Observation of HCN hyperfine line anomalies towards low- and high-mass star-forming cores

HCN is becoming a popular choice of molecule for studying star formation in both low- and high-mass regions and for other astrophysical sources from comets to high-redshift galaxies. However, a major and often overlooked difficulty with HCN is that it can exhibit non-local thermodynamic equilibrium (non-LTE) behaviour in its hyperfine line structure. Individual hyperfine lines can be strongly boosted or suppressed. In low-mass star-forming cloud observations, this could possibly lead to large errors in the calculation of opacity and excitation temperature, while in massive star-forming clouds, where the hyperfine lines are blended due to turbulent broadening, errors will arise in infall measurements that are based on the separation of the peaks in a self-absorbed profile. The underlying line shape cannot be known for certain if hyperfine anomalies are present. We present a first observational investigation of these anomalies across a range of conditions and transitions by carrying out a survey of low-mass starless cores (in Taurus & Ophiuchus) and high-mass protostellar objects (in the G333 giant molecular cloud) using hydrogen cyanide (HCN) J=1-0 and J=3-2 emission lines. We quantify the degree of anomaly in these two rotational levels by considering ratios of individual hyperfine lines compared to LTE values. We find that all the cores observed show some degree of anomaly while many of the lines are severely anomalous. We conclude that HCN hyperfine anomalies are common in both lines in both low-mass and high-mass protostellar objects, and we discuss the differing hypotheses for the generation of the anomalies. In light of the results, we favour a line overlap effect for the origins of the anomalies. We discuss the implications for the use of HCN as a dynamical tracer and suggest in particular that the J=1-0, F=0-1 hyperfine line should be avoided in quantitative calculations.Comment: 17 pages, 8 figure

Non-Perturbative Tachyon Potential from the Wilsonian Renormalization Group

The derivative expansion of the Wilsonian renormalization group generates additional terms in the effective beta-functions not present in the perturbative approach. Applied to the nonlinear sigma model, to lowest order the vanishing of the beta-function for the tachyon field generates an equation analogous to that found in open string field theory. Although the nonlinear term depends on the cut-off function, this arbitrariness can be removed by a rescaling of the tachyon field.Comment: 6 pages, further references adde

User Studies for Digital Library Development

As the information environment becomes increasingly electronic, digital libraries have proliferated, but the focus has often been on innovations in technology and not the user. Research and analysis of users is essential to fine-tune the content and approach of digital libraries to the diverging requirements and expectations of incredibly varied communities and to ensure libraries are effective, accessible and sustainable in the long term. This book provides a clear overview of the user studies domain and user issues in digital libraries

Carriage of Staphylococcus aureus in the elderly

The point prevalence and incidence of Staphylococcus aureus (methicillin-sensitive and -resistant) carriage by inpatients on acute elderly care wards was estimated. The relationship to body site and to previous admissions to hospital or other institutions was determined. Fifty-five patients were included in the point prevalence study and 136 in the incidence study, which was performed over a two-month period. One in three patients carried S. aureus and 1 in 20 was infected. The incidence rate for MRSA was 2.9%. No endemic strain was found. Nostrils were significantly associated with carriage, and skin break isolates were significant in the point prevalence survey. Screening these sites alone would be most cost effective

Bayesian analysis of the low-resolution polarized 3-year WMAP sky maps

We apply a previously developed Gibbs sampling framework to the foreground corrected 3-yr WMAP polarization data and compute the power spectrum and residual foreground template amplitude posterior distributions. We first analyze the co-added Q- and V-band data, and compare our results to the likelihood code published by the WMAP team. We find good agreement, and thus verify the numerics and data processing steps of both approaches. However, we also analyze the Q- and V-bands separately, allowing for non-zero EB cross-correlations and including two individual foreground template amplitudes tracing synchrotron and dust emission. In these analyses, we find tentative evidence of systematics: The foreground tracers correlate with each of the Q- and V-band sky maps individually, although not with the co-added QV map; there is a noticeable negative EB cross-correlation at l <~ 16 in the V-band map; and finally, when relaxing the constraints on EB and BB, noticeable differences are observed between the marginalized band powers in the Q- and V-bands. Further studies of these features are imperative, given the importance of the low-l EE spectrum on the optical depth of reionization tau and the spectral index of scalar perturbations n_s.Comment: 5 pages, 4 figures, submitted to ApJ

Lineshape of the thermopower of quantum dots

Quantum dots are an important model system for thermoelectric phenomena, and may be used to enhance the thermal-to-electric energy conversion efficiency in functional materials. It is therefore important to obtain a detailed understanding of a quantum-dot's thermopower as a function of the Fermi energy. However, so far it has proven difficult to take effects of co-tunnelling into account in the interpretation of experimental data. Here we show that a single-electron tunnelling model, using knowledge of the dot's electrical conductance which in fact includes all-order co-tunneling effects, predicts the thermopower of quantum dots as a function of the relevant energy scales, in very good agreement with experiment.Comment: 10 pages, 5 figure

Dysphonia and dysphagia consequences of paediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS)

IMPORTANCE: Paediatric inflammatory multisystem syndrome, temporally associated with SARS-CoV-2 (PIMS-TS) is a novel disease first identified in 2020. Recent cohort studies have described the complex presentation and symptomatology. This paper provides detailed description of the dysphagia and dysphonia symptoms, management, and outcome. OBJECTIVE: To describe dysphagia and dysphonia in PIMS-TS. DESIGN: Retrospective cohort study. SETTING: Single tertiary and quaternary children's hospital. PARTICIPANTS: All 50 children treated for paediatric multisystem inflammatory disease between April and June 2020 were included in this study. MAIN OUTCOME(S) AND MEASURE(S): Dysphonia: GRBAS Perceptual Severity Scores, Vocal Handicap Index scores and the Vocal Tract Discomfort Scale. Dysphagia: Functional Oral Intake Scale. RESULTS: Fifty children met the diagnostic criteria for PIMS-TS. 33 (66%) were male. Median age was 10 years (range: 1–17). 36 (72%) were of Black, Asian or minority ethnic background. Nine (18%) required specialist assessment and management of dysphagia and/or dysphonia. Five (55%) were male with a median age of 9 years 7 months (range: 1–15 years). Symptoms typically resolved within three months. Two children presented with persisting dysphonia three months post-presentation. Neurological, inflammatory, and iatrogenic causes of dysphagia and dysphonia were identified. CONCLUSIONS AND RELEVANCE: Dysphonia and dysphagia are present in children with PIMS-TS. Further data is required to understand pathophysiology, estimate incidence, and determine prognostic factors. This preliminary data highlights the need for dysphagia and dysphonia screening and timely referral for specialist, multidisciplinary assessment and treatment to ensure short-term aspiration risk is managed and long-term, functional outcomes are optimised

Experimental Campaign on the Use of the Flat Jack Test in Cob Walls

The flat jack test is one of the most used investigation techniques in the area of architectural heritage conservation. Unfortunately, there are no results available in the literature reporting the use of the flat jack technique in cob walls. This paper presents the firs experimental campaign performed to validate the use of this Minor Destructive Technique (MDT) to determine the levels of stress in cob walls and their mechanical properties. Furthermore, three workshops organized and facilitated with the aim of increasing public engagement and awareness towards the conservation of earthen vernacular architecture are also presented

Bayesian Power Spectrum Analysis of the First-Year WMAP data

We present the first results from a Bayesian analysis of the WMAP first year data using a Gibbs sampling technique. Using two independent, parallel supercomputer codes we analyze the WMAP Q, V and W bands. The analysis results in a full probabilistic description of the information the WMAP data set contains about the power spectrum and the all-sky map of the cosmic microwave background anisotropies. We present the complete probability distributions for each C_l including any non-Gaussianities of the power spectrum likelihood. While we find good overall agreement with the previously published WMAP spectrum, our analysis uncovers discrepancies in the power spectrum estimates at low l multipoles. For example we claim the best-fit Lambda-CDM model is consistent with the C_2 inferred from our combined Q+V+W analysis with a 10% probability of an even larger theoretical C_2. Based on our exact analysis we can therefore attribute the "low quadrupole issue" to a statistical fluctuation.Comment: 5 pages. 4 figures. For additional information and data see http://www.astro.uiuc.edu/~iodwyer/research#wma

Zone-plate focusing of Bose-Einstein condensates for atom optics and erasable high-speed lithography of quantum electronic components

We show that Fresnel zone plates, fabricated in a solid surface, can sharply focus atomic Bose-Einstein condensates that quantum reflect from the surface or pass through the etched holes. The focusing process compresses the condensate by orders of magnitude despite inter-atomic repulsion. Crucially, the focusing dynamics are insensitive to quantum fluctuations of the atom cloud and largely preserve the condensates' coherence, suggesting applications in passive atom-optical elements, for example zone plate lenses that focus atomic matter waves and light at the same point to strengthen their interaction. We explore transmission zone-plate focusing of alkali atoms as a route to erasable and scalable lithography of quantum electronic components in two-dimensional electron gases embedded in semiconductor nanostructures. To do this, we calculate the density profile of a two-dimensional electron gas immediately below a patch of alkali atoms deposited on the surface of the nanostructure by zone-plate focusing. Our results reveal that surface-induced polarization of only a few thousand adsorbed atoms can locally deplete the electron gas. We show that, as a result, the focused deposition of alkali atoms by existing zone plates can create quantum electronic components on the 50 nm scale, comparable to that attainable by ion beam implantation but with minimal damage to either the nanostructure or electron gas.Comment: 13 pages, 7 figure