1,830 research outputs found
Age characteristics of changes in invertase activity of the mucous membrane of the small intestine
Rats of varying ages were subjected to stress from heat, cold, and hydrocortisone injection. Invertase activity in homogenates of small intestine mucous membranes was studied following sacrifice. Invertase activity was low in young animals, but increased sharply in 30 day old ones, remaining at a relatively constant level until old age. The study concludes that the stress hormone (corticosteroids, etc.) levels in the blood, which affects the formation of enteric enzyme levels and activities, and that age related peculiarities in invertase activity are a consequence of altered hormone status and epitheliocyte sensitivity
Speeding Strings
There is a class of single trace operators in Yang-Mills theory
which are related by the AdS/CFT correspondence to classical string solutions.
Interesting examples of such solutions corresponding to periodic trajectories
of the Neumann system were studied recently. In our paper we study a
generalization of these solutions. We consider strings moving with large
velocities. We show that the worldsheet of the fast moving string can be
considered as a perturbation of the degenerate worldsheet, with the small
parameter being the relativistic factor . The series expansion in
this relativistic factor should correspond to the perturbative expansion in the
dual Yang-Mills theory. The operators minimizing the anomalous dimension in the
sector with given charges correspond to periodic trajectories in the mechanical
system which is closely related to the product of two Neumann systems.Comment: v3: added a reference to the earlier wor
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The View of Russian Students on Whether Psychology is a Science
The Psychology as Science Scale (Friedrich, 1996) was administered to 525 psychology students from nine Russian universities to assess their beliefs about the nature of the discipline. About half of students (49.6%) generally agreed that psychology may be called a scientific discipline. Specifically, 71. 5% of the students agreed that psychology is a natural science, similar to biology, chemistry, and physics, 39. 9% of students agreed that psychological research is important and training in psychological methodology is necessary, and 43.1% of students agreed that human behavior is highly predictable. Students who took three methodology courses shared significantly stronger beliefs in the need for psychological research and the importance of training in methodology compared to students who did not take any methodology courses. Furthermore, students with a specialist degree had significantly stronger beliefs that psychology is a science compared to students who have just finished school. In terms of the effect of students’ career aspirations, students who wanted to be academic psychologists and clinicians had significantly stronger beliefs that psychology is a science compared to students who did not have clarity about their future careers. Regardless of the study limitations, these findings have potential implications for Russian psychology instructors
Used papermaking properties of pulp the compositions of the printing paper
The article presents a study of two kinds of papermaking pulp properties, that is thermomechanical and chemi-thermomechanical. Optimal parameters ofgrinding chemical-thermo-mechanical pulp were defined. Influence of pulp on the structural, mechanical and optical properties of paper samples was studied for offset printing. It has been established that the use of wood pulp in composition does not adversely affect on the structural, mechanical, optical and printing properties of paper
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Eocene–early Oligocene climate and vegetation change in southern China: Evidence from the Maoming Basin
Although the Eocene-Oligocene climate transition marks a critical point in the development of the ‘icehouse’ global climate of the present little is known about this important change in the terrestrial realm at low latitudes. Our palynological study of the Shangcun Formation shows it to be early Oligocene in age: palyno-assemblages in the lower part of the formation indicate a cool interval dominated by conifer pollen in the earliest Oligocene followed by a warmer regime in the second half of the early Oligocene. To quantify middle Eocene to late early Oligocene climate conditions at low (~ 20°N) palaeolatitudes in southern Asia several thousand leaf fossil specimens from the Maoming Basin, southern China, were subjected to a multivariate (CLAMP) analysis of leaf form. For terrestrial palaeoclimate comparisons to be valid the palaeoaltitude at which the proxy data are obtained must be known. We find that leaves preserved in the Youganwo (middle Eocene), Huangniuling (late Eocene) and Shangcun (early Oligocene) formations were likely to have been deposited well above sea level at different palaeoelevations. In the Youganwo Formation fine-grained sediments were deposited at an altitude of ~ 1.5 km, after which the basin dropped to ~ 0.5 km by the time the upper Huangniuling sediments were deposited. The basin floor then rose again by 0.5 km reaching an altitude of approximately 1 km in which the Shangcun Formation fine-grained sediments were accumulated. Within the context of these elevation changes the prevailing climates experienced by the Youganwo, Lower Huangniuling, Upper Huangniuling and Shangcun fossil floras were humid subtropical with hot summers and warm winters, but witnessed a progressive increase in rainfall seasonality. By the early Oligocene rainfall seasonality was similar to that of the modern monsoonal climate of Guangdong Province, southern China. All floras show leaf physiognomic spectra most similar to those growing under the influence of the modern Indonesia-Australia Monsoon, but with no evidence of any adaptation to today's South or East Asia Monsoon regimes. The Upper Huangniuling Flora, rich in dipterocarp plant megafossils, grew in the warmest conditions with the highest cold month mean temperature and at the lowest altitude
Spinning and rotating strings for N=1 SYM theory and brane constructions
We obtain spinning and rotating closed string solutions in AdS_5 \times
T^{1,1} background, and show how these solutions can be mapped onto rotating
closed strings embedded in configurations of intersecting branes in type IIA
string theory. Then, we discuss spinning closed string solutions in the UV
limit of the Klebanov-Tseytlin background, and also properties of classical
solutions in the related intersecting brane constructions in the UV limit. We
comment on extensions of this analysis to the deformed conifold background, and
in the corresponding intersecting brane construction, as well as its relation
to the deep IR limit of the Klebanov-Strassler solution. We briefly discuss on
the relation between type IIA brane constructions and their related M-theory
descriptions, and how solitonic solutions are related in both descriptions.Comment: 35 pages. Dedicated to the memory of Ian I. Kogan. References adde
Model of block media taking into account internal friction
The block medium is modeled by a discrete-periodic spatial lattice of masses
connected by elastic springs and viscous dampers. To describe the viscoelastic
behavior of the interblock layers, a rheological model of internal friction
with two Maxwell elements and one Voigt element with the quality factor of the
material as the determining parameter is proposed. Numerical experiments show
that, within the framework of this interlayer model, it is possible to select
the viscosity and stiffness of the Maxwell and Voigt elements so that the
quality factor of the material differs from the given constant value by no more
than 5%. In the one-dimensional case, within the framework of the proposed
model, the influence of the quality factor on the dispersion properties of a
block medium is studied and it is shown that the greatest effect of the quality
factor on the dispersion is observed in the low-frequency part of the spectrum.
In the three-dimensional case, within the framework of the proposed model, some
geomechanical problems are numerically studied for a block half-space under the
action of a surface concentrated vertical load. Namely, the attenuation of the
velocity amplitudes of surface blocks was studied depending on the Q-factor
under step action and under the action of a Gaussian pulse. In addition, we
study a layer on the surface of a half-space under the action of a concentrated
vertical impulse load in the case when both the layer and the half-space are
block media but have different properties.Comment: 14 pages, 10 figure
Addiction-related genes in gambling disorders:new insights from parallel human and pre-clinical models
Neurobiological research supports the characterization of disordered gambling (DG) as a behavioral addiction. Recently, an animal model of gambling behavior was developed (rat gambling task, rGT), expanding the available tools to investigate DG neurobiology. We investigated whether rGT performance and associated risk gene expression in the rat's brain could provide cross-translational understanding of the neuromolecular mechanisms of addiction in DG. We genotyped tagSNPs (single-nucleotide polymorphisms) in 38 addiction-related genes in 400 DG and 345 non-DG subjects. Genes with P<0.1 in the human association analyses were selected to be investigated in the animal arm to determine whether their mRNA expression in rats was associated with the rat's performance on the rGT. In humans, DG was significantly associated with tagSNPs in DRD3 (rs167771) and CAMK2D (rs3815072). Our results suggest that age and gender might moderate the association between CAMK2D and DG. Moderation effects could not be investigated due to sample power. In the animal arm, only the association between rGT performance and Drd3 expression remained significant after Bonferroni correction for 59 brain regions. As male rats were used, gender effects could not be investigated. Our results corroborate previous findings reporting the involvement of DRD3 receptor in addictions. To our knowledge, the use of human genetics, pre-clinical models and gene expression as a cross-translation paradigm has not previously been attempted in the field of addictions. The cross-validation of human findings in animal models is crucial for improving the translation of basic research into clinical treatments, which could accelerate neurobiological and pharmacological investigations in addictions
Folded Three-Spin String Solutions in AdS_5 x S^5
We construct a spinning closed string solution in AdS_5 x S^5 which is folded
in the radial direction and has two equal spins in AdS_5 and a spin in S^5. The
energy expression of the three-spin solution specified by the folding and
winding numbers for the small S^5 spin shows a logarithmic behavior and a
one-third power behavior of the large total AdS_5 spin, in the long string and
in the short string located near the boundary of AdS_5 respectively. It
exhibits the non-regular expansion in the 't Hooft coupling constant, while it
takes the regular one when the S^5 spin becomes large.Comment: 14 pages, LaTeX, no figures, a reference adde
Multi-spin strings on AdS(5)xT(1,1) and operators of N=1 superconformal theory
We study rotating strings with multiple spins in the background of
, which is dual to a superconformal field
theory with global symmetry via the AdS/CFT
correspondence. We analyse the limiting behaviour of macroscopic strings and
discuss the identification of the dual operators and how their anomalous
dimensions should behave as the global charges vary. A class of string
solutions we find are dual to operators in SU(2) subsector, and our result
implies that the one-loop planar dilatation operator restricted to the SU(2)
subsector should be equivalent to the hamiltonian of the integrable Heisenberg
spin chain.Comment: 8 pages, revtex4, twocolum
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