CONDITIONAL DEMAND AND ENDOGENEITY? A CASE STUDY OF DEMAND FOR JUICE PRODUCTS

The question of endogeneity of conditional expenditures, as well as prices, in conditional demand equations for justices is examined. Both conditional expenditures and prices were found to be uncorrelated with the conditional demand errors, based on Wu-Hausman tests. Conditional demand error variance/covariance estimates and corresponding Slutsky coefficient estimates were approximately proportional, as predicted by the theory of rational random behavior, further supporting independence of conditional expenditures and conditional errors for juice demands.Demand and Price Analysis,

Advertising and Product Confusion: A Case Study of Grapefruit Juice

Demand relationships for two closely related products -- grapefruit juice and grapefruit-juice cocktail -- were estimated from grocery-store scanner data to analyze the contention that consumer confusion exists between the two products. Results suggest confusion may exist, with grapefruit-juice advertising not only increasing the demand for grapefruit juice but also for grapefruit-juice cocktail.advertising, demand, grapefruit juice, cocktail, scanner data, Agribusiness, Consumer/Household Economics, Demand and Price Analysis,

Perfect many-to-one teleportation with stabilizer states

We study the possibility of performing perfect teleportation of unknown quantum states from multiple senders to a single receiver with a previously shared stabilizer state. In the model we considered, the utilized stabilizer state is partitioned into several subsystems and then each subsystem is distributed to a distinct party. We present two sufficient conditions for a stabilizer state to achieve a given nonzero teleportation capacity with respect to a given partition plan. The corresponding teleportation protocols are also explicitly given. Interestingly, we find that even mixed stabilizer states are also useful for perfect many-to-one teleportation. Finally, our work provides a perspective from stabilizer formalism to view the standard teleportation protocol and also suggests a technique for analyzing teleportation capability of multipartite entangled states. © 2008 The American Physical Society

Phase Stability in the Two dimensional Anisotropic Boson Hubbard Hamiltonian

The two dimensional square lattice hard-core boson Hubbard model with near neighbor interactions has a `checkerboard' charge density wave insulating phase at half-filling and sufficiently large intersite repulsion. When doped, rather than forming a supersolid phase in which long range charge density wave correlations coexist with a condensation of superfluid defects, the system instead phase separates. However, it is known that there are other lattice geometries and interaction patterns for which such coexistence takes place. In this paper we explore the possibility that anisotropic hopping or anisotropic near neighbor repulsion might similarly stabilize the square lattice supersolid. By considering the charge density wave structure factor and superfluid density for different ratios of interaction strength and hybridization in the $\hat x$ and $\hat y$ directions, we conclude that phase separation still occurs.Comment: 8 pages, 11 figure

Translocation Dynamics with Attractive Nanopore-Polymer Interactions

Using Langevin dynamics simulations, we investigate the influence of polymer-pore interactions on the dynamics of biopolymer translocation through nanopores. We find that an attractive interaction can significantly change the translocation dynamics. This can be understood by examining the three components of the total translocation time $\tau \approx \tau_1+\tau_2+\tau_3$ corresponding to the initial filling of the pore, transfer of polymer from the \textit{cis} side to the \textit{trans} side, and emptying of the pore, respectively. We find that the dynamics for the last process of emptying of the pore changes from non-activated to activated in nature as the strength of the attractive interaction increases, and $\tau_3$ becomes the dominant contribution to the total translocation time for strong attraction. This leads to a new dependence of $\tau$ as a function of driving force and chain length. Our results are in good agreement with recent experimental findings, and provide a possible explanation for the different scaling behavior observed in solid state nanopores {\it vs.} that for the natural $\alpha$-hemolysin channel.Comment: 8 pages, 11 figure

18F-FAC PET Visualizes Brain-Infiltrating Leukocytes in a Mouse Model of Multiple Sclerosis.

Brain-infiltrating leukocytes contribute to multiple sclerosis (MS) and autoimmune encephalomyelitis and likely play a role in traumatic brain injury, seizure, and stroke. Brain-infiltrating leukocytes are also primary targets for MS disease-modifying therapies. However, no method exists for noninvasively visualizing these cells in a living organism. 1-(2'-deoxy-2'-18F-fluoroarabinofuranosyl) cytosine (18F-FAC) is a PET radiotracer that measures deoxyribonucleoside salvage and accumulates preferentially in immune cells. We hypothesized that 18F-FAC PET could noninvasively image brain-infiltrating leukocytes. Methods: Healthy mice were imaged with 18F-FAC PET to quantify if this radiotracer crosses the blood-brain barrier (BBB). Experimental autoimmune encephalomyelitis (EAE) is a mouse disease model with brain-infiltrating leukocytes. To determine whether 18F-FAC accumulates in brain-infiltrating leukocytes, EAE mice were analyzed with 18F-FAC PET, digital autoradiography, and immunohistochemistry, and deoxyribonucleoside salvage activity in brain-infiltrating leukocytes was analyzed ex vivo. Fingolimod-treated EAE mice were imaged with 18F-FAC PET to assess if this approach can monitor the effect of an immunomodulatory drug on brain-infiltrating leukocytes. PET scans of individuals injected with 2-chloro-2'-deoxy-2'-18F-fluoro-9-β-d-arabinofuranosyl-adenine (18F-CFA), a PET radiotracer that measures deoxyribonucleoside salvage in humans, were analyzed to evaluate whether 18F-CFA crosses the human BBB. Results: 18F-FAC accumulates in the healthy mouse brain at levels similar to 18F-FAC in the blood (2.54 ± 0.2 and 3.04 ± 0.3 percentage injected dose per gram, respectively) indicating that 18F-FAC crosses the BBB. EAE mice accumulate 18F-FAC in the brain at 180% of the levels of control mice. Brain 18F-FAC accumulation localizes to periventricular regions with significant leukocyte infiltration, and deoxyribonucleoside salvage activity is present at similar levels in brain-infiltrating T and innate immune cells. These data suggest that 18F-FAC accumulates in brain-infiltrating leukocytes in this model. Fingolimod-treated EAE mice accumulate 18F-FAC in the brain at 37% lower levels than control-treated EAE mice, demonstrating that 18F-FAC PET can monitor therapeutic interventions in this mouse model. 18F-CFA accumulates in the human brain at 15% of blood levels (0.08 ± 0.01 and 0.54 ± 0.07 SUV, respectively), indicating that 18F-CFA does not cross the BBB in humans. Conclusion: 18F-FAC PET can visualize brain-infiltrating leukocytes in a mouse MS model and can monitor the response of these cells to an immunomodulatory drug. Translating this strategy into humans will require exploring additional radiotracers

Polymer translocation out of confined environments

We consider the dynamics of polymer translocation out of confined environments. Analytic scaling arguments lead to the prediction that the translocation time scales like $\tau\sim N^{\beta+\nu_{2D}}R^{1+(1-\nu_{2D})/\nu}$ for translocation out of a planar confinement between two walls with separation $R$ into a 3D environment, and $\tau \sim N^{\beta+1}R$ for translocation out of two strips with separation $R$ into a 2D environment. Here, $N$ is the chain length, $\nu$ and $\nu_{2D}$ are the Flory exponents in 3D and 2D, and $\beta$ is the scaling exponent of translocation velocity with $N$, whose value for the present choice of parameters is $\beta \approx 0.8$ based on Langevin dynamics simulations. These scaling exponents improve on earlier predictions.Comment: 5 pages, 5 figures. To appear in Phys. Rev.