Genetic distance estimated by RAPD markers and its relationship with hybrid performance in maize

The objective of this work was to evaluate the genetic diversity of 16 maize inbred lines, and to determine the correlation between genetic distance and hybrid performance, using random amplified polymorphic DNA (RAPD) molecular markers. Twenty-two different random primers were used, which resulted in the amplification of 265 fragments, 237 (84.44%) of them being polymorphic. A genetic similarity matrix was created from the RAPD data, using Jaccard coefficient, and a dendrogram was constructed. Hybrid analyses were carried out using random block design and Griffing method VI for diallel crossings. The genetic associations showed five distinct heterotic groups. Correlations between genetic divergences detected by RAPD, as well as the means observed in the diallel crossings were positive and significant for plant height, ear height, prolificacy, and grain weight. The correlation of genetic divergences, detected by RAPD, and the specific combining ability between heterotic group associations, showed significance in all characteristics under study, except prolificacy. A direct relationship between genetic divergence and productivity was found in 79.2% of the 120 hybrids confirming the hypothesis that genetic divergence is directly related to the performance of hybrids and is efficient in predicting it.

Genetic origin of the relationship between parental negativity and behavior problems from early childhood to adolescence: A longitudinal genetically sensitive study.

Little is known about how genetic and environmental factors contribute to the association between parental negativity and behavior problems from early childhood to adolescence. The current study fitted a cross-lagged model in a sample consisting of 4,075 twin pairs to explore (a) the role of genetic and environmental factors in the relationship between parental negativity and behavior problems from age 4 to age 12, (b) whether parent-driven and child-driven processes independently explain the association, and (c) whether there are sex differences in this relationship. Both phenotypes showed substantial genetic influence at both ages. The concurrent overlap between them was mainly accounted for by genetic factors. Causal pathways representing stability of the phenotypes and parent-driven and child-driven effects significantly and independently account for the association. Significant but slight differences were found between males and females for parent-driven effects. These results were highly similar when general cognitive ability was added as a covariate. In summary, the longitudinal association between parental negativity and behavior problems seems to be bidirectional and mainly accounted for by genetic factors. Furthermore, child-driven effects were mainly genetically mediated, and parent-driven effects were a function of both genetic and shared-environmental factors.

Directional dominance on stature and cognition in��diverse human populations.

Homozygosity has long been associated with rare, often devastating, Mendelian disorders, and Darwin was one of the first to recognize that inbreeding reduces evolutionary fitness. However, the effect of the more distant parental relatedness that is common in modern human populations is less well understood. Genomic data now allow us to investigate the effects of homozygosity on traits of public health importance by observing contiguous homozygous segments (runs of homozygosity), which are inferred to be homozygous along their complete length. Given the low levels of genome-wide homozygosity prevalent in most human populations, information is required on very large numbers of people to provide sufficient power. Here we use runs of homozygosity to study 16 health-related quantitative traits in 354,224 individuals from 102 cohorts, and find statistically significant associations between summed runs��of homozygosity and four complex traits: height, forced expiratory lung volume in one second, general cognitive ability and educational attainment (P < 1 �� 10(-300), 2.1 �� 10(-6), 2.5 �� 10(-10) and 1.8 �� 10(-10), respectively). In each case, increased homozygosity was associated with decreased trait value, equivalent to the offspring of first cousins being 1.2 cm shorter and having 10 months' less education. Similar effect sizes were found across four continental groups and populations with different degrees of genome-wide homozygosity, providing evidence that homozygosity, rather than confounding, directly contributes to phenotypic variance. Contrary to earlier reports in substantially smaller samples, no evidence was seen of an influence of genome-wide homozygosity on blood pressure and low density lipoprotein cholesterol, or ten other cardio-metabolic traits. Since directional dominance is predicted for traits under directional evolutionary selection, this study provides evidence that increased stature and cognitive function have been positively selected in human evolution, whereas many important risk factors for late-onset complex diseases may not have been.

In vitro culture and characterization of alveolar bone osteoblasts isolated from type 2 diabetics

In order to understand the mechanisms of poor osseointegration following dental implants in type 2 diabetics, it is important to study the biological properties of alveolar bone osteoblasts isolated from these patients. We collected alveolar bone chips under aseptic conditions and cultured them in vitro using the tissue explants adherent method. The biological properties of these cells were characterized using the following methods: alkaline phosphatase (ALP) chemical staining for cell viability, Alizarin red staining for osteogenic characteristics, MTT test for cell proliferation, enzyme dynamics for ALP contents, radio-immunoassay for bone gla protein (BGP) concentration, and ELISA for the concentration of type I collagen (COL-I) in the supernatant. Furthermore, we detected the adhesion ability of two types of cells from titanium slices using non-specific immunofluorescence staining and cell count. The two cell forms showed no significant difference in morphology under the same culture conditions. However, the alveolar bone osteoblasts received from type 2 diabetic patients had slower growth, lower cell activity and calcium nodule formation than the normal ones. The concentration of ALP, BGP and COL-I was lower in the supernatant of alveolar bone osteoblasts received from type 2 diabetic patients than in that received from normal subjects (P < 0.05). The alveolar bone osteoblasts obtained from type 2 diabetic patients can be successfully cultured in vitro with the same morphology and biological characteristics as those from normal patients, but with slower growth and lower concentration of specific secretion and lower combining ability with titanium than normal ones.

Beyond g : putting multiple intelligences theory to the test /

The purpose of this study was to investigate Howard Gardner's (1983) Multiple Intelligences theory, which proposes that there are eight independent intelligences: Linguistic, Spatial, Logical/Mathematical, Interpersonal, Intrapersonal, Naturalistic, Bodily-Kinesthetic, and Musical. To explore Gardner's theory, two measures of each ability area were administered to 200 participants. Each participant also completed a measure of general cognitive ability, a personality inventory, an ability self-rating scale, and an ability self-report questionnaire. Nonverbal measures were included for most intelligence domains, and a wide range of content was sampled in Gardner's domains. Results showed that all tests of purely cognitive abilities were significantly correlated with the measure of general cognitive ability, whereas Musical, Bodily-Kinesthetic, and one of the Intrapersonal measures were not. Contrary to what Multiple Intelligences theory would seem to predict, correlations among the tests revealed a positive manifold and factor analysis indicated a large factor of general intelligence, with a mathematical reasoning test and a classification task from the Naturalistic domain having the highest ^- loadings. There were only minor sex differences in performance on the ability tests. Participants' self-estimates of ability were significantly and positively correlated with actual performance in some, but not all, intelligences. With regard to personality, a hypothesized association between Openness to Experience and crystallized intelligence was supported. The implications of the findings in regards to the nature of mental abilities were discussed, and recommendations for further research were made.

Novices' learning from the Internet : an exploration of navigation behaviours, learner-related factors, and mental effort

The current study was an exploration of why some novices are more successful than their peers when learning from the Internet by examining the relations among time spent with relevant information and changes in invested mental effort during Internet navigations as well as achievement. Navigation behaviours and learner characteristics were investigated as predictors of time spent with relevant information and changes in mental effort. Undergraduates (N = 85, Mage = 20 years, 5 months) searched the Internet for information corresponding to a low knowledge topic for 20 min while their eye gaze and pupil size were recorded. Pupil diameter was used as an objective, continuous measure of mental effort. Participants also completed questionnaires or computer tasks pertaining to s e l f-regulated learning characteristics (general intrinsic goal orientation and effort regulation) and cognitive factors (working memory control, distractibility and cognitive style). All analyses controlled for general mental ability, reading comprehension, topic and Internet knowledge, and overall motivation. A greater proportion of time spent with relevant information predicted higher scores on an achievement test. Interestingly, time spent with relevant information partially mediated the positive relation between the frequency of increases in invested mental effort and achievement. Surprisingly, intrinsic goal orientation was negatively related to time spent with relevant information and effort regulation was negatively related to the frequency of increases in invested mental effort. These findings have implications for supports when novices guide their own learning, especially when using the Internet.

Cross-resistance following artificial selection for increased defense against parasitoids in Drosophila melanogaster

An increase in resistance to one natural enemy may result in no correlated change, a positive correlated change, or a negative correlated change in the ability of the host or prey to resist other natural enemies. The type of specificity is important in understanding the evolutionary response to natural enemies and was studied here in a Drosaphila-parasitoid system. Drosophila melanogaster lines selected for increased larval resistance to the endoparasitoid wasps Asobara tabida or Leptopilina boulardi were exposed to attack by A. tabida, L. boulardi and Leptopilina heterotama at 15 degrees C, 20 degrees C, and 25 degrees C. In general, encapsulation ability increased with temperature, with the exception of the lines selected against L. boulardi, which showed the opposite trend. Lines selected against L, boulardi showed large increases in resistance against all three parasitoid species, and showed similar levels of defense against A. tabida to the lines selected against that parasitoid. In contrast, lines selected against A. tabida showed a large increase in resistance to A. tabida and generally to L. heterotoma, but displayed only a small change in their ability to survive attack by L. boulardi. Such asymmetries in correlated responses to selection for increased resistance to natural enemies may influence host-parasitoid community structure.

Ensaios sobre ciclos de neg��cios

O objetivo central desse artigo �� o de propor e avaliar modelos econom��tricos de previs��o para o PIB industrial brasileiro. Para tanto, foram utilizados diversos modelos de previs��o como tamb��m combina����es de modelos. Foi realizada uma analise criteriosa das s��ries a serem utilizadas na previs��o. N��s conclu��mos que a utiliza����o de vetores de cointegra����o melhora substancialmente a performance da previs��o. Al��m disso, os modelos de combina����o de previs��o, na maioria dos casos, tiveram uma performance superior aos demais modelos, que j�� apresentavam boa capacidade preditiva.

Potencial heter��tico de linhagens S3 e S4 de milho (Zea mays L.) para obten����o de h��bridos

Conselho Nacional de Desenvolvimento Cient��fico e Tecnol��gico (CNPq)

Cruzamentos entre linhagens tropicais de milho doce e testadores com introgress��o de germoplasma temperado

P��s-gradua����o em Agronomia (Horticultura) - FCA

Potencial de linhagens experimentais de milho (Zea mays L.) para produ����o de h��bridos

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Heterose e capacidade combinat��ria em mel��o rendilhado

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Estimativas de heterose e capacidades de combina����o em cebola para resist��ncia a raiz rosada

P��s-gradua����o em Agronomia (Prote����o de Plantas) - FCA

Comportamento de oviposi����o em Chrysomya megacephala (F.) (Diptera: Calliphoridae): distin����o quantitativa frente a posturas pr��vias?

Chrysomya megacephala (Fabricius), has considerable medical, veterinary and forensic importance. In insects in general, the ability to track the food substrate is due to highly sensitive organs adapted for detecting odors, particularly in the case of blowflies, which is one of carcass main consumers. Eggs of blowflies are usually aggregated in function of the behavior of other pheromone mediated by females laying eggs in place on the same substrate. One of the main reasons for studying oviposition behavior is because it may indirectly affect individual qualification, population dynamics and community structure. It has been suggested that female blowflies can evaluate the number of eggs on a substrate, decreasing the size of oviposition in very saturated substrates with larvae or eggs leading to a lower intraspecific competition. The present study investigated the oviposition behavior of females of C. megacephala, and wished to consider whether they are able to distinguish quantitatively (size of the mass) eggs previously put into a place of posture and hence indicate whether there is a limit beneficial (to avoid competition among larvae) for its oviposition on the same substrate or if that place would already be saturated, requiring find another substrate without eggs or less for futures ovipositions. With 20 females and five males, five treatments were applied, repeated ten times and analyzed using the Mann-Whitney test. Each treatment consists in placing, inside the cage, a flask with 50g of ground beef and another one in the other side, with the same amount of substrate with a certain amount of prior oviposition for a period of 5 hours. The masses prior eggs were used 0.03 g, 0.05 g, 0.1 g, 0.2 g and 0.3 g (respectively, T1, T2, T3, T4 and T5). The other part of the work consisted in the use of a ���Y��� olfactometer, a device used to determine the choice of an invertebrate against... (Complete abstract click electronic access below)

Efeitos g��nicos de caracteres associados �� efici��ncia no uso de nitrog��nio em milho

Os��objetivos��deste��trabalho��foram��determinar��o��controle��gen��tico��da��efici��ncia��no��uso��do��nitrog��nio��(EUN),��identificar��a��import��ncia��das��efici��ncias��na��absor����o��(EAN)��e��na��utiliza����o��(EUtN)��na��sua��composi����o,�� e��quantificar��rela����o��entre��produ����o��de��mat��ria��seca��da��parte��a��rea��(MPS)��e��do��sistema��radicular��com��a��EUN��e�� com��seus��componentes.��Foram��avaliadas��41��combina����es��h��bridas��em��duas��disponibilidades��de��N:��baixa��(BN)�� e��alta��(AN).��Utilizou-se��o��delineamento��de��blocos��ao��acaso��com��duas��repeti����es,��em��arranjo��fatorial��simples�� (combina����o��h��brida��x��disponibilidade��de��N).��As��an��lises��estat��sticas��foram��realizadas��por��meio��das��equa����es�� de��modelos��mistos.��Correla����es��de��elevada��magnitude��foram��detectadas��entre��EAN��e��EUN,��bem��como��entre�� essas��efici��ncias��e��a��MPS,��tanto��em��BN��como��em��AN.��Em��ambas��as��disponibilidades��de��N,��efeitos��gen��ticos�� aditivos��apresentaram��maior��import��ncia��para��os��caracteres��associados������EUN.��Dessa��forma,��a��sele����o��baseada�� no��desempenho��individual��de��linhagens��quanto������MPS��pode��possibilitar��a��obten����o��de��gen��tipos��com��alta�� EUN.��Independentemente��da��disponibilidade��de��N,��a��EAN������o��componente��mais��importante��da��EUN.