Early Deglaciation in the Tropical Andes

Analysis of sediment records from lakes located beyond the glacial limit in the Andes has provided, for the first time, an independent assessment of effective moisture ( precipitation minus evaporation) and the timing of the last glaciation (1). Conditions were wet at the LGM and remained so until approximately 15,000 cal yr B.P. (2). However, deglaciation was under way from the LGM between 22,000 and 19,500 cal yr B.P., which reinforces the observation that deglaciation in the tropical Andes was primarily forced by an increase in mean annual temperature during a wet postglacial interval (3, 4)

Early Deglaciation in the Tropical Andes

Analysis of sediment records from lakes located beyond the glacial limit in the Andes has provided, for the first time, an independent assessment of effective moisture ( precipitation minus evaporation) and the timing of the last glaciation (1). Conditions were wet at the LGM and remained so until approximately 15,000 cal yr B.P. (2). However, deglaciation was under way from the LGM between 22,000 and 19,500 cal yr B.P., which reinforces the observation that deglaciation in the tropical Andes was primarily forced by an increase in mean annual temperature during a wet postglacial interval (3, 4)

Diversidad y riqueza herpetofaunística asociada al bosque de manejo forestal y áreas de cultivo, en Ixtlán de Juárez, Oaxaca; Herpetofaunistic diversity and richness in forest management and plantation areas in Ixtlán de Juárez, Oaxaca

Los bosques templados de Ixtlán de Juárez, Oaxaca, han estado sujetos a manejo forestal por más de 50 años; el efecto que dicha modificación tiene en los grupos de anfibios y reptiles necesita ser evaluado. El objetivo de este estudio fue analizar la abundancia, distribución y riqueza de especies de anfibios y reptiles en zonas agrícolas, y en áreas de bosque con manejo forestal (BMF). El BMF presenta franjas alteradas (FA), en la cual se ha removido la cobertura vegetal, y franjas conservadas (FC), donde predomina la vegetación de pino-encino. De acuerdo a nuestras estimaciones fue posible registrar el 76% de las especies presentes. En todo el estudio identificamos 37 especies, agrupadas en 25 géneros y 11 familias, lo que representa el 8.37% de las especies presentes en Oaxaca. En el BMF identificamos 15 especies, de las cuales 13 son reptiles y dos son anfibios. La FA tuvo nueve especies, mientras que en la FC registramos ocho especies. En las AM registramos 31 especies, agrupadas en 22 géneros y 10 familias. Las zonas con mayor diversidad fueron las AM y las FA en comparación con las FC en donde la diversidad de especies fue menor. A pesar de que las FC y FA son colindantes la similitud fue mayor entre las AM, las cuales tienen más de 50 años de haber sido perturbadas, y las FA, las cuales han sido recientemente modificadas. Las prácticas de manejo forestal que caracterizan a Ixtlán de Juárez han promovido la interconectividad entre las zonas evitando, en cierta medida, una modificación en el ensamble natural de la herpetofauna. Se recomienda continuar con el monitoreo espacial y temporal de la herpetofauna no solamente en áreas naturales, sino también en las áreas de manejo forestal y modificadas que no han perdido conectividad con las zonas conservadas o de manejo forestal.Los bosques templados de Ixtlán de Juárez, Oaxaca, han estado sujetos a manejo forestal por más de 50 años; el efecto que dicha modificación tiene en los grupos de anfibios y reptiles necesita ser evaluado. El objetivo de este estudio fue analizar la abundancia, distribución y riqueza de especies de anfibios y reptiles en zonas agrícolas, y en áreas de bosque con manejo forestal (BMF). El BMF presenta franjas alteradas (FA), en la cual se ha removido la cobertura vegetal, y franjas conservadas (FC), donde predomina la vegetación de pino-encino. De acuerdo a nuestras estimaciones fue posible registrar el 76% de las especies presentes. En todo el estudio identificamos 37 especies, agrupadas en 25 géneros y 11 familias, lo que representa el 8.37% de las especies presentes en Oaxaca. En el BMF identificamos 15 especies, de las cuales 13 son reptiles y dos son anfibios. La FA tuvo nueve especies, mientras que en la FC registramos ocho especies. En las AM registramos 31 especies, agrupadas en 22 géneros y 10 familias. Las zonas con mayor diversidad fueron las AM y las FA en comparación con las FC en donde la diversidad de especies fue menor. A pesar de que las FC y FA son colindantes la similitud fue mayor entre las AM, las cuales tienen más de 50 años de haber sido perturbadas, y las FA, las cuales han sido recientemente modificadas. Las prácticas de manejo forestal que caracterizan a Ixtlán de Juárez han promovido la interconectividad entre las zonas evitando, en cierta medida, una modificación en el ensamble natural de la herpetofauna. Se recomienda continuar con el monitoreo espacial y temporal de la herpetofauna no solamente en áreas naturales, sino también en las áreas de manejo forestal y modificadas que no han perdido conectividad con las zonas conservadas o de manejo forestal

Techniques for one-loop calculations in constrained differential renormalization

We describe in detail the constrained procedure of differential renormalization and develop the techniques required for one-loop calculations. As an illustration we renormalize Scalar QED and show that the two-, three- and four-point Ward identities are automatically satisfied.Comment: LaTex, 29 pages with 4 Postscript figure

Regeneración de oreomunnea mexicana (Juglandaceae), una especie relicto, amenazada del bosque de niebla de sierra juárez, oaxaca, México

Oreomunnea mexicana (Stand.) J.F. Leroy is a relict species, threatened and a key species for cloud ecosystem functionof the Sierra Juárez, Oaxaca, the most extensive and best conserved in Mexico. This study includes a diagnostic on two critical stages of the process of population regeneration of O. mexicana. To this end, it analyzed the: 1) production, dispersion, viability and germination of seeds, 2) effect of predation on the growth and survival of the seedlings, and 3) effect of environmental variables (soil, canopy structure and solar radiation) on the regeneration of the species. The study was made from 2014 to 2015 in the cloud forest of Santiago Comaltepec, Oaxaca, Mexico, in two locations (San Bernardo and El Orquidiario). Differences in seed production were found between years and between locations, as well as low seed viability and a high percentage of seed parasitism. The establishment and growth of the seedlings are subject to find suitable microhabitats, since seedlings have specific illumination and soil requirements. The high edaphic specificity faced by the species could be a key factor for its fragmented and discontinuous distribution in Sierra Juárez. Further population regeneration studies are recommended to increase knowledge of the species and thereby achieve its conservation. © 2019, Instituto de Ecologia, A.C. All rights reserved

Reductions in External Divalent Cations Evoke Novel Voltage-Gated Currents in Sensory Neurons

It has long been recognized that divalent cations modulate cell excitability. Sensory nerve excitability is of critical importance to peripheral diseases associated with pain, sensory dysfunction and evoked reflexes. Thus we have studied the role these cations play on dissociated sensory nerve activity. Withdrawal of both Mg2+ and Ca2+ from external solutions activates over 90% of dissociated mouse sensory neurons. Imaging studies demonstrate a Na+ influx that then causes depolarization-mediated activation of voltage-gated Ca2+ channels (CaV), which allows Ca2+ influx upon divalent re-introduction. Inhibition of CaV (ω-conotoxin, nifedipine) or NaV (tetrodotoxin, lidocaine) fails to reduce the Na+ influx. The Ca2+ influx is inhibited by CaV inhibitors but not by TRPM7 inhibition (spermine) or store-operated channel inhibition (SKF96365). Withdrawal of either Mg2+ or Ca2+ alone fails to evoke cation influxes in vagal sensory neurons. In electrophysiological studies of dissociated mouse vagal sensory neurons, withdrawal of both Mg2+ and Ca2+ from external solutions evokes a large slowly-inactivating voltage-gated current (IDF) that cannot be accounted for by an increased negative surface potential. Withdrawal of Ca2+ alone fails to evoke IDF. Evidence suggests IDF is a non-selective cation current. The IDF is not reduced by inhibition of NaV (lidocaine, riluzole), CaV (cilnidipine, nifedipine), KV (tetraethylammonium, 4-aminopyridine) or TRPM7 channels (spermine). In summary, sensory neurons express a novel voltage-gated cation channel that is inhibited by external Ca2+ (IC50∼0.5 µM) or Mg2+ (IC50∼3 µM). Activation of this putative channel evokes substantial cation fluxes in sensory neurons

Modern microwave methods in solid state inorganic materials chemistry: from fundamentals to manufacturing

No abstract available

Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

This paper presents measurements of the $W^+ \rightarrow \mu^+\nu$ and $W^- \rightarrow \mu^-\nu$ cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector

A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13  TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139  fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV