Semi-Empirical Estimation of Velocity Profile for Shallow Gravel Bed Channel

The dependence of flow velocity distribution near the bed on the roughness geometry has led to various approaches for estimating the velocity. Themodels proposed bypreviousstudies aremostlybased on segmented velocityprofiles(e.g., a linear distribution within theinterfacial sublayer and logarithmic distributions above the interfacial sublayer). By increasing number of segments, the possibility of errors in the parameters, as well as constants, are likely to rise. This study assessed the applicability of a hyperbolic tangent function velocity model to estimate double-averaged velocity profile for shallow flow over a rough gravel bed as a single model concept, especially for the area within roughness layer. Velocity profiles over gravel beds with different arrangements and roughness densities from previously published studies using laboratory measurements were used to validate this model. The behaviours of related constants for this model in response to changes in the flow depth and roughness geometry were investigated, and limitations on it application were evaluated. It was found that the constants required to apply hyperbolic tangent function are affected by roughness geometry function and relative submergence. Through this study also observed that HTF is reliable to describe the velocity profile for about twice of geometric roughness height

Thornthwaite-Mather water balance analysis in Tambakbayan watershed, Yogyakarta, Indonesia

Depok sub-district in Yogyakarta is one of the most populous areas, which also develops rapidly. The Tambakbayan watershed, which includes Depok sub-district, has been seen as one crucial watershed in Yogyakarta. This study conducted a Thornthwaite-Mather water balance analysis in the watershed in order to understand its hydrology capability. The result of the study on three stream areas of the watershed (upstream, midstream and downstream) shows that the dry months begins in May- June and ends in September-October. August tends to be the driest month in the year with total deficit value reaches 179.2 mm. Still, the annual rainfall is higher than the annual evapotranspiration. The results also show that the lower area of the watershed has a lower capability to preserve water. However, the watershed still sufficient in providing the domestic water demand in the current state. Comprehensive water management plans suggested to be applied to protect the watershed from overstressing the water resources, especially in the downstream area

Characteristics of claudin expression in follicle-associated epithelium of Peyer's patches: Preferential localization of claudin-4 at the apex of the dome region

Gut-associated lymphoreticular tissue (GALT), such as Peyer's patches (PP) and cecal patches, are important inductive sites for mucosal immune responses. As such, the GALT may have an epithelial barrier different from that of villous epithelium. In this study, we investigated the immunohistochemical distribution of the claudin family and occludin in the follicle-associated epithelium (FAE) of Peyer's patches and cecal patches of murine intestine. Unique profiles of claudin-2, -3, -4 and occludin expression were noted in the tight junctions of the FAE: claudin-4 was preferentially expressed in the apex region; claudin-2 was only weakly expressed on the crypt side of the FAE compared to stronger expression on the crypt side of villous epithelial cells; claudin-3 and occludin were found throughout the dome. These unique expression patterns were present also in cecal patch FAE. We also found that claudin-4 expression in the FAE of Peyer's patches and cecal patches corresponded with the presence of TUNEL-positive apoptotic cells, and Peyer's patch-deficient mice had expression patterns of claudin and occludin in villous epithelia similar to those in wild-type mice. We conclude that claudin-4 expression is preferentially associated with the dome region of FAE, the mucosal inductive site of the murine intestine. In that location and it might correlate with the cell life cycle, help maintain the apex configuration of the dome, or be a factor favoring the uptake of antigens by the FAE

Spectral Lag Relations in GRB Pulses Detected with HETE-2

Using a pulse-fit method, we investigate the spectral lags between the traditional gamma-ray band (50-400 keV) and the X-ray band (6-25 keV) for 8 GRBs with known redshifts (GRB 010921, GRB 020124, GRB 020127, GRB 021211, GRB 030528, GRB 040924, GRB 041006, GRB 050408) detected with the WXM and FREGATE instruments aboard the HETE-2 satellite. We find several relations for the individual GRB pulses between the spectral lag and other observables, such as the luminosity, pulse duration, and peak energy (Epeak). The obtained results are consistent with those for BATSE, indicating that the BATSE correlations are still valid at lower energies (6-25 keV). Furthermore, we find that the photon energy dependence for the spectral lags can reconcile the simple curvature effect model. We discuss the implication of these results from various points of view.Comment: 13 pages, 9 figures, accepted for the publication in PASJ (minor corrections

The ASTRO-H X-ray Observatory

The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the high-energy universe via a suite of four instruments, covering a very wide energy range, from 0.3 keV to 600 keV. These instruments include a high-resolution, high-throughput spectrometer sensitive over 0.3-2 keV with high spectral resolution of Delta E < 7 eV, enabled by a micro-calorimeter array located in the focal plane of thin-foil X-ray optics; hard X-ray imaging spectrometers covering 5-80 keV, located in the focal plane of multilayer-coated, focusing hard X-ray mirrors; a wide-field imaging spectrometer sensitive over 0.4-12 keV, with an X-ray CCD camera in the focal plane of a soft X-ray telescope; and a non-focusing Compton-camera type soft gamma-ray detector, sensitive in the 40-600 keV band. The simultaneous broad bandpass, coupled with high spectral resolution, will enable the pursuit of a wide variety of important science themes.Comment: 22 pages, 17 figures, Proceedings of the SPIE Astronomical Instrumentation "Space Telescopes and Instrumentation 2012: Ultraviolet to Gamma Ray

HETE-2 Observations of the X-Ray Flash XRF 040916

A long X-ray flash was detected and localized by the instruments aboard the High Energy Transient Explorer II (HETE-2) at 00:03:30 UT on 2004 September 16. The position was reported to the GRB Coordinates Network (GCN) approximately 2 hours after the burst. This burst consists of two peaks separated by 200 s, with durations of 110 s and 60 s. We have analyzed the energy spectra of the 1st and 2nd peaks observed with the Wide Field X-Ray Monitor (WXM) and the French Gamma Telescope (FREGATE). We discuss the origin of the 2nd peak in terms of flux variabilities and timescales. We find that it is most likely part of the prompt emission, and is explained by the long-acting engine model. This feature is similar to some bright X-ray flares detected in the early afterglow phase of bursts observed by the Swift satellite.Comment: 9 pages, 4 figures, Accepted for publication in PAS

Hitomi (ASTRO-H) X-ray Astronomy Satellite

The Hitomi (ASTRO-H) mission is the sixth Japanese x-ray astronomy satellite developed by a large international collaboration, including Japan, USA, Canada, and Europe. The mission aimed to provide the highest energy resolution ever achieved at E  >  2  keV, using a microcalorimeter instrument, and to cover a wide energy range spanning four decades in energy from soft x-rays to gamma rays. After a successful launch on February 17, 2016, the spacecraft lost its function on March 26, 2016, but the commissioning phase for about a month provided valuable information on the onboard instruments and the spacecraft system, including astrophysical results obtained from first light observations. The paper describes the Hitomi (ASTRO-H) mission, its capabilities, the initial operation, and the instruments/spacecraft performances confirmed during the commissioning operations for about a month

Spatiotemporal Analysis on the Teleconnection of ENSO and IOD to the Stream Flow Regimes in Java, Indonesia

While many studies on the relationship between climate modes and rainfall in Indonesia already exist, studies targeting climate modes’ relationship to streamflow remain rare. This study applied multiple regression (MR) models with polynomial functions to show the teleconnection from the two prominent climate modes—El Niño–Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD)—to streamflow regimes in eight rivers in Java, Indonesia. Our MR models using data from 1970 to 2018 successfully show that the September–November (SON) season provides the best predictability of the streamflow regimes. It is also found that the predictability in 1970–1989 was better than that in 1999–2018. This suggests that the relationships between the climate modes and streamflow in Java were changed over periods, which is suspected due to the river basin development. Hence, we found no clear spatial distribution patterns of the predictability, suggesting that the effect of ENSO and IOD are similar for the eight rivers. Additionally, the predictability of the high flow index has been found higher than the low flow index. Having elucidated the flow regimes’ predictability by spatiotemporal analysis, this study gives new insight into the teleconnection of ENSO and IOD to the Indonesian streamflow