498 research outputs found
Vertical Coordination by Contracts in Agribusiness - An Empirical Research in the Hungarian Dairy Sector
In some cases spot markets failure to govern to whole or a part of the marketing channel effectively and contractual relations are gaining more importance. It is especially true in case of agricultural markets, since these markets became more differentiated and market players are vulnerable in most of the cases. Examination of Hungarian dairy sector is an actual issue, so that one could understand how contractual systems work in the situation when crises appear thanks to governance insufficiency. Our research’s aims are to present a theoretically structured framework of contracting arrangements of milk producers based on Transaction Cost Economics’ (TCE) predictions and economics of contracting and an empirical analysis of the key determinants of governance structure between farmers and dairy processors in Hungary. The source of the research is a theoretical argument based partly on review of Hungarian and international literature on relevant market channels, economics of contracting and governance structures. These gave the theoretical determinants of testable prepositions. In the framework of a postal survey in the second quarter of 2005 we carried out a survey among milk producers. A total of 300 questionnaires containing closed and open questions were sent out for milk producers, 65 of them could have been evaluated. The results have been structured, electronically converted for applying SPSS-software. The data base has been analysed by employing multivariate techniques (cluster analysis, linear regression, multidimensional scaling, etc). First, to be able to decide the number of clusters, we applied a hierarchical clustering. The formation of starting clusters was made by giving the number of the future groups which based on hierarchical cluster method and dendrogram. Hence asset specific investment, price determination and bargaining power proved to be significant in dividing the cases into three groups focusing on governance structure. We revealed the main characteristics of clusters focusing on con-tracting attributes. Groups’ means comparison obtains the result that there is no significant difference in partner change, neither in the whole sample nor in the sub-groups. Unlike from this, the reasons for selling to a particular buyer are different in the clusters, the most important factors are reliability, valid contract and the ones based on geographic reasons. The variables mentioned above were suitable for further investigations, so with the help of linear regression we attempted to see their effect on the contract period. Taking into consideration the t-values of the variables, neither asset specific investment and bargaining power, nor price determination have role in the explanation of contract period. Since the variables applied in the whole survey measure same theoretical concepts, we had the possibility to reduce their number by multidimensional scaling. The aim of this scaling is to gain information about the differences among the respondents reducing the dimensions of the variables. The goodness of fit was good in case of three and two dimensions, so we found that the six-dimensional space can be reduced into two or three dimensions without giving up the differences among cases.Contracts, dairy sector, governance structure, vertical co-ordination, agribusiness, producers’ group, co-operation, transaction cost economics, Hungary
Mean-Field- and Classical Limit of Many-Body Schr\"odinger Dynamics for Bosons
We present a new proof of the convergence of the N-particle Schroedinger
dynamics for bosons towards the dynamics generated by the Hartree equation in
the mean-field limit. For a restricted class of two-body interactions, we
obtain convergence estimates uniform in the Planck constant , up to an
exponentially small remainder. For h=0, the classical dynamics in the
mean-field limit is given by the Vlasov equation.Comment: Latex 2e, 18 page
The analytic structure of 2D Euler flow at short times
Using a very high precision spectral calculation applied to the
incompressible and inviscid flow with initial condition , we find that the width of its analyticity
strip follows a law at short times over eight decades. The
asymptotic equation governing the structure of spatial complex-space
singularities at short times (Frisch, Matsumoto and Bec 2003, J.Stat.Phys. 113,
761--781) is solved by a high-precision expansion method. Strong numerical
evidence is obtained that singularities have infinite vorticity and lie on a
complex manifold which is constructed explicitly as an envelope of analyticity
disks.Comment: 19 pages, 14 figures, published versio
Ideal evolution of MHD turbulence when imposing Taylor-Green symmetries
We investigate the ideal and incompressible magnetohydrodynamic (MHD)
equations in three space dimensions for the development of potentially singular
structures. The methodology consists in implementing the four-fold symmetries
of the Taylor-Green vortex generalized to MHD, leading to substantial computer
time and memory savings at a given resolution; we also use a re-gridding method
that allows for lower-resolution runs at early times, with no loss of spectral
accuracy. One magnetic configuration is examined at an equivalent resolution of
points, and three different configurations on grids of
points. At the highest resolution, two different current and vorticity sheet
systems are found to collide, producing two successive accelerations in the
development of small scales. At the latest time, a convergence of magnetic
field lines to the location of maximum current is probably leading locally to a
strong bending and directional variability of such lines. A novel analytical
method, based on sharp analysis inequalities, is used to assess the validity of
the finite-time singularity scenario. This method allows one to rule out
spurious singularities by evaluating the rate at which the logarithmic
decrement of the analyticity-strip method goes to zero. The result is that the
finite-time singularity scenario cannot be ruled out, and the singularity time
could be somewhere between and More robust conclusions will
require higher resolution runs and grid-point interpolation measurements of
maximum current and vorticity.Comment: 18 pages, 13 figures, 2 tables; submitted to Physical Review
Relative entropy and the stability of shocks and contact discontinuities for systems of conservation laws with non BV perturbations
We develop a theory based on relative entropy to show the uniqueness and L^2
stability (up to a translation) of extremal entropic Rankine-Hugoniot
discontinuities for systems of conservation laws (typically 1-shocks, n-shocks,
1-contact discontinuities and n-contact discontinuities of large amplitude)
among bounded entropic weak solutions having an additional trace property. The
existence of a convex entropy is needed. No BV estimate is needed on the weak
solutions considered. The theory holds without smallness condition. The
assumptions are quite general. For instance, strict hyperbolicity is not needed
globally. For fluid mechanics, the theory handles solutions with vacuum.Comment: 29 page
Determinants of The Fear of The Pandemic and Its Effect on Voting Behavior Among Young Adult Filipinos in The Next Presidential Election
With COVID-19 severely impacting several aspects of society, the upcoming 2022 Philippine Presidential Elections will be the first to take place under such unique circumstances. This study provides information on how various determinants of fear of COVID-19 affect the voting behavior of young adult Filipinos. This study utilized a survey consisting of five sections composed of sociodemographic questionnaire, Multidimensional Scale of Perceived Social Support, Core Dimensions of Spirituality Questionnaire, Fear of COVID-19 Scale and a question about political participation. The results showed that individuals with a higher level of social support and higher level of spirituality were more likely to conform to the political ideals of their respective environments (i.e. family & religious institutions) and were more likely to participate in the elections, along with individuals with higher levels of fea
Quasivariational solutions for first order quasilinear equations with gradient constraint
We prove the existence of solutions for an evolution quasi-variational
inequality with a first order quasilinear operator and a variable convex set,
which is characterized by a constraint on the absolute value of the gradient
that depends on the solution itself. The only required assumption on the
nonlinearity of this constraint is its continuity and positivity. The method
relies on an appropriate parabolic regularization and suitable {\em a priori}
estimates. We obtain also the existence of stationary solutions, by studying
the asymptotic behaviour in time. In the variational case, corresponding to a
constraint independent of the solution, we also give uniqueness results
The Hartree limit of Born's ensemble for the ground state of a bosonic atom or ion
The non-relativistic bosonic ground state is studied for quantum N-body
systems with Coulomb interactions, modeling atoms or ions made of N "bosonic
point electrons" bound to an atomic point nucleus of Z "electron" charges,
treated in Born--Oppenheimer approximation. It is shown that the (negative)
ground state energy E(Z,N) yields the monotonically growing function (E(l N,N)
over N cubed). By adapting an argument of Hogreve, it is shown that its limit
as N to infinity for l > l* is governed by Hartree theory, with the rescaled
bosonic ground state wave function factoring into an infinite product of
identical one-body wave functions determined by the Hartree equation. The proof
resembles the construction of the thermodynamic mean-field limit of the
classical ensembles with thermodynamically unstable interactions, except that
here the ensemble is Born's, with the absolute square of the ground state wave
function as ensemble probability density function, with the Fisher information
functional in the variational principle for Born's ensemble playing the role of
the negative of the Gibbs entropy functional in the free-energy variational
principle for the classical petit-canonical configurational ensemble.Comment: Corrected version. Accepted for publication in Journal of
Mathematical Physic
Internal Anisotropy of Collision Cascades
We investigate the internal anisotropy of collision cascades arising from the
branching structure. We show that the global fractal dimension cannot give an
adequate description of the geometrical structure of cascades because it is
insensitive to the internal anisotropy. In order to give a more elaborate
description we introduce an angular correlation function, which takes into
account the direction of the local growth of the branches of the cascades. It
is demonstrated that the angular correlation function gives a quantitative
description of the directionality and the interrelation of branches. The power
law decay of the angular correlation is evidenced and characterized by an
exponent and an angular correlation length different from the radius of
gyration. It is demonstrated that the overlapping of subcascades has a strong
effect on the angular correlation.Comment: RevteX, 8 pages, 6 .eps figures include
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