441 research outputs found
Dual-release hydrocortisone improves hepatic steatosis in patients with secondary adrenal insufficiency: A real-life study
Background: Conventional glucocorticoid treatment has a significant impact on liver in patients with adrenal insufficiency. Dual-release hydrocortisone (DR-HC) provides physiological cortisol exposure, leading to an improvement in anthropometric and metabolic parameters. We aimed to evaluate the effects of 12-month DR-HC treatment on the hepatic steatosis index (HSI), a validated surrogate index of hepatic steatosis, in patients with secondary adrenal insufficiency (SAI). Methods: A total of 45 patients with hypopituitarism, 22 with hypogonadism, hypothyroidism, ACTH, and GH deficiencies, and 23 with hypogonadism, hypothyroidism, and ACTH deficiency, on replacement therapy for all the pituitary deficiencies, were switched from conventional hydrocortisone to DR-HC. At baseline and after 12 months, glucose and insulin levels, surrogate estimates of insulin sensitivity, and hepatic steatosis were evaluated through ultrasonography and HSI. Results: At diagnosis, ultrasonography documented steatosis in 31 patients (68.8%) while 33 (73.3%) showed high HSI. Hydrocortisone (HC) dose (beta = 1.231, p = 0.010), insulin resistance index (HOMA-IR) (beta = 1.431, p = 0.002), and insulin sensitivity index (ISI)-Matsuda (beta = -1.389, p = 0.034) were predictors of HSI at baseline. After 12 months of DR-HC, a significant decrease in body mass index (BMI) (p = 0.008), waist circumference (WC) (p = 0.010), fasting insulin (p = 0.041), HOMA-IR (p = 0.047), HSI (p < 0.001) and number of patients with HSI > 36 (p = 0.003), and a significant increase in sodium (p < 0.001) and ISI-Matsuda (p = 0.031) were observed. HOMA-IR (beta = 1.431, p = 0.002) and ISI-Matsuda (beta = -9.489, p < 0.001) were identified as independent predictors of HSI at 12 months. Conclusions: In adults with SAI, DR-HC is associated with an improvement in HSI, regardless of the dose used, mainly related to an improvement in insulin sensitivity
Baryon structure in a quark-confining non-local NJL model
We study the nucleon and diquarks in a non-local Nambu-Jona-Lasinio model.
For certain parameters the model exhibits quark confinement, in the form of a
propagator without real poles. After truncation of the two-body channels to the
scalar and axial-vector diquarks, a relativistic Faddeev equation for nucleon
bound states is solved in the covariant diquark-quark picture. The dependence
of the nucleon mass on diquark masses is studied in detail. We find parameters
that lead to a simultaneous reasonable description of pions and nucleons. Both
the diquarks contribute attractively to the nucleon mass. Axial-vector diquark
correlations are seen to be important, especially in the confining phase of the
model. We study the possible implications of quark confinement for the
description of the diquarks and the nucleon. In particular, we find that it
leads to a more compact nucleon.Comment: 21 pages (RevTeX), 18 figures (eps
A cooperative mobile robot and manipulator system (Co-MRMS) for transport and lay-up of fibre plies in modern composite material manufacture
Composite materials are widely used in industry due to their light weight and specific performance. Currently, composite manufacturing mainly relies on manual labour and individual skills, especially in transport and lay-up processes, which are time consuming and prone to errors. As part of a preliminary investigation into the feasibility of deploying autonomous robotics for composite manufacturing, this paper presents a case study that investigates a cooperative mobile robot and manipulator system (Co-MRMS) for material transport and composite lay-up, which mainly comprises a mobile robot, a fixed-base manipulator and a machine vision sub-system. In the proposed system, marker-based and Fourier transform-based machine vision approaches are used to achieve high accuracy capability in localisation and fibre orientation detection respectively. Moreover, a particle-based approach is adopted to model material deformation during manipulation within robotic simulations. As a case study, a vacuum suction-based end-effector model is developed to deal with sagging effects and to quickly evaluate different gripper designs, comprising of an array of multiple suction cups. Comprehensive simulations and physical experiments, conducted with a 6-DOF serial manipulator and a two-wheeled differential drive mobile robot, demonstrate the efficient interaction and high performance of the Co-MRMS for autonomous material transportation, material localisation, fibre orientation detection and grasping of deformable material. Additionally, the experimental results verify that the presented machine vision approach achieves high accuracy in localisation (the root mean square error is 4.04 mm) and fibre orientation detection (the root mean square error is 1.84 18) and enables dealing with uncertainties such as the shape and size of fibre plies
Predictive factors of polycystic ovary syndrome in girls with precocious pubarche
Objective: The aim of this study is to clarify, in girls with premature pubarche (PP), the influence of premature androgenization on the prevalence of polycystic ovary syndrome (PCOS). Design and patients: Ninety-nine PP girls, 63 who developed PCOS and 36 who did not develop PCOS, were retrospectively included. Clinical, anthropometric, and metabolic parameters were evaluated at the time of diagnosis of PP and after 10 years from menarche to find predictive factors of PCOS. Results: Young females with PP showed a PCOS prevalence of 64% and showed a higher prevalence of familial history of diabetes (P = 0.004) and a lower prevalence of underweight (P = 0.025) than PP-NO-PCOS. In addition, girls with PP-PCOS showed higher BMI (P < 0.001), waist circumference (P < 0.001), total testosterone (P = 0.026), visceral adiposity index (VAI) (P = 0.013), total cholesterol (P < 0.001), LDL-cholesterol (P < 0.001), non-HDL cholesterol (P < 0.001) and lower age of menarche (P = 0.015), ISI-Matsuda (P < 0.001), DIo (P = 0.002), HDL cholesterol (P = 0.026) than PP-NO-PCOS. Multivariate analysis showed that WC (P = 0.049), ISI-Matsuda (P < 0.001), oral disposition index (DIo) (P < 0.001), VAI (P < 0.001), total testosterone (P < 0.001) and LDL-cholesterol (P < 0.001) are independent predictive factors for PCOS in girls with PP. Conclusions: Our study established a strong association between multiple risk factors and development of PCOS in PP girls. These risk factors are predominantly related to the regulation of glucose, lipid, and androgen metabolism. Among these factors, WC, ISI-Matsuda, DIo, VAI, total testosterone, and LDL-cholesterol predict PCOS
The Correlation between X-ray spectral slope and FeKalpha line energy in radio-quiet active galactic nuclei
A significant correlation between FeKalpha line energy and X-ray spectral
slope has been discovered among radio-quiet active galactic nuclei. The
ionization stage of the bulk of the FeKalpha emitting material is not the same
in all active galactic nuclei and is related to the shape of the X-ray
continua. Active galactic nuclei with a steep X-ray spectrum tend to have a
fluorescence FeKalpha line from highly ionized material. In the narrow-line
Seyfert 1 galaxies with steeper X-ray spectrum (Gamma_X > 2.1), the FeKalpha
line originates from highly ionized material. In the Seyfert 1 galaxies and
quasars with flatter X-ray spectrum (Gamma_X < 2.1), bulk of the FeKalpha
emission arises from near neutral or weakly ionized material. The correlation
is an important observational characteristic related to the accretion process
in radio quiet active galactic nuclei and is driven by a fundamental physical
parameter which is likely to be the accretion rate relative to the Eddington
rate.Comment: 4 pages, To apear in ApJ Letter
Comprehensive simulation of cooperative robotic system for advanced composite manufacturing: A case study
Composite materials are widely used because of their light weight and high strength properties. They are typically made up of multi-directional layers of high strength fibres, connected by a resin. The manufacturing of composite parts is complex, time-consuming and prone to errors. This work investigates the use of robotics in the field of composite material manufacturing, which has not been well investigated to date (particularly in simulation). Effective autonomous material transportation, accurate localization and limited material deformation during robotic grasping are required for optimum placement and lay-up. In this paper, a simulation of a proposed cooperative robotic system, which integrates an autonomous mobile robot with a fixed-base manipulator, is presented. An approach based on machine vision is adopted to accurately track the position and orientation of the fibre plies. A simulation platform with a built-in physics engine is used to simulate material deformation under gravity and external forces. This allows realistic simulation of robotic manipulation for raw materials. The results demonstrate promising features of the proposed system. A root mean square error of 9.00 mm for the estimation of the raw material position and 0.05 degrees for the fibre orientation detection encourages further research for developing the proposed robotic manufacturing system
Spatially resolved XMM-Newton analysis and a model of the nonthermal emission of MSH 15-52
We present an X-ray analysis and a model of the nonthermal emission of the
pulsar wind nebula (PWN) MSH15-52. We analyzed XMM-Newton data to obtain the
spatially resolved spectral parameters around the pulsar PSRB1509-58. A
steepening of the fitted power-law spectra and decrease in the surface
brightness is observed with increasing distance from the pulsar. In the second
part of this paper, we introduce a model for the nonthermal emission, based on
assuming the ideal magnetohydrodynamic limit. This model is used to constrain
the parameters of the termination shock and the bulk velocity of the leptons in
the PWN. Our model is able to reproduce the spatial variation of the X-ray
spectra. The parameter ranges that we found agree well with the parameter
estimates found by other authors with different approaches. In the last part of
this paper, we calculate the inverse Compton emission from our model and
compare it to the emission detected with the H.E.S.S. telescope system. Our
model is able to reproduce the flux level observed with H.E.S.S., but not the
spectral shape of the observed TeV {\gamma}-ray emission.Comment: Accepted for publication in A&A, 9 pages, 15 figure
Green Bank Telescope Studies of Giant Pulses from Millisecond Pulsars
We have conducted a search for giant pulses from four millisecond pulsars
using the 100m Green Bank Telescope. Coherently dedispersed time-series from
PSR J0218+4232 were found to contain giant pulses of very short intrinsic
duration whose energies follow power-law statistics. The giant pulses are in
phase with the two minima of the radio integrated pulse profile but are phase
aligned with the peaks of the X-ray profile. Historically, individual pulses
more than 10-20 times the mean pulse energy have been deemed to be ``giant
pulses''. As only 4 of the 155 pulses had energies greater than 10 times the
mean pulse-energy, we argue the emission mechanism responsible for giant pulses
should instead be defined through: (a) intrinsic timescales of microsecond or
nanosecond duration; (b) power-law energy statistics; and (c) emission
occurring in narrow phase-windows coincident with the phase windows of
non-thermal X-ray emission. Four short-duration pulses with giant-pulse
characteristics were also observed from PSR B1957+20. As the inferred magnetic
fields at the light cylinders of the millisecond pulsars that emit giant pulses
are all very high, this parameter has previously been considered to be an
indicator of giant pulse emissivity. However, the frequency of giant pulse
emission from PSR~B1957+20 is significantly lower than for other millisecond
pulsars that have similar magnetic fields at their light cylinders. This
suggests that the inferred magnetic field at the light cylinder is a poor
indicator of the rate of emission of giant pulses.Comment: 26 pages, 4 figures, accepted to Ap
Functional Characteristics and Coping Strategies among Rugby Athletes: A Cluster Analysis Approach
The developing domain of mental health in sports has gained much interest, acknowledging its pivotal role in athlete performance and well-being. The aim of this research is to provide a quantitative description concerning the levels of mental health, physical activity, cognitive fusion, cognitive flexibility, and coping strategies that characterize rugby athletes by using a data-driven approach. A total of 92 rugby athletes took part in this study and filled out a set of self-administered questionnaires. A correlational analysis showed that general well-being was positively associated with years spent playing rugby (r = 0.23) and coping mechanisms (r = 0.29). Athletes’ well-being was also negatively correlated with cognitive inflexibility (r = −0.41) and cognitive fusion (r = −0.39). A k-means cluster analysis identified two unique groups: group 1, characterized by higher levels of psychological well-being, lower levels of physical activity, greater cognitive flexibility, improved coping techniques, and reduced cognitive fusion, and group 2, which exhibits opposite characteristics. The discrepancies observed in psychological characteristics such as coping strategies, cognitive fusion, and cognitive inflexibility highlight their potential impact on the general health of rugby players. To comprehend the complex interplay between psychological and physical elements in rugby athletes, long-term studies with larger samples are crucial
4U 0115+63 from RXTE and INTEGRAL Data: Pulse Profile and Cyclotron Line Energy
We analyze the observations of the transient X-ray pulsar 4U 0115+63 with the
RXTE and INTEGRAL observatories in a wide X-ray (3-100 keV) energy band during
its intense outbursts in 1999 and 2004. The energy of the fundamental harmonic
of the cyclotron resonance absorption line near the maximum of the X-ray flux
from the source (luminosity range 5x10^{37} - 2x10^{38} erg/s) is ~11 keV. When
the pulsar luminosity falls below ~5x10^{37} erg/s, the energy of the
fundamental harmonic is displaced sharply toward the high energies, up to ~16
keV. Under the assumption of a dipole magnetic field configuration, this change
in cyclotron harmonic energy corresponds to a decrease in the height of the
emitting region by ~2 km, while other spectral parameters, in particular, the
cutoff energy, remain essentially constant. At a luminosity ~7x10^{37} erg/s,
four almost equidistant cyclotron line harmonics are clearly seen in the
spectrum. This suggests that either the region where the emission originates is
compact or the emergent spectrum from different (in height) segments of the
accretion column is uniform. We have found significant pulse profile variations
with energy, luminosity, and time. In particular, we show that the profile
variations from pulse to pulse are not reduced to a simple modulation of the
accretion rate specified by external conditions.Comment: 30 pages, 13 figures, Astronomy Letters, 33, 368 (2007
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