Supernova Relic Electron Neutrinos and anti-Neutrinos in future Large-scale Observatories

We investigate the signal from supernova relic neutrinos in future large scale observatories, such as MEMPHYS (UNO, Hyper-K), LENA and GLACIER, at present under study. We discuss that complementary information might be gained from the observation of supernova relic electron anti-neutrinos and neutrinos using the scattering on protons on one hand, and on nuclei such as oxygen, carbon or argon on the other hand. When determining the relic neutrino fluxes we also include, for the first time, the coupling of the neutrino magnetic moment to magnetic fields within the core-collapse supernova. We present numerical results on both the relic electron neutrino and anti-neutrino fluxes and on the number of events for electron neutrinos on carbon, oxygen and argon, as well as electron anti-neutrinos on protons, for various oscillation scenarios. The observation of supernova relic neutrinos might provide us with unique information on core-collapse supernova explosions, on the star formation history and on neutrino properties, that still remain unknown.Comment: 15 pages, 13 figures, 7 table

Short versus long range interactions and the size of two-body weakly bound objects

Very weakly bound systems may manifest intriguing "universal" properties, independent of the specific interaction which keeps the system bound. An interesting example is given by relations between the size of the system and the separation energy, or scaling laws. So far, scaling laws have been investigated for short-range and long-range (repulsive) potentials. We report here on scaling laws for weakly bound two-body systems valid for a larger class of potentials, i.e. short-range potentials having a repulsive core and long-range attractive potentials. We emphasize analogies and differences between the short- and the long-range case. In particular, we show that the emergence of halos is a threshold phenomenon which can arise when the system is bound not only by short-range interactions but also by long-range ones, and this for any value of the orbital angular momentum $\ell$. These results enlarge the image of halo systems we are accustomed to.Comment: 6 pages, 1 figure. To be published in the Proceedings of the Workshop "Hirschegg 2003: Nuclear Structure and Dynamics at the Limits", Hirschegg, January 12 - 18, 200

Description of Heavy Quark Systems by means of Energy Dependent Potentials

We apply, for the first time, an energy dependent Schrodinger equation to describe static properties of heavy quark systems, i.e. charmonium and bottonium. We show that a good description of the eigenstates and reasonable values for the widths can be obtained. Values of the radii and of the density at the origin are also given. We compare the results to those deduced with a Schrodinger equation implemented with potentials used so far. We note that the energy dependence of the confining potential provides a natural mechanism for the saturation of the spectra. Our results introduce a new class of potentials for the description of heavy quark systems.Comment: 3 page

Exploring the Potential Effects of Organic Production on Contracting in American Agribusiness

Organic production, while still a niche market in U.S. agriculture, is growing at a rapid rate. This paper argues that organic producers, particularly those seeking certification to sell at the retail level, share many characteristics with conventional producers who opt for contracting over independence. These include yield risk, search and transaction costs, and technological changes. Depending on the rate at which federal assistance programs grow and evolve to serve organic producers, contracting may become a popular choice within the organic sector. In turn, contracting may come to cover a significantly larger share of agricultural production as the organic sector continues to grow.Agribusiness,

Supermarket Competition through Price Promotions: A Cross Category Analysis

This study takes an important first step at quantifying the nature of competition between major supermarket chains through price promotions. Using data that covers virtually the entire product menus of supermarkets representing two major chains in 18 cities, I examine both the effect of direct competition on promotional intensity and the nature of promotional competition itself. In a counterintuitive finding, there appears to slightly less promotional activity in cities in which both chains compete directly, as compared to cities in which only one chain operates. Moreover, most promotional activity tends to be retaliatory, rather than accommodating, in nature. This study takes an important first step at quantifying the nature of competition between major supermarket chains through price promotions. Using data that covers virtually the entire product menus of supermarkets representing two major chains in 18 cities, I examine both the effect of direct competition on promotional intensity and the nature of promotional competition itself. In a counterintuitive finding, there appears to slightly less promotional activity in cities in which both chains compete directly, as compared to cities in which only one chain operates. Moreover, most promotional activity tends to be retaliatory, rather than accommodating, in nature.Agribusiness, Demand and Price Analysis,

National Brand and Private Label Pricing and Promotional Strategy

In this paper I use a unique and rich data set on prices and promotions from major US supermarkets to examine the nature of National Brand and Private Label interaction. Private labels are priced and promoted competitively with NBs, in a manner suggesting that retails are careful not to lose private label market share during times of national brand promotions. The price margin between the two types of products continues to fall in US supermarkets, and the major determinants of the price differences between the two are promotional frequency and market concentration.food retail, industrial organization, food prices, promotional activity, Agribusiness, Demand and Price Analysis, Industrial Organization, Marketing,

Singular point characterization in microscopic flows

We suggest an approach to microrheology based on optical traps in order to measure fluid fluxes around singular points of fluid flows. We experimentally demonstrate this technique, applying it to the characterization of controlled flows produced by a set of birefringent spheres spinning due to the transfer of light angular momentum. Unlike the previous techniques, this method is able to distinguish between a singular point in a complex flow and the absence of flow at all; furthermore it permits us to characterize the stability of the singular point.Comment: 4 pages and 4 figure

Possible CP-Violation effects in core-collapse Supernovae

We study CP-violation effects when neutrinos are present in dense matter, such as outside the proto-neutron star formed in a core-collapse supernova. Using general arguments based on the Standard Model, we confirm that there are no CP-violating effects at the tree level on the electron neutrino and anti-neutrino fluxes in a core-collapse supernova. On the other hand significant effects can be obtained for muon and tau neutrinos even at the tree level. We show that CP violating effects can be present in the supernova electron (anti)neutrino fluxes as well, if muon and tau neutrinos have different fluxes at the neutrinosphere. Such differences could arise due to physics beyond the Standard Model, such as the presence of flavor-changing interactions.Comment: 11 pages, 18 figure

Brownian motion in a non-homogeneous force field and photonic force microscope

The Photonic Force Microscope (PFM) is an opto-mechanical technique based on an optical trap that can be assumed to probe forces in microscopic systems. This technique has been used to measure forces in the range of pico- and femto-Newton, assessing the mechanical properties of biomolecules as well as of other microscopic systems. For a correct use of the PFM, the force field to measure has to be invariable (homogeneous) on the scale of the Brownian motion of the trapped probe. This condition implicates that the force field must be conservative, excluding the possibility of a rotational component. However, there are cases where these assumptions are not fulfilled Here, we show how to improve the PFM technique in order to be able to deal with these cases. We introduce the theory of this enhanced PFM and we propose a concrete analysis workflow to reconstruct the force field from the experimental time-series of the probe position. Furthermore, we experimentally verify some particularly important cases, namely the case of a conservative or rotational force-field

The Effect of Wal-Mart Supercenters on Grocery Prices in New England

This study analyzes the effect of the presence of Wal-Mart Supercenters on the prices at conventional supermarkets in Massachusetts, Connecticut, and Rhode Island. Using price indexes constructed from primary price data on a basket of 54 goods and holding several demographics and market conditions constant, we determine that Supercenters result in a 7.79% average price reduction in national brand goods and a 6.38% average price reduction in private label goods. Wal-Mart Supercenters also price their groceries on average 15.65% lower than supermarkets competing with Supercenters and 22.28% lower than supermarkets geographically distant from Supercenters.Marketing,