2,089 research outputs found
The orders of nonsingular derivations of Lie algebras of characteristic two
Nonsingular derivations of modular Lie algebras which have finite
multiplicative order play a role in the coclass theory for pro- groups and
Lie algebras. A study of the set N_p of positive integers which occur as orders
of nonsingular derivations of finite-dimensional non-nilpotent Lie algebras of
positive characteristic p was initiated by Shalev and continued by the present
author. In this paper we continue this study in the case of characteristic two.
Among other results, we prove that any divisor n of 2^k-1 with
belongs to N_2. Our methods consist of elementary arguments
with polynomials over finite fields and a little character theory of finite
groups.Comment: 11 page
Wavelet-Based Prediction for Governance, Diversification and Value Creation Variables
We study the possibility of completing data bases of a sample of governance,
diversification and value creation variables by providing a well adapted method
to reconstruct the missing parts in order to obtain a complete sample to be
applied for testing the ownership-structure/diversification relationship. It
consists of a dynamic procedure based on wavelets. A comparison with Neural
Networks, the most used method, is provided to prove the efficiency of the
here-developed one. The empirical tests are conducted on a set of French firms.Comment: 22 page
Integration of small and medium size farmers by co-operatives in the Hungarian fruit and vegetable sector - a case study
The main co-ordinators/channels used in Hungarian fruit and vegetable supply chain are the following: local market, wholesale markets, production co-operatives, marketing cooperatives, producers organisation, processing industry, wholesalers and retailers. Different retail chains gain a progressively larger share of the fresh fruit and vegetable market. It is very important, therefore, that the farmers have to use marketing channels which could give them the strengths (countervailing power) of more concentrated organisations. In this case study, we examine the integration role of MĂłrakert Purchasing and Service Co-operative, in MĂłrahalom in county CsongrĂĄd which can be found in the southern east part of Hungary. The Morakert co-operative active in the fruit and vegetable sector and it was the first officially acknowledged Producers Organisation (PO) in Hungary. It works as a very successful cooperative (e.g. in terms of increasing annual turnover and membership) thus being a good example for a number of emerging producer organisations.fruit and vegetable, integration, co-operatives, Producers Organisation, Hungary, Agribusiness, Farm Management,
A sufficient condition for a number to be the order of a nonsingular derivation of a Lie algebra
A study of the set N_p of positive integers which occur as orders of
nonsingular derivations of finite-dimensional non-nilpotent Lie algebras of
characteristic p>0 was initiated by Shalev and continued by the present author.
The main goal of this paper is to show the abundance of elements of N_p. Our
main result shows that any divisor n of q-1, where q is a power of p, such that
, belongs to N_p. This extends its special
case for p=2 which was proved in a previous paper by a different method.Comment: 10 pages. This version has been revised according to a referee's
suggestions. The additions include a discussion of the (lower) density of the
set N_p, and the results of more extensive machine computations. Note that
the title has also changed. To appear in Israel J. Mat
Undercoverage of the elderly institutionalized population: The risk of biased estimates and the potentials of weighting
In most social surveys, the elderly institutionalized population is not part of the target population because it
is considered as hard-to-reach and hard-to-interview. The deliberate exclusion of institutionalized elderly
from survey samples might cause bias, like previous studies investigating institutionalized elderly persons
and their transition to institutions implied. We use a Monte Carlo simulation based on cross-national
samples of the Survey of Health, Ageing and Retirement in Europe (SHARE) to test whether the
noncoverage and undercoverage of the elderly institutionalized population lead to biased estimates.
Moreover, we examined to what extent weights could be used to correct for the underrepresentation of the
institutionalized population. Our results show that noncoverage leads to biased estimates in two healthrelated
variables. With respect to undercoverage, the precision of all estimates is better, especially if
weights accounting for the hard-to-survey population are applied
Analysis of Ani s 7 and Ani s 1 allergens as biomarkers of sensitization and allergy severity in human anisakiasis
The high frequency of infection by Anisakis simplex (A. simplex) has led to an increase in IgE sensitization, turning allergy to this parasite a relevant contemporary health problem. Improving the lack of conventional diagnosis test specificity is crucial to better understand these clinical scenarios. Specific IgE (sIgE) to A. simplex extract by ImmunoCAP (Anisakis-sIgE) was determined in sera from 403 blood donors (BD) from Cantabria (North of Spain) of which 51 subjects resulted sensitized. Among these latter, 47 were asymptomatic (sABD). The values of total IgE, prick-test, Anisakis-sIgE, and sIgE to Ani s 1 (anti-rAni s 1) and Ani s 7 (anti-rAni s 7) were compared between 46 sABD and 49 A. simplex allergic patients. The IgE seroprevalence by ImmunoCAP among BD was 12.65%. Allergic patients and sABD showed significant differences in all serum biomarkers evaluated. The area under the curve was assessed for Anisakis-sIgE (0.892), sIgE-rAni s 1 (0.672) and sIgE-rAni s 7 (0.668). After a severe reaction, significantly higher levels of Anisakis-sIgE and sIgE anti-rAni s 1 were detected. Determinations of sIgE by ImmunoCAP, Ani s 1 and Ani s 7 presented different sensitization patterns between allergic and asymptomatic individuals. The Ani s 1 allergen arises as a possible biomarker to detect patients at risk of suffering severe allergic reactions
Relativistic Approximate Solutions for a Two-Term Potential: Riemann-Type Equation
Approximate analytical solutions of a two-term potential are studied for the
relativistic wave equations, namely, for the Klein-Gordon and Dirac equations.
The results are obtained by solving of a Riemann-type equation whose solution
can be written in terms of hypergeometric function \,_{2}F_{1}(a,b;c;z). The
energy eigenvalue equations and the corresponding normalized wave functions are
given both for two wave equations. The results for some special cases including
the Manning-Rosen potential, the Hulth\'{e}n potential and the Coulomb
potential are also discussed by setting the parameters as required.Comment: 6 page
Differential Photoelectron Holography: A New Approach for Three-Dimensional Atomic Imaging
We propose differential holography as a method to overcome the long-standing
forward-scattering problem in photoelectron holography and related techniques
for the three-dimensional imaging of atoms. Atomic images reconstructed from
experimental and theoretical Cu 3p holograms from Cu(001) demonstrate that this
method suppresses strong forward-scattering effects so as to yield more
accurate three-dimensional images of side- and back-scattering atoms.Comment: revtex, 4 pages, 2 figure
- âŠ