61 resultados para stars: kinematics and dynamics
Resumo:
BACKGROUND:Accurate quantification of the prevalence of human immunodeficiency virus type 1 (HIV-1) drug resistance in patients who are receiving antiretroviral therapy (ART) is difficult, and results from previous studies vary. We attempted to assess the prevalence and dynamics of resistance in a highly representative patient cohort from Switzerland. METHODS:On the basis of genotypic resistance test results and clinical data, we grouped patients according to their risk of harboring resistant viruses. Estimates of resistance prevalence were calculated on the basis of either the proportion of individuals with a virologic failure or confirmed drug resistance (lower estimate) or the frequency-weighted average of risk group-specific probabilities for the presence of drug resistance mutations (upper estimate). RESULTS:Lower and upper estimates of drug resistance prevalence in 8064 ART-exposed patients were 50% and 57% in 1999 and 37% and 45% in 2007, respectively. This decrease was driven by 2 mechanisms: loss to follow-up or death of high-risk patients exposed to mono- or dual-nucleoside reverse-transcriptase inhibitor therapy (lower estimates range from 72% to 75%) and continued enrollment of low-risk patients who were taking combination ART containing boosted protease inhibitors or nonnucleoside reverse-transcriptase inhibitors as first-line therapy (lower estimates range from 7% to 12%). A subset of 4184 participants (52%) had >or= 1 study visit per year during 2002-2007. In this subset, lower and upper estimates increased from 45% to 49% and from 52% to 55%, respectively. Yearly increases in prevalence were becoming smaller in later years. CONCLUSIONS:Contrary to earlier predictions, in situations of free access to drugs, close monitoring, and rapid introduction of new potent therapies, the emergence of drug-resistant viruses can be minimized at the population level. Moreover, this study demonstrates the necessity of interpreting time trends in the context of evolving cohort populations.
Resumo:
The status and dynamics of glaciers are crucial for agriculture in semiarid parts of Central Asia, since river flow is characterized by major runoff in spring and summer, supplied by glacier- and snowmelt. Ideally, this coincides with the critical period of water demand for irrigation. The present study shows a clear trend in glacier retreat between 1963 and 2000 in the Sokoluk watershed, a catchment of the Northern Tien Shan mountain range in Kyrgyzstan. The overall area loss of 28% observed for the period 1963–2000, and a clear acceleration of wastage since the 1980s, correlate with the results of previous studies in other regions of the Tien Shan as well as the Alps. In particular, glaciers smaller than 0.5 km2 have exhibited this phenomenon most starkly. While they registered a medium decrease of only 9.1% for 1963–1986, they lost 41.5% of their surface area between 1986 and 2000. Furthermore, a general increase in the minimum glacier elevation of 78 m has been observed over the last three decades. This corresponds to about one-third of the entire retreat of the minimum glacier elevation in the Northern Tien Shan since the Little Ice Age maximum.
Resumo:
The IDE used in most Smalltalk dialects such as Pharo, Squeak or Cincom Smalltalk did not evolve significantly over the last years, if not to say decades. For other languages, for instance Java, the available IDEs made tremendous progress as Eclipse or NetBeans illustrate. While the Smalltalk IDE served as an exemplar for many years, other IDEs caught up or even overtook the erstwhile leader in terms of feature-richness, usability, or code navigation facilities. In this paper we first analyze the difficulty of software navigation in the Smalltalk IDE and second illustrate with concrete examples the features we added to the Smalltalk IDE to fill the gap to modern IDEs and to provide novel, improved means to navigate source space. We show that thanks to the agility and dynamics of Smalltalk, we are able to extend and enhance with reasonable effort the Smalltalk IDE to better support software navigation, program comprehension, and software maintenance in general. One such support is the integration of dynamic information into the static source views we are familiar with. Other means include easing the access to static information (for instance by better arranging important packages) or helping developers re-locating artifacts of interest (for example with a categorization system such as smart groups).
Resumo:
Studien zu Sozialisationswirkungen sportlicher Aktivitäten auf Facetten der Persönlichkeit (z. B. Selbstkonzept) haben sich bislang in der Regel auf die Analyse isolierter Effekte des Sports konzentriert, ohne weitere Entwicklungskontexte (wie z. B. die Familie) angemessen zu berücksichtigen. Da hierin eine wesentliche Ursache für die unbefriedigende Befundlage gesehen wird, bemüht sich der Beitrag darum, die Rolle des Sports für das Selbstkonzept im komplexen Wirkungsgeflecht verschiedener Entwicklungskontexte herauszuarbeiten. 121 Heranwachsende wurden in einer personorientierten Längsschnittsstudie untersucht und die Daten mit der LICUR-Methode (z. B. Bergman, Magnusson & El-Khouri, 2003) ausgewertet. Die dabei identifizierten Subgruppen unterscheiden sich in allen untersuchten Facetten des Selbstkonzepts bedeutsam, zeigen sowohl zeitstabile als auch dynamische Werteprofile ihrer Entwicklungsfaktoren und folgen überzufällig häufig einzelnen Entwicklungswegen. Aus diesen Befunden werden Konsequenzen für eine ganzheitliche und funktionale Selbstkonzeptförderung durch Sport abgeleitet.
Resumo:
Climate affects the timing, rate and dynamics of tree growth, over time scales ranging from seconds to centuries. Monitoring how a tree's stem radius varies over these time scales can provide insight into intra-annual stem dynamics and improve our understanding of climate impacts on tree physiology and growth processes. Here, we quantify the response of radial conifer stem size to environmental fluctuations via a novel assessment of tree circadian cycles. We analyze four years of sub-hourly data collected from 56 larch and spruce trees growing along a natural temperature gradient of ∼6 °C in the central Swiss Alps. During the growing season, tree stem diameters were greatest at mid-morning and smallest in the late evening, reflecting the daily cycle of water uptake and loss. Along the gradient, amplitudes calculated from the stem radius cycle were ∼50% smaller at the upper site (∼2200 m a.s.l.) relative to the lower site (∼800 m a.s.l.). We show changes in precipitation, temperature and cloud cover have a substantial effect on typical growing season diurnal cycles; amplitudes were nine times smaller on rainy days (>10 mm), and daily amplitudes are approximately 40% larger when the mean daily temperature is 15–20 °C than when it is 5–10 °C. We find that over the growing season in the sub-alpine forests, spruce show greater daily stem water movement than larch. However, under projected future warming, larch could experience up to 50% greater stem water use, which may severely affect future growth on already dry sites. Our data further indicate that because of the confounding influences of radial growth and short-term water dynamics on stem size, conventional methodology probably overstates the effect of water-linked meteorological variables (i.e. precipitation and relative humidity) on intra-annual tree growth. We suggest future studies use intra-seasonal measurements of cell development and consider whether climatic factors produce reversible changes in stem diameter. These study design elements may help researchers more accurately quantify and attribute changes in forest productivity in response to future warming.
Resumo:
This dissertation presents the concept of Deliberative Transformative Moment and the instrument to identify it, in a further attempt to bridge the gap between deliberation theory and practice. A transformative moment in the deliberative process occurs when the level of deliberation is either lifted from low to high or drops from high to low. In order to identify such a moment, one has to look at the context and dynamics of the group discussion. This broadening of the unit of analysis is a big difference from other existing instruments to measure the level of deliberation, such as the Deliberative Quality Index –DQI, which focuses primarily on the individual speech acts. Consistent with the theoretical framework of consociational and deliberation approaches, the observed discussions took place among two deeply divided groups, Colombian ex-combatants from both the extreme left and the extreme right. Moving beyond a pure Habermasian perspective, this study finds that besides pure rational arguments, there are some contexts in which personal stories, jokes and self-interests, acting as justification of arguments, have either a positive or a negative impact on deliberative transformative moments. Although this research has a strongly qualitative orientation, reliability tests scored high, giving it strength as a reliable and valid research method that shedding some light on the sort of speech acts that enhance deliberation and those that detract from it.
Resumo:
Social interaction is a core aspect of human life that affects individuals’ physical and mental health. Social interaction usually leads to mutual engagement in diverse areas of mental, emotional, physiological and physical activity involving both interacting persons and subsequently impacting the outcome of interactions. A common approach to the analysis of social interaction is the study of the verbal content transmitted between sender and receiver. However, additional important processes and dynamics are occurring in other domains too, for example in the area of nonverbal behaviour: In a series of studies, we have looked at nonverbal synchrony – the coordination of two persons’ movement patterns – and it‘s association with relationship quality and with the outcome of interactions. Using a computer-based algorithm (Motion Energy Analysis, MEA: Ramseyer & Tschacher, 2011), which automatically quantifies a person‘s body-movement, we were able to objectively calculate nonverbal synchrony in a large number of dyads interacting in various settings. In a first step, we showed that the phenomenon of nonverbal synchrony exists at a level that is significantly higher than expected by chance. In a second step, we ascertained that across different settings – including patient-therapist dyads and healthy dyads – more synchronized movement was associated with better relationship quality and better interactional outcomes. The quality of a relationship is thus embodied by the synchronized movement patterns emerging between partners. Our studies suggest that embodied cognition is a valuable approach to research in social interaction, providing important clues for an improved understanding of interaction dynamics.
Resumo:
During November 2010–February 2011, we used camera traps to estimate the population density of Eurasian lynx Lynx lynx in Ciglikara Nature Reserve, Turkey, an isolated population in southwest Asia. Lynx density was calculated through spatial capture—recapture models. In a sampling eff ort of 1093 camera trap days, we identifi ed 15 independent individuals and estimated a density of 4.20 independent lynx per 100 km2, an unreported high density for this species. Camera trap results also indicated that the lynx is likely to be preying on brown hare Lepus europaeus, which accounted for 63% of the non-target species pictured. As lagomorph populations tend to fl uctuate, the high lynx density recorded in Ciglikara may be temporary and may decline with prey fl uctuation. Therefore we recommend to survey other protected areas in southwestern Turkey where lynx is known or assumed to exist, and continuously monitor the lynx populations with reliable methods in order to understand the populations structure and dynamics, defi ne sensible measures and management plans to conserve this important species.
Resumo:
Short range nucleon-nucleon correlations in nuclei (NN SRC) carry important information on nuclear structure and dynamics. NN SRC have been extensively probed through two-nucleon knock- out reactions in both pion and electron scattering experiments. We report here on the detection of two-nucleon knock-out events from neutrino interactions and discuss their topological features as possibly involving NN SRC content in the target argon nuclei. The ArgoNeuT detector in the Main Injector neutrino beam at Fermilab has recorded a sample of 30 fully reconstructed charged current events where the leading muon is accompanied by a pair of protons at the interaction vertex, 19 of which have both protons above the Fermi momentum of the Ar nucleus. Out of these 19 events, four are found with the two protons in a strictly back-to-back high momenta configuration directly observed in the final state and can be associated to nucleon Resonance pionless mechanisms involving a pre-existing short range correlated np pair in the nucleus. Another fraction (four events) of the remaining 15 events have a reconstructed back-to-back configuration of a np pair in the initial state, a signature compatible with one-body Quasi Elastic interaction on a neutron in a SRC pair. The detection of these two subsamples of the collected (mu- + 2p) events suggests that mechanisms directly involving nucleon-nucleon SRC pairs in the nucleus are active and can be efficiently explored in neutrino-argon interactions with the LAr TPC technology.
Resumo:
Human capital and members of the creative class are bearers of economic growth, yet little is known about exactly what the relevant factors are for the concentration of the highly skilled in a specific place. Tolerance for example is supposed to make the difference between creative and human capital. But does tolerance really make a difference for anybody? And what about other factors: Are they specifically relevant for creative individuals or simply valid for the whole population? This study contributes to the discussion on the highly skilled by investigating whether tolerance, taxes, or other regional amenities contribute to their concentration and dynamics. The results show that tolerance in particular toward immigrants, but also toward same-sex partnerships, is a rather dynamic concept, differs largely between and within functional urban regions, and makes a difference regarding the highly skilled.
Resumo:
Protein-protein interactions are fundamental for most biological processes, such as the formation of cellular structures and enzymatic complexes or in signaling pathways. The identification and characterization of protein-protein interactions are therefore essential for understanding the mechanisms and regulation of biological systems. The organization and dynamics of the cytoskeleton, as well as its anchorage to specific sites in the plasma membrane and organelles, are regulated by the plakins. These structurally related proteins anchor different cytoskeletal networks to each other and/or to other cellular structures. The association of several plakins with intermediate filaments (IFs) is critical for maintenance of the cytoarchitecture. Pathogenic mutations in the genes encoding different plakins can lead to dramatic manifestations, occurring principally in the skin, striated muscle, and/or nervous system, due to cytoskeletal disorganization resulting in abnormal cell fragility. Nevertheless, it is still unclear how plakins bind to IFs, although some general rules are slowly emerging. We here describe in detail a recently developed protein-protein fluorescence binding assay, based on the production of recombinant proteins tagged with green fluorescent protein (GFP) and their use as fluid-phase fluorescent ligands on immobilized IF proteins. Using this method, we have been able to assess the ability of C-terminal regions of GFP-tagged plakin proteins to bind to distinct IF proteins and IF domains. This simple and sensitive technique, which is expected to facilitate further studies in this area, can also be potentially employed for any kind of protein-protein interaction studies.
Resumo:
The second European Zebrafish Principal Investigator (PI) Meeting was held in March, 2012, in Karlsruhe, Germany. It brought together PIs from all over Europe who work with fish models such as zebrafish and medaka to discuss their latest results, as well as to resolve strategic issues faced by this research community. Scientific discussion ranged from the development of new technologies for working with fish models to progress in various fields of research such as injury and repair, disease models, and cell polarity and dynamics. This meeting also marked the establishment of the European Zebrafish Resource Centre (EZRC) at Karlsruhe that in the future will serve as an important focus and community resource for zebrafish- and medaka-based research.
Resumo:
The modulus method introduced by H. Grötzsch yields bounds for a mean distortion functional of quasiconformal maps between two annuli mapping the respective boundary components onto each other. P. P. Belinskiĭ studied these inequalities in the plane and identified the family of all minimisers. Beyond the Euclidean framework, a Grötzsch-Belinskiĭ-type inequality has been previously considered for quasiconformal maps between annuli in the Heisenberg group whose boundaries are Korányi spheres. In this note we show that--in contrast to the planar situation--the minimiser in this setting is essentially unique.