Developing a preliminary recharge model of the Nile Basin to help interpret GRACE data

GRACE data provides a new and exciting opportunity to gain a direct and independent measure of water mass variation on a regional scale, but the data must be combined with hydrological modelling to indicate in which part of the water cycle the mass change has occurred. Processing GRACE data through a series of spectral filters indicates a seasonal variation to gravity mass (±0.005 mGal) thought to relate to the downstream movement of water in the catchment, and delayed storage from groundwater, following the wet season in the upper catchment. To help interpret these data a groundwater recharge model was developed for the Nile Catchment using the model ZOODRM (a distributed modelling code for calculating spatial and temporal variations in groundwater recharge). ZOODRM was an appropriate model to use for this work, due to the lower data demands of the model, relative to other groundwater models, the ability of the model to use entirely remotely-sensed input data, and the added functionality of runoff routing. Rainfall (NOAA data) and ET data were sourced from the FEWS NET African Data Dissemination Service. Geological data was sourced from the digital geology map of the world, landuse data from the USGS and the DEM data from ESRI. Initial model results indicate groundwater recharge across the basin of 0-4mma-1, with obvious considerable spatial variability. The results indicate the importance of groundwater in storing rainfall, and releasing it slowly throughout the year in different parts of the catchment. Only by modelling this process can GRACE data be reliably interpreted hydrologically. Despite only a qualitative interpretation of the GRACE data having been achieved within this preliminary study, the work has indicated that the ZOODRM model can be used with entirely remotely-sensed data, and that sufficient data exists for the Nile Basin to construct a plausible recharge model. Future work is now required to properly calibrate the model to enable closer comparison of the Nile GRACE data

Pulsating waves in nonlinear magnetoconvection

Numerical experiments on compressible magnetoconvection reveal a new type of periodic oscillation, associated with alternating streaming motion. Analogous behaviour in a Boussinesq fluid is constrained by extra symmetry. A low-order model confirms that these pulsating waves appear via a pitchfork-Hopf-gluing bifurcation sequence from the steady state

Bimodal granulocyte transit time through the human lung demonstrated by deconvolution analysis

AbstractThe lungs are an important site of granulocyte pooling. The aim of the study is to quantify pulmonary vascular granulocyte transit time using deconvolution analysis, as has previously been performed to measure pulmonary red cell transit time. Granulocyte and red cell studies were performed in separate groups of patients. Both cell types were labelled with Tc-99m, which for granulocyte labelling was complexed with hexamethylpropyleneamine oxime (HMPAO). The red cell impulse response function (IRF) was monoexponential with a median transit time of 4·3 s. The granulocyte IRF was biexponential in 19 of 22 subjects, 18 of whom had systemic inflammation (inflammatory bowel disease, systemic vasculitis or graft-vs-host disease) and four were controls without inflammatory disease. The median transit time of the fast component ranged from 20 to 25 s and of the slow component 120–138 s in the four patient groups. The fraction of cells undergoing slow transit correlated significantly with (a) mean granulocyte transit time and (b) the fraction showing shape change in vitro. We conclude that granulocyte transit time through the pulmonary circulation is bimodal and that shape-changed (activated) cells transit more slowly that non-activated cells. The size of the fraction undergoing slow transit is closely related to mean granulocyte transit time and is an important determinant of the size of the pulmonary vascular granulocyte pool

Trends in HIV testing and recording of HIV status in the UK primary care setting: a retrospective cohort study 1995-2005

Objectives: To provide nationally representative data on trends in HIV testing in primary care and to estimate the proportion of diagnosed HIV positive individuals known to general practitioners (GPs). Methods: We undertook a retrospective cohort study between 1995 and 2005 of all general practices contributing data to the UK General Practice Research Database (GPRD), and data on persons accessing HIV care (Survey of Prevalent HIV Infections Diagnosed). We identified all practice-registered patients where an HIV test or HIV positive status is recorded in their general practice records. HIV testing in primary care and prevalence of recorded HIV positive status in primary care were estimated. Results: Despite 11-fold increases in male testing and 19-fold increases in non-pregnant female testing between 1995 and 2005, HIV testing rates remained low in 2005 at 71.3 and 61.2 tests per 100 000 person years for males and females, respectively, peaking at 162.5 and 173.8 per 100 000 person years at 25–34 years of age. Inclusion of antenatal tests yielded a 129-fold increase in women over the 10-year period. In 2005, 50.7% of HIV positive individuals had their diagnosis recorded with a lower proportion in London (41.8%) than outside the capital (60.1%). Conclusion: HIV testing rates in primary care remain low. Normalisation of HIV testing and recording in primary care in antenatal testing has not been accompanied by a step change in wider HIV testing practice. Recording of HIV positive status by GPs remains low and GPs may be unaware of HIV-related morbidity or potential drug interactions

Trends in sexually transmitted infections in general practice 1990-2000: population based study using data from the UK general practice research database

Objective: To describe the contribution of primary care to the diagnosis and management of sexually transmitted infections in the United Kingdom, 1990-2000, in the context of increasing incidence of infections in genitourinary medicine clinics. Design: Population based study. Setting: UK primary care. Participants: Patients registered in the UK general practice research database. Main outcome measures: Incidence of diagnosed sexually transmitted infections in primary care and estimation of the proportion of major such infections diagnosed in primary care. Results: An estimated 23.0% of chlamydia cases in women but only 5.3% in men were diagnosed and treated in primary care during 1998-2000, along with 49.2% cases of non-specific urethritis and urethral discharge in men and 5.7% cases of gonorrhoea in women and 2.9% in men. Rates of diagnosis in primary care rose substantially in the late 1990s. Conclusions: A substantial and increasing number of sexually transmitted infections are diagnosed and treated in primary care in the United Kingdom, with sex ratios differing from those in genitourinary medicine clinics. Large numbers of men are treated in primary care for presumptive sexually transmitted infections

Groundwater, flooding and hydrological functioning in the Findhorn floodplain, Scotland

A large floodplain of the River Findhorn, northeast Scotland, was investigated using hydrogeological and hydrochemical methods (including residence time indicators) to characterise groundwater/surface-water coupling and groundwater flooding. The study demonstrated widespread stratification within the floodplain: shallow (30 mm). Persistent groundwater flooding occurs within topographical lows and also in the discharge zone where it is largely managed with a series of drains constructed in the 19th century. The significant and complex role of groundwater in floodplains, demonstrated by this study, highlights the importance of fully considering groundwater in flood management schemes

Towards a formalism for mapping the spacetimes of massive compact objects: Bumpy black holes and their orbits

Observations have established that extremely compact, massive objects are common in the universe. It is generally accepted that these objects are black holes. As observations improve, it becomes possible to test this hypothesis in ever greater detail. In particular, it is or will be possible to measure the properties of orbits deep in the strong field of a black hole candidate (using x-ray timing or with gravitational-waves) and to test whether they have the characteristics of black hole orbits in general relativity. Such measurements can be used to map the spacetime of a massive compact object, testing whether the object's multipoles satisfy the strict constraints of the black hole hypothesis. Such a test requires that we compare against objects with the ``wrong'' multipole structure. In this paper, we present tools for constructing bumpy black holes: objects that are almost black holes, but that have some multipoles with the wrong value. The spacetimes which we present are good deep into the strong field of the object -- we do not use a large r expansion, except to make contact with weak field intuition. Also, our spacetimes reduce to the black hole spacetimes of general relativity when the ``bumpiness'' is set to zero. We propose bumpy black holes as the foundation for a null experiment: if black hole candidates are the black holes of general relativity, their bumpiness should be zero. By comparing orbits in a bumpy spacetime with those of an astrophysical source, observations should be able to test this hypothesis, stringently testing whether they are the black holes of general relativity. (Abridged)Comment: 16 pages + 2 appendices + 3 figures. Submitted to PR

Correlates of physical activity in children and adolescents with intellectual disabilities: a systematic review

Background: Children and adolescents with intellectual disabilities (ID) participate in low levels of physical activity. To inform the development of interventions, we need to better understand factors associated with physical activity. The aim of this study was therefore to systematically review correlates of physical activity in children and adolescents with ID. Methods: The review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses guidelines. Ovid MEDLINE, Ovid Embase, Web of Science, ERIC, CINAHL and PsycINFO were searched between 1 January 1990 and 29 February 2020 to identify English‐language studies, which examined correlates of free‐living physical activity in children and adolescents (0–19 years) with ID. Study quality was assessed. Correlates were analysed using a narrative synthesis and classified using the socioecological model as intrapersonal, interpersonal, organisational or environmental. Results: Fifteen studies published between 2010 and 2019 met the inclusion criteria and were included in the review. Forty‐eight individual correlates were identified. Studies were predominantly focused on intrapersonal‐level correlates. Of those correlates investigated in more than one study (n = 6), having better motor development was positively associated with physical activity. Inconsistent results were found for age and cardiorespiratory fitness. Sex, percentage body fat and body mass index were not correlated. No interpersonal‐level, organisational‐level or environmental‐level correlates were included in more than one study. Conclusions: To date, we have limited and inconclusive evidence about correlates of physical activity in children and adolescents with ID. Only when future studies unravel correlates and determinants, across all domains of the socioecological model, will the potential opportunities to improve health by increasing physical activity levels be achievable

Abelian Magnetic Monopole Dominance in Quark Confinement

We prove Abelian magnetic monopole dominance in the string tension of QCD. Abelian and monopole dominance in low energy physics of QCD has been confirmed for various quantities by recent Monte Carlo simulations of lattice gauge theory. In order to prove this dominance, we use the reformulation of continuum Yang-Mills theory in the maximal Abelian gauge as a deformation of a topological field theory of magnetic monopoles, which was proposed in the previous article by the author. This reformulation provides an efficient way for incorporating the magnetic monopole configuration as a topological non-trivial configuration in the functional integral. We derive a version of the non-Abelian Stokes theorem and use it to estimate the expectation value of the Wilson loop. This clearly exhibits the role played by the magnetic monopole as an origin of the Berry phase in the calculation of the Wilson loop in the manifestly gauge invariant manner. We show that the string tension derived from the diagonal (abelian) Wilson loop in the topological field theory (studied in the previous article) converges to that of the full non-Abelian Wilson loop in the limit of large Wilson loop. Therefore, within the above reformulation of QCD, this result (together with the previous result) completes the proof of quark confinement in QCD based on the criterion of the area law of the full non-Abelian Wilson loop.Comment: 33 pages, Latex, no figures, version accepted for publication in Phys. Rev. D (additions of sec. 4.5 and references, and minor changes

Nitrate, but not silver, ions induce spectral changes in Escherichia coli cytochrome d

AbstractThe absorbance maximum (630 nm) of reduced cytochrome d in Escherichia coli membrane particles was diminished by 160 μM AgNO3 or NaNO3 and accompanied by the formation of a species with an absorption maximum at 640–645 nm. Nitrite, trioxodinitrate and nitric oxide elicited qualitatively similar, but faster, changes in the spectrum of cytochrome d, suggesting that formation of a nitrosyl complex may be involved in all cases. In direct contrast to an earlier report, silver ions (160 υM) were without effect on the α-bands of reduced cytochromes d, b or a1