6,034 research outputs found

    Temperature influence on the carbon isotopic composition of Orbulina universa and Globigerina bulloides (planktonic foraminifera)

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    Laboratory experiments with the planktonic foraminifera Orbulina universa (symbiotic) and Globigerina bulloides (nonsymbiotic) were used to examine the effects of temperature, irradiance (symbiont photosynthesis), [CO32-], [HPO42-], and ontogeny on shell d13C values. In ambient seawater ([CO32-] = 171 mmol kg-1), the d13C of O. universa shells grown under low light (LL) levels is insensitive to temperature and records the d13C value of seawater TCO2. In contrast, the d13C of high light (HL) shells increases ~0.4‰ across 15-25°C (+0.050‰/°C). This suggests that the d13C enrichment due to symbiont photosynthetic activity is temperature-dependent. A comparison of HL O. universa grown in elevated [CO32-] seawater with ambient specimens shows that temperature does not affect the slope of the d13C/[CO32-] relationship previously described [Spero et al., 1997]. The d13C of G. bulloides shells decreases across the 15-24°C temperature range and d13C:temperature slopes decrease with increasing shell size (-0.13, -0.10, and -0.09‰/°C in 11- 12-, and 13-chambered shells, respectively). The pattern of lower d13C values at higher temperatures likely results from the incorporation of more respired CO2 into the shell at higher metabolic rates. The d13C of HL O. universa increases with increased seawater [HPO42-]

    The implementation of a home-based isometric wall squat intervention using ratings of perceived exertion to select and control exercise intensity: a pilot study in normotensive and pre-hypertensive adults.

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    Isometric exercise (IE) and isometric wall squat (IWS) training have been shown to be effective methods of reducing arterial blood pressure. However, most IE interventions require methodologies and equipment that could present a barrier to participation. Therefore, this study aimed to examine the effectiveness of an accessible RPE prescribed IWS intervention. Thirty normotensive and pre-hypertensive adults were randomly assigned to a control group or one of two 4-week home-based IWS intervention groups: the first group conducted IWS exercise where intensity was prescribed and monitored using RPE (RPE-EX), whilst the other used a previously validated HR prescription method (HR-EX). Resting and ambulatory heart rate (HR) and blood pressure (BP) were measured pre- and post-intervention. Minimum clinically important differences (MCID; - 5 mmHg) in SBP and/or DBP were shown in 100% of intervention participants. Statistically significant reductions were shown in resting seated BP (RPE-EX: SBP: - 9 ± 6, DBP: - 6 ± 4, MAP: - 6 ± 3 mmHg; HR-EX: SBP: - 14 ± 6, DBP: - 6 ± 4, MAP: - 8 ± 4 mmHg), supine BP (RPE-EX: SBP: - 8 (- 5), DBP: - 8 (- 7), MAP: - 8 (- 4) mmHg; HR-EX: SBP: - 5 (- 4), MAP - 5 (- 4) mmHg), and ambulatory SBP (RPE-EX: - 8 ± 6 mmHg; HR-EX: - 10 ± 4 mmHg) following the interventions. There were no statistically significant differences between intervention groups in the magnitude of BP reduction. RPE prescribed IWS exercise can provide an effective and more accessible method for reducing BP at home, providing reductions comparable to the current HR-based prescription method. [Abstract copyright: © 2023. The Author(s).

    Mendocino power plant site ecological study final report

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    A preoperational ecological study of a proposed nuclear power plant site on the Mendocino County coast was initiated in September 1971. The study resulted from an agreement between the Pacific Gas and Electric Company and the California Department of Fish and Game signed in July 1971. In the agreement, Pacific Gas and Electric Company provided funds for the Department's studies of the site. Studies of the subtidal animal and plant communities were conducted by divers from September 1971 through March 1973; intertidal animal and plant populations were surveyed from November 1971 through February 1973. Sportfisheries for abalone and finfish were surveyed during 1972 and Spring of 1973. Stomach contents of many of the more abundant subtidal and intertidal fishes were examined. All of these studies were designed to determine the dominant species of plants, invertebrates and fishes in the various communities, their relative abundance, and where applicable, size composition, predators and competitors. The parameters developed from these studies would be used for comparison with similar studies conducted after the proposed plant went into operation to determine what effect construction and operation of the plant might have on the various plants and animals studied. (291pp.

    Fluctuations of a Greenlandic tidewater glacier driven by changes in atmospheric forcing : observations and modelling of Kangiata Nunaata Sermia, 1859–present

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    Acknowledgements. The authors wish to thank Stephen Price, Mauri Pelto, and the anonymous reviewer for their reviews and comments that helped to improve the manuscript. RACMO2.1 data were provided by Jan van Angelen and Michiel van den Broeke, IMAU, Utrecht University. MAR v3.2 data used for runoff calculations were provided by Xavier Fettweis, Department of Geography, University of Liège. The photogrammetric DEM used in Figs. 1 and 3 was provided by Kurt H. Kjær, Centre for GeoGenetics, University of Copenhagen. This research was financially supported by J. M. Lea’s PhD funding, NERC grant number NE/I528742/1. Support for F. M. Nick was provided through the Conoco-Phillips/Lundin Northern Area Program CRIOS project (Calving Rates and Impact on Sea Level).Peer reviewedPublisher PD

    Supervision and Scholarly Writing: Writing to Learn - Learning to Write

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    This paper describes an action research project on postgraduate students’ scholarly writing in which I employed reflective approaches to examine and enhance my postgraduate supervisory practice. My reflections on three distinct cycles of supervision illustrate a shift in thinking about scholarly writing and an evolving understanding of how to support postgraduate students’ writing. These understandings provide the foundation for a future-oriented fourth cycle of supervisory practice, which is characterised by three principles, namely the empowerment of students as writers, the technological context of contemporary writing, and ethical issues in writing

    Sorting of chromosomes by magnetic separation

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    Chromosomes were isolated from Chinese hamster x human hybrid cell lines containing four and nine human chromosomes. Human genomic DNA was biotinylated by nick translation and used to label the human chromosomes by in situ hybridization in suspension. Streptavidin was covalently coupled to the surface of magnetic beads and these were incubated with the hybridized chromosomes. The human chromosomes were bound to the magnetic beads through the strong biotin-streptavidin complex and then rapidly separated from nonlabeled Chinese hamster chromosomes by a simple permanent magnet. The hybridization was visualized by additional binding of avidin-FITC (fluorescein) to the unoccupied biotinylated human DNA bound to the human chromosomes. After magnetic separation, up to 98% of the individual chromosomes attached to magnetic beads were classified as human chromosomes by fluorescence microscopy

    Retreating to nature : rethinking 'therapeutic landscapes'

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    There is a long history of removing oneself from ‘society’ in order to recuperate or repair. This paper considers a yoga and massage retreat in Southern Spain, and what opportunities this retreat experience might offer for recuperation and the creation of healthy bodies. The paper positions ‘nature’ as an active participant, and as ‘enrolled’ in the experiences of the retreat as a ‘therapeutic landscape’, and questions how and what particular aspects of yoga practice (in intimate relation with place) give rise to therapeutic experiences

    The California-Kepler Survey. III. A Gap in the Radius Distribution of Small Planets

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    The size of a planet is an observable property directly connected to the physics of its formation and evolution. We used precise radius measurements from the California-Kepler Survey (CKS) to study the size distribution of 2025 Kepler\textit{Kepler} planets in fine detail. We detect a factor of \geq2 deficit in the occurrence rate distribution at 1.5-2.0 R_{\oplus}. This gap splits the population of close-in (PP < 100 d) small planets into two size regimes: RP_P < 1.5 R_{\oplus} and RP_P = 2.0-3.0 R_{\oplus}, with few planets in between. Planets in these two regimes have nearly the same intrinsic frequency based on occurrence measurements that account for planet detection efficiencies. The paucity of planets between 1.5 and 2.0 R_{\oplus} supports the emerging picture that close-in planets smaller than Neptune are composed of rocky cores measuring 1.5 R_{\oplus} or smaller with varying amounts of low-density gas that determine their total sizes.Comment: Paper III in the California-Kepler Survey series, accepted to the Astronomical Journa
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