Parallel developmental genetic features underlie stickleback gill raker evolution.

BackgroundConvergent evolution, the repeated evolution of similar phenotypes in independent lineages, provides natural replicates to study mechanisms of evolution. Cases of convergent evolution might have the same underlying developmental and genetic bases, implying that some evolutionary trajectories might be predictable. In a classic example of convergent evolution, most freshwater populations of threespine stickleback fish have independently evolved a reduction of gill raker number to adapt to novel diets. Gill rakers are a segmentally reiterated set of dermal bones important for fish feeding. A previous large quantitative trait locus (QTL) mapping study using a marine × freshwater F2 cross identified QTL on chromosomes 4 and 20 with large effects on evolved gill raker reduction.ResultsBy examining skeletal morphology in adult and developing sticklebacks, we find heritable marine/freshwater differences in gill raker number and spacing that are specified early in development. Using the expression of the Ectodysplasin receptor (Edar) gene as a marker of raker primordia, we find that the differences are present before the budding of gill rakers occurs, suggesting an early change to a lateral inhibition process controlling raker primordia spacing. Through linkage mapping in F2 fish from crosses with three independently derived freshwater populations, we find in all three crosses QTL overlapping both previously identified QTL on chromosomes 4 and 20 that control raker number. These two QTL affect the early spacing of gill raker buds.ConclusionsCollectively, these data demonstrate that parallel developmental genetic features underlie the convergent evolution of gill raker reduction in freshwater sticklebacks, suggesting that even highly polygenic adaptive traits can have a predictable developmental genetic basis

El maestro como formador y cultor de la vida

El presente artículo describe y reflexiona sobre el proceso histórico del quehacer pedagógico y los aspectos fundamentales del maestro como formador y cultor de vida, desde la antigüedad hasta los albores del siglo XXI. El maestro auténtico posee unas características esenciales que lo distinguen como líder, formador y forjador de personas, potenciador de saberes y valores que coadyuvan al desarrollo humano. No sólo enseña contenidos e instruye sino que educa con las actitudes y ejemplos de vida. Se presentan aquí las cualidades del maestro integral en que se conjugan el conocimiento científico, las virtudes intelectuales, el sentido humanista, la visión prospectiva, creadora y transformadora, la defensa de la verdad y de la vida, el cultivo de los valores éticos, la edificación innovadora de la cultura y el compromiso permanente de educar para la libertad

Varied effects of algal symbionts on transcription factor NF-κB in a sea anemone and a coral: possible roles in symbiosis and thermotolerance

Many cnidarians, including the reef-building corals, undergo symbiotic mutualisms with photosynthetic dinoflagellate algae of the family Symbiodiniaceae. These partnerships are sensitive to temperature extremes, which cause symbiont loss and increased coral mortality. Previous studies have implicated host immunity and specifically immunity transcription factor NF-κB as having a role in the maintenance of the cnidarian-algal symbiosis. Here we have further investigated a possible role for NF-κB in establishment and loss of symbiosis in various strains of the anemone Exaiptasia (Aiptasia) and in the coral Pocillopora damicornis. Our results show that NF-κB expression is reduced in Aiptasia larvae and adults that host certain algae strains. Treatment of Aiptasia larvae with a known symbiosis-promoting cytokine, transforming growth factor β, also led to decreased NF-κB expression. We also show that aposymbiotic Aiptasia (with high NF-κB expression) have increased survival following infection with the pathogenic bacterium Serratia marcescens as compared to symbiotic Aiptasia (low NF-κB expression). Furthermore, a P. damicornis coral colony hosting Durusdinium spp. (formerly clade D) symbionts had higher basal NF-κB expression and decreased heat-induced bleaching as compared to two individuals hosting Cladocopium spp. (formerly clade C) symbionts. Lastly, genome-wide gene expression profiling and genomic promoter analysis identified putative NF-κB target genes that may be involved in thermal bleaching, symbiont maintenance, and/or immune protection in P. damicornis. Our results provide further support for the hypothesis that modulation of NF-κB and immunity plays a role in some, but perhaps not all, cnidarian-Symbiodiniaceae partnerships as well as in resistance to pathogens and bleaching.Accepted manuscrip

Metabolomic Shifts Associated with Heat Stress in Coral Holobionts

Understanding the response of the coral holobiont to environmental change is crucial to inform conservation efforts. The most pressing problem is “coral bleaching,” usually precipitated by prolonged thermal stress. We used untargeted, polar metabolite profiling to investigate the physiological response of the coral species Montipora capitata and Pocillopora acuta to heat stress. Our goal was to identify diagnostic markers present early in the bleaching response. From the untargeted UHPLC-MS data, a variety of co-regulated dipeptides were found that have the highest differential accumulation in both species. The structures of four dipeptides were determined and showed differential accumulation in symbiotic and aposymbiotic (alga-free) populations of the sea anemone Aiptasia (Exaiptasia pallida), suggesting the deep evolutionary origins of these dipeptides and their involvement in symbiosis. These and other metabolites may be used as diagnostic markers for thermal stress in wild coral

Plan de mercadeo prospectivo para posicionamiento del fondo de empleados grupo empresarial Colpatria - Coltitulos visión 2011

Mapa, Organigrama, Matriz Dofa, GráficosEste plan prospectivo desarrolla estratégias que logren que el fondo de empleados del grupo empresarial Colpatria Coltitulos responda ante los cambios que el sector solidario viene presentando y asegurando que llegué a un futuro productivo y sostenible.No Abstrac

Duration of shedding of respiratory syncytial virus in a community study of Kenyan children

Background: Our understanding of the transmission dynamics of respiratory syncytial virus (RSV) infection will be better informed with improved data on the patterns of shedding in cases not limited only to hospital admissions. Methods: In a household study, children testing RSV positive by direct immunofluorescent antibody test (DFA) were enrolled. Nasal washings were scheduled right away, then every three days until day 14, every 7 days until day 28 and every 2 weeks until a maximum of 16 weeks, or until the first DFA negative RSV specimen. The relationship between host factors, illness severity and viral shedding was investigated using Cox regression methods. Results: From 151 families a total of 193 children were enrolled with a median age of 21 months (range 1-164 months), 10% infants and 46% male. The rate of recovery from infection was 0.22/person/day (95% CI 0.19-0.25) equivalent to a mean duration of shedding of 4.5 days (95%CI 4.0-5.3), with a median duration of shedding of 4 days (IQR 2-6, range 1-14). Children with a history of RSV infection had a 40% increased rate of recovery i.e. shorter duration of viral shedding (hazard ratio 1.4, 95% CI 1.01-1.86). The rate of cessation of shedding did not differ significantly between males and females, by severity of infection or by age. Conclusion: We provide evidence of a relationship between the duration of shedding and history of infection, which may have a bearing on the relative role of primary versus re-infections in RSV transmission in the community

ENDURALIFE - powered cardiac resynchronisation therapy defibrillator devices for treating heart failure: A NICE Medical Technology Guidance

ENDURALIFE™-powered cardiac resynchronisation therapy defibrillator (CRT-D) devices were the subject of an evaluation by the National Institute for Health and Care Excellence, through its Medical Technologies Evaluation Programme, for the treatment of heart failure. Boston Scientific (manufacturer) submitted a case for the adoption of the technology, claiming that it has a longer battery life resulting in a longer time to CRT-D replacement. Other claimed benefits were fewer complications associated with replacement procedures, fewer hospital admissions, less time spent in hospital and reduced demand on cardiology device implantation rooms. The submission was critiqued by Cedar, an external assessment centre. The submitted clinical evidence showed that ENDURALIFE-powered devices implanted during the period 2008–2010 were superior, in terms of longevity, to other devices at that time. Submitted economic evidence indicated that, because of a reduction in the need for replacement procedures, ENDURALIFE-powered devices were cost saving when compared to comparator devices. Cedar highlighted uncertainty of the applicability of the clinical evidence to devices marketed today. The Medical Technologies Advisory Committee noted that this was unavoidable due to the follow-up time required to study battery life. Clinical experts noted that increased battery life is an important patient benefit. However, centres use devices from multiple manufacturers to negate pressure on clinical services in the event of a major device recall. The clinical and economic evidence showed benefits to the patient, and further analysis requested by the committee suggested that ENDURALIFE-powered CRT-Ds may save between £2120 and £5627 per patient over 15 years through a reduction in the need for replacement procedures. ENDURALIFE-powered CRT-D devices received a positive recommendation in Medical Technologies Guidance 3

prior shared experience and survival of spin-offs from restructured state enterprises

Many organizations, especially in emerging economies, trace their origins to restructured state enterprises, and this study explores the implications of such origins for organizational adaptation to changing environmental conditions. We compare the activity choices and survival chances of spin-offs from restructured state enterprises with those of de novo organizations. We argue that prior shared experience of spin-offs’ managers and employees facilitates the redeployment of routines developed in parent state enterprises. This should predispose spin-offs to pursue familiar activities, but this choice is not completely predetermined, and its survival implications depend on the environmental conditions. Our empirical findings suggest that spin-offs from restructured state enterprises are less likely to engage in new activities than de novo organizations. However, those restructuring spin-offs that do engage in new activities before the regulatory regime shift significantly improve their survival chances after the shift. Moreover, we find that the detrimental effect of the regulatory regime shift and the beneficial effect of engaging in new activities are stronger for spin-offs from restructured state enterprises than for de novo organizations.authorsversionpublishe