1,952 research outputs found
Chelonus ocellatus ALEXEEV 1971
No full textChelonus ocellatus ALEXEEV 1971 M a t e r i a l e x a m i n e d: Mazandaran province: Savadkooh, 1, July 2005. G e n e r a l d i s t r i b u t i o n Crimea, Middle Asia, Turkey (AYDOGDU & BEYARSLAN 2002).Published as part of Sakenin, H., Naderian, H., Samin, N., Rastegar, J., Tabari, M., Papp, J. & I, Northern, 2012, On a collection of Braconidae (Hymenoptera) from northern Iran, pp. 1319-1330 in Linzer biologische Beiträge 44 (2) on page 1323, DOI: 10.5281/zenodo.533526
Chelonus ocellatus ALEXEEV 1971
No full textChelonus ocellatus ALEXEEV 1971 M a t e r i a l: Mazandaran province: Savadkooh, Alasht (3), September 2003. G e n e r a l d i s t r i b u t i o n: Crimea,MiddleAsia, Turkey.Published as part of Ghahari, H., Fischer, M., Cetin, O., Beyarslan, A. & Ostovan, H., 2010, A contribution to the braconid wasps (Hymenoptera: Braconidae) from the forests of northern Iran, pp. 621-634 in Linzer biologische Beiträge 42 (1) on page 626, DOI: 10.5281/zenodo.533280
The deuteron spin-dependent structure function g(1)(d) and its first moment
No full textAlexakhin VY, Alexandrov Y, Alexeev GD, et al. The deuteron spin-dependent structure function g(1)(d) and its first moment. Phys.Lett. B. 2007;647(1):8-17.We present a measurement of the deuteron spin-dependent structure function g(1)(d) based on the data collected by the COMPASS experiment at CERN during the years 2002-2004. The data provide an accurate evaluation for Gamma(d)(1), the first moment of g(1)(d) (x), and for the matrix element of the singlet axial current, a(0). The results of QCD fits in the next to leading order (NLO) on all g(1) deep inelastic scattering data are also presented. They provide two solutions with the gluon spin distribution function Delta G positive or negative, which describe the data equally well. In both cases, at Q(2) = 3 (GeV/c)(2) the first moment of Delta G(x) is found to be of the order of 0.2-0.3 in absolute value. (c) 2007 Elsevier B.V. All rights reserved
Income Distribution and Price Controls: Targeting a Social Safety Net During Economic Transition
No full textDuring the ongoing post-communist economic transitions, the relative well-being of many people is changing rapidly, and governments are not well positioned to accurately measure individual living standards. Under such circumstances, continued price controls over basic consumer goods within the state sector, and the associated queuing, can form a serviceable device for targeting poor people for subsidies. With a fixed-price state sector and free-price parallel markets, rich people might choose to avoid queues and shop in the free markets, while poor people would prefer to pay low nominal prices and queue in the state sector. The targeting of subsidies through queues, therefore, can be accomplished even if the government has no information on individual income or living standards. When the alternative to price controls is a poorly targeted explicit social safety net, the resource cost of queues might be more than compensated for by an improvement in the targeting of subsidies.price controls, tax evasion, queue-rationing, economic transition, income distribution
A generating functional approach to the Hubbard model
No full textThe method of generating functional, suggested for
conventional systems by Kadanoff and Baym, is generalized to the
case of strongly correlated systems, described by the Hubbard X
operators. The method has been applied to the Hubbard model with
arbitrary value U of the Coulomb on-site interaction. For the
electronic Green's function constructed for
Fermi-like X operators, an equation using variational
derivatives with respect to the fluctuating fields has been
derived and its multiplicative form has been determined. The
Green's function is characterized by two quantities: the self
energy Σ and the terminal part Λ. For them we have
derived the equation using variational derivatives, whose
iterations generate the perturbation theory near the atomic limit.
Corrections for the electronic self-energy Σ are calculated
up to the second order with respect to the parameter W/U (W
width of the band), and a mean field type approximation was
formulated, including both charge and spin static fluctuations.
This approximation is actually equivalent to the one used in the
method of Composite Operators, and it describes an insulator-metal
phase transition at half filling reasonably well.
The equations for the Bose-like Green's functions have been
derived, describing the collective modes: the magnons and
doublons. The main term in this equation represents variational
derivatives of the electronic Green's function with respect to the
corresponding fluctuating fields. The properties of the poles of
the doublon Green's functions depend on electronic filling. The
investigation of the special case n=1 demonstrates that the
doublon Green's function has a soft mode at the wave vector
, indicating possible instability of the
uniform paramagnetic phase relatively to the two sublattices
charge ordering. However this instability should compete with an
instability to antiferromagnetic ordering.
The generating functional method with the X operators could be
extended to the other models of strongly correlated systems
Search for Production of Single Top Quarks Via t c g and t u g Flavor-Changing-Neutral-Current Couplings
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