Castores: ¿un riesgo de invasión que inquieta a la Patagonia norte?

Las especies exóticas invasoras constituyen una de las amenazas más serias para la biodiversidad, siendo la segunda causa de extinción de especies, precedida tan sólo por la pérdida de hábitat. La introducción del castor en Tierra del ruego hace setenta años, ha sido probablemente el mayor cambio experimentado por los bosques y cuencas fueguinas. Si bien la mayoría de las especies introducidas no se establece de manera permanente o tiene muy pocos efectos sobre los ecosistemas, muchas otras especies sí lo hacen y su impacto generalmente resulta perjudicial, aunque puede ser sumamente variable según el ambiente. Son estas últimas especies las que en la mayoría de los casos se transforman en invasoras, tal como ocurrió con la introducción del castor (Castor canadensis) en Tierra del ruego.Fil: Fasanella, Mariana. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; ArgentinaFil: Lizarralde, Marta Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin

Historical demography and spatial genetic structure of the subterranean rodent <i>Ctenomys magellanicus</i> in Tierra del Fuego (Argentina)

Ctenomys (tuco-tuco) is the most numerous genus of South American subterranean rodents and one of the most genetically diverse clades of mammals known. In particular, the genus constitutes a very interesting model for evolutionary studies of genetic divergence and conservation. Ctenomys magellanicus is the southernmost species of the group and the only one living in Isla Grande de Tierra del Fuego (Argentina). This species presents two chromosomal forms (Cm34 and Cm36) fragmented into demes distributed from the north region (steppe) to the south region (ecotone) of the island, respectively; no hybrids or overlapping areas were detected. To study the historical demography and the spatial genetic structure of the C.magellanicus population we used mitochondrial DNA (mtDNA) (D-loop and cytochrome b) and microsatellite loci. Nine mtDNA haplotypes were identified, three of them belonging to the north and the other six to the south. Shared haplotypes between regions were not detected. mtDNA and microsatellite genotypes showed a marked pattern of population structure with low values of genetic flow between regions. The south is made up of small populations or isolated demes making up an endogamic metapopulation with unique alleles and haplotypes. Also, the results suggest a northward expansion process starting from an ancestral haplotype from the south. That population might have lived at a refuge through the adverse Pleistocene environmental conditions that took place at Tierra del Fuego. Results of this study are relevant to the conservation of C.magellanicus, suggesting that each region (north and south) might be considered as an Evolutionarily Significant Unit.Centro Regional de Estudios Genómico

Evolutionary Genetics of Invasive Mammal Species Introduced in Argentina

Evolutionary genetics of invasive species has been unexplored in Argentina. Invasive alienspecies (IAS) have a wide geographical distribution, characteristic life cycles and great abilityto adapt, establish and spread in a new environment. Recent advances in novel moleculartechnologies, the use of higher resolution genetic markers, and the research development ongenetic variation of invasive species consolidated the importance of genetic aspects in theinvasion process. Undoubtedly, the growing concern for the disturbances generated by invasivespecies on biodiversity and functioning of ecosystems was also determinant for theinclusion of the Invasion Biology within the broad field of Evolutionary Biology includingrelevant examples that address the evolutionary genetic aspects of biological invasions. Recentstudies suggest that the invasion success of many species depends on their ability torespond to natural selection. Although the number of invasive species registered in Argentinafar exceeds 600, little research has been done on invasive mammal species and only fiveof them were hitherto genetically analyzed. Presuming that invasion genetics is incorporatedinto the agenda of control and management organizations, it would allow integrating theecological, genetic, and evolutionary biology aspects for knowledge of invasive specieswidely distributed in Argentina. The objective of this article is to highlight the importanceof evaluating the genetic structure of invasive species for their management and to informabout the invasive species of mammals that were introduced in Argentina and have been orare being analyzed genetically.Fil: Lizarralde, Marta Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Universidad Nacional de La Plata. Centro Regional de Estudios Genómicos; ArgentinaFil: Fasanella, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Ecotono; ArgentinaFil: Poljak, Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Ecotono; Argentina. Universidad Nacional de Tierra del Fuego. Instituto de Ciencias Polares, Recursos Naturales y Ambiente; ArgentinaFil: Gabrielli, Magali. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Centro Regional de Estudios Genómicos; ArgentinaFil: Sánchez, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Ecotono; Argentina. Universidad Nacional de Tierra del Fuego. Instituto de Ciencias Polares, Recursos Naturales y Ambiente; Argentin

Evolutionary Genetics of Invasive Mammal Species Introduced in Argentina

Evolutionary genetics of invasive species has been unexplored in Argentina. Invasive alienspecies (IAS) have a wide geographical distribution, characteristic life cycles and great abilityto adapt, establish and spread in a new environment. Recent advances in novel moleculartechnologies, the use of higher resolution genetic markers, and the research development ongenetic variation of invasive species consolidated the importance of genetic aspects in theinvasion process. Undoubtedly, the growing concern for the disturbances generated by invasivespecies on biodiversity and functioning of ecosystems was also determinant for theinclusion of the Invasion Biology within the broad field of Evolutionary Biology includingrelevant examples that address the evolutionary genetic aspects of biological invasions. Recentstudies suggest that the invasion success of many species depends on their ability torespond to natural selection. Although the number of invasive species registered in Argentinafar exceeds 600, little research has been done on invasive mammal species and only fiveof them were hitherto genetically analyzed. Presuming that invasion genetics is incorporatedinto the agenda of control and management organizations, it would allow integrating theecological, genetic, and evolutionary biology aspects for knowledge of invasive specieswidely distributed in Argentina. The objective of this article is to highlight the importanceof evaluating the genetic structure of invasive species for their management and to informabout the invasive species of mammals that were introduced in Argentina and have been orare being analyzed genetically.Centro Regional de Estudios Genómico

Historical demography and spatial genetic structure of the subterranean rodent <i>Ctenomys magellanicus</i> in Tierra del Fuego (Argentina)

Ctenomys (tuco-tuco) is the most numerous genus of South American subterranean rodents and one of the most genetically diverse clades of mammals known. In particular, the genus constitutes a very interesting model for evolutionary studies of genetic divergence and conservation. Ctenomys magellanicus is the southernmost species of the group and the only one living in Isla Grande de Tierra del Fuego (Argentina). This species presents two chromosomal forms (Cm34 and Cm36) fragmented into demes distributed from the north region (steppe) to the south region (ecotone) of the island, respectively; no hybrids or overlapping areas were detected. To study the historical demography and the spatial genetic structure of the C.magellanicus population we used mitochondrial DNA (mtDNA) (D-loop and cytochrome b) and microsatellite loci. Nine mtDNA haplotypes were identified, three of them belonging to the north and the other six to the south. Shared haplotypes between regions were not detected. mtDNA and microsatellite genotypes showed a marked pattern of population structure with low values of genetic flow between regions. The south is made up of small populations or isolated demes making up an endogamic metapopulation with unique alleles and haplotypes. Also, the results suggest a northward expansion process starting from an ancestral haplotype from the south. That population might have lived at a refuge through the adverse Pleistocene environmental conditions that took place at Tierra del Fuego. Results of this study are relevant to the conservation of C.magellanicus, suggesting that each region (north and south) might be considered as an Evolutionarily Significant Unit.Centro Regional de Estudios Genómico

Evaluation of flow cytometry for the detection of bacteria in biological fluids

Objectives: Conventional microbiological procedures for the isolation of bacteria from biological fluids consist of culture on solid media and enrichment broth. However, these methods can delay the microbiological identification for up to 4 days. The aim of this study was to evaluate the analytical performance of Sysmex UF500i (Sysmex, Kobe, Japan) as a screening method for the detection of bacteria in different biological fluids in comparison with direct Gram staining and the conventional culture on solid media and enrichment broth. Methods: A total of 479 biological fluid samples were included in the study (180 ascitic, 131 amniotic, 56 synovial, 40 cerebrospinal, 36 pleural, 24 peritoneal, 9 bile and 3 pericardial fluids). All samples were processed by conventional culture methods and analyzed by flow cytometry. Direct Gram staining was performed in 339 samples. The amount of growth on culture was recorded for positive samples. Results: Bacterial and white blood cell count by flow cytometry was significantly higher among culture positive samples and samples with a positive direct Gram stain compared to culture negative samples. Bacterial count directly correlated with the amount of growth on culture (Kruskall-Wallis H χ2(3) = 11.577, p = 0.009). The best specificity (95%) for bacterial count to predict culture positivity was achieved applying a cut-off value of 240 bacteria/μL. Conclusions: Bacterial and white blood cell counts obtained with flow cytometry correlate with culture results in biological fluids. Bacterial count can be used as a complementary method along with the direct Gram stain to promptly detect positive samples and perform other diagnostic techniques in order to accelerate the bacterial detection and identification

Measurement of differential cross sections for top quark pair production using the lepton plus jets final state in proton-proton collisions at 13 TeV

National Science Foundation (U.S.

Particle-flow reconstruction and global event description with the CMS detector

The CMS apparatus was identified, a few years before the start of the LHC operation at CERN, to feature properties well suited to particle-flow (PF) reconstruction: a highly-segmented tracker, a fine-grained electromagnetic calorimeter, a hermetic hadron calorimeter, a strong magnetic field, and an excellent muon spectrometer. A fully-fledged PF reconstruction algorithm tuned to the CMS detector was therefore developed and has been consistently used in physics analyses for the first time at a hadron collider. For each collision, the comprehensive list of final-state particles identified and reconstructed by the algorithm provides a global event description that leads to unprecedented CMS performance for jet and hadronic tau decay reconstruction, missing transverse momentum determination, and electron and muon identification. This approach also allows particles from pileup interactions to be identified and enables efficient pileup mitigation methods. The data collected by CMS at a centre-of-mass energy of 8 TeV show excellent agreement with the simulation and confirm the superior PF performance at least up to an average of 20 pileup interactions

Identification of heavy-flavour jets with the CMS detector in pp collisions at 13 TeV

Many measurements and searches for physics beyond the standard model at the LHC rely on the efficient identification of heavy-flavour jets, i.e. jets originating from bottom or charm quarks. In this paper, the discriminating variables and the algorithms used for heavy-flavour jet identification during the first years of operation of the CMS experiment in proton-proton collisions at a centre-of-mass energy of 13 TeV, are presented. Heavy-flavour jet identification algorithms have been improved compared to those used previously at centre-of-mass energies of 7 and 8 TeV. For jets with transverse momenta in the range expected in simulated $\mathrm{t}\overline{\mathrm{t}}$ events, these new developments result in an efficiency of 68% for the correct identification of a b jet for a probability of 1% of misidentifying a light-flavour jet. The improvement in relative efficiency at this misidentification probability is about 15%, compared to previous CMS algorithms. In addition, for the first time algorithms have been developed to identify jets containing two b hadrons in Lorentz-boosted event topologies, as well as to tag c jets. The large data sample recorded in 2016 at a centre-of-mass energy of 13 TeV has also allowed the development of new methods to measure the efficiency and misidentification probability of heavy-flavour jet identification algorithms. The heavy-flavour jet identification efficiency is measured with a precision of a few per cent at moderate jet transverse momenta (between 30 and 300 GeV) and about 5% at the highest jet transverse momenta (between 500 and 1000 GeV)

Search for heavy resonances decaying to a top quark and a bottom quark in the lepton+jets final state in proton–proton collisions at 13 TeV

info:eu-repo/semantics/publishe