50 research outputs found
Cold spells in the Nordic Seas during the early Eocene Greenhouse
Abstract The early Eocene (c. 56 - 48 million years ago) experienced some of the highest global temperatures in Earth’s history since the Mesozoic, with no polar ice. Reports of contradictory ice-rafted erratics and cold water glendonites in the higher latitudes have been largely dismissed due to ambiguity of the significance of these purported cold-climate indicators. Here we apply clumped isotope paleothermometry to a traditionally qualitative abiotic proxy, glendonite calcite, to generate quantitative temperature estimates for northern mid-latitude bottom waters. Our data show that the glendonites of the Danish Basin formed in waters below 5 °C, at water depths of <300 m. Such near-freezing temperatures have not previously been reconstructed from proxy data for anywhere on the early Eocene Earth, and these data therefore suggest that regionalised cool episodes punctuated the background warmth of the early Eocene, likely linked to eruptive phases of the North Atlantic Igneous Province.</jats:p
Spatiotemporal clustering, climate periodicity, and social-ecological risk factors for dengue during an outbreak in Machala, Ecuador, in 2010
Active Dilation of Penetrating Arterioles Restores Red Blood Cell Flux to Penumbral Neocortex after Focal Stroke
Altmetrics of South African Journals: Implications for Scholarly Impact of South African Research
Due to copyright restrictions the full-text of this article could not be attached to this record. Please follow the doi link at the top of the page to access the article on the publisher's website.The purpose of the study was to investigate and compare the social media
(SM) impact of 273 South Africa Post-Secondary Education accredited journals,
which are recognised by the Department of Higher Education and Training of South
Africa for purposes of financial support. We used multiple sources to extract data
for the study, namely, Altmetric.com, Google Scholar (GS), Scopus (through
SCImago) and the Thomson Reuters (TR) Journal Citation Reports (JCR). Data was
analysed to determine South African journals’ presence in and impact on SM as well
as to contrast SM visibility and impact with the citation impact in GS, JCR and
Scopus. The Spearman correlation test was performed to compare the impact of the
journals on SM and other sources. The results reveal that 2923 articles published in
122 of the 273 South African (SA) journals have received at least one mention in
SM; the most commonly used SM platforms were Twitter and Facebook; the
journals indexed in the TR’s citation indexes and Scopus performed much better, in
terms of their average altmetrics, than non-TR and non-Scopus indexed journals;
and there were weak to moderate relationships among different types of altmetrics
and citation-based measures, thereby implying different kinds of journal impacts on
SM when compared to the scholarly impact reflected in citation databases. In
conclusion, South African journals’ impact on SM, just as is the case with countries
with similar economies, is minimal but has shown signs of growth.Information Scienc
Post-embriononic development of Chrysomya putoria(Diptera: Calliphoridae) on a diet containing ampicillin in different concentrations
Here we evaluate the effects of different concentrations of the antibiotic ampicillin on the growth and development of Chrysomya putoria. Third-generation, first instar larvae (L1) reared on 60 grams of homogenate+agar 65% were treated with ampicillin sodium. The experiment consisted of four replicates (40 larvae/replicate) of each antibiotic concentration tested (T1: 466µg/mL ; T2: 81.33 mg/mL and T3: 166.66mg/mL) and a T4: control. The body mass of the mature larvae, after they abandoned the diet, were recorded in batches of five. The variation between the mean body mass of larvae and the duration of larval and pupal stages, and overall duration of the development, viability and normal rates were analyzed by ANOVA. There were no significant differences between the four treatments in the following parameters: body mass of larvae that discontinued the diet as well as the duration of larval, pupal, and total development. The sex ratios found in the four treatments did not differ from those expected. Normality rates were 100% for all treatments. There were no significant differences between treatments for larval and overall viability, but pupal viability differed significantly between T1 and the control, T1 and T2, and between the control and T3. The antibiotic did not appear to significantly alter the development of C. putoria
