960 resultados para Machiavelli, Niccolo, 1469-1527


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• In a free-air CO2 enrichment study (BangorFACE) Alnus glutinosa, Betula pendula and Fagus sylvatica were planted in areas of one, two and three species mixtures (n=4). The trees were exposed to ambient or elevated CO2 (580 µmol mol-1) for four years, and aboveground growth characteristics measured. • In monoculture, the mean effect of CO2 enrichment on aboveground woody biomass was +29, +22 and +16% for A. glutinosa, F. sylvatica, and B. pendula respectively. When the same species were grown in polyculture, the response to CO2 switched to +10, +7 and 0%, for A. glutinosa, B. pendula, and F. sylvatica respectively. • In ambient atmosphere our species grown in polyculture increased aboveground woody biomass from 12.9 ± 1.4 kg m-2 to 18.9 ± 1.0 kg m-2, whereas in an elevated CO2 atmosphere aboveground woody biomass increased from 15.2 ± 0.6 kg m-2 to 20.2 ± 0.6 kg m-2. The overyielding effect of polyculture was smaller (+7%) in elevated CO2 than in an ambient atmosphere (+18%). • Our results show that the aboveground response to elevated CO2 is significantly affected by intra- and inter-specific competition, and that elevated CO2 response may be reduced in forest communities comprised of tree species with contrasting functional traits.

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The fast increase in the size and number of databases demands data mining approaches that are scalable to large amounts of data. This has led to the exploration of parallel computing technologies in order to perform data mining tasks concurrently using several processors. Parallelization seems to be a natural and cost-effective way to scale up data mining technologies. One of the most important of these data mining technologies is the classification of newly recorded data. This paper surveys advances in parallelization in the field of classification rule induction.

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Neuropeptide signalling at the plasma membrane is terminated by neuropeptide degradation by cell-surface peptidases, and by beta-arrestin-dependent receptor desensitization and endocytosis. However, receptors continue to signal from endosomes by beta-arrestin-dependent processes, and endosomal sorting mediates recycling and resensitization of plasma membrane signalling. The mechanisms that control signalling and trafficking of receptors in endosomes are poorly defined. We report a major role for endothelin-converting enzyme-1 (ECE-1) in controlling substance P (SP) and the neurokinin 1 receptor (NK(1)R) in endosomes of myenteric neurones. ECE-1 mRNA and protein were expressed by myenteric neurones of rat and mouse intestine. SP (10 nM, 10 min) induced interaction of NK(1)R and beta-arrestin at the plasma membrane, and the SP-NK(1)R-beta-arrestin signalosome complex trafficked by a dynamin-mediated mechanism to ECE-1-containing early endosomes, where ECE-1 can degrade SP. After 120 min, NK(1)R recycled from endosomes to the plasma membrane. ECE-1 inhibitors (SM-19712, PD-069185) and the vacuolar H(+)ATPase inhibitor bafilomycin A(1), which prevent endosomal SP degradation, suppressed NK(1)R recycling by >50%. Preincubation of neurones with SP (10 nM, 5 min) desensitized Ca(2+) transients to a second SP challenge after 10 min, and SP signals resensitized after 60 min. SM-19712 inhibited NK(1)R resensitization by >90%. ECE-1 inhibitors also caused sustained SP-induced activation of extracellular signal-regulated kinases, consistent with stabilization of the SP-NK(1)R-beta-arrestin signalosome. By degrading SP and destabilizing endosomal signalosomes, ECE-1 has a dual role in controlling endocytic signalling and trafficking of the NK(1)R: promoting resensitization of G protein-mediated plasma membrane signalling, and terminating beta-arrestin-mediated endosomal signalling.

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A review essay on debates in Germany about the creation of museums of German history

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At the core of this article is a discussion of how, why and with what implications, considerations of children’s needs are missing from the EU’s work-family reconciliation framework. Part I demonstrates how the EU has failed to properly identify, let alone acknowledge or promote, children’s interests in relation to work-family reconciliation. An examination of relevant legislation and case law shows how children are ‘missing’ from this policy area, which has huge implications for their day to day lives. Part II then considers the reasons behind, and consequences of, this reluctance to engage with children’s interests in reconciliation laws and shows how children’s well-being could be better incorporated into relevant policies and within the jurisprudence of the Court of Justice. This section highlights, for example, how the EU has been willing and able to promote children’s interests in other legal fields and suggests that changes in the Treaty, post Lisbon, offer a means to improve the current approach.

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Review essay on literature on the role of Germany in the Cold War

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This paper proposes a method for describing the distribution of observed temperatures on any day of the year such that the distribution and summary statistics of interest derived from the distribution vary smoothly through the year. The method removes the noise inherent in calculating summary statistics directly from the data thus easing comparisons of distributions and summary statistics between different periods. The method is demonstrated using daily effective temperatures (DET) derived from observations of temperature and wind speed at De Bilt, Holland. Distributions and summary statistics are obtained from 1985 to 2009 and compared to the period 1904–1984. A two-stage process first obtains parameters of a theoretical probability distribution, in this case the generalized extreme value (GEV) distribution, which describes the distribution of DET on any day of the year. Second, linear models describe seasonal variation in the parameters. Model predictions provide parameters of the GEV distribution, and therefore summary statistics, that vary smoothly through the year. There is evidence of an increasing mean temperature, a decrease in the variability in temperatures mainly in the winter and more positive skew, more warm days, in the summer. In the winter, the 2% point, the value below which 2% of observations are expected to fall, has risen by 1.2 °C, in the summer the 98% point has risen by 0.8 °C. Medians have risen by 1.1 and 0.9 °C in winter and summer, respectively. The method can be used to describe distributions of future climate projections and other climate variables. Further extensions to the methodology are suggested.

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On the 8 January 2005 the city of Carlisle in north-west England was severely flooded following 2 days of almost continuous rain over the nearby hills. Orographic enhancement of the rain through the seeder–feeder mechanism led to the very high rainfall totals. This paper shows the impact of running the Met Office Unified Model (UM) with a grid spacing of 4 and 1 km compared to the 12 km available at the time of the event. These forecasts, and forecasts from the Nimrod nowcasting system, were fed into the Probability Distributed Model (PDM) to predict river flow at the outlets of two catchments important for flood warning. The results show the benefit of increased resolution in the UM, the benefit of coupling the high-resolution rainfall forecasts to the PDM and the improvement in timeliness of flood warning that might have been possible. Copyright © 2008 Royal Meteorological Society

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It is becoming increasingly important to be able to verify the spatial accuracy of precipitation forecasts, especially with the advent of high-resolution numerical weather prediction (NWP) models. In this article, the fractions skill score (FSS) approach has been used to perform a scale-selective evaluation of precipitation forecasts during 2003 from the Met Office mesoscale model (12 km grid length). The investigation shows how skill varies with spatial scale, the scales over which the data assimilation (DA) adds most skill, and how the loss of that skill is dependent on both the spatial scale and the rainfall coverage being examined. Although these results come from a specific model, they demonstrate how this verification approach can provide a quantitative assessment of the spatial behaviour of new finer-resolution models and DA techniques.

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We investigated the on-line processing of unaccusative and unergative sentences in a group of eight Greek-speaking individuals diagnosed with Broca aphasia and a group of language-unimpaired subjects used as the baseline. The processing of unaccusativity refers to the reactivation of the postverbal trace by retrieving the mnemonic representation of the verb’s syntactically defined antecedent provided in the early part of the sentence. Our results demonstrate that the Broca group showed selective reactivation of the antecedent for the unaccusatives. We consider several interpretations for our data, including explanations focusing on the transitivization properties of nonactive and active voice-alternating unaccusatives, the costly procedure claimed to underlie the parsing of active nonvoice-alternating unaccusatives, and the animacy of the antecedent modulating the syntactic choices of the patients.

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The paper looks at the works of notable Islamic feminists to examine whether Islam can be reconciled with a substantive approach to gender equality. Located within contemporary feminist debates related to gender equality, it considers the Qur’anic verses related to two controversial areas of Shari’a law, namely, duty of obedience and polygamy, to explore how Islamic scriptures perceive ‘difference’ and its implications for substantive equality-based legal reforms in a Muslim society.

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The assumption that ‘states' primary goal is survival’ lies at the heart of the neorealist paradigm. A careful examination of the assumption, however, reveals that neorealists draw upon a number of distinct interpretations of the ‘survival assumption’ that are then treated as if they are the same, pointing towards conceptual problems that surround the treatment of state preferences. This article offers a specification that focuses on two questions that highlight the role and function of the survival assumption in the neorealist logic: (i) what do states have to lose if they fail to adopt self-help strategies?; and (ii) how does concern for relevant losses motivate state behaviour and affect international outcomes? Answering these questions through the exploration of governing elites' sensitivity towards regime stability and territorial integrity of the state, in turn, addresses the aforementioned conceptual problems. This specification has further implications for the debates among defensive and offensive realists, potential extensions of the neorealist logic beyond the Westphalian states, and the relationship between neorealist theory and policy analysis.

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In this paper we study the stochastic behavior of the prices and volatilities of a sample of six of the most important commodity markets and we compare these properties with those of the equity market. we observe a substantial degree of heterogeneity in the behavior of the series. Our findings show that it is inappropriate to treat different kinds of commodities as a single asset class as is frequently the case in the academic literature and in the industry. We demonstrate that commodities can be a useful diversifier of equity volatility as well as equity returns. Options pricing and hedging applications exemplify the economic impacts of the differences across commodities and between model specifications.

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Approximately 1–2% of net primary production by land plants is re-emitted to the atmosphere as isoprene and monoterpenes. These emissions play major roles in atmospheric chemistry and air pollution–climate interactions. Phenomenological models have been developed to predict their emission rates, but limited understanding of the function and regulation of these emissions has led to large uncertainties in model projections of air quality and greenhouse gas concentrations. We synthesize recent advances in diverse fields, from cell physiology to atmospheric remote sensing, and use this information to propose a simple conceptual model of volatile isoprenoid emission based on regulation of metabolism in the chloroplast. This may provide a robust foundation for scaling up emissions from the cellular to the global scale.

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Key point summary • Cerebellar ataxias are progressive debilitating diseases with no known treatment and are associated with defective motor function and, in particular, abnormalities to Purkinje cells. • Mutant mice with deficits in Ca2+ channel auxiliary α2δ-2 subunits are used as models of cerebellar ataxia. • Our data in the du2J mouse model shows an association between the ataxic phenotype exhibited by homozygous du2J/du2J mice and increased irregularity of Purkinje cell firing. • We show that both heterozygous +/du2J and homozygous du2J/du2J mice completely lack the strong presynaptic modulation of neuronal firing by cannabinoid CB1 receptors which is exhibited by litter-matched control mice. • These results show that the du2J ataxia model is associated with deficits in CB1 receptor signalling in the cerebellar cortex, putatively linked with compromised Ca2+ channel activity due to reduced α2δ-2 subunit expression. Knowledge of such deficits may help design therapeutic agents to combat ataxias. Abstract Cerebellar ataxias are a group of progressive, debilitating diseases often associated with abnormal Purkinje cell (PC) firing and/or degeneration. Many animal models of cerebellar ataxia display abnormalities in Ca2+ channel function. The ‘ducky’ du2J mouse model of ataxia and absence epilepsy represents a clean knock-out of the auxiliary Ca2+ channel subunit, α2δ-2, and has been associated with deficient Ca2+ channel function in the cerebellar cortex. Here, we investigate effects of du2J mutation on PC layer (PCL) and granule cell (GC) layer (GCL) neuronal spiking activity and, also, inhibitory neurotransmission at interneurone-Purkinje cell(IN-PC) synapses. Increased neuronal firing irregularity was seen in the PCL and, to a less marked extent, in the GCL in du2J/du2J, but not +/du2J, mice; these data suggest that the ataxic phenotype is associated with lack of precision of PC firing, that may also impinge on GC activity and requires expression of two du2J alleles to manifest fully. du2J mutation had no clear effect on spontaneous inhibitory postsynaptic current (sIPSC) frequency at IN-PC synapses, but was associated with increased sIPSC amplitudes. du2J mutation ablated cannabinoid CB1 receptor (CB1R)-mediated modulation of spontaneous neuronal spike firing and CB1Rmediated presynaptic inhibition of synaptic transmission at IN-PC synapses in both +/du2J and du2J/du2J mutants; effects that occurred in the absence of changes in CB1R expression. These results demonstrate that the du2J ataxia model is associated with deficient CB1R signalling in the cerebellar cortex, putatively linked with compromised Ca2+ channel activity and the ataxic phenotype.