Efficient memory management in video on demand servers

In this article we present, analyse and evaluate a new memory management technique for video-on-demand servers. Our proposal, Memory Reservation Per Storage Device (MRPSD), relies on the allocation of a fixed, small number of memory buffers per storage device. Selecting adequate scheduling algorithms, information storage strategies and admission control mechanisms, we demonstrate that MRPSD is suited for the deterministic service of variable bit rate streams to intolerant clients. MRPSD allows large memory savings compared to traditional memory management techniques, based on the allocation of a certain amount of memory per client served, without a significant performance penaltyPublicad

Exciton condensates in semiconductor quantum wells emit coherent light

We show that a quasi-two dimensional condensate of optically active excitons emits coherent light even in the absence of population inversion. This allows an unambiguous and clear experimental detection of the condensed phase. We prove that, due to the exciton-photon coupling, quantum and thermal fluctuations do not destroy condensation at finite temperature. Suitable conditions to achieve condensation are temperatures of a few K for typical exciton densities, and the use of a pulsed, and preferably circularly polarized, laser.Comment: 5 pages, no figure

Electric-Field Tuning of Spin-Dependent Exciton-Exciton Interactions in Coupled Quantum Wells

We have shown experimentally that an electric field decreases the energy separation between the two components of a dense spin-polarized exciton gas in a coupled double quantum well, from a maximum splitting of $\sim 4$ meV to zero, at a field of $\sim$35 kV/cm. This decrease, due to the field-induced deformation of the exciton wavefunction, is explained by an existing calculation of the change in the spin-dependent exciton-exciton interaction with the electron-hole separation. However, a new theory that considers the modification of screening with that separation is needed to account for the observed dependence on excitation power of the individual energies of the two exciton components.Comment: 5 pages, 4 eps figures, RevTeX, Physical Review Letters (in press

Inflamación muscular: etiología, tratamientos, prevención y poblaciones susceptibles = Muscle inflammation, Etiology, Treatment, Prevention and susceptible Population

La inflamación muscular es la reacción inmediata o retardada de los músculos del cuerpo ante determinados factores que afectan y alteran la homeostasis. Se puede producir como respuesta a algún tipo de lesión muscular, o al ejercicio físico. En la inflamación muscular, es fundamental destacar el papel de un grupo de proteínas llamadas citoquinas que regulan los procesos inflamatorios e inmunológicos implicados en la reparación del tejido dañado. Las adipocinas están entre las citoquinas relacionadas con la obesidad que promueven la inflamación muscular y la IL- 6 provoca una reducción del rendimiento físico con la edad. El uso de los antiinflamatorios no esteroideos (NSAID) permite reducir dicha inflamación durante los primeros días después de que esta aparezca. La administración de inmunomoduladores previene y aminora la inflamación muscular. Otras formas de tratar la inflamación muscular podrían ser el uso de estrógenos o la suplementación por medio de polifenoles, antioxidantes, que pueden beneficiar el rendimiento. Las células madre presentes en los tejidos lesionados, tienen capacidad regenerativa. Por último, hay que destacar el papel de tratamientos locales: crioterapia, RICE, masajes, vibración, ultrasonidos, y la fisioterapia, que han demostrado su utilidad para la reducción de la inflamación muscular, en especial el uso del RICE

Human exceptional longevity: transcriptome from centenarians is distinct from septuagenarians and reveals a role of Bcl-xL in successful aging

24 páginas, 7 figuras. Borras C, et al. Human exceptional longevity: transcriptome from centenarians is distinct from septuagenarians and reveals a role of Bcl-xL in successful aging. Aging (Albany NY). 2016 Oct 28;8(12):3185-3208. doi: 10.18632/aging.101078.Centenarians not only enjoy an extraordinary aging, but also show a compression of morbidity. Using functional transcriptomic analysis of peripheral blood mononuclear cells (PMBC) we identified 1721 mRNAs differentially expressed by centenarians when compared with septuagenarians and young people. Sub-network analysis led us to identify Bcl-xL as an important gene up-regulated in centenarians. It is involved in the control of apoptosis, cellular damage protection and also in modulation of immune response, all associated to healthy aging. Indeed, centenarians display lower plasma cytochrome C levels, higher mitochondrial membrane potential and also less cellular damage accumulation than septuagenarians. Leukocyte chemotaxis and NK cell activity are significantly impaired in septuagenarians compared with young people whereas centenarians maintain them. To further ascertain the functional role of Bcl-xL in cellular aging, we found that lymphocytes from septuagenarians transduced with Bcl-xL display a reduction in senescent-related markers. Finally, to demonstrate the role of Bcl-xL in longevity at the organism level, C. elegans bearing a gain of function mutation in the Bcl-xL ortholog ced-9, showed a significant increase in mean and maximal life span. These results show that mRNA expression in centenarians is unique and reveals that Bcl-xL plays an important role in exceptional aging.This work was supported by grants SAF2013-44663-R, from the Spanish Ministry of Education and Science (MEC); ISCIII2012-RED-43-029 from the “Red Tematica de investigacion cooperative en envejecimiento y fragilidad” (RETICEF); PROMETEOII/2014/056 from "Conselleria d’Educació, Cultura I Esport de la Generalitat Valenciana"; and EU Funded CM1001 and FRAILOMIC-HEALTH.2012.2.1.1-2 (To J.V) APM-03/15 from Conselleria de Sanitat, AICO/2016/067 and from Conselleria d’Educació, Cultura i Esport de la Generalitat Valenciana, Intramural Grant from INCLIVA (to C.B.),VAL i+d Fellowship from Generalitat Valenciana (to C.L.-F.) and Marie Curie Career Integration Grant (to N.F). This study has been co-financed by FEDER funds from the European Union.Peer reviewe

Actividad antioxidante y antimicrobial de los volátiles de cuatro variedades de albahacas cultivadas en el departamento del Tolima

Se determinó la actividad antioxidante de los hidrodestilados de cuatro variedades de Ocimum colectadas en Ibagué, evaluando su capacidad atrapadora del radical DPPH (CARL) y el poder inhibitorio de peroxidación lipídica. Bioprospección de estos extractos naturales de la región se aumentó evaluando su potencial antimicrobial frente a bacterias gram positivas, gram negativas y una levadura. Todos los aceites esenciales mostraron fuerte actividad antioxidante (CARL) comparable a la del tocoferol y actividad antimicrobial frente a Candida albicans, principalmente de las albahacas crespa morada y canela.The antioxidant activity of the hydrodistilleds of four Ocimum varieties growing in Ibagué, was determined by means of both, DPPH radical scavenging activity (FRSA) and inhibition of lipid peroxidation, methods. Bioprospection research with regard these regional natural extracts was increased through the evaluation of the antimicrobial potential against Gram positives,Gram negatives bacteria and a yeast. All the essential oils showed strong antioxidant activity (FRSA) comparable with that of ¿-tocopherol and antimicrobial activity against Candida albicans, mainly exhibited by purple rufle and cinnamon basils

Spin splitting in a polarized quasi-two-dimensional exciton gas

We have observed a large spin splitting between "spin" $+1$ and $-1$ heavy-hole excitons, having unbalanced populations, in undoped GaAs/AlAs quantum wells in the absence of any external magnetic field. Time-resolved photoluminescence spectroscopy, under excitation with circularly polarized light, reveals that, for high excitonic density and short times after the pulsed excitation, the emission from majority excitons lies above that of minority ones. The amount of the splitting, which can be as large as 50% of the binding energy, increases with excitonic density and presents a time evolution closely connected with the degree of polarization of the luminescence. Our results are interpreted on the light of a recently developed model, which shows that, while intra-excitonic exchange interaction is responsible for the spin relaxation processes, exciton-exciton interaction produces a breaking of the spin degeneracy in two-dimensional semiconductors.Comment: Revtex, four pages; four figures, postscript file Accepted for publication in Physical Review B (Rapid Commun.

New Spanish Cinema: cine, cine, cine, más cine, porfavor

Cambio, nuevas narrativas, nuevas fórmulas de financiación, bajo presupuesto, son las referencias habituales cuando hablamos del cine español más joven y actual. Junto a un momento de dificultad creciente en la financiación de las películas, tenemos también un momento creativo en expansión. Hemos asistido también a un cambio tecnológico y a una forma de demanda distinta por parte del público. ¿Es posible encontrar un modelo que permita el retorno económico suficiente para poder seguir disfrutando del cine?Change, new fiction, new methods of financing, low cost, are the usual cinema references when we talk about young and contemporary Spanish Cinema. Beside a time of increasing difficulty in financing films, we are experiencing a burst of creativity. We have also witnessed a technological change and a different public demand. Is it possible to find a model to enable sufficient economic return to continue enjoying movies

Blood DNA Methylation Patterns in Older Adults With Evolving Dementia

Dementia and cognitive disorders are major aging-associated pathologies. The prevalence and severity of these conditions are influenced by both genetic and environmental factors. Reflecting this, epigenetic alterations have been associated with each of these processes, especially at the level of DNA methylation, and such changes may help explain the observed interindividual variability in the development of the 2 pathologies. However, the importance of epigenetic alterations in explaining their etiology is unclear because little is known about the timing of when they appear. Here, using Illumina MethylationEPIC arrays, we have longitudinally analyzed the peripheral blood methylomes of cognitively healthy older adults (>70 year), some of whom went on to develop dementia while others stayed healthy. We have characterized 34 individuals at the prediagnosis stage and at a 4-year follow-up in the postdiagnosis stage (total n = 68). Our results show multiple DNA methylation alterations linked to dementia status, particularly at the level of differentially methylated regions. These loci are associated with several dementia-related genes, including PON1, AP2A2, MAGI2, POT1, ITGAX, PACSIN1, SLC2A8, and EIF4E. We also provide validation of the previously reported epigenetic alteration of HOXB6 and PM20D1. Importantly, we show that most of these regions are already altered in the prediagnosis stage of individuals who go on to develop dementia. In conclusion, our observations suggest that dementia-associated epigenetic patterns that have specific biological features are already present before diagnosis, and thus may be important in the design of epigenetic biomarkers for disease detection based on peripheral tissues.This work was supported by: the Spanish Association Against Cancer (grant number PROYE18061FERN to M.F.F.), the Asturias Government (PCTI) cofunding 2018-2022/FEDER (grant number IDI/2018/146 to M.F.F.), the Fundación General CSIC (grant number 0348_CIE_6_E to M.F.F.) and the Health Institute Carlos III (Plan Nacional de I + D + I) cofunding FEDER (grant numbers PI15/00892, PI18/01527 to M.F.F. and A.F.F.). JRT is supported by a Juan de la Cierva fellowship from the Spanish Ministry of Science and Innovation (grant number FJCI-2015-26965). R.F.P. is supported by the Severo Ochoa program (grant number BP17-114). We also acknowledge support from the Institute of Oncology of Asturias (IUOPA, supported by Obra Social Cajastur Liberbank, Spain), the Health Research Institute of Asturias (ISPA-FINBA) and Consorcio Centro de Investigación Biomédica en Red (CIBERER-ISCIII).S

Spin degree of freedom in two dimensional exciton condensates

We present a theoretical analysis of a spin-dependent multicomponent condensate in two dimensions. The case of a condensate of resonantly photoexcited excitons having two different spin orientations is studied in detail. The energy and the chemical potentials of this system depend strongly on the spin polarization . When electrons and holes are located in two different planes, the condensate can be either totally spin polarized or spin unpolarized, a property that is measurable. The phase diagram in terms of the total density and electron-hole separation is discussed.Comment: 4 pages, 3 figures, Accepted for publication in Physical Review Letter