Determining dust temperatures and masses in the Herschel era: The importance of observations longward of 200 micron

Context. The properties of the dust grains (e.g., temperature and mass) can be derived from fitting far-IR SEDs (≥100 μm). Only with SPIRE on Herschel has it been possible to get high spatial resolution at 200 to 500 μm that is beyond the peak (~160 μm) of dust emission in most galaxies. Aims. We investigate the differences in the fitted dust temperatures and masses determined using only 200 μm data (new SPIRE observations) to determine how important having >200 μm data is for deriving these dust properties. Methods. We fit the 100 to 350 μm observations of the Large Magellanic Cloud (LMC) point-by-point with a model that consists of a single temperature and fixed emissivity law. The data used are existing observations at 100 and 160 μm (from IRAS and Spitzer) and new SPIRE observations of 1/4 of the LMC observed for the HERITAGE key project as part of the Herschel science demonstration phase. Results. The dust temperatures and masses computed using only 100 and 160 μm data can differ by up to 10% and 36%, respectively, from those that also include the SPIRE 250 & 350 μm data. We find that an emissivity law proportional to λ^(−1.5) minimizes the 100–350 μm fractional residuals. We find that the emission at 500 μm is ~10% higher than expected from extrapolating the fits made at shorter wavelengths. We find the fractional 500 μm excess is weakly anti-correlated with MIPS 24 μm flux and the total gas surface density. This argues against a flux calibration error as the origin of the 500 μm excess. Our results do not allow us to distinguish between a systematic variation in the wavelength dependent emissivity law or a population of very cold dust only detectable at λ ≥ 500 μm for the origin of the 500 μm excess

Bioeconomic analysis of protected area use in fisheries management

Protected areas in fishery management have been suggested to hedge management failures and variation in harvests. In this paper, a stochastic bioeconomic model of a two-species fishery in the Manning Bioregion is used to test the performance of protected areas as a management tool in a fishery. The establishment of a protected area is analysed under the assumption of heterogenous environments that are linked via density-dependent or sink-source stock dispersal relationships. The sensitivity of the results to different degrees of management is also explored. The model is applied to the Ocean Prawn Trawl, and Ocean Trap and Line fisheries within Manning Bioregion in New South Wales, Australia. The focus of the study is placed on the biological and institutional characteristics that yield benefits to the fishery. It was found that protected area use in the Manning Bioregion is likely to have differing effects on the two fisheries examined, benefiting Ocean Trap and Line fishers but adversely affecting Ocean Prawn Trawl fishers. Overall, it is unlikely that protected area use will lead to an increase resource rent in the fishery.bioeconomics, fisheries management, marine protected areas, Resource /Energy Economics and Policy,

A Bioeconomic Analysis of Protected Area use in Fisheries Management

The use of protected areas as a fishery management tool has been suggested as a hedge against management failures and variation in harvests. A stochastic bioeconomic model of a two-species fishery will be used to test the performance of protected areas as a management tool in a fishery with heterogenous environments. Protected areas are analysed under density-dependent and sink-source dispersal relationships between environments within the fishery. Differing levels of management control over fishery resource extraction are analysed. The model is applied to Manning Bioregion in NSW. The focus of the study is placed on the biological and institutional characteristics that yield benefits to the fishery.Resource /Energy Economics and Policy,

Tariffs and Steel: The US Safeguard Actions

This paper presents a multi-product price linked spatial equilibrium model of world steel trade. The model is used to analyse the impacts of the safeguard trade barriers brought about by the United States in order to protect their domestic industry from so called unfair competition. Emphasis is placed on the likely effect to the Australian industry and possible policy responses available to the industry. A case study is made on Australia's three largest export products, namely slab, hot-rolled and cold-rolled steel, which share some substitutability in supply and demand due to the nature of the industry.trade, spatial equilibrium model, steel, International Relations/Trade,

Tariffs and steel: US safeguard actions

A multiproduct spatial equilibrium model of world steel trade is presented in this paper. The model is used to analyse the impacts of the safeguard trade barriers brought about by the USA in order to protect their domestic industry from the so-called unfair competition. Emphasis is placed on the likely effect on the Australian industry and possible policy responses available to the industry. A case study is made of Australia’s three largest export products; namely, slab, hot-rolled and cold-rolled steel, which share some substitutability in supply and demand because of the nature of the industry. As a result of the safeguard barriers to steel trade, world steel prices fell and trade shifted away from the USA to other importing regions.spatial equilibrium model, steel, trade, International Relations/Trade,

Non-commutative Gross-Neveu model at large N

The non-commutative O(N) Gross-Neveu model is solved in the large N limit in two and three space-time dimensions. The commutative version of the two dimensional model is a renormalizable quantum field theory, both in a coupling constant expansion and an expansion in 1/N. The non-commutative version has a renormalizable coupling constant expansion where ultraviolet divergences can be removed by adjusting counterterms to each order. On the other hand, in a previous work, we showed that the non-commutative theory is not renormalizable in the large N expansion. This is argued to be due to a combined effect of asymptotic freedom and the ultraviolet/infrared mixing that occurs in a non-commutative field theory. In the present paper we will elaborate on this result and extend it to study the large N limit of the three dimensional Gross-Neveu model. We shall see that the large N limit of the three dimensional theory is also trivial when the ultraviolet cutoff is removed.Comment: 23 page

Untangling the Benefits of Protected Areas in Fisheries

Studies of marine protected areas as a tool for fisheries management have shown that protected areas have the potential to improve the level of resource rent generated in the fishery. The benefits to the fishery from protected areas have been shown to increase with sub-optimal management. However, some benefit that is derived from protected area creation in these circumstances is attributed to changes in effort levels. Both unique benefits, such as the hedge benefits of protected area creation, and non-unique benefits, such as shifts in effort levels towards optimal levels, are explored. Examples are taken from analysis of protected area creation in a predator-prey meta-population fishery under several different scenarios. It is suggested that much of the gain from protected area creation under sub-optimal management can be attributed to non-unique benefits, with the policy implications of this analysis also explored.Bioeconomics, fisheries management, marine protected areas, Environmental Economics and Policy, Q22,

Marine Protected Areas in Fisheries Management

The use of protected areas as a fishery management tool has been suggested as a hedge against management failures and variation in harvests. A stochastic bioeconomic model of a two-species fishery will be used to test the performance of protected areas as a management tool in a fishery with heterogenous environments. Protected areas are analysed under density-dependent and sink-source dispersal relationships between environments within the fishery. The model is applied to Manning Bioregion in NSW. Protected area performance as a tool for fisheries will be analysed given the existing management arrangement. The focus of the study is placed on the biological and economic characteristics that yield benefits to the fishery.Fisheries, Fisheries management, bioeconomics, marine protected areas, Resource /Energy Economics and Policy, Q2, Q22, Q28, Q57,

The Impact of Late-Career Health and Employment Shocks on Social Security and Other Wealth

About one-quarter of workers age 51 to 55 in 1992 developed health-related work limitations and about one-fifth were laid off from their jobs before age 62. Although late-career health and employment shocks often derail retirement savings plans, Social Security's disability insurance, spouse and survivor benefits, and progressive benefit formula provide important protections. In fact, health shocks increase Social Security's lifetime value, primarily because the system's disability insurance allows some disabled workers to collect benefits before age 62. However, if the system's disability insurance program did not exist, the onset of health-related work limitations would substantially reduce Social Security wealth

Life History, Diet, Abundance and Distribution, and Length-Frequencies of Selected Invertebrates in Florida Bay, Everglades National Park, Florida

This report presents information on the life history, diet, abundance and distribution, and length-frequency distributions of five invertebrates in Florida Bay, Everglades National Park. Collections were made with an otter trawl in basins on a bi-monthly basis. Non-parametric statistics were used to test spatial and temporal differences in the abundance of invertebrates when numbers were appropriate (i. e., $25). Invertebrate species are presented in four sections. The sections on Life History, and Diet were derived from the literature. The section on Abundance and Distribution consists of data from otter-trawl collections. In addition, comparisons with other studies are included here following our results. The section on Length-frequency Distributions consists of length measurements from all collections, except 1984-1985 when no measurements were taken. Length-frequency distributions were used, when possible, to estimate life stage captured, spawning times, recruitment into Florida Bay for those species which spawn outside the Bay, and growth. Additional material from the literature was added when appropriate. (PDF contains 39 pages