127 research outputs found

    Catching a Wave: the Adoption of Voice and High Commitment Workplace Practices in Britain: 1984-1998

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    In this paper we treat workplace voice and systems of high-commitment human resource management (HCHRM) as technological innovations in order to account for the uneven diffusion patterns observed across establishments. Using British data, the paper finds that variables highlighted in the technological diffusion literature are significant predictors of voice and HRM adoption decisions. Workplace size, size of multi-establishment network, ownership type, set-up date and network affects all play a significant role in high-commitment HRM adoption. We also find that union presence, per se, is not an inhibitor to the adoption of high commitment HRM practices.High-commitment work practices, voice, unions, technology diffusion,complementarities

    Employee Voice and Private Sector Workplace Outcomes in Britain, 1980-2004

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    Non-union direct voice has replaced union representative voice as the primary avenue for employee voice in the British private sector. This paper provides a framework for examining the relationship between employee voice and workplace outcomes that explains this development. As exit-voice theory predicts, voice is associated with lower voluntary turnover, especially in the case of union voice. Union voice is also associated with greater workplace conflict and poorer productivity. Nonunion voice is associated with better workplace financial performance than other voice regimes.employee voice, trade unions, productivity, industrial action, quits, labor-management relations

    Employee Voice and Human Resource Management: An Empirical Analysis using British Data

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    Using British workplace data we examine the relationship between human resource management (HRM) and different forms of employee voice. After controlling for observable establishment characteristics, we find voice and HRM are positively correlated, but this positive association is confined to certain voice regimes. Previous research has found no association between HRM and union voice. However, distinguishing between union-only voice regimes and dual channel (i.e. union and nonunion) voice regimes reveals that union-only regimes have the lowest incidence and intensity of HRM adoption while dual channel regimes have the highest HRM incidence and intensity. The implications of these findings for theory and practice are discussed.

    Citogenética evolutiva em espécies da família Columbidae (Aves, Columbiformes)

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    Columbidae Ă© uma famĂ­lia da Classe Aves, Ordem Columbiformes que inclui os pombos, pombas e rolas e compreende cerca de 300 espĂ©cies, distribuĂ­da em todos os continentes. Devido a diversidade deste grupo, espĂ©cies desta famĂ­lia foram alvos de vĂĄrios estudos, incluindo citogenĂ©ticos. Apesar de que a maioria dos estudos citogenĂ©ticos em espĂ©cies da famĂ­lia Columbidae foram baseados apenas na citogenĂ©tica clĂĄssica (coloração convencional e bandeamentos cromossĂŽmicos), resultados interessantes foram observados, tais como a variação do nĂșmero diploide e a ocorrĂȘncia de rearranjos intercromossĂŽmicos e intracromossĂŽmicos. Estes estudos influenciaram na escolha da famĂ­lia Columbidae para o desenvolvimento desta Tese. Nas Ășltimas dĂ©cadas houve um grande esforço para reconstruir a filogenia das aves atuais, mas a anĂĄlise dos cariĂłtipos atravĂ©s de tĂ©cnicas de citogenĂ©tica molecular, tais como a pintura cromossĂŽmica ainda limita-se a poucas ordens. Considerando que a Ășltima revisĂŁo dos dados citogenĂ©ticos Ă© de 2007, no capĂ­tulo I realizamos uma revisĂŁo sobre o genoma das Aves, incluindo dados de citogenĂ©tica clĂĄssica e molecular. No capĂ­tulo II nĂłs realizamos a caracterização do cariĂłtipo de nove espĂ©cies da famĂ­lia Columbidae, sendo que uma delas foi descrita pela primeira vez (Geotrygon violacea) e mapeamos a distribuição de sequĂȘncias repetitivas (rDNA 18S e microssatĂ©lites). No capĂ­tulo III realizamos a pintura cromossĂŽmica comparative em quatro espĂ©cies da famĂ­lia Columbidae (Zenaida auriculata, Columba livia, Columbina picui e Leptotila verreauxi). A pintura cromossĂŽmica foi realizada utilizando sondas cromossomo-especĂ­fica de Gallus gallus (GGA), Leucopternis albicollis (LAL) e de Z. auriculata (ZAU). As sondas de ZAU foram desenvolvidas durante o doutorado sanduĂ­che relalizado na Universidade de Cambridge (2017). A pintura cromossĂŽmica com as sondas de GGA e ZAU demonstraram a conservação da maioria dos macrocromossomos, exceto a fusĂŁo entre os cromossomos ancestrais 6 e 7 em L. verreauxi. Entretanto, os sinais de hibridização das sondas de ZAU foram mais intensos do que GGA. As sondas de LAL confirmaram os resultados obtidos com as sondas de GGA e ZAU, mas revelaram tambĂ©m uma complexa reorganização do cromossomo homĂłlogo ao GGA1 nas quatro espĂ©cies analisadas, involvendo inversĂ”es paracĂȘntricas e pericĂȘntricas. AlĂ©m disso, inversĂ”es nos cromossomos homĂłlogos ao GGA2 foram identificadas em C. picui e L. verreauxi. A ocorrĂȘncia da reorganização dos cromossomos homĂłlogos ao GGA1 nas quatro espĂ©cies analisadas neste capĂ­tulo e em espĂ©cies da Ordem Passeriformes analisados previamente, corroboram com a recente proposta de divergĂȘncia das Neoaves (Columbea e Passerea). No capĂ­tulo IV realizamos a pintura cromossĂŽmica com as sondas de ZAU e GGA na espĂ©cie Jacana jacana (Charadriiformes), com o objetivo de verificar a eficiĂȘncia das sondas desenvolvidas durante o doutorado sanduĂ­che. Observamos sinais de hibridização mais intensos para as sondas de ZAU do que GGA, o que diminui o viĂ©s na interpretação dos dados. TambĂ©m identificamos uma extensa reorganização cromossĂŽmica na espĂ©cie J. jacana, que em comparação com dados da literatura, demonstra que espĂ©cies da Ordem Charadriiformes passaram por uma evolução cromossĂŽmica exclusiva. Os resultados desta Tese demonstram que distintos rearranjos ocorreram durante a evolução cromossĂŽmica das espĂ©cies da famĂ­lia Columbidae e tambĂ©m na espĂ©cie J. jacana. AlĂ©m disso, as sondas de ZAU mostraram-se como uma importante ferramente para comparaçÔes cromossĂŽmicas em espĂ©cies de Aves, principalmente Neoaves.Columbidae is a family of Class Aves, Order Columbiformes that includes the pigeons, doves and rolas and comprises about 300 species, distributed in all the continents. Due to the diversity of this group, species of this family were the targets of several studies, including cytogenetics. Although most cytogenetic studies on species of the Columbidae family were based only on classical cytogenetics (conventional staining and chromosomal banding), interesting results were observed, such as diploid number variation and the occurrence of interchromosomal and intrachromosomal rearrangements. These studies influenced the choice of the Columbidae family for the development of this thesis. In recent decades there has been a great effort to reconstruct the phylogeny of current birds, but the analysis of karyotypes through molecular cytogenetic techniques such as chromosome painting is still limited to a few orders. Considering that the last revision of the cytogenetic data is from 2007, in chapter I we conducted a review on the genome of Birds, including classical and molecular cytogenetic data. In chapter II we performed the karyotype characterization of nine species of the Columbidae family, one of which was described for the first time (Geotrygon violacea) and mapped the distribution of repetitive sequences (18S rDNA and microsatellites). In Chapter III we performed comparative chromosome painting on four species of the family Columbidae (Zenaida auriculata, Columba livia, Columbina picui and Leptotila verreauxi). Chromosome painting was performed using chromosome-specific probes from Gallus gallus (GGA), Leucopternis albicollis (LAL) and Z. auriculata (ZAU). The ZAU probes were developed during the “Doutorado sanduiche” at the University of Cambridge (2017). The chromosome painting with GGA and ZAU probes demonstrated the conservation of most of the macrochromosomes except the fusion between the ancestral chromosomes 6 and 7 in L. verreauxi. However, hybridization signals from the ZAU probes were more intense than GGA. LAL probes confirmed the results obtained with the GGA and ZAU probes, but also revealed a complex rearrangement of the chromosome homologous to GGA1 in the four species analyzed, involving paracentric and pericentric inversions. In addition, inversions in chromosomes homologous to GGA2 were identified in C. picui and L. verreauxi. The occurrence of the reorganization of homologous GGA1 chromosomes in the four species analyzed in this chapter and in species of the Passeriformes Order analyzed previously, corroborate with the recent proposal of divergence of the Neoaves (Columbea and Passerea). In chapter IV we performed the chromosome painting with the ZAU and GGA probes in the Jacana jacana (Charadriiformes) species, with the objective of verifying the efficiency of the probes developed during the “Doutorado sanduiche”. We observed more intense hybridization signals for the ZAU probes than GGA, which reduces the bias in the interpretation of the data. We also identified an extensive chromosome reorganization in the J. jacana species, which, in comparison with literature data, shows that species of the Order Charadriiformes underwent a unique chromosomal evolution. The results of this thesis demonstrate that distinct rearrangements occurred during the chromosome evolution of the species of the family Columbidae and also in the species J. jacana. In addition, the ZAU probes proved to be an important tool for chromosome comparisons in species of Birds, especially Neoaves

    Hybridization in canids : a case study of pampas fox (Lycalopex gymnocercus) and domestic dog (Canis lupus familiaris) hybrid

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    Hybridization between species with different evolutionary trajectories can be a powerful threat to wildlife conservation. Anthropogenic activities, such as agriculture and livestock, have led to the degradation and loss of natural habitats for wildlife. Consequently, the incidence of interspecific hybridization between wild and domestic species has increased, although cases involving species of different genera are rare. In Vacaria, a Southern city in Brazil, a female canid with a strange phenotype, which had characteristics between the phenotype of the domestic dog (Canis familiaris) and that of the pampas fox (Lycalopex gymnocercus), was found. Our analysis suggests that the animal is a hybrid between a domestic dog and a pampas fox, but future studies are necessary to investigate additional cases of this hybridization in nature. This finding worries for the conservation of wild canids in South America, especially concerning Lycalopex species. Hybridization with the domestic dog may have harmful effects on pampas fox populations due to the potential for introgression and disease transmission by the domestic dog. Therefore, future studies to explore the consequences of hybridization on genetics, ecology, and behavior of wild populations will be essential to improve the conservation of this species

    Bird’s-eye view of chromosomic evolution in Class Aves

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    Birds (Aves) are the most speciose of terrestrial vertebrates, displaying Class-specific characteristics yet incredible external phenotypic diversity. Critical to agriculture and as model organisms, birds have adapted to many habitats. The only extant examples of dinosaurs, birds emerged ~150 mya and >10% are currently threatened with extinction

    A bird's-eye view of chromosomic evolution in the Class Aves

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    Birds (Aves) are the most speciose of terrestrial vertebrates, displaying Class-specific characteristics yet incredible external phenotypic diversity. Critical to agriculture and as model organisms, birds have adapted to many habitats. The only extant examples of dinosaurs, birds emerged ~150 mya and >10% are currently threatened with extinction. This review is a comprehensive overview of avian genome (“chromosomic”) organization research based mostly on chromosome painting and BAC-based studies. We discuss traditional and contemporary tools for reliably generating chromosome-level assemblies and analyzing multiple species at a higher resolution and wider phylogenetic distance than previously possible. These results permit more detailed investigations into inter- and intrachromosomal rearrangements, providing unique insights into evolution and speciation mechanisms. The ‘signature’ avian karyotype likely arose ~250 mya and remained largely unchanged in most groups including extinct dinosaurs. Exceptions include Psittaciformes, Falconiformes, Caprimulgiformes, Cuculiformes, Suliformes, occasional Passeriformes, Ciconiiformes, and Pelecaniformes. The reasons for this remarkable conservation may be the greater diploid chromosome number generating variation (the driver of natural selection) through a greater possible combination of gametes and/or an increase in recombination rate. A deeper understanding of avian genomic structure permits the exploration of fundamental biological questions pertaining to the role of evolutionary breakpoint regions and homologous synteny blocks

    Karyotype Evolution in Birds: From Conventional Staining to Chromosome Painting.

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    In the last few decades, there have been great efforts to reconstruct the phylogeny of Neoaves based mainly on DNA sequencing. Despite the importance of karyotype data in phylogenetic studies, especially with the advent of fluorescence in situ hybridization (FISH) techniques using different types of probes, the use of chromosomal data to clarify phylogenetic proposals is still minimal. Additionally, comparative chromosome painting in birds is restricted to a few orders, while in mammals, for example, virtually all orders have already been analyzed using this method. Most reports are based on comparisons using Gallus gallus probes, and only a small number of species have been analyzed with more informative sets of probes, such as those from Leucopternis albicollis and Gyps fulvus, which show ancestral macrochromosomes rearranged in alternative patterns. Despite this, it is appropriate to review the available cytogenetic information and possible phylogenetic conclusions. In this report, the authors gather both classical and molecular cytogenetic data and describe some interesting and unique characteristics of karyotype evolution in birds

    Phylogenetic Analysis and Karyotype Evolution in Two Species of Core Gruiformes: Aramides cajaneus and Psophia viridis.

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    Gruiformes is a group with phylogenetic issues. Recent studies based on mitochondrial and genomic DNA have proposed the existence of a core Gruiformes, consisting of five families: Heliornithidae, Aramidae, Gruidae, Psophiidae and Rallidae. Karyotype studies on these species are still scarce, either by conventional staining or molecular cytogenetics. Due to this, this study aimed to analyze the karyotype of two species (Aramides cajaneus and Psophia viridis) belonging to families Rallidae and Psopiidae, respectively, by comparative chromosome painting. The results show that some chromosome rearrangements in this group have different origins, such as the association of GGA5/GGA7 in A. cajaneus, as well as the fission of GGA4p and association GGA6/GGA7, which place P. viridis close to Fulica atra and Gallinula chloropus. In addition, we conclude that the common ancestor of the core Gruiformes maintained the original syntenic groups found in the putative avian ancestral karyotype

    Genomic Organization of Microsatellites and LINE-1- like Retrotransposons: Evolutionary Implications for Ctenomys minutus (Rodentia: Ctenomyidae) Cytotypes

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    Simple Summary In animals, several species contain substantial chromosomal and genomic variation among their populations, but as to what could have driven such diversification is still a puzzle for most cases. Here, we used molecular cytogenetic analysis to expose the main genomic elements involved in the population variation observed in the Neotropical underground rodents of the genus Ctenomys (Rodentia: Ctenomyidae), which harbor the most significant chromosomal variation among mammals (2n = 10 to 2n = 70). These data provide evidence for a correlation between repetitive genomic content and localization of evolutionary breakpoint regions (EBRs) and highlight their direct impact in promoting chromosomal rearrangements. Abstract The Neotropical underground rodents of the genus Ctenomys (Rodentia: Ctenomyidae) comprise about 65 species, which harbor the most significant chromosomal variation among mammals (2n = 10 to 2n = 70). Among them, C. minutus stands out with 45 different cytotypes already identified, among which, seven parental ones, named A to G, are parapatrically distributed in the coastal plains of Southern Brazil. Looking for possible causes that led to such extensive karyotype diversification, we performed chromosomal mapping of different repetitive DNAs, including microsatellites and long interspersed element-1 ( LINE-1 ) retrotransposons in the seven parental cytotypes. Although microsatellites were found mainly in the centromeric and telomeric regions of the chromosomes, different patterns occur for each cytotype, thus revealing specific features. Likewise, the LINE-1 -like retrotransposons also showed a differential distribution for each cytotype, which may be linked to stochastic loss of LINE-1 in some populations. Here, microsatellite motifs (A) 30 , (C) 30 , (CA) 15 , (CAC) 10 , (CAG) 10 , (CGG) 10 , (GA) 15 , and (GAG) 10 could be mapped to fusion of chromosomes 20/17, fission and inversion in the short arm of chromosome 2, fusion of chromosomes 23/19, and different combinations of centric and tandem fusions of chromosomes 22/24/16. These data provide evidence for a correlation between repetitive genomic content and localization of evolutionary breakpoints and highlight their direct impact in promoting chromosomal rearrangements
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