Anomalous subdiffusion with multispecies linear reaction dynamics

We have introduced a set of coupled fractional reaction-diffusion equations to model a multispecies system undergoing anomalous subdiffusion with linear reaction dynamics. The model equations are derived from a mesoscopic continuous time random walk formulation of anomalously diffusing species with linear mean field reaction kinetics. The effect of reactions is manifest in reaction modified spatiotemporal diffusion operators as well as in additive mean field reaction terms. One consequence of the nonseparability of reaction and subdiffusion terms is that the governing evolution equation for the concentration of one particular species may include both reactive and diffusive contributions from other species. The general solution is derived for the multispecies system and some particular special cases involving both irreversible and reversible reaction dynamics are analyzed in detail. We have carried out Monte Carlo simulations corresponding to these special cases and we find excellent agreement with theory

Mesoscopic description of reactions under anomalous diffusion: A case study

Reaction-diffusion equations deliver a versatile tool for the description of reactions in inhomogeneous systems under the assumption that the characteristic reaction scales and the scales of the inhomogeneities in the reactant concentrations separate. In the present work we discuss the possibilities of a generalization of reaction-diffusion equations to the case of anomalous diffusion described by continuous-time random walks with decoupled step length and waiting time probability densities, the first being Gaussian or Levy, the second one being an exponential or a power-law lacking the first moment. We consider a special case of an irreversible or reversible A ->B conversion and show that only in the Markovian case of an exponential waiting time distribution the diffusion- and the reaction-term can be decoupled. In all other cases, the properties of the reaction affect the transport operator, so that the form of the corresponding reaction-anomalous diffusion equations does not closely follow the form of the usual reaction-diffusion equations

A learning journey into contemporary bioregionalism

1. Bioregioning is a new wave of bioregional discourse that appears to be attracting interest among sustainability researchers and practitioners. 2. Through interviews with contemporary leaders and a reflexive research process, we explored bioregioning experiences across seven countries. Our paper outlines the motivations, practices and narratives that we encountered and positions these observations against prior expressions of bioregional thought and broader themes in sustainability research. 3. We found that in bioregioning, the concept of a bioregion remains important and seems to attract people to the discourse in three ways: It inspires visions of the future that encompass more-than-human thriving, it creates a conceptual container that enables a strategic narrative for change that connects places to larger scales, and it justifies the importance of everyday people exercising their right to ‘do’ something. 4. The combination of these motivators shows bioregioning's relationship with earlier expressions of bioregional thought: Like early bioregional thinkers, regional scales carry cognitive and strategic appeal, and like critical bioregionalism, power and justice are foregrounded to ensure the process of change is ethical. We suggest that in the shift to bioregioning, the bioregion serves as a boundary device, justifying (for some) a focus on regional scale action which has made bioregional discourse unique, and for others, rationalising participatory or emotional priorities. This lets bioregioning enact a dialogic approach to change and enables practitioners to consider questions of scale in open dialogue with emotive place-based dynamics, bringing nature re-connection and social–ecological systems research into consideration and overlap with the practice of bioregioning. 5. We observed parallels between our research process and the central features in bioregioning; both respond to ambitions and calls within sustainability to enact relational values and surface contextualised knowledge while also valuing generalisations and abstraction. Our study, we suggest, provides one example of how research into human–nature relationships in Western sustainability might be pursued in line with these ambitions

Tenofovir alafenamide: An initial experience at Groote Schuur Hospital, Cape Town, South Africa

Background. Hepatitis B virus (HBV) remains endemic in South Africa (SA), with a concomitantly high prevalence of HIV co-infection. Chronic kidney disease in these subpopulations also has a high prevalence. Tenofovir is an important component of management, but the associated risk of nephrotoxicity makes dosing a challenge in patients with impaired kidney function. A new formulation, tenofovir alafenamide fumarate (TAF), with a more favourable renal toxicity profile, is now available.Objectives. To evaluate our initial experience of TAF use at Groote Schuur Hospital, Cape Town.Methods. We retrospectively reviewed patients with HBV mono-infection and HIV-HBV co-infection who were initiated on TAF since 2018. We recorded all relevant demographic, serological, virological and biochemical data from patient records. Adherence was documented by pill collection at the pharmacy.Results. A total of 26 patients were included in the evaluation, median (interquartile range (IQR)) age 48 (39 - 51) years, 73% (n=19) male, 27% (n=7) hepatitis B e-antigen-positive, and 46% (n=12) HIV co-infected. The median (IQR) duration of treatment with TAF was 13 (9 - 15) months. The median (IQR) baseline creatinine level was 180 (130 - 227) µmol/L, with significant improvement at 12 months, 122 (94 - 143) µmol/L; p=0.017. Reflecting this change, the estimated glomerular filtration rate improved significantly from baseline to month 12 (42 (25 - 52) and 51 (48 - 68) mL/min/1.73 m2, respectively; p=0.023). Similarly, serum alanine aminotransferase (ALT) normalised from a baseline of 33 (18 - 52) to 18 (15 - 24) U/L at month 12 (p=0.012). HBV DNA viral load also declined, from a baseline of log10 4.04 (2.5 - 7.8) IU/mL to a median of <log10 1.3 IU/mL at month 12. HIV viral load was less than the lower level of quantification at months 6 and 12.Conclusions. TAF was well tolerated, with stable and significantly improving kidney function throughout a 12-month follow-up period. Serum ALT normalised, mirrored by declining HBV viral load. HIV viral load remained undetectable at 6 and 12 months

Where are you at? Re‐engaging bioregional ideas and what they offer geography

Bioregionalism was popularised in the 1970s back to the land movement. It is distinguished from other forms of environmentalism through the spatial imaginary of a bioregion as the scale for environmental action and regenerative living. Bioregional thought has been widely critiqued by geographers for its potentially deterministic understanding of the relationship between place and culture. This paper argues that bioregionalism is less of a homogenous movement and more of a discursive forum that houses a spectrum of perspectives. We identify three key tendencies within bioregional thought, an ontological tendency, a critical tendency and a processual tendency. Each tendency is rooted in different spatial imaginaries, and generates different axiologies and strategies of change. We argue that contemporary processual tendencies in bioregional thought are productive for geographers considering questions of (1) materiality, agency and place, (2) politics, ethics and place, and (3) acting in place for urgent and ethical change

Preserved rapid conceptual processing of emotional expressions despite reduced neuropsychological performance following traumatic brain injury

Objective: Emotional empathy is critical to successful social interactions and is often compromised after traumatic brain injury (TBI). Using the Emostroop task, we investigated whether adults with moderate to severe TBI (N = 26) have problems with rapid conceptual processing of emotional stimuli compared with controls (N = 30). Further, we investigated whether rapid conceptual processing of emotions relates to emotion recognition and emotional empathy. Method: In the Emostroop task, participants categorize emotional words (e.g., joyous, furious, and woeful) into three emotion categories: happy, sad, and angry. Each word is superimposed onto an image of a face, which expresses an emotion that is congruent to the word (congruent condition), incongruent to the word (incongruent condition), or is neutral (neutral condition). Slowed responding in the incongruent condition (interference) and speeded responding in the congruent condition (facilitation) indicates rapid conceptual processing of the faces. Participants also completed an emotion perception task, an empathy questionnaire (the BEES) and neuropsychological tests measuring processing speed, working memory, and executive function. Results: Contrary to our hypotheses, we found that rapid conceptual processing of emotional faces was preserved in people with TBI, despite diminished neuropsychological performance, emotion recognition, emotional empathy, and slowed responding. Further, the Emostroop effect was not correlated with self-reported emotional empathy or with emotion recognition. Conclusions: We conclude that in people with TBI, reduced empathy may be explained by processes downstream of the initial rapid conceptual processing of emotional information, such as flexibly attending and responding to this information in a goal-directed manner in complex environments

A systematic review of strategies to recruit and retain primary care doctors

Background There is a workforce crisis in primary care. Previous research has looked at the reasons underlying recruitment and retention problems, but little research has looked at what works to improve recruitment and retention. The aim of this systematic review is to evaluate interventions and strategies used to recruit and retain primary care doctors internationally. Methods A systematic review was undertaken. MEDLINE, EMBASE, CENTRAL and grey literature were searched from inception to January 2015.Articles assessing interventions aimed at recruiting or retaining doctors in high income countries, applicable to primary care doctors were included. No restrictions on language or year of publication. The first author screened all titles and abstracts and a second author screened 20%. Data extraction was carried out by one author and checked by a second. Meta-analysis was not possible due to heterogeneity. Results 51 studies assessing 42 interventions were retrieved. Interventions were categorised into thirteen groups: financial incentives (n=11), recruiting rural students (n=6), international recruitment (n=4), rural or primary care focused undergraduate placements (n=3), rural or underserved postgraduate training (n=3), well-being or peer support initiatives (n=3), marketing (n=2), mixed interventions (n=5), support for professional development or research (n=5), retainer schemes (n=4), re-entry schemes (n=1), specialised recruiters or case managers (n=2) and delayed partnerships (n=2). Studies were of low methodological quality with no RCTs and only 15 studies with a comparison group. Weak evidence supported the use of postgraduate placements in underserved areas, undergraduate rural placements and recruiting students to medical school from rural areas. There was mixed evidence about financial incentives. A marketing campaign was associated with lower recruitment. Conclusions This is the first systematic review of interventions to improve recruitment and retention of primary care doctors. Although the evidence base for recruiting and care doctors is weak and more high quality research is needed, this review found evidence to support undergraduate and postgraduate placements in underserved areas, and selective recruitment of medical students. Other initiatives covered may have potential to improve recruitment and retention of primary care practitioners, but their effectiveness has not been established

Image informatics strategies for deciphering neuronal network connectivity

Brain function relies on an intricate network of highly dynamic neuronal connections that rewires dramatically under the impulse of various external cues and pathological conditions. Among the neuronal structures that show morphologi- cal plasticity are neurites, synapses, dendritic spines and even nuclei. This structural remodelling is directly connected with functional changes such as intercellular com- munication and the associated calcium-bursting behaviour. In vitro cultured neu- ronal networks are valuable models for studying these morpho-functional changes. Owing to the automation and standardisation of both image acquisition and image analysis, it has become possible to extract statistically relevant readout from such networks. Here, we focus on the current state-of-the-art in image informatics that enables quantitative microscopic interrogation of neuronal networks. We describe the major correlates of neuronal connectivity and present workflows for analysing them. Finally, we provide an outlook on the challenges that remain to be addressed, and discuss how imaging algorithms can be extended beyond in vitro imaging studies