125 research outputs found
CHOICE AND TEMPORAL WELFARE IMPACTS: DYNAMIC GEV DISCRETE CHOICE MODELS
Welfare economics is often employed to measure the impact of economic policies or externalities. When demand is characterized by discrete choices, static models of consumer demand are employed for this type of analysis because of the difficulty in estimating dynamic discrete choice models. In this paper we provide a tractable approach to estimating dynamic discrete choice models of the Generalized Extreme Value (GEV) family that addresses many of the problems identified in the literature and provides a rich set of parameters describing dynamic choice. We apply this model to the case of recreational fishing site choice, comparing dynamic to static versions. In natural resource damage assessment cases, static discrete choice models of recreational site choice are often employed to calculate welfare measures, which will be biased if the underlying preferences are actually dynamic in nature. In our empirical case study we find that the dynamic model provides a richer behavioral model of site choice, and reflects the actual choices very well. We also find significant differences between static and dynamic welfare measures. However, we find that the dynamic model raises several concerns about the specification of the policy impact and the subsequent welfare measurement that are not raised in static cases.Demand and Price Analysis,
Estimating society's willingness to pay to maintain viable rural communities
Declining populations in rural and regional areas have become a high political priority in Australia. Calls for measures to support rural communities have been prompted by substantial population declines in some country areas. In Europe and the USA, similar political pressures to halt population losses in rural and regional areas are also apparent; often as a component of the multifunctionality of agriculture. The question addressed in the present paper is whether or not the Australian tax‐paying public would be willing to pay to avoid losses of people from rural and regional areas that may result from environmental protection measures. As an integral component of two recent non‐market, environmental valuation exercises using Choice Modelling, the value of the benefits associated with the maintenance of rural populations has been estimated. The results demonstrate that a positive existence value is held primarily by urban dwellers for rural population levels.Community/Rural/Urban Development,
Tough times call for a review of farm business performance
Most Australian farm businesses specialising in wool production are operating at a loss at current wool prices. After both short term operating and long term costs of capital depreciation are accounted for, only a small number of wool growers are able to make a profit with the wool market indicator below 500c/kg.
Poor prices have stimulated wool growers to review their operations and look to ways of improving cash flow in the short term, such as diversifying into cropping. The downturn should also prompt growers to address the longer term trends of declining terms of trade and historically poor productivity growth in the sheep industry relative to cropping specialists.
This article evaluates the potential gains to be made by diversifying into high yield cropping. It also examines several possible ways that wool growers can address the declining terms of trade. These include productivity improvements, increasing farm size to attain economies of scale, and increasing prices received for products through improving quality and marketing
Manipulation and removal of defects in spontaneous optical patterns
Defects play an important role in a number of fields dealing with ordered
structures. They are often described in terms of their topology, mutual
interaction and their statistical characteristics. We demonstrate theoretically
and experimentally the possibility of an active manipulation and removal of
defects. We focus on the spontaneous formation of two-dimensional spatial
structures in a nonlinear optical system, a liquid crystal light valve under
single optical feedback. With increasing distance from threshold, the
spontaneously formed hexagonal pattern becomes disordered and contains several
defects. A scheme based on Fourier filtering allows us to remove defects and to
restore spatial order. Starting without control, the controlled area is
progressively expanded, such that defects are swept out of the active area.Comment: 4 pages, 4 figure
Novel human antibody therapeutics: The age of the Umabs
Monoclonal antibodies represent a major and increasingly important category of biotechnology products for the treatment of human diseases. The state-of-the-art of antibody technology has evolved to the point where therapeutic monoclonal antibodies, that are practically indistinguishable from antibodies induced in humans, are routinely generated. We depict how our science-based approach can be used to further improve the efficacy of antibody therapeutics, illustrated by the development of three monoclonal antibodies for various cancer indications: zanolimumab (directed against CD4), ofatumumab (directed against CD20) and zalutumumab (directed against epidermal growth factor receptor)
Clinical, radiologic, pathologic, and molecular characteristics of long-term survivors of diffuse intrinsic pontine glioma (DIPG): a collaborative report from the International and European Society for Pediatric Oncology DIPG registries
Purpose Diffuse intrinsic pontine glioma (DIPG) is a brainstem malignancy with a median survival of < 1 year. The International and European Society for Pediatric Oncology DIPG Registries collaborated to compare clinical, radiologic, and histomolecular characteristics between short-term survivors (STSs) and long-term survivors (LTSs). Materials and Methods Data abstracted from registry databases included patients from North America, Australia, Germany, Austria, Switzerland, the Netherlands, Italy, France, the United Kingdom, and Croatia. Results Among 1,130 pediatric and young adults with radiographically confirmed DIPG, 122 (11%) were excluded. Of the 1,008 remaining patients, 101 (10%) were LTSs (survival ≥ 2 years). Median survival time was 11 months (interquartile range, 7.5 to 16 months), and 1-, 2-, 3-, 4-, and 5-year survival rates were 42.3% (95% CI, 38.1% to 44.1%), 9.6% (95% CI, 7.8% to 11.3%), 4.3% (95% CI, 3.2% to 5.8%), 3.2% (95% CI, 2.4% to 4.6%), and 2.2% (95% CI, 1.4% to 3.4%), respectively. LTSs, compared with STSs, more commonly presented at age < 3 or > 10 years (11% v 3% and 33% v 23%, respectively; P < .001) and with longer symptom duration ( P < .001). STSs, compared with LTSs, more commonly presented with cranial nerve palsy (83% v 73%, respectively; P = .008), ring enhancement (38% v 23%, respectively; P = .007), necrosis (42% v 26%, respectively; P = .009), and extrapontine extension (92% v 86%, respectively; P = .04). LTSs more commonly received systemic therapy at diagnosis (88% v 75% for STSs; P = .005). Biopsies and autopsies were performed in 299 patients (30%) and 77 patients (10%), respectively; 181 tumors (48%) were molecularly characterized. LTSs were more likely to harbor a HIST1H3B mutation (odds ratio, 1.28; 95% CI, 1.1 to 1.5; P = .002). Conclusion We report clinical, radiologic, and molecular factors that correlate with survival in children and young adults with DIPG, which are important for risk stratification in future clinical trials
Agronomic performance of two generations (F12 and F13) of thirteen winter wheat composite cross wheat populations with differing cultivation histories in 2014/15.
As environmental and agronomic conditions are heterogeneous between and within locations, diversity within varieties or crop populations should increase adaptability to the changing and variable range of growing environments. The additional pressure of plant genetic diversity loss, has driven novel breeding approaches such as Composite Cross Populations (CCPs) and other genotype mixtures, thereby increasing both intra- and inter-varietal diversity and ensuring a “wider adaptation” capacity for crop varieties (Döring et al., 2011). A winter wheat (Triticum aestivum L.) CCP was created by intercrossing 20 varieties in 2001, through collaboration with the Elm Farm Research Centre and the John Innes Institute. In 2005, a seed batch of the F4 was equally divided and distributed to Hungary and Germany. In 2007, it was decided to submit one of the CCPs to changes in environments every year. A pattern was developed between eight partners whereby these “cycling” populations would be grown in a plot of >100m2 and sent to the next cycling partner the following year. The aim of the project was to compare a total of 13 populations that all originated from the same seed batch in 2005, but that have been exposed to vastly different climatic conditions over time, in one site (Germany). In 2014/15, the second experimental year, saved seed from 2013 (F12) and harvested seed from 2014 (F13) were sown, in order to compare two generations in one growing season. The experimental year 2014/15 was characterized by long dry periods, particularly between February and June 2015, and under these dry conditions most populations outyielded the selected reference varieties. There was no effect of differential seed size of the two generations for most agronomic characteristics for each population. Although the harvested TGW of both the F12 and the F13 of each population was not significantly different from one another, there were still significant differences of harvested TGW between the populations in the F12. These significant differences of harvested TGW were no longer present in the F13 between each population after one year under the same management system. These results indicate that the heritability of seed size is low as has been shown before (Silvertown, 1989) and that seed size variation tends to be a result of phenotypic plasticity, which is thought to be adaptive, especially as the result of environmental variation (Marshall et al., 1985; Vaughton and Ramsey, 1998; Lehtilä and Ehrlén, 2005)
Structures, physico-chemical properties, production and (potential) applications of sucrose-derived α-d-glucans synthesized by glucansucrases
Glycoside hydrolase family 70 (GH70) glucansucrases produce α-d-glucan polysaccharides (e.g. dextran), which have different linkage composition, branching degree and size distribution, and hold potential applications in food, cosmetic and medicine industry. In addition, GH70 branching sucrases add single α-(1→2) or α-(1→3) branches onto dextran, resulting in highly branched polysaccharides with "comb-like" structure. The physico-chemical properties of these α-d-glucans are highly influenced by their linkage compositions, branching degrees and sizes. Among these α-d-glucans, dextran is commercially applied as plasma expander and separation matrix based on extensive studies of its structure and physico-chemical properties. However, such detailed information is lacking for the other type of α-d-glucans. Aiming to stimulate the application of α-d-glucans produced by glucansucrases, we present an overview of the structures, production, physico-chemical properties and (potential) applications of these sucrose-derived α-d-glucan polysaccharides. We also discuss bottlenecks and future perspectives for the application of these α-d-glucan polysaccharides
- …