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Comparable Estimates (comparable + estimate)
Selected AbstractsPoverty lines around the world: A new methodology and internationally comparable estimatesINTERNATIONAL LABOUR REVIEW, Issue 4 2006Richard ANKER First page of article [source] Movements and foraging effort of Steller's Eiders and Harlequin Ducks wintering near Dutch Harbor, AlaskaJOURNAL OF FIELD ORNITHOLOGY, Issue 2 2007John A. Reed ABSTRACT We studied the movements and foraging effort of radio-marked Steller's Eiders (Polysticta stelleri) and Harlequin Ducks (Histrionicus histrionicus) to evaluate habitat quality in an area impacted by industrial activity near Dutch Harbor, Alaska. Foraging effort was relatively low, with Steller's Eiders foraging only 2.7 ± 0.6 (SE) hours per day and Harlequin Ducks 4.1 ± 0.5 hours per day. Low-foraging effort during periods of high-energetic demand generally suggests high food availability, and high food availability frequently corresponds with reductions in home range size. However, the winter ranges of Harlequin Ducks did not appear to be smaller than usual, with the mean range size in our study (5.5 ± 1.1 km2) similar to that reported by previous investigators. The mean size of the winter ranges of Steller's Eiders was similar (5.1 ± 1.3 km2), but no comparable estimates are available. Eutrophication of the waters near Dutch Harbor caused by seafood processing and municipal sewage effluent may have increased populations of the invertebrate prey of these sea ducks and contributed to their low-foraging effort. The threat of predation by Bald Eagles (Haliaeetus leucocephalus) that winter near Dutch Harbor may cause Steller's Eiders and Harlequin Ducks to move further offshore when not foraging, contributing to an increase in range sizes. Thus, the movement patterns and foraging behavior of these ducks likely represent a balance between the cost and benefits of wintering in a human-influenced environment. SINOPSIS Estudiamos los movimientos y esfuerzo de forrajeo de individuos de eidero (Polusticta stelleri) y el pato arlequín (Histrionicus histrionicus)(ambos con radiotransmisores) para evaluar la calidad del habitat en un área impactada por actividad industrial localizada en Dutch Harbor, Alaska. El esfuerzo de forrajeo (en horas/dia) fue bajo en el eidero con 2.7 ± 0.6 y en el arlequín 4.1 ± 0.5. Un bajo esfuerzo de forrajeo durante periodos de alta demanda energética por lo general sugieren una buena cantidad y calidad de alimentos. Alimentos en abundancia por lo general dan origen a una reducción en el ambiente ocupado (home range). Sin embargo, el ambiente ocupado del arlequín fue de 5.5 ± 1.1 km cuadrados, similar al informado en otros estudios, por lo que no parece haberse reducido. En el eidero el tamaño del área ocupada fue de 5.1 ± 1.3 km cuadrados y no hay otros estudios que nos permitieran hacer comparaciones. La eutroficación de las aguas en los alrededores de Dutch Harbor, causado por el procesamiento de pescado y las aguas usadas municipales, pueden haber incrementado los invertebrados de los cuales se alimentan ambas especies de aves estudiadas, y haber contrubuido al bajo esfuerzo de forrajeo observado en estas. El peligro de ser depredados por individuos de Haliaeetus leucocephalus, que pasan el invierno en el área de la bahía, puede haber sido el responsable del movimiento de las aves tierra adentro, cuando no se estaban alimentando, contribuyendo al tamaño del área ocupada por ambas especies. Por ende los movimientos y patrones de forrajeo de ambas especies probablemente no representa un balance entre el costo y los beneficios de pasar el invierno en un ambiente influenciado por la presencia de humanos. [source] Parentage versus two-generation analyses for estimating pollen-mediated gene flow in plant populationsMOLECULAR ECOLOGY, Issue 8 2005JAROSLAW BURCZYK Abstract Assessment of contemporary pollen-mediated gene flow in plants is important for various aspects of plant population biology, genetic conservation and breeding. Here, through simulations we compare the two alternative approaches for measuring pollen-mediated gene flow: (i) the neighborhood model , a representative of parentage analyses, and (ii) the recently developed twogener analysis of pollen pool structure. We investigate their properties in estimating the effective number of pollen parents (Nep) and the mean pollen dispersal distance (,). We demonstrate that both methods provide very congruent estimates of Nep and ,, when the methods' assumptions considering the shape of pollen dispersal curve and the mating system follow those used in data simulations, although the neighborhood model exhibits generally lower variances of the estimates. The violations of the assumptions, especially increased selfing or long-distance pollen dispersal, affect the two methods to a different degree; however, they are still capable to provide comparable estimates of Nep. The neighborhood model inherently allows to estimate both self-fertilization and outcrossing due to the long-distance pollen dispersal; however, the twogener method is particularly sensitive to inflated selfing levels, which in turn may confound and suppress the effects of distant pollen movement. As a solution we demonstrate that in case of twogener it is possible to extract the fraction of intraclass correlation that results from outcrossing only, which seems to be very relevant for measuring pollen-mediated gene flow. The two approaches differ in estimation precision and experimental efforts but they seem to be complementary depending on the main research focus and type of a population studied. [source] ESTIMATING THE VALUE OF DELIVERY OPTIONS IN FUTURES CONTRACTSTHE JOURNAL OF FINANCIAL RESEARCH, Issue 3 2005Jana Hranaiova Abstract We analyze the effect various delivery options embedded in commodity futures contracts have on the futures price. The two embedded options considered are the timing and location options. We show that early delivery is always optimal when only a timing option is present, but not so when joint options are present. The estimates of the combined options are much smaller than the comparable estimates for the timing option alone. The average value of the joint option is about 5% of the average basis on the first day of the maturity month. This suggests that joint options can increase deliverable supplies while potentially having only a small effect on basis behavior. [source] An Economic Analysis of the Returns to Canadian Swine Research: 1974,97CANADIAN JOURNAL OF AGRICULTURAL ECONOMICS, Issue 2 2001Greg Thomas This paper reports a new set of estimates of the returns to swine research in Canada. These estimates are obtained using Agriculture and Agri-Food Canada's Canadian Regional Agricultural Model (CRAM). Positive Mathematical Programming is incorporated into the model for use in this study. The CRAM allows the effects of supply shifts from technological change in the hog industry to interact with product and factor market conditions in the rest of Canadian agriculture. Extensive sensitivity analysis is conducted to examine the robustness of the return estimates under variations in some of the key assumptions employed in the analysis. The costs of public and private sector swine research are estimated. Public sector research costs are inclusive of the marginal excess burden of taxation. Overall, the estimated benefits from Canadian swine research are high relative to the estimated costs for the time period considered. Previous estimates of the returns to Canadian swine research were obtained by Huot et al. (1989) with a partial equilibrium model that did not allow for intra-sectoral resource use adjustments. The estimated returns obtained in the present study are generally higher than those obtained by Huot et al. For example, the estimates obtained from the direct application of the econometrically estimated supply function in this study gave an internal rate of return of about 124% and a benefit-cost ratio of 22.4 to 1. Huot et al reported comparable estimates of about 43% for the internal rate of return and 6,7 to 1 for the benefit-cost ratio. The differences in returns are not solely attributable to the use of a multi-market versus a single-market partial equilibrium approach. There are also differences in the estimates of the marginal excess burden of taxation between the two studies. L'analyse que void présente une nouvelle série d'estimations quant au rendement de la recherche porcine au Canada. Ces estimations dérivent du Modèle d'analyse régionale de l'agriculture du Canada (MARAC) du ministère canadien de l'Agriculture et de l'Agroalimentaire. Aux fins de la présente étude, on avait intégré au modèle une programmation mathématique positive. Le MARAC autorise l'interaction entre les retombées d'une modification de l'offre attribuable au virage technologique de l'industrie porcine et les conditions du marché des produits et des facteurs dans le reste de l'agriculture canadienne. Les auteurs ont effectué une analyse de sensibilité poussée en vue d'établir la robustesse de leurs estimations quand variaient quelques-unes des principales hypotheses de l'analyse. On a estimé le coût de la recherche sur les pores poursuivie par les secteurs public et privé. Dans le secteur public, le coût de la recherche incluait une charge fiscale légérement excessive. Dans l'ensemble, la recherche sur les porcs entreprise au Canada a rapporté beaucoup comparativement à ce qu'elle a coûté pendant la période à l'étude. Les estimations antérieures, établies par Huot et ses collaborateurs (1989), venaient d'un modèle àéquilibre partiel ne permettant aucun ajustement pour l'utilisation intra-sectorielle des ressources. Les revenus estimés ici sont généralement plus élevés que ceux de Huot et de ses collaborateurs. Ainsi, une application directe de l'offre estimée par des méthodes économétriques à l'analyse donne un taux de rendement interne d'environ 124 % et un indice de rentabilité de 22,4 pour 1. À titre de comparaison, Huot et ses collaborateurs rapportent des résultats d'environ 43 % pour le taux de rendement interne et de 6 à 7 pour 1 en ce qui concerne l'indice de rentabilité. Pareil écart ne résulte pas uniquement du choix d'un modèle àéquilibre partiel reposant sur plusieurs marchés au lieu d'un seul; on relève aussi des variations dans l'estimation du léger excès de la charge fiscale entre les deux études. [source] | |||||||||||||