Caracterización térmica de un edificio del centro bonaerense mediante mediciones y modelado analítico

Se presenta el análisis de mediciones continuas y sistemáticas de temperatura y humedad en puntos específicos del interior y las variables meteorológicas externas de un edificio público ubicado en la periferia de la ciudad de Tandil (Buenos Aires) cuya construcción es representativa de los estándares edilicios locales. La información obtenida es asociada mediante un modelo analítico que da cuenta de las contribuciones de la conductividad, radiación y convección debida al viento en la consideración de las propiedades térmicas del edificio. A partir de ellas, es posible estimar los coeficientes de la ecuación diferencial resultante que permite obtener la evolución de la temperatura interna para diferentes condiciones. El procedimiento es sencillo de realizar y da resultados útiles que pueden emplearse para corroborar la viabilidad de los materiales empleados en la construcción y el funcionamiento térmico del conjuntoFil: Muñoz Vásquez, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; ArgentinaFil: Marino, Beatriz Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; ArgentinaFil: Thomas, Luis Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentin

Development of a novel equine influenza virus live-attenuated vaccine

H3N8 equine influenza virus (EIV) is an important and significant respiratory pathogen of horses. EIV is enzootic in Europe and North America, mainly due to the suboptimal efficacy of current vaccines. We describe, for the first time, the generation of a temperature sensitive (ts) H3N8 EIV live-attenuated influenza vaccine (LAIV) using reverse-genetics approaches. Our EIV LAIV was attenuated (att) in vivo and able to induce, upon a single intranasal administration, protection against H3N8 EIV wild-type (WT) challenge in both a mouse model and the natural host, the horse. Notably, since our EIV LAIV was generated using reverse genetics, the vaccine can be easily updated against drifting or emerging strains of EIV using the safety backbone of our EIV LAIV as master donor virus (MDV). These results demonstrate the feasibility of implementing a novel EIV LAIV approach for the prevention and control of currently circulating H3N8 EIVs in horse populations

Correlation between velocity and backscatter distributions and zooplankton concentration in a modified estuary

Las señales del backscatter correspondientes a organismos planctónicos y sedimentos suspendidos son identificadas comparando la información proporcionada por sensores CTD + OBS y un ecosonda en el sector costero de un estuario modificado. Las mediciones se complementan con las distribuciones transversales de velocidad y backscatter proporcionadas por un ADCP y los perfiles de temperatura, salinidad y turbidez en estaciones fijas. El propósito es relacionar la agregación del material biológico con la hidrodinámica y morfología locales tanto cuando el estuario se encuentra naturalmente estratificado como cuando se produce el mezclado de las aguas debido, por ejemplo, a la ocurrencia de tormentas severas. La interpretación de los registros hidroacústicos muestra que el zooplancton tiende a concentrarse selectivamente en regiones de corriente débil y con escaso contenido de sedimentos suspendidos, lo cual no es sólo relevante desde un punto de vista práctico y físico sino biológico ya que estos organismos constituyen el primer eslabón de la cadena trófica acuáticaThe backscatter signals corresponding to planktonic organisms and suspended sediments are identified bycomparing CTD + OBS sensors and echosounder data in the coastal sector of a modified estuary. Themeasurements are complemented with transverse velocity and backscatter distributions obtained with an ADCPand profiles of temperature, salinity and turbidity in fixed stations. The purpose is to relate the aggregation ofbiological matter to the local hydrodynamics and morphology when the estuary is naturally stratified and whenthe mixing of waters occurs due to, for example, the occurrence of severe storms. The interpretation of hydroacousticrecords shows that zooplankton tends to accumulate selectively in regions with slow currents and scarcecontent of suspended sediments, which is not only important from practical and physical points of view but alsobiological, since these organisms are the first link in the aquatic food chain.Fil: Thomas, Luis Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; ArgentinaFil: Pereyra, Mariana Gisele. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; ArgentinaFil: Marino, Beatriz Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentin

Factors Associated with Marburg Hemorrhagic Fever:

Background. Reliable on-site polymerase chain reaction (PCR) testing for Marburg hemorrhagic fever (MHF) is not always available. Therefore, clinicians triage patients on the basis of presenting symptoms and contact history. Using patient data collected in Uige, Angola, in 2005, we assessed the sensitivity and specificity of these factors to evaluate the validity of World Health Organization (WHO)–recommended case definitions for MHF. Methods. Multivariable logistic regression was used to identify independent predictors of PCR confirmation of MHF. A data-derived algorithm was developed to obtain new MHF case definitions with improved sensitivity and specificity. Results. A MHF case definition comprising (1) an epidemiological link or (2) the combination of myalgia or arthralgia and any hemorrhage could potentially serve as an alternative to current case definitions. Our dataderived case definitions maintained the sensitivity and improved the specificity of current WHO-recommended case definitions. Conclusions. Continued efforts to improve clinical documentation during filovirus outbreaks would aid in the refinement of case definitions and facilitate outbreak control

Arrested dynamics of the dipolar hard-sphere model

We report the combined results of molecular dynamics simulations and theoretical calculations concerning various dynamical arrest transitions in a model system representing a dipolar fluid, namely, N (softcore) rigid spheres interacting through a truncated dipole-dipole potential. By exploring different regimes of concentration and temperature, we find three distinct scenarios for the slowing down of the dynamics of the translational and orientational degrees of freedom: At low ({$\eta$} = 0.2) and intermediate (${\eta}$ = 0.4) volume fractions, both dynamics are strongly coupled and become simultaneously arrested upon cooling. At high concentrations ({$\eta$} $\lt$ 0.6), the translational dynamics shows the features of an ordinary glass transition, either by compressing or cooling down the system, but with the orientations remaining ergodic, thus indicating the existence of partially arrested states. In this density regime, but at lower temperatures, the relaxation of the orientational dynamics also freezes. The physical scenario provided by the simulations is discussed and compared against results obtained with the self-consistent generalized Langevin equation theory, and both provide a consistent description of the dynamical arrest transitions in the system. Our results are summarized in an arrested states diagram which qualitatively organizes the simulation data and provides a generic picture of the glass transitions of a dipolar fluid

The network BiodiversityKnowledge in practice: insights from three trial assessments

In order to develop BiodiversityKnowledge, a Network of Knowledge working at the European science–policy interface for biodiversity and ecosystem services, we conducted three trial assessments. Their purpose was to test structure and processes of the knowledge synthesis function and to produce knowledge syntheses. The trial assessments covered conservation and management of kelp ecosystems, biological control of agricultural pests, and conservation and multifunctional management of floodplains. Following the BiodiversityKnowledge processes, we set up expert consultations, systematic reviews, and collaborative adaptive management procedures in collaboration with requesters, policy and decision-makers, stakeholders, and knowledge holders. Outputs included expert consultations, systematic review protocols, a group model and a policy brief. Important lessons learned were firstly that the scoping process, in which requesters and experts iteratively negotiate the scope, scale and synthesis methodology, is of paramount importance to maximize the scientific credibility and policy relevance of the output. Secondly, selection of a broad array of experts with diverse and complementary skills (including multidisciplinary background and a broad geographical coverage) and participation of all relevant stakeholders is crucial to ensure an adequate breath of expertise, better methodological choices, and maximal uptake of outcomes: Thirdly, as the most important challenge was expert and stakeholder engagement, a high visibility and reputation of BiodiversityKnowledge, supported by an incentive system for participation, will be crucial to ensure such engagement. We conclude that BiodiversityKnowledge has potential for a good performance in delivering assessments, but it requires adequate funding, trust-building among knowledge holders and stakeholders, and a proactive and robust interface with the policy and decision making communityPeer reviewe

Hybrid ventilation in two interconnected rooms with a buoyancy source

The design of energy efficient buildings and the potential for using solar energy for heating and cooling is contingent upon optimizing the building ventilation systems. In this paper we study the ventilation of two interconnected spaces, such as adjacent offices or areas in an open plan office. The goal is to locate return vents to increase the efficiency of night ventilation and to reduce energy consumption.The flow in two interconnected rooms of similar sizes is studied experimentally using a tank divided by an interior vertical wall. A forced buoyancy source with a finite volume flux is located in the ceiling of one-room and an unforced vent is opened in the ceiling of the other room.The goal of the study is to understand the transient cooling/heating that occurs in this two-room system when a forced cold-air vent is located in the ceiling of the first room and a return ventilation exit is located in the second. In particular, we investigate the effects of varying the number of openings and their vertical positions in the interconnecting wall. First, a single opening at the bottom, middle or top of the shared wall is examined. Second, the case of two openings in the wall is considered, with the openings located at the top–bottom,top –middle, bottom –middle, and finally at two mid locations in the wall. The results are compared with the one-room case, which represents the reference case. It was found that, irrespective of the number and locations of the openings, the flow evolves into a quasi-stationary stably stratified two-layer system, with the depths of the layers being different in each room.The average temperature inside each room initially decreases linearly with time and approaches the supply-air temperature at large times.This initial linear decrease holds until cold-air leaves the unforced room through the top-vent at time t_e. Subsequently, temperature decreases as an exponential function of time with a characteristic filling time s =V /Q_s ,where V is the total volume of both rooms and Q_s is the source volume flux. The efficiency of the ventilation depends on the time t_e, and this depends, in turn, on an exchange flow that is established between the two-rooms by the differences in density in each room. For a single opening, the exchange flow takes place as a two-way flow in the opening, while for two openings the flow is from the forced room through the lower opening and in the opposite direction through the upper opening. When the upper opening is located below the ceiling, this flow from the unforced room ‘shields ’the return vent from the dense fluid, thereby increasing the efficiency of the ventilation.Fil: Tovar, R.. Universidad Nacional Autónoma de México; MéxicoFil: Linden, P. F.. University of California at San Diego; Estados UnidosFil: Thomas, Luis Pablo. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Instituto de Física Arroyo Seco; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil; Argentin

The fast declining Type Ia supernova 2003gs, and evidence for a significant dispersion in near-infrared absolute magnitudes of fast decliners at maximum light

We obtained optical photometry of SN 2003gs on 49 nights, from 2 to 494 days after T(B_max). We also obtained near-IR photometry on 21 nights. SN 2003gs was the first fast declining Type Ia SN that has been well observed since SN 1999by. While it was subluminous in optical bands compared to more slowly declining Type Ia SNe, it was not subluminous at maximum light in the near-IR bands. There appears to be a bimodal distribution in the near-IR absolute magnitudes of Type Ia SNe at maximum light. Those that peak in the near-IR after T(B_max) are subluminous in the all bands. Those that peak in the near-IR prior to T(B_max), such as SN 2003gs, have effectively the same near-IR absolute magnitudes at maximum light regardless of the decline rate Delta m_15(B). Near-IR spectral evidence suggests that opacities in the outer layers of SN 2003gs are reduced much earlier than for normal Type Ia SNe. That may allow gamma rays that power the luminosity to escape more rapidly and accelerate the decline rate. This conclusion is consistent with the photometric behavior of SN 2003gs in the IR, which indicates a faster than normal decline from approximately normal peak brightness.Comment: 41 pages, 13 figures, to be published in the December, 2009, issue of the Astronomical Journa

Solutions of shallow-water equations in non-rectangular cross-section channels

Smooth solutions of the shallow-water equations for non-rectangular cross-sections channels are studied. It is found that a complete set of solutions can be classified in four Lie symmetry groups that show distinctive physical features.Fil: Thomas, Luis Pablo. Universidad Nacional del Centro de la Provincia de Buenos Aires.. Facultad de Ciencias Exactas. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Peña, Carlos César. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Departamento de Matemática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Barrenechea, Ana Lucía. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Departamento de Matemática; ArgentinaFil: Marino, Beatriz Maria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires.. Facultad de Ciencias Exactas. Departamento de Física; Argentin

Modelado en el laboratorio de la ventilación natural generada por diferencias de temperatura entre el exterior y el interior en una vivienda

Bajo requisitos de similaridad dinámica se analizan los flujos de ventilación natural generados por diferencias de temperatura en el modelo físico de una vivienda con un atrio central. Se utiliza la metodología basada en el uso de agua y agua salada para modelar, respectivamente, los movimientos del aire a temperatura ambiente y del más cálido, en cuyo caso la fuerza de flotación es debida a la diferencia de salinidad entre los fluidos. Abriendo las aberturas que comunican con el exterior, diferentes situaciones son representadas para mostrar las diferencias apreciables de la evolución de los flujos internos generados. Se obtiene un sistema de ventilación natural muy eficiente cuando las aberturas de la lucarna situada sobre el atrio y al menos una de las aberturas de la planta baja están abiertas y operando conjuntamente.Natural ventilation flows generated by temperature differences in the laboratory physical model of a house under dynamic similarity criteria are analyzed. The methodology based on the use of water and salt water is employed to model the movements of the ambient temperature air and the warmer air, respectively. In such a case the buoyancy force is caused by salinity difference between the fluids. By opening the windows and doors that communicate with the exterior and a central top roof monitor, different situations are represented to show the noticeable differences of the internal airflows evolution. A very efficient natural ventilation system is obtained when the roof monitor and lower openings are opened simultaneously.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES