787 research outputs found
Understanding the impact of line-of-sight in the ergodic spectral efficiency of cellular networks
In this paper we investigate the impact of lineof-sight (LoS) condition in the ergodic spectral efficiency of cellular networks. To achieve this goal, we have considered the kappa-mu shadowed model, which is a general model that provides an excellent fit to a wide set of propagation conditions. To overcome the mathematical complexity of the analysis, we have split the analysis between large and small-scale effects. Building on the proposed framework, we study a number of scenarios that range from heavily-fluctuating LoS to deterministic-LoS. Finally, we shed light on the interplay between fading severity and spectral efficiency by means of the amount of fading.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Physical Layer Security of Large Reflecting Surface Aided Communications with Phase Errors
The physical layer security (PLS) performance of a wireless communication
link through a large reflecting surface (LRS) with phase errors is analyzed.
Leveraging recent results that express the \ac{LRS}-based composite channel as
an equivalent scalar fading channel, we show that the eavesdropper's link is
Rayleigh distributed and independent of the legitimate link. The different
scaling laws of the legitimate and eavesdroppers signal-to-noise ratios with
the number of reflecting elements, and the reasonably good performance even in
the case of coarse phase quantization, show the great potential of LRS-aided
communications to enhance PLS in practical wireless set-ups.Comment: This work has been submitted to the IEEE for publication. Copyright
may be transferred without notice, after which this version may no longer be
accessibl
Drosophila Imaginal Discs as a Playground for Genetic Analysis: Concepts, Techniques and Expectations for Biomedical Research
Drosophila imaginal discs are epithelial tissues perfectly suited to use them as a playground to define the functional contribution of genes to epithelial development and organ morphogenesis. The more we know about the discs and the mechanisms directing their development, the best prepared we are to assign specific “functions” to individual genes based on phenotypic observations. Conversely, and thinking from the perspective of the gene, the more we know about its function, the best inferences we could make about the mechanisms underlying imaginal disc development. This reciprocal relationship, coupled to the arsenal of possible experimental approaches available in Drosophila genetics, genomics and cellular biology, makes these tissues excellent systems to address biological problems with biomedical relevance. In this review, an overview of three interconnected aspects related to the use of Drosophila imaginal discs as an experimental system to analyze gene function is given: (i) imaginal discs biology, with a focus in the genetic mechanisms involved in pattern formation; (ii) concepts and available experimental tools for the analyses of gene function and (iii) uses of Drosophila and the imaginal discs for addressing biomedical problems
Análisis termodinámico de un chiller de absorción de 1 y 2 etapas de una planta de cogeneración
Thermodynamics models of a single and a non-common double stage ammonia-water absorption chiller that use waste heat (from three reciprocating engines of 8.7 MW each one) are developed to analyze the performance of the chiller for different operative conditions. A comparison of a single stage refrigeration system with the two stages proposed system is performed in this paper. The coefficient of performance (COP) obtained for both systems are the same, but the heat flux removed from the cooling media with the two-stage system increase from 1.3MW (single stage) until 1.6 MW due to the heat recovered increased with the second generator. The heat recovered used by the chiller was 3.8 MW, and the utilization factor of the cogeneration plant was 58.11%, and the cooling capacity of the equipment was 1,623 kW. Finally, the estimated economics savings for electric power due to the implementation of the absorption chiller that uses exhaust gases in place of a common refrigeration system by vapor compression with the same cooling capacity was 142,000.00 USD/year.Se han desarrollado modelos termodinámicos de enfriadores de agua por absorción de una etapa y ciclo no común de dos etapas que usan calor de desecho (de motores de combustión interna de 8,7 MW cada uno) para analizar las condiciones de operación de los equipos. Se ha realizado la comparación del sistema de una etapa con el sistema propuesto (2 etapas) en esta investigación. El coeficiente de desempeño (COP) obtenido para ambos sistemas fue el mismo, pero el calor removido del espacio refrigerado aumento de 1,3 MW (una etapa) a 1,6 MW (dos etapas) debido a que se recupera más energía residual utilizando un segundo generador. El calor residual aprovechado por el equipo de refrigeración fue de 3,8 MW y el factor de planta del proceso de cogeneración fue de 58,11 % y la capacidad de refrigeración del equipo fue de 1,623 kW. Finalmente, los ahorros económicos estimados por concepto de energía eléctrica que se tienen por poner en marcha el sistema de refrigeración por absorción que utiliza gases de escape como fuente de energía en lugar de un equipo común de refrigeración por compresión de la misma capacidad son 142 000,00 USD/año
Genome-wide phenotypic RNAi screen in the Drosophila wing: Global parameters
We have screened a collection of UAS-RNAi lines targeting 10,920 Drosophila protein-coding genes for phenotypes in the adult wing. We identified 3653 genes (33%) whose knockdown causes either larval/pupal lethality or a mutant phenotype affecting the formation of a normal wing. The most frequent phenotypes consist of changes in wing size, vein differentiation, and patterning, defects in the wing margin and in the apposition of the dorsal and ventral wing surfaces. We also defined 16 functional categories encompassing the most relevant aspect of each protein function and assigned each Drosophila gene to one of these functional groups. This allowed us to identify which mutant phenotypes are enriched within each functional group. Finally, we used previously published gene expression datasets to determine which genes are or are not expressed in the wing disc. Integrating expression, phenotypic and molecular information offers considerable precision to identify the relevant genes affecting wing formation and the biological processes regulated by the
Red clover (Trifolium pratense L.) draft genome provides a platform for trait improvement
Red clover (Trifolium pratense L.) is a globally significant forage legume in pastoral livestock
farming systems. It is an attractive component of grassland farming, because of its high yield and
protein content, nutritional value and ability to fix atmospheric nitrogen. Enhancing its role further
in sustainable agriculture requires genetic improvement of persistency, disease resistance, and
tolerance to grazing. To help address these challenges, we have assembled a chromosome-scale
reference genome for red clover. We observed large blocks of conserved synteny with Medicago
truncatula and estimated that the two species diverged ~23 million years ago. Among the 40,868
annotated genes, we identified gene clusters involved in biochemical pathways of importance for
forage quality and livestock nutrition. Genotyping by sequencing of a synthetic population of 86
genotypes show that the number of markers required for genomics-based breeding approaches is
tractable, making red clover a suitable candidate for association studies and genomic selection
Spanish guidelines for the use of targeted deep sequencing in myelodysplastic syndromes and chronic myelomonocytic leukaemia
The landscape of medical sequencing has rapidly changed with the evolution of next generation sequencing (NGS). These technologies have contributed to the molecular characterization of the myelodysplastic syndromes (MDS) and chronic myelomonocytic leukaemia (CMML), through the identification of recurrent gene mutations, which are present in >80% of patients. These mutations contribute to a better classification and risk stratification of the patients. Currently, clinical laboratories include NGS genomic analyses in their routine clinical practice, in an effort to personalize the diagnosis, prognosis and treatment of MDS and CMML. NGS technologies have reduced the cost of large-scale sequencing, but there are additional challenges involving the clinical validation of these technologies, as continuous advances are constantly being made. In this context, it is of major importance to standardize the generation, analysis, clinical interpretation and reporting of NGS data. To that end, the Spanish MDS Group (GESMD) has expanded the present set of guidelines, aiming to establish common quality standards for the adequate implementation of NGS and clinical interpretation of the results, hoping that this effort will ultimately contribute to the benefit of patients with myeloid malignancies
Differences in response to antiretroviral therapy in HIV-positive patients being treated for tuberculosis in Eastern Europe, Western Europe and Latin America.
BACKGROUND: Efavirenz-based antiretroviral therapy (ART) regimens are preferred for treatment of adult HIV-positive patients co-infected with tuberculosis (HIV/TB). Few studies have compared outcomes among HIV/TB patients treated with efavirenz or non-efavirenz containing regimens. METHODS: HIV-positive patients aged ≥16 years with a diagnosis of tuberculosis recruited to the TB:HIV study between Jan 1, 2011, and Dec 31, 2013 in 19 countries in Eastern Europe (EE), Western Europe (WE), and Latin America (LA) who received ART concomitantly with TB treatment were included. Patients either received efavirenz-containing ART starting between 15 days prior to, during, or within 90 days after starting tuberculosis treatment, (efavirenz group), or other ART regimens (non-efavirenz group). Patients who started ART more than 90 days after initiation of TB treatment, or who experienced ART interruption of more than 15 days during TB treatment were excluded. We describe rates and factors associated with death, virological suppression, and loss to follow up at 12 months using univariate, multivariate Cox, and marginal structural models to compare the two groups of patients. RESULTS: Of 965 patients (647 receiving efavirenz-containing ART, and 318 a non-efavirenz regimen) 50% were from EE, 28% from WE, and 22% from LA. Among those not receiving efavirenz-containing ART, regimens mainly contained a ritonavir-boosted protease inhibitor (57%), or raltegravir (22%). At 12 months 1.4% of patients in WE had died, compared to 20% in EE: rates of virological suppression ranged from 21% in EE to 61% in WE. After adjusting for potential confounders, rates of death (adjusted Hazard Ratio; aHR, 95%CI: 1.13, 0.72-1.78), virological suppression (aHR, 95%CI: 0.97, 0.76-1.22), and loss to follow up (aHR, 95%CI: 1.17, 0.81-1.67), were similar in patients treated with efavirenz and non-efavirenz containing ART regimens. CONCLUSION: In this large, prospective cohort, the response to ART varied significantly across geographical regions, whereas the ART regimen (efavirenz or non-efavirenz containing) did not impact on the proportion of patients who were virologically-suppressed, lost to follow up or dead at 12 months
- …