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Instrumental-variable (IV) estimation is an essential method for applied researchers across the social and behavioral sciences who analyze randomized control trials marred by noncompliance or leverage partially exogenous treatment variation in observational studies. The potential outcome framework is a popular model to motivate the assumptions underlying the identification of the local average treatment effect (LATE) and to stratify the sample into compliers, always-takers, and never-takers. However, applied research has thus far paid little attention to the characteristics of compliers and noncompliers. Yet, profiling compliers and noncompliers is necessary to understand what subpopulation the researcher is making inferences about and an important first step in evaluating the external validity (or lack thereof) of the LATE estimated for compliers. In this letter, we discuss the assumptions necessary for profiling, which are weaker than the assumptions necessary for identifying the LATE if the instrument is randomly assigned. We introduce a simple and general method to characterize compliers, always-takers, and never-takers in terms of their covariates and provide easy-to-use software in R and STATA that implements our estimator. We hope that our method and software facilitate the profiling of compliers and noncompliers as a standard practice accompanying any IV analysis.
Bilingual children show a number of advantages in the domain of communication. The aim of the current study was to investigate whether differences in interactions are present before productive language skills emerge. For a duration of 5 minutes, 64 parents and their 14-month-old infants explored a decorated room together. The coordination of their behaviors in the modalities of action, language, and gesture was coded. The results showed no differences in interactions across different language statuses. In two additional analyses, we first compared monolinguals and bilinguals with caregivers who shared the same language and culture. Results showed the same pattern of non-difference. Second, we compared bilinguals with caregivers from different cultures. The rate and duration of coordination differed across infants with different cultural backgrounds. The findings suggest that exposure to two languages is not sufficient to explain the previously identified beneficial effects in the communicative interactions of bilingual children.
In this paper, we study the shape and dynamics of helical coherent structures found in the flow field of an annular swirling jet undergoing vortex breakdown. The flow field is studied by means of time-resolved tomographic particle image velocimetry measurements. The obtained flow fields are analysed using both classic and spectral proper orthogonal decomposition. Despite the simple geometrical set-up of the annular jet, the flow field is very complex. Two distinct large-scale helical flow structures are identified: a single and a double helix, both co-rotating with the swirl direction, and it is revealed that these structures are not higher harmonics of each other. The structures have a relatively low energy content which makes it hard to separate them from other dynamics of the flow field, notably turbulent motions. Because of this, classic proper orthogonal decomposition fails to identify both structures properly. Spectral proper orthogonal decomposition, on the other hand, allows them to be identified accurately when the filter size is set at around eight times the precession period. The precession frequencies of the single and double helices correspond to Strouhal numbers of 0.273 and
, respectively. A global stability analysis of the mean flow field shows that these structures correspond to two separate global modes. The precessing frequencies obtained by the stability analysis and the related spatial structures match very well with the experimental observations. The current work extends our knowledge on turbulent vortex breakdown and on mean field global stability theory in general. It leads to the following conclusions. Firstly, single- and double-helix vortex breakdown are both manifestations of global modes. Previous studies have shown that both
modes can coexist in swirling jets. However, the
mode has been identified as a second harmonic of the first mode, while this study identifies both as two independent global modes. Secondly, this work shows that the simultaneous occurrence of multiple helical global modes is possible within a turbulent flow and their shapes and frequencies are very well predicted by mean field stability analysis. The latter finding is of general interest as it applies to a wide class of fluid problems dominated by multiple oscillatory structures.
To characterize the magnitude of virus contamination on personal protective equipment (PPE), skin, and clothing of healthcare workers (HCWs) who cared for patients having acute viral infections.
Prospective observational study.
Acute-care academic hospital.
A total of 59 HCWs agreed to have their PPE, clothing, and/or skin swabbed for virus measurement.
The PPE worn by HCW participants, including glove, face mask, gown, and personal stethoscope, were swabbed with Copan swabs. After PPE doffing, bodies and clothing of HCWs were sampled with Copan swabs: hand, face, and scrubs. Preamplification and quantitative polymerase chain reaction (qPCR) methods were used to quantify viral RNA copies in the swab samples.
Overall, 31% of glove samples, 21% of gown samples, and 12% of face mask samples were positive for virus. Among the body and clothing sites, 21% of bare hand samples, 11% of scrub samples, and 7% of face samples were positive for virus. Virus concentrations on PPE were not statistically significantly different than concentrations on skin and clothing under PPE. Virus concentrations on the personal stethoscopes and on the gowns were positively correlated with the number of torso contacts (P < .05). Virus concentrations on face masks were positively correlated with the number of face mask contacts and patient contacts (P < .05).
Healthcare workers are routinely contaminated with respiratory viruses after patient care, indicating the need to ensure that HCWs complete hand hygiene and use other PPE to prevent dissemination of virus to other areas of the hospital. Modifying self-contact behaviors may decrease the presence of virus on HCWs.
We focused on the Pirin–Pangeon–Thasos carbonate sequence of the Rhodope thrust system, combining Sr isotopes from marble with U–Pb dating of detrital zircons from interlayered schists with outcrop near the villages of Ilindentsi and Petrovo in Bulgaria. The youngest zircon age at Ilindentsi is 266 Ma, i.e. Middle Permian, while the youngest zircon at Petrovo yielded an age of 290 Ma, i.e. Early Permian. Strontium isotopes range from 0.707420 to 0.707653, and are consistent with a Middle Permian maximum depositional age. Middle Permian sedimentation of this carbonate platform most likely occurred along the Eurasian margin rather than the Gondwana margin.
What type of trade agreement is the public willing to accept? Instead of focusing on individual concerns about market access and trade barriers, we argue that specific treaty design and, in particular, the characteristics of the dispute settlement mechanism, play a critical role in shaping public support for trade agreements. To examine this theoretical expectation, we conduct a conjoint experiment that varies diverse treaty-design elements and estimate preferences over multiple dimensions of the Transatlantic Trade and Investment Partnership (TTIP) based on a nationally representative sample in Germany. We find that compared to other alternatives, private arbitration, known as investor-state dispute settlement (ISDS), generates strong opposition to the trade agreement. As the single most important factor, this effect of dispute settlement characteristic is strikingly large and consistent across individuals’ key attributes, including skill levels, information, and national sentiment, among others.
This article explores the role of individuality in Europe's urban past. In so doing, it builds on Georg Simmel's famous article ‘The metropolis and mental life’ as well as recent work especially by Bernard Lahire, Niklas Luhmann and Uwe Schimank. The article brings out key sociological insights and links them to a range of studies by urban historians, which are thus revisited from a fresh angle. The focus is on three key dimensions of the modern city: first, sites of social and cultural life; secondly, politics and government; thirdly, non-humans such as material objects, animals and natural elements.
The hypoactive, hyperactive, and mixed subtypes of delirium differently impact patient management and prognosis, yet the evidence remains sparse. Therefore, we examined the outcome of varying management strategies in the subtypes of delirium.
In this observational cohort study, 602 patients were managed for delirium over 20 days with the following strategies: supportive care alone or in combination with psychotropics, single, dual, or triple+ psychotropic regimens. Cox regression models were calculated for time to remission and benefit rates (BRs) of management strategies.
Generally, the mixed subtype of delirium caused more severe and persistent delirium, and the hypoactive subtype was more persistent than the hyperactive subtype. The subtypes of delirium were similarly predictive for mortality (P = 0.697) and transfer to inpatient psychiatric care (P = 0.320). In the mixed subtype, overall, psychotropic drugs were administered more often (P = 0.016), and particularly triple+ regimens were administered more commonly compared to hypoactive delirium (P = 0.007). Patients on supportive care benefited most, whereas those on triple+ regimens did worst in terms of remission in all groups of hypoactive, hyperactive, and mixed subtypes (BR: 4.59, CI 2.01–10.48; BR: 4.59, CI 1.76–31.66; BR: 3.36, CI 1.73–6.52; all P < 0.05).
Significance of results
The mixed subtype was more persistent to management than the hypoactive and hyperactive subtypes. Delirium management remains controversial and, generally, supportive care benefited patients most. Psychopharmacological management for delirium requires careful choosing of and limiting the number of psychotropics.
Eating behaviours in childhood are considered as risk factors for eating disorder behaviours and diagnoses in adolescence. However, few longitudinal studies have examined this association.
We investigated associations between childhood eating behaviours during the first ten years of life and eating disorder behaviours (binge eating, purging, fasting and excessive exercise) and diagnoses (anorexia nervosa, binge eating disorder, purging disorder and bulimia nervosa) at 16 years.
Data on 4760 participants from the Avon Longitudinal Study of Parents and Children were included. Longitudinal trajectories of parent-rated childhood eating behaviours (8 time points, 1.3–9 years) were derived by latent class growth analyses. Eating disorder diagnoses were derived from self-reported, parent-reported and objectively measured anthropometric data at age 16 years. We estimated associations between childhood eating behaviours and eating disorder behaviours and diagnoses, using multivariable logistic regression models.
Childhood overeating was associated with increased risk of adolescent binge eating (risk difference, 7%; 95% CI 2 to 12) and binge eating disorder (risk difference, 1%; 95% CI 0.2 to 3). Persistent undereating was associated with higher anorexia nervosa risk in adolescent girls only (risk difference, 6%; 95% CI, 0 to 12). Persistent fussy eating was associated with greater anorexia nervosa risk (risk difference, 2%; 95% CI 0 to 4).
Our results suggest continuities of eating behaviours into eating disorders from early life to adolescence. It remains to be determined whether childhood eating behaviours are an early manifestation of a specific phenotype or whether the mechanisms underlying this continuity are more complex. Findings have the potential to inform preventative strategies for eating disorders.
Declaration of interest
C.M.B. reports conflict of interest with Shire (grant recipient, Scientific Advisory Board member) and Pearson and Walker (author, royalty recipient). All other authors have indicated they have no conflicts of interest to disclose.
Since the 1990s, facilities for individuals at putative risk for psychosis have mushroomed and within a very short time have become part of the standard psychiatric infrastructure in many countries. The idea of preventing a severe mental disorder before its exacerbation is laudable, and early data indeed strongly suggested that the sooner the intervention, the better the outcome. In this paper, the authors provide four reasons why they think that early detection or prodromal facilities should be renamed and their treatment targets reconsidered. First, the association between the duration of untreated psychosis and outcome is empirically established but has become increasingly weak over the years. Moreover, its applicability to those who are considered at risk remains elusive. Second, instruments designed to identify future psychosis are prone to many biases that are not yet sufficiently controlled. None of these instruments allows an even remotely precise prognosis. Third, the rate of transition to psychosis in at-risk patients is likely lower than initially thought, and evidence for the success of early intervention in preventing future psychosis is promising but still equivocal. Perhaps most importantly, the treatment is not hope-oriented. Patients are more or less told that schizophrenia is looming over them, which may stigmatize individuals who will never, in fact, develop psychosis. In addition self-stigma has been associated with suicidality and depression. The authors recommend that treatment of help-seeking individuals with mental problems but no established diagnosis should be need-based, and the risk of psychosis should be de-emphasized as it is only one of many possible outcomes, including full remission. Prodromal clinics should not be abolished but should be renamed and restructured. Such clinics exist, but the transformation process needs to be facilitated.