Transient micro heat transfer in a gas confined between parallel plates due to a sudden increase of the wall temperature

This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute.The transient heat transfer problem through a rarefied gas confined between parallel plates maintained at different temperatures is investigated. The theoretical formulation is based on the linear BGK kinetic model subject to Maxwell diffuse reflection. The governing time dependent equation is solved by using the discrete velocity method. Results are presented for the number density, macroscopic velocity, heat flux and temperature distributions in the whole range of the Knudsen number. The results are compared with direct Monte Carlo simulations and good agreement is found for small temperature variations.This study is funded from the European Community's Seventh Framework Programme (ITN - FP7/2007-2013) under grant agreement n° 215504

Experimental phase functions of mm-sized cosmic dust grains

We present experimental phase functions of three types of millimeter-sized dust grains consisting of enstatite, quartz and volcanic material from Mount Etna, respectively. The three grains present similar sizes but different absorbing properties. The measurements are performed at 527 nm covering the scattering angle range from 3 to 170 degrees. The measured phase functions show two well defined regions i) soft forward peaks and ii) a continuous increase with the scattering angle at side- and back-scattering regions. This behavior at side- and back-scattering regions are in agreement with the observed phase functions for the Fomalhaut and HR 4796A dust rings. Further computations and measurements (including polarization) for millimeter sized-grains are needed to draw some conclusions about the fluffy or compact structure of the dust grains

Successful organizational learning in the management of agricultural research and innovation: The Mexican produce foundations

"Since the 1980s, developing countries' agriculture has become more complex and diversified. In general, the public research and extension institutions in these countries were criticized for not participating in the emergence of the most dynamic agricultural markets. In recent years, many of these institutions have struggled to adapt to the new environment but they could not overcome the hurdles posed by organizational rigidities, strict public regulations, deteriorating human capital, shrinking budgets and a model of science that hampered their integration into dynamic innovation processes. In general, developing countries applied similar agricultural research policies: separation of financing and implementation of research, reductions in direct budgetary allocations to research and extension institutions, elimination or major reduction of public extension, and introduction of competitive grants programs to induce a transformation of research organizations. Strong anecdotal information suggests that these policies had limited impact on the quality and pertinence of research, and on the performance of the public research institutions. Using a different set of instruments, the Mexican Produce Foundations (PF) had major and diverse impacts on the agricultural innovation and research systems. These impacts resulted mostly from activities the PF introduced as they learned to manage funds for research and extension, and to a lesser extent from the activities they were created for, i.e., manage a competitive fund for agricultural research and extension. The PF were able to introduce these activities because they developed strong abilities to learn, including identifying knowledge gaps and defining strategies to fill them. The questions this report seeks to answer are how an organization that manages public funds for research and extension could sustain organizational innovations over extended periods, and how it could learn and adapt to maximize its impact on the agricultural innovation system. Previous studies found that human resources, organizational cultures and governance structures are three of the most important factors influencing institutional change and innovative capabilities. Despite their importance, these factors have been largely neglected in the literature on agricultural research and extension policies. This document analyzes what role these factors played in the Mexican experience." from textAgricultural research, Agricultural innovation, Developing countries,

Inter-band B(E2) transition strengths in odd-mass heavy deformed nuclei

Inter-band B(E2) transition strengths between different normal parity bands in 163Dy and 165Er are described using the pseudo-SU(3) model. The Hamiltonian includes Nilsson single-particle energies, quadrupole-quadrupole and pairing interactions with fixed, parametrized strengths, and three extra rotor terms used to fine tune the energy spectra. In addition to inter-band transitions, the energy spectra and the ground state intra-band B(E2) strengths are reported. The results show the pseudo-SU(3) shell model to be a powerful microscopic theory for a description of the normal parity sector in heavy deformed odd-A nuclei.Comment: 4 figures, 2 table

Natural killer (NK) cell response to virus infections in mice with severe combined immunodeficiency. The stimulation of NK cells and the NK cell-dependent control of virus infections occur independently of T and B cell function

The activation, proliferation, and antiviral properties of natural killer (NK) cells were examined in severe combined immunodeficiency (SCID) mice to determine the influence of mature T or B cells on virus-induced NK cell functions and to more conclusively determine the antiviral properties of prototypical CD3- NK cells. NK cells were activated to high levels of cytotoxicity 3 d after infection of mice with lymphocytic choriomeningitis virus (LCMV) or murine cytomegalovirus (MCMV). Analyses of spleen leukocytes from LCMV-infected mice by a variety of techniques indicated that the NK cells proliferated and increased in number during infection. Propidium iodide staining of the DNA of cycling cells revealed that the great majority of proliferating spleen leukocytes 3 d after LCMV infection was of the NK cell phenotype (CD3-, Ig-, Mac-1+, CZ1+, 50% Thy-1+), in contrast to uninfected mice, whose proliferating cells were predominantly of other lineages. Analyses of the NK cell responses over a 2 wk period in control CB17 mice infected with MCMV indicated a sharp rise in serum interferon (IFN) and spleen NK cell activity early (days 3-5) in infection, followed by sharp declines at later stages. In SCID mice the IFN levels continued to rise over a 10-d period, whereas the NK cell response peaked on day 3-5 and gradually tapered. In contrast to the immunocompetent CB17 mice, SCID mice did not clear the MCMV infection and eventually succumbed. SCID mice, again in contrast to immunocompetent CB17 mice, also failed to clear infections with LCMV and Pichinde virus (PV); these mice, infected as adults, did not die but instead developed long-term persistent infections. Depletion of the NK cells in vivo with antiserum to asialo GM1 rendered both SCID and CB17 control mice much more sensitive to MCMV infection, as shown by titers of virus in organs and by survival curves. In contrast, similar depletions of NK cells did not enhance the titers of the NK cell-resistant virus, LCMV. Two variants of PV, one sensitive to NK cells and the other selected for resistance to NK cells by in vivo passage, were also tested in NK cell-depleted SCID mice. The NK-sensitive PV replicated to higher titers in NK cell-depleted SCID mice, whereas the titers of the NK cell-resistant PV were the same, whether or not the mice had NK cells. These experiments support the concept that CD3- prototypical NK cells mediate resistance to NK cell-sensitive viruses via a mechanism independent of antiviral or natural antibody.(ABSTRACT TRUNCATED AT 400 WORDS

The Fading of Symmetry Non-restoration at Finite Temperature

The fate of symmetries at high temperature determines the dynamics of the very early universe. It is conceivable that temperature effects favor symmetry breaking instead of restoration. Concerning global symmetries, the non-linear sigma model is analyzed in detail. For spontaneously broken gauge symmetries, we propose the gauge boson magnetic mass as a ``flag'' for symmetry (non)-restoration. We consider several cases: the standard model with one and two Higgs doublets in the perturbative regime, and the case of a strongly interacting Higgs sector. The latter is done in a model independent way with the tools provided by chiral Lagrangians. Our results clearly point towards restoration, a pattern consistent with recent lattice computations for global symmetries. In addition, we explicitly verify $BRST$ invariance for gauge theories at finite temperature.Comment: 28 pages, Latex2e, 28 figures, two typos corrected, conclusions remain unchange

Auslander-Buchweitz approximation theory for triangulated categories

We introduce and develop an analogous of the Auslander-Buchweitz approximation theory (see \cite{AB}) in the context of triangulated categories, by using a version of relative homology in this setting. We also prove several results concerning relative homological algebra in a triangulated category \T, which are based on the behavior of certain subcategories under finiteness of resolutions and vanishing of Hom-spaces. For example: we establish the existence of preenvelopes (and precovers) in certain triangulated subcategories of \T. The results resemble various constructions and results of Auslander and Buchweitz, and are concentrated in exploring the structure of a triangulated category \T equipped with a pair (\X,\omega), where \X is closed under extensions and $\omega$ is a weak-cogenerator in \X, usually under additional conditions. This reduces, among other things, to the existence of distinguished triangles enjoying special properties, and the behavior of (suitably defined) (co)resolutions, projective or injective dimension of objects of \T and the formation of orthogonal subcategories. Finally, some relationships with the Rouquier's dimension in triangulated categories is discussed.Comment: To appear at: Appl. Categor. Struct. (2011); 22 page

Stochastic and deterministic dynamics of intrinsically irregular firing in cortical inhibitory interneurons

Most cortical neurons fire regularly when excited by a constant stimulus. In contrast, irregular-spiking (IS) interneurons are remarkable for the intrinsic variability of their spike timing, which can synchronize amongst IS cells via specific gap junctions. Here, we have studied the biophysical mechanisms of this irregular spiking in mice, and how IS cells fire in the context of synchronous network oscillations. Using patch-clamp recordings, artificial dynamic conductance injection, pharmacological analysis and computational modeling, we show that spike time irregularity is generated by a nonlinear dynamical interaction of voltage-dependent sodium and fast-inactivating potassium channels just below spike threshold, amplifying channel noise. This $\textit{active irregularity}$ may help IS cells synchronize with each other at gamma range frequencies, while resisting synchronization to lower input frequencies.Biotechnology and Biological Sciences Research Council, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Cambridge Overseas Trus

Alergia à proteína do leite de vaca, qualidade de vida e estilos parentais

Introduction: Cow’s milk protein allergy requires changes in family habits to maintain children’s health. Objective: This study evaluated the effects of cow’s milk protein allergy on the health of children, the quality of life of parents and children, and the adopted parental styles. Methods: Control case study. The case group consisted of children with cow’s milk protein allergy, from eight months to five years old, and those guardians, and the Control Group, for healthy children of the same age group, and their parents. The quality of life of the child (TNO-AZL Preschool Children Quality of Life) and the caregiver (SF-36) were evaluated; parental style (Parental Beliefs and Care Practices Scale); and socioeconomic and health data of the child. The Mann-Whitney test was used to compare the groups (p <0.05). Results: 76 dyads from the case group and 44 from the control group participated. Children with cow’s milk protein allergy had a lower quality of life in the health dimension, worse nutritional status, followed up with a larger number of health professionals. Those in charge of the case group offered less body stimulation to the children. Those in the control group had a lower quality of emotional life. Conclusions: Cow’s milk protein allergy had an impact on the health and nutritional status of children, on the corporal stimulation received by the children, and on the quality of emotional life of those guardians.Introdução: A alergia à proteína do leite de vaca requer alterações dos hábitos familiares para manutenção das condições de saúde das crianças. Objetivo: Este estudo analisou os efeitos da alergia à proteína do leite de vaca sobre a saúde de crianças, qualidade de vida de responsáveis e crianças e sobre os estilos parentais adotados. Método: Estudo caso controle. O grupo caso foi constituído por crianças com alergia à proteína do leite de vaca, de oito meses a cinco anos de idade, e seus responsáveis, e o Grupo Controle, por crianças saudáveis, de mesma faixa etária, e seus responsáveis. Foram avaliadas a qualidade de vida da criança (TNO-AZL Preschool Children Quality of Life) e do responsável (SF-36); estilo parental (Escala de Crenças Parentais e Práticas de Cuidado); e dados socioeconômicos e de saúde da criança. O teste de Mann-Whitney foi utilizado para comparar os grupos (p <0,05). Resultados: Participaram 26 díades do grupo caso e 44 do grupo controle. Crianças com alergia proteína do leite de vaca apresentaram menor qualidade de vida na dimensão saúde, pior estado nutricional, realizaram acompanhamento com maior número de profissionais da saúde. Os responsáveis do grupo caso ofereceram menor estimulação corporal às crianças. Responsáveis do grupo controle apresentaram menor qualidade de vida emocional. Conclusão: A alergia à proteína do leite de vaca impactou na saúde e no estado nutricional das crianças, na estimulação corporal recebida pelas crianças, e na qualidade de vida emocional dos responsáveis