3,523 research outputs found
Some Quantitative Characterizations of Certain Symplectic Groups
Given a finite group , denote by the degree pattern of
and by the set of all order components of . Denote by (resp. ) the number of isomorphism classes of finite
groups satisfying conditions and (resp.
). A finite group is called OD-characterizable
(resp. OC-characterizable) if (resp. ). Let
be a symplectic group over binary field, for which is a
Mersenne prime. The aim of this article is to prove that
A Classical String in Lifshitz-Vaidya Geometry
We study the time evolution of the expectation value of a rectangular Wilson
loop in strongly anisotropic time-dependent plasma using gauge-gravity duality.
The corresponding gravity theory is given by describing time evolution of a
classical string in the Lifshitz-Vaidya background. We show that the
expectation value of the Wilson loop oscillates about the value of the static
potential with the same parameters after the energy injection is over. We
discuss how the amplitude and frequency of the oscillation depend on the
parameters of the theory. In particular, by raising the anisotropy parameter,
we observe that the amplitude and frequency of the oscillation increase.Comment: 19 pages, 5 figure
Sodium benzoate and potassium sorbate preservatives in food stuffs in Iran
A high-performance liquid chromatography method was applied for the determination of the levels of benzoate and sorbate in 400 food samples, including pickled cucumbers, canned tomato pastes, sour cherry jams, soft drinks, fruit juices and dairy products (UF-Feta cheeses, Lighvan cheeses, lactic cheeses, yogurts and doogh). The results showed that 270 (67.5%) of all samples contained benzoate ranging from 11.9 to 288.5 mg kgā»Ā¹ in lactic cheese and fruit juice, respectively. The levels of sorbate in 98 (24.5%) of the samples were 20.1 to 284.3 mg kgā»Ā¹ in doogh and fruit juice, respectively. Moreover, benzoate was detected in all dairy products ranging from 11.9 mg kgā»Ā¹ in lactic cheese to 91.2 mg kgā»Ā¹ in UF-Feta cheese. A low concentration of benzoate could originate naturally, due to specific biochemical mechanisms during cheese, yogurt and doogh maturation. In conclusion, a minimum level for benzoate in dairy products should be defined in the legislation. Ā© 2015 Taylor & Francis
Incorporating family function into chronic pain disability: the role of catastrophizing
Background. Observers' responses to pain are recently investigated to more comprehensively explain chronic pain (CP) and disability. However, the role of family context, defined as interference in roles, communication, and problem-solving, and how (i.e., through which mechanisms) these variables contribute to CP related disability have yet to be examined. Objectives. The aim of the present study is to examine family context in relationship to pain catastrophizing, fear of movement, and depression and its role in understanding CP disability. Three different models were examined. Methods. A total sample of 142 patients with musculoskeletal chronic pain was recruited to examine the role of fear of movement, pain intensity, pain catastrophizing, and depression in relationship to family functioning as predictors of disability. Results. Findings indicated that two models showed acceptable fit, but one of them revealed superior fit indices. Results of the model with superior fit indices indicated that family dysfunction may contribute to catastrophic thinking, which, in turn, contributes to patients' disability through increasing fear of movement and depression. Discussion. The current study provides further support for the notion that the impact of emotional and cognitive variables upon CP-related disability can be better understood when we consider the social context of pain patients and family function in particular
Dielectric Susceptibility and Heat Capacity of Ultra-Cold Glasses in Magnetic Field
Recent experiments demonstrated unexpected, even intriguing properties of
certain glassy materials in magnetic field at low temperatures. We have studied
the magnetic field dependence of the static dielectric susceptibility and the
heat capacity of glasses at low temperatures. We present a theory in which we
consider the coupling of the tunnelling motion to nuclear quadrupoles in order
to evaluate the static dielectric susceptibility. In the limit of weak magnetic
field we find the resonant part of the susceptibility increasing like
while for the large magnetic field it behaves as 1/B. In the same manner we
consider the coupling of the tunnelling motion to nuclear quadrupoles and
angular momentum of tunnelling particles in order to find the heat capacity.
Our results show the Schotky peak for the angular momentum part, and
dependence for nuclear quadrupoles part of heat capacity, respectively. We
discuss whether or not this approach can provide a suitable explanation for
such magnetic properties.Comment: 10 pages, 1 figur
Global limits on kinetic Alfv\'{e}non speed in quasineutral plasmas
Large amplitude kinetic Alfv\'{e}non (exact Alfv\'{e}n soliton) matching
condition is investigated in quasineutral electron-ion and
electron-positron-ion plasmas immersed in a uniform magnetic field. Using the
standard pseudopotential method, the magnetohydrodynamics (MHD) equations are
exactly solved and a global allowed matching condition for propagation of
kinetic solitary waves is derived. It is remarked that, depending on the plasma
parameters, the kinetic solitons can be sub- or super-Alfv\'{e}nic, in general.
It is further revealed that, either upper or lower soliton speed-limit is
independent of fractional plasma parameters. Furthermore, the soliton
propagation angle with respect to that of the uniform magnetic field is found
to play a fundamental role in controlling the soliton matching speed-range.Comment: To be published in Physics of Plasma
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