610 research outputs found
Low-ionization Line Emission from Starburst Galaxies: A New Probe of Galactic-Scale Outflows
We study the kinematically narrow, low-ionization line emission from a
bright, starburst galaxy at z = 0.69 using slit spectroscopy obtained with
Keck/LRIS. The spectrum reveals strong absorption in MgII and FeII resonance
transitions with Doppler shifts of -200 to -300 km/s, indicating a cool gas
outflow. Emission in MgII near and redward of systemic velocity, in concert
with the observed absorption, yields a P Cygni-like line profile similar to
those observed in the Ly alpha transition in Lyman Break Galaxies. Further, the
MgII emission is spatially resolved, and extends significantly beyond the
emission from stars and HII regions within the galaxy. Assuming the emission
has a simple, symmetric surface brightness profile, we find that the gas
extends to distances > ~7 kpc. We also detect several narrow FeII*
fine-structure lines in emission near the systemic velocity, arising from
energy levels which are radiatively excited directly from the ground state. We
suggest that the MgII and FeII* emission is generated by photon scattering in
the observed outflow, and emphasize that this emission is a generic prediction
of outflows. These observations provide the first direct constraints on the
minimum spatial extent and morphology of the wind from a distant galaxy.
Estimates of these parameters are crucial for understanding the impact of
outflows in driving galaxy evolution.Comment: Submitted to ApJL. 6 pages, 4 figures. Uses emulateapj forma
Mutations in SPG11, encoding spatacsin, are a major cause of spastic paraplegia with thin corpus callosum.
Autosomal recessive hereditary spastic paraplegia (ARHSP) with thin corpus
callosum (TCC) is a common and clinically distinct form of familial spastic
paraplegia that is linked to the SPG11 locus on chromosome 15 in most affected
families. We analyzed 12 ARHSP-TCC families, refined the SPG11 candidate interval
and identified ten mutations in a previously unidentified gene expressed
ubiquitously in the nervous system but most prominently in the cerebellum,
cerebral cortex, hippocampus and pineal gland. The mutations were either nonsense
or insertions and deletions leading to a frameshift, suggesting a
loss-of-function mechanism. The identification of the function of the gene will
provide insight into the mechanisms leading to the degeneration of the
corticospinal tract and other brain structures in this frequent form of ARHSP
Detectors and cryostat design for the SuMIRe Prime Focus Spectrograph (PFS)
We describe the conceptual design of the camera cryostats, detectors, and
detector readout electronics for the SuMIRe Prime Focus Spectrograph (PFS)
being developed for the Subaru telescope. The SuMIRe PFS will consist of four
identical spectrographs, each receiving 600 fibers from a 2400 fiber robotic
positioner at the prime focus. Each spectrograph will have three channels
covering wavelength ranges 3800 {\AA} - 6700 {\AA}, 6500 {\AA} - 10000 {\AA},
and 9700 {\AA} - 13000 {\AA}, with the dispersed light being imaged in each
channel by a f/1.10 vacuum Schmidt camera. In the blue and red channels a pair
of Hamamatsu 2K x 4K edge-buttable CCDs with 15 um pixels are used to form a 4K
x 4K array. For the IR channel, the new Teledyne 4K x 4K, 15 um pixel,
mercury-cadmium-telluride sensor with substrate removed for short-wavelength
response and a 1.7 um cutoff will be used. Identical detector geometry and a
nearly identical optical design allow for a common cryostat design with the
only notable difference being the need for a cold radiation shield in the IR
camera to mitigate thermal background. This paper describes the details of the
cryostat design and cooling scheme, relevant thermal considerations and
analysis, and discusses the detectors and detector readout electronics
Reduced Na+ and higher K+ channel expression and function contribute to right ventricular origin of arrhythmias in Scn5a+/− mice
Brugada syndrome (BrS) is associated with ventricular tachycardia originating particularly in the right ventricle (RV). We explore electrophysiological features predisposing to such arrhythmic tendency and their possible RV localization in a heterozygotic Scn5a+/− murine model. Nav1.5 mRNA and protein expression were lower in Scn5a+/− than wild-type (WT), with a further reduction in the RV compared with the left ventricle (LV). RVs showed higher expression levels of Kv4.2, Kv4.3 and KChIP2 in both Scn5a+/− and WT. Action potential upstroke velocity and maximum Na+ current (INa) density were correspondingly decreased in Scn5a+/−, with a further reduction in the RV. The voltage dependence of inactivation was shifted to more negative values in Scn5a+/−. These findings are predictive of a localized depolarization abnormality leading to slowed conduction. Persistent Na+ current (IpNa) density was decreased in a similar pattern to INa. RV transient outward current (Ito) density was greater than LV in both WT and Scn5a+/−, and had larger time constants of inactivation. These findings were also consistent with the observation that AP durations were smallest in the RV of Scn5a+/−, fulfilling predictions of an increased heterogeneity of repolarization as an additional possible electrophysiological mechanism for arrhythmogenesis in BrS
Generation of degenerate, factorizable, pulsed squeezed light at telecom wavelengths
We characterize a periodically poled KTP crystal that produces an entangled,
two-mode, squeezed state with orthogonal polarizations, nearly identical,
factorizable frequency modes, and few photons in unwanted frequency modes. We
focus the pump beam to create a nearly circular joint spectral probability
distribution between the two modes. After disentangling the two modes, we
observe Hong-Ou-Mandel interference with a raw (background corrected)
visibility of 86 % (95 %) when an 8.6 nm bandwidth spectral filter is applied.
We measure second order photon correlations of the entangled and disentangled
squeezed states with both superconducting nanowire single-photon detectors and
photon-number-resolving transition-edge sensors. Both methods agree and verify
that the detected modes contain the desired photon number distributions
Novel TRPM8 Antagonist Attenuates Cold Hypersensitivity after Peripheral Nerve Injury in Rats
Safety and EEG data quality of concurrent high-density EEG and high-speed fMRI at 3 Tesla
Concurrent EEG and fMRI is increasingly used to characterize the spatial-temporal dynamics of brain activity. However, most studies to date have been limited to conventional echo-planar imaging (EPI). There is considerable interest in integrating recently developed high-speed fMRI methods with high-density EEG to increase temporal resolution and sensitivity for task-based and resting state fMRI, and for detecting interictal spikes in epilepsy. In the present study using concurrent high-density EEG and recently developed high-speed fMRI methods, we investigate safety of radiofrequency (RF) related heating, the effect of EEG on cortical signal-to-noise ratio (SNR) in fMRI, and assess EEG data quality.The study compared EPI, multi-echo EPI, multi-band EPI and multi-slab echo-volumar imaging pulse sequences, using clinical 3 Tesla MR scanners from two different vendors that were equipped with 64- and 256-channel MR-compatible EEG systems, respectively, and receive only array head coils. Data were collected in 11 healthy controls (3 males, age range 18-70 years) and 13 patients with epilepsy (8 males, age range 21-67 years). Three of the healthy controls were scanned with the 256-channel EEG system, the other subjects were scanned with the 64-channel EEG system. Scalp surface temperature, SNR in occipital cortex and head movement were measured with and without the EEG cap. The degree of artifacts and the ability to identify background activity was assessed by visual analysis by a trained expert in the 64 channel EEG data (7 healthy controls, 13 patients).RF induced heating at the surface of the EEG electrodes during a 30-minute scan period with stable temperature prior to scanning did not exceed 1.0° C with either EEG system and any of the pulse sequences used in this study. There was no significant decrease in cortical SNR due to the presence of the EEG cap (p > 0.05). No significant differences in the visually analyzed EEG data quality were found between EEG recorded during high-speed fMRI and during conventional EPI (p = 0.78). Residual ballistocardiographic artifacts resulted in 58% of EEG data being rated as poor quality.This study demonstrates that high-density EEG can be safely implemented in conjunction with high-speed fMRI and that high-speed fMRI does not adversely affect EEG data quality. However, the deterioration of the EEG quality due to residual ballistocardiographic artifacts remains a significant constraint for routine clinical applications of concurrent EEG-fMRI
Predicting Treatment Outcome in Major Depressive Disorder Using Serotonin 4 Receptor PET Brain Imaging, Functional MRI, Cognitive-, EEG-Based, and Peripheral Biomarkers:A NeuroPharm Open Label Clinical Trial Protocol
Measurement of Muon Neutrino Quasi-Elastic Scattering on Carbon
The observation of neutrino oscillations is clear evidence for physics beyond
the standard model. To make precise measurements of this phenomenon, neutrino
oscillation experiments, including MiniBooNE, require an accurate description
of neutrino charged current quasi-elastic (CCQE) cross sections to predict
signal samples. Using a high-statistics sample of muon neutrino CCQE events,
MiniBooNE finds that a simple Fermi gas model, with appropriate adjustments,
accurately characterizes the CCQE events observed in a carbon-based detector.
The extracted parameters include an effective axial mass, M_A^eff = 1.23+/-0.20
GeV, that describes the four-momentum dependence of the axial-vector form
factor of the nucleon; and a Pauli-suppression parameter, kappa =
1.019+/-0.011. Such a modified Fermi gas model may also be used by future
accelerator-based experiments measuring neutrino oscillations on nuclear
targets.Comment: 5 pages, 3 figure
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GateFinder: projection-based gating strategy optimization for flow and mass cytometry
Motivation: High-parameter single-cell technologies can reveal novel cell populations of interest, but studying or validating these populations using lower-parameter methods remains challenging.Results: Here, we present GateFinder, an algorithm that enriches high-dimensional cell types with simple, stepwise polygon gates requiring only two markers at a time. A series of case studies of complex cell types illustrates how simplified enrichment strategies can enable more efficient assays, reveal novel biomarkers and clarify underlying biology
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