Harvesting optimization with stochastic differential equations models: is the optimal enemy of the good?

We can describe the size evolution of a harvested population in a randomly varying environment using stochastic differential equations. Previously, we have compared the profit performance of four harvesting policies: (i) optimal variable effort policy, based on variable effort; (ii) optimal penalized variable effort policies, penalized versions based on including an artificial running energy cost on the effort; (iii) stepwise policies, staircase versions where the harvesting effort is determined at the beginning of each year (or of each biennium) and kept constant throughout that year (or biennium); (iv) constant harvesting effort sustainable policy, based on constant effort. They have different properties, so it is also worth looking at combinations of such policies and studying the single and cross-effects of the amount of penalization, the absence or presence and type of steps, and the restraints on minimum and maximum allowed efforts. Using data based on a real harvested population and considering a logistic growth model, we perform such a comparison study of pure and mixed policies in terms of profit, applicability, and other relevant properties. We end up answering the question: is the optimal enemy of the good?CEMAPRE/REM; FCT - Project UIDB/05069/2020; CIMA; FCT - Project UID/04674/202

Fisheries management in random environments: Comparison of harvesting policies for the logistic model

We describe the growth dynamics of a harvested fish population in a random environment using a stochastic differential equation logistic model, where the harvest term depends on a constant or a variable fishing effort. We consider revenues to be proportional to the yield and costs to be quadratic in terms of effort. We compare the optimal expected profit obtained with two types of harvesting policies, one based on variable effort, which is inapplicable, and the other based on a constant effort, which is applicable and sustainable. We answer two new questions: (a) What is the constant effort that optimizes the expected profit per unit time? (b) How do the two policies compare in terms of performance? We show that, in a realistic situation, there is only a slight reduction in profit when choosing the applicable constant effort policy instead of the inapplicable policy with variable effort

Lanthanide-based thermometers: At the cutting-edge of luminescence thermometry

Present technological demands in disparate areas, such as micro and nanofluidics, micro and nanoelectronics, photonics and biomedicine, among others, have reached to a development such that conventional contact thermal probes are not accomplished to perform accurate measurements with submicrometric spatial resolution. The development of novel non-contact thermal probes is, then, mandatory, contributing for an expansionary epoch of luminescence thermometry. Luminescence thermometry based on trivalent lanthanide ions becomes very popular since 2010 due to the unique versatility, stability and narrow emission band profiles of the ions that cover the entire electromagnetic spectrum with relatively high emission quantum yields. Here we give a perspective overview on the field since the beginnings in the 1950’s until the most recent cutting-edge examples. The current movement towards the technique usage as a new tool for thermal imaging, early tumor detection and as a tool for unveil properties of the thermometers themselves or of their local neighborhoods is also summarizedpublishe

A literature review on cardiovascular risk in human immunodeficiency virus-infected patients: implications for clinical management

AbstractIntroductionIn recent years, there has been growing concern about an increasing rate of cardiovascular diseases in human immunodeficiency virus-infected patients, which could be associated with side effects of highly active antiretroviral therapy. It is likely that the metabolic disorders related to anti-human immunodeficiency virus treatment will eventually translate into a increased cardiovascular risk in patients submitted to such regimens.ObjectiveTo evaluate if human immunodeficiency virus-infected patients receiving highly active antiretroviral therapy are at higher risk of cardiovascular diseases than human immunodeficiency virus infected patients not receiving highly active antiretroviral therapy, or the general population.Research design and methodsWe conducted a computer-based search in representative databases, and also performed manual tracking of citations in selected articles.ResultThe available evidence suggests an excess risk of cardiovascular events in human immunodeficiency virus-infected persons compared to non-human immunodeficiency virus infected individuals. The use of highly active antiretroviral therapy is associated with increased levels of total cholesterol, triglycerides, low-density lipoprotein and morphological signs of cardiovascular diseases. Some evidence suggested that human immunodeficiency virus-infected individuals on highly active antiretroviral therapy regimens are at increased risk of dyslipidemia, ischemic heart disease, and myocardial infarction, particularly if the highly active antiretroviral therapy regimen contains a protease inhibitor.ConclusionPhysicians must weigh the cardiovascular risk against potential benefits when prescribing highly active antiretroviral therapy. Careful cardiac screening is warranted for patients who are being evaluated for, or who are receiving highly active antiretroviral therapy regimens, particularly for those with known underlying cardiovascular risk factors. A better understanding of the molecular mechanisms responsible for increased risk of cardiovascular diseases in human immunodeficiency virus-infected patients will lead to the discovery of new drugs that will reduce cardiovascular risk in human immunodeficiency virus-infected patients receiving highly active antiretroviral therapy

Thermal enhancement of upconversion emission in nanocrystals: a comprehensive summary

Luminescence thermal stability is a major figure of merit of lanthanide-doped nanoparticles playing an essential role in determining their potential applications in advanced optics. Unfortunately, considering the intensification of multiple electron-vibration interactions as temperature increases, luminescence thermal quenching of lanthanide-doped materials is generally considered to be inevitable. Recently, the emergence of thermally enhanced upconversion luminescence in lanthanide-doped nanoparticles seemed to challenge this stereotype, and the research on this topic rapidly aroused wide attention. While considerable efforts have been made to explore the origin of this phenomenon, the key mechanism of luminescence enhancement is still under debate. Here, to sort out the context of this intriguing finding, the reported results on this exciting topic are reviewed, and the corresponding enhancement mechanisms as proposed by different researchers are summarized. Detailed analyses are provided to evaluate the contribution of the most believed ‘‘surface-attached moisture desorption’’ process on the overall luminescence enhancement of lanthanide-doped nanoparticles at elevated temperatures. The impacts of other surface-related processes and shell passivation on the luminescence behaviour of the lanthanide-doped materials are also elaborated. Lack of standardization in the reported data and the absence of important experimental information, which greatly hinders the cross-checking and reanalysis of the results, is emphasized as well. On the foundation of these discussions, it is realized that the thermal-induced luminescence enhancement is a form of recovery process against the strong luminescence quenching in the system, and the enhancement degree is closely associated with the extent of luminescence loss induced by various quenching effects beforehand.publishe

Impacto das políticas educativas e curriculares na construção das práticas inclusivas

Esta comunicação resulta de um trabalho de investigação desenvolvido em torno de três eixos – saberes básicos, inclusão educativa e diferenciação curricular – que têm vindo a ter uma visibilidade crescente tanto ao nível dos discursos educativos, como das políticas educativas e curriculares para o ensino básico. É imprescindível atender à diversidade, uma realidade cada vez mais comum no interior das salas de aulas, considerando-a não como um obstáculo mas como uma fonte enriquecedora do processo educativo, bem como à necessidade de transformar a escola num espaço de inclusão, para que cada aluno possa munir-se de um conjunto de saberes básicos imprescindíveis à sua integração e participação na sociedade. Neste sentido, importa perceber se os professores estão a conseguir uma efectiva flexibilização e diferenciação curriculares nas escolas ou se, pelo contrário, continuam entrincheirados entre rotinas securizantes, adiando a possibilidade de edificar uma verdadeira escola inclusiva. Partindo desta problemática, este projecto de investigação visou, entre outros aspectos compreender o impacto das políticas educativas e curriculares em termos de práticas inclusivas. Para o efeito, recorremos a uma estratégia metodológica de investigação que incluiu a aplicação de um questionário aos docentes do 1.º Ciclo do Ensino Básico e, posteriormente, a realização de entrevistas, a análise documental e a observação de aulas em duas situações específicas, configurando dois estudos de caso. Como principais conclusões podemos destacar que os dados confirmam e reforçam: (i) a ideia de que as questões curriculares são múltiplas, complexas e colocam-se a diferentes níveis, ou seja, desde o contexto em que o currículo é prescrito até ao contexto em que ele é efectivamente concretizado; e (ii) a recontextualização do currículo constitui um importante desafio tanto ao nível das estruturas como dos instrumentos de gestão curricular das escolas.This communication results from a research work developed in three areas - basic knowledge, educational inclusion and the curriculum differentiation - which have gained visibility both in the educational discourse, such as educational policies and curriculum for basic education. It is absolutely necessary to take into account the diversity, not as an obstacle but as a rich resource towards the educational process. It is relevant to understand if teachers are able to make a real flexibility and a correct curriculum differentiation in their schools or on the opposite are still attached to traditional routines, postponing the possibility to build a real inclusive school. This research had the following general aim: to understand the educational and curriculum policies’ impact considering the inclusive best practices. In this research we adopted a methodology which includes first the questionnaires for the teachers of the 1st cycle, second interviews, and then documentary analysis and finally the observation of two studies cases. The main conclusions allow to confirm and reinforce the obtained data that: (i) the idea that curriculum questions are multiple and very complex and are put up at different level, since the moment the curriculum is established till the moment it is performed. (ii) the reestablishment of the curriculum is an important challenge both at structural level and curriculum schools management tools

Comparison of different antibiotic protocols for asymptomatic bacteriuria in patients with neurogenic bladder treated with botulinum toxin A

AbstractIntravesical botulinum toxin A (BoNTA) injection has been widely used for the treatment of detrusor overactivity in patients with neurogenic bladder due to spinal cord injury who do not respond to conventional treatment. There is no consensus about antibiotic prophylaxis for this procedure. We conducted a retrospective analysis of medical records of adult patients with spinal cord injury who underwent detrusor BoNTA injection between January of 2007 and December of 2013 in a rehabilitation hospital. Occurrence of symptomatic urinary tract infection (UTI) was assessed in 3 groups in accordance with their use of antibiotics (prophylactic dosage, 3 days, more than 3 days) for the treatment of asymptomatic bacteriuria. All patients were performing self or assisted clean intermittent bladder catheterization and underwent a rigid cystoscopy, under general or regional anesthesia with sedation, and the drug used was Botox®. A total of 616 procedures were performed during the study period. There were 11 identified cases of UTI (1.8%) with a trend to a higher rate in the group that used antibiotics for longer time. This report shows that a single dose of antibiotics before the detrusor BoNTA injection is enough to prevent UTI. Randomized clinical trial should be conducted for definitive conclusions

The environmental aspects in the farmer's decision processv : a case study of Rural Taquara Nucleus

A pesquisa foi realizada em uma amostra de 75 produtores rurais utilizando-se questionário do tipo estruturado/semi-aberto. Verificou-se que o produtor rural decide, sob a luz do modelo econômico vigente, fundamentando suas decisões em elementos voltados à priorização de resultados econômicos, ou seja, a maximização do lucro. Neste sentido, seu processo decisório é conduzido na lógica da obtenção de maior volume de produção ao menor custo, fazendo uso de sua experiência e tradição, da tecnologia disponível e da assistência técnica, atento às condições do clima, à obtenção de um produto de qualidade e às sinalizações do mercado, em especial às relacionadas ao preço. Os aspectos ambientais só são contemplados, de forma prioritária, quando participam ou interferem de forma direta nos resultados econômicos da atividade; caso contrário, o equacionamento de suas questões se resumirá à simples utilização de algumas práticas e procedimentos específicos, considerados suficientes à solução do problema. A incorporação da dimensão ambiental ao processo decisório do produtor rural deve considerar, além da lógica de suas decisões, o papel do Estado como agente indutor de mudanças. A pesquisa foi realizada em uma amostra de 75 produtores rurais utilizando-se questionário do tipo estruturado/semi-aberto. Verificou-se que o produtor rural decide, sob a luz do modelo econômico vigente, fundamentando suas decisões em elementos voltados à priorização de resultados econômicos, ou seja, a maximização do lucro. Neste sentido, seu processo decisório é conduzido na lógica da obtenção de maior volume de produção ao menor custo, fazendo uso de sua experiência e tradição, da tecnologia disponível e da assistência técnica, atento às condições do clima, à obtenção de um produto de qualidade e às sinalizações do mercado, em especial às relacionadas ao preço. Os aspectos ambientais só são contemplados, de forma prioritária, quando participam ou interferem de forma direta nos resultados econômicos da atividade; caso contrário, o equacionamento de suas questões se resumirá à simples utilização de algumas práticas e procedimentos específicos, considerados suficientes à solução do problema. A incorporação da dimensão ambiental ao processo decisório do produtor rural deve considerar, além da lógica de suas decisões, o papel do Estado como agente indutor de mudanças. _______________________________________________________________________________ ABSTRACTThe research was accomplished in a sample of 75 farmers with the application of an open structured questionnaire. It was verified that farmers decide, under the actual economic model, make their decisions focused on the economic results, that is to say, the maximization of profit. In this sense, their decision is made by the logic of obtaining a larger production at the smallest cost making use of available technology and technical assistance, with regard to climatic conditions, obtaining a good quality product, observing market demands, mainly those related to price. The environmental aspects are only observed with priority when they participate or interfere in a direct way in the economic results, otherwise, the actions are summarised to simple practices and procedures considered enough by farmers to solve the problems. The integralization of environmental aspects in the farmers' decision process besides the logic of their decision must consider the role of State as a promoter of changes

Usando a Luz para Medir Temperatura

As exigências tecnológicas atuais em micro e nanoeletrónica, fotónica, micro e nanofluídica e biomedicina, entre outras áreas, atingiram um ponto em que a utilização de termómetros convencionais de contacto é incapaz de efetuar medições com resolução espacial na escala submicrométrica. O desenvolvimento de novas sondas térmicas de monitorização remota é, então, inevitável, o que tem contribuindo para a época expansionista da termometria de luminescência que estamos a atravessar. Em particular, a termometria de luminescência baseada em iões lantanídeos (trivalentes) tornou -se muito popular desde 2010 devido às características intrínsecas destes iões, onde se destacam a versatilidade e estabilidade da sua emissão de luz cobrindo todo o espectro eletromagnético com rendimentos quânticos relativamente elevados. Neste artigo, apresentamos uma visão geral do campo desde os seus primórdios na década de 1950 até aos desenvolvimentos mais recentes. O movimento atual para a utilização da técnica como ferramenta para a imagem térmica, deteção precoce de tumores e como ferramenta para desvendar propriedades dos próprios termómetros ou do seu ambiente local é, também, resumidamente discutido.info:eu-repo/semantics/publishedVersio