106 research outputs found
Influence of Weight Reduction on Blood Pressure; A Meta-analysis of Randomized Controlled Trials
Increased body weight is a strong risk factor for hypertension. A meta-analysis of randomized controlled trials was performed to estimate the effect of weight reduction on blood pressure overall and in population subgroups. Twenty-five randomized, controlled trials (comprising 34 strata) published between 1966 and 2002 with a total of 4874 participants were included. A random-effects model was used to account for heterogeneity among trials. A net weight reduction of -5.1 kg (95% confidence interval [CI], -6.03 to -4.25) by means of energy restriction, increased physical activity, or both reduced systolic blood pressure by -4.44 mm Hg (95% CI, -5.93 to -2.95) and diastolic blood pressure by -3.57 mm Hg (95% CI, -4.88 to -2.25). Blood pressure reductions were -1.05 mm Hg (95% CI, -1.43 to -0.66) systolic and -0.92 mm Hg (95% CI, -1.28 to -0.55) diastolic when expressed per kilogram of weight loss. As expected, significantly larger blood pressure reductions were observed in populations with an average weight loss >5 kg than in populations with less weight loss, both for systolic (-6.63 mm Hg [95% CI, -8.43 to -4.82] vs -2.70 mm Hg [ 95% CI, -4.59 to -0.81]) and diastolic (-5.12 mm Hg [95% CI, -6.48 to -3.75] vs -2.01 mm Hg [95% CI, -3.47 to -0.54]) blood pressure. The effect on diastolic blood pressure was significantly larger in populations taking antihypertensive drugs than in untreated populations (-5.31 mm Hg [95% CI, -6.64 to -3.99] vs -2.91 mm Hg [95% CI, -3.66 to -2.16]). This meta-analysis clearly shows that weight loss is important for the prevention and treatment of hypertension
Producing the event ready two photon polarization EPR state with linear optics devices
We propose a scheme to produce the maximally two photon polarization
entangled state(EPR state) with single photon sources and the linear optics
devices. In particular, our scheme requires the photon detectors only to
distinguish the vacuum and non-vacuum Fock number states. A sophisticated
photon detector distinguishing one or two photon states is unnecessary.Comment: Published in Phys. Rev. A alread
Field Measurements of Terrestrial and Martian Dust Devils
Surface-based measurements of terrestrial and martian dust devils/convective vortices provided from mobile and stationary platforms are discussed. Imaging of terrestrial dust devils has quantified their rotational and vertical wind speeds, translation speeds, dimensions, dust load, and frequency of occurrence. Imaging of martian dust devils has provided translation speeds and constraints on dimensions, but only limited constraints on vertical motion within a vortex. The longer mission durations on Mars afforded by long operating robotic landers and rovers have provided statistical quantification of vortex occurrence (time-of-sol, and recently seasonal) that has until recently not been a primary outcome of more temporally limited terrestrial dust devil measurement campaigns. Terrestrial measurement campaigns have included a more extensive range of measured vortex parameters (pressure, wind, morphology, etc.) than have martian opportunities, with electric field and direct measure of dust abundance not yet obtained on Mars. No martian robotic mission has yet provided contemporaneous high frequency wind and pressure measurements. Comparison of measured terrestrial and martian dust devil characteristics suggests that martian dust devils are larger and possess faster maximum rotational wind speeds, that the absolute magnitude of the pressure deficit within a terrestrial dust devil is an order of magnitude greater than a martian dust devil, and that the time-of-day variation in vortex frequency is similar. Recent terrestrial investigations have demonstrated the presence of diagnostic dust devil signals within seismic and infrasound measurements; an upcoming Mars robotic mission will obtain similar measurement types
Dust Devil Tracks
Dust devils that leave dark- or light-toned tracks are common on Mars and they can also be found on the Earthâs surface. Dust devil tracks (hereinafter DDTs) are ephemeral surface features with mostly sub-annual lifetimes. Regarding their size, DDT widths can range between âŒ1 m and âŒ1 km, depending on the diameter of dust devil that created the track, and DDT lengths range from a few tens of meters to several kilometers, limited by the duration and horizontal ground speed of dust devils. DDTs can be classified into three main types based on their morphology and albedo in contrast to their surroundings; all are found on both planets: (a) dark continuous DDTs, (b) dark cycloidal DDTs, and (c) bright DDTs. Dark continuous DDTs are the most common type on Mars. They are characterized by their relatively homogenous and continuous low albedo surface tracks. Based on terrestrial and martian in situ studies, these DDTs most likely form when surficial dust layers are removed to expose larger-grained substrate material (coarse sands of â„500 ÎŒm in diameter). The exposure of larger-grained materials changes the photometric properties of the surface; hence leading to lower albedo tracks because grain size is photometrically inversely proportional to the surface reflectance. However, although not observed so far, compositional differences (i.e., color differences) might also lead to albedo contrasts when dust is removed to expose substrate materials with mineralogical differences. For dark continuous DDTs, albedo drop measurements are around 2.5 % in the wavelength range of 550â850 nm on Mars and around 0.5 % in the wavelength range from 300â1100 nm on Earth. The removal of an equivalent layer thickness around 1 ÎŒm is sufficient for the formation of visible dark continuous DDTs on Mars and Earth. The next type of DDTs, dark cycloidal DDTs, are characterized by their low albedo pattern of overlapping scallops. Terrestrial in situ studies imply that they are formed when sand-sized material that is eroded from the outer vortex area of a dust devil is redeposited in annular patterns in the central vortex region. This type of DDT can also be found in on Mars in orbital image data, and although in situ studies are lacking, terrestrial analog studies, laboratory work, and numerical modeling suggest they have the same formation mechanism as those on Earth. Finally, bright DDTs are characterized by their continuous track pattern and high albedo compared to their undisturbed surroundings. They are found on both planets, but to date they have only been analyzed in situ on Earth. Here, the destruction of aggregates of dust, silt and sand by dust devils leads to smooth surfaces in contrast to the undisturbed rough surfaces surrounding the track. The resulting change in photometric properties occurs because the smoother surfaces have a higher reflectance compared to the surrounding rough surface, leading to bright DDTs. On Mars, the destruction of surficial dust-aggregates may also lead to bright DDTs. However, higher reflective surfaces may be produced by other formation mechanisms, such as dust compaction by passing dust devils, as this may also cause changes in photometric properties. On Mars, DDTs in general are found at all elevations and on a global scale, except on the permanent polar caps. DDT maximum areal densities occur during spring and summer in both hemispheres produced by an increase in dust devil activity caused by maximum insolation. Regionally, dust devil densities vary spatially likely controlled by changes in dust cover thicknesses and substrate materials. This variability makes it difficult to infer dust devil activity from DDT frequencies. Furthermore, only a fraction of dust devils leave tracks. However, DDTs can be used as proxies for dust devil lifetimes and wind directions and speeds, and they can also be used to predict lander or rover solar panel clearing events. Overall, the high DDT frequency in many areas on Mars leads to drastic albedo changes that affect large-scale weather patterns
Titan's Prolific Propane: The Cassini CIRS Perspective
In this paper we select large spectral averages of data from the Cassini
Composite Infrared Spectrometer (CIRS) obtained in limb-viewing mode at low
latitudes (30S--30N), greatly increasing the path length and hence
signal-to-noise ratio for optically thin trace species such as propane. By
modeling and subtracting the emissions of other gas species, we demonstrate
that at least six infrared bands of propane are detected by CIRS, including two
not previously identified in Titan spectra. Using a new line list for the range
1300-1400cm -1, along with an existing GEISA list, we retrieve propane
abundances from two bands at 748 and 1376 cm-1. At 748 cm-1 we retrieve 4.2 +/-
0.5 x 10(-7) (1-sigma error) at 2 mbar, in good agreement with previous
studies, although lack of hotbands in the present spectral atlas remains a
problem. We also determine 5.7 +/- 0.8 x 10(-7) at 2 mbar from the 1376 cm-1
band - a value that is probably affected by systematic errors including
continuum gradients due to haze and also an imperfect model of the n6 band of
ethane. This study clearly shows for the first time the ubiquity of propane's
emission bands across the thermal infrared spectrum of Titan, and points to an
urgent need for further laboratory spectroscopy work, both to provide the line
positions and intensities needed to model these bands, and also to further
characterize haze spectral opacity. The present lack of accurate modeling
capability for propane is an impediment not only for the measurement of propane
itself, but also for the search for the emissions of new molecules in many
spectral regions.Comment: 7 Figures, 3 Tables. Typeset in Latex with elsart.cls. In press for
Planetary and Space Scienc
Decreased expression of ABAT and STC2 hallmarks ER-positive inflammatory breast cancer and endocrine therapy resistance in advanced disease
Background: Patients with Estrogen Receptor α-positive (ER+) Inflammatory Breast Cancer (IBC) are less responsive to endocrine therapy compared with ER+ non-IBC (nIBC) patients. The study of ER+ IBC samples might reveal biomarkers for endocrine resistant breast cancer. Materials & methods: Gene expression profiles of ER+ samples from 201 patients were explored for genes that discriminated between IBC and nIBC. Classifier genes were applied onto clinically annotated expression data from 947 patients with ER+ breast cancer and validated with RT-qPCR for 231 patients treated with first-line tamoxifen. Relationships with metastasis-free survival (MFS) and progression-free survival (PFS) following adjuvant and first-line endocrine treatment, respectively, were investigated using Cox regression analysis. Results: A metagene of six genes including the genes encoding for 4-aminobutyrate aminotransferase (ABAT) and Stanniocalcin-2 (STC2) were identified to distinguish 22 ER+ IBC from 43 ER+ nIBC patients and remained discriminatory in an independent series of 136 patients. The metagene and two genes were not prognostic in 517 (neo)adjuvant untreated lymph node-negative ER+ nIBC breast cancer patients. Only ABAT was related to outcome in 250 patients treated with adjuvant tamoxifen. Three independent series of in total 411 patients with advanced disease showed increased metagene scores and decreased expression of ABAT and STC2 to be correlated with poor first-line endocrine therapy outcome. The biomarkers remained predictive for first-line tamoxifen treatment outcome in multivariate analysis including traditional factors or published signatures. In an exploratory analysis, ABAT and STC2 protein expression levels had no relation with PFS after first-line tamoxifen. Conclusions: This study utilized ER+ IBC to identify a metagene including ABAT and STC2 as predictive biomarkers for endocrine therapy resistance
Circulating B-vitamin biomarkers and B-vitamin supplement use in relation to quality of life in patients with colorectal cancer: results from the FOCUS consortium
Background: B vitamins have been associated with the risk and progression of colorectal cancer (CRC), given their central roles in nucleotide synthesis and methylation, yet their association with quality of life in established CRC is unclear.Objectives: To investigate whether quality of life 6 months postdiagnosis is associated with: 1) circulating concentrations of B vitamins and related biomarkers 6 months postdiagnosis; 2) changes in these concentrations between diagnosis and 6 months postdiagnosis; 3) B-vitamin supplement use 6 months postdiagnosis; and 4) changes in B-vitamin supplement use between diagnosis and 6 months postdiagnosis.Methods: We included 1676 newly diagnosed stage I-III CRC patients from 3 prospective European cohorts. Circulating concentrations of 9 biomarkers related to the B vitamins folate, riboflavin, vitamin B6, and cobalamin were measured at diagnosis and 6 months postdiagnosis. Information on dietary supplement use was collected at both time points. Health-related quality of life (global quality of life, functioning scales, and fatigue) was assessed by the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire 6 months postdiagnosis. Confounder-adjusted linear regression analyses were performed, adjusted for multiple testing.Results: Higher pyridoxal 5'-phosphate (PLP) was cross-sectionally associated with better physical, role, and social functioning, as well as reduced fatigue, 6 months postdiagnosis. Associations were observed for a doubling in the hydroxykynurenine ratio [3-hydroxykynurenine: (kynurenic acid + xanthurenic acid + 3-hydroxyanthranilic acid + anthranilic acid); an inverse marker of vitamin B6] and both reduced global quality of life (beta = -3.62; 95% CI: -5.88, -1.36) and worse physical functioning (beta = -5.01; 95% CI: -7.09, -2.94). Dose-response relations were observed for PLP and quality of life. No associations were observed for changes in biomarker concentrations between diagnosis and 6 months. Participants who stopped using B-vitamin supplements after diagnosis reported higher fatigue than nonusers.Conclusions: Higher vitamin B6 status was associated with better quality of life, yet limited associations were observed for the use of B-vitamin supplements. Vitamin B6 needs further study to clarify its role in relation to quality of life
Orbital Observations of Dust Lofted by Daytime Convective Turbulence
Over the past several decades, orbital observations of lofted dust have revealed the importance of mineral aerosols as a climate forcing mechanism on both Earth and Mars. Increasingly detailed and diverse data sets have provided an ever-improving understanding of dust sources, transport pathways, and sinks on both planets, but the role of dust in modulating atmospheric processes is complex and not always well understood. We present a review of orbital observations of entrained dust on Earth and Mars, particularly that produced by the dust-laden structures produced by daytime convective turbulence called âdust devilsâ. On Earth, dust devils are thought to contribute only a small fraction of the atmospheric dust budget; accordingly, there are not yet any published accounts of their occurrence from orbit. In contrast, dust devils on Mars are thought to account for several tens of percent of the planetâs atmospheric dust budget; the literature regarding martian dust devils is quite rich. Because terrestrial dust devils may temporarily contribute significantly to local dust loading and lowered air quality, we suggest that martian dust devil studies may inform future studies of convectively-lofted dust on Earth
A Pre-Landing Assessment of Regolith Properties at the InSight Landing Site
This article discusses relevant physical properties of the regolith at the Mars InSight landing site as understood prior to landing of the spacecraft. InSight will land in the northern lowland plains of Mars, close to the equator, where the regolith is estimated to be â„3--5 m thick. These investigations of physical properties have relied on data collected from Mars orbital measurements, previously collected lander and rover data, results of studies of data and samples from Apollo lunar missions, laboratory measurements on regolith simulants, and theoretical studies. The investigations include changes in properties with depth and temperature. Mechanical properties investigated include density, grain-size distribution, cohesion, and angle of internal friction. Thermophysical properties include thermal inertia, surface emissivity and albedo, thermal conductivity and diffusivity, and specific heat. Regolith elastic properties not only include parameters that control seismic wave velocities in the immediate vicinity of the Insight lander but also coupling of the lander and other potential noise sources to the InSight broadband seismometer. The related properties include Poissonâs ratio, P- and S-wave velocities, Youngâs modulus, and seismic attenuation. Finally, mass diffusivity was investigated to estimate gas movements in the regolith driven by atmospheric pressure changes. Physical properties presented here are all to some degree speculative. However, they form a basis for interpretation of the early data to be returned from the InSight mission.Additional co-authors: Nick Teanby and Sharon Keda
Impact of dietary and lifestyle factors on the prevalence of hypertension in Western populations
Data on the impact of the many dietary and lifestyle factors on the prevalence of hypertension in Western societies are lacking. This study quantified the contributions of body weight, physical inactivity and dietary factors to the prevalence of hypertension in Finland, Italy, the Netherlands, United Kingdom (UK) and USA. METHODS: Distributions of blood pressure (BP) and risk factors in Western populations were obtained from nationwide surveys. The effect of risk factors on BP was assessed by meta-regression analysis of randomized trials, published between 1966 and March 2001. Population attributable risk percentages (PAR%) for hypertension (i.e. systolic BP > or =140 mmHg) were computed for all risk factors in the five countries. RESULTS: Being overweight made the largest contribution to hypertension, with PAR% between 11% (Italy) and 25% (USA). PAR% were 5-13% for physical inactivity, 9-17% for high sodium intake, 4-17% for low potassium intake and 4-8% for low magnesium intake. The impact of alcohol was small (2-3%) in all populations. PAR% varied among populations for inadequate intake of calcium (2-8%), magnesium (4-8%), coffee (0-9%) and fish fatty acids (3-16%). CONCLUSIONS: Diet and lifestyle have a substantial impact on hypertension in Western societies, with being overweight, physical inactivity, high sodium intake and low potassium intake being the main contributors. The relative significance of different risk factors varies among populations, which is important for preventative strategies
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