RESUMO
Frullania subgenus Microfrullania is a clade of ca. 15 liverwort species occurring in Australasia, Malesia, and southern South America. We used combined nuclear and chloroplast sequence data from 265 ingroup accessions to test species circumscriptions and estimate the biogeographic history of the subgenus. With dense infra-specific sampling, we document an important role of long-distance dispersal in establishing phylogeographic patterns of extant species. At deeper time scales, a combination of phylogenetic analyses, divergence time estimation and ancestral range estimation were used to reject vicariance and to document the role of long-distance dispersal in explaining the evolution and biogeography of the clade across the southern Hemisphere. A backbone phylogeny for the subgenus is proposed, providing insight into evolution of morphological patterns and establishing the basis for an improved sectional classification of species within Microfrullania. Several species complexes are identified, the presence of two undescribed but genetically and morphologically distinct species is noted, and previously neglected names are discussed.
Assuntos
Frullania/classificação , Australásia , Evolução Biológica , DNA de Plantas/isolamento & purificação , DNA de Plantas/metabolismo , Frullania/anatomia & histologia , Frullania/genética , Loci Gênicos , Filogenia , Filogeografia , Análise de Sequência de DNA , América do SulRESUMO
In the UK, as elsewhere, there is potential to improve how radiological challenges are addressed through improvement in, or development of, a strong radiation protection (RP) safety culture. In preliminary work in the UK, two areas have been identified as having a strong influence on UK society: the healthcare and nuclear industry sectors. Each has specific challenges, but with many overlapping common factors. Other sectors will benefit from further consideration.In order to make meaningful comparisons between these two principal sectors, this paper is primarily concerned with cultural aspects of RP in the working environment and occupational exposures rather than patient doses.The healthcare sector delivers a large collective dose to patients each year, particularly for diagnostic purposes, which continues to increase. Although patient dose is not the focus, it must be recognised that collective patient dose is inevitably linked to collective occupational exposure, especially in interventional procedures.The nuclear industry faces major challenges as work moves from operations to decommissioning on many sites. This involves restarting work in the plants responsible for the much higher radiation doses of the 1960/70s, but also performing tasks that are considerably more difficult and hazardous than those original performed in these plants.Factors which influence RP safety culture in the workplace are examined, and proposals are considered for a series of actions that may lead to an improvement in RP culture with an associated reduction in dose in many work areas. These actions include methods to improve knowledge and awareness of radiation safety, plus ways to influence management and colleagues in the workplace. The exchange of knowledge about safety culture between the nuclear industry and medical areas may act to develop RP culture in both sectors, and have a wider impact in other sectors where exposures to ionising radiations can occur.
Assuntos
Setor de Assistência à Saúde/organização & administração , Promoção da Saúde/organização & administração , Centrais Nucleares , Cultura Organizacional , Guias de Prática Clínica como Assunto , Proteção Radiológica/normas , Gestão da Segurança/organização & administração , Brasil , França , Fidelidade a Diretrizes , Reino UnidoRESUMO
Copying other people's ideas is evaluated negatively by American children and adults. The current study investigated the influence of culture on children's evaluations of plagiarism by comparing children from three countries--the United States, Mexico, and China--that differ in terms of their emphasis on the protection of intellectual property and ideas. Children (3- to 6-year-olds) were presented with videos involving two characters drawing pictures and were asked to evaluate the character who drew unique work or the character who copied someone else's drawing. The study showed that 5- and 6-year-olds from all three cultures evaluated copiers negatively compared with unique drawers. These results suggest that children from cultures that place different values on the protection of ideas nevertheless develop similar concerns with plagiarism by 5-year-olds.
Assuntos
Comparação Transcultural , Plágio , Fatores Etários , Criança , Pré-Escolar , China , Feminino , Humanos , Masculino , México , Psicologia da Criança , Estados UnidosRESUMO
OBJECTIVE: It has recently been reported that up to one-third of patients with nonmetastatic distal rectal cancer managed with neoadjuvant chemoradiation therapy (CRT) had a complete clinical response (cCR) to treatment. In the selected cases, this has been used as the sole treatment. The aim of this study was to determine the frequency of complete pathological response for patients receiving CRT in one centre in the UK. METHOD: Patients receiving 6 weeks of neoadjuvant CRT were identified using the two cancer audit databases in two different tertiary hospitals from January 2002 to November 2007. Pathology was reviewed and the histopathological response of the resected specimen to CRT was evaluated using the Mandard classification (1 = complete response, 5 = no response) RESULTS: One hundred and thirty-two consecutive patients [median age 61 (range 44-86) years, 90 men] with nonmetastatic locally advanced rectal cancer received neoadjuvant chemo radiotherapy between 2002 and 2007 followed by resection of the tumour. Data were available from 129 patients. CONCLUSION: Only 13 out of 132 (10%) of patients had a complete pathological response. This is one-third of the cCR previously reported. Nonsurgical therapy for rectal cancer using the Habr-Gama treatment algorithm may only be effective in a very small proportion of patients with rectal cancer in the UK and nonoperative treatment would not be recommended.
Assuntos
Terapia Neoadjuvante , Neoplasias Retais/tratamento farmacológico , Neoplasias Retais/radioterapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Brasil , Quimioterapia Adjuvante , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Radioterapia Adjuvante , Neoplasias Retais/patologia , Indução de Remissão , Reino UnidoRESUMO
Divergent populations are intrinsically reproductively isolated when hybrids between them either fail to develop properly or do not produce viable offspring. Intrinsic isolation may result from Dobzhansky-Muller (DM) incompatibilities, in which deleterious interactions among genes or gene products lead to developmental problems or underdominant chromosome structure differences between the parents. These mechanisms can be tested by studying marker segregation patterns in a hybrid mapping population. Here we examine the genetic basis of abnormal development in hybrids between two geographically distant populations of the moss Ceratodon purpureus. Approximately half of the hybrid progeny exhibited a severely reduced growth rate in early gametophyte development. We identified four unlinked quantitative trait loci (QTL) that interacted asymmetrically to cause the abnormal development phenotype. This pattern is consistent with DM interactions. We also found an excess of recombination between three marker pairs in the abnormally developing progeny, relative to that estimated in the normal progeny. This suggests that structural differences in these regions contribute to hybrid breakdown. Two QTL coincided with inferred structural differences, consistent with recent theory suggesting that rearrangements may harbor population divergence alleles. These observations suggest that multiple complex genetic factors contribute to divergence among populations of C. purpureus.
Assuntos
Bryopsida/crescimento & desenvolvimento , Bryopsida/genética , Hibridização Genética , Segregação de Cromossomos , Cruzamentos Genéticos , Equador , Marcadores Genéticos , Escore Lod , Modelos Genéticos , Locos de Características Quantitativas , Recombinação GenéticaRESUMO
We report the construction of a linkage map for the moss Ceratodon purpureus (n = 13), based on a cross between geographically distant populations, and provide the first experimental confirmation of maternal chloroplast inheritance in bryophytes. From a mapping population of 288 recombinant haploid gametophytes, genotyped at 121 polymorphic AFLP loci, three gene-based nuclear loci, one chloroplast marker, and sex, we resolved 15 linkage groups resulting in a map length of approximately 730 cM. We estimate that the map covers more than three-quarters of the C. purpureus genome. Approximately 35% of the loci were sex linked, not including those in recombining pseudoautosomal regions. Nearly 45% of the loci exhibited significant segregation distortion (alpha = 0.05). Several pairs of unlinked distorted loci showed significant deviations from multiplicative genotypic frequencies, suggesting that distortion arises from genetic interactions among loci. The distorted autosomal loci all exhibited an excess of the maternal allele, suggesting that these interactions may involve nuclear-cytoplasmic factors. The sex ratio of the progeny was significantly male biased, and the pattern of nonrandom associations among loci indicates that this results from interactions between the sex chromosomes. These results suggest that even in interpopulation crosses, multiple mechanisms act to influence segregation ratios.