Interpolation methods for geographical data: Housing and commercial establishment markets

The estimation of commercial property prices in a touristic city can be explored through spatial interpolation methods, but in the presence of small sample sizes, auxiliary stochastic processes that are correlated with the prices of commercial establishments are needed. The aim of this paper is to compare the various estimates of commercial establishment prices in Toledo (Spain) provided by methods based on inverse distance weighting, 2-D shape functions for triangles, kriging and cokriging (the housing prices being the auxiliary stochastic process). The results indicate that kriging improves the classical interpolation methods and that cokriging has a clear advantage over kriging.

On the maximum bias functions of MM-estimates and constrained M-estimates of regression

We derive the maximum bias functions of the MM-estimates and the constrained M-estimates or CM-estimates of regression and compare them to the maximum bias functions of the S-estimates and the $\tau$-estimates of regression. In these comparisons, the CM-estimates tend to exhibit the most favorable bias-robustness properties. Also, under the Gaussian model, it is shown how one can construct a CM-estimate which has a smaller maximum bias function than a given S-estimate, that is, the resulting CM-estimate dominates the S-estimate in terms of maxbias and, at the same time, is considerably more efficient.Comment: Published at http://dx.doi.org/10.1214/009053606000000975 in the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

Factorization and Criticality in Finite XXZ Systems of Arbitrary Spin

We analyze ground state (GS) factorization in general arrays of spins si with XXZ couplings immersed in nonuniform fields. It is shown that an exceptionally degenerate set of completely separable symmetry-breaking GSs can arise for a wide range of field configurations, at a quantum critical point where all GS magnetization plateaus merge. Such configurations include alternating fields as well as zero-bulk field solutions with edge fields only and intermediate solutions with zero field at specific sites, valid for d-dimensional arrays. The definite magnetization-projected GSs at factorization can be analytically determined and depend only on the exchange anisotropies, exhibiting critical entanglement properties. We also show that some factorization-compatible field configurations may result in field-induced frustration and nontrivial behavior at strong fields.Fil: Cerezo, M. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Rossignoli, Raúl Dante. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Canosa, Norma Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Ríos, E.. Universidad Tecnológica Nacional; Argentin

Consumers' Perceptions about Food Quality Attributes and Their Incidence in Argentinean Organic Choices

There is an increasing consumers' concern for food safety and quality and, at the same time, there has been a significant market increment in differentiated or high value products consumption, including organic products. The lack of empirical research in Argentina regarding consumers' awareness of food safety brought our attention. Therefore, the objective of this paper is to analyse consumers' perceptions about the risk and quality attributes of food consumption; and to evaluate the incidence of these factors when buying organic products in Argentina. The Lancaster model (1966) provided the theoretical basis for the use of products attributes and characteristics to analyse the incidence of these attributes in consumers' choices. The data used in this study derives from a food consumption survey on organic and non-organic consumers conducted in Buenos Aires City, Argentina, in April 2005. According to consumers' perceptions, 67% were worried about their health, 79% take care in meals, 57% perceived the high risk of hormones and pesticides in food content and 91% of consumers are used to reading labels before or during their purchase. A Logit Binomial Regression Model was applied to explore which factors affected organic food consumption. The results yielded by this model suggest that the consumers with higher educational level, who eat healthy food, and consider food control organisms 'inefficient' are more likely to buy organic products. A high percentage of consumers read and trust label information in Argentina. This has interesting policy implications to promote differentiated and high value products, and to reduce information asymmetries.Food safety, Quality attributes, Consumers, Organics, Food Consumption/Nutrition/Food Safety, Q18, D1,

Contingent Valuation of Consumers’ Willingness-to-Pay for Organic Food in Argentina

Throughout these last years, organic agriculture has undergone a remarkable expansion due, among other things, to the greater interest shown by consumers aware of food safety concerns involving real or perceived quality risks [1]. This paper aims to estimate consumers’ willingness to pay (WTP) for organic food products available in the Argentinean domestic market, with a view to providing some useful insights to gain support and outline strategies for promotion of organic production, marketing, regulation, and labelling programs of organic food products. A Binomial Multiple Logistic Regression model is estimated with data from a food consumption survey conducted in Buenos Aires city, Argentina, in April 2005. The Contingent Valuation Method was chosen in order to calculate their WTP for five organic selected products: Regular Milk, Leafy Vegetables, Whole Wheat Flour, Fresh Chicken and Aromatic Herbs. The empirical results reveal that consumers are willing to pay a premium for these products and that although prices play an important role, lack of store availability and of a reliable regulatory system to mitigate quality risks constraint consumption of organic products in this country.Willingness-to-pay, Food attributes, Organics, Demand and Price Analysis,

Willingness to pay for organic food in Argentina: Evidence from a consumer survey

Most food markets do not count on complete information about food quality for consumers. Quality has become a key concept in the new approaches of the Demand Theory (Lancaster, 1966; Antle, 1999), and, therefore, food quality information has turned into a crucial factor when explaining the existing differences between demand profiles. Throughout these last years, organic agriculture has undergone a notorious expansion due, among other things, to the greater interest shown by consumers aware of food safety concerns involving real or potential quality risks perceptions. (Henson, 1996) This paper aims to estimate consumers´ willingness to pay (WTP) for organic food products available in the Argentinean domestic market, with a view to providing useful evidence to the government, and thus gain support in the promotion of organic production, regulation processes and labelling programs. The Contingent Valuation Method (Hanemann, 1984) was selected to estimate WTP. Data derives from a food consumption survey conducted in Buenos Aires city in April 2005. The parameters estimates for the selected products were obtained by applying a Binomial Multiple Logistic Regression. The results indicate that Argentinean consumers are willing to pay a price premium to acquire better quality products. Indeed, this is conditioned by the effective prices in the domestic market, in which price premiums range from 6% to 200%, thereby restricting their acquisition. Besides, the scarce availability of these healthy products has also become another meaningful obstacle for domestic consumption expansion in Argentina.Willingness to pay, Food quality attributes, Organic price premium, Argentina., Food Consumption/Nutrition/Food Safety,

A new genus of neobatrachian frog from southern Patagonian forests, Argentina and Chile

In 1975 Lynch named a new species of frog based on two specimens from Puerto Eden, Wellington Island, southern Chile, tentatively allocated to the genus Telmatobius. Telmatobius grandisonae Lynch was later included by the same author in his genus Atelognathus. Based on a reappraisal of the type material and the description of the internal and external morphology, karyotype, tadpole morphology and molecular evidence from recently discovered specimens collected at Lago del Desierto, southern Argentina, we describe the monotypic genus Chaltenobatrachus, with Telmatobius grandisonae (Lynch) serving as the type species. Chaltenobatrachus differs from Atelognathus mainly in having a uniform bright green dorsal coloration, with brown to reddish warts; orange iris with gold spots; fingers with interdigital membrane; frontoparietals well developed, small nasals; well ossified sphenethmoid; anteriorly expanded homosternum; skin of tadpole transparent; oral disc with protruding anterior and lateral papillae; diploid number 2n = 32 chromosomes. The genetic distances between Chaltenobatrachus and Atelognathus meet or exceed most other intergeneric comparisons.Fil: Basso, Nestor Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Úbeda, Carmen A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Bunge, Maria M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Martinazzo Giménez, Liza Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentin

Looking ahead: anticipatory gaze and motor ability in infancy

The present study asks when infants are able to selectively anticipate the goals of observed actions, and how this ability relates to infants' own abilities to produce those specific actions. Using eye-tracking technology to measure on-line anticipation, 6-, 8- and 10-month-old infants and a control group of adults were tested while observing an adult reach with a whole hand grasp, a precision grasp or a closed fist towards one of two different sized objects. The same infants were also given a comparable action production task. All infants showed proactive gaze to the whole hand grasps, with increased degrees of proactivity in the older groups. Gaze proactivity to the precision grasps, however, was present from 8 months of age. Moreover, the infants' ability in performing precision grasping strongly predicted their ability in using the actor's hand shape cues to differentially anticipate the goal of the observed action, even when age was partialled out. The results are discussed in terms of the specificity of action anticipation, and the fine-grained relationship between action production and action perception