2,745 research outputs found
Controle de vira-cabeça do tomateiro pela destruição do vector
Uma serie de três ensaios com nove inseticidas diferentes foi realizada para estudar seus efeitos sobre o controle do tripes vector de vira-cabeca. Granutox-S, aplicado no solo, Folidol 60 (0,25%) e Dieldrex 20 (2,0%), em pulverizações foliares, apresentaram os melhores resultados; Metasystox (i) (0,4%) e Phosdrin C. E. 2 (1,0%), em pulverizações, também foram bastante promissores para o controle da moléstia. À redução na porcentagem de infecção com a moléstia nos melhores tratamentos não correspondeu grande aumento de produção, em comparação com a testemunha . Isto foi atribuÃdo, em parte, ao efeito fitotóxico de alguns inseticidas, uma vez que foram aplicados em concentrações bem mais elevadas do que as recomendadas pelos fabricantes
Effects of different exercise frequencies on body composition and physical fitness in overweight and obese young school-aged children
Introduction: Obesity is considered to be one of the epidemics of the 21st century and the perspective is to increase in children and adolescents¹. Furthermore, physical activity supplies health benefits by increasing
children’s aerobic fitness, bone mass and high-density lipoprotein (HDL) cholesterol, and by helping to reduce
chronic diseases like obesity and hypertension. Public health physical activity guidelines address the exercise
needs of children and adolescents². However, there are few published studies that demonstrate what are
the most effective exercise frequencies to obtain better results in body composition and physical fitness.
The purpose of this study was to evaluate short-term effects of multicomponent exercise training with
different exercise frequencies on body composition (BC) and physical fitness (PF) in overweight and obese
young school-aged children
Ward identities for the Anderson impurity model: derivation via functional methods and the exact renormalization group
Using functional methods and the exact renormalization group we derive Ward
identities for the Anderson impurity model. In particular, we present a
non-perturbative proof of the Yamada-Yosida identities relating certain
coefficients in the low-energy expansion of the self-energy to thermodynamic
particle number and spin susceptibilities of the impurity. Our proof underlines
the relation of the Yamada-Yosida identities to the U(1) x U(1) symmetry
associated with particle number and spin conservation in a magnetic field.Comment: 8 pages, corrected statements about infintite flatband limi
In situ study of the endotaxial growth of hexagonal CoSi2 nanoplatelets in Si(001)
This investigation aims at studying-by in situ grazing-incidence small-angle x-ray scattering-the process of growth of hexagonal CoSi2 nanoplatelets endotaxially buried in a Si(001) wafer. The early formation of spherical Co nanoparticles with bimodal size distribution in the deposited silica thin film during a pretreatment at 500 °C and their subsequent growth at 700 °C were also characterized. Isothermal annealing at 700 °C promotes a drastic reduction in the number of the smallest Co nanoparticles and a continuous decrease in their volume fraction in the silica thin film. At the same time, Co atoms diffuse across the SiO2/Si(001) interface into the silicon wafer, react with Si, and build up thin hexagonal CoSi2 nanoplatelets, all of them with their main surfaces parallel to Si{111} crystallographic planes. The observed progressive growths in thickness and lateral size of the hexagonal CoSi2 nanoplatelets occur at the expense of the dissolution of the small Co nanoparticles that are formed during the pretreatment at 500 °C and become unstable at the annealing temperature (700 °C). The kinetics of growth of the volume fraction of hexagonal platelets is well described by the classical Avrami equation.Fil: Costa, Daniel Da Silva. Universidade Federal do Paraná; BrasilFil: Huck Iriart, Cristián. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - La Plata. Instituto de Investigaciones FisicoquÃmicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones FisicoquÃmicas Teóricas y Aplicadas; ArgentinaFil: Kellermann, Guinther. Universidade Federal do Paraná; BrasilFil: Giovanetti, Lisandro Jose. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - La Plata. Instituto de Investigaciones FisicoquÃmicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones FisicoquÃmicas Teóricas y Aplicadas; ArgentinaFil: Craievich, Aldo F.. Universidade de Sao Paulo; BrasilFil: Requejo, Felix Gregorio. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - La Plata. Instituto de Investigaciones FisicoquÃmicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones FisicoquÃmicas Teóricas y Aplicadas; Argentin
Interactional response during infants’ aquatic sessions
The aim of study was to assess infants’ behaviour during routine
swimming sessions using a naturalistic observation method.
The study sample included 14 infants (13.7 ± 7.5 months old)
with previous aquatic experience. The frequency of occurrences
per unit of time (session) in the different dimensions –
infant’s motor behaviour and social-affective interaction – was
registered over the course of two sessions by two independent
experts. The behaviours most frequently observed were accompanied
displacement (61.1 %) and interaction with others
(41.6 %). Submersions or jumps represented only 8.4 % of the
session. Implementing a child-centred methodology leads to
positive behaviours during this type of sessions, contributing
to the child’s healthy development.info:eu-repo/semantics/publishedVersio
Critical velocity in swimming: a literature review
De entre as técnicas não invasivas de determinação do limiar anaeróbio, o método da determinação da velocidade crÃtica tem merecido grande atenção, nomeadamente no âmbito da avaliação e controlo do treino em natação. Neste sentido, o objetivo do presente artigo foi efetuar uma revisão da literatura do tipo qualitativa acerca do significado do parâmetro velocidade crÃtica e sua aplicação à natação. Foram abordadas questões relativas à origem e definição do conceito de velocidade crÃtica, à s metodologias de determinação mais comuns, bem como uma breve referência ao conceito de velocidade crÃtica anaeróbia. A velocidade crÃtica é sugerida como um parâmetro não invasivo de avaliação do desempenho aeróbio e de predição do limiar anaeróbio de nadadores, independentemente do nÃvel desportivo. As principais vantagens deste indicador resultam da facilidade de aplicação e análise num elevado número de nadadores, sem a necessidade da utilização de equipamentos dispendiosos ou de recolha de sangue. Aponta-se como uma ferramenta útil no mecanismo de prescrição e controlo de cargas de treino por meio de resultados em condições experimentais ou recorrendo a tempos obtidos durante as competições. A descriminação dos valores de velocidade crÃtica entre nadadores com diferentes perfis metabólicos (velocistas versus fundistas) e ainda a sua aplicabilidade em regime anaeróbio são aspetos que ainda carecem de um maior entendimento
The Effects of Concurrent Resistance and Endurance Training Follow a Specific Detraining Cycle in Young School Girls
The purpose of this study was to compare the effects of an 8-week training period of strength training alone (GR), or combined strength and endurance training (GCOM), followed by 12-weeks of de-training (DT) on body composition, power strength and VO2max adaptations in a schooled group of adolescent girls. Sixty-seven healthy girls recruited from a Portuguese public high school (age: 13.5+1.03 years, from 7(th) and 9th grade) were divided into three experimental groups to train twice a week for 8 wks: GR (n=21), GCOM (n=25) and a control group (GC: n=21; no training program). Anthropometric parameters variables as well as performance variables (strength and aerobic fitness) were assessed. No significant training-induced differences were observed in 1kg and 3kg medicine ball throw gains (2.7 to 10.8%) between GR and GCOM groups, whereas no significant changes were observed after a DT period in any of the experimental groups. Significant training-induced gains in CMVJ (8 to 12%) and CMSLJ (0.8 to 5.4%) were observed in the experimental groups. Time of 20m significantly decreased (GR: -11.5% and GCOM: -10%) after both treatment periods, whereas only the GR group kept the running speed after a DT period of 12 weeks. After training VO2max increased only slightly for GCOM (4.0%). No significant changes were observed after the DT period in all groups, except to GCOM in CMVJ and CMSLJ. Performing simultaneous strength and endurance training in the same workout does not appear to negatively influence power strength and aerobic fitness development in adolescent girls. Indeed, concurrent strength and endurance training seems to be an effective, well-rounded exercise program that can be prescribed as a means to improve initial or general strength in healthy school girls. De-training period was not sufficient to reduce the overall training effects.info:eu-repo/semantics/publishedVersio
Relationships Between Vertical Jump Strength Metrics and 5 Meters Sprint Time
The aim of this study was to examine the relationship between short sprint time (5 m) and strength metrics of the countermovement jump (CMJ) using a linear transducer in a group of trained athletes. Twenty-five male, trained subjects volunteered to participate in the study. Each volunteer performed 3 maximal CMJ trials on a Smith machine. Peak instantaneous power was calculated by the product of velocity taken with the linear transducer. For sprint testing, each subject performed three maximum 5 m sprints. Only the best attempt was considered in both tests. Pearson product-moment correlation coefficients between 5 m sprint performance and strength metrics of the CMJ were generally positive and of clear moderate to strong magnitude (r = -0.664 to -0.801). More noticeable was the significant predictive value of bar displacement time (r= ∼0.70) to sprint performance. Nevertheless, a non-significant predictive value of peak bar velocity and rate of force development measurements was found. These results underline the important relationship between 5 m sprint and maximal lower body strength, as assessed by the force, power and bar velocity displacement. It is suggested that sprinting time performance would benefit from training regimens aimed to improve these performance qualities.info:eu-repo/semantics/publishedVersio
Influence of sociological aspects on the level of physical activity in physical education students
Adopting and maintaining an active lifestyle for adolescent students, seems to be impaired and influenced by several factors, among them stand out environmental, psychological and social factors. Thus, the general objectives of this study were submitted to study and understand the extent to which these environmental, social and personal factors help and influence the level of physical activity (PA) by the adolescents in school age. More specifically, we will study: (1) the possible association between level of physical activity, age and gender; (2) consider and determine whether there is an association between socioeconomic variables and physical activity level of the population sample; (3) assess on the possible association between environmental variables and perceived physical activity of the adolescents. The sample consisted of 286 high school students, male gender (n = 125) and female (n = 161) aged between 15 and 18 years of age. As an instrument of study, a questionnaire was used. The main results of this study demonstrate a possible relationship between gender and level of PA, while boys tend to be more active than girls and also an association between socioeconomic variables and level of physical activity
DNA demethylation caused By 5-Aza-2'-Deoxycytidine induces mitotic alterations and aneuploidy
Aneuploidy, the unbalanced number of chromosomes in a cell, is considered a prevalent form of genetic instability and is largely acknowledged as a condition implicated in tumorigenesis. Epigenetic alterations like DNA hypomethylation have been correlated with cancer initiation/progression. Furthermore, a growing body of evidence suggests the involvement of epigenome-wide disruption as a cause of global DNA hypomethylation in aneuploidy generation. Here, we report that the DNA hypomethylating drug 5-aza-2'-deoxycytidine (DAC), affects the correct ploidy of nearly diploid HCT-116 human cells by altering the methylation pattern of the chromosomes. Specifically, we show that a DACinduced reduction of 5-Methyl Cytosine at the pericentromeric region of chromosomes correlates with aneuploidy and mitotic defects. Our results suggest that DNA hypomethylation leads to aneuploidy by altering the DNA methylation landscape at the centromere that is necessary to ensure proper chromosomes segregation by recruiting the proteins necessary to build up a functional kinetochore
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