836 resultados para Teaching and learning of Natural Sciences in the early years


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The objective of this cross-sectional and quantitative study was to identify the prevalence and determinants of exclusive breastfeeding among infants less than six months of age in the city of Serrana, Sao Paulo, Brazil in 2009. A validated semi-structured questionnaire was administered to the guardians of the children less than six months of age who attended the second phase of a Brazilian vaccination campaign against polio. Univariate and multivariate analysis presented in odds ratios and confidence intervals was accomplished. Of the total of 275 infant participants, only 29.8% were exclusively breastfed. Univariate analysis revealed that mothers who work outside the home without maternity leave, mothers who did not work outside the home, adolescent mothers, and the use of pacifiers have a greater chance of interrupting exclusive breastfeeding. In the multivariate analysis, mothers who work outside the home without maternity leave are three times more likely to wean their children early. Results provide suggestions for the redirection and planning of interventions targeting breastfeeding.

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Mischocyttarus cassununga, a primitively eusocial Brazilian wasp, commonly found in urban environments, is an interesting model for studies on the evolution of social behaviour in hymenopteran insects. In this study, we constructed a microsatellite-enriched genomic library and presented primers for 18 microsatellite loci. For the analysis, 20 unrelated females were screened and all loci obtained were polymorphic. PCR amplification revealed from 3 (Mcas5b) to 17 (Mcas53b) alleles per locus (). We detected the levels of observed (H (o)) and expected (H (e)) heterozygosities ranging from 0.150 to 0.950 and 0.261 to 0.920, respectively. The polymorphic information content ranged from 0.238 to 0.915, averaging 0.680. All loci were in Hardy-Weinberg equilibrium and linkage disequilibrium was not detected after sequential Bonferroni correction (P > 0.05). These molecular markers will allow further studies on sociogenetic structure, extensive population genetic analysis and diversity of M. cassununga and other Mischocyttarini species.

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Background: Given the established fact that obesity interferes with male reproductive functions, the present study aimed to evaluate sperm production in the testis and storage in the epididymis in a glutamate-induced model of obesity. Methods: Male rats were treated neonatally with monosodium glutamate (MSG) at doses of 4 mg/kg subcutaneously, or with saline solution (control group), on postnatal days 2, 4, 6, 8 and 10. On day 120, obesity was confirmed by the Lee index in all MSG-treated rats. After this, all animals from the two experimental groups were anesthetized and killed to evaluate body and reproductive organ weights, sperm parameters, plasma hormone levels (FSH, LH and testosterone), testicular and epididymal histo-morphometry and histopathology. Results: Significant reductions in absolute and relative weights of testis, epididymis, prostate and seminal vesicle were noted in MSG-treated animals. In these same animals plasma testosterone and follicle-stimulating hormone (FSH) concentrations were decreased, as well as sperm counts in the testis and epididymis and seminiferous epithelium height and tubular diameter. The sperm transit time was accelerated in obese rats. However, the number of Sertoli cells per seminiferous tubule and stereological findings on the epididymis were not markedly changed by obesity. Conclusions: Neonatal MSG-administered model of obesity lowers sperm production and leads to a reduction in sperm storage in the epididymis of adult male rats. The acceleration of sperm transit time can have implications for the sperm quality of these rats.

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This work aimed to evaluate the incidence and severity of scab in prune trees under different fungicide management, with two time patterns of application; one at the early fruit formation, up to pit hardening, and another starting after pit hardening, and compare the number of fungicide application reductions with the management adopted by the producer Four experiments, with different treatments, were carried out during the 2004-2005 and 2005-2006 seasons (two experiments,) and that of 2008-2009, using the Harry Pickstone and Reubennel cultivars. The most efficient control of the disease was achieved with the combination of metiram, piraclostrobina e ditianona fungicides from late bloom to pit hardening. Efficient scab control in prune was dependent on the combination of the fungicides used and the application timing. Reduced fungicide management is possible, while spraying initiated after pit hardening was not efficient for scab control.

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Programa de doctorado en Oceanografía

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The Ecosystem Approach to Fisheries represents the most recent research line in the international context, showing interest both towards the whole community and toward the identification and protection of all the “critical habitats” in which marine resources complete their life cycles. Using data coming from trawl surveys performed in the Northern and Central Adriatic from 1996 to 2010, this study provides the first attempt to appraise the status of the whole demersal community. It took into account not only fishery target species but also by-catch and discharge species by the use of a suite of biological indicators both at population and multi-specific level, allowing to have a global picture of the status of the demersal system. This study underlined the decline of extremely important species for the Adriatic fishery in recent years; adverse impact on catches is expected for these species in the coming years, since also minimum values of recruits recently were recorded. Both the excessive exploitation and environmental factors affected availability of resources. Moreover both distribution and nursery areas of the most important resources were pinpointed by means of geostatistical methods. The geospatial analysis also confirmed the presence of relevant recruitment areas in the North and Central Adriatic for several commercial species, as reported in the literature. The morphological and oceanographic features, the relevant rivers inflow together with the mosaic pattern of biocenoses with different food availability affected the location of the observed relevant nursery areas.

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Il vento di barriera (VB) è un fenomeno meteorologico a mesoscala che interessa il flusso nei bassi strati atmosferici ed è dovuto all'interazione con l'orografia. Se il numero di Froude upstream è sufficientemente piccolo si genera una deviazione orizzontale del flusso incidente. Si può raggiungere uno stato quasi-stazionario, nel quale un intenso vento soffia parallelo all'orografia nei bassi strati. Nel presente lavoro si è innanzitutto sviluppata una climatologia degli eventi di VB nella regione italiana su un periodo biennale. Gli eventi sono stati classificati per la velocità del flusso incidente e la velocità e direzione del VB a 950 hPa, e per il numero di Froude upstream. Si è poi studiata la distribuzione degli eventi rispetto al numero di Froude. La climatologia è risultata in buon accordo con la teoria idealizzata dei flussi sopra l'orografia. Tre casi di studio sono stati successivamente simulati utilizzando i modelli BOLAM e MOLOCH dell'istituto CNR-ISAC di Bologna. Per ciascun evento sono stati calcolati il numero di Froude upstream e i parametri principali, quali velocità, estensione, temperatura ecc. Per uno dei casi, riguardante le Alpi orientali, le simulazioni sono state confrontate con dati osservati di vento, pressione, temperatura e precipitazione. Sono poi stati condotti dei sensitivity tests con orografia diminuita su ognuno degli eventi. È stata così verificata l'importanza dell'effetto orografico e l'intensità del fenomeno del VB è stata associata al numero di Froude. Un indice, denominato Barrier Wind Index (BWI) è stato ideato a tale scopo. Le simulazioni hanno mostrato un buon accordo con la teoria, indicandone i limiti di applicabilità all'atmosfera reale. In particolare, il Barrier Wind Index tende ad aumentare linearmente al diminuire del numero di Froude. Le simulazioni hanno evidenziato l'elevata influenza del VB sulla circolazione atmosferica a mesoscala, sulla distribuzione e intensità della precipitazione e sull'avvezione di temperatura e umidità.

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The advent of highly active antiretroviral therapy (HAART) in 1996 led to a decrease in the incidence of Kaposi's sarcoma (KS) and non-Hodgkin's lymphoma (NHL), but not of other cancers, among people with HIV or AIDS (PWHA). It also led to marked increases in their life expectancy.

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Metabolic and endocrine adaptations to support milk production during the transition period vary between individual cows. This variation between cows to adapt to lactation may have a genetic basis. The present field study was carried out to determine hepatic adaptations occurring from late pregnancy through early lactation by measuring mRNA abundance of candidate genes in dairy cows on-farm. Additionally, the objective was to observe the diversity in inter-individual variation for the candidate genes that may give indications where individual adaptations at a molecular level can be found. This study was carried out on-farm including 232 dairy cows (parity >3) from 64 farms in Switzerland. Blood and liver samples were collected on d 20+/-7 before parturition, on d 24+/-2, and on d 89+/-4 after parturition. Blood plasma was assayed for concentrations of glucose, nonesterified fatty acids, beta-hydroxybutyrate, cholesterol, triglycerides, urea, albumin, protein, insulin, insulin-like growth factor-1, leptin, 3,5,3'-triiodothyronine, and thyroxine. Liver samples were obtained at the same time points and were measured for mRNA abundance of 26 candidate genes encoding enzymes and nuclear receptors involved in gluconeogenesis, fatty acid beta-oxidation, fatty acid and triglyceride synthesis, ketogenesis, citric acid cycle, cholesterol synthesis, and the urea cycle. The cows in the present study experienced a marked metabolic load in early lactation, as presented by changes in plasma metabolites and hormones, and responded accordingly with upregulation and downregulation of almost all candidate genes involved in metabolic processes in the liver. The observed inter-individual variation for the candidate genes, which was highest for acetyl-CoA-carboxylase and glycerol-3-phosphate dehydrogenase 2, should be further investigated to unravel the regulation at molecular level for optimal adaptive performance in dairy cows.