An estimation of residential water demand using co-integration and error correction tec hniques

In this paper short- and long-run price elasticities of residential water demand are estimated using co-integration and error-correction methods. Unit root tests reveal that water use series and series of other variables affecting use are non-stationary. However, a long-run co-integrating relationship is found in the water demand model, which makes it possible to obtain a partial correction term and to estimate an error correction model. Using monthly time-series observations from Seville, Spain, we find that the price-elasticity of demand is estimated as around -0.1 in the short run and -0.5 in the long run. These results are robust to the use of different specifications.

Pobreza, degradación ambiental y liberalización del comercio: Hacia una intervención de políticas «second best»

[EN] Forest based agricultural systems in the tropics are being opened up to international trade at an unprecedented rate.This is the case of tropical agriculture in Mexico under the North American Free Trade Agreement (NAFTA), which is also having significant impacts on the decentralized land use decisions of small-scale farmers and on the natural resource base on which they depend. This paper develops a bioeconomic model of a typical forest-land based farming system that is integrated with the non-farm labour sector, as typically found in tropical regions. The data used to generate the simulations were gathered in two communities of Yucatan (Mexico) in 1998-2000. Through a systemdynamics framework, the agro-ecological and farming economic subsystems are integrated and the current situation of price liberalization that is negatively affecting soil capital and income levels is compared to a scenario that precludes an «optimal path to extinction» through careful policy intervention. This second-best case is based on a targeted policy mix that seeks to maintain the system viable for as long as possible above an irreducible poverty level. The policy intervention involves, simultaneoulsy, subsidizing off-farm wage rates, intensification of land use, and the control of households’ rights to the forest commons. The model shows that such policy intervention can result in a large positive discounted net payoff basedon the increased incomes for the farming community after deducting the implementation costs of such intervention.[ES] Los sistemas agro-forestales tropicales están siendo expuestos al comercio internacional a un ritmo sin precedentes. Este es el caso de la agricultura en México en el contexto del Tratado de Libre Comercio de América del Norte (TLCAN) que está teniendo impactos importantes sobre las decisiones descentralizadas de los campesinos y la base de los recursos naturales del cual dependen. El presente artículo desarrolla un modelo bio-económico basado en un típico sistema agro-forestal del trópico que, a su vez, se encuentra integrado con el sector laboral no-agrícola. Los datos empleados para generar las simulaciones han sido obtenidos en dos comunidades campesinas de Yucatán (México) entre los años 1998-2000. Mediante un marco teórico dinámico se integran el subsistema de producción campesina y el agroecológico. El objetivo es poder comparar la situación actual, con políticas macroeconómicas de liberalización de precios agrícolas (p.ej., maíz) que están afectando negativamente tanto el capital natural y el nivel de renta de los hogares campesinos, con un posible escenario basado en intervenciones de política económica con el objetivo de evitar una posible «senda óptima de extinción» del capital natural. Se trata de poner en práctica de forma simultánea varias políticas «second-best» manteniendo viable el sistema productivo durante el mayor tiempo posible y manteniendo, a su vez, los hogares por encima del umbral de pobreza. La integración de varias políticas implica (a) intervenir los salarios nominales fuera de la agricultura, (b) la intensificación del uso de la tierra, y (c) el control de los derechos de propiedad de los hogares sobre la tierra comunal. El modelo demuestra que este tipo de intervención «second best» es rentable si se tienen en cuenta la renta generada por las comunidades campesinas y el coste de la puesta en práctica de dichas políticas.Pascual, U.; Martínez-Espiñeira, R. (2006). Poverty and environmental degradation under trade liberalization: Searching for second-best policy options. Economía Agraria y Recursos Naturales - Agricultural and Resource Economics. 6(12):121-144. doi:10.7201/earn.2006.12.06SWORD12114461

Effect on Recreation Benefit Estimates from Correcting for On-Site Sampling Biases and Heterogeneous Trip Overdispersion in Count Data Recreation Demand Models (STATA)

Correction procedures (STATA commands NBSTRAT and GNBSTRAT) are applied to simultaneously account for zero-truncation, endogenous stratification, and overdispersion, and also consider heterogeneity in the overdispersion parameter. Their effect is shown on welfare estimates from previous studies, confirming that the routines perform the appropriate correction and only when endogenous stratification is expected

MAGIC and H.E.S.S. detect VHE gamma rays from the blazar OT081 for the first time: a deep multiwavelength study

https://pos.sissa.it/395/815/pdfPublished versio

Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign

Abstract: In 2017, the Event Horizon Telescope (EHT) Collaboration succeeded in capturing the first direct image of the center of the M87 galaxy. The asymmetric ring morphology and size are consistent with theoretical expectations for a weakly accreting supermassive black hole of mass ∼6.5 × 109 M ⊙. The EHTC also partnered with several international facilities in space and on the ground, to arrange an extensive, quasi-simultaneous multi-wavelength campaign. This Letter presents the results and analysis of this campaign, as well as the multi-wavelength data as a legacy data repository. We captured M87 in a historically low state, and the core flux dominates over HST-1 at high energies, making it possible to combine core flux constraints with the more spatially precise very long baseline interferometry data. We present the most complete simultaneous multi-wavelength spectrum of the active nucleus to date, and discuss the complexity and caveats of combining data from different spatial scales into one broadband spectrum. We apply two heuristic, isotropic leptonic single-zone models to provide insight into the basic source properties, but conclude that a structured jet is necessary to explain M87’s spectrum. We can exclude that the simultaneous γ-ray emission is produced via inverse Compton emission in the same region producing the EHT mm-band emission, and further conclude that the γ-rays can only be produced in the inner jets (inward of HST-1) if there are strongly particle-dominated regions. Direct synchrotron emission from accelerated protons and secondaries cannot yet be excluded

Correcting for the endogeneity of pro-environment behavioral choices in contingent valuation

In contingent valuation studies, observed behavioral choices often enter as independent variables in the willingness to pay function. However, these variables may be endogenously determined when the error term in the behavioral model is correlated with the error term in the willingness to pay model. We investigate the effects of correcting for the endogeneity of a variable, namely membership status in environmental organizations that proxies unobservable characteristics of the respondents. Jointly modeling the membership variable and the willingness to pay response yields an estimate for the effect of the former that contradicts previous findings but is intuitive and agrees with theoretical expectations.Contingent valuation Environmental attitudes Bivariate probit Endogeneity Whales

Is the Pricing of Urban Water Services Justifiably Perceived as Unequal among Spanish Cities?

International audienceDecentralized decision making and lack of regulation lead to the existence of significant differences in the price of water for residential uses among Spanish cities. Why do these differences persist? Do they have to do with cost differentials or do they result from political and business interests? Can users perceive water tariffs as fair or is there unfairness among citizens when it comes to the access to water? We find that some of the differences are due to arbitrary decisions made by policy and business decision makers, so it is recommended that a regulation be adopted that sets criteria for guidance in tariff design, especially for lower levels of consumption within which water is considered a merit good

Responses to changes in domestic water tariff structures: a latent class analysis on household-level data from Granada, Spain

A problem that affects the estimation of water demand functions is the presence of unobserved individual heterogeneity, which means that a common demand function is unlikely to represent the behavior of all users. We implement Latent Class Models to estimate water demand functions for four groups of users who are classified according to their unobservable preferences. This more flexible approach makes it possible to distinguish four different response patterns to changes in the drivers of water use, including different price elasticities. These results should be of particular interest to regulators who would like to tailor water demand management policy to heterogeneous users. Our analysis exploits household-level panel data on residential water demand and consumers’ characteristics obtained by combining information from a survey of 1,465 domestic users in the city of Granada and bimonthly price and consumption data supplied by this city’s water supplier from the period 2009–2011.L'estimation des fonctions de demande d'eau est affectée par la présence d'hétérogénéité individuelle non-observable, qui fait qu'une fonction de demande commune ne va pas représenter de manière fiable le comportement de tous les usagers. Les auteurs développent un modèle en classes latentes pour estimer les fonctions de demande d'eau de quatre groupes d'usagers classés en fonction de préférences non-observables. Cette approche plus flexible permet de distinguer quatre types de réponses aux changements dans les déterminants de l'usage de l'eau, y compris des élasticités-prix différentes. Ces résultats sont particulièrement utiles aux régulateurs qui souhaiteraient ajuster leurs politiques de gestion de la demande d'eau en présence d'usagers hétérogènes. Cette analyse exploite des données en panel au niveau des ménages sur la demande en eau et les caractéristiques des consommateurs en combinant une enquête de 1 465 foyers de la ville de Grenade ainsi que des données bimensuelles de prix et de consommation fournies par le fournisseur des eaux de la ville sur la période 2009-2011

Does private management of water supply services really increase prices? An empirical analysis

In this paper we try to explain differences in the average price of domestic water supply services in Spain, paying special attention to the effects of privatisation of the service on price levels. We base our empirical analysis on the application of a `treatment effects' model on a sample of 53 major urban municipalities. This model accounts for the fact that municipalities do not randomly assign themselves between a group using strictly public ownership and management and a group where all or part of the service has been delegated to a private firm. We find that, once this endogeneity is taken into account, there seems to be a positive and significant effect of privatisation on water price levels