Endogenous Taxation in Ongoing Internal Conflict: The Case of Colombia

Recent empirical evidence suggests an ambiguous relationship between internal conflicts, state capacity, and tax performance. In theory, internal conflict should create strong incentives for governments to develop the fiscal capacity necessary to defeat rivals. We argue that one reason that this does not occur is because internal conflict enables groups with de facto power to capture local fiscal and property rights institutions. We test this mechanism in Colombia using data on tax performance and property rights institutions at the municipal level. Municipalities affected by internal conflict have tax institutions consistent with the preferences of the parties dominating local violence. Those suffering more right-wing violence feature more land formalization and higher property tax revenues. Municipalities with substantial left-wing guerrilla violence collect less tax revenue and witness less land formalization. Our findings provide systematic evidence that internal armed conflict helps interest groups capture municipal institutions for their own private benefit, impeding state-building. Copyright © American Political Science Association 2018

The RNA interference pathway affects midgut infection- and escape barriers for Sindbis virus in Aedes aegypti

<p>Abstract</p> <p>Background</p> <p>The RNA interference (RNAi) pathway acts as an innate antiviral immune response in <it>Aedes aegypti</it>, modulating arbovirus infection of mosquitoes. Sindbis virus (SINV; family: <it>Togaviridae</it>, genus: <it>Alphavirus</it>) is an arbovirus that infects <it>Ae. aegypti </it>in the laboratory. SINV strain TR339 encounters a midgut escape barrier (MEB) during infection of <it>Ae. aegypti</it>. The nature of this barrier is not well understood. To investigate the role of the midgut as the central organ determining vector competence for arboviruses, we generated transgenic mosquitoes in which the RNAi pathway was impaired in midgut tissue of bloodfed females. We used these mosquitoes to reveal effects of RNAi impairment in the midgut on SINV replication, midgut infection and dissemination efficiencies, and mosquito longevity.</p> <p>Results</p> <p>As a novel tool for studying arbovirus-mosquito interactions, we engineered a transgenic mosquito line with an impaired RNAi pathway in the midgut of bloodfed females by silencing expression of the <it>Aa</it>-<it>dcr2 </it>gene. In midgut tissue of the transgenic Carb/dcr16 line, <it>Aa</it>-<it>dcr2 </it>expression was reduced ~50% between 1-7 days post-bloodmeal (pbm) when compared to the recipient mosquito strain. After infection with SINV-TR339EGFP, <it>Aa</it>-<it>dcr2 </it>expression levels were enhanced in both mosquito strains. In the RNAi pathway impaired mosquito strain SINV titers and midgut infection rates were significantly higher at 7 days pbm. There was also a strong tendency for increased virus dissemination rates among the transgenic mosquitoes. Between 7-14 days pbm, SINV was diminished in midgut tissue of the transgenic mosquitoes. Transgenic impairment of the RNAi pathway and/or SINV infection did not affect longevity of the mosquitoes.</p> <p>Conclusions</p> <p>We showed that RNAi impaired transgenic mosquitoes are a useful tool for studying arbovirus-mosquito interactions at the molecular level. Following ingestion by <it>Ae. aegypti</it>, the recombinant SINV-TR339EGFP was confronted with both MEB and a midgut infection barrier (MIB). Impairment of the RNAi pathway in the midgut strongly reduced both midgut barriers for the virus. This confirms that the endogenous RNAi pathway of <it>Ae. aegypti </it>modulates vector competence for SINV in the midgut. The RNAi pathway acts as a gatekeeper to the incoming virus by affecting infection rate of the midgut, intensity of infection, and dissemination from the midgut to secondary tissues.</p

La incorporación de la extensión forestal en la formación del profesional forestal en la Universidad Nacional, Costa Rica

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PATOGENICIDAD Y RESPUESTA SEROLÓGICA DE LAS TÓRTOLAS (Eupelia cruziana) FRENTE A UN DESAFÍO EXPERIMENTAL CON UN VIRUS DE LA ENFERMEDAD DE NEWCASTLE

Con el objetivo de evaluar la susceptibilidad de la Eupelia cruziana (tórtola) al virus de la enfermedad de Newcastle, se inocularon 15 aves adultas con una cepa de virus velogénico viscerotrópico de la enfermedad de Newcastle y 15 fueron usadas como control. Ambos grupos fueron sometidos a similares condiciones ambientales y de alimentación pero en lugares separados. Se llevó un registro de signos clínicos y mortalidad y se tomaron muestras de sangre para la prueba de Inhibición de la Hemaglutinación y muestras de tejidos para evaluación histopatológica y recuperación viral. Seis aves del grupo inoculado presentaron signos clínicos de tipo nervioso (tremores en cabeza, torsión de pescuezo e incoordinación para desplazarse) y tres de éstas murieron. Lesiones macroscópicas y microscópicas fueron observadas en el sistema nervioso y en el análisis histopatológico se observaron lesiones en tráquea y pulmón. Se registró un incremento en los niveles de anticuerpos a partir de los 7 días post-inoculación alcanzando el mayor promedio geométrico de títulos (PGT = 12.1) a los 21 días. Se logró la recuperación viral a partir de pulmón, tráquea e hisopado de cloaca en aves muertas por la enfermedad.This study was designed to assess the susceptibility of turtle-doves (Eupelia cruziana) to Newcastle virus. A group of 15 turtle-doves was inoculated with a velogenic viscerotropic strain of the Newcastle virus, and a group of 15 was used as control. Both groups were raised in the same environmental conditions and were fed with similar feeds, but kept separate. Clinical signs and mortality were recorded. Blood samples were tested by the hemaglutination inhibition technique and tissue samples were collected for virus recovery and histological studies. From the inoculated group, 6 birds showed nervous signs like head tremors, neck torsion and uncoordinated movements, and three of them died. Macroscopic lesions were observed on the nervous system. Histological lesions were observed in the brain, and in lungs and tracheal epithelium. An increase in the antibody titers was observed at the 7th day of exposure to Newcastle virus, reaching the highest titers (PGT= 12.1) at the 21th day. Viral recovery was obtained in lung and trachea tissues, and from a cloacal swab from dead birds

The prevalence of axial spondyloarthritis in the UK: a cross-sectional cohort study

Background: Accurate prevalence data are important when interpreting diagnostic tests and planning for the health needs of a population, yet no such data exist for axial spondyloarthritis (axSpA) in the UK. In this cross-sectional cohort study we aimed to estimate the prevalence of axSpA in a UK primary care population. Methods: A validated self-completed questionnaire was used to screen primary care patients with low back pain for inflammatory back pain (IBP). Patients with a verifiable pre-existing diagnosis of axSpA were included as positive cases. All other patients meeting the Assessment of SpondyloArthritis international Society (ASAS) IBP criteria were invited to undergo further assessment including MRI scanning, allowing classification according to the European Spondyloarthropathy Study Group (ESSG) and ASAS axSpA criteria, and the modified New York (mNY) criteria for ankylosing spondylitis (AS). Results: Of 978 questionnaires sent to potential participants 505 were returned (response rate 51.6 %). Six subjects had a prior diagnosis of axSpA, 4 of whom met mNY criteria. Thirty eight of 75 subjects meeting ASAS IBP criteria attended review (mean age 53.5 years, 37 % male). The number of subjects satisfying classification criteria was 23 for ESSG, 3 for ASAS (2 clinical, 1 radiological) and 1 for mNY criteria. This equates to a prevalence of 5.3 % (95 % CI 4.0, 6.8) using ESSG, 1.3 % (95 % CI 0.8, 2.3) using ASAS, 0.66 % (95 % CI 0.28, 1.3) using mNY criteria in chronic back pain patients, and 1.2 % (95 % CI 0.9, 1.4) using ESSG, 0.3 % (95 % CI 0.13, 0.48) using ASAS, 0.15 % (95 % CI 0.02, 0.27) using mNY criteria in the general adult primary care population. Conclusions: These are the first prevalence estimates for axSpA in the UK, and will be of importance in planning for the future healthcare needs of this population. Trial registration: Current Controlled Trials ISRCTN7687321

Ultra-strong Adhesion of Graphene Membranes

As mechanical structures enter the nanoscale regime, the influence of van der Waals forces increases. Graphene is attractive for nanomechanical systems because its Young's modulus and strength are both intrinsically high, but the mechanical behavior of graphene is also strongly influenced by the van der Waals force. For example, this force clamps graphene samples to substrates, and also holds together the individual graphene sheets in multilayer samples. Here we use a pressurized blister test to directly measure the adhesion energy of graphene sheets with a silicon oxide substrate. We find an adhesion energy of 0.45 \pm 0.02 J/m2 for monolayer graphene and 0.31 \pm 0.03 J/m2 for samples containing 2-5 graphene sheets. These values are larger than the adhesion energies measured in typical micromechanical structures and are comparable to solid/liquid adhesion energies. We attribute this to the extreme flexibility of graphene, which allows it to conform to the topography of even the smoothest substrates, thus making its interaction with the substrate more liquid-like than solid-like.Comment: to appear in Nature Nanotechnolog