994 resultados para State Fragmentation


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When high-energy single-hadron production takes place inside an identified jet, there are important correlations between the fragmentation and phase-space cuts. For example, when one-hadron yields are measured in on-resonance B-factory data, a cut on the thrust event shape T is required to remove the large b-quark contribution. This leads to a dijet final-state restriction for the light-quark fragmentation process. Here, we complete our analysis of unpolarized fragmentation of (light) quarks and gluons to a light hadron h with energy fraction z in e+e−→dijet+h at the center-of-mass energy Q=10.58  GeV. In addition to the next-to-next-to-leading order resummation of the logarithms of 1−T, we include the next-to-leading order nonsingular

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We present Plio-Pleistocene records of sediment color, %CaCO3, foraminifer fragmentation, benthic carbon isotopes (d13C) and radiogenic isotopes (Sr, Nd, Pb) of the terrigenous component from IODP Site U1313, a reoccupation of benchmark subtropical North Atlantic Ocean DSDP Site 607. We show that (inter)glacial cycles in sediment color and %CaCO3 pre-date major northern hemisphere glaciation and are unambiguously and consistently correlated to benthic oxygen isotopes back to 3.3 million years ago (Ma) and intermittently so probably back to the Miocene/Pliocene boundary. We show these lithological cycles to be driven by enhanced glacial fluxes of terrigenous material (eolian dust), not carbonate dissolution (the classic interpretation). Our radiogenic isotope data indicate a North American source for this dust (~3.3-2.4 Ma) in keeping with the interpreted source of terrestrial plant wax-derived biomarkers deposited at Site U1313. Yet our data indicate a mid latitude provenance regardless of (inter)glacial state, a finding that is inconsistent with the biomarker-inferred importance of glaciogenic mechanisms of dust production and transport. Moreover, we find that the relation between the biomarker and lithogenic components of dust accumulation is distinctly non-linear. Both records show a jump in glacial rates of accumulation from Marine Isotope Stage, MIS, G6 (2.72 Ma) onwards but the amplitude of this signal is about 3-8 times greater for biomarkers than for dust and particularly extreme during MIS 100 (2.52 Ma). We conclude that North America shifted abruptly to a distinctly more arid glacial regime from MIS G6, but major shifts in glacial North American vegetation biomes and regional wind fields (exacerbated by the growth of a large Laurentide Ice Sheet during MIS 100) likely explain amplification of this signal in the biomarker records. Our findings are consistent with wetter-than-modern reconstructions of North American continental climate under the warm high CO2 conditions of the Early Pliocene but contrast with most model predictions for the response of the hydrological cycle to anthropogenic warming over the coming 50 years (poleward expansion of the subtropical dry zones).

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Background: Models describing nuclear fragmentation and fragmentation fission deliver important input for planning nuclear physics experiments and future radioactive ion beam facilities. These models are usually benchmarked against data from stable beam experiments. In the future, two-step fragmentation reactions with exotic nuclei as stepping stones are a promising tool for reaching the most neutron-rich nuclei, creating a need for models to describe also these reactions. Purpose: We want to extend the presently available data on fragmentation reactions towards the light exotic region on the nuclear chart. Furthermore, we want to improve the understanding of projectile fragmentation especially for unstable isotopes. Method: We have measured projectile fragments from (10,12-18C) and B10-15 isotopes colliding with a carbon target. These measurements were all performed within one experiment, which gives rise to a very consistent data set. We compare our data to model calculations. Results: One-proton removal cross sections with different final neutron numbers (1 pxn) for relativistic C-10,C-12-18 and B10-15 isotopes impinging on a carbon target. Comparing model calculations to the data, we find that the EPAX code is not able to describe the data satisfactorily. Using ABRABLA07 on the other hand, we find that the average excitation energy per abraded nucleon needs to be decreased from 27 MeV to 8.1 MeV. With that decrease ABRABLA07 describes the data surprisingly well. Conclusions: Extending the available data towards light unstable nuclei with a consistent set of new data has allowed a systematic investigation of the role of the excitation energy induced in projectile fragmentation. Most striking is the apparent mass dependence of the average excitation energy per abraded nucleon. Nevertheless, this parameter, which has been related to final-state interactions, requires further study.

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Fragmentation of wildlife habitat is a primary driver of global species decline. A major contributor to habitat fragmentation in the United States is rural residential development. Rural development in Colorado is occurring at rates far greater than the national average. Additionally, the lack of state-level planning control coupled with a lack of comprehensive, effective planning tools at the local level creates conditions that contribute to habitat fragmentation in many rural counties. Greater oversight and involvement in land use planning is needed by the state level to assist county governments. This study provides five recommendations to strengthen Colorado state land use policy in order to reduce habitat fragmentation.

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The South Caucasus is situated at the intersection of Eurasia’s major transport and energy corridors, making it an important geostrategic region. Traditional regional actors Iran, Turkey and Russia have jostled for influence and power in the region for centuries, and are now faced with competition from the EU, China, the US and NATO. Although Armenia, Azerbaijan and Georgia have been independent for more than two decades, they still continue to feel the sway, and sometimes threat, of external actors. As a response, the three South Caucasus states have chosen very different geostrategic paths since the collapse of the Soviet Union, leaving the region more fragmented and volatile than ever. In this book, various authors offer a deep and broad understanding of the developments in the South Caucasus, analyse the different foreign trajectories that each of the three state is following, and highlight the impact of external actors’ policies.

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Stationary-phase bacterial cells are characterized by vastly reduced metabolic activities yielding a dormant-like phenotype. Several hibernation programs ensure the establishment and maintenance of this resting growth state. Some of the stationary phase-specific modulations affect the ribosome and its translational activity directly. In stationary-phase Escherichia coli, we observed the appearance of a 16S rRNA fragmentation event at the tip of helix 6 within the small ribosomal subunit (30S). Stationary-phase 30S subunits showed markedly reduced activities in protein biosynthesis. On the other hand, the functional performance of stationary-phase large ribosomal subunits (50S) was indistinguishable from particles isolated from exponentially growing cells. Introduction of the 16S rRNA cut in vitro at helix 6 of exponential phase 30S subunits renders them less efficient in protein biosynthesis. This indicates that the helix 6 fragmentation is necessary and sufficient to attenuate translational activities of 30S ribosomal subunits. These results suggest that stationary phase-specific cleavage of 16S rRNA within the 30S subunit is an efficient means to reduce global translation activities under non-proliferating growth conditions.

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Mannitol is an essential excipient employed in orally disintegrating tablets due to its high palatability. However its fundamental disadvantage is its fragmentation during direct compression, producing mechanically weak tablets. The primary aim of this study was to assess the fracture behaviour of crystalline mannitol in relation to the energy input during direct compression, utilising ball milling as the method of energy input, whilst assessing tablet characteristics of post-milled powders. Results indicated that crystalline mannitol fractured at the hydrophilic (011) plane, as observed through SEM, alongside a reduction in dispersive surface energy. Disintegration times of post-milled tablets were reduced due to the exposure of the hydrophilic plane, whilst more robust tablets were produced. This was shown through higher tablet hardness and increased plastic deformation profiles of the post-milled powders, as observed with a lower yield pressure through an out-of-die Heckel analysis. Evaluation of crystal state using x-ray diffraction/differential scanning calorimetry showed that mannitol predominantly retained the β-polymorph; however x-ray diffraction provided a novel method to calculate energy input into the powders during ball milling. It can be concluded that particle size reduction is a pragmatic strategy to overcome the current limitation of mannitol fragmentation and provide improvements in tablet properties.

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During the nineties, Colombia experienced a two-fold process of restructuring. First, the political system underwent a process of constitutional reform in order to strengthen the state and increase its legitimacy, surpass the exclusionary character of the political regime, and achieve greater equity in the distribution of social resources. Second, the economy made the transition from a Keynesian development strategy to a strategy of “opening” or liberalization and internationalization of the economy, in order to increase the economic efficiency by reducing the “size” of the state and its regulatory role. The purpose of this dissertation is to analyze the interplay and contradictions of economic and political factors in the restructuring of the Colombian politico-economic system. ^ The main finding of this dissertation is that the simultaneous adoption of a neoliberal economic strategy and of the Political Constitution of 1991, have had a contradictory relationship: while the “political opening” has produced favorable conditions for fostering programs of democratization and social integration, the “economic opening” has counteracted that possibility given that it implies a social exclusionary process. This tension has aggravated the problems of political and social integration that have traditionally characterized Colombian society. ^ This crucial tension has also been characteristic of Latin America in the nineties. However, it has been neglected and undertheorized in most of the democratization studies of American comparative politics. Most of them lack consideration of structural aspects. According to those studies, the cause of regime change is determined by the strategic elections of actors. Contrary to these approaches, I develop a structural perspective. I consider that social phenomena are partly determined by structural factors, and scientific research should assign them decisive importance, since a fundamental basis for social action and transformation is to be found in the dynamics of relationships between individuals and structures and the development of contradictions within structures. ^

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This dissertation seeks to explain the role of governmental and non-governmental actors in increasing/reducing the emergence of intergroup conflict after war, when group differences have been a salient aspect of group mobilization. This question emerges from several interrelated branches of scholarship on self-enforcing institutions and power-sharing arrangements, group fragmentation and demographic change, collective mobilization for collectively-targeted violence, and conflict termination and the post-conflict quality of peace. This question is investigated through quantitative analyses performed at the sub-national, national, and cross-national level on the effect of elite competition on the likelihood of violence committed on the basis of group difference after war. These quantitative analyses are each accompanied by qualitative, case study analyses drawn from the American Reconstruction South, Iraq, and Cote d'Ivoire that illustrate and clarify the mechanisms evaluated through quantitative analysis.

Shared findings suggest the correlation of reduced political competition with the increased likelihood of violence committed on the basis of group difference. Separate findings shed light on how covariates related to control over rent extraction and armed forces, decentralization, and citizenship can lead to a reduction in violence. However, these same quantitative analyses and case study analysis suggest that the control of the state can be perceived as a threat after the end of conflict. Further, together these findings suggest the political nature of violence committed on the basis of group difference as opposed to ethnic identity or resource scarcity alone.

Together, these combined analyses shed light on how and why political identities are formed and mobilized for the purpose of committing political violence after war. In this sense, they shed light on the factors that constrain post-conflict violence in deeply divided societies, and contribute to relevant academic, policy, and normative questions.

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In its open and private-based dimension, the Internet is the epitome of the Liberal International Order in its global spatial dimension. Therefore, normative questions arise from the emergence of powerful non-liberal actors such as China in Internet governance. In particular, China has supported a UN-based multilateral Internet governance model based on state sovereignty aimed at replacing the existing ICANN-based multistakeholder model. While persistent, this debate has become less dualistic through time. However, fear of Internet fragmentation has increased as the US-China technological competition grew harsher. This thesis inquires “(To what extent) are Chinese stakeholders reshaping the rules of Global Internet Governance?”. This is further unpacked in three smaller questions: (i) (To what extent) are Chinese stakeholders contributing to increased state influence in multistakeholder fora?; (ii) (how) is China contributing to Internet fragmentation?; and (iii) what are the main drivers of Chinese stakeholders’ stances? To answer these questions, Chinese stakeholders’ actions are observed in the making and management of critical Internet resources at the IETF and ICANN respectively, and in mobile connectivity standard-making at 3GPP. Through the lens of norm entrepreneurship in regime complexes, this thesis interprets changes and persistence in the Internet governance normative order and Chinese attitudes towards it. Three research methods are employed: network analysis, semi-structured expert interviews, and thematic document analysis. While China has enhanced state intervention in several technological fields, fostering debates on digital sovereignty, this research finds that the Chinese government does not exert full control on its domestic private actors and concludes that Chinese stakeholders have increasingly adapted to multistakeholder Internet governance as they grew influential within it. To enhance control over Internet-based activities, the Chinese government resorted to regulatory and technical control domestically rather than establishing a splinternet. This is due to Chinese stakeholders’ interest in retaining the network benefits of global interconnectivity.

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Ochnaceae s.str. (Malpighiales) are a pantropical family of about 500 species and 27 genera of almost exclusively woody plants. Infrafamilial classification and relationships have been controversial partially due to the lack of a robust phylogenetic framework. Including all genera except Indosinia and Perissocarpa and DNA sequence data for five DNA regions (ITS, matK, ndhF, rbcL, trnL-F), we provide for the first time a nearly complete molecular phylogenetic analysis of Ochnaceae s.l. resolving most of the phylogenetic backbone of the family. Based on this, we present a new classification of Ochnaceae s.l., with Medusagynoideae and Quiinoideae included as subfamilies and the former subfamilies Ochnoideae and Sauvagesioideae recognized at the rank of tribe. Our data support a monophyletic Ochneae, but Sauvagesieae in the traditional circumscription is paraphyletic because Testulea emerges as sister to the rest of Ochnoideae, and the next clade shows Luxemburgia+Philacra as sister group to the remaining Ochnoideae. To avoid paraphyly, we classify Luxemburgieae and Testuleeae as new tribes. The African genus Lophira, which has switched between subfamilies (here tribes) in past classifications, emerges as sister to all other Ochneae. Thus, endosperm-free seeds and ovules with partly to completely united integuments (resulting in an apparently single integument) are characters that unite all members of that tribe. The relationships within its largest clade, Ochnineae (former Ochneae), are poorly resolved, but former Ochninae (Brackenridgea, Ochna) are polyphyletic. Within Sauvagesieae, the genus Sauvagesia in its broad circumscription is polyphyletic as Sauvagesia serrata is sister to a clade of Adenarake, Sauvagesia spp., and three other genera. Within Quiinoideae, in contrast to former phylogenetic hypotheses, Lacunaria and Touroulia form a clade that is sister to Quiina. Bayesian ancestral state reconstructions showed that zygomorphic flowers with adaptations to buzz-pollination (poricidal anthers), a syncarpous gynoecium (a near-apocarpous gynoecium evolved independently in Quiinoideae and Ochninae), numerous ovules, septicidal capsules, and winged seeds with endosperm are the ancestral condition in Ochnoideae. Although in some lineages poricidal anthers were lost secondarily, the evolution of poricidal superstructures secured the maintenance of buzz-pollination in some of these genera, indicating a strong selective pressure on keeping that specialized pollination system.

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Very high field (29)Si-NMR measurements using a fully (29)Si-enriched URu(2)Si(2) single crystal were carried out in order to microscopically investigate the hidden order (HO) state and adjacent magnetic phases in the high field limit. At the lowest measured temperature of 0.4 K, a clear anomaly reflecting a Fermi surface instability near 22 T inside the HO state is detected by the (29)Si shift, (29)K(c). Moreover, a strong enhancement of (29)K(c) develops near a critical field H(c) ≃ 35.6 T, and the ^{29}Si-NMR signal disappears suddenly at H(c), indicating the total suppression of the HO state. Nevertheless, a weak and shifted (29)Si-NMR signal reappears for fields higher than H(c) at 4.2 K, providing evidence for a magnetic structure within the magnetic phase caused by the Ising-type anisotropy of the uranium ordered moments.

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This is an ecological, analytical and retrospective study comprising the 645 municipalities in the State of São Paulo, the scope of which was to determine the relationship between socioeconomic, demographic variables and the model of care in relation to infant mortality rates in the period from 1998 to 2008. The ratio of average annual change for each indicator per stratum coverage was calculated. Infant mortality was analyzed according to the model for repeated measures over time, adjusted for the following correction variables: the city's population, proportion of Family Health Programs (PSFs) deployed, proportion of Growth Acceleration Programs (PACs) deployed, per capita GDP and SPSRI (São Paulo social responsibility index). The analysis was performed by generalized linear models, considering the gamma distribution. Multiple comparisons were performed with the likelihood ratio with chi-square approximate distribution, considering a significance level of 5%. There was a decrease in infant mortality over the years (p < 0.05), with no significant difference from 2004 to 2008 (p > 0.05). The proportion of PSFs deployed (p < 0.0001) and per capita GDP (p < 0.0001) were significant in the model. The decline of infant mortality in this period was influenced by the growth of per capita GDP and PSFs.

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The aim of this study was to assess the quality of diet among the elderly and associations with socio-demographic variables, health-related behaviors, and diseases. A population-based cross-sectional study was conducted in a representative sample of 1,509 elderly participants in a health survey in Campinas, São Paulo State, Brazil. Food quality was assessed using the Revised Diet Quality Index (DQI-R). Mean index scores were estimated and a multiple regression model was employed for the adjusted analyses. The highest diet quality scores were associated with age 80 years or older, Evangelical religion, diabetes mellitus, and physical activity, while the lowest scores were associated with home environments shared with three or more people, smoking, and consumption of soft drinks and alcoholic beverages. The findings emphasize a general need for diet quality improvements in the elderly, specifically in subgroups with unhealthy behaviors, who should be targeted with comprehensive strategies.

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A new species of Pseudopaludicola is described from human-altered areas originally covered by Semideciduous Forest in northwestern state of São Paulo, southeastern Brazil. Morphologically, the new species differs from four species belonging to the P. pusilla group by the absence of either T-shaped terminal phalanges or toe tips expanded, and from all other congeners except P. canga and P. facureae by possessing an areolate vocal sac, with dark reticulation. The higher duration (300-700 ms) of each single, pulsed note (9-36 nonconcatenated pulses) that compose the call in the new species distinguishes it from all other 14 species of Pseudopaludicola with calls already described (10-290 ms). Absence of harmonics also differ the advertisement call of the new species from the call of its sister species P. facureae, even though these two species presented unexpected low genetic distances. Although we could not identify any single morphological character distinguishing the new species from P. facureae, a PCA and DFA performed using 12 morphometric variables evidenced significant size differences between these two species.