RESUMO
Whereas nearly all compounds A(n)B(m) obey Dalton's rule of integer stoichiometry (n: m, both integer), there is a class of systems, exemplified by the rocksalt structure Sc1-x squarexS, that exhibits large deviations from stoichiometry via vacancies, even at low temperatures. By combining first-principles total energy calculations with lattice statistical mechanics, we scan an astronomical number of possible structures, identifying the stable ground states. Surprisingly, all have the same motifs: (111) planes with (112) vacancy rows arranged in (110) columns. Electronic structure calculations of the ground states (identified out of approximately 3x10(6) structures) reveal the remarkable origins of nonstoichiometry.
RESUMO
This article describes a pilot programme initiated in 1991 to address the problems of substance abuse among persons who have experienced traumatic brain injury (TBI). The model of treatment is community-based, using an interdisciplinary staff with expertise in TBI, vocational rehabilitation, and substance abuse treatment, to support and enhance existing services in the client's own community. The primary method of intervention is resource and service coordination. Six principles that serve as the underpinnings of the model are described, as are core and supplemental services and staffing patterns. Innovative components of the programme include the theoretical model of changing addictive behaviours used to guide treatment, and the development of community teams to facilitate a coordinated and integrated approach. The programme has relatively low start-up costs and can serve both urban and rural populations. Clinical experience and initial programme evaluation results suggest that substance abuse and vocational rehabilitation goals can be effectively attained using this model of service delivery.
Assuntos
Dano Encefálico Crônico/reabilitação , Lesões Encefálicas/reabilitação , Equipe de Assistência ao Paciente , Reabilitação Vocacional , Dano Encefálico Crônico/complicações , Dano Encefálico Crônico/psicologia , Lesões Encefálicas/complicações , Lesões Encefálicas/psicologia , Terapia Combinada , Serviços Comunitários de Saúde Mental , Humanos , Planejamento de Assistência ao Paciente , População Rural , População UrbanaRESUMO
Genetic markers were developed for three targeted bovine loci using both single-stranded and double-stranded DNA conformation polymorphisms. Eight of nine DNA fragments exhibited single-stranded conformation polymorphisms while only one of nine exhibited a double-strand conformation polymorphism. All but one of the polymorphic fragments exhibited two allelic forms, with the exception being a single-stranded conformation polymorphism with three alleles. Utility of conformation polymorphisms relative to microsatellite markers for linkage map development and quantitative trait loci (QTL) mapping was assessed by comparing frequency of heterozygote parents from reference and resource families. Heterozygosity was greater for microsatellite markers (P < 0.01) and reference family parents (P < 0.01), though the disparity between marker types tended to be less dramatic for the reference family parents (P < 0.09). These results suggest conformation polymorphisms will be a useful tool for targeted marker development in linkage map and comparative map development provided genetically diverse families are studied.
Assuntos
Bovinos/genética , Marcadores Genéticos , Polimorfismo Genético , Animais , Sequência de Bases , Mapeamento Cromossômico/veterinária , DNA Satélite , Feminino , Heterozigoto , Íntrons , Masculino , Dados de Sequência Molecular , Conformação de Ácido Nucleico , LinhagemAssuntos
Bovinos/genética , DNA de Cadeia Simples/química , Conformação de Ácido Nucleico , Polimorfismo de Fragmento de Restrição , Prolactina/genética , Alelos , Animais , Desoxirribonucleases de Sítio Específico do Tipo II , Feminino , Frequência do Gene , Masculino , Linhagem , Reação em Cadeia da Polimerase/veterináriaAssuntos
Bovinos/genética , DNA Satélite/genética , Polimorfismo Genético , Animais , Sequência de Bases , DNA Satélite/química , DNA de Cadeia Simples/química , Eletroforese em Gel de Poliacrilamida , Feminino , Frequência do Gene , Marcadores Genéticos , Masculino , Dados de Sequência Molecular , Linhagem , Reação em Cadeia da PolimeraseRESUMO
Visual evoked potentials (VEPs) were recorded by chequerboard pattern-reversal stimulation in 276 normal adult subjects aged 15-73 years. The sample comprised comparable white, coloured and black groups of both sexes. Significantly shorter latencies of the major positive component were found in both male and female black subjects compared with those in whites. No significant differences were found between the amplitudes in the different population groups, but females in each population group showed significantly higher amplitudes of the major positive component than males. There was a close relationship between latency and amplitude for both right and left eyes. Except in coloured females, a non-linear relationship of the major positive component with age was demonstrated, the shortest latency being at about 35 years of age. It is suggested that the following criteria be used in the evaluation of VEP recordings: latency as well as the difference between latencies and amplitudes of the two sides of the major positive component (P1) as compared with standardized values for ethnic, sex and age groups.