Turbo-Suppression d'interférences dans un système à étalement de spectre utilisant le codage Spatio-Temporel

: On propose dans cet article l'utilisation de codage spatio-temporel pour accroître la capacité d'un système à étalement de spectre et pour aider à la suppression des interférences d'accès multiple (IAM). On étude les performances d'un récepteur multiutilisateurs utilisant des antennes multiples en émission et en réception. On considère ici un système haut débit donc utilisant de faibles facteurs d'étalement conjointement avec une modulation de phase à huit états (MDP-8). Ce genre de système est sujet à des niveaux d' interférences élevés et le but de cet article est de montrer que l'utilisation d'antennes multiples combiné avec l'emploi d'un codage spatio-temporel permet d'obtenir d'excellentes performances et un gain de capacité important même en présence de canaux à évanouissements corrélés et d'effets Doppler élevés. Les codes spatio-temporels employés sont de type STBC (Space-Time Block Code). Une méthode originale pour l'estimation des paramètres de canal sera également présentée

Single-cell delineation of lineage and genetic identity in the mouse brain

During neurogenesis, mitotic progenitor cells lining the ventricles ofthe embryonic mouse brain undergo their final rounds of cell division, giving rise to a wide spectrum of postmitotic neurons and glia(1,2). The link between developmental lineage and cell-type diversity remains an open question. Here we used massively parallel tagging of progenitors to track clonal relationships and transcriptomic signatures during mouse forebrain development. We quantified clonal divergence and convergence across all major cell classes postnatally, and found diverse types of GABAergic neuron that share a common lineage. Divergence of GABAergic clones occurred during embryogenesis upon cell-cycle exit, suggesting that differentiation into subtypes is initiated as a lineage-dependent process at the progenitor cell level

Prevalence of Cannabis Lifetime Use in Iranian High School and College Students: A Systematic Review, Meta-Analyses,and Meta-Regression

Cannabis is the most widely used substance in the world. This study aimed to estimate the prevalence of cannabis lifetime use (CLU) in high school and college students of Iran and also to determine factors related to changes in prevalence. A systematic review of literature on cannabis use in Iran was conducted according to MOOSE guideline. Domestic scientific databases, PubMed/Medline, ISI Web of Knowledge, and Google Scholar, relevant reference lists, and relevant journals were searched up to April, 2014. Prevalences were calculated using the variance stabilizing double arcsine transformation and confidence intervals (CIs) estimated using the Wilson method. Heterogeneity was assessed by Cochran's Q statistic and I-2 index and causes of heterogeneity were evaluated using meta-regression model. In electronic database search, 4,000 citations were retrieved, producing a total of 33 studies. CLU was reported with a random effects pooled prevalence of 4.0 (95 CI = 3.0 to 5.0). In subgroups of high school and college students, prevalences were 5.0 (95 CI = 3.0 to -7.0) and 2.0 (95 CI = 2.0 to -3.0), respectively. Meta-regression model indicated that prevalence is higher in college students (beta = 0.089, p < .001), male gender (beta = 0.017, p < .001), and is lower in studies with sampling versus census studies (beta = -0.096, p < .001). This study reported that prevalence of CLU in Iranian students are lower than industrialized countries. In addition, gender, level of education, and methods of sampling are highly associated with changes in the prevalence of CLU across provinces

Combinations of Plant Water-Stress and Neonicotinoids Can Lead to Secondary Outbreaks of Banks Grass Mite (Oligonychus Pratensis Banks)

Spider mites, a cosmopolitan pest of agricultural and landscape plants, thrive under hot and dry conditions, which could become more frequent and extreme due to climate change. Recent work has shown that neonicotinoids, a widely used class of systemic insecticides that have come under scrutiny for non-target effects, can elevate spider mite populations. Both water-stress and neonicotinoids independently alter plant resistance against herbivores. Yet, the interaction between these two factors on spider mites is unclear, particularly for Banks grass mite (Oligonychus pratensis; BGM). We conducted a field study to examine the effects of water-stress (optimal irrigation = 100% estimated evapotranspiration (ET) replacement, water stress = 25% of the water provided to optimally irrigated plants) and neonicotinoid seed treatments (control, clothianidin, thiamethoxam) on resident mite populations in corn (Zea mays, hybrid KSC7112). Our field study was followed by a manipulative field cage study and a parallel greenhouse study, where we tested the effects of water-stress and neonicotinoids on BGM and plant responses. We found that water-stress and clothianidin consistently increased BGM densities, while thiamethoxam-treated plants only had this effect when plants were mature. Water-stress and BGM herbivory had a greater effect on plant defenses than neonicotinoids alone, and the combination of BGM herbivory with the two abiotic factors increased the concentration of total soluble proteins. These results suggest that spider mite outbreaks by combinations of changes in plant defenses and protein concentration are triggered by water-stress and neonicotinoids, but the severity of the infestations varies depending on the insecticide active ingredient

Eranshahr: Uomo, ambiente e società nell’Iran arsacide e sasanide. Testimonianze scritte, cultura materiale e società da Arsace a Yazdegard III

L’arco temporale che si pone a cavallo tra due transizioni politiche di notevole importanza, la prima tra la dinastia dei Seleucidi e quella degli Arsacidi, la seconda tra la dinastia dei Sasanidi e il califfato islamico, costituisce un contesto cruciale per la messa in pratica di diversi approcci metodologici volti alla comprensione delle relazioni tra uomo, potere politico e territorio nell’Iran tra III sec. a.C. e VII d.C. In tale quadro si è scelto di focalizzare l’attenzione su tre aree nodali dell’Iran antico: le regioni storiche dell’Elimaide (Khuzestan), della Persia (Pars) e della Media (Mad e Pahlaw). Le regioni prese in considerazione, pur caratterizzate da notevoli differenze, furono al centro delle trasformazioni del periodo e forniscono informazioni utili per la ricostruzione di specifiche dinamiche storico-culturali