971 resultados para Obstacle Avoidance
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All higher plants possess multiple phytochrome photoreceptors, with phytochrome A (phyA) being light labile and other members of the family being relatively light stable (phyB-phyE in Arabidopsis [Arabidopsis thaliana]). phyA also differs from other members of the family because it enables plants to deetiolate in far-red light-rich environments typical of dense vegetational cover. Later in development, phyA counteracts the shade avoidance syndrome. Light-induced degradation of phyA favors the establishment of a robust shade avoidance syndrome and was proposed to be important for phyA-mediated deetiolation in far-red light. phyA is ubiquitylated and targeted for proteasome-mediated degradation in response to light. Cullin1 and the ubiquitin E3 ligase CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1) have been implicated in this process. Here, we systematically analyze the requirement of cullins in this process and show that only CULLIN1 plays an important role in light-induced phyA degradation. In addition, the role of COP1 in this process is conditional and depends on the presence of metabolizable sugar in the growth medium. COP1 acts with SUPPRESSOR OF PHYTOCHROME A (SPA) proteins. Unexpectedly, the light-induced decline of phyA levels is reduced in spa mutants irrespective of the growth medium, suggesting a COP1-independent role for SPA proteins.
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A vehicle may leave its travel lane for a number of reasons, such as driver error, poor surface conditions, or avoidance of a collision with another vehicle in the travel lane. When a vehicle leaves the travel lane, pavement edge drop-off poses a potential safety hazard because significant vertical differences between surfaces can affect vehicle stability and reduce a driver’s ability to handle the vehicle. Numerous controlled studies have tested driver response to encountering drop-offs under various conditions, including different speeds, vehicle types, drop-off height and shape, and tire scrubbing versus non-scrubbing conditions. The studies evaluated the drivers’ ability to return to and recover within their own travel lane after leaving the roadway and encountering a drop-off. Many of these studies, however, have used professional drivers as test subjects, so results may not always apply to the population of average drivers. Furthermore, test subjects are always briefed on what generally is to be expected and how to respond; thus, the sense of surprise that a truly naïve driver may experience upon realizing that one or two of his or her tires have just dropped off the edge of the pavement, is very likely diminished. Additionally, the studies were carried out under controlled conditions. The actual impact of pavement edge drop-off on drivers’ ability to recover safely once they leave the roadway, however, is not well understood under actual driving conditions. Additionally, little information is available that quantifies the number or severity of crashes that occur where pavement edge drop-off may have been a contributing factor. Without sufficient information about the frequency of edge drop-off-related crashes, agencies are not fully able to measure the economic benefits of investment decisions, evaluate the effectiveness of different treatments to mitigate edge drop-off, or focus maintenance resources. To address these issues, this report details research to quantify the contribution of pavement edge drop-off to crash frequency and severity. Additionally, the study evaluated federal and state guidance in sampling and addressing pavement edge drop-off and quantified the extent of pavement edge drop-off in two states. This study focused on rural two-lane paved roadways with unpaved shoulders, since they are often high speed facilities (55+ mph), have varying levels of maintenance, and are likely to be characterized by adverse roadway conditions such as narrow lanes or no shoulders.
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Intro. Le syndrome post-thrombotique (SPT) est la complication chronique la plus fréquente après une thrombose veineuse profonde (TVP). Syndrome peu connu, malgré une prévalence de 20-50%, il se caractérise par des symptômes d'insuffisance veineuse chronique apparaissant après une TVP. L'utilisation de bas de compression graduée (BCG) diminue de moitié le risque de développer un SPT. Mais un problème de faible compliance est souvent un obstacle dans la prise en charge. Le but principal de cette étude sera de déterminer le lien entre l'adhérence au BCG et le développement de SPT Méthode. Il s'agit d'une étude cas-témoin, mono-centrique, avec inclusion prospective et consécutive des patients avec une TVP. Les patients recrutés recevront un traitement standard pour une TVP (anticoagulation thérapeutique pendant 3 mois et BCG pour une durée d'un an) et seront suivis sur une année avec 4 visites médicales (V0-V3) et 10 entretiens téléphoniques (I1-I10). A la fin de l'étude, sur la base de l'adhérence au port du BCG, les patients seront divisés en deux groupes: bonne adhérence au traitement (cas) et faible adhérence (témoin). Conclusion. Il est certain que ce sujet a besoin de recherches pour mieux comprendre le développement, trouver une prévention et des traitements efficaces et acceptables afin d'améliorer leur qualité de vie des patients.
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BACKGROUND: Little is known about engagement in multiple health behaviours in childhood cancer survivors. METHODS: Using latent class analysis, we identified health behaviour patterns in 835 adult survivors of childhood cancer (age 20-35 years) and 1670 age- and sex-matched controls from the general population. Behaviour groups were determined from replies to questions on smoking, drinking, cannabis use, sporting activities, diet, sun protection and skin examination. RESULTS: The model identified four health behaviour patterns: 'risk-avoidance', with a generally healthy behaviour; 'moderate drinking', with higher levels of sporting activities, but moderate alcohol-consumption; 'risk-taking', engaging in several risk behaviours; and 'smoking', smoking but not drinking. Similar proportions of survivors and controls fell into the 'risk-avoiding' (42% vs 44%) and the 'risk-taking' cluster (14% vs 12%), but more survivors were in the 'moderate drinking' (39% vs 28%) and fewer in the 'smoking' cluster (5% vs 16%). Determinants of health behaviour clusters were gender, migration background, income and therapy. CONCLUSION: A comparable proportion of childhood cancer survivors as in the general population engage in multiple health-compromising behaviours. Because of increased vulnerability of survivors, multiple risk behaviours should be addressed in targeted health interventions.
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We develop a setting with weak intellectual property rights, where firms' boundaries, location and knowledge spillovers are endogenous. We have two main results. The first one is that, if communication costs increase with distance, entrepreneurs concerned about information leakage have a benefit from locating away from the industry center: distance is an obstacle to collusive trades between members andnon-members. The second result is that we identify a trade-off for the entrepreneur between owning a facility (controlling all its characteristics) and sharing a facility with a {\it non-member} (an agent not involved in production), therefore losing control over some of its characteristics. We focus on ``location" as the relevant characteristic of the facility, but location can be used as a spatial metaphor for other relevant characteristics of the facility. For theentrepreneur, sharing the facility with non-members implies that the latter, as co-owners, know the location (even if they do not have access to it). Knowledge of the location for the co-owners facilitates collusion with employees, what increases leakage. The model yields a benefit for new plants from spatial dispersion (locating at the periphery of the industry), particularly so for new plants of new firms.We relate this result with recent empirical findings on the dynamics of industry location.
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The emergence of host-races within aphids may constitute an obstacle to pest management by means of plant resistance. There are examples of host-races within cereals aphids, but their occurrence in Rose Grain Aphid, Metopolophium dirhodum (Walker, 1849), has not been reported yet. In this work, RAPD markers were used to assess effects of the hosts and geographic distance on the genetic diversity of M. dirhodum lineages. Twenty-three clones were collected on oats and wheat in twelve localitites of southern Brazil. From twenty-seven primers tested, only four primers showed polymorphisms. Fourteen different genotypes were revealed by cluster analysis. Five genotypes were collected only on wheat; seven only on oats and two were collected in both hosts. Genetic and geographical distances among all clonal lineages were not correlated. Analysis of molecular variance showed that some molecular markers are not randomly distributed among clonal lineages collected on oats and on wheat. These results suggest the existence of host-races within M. dirhodum, which should be further investigated using a combination of ecological and genetic data.
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Both individual socio-cultural determinants such as selected parental characteristics (migrant background, low educational level and workload) as well as the regional environment are related to childhood overweight and physical activity (PA). The purpose of the study was to compare the impact of distinct socio-cultural determinants such as the regional environment and selected parental characteristics on adiposity, PA and motor skills in preschool children. Forty preschools (N = 542 children) of two culturally different urban regions (German and French speaking part of Switzerland) participated in the study (Ballabeina Study). Outcome measures included adiposity (BMI and skinfold thickness), objectively measured sedentary activities and PA (accelerometers) and agility performance (obstacle course). Parental characteristics (migrant status, educational level and workload) were assessed by questionnaire. Children from the French speaking areas had higher adiposity, lower levels of total and of more intense PA, were more sedentary and less agile than children from the German speaking regions (percent differences for all outcome parameters except for BMI ≥10%; all p ≤ 0.04). Differences in skinfold thickness, sedentary activities and agility, but not in PA, were also found between children of Swiss and migrant parents, though they were ≤8% (p ≤ 0.02). While paternal workload had no effect, maternal workload and parental education resulted in differences in some PA measures and/or agility performance (percent differences in both: ≤9%, p ≤ 0.008), but not in adiposity or sedentary activities (p = NS). Regional differences in skinfold thickness, PA, sedentary activities and agility performance persisted after adjustment for parental socio-cultural characteristics, parental BMI and, where applicable, children's skinfolds (all p ≤ 0.01). The regional environment, especially the broader social environment, plays a prominent role in determining adiposity, PA and motor skills of young children and should be implicated in the prevention of obesity and promotion of PA in children. clinicaltrials.gov NCT00674544.
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We combined mark-and-recapture studies with genetic techniques of parentage assignment to evaluate the interactions between mating, dispersal, and inbreeding, in a free-ranging population of Crocidura russula. We found a pattern of limited and female-biased dispersal, followed by random mating within individual neighborhoods. This results in significant inbreeding at the population level: mating among relatives occurs more often than random, and F(IT) analyses reveal significant deficits in heterozygotes. However, related mating partners were not less fecund, and inbred offspring had no lower lifetime reproductive output. Power analyses show these negative results to be quite robust. Absence of phenotypic evidence of inbreeding depression might result from a history of purging: local populations are small and undergo disequilibrium gene dynamics. Dispersal is likely caused by local saturation and (re)colonization of empty breeding sites, rather than inbreeding avoidance.
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O presente trabalho investiga a tributação dos serviços em Cabo Verde, trata-se de uma questão importante do ponto de vista financeiro, uma vez que a economia aberta e insular de Cabo Verde é uma grande consumidora de serviços prestados por operadores económicos não residentes. Por outro lado trata de uma questão interessante do ponto de vista jurídico, porque parece actualmente faltar norma de incidência que permite a sujeição destes rendimentos ao Imposto Único sobre os Rendimentos Cabo-verdiano. Em face disto poder-se-ia porventura afirmar que as normas de incidência que servem para fundamentar a tributação dos rendimentos derivados de prestação de serviços a não residentes se encontram nas disposições orçamentais que fixam a própria taxa liberatória de 20% aplicável ao rendimento auferido por não residentes, mesmo que não tenham estabelecimentos estáveis. De resto, não é com base no regulamento do IUR mas com base nas leis do Orçamentos do Estado que a administração fiscal Cabo-verdiana tem vindo a proceder á liquidação deste imposto. As taxas liberatórias previstas nas leis orçamentais não podem nunca aplicar-se a rendimentos que se encontrem fora do âmbito de incidência objectiva, subjectiva ou territorial do IUR. Depois de estudado o tratamento que o direito interno cabo-verdiano faz dos rendimentos derivados de prestação de serviços vale a pena olhar brevemente também ao tratamento que eles merecem no contexto do direito internacional e, muito em particular, da convenção para evitar a Dupla Tributação (CDT) em matéria de imposto sobre o rendimento e prevenir a evasão fiscal, celebrada entre Cabo Verde e Portugal no ano de 1999 e actualmente em vigor.
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No momento em que se verifica algumas reformas no sistema educativo cabo-verdiano, torna-se necessário analisar a questão da formação dos professores de forma a prepará-los para a função que têm que desempenhar. Com a realização deste estudo, pretende-se diagnosticar percursos e necessidade de formação dos professores na área das Tecnologias de Informação e Comunicação (TIC), bem como descrever o sentido de competência (auto-eficácia) dos professores na utilização das tecnologias, concretamente à mobilização dos mesmos no processo ensino e aprendizagem. Tendo em conta os objetivos do estudo, optou-se por utilizar uma metodologia de natureza quantitativa. O estudo integra a participação de 87 professores. Escolheu-se a técnica de inquérito, realizando um inquérito por questionário com questões fechadas aos professores da Escola Secundária Abílio Duarte situada na Cidade da Praia, ilha de Santiago, Cabo Verde. A revisão da literatura permitiu verificar que já foram desenvolvidas iniciativas, a nível nacional, para a implementação das TIC nas escolas. Atualmente destaca-se o programa Mundu Novu do governo de Cabo Verde, coordenado pelo Ministério da Educação, que tem como objetivo modernizar o processo de ensino através da utilização das TIC criando um novo paradigma de ensino interativo. Os resultados apontam para a progressiva utilização das TIC nas atividades dos professores que revelam um moderado sentido de auto-eficácia de utilização das TIC. A formação de professores é apontada como o principal obstáculo à integração e utilização educativa das TIC.
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Background: The debate about a possible relationship between aerobic fitness and motor skills with cognitive development in children has recently re-emerged, because of the decrease in children's aerobic fitness and the concomitant pressure of schools to enhance cognitive performance. As the literature in young children is scarce, we examined the cross-sectional and longitudinal relationship of aerobic fitness and motor skills with spatial working memory and attention in preschool children.Methods: Data from 245 ethnically diverse preschool children (mean age: 5.2 (0.6) years, girls: 49.4%) analyzed at baseline and 9 months later. Assessments included aerobic fitness (20 m shuttle run) and motor skills with agility (obstacle course) and dynamic balance (balance beam). Cognitive parameters included spatial working memory (IDS) and attention (KHV-VK). All analyses were adjusted for age, sex, BMI, migration status, parental education, native language and linguistic region. Longitudinal analyses were additionally adjusted for the respective baseline value.Results: In the cross-sectional analysis, aerobic fitness was associated with better attention (r = 0.16, p = 0.03). A shorter time in the agility test was independently associated with a better performance both in working memory (r = -0.17, p = 0.01) and in attention (r = -0.20, p = 0.01). In the longitudinal analyses, baseline aerobic fitness was independently related to improvements in attention (r = 0.16, p = 0.03), while baseline dynamic balance was associated with improvements in working memory (r = 0.15, p = 0.04).Conclusions: In young children, higher baseline aerobic fitness and motor skills were related to a better spatial working memory and/or attention at baseline, and to some extent also to their future improvements over the following 9 months.
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Executive SummaryIn Nepal, landslides are one of the major natural hazards after epidemics, killing over 100 persons per year. However, this figure is an underreported reflection of the actual impact that landslides have on livelihoods and food security in rural Nepal. With predictions of more intense rainfall patterns, landslide occurrence in the Himalayas is likely to increase and continue to be one of the major impediments to development. Due to the remoteness of many localities and lack of resources, responsibilities for disaster preparedness and response in mountain areas usually lie with the communities themselves. Everyday life is full of risk in mountains of Nepal. This is why mountain populations, as well as other populations living in harsh conditions have developed a number of coping strategies for dealing with adverse situations. Perhaps due to the dispersed and remote nature of landslides in Nepal, there have been few studies on vulnerability, coping- and mitigation strategies of landslide affected populations. There are also few recommendations available to guide authorities and populations how to reduce losses due to landslides in Nepal, and even less so, how to operationalize resilience and vulnerability.Many policy makers, international donors, NGOs and national authorities are currently asking what investments are needed to increase the so-called 'resilience' of mountain populations to deal with climate risks. However, mountain populations are already quite resilient to seasonal fluctuations, temperature variations, rainfall patterns and market prices. In spite of their resilience, they continue to live in places at risk due to high vulnerability caused by structural inequalities: access to land, resources, markets, education. This interdisciplinary thesis examines the concept of resilience by questioning its usefulness and validity as the current goal of international development and disaster risk reduction policies, its conceptual limitations and its possible scope of action. The goal of this study is two-fold: to better define and distinguish factors and relationships between resilience, vulnerability, capacities and risk; and to test and improve a participatory methodology for evaluating landslide risk that can serve as a guidance tool for improving community-based disaster risk reduction. The objective is to develop a simple methodology that can be used by NGOs, local authorities and communities to reduce losses from landslides.Through its six case studies in Central-Eastern Nepal, this study explores the relation between resilience, vulnerability and landslide risk based on interdisciplinary methods, including geological assessments of landslides, semi-structured interviews, focus groups and participatory risk mapping. For comparison, the study sites were chosen in Tehrathum, Sunsari and Dolakha Districts of Central/Eastern Nepal, to reflect a variety of landslide types, from chronic to acute, and a variety of communities, from very marginalized to very high status. The study uses the Sustainable Livelihoods Approach as its conceptual basis, which is based on the notion that access and rights to resources (natural, human/institutional, economic, environmental, physical) are the basis for coping with adversity, such as landslides. The study is also intended as a contribution to the growing literature and practices on Community Based Disaster Risk Reduction specifically adapted to landslide- prone areas.In addition to the six case studies, results include an indicator based methodology for assessing and measuring vulnerability and resilience, a composite risk assessment methodology, a typology of coping strategies and risk perceptions and a thorough analysis of the relation between risk, vulnerability and resilience. The methodology forassessing vulnerability, resilience and risk is relatively cost-effective and replicable in a low-data environment. Perhaps the major finding is that resilience is a process that defines a community's (or system's) capacity to rebound following adversity but it does not necessarily reduce vulnerability or risk, which requires addressing more structural issues related to poverty. Therefore, conclusions include a critical view of resilience as a main goal of international development and disaster risk reduction policies. It is a useful concept in the context of recovery after a disaster but it needs to be addressed in parallel with vulnerability and risk.This research was funded by an interdisciplinary grant (#26083591) from the Swiss National Science Foundation for the period 2009-2011 and a seed grant from the Faculty of Geosciences and Environment at the University of Lausanne in 2008.Résumé en françaisAu Népal, les glissements de terrain sont un des aléas les plus dévastateurs après les épidémies, causant 100 morts par an. Pourtant, ce chiffre est une sous-estimation de l'impact réel de l'effet des glissements sur les moyens de subsistance et la sécurité alimentaire au Népal. Avec des prévisions de pluies plus intenses, l'occurrence des glissements dans les Himalayas augmente et présente un obstacle au développement. Du fait de l'éloignement et du manque de ressources dans les montagnes au Népal, la responsabilité de la préparation et la réponse aux catastrophes se trouve chez les communautés elles-mêmes. Le risque fait partie de la vie quotidienne dans les montagnes du Népal. C'est pourquoi les populations montagnardes, comme d'autres populations vivant dans des milieux contraignants, ont développé des stratégies pour faire face aux situations défavorables. Peu d'études existent sur la vulnérabilité, ceci étant probablement dû à l'éloignement et pourtant, les stratégies d'adaptation et de mitigation des populations touchées par des glissements au Népal existent.Beaucoup de décideurs politiques, bailleurs de fonds, ONG et autorités nationales se demandent quels investissements sont nécessaires afin d'augmenter la 'resilience' des populations de montagne pour faire face aux changements climatiques. Pourtant, ces populations sont déjà résilientes aux fluctuations des saisons, des variations de température, des pluies et des prix des marchés. En dépit de leur résilience, ils continuent de vivre dans des endroits à fort risque à cause des vulnérabilités créées par les inégalités structurelles : l'accès à la terre, aux ressources, aux marchés et à l'éducation. Cette thèse interdisciplinaire examine le concept de la résilience en mettant en cause son utilité et sa validité en tant que but actuel des politiques internationales de développement et de réduction des risques, ainsi que ses limitations conceptuelles et ses possibles champs d'action. Le but de cette étude est double : mieux définir et distinguer les facteurs et relations entre la résilience, la vulnérabilité, les capacités et le risque ; Et tester et améliorer une méthode participative pour évaluer le risque des glissements qui peut servir en tant qu'outil indicatif pour améliorer la réduction des risques des communautés. Le but est de développer une méthodologie simple qui peut être utilisée par des ONG, autorités locales et communautés pour réduire les pertes dues aux glissements.A travers les études de cas au centre-est du Népal, cette étude explore le rapport entre la résilience, la vulnérabilité et les glissements basée sur des méthodes interdisciplinaires ; Y sont inclus des évaluations géologiques des glissements, des entretiens semi-dirigés, des discussions de groupes et des cartes de risques participatives. Pour la comparaison, les zones d'études ont été sélectionnées dans les districts de Tehrathum, Sunsari et Dolakha dans le centre-est du Népal, afin de refléter différents types de glissements, de chroniques à urgents, ainsi que différentes communautés, variant de très marginalisées à très haut statut. Pour son cadre conceptuel, cette étude s'appuie sur l'approche de moyens de subsistance durable, qui est basée sur les notions d'accès et de droit aux ressources (naturelles, humaines/institutionnelles, économiques, environnementales, physiques) et qui sont le minimum pour faire face à des situations difficiles, comme des glissements. Cette étude se veut aussi une contribution à la littérature et aux pratiques en croissantes sur la réduction des risques communautaires, spécifiquement adaptées aux zones affectées par des glissements.En plus des six études de cas, les résultats incluent une méthodologie basée sur des indicateurs pour évaluer et mesurer la vulnérabilité et la résilience, une méthodologie sur le risque composé, une typologie de stratégies d'adaptation et perceptions des risques ainsi qu'une analyse fondamentale de la relation entre risque, vulnérabilité et résilience. Les méthodologies pour l'évaluation de la vulnérabilité, de la résilience et du risque sont relativement peu coûteuses et reproductibles dans des endroits avec peu de données disponibles. Le résultat probablement le plus pertinent est que la résilience est un processus qui définit la capacité d'une communauté (ou d'un système) à rebondir suite à une situation défavorable, mais qui ne réduit pas forcement la vulnérabilité ou le risque, et qui requiert une approche plus fondamentale s'adressant aux questions de pauvreté. Les conclusions incluent une vue critique de la résilience comme but principal des politiques internationales de développement et de réduction des risques. C'est un concept utile dans le contexte de la récupération après une catastrophe mais il doit être pris en compte au même titre que la vulnérabilité et le risque.Cette recherche a été financée par un fonds interdisciplinaire (#26083591) du Fonds National Suisse pour la période 2009-2011 et un fonds de préparation de recherches par la Faculté des Géosciences et Environnement à l'Université de Lausanne en 2008.
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Pollinator guild organization and its consequences for reproduction in three synchronopatric species of Tibouchina (Melastomataceae). In co-flowering plant species, pollinator sharing can result in interspecific pollen transfer and fecundity reduction. Competition will be relaxed whenever there is a large amount of initial pollen supply or if each plant species occupies different habitat patches. Reproduction in Tibouchina cerastifolia (Naudin) Cogn., T. clinopodifolia (DC.) Cogn. and T. gracilis (Bonpl.) Cogn. was studied in an area of Atlantic rainforest to examine whether synchronopatry induces time partitioning among pollinator species. Eleven bee species comprised the pollinator guild. Among pollinators, there were overlaps in bee species composition and in flower visitation time. Direct competition for pollen in Tibouchina Aubl. at the study site seems to lead to different activity periods among the bee species, in which Bombus pauloensis Friese,1913 was most active earlier, while the other species were active later in the day. Bombus pauloensis, the largest bee species recorded on Tibouchina flowers, was the most important and efficient pollinator. This species harvested pollen before the other species and had the shortest handling time. The plants reproduced sexually by selfing or outcrossing, and hybridization was not avoided by incompatibility reactions at the style. The avoidance of direct competition for pollen and no pollinator partitioning among the synchronopatric species of Tibouchina may reflect a facilitative interaction among these pioneer plants.
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OBJECTIVE: To provide an update to the original Surviving Sepsis Campaign clinical management guidelines, "Surviving Sepsis Campaign guidelines for management of severe sepsis and septic shock," published in 2004. DESIGN: Modified Delphi method with a consensus conference of 55 international experts, several subsequent meetings of subgroups and key individuals, teleconferences, and electronic-based discussion among subgroups and among the entire committee. This process was conducted independently of any industry funding. METHODS: We used the GRADE system to guide assessment of quality of evidence from high (A) to very low (D) and to determine the strength of recommendations. A strong recommendation indicates that an intervention's desirable effects clearly outweigh its undesirable effects (risk, burden, cost), or clearly do not. Weak recommendations indicate that the tradeoff between desirable and undesirable effects is less clear. The grade of strong or weak is considered of greater clinical importance than a difference in letter level of quality of evidence. In areas without complete agreement, a formal process of resolution was developed and applied. Recommendations are grouped into those directly targeting severe sepsis, recommendations targeting general care of the critically ill patient that are considered high priority in severe sepsis, and pediatric considerations. RESULTS: Key recommendations, listed by category, include: early goal-directed resuscitation of the septic patient during the first 6 hrs after recognition (1C); blood cultures prior to antibiotic therapy (1C); imaging studies performed promptly to confirm potential source of infection (1C); administration of broad-spectrum antibiotic therapy within 1 hr of diagnosis of septic shock (1B) and severe sepsis without septic shock (1D); reassessment of antibiotic therapy with microbiology and clinical data to narrow coverage, when appropriate (1C); a usual 7-10 days of antibiotic therapy guided by clinical response (1D); source control with attention to the balance of risks and benefits of the chosen method (1C); administration of either crystalloid or colloid fluid resuscitation (1B); fluid challenge to restore mean circulating filling pressure (1C); reduction in rate of fluid administration with rising filing pressures and no improvement in tissue perfusion (1D); vasopressor preference for norepinephrine or dopamine to maintain an initial target of mean arterial pressure > or = 65 mm Hg (1C); dobutamine inotropic therapy when cardiac output remains low despite fluid resuscitation and combined inotropic/vasopressor therapy (1C); stress-dose steroid therapy given only in septic shock after blood pressure is identified to be poorly responsive to fluid and vasopressor therapy (2C); recombinant activated protein C in patients with severe sepsis and clinical assessment of high risk for death (2B except 2C for post-operative patients). In the absence of tissue hypoperfusion, coronary artery disease, or acute hemorrhage, target a hemoglobin of 7-9 g/dL (1B); a low tidal volume (1B) and limitation of inspiratory plateau pressure strategy (1C) for acute lung injury (ALI)/acute respiratory distress syndrome (ARDS); application of at least a minimal amount of positive end-expiratory pressure in acute lung injury (1C); head of bed elevation in mechanically ventilated patients unless contraindicated (1B); avoiding routine use of pulmonary artery catheters in ALI/ARDS (1A); to decrease days of mechanical ventilation and ICU length of stay, a conservative fluid strategy for patients with established ALI/ARDS who are not in shock (1C); protocols for weaning and sedation/analgesia (1B); using either intermittent bolus sedation or continuous infusion sedation with daily interruptions or lightening (1B); avoidance of neuromuscular blockers, if at all possible (1B); institution of glycemic control (1B) targeting a blood glucose < 150 mg/dL after initial stabilization ( 2C ); equivalency of continuous veno-veno hemofiltration or intermittent hemodialysis (2B); prophylaxis for deep vein thrombosis (1A); use of stress ulcer prophylaxis to prevent upper GI bleeding using H2 blockers (1A) or proton pump inhibitors (1B); and consideration of limitation of support where appropriate (1D). Recommendations specific to pediatric severe sepsis include: greater use of physical examination therapeutic end points (2C); dopamine as the first drug of choice for hypotension (2C); steroids only in children with suspected or proven adrenal insufficiency (2C); a recommendation against the use of recombinant activated protein C in children (1B). CONCLUSION: There was strong agreement among a large cohort of international experts regarding many level 1 recommendations for the best current care of patients with severe sepsis. Evidenced-based recommendations regarding the acute management of sepsis and septic shock are the first step toward improved outcomes for this important group of critically ill patients.
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Extinction, recolonization, and local adaptation are common in natural spatially structured populations. Understanding their effect upon genetic variation is important for systems such as genetically modified organism management or avoidance of drug resistance. Theoretical studies on the effect of extinction and recolonization upon genetic variance started appearing in the 1970s, but the role of local adaptation still has no good theoretical basis. Here we develop a model of a haploid species in a metapopulation in which a locally adapted beneficial allele is introduced. We study the effect of different spatial patterns of local adaptation, and different metapopulation dynamics, upon the fixation probability of the beneficial allele. Controlling for the average selection pressure, we find that a small area of positive selection can significantly increase the global probability of fixation. However, local adaptation becomes less important as extinction rate increases. Deme extinction and recolonization have a spatial smoothing effect that effectively reduces spatial variation in fitness.