A semi-infinite matrix analysis of the BFKL equation

The forward BFKL equation is discretised in virtuality space and it is shown that the diffusion into infrared and ultraviolet momenta can be understood in terms of a semi-infinite matrix. The square truncation of this matrix can be exponentiated leading to asymptotic eigenstates sharing many features with the BFKL gluon Green's function in the limit of large matrix size. This truncation is closely related to a representation of the XXX Heisenberg spin $= - \frac{1}{2}$ chain with SL(2) invariance where the Hamiltonian acts on a symmetric double copy of the harmonic oscillator. A simple modification of the BFKL matrix suppressing the infrared modes generates evolution with energy compatible with unitarity.Comment: Small changes, same conclusions, matching the published version in EPJ

Ordering our world: the quest for traces of temporal organization in autobiographical memory

An experiment examined the idea, derived from the Self Memory System model (Conway & Pleydell-Pearce, 2000), that autobiographical events are sometimes tagged in memory with labels reflecting the life era in which an event occurred. The presence of such labels should affect the ease of judgments of the order in which life events occurred. Accordingly, 39 participants judged the order of two autobiographical events. Latency data consistently showed that between-era judgments were faster than within-era judgments, when the eras were defined in terms of either: (a) college versus high school, (b) academic quarter within year, or (c) academic year within school. The accuracy data similarly supported the presence of a between-era judgment effect for the college versus high school dichotomy

The segmentation of the Canarian tourism market with regared to expenditure: an empirical study of La Palma

In the context of the European Union countries, the Canary Islands have presented and continue to do so, unquestionable comparative and competitive advantages as supplier of tourism products that have lead to, driven more by managerial initiative and foreign capital than by the desire and initiative of the local population, a truly monocultural tourism production. The strong expansion of the services sector that tourism development has produced in parallel constitutes a logical consequence of an activity such as tourism characterised to be basic (Begg, 1993), that is to say, to present very strong effects on other economic activities. It is in fact the economic importance of tourism in the Canary Islands that has lead local authorities to consider the maintenance and improvement of competitiveness levels in tourism in the field of the domestic and international market (Government of Canaries, 1998). The maintenance and improvement of competitiveness levels depend on the segmentation of tourism supply as means of responding to, on one hand, greater competition in prices in the tourist markets of homogeneous products, especially in the sector of sun and beach, and on the other hand, the appearance of an increasing demand for more customised services, where the tourist outlines his/her leisure time requirements in an individual way which ultimately changes the essence of the homogeneous tourist package that the tour-operator has traditionally offered. In this paper we use, therefore, a focus on the segmented markets in which a range of tourism products exists, each one of which satisfies, to greater or lesser extent, the needs of a segment of demand. We have two objectives, firstly, to identify those segments of current demand acquired at destination and, secondly, to determine, amongst them the niches associated with greater expense, in order to profile lines of a regional policy of innovation in products that it embraces them and generates greater levels of local development. Thus we will analyse several sources of data. On the one hand, data which comes from the Survey of Tourist Expenditure carried out by the Institute of Statistics of the Canary Islands and on the other, information obtained in an empirical study carried out over the last few years and referring especially to the island of La Palma. Specifically, we will establish two expenditure segments: lower and middle, to thus determine the characteristics that identify tourists included in the bracket of highest expenditure at destination

Infección por toxocara en una población infantil

La toxocariosis es una zoonosis parasitaria de alta prevalencia en las poblaciones infantiles. Sus manifestaciones clínicas son muy variadas pudiendo cursar asintomáticamente o presentar un fuerte compromiso visceral u ocular. El objetivo de este trabajo fue determinar la seroprevalencia de anticuerpos antitoxocara en una población infantil no determinada por la sospecha clínica de infección por parásitos del género Toxocara.Facultad de Ciencias Veterinaria

Infección por toxocara en una población infantil

La toxocariosis es una zoonosis parasitaria de alta prevalencia en las poblaciones infantiles. Sus manifestaciones clínicas son muy variadas pudiendo cursar asintomáticamente o presentar un fuerte compromiso visceral u ocular. El objetivo de este trabajo fue determinar la seroprevalencia de anticuerpos antitoxocara en una población infantil no determinada por la sospecha clínica de infección por parásitos del género Toxocara.Facultad de Ciencias Veterinaria

Infección por toxocara en una población infantil

La toxocariosis es una zoonosis parasitaria de alta prevalencia en las poblaciones infantiles. Sus manifestaciones clínicas son muy variadas pudiendo cursar asintomáticamente o presentar un fuerte compromiso visceral u ocular. El objetivo de este trabajo fue determinar la seroprevalencia de anticuerpos antitoxocara en una población infantil no determinada por la sospecha clínica de infección por parásitos del género Toxocara.Facultad de Ciencias Veterinaria

The Fight against Malaria: A New Index for Quantifying and Assessing Policy Implementation Actions to Reduce Mortality in Sub-Saharan Africa

More than 90% of people suffering from Malaria live in Sub-Saharan Africa (SSA). We construct, for the first time, a Malaria Policy Index (MaPI) for 44 SSA countries to quantify and compare each country’s antimalarial policy actions between 1990 and 2017. The MaPI compiles information on intervention strategies such as prevention, diagnosis and treatment (Pillar 1) and the use of antimalarial therapies and tests (Pillar 2). We find that: antimalarial policy implementation is a widespread phenomenon in the region from the mid-2000s on; initial differences in per capita GDP, quality of institutions and malaria burden are not associated with the current levels of policy implementation and; there exists a first stage of policy divergence (before mid-2000s), followed by a strong convergence period. The convergence period is associated with an unprecedented increase in international malaria fight funding, which was unevenly distributed across countries according to their necessities to eradicate the disease. Using a difference-in-difference events study design and a distributed lag model approach, we estimate the effect of antimalarial policy implementation increases on subsequent changes in malaria mortality within SSA countries. We find that policies included in Pillar 1 are key to reduce within-country malaria mortality: an increase of 10 p.p. in policies implemented in this pillar generates a cumulative malaria mortality decrease of about 6 p.p. after five years

Simulación estocástica de un brote de enfermedad respiratoria aviar en Camagüey

Background: One of the reasons to study infectious diseases is to increase their control and eradication. Mathematical models could be a powerful tool to achieve that end, which allows for optimization of limited resources, and conduct more effective measures; these models are made to predict and increase understanding of the studied phenomenon. The aim of this paper is to conduct simulations using the stochastic model known as Susceptible, Infected, Recovered (SIR), and introduce them in the curricula of students, epizootiological analyses, and decision-making. Methods: Virtually the entrance of ten migrating birds with respiratory processes was simulated on bird rearing farms averaging 5000 free-range poultry from different types. The R0 was determined depending on the incidence. Results: Simulation was run with a low communicability index (1.8 %), that is, 1.8 out of every 100 birds get sick, after interacting with other 5 birds each, at random, for 10 days. In the absence of intervention, there would be a spike of sick animals at 20 days, surpassing 3000 birds. A basic reproductive number greater than the unit (R0=1.14) was observed, thus qualifying as an epidemic outbreak. Conclusions: A number of simulations were made using the stochastic model with a sustainable analytical tool based on an R-free program. The need to integrate the epizootiology, epidemiology, and mathematic was demonstrated, suggesting that appropriate training should be provided by competent professionals. Key words:  epidemiology, prevention, and control, transmission, veterinary (Source: MeSH)Antecedentes: Una de las razones para estudiar las enfermedades infecciosas es el incremento del control y erradicación de las mismas. Los modelos matemáticos pueden ser una herramienta poderosa para este fin, permitiendo optimizar los recursos limitados y dirigir medidas más efectivas; se utilizan para la predicción y comprensión del fenómeno en estudio. Objetivo. Realizar simulaciones con el modelo estocástico Susceptible, Infectado, Recuperado (SIR) para introducirlos en la docencia, en los análisis epizootiológicos y en la toma de decisiones. Métodos: Se simuló de manera virtual con un modelo estocástico la entrada de diez aves migratorias enfermas de procesos respiratorios en fincas de criadores, donde hay como promedio un total de 5000 aves de corral de diferentes tipos. Se determinó R0 (número reproductivo básico) de acuerdo a la incidencia. Resultados: La simulación se corrió con un índice de transmisibilidad bajo (1,8 %) y cada ave contacta un promedio de cinco aves de manera aleatoria durante 10 días. De no hacer ninguna intervención habría a los 20 días un pico de enfermos que sobrepasaría los 3000. Se encontró un número reproductivo básico mayor que la unidad (R0=1,14) por lo que califica como brote epidémico. Conclusiones: Se realizaron simulaciones con el modelo estocástico con una herramienta analítica sustentable basada en el programa libre R. Se constató la necesidad de integrar la epizootiología, la epidemiologia y la matemática; por lo que deben entrenarse en estos aspectos a los estudiantes relacionados con la salud animal y la salud pública. Palabras clave: epidemiología, prevención y control, trasmisión, veterinaria (Fuente: MeSH