A Review on Fractional Differential Equations and a Numerical Method to Solve Some Boundary Value Problems

Fractional differential equations can describe the dynamics of several complex and nonlocal systems with memory. They arise in many scientific and engineering areas such as physics, chemistry, biology, biophysics, economics, control theory, signal and image processing, etc. Particularly, nonlinear systems describing different phenomena can be modeled with fractional derivatives. Chaotic behavior has also been reported in some fractional models. There exist theoretical results related to existence and uniqueness of solutions to initial and boundary value problems with fractional differential equations; for the nonlinear case, there are still few of them. In this work we will present a summary of the different definitions of fractional derivatives and show models where they appear, including simple nonlinear systems with chaos. Existing results on the solvability of classical fractional differential equations and numerical approaches are summarized. Finally, we propose a numerical scheme to approximate the solution to linear fractional initial value problems and boundary value problems

La nueva derivada de Caputo: Cálculo aproximado de primitivas utilizando una familia de wavelets de banda limitada

La nueva derivada de Caputo está definida mediante un operador integral con núcleo regular,(M. Caputo and M. Fabrizio, Nat Sc Pub Cor, Prog in Frac Diff and App, (1): 73-85, (2015)). En este trabajo, continuación de (M. Troparevsky et. al., Asoc Arg Mec Comp, 3383-3394, (2016)), resolvemos aproximadamente el problema inverso que consiste en el cálculo de una función de la cual se conoce esta nueva derivada fraccionaria. Para calcular aproximadamente una primitiva elegimos una familia de wavelets de banda limitada de propiedades especiales asociadas a un análisis de multirresolución. Descomponemos y proyectamos el dato y mediante un esquema tipo Galerkin calculamos los coeficientes de la incógnita en dicha base. El esquema de aproximación resulta simple y eficiente gracias a la regularidad del operador y a las propiedades de la familia de wavelets elegida.Publicado en: Mecánica Computacional vol. XXXV no.44Facultad de Ingenierí

IRAKA: The first Colombian soil information system with digital soil mapping products

Los avances en ciencia y tecnología combinados con la necesidad de manejar y administrar los recursos naturales han resultó en un aumento gradual en la disponibilidad de datos del suelo. Esto ha permitido caracterizar, describir o proponer proyectos para abordar cuestiones como la degradación del suelo, la productividad agrícola, las amenazas y los servicios de los ecosistemas. A pesar de la disponibilidad de datos del suelo, los usuarios buscan cada vez más información adicional, oportuna y confiable. para dar respuesta a situaciones actuales y futuras, como la seguridad alimentaria y el cambio climático. IRAKA es un suelo sistema de información para el altiplano cundiboyacense colombiano y el primero en brindar información adicional de fuentes oficiales disponibles. Tiene un diseño modular basado en la organización de una base de datos de suelos cuya estructura incorporó 299 perfiles, 1432 muestras y 55 propiedades y la integración, armonización, y estandarización de 8 estudios de suelos realizados en la zona. La información estructurada permitió modelar y validando las propiedades físicas y químicas a través del mapeo digital del suelo y comparando diferentes máquinas técnicas de aprendizaje, incluyendo bosque aleatorio, guardabosques, máquina de vectores de apoyo y modelos de conjunto de estos Técnicas Las interpolaciones de 11 propiedades cuantitativas y 1 propiedad cualitativa resultaron en aceptables coeficientes de bondad de ajuste debido a diferentes factores: variabilidad de la propiedad, representatividad, distribución en el área de estudio y descripción de la propiedad basada en covariables ambientales. Toda la información generada ha sido disponible para un uso generalizado en diferentes servicios web geográficos. Así, IRAKA contribuye a la gestión de la información y el conocimiento a través de técnicas y herramientas que permiten a los usuarios visualizar nuevos información, utilizar la información y llamar la atención sobre nuevos estudios y mejorar las bases de datos en las que la confianza el nivel es insuficiente y no permite la toma de decisiones

AVALIAÇÃO ELETROCARDIOGRÁFICA EM ANTAS (Tapirus terrestris)

O objetivo desse trabalho foi estabelecer parâmetros eletrocardiográficos para a anta (T. terrestris), servindo como referência normal para a espécie. Foram utilizados machos adultos de anta brasileira (n=11), com peso entre 160 a 220 kg e idade entre 3 a 28 anos. Os animais estavam alojados em cativeiro na Itaipu Binacional (Brasil e Paraguai). Os resultados estão expressos na forma de média ± desvio padrão. Os parâmetros obtidos em DII (derivação II) foram a frequência cardíaca (FC) = 63 ± 22 bpm, ritmo cardíaco (sinusal), eixo elétrico médio (EEM) = 70,00º ± 81,22º; duração de P = 0,05 ± 0,02 s; amplitude de P = 0,16 ± 0,07mV, duração de QRS = 0,08 ± 0,02 s; amplitude de R = 0,74 ± 0,41 mV; duração do intervalo PR = 0,19 ± 0,06 s e duração de QT = 0,40 ± 0,14 s. Na observação de dados publicados em evento cientifico, com exceção da amplitude de P (2,3 vezes maior no presente estudo), todas as outras variáveis estão próximas para a mesma espécie. Verificou-se que a FC das antas sob efeito dos anestésicos utilizados (cetamina 10%; detomidina 1%; butorfanol 1%; com adição de atropina na presença de secreção respiratória abundante) é 1,5 vezes maior que a FC média de equinos adultos não anestesiados em repouso. No intervalo PR, duração de P e amplitude de R observou-se que equinos têm valores duas a quatro vezes maiores que os das antas. A duração de QRS em antas chega a pouco menos que duas vezes menor, quando comparada com a de equinos. A FC maior pode estar relacionada a um provável maior metabolismo das antas, considerando que são animais com menor massa corporal do que os equinos. O menor intervalo PR das antas também pode ser atribuído a este fato. A menor duração de P e de QRS e da amplitude de R pode estar relacionada com o menor tamanho do coração das antas

Differences among Sociodemographic Variables, Physical Fitness Levels, and Body Composition with Adherence to Regular Physical Activity in Older Adults from the EXERNET Multicenter Study

[EN] The aim of this study was to explore the differences among between adherence to physical activity (PA) and sociodemographic variables, body composition, and physical fitness levels in older adults (>65 years). A number of 2712 participants (2086 female; 76.92%) ranging from 65 to 92 years, participated in the study. Stages of change (SoC) for PA from the transtheoretical model of change (TTM), together with different sociodemographic variables, physical fitness tests (Senior Fitness Test), and waist and hip circumferences were evaluated. Significant differences were found in age, gender, educational level, current income, physical fitness test, and body composition (all of them, p < 0.05), according to the different SoC. Greater adherence to PA practice (action and maintenance stages) was related to better academic level, higher economic income, the male gender, better results in the physical fitness test, and healthier anthropometrics perimeters. Future research is needed to identify the relationship between these variables longitudinally.SIMinisterio de Ciencia, Innovación y Universidades, Gobierno de Españ

Exposição a pesticidas e genótipo heterozigoto de GSTP1-Alw26I associam-se à doença de Parkinson

Objective This study aimed to analyze the frequency of GSTP1-Alw26I polymorphism and to estimate its association with toxic substances in Parkinson's disease (PD). Methods A study group with 154 patients - subdivided into familial and sporadic PD groups - and 158 elderly individuals without the disease (control group) were evaluated. GSTP1-Alw26I polymorphism was analyzed by polymerase chain reaction/restriction fragment length polymorphism (PCR-RFLP). Results Patients were significantly more exposed to pesticides compared with the control group (p=0.0004), and the heterozygote genotype associated to exposure to pesticides also prevailed in patients (p=0.0001). Wild homozygote genotype was related to tobacco use (p=0.043) and alcoholism (p=0.033) in familial PD patients. Conclusion Exposure to pesticides is associated to PD, whose effect can be enhanced when combined with the heterozygote genotype of GSTP1-Alw26I. Also, large genetic and environmental studies considering tobacco use, alcoholism, GSTP1 and PD are necessary to confirm our findings.Objetivo Analisar a frequência do polimorfismo GSTP1-Alw26I, assim como estimar sua associação com substâncias tóxicas na doença de Parkinson (DP). Métodos A casuística avaliada foi composta por um grupo de estudo, com 154 pacientes, subdivididos em DP familial e esporádica, e outro com 158 idosos sem a doença (grupo controle). O polimorfismo GSTP1-Alw26I foi analisado por reação em cadeia da polimerase/polimorfismo de comprimento do fragmento de restrição (PCR/RFLP). Resultados Os pacientes foram significativamente mais expostos a pesticidas, comparados com o grupo controle (p=0,0004), e o genótipo heterozigoto associado a exposição a pesticidas também prevaleceu nos pacientes (p=0,0001). O genótipo homozigoto selvagem apresentou relação com tabagismo (p=0,043) e etilismo (p=0,033) em pacientes com DP familial. Desse modo, a exposição a pesticidas está associada à DP, cujo efeito pode ser potencializado quando combinado ao genótipo heterozigoto de GSTP1-Alw26I. Estudos genético-ambientais envolvendo tabagismo, etilismo, GSTP1 e DP devem ser realizados em casuísticas numerosas, confirmando essa associação.Sao Jose do Rio Preto Medical School Department of NeuroscienceFAMERPFederal University of São PauloHospital de BaseUNIFESPSciEL

Wild dogs at stake: deforestation threatens the only Amazon endemic canid, the short-eared dog (Atelocynus microtis)

The persistent high deforestation rate and fragmentation of the Amazon forests are the main threats to their biodiversity. To anticipate and mitigate these threats, it is important to understand and predict how species respond to the rapidly changing landscape. The short-eared dog Atelocynus microtis is the only Amazon-endemic canid and one of the most understudied wild dogs worldwide. We investigated short-eared dog habitat associations on two spatial scales. First, we used the largest record database ever compiled for short-eared dogs in combination with species distribution models to map species habitat suitability, estimate its distribution range and predict shifts in species distribution in response to predicted deforestation across the entire Amazon (regional scale). Second, we used systematic camera trap surveys and occupancy models to investigate how forest cover and forest fragmentation affect the space use of this species in the Southern Brazilian Amazon (local scale). Species distribution models suggested that the short-eared dog potentially occurs over an extensive and continuous area, through most of the Amazon region south of the Amazon River. However, approximately 30% of the short-eared dog's current distribution is expected to be lost or suffer sharp declines in habitat suitability by 2027 (within three generations) due to forest loss. This proportion might reach 40% of the species distribution in unprotected areas and exceed 60% in some interfluves (i.e. portions of land separated by large rivers) of the Amazon basin. Our local-scale analysis indicated that the presence of forest positively affected short-eared dog space use, while the density of forest edges had a negative effect. Beyond shedding light on the ecology of the short-eared dog and refining its distribution range, our results stress that forest loss poses a serious threat to the conservation of the species in a short time frame. Hence, we propose a re-assessment of the short-eared dog's current IUCN Red List status (Near Threatened) based on findings presented here. Our study exemplifies how data can be integrated across sources and modelling procedures to improve our knowledge of relatively understudied species

Independent and joined association between socioeconomic indicators and pediatric obesity in Spain: the PASOS study

Childhood obesity is a public health problem worldwide. An important determinant of child and adolescent obesity is socioeconomic status (SES). However, the magnitude of the impact of different SES indicators on pediatric obesity on the Spanish population scale is unclear. The aim of this study was to assess the association between three SES indicators and obesity in a nationwide, representative sample of Spanish children and adolescents. A total of 2791 boys and girls aged 8 to 16 years old were included. Their weight, height, and waist circumference were measured. SES was assessed using two parent/legal guardian self-reported indicators (educational level -University/non-University- and labor market status -Employed/Unemployed-). As a third SES indicator, the annual mean income per person was obtained from the census section where the participating schools were located (≥12.731€/<12.731€). The prevalence of obesity, severe obesity, and abdominal obesity was 11.5%, 1.4%, and 22.3%, respectively. Logistic regression models showed an inverse association of both education and labor market status with obesity, severe obesity, and abdominal obesity (all p < 0.001). Income was also inversely associated with obesity (p < 0.01) and abdominal obesity (p < 0.001). Finally, the highest composite SES category (University/Employed/≥12.731€ n = 517) showed a robust and inverse association with obesity (OR = 0.28; 95% CI: 0.16–0.48), severe obesity (OR = 0.20; 95% CI: 0.05–0.81), and abdominal obesity (OR = 0.36; 95% CI: 0.23–0.54) in comparison with the lowest composite SES category (Less than University/Unemployed/<12.731€; n = 164). No significant interaction between composite SES categories and age and gender was found. SES is strongly associated with pediatric obesity in Spain.The PASOS study was funded by Fundación PROBITAS (2019) and the Gasol Foundation (2019-2020). Additional funds were received from the Barça Foundation (2019-2020), Banco Santander (2019), IFA (2019-2020), Vienna (2019), and the Fundación Deporte Joven (2019) (no references are applicable). J.A.T., M.G.-G. and C.B. are funding by Instituto de Salud Carlos III through the CIBEROBN CB12/03/30038, which are co-funded by the European Regional Development Fund