The Casimir effect for thin plasma sheets and the role of the surface plasmons

We consider the Casimir force betweeen two dielectric bodies described by the plasma model and between two infinitely thin plasma sheets. In both cases in addition to the photon modes surface plasmons are present in the spectrum of the electromagnetic field. We investigate the contribution of both types of modes to the Casimir force and confirm resp. find in both models large compensations between the plasmon modes themselves and between them and the photon modes especially at large distances. Our conclusion is that the separation of the vacuum energy into plasmon and photon contributions must be handled with care except for the case of small separations.Comment: submitted to JPhysA Special Issue QFEXT'05, replaced due to a wrong Latex comman

A Comparison of Traditional and Newly Emerging Forms of Cooperative Capitalization

This paper compares the traditional forms of capitalization used by American co-ops to newly emerging forms. It is based on an in-depth review of several case co-ops. A broad framework is provided that may be beneficial in more extensive studies of capitalization practices of cooperatives and similar organizations. It is divided into three parts. Part One outlines the alternative capitalization forms being used by cooperatives and their antecedents, where conversions to other structures and forms have occurred. Two basic capitalization forms have been used by cooperatives: traditional (open) and new generation (closed). Cooperatives using both forms have elected to add new capitalization features, such as use of publicly listed stock, or have elected to convert to different forms, such as an LLC or a C corporation. Several perceived advantages have motivated these changes besides the traditional advantages utilized by cooperative corporations, limited liability and single taxation. They include access to capital, liquidity and appreciability of stock. Part Two provides a brief description of the nature and experience of several modern cooperative organizations using the framework presented in Part One. The descriptions are based on in-depth case studies. The case study selections are from a broad cross-section of cooperatives that include the following: (1) Mid-Kansas Cooperative (traditional, centralized, local grain marketing and farm supply using only internally generated equity); (2) Land O'Lakes (traditional, centralized and federated, regional dairy marketing and processing and farm supply using only internally generated equity and registered debt financing); (3) CHS Cooperatives (traditional, primarily federated, regional grain marketing and processing and farm supply, with the recent addition of publicly listed preferred stock); and (4) U.S. Premium Beef (new generation, centralized, regional beef processing using closely held but tradeable common stock and proposal to convert to an LLC with member and non-member tradeable stock). In addition brief mention is made of other cooperatives including (5) Dakota Growers Pasta (new generation, centralized, regional durum wheat processing with recent conversion to C corporation); (6) South Dakota Soybean Processing (new generation, centralized regional soybean processing with conversion to LLC); (7) Pro-Fac and Birds Eye Foods (new generation centralized regional frozen vegetable processing with publicly listed stock and transition of processing entity, Birds Eye, to majority ownership by investor-oriented partner likely to exit through an IPO) and (8) Gold Kist (traditional, centralized regional poultry processing with proposed conversion to publicly traded C corporation). Part Three will briefly outline some of the challenges facing cooperatives in the future with reference to capitalization.Financial Economics, Agribusiness,

Fluctuations of the Casimir-Polder force between an atom and a conducting wall

We consider the quantum fluctuations of the Casimir-Polder force between a neutral atom and a perfectly conducting wall in the ground state of the system. In order to obtain the atom-wall force fluctuation we first define an operator directly associated to the force experienced by the atom considered as a polarizable body in an electromagnetic field, and we use a time-averaged force operator in order to avoid ultraviolet divergences appearing in the fluctuation of the force. This time-averaged force operator takes into account that any measurement involves a finite time. We also calculate the Casimir-Polder force fluctuation for an atom between two conducting walls. Experimental observability of these Casimir-Polder force fluctuations is also discussed, as well as the dependence of the relative force fluctuation on the duration of the measurement.Comment: 6 page

Contributions of Vacuum and Plasmon Modes to the Force on a Small Sphere near a Plate

The force on a small sphere with a plasma model dielectric function and in the presence of a perfectly reflecting plane is considered. The contribution of both the vacuum modes of the quantized electromagnetic field and of plasmon modes in the sphere are discussed. In the case that the plasmon modes are in their ground state, quasi-oscillatory terms from the vacuum and plasmon parts cancel one another, leading a monotonic attractive force. If the plasmon modes are not in the ground state, the net force is quasi-oscillatory. In both cases, the sphere behaves in the same way as does an atom in either its ground state or an excited state.Comment: 7 pages, no figures, talk presented at "Quantum Fields under External Conditions - 2005", Barcelona, Spain, September 200

Reducing Reoffending: Review of Selected Countries: Final Review for Audit Scotland

The report reviews reoffending patterns in Scotland, England and Wales, Ireland, Northern Ireland, Norway and New Zealand to establish relevant conditions for different rates of reoffending. A significant part of the report, however, is given over to a critical examination of the concept of 'reoffending' itself which is more a measure of criminal justice agency behaviour than individual behaviour. The report concludes with some suggestions for moving beyond such thin, technocratic understanding of reoffending and rehabilitation. This work was commissioned by and submitted to Audit Scotland

Transfer of molybdenum disulfide to various metals

Sliding friction experiments were conducted with molybdenum disulfide single crystals in contact with sputter cleaned surfaces of copper, nickel, gold, and 304 stainless steel. Transfer of the molybdenum disulfide to the metals was monitored with Auger electron spectroscopy. Results of the investigation indicate molybdenum disulfide transfers to all clean metal surfaces after a single pass over the metal surface with film thickness observed to increase with repeated passes over the same surfaces. Large particle transfer occurs when the orientation of the crystallites is other than basal. This is frequently accompanied by abrasion of the metal. Adhesion of molybdenum disulfide films occurred readily to copper and nickel, less readily to 304 stainless steel, and even less effectively to the gold, which indicates a chemical effect

FCStone Conversion to a Public Corporation

FCStone Group (FCS) is a publicly held corporation that converted from a cooperative to a private corporation in 2005, and then converted to a public corporation in 2007. It is an integrated commodity risk management company that provides risk management consulting and transaction execution services to commercial commodity intermediaries, end users, and producers. This case study focuses primarily on the period from the first conversion in 2005 to six months after the public offering in March 2007. Because the financial benefits received by each of the cooperative owners of FCS are dependent on the timing of their sale of FCS stock, stock price information and benefit estimates are provided up to early November 2008.Agribusiness,

Diffraction in time: An exactly solvable model

In recent years, matter-wave interferometry has attracted growing attention due to its unique suitability for high-precision measurements and the study of fundamental aspects of quantum theory. Diffraction and interference of matter waves can be observed not only at a spatial aperture (such as a screen edge, slit, or grating), but also at a time-domain aperture (such as an absorbing barrier, or “shutter,” that is being periodically switched on and off). The wave phenomenon of the latter type is commonly referred to as “diffraction in time.” Here, we introduce a versatile, exactly solvable model of diffraction in time. It describes time evolution of an arbitrary initial quantum state in the presence of a time-dependent absorbing barrier, governed by an arbitrary aperture function. Our results enable a quantitative description of diffraction and interference patterns in a large variety of setups, and may be used to devise new diffraction and interference experiments with atoms and molecules

Nucleon-Nucleon Interactions from Dispersion Relations: Coupled Partial Waves

We consider nucleon-nucleon interactions from chiral effective field theory applying the N/D method. The case of coupled partial waves is now treated, extending Ref. [1] where the uncoupled case was studied. As a result three N/D elastic-like equations have to be solved for every set of three independent partial waves coupled. As in the previous reference the input for this method is the discontinuity along the left-hand cut of the nucleon-nucleon partial wave amplitudes. It can be calculated perturbatively in chiral perturbation theory because it involves only irreducible two-nucleon intermediate states. We apply here our method to the leading order result consisting of one-pion exchange as the source for the discontinuity along the left-hand cut. The linear integral equations for the N/D method must be solved in the presence of L - 1 constraints, with L the orbital angular momentum, in order to satisfy the proper threshold behavior for L>= 2. We dedicate special attention to satisfy the requirements of unitarity in coupled channels. We also focus on the specific issue of the deuteron pole position in the 3S1-3D1 scattering. Our final amplitudes are based on dispersion relations and chiral effective field theory, being independent of any explicit regulator. They are amenable to a systematic improvement order by order in the chiral expansion.Comment: 11 pages. Extends the work of uncoupled partial waves of M. Albaladejo and J. A. Oller, Phys. Rev. C 84, 054009 (2011) to the case of coupled partial waves. This version matches the published version. Discussion about the deuteron enlarged. Some references adde

Playing the Goblin Post Office game improves movement control of the core: a case study

Movement function of the core (trunk and pelvis) can be improved in cerebral palsy, potentially leading to benefits which transfer to activities of daily living. A single child with CP diplegia played our custom made game which runs on the CAREN system. Three playing postures gradually introduced more and more joints in the legs to be controlled. Vicon cameras tracked trunk and pelvic rotations which drove a dragon towards envelope targets. Forward speed of the game was adjusted by an adaptive algorithm leading to a maximum settled speed for the various conditions. Results showed that core control improved after the six week training period. The trunk was better controlled than the pelvis, sideways rotations were better controlled than fore-aft rotations of body segments, and single plane rotations were more efficient than cross-plane rotations of the core. The quantifiable improvements suggest a good potential for our technique to improve core control which is a prerequisite for good movement control of the legs and arms