Search for: All records

The Paleocene‐Eocene thermal maximum (PETM, 56 Ma) is an ancient global warming event closely coupled to the release of massive amounts of d13C‐depleted carbon into the ocean‐atmosphere system, making it an informative analogue for future climate change. However, uncertainty still exists regarding tropical sea‐surface temperatures (SSTs) in open ocean settings during the PETM. Here, we present the first paired d13C:Mg/Ca record derived in situ from relatively well‐preserved subdomains inside individual planktic foraminifer shells taken from a PETM record recovered in the central Pacific Ocean at Ocean Drilling Program Site 865. The d13C signature of each individual shell was used to confirm calcification during the PETM, thereby reducing the unwanted effects of sediment mixing that secondarily smooth paleoclimate signals constructed with fossil planktic foraminifer shells. This method of “isotopic screening” reveals that shells calcified during the PETM have elevated Mg/Ca ratios reflecting exceptionally warm tropical SSTs (∼33–34°C). The increase in Mg/Ca ratios suggests ∼6°C of warming, which is more congruent with SST estimates derived from organic biomarkers in PETM records at other tropical sites. These extremely warm SSTs exceed the maximum temperature tolerances of modern planktic foraminifers. Important corollaries to the findings of this study are (a) the global signature of PETM warmth was uniformly distributed across different latitudes, (b) our Mg/Ca‐based SST record may not capture peak PETM warming at tropical Site 865 due to the thermally‐induced ecological exclusion of planktic foraminifers, and (c) the record of such transitory ecological exclusion has been obfuscated by post‐depositional sediment mixing at Site 865. 

Abstract During a SARS-CoV-2 infection, macrophages recognize viral components resulting in cytokine production. While this response fuels virus elimination, overexpression of cytokines can lead to severe COVID-19. Previous studies suggest that the spike protein (S) of SARS-CoV-2 can elicit cytokine production via the transcription factor NF-κB and the toll-like receptors (TLRs). In this study, we found that: (i) S and the S2 subunit induceCXCL10, a chemokine implicated in severe COVID-19, gene expression by human macrophage cells (THP-1); (ii) a glycogen synthase kinase-3 inhibitor attenuates this induction; (iii) S and S2 do not activate NF-κB but do activate the transcription factor IRF; (iv) S and S2 do not require TLR2 to elicit CXCL10 production or activate IRF; and (v) S and S2 elicit CXCL10 production by peripheral blood mononuclear cells (PBMCs). We also discovered that the cellular response, or lack thereof, to S and S2 is a function of the recombinant S and S2 used. While such a finding raises the possibility of confounding LPS contamination, we offer evidence that potential contaminating LPS does not underly induced increases in CXCL10. Combined, these results provide insights into the complex immune response to SARS-CoV-2 and suggest possible therapeutic targets for severe COVID-19. 

Abstract Background Informal learning experiences in science, technology, engineering, and math (STEM) can enhance STEM learning that occurs in formal educational settings and curricula as well as generate enthusiasm for considering STEM careers. The aim of this systematic review is to focus on the experiences of neurodiverse students in informal STEM learning. Neurodiversity is a subgroup of neurodevelopmental conditions, such as autism, attention deficit disorder, dyslexia, dyspraxia, and other neurological conditions. The neurodiversity movement regards these conditions as natural forms of human variation, as opposed to dysfunction, and recognizes that neurodiverse individuals possess many strengths relevant to STEM fields. Methods The authors will systematically search electronic databases for relevant research and evaluation articles addressing informal STEM learning for K-12 children and youth with neurodiverse conditions. Seven databases and content-relevant websites (e.g., informalscience.org) will be searched using a predetermined search strategy and retrieved articles will be screened by two members of the research team. Data synthesis will include meta-synthesis techniques, depending on the designs of the studies. Discussion The synthesis of the findings resulting from various research and evaluation designs, across the K-12 age span, and across various informal STEM learning contexts, will lead to depth and breadth of understanding of ways to improve informal STEM learning programs for neurodiverse children and youth. The identification of informal STEM learning program components and contexts shown to yield positive results will provide specific recommendations for improving inclusiveness, accessibility, and STEM learning for neurodiverse children and youth. Trial registration The current study has been registered in PROSPERO. Registration number: CRD42021278618. 

Abstract An investigation of lake effect (LE) and the associated synoptic environment is presented for days when all five lakes in the Great Lakes (GL) region had LE bands [five-lake days (5LDs)]. The study utilized an expanded database of observed LE clouds over the GL during 25 cold seasons (October–March) from 1997/98 to 2021/22. LE bands occurred on 2870 days (64% of all cold-season days). Nearly a third of all LE bands occurred during 5LDs, although 5LDs consisted of just 17.1% of LE days. A majority of 5LDs (56.5%) had lake-to-lake (L2L) bands, and these days comprised 43.5% of all L2L occurrences. 5LDs occurred with a mean of 26.1 (SD = 6.2) days per cold season until 2008/09 and then decreased to a mean of 13.8 (SD = 5.5) days during subsequent cold seasons. January and February had the largest number of consecutive LE days in the GL with a mean of 5.7 and 5.4 days, respectively. As the number of consecutive LE days increases, both the number of 5LDs and the occurrence of consecutive 5LD increase. This translates to an increased potential of heavy snowfall impacts in multiple, localized areas of the GL for extended time periods. The mean composite synoptic pattern of 5LDs exhibited characteristics consistent with lake-aggregate disturbances and showed similarity to synoptic patterns favorable for LE over one or two of the GL found by previous studies. The results demonstrate that several additional areas of the GL are often experiencing LE bands when a localized area has active LE bands occurring. 

When an electromagnetically-nonlinear radar target is illuminated by a high-power stepped-frequency probe, a sequence of harmonics is unintentionally emitted by that target. Detection of the target is accomplished by receiving stimulated emissions somewhere in the sequence, while ranging is accomplished by processing amplitude and phase recorded at multiple harmonics across the sequence. The strength of the harmonics reflected from an electronic target depends greatly upon the orientation of that target (or equivalently, the orientation of the radar antennas). Data collected on handheld wireless devices reveals the harmonic angular-dependence of commercially-available electronics. Data collected on nonlinearly-terminated printed circuit boards implies the origin of this dependency. The results of this work suggest that electronic targets may be classified and ultimately identified by their unique harmonic-response-vs.-angle patterns. 

Biomolecular analyses are used to investigate the dynamics of cyanobacterial harmful algal blooms (cyanoHABs), with samples collected during monitoring often analyzed by qPCR and sometimes amplicon and metagenomic sequencing. However, cyanoHAB research and monitoring programs face operational constraints due to the reliance on human resources for sample collections. To address this impediment, a third-generation Environmental Sample Processor (3G ESP) integrated with a long-range autonomous underwater vehicle (LRAUV) was tested during seasonal blooms of Microcystis in western Lake Erie (WLE) in 2018 and 2019. The LRAUV-3G ESP successfully performed flexible, autonomous sampling across a wide range of cyanoHAB conditions, and results indicated equivalency between autonomous and manual methods. No significant differences were found between LRAUV-3G ESP and manual sample collection and handling methods in the 12 parameters tested. Analyzed parameters included concentrations of total cyanobacteria and microcystin toxin gene via qPCR; relative abundances of bacterial amplicon sequence variants (ASVs) from 16S rRNA gene amplicon sequencing; and community diversity measures from both 16S amplicon and metagenomic sequencing. The LRAUV-3G ESP provided additional sampling capacity and revealed differences between field seasons for bacterial taxa and concentrations of total cyanobacteria and microcystin toxin gene. Metagenomic analysis of multiple microcystin toxin genes corroborated the use of the mcyE gene as a proxy for the genomic potential of WLE cyanoHABs to produce microcystin. Overall, this study provides support for the use of autonomous ‘omics capability in WLE to help expand the spatial and temporal coverage of cyanoHAB monitoring operations.