952 resultados para yellow perch
Resumo:
The study divides the history of the fishery into five 'regulatory periods': the pre-colonial fishery (pre-1901), the colonial fishery (1901-1963), the post indipendence fishery (1963-1980), the Nile perch 'boom' years (1980-1989), and finally the fishery in the 1990's. Within each of these periods, the nature of and the relationship between, formal and informal regulations differs and changes with time. In the pre-colonial period, the outcome of formal and informal regulations largely sustained the fishery in a productive and species diverse state. However, at no time since then have formal regulations worked, with the result that the nature of production from the fishery changes over time and is dependent on a number of factors, amongst which the most important are effort level increases, technological introductions, species introductions, changes in regional and national job markets, the change from community-based controls to state-based controls within the fishery, and finally, considerable changes to the fish markets.
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This report covers the period April to September, 1989. During this period sampling of invertebrates has concentrated on planktonic animals and those associated with one of the dominant macrophytes in the system, Nuphar lutea, the yellow water lily, since these are particularly important in the diets of larval and juvenile cyprinid fish. A proportion of samples has been partly analysed and some preliminary data are presented here.
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It has been estimated that in England and Wales fresh water covers some 340 square miles of which about one quarter is inhabited mainly by salmon and trout; in Scotland the lakes cover an area of 340 square miles. The principal object of this publication is to make available in handy form some of the methods, especially those involving the use of manures, by which crops of fish from water can be increased. The cultivation of water which this implies may be compared directly to the cultivation of farm land: the conditions for growth are made as favourable as possible, the seed is sown in the form of young fish, and after one or perhaps two growing seasons the crop is harvested. There are however many waters about the country where marketable fish are already available and can be removed without prejudice to, and indeed to the advantage of, sporting fisheries. In such cases it is necessary only to remove the fish and to rely on the natural processes of reproduction of those which are left to repopulate the water. Farming waters in the true sense is the concern of the greater part of this publication; the removal of crops of otherwise unwanted fish is considered in the last two sections on perch trapping and eel fisheries.
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Devido a sua alta incidência, mortalidade e custos elevados, o câncer de mama feminino é considerado um problema de saúde pública no Brasil. Sua etiologia envolve uma interação de diversos fatores denominados de risco os quais podem ser ambientais e genéticos. A história familiar positiva para câncer de mama é um importante fator de risco para o desenvolvimento dessa patologia. Conhecer esses fatores e as medidas de proteção permite que mulheres com risco elevado possam criar estratégias pessoais que venham minimizar os danos causados pela doença. Diante do exposto, o presente estudo tem como objetivos avaliar o nível de conhecimento de mulheres acerca do risco de desenvolverem câncer de mama em decorrência do vínculo familiar com a população portadora desta neoplasia matriculada no Hospital do Câncer III, unidade do Instituto Nacional de Câncer (INCA) especializada no tratamento e controle do câncer de mama, localizada no município do Rio de Janeiro, Brasil; descrever as características sociodemográficas das mulheres familiares de pacientes portadoras de câncer de mama e descrever a história reprodutiva e hormonal, bem como seus hábitos de cuidado com a saúde. Metodologia: trata-se de um estudo exploratório sob a perspectiva quantitativa, transversal e descritiva com 52 mulheres que acompanhavam suas familiares internadas em unidade clínica e cirúrgica do Hospital do Câncer III. A coleta de dados ocorreu no período entre julho e agosto de 2011. A técnica de amostragem adotada foi a não probabilística, intencional Para o cálculo amostral aplicou-se a fórmula de população infinita. Foram selecionadas as seguintes variáveis para compor o estudo: aspectos sociodemográficos, aspectos da vida reprodutiva e hormonal, aspectos de cuidados com a saúde e aspectos de esclarecimento relacionados à patologia/doença. Realizou-se entrevista estruturada com utilização de um formulário composto por 63 questões. A descrição das variáveis foi feita através de frequência simples e porcentagem. Resultados: 61,5% eram filhas, 34,6% eram irmãs e 3,8% eram mães, 40,4% moram no município do Rio de Janeiro, 86,4% encontram-se na faixa etária entre 29 e acima de 51 anos de idade, 32% são pardas, 46,1% apresentavam 2 grau completo, 46,2% são do lar, 15,4% tiveram menarca precoce, 7,7 % tiveram na menopausa tardia, 7,7% fizeram Terapia de Reposição Hormonal, 38,5% nunca engravidaram, 3,8% engravidaram após 30 anos, 3,8% não amamentaram, 42,4% usam anticoncepcional hormonal por mais de 5 anos e 40,4% nunca fizeram descanso ou faz por tempo inferior a 6 meses, 7,7% e 7,6% nunca fizeram e apresenta mais de 24 meses que fizeram exame ginecológico. Quanto ao grau de esclarecimento 34% concordaram com as afirmativas sobre fatores de risco, 65% concordaram com medidas preventivas e os profissionais de saúde foram os que mais transmitiram informação sobre o câncer de mama. Conclusão: ser familiar de primeiro grau associado à falta de esclarecimento sobre a doença torna essas mulheres mais vulneráveis em relação à população geral feminina. Torna-se oportuno para a enfermagem estratégias educativas que visem à promoção da saúde e que contribuam para a modificação do panorama da doença, em razão da detecção mais precoce.
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The optical properties of zirconia films doped with rhodamine 6G and oxazine 725 by the sol-gel process were investigated using spectroscopic ellipsometry (SE). Accurate refractive index n and the extinction coefficient k were determined using a three-oscillator classical Lorentz model in the wavelength range of 300-800 nm. The derived refractive index of dye-doped films exhibited anomalous dispersion in the absorption region. Wavelength tunable output lasing action yellow and near-infrared wavelength region was achieved by DFB configuration using zirconia films doped with R6G and oxazine 725. (c) 2006 Elsevier B.V. All rights reserved.
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We report on space-selective co-precipitation of silver and gold nanoparticles in Ag+, Au3+ co-doped silicate glasses by irradiation of femtosecond laser pulses and subsequent annealing at high temperatures. The color of the irradiated area in the glass sample changed from yellow to red with the increase of the annealing temperature. The effects of average laser power and annealing temperature on precipitation of the nanoparticles were investigated. A reasonable mechanism was proposed to explain the observed phenomena. (c) 2006 Elsevier Ltd. All rights reserved.
Resumo:
采用传统的玻璃熔融法制备了组成为60Bi2O3-20B2O3-15SiO2-5La2O3(mol%)的铋酸盐玻璃, 系统研究了不同工艺过程对玻璃性能的影响. 分析了样品ICP的成分,扫描电镜,X-射线衍射谱, 差热分析和紫外-可见-近红外透过光谱测试. 结果表明:使用刚玉坩埚能提高玻璃的抗析晶稳定性 和透过率,陶瓷坩埚和白金坩埚均受到严重腐蚀,玻璃组分也随之发生很大变化. 当熔制温度从1 100 ℃变化到1 300 ℃时,玻璃的颜色从浅黄色变到深红棕色. 尤其是白金粒子被腐蚀进入玻璃液 后,玻璃中很容易形成纳米颗粒或者团聚形成胶体粒子,在玻璃中形成色散源,加深玻璃的颜色, 降低透过率. 1 300 ℃下,白金粒子起到晶核剂的作用,生成Bi2Pt2O7和BiB3O6晶相,导致玻璃失透.
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In this paper, we report on the multicolor luminescence in oxygen-deficient Tb3+-doped calcium aluminogermanate glasses. A simple method was proposed to control oxygen-deficient defects in glasses by adding metal Al instead of the corresponding oxide (Al2O3), resulting in efficient blue and red emissions from Tb3+-undoped glasses with 300 and 380 nm excitation wavelengths, respectively. Moreover, in Tb3+-doped oxygen-deficient glasses, bright three-color (sky-blue, green or yellow, and red) luminescence was observed with 300, 380, and 395 nm excitation wavelengths, respectively. These glasses are useful for the fabrication of white light-emitting diode (LED) lighting.
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NaYF4: 0.02Er center dot xYb-PVP composite nanofibers with the diameter of similar to 400 nm have been prepared by electrospinning. Field emission scanning electron microscope and X-ray diffraction have been utilized to characterize morphology and structure of the as-prepared electrospun nanofibers. Their up-conversion luminescence is investigated under a 980-nm excitation. Green (538 and 520 nm), red (6-55 nm), and blue (405 nm) emissions are observed in the up-conversion luminescence spectra, and the intensity of these three emissions changes differently with the variety of Yb content, which has been interpreted successfully in this letter. The color of NaYF4: 0.02Er center dot xYb-PVP nanolibers under a 980-nm excitation can be changed from green --> white --> yellow gradually via changing the Yb content.
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This paper reports that the m-plane GaN layer is grown on (200)-plane LiAlO2 substrate by metal-organic chemical vapour deposition (MOCVD) method. Tetragonal-shaped crystallites appear at the smooth surface. Raman measurement illuminates the compressive stress in the layer which is released with increasing the layer's thickness. The high transmittance (80%), sharp band edge and excitonic absorption peak show that the GaN layer has good optical quality. The donor acceptor pair emission peak located at similar to 3.41 eV with full-width at half maximum of 120 meV and no yellow peaks in the photoluminescence spectra partially show that no Li incorporated into GaN layer from the LiAlO2 substrate.
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采用石墨电阻加热的温梯法生长了V:YAG晶体,晶体的不同部位呈现两种不同的颜色:浅绿色和黄褐色.通过对比分析不同颜色V:YAG晶体的室温吸收光谱,推断出石墨发热体高温下扩散出来的C可以起到还原作用,提高晶体中V^3+tetra离子的浓度,同时诱导了F心的形成.在1300℃下,对不同颜色的V:YAG晶体进行真空退火处理,发现处于八面体格位中的V^3+离子在热激发作用下与近邻的四面体格位Al^3+离子存在置换反应,由此产生一定浓度的四面体格位V^3+离子.同时,F心在退火过程中被完全消除,释放出来的自由电子被
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A V:YAG single crystal was grown by the temperature gradient technique (TGT) with graphite-heating elements. The as-grown crystal has different colorations of light green and yellow brown in different parts. Distribution of vanadium in three samples with different colorations was determined by inductively coupled plasma-mass spectrometry. From the absorption spectrum of the yellow-brown part with peaks at 370, 820 and 1320nm, we can deduce that the reducing atmosphere of carbon diffused from the heating elements can increase the concentration of tetrahedral V3+ ions and induce F color centers. All three samples exhibited light-green color after annealing in vacuum or H-2 atmospheres. In the vacuum annealing process, the V3+ ions in tetrahedral positions were enhanced through two methods: one method is the exchanging of octahedral V3+ and tetrahedral Al3+ ions in neighboring sites under thermal excitation, the other is that F color centers were thoroughly eliminated and the escaped free electrons could be captured by V ions with higher valance states to further improve the concentration of tetrahedral V3+ ions. Besides the two mechanisms, the H-2 annealing process greatly improved the V-tetra(3+) ions through the reduction effect of H-2. (c) 2006 Elsevier B.V. All rights reserved.
Resumo:
温度梯度法(TGT)生长的Al2O3晶体因石墨发热体在高温时的挥发和原料中过渡性金属离子的存在,晶体在不同部位呈现不同颜色,一般上部为浅红色,尾部为浅黄绿色,将TGT法生长的Al2O3晶体(Ф110×80mm^3)依次经过高温氧化气氛、高温还原气氛脱碳、去色退火实验,即“两步法”退火实验,晶体变成无色、透明,经测试,Al2O3晶体的完整性、光学透过率和光学均匀性均有显著提高。
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The basis for undertaking this study was to examine factors and potential impacts affecting fish and fishing in relation to low flow drought conditions and what other impacts may arise as a result of further reduced flows resulting from abstraction. The study formed the basis of a three year project to concentrate on effects relating to potable water abstractions at Moor Monkton by YWS. To fully evaluate the possible effects on fisheries the study set out to encompass fish population surveys from fry to adult stock, analysis of angler catch data, reports from anglers and river reports from Environment Agency Fisheries staff. In order to evaluate any effects of drought and abstraction a three year study was instigated to examine fish populations. Fish population surveys were conducted at six sites in which the triennial rolling programme formed the basis of site selection. Multi-method sampling techniques were carried out at several sites in order to evaluate capture efficiency. Roach were prolific above the weir at Linton-on-Ouse, with gudgeon, perch and small bream also well represented. Roach dominated catches on the R.Ouse below Linton, with perch and bleak also relatively abundant. Low flows were not thought to be directly correlated to successful recruitment of coarse fish, rather the associated high temperatures during drought conditions showing a strong positive effect with most species exhibiting growth rates above their long-term average. At this stage in the study there are no clear indications that the drought has caused any deleterious effects to coarse fish populations or marked changes in species composition, with evidence of good recruitment by several species, indicating that the higher temperatures have generally been beneficial to recruitment. However, the indication that dace did not benefit as well as other coarse fish under these conditions may suggest some species are affected more than others. The successful strong recruitment of most coarse fish suggests that, in future, fisheries will be supported by the 1995 year-class.
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Este texto é uma fabulação que cumpre papel de revelar um processo de trabalho em arte ao longo de dois anos. Trata-se de um percurso teórico-poético percorrido a partir da descoberta/invenção de um ateliê de criação em meio a minha residência. Um quadrado de 2x2 metros demarcado por sobreposição = fita amarela. Instaurado em divergentes contextos paisagísticos = casa, quarto de hotel, estúdio de dança, galeria de arte, palco, cidade. Trata de habitar os mesmos friccionando esfera de vivência pessoal e sítio específico de acontecimento. No texto, tem lugar reflexões pessoais a partir do trabalho, articulada a outros artistas (como Lygia Clark, Angel e Klauss Vianna, Antonin Artaud, Yves Klein, Min Tanaka, Tadashi Endo) e teóricos (dentre eles Hannah Arendt e Michel Foucault), compondo diferentes tons de fala produzidos ao longo desse período de trabalho