ltd. All rights reserved.

Should junior doctors strike?

PubMed

Toynbee, Mark; Al-Diwani, Adam Aj; Clacey, Joe; Broome, Matthew R

2016-03-01

An impasse in negotiations between the Department of Health (DoH) and the British Medical Association in November this year led to an overwhelming vote for industrial action (IA) by junior doctors. At the time of writing, a last minute concession by DoH led to a deferment of IA to allow further negotiations mediated by the Advisory, Conciliation and Arbitration Service. However, IA by junior doctors remains a possibility if these negotiations stall again. Would the proposed action be ethically justifiable? Furthermore, is IA by doctors ever ethically defendable? Building on previous work, we explore important ethical considerations for doctors considering IA. The primary moral objection to doctors striking is often claimed to be risk of harm to patients. Other common arguments against IA by doctors include breaching their vocational responsibilities and possible damage to their relationship with patients and the public in general. These positions are in turn countered by claims of a greater long-term good and the legal and moral rights of employees to strike. Absolute restrictions appear to be hard to justify in the modern context, as does an unrestricted right to IA. We review these arguments, find that some common moral objections to doctors striking may be less relevant to the current situation, that a stronger contemporary objection to IA might be from a position of social justice and suggest criteria for ethically permissible doctor IA. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Identity Abuse as a Tactic of Violence in LGBTQ Communities: Initial Validation of the Identity Abuse Measure.

PubMed

Woulfe, Julie M; Goodman, Lisa A

2018-03-01

Intimate partner violence (IPV; i.e., physical, sexual, or psychological abuse by a current or former partner) remains a public health concern with devastating personal and societal costs. Lesbian, gay, bisexual, transgender, and queer (LGBTQ) individuals are also vulnerable to a dimension of IPV called identity abuse (IA); that is, abuse tactics that leverage systemic oppression to harm an individual. Yet, we know little about its relative prevalence in subgroups of the LGBTQ community. This study developed and evaluated a measure of IA, and explored its prevalence in a sample of 734 sexual minority adults. The sample included women (53.1%), men (27.4%), and transgender or gender nonconforming "TGNC" (19.3%) participants. The majority of participants identified as queer or pansexual (38.7%), then gay (23.6%), lesbian (22.8%), and bisexual (13.6%). Participants completed an online survey that included measures of IA and physical, sexual, and psychological abuse. The IA items formed a unidimensional factor structure with strong internal consistency and construct validity. Nearly one fifth of the sample (16.8%) experienced past year IA and 40.1% reported adult IA. Women experienced greater exposure to IA in adulthood than men, and TGNC participants reported higher rates of IA in adulthood and in the last year compared to their cisgender counterparts. The odds of queer or bisexual participants reporting IA in adulthood were almost three times higher than gay participants, and two times higher than lesbian participants. Findings have implications for advancing assessment of partner abuse in the LGBTQ community, LGBTQ-competent clinical care, and training of practitioners.

Effects of n-alkanols and a methyl ester on a transient potassium (IA) current in identified neurones from Helix aspersa.

PubMed Central

Winpenny, J P; Elliott, J R; Harper, A A

1992-01-01

1. A two-microelectrode voltage clamp was used to determine the effects of n-butanol, n-hexanol, n-octanol, n-decanol and methyl hexanoate on a transient potassium (IA) current in identified Helix aspersa neurones. Experiments were carried out at a temperature of 10-12 degrees C. 2. Each n-alkanol reversibly reduced the amplitude of the IA current. Logarithmic dose-response curves for the current reduction by each homologue were sigmoidal and had slope factors of around four. The concentrations required to reduce the peak (with time) current at -30 mV by 50% (ED50 +/- fitted standard error) were: 57 +/- 5 mM (n-butanol); 2.0 +/- 0.1 mM (n-hexanol); 0.28 +/- 0.02 mM (n-octanol) and 0.016 +/- 0.001 mM (n-decanol). Methyl hexanoate also reduced the current amplitude, with an ED50 of 1-2 mM. The Helix IA current thus showed a similar sensitivity to n-alkanols to that of squid and rat sodium currents but was rather more sensitive than the squid delayed rectifier potassium current. 3. The n-alkanol ED50 concentrations were used to calculate a standard free energy per methylene group for adsorption to a site of action in the cell of -3.1 +/- 0.2 kJ/mol. This suggested a hydrophobic site or sites of action. The regularity of the change in free energy with chain length was maintained up to, and including, n-decanol. This implied that the site(s) could accommodate a ten-carbon chain as readily as an eight-carbon chain. 4. The voltage dependencies of IA current activation and steady-state inactivation were not consistently altered by treatment with n-alkanols at concentrations around or above their current suppression ED50 concentrations. 5. The kinetics of current activation and inactivation were affected, particularly by lower chain length compounds. At 60 mM n-butanol reduced the time constant for development of inactivation of open channels (tau b) by 56%, while 0.016 mM n-decanol produced only a 13% reduction. n-Butanol (60 mM) also caused a substantial (76%) reduction in the time constant for development of inactivation in channels which were presumed to be closed. The effects of n-alkanols on the current time-to-peak (tc) were complex, showing both increases and decreases, but these actions also declined with chain length. Methyl hexanoate (1 mM) reduced tau b by around 30% and tc by around 20%. 6. n-Alkanols have now been shown to inhibit a number of voltage-gated ion conductances.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:1293276

Uncertainties in Galactic Chemical Evolution Models

DOE PAGES

Cote, Benoit; Ritter, Christian; Oshea, Brian W.; ...

2016-06-15

Here we use a simple one-zone galactic chemical evolution model to quantify the uncertainties generated by the input parameters in numerical predictions for a galaxy with properties similar to those of the Milky Way. We compiled several studies from the literature to gather the current constraints for our simulations regarding the typical value and uncertainty of the following seven basic parameters: the lower and upper mass limits of the stellar initial mass function (IMF), the slope of the high-mass end of the stellar IMF, the slope of the delay-time distribution function of Type Ia supernovae (SNe Ia), the number ofmore » SNe Ia per M ⊙ formed, the total stellar mass formed, and the final mass of gas. We derived a probability distribution function to express the range of likely values for every parameter, which were then included in a Monte Carlo code to run several hundred simulations with randomly selected input parameters. This approach enables us to analyze the predicted chemical evolution of 16 elements in a statistical manner by identifying the most probable solutions along with their 68% and 95% confidence levels. Our results show that the overall uncertainties are shaped by several input parameters that individually contribute at different metallicities, and thus at different galactic ages. The level of uncertainty then depends on the metallicity and is different from one element to another. Among the seven input parameters considered in this work, the slope of the IMF and the number of SNe Ia are currently the two main sources of uncertainty. The thicknesses of the uncertainty bands bounded by the 68% and 95% confidence levels are generally within 0.3 and 0.6 dex, respectively. When looking at the evolution of individual elements as a function of galactic age instead of metallicity, those same thicknesses range from 0.1 to 0.6 dex for the 68% confidence levels and from 0.3 to 1.0 dex for the 95% confidence levels. The uncertainty in our chemical evolution model does not include uncertainties relating to stellar yields, star formation and merger histories, and modeling assumptions.« less

Acute Knockdown of Kv4.1 Regulates Repetitive Firing Rates and Clock Gene Expression in the Suprachiasmatic Nucleus and Daily Rhythms in Locomotor Behavior

PubMed Central

Hermanstyne, Tracey O.; Mellor, Rebecca L.

2017-01-01

Abstract Rapidly activating and inactivating A-type K+ currents (IA) encoded by Kv4.2 and Kv4.3 pore-forming (α) subunits of the Kv4 subfamily are key regulators of neuronal excitability. Previous studies have suggested a role for Kv4.1 α-subunits in regulating the firing properties of mouse suprachiasmatic nucleus (SCN) neurons. To test this, we utilized an RNA-interference strategy to knockdown Kv4.1, acutely and selectively, in the SCN. Current-clamp recordings revealed that the in vivo knockdown of Kv4.1 significantly (p < 0.0001) increased mean ± SEM repetitive firing rates in SCN neurons during the day (6.4 ± 0.5 Hz) and at night (4.3 ± 0.6 Hz), compared with nontargeted shRNA-expressing SCN neurons (day: 3.1 ± 0.5 Hz; night: 1.6 ± 0.3 Hz). IA was also significantly (p < 0.05) reduced in Kv4.1-targeted shRNA-expressing SCN neurons (day: 80.3 ± 11.8 pA/pF; night: 55.3 ± 7.7 pA/pF), compared with nontargeted shRNA-expressing (day: 121.7 ± 10.2 pA/pF; night: 120.6 ± 16.5 pA/pF) SCN neurons. The magnitude of the effect of Kv4.1-targeted shRNA expression on firing rates and IA was larger at night. In addition, Kv4.1-targeted shRNA expression significantly (p < 0.001) increased mean ± SEM nighttime input resistance (Rin; 2256 ± 166 MΩ), compared to nontargeted shRNA-expressing SCN neurons (1143 ± 93 MΩ). Additional experiments revealed that acute knockdown of Kv4.1 significantly (p < 0.01) shortened, by ∼0.5 h, the circadian period of spontaneous electrical activity, clock gene expression and locomotor activity demonstrating a physiological role for Kv4.1-encoded IA channels in regulating circadian rhythms in neuronal excitability and behavior. PMID:28560311

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cote, Benoit; Ritter, Christian; Oshea, Brian W.

Here we use a simple one-zone galactic chemical evolution model to quantify the uncertainties generated by the input parameters in numerical predictions for a galaxy with properties similar to those of the Milky Way. We compiled several studies from the literature to gather the current constraints for our simulations regarding the typical value and uncertainty of the following seven basic parameters: the lower and upper mass limits of the stellar initial mass function (IMF), the slope of the high-mass end of the stellar IMF, the slope of the delay-time distribution function of Type Ia supernovae (SNe Ia), the number ofmore » SNe Ia per M ⊙ formed, the total stellar mass formed, and the final mass of gas. We derived a probability distribution function to express the range of likely values for every parameter, which were then included in a Monte Carlo code to run several hundred simulations with randomly selected input parameters. This approach enables us to analyze the predicted chemical evolution of 16 elements in a statistical manner by identifying the most probable solutions along with their 68% and 95% confidence levels. Our results show that the overall uncertainties are shaped by several input parameters that individually contribute at different metallicities, and thus at different galactic ages. The level of uncertainty then depends on the metallicity and is different from one element to another. Among the seven input parameters considered in this work, the slope of the IMF and the number of SNe Ia are currently the two main sources of uncertainty. The thicknesses of the uncertainty bands bounded by the 68% and 95% confidence levels are generally within 0.3 and 0.6 dex, respectively. When looking at the evolution of individual elements as a function of galactic age instead of metallicity, those same thicknesses range from 0.1 to 0.6 dex for the 68% confidence levels and from 0.3 to 1.0 dex for the 95% confidence levels. The uncertainty in our chemical evolution model does not include uncertainties relating to stellar yields, star formation and merger histories, and modeling assumptions.« less

Pregnancies in Glycogen Storage Disease Type Ia

PubMed Central

Martens, Daniëlle HJ; Rake, Jan Peter; Schwarz, Martin; Ullrich, Kurt; Weinstein, David A; Merkel, Martin; Sauer, Pieter JJ; Smit, G Peter A

2013-01-01

Objective Reports on pregnancies in women with GSD-Ia are scarce. Due to improved life expectancy, pregnancy is becoming an important issue. We describe 15 pregnancies focusing on dietary treatment, biochemical parameters and GSD-Ia complications. Study Design Carbohydrate requirements (mg/kg/min), triglyceride and uric acid levels, liver ultrasonography and creatinine clearance were investigated before, during and after pregnancy. Data of the newborns were obtained from the records. Results In the first trimester, a significant increase in carbohydrate requirements was observed (p=0,007). Most patients had acceptable triglyceride and uric acid levels during pregnancy. No increase in size/number of adenomas was seen. In 3/4 patients, a decrease in GFR was observed after pregnancy. In three pregnancies, lactic acidosis developed during delivery with severe multi-organ failure in one. All but one of the children are healthy and show good psychomotor development. Conclusion Successful pregnancies are possible in GSD-Ia patients, although specific GSD-Ia related risks are present. PMID:18241814

Supernova spectra below strong circumstellar interaction

NASA Astrophysics Data System (ADS)

Leloudas, G.; Hsiao, E. Y.; Johansson, J.; Maeda, K.; Moriya, T. J.; Nordin, J.; Petrushevska, T.; Silverman, J. M.; Sollerman, J.; Stritzinger, M. D.; Taddia, F.; Xu, D.

2015-02-01

We construct spectra of supernovae (SNe) interacting strongly with a circumstellar medium (CSM) by adding SN templates, a black-body continuum, and an emission-line spectrum. In a Monte Carlo simulation we vary a large number of parameters, such as the SN type, brightness and phase, the strength of the CSM interaction, the extinction, and the signal to noise ratio (S/N) of the observed spectrum. We generate more than 800 spectra, distribute them to ten different human classifiers, and study how the different simulation parameters affect the appearance of the spectra and their classification. The SNe IIn showing some structure over the continuum were characterized as "SNe IInS" to allow for a better quantification. We demonstrate that the flux ratio of the underlying SN to the continuum fV is the single most important parameter determining whether a spectrum can be classified correctly. Other parameters, such as extinction, S/N, and the width and strength of the emission lines, do not play a significant role. Thermonuclear SNe get progressively classified as Ia-CSM, IInS, and IIn as fV decreases. The transition between Ia-CSM and IInS occurs at fV ~ 0.2-0.3. It is therefore possible to determine that SNe Ia-CSM are found at the (un-extincted) magnitude range -19.5 >M> -21.6, in very good agreement with observations, and that the faintest SN IIn that can hide a SN Ia has M = -20.1. The literature sample of SNe Ia-CSM shows an association with 91T-like SNe Ia. Our experiment does not support that this association can be attributed to a luminosity bias (91T-like being brighter than normal events). We therefore conclude that this association has real physical origins and we propose that 91T-like explosions result from single degenerate progenitors that are responsible for the CSM. Despite the spectroscopic similarities between SNe Ibc and SNe Ia, the number of misclassifications between these types was very small in our simulation and mostly at low S/N. Combined with the SN luminosity function needed to reproduce the observed SN Ia-CSM luminosities, it is unlikely that SNe Ibc constitute an important contaminant within this sample. We show how Type II spectra transition to IIn and how the Hα profiles vary with fV. SNe IIn fainter than M = -17.2 are unable to mask SNe IIP brighter than M = -15. A more advanced simulation, including radiative transfer, shows that our simplified model is a good first order approximation. The spectra obtained are in good agreement with real data.

Complete renal tubular acidosis late after kidney transplantation.

PubMed

Schwarz, Christoph; Benesch, Thomas; Kodras, Katharina; Oberbauer, Rainer; Haas, Martin

2006-09-01

Neither the prevalence nor the associated risk factors of late post-transplant renal tubular acidosis (RTA) are known. We conducted a cross-sectional study with 576 patients for more than 12 months after kidney transplantation, and a glomerular filtration rate (GFR) >40 ml/min. RTA was diagnosed by measurement of the urine anionic gap, urine pH and plasma potassium during acidosis, and fractional bicarbonate excretion after bicarbonate loading. Uni- and multi-variable analysis were used to isolate factors associated with post-transplant RTA, and with the different RTA subtypes. All patients (n = 76) had distal post-transplant RTA. A significant association with the presence of RTA was found for the intake of tacrolimus or renin-angiotensin-aldosterone blockers, the Parathyroid hormone level and the GFR. Type Ia (classic, distal), type Ib (hyperkalaemic, voltage-dependent), rate-limited and type IV RTA were present in 37, 14, 21 and 28% of the patients. Acute transplant rejection was the only significant different parameter between the RTA subtypes and more often present in patients with type Ia or Ib RTA. We conclude that a significant fraction of stable long-term renal transplant recipients with adequate graft function develop post-transplant RTA, with a preponderance for type Ia and type IV, and absence of type II. In addition, acute transplant rejection seems to have an influence on the subtype of RTA present post-transplantation.

Hubble Space Telescope studies of low-redshift Type Ia supernovae: evolution with redshift and ultraviolet spectral trends

NASA Astrophysics Data System (ADS)

Maguire, K.; Sullivan, M.; Ellis, R. S.; Nugent, P. E.; Howell, D. A.; Gal-Yam, A.; Cooke, J.; Mazzali, P.; Pan, Y.-C.; Dilday, B.; Thomas, R. C.; Arcavi, I.; Ben-Ami, S.; Bersier, D.; Bianco, F. B.; Fulton, B. J.; Hook, I.; Horesh, A.; Hsiao, E.; James, P. A.; Podsiadlowski, P.; Walker, E. S.; Yaron, O.; Kasliwal, M. M.; Laher, R. R.; Law, N. M.; Ofek, E. O.; Poznanski, D.; Surace, J.

2012-11-01

We present an analysis of the maximum light, near-ultraviolet (NUV; 2900 < λ < 5500 Å) spectra of 32 low-redshift (0.001 < z < 0.08) Type Ia supernovae (SNe Ia), obtained with the Hubble Space Telescope (HST) using the Space Telescope Imaging Spectrograph. We combine this spectroscopic sample with high-quality gri light curves obtained with robotic telescopes to measure SN Ia photometric parameters, such as stretch (light-curve width), optical colour and brightness (Hubble residual). By comparing our new data to a comparable sample of SNe Ia at intermediate redshift (0.4 < z < 0.9), we detect modest spectral evolution (3σ), in the sense that our mean low-redshift NUV spectrum has a depressed flux compared to its intermediate-redshift counterpart. We also see a strongly increased dispersion about the mean with decreasing wavelength, confirming the results of earlier surveys. We show that these trends are consistent with changes in metallicity as predicted by contemporary SN Ia spectral models. We also examine the properties of various NUV spectral diagnostics in the individual SN spectra. We find a general correlation between SN stretch and the velocity (or position) of many NUV spectral features. In particular, we observe that higher stretch SNe have larger Ca II H&K velocities, which also correlate with host galaxy stellar mass. This latter trend is probably driven by the well-established correlation between stretch and host galaxy stellar mass. We find no significant trends between UV spectral features and optical colour. Mean spectra constructed according to whether the SN has a positive or negative Hubble residual show very little difference at NUV wavelengths, indicating that the NUV evolution and variation we identify does not directly correlate with Hubble diagram residuals. Our work confirms and strengthens earlier conclusions regarding the complex behaviour of SNe Ia in the NUV spectral region, but suggests the correlations we find are more useful in constraining progenitor models rather than improving the use of SNe Ia as cosmological probes.

Explaining the progenitors of peculiar type Ia supernovae

NASA Astrophysics Data System (ADS)

Das, Upasana; Mukhopadhyay, Banibrata

2015-01-01

Type Ia supernovae (SneIa) are believed to be triggered in white dwarfs having mass close to the Chandrasekhar limit of 1.44 M⊙. However, observations of several peculiar, highly under- and over-luminous SNeIa argue for exploding masses widely different from this limit. The over-luminous SNeIa, e.g. SN 2003fg, SN 2006gz, SN 2007if, SN 2009dc, seem to invoke super-Chandrasekhar white dwarf progenitors, having mass 2.1-2.8 M⊙. While, the under-luminous SNeIa, e.g. SN 1991bg, SN 1997cn, SN 1998de, SN 1999by, seem to favor sub-Chandrasekhar explosion scenarios. In order to explain the existence of super-Chandrasekhar white dwarfs, we have exploited the enormous potential of magnetic fields, which can affect the structure and properties of the underlying white dwarf in a variety of ways. We have progressed from a simplistic to more rigorous and self-consistent models in the following sequence - spherically symmetric Newtonian model with a constant central magnetic field; spherically symmetric general relativistic model with varying magnetic field and finally, a model including self-consistent departure from spherical symmetry obtained from general relativistic magnetohydrodynamic (GRMHD) simulations. Here we particularly present the results of the GRMHD simulations, whereby we have constructed equilibrium models of strongly magnetized, static, white dwarfs. Interestingly, we find that significantly super-Chandrasekhar white dwarfs are obtained for many possible field configurations, namely, poloidal, toroidal and mixed. Further, due to the inclusion of deformation in the white dwarf structure caused by a strong magnetic field, super-Chandrasekhar white dwarfs are obtained for relatively lower magnetic field strengths compared to that in the simplistic model. Finally, driven by the aim to establish a unification theory of under- and over-luminous SNeIa, we have shown that a modification of Einstein's theory of gravity leads to both significantly sub- and super-Chandrasekhar limiting masses, determined by a single model parameter. Explosions of these sub- and super-Chandrasekhar limiting mass white dwarfs can explain both the peculiar, under- and over-luminous SNeIa respectively.

MONTE CARLO POPULATION SYNTHESIS OF POST-COMMON-ENVELOPE WHITE DWARF BINARIES AND TYPE Ia SUPERNOVA RATE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ablimit, Iminhaji; Maeda, Keiichi; Li, Xiang-Dong

Binary population synthesis (BPS) studies provide a comprehensive way to understand the evolution of binaries and their end products. Close white dwarf (WD) binaries have crucial characteristics for examining the influence of unresolved physical parameters on binary evolution. In this paper, we perform Monte Carlo BPS simulations, investigating the population of WD/main-sequence (WD/MS) binaries and double WD binaries using a publicly available binary star evolution code under 37 different assumptions for key physical processes and binary initial conditions. We considered different combinations of the binding energy parameter ( λ {sub g}: considering gravitational energy only; λ {sub b}: considering bothmore » gravitational energy and internal energy; and λ {sub e}: considering gravitational energy, internal energy, and entropy of the envelope, with values derived from the MESA code), CE efficiency, critical mass ratio, initial primary mass function, and metallicity. We find that a larger number of post-CE WD/MS binaries in tight orbits are formed when the binding energy parameters are set by λ {sub e} than in those cases where other prescriptions are adopted. We also determine the effects of the other input parameters on the orbital periods and mass distributions of post-CE WD/MS binaries. As they contain at least one CO WD, double WD systems that evolved from WD/MS binaries may explode as type Ia supernovae (SNe Ia) via merging. In this work, we also investigate the frequency of two WD mergers and compare it to the SNe Ia rate. The calculated Galactic SNe Ia rate with λ = λ {sub e} is comparable to the observed SNe Ia rate, ∼8.2 × 10{sup 5} yr{sup 1} – ∼4 × 10{sup 3} yr{sup 1} depending on the other BPS parameters, if a DD system does not require a mass ratio higher than ∼0.8 to become an SNe Ia. On the other hand, a violent merger scenario, which requires the combined mass of two CO WDs ≥ 1.6 M {sub ⊙} and a mass ratio >0.8, results in a much lower SNe Ia rate than is observed.« less

Time-varying sodium absorption in the Type Ia supernova 2013gh

DOE PAGES

Ferretti, Raphael; Amanullah, R.; Goobar, A.; ...

2016-07-18

Context. Temporal variability of narrow absorption lines in high-resolution spectra of Type Ia supernovae (SNe Ia) is studied to search for circumstellar matter. Time series which resolve the profiles of absorption lines such as Na I D or Ca II H&K are expected to reveal variations due to photoionisation and subsequent recombination of the gases. The presence, composition, and geometry of circumstellar matter may hint at the elusive progenitor system of SNe Ia and could also affect the observed reddening law. Aims. To date, there are few known cases of time-varying Na I D absorption in SNe Ia, all ofmore » which occurred during relatively late phases of the supernova (SN) evolution. Photoionisation, however, is predicted to occur during the early phases of SNe Ia, when the supernovae peak in the ultraviolet. We attempt, therefore, to observe early-time absorption-line variations by obtaining high-resolution spectra of SNe before maximum light. Methods. In this paper, we have obtained photometry and high-resolution spectroscopy of SNe Ia 2013gh and iPTF 13dge, to search for absorption-line variations. Furthermore, we study interstellar absorption features in relation to the observed photometric colours of the SNe. Results. Both SNe display deep Na I D and Ca II H&K absorption features. Furthermore, small but significant variations are detected in a feature of the Na I D profile of SN 2013gh. The variations are consistent with either geometric effects of rapidly moving or patchy gas clouds or photoionisation of Na I gas at R ≈ 10 19 cm from the explosion. Conclusions. Our analysis indicates that it is necessary to focus on early phases to detect photoionisation effects of gases in the circumstellar medium of SNe Ia. Different absorbers such as Na I and Ca II can be used to probe for matter at different distances from the SNe. Finally, the nondetection of variations during early phases makes it possible to put limits on the abundance of the species at those distances.« less

Solar abundance ratios of the iron-peak elements in the Perseus cluster.

PubMed

2017-11-23

The metal abundance of the hot plasma that permeates galaxy clusters represents the accumulation of heavy elements produced by billions of supernovae. Therefore, X-ray spectroscopy of the intracluster medium provides an opportunity to investigate the nature of supernova explosions integrated over cosmic time. In particular, the abundance of the iron-peak elements (chromium, manganese, iron and nickel) is key to understanding how the progenitors of typical type Ia supernovae evolve and explode. Recent X-ray studies of the intracluster medium found that the abundance ratios of these elements differ substantially from those seen in the Sun, suggesting differences between the nature of type Ia supernovae in the clusters and in the Milky Way. However, because the K-shell transition lines of chromium and manganese are weak and those of iron and nickel are very close in photon energy, high-resolution spectroscopy is required for an accurate determination of the abundances of these elements. Here we report observations of the Perseus cluster, with statistically significant detections of the resonance emission from chromium, manganese and nickel. Our measurements, combined with the latest atomic models, reveal that these elements have near-solar abundance ratios with respect to iron, in contrast to previous claims. Comparison between our results and modern nucleosynthesis calculations disfavours the hypothesis that type Ia supernova progenitors are exclusively white dwarfs with masses well below the Chandrasekhar limit (about 1.4 times the mass of the Sun). The observed abundance pattern of the iron-peak elements can be explained by taking into account a combination of near- and sub-Chandrasekhar-mass type Ia supernova systems, adding to the mounting evidence that both progenitor types make a substantial contribution to cosmic chemical enrichment.

Bianchi Type-I Anisotropic Dark Energy Model with Constant Deceleration Parameter

NASA Astrophysics Data System (ADS)

Pradhan, Anirudh; Amirhashchi, H.; Saha, Bijan

2011-09-01

A new dark energy model in anisotropic Bianchi type-I (B-I) space-time with time dependent equation of state (EoS) parameter and constant deceleration parameter has been investigated in the present paper. The Einstein's field equations have been solved by applying a variation law for generalized Hubble's parameter (Berman in Il Nuovo Cimento B 74:182, 1983) which generates two types of solutions, one is of power-law type and other is of the exponential form. The existing range of the dark energy EoS parameter ω for derived model is found to be in good agreement with the three recent observations (i) SNe Ia data (Knop et al. in Astrophys. J. 598:102, 2003), (ii) SNe Ia data collaborated with CMBR anisotropy and galaxy clustering statistics (Tegmark et al. in Astrophys. J. 606:702, 2004) and (iii) a combination of cosmological datasets coming from CMB anisotropies, luminosity distances of high redshift type Ia supernovae and galaxy clustering (Hinshaw et al. in Astrophys. J. Suppl. Ser. 180:225, 2009 and Komatsu et al. in Astrophys. J. Suppl. Ser. 180:330, 2009). The cosmological constant Λ is found to be a decreasing function of time and it approaches a small positive value at the present epoch which is corroborated by results from recent supernovae Ia observations. It has also been suggested that the dark energy that explains the observed accelerating universe may arise due to the contribution to the vacuum energy of the EoS in a time dependent background. Geometric and kinematic properties of the model and the behaviour of the anisotropy of the dark energy have been carried out.