898 resultados para National Academy of Foreign Affairs


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Under certain special conditions natural selection can be effective at the level of local populations, or demes. Such interpopulation selection will favor genotypes that reduce the probability of extinction of their parent population even at the cost of a lowered inclusive fitness. Such genotypes may be characterized by altruistic traits only in a viscous population, i.e., in a population in which neighbors tend to be closely related. In a non-viscous population the interpopulation selection will instead favor spiteful traits when the populations are susceptible to extinction through the overutilization of the habitat, and cooperative traits when it is the newly established populations that are in the greatest danger of extinction.

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The Russian mathematician, academician and former dissident Igor Shafarevich (b. 1923) is commonly mentioned in Western scholarly studies on perestroika and post-perestroika-era Russian politics as one of the most notable anti-Semites and extreme nationalists of the country. This notoriety owes to Shafarevich’s old samizdat article Russophobia, which was published in 1988. The scandal surrounding Russophobia came to a head when the president of The National Academy of Sciences in the United States asked Shafarevich, its honorary member, to resign. Nothing like this had ever happened in the academy’s history. The present dissertation discusses Shafarevich’s political activities, his texts and ideas as well as their reception. Particular attention is given to Russophobia, whose detailed examination proves very clearly that its reputation as an anti-Semitic text is groundless. The reasons for Russophobia’s hasty but fierce condemnation were many, but only one was that when the Soviet system began to tumble, it was commonly assumed that a vigorous rise in anti-Semitism and extreme nationalism in the Soviet Union/Russia would be just a matter of time. Many observers were highly sensitised to detecting its signs and symptoms. The dissertation also shows that most of those to write the first criticisms of Russophobia and to liken Shafarevich to the ideologues of Nazi Germany were the same people he had criticised in Russophobia for their deterministic view of history and irrational manner of connecting things for the purpose of fanning the flames of distrust between Russia’s Jews and Russians. In retrospect, it is fairly evident that Shafarevich actually managed to effectively “neutralise” the message of many of those obsessed with the Jews among his Russian contemporaries and contributed to the fact that anti-Jewish sentiments have been a great deal less popular in post-communist Russia than so many had feared and expected. The thesis also thoroughly discusses Shafarevich’s other texts and activities before Russophobia’s appearance and after it. In the 1970s, Shafarevich was one of the best-known dissidents in the Soviet Union. He worked together with academician Andrei Sakharov in a dissidents’ unofficial human rights committee and co-operated closely with Aleksandr Solzhenitsyn before Solzhenitsyn’s exile. Then, during the chaotic years of perestroika, Shafarevich defended the basic rights of ordinary citizens and warned that the hype concerning democracy could become counterproductive if the most palpable result of the reforms was the disappearance of citizens’ basic security and elementary social justice. One of the conclusions of the thesis is that even if the world around Shafarevich has changed considerably, his views have remained essentially the same since the late 1960s and early 1970s.

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This is a report produced as a result of a study commissioned by the Australian Government Royal Commission into Institutional Responses to Child Sexual Abuse.

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A case study of Brisbane, the capital city of Queensland, Australia, explored how explicit measures of transit quality of service (e.g., service frequency, service span, and travel time ratio) and implicit environmental predictors (e.g., topographic grade factor) influenced bus ridership. The primary hypothesis tested was that bus ridership was higher in suburbs with high transit quality of service than in suburbs with limited service quality. Multiple linear regression, used to identify a strong positive relationship between route intensity (bus-km/h-km2) and bus ridership, indicated that both increased service frequency and spatial route density corresponded to higher bus ridership. Additionally, the travel time ratio (i.e., the ratio of in-vehicle transit travel time to in-vehicle automobile travel time) had a significant negative association with suburban ridership: transit use declined as travel time ratio increased. In contrast, topographic grade and service span did not significantly affect suburban bus ridership. The study findings enhance the fundamental understanding of traveler behavior, which is informative to urban transportation policy, planning, and provision.

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There are many studies in the literature that deal with the welfare effects of income transfers between nations in a general equilibrium setting. An important impetus for this extensive literature was the demonstration of the transfer paradox; that the donor country could actually gain from a transfer of income to another, and that the recipient could lose as a result of the gift. The reason for this paradoxical result is that the transfer gives rise to a terms-of-trade effect that may be especially beneficial to the donor and detrimental to the recipient. Subsequently, many papers have established conditions under which this paradox will or will not occur. Early work by Samuelson (1954) was followed by demonstrations of paradoxes by Gale (1974), Ohyama (1974), Brecher and Bhagwati (1982) and Bhagwati, Brecher and Hatta 1983, 1985, and Dixit (1983)) among others.1 More recently, many studies have examined whether or not foreign aid — tied and untied — can be welfare improving for both the donor and the recipient (see, for example, Turunen-Red and Woodland (1988), Kemp and Wong (1993), Schweinberger (1990), Hatzipanayotou and Michael (1995), Lahiri and Raimondos-Moller 1995, 1997, Djajić, Lahiri and Raimondos-Møller 1996a, 1996b, and Lahiri, Raimondos-Møller, Wong and Woodland 1997.2

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We develop a political–economic model of aid fungibility: a part of aid is diverted away from its intended target by lobby groups. The size of this diversion – the degree of aid fungibility – is determined endogenously by the recipient government. The donor can affect the equilibrium degree of fungibility by choosing both the size of aid and the timing of its decision. We derive a condition under which the donor's reaction to fungibility is to reduce the amount of aid. Under this condition, if the donor acts as a follower, both the donor and the target group are better off.

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The paper presents a model where the median voter in the donor country determines the support of foreign aid. It is first established that an individual in the donor country is affected by the direct benefits (due to altruism) and costs (due to taxes) of giving aid, and by the indirect benefits or costs of a change in the terms of trade. Then it is shown that the latter effect works through changing both the donor country's average income and its distribution of income. Given the stylized facts of a capital-abundant donor country and relatively capital-poor median voter, it is shown how redistribution-of-income effects soften the impact of terms-of-trade changes on the political support for foreign aid.

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We present a generic theory for the dynamics of a stiff filament under tension, in an active medium with orientational correlations, such as a microtubule in contractile actin. In sharp contrast to the case of a passive medium, we find the filament can stiffen, and possibly oscillate or buckle, depending on both the contractile or tensile nature of the activity and the filament-medium anchoring interaction. We also demonstrate a strong violation of the fluctuation-dissipation (FD) relation in the effective dynamics of the filament, including a negative FD ratio. Our approach is also of relevance to the dynamics of axons, and our model equations bear a remarkable formal similarity to those in recent work [Martin P, Hudspeth AJ, Juelicher F (2001) Proc Natl Acad Sci USA 98: 14380-14385] on auditory hair cells. Detailed tests of our predictions can be made by using a single filament in actomyosin extracts or bacterial suspensions.

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In the presence of ATP, recA protein forms a presynaptic complex with single-stranded DNA that is an obligatory intermediate in homologous pairing. Presynaptic complexes of recA protein and circular single strands that are active in forming joint molecules can be isolated by gel filtration. These isolated active complexes are nucleoprotein filaments with the following characteristics: (i) a contour length that is at least 1.5 times that of the corresponding duplex DNA molecule, (ii) an ordered structure visualized by negative staining as a striated filament with a repeat distance of 9.0 nm and a width of 9.3 nm, (iii) approximately 8 molecules of recA protein and 20 nucleotide residues per striation. The widened spacing between bases in the nucleoprotein filament means that the initial matching of complementary sequences must involve intertwining of the filament and duplex DNA, unwinding of the latter, or some combination of both to equalize the spacing between nascent base pairs. These experiments support the concept that recA protein first forms a filament with single-stranded DNA, which in turn binds to duplex DNA to mediate both homologous pairing and subsequent strand exchange.

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Gene expression noise results in protein number distributions ranging from long-tailed to Gaussian. We show how long-tailed distributions arise from a stochastic model of the constituent chemical reactions and suggest that, in conjunction with cooperative switches, they lead to more sensitive selection of a subpopulation of cells with high protein number than is possible with Gaussian distributions. Single-cell-tracking experiments are presented to validate some of the assumptions of the stochastic simulations. We also examine the effect of DNA looping on the shape of protein distributions. We further show that when switches are incorporated in the regulation of a gene via a feedback loop, the distributions can become bimodal. This might explain the bimodal distribution of certain morphogens during early embryogenesis.

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The x-ray crystal structure of the tetrameric T-antigen-binding lectin from peanut, M(r) 110,000, has been determined by using the multiple isomorphous replacement method and refined to an R value of 0.218 for 22,155 reflections within the 10- to 2.95-A resolution range. Each subunit has essentially the same characteristic tertiary fold that is found in other legume lectins. The structure, however, exhibits an unusual quaternary arrangement of subunits. Unlike other well-characterized tetrameric proteins with identical subunits, peanut lectin has neither 222 (D2) nor fourfold (C4) symmetry. A noncrystallographic twofold axis relates two halves of the molecule. The two monomers in each half are related by a local twofold axis. The mutual disposition of the axes is such that they do not lead to a closed point group. Furthermore, the structure of peanut lectin demonstrates that differences in subunit arrangement in legume lectins could be due to factors intrinsic to the protein molecule and, contrary to earlier suggestions, are not necessarily caused by interactions involving covalently linked sugar. The structure provides a useful framework for exploring the structural basis and the functional implications of the variability in the subunit arrangement in legume lectins despite all of them having nearly the same subunit structure, and also for investigating the general problem of "open" quaternary assembly in oligomeric proteins.

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Sepsis is the leading cause of death in intensive care units and results from a deleterious systemic host response to infection. Although initially perceived as potentially deleterious, catalytic antibodies have been proposed to participate in removal of metabolic wastes and protection against infection. Here we show that the presence in plasma of IgG endowed with serine protease-like hydrolytic activity strongly correlates with survival from sepsis. Variances of catalytic rates of IgG were greater in the case of patients with severe sepsis than healthy donors (P < 0.001), indicating that sepsis is associated with alterations in plasma levels of hydrolytic IgG. The catalytic rates of IgG from patients who survived were significantly greater than those of IgG from deceased patients (P < 0.05). The cumulative rate of survival was higher among patients exhibiting high rates of IgG-mediated hydrolysis as compared with patients with low hydrolytic rates (P < 0.05). An inverse correlation was also observed between the markers of severity of disseminated intravascular coagulation and rates of hydrolysis of patients' IgG. Furthermore, IgG from three surviving patients hydrolyzed factor VIII, one of which also hydrolyzed factor IX, suggesting that, in some patients, catalytic IgG may participate in the control of disseminated microvascular thrombosis. Our observations provide the first evidence that hydrolytic antibodies might play a role in recovery from a disease.

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An increase in atmospheric carbon dioxide (CO2) concentration influences climate both directly through its radiative effect (i.e., trapping longwave radiation) and indirectly through its physiological effect (i.e., reducing transpiration of land plants). Here we compare the climate response to radiative and physiological effects of increased CO2 using the National Center for Atmospheric Research (NCAR) coupled Community Land and Community Atmosphere Model. In response to a doubling of CO2, the radiative effect of CO2 causes mean surface air temperature over land to increase by 2.86 ± 0.02 K (± 1 standard error), whereas the physiological effects of CO2 on land plants alone causes air temperature over land to increase by 0.42 ± 0.02 K. Combined, these two effects cause a land surface warming of 3.33 ± 0.03 K. The radiative effect of doubling CO2 increases global runoff by 5.2 ± 0.6%, primarily by increasing precipitation over the continents. The physiological effect increases runoff by 8.4 ± 0.6%, primarily by diminishing evapotranspiration from the continents. Combined, these two effects cause a 14.9 ± 0.7% increase in runoff. Relative humidity remains roughly constant in response to CO2-radiative forcing, whereas relative humidity over land decreases in response to CO2-physiological forcing as a result of reduced plant transpiration. Our study points to an emerging consensus that the physiological effects of increasing atmospheric CO2 on land plants will increase global warming beyond that caused by the radiative effects of CO2.

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Yhteenveto: Vesistömalleihin perustuva vesistöjen seuranta- ja ennustejärjestelmä vesi- ja ympäristöhallinnossa

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Thermotropic liquid crystals are known to display rich phase behavior on temperature variation. Although the nematic phase is orientationally ordered but translationally disordered, a smectic phase is characterized by the appearance of a partial translational order in addition to a further increase in orientational order. In an attempt to understand the interplay between orientational and translational order in the mesophases that thermotropic liquid crystals typically exhibit upon cooling from the high-temperature isotropic phase, we investigate the potential energy landscapes of a family of model liquid crystalline systems. The configurations of the system corresponding to the local potential energy minima, known as the inherent structures, are determined from computer simulations across the mesophases. We find that the depth of the potential energy minima explored by the system along an isochor grows through the nematic phase as temperature drops in contrast to its insensitivity to temperature in the isotropic and smectic phases. The onset of the growth of the orientational order in the parent phase is found to induce a translational order, resulting in a smectic-like layer in the underlying inherent structures; the inherent structures, surprisingly, never seem to sustain orientational order alone if the parent nematic phase is sandwiched between the high-temperature isotropic phase and the low-temperature smectic phase. The Arrhenius temperature dependence of the orientational relaxation time breaks down near the isotropic-nematic transition. We find that this breakdown occurs at a temperature below which the system explores increasingly deeper potential energy minima.