958 resultados para Nuclear nonproliferation


Relevância:

30.00% 30.00%

Publicador:

Resumo:

Two nuclear crises recently haunted the Korean peninsula, one in 1993/4, the other in 2002/3. In each case the events-were strikingly similar: North Korea made public its ambition to acquire nuclear weapons and withdrew from the Nonproliferation Treaty. Then the situation rapidly deteriorated until the peninsular was literally on the verge of war. The dangers of North Korea's actions, often interpreted as nuclear brinkmanship, are evident. and much discussed, but not so the underlying patterns that have shaped the conflict in the first place. This article sheds light on some of them. It examines the role of the United States in the crisis, arguing that Washington's inability to see North Korea as anything but a threatening 'rogue state' seriously hinders both an adequate understanding and possible resolution of the conflict. Particularly significant is the current policy of pre-emptive strikes against rogue states, for it reinforces half a century of American nuclear threats towards North Korea. The problematic role of these threats has been largely obscured, not least because the highly technical discourse of security analysis has managed to present the strategic situation on the peninsula in a manner that attributes responsibility for the crisis solely to North Korea's actions, even if the situation is in reality far more complex and interactive.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

El presente trabajo de Grado tiene como propósito examinar la incidencia de las sancionesinternacionales en el marco del régimen de no proliferación nuclear en el caso de Irán durante el periodo 2006-2015, teniendo en cuenta factores históricos de años anteriores. Se analiza y explica cómo las sanciones internacionales pueden ser una medida persuasiva por violar ciertos artículos del Tratado de no Proliferación Nuclear. Finalmente identifica y analiza los tipos de sanciones económicas, financieras y comerciales que los Estados y el Consejo de Seguridad de las Naciones Unidas le han impuesto a Irán, así como la manera en que estas han incidido en la esfera política iraní y mundial.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Systemic acquired resistance (SAR) is a broad-spectrum resistance in plants that involves the upregulation of a battery of pathogenesis-related (PR) genes. NPR1 is a key regulator in the signal transduction pathway that leads to SAR. Mutations in NPR1 result in a failure to induce PR genes in systemic tissues and a heightened susceptibility to pathogen infection, whereas overexpression of the NPR1 protein leads to increased induction of the PR genes and enhanced disease resistance. We analyzed the subcellular localization of NPR1 to gain insight into the mechanism by which this protein regulates SAR. An NPR1–green fluorescent protein fusion protein, which functions the same as the endogenous NPR1 protein, was shown to accumulate in the nucleus in response to activators of SAR. To control the nuclear transport of NPR1, we made a fusion of NPR1 with the glucocorticoid receptor hormone binding domain. Using this steroid-inducible system, we clearly demonstrate that nuclear localization of NPR1 is essential for its activity in inducing PR genes.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Australasian marsupials include three major radiations, the insectivorous/carnivorous Dasyuromorphia, the omnivorous bandicoots (Peramelemorphia), and the largely herbivorous diprotodontians. Morphologists have generally considered the bandicoots and diprotodontians to be closely related, most prominently because they are both syndactylous (with the 2nd and 3rd pedal digits being fused). Molecular studies have been unable to confirm or reject this Syndactyla hypothesis. Here we present new mitochondrial (mt) genomes from a spiny bandicoot (Echymipera rufescens) and two dasyurids, a fat-tailed dunnart (Sminthopsis crassicaudata) and a northern quoll (Dasyurus hallucatus). By comparing trees derived from pairwise base-frequency differences between taxa with standard (absolute, uncorrected) distance trees, we infer that composition bias among mt protein-coding and RNA sequences is sufficient to mislead tree reconstruction. This can explain incongruence between trees obtained from mt and nuclear data sets. However, after excluding major sources of compositional heterogeneity, both the “reduced-bias” mt and nuclear data sets clearly favor a bandicoot plus dasyuromorphian association, as well as a grouping of kangaroos and possums (Phalangeriformes) among diprotodontians. Notably, alternatives to these groupings could only be confidently rejected by combining the mt and nuclear data. Elsewhere on the tree, Dromiciops appears to be sister to the monophyletic Australasian marsupials, whereas the placement of the marsupial mole (Notoryctes) remains problematic. More generally, we contend that it is desirable to combine mt genome and nuclear sequences for inferring vertebrate phylogeny, but as separately modeled process partitions. This strategy depends on detecting and excluding (or accounting for) major sources of nonhistorical signal, such as from compositional nonstationarity.