Photometric and Spectroscopic Analysis of Young, Nearby Open Cluster Collinder 70

We present the results of a wide-field (80’ x 80’) photometric and spectroscopic survey of the young open cluster Collinder 70, which is also known as the ORI OB 1b association, centered on the central star of Orion’s belt, ε Ori (Alnilam). Seventy Coll 70 spectroscopy targets were selected from BVRIc color magnitude diagrams for observation using the CTIO HYDRA multi-object spectrograph; we aimed to identify targets exhibiting H in emission and a strong lithium 6708Å line in absorption. About a third of our targets (23/70 stars) are consistent with being youthful members of Coll 70. Intermediate resolution (R!20000) HYDRA Li I 6708Å equivalent widths and Baraffe et al. (2002) evolutionary models strongly suggest that this association is \u3c\u3c 30 Myr. Observational evidence showing that some stars exhibit primordial levels of lithium, giant-like features in low-resolution spectra and the presence of infra-red excesses indicate that the association is considerably younger than 30 Myr and is a potentially valuable target for age determination using the Lithium Depletion Boundary method

Cooperation and Cheating

In this article, we extend the variable delivery claim framework (Cross, Buccola, and Thomann, 2006) to examine the option-to-cheat, that is, the option to shift production between contracts ex post. We use this framework to provide a solution to the age-old conflict between enforcement and the cooperative tradition of providing a "home" for member produce. We show that, in contrast to Nourse's competitive yardstick hypothesis, the value of the cooperative-provided option increases as market competition intensifies. When the option-to-cheat is fairly-priced, it is Pareto improving, increasing grower returns, lowering cooperative per-unit costs and reducing contract shortfalls for investor-owned rivals at no additional per-unit cost. Our valuation framework is consistent with replication-based equilibria and is free from parametric specification of individual preference or firm cost structure.Marketing,

Economic evaluation of the eradication program for bovine viral diarrhea in the Swiss dairy sector

The aim of this study was to conduct an economic evaluation of the BVD eradication program in the Swiss dairy sector. The situation before the start of the program (herd-level prevalence: 20%) served as a baseline scenario. Production models for three dairy farm types were used to estimate gross margins as well as net production losses and expenditures caused by BVD. The total economic benefit was estimated as the difference in disease costs between the baseline scenario and the implemented eradication program and was compared to the total eradication costs in a benefit-cost analysis. Data on the impact of BVD virus (BVDV) infection on animal health, fertility and production parameters were obtained empirically in a retrospective epidemiological case-control study in Swiss dairy herds and complemented by literature. Economic and additional production parameters were based on benchmarking data and published agricultural statistics. The eradication costs comprised the cumulative expenses for sampling and diagnostics. The economic model consisted of a stochastic simulation in @Risk for Excel with 20,000 iterations and was conducted for a time period of 14 years (2008–2021)

Implicit vs. explicit incentives : theory and a case study

We derive the optimal contract between a principal and a liquidity-constrained agent in a stochastically repeated environment. The contract comprises a court-enforceable explicit bonus rule and an implicit fixed salary promise that must be self-enforcing. Since the agent's rent increases with bonus pay, the principal implements the maximum credible salary promise. Thus, the bonus increases while the salary promise and the agent's effort decrease with a higher probability of premature contract termination. We subject this mechanism to econometric testing using personnel data of an insurance company. The empirical results strongly support our theoretical predictions

An all Mach number finite volume method for isentropic two-phase flow

We present an implicit-explicit finite volume scheme for isentropic two phase flow in all Mach number regimes. The underlying model belongs to the class of symmetric hyperbolic thermodynamically compatible models. The key element of the scheme consists of a linearisation of pressure and enthalpy terms at a reference state. The resulting stiff linear parts are integrated implicitly, whereas the non-linear higher order and transport terms are treated explicitly. Due to the flux splitting, the scheme is stable under a CFL condition which determined by the resolution of the slow material waves and allows large time steps even in the presence of fast acoustic waves. Further the singular Mach number limits of the model are studied and the asymptotic preserving property of the scheme is proven. In numerical simulations the consistency with single phase flow, accuracy and the approximation of material waves in different Mach number regimes are assessed

Potentiel des friches industrielles des secteurs de gare pour un développement urbain durable. Reconversion du secteur Gare/Crêt-Taconnet à Neuchâtel.

Les friches industrielles des secteurs de gare, centrales et bien accessibles en transports publics, représentent un potentiel pour un développement de l'urbanisation autre que l'étalement urbain. Grâce à l'étude de la reconversion de la friche du secteur Gare/Crêt-Taconnet à Neuchâtel, ce travail montre qu'il est possible de concrétiser des aménagements denses et de qualité sur ces sites en déclin, participant ainsi à un développement urbain durable