Relative decompression risks of spacecraft cabin atmospheres

Relative decompression risk studies of spacecraft cabin atmosphere using miniature pig

Distilling Programs to Prove Termination

The problem of determining whether or not any program terminates was shown to be undecidable by Turing, but recent advances in the area have allowed this information to be determined for a large class of programs. The classic method for deciding whether a program terminates dates back to Turing himself and involves finding a ranking function that maps a program state to a well-order, and then proving that the result of this function decreases for every possible program transition. More recent approaches to proving termination have involved moving away from the search for a single ranking function and toward a search for a set of ranking functions; this set is a choice of ranking functions and a disjunctive termination argument is used. In this paper, we describe a new technique for determining whether programs terminate. Our technique is applied to the output of the distillation program transformation that converts programs into a simplified form called distilled form. Programs in distilled form are converted into a corresponding labelled transition system and termination can be demonstrated by showing that all possible infinite traces through this labelled transition system would result in an infinite descent of well-founded data values. We demonstrate our technique on a number of examples, and compare it to previous work.Comment: In Proceedings VPT/HCVS 2020, arXiv:2008.02483. This work owes a lot to the input of Neil Jones, who provided many useful insights and ideas on the subject matter presented her

Relative Decompression Risks of Spacecraft Cabin Atmospheres - Comparision of Gases Using Miniature Pigs Final Report

Using miniature pigs for analysis of altitude decompression sickness and relative decompression hazards of various cabin atmospheres of inert gase

The Generalized Ricci Flow for 3D Manifolds with One Killing Vector

We consider 3D flow equations inspired by the renormalization group (RG) equations of string theory with a three dimensional target space. By modifying the flow equations to include a U(1) gauge field, and adding carefully chosen De Turck terms, we are able to extend recent 2D results of Bakas to the case of a 3D Riemannian metric with one Killing vector. In particular, we show that the RG flow with De Turck terms can be reduced to two equations: the continual Toda flow solved by Bakas, plus its linearizaton. We find exact solutions which flow to homogeneous but not always isotropic geometries

Colorectal cancer

This is the final version of the article. Available from the publisher via the DOI in this record.This is one of a series of occasional articles highlighting conditions that may be more common than many doctors realise or may be missed at first presentation. Easily Missed serie

Prostate Cancer in Primary Care

This is the final version of the article. Available from Springer Verlag via the DOI in this record.Prostate cancer is a common malignancy seen worldwide. The incidence has risen in recent decades, mainly fuelled by more widespread use of prostate-specific antigen (PSA) testing, although prostate cancer mortality rates have remained relatively static over that time period. A man's risk of prostate cancer is affected by his age and family history of the disease. Men with prostate cancer generally present symptomatically in primary care settings, although some diagnoses are made in asymptomatic men undergoing opportunistic PSA screening. Symptoms traditionally thought to correlate with prostate cancer include lower urinary tract symptoms (LUTS), such as nocturia and poor urinary stream, erectile dysfunction and visible haematuria. However, there is significant crossover in symptoms between prostate cancer and benign conditions affecting the prostate such as benign prostatic hypertrophy (BPH) and prostatitis, making it very challenging to distinguish between them on the basis of symptoms. The evidence for the performance of PSA in asymptomatic and symptomatic men for the diagnosis of prostate cancer is equivocal. PSA is subject to false positive and false negative results, affecting its clinical utility as a standalone test. Clinicians need to counsel men about the risks and benefits of PSA testing to inform their decision-making. Digital rectal examination (DRE) by primary care clinicians has some evidence to show discrimination between benign and malignant conditions affecting the prostate. Patients referred to secondary care for diagnostic testing for prostate cancer will typically undergo a transrectal or transperineal biopsy, where a number of samples are taken and sent for histological examination. These biopsies are invasive procedures with side effects and a risk of infection and sepsis, and alternative tests such as multiparametric magnetic resonance imaging (mpMRI) are currently being trialled for their accuracy and safety in diagnosing clinically significant prostate cancer

The measurement of lubricant-film thickness using ultrasound

Ultrasound is reflected from a liquid layer between two solid bodies. This reflection depends on the ultrasonic frequency, the acoustic properties of the liquid and solid, and the layer thickness. If the wavelength is much greater than the liquid-layer thickness, then the response is governed by the stiffness of the layer. If the wavelength and layer thickness are similar, then the interaction of ultrasound with the layer is controlled by its resonant behaviour. This stiffness governed response and resonant response can be used to determine the thickness of the liquid layer, if the other parameters are known. In this paper, ultrasound has been developed as a method to determine the thickness of lubricating films in bearing systems. An ultrasonic transducer is positioned on the outside of a bearing shell such that the wave is focused on the lubricant-film layer. The transducer is used to both emit and receive wide-band ultrasonic pulses. For a particular lubricant film, the reflected pulse is processed to give a reflection-coefficient spectrum. The lubricant-film thickness is then obtained from either the layer stiffness or the resonant frequency. The method has been validated using fluid wedges at ambient pressure between flat and curved surfaces. Experiments on the elastohydrodynamic film formed between a sliding ball and a flat surface were performed. Film-thickness values in the range 50-500 nm were recorded, which agreed well with theoretical film-formation predictions. Similar measurements have been made on the oil film between the balls and outer raceway of a deep-groove ball bearing

Earth - venus trajectories, 1968-69, volume 4, part b

Earth-venus trajectories 1968-196