Showing papers by "University of Hawaii at Manoa published in 2000"

Pacific–East Asian Teleconnection: How Does ENSO Affect East Asian Climate?

Abstract: Observational evidence is presented to show a teleconnection between the central Pacific and East Asia during the extreme phases of ENSO cycles. This Pacific‐East Asian teleconnection is confined to the lower troposphere. The key system that bridges the warm (cold) events in the eastern Pacific and the weak (strong) East Asian winter monsoons is an anomalous lower-tropospheric anticyclone (cyclone) located in the western North Pacific. The western North Pacific wind anomalies develop rapidly in late fall of the year when a strong warm or cold event matures. The anomalies persist until the following spring or early summer, causing anomalously wet (dry) conditions along the East Asian polar front stretching from southern China northeastward to the east of Japan (Kuroshio extension). Using atmospheric general circulation and intermediate models, the authors show that the anomalous Philippine Sea anticyclone results from a Rossby-wave response to suppressed convective heating, which is induced by both the in situ ocean surface cooling and the subsidence forced remotely by the central Pacific warming. The development of the anticyclone is nearly concurrent with the enhancement of the local sea surface cooling. Both the anticyclone and the cooling region propagate slowly eastward. The development and persistence of the teleconnection is primarily attributed to a positive thermodynamic feedback between the anticyclone and the sea surface cooling in the presence of mean northeasterly trades. The rapid establishment of the Philippine Sea wind and SST anomalies implies the occurrence of extratropical‐tropical interactions through cold surge‐induced exchanges of surface buoyancy flux. The central Pacific warming plays an essential role in the development of the western Pacific cooling and the wind anomalies by setting up a favorable environment for the anticyclone‐ SST interaction and midlatitude‐tropical interaction in the western North Pacific.

Evidence that decomposition rates of organic carbon in mineral soil do not vary with temperature.

Abstract: It has been suggested that increases in temperature can accelerate the decomposition of organic carbon contained in forest mineral soil (Cs), and, therefore, that global warming should increase the release of soil organic carbon to the atmosphere1,2,3,4,5,6. These predictions assume, however, that decay constants can be accurately derived from short-term laboratory incubations of soil or that in situ incubations of fresh litter accurately represent the temperature sensitivity of Cs decomposition. But our limited understanding of the biophysical factors that control Cs decomposition rates, and observations of only minor increases in Cs decomposition rate with temperature in longer-term forest soil heating experiments7,8,9,10,11,12 and in latitudinal comparisons of Cs decomposition rates13,14,15 bring these predictions into question. Here we have compiled Cs decomposition data from 82 sites on five continents. We found that Cs decomposition rates were remarkably constant across a global-scale gradient in mean annual temperature. These data suggest that Cs decomposition rates for forest soils are not controlled by temperature limitations to microbial activity, and that increased temperature alone will not stimulate the decomposition of forest-derived carbon in mineral soil.

Temperature effects on export production in the open ocean

Abstract: A pelagic food web model was formulated with the goal of developing a quantitative understanding of the relationship between total production, export production, and environmental variables in marine ecosystems. The model assumes that primary production is partitioned through both large and small phytoplankton and that the food web adjusts to changes in the rate of allochthonous nutrient inputs in a way that maximizes stability, i.e., the ability of the system to return to steady state following a perturbation. The results of the modeling exercise indicate that ef ratios, defined as new production/total production = export production/total production, are relatively insensitive to total production rates at temperatures greater than ∼25°C and lie in the range 0.1-0.2. At moderate to high total production rates, ef ratios are insensitive to total production and negatively correlated with temperature. The maximum ef ratios are ∼0.67 at high rates of production and temperatures of 0°−10°C. At temperatures less than ∼20°C, there is a transition from low ef ratios to relatively high ef ratios as total production increases from low to moderate values. This transition accounts for the hyperbolic relationship often presumed to exist between ef ratios and total production. At low rates of production the model predicts a negative correlation between production and ef ratios, a result consistent with data collected at station ALOHA (22°45′N, 158°W) in the North Pacific subtropical gyre. The predictions of the model are in excellent agreement with results reported from the Joint Global Ocean Flux Study (JGOFS) and from other field work. In these studies, there is virtually no correlation between total production and ef ratios, but temperature alone accounts for 86% of the variance in the ef ratios. Model predictions of the absolute and relative abundance of autotrophic and heterotrophic microorganisms are in excellent agreement with data reported from field studies. Combining the ef ratio model with estimates of ocean temperature and photosynthetic rates derived from satellite data indicates that export production on a global scale is ∼20% of net photosynthesis. The results of the model have important implications for the impact of climate change on export production, particularly with respect to temperature effects.

Tau neutrinos favored over sterile neutrinos in atmospheric muon neutrino oscillations.

Abstract: The previously published atmospheric neutrino data did not distinguish whether muon neutrinos were oscillating into tau neutrinos or sterile neutrinos, as both hypotheses fit the data. Using data recorded in 1100 live days of the Super-Kamiokande detector, we use three complementary data samples to study the difference in zenith angle distribution due to neutral currents and matter effects. We find no evidence favoring sterile neutrinos, and reject the hypothesis at the $99%$ confidence level. On the other hand, we find that oscillation between muon and tau neutrinos suffices to explain all the results in hand.

The Detection of Dementia in the Primary Care Setting

Abstract: Background Recognition and medical record documentation of dementia in the primary care setting are thought to be poor. To our knowledge, previous studies have not examined these issues in private practice office settings within the United States. Objective To determine the rate of unrecognized and undocumented dementia in a primary care internal medicine private practice. Methods This was a cross-sectional study of 297 ambulatory persons aged 65 years and older attending an internal medicine private group practice within an Asian American community of Honolulu, Hawaii. Of the subjects, 95% had been with their current primary care physician for at least 1 year. Each subject's primary care physician noted the presence or absence of dementia by questionnaire at the time of an office visit. An investigating physician (V.G.V.) subsequently assessed cognitive function using the Cognitive Abilities Screening Instrument, and confirmed the presence of dementia and its severity, if present, using Benson and Cummings' criteria and the Clinical Dementia Rating Scale, respectively. A trained research assistant completed telephone interviews to proxy informants for collateral information concerning cognition, behavior, and occupational or social function. Subjects' outpatient medical records were reviewed for documentation of problems with cognition. Results Twenty-six cases of dementia were identified. Of these 26, 17 (65%) (95% confidence interval, 44.3-82.8) were not documented in outpatient medical records; of 18 patients, 12 (67%) (95% confidence interval, 40.9-86.7) were not thought to have dementia by their physicians at the time of the office visit. Recognition and documentation rates increased with advancing stage of disease. Conclusion Dementia is often unrecognized and undocumented in private practice settings.

Interdecadal Change of the Structure of the ENSO Mode and Its Impact on the ENSO Frequency

Abstract: In the late 1970s, the ENSO cycle exhibited frequency change. The oscillation period increased from 2–4 yr (high frequency) during 1962–75 to 4–6 yr (low frequency) during 1980–93. Observations suggest that this frequency change was accompanied by a significant change in the structure of the coupled ENSO mode. In comparison with the high-frequency regime, the structure of the coupled mode in the low-frequency regime shows three distinctive features during the warm phase of ENSO: the eastward shift of the westerly anomalies, the meridional expansion of the westerly anomalies, and the weaker intensity of the easterly anomalies in the eastern Pacific. To test the robustness of the relationship between the oscillation period and the structure of the coupled mode, the authors designed empirical atmospheric models based on observations and coupled them with the ocean model of Zebiak and Cane. Numerical experiments demonstrate that the ENSO period is sensitive to changes in the wind anomaly pattern in a...

Upper-Layer Circulation in the South China Sea

Abstract: Upper-layer circulation is investigated by using all available historical temperature profiles combined with climatological temperature–salinity relationships in the South China Sea. Two cyclonic eddies are revealed: one is located east of Vietnam (called the East Vietnam eddy) and the other is off northwest Luzon (called the West Luzon eddy). Both local Ekman pumping and remotely forced basin-scale circulation are important mechanisms controlling these two eddies. The Luzon Strait transport (relative to 400 db) is estimated to be of the order 3.0 Sv (1 Sv = 1 × 106 m3 s−1) in the mean, and has a seasonal cycle dominated by the annual signal, with a maximum (5.3 Sv) in January–February and a minimum (0.2 Sv) in June–July. Pressure gradients are also examined to explore the dynamics of the intrusion of waters from the Pacific into the South China Sea through the Luzon Strait.

Association of vitamin E and C supplement use with cognitive function and dementia in elderly men

Abstract: Objective: To determine whether use of vitamin E and C supplements protects against subsequent development of dementia and poor cognitive functioning. Methods: The Honolulu–Asia Aging Study is a longitudinal study of Japanese-American men living in Hawaii. Data for this study were obtained from a subsample of the cohort interviewed in 1982, and from the entire cohort from a mailed questionnaire in 1988 and the dementia prevalence survey in 1991 to 1993. The subjects included 3,385 men, age 71 to 93 years, whose use of vitamin E and C supplements had been ascertained previously. Cognitive performance was assessed with the Cognitive Abilities Screening Instrument, and subjects were stratified into four groups: low, low normal, mid normal, and high normal. For the dementia analyses, subjects were divided into five mutually exclusive groups: AD (n = 47), vascular dementia (n = 35), mixed/other types of dementia (n = 50), low cognitive test scorers without diagnosed dementia (n = 254), and cognitively intact (n = 2,999; reference). Results: In a multivariate model controlling for other factors, a significant protective effect was found for vascular dementia in men who had reported taking both vitamin E and C supplements in 1988 (odds ratio [OR], 0.12; 95% CI, 0.02 to 0.88). They were also protected against mixed/other dementia (OR, 0.31; 95% CI, 0.11 to 0.89). No protective effect was found for Alzheimer’s dementia (OR, 1.81; 95% CI, 0.91 to 3.62). Among those without dementia, use of either vitamin E or C supplements alone in 1988 was associated significantly with better cognitive test performance at the 1991 to 1993 examination (OR, 1.25; 95% CI, 1.04 to 1.50), and use of both vitamin E and C together had borderline significance (OR, 1.18; 95% CI, 0.995 to 1.39). Conclusions: These results suggest that vitamin E and C supplements may protect against vascular dementia and may improve cognitive function in late life.

Generation of mice from wild-type and targeted ES cells by nuclear cloning

Abstract: Acknowledgements We thank T. Perry for critical and useful comments on the manuscript. R.Y. acknowledges financial support from ProBio America. Teruhiko Wakayama1,3, Hiroyuki Tateno1, Peter Mombaerts2 & Ryuzo Yanagimachi1 1University of Hawaii Medical School, Department of Anatomy and Reproductive Biology, Honolulu, Hawaii, USA. 2The Rockefeller University, New York, New York, USA. 3Present address: The Rockefeller University, New York, NY, USA. Correspondence should be addressed to T.W. (e-mail: wakayat@rockvax.rockefeller.edu).

Chronic social stress reduces dendritic arbors in CA3 of hippocampus and decreases binding to serotonin transporter sites.

Abstract: Male rats housed in mixed-sex groups in a visible burrow system (VBS) form a dominance hierarchy in which subordinate animals show stress-related changes in behavior, endocrine function and neurochemistry. Dominants also appear to be moderately stressed compared to controls, although these animals do not develop the more pronounced behavioral and physiological deficits seen in the subordinates. In the present study, we examined the effects of chronic psychosocial stress on the morphology of Golgi-impregnated CA3 pyramidal neurons. In addition, since serotonin has been implicated in the mechanisms mediating the dendritic remodeling seen with other chronic stress regimens, we used quantitative autoradiography to measure binding to the serotonin transporter (5HTT) in hippocampus and dorsal and median raphe. Chronic social stress led to a decrease in the number of branch points and total dendritic length in the apical dendritic trees of CA3 pyramidal neurons in dominant animals compared to unstressed controls; subordinates also had a decreased number of dendritic branch points. [(3)H]paroxetine binding to the 5HTT was decreased in Ammon's horn in both dominants and subordinates compared to controls, while 5HTT binding remained unchanged in dentate gyrus and raphe. The similarity of the changes in 5HTT binding and dendritic arborization between both groups of VBS animals, despite apparent differences in stressor severity, suggests that these changes may be part of the normal adaptive response to chronic social stress. The mechanisms underlying dendritic remodeling in CA3 pyramidal neurons are likely to involve stress-induced changes in glucocorticoids and in 5HT and other transmitters.

X-Chromosome Inactivation in Cloned Mouse Embryos

Abstract: To study whether cloning resets the epigenetic differences between the two X chromosomes of a somatic female nucleus, we monitored X inactivation in cloned mouse embryos Both X chromosomes were active during cleavage of cloned embryos, followed by random X inactivation in the embryo proper In the trophectoderm (TE), X inactivation was nonrandom with the inactivated X of the somatic donor being chosen for inactivation When female embryonic stem cells with two active X chromosomes were used as donors, random X inactivation was seen in the TE and embryo These results demonstrate that epigenetic marks can be removed and reestablished on either X chromosome during cloning Our results also suggest that the epigenetic marks imposed on the X chromosomes during gametogenesis, responsible for normal imprinted X inactivation in the TE, are functionally equivalent to the marks imposed on the chromosomes during somatic X inactivation

Relationships between perception of engagement with health care provider and demographic characteristics, health status, and adherence to therapeutic regimen in persons with HIV/AIDS.

Abstract: The purpose of this descriptive, correlational study was to examine the relationships between perception of engagement with health care provider and demographic characteristics, health status, and adherence to therapeutic regimen in persons with HIV/AIDS. The convenience sample of 707 non-hospitalized persons receiving health care for HIV/AIDS was recruited from seven U.S. sites. All measures were self-report. Perception of engagement with health care provider was measured by the newly developed Engagement with Health Care Provider scale. Adherence to therapeutic regimen included adherence to medications, provider advice, and appointments. Health status was measured by the Medical Outcomes Study Short Form 36 (MOS SF-36), Living with HIV scale, CD4 count, and length of time known to be HIV-positive. There were no significant relationships between engagement with health care provider and age, gender, ethnicity, and type of health care provider. Subscales of the MOS SF-36 and Living with HIV explained a sig...

Cross-cultural Training: A Review

Abstract: Dans cet article, nous suivons l’e´volution des concepts qui font partie de la litte´rature de ces 50 dernie`res anne´es sur la formation trans-culturelle en passant en revue quelques e´tudes qui ont fait date. Apre`s avoir de´battu des recherches et pratiques au fil des de´cennies, nous poursuivons en identifiant les grands courrants de recherche dans ce domaine et nous livrons a` quelques conjonctures suppositions sur les directions qui peuvent etre prises dans l’avenir.

Attainment of the Theoretical Yield of Carbon from Biomass

Abstract: Previous work has shown that very high yields of charcoal are obtained when pyrolysis of the biomass feedstock is conducted at elevated pressure in a closed vessel, wherein the pyrolytic vapors are held captive and in contact with the solid products of pyrolysis In this paper, we show that, for some biomass species, the yield of carbon produced by this process effectively attains the theoretical value predicted to exist when thermochemical equilibrium is realized Various agricultural wastes (eg, kukui nut, macadamia nut, and pecan shells) and tropical species (eg, eucalyptus, leucaena, and bamboo) offer higher yields of carbon than the hardwoods traditionally employed by industry in the US and Europe Moreover, the yields of carbon from oat and rice hulls and from sunflower seed hulls are nearly as high as the yields of carbon from hardwoods There is a correlation between the yield of carbon and the acid-insoluble lignin content of the feed Charcoal briquettes made from agricultural wastes and lump charcoal from tropical species are promising sources of renewable carbon for use in the smelting of metal ores

The missing link: Early methane ("T") dwarfs in the sloan digital Sky Survey

Abstract: We report the discovery of three cool brown dwarfs that fall in the effective temperature gap between the latest L dwarfs currently known, with no methane absorption bands in the 1-2.5 µm range, and the previously known methane (T) dwarfs, whose spectra are dominated by methane and water. The newly discovered objects were detected as very red objects in the Sloan Digital Sky Survey imaging data and have JHK colors between the red L dwarfs and the blue Gl 229B-like T dwarfs. They show both CO and CH(4) absorption in their near-infrared spectra in addition to H(2)O, with weaker CH(4) absorption features in the H and K bands than those in all other methane dwarfs reported to date. Due to the presence of CH(4) in these bands, we propose that these objects are early T dwarfs. The three form part of the brown dwarf spectral sequence and fill in the large gap in the overall spectral sequence from the hottest main-sequence stars to the coolest methane dwarfs currently known.

The future of coral reefs

Abstract: Coral reefs have been degrading faster than they have been recovering (Done 1992; Ginsburg 1994; Hughes 1994; Grigg and Birkeland 1997; McManus and Vergara 1998; Wilkinson 1993, 1998) and they have been accruing in their degraded states because they achieve alternate stable states of algae instead of corals (Knowlton et al 1981; Knowlton 1992; Done 1992; Hughes 1994), and because rates of damage are much greater than rates of recovery (Muzik 1985; Birkeland 1997a) With the accumulation of reefs in alternative stable states, the total area of some reefs previously dominated by coral is decreasing over time (Muzik 1985; Knowlton et al 1981, 1990; Wilkinson 1993), and the balance has been continuously in the negative for corals over the past few decades (LaPointe 1989; Hallock et al 1993; Birkeland 1997a) Furthermore, human activities are now bringing about environmental changes on a global scale (Smith and Buddemeier 1992; Hoegh-Guldberg 1999; Tsuchiya 1999; Wilkinson et al 1999) which alter the basic conditions and nature of environmental processes in the domain

Interannual Variability of the Kuroshio Extension System and Its Impact on the Wintertime SST Field

Abstract: Altimetry data from the first 7-yr TOPEX/Poseidon (T/P) mission (October 1992‐September 1999) are analyzed to investigate the interannual variability in regions of the Kuroshio Extension and its southern recirculation gyre. Large-scale, interannual changes of the Kuroshio Extension system are characterized by the oscillation between an elongated state and a contracted state. In the elongated state, the Kuroshio Extension has a larger eastward surface transport, a greater zonal penetration, and a more northerly zonal-mean path. All these characteristics are closely connected to the presence of an intense, zonally elongated southern recirculation gyre. In its contracted state, the Kuroshio Extension has a smaller eastward surface transport, a more southerly mean path, and is accompanied by a weaker southern recirculation gyre. During the T/P period, the Kuroshio Extension changed from the elongated state in 1992‐93 to the contracted state in 1996‐97, and back to the elongated state since late 1997. In addition to these large-scale changes, the mesoscale eddy field also exhibited prominent interannual changes in the Kuroshio Extension region. In the upstream region between the Izu Ridge and the Shatsky Rise, the eddy kinetic energy level was generally low while the Kuroshio Extension was in its elongated state, and high while in the contracted state. Downstream of the Shatsky Rise, on the other hand, the EKE level was high (low) when the Kuroshio Extension was in the elongated (contracted) state. The large-scale, interannual changes in the Kuroshio Extension system have a significant impact on the regional wintertime SST anomaly field: the warm (cold) wintertime SST anomalies tend to persist in years when the Kuroshio Extension is in its elongated (contracted) state. A diagnostic analysis of the surface ocean heat balance indicates that the nonseasonal geostrophic advection by the ocean circulation works to reduce (increase) the wintertime SST anomalies when the Kuroshio Extension changes from an elongated (contracted) state to a contracted (elongated) state. The SST anomalies associated with the large-scale changes of the Kuroshio Extension have an area-averaged, peak-topeak amplitude of .18C and appear independent of the interannual SST changes in the tropical Pacific Ocean.

Interannual Variability of Summer Monsoon Onset over the Western North Pacific and the Underlying Processes

Abstract: Climatological summer monsoon onset over the South China Sea (SCS) and the western North Pacific (WNP) (defined as the region of 108‐208N, 1208‐1608E) displays three distinct stages. Around mid-May, monsoon rain commences in the SCS and the Philippines. In early to mid-June, the monsoon rain extends to the southwestern Philippine Sea. After mid-July, the rainy season starts in the northeastern part of the WNP. The onset anomaly, however, displays an in-phase interannual variation across the entire WNP domain. The standard deviation of the onset date increases eastward from 3 pentads in the SCS to 5 pentads in the northeastern part of the domain. The large onset variability in the WNP is mainly attributed to large year-to-year changes of the seasonal cycle. .

Brain Aging and Midlife Tofu Consumption

Abstract: Objective: To examine associations of midlife tofu consumption with brain function and structural changes in late life.Methods: The design utilized surviving participants of a longitudinal study established in 1965 for research on heart disease, stroke, and cancer. Information on consumption of selected foods was available from standardized interviews conducted 1965–1967 and 1971–1974. A 4-level composite intake index defined “low-low” consumption as fewer than two servings of tofu per week in 1965 and no tofu in the prior week in 1971. Men who reported two or more servings per week at both interviews were defined as “high-high” consumers. Intermediate or less consistent “low” and “high” consumption levels were also defined. Cognitive functioning was tested at the 1991–1993 examination, when participants were aged 71 to 93 years (n=3734). Brain atrophy was assessed using neuroimage (n=574) and autopsy (n=290) information. Cognitive function data were also analyzed for wives of a sample of study participan...

The burden of infection in long-term care

Abstract: Available data, although fragmentary, indicate that infections impose a large burden on long-term-care facilities (LTCFs) in the United States. Endemic infections occur with frequencies estimated to range between 1.64 and 3.83 million per year. These estimates rival or exceed the annual tally for nosocomial infections in acute-care settings. Infections associated with outbreaks caused by respiratory, gastrointestinal, and antimicrobial-resistant pathogens burden LTCFs even further. As judged by antimicrobial use, transfers to hospital, and mortality figures, infections in LTCFs are not trivial. Moreover, annual costs associated with these infections appear to exceed $1 billion. Recognition of the burden associated with infection in LTCFs helps to identify research priorities for this rapidly growing area of healthcare.

Caregiver burden and burnout. A guide for primary care physicians.

Abstract: Caregiver burden and burnout are important, prevalent, and preventable. Physicians aware of the symptoms and signs can better assess, identify, prevent, and intervene in these situations. Such efforts result in improved quality of life for both patients and their loved ones.

Predicting Invasive Plants: Prospects for a General Screening System Based on Current Regional Models

Abstract: Screening systems for predicting invasive plants have been independently developed for the non-indigenous floras of North America, the South African fynbos, and Australia. To evaluate the performance of these screening systems outside the regions for which they were developed, we tested them for the non-indigenous flora of the Hawaiian Islands. When known invasive plant species in the Hawaiian Islands were evaluated using the North American and Australian systems, 82% and 93% of the species were predicted to be invasive, respectively, and the remainder were classified as requiring further study. The South African fynbos system correctly predicted only 60% of the invasive species in the Hawaiian Islands. All three screening systems correctly classified a majority of the non-invaders as non-invasive. The Australian system has several advantages over the other systems, including the highest level of correct identification of invaders (>90%), ability to evaluate non-woody plants, and ability to evaluate a species even when the answers to some questions are unknown. Nevertheless, with the Australian system, a large fraction of species known not to be invasive were recommended for further study before importing, so there remains room for improvement in identifying non-invasive species. Based on our results for the Hawaiian Islands and a previous evaluation in New Zealand, the Australian system appears to be a promising template for building a globally applicable system for screening out invasive plant introductions.

Iterative decoding of one-step majority logic deductible codes based on belief propagation

Abstract: Previously, the belief propagation (BP) algorithm has received a lot of attention in the coding community, mostly due to its near-optimum decoding for low-density parity check (LDPC) codes and its connection to turbo decoding. In this paper, we investigate the performance achieved by the BP algorithm for decoding one-step majority logic decodable (OSMLD) codes. The BP algorithm is expressed in terms of likelihood ratios rather than probabilities, as conventionally presented. The proposed algorithm fits better the decoding of OSMLD codes with respect to its numerical stability due to the fact that the weights of their check sums are often much higher than that of the corresponding LDPC codes. Although it has been believed that OSMLD codes are far inferior to LDPC codes, we show that for medium code lengths (say between 200-1000 bits), the BP decoding of OSMLD codes can significantly outperform BP decoding of their equivalent LDPC codes. The reasons for this behavior are elaborated.

Serum lipid effects of a high-monounsaturated fat diet based on macadamia nuts.

Abstract: Methods: A randomized crossover trial of three 30-day diets was conducted in 30 volunteers aged 18 to 53 years from a free-living population. Each was fed a “typical American” diet high in saturated fat (37% energy from fat); an American Heart Association Step 1 diet (30% energy from fat); and a macadamia nut‐ based monounsaturated fat diet (37% energy from fat) in random order. Serum total cholesterol, high-density lipoprotein cholesterol, and triglyceride levels were measured.