ABSTRACT Population dynamics of aphids have been studied in sole and intercropping systems. These studies have required the use of more precise analytical tools in order to better understand patterns in quantitative data. Mathematical models are among the most important tools to explain the dynamics of insect populations. This study investigated the population dynamics of aphids Aphis gossypii and Aphis craccivora over time, using mathematical models composed of a set of differential equations as a helpful analytical tool to understand the population dynamics of aphids in arrangements of cotton and cowpea. The treatments were sole cotton, sole cowpea, and three arrangements of cotton intercropped with cowpea (t1, t2 and t3). The plants were infested with two aphid species and were evaluated at 7, 14, 28, 35, 42, and 49 days after the infestations. Mathematical models were used to fit the population dynamics of two aphid species. There were good fits for aphid dynamics by mathematical model over time. The highest population peak of both species A. gossypii and A. craccivora was found in the sole crops, and the lowest population peak was found in crop system t2. These results are important for integrated management programs of aphids in cotton and cowpea.

ABSTRACT The intercropping is an important cultural practice commonly used in pest management. It is based on the principle that increased plant diversity in the agro-ecosystem can lead to reductions of pest populations in the crop. The current study aimed to assess the impact the colored fiber cotton-cowpea intercropped systems on Aphis gossypii and Aphis craccivora and on their predator Cycloneda sanguinea and the losses and the dispersion behavior of these aphids and their predator in these cropping systems. The experiment had a randomized block experimental design with two bioassays and four treatments. The number of apterous and alate aphids (A. gossypii) per cotton plant was 1.46 and 1.73 or 1.97 and 2.19 times highest in the solid cotton system than that found in the cotton-cowpea intercropped systems (S1) and (S2), respectively. On the other hand, the cotton-cowpea intercropped systems (S1 and S2) reduced, respectively, in 43% and 31% the number of apterousA. gossypiiper cotton plant compared to the control. Implementing cotton-cowpea intercropped system in the S1 scheme reduced A. gossypii infestation, favored the multiplication of C. sanguinea, and allowed obtaining heavier open bolls.

RESUMO Leucose Enzoótica dos Bovinos (LEB) é uma retrovirose cosmopolita, que se alastra progressivamente pelos rebanhos determinando grandes prejuízos à bovinocultura brasileira. O objetivo deste estudo foi determinar a soroprevalência da LEB e investigar os fatores de risco associados à soropositividade dos rebanhos leiteiros criados na região Norte do Estado do Tocantins. Para isso, 881 amostras séricas, colhidas de 38 rebanhos leiteiros de 15 municípios do norte do Estado do Tocantins, foram examinadas pelo teste da Imunodifusão Radial Dupla de Ouchterlony em gel de Agar (IDGA-LEB) para detecção de anticorpos específicos anti-VLB. O teste de IDGA-LEB identificou uma prevalência de 37% (326/881), com intervalo de confiança entre 32,8% a 41,2%. Entre os fatores de risco analisados, o tipo de ordenha praticado nas propriedades manteve associação significante (p < 0,05) com a prevalência da LEB. A soropositividade observada na ampla maioria dos rebanhos examinados (94,7% 36/38), evidenciando o alastramento expressivo da LEB, sugere a conexão de sua gênese com a expansão da bovinocultura leiteira no Norte do Estado do Tocantins.

ABSTRACT Enzootic bovine leukosis (EBL) is a cosmopolitan retrovirosis that progressively spreads in herds causing great damage to Brazilian livestock. The aim of this study was to determine the seroprevalence of EBL and to research risk factors associated to the positive serology. For this purpose, 881 serum samples, collected from 38 dairy herds raised in northern Tocantins State, were examined by the agargel immunodiffusion test (AGID-EBL) for detection of specific anti-BLV antibodies. The AGIDEBL test showed a prevalence of 37% (326/881), with confidence interval from 32.8% to 41.2%. Among the analyzed risk factors, the milking system used on the properties presented significant correlation (p < 0.05) with the prevalence of EBL. The seropositivity observed in the greater part of the examined herds, exhibiting the expressive spreading of the BEL, suggests a connection between the number of seropositive animals and the spread of the dairy livestock in northern Tocantins State, Brazil.

Osteoporosis is a multifactorial disease with great impact on morbidity and mortality mainly in postmenopausal women. Although it is recognized that factors related to life-style and habits may influence bone mass formation leading to greater or lower bone mass, more than 85% of the variation in bone mineral density (BMD) is genetically determined. The collagen type I alpha 1 (COLIA1) gene is a possible risk factor for osteoporosis. We studied a population of 220 young women from the city of São Paulo, Brazil, with respect to BMD and its correlation with both COLIA1 genotype and clinical aspects. The distribution of COLIA1 genotype SS, Ss and ss in the population studied was 73.6, 24.1 and 2.3%, respectively. No association between these genotypes and femoral or lumbar spine BMD was detected. There was a positive association between lumbar spine BMD and weight (P<0.0001), height (P<0.0156), and body mass index (BMI) (P<0.0156), and a negative association with age at menarche (P<0.0026). There was also a positive association between femoral BMD and weight (P<0.0001), height (P<0.0001), and BMI (P<0.0001), and a negative correlation with family history for osteoporosis (P<0.041). There was no association between the presence of allele s and reduced BMD. We conclude that a family history of osteoporosis and age at menarche are factors that may influence bone mass in our population.

Fractures are the feared consequences of osteoporosis and fractures of the proximal femur (FPF) are those that involve the highest morbidity and mortality. Thus far, evaluation of bone mineral density (BMD) is the best way to determine the risk of fracture. Genetic inheritance, in turn, is one of the major determinants of BMD. A correlation between different genotypes of the vitamin D receptor (VDR) and BMD has been recently reported. On this basis, we decided to determine the importance of the determination of VDR genotype in the presence of an osteoporotic FPF in a Brazilian population. We studied three groups: group I consisted of 73 elderly subjects older than 65 years (78.5 ± 7.2 years) hospitalized for nonpathological FPF; group II consisted of 50 individuals older than 65 years (72.9 ± 5.2 years) without FPF and group III consisted of 98 young normal Brazilian individuals aged 32.6 ± 6.6 years (mean ± SD). Analysis of VDR gene polymorphism by restriction fragment length polymorphism (RFLP) was performed by PCR amplification followed by BsmI digestion of DNA isolated from peripheral leukocytes. The genotype distribution in group I was 20.5% BB, 42.5% Bb and 37% bb and did not differ significantly from the values obtained for group II (16% BB, 36% Bb and 48% bb) or for group III (10.2% BB, 47.6% Bb and 41.8% bb). No differences in genotype distribution were observed between sexes or between the young and elderly groups. We conclude that determination of VDR polymorphism is of no practical use for the prediction of FPF. Other nongenetic factors probably start to affect bone mass, the risk to fall and consequently the occurrence of osteoporotic fractures with advancing age.