Environment and the cosmic evolution of star formation

We present a mark correlation analysis of the galaxies in the Sloan Digital Sky Survey using weights provided by MOPED. The large size of the sample permits statistically significant statements about how galaxies with different metallicities and star formation histories are spatially correlated. Massive objects formed a larger fraction of their stars at higher redshifts and over shorter timescales than did less massive objects (sometimes called down-sizing). We find that those galaxies which dominated the cosmic star formation at z~3 are predominantly in clusters today, whereas galaxies which dominate the star formation at z~0 inhabit substantially lower mass objects in less dense regions today. Hence, our results indicate that star formation and chemical enrichment occured first in the denser regions of the Universe, and moved to less dense regions at later times.Comment: 4 pages, 4 figures, submitted to ApJ

Neighbourhood, Route and Workplace-Related Environmental Characteristics Predict Adults' Mode of Travel to Work

Commuting provides opportunities for regular physical activity which can reduce the risk of chronic disease. Commuters' mode of travel may be shaped by their environment, but understanding of which specific environmental characteristics are most important and might form targets for intervention is limited. This study investigated associations between mode choice and a range of objectively assessed environmental characteristics.Participants in the Commuting and Health in Cambridge study reported where they lived and worked, their usual mode of travel to work and a variety of socio-demographic characteristics. Using geographic information system (GIS) software, 30 exposure variables were produced capturing characteristics of areas around participants' homes and workplaces and their shortest modelled routes to work. Associations between usual mode of travel to work and personal and environmental characteristics were investigated using multinomial logistic regression.Of the 1124 respondents, 50% reported cycling or walking as their usual mode of travel to work. In adjusted analyses, home-work distance was strongly associated with mode choice, particularly for walking. Lower odds of walking or cycling rather than driving were associated with a less frequent bus service (highest versus lowest tertile: walking OR 0.61 [95% CI 0.20–1.85]; cycling OR 0.43 [95% CI 0.23–0.83]), low street connectivity (OR 0.22, [0.07–0.67]; OR 0.48 [0.26–0.90]) and free car parking at work (OR 0.24 [0.10–0.59]; OR 0.55 [0.32–0.95]). Participants were less likely to cycle if they had access to fewer destinations (leisure facilities, shops and schools) close to work (OR 0.36 [0.21–0.62]) and a railway station further from home (OR 0.53 [0.30–0.93]). Covariates strongly predicted travel mode (pseudo r-squared 0.74).Potentially modifiable environmental characteristics, including workplace car parking, street connectivity and access to public transport, are associated with travel mode choice, and could be addressed as part of transport policy and infrastructural interventions to promote active commuting

Document Classification

We present an overview of the document classification process and present research conducted against the newly constructed SBIR-STTR corpus. Specifically, the current methods in use for annotation, corpus construction, feature construction, feature weighting, and classifier algorithms are surveyed. We introduce a new dataset derived from public data downloaded from sbir.gov and the Text Annotation Toolkit (TAT) 1 for use in classification research. TAT is a collection of independent components packaged together into one open source software application. TAT was engineered to support the document classification process and workflow. Tracking of changes in a working corpus, saving data used in the training of classifiers to ensure reproducibility, and providing a mechanism for interacting with copyright protected corpora are all fundamental issues that TAT addresses. TAT is built using the robust Open IDE [35] framework that allows plug-in developers access to standard well tested libraries saving years of development time. The main goal of TAT is to minimize the labor intensive process of creating labelled data that can be used to train, test, and deploy machine learning models for automated text annotation. Additionally, TAT allows researchers an easy method to automatically reproduce prior results. The toolkit can facilitate the annotation of text using different machine learning packages as well as corpora with different metadata specifications. 1TAT is freely available for download from trac.boisestate.ed

A longitudinal study of the distance that young people walk to school.

Walking or cycling to school has been associated with important health benefits. Distance between home and school is the main correlate of active commuting to school, but how far children walk to school and how this changes as children age is unknown. Mode of commuting and objectively-assessed distance to school were measured at 3 time points: aged 9/10 years, 10/11 years and 13/14 years. Data were analysed using ROC-curve analyses. With age, children walked further to school; the threshold distance that best discriminated walkers from passive commuters was 1421 m in 10-year-olds, 1627 m in 11-year-olds and 3046 m in 14-year-olds. Future interventions should consider the distance that young people actually walk.The SPEEDY study is funded by the National Prevention Research Initiative (http://www.npri.org.uk), consisting of the following Funding Partners: British Heart Foundation; Cancer Research UK; Department of Health; Diabetes UK; Economic and Social Research Council; Medical Research Council; Health and Social Care Research and Development Office for the Northern Ireland; Chief Scientist Office, Scottish Government Health Directorates; Welsh Assembly Government and World Cancer Research Fund. This work was also supported by the Medical Research Council [Unit Programme numbers MC_UU_12015/7; MC_UU_12015/4] and the Centre for Diet and Activity Research (CEDAR), a UKCRC Public Health Research: Centre of Excellence. Funding from the British Heart Foundation, Economic and Social Research Council, Medical Research Council, the National Institute for Health Research, and the Wellcome Trust, under the auspices of the UK Clinical Research Collaboration, is gratefully acknowledged. Jenna Panter is funded through a post-doctoral fellowship funded by the National Institute of Health Research. The views and opinions expressed herein are those of the authors and do not necessarily reflect those of the NIHR PHR programme or the Department of Health.This is the final version. It was first published by Elsevier at http://www.sciencedirect.com/science/article/pii/S135382921400159

40Ar–39Ar dating of volcanogenic products from the AND-2A core (ANDRILL Southern McMurdo Sound Project, Antarctica): correlations with the Erebus Volcanic Province and implications for the age model of the core

The AND-2A drillcore (Antarctic Drilling Program—ANDRILL) was successfully completed in late 2007 on the Antarctic continental margin (Southern McMurdo Sound, Ross Sea) with the aim of tracking ice proximal to shallow marine environmental fluctuations and to document the 20-Ma evolution of the Erebus Volcanic Province. Lava clasts and tephra layers from the AND-2A drillcore were investigated from a petrographic and stratigraphic point of view and analyzed by the 40Ar–39Ar laser technique in order to constrain the age model of the core and to gain information on the style and nature of sediment deposition in the Victoria Land Basin since Early Miocene. Ten out of 17 samples yielded statistically robust 40Ar–39Ar ages, indicating that the AND-2A drillcore recovered ≤230 m of Middle Miocene (∼128–358 m below sea floor, ∼11.5–16.0 Ma) and >780 m of Early Miocene (∼358–1093 m below sea floor, ∼16.0–20.1 Ma). Results also highlight a nearly continuous stratigraphic record from at least 358 m below sea floor down hole, characterized by a mean sedimentation rate of ∼19 cm/ka, possible oscillations of no more than a few hundreds of ka and a break within ∼17.5–18.1 Ma. Comparison with available data from volcanic deposits on land, suggests that volcanic rocks within the AND-2A core were supplied from the south, possibly with source areas closer to the drill site for the upper core levels, and from 358 m below sea floor down hole, with the “proto-Mount Morning” as the main source

Early Miocene volcanic activity and paleoenvironment conditions recorded in tephra layers of the AND-2A core (southern McMurdo Sound, Antarctica)

The ANtarctic geological DRILLing program (ANDRILL) successfully recovered 1138.54 m of core from drillhole, AND-2A, in the Ross Sea sediments (Antarctica). The core is composed of terrigenous claystones, siltstones, sandstones, conglomerates, breccias, and diamictites with abundant volcanic material. In this work we present sedimentological, morphoscopic, petrographic, and geochemical data on pyroclasts recovered from core AND-2A, which provide insights on eruption styles, volcanic sources, and environments of deposition. One pyroclastic fall deposit, 12 resedimented volcaniclastic deposits and 14 volcanogenic sedimentary deposits record a history of intense explosive volcanic activity in southern Victoria Land during the Early Miocene. Tephra were ejected during Subplinian and Plinian eruptions fed by trachytic to rhyolitic magmas and during Strombolian to Hawaiian eruptions fed by basaltic to mugearitic magmas in submarine/subglacial to subaerial environments. The long-lived Mt. Morning eruptive centre, located c. 80 km south of the drillsite, was recognized as the probable volcanic source for these products on the basis of volcanological, geochemical, and age constraints. The study of tephra in the AND-2A core provides important paleoenvironment information by revealing that the deposition of primary and moderately reworked tephra occurred in a proglacial setting under generally open water marine conditions

The Complete Star Formation History of the Universe

The determination of the star-formation history of the Universe is a key goal of modern cosmology, as it is crucial to our understanding of how structure in the Universe forms and evolves. A picture has built up over recent years, piece-by-piece, by observing young stars in distant galaxies at different times in the past. These studies indicated that the stellar birthrate peaked some 8 billion years ago, and then declined by a factor of around ten to its present value. Here we report on a new study which obtains the complete star formation history by analysing the fossil record of the stellar populations of 96545 nearby galaxies. Broadly, our results support those derived from high-redshift galaxies elsewhere in the Universe. We find, however, that the peak of star formation was more recent - around 5 billion years ago. Our study also shows that the bigger the stellar mass of the galaxy, the earlier the stars were formed. This striking result indicates a very different formation history for high- and low-mass formation.Comment: Accepted by Nature. Press embargo until publishe

40Ar--39Ar dating of volcanogenic products from the AND-2A core (ANDRILL Southern McMurdo Sound Project, Antarctica): correlations with the Erebus Volcanic Province and implications for the age model of the core

The AND-2A drillcore (Antarctic Drilling Program – ANDRILL) was successfully completed in late 2007 on the Antarctic continental margin (southern McMurdo Sound, Ross Sea) with the aim of tracking ice-proximal to shallow marine environmental fluctuations and to document the 20-Ma evolution of the Erebus Volcanic Province. Lava clasts and tephra layers from the AND-2A drillcore were investigated from a petrographic and stratigraphic point of view and analyzed by the 40Ar–39Ar laser technique in order to constrain the age model of the core and to gain information on the style and nature of sediment deposition in the Victoria Land Basin since Early Miocene. Ten out of 17 samples yielded statistically robust 40Ar–39Ar ages, indicating that the AND-2A drillcore recovered !230 m of Middle Miocene (~128–358 meters below sea floor, ~11.5–16.0 Ma) and >780 m of Early Miocene (~358–1093 48 meters below sea floor, ~16.0–20.1 Ma). Results also highlight a nearly continuous stratigraphic record from at least 358 meters below sea floor down hole, characterized by a mean sedimentation rate of ~19 cm/ka, possible oscillations of no more than a few hundreds of ka and a break within ~17.5–18.1 Ma. Comparison with available data from volcanic deposits on land, suggests that volcanic rocks within the AND-2A core were supplied from the south, possibly with source areas closer to the drill site for the upper core levels, and from 358 meters below sea floor down hole, with the “proto-Mount Morning” as the main source

Questioning the application of risk of bias tools in appraising evidence from natural experimental studies: critical reflections on Benton et al., IJBNPA 2016.

We recently read the article by Benton et al. which reviewed risk of bias in natural experimental studies investigating the impact of the built environment on physical activity (Benton et al., 2016; Int J Behav Nutr Phys Act 13:107). As a technical exercise in assessing risk of bias to understand study quality, we found the results of this study both interesting and potentially useful. However, it prompted a number of concerns with the use of risk of bias tools for assessing the quality of evidence from studies exploiting natural experiments. As we discuss in this commentary, the rigid application of such tools could have adverse effects on the uptake and use of natural experiments in population health research and practice

Magnitude and Sign Correlations in Heartbeat Fluctuations

We propose an approach for analyzing signals with long-range correlations by decomposing the signal increment series into magnitude and sign series and analyzing their scaling properties. We show that signals with identical long-range correlations can exhibit different time organization for the magnitude and sign. We find that the magnitude series relates to the nonlinear properties of the original time series, while the sign series relates to the linear properties. We apply our approach to the heartbeat interval series and find that the magnitude series is long-range correlated, while the sign series is anticorrelated and that both magnitude and sign series may have clinical applications.Comment: 4 pages,late