995 resultados para 7140-220
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To be in compliance with the Endangered Species Act and the Marine Mammal Protection Act, the United States Department of the Navy is required to assess the potential environmental impacts of conducting at-sea training operations on sea turtles and marine mammals. Limited recent and area-specific density data of sea turtles and dolphins exist for many of the Navy’s operations areas (OPAREAs), including the Marine Corps Air Station (MCAS) Cherry Point OPAREA, which encompasses portions of Core and Pamlico Sounds, North Carolina. Aerial surveys were conducted to document the seasonal distribution and estimated density of sea turtles and dolphins within Core Sound and portions of Pamlico Sound, and coastal waters extending one mile offshore. Sea Surface Temperature (SST) data for each survey were extracted from 1.4 km/pixel resolution Advanced Very High Resolution Radiometer remote images. A total of 92 turtles and 1,625 dolphins were sighted during 41 aerial surveys, conducted from July 2004 to April 2006. In the spring (March – May; 7.9°C to 21.7°C mean SST), the majority of turtles sighted were along the coast, mainly from the northern Core Banks northward to Cape Hatteras. By the summer (June – Aug.; 25.2°C to 30.8°C mean SST), turtles were fairly evenly dispersed along the entire survey range of the coast and Pamlico Sound, with only a few sightings in Core Sound. In the autumn (Sept. – Nov.; 9.6°C to 29.6°C mean SST), the majority of turtles sighted were along the coast and in eastern Pamlico Sound; however, fewer turtles were observed along the coast than in the summer. No turtles were seen during the winter surveys (Dec. – Feb.; 7.6°C to 11.2°C mean SST). The estimated mean surface density of turtles was highest along the coast in the summer of 2005 (0.615 turtles/km², SE = 0.220). In Core and Pamlico Sounds the highest mean surface density occurred during the autumn of 2005 (0.016 turtles/km², SE = 0.009). The mean seasonal abundance estimates were always highest in the coastal region, except in the winter when turtles were not sighted in either region. For Pamlico Sound, surface densities were always greater in the eastern than western section. The range of mean temperatures at which turtles were sighted was 9.68°C to 30.82°C. The majority of turtles sighted were within water ≥ 11°C. Dolphins were observed within estuarine waters and along the coast year-round; however, there were some general seasonal movements. In particular, during the summer sightings decreased along the coast and dolphins were distributed throughout Core and Pamlico Sounds, while in the winter the majority of dolphins were located along the coast and in southeastern Pamlico Sound. Although relative numbers changed seasonally between these areas, the estimated mean surface density of dolphins was highest along the coast in the spring of 2006 (9.564 dolphins/km², SE = 5.571). In Core and Pamlico Sounds the highest mean surface density occurred during the autumn of 2004 (0.192 dolphins/km², SE = 0.066). The estimated mean surface density of dolphins was lowest along the coast in the summer of 2004 (0.461 dolphins/km², SE = 0.294). The estimated mean surface density of dolphins was lowest in Core and Pamlico Sounds in the summer of 2005 (0.024 dolphins/km², SE = 0.011). In Pamlico Sound, estimated surface densities were greater in the eastern section except in the autumn. Dolphins were sighted throughout the entire range of mean SST (7.60°C to 30.82°C), with a tendency towards fewer dolphins sighted as water temperatures increased. Based on the findings of this study, sea turtles are most likely to be encountered within the OPAREAs when SST is ≥ 11°C. Since sea turtle distributions are generally limited by water temperature, knowing the SST of a given area is a useful predictor of sea turtle presence. Since dolphins were observed within estuarine waters year-round and throughout the entire range of mean SST’s, they likely could be encountered in the OPAREAs any time of the year. Although our findings indicated the greatest number of dolphins to be present in the winter and the least in the summer, their movements also may be related to other factors such as the availability of prey. (PDF contains 28 pages)
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Parte 1 - Atos do Poder Legislativo
Resumo:
A obra De orbis sitv (descrição do mundo), também chamada De chorographia (corografia), foi escrita em três partes, por volta de 43 d.C. Situa a Terra no centro do universo e descreve regiões, costumes e artes da África, Europa e Ásia, sem contudo detalhar suas distâncias e sistemas administrativo. É o único tratado de geografia da Antiguidade escrito em latim clássico. Esta edição traz extensos comentários de Joaquim Vadiano e observações do teólogo João Camerti e de Rodolfo Agrícola.
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This study analyzed species richness, distribution, and sighting frequency of selected reef fishes to describe species assemblage composition, abundance, and spatial distribution patterns among sites and regions (Upper Keys, Middle Keys, Lower Keys, and Dry Tortugas) within the Florida Keys National Marine Sanctuary (FKNMS) barrier reef ecosystem. Data were obtained from the Reef Environmental Education Foundation (REEF) Fish Survey Project, a volunteer fish-monitoring program. A total of 4,324 visual fish surveys conducted at 112 sites throughout the FKNMS were used in these analyses. The data set contained sighting information on 341 fish species comprising 68 families. Species richness was generally highest in the Upper Keys sites (maximum was 220 species at Molasses Reef) and lowest in the Dry Tortugas sites. Encounter rates differed among regions, with the Dry Tortugas having the highest rate, potentially a result of differences in the evenness in fishes and the lower diversity of habitat types in the Dry Tortugas region. Geographic coverage maps were developed for 29 frequently observed species. Fourteen of these species showed significant regional variation in mean sighting frequency (%SF). Six species had significantly lower mean %SF and eight species had significantly higher mean %SF in the Dry Tortugas compared with other regions. Hierarchical clustering based on species composition (presence-absence) and species % SF revealed interesting patterns of similarities among sites that varied across spatial scales. Results presented here indicate that phenomena affecting reef fish composition in the FKNMS operate at multiple spatial scales, including a biogeographic scale that defines the character of the region as a whole, a reef scale (~50-100 km) that include meso-scale physical oceanographic processes and regional variation in reef structure and associated reef habitats, and a local scale that includes level of protection, cross-shelf location and a suite of physical characteristics of a given reef. It is likely that at both regional and local scales, species habitat requirements strongly influence the patterns revealed in this study, and are particularly limiting for species that are less frequently observed in the Dry Tortugas. The results of this report serve as a benchmark for the current status of the reef fishes in the FKNMS. In addition, these data provide the basis for analyses on reserve effects and the biogeographic coupling of benthic habitats and fish assemblages that are currently underway. (PDF contains 61 pages.)
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本文针对带椭球封头的爆炸容器,黑索今(RDX)在中心处的爆炸用点爆炸模型描述,利用四阶Runge-Kutta法求解一组常微分方程得到爆炸近场的自相似解。采用有限体积形式的PPM格式求解轴对称Euler方程,得到了容器内冲击波传播及其演化的图象。以计算得到的冲击载荷为基础,修改HONDO程序,壳体弹塑性模型采用J_2流动理论描述。对冲击波和壳体的耦合作用进行了初步的数值研究。计算结果表明:容器内爆炸冲击波和壳体中应力波的传播及其演化与物理上的定性分析结果是一致的。由于应力波传播速度较冲击波快,因此,在冲击波未到达的静止流场,流场出现扰动声波,并向中心传播。封头顶点附近出现最大变形。在中等载荷作用下,可忽略壳体变形对流场的影响。
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目录
- 访罗湖 忆当年[李佩]
- 怀念同窗益友郭永怀教授[钱伟长]
- 郭永怀追求科学、为国献身的一生[洪友士]
- 深深怀念为核盾牌献身的著名科学家--郭永怀先生 中国工程物理研究院
- 深切怀念郭永怀教授的奠基性贡献 中国空气动力研究与发展中心
- 胸怀长江长城 心系国家安危--纪念我国核防护工程奠基人郭永怀先生[周丰峻]
- 缅怀我们的首任系主任--郭永怀教授[辛厚文 马兴孝 俞书勤 何天敬]
- 科学和技术结合的典范--纪念郭永怀先生诞辰九十周年[郑哲敏 李家春]
- 怀念与感激[俞鸿儒]
- 继承先师遗愿,谈我所冲击动力学的发展--纪念郭永怀副院长诞辰九十周年[陈裕泽]
- 英名长存--纪念郭永怀副院长诞辰九十周年[沈中毅]
- 郭永怀与我国导弹弹头再入气动物理研究[魏叔如]
- 科研工作引路人--纪念郭永怀九十诞辰[胡在军]
- 科技楷模,引路良师--怀念敬爱的郭永怀副院长[朱竟洪 郑百瑛]
- 七律 永怀永怀郭老师[董务民]
- 留得春晖映核魂--怀念我们的好领导好老师郭永怀同志[孙德纶 张克才]
- 难以忘怀--忆郭永怀副院长事迹点滴[孙天雄]
- 研究工作与工程技术工作之间的关系[谈庆明]
- 忆敬爱的郭永怀老师[张兆顺 呼和敖德]
- 根深叶茂 厚积薄发--追忆恩师郭永怀先生教诲我打好基础[严宗毅]
- 力学前辈,科德风范[徐友钜]
- 领导的楷模 学者的典范 青年的导师--怀念郭永怀副院长[于长勤]
- 怀念郭永怀副院长[陈裕泽]
- 关于郭永怀事迹的回顾[张长富]
- 严谨的导师,可亲的长者--忆著名的空气动力学家郭永怀先生[吴兰春]
- 严谨细致 实事求是--纪念郭永怀九十诞辰[李启廉]
- 纪念核武器环境试验技术的奠基人--郭永怀副院长诞辰九十周年[李荣林]
- 郭老精神激励着材料科学研究的不断深入[周维宣 谭云]
- 郭永怀副院长的关怀与我所有机材料研究的发展[陈晓丽]
- 忆与郭永怀副院长的一次谈话[孙德纶]
- 缅怀郭永怀院士[陈家镛]
- 记郭永怀先生二三事[屠善澄]
- Remembering Yunghuai Kuo[C.C.Lin]
- Recall with love and respect[William R.Sears]
- Y.H.Kuo:An appreciation[Frank E.Marble]
- A commemorative tribute to Professor Guo Yonghuai[T.Y.Wu]
- Y.H.Kuo:A great scientist,revered teacher and good friend[Alfred Ritter]
- 氢氧燃烧及爆轰驱动激波管[俞鸿儒]
- 颗粒材料中致密波结构研究[孙锦山 朱建士 贾祥瑞]
- 网格与高精度差分计算问题[张涵信 呙超 宗文刚]
- 植被层湍流的大涡模拟[李家春 谢正桐]
- 半浮区液桥热毛细振荡流[唐泽眉 阿燕 胡文瑞]
- 再入湍流尾迹及其对雷达散射的影响研究[牛家玉 于明]
- 超声射流中CS2分子态分辨转动弛豫研究[陈从香 刘世林 戴静华 张志萍 马兴孝]
- 37mm冲压加速器实验和计算[柳森 简和祥 白智勇 平新红 部绍清]
- 化学体系中噪声诱导的时空有序结构和随机共振[辛厚文 侯中怀 杨灵法]
- 根据守恒律计算热流和摩阻的有限元提法[童秉纲 段占元]
- 高阶精度线性耗散紧致格式的渐近稳定性[邓小刚 毛枚良]
- 离散流体力学:理论和数值方法[高智]
- 2号复合离心机自动控制系统研制[王磊 林明 冯晓军]
- 海沧大桥气动弹性特性风洞试验研究[李明水 陈忻 张大康 王卫华]
- 内爆炸载荷下圆管变形、损伤和破坏规律的研究[李永池 李大红 魏志刚 孙宇新]
- 两种凝聚炸药的静态断裂性能实验研究[罗景润 韦日演 马丽莲]
- 圆柱体侵彻薄靶极限击穿速度估算探讨[吴应白 唐平]
- 动力学修改方法在夹具设计中的应用研究[蒲怀强 唐定勇]
- Numerical simulation of non-linear stability of two-dimensional supersonic boundary layer[Shen Qing Yuan Xiangjiang]
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288 p. : il.
Resumo:
本书从混凝土的细观结构层次出发,假定混凝土是由沙浆基质、骨料以及两者黏结带组成的三项复合材料,应用弹性损伤理论建立了描述混凝土细观单元的本构关系及断裂过程分析的数值模型,并以此为基础开发了材料破坏过程分析的数值模拟软件MFPA-2D,给出了混凝土在静态载荷作用下断裂过程的模拟结果,为混凝土等准脆性材料的损伤与断裂研究提供了一个数值工具。
本书可供力学、材料科学、以及水利、交通、采矿、岩土等工程领域的教学和科研人员参考。书中介绍的数值模拟软件MFPA-2D也可供相关专业研究生辅助教学使用。
前言
第一章绪论
第二章混凝土损伤与断裂的数值模型
第三章数值模型的参数研究及其验证
第四章混凝土拉伸断裂的数值模拟
第五章混凝土剪切断裂的数值模拟
第六章数值模型的优点及其应用
Resumo:
An investigation was conducted into the deaths of more than 220 bottlenose dolphins (Tursiops truncatus) that occurred within the coastal bay ecosystem of mid-Texas between January and May 1992. The high mortality rate was unusual in that it was limited to a relatively small geographical area, occurred primarily within an inshore bay system separated from the Gulf of Mexico by barrier islands, and coincided with deaths of other taxa including birds and fish. Factors examined to determine the potential causes of the dolphin mortalities included microbial pathogens, natural biotoxins, industrial pollutants, other environmental contaminants, and direct human interactions. Emphasis was placed on nonpoint source pesticide runoff from agricultural areas, which had resulted from record rainfall that occurred during the period of increased mortality. Analytical results from sediment, water, and biota indicated that biotoxins, trace metals, and industrial chemical contamination were not likely causative factors in this mortality event. Elevated concentrations of pesticides (atrazine and aldicarb) were detected in surface water samples from bays within the region, and bay salinities were reduced to <10 ppt from December 1991 through April 1992 due to record rainfall and freshwater runoff exceeding any levels since 1939. Prolonged exposure to low salinity could have played a significant role in the unusual mortalities because low salinity exposure may cause disruption of the permeability barrier in dolphin skin. The lack of established toxicity data for marine mammals, particularly dermal absorption and bioaccumulation, precludes accurate toxicological interpretation of results beyond a simple comparison to terrestrial mammalian models. Results clearly indicated that significant periods of agricultural runoff and accompanying low salinities co-occurred with the unusual mortality event in Texas, but no definitive cause of the mortalities was determined. (PDF file contains 25 pages.)
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Referência: Bibliografia da Impressão Regia do Rio de Janeiro / Ana Maria de Almeida Camargo, Rubens Borba de Moraes, 1993. v. 1, p. 220
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The 1984 International Symposium and Workshop on the Biology of Fur Seals originated in informal talks in 1981. However, the scope and focus of the symposium remained unclear until an informal workshop was held in San Diego in June 1983. This meeting synthesised data on the foraging and pup attendance activities of six species of fur seals, and attempted to formulate a coherent framework for the adaptations associated with their maternal strategies (Gentry et al. 1986). During the workshop it was clear that comparative data on many key aspects of fur seal biology and ecology were missing. This absence of data applied not only to less well known species, for some of which considerable unpublished data existed, but also to better known species for which research in some areas had either been neglected or unreported. The value of applying the comparative method to seals, especially comparisons integrating physiology, ecology, and reproductive biology, was amply demonstrated by the results of the 1983 workshop (Gentry and Kooyman 1986). However, we were also aware that many other problems outside the area of maternal strategies could benefit from comparative data, such as recovery of populations from the effects of harvesting. Therefore, to accommodate the range of potential research, we organized this symposium to produce an up-to-date synthesis of relevant information for all species of fur seals. It was also clear that fur seal research could benefit from increased communication and collaboration among its practitioners. To foster the spread of ideas, we held oral presentations on some topics of current research and techniques and organized workshops on specific topics, in addition to providing opportunities for informal talks among participants. Thanks to generous support from the British Antarctic Survey, the National Marine Fisheries Service of the United States, and the Scientific Committee on Antarctic Research, the International Fur Seal Symposium was held at the British Antarctic Survey, Cambridge, England, 23-27 April 1984. The 36 participants are shown in Figure 1. A list of Symposium participants and authors is presented in Appendix 1 of the Proceedings. (PDF file contains 220 pages.)
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Menlicirrhus americanus in the northwestern Gulf of Mexico mature at 150-220 mm TL and 12-14 months of age, with males maturing when 10-40 mm smaller than females. Spawning occurs within a broad period from February through November with two discrete peaks which coincide with the periodicity of downcoast alongshore currents (towards Mexico) in spring and fall. This species occurs at depths of less than 5 to 27 m, being most abundant at 5 m or shallower. Young-of-the-year recruit primarily at 5-9 m or shallower and gradually expand their bathymetric range. Age determination by length frequency is feasible in M. americanus but not as simple as in species that spawn in one major period of the year. Only one or two spawned groups normally predominated at anyone time and no more than three co-occurred with few possible exceptions. Observed mean sizes were 138 mm TL at 6 months, and 192 and 272 mm at ages I and II, respectively. Typical maximum size was 296-308 mm and typical maximum age is probably 2-3 years. The largest fISh captured were 392 and 455 mm. Observed sex ratio was 1.2 females to 1 male. Weight, girth, and length-length regressions are presented.(PDF file contains 27 pages.)
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Slaughtering of eels should be done not only under animal welfare aspects but as well under consumer protection and economical aspects with respect to technical feasibility. Methods must be practicable for enterprises slaughtering quantities of several kilograms up to several tons per day. Most methods applied up to now in whole Europe were (are) not in accordance with animal welfare mainly due to lacking prescriptions and alternative methods. The great number of experiments carried out within the frame of this project demonstrates the difficulties to combine optimal welfare demands with economical and technical fesibility aspects in one method. Measurements of EEG (electroencephalogram) and ECG (electrocardiogram) have shown that the method laid down in the german legislation does not perfectly stun all eels. This method was improved by applying a „prestun“ with 220 V for 1sec., followed by a 5 min phase at 45 V to prolongue the time of unconsciousness after the stun. Inflating nitrogen gas into the stunning bath additionally causes asphyxia during the stun. By this method 93% of the eels were stunned or even killed. Applying 220 V for bigger batches of eels (~400 kg) will cause big problems with the energy supply. Therefore this method is restricted to batches of 20 - 50 kg. The method laid down in the german legislation probably can be improved. Eels were stunned successfully without water, avoiding the problems of regional differences in the conductivity of the water. Other types of current and other frequencies and a combination of both should be tested as well as alternative electrode geometries also with respect to blood spots which occasionally occurred in the muscles preferably of bigger eels (>800 g). For the time being the method laid down in the german legislation is a reasonable compromise and under animal welfare aspects represents a considerable improvement.