262 research outputs found
Breaking so(4) symmetry without degeneracy lift
We argue that in the quantum motion of a scalar particle of mass "m" on S^3_R
perturbed by the trigonometric Scarf potential (Scarf I) with one internal
quantized dimensionless parameter, \ell, the 3D orbital angular momentum, and
another, an external scale introducing continuous parameter, B, a loss of the
geometric hyper-spherical so(4) symmetry of the free motion can occur that
leaves intact the unperturbed {\mathcal N}^2-fold degeneracy patterns, with
{\mathcal N}=(\ell +n+1) and n denoting the nodes number of the wave function.
Our point is that although the number of degenerate states for any {\mathcal N}
matches dimensionality of an irreducible so(4) representation space, the
corresponding set of wave functions do not transform irreducibly under any
so(4). Indeed, in expanding the Scarf I wave functions in the basis of properly
identified so(4) representation functions, we find power series in the
perturbation parameter, B, where 4D angular momenta K\in [\ell , {\mathcal
N}-1] contribute up to the order \left(\frac{2mR^2B}{\hbar^2}\right)^{{\mathcal
N}-1-K}. In this fashion, we work out an explicit example on a symmetry
breakdown by external scales that retains the degeneracy. The scheme extends to
so(d+2) for any d.Comment: Prepared for the proceedings of the conference "Lie Theory and Its
Applications In Physics", June 17-23, 2013, Varna, Bulgari
Significance of anatomical variations of the lateral circumflex femoral artery for the tensor fasciae latae flapping
The tensor fasciae latae (TFL) muscle is commonly used in plastic and reconstructive surgery as a transpositional or a free flap, in order to repair different kinds of defects. In most cases its vascularisation is provided by an ascending branch of lateral circumflex femoral artery (LCFA), which gives different numbers of branches and enters the TFL muscle in different manners. The represented study deals with the arterial vascularisation of the TFL muscle: the entrance of the vascular stalk branches; variations of the LCFA bifurcation’s angle; and the skin area of vascularisation. The study was performed on both lower limbs of a 100 foetal and 10 adult cadavers. The LCFA was injected with micropaque solution, afterwards fixed and preserved in 10% formalin solution. Microdissection was performed under magnifying glass and surgical microscope. Analysis of adult cadavers was performed to determine the skin area vascularised by perforating blood vessels from the TFL muscle, by injecting methylene-blue dye into the artery, prior to which all branches of the LCFA, besides the ascending branch, were ligated. The research of a 100 foetal cadavers showed that the LCFA with its ascending branch ensured the blood supply to the muscle. In 85% it gave two branches, the ascending and the descending one, with the angle of bifurcation circa 90o in 73% of cases. The ascending branch can give 0 or more terminal branches, or even form an arterial net. Skin area affected with dye ranged from 18 × 22 cm to 23 × 28 cm and is in positive correlation with the LCFA length and diameter. The understanding of the presented variations have an exceptional significance in planning and applying the TFL flap, especially free flap, in successful repairing and covering the defects, as well as in preventing postoperative complications
Bilateral anatomic variation in the relation of the upper trunk of the brachial plexus to the anterior scalene muscle
The brachial plexus represents a field of many anatomical variations with impor- tant clinical implications, especially in the diagnosis and treatment of the thoracic outlet syndrome (TOS). The case described in this paper presented a novel bilateral variation in the relation of the upper trunk of the brachial plexus to the anterior scalene muscle. The ventral rami of the C5 and C6 spinal nerves perforated the anterior scalene muscle simultaneously through a common opening, and joined to form the upper trunk. Previous literature reports described variations of the brachial plexus and the scalene muscles, as well as the embryological basis for their presence. The case reported herein helps to improve the comprehension of the TOS, as well as the diagnostic and therapeutical approach to this syndrome
Photocatalytic degradation of metoprolol tartrate in suspensions of two TiO2-based photocatalysts with different surface area. Identification of intermediates and proposal of degradation pathways.
This study investigates the efficiency of the photocatalytic degradation of metoprolol tartrate (MET), a widely used β 1-blocker, in TiO 2 suspensions of Wackherr's " Oxyde de titane standard" and Degussa P25. The study encompasses transformation kinetics and efficiency, identification of intermediates and reaction pathways. In the investigated range of initial concentrations (0.01-0.1mM), the photocatalytic degradation of MET in the first stage of the reaction followed approximately a pseudo-first order kinetics. The TiO 2 Wackherr induced a significantly faster MET degradation compared to TiO 2 Degussa P25 when relatively high substrate concentrations were used. By examining the effect of ethanol as a scavenger of hydroxyl radicals (OH), it was shown that the reaction with OH played the main role in the photocatalytic degradation of MET. After 240min of irradiation the reaction intermediates were almost completely mineralized to CO 2 and H 2O, while the nitrogen was predominantly present as NH4+. Reaction intermediates were studied in detail and a number of them were identified using LC-MS/MS (ESI+), which allowed the proposal of a tentative pathway for the photocatalytic transformation of MET as a function of the TiO 2 specimen
Experimental confirmation of efficient island divertor operation and successful neoclassical transport optimization in Wendelstein 7-X
We present recent highlights from the most recent operation phases of Wendelstein 7-X, the most advanced stellarator in the world. Stable detachment with good particle exhaust, low impurity content, and energy confinement times exceeding 100 ms, have been maintained for tens of seconds. Pellet fueling allows for plasma phases with reduced ion-temperature-gradient turbulence, and during such phases, the overall confinement is so good (energy confinement times often exceeding 200 ms) that the attained density and temperature profiles would not have been possible in less optimized devices, since they would have had neoclassical transport losses exceeding the heating applied in W7-X. This provides proof that the reduction of neoclassical transport through magnetic field optimization is successful. W7-X plasmas generally show good impurity screening and high plasma purity, but there is evidence of longer impurity confinement times during turbulence-suppressed phases
Forward modeling of collective Thomson scattering for Wendelstein 7-X plasmas: Electrostatic approximation
In this paper, we present a method for numerical computation of collective Thomson scattering (CTS). We developed a forward
model, eCTS, in the electrostatic approximation and benchmarked it against a full electromagnetic model. Differences between
the electrostatic and the electromagnetic models are discussed. The sensitivity of the results to the ion temperature and the plasma composition is demonstrated. We integrated the model into the Bayesian data analysis framework Minerva and used it for the analysis of noisy synthetic data sets produced by a full electromagnetic model. It is shown that eCTS can be used for the inference of the bulk ion temperature. The model has been used to infer the bulk ion temperature from the first CTS measurements on Wendelstein 7-X.EURATOM 63305
Removing non-stationary, non-harmonic external interference from gravitational wave interferometer data
We describe a procedure to identify and remove a class of non-stationary and
non-harmonic interference lines from gravitational wave interferometer data.
These lines appear to be associated with the external electricity main
supply, but their amplitudes are non-stationary and they do not appear at
harmonics of the fundamental supply frequency. We find an empirical model able
to represent coherently all the non-harmonic lines we have found in the power
spectrum, in terms of an assumed reference signal of the primary supply input
signal. If this signal is not available then it can be reconstructed from the
same data by making use of the coherent line removal algorithm that we have
described elsewhere. All these lines are broadened by frequency changes of the
supply signal, and they corrupt significant frequency ranges of the power
spectrum. The physical process that generates this interference is so far
unknown, but it is highly non-linear and non-stationary. Using our model, we
cancel the interference in the time domain by an adaptive procedure that should
work regardless of the source of the primary interference. We have applied the
method to laser interferometer data from the Glasgow prototype detector, where
all the features we describe in this paper were observed. The algorithm has
been tuned in such a way that the entire series of wide lines corresponding to
the electrical interference are removed, leaving the spectrum clean enough to
detect signals previously masked by them. Single-line signals buried in the
interference can be recovered with at least 75 % of their original signal
amplitude.Comment: 14 pages, 5 figures, Revtex, psfi
Effect of <em>Thymus vulgaris</em> and <em>Bunium persicum</em> essential oils on the oxidative stability of virgin olive oil
Natural antioxidants are becoming a major focus because natural food ingredients are safer than synthetic types. The aim of this study was to investigate the protective effects of Thymus vulgaris and Bunium persicum essential oils (EO) on the oxidation of virgin olive oil (VOO) during accelerated storage. The antioxidant activities of EOs were compared with those of α-tocopherol and BHT. GC/MS analyses revealed that thymol (28.50%), p-cymene (27.14%), carvacrol (18.36%), and γ-terpinene (4.97%) are the main components of T. vulgaris EO, while cuminaldehyde (32.81%), γ-terpinene (16.02%) and p-cymene (14.07%) are the main components of B. persicum EO. Both EOs provided protection for the VOO, inhibiting the formation of primary and secondary oxidation products although T. vulgaris EO showed greater protection against the oxidation process than B. persicum EO. The effect of T. vulgaris essential oil on the oxidation inhibition of VOO was similar to that of BHT. α-Tocopherol showed no measurable effect on improving the oxidative stability of VOO. This study suggests that T. vulgaris and B. persicum EOs can be used to improve the oxidative stability of VOO
Different behaviour of 3-nitrotyrosine and tyrosine toward perfluorinated reagents suitable for the one-step preparation of volatile derivatives
With the view of developing a gas-chromatographic (GC) determination
of the 3-nitrotyrosine (NY)/tyrosine (Y) ratio as a marker of nitro-oxidative
stress, different reagents were tested with the objective of obtaining a
single volatile fluorinated product for each amino acid in a one-step derivatisation
procedure. The heptafluorobutyric anhydride (HFBA)/heptafluorobutanol
(HFBOH) mixture proved unsuccessful for the simultaneous analysis
of NY and Y. The reaction with different chloroformates, isobutyl chlorofomate
(iBuCF) and ethyl chloroformate (EtCF) in the presence of different
perfluorinated alcohols, such as trifluoroethanol (TFEOH) and HFBOH, was
investigated. A combination EtCF/fluorinated alcohols yielded derivatives of
NY and Y as single peaks suitable for the GC determination of the NY/Y ratio.
The different behaviours of the two amino acids in the employed reaction mixtures
and the parameters influencing the results are discussed
154 GHz Collective Thomson Scattering in LHD
Collective Thomson scattering (CTS) was developed by using a 154 GHz gyrotron, and the first data has been obtained. Already, 77 GHz CTS has worked successfully. However, in order to access higher density region, 154 GHz option enhances the usability that reduces the refraction effect, which deteriorates in the local measurements. The system in the down converted frequency was almost identical to the system for 77 GHz. Probing beam, a notch filter, a mixer, and a local oscillator in the receiver system for 77 GHz option were replaced to those for the 154 GHz option. 154 GHz gyrotron was originally prepared for the second harmonic electron cyclotron heating (ECRH) at 2.75 T. However, scattering signal was masked by the second harmonic electron cyclotron emission (ECE) at 2.75 T. Therefore, 154 GHz CTS was operated at 1.375 T with fourth harmonic ECE, and an acceptable signal to noise ratio was obtained. There is a signature of fast ion components with neutral beam (NB) injection. In addition, the CTS spectrum became broader in hydrogen discharge than in deuterium discharge, as the theoretical CTS spectrum expects. This observation indicates a possibility to identify ion species ratio by the 154 GHz CTS diagnostic
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