Aproximación lineal por tramos a comportamientos no lineales: estimación de señales de nivel de crecimiento

En este trabajo se propone una señal del nivel y del crecimiento tendencial de una variable económica, cuando ésta ha pasado por un período temporal específico en que determinados aconteeimientos especiales han truncado su tendencia. Para ello se analizan las consecuencias de emplear modelos univariantes no lineales, así como análisis de intervención. En el supuesto de ruptura estocástica, una alternativa a modelos no lineales se obtiene con modelos lineales para cada tramo, modificando así las condiciones iniciales del esquema en diferencias finitas estocásticas que regula la generación del proceso a partir del punto de ruptura. EI procedimiento propuesto, que precisa dispaner de un cierto número de observaciones tras el momento de ruptura, permite obtener la evolución subyacente de una serie en el entorno del período temporal específico evitando los inconveníentes de los procedimientos anteriores. Con el objeto de desarrollar esta idea, el trabajo analiza la seríe de importaciones no energóticas.Publicad

Agronomic, economic and ecological aspects of the papaya (Carica papaya) production in Tabasco, Mexico

The cultivation of papaya is important in the tropic because it provides source of income to the farmer within a short time. Statistical data were obtained from farmers located in the Chontalpa, Rios and Centro-Sierra regions; the size of the survey was 67 farmers. The study shows the results of the farmers’ problem in a drastic reduction of their productivity because of the virosis and low prices in commercialization. The farmers were classified into three levels of technology, “low”, “middle” and “high”. The first one covers 88% of the farmers in seasonal conditions in contrast with the high technology that concentrates 4.5% in irrigation conditions. According to the technology used, the fertilizer shows more yields. Economically, the high technology had an internal tax return of 0.43 in comparison with the low technology of 0.25, which means that the investment is recovered with different yields. However, the use of high technology makes the system more competitive. Key words

A Highly Optimized Skeleton for Unbalanced and Deep Divide-And-Conquer Algorithms on Multi-Core Clusters

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG [Abstract] Efficiently implementing the divide-and-conquer pattern of parallelism in distributed memory systems is very relevant, given its ubiquity, and difficult, given its recursive nature and the need to exchange tasks and data among the processors. This task is noticeably further complicated in the presence of multi-core systems, where hybrid parallelism must be exploited to attain the best performance, and when unbalanced and deep workloads are considered, as additional measures must be taken to load balance and avoid deep recursion problems. In this manuscript a parallel skeleton that fulfills all these requirements while providing high levels of usability is presented. In fact, the evaluation shows that our proposal is on average 415.32% faster than MPI codes and 229.18% faster than MPI + OpenMP benchmarks, while offering an average improvement in the programmability metrics of 131.04% over MPI alternatives and 155.18% over MPI + OpenMP solutions.This research was supported by the Ministry of Science and Innovation of Spain (PID2019-104184RB-I00 and PID2019-104834GB-I00, AEI/FEDER/EU, 10.13039/501100011033) and the predoctoral Grant of Millán Álvarez Ref. BES-2017-081320), and by the Xunta de Galicia co-founded by the European Regional Development Fund (ERDF) under the Consolidation Programme of Competitive Reference Groups (ED431C 2018/19 and ED431C 2021/30). We acknowledge also the support from the Centro Singular de Investigación de Galicia “CITIC” and the Centro Singular de Investigación en Tecnoloxías Intelixentes “CiTIUS”, funded by Xunta de Galicia and the European Union (European Regional Development Fund- Galicia 2014-2020 Program), by Grants ED431G 2019/01 and ED431G 2019/04. We also acknowledge the Centro de Supercomputación de Galicia (CESGA). Open Access funding provided thanks to the CRUE-CSIC agreement with Springer NatureXunta de Galicia; ED431C 2018/19Xunta de Galicia; ED431C 2021/30Xunta de Galicia; ED431G 2019/01Xunta de Galicia; ED431G 2019/0

Luxación Posterior de Hombro

Se presentan cuatro casos de luxación posterior de hombro , de etiología trau - mática aguda . Se realiza una reseña de las características anatomopatológicas, del estudio clínico y radiográfico así como del tratamiento que fué conservador en todos los casos, utilizándose sólo en dos casos de reducción inestable fijación con agujas de Kirschner. La valoración de los resultados fué uniformemente buenaTh e author s repor t fou r case s o f posterio r shoulde r dislocatio n o f traumati c etiology , emphasizin g th e followin g aspects: Clinica l an d X-ra y traits, the - rapeuti c procedure s an d follow-u p results. Tw o case s wer e treate d withou t surger y a n d anothe r tw o stabilizatio n wit h Kirschne r wire s wa s used . En d results wer e uniformel y good

Luxación Acromioclavicular en los Niños

Se presentan cuatro pacientes con diagnóstico de pseudoluxación acromioclavicular tratados en nuestro Hospital. Se describen los tratamientos realizados y se discute la conveniencia de realizar tratamiento quirúrgico de los casos con mayor desplazamiento en pacientes menores de quince años a fin de evitar la aparición de una clavicula en "Y". Mantienen la misma indicación en pacientes de más edad en los que la anatomía patológica presenta similitud y en los que , aunque el periostio no tiene ya esa capacidad de neoformación, el proceder quirúrgico logra un buen a reducción estable.Th e author s presen t fou r case s o f patients wit h a diagnosis o f acro - mioclavicula r pseudodislocatio n treate d i n thei r hospital . The y describ e th e treatments carrie d ou t an d discuss th e suitabilit y o f surger y i n case s o f majo r displace - men t in patients younge r tha n 1 5 year s o f age , s o a s t o avoi d th e occurrenc e o f a "Y" clavicle . The y suppor t th e sam e suggestio n i n th e cas e o f olde r patients whe n the y sho w a simila r pathologica l anatom y an d surger y is expecte d t o achiev e a goo d an d stabl e reduction , althoug t thei r periostiu m keep s a neoformin g capabilit y an y more

Hemangioendotelioma de Humero

Se describe un caso de hemangioendotelioma grado I, que afectaba a la epífisis humeral superior en una paciente de cincuenta y siete años, presentándose clínicamente como una periartritis escapulo humeral. Se comenta el diagnóstico diferencial y el tratamiento que fué de resección local y sustitución del tercio superior del húmero por una prótesis isoelástica, más radioterapia complementaria. Después de ocho meses no hay evidencia de recidiva local o sistémica, ha desaparecido el dolor y la funcionalidad de la extremidad es aceptable. Se destaca la importancia del estudio anatomopatológico como guía casi única para el diagnóstico y la necesidad de realizar la gradación histológica de la malignidad como base para emitir un pronóstico e indicar la terapéutica, así como el rastreo del resto del esqueleto, tanto ante la lesión primaria como en las sucesivas revisiones.This is a report on a case of Hemangioendothelioma grade I located over the uppe r humeral epiphysis, in a woman aged 57, and mimicing scapulohume - ral periarthitis. The authors detail differential diagnosis and treatment consisting of partial ablation and us e a humeral isoelastic prosthesis as well as complementary radioterapy. After 8 months there is no evidence of local recidives or systemic, no pain, and the function of the limb is acceptable. They emphazise the importance of the pathologic as a true valid guidanc e concerning the diagnosis, and the necessity of a histologic typing to set both pronosti c and terapeutic planing. General skeletic X-Ray examination in the benning and also during the follow-up is also of paramount importance

Utilidad de la exploración física para el diagnóstico de neumonía infantil adquirida en la comunidad en un centro de atención primaria

ObjetivoDeterminar la utilidad diagnóstica de tres signos clínicos (fiebre, tos, estertores crepitantes) para el diagnóstico de neumonía en niños; evaluar la concordancia en la interpretación de la radiografía de tórax por dos radiólogosDiseñoEstudio de pruebas diagnósticasEmplazamientoAtención primariaMaterialTrescientas cincuenta historias clínicas de niños a los que se practicó una radiografía de tórax urgente para diagnosticar neumonía entre el 1 de enero de 1996 y el 30 de junio de 1999Mediciones principalesa) Prevalencia de neumonía en toda la muestra y en dos subgrupos de edad: igual o inferior a 5 años y superior a 5 años; b) cocientes de probabilidad positivo y negativo e intervalos de confianza del 95% (IC del 95%). Se consideró la radiografía de tórax como estándar de referencia, y c) concordancia interradiólogos-índice kappa (?)ResultadosLa prevalencia de neumonía en toda la muestra fue del 22,9% (IC del 95%, 18,5-27,3); en los niños de 5 años de edad o menores fue del 20,4% (IC del 95%, 15,6- 25,2), y en los mayores de 5 años, del 31,3% (IC del 95%, 21,1-41,4). Los signos estudiados sólo tuvieron alguna utilidad para confirmar el diagnóstico en mayores de 5 años: el cociente de probabilidad positivo fue de 3,52 (IC del 95%, 1,28-9,69) y los radiólogos coincidieron en el diagnóstico en el 93,1% de las radiografías de tórax (k=0,8; IC del 95%, 0,77-0,83)ConclusionesEn este estudio no se constató la presencia de un subconjunto de signos clínicos que aseguren de forma inequívoca el diagnóstico de neumonía en niñosObjectiveTo determine the diagnostic usefulness of three clinical signs (temperature, cough, crepitant stertor) for diagnosing pneumonia in children.To evaluate the agreement of two radiologists in evaluating thoracic x-rays (TXR)DesignStudy of diagnostic testsSettingPrimary careParticipants350 clinical histories of children who had an urgent TXR to diagnosis pneumonia between 1st January 1996 and 30th June 1999Main measurementsa) Prevalence of pneumonia in the entire sample and two age-based sub-groups: aged 5 years and under, and over 5; b) positive probability quotients (PQ+) and negative ones (PQ-) and 95% confidence intervals (95% CI). The TXR was seen as the reference standard, and c) kappa index (?) for inter-radiologist concordanceResultsPrevalence: the entire sample, 22.9% (95% CI, 18.5-27.3); children aged 5 or less, 20.4% (95% CI, 15.6-25.2); aged over 5, 31.3% (95% CI, 21.1-41.4). The signs studied were only of any use in confirming the diagnosis in children over 5: PQ+ was 3.52 (1.28-9.69). Radiologists coincided in their diagnosis in 93.1% of the TXR (k=0.8; 95% CI, 0.77-0.83)ConclusionsThis study did not prove that there was a sub-grouping of clinical signs which confirmed unmistakeably the diagnosis of pneumonia in childre

A novel approach to forecast urban surface-level ozone considering heterogeneous locations and limited information

Surface ozone (O3) is considered an hazard to human health, affecting vegetation crops and ecosystems. Accurate time and location O3 forecasting can help to protect citizens to unhealthy exposures when high levels are expected. Usually, forecasting models use numerous O3 precursors as predictors, limiting the reproducibility of these models to the availability of such information from data providers. This study introduces a 24 h-ahead hourly O3 concentrations forecasting methodology based on bagging and ensemble learning, using just two predictors with lagged O3 concentrations. This methodology was applied on ten-year time series (2006–2015) from three major urban areas of Andalusia (Spain). Its forecasting performance was contrasted with an algorithm especially designed to forecast time series exhibiting temporal patterns. The proposed methodology outperforms the contrast algorithm and yields comparable results to others existing in literature. Its use is encouraged due to its forecasting performance and wide applicability, but also as benchmark methodology

qq-Classical orthogonal polynomials: A general difference calculus approach

It is well known that the classical families of orthogonal polynomials are characterized as eigenfunctions of a second order linear differential/difference operator. In this paper we present a study of classical orthogonal polynomials in a more general context by using the differential (or difference) calculus and Operator Theory. In such a way we obtain a unified representation of them. Furthermore, some well known results related to the Rodrigues operator are deduced. A more general characterization Theorem that the one given in [1] and [2] for the q-polynomials of the q-Askey and Hahn Tableaux, respectively, is established. Finally, the families of Askey-Wilson polynomials, q-Racah polynomials, Al-Salam & Carlitz I and II, and q-Meixner are considered. [1] R. Alvarez-Nodarse. On characterization of classical polynomials. J. Comput. Appl. Math., 196:320{337, 2006. [2] M. Alfaro and R. Alvarez-Nodarse. A characterization of the classical orthogonal discrete and q-polynomials. J. Comput. Appl. Math., 2006. In press.Comment: 18 page