Caverna

Este trabalho apresenta os processos de pesquisa teórica e produção visual de forma entrelaçada, a partir da experiência em uma residência artística vivida na casa da minha bisavó onde resido. A dissertação divide-se em três capítulos: o primeiro consiste em uma construção metodológica a partir da diluição das fronteiras entre os campos da antropologia e da arte; o segundo é dedicado a tratar de algumas questões que motivaram a produção da instalação Caverna (2014) e outras suscitadas durante esse processo; e, por fim, o terceiro capítulo trata de uma mudança no modo de perceber a própria residência, estimulada pelas ideias de devir e ritornelo criadas por Deleuze e Guatarri, além de apresentar o processo de criação da instalação Escritura (2015).

Caracterização mecânica e tribológica de dois glazeadores disponíveis comercialmente e uma composição experimental

O objetivo desse estudo, in vitro, foi avaliar através de testes mecânicos e tribológicos, a aplicação de dois glazeadores disponíveis comercialmente e uma composição experimental como material de cobertura em restaurações de resina composta com relação à rugosidade superficial, à dureza e à resistência ao desgaste. Foram confeccionados 24 corpos de prova (CP) do compósito Z350XT (3M/ESPE) e divididos em 4 grupos. O grupo controle (GC) não recebeu selamento, o grupo Biscover LV (GB) recebeu aplicação do Biscover LV (Bisco), o grupo Natural Glaze (GN) recebeu aplicação do Natural Glaze (Nova DFL) e o grupo Experimental (GE) recebeu aplicação de um glazeador experimental contendo nanopartículas (1% em peso). Posteriormente, os CP foram submetidos à análise da rugosidade superficial utilizando um perfilômetro e avaliação da dureza através de um nanoindentador, que fornece também o módulo elástico do material. Em seguida, os CP foram submetidos ao teste de desgaste linear alternado, durante 15.000 ciclos, com carga de 5N, em água destilada. A profundidade máxima de desgaste foi avaliada através de um perfilômetro. A análise dos dados relativos à rugosidade superficial (m) foi realizada utilizando ANOVA/Duncan (p-valor = 0,000). As médias e desvio padrão foram: GC-0,12(0,01); GB-0,06(0,01); GN-0,13(0,02); GE-0,13(0,01). A análise da dureza (GPa) e módulo elástico (GPa) foram avaliados aplicando o teste não-paramétrico de Kruskal-Wallis. As médias e desvio padrão para dureza foram: GC-1,10(0,24); GB-0,31(0,004); GN-0,08(0,004); GE-0,12(0,008) para carga de 1,25mN; GC-1,08(0,139); GB-0,32(0,004); GN-0,08(0,003); GE-0,13(0,006) para carga de 2,5mN; GC-1,10(0,101); GB-0,33(0,003); GN-0,09(0,002); GE-0,13(0,056) para carga de 5,0mN. As médias e desvio padrão para módulo elástico foram: GC-17,71(1,666); GB-5,44(0,084); GN-3,484(0,114); GE-4,55(0,178) para carga de 1,25mN; GC-17,5(1,449); GB-5,18(0,065); GN-3,38(0,078); GE-4,55(0,12) para carga de 2,5mN; GC-17,69(1,793); GB-5,04(0,041); GN-3,63(0,066); GE-4,85(0,104) para carga de 5,0mN. A análise dos dados relativos à profundidade de desgaste (m) foi realizada utilizando ANOVA/Dunnett (p-valor = 0,000). As médias e desvio padrão foram: GC-12,51(0,89); GB-0,59(0,07); GN-1,41(0,12); GE-1,84(0,18). A partir dos resultados apresentados pode-se concluir que apenas o Biscover LV foi capaz de reduzir a rugosidade superficial da resina composta testada. Os demais, Natural Glaze e Experimental, não alteraram a rugosidade superficial e foram estatisticamente semelhantes entre si e com o grupo controle. Todos os glazeadores testados reduziram a dureza e o módulo elástico da resina composta quando comparados com o grupo controle, diferindo entre si, apresentando uma ordem crescente de dureza e módulo elástico (Natural Glaze < Experimental < Biscover < Controle). Todos os glazeadores testados foram capazes de reduzir o desgaste da resina composta, quando comparados com o grupo controle, diferindo entre si, apresentado uma ordem crescente de desgaste (Biscover < Natural Glaze < Experimental < Controle).

内蒙古半干旱温带草原土壤微生物对环境变化的响应

地处干旱半干旱区的我国北方温带草原是欧亚大陆草原生物区系的重要组成部分，对全球变化敏感。土壤微生物在联系生态系统地上和地下部分起着中枢作用，由于其周转速率快，对环境因子变化响应快速，可用来指示短期内环境因子的变化对生态系统的影响。目前关于内蒙古半干旱温带草原的研究主要集中在生态系统地上部分，对地下尤其是土壤微生物对全球变化及人为干扰的响应研究仍然缺乏。本研究选取位于内蒙古多伦县的代表性的半干旱温带草原，通过对多种环境因子变化及人为干扰下土壤微生物量、呼吸、氮可利用性及转化等参数进行测定，旨在探讨全球变化及人为干扰对土壤微生物的影响，为地上植物群落的响应及生态系统地上与地下部分的联系提供机理解释，研究结果如下： 通过研究土壤微生物生物量和呼吸生长季的动态变化，以及它们对地形、火烧、施用氮肥及其交互作用的响应，结果表明，土壤微生物参数在生长季表现出明显的季节变异。土壤微生物生物量碳(MBC)、氮(MBN)分别在坡下比坡上高出14.8%和11.5%。但是，有机碳微中生物量碳的百分比(Cmic/Corg)以及总氮中微生物量氮的百分比(Nmic/Ntot)分别在坡上比坡下高16.9%和26.2%。微生物呼吸(MR)和代谢熵(qCO2)都不受地形的影响。火烧在整个生长季分别提高MBC和MBN29.8%和14.2%，MR和qCO2 则有降低趋势，尤其是在八月份。火烧在坡上提高Cmic/Corg 和Nmic/Ntot，但是在坡下对二者没有影响。氮肥的施用在第一个生长季对所有土壤微生物指标都没有影响。 草原生态中环境因子的空间和时间变异可以影响土壤微生物以及它们对干扰的响应。通过对地形、火烧、施肥进行三年连续处理和观测土壤微生物指标发现，1)土壤微生物参数有明显的年际变异。2)在相对湿润的年份，土壤微生物量在坡下比坡上高，但是Cmic/Corg和Nmic/Ntot 在坡上高于坡下。但在干旱年份里，所有土壤微生物参数都是在坡下高于坡上，且由于地形引起的差异在干旱年份表现更强烈。MBC、MBN、MR 的变异系数在坡上高，表明土壤微生物量和活性在坡下稳定性高。说明了土壤水分含量在半干旱温带草原调节土壤微生物和其稳定性方面起着重要作用。地形对土壤可利用的氮没有影响。3)每年一次的火烧对土壤微生物量、Cmic/Corg、Nmic/Ntot 有正效应但正效应随处理时间延长和处理次数增加而降低。火烧在在第一年内不论在坡上还是坡下都降低MR，但是在干旱年份里，火烧在坡上降低MR，在坡下提高MR。火烧在第二年里在坡下提高了土壤无机氮含量，但在坡上降低了土壤无机氮含量。在第三年，不论坡上还是坡下，火烧使得土壤无机氮含量降低。4)施用氮肥提高土壤无机氮含量，但是它对土壤微生物参数产生负效应，且负效应随着处理时间延长和处理次数的增加而增强。此外，氮肥增加了MBC、MBN、MR的变异系数。 土壤微生物在生态系统碳氮循环中起着关键作用，但是关于氮素添加是否促进或抑制土壤微生物生物量和活动仍然存在争议。在我国北方温带草原的这项研究目的在于探讨土壤微生物沿着一个施氮梯度的响应。本研究设置了每年一次、连续四年的八个水平(0, 1, 2, 4, 8, 16, 32, 64 g N m-2以尿素形式施入土壤)N处理。并在第三年和第四年测定了土壤微生物生物量碳、氮、磷、微生物呼吸和代谢熵、土壤无机氮、净氮矿化和硝化。大多数测定的微生物参数都在低施氮处理下有所增加，相反在高施氮处理下降低。在取样测定的两年中，对土壤微生物生长和活动的最适施氮量大致为2 g N m-2 y-1；而施氮的阈值在16 和32 gN m-2 y-1之间，在此阈值之上，土壤pH、微生物生物量、微生物呼吸、Cmic/Corg、Nmic/Ntot 急剧降低，相反，土壤无机氮、净氮矿化和硝化急剧增加。土壤微生物对低施氮处理和高施氮处理的特异性响应(Differential Response)可能是由于微生物碳氮限制的转换、以及高施氮处理下土壤pH值降低的毒害影响而引起的。本研究中观察到的土壤微生物沿着施氮梯度的非线性响应有助于解决不同报道及不同生态系统中氮素添加对土壤微生物影响的争议。 气候变化将显著影响陆地生态系统的碳循环。以2005年4月开始的一项野外控制实验为平台，检验我国北方半干旱典型草原土壤和微生物呼吸以及微生物生物量对试验增温和增加降水的响应。在3 个实验年份内(2005-2007 年)测定了整个生长季节的土壤呼吸、微生物呼吸、微生物生物量碳和微生物生物量氮。结果表明，1)受到降水年际波动的影响，土壤和微生物呼吸以及微生物生物量均存在明显的年际变化。2)实验室内沿着一个水分梯度的培养实验揭示了微生物呼吸对温度的响应受到低土壤水分含量的限制。3)在三年时间内，试验增温引起土壤和微生物呼吸以及微生物生物量的显著降低，说明试验增温通过加剧土壤水分胁迫的间接负效应大于温度增加的直接正效应。试验增温所引起的蒸发散的增加导致土壤水分可利用性减少到某一胁迫阈值(Threshold)之下，并因此抑制了植物生长、根系和微生物活动。4)降水增加显著刺激了土壤和微生物呼吸以及其它微生物参数，而且这种正效应随着时间而增强。研究结果表明：在半干旱温带草原，土壤水分在调节土壤和微生物呼吸以及微生物生物量及其对气候变化的响应方面所起的作用比温度更为重要。比较温带草原土壤呼吸与总初级生产力的相对变化显示，相对于光合碳固定而言，增温导致更多而增雨引起较少的呼吸碳损失。这一发现说明：除非降水增加，气候变暖情形下，我国北方的干旱半干旱温带草原将可能作为一个净的碳源。

Biomimicking of natural cellular materials

The role that microstructure plays in the mechanical efficiency of natural cellular materials is examined here. The focus of this study is on elastic behaviour. Two natural materials with microstructures resistant to local bucking: plant stems and animal quills have also been examined.

Chromosome painting between human and lorisiform prosimians: Evidence for the HSA 7/16 Synteny in the primate ancestral karyotype

Multidirectional chromosome painting with probes derived from flow-sorted chromosomes of humans (Homo sapiens, HSA, 2n = 46) and galagos (Galago moholi, GMO, 2n = 38) allowed us to map evolutionarily conserved chromosomal segments among humans, galagos, a

Building flexible user interfaces for solving PDEs

FEniCS is a collection of software tools for the automated solution of differential equations by finite element methods. In this note, we describe how FEniCS can be used to solve a simple nonlinear model problem with varying levels of automation. At one extreme, FEniCS provides tools for the fully automated and adaptive solution of nonlinear partial differential equations. At the other extreme, FEniCS provides a range of tools that allow the computational scientist to experiment with novel solution algorithms. © 2010 American Institute of Physics.

A FEniCS-based programming framework for modeling turbulent flow by the Reynolds-averaged Navier-Stokes equations

Finding an appropriate turbulence model for a given flow case usually calls for extensive experimentation with both models and numerical solution methods. This work presents the design and implementation of a flexible, programmable software framework for assisting with numerical experiments in computational turbulence. The framework targets Reynolds-averaged Navier-Stokes models, discretized by finite element methods. The novel implementation makes use of Python and the FEniCS package, the combination of which leads to compact and reusable code, where model- and solver-specific code resemble closely the mathematical formulation of equations and algorithms. The presented ideas and programming techniques are also applicable to other fields that involve systems of nonlinear partial differential equations. We demonstrate the framework in two applications and investigate the impact of various linearizations on the convergence properties of nonlinear solvers for a Reynolds-averaged Navier-Stokes model. © 2011 Elsevier Ltd.

Digestion of selected foods by Yunnan snub-nosed monkey Rhinopithecus bieti (Colobinae)

Three digestion trials were conducted to quantify aspects of digestive physiology in the Yunnan snub-nosed monkey Rhinopithecus bieti, a foregut fermenter that feeds primarily on lichens. Mean retention time (MRT, the average time plastic markers spent in

Genetic relationship of Chinese ethnic populations revealed by mtDNA sequence diversity

The origin and demographic history of the ethnic populations of China have not been clearly resolved. In this study, we examined the hypervariable segment I sequences (HVSI) of the mitochondrial DNA control region in 372 individuals from nine Chinese popu

Zebu Cattle Are an Exclusive Legacy of the South Asia Neolithic

Animal domestication was a major step forward in human prehistory, contributing to the emergence of more complex societies. At the time of the Neolithic transition, zebu cattle (Bos indicus) were probably the most abundant and important domestic livestock species in Southern Asia. Although archaeological evidence points toward the domestication of zebu cattle within the Indian subcontinent, the exact geographic origins and phylogenetic history of zebu cattle remains uncertain. Here, we report evidence from 844 zebu mitochondrial DNA (mtDNA) sequences surveyed from 19 Asiatic countries comprising 8 regional groups, which identify 2 distinct mitochondrial haplogroups, termed I1 and I2. The marked increase in nucleotide diversity (P < 0.001) for both the I1 and I2 haplogroups within the northern part of the Indian subcontinent is consistent with an origin for all domestic zebu in this area. For haplogroup I1, genetic diversity was highest within the Indus Valley among the three hypothesized domestication centers (Indus Valley, Ganges, and South India). These data support the Indus Valley as the most likely center of origin for the I1 haplogroup and a primary center of zebu domestication. However, for the I2 haplogroup, a complex pattern of diversity is detected, preventing the unambiguous pinpointing of the exact place of origin for this zebu maternal lineage. Our findings are discussed with respect to the archaeological record for zebu domestication within the Indian subcontinent.