3,004 research outputs found
Bayesian parameter estimation for characterising mobile ion vacancies in perovskite solar cells
To overcome the challenges associated with poor temporal stability of
perovskite solar cells, methods are required that allow for fast iteration of
fabrication and characterisation, such that optimal device performance and
stability may be actively pursued. Currently, establishing the causes of
underperformance is both complex and time-consuming, and optimisation of device
fabrication thus inherently slow. Here, we present a means of computational
device characterisation of mobile halide ion parameters from room temperature
current-voltage (J-V) measurements only, requiring hours of
computation on basic computing resources. With our approach, the physical
parameters of the device may be reverse modelled from experimental J-V
measurements. In a drift-diffusion model, the set of coupled drift-diffusion
partial differential equations cannot be inverted explicitly, so a method for
inverting the drift-diffusion simulation is required. We show how Bayesian
Parameter Estimation (BPE) coupled with a drift-diffusion perovskite solar cell
model can determine the extent to which device parameters affect performance
measured by J-V characteristics. Our method is demonstrated by investigating
the extent to which device performance is influenced by mobile halide ions for
a specific fabricated device. The ion vacancy density and diffusion
coefficient were found to be precisely characterised for both simulated
and fabricated devices. This result opens up the possibility of pinpointing
origins of degradation by finding which parameters most influence device J-V
curves as the cell degrades
The effects of 8Â weeks of inspiratory muscle training on the balance of healthy older adults: a randomized, double-blind, placebo-controlled study.
To examine the effects of 8-week unsupervised, home-based inspiratory muscle training (IMT) on the balance and physical performance of healthy older adults. Fifty-nine participants (74 ± 6 years) were assigned randomly in a double-blinded fashion to either IMT or sham-IMT, using a pressure threshold loading device. The IMT group performed 30-breath twice daily at ~50% of maximal inspiratory pressure (MIP). The sham-IMT group performed 60-breaths once daily at ~15% MIP; training was home-based and unsupervised, with adherence self-reported through training diaries. Respiratory outcomes were assessed pre- and postintervention, including forced vital capacity, forced expiratory volume, peak inspiratory flow rate (PIFR), MIP, and inspiratory peak power. Balance and physical performance outcomes were measured using the shortened version of the Balance Evaluation System test (mini-BEST), Biodex® postural stability test, timed up and go, five sit-to-stand, isometric "sit-up" and Biering-Sørensen tests. Between-group effects were examined using two-way repeated measures ANOVA, with Bonferroni correction. After 8-week, the IMT group demonstrated greater improvements (P ≤ 0.05) in: PIFR (IMT = 0.9 ± 0.3 L sec-1 ; sham-IMT = 0.3 L sec-1 ); mini-BEST (IMT = 3.7 ± 1.3; sham-IMT = 0.5 ± 0.9) and Biering-Sørensen (IMT = 62.9 ± 6.4 sec; sham-IMT = 24.3 ± 1.4 sec) tests. The authors concluded that twice daily unsupervised, home-based IMT is feasible and enhances inspiratory muscle function and balance for community-dwelling older adults
Genomic variant sharing: a position statement.
Sharing de-identified genetic variant data is essential for the practice of genomic medicine and is demonstrably beneficial to patients. Robust genetic diagnoses that inform medical management cannot be made accurately without reference to genetic test results from other patients, as well as population controls. Errors in this process can result in delayed, missed or erroneous diagnoses, leading to inappropriate or missed medical interventions for the patient and their family. The benefits of sharing individual genetic variants, and the harms of not sharing them, are numerous and well-established. Databases and mechanisms already exist to facilitate deposition and sharing of pseudonomised genetic variants, but clarity and transparency around best practice is needed to encourage widespread use, prevent inconsistencies between different communities, maximise individual privacy and ensure public trust. We therefore recommend that widespread sharing of a small number of individual genetic variants associated with limited clinical information should become standard practice in genomic medicine. Information robustly linking genetic variants with specific conditions is fundamental biological knowledge, not personal information, and therefore should not require consent to share. For additional case-level detail about individual patients or more extensive genomic information, which is often essential for clinical interpretation, it may be more appropriate to use a controlled-access model for data sharing, with the ultimate aim of making as much information as open and de-identified as possible with appropriate consent
Acute Cholecystitis Is a Common Complication after Allogeneic Stem Cell Transplantation and Is Associated with the Use of Total Parenteral Nutrition
AbstractThe incidence and risk factors for acute cholecystitis after allogeneic hematopoietic stem cell transplantation (HSCT) are not well defined. Of 644 consecutive adult transplants performed at our institution between 2001 and 2011, acute cholecystitis occurred in the first year of transplant in 32 patients (5.0%). We conducted 2 retrospective case-control studies of this population to determine risk factors for cholecystitis after HSCT and to evaluate the performance of different methods of imaging to diagnosis cholecystitis in patients undergoing HSCT compared with non-HSCT patients. In the HSCT population, development of cholecystitis was associated with an increased 1-year overall mortality rate (62.5% versus 19.8%, P < .001). The risk of developing cholecystitis was higher in patients who received total parenteral nutrition (TPN) (adjusted odds ratio, 3.41; PÂ = .009). There was a trend toward more equivocal abdominal ultrasound findings in HSCT recipients with acute cholecystitis compared with nontransplant patients (50.0% versus 30.6%, PÂ = .06). However, hepatobiliary iminodiacetic acid (HIDA) scans were definitively positive for acute cholecystitis in most patients in both populations (80.0% of HSCT recipients versus 77.4% of control subjects, PÂ = .82). In conclusion, acute cholecystitis is a common early complication of HSCT, the risk is increased in patients who receive TPN, and it is associated with high 1-year mortality. In HSCT recipients with findings suggestive of acute cholecystitis, especially those receiving TPN, early use of HIDA scan may be considered over ultrasound
The crime drop and the security hypothesis
Major crime drops were experienced in the United States and most other industrialised countries for a decade from the early to mid-1990s. Yet there is little agreement over explanation or lessons for policy. Here it is proposed that change in the quantity and quality of security was a key driver of the crime drop. From evidence relating to vehicle theft in two countries it is concluded that electronic immobilisers and central locking were particularly effective. It is suggested that reduced car theft may have induced drops in other crime including violence. From this platform a broader security hypothesis, linked to routine activity and opportunity theory, is outlined
An economic evaluation of expanding hookworm control strategies to target the whole community.
BACKGROUND: The WHO treatment guidelines for the soil-transmitted helminths (STH) focus on targeting children for the control of morbidity induced by heavy infections. However, unlike the other STHs, the majority of hookworm infections are harboured by adults. This untreated burden may have important implications for controlling both hookworm's morbidity and transmission. This is particularly significant in the context of the increased interest in investigating STH elimination strategies. METHODS: We used a deterministic STH transmission model and parameter estimates derived from field epidemiological studies to evaluate the impact of child-targeted (2-14 year olds) versus community-wide treatment against hookworm in terms of preventing morbidity and the timeframe for breaking transmission. Furthermore, we investigated how mass treatment may influence the long-term programmatic costs of preventive chemotherapy for hookworm. RESULTS: The model projected that a large proportion of the overall morbidity due to hookworm was unaffected by the current child-targeted strategy. Furthermore, driving worm burdens to levels low enough to potentially break transmission was only possible when using community-wide treatment. Due to these projected reductions in programme duration, it was possible for community-wide treatment to generate cost savings - even if it notably increases the annual distribution costs. CONCLUSIONS: Community-wide treatment is notably more cost-effective for controlling hookworm's morbidity and transmission than the current child-targeted strategies and could even be cost-saving in many settings in the longer term. These calculations suggest that it is not optimum to treat using the same treatment strategies as other STH. Hookworm morbidity and transmission control require community-wide treatment
Self-stigma in PTSD: Prevalence and correlates
Self-stigma is the internalization of negative societal stereotypes about those with mental illnesses. While self-stigma has been carefully characterized in severe mental disorders, like schizophrenia, the field has yet to examine the prevalence and correlates of self-stigma in post-traumatic stress disorder (PTSD). Thus, we assessed self-stigma in veterans diagnosed with PTSD and compared with veterans with schizophrenia. We further examined associations between PTSD, depressive symptoms and self-stigma in the PTSD sample. Data came from two larger studies of people with PTSD (n = 46) and schizophrenia-spectrum disorders (n = 82). All participants completed the Internalized Stigma of Mental Illness Scale (ISMIS). Results revealed that people with schizophrenia report more experiences of discrimination as a result of stigma than do those with PTSD, but these diagnostic groups did not differ for other subscales. In the PTSD group, feelings of alienation positively correlated with PTSD and depressive symptoms; other subscales positively correlated with depressive symptoms only. Taken together, results suggest a significant level of self-stigma exists among veterans with PTSD, and that self-stigma has an effect on PTSD and commonly comorbid symptoms, like depression. Future work should investigate whether current self-stigma interventions for other groups could be applicable for those with PTSD
The common vaginal commensal bacterium Ureaplasma parvum is associated with chorioamnionitis in extreme preterm labour
Contrasting Metacognitive, Social Cognitive and Alexithymia Profiles in Adults with Borderline Personality Disorder, Schizophrenia and Substance Use Disorder
Deficits in the ability to recognize and think about mental states are broadly understood to be a root cause of dysfunction in Borderline Personality Disorder (PD). This study compared the magnitude of those deficits relative to other forms of serious mental illness or psychiatric conditions. Assessments were performed using the metacognition assessment scale-abbreviated (MAS-A), emotion recognition using the Bell Lysaker Emotion Recognition Test and alexithymia using the Toronto Alexithymia Scale among adults with schizophrenia (n = 65), Borderline PD (n = 34) and Substance Use disorder without psychosis or significant Borderline traits (n = 32). ANCOVA controlling for age revealed the Borderline PD group had significantly greater levels of metacognitive capacity on the MAS-A than the schizophrenia group and significantly lower levels of metacognitive capacity than the Substance Use group. Multiple comparisons revealed the Borderline PD group had significantly higher self-reflectivity and awareness of the other's mind than the schizophrenia group but lesser mastery and decentration on the MAS-A than substance use group, after controlling for self-report of psychopathology and overall number of PD traits. The Borderline PD and Schizophrenia group had significantly higher levels of alexithymia than the substance use group. No differences were found for emotion recognition. Results suggest metacognitive functioning is differentially affected in different mental disorders
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