35 research outputs found

    Global analysis of electromagnetic moments in odd near doubly magic nuclei

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    We use the nuclear DFT approach to determine nuclear electric quadrupole and magnetic dipole moments in all one-particle and one-hole neighbors of eight doubly magic nuclei. We align angular momenta along the intrinsic axial-symmetry axis with broken time-reversal symmetry, which allows us to explore fully the self-consistent charge, spin, and current polarizations. Spectroscopic moments are determined for symmetry-restored wave functions and compared with available experimental data. We find that the obtained polarizations do not call for using quadrupole- or dipole-moment operators with effective charges or effective g-factors.Comment: 15 LaTeX pages, 9 figure

    Exercise training reduces the acute physiological severity of post-menopausal hot flushes.

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    A hot-flush is characterised by feelings of intense heat, profuse elevations in cutaneous vasodilation and sweating, and reduced brain blood flow. Exercise training reduces self-reported hot-flush severity, but underpinning physiological data are lacking. We hypothesised that exercise training attenuates the changes in cutaneous vasodilation, sweat rate and cerebral blood flow during a hot flush. In a preference trial, 18 symptomatic post-menopausal women underwent a passive heat stress to induce hot-flushes at baseline and follow-up. Fourteen participants opted for a 16-week moderate intensity supervised exercise intervention, while 7 participants opted for control. Sweat rate, cutaneous vasodilation, blood pressure, heart rate and middle cerebral artery velocity (MCAv) were measured during the hot-flushes. Data were binned into eight equal segments, each representing 12.5% of hot flush duration. Weekly self-reported frequency and severity of hot flushes were also recorded at baseline and follow-up. Following training, mean hot-flush sweat rate decreased by 0.04 mg·cm2 ·min-1 at the chest (95% CI: 0.02-0.06, P = 0.01) and by 0.03 mg·cm2 ·min-1 (0.02-0.05, P = 0.03) at the forearm, compared with negligible changes in control. Training also mediated reductions in cutaneous vasodilation by 9% (6-12) at the chest and by 7% (4-9) at forearm (P≤0.05). Training attenuated hot flush MCAv by 3.4 cm/s (0.7-5.1, P = 0.04) compared with negligible changes in control. Exercise training reduced the self-reported severity of hot-flush by 109 arbitrary units (80-121, P<0.001). These data indicate that exercise training leads to parallel reductions in hot-flush severity and within-flush changes in cutaneous vasodilation, sweating and cerebral blood flo

    The evolution of the human menopause

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    The females of most species die soon after ceasing to reproduce, their purpose in life being to ensure survival of their kin. Human females may live more than one-third of their lives after they cease to reproduce, a property shared by few species, one of which is Orca whales. Orcas have been extensively studied because families live together in stable units or pods and individual whales have distinctive markings, enabling them to be identified. The females survive long after the menopause, one possible reason for this being that the older females provide a survival advantage since they are seen to lead the pods more often than younger females or males, thus providing a survival advantage in times of food shortage. The female lifespan is increasing in most countries worldwide, principally due to decreased infection and maternal mortality. Women are now more active through middle and into older age. Whatever sort of life they wish to lead, women need to be as fit as possible to facilitate healthy aging. Chronic diseases that affect millions of women are cardiovascular disease, osteoporosis, cancer, and dementia. The incidence of all these is increased by obesity, the prevention of which is a major challenge in our society. Hormone therapy may have a place for some women but for many others taking control of their health by lifestyle intervention is a major contributor to disease prevention. It is our duty as doctors to encourage this at every opportunity to help all women live a fruitful and healthy old age

    Nonuniqueness properties of the physical solutions of the Lorentz-Dirac equation

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    The solutions of the Lorentz-Dirac equation are investigated, for the problem of a one-dimensional scattering of a charged particle by a potential barrier, and a phenomenon is found having some similarity to the quantum weak-reflection effect. Namely, there exists an energy strip, slightly above the maximum of the barrier, such that for any given initial energy in the strip there is a certain number of physical (or nonrunaway) solutions of two types, i.e. Those of mechanical type, transmitted beyond the barrier, and those of nonmechanical type, reflected by the barrier. From the mathematical point of view, the existence of this phenomenon is related to the nonuniqueness of the physical solutions of the Lorentz-Dirac equation for given initial data of position and velocity. This in turn is strictly related to a property recently pointed out, namely the asymptotic character of the relevant series expansions occurring for that equation. Correspondingly, the width of the energy strip where the phenomenon occurs is found to decrease exponentially fast, as the small parameter entering the problem tends to zero

    Nuclear DFT analysis of electromagnetic moments in odd near doubly magic nuclei

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    International audienceWe use the nuclear density functional theory to determine nuclear electric quadrupole and magnetic dipole moments in all one-particle and one-hole neighbours of eight doubly magic nuclei. We align angular momenta along the intrinsic axial-symmetry axis with broken time-reversal symmetry, which allows us to explore fully the self-consistent charge, spin, and current polarisation. Spectroscopic moments are determined for symmetry-restored wave functions and compared with available experimental data. We find that the obtained polarisations do not call for using quadrupole- or dipole-moment operators with effective charges or effective g-factors

    Hot flushes, vascular reactivity and the role of the α-adrenergic system

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    Background: Seventy percent of postmenopausal women suffer from hot flushes but the pathophysiology is poorly understood. Proposed mechanisms include altered peripheral vascular reactivity and a narrowed thermoneutral zone. A trigger has not yet been identified; however, the α-adrenergic system, and specifically noradrenaline, has been implicated. &lt;p/&gt;Aim: To assess the role of the α-adrenergic system by studying the effect of clonidine (α-adrenergic agonist) on flushes and cutaneous microvascular perfusion. &lt;p/&gt;Methods: Thirty-two postmenopausal women with severe flushing and 14 non-flushing postmenopausal women were recruited. Cutaneous microvascular perfusion was measured using laser Doppler imaging and endothelial function was assessed by iontophoresis (administration of vasoactive agents through the skin by an electric current) of acetylcholine (ACh – endothelium-dependent) and sodium nitroprusside (SNP – endothelium-independent). In a double-blind, longitudinal, cross-over study, clonidine (an α-adrenergic agonist) was compared to placebo in its ability to modulate this response in the flushing group of women. &lt;p/&gt;Results: The response of the subcutaneous vessels was greater in women who flushed than those who did not (ACh, p &#60; 0.001 and SNP, p = 0.001). However, even though the intensity and number of flushes were decreased by clonidine, there was no difference compared to placebo (p = 0.21) and this ‘placebo effect’ was also noted in perfusion responses (ACh, p = 0.98; SNP, p = 0.50). &lt;p/&gt;Conclusion: There was a significant ‘placebo effect’ for both clinical response and the reactivity of the subcutaneous vessels, making conclusions regarding the role of the α-adrenergic nervous system in hot flushing difficult to determine at a peripheral level. The mechanism for the change in vascular reactivity remains unclear
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