Dynamics of airflow in a short inhalation

During a rapid inhalation, such as a sniff, the flow in the airways accelerates and decays quickly. The consequences for flow development and convective trans- port of an inhaled gas were investigated in a subject geometry extending from the nose to the bronchi. The progress of flow transition and the advance of an inhaled non-absorbed gas were determined using highly resolved simulations of a sniff 0.5 s long, 1 litre per second peak flow, 364 ml inhaled volume. In the nose, the distribution of airflow evolved through three phases: (i) an initial transient of about 50 ms, roughly the filling time for a nasal volume, (ii) quasi-equilibrium over the majority of the inhalation, and (iii) a terminating phase. Flow transition commenced in the supraglottic region within 20ms, resulting in large- amplitude fluctuations persisting throughout the inhalation; in the nose, fluctuations that arose nearer peak flow were of much reduced intensity and diminished in the flow decay phase. Measures of gas concentration showed non-uniform build-up and wash-out of the inhaled gas in the nose. At the carina, the form of the temporal concentration profile reflected both shear dispersion and airway filling defects owing to recirculation regions.Comment: 15 page

The Eye in the Neck: Removal of a Sewing Needle from the Posterior Pharyngeal Wall

Foreign body ingestion is a frequent presenting complaint to most emergency departments but the finding of a sewing needle in the posterior pharynx particularly is a rare finding. We report a case of a male patient with a sewing needle lodged in the posterior pharynx despite a history suggestive of chicken bone ingestion, absent clinical features, and negative flexible endoscopic examination. The needle was only identified through cervical spine radiographs. Even subsequent pharyngoscopy, laryngoscopy, and upper oesophagoscopy all proved to be unremarkable with the patient eventually requiring a left neck exploration to remove the needle. The case outlines the importance of simple radiography in suspected foreign body ingestion, even though clinical and endoscopic findings may be unremarkable

Conditions for Generating Scale-Invariant Density Perturbations

We analyze the general conditions on the equation of state $w$ required for quantum fluctuations of a scalar field to produce a scale-invariant spectrum of density perturbations, including models which (in the four dimensional effective description) bounce from a contracting to an expanding phase. We show that there are only two robust cases: $w\approx -1$ (inflation) and $w \gg 1$ (the ekpyrotic/cyclic scenario). All other cases, including the $w \approx 0$ case considered by some authors, require extreme fine-tuning of initial conditions and/or the effective potential. For the ekpyrotic/cyclic ($w \gg 1$) case, we also analyze the small deviations from scale invariance.Comment: 6 pages, no figure

Content validity of the EORTC quality of life questionnaire QLQ-C30 for use in cancer

Aim The European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (QLQ-C30) is among the most widely used patient-reported outcome measures in cancer research and practice. It was developed prior to guidance that content should be established directly from patients to confirm it measures concepts of interest and is appropriate and comprehensive for the intended population. This study evaluated the content validity of the QLQ-C30 for use with cancer patients. Methods Adults undergoing cancer treatment in Europe and the USA participated in open-ended concept elicitation interviews regarding their functional health, symptoms, side-effects and impacts on health-related quality of life. Thematic analysis was conducted, and similarities across cancer types, disease stages and countries or languages were explored. Results Interviews with 113 patients with cancer (85 European, 28 USA) including breast, lung, prostate, colorectal and other cancers were conducted between 2016 and 2020. Conceptual saturation was achieved. The most frequently reported concepts were included in the QLQ-C30 conceptual framework. QLQ-C30 items were widely understood across language versions and were relevant to patients across cancer types and disease stages. While several new concepts were elicited such as difficulty climbing steps or stairs, weight loss, skin problems and numbness, many were not widely experienced and/or could be considered sub-concepts of existing concepts. Conclusions The QLQ-C30 demonstrates good evidence of content validity for the assessment of functional health, symptom burden and health-related quality of life in patients with localised-to-advanced cancer

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Constraints on the cosmic expansion history from GWTC-3

We use 47 gravitational-wave sources from the Third LIGO-Virgo-KAGRA Gravitational-Wave Transient Catalog (GWTC-3) to estimate the Hubble parameter $H(z)$, including its current value, the Hubble constant $H_0$. Each gravitational-wave (GW) signal provides the luminosity distance to the source and we estimate the corresponding redshift using two methods: the redshifted masses and a galaxy catalog. Using the binary black hole (BBH) redshifted masses, we simultaneously infer the source mass distribution and $H(z)$. The source mass distribution displays a peak around $34\, {\rm M_\odot}$, followed by a drop-off. Assuming this mass scale does not evolve with redshift results in a $H(z)$ measurement, yielding $H_0=68^{+12}_{-7} {\rm km\,s^{-1}\,Mpc^{-1}}$ ($68\%$ credible interval) when combined with the $H_0$ measurement from GW170817 and its electromagnetic counterpart. This represents an improvement of 17% with respect to the $H_0$ estimate from GWTC-1. The second method associates each GW event with its probable host galaxy in the catalog GLADE+, statistically marginalizing over the redshifts of each event's potential hosts. Assuming a fixed BBH population, we estimate a value of $H_0=68^{+8}_{-6} {\rm km\,s^{-1}\,Mpc^{-1}}$ with the galaxy catalog method, an improvement of 42% with respect to our GWTC-1 result and 20% with respect to recent $H_0$ studies using GWTC-2 events. However, we show that this result is strongly impacted by assumptions about the BBH source mass distribution; the only event which is not strongly impacted by such assumptions (and is thus informative about $H_0$) is the well-localized event GW190814