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 & Sea surface temperature. The organization has 13693 authors who have published 25161 publications receiving 1023924 citations.

Seismic Wave Propagation in Stratified Media

Abstract: In order to fully appreciate this book, it is necessary to recall some of the recent history of body wave seismology. Until the late 1960s, most of our knowledge of subsurface structure came from travel time studies. Pekeris [1948] and Haskell [1953] had shown how to model seismic data, but existing computers limited the use of their methods to the computation of dispersion curves for simple earth models. Then Helmberger [1968] used the Cagniard-de Hoop method [de Hoop, 1960] to model refraction arrivals and thereby demonstrated the practicality of seismic modeling in the time domain. The Cagniard-de Hoop method is a generalized ray method, which means (in practical terms) that it is good for synthesizing first motions but not so good for the later parts of the seismogram. Accordingly, Fuchs and Muller [1971] returned to the methods of Pekeris and Haskell and showed that with large modern computers, the whole seismogram could be synthesized. However, problems remained, because Haskell matrices are numerically unstable when used to synthesize SV body waves. Methods of overcoming this instability were found (and are still being found), but they are all, with the possible exception of the methods of Schmidt and Tango [1986] and of Chin et al. [1984], complicated, difficult to program, and lacking in physical insight.

Pan-STARRS1 Discovery of Two Ultraluminous Supernovae at z ≈ 0.9

Abstract: We present the discovery of two ultraluminous supernovae (SNe) at z ≈ 0.9 with the Pan-STARRS1 Medium Deep Survey. These SNe, PS1-10ky and PS1-10awh, are among the most luminous SNe ever discovered, comparable to the unusual transients SN 2005ap and SCP 06F6. Like SN 2005ap and SCP 06F6, they show characteristic high luminosities (M_(bol) ≈ –22.5 mag), blue spectra with a few broad absorption lines, and no evidence for H or He. We have constructed a full multi-color light curve sensitive to the peak of the spectral energy distribution in the rest-frame ultraviolet, and we have obtained time series spectroscopy for these SNe. Given the similarities between the SNe, we combine their light curves to estimate a total radiated energy over the course of explosion of (0.9-1.4) × 10^(51) erg. We find photospheric velocities of 12,000-19,000 km s^(–1) with no evidence for deceleration measured across ~3 rest-frame weeks around light curve peak, consistent with the expansion of an optically thick massive shell of material. We show that, consistent with findings for other ultraluminous SNe in this class, radioactive decay is not sufficient to power PS1-10ky, and we discuss two plausible origins for these events: the initial spin-down of a newborn magnetar in a core-collapse SN, or SN shock breakout from the dense circumstellar wind surrounding a Wolf-Rayet star.

Seasonal and interannual variations of the North Equatorial Current bifurcation in a high-resolution OGCM

Abstract: [1] The variation of the North Equatorial Current (NEC) bifurcation is investigated using results from a high-resolution ocean general circulation model (OGCM). The bifurcation occurs at about 15.5°N for the annual average and is easily identifiable in the upper 500 m, but it varies with time and depth. In agreement with recent observations, during the summer season the NEC bifurcation moves equatorward with a weak poleward shift with depth, while a large poleward movement with a poleward shift with depth is found during the winter season. Vertical mode decomposition indicates that the seasonal variation of the NEC bifurcation is dominated by the first two baroclinic modes. On the interannual timescale, the meridional migration of the NEC bifurcation is strongly influenced by El Nino/Southern Oscillation (ENSO); its correlation with the Southern Oscillation Index exceeds 0.8 in magnitude at depths around the thermocline. The NEC bifurcation occurs at its northernmost position during El Nino years and at its southernmost position during La Nina years. This variation is mainly accounted for by westward propagation of upwelling (downwelling) Rossby waves generated by winds in the central equatorial Pacific and by an anomalous anticyclone (cyclone) located in the western North Pacific when a warm (cold) event matures. The interannual variability of the NEC transport is highly correlated with that of the Mindanao Current (MC) and the Kuroshio transports. It is also found that the interannual variability of the NEC bifurcation latitude is highly correlated with the variations of transports in the NEC and the Kuroshio, but is less correlated with transport variations in the MC.

Magnetic resonance spectroscopy to assess neuroinflammation and neuropathic pain

Abstract: Proton magnetic resonance spectroscopy (1H MRS) has been applied to numerous clinical studies, especially for neurological disorders. This technique can non-invasively evaluate brain metabolites and neurochemicals in selected brain regions and is particularly useful for assessing neuroinflammatory disorders. Neurometabolites assessed with MRS include the neuronal markers N-acetylaspartate (NAA) and glutamate (Glu), as well as the glial marker myo-inositol (MI). Therefore, the concentrations of these metabolites typically correspond to disease severity and often correlate well with clinical variables in the various brain disorders. Neuroinflammation with activated astrocytes and microglia in brain disorders are often associated with elevated MI, and to a lesser extent elevated total creatine (tCr) and choline containing compounds (Cho), which are found in higher concentrations in glia than neurons, while neuronal injury is indicated by lower than normal levels of NAA and Glu. This review summarizes the neurometabolite abnormalities found in MRS studies performed in patients with neuroinflammatory disorders or neuropathic pain, which also may be associated with neuroinflammation. These brain disorders include multiple sclerosis, neuroviral infections (including Human Immunodeficiency virus and Hepatitis C), degenerative brain disorders (including Alzheimer’s disease and Parkinson’s disease), stimulant abuse (including methamphetamine and cocaine) as well as several chronic pain syndromes.

Response of inland lake dynamics over the Tibetan Plateau to climate change

Abstract: The water balance of inland lakes on the Tibetan Plateau (TP) involves complex hydrological processes; their dynamics over recent decades is a good indicator of changes in water cycle under rapid global warming. Based on satellite images and extensive field investigations, we demonstrate that a coherent lake growth on the TP interior (TPI) has occurred since the late 1990s in response to a significant global climate change. Closed lakes on the TPI varied heterogeneously during 1976-1999, but expanded coherently and signifi- cantly in both lake area and water depth during 1999-2010. Although the decreased potential evaporation and glacier mass loss may contribute to the lake growth since the late 1990s, the significant water surplus is mainly attributed to increased regional precipitation, which, in turn, may be related to changes in large-scale atmospheric circulation, including the intensified Northern Hemisphere summer monsoon (NHSM) circulation and the poleward shift of the Eastern Asian westerlies jet stream.