On the Evaluation and Comparison of Taggers: The Effect of Noise in Testing Corpora

This paper addresses the issue of {\sc pos} tagger evaluation. Such evaluation is usually performed by comparing the tagger output with a reference test corpus, which is assumed to be error-free. Currently used corpora contain noise which causes the obtained performance to be a distortion of the real value. We analyze to what extent this distortion may invalidate the comparison between taggers or the measure of the improvement given by a new system. The main conclusion is that a more rigorous testing experimentation setting/designing is needed to reliably evaluate and compare tagger accuracies.Comment: Appears in proceedings of joint COLING-ACL 1998, Montreal, Canad

Mapping WordNets Using Structural Information

We present a robust approach for linking already existing lexical/semantic hierarchies. We used a constraint satisfaction algorithm (relaxation labeling) to select --among a set of candidates-- the node in a target taxonomy that bests matches each node in a source taxonomy. In particular, we use it to map the nominal part of WordNet 1.5 onto WordNet 1.6, with a very high precision and a very low remaining ambiguity.Comment: 8 pages, uses epsfig. To appear in ACL'2000 proceeding

Exploration of the nutritional profile of Trichocereus terscheckii (Parmentier) Britton & Rose stems

Columnar cacti Trichocereus terscheckii is an important source of food and water for insects, birds and wild cattle in dry areas of North West Argentina. Their fruits have been suggested as a plausible source of food, but are not directly included in the human diet yet. Stem chemistry has long been of interest because of its hallucinogenic properties, but little is known about the nutritional value. In this work, basic nutritional composition of a mature stem was analyzed establishing moisture, total fat, ash, fiber, protein, lipidic and sugar profile. The main constituents fatty acid found in T. terscheckii were linolenic, linoleic, palmitic and oleic acids, but also a rare isomer of oleic acid was relatively abundant. This pattern did not agree with the profiles found in other species of columnar cacti. Current exploration of nutritional profiles of T. terscheckii stem provides novel information that contributes to a better understanding of this species whose slow development rate, high water storage capacity and hallucinogenic properties are features that make it especially vulnerable to an increased rate of extraction, habitat fragmentation and extensive cattle ranching.El cactus columnar Trichocereus terscheckii constituye una importante fuente de agua y alimento de insectos, aves y ganado salvaje en áreas áridas del noroeste argentino. Se ha sugerido la posibilidad de que sus frutos sean una fuente de alimento, pero hasta el momento no ha sido incluido en la dieta humana de manera generalizada. Por otro lado, la química de los tallos ha sido largamente de interés por sus propiedades alucinógenas y sin embargo poco se conoce de sus valores nutricionales. En el presente trabajo se ha analizado la composición nutricional básica de un tallo maduro estableciendo su humedad, contenido graso, de ceniza, fibra, proteína total y sus perfiles lipídicos y de azúcares. Los principales ácidos grasos constitutivos de T. terscheckii fueron el linolénico, linoleico, palmítico y oleico; sin embargo también se encontró en relativa abundancia un raro isómero del ácido oleico. Este patrón lipídico no coincide con los perfiles reportados en otras especies de cactus columnares. De esta manera, se presenta información novedosa sobre el perfil nutricional del tallo de T. terscheckii con el fin de contribuir a una mejor comprensión de esta especie, cuyas características (lento desarrollo, gran capacidad de almacenamiento de agua y propiedades alucinógenas) la hacen especialmente vulnerable a elevadas tasas de extracción, fragmentación del hábitat y la ganadería extensiva.Fil: Padro, Julian. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Soto, Ignacio Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentin

Effects of Orientations, Aspect Ratios, Pavement Materials and Vegetation Elements on Thermal Stress inside Typical Urban Canyons

The analysis of local climate conditions to test artificial urban boundaries and related climate hazards through modelling tools should become a common practice to inform public authorities about the benefits of planning alternatives. Different finishing materials and sheltering objects within urban canyons (UCs) can be tested, predicted and compared through quantitative and qualitative understanding of the relationships between the microclimatic environment and subjective thermal assessment. This process can work as support planning instrument in the early design phases as has been done in this study that aims to analyze the thermal stress within typical UCs of Bilbao (Spain) in summertime through the evaluation of Physiologically Equivalent Temperature using ENVI-met. The UCs are characterized by different orientations, height-to-width aspect ratios, pavement materials, trees’ dimensions and planting pattern. Firstly, the current situation was analyzed; secondly, the effects of asphalt and red brick stones as streets’ pavement materials were compared; thirdly, the benefits of vegetation elements were tested. The analysis demonstrated that orientation and aspect ratio strongly affect the magnitude and duration of the thermal peaks at pedestrian level; while the vegetation elements improve the thermal comfort up to two thermophysiological assessment classes. The outcomes of this study, were transferred and visualized into green planning recommendations for new and consolidated urban areas in Bilbao.The work leading to these results has received funding from COST Action TU0902, the European Community’s Seventh Framework Programme under Grant Agreement No. 308497, Project RAMSES—Reconciling Adaptation, Mitigation and Sustainable Development for Cities (2012–2017) and Diputación Foral de Bizkaia Exp. 6-12-TK-2010-0027, Project SICURB-ITS- Desarrollo de Sistemas para el análisis de la Contaminación atmosférica en zonas URBanas integrados en ITS (2010–2011)

Presence of 3d Quadrupole Moment in LaTiO3 Studied by 47,49Ti NMR

Ti NMR spectra of LaTiO3 are reexamined and the orbital state of this compound is discussed. The NMR spectra of LaTiO3 taken at 1.5 K under zero external field indicate a large nuclear quadrupole splitting. This splitting is ascribed to the presence of the rather large quadrupole moment of 3d electrons at Ti sites, suggesting that the orbital liquid model proposed for LaTiO3 is inappropriate. The NMR spectra are well explained by the orbital ordering model expressed approximately as $1/\sqrt{3}(d_{xy}+d_{yz}+d_{zx})$ originating from a crystal field effect. It is also shown that most of the orbital moment is quenched.Comment: 4 pages, 3 fugures; to appear in Phys. Rev. Let

Decentralization and regional economic disparities

This paper analyses the impact of both fiscal and political decentralisation on regional productivity inequalities. The study of the influence of decentralisation on economic growth has received some attention in recent years, but very few studies deal with its impact on regional inequalities, both theoretically and empirically. In this paper, we analyse the relationship between different measures of regional inequalities in productivity, and several measures of political and fiscal decentralisation for a sample of 15 OECD countries. In order to control for other possible influences, we have also include in the analysis measures of public sector size and the type of party government. The results suggest a strong negative correlation between decentralisation, mainly fiscal decentralisation, and regional inequalities. Of course, much more analysis must be done before we can demonstrate such relationship. We hope that this paper will stimulate further research.

Mobility and regional inequality in the European Union: Implications for economic policy

The aim of this paper is to analyse the mobility of per capita income distribution in the European regions during the period 1977-1996. In doing so we will attempt highlight some aspects of the nature of interregional inequality. We also hope to draw inferences that might be applied by European regional policy makers. If, for example, there proves to be very little mobility, this might mean that the regional positions are consolidated. If this were the case, a belligerent regional policy could be introduced in order to reduce regional disparities. If, on the other hand, our results suggest that income variability accounts for most of the disparities, regional policy could be focused on the negative effects of economic cycles. In this case, a regional convergence policy might be made to take second place. Our methodological approach involves calculating indices commonly used in the dynamic income distribution literature, such as those of Theil, Atkinson and Shorrocks. These indices are calculated at different levels, both temporal and geographical, in order to discover different regional behaviour patterns throughout the study period.