3,240 research outputs found

    Stage-specific vertical distribution of Alaska plaice (Pleuronectes quadrituberculatus) eggs in the eastern Bering Sea

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    The stage-specific distribution of Alaska plaice (Pleuronectes quadrituberculatus) eggs in the southeastern Bering Sea was examined with collections made in mid-May in 2002, 2003, 2005, and 2006. Eggs in the early stages of development were found primarily offshore of the 40-m isobath. Eggs in the middle and late stages of development were found inshore and offshore of the 40-m isobath. There was some evidence that early-stage eggs occur deeper in the water column than late-stage eggs, although year-to-year variability in that trend was observed. Most eggs were in the later stages of development; therefore the majority of spawning is estimated to have occurred a few weeks before collection—probably April—and may be highly synchronized among local spawning areas. Results indicate that sampling with continuous underway fish egg collectors(CUFES) should be supplemented with sampling of the entire water column to ensure adequate samples of all egg stages of Alaska plaice. Data presented offer new information on the stage-dependent horizontal and vertical distribution of Alaska plaice eggs in the Bering Sea and provide further evidence that the early life history stages of this species are vulnerable to near-surface variations in hydrographical conditions and climate forcing

    A Three-Dimensional Analysis of Cham Sentences

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    Middle atmosphere measurements of small-scale electron density irregularities and ion properties during the MAC/Epsilon campaign

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    Rocket payloads designed to measure small scale electron density irregularities and ion properties in the middle atmosphere were flown with each of the three main salvos of the MAC/Epsilon campaign conducted at the Andoya Rocket Range, Norway, during October to November 1987. Fixed bias, hemispheric nose tip probes measured small scale electron density irregularities, indicative of neutral air turbulence, during the rocket's ascent; and subsequently, parachute-borne Gerdien condensers measured the region's polar electrical conductivity, ion mobility and density. One rocket was launched during daylight (October 15, 1052:20 UT), and the other two launches occurred at night (October 21, 2134 UT: November 12, 0021:40 UT) under moderately disturbed conditions which enhanced the detection and measurement of turbulence structures. A preliminary analysis of the real time data displays indicates the presence of small scale electron density irregularities in the altitude range of 60 to 90 km. Ongoing data reduction will determine turbulence parameters and also the region's electrical properties below 90 km

    Atlas of abundance and distribution patterns of ichthyoplankton from the Northeast Pacific Ocean and Bering Sea ecosystems: based on research conducted by the Alaska Fisheries Science Center (1972–1996)

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    This regional atlas summarizes and illustrates the distribution and abundance patterns of fish eggs and larvae of 102 taxa within 34 families found in the Northeast Pacific Ocean including the Bering Sea, Gulf of Alaska, and U.S. west coast ecosystems. Data were collected over a 20+ year period (1972–1996) by the Recruitment Processes Program of the Alaska Fisheries Science Center (AFSC). Ichthyoplankton catch records used in this atlas were generated from 11,379 tows taken during 100 cruises. For each taxon, general life history data are briefly summarized from the literature. Published information on distribution patterns of eggs and larvae are reviewed for the study area. Data from AFSC ichthyoplankton collections were combined to produce an average spatial distribution for each taxon. These data were also used to estimate mean abundance and percent occurrence by year and month, and relative abundance by larval length and season. Abundance from each tow was measured as catch per 10 m2 surface area. A larval distribution and abundance map was produced with a geographic information system using ArcInfo software. For taxa with identifiable pelagic eggs, distribution maps showing presence or absence of eggs are presented. Presence or absence of adults in the study area is mapped based on recent literature and data from AFSC groundfish surveys. Distributional records for adults and early life history stages revealed several new range extensions. (PDF file contains 288 pages.

    History of the Ile d\u27Orleans

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    This English translation of L.P. Turcotte\u27s Histoire de l\u27Ile d\u27Orleans, originally published in French in 1867, will give today\u27s English-speaking descendants of the early French colonists a peek into the lives of the 17th-century settlers of New France. This book focuses on the history of the Ile d\u27Orleans – a small island in the middle of the river just north of Québec City – where many early settlers established their homesteads. Originally published in Québec: Atelier Typographique du Canadien, 21 rue de la Montagne, Basse-Ville, Québec City, 1867 Translated into English by Dr. Elizabeth Blood, Salem State University, Salem, Massachusetts, 2019https://digitalcommons.salemstate.edu/fchc/1000/thumbnail.jp

    Comparison of near-interface traps in Al2_2O3_3/4H-SiC and Al2_2O3_3/SiO2_2/4H-SiC structures

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    Aluminum oxide (Al2O3) has been grown by atomic layer deposition on n-type 4H-SiC with and without a thin silicon dioxide (SiO2) intermediate layer. By means of Capacitance Voltage and Thermal Dielectric Relaxation Current measurements, the interface properties have been investigated. Whereas for the samples with an interfacial SiO2 layer the highest near-interface trap density is found at 0.3 eV below the conduction band edge, Ec, the samples with only the Al2O3 dielectric exhibit a nearly trap free region close to Ec. For the Al2O3/SiC interface, the highest trap density appears between 0.4 to 0.6 eV below Ec. The results indicate the possibility for SiC-based MOSFETs with Al2O3 as the gate dielectric layer in future high performance devices.Comment: 3 figures. Applied Physics Letters, accepted for publicatio

    Theory of quantum dot spin-lasers

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    We formulate a model of a semiconductor Quantum Dot laser with injection of spin-polarized electrons. As compared to higher-dimensionality structures, the Quantum-Dot-based active region is known to improve laser properties, including the spin-related ones. The wetting layer, from which carriers are captured into the active region, acts as an intermediate level that strongly influences the lasing operation. The finite capture rate leads to an increase of lasing thresholds, and to saturation of emitted light at higher injection. In spite of these issues, the advantageous threshold reduction, resulting from spin injection, can be preserved. The "spin-filtering" effect, i.e., circularly polarized emission at even modest spin-polarization of injection, remains present as well. Our rate-equations description allows to obtain analytical results and provides transparent guidance for improvement of spin-lasers.Comment: 7 pages, 3 figure

    How do urban forests compare? Tree diversity in urban and periurban forests of the southeastern US

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    Es necesario comprender cómo las influencias antropogénicas afectan la diversidad forestal urbana y periurbana a escala regional. Este estudio tiene como objetivo comparar la composición de los árboles urbanos y periurbanos a lo largo de un gradiente geográfico, y probar hipótesis sobre la composición de especies y la homogeneidad ecológica. Combinamos datos de bosques urbanos (UF) de ocho ciudades del sureste de los EE. UU. Con datos de bosques periurbanos (PF) del programa de Análisis e Inventario Forestal del Servicio Forestal del USDA. Encontramos que la diversidad de árboles, así como los valores de riqueza de especies observados y estimados, fueron mayores en UF versus PF. El análisis de la estructura del tamaño de la comunidad también indicó una mayor proporción de árboles grandes y un mayor número de especies de árboles no nativas, invasoras y no clasificadas en la UF frente a la PF, independientemente de la ubicación. Tanto el tipo de bosque como la provincia ecológica tuvieron un efecto significativo en la composición de especies de la comunidad, ya que los bosques más cercanos en el espacio son más similares entre sí que los más distantes. Si bien el cambio y el manejo del uso de la tierra se han asociado con la homogeneización ecológica en paisajes dominados por humanos, descubrimos que la composición de las especies era más diferente a lo largo de las líneas latitudinales que entre los tipos de bosque, refutando esta hipótesis, al menos en términos de diversidad de árbolesThere is a need to understand how anthropogenic influences affect urban and periurban forest diversity at the regional scale. This study aims to compare urban and periurban tree composition along a geographic gradient, and test hypotheses about species composition and ecological homogeneity. We paired urban forest (UF) data from eight cities across the southeastern US with periurban forest (PF) data from the USDA Forest Service Forest Inventory and Analysis program. We found that tree diversity, as well as both observed and estimated species richness values were greater in UF versus PF. Community size structure analysis also indicated a greater proportion of large trees and greater numbers of non-native, invasive, and unclassified tree species in the UF versus the PF, regardless of location. Both forest type and ecological province had a significant effect on community species composition, with forests closer together in space being more similar to each other than those more distant. While land use change and management has been associated with ecological homogenization in human dominated landscapes, we found that species composition was more dissimilar along latitudinal lines than compared to between forest types, refuting this hypothesis, at least in terms of tree diversit

    Patients' experiences of brief cognitive behavioral therapy for eating disorders: A qualitative investigation

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    Objective Although it is important to analyze the effectiveness of new therapies, it is also necessary to consider how patients experience them. This is particularly important if we are to maximize treatment acceptability and reduce attrition. This study examined patient experiences of a new 10‐session cognitive‐behavioral therapy (CBT‐T), using a qualitative approach. Method The sample was 17 patients with a diagnosis of bulimia nervosa who had received CBT‐T (including treatment completers and non‐completers) within the previous 2 years. Sample size was determined by saturation of the emergent themes. Responses were analyzed using a six‐step thematic analysis process. Results Rated acceptability and effectiveness of CBT‐T were high. Five themes emerged, with subthemes. The key elements of patient experience of the therapy were: the therapeutic relationship; the nature of the therapy; its challenging but beneficial aspects; ending therapy; and the overall experience of CBT‐T (including comparison with other therapies). Discussion The findings build on the effectiveness research for CBT‐T, suggesting that it is an acceptable therapy that addresses many of the same themes that matter to patients as other therapies. The findings show that patients were positive about CBT‐T relative to other therapies, and offer suggestions as to how CBT‐T might be delivered to emphasize the importance of the time‐limited nature of the therapy
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