Schwinger's oscillator method, supersymmetric quantum mechanics and massless particles

We consider the Schwinger's method of angular momentum addition using the SU(2) algebra with both a fermionic and a bosonic oscillator. We show that the total spin states obtained are: one boson singlet state and an arbitrary number of spin-1/2 states, the later ones are energy degenerate. It means that we have in this case supersymmetric quantum mechanics and also the addition of angular momentum for massless particles. We review too the cases of two bosonic and fermionic oscillators.Comment: 11 pages,RevTe

Gainsharing: A Critical Review and a Future Research Agenda

This paper provides a critical review of the extensive literature on gainsharing. It examines the reasons for the fast growth in these programs in recent years and the major prototypes used in the past. Different theoretical formulations making predictions about the behavioral consequences and conditions mediating the success of these programs are discussed and the supporting empirical evidence is examined. The large number of a theoretical case studies and practitioner reports or gainsharing are also summarized and integrated. The article concludes with a suggested research agenda for the future

Do CEOs Ever Lose? Fairness Perspective on the Allocation of Residuals Between CEOs and Shareholders

In this study we introduce a justice perspective to examining the result of bargaining between CEOs and boards over the allocation of firm residuals that ultimately determines CEO compensation. Framing CEO pay as the result of bargaining between CEOs and boards focuses attention on the power of CEOs to increase their share of firm residuals in the form of increased compensation, and the diligence of boards of directors to constrain CEO opportunism. Framing this negotiation through a theory of justice offers an alternative perspective to the search for pay-performance sensitivity. We predict and find that as board diligence in controlling opportunism declines and CEO power increases, CEOs are increasingly able to capture a larger portion of firm residuals relative to shareholders. This finding supports critics who charge that CEO pay violates norms of distributive and procedural justice

Gainsharing and Mutual Monitoring: A Combined Agency-Procedural Justice Interpretation

This study examines the behavioral consequences of gainsharing using a combined theoretical framework that includes elements of agency and procedural justice theory. The hypothesis tested is that gainsharing as a collective form of incentive alignment results in increased mutual monitoring among agents (employees) when the plan is perceived to be procedurally fair. The hypothesis was supported in two separate firms using a quasi-experimental field study. The implications of the study for future extensions of agency theory to examine intraorganizational phenomena are discussed

Improvement and analysis of a pseudo random bit generator by means of cellular automata

In this paper, we implement a revised pseudo random bit generator based on a rule-90 cellular automaton. For this purpose, we introduce a sequence matrix H_N with the aim of calculating the pseudo random sequences of N bits employing the algorithm related to the automaton backward evolution. In addition, a multifractal structure of the matrix H_N is revealed and quantified according to the multifractal formalism. The latter analysis could help to disentangle what kind of automaton rule is used in the randomization process and therefore it could be useful in cryptanalysis. Moreover, the conditions are found under which this pseudo random generator passes all the statistical tests provided by the National Institute of Standards and Technology (NIST)Comment: 20 pages, 12 figure

Quantum and classical echoes in scattering systems described by simple Smale horseshoes

We explore the quantum scattering of systems classically described by binary and other low order Smale horseshoes, in a stage of development where the stable island associated with the inner periodic orbit is large, but chaos around this island is well developed. For short incoming pulses we find periodic echoes modulating an exponential decay over many periods. The period is directly related to the development stage of the horseshoe. We exemplify our studies with a one-dimensional system periodically kicked in time and we mention possible experiments.Comment: 7 pages with 6 reduced quality figures! Please contact the authors ([email protected]) for an original good quality pre-prin

Strain and order-parameter coupling in Ni-Mn-Ga Heusler alloys from resonant ultrasound spectroscopy

Resonant ultrasound spectroscopy and magnetic susceptibility experiments have been used to characterize strain coupling phenomena associated with structural and magnetic properties of the shape-memory Heusler alloy series Ni$_{50+x}$Mn$_{25-x}$Ga$_{25}$ ($x=0$, 2.5, 5.0, and 7.5). All samples exhibit a martensitic transformation at temperature $T_M$ and ferromagnetic ordering at temperature $T_C$, while the pure end member ($x=0$) also has a premartensitic transition at $T_{PM}$, giving four different scenarios: $T_C>T_{PM}>T_M$, $T_C>T_M$ without premartensitic transition, $T_C\approx T_M$, and $T_C<T_M$. Fundamental differences in elastic properties i.e., stiffening versus softening, are explained in terms of coupling of shear strains with three discrete order parameters relating to magnetic ordering, a soft mode and the electronic instability responsible for the large strains typical of martensitic transitions. Linear-quadratic or biquadratic coupling between these order parameters, either directly or indirectly via the common strains, is then used to explain the stabilities of the different structures. Acoustic losses are attributed to critical slowing down at the premartensite transition, to the mobility of interphases between coexisting phases at the martensitic transition and to mobility of some aspect of the twin walls under applied stress down to the lowest temperatures at which measurements were made.Comment: 9 pages, 5 figure

Pilot study of vegetation in the Alchichica-Perote region by remote sensing

A study of the application of satellite images to the identification of vegetation in a small area corresponding to the arid zone of Veracruz and part of Puebla is presented. This study is accomplished by means of images from the LANDSAT satellite obtained on January 19 and May 23, 1973. The interpretation of the different maps is made on the basis of information from the data bank of the Flora de Veracruz program, and various surveys made by land and air

Local Economic Development Program Planning: An Evaluation Toolkit for the South Valley Economic Development Center

Entering its sixth year of operation, the South Valley Economic Development Center (SVEDC) has served over 900 entrepreneurs in various capacities, such as environmental health trainings, providing low-cost rental space, and offering guidance on business development. Established to meet the economic needs of the South Valley of Bernalillo County, New Mexico, the SVEDC originated out of community organizing efforts around economic development, land use, and infrastructure planning. Through these original efforts, the Rio Grande Community Development Corporation (RGCDC), with the help of other local groups, assessed the local economic needs and determined that business incubation program was the appropriate response to those needs. In addition to coming up with the idea, the RGCDC and other groups successfully lobbied for local government support for the program and raised significant funds to finance the construction of a building to house the program. After these first five years, it seems an appropriate time to evaluate the programs progress so far in accomplishing its goals. Therefore, the principal contribution of this project was to create an evaluation framework for RGCDC for use in ongoing program evaluation. More specifically, to contribute to internal evaluation and planning, the defining purposes of this project were to: (1) Develop an incubator-wide evaluation framework to be used by the RGCDC to assess the SVEDC\u27s development. (2) Implement early stages of the evaluation framework to lay the groundwork for future ongoing data collection and evaluation. (3) Provide process recommendations based on the findings of the initial evaluation. (4) Present next steps for how to use this document for future program evaluations. In order to develop and implement the evaluation framework, the evaluator consulted with different SVEDC stakeholders, including original founding members of the center, current staff and administration, current program participants, and former program participants

Mathematical hybrid models for image segmentation.

Two hybrid image segmentation models that are able to process a wide variety of images are proposed. The models take advantage of global (region) and local (edge) data of the image to be segmented. The first one is a region-based PDE model that incorporates a combination of global and local statistics. The influence of each statistic is controlled using weights obtained via an asymptotically stable exponential function. Through incorporation of edge information, the second model extends the capabilities of a strictly region-based variational formulation, making it able to process more general images. Several examples are provided showing the improvements of the proposed models over recent methods along with an application to dermoscopy imaging. A number of avenues for future research are also discussed