MV producers and consumers agents characterization with DSM techniques

This paper consist in the establishment of a Virtual Producer/Consumer Agent (VPCA) in order to optimize the integrated management of distributed energy resources and to improve and control Demand Side Management DSM) and its aggregated loads. The paper presents the VPCA architecture and the proposed function-based organization to be used in order to coordinate the several generation technologies, the different load types and storage systems. This VPCA organization uses a frame work based on data mining techniques to characterize the costumers. The paper includes results of several experimental tests cases, using real data and taking into account electricity generation resources as well as consumption data.

Real-time scheduling of parallel tasks in the Linux Kernel

This paper proposes a global multiprocessor scheduling algorithm for the Linux kernel that combines the global EDF scheduler with a priority-aware work-stealing load balancing scheme, enabling parallel real-time tasks to be executed on more than one processor at a given time instant. We state that some priority inversion may actually be acceptable, provided it helps reduce contention, communication, synchronisation and coordination between parallel threads, while still guaranteeing the expected system’s predictability. Experimental results demonstrate the low scheduling overhead of the proposed approach comparatively to an existing real-time deadline-oriented scheduling class for the Linux kernel.

Offshore wind turbine simulation: multibody drive train. Bacl-to-back NPC (Neutral Point Clamped) converters: Fractional-order control

This paper is on offshore wind energy conversion systems installed on the deep water and equipped with back-to-back neutral point clamped full-power converter, permanent magnet synchronous generator with an AC link. The model for the drive train is a five-mass model which incorporates the dynamic of the structure and the tower in order to emulate the effect of the moving surface. A three-level converter and a four-level converter are the two options with a fractional-order control strategy considered to equip the conversion system. Simulation studies are carried out to assess the quality of the energy injected into the electric grid. Finally, conclusions are presented. (C) 2014 Elsevier Ltd. All rights reserved.

Stress relacionado com o trabalho e burnout em técnicos de radiologia

RESUMO - O fenómeno stress relacionado com o trabalho é um tema atual, bastante debatido e alvo de diversas investigações. No entanto, os estudos portugueses sobre o stress relacionado com o trabalho em profissionais de saúde não são muito frequentes, apesar de desempenharem uma atividade considerada de alto risco em termos de stress. O síndrome de burnout é a consequência de prolongados níveis de stress relacionado com o trabalho e compreende três dimensões: exaustão emocional (EE), despersonalização (DSP) e realização pessoal (RP). O presente estudo demonstra-se como não experimental, descritivo e transversal que pretende contribuir para uma melhor compreensão do stress relacionado com o trabalho e burnout em técnicos de radiologia. Estudaram-se 73 técnicos de radiologia do Centro Hospitalar de Lisboa Central. 76,4% da população em estudo é do sexo feminino, 58,9% tem idades compreendidas entre os 41 e 60 anos, 53,4% dos profissionais são casados e 56,1% tem entre 1 e 20 anos de serviço como técnico de radiologia nos locais em estudo. Foram utilizados três questionários, um sócio-demográfico, o questionário Perceived Stress Scale (versão portuguesa do Instituto de Prevenção do Stress e Saúde Ocupacional) e o questionário Maslach Burnout Inventory (versão portuguesa traduzida pela Drª Alexandra Pinto. Verifica-se que 50,7% dos profissionais em estudo percecionam o seu nível de stress relacionado com o trabalho como elevado. Na análise da perceção do stress relacionado com o trabalho, foram os homens que surgiram com um nível mais elevado, assim como os profissionais dos 20 aos 40 anos, os solteiros e aqueles com um tempo de serviço entre 1 e 20 anos. Em relação ao burnout verificamos que 66,2% da população em estudo apresenta nível médio a elevado de EE, 57,9% de DSP e 66,2% de RP. Podemos verificar que são as mulheres que surgem com valores mais elevados de EE e RP, enquanto os homens apresentam valores mais elevados na dimensão DSP. Os mais novos (20 a 40 anos) e os solteiros apresentam nível médio a elevado de EE e DSP, enquanto os mais velhos (41 aos 60 anos) e os casados demonstram níveis mais elevados de RP. Estes dados demonstram um nível médio a elevado de burnout vivenciado pelos técnicos de radiologia dos hospitais em estudo.

Diseño e implantación de un sistema SCADA para una planta de producción y envasado de líquidos

Este proyecto consiste en la implantación de un sistema SCADA en una planta piloto de fabricación y envasado de líquidos. En este documento se muestra toda la información que ha sido necesaria para realizar el sistema de automatización en los tres niveles propios de un SCADA: nivel de campo, nivel de control y nivel de supervisión. El trabajo de campo ha sido, típicamente de revisión, puesto que el Departament de Telecomunicació i d’Enginyeria de Sistemes ya poseía la planta totalmente equipada, mientras que el sistema de control y el sistema de supervisión se han implantado totalmente.

A Political Agency Model of Coattail Voting

In this paper, I provide a formal justi…cation for a well-established coattail effect, when a popular candidate at one branch of government attracts votes to candidates from the same political party for other branches of government. A political agency frame- work with moral hazard is applied to analyze coattails in simultaneous presidential and congressional elections. I show that coattail voting is a natural outcome of the optimal reelection scheme adopted by a representative voter to motivate politicians' efforts in a retrospective voting environment. I assume that an office-motivated politician (executive or congressman) prefers her counterpart to be affiliated with the same political party. This correlation of incentives leads the voter to adopt a joint performance evaluation rule, which is conditioned on the politicians belonging to the same party or different parties. The two-sided coattail effects then arise. On the one hand, the executive's suc- cess/failure props up/drags down her partisan ally in congressional election, which implies presidential coattails. On the other hand, the executive's reelection itself is affected by the congressman's performance, which results in reverse coattails. JEL classi…fication: D72, D86. Keywords: Coattail voting; Presidential coattails; Reverse coattails; Simultaneous elections; Political Agency; Retrospective voting.

Multilevel oblique corpectomy for cervical spondylotic myelopathy preserves segmental motion.

PURPOSE: To document the neurological outcome, spinal alignment and segmental range of movement after oblique cervical corpectomy (OCC) for cervical compressive myelopathy. METHODS: This retrospective study included 109 patients--93 with cervical spondylotic myelopathy and 16 with ossified posterior longitudinal ligament in whom spinal curvature and range of segmental movements were assessed on neutral and dynamic cervical radiographs. Neurological function was measured by Nurick's grade and modified Japanese Orthopedic Association (JOA) scores. Eighty-eight patients (81%) underwent either a single- or two-level corpectomy; the remaining (19%) undergoing three- or four-level corpectomies. The average duration of follow-up was 30.52 months. RESULTS: The Nurick's grade and the JOA scores showed statistically significant improvements after surgery (p < 0.001). The mean postoperative segmental angle in the neutral position straightened by 4.7 ± 6.5°. The residual segmental range of movement for a single-level corpectomy was 16.7° (59.7% of the preoperative value), for two-level corpectomy it was 20.0° (67.2%) and for three-level corpectomies it was 22.9° (74.3%). 63% of patients with lordotic spines continued to have lordosis postoperatively while only one became kyphotic without clinical worsening. Four patients with preoperative kyphotic spines showed no change in spine curvature. None developed spinal instability. CONCLUSIONS: The OCC preserves segmental motion in the short-term, however, the tendency towards straightening of the spine, albeit without clinical worsening, warrants serial follow-up imaging to determine whether this motion preservation is long lasting.

Multi-stage oligopoly models with nested logit demand structures: A simplifying approach

Solving multi-stage oligopoly models by backward induction can easily become a com- plex task when rms are multi-product and demands are derived from a nested logit frame- work. This paper shows that under the assumption that within-segment rm shares are equal across segments, the analytical expression for equilibrium pro ts can be substantially simpli ed. The size of the error arising when this condition does not hold perfectly is also computed. Through numerical examples, it is shown that the error is rather small in general. Therefore, using this assumption allows to gain analytical tractability in a class of models that has been used to approach relevant policy questions, such as for example rm entry in an industry or the relation between competition and location. The simplifying approach proposed in this paper is aimed at helping improving these type of models for reaching more accurate recommendations.

Metabolic equivalent: one size does not fit all.

The metabolic equivalent (MET) is a widely used physiological concept that represents a simple procedure for expressing energy cost of physical activities as multiples of resting metabolic rate (RMR). The value equating 1 MET (3.5 ml O2 x kg(-1) x min(-1) or 1 kcal x kg(-1) x h(-1)) was first derived from the resting O2 consumption (VO2) of one person, a 70-kg, 40-yr-old man. Given the extensive use of MET levels to quantify physical activity level or work output, we investigated the adequacy of this scientific convention. Subjects consisted of 642 women and 127 men, 18-74 yr of age, 35-186 kg in weight, who were weight stable and healthy, albeit obese in some cases. RMR was measured by indirect calorimetry using a ventilated hood system, and the energy cost of walking on a treadmill at 5.6 km/h was measured in a subsample of 49 men and 49 women (26-45 kg/m2; 29-47 yr). Average VO2 and energy cost corresponding with rest (2.6 +/- 0.4 ml O2 x kg(-1) x min(-1) and 0.84 +/- 0.16 kcal x kg(-1) x h(-1), respectively) were significantly lower than the commonly accepted 1-MET values of 3.5 ml O2 x kg(-1) x min(-1) and 1 kcal x kg(-1) x h(-1), respectively. Body composition (fat mass and fat-free mass) accounted for 62% of the variance in resting VO2 compared with age, which accounted for only 14%. For a large heterogeneous sample, the 1-MET value of 3.5 ml O2 x kg(-1) x min(-1) overestimates the actual resting VO2 value on average by 35%, and the 1-MET of 1 kcal/h overestimates resting energy expenditure by 20%. Using measured or predicted RMR (ml O2 x kg(-1) x min(-1) or kcal x kg(-1) x h(-1)) as a correction factor can appropriately adjust for individual differences when estimating the energy cost of moderate intensity walking (5.6 km/h).

Contribuição dos factores motivacionais para a satisfação no trabalho

A motivação é vista, desde meados do Século XX, como o principal factor de satisfação no trabalho, de aumento da produtividade e de melhoria da qualidade dos produtos e serviços. Na conclusão de um curso conducente ao Mestrado em Gestão Global, interessou-nos abordar o valor humano da organização, cujo componente importante é o nível de satisfação das pessoas no trabalho, obtido da avaliação a um leque de variáveis independentes, relacionadas com duas coisas – o conteúdo do trabalho e o contexto do trabalho. O objectivo da presente dissertação é identificar em que medida as variáveis do meio envolvente do trabalho contribui para a satisfação no trabalho. Inspirados na Teoria dos dois Factores (Herzberg, 1959 e 1982) e na Teoria da Avaliação Cognitiva (Deci, 1971), pretendemos justapor a satisfação das pessoas à diferentes variáveis particulares que formam dois subsistemas – o intrínseco ou motivador, que inclui a aprendizagem, as emoções, o trabalho em si, a realização e o reconhecimento; e o extrínseco ou higiénico, que inclui o salário, a supervisão e as condições físicas. Além de uma incursão à literatura especializada, realizamos dois inquéritos em empresas cabo-verdianas, um em Outubro de 2003 e outro em Outubro de 2007, que nos permitiram determinar índices específicos e gerais de satisfação no trabalho, fazer correlações e análises comparativas. Concluímos que as pessoas estão razoavelmente satisfeitas no trabalho, dão mais ênfase aos factores do conteúdo que aos factores do contexto do trabalho, mas a fonte de satisfação varia de categoria por categoria. Work motivation is viewed, since middle of the 20th Century, as a main factor of job satisfaction, also for increasing of productivity and quality of goods and services. By the ending of a Master’s Programme in Global Management, we was moved by a great interest to research and report about the organization human values, important component of which is the people’s satisfaction level in work conditions, obtained through an evaluation of a great number of independent variables, related to two items – work content and work context. The main objective of the present dissertation is to identify in which measure the job environmental variables contribute to work satisfaction. Inspired into the Two Factors Theory (Herzberg, 1959, 1982) and into The Cognitive Evaluation Theory (Deci, 1971), we intent to relate people satisfaction to different particular variables, which perform two subsystems – intrinsic or motivator, that includes learning, emotions, work itself, achievement and recognition and; extrinsic or hygienic, that includes salary, supervision and work physical conditions. Besides a specialized literature review, we took up two separated inquiries within capeverdian companies, the first conducted in October, 2003, and the second in October, 2007, which allowed specifics and general job satisfaction indexes, correlations and comparative analysis. We concluded that people are fair satisfied on job, and give more emphasis on work content factors, than on work context factors, but the source of satisfaction is different category by category.

Spatial distribution of a spherical gall (Hymenoptera, Eulophidae) on Caryocar brasiliense (Caryocaraceae)

We obtained the first data on spatial distribution of a spherical galling insect (Hymenoptera, Eulophidae) at the Caryocar brasiliense Camb. (Caryocaraceae) tree level. This work was developed in two pastures in Montes Claros, Minas Gerais State, Brazil. The areas studied were: pasture 1 (in activity) and pasture 2 (abandoned pasture = savanna in recovery). We evaluated the distribution of spherical galls in: foliage orientation (slope), among leaves (border and interior of the tree crown), among leaflets (right, central, left), distal, median, and proximal as well as border, central area, and adjacent to the mid leaf vein of the leaflet, and difference between areas in 10 infested trees per area. The smaller number of spherical gall/leaflet was observed in pasture 1 than in pasture 2. More spherical galls were found on the northern in pasture 1, but in the pasture 2, the lower spherical galls were observed on the northeast than other slopes. The average number of spherical galls did not differ statistically among the three leaflets of C. brasiliense in pasture 2. However, in pasture 1, we observed highest number of spherical galls in the central leaflet. More spherical galls were found in the border than interior of the tree crown. The average number of spherical galls did not differ statistically among the longitudinal region on leaflet of C. brasiliense. The spherical gall insect preferred to colonize the leaf margin than the central portion or near mid vein on transversal regions on a leaflet.

Cyclododecane exposure in the field of conservation and restoration of art objects

PURPOSE: Recent work practices in the conservation and restoration involve the use of cyclododecane (CDD, CAS 294-62-2) to protect fragile artifacts during their handling or transportation. Little is known about its toxicity, and no previous exposure has been reported. A short field investigation was conducted to characterize the exposure conditions to both CDD vapors and aerosols.METHODS: Measurements were conducted in the laboratory of conservation and restoration of the archeological service in Bern (Switzerland). Three indoor and four outdoor typical work situations, either during brush or spray gun applications, were investigated. Measurements were performed on charcoal adsorbent tube and analyzed by a gas chromatograph equipped with a flame ionization detector.RESULTS: Measurements have been conducted during both brush and spray gun applications. Indoor exposures were of 0.75-15.5 mg/m(3), while outdoors exposures were 19.5-53.9 mg/m(3). Exposures appear to be extremely localized due to both physicochemical properties and application methods of the CDD. Vapor exposure increases dramatically with the confinement of the workplace.CONCLUSION: Preventive measures should be undertaken to limit as much as possible these exposures. Field work in confined areas (ditches, underground) is of particular concern. CDD-coated artifacts or materials should be stored in ventilated areas to avoid delayed exposures. [Authors]

Developmental and Environmental Regulation of Aquaporin Gene Expression across Populus Species: Divergence or Redundancy?

Aquaporins (AQPs) are membrane channels belonging to the major intrinsic proteins family and are known for their ability to facilitate water movement. While in Populus trichocarpa, AQP proteins form a large family encompassing fifty-five genes, most of the experimental work focused on a few genes or subfamilies. The current work was undertaken to develop a comprehensive picture of the whole AQP gene family in Populus species by delineating gene expression domain and distinguishing responsiveness to developmental and environmental cues. Since duplication events amplified the poplar AQP family, we addressed the question of expression redundancy between gene duplicates. On these purposes, we carried a meta-analysis of all publicly available Affymetrix experiments. Our in-silico strategy controlled for previously identified biases in cross-species transcriptomics, a necessary step for any comparative transcriptomics based on multispecies design chips. Three poplar AQPs were not supported by any expression data, even in a large collection of situations (abiotic and biotic constraints, temporal oscillations and mutants). The expression of 11 AQPs was never or poorly regulated whatever the wideness of their expression domain and their expression level. Our work highlighted that PtTIP1;4 was the most responsive gene of the AQP family. A high functional divergence between gene duplicates was detected across species and in response to tested cues, except for the root-expressed PtTIP2;3/PtTIP2;4 pair exhibiting 80% convergent responses. Our meta-analysis assessed key features of aquaporin expression which had remained hidden in single experiments, such as expression wideness, response specificity and genotype and environment interactions. By consolidating expression profiles using independent experimental series, we showed that the large expansion of AQP family in poplar was accompanied with a strong divergence of gene expression, even if some cases of functional redundancy could be suspected.

Clinical review: Update on neurally adjusted ventilatory assist - report of a round-table conference.

ABSTRACT: Conventional mechanical ventilators rely on pneumatic pressure and flow sensors and controllers to detect breaths. New modes of mechanical ventilation have been developed to better match the assistance delivered by the ventilator to the patient's needs. Among these modes, neurally adjusted ventilatory assist (NAVA) delivers a pressure that is directly proportional to the integral of the electrical activity of the diaphragm recorded continuously through an esophageal probe. In clinical settings, NAVA has been chiefly compared with pressure-support ventilation, one of the most popular modes used during the weaning phase, which delivers a constant pressure from breath to breath. Comparisons with proportional-assist ventilation, which has numerous similarities, are lacking. Because of the constant level of assistance, pressure-support ventilation reduces the natural variability of the breathing pattern and can be associated with asynchrony and/or overinflation. The ability of NAVA to circumvent these limitations has been addressed in clinical studies and is discussed in this report. Although the underlying concept is fascinating, several important questions regarding the clinical applications of NAVA remain unanswered. Among these questions, determining the optimal NAVA settings according to the patient's ventilatory needs and/or acceptable level of work of breathing is a key issue. In this report, based on an investigator-initiated round table, we review the most recent literature on this topic and discuss the theoretical advantages and disadvantages of NAVA compared with other modes, as well as the risks and limitations of NAVA.

Estudio de la accesibilidad de los documentos cientificos en soporte digital

Resumen: El artículo analiza los problemas de accesibilidad que actualmente presentan los artículos científicos en soporte digital. El estudio se centra en los aspectos de facilidad de uso del contenido de los documentos digitales según la forma en que se publiquen, sin entrar en el estudio de los distintos sistemas de recuperación. Se analizan los dos formatos más utilizados para la publicación de artículos científicos en soporte digital: HTML y PDF, estudiando el desempeño lector en relación a la presencia de sumarios o de tablas internas o vinculadas. El estudio se ha realizado con dos colectivos: 30 sujetos ciegos, usuarios de Jaws, contactados gracias a la mediación de la Fundación ONCE, y 30 sujetos no ciegos, profesores del Departamento de Biblioteconomía y Documentación de la Universidad de Barcelona. El estudio muestra que la localización de los datos contenidos en tablas se ve facilitada en documentos HTML por la inclusión de un sumario que vincule con la tabla, así como la inclusión de tablas completas en el cuerpo del documento HTML facilita la actividad lectora por parte de los usuarios ciegos. A nivel metodológico la presente investigación aporta dos novedades relevantes respecto a la literatura existente en los estudios de usabilidad con ciegos: estudia la usabilidad del formato PDF y es un test de usabilidad cuantitativo; este último hecho dificulta su comparación con la mayoría de artículos publicados. Abstract: This paper analyses the problems of accessibility posed by scientific articles published in digital format, focusing on the ease of use of their content with respect to the form in which they are published (irrespective of the recovery system). The two most widely used formats for the publication of scientific articles in digital format, HTML and PDF, are analysed, examining reader performance in relation to the presence of contents lists or internal or linked tables. The study involved two groups: 30 blind subjects, all JAWS users, contacted through the ONCE Foundation, and 30 sighted subjects, lecturers in the Department of Librarianship and Documentation of the University of Barcelona. The results shows the location of data in tables is easier in HTML documents through the inclusion of a contents list linked to these tables. Further, the inclusion of complete tables in the body of HTML document facilitates the reading activity of blind users. At the methodological level, this work reports two novelties with respect to the existing literature on usability by blind people: it examines the usability of the PDF format, and discusses a quantitative usability test. The latter hinders comparison with the majority of published articles.