Natural history and evolution of an elevational generalist, the Cinereous Conebill (Conirostrum cinereum)

Elevational generalism is relatively rare in the tropical Andes Mountains, likely owing to the inherent requirements of enduring a high degree of climatic zonation and coping with hypoxic stress. The Cinereous Conebill (Conirostrum cinereum) appears to be an exception, and inhabits a continuous elevational distribution that spans over 4,500 m. Two subspecies, cinereum and fraseri, are restricted to high elevations and may be isolated, whereas the third and most widespread, littorale, occurs continuously along the western slope of the Andes from 0 to over 4,500 m. First, we aim to characterize the morphology, genetics, and climatic niche of the three subspecies using a comparative biogeographic approach to explore patterns and timing of differentiation and to consider possible mechanisms of diversification. Second, we study whether hemoglobin adaptation plays a role in this elevational generalist’s ability to thrive in high-elevation environments, and whether localized adaptation is possible despite altitudinal migration and gene flow. We used a comparative phylogeographic framework to examine whether lineage divergence within C. cinereum is associated with climatic, geographic, and/or physiological barriers leading to incipient speciation

Ecological divergence of a mesocosm in an eastern boundary upwelling system assessed with multi-marker environmental DNA metabarcoding

Eastern boundary upwelling systems (EBUS) contribute a disproportionate fraction of the global fish catch relative to their size and are especially susceptible to global environmental change. Here we present the evolution of communities over 50 days in an in situ mesocosm 6 km offshore of Callao, Peru and in the nearby unenclosed coastal Pacific Ocean. The communities were monitored using multi-marker environmental DNA (eDNA) metabarcoding and flow cytometry. DNA extracted from weekly water samples were subjected to amplicon sequencing for four genetic loci: 1) the V1-V2 region of the 16S rRNA gene, for photosynthetic eukaryotes (via their chloroplasts) and bacteria; 2) the V9 region of the 18S rRNA gene for exploration of eukaryotes but targeting phytoplankton; 3) cytochrome oxidase I (COI), for exploration of eukaryotic taxa but targeting invertebrates, and 4) the 12S rRNA gene, targeting vertebrates. The multi-marker approach showed a divergence of communities (from microbes to fish) between the mesocosm and the unenclosed ocean. Together with the environmental information, the genetic data furthered our mechanistic understanding of the processes that are shaping EBUS communities in a changing ocean. The unenclosed ocean experienced significant variability over the course of the 50-day experiment with temporal shifts in community composition but remained dominated by organisms that are characteristic of high nutrient, upwelling conditions (e.g. diatoms, copepods, anchovies). A large directional change was found in the mesocosm community. The mesocosm community that developed was characteristic of upwelling regions when upwelling relaxes and waters stratify (e.g. dinoflagellates, nanoflagellates). The selection of dinoflagellates under the warm (coastal El Ni&ntilde;o) and stratified conditions in the mesocosm may be an indication of how EBUS will respond under the global environmental changes (i.e. continued global warming) forecast by the IPCC.</p

Contribution of a mutational hot spot to hemoglobin adaptation in high-altitude Andean house wrens

A key question in evolutionary genetics is why certain mutations or certain types of mutation make disproportionate contributions to adaptive phenotypic evolution. In principle, the preferential fixation of particular mutations could stem directly from variation in the underlying rate of mutation to function-altering alleles. However, the influence of mutation bias on the genetic architecture of phenotypic evolution is difficult to evaluate because data on rates of mutation to function-altering alleles are seldom available. Here, we report the discovery that a single point mutation at a highly mutable site in the βA-globin gene has contributed to an evolutionary change in hemoglobin (Hb) function in high-altitude Andean house wrens (Troglodytes aedon). Results of experiments on native Hb variants and engineered, recombinant Hb mutants demonstrate that a nonsynonymous mutation at a CpG dinucleotide in the βA-globin gene is responsible for an evolved difference in Hb–O2 affinity between high- and low-altitude house wren populations. Moreover, patterns of genomic differentiation between high- and low-altitude populations suggest that altitudinal differentiation in allele frequencies at the causal amino acid polymorphism reflects a history of spatially varying selection. The experimental results highlight the influence of mutation rate on the genetic basis of phenotypic evolution by demonstrating that a large-effect allele at a highly mutable CpG site has promoted physiological differentiation in blood O2 transport capacity between house wren populations that are native to different elevations

Global perspectives on observing ocean boundary current systems

Ocean boundary current systems are key components of the climate system, are home to highly productive ecosystems, and have numerous societal impacts. Establishment of a global network of boundary current observing systems is a critical part of ongoing development of the Global Ocean Observing System. The characteristics of boundary current systems are reviewed, focusing on scientific and societal motivations for sustained observing. Techniques currently used to observe boundary current systems are reviewed, followed by a census of the current state of boundary current observing systems globally. The next steps in the development of boundary current observing systems are considered, leading to several specific recommendations.Fil: Todd, Robert E.. Woods Hole Oceanographic Institution; Estados UnidosFil: Chavez, Francisco. Monterey Bay Aquarium Research Institute; Estados UnidosFil: Clayton, Sophie. Old Dominion University; Estados UnidosFil: Cravatte, Sophie E.. Centre National de la Recherche Scientifique. Institut de Recherche pour le Développement; Francia. Universite de Toulouse; FranciaFil: Goes, Marlos P.. University of Miami; Estados UnidosFil: Graco, Michelle I.. Instituto del Mar del Peru; PerúFil: Lin, Xiaopei. Ocean University of China; ChinaFil: Sprintall, Janet. University of California; Estados UnidosFil: Zilberman, Nathalie V.. University of California; Estados UnidosFil: Archer, Matthew. California Institute of Technology; Estados UnidosFil: Arístegui, Javier. Universidad de Las Palmas de Gran Canaria; EspañaFil: Balmaseda, Magdalena A.. European Centre for Medium-Range Weather Forecasts; Reino UnidoFil: Bane, John M.. University of North Carolina; Estados UnidosFil: Baringer, Molly O.. Atlantic Oceanographic and Meteorological Laboratory ; Estados UnidosFil: Barth, John A.. State University of Oregon; Estados UnidosFil: Beal, Lisa M.. University of Miami; Estados UnidosFil: Brandt, Peter. Geomar-Helmholtz Centre for Ocean Research Kiel; AlemaniaFil: Calil, Paulo H.. Universidade Federal do Rio Grande; BrasilFil: Campos, Edmo. Universidade de Sao Paulo; BrasilFil: Centurioni, Luca R.. University of California; Estados UnidosFil: Chidichimo, María Paz. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval; ArgentinaFil: Cirano, Mauro. Universidade Federal do Rio de Janeiro; BrasilFil: Cronin, Meghan F.. National Oceanic and Atmospheric Administration. Pacific Marine Environmental Laboratory; Estados UnidosFil: Curchitser, Enrique N.. Rutgers University; Estados UnidosFil: Davis, Russ E.. University of California; Estados UnidosFil: Dengler, Marcus. Geomar-Helmholtz Centre for Ocean Research Kiel; AlemaniaFil: DeYoung, Brad. Memorial University of Newfoundland; CanadáFil: Dong, Shenfu. University of Miami; Estados UnidosFil: Escribano, Ruben. Universidad de Concepción; ChileFil: Fassbender, Andrea J.. Monterey Bay Aquarium Research Institute; Estados Unido

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO

Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file

Hemoxygenase-1 Promotes Head and Neck Cancer Cell Viability

Head and neck squamous cell carcinoma (HNSCC) is a remarkably heterogeneous disease with around 50% mortality, a fact that has prompted researchers to try new approaches to improve patient survival. Hemoxygenase-1 (HO-1) is the rate-limiting step for heme degradation into carbon monoxide, free iron and biliverdin. We have previously reported that HO-1 protein is upregulated in human HNSCC samples and that it is localized in the cytoplasmic and nuclear compartments; additionally, we have demonstrated that HO-1 nuclear localization is associated with malignant progression. In this work, by using pharmacological and genetic experimental approaches, we begin to elucidate the mechanisms through which HO-1 plays a role in HNSCC. We found that high HO-1 mRNA was associated with decreased patient survival in early stages of HNSCC. In vitro experiments have shown that full-length HO-1 localizes in the cytoplasm, and that, depending on its enzymatic activity, it increases cell viability and promotes cell cycle progression. Instead, HO-1 does not alter migration capacity. Furthermore, we show that C-terminal truncated HO-1 localizes into the nucleus, increases cell viability and promotes cell cycle progression. In conclusion, we herein demonstrate that HO-1 displays protumor activities in HNSCC that depend, at least in part, on the nuclear localization of HO-1.Centro de Investigaciones Inmunológicas Básicas y Aplicada

Utilization of mechanical power and associations with clinical outcomes in brain injured patients. a secondary analysis of the extubation strategies in neuro-intensive care unit patients and associations with outcome (ENIO) trial

BackgroundThere is insufficient evidence to guide ventilatory targets in acute brain injury (ABI). Recent studies have shown associations between mechanical power (MP) and mortality in critical care populations. We aimed to describe MP in ventilated patients with ABI, and evaluate associations between MP and clinical outcomes.MethodsIn this preplanned, secondary analysis of a prospective, multi-center, observational cohort study (ENIO, NCT03400904), we included adult patients with ABI (Glasgow Coma Scale &lt;= 12 before intubation) who required mechanical ventilation (MV) &gt;= 24 h. Using multivariable log binomial regressions, we separately assessed associations between MP on hospital day (HD)1, HD3, HD7 and clinical outcomes: hospital mortality, need for reintubation, tracheostomy placement, and development of acute respiratory distress syndrome (ARDS).ResultsWe included 1217 patients (mean age 51.2 years [SD 18.1], 66% male, mean body mass index [BMI] 26.3 [SD 5.18]) hospitalized at 62 intensive care units in 18 countries. Hospital mortality was 11% (n = 139), 44% (n = 536) were extubated by HD7 of which 20% (107/536) required reintubation, 28% (n = 340) underwent tracheostomy placement, and 9% (n = 114) developed ARDS. The median MP on HD1, HD3, and HD7 was 11.9 J/min [IQR 9.2-15.1], 13 J/min [IQR 10-17], and 14 J/min [IQR 11-20], respectively. MP was overall higher in patients with ARDS, especially those with higher ARDS severity. After controlling for same-day pressure of arterial oxygen/fraction of inspired oxygen (P/F ratio), BMI, and neurological severity, MP at HD1, HD3, and HD7 was independently associated with hospital mortality, reintubation and tracheostomy placement. The adjusted relative risk (aRR) was greater at higher MP, and strongest for: mortality on HD1 (compared to the HD1 median MP 11.9 J/min, aRR at 17 J/min was 1.22, 95% CI 1.14-1.30) and HD3 (1.38, 95% CI 1.23-1.53), reintubation on HD1 (1.64; 95% CI 1.57-1.72), and tracheostomy on HD7 (1.53; 95%CI 1.18-1.99). MP was associated with the development of moderate-severe ARDS on HD1 (2.07; 95% CI 1.56-2.78) and HD3 (1.76; 95% CI 1.41-2.22).ConclusionsExposure to high MP during the first week of MV is associated with poor clinical outcomes in ABI, independent of P/F ratio and neurological severity. Potential benefits of optimizing ventilator settings to limit MP warrant further investigation