What are the different styles of calcite precipitation within a hyperalkaline leachate? A sedimentological Anthropocene case study

This study aims to compare the fabrics of anthropogenic carbonates downstream of lime and steel disposal sites with models of carbonate precipitation from natural systems to elucidate potential drivers, precipitation mechanisms, morphological similarities, predictability in 3D facies distributions and depositional models of these systems. For this purpose, a combination of sedimentological, mineralogical and geochemical approaches is conducted including the analysis of microfacies (petrographic microscope and electron microscopy), X-ray diffraction and hydrochemistry. The data show that both anthropogenic and natural systems exhibit clear proximal, middle and distal zones of carbonate precipitation. The main macroscopic differences are the dominance of swamp environments in the proximal zone and the prevalence of tufa-like barrage-and-pool sequences in the middle and distal zones. Microfabrics in anthropogenic sites are comparable to travertines but lack the sub-surface facies and at extreme pH exhibit sparry crusts without clear equivalents in travertines. This sedimentology of anthropogenic carbonates shows that calcite mineral formation is complex and not homogeneous or purely driven by thermodynamic processes. Considering the sedimentology of these human-induced systems will help us understand precipitation mechanisms which will aid both efforts to utilise anthropogenic alkaline wastes for carbon capture and manage their environmental impacts

Seasonal rather than spatial variability drives planktonic and benthic bacterial diversity in a microtidal lagoon and the adjacent open sea

Coastal lagoons are highly productive ecosystems, which are experiencing a variety of human disturbances at increasing frequency. Bacteria are key ecological players within lagoons, yet little is known about the magnitude, patterns and drivers of diversity in these transitional environments. We carried out a seasonal study in the Venice Lagoon (Italy) and the adjacent sea, to simultaneously explore diversity patterns in different domains (pelagic, benthic) and their spatio-temporal variability, and test the role of environmental gradients in structuring assemblages. Community composition differed between lagoon and open sea, and between domains. The dominant phyla varied temporally, with varying trends for the two domains, suggesting different environmental constraints on the assemblages. The percentage of freshwater taxa within the lagoon increased during higher river run-off, pointing at the lagoon as a dynamic mosaic of microbial taxa that generate the metacommunity across the whole hydrological continuum. Seasonality was more important than spatial variability in shaping assemblages. Network analyses indicated more interactions between several genera and environmental variables in the open sea than the lagoon. Our study provides evidences for a temporally dynamic nature of bacterial assemblages in lagoons and suggests that an interplay of seasonally influenced environmental drivers shape assemblages in these vulnerable ecosystems

Biofilm production and antibiotic resistance of human and veterinary Staphylococcus strains.

Staphylococcus spp. is widely distributed in medical and veterinary pathology and represents one of the most important causes of infection. Many strains are antibiotic-resistant even for the presence of an eso-polysaccharide matrix. The aim of this work was to individuate, among 396 different Staphylococci of human and animal origin, the slime producing strains and to correlate the presence of biofilm to the resistance to eight antibiotics. A total of 185 coagulase negative staphylococci (CNS) and 211 S. aureus isolated from different sources and identified with Sceptor System, were tested for antibiotic susceptibility (Kirby Bauer method) and for slime production (Polystyrene plates – stained with Alcian blue – Spectrophotometric reading at 450 nm). The strains were classified as weak, strong and no slime-producing on the basis of OD results. The results were submitted to statistical analysis using Student’s t-test and chi-square tests. Evaluating the differences of slime production among medical and veterinary strains, we found different statistical frequencies (P > 0.001). No statistical differences wereobtained between S. aureus and the other CNS. Instead, the statistical analysis on S. epidermidis vs. the other staphylococci has shown no statistical differences among average values using Student’s ttest (P < 0.052) and significant frequency differences using chi square tests (P < 0.02). Finally in the CNS, between S. epidermidis and the other strains, no statistical differences were found. The relation between slime production and the origin of strains was evaluated and no correlation was found. About the correlation between antibiotic-resistance and slime production a resistance increment of about 30% was obtained in strongly slime producing strains. Staphylococcus spp. is often involved in nosocomial infections as complication of post-surgery wounds, catheters and orthopaedic devices. The presence of antibiotic-resistant strains interferes in the therapy successes and seems to be strictly related to biofilm production beyond that genetically acquired. Human and veterinary strains have shown a similar behaviour towards biofilm production and antibiotic-resistance. The results confirm that S. epidermidis is one of the most slime-producer and introduce S. aureus as a new high slime-producer

Brief communication "An extreme meteorological event at the ISMAR oceanographic tower"

We report the evidence of a remarkable meteorological event in the Northern Adriatic Sea. Following the irruption of cold northerly air into the previously hot and humid eastern part of the Po valley, a strong instability developed with violent thunderstorms. At the ISMAR oceanographic tower, 15 km off the coast of the Venice lagoon, although no one was on board, the records of 6 July 2008 from the various instruments coherently show the presence of an extreme and short-lived event that we associate either to a water spout or, more likely, to the strong downdraft of a mesoscale convective syste

What Causes Carbonates to Form “Shrubby” Morphologies? An Anthropocene Limestone Case Study

The South Atlantic Aptian “Pre-Salt” shrubby carbonate successions offshore Brazil and Angola are of major interest due to their potential hydrocarbon accumulations. Although the general sedimentology of these deposits is widely recognized to be within saline, alkaline lakes in rift volcanic settings, the specific genesis of shrubby carbonate morphologies remains unclear. This study reports the first petrographically comparable shrubby carbonates amongst other carbonate microfacies from an Anthropocene limestone formed under hyperalkaline (pH 9–12) and hypersaline (conductivity 425–3200 μS) conditions at ambient temperature (12.5–13°C) (Consett, United Kingdom). This discovery allows us to capitalize on exceptional long-term hydrochemical monitoring efforts from the site, demonstrating that shrubby carbonates occur uniquely within the waters richest in calcium (∼240 mg/L) and with highest pH (∼12) and consequently with very high levels of supersaturation. However, the physical distribution of shrubs is more comparable with estimated local kinetic precipitation rate than it is to thermodynamic saturation, indicating that the fundamental control on shrub formation arises from crystal surface processes. The shrubby carbonate we report grows in the presence of significant diatomaceous and cyanobacterial biofilms, despite the highly alkaline conditions. These biofilms are lost from the deposited material early due to the high solubility of organic and silica within hyperalkaline settings, and this loss contributes to very high intercrystalline porosity. Despite the presence of these microbes, few if any of the fabrics we report would be considered as “boundstones” despite it being clear that most fabrics are being deposited in the presence of abundant extra-cellular polymeric substances. We are aware of no previous petrographic work on anthropogenic carbonates of this type, and recommend further investigation to capitalize on what can be learned from these “accidental laboratories.”

In−situ monitoring Poly(3-hexylthiophene) nanowire formation and shape evolution in solution via small angle neutron scattering

The crystallization of poly(3-hexylthiophene) (P3HT) to form nanowires has attracted considerable interest because this process significantly increases the hole mobility when compared to amorphous P3HT, leading to improved performance in photovoltaic and other organic electronic devices. However, full characterization of the crystallization self-assembly of the polymer chains in solution has not been achieved yet, due to limited use of not destructive techniques. Here, we investigate the ageing-driven formation and evolution of regioregular (rr) P3HT nanostructures in chlorobenzene solution using small angle neutron scattering (SANS) and UV–Vis spectroscopy. We have monitored how the shape of the rr-P3HT aggregates evolves. The initial states for rr-P3HT chains are the random coils, which straighten to form rods. These subsequently π - π stack to form 2D lamellae, which further stack to create nanowires. The formation of nanowires is promoted both by the length of ageing and by low temperatures (). Temperatures above reverse the formation of nanowires. Additionally, atomic force microscopy (AFM) and grazing incidence wide angle x-ray scattering (GIWAXS) reveal that the nanowires can be successfully aligned during deposition by off-axis spin coating. Finally, the anisotropic conductivity of the aligned rr-P3HT nanowire films is reported. This is significant for applications such as gas sensing or organic thin film transistors, where increased conductivity and controlled nanostructure are desirable

Long Term Ecological Research (LTER) in the Marine Coastal Environment: Basic Concepts and Keystones from the Plankton Communities.

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Post-sigh sleep apneas in mice: Systematic review and data-driven definition

Sleep apneas can be categorized as post-sigh (prevailing in non-rapid eye movement sleep) or spontaneous (prevailing in rapid eye movement sleep) according to whether or not they are preceded by an augmented breath (sigh). Notably, the occurrence of these apnea subtypes changes differently in hypoxic/hypercapnic environments and in some genetic diseases, highlighting the importance of an objective discrimination. We aim to: (a) systematically review the literature comparing the criteria used in categorizing mouse sleep apneas; and (b) provide data-driven criteria for this categorization, with the final goal of reducing experimental variability in future studies. Twenty-two wild-type mice, instrumented with electroencephalographic/electromyographic electrodes, were placed inside a whole-body plethysmographic chamber to quantify sleep apneas and sighs. Wake\u2013sleep states were scored on 4-s epochs based on electroencephalographic/electromyographic signals. Literature revision showed that highly different criteria were used for post-sigh apnea definition, the intervals for apnea occurrence after sigh ranging from 1 breath up to 20 s. In our data, the apnea occurrence rate during non-rapid eye movement sleep was significantly higher than that calculated before the sigh only in the 1st and 2nd 4-s epochs following a sigh. These data suggest that, in mice, apneas should be categorized as post-sigh only if they start within 8 s from a sigh; the choice of shorter or longer time windows might underestimate or slightly overestimate their occurrence rate, respectively

Dinoflagellate cysts production in the north-western Adriatic Sea

A sediment trap study was conducted in the Gulf of Venice, north-western Adriatic Sea, from April to December 2005 to assess relationships between planktonic dinoflagellates and cyst production. Every month, CTD profiles and discrete samplings for phytoplankton, nutrients and particulate matter were conducted. Cyst fluxes spanned from 90 to 127,600 cysts m-2 d-1 and major peaks were due to a small cyst attributed to cf. Biecheleria and to calcareous cysts of Scrippsiella trochoidea. A good correspondence between cyst fluxes in sediment traps and the presence of the corresponding vegetative cells in the water column was detected for Lingulodinium polyedrum, and species of the genera Spiniferites,Gonyaulax and Protoperidinium. A PCR method applied to surface sediment samples allowed the identification of a number of potentially harmful dinoflagellate cysts (Alexandrium minutum, A. tamutum, A. taylorii, Lingulodinium polyedrum and Protoceratium reticulatum)

Neural control of fasting-induced torpor in mice

Torpor is a peculiar mammalian behaviour, characterized by the active reduction of metabolic rate, followed by a drop in body temperature. To enter torpor, the activation of all thermogenic organs that could potentially defend body temperature must be prevented. Most of these organs, such as the brown adipose tissue, are controlled by the key thermoregulatory region of the Raphe Pallidus (RPa). Currently, it is not known which brain areas mediate the entrance into torpor. To identify these areas, the expression of the early gene c-Fos at torpor onset was assessed in different brain regions in mice injected with a retrograde tracer (Cholera Toxin subunit b, CTb) into the RPa region. The results show a network of hypothalamic neurons that are specifically activated at torpor onset and a direct torpor-specific projection from the Dorsomedial Hypothalamus to the RPa that could putatively mediate the suppression of thermogenesis during torpor