University of Colorado Boulder

About: University of Colorado Boulder is a education organization based out in Boulder, Colorado, United States. It is known for research contribution in the topics: Population & Galaxy. The organization has 48794 authors who have published 115151 publications receiving 5387328 citations. The organization is also known as: CU Boulder & UCB.

Global patterns in belowground communities.

Abstract: Although belowground ecosystems have been studied extensively and soil biota play integral roles in biogeochemical processes, surprisingly we have a limited understanding of global patterns in belowground biomass and community structure. To address this critical gap, we conducted a meta-analysis of published data (> 1300 datapoints) to compare belowground plant, microbial and faunal biomass across seven of the major biomes on Earth. We also assembled data to assess biome-level patterns in belowground microbial community composition. Our analysis suggests that variation in microbial biomass is predictable across biomes, with microbial biomass carbon representing 0.6-1.1% of soil organic carbon (r(2) = 0.91) and 1-20% of total plant biomass carbon (r(2) = 0.42). Approximately 50% of total animal biomass can be found belowground and soil faunal biomass represents < 4% of microbial biomass across all biomes. The structure of belowground microbial communities is also predictable: bacterial community composition and fungal : bacterial gene ratios can be predicted reasonably well from soil pH and soil C : N ratios respectively. Together these results identify robust patterns in the structure of belowground microbial and faunal communities at broad scales which may be explained by universal mechanisms that regulate belowground biota across biomes.

Nivolumab plus ipilimumab or nivolumab alone versus ipilimumab alone in advanced melanoma (CheckMate 067): 4-year outcomes of a multicentre, randomised, phase 3 trial.

Abstract: Summary Background Previously reported results from the phase 3 CheckMate 067 trial showed a significant improvement in objective responses, progression-free survival, and overall survival with nivolumab plus ipilimumab or nivolumab alone compared with ipilimumab alone in patients with advanced melanoma. The aim of this report is to provide 4-year updated efficacy and safety data from this study. Methods In this phase 3 trial, eligible patients were aged 18 years or older with previously untreated, unresectable, stage III or stage IV melanoma, known BRAFV600 mutation status, and an Eastern Cooperative Oncology Group performance status of 0 or 1. Patients were randomly assigned 1:1:1 to receive intravenous nivolumab 1 mg/kg plus ipilimumab 3 mg/kg every 3 weeks for four doses, followed by nivolumab 3 mg/kg every 2 weeks, or nivolumab 3 mg/kg every 2 weeks plus placebo, or ipilimumab 3 mg/kg every 3 weeks for four doses plus placebo. Randomisation was done via an interactive voice response system with a permuted block schedule (block size of six) and stratification by PD-L1 status, BRAF mutation status, and metastasis stage. The patients, investigators, study site staff, and study funder were masked to the study drug administered. The co-primary endpoints were progression-free survival and overall survival. Efficacy analyses were done on the intention-to-treat population, whereas safety was assessed in all patients who received at least one dose of study drug. The results presented in this report reflect the 4-year update of the ongoing study with a database lock date of May 10, 2018. This study is registered with ClinicalTrials.gov, number NCT01844505. Findings Between July 3, 2013, and March 31, 2014, 945 patients were enrolled and randomly assigned to nivolumab plus ipilimumab (n=314), nivolumab (n=316), or ipilimumab (n=315). Median follow-up was 46·9 months (IQR 10·9–51·8) in the nivolumab plus ipilimumab group, 36·0 months (10·5–51·4) in the nivolumab group, and 18·6 months (7·6–49·5) in the ipilimumab group. At a minimum follow-up of 48 months from the date that the final patient was enrolled and randomised, median overall survival was not reached (95% CI 38·2–not reached) in the nivolumab plus ipilimumab group, 36·9 months (28·3–not reached) in the nivolumab group, and 19·9 months (16·9–24·6) in the ipilimumab group. The hazard ratio for death for the combination versus ipilimumab was 0·54 (95% CI 0·44–0·67; p Interpretation The results of this analysis at 4 years of follow-up show that a durable, sustained survival benefit can be achieved with first-line nivolumab plus ipilimumab or nivolumab alone in patients with advanced melanoma. Funding Bristol-Myers Squibb.

El Niño/Southern Oscillation behaviour since 1871 as diagnosed in an extended multivariate ENSO index (MEI.ext)

Abstract: El Nino/Southern Oscillation (ENSO) remains the most important coupled ocean–atmosphere phenomenon to cause global climate variability on seasonal to interannual time scales. This paper addresses the need for a reliable ENSO index that allows for the historical definition of ENSO events in the instrumental record back to 1871. The Multivariate ENSO Index (MEI) was originally defined as the first seasonally varying principal component of six atmosphere–ocean (COADS) variable fields in the tropical Pacific basin. It provides for a more complete and flexible description of the ENSO phenomenon than single variable ENSO indices such as the SOI or Nino 3.4 SST. Here we describe our effort to boil the MEI concept down to its most essential components (based on SLP, SST) to enable historical analyses that more than double its period of record to 1871–2005. The new MEI.ext confirms that ENSO activity went through a lull in the early- to mid-20th century, but was just about as prevalent one century ago as in recent decades. We diagnose strong relationships between peak amplitudes of ENSO events and their duration, as well as between their peak amplitudes and their spacing (periodicity). Our effort is designed to help with the assessment of ENSO conditions through as long a record as possible to be able to differentiate between ‘natural’ ENSO behaviour in all its rich facets, and the ‘Brave New World’ of this phenomenon under evolving GHG-related climate conditions. So far, none of the behaviour of recent ENSO events appears unprecedented, including duration, onset timing, and spacing in the last few decades compared to a full century before then. Copyright © 2011 Royal Meteorological Society

Role of the subducted slab, mantle wedge and continental crust in the generation of adakites from the Andean Austral Volcanic Zone

Abstract: All six Holocene volcanic centers of the Andean Austral Volcanic Zone (AVZ; 49–54°S) have erupted exclusively adakitic andesites and dacites characterized by low Yb and Y concentrations and high Sr/Y ratios, suggesting a source with residual garnet, amphibole and pyroxene, but little or no olivine and plagioclase. Melting of mafic lower crust may be the source for adakites in some arcs, but such a source is inconsistent with the high Mg# of AVZ adakites. Also, the AVZ occurs in a region of relatively thin crust ( 1), followed by limited interaction of this melt with the overlying mantle (≥90% MORB melt, ≤10% mantle), but only very little (≤1%) or no participation of either subducted sediment or crust. In contrast, models for the magmatic evolution of Burney (52°S), Reclus (51°S) and northernmost AVZ (49–50°S) andesites and dacites require melting of a mixture of MORB and subducted sediment, followed by interaction of this melt not only with the overlying mantle, but the crust as well. Crustal assimilation and fractional crystallization (AFC) processes and the mass contribution from the crust become more significant northwards in the AVZ as the angle of convergence becomes more orthogonal.

Software processes are software too

Abstract: The major theme of this meeting is the exploration of the importance of process as a vehicle for improving both the quality of software products and the way in which we develop and evolve them. In beginning this exploration it seems important to spend at least a short time examining the nature of process and convincing ourselves that this is indeed a promising vehicle.