bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unveiling the fundamental properties of Gamma-Ray Burst host galaxies
Authors: Savaglio Sandra 
Published: September 2012

AbstractThe galaxies hosting the most energetic explosions in the universe, the gamma-ray bursts (GRBs), are generally found to be low-mass, metal-poor, blue and star forming. However, the majority of the targets investigated so far (less than 100) are at relatively low redshift, z < 2. We know that at low redshift, the cosmic star formation is predominantly in small galaxies. Therefore, at low redshift, long-duration GRBs, which are associated with massive stars, are expected to be in small galaxies. Preliminary investigations of the stellar mass function of z < 1.5 GRB hosts does not indicate that these galaxies are different from the general population of nearby star-forming galaxies. At high-z, it is still unclear whether GRB hosts are different. Recent results indicate that a fraction of them might be in dusty regions of massive galaxies. Remarkable is the a super-solar metallicity measured in the interstellar medium of a z = 3.57 GRB host.
Probing explosion geometry of core-collapse supernovae with light curves of the shock breakout
Authors: Suzuki Akihiro , Shigeyama Toshikazu 
Published: September 2012

AbstractWe consider supernova shock breakout in aspherical core-collapse supernovae. We perform hydrodynamical calculations to investigate the propagation of a strong shock wave in a compact star and the subsequent emergence from the surface. Using the results combined with a simple emission model based on blackbody radiation, we clarify how aspherical energy depositions affect shock breakout light curves.
Are short GRBs powered by magnetars?
Authors: O'Brien Paul T. , Rowlinson Antonia 
Published: September 2012

AbstractThe standard model for a short duration Gamma-Ray Burst (GRB) involves the merger of a neutron star binary system, resulting in a black hole which accretes for a brief period of time. However, some of the short-duration GRBs observed by the Swift satellite show features in their light curves which are difficult to explain in this model. As an alternative, we examine the light curves of the Swift short GRB sample to see if they can be explained by the presence of a highly magnetised, rapidly rotating pulsar, or magnetar. We find that magnetars may be present in a large fraction of short bursts, and discuss briefly how this model can be tested using the next generation of gravity-wave observatories.
Detecting TeV γ-rays from GRBs with km3 neutrino telescopes
Authors: Astraatmadja Tri L. 
Published: September 2012

AbstractObserving TeV photons from GRBs can greatly enhance our understanding of their emission mechanisms. Under-sea/ice neutrino telescopes—such as ANTARES in the Mediterranean Sea or IceCube at the South Pole—can also operate as a γ-ray observatory by detecting downgoing muons from the electromagnetic cascade induced by the interaction of the photons with the Earth's atmosphere. Theoretical calculations of the number of detectable muons from single GRB events, located at different redshifts and zenith distances, have been performed. The attenuation by pair production of TeV photons with cosmic infrared background photons has also been included.
Neutron Star Kicks Affected by Standing Accretion Shock Instability for Core-Collapse Supernovae
Authors: Nakano Wakana Iwakami , Kotake Kei , Ohnishi Naofumi , Yamada Shoichi , Sawada Keisuke 
Published: September 2012

AbstractWe investigate a proto-neutron star kick velocity estimated from kinetic momentum of a flow around the proto-neutron star after the standing accretion shock instability grows. In this study, ten different types of random perturbations are imposed on the initial flow for each neutrino luminosity. We found that the kick velocities of proto-neutron star are widely distributed from 40 km s−1 to 180 km s−1 when the shock wave reaches 2000 km away from the center of the star. The average value of kick velocity is 115 km s−1, whose value is smaller than the observational ones. The kick velocities do not depend on the neutrino luminosity.
Progenitors of electron-capture supernovae
Authors: Jones Samuel , Hirschi Raphael , Herwig Falk , Paxton Bill , Timmes Francis X. , Nomoto Ken'ichi 
Published: September 2012

AbstractWe investigate the lowest mass stars that produce Type-II supernovae, motivated by recent results showing that a large fraction of type-II supernova progenitors for which there are direct detections display unexpectedly low luminosity (for a review see e.g. Smartt 2009). There are three potential evolutionary channels leading to this fate. Alongside the standard ‘massive star’ Fe-core collapse scenario we investigate the likelihood of electron capture supernovae (EC-SNe) from super-AGB (S-AGB) stars in their thermal pulse phase, from failed massive stars for which neon burning and other advanced burning stages fail to prevent the star from contracting to the critical densities required to initiate rapid electron-capture reactions and thus the star's collapse. We find it indeed possible that both of these relatively exotic evolutionary channels may be realised but it is currently unclear for what proportion of stars. Ultimately, the supernova light curves, explosion energies, remnant properties (see e.g. Knigge et al. 2011) and ejecta composition are the quantities desired to establish the role that these stars at the lower edge of the massive star mass range play.
Influence of stellar oscillations on pulsar and magnetar magnetospheres
Authors: Morozova Viktoriya , Ahmedov Bobomurat , Zanotti Olindo 
Published: September 2012

AbstractWe investigated influence of stellar oscillations on the electrodynamics of pulsars as well as magnetars magnetosphere. Besides finding noticeable modification of electromagnetic field and charge density in the polar cap vicinity of oscillating neutron stars we proposed qualitative hypotheses explaining phenomena of part time pulsars as well as sporadic radio emission from generally radio-quiet magnetars with the help of stellar oscillations.
The Fast Evolution of SN 2010bh associated with GRB 100316D
Authors: Olivares E. Felipe , Greiner Jochen , Schady Patricia , Rau Arne , Klose Sylvio , Krühler Thomas ,   for the GROND team
Published: September 2012

AbstractWe report on the type-Ic SN 2010bh associated with XRF 100316D at z = 0.059, which is among the latest spectroscopically confirmed GRB-SNe (Bufano et al. 2012). This supernova proves to be the most rapidly evolving GRB-SN to date.
The Red Supergiant Problem: Circumstellar dust as a solution
Authors: Walmswell Joe , Eldridge John 
Published: September 2012

AbstractWe investigate the red supergiant problem: the apparent dearth of Type IIP supernova progenitors with masses between 16 and 30 M⊙. Although red supergiants with masses in this range have been observed, none have been identified as progenitors in pre–explosion images. We show that, by failing to take into account the additional extinction resulting from the dust produced in the red supergiant winds, the luminosity of the most massive red supergiants at the end of their lives is underestimated. We re–estimate the initial masses of all Type IIP progenitors for which observations exist and analyse the resulting population. We find that the most likely maximum mass for a Type IIP progenitor is 21+2−1 M⊙. This is in closer agreement with the limit predicted from single star evolution models.
Rapid post‐mortem maturation of diatom silica oxygen isotope values
Authors: Dodd Justin P. , Sharp Zachary D. , Fawcett Peter J. , Brearley Adrian J. , McCubbin Francis M. 
Published: September 2012

Oxygen isotope values of diatom silica (δ18Odiatom) are increasingly used as paleoclimate proxies; however, the magnitude and timing of post‐mortem alteration of δ18Odiatom values has been unclear. In freshwater diatom silica from a human‐made pond in northern New Mexico, post‐mortem alteration of δ18Odiatom values occurs within one year of sediment burial. Diatom silica collected antemortem has an average δ18Odiatom value of 21.5‰ (VSMOW, σ = 1.3, n = 23), whereas diatom silica from two sediment cores from the same freshwater environment records significantly higher δ18Odiatom values (28.9‰, σ = 0.8, n = 13). The difference in ante‐ and post‐mortem δ18Odiatom values indicate post‐mortem alteration of diatom silica oxygen that results in a >7‰ increase in δ18O values. This study demonstrates that δ18Odiatom values reach mature values within 0.5 years of frustule death. Initial diatom δ18O values that record growing conditions are rapidly overwritten during silica maturation, and the mature diatom δ18O values approach isotopic equilibrium for quartz‐water. The rapid post‐mortem alteration of diatom δ18O values explains much of the disparate data regarding silica‐water fractionation for diatom silica and has a profound effect on the use of diatom silica δ18O values as a paleoclimate proxy in lacustrine and marine environments.
Snow dunes: A controlling factor of melt pond distribution on Arctic sea ice
Authors: Petrich Chris , Eicken Hajo , Polashenski Christopher M. , Sturm Matthew , Harbeck Jeremy P. , Perovich Donald K. , Finnegan David C. 
Published: September 2012

The location of snow dunes over the course of the ice‐growth season 2007/08 was mapped on level landfast first‐year sea ice near Barrow, Alaska. Landfast ice formed in mid‐December and exhibited essentially homogeneous snow depths of 4–6 cm in mid‐January; by early February distinct snow dunes were observed. Despite additional snowfall and wind redistribution throughout the season, the location of the dunes was fixed by March, and these locations were highly correlated with the distribution of meltwater ponds at the beginning of June. Our observations, including ground‐based light detection and ranging system (lidar) measurements, show that melt ponds initially form in the interstices between snow dunes, and that the outline of the melt ponds is controlled by snow depth contours. The resulting preferential surface ablation of ponded ice creates the surface topography that later determines the melt pond evolution.
Direct observation of hydrogen atom dynamics and interactions by ultrahigh resolution neutron protein crystallography
Authors: Chen Julian C.-H. , Hanson B. Leif , Fisher S. Zoë , Langan Paul , Kovalevsky Andrey Y. 
Published: September 2012

The 1.1 Å, ultrahigh resolution neutron structure of hydrogen/deuterium (H/D) exchanged crambin is reported. Two hundred ninety-nine out of 315, or 94.9%, of the hydrogen atom positions in the protein have been experimentally derived and resolved through nuclear density maps. A number of unconventional interactions are clearly defined, including a potential O─H…π interaction between a water molecule and the aromatic ring of residue Y44, as well as a number of potential C─H…O hydrogen bonds. Hydrogen bonding networks that are ambiguous in the 0.85 Å ultrahigh resolution X-ray structure can be resolved by accurate orientation of water molecules. Furthermore, the high resolution of the reported structure has allowed for the anisotropic description of 36 deuterium atoms in the protein. The visibility of hydrogen and deuterium atoms in the nuclear density maps is discussed in relation to the resolution of the neutron data.
Molecular mechanisms of cobalt-catalyzed hydrogen evolution
Authors: Marinescu Smaranda C. , Winkler Jay R. , Gray Harry B. 
Published: September 2012

Several cobalt complexes catalyze the evolution of hydrogen from acidic solutions, both homogeneously and at electrodes. The detailed molecular mechanisms of these transformations remain unresolved, largely owing to the fact that key reactive intermediates have eluded detection. One method of stabilizing reactive intermediates involves minimizing the overall reaction free-energy change. Here, we report a new cobalt(I) complex that reacts with tosylic acid to evolve hydrogen with a driving force of just 30 meV/Co. Protonation of Co
I
produces a transient Co
III
-H complex that was characterized by nuclear magnetic resonance spectroscopy. The Co
III
-H intermediate decays by second-order kinetics with an inverse dependence on acid concentration. Analysis of the kinetics suggests that Co
III
-H produces hydrogen by two competing pathways: a slower homolytic route involving two Co
III
-H species and a dominant heterolytic channel in which a highly reactive Co
II
-H transient is generated by Co
I
reduction of Co
III
-H.
Couch-based motion compensation: modelling, simulation and real-time experiments
Authors: Haas Olivier C L , Skworcow Piotr , Paluszczyszyn Daniel , Sahih Abdelhamid , Ruta Mariusz , Mills John A 
Published: September 2012

Abstract
The paper presents a couch-based active motion compensation strategy evaluated in simulation and validated experimentally using both a research and a clinical Elekta Precise Table™. The control strategy combines a Kalman filter to predict the surrogate motion used as a reference by a linear model predictive controller with the control action calculation based on estimated position and velocity feedback provided by an observer as well as predicted couch position and velocity using a linearized state space model. An inversion technique is used to compensate for the dead-zone nonlinearity. New generic couch models are presented and applied to model the Elekta Precise Table™ dynamics and nonlinearities including dead zone. Couch deflection was measured for different manufacturers and found to be up to 25 mm. A feed-forward approach is proposed to compensate for such couch deflection. Simultaneous motion compensation for longitudinal, lateral and vertical motions was evaluated using arbitrary trajectories generated from sensors or loaded from files. Tracking errors were between 0.5 and 2 mm RMS. A dosimetric evaluation of the motion compensation was done using a sinusoidal waveform. No notable differences were observed between films obtained for a fixed- or motion-compensated target. Further dosimetric improvement could be made by combining gating, based on tracking error together with beam on/off time, and PSS compensation.
Extended cleavage specificity of the mast cell chymase from the crab-eating macaque (Macaca fascicularis): an interesting animal model for the analysis of the function of the human mast cell chymase
Authors: Thorpe Michael , Yu Jing , Boinapally Vamsi , Ahooghalandari Parvin , Kervinen Jukka , Garavilla Lawrence de , Hellman Lars 
Published: September 2012

Abstract
Serine proteases are the major protein constituents within mast cell secretory granules. These proteases are subdivided into chymases and tryptases depending on their primary cleavage specificity. Here, we present the extended cleavage specificity of the macaque mast cell chymase and compare the specificity with human chymase (HC) and dog chymase (DC) that were produced in the same insect cell expression host. The macaque chymase (MC) shows almost identical characteristics as the HC, including both primary and extended cleavage specificities as well as sensitivity to protease inhibitors, whereas the DC differs in several of these characteristics. Although previous studies have shown that mouse mast cell protease-4 (mMCP-4) is similar in its hydrolytic specificity to the HC, mouse mast cells contain several related enzymes. Thus mice may not be the most appropriate model organism for studying HC activity and inhibition. Importantly, macaques express only one chymase and, as primates, are closely related to human general physiology. In addition, the human and macaque enzymes both cleave angiotensin I (Ang I) in the same way, generating primarily angiotensin II (Ang II) and they do not further degrade the peptide like most rodent enzymes do. Both enzymes also cleave two additional potential in vivo substrates, fibronectin and secretory leukocyte protease inhibitor (SLPI) in a similar way. Given the fact that both HC and MC are encoded by a single gene with high sequence homology and that many physiological processes are similar between these species, the macaque may be a very interesting model to study the physiological role of the chymase and to determine the potency and potential side-effects of various chymase inhibitors designed for therapeutic human use.
The single nucleotide polymorphism CRTh2 rs533116 is associated with allergic asthma and increased expression of CRTh2
Authors: Campos Alberto E. , MacLean E. , Davidson C. , Palikhe N. S. , Storie J. , Tse C. , Brenner D. , Mayers I. , Vliagoftis H. , El‐Sohemy A. , Cameron L. 
Published: September 2012

AbstractBackgroundCRTh2 (chemoattractant‐receptor homologous molecule expressed on Th2 cells) is expressed by Th2 cells and other cells involved in allergic inflammation. Single nucleotide polymorphisms (SNPs) in CRTh2 (rs11571288, rs545659, rs634681) have been associated with various phenotypes of allergy in ethnically distinct populations. Here, we assessed the association between CRTh2 rs533116 and allergic asthma, expression of CRTh2 and Th2 cytokine production.MethodsCRTh2 rs533116 was genotyped in an ethnically diverse population (n = 1282). The proportion of cells expressing CRTh2 was determined in peripheral blood from subjects with allergic airways disease and controls as well as with in vitro differentiated Th2 cells. Receptor function was assessed by stimulating Th2 cells with the CRTh2‐specific agonist 13,14‐dihydro‐15‐keto‐PGD2 (DK‐PGD2) and measuring IL‐4 and IL‐13 by intracellular staining and ELISA.ResultsCRTh2 rs533116 was associated with allergic asthma in White people (2.67 [1.09–6.55], P < 0.05), and expression of CRTh2 was higher in subjects with allergic airways disease compared to controls (P < 0.05). Among allergic individuals, the AA genotype was significantly associated with more eosinophils and higher expression of CRTh2 by both CD4+ T cells and eosinophils (P < 0.05). In vitro, the AA genotype was associated with a higher proportion of CRTh2+ cells during Th2 differentiation as well as more IL‐4 and IL‐13 expression following DK‐PGD2 stimulation (P < 0.05).ConclusionsThese findings show an association between CRTh2 rs533116 and allergic asthma and suggest this may be mediated by elevated expression of CRTh2, leading to higher numbers of circulating eosinophils and Th2 cytokine production.
The effects of six electronic apex locators on pacemaker function: an in vitro study
Authors: Gomez G. , Duran‐Sindreu F. , Jara Clemente F. , Garofalo R. R. , Garcia M. , Bueno R. , Roig M. 
Published: September 2012

AbstractAimTo assess the effects of six electronic apex locators (EALs) on pacemaker function in vitro.MethodologySix EALs (Mini Apex Locator®, Dentaport ZX®, Novapex®, Raypex5®, Root ZX mini®, and Justy II®) were tested for electromagnetic interference (EMI) with one pacemaker (Saint Jude Medical). The pacemaker, with a single electrode, was immersed in a saline solution bath adjusted to 400–800 ohms to simulate the electrical resistance of the human body and to register the activity by the system. The pacemaker was tested with each of the EALs to analyse the presence of EMI with the EAL switched on, the EAL switched off and during EAL operation. Each series of tests began with a 15‐second baseline recording (R0) and continued until all the recording conditions had been covered. The conditions were as follows: R1: recording with the lead of the EAL <2 cm from the tip of the electrode; R2: recording with the lead of the EAL <2 cm from the generator; R3: recording with the lead of the EAL <2 cm from the sensing arc; and R4: recording with the lead of the EAL 15 cm from the sensing arc. If any of the EALs produced interference, its characteristics were categorized.ResultsWhen the lead of the EAL was <2 cm from the tip of the electrode, the majority of the EALs tested produced only background noise. Only one (the Mini Apex Locator) resulted in EMI that was detected as false heart activity. When the EAL was <2 cm from the generator, just one EAL detected background noise (the Mini Apex Locator). When the EAL was <2 cm from the sensing arc or 15 cm from the sensing arc, the recordings were not affected by any of the EALs. There were no significant differences amongst the EALs analysed with respect to the production of EMI.ConclusionsEMI occurred when the EALs were placed close to the tip of the electrode and occasionally when close to the pacemaker; however, no EMI was detected when the EALs were placed near to or 15 cm from the sensing arc in this laboratory experimental model.
Differential responses to predator cues between two mosquito species breeding in different habitats
Authors: OHBA SHIN‐YA , OHTSUKA MASAKAZU , SUNAHARA TOSHIHIKO , SONODA YURI , KAWASHIMA EMIKO , TAKAGI MASAHIRO 
Published: September 2012

1. Natural selection favours females who can correctly assess the predation risk and hence avoid high‐risk oviposition sites and reduce the mortality rate of their offspring. In spite of the potential significance of such behaviour, relatively few studies have assessed the relationship between oviposition behaviour and predation risk.2. The present study aimed to determine the sublethal effects of predators on oviposition site selection by gravid females, the foraging activity of larvae, and the life history traits of two mosquito species that breed in different habitats, Aedes albopictus Skuse (container breeder) and Culex tritaeniorhynchus Giles (wetland breeder).3. Female C. tritaeniorhynchus avoided laying eggs at oviposition sites in the presence of a predator cue. In contrast, female A. albopictus laid eggs in both the absence and presence of the predator cue.4. To examine the effects of predator cues on larval behaviour, experiments were conducted in the absence and presence of a predator cue. Although larval activity was lower in the presence of the predator cue than that in its absence in both species, C. tritaeniorhynchus responded to the predator cue more strongly than A. albopictus. Female A. albopictus that had been reared with caged predators exhibited an extended larval development period, whereas the adult C. tritaeniorhynchus reared in the presence of predators were smaller than those reared in their absence.5. This finding might explain why C. tritaeniorhynchus avoid laying eggs in predator‐conditioned water, for example to increase the fitness of their offspring, but A. albopictus either cannot detect predator cues or are not sensitive to them.
Rachycentron canadum (cobia) Lectin Promoted Mitogenic Response in Mice BALB/c Splenocytes
Authors: Coriolano M. C. , de Melo C. M. L. , Santos A. J. G. , Pereira V. R. A. , Coelho L. C. B. B. 
Published: September 2012

AbstractThe mitogenic lectins are invaluable tools to study the biochemical changes associated with lymphocyte activation and proliferation of various immune cells. Rachycentron canadum lectin (RcaL) was detected and purified from serum of cobia fish. The aim of this study was to evaluate the proliferative response and cytokine production in splenocytes of mice in vitro stimulated with RcaL lectin; Canavalia ensiformis lectin (Con A) was used as positive control. A high proliferation index was induced by RcaL in relation to control cells. Furthermore, RcaL induced higher IL‐2 and IL‐6 production in relation to control. The cell viability was 90% in splenocytes treated with RcaL lectin, but RcaL promoted significant late apoptosis after 24 and 48 h in relation to control. RcaL induced proliferative responses suggesting that this lectin can be used as a mitogenic agent in immunostimulatory assays.