5,024 research outputs found
Associations between daily mortality in London and combined oxidant capacity, ozone and nitrogen dioxide.
Both nitrogen dioxide (NO2) and ozone (O3) are powerful oxidants in ambient air that are intimately linked through atmospheric chemistry and which continuously interchange over very short timescales. Based upon atmospheric chemistry alone, there is a strong, a priori, reason for considering O3 and NO2 together in epidemiological studies, rather than either of the two pollutants separately in single-pollutant models. This paper compares two approaches to this, using Ox, defined as O3 + NO2, as a single metric and also using O3 and NO2 together in two-pollutant models. We hypothesised that the magnitude of the association between Ox and daily mortality would be greater than for NO2 and O3 individually. Using collocated hourly measurements for O3 and NO2 in London, from 2000 to 2005, we carried out a time series analysis of daily mortality. We investigated O3, NO2 and Ox individually in single-pollutant Poisson regression models and NO2 and O3 jointly in two-pollutant models in both all-year and season-specific analyses. We observed larger associations for mean 24-h concentrations of Ox (1.30 % increase in mortality per 10 ppb) than for O3 (0.87 %) and NO2 (0 %) individually. However, when analysed jointly in two-pollutant models, associations for O3 (1.54 %) and NO2 (1.07 %) were comparable to the Ox association. Season-specific analyses broadly followed this pattern irrespective of whether the Ox concentrations were driven by O3 production (summer) or depletion (winter). This novel approach in air pollution epidemiology captures the simultaneous impact of both oxidants whilst avoiding many of the statistical issues associated with two-pollutant models and potentially simplifies health impact calculations
Egg shape changes at the theropod–bird transition, and a morphometric study of amniote eggs
The eggs of amniotes exhibit a remarkable variety of shapes,
from spherical to elongate and from symmetrical to asymmetrical.
We examine eggshell geometry in a diverse sample of fossil
and living amniotes using geometric morphometrics and linear
measurements. Our goal is to quantify patterns of morphospace
occupation and shape variation in the eggs of recent through to
Mesozoic birds (neornithe plus non-neornithe avialans), as well
as in eggs attributed to non-avialan theropods. In most amniotes,
eggs show significant deviation from sphericity, but departure
from symmetry around the equatorial axis is mostly confined
to theropods and birds. Mesozoic bird eggs differ significantly
from extant bird eggs, but extinct Cenozoic bird eggs do not. This
suggests that the range of egg shapes in extant birds had already
been attained in the Cenozoic. We conclude with a discussion
of possible biological factors imparting variation to egg shapes
during their formation in the oviduct
Goodpasture's Syndrome: Treatment With Nephrectomy and Renal Transplantation
Three young male patients developed acute glomerulonephritis and serious hemoptysis. All three had evidence of antiglomerular basement membrane (anti-GBM) antibodies in their serum and native kidneys. The pulmonary hemorrhages ceased after bilateral nephrectomy and splenectomy accompanied by irregular treatment with steroids and other immunosuppressants. Renal homotransplantation was successfully carried out from 95 to 162 days later, after circulating anti-GBM antibodies had disappeared. Two of the homografts were biopsied and the third was removed 20, 34, and 2 months posttransplantation, respectively, and contained little or no immunoglobulin. Therefore, Goodpasture's syndrome does not contraindicate renal transplantation under the stipulated conditions of staged therapy. © 1971, American Medical Association. All rights reserved
Introduction of a pyramid guiding process for general musculoskeletal physical rehabilitation
Successful instruction of a complicated subject as Physical Rehabilitation demands organization. To understand principles and processes of such a field demands a hierarchy of steps to achieve the intended outcome. This paper is intended to be an introduction to a proposed pyramid scheme of general physical rehabilitation principles. The purpose of the pyramid scheme is to allow for a greater understanding for the student and patient. As the respected Food Guide Pyramid accomplishes, the student will further appreciate and apply supported physical rehabilitation principles and the patient will understand that there is a progressive method to their functional healing process
Traffic pollution and the incidence of cardiorespiratory outcomes in an adult cohort in London.
OBJECTIVES: The epidemiological evidence for adverse health effects of long-term exposure to air and noise pollution from traffic is not coherent. Further, the relative roles of background versus near traffic pollution concentrations in this process are unclear. We investigated relationships between modelled concentrations of air and noise pollution from traffic and incident cardiorespiratory disease in London. METHODS: Among 211 016 adults aged 40-79 years registered in 75 Greater London practices between 2005 and 2011, the first diagnosis for a range of cardiovascular and respiratory outcomes were identified from primary care and hospital records. Annual baseline concentrations for nitrogen oxide (NOx), particulate matter with a median aerodynamic diameter <2.5 μm (PM2.5) attributable to exhaust and non-exhaust sources, traffic intensity and noise were estimated at 20 m(2) resolution from dispersion models, linked to clinical data via residential postcode. HRs were adjusted for confounders including smoking and area deprivation. RESULTS: The largest observed associations were between traffic-related air pollution and heart failure (HR=1.10 for 20 μg/m(3) change in NOx, 95% CI 1.01 to 1.21). However, no other outcomes were consistently associated with any of the pollution indicators, including noise. The greater variations in modelled air pollution from traffic between practices, versus within, hampered meaningful fine spatial scale analyses. CONCLUSIONS: The associations observed with heart failure may suggest exacerbatory effects rather than underlying chronic disease. However, the overall failure to observe wider associations with traffic pollution may reflect that exposure estimates based on residence inadequately represent the relevant pattern of personal exposure, and future studies must address this issue
Solar cycle variation in solar f-mode frequencies and radius
Using data from the Global Oscillation Network Group (GONG) covering the
period from 1995 to 1998, we study the change with solar activity in solar
f-mode frequencies. The results are compared with similar changes detected from
the Michelson Doppler Imager (MDI) data. We find variations in f-mode
frequencies which are correlated with solar activity indices. If these changes
are due to variation in solar radius then the implications are that the solar
radius decreases by about 5 km from minimum to maximum activity.Comment: To appear in Solar Physic
By hook or by crook? Morphometry, competition and cooperation in rodent sperm
Background
Sperm design varies enormously across species and sperm competition is thought to be a major factor influencing this variation. However, the functional significance of many sperm traits is still poorly understood. The sperm of most murid rodents are characterised by an apical hook of the sperm head that varies markedly in extent across species. In the European woodmouse Apodemus sylvaticus (Muridae), the highly reflected apical hook of sperm is used to form sperm groups, or “trains,” which exhibited increased swimming velocity and thrusting force compared to individual sperm.
Methodology/Principal Findings
Here we use a comparative study of murine rodent sperm and demonstrate that the apical hook and sperm cooperation are likely to be general adaptations to sperm competition in rodents. We found that species with relatively larger testes, and therefore more intense sperm competition, have a longer, more reflected apical sperm hook. In addition, we show that sperm groups also occur in rodents other than the European woodmouse.
Conclusions
Our results suggest that in rodents sperm cooperation is more widespread than assumed so far and highlight the importance of diploid versus haploid selection in the evolution of sperm design and function
Efficacy and Safety of iGlarLixi, Fixed-Ratio Combination of Insulin Glargine and Lixisenatide, Compared with Basal-Bolus Regimen in Patients with Type 2 Diabetes: Propensity Score Matched Analysis
INTRODUCTION:
Basal-bolus (BB) regimens are generally used to intensify basal insulin therapy in patients with type 2 diabetes (T2D) not meeting glycemic targets. However, drawbacks include multiple injection burden and risk of weight gain and hypoglycemia. A once-daily titratable fixed-ratio combination of insulin glargine 100 U/mL and lixisenatide (iGlarLixi) may provide a simple, well-tolerated, and efficacious alternative. We compared these treatments in a post hoc propensity score matched analysis using randomized trial data.
METHODS:
From the LixiLan-L study, 195 patients who had been randomized to iGlarLixi were matched for age, sex, race, T2D duration, baseline body mass index, glycated hemoglobin (HbA1c), fasting plasma glucose, insulin dose, and metformin use to 195 patients who had been randomized to a BB regimen in the GetGoal Duo-2 trial.
RESULTS:
At study end, estimated treatment differences for reduction in HbA1c and weight change, and ratio of hypoglycemia events per patient-year (BB vs iGlarLixi) were − 0.28% (standard error 0.08, P = 0.0002), − 1.32 kg (standard error 0.30, P < 0.0001), and 2.85 (P < 0.0001), respectively, all favoring iGlarLixi over BB. Also, proportions of patients reaching individual and composite goals (HbA1c < 7% [< 53 mmol/mol], no weight gain, and no hypoglycemia) were higher in the iGlarLixi compared with the BB treatment group. Gastrointestinal side effects were more common with iGlarLixi.
CONCLUSIONS:
In patients with T2D inadequately controlled on basal insulin, iGlarLixi offers an effective alternative to BB regimen for reducing HbA1c, without increased risk of hypoglycemia and weight gain.
TRIAL REGISTRATION:
ClinicalTrials.gov: NCT02058160 (LixiLan-L trial); NCT01768559 (GetGoal Duo-2 trial)
Extremely long quasiparticle spin lifetimes in superconducting aluminium using MgO tunnel spin injectors
There has been an intense search in recent years for long-lived
spin-polarized carriers for spintronic and quantum-computing devices. Here we
report that spin polarized quasi-particles in superconducting aluminum layers
have surprisingly long spin-lifetimes, nearly a million times longer than in
their normal state. The lifetime is determined from the suppression of the
aluminum's superconductivity resulting from the accumulation of spin polarized
carriers in the aluminum layer using tunnel spin injectors. A Hanle effect,
observed in the presence of small in-plane orthogonal fields, is shown to be
quantitatively consistent with the presence of long-lived spin polarized
quasi-particles. Our experiments show that the superconducting state can be
significantly modified by small electric currents, much smaller than the
critical current, which is potentially useful for devices involving
superconducting qubits
On Poincare and logarithmic Sobolev inequalities for a class of singular Gibbs measures
This note, mostly expository, is devoted to Poincar{\'e} and log-Sobolev
inequalities for a class of Boltzmann-Gibbs measures with singular interaction.
Such measures allow to model one-dimensional particles with confinement and
singular pair interaction. The functional inequalities come from convexity. We
prove and characterize optimality in the case of quadratic confinement via a
factorization of the measure. This optimality phenomenon holds for all beta
Hermite ensembles including the Gaussian unitary ensemble, a famous exactly
solvable model of random matrix theory. We further explore exact solvability by
reviewing the relation to Dyson-Ornstein-Uhlenbeck diffusion dynamics admitting
the Hermite-Lassalle orthogonal polynomials as a complete set of
eigenfunctions. We also discuss the consequence of the log-Sobolev inequality
in terms of concentration of measure for Lipschitz functions such as maxima and
linear statistics.Comment: Minor improvements. To appear in Geometric Aspects of Functional
Analysis -- Israel Seminar (GAFA) 2017-2019", Lecture Notes in Mathematics
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