Quantitative mapping of scleral fiber orientation in normal rat eyes

Purpose. Previous work has suggested a major role of scleral biomechanics in the pathogenesis of glaucoma. Since fiber orientation in connective tissues is a key determinant of tissue biomechanics, experimental characterization of scleral fiber orientation is needed to fully understand scleral biomechanics. This is a report of baseline experimental measurements of fiber orientation in whole normal rat scleras. Methods. Twenty ostensibly normal Norway brown rat eyes were fixed in 4% paraformaldehyde. The scleras were cleaned of intra- and extraorbital tissues and dissected into five patches, and each patch was glycerol treated to maximize its transparency. Fiber orientation was measured using small-angle light scattering (SALS). Scattering patterns were analyzed to extract two microstructural parameters at each measurement location—the preferred fiber orientation and the degree of alignment—yielding a fiber orientation map for each sclera. Results. Rat sclera is structurally anisotropic with several consistent features. At the limbus, fibers were highly aligned and organized primarily into a distinct ring surrounding the cornea. In the equatorial region, the fibers were primarily meridionally aligned. In the posterior and peripapillary region, the scleral fibers were mostly circumferential but less aligned than those in the anterior and equatorial regions. Conclusions. Circumferential scleral fibers may act as reinforcing rings to limit corneal and optic nerve head deformations, whereas equatorial meridional fibers may either provide resistance against extraocular muscle forces or limit globe axial elongation

Indigenous identity, natural resources, and contentious politics in Bolivia: a disaggregated conflict analysis; 2000-2011

How do natural resources and ethnic identity interact to incite or to mitigate social conflict? This article argues that high-value natural resources can act as an important catalyst for the politicization of ethnic, specifically indigenous identity, and contribute to social conflict as they limit the malleability of identity frames and raise the stakes of confrontations. We test this argument using unique subnational data from Bolivian provinces. Drawing on Bolivian newspaper reports, we code conflict events for all of the 112 provinces from 2000 to 2011. We join this conflict data with information on local ethnic composition from the census, the political representation of ethnic groups at the national level, as well as geo-spatial information on gas deposits. Using time-series cross-sectional count models, we show a significant conflict-promoting effect of the share of indigenous people in provinces with gas reserves, but not without

A DNA-based real-time PCR assay for robust growth quantification of the bacterial pathogen Pseudomonas syringae on Arabidopsis thaliana

Abstract Background The interaction of Pseudomonas syringae with Arabidopsis is one of the most commonly used systems to study various bacterial—host interrelationships. Currently, most studies are based on the growth quantification of the pathogen to characterize resistance or virulence targets. However, the standard available method for determining bacterial proliferation in planta is laborious and has several limitations. Results Here we present an alternative robust approach, which is based on the quantification of bacterial DNA by real-time PCR. We directly compared this assay with the routinely used plate counting method to access bacterial titers in a number of well described Arabidopsis mutants. Conclusions These studies showed that the DNA-based technique is highly reliable and comparable. Moreover, the technique is easily applicable, robust, and ideal for routine experiments or for larger scale analyses

MOESM1 of A DNA-based real-time PCR assay for robust growth quantification of the bacterial pathogen Pseudomonas syringae on Arabidopsis thaliana

Additional file 1: Figure S1. Amplification of the oprF gene product by qRT-PCR using different DNA inputs from several organisms

Revisiting the Resource-Conflict Link: A Systematic Comparative Test of Causal Mechanisms in Four Major Oil-Exporting Countries

Causal mechanisms and related contextual variables are crucial to the study of the resource-conflict link, but little systematic research has been done on their exact functioning. This paper contributes to the filling of this gap by comparing four major oil exporters (Algeria, Iran, Nigeria, and Venezuela) with differing levels of internal violence. To capture the causal complexity of the resource-conflict link we created a questionnaire with some 150 variables that distinguish between resource-specific (RS) and non-resource specific (NRS) conditions. The causal mechanisms are measured by assigning pertinent RS and NRS indicators to them. Our results suggest that the role of resources may be less prominent than is widely assumed. Only three resource-related causal mechanisms provide limited explanatory value (motive at subnational level, indirect economic, and institutional mechanism) by distinguishing Venezuela-the most peaceful case-from all the others. Only a mixed mechanism that combines 13 RS and NRS (economic and geographic characteristics, identity, intergroup relations, as well as political and institutional variables, including elite behavior) conditions can explain the differences between the countries with regard to the dependent variable comprehensively

Conflict Prevention Through Natural Resource Management? A Comparative Study

Natural resources are often held responsible for intrastate conflicts. As a consequence, both national and international measures to avoid the detrimental impact of resource endowments have increasingly been discussed and implemented in resource-rich countries. These measures include stabilization funds, subregional development programs, revenue-sharing regimes, and transparency initiatives. However, comparative empirical studies of the actual impact of these measures, particularly regarding their contribution to conflict prevention, are scarce. This paper contributes to the filling of this gap: combining a medium-N sample of oildependent countries and three in-depth case studies (Algeria, Nigeria, and Venezuela), we evaluate different instruments of resource management and their effects on conflict risk factors. On the one hand, the findings do not show any systematic connection between the countermeasures and a reduction in resource-related risks; on the other, the paper highlights common causal factors for the lack of implementation of resource-related countermeasures.Natürliche Ressourcen gelten als häufige Ursache für innerstaatliche Konflikte. Seit einigen Jahren werden daher Gegenmaßnahmen zur Vermeidung des 'Ressourcenfluchs' verstärkt diskutiert und teilweise bereits umgesetzt. Zu diesen Maßnahmen zählen Stabilisierungsfonds, regionale Entwicklungsprogramme, feste Verteilungsmechanismen für Ressourcenerlöse sowie nationale und internationale Antikorruptions- und Transparenzinitiativen. Bislang liegen jedoch wenige vergleichende Untersuchungen zur Wirkung dieser Maßnahmen hinsichtlich einer Konfliktvermeidung oder -verringerung vor. Mit diesem Arbeitspapier soll dazu beigetragen werden, diese Lücke zu schließen. Anhand von 31 Erdölexporteuren und von drei Fallstudien (Algerien, Nigeria und Venezuela) wird untersucht, welche Gegenmaßnahmen in rohstoffabhängigen Ländern bisher umgesetzt wurden und inwieweit dies einen Einfluss auf ressourcenbezogene Konfliktrisiken hatte. Zwar ist mittels empirischer Analyse kein systematisch positiver Zusammenhang zwischen Gegenmaßnahmen und einer Verminderung dieser Konfliktrisiken festzustellen, jedoch werden gemeinsame Erklärungsfaktoren für eine mangelhafte Implementierung der Gegenmaßnahmen herausgearbeitet