The Library of Babel: On the origin of gravitational thermodynamics

We show that heavy pure states of gravity can appear to be mixed states to almost all probes. For AdS_5 Schwarzschild black holes, our arguments are made using the field theory dual to string theory in such spacetimes. Our results follow from applying information theoretic notions to field theory operators capable of describing very heavy states in gravity. For half-BPS states of the theory which are incipient black holes, our account is exact: typical microstates are described in gravity by a spacetime ``foam'', the precise details of which are almost invisible to almost all probes. We show that universal low-energy effective description of a foam of given global charges is via certain singular spacetime geometries. When one of the specified charges is the number of D-branes, the effective singular geometry is the half-BPS ``superstar''. We propose this as the general mechanism by which the effective thermodynamic character of gravity emerges.Comment: LaTeX, 6 eps figures, uses young.sty and wick.sty; Version 2: typos corrected, minor rewordings and clarifications, references adde

Power and Resistance: A Case Study of Satire on the Internet

Past studies on print and TV satire have revealed that satire can be seen as a site of resistance to power. In light of this, interesting questions can be raised regarding Internet satire: what does the Internet contribute to the resistance and what kind of power relation is played out on this site? Using an example from China, this paper reveals that like its print and TV counterparts, Internet satire reflects a widespread feeling of powerlessness, rather than offering the general public any political power. However, the Internet helps to push the symbolic power of satire to a higher level. This is because it makes satire a tool for the grassroots which facilitates the creation and spread of satirical ideas, and also helps to release and stimulate the enormous reserve of public wit and wisdom. As a result, satire on the Internet has the potential to generate a chain of related satirical work, which can create a satire movement and subject power to sustained shame and ridicule

Avaliação de espermatozoides caprinos congelados em meio à base de água de coco em pó (ACP-101®) ou TRIS

Compararam-se as características cinéticas e morfológicas de espermatozoides caprinos congelados nos meios à base de ACP-101® e TRIS. Os diluentes utilizados foram: ACP-101® (+ 2,5% gema ovo + 7% glicerol) e TRIS (+ 20% gema ovo + 6,8% glicerol). Quarenta e oito ejaculados de quatro bodes foram coletados, avaliados, divididos em duas alíquotas e diluídos nos meios ACP-101® e TRIS, respectivamente, posteriormente congelados e, após 30 dias, descongelados. A avaliação da motilidade espermática por computador foi realizada aos 5, 60 e 120 minutos pós-descongelação. As características de motilidade espermática analisadas foram: motilidade total (MT) (%) e progressiva (MP) (%), velocidades média do trajeto do espermatozoide (VAP) (µm/s) e linear (VSL) (µm/s) e população de espermatozoides rápidos (ER) (%). As avaliações de morfologia espermática quantificaram a porcentagem de espermatozoides normais (N) e as alterações da cabeça (AC), da peça intermediária (API) e do flagelo (AF), aos cinco e 120 minutos pós-descongelação. O diluente TRIS apresentou resultados cinéticos mais elevados que o ACP-101® aos 60 e 120 minutos pós-descongelação. As AC aos 120 minutos pós-descongelação foram mais altas nos espermatozoides congelados em ACP-101®. Conclui-se que o diluente TRIS promoveu maior viabilidade in vitro dos espermatozoides caprinos pós-descongelação

Uso de dimetil-formamida associada ou não ao glicerol na criopreservação de sêmen caprino Use of dimethylformamide associated or not with glycerol for goat semen cryopreservation

O objetivo neste trabalho foi avaliar os efeitos da dimetil-formamida na criopreservação de sêmen caprino, por meio de testes in vitro. As partidas de sêmen foram congeladas com os diluidores leite desnatado-gema, associado a diferentes crioprotetores e concentrações: 7% de glicerol (T1); 3,5% de glicerol e 3,5% de dimetil-formamida (T2) e 5% de dimetil-formamida (T3). O sêmen foi centrifugado e envasado em palhetas de 0,5 mL, sendo resfriado por 40 minutos, atingindo 5,0°C e permanecendo nesta temperatura por mais 1 hora e 20 minutos. Os parâmetros avaliados in vitro foram a motilidade progressiva e o vigor espermático, a integridade acrossômica, a integridade da membrana plasmática (HO) e a reação acrossômica. Observou-se perda de 30,0% da motilidade inicial quando as amostras foram submetidas aos procedimentos de criopreservação. A perda de integridade da membrana plasmática, avaliada pelo teste hiposmótico (HO) foi de 19%. As lesões de acrossoma aumentaram em 3% durante o teste de termo-resistência (TTR) lento. Não houve diferença entre os tratamentos quanto aos aspectos de motilidade nos tempos de 0,00; 0,05; e 1,00 horas do TTR e vigor em todos os tempos. No tempo de 2,00 horas do TTR, registrou-se diferença entre os tratamentos 1 e 2, de modo que a motilidade no tratamento 2 foi superior às demais. Os valores de integridade de membrana plasmática, integridade acrossômica e reação acrossômica pós-descongelamento não diferiram entre os tratamentos, indicando que a dimetil-formamida não foi superior ao glicerol na manutenção da qualidade espermática após a criopreservação.<br>The objective of this trial was to evaluate the efficiency of dimethylformamide on cryopreservation of goat semen using semen physical analyses and complementary tests. Alpine and Saanen bucks from the Dairy Goat Experimental Station- DZO were used. Semen samples were frozen with a yolk-skimmed milk diluent and cryoprotectors with different concentrations as follows: 7% glycerol (T1), 3.5% glycerol plus 3.5% dimethylformamide (T2) or 5% dimethylformamide (T3). Semen was centrifuged, diluted, and bottled in 0.5 mL straws followed by cooling for 40 minutes until reach 5.0°C and kept at this temperature for additional 80 minutes. Samples were then exposed to liquid nitrogen vapor for 15 minutes and finally frozen. Thawing was done in a waterbath at 37°C for 50 seconds. The following variables were evaluated in vitro: sperm progressive motility and vigor, acrosomal integrity and reaction, and plasmatic membrane integrity. The cryopreservation procedures reduced 30.0% of the initial motility and 19% of plasmatic membrane integrity that was evaluated using the hyposmotic swelling test (HOST). It was observed an increaseof 3% in acrosomal lesions when samples were submitted to a slow thermoresistance test (TRT). No significant differences in sperm motility were observed among treatments at 0, 5, and 60 minutes of TRT as well as in sperm vigor at all TRT times. However, at 120 minutes of TRT a significant difference in sperm motility was found comparing T1 and T2 while T3 was intermediate. There were no significant differences on plasmatic membrane integrity, acrosomal integrity, and post-thawing acrossomal reaction across treatments. It can be concluded that dimethylformamide can be a viable alternative for goat semen cryopreservation used alone or in association with glycerol