Census estimates of algal and epiphytic carbonate production highlight tropical seagrass meadows as sediment production hotspots

This is the author accepted manuscript. The final version is available from Frontiers Media via the DOI in this record.Tropical shelf, platform and reef-lagoon systems are dominated by calcium carbonate (CaCO3) sediments. However, data on habitat-specific CaCO3 sediment production rates by different sediment producing taxa are sparse, limiting understanding of where and in what form CaCO3 sediment is produced, and how overall sediment budgets are influenced by habitat type and scale. Using novel census methodologies, based primarily on measures of plant biovolumes and carbonate content, we assessed habitat-scale production by two ubiquitous biogenic CaCO3 sediment producers, calcareous green algae and seagrass epiphytes, across southern Eleuthera Bank, Bahamas (area ~140 km2). Data from species-specific plant disaggregation experiments and from X-ray diffraction (XRD) analysis of calcified plants also allowed us to resolve questions about the size fractions and mineralogies of the carbonates produced. Production rates varied significantly among habitats (range: 1.8–237.3 g CaCO3 m-2 yr-1), collectively totalling ~0.98 M kg annually across the study area. Outputs comprise similar amounts of aragonite and high Mg-calcite, with ~54% of the CaCO3 produced being contributed as mud-grade (<63 μm) sediment. Our analysis also reveals that habitat type and extent - especially of medium and high density seagrass beds - strongly influence the amounts and types of carbonate sediment generated. Dense seagrass beds were identified as the dominant per unit area production sites, contributing ~17% of total CaCO3 despite covering only 0.5% of the study area. These findings have direct relevance for quantifying present-day sediment budgets and for predicting changes in sediment generation at the system scale in responses to modified habitat extent and productivity.Natural Environment Research Council (NERC

Izolacija i sposobnost hvatanja slobodnih radikala cijanidin 3-O-glikozida iz plodova Ribes biebersteinii Berl.

The reversed-phase preparative high performance liquid chromatographic purification of the methanol extract of the fruits of Ribes biebersteinii Berl. (Grossulariaceae) afforded five cyanidin glycosides, 3-O-sambubiosyl-5-O-glucosyl cyanidin (1), cyanidin 3-O-sambubioside (2), cyanidin 3-O-glucoside (3), cyanidin 3-O-(2G-xylosyl)-rutinoside (4) and cyanidin 3-O-rutinoside (5). They showed considerable free-radical-scavenging properties in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay with the RC50 values of 9.29 × 106, 9.33 × 106, 8.31 × 106, 8.96 × 106 and 9.55 × 106 mol L1, respectively. The structures of these compounds were elucidated by various chemical hydrolyses and spectroscopic means. The total anthocyanin content was 1.9 g per 100 g dried fruits on cyanidin 3-glucoside basis.Pet cijanidin glikozida, 3-O-sambubiozil-5-O-glukozil cijanidin (1), cijanidin 3-O-sambubiozid (2), cijanidin 3-O-glukozid (3), cijanidin 3-O-(2G-ksilozil)-rutinozid (4) i cijanidin 3-O-rutinosid (5) izolirani su iz metanolnog ekstrakta plodova Ribes biebersteinii Berl. (Grossulariaceae) koristeći reverzno-faznu preparativnu tekućinsku kromatografiju visoke učinkovitosti. Cijanidin glikozidi pokazali su sposobnost hvatanja slobodnih radikala u pokusu s 2,2-difenil-1-pikrilhidrazilom (DPPH). Dobivene su sljedeće RC50 vrijednosti: 9,29 × 106, 9,33 × 106, 8,31 × 106, 8,96 × 106, odnosno 9,55 × 106 mol L1. Strukture glikozida određene su kemijskom hidrolizom i spektroskopijom masa. Ukupni sadržaj antocijanina bio je 1,9 g na 100 g suhih plodova preračunato na cijanidin 3-glukozid

Antibacterial, Anti-HIV-1 Protease and Cytotoxic Activities of Aqueous Ethanolic Extracts from Combretum Adenogonium Steud. Ex A. Rich (Combretaceae).

\ud \ud Records have shown that Combretum adenogonium Steud. Ex A. Rich (Combretaceae) is used in traditional medicine systems of several tribes in Tanzania. This study focused on the investigation of antibacterial activity, anti-HIV-1 protease activity, toxicity properties and classes of phytochemicals in extracts from C. adenogonium Steud. Ex A. Rich (Combretaceae) to evaluate potential of these extracts for development as herbal remedies. Dried plant material were ground to fine powder and extracted using 80% aqueous ethanol to afford root, leaf and stem bark extracts. The extracts were assayed for anti-HIV-1 protease activities, antibacterial activities using microdilution methods and cytotoxicity using brine shrimps lethality assay. Screening for major phytochemical classes was carried out using standard chemical tests. All extracts exhibited antibacterial activity to at least one of the test bacteria with MIC-values ranging from 0.31-5.0 mg/ml. Two extracts, namely, root and stem bark exhibited anti-HIV-1 PR activity with IC50 values of 24.7 and 26.5 μg/ml, respectively. Stem bark and leaf extracts showed mild toxicity with LC50 values of 65.768 μg/ml and 76.965 μg/ml, respectively, whereas roots were relatively non-toxic (LC50 = 110.042 μg/ml). Phytochemical screening of the extracts indicated presence of flavonoids, terpenoids, alkaloids, tannins, glycosides and saponins. These results provide promising baseline information for the potential development of C. adenogonium extracts in treatment of bacterial and HIV/AIDS-related opportunistic infections

Efficient orchestration of Node-RED IoT workflows using a vector symbolic architecture

Numerous workflow systems span multiple scientific domains and environments, and for the Internet of Things (IoT), Node-RED offers an attractive Web based user interface to execute IoT service-based workflows. However, like most workflow systems, it coordinates the workflow centrally, and cannot run within more transient environments where nodes are mobile. To address this gap, we show how Node-RED workflows can be migrated into a decentralized execution environment for operation on mobile ad-hoc networks, and we demonstrate this by converting a Node-RED based traffic congestion detection workflow to operate in a decentralized environment. The approach uses a Vector Symbolic Architecture (VSA) to dynamically convert Node-Red applications into a compact semantic vector representation that encodes the service interfaces and the workflow in which they are embedded. By extending existing services interfaces, with a simple cognitive layer that can interpret and exchange the vectors, we show how the required services can be dynamically discovered and interconnected into the required workflow in a completely decentralized manner. The resulting system provides a convenient environment where the Node-RED front-end graphical composition tool can be used to orchestrate decentralized workflows. In this paper, we further extend this work by introducing a new dynamic VSA vector compression scheme that compresses vectors for on-the-wire communication, thereby reducing communication bandwidth while maintaining the semantic information content. This algorithm utilizes the holographic properties of the symbolic vectors to perform compression taking into consideration the number of combined vectors along with similarity bounds that determine conflict with other encoded vectors used in the same context. The resulting savings make this approach extremely efficient for discovery in service-based decentralized workflows

Compact to extended Lyman-α\alpha emitters in MAGPI: strong blue peak emission at z≳3z\gtrsim3

We report the discovery of three double-peaked Lyman-$\alpha$ emitters (LAEs) exhibiting strong blue peak emission at 2.9 $\lesssim z \lesssim$ 4.8, in the VLT/MUSE data obtained as part of the Middle Ages Galaxy Properties with Integral Field Spectroscopy (MAGPI) survey. These strong blue peak systems provide a unique window into the scattering of Lyman-$\alpha$ photons by neutral hydrogen (HI), suggesting gas inflows along the line-of-sight and low HI column density. Two of them at $z=2.9$ and $z=3.6$ are spatially extended halos with their core regions clearly exhibiting stronger blue peak emissions than the red peak. However, spatial variations in the peak ratio and peak separation are evident over $25\times 26$ kpc ($z=2.9$) and $19\times28$ kpc ($z=3.6$) regions in these extended halos. Notably, these systems do not fall in the regime of Lyman-$\alpha$ blobs or nebulae. To the best of our knowledge, such a Lyman-$\alpha$ halo with a dominant blue core has not been observed previously. In contrast, the LAE at $z\sim4.8$ is a compact system spanning a $9\times9$ kpc region and stands as the highest-redshift strong blue peak emitter ever detected. The peak separation of the bright cores in these three systems ranges from $\Delta_{\mathrm{peak}}\sim370$ to $660$ km/s. The observed overall trend of decreasing peak separation with increasing radius is supposed to be controlled by HI column density and gas covering fraction. Based on various estimations, in contrast to the compact LAE, our halos are found to be good candidates for LyC leakers. These findings shed light on the complex interplay between Lyman-$\alpha$ emission, gas kinematics, and ionising radiation properties, offering valuable insights into the evolution and nature of high-redshift galaxies.Comment: 2 Figures, 1 Table, accepted for A&A Letter