A Mathematical Model for the Validation of Safe Air-Blast Chilling of Cooked Hams

An integrated mathematical model of heat transfer and temperature-dependent bacterial growth was developed to validate the safety of cooked hams during air-blast chilling. Heat transfer through a cooked ham was mathematically modeled and analyzed with a finite element method. Response of bacteria to temperatures was quantitatively described using predictive microbiology. The cumulative effect of temperature history on the bacterial growth was taken into account in the model. For chilling cooked hams from 71°C to 10°C, the maximum error between the predicted and experimental core temperature was within 2.2°C, and the deviation between the predicted and measured total weight losses was 1.1%. The bacterial growth kinetics was validated using the data from the literature. The integrated model of heat transfer and bacterial growth provided valuable insights into air-blast chilling of cooked meats for risk assessment of the final products

Cápsulas de Gelatina Blanda

El PAP 4I02A Programa de apoyo a la investigación y desarrollo en nanociencias y nanotecnología I- Cápsulas de Gelatina Blanda tiene como objetivo la construcción de un nuevo edificio especializado en la producción de medicamentos en forma de cápsulas de gelatina blanda. Durante el semestre, se buscó apoyar con los documentos necesarios para la aprobación del proyecto, ya que se redefinió el alcance de éste. Una vez obtenida la aprobación, se trabajó con la generación y revisión de documentos y diseños de ingeniería para marcar hitos de avance en el proyecto con el fin de iniciar la fase de implementación.ITESO, A.C

Percepciones de directores y ejecutivos del Instituto Colombiano Agropecuario acerca del rol del director regional de desarrollo rural.

Se determinó si existía un conflicto entre directores y ejecutivos en la forma de percibir las funciones del Director Regional de Desarrollo Rural del Instituto. Se elaboró un cuestionario dividido en 2 secciones, la primera buscaba obtener respuesta de los funcionarios con relación a edad, último nivel académico obtenido, experiencia de trabajo con el Instituto y experiencia en Desarrollo Rural y la segunda hace referencia a las funciones que puede desempeñar el Director. Tanto directores como ejecutivos están de acuerdo con el rol que puede desempeñar en el Instituto el Director Regional de Desarrollo Rural. Las diferencias entre los grupos representados y sus respuestas se refieren más que todo al nivel en el cual están de acuerdo y no a los niveles en que no se encuentran de acuerdo. Ambos grupos percibieron que el rol de Director incluye 38 funciones del cuestionario y que tres de los enunciados no describen funciones. Existen diferencias marcadas entre ejecutivos y Directores para las características de: edad, entrenamiento y experiencia de trabajo con el Institut

Stubble mulching and minimum tillage with barley

In the Colombian Tibaitatá CNI (2500 m.a.s.l., 14°C an bimodal rainfall) was carried out a soil management as an alternative for minimizing environmental constraints for barley or wheat production in a medial isomesic Dystric Haplustand, Some progress has been obtained by adoption of minimum tillage with or without straw in the arable layer, to minimize the negative effects of both low and bad distributed rainfall during the cropping season. By reducing soil disturbance, grain yield was better and had an increase in water content in the surface arable layer, associated with an improving penetrability. Other units using cereal straw (4 and 8 t/ha)and minimum tillage only improve physical soil  properties.En el Centro Nacional de Investigaciones Tibaitatá (2.550 m.s.n.m., 14°C y una precipitación bimodal de 950 mm) se llevó a cabo un estudio para evaluar el manejo del suelo como alternativa para minimizar las restricciones ambientales para cebada o trigo en un Dystric Haplustand medial isomésico. Cierto progreso se ha logrado mediante la adopción de la labranza mínima con o sin la incorporación del rastrojo del cereal en la capa arable, para minimizar el efecto de la baja e inadecuada distribución de las lluvias durante el período de crecimiento del cultivo. Reduciendo la disturbación del suelo, el rendimiento de grano fue mayor, hubo un incremento en el contenido de agua de los primeros centímetros de la capa arable, asociado con un incremento en la penetrabilidad. Al incorporar entre 4 y 8 toneladas de rastrojo con labranza reducida, solamente mejoraron algunas propiedades físicas del suelo

MIMO Passive Control Systems Are Not Necessarily Robust

Via several cases of study it is shown that a passive multivariable linear control system, contrary to its single input single output counterpart, may not be robust. Moreover, it is shown that lack of robustness can be exposed via the multivariable structure function

Drought impact on forest carbon dynamics and fluxes in Amazonia

In 2005 and 2010 the Amazon basin experienced two strong droughts, driven by shifts in the tropical hydrological regime possibly associated with global climate change, as predicted by some global models. Tree mortality increased after the 2005 drought, and regional atmospheric inversion modelling showed basin-wide decreases in CO2 uptake in 2010 compared with 2011 (ref. 5). But the response of tropical forest carbon cycling to these droughts is not fully understood and there has been no detailed multi-site investigation in situ. Here we use several years of data from a network of thirteen 1-ha forest plots spread throughout South America, where each component of net primary production (NPP), autotrophic respiration and heterotrophic respiration is measured separately, to develop a better mechanistic understanding of the impact of the 2010 drought on the Amazon forest. We find that total NPP remained constant throughout the drought. However, towards the end of the drought, autotrophic respiration, especially in roots and stems, declined significantly compared with measurements in 2009 made in the absence of drought, with extended decreases in autotrophic respiration in the three driest plots. In the year after the drought, total NPP remained constant but the allocation of carbon shifted towards canopy NPP and away from fine-root NPP. Both leaf-level and plot-level measurements indicate that severe drought suppresses photosynthesis. Scaling these measurements to the entire Amazon basin with rainfall data, we estimate that drought suppressed Amazon-wide photosynthesis in 2010 by 0.38 petagrams of carbon (0.23-0.53 petagrams of carbon). Overall, we find that during this drought, instead of reducing total NPP, trees prioritized growth by reducing autotrophic respiration that was unrelated to growth. This suggests that trees decrease investment in tissue maintenance and defence, in line with eco-evolutionary theories that trees are competitively disadvantaged in the absence of growth. We propose that weakened maintenance and defence investment may, in turn, cause the increase in post-drought tree mortality observed at our plots.Gordon and Betty Moore FoundationNatural Environment Research Council (NERC)EU FP7 Amazalert (282664) projectEU FP7GEOCARBON (283080) projectNational Council for Scientific and Technological Development (CNPq, Brazil)ARC - fellowship awardERC - Advanced Investigator AwardRoyal Society - Wolfson Research Merit AwardJackson FoundationJohn Fell Fun

Human Health Risk Assessment (HHRA) for environmental development and transfer of antibiotic resistanc

This is the final version of the article. Available from NIEHS via the DOI in this record.Open access journalBACKGROUND: Only recently has the environment been clearly implicated in the risk of antibiotic resistance to clinical outcome, but to date there have been few documented approaches to formally assess these risks. OBJECTIVE: We examined possible approaches and sought to identify research needs to enable human health risk assessments (HHRA) that focus on the role of the environment in the failure of antibiotic treatment caused by antibiotic-resistant pathogens. METHODS: The authors participated in a workshop held 4-8 March 2012 in Québec, Canada, to define the scope and objectives of an environmental assessment of antibiotic-resistance risks to human health. We focused on key elements of environmental-resistance-development "hot spots," exposure assessment (unrelated to food), and dose response to characterize risks that may improve antibiotic-resistance management options. DISCUSSION: Various novel aspects to traditional risk assessments were identified to enable an assessment of environmental antibiotic resistance. These include a) accounting for an added selective pressure on the environmental resistome that, over time, allows for development of antibiotic-resistant bacteria (ARB); b) identifying and describing rates of horizontal gene transfer (HGT) in the relevant environmental "hot spot" compartments; and c) modifying traditional dose-response approaches to address doses of ARB for various health outcomes and pathways. CONCLUSIONS: We propose that environmental aspects of antibiotic-resistance development be included in the processes of any HHRA addressing ARB. Because of limited available data, a multicriteria decision analysis approach would be a useful way to undertake an HHRA of environmental antibiotic resistance that informs risk managers.This manuscript was conceived at a workshop (Antimicrobial Resistance in the Environment: Assessing and Managing Effects of Anthropogenic Activities) held 4–8 March 2012 in Montebello, Québec, Canada. The workshop was sponsored by the Canadian Society of Microbiologists, with financial support from AstraZeneca Ltd.; Pfizer Animal Health; F. Hoffman-La Roche Ltd.; GlaxoSmithKline; Unilever; Huvepharma; the American Cleaning Institute; the Canadian Animal Health Institute; the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety; Health Canada; and the Public Health Agency of Canada

On the distinctive call of a threatened phenotype of Allobates femoralis (Anura: Aromobatidae) and its recognition by allopatric conspecific males

ABSTRACT The brilliant-thighed frog [Allobates femoralis (Boulenger, 1884)]; is distributed across the Amazon basin and aggregates several allopatric evolutionary lineages, some of which present variation in their advertisement calls. In 2009, an unregistered call phenotype was discovered in the region of Altamira and Vitória do Xingu, State of Pará, Brazil, where males emit advertisement calls formed by six notes, differing from the typical four-note calls described for other A. femoralis populations. In this study, we describe in detail these untypical calls. Additionally, we test whether the aggressive responses of males of a 4-note reference population (Reserva Ducke - RFAD, in Manaus, State of Amazonas) is differential towards the 6-note calls of males recorded in Altamira (Pará State), and towards 4-note calls recorded in one location at the Tapajós-Xingu interfluve (Belterra, Pará State), and in RFAD. Playback experiments were conducted between 2011-2012, and used standardized stimuli produced from natural call recordings. A total of 30 independent experiments were conducted, 10 for each stimuli class. We measured the phonotaxis of focal males in relation to the loudspeaker, considering the time to orientation and the time to approach the loudspeaker. We found that not all A. femoralis males at RFAD promptly recognize calls from males recorded in Altamira. However, when considering only males who approached the loudspeaker, differences in aggressive reactions were not seen between stimuli classes. Our findings show that the ability to recognize calls from Altamira as belonging to co-specific males is not universal among males at RFAD. The new A. femoralis phenotype occurs in areas potentially impacted by the Belo Monte hydroelectric complex and complementary studies indicate that no gene flow exists between this group and A. femoralis from adjacent regions. Hence, developments in Altamira may put this incipient speciation process at risk