In the wake: Interpreting care and global health through Black geographies

Building on Black geographies and Black studies, this paper offers critical theoretical reflections on global health interventions in postcolonial societies. Drawing on the work of Christina Sharpe, Katherine McKittrick, and Frantz Fanon I suggest that an epistemic approach rooted in Black studies can offer a novel approach to the study of global health interventions, one that centres Black life, which has long been the subject of colonial violence in medical emergencies. I argue that, given the past history of colonialism and medicine, such an approach is warranted if we seek to decolonise the study and practice of global health interventions. By offering what I call “geographies of the wake,” I focus on care's spatial and political entanglements with violence. I make mention of the initial refusal by Sierra Leoneans to seek care in Ebola Treatment Centres and Holding Units and illustrate the spatial aftermath of colonialism and slavery by offering a brief history of one site long associated with care. I ask that this be read as an analytical opening to, not a comprehensive explanation of, Black geographies, global health and medical care

New modelling technique for aperiodic-sampling linear systems

A general input-output modelling technique for aperiodic-sampling linear systems has been developed. The procedure describes the dynamics of the system and includes the sequence of sampling periods among the variables to be handled. Some restrictive conditions on the sampling sequence are imposed in order to guarantee the validity of the model. The particularization to the periodic case represents an alternative to the classic methods of discretization of continuous systems without using the Z-transform. This kind of representation can be used largely for identification and control purposes.Comment: 19 pages, 0 figure

A Quest for Justice in Cuzco, Peru:Race and Evidence in the Case of Mercedes Ccorimanya Lavilla

The life of Mercedes Ccorimanya Lavilla renders a telling portrait of the pursuit of justice in Cuzco, Peru, revealing how courts of law can be key sites in the production and negotiation of racial and gender taxonomies. Mercedes (who was gang-raped as a young woman) illustrates the near-heroic efforts necessary to mount and pursue rape charges in Peruvian courts, where rape victims largely manage the construction of evidence in lieu of the state. In the following article, I reconstruct the social circumstances and legal institutional setting surrounding the rape trial of Mercedes Ccorimanya Lavilla through the use of historical and ethnographic materials. In arguing that race mutually defines women's sexuality in rural Peru, I show how (in order to achieve a conviction) Mercedes had to develop a strategy in which she instrumentally employed the languages of race to distance herself from her own indigeneity, as well as that of her alleged attackers

Dislocation Emission around Nanoindentations on a (001) fcc Metal Surface Studied by STM and Atomistic Simulations

We present a combined study by Scanning Tunneling Microscopy and atomistic simulations of the emission of dissociated dislocation loops by nanoindentation on a (001) fcc surface. The latter consist of two stacking-fault ribbons bounded by Shockley partials and a stair-rod dislocation. These dissociated loops, which intersect the surface, are shown to originate from loops of interstitial character emitted along the directions and are usually located at hundreds of angstroms away from the indentation point. Simulations reproduce the nucleation and glide of these dislocation loops.Comment: 10 pages, 4 figure

Minimal entropy and geometric decompositions in dimension four

We show vanishing results about the infimum of the topological entropy of the geodesic flow of homogeneous smooth four manifolds. We prove that any closed oriented geometric four manifold has zero minimal entropy if and only if it has zero simplicial volume. We also show that if a four manifold M admits a geometric decomposition, in the sense of Thurston, and does not have geometric pieces modelled on hyperbolic four-space, the complex hyperbolic plane or the product of two hyperbolic planes, then M admits an F-structure. It follows that M has zero minimal entropy and collapses with curvature bounded from below. We then analyse whether or not M admits a metric whose topological entropy coincides with the minimal entropy of M and provide new examples of manifolds for which the minimal entropy problem cannot be solved.Comment: 38 pages, corrected flat case; Theorem A is now in terms of F-structures, improved exposition; new final section collects all results needed for the proofs of the main theorem

Predicting species abundance by implementing the ecological niche theory

Species are not uniformly distributed across the landscape. For every species, there should be few favoured sites where abundance is high and many other sites of lower suitability where abundance is low. Consequently, local abundance could be thought of as a natural expression of species response to local conditions. The correlation between abundance and environmental suitability has been well documented, and a recent meta-analysis has suggested that this relationship could be a generality. Despite the importance and potential implication of the abundance–suitability relationship, its predictive power for meaningful extrapolations has been surprisingly poorly explored. In this study, we showed how a highly predictable trend can be extracted from the abundance–suitability relationship, accurately predicting the variation in species abundance at a high spatial resolution. We produced high-quality environmental suitability estimations for 50 endemic species in the Australian Wet Tropics. Environmental suitability derived from species distribution models was related to observed abundance estimated using data from 29 years of uninterrupted monitoring effort. We used the fitted relationship to accurately predict abundance at a fine scale across the species range. Our results showed that the abundance–suitability relationship was strong for endemic species in the Australian Wet Tropics. The predictive power of our models was high, explaining, on average, 55% of the deviance across taxa. Despite interspecific variation in the strength of the abundance–suitability relationship associated with potential intrinsic estimation biases, our approach provides a powerful tool for predicting abundance across the species range at a fine scale. The potential for robust abundance predictions from occurrence-based species distribution models shown in this study are numerous, and it could have a significant impact in enhancing species conservation and management decisions

Predicted alteration of vertebrate communities in response to climate-induced elevational shifts

Aim: Climate change is driving species to migrate to novel areas as current environments become unsuitable. As a result, species distributions have shifted uphill in montane ecosystems globally. Heterogeneous dispersal rates among shifting species could result in complex changes to community assemblages. For example, interspecific differences in dispersal ability could lead to the disruption, or creation, of species interactions and processes within communities, likely amplifying the impact of climate change on ecosystems. Here, we studied the dispersal success of vertebrate species in a tropical montane ecosystem under a climate-induced uphill shift and assessed the derived impacts on community structures. Location: The Australian Wet Tropics bioregion. Method: We simulated the uphill shift of 7613 community assemblages across the elevational gradient using thermal resistance layers for movement analyses. Dispersal success was calculated as the probability of shifting given species’ dispersal ability and landscape composition. We then used dissimilarity indices to measure the potential changes in community structures resulting from the heterogeneous dispersal success among migrating species. Results: Dispersal success was strongly influenced by species’ dispersal ability, landscape composition and climate change. The heterogeneous dispersal success among migrating species induced marked temporal changes between community assemblages along the elevational gradient. The local extinction rate (i.e. the proportion of species unable to shift) was especially remarkable at high elevations, suggesting potential mass local extinctions of upland species. Furthermore, the increasing local extinction rate with elevation resulted in substantial declines in species co-occurrence in high-altitude ecosystems. Main conclusions: Our study highlights the escalating impact of climate change on community assemblages in response to climate-induced elevational shifts, providing a classic example of the "escalator to extinction." Future predictions of the impacts of climate change on ecosystems will benefit from improvements in understanding species interactions, population dynamics and species potential to adapt to a changing environment

Long-term persistence and adherence on urate-lowering treatment can be maintained in primary care-5-year follow-up of a proof-of-concept study

Objectives: To evaluate the persistence and adherence on urate-lowering treatment (ULT) in primary care 5 years after an initial nurse-led treatment of gout. Methods: One hundred gout patients initiated on up-titrated ULT between March and July 2010 were sent a questionnaire that elicited information on current ULT, reasons for discontinuation of ULT if applicable, medication adherence and generic and disease-specific quality-of-life measures in 2015. They were invited for one visit at which height and weight were measured and blood was collected for serum uric acid measurement. Results: Seventy-five patients, mean age 68.13 years ( s . d . 10.07) and disease duration 19.44 years ( s . d . 13), returned completed questionnaires. The 5-year persistence on ULT was 90.7% (95% CI 81.4, 91.6) and 85.3% of responders self-reported taking ULT ⩾6 days/week. Of the 65 patients who attended the study visit, the mean serum uric acid was 292.8 μmol/l ( s . d . 97.2). Conclusion: An initial treatment that includes individualized patient education and involvement in treatment decisions results in excellent adherence and persistence on ULT >4 years after the responsibility of treatment is taken over by the patient's general practitioner, suggesting that this model of gout management should be widely adopted

Canonical Melnikov theory for diffeomorphisms

We study perturbations of diffeomorphisms that have a saddle connection between a pair of normally hyperbolic invariant manifolds. We develop a first-order deformation calculus for invariant manifolds and show that a generalized Melnikov function or Melnikov displacement can be written in a canonical way. This function is defined to be a section of the normal bundle of the saddle connection. We show how our definition reproduces the classical methods of Poincar\'{e} and Melnikov and specializes to methods previously used for exact symplectic and volume-preserving maps. We use the method to detect the transverse intersection of stable and unstable manifolds and relate this intersection to the set of zeros of the Melnikov displacement.Comment: laTeX, 31 pages, 3 figure