78 research outputs found

    Overcoming inertia : drivers of the outsourcing process

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    Almost all managers have directly or indirectly been involved in the practice of outsourcing in recent years. But as they know, outsourcing is not straightforward. Outsourcing inertia, when companies are slow to adapt to changing circumstances that accommodate higher outsourcing levels, may undermine a firm’s performance. This article investigates the presence of outsourcing inertia and the factors that help managers overcome it. Using statistical evidence, we show that positive performance effects related to outsourcing can accumulate when circumstances change. This is then followed by rapid increases in outsourcing levels (i.e. outsourcing processes). We investigate what gives rise to these outsourcing processes through follow-up interviews with sourcing executives, which suggest five drivers behind outsourcing processes: managerial initiative (using outside experience); hierarchy (foreign headquarters); imitation (of competitors and of similar firms); outsider advice (from external institutions); knowledge sources (using external information). These five drivers all offer scope for managerial action. We tie them to academic literatures and suggest ways of investigating their presence and impact on the outsourcing process. Overall, we conclude that while economizing factors play a key role in explaining how much firms outsource, it is socializing factors that tend to drive outsourcing processes

    Metabolic effects of an entero-omentectomy in mildly obese type 2 diabetes mellitus patients after three years

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    BACKGROUND: Various digestive tract procedures effectively improve metabolic syndrome, especially the control of type 2 diabetes mellitus. Very good metabolic results have been shown with vertical gastrectomy and entero-omentectomy; however, the metabolic effects of an isolated entero-omentectomy have not been previously studied. METHODS: Nine patients with type 2 diabetes mellitus and a body mass index ranging from 29 to 34.8 kg/m² underwent an entero-omentectomy procedure that consisted of an enterectomy of the middle jejunum and exeresis of the major part of the omentum performed through a mini-laparotomy. Glucagon-like peptide-1 and peptide YY were measured preoperatively and three months following the operation. Fasting and postprandial variations in glycemia, insulinemia, triglyceridemia, hemoglobin A1c, and body mass index were determined in the preoperative period and 3, 18 and, 36 months after the operation. RESULTS: All patients significantly improved the control of their type 2 diabetes mellitus. Postprandial secretion of peptide YY and Glucagon-like peptide-1 were enhanced, whereas hemoglobin A1c, fasting and postprandial glucose, insulin, and triglyceride levels were significantly reduced. Mean body mass index was reduced from 31.1 to 27.3 kg/m². No major surgical or nutritional complications occurred. CONCLUSIONS: Entero-omentectomy is easy and safe to perform. A simple reduction in jejunal extension and visceral fat causes important improvements in the metabolic profile

    The karyotypes and evolution of ZZ/ZW sex chromosomes in the genus Characidium (Characiformes, Crenuchidae)

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    Available data on cytotaxonomy of the genus Characidium Reinhardt, 1867, which contains the greatest number of species in the Characidiinae (Crenuchidae), with 64 species widely distributed throughout the Neotropical region, were summarized and reviewed. Most Characidium species have uniform diploid chromosome number (2n) = 50 and karyotype with 32 metacentric (m) and 18 submetacentric (sm) chromosomes. The maintenance of the 2n and karyotypic formula in Characidium implies that their genomes did not experience large chromosomal rearrangements during species diversification. In contrast, the internal chromosomal organization shows a dynamic differentiation among their genomes. Available data indicated the role of repeated DNA sequences in the chromosomal constitution of the Characidium species, particularly, in sex chromosome differentiation. Karyotypes of the most Characidium species exhibit a heteromorphic ZZ/ZW sex chromosome system. The W chromosome is characterized by high rates of repetitive DNA accumulation, including satellite, microsatellite, and transposable elements (TEs), with a varied degree of diversification among species. In the current review, the main Characidium cytogenetic data are presented, highlighting the major features of its karyotype and sex chromosome evolution. Despite the conserved karyotypic macrostructure with prevalent 2n = 50 chromosomes in Characidium, herein we grouped the main cytogenetic information which led to chromosomal diversification in this Neotropical fish group

    Comparative cytogenetics among Leporinus friderici and Leporellus vittatus populations (Characiformes, Anostomidae): focus on repetitive DNA elements

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    Anostomidae are a neotropical fish family rich in number of species. Cytogenetically, they show a conserved karyotype with 2n = 54 chromosomes, although they present intraspecific/interspecific variations in the number and chromosomal location of repetitive DNA sequences. The aim of the present study was to perform a comparative description of the karyotypes of two populations of Leporinus friderici Bloch, 1794 and three populations of Leporellus vittatus Valenciennes, 1850. We used conventional cytogenetic techniques allied to fluorescence in situ hybridization, using 18S ribosomal DNA (rDNA) and 5S rDNA, a general telomere sequence for vertebrates (TTAGGG)n and retrotransposon (RTE) Rex1 probes. The anostomids in all studied populations presented 2n = 54 chromosomes, with a chromosome formula of 32m + 22sm for L. friderici and 28m + 26sm for L. vittatus. Variations in the number and location of the 5S and 18S rDNA chromosomal sites were observed between L. friderici and L. vittatus populations and species. Accumulation of Rex1 was observed in the terminal region of most chromosomes in all populations, and telomere sequences were located just on all ends of the 54 chromosomes in all populations. The intraspecific and intergeneric chromosomal changes occurred in karyotype differentiation, indicating that minor chromosomal rearrangements had present in anostomid species diversification

    Genome Size Evaluation in Tetraodontiform Fishes from the Neotropical Region

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    Abstract Smooth pufferfish of the family Tetraodontidae had become pure genomic models because of the remarkable compaction of their genome. This trait seems to be the result of DNA loss following its divergence from the sister family Diodontidae, which possess larger genomes. In this study, flow cytometry was used for estimate the genome size of four pufferfish species from the Neotropical region. Cytogenetic data and confocal microscopy were also used attempting to confirm relationships between DNA content and cytological parameters. The haploid genome size was 0.71±0.03 pg for Sphoeroides greeleyi, 0.34±0.01 pg for Sphoeroides spengleri, 0.82± 0.03 pg for Sphoeroides testudineus (all Tetraodontidae), and 1.00±0.03 pg for Chilomycterus spinosus (Diodontidae). These differences are not related with ploidy level, because 46 chromosomes are considered basal for both families. The value for S. spengleri represents the smallest vertebrate genome reported to date. Since erythrocyte cell and nuclear sizes are strongly correlated with genome size, the variation in this last is considered under both adaptive and evolutionary perspectives

    Karyotype variability in neotropical catfishes of the family Pimelodidae (Teleostei: Siluriformes)

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    Karyotypic data are presented for four species of fish belonging to the Pimelodidae family. These species show a conserved diploid number, 2n = 56 chromosomes, with different karyotypic formulae. The analyzed species showed little amount of heterochromatin located preferentially in the centromeric and telomeric regions of some chromosomes. The nucleolus organizer regions activity (Ag-NORs) and the chromosomal location of ribosomal genes by fluorescent in situ hybridization (FISH), with 18S and 5S probes, showing only one chromosome pair marked bearer of ribosomal genes, the only exception was Pimelodus britskii that presented multiple NORs and syntenic location of the 18S and 5S probes. Non-Robertsonian events, as pericentric inversion and NORs duplication are requested to explain the karyotype diversification in Pseudoplatystoma from the rio Paraguay (MS), Pimelodus from the rio Iguaçu (PR), Sorubim from the rio Paraguay (MS) and Steindachneridion from the rio Paraíba do Sul (SP). The obtained data for the karyotype macrostructure of these species corroborates a conserved pattern observed in Pimelodidae. On the other hand, interspecific variations detected by molecular cytogenetics markers made possible cytotaxonomic inferences and differentiation of the species here analyzed. Dados cariotípicos são apresentados para quatro espécies da família Pimelodidae. Todas apresentaram o mesmo número diploide, 2n = 56 cromossomos, com diferenças nas fórmulas cariotípicas. As espécies aqui analisadas mostraram pouca quantidade de heterocromatina localizada preferencialmente na região centromérica e telomérica de alguns cromossosmos do complemento cariotípico. As regiões organizadoras de nucléolo (Ag-RONs) e a localização dos genes ribossomais pela hibridização in situ fluorescente (FISH), com sondas 18S e 5S, evidenciaram somente um par cromossômico marcado portador de genes ribossomais, à exceção de Pimelodus britskii que apresentou NORs múltiplas e localização sintênica das sondas 18S e 5S. Eventos não-Robertsonianos, como inversão pericêntrica e duplicação das NORs são requeridos para explicar a diversificação cariotípica em Pseudoplatystoma do rio Paraguai (MS), Pimelodus do rio Iguaçu (PR), Sorubim do rio Paraguai (MS) e Steindachneridion do rio Paraíba do Sul (SP). Os dados obtidos para a macroestrutura cariotípica destas espécies corrobora um padrão conservado observado na família Pimelodidae. Por outro lado, evidências de variações interespecíficas pelos marcadores de citogenética molecular empregados possibilitam inferências citotaxonômicas e diferenciação das espécies aqui analisadas

    Two genetic stocks of steindachneridion melanodermatum living in sympatry in nature and genetic variability of wild parents and F1 generation

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    Steindachneridion melanodermatum is a large Brazilian catfish, highly prized for sport fishing and for its meat. Specimens of this species, both caught in nature from Iguacu River and F1 fish born in captivity, were analyzed with regard to patterns of RAPD molecular markers. Genetic similarity ranged from 0.57 to 0.95; two groups were determined for the wild specimens. The results suggest different genetic lineages in sympatry in nature. Heterozygosity and percentage of polymorphic loci were 0.31 and 79% and 0.23 and 62%, respectively, for the two populations of wild specimens and 0.26 and 66%, respectively, for those born in captivity. © FUNPEC-RP

    Comparative cytogenetics among populations of Astyanax altiparanae (Characiformes, Characidae, Incertae sedis)

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    Cytogenetic data are presented for Astyanax altiparanae populations from three Brazilian hydrographic systems. The chromosomal data obtained in A. altiparanae support the hypothesis of diploid number conservation. However, small differences in the karyotype formula and number of nucleolar organizer regions were observed in these populations. The apparent karyotypical similarity among the studied populations strongly suggests a close relationship among them with some chromosomal divergences due to gene flow restriction

    Repetitive sequences: The hidden diversity of heterochromatin in prochilodontid fish

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    The structure and organization of repetitive elements in fish genomes are still relatively poorly understood, although most of these elements are believed to be located in heterochromatic regions. Repetitive elements are considered essential in evolutionary processes as hotspots for mutations and chromosomal rearrangements, among other functions - thus providing new genomic alternatives and regulatory sites for gene expression. The present study sought to characterize repetitive DNA sequences in the genomes of Semaprochilodus insignis (Jardine & Schomburgk, 1841) and Semaprochilodus taeniurus (Valenciennes, 1817) and identify regions of conserved syntenic blocks in this genome fraction of three species of Prochilodontidae (S. insignis, S. taeniurus, and Prochilodus lineatus (Valenciennes, 1836) by cross-FISH using Cot-1 DNA (renaturation kinetics) probes. We found that the repetitive fractions of the genomes of S. insignis and S. taeniurus have significant amounts of conserved syntenic blocks in hybridization sites, but with low degrees of similarity between them and the genome of P. lineatus, especially in relation to B chromosomes. The cloning and sequencing of the repetitive genomic elements of S. insignis and S. taeniurus using Cot-1 DNA identified 48 fragments that displayed high similarity with repetitive sequences deposited in public DNA databases and classified as microsatellites, transposons, and retrotransposons. The repetitive fractions of the S. insignis and S. taeniurus genomes exhibited high degrees of conserved syntenic blocks in terms of both the structures and locations of hybridization sites, but a low degree of similarity with the syntenic blocks of the P. lineatus genome. Future comparative analyses of other prochilodontidae species will be needed to advance our understanding of the organization and evolution of the genomes in this group of fish. © Maria L. Terencio et al
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