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We use multivariate output from a hydrodynamic model of the Gulf of Alaska (GOA) to explore the covariance among its physical state and air/sea fluxes. We attempt to summarize this coupled variability using a limited set of patter...
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We use multivariate output from a hydrodynamic model of the Gulf of Alaska (GOA) to explore the covariance among its physical state and air/sea fluxes. We attempt to summarize this coupled variability using a limited set of patterns, and examine their correlation to three large-scale climate indices relevant to the Northeast Pacific. This analysis is focused on perturbations from monthly climatology of the following attributes of the GOA: sea surface temperature, sea surface height, mixed layer depth, sea surface salinity, latent heat flux, sensible heat flux, shortwave irradiance, net long wave irradiance, currents at 40 m depth, and wind stress. We identified two multivariate modes, both substantially correlated with the Pacific Decadal Oscillation (PDO) and Multivariate El Nino (MEI) indices on interannual timescales, which together account for similar to 30% of the total normalized variance of the perturbation time series. These two modes indicate the following covarying events during periods of positive PDO/MEI: (1) anomalously warm, wet and windy conditions (typically in winter), with elevated coastal SSH, followed 2-5 months later by (2) reduced cloud cover, with emerging shelf-break eddies. Similar modes are found when the analysis is performed separately on the eastern and western GOA; in general, modal amplitudes appear stronger in the western GOA. (C) 2016 Elsevier Ltd All rights reserved.
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In some populations the phenomenon of partial migration develops where some individuals stay in a given habitat rather than move with the migratory component. Depending on the selective pressures, the individuals that stay may be ...
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In some populations the phenomenon of partial migration develops where some individuals stay in a given habitat rather than move with the migratory component. Depending on the selective pressures, the individuals that stay may be larger, smaller or similar in size to those that move. Freshwater movements of juvenile sockeye salmon (Oncorhynchus nerka Walbaum) fry vary among and within populations, and can be complex, especially in interconnected lake systems. We examined variation of movement patterns by a sockeye salmon population in an interconnected lake system during a period of rapid natural habitat change and found that fry migrating downstream were shorter, had lower body condition, and were more likely ill and moribund compared with fish remaining in the lake. However, otolith microstructure measurements indicated that emigrants did not grow significantly slower than residents prior to downstream movement. We show that patterns (i.e., demography of migrants, timing of movement) of downstream movement have changed since the 1970s, corresponding to changes in rearing habitat. Our findings parallel the results with other salmonid species and are generally consistent with the paradigm that density-dependent interactions from declining habitat availability or quality result in the downstream movement of competitively inferior individuals, although the mechanisms governing downstream migration are unclear in this system.
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Standard statistics and discriminant and cluster analyses were used to study the variability of craniometric characteristics in Beringian Ursus arctos L. and to specify its taxonomic status. The eastern Siberian subspecies U. a. j...
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Standard statistics and discriminant and cluster analyses were used to study the variability of craniometric characteristics in Beringian Ursus arctos L. and to specify its taxonomic status. The eastern Siberian subspecies U. a. jeniseensis, belonging to the "arctos" group. dwells the extreme northeastern territory of Siberia, whereas bears of the Far Eastern "piscator" group are represented by two subspecies - Kamchatkan U. a. piscator and Ussurian U. a beringianus. Large and broad skulls of Kamchatkan bears are similar to those in the bear population (U. a. middendorffi), inhabiting Kod'yak and Afognak Islands. U. a. beringianus has common features with U. a. dalii from Alaska Peninsula and its Pacific coast. U. a. jeniseensis is relative to U. a. horribilis from Central and Northern Alaska. History and migratory routes of various U. arctos forms in Beringian region are discussed.
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The survival and adult size of pink salmon Oncorhynchus gorbuscha marked as recently emigrating fry with coded ire tags (CWTs) were compared with those of Sibling groups that were either unmarked or marked by removing a ventral (p...
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The survival and adult size of pink salmon Oncorhynchus gorbuscha marked as recently emigrating fry with coded ire tags (CWTs) were compared with those of Sibling groups that were either unmarked or marked by removing a ventral (pelvic) fin. Prerelease mortality was significantly higher for coded-wire-tagged fish. Survival from fry release to adult return was equal to or less than that of fish with central fin clips. Pink salmon marked with CWTs were similar in size at return to pink salmon Both ventral fin clips but significantly smaller than unmarked fish. These results indicate that reduced growth after marking contributes to the loader survival reported in other Studies of pink salmon marked with CWTs or fin clips. Marking pink salmon as recently emigrating fry with CWTs provides a powerful tool for differentiating between a large number of treatment groups and categories, but doing so will affect survival and size at return and is more detrimental to survival than central tin removal.
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Objective Compared to non-Natives in Alaska, the Alaska Native population has a postneonatal mortality rate 2.3 times higher (95% CI 1.9, 2.7). The objective of the study was to identify variables that account for this elevated ri...
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Objective Compared to non-Natives in Alaska, the Alaska Native population has a postneonatal mortality rate 2.3 times higher (95% CI 1.9, 2.7). The objective of the study was to identify variables that account for this elevated risk. Methods The dataset used included birth and death certificate records for all Alaska-resident live births and infant deaths occurring during 1992–2004. Race was defined as Alaska Native or non-Native. The association between race and postneonatal mortality was examined using univariate, stratified and regression analyses. Variables were considered confounding if they resulted in a change of at least 10% in the odds ratio between race and postneonatal mortality when added to a bivariate model, or when removed from a multivariate model. Results In stratified analysis, race remained associated with postneonatal mortality within most categories of marital status, maternal education, maternal age, prenatal tobacco or alcohol use, prenatal care utilization, parity and residence. The odds ratio between race and postneonatal mortality was reduced to 1.3 (95% CI 1.0, 1.6) by controlling for education, a composite variable of marital status and the presence of father’s name on the birth certificate, and prenatal tobacco or alcohol use. Conclusions A small number of potentially modifiable factors explain most of the postneonatal mortality disparity between Alaska Natives and non-Natives, leaving a relatively small increase in risk. These findings suggest that by targeting Alaska Native women who display these characteristics, the postneonatal mortality gap may be reduced.
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The present study compared the sensory and physicochemical characterizations of Alaska pollock Theragra chalcogramma roe according to the L, M, S, 2S, KA, KB, KC, and G grades. The mean weights of the Alaska pollock roe were 81.2 ...
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The present study compared the sensory and physicochemical characterizations of Alaska pollock Theragra chalcogramma roe according to the L, M, S, 2S, KA, KB, KC, and G grades. The mean weights of the Alaska pollock roe were 81.2 g (74.1-85.7 g) in the L grade, 48.4 g (41.1 -54.8 g) in the M grade, 38.6 g (33.5-45.6 g) in the S grade, 29.3 g (25.7-34.2 g) in the 2S grade, 45.7 g (41.4-50.0 g) in the KA grade, 41.4 g (37.7-46.1 g) in the KB grade, 38.3 g (36.0-42.6 g) in the KC grade, and 15.0 g (14.2-15.6 g) in the G grade. The results of the sensory (transparency, physical damage, texture, and odor) and physicochemical (moisture, amino nitrogen and volatile basic nitrogen contents, Hunter redness, and texture) evaluations revealed that, in the normal group, the quality of Alaska pollock roe was highest in the L grade followed by the M, S, and 2S grades whereas, in the cut-group order, the quality was highest in the KA grade followed by the KB, KC, and G grades. The present results suggest that theL, M, S, 2S, KA, and KB grades could be used for high-quality Alaska pollock roe products.
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The Canada Lynx (Lynx canadensis) is poorly documented in southwest Alaska, where dominant habitats are generally not conducive to supporting persistent Snowshoe Hare (Lepus americanus) or Lynx populations. We compiled recent and ...
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The Canada Lynx (Lynx canadensis) is poorly documented in southwest Alaska, where dominant habitats are generally not conducive to supporting persistent Snowshoe Hare (Lepus americanus) or Lynx populations. We compiled recent and historic records from southwest Alaska that collectively suggest that persistent Lynx populations occur at the base of the Alaska Peninsula where boreal forest transitions to open tundra habitats. Records show that Lynx, at least periodically, also occur throughout the entirety of the Alaska Peninsula and that a self-sustaining and relatively isolated population occurs in an isolated stand of Poplar forest near Mother Goose Lake, which probably represents one of the westernmost Lynx populations in North America. These records extend the known distribution of the species by approximately 380 km southwest along the Alaska Peninsula. These records also suggest that Lynx occur in areas where Snowshoe Hare are rare or absent, and that other prey species may facilitate the persistence of distinct population segments at the extent of their range in Alaska.
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Displacement, velocity, and velocity-squared records of P and SH body waves recorded at teleseismic distances are analyzed to determine the rupture characteristics of the Denali fault, Alaska, earthquake of 3 November 2002 (M-W 7....
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Displacement, velocity, and velocity-squared records of P and SH body waves recorded at teleseismic distances are analyzed to determine the rupture characteristics of the Denali fault, Alaska, earthquake of 3 November 2002 (M-W 7.9, Me 8.1). Three episodes of rupture can be identified from broadband (similar to0.1-5.0 Hz) waveforms. The Denali fault earthquake started as a M-W 7.3 thrust event. Subsequent right-lateral strike-slip rupture events with centroid depths of 9 km occurred about 22 and 49 see later. The teleseismic P waves are dominated by energy at intermediate frequencies (0.1-1 Hz) radiated by the thrust event, while the SH waves are dominated by energy at lower frequencies (0.05-0.2 Hz) radiated by the strike-slip events. The strike-slip events exhibit strong directivity in the teleseismic SH waves. Correcting the recorded P-wave acceleration spectra for the effect of the free surface yields an estimate of 2.8 x 10(15) N m for the energy radiated by the thrust event. Correcting the recorded SH-wave acceleration spectra similarly yields an estimate of 3.3 x 10(16) N m for the energy radiated by the two strike-slip events. The average rupture velocity for the strike-slip rupture process is 1.1beta-1.2beta. The strike-slip events were located 90 and 188 km east of the epicenter. The rupture length over which significant or resolvable energy is radiated is, thus, far shorter than the 340-km fault length over which surface displacements were observed. However, the seismic moment released by these three events, 4 x 10(20) N m, was approximately half the seismic moment determined from very low-frequency analyses of the earthquake. The difference in seismic moment can be reasonably attributed to slip on fault segments that did not radiate significant or coherent seismic energy. These results suggest that very large and great strike-slip earthquakes can generate stress pulses that rapidly produce substantial slip with negligible stress drop and little discernible radiated energy on fault segments distant from the initial point of nucleation. The existence of this energy-deficient rupture mode has important implications for the evaluation of the seismic hazard of very large strike-slip earthquakes.
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ObjectiveThis study examined self-reported age of tobacco initiation (cigarette smoking and smokeless tobacco [ST] use) and explored potential sex and generational group influences on tobacco use onset among Alaska Native (AN) adu...
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ObjectiveThis study examined self-reported age of tobacco initiation (cigarette smoking and smokeless tobacco [ST] use) and explored potential sex and generational group influences on tobacco use onset among Alaska Native (AN) adult ever tobacco users.MethodsSecondary analysis of consolidated data from the Western Alaska Tribal Collaborative for Health (WATCH) study comprised 2800 AN adult ever tobacco users (1490 women, 1310 men; mean age?=?39.2?years) from two rural western Alaska regions. ST use data were limited to one region. Logistic regression was used to examine potential sex and generational group (age 18–29, 30–49, ≥50) effects on initiation at ≤13?years of age.ResultsThirty-seven percent of the sample reported using any tobacco product by age 13?years. Initiation of any ST use by age 13 was greater than for cigarette smoking (52.7% vs. 18.2%), and women were more likely than men to report initiation of any ST use at ≤13?years (52.6% vs. 38.4%). Nearly one-third of ever smokers (31%) initiated in young adulthood (ages 18–29). For ST use, logistic regression analyses revealed significant sex differences (women more likely to initiate by 13?years of age than men) and generational group effects with younger and middle age groups more likely to report initiation ≤13?years compared to the eldest participants. For smoking, no sex differences were observed but the youngest generational group was more likely to report initiation by age 13 compared to the eldest group.ConclusionsEarlier age of tobacco initiation is found among younger generations of AN people. Findings highlight the need to focus prevention efforts on initiation of smoking in young adulthood and uptake of ST use among girls.
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