Evaluación niveles de iluminación en interiores y cálculo para instalaciones de alumbrado/Evaluation of interior lighting levels and calculation for lighting facilities

Siendo la iluminación una forma de energía, es uno de los agentes agresivos de tipo físico que inciden sobre el trabajador, pudiendo causar daños en su salud cuando esté fuera del rango tolerable. La presente investigación tiene como objetivo evaluar el nivel de iluminación de los trabajadores de la construcción dentro del área petrolera en el Oriente Ecuatoriano, mientras realizan sus actividades en oficinas. Se contempló la evaluación higiénica del riesgo físico de la Norma Oficial Mexicana, en cuanto a las condiciones de iluminación en los centros de trabajo, luego el valor obtenido se compara con lo establecido en el decreto ejecutivo 2393. Para el cálculo de iluminación general en instalaciones interiores, se utilizó el método denominado Sistema General o del Factor de utilización, que proporciona una iluminancia media. El resultado promedio de la evaluación dio 458,22 luxes, que se encuentra por debajo del nivel mínimo permisible de 500 luxes para trabajos de diseño, revisión y corrección de planos, de modo que es necesaria la intervención mediante un programa de prevención de riesgos físicos por iluminación, para minimizar el riesgo actual y prevenir futuras lesiones oculares o enfermedades profesionales que puedan presentarse al mantener las condiciones actuales de trabajo. Being the lighting a form of energy, it is one of the aggressive agents of physical type that affect the worker, being able to cause damages in his health when he is outside the tolerable range. The objective of this research is to evaluate the level of lighting of construction workers within the oil area in the Ecuadorian Oriente, while carrying out their activities in offices. The hygienic evaluation of the physical risk of the Official Mexican Standard was contemplated, in terms of lighting conditions in the work centers, then the value obtained is compared with that established in executive decree 2393. For the calculation of general lighting in facilities interiors, the method called General System or the Utilization Factor was used, which provides an average illuminance. The average result of the evaluation gave 458.22 luxes, which is below the minimum permissible level of 500 luxes for design work, review and correction of plans, so that intervention is necessary through a program of prevention of physical risks by lighting to minimize the current risk and prevent future eye injuries or occupational diseases that may occur when maintaining current work conditions. Palabras clave: NOM-025, evaluación, iluminación, instalaciones alumbrado. Keywords: NOM-025, evaluation, lighting, installations lighting

Chemists’ knowledge object. Formulation, modification and abandonment of iconic model

This article presents an analysis of different perspectives in regards to chemistry scientific statute. The category of scientific model was considered to characterize the proposal and development of technological-iconic model. It was necessary to have a look at the time in which the introduction of analogical and symbolic models was indispensable to modify the initial model. It also established the way in which the technological-iconic model can be a didactic foundation to lead secondary students towards Chemistry as one of the natural sciences

Abundance and diversity of Heteropteran species in portuguese olive groves

The olive tree canopy is a habitat for phytophagous and predaceous Heteropteran specimens whose biodiversity is important to be characterized. The aim of this world was to study the abundance and diversity of Heteropteran specimens in Portuguese olive groves with different plant protection systems (conventional. integrated protection and organic farming groves). Therefore, data were obtained in olive groves located in the main olive Portuguese regions (Alto Alentejo and Trás-os-Montes). Sampling occurred in 1999, 2000, 2002 and 2003 and samples were obtained through the beating technique, on a weekly or fortnight basis from March to November of each year. The captured heteropteran specimens were identified to family level and, when possible, to genera or species level. Experimental results showed that specimens belonged to six families that were, for order of importance: Anthocoridae, Miridae. Lygaeidae, Tingidae, Penlalomidae and Nabidae. Beneficial predaceous specimens like AntiJocoris sp. and Deraeocoris lutenscens (Schilling, 1837) were the most abundant of the Anthocoridae and Miridae families, respectively. These families were more abundant from the beginning to the middle of June which coincided with the antophagou5 larval stage of the olive moth, Prays oleae (Bernard)

El contexto histórico didáctico de la institucionalización de la Química como ciencia

Se dan a conocer algunas conclusiones derivadas de revisiones históricas, sobre cómo la química y la labor de los químicos fueron constituyendo paulatinamente esta ciencia, logrando su institucionalización y el reconocimiento social de su actividad de producción de conocimiento. Se entiende aquí la institucionalización en los términos que han establecido los historiadores sociales de las ciencias, destacándose la poca atención que han prestado a los procesos didácticos para este cometido. El punto de partida que se adopta, es el de que la conversión de las ciencias en ciencia escolar contribuyó significativamente a dicha institucionalización. Se examina el papel de los textos de enseñanza que formularon discípulos e incidieron en la creación y consolidación de una comunidad científica sin olvidar por supuesto, el rol cumplido por las revistas especializadas en química y la industrialización.Palabras clave: Historia social de las ciencias; institucionalización; textos de enseñanza; revistas especializadas.The didactic historical context of the institutionalization of Chemistry like scienceThey occur to know some conclusions derived from historical revisions, on like the chemistry and the work of chemistries that were constituting this science gradually and obtaining the institutionalization of her and del social recognition of its activity of knowledge production. The institutionalization is understood here, in the terms that have established the social historians of sciences, standing out the little attention that has rendered to the didactic processes for this assignment. The departure point that is adopted, is the one of which the conversion of sciences in scholastic science contributed significantly to this institutionalization. It is examined the paper of the education texts that formulated disciples and affected the creation and consolidation of a scientific community without forgetting of course, the roll fulfilled by the magazines specialized in chemistry and industrialization.Keywords: Social history of sciences; institutionalization; texts of education

Confusing the extragalactic neutrino flux limit with a neutrino propagation limit

We study the possible suppression of the extragalactic neutrino flux due to a nonstandard interaction during its propagation. In particular, we study neutrino interaction with an ultra-light scalar field dark matter. It is shown that the extragalactic neutrino flux may be suppressed by such an interaction, leading to a new mechanism to reduce the ultra-high energy neutrino flux. We study both the cases of non-self-conjugate as well as self-conjugate dark matter. In the first case, the suppression is independent of the neutrino and dark matter masses. We conclude that care must be taken when explaining limits on the neutrino flux through source acceleration mechanisms only, since there could be other mechanisms for the reduction of the neutrino flux.Comment: 15 pages, 4 figures. Important changes implemented. Abstract modified. Conclusions remain. To be published in JCA

Instalação de um ensaio de produção intensiva de biomassa lenhosa para energia

No âmbito de um projecto de investigação tendo como propósito o desenvolvimento de sistemas sustentáveis de produção de biomassa lenhosa para energia, foi instalado em Bragança, em 2008, um ensaio de produção intensiva de biomassa lenhosa com base em culturas de curta rotação. Este ensaio tem como objectivos específicos a avaliação dos efeitos de factores como material vegetal, densidade de plantação, rega e fertilização no crescimento e produção de biomassa lenhosa. Nesta comunicação descrevemos a instalação do ensaio relativamente ao desenho experimental seguido, estrutura interna das parcelas de estudo, material vegetal utilizado, operações de preparação do solo e de plantação e ainda gestão da cultura com respeito a fertilização, rega e protecção. Avaliamos também a sobrevivência das plantas no final da primeira estação de crescimento, bem como apresentamos os custos gerais associados à instalação. A apresentação deste trabalho permite partilhar com a comunidade científica e técnica nacional a experiência da instalação deste tipo de culturas, muito recentes no nosso país, e dessa forma contribuir para a definição de processos ajustados e eficientes de instalação e gestão de culturas lenhosas para produção de biomassa para energia em Portugal

Dirofilaria immitis parasite infection in cats: first case reported in the Legal Amazon region, Brazil - case report

ABSTRACT A case of infection with Dirofilaria immitis in a cat is reported here with clinical signs of apathy, anorexia, dyspnea, polypnea, slight dehydration and pale mucus membranes. The radiographic examination showed cardiomegaly, lobar arteries dilation of the cranial lobes and tortuosity, enlargement of the caudal lobar arteries. In the right lobe of the lung parenchyma, interstitial pulmonary opacification tending to alveolar opacification was seen. The clinical signs, the movements, and the morphology of the microfilariae in the direct examination of fresh blood, peripheral blood smear and Knott’s modified test supported the diagnosis. We alert to the need for clinicians to consider feline heartworm diseases as a differential diagnosis in endemic areas when cats show respiratory signs

Anomalous heavy-fermion and ordered states in the filled skutterudite PrFe4P12

Specific heat and magnetization measurements have been performed on high-quality single crystals of filled-skutterudite PrFe_4P_{12} in order to study the high-field heavy-fermion state (HFS) and low-field ordered state (ODS). From a broad hump observed in C/T vs T in HFS for magnetic fields applied along the direction, the Kondo temperature of ~ 9 K and the existence of ferromagnetic Pr-Pr interactions are deduced. The {141}-Pr nuclear Schottky contribution, which works as a highly-sensitive on-site probe for the Pr magnetic moment, sets an upper bound for the ordered moment as ~ 0.03 \mu_B/Pr-ion. This fact strongly indicates that the primary order parameter in the ODS is nonmagnetic and most probably of quadrupolar origin, combined with other experimental facts. Significantly suppressed heavy-fermion behavior in the ODS suggests a possibility that the quadrupolar degrees of freedom is essential for the heavy quasiparticle band formation in the HFS. Possible crystalline-electric-field level schemes estimated from the anisotropy in the magnetization are consistent with this conjecture.Comment: 7 pages and 7 figures. Accepted for publication in Phys. Rev.

Quantum Griffiths effects and smeared phase transitions in metals: theory and experiment

In this paper, we review theoretical and experimental research on rare region effects at quantum phase transitions in disordered itinerant electron systems. After summarizing a few basic concepts about phase transitions in the presence of quenched randomness, we introduce the idea of rare regions and discuss their importance. We then analyze in detail the different phenomena that can arise at magnetic quantum phase transitions in disordered metals, including quantum Griffiths singularities, smeared phase transitions, and cluster-glass formation. For each scenario, we discuss the resulting phase diagram and summarize the behavior of various observables. We then review several recent experiments that provide examples of these rare region phenomena. We conclude by discussing limitations of current approaches and open questions.Comment: 31 pages, 7 eps figures included, v2: discussion of the dissipative Ising chain fixed, references added, v3: final version as publishe