2,816 research outputs found
A comparison of the Caulobacter NA1000 and K31 genomes reveals extensive genome rearrangements and differences in metabolic potential
The genus Caulobacter is found in a variety of habitats and is known for its abilityto thrive in low-nutrient conditions. K31 is a novel Caulobacter isolate that has the ability to tolerate copper and chlorophenols, and can grow at 48Cwith a doubling time of 40 h. K31 contains a 5.5 Mb chromosome that codes for more than 5500 proteins and two large plasmids (234 and 178 kb) thatcode for 438 additional proteins. A comparison of the K31 and the Caulobactercrescentus NA1000 genomes revealed extensive rearrangements of gene order,suggesting that the genomes had been randomly scrambled. However, a careful analysis revealed that the distance from the origin of replication was conserved for the majority of the genes and that many of the rearrangements involved inversions that included the origin of replication. On a finer scale, numerous small indels were observed. K31 proteins involved in essential functions shared 80-95% amino acid sequence identity with their C. crescentus homologues,while other homologue pairs tended to have lower levels of identity.In addition, the K31 chromosome contains more than 1600 genes with nohomologue in NA1000
Testbeam studies of pre-prototype silicon strip sensors for the LHCb UT upgrade project
The LHCb experiment is preparing for a major upgrade in 2018-2019. One of the
key components in the upgrade is a new silicon tracker situated upstream of the
analysis magnet of the experiment. The Upstream Tracker (UT) will consist of
four planes of silicon strip detectors, with each plane covering an area of
about 2 m. An important consideration of these detectors is their
performance after they have been exposed to a large radiation dose. In this
article we present test beam results of pre-prototype n-in-p and p-in-n sensors
that have been irradiated with fluences up to
cm.Comment: 25 pages, 20 figure
Geographical origin of dabbling ducks wintering in Iberia: Sex differences and implications for pair formation
Los humedales ibéricos naturales y antropógenos del sur de Europa son bien conocidos por sustentar a un gran número de aves migratorias acuáticas del Palaearctico en cada invierno. Sin embargo, la información sobre el origen geográfico de los patos de humedal que pasan el invierno en estos espacios es escasa y se limita principalmente a datos de sonar. Aquí, hemos utilizado marcadores isotópicos para determinar el origen geográfico de machos y hembras de Pintails septentrional, Anas acuta y Anas crecca euroasiática en Extremadura, en el interior de la península Ibérica, sitio clave para invernar los patos de humedal. Además, hemos instalado seis etiquetas GPSGSM en Pintails septentrional para complementar los datos derivados del análisis de isótopos estables. La mayoría (> 70%) de los Pintails septentrional, dentro del primer año calendario, fueron asignados a regiones situadas por encima de los 55° N, volando 2600-5600 km desde sus regiones de procedencia a Extremadura. Los valores promedio de δ2Hf variaron significativamente entre macho y hembra de Pintails septentrional, sugiriendo que los sexos tienen diferentes orígenes geográficos. Los datos de los adultos etiquetados Pintails septentrional apoyan los datos isotópicos, un macho volando más de 5000 km de la costa de la mar Pechora (Rusia). La mayoría (> 70%) de los Teal euroasiáticos, dentro del primer año calendario, fueron asignados a la región situada entre 48° y 60° N y viajaron 1500-4500 km para llegar en Extremadura. Los machos y hembras de Cerceta euroasiáticos mostraron diferencias marginales en valores promedio de δ2Hf. En patos de humedal migratorios, el emparejamiento se produce normalmente en las zonas de invernada, y los patos en su primer invierno pueden reproducirse en la primavera siguiente. Para Pintails septentrional, la formación de parejas en Extremadura podría suceder entre individuos con diferentes orígenes geográficos, lo que podría contribuir a la variabilidad genética de su descendencia.Natural and anthropogenic Iberian wetlands in southern Europe are well known for supporting large numbers of migratory Palaearctic waterbirds each winter. However, information on the geographical origin of dabbling ducks overwintering in these wetlands is scarce and mostly limited to data from ringing recoveries. Here, we used intrinsic isotopic markers to determine the geographical origin of male and female Northern Pintails Anas acuta and Eurasian Teal Anas crecca in Extremadura, inland Iberia, a key site for overwintering dabbling ducks. Additionally, we fitted six Northern Pintails with GPSGSM tags to complement the data derived from stable isotope analysis. Most (> 70%) first calendar-year Northern Pintails were assigned to regions above 55°N, flying 2600–5600 km from their main natal regions to Extremadura. Mean values of δ2Hf varied significantly between male and female Northern Pintails, suggesting that the sexes had different geographical origins. Data from tagged adult Northern Pintails supported the isotopic data, one male flying more than 5000 km to the coast of the Pechora Sea (Russia). Most (> 70%) first calendar-year Eurasian Teal were assigned to the region between 48° and 60°N, travelling 1500–4500 km to arrive in Extremadura. Male and female Eurasian Teal showed marginal differences in mean values of δ2Hf. In migratory dabbling ducks, pairing typically occurs on the wintering grounds, and ducks in their first winter can breed the following spring. For Northern Pintails, pair formation in Extremadura could occur between individuals with different geographical origins, which could contribute to the genetic variability of their offspring.Trabajo patrocinado por:
Junta de Extremadura. Proyecto PRI 09C128
Gobierno de Extremadura y Fondos FEDER. Ayuda GR10174
Confederación Hidrográfica del Guadiana (Ministerio de Medio Ambiente). Ayuda financierapeerReviewe
Priority sites for wildfowl conservation in Mexico
A set of priority sites for wildfowl conservation in Mexico was determined using contemporary count data (1991–2000) from the U.S. Fish & Wildlife Service mid-winter surveys. We used a complementarity approach implemented through linear integer programming that addresses particular conservation concerns for every species included in the analysis and large fluctuations in numbers through time.
A set of 31 priority sites was identified, which held more than 69% of the mid-winter count total in Mexico during all surveyed years. Six sites were in the northern highlands, 12 in the central highlands, six on the Gulf of Mexico coast and seven on the upper Pacific coast. Twenty-two sites from the priority set have previously been identified as qualifying for designation as wetlands of international importance under the Ramsar Convention and 20 sites are classified as Important Areas for Bird Conservation in Mexico. The information presented here provides an accountable, spatially-explicit, numerical basis for ongoing conservation planning efforts in Mexico, which can be used to improve existing wildfowl conservation networks in the country and can also be useful for conservation planning exercises elsewhere
The evolution of the cosmic molecular gas density
One of the last missing pieces in the puzzle of galaxy formation and
evolution through cosmic history is a detailed picture of the role of the cold
gas supply in the star-formation process. Cold gas is the fuel for star
formation, and thus regulates the buildup of stellar mass, both through the
amount of material present through a galaxy's gas mass fraction, and through
the efficiency at which it is converted to stars. Over the last decade,
important progress has been made in understanding the relative importance of
these two factors along with the role of feedback, and the first measurements
of the volume density of cold gas out to redshift 4, (the "cold gas history of
the Universe") has been obtained. To match the precision of measurements of the
star formation and black-hole accretion histories over the coming decades, a
two orders of magnitude improvement in molecular line survey speeds is required
compared to what is possible with current facilities. Possible pathways towards
such large gains include significant upgrades to current facilities like ALMA
by 2030 (and beyond), and eventually the construction of a new generation of
radio-to-millimeter wavelength facilities, such as the next generation Very
Large Array (ngVLA) concept.Comment: 7 pages, 2 figures, Science White paper submitted to Astro2020
Decadal Surve
Tendon overload results in alterations in cell shape and increased markers of inflammation and matrix degradation
Tendon injury is thought to involve both damage accumulation within the matrix and an accompanying cell response. While several studies have characterized cell and matrix response in chronically injured tendons, few have assessed the initial response of tendon to overload-induced damage. In this study, we assessed cell response to cyclic loading. Fascicle bundles from the equine superficial digital flexor tendon were exposed to cyclic loading in vitro, designed to mimic a bout of high-intensity exercise. Changes in cell morphology and protein-level alterations in markers of matrix inflammation and degradation were investigated. Loading resulted in matrix damage, which was accompanied by cells becoming rounder. The inflammatory markers cyclooxygenase-2 and interleukin-6 were increased in loaded samples, as were matrix metalloproteinase-13 and the collagen degradation marker C1,2C. These results indicate upregulation of inflammatory and degradative pathways in response to overload-induced in vitro, which may be initiated by alterations in cell strain environment because of localized matrix damage. This provides important information regarding the initiation of tendinopathy, suggesting that inflammation may play an important role in the initial cell response to tendon damage. Full understanding of the early tenocyte response to matrix damage is critical in order to develop effective treatments for tendinopathy
CMB-S4 Science Book, First Edition
This book lays out the scientific goals to be addressed by the
next-generation ground-based cosmic microwave background experiment, CMB-S4,
envisioned to consist of dedicated telescopes at the South Pole, the high
Chilean Atacama plateau and possibly a northern hemisphere site, all equipped
with new superconducting cameras. CMB-S4 will dramatically advance cosmological
studies by crossing critical thresholds in the search for the B-mode
polarization signature of primordial gravitational waves, in the determination
of the number and masses of the neutrinos, in the search for evidence of new
light relics, in constraining the nature of dark energy, and in testing general
relativity on large scales
Recommended from our members
Board gender quotas: Exploring ethical tensions from a multi-theoretical perspective
Despite 40 years of equal opportunities policies and more than two decades of government and organization initiatives aimed at helping women reach the upper echelons of the corporate world, women are seriously underrepresented on corporate boards. Recently, fifteen countries sought to redress this imbalance by introducing gender quotas for board representation. The introduction of board gender quota legislation creates ethical tensions and dilemmas which we categorize in terms of motivations, legitimacy, and outcomes. We investigate these tensions through four overarching theoretical perspectives: institutional, stakeholder, social identity, and social capital. We outline a future research agenda based on how these tensions offer greater focus to research on quotas and more broadly to ethics and diversity in organizations in terms of theory, anticipated ethical tensions, data, and methodology. In sum, our review seeks to synthesize existing multidisciplinary research and stimulate future enquiry on this expanding set of legislation
Measurement of the Associated Production Cross Section in Collisions at TeV
We present the first measurement of associated direct photon + muon
production in hadronic collisions, from a sample of 1.8 TeV
collisions recorded with the Collider Detector at Fermilab. Quantum
chromodynamics (QCD) predicts that these events are primarily from the Compton
scattering process , with the final state charm quark producing
a muon. Hence this measurement is sensitive to the charm quark content of the
proton. The measured cross section of is compared to a
leading-order QCD parton shower model as well as a next-to-leading-order QCD
calculation.Comment: 12 pages, 4 figures Added more detailed description of muon
background estimat
Inclusive search for same-sign dilepton signatures in pp collisions at root s=7 TeV with the ATLAS detector
An inclusive search is presented for new physics in events with two isolated leptons (e or mu) having the same electric charge. The data are selected from events collected from p p collisions at root s = 7 TeV by the ATLAS detector and correspond to an integrated luminosity of 34 pb(-1). The spectra in dilepton invariant mass, missing transverse momentum and jet multiplicity are presented and compared to Standard Model predictions. In this event sample, no evidence is found for contributions beyond those of the Standard Model. Limits are set on the cross-section in a fiducial region for new sources of same-sign high-mass dilepton events in the ee, e mu and mu mu channels. Four models predicting same-sign dilepton signals are constrained: two descriptions of Majorana neutrinos, a cascade topology similar to supersymmetry or universal extra dimensions, and fourth generation d-type quarks. Assuming a new physics scale of 1 TeV, Majorana neutrinos produced by an effective operator V with masses below 460 GeV are excluded at 95% confidence level. A lower limit of 290 GeV is set at 95% confidence level on the mass of fourth generation d-type quarks
- …
