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The linear instability of a vortex ring with swirl with Gaussian distributions of azimuthal vorticity and velocity in its core is studied by direct numerical simulation. The numerical study is carried out in two steps: first, an axisymmetric simulation of the Navier–Stokes equations is performed to obtain the quasi-steady state that forms a base flow; then, the equations are linearized around this base flow and integrated for a sufficiently long time to obtain the characteristics of the most unstable mode. It is shown that the vortex rings are subjected to curvature instability as predicted analytically by Blanco-Rodríguez & Le Dizès (J. Fluid Mech., vol. 814, 2017, pp. 397–415). Both the structure and the growth rate of the unstable modes obtained numerically are in good agreement with the analytical results. However, a small overestimation (e.g. 22 % for a curvature instability mode) by the theory of the numerical growth rate is found for some instability modes. This is most likely due to evaluation of the critical layer damping which is performed for the waves on axisymmetric line vortices in the analysis. The actual position of the critical layer is affected by deformation of the core due to the curvature effect; as a result, the damping rate changes since it is sensitive to the position of the critical layer. Competition between the curvature and elliptic instabilities is also investigated. Without swirl, only the elliptic instability is observed in agreement with previous numerical and experimental results. In the presence of swirl, sharp bands of both curvature and elliptic instabilities are obtained for
is the vortex core radius and
the ring radius, while the elliptic instability dominates for
. New types of instability mode are also obtained: a special curvature mode composed of three waves is observed and spiral modes that do not seem to be related to any wave resonance. The curvature instability is also confirmed by direct numerical simulation of the full Navier–Stokes equations. Weakly nonlinear saturation and subsequent decay of the curvature instability are also observed.
The rise of additive manufacturing (AM) has enabled the rapid production of complex part geometries across multiple material domains. To date, however, AM of inorganic semiconductor materials has not been fully realized due to the difficulty of forming single-crystal materials with traditional AM processes. Here, we demonstrate a novel semiconductor synthesis method using a combination of liquid and gas precursors to additively print gallium nitride. Growth rates of 1–2 µm/min are demonstrated in printed regions while maintaining epitaxial alignment with the substrate. We also outline critical variables for the future development, improvement, and implementation of the proposed process.
Fasciola jacksoni is a significant contributor to the health and mortality of Asian elephants, particularly those in Sri Lanka. Despite the impact of fascioliasis on elephant populations, it is a neglected veterinary disease with limited taxonomic understanding. Molecular characterization and phylogenetic analysis of F. jacksoni were carried out to evaluate its suggested basal position in the Fasciolidae. Adult worms were collected during post-mortem of elephants, and eggs were collected from living elephants in National parks across Sri Lanka. Using the mitochondrial genes nicotinamide dehydrogenase subunit 1 (nad1) and cytochrome oxidase subunit 1 (cox1), and a partial 28S ribosomal DNA (28S rDNA), DNA sequences were generated from the F. jacksoni adult and egg material. Maximum likelihood (ML) phylogenetic analyses did not resolve F. jacksoni to be basal to the Fasciolidae. Furthermore, the ML analyses showed that the genus Fasciola was not monophyletic and that F. jacksoni was a sister species to the deer liver fluke Fascioloides magna. A clear framework is required to determine the taxonomic status of F. jacksoni and this current study provides the first detailed application of molecular techniques from multiple hosts across Sri Lanka with the production of reference DNA sequences for this important parasite.
Seroprevalence estimation using cross-sectional serosurveys can be challenging due to inadequate or unknown biological cut-off limits of detection. In recent years, diagnostic assay cut-offs, fixed assay cut-offs and more flexible approaches as mixture modelling have been proposed to classify biological quantitative measurements into a positive or negative status. Our objective was to estimate the prevalence of anti-HCV antibodies among drug users (DU) in France in 2011 using a biological test performed on dried blood spots (DBS) collected during a cross-sectional serosurvey. However, in 2011, we did not have a cut-off value for DBS. We could not use the values for serum or plasma, knowing that the DBS value was not necessarily the same. Accordingly, we used a method which consisted of applying a two-component mixture model with age-dependent mixing proportions using penalised splines. The component densities were assumed to be log-normally distributed and were estimated in a Bayesian framework. Anti-HCV prevalence among DU was estimated at 43.3% in France and increased with age. Our method allowed us to provide estimates of age-dependent prevalence using DBS without having a specified biological cut-off value.
Weaning is a critical transition phase in swine production in which piglets must cope with different stressors that may affect their health. During this period, the prophylactic use of antibiotics is still frequent to limit piglet morbidity, which raises both economic and public health concerns such as the appearance of antimicrobial-resistant microbes. With the interest of developing tools for assisting health and management decisions around weaning, it is key to provide robustness indexes that inform on the animals’ capacity to endure the challenges associated with weaning. This work aimed at developing a modelling approach for facilitating the quantification of piglet resilience to weaning. A total of 325 Large White pigs weaned at 28 days of age were monitored and further housed and fed conventionally during the post-weaning period without antibiotic administration. Body weight and diarrhoea scores were recorded before and after weaning, and blood was sampled at weaning and 1 week later for collecting haematological data. A dynamic model was constructed based on the Gompertz–Makeham law to describe live weight trajectories during the first 75 days after weaning, following the rationale that the animal response is partitioned in two time windows (a perturbation and a recovery window). Model calibration was performed for each animal. Our results show that the transition time between the two time windows, as well as the weight trajectories are characteristic for each individual. The model captured the weight dynamics of animals at different degrees of perturbation, with an average coefficient of determination of 0.99, and a concordance correlation coefficient of 0.99. The utility of the model is that it provides biologically meaningful parameters that inform on the amplitude and length of perturbation, and the rate of animal recovery. Our rationale is that the dynamics of weight inform on the capability of the animal to cope with the weaning disturbance. Indeed, there were significant correlations between model parameters and individual diarrhoea scores and haematological traits. Overall, the parameters of our model can be useful for constructing weaning robustness indexes by using exclusively the growth curves. We foresee that this modelling approach will provide a step forward in the quantitative characterisation of robustness.
Introduction: Prompt defibrillation is critical during paediatric cardiac arrest. The main objective of this systematic review was to determine the initial defibrillation energy dose for ventricular fibrillation (VF) or pulseless ventricular tachycardia (pVT) that is associated with sustained return of spontaneous circulation (ROSC) during paediatric cardiac arrest. Associations between initial defibrillation energy dose with any ROSC, survival and defibrillation-induced complications were also assessed. Methods: A systematic review was performed using four databases (Medline, Embase, Web of Science, Cochrane Library) (PROSPERO: CRD42016036734). Human studies (cohort studies or controlled trials) and animal model studies (controlled trials) of pediatric cardiac arrest involving assessment of external defibrillation energy dosing were considered. The primary outcome was sustained ROSC. Two researchers independently reviewed all the titles and abstracts of the retrieved citations, selected the studies and extracted the data using a standardized template. Risk of bias of human non-randomised studies were assessed using the ROBIN-I tool (formerly ACROBAT-NRSI) tool proposed by the Cochrane Collaboration group. Results: The search strategy identified 14,471 citations of which 232 manuscripts were reviewed. Ten human and 10 animal model studies met the inclusion criteria. Human studies were prospective (n = 6) or retrospective (n = 4) cohort studies and included between 11 and 266 patients (median = 46 patients). Sustained ROSC rates ranged from 0 to 61% (n = 7). No studies reported a statistically significant association between the initial defibrillation energy dose and the rate of sustained ROSC (n = 7) or survival (n = 6). No human studies reported defibrillation-induced complications. Meta-analysis was not considered appropriate due to clinical heterogeneity. The overall risk of bias was moderate. All animal studies were randomized controlled trials with 8 and 52 (median = 27) piglets. ROSC was frequently achieved (more than 85%) with energy dose ranging from 2 to 7 joules/kg (n = 7). The defibrillation threshold varied according to the body weight and appears to be higher in infant models. Conclusion: Defibrillation energy doses and thresholds varied according to the body weight and trended higher for infants. No definitive association between initial defibrillation doses and the outcomes of sustained ROSC or survival could be demonstrated.
Paludification is the most common process of peatland formation in boreal regions. In this study, we investigated the autogenic (e.g., topography) and allogenic (fire and climate) factors triggering paludification in different geomorphological contexts (glaciolacustrine silty-clayey and fluvioglacial deposits) within the Québec black spruce (Picea mariana)–moss boreal forest. Paleoecological analyses were conducted along three toposequences varying from a forest on mineral soil to forested and semi-open peatlands. Plant macrofossil and charcoal analyses were performed on basal peat sections (≤50 cm) and thick forest humus (<40 cm) to reconstruct local vegetation dynamics and fire history involved in the paludification process. Results show that primary paludification started in small topographic depressions after land emergence ca. 8000 cal yr BP within rich fens. Lateral peatland expansion and secondary paludification into adjacent forests occurred between ca. 5100 and 2300 cal yr BP and resulted from low-severity fires during a climatic deterioration. Fires that reduced or eliminated entirely the organic layer promoted the establishment of Sphagnum in microdepressions. Paludification resulted in the decline of some coniferous species such as Abies balsamea and Pinus banksiana. The paleoecological approach along toposequences allowed us to understand the spatiotemporal dynamics of paludification and its impacts on the vegetation dynamics over the Holocene.
The aim of this study was to assess the impact of a urinary tract infection (UTI) management bundle to reduce the treatment of asymptomatic bacteriuria (AB) and to improve the management of symptomatic UTIs.
Before-and-after intervention study.
Consecutive sample of inpatients with positive single or mixed-predominant urine cultures collected and reported while admitted to the hospital.
The UTI management bundle consisted of nursing and prescriber education, modification of the reporting of positive urine cultures, and pharmacists’ prospective audit and feedback. A retrospective chart review of consecutive inpatients with positive urinary cultures was performed before and after implementation of the management bundle.
Prior to the implementation of the management bundle, 276 patients were eligible criteria for chart review. Of these 276 patients, 165 (59·8%) were found to have AB; of these 165 patients with AB, 111 (67·3%) were treated with antimicrobials. Moreover, 268 patients met eligibility criteria for postintervention review. Of these 268, 133 patients (49·6%) were found to have AB; of these 133 with AB, 22 (16·5%) were treated with antimicrobials. Thus, a 75·5% reduction of AB treatment was achieved. Educational components of the bundle resulted in a substantial decrease in nonphysician-directed urine sample submission. Adherence to a UTI management algorithm improved substantially in the intervention period, with a notable decrease in fluoroquinolone prescription for empiric UTI treatment.
A UTI management bundle resulted in a dramatic improvement in the management of urinary tract infection, particularly a reduction in the treatment of AB and improved management of symptomatic UTI.
The deformation of elementary fluid volumes by velocity gradients is a key process for scalar mixing, chemical reactions and biological processes in flows. Whilst fluid deformation in unsteady, turbulent flow has gained much attention over the past half-century, deformation in steady random flows with complex structure – such as flow through heterogeneous porous media – has received significantly less attention. In contrast to turbulent flow, the steady nature of these flows constrains fluid deformation to be anisotropic with respect to the fluid velocity, with significant implications for e.g. longitudinal and transverse mixing and dispersion. In this study we derive an ab initio coupled continuous-time random walk (CTRW) model of fluid deformation in random steady three-dimensional flow that is based upon a streamline coordinate transform which renders the velocity gradient and fluid deformation tensors upper triangular. We apply this coupled CTRW model to several model flows and find that these exhibit a remarkably simple deformation structure in the streamline coordinate frame, facilitating solution of the stochastic deformation tensor components. These results show that the evolution of longitudinal and transverse fluid deformation for chaotic flows is governed by both the Lyapunov exponent and power-law exponent of the velocity probability distribution function at small velocities, whereas algebraic deformation in non-chaotic flows arises from the intermittency of shear events following similar dynamics as that for steady two-dimensional flow.
We study the mixing dynamics of solute blobs in the flow through saturated heterogeneous porous media. As the solute plume is advected through a heterogeneous porous medium it suffers a series of deformations that determine its mixing with the ambient fluid through diffusion. Key questions are the relation between the spatial disorder and the mixing dynamics and the effect of the initial solute distribution. To address these questions, we formulate the advection–diffusion problem in a coordinate system that moves and rotates along streamlines of the steady flow field. The impact of the medium heterogeneity is quantified systematically within a stochastic modelling approach. For a simple shear flow, the maximum concentration of a blob decays asymptotically as
. For heterogeneous porous media, the mixing of the solute blob is determined by the random sampling of flow and deformation heterogeneity along trajectories, a mechanism different from persistent shear. We derive explicit perturbation theory expressions for stretching-enhanced solute mixing that relate the medium structure and mixing behaviour. The solution is valid for moderate heterogeneity. The random sampling of shear along trajectories leads to a
decay of the maximum concentration as opposed to an equivalent homogeneous medium, for which it decays as
In 2015, the United Nations High Commissioner for Refugees started a process of mental health capacity building in refugee primary health care settings in seven countries in Sub-Saharan Africa, ultimately aiming to decrease the treatment gap of mental, neurological and substance use (MNS) conditions in these operations. In 2015 and 2016, a specialized non-governmental organization, the War Trauma Foundation, trained 619 staff with the mental health gap action programme (mhGAP) Humanitarian Intervention Guide (HIG), a tool designed to guide clinical decision making in humanitarian settings.
This paper describes the results of a process evaluation of a real-life implementation project by an external consultant, one and a half years after starting the programme.
The mhGAP-HIG capacity building efforts had various effects contributing to the integration of mental health in refugee primary health care. Facility-and community-based staff reported strengthened capacities to deliver mental health and psychosocial support interventions as well as changes in their attitude towards people suffering from MNS conditions. Service delivery and collaboration amongst different intervention levels improved. The scarcity of specialized staff in these settings was a major barrier, hindering the setting-up of supervision mechanisms.
Mental health training of non-specialized staff in complex humanitarian settings is feasible and can lead to increased competency of providers. However, capacity building is a ‘process’ and not an ‘event’ and mhGAP trainings are only one element in a spectrum of activities aimed at integrating mental health into general health care. Regular supervision and continuing on-the-job training are in fact critical to ensure sustainability.
Clear policies regarding sexual expression, sexual behaviour and related decision-making assist in ensuring that the rights of people with mental disorder or intellectual disability are upheld, and that staff know how to react to situations consistently and lawfully without interfering on the basis of their own moral judgements or personal beliefs. Sensitive and holistic planning of care that complies with domestic law, international human rights law and statutory guidance is necessary to complement such policies. Non-intimate physical contact, masturbation, sexual relationships, contraception, sterilisation and vasectomy, pregnancy, termination of pregnancy, sexual dysfunction, parenthood, marriage and civil partnership, divorce, prostitution, pornography, and sex aids and toys are all matters that may properly be part of care planning.
•Understand the limited legal basis for the formulation of policies and rules concerning sexual expression, sexual behaviour and related decision-making by people with mental disorder or intellectual disability
•Be able to formulate policies concerning sexual matters as they relate to people with mental disorder or intellectual disability
•Be able to plan care for psychiatric patients and community service users balancing their rights to sexual fulfilment with the protection of their own welfare and the protection of others
The links between low socioeconomic status and poor health are well established, yet despite adversity, some individuals with low socioeconomic status appear to avoid these negative consequences through adaptive coping. Previous research found a set of strategies, called shift-and-persist (shifting the self to stressors while persisting by finding meaning), to be particularly adaptive for individuals with low socioeconomic status, who typically face more uncontrollable stressors. This study tested (a) whether perceived social status, similar to objective socioeconomic status, would moderate the link between shift-and-persist and health, and (b) whether a specific uncontrollable stressor, unfair treatment, would similarly moderate the health correlates of shift-and-persist. A sample of 308 youth (Meanage = 13.0, range 8–17), physician diagnosed with asthma, completed measures of shift-and-persist, unfair treatment, asthma control, and quality of life in the lab, and 2 weeks of daily diaries about their asthma symptoms. Parents reported on perceived family social status. Results indicated that shift-and-persist was associated with better asthma profiles, only among youth from families with lower (vs. higher) parent-reported perceived social status. Shift-and-persist was also associated with better asthma profiles, only among youth who experienced more (vs. less) unfair treatment. These findings suggest that the adaptive values of coping strategies for youth with asthma depend on the family's perceived social status and on the stressor experienced.
A majority of transplanted organs come from donors after brain death (BD). Renal grafts from these donors have higher delayed graft function and lower long-term survival rates compared to living donors. We designed a novel porcine BD model to better delineate the incompletely understood inflammatory response to BD, hypothesizing that adhesion molecule pathways would be upregulated in BD.
Animals were anesthetized and instrumented with monitors and a balloon catheter, then randomized to control and BD groups. BD was induced by inflating the balloon catheter and animals were maintained for 6 hours. RNA was extracted from kidneys, and gene expression pattern was determined.
In total, 902 gene pairs were differently expressed between groups. Eleven selected pathways were upregulated after BD, including cell adhesion molecules.
These results should be confirmed in human organ donors. Treatment strategies should target involved pathways and lessen the negative effects of BD on transplantable organs.
People with mental disorder and intellectual disability have the same rights to sexual expression as other people, albeit that in some cases a lack of capacity may require curtailment of those rights and regard must be had to protecting the vulnerable. Furthermore, the formation or maintenance of sexual relations, or the attainment of sexual fulfilment, may assist in the maintenance or restoration of mental health or well-being. This article demonstrates how the courts in England and Wales, applying statute law and judicial precedent, are largely supportive of the rights of people with mental disorder or intellectual disability to make decisions about sexual expression, sexual relationships and related matters, notwithstanding some societal and staff attitudes that act to prevent them fulfilling their sexual needs and making decisions about sexual and reproductive matters.
•Understand the underlying principles that apply to the exercise of their sexual rights by people with mental disorder or intellectual disability
•Understand some of the obstacles to the exercise of sexual rights by people with mental disorder or intellectual disability
•Understand the statute and case law that apply to the exercise of sexual rights by people with mental disorder or intellectual disability
Hill (Twin Research and Human Genetics, Vol. 21, 2018, 84–88) presented a critique of our recently published paper in Cell Reports entitled ‘Large-Scale Cognitive GWAS Meta-Analysis Reveals Tissue-Specific Neural Expression and Potential Nootropic Drug Targets’ (Lam et al., Cell Reports, Vol. 21, 2017, 2597–2613). Specifically, Hill offered several interrelated comments suggesting potential problems with our use of a new analytic method called Multi-Trait Analysis of GWAS (MTAG) (Turley et al., Nature Genetics, Vol. 50, 2018, 229–237). In this brief article, we respond to each of these concerns. Using empirical data, we conclude that our MTAG results do not suffer from ‘inflation in the FDR [false discovery rate]’, as suggested by Hill (Twin Research and Human Genetics, Vol. 21, 2018, 84–88), and are not ‘more relevant to the genetic contributions to education than they are to the genetic contributions to intelligence’.
Late prehistoric archaeological research in Myanmar is in a phase of rapid expansion. Recent work by the Mission Archéologique Française au Myanmar aims to establish a reliable Neolithic to Iron Age culture-historical sequence, which can then be compared to surrounding regions of Southeast Asia. Excavations at Nyaung'gan and Oakaie in central Myanmar have provided 52 new AMS dates, which allow the creation of Myanmar's first reliable prehistoric radiometric chronology. They have also identified the Neolithic to Bronze Age transition in central Myanmar, which is of critical importance in understanding long-range interactions at the national, regional and inter-regional level. This research provides the first significant step towards placing late prehistoric Myanmar in its global context.