INVESTMENT ANALYSIS OF ALTERNATIVE FRUIT TREE SPRAYERS IN MICHIGAN ORCHARDS

Changing orchard sprayer technology and rising pesticide costs to fruit growers raise the need to analyze the profitability of alternative sprayer investments. This study analyzes investments in four orchard sprayers for use in Michigan apple production: an air blast sprayer, a tower boom sprayer, a tower boom sprayer equipped with electronic sensors that activate spray nozzles when foliage is detected, and an air curtain sprayer that targets spray with a layer of forced air. Assuming equal pest control efficacy, the study calculates the annualized net present cost per acre of owning and operating each sprayer for ten years using a baseline discount rate of 10 percent over 200 acres of semi-dwarf apple trees. The analysis found the annualized net present cost per acre, from least to greatest, to be $287 for the air curtain sprayer,$312 for the tower sprayer with electronic sensors, $345 for the plain tower sprayer, and$391 for the conventional air blast sprayer. Sensitivity analysis revealed that the ranking of these cost results was sensitive to farm size, but not to percentage of funds borrowed, discount rate, loan interest rate, or pesticide costs within the ranges investigated. The air curtain sprayer was lowest cost for orchards of 25 acres or more; the conventional air blast sprayer was lowest cost for 10-acre orchards.Crop Production/Industries,

Connecting species’ geographical distributions to environmental variables: range maps versus observed points of occurrence

Connecting the geographical occurrence of a species with underlying environmental variables is fundamental for many analyses of life history evolution and for modeling species distributions for both basic and practical ends. However, raw distributional information comes principally in two forms: points of occurrence (specific geographical coordinates where a species has been observed), and expert-prepared range maps. Each form has potential short-comings: range maps tend to overestimate the true occurrence of a species, whereas occurrence points (because of their frequent non-random spatial distribution) tend to underestimate it. Whereas previous comparisons of the two forms have focused on how they may differ when estimating species richness, less attention has been paid to the extent to which the two forms actually differ in their representation of a species’ environmental associations. We assess such differences using the globally distributed avian order Galliformes (294 species). For each species we overlaid range maps obtained from IUCN and point-of-occurrence data obtained from GBIF on global maps of four climate variables and elevation. Over all species, the median difference in distribution centroids was 234 km, and median values of all five environmental variables were highly correlated, although there were a few species outliers for each variable. We also acquired species’ elevational distribution mid-points (mid-point between minimum and maximum elevational extent) from the literature; median elevations from point occurrences and ranges were consistently lower (median −420 m) than mid-points. We concluded that in most cases occurrence points were likely to produce better estimates of underlying environmental variables than range maps, although differences were often slight. We also concluded that elevational range mid-points were biased high, and that elevation distributions based on either points or range maps provided better estimates

The classical limit for a class of quantum baker's maps

We show that the class of quantum baker's maps defined by Schack and Caves have the proper classical limit provided the number of momentum bits approaches infinity. This is done by deriving a semi-classical approximation to the coherent-state propagator.Comment: 18 pages, 5 figure

Regulated Commercial Harvest to Manage Overabundant White-Tailed Deer: An Idea to Consider?

Dramatic growth in numbers of white-tailed deer (Odocoileus virginianus) and declines in hunter recruitment have challenged our ability to manage deer populations through traditional methods. We surveyed all state wildlife agencies and estimate the current abundance of white-tailed deer in North America exceeds 30 million. States currently are issuing record numbers of permits to hunters to increase harvest of white-tailed deer. Unfortunately, hunter participation has been declining in North America during the past two decades. Traditional methods of population management have been ineffective in reducing numbers of deer sufficiently in some environments. Regulated commercial harvest would help state wildlife agencies manage overabundant populations of white-tailed deer and allow licensed hunters to sell all or parts of harvested deer. We anticipate that many will criticize regulated commercial harvest of deer and claim that it is contrary to the North American Model of Wildlife Conservation (NAMWC). We feel, however, that regulated commercial harvest meets all seven of the pillars of the NAMWC: 1) Wildlife is a natural resource of the public trust (state wildlife agencies will manage deer and deer would continue to be a public resource). 2) No commercial use of wildlife [a direct reaction to exploitive and unsustainable market hunting in the 18th and 19th Centuries; commercial markets currently exist for other natural resources (e.g., furbearers, fish, timber); contemporary conservation values would not allow overexploitation; a framework for regulations, monitoring, and enforcement already is in place in every state]. 3) Democratic rule of law to regulate use of wildlife (commercial harvest of white-tailed deer would be highly regulated by wildlife agencies through public processes). 4) Hunting opportunity for all (anyone legally able to hold a deer hunting license would be eligible to apply for a Commercial Deer Harvest License (CDHL), CDHL programs would be implemented only where recreational hunting is inefficient or inappropriate). 5) No frivolous use of wildlife (CDHLs will be used to generate food and other products, management would address risks to human health and safety and losses of agricultural resources to deer). 6) Wildlife is an international resource [has little to do with our proposed idea of managing overabundant resident populations of white-tailed deer, but a CDHL program may be applicable to any overabundant species, including internationally migratory species, such as snow geese (Chen caerulescens)]. 7) Science-based wildlife policy (a CDHL program would rely on science and research-based data to estimate densities before, during, and after commercial harvest). A CDHL program should be managed and distributed by state wildlife agencies, issue permits only to qualified individuals, enable harvest of an allotment of deer in areas targeted for population reduction, and permit the sale of whole carcasses and parts of harvested deer. Administration of a CDHL program will be taxing. State agencies are understaffed, but administrative and enforcement frameworks already exist for commercial harvest of publicly owned natural resources (e.g. furbearers, fish, timber) and the processing and handling of meat (e.g., USDA inspections). Revenue generated by CDHL programs could be directed back to agencies and personnel that administer and oversee programs. We anticipate several issues that must be addressed for regulated commercial harvest of deer to be accepted by agencies, hunters, and the public. State laws and regulations will need to be reviewed and some will have to be changed. Some will argue that we do not have the strength, stamina, or political will necessary to implement such broad sweeping changes. On the other hand, many wildlife managers will appreciate having an alternative tool for managing overabundant populations of white-tailed deer. Several benefits (reduce overabundant populations of deer; source of healthy, natural, green, locally-produced protein; economic growth, entrepreneurship, and market expansion; and public engagement and appreciation) and concerns (privatization of wildlife; overexploitation; food safety; competition with existing commodities; law enforcement; challenges of changing laws, regulations, and attitudes) are associated with this concept. We encourage a professional discussion of regulated commercial harvest to address the issue of overabundant white-tailed deer

On the Age and Metallicity Estimation of Spiral Galaxies Using Optical and Near-Infrared Photometry

In integrated-light, some color-color diagrams that use optical and near-infrared photometry show surprisingly orthogonal grids as age and metallicity are varied, and they are coming into common usage for estimating the average age and metallicity of spiral galaxies. In this paper we reconstruct these composite grids using simple stellar population models from several different groups convolved with some plausible functional forms of star formation histories at fixed metallicity. We find that the youngest populations present (t<2 Gyr) dominate the light, and because of their presence the age-metallicity degeneracy can be partially broken with broad-band colors, unlike older populations. The scatter among simple stellar population models by different authors is, however, large at ages t<2 Gyr. The dominant uncertainties in stellar population models arise from convective core overshoot assumptions and the treatment of the thermally pulsing asymptotic giant branch phase and helium abundance may play a significant role at higher metallicities. Real spiral galaxies are unlikely to have smooth, exponential star formation histories, and burstiness will cause a partial reversion to the single-burst case, which has even larger model-to-model scatter. Finally, it is emphasized that the current composite stellar population models need some implementation of chemical enrichment histories for the proper analysis of the observational data.Comment: 33 pages, 15 figures. Accepted to ApJ (Apr 2007). The major surgery was Fig. 1

Linear Perturbations in Brane Gas Cosmology

We consider the effect of string inhomogeneities on the time dependent background of Brane Gas Cosmology. We derive the equations governing the linear perturbations of the dilaton-gravity background in the presence of string matter sources. We focus on long wavelength fluctuations and find that there are no instabilities. Thus, the predictions of Brane Gas Cosmology are robust against the introduction of linear perturbations. In particular, we find that the stabilization of the extra dimensions (moduli) remains valid in the presence of dilaton and string perturbations.Comment: 17 pages, 1 figur

Towards a developmental state? Provincial economic policy in South Africa

This paper explores the meaning of the developmental state for spatial economic policy in South Africa. Two main questions are addressed: do provincial governments have a role to play in promoting economic prosperity, and to what extent do current provincial policies possess the attributes of a developmental state? These attributes are defined as the ability to plan longer term, to focus key partners on a common agenda, and to mobilise state resources to build productive capabilities. The paper argues that the developmental state must harness the power of government at every level to ensure that each part of the country develops to its potential. However, current provincial capacity is uneven, and weakest where support is needed most. Many provinces seem to have partial strategies and lack the wherewithal for sustained implementation. Coordination across government appears to be poor. The paper concludes by suggesting ways provincial policies could be strengthened

Verifying multi-partite mode entanglement of W states

We construct a method for verifying mode entanglement of N-mode W states. The ideal W state contains exactly one excitation symmetrically shared between N modes, but our method takes the existence of higher numbers of excitations into account, as well as the vacuum state and other deviations from the ideal state. Moreover, our method distinguishes between full N-party entanglement and states with M-party entanglement with M<N, including mixtures of the latter. We specialize to the case N=4 for illustrative purposes. In the optical case, where excitations are photons, our method can be implemented using linear optics.Comment: 11 pages, 12 figure