Modeling the galactic diffuse gamma-ray emission

The diffuse gamma-ray emission in our Galaxy is produced by highly energetic electrons interacting mainly with radiation fields through inverse Compton scattering or in interactions with interstellar matter through Bremsstrahlung. Furthermore, protons also interact with the interstellar matter and produce gamma-rays through the production of pion particles and their subsequent decay. The energy range of gamma-ray emission covers the domain from a few MeV (1 MeV = 106 eV) up to energies > 100 TeV (1 TeV = 1012 eV). In this work a model to predict the diffuse gamma-ray emission is presented. The general idea of this model is to simulate a population of galactic sources, which accelerate protons and electrons, distributed according to the populations of supernova remnants and pulsars at radio wavelengths. Through the previously mentioned interaction processes, the diffuse gamma-ray emission spectrum can be predicted for different regions of the Galaxy. The goal of this thesis is to produce the spectrum of diffuse gamma-ray emission for the two different regions of the Galaxy at l=344 longitude, b=0 latitude and at l=344 longitude, b=4 latitude

Capillary-Wave Model for the Solidification of Dilute Binary Alloys

Starting from a phase-field description of the isothermal solidification of a dilute binary alloy, we establish a model where capillary waves of the solidification front interact with the diffusive concentration field of the solute. The model does not rely on the sharp-interface assumption, and includes non-equilibrium effects, relevant in the rapid-growth regime. In many applications it can be evaluated analytically, culminating in the appearance of an instability which, interfering with the Mullins-Sekerka instability, is similar to that, found by Cahn in grain-boundary motion.Comment: 17 pages, 12 figure

All-cause mortality following a cancer diagnosis amongst multiple sclerosis patients: A Swedish population-based cohort study

Background and purpose: A reduced cancer risk amongst patients with multiple sclerosis (MS) has been reported. Theoretically, this could represent a genuine reduction in risk or, alternatively, 'diagnostic neglect', where cancer is undiagnosed when symptoms are misattributed to MS. Objective: Assess all-cause mortality risk following a cancer diagnosis in patients with MS compared with a cohort without MS. Patients: A cohort of MS patients (n = 19 364) and a cohort of the general population (n = 192 519) were extracted from national Swedish registers from 1969 to 2005. All-cause mortality after cancer in MS was compared with the general population. Poisson regression analysis was conducted in the MS and non-MS cohorts separately. The models were adjusted for follow-up duration, year at entry, sex, region and socioeconomic index. The two cohorts were combined and differences in mortality risk were assessed using interaction testing. Results: The adjusted relative risk (and 95 confidence interval) for all-cause mortality following a cancer diagnosis in MS patients (compared with MS patients without cancer) is 3.06 (2.86-3.27; n = 1768) and amongst those without MS 5.73 (5.62-5.85; n = 24 965). This lower magnitude mortality risk in the MS patients was confirmed by multiplicative interaction testing (P < 0.001). Conclusions: A consistent pattern of lower magnitude of all-cause mortality risk following cancer in MS patients for a range of organ-specific cancer types was found. It suggests that cancer diagnoses tend not to be delayed in MS and diagnostic neglect is unlikely to account for the reduced cancer risk associated with MS. The lower magnitude cancer risk in MS may be due to disease-associated characteristics or exposures. © 2015 EAN

The role and therapeutic targeting of α-, β- and γ-secretase in Alzheimer's disease

Alzheimer's disease (AD) is the most common form of dementia in the elderly and its prevalence is set to increase rapidly in coming decades. However, there are as yet no available drugs that can halt or even stabilize disease progression. One of the main pathological features of AD is the presence in the brain of senile plaques mainly composed of aggregated β amyloid (Aβ), a derivative of the longer amyloid precursor protein (APP). The amyloid hypothesis proposes that the accumulation of Aβ within neural tissue is the initial event that triggers the disease. Here we review research efforts that have attempted to inhibit the generation of the Aβ peptide through modulation of the activity of the proteolytic secretases that act on APP and discuss whether this is a viable therapeutic strategy for treating AD.&lt;p&gt;&lt;/p&gt; Alzheimer's disease (AD) is the most common form of dementia in the elderly but as yet there are no drugs that can halt the progression of this disease. In a theory called the ‘amyloid hypothesis’, researchers have proposed that the accumulation of a small protein fragment called beta amyloid or Aβ within brain tissue is the event which triggers Alzheimer's disease. Aβ is a derivative of the longer amyloid precursor protein (APP). Here we review research efforts that have attempted to inhibit the generation of Aβ through modulation of proteins called secretases which cut APP into Aβ. Author edits made on: 20 May 2015

La praxis pedagógica

La Pedagogía puede considerarse praxis tanto en su vertiente teórica como práctica. La Pedagogía "teórica" debe revalorizarse en términos de praxis. No sólo explicativa o interpretativa, también transformativa, mediadora entre otras prácticas educativas. Pero en esta ponencia queremos referirnos a la Pedagogía en su vertiente práctica, cuando es práctica y no sólo pensamiento. La Pedagogía como práctica es interacción intersubjetiva, deliberativa, argumentativa, imbuída o informada éticamente, que requiere de variados "saber hacer" (savoir faire), que en el sentido aristotélico es a la vez praxis (relación entre sujetos) y poiesis (relación de los sujetos con objetos). Interacción incluida y atravesada por la realidad social, que también es práctica social subjetiva objetivada, condicionante, como alienante o liberadora. Nos preguntamos en qué consiste su especificidad, y cuáles son sus nexos con otras prácticas educativas. Sabemos que a diferencia del momento reflexivo con énfasis analítico, la praxis demanda una mirada sintética, orientada a la acción; y a diferencia de limitarse al conocimiento de la realidad, requiere de la utopía; conlleva un carácter propositivo, una elección de valores ético políticos, una construcción de sentidos culturales, que trascienden la descripción y la explicación. Referirse a la Pedagogía requiere una distinción reflexiva entre "lo pedagógico" -que trata sobre la educación- y "lo didáctico" -que trata sobre la enseñanza. Reconocemos que no puede haber educación sin enseñanza, pero también que la enseñanza no agota la educación. Temas como ciudadanía, género, violencia, trabajo, no se resuelven dictando clases o desarrollando unidades didácticas particulares. La Pedagogía y la intervención pedagógica abordan la participación de diversos actores educacionales, no limitados a los enseñantes; toman decisiones acerca de relevancias temáticas, previas al planeamiento didáctico; trabajan sobre los ámbitos institucionales, no sólo en el análisis sino en la intervención guiada por valores. Específicamente, la Pedagogía recupera las nociones de formación y humanismo, implícitas en la propuesta del "Bildung"

The business value of appearing on The New York Times

More press coverage creates better managed, more profitable firms – and an opportunity for investors, write Michael Ungeheuer and Alexander Hiller

Computational Thermodynamics and Kinetics in Materials Modelling and Simulations

Over the past two decades, Computational Thermodynamics and Kinetics have been tremendously contributed to materials modeling and simulations and the demands on quantitative conceptual design and processing of various advanced materials arisen from various industries and academic institutions involved in materials manufacturing, engineering and applications are still rapidly increasing