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Institution

University of Hawaii at Manoa

EducationHonolulu, Hawaii, United States
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.


Papers
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Journal ArticleDOI
TL;DR: In this paper, a carbon cycle model was used to constrain the initial carbon pulse to a magnitude of 3,000 C or less, with an isotopic composition lighter than −50‰.
Abstract: About 55 million years ago global surface temperatures increased by 5–9 ∘C within a few thousand years, following a pulse of carbon released to the atmosphere. Analysis of existing data with a carbon cycle model indicates that this carbon pulse was too small to cause the full amount of warming at accepted values for climate sensitivity. The Palaeocene–Eocene Thermal Maximum (about 55 Myr ago) represents a possible analogue for the future and thus may provide insight into climate system sensitivity and feedbacks1,2. The key feature of this event is the release of a large mass of 13C-depleted carbon into the carbon reservoirs at the Earth’s surface, although the source remains an open issue3,4. Concurrently, global surface temperatures rose by 5–9 ∘C within a few thousand years5,6,7,8,9. Here we use published palaeorecords of deep-sea carbonate dissolution10,11,12,13,14 and stable carbon isotope composition10,15,16,17 along with a carbon cycle model to constrain the initial carbon pulse to a magnitude of 3,000 Pg C or less, with an isotopic composition lighter than −50‰. As a result, atmospheric carbon dioxide concentrations increased during the main event by less than about 70% compared with pre-event levels. At accepted values for the climate sensitivity to a doubling of the atmospheric CO2 concentration1, this rise in CO2 can explain only between 1 and 3.5 ∘C of the warming inferred from proxy records. We conclude that in addition to direct CO2 forcing, other processes and/or feedbacks that are hitherto unknown must have caused a substantial portion of the warming during the Palaeocene–Eocene Thermal Maximum. Once these processes have been identified, their potential effect on future climate change needs to be taken into account.

379 citations

Journal ArticleDOI
TL;DR: Direct methods for recovering the motion of an observer in a static environment in the case of pure rotation, pure translation, and arbitrary motion when the rotation is known are developed.
Abstract: We have developed direct methods for recovering the motion of an observer in a static environment in the case of pure rotation, pure translation, and arbitrary motion when the rotation is known. Some of these methods are based on the minimization of the difference between the observed time derivative of brightness and that predicted from the spatial brightness gradient, given the estimated motion. We minimize the square of the integral of this difference taken over the image region of interest. Other methods presented here exploit the fact that surfaces have to be in front of the observer in order to be seen. We do not establish point correspondences, nor do we estimate the optical flow. We use only first-order derivatives of the image brightness, and we do not assume an analytic form for the surface. We show that the field of view should be large to accurately recover the components of motion in the direction toward the image region. We also demonstrate the importance of points where the time derivative of brightness is small and discuss difficulties resulting from very large depth ranges. We emphasize the need for adequate filtering of the image data before sampling to avoid aliasing, in both the spatial and temporal dimensions.

379 citations

Journal ArticleDOI
TL;DR: Results suggest that vitamin E and C supplements may protect against vascular dementia and may improve cognitive function in late life.
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.

378 citations

Journal ArticleDOI
TL;DR: In this article, the authors demonstrate that other physicochemical parameters are much stronger predictors of SOM content, with clay content having relatively little explanatory power, whereas with increasing moisture availability and acidity, iron-and aluminum-oxyhydroxides emerged as better predictors.
Abstract: Improved quantification of the factors controlling soil organic matter (SOM) stabilization at continental to global scales is needed to inform projections of the largest actively cycling terrestrial carbon pool on Earth, and its response to environmental change Biogeochemical models rely almost exclusively on clay content to modify rates of SOM turnover and fluxes of climate-active CO2 to the atmosphere Emerging conceptual understanding, however, suggests other soil physicochemical properties may predict SOM stabilization better than clay content We addressed this discrepancy by synthesizing data from over 5,500 soil profiles spanning continental scale environmental gradients Here, we demonstrate that other physicochemical parameters are much stronger predictors of SOM content, with clay content having relatively little explanatory power We show that exchangeable calcium strongly predicted SOM content in water-limited, alkaline soils, whereas with increasing moisture availability and acidity, iron- and aluminum-oxyhydroxides emerged as better predictors, demonstrating that the relative importance of SOM stabilization mechanisms scales with climate and acidity These results highlight the urgent need to modify biogeochemical models to better reflect the role of soil physicochemical properties in SOM cycling

378 citations

Journal ArticleDOI
TL;DR: In this paper, the authors argue that commonly used ranking and rating methods of value surveys may have low validity in cross-cultura l value comparisons because participants' reports about values can be affected by factors such as cultural differences in the meaning of particular value terms as well as the possibility that some value judgments are based on social comparison or deprivation rather than on any direct reading of personal preferences.
Abstract: The authors argue that commonly used ranking and rating methods of value surveys may have low validity in cross-cultura l value comparisons because participants' reports about values can be affected by factors such as cultural differences in the meaning of particular value terms as well as the possibility that some value judgments are based on social comparison or deprivation rather than on any "direct reading" of personal preferences. Four different value survey methods—ranking, rating, attitude scale, and behavioral scenario methods—were compared. It was found that ranking and rating methods of assessing differences between Chinese and Americans had low convergence with each other and with the criterion of cultural experts' independent judgments. Attitude questions had slight and nonsignificant convergence with the expert judgment criterion. A scenario method of value assessment, however, yielded reasonable criterion validity.

378 citations


Authors

Showing all 13867 results

NameH-indexPapersCitations
Pulickel M. Ajayan1761223136241
Steven N. Blair165879132929
Qiang Zhang1611137100950
Jack M. Guralnik14845383701
Thomas J. Smith1401775113919
James A. Richardson13636375778
Donna Neuberg13581072653
Jian Zhou128300791402
Eric F. Bell12863172542
Jorge Luis Rodriguez12883473567
Bin Wang126222674364
Nicholas J. Schork12558762131
Matthew Jones125116196909
Anthony F. Jorm12479867120
Adam G. Riess118363117310
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202362
2022244
20211,111
20201,164
20191,151
20181,154