1,060 research outputs found
Quantum transport in noncentrosymmetric superconductors and thermodynamics of ferromagnetic superconductors
We consider a general Hamiltonian describing coexistence of itinerant
ferromagnetism, spin-orbit coupling and mixed spin-singlet/triplet
superconducting pairing in the context of mean-field theory. The Hamiltonian is
diagonalized and exact eigenvalues are obtained, thus allowing us to write down
the coupled gap equations for the different order parameters. Our results may
then be applied to any model describing coexistence of any combination of these
three phenomena. As a specific application of our results, we consider
tunneling between a normal metal and a noncentrosymmetric superconductor with
mixed singlet and triplet gaps. The conductance spectrum reveals information
about these gaps in addition to how the influence of spin-orbit coupling is
manifested. We also consider the coexistence of itinerant ferromagnetism and
triplet superconductivity as a model for recently discovered ferromagnetic
superconductors. The coupled gap equations are solved self-consistently, and we
study the conditions necessary to obtain the coexistent regime of
ferromagnetism and superconductivity. Analytical expressions are presented for
the order parameters, and we provide an analysis of the free energy to identify
the preferred system state. Moreover, we make specific predictions concerning
the heat capacity for a ferromagnetic superconductor. In particular, we report
a nonuniversal relative jump in the specific heat, depending on the
magnetization of the system, at the uppermost superconducting phase transition.
[Shortened abstract due to arXiv submission.]Comment: 19 pages, 15 figures (high quality figures available in published
version). Accepted for publication in Phys. Rev.
Extraction and nutritional properties of Solanum nigrum L seed oil
With the aim of diversifying the lipids sources eaten by the African populations and those of Congo Brazzaville in particular, a physicochemical study of Solanum nigrum L seeds was carried out and three chemical methods (Soxhlet, Bligh and Dyer, and Folch) were used to extract the oil. The dry matter content of the seeds is 94.22%. Average lipids content varies between 34.5 and 37.5% dry matter, proteins content is 17% dry matter and crude ash content averages 7.18% dry matter and the principal mineral element is Mg (180 mg/100g). The acid value of the oil is about 2.5, saponification value varies between 157.3 and 190.1, peroxide value is low at 5.13 and iodine is 102.33.The fatty acid compositions of S. nigrum seeds oil shows that it has 67.9% of linoleic acid, indicating its high unsaturation. Apart from linoleic acid, other prominent fatty acids were palmitic, stearic and oleic acids. The following average profile is: 18: 2n-6 > 18: 1 n-9 > 16: 0 > 18: 0. The oil is liquid at room temperature and green in colour. Oil viscosity varies between 20 and 35 mPa.s at 25°C. Three activation energies which vary between 0.8 to 26.58 kJ.mol-1 were determined using Arrhenius’s equation. The melting points estimated by Differential Scanning Calorimetry were found to be between -22.0 and -12.0°C for the Soxhlet and Folch-extracted oils. Bligh and Dyer oil have three melting points at -36.2, -15.2 and 33.7°
Extraction, chemical composition and nutrional characterization of vegetable oils: Case of Amaranthus hybridus (var 1 and 2) of Congo Brazzaville
Amaranthus hybridus is a vegetable which is eaten in Congo Brazzaville and in other countries. Two varieties of A. hybridus seeds (var 1 and 2) were selected for this study. Average oil content varies between 11 and 14%. A. hybridus seeds are also rich in proteins (17%) and minerals. Red oils obtained have a high saponification value (130-190) and the iodine value is between 100 and 113. The quantity of unsaponifiable matter (5 - 7%) in these oils is important. The fatty acids composition gives the following average profile: 18: 2n-6 > 18: 1 n-9 > 16: 0 > 22: 6n-3 > 18: 0. A. hybridus seeds oils also have long chain poly unsaturated fatty acids such as DHA (5.63-21.46%) and the results indicated that the n-6/n-3ratios were 1.48 to 5.63. The triacylglycerols analysis shows that oils extracted by Bligh and Dyer method contains 6 major TAGs in A. hybridus var1: LLnLn › OLL › POL. › OLL › PLL › LLL and Amaranthus hybridus var2: LLnLn › OLL › PLL › POL. › OLL › LLL. The A. hybridus seeds can be used ascattle food and baby complement food. These oils have nutritive and dietetic potentialitie
Further Developments on a Vibration-Free Helium-Hydrogen Sorption Cooler
In our continuous effort on the development of a passively precooled two-stage 4.5 K / 14.5 K helium-hydrogen sorption cooler, a number of important development steps were made. Firstly, an improved high-density activated carbon was used for the fabrication of four new sorption cells. Tests with these new cells showed that because of increased efficiency, the required passive radiator area for this cooler reduced by a factor of 1.3. Secondly, it was shown that this cooler architecture can easily be used to reach lower (or higher) temperatures. Without hardware changes, the cold temperature was reduced from 4.5 K to 3.1 K. Thirdly, long-term experiments were carried out on the cooler. In two separate periods of two and four months of continuous operation, no change at all was observed in the cooler performance. Fourthly, clogging effects were analyzed that occurred after a 15 months storage period of the cooler at 300 K. We concluded that hydrogen diffusion out of the stainless steel components should be prevented. Finally, a design of an integrated compact cooler chain was presented, which consists of a 50 K Stirling cooler and the helium-hydrogen sorption cooler. This package may be used in the future to test the sorption cooler technology in a zero-gravity environment
Abdominal functional electrical stimulation to improve respiratory function after spinal cord injury: a systematic review and meta-analysis
Objectives: Abdominal functional electrical stimulation (abdominal FES) is the application of a train of electrical pulses to the abdominal muscles, causing them to contract. Abdominal FES has been used as a neuroprosthesis to acutely augment respiratory function and as a rehabilitation tool to achieve a chronic increase in respiratory function after abdominal FES training, primarily focusing on patients with spinal cord injury (SCI). This study aimed to review the evidence surrounding the use of abdominal FES to improve respiratory function in both an acute and chronic manner after SCI.
Settings: A systematic search was performed on PubMed, with studies included if they applied abdominal FES to improve respiratory function in patients with SCI.
Methods: Fourteen studies met the inclusion criteria (10 acute and 4 chronic). Low participant numbers and heterogeneity across studies reduced the power of the meta-analysis. Despite this, abdominal FES was found to cause a significant acute improvement in cough peak flow, whereas forced exhaled volume in 1 s approached significance. A significant chronic increase in unassisted vital capacity, forced vital capacity and peak expiratory flow was found after abdominal FES training compared with baseline.
Conclusions: This systematic review suggests that abdominal FES is an effective technique for improving respiratory function in both an acute and chronic manner after SCI. However, further randomised controlled trials, with larger participant numbers and standardised protocols, are needed to fully establish the clinical efficacy of this technique
Hybrid Equation/Agent-Based Model of Ischemia-Induced Hyperemia and Pressure Ulcer Formation Predicts Greater Propensity to Ulcerate in Subjects with Spinal Cord Injury
Pressure ulcers are costly and life-threatening complications for people with spinal cord injury (SCI). People with SCI also exhibit differential blood flow properties in non-ulcerated skin. We hypothesized that a computer simulation of the pressure ulcer formation process, informed by data regarding skin blood flow and reactive hyperemia in response to pressure, could provide insights into the pathogenesis and effective treatment of post-SCI pressure ulcers. Agent-Based Models (ABM) are useful in settings such as pressure ulcers, in which spatial realism is important. Ordinary Differential Equation-based (ODE) models are useful when modeling physiological phenomena such as reactive hyperemia. Accordingly, we constructed a hybrid model that combines ODEs related to blood flow along with an ABM of skin injury, inflammation, and ulcer formation. The relationship between pressure and the course of ulcer formation, as well as several other important characteristic patterns of pressure ulcer formation, was demonstrated in this model. The ODE portion of this model was calibrated to data related to blood flow following experimental pressure responses in non-injured human subjects or to data from people with SCI. This model predicted a higher propensity to form ulcers in response to pressure in people with SCI vs. non-injured control subjects, and thus may serve as novel diagnostic platform for post-SCI ulcer formation. © 2013 Solovyev et al
Direct interaction between the Gulf Stream and the shelfbreak south of New England
© The Author(s), 2012. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 2 (2012): 553, doi:10.1038/srep00553.Sea surface temperature imagery, satellite altimetry, and a surface drifter track reveal an unusual tilt in the Gulf Stream path that brought the Gulf Stream to 39.9°N near the Middle Atlantic Bight shelfbreak—200 km north of its mean position—in October 2011, while a large meander brought Gulf Stream water within 12 km of the shelfbreak in December 2011. Near-bottom temperature measurements from lobster traps on the outer continental shelf south of New England show distinct warming events (temperature increases exceeding 6°C) in November and December 2011. Moored profiler measurements over the continental slope show high salinities and temperatures, suggesting that the warm water on the continental shelf originated in the Gulf Stream. The combination of unusual water properties over the shelf and slope in late fall and the subsequent mild winter may affect seasonal stratification and habitat selection for marine life over the continental shelf in 2012.Profiler data were made available by the Ocean
Observatory Initiative (OOI) during the construction phase of the project. The OOI is
funded by the National Science Foundation and managed by the Consortium for Ocean
Leadership. Drifter data were provided by Tim Shaw and David Calhoun at Cape Fear
Community College.GGGwas supported by NSFGrant OCE-1129125. RET was supported
by the Postdoctoral Scholar Program at the Woods Hole Oceanographic Institution, with
funding provided by the Cooperative Institute for the North Atlantic Region. MA was
supported by the Penzance Endowed Fund in Support of Assistant Scientists
The influences of patient's trust in medical service and attitude towards health policy on patient's overall satisfaction with medical service and sub satisfaction in China
<p>Abstract</p> <p>Background</p> <p>It is widely accepted that patient generates overall satisfaction with medical service and sub satisfaction on the basis of response to patient's trust in medical service and response to patient's attitude towards health policy in China. This study aimed to investigate the correlations between patient's trust in medical service/patient's attitude towards health policy and patient's overall satisfaction with medical service/sub satisfaction in current medical experience and find inspiration for future reform of China's health delivery system on improving patient's overall satisfaction with medical service and sub satisfaction in considering patient's trust in medical service and patient's attitude towards health policy.</p> <p>Methods</p> <p>This study collaborated with the National Bureau of Statistics to collect a sample of 3,424 residents from 17 provinces and municipalities in a 2008 China household survey on patient's trust in medical service, patient's attitude towards health policy, patient's overall satisfaction and sub satisfaction in current medical experience.</p> <p>Results</p> <p>Patient's overall satisfaction with medical service and most kinds of sub satisfaction in current medical experience were significantly influenced by both patient's trust in medical service and patient's attitude towards health policy; among all kinds of sub satisfaction in current medical experience, patient's trust in medical service/patient's attitude towards health policy had the largest influence on patient's satisfaction with medical costs, the influences of patient's trust in medical service/patient's attitude towards health policy on patient's satisfaction with doctor-patient interaction and satisfaction with treatment process were at medium-level, patient's trust in medical service/patient's attitude towards health policy had the smallest influence on patient's satisfaction with medical facilities and hospital environment, while patient's satisfaction with waiting time in hospital was not influenced by patient's trust in medical service/patient's attitude towards health policy.</p> <p>Conclusion</p> <p>In order to improve patient's overall satisfaction with medical service and sub satisfaction in considering patient's trust in medical service and patient's attitude towards health policy, both improving patient's interpersonal trust in medical service from individual's own medical experience/public trust in medical service and improving patient's attitude towards health policy were indirect but effective ways.</p
Observational constraint on generalized Chaplygin gas model
We investigate observational constraints on the generalized Chaplygin gas
(GCG) model as the unification of dark matter and dark energy from the latest
observational data: the Union SNe Ia data, the observational Hubble data, the
SDSS baryon acoustic peak and the five-year WMAP shift parameter. It is
obtained that the best fit values of the GCG model parameters with their
confidence level are ()
, ()
. Furthermore in this model, we can see that the
evolution of equation of state (EOS) for dark energy is similar to quiessence,
and its current best-fit value is with the confidence
level .Comment: 9 pages, 5 figure
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