2,281 research outputs found
Assessing lake eutrophication using chironomids: understanding the nature of community response in different lake types
No full text1. Total phosphorus (TP) and chlorophyll a (Chl a) chironomid inference models (Brodersen & Lindegaard, 1999; Brooks, Bennion & Birks, 2001) were used in an attempt to reconstruct changes in nutrients from three very different lake types. Both training sets were expanded, particularly at the low end of the nutrient gradient, using contemporary chironomid assemblages and environmental parameters from 12 British lakes, although this had little improvement on the model performances.2. Dissimilarity analyses showed that the historic chironomid assemblages did not have good analogues in the original calibration or extended datasets. However, since the transfer functions are based on weighted averages of the trophic optima for the taxa present and not on community similarities, reasonable downcore inferences were produced. Ordination analyses also showed that the lakes retain their 'identity' over time, as the sample dissimilarities within lakes were less than the dissimilarities between lakes.3. Analysis of the three historic lake profiles showed a range of chironomid community responses to lake development. Chironomids from a shallow lake, Slapton Ley, responded indirectly to nutrient enrichment (TP), probably through altered substrate, macrophyte and fish conditions, rather than directly to primary productivity (Chl a). A stratified lake, Old Mill Reservoir, showed a loss of the profundal chironomid fauna due to increasing primary productivity (Chl a) coupled with increasing hypoxia. A response to nutrients (TP or total nitrogen (TN)) at this site is also indirect, and the TP reconstruction therefore cannot be reliably interpreted. The third lake, March Ghyll Reservoir has little change in historic chironomid communities, suggesting that this well mixed, relatively unproductive lake has changed less than the other lakes.4. Using chironomids to reconstruct nutrient histories does not follow a simple scheme. The response to changes in nutrients may be direct, but mediated through other ecosystem components. As alternative stable states are possible at a given level of TP it is also likely that alternative chironomid communities exist under similar nutrient conditions. Changes in biological communities can thus occur over thresholds, and it is only biological proxies that can reflect such ecosystem switches within palaeoenvironmental investigations
iPods in early childhood: Mobile technologies and story telling
Get PDFMobile technologies are making inroads in many aspects of education. The potential of many of these devices is being explored in a range of educational environments but early childhood educators are not commonly early adopters of these new technologies. This paper examines the process and impact of iPods on these students’ creation of original digital stories to support their understanding of how young children learn. The pedagogical approach is described in detail together with observations on the process, lessons learned, and extensions of the activity into other discipline areas
Evaluating Research Impact through Open Access to Scholarly Communication
Get PDFScientific research is a competitive business – in order to secure funding, promotion and tenure researchers must demonstrate their work has impact in their field. To maximise impact researchers undertake high priority research, aim to get results first, and publish in the highest impact journals. The Internet now presents a new opportunity to the scholarly author seeking higher impact: s/he can now make their work instantly accessible on the Web through author self-archiving. This growing body of open access literature (coupled with new publishing models that make journals available for-free to the reader) maximises research impact by maximising the number of people who can read it, and making it available sooner. Open access also provides a new opportunity for bibliometric research. This thesis describes the relatively recent phenomenon of open access to research literature, tools that were built to collect and analyse that literature, and the results of analyses of the effect of open access and its effect on author behaviour. It shows that articles self-archived by authors receive between 50-250% more citations, that rapid pre-printing on the Web has dramatically reduced the peak citation rate from over a year to virtually instant and how citation-impact – now widely used for evaluation – can be expanded to include a new web metric of download impact
Resistance- and endurance-trained young men display comparable carotid artery strain parameters that are superior to untrained men.
Get PDFThis article is licensed under a Creative Commons Attri bution 4.0 International License, which permits use, sharing, adapta tion, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/Purpose: Central arterial stiffness, a predictor of cardiovascular risk, attenuates with endurance-exercise in ageing populations. However, in young individuals, this effect is inconsistent and emerging evidence suggests resistance-exercise may increase arterial stiffness. Two-dimensional (2D)-Strain imaging of the common carotid artery (CCA) is more sensitive at detecting endurance-training induced alterations in CCA stiffness than conventional methods, but has not been used to examine CCA stiffness in young resistance-trained individuals. Therefore, we compared CCA 2D-Strain parameters at rest, during acute exercise and recovery between resistance-trained, endurance-trained, and untrained young men.
Methods: Short-axis CCA ultrasound images were obtained from 12 endurance-trained [27yrs (95%CI; 24-29)], 14 resistance-trained [24yrs (23-26)] and 12 untrained [23yrs (22-24] men at rest, during isometric handgrip (IHG) exercise and recovery. 2D-Strain analysis quantified CCA peak circumferential strain (PCS) and systolic (S-SR) and diastolic (D-SR) strain rates. Conventional stiffness indices included aortic pulse-wave velocity, CCA β-stiffness (β1) and Petersons elastic modulus (Ep).
Results: Resting conventional stiffness indices were not different between groups (P > 0.05). Resting PCS and S-SR were comparable between resistance- [11.6% (10.6-12.5) and 1.46 s-1 (1.37-1.55), respectively] and endurance-trained [11.4% (10.7-12.2) and 1.5 s-1 (1.38-1.62)] men and superior to untrained men [9.5% (9.19-9.9); P < 0.004 and 1.24 s-1 (1.17 - 1.31); P < 0.018)]. Both trained groups displayed comparable reductions in PCS and S-SR during IHG, which returned to resting values during recovery (P < 0.001), whereas these parameters remained unchanged in untrained men. D-SR decreased during IHG in all groups (P < 0.001), but to a lesser extent in endurance-trained men (P < 0.023), whereas β1 and Ep increased to a similar magnitude in all groups and returned to resting values during recovery (P < 0.001).
Conclusion: Resistance- and endurance-trained men display comparable CCA 2D-Strain parameters that are superior to untrained men, which contends previous reports that resistance-training increases CCA stiffness
An alternative suggestion for the Pliocene onset of major northern hemisphere glaciation based on the geochemical provenance of North Atlantic Ocean ice-rafted debris
No full textThe onset of abundant ice-rafted debris (IRD) deposition in the Nordic Seas and subpolar North Atlantic Ocean 2.72 millions of years ago (Ma) is thought to record the Pliocene onset of major northern hemisphere glaciation (NHG) due to a synchronous advance of North American Laurentide, Scandinavian and Greenland ice-sheets to their marine calving margins during marine isotope stage (MIS) G6. Numerous marine and terrestrial records from the Nordic Seas region indicate that extensive ice sheets on Greenland and Scandinavia increased IRD inputs to these seas from 2.72 Ma. The timing of ice-sheet expansion on North America as tracked by IRD deposition in the subpolar North Atlantic Ocean, however, is less clear because both Europe and North America are potential sources for icebergs in this region. Moreover, cosmogenic-dating of terrestrial tills on North America indicate that the Laurentide Ice Sheet did not extend to ~39 ?N until 2.4 ± 0.14 Ma, at least 180 kyr after the onset of major IRD deposition at 2.72 Ma. To address this problem, we present the first detailed analysis of the geochemical provenance of individual sand- sized IRD deposited in the subpolar North Atlantic Ocean between MIS G6 to 100 (~2.72-2.52 Ma). IRD provenance is assessed using laser ablation lead (Pb) isotope analyses of single ice-rafted (>150?m) feldspar grains. To track when an ice-rafting setting consistent with major NHG first occurred in the North Atlantic Ocean during the Pliocene intensification of NHG (iNHG), we investigate when the Pb-isotope composition (206Pb/204Pb, 207Pb/204Pb, 208Pb/204Pb) of feldspars deposited at DSDP Site 611 first resembles that determined for IRD deposited at this site during MIS 100, the oldest glacial for which there exists convincing evidence for widespread glaciation of North America. Whilst Quaternary- magnitude IRD fluxes exist at Site 611 during glacials from 2.72 Ma, we find that the provenance of this IRD is not constant. Instead, we find that the Pb-isotope composition of IRD at our study site is not consistent with major NHG until MIS G2 (2.64 Ma). We hypothesise that IRD deposition in the North Atlantic Ocean prior to MIS G2 was dominated by iceberg calving from Greenland and Scandinavia. We further suggest that the grounding line of continental ice on Northeast America may not have extended onto the continental shelf and calved significant numbers of icebergs to the North Atlantic Ocean during glacials until 2.64 Ma
Transforming Power Relationships: Leadership, Risk, and Hope. IHS Political Science Series No. 135, May 2013
Get PDFChronic communal conflicts resemble the prisoner’s dilemma. Both communities prefer peace to war. But neither trusts the other, viewing the other’s gain as its own loss, so
potentially shared interests often go unrealized.
Achieving positive-sum outcomes from apparently zero-sum struggles requires a kind of riskembracing leadership. To succeed leaders must: a) see power relations as potentially
positive-sum; b) strengthen negotiating adversaries instead of weakening them; and c) demonstrate hope for a positive future and take great personal risks to achieve it.
Such leadership is exemplified by Nelson Mandela and F.W. de Klerk in the South African democratic transition. To illuminate the strategic dilemmas Mandela and de Klerk faced, we examine the work of Robert Axelrod, Thomas Schelling, and Josep Colomer, who highlight important dimensions of the problem but underplay the role of risk-embracing leadership. Finally we discuss leadership successes and failures in the Northern Ireland settlement and the Israeli-Palestinian conflict
Effect of changes in testing parameters on the cost-effectiveness of two pooled test methods to classify infection status of animals in a herd
No full textMonte Carlo simulation was used to determine optimal fecal pool sizes for identification of all Mycobacterium avium subsp. paratuberculosis (MAP)-infected cows in a dairy herd. Two pooling protocols were compared: a halving protocol involving a single retest of negative pools followed by halving of positive pools and a simple protocol involving single retest of negative pools but no halving of positive pools. For both protocols, all component samples in positive pools were then tested individually. In the simulations, the distributions of number of tests required to classify all individuals in an infected herd were generated for various combinations of prevalence (0.01, 0.05 and 0.1), herd size (300, 1000 and 3000), pool size (5, 10, 20 and 50) and test sensitivity (0.5–0.9). Test specificity was fixed at 1.0 because fecal culture for MAP yields no or rare false-positive results. Optimal performance was determined primarily on the basis of a comparison of the distributions of numbers of tests needed to detect MAP-infected cows using the Mann–Whitney U test statistic. Optimal pool size was independent of both herd size and test characteristics, regardless of protocol. When sensitivity was the same for each pool size, pool sizes of 20 and 10 performed best for both protocols for prevalences of 0.01 and 0.1, respectively, while for prevalences of 0.05, pool sizes of 10 and 20 were optimal for the simple and halving protocols, respectively. When sensitivity decreased with increasing pool size, the results changed for prevalences of 0.05 and 0.1 with pool sizes of 50 being optimal especially at a prevalence of 0.1. Overall, the halving protocol was more cost effective than the simple protocol especially at higher prevalences. For detection of MAP using fecal culture, we recommend use of the halving protocol and pool sizes of 10 or 20 when the prevalence is suspected to range from 0.01 to 0.1 and there is no expected loss of sensitivity with increasing pool size. If loss in sensitivity is expected and the prevalence is thought to be between 0.05 and 0.1, the halving protocol and a pool size of 50 is recommended. Our findings are broadly applicable to other infectious diseases under comparable testing conditions.ID: S0167587710000085; M3: Article; Accession Number: S0167587710000085; Author: Locksley L. McV. Messam (a, b); Author: Joshua M. O’Brien (c); Author: Sharon K. Hietala (d); Author: Ian A. Gardner (e, ⁎); Affiliation: St. Georges University, Department of Public Health and Preventive Medicine, School of Medicine, P.O. Box 7, True Blue, St. Georges, Grenada, West Indies; Affiliation: St. Georges University, Office of the Dean, School of Veterinary Medicine, P.O. Box 7, True Blue, St. George's, Grenada, West Indies; Affiliation: Center for Animal Disease Modeling and Surveillance, University of California, Davis, CA 95616, USA; Affiliation: California Animal Health and Food Safety Laboratory System, Davis, CA 95616, USA; Affiliation: Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA; Keyword: Cost-effectiveness; Keyword: Pooled testing; Keyword: Mycobacterium avium subsp. paratuberculosis; Keyword: Retesting; Number of Pages: 11; Language: English
Cold war theology: a controversial religious image of King James VI & I in England and on the Continent in 1603
No full textA former student of James Cameron’s, Ian Hazlett contributes a paper very much in the spirit of his teacher. It considers the afterlife of the King’s (or Negative) Confession, commissioned by James VI of Scotland in 1581 as a clear statement of his Calvinist credentials. By the time he gained the crown of England in 1603 however, his evolving religious views meant it had become a document he sought to distance himself from. Both Protestant and Catholic propagandists and publishers, keen to give a particular picture of the theological sympathies of the new English king, subsequently produced a surprisingly varied selection of versions of the Confession. These sources and what they can tell us about the theology and politics of the day are considered here for the first time in a scholarly study.Publisher PD
Open access self-archiving: An author study
No full textThis, our second author international, cross-disciplinary study on open access had 1296 respondents. Its focus was on self-archiving. Almost half (49%) of the respondent population have self-archived at least one article during the last three years. Use of institutional repositories for this purpose has doubled and usage has increased by almost 60% for subject-based repositories. Self-archiving activity is greatest amongst those who publish the largest number of papers. There is still a substantial proportion of authors unaware of the possibility of providing open access to their work by self-archiving. Of the authors who have not yet self-archived any articles, 71% remain unaware of the option. With 49% of the author population having self-archived in some way, this means that 36% of the total author population (71% of the remaining 51%), has not yet been appraised of this way of providing open access. Authors have frequently expressed reluctance to self-archive because of the perceived time required and possible technical difficulties in carrying out this activity, yet findings here show that only 20% of authors found some degree of difficulty with the first act of depositing an article in a repository, and that this dropped to 9% for subsequent deposits. Another author worry is about infringing agreed copyright agreements with publishers, yet only 10% of authors currently know of the SHERPA/RoMEO list of publisher permissions policies with respect to self-archiving, where clear guidance as to what a publisher permits is provided. Where it is not known if permission is required, however, authors are not seeking it and are self-archiving without it. Communicating their results to peers remains the primary reason for scholars publishing their work; in other words,
researchers publish to have an impact on their field. The vast majority of authors (81%) would willingly comply with a mandate from their employer or research funder to deposit copies of their articles in an institutional or subject-based repository. A further 13% would comply reluctantly; 5% would not comply with such a mandate
Author Correction: A super-massive Neptune-sized planet (Nature, (2023), 622, 7982, (255-260), 10.1038/s41586-023-06499-2)
No full textCorrection to: Nature Published online 30 August 2023 In the version of the article initially published, Ian Crossfield (Department of Physics and Astronomy, University of Kansas, Lawrence, KS, USA) was missing from the author list and is now included, while Fig. 2 has been updated with the correct density values of all the exoplanets. The changes are made in the HTML and PDF versions of the article
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