53 research outputs found

    Arab-Israeli Conflict Four: A Preliminary Assessment

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    The dust on the latest Arab-Israeli war has not yet settled.The combatants and their supporters brace themselves for the oncoming political or, possibly, military--struggle. Many questions raised during the conduct of hostilities are still unanswered, and others will undoubtedly remain so for time to come. Yet, a preliminary assessment of some of the general characteristics of the last war is already possible

    Yersinia pestis Endowed with Increased Cytotoxicity Is Avirulent in a Bubonic Plague Model and Induces Rapid Protection against Pneumonic Plague

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    An important virulence strategy evolved by bacterial pathogens to overcome host defenses is the modulation of host cell death. Previous observations have indicated that Yersinia pestis, the causative agent of plague disease, exhibits restricted capacity to induce cell death in macrophages due to ineffective translocation of the type III secretion effector YopJ, as opposed to the readily translocated YopP, the YopJ homologue of the enteropathogen Yersinia enterocolitica O∶8. This led us to suggest that reduced cytotoxic potency may allow pathogen propagation within a shielded niche, leading to increased virulence. To test the relationship between cytotoxic potential and virulence, we replaced Y. pestis YopJ with YopP. The YopP-expressing Y. pestis strain exhibited high cytotoxic activity against macrophages in vitro. Following subcutaneous infection, this strain had reduced ability to colonize internal organs, was unable to induce septicemia and exhibited at least a 107-fold reduction in virulence. Yet, upon intravenous or intranasal infection, it was still as virulent as the wild-type strain. The subcutaneous administration of the cytotoxic Y. pestis strain appears to activate a rapid and potent systemic, CTL-independent, immunoprotective response, allowing the organism to overcome simultaneous coinfection with 10,000 LD50 of virulent Y. pestis. Moreover, three days after subcutaneous administration of this strain, animals were also protected against septicemic or primary pneumonic plague. Our findings indicate that an inverse relationship exists between the cytotoxic potential of Y. pestis and its virulence following subcutaneous infection. This appears to be associated with the ability of the engineered cytotoxic Y. pestis strain to induce very rapid, effective and long-lasting protection against bubonic and pneumonic plague. These observations have novel implications for the development of vaccines/therapies against Y. pestis and shed new light on the virulence strategies of Y. pestis in nature

    Completeness and Ambiguity of Schema Cover

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    Given a schema and a set of concepts, representative of entities in the domain of discourse, schema cover defines correspondences between concepts and parts of the schema. Schema cover aims at interpreting the schema in terms of concepts and thus, vastly simplifying the task of schema integration. In this work we investigate two properties of schema cover, namely completeness and ambiguity. The former measures the part of a schema that can be covered by a set of concepts and the latter examines the amount of overlap between concepts in a cover. To study the tradeoffs between completeness and ambiguity we define a cover model to which previous frameworks are special cases. We analyze the theoretical complexity of variations of the cover problem, some aim at maximizing completeness while others aim at minimizing ambiguity. We show that variants of the schema cover problem are hard problems in general and formulate an exhaustive search solution using integer linear programming. We then provide a thorough empirical analysis, using both real-world and simulated data sets, showing empirically that the integer linear programming solution scales well for large schemata. We also show that some instantiations of the general schema cover problem are more effective than others

    Scorpion Biodiversity and Interslope Divergence at “Evolution Canyon”, Lower Nahal Oren Microsite, Mt. Carmel, Israel

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    BACKGROUND: Local natural laboratories, designated by us as the "Evolution Canyon" model, are excellent tools to study regional and global ecological dynamics across life. They present abiotic and biotic contrasts locally, permitting the pursuit of observations and experiments across diverse taxa sharing sharp microecological subdivisions. Higher solar radiation received by the "African savannah-like" south-facing slopes (AS) in canyons north of the equator than by the opposite "European maquis-like" north-facing slopes (ES) is associated with higher abiotic stress. Scorpions are a suitable taxon to study interslope biodiversity differences, associated with the differences in abiotic factors (climate, drought), due to their ability to adapt to dry environments. METHODOLOGY/PRINCIPAL FINDINGS: Scorpions were studied by the turning stone method and by UV light methods. The pattern observed in scorpions was contrasted with similar patterns in several other taxa at the same place. As expected, the AS proved to be significantly more speciose regarding scorpions, paralleling the interslope patterns in taxa such as lizards and snakes, butterflies (Rhopalocera), beetles (families Tenebrionidae, Dermestidae, Chrysomelidae), and grasshoppers (Orthoptera). CONCLUSIONS/SIGNIFICANCE: Our results support an earlier conclusion stating that the homogenizing effects of migration and stochasticity are not able to eliminate the interslope intra- and interspecific differences in biodiversity despite an interslope distance of only 100 m at the "EC" valley bottom. In our opinion, the interslope microclimate selection, driven mainly by differences in insolance, could be the primary factor responsible for the observed interslope pattern

    Sepharadim/conversos and premodern Global Hispanism

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    Sepharadim participated in the Hispanic vernacular culture of the Iberian Peninsula. Even in the time of al-Andalus many spoke Hispano-Romance, and even their Hebrew literature belies a deep familiarity with and love of their native Hispano-Romance languages. However, since the early sixteenth century the vast majority of Sepharadim have never lived in the Hispanic world. Sepharadim lived not in Spanish colonies defined by Spanish conquest, but in a network of Mediterranean Jewish communities defined by diasporic values and institutions. By contrast, the conversos, those Sepharadim who converted to Catholicism, whether in Spain or later in Portugal, Italy, or the New World, lived mostly in Spanish Imperial lands, were officially Catholic, and spoke normative Castilian. Their connections, both real and imagined, with Sephardic cultural practice put them at risk of social marginalization, incarceration, even death. Some were devout Catholics whose heritage and family history doomed them to these outcomes. Not surprisingly, many Spanish and Portugese conversos sought refuge in lands outside of Spanish control where they might live openly as Jews. This exodus (1600s) from the lands formerly known as Sefarad led to a parallel Sephardic community of what conversos who re-embraced Judaism in Amsterdam and Italy by a generation of conversos trained in Spanish universities. The Sephardic/Converso cultural complex exceeds the boundaries of Spanish imperial geography, confuses Spanish, Portuguese, Catholic, and Jewish subjectivities, and defies traditional categories practiced in Hispanic studies, and are a unique example of the Global Hispanophone

    The Eşkenci Project : an Ottoman attempt at gradual reform (1862)

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    Donated by Klaus KreiserReprinted from in : Abr- Nahrain, 14, 1974

    The contribution of Zaporozhian Cossacks to Ottoman military reform: documents and notes

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    Donated by Klaus KreiserReprinted from in : Harvard Ukrainian Studies, Vol: 6, No: 3, 1982

    Ottoman attitudes to the rise of Balkan nationalism

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    Donated by Klaus KreiserReprinted from in : War and Society in East Central Europe, Vol: 1, 1979

    The Ottoman Ulama and the military reforms of Sultan Mahmud II

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    Donated by Klaus KreiserReprinted from in : Asian and African Studies, VII, Jerusalem, 1971
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