988 resultados para peaks-over-threshold


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Pest Control is treated as a economic problem. The social and the private perspectives differ due to the consideration of the environmental and social impacts as well as technical aspects such as resistance, resurgence and secondary pests. A mathematical model is developed to determine and compare the social and the private optimum control strategies (which define the Economic Thereshold Levels) for the velvetbean caterpillar on soybeans in Brazil. The crop/pest system incorporates effects of predators and parasites, the soybean natural capacity to compensate for injury and the pesticide effects on both pests and its natural enemies; in the social case, the environmental and social impacts and the effects of pest resistance to the pesticide are incorporated. Consideration of density dependence, weather effects, randomnes of pest attack and risk aversion are discussed. The results can be compared with current control practices and IPM programme recomendations.

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Fault tolerance has become a major issue for computer and software engineers because the occurrence of faults increases the cost of using a parallel computer. RADIC is the fault tolerance architecture for message passing systems which is transparent, decentralized, flexible and scalable. This master thesis presents the methodology used to implement the RADIC architecture over Open MPI, a well-know large-used message passing library. This implementation kept the RADIC architecture characteristics. In order to validate the implementation we have executed a synthetic ping program, besides, to evaluate the implementation performance we have used the NAS Parallel Benchmarks. The results prove that the RADIC architecture performance depends on the communication pattern of the parallel application which is running. Furthermore, our implementation proves that the RADIC architecture could be implemented over an existent message passing library.

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Partant de la réception internationale du film Le Roman d'un tricheur de Sacha Guitry dans laquelle la voix du cinéaste est fréquemment rapprochée de celle du "bonimenteur" de l'époque muette, cette étude examine les particularités de ce film en termes de positionnement du narrateur over par rapport aux images et par rapport au spectateur. Une filiation est posée entre ce film et Providence de Resnais au niveau des manifestations de l'oralité: là aussi, le narrateur occupe la place d'instigateur du monde filmique et de spectateur des images qu'il commente.

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We give sufficient conditions for homotopical localization functors to preserve algebras over coloured operads in monoidal model categories. Our approach encompasses a number of previous results about preservation of structures under localizations, such as loop spaces or infinite loop spaces, and provides new results of the same kind. For instance, under suitable assumptions, homotopical localizations preserve ring spectra (in the strict sense, not only up to homotopy), modules over ring spectra, and algebras over commutative ring spectra, as well as ring maps, module maps, and algebra maps. It is principally the treatment of module spectra and their maps that led us to the use of coloured operads (also called enriched multicategories) in this context.

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Sleep spindles are synchronized 11-15 Hz electroencephalographic (EEG) oscillations predominant during nonrapid-eye-movement sleep (NREMS). Rhythmic bursting in the reticular thalamic nucleus (nRt), arising from interplay between Ca(v)3.3-type Ca(2+) channels and Ca(2+)-dependent small-conductance-type 2 (SK2) K(+) channels, underlies spindle generation. Correlative evidence indicates that spindles contribute to memory consolidation and protection against environmental noise in human NREMS. Here, we describe a molecular mechanism through which spindle power is selectively extended and we probed the actions of intensified spindling in the naturally sleeping mouse. Using electrophysiological recordings in acute brain slices from SK2 channel-overexpressing (SK2-OE) mice, we found that nRt bursting was potentiated and thalamic circuit oscillations were prolonged. Moreover, nRt cells showed greater resilience to transit from burst to tonic discharge in response to gradual depolarization, mimicking transitions out of NREMS. Compared with wild-type littermates, chronic EEG recordings of SK2-OE mice contained less fragmented NREMS, while the NREMS EEG power spectrum was conserved. Furthermore, EEG spindle activity was prolonged at NREMS exit. Finally, when exposed to white noise, SK2-OE mice needed stronger stimuli to arouse. Increased nRt bursting thus strengthens spindles and improves sleep quality through mechanisms independent of EEG slow waves (<4 Hz), suggesting SK2 signaling as a new potential therapeutic target for sleep disorders and for neuropsychiatric diseases accompanied by weakened sleep spindles.

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Labour market regulations aimed at enhancing job-security are dominant in several OECD countries. These regulations seek to reduce dismissals of workers and fluctuations in employment. The main theoretical contribution is to gauge the effects of such regulations on labour demand across establishment sizes. In order to achieve this, we investigate an optimising model of labour demand under uncertainty through the application of real option theory. We also consider other forms of employment which increase the flexibility of the labour market. In particular, we are modelling the contribution of temporary employment agencies (Zeitarbeit) allowing for quick personnel adjustments in client firms. The calibration results indicate that labour market rigidities may be crucial for understanding sluggishness in firms´ labour demand and the emergence and growth of temporary work.

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BACKGROUND: The number of requests to pre-hospital emergency medical services (PEMS) has increased in Europe over the last 20 years, but epidemiology of PEMS interventions has little be investigated. The aim of this analysis was to describe time trends of PEMS activity in a region of western Switzerland. METHODS: Use of data routinely and prospectively collected for PEMS intervention in the Canton of Vaud, Switzerland, from 2001 to 2010. This Swiss Canton comprises approximately 10% of the whole Swiss population. RESULTS: We observed a 40% increase in the number of requests to PEMS between 2001 and 2010. The overall rate of requests was 35/1000 inhabitants for ambulance services and 10/1000 for medical interventions (SMUR), with the highest rate among people aged ≥ 80. Most frequent reasons for the intervention were related to medical problems, predominantly unconsciousness, chest pain respiratory distress, or cardiac arrest, whereas severe trauma interventions decreased over time. Overall, 89% were alive after 48 h. The survival rate after 48 h increased regularly for cardiac arrest or myocardial infarction. CONCLUSION: Routine prospective data collection of prehospital emergency interventions and monitoring of activity was feasible over time. The results we found add to the understanding of determinants of PEMS use and need to be considered to plan use of emergency health services in the near future. More comprehensive analysis of the quality of services and patient safety supported by indicators are also required, which might help to develop prehospital emergency services and new processes of care.

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En aquesta memòria l'autor, fent servir un enfoc modern, redissenya i implementa la plataforma que una empresa de telecomunicacions del segle 21 necessita per poder donar serveis de telefonia i comunicacions als seus usuaris i clients. Al llarg d'aquesta exposició es condueix al lector des d'una fase inicial de disseny fins a la implementació i posada en producció del sistema final desenvolupat, centrant-nos en solucionar les necessitats actuals que això implica. Aquesta memòria cubreix el software, hardware i els processos de negoci associats al repte de fer realitat aquest objectiu, i presenta al lector les múltiples tecnologies emprades per aconseguir-ho, fent emfàsi en la convergència actual de xarxes cap al concepte de xarxes IP i basant-se en aquesta tendència i utilitzant aquesta tecnologia de veu sobre IP per donar forma a la plataforma que finalment, de forma pràctica, es posa en producció.

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Changes in climate policy have large influence on businesses. Firms anticipate and respond to such changes, but what if they have already engaged in a longterm relationship with other firms or customers at the time of policy change? For example, coal supply to power stations is typically based on long-term contracts, while the nature of the buyer-supplier relationship may well be affected substantially by climate regulations. However, there has been little evidence on whether or how firms amend their contractual agreements in response to a change in policy.

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L'auteur analyse dans une perspective narratologique trois films de Joseph L. Mankiewicz réalisés entre 1949 et 1954 (A Letter to Three Wives, All about Eve et The Barefoot Contessa), afin d'observer les particularités qui résultent du recours à un ou plusieurs narrateurs (ou narratrices) s'exprimant en voix over. L'accent est mis sur les implications de l'organisation énonciative complexe de ces productions cinématographiques en termes de relation du film au spectateur et de représentation des rapports de genre. Ces études de cas permettent de nuancer certains acquis issus du champ des théories de l'énonciation. Dans ces films où les voix over sont proférées par des acteurs qui incarnent par ailleurs un personnage visualisé, certaines interactions sont observables - interprétées notamment comme des relations de pouvoir - entre le statut des narrateurs et le niveau diégétique. La matérialité sonore est prise en compte dans le cas particulier de Letter to Three Wives, où la voix se transforme en bruit. Cet « effet spécial » est l'occasion de discuter un modèle « impersonnel » de l'énonciation filmique qui intègre, tout en tenant compte de la dimension technologique de l'enregistrement sonore, le pouvoir fondamentalement humanisant des manifestations vocales.

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Background: Alliance evolutions, i.e. ruptures and resolutions over the course of psychotherapy, have been shown to be important descriptive features in different forms of psychotherapy, and in particular in psychodynamic psychotherapy. This case study of a client presenting elements of adjustment disorder undergoing short-term dynamic psychotherapy is drawn from a systematic naturalistic study and aims at illustrating, on a session-by-session-level, the processes of alliance ruptures and resolutions, by comparing both the client's and the therapist's perspectives. Method: Two episodes of alliance evolution were more fully studied, in relation to the evolution of transference, as well as the client's defensive functioning and core conflictual theme. These concepts were measured by means of valid, reliable observer-rater methods, based on session transcripts: the Defense Mechanisms Rating Scales (DMRS) for defensive functioning and the Core Conflictual Relationship Theme (CCRT) for the conflicts. Alliance was measured after each session using the Helping Alliance questionnaire (HAq-II). Results: The results indicated that these episodes of alliance rupture and resolutions may be understood as key moments of the whole therapeutic process reflecting the client's main relationship stakes. Illustrations are provided based on the client's in-session processes and related to the alliance development over the course of the entire therapy.

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Traditionally, it is assumed that the population size of cities in a country follows a Pareto distribution. This assumption is typically supported by nding evidence of Zipf's Law. Recent studies question this nding, highlighting that, while the Pareto distribution may t reasonably well when the data is truncated at the upper tail, i.e. for the largest cities of a country, the log-normal distribution may apply when all cities are considered. Moreover, conclusions may be sensitive to the choice of a particular truncation threshold, a yet overlooked issue in the literature. In this paper, then, we reassess the city size distribution in relation to its sensitivity to the choice of truncation point. In particular, we look at US Census data and apply a recursive-truncation approach to estimate Zipf's Law and a non-parametric alternative test where we consider each possible truncation point of the distribution of all cities. Results con rm the sensitivity of results to the truncation point. Moreover, repeating the analysis over simulated data con rms the di culty of distinguishing a Pareto tail from the tail of a log-normal and, in turn, identifying the city size distribution as a false or a weak Pareto law.

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This paper analyses optimal income taxes over the business cycle under a balanced-budget restriction, for low, middle and high income households. A model incorporating capital-skill complementarity in production and differential access to capital and labour markets is developed to capture the cyclical characteristics of the US economy, as well as the empirical observations on wage (skill premium) and wealth inequality. We .nd that the tax rate for high income agents is optimally the least volatile and the tax rate for low income agents the least countercyclical. In contrast, the path of optimal taxes for the middle income group is found to be very volatile and counter-cyclical. We further find that the optimal response to output-enhancing capital equipment technology and spending cuts is to increase the progressivity of income taxes. Finally, in response to positive TFP shocks, taxation becomes more progressive after about two years.

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We defi ne a solution concept, perfectly contracted equilibrium, for an intertemporal exchange economy where agents are simultaneously price takers in spot commodity markets while engaging in non-Walrasian contracting over future prices. In a setting with subjective uncertainty over future prices, we show that perfectly contracted equi- librium outcomes are a subset of Pareto optimal allocations. It is a robust possibility for perfectly contracted equilibrium outcomes to di er from Arrow-Debreu equilibrium outcomes. We show that both centralized banking and retrading with bilateral contracting can lead to perfectly contracted equilibria.