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Life History Allocation of Energy to Growth and Reproduction in Gizzard Shad, Dorosoma cepedianum, in North Central TexasFagan, Joseph A. 12 1900 (has links)
Life history allocation of energy to growth and reproduction was determined for female gizzard shad. Absolute caloric energy allocated to eggs increased with age. The relative amount of production energy directed to reproduction increased with age up to 5 years and then decreased. Seasonal variation in lipids was studied. Quantitative changes occurred in ovarian lipids during the reproductive cycle. Carcass lipids varied seasonally. Age of sexual maturity was 3 years. Delayed maturity is attributed to high allocation of energy to growth enabling shad to outgrow intense competition and predation in pre-reproductive ages; there is little competition and predation in reproductive shad. Growth rates and condition factors indicated constant availability of food seasonally.
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Teoria de carteiras e a aloca??o de parques e?licos offshoreSilva, Lana Viviane Linhares da Costa 27 June 2014 (has links)
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Previous issue date: 2014-06-27 / Universidade Federal do Rio Grande do Norte / The consumption of energy on the planet is currently based on fossil fuels. They are responsible
for adverse effects on the environment. Renewables propose solutions for this scenario, but
must face issues related to the capacity of the power supply. Wind energy offshore emerging
as a promising alternative. The speed and stability are greater winds over oceans, but the variability
of these may cause inconvenience to the generation of electric power fluctuations. To
reduce this, a combination of wind farms geographically distributed was proposed. The greater
the distance between them, the lower the correlation between the wind velocity, increasing the
likelihood that together achieve more stable power system with less fluctuations in power generation.
The efficient use of production capacity of the wind park however, depends on their
distribution in marine environments. The objective of this research was to analyze the optimal
allocation of wind farms offshore on the east coast of the U.S. by Modern Portfolio Theory. The
Modern Portfolio Theory was used so that the process of building portfolios of wind energy
offshore contemplate the particularity of intermittency of wind, through calculations of return
and risk of the production of wind farms. The research was conducted with 25.934 observations
of energy produced by wind farms 11 hypothetical offshore, from the installation of 01 simulated
ocean turbine with a capacity of 5 MW. The data show hourly time resolution and covers
the period between January 1, 1998 until December 31, 2002. Through the Matlab R
software,
six were calculated minimum variance portfolios, each for a period of time distinct. Given the
inequality of the variability of wind over time, set up four strategies rebalancing to evaluate
the performance of the related portfolios, which enabled us to identify the most beneficial to the
stability of the wind energy production offshore. The results showed that the production of wind
energy for 1998, 1999, 2000 and 2001 should be considered by the portfolio weights calculated
for the same periods, respectively. Energy data for 2002 should use the weights derived from
the portfolio calculated in the previous time period. Finally, the production of wind energy in
the period 1998-2002 should also be weighted by 1/11. It follows therefore that the portfolios
found failed to show reduced levels of variability when compared to the individual production
of wind farms hypothetical offshore / O consumo de energia no planeta ? atualmente baseado no uso de combust?veis f?sseis. Eles
s?o respons?veis por efeitos negativos sobre o meio-ambiente. As energias renov?veis prop?em
solu??es para esse cen?rio, mas devem encarar quest?es relacionadas ? capacidade de fornecimento
de energia. A energia e?lica offshore desponta como uma alternativa promissora. A velocidade
e estabilidade dos ventos s?o maiores sobre oceanos, mas a variabilidade dos mesmos
pode provocar flutua??es inconvenientes ? gera??o de energia el?trica. Para diminuir isso, uma
combina??o de parques e?licos distribu?dos geograficamente foi proposta. Quanto maior a dist?ncia
entre eles, menor a correla??o entre a velocidade dos ventos, aumentando a probabilidade
de que produzam conjuntamente um sistema de energia mais est?vel, com menos flutua??es da
produ??o de energia. O uso eficiente da capacidade de produ??o dos parques e?licos, entretanto,
depende da distribui??o deles em ambientes mar?timos. O objetivo desta pesquisa foi analisar a
aloca??o ?tima de parques e?licos offshore na costa leste dos EUA, atrav?s da Moderna Teoria
de Carteiras. A Moderna Teoria de Carteiras foi empregada de modo que o processo de constru??o
das carteiras de energia e?lica offshore contemplasse a particularidade da intermit?ncia dos
ventos, atrav?s dos c?lculos de retorno e risco da produ??o dos parques e?licos. A pesquisa foi
desenvolvida com 25.934 observa??es de energia, produzidas por 11 parques e?licos offshore
hipot?ticos, a partir da instala??o simulada de 01 turbina oce?nica com capacidade m?xima de
5 MW. Os dados apresentam resolu??o de tempo hor?ria e cobrem o per?odo entre 01 de janeiro
de 1998 at? 31 de dezembro de 2002. Por meio do software Matlab R
, foram calculadas
seis carteiras de m?nima vari?ncia, cada qual para um per?odo de tempo distinto. Diante da
desigualdade da variabilidade dos ventos no tempo, estabeleceu-se quatro estrat?gias de rebalanceamento
para avaliar o desempenho das carteiras calculadas, o que possibilitou identificar
a mais ben?fica ? estabilidade da produ??o de energia e?lica offshore. Os resultados apontaram
que a produ??o de energia e?lica dos anos de 1998, 1999, 2000 e 2001 deve ser ponderada pelos
pesos das carteiras calculadas nos mesmos per?odos, respectivamente. Os dados de energia
de 2002 devem utilizar os pesos oriundos da carteira calculada no per?odo de tempo anterior.
Por fim, a produ??o de energia e?lica do per?odo entre 1998-2002 deve ser igualmente ponderada
por 1/11. Conclui-se assim que as carteiras encontradas conseguiram demonstrar n?veis
de variabilidade reduzidos quando comparados aos da produ??o individual dos parques e?licos
offshore hipot?ticos
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