36 research outputs found

    Nicoya Peninsula, Costa Rica: A single suite of Caribbean oceanic plateau magmas

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    The pre‐Tertiary oceanic crust exposed on the west coast of Costa Rica has been broadly referred to as the Nicoya Complex. This study was designed to determine the age of the Nicoya Complex in the Nicoya Peninsula, Playa Jacó, and the Quepos Peninsula using 40Ar‐39Ar radiometric dating and to assess the petrologic relationships between the different localities using major element, trace element, and Sr, Nd, Pb isotopic data. Radiometric ages of basalts and diabases from the Nicoya Peninsula are 88–90 Ma (with a weighted mean of 88.5 Ma), and those of two intrusive rocks (a gabbro and plagiogranite) are both 83–84 Ma. The combined geochemical data indicate that the sampled Nicoya Peninsula rocks belong to a single suite related by fractional crystallization of similar parental magmas. Nd and Pb isotopic ratios indicate a common mantle source distinct from that of mid‐ocean ridge basalts. Both the age and composition of the Nicoya rocks are consistent with the idea that they are a part of the Caribbean Cretaceous oceanic plateau [Donnelly, 1994]. The Jacó lavas are geochemically similar to the Nicoya Peninsula suite, and a single age of 84 Ma is identical to the age of the Nicoya Peninsula intrusives. The one analyzed Quepos basalt has a radiometric age of ∼64 Ma, and it is enriched in incompatible elements relative to the Nicoya rocks. Similarities in Nd and Pb isotopic ratios indicate that the Quepos and Nicoya/Jacó lavas were derived from a similar mantle source to that which produced the Nicoya rocks, possibly the Galapagos plume

    Enterococcus faecalis demonstrates pathogenicity through increased attachment in an ex vivo polymicrobial pulpal infection

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    This study investigated the host response to a polymicrobial pulpal infection consisting of Streptococcus anginosus and Enterococcus faecalis, bacteria commonly implicated in dental abscesses and endodontic failure, using a validated ex vivo rat tooth model. Tooth slices were inoculated with planktonic cultures of S. anginosus or E. faecalis alone or in co-culture at ratios of 50:50 and 90:10 S. anginosus to E. faecalis. Attachment was semi-quantified by measuring area covered by fluorescently labelled bacteria. Host response was established by viable histological cell counts and inflammatory response using RT-qPCR and immunohistochemistry. A significant reduction in cell viability was observed for single and polymicrobial infections, with no significant differences between infection types (≈2000cells/mm2 for infected pulps compared to ≈4000cells/mm2 for uninfected pulps). E. faecalis demonstrated significantly higher levels of attachment (6.5%) compared to S. anginosus alone (2.3%) and mixed species infections (3.4% for 50:50 and 2.3% for 90:10), with a remarkable affinity to the pulpal vasculature. Infections with E. faecalis demonstrated the greatest increase in TNF-α (47.1 fold for E. faecalis, 14.6 fold for S. anginosus, 60.1 fold for 50:50 and 25.0 fold for 90:10) and IL-1β expression (54.8 fold for E. faecalis, 8.8 fold for S. anginosus, 54.5 fold for 50:50 and 39.9 fold for 90:10) when compared to uninfected samples. Immunohistochemistry confirmed this with the majority of inflammation localised to the pulpal vasculature and odontoblast regions. Interestingly, E. faecalis supernatant and heat killed E. faecalis treatment was unable to induce the same inflammatory response, suggesting E. faecalis pathogenicity in pulpitis is linked to its greater ability to attach to the pulpal vasculature

    Colonial lives of the carceral archipelago: rethinking the neoliberal security state

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    Mass incarceration, police brutality, and border controls are part and parcel of the everyday experiences of marginalized and racialized communities across the world. Recent scholarship in international relations, sociology, and geography has examined the prevalence of these coercive practices through the prism of “disciplinary,” “penal,” or “authoritarian” neoliberalism. In this collective discussion, we argue that although this literature has brought to the fore neoliberalism's reliance on state violence, it has yet to interrogate how these carceral measures are linked to previous forms of global racial ordering. To rectify this moment of “colonial unknowing,” the collective discussion draws on decolonial approaches, Indigenous studies, and theories of racial capitalism. It demonstrates that “new” and “neoliberal” forms of domestic control must be situated within the global longue durée of racialized and colonial accumulation by dispossession. By mapping contemporary modes of policing, incarceration, migration control, and surveillance onto earlier forms of racial–colonial subjugation, we argue that countering the violence of neoliberalism requires more than nostalgic appeals for a return to Keynesianism. What is needed is abolition—not just of the carceral archipelago, but of the very system of racial capitalism that produces and depends on these global vectors of organized violence and abandonment. L'incarcération de masse, la brutalité policière et les contrôles aux frontières constituent une partie intégrante des expériences quotidiennes des communautés marginalisées et racialisées du monde entier. Des études récentes en relations internationales, en sociologie et en géographie ont examiné la prévalence de ces pratiques coercitives par le prisme du néolibéralisme « disciplinaire », « pénal » ou « autoritaire ». Dans cet article, nous soutenons que bien que cette littérature ait mis en évidence la dépendance du néolibéralisme à la violence étatique, elle ne s'est pas encore interrogée sur le lien entre ces mesures carcérales et les formes précédentes d'ordre racial mondial. Cet article s'appuie sur le féminisme noir, les approches décoloniales, les études indigènes et les théories de capitalisme racial pour rectifier cette « ignorance coloniale » marquante. Il démontre que les formes « nouvelles » et « néolibérales » de contrôle national doivent se situer dans la longue durée globale de l'accumulation racialisée et coloniale par dépossession. Nous associons les modes contemporains de maintien de l'ordre, d'incarcération, de contrôle migratoire et de surveillance à des formes antérieures d'assujettissement racial/colonial pour soutenir que contrer la violence du néolibéralisme exige davantage que des appels nostalgiques au retour du keynésianisme. Ce qu'il faut, c'est une abolition : non seulement de l'archipel carcéral, mais aussi du système de capitalisme racial en lui-même qui produit et dépend de ces vecteurs globaux de violence organisée et d'abandon. El encarcelamiento masivo, la brutalidad policial y los controles fronterizos forman parte de las experiencias cotidianas de las comunidades marginadas y racializadas de todo el mundo. Estudios recientes en RI, Sociología y Geografía han examinado la prevalencia de estas prácticas coercitivas a través del prisma del neoliberalismo “disciplinario,” “penal” o “autoritario.” En este artículo, sostenemos que, si bien esta literatura puso en primer plano la dependencia del neoliberalismo de la violencia estatal, aún tiene que cuestionar la manera en que estas medidas carcelarias se vinculan a formas anteriores de ordenamiento racial global. Para rectificar este momento de “desconocimiento colonial,” el artículo recurre al feminismo negro, a los abordajes descoloniales, a los estudios indígenas y a las teorías del capitalismo racial. Demuestra que las formas “nuevas” y “neoliberales” de control interno se deben situar dentro de la longue durée global de la acumulación por desposesión racializada y colonial. Al trazar un mapa de los modos contemporáneos de vigilancia policial, encarcelamiento, control de la migración y vigilancia sobre las formas anteriores de subyugación racial-colonial, sostenemos que contrarrestar la violencia del neoliberalismo requiere algo más que apelaciones nostálgicas de retorno al keynesianismo. Lo que se necesita es la abolición, no solo del archipiélago carcelario, sino también del propio sistema de capitalismo racial que produce y depende de estos vectores globales de violencia y abandono organizados

    Managing distance in international purchasing and supply: a systematic review of literature from the resource-based view perspective

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    The aim of this research is to find out how the extant literature on international purchasing and supply management (PSM) covers the elements of capability from the perspective of distance. A priori, we form a framework of capability driving elements and conclude that distance—in its multiple dimensions—is the fundamental management aspect in international PSM. Equipped with analytical frameworks and a bottom–up process for identifying emergent themes, a systematic literature review was conducted on a representative sample of scholarly literature on international PSM, using the NVivo analysis software and a data display as tools. We identify several capability relevant themes from the literature, and provide a distance-based a posteriori conceptualisation of international PSM, founded in the information processing theory, with the source-user, user-user and source-source distance types driving the information processing requirements, and loading avoidance, policy-based and enhancement mechanisms determining the information processing capacity

    Action of Disinfectant Quaternary Ammonium Compounds against Staphylococcus aureus

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    Mode-of-action studies concluded that alkyldimethylbenzylammonium chloride (ADBAC) (a blend of C(12), C(14) and C(16) alkyl homologues) and didecyldimethylammonium chloride (DDAC) are both membrane-active agents, possessing subtly different modes of action reflecting early cell interactions against Staphylococcus aureus. ADBAC and DDAC exhibited similar MIC behaviors from 0.4 ppm to 1.8 ppm over an inoculum range of 1 × 10(5) to 1 × 10(9) CFU/ml at 35°C. For ADBAC and DDAC, an increased rapidity of killing against S. aureus (final concentration, 2 × 10(9) CFU/ml) was observed at 35°C compared to 25°C. Concentration exponents (η) for killing were <2.5 for both agents, and temperature influenced the η value. Examination of leakage and kill data suggested that a single leakage marker was not indicative of cell death. ADBAC and DDAC possessed Langmuir (L4) and high-affinity (H3/4) uptake isotherms, respectively. ADBAC molecules formed a single monolayer of coverage of cells at the end of primary uptake, and DDAC formed a double monolayer. Rapid cell leakage occurred at bactericidal concentrations, with total depletion of the intracellular potassium and 260-nm-absorbing pools released in this strict order. Autolysis was observed for ADBAC and DDAC at concentrations of 9 μg/ml (0.0278 mM and 0.0276 mM, respectively) and above, together with the depletion of approximately 30% of the internal potassium pool. Autolysis contributed to ADBAC and DDAC lethality, although high biocide concentrations may have inhibited autolytic enzyme activity

    Chest Impedance Imaging Using Trigonometric Current Patterns

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    This paper reports the results from the application of the 32 channel Oxford Brookes Adaptve Current Tomograph, OXBACT-III to the chest of a human volunteer. A frame rate of 10 per second was achieved using trigonometric drive currents
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