RESUMO
Macroscopic magnets can easily be manipulated and positioned so that interactions between themselves and with external fields induce interesting dynamics and equilibrium configurations. In this work, we use rotating magnets positioned in a line or at the vertices of a regular polygon. The rotation planes of the magnets can be modified at will. The rich structure of stable and unstable configurations is dictated by symmetry and the side of the polygon. We show that both symmetric solutions and their symmetry-breaking bifurcations can be explained with group theory. Our results suggest that the predicted magnetic textures should emerge at any length scale as long as the interaction is polar, and the system is endowed with the same symmetries.
RESUMO
In order to obtain information about the population structure of two black Venezuelan populations with historical differences both in their origins and development, a variety of variables were utilized, especially on marital structure, including: frequency of surnames, isonymy, population genealogical consanguinity, multiple unions, and marital distances, all of which provided information and isolation, migration, endogamy, consanguinity, and patri-matrifocality. Results showed differences in the extent of isolation and endogamy, as well as differences in population structure, which can be directly related with historical conditions of each population. Results agree with those previously obtained with traditional genetic polymorphisms and with the historical information available. Thus, the usefulness of surnames for inferring about population structure is supported, as well as the usefulness of historical information for explaining genetic diversity.
PIP: "In order to obtain information about the population structure of two black Venezuelan populations with historical differences both in their origins and development, a variety of variables were utilized, especially on marital structure, including: frequency of surnames, isonymy, population genealogical consanguinity, multiple unions, and marital distances, all of which provided information and isolation, migration, endogamy, consanguinity, and patri-matrifocality. Results showed differences in the extent of isolation and endogamy, as well as differences in population structure, which can be directly related with historical conditions of each population." (EXCERPT)
Assuntos
População Negra , Etnicidade , Casamento/etnologia , População , Antropologia Cultural , Consanguinidade , Emigração e Imigração , Feminino , Variação Genética , Genética Populacional , Humanos , Masculino , Polimorfismo Genético , Condições Sociais , Isolamento Social , VenezuelaRESUMO
BACKGROUND: Intrauterine growth retardation, associated to hypertensive disease of pregnancy, is responsible for a higher perinatal mortality and morbidity. AIM: To assess obstetrical, perinatal and neonatal features of intrauterine growth retardation associated to hypertensive disease of pregnancy. PATIENTS AND METHODS: One hundred thirty seven newborns with intrauterine growth retardation, whose mothers had hypertensive disease of pregnancy, were compared to 165 similar newborns but whose mothers did not have the disease. RESULTS: The incidence of intrauterine growth retardation associated to hypertensive disease of pregnancy was 45.4%. Maternal obesity at the start and end of pregnancy, a pregestational weight over 65 kg and a weight increment of more than 20 kg during pregnancy were risk factors for hypertensive disease of pregnancy with relative risks of 1.76, 1.62, 1.62 and 2.09 respectively. Relative risks for cesarean section and prematurity were also higher among women with hypertensive disease of pregnancy. Intrauterine growth retardation associated to maternal hypertension was symmetrical and severe in 37.9% of newborns. All seven neonatal deaths occurred in newborns with severe retardation. CONCLUSIONS: Neonatal and perinatal morbidity and mortality are higher in newborns with intrauterine growth retardation. Hypertensive disease of pregnancy was associated with a twice higher incidence of asymmetrical intrauterine growth retardation.
Assuntos
Retardo do Crescimento Fetal/epidemiologia , Retardo do Crescimento Fetal/etiologia , Hipertensão , Complicações Cardiovasculares na Gravidez , Peso ao Nascer , Estudos de Coortes , Estudos Transversais , Eclampsia/epidemiologia , Feminino , Humanos , Incidência , Recém-Nascido , Estado Nutricional , Gravidez , Estudos ProspectivosRESUMO
The population structure of 10 populations ("comunas") in Valparaíso, V Region Chile, was studied through the frequency of consanguineous marriages (%CM) and the coefficient of consanguinity (alpha), in order to know their dynamics, and gather information for clinical and genetic epidemiological studies as well as for isonymy studies. The comunas were grouped according to density: Group I, high density, more than 100 inhabitants/km2; Group II, intermediate, between 25 and 99 inhabitants/km2; and Group III, low, less than 25 inhabitants/km2. Data were obtained from parochial archives and national census, from 1880 to 1969. CM's were divided in: uncle-aunt/nephew-niece (12), first cousins (22), first cousins one removed (23), second cousins (33) and multiple consanguinity (M), and the four subtypes of 12 and 22. Percentage of CM and alpha diminish in time. Groups I and II show similar values, but lower in I, and show a constant decrease. Group III has higher values and considerable fluactuations. Types 12 and 22 contribute mostly to %CM and alpha in the 3 groups. Subtypes of 12 and 22 do not occur at random. This temporary and spatial behavior can be explained because of sociocultural and socioeconomical factors in each group, being density an indicator of endogamy. This behavior is consistent with current coefficients of endogamy obtained by isonymy.
Assuntos
Consanguinidade , Casamento , Densidade Demográfica , Chile , Feminino , Humanos , MasculinoRESUMO
A study on the presence of human papillomavirus (HPV) DNA sequences and focal epithelial hyperplasia (FEH) in a family of Venezuelan ancestry has revealed that FEH is an HPV-induced disease presenting familial aggregation. The genealogical evidence indicates a genetic predisposition to the disease.
Assuntos
Doenças da Boca/genética , Doenças da Boca/microbiologia , Papillomaviridae/patogenicidade , Infecções Tumorais por Vírus/genética , Adolescente , Sondas de DNA de HPV , Feminino , Predisposição Genética para Doença , Humanos , Hiperplasia , Mucosa Bucal/patologia , Linhagem , VenezuelaRESUMO
We describe 27 individuals of 7 families related to each other with high probability who showed manifestations of ectodermal dysplasia and other anomalies affecting females as severely as males with variable expressivity. All parents were normal. These families were detected in a relatively isolated and inbred population with very small neighbouring communities from a Caribbean Sea island, Margarita Island, in Northeastern Venezuela (Nueva Esparta State). The clinical picture common to all patients could not be classified within the heterogeneous group of known ectodermal dysplasias and the published cases do not resemble our patients. We believe that this condition constitutes a newly recognized autosomal recessive dysplasia/malformation syndrome of ectodermal dysplasia.
Assuntos
Displasia Ectodérmica/genética , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Consanguinidade , Displasia Ectodérmica/patologia , Feminino , Genes Recessivos , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Linhagem , Fenótipo , Síndrome , VenezuelaRESUMO
A family of five was examined. Four of them presented with enamel alteration including changes in colour and loss of enamel surface. A genetic study was undertaken which revealed an autosomal dominant inheritance with complete penetration and variable expressivity. This is reflected in shape, number, extension and depth of the affected areas. Amelogénesis Imperfecta type IV was diagnosed using Shields classification.
Assuntos
Amelogênese Imperfeita/genética , Adolescente , Adulto , Criança , Família , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Linhagem , Descoloração de Dente/genéticaRESUMO
A formula for the standard error of Lasker's coefficient of relationship Ri derived from isonymy is proposed, and used to test for differences in relationship in two groups of pairs of spouses from the town of Quibor in Venezuela sampled one century apart. From analysis of the relationship, it was possible to attribute population growth also to immigration. Further, the study of the values of Ri showed that the surnames belonging to the male line are more frequent and stable in this population, which is characterized by a predominantly agricultural activity. From the analysis of the coefficients of relationship, the population of Quibor is also classified as patrilocal.
PIP: Lasker's coefficient of relationship has been used to measure genetic similarity between and within human populations, and to determine the temporal variation of the similarity. A formula for the standard error of Lasker's coefficient of relations Ri derived from isonomy is proposed, and used to test for differences in relationship in 2 groups of pairs of spouses from the town of Quibor in Venezuela sampled 1 century apart. Members of this studied population each have 2 surnames, differing from traditionally studied populations employing the single surname Northern European system. Quibor's 1980 population totaled 22,100, having grown rapidly from its 1940 inhabitant level of 3100. From analysis of the relationship, it was possible to attribute population growth also to immigration. Further, the study of the values of Ri showed that the surnames belonging to the male line are more frequent and stable in this predominantly agricultural population. From the analysis of the coefficients of relationship, the population of Quibor is also classified as patrilocal.
Assuntos
Família , Crescimento Demográfico , Emigração e Imigração , Feminino , Humanos , Masculino , Casamento , Análise de Regressão , VenezuelaRESUMO
The coefficient of relationship by isonymy Ri is a good indicator of similarities between and within populations by means of identity of surnames. In this study we present the results of an analysis of Ri obtained using two surnames for each person in two small Venezuelan populations of African origin: Birongo and La Sabana. The analyses of six Ri values within each population in two periods and of sixteen Ri values within each population between two periods and within each period between populations show that the higher values of Ri are those that include combinations of maternal surnames compared with any other combination and that in one period the relationship between Birongo and La Sabana was equal to 0, as measured with combinations of paternal surnames. These facts are indicators of a tendency toward matrifocal behavior and show that the use of four surnames for estimating Ri permits detailed comparisons of the relationship between and within groups.
Assuntos
Consanguinidade , Família , Genética Populacional , Casamento , Terminologia como Assunto , África/etnologia , Feminino , Humanos , Masculino , VenezuelaRESUMO
A review of the more relevant clinical, radiological, histopathological and genetics aspects of Dentinogenesis imperfecta (DI) is presented, together with the description of a family with DI. The complete analysis of the affected and non-affected members showed that the defect can be classified as a DI type II with an autosomal dominant mode of inheritance with complete penetrance and variable expressivity. Also it is necessary to emphasize the importance of a multidisciplinary approach (Pedodontists, Oral Pathologists and geneticists) in the description, diagnosis and treatment of the individuals affected with DI.