196 research outputs found
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
nanotecnologÃa 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 ingenierÃa 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 existÃa 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 caracterÃsticas 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 mÃnima 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 perÃodo 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 centÃmetros 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 fÃsicas del suelo
Late Holocene Aleppo pine (Pinus halepensis Miller) woodlands in Mallorca (Balearic Islands, Western Mediterranean): Investigation of their distribution and the role of human management based on anthracological, dendro-anthracological and archaeopalynological data
The pioneering nature of Mediterranean pines and their phytosociological role have been largely discussed in relation to different agents (e.g., edaphic, climatic or anthropogenic). In this context, Aleppo pine is one of the most widespread pine species in the Mediterranean basin, as it is especially adapted to climatic constraints, such as drought and high seasonality, and has a high tolerance for salinity and strong coastal winds. It is also well adapted to regeneration after anthropogenic landscape disturbances, highlighting its important after-fire regeneration rates. In this sense, phytosociological studies conducted in Mediterranean landscapes have found that this species'' wide distribution is mostly due to its rapid regeneration after human landscape transformation, including fire, and the abandonment of agricultural lands. Aleppo pine is considered to broadly develop after human action in sclerophyllous formation, in which it would be scarce or absent without human intervention. Parallel, paleoenvironmental and archaeobotanical studies have attempted to trace these trends back to prehistoric times to investigate this species'' role in Late Pleistocene and Holocene vegetation and evaluate the role of climate and human action in its diachronic dynamics. In this study, we present a compendium of anthracological, dendro-anthracological and archaeopalyonological data with the objective of (i) investigating the nature and distribution of Aleppo pine on the island of Mallorca and (ii) evaluating the possibility that human action could have resulted in the spread of this pine species during the first two millennia of permanent human occupation of the island (c. 2300 cal. BCE–1st-century ACE). Investigating these archaeobotanical datasets, as well as making comparisons with anthracological and paleoenvironmental studies in neighbouring Mediterranean zones (Iberia), allowed us to attest that Aleppo pine is a natural, pre-human component of the Holocene vegetation of the island, and it is especially well-adapted to coastal environments. Moreover, we describe the trends and characteristics of the human management of pine woodlands through anthracology and dendro-anthracology, suggesting that human action did not provoke widespread growth of Aleppo pine in Mallorca at the expense of other vegetation types during prehistory. Such processes, well-documented by current phytosociological studies, probably began at some unknown point after the Romanisation of the island
Quesungual slash and mulch agroforestry system (QSMAS): Improving crop water productivity, food security and resource quality in the sub-humid tropics
The knowledge and principles generated by CPWF-PN15 confirm that QSMAS can be a model production system for implementing conservation agriculture to achieve food security and sustainable development in drought-prone areas of hillsides in the sub-humid tropics, while providing ecosystem services in the face of land degradation and climate change. As an adoptable option to replace the slash and burn traditional system, QSMAS can improve smallholder livelihoods through eco-efficient use and conservation of natural resources. Participatory validation activities suggest that the conservation agriculture principles embedded in QSMAS can be readily accepted by resource- poor farmers and local authorities in similar agroecosystems
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 0.38Â petagrams of carbon (0.23-0.53Â 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
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