We present the discovery of seven quasars at z > 5.7, selected from ~2000 deg2 of multicolor imaging data of the Sloan Digital Sky Survey. The new quasars have redshifts z from 5.79 to 6.13. Five are ...selected as part of a complete flux-limited sample in the SDSS northern Galactic cap; two have larger photometric errors and are not part of the complete sample. One of the new quasars, SDSS J1335+3533 (z = 5.93), exhibits no emission lines; the 3 s limit on the rest-frame equivalent width of the Lya+N V line is 5 A. It is the highest redshift lineless quasar known and could be a gravitational lensed galaxy, a BL Lac object, or a new type of quasar. Two new z > 6 quasars, SDSS 1250+3130 (z = 6.13) and SDSS J1137+3549 (z = 6.01), show deep Gunn-Peterson absorption gaps in Lya. These gaps are narrower than the complete Gunn-Peterson absorption troughs observed among quasars at z > 6.2 and do not have complete Lyb absorption.
Pivotal to brain development and function is an intact blood-brain barrier (BBB), which acts as a gatekeeper to control the passage and exchange of molecules and nutrients between the circulatory ...system and the brain parenchyma. The BBB also ensures homeostasis of the central nervous system (CNS). We report that germ-free mice, beginning with intrauterine life, displayed increased BBB permeability compared to pathogen-free mice with a normal gut flora. The increased BBB permeability was maintained in germ-free mice after birth and during adulthood and was associated with reduced expression of the tight junction proteins occludin and claudin-5, which are known to regulate barrier function in endothelial tissues. Exposure of germ-free adult mice to a pathogen-free gut microbiota decreased BBB permeability and up-regulated the expression of tight junction proteins. Our results suggest that gut microbiota-BBB communication is initiated during gestation and propagated throughout life.
•Optical flow accurately measured vibrations 450 times smaller than a pixel.•Optimal processing parameters must be chosen to obtain accurate results.•A systematic method of determining the parameter ...values should be researched.
As digital cameras become cheaper and faster, new opportunities for measuring structural vibration are unlocked. Measuring vibration through video sequences can provide full field measurements of a structure’s motion. Digital image correlation is an established method for measuring structural vibration but requires visual surface preparation of the object being measured. Recently, a new method based on optical flow analysis of video sequences has surfaced that can measure structural vibration without any surface preparation whatsoever. This article presents an experiment to test the accuracy of the new method. The accuracy of the technique is evaluated for several sub-pixel vibration displacement amplitudes. The response is measured by an accelerometer, a laser vibrometer and marker tracking and compared to the optical flow method’s results. The results obtained indicate that it is possible to measure vibration amplitudes 450 times smaller than a single image pixel accurately.
In the heart, adenosine binds to pharmacologically distinct G-protein-coupled receptors (A sub(1)-R, A sub(2A)-R, and A sub(3)-R). While the role of A sub(1)-and A sub(3)-Rs in the heart has been ...clarified, the effect of genetically manipulating the A sub(2A)-R has not been defined. Thus, we created mice overexpressing a cardiac-restricted A sub(2A)-R transgene. Mice with both low (Lo) and high (Hi) levels of A sub(2A)-R overexpression demonstrated an increase in cardiac contractility at 12 weeks. These changes were associated with a significantly higher systolic but not diastolic Ca super(2+) super(i), higher maximal contraction amplitudes, and a significantly enhanced sarcoplasmic reticulum Ca super(2+) uptake activity. At 20 weeks, the effects of A sub(2A)-R overexpression on cardiac contractility diminished. The positive effects elicited by A sub(2A)-R overexpression differ from the heart failure phenotype we observed with A sub(1)-R overexpresson. Interestingly, coexpression of A sub(2A)-R TG sub(Hi), but not A sub(2A)-R TGLo, enhanced survival, prevented the development of left ventricular dysfunction and heart failure, and improved Ca super(2+) handling in mice overexpressing the A sub(1)-R. These results suggest that adenosine-mediated signaling in the heart requires a balance between A sub(1)- and A sub(2A)-Rs--a finding that may have important implications for the ongoing clinical evaluation of adenosine receptor subtype-specific agonists and antagonists for the treatment of cardiovascular diseases.
•The shaft Instantaneous Angular Position (IAP) is calculated using a State Space Model.•More accurate answers are obtained using the IAP for transient conditions.•Tip deflection accuracy is ...dependant on blade circumferential location.•A new validation approach for BTT tip deflections is presented.
Rotor blade condition monitoring is considered an important aspect of turbomachine management, especially with the current trend of systems operating at higher speeds, loads and temperatures. Blade Tip Timing is a non-intrusive method of performing rotor blade condition monitoring during turbomachine operation. The technique uses sensors embedded into the turbomachine casing in conjunction with a shaft encoder. A BTT system calculates the difference between the true and expected Angle of Arrival (AoA) of each blade at each sensor. This difference can be used in many ways to perform diagnostics. When calculating the AoA, the shaft speed within each revolution is often assumed as constant. This assumption is incorrect for transient conditions such as a run-up. The incorrect assumption leads to errors in the calculated AoAs. This article proposes a more accurate method for calculating the AoA. A state space equation for the shaft Instantaneous Angular Speed and Instantaneous Angular Position is derived and solved using a Kalman filter. The proposed method is validated using laboratory and field tests.
A wide spectrum of clinical manifestations has become a hallmark of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) COVID-19 pandemic, although the immunological underpinnings of ...diverse disease outcomes remain to be defined. We performed detailed characterization of B cell responses through high-dimensional flow cytometry to reveal substantial heterogeneity in both effector and immature populations. More notably, critically ill patients displayed hallmarks of extrafollicular B cell activation and shared B cell repertoire features previously described in autoimmune settings. Extrafollicular activation correlated strongly with large antibody-secreting cell expansion and early production of high concentrations of SARS-CoV-2-specific neutralizing antibodies. Yet, these patients had severe disease with elevated inflammatory biomarkers, multiorgan failure and death. Overall, these findings strongly suggest a pathogenic role for immune activation in subsets of patients with COVID-19. Our study provides further evidence that targeted immunomodulatory therapy may be beneficial in specific patient subpopulations and can be informed by careful immune profiling.
Electrostatic charging affects the many-body spectrum of Andreev states, yet its influence on their microwave properties has not been elucidated. We developed a circuit quantum electrodynamics probe ...that, in addition to transition spectroscopy, measures the microwave susceptibility of different states of a semiconductor nanowire weak link with a single dominant (spin-degenerate) Andreev level. We found that the microwave susceptibility does not exhibit a particle-hole symmetry, which we qualitatively explain as an influence of Coulomb interaction. Moreover, our state-selective measurement reveals a large, π-phase shifted contribution to the response common to all many-body states which can be interpreted as arising from a phase-dependent continuum in the superconducting density of states.
Abstract
We present photometric and spectroscopic observations of the 03fg-like Type Ia supernova (SN Ia) ASASSN-15hy from the ultraviolet (UV) to the near-infrared (NIR). ASASSN-15hy shares many of ...the hallmark characteristics of 03fg-like SNe Ia, previously referred to as “super-Chandrasekhar” SNe Ia. It is bright in the UV and NIR, lacks a clear
i
-band secondary maximum, shows a strong and persistent C
ii
feature, and has a low Si
ii
λ
6355 velocity. However, some of its properties are also extreme among the subgroup. ASASSN-15hy is underluminous (
M
B
,peak
=
−
19.14
−
0.16
+
0.11
mag), red (
(
B
−
V
)
B
max
=
0.18
−
0.03
+
0.01
mag), yet slowly declining (Δ
m
15
(
B
) = 0.72 ± 0.04 mag). It has the most delayed onset of the
i
-band maximum of any 03fg-like SN. ASASSN-15hy lacks the prominent
H
-band break emission feature that is typically present during the first month past maximum in normal SNe Ia. Such events may be a potential problem for high-redshift SN Ia cosmology. ASASSN-15hy may be explained in the context of an explosion of a degenerate core inside a nondegenerate envelope. The explosion impacting the nondegenerate envelope with a large mass provides additional luminosity and low ejecta velocities. An initial deflagration burning phase is critical in reproducing the low
56
Ni mass and luminosity, while the large core mass is essential in providing the large diffusion timescales required to produce the broad light curves. The model consists of a rapidly rotating 1.47
M
⊙
degenerate core and a 0.8
M
⊙
nondegenerate envelope. This “deflagration core-degenerate” scenario may result from the merger between a white dwarf and the degenerate core of an asymptotic giant branch star.
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