The near-infrared imager and slitless spectrograph for the James Webb Space Telescope. II. Wide field slitless spectroscopy

We acknowledge support from the Natural Sciences and Engineering Research Council of Canada (NSERC) through a variety of its funding programs. This work is in part supported by Canadian Space Agency grant 18JWSTGTO1. C.P., S.R. and K.V. are supported by the Canadian Space Agency under a contract with NRC Herzberg Astronomy and Astrophysics. K.M. acknowledges funding by the Science and Technology Foundation of Portugal (FCT), grants No. IF/00194/2015, PTDC/FIS-AST/28731/2017, UIDB/00099/2020.We present the wide field slitless spectroscopy mode of the NIRISS instrument on the James Webb Space Telescope. This mode employs two orthogonal low-resolution (resolving power ≈150) grisms in combination with a set of six blocking filters in the wavelength range 0.8–2.3 μm to provide a spectrum of almost every source across the field-of-view. When combined with the low background, high sensitivity and high spatial resolution afforded by the telescope, this mode will enable unprecedented studies of the structure and evolution of distant galaxies. We describe the performance of the as-built hardware relevant to this mode and expected imaging and spectroscopic sensitivity. We discuss operational and calibration procedures to obtain the highest quality data. As examples of the observing mode usage, we present details of two planned Guaranteed Time Observations programs: The Canadian NIRISS Unbiased Cluster Survey and The NIRISS Survey for Young Brown Dwarfs and Rogue Planets.Publisher PDFPeer reviewe

Prevalence and Predictors of Persistence of COVID-19 Symptoms in Older Adults: A Single-Center Study

Objectives: Symptom persistence weeks after laboratory-confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) clearance is a relatively common long-term complication of Coronavirus disease 2019 (COVID-19). Little is known about this phenomenon in older adults. The present study aimed at determining the prevalence of persistent symptoms among older COVID-19 survivors and identifying symptom patterns. Design: Cross-sectional study. Setting and Participants: We analyzed data collected in people 65 years and older (n = 165) who were hospitalized for COVID-19 and then admitted to the Day Hospital Post-COVID 19 of the Fondazione Policlinico Universitario “Agostino Gemelli” IRCCS (Rome, Italy) between April and December 2020. All patients tested negative for SARS-CoV-2 and met the World Health Organization criteria for quarantine discontinuation. Measures: Patients were offered multidisciplinary individualized assessments. The persistence of symptoms was evaluated on admission using a standardized questionnaire. Results: The mean age was 73.1 ± 6.2 years (median 72, interquartile range 27), and 63 (38.4%) were women. The average time elapsed from hospital discharge was 76.8 ± 20.3 days (range 25−109 days). On admission, 137 (83%) patients reported at least 1 persistent symptom. Of these, more than one-third reported 1 or 2 symptoms and 46.3% had 3 or more symptoms. The rate of symptom persistence was not significantly different when patients were stratified according to median age. Compared with those with no persistent symptoms, patients with symptom persistence reported a greater number of symptoms during acute COVID-19 (5.3 ± 3.0 vs 3.3 ± 2.0; P < .001). The most common persistent symptoms were fatigue (53.1%), dyspnea (51.5%), joint pain (22.2%), and cough (16.7%). The likelihood of symptom persistence was higher in those who had experienced fatigue during acute COVID-19. Conclusions and Implications: Persistent symptoms are frequently experienced by older adults who have been hospitalized for COVID-19. Follow-up programs should be implemented to monitor and care for long-term COVID-19–related health issues

Multiview classification and dimensionality reduction of scalp and intracranial EEG data through tensor factorisation

Electroencephalography (EEG) signals arise as a mixture of various neural processes that occur in different spatial, frequency and temporal locations. In classification paradigms, algorithms are developed that can distinguish between these processes. In this work, we apply tensor factorisation to a set of EEG data from a group of epileptic patients and factorise the data into three modes; space, time and frequency with each mode containing a number of components or signatures. We train separate classifiers on various feature sets corresponding to complementary combinations of those modes and components and test the classification accuracy of each set. The relative influence on the classification accuracy of the respective spatial, temporal or frequency signatures can then be analysed and useful interpretations can be made. Additionaly, we show that through tensor factorisation we can perform dimensionality reduction by evaluating the classification performance with regards to the number mode components and by rejecting components with insignificant contribution to the classification accuracy

Gaussian Mixture Model of Heart Rate Variability

Heart rate variability (HRV) is an important measure of sympathetic and parasympathetic functions of the autonomic nervous system and a key indicator of cardiovascular condition. This paper proposes a novel method to investigate HRV, namely by modelling it as a linear combination of Gaussians. Results show that three Gaussians are enough to describe the stationary statistics of heart variability and to provide a straightforward interpretation of the HRV power spectrum. Comparisons have been made also with synthetic data generated from different physiologically based models showing the plausibility of the Gaussian mixture parameters

Assessing the Effects of Personal Characteristics and Context on U.S. House Speakers’ Leadership Styles, 1789-2006

Research on congressional leadership has been dominated in recent decades by contextual interpretations that see leaders’ behavior as best explained by the environment in which they seek to exercise leadership—particularly, the preference homogeneity and size of their party caucus. The role of agency is thus discounted, and leaders’ personal characteristics and leadership styles are underplayed. Focusing specifically on the speakers of the U.S. House of Representatives from the first to the 110th Congress, we construct measures of each speaker’s commitment to comity and leadership assertiveness. We find the scores reliable and then test the extent to which a speaker’s style is the product of both political context and personal characteristics. Regression estimates on speakers’ personal assertiveness scores provide robust support for a context-plus-personal characteristics explanation, whereas estimates of their comity scores show that speakers’ personal backgrounds trump context

Academic detailing and adherence to guidelines for Group B streptococci prenatal screening: a randomized controlled trial

BACKGROUND: Clinical practice guidelines (CPGs) recommend universal prenatal screening for Group B Streptococcus (GBS) to identify candidates for intrapartum antibiotic prophylaxis to prevent early onset neonatal GBS infection. Interventions to promote physician adherence to these guidelines are imperative. This study examined the effectiveness of academic detailing (AD) of obstetricians, compared with CPG mailshot and no intervention, on the screening of pregnant women for GBS. METHODS: A randomized controlled clinical trial was conducted in the medical cooperative of Porto Alegre, Brazil. All obstetricians who assisted in a delivery covered by private health insurance managed by the cooperative in the 3 months preceding the study (n = 241) were invited to participate. The obstetricians were randomized to three groups: direct mail (DM, n = 76), AD (n = 76) and control (C, n = 89, no intervention). Those in the DM group were sent guidelines on GBS. The AD group received the guidelines and an educational visit detailing the guidelines, which was conducted by a trained physician. Data on obstetrician age, gender, time since graduation, whether patients received GBS screening during pregnancy, and obstetricians who requested screening were collected for all participant obstetricians for 3 months before and after the intervention, using database from the private health insurance information system. RESULTS: Three months post-intervention, the data showed that the proportion of pregnant women screened for GBS was higher in the AD group (25.4%) than in the DM (15.9%) and C (17.7%) groups (P = 0.023). Similar results emerged when the three groups were taken as a cluster (pregnant women and their obstetricians), but the difference was not statistically significant (Poisson regression, P = 0.108). Additionally, when vaginal deliveries were analyzed separately, the proportion screened was higher in the AD group (75%) than in the DM group (41.9%) and the C group (30.4%) (chi-square, P < 0.001). CONCLUSIONS: The results suggest that AD increased the prevalence of GBS screening in pregnant women in this population

The growth of a culture of evidence-based obstetrics in South Africa: a qualitative case study

<p>Abstract</p> <p>Background</p> <p>While the past two decades have seen a shift towards evidence-based obstetrics and midwifery, the process through which a culture of evidence-based practice develops and is sustained within particular fields of clinical practice has not been well documented, particularly in LMICs (low- and middle-income countries). Forming part of a broader qualitative study of evidence-based policy making, this paper describes the development of a culture of evidence-based practice amongst maternal health policy makers and senior academic obstetricians in South Africa</p> <p>Methods</p> <p>A qualitative case-study approach was used. This included a literature review, a policy document review, a timeline of key events and the collection and analysis of 15 interviews with policy makers and academic clinicians involved in these policy processes and sampled using a purposive approach. The data was analysed thematically.</p> <p>Results</p> <p>The concept of evidence-based medicine became embedded in South African academic obstetrics at a very early stage in relation to the development of the concept internationally. The diffusion of this concept into local academic obstetrics was facilitated by contact and exchange between local academic obstetricians, opinion leaders in international research and structures promoting evidence-based practice. Furthermore the growing acceptance of the concept was stimulated locally through the use of existing professional networks and meetings to share ideas and the contribution of local researchers to building the evidence base for obstetrics both locally and internationally. As a testimony to the extent of the diffusion of evidence-based medicine, South Africa has strongly evidence-based policies for maternal health.</p> <p>Conclusion</p> <p>This case study shows that the combined efforts of local and international researchers can create a culture of evidence-based medicine within one country. It also shows that doing so required time and perseverance from international researchers combined with a readiness by local researchers to receive and actively promote the practice.</p

Selection of modalities, prescription, and technical issues in children on peritoneal dialysis

Peritoneal dialysis (PD) is widely employed as a dialytic therapy for uraemic children, especially in its automated form (APD), that is associated with less burden of care on patient and family than continuous ambulatory PD. Since APD offers a wide range of treatment options, based on intermittent and continuous regimens, prescription can be individualized according to patient’s age, body size, residual renal function, nutritional intake, and growth-related metabolic needs. Transport capacity of the peritoneal membrane of each individual patient should be assessed, and regularly monitored, by means of standardized peritoneal function tests validated in pediatric patients. To ensure maximum recruitment of peritoneal exchange area, fill volume should be scaled to body surface area and adapted to each patient, according to clinical tolerance and intraperitoneal pressure. PD solutions should be employed according to their biocompatibility and potential ultrafiltration capacity; new pH-neutral, glucose-free solutions can be used in an integrated way in separate dwells, or by appropriately mixing during the same dialytic session. Kinetic modelling software programs may help in the tailoring of PD prescription to individual patients’ characteristics and needs. Owing to advances in the technology of new APD machines, greater programming flexibility, memorized delivery control, and tele-dialysis are currently possible

A Century of Environmental Legislation

We find three intertwined ambitions that drove federal legislation over wildlife and biodiversity at the beginning of the 20th Century: establishment of multiple-use federal lands, the economic development of natural resources, and the maintenance of option values. We examine this federal intervention in natural resource use by analyzing roll-call votes over the past century. These votes involved decisions regarding public land that reallocated the returns to users by changing the asset's physical character or its usage rights. We suggest that long term consequences affecting current resource allocations arose from disparities between broadly dispersed benefits and locally concentrated socio-economic and geophysical (spatial) costs. We show that a primary intent of public land management has become to preserve multiple-use option values and identify important factors in computing those option values. We do this by demonstrating how the willingness to forego current benefits for future ones depends on the community's resource endowments. These endowments are defined not only in terms of users' current wealth accumulation but also from their expected ability to extract utility from natural resources over time