587 research outputs found

    Casimir energy in spherical cavities

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    We calculate the Casimir energy at spherical cavities within a host made up of an arbitrary material described by a possibly dispersive and lossy dielectric response. To that end, we add to the coherent optical response a contribution that takes account of the incoherent radiation emitted by the host in order to guarantee the detailed balance required to keep the system at thermodynamic equilibrium in the presence of dissipation. The resulting boundary conditions allow a conventional quantum mechanical treatment of the radiation within the cavity from which we obtain the contribution of the cavity walls to the density of states, and from it, the thermodynamic properties of the system. The contribution of the cavity to the energy diverges as it incorporates the interaction energy between neighbor atoms in a continuum description. The change in the energy of an atom situated at the center of the cavity due to its interaction with the fluctuating cavity field is however finite. We evaluate the latter for a simple case.Comment: 9 pages, 4 figures, Proceedings of QFEXT07. To be published in J. Phys.

    Exploring the conditions leading to an exceptional early bloom of Dinophysis acuminata in northwest Spain during 2012

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    In a conceptual model proposed before, the onset of the upwelling season and availability of Mesodinium rubrum prey are essential conditions for the initiation of Dinophysis acuminata blooms in the Galician Rías Baixas (NW Spain). Distribution of sexual cysts from the previous year in the top sediment layer is an important parameter in forecasting models of cyst-forming species (e.g. Alexandrium spp.). But the existence of sexual cysts of Dinophysis spp. has not been confirmed, Dinophysis planozygotes can divide and produce vegetative cells directly, and it is possible that species of this genus do not rely on sexual cysts but on some kind of overwintering planktonic form as a seeding mechanism. Here we examine winter conditions—persistence or absence of overwintering cells of Dinophysis within the rías and the adjacent shelf and time of initiation of the upwelling season—from observations in the last 20 years. Our ultimate goal was to explain the abundance and early initiation in April 2012 of an extraordinary bloom of D. acuminata, in what appeared to be a mesoscale event affecting other regions in Western Europe. The dynamics of D. acuminata populations appeared tightly coupled to the upwelling season. Our results suggest that anomalous upwelling patterns (predominance of upwelling in winter) combined with the presence of overwintering (inoculum) cells lead to early initiation of the Dinophysis acuminata growth seasonEn prens

    Climate Variability and Oceanographic Settings Associated with Interannual Variability in the Initiation of Dinophysis acuminata Blooms

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    In 2012, there were exceptional blooms of D. acuminata in early spring in what appeared to be a mesoscale event affecting Western Iberia and the Bay of Biscay. The objective of this work was to identify common climatic patterns to explain the observed anomalies in two important aquaculture sites, the Galician RĂ­as Baixas (NW Spain) and Arcachon Bay (SW France). Here, we examine climate variability through physical-biological couplings, Sea Surface Temperature (SST) anomalies and time of initiation of the upwelling season and its intensity over several decades. In 2012, the mesoscale features common to the two sites were positive anomalies in SST and unusual wind patterns. These led to an atypical predominance of upwelling in winter in the Galician RĂ­as, and increased haline stratification associated with a southward advection of the Gironde plume in Arcachon Bay. Both scenarios promoted an early phytoplankton growth season and increased stability that enhanced D. acuminata growth. Therefore, a common climate anomaly caused exceptional blooms of D. acuminata in two distant regions through different triggering mechanisms. These results increase our capability to predict intense diarrhetic shellfish poisoning outbreaks in the early spring from observations in the preceding winter

    Evaluation of six single nucleotide polymorphisms for bovine traceability in the context of the argentine-chinese beef trade

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    Genetic traceability refers to methods associated with the identification of animals and their products through DNA characterization of individuals, breeds or species. To trace breeds, it is necessary to define the breed groups to analyze, and the most appropriate molecular marker set. The selection of genetic markers depends on the gene frequency distribution, the genetic distance among breeds and the presence of private alleles. In this study, we assessed six single nucleotide polymorphisms (SNPs) located in the DGAT1, TG, LEP, GH, FABP4 and GnRHR genes, as potential genetic markers to be included into a panel for genetic traceability for the identification of breed origin associated with the bovine beef trade. The results of the genetic characterization of four of the main Chinese cattle populations and of the principal breeds raised in Argentina and in the world (five Bos taurus and two B. indicus) suggest that these SNP markers can be successfully used as a part of an effective traceability system for the identification of cattle breed origin in the context of the Chinese meat imports, and in particular in the Argentine-Chinese beef trade.La trazabilidad genĂ©tica, la cual se basa en la identificaciĂłn de animales y sus productos, permite la identificaciĂłn individual, racial o de especie. Esta metodologĂ­a es Ăștil para detectar fraudes y valorizar producciones locales. Para llevar a cabo la trazabilidad es necesario definir los grupos raciales a analizar y el panel de marcadores mĂĄs apropiados a utilizar. La selecciĂłn de marcadores depende de la distribuciĂłn de las frecuencias gĂ©nicas, de la distancia genĂ©tica entre las razas y de la presencia de alelos privativos. El objetivo de este trabajo consistiĂł en evaluar seis polimorfismos de nucleĂłtido simple (SNPs) ubicados en los genes DGAT1, TG, LEP, GH, FABP4 y GnRHR como posibles marcadores genĂ©ticos apropiados para ser incluidos en un panel de trazabilidad para la identificaciĂłn de la raza de origen en el contexto de la comercializaciĂłn de carne bovina. Los resultados de la caracterizaciĂłn genĂ©tica de cuatro de las principales poblaciones bovinas chinas y de las razas mĂĄs importantes de nuestro paĂ­s (cinco Bos taurus y dos B. indicus) sugieren que los marcadores estudiados pueden ser utilizados exitosamente como parte de un sistema de trazabilidad efectivo para identificar el origen de la carne bovina en el contexto de la importaciĂłn de carne en el mercado chino y en particular en el comercio entre Argentina y China.Fil: Ripoli, MarĂ­a VerĂłnica. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico La Plata. Instituto de GenĂ©tica Veterinaria "Ingeniero Fernando Noel Dulout"; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Wei, S.. Chinese Academy of Agricultural Sciences; ChinaFil: Rogberg Muñoz, Andres. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico La Plata. Instituto de GenĂ©tica Veterinaria "Ingeniero Fernando Noel Dulout"; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Guo, B. L.. Chinese Academy of Agricultural Sciences; ChinaFil: Goszczynski, Daniel Estanislao. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico La Plata. Instituto de GenĂ©tica Veterinaria "Ingeniero Fernando Noel Dulout"; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Fernandez, MarĂ­a Elena. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico La Plata. Instituto de GenĂ©tica Veterinaria "Ingeniero Fernando Noel Dulout"; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Melucci, L.. Instituto Nacional de TecnologĂ­a Agropecuaria. Centro Regional Buenos Aires. EstaciĂłn Experimental Agropecuaria Balcarce; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Liron, Juan Pedro. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico La Plata. Instituto de GenĂ©tica Veterinaria "Ingeniero Fernando Noel Dulout"; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Villarreal, E.. Instituto Nacional de TecnologĂ­a Agropecuaria. Centro Regional Buenos Aires. EstaciĂłn Experimental Agropecuaria Balcarce; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Wei, Y. M.. Chinese Academy of Agricultural Sciences; ChinaFil: Giovambattista, Guillermo. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico La Plata. Instituto de GenĂ©tica Veterinaria "Ingeniero Fernando Noel Dulout"; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentin

    Evaluation of six single nucleotide polymorphisms for bovine traceability in the context of the argentine-chinese beef trade

    Get PDF
    Genetic traceability refers to methods associated with the identification of animals and their products through DNA characterization of individuals, breeds or species. To trace breeds, it is necessary to define the breed groups to analyze, and the most appropriate molecular marker set. The selection of genetic markers depends on the gene frequency distribution, the genetic distance among breeds and the presence of private alleles. In this study, we assessed six single nucleotide polymorphisms (SNPs) located in the DGAT1, TG, LEP, GH, FABP4 and GnRHR genes, as potential genetic markers to be included into a panel for genetic traceability for the identification of breed origin associated with the bovine beef trade. The results of the genetic characterization of four of the main Chinese cattle populations and of the principal breeds raised in Argentina and in the world (five Bos taurus and two B. indicus) suggest that these SNP markers can be successfully used as a part of an effective traceability system for the identification of cattle breed origin in the context of the Chinese meat imports, and in particular in the Argentine-Chinese beef trade.La trazabilidad genĂ©tica, la cual se basa en la identificaciĂłn de animales y sus productos, permite la identificaciĂłn individual, racial o de especie. Esta metodologĂ­a es Ăștil para detectar fraudes y valorizar producciones locales. Para llevar a cabo la trazabilidad es necesario definir los grupos raciales a analizar y el panel de marcadores mĂĄs apropiados a utilizar. La selecciĂłn de marcadores depende de la distribuciĂłn de las frecuencias gĂ©nicas, de la distancia genĂ©tica entre las razas y de la presencia de alelos privativos. El objetivo de este trabajo consistiĂł en evaluar seis polimorfismos de nucleĂłtido simple (SNPs) ubicados en los genes DGAT1, TG, LEP, GH, FABP4 y GnRHR como posibles marcadores genĂ©ticos apropiados para ser incluidos en un panel de trazabilidad para la identificaciĂłn de la raza de origen en el contexto de la comercializaciĂłn de carne bovina. Los resultados de la caracterizaciĂłn genĂ©tica de cuatro de las principales poblaciones bovinas chinas y de las razas mĂĄs importantes de nuestro paĂ­s (cinco Bos taurus y dos B. indicus) sugieren que los marcadores estudiados pueden ser utilizados exitosamente como parte de un sistema de trazabilidad efectivo para identificar el origen de la carne bovina en el contexto de la importaciĂłn de carne en el mercado chino y en particular en el comercio entre Argentina y China.Instituto de GenĂ©tica Veterinari

    A Lean Six Sigma framework for the reduction of ship loading commercial time in the iron ore pelletising industry

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    © 2016 Informa UK Limited, trading as Taylor & Francis Group. Abstract: Evidence suggests that specifically designed frameworks to implement Lean Six Sigma (LSS) projects to tackle particular problems are more effective than ‘generic’ versions. This paper proposes an implementation framework to effectively deploy LSS to improve a key operation and performance indicator, i.e. ship loading commercial time, of one of the largest world producer of iron ore. This article therefore contributes with a refined framework to effectively implement LSS, and documents its successful application and effectiveness within the context of the case organisation. The LSS framework and project contributed in helping the studied organisation to improve both the capability of its ship loading process and commercial time by more than 30%, resulting in operational savings in the range of $300,000 USD per year. The systematic nature of the framework proposed also helped the organisation to establish a standardised routine to improve its operations. Managerial implications exposing the challenges faced during the implementation of LSS are also discussed to serve as lessons learnt to be considered in other LSS projects. Managers and engineers incharge of improving operations and processes can benefit from this paper as it can be used as a guide to direct the conduction of LSS projects and the empirical application of its principles and tools

    Metal-substituted protein MRI contrast agents engineered for enhanced relaxivity and ligand sensitivity

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    Engineered metalloproteins constitute a flexible new class of analyte-sensitive molecular imaging agents detectable by magnetic resonance imaging (MRI), but their contrast effects are generally weaker than synthetic agents. To augment the proton relaxivity of agents derived from the heme domain of cytochrome P450 BM3 (BM3h), we formed manganese(III)-containing proteins that have higher electron spin than their native ferric iron counterparts. Metal substitution was achieved by coexpressing BM3h variants with the bacterial heme transporter ChuA in Escherichia coli and supplementing the growth medium with Mn3+-protoporphyrin IX. Manganic BM3h variants exhibited up to 2.6-fold higher T1 relaxivities relative to native BM3h at 4.7 T. Application of ChuA-mediated porphyrin substitution to a collection of thermostable chimeric P450 domains resulted in a stable, high-relaxivity BM3h derivative displaying a 63% relaxivity change upon binding of arachidonic acid, a natural ligand for the P450 enzyme and an important component of biological signaling pathways. This work demonstrates that protein-based MRI sensors with robust ligand sensitivity may be created with ease by including metal substitution among the toolkit of methods available to the protein engineer.National Institutes of Health (U.S.) (NIH Grant R01-DA28299 )National Institutes of Health (U.S.) (NIH NRSA Fellowship (Award F32-GM087102))California Institute of Technology (Caltech Jacobs Grant

    Allergy education and training for physicians.

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    The increasing prevalence of allergic diseases has placed a significant burden on global healthcare and society as whole. This has necessitated a rapid development of "allergy" as a specialist area. However, as allergy is so common and, for most, relatively easy to diagnose and control, all clinicians need to have basic knowledge and competence  to manage  mild disease and recognize when referral is required. The allergology specialty has not yet been recognized in many countries and even where allergy is fully recognized as a specialty, the approach to training in allergy differs significantly. In the light of recent developments in allergy diagnosis and management, there is an urgent need to harmonize core competences for physicians, as well as the standardization of core principles for medical education and post-graduate training in allergy. All physicians and allied health professionals must appreciate the multidisciplinary team (MDT) approach to allergy, which is key to achieving the highest standards in holistic care. Due to worldwide variation in resources and personnel, some MDT roles will need to be absorbed by the treating physician or other healthcare professionals. We draw particular attention to the role of psychological input for all allergy patients, dietetic input in the case of food allergy and patient education to support all patients in the supported self-management of their condition on a daily basis. A strong appreciation of these multidisciplinary aspects will help physicians provide quality patient-centered care. We consider that harmonization of allergy components within undergraduate curricula is crucial to ensure all physicians develop the appropriate allergy-related knowledge and skills, particularly in light of inconsistencies seen in the primary care management of allergy. This review from the World Allergy Organization (WAO) Education and Training Committee also outlines allergy-related competences required of physicians working with allergic patients and provides recommendations to promote harmonization of allergy training and practice worldwide

    Modulation of Brain Activity during Action Observation: Influence of Perspective, Transitivity and Meaningfulness

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    The coupling process between observed and performed actions is thought to be performed by a fronto-parietal perception-action system including regions of the inferior frontal gyrus and the inferior parietal lobule. When investigating the influence of the movements' characteristics on this process, most research on action observation has focused on only one particular variable even though the type of movements we observe can vary on several levels. By manipulating the visual perspective, transitivity and meaningfulness of observed movements in a functional magnetic resonance imaging study we aimed at investigating how the type of movements and the visual perspective can modulate brain activity during action observation in healthy individuals. Importantly, we used an active observation task where participants had to subsequently execute or imagine the observed movements. Our results show that the fronto-parietal regions of the perception action system were mostly recruited during the observation of meaningless actions while visual perspective had little influence on the activity within the perception-action system. Simultaneous investigation of several sources of modulation during active action observation is probably an approach that could lead to a greater ecological comprehension of this important sensorimotor process

    Lean road transportation – A systematic method for the improvement of road transport operations

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    Road transportation has become an important factor in international trade and the management of supply chains. However, this form of product logistics has generally been considered inefficient. Traditionally, practical inefficiencies of road transportation have been addressed through mathematical modelling, operations research-based methods, and simulation. This paper presents an alternative systematic approach to improve road transport operations based on lean thinking and the reduction of the seven transportation extended wastes (STEWs). To do this, the paper reviews the extant literature in the area of lean road transportation, providing a structured research definition of the application of lean thinking in road transport operations and hence guidance on the limited research conducted in this field. The systematic lean transportation method is then presented and empirically tested through a case study in a Mexican firm. The results obtained from the case study indicate that the proposed systematic lean method is an effective alternative for the improvement of road transport operations, with the number of distribution routes and distance travelled being reduced by 27% and 32% respectively. The proposed method can be used by organisations as a guide to help them improve their road transport operations. In addition, the paper’s aim is to contribute by stimulating scholars to further study the application of lean thinking and waste reduction in road transport operations
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