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Nonlinear diffusion equations and curvature conditions in metric measure spaces
No full textThe aim of this paper is to provide new characterizations of the curvature dimension condition in the context of metric measure spaces (X,d,m).
On the geometric side, the authors' new approach takes into account suitable weighted action functionals which provide the natural modulus of K-convexity when one investigates the convexity properties of N-dimensional entropies. On the side of diffusion semigroups and evolution variational inequalities, the authors' new approach uses the nonlinear diffusion semigroup induced by the N-dimensional entropy, in place of the heat flow.
Under suitable assumptions (most notably the quadraticity of Cheeger's energy relative to the metric measure structure) both approaches are shown to be equivalent to the strong CD∗(K,N) condition of Bacher-Sturm
Prediction and memory: A predictive coding account
No full textThe hippocampus is crucial for episodic memory, but it is also involved in online prediction. Evidence suggests that a unitary hippocampal code underlies both episodic memory and predictive processing, yet within a predictive coding framework the hippocampal-neocortical interactions that accompany these two phenomena are distinct and opposing. Namely, during episodic recall, the hippocampus is thought to exert an excitatory influence on the neocortex, to reinstate activity patterns across cortical circuits. This contrasts with empirical and theoretical work on predictive processing, where descending predictions suppress prediction errors to ‘explain away’ ascending inputs via cortical inhibition. In this hypothesis piece, we attempt to dissolve this previously overlooked dialectic. We consider how the hippocampus may facilitate both prediction and memory, respectively, by inhibiting neocortical prediction errors or increasing their gain. We propose that these distinct processing modes depend upon the neuromodulatory gain (or precision) ascribed to prediction error units. Within this framework, memory recall is cast as arising from fictive prediction errors that furnish training signals to optimise generative models of the world, in the absence of sensory data
Environmental factors, human presence and prey interact to explain patterns of tiger presence in Eastern Thailand
No full textThailand is one of the last strongholds for tigers Panthera tigris in mainland Southeast Asia. Evidence suggests heterogeneity in tiger presence in a globally important landscape in Eastern Thailand is potentially influenced by a complex interaction of prey, human presence and environmental conditions. Understanding these dynamics is of considerable importance for the conservation of tigers both in this landscape and elsewhere in their range. In this study, we examine which factors, among prey, human presence and environmental characteristics, best explain tiger presence in the Dong Phayayen–Khao Yai Forest Complex (DPKY). We collated survey data from 56,214 camera trap nights and evaluated the relationship between tiger presence and a suite of five prey, 11 human presence and eight environmental variables. We then used variance partitioning to discern the degree of variance in tiger presence explained by these factors. We documented strong, positive associations with wild boar Sus scrofa presence and prey richness, and strong, negative associations with human settlement density, public roads and presence of poachers. Environmental characteristics explained a greater relative proportion of variance (19.6%) in tiger presence than prey covariates alone (3.1%), particularly confounded with human presence (31.1%). This suggests that environmental variables, especially when accompanied by anthropogenic factors, could be used to model potential tiger occurrence where other data may be lacking. Our approach may be helpful in providing guidance for prioritizing habitat, evaluating the effect of human presence and identifying key prey to provide a foundation for tiger protection and recovery
Spatial structure in Neptune’s 7.90-m stratospheric CH emission, as measured by VLT-VISIR
No full textWe present a comparison of VLT-VISIR images and Keck-NIRC2 images of Neptune, which highlight the coupling between its troposphere and stratosphere. VLT-VISIR images were obtained on September 16th 2008 (UT) at 7.90 μm and 12.27 μm, which are primarily sensitive to 1-mbar CH4 and C2H6 emission, respectively. NIRC2 images in the H band were obtained on October 5th, 6th and 9th 2008 (UT) and sense clouds and haze in the upper troposphere and lower stratosphere (from approximately 600 to 20 mbar). At 7.90 μm, we observe enhancements of CH4 emission in latitude bands centered at approximately 25∘S and 48∘S (planetocentric). Within these zonal bands, tentative detections (<2σ) of discrete hotspots of CH4 emission are also evident at 24∘S, 181∘W and 42∘S, 170∘W. The longitudinal-mean enhancements in the CH4 emission are also latitudinally-coincident with bands of bright (presumably CH4 ice) clouds in the upper troposphere and lower stratosphere evidenced in the H-band images. This suggests the Neptunian troposphere and stratosphere are coupled in these specific regions. This could be in the form of (1) ‘overshoot’ of strong, upwelling plumes and advection of CH4 ice into the lower stratosphere, which subsequently sublimates into CH4 gas and/or (2) generation of waves by plumes impinging from the tropopause below, which impart their energy and heat the lower stratosphere. We favor the former process since there is no evidence of similar smaller-scale morphology in the C2H6 emission, which probes a similar atmospheric level. However, we cannot exclude temperature variations as the source of the morphology observed in CH4 emission. Future, near-infrared imaging of Neptune performed near-simultaneously with future mid-infrared spectral observations of Neptune by the James Webb Space Telescope would allow the coupling of Neptune's troposphere and stratosphere to be confirmed and studied in greater detail
First time mothers’ expectations and experiences of postnatal care in England
No full textPostnatal care is the aspect of maternity care with which women in England are least satisfied.
Little is known about first time mothers’ expectations of postnatal care, or how these
expectations relate to their experiences and appraisal of care. 32 first time mothers took part in a
longitudinal qualitative descriptive study, based on two semi-structured interviews - the first in
pregnancy, and the second 2-3 months after birth. Trajectory analysis was used to identify
thematic patterns in the relationships between postnatal care expectations, needs, experiences
and confidence. Five trajectories were identified, showing that mothers’ satisfaction with
postnatal care and confidence were primarily influenced not by the extent to which their
expectations were met, but the varied extent to which their individual postnatal needs were met.
Rapid and responsive assessment of needs both antenatally and postnatally, and appropriate
adjustment of care, is key in supporting women effectively at this time
How fast can you escape a compact polytope?
No full textThe Continuous Polytope Escape Problem (CPEP) asks whether every trajectory of a linear differential equation initialised within a convex polytope eventually escapes the polytope. We provide a polynomial-time algorithm to decide CPEP for compact polytopes. We also establish a quantitative uniform upper bound on the time required for every trajectory to escape the given polytope. In addition, we establish iteration bounds for termination of discrete linear loops via reduction to the continuous case
Long-term puberty suppression for a non-binary teen
No full textMany TGD young people have a gender identity that does not conform to the standard two options of male or female – they are non-binary. Some non-binary individuals wish for an androgynous body. For those who have not yet progressed through puberty, this can theoretically be achieved via long-term puberty suppression with gonadotrophin releasing hormone agonists (GnRHa). While such treatment might help to ameliorate the gender dysphoria and serious mental health issues commonly seen in TGD young people, it also carries physical health risks and raises various ethical dilemmas. In this Ethics Rounds, we analyze a case that raised issues about maintaining a non-binary gender
Acute malnutrition recovery energy requirements based on mid-upper arm circumference: secondary analysis of feeding program data from 5 countries, Combined Protocol for Acute Malnutrition Study (ComPAS) Stage 1
No full textBackground
Severe and moderate acute malnutrition (SAM and MAM) are currently treated with different food products in separate treatment programs. The development of a unified and simplified treatment protocol using a single food product aims to increase treatment program efficiency and effectiveness. This study, the first stage of the ComPAS trial, sought to assess rate of growth and energy requirements among children recovering from acute malnutrition in order to design a simplified, MUAC-based dosage protocol.
Methods
We obtained secondary data from patient cards of children aged 6–59 months recovering from SAM in outpatient therapeutic feeding programs (TFPs) and from MAM in supplementary feeding programs (SFPs) in five countries in Africa and Asia. We used local polynomial smoothing to assess changes in MUAC and proportional weight gain between clinic visits and assessed their normalized differences for a non-zero linear trend. We estimated energy needs to meet or exceed the growth observed in 95% of visits.
Results
This analysis used data from 5518 patients representing 33942 visits. Growth trends in MUAC and proportional weight gain were not significantly different, each lower at higher MUAC values: MUAC growth averaged 2mm/week at lower MUACs (100 to <110mm) and 1mm/week at higher MUACs (120mm to <125mm); and proportional weight gain declined from 3.9g/kg/day to 2.4g/kg/day across the same MUAC values. In 95% of visits by children with a MUAC 100mm to <125mm who were successfully treated, energy needs could be met or exceeded with 1,000 kilocalories a day.
Conclusion
Two 92g sachets of Ready-to-Use Therapeutic Food (RUTF) (1,000kcal total) is proposed to meet the estimated total energy requirements of children with a MUAC 100mm to <115mm, and one 92g sachet of RUTF (500kcal) is proposed to meet half the energy requirements of children with a MUAC of 115 to <125mm. A simplified, combined protocol may enable a more holistic continuum of care, potentially contributing to increased coverage for children suffering from acute malnutrition
Challenges and opportunities for lung ultrasound in novel Coronavirus disease (COVID-19)
No full textEvidence for HIV-1 cure after CCR5Δ32/Δ32 allogeneic haemopoietic stem-cell transplantation 30 months post analytical treatment interruption: a case report
No full textBackground: The London patient (participant 36 in the IciStem cohort) underwent allogeneic stem-cell transplantation with cells that did not express CCR5 (CCR5Δ32/Δ32); remission was reported at 18 months after analytical treatment interruption (ATI). Here, we present longer term data for this patient (up to 30 months after ATI), including sampling from diverse HIV-1 reservoir sites.
Methods: We used ultrasensitive viral load assays of plasma, semen, and cerebrospinal fluid (CSF) samples to detect HIV-1 RNA. In gut biopsy samples and lymph-node tissue, cell-copy number and total HIV-1 DNA levels were quantified in multiple replicates, using droplet digital PCR (ddPCR) and quantitative real-time PCR. We also analysed the presence of intact proviral DNA using multiplex ddPCR targeting the packaging signal (ψ) and envelope (env). We did intracellular cytokine staining to measure HIV-1-specific T-cell responses. We used low-sensitive and low-avidity antibody assays to measure the humoral response to HIV-1. We predicted the probability of rebound using a mathematical model and inference approach.
Findings: HIV-1 viral load in plasma remained undetectable in the London patient up to 30 months (last tested on March 4, 2020), using an assay with a detection limit of 1 copy per mL. The patient's CD4 count was 430 cells per μL (23·5% of total T cells) at 28 months. A very low-level positive signal for HIV-1 DNA was recorded in peripheral CD4 memory cells at 28 months. The viral load in semen was undetectable in both plasma (lower limit of detection [LLD] <12 copies per mL) and cells (LLD 10 copies per 106 cells) at 21 months. CSF was within normal parameters at 25 months, with HIV-1 RNA below the detection limit (LLD 1 copy per mL). HIV-1 DNA by ddPCR was negative in rectum, caecum, and sigmoid colon and terminal ileum tissue samples at 22 months. Lymph-node tissue from axilla was positive for the long-terminal repeat (33 copies per 106 cells) and env (26·1 copies per 106 cells), negative for ψ and integrase, and negative by the intact proviral DNA assay, at 27 months. HIV-1-specific CD4 and CD8 T-cell responses have remained absent at 27 months. Low-avidity Env antibodies have continued to decline. Mathematical modelling suggests that the probability of remission for life (cure) is 98% in the context of 80% donor chimerism in total HIV target cells and greater than 99% probability of remission for life with 90% donor chimerism.
Interpretation: The London patient has been in HIV-1 remission for 30 months with no detectable replication-competent virus in blood, CSF, intestinal tissue, or lymphoid tissue. Donor chimerism has been maintained at 99% in peripheral T cells. We propose that these findings represent HIV-1 cure