Differences in Thermal Tolerance Between Two Thermally Isolated and Genetically Indistinct Populations of \u3ci\u3eParagnetina Media\u3c/i\u3e (Walker) (Plecoptera: Perlodidae)

The critical thermal maximum (CTM) of Paragnetina media (Walker) (Plecoptera: Perlodidae) was studied at two sites of the Big Sable River in northwestern Lower Michigan during summer 2013. The sites were separated by ~8 km and differed in temperature by ~1°C in the early spring to ~5°C in mid-summer. Individual P. media specimens from the warm site had consistently higher CTM when acclimated to the mean temperature of the two sites for 3 days prior to experimental trials during May, June, and July. When acclimated for an additional 3 days to a higher or lower temperature, this thermal disadvantage disappeared. Groups of individuals from both sites simultaneously acclimated to both site temperatures for 3 days exhibited similar CTMs, except that cold site specimens acclimated to the cold temperature had a lower CTM than the other treatments. Sequencing of the CO1 gene revealed that nearly 75% of specimens shared a single haplotype, which was found in both warm and cold site individuals. Our results suggest that both long term and short term thermal history can influence thermal tolerance within populations of the same species that do not appear genetically distinct

Go Vegan

La méthode de mesure, due à Vernotte, des caractéristiques thermophysiques d'une plaque d'un matériau donné par application d'un film chauffant sur une face de la plaque et enregistrement en fonction du temps de l'évolution des températures de la face opposée, et éventuellement de la face chauffée, a été souvent mise en application. On précise ici quelles conditions doivent être remplies et quelles sont les incidences de divers défauts éventuels du montage quand on applique la variante due à Krischer de cette méthode. Un dispositif expérimental très simple a permis de corroborer ces considérations théoriques

Differences in Thermal Tolerance Between Two Thermally Isolated and Genetically Indistinct Populations of \u3ci\u3eParagnetina Media\u3c/i\u3e (Walker) (Plecoptera: Perlodidae)

The critical thermal maximum (CTM) of Paragnetina media (Walker) (Plecoptera: Perlodidae) was studied at two sites of the Big Sable River in northwestern Lower Michigan during summer 2013. The sites were separated by ~8 km and differed in temperature by ~1°C in the early spring to ~5°C in mid-summer. Individual P. media specimens from the warm site had consistently higher CTM when acclimated to the mean temperature of the two sites for 3 days prior to experimental trials during May, June, and July. When acclimated for an additional 3 days to a higher or lower temperature, this thermal disadvantage disappeared. Groups of individuals from both sites simultaneously acclimated to both site temperatures for 3 days exhibited similar CTMs, except that cold site specimens acclimated to the cold temperature had a lower CTM than the other treatments. Sequencing of the CO1 gene revealed that nearly 75% of specimens shared a single haplotype, which was found in both warm and cold site individuals. Our results suggest that both long term and short term thermal history can influence thermal tolerance within populations of the same species that do not appear genetically distinct

A Review of Volatile Organic Compound Contamination in Post-Industrial Urban Centers: Reproductive Health Implications Using a Detroit Lens

Volatile organic compounds (VOCs) are a group of aromatic or chlorinated organic chemicals commonly found in manufactured products that have high vapor pressure, and thus vaporize readily at room temperature. While airshed VOCs are well studied and have provided insights into public health issues, we suggest that belowground VOCs and the related vapor intrusion process could be equally or even more relevant to public health. The persistence, movement, remediation, and human health implications of subsurface VOCs in urban landscapes remain relatively understudied despite evidence of widespread contamination. This review explores the state of the science of subsurface movement and remediation of VOCs through groundwater and soils, the linkages between these poorly understood contaminant exposure pathways and health outcomes based on research in various animal models, and describes the role of these contaminants in human health, focusing on birth outcomes, notably low birth weight and preterm birth. Finally, this review provides recommendations for future research to address knowledge gaps that are essential for not only tackling health disparities and environmental injustice in post-industrial cities, but also protecting and preserving critical freshwater resources

Impact of Blood Preservatives and Anticoagulants on Cannabinoid Quantitative Analysis

The expanded use of recreational and medicinal cannabis products, as well as the appearance of new cannabinoid derivatives, increases the importance of implementing pre-analytical (sample collection) protocols and the development of recommendations for cannabinoid testing in biological samples. The accurate quantification of cannabinoids in biological samples is critical for providing a correct result interpretation, especially if specific thresholds have been legally set, as in drugs and driving cases in certain states. Previous studies have mainly focused on the impact of time and temperature on the stability of delta-9-tetrahydrocannabinol (delta-9-THC) and metabolites in blood samples; however, the influence of the type of blood collection tube has been frequently overlooked, and no studies investigated the stability of delta-8-THC and metabolites in this type of samples. This study focused on the impact of different preservatives and anticoagulants in the analysis of delta-9-THC, delta-8-THC, cannabidiol (CBD), and their hydroxy (delta-9-THC-OH, delta-8-THC-OH, CBD-OH) and carboxy (delta-9-THC-COOH, delta-8-THC-COOH, CBD-COOH) metabolites in blood samples stored at room temperature (RT) and at 4℃ up to one month. The type of preservatives and/or anticoagulants investigated were: potassium oxalate-sodium fluoride, 3.2% sodium citrate, K2EDTA, and SST. All cannabinoids showed stability issues at room temperature, with citrate blood showing the highest losses and K2EDTA blood with the lowest losses. The most unstable compound was CBD-OH at both storage temperatures. Delta-8 and delta-9-cannabinoids showed similar stability behavior, with delta-8-THC-OH and delta-8-THC being slightly more stable than delta-9-THC-OH and delta-9-THC, respectively. Delta-8 and 9-THC-COOH were found to be the most stable analytes

The timing of sea-level high-stands during Marine Isotope Stages 7.5 and 9: Constraints from the uranium-series dating of fossil corals from Henderson Island

Direct dating of fossil coral reefs using the U-series chronometer provides an important independent test of the Milankovitch orbital forcing theory of climate change. However, well-dated fossil corals pre-dating the last interglacial period (\u3e130 thousand years ago; ka) are scarce due to, (1) a lack of sampling localities, (2) insufficient analytical precision in U-series dating methods, and (3) diagenesis which acts to violate the assumption of closed-system U-series isotopic decay in fossil corals. Here we present 50 new high-precision U-series age determinations for fossil corals from Henderson Island, an emergent coral atoll in the central South Pacific. U-series age determinations associated with the Marine Isotope Stage (MIS) 9 interglacial and MIS 7.5 interstadial periods are reported. The fossil corals show relatively little open-system U-series behaviour in comparison to other localities with fossil coral reefs formed prior to the last glacial cycle, however, open-system U-series behaviour is still evident in most of the dated corals. In particular, percent-level shifts in the [230Th/238U]act composition are observed, leading to conventional U-series ages that are significantly younger or older than the true sample age. This open-system U-series behaviour is not accounted for by any of the open-system U-series models, indicating that new models should be derived. The new U-series ages reported here support and extend earlier findings reported in Stirling et al. (2001), providing evidence of prolific coral reef development on Henderson Island at 320 ka, most likely correlated with MIS 9.3, and subsequent reef development at 307 ka during MIS 9.1, while relative sea-level was potentially 20 m lower than during MIS 9.3. The U-series ages for additional well-preserved fossil corals are suggestive of minor reef development on Henderson Island during MIS 7.5 (245–230 ka) at 240.3 ± 0.8 and 234.7 ± 1.3 ka. All U-series observations are consistent with the Milankovitch theory of climate change, in terms of the timing of onset and termination of the dated interglacial and interstadial periods. The best preserved samples also suggest that the oceanic 234U/238U during MIS 9 and MIS 7.5 was within five permil of the modern open ocean composition. [Retrieved from publisher\u27s website: http://www.sciencedirect.com/science/article/pii/S001670371000147X