989 resultados para biological efficiency
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By introducing the OneFile e–portfolio system, the Motor Vehicle department at Huntingdonshire Regional College has revolutionised its teaching and learning delivery, improved organisational efficiency, and helped students achieve qualifications quicker. Bundles of paper have been scrapped, students can now upload video and audio as reflective evidence, and assessors no longer have to go on unnecessary visits to collect papers and signatures. What's more, the department has saved time and money, diversified learning and made an impact on its carbon footprint.
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During the 18th Annual 2008 SAIL meeting at the Smithsonian Tropical Research Institute in Panama, a suggestion was made for the need to digitize and make available through the Aquatic Commons some of the early documents related to the U.S. biological survey of Panama from 1910 to 1912. With SAIL’s endeavor, a new digital project was born and this presentation describes its process, beginning to final product. The main source consulted for determining copyright clear publications was: Heckadon-Moreno. 2004. Naturalists on the Isthmus of Panama: A hundred years of natural history on the biological bridge of the Americas. 1st English ed. Smithsonian Tropical Research Institute, Panama City, Republic of Panama. (Document contains 26 slides)
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Habitat mapping and characterization has been defined as a high-priority management issue for the Olympic Coast National Marine Sanctuary (OCNMS), especially for poorly known deep-sea habitats that may be sensitive to anthropogenic disturbance. As a result, a team of scientists from OCNMS, National Centers for Coastal Ocean Science (NCCOS), and other partnering institutions initiated a series of surveys to assess the distribution of deep-sea coral/sponge assemblages within the sanctuary and to look for evidence of potential anthropogenic impacts in these critical habitats. Initial results indicated that remotely delineating areas of hard bottom substrate through acoustic sensing could be a useful tool to increase the efficiency and success of subsequent ROV-based surveys of the associated deep-sea fauna. Accordingly, side scan sonar surveys were conducted in May 2004, June 2005, and April 2006 aboard the NOAA Ship McArthur II to: (1) obtain additional imagery of the seafloor for broader habitat-mapping coverage of sanctuary waters, and (2) help delineate suitable deep-sea coral/sponge habitat, in areas of both high and low commercial-fishing activities, to serve as sites for surveying-in more detail using an ROV on subsequent cruises. Several regions of the sea floor throughout the OCNMS were surveyed and mosaicked at 1-meter pixel resolution. Imagery from the side scan sonar mapping efforts was integrated with other complementary data from a towed camera sled, ROVs, sedimentary samples, and bathymetry records to describe geological and biological (where possible) aspects of habitat. Using a hierarchical deep-water marine benthic classification scheme (Greene et al. 1999), we created a preliminary map of various habitat polygon features for use in a geographical information system (GIS). This report provides a description of the mapping and groundtruthing efforts as well as results of the image classification procedure for each of the areas surveyed. (PDF contains 60 pages.)
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The Olympic Coast National Marine Sanctuary (OCNMS) continues to invest significant resources into seafloor mapping activities along Washington’s outer coast (Intelmann and Cochrane 2006; Intelmann et al. 2006; Intelmann 2006). Results from these annual mapping efforts offer a snapshot of current ground conditions, help to guide research and management activities, and provide a baseline for assessing the impacts of various threats to important habitat. During the months of August 2004 and May and July 2005, we used side scan sonar to image several regions of the sea floor in the northern OCNMS, and the data were mosaicked at 1-meter pixel resolution. Video from a towed camera sled, bathymetry data, sedimentary samples and side scan sonar mapping were integrated to describe geological and biological aspects of habitat. Polygon features were created and attributed with a hierarchical deep-water marine benthic classification scheme (Greene et al. 1999). For three small areas that were mapped with both side scan sonar and multibeam echosounder, we made a comparison of output from the classified images indicating little difference in results between the two methods. With these considerations, backscatter derived from multibeam bathymetry is currently a costefficient and safe method for seabed imaging in the shallow (<30 meters) rocky waters of OCNMS. The image quality is sufficient for classification purposes, the associated depths provide further descriptive value and risks to gear are minimized. In shallow waters (<30 meters) which do not have a high incidence of dangerous rock pinnacles, a towed multi-beam side scan sonar could provide a better option for obtaining seafloor imagery due to the high rate of acquisition speed and high image quality, however the high probability of losing or damaging such a costly system when deployed as a towed configuration in the extremely rugose nearshore zones within OCNMS is a financially risky proposition. The development of newer technologies such as intereferometric multibeam systems and bathymetric side scan systems could also provide great potential for mapping these nearshore rocky areas as they allow for high speed data acquisition, produce precisely geo-referenced side scan imagery to bathymetry, and do not experience the angular depth dependency associated with multibeam echosounders allowing larger range scales to be used in shallower water. As such, further investigation of these systems is needed to assess their efficiency and utility in these environments compared to traditional side scan sonar and multibeam bathymetry. (PDF contains 43 pages.)
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A basic analysis of sources, dates, authors for an Environmental Science Laboratory based at waters edge. (22 powerpoint slides)
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Information on the biology, fishery resources, explotiation patterns, management, and conservation status of two species of grouper-the Nassau grouper, Epinephelus striatus, and the jewfish, Epinephelus itajara-is compiled, reviewed, and analyzed. (PDF file contains 68 pages.)
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ENGLISH: Since the inception of the Inter-American Tropical Tuna Commission in 1950, one of the primary tasks of its scientific staff has been the collection and analysis of the statistics of total catch, effort expended in obtaining this catch, and the apparent abundance of yellowfin tuna (Neothunnus macropterus) and the skipjack tuna (Katsuwonus pelamis) in the Eastern Pacific Ocean. A concentrated effort by the staff during 1951 and 1952 resulted in the compilation of a series of historical data on the catch and catch-per-effort of tropical tunas for the years 1934-1950, and in the establishment of a detailed logbook system to monitor the current activities of the tuna fleets. Schaefer (1953) and Shimada and Schaefer (1956) have reviewed in detail the methods of collection and analysis of these data. Further studies, based on these and subsequently collected records, are contained in publications by Schaefer (1957), Shimada (1958), Alverson (1959, 1960), Griffiths (1960) and Calkins (1961). SPANISH: Desde que la Comisión Interamericana del Atún Tropical comenzó sus funciones en 1950, entre las más importantes tareas de su personal científico incluyó la recolección y análisis de las estadísticas de la captura total, del esfuerzo empleado en obtener esta captura y de la abundancia aparente de los atunes aleta amarilla (Neothunnus macropterus) y barriletes (Katsutvonus pelamis) en el Océano Pacífico Oriental. El concentrado esfuerzo del personal científico de la Comisión durante 1951 y 1952 dió como resultado la compilación de una serie de datos históricos sobre la captura de atunes tropicales y sobre la captura según el esfuerzo durante los años 1934 a 1950, así como el establecimiento de un sistema detallado de registro de las anotaciones en los cuadernos de bitácora para vigilar las actividades diarias de las flotas atuneras. Schaefer (1953) y Shimada y Schaefer (1956) han expuesto detalladamente los métodos de recolección y análisis de dichos datos. Otros estudios, basados en estos registros y en los recolectados posteriormente, se encuentran en las publicaciones de Schaefer (1957), Shimada (1958), Alverson (1959, 1960), Griffiths (1960) y Calkins (1961).
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ENGLISH: An average of 78 m. of water was vertically displaced by wind-driven upwelling during the dry season (January-April) in Panama Bay at the head of the Gulf of Panama. The standing crop of phytoplankton and its productivity were significantly greater during the months of upwelling than during the rainy season. Equivalent results were found by three different methods used to calculate photosynthesis: direct measurement with radiocarbon; increase of dissolved oxygen in the water column; and decrease of phosphate-phosphorus in the water column. About 90 g. of carbon per square meter of sea surface were fixed by the phytoplankton during each upwelling season (January-April) and about 90 g. of carbon were fixed during each rainy season (May-December) resulting in an annual production of about 180 g. of carbon per square meter of sea surface SPANISH: Un promedio de 78 m. de agua fué desplazado verticalmente por la fuerza de los vientos que ocasionan el fenómeno conocido por afloramiento durante la estación seca (enero a abril) en la Bahía de Panamá, a la cabeza del Golfo de Panamá. La cosecha estable de fitoplancton y su productividad fueron significativamente mayores durante los meses de afloramiento, que durante la estación lluviosa. Se obtuvieron resultados equivalentes por medio de tres diferentes métodos usados para calcular la fotosíntesis: medición directa con radiocarbono, aumento del oxígeno disuelto en la columna de agua, y disminución del fosfato-fósforo en la columna de agua. Por medio del fitoplancton durante cada estación de afloramiento (enero-abril), se fijaron alrededor de 90 g. de carbono por metro cuadrado de la superficie del mar, y durante cada estación lluviosa (mayo-diciembre) se fijaron 90 g. de carbono lo que resulta en una producción anual de aproximadamente 180 g. de carbono por metro cuadrado de la superficie del mar.
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ENGLISH:The present paper is principally concerned with the geographic distribution of the standing crop and production of phytoplankton at the surface of the eastern Pacific, east of 130°W and between 10°N and 33°S, as reflected by recently collected data. In addition we discuss some of the more obvious, general relationships among thermocline topography, nutrient concentration, and the various trophic levels from primary production to fish production. The limited data do not allow a seasonal study. We have therefore mapped all of the data together regardless of the time of collection, but do not wish to imply that the physical, chemical and biological system is without seasonal or periodic change. SPANISH:Como lo reflejan los datos recientemente recolectados, el presente trabajo está dedicado principalmente a la distribución geográfica de las cosechas estables y a la producción del fitoplancton en la superficie del Pacífico Oriental, al este de los 130°W y entre los 10°N y 33°S. Además discutimos algunas de las relaciones generales más obvias entre la topografía de la termoclina, la concentración de los nutrientes, y los varios niveles tróficos, desde la producción primaria hasta la producción de los peces. Los datos limitados no permiten un estudio estacional. Por lo tanto, hemos combinado todos los datos no tomando en cuenta el tiempo de la recolección, pero no queremos implicar que no existen cambios estacionales o periódicos en el sistema físico, químico y biológico.
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Fundamentally, action potentials in the squid axon are consequence of the entrance of sodium ions during the depolarization of the rising phase of the spike mediated by the outflow of potassium ions during the hyperpolarization of the falling phase. Perfect metabolic efficiency with a minimum charge needed for the change in voltage during the action potential would confine sodium entry to the rising phase and potassium efflux to the falling phase. However, because sodium channels remain open to a significant extent during the falling phase, a certain overlap of inward and outward currents is observed. In this work we investigate the impact of ion overlap on the number of the adenosine triphosphate (ATP) molecules and energy cost required per action potential as a function of the temperature in a Hodgkin–Huxley model. Based on a recent approach to computing the energy cost of neuronal action potential generation not based on ion counting, we show that increased firing frequencies induced by higher temperatures imply more efficient use of sodium entry, and then a decrease in the metabolic energy cost required to restore the concentration gradients after an action potential. Also, we determine values of sodium conductance at which the hydrolysis efficiency presents a clear minimum.
High power and spectral efficiency coded digital modulation schemes for nonlinear satellite channels
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We compare results of bottom trawl surveys off Washington, Oregon, and California in 1977, 1980, 1983, and 1986 to discern trends in population abundance, distribution, and biology. Catch per unit of effort, area-swept biomass estimates, and age and length compositions for 12 commercially important west coast groundfishes are presented to illustrate trends over the lO-year period. We discuss the precision, accuracy, and statistical significance of observed trends in abundance estimates. The influence of water temperature on the distribution of groundfishes is also briefly examined. Abundance estimates of canary rockfish, Sebastes pinniger, and yellowtail rockfish, S. Jlavidus, declined during the study period; greater declines were observed in Pacific ocean perch, S. alutus, lingcod, Ophiodon elongatus, and arrowtooth flounder, Atheresthes stomias. Biomass estimates of Pacific hake, Merluccius productus, and English, rex, and Dover soles (Pleuronectes vetulus, Errex zachirus, and Microstomus pacificus) increased, while bocaccio, S. paucispinis, and chilipepper, S. goodei, were stable. Sablefish, Anoplopoma fimbria, biomass estimates increased markedly from 1977 to 1980 and declined moderately thereafter. Precision was lowest for rockfishes, lingcod, and sablefish; it was highest for flatfishes because they were uniformly distributed. The accuracy of survey estimates could be gauged only for yellowtail and canary rockfish and sablefish. All fishery-based analyses produced much larger estimates of abundance than bottom trawl surveys-indicative of the true catchability of survey trawls. Population trends from all analyses compared well except in canary rockfish, the species that presents the greatest challenge to obtaining reasonable precision and one that casts doubts on the usefulness of bottom trawl surveys for estimating its abundance. (PDF file contains 78 pages.)
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Information on the biology and fisheries of cobia, Rachycentron canadum, is compiled and reviewed in the FAD species synopsis style. Topics include taxonomy, morphology, distribution, reproduction, pre-adult and adult stages, food, growth, migration, population characteristics, and various aspects of exploitation. Data and information were obtained from unpublished as well as published sources. Cobia, the only species in the family Rachycentridae, is a migratory pelagic fish that occurs in tropical and subtropical seas of the world, except in the central and eastern Pacific Ocean. In the western Atlantic Ocean, spawning occurs during the warm months. Eggs and larvae are planktonic. Females grow faster than males: at 1 year, females are 36 cm FL and 0.4 kg; at 4 years, 99 cm and 11 kg; and at 8 years, 137 cm and 31 kg. Comparable data for males are: at 1 year, 31 cm and 0.3 kg; 4 years, 82 cm and 6 kg; and 8 years, 108 cm and 15 kg. Sexual maturity is attained by males at about 52 cm FL in their second year and by females at about 70 cm in their third year. Fecundity for females 100-125 cm FL varies from 1.9 to 5.4 million eggs. Cobia favor crustaceans for food, but will feed on other invertebrates and fishes as well. They attain a maximum size of over 60 kg. Cobia are fished both commercially and recreationally. Commercially, they are usually caught incidentally in both hook-and-Iine and net fISheries. In the United States, which ranks behind Pakistan, Mexico, and the Philippines in commercial production of cobia, recreational landings exceed commercial landings by more than ten-fold. (PDF file contains 32 pages.)
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Acomprehensive description of the Massachusetts coastal lobster (Homarus americanus) resou,rce was obtained by sampling commercial catches coastwide at sea and at dealerships between 1981 and 1986. Acommercial lobster sea-sampling program, wherein six coastal regions were sampled monthly, with an areal and temporal data weighting design, was the primary source of data. An improved index of catch per trap haul/set-over-day was generated by modeling the relationship between catch and immersion time and standardizing effort. This 6-year time-series of mean annual catch rates tracked closely the landings trend for territorial waters. During the study period there was a gradual increase in indices of exploitation and total annual mortality which corresponded to a gradual decline in mean carapace length of marketable lobster. The frequency of culls escalated from 10.0% in 1981 to 20.9% in 1986, while the percentage of lobster found dead in traps was consistently less than 1%. The sex ratio (%F:%M) was significantly different from 50:50 and approximated a 60:40 relationship during the study period. Male and female weight-length relationships were significantly different. Females weighed more than males at smaller sizes and less than males at larger sizes. A north-south clinal trend was evident wherein lobster north of Cape Cod weighed less at length than those from regions south of Cape Cod. Functional size-maturity relationships were developed for female lobster by staging cement gland development. Proportions mature at size represent more realistic values than those obtained by analyses of percent of females ovigerous. Regional variation occurred in most of the parameters studied. Three lobster groups, differing in major population descriptors, are defined by our data.(PDF file contains 28 pages.)
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This study examined the efficiency of fish diversion and survivorship of diverted fishes in the San Onofre Nuclear Generating Station Fish Return System in 1984 and 1985. Generally, fishes were diverted back to the ocean with high frequency, particularly in 1984. Most species were diverted at rates of 80% or more. Over 90% of the most abundant species, Engraulis mordax, were diverted. The system worked particularly well for strong-swimming forms such as Paralobrax clothratus, Atherinopsis californiensis, and Xenistius californiensis, and did not appreciably divert weaker-swimming species such as Porichthys notatus, Heterostichus rostratus, and Syngnathus sp. Return rates of some species were not as high in 1985 as in 1984. Individuals of most tested species survived both transit through the fish return system and 96 hours in a holding net. Some species, such as E. mordox, X. californiensis, and Umbrina roncador, experienced tittle or no mortality. Survivorship of Seriphus politus was highly variable and no Anchoa delicatissima survived. (PDF file contains 22 pages.)