20 research outputs found

    Nitrogen Balance in a Poorly Draining Intensively Cultivated Soil

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    The increasing use of nitrogen in fertilizers has not only increased the productivity of agricultural crops but also the concern for the effects of high N inputs on the natural environment. Economic, agronomic and environmental concerns have led to greater efforts towards more effective utilization of nitrogenous fertilizers, which can be achieved through a better quantitative understanding of the fate of nitrogen when applied to the soil. So Nitrogen balance was investigated in a poorly draining intensively cultivated soil. Nitrogen inputs and outputs, such as additions by precipitation (Natm), irrigation water (Nirr), commercial fertilizers (Nfert), mineralization (Nmin), denitrification (Ndenitr), volatilization (Ngas), capillary rise (Ncap), uptake (Nupt), residual (Nres) and leaching (Nleac) were studied and quantified during a period of 72 weeks for two growing crops (maize and wheat). Nitrogen excess or deficit at time ‘t’ (Nt) was calculated from the following balance equation: Nt = Nres + Natm + Nirr + Nmin + Nfert + Ncap − Nupt − Ndenitr – Ngas − Nleac. Existing models were used after proper adjustments to calculate these fluxes. Only a single model, based on soil temperature at 60 cm and NO3--N concentration in ground water was developed for the estimation of denitrification at the ground water boundary. The calculated values satisfactorily matched the respective experimental data. The results shown that the greater part of the applied nitrogen fertilizer was lost to ground water during the winter causing considerable environmental concern. For sustainable land use, inputs and outputs of nutrients must be balanced in order to avoid negative impacts on the environment, especially in intensively exploited agricultural ecosystems

    Cadmium Effects on Hyssop (Hyssopus officinalis L.) Morphology and Cd Uptake in Relation to Substrate Acidity/Alkalinity

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    Hyssop (Hyssopus officinalis), is a herb with a wide range of use in food preparation and herbal medicine. It is a perennial shrub through which pollutants such as Cd may enter the human food chain Therefore, the aim of this research was to examine the extent to which Cd added to the growth substrate is accumulated by hyssop plants and whether Cd affects the plant’s morphology. Hyssop plants were grown in pots containing a uniform mixture of either moderately acidic or slightly alkaline substrate consisting of peat and perlite (1:1 v/v) to which Cd (CdSO4*8/3H2O) was added (0-control, 1, 2 and 5 mg Cd L-1) during the course of growth. No symptoms of toxicity or nutrient deficiency as well as no differences in plant height were attributed to Cd application irrespective of the growth stage or substrate. Cadmium uptake by aerial organs (shoots) and underground organs (roots) of hyssop increased with Cd application and was higher in the moderately acidic than in the slightly alkaline soil environment. Hyssop is a Cd accumulator and accumulation occurred mainly in the roots in the acidic substrate. Measurement of extractable Cd by diethylene triamine penta acetic acid – triethanol amine (DTPA-TEA) could be used to predict Cd uptake by hyssop plants

    Effects of Cadmium (Cd) on Dry Matter and on Cd Concentration in Leaves and Roots of Purple Coneflower (Echinacea purpurea L.)

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    The aim of this research was to examine the effect of Cd on leaves dry matter (LDM), root dry matter (RDM) and on Cd concentration in leaves (Cd-leaves) and roots (Cd-roots) of purple coneflower (E. purpurea) grown in an acid and in a neutral substrate. A completely randomized block design with four treatments (0-control, 1, 2, and 5 mg Cd L-1) and six replications for each treatment and each substrate (acid, neutral) was conducted in pot experiments. Cd concentration in leaves grown in acid substrate as well as in roots of plants grown in neutral substrate increased at Cd rates greater than 2 mg Cd L-1. Cd concentration in roots of the plants grown in neutral substrate raised with increasing doses of Cd. In general Cd concentration in the roots and leaves of purple coneflower grown either in acid or in neutral substrate was affected by Cd applications

    Response of St John’s wort (Hypericum empetrifolium) plants to cadmium (Cd) treatment in relation to substrate acidity/alkalinity

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    The effect of cadmium (Cd) on growth and Cd accumulation in shoots and roots St John’s wort (Hypericum empetrifolium) was studied over three months in a greenhouse. Plants were cultivated in pots containing a uniform mixture of either acid or alkaline substrate consisting of peat and perlite (1:1 v/v). The pots were arranged in a completely randomized block design within two groups (acid substrate and alkaline substrate) with four Cd treatments (0-control, 1, 2, and 5 mg Cd L-1) and six replicates per treatment. Cadmium was applied as CdSO4*8/3H2O. The total amount of Cd applied per pot was 260 ml, corresponding to 0.26, 0.52, and 1.3 mg Cd per pot for doses 1, 2, and 5 mg L-1, respectively. No visual symptoms of toxicity or nutrient deficiency, as well as no differences in plant height were observed in response to Cd application, irrespective of the growth stage or substrate. There were also no differences in height development rate between the plants grown in an acidic or alkaline substrate. Cd accumulation in shoots and roots increased with increasing concentrations of applied Cd and was higher in the acidic substrate. Thus, St John’s wort plant is a Cd accumulator, especially in an acidic environment, and this in combination with its high tolerance to Cd, makes it a suitable species to remove Cd from cadmium-contaminated sites. However, for its use in the preparation of medical products, St John’s wort must be grown in a Cd-free soil so as not to pose a risk to human health. Cd extraction by (DTPA-TEA) can be employed to predict Cd accumulation in this plant

    Cadmium effects on valerian (Valeriana officinalis L.) morphology and Cd uptake in relation to substrate acidity/alkalinity

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    Experiments were conducted on valerian (Valeriana officinalis L.) grown under glasshouse conditions to evaluate the effect of Cadmium (Cd) on plant morphological characteristics and Cd uptake. Valerian plants were grown in pots containing a uniform mixture of either moderately acidic or slightly alkaline substrate consisting of peat and perlite (1:1 v/v) over two periods. Pots were arranged in a completely randomized block design within two groups (moderately acid substrate and slightly alkaline substrate) with four Cd treatments (0, 1, 2 and 5 mg Cd L-1) and six replications per treatment. Cadmium was applied as CdSO4*8/3H2O. No visual symptoms of toxicity or nutrient deficiency were attributed to Cd application irrespective of the growth stage or substrate in either experimental period. Cadmium did not affect the dry mass of shoots or roots. Cd concentration in both shoots and roots increased with increasing Cd application, indicating valerian to be a Cd accumulator with accumulation occurring mainly in the roots both in moderately acidic or slightly alkaline substrates. The amount of Cd extracted by Diethylene triamine penta acetic acid-triethanol amine (DTPA-TEA) increased with increasing Cd doses and significantly correlates with the Cd concentrations within the shoots and roots indicating that this extractant could be used to predict Cd concentrations within the plant parts

    Effects of Vanadium and Nickel on Morphological Characteristics and on Vanadium and Nickel Uptake by Shoots of Mojito (Mentha × villosa) and Lavender (Lavandula anqustifolia)

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    Vanadium and Nickel may enter the human food chain through medicinal and culinary plants which in great doses are toxic to human, so it is important to determine their potential toxicity and health risk. Therefore, the objective of this work was to study the effects of Vanadium and Nickel on morphological characteristics and on Vanadium and Nickel uptake by shoots of mojito (Mentha × vilosa) and lavender (Lavandula anqustifolia). A completely randomized block design with five Vanadium treatments (0, 5, 10, 20, 40 mg V L-1) and five replications per treatment and another one with five Nickel treatments (0, 5, 10, 20 and 40 mg Ni L-1) and five replications per treatment for mojito and lavender were conducted in pots. No visible toxic or inhibitory symptoms were observed on the plants due to the increasing amounts of Vanadium or Nickel. Shoot dry matter and root dry matter of mojito and lavender decreased with increasing Vanadium rates. Vanadium uptake by shoots of mojito and lavender increased linearly with increasing Vanadium rates. Nickel uptake by shoots of lavender increased linearly with increasing rates of Nickel. Mojito is a Nickel accumulator

    Nickel (Ni) Effects on Shoots and Roots Dry Matter and on Ni Concentration in Shoots of Mojito (Mentha × villosa) and Lavender (Lavandula angustifolia)

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    Nickel is an essential trace element for plants, but excessive Ni levels in the soil can result in toxicity to plants. The aim of this research was to examine the effect of Ni on shoots dry matter (SDM), roots dry matter (RDM) and on Ni concentrations in SDM (Ni-SDM) of mojito and lavender plants. A completely randomized block design with five treatments (0, 5, 10, 20 and 40 mg Ni L-1) and five replications for each treatment and plant species was conducted in pot experiments. Nickel was applied to the pot medium as NiCl26H2O. No visible toxic or inhibitory symptoms were observed on the plants due to the increasing rates of Ni applications. The SDM and RDM were not affected by Ni in the studied plants. Ni-SDM of mojito and lavender raised with increasing rates of Ni above 20 and 10 mg Ni L-1, respectively

    Federated learning enables big data for rare cancer boundary detection.

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    Although machine learning (ML) has shown promise across disciplines, out-of-sample generalizability is concerning. This is currently addressed by sharing multi-site data, but such centralization is challenging/infeasible to scale due to various limitations. Federated ML (FL) provides an alternative paradigm for accurate and generalizable ML, by only sharing numerical model updates. Here we present the largest FL study to-date, involving data from 71 sites across 6 continents, to generate an automatic tumor boundary detector for the rare disease of glioblastoma, reporting the largest such dataset in the literature (n = 6, 314). We demonstrate a 33% delineation improvement for the surgically targetable tumor, and 23% for the complete tumor extent, over a publicly trained model. We anticipate our study to: 1) enable more healthcare studies informed by large diverse data, ensuring meaningful results for rare diseases and underrepresented populations, 2) facilitate further analyses for glioblastoma by releasing our consensus model, and 3) demonstrate the FL effectiveness at such scale and task-complexity as a paradigm shift for multi-site collaborations, alleviating the need for data-sharing

    Author Correction: Federated learning enables big data for rare cancer boundary detection.

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    10.1038/s41467-023-36188-7NATURE COMMUNICATIONS14

    Federated Learning Enables Big Data for Rare Cancer Boundary Detection

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    Although machine learning (ML) has shown promise across disciplines, out-of-sample generalizability is concerning. This is currently addressed by sharing multi-site data, but such centralization is challenging/infeasible to scale due to various limitations. Federated ML (FL) provides an alternative paradigm for accurate and generalizable ML, by only sharing numerical model updates. Here we present the largest FL study to-date, involving data from 71 sites across 6 continents, to generate an automatic tumor boundary detector for the rare disease of glioblastoma, reporting the largest such dataset in the literature (n = 6, 314). We demonstrate a 33% delineation improvement for the surgically targetable tumor, and 23% for the complete tumor extent, over a publicly trained model. We anticipate our study to: 1) enable more healthcare studies informed by large diverse data, ensuring meaningful results for rare diseases and underrepresented populations, 2) facilitate further analyses for glioblastoma by releasing our consensus model, and 3) demonstrate the FL effectiveness at such scale and task-complexity as a paradigm shift for multi-site collaborations, alleviating the need for data-sharing
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