Comment on "Relativistic extension of shape-invariant potentials"

This comment directs attention to some fails of the Alhaidari approach to solve relativistic problems. It is shown that his gauge considerations are way off the mark and that the class of exactly solvable relativistic problems is not so enlarged as Alhaidari thinks it is

THE CHANGING INFORMATION NEEDS OF FARMERS IN THE U.S. AND EUROPE

Both policy and market forces are causing unprecedented changes in agricultural structure and management in both the United States and in Europe. These changes will have profound impacts on the role of universities and extension services who provide information and education to farmers. This paper discusses some of the emerging and anticipated changes in information content and delivery in both the US and the EU. Some of the primary issues US agricultural producers will need to address as a result of the changes in the agricultural industry and policy include: strategic positioning, transferring management capabilities, frequent performance monitoring, evaluating new technology, monitoring external factors, managing information, and accountability. The information needs of farmers in Europe are closely linked to the evolution of the Common Agricultural Policy (CAP) of the European Union. The general agricultural policy framework is briefly presented in the paper. Price reduction, agri-environmental measures enhancement, and rural development policy are the most important elements of CAP reform. European agriculture is in the midst of major changes, mostly started in 1992, but destined to continue and increase in the near future. Different approaches to manage the agricultural sector involve the need for a different information system for farmers. It means not only new content in information, but also new ways to inform and do technical assistance. The primary information needs out are: farm management, risk management, EU programs and measures, quality production, low input and organic farming, marketing and advertising management, new technology introduction, structural adjustment funds management, investment decisions, rural tourism and recreational activities management. European agriculture is on the path to large and challenging changes. There is no way for farmers alone to manage these changes, and remain competitive in the market. Providing information has become the most important part of the extension activity. Information must include training sessions, demonstrations in the field, and assessment, together with the farmers, of the activities and the results obtained. There are many similarities in the farm management information needs of farmers in the US and EU. A critical factor for the Extension Services in the future is to adjust rapidly to the changes, and quickly develop new content and delivery plans for farmers' training. The challenge for universities and extension services to respond to the information needs will strain their resources. Collaborative efforts between our institutions may prove more valuable as faculty attempt to develop research and educational programs relevant to the emerging information needs. In addition, cooperation with the growing private sector agricultural education programs will probably be essential if public education and information delivery systems are to remain relevant.Farm Management,

The peremptory influence of a uniform background for trapping neutral fermions with an inversely linear potential

The problem of neutral fermions subject to an inversely linear potential is revisited. It is shown that an infinite set of bound-state solutions can be found on the condition that the fermion is embedded in an additional uniform background potential. An apparent paradox concerning the uncertainty principle is solved by introducing the concept of effective Compton wavelength

Thermodynamics of nano-spheres encapsulated in virus capsids

We investigate the thermodynamics of complexation of functionalized charged nano-spheres with viral proteins. The physics of this problem is governed by electrostatic interaction between the proteins and the nano-sphere cores (screened by salt ions), but also by configurational degrees of freedom of the charged protein N-tails. We approach the problem by constructing an appropriate complexation free energy functional. On the basis of both numerical and analytical studies of this functional we construct the phase diagram for the assembly which contains the information on the assembled structures that appear in the thermodynamical equilibrium, depending on the size and surface charge density of the nano-sphere cores. We show that both the nano-sphere core charge as well as its radius determine the size of the capsid that forms around the core.Comment: Submitte

Collective behavior of heterogeneous neural networks

We investigate a network of integrate-and-fire neurons characterized by a distribution of spiking frequencies. Upon increasing the coupling strength, the model exhibits a transition from an asynchronous regime to a nontrivial collective behavior. At variance with the Kuramoto model, (i) the macroscopic dynamics is irregular even in the thermodynamic limit, and (ii) the microscopic (single-neuron) evolution is linearly stable.Comment: 4 pages, 5 figure

The Dark Sequential Z' Portal: Collider and Direct Detection Experiments

We revisit the status of a Majorana fermion as a dark matter candidate when a sequential Z' gauge boson dictates the dark matter phenomenology. Direct dark matter detection signatures rise from dark matter-nucleus scatterings at bubble chamber and liquid xenon detectors, and from the flux of neutrinos from the Sun measured by the IceCube experiment, which is governed by the spin-dependent dark matter-nucleus scattering. On the collider side, LHC searches for dilepton and mono-jet + missing energy signals play an important role. The relic density and perturbativity requirements are also addressed. By exploiting the dark matter complementarity we outline the region of parameter space where one can successfully have a Majorana dark matter particle in light of current and planned experimental sensitivities.Comment: 22 pages, 6 figure

Entropy potential and Lyapunov exponents

According to a previous conjecture, spatial and temporal Lyapunov exponents of chaotic extended systems can be obtained from derivatives of a suitable function: the entropy potential. The validity and the consequences of this hypothesis are explored in detail. The numerical investigation of a continuous-time model provides a further confirmation to the existence of the entropy potential. Furthermore, it is shown that the knowledge of the entropy potential allows determining also Lyapunov spectra in general reference frames where the time-like and space-like axes point along generic directions in the space-time plane. Finally, the existence of an entropy potential implies that the integrated density of positive exponents (Kolmogorov-Sinai entropy) is independent of the chosen reference frame.Comment: 20 pages, latex, 8 figures, submitted to CHAO

Cosmological perturbations of a perfect fluid and noncommutative variables

We describe the linear cosmological perturbations of a perfect fluid at the level of an action, providing thus an alternative to the standard approach based only on the equations of motion. This action is suited not only to perfect fluids with a barotropic equation of state, but also to those for which the pressure depends on two thermodynamical variables. By quantizing the system we find that (1) some perturbation fields exhibit a noncommutativity quite analogous to the one observed for a charged particle moving in a strong magnetic field, (2) local curvature and pressure perturbations cannot be measured simultaneously, (3) ghosts appear if the null energy condition is violated.Comment: 4 pages, uses RevTeX. Title modified, references and comments added