An upper mass limit for the progenitor of the Type II-P supernova SN 1999gi

Masses and progenitor evolutionary states of Type II supernovae remain almost unconstrained by direct observations. Only one robust observation of a progenitor (SN 1987A) and one plausible observation (SN 1993J) are available. Neither matched theoretical predictions, and in this Letter we report limits on a third progenitor (SN 1999gi). The Hubble Space Telescope (HST) has imaged the site of the Type II-P supernova SN 1999gi with the Wide Field Planetary Camera 2 (WFPC2) in two filters (F606W and F300W) prior to explosion. The distance to the host galaxy (NGC 3184) of 7.9 Mpc means that the most luminous, massive stars are resolved as single objects in the archive images. The supernova occurred in a resolved, young OB association 2.3 kpc from the center of NGC 3184 with an association age of about 4 Myr. Follow-up images of SN 1999gi with WFPC2 taken 14 months after discovery determine the precise position of the supernova on the preexplosion frames. An upper limit of the absolute magnitude of the progenitor is estimated (M-v greater than or equal to -5.1). By comparison with stellar evolutionary tracks, this can be interpreted as a stellar mass, and we determine an upper mass limit of 9(-2)(+3) M.. We discuss the possibility of determining the masses or mass limits for numerous nearby core-collapse supernovae using the HST archive enhanced by our current SNAP program.

Vision Modulates Corticospinal Suppression in a Functionally Specific Manner during Movement of the Opposite Limb

The effect of vision on the excitability of corticospinal projections to the flexor carpi radialis (FCR) and extensor carpi radialis (ECR) muscles of right human forearm was investigated before and during discrete movement of the opposite limb. An external force opposed the initial phase of the movement (wrist flexion) and assisted the reverse phase, so that recruitment of the wrist extensors was minimized. Three conditions were used as follows: viewing the inactive right limb (Vision), viewing the mirror image of the moving left limb (Mirror), and with vision of the right limb occluded (No Vision). Transcranial magnetic stimulation was delivered to the left motor cortex: before, at the onset of, or during the left limb movement to obtain motor evoked potentials (MEPs) in the muscles of the right forearm. At and following movement onset, MEPs obtained in the right FCR were smaller in the Vision condition than in the Mirror and No Vision conditions. A distinct pattern of variation was obtained for the ECR. In all conditions, MEPs in this muscle were elevated upon or following movement of the opposite limb. An additional analysis of ipsilateral silent periods indicated that interhemispheric inhibition plays a role in mediating these effects. Activity-dependent changes in corticospinal output to a resting limb during discrete actions of the opposite limb are thus directly contingent upon where one looks. Furthermore, the extent to which vision exerts an influence upon projections to specific muscles varies in accordance with the functional contribution of their homologs to the intended action.

Differences in the diagnostic yield of upper gastrointestinal endoscopy in dyspeptic patients receiving proton-pump inhibitors and H2-receptor antagonists

Patients attending for diagnostic oesophagogastroduodenoscopy (OGD) for dyspeptic symptoms are often receiving acid-suppression therapy that has not been discontinued prior to endoscopy, and this may reduce the diagnostic yield of endoscopy. The aim of this study was to compare the diagnostic yield of OGD in uncomplicated dyspepsia in patients receiving no medication, those receiving acid-suppression therapy, and those receiving nonsteroidal anti-inflammatory drugs (NSAIDs) at the time of endoscopy.

An audit of hospital admissions for acute upper gastrointestinal haemorrhage

A retrospective survey was made of all 189 patients admitted with acute upper gastrointestinal haemorrhage to the Belfast City Hospital in one year. The commonest single reason for admission was peptic ulcer disease, but this was lower than in other published series from the United Kingdom. Overall mortality was 4.8%. The majority of patients did not require either blood transfusion or surgery. There may be potential benefits of endoscopic haemostatic techniques to deal with this condition.

On the filling factor of emitting material in the upper atmosphere of ε Eri (K2 V)

The emission measure distribution in the upper transition region and corona of e Eri is derived from observed emission-line fluxes. Theoretical emission measure distributions are calculated assuming that the radiation losses are balanced by the net conductive flux. We discuss how the area factor of the emitting regions as a function of temperature can be derived from a comparison between these emission measure distributions. It is found that the filling factor varies from ~0.2 in the mid-transition region to ~1.0 in the inner corona. The sensitivity of these results to the adopted ion fractions, the iron abundance and other parameters is discussed. The area factors found are qualitatively similar to the observed structure of the solar atmosphere, and can be used to constrain two-component models of the chromosphere. Given further observations, the method could be applied to investigate the trends in filling factors with indicators of stellar activity.

Human pose tracking in low dimensional space enhanced by limb correction

This paper proposes a two-level 3D human pose tracking method for a specific action captured by several cameras. The generation of pose estimates relies on fitting a 3D articulated model on a Visual Hull generated from the input images. First, an initial pose estimate is constrained by a low dimensional manifold learnt by Temporal Laplacian Eigenmaps. Then, an improved global pose is calculated by refining individual limb poses. The validation of our method uses a public standard dataset and demonstrates its accurate and computational efficiency. © 2011 IEEE.

Relative Respiratory Syncytial Virus Cytopathogenesis in Upper and Lower Respiratory Tract Epithelium

Respiratory syncytial virus (RSV) is a major pathogen that primarily infects airway epithelium. Most infants suffer mild upper respiratory tract (URT) symptoms, while approximately one third progress to lower respiratory tract (LRT) involvement. Despite the ubiquity of URT infection, little is known about the relative cytopathogenesis of RSV infection in infant URT and LRT.

Observations of ubiquitous compressive waves in the Sun's chromosphere

The details of the mechanism(s) responsible for the observed heating and dynamics of the solar atmosphere still remain a mystery. Magnetohydrodynamic waves are thought to have a vital role in this process. Although it has been shown that incompressible waves are ubiquitous in off-limb solar atmospheric observations, their energy cannot be readily dissipated. Here we provide, for the first time, on-disk observation and identification of concurrent magnetohydrodynamic wave modes, both compressible and incompressible, in the solar chromosphere. The observed ubiquity and estimated energy flux associated with the detected magnetohydrodynamic waves suggest the chromosphere is a vast reservoir of wave energy with the potential to meet chromospheric and coronal heating requirements. We are also able to propose an upper bound on the flux of the observed wave energy that is able to reach the corona based on observational constraints, which has important implications for the suggested mechanism(s) for quiescent coronal heating. © 2012 Macmillan Publishers Limited. All rights reserved.

A new radiocarbon chronology of Baumkirchen, stratotype for the onset of the Upper Wurmian in the Alps

ABSTRACT

The start of the Upper Wurmian in the Alps was marked by massive fluvioglacial aggradation prior to the arrival of the Central Alpine glaciers. In 1984, the Subcommission on European Quaternary Stratigraphy defined the clay pit of Baumkirchen (in the foreland of the Inn Valley, Austria) as the stratotype for the Middle to Upper Wurmian boundary in the Alps. Key for the selection of this site was its radiocarbon chronology, which still ranks among the most important datasets of this time interval in the Alps. In this study we re-sampled all available original plant specimens and established an accelerator mass spectrometry chronology which supersedes the published 40-year-old chronology. The new data show a much smaller scatter and yielded slightly older conventional radiocarbon dates clustering at ca. 31 C-14 ka BP. When calibrated using INTCAL13 the new data suggest that the sampled interval of 653-681 m in the clay pit was deposited 34-36 cal ka BP. Using two new radiocarbon dates of bone fragments found in the fluvioglacial gravel above the banded clays allows us to constrain the timing of the marked change from lacustrine to fluvioglacial sedimentation to ca. 32-33 cal ka BP, which suggests a possible link to the Heinrich 3 event in the North Atlantic. Copyright (c) 2013 John Wiley & Sons, Ltd.