Shape Outlier Detection and Visualization for Functional Data: the Outliergram

We propose a new method to visualize and detect shape outliers in samples of curves. In functional data analysis we observe curves defined over a given real interval and shape outliers are those curves that exhibit a different shape from the rest of the sample. Whereas magnitude outliers, that is, curves that exhibit atypically high or low values at some points or across the whole interval, are in general easy to identify, shape outliers are often masked among the rest of the curves and thus difficult to detect. In this article we exploit the relation between two depths for functional data to help visualizing curves in terms of shape and to develop an algorithm for shape outlier detection. We illustrate the use of the visualization tool, the outliergram, through several examples and asses the performance of the algorithm on a simulation study. We apply them to the detection of outliers in a children growth dataset in which the girls sample is contaminated with boys curves and viceversa.Comment: 27 pages, 5 figure

Socio-Economic Determinants Of Abortion Rates

Abortion rates are increasing all around the world, especially for young women. Our proposals for public policies to reduce unwanted pregnancies are based on an analysis of the socio-economic determinants of abortion rates. Special attention is paid to regional levels of alcohol consumption, living conditions, and public spending on health and education. We carry out estimations using data on regions in Spain from 1999 to 2004. There is empirical evidence that socioeconomic conditions, lifestyles and regional characteristics determine regional abortion rates. Our results suggest that it is important to design public policies to reduce alcohol abuse, improve citizens’ working conditions and promote gender equality through government subsidized childcare.abortion rates; unplanned pregnancy; public policies.

Are Drinkers Prone To Engage In Risky Sexual Behaviors?

Sexually transmitted diseases pose an important public health problem around the world. Although many studies have explored the link between alcohol use and risky sexual practices, the unobserved differences among individuals make it difficult to assess whether the associations are casual in nature. In order to overcome these difficulties, we have obtained data from the Spanish Health and Sexual Behavior Survey (2003) in order to analyze risky sexual behaviors using four alternative methodologies: controlling results with a rich set of variables; identifying the impact of alcohol use while assuming there is an identical selection outcome for observed and unobserved variables; estimating alcohol consumption and risky sexual behaviors simultaneously based on instrumental variables; and using reduced-form equations to analyze the impact of alcohol prices and other alcohol policies on the likelihood of risky intercourse. We provide empirical evidence that alcohol abuse might increase the probability of risky sex and, more importantly, different alcohol policies are not only effective tools for reducing alcohol demand but also for controlling risky sexual behaviors.alcohol; sexually transmitted diseases; unobserved individual heterogeneity.

A new way of teaching different subjects in a foreign language in the Building Engineering Degree at the Universidad Politécnica.

The European Union has been promoting linguistic diversity for many years as one of its main educational goals. This is an element that facilitates student mobility and student exchanges between different universities and countries and enriches the education of young undergraduates. In particular, a higher degree of competence in the English language is becoming essential for engineers, architects and researchers in general, as English has become the lingua franca that opens up horizons to internationalisation and the transfer of knowledge in today’s world. Many experts point to the Integrated Approach to Contents and Foreign Languages System as being an option that has certain benefits over the traditional method of teaching a second language that is exclusively based on specific subjects. This system advocates teaching the different subjects in the syllabus in a language other than one’s mother tongue, without prioritising knowledge of the language over the subject. This was the idea that in the 2009/10 academic year gave rise to the Second Language Integration Programme (SLI Programme) at the Escuela Arquitectura Técnica in the Universidad Politécnica Madrid (EUATM-UPM), just at the beginning of the tuition of the new Building Engineering Degree, which had been adapted to the European Higher Education Area (EHEA) model. This programme is an interdisciplinary initiative for the set of subjects taught during the semester and is coordinated through the Assistant Director Office for Educational Innovation. The SLI Programme has a dual goal; to familiarise students with the specific English terminology of the subject being taught, and at the same time improve their communication skills in English. A total of thirty lecturers are taking part in the teaching of eleven first year subjects and twelve in the second year, with around 120 students who have voluntarily enrolled in a special group in each semester. During the 2010/2011 academic year the degree of acceptance and the results of the SLI Programme have been monitored. Tools have been designed to aid interdisciplinary coordination and to analyse satisfaction, such as coordination records and surveys. The results currently available refer to the first and second year and are divided into specific aspects of the different subjects involved and into general aspects of the ongoing experience

Consequences of BSE on Consumers' Attitudes, Perceptions and Willingness to Pay for Certified Beef in Spain

The BSE crisis has increased consumers' concerns on beef safety. Product quality systems and controls have been reinforced. Traceability certification and quality labels have been developed to communicate consumers the safety characteristics of the labelled beef and recover consumption. As a consequence, production costs have increased, which have been ultimately transmitted to consumer prices. The objective of this paper is to develop a conceptual model able to analyse main factors influencing consumers' willingness-to-pay for certified beef. A three-equation recursive model is jointly estimated. Results indicate that income, level of beef consumption, the average price consumers paid for beef and beef safety perception are main determinants of Spanish consumers' willingness- to-pay for certified beef.Certified beef, willingness-to-pay, attitudes, food safety, Consumer/Household Economics, Food Consumption/Nutrition/Food Safety,

Price transmission analysis: A flexible methodological approach applied to European hog markets

The study of spatial price relationships contributes to explain markets performance, their degree of integration or isolation, and the speed at which information is transmitted. A great deal of methods have been used to analyze this issue, being the most important: causality tests, impulse- response functions and cointegration. Normally, these techniques have been individually applied. However, a more rich knowledge of the functioning of markets can be extracted when they are jointly applied. In this paper, we try to conjugate these three techniques in a common econometric model. First, Johansen(1988) multivariate cointegration tests are used to determine the number of long-run equilibrium relationships. Cointegration is considered not only as informative about long-run price transmission but also as an essential step in the correct specification of a vector error correction model (VECM) used in the subsequent analysis. Second, Dolado and Lutkepohl(1996) causality tests are used to investigate the lead-lag behaviour among markets. Finally, impulse-response functions are calculated from the VECM estimated in the first stage for evaluating dynamic price linkages. The method exposed is applied to study spatial pork prices relationships among seven countries in the EU from 1988 to 1995. Weekly prices at farm level published by EUROSTAT: "Agricultural Markets" are used.

Spanish Consumers' Attitudes and Acceptability towards GM Food Products

The objective of this paper is to analyse consumers’ attitudes and acceptability of GM food products in Spain. From the methodological point of view, a three-equation model of consumer behaviour is estimated assuming a kind of causal chain among the degree of knowledge, attitudes and buying intentions. Explanatory variables include socioeconomic characteristics of respondents as well as endogenous variables of the previous equations. The model provides a better knowledge of how attitudes and buying intentions towards GM food are formed. Higher educated consumers, more concerned about labelling information and less about price, and regular buyers of organic foods show a higher (not necessarily better) knowledge on GM technology and its consequences. However, those consumers with a lower level of knowledge, together with those who are not concerned about safety, are not used to recycle but to purchase fast food generate more positive attitudes towards GMs, which finally determine future purchasing intention.GM foods, Spain, consumers' attitudes, econometric model,

New pedagogic trends towards the evaluation of educators

Un informe de la Organización para la Cooperación y el Desarrollo Económico (OCDE) considera España uno de los países avanzados donde los profesores no se evalúan con regularidad. Este informe se ha hecho eco en los medios de comunicación generando un gran debate en la comunidad educativa. Tratando de arrojar luz sobre este asunto, en este artículo se analiza si la evaluación del profesorado es o debería ser una prioridad en los centros docentes.A report from the Organisation for Economic Co-operation and Development (OECD) names Spain as one of the advanced countries, where public teachers are not evaluated regularly. This report has been a matter of discussion in the media generating an intense debate in the educational community. With the intention of shedding light on this issue, whether the evaluation of teachers is or ought to be a priority will be analised in this article