A Survey on q-Polynomials and their Orthogonality Properties

In this paper we study the orthogonality conditions satisfied by the classical q-orthogonal polynomials that are located at the top of the q-Hahn tableau (big q-jacobi polynomials (bqJ)) and the Nikiforov-Uvarov tableau (Askey-Wilson polynomials (AW)) for almost any complex value of the parameters and for all non-negative integers degrees. We state the degenerate version of Favard's theorem, which is one of the keys of the paper, that allow us to extend the orthogonality properties valid up to some integer degree N to Sobolev type orthogonality properties. We also present, following an analogous process that applied in [16], tables with the factorization and the discrete Sobolev-type orthogonality property for those families which satisfy a finite orthogonality property, i.e. it consists in sum of finite number of masspoints, such as q-Racah (qR), q-Hahn (qH), dual q-Hahn (dqH), and q-Krawtchouk polynomials (qK), among others. -- [16] R. S. Costas-Santos and J. F. Sanchez-Lara. Extensions of discrete classical orthogonal polynomials beyond the orthogonality. J. Comp. Appl. Math., 225(2) (2009), 440-451Comment: 3 Figures, 3 tables, in a 22 pages manuscrip

Centennial-scale vegetation and North Atlantic Oscillation changes during the Late Holocene in the southern Iberia

High-reso CE to lution pollen analysis, charcoal, non-pollen palynomorphs and magnetic susceptibility have been analyzed in the sediment record of a peat bog in Sierra Nevada in southern Iberia. The study of these proxies provided the reconstruction of vegetation, climate, fire and human activity of the last ∼4500 cal yr BP. A progressive trend towards aridification during the late Holocene is observed in this record. This trend is interrupted by millennial- and centennial-scale variability of relatively more humid and arid periods. Arid conditions are recorded between ∼4000 and 3100 cal yr BP, being characterized by a decline in arboreal pollen and with a spike in magnetic susceptibility. This is followed by a relatively humid period from ∼3100 to 1600 cal yr BP, coinciding partially with the Iberian-Roman Humid Period, and is indicated by the increase of Pinus and the decrease in xerophytic taxa. The last 1500 cal yr BP are characterized by several centennial-scale climatic oscillations. Generally arid conditions from ∼450 to 1300 CE, depicted by a decrease in Pinus and an increase in Artemisia, comprise the Dark Ages and the Medieval Climate Anomaly. Since ∼ 1300 to 1850 CE pronounced oscillations occur between relatively humid and arid conditions. Four periods depicted by relatively higher Pinus coinciding with the beginning and end of the Little Ice Age are interrupted by three arid events characterized by an increase in Artemisia. These alternating arid and humid shifts could be explained by centennial-scale changes in the North Atlantic Oscillation and solar activity

Hunting for CDF Multi-Muon "Ghost" Events at Collider and Fixed-Target Experiments

In 2008 the CDF collaboration discovered a large excess of events containing two or more muons, at least one of which seemed to have been produced outside the beam pipe. We investigate whether similar "ghost" events could (and should) have been seen in already completed experiments. The CDF di-muon data can be reproduced by a simple model where a relatively light X particle undergoes four-body decay. This model predicts a large number of ghost events in Fermilab fixed-target experiments E772, E789 and E866, applying the cuts optimized for analyses of Drell-Yan events. A correct description of events with more than two muons requires a more complicated model, where two X particles are produced from a very broad resonance Y. This model can be tested in fixed-target experiments only if the cut on the angles, or rapidities, of the muons can be relaxed. Either way, the UA1 experiment at the CERN ppbar collider should have observed O(100) ghost events.Comment: 15 pages, 9 figure

The semiclassical--Sobolev orthogonal polynomials: a general approach

We say that the polynomial sequence $(Q^{(\lambda)}_n)$ is a semiclassical Sobolev polynomial sequence when it is orthogonal with respect to the inner product $$_S= +\lambda <{{\bf u}}, {{\mathscr D}p \,{\mathscr D}r}>,$$ where ${\bf u}$ is a semiclassical linear functional, ${\mathscr D}$ is the differential, the difference or the $q$--difference operator, and $\lambda$ is a positive constant. In this paper we get algebraic and differential/difference properties for such polynomials as well as algebraic relations between them and the polynomial sequence orthogonal with respect to the semiclassical functional $\bf u$. The main goal of this article is to give a general approach to the study of the polynomials orthogonal with respect to the above nonstandard inner product regardless of the type of operator ${\mathscr D}$ considered. Finally, we illustrate our results by applying them to some known families of Sobolev orthogonal polynomials as well as to some new ones introduced in this paper for the first time.Comment: 23 pages, special issue dedicated to Professor Guillermo Lopez lagomasino on the occasion of his 60th birthday, accepted in Journal of Approximation Theor

Generating socially appropriate tutorial dialog

Analysis of student-tutor coaching dialogs suggest that good human tutors attend to and attempt to influence the motivational state of learners. Moreover, they are sensitive to the social face of the learner, and seek to mitigate the potential face threat of their comments. This paper describes a dialog generator for pedagogical agents that takes motivation and face threat factors into account. This enables the agent to interact with learners in a socially appropriate fashion, and foster intrinsic motivation on the part of the learner, which in turn may lead to more positive learner affective states

Abelian Toda field theories on the noncommutative plane

Generalizations of GL(n) abelian Toda and $\widetilde{GL}(n)$ abelian affine Toda field theories to the noncommutative plane are constructed. Our proposal relies on the noncommutative extension of a zero-curvature condition satisfied by algebra-valued gauge potentials dependent on the fields. This condition can be expressed as noncommutative Leznov-Saveliev equations which make possible to define the noncommutative generalizations as systems of second order differential equations, with an infinite chain of conserved currents. The actions corresponding to these field theories are also provided. The special cases of GL(2) Liouville and $\widetilde{GL}(2)$ sinh/sine-Gordon are explicitly studied. It is also shown that from the noncommutative (anti-)self-dual Yang-Mills equations in four dimensions it is possible to obtain by dimensional reduction the equations of motion of the two-dimensional models constructed. This fact supports the validity of the noncommutative version of the Ward conjecture. The relation of our proposal to previous versions of some specific Toda field theories reported in the literature is presented as well.Comment: v3 30 pages, changes in the text, new sections included and references adde

Evaluation of the awareness of a cohort of veterinary students from various Spanish universities in regards to the illegal trade of exotic animal species

Resúmenes IV Congreso VetDoc de Docencia Veterinaria, León 2017 (6-7 de Julio)[ES] El comercio ilegal de animales exóticos incluye las siguientes actividades: caza furtiva, captura de especies y posterior venta ilícita y venta de subproductos animales (cuernos, piel, marfil, etc.) (South y Wyatt, 2011). Este comercio tiene un enorme impacto en las poblaciones de diferentes especies, tanto en sus lugares de origen como en el destino, debido al riesgo de introducción de especies exóticas y posterior daño a la flora y fauna (Nentwig, 2009)

Social Network Analysis: Recent Achievements and Current Controversies

Network analysis has grown rapidly over the past two decades, but criticisms of the approach have increased as well This article focuses on several accomplishments and unresolved problems of the network approach In the first section. I illustrate the value of the network model in several substantive areas. focusing on studies of centrahty and power, network subgroups, and interorganizational relations I then discuss three issues over which the approach has provoked controversy the relation between network analysis and rational choice theory; the role of norms and culture, and the question of human agency I conclude with some examples of how network theorists are addressing these problemsPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68023/2/10.1177_000169939403700403.pd

Knowledge, attitudes and preventive practices of primary health care professionals towards alcohol use: A national, cross-sectional study

Introduction Primary care (PC) professionals' knowledge about alcohol use has been identified as one of the barriers PC providers face in their clinic. Both PC professionals' level of training and attitude are crucial in the clinical practice regarding alcohol use. Objective To evaluate the knowledge, attitude, and preventive practices of Spanish PC physicians and nurses towards alcohol use. Design An observational, descriptive, cross-sectional, multi-center study. Methodology Location: PC centers of the Spanish National Health System (NHS). Participants: PC physicians and nurses selected randomly from health care centers, and by sending an e-mail to semFYC and SEMERGEN members. Healthcare providers completed an online survey on knowledge, attitude, and follow-up recommendations for reducing alcohol intake. A descriptive, bivariate, and multivariate statistical analysis was conducted (p<0.05). Results Participants: 1, 760 healthcare providers completed the survey (75.6% [95% CI 73.5-77.6] family physicians; 11.4% [95% CI 9.9-12.9] medical residents; and 12.5% [95% CI 10.9-14.1] nurses), with a mean age of 44.7 (SD 11.24, range: 26-64, 95% CI: 47.2-48.2). Knowledge was higher in family physicians (p<0.001), older professionals (Spearman's r = 0.11, p<0.001), and resident trainers (p<0.001). The PC professional most likely to provide advice for reducing alcohol use was: a nurse (p<0.001), female (p = 0.010), between 46 and 55 years old (p <0.001). Conclusions PC providers' knowledge and preventive practices regarding alcohol use are scarce, hence specific training strategies to increase their knowledge and improve their attitude and skills with regard to this health problem should be considered a healthcare policy priority