1,644 research outputs found

    Dynamical properties of model communication networks

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    We study the dynamical properties of a collection of models for communication processes, characterized by a single parameter ξ\xi representing the relation between information load of the nodes and its ability to deliver this information. The critical transition to congestion reported so far occurs only for ξ=1\xi=1. This case is well analyzed for different network topologies. We focus of the properties of the order parameter, the susceptibility and the time correlations when approaching the critical point. For ξ<1\xi<1 no transition to congestion is observed but it remains a cross-over from a low-density to a high-density state. For ξ>1\xi>1 the transition to congestion is discontinuous and congestion nuclei arise.Comment: 8 pages, 8 figure

    Linda Collazo: A Bronx Aria

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    This video project follows Linda Collazo, a mezzo-soprano from the Bronx, as she prepares for various performances during fall of 2018. She describes the training in vocals, music, and acting she undergoes in order to break into the highly competitive field of operatic singers. https://giraltjschool.exposure.co/linda-collazo-a-bronx-ari

    «Les branques entrellaçades»: un motiu del folklore verbal i els gèneres mixtos

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    L’article aborda comparativament un motiu de l’art verbal i alhora la seva interacció amb un problema general de l’estudi del folklore: el dels gèneres mixtos i llur significació. El motiu en qüestió és designat «Twining branches» (E631.0.1) en l’índex de Thompson. S’assenyala l’eventual precedent clàssic ovidià i se’n considera la presència en romanços de la tradició romànica peninsular i en balades angloamericanes, gèneres versificats. Si comparteixen el motiu de les branques entrellaçades, difereixen en aspectes funcionals i argumentals. S’aporta una narració oral beduïna del desert Líbic que conté l’argument i el motiu. Aquest text oral és un gènere mixt: hi coexisteixen prosa i vers (prosimetrum). S’analitzen diferències funcionals respecte als textos anteriors i se’n vincula l’especificitat a la naturalesa de l’ordre social en la societat beduïna, a la ideologia que hi és hegemònica, a la identitat ètnica i a la cultura verbal beduïna arabitzada. S’interpreta el gènere mixt en funció de conceptes desenvolupats a partir de la poètica jakobsoniana i, sobretot, en funció del context en què es produeix, això és, de l’especificitat històrica i d’una interpretació èmica, la qual ens permet accedir a la significació que vehicula la juxtaposició de prosa i vers en un context d’actuació específic

    Imbalance of p75(NTR)/TrkB protein expression in Huntington's disease: Implication for neuroprotective therapies

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    Neuroprotective therapies based on brain-derived neurotrophic factor (BDNF) administration have been proposed for Huntington's disease (HD) treatment. However, our group has recently reported reduced levels of TrkB in HD mouse models and HD human brain suggesting that besides a decrease on BDNF levels a reduction of TrkB expression could also contribute to diminished neurotrophic support in HD. BDNF can also bind to p75 neurotrophin receptor (p75(NTR)) modulating TrkB signaling. Therefore, in this study we have analyzed the levels of p75(NTR) in several HD models, as well as in HD human brain. Our data demonstrates a p75(NTR)/TrkB imbalance in the striatum of two different HD mouse models, Hdh(Q111/111) homozygous knockin mice and R6/1 mice that was also manifested in the putamen of HD patients. The imbalance between TrkB and p75(NTR) levels in a HD cellular model did not affect BDNF-mediated TrkB activation of prosurvival pathways but induced activation of apoptotic cascades as demonstrated by increased JNK phosphorylation. Moreover, BDNF failed to protect mutant huntingtin striatal cells transfected with p75(NTR) against NMDA-mediated excitotoxicity, which was associated with decreased Akt phosphorylation. Interestingly, lack of Akt activation following BDNF and NMDA treatment correlated with increased PP1 levels. Accordingly, pharmacological inhibition of PP1 by okadaic acid (OA) prevented mutant huntingtin striatal cell death induced by NMDA and BDNF. Altogether, our findings demonstrate that the p75(NTR)/TrkB imbalance induced by mutant huntingtin in striatal cells associated with the aberrant activity of PP1 disturbs BDNF neuroprotection likely contributing to increasing striatal vulnerability in HD. On the basis of this data we hypothesize that normalization of p75(NTR) and/or TrkB expression or their signaling will improve BDNF neuroprotective therapies in HD. Cell Death and Disease (2013) 4, e595; doi:10.1038/cddis.2013.116; published online 18 April 201

    E2F1, a Novel Regulator of Metabolism.

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    In the past years, several lines of evidence have shown that cell cycle regulatory proteins also can modulate metabolic processes. The transcription factor E2F1 is a central player involved in cell cycle progression, DNA-damage response, and apoptosis. Its crucial role in the control of cell fate has been extensively studied and reviewed before; however, here, we focus on the participation of E2F1 in the regulation of metabolism. We summarize recent findings about the cell cycle-independent roles of E2F1 in various tissues that contribute to global metabolic homeostasis and highlight that E2F1 activity is increased during obesity. Finally, coming back to the pivotal role of E2F1 in cancer development, we discuss how E2F1 links cell cycle progression with different metabolic adaptations required for cell growth and survival

    Poètica, paral·lelisme i sistemes semiòtics paralingüístics

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    Els estudis de Robet Lowth sobre el paral·lelisme en la poesia hebrea no solament van posar en qüestió la perspectiva occidental sobre allò que fa d’un vers un vers, sinó que van promoure’n una perspectiva etnopoètica. En aquest estudi es mostra primerament la naturalesa del paral·lelisme, la seva tipologia, la seva permeabilitat a través de la poesia i la prosa, el llenguatge escrit i l’oral, diversos gèneres verbals i comunicatius fins a la conversa ordinària i no planificada. També s’analitza el problema de la seqüencialitat i la simultaneïtat en el paral·lelisme.Quant al llenguatge i els sistemes semiòtics paralingüístics, se’n presenten i analitzen tres casos distints: 1) La coexistència de llengües on l’una (damin) és parasitària de l’altra (lardil, a l’illa de Mornington, Austràlia). 2) La coexistència d’un llenguatge natural i un sistema de comunicació vocal parasitari: l’espanyol i el xiulet de La Gomera. 3) La coexistència de la llengua tonal dels evuzok (ewondo) i un llenguatge tamborinejat basat en la transmissió dels tons vocàlics dels mots. S’identifiquen les estratègies de desambiguació i es defensa que la relació entre aquests sistemes és analitzable com a paral·lelisme, com ho és la relació entre el nom, la divisa verbal i la divisa tamborinejada ewondo.Robert Lowth’s studies on parallelism in Hebrew poetry not only questioned the Western perspective on what makes a verse a verse, but also led to the adoption of an ethnopoetic perspective. This study first discusses the nature of parallelism, its typology, its pervasiveness through poetry and prose, written and oral language, and a variety of verbal and communicative genres that even include ordinary and unplanned conversation. It also analyses the problem of sequentiality and simultaneity in parallelism. As for language and paralinguistic semiotic systems, three distinct cases are presented and analyzed: 1) The coexistence of languages where one (Damin) is parasitic of the other (Lardil, Monington island, Australia). 2) The coexistence of a natural language and a parasitic vocal communication system: Spanish and the whistled language of La Gomera, Canary Islands. 3) The coexistence of Ewondo, the tonal language of the Evuzok people, and a drumming language based on non-vocal transmission of the vowel tones of the words. Strategies for overcoming ambiguity are identified and it is argued that the relationship between these systems is analytically of a parallelism-like nature, as is the relationship between the name, the verbal motto and the drummed motto of the Evuzok.Els estudis de Robet Lowth sobre el paral·lelisme en la poesia hebrea no solament van posar en qüestió la perspectiva occidental sobre allò que fa d’un vers un vers, sinó que van promoure’n una perspectiva etnopoètica. En aquest estudi es mostra primerament la naturalesa del paral·lelisme, la seva tipologia, la seva permeabilitat a través de la poesia i la prosa, el llenguatge escrit i l’oral, diversos gèneres verbals i comunicatius fins a la conversa ordinària i no planificada. També s’analitza el problema de la seqüencialitat i la simultaneïtat en el paral·lelisme. Quant al llenguatge i els sistemes semiòtics paralingüístics, se’n presenten i analitzen tres casos distints: 1) La coexistència de llengües on l’una (damin) és parasitària de l’altra (lardil, a l’illa de Mornington, Austràlia). 2) La coexistència d’un llenguatge natural i un sistema de comunicació vocal parasitari: l’espanyol i el xiulet de La Gomera. 3) La coexistència de la llengua tonal dels evuzok (ewondo) i un llenguatge tamborinejat basat en la transmissió dels tons vocàlics dels mots. S’identifiquen les estratègies de desambiguació i es defensa que la relació entre aquests sistemes és analitzable com a paral·lelisme, com ho és la relació entre el nom, la divisa verbal i la divisa tamborinejada ewondo

    Índice de Liam: prueba física funcional

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    Made very important test (Liam) in the medical students in Medical Faculty in Artemisa city, because with this examination proof the functional and physical conditions before and after training. All students after training received best results than before. It is very important to because the students obtained some abilities in this subject when will be doctorsSe realizó un análisis de la prueba funcional de Liam en un grupo de estudiantes de 2do año de Medicina de Artemisa con el objetivo de valorar el grado de aptitud cardiovascular y el nivel de entrenamiento de este grupo, donde se obtuvo que la mayoría de los estudiantes el 77,8% estaba apto físicamente y solo dos para un 22,2% se encontraba en la categoría de pobre en la prueba que se realizó al inicio del curso .Esta prueba es de gran utilidad en nuestra formación como futuro Medico Generales Integrales y sobre todo que es muy fácil su proceder y lo podemos aplicar en área de salud con nuestros pacientes ,una vez graduados como médicos .En el mes de Abril después de seis meses de práctica sistemática de ejercicios físicos todos los estudiantes mejoraron de forma considerable su aptitud cardiovascular y el nivel de entrenamiento a las categorías de muy bien y bie

    Factors controlling the geochemical composition of Limnopolar Lake sediments (Byers Peninsula, Livingston Island, South Shetland Island, Antarctica) during the last ca. 1600 years

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    We sampled a short (57 cm) sediment core in Limnopolar Lake (Byers Peninsula, Livingston Island, South Shetland Islands), which spans the last ca. 1600 years. The core was sectioned at high resolution and analyzed for elemental and mineralogical composition, and scanning electron microscope and energy dispersive X-ray spectrometer (SEM-EDS) analysis of glass mineral particles in selected samples. The chemical record was characterized by a contrasted pattern of layers with high Ca, Ti, Zr, and Sr concentrations and layers with higher concentrations of K and Rb. The former were also enriched in plagioclase and, occasionally, in zeolites, while the latter were relatively enriched in 2 : 1 phyllosilicates and quartz. This was interpreted as reflecting the abundance of volcaniclastic material (Ca rich) versus Jurassic–Lower Cretaceous marine sediments (K rich) – the dominant geological material in the lake catchment. SEM-EDS analysis revealed the presence of abundant volcanic shards in the Ca-rich layers, pointing to tephras most probably related to the activity of Deception Island volcano (located 30 km to the SE). The ages of four main peaks of volcanic-rich material (AD ca. 1840–1860 for L1, AD ca. 1570–1650 for L2, AD ca. 1450–1470 for L3, and AD ca. 1300 for L4) matched reasonably well the age of tephra layers (AP1 to AP3) previously identified in lakes of Byers Peninsula. Some of the analyzed metals (Fe, Mn, Cu, and Cr) showed enrichments in the most recent tephra layer (L1), suggesting relative changes in the composition of the tephras as found in previous investigations. No evidence of significant human impact on the cycles of most trace metals (Cu, Zn, Pb) was found, probably due to the remote location of Livingston Island and the modest research infrastructures; local contamination was found by other researchers in soils, waters and marine sediments on areas with large, permanent research stations. Chromium is the only metal showing a steady enrichment in the last 200 years, but this cannot be directly attributed to anthropogenic pollution since recent research supports the interpretation that climatic variability (reduced moisture content and increased wind intensity) may have resulted in enhanced fluxes of mineral dust and trace elements (Cr among them) to Antarctica. At the same time, some features of the chemical record suggest that climate may have also played a role in the cycling of the elements, but further research is needed to identify the underlying mechanisms.This work was partially supported by projects CGL2010-20672 and REN2000-0345-ANT (Spanish Ministerio de Ciencia e Innovación), POL2006-06635/CGL (Spanish Ministerio de Educación y Cultura), and 10PXIB200182PR (Dirección Xeral de I+D, Xunta de Galicia).Peer reviewe
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