993 resultados para Wedgwood, Josiah, 1730-1795.
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Esta pesquisa analisa Berlin Alexanderplatz (1929), de Alfred Döblin, e Fontamara (1933), de Ignazio Silone, baseada nas novas concepções sobre o Bildungsroman, ou romance de formação, estabelecidas pelos olhares atualizadores de teóricos do século XX. O Bildungsroman, modalidade narrativa surgida no século XVIII, cuja obra paradigma é Os anos de aprendizado de Wilhelm Meister, de Johann Wolfgang Von Goethe, ressalta o desenvolvimento humano, seu processo de amadurecimento e conscientização ao longo de sua trajetória existencial. Os corpora desta dissertação são romances escritos no período conflituoso do entreguerras, cujo enredo destaca a luta interior e exterior das personagens em sobreviver àquele período e a consequente tomada de consciência adquirida neste percurso. O périplo metafórico vivenciado pelos protagonistas, de Fontamara, Berardo Viola, e de Berlin Alexanderplatz, Franz Biberkopf, tem como consequência uma nova consciência política, para o primeiro protagonista, e uma nova consciência social, para o segundo. O caminho formativo dos protagonistas constitui-se de maneira diversa. O objetivo deste estudo é, portanto, analisar como se realiza o processo de formação de Berardo Viola e Franz Biberkopf, apontando identidades e diferenças entre os dois processos, e, por fim, apontando como tais romances podem atualizar o conceito de Bildungsroman na história literária
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Transparent polycrystalline Yb:YAG ceramics were fabricated by solid-state reactive sintering a mixture of commercial Al2O3, Y2O3, and Yb2O3 powders. The powders were mixed in ethanol and doped with 0.5 wt% tetraethoxysilane, dried, and pressed. Pressed samples were sintered at 1730 degrees C in vacuum. Transparent fully dense samples with grain sizes of several micrometers were obtained. The phase from 1500 degrees to 1700 degrees C was important for the grain growth, in which the grains grew quickly and a mass of pores were eliminated from the body of the sample. Annealing was an important step to remove the vacancies of oxygen and transform Yb2+ to Yb3+. The 1 at.% Yb:YAG ceramic sample was pumped by a diode laser to study the laser properties. The maximum output power of 1.02 W was obtained with a slope efficiency of 25% at 1030 nm. The size of the lasering sample was 4 mm x 4 mm x 3 mm.
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During the last century, the population of Pacific sardine (Sardinops sagax) in the California Current Ecosystem has exhibited large fluctuations in abundance and migration behavior. From approximately 1900 to 1940, the abundance of sardine reached 3.6 million metric tons and the “northern stock” migrated from offshore of California in the spring to the coastal areas near Oregon, Washington, and Vancouver Island in the summer. In the 1940s, the sardine stock collapsed and the few remaining sardine schools concentrated in the coastal region off southern California, year-round, for the next 50 years. The stock gradually recovered in the late 1980s and resumed its seasonal migration between regions off southern California and Canada. Recently, a model was developed which predicts the potential habitat for the northern stock of Pacific sardine and its seasonal dynamics. The habitat predictions were successfully validated using data from sardine surveys using the daily egg production method; scientific trawl surveys off the Columbia River mouth; and commercial sardine landings off Oregon, Washington, and Vancouver Island. Here, the predictions of the potential habitat and seasonal migration of the northern stock of sardine are validated using data from “acoustic–trawl” surveys of the entire west coast of the United States during the spring and summer of 2008. The estimates of sardine biomass and lengths from the two surveys are not significantly different between spring and summer, indicating that they are representative of the entire stock. The results also confirm that the model of potential sardine habitat can be used to optimally apply survey effort and thus minimize random and systematic sampling error in the biomass estimates. Furthermore, the acoustic–trawl survey data are useful to estimate concurrently the distributions and abundances of other pelagic fishes.
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The abundances and distributions of coastal pelagic fish species in the California Current Ecosystem from San Diego to southern Vancouver Island, were estimated from combined acoustic and trawl surveys conducted in the spring of 2006, 2008, and 2010. Pacific sardine (Sardinops sagax), jack mackerel (Trachurus symmetricus), and Pacific mackerel (Scomber japonicus) were the dominant coastal pelagic fish species, in that order. Northern anchovy (Engraulis mordax) and Pacific herring (Clupea pallasii) were sampled only sporadically and therefore estimates for these species were unreliable. The estimates of sardine biomass compared well with those of the annual assessments and confirmed a declining trajectory of the “northern stock” since 2006. During the sampling period, the biomass of jack mackerel was stable or increasing, and that of Pacific mackerel was low and variable. The uncertainties in these estimates are mostly the result of spatial patchiness which increased from sardine to mackerels to anchovy and herring. Future surveys of coastal pelagic fish species in the California Current Ecosystem should benefit from adaptive sampling based on modeled habitat; increased echosounder and trawl sampling, particularly for the most patchy and nearshore species; and directed-trawl sampling for improved species identification and estimations of their acoustic target stren
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O gênero Synbranchus, principal grupo representante da família Synbranchidae no Brasil é composto por três espécies: Synbranchus marmoratus Bloch, 1795, com distribuição do Norte da Argentina até o México; Synbranchus madeirae Rosen e Rumney, 1972, encontrado no Rio Madeira, Bacia Amazônica; e Synbranchus lampreia Favorito et al., 2005, encontrada no Rio Goiapi, Ilha de Marajó. Após a descrição de S. marmoratus (primeira espécie descrita para o gênero) outras doze espécies foram descritas para o grupo até o início do século XX. Em função da imprecisão das descrições e/ou ausência de holótipos conhecidos, Günther (1870) e Ringuelet (1967) colocaram-as em sinonímia com S. marmoratus. Incrédulos da distribuição geográfica tão ampla da espécie Norte da Argentina até o México e fundamentados na imprecisão das descrições, trabalhos posteriores verificaram a presença de outras espécies sobrepondo certos sítios de distribuição da espécie Synbranchus marmoratus. Como resultado, foram descritas as espécies Synbranchus madeirae e Synbranchus lampreia, além de uma nova espécie para o gênero Ophisternon, O. aenigmaticum Rosen e Greenwood, 1976. Ainda hoje, acredita-se que a espécie Synbranchus marmoratus seja, na realidade, formada por um complexo de espécies (ROSEN e GREENWOOD, 1976). Em função da escassez de estudos osteológicos completos e de caracteres diagnósticos bem definidos, as espécies do gênero Synbranchus são difíceis de serem distinguidas e a espécie S. marmoratus é frequentemente confundida com a espécie O. aenigmaticum. Além disso, trabalhos anteriores (FAVORITO-AMORIM, 1992, 1998) revelaram a existência de espécimes do gênero Synbranchus que não possuem algumas características diagnósticas para esse gênero. O presente estudo apresentou, pela primeira vez, a osteologia completa da espécie Synbranchus marmoratus, comparou exemplares dessa espécie oriundos de diferentes localidades e examinou alguns dos caracteres diagnósticos definidos para o gênero Synbranchus e suas espécies. Não foi possível encontrar diferenças significativas entre os espécimes provenientes de diferentes localidades, que justificasse a separação destes em espécies distintas. O resultado mostrou que alguns dos caracteres diagnósticos para o gênero Synbranchus não são exclusivos para esse grupo ou são extremamente variáveis entre os espécimes, reiterando a necessidade de uma rediagnose para esse gênero, anteriormente proposta por Favorito-Amorim (1992,1998) e Favorito et al. (2005). O resultado do exame dos caracteres diagnósticos das espécies do gênero Synbranchus apresentou um resultado semelhante, revelando que diversas características utilizadas para a distinção das espécies são, na realidade compartilhadas ou sobrepõem-se. Os resultados sugerem que a descrição completa da osteologia se S. marmoratus revelou-se uma importante ferramenta taxonômica e mostrou que faz-se necessária a realização de estudos osteológicos envolvendo as demais espécies do gênero Synbranchus.
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首先回顾了以往苏铁研究,在此基础上,对苏铁的区系地理、苏铁中种皮形态、台湾苏铁的模式产地与海南苏铁的名实问题、从叶绿体DNA matK序列及应用Trn L(UAA)序列资料分析苏铁目系统发育关系等方面进行了深入的研究。 提出了我国西南及印度支那地区和澳大利亚及太平洋岛屿为现代苏铁两大分布中心,前者是苏铁科的演化中心,而后者是次生的分化中心。首次提出钉羊齿(Rhaphidopteris)可能是现代苏铁科近祖的观点。 首次系统研究了27种苏铁属植物中种皮的形态,据此把苏铁属种子分为苏铁型、台湾苏铁型、韦德苏铁型、拳叶苏铁型、斯曼苏铁型及粉种苏铁型等6个类型。对苏铁亚属中种皮纹饰的演化趋势以及其与种间亲缘关系进行了探讨。 对台湾苏铁(Cycas taiwaniana)的模式产地进行了深入的考证,认为其来自福建厦门一带的栽培植株,而非其他学者认为的广东汕头或台湾高雄。海南苏铁(C.hainanensis)应作为台湾苏铁的异名处理。 描述了苏铁科一新亚属奥苏铁亚属Subgen. Media,二新组台湾苏铁组Sect. Taiwanianae及韦德苏铁组Sect. Wadeanae。 分子研究表明托叶铁属(Stangeria)与波温铁属(Bowenia)并不构成一个单系类群;大泽米铁属(Macroz以mia)与非洲铁属(Encephalartos)关系最近,而与鳞叶铁属(Lepidozamia)稍远。 其次,在园林规划方面,对广东省江门市白水带风景区的森林植被进行深入的研究,在此基础上开展了白水带植物景观规划与植被改造规划。在跨越林学与园林两大学科方面做了开拓性的尝试,大气势、大手笔营造森林植物景观。以小班为单位进行规划,植被改造依据植物群落演替原理,模拟南亚热带季风常绿阔叶林,将种类贫乏、结构简单的人工林逐步改造为种类丰富、结构复杂的异龄复层混交林。首次以四季不同种类的花色变化的大范围森林景观来营造南亚热带平常并不明显的季相变化;而专类园的规划注意生态与景观的结合,从植物的生态学特性、群落学特性和景观要求出发进行配置,从而克服一般北京植物园注重品种收集,按分类系统或地理分布来布置而轻视植物生态习性与景观效果的通病。对现有的海金沙(Lygodium Japonicum)等层片或单优群落加以整理形成自然且景观优美的特色层片以及以江门的乡土植物与优秀外引植物营造独木成林、万雀迎宾、层峦叠嶂、孔雀开屏、仙鹤望天等景观的规划思想为国内首创;在国内首先提出规划建设热带雨林、冷色北京植物园、佛教北京植物园、国树国花园等专类园。 在白水带规划的同时,就江门市的人居环境进行了深入的调研。对国内城市生态环境建设普遍存在的一些倾向与问题进行了反思,在总结江门城市环境建设得失的基础上提出了营造可持续发展的人居环境七个方面的战略性意见。
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组织培养能够诱导染色体断裂和重接进而产生染色体易位的观点已被广泛认识。大量的研究注意到了组织培养产生的核型不稳定性,其中大多数研究的对象是栽培作物及其属间或种间杂种幼胚和幼穗再生植株。借助于减数分裂分析、染色体分带和其它检测技术,在再生植株中发现了包括易位在内的许多染色体变异。可以相信,除了传统的同源和部分同源染色体配对时的自发易位和辐射诱变等方法以外,远缘杂种组织培养有可能作为产生染色体易位的又一种选择。尽管如此,至今还没有取得培养细胞中染色体易位的直接证据。本研究以普通小麦×硬粒小麦-簇毛麦双二倍体杂种为材料,研究了组织培养过程中离体细胞的染色体变异,用基因组原位杂交技术(GISH)证实组织培养诱导小麦染色体与簇毛麦染色体发生易位。同时,研究了小麦×黑麦杂种培养细胞中的染色体变异和黑麦B-染色体的变化。利用组织培养技术获得了小麦-黑麦和小麦-长穗偃麦草代换系和附加系。 1 普通小麦比较容易与硬粒小麦-簇毛麦双二倍体TH_1和TH_1W杂交,所选的9个普通小麦品种或品系与TH_1和TH_1W配制的19个杂交组合,平均结实率为46.7%,共计获得19个杂交组合2316粒杂种种子。正反交结果表明,以普通小麦为母本的杂交结实率高于反交结实率。在继代培养过程中,杂种幼胚愈伤组织生长迅速,甚至直接诱导出绿苗,共获得不同杂交组合2005株再生植株。 2 普通小麦与硬粒小麦-簇毛麦双二倍体杂种愈伤组织发生了比较大范围的染色体数目和结构变异。在检查的中国春×TH_1W、TH_1W×84加7911515、TH_1×84加7911515、TH_1W×91E27、鲁资357×TH_1W等5个杂种组合的1730个愈伤组织细胞中,平均有19.1%的细胞发生了染色体数目变异,不同杂交组合变化在12.7%(中国春×TH_1W)至30.7%(TH_1×84加7911515),其中,以染色体数目减少的变异为主,数目增加的变异比较少。杂种愈伤组织平均有6.3%的细胞发生了染色体断裂,产生染色体断片、环状染色体、端着丝点染色体和缺失染色体。断裂的染色体可能重新融合在一起,形成双着丝点染色体。 3 培养时间影响普通小麦×硬粒小麦-簇毛麦双二倍体和普通小麦×黑麦杂种愈伤组织细胞中的染色体数目和结构变异。在一定时间里,随着培养时间的延长,未发生核型变异的细胞逐渐减少,发生变异的细胞逐渐增多,主要表现在染色体数目减少的细胞增多,而染色体数目增加的细胞有减少的趋势。在长时间培养(190日龄)的愈伤组织中染色体加倍的细胞消失了,表明长时间培养对高倍性的细胞具有不利的选择,使这类细胞难以在长期继代培养中生存下去。愈伤组织在第一次继代培养时就发现有核型变异,说明染色体变异在愈伤组织培养初期就可以发生。 4 以簇毛麦总基因组DNA为探针,采用荧光原位杂交技术在普通小麦×硬粒小麦-簇毛麦双二倍体杂种愈伤组织细胞中发现小麦染色体与簇毛麦染色体发性易位,这一结果是组织培养诱导培养细胞中属间染色体易位的第一个直观的证据。易位的染色体既有臂间易位,也有小片段易位。易位的染色体不仅可以在愈伤组织细胞中存在,也能够在再生植株中表达。在64株中国春×TH_1W和NPFP×TH_1再生植株中,观察到了3个易位株,其中1个易位株是一个小麦染色体与一个簇毛麦染色体发生了相互易位,易位的簇毛麦染色体片段比较小,大约为簇毛麦染色体臂的1/2,而易位的小麦染色体大约是臂长的1/3,另外2个易位株染色体断点位于或靠近着丝点。本研究的结果再次证实了利用组织培养能够创造小麦与外源染色体之间发生易位。 5 ~(60)Co γ-射线辐射处理对于普通小麦中国春与硬粒小麦-簇毛麦双二倍体TH_1W杂种愈伤组织细胞的染色体变异有很大的影响。表现在未发生变异的细胞大大减少,发生染色体数目变异的细胞急剧增加,主要是染色体数目减少的变异提高了21.3%,相反染色体增加的变异不但没有增加,而且还有所减少。经过辐射处理的愈伤组织细胞染色体结构变异也有大幅度增加,变异频率提高,变异类型增加。发生染色体断裂和重接形成双着丝点染色体的细胞频率达到22.3%,比对照提高13.9%。辐射诱变对培养细胞中簇毛麦染色体变异发生明显的影响。与此同时,簇毛麦染色体与小麦染色体易位频率比对照提高了近2倍。观察结果还表明愈伤组织辐射处理比延长培养时间诱导染色体变异的效果更好。 6 尽管愈伤组织中发生的染色体变异在再生植株中多有发现,但是,只有比较小范围染色体变异的愈伤组织细胞具有再生能力形成再生植株,那些发生剧烈变异的细胞通常不具有再生能力,因而不能在再生植株中得到表达。普通小麦与硬粒小麦-簇毛麦双二倍体杂种大多数再生植株染色体数目与供体杂种保持一致,只有少数植株发生染色体数目变异。显然,发生较大染色体变异的愈伤组织细胞在增殖和分化过程中处于不利的地位,逐渐被淘汰。 7 在普通小麦与硬粒小麦-簇毛麦与黑麦杂种愈伤组织中,观察到相当高频率的染色体加倍细胞,为利用组织培养创造双二倍体提供了一种可能。但是,加倍的细胞只是培养初期的愈伤组织中出现,经过一段时间的培养,这种细胞大多消失了。而且,大多数再生植株染色体数目未发生加倍,其中并没有出现期望的双二倍体植株。表明加倍了的细胞在愈伤组织生长和分化过程中大范围变异的细胞一样受到不利的选择,再生能力比较差。因此,利用组织培养创造双二倍体需要更大的努力。 8 一些黑麦品种含有数目不等的B-染色体。B-染色体的多少对普通小麦与黑麦的杂交结实率有比较大的影响,数目越多,杂交结实率越低。在培养初期的愈伤组织细胞中,B-染色体的频率很高,例如69%的中国春×芬7416杂种的40日龄愈伤组织细胞中含有数目不等的B-染色体。常染色体的倍性影响B-染色体的分布,染色体数目加倍的双二倍体细胞中含多数B-染色体的细胞频率大大高于单倍体细胞。经过一段时间的培养之后,绝大多数B-染色体都不存在了,只有极少数细胞含有1个B-染色体。可能的原因是离体培养过程对B-染色体产生了不利的选择。 9 利用组织培养技术,从普通小麦与八倍体小黑麦杂种幼胚再生植株自交后代中选育出2个异代换系,从4D缺体小麦×八倍体小黑麦再生植株回交后代中选育出1个附加系。荧光原位杂交、C-分带和种子贮藏蛋白分析证明这两个代换系1D/1R代换,附加的也是1R染色体。从4D缺体小麦与八倍体小偃麦杂种再生植株自交和回交后代中选育出5个代换系和2个附加系。染色体配对和RAPD分析证实了长穗偃麦草染色质的存在。其中一些小麦-长穗偃麦草代换系和附加系对叶锈病免疫或高抗,对条锈病的一些生理小种和白粉病具有比较高的抗性。而且,附加系924和代换系807蛋白质含量分别达到19.32%和18.83%。 10 当普通小麦鲁资357与硬粒小麦-簇毛麦双二倍体杂交时,无论是实生苗还是再生植株都发生杂种致死现象。细胞学观察没有发现植株染色体发生变异,荧光原位杂交表明簇毛麦染色也没有发生可见的变异。推测这种杂种致死现象是由于鲁资357和硬粒小麦81086A(TH_1和TH_1W的硬粒小麦亲本)中可能分别带有互补的杂种致死基因所致。
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本文综述了草原群落土壤呼吸研究的理论、方法、最新进展和主要成果。从2001年6月5日到10月15日,在内蒙古锡林河流域的一个典型草原群落放牧地段用气相色谱法对土壤呼吸进行了测定,并同期观测相应的环境因子,分析了它们之间的相互关系,并根据根系生物量和土壤呼吸的相关性外推出根系呼吸占土壤总呼吸的比例。同时,采用碱液吸收法对该草原群落和一个沼泽化草甸群落的土壤呼吸进行了比对测定,比较在不同生境下土壤呼吸速率的差异。另外,重点比较了两种常用的土壤呼吸测量方法——碱液吸收法和气相色谱法对典型草原群落土壤呼吸的测量效果。主要研究成果如下: 1.在草原群落,生物量(包括地上和地下生物量)、温度(包括气温和土壤温度)和水分及土壤呼吸的季节变化均呈不规则的波动曲线;土壤呼吸与土壤湿度高度相关,与温度尤其是土壤温度以及地下生物量之间存在着一定的相关性,但和地上生物量及绿色生物量之间几乎没有关系。 2.草原群落和草甸群落土壤呼吸的季节动态基本一致,均出现了两个峰值,分别出现在6月底和7月底,它们的变化范围分别为312.8~1738.9 mg C﹒m-2﹒d-1 和 354.6 ~2235.6 mg C﹒m-2﹒d-1,日平均土壤呼吸速率分别为785.9 mg C﹒m-2﹒d-1 和1349.6 mg C﹒m-2﹒d-1,草甸群落的土壤呼吸速率明显高于草原群落; 3.土壤水分是草原群落土壤呼吸的主要限制因子,但对草甸群落的土壤呼吸变化却基本没有影响;草甸群落中,地上总生物量与土壤呼吸速率间没有显著的相关关系,但地上部分绿色生物量与土壤呼吸间存在着显著的幂函数关系,而在草原群落中,土壤呼吸速率与地上活生物量或地上总生物量的相关关系均很弱。 4.在草原群落,根系呼吸占土壤总呼吸的比例为60.7% - 93.3%,平均为82%; 5.碱液吸收法和气相色谱法的测定结果具有很高的相关性(R2=0.7563),它们的季节动态基本一致,变化范围分别为从249.3~1795.1 mg C﹒m-2﹒d-1和从312.8~1738.9 mg C﹒m-2﹒d-1,平均值分别为634.2 mg C﹒m-2﹒d-1和802.7 mg C﹒m-2﹒d-1,碱液吸收法的测量值是气相色谱法的约1.4倍。
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In this paper, the effects of wake/leading-edge interactions were studied at off-design conditions. Measurements were performed on the stator-blade suction surface at midspan. The leading-edge flow-field was investigated using hotwire micro-traverses, hotfilm surface shear-stress sensors and pressure micro-tappings. The trailing-edge flow-field was investigated using hotwire boundary-layer traverses. Unsteady CFD calculations were also performed to aid the interpretation of the results. At low flow coefficients, the time-averaged momentum thickness of the leading-edge boundary layer was found to rise as the flow coefficient was reduced. The time-resolved momentum-thickness rose due to the interaction of the incoming rotor wake. As the flow coefficient was reduced, the incoming wakes increased in pitch-wise extent, velocity deficit and turbulence intensity. This increased both the time-resolved rise in the momentum thickness and the turbulent spot production within the wake affected boundary-layer. Close to stall, a drop in the leading-edge momentum thickness was observed in-between wake events. This was associated with the formation of a leading-edge separation bubble in-between wake events. The wake interaction with the bubble gave rise to a shedding phenomenon, which produced large length scale disturbances in the surface shear stress. Copyright © 2008 by ASME.
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本文对3个新S-DABO类衍合物(RZK-4、RZK-5、RZK-6)的体外抗HIV活性进行了研究。化合物RZK-4、RZK-5和RZK-6在200μg·mL-1的浓度下均能完全抑制HIV-1逆转录酶的活性。3个化合物对多种细胞均呈现出低毒性,且均在较低浓度下具有抑制HIV-1病毒实验株、临床株和耐药株的作用,治疗指数为3704~38462。其中,化合物RZK-6对HIV-1耐药株HIV-1IIIBA17具有非常显著的抑制作用。结果表明,这3种S-DABO类衍生物有良好的体外抗HIV-1作用,具有开发成为抗HIV-1药物的前景。
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Charles Darwin the research ship undertook an Oceanographic Cruise in 1986, CD 86/17 of the North Arabian Sea. Sediment cores were collected between 15° and 25°N. In this study sediment cores collected from deep Indus and Oman basins (CD 1715, CD 1730, CD 1738) have been analyzed for mineralogy, water content and porosity. In general, the cores are mainly composed of clay to silt sized terrigenous and biogenic constituents. Quartz, Chlorite and Illite are the common minerals of Arabian Sea sediments. Porosity determined by water content of sediments has been correlated with quartz/chlorite and quartz/illite peak ratios to show a relationship between mineral composition and physical properties.
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Charles Darwin the research ship undertook an Oceanographic Cruise in 1986, CD 86/17 of the North Arabian Sea. Sediment cores were collected between 15° and 25°N. In this study sediment cores collected from deep Indus and Oman basins (CD 1715, CD 1730, CD 1738) have been analyzed for mineralogy, water content and porosity. In general, the cores are mainly composed of clay to silt sized terrigenous and biogenic constituents. Quartz, chlorite and illite are the common minerals of Arabian Sea sediments. Porosity determined by water content of sediments has been correlated with quartz/chlorite and quartz/illite peak ratios to show a relationship between mineral composition and physical properties.