Stark shift and electric-field-induced dissociation of excitons in monolayer MoS2 and hBN/MoS2 heterostructures

Efficient conversion of photons into electrical current in two-dimensional semiconductors requires, as a first step, the dissociation of the strongly bound excitons into free electrons and holes. Here we calculate the dissociation rates and energy shift of excitons in monolayer MoS2 as a function of an applied in-plane electric field. The dissociation rates are obtained as the inverse lifetime of the resonant states of a two-dimensional hydrogenic Hamiltonian which describes the exciton within the Mott-Wannier model. The resonances are computed using complex scaling, and the effective masses and screened electron-hole interaction defining the hydrogenic Hamiltonian are computed from first principles. For field strengths above 0.1 V/nm the dissociation lifetime is shorter than 1 ps, which is below the lifetime associated with competing decay mechanisms. Interestingly, encapsulation of the MoS2 layer in just two layers of hexagonal boron nitride (hBN), enhances the dissociation rate by around one order of magnitude due to the increased screening. This shows that dielectric engineering is an effective way to control exciton lifetimes in two-dimensional materials

Predictive values of lung cancer alarm symptoms in the general population: a nationwide cohort study

We aimed to firstly determine the 1-year predictive values of lung cancer alarm symptoms in the general population and to analyse the proportion of alarm symptoms reported prior to diagnosis, and secondly analyse how smoking status and reported contact with general practitioners (GPs) regarding lung cancer alarm symptoms influence the predictive values. The study was a nationwide prospective cohort study of 69,060 individuals aged ≥40 years, randomly selected from the Danish population. Using information gathered in a survey regarding symptoms, lifestyle and healthcare-seeking together with registry information on lung cancer diagnoses in the subsequent year, we calculated the predictive values and likelihood ratios of symptoms that might be indicative of lung cancer. Furthermore, we analysed how smoking status and reported contact with GPs regarding the alarm symptoms affected the predictive values. We found that less than half of the patients had reported an alarm symptom six months prior to lung cancer diagnosis. The positive predictive values of the symptoms were generally very low, even for patients reporting GP contact regarding an alarm symptom. The highest predictive values were found for dyspnoea, hoarseness, loss of appetite and for current heavy smokers. The negative predictive values were high, all close to 100%. Given the low positive predictive values, our findings emphasise that diagnostic strategies should not focus on single, specific alarm symptoms, but should perhaps focus on different clusters of symptoms. For patients not experiencing alarm symptoms, the risk of overlooking lung cancer is very low.</p

The Computational 2D Materials Database: High-Throughput Modeling and Discovery of Atomically Thin Crystals

We introduce the Computational 2D Materials Database (C2DB), which organises a variety of structural, thermodynamic, elastic, electronic, magnetic, and optical properties of around 1500 two-dimensional materials distributed over more than 30 different crystal structures. Material properties are systematically calculated by state-of-the art density functional theory and many-body perturbation theory (G$_0\!$W$\!_0$ and the Bethe-Salpeter Equation for $\sim$200 materials) following a semi-automated workflow for maximal consistency and transparency. The C2DB is fully open and can be browsed online or downloaded in its entirety. In this paper, we describe the workflow behind the database, present an overview of the properties and materials currently available, and explore trends and correlations in the data. Moreover, we identify a large number of new potentially synthesisable 2D materials with interesting properties targeting applications within spintronics, (opto-)electronics, and plasmonics. The C2DB offers a comprehensive and easily accessible overview of the rapidly expanding family of 2D materials and forms an ideal platform for computational modeling and design of new 2D materials and van der Waals heterostructures.Comment: Add journal reference and DOI; Minor updates to figures and wordin

Equalities in Freefall? Ontological Insecurity and the long-term Impact of COVID-19 in the Academy

This intervention focuses on the impact of the global crisis resulting from the COVID‐19 pandemic on existing racialized and gendered inequalities within the academy and in particular our discipline of Politics and International Relations. We argue that responses to recent crises within the academy have exacerbated ontological insecurity among minoritized groups, including women. When coupled with increased caring responsibilities the current crises call into question who can be creative and innovative, necessary conditions for knowledge production. While University managers seek to reassure University staff of the temporary nature of COVID‐19 interventions, we argue that the possibilities for progressive leaps at a later state of institutional regeneration is unlikely when efforts to address structural inequalities are sidelined and crisis responses are undertaken which run counter to such work

A 20-year prospective study of mortality and causes of death among hospitalized opioid addicts in Oslo

<p>Abstract</p> <p>Background</p> <p>To study mortality rate and causes of death among all hospitalized opioid addicts treated for self-poisoning or admitted for voluntary detoxification in Oslo between 1980 and 1981, and to compare their mortality to that of the general population.</p> <p>Methods</p> <p>A prospective cohort study was conducted on 185 opioid addicts from all medical departments in Oslo who were treated for either self-poisoning (<it>n </it>= 93, 1980), voluntary detoxification (<it>n </it>= 75, 1980/1981) or both (<it>n </it>= 17). Their median age was 24 years; with a range from 16 to 41, and 53% were males. All deaths that had occurred by the end of 2000 were identified from the Central Population Register. Causes of death were obtained from Statistics Norway. Standardized mortality ratios (SMRs) were computed for mortality, in general, and in particular, for different causes of death.</p> <p>Results</p> <p>During a period of 20 years, 70 opioid addicts died (37.8%), with a standardized mortality ratio (SMR) equal to 23.6 (95% CI, 18.7–29.9). The SMR remained high during the whole period, ranging from 32.4 in the first five-year period, to 13.4 in the last five-year period. There were no significant differences in SMR between self-poisonings and those admitted for voluntarily detoxification. The registered causes of death were accidents (11.4%), suicide (7.1%), cancer (4.3%), cardiovascular disease (2.9%), other violent deaths (2.9%), other diseases (71.4%). Among the 50 deaths classified as other diseases, the category "drug dependence" was listed in the vast majority of cases (37 deaths, 52.9% of the total). SMRs increased significantly for all causes of death, with the other diseases group having the highest SMR; 65.8 (95% CI, 49.9–86.9). The SMR was 5.4 (95% CI, 1.3–21.5) for cardiovascular diseases, and 4.3 (95% CI, 1.4–13.5) for cancer. The SMR was 13.2 (95% CI, 6.6–26.4) for accidents, 10.7 (95% CI, 4.5–25.8) for suicides, and 28.6 (95% CI, 7.1–114.4) for other violent deaths.</p> <p>Conclusion</p> <p>The risk of death among opioid addicts was significantly higher for all causes of death compared with the general population, implying a poor prognosis over a 20-year period for this young patient group.</p

Profitability Level of Fish Farming In Ife-Ijesa Agricultural Development Programme, Osun State, Nigeria

The objective of this paper is to estimate the profitability level of fish farmers in Ife-ijesa zone of Osun State Agricultural Development Programme (OSADEP), Nigeria using standard procedures of structured questionnaires administered to 100 respondents that were randomly selected. The study revealed that fish farming in the Area was male dominated with 89%. For the respondents using earthen 41.3% were range between50-60% and 31.6% of the respondents using concrete were within the range of 50-60years. 70.3% of the respondents using concrete were married and 56.6% of the respondents using earthen were married. 40.5% of the respondents using concrete had tertiary education and 45.2% of the respondents using earthen had tertiary education. 95.7% of the respondents using earthen operate by self-savings and 98.1% of the respondents using concrete also operate by self-saving and the average pond size used was 0.5 hectares. Findings also showed that the estimated average fixed cost and variable cost incurred for all fish farmers were N109.296.43 for the respondents using concrete and N173,473.38 for the respondents using earthen, while gross margin and average farm profit were N108, 718,43 for the respondents using concrete and N172,734.88 for the respondents using earthen per annum respectively

Heart-type Fatty acid-binding protein in Acute Myocardial infarction Evaluation (FAME): Background and design of a diagnostic study in primary care

<p>Abstract</p> <p>Background</p> <p>Currently used biomarkers for cardiac ischemia are elevated in blood plasma after a delay of several hours and therefore unable to detect acute coronary syndrome (ACS) in a very early stage. General practitioners (GPs), however, are often confronted with patients suspected of ACS within hours after onset of complaints. This ongoing study aims to evaluate the added diagnostic value beyond clinical assessment for a rapid bedside test for heart-type fatty-acid binding protein (H-FABP), a biomarker that is detectable as soon as one hour after onset of ischemia.</p> <p>Methods</p> <p>Participating GPs perform a blinded H-FABP rapid bedside test (Cardiodetect^®) in patients with symptoms suggestive of ACS such as chest pain or discomfort at rest. All patients, whether referred to hospital or not, undergo electrocardiography (ECG) and venapunction for a plasma troponin test within 12–36 hours after onset of complaints. A final diagnosis will be established by an expert panel consisting of two cardiologists and one general practitioner (blinded to the H-FABP test result), using all available patient information, also including signs and symptoms. The added diagnostic value of the H-FABP test beyond history taking and physical examination will be determined with receiver operating characteristic curves derived from multivariate regression analysis.</p> <p>Conclusion</p> <p>Reasons for presenting the design of our study include the prevention of publication bias and unacknowledged alterations in the study aim, design or data-analysis. To our knowledge this study is the first to assess the diagnostic value of H-FABP <it>outside </it>a hospital-setting. Several previous hospital-based studies showed the potential value of H-FABP in diagnosing ACS. Up to now however it is unclear whether these results are equally promising when the test is used in primary care. The first results are expected in the end of 2008.</p

Prescriptive variability of drugs by general practitioners

<div><p>Prescription drug spending is growing faster than any other sector of healthcare. However, very little is known about patterns of prescribing and cost of prescribing between general practices. In this study, we examined variation in prescription rates and prescription costs through time for 55 GP surgeries in Northern Ireland Western Health and Social Care Trust. Temporal changes in variability of prescribing rates and costs were assessed using the Mann–Kendall test. Outlier practices contributing to between practice variation in prescribing rates were identified with the interquartile range outlier detection method. The relationship between rates and cost of prescribing was explored with Spearman's statistics. The differences in variability and mean number of prescribing rates associated with the practice setting and socioeconomic deprivation were tested using t-test and <i>F</i>-test respectively. The largest between-practice difference in prescribing rates was observed for Apr-Jun 2015, with the number of prescriptions ranging from 3.34 to 8.36 per patient. We showed that practices with outlier prescribing rates greatly contributed to between-practice variability. The largest difference in prescribing costs was reported for Apr-Jun 2014, with the prescription cost per patient ranging from £26.4 to £64.5. In addition, the temporal changes in variability of prescribing rates and costs were shown to undergo an upward trend. We demonstrated that practice setting and socio-economic deprivation accounted for some of the between-practice variation in prescribing. Rural practices had higher between practice variability than urban practices at all time points. Practices situated in more deprived areas had higher prescribing rates but lower variability than those located in less deprived areas. Further analysis is recommended to assess if variation in prescribing can be explained by demographic characteristics of patient population and practice features. Identification of other factors contributing to prescribing variability can help us better address potential inappropriateness of prescribing.</p></div

There is no age limit for methadone: a retrospective cohort study

BACKGROUND: Data from the US indicates that methadone-maintained populations are aging, with an increase of patients aged 50 or older. Data from European methadone populations is sparse. This retrospective cohort study sought to evaluate the age trends and related developments in the methadone population of Basel-City, Switzerland. METHODS: The study included methadone patients between April 1, 1995 and March 31, 2003. Anonymized data was taken from the methadone register of Basel-City. For analysis of age distributions, patient samples were split into four age categories from '20-29 years' to '50 years and over'. Cross-sectional comparisons were performed using patient samples of 1996 and 2003. RESULTS: Analysis showed a significant increase in older patients between 1996 and 2003 (p < 0.001). During that period, the percentage of patients aged 50 and over rose almost tenfold, while the proportion of patients aged under 30 dropped significantly from 52.8% to 12.3%. The average methadone dose (p < 0.001) and the 1-year retention rate (p < 0.001) also increased significantly. CONCLUSIONS: Findings point to clear trends in aging of methadone patients in Basel-City which are comparable, although less pronounced, to developments among US methadone populations. Many unanswered questions on medical, psychosocial and health economic consequences remain as the needs of older patients have not yet been evaluated extensively. However, older methadone patients, just as any other patients, should be accorded treatment appropriate to their medical condition and needs. Particular attention should be paid to adequate solutions for persons in need of care