965 resultados para COUTO, MIA


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Like pages of a "natural coastal diary", successive layers of anoxic varved sediment in the central Santa Barbara Basin have been used by paleoceanographers to reconstruct aspects of past coastal climate. This report focuses on the end of the "Little Ice Age" (15th to 19th century) and on the beginning of this century, a period known to encompass extreme climate excursions and weather events in the Santa Barbara Basin and other parts of Southern California. El Niño events are known to disrupt Southern California's coastal ecosystems and to cause anomalous weather conditions, but El Niño events in Southern California before 1990 have been largely undocumented.

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A participatory on-farm trial was carried out to evaluate the production performance of GIFT (genetically improved farmed tilapia) strain of Oreochmis sp., either alone or with silver barb (Barbodes gonionotus), in six rain-fed freshwater ponds of coastal area. There vvere two treatments; (i) GIFT alone at a stocking density of 24,700/ha (T1) and (ii) 1:1 combination of GIFT and silver barb (T1). Each of the treatments had three replications. A significantly (p

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Grapsid crab Helice tridens latimera inhabiting mangroves, seashores as well as muddy and rocky areas. Ovigerous females were observed from December to May. Juveniles appeared in July and from December to April. In the laboratory they reached 9.50 mm in carapace width 4 months after hatching. It is likely that spawning of this crab occurs throughout the year.

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Effects of different levels of salinity on survival, growth and gonadal development of Genetically Improved Farmed Tilapia (GIFT) were studied under laboratory conditions in glass aquarium, for a period of ten weeks. The initial individual size of the GIFT was 20.23±4.45 and the salinity levels tested were 0, 5, 10, 15 and 20 ppt. The highest survival of 87.5% was found in 0 ppt and the lowest 60.5% in 20 ppt. Though the survival decreased progressively with increased salinity, there were no significant differences (P>0.05) among 0, 5, and 10 ppt. Similar to what has been observed in survival, the specific growth rate (SGR %/day) also decreased as of 1.30, 1.24, 1.08, 0.90 and 0.71, respectively, with the increased salinity of 0, 5, 10, 15 and 20 ppt. The gonadal development was highest in 0 ppt with a GSI value of 3.75 and lowest of 2.01 in 20 ppt. In the second experiment, gonadal development and seed production performance of GIFT in brackishwater condition were investigated for a period of three months. Each of the three fine meshed hapas of 20 square meters made from nylon net was placed in a freshwater (0 ppt) and in a brackish water (10-15 ppt) pond of the Brackishwater Station (BS). GIFT of 65 g average weight from a single cohort were stocked into three hapas at a rate of 2 per m. The male vs female ratio was 1:3. The development of gonad was faster with the higher gonadosomatic index (GSI %) of 3.85 % in freshwater condition than that of 2.73 % in brackish water. Within three months of the study period, a total of 70,510 and 44,250 GIFT fry were produced respectively, in freshwater and brackishwater conditions. Finally under third experiment, a participatory on-farm trial was carried out to evaluate the production performance of GIFT in monoculture and in polyculture with silver barb in coastal freshwater pond conditions. Nine ponds were selected for three treatment combinations of GIFT monoculture (T1), GIFT and silver barb polyculture (T2), and silver barb monoculture (T3). The ponds have been stocked in April, 05 at a density of 25,000 fry per ha. Fishes were fed with rice bran at the rate of 6% bw per day. In one month culture period, GIFT attained an average weight of 16.27 g in monoculture and 17.23 g in polyculture, against an average stocking weight of 0.37 g. Silver barb reached an average weight of 16.62 g in polyculture with GIFT and 10.01 g in monoculture, against an average stocking weight of 3.79 g.

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Mud crablings, Scylla sp. were reared, for a period of six weeks in fiberglass aquarium under laboratory conditions, to determine the effect of four different stocking densities of 1, 2, 3 and 4 crabling/l of water on their survival and growth. Salinity of water was maintained at 25 ppt throughout the rearing period. Stocking rates of 1, 2, and 3 crabling/l resulted in a similar (p>0.05) survival rates of 75, 74, and 83.5%, respectively, that of 4 crabling/l resulted in significantly lower (p<0.05) survival rate of 56%. No significant difference was observed among different stocking densities in average growth of carapace length (CL), carapace width (CW) and body weight (BW).

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Different problems have been created on the downstream territory, especially on Bheramara on the bank of mighty river Padma. The study is preferred to assess the impacts on river flow of Ganges water, and on fisheries, agriculture, irrigation, groundwater, livelihood, and biodiversity because of Farakka Barrage. Information were collected from various respondents among which 42% is farmer, 12% is fisherman, 36% is businessman and 10% is service holder. It is evident from this study that 65% of crops production were directly affected by Farakka Barrage, in which 34% crops were damaged due to scarcity of water, lowering the ground water level, less access to rainwater, etc. and 66% crops were invent for increasing char land, increasing soil fertility for the use of agrochemicals. Irrigation has been adversely affected because of 35% insufficient flow of water and 65% lowering the ground water level.

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The Southeast Fisheries Science Center (SEFSC) initiated annual, vessel-based visual sampling surveys of northern Gulf of Mexico marine mammals in 1990 and conducted a similar survey in U.S. Atlantic Exclusive Economic Zone (EEZ) waters from Miami, Florida, to Cape Hatteras, North Carolina, in 1992. The primary goal of these surveys was to meet Marine Mammal Protection Act requirements for estimating abundance and monitoring trends of marine mammal stocks in United States waters. The surveys were designed to collect: 1) marine mammal sighting data to estimate abundance and to determine distribution and diversity; and 2) environmental data to evaluate factors which may affect the distribution, abundance and diversity of marine mammals. The preliminary analyses for abundance estimation from the 1990-1993 surveys are presented in this report.

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The Southeast Fisheries Science Center (SEFSC) initiated annual, vessel-based visual sampling surveys of northern Gulf of Mexico marine mammals in 1990. The primary goal of these surveys was to meet Marine Mammal Protection Act requirements for estimating abundance and monitoring trends of marine mammal stocks in United States waters. The surveys were designed to collect: 1) marine mammal sighting data to estimate abundance and to determine distribution and diversity; and 2) environmental data to evaluate factors which may affect the distribution, abundance and diversity of marine mammals. The analyses for abundance estimation from the 1991-1994 surveys are presented in this report.

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1.热可交联聚酰亚胺/高性能热塑性树脂共混体系的研究聚苯硫醚[Poly(phenylene sulfide),PPS]是由刚性结构的苯环和柔性的硫醚连接起来,交替排列构成的线性高分子化合物,具有高的热稳定性、良好的耐化学药品性、优良的电绝缘性、耐老化性和阻燃性等综合性能优异的高性能树脂。聚醚矾〔Poly(ether sulfone),PES]是一种非结晶性的热塑性工程塑料一,具有优异的热稳定性、耐高温蠕变性及优异的物理机械性能。其高的玻璃化转变温度(Tg=225℃),使其可以在较高温度下作为结构材料使用。本论文研究了PPS/PES二元共混物的热性能和动态力学性能,并以热可控交联的低分子量多官能单体PMR-POI(聚醚酰亚胺)为界面增强剂,分别研究了POI与PPS、PES之间的接枝和/或交联反应,POI对PPS结晶行为的影响,POI对PES分子运动的影响和POI对PPS/PES共混体系的界面增强。主要结果如下:1.PPS/PES共混物相容性的特征在于选择性的部分相容,少量的非晶PPS分子可以扩散进入PES相区,相反的扩散过程则不会发生。2.PPS/PES共混物的热学性质和动态力学性能主要受连续相的控制。3.PPS相的性能主要受其结晶度的影响,因此能够改变其结晶度的因素均会改变PPS相的性质。4.光谱学和流变的证据表明,POI同PES,PPs共混过程中有接枝反应发生,分子链增长,分子量加大。这种接枝和/或交联反应的程度是热可控的。5.POI是PPS的增塑剂,成核剂和扩链剂,与POI共混使得PPS结晶速率增加,平衡熔点上升,表面折叠自由能降低。6;在PES/POI体系中Pol对PEs起到了增塑的作用,Tg降低,经高温热处理后Tg上升。因此,POI对PES性能的影响也是热可控的。7.PMR-POI能够在PPS/PES共混体系中有效地扩散并起到了降低分散相粒子的尺寸、增强界面的作用。它是该共混体系的有效界面增强剂。8."高温退火既能够提高扩散速率也能够提高反应速率;二者相互竞争。2.马来酸配封端溉碳酸丙撑酯的研究二氧化碳与环氧丙烷交替共聚物(polypropylene careonate,PPC)是由二氧化碳活化并与环氧丙烷共聚而成的一类可完全生物降解的新型高分子材料,具有巨大的潜在应用价值。本论文讨论了马来酸配封端的聚碳酸丙撑酯(MA-PPC)和未封端的PPC的粘弹性、流变行为以及热降解和热分解行为,并得出如下结论:1.马来酸配封端抑制了PPC解拉链式的热分解和无规链断裂热降解,PPC的热稳定性和力学性能得到提高。2.PPC和MA-PPC在玻璃化转变温度有相似的自由体积分数,PPC的Tg比MA-PPC稍低。虽然PPC和MA-PPC玻璃化转变表观活化能E。和平均松弛时间T随温度升高单调降低,但PPC的分子运动对温度更敏感,而MA-PPC较稳定。马来酸配封端改变了PPC分子运动的特征及松弛行为,许多实验证据证明,这是由于封端后的PPC大分子链间的相互作用增强及分子链缠结密度增加。3.MA-PPC在70℃左右会发生脱水,实现大分子偶联反应并得到变温红外光谱、分子量成倍增加及线膨胀数据的有力支持。4.用零剪切粘度几。的方法测得PPC及MA-PPC加工过程中的热降解温度,它们分别为150℃和175℃,在此温度以上,η0降低速率的增加归因于大分子的主链断裂以及解拉链反应。5.测得了PPC的临界缠结分子量,它几乎是MA-PPC相应值(6613)的3倍。这表明马来酸配封端不仅改善了PPC的熔体弹性,而且也大大增强了PPC的缠结密度以及分子链间的相互作用。6.在本实验条件下在氮气和空气的气氛中,MA-PPC同PPC的热降解和热分解行为几乎一致,即在PPc的加土过程可以忽略氧气对其的影响。7.虽然MA-PPC的玻璃化温度在40℃左右,但在40℃-120℃的温度区间内,MA-PPC达不到粘流状态。8.没有剪切力时在120℃-150℃,30分钟内,MA-PPC几乎没有降解,在静态条件下,低于170℃时,MA-PPC的解拉链式降解是十分轻微的,当温度超过170℃,PPC降解相当严重。9.在热机械力存在的情况下,发生无规断链的机会增加,无规断链又会加速解拉链降解,因此实际加工中的加工窗口比静态下窄,MIA-PPC的加工窗口应为130℃-160℃。10.MA-PPC的热分解过程是一步完成的,热分解温度随升温速率的加快而提高,并计算出热分解的表观活化能为623.3KJ/mol。

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Para romper o processo verticalizado que impõe um modelo produtivo para o campo sem a participação dos principais interessados, foi proposto, como parte do projeto ?Inserção e Competitividade do Agricultor Familiar do Extremo Sul da Bahia no Agronegócio da Mandioca e do Abacaxi?, o uso de metodologias participativas, visando à melhoria do processo de socialização das tecnologias e de construção do conhecimento. Nos assentamentos Lajedo Bonito e São Miguel, localizados nos municípios de Guaratinga e Porto Seguro, respectivamente, foram utilizados o Diagnóstico Rural Participativo e de grupo focal, para identificar as características dos grupos relativas às formas de organização, sistema produtivo, organização da produção e alocação de mão-de-obra, dentre outros fatores. Foram realizadas incursões nos lotes para reconhecimento dos sistemas de produção adotados nas unidades familiares. A partir do diagnóstico, foi realizado o planejamento participativo das comunidades. Em ambos os processos foram identificadas necessidades de melhorias estruturais e estruturantes, relacionadas, principalmente, ao processo produtivo e às condições sociais. Posteriormente aos diagnósticos, foram instaladas nos assentamentos áreas com mandioca e abacaxi, nas quais os agricultores praticaram diferentes formas de cultivo com especial atenção às tecnologias e novos processos propostos. Após três anos de condução dos trabalhos em campo com os agricultores, as metodologias participativas mostraram-se como ferramentas eficientes no processo de autoconhecimento das comunidades assentadas, permitindo não só a identificação dos problemas, mas também o seu dimensionamento e a proposição de soluções. A instalação de unidades de observação nas áreas dos agricultores constitui-se numa ferramenta clássica para a oferta de tecnologias. No entanto, para que os novos conhecimentos sejam consolidados, fazem-se necessários tanto o acompanhamento regular pela assistência técnica como o financiamento das atividades agrícolas, sem o que o aprendizado pode ser perdido ao longo do tempo.

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1984

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2002