Age estimation through skeletochronology and mark-recapture of free-living Liolaemus leopardinus (Squamata: Liolaemidae) from Chile

Estimativa etária por meio de esqueletocronologia e marcação-e-recaptura de Liolaemus leopardinus (Squamata: Liolaemidae) do Chile. A determinação etária é um componente crucial de estudos ecológicos. Pesquisadores tem usado diferentes técnicas e métodos como marcação-erecaptura, tamanho do corpo e esqueletocronologia, para avaliar a idade de indivíduos na natureza. Usamos esses três métodos para estimar a estrutura etária de uma população de Liolaemus leopardinus, uma espécie de lagarto saxícola, altamente social e endêmica da região temperada do centro do Chile. Essa espécie secretiva de grandes altitudes é considerada ameaçada, e apesar dos esforços para descobrir detalhes específcos sobre a sua história natural, detalhes cruciais de sua biologia permanecem desconhecidos. Nosso objetivo foi associar o número de Linhas de Crescimento (LAGs) ao comprimento rostro-cloacal (SVL) e usar as LAGs para representar uma estimativa etária dos indivíduos na natureza. Para as análises de esqueletocronologia, foi coletada uma combinação de cortes de artelhos quando cada indivíduo foi capturado pela primeira vez em 2012–2013. O SVL de todos os indivíduos capturados foi registrado durante duas campanhas consecutivas (primavera a outono de 2011–2012 e 2012–2013). Os dados de SVL estiveram também disponíveis para 10 indivíduos coletados anteriormente e marcados de forma permanante em 2005 (um juvenil e nove adultos) e recapturados em 2011–2012. Três daqueles 10 indivíduos foram capturados novamente em 2012–2013. Nossos resultados revelaram a formação de LAGs em L. leopardinus e um alto grau de remodelação óssea tanto nos junevis como nos adultos. Essa remodelação ósssea combinada com a alta aproximação das LAGs periféricas nas amostras dos lagartos mais velhos sugere que os ossos das falanges não são adequados para a determinação etária nessa espécie. Por outro lado, nossos resultados de marcação-e-recaptura permitiram classifcar os indivíduos em quatro diferentes classes etárias quando o SVL de um indivíduo era associado com os períodos de atividade e recapturas. Indivíduos de L. leopardinus são longevos, podendo exceder uma década. As fêmeas tornam-se sexualmente maduras aos três ou quatro anos de idade.Age estimation through skeletochronology and mark-recapture of free-living Liolaemus leopardinus (Squamata: Liolaemidae) from Chile. Age determination is a crucial component of ecological studies. Researchers have relied on different methods and techniques, for example mark-recapture, body size, and skeletochronology, to assess the age of free-ranging individuals. We used all three methods to estimate the age structure of a population of Liolaemus leopardinus, a highly social and saxicolous lizard species endemic to the temperate region of central Chile. This high-elevation and secretive species is considered threatened and, although efforts have been made to reveal more specifc details about the species’ natural history, crucial details of its biology are still unknown. Our goal was to associate the number of Lines of Arrested Growth (LAGs) to snout–vent length (SVL) and use LAGs as an age estimation proxy on free-ranging individuals. For the skeletochronology analyses, a combination of toe-clips was collected when each subject was frst captured in 2012–2013. SVL for all captured individuals was recorded during two different feld seasons (austral spring to fall of 2011–2012 and 2012–2013). SVL data were also available for 10 individuals initially collected and permanently marked in 2005 (one juvenile and nine adults) and recaptured in 2011–2012. Three of those 10 subjects were captured again in 2012–2013. Our results revealed the formation of LAGs in L. leopardinus and a high degree of bone remodeling in both juveniles and adults. This bone remodeling combined with the high rapprochement in peripheral LAGs on the samples of the oldest lizards suggest that phalangeal bones are not suitable for age determination in this species. On the other hand, our mark-recapture results allowed us to assign individuals to four different age-classes when a subject’s SVL was associated with activity periods and recaptures. Individuals of L. leopardinus are long-lived and their lifespan can exceed a decade. Female lizards become sexually mature at three to four years of age

Search for direct production of charginos, neutralinos and sleptons in final states with two leptons and missing transverse momentum in pp collisions at √s = 8TeV with the ATLAS detector

Searches for the electroweak production of charginos, neutralinos and sleptons in final states characterized by the presence of two leptons (electrons and muons) and missing transverse momentum are performed using 20.3 fb−1 of proton-proton collision data at s√ = 8 TeV recorded with the ATLAS experiment at the Large Hadron Collider. No significant excess beyond Standard Model expectations is observed. Limits are set on the masses of the lightest chargino, next-to-lightest neutralino and sleptons for different lightest-neutralino mass hypotheses in simplified models. Results are also interpreted in various scenarios of the phenomenological Minimal Supersymmetric Standard Model

Structure of concanavalin A at pH 8: bound solvent and crystal contacts

9 pages, 3 figures, 4 tables.Concanavalin A has been crystallized in the presence of the ligand (6-S-[beta]-D-galactopyranosyl-6-thio)-cyclomaltoheptaose. The crystals are isomorphous to those reported for ConA complexed with peptides at low resolution (3.00-2.75 Å). The structure was solved at 1.9 Å, with free R and R values of 0.201 and 0.184, respectively. As expected, no molecules of the ligand were bound to the protein. Soaking in the cryobuffer left its fingerprint as 25 molecules of glycerol in the bound solvent, most of them at specific positions. The fact that a glycerol molecule is located in the sugar-binding pocket of each of the four subunits in the asymmetric unit and another is located in two of the peptide-binding sites suggests a recognition phenomenon rather than a displacement of water molecules by glycerol. Crystal contact analysis shows that a relation exists between the residues that form hydrogen bonds to other asymmetric units and the space group: contact Asp58-Ser62 is a universal feature of ConA crystals, while Ser66-His121, Asn69-Asn118 and Tyr100-His205 contacts are general features of the C2221 crystal form.We thank Professor GarcõÂa-Ruiz for his constant support and helpful discussions and suggestions, Dr Cartwright for reviewing the manuscript and Professor Kabsch for providing XDS free of charge.We acknowledge EMBO/DESY for beam time, Professor Martinez Ripoll for his kind support in the preliminary X-ray characterization using the rotating-anode generator at the Instituto de QuõÂmica Fisica Roca Solano (CSIC) and the referees for valuable comments.Work in AA's laboratory is funded by Spanish Plan Nacional grant BMC- 2002-04011-C03.Peer reviewe

Measurement of the production of a W boson in association with a charm quark in pp collisions at √s = 7 TeV with the ATLAS detector

The production of a W boson in association with a single charm quark is studied using 4.6 fb−1 of pp collision data at s√ = 7 TeV collected with the ATLAS detector at the Large Hadron Collider. In events in which a W boson decays to an electron or muon, the charm quark is tagged either by its semileptonic decay to a muon or by the presence of a charmed meson. The integrated and differential cross sections as a function of the pseudorapidity of the lepton from the W-boson decay are measured. Results are compared to the predictions of next-to-leading-order QCD calculations obtained from various parton distribution function parameterisations. The ratio of the strange-to-down sea-quark distributions is determined to be 0.96+0.26−0.30 at Q 2 = 1.9 GeV2, which supports the hypothesis of an SU(3)-symmetric composition of the light-quark sea. Additionally, the cross-section ratio σ(W + +c¯¯)/σ(W − + c) is compared to the predictions obtained using parton distribution function parameterisations with different assumptions about the s−s¯¯¯ quark asymmetry

Viewpoint: How the Graphene Could Help to Decrease SARS-CoV-2 Spread?

The COVID-19 (Coronavirus Disease 2019), caused by the SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) began in December 2019 in Wuhan, China. Until February 2021, there are 110 million of infected people, 60 million have recovered and approximately 2.5 million have passed away worldwide according to WHO. The coronavirus pandemic is evolving very rapidly and represents a risk for health care workers and society in general. Moreover, pandemic has tested the limits of health systems by raising questions about forms of prevention, management of infections with conventional therapies and the use of diagnostic tools. In this article we discussed the possible role of the nanostructured-graphene based materials as aid tools for preventing the spread and infection of SARS-CoV-2. In this regard, nanotechnology could take part in the fight against the spread of future diseases caused by deadly viruses. However, its use should be well founded in terms of biocompatibility. Therefore, we have proposed an approach based on graphene nanomaterials as possible allies for the fight against the COVID-19 spread based on the physicochemical features that present these novel nanomaterials

Caracterización del movimiento fuerte en el emplazamiento de la presa de Itoiz

Se presenta en este trabajo una nueva caracterización del movimiento del suelo en la presa de Itoiz, consistente con la peligrosidad sísmica del emplazamiento. En primer lugar, proponemos una metodología con tres niveles de aproximación al movimiento esperado, que es después aplicada considerando las características particulares de la presa y su emplazamiento. Los cálculos de peligrosidad se realizan siguiendo la línea metodológica conocida como PSHA, con un método probabilista zonificado y formulando un árbol lógico que combina diferentes zonificaciones sísmicas y modelos de movimiento fuerte. La peligrosidad se representa en términos de la aceleración pico PGA y de las aceleraciones espectrales para periodos coincidentes con los de vibración de la presa, considerando dos estados de la misma correspondientes a presa vacía (T=0.1s) y presa con capacidad máxima de llenado (T=0.22 s). Se caracterizan los correspondientes movimientos para dos periodos de retorno, 975 años y 4975 años, asociados al sismo de proyecto y al sismo extremo, respectivamente. El efecto de sitio en el emplazamiento de la presa también fue tenido en cuenta. La metodología propuesta conduce a caracterizar el movimiento con tres niveles de detalle. En una primera etapa se obtienen los espectros de respuesta uniforme (UHS) para los dos niveles de movimiento referidos. Seguidamente se desarrolla un análisis de desagregación para obtener los sismos de control que previsiblemente pueden afectar mas a la presa. Estos se identifican como los que más contribuyen a los movimientos objeto dados por las aceleraciones espectrales de los dos periodos característicos, SA (0,1 s) y SA (0.22 s) y para los dos periodos de retorno de 975 y 4975 años asociados a lo sismos de proyecto y extremo. De ahí se obtienen los espectros de respuesta específicos para las cuatro combinaciones resultantes. Finalmente, se realiza una simulación del movimiento en el dominio del tiempo, obteniendo acelerogramas sintéticos mediante el método de número de onda discreto. Las simulaciones se realizaron considerando fuentes finitas en diferentes posiciones y evaluando el efecto de la directividad en las posibles fuentes consideradas. Se concluye destacando la importancia del efecto de directividad, en la caracterización del emplazamiento de la presa