167 research outputs found
Distinguishing f(R) theories from general relativity by gravitational lensing effect
The post-Newtonian formulation of a general class of f(R) theories is set up
to 3rd order approximation. It turns out that the information of a specific
form of f(R) gravity is encoded in the Yukawa potential, which is contained in
the perturbative expansion of the metric components. Although the Yukawa
potential is canceled in the 2nd order expression of the effective refraction
index of light, detailed analysis shows that the difference of the lensing
effect between the f(R) gravity and general relativity does appear at the 3rd
order when is larger than the distance to the
gravitational source. However, the difference between these two kinds of
theories will disappear in the axially symmetric spacetime region. Therefore
only in very rare case the f(R) theories are distinguishable from general
relativity by gravitational lensing effect at the 3rd order post-Newtonian
approximation.Comment: 14 page
Invertebrate larval availability during summer upwelling and downwelling on the inner continental shelf off New Jersey
This study examined the effects of wind-driven, cross-shelf circulation on invertebrate larval supply to benthic habitats on the inner continental shelf off Tuckerton, New Jersey, USA. Study sites were located along an inshore/offshore transect in the LEO-15 research area at Beach Haven Ridge, a 12–20 m deep, shore-oblique sand ridge. Meroplankton was sampled using Moored, Automated, Serial Zooplankton Pumps which were programmed to take 250-l samples, ~1 m above the bottom, every 4 h. Upwelling and downwelling conditions were characterized using wind data from the nearby meteorological tower at the Rutgers University Marine Field Station, and bottom temperatures from LEO-15 node data and the pump sites. Studies were carried out during July in 1996 –1998 because previous recruitment studies showed that July was when larval surfclams, Spisula solidissima, were abundant and their settlement maximal. The study was repeated over three years to sample multiple upwelling/downwelling sequences. Although the study focused primarily on the dominant S. solidissima larvae, other meroplankton were also enumerated. Short-lived pulses (12 h or less) of highest larval surfclam concentrations (up to 3000 sample -1, sample volume = 250 l) often coincided with the initial arrival of warm water at the bottom at the initiation of downwelling, indicating a patchy larval distribution that is probably related to high larval concentrations near fronts. On one date in July 1998, very high concentrations of surfclam and pholad bivalve larvae coincided with the arrival of warm, relatively low salinity water. This pattern suggested a larval concentrating mechanism near an estuarine front, perhaps from the Hudson River plume. Sampling during multiple upwelling/downwelling events over the three summers revealed a close correlation between peaks in larval concentration of bivalves and gastropods coinciding with the arrival of downwelled warm water at the bottom at inner shelf sites
A Single-facility Competitive Location Problem in the Plane Based on Customer Choice Rules (CEIBS Working Paper, No. 021/2020/POM/DEC, 2020)
4-(4-Chlorophenyl)-5-(4-nitrophenyl)-3-phenyl-4H-1,2,4-triazole
The title compound, C20H13ClN4O2, was synthesized by the condensation of 4-nitrobenzohydrazide and N-(4-chlorophenyl)benzimidoyl chloride in N,N-dimethylacetamide. The asymmetric unit contains two independent molecules. In one molecule, the triazole ring is oriented at dihedral angles of 23.1 (5), 85.4 (1) and 10.5 (1)° with respect to the phenyl, chlorophenyl and nitrophenyl rings, respectively. In the other molecule, the corresponding dihedral angles are 29.8 (9), 73.4 (7) and 16.4 (3)°
Ketamine Inhibits Lung Fluid Clearance through Reducing Alveolar Sodium Transport
Ketamine is a broadly used anaesthetic for analgosedation. Accumulating clinical evidence shows that ketamine causes pulmonary edema with unknown mechanisms. We measured the effects of ketamine on alveolar fluid clearance in human lung lobes ex vivo. Our results showed that intratracheal instillation of ketamine markedly decreased the reabsorption of 5% bovine serum albumin instillate. In the presence of amiloride (a specific ENaC blocker), fluid resolution was not further decreased, suggesting that ketamine could decrease amiloride-sensitive fraction of AFC associated with ENaC. Moreover, we measured the regulation of amiloride-sensitive currents by ketamine in A549 cells using whole-cell patch clamp mode. Our results suggested that ketamine decreased amiloride-sensitive Na+ currents (ENaC activity) in a dose-dependent fashion. These data demonstrate that reduction in lung ENaC activity and lung fluid clearance following administration of ketamine may be the crucial step of the pathogenesis of resultant pulmonary edema
Coverage Analysis for Cellular-Connected Random 3D Mobile UAVs with Directional Antennas
This letter proposes an analytical framework to evaluate the coverage
performance of a cellular-connected unmanned aerial vehicle (UAV) network in
which UAV user equipments (UAV-UEs) are equipped with directional antennas and
move according to a three-dimensional (3D) mobility model. The ground base
stations (GBSs) equipped with practical down-tilted antennas are distributed
according to a Poisson point process (PPP). With tools from stochastic
geometry, we derive the handover probability and coverage probability of a
random UAV-UE under the strongest average received signal strength (RSS)
association strategy. The proposed analytical framework allows to investigate
the effect of UAV-UE antenna beamwidth, mobility speed, cell association, and
vertical motions on both the handover probability and coverage probability. We
conclude that the optimal UAV-UE antenna beamwidth decreases with the GBS
density, and the omnidirectional antenna model is preferred in the sparse
network scenario. What's more, the superiority of the strongest average RSS
association over the nearest association diminishes with the increment of GBS
density.Comment: 5 pages, 5 figures, submitted to IEEE Wireless Communications Letter
Low Expression of miR-448 Induces EMT and Promotes Invasion by Regulating ROCK2 in Hepatocellular Carcinoma
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