Stability behaviour of composite magnetorheological fluids by an induction method

Este artículo puede consultarse en la siguiente dirección de la editorial: http://jim.sagepub.com/content/early/2015/03/26/1045389X15577656.full.pdf+htmlIn this work we study the stability behaviour of composite magnetorheological (MR) fluids consisting of magnetic (iron) and non-magnetic (poly (methylmethacrylate), PMMA) particles dispersed in mineral oil. Because of the opacity of the suspensions, optical methods traditionally employed for evaluation of the gravitational settling in colloidal suspensions are not suitable for sedimentation follow-up in this case. For this reason, we use an alternative method based on the evaluation of the resonant frequency of the inductance of a thin coil surrounding the sample The movement of the coil along the height of the container at specified steps and time intervals allows obtaining information about the local volume fraction of particles inside the tube. The obtained successive profiles for the multi-component suspensions show a decrease of the iron particle settling and of the initial rate of settling as the PMMA volume fraction is increased. Finally, the increase of the PMMA concentration gives rise to an improvement of the rheological properties upon magnetic field application for a given concentration of iron. Both a strongrheological response and a good colloidal stability are essential for practical applications.Proyectos PE2012-FQM694 (Junta de Andalucía, Spain)y FIS2013-47666-C3-1-R (Ministerio de Economía y Competitividad, Spain). L. R.-A. agrradece a la Universidad de Granada su contrato puente (Plan Propio de Investigación, UGR)

Análisis e inteligencia de negocios con evaluación de indicadores claves de desempeño

This article describes how business analytics and intelligence tools contribute to business performance by setting key performance indicators (KPIs) with tightened measurement slices for greater accuracy by forming part of the core of a balanced scorecard, To clarify the organizational objectives prior to conducting a local survey of high confidence. This benefits in the effectiveness of its application if it focuses on the development of new alternatives with differentiated and innovative services, increasing the satisfaction of all those involved. For this we inquired into 81 small and medium level companies in which it was necessary to determine the representative dimensions of study, from this we obtained the following KPIs to evaluate; Distribution of customers, sales force, rate of consumption of products more and less sold, customer satisfaction, products harmful to the environment, to cite the most significant, and represents how to measure some of them.En este artículo se describe cómo las herramientas de análisis e inteligencia de negocios aportan al rendimiento empresarial a través de fijar los indicadores claves de desempeño (KPI) con cortes de medición ajustados para una mayor precisión formando parte del núcleo de un cuadro de mando integral, para aclarar los objetivos organizacionales previa realización de un sondeo local de alta confianza. Esto beneficia en la efectividad de su aplicación si se enfoca al desarrollo de nuevas alternativas con servicios diferenciados e innovadores, aumentando la satisfacción de todos los involucrados. Para esto se indagó en 81 empresas pequeñas y de nivel medio en las cuales fue necesario determinar las dimensiones representativas de estudio, a partir de esto se obtuvo los siguientes KPIS para evaluar; distribución geográfica de clientes, fuerza de ventas, tasa de consumo de productos más y menos vendidos, satisfacción de clientes, productos nocivos para el medio ambiente, por citar los más significativos, y se representa cómo medir algunos de ellos

Exploratory analysis of power spectrum and functional connectivity during resting state in young binge drinkers: A MEG study

© Electronic version of an article published as International Journal of Neural Systems, Volume 25, Issue 03, May 2015, 13 Pages (https://doi.org/10.1142/S0129065715500082)Binge Drinking (BD) is a pattern of intermittent intensive alcohol intake which has spread among young adults over the last decades. Adolescence constitutes a critical neuromaturation period in which the brain is particularly sensitive to the effects of alcohol. However, little is known about how BD affects the brain activity. This study aimed to characterize the brain's functional organization in BD and non-BD young population by means of analyzing functional connectivity (FC) and relative power spectra (PS) profiles measured with magnetoencephalography (MEG) during eyes-closed resting state. Our sample composed 73 first-year university students (35 BDs and 38 controls). Results showed that the BD subjects displayed a decreased alpha FC in frontal-parietal regions, and conversely, an enhanced FC in the delta, theta and beta bands in fronto-temporal networks. Besides the FC differences, the BD group showed a decreased PS within alpha range and an increased PS within theta range in the brain's occipital region. These differences in FC and PS measurements provide new evidence of the neurophysiological alterations related to the alcohol neurotoxicity and could represent an initial sign of an anomalous neural activity caused by a BD pattern of alcohol consumption during youthThis study was supported by the project SPI/2010/134 and SPI/2010/051, from the Spanish Ministry of Health and Social Politics (National Plan on Drugs), and two predoctoral fellowships from the Ministry of Education (FPI, BES-2010-036469 and FPU, AP2008-03433)S

Diseño conceptual de un dispositivo de compresión de barra de Hopkinson

Este trabajo expone la metodología seguida y la revisión bibliográfica necesaria para el diseño conceptual de una barra de Hopkinson de compresión, en donde se revisarán los aspectos y componentes más importantes de este dispositivo, así como los materiales elegidos para su construcción y su futura puesta en marcha, a fin de poder caracterizar dinámicamente probetas de materiales de baja impedancia mecánica.Palabra(s) Clave(s): Alta tasa de deformación, barra de Hopkinson, impedancia mecánica, propagación unidimensional

HERC1 ubiquitin ligase is required for hippocampal learning and memory

Mutations in the human HERC1 E3 ubiquitin ligase protein develop intellectual disability. The tambaleante (tbl) mouse carries a HERC1 mutation characterized by cerebellar ataxia due of adult cerebellar Purkinje cells death by extensive autophagy. Our previous studies demonstrated that both the neuromuscular junction and the peripheral nerve myelin sheaths are also affected in this mutant. Moreover, there are signs of dysregulated autophagy in the central nervous system in the tbl mouse, affecting spinal cord motor neurons, and pyramidal neurons of the neocortex and the hippocampal CA3 region. The tbl mutation affects associative learning, with absence of short- and long-term potentiation in the lateral amygdala, altered spinogenesis in their neurons, and a dramatic decrease in their glutamatergic input. To assess whether other brain areas engaged in learning processes might be affected by the tbl mutation, we have studied the tbl hippocampus using behavioral tests, ex vivo electrophysiological recordings, immunohistochemistry, the Golgi-Cox method and transmission electron microscopy. The tbl mice performed poorly in the novel-object recognition, T-maze and Morris water maze tests. In addition, there was a decrease in glutamatergic input while the GABAergic one remains unaltered in the hippocampal CA1 region of tbl mice, accompanied by changes in the dendritic spines, and signs of cellular damage. Moreover, the proportions of immature and mature neurons in the dentate gyrus of the tbl hippocampus differ relative to the control mice. Together, these observations demonstrate the important role of HERC1 in regulating synaptic activity during learning

Drainage of the hepatic cyst by laparoscopy - clinical case

Liver cysts are formations of serous content surrounded by normal liver parenchyma, without communication with the bile duct. The cyst wall is generally lined with cuboidal epithelium surrounded by layers of connective tissue. They are rare entities in adult patients, generally, they are asymptomatic in 3%, and between 10-15% of all patients will generate symptoms that lead them to consult. A 38-year-old man with an external abdominal tomography study that reported a giant hepatic cyst. Laboratory blood tests: hemoglobin 7.9 g/dl; leukocytosis 11,000/ul; serum electrolytes, liver transaminases, and bilirubin were normal, alkaline phosphatase, and gamma glutamyl-transpeptidase 94 U/l and 241 U/l, respectively. Non-reactive anti-human immuno-deficiency virus (HIV 1) and two antibodies, venereal disease research laboratory (VDRL), cancer antigen (CA) 19-9 antigen, hepatitis B-C surface antigen, and carcinoembryonic antigen were negative. He underwent surgery by laparoscopic drainage of the liver cyst, through a median infraumbilical incision with the Hasson technique and placement of three 12 mm trocars, hepatomegaly was observed without finding an exit site for purulent material, it was punctured through liver segment V, and 2000 ml of citrine fluid was extracted. The hepatic wound is addressed with a 1-0 caliber chromic catgut thread, placing a Penrose-type drain. At 48 hours postoperatively, it evolves favorably, so it is decided to discharge. Hepatic cysts are fluid-filled cavities lined by a single-layered cuboidal or columnar biliary epithelium in the liver. A majority of hepatic cysts are found incidentally on liver imaging, such as abdominal ultrasonography, computed tomography, or magnetic resonance imaging

Functional and structural brain connectivity of young binge drinkers: a follow-up study

Adolescence is a period of ongoing brain maturation characterized by hierarchical changes in the functional and structural networks. For this reason, the young brain is particularly vulnerable to the toxic effects of alcohol. Nowadays, binge drinking is a pattern of alcohol consumption increasingly prevalent among adolescents. The aim of the present study is to evaluate the evolution of the functional and anatomical connectivity of the Default Mode Network (DMN) in young binge drinkers along two years. Magnetoencephalography signal during eyes closed resting state as well as Diffusion Tensor Imaging (DTI) were acquired twice within a 2-year interval from 39 undergraduate students (22 controls, 17 binge drinkers) with neither personal nor family history of alcoholism. The group comparison showed that, after maintaining a binge drinking pattern along at least two years, binge drinkers displayed an increased brain connectivity of the DMN in comparison with the control group. On the other hand, the structural connectivity did not show significant differences neither between groups nor over the time. These findings point out that a continued pattern of binge drinking leads to functional alterations in the normal brain maturation process, even before anatomical changes can be detected.This study was supported by the projects SPI/2010 and SPI/2010/051 from Spanish Ministry of Health and Social Politics (National Plan on Drugs). Funding was also provided from the SFRH/BPD/109750/2015 Postdoctoral Fellowship of the Portuguese Foundation for Science and Technology as well as the Research Center on Psychology (UID/PSI/01662/2013)S