613 research outputs found

    Lithostratigraphy, biostratigraphy, and stable-isotope stratigraphy of cores from ODP Leg 105 site surveys, Labrador Sea and Baffin Bay

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    Trigger weight (TWC) and piston (PC) cores obtained from surveys of the three sites drilled during Ocean Drilling Program (ODP) Leg 105 were studied in detail for benthic foraminiferal assemblages, total carbonate (all sites), planktonic foraminiferal abundances (Sites 645 and 647), and stable isotopes (Sites 646 and 647). These high-resolution data provide the link between modern environmental conditions represented by the sediment in the TWC and the uppermost cores of the ODP holes. This link provides essential control data for interpretating late Pleistocene paleoceanographic records from these core holes. At Site 645 in Baffin Bay, local correlation is difficult because the area is dominated by ice-rafted deposits and by debris flows and/or turbidite sedimentation. At the two Labrador Sea sites (646 and 647), the survey cores and uppermost ODP cores can be correlated. High-resolution data from the site survey cores also provide biostratigraphic data that refine the interpretations compiled from core-catcher samples at each ODP site

    A novel application of queueing theory on the Caulerpenyne secreted by invasive Caulerpa taxifolia (Vahl) C.Agardh (Ulvophyceae, Caulerpales): a preliminary study

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    Aquarium originated marine green alga Caulerpa taxifolia was introduced into the Mediterranean Sea accidentally in 1984. This invasion has been negatively affecting the sub-littoral ecosystem of the Mediterranean. One of the important reasons for its success in the Mediterranean is its secondary toxic metabolite called caulerpenyne (CPN). Furthermore, CPN has anti-proliferative and apoptotic activities, therefore, CPN can be considered as a potential native source in cancer therapy. For that reason, modeling this metabolite might be of importance. Increase and decrease of the CPN level before reaching the critical level can be expressed by means of a queueing system in which the number of ‘customers' increases and decreases. In fact, production of CPN shows fluctuations for many environmental reasons, which allow us to apply queueing theory. In the present study, the expected time to reach the maximum caulerpenyne level was analyzed and evaluated using queueing theory

    HESS Opinions: "Climate, hydrology, energy, water: recognizing uncertainty and seeking sustainability"

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    Since 1990 extensive funds have been spent on research in climate change. Although Earth Sciences, including climatology and hydrology, have benefited significantly, progress has proved incommensurate with the effort and funds, perhaps because these disciplines were perceived as “tools” subservient to the needs of the climate change enterprise rather than autonomous sciences. At the same time, research was misleadingly focused more on the “symptom”, i.e. the emission of greenhouse gases, than on the “illness”, i.e. the unsustainability of fossil fuel-based energy production. Unless energy saving and use of renewable resources become the norm, there is a real risk of severe socioeconomic crisis in the not-too-distant future. A framework for drastic paradigm change is needed, in which water plays a central role, due to its unique link to all forms of renewable energy, from production (hydro and wave power) to storage (for time-varying wind and solar sources), to biofuel production (irrigation). The extended role of water should be considered in parallel to its other uses, domestic, agricultural and industrial. Hydrology, the science of water on Earth, must move towards this new paradigm by radically rethinking its fundamentals, which are unjustifiably trapped in the 19thcentury myths of deterministic theories and the zeal to eliminate uncertainty. Guidance is offered by modern statistical and quantum physics, which reveal the intrinsic character of uncertainty/entropy in nature, thus advancing towards a new understanding and modelling of physical processes, which is central to the effective use of renewable energy and water resources

    Duckweed production on diluted chicken manure

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    The aim of this study was to test chicken manure as duckweed (Lemna minor) fertiliser. Duckweed was grown using three different concentrations (low, medium and high; dilution factors 1:16, 1:12 and 1:8, respectively) of previously solubilised chicken manure. Subsequently, duckweed was evaluated for its fresh and dry biomass production, protein content and protein production capacity. Ammonium-nitrogen (NH4-N) concentrations increased in all substrates during an experimental week, with the increase being steeper in the treatments with higher chicken manure concentrations. However, duckweed populations were unable to fully utilise all the provided nitrogen. As the concentration of chicken manure increased, growth and protein production decreased. Adding the highest concentration of chicken manure (1:8 dilution) led to nearly complete die-off of the duckweed population. The low concentrated (1:16 dilution) chicken manure fertilisation resulted in acceptable growth (1.85 g dry matter (DM) per m2 and day) and high crude protein content (42.8% DM). The medium concentration (1:12 dilution) of chicken manure still stimulated growth, although it was significantly lower compared to duckweed grown on the low concentrated poultry manure and declined towards the end of the experiment (0.88 g DM per m2 and day). The biomass from this treatment also contained slightly lower protein content (40.6% DM). Duckweed cultivated using low and medium chicken manure concentrations produced an average of 0.79 and 0.36 g protein per m2 and day, respectively. Although solubilised chicken manure can serve as a potential fertiliser for duckweed, balancing the amount of chicken manure necessary to obtain a target NH4-N concentration when compared to cow or pig slurries is challenging

    Development in Astronomy and Space Science in Africa

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    The development of astronomy and space science in Africa has grown significantly over the past few years. These advancements make the United Nations Sustainable Development Goals more achievable, and open up the possibility of new beneficial collaborations.Comment: Paper published in Nature Astronomy. Figures 1 and 2 are included in the published version, that can be seen at https://rdcu.be/2oE

    Impact of gaming disorder on first episode psychosis patients' evolution: Protocol for a multicentered prospective study.

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    The objective of this study is to underline the impact of Gaming Disorder on the clinical evolution of patients with First Episode Psychosis. The specific aims of the study are to determine the prevalence of gaming disorder among those patients and assess the consequences of gaming on their clinical trajectory. This is a prospective multicenter cohort study that will enrol 800 patients diagnosed with a first episode psychosis, with a follow-up period of up to 3 years. Using a systematic screening procedure for gaming disorder, the clinical staff will assess patients gaming habits at admission and every 6 months thereafter. Information from patients' medical records will also be extracted using the same timeframe. The patients' characteristics at admission and during follow-up will be presented in the form of descriptive statistics and compared between different subgroups of patients using uni- and multivariate logistic regression models. Repeated measures ANCOVA will also be performed to analyse the impact of gaming disorders on patients' clinical path as assessed by the Positive and Negative Syndrome Scale and the Clinical Global Impression scale, considering covariates such as psychiatric diagnosis, pharmacological treatment, age, sex/gender, and duration of untreated psychosis. These findings will guide the development of prevention, detection, and treatment strategies for the comorbidity between gaming disorder and first episode psychosis, ultimately improving the patients' recovery

    Effects of dietary Sanguisorba minor, Plantago lanceolata, and Lotus corniculatus on urinary N excretion of dairy cows

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    Mitigating urinary nitrogen (N) losses is an important target of sustainable cattle nutrition concepts. One option to achieve this may be dietary inclusion of tanniferous herbs. Aims. Aim of the study was to investigate herbs with different profiles of tannins for their efficiency to abate urinary N losses. Small burnet (Sanguisorba minor) with high concentrations of total tannins, plantain (Plantago lanceolata) with low concentrations and birdsfoot trefoil (Lotus corniculatus) with expectedly high concentrations of condensed tannins were included in the treatments. Methods. The test plants were mixed in dried form into a grass–maize-silage diet at 80 g/kg of dietary dry matter. They replaced dried perennial ryegrass (control). Twenty four multiparous dairy cows were randomly allocated to the four diets. Intake, eating time, rumination time, and milk yield were recorded individually, and representative samples of milk and excreta were collected and analysed six times within 14 days, following 10 days of adaptation. The diets with ryegrass, birdsfoot trefoil, plantain or burnet contained, per kilogram of dry matter, 0, 1.8, 1.2 and 1.9 g condensed tannins, 0.1, 1.9, 1.7 and 15.5 g total tannins, and 26.2, 28.5, 27.5 and 26.6 g N. Key results. Milk yield and composition were not affected by treatment, apart from a decline in milk protein content when feeding plantain. Milk urea concentration was reduced with burnet by more than 30%, compared with the control and plantain. Birdsfoot trefoil also reduced milk urea concentration, but to a lesser degree. Furthermore, the burnet treatment substantially shifted N excretion from urine to faeces (about 30% lower urine N losses). All treatments lowered the proportion of fine particles of <1.0 mm in faeces, what might be due to high fibre content of the control. Conclusions. At dietary proportion of 80 g/kg, burnet is a forage herb with potential to reduce ruminal ammonia generation as indicated by reduced urinary N and milk urea. Plantain and birdsfoot trefoil had no or negligible effects. Implications. The study indicated that small burnet could have potential as a feed additive for dairy cows in terms of N-use efficiency, lower emissionsto the environment, and reduced animal metabolic stress

    Structural and optical characteristics of erbium doped ternary TeO2-TiO2-Bi2O3 glasses

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    In this work we investigated both structural and optical characteristic of erbium doped ternary TeO2-TiO2-Bi2O3 tellurite oxide based glasses, synthesized via melt-quench method. The X-ray diffraction (XRD) and differential scanning calorimetry (DSC) confirmed its glassy nature and stability. Raman analysis revealed the presence of various coordination state TeO2 network consisting stretching/bending vibrations of Te-O bonds in the [TeO4] trigonal bi-pyramid units and fraction of [TeO3, TeO3+1] trigonal pyramids. From optical absorption measurement both optical band gap and Judd-Ofelt analysis (intensity parameters Ωt (t=2, 4, 6), transition probabilities, and radiative lifetimes of the Er3+ ions) have been performed for both host and doped glasses respectively. Photoluminescence studies for upconversion and near-infrared emissions analysis (under 980 nm excitation at room temperature. Both optical transition mechanism which involved nonradiative energy transfer between Er3+ ions through cross-relaxation and energy migration were also explained in detailed
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