Long Range Tensor Correlations in Charge and Parity Projected Fermionic Molecular Dynamics

Within the framework of Fermionic Molecular Dynamics a method is developed to better account for long range tensor correlations in nuclei when working with a single Slater determinant. Single-particle states with mixed isospin and broken parity build up an intrinsic Slater determinant which is then charge and parity projected. By minimizing the energy of this many-body state with respect to the parameters of the single-particle states and projecting afterwards on angular momentum ground state energies are obtained that are systematically lower than corresponding Hartree-Fock results. The realistic Argonne V18 potential is used and short range correlations are treated with the Unitary Correlation Operator Method. Comparison with exact few-body calculations shows that in $^4$He about one fifth of the correlation energy due to long-range correlations are accounted for. These correlations which extend over the whole nucleus are visualized with the isospin and spin-isospin density of the intrinsic state. The divergence of the spin-isospin density, the source for pion fields, turns out to be of dipole nature.Comment: 12 pages, 4 figure

Risk of kidney stones in living kidney donors: A matched cohort study

A kidney stone in a person with one kidney requires urgent attention which may result in surgical and/or hospital attention. We conducted a matched retrospective cohort study to determine if living kidney donors compared to healthy non-donors have a higher risk of: 1) kidney stones with surgical intervention, and 2) hospital encounters for kidney stones. We reviewed and linked information from pre-donation charts to Ontario healthcare databases. We selected healthy non-donors from the general population, matching ten non-donors to every donor, to generate a cohort of 2,019 donors and 20,190 non-donors. There was no difference in the rate of 1) kidney stones with surgical intervention comparing donors to non-donors (8.3 vs 9.7 events/10,000 person-years; rate ratio[RR] 0.85; 95% confidence interval[CI] 0.47-1.53), and 2) hospital encounters for kidney stones (12.1 vs 16.1 events/10,000 person-years; RR 0.75; 95% CI 0.45-1.24). These interim results are reassuring for the safety of living kidney donation

A Theory of Firm Decline

We study the problem of an investor that buys an equity stake in an entrepreneurial venture, under the assumption that the former cannot monitor the latter’s operations. The dynamics implied by the optimal incentive scheme is rich andquite different from that induced by other models of repeated moral hazard. In particular, our framework generates a rationale for firm decline. As young firms accumulate capital, the claims of both investor (outside equity) and entrepreneur (inside equity) increase. At some juncture, however, even as the latter keeps on growing, capital and firm value start declining and so does the value of outside equity. The reason is that incentive provision becomes costlier as inside equity grows. In turn, this leads to a decline in the constrained–efficient level of effort and therefore to a drop in the return to investment. In the long run, the entrepreneur gains control of all cash–flow rights and the capital stock converges to a constant value.Principal–Agent, Moral Hazard, Hidden Action, Incentives, Firm Dynamics.

A Theory of Firm Decline

We study the problem of an investor that buys an equity stake in an entrepreneurial venture, under the assumption that the former cannot monitor the latter’s operations. The dynamics implied by the optimal incentive scheme is rich and quite different from that induced by other models of repeated moral hazard. In particular, our framework generates a rationale for firm decline. As young firms accumulate capital, the claims of both investor (outside equity) and entrepreneur (inside equity) increase. At some juncture, however, even as the latter keeps on growing, invested capital and firm value start declining and so does the value of outside equity. The reason is that incentive provision is costlier the wealthier the entrepreneur (the greater is inside equity). In turn, this leads to a decline in the constrained–efficient level of effort and therefore to a drop in the return to investment.Principal Agent, Moral Hazard, Hidden Action, Incentives, Survival, Firm Dynamics

Electric dipole polarizability: from few- to many-body systems

We review the Lorentz integral transform coupled-cluster method for the calculation of the electric dipole polarizability. We benchmark our results with exact hyperspherical harmonics calculations for 4He and then we move to a heavier nucleus studying 16O. We observe that the implemented chiral nucleon-nucleon interaction at next-to-next-to-next-to-leading order underestimates the electric dipole polarizability.Comment: 4 pages, 2 figures, proceedings of the 21st International Conference on Few-Body Problems in Physics (FB21), May 2015, Chicag

Pourquoi faire simple quand on peut faire compliqué ? La perception d'un packaging alimentaire en fonction de son niveau de complexité.

International audienceThis study deals with the impact of a packaging complexity level on food product perceptions. An experimental study is led with 141 respondents, manipulating the packaging simplicity level and a claim addition. The results show that, even if the complex packaging gives yearn for food, it doesn't imply any purchase intent. On the contrary, the simple packaging improves the attitude toward the product and the purchase intent. Moreover, the claim addition is only efficient on the complex packaging.Cette étude traite de l'impact du niveau de complexité du packaging sur la perception des produits dans le domaine de l'agroalimentaire. Une étude expérimentale between subject menée auprès de 141 individus en manipulant le niveau de simplicité d'un packaging et l'apposition d'une allégation est menée. Les résultats montrent que si un packaging complexe donne plus envie de manger, il ne provoque pas l'intention d'achat. A l'inverse un packaging simple améliore l'attitude envers le produit et favorise l'achat. Par ailleurs, l'apposition d'une allégation n'est efficace que sur un packaging complexe