University of Hawaii at Manoa

About: University of Hawaii at Manoa is a education organization based out in Honolulu, Hawaii, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 13693 authors who have published 25161 publications receiving 1023924 citations.

A Parametric Modeling Approach to Measuring the Gas Masses of Circumstellar Disks

Abstract: The disks that surround young stars are mostly composed of molecular gas, which is harder to detect and interpret than the accompanying dust. Disk mass measurements have therefore relied on large and uncertain extrapolations from the dust to the gas. We have developed a grid of models to study the dependencies of isotopologue CO line strengths on disk structure and temperature parameters and find that a combination of 13CO and C18O observations provides a robust measure of the gas mass. We apply this technique to Submillimeter Array observations of nine circumstellar disks and published measurements of six well studied disks. We find evidence for selective photodissociation of C18O and determine masses to within a factor of about three. The inferred masses for the nine disks in our survey range from 0.7 to 6 M Jup, and all are well below the extrapolation from the interstellar medium gas-to-dust ratio of 100. This is consistent with the low masses of planets found around such stars, and may be due to accretion or photoevaporation of a dust-poor upper atmosphere. However, the masses may be underestimated if there are more efficient CO depletion pathways than those known in molecular clouds and cold cores.

TRPM4 Regulates Calcium Oscillations After T Cell Activation

Abstract: TRPM4 has recently been described as a calcium-activated nonselective (CAN) cation channel that mediates membrane depolarization. However, the functional importance of TRPM4 in the context of calcium (Ca 2+ ) signaling and its effect on cellular responses are not known. Here, the molecular inhibition of endogenous TRPM4 in T cells was shown to suppress TRPM4 currents, with a profound influence on receptor-mediated Ca 2+ mobilization. Agonist-mediated oscillations in intracellular Ca 2+ concentration ([Ca 2+ ] i ), which are driven by store-operated Ca 2+ influx, were transformed into a sustained elevation in [Ca 2+ ] i . This increase in Ca 2+ influx enhanced interleukin-2 production. Thus, TRPM4-mediated depolarization modulates Ca 2+ oscillations, with downstream effects on cytokine production in T lymphocytes.

Role of Narrow Mountains in Large-Scale Organization of Asian Monsoon Convection*

Abstract: The Asian summer monsoon is organized into distinct convection centers, but the mechanism for this organization is not well understood. Analysis of new satellite observations reveals that narrow mountain ranges are an important organizing agent anchoring monsoon convection centers on the windward side. The Bay of Bengal convection, in particular, features the heaviest precipitation on its eastern coast because of orographic lifting as the southwest monsoon impinges on the coastal mountains of Myanmar (also known as Burma). This is in contrast to the widely held view that this convection is centered over the open ocean as implied by coarse-resolution datasets, a view that would require an entirely different explanation for its formation. Narrow in width and modest in height (≤1 km), these mountains are hardly mentioned in conceptual depictions of the large-scale monsoon and poorly represented in global climate models. The numerical simulations of this study show that orographic rainbands are not a...

The hydrology of the humid tropics

Abstract: Hydrological processes in the humid tropics differ from other regions in having greater energy inputs and faster rates of change. In this Review it is argued that understanding of the key hydrological interactions there remains limited, and a vision of future research designed to address these shortcomings is outlined.