Laurentian University

Observations of neutral-current $\ensuremath{\nu}$ interactions on deuterium in the Sudbury Neutrino Observatory are reported. Using the neutral current (NC), elastic scattering, and charged current reactions and assuming the standard ${}^{8}\mathrm{B}$ shape, the ${\ensuremath{\nu}}_{e}$ component of the ${}^{8}\mathrm{B}$ solar flux is ${\ensuremath{\varphi}}_{e}{\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.76}_{\ensuremath{-}0.05}^{+0.05}(\mathrm{stat}{)}_{\ensuremath{-}0.09}^{+0.09}(\mathrm{syst})\ifmmode\times\else\texttimes\fi{}{10}^{6}\phantom{\rule{0ex}{0ex}}{\mathrm{cm}}^{\ensuremath{-}2}{\mathrm{s}}^{\ensuremath{-}1}$ for a kinetic energy threshold of 5 MeV. The non- ${\ensuremath{\nu}}_{e}$ component is ${\ensuremath{\varphi}}_{\ensuremath{\mu}\ensuremath{\tau}}{\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}3.41}_{\ensuremath{-}0.45}^{+0.45}(\mathrm{stat}{)}_{\ensuremath{-}0.45}^{+0.48}(\mathrm{syst})\ifmmode\times\else\texttimes\fi{}{10}^{6}\phantom{\rule{0ex}{0ex}}{\mathrm{cm}}^{\ensuremath{-}2}{\mathrm{s}}^{\ensuremath{-}1}$, $5.3\ensuremath{\sigma}$ greater than zero, providing strong evidence for solar ${\ensuremath{\nu}}_{e}$ flavor transformation. The total flux measured with the NC reaction is ${\ensuremath{\varphi}}_{\mathrm{NC}}{\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}5.09}_{\ensuremath{-}0.43}^{+0.44}(\mathrm{stat}{)}_{\ensuremath{-}0.43}^{+0.46}(\mathrm{syst})\ifmmode\times\else\texttimes\fi{}{10}^{6}\phantom{\rule{0ex}{0ex}}{\mathrm{cm}}^{\ensuremath{-}2}{\mathrm{s}}^{\ensuremath{-}1}$, consistent with solar models.

Qualitative research has grown within sport and exercise psychology and is now widely conducted. The purpose of this review is to discuss three commonly used ways to demonstrate rigor when conducting or judging qualitative research in sport and exercise psychology. These are the method of member checking, the method of inter-rater reliability, and the notion of universal criteria. Problems with each method are first highlighted. Member checking and inter-rater reliability are shown to be ineffective for verification, trustworthiness, or reliability purposes. Next, universal criteria within the context of Tracy’s, heavily drawn on paper within sport and exercise psychology is problematized. Throughout the discussion of each method and universal criteria more suitable possibilities for conducting rigorous qualitative research are offered. The paper concludes that to support high-quality qualitative research, scholars – including journal editors and reviewers – need to change how rigor is developed and judged, rather than perpetuate the problems with how it has been commonly evaluated in the past. Recommendations for developing rigor when conducting and/or judging qualitative research within sport and exercise psychology are also offered.

Solar neutrinos from ${}^{8}\mathrm{B}$ decay have been detected at the Sudbury Neutrino Observatory via the charged current (CC) reaction on deuterium and the elastic scattering (ES) of electrons. The flux of ${\ensuremath{\nu}}_{e}$'s is measured by the CC reaction rate to be ${\ensuremath{\varphi}}^{\mathrm{CC}}({\ensuremath{\nu}}_{e})\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.75\ifmmode\pm\else\textpm\fi{}0.07(\mathrm{stat}{)}_{\ensuremath{-}0.11}^{+0.12}(\mathrm{syst})\ifmmode\pm\else\textpm\fi{}0.05(\mathrm{theor})\ifmmode\times\else\texttimes\fi{}{10}^{6}{\mathrm{cm}}^{\ensuremath{-}2}{\mathrm{s}}^{\ensuremath{-}1}$. Comparison of ${\ensuremath{\varphi}}^{\mathrm{CC}}({\ensuremath{\nu}}_{e})$ to the Super-Kamiokande Collaboration's precision value of the flux inferred from the ES reaction yields a $3.3\ensuremath{\sigma}$ difference, assuming the systematic uncertainties are normally distributed, providing evidence of an active non- ${\ensuremath{\nu}}_{e}$ component in the solar flux. The total flux of active ${}^{8}\mathrm{B}$ neutrinos is determined to be $5.44\ifmmode\pm\else\textpm\fi{}0.99\ifmmode\times\else\texttimes\fi{}{10}^{6}{\mathrm{cm}}^{\ensuremath{-}2}{\mathrm{s}}^{\ensuremath{-}1}$.

While there is a general sense that lakes can act as sentinels of climate change, their efficacy has not been thoroughly analyzed. We identified the key response variables within a lake that act as indicators of the effects of climate change on both the lake and the catchment. These variables reflect a wide range of physical, chemical, and biological responses to climate. However, the efficacy of the different indicators is affected by regional response to climate change, characteristics of the catchment, and lake mixing regimes. Thus, particular indicators or combinations of indicators are more effective for different lake types and geographic regions. The extraction of climate signals can be further complicated by the influence of other environmental changes, such as eutrophication or acidification, and the equivalent reverse phenomena, in addition to other land-use influences. In many cases, however, confounding factors can be addressed through analytical tools such as detrending or filtering. Lakes are effective sentinels for climate change because they are sensitive to climate, respond rapidly to change, and integrate information about changes in the catchment.

One metabolic equivalent (MET) is defined as the amount of oxygen consumed while sitting at rest and is equal to 3.5 ml O2 per kg body weight x min. The MET concept represents a simple, practical, and easily understood procedure for expressing the energy cost of physical activities as a multiple of the resting metabolic rate. The energy cost of an activity can be determined by dividing the relative oxygen cost of the activity (ml O2/kg/min) x by 3.5. This article summarizes and presents energy expenditure values for numerous household and recreational activities in both METS and watts units. Also, the intensity levels (in METS) for selected exercise protocols are compared stage by stage. In spite of its limitations, the MET concept provides a convenient method to describe the functional capacity or exercise tolerance of an individual as determined from progressive exercise testing and to define a repertoire of physical activities in which a person may participate safely, without exceeding a prescribed intensity level.

Evidence-based practice includes, in part, implementation of the findings of well-conducted quality research studies. So being able to critique quantitative research is an important skill for nurses. Consideration must be given not only to the results of the study but also the rigour of the research. Rigour refers to the extent to which the researchers worked to enhance the quality of the studies. In quantitative research, this is achieved through measurement of the validity and reliability.1 Validity is defined as the extent to which a concept is accurately measured in a quantitative study. For example, a survey designed to explore depression but which actually measures anxiety would not be considered valid. The second measure of quality in a quantitative study is reliability , or the accuracy of an instrument. In other words, the extent to which a research instrument consistently has the same results if it is used in the same situation on repeated occasions. A simple example of validity and reliability is an alarm clock that rings at 7:00 each morning, but is set for 6:30. It is very reliable (it consistently rings the same time each day), but is not valid (it is not ringing at the desired time). It's important to consider validity and reliability of the data collection tools (instruments) when either conducting or critiquing research. There are three major types of validity. These are described in table 1. View this table: Table 1 Types of validity The first category is content validity . This category looks at whether the instrument adequately covers …

Abstract In this first worldwide synthesis of in situ and satellite‐derived lake data, we find that lake summer surface water temperatures rose rapidly (global mean = 0.34°C decade −1 ) between 1985 and 2009. Our analyses show that surface water warming rates are dependent on combinations of climate and local characteristics, rather than just lake location, leading to the counterintuitive result that regional consistency in lake warming is the exception, rather than the rule. The most rapidly warming lakes are widely geographically distributed, and their warming is associated with interactions among different climatic factors—from seasonally ice‐covered lakes in areas where temperature and solar radiation are increasing while cloud cover is diminishing (0.72°C decade −1 ) to ice‐free lakes experiencing increases in air temperature and solar radiation (0.53°C decade −1 ). The pervasive and rapid warming observed here signals the urgent need to incorporate climate impacts into vulnerability assessments and adaptation efforts for lakes.

Concerns about secondary use of data and limited opportunities for benefit-sharing have focused attention on the tension that Indigenous communities feel between (1) protecting Indigenous rights and interests in Indigenous data (including traditional knowledges) and (2) supporting open data, machine learning, broad data sharing, and big data initiatives. The International Indigenous Data Sovereignty Interest Group (within the Research Data Alliance) is a network of nation-state based Indigenous data sovereignty networks and individuals that developed the ‘CARE Principles for Indigenous Data Governance’ (Collective Benefit, Authority to Control, Responsibility, and Ethics) in consultation with Indigenous Peoples, scholars, non-profit organizations, and governments. The CARE Principles are people– and purpose-oriented, reflecting the crucial role of data in advancing innovation, governance, and self-determination among Indigenous Peoples. The Principles complement the existing data-centric approach represented in the ‘FAIR Guiding Principles for scientific data management and stewardship’ (Findable, Accessible, Interoperable, Reusable). The CARE Principles build upon earlier work by the Te Mana Raraunga Maori Data Sovereignty Network, US Indigenous Data Sovereignty Network, Maiam nayri Wingara Aboriginal and Torres Strait Islander Data Sovereignty Collective, and numerous Indigenous Peoples, nations, and communities. The goal is that stewards and other users of Indigenous data will ‘Be FAIR and CARE.’ In this first formal publication of the CARE Principles, we articulate their rationale, describe their relation to the FAIR Principles, and present examples of their application.

Body condition can have important fitness consequences, but measuring body condition of live animals from wild populations has been the subject of much recent debate. Using the residuals from a regression of body mass on a linear measure of body size is one of the most common methods of measuring condition and has been used in many vertebrate taxa. Recently, the use of this method has been criticized because assumptions are likely violated. We tested several assumptions regarding the use of this method with body composition and morphometric data from five species of small mammals and with statistical simulations. We tested the assumptions that the relationship between body mass and body size is linear, and that the proportion of mass associated with energy reserves is independent of body size. In addition, we tested whether the residuals from reduced major axis (RMA) regression or major axis (MA) regression performed better than the residuals from ordinary least squares (OLS) regression as indices of body condition. We found no evidence of nonlinear relationships between body mass and body size. Relative energy reserves (fat and lean dry mass) were generally independent or weakly dependent on body size. Residuals from MA and RMA regression consistently explained less variation in body composition than OLS regression. Using statistical simulations, we compared the effects of violations of the assumption that true condition and residual indices are independent of body size on the OLS, MA, and RMA procedures and found that OLS performed better than the RMA and MA procedures. Despite recent criticisms of residuals from mass–size OLS regressions, these indices of body condition appear to satisfy critical assumptions. Although some caution is warranted when using residuals, especially when both interindividual variation in body size and measurement error are high, we found no reason to reject OLS residuals as legitimate indices of body condition.

The Sudbury Neutrino Observatory (SNO) has measured day and night solar neutrino energy spectra and rates. For charged current events, assuming an undistorted ${}^{8}\mathrm{B}$ spectrum, the night minus day rate is $14.0%\ifmmode\pm\else\textpm\fi{}6.3{%}_{\ensuremath{-}1.4}^{+1.5}%$ of the average rate. If the total flux of active neutrinos is additionally constrained to have no asymmetry, the ${\ensuremath{\nu}}_{e}$ asymmetry is found to be $7.0%\ifmmode\pm\else\textpm\fi{}4.9{%}_{\ensuremath{-}1.2}^{+1.3}%$. A global solar neutrino analysis in terms of matter-enhanced oscillations of two active flavors strongly favors the large mixing angle solution.

VizualAge, a new computer software tool for analysing U‐Pb data obtained by laser ablation‐inductively coupled plasma‐mass spectrometry, was developed. It consists of a data reduction scheme (DRS) for Iolite (a general mass spectrometry data analysis tool) as well as visualisation routines. In addition to the U/Pb and Th/Pb ages calculated by Iolite’s U‐Pb geochronology DRS, VizualAge also calculates 207 Pb/ 206 Pb ages and common Pb corrections for each time‐slice of raw data. Importantly, VizualAge allows one to display a live concordia diagram for visualising data on such a diagram as an integration interval is being adjusted. This provides instantaneous feedback regarding discordance, uncertainty, error correlation and common Pb. Several zircon data sets were used to illustrate how the live concordia could be used as a powerful inspection tool, revealing a single analysis to consist of zones of concordance, metamict areas, as well as inherited cores or younger overgrowths. VizualAge also constructs histograms, conventional and Tera‐Wasserburg type concordia diagrams, as well as 3D U‐Th‐Pb and total U‐Pb concordia diagrams. The precision and accuracy of data reduced with VizualAge are demonstrated with examples of the Plešovice, Temora‐2 and Penglai zircon reference materials. Data for zircon from the Long Lake Batholith (Wyoming craton) were used to illustrate how VizualAge calculated common Pb corrections and helped to expose as yet unexplained difficulties with accurately determining 204 Pb.

Several methods have been developed to assess the thermal state of the mantle below oceanic ridges, islands, and plateaus, on the basis of the petrology and geochemistry of erupted lavas. One leads to the conclusion that mantle potential temperature (i.e., T P ) of ambient mantle below oceanic ridges is 1430°C, the same as Hawaii. Another has ridges with a large range in ambient mantle potential temperature (i.e., T P = 1300–1570°C), comparable in some cases to hot spots (Klein and Langmuir, 1987; Langmuir et al., 1992). A third has uniformly low temperatures for ambient mantle below ridges, ∼1300°C, with localized 250°C anomalies associated with mantle plumes. All methods involve assumptions and uncertainties that we critically evaluate. A new evaluation is made of parental magma compositions that would crystallize olivines with the maximum forsterite contents observed in lava flows. These are generally in good agreement with primary magma compositions calculated using the mass balance method of Herzberg and O'Hara (2002), and differences reflect the well‐known effects of fractional crystallization. Results of primary magma compositions we obtain for mid‐ocean ridge basalts and various oceanic islands and plateaus generally favor the third type of model but with ambient mantle potential temperatures in the range 1280–1400°C and thermal anomalies that can be 200–300°C above this background. Our results are consistent with the plume model.

We review research and theory on the HEXACO personality dimensions of Honesty-Humility (H), Agreeableness (A), and Emotionality (E), with particular attention to the following topics: (1) the origins of the HEXACO model in lexical studies of personality structure, and the content of the H, A, and E factors in those studies; (2) the operationalization of the H, A, and E factors in the HEXACO Personality Inventory-Revised; (3) the construct validity of self-reports on scales measuring the H factor; (4) the theoretical distinction between H and A; (5) similarity and assumed similarity between social partners in personality, with a focus on H and A; (6) the extent to which H (and A and E) variance is represented in instruments assessing the "Five-Factor Model" of personality; and (7) the relative validity of scales assessing the HEXACO and Five-Factor Model dimensions in predicting criteria conceptually relevant to H, A, and E.

The Sudbury Neutrino Observatory has precisely determined the total active (${\ensuremath{\nu}}_{x}$) $^{8}\mathrm{B}$ solar neutrino flux without assumptions about the energy dependence of the ${\ensuremath{\nu}}_{e}$ survival probability. The measurements were made with dissolved NaCl in heavy water to enhance the sensitivity and signature for neutral-current interactions. The flux is found to be $5.21\ifmmode\pm\else\textpm\fi{}0.27\mathrm{(}\mathrm{stat}\mathrm{)}\ifmmode\pm\else\textpm\fi{}0.38\mathrm{(}\mathrm{syst}\mathrm{)}\ifmmode\times\else\texttimes\fi{}{10}^{6}\text{ }{\mathrm{cm}}^{\ensuremath{-}2}\text{ }\text{ }{\mathrm{s}}^{\ensuremath{-}1}$, in agreement with previous measurements and standard solar models. A global analysis of these and other solar and reactor neutrino results yields $\ensuremath{\Delta}{m}^{2}={7.1}_{\ensuremath{-}0.6}^{+1.2}\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}\text{ }{\mathrm{eV}}^{2}$ and $\ensuremath{\theta}={32.5}_{\ensuremath{-}2.3}^{+2.4}$ degrees. Maximal mixing is rejected at the equivalent of 5.4 standard deviations.

A 14.6-kilogram sodium-doped CsI scintillator is used to detect a neutrino scattering process with a 6.7σ confidence level.

The effects of plants on the biosphere, atmosphere and geosphere are key determinants of terrestrial ecosystem functioning. However, despite substantial progress made regarding plant belowground components, we are still only beginning to explore the complex relationships between root traits and functions. Drawing on the literature in plant physiology, ecophysiology, ecology, agronomy and soil science, we reviewed 24 aspects of plant and ecosystem functioning and their relationships with a number of root system traits, including aspects of architecture, physiology, morphology, anatomy, chemistry, biomechanics and biotic interactions. Based on this assessment, we critically evaluated the current strengths and gaps in our knowledge, and identify future research challenges in the field of root ecology. Most importantly, we found that belowground traits with the broadest importance in plant and ecosystem functioning are not those most commonly measured. Also, the estimation of trait relative importance for functioning requires us to consider a more comprehensive range of functionally relevant traits from a diverse range of species, across environments and over time series. We also advocate that establishing causal hierarchical links among root traits will provide a hypothesis-based framework to identify the most parsimonious sets of traits with the strongest links on functions, and to link genotypes to plant and ecosystem functioning.

Microorganisms are vital in mediating the earth’s biogeochemical cycles; yet, despite our rapidly increasing ability to explore complex environmental microbial communities, the relationship between microbial community structure and ecosystem processes remains poorly understood. Here, we address a fundamental and unanswered question in microbial ecology: ‘When do we need to understand microbial community structure to accurately predict function?’ We present a statistical analysis investigating the value of environmental data and microbial community structure independently and in combination for explaining rates of carbon and nitrogen cycling processes within 82 global datasets. Environmental variables were the strongest predictors of process rates but left 44% of variation unexplained on average, suggesting the potential for microbial data to increase model accuracy. Although only 29% of our datasets were significantly improved by adding information on microbial community structure, we observed improvement in models of processes mediated by narrow phylogenetic guilds via functional gene data, and conversely, improvement in models of facultative microbial processes via community diversity metrics. Our results also suggest that microbial diversity can strengthen predictions of respiration rates beyond microbial biomass parameters, as 53% of models were improved by incorporating both sets of predictors compared to 35% by microbial biomass alone. Our analysis represents the first comprehensive analysis of research examining links between microbial community structure and ecosystem function. Taken together, our results indicate that a greater understanding of microbial communities informed by ecological principles may enhance our ability to predict ecosystem process rates relative to assessments based on environmental variables and microbial physiology.

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In the context of a recent massive increase in research on plant root functions and their impact on the environment, root ecologists currently face many important challenges to keep on generating cutting-edge, meaningful and integrated knowledge. Consideration of the below-ground components in plant and ecosystem studies has been consistently called for in recent decades, but methodology is disparate and sometimes inappropriate. This handbook, based on the collective effort of a large team of experts, will improve trait comparisons across studies and integration of information across databases by providing standardised methods and controlled vocabularies. It is meant to be used not only as starting point by students and scientists who desire working on below-ground ecosystems, but also by experts for consolidating and broadening their views on multiple aspects of root ecology. Beyond the classical compilation of measurement protocols, we have synthesised recommendations from the literature to provide key background knowledge useful for: (1) defining below-ground plant entities and giving keys for their meaningful dissection, classification and naming beyond the classical fine-root vs coarse-root approach; (2) considering the specificity of root research to produce sound laboratory and field data; (3) describing typical, but overlooked steps for studying roots (e.g. root handling, cleaning and storage); and (4) gathering metadata necessary for the interpretation of results and their reuse. Most importantly, all root traits have been introduced with some degree of ecological context that will be a foundation for understanding their ecological meaning, their typical use and uncertainties, and some methodological and conceptual perspectives for future research. Considering all of this, we urge readers not to solely extract protocol recommendations for trait measurements from this work, but to take a moment to read and reflect on the extensive information contained in this broader guide to root ecology, including sections I-VII and the many introductions to each section and root trait description. Finally, it is critical to understand that a major aim of this guide is to help break down barriers between the many subdisciplines of root ecology and ecophysiology, broaden researchers' views on the multiple aspects of root study and create favourable conditions for the inception of comprehensive experiments on the role of roots in plant and ecosystem functioning.

Research Article| April 01, 1994 Bathymetric and isotopic evidence for a short-lived Late Ordovician glaciation in a greenhouse period P. J. Brenchley; P. J. Brenchley 1Department of Earth Sciences, University of Liverpool, Liverpool L69 3BX, United Kingdom Search for other works by this author on: GSW Google Scholar J. D. Marshall; J. D. Marshall 1Department of Earth Sciences, University of Liverpool, Liverpool L69 3BX, United Kingdom Search for other works by this author on: GSW Google Scholar G. A. F. Carden; G. A. F. Carden 1Department of Earth Sciences, University of Liverpool, Liverpool L69 3BX, United Kingdom Search for other works by this author on: GSW Google Scholar D. B. R. Robertson; D. B. R. Robertson 1Department of Earth Sciences, University of Liverpool, Liverpool L69 3BX, United Kingdom Search for other works by this author on: GSW Google Scholar D. G. F. Long; D. G. F. Long 2Department of Geology, Laurentian University, Sudbury, Ontario, P3E 2C6, Canada Search for other works by this author on: GSW Google Scholar T. Meidla; T. Meidla 3Institute of Geology, Tartu University, Tartu, EE2400, Estonia Search for other works by this author on: GSW Google Scholar L. Hints; L. Hints 4Institute of Geology, Academy of Sciences, Tallinn, EE0105 Estonia Search for other works by this author on: GSW Google Scholar T. F. Anderson T. F. Anderson 5Department of Geology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 Search for other works by this author on: GSW Google Scholar Author and Article Information P. J. Brenchley 1Department of Earth Sciences, University of Liverpool, Liverpool L69 3BX, United Kingdom J. D. Marshall 1Department of Earth Sciences, University of Liverpool, Liverpool L69 3BX, United Kingdom G. A. F. Carden 1Department of Earth Sciences, University of Liverpool, Liverpool L69 3BX, United Kingdom D. B. R. Robertson 1Department of Earth Sciences, University of Liverpool, Liverpool L69 3BX, United Kingdom D. G. F. Long 2Department of Geology, Laurentian University, Sudbury, Ontario, P3E 2C6, Canada T. Meidla 3Institute of Geology, Tartu University, Tartu, EE2400, Estonia L. Hints 4Institute of Geology, Academy of Sciences, Tallinn, EE0105 Estonia T. F. Anderson 5Department of Geology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1994) 22 (4): 295–298. https://doi.org/10.1130/0091-7613(1994)022<0295:BAIEFA>2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation P. J. Brenchley, J. D. Marshall, G. A. F. Carden, D. B. R. Robertson, D. G. F. Long, T. Meidla, L. Hints, T. F. Anderson; Bathymetric and isotopic evidence for a short-lived Late Ordovician glaciation in a greenhouse period. Geology 1994;; 22 (4): 295–298. doi: https://doi.org/10.1130/0091-7613(1994)022<0295:BAIEFA>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract The end Ordovician glaciation is distinct among Phanerozoic glaciations in that CO2, levels were generally high, yet major continental ice sheets accumulated on the Gondwana supercontinent. New oxygen isotopic data indicate substantial changes in sea-water temperatures and ice volume coinciding with glacio-eustatic changes in sea level reflecting the growth and decay of the Gondwana ice cap. Major glaciation was apparently confined to the Hirnantian and was 0.5-1 m.y. long, rather than the 35 m.y. of earlier estimates. Carbon isotope values indicate significant changes in carbon cycling as the oceans changed from a state with warm saline bottom waters to a state with cold deep-water circulation and then back again. We believe that the changes in the carbon cycle effected a reduction in PCO2 levels in the oceans and atmosphere and thus promoted glaciation but were unable to sustain icehouse conditions in a greenhouse world. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.