2,623 research outputs found

    Avoiding deontic explosion by contextually restricting aggregation

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    In this paper, we present an adaptive logic for deontic conflicts, called P2.1(r), that is based on Goble's logic SDLaPe-a bimodal extension of Goble's logic P that invalidates aggregation for all prima facie obligations. The logic P2.1(r) has several advantages with respect to SDLaPe. For consistent sets of obligations it yields the same results as Standard Deontic Logic and for inconsistent sets of obligations, it validates aggregation "as much as possible". It thus leads to a richer consequence set than SDLaPe. The logic P2.1(r) avoids Goble's criticisms against other non-adjunctive systems of deontic logic. Moreover, it can handle all the 'toy examples' from the literature as well as more complex ones

    Efeitos Residuais Da Calagem Superficial Em Solo Tropical Com Plantio Direto

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    The objective of this work was to evaluate the long-term effects of the surface application of lime on soil fertility and on the mineral nutrition and grain yield of soybean, and of black oat and sorghum in crop succession. The experiment was carried out on a clayey Oxisol, in a randomized complete block design, with four replicates. Treatments consisted of lime the rates of 0, 1,000, 2,000, and 4,000 kg ha-1, applied in October 2002 and November 2004. Soil samples were collected at five soil layers, down to 0.60-m depth. Surface liming was effective in reducing soil acidity and increasing Ca2+ and Mg2+ contents in the subsurface. Moreover, it increased available phosphorus contents and soil organic matter in the long term (48 to 60 months after the last lime application). Surface liming improved plant nutrition, mainly for N, Ca, and Mg, and increased dry matter production and grain yield of the crops, even in years with regular distribution of rainfall. The greatest productivities of soybean, black oat, and sorghum were obtained with the respective estimated lime doses of 4,000, 2,333, and 3,281 kg ha-1, for shoot dry matter, and of 2,550, 3,555, and over 4,000 kg ha-1, for grain yield.5191633164

    A foundation for real recursive function theory

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    The class of recursive functions over the reals, denoted by REC(R), was introduced by Cristopher Moore in his seminal paper written in 1995. Since then many subsequent investigations brought new results: the class REC(R) was put in relation with the class of functions generated by the General Purpose Analogue Computer of Claude Shannon; classical digital computation was embedded in several ways into the new model of computation; restrictions of REC(R) were proved to represent different classes of recursive functions, e.g., recursive, primitive recursive and elementary functions, and structures such as the Ritchie and the Grzergorczyk hierarchies. The class of real recursive functions was then stratified in a natural way, and REC(R) and the analytic hierarchy were recently recognised as two faces of the same mathematical concept. In this new article, we bring a strong foundational support to the Real Recursive Function Theory, rooted in Mathematical Analysis, in a way that the reader can easily recognise both its intrinsic mathematical beauty and its extreme simplicity. The new paradigm is now robust and smooth enough to be taught. To achieve such a result some concepts had to change and some new results were added

    Fish under pressure: examining behavioural responses of Iberian barbel under simulated hydropeaking with instream structures

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    Research ArticleHydropeaking is the rapid change in the water flow downstream of a hydropower plant, driven by changes in daily electricity demand. These fluctuations may produce negative effects in freshwater fish. To minimize these impacts, previous studies have proposed habitat enhancement structures as potential mitigation measures for salmonids. However, the recommendation of these mitigation measures for cyprinids remains scarce and their effects unknown. In this study, the effects of potential habitat mitigation structures under simulated hydropeaking and base-flow conditions are examined for Iberian barbel (Luciobarbus bocagei) in an indoor flume. Solid triangular pyramids and v-shaped structures were evaluated as potential flow-refuging areas and compared with a configuration without structures. A novel, interdisciplinary approach is applied to investigate individual and group responses to rapidly changing flows, by assessing physiological (glucose and lactate), movement behaviour (structure use, sprints and drifts) and the pressure distribution using a fish-inspired artificial lateral line flow sensor. The major findings of this study are four-fold: 1) Under hydropeaking conditions, the v-shaped structures triggered a lactate response and stimulated individual structure use, whereas solid structures did not elicit physiological adjustments and favoured individual and group structure use. Overall, both solid structures and their absence stimulated sprints and drifts. 2) The hydrodynamic conditions created in hydropeaking did not always reflect increased physiological responses or swimming activity. 3) Each event-structure combination resulted in unique hydrodynamic conditions which were reflected in the different fish responses. 4) The most relevant flow variable measured was the pressure asymmetry, which is caused by the vortex size and shedding frequency of the structures. Considering the non-uniform nature of hydropeaking events, and the observation that the fish responded differently to specific flow event-structure combinations, a diverse set of instream structures should be considered for habitat-based hydropeaking mitigation measures for Iberian barbelinfo:eu-repo/semantics/publishedVersio

    Braess's Paradox in Wireless Networks: The Danger of Improved Technology

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    When comparing new wireless technologies, it is common to consider the effect that they have on the capacity of the network (defined as the maximum number of simultaneously satisfiable links). For example, it has been shown that giving receivers the ability to do interference cancellation, or allowing transmitters to use power control, never decreases the capacity and can in certain cases increase it by Ω(log⁥(Δ⋅Pmax⁥))\Omega(\log (\Delta \cdot P_{\max})), where Δ\Delta is the ratio of the longest link length to the smallest transmitter-receiver distance and Pmax⁥P_{\max} is the maximum transmission power. But there is no reason to expect the optimal capacity to be realized in practice, particularly since maximizing the capacity is known to be NP-hard. In reality, we would expect links to behave as self-interested agents, and thus when introducing a new technology it makes more sense to compare the values reached at game-theoretic equilibria than the optimum values. In this paper we initiate this line of work by comparing various notions of equilibria (particularly Nash equilibria and no-regret behavior) when using a supposedly "better" technology. We show a version of Braess's Paradox for all of them: in certain networks, upgrading technology can actually make the equilibria \emph{worse}, despite an increase in the capacity. We construct instances where this decrease is a constant factor for power control, interference cancellation, and improvements in the SINR threshold (ÎČ\beta), and is Ω(log⁡Δ)\Omega(\log \Delta) when power control is combined with interference cancellation. However, we show that these examples are basically tight: the decrease is at most O(1) for power control, interference cancellation, and improved ÎČ\beta, and is at most O(log⁡Δ)O(\log \Delta) when power control is combined with interference cancellation

    Clinical and socio-demographic profile of patients with venous disease treated in health centers of MaceiĂł (AL), Brazil

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    BACKGROUND: Chronic venous disease (CVD) is to change the system causing a venous valvular incompetence associated with obstruction of flow or not. It affects 10 to 20% of world population, with higher prevalence in females. It presents as the most common symptoms and pain and swelling in advanced form, venous ulcer, and brings functional limitations, social isolation, affecting quality of life. OBJECTIVE: Profiling of patients with CVD, the survey data indicate that clinical and socio-demographic characteristics that may contribute to possible change of habit in the life, who for reasons of work, lack of knowledge and/or instructions had affected their routine by the disease, with consequent decline in their quality of life. METHODS: A descriptive, observational, cross-sectional study that evaluated patients with CVD treated at health centers in MaceiĂł (AL) Brazil, applying a form for collecting data, such as CEAP, Brazil Criterion of Economic Classification Questionnaire and SF-36. RESULTS: The sample consisted of 66 patients with CVD, 83% were female and 17% male. The patients had predominantly aged between 50 and 60 years who were sedentary, assuming prolonged standing, low educational level and economic status, severe clinical disease (symptomatic C6), and quality of life variable. CONCLUSION: The results showed a predominance of females, 50 to 60 years old, with triggering factors and/or aggravating factors for development of CVD as lack of physical activity, low education and low economic income, affecting quality of life.CONTEXTO: A doença venosa crĂŽnica (DVC) consiste em alteração do sistema venoso causando uma incompetĂȘncia valvar associada Ă  obstrução de fluxo ou nĂŁo. Acomete 10 a 20% da população mundial, tendo maior prevalĂȘncia no sexo feminino. Apresenta como sintomas mais comuns dor e edema e na forma avançada, a Ășlcera venosa. Traz limitaçÔes funcionais e isolamento social, afetando a qualidade de vida. OBJETIVO: Traçar o perfil dos portadores de DVC, pelo levantamento de dados clĂ­nicos e sociodemogrĂĄficos que indiquem caracterĂ­sticas que possam contribuir para possĂ­vel mudança de hĂĄbito na vida de pacientes que, por motivos de trabalho, falta de conhecimento e/ou instruçÔes, tiveram sua rotina afetada pela doença, com consequente diminuição da sua qualidade de vida. MÉTODOS: Estudo descritivo, observacional do tipo transversal, sendo avaliados portadores de DVC atendidos em centros de saĂșde de MaceiĂł (AL), aplicando um formulĂĄrio para coleta de dados, como classificação CEAP, CritĂ©rio de Classificação EconĂŽmica Brasil e QuestionĂĄrio SF-36. RESULTADOS: A amostra foi composta por 66 pacientes com DVC; 83% eram do sexo feminino e 17%, do masculino, a faixa etĂĄria predominante foi entre 50 a 60 anos; eram sedentĂĄrios, assumindo ortostatismo prolongado, baixo nĂ­vel de escolaridade e classe econĂŽmica, doença clĂ­nica grave (C6 sintomĂĄtico) e qualidade de vida variĂĄvel. CONCLUSÃO: Os resultados demonstraram predomĂ­nio da doença no sexo feminino, entre 50 a 60 anos de idade, com fatores desencadeadores e/ou agravantes para desenvolvimento da DVC como falta de atividade fĂ­sica, baixo nĂ­vel de escolaridade e baixa renda econĂŽmica, afetando a qualidade de vida.FAL curso de FisioterapiaUniversidade Federal de SĂŁo Paulo (UNIFESP)Universidade Estadual de CiĂȘncias da SaĂșde de AlagoasUNIFESPSciEL

    Representation of Sound Objects within Early-Stage Auditory Areas: A Repetition Effect Study Using 7T fMRI.

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    Environmental sounds are highly complex stimuli whose recognition depends on the interaction of top-down and bottom-up processes in the brain. Their semantic representations were shown to yield repetition suppression effects, i. e. a decrease in activity during exposure to a sound that is perceived as belonging to the same source as a preceding sound. Making use of the high spatial resolution of 7T fMRI we have investigated the representations of sound objects within early-stage auditory areas on the supratemporal plane. The primary auditory cortex was identified by means of tonotopic mapping and the non-primary areas by comparison with previous histological studies. Repeated presentations of different exemplars of the same sound source, as compared to the presentation of different sound sources, yielded significant repetition suppression effects within a subset of early-stage areas. This effect was found within the right hemisphere in primary areas A1 and R as well as two non-primary areas on the antero-medial part of the planum temporale, and within the left hemisphere in A1 and a non-primary area on the medial part of Heschl's gyrus. Thus, several, but not all early-stage auditory areas encode the meaning of environmental sounds

    Advanced hydrogels based on natural macromolecules: chemical routes to achieve mechanical versatility

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    Advances in synthetic routes to chemically modify natural macromolecules such as polysaccharides and proteins have allowed designing functional hydrogels able to tackle current challenges in the biomedical field. Hydrogels are hydrophilic three-dimensional systems able to absorb or retain a large volume of water, prepared from a low percentage of precursor macromolecules. The typical fragile elastic structure of common hydrogel formulations often limits their usage. Three main fabrication strategies involving several compounds or multimodified materials known as double networks, dual-crosslinked networks, and interpenetrating networks have been explored to impart mechanical strength to hydrogels. Widely investigated for synthetic polymers, these approaches allow obtaining added-value hydrogels with a large spectrum of mechanical properties. Advances in the development of such hydrogels with biomacromolecules as main constituent materials have enabled the fabrication of hydrogels with improved key properties for medical use, including biocompatibility, controlled release of active substances and tailored biodegradability, while exploring sustainable sources. This review describes recent advances in the use of proteins, as well as natural and semi-synthetic polymers for the fabrication of hydrogels for biomedical applications. Structures processed via double network, dual-crosslinked, or interpenetrating network strategies are reviewed, and emphasis is given to the type of chemical modifications and reactions, as well as the covalent and non-covalent interactions/bonds involved in those mechanisms.publishe

    The Differentiation and Promotion of Students’ Rights in Portugal

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    This investigation includes a differential study (Study 1) and a quasi-experimental research (Study 2). In Study 1, the objective was to establish to what extent students’ rights existed and analyse the differentiation between students’ rights with Portuguese and immigrant mothers, throughout school years. The sample consisted of 537 students with Portuguese and immigrant mothers, distributed by different school years (7th, 9th and 11th grades). The Children’s Rights Scale (Hart et al., 1996; Veiga, 2001) was used. In Study 2, the purpose was to analyse the effects on students’ rights of the use by teachers of a communicational intervention program, supervised by school psychologists. The sample involved 7th and 9th grade students, in a total of four classes, two forming the experimental groups (n = 36) and two the control groups (n = 43); as in Study 1, the Children’s Rights Scale was used. The results indicated the effectiveness of the communicational intervention program on students’ rights and are consistent with previous studies. An implication is that psychologists and teachers, working together and taking a human rights perspective, may develop an important role in projects to promote the students’ rights

    On the full, strongly exceptional collections on toric varieties with Picard number three

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    We investigate full strongly exceptional collections on smooth, com- plete toric varieties. We obtain explicit results for a large family of varieties with Picard number three, containing many of the families already known. We also describe the relations between the collections and the split of the push forward of the trivial line bundle by the toric Frobenius morphism
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