DEVELOPMENT OF SMES IN AGRIBUSINESS OF VOJVODINA COMMUNES - STATE AND PERSPECTIVES

Agriculture as the economic sector is an important factor of economic development of Serbia and an important part of economic structure. Serbia has agrarian resources (land, climate and water) that are not used enough, and therefore, represent a significant economic potential for further development. Vojvodina is the best-developed economic region of the Republic of Serbia, with dominant role of agricultural production. The main economic potential of Vojvodina development is, among other things, the strengthening and improvement of agriculture in the private sector. Economic potential of agriculture impose the need to analyze this situation in the field of small and medium sized entrepreneurship as the bearer of the future development of agriculture in Vojvodina. Cluster analysis is a method that will determine how to group communes in Vojvodina according to the level of development of small and medium-sized enterprises in the field of agriculture, and thus get an insight into the current state of development of this sector of agriculture, as well as point out the possibilities for the future development of SMEs in agribusiness of Vojvodina.Agricultural production, Small and medium sized enterprises (SMEs), Clusters analysis, Clustering of communes in Vojvodina, Agribusiness, Community/Rural/Urban Development, Public Economics,

Cooperative Jahn-Teller Coupling in the Manganites

URL:http://link.aps.org/doi/10.1103/PhysRevLett.84.1603 DOI:10.1103/PhysRevLett.84.1603The cooperative Jahn-Teller coupling between the Mn eg electrons and the oxygen octahedral distortions in LaMnO3 is studied using ab initio density-functional calculations and tight-binding models. The linear and quadratic vibronic coupling parameters are calculated using density-functional methods. It is shown that the cooperative Jahn-Teller coupling, primarily due to the interoctahedral electron hopping (band structure term), leads to the ordering of the octahedral distortion and simultaneously to orbital ordering. The coupling results in a two-minima adiabatic potential surface in the solid, instead of the three-minima “Mexican-hat” surface for the isolated octahedron.We thank the Research Board of the University of Missouri for partial financial support

Quantitative estimations of foveal and extra-foveal retinal circuitry in humans

AbstractFor an understanding of the basis for psychophysical measurement of visual resolution, quantitative morphological studies of retinal neuronal architecture are needed. Here we report on cell densities and retinal ganglion cell:cone ratio (RGC:C) from the foveal border to the peripheral retina (34° eccentricity). Quantitative estimates of RGC and C densities were made using a modified disector method in three vertically sectioned human retinae and were adjusted for RGC displacement. In agreement with our previous data on humans, we found an RGC:C ratio close to 3 at 2–3° eccentricity. Outside the foveal border, the ratio declined to 1.0 at 7.5° eccentricity and to 0.5 at eccentricities larger than 19°. Center-to-center separation of C and RGC in addition to center-to-center separation of estimated ‘receptive fields’ was calculated at corresponding locations along the superior and inferior hemimeridians. The center-to-center separation of estimated ‘receptive fields’ was found to be more closely related to resolution thresholds from the fovea to 19° eccentricity than was the separation of RGC and C. On the basis of these quantitative estimates, models for neural circuitry involved in central and peripheral spatial vision can be discussed

Suggestions and recommendations for fulfillment and implementation of the project for Broadband internet in Macedonia

Nowadays, broadband is defined on the basis of a number of parameters that can be offered through existing electronic communications networks (fixed or mobile networks) and the construction of some next generation of advanced electronic communications networks. This is extremely important for the quality of the received service, because with the existence of a quality electronic communication network, you will distribute a quality and fast data transfer to the end users, some of whom actually want it. Optical cable, among other types of cables, using the Operator and the access method known as fiber to the home , has a very good advantage for the end user, who uses the required service. On the other hand, wireless technologies such as Wi-Fi, Wi-Max and GSM / GPRS / UMTS / HSDPA, 4G and 5G are also new ways to access the Internet. This electronic communication infrastructure owned by a Public Operator for Electronic Communications Services (eg optical network or wireless 4G or 5G network) would be able to provide to the users significantly higher speed and security in data transmission, consistency at speeds, reduced error rates of real-time applications (video streaming, video communication, etc.). This paper provides suggestions and recommendations for fulfilling and implementing the broadband projest. It clarifies in which segments corrections should be made in the regulatory acts, with legal and by the laws. The real situation in the part of the broadband internet in our state is summarized in which direction the goals for improvement and fulfillment of the functioning of the broadband internet should move in the future

Electronic structure and exchange interaction in the layered perovskite Sr3Mn2O7

URL:http://link.aps.org/doi/10.1103/PhysRevB.65.094402 DOI:10.1103/PhysRevB.65.094402The electronic structure of the Ruddlesden-Popper layered perovskite compound Sr3Mn2O7 is studied from density-functional calculations using the linear muffin-tin orbital method. An antiferromagnetic, insulating solution is obtained in agreement with the experiments, with a magnetic moment of about 2.52μB for each Mn atom. The magnetic interactions between the Mn atoms, both within the bilayer and between the bilayers, are shown to arise from superexchange. The intrabilayer interaction involves the three-site Mn-O-Mn superexchange much like the case of the well-known CaMnO3, while the interbilayer exchange, mediated via the longer Mn-O-O-Mn superexchange path, is considerably weaker. Consistent with the layered nature of the compound, we find a strong out-of-plane to in-plane band-mass anisotropy for Sr3Mn2O7(mz*/mx,y*∼10.9 for electrons and ∼4.2 for holes), while for the related compound LaSr3Mn2O7, which is a ferromagnetic metal, we obtain a strong anisotropy in the resistivity ρc/ρab∼40 using kinetic transport theory, in qualitative argument with the experimental value of ∼100.This work was supported by the U. S. Department of Energy under Contract No. DOE FG02-00E0045818

Density‐functional studies of the electronic structure of the perovskite oxides: La1−xCaxMnO3

doi:10.1063/1.361546Using density‐functional methods, we study the electronic structures of the lanthanum‐based ''double‐exchange'' perovskite magnets. Antiferromagnetic insulating solutions are obtained for both the end members, LaMnO3 and CaMnO3, within the local density approximation (LDA), with the Jahn‐Teller (JT) distortion of the oxygen octrahedron taken into account. The JT distortion splits off the Mn(3d)eg bands producing an energy gap within the LDA, with the bands derived from the (z2−1) orbital, pointed along the long basal‐plane Mn—O bond, occupied and the (x2−y2) bands empty. The on‐site Coulomb repulsion and the intra‐site exchange terms are found to be, respectively, U≂8-10 eV and J≂0.9 eV, from the ''constrained'' density‐functional theory. The large value of U as compared to the bandwidth indicates that the manganese perovskite oxides are strongly correlated systems.This work was supported in part by the Office of Naval Research under Contract No. ONR N00014-95-1-0439 and by the Serbian Scientific Foundation under the project, ''Physics of Condensed Matter and New Materials,'' Grant No. 3

Electronic Structure of the Perovskite Oxides: La1-xCaxMnO3

URL:http://link.aps.org/doi/10.1103/PhysRevLett.76.960 DOI:10.1103/PhysRevLett.76.960The electronic structures of the perovskite oxides, LaMnO3 and CaMnO3, are studied using density-functional methods. Antiferromagnetic insulating (AFI) solutions are obtained for both compounds within the local-density approximation (LDA). For LaMnO3 the Jahn-Teller distortion, found necessary for the AFI solution, produces occupied Mn(z2-1) orbitals pointed along the long, basal-plane Mn-O bonds. The large on-site Coulomb U and exchange J, obtained from “constrained” LDA calculations, U≈8-10eV and J≈0.9eV, indicate important correlation effects and yield large redistribution of the spectral weight within the LDA+U approach.We thank O. Gunnarsson for stimulating discussions. This work was supported in part by the Office of Naval Research under Contract No. ONR N00014-95-1-0439