Domain walls in supersymmetric QCD

We consider domain walls that appear in supersymmetric SU(N) with one massive flavour. In particular, for N > 3 we explicitly construct the elementary domain wall that interpolates between two contiguous vacua. We show that these solutions are BPS saturated for any value of the mass of the matter fields. We also comment on their large N limit and their relevance for supersymmetric gluodynamics.Comment: 4 pages, 1 figure, uses latex with hep99 class files. Presented at the International Europhysics Conference in High Energy Physics, Tampere (Finland) 15-21 July 199

Synaptic Transmission-Calcium Channels and Neurotransmiters Releasing

La comunicación neuronal en el sistema nervioso está mediada, en la gran mayoría de animales, por la transmisión sináptica química. Generalmente esta comunicación ocurre mediante la liberación de una sustancia transmisora en el terminal presináptico. Este transmisor sináptico se une a receptores postsinápticos y da lugar a una respuesta postsináptica en la célula blanco. La liberación del transmisor en la región presináptica, al parecer, es desencadenada por un aumento transitorio del calcio intracelular en el sitio de liberación. Este aumento se logra, principalmente, por la activación de canales de calcio dependientes de voltaje (VGCC), lo que da lugar a un ingreso de iones de calcio en el citosol presináptico, que desencadena la fusión de las vesículas sinápticas y la liberación del neurotransmisor. En este artículo se revisan las características moleculares y funcionales de los VGCC necesarias para la comprensión de alteraciones patológicas como las canalopatías y la transmisión sináptica anormal. Metodología: se consultaron las bases de datos Medline, Pubmed y los e-journals de la Biblioteca de la Universidad de Columbia, correspondientes a los años 1990 a 2004. Resultados: durante la última década se han logrado avances significativos en los aspectos moleculares y en la genética de los canales dependientes de voltaje. La integración de este conocimiento con la neurofisiología funcional y la neurología clínica apenas se está iniciando.Neuronal communication in the nervous system is mediated, in the vast majority of animals, by chemical synaptic transmission. In most cases this junctional communication occurs via the release of a transmitter substance, from a presynaptic nerve terminal. This synaptic transmitter binds post-synaptic receptors and results in a postsynaptic response on the target cell. Such release of transmitter from the presynaptic terminal appears to be universally triggered by a transient increase of intracellular calcium at the release site. This transient increase in calcium, is mostly brought about by the activation of voltage gated calcium channels (VGCC) which result in a Ca2+ influx into the presynaptic cytosol that triggers synaptic vesicle fusion and neurotransmitter release. Methodology: Databases such as Medline, Pubmed and Columbia University Library ejournals were consulted, in order to find articles published from January 1990 to November 2004. Conclusions: During the last decade significant advances have been achieved in the molecular and genetics of voltage gated channels. The integration of this knowledge with functional neurophysiology and clinical neurology is only starting

Constraints on Supersymmetric Theories from μ→e,γ\mu\to e,\gamma

In the absence of any additional assumption it is natural to conjecture that sizeable flavour-mixing mass entries, $\Delta m^2$, may appear in the mass matrices of the scalars of the MSSM, i.e. $\Delta m^2\sim O(m^2)$. This flavour violation can still be reconciled with the experiment if the gaugino mass, $M_{1/2}$, is large enough, leading to a {\em gaugino dominance} framework (i.e. $M_{1/2}^2\gg m^2$), which permits a remarkably model--independent analysis. We study this possibility focussing our attention on the $\mu\rightarrow e,\gamma$ decay. In this way we obtain very strong and general constraints, in particular \frac{M_{1/2}^2}{\Delta m}\simgt 34\ {\rm TeV}. On the other hand, we show that our analysis and results remain valid for values of $m^2$ much larger than $\Delta m^2$, namely for \frac{\Delta m^2}{m^2}\simgt \frac{m^2} {10\ {\rm TeV^2}}, thus extending enormously their scope of application. Finally, we discuss the implications for superstring scenarios.Comment: 12 pages, Latex, 5 figures as uuencoded compressed postscript files, uses psfig.st

Domain walls in supersymmetric QCD: from weak to strong coupling

We consider domain walls that appear in supersymmetric QCD with Nf < Nc massive flavours. In particular, for 2 Nf < Nc we explicitly construct the domain walls that interpolate between vacua labeled by i and (i+ N_f). We show that these solutions are Bogomol'nyi-Prasad-Sommerfield (BPS) saturated for any value of the mass of the matter fields. This fact allows us to evaluate the large mass limit of these domain walls. We comment on the relevance of these solutions for supersymmetric gluodynamics.Comment: 4 pages, 4 figures, LaTex, uses psfig.st

Antidepressivos de nova geração na neuropatia diabética dolorosa

La incidencia de neuropatía diabética aumenta con la duración de la diabetes y el grado de hiperglicemia. El dolor es uno de los síntomas más comunes e incapacitantes de la neuropatía diabética y su control farmacológico es complejo. La efectividad de los antidepresivos ha sido descrita en diferentes tipos de dolor neuropático, pero su verdadera efectividad, al ser usados como analgésicos en el dolor en la neuropatía diabética, aún es controvertida. Objetivo: Realizar una revisión sistemática y meta-análisis para determinar el nivel de evidencia en relación con la potencia analgésica de estos nuevos antidepresivos para el manejo del dolor en el paciente con neuropatía diabética dolorosa. Métodos: La búsqueda cubrió las bases de datos Cochrane, MEDLINE, EMBASE y LILACS entre enero de 2000 y agosto de 2007. De cada artículo se obtuvo la siguiente información: criterios para diagnóstico de neuropatía diabética, edad promedio de los pacientes, antidepresivo recibido y dosis, tamaño de la muestra, duración de la enfermedad, seguimiento del tratamiento, medidas de desenlace, evaluación del dolor y medicación de rescate. Resultados: Se obtuvo un RR combinado de 1,67 (IC 95% 1,38 - 2,02). El NNT correspondiente para la Duloxetina fue de 6 (95% CI 5- 8), para obtener una analgesia superior a 50% en pacientes con dolor por neuropatía diabética. Discusión: Se ha demostrado que los antidepresivos son empleados con frecuencia y efectivos como analgésicos para el dolor por neuropatía diabética.The incidence of diabetic neuropathy increases with the duration of diabetes and the degree of hyperglycaemia. Pain is one of the most common and incapacitating symptoms of diabetic neuropathy and its pharmacological control is complex. The effectiveness of antidepressive agents has been described in different types of neuropathic pain, but their effectiveness, when used as analgesics in painful diabetic neuropathy, still remains controversial. Objective: To review the possible role of new-generation antidepressive agents in the treatment of pain in diabetic peripheral neuropathy. This work has thus consisted of a meta-analysis for determining which antidepressive agent had the best analgesic potential in managing pain in patients suffering from painful diabetic neuropathy. Methods: This search covered the Cochrane, MEDLINE, EMBASE and LILACS databases, between January 2000 and August 2007. The following information was obtained from each article: criteria for diagnosing diabetic neuropathy, patients' age average, antidepressant drug received and dose, sample size, duration of the disease and treatment follow-up, outcome measurement, evaluation of pain and rescue medication. Results: A combined RR: 1.67 (95% CI 1.38 - 2.02) was obtained; this result indicated that the antidepressive agent duloxetine, was effective for controlling pain in diabetic neuropathy. The corresponding NNT for Duloxetine was established, according to our interests; NNT = 6 (95% CI 5- 8) for achieving greater than 50% analgesia in patients suffering from painful diabetic neuropathy. Discussion: Antidepressive agents are frequently employed in the specific case of diabetic neuropathy; their analgesic benefit has been demonstrated.A incidência de neuropatia diabética aumenta com a duração da diabetes e o grau de hiperglicemia. A dor é um dos sintomas mais comuns e incapacitantes da neuropatia diabética e seu controle farmacológico é complexo. A efetividade dos antidepressivos tem sido descrita em diferentes tipos de dor neuropática, mas sua verdadeira efetividade, quando utilizados como analgésicos na dor na neuropatia diabética, ainda é controvertida. Objetivo: realizar uma revisão sistemática e meta-análise para determinar o nível de evidencia em relação com a potência analgésica destes novos antidepresivos para o manejo da dor no paciente com neuropatia diabética dolorosa. Métodos: A procura cobriu as bases de dados Cochrane, MEDLINE, EMBASE e LILACS entre janeiro de 2000 e agosto de 2007. De cada artigo se obteve a seguinte informação: critérios para diagnóstico de neuropatia diabética, idade em media dos pacientes, antidepressivo recebido e dose, tamanho da amostra, duração da enfermidade, seguimento do tratamento, medidas de desenlace, avaliação da dor e medicação de resgate. Resultados: obteve-se um RR combinado de 1,67 (IC 95% 1,38 - 2,02). O NNT correspondente  para a Duloxetina foi de 6 (95% CI 5- 8), para obter uma analgesia superior a 50% em pacientes com dor por neuropatia diabética. Discussão: tem se demonstrado que os antidepressivos são empregados com freqüência e efetivos como analgésicos para a dor por neuropatia diabética

Agricultural productivity in past societies: toward an empirically informed model for testing cultural evolutionary hypotheses

Agricultural productivity, and its variation in space and time, plays a fundamental role in many theories of human social evolution. However, we often lack systematic information about the productivity of past agricultural systems on a scale large enough to test these theories properly. The effect of climate on crop yields has received a great deal of attention resulting in a range of empirical and process-based models, yet the focus has primarily been on current or future conditions. In this paper, we argue for a “bottom-up” approach that estimates potential productivity based on information about the agricultural practices and technologies used in past societies. Of key theoretical interest is using this information to estimate the carrying high quality historical and archaeological information about past societies in order to infer the temporal and geographic patterns of change in agricultural productivity and potential. We discuss information we need to collect about past agricultural techniques and practices, and introduce a new databank initiative that we have developed for collating the best available historical and archaeological evidence. A key benefit of our approach lies in making explicit the steps in the estimation of past productivities and carrying capacities, and in being able to assess the effects of different modelling assumptions. This is undoubtedly an ambitious task, yet promises to provide important insights into fundamental aspects of past societies, enabling us to test more rigorously key hypotheses about human socio-cultural evolution