Agrarian structure in Poland : the myth of large-farm superiority

In Poland, present policies are aimed at promoting large, mechanized farms over smaller family farms. These policies are based on the perception that large farms offer real economies of scale. But international evidence indicates that such large, mechanized farms are generally less efficient and use less labor than small family farms. The authors analyzed the relationship between farm size and efficiency in Polish agriculture. They used two different methods to do so. First they determined differences in total factor productivity between small and large farms. They then used Data Envelope Analysis to estimate scale efficiencies. The results show that, for the sample of farms analyzed: 1) large farms are not more efficient than smaller farms; and 2) smaller farms are more labor-intensive than larger farms. These results have important policy implications for farm restructuring in Poland and other transition economies facing similar issues and conditions.Environmental Economics&Policies,Crops&Crop Management Systems,Agricultural Knowledge&Information Systems,Banks&Banking Reform,Economic Theory&Research,Banks&Banking Reform,Environmental Economics&Policies,Agricultural Knowledge&Information Systems,Crops&Crop Management Systems,Livestock&Animal Husbandry

Parallelized multi-degrees-of-freedom cell mapping method

Long-term global analysis of lower-dimensional systems can be performed by in a computationally efficient manner by using cell mapping methods. Scaling limitations associated with higher order systems can be addressed by using the multiple degree-of-freedom cell mapping (MDCM) method. However, the MDCM algorithm consists of a number of sequential operations which limits its ability to utilize the parallel processing capabilities of modern computers. A parallelized multiple degree-of-freedom cell mapping (PMDCM) method is introduced here to address this limitation. By restructuring the MDCM algorithm to enable parallel operations, the efficiency of the algorithm is significantly enhanced. The details of the PMDCM algorithm are presented and performance is compared to the MDCM method and baseline obtained by using the grid-of-starts method. By running the PMDCM method on a workstation with a quad-core processor and by parallelizing 100 numerical integration operations, the total computation time is decreased by 93% from the time required of the MDCM method. Parallelizing the integration operations also reduces the error which can accumulate when by using the sequential operations of the MDCM method

Diffraction gratings in caligoid (Crustacea: Copepoda) ecto- parasites of large fishes

Three previously unreported examples of animal diffraction gratings are described, in Gloiopotes huttoni, Dinemoura latifolia and Dinematura braccata (Copepoda: Calligoida), crustacean parasites of large marlins (Istiophoridae) and sharks (Selachimorpha). The gratings occur on the marginal membrane which fringes the carapace. The gratings of G. huttoni are more efficient, optically, than those of D. latifolia and D. braccata; the strong iridescence of G. huttoni may function as an aggregation cue for the copepods on their host fishes, while the gratings of the other species may be a by-product of a structure with optimal properties related to strength. Additionally, G. huttoni possess chromatophores to produce camouflage and maintains camouflage in the ultraviolet-A wavelengths

Chromosomal diversification and karyotype evolution of diploids in the cytologically diverse genus Prospero (Hyacinthaceae)

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited

Budd-Chiari syndrome recurring in a transplanted liver

A patient with Budd-Chiari syndrome who underwent orthotopic liver transplantation and developed recurrent disease is described. The immediate postoperative period was complicated by multiple thrombotic episodes, followed by a period of apparent remission associated with the initiation of coumadin and persantine therapy. After discontinuation of such antithrombotic therapy in order to biopsy the liver, the patient experienced another series of clinically overt vascular thromboses and ultimately died of sepsis 15 mo posttransplantation after a prolonged and complicated terminal hospital course. At autopsy, recurrent Budd-Chiari syndrome as well as thromboses in numerous other organs was demonstrated. © 1983

Stellar Explosions by Magnetic Towers

We propose a magnetic mechanism for the collimated explosion of a massive star relevant for GRBs, XRFs and asymmetric supernovae. We apply Lynden-Bell's magnetic tower scenario to the interior of a massive rotating star after the core has collapsed to form a black hole with an accretion disk or a millisecond magnetar acting as a central engine. We solve the force-free Grad-Shafranov equation to calculate the magnetic structure and growth of a tower embedded in a stellar environment. The pressure of the toroidal magnetic field, continuously generated by differential rotation of the central engine, drives a rapid expansion which becomes vertically collimated after lateral force balance with the surrounding gas pressure is reached. The collimation naturally occurs because hoop stress concentrates magnetic field toward the rotation axis and inhibits lateral expansion. This leads to the growth of a self-collimated magnetic tower. When embedded in a massive star, the supersonic expansion of the tower drives a strong bow shock behind which an over-pressured cocoon forms. The cocoon confines the tower by supplying collimating pressure and provides stabilization against disruption due to MHD instabilities. Because the tower consists of closed field lines starting and ending on the central engine, mixing of baryons from the cocoon into the tower is suppressed. The channel cleared by the growing tower is thus plausibly free of baryons and allows the escape of magnetic energy from the central engine through the star. While propagating down the stellar density gradient, the tower accelerates and becomes relativistic. During the expansion, fast collisionless reconnection becomes possible resulting in dissipation of magnetic energy which may be responsible for GRB prompt emission.Comment: 19 pages, 8 figures, accepted to ApJ, updated references and additional discussion adde

Spin reorientation in TlFe1.6Se2 with complete vacancy ordering

The relationship between vacancy ordering and magnetism in TlFe1.6Se2 has been investigated via single crystal neutron diffraction, nuclear forward scattering, and transmission electron microscopy. The examination of chemically and structurally homogenous crystals allows the true ground state to be revealed, which is characterized by Fe moments lying in the ab-plane below 100K. This is in sharp contrast to crystals containing regions of order and disorder, where a competition between c-axis and ab-plane orientations of the moments is observed. The properties of partially-disordered TlFe1.6Se2 are therefore not associated with solely the ordered or disordered regions. This contrasts the viewpoint that phase separation results in independent physical properties in intercalated iron selenides, suggesting a coupling between ordered and disordered regions may play an important role in the superconducting analogues.Comment: Minor changes; updated references and funding acknowledgemen

Popular critiques of consultancy and a politics of management learning?

In this short article, I argue that popular business discourse on the role of management consultancy in the promotion and translation of management ideas is often critical, informed by more or less implicit ethical and political concerns with employee security, equity, openness and the transparency and legitimacy of responsibility. These concerns are, in part, ‘sayable’ because their object is seen as a scapegoat for management. Nevertheless, combined with the popular form of their expression, they can support and legitimize critical studies of management learning, a discipline which otherwise has become overly concerned with processual and situational phenomena at the expense of broader political dynamics and of the content and consequences of management and management knowledg