12,452 research outputs found
Comparison of the TaqMan and LightCycler systems in pharmacogenetic testing: evaluation of the CYP2C9*2/*3 polymorphisms.
Background: Pharmacogenetic testing for drugmetabolizing enzymes is not yet widely used in clinical practice. Methods: In an attempt to facilitate the application of this procedure, we have compared two real-time PCRbased methods, the TaqMan_ and the LightCycler_ for the pharmacogenetic evaluation of CYP2C9*2/*3 polymorphisms. Results and Conclusion: Both procedures are suitable for pharmacogenetic studies. The TaqMan procedure was less expensive in terms of cost per sample, but the TaqMan apparatus is more expensive than the LightCycler apparatus
Testicular endocrine activity is upregulated by D-Aspartic acid in the green frog Rana esculenta
This study investigated the involvement of D-aspartic acid (D-Asp) in testicular steroidogenesis of the green frog Rana esculenta and its effect on stimulation of thumb pad morphology and glandular activity, a typical testosterone-dependent secondary sexual characteristic in this amphibian species. In the testis, D-Asp concentrations vary significantly during the reproductive cycle: they are low in pre- and post-reproductive periods, but reach peak levels in the reproductive period (140-236 nmol/g wet tissue). Moreover, the concentrations of D-Asp in the testis through the sexual cycle positively match the testosterone levels in the gonad and the plasma. The racemase activity evaluated during the cycle expresses its peak when D-Asp and testosterone levels are highest, that is, during the reproductive period, confirming the synthesis of D-Asp from L-Asp by an aspartate racemase. Short-term in vivo experiments consisting of a single injection of D-Asp (2.0 micro mol/g body weight) demonstrated that this amino acid accumulates significantly in the testis, and after 3 h its uptake is coupled with a testosterone increase in both testis and plasma. Moreover, within 18 h of amino acid administration, the D-Asp concentration in the testis decreased along with the testosterone titer to prestimulation levels. Other amino acids (L-Asp, D-Glu and L-Glu) used instead of D-Asp were ineffective, confirming that the significant increase in testicular testosterone was a specific feature of this amino acid. In long-term experiments, D-Asp had been administered chronically to frogs caught during the three phases of the reproductive cycle, inducing testosterone increase and 17beta-estradiol decrease in the gonad during the pre- and post-reproductive period, and vice versa during the reproductive period
Matrix algebras in quasi-newtonian algorithms for optimal learning in multi-layer perceptrons
In this work the authors implement in a Multi-Layer Perceptron (MLP) environment a new class of quasi-newtonian (QN) methods. The algorithms proposed in the present paper use in the iterative scheme of a generalized BFGS-method a family of matrix algebras, recently introduced for displacement decompositions and for optimal preconditioning. This novel approach allows to construct methods having an O(n log_2 n) complexity. Numerical experiences compared with the performances of the best QN-algorithms known in the literature confirm the effectiveness of these new optimization techniques
Adaptive matrix algebras in unconstrained minimization
In this paper we study adaptive L(k)QNmethods, involving special matrix algebras of low complexity, to solve general (non-structured) unconstrained minimization problems. These methods, which generalize the classical BFGS method, are based on an iterative formula which exploits, at each step, an ad hocchosen matrix algebra L(k). A global convergence result is obtained under suitable assumptions on f
Six Years of ScoX-1 Monitoring with BeppoSAX Wide Field Cameras
We performed a systematic analysis of 54 Wide Field Camera (WFC) observations
of ScoX-1 available in the BeppoSAX public archive. Observations span over the
six years of BeppoSAX mission lifetime and include 690 hr of data. We searched
for shifts and shape changes of the Z pattern in the color-color diagrams. We
find that the Z pattern occupies most of the time the same locus in the
color-color diagram. There are however a few exceptions, which are discussed in
detail.Comment: 4 Pages, 4 figures. To appear in Proc. of the BeppoSAX Symposium:
"The Restless High-Energy Universe", E.P.J. van den Heuvel, J.J.M. in 't
Zand, and R.A.M.J. Wijers (Eds
Isolation of gravitational waves from displacement noise and utility of a time-delay device
Interferometers with kilometer-scale arms have been built for
gravitational-wave detections on the ground; ones with much longer arms are
being planned for space-based detection. One fundamental motivation for long
baseline interferometry is from displacement noise. In general, the longer the
arm length L, the larger the motion the gravitational-wave induces on the test
masses, until L becomes comparable to the gravitational wavelength. Recently,
schemes have been invented, in which displacement noises can be evaded by
employing differences between the influence of test-mass motions and that of
gravitational waves on light propagation. However, in these schemes, such
differences only becomes significant when L approaches the gravitational
wavelength, and shot-noise limited sensitivity becomes worse than that of
conventional configurations by a factor of at least (f L/c)^(-2), for f<c/L.
Such a factor, although can be overcome theoretically by employing high optical
powers, makes these schemes quite impractical. In this paper, we explore the
use of time delay in displacement-noise-free interferometers, which can improve
their shot-noise-limited sensitivity at low frequencies, to a factor of (f
L/c)^(-1) of the shot-noise-limited sensitivity of conventional configurations.Comment: 10 pages, 12 figures, a proceeding for the Spanish Relativity Meeting
ERE 200
Performance of the diamond active target prototype for the PADME experiment at the DANE BTF
The PADME experiment at the DANE Beam-Test Facility (BTF) is designed
to search for the gauge boson of a new interaction in the process
ee+, using the intense positron beam hitting a
light target. The , usually referred as dark photon, is assumed to
decay into invisible particles of a secluded sector and it can be observed by
searching for an anomalous peak in the spectrum of the missing mass measured in
events with a single photon in the final state. The measurement requires the
determination of the 4-momentum of the recoil photon, performed by a
homogeneous, highly segmented BGO crystals calorimeter. A significant
improvement of the missing mass resolution is possible using an active target
capable to determine the average position of the positron bunch with a
resolution of less than 1 mm. This report presents the performance of a real
size PADME active target made of a thin (50 m) diamond
sensor, with graphitic strips produced via laser irradiation on both sides. The
measurements are based on data collected in a beam test at the BTF in November
2015.Comment: 7 pages, 10 figure
Variation in grouping patterns, mating systems and social structure: what socio-ecological models attempt to explain
Socio-ecological models aim to predict the variation in social systems based on a limited number of ecological parameters. Since the 1960s, the original model has taken two paths: one relating to grouping patterns and mating systems and one relating to grouping patterns and female social structure. Here, we review the basic ideas specifically with regard to non-human primates, present new results and point to open questions. While most primates live in permanent groups and exhibit female defence polygyny, recent studies indicate more flexibility with cooperative male resource defence occurring repeatedly in all radiations. In contrast to other animals, the potential link between ecology and these mating systems remains, however, largely unexplored. The model of the ecology of female social structure has often been deemed successful, but has recently been criticized. We show that the predicted association of agonistic rates and despotism (directional consistency of relationships) was not supported in a comparative test. The overall variation in despotism is probably due to phylogenetic grade shifts. At the same time, it varies within clades more or less in the direction predicted by the model. This suggests that the model's utility may lie in predicting social variation within but not across clades
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