Using alterative whole-farm modelling approaches to assess farm enterprise selection, risk and welfare

Using an expected mean-variance model the changes in farm enterprise levels and indirect utility were examined under conditions of risk aversion, budget constraints and gross margin variance. An extension of the comparative statics of the expected mean-variance model was adopted by introducing a budget constraint into the constrained optimisation problem. A 10-year expected mean-variance whole-farm model was solved for a farm in the wheat-sheep zone of Australia to provide an empirical example. Results were obtained using no planning horizon (the static model) and then with a five-year rolling planning horizon (the dynamic model). In addition, enterprise levels were constrained to match levels observed on the farm so as to compare incomes between the constrained and unconstrained models. For a cash constrained, risk averse, farmer it was found that they are likely to have larger expenditures than less risk averse operators in order to obtain the same indirect utility. Enterprise levels differed between the dynamic and static models, and a dynamic model was used to help explain inter-temporal decision-making. Risk aversion reduced the set of possible welfare improving production activities available to a farmer.Whole-farm modelling, enterprise selection, risk., Farm Management, Q12, C61,

Crime and Natural Resource Booms: Evidence From Unconventional Natural Gas Production

The USA has experienced a sudden expansion of oil and natural gas production due to the combination of hydraulic fracturing and horizontal drilling. The energy extraction boom has had many localized impacts, most notably in areas with substantial shale gas reserves. This paper exploits a natural experiment in the Marcellus region to examine one channel of the so-called resource curse, the effect of resource extraction on local crime. The results show that areas experiencing a natural gas extraction boom suffer an increase in overall violent crimes, while property crimes remain similar to non-boom areas. Furthermore, the violent crime increase appears to be driven primarily by increases in aggravated and sexual assaults

A heterogeneous-agent model with district-level constraints: an application to livestock development in Gansu, China

This paper develops a heterogeneous-agent model to assess the impacts of removing lucerne growing subsidies, increasing livestock numbers and including district-level equilibrium conditions on optimal farm plans in the Qingyang district of Gansu Province, China. The model is a five-year dynamic linear program that solves across 96 farm households whilst incorporating district-level constraints. The approach used allows us to observe seasonal variations in incomes, infer the distribution of a policy shock among households and highlight trade patterns at the district level. The results suggest that without lucerne growing subsidies the total area of lucerne grown by all modelled households falls by 18%. Increasing livestock numbers by 25% reduces net household incomes by 17% as changes to labour allocations reduce off-farm employment opportunities. When external trade in forages is included in the model, total livestock numbers held by all 96 households rise from 502 to 838, this highlights the benefits of integrated feed markets. Shadow prices for crop production rise when livestock numbers increase, implying that benefits exist to improving crop yields.Heterogeneous-agent model, district-level constraints, livestock, China., Farm Management,

Magnetostrictive Neel ordering of the spin-5/2 ladder compound BaMn2O3: distortion-induced lifting of geometrical frustration

The crystal structure and the magnetism of BaMn$_2$O$_3$ have been studied by thermodynamic and by diffraction techniques using large single crystals and powders. BaMn$_2$O$_3$ is a realization of a $S = 5/2$ spin ladder as the magnetic interaction is dominant along 180$^\circ$ Mn-O-Mn bonds forming the legs and the rungs of a ladder. The temperature dependence of the magnetic susceptibility exhibits well-defined maxima for all directions proving the low-dimensional magnetic character in BaMn$_2$O$_3$. The susceptibility and powder neutron diffraction data, however, show that BaMn$_2$O$_3$ exhibits a transition to antiferromagnetic order at 184 K, in spite of a full frustration of the nearest-neighbor inter-ladder coupling in the orthorhombic high-temperature phase. This frustration is lifted by a remarkably strong monoclinic distortion which accompanies the magnetic transition.Comment: 9 pages, 8 figures, 2 tables; in V1 fig. 2 was included twice and fig. 4 was missing; this has been corrected in V

Control of multiferroic domains by external electric fields in TbMnO3

The control of multiferroic domains through external electric fields has been studied by dielectric measurements and by polarized neutron diffraction on single-crystalline TbMnO$_3$. Full hysteresis cycles were recorded by varying an external field of the order of several kV/mm and by recording the chiral magnetic scattering as well as the charge in a sample capacitor. Both methods yield comparable coercive fields that increase upon cooling.Comment: 12 pages, 6 figure

Are Religion and Environmentalism Complements or Substitutes?: A Club-Based Approach

In this article, we analyze the causal link between membership in environmental groups and active participation and membership in religious groups. We use a club-based model and employ OLS and spatial econometrics with controls to test for whether membership and participation in a religious group is a substitute or complement for membership in environmental groups. Instrumental variables estimation was used as a robustness check. We found that religious participation and religious membership in evangelical groups are a substitute for environmental membership. Much of the work on environmental concerns has focused on answers to survey questions, not on membership. We used a dataset of environmental membership at the county level to perform our analysis. We further add quantitative evidence to the discussion by some researchers on the link between religion and environmentalism. In this respect, our work aims to investigate further the causal links between religion and environmentalism

Magnetically induced Ferroelectricity in Bi2_2CuO4_4

The tetragonal copper oxide Bi$_2$CuO$_4$ has an unusual crystal structure with a three-dimensional network of well separated CuO$_4$ plaquettes. This material was recently predicted to host electronic excitations with an unconventional spectrum and the spin structure of its magnetically ordered state appearing at T$_N$ $\sim$43 K remains controversial. Here we present the results of detailed studies of specific heat, magnetic and dielectric properties of Bi$_2$CuO$_4$ single crystals grown by the floating zone technique, combined with the polarized neutron scattering and high-resolution X-ray measurements. Our polarized neutron scattering data show Cu spins are parallel to the $ab$ plane. Below the onset of the long range antiferromagnetic ordering we observe an electric polarization induced by an applied magnetic field, which indicates inversion symmetry breaking by the ordered state of Cu spins. For the magnetic field applied perpendicular to the tetragonal axis, the spin-induced ferroelectricity is explained in terms of the linear magnetoelectric effect that occurs in a metastable magnetic state. A relatively small electric polarization induced by the field parallel to the tetragonal axis may indicate a more complex magnetic ordering in Bi$_2$CuO$_4$

Local Fiscal Adjustments from Depopulation: Evidence from the Post–Cold War Defense Contraction

In this paper, we estimate the long-term causal effect of population losses on local government revenue, expenditure, and debt by exploiting a quasi-exogenous change that reduced the number of US military personnel by about 40 percent between the late 1980s and 2000. Aggregating across governmental units within commuting zones, we find that real per capita total revenues and expenditures remained unchanged for remaining citizens. At the same time, however, we note several important compositional effects. First, local governments appear to have offset reductions in state intergovernmental aid by increasing property tax revenues. Second, they significantly shifted the composition of expenditures by making disproportionately large cuts in capital spending, including cuts in K–12 education, to maintain levels for current operations. Third, localities increased their long-term nonguaranteed debt to finance investments not covered by general capital outlays. Taken together, these actions run the risk of hindering a region’s relative competitiveness in the long term

Does Starting School Before Labor Day Affect High School Retention and Graduation: Evidence From Virginia\u27s Kings Dominion Law

Several states have required K-12 public schools to start after Labor Day in an effort to aid the tourism and hospitality industry. However, little is known about how these policies impact educational outcomes. We examine the impact of Virginia\u27s post-Labor Day school start law on high school retention and graduation rates. We use a difference-in-differences model to exploit exogenous variation in school division start dates. Our results show small differences of up to three weeks have little effect on high school dropout and graduation rates. Our findings inform the debate on post-Labor Day school start laws and compulsory attendance age cutoff laws

Magnetoelastic coupling in RETiO3 (RE = La, Nd, Sm, Gd, Y)

A detailed analysis of the crystal structure in RETiO3 with RE = La, Nd, Sm, Gd, and Y reveals an intrinsic coupling between orbital degrees of freedom and the lattice which cannot be fully attributed to the structural deformation arising from bond-length mismatch. The TiO6 octahedra in this series are all irregular with the shape of the distortion depending on the RE ionic radius. These octahedron distortions vary more strongly with temperature than the tilt and rotation angles. Around the Ti magnetic ordering all compounds exhibit strong anomalies in the thermal-expansion coefficients, these anomalies exhibit opposite signs for the antiferromagnetic and ferromagnetic compounds. Furthermore the strongest effects are observed in the materials close to the magnetic cross-over from antiferromagnetic to ferromagnetic order