Trace Elements in Magnetite from the Pagoni Rachi Porphyry Prospect, NE Greece: Implications for Ore Genesis and Exploration

Magnetite is a common accessory phase in various types of ore deposits. Its trace element content has proven to have critical implications regarding petrogenesis and as guides in the exploration for ore deposits in general. In this study we use LA-ICP-MS (laser ablation-inductively coupled plasma-mass spectrometry) analyses of trace elements to chemically characterize magnetite from the Pagoni Rachi Cu–Mo–Re–Au porphyry-style prospect, Thrace, northern Greece. Igneous magnetite mostly occurs as euhedral grains, which are commonly replaced by hematite in fresh to propylitic-altered granodiorite porphyry, whereas, hydrothermal magnetite forms narrow veinlets or is disseminated in sodic/potassic-calcic altered (albite + K-feldspar + actinolite + biotite + chlorite) granodiorite porphyry. Magnetite is commonly associated with chalcopyrite and pyrite and locally exhibits martitization. Laser ablation ICP-MS analyses of hydrothermal magnetite yielded elevated concentrations in several trace elements (e.g., V, Pb, W, Mo, Ta, Zn, Cu, and Nb) whereas Ti, Cr, Ni, and Sn display higher concentration in its magmatic counterpart. A noteworthy enrichment in Mo, Pb, and Zn is an unusual feature of hydrothermal magnetite from Pagoni Rachi. High Si, Al, and Ca values in a few analyses of hydrothermal magnetite imply the presence of submicroscopic or nano-inclusions (e.g., chlorite, and titanite). The trace element patterns of the hydrothermal magnetite and especially the decrease in its Ti content reflect an evolution from the magmatic towards the hydrothermal conditions under decreasing temperatures, which is consistent with findings from analogous porphyry-style deposits elsewhere

Methane Emissions from Ruminants on Integrated Crop-Livestock Systems

Ruminant livestock produce ~80 million tonnes of methane (CH4) annually, accounting for ~33% of global anthropogenic emissions of CH4 (Beauchemin et al. 2008). CH4 is a powerful greenhouse gas, with global warming potential of 25 (Eckard et al. 2010), and represents a significant loss of dietary energy (2 to 12% of gross energy of feeds; Patra 2012) in the ruminant production system. Despite greenhouse gas (GHG) emissions have become an increasingly important topic worldwide, there is still a high variability around the estimated values of these emissions, mainly about emissions attributable to livestock (range from 8 to 51%; Herrero et al. 2011). This variability creates confusion among researchers, policy makers and the public, particularly in tropical/sub-tropical regions due substantial uncertainties. Therefore, using rigorous and internationally accepted protocols, a Brazilian national project was established in order to contribute for the estimates of GHG emissions attributable to livestock in Brazilian ruminant production systems. Moreover, enteric CH4 emissions are a major challenge for research, in order to develop technologies and strategies for sustainable ruminant production systems in the future (Eckard et al. 2010). In recent years, integrated crop-livestock systems (ICLS) have gained interest due to, for example, the abatement of methane from livestock production: directly through a reduction in CH4 per unit of animal products resulting from the increase on feed quality and animal welfare (i.e. improved environmental temperature for ICLS with trees), and indirectly through reduction of area submitted to land use changes (i.e. leading to a loss of soil C stocks). This paper deals with the preliminary results from CH4 emissions by beef heifers grazing in two ICLS (i.e. production system that integrates corn or soybeans crops, during the warm season, and cattle grazing on a cool season pasture, on the same area and in the same cropping year, with or without trees), how these findings contributes to determine the soil C balance and mitigation measures

Stability of functionalized platform molecules on Au(111)

Trioxatriangulenium (TOTA) platform molecules were functionalized with methyl, ethyl, ethynyl, propynyl, and hydrogen and sublimated onto Au(111) surfaces. Low-temperature scanning tunneling microscopy data reveal that >99% of ethyl-TOTA and methyl-TOTA remain intact, whereas 60% of H-TOTA and >99% of propynyl-TOTA and ethynyl-TOTA decompose. The observed tendency toward fragmentation on Au(111) is opposite to the sequence of gas-phase stabilities of the molecules. Although Au(111) is the noblest of all metal surfaces, the binding energies of the decomposition products to Au(111) destabilize the functionalized platforms by 2 to 3.9 eV (190–370 kJ/mol) and even render some of them unstable as revealed by density functional theory calculations. Van der Waals forces are important, as they drive the adsorption of the platform molecules

Ambition meets reality:Achieving GHG emission reduction targets in the livestock sector of Latin America

Livestock production is a very relevant source of income and agricultural greenhouse gas (GHG) emissions in Colombia, Brazil, Argentina, Costa Rica, Uruguay, Mexico, and Peru. Several management and technological options with enteric methane mitigation potential have been evaluated and their scaling is anticipated to contribute toward achieving GHG emission reduction targets in the framework of the Paris Agreement. Yet, widespread adoption of promising mitigation options remains limited, raising questions as to whether envisaged emission reduction targets are achievable. Using findings from local studies, we explore the mitigation potentials of technologies and management practices currently proposed to mitigate enteric methane emissions from cattle production systems in the higher emitting countries of Latin America. We then discuss barriers for adopting innovations that significantly reduce cattle-based enteric methane emissions and the major shifts in policy and practice that are needed to raise national ambitions in the high emitting countries. Using the latest science and current thinking, we provide our perspective on an inclusive approach and re-imagine how the academic, research, business and public policy sectors can support and incentivize the changes needed to raise the level of ambition and achieve sustainable development goals (SDG), considering actions from the farm to the national scale

Densidade populacional e dinâmica do perfilhamento em capim-marandu submetido a estratégias de pastejo rotativo e adubação nitrogenada

The objective of this experiment was to evaluate tiller population density and the dynamics of the tillering process in marandu palisade grass subjected to strategies of rotational stocking management and nitrogen fertilization. Treatments corresponded to combinations between two targets of pre-grazing conditions (sward surface height of 25 and 35 cm) and two rates of nitrogen application (50 and 200 kg ha-1 year-1), and were allocated to experimental units according to a 2 x 2 factorial arrangement in a randomised complete block design, with four replications. The following response variables were studied: initial (TPDi), intermediate (TPDm) and final (TPDf) tiller population density as well as the rates of tiller appearance (TAR) and death (TDR) and the tiller population stability index (SI). TPDi was similar to all treatments, with differences in tiller population density becoming more pronounced as the experiment progressed, resulting in larger TPDf on swards managed at 25 cm pre-grazing height. Tiller death was larger on swards managed at 35 cm, with differences in tiller appearance being recorded only from February 2010 onwards. Stability of tiller population was higher on swards managed at 25 cm pre-grazing height. Overall, there was no effect of nitrogen on the studied variables, and the most adequate grazing strategy corresponded to the pre-grazing height of 25 cm, regardless of the nitrogen application rate used

Weight gain and animal productivity on Marandu palisade grass under rotational stocking and nitrogen fertilization

O objetivo deste trabalho foi avaliar metas de manejo para capim-marandu (Urochloa brizantha cv. Marandu) submetido a pastejo rotativo e a doses de nitrogênio, de janeiro de 2009 a abril de 2010. Os tratamentos consistiram da combinação de duas frequências de pastejo (altura pré-pastejo de 25 e 35 cm) e de duas doses de fertilizante nitrogenado (50 e 200 kg ha-1 por ano) em delineamento de blocos ao acaso com arranjo fatorial 2x2 e quatro repetições. A altura de pós-pastejo estipulada foi de 15 cm. Maiores valores de ganho de peso médio por animal por dia (0,629 e 0,511 kg dia-1) e por hectare (886 e 674 kg ha-1), bem como de taxa de lotação (3,13 e 2,85 UA ha-1), foram observados nos pastos manejados com altura pré-pastejo de 25 cm. A aplicação de 200 kg ha-1 de N resultou em aumentos na percentagem de folhas na massa de forragem pós-pastejo, nas taxas de acúmulo de forragem, na taxa de lotação e no ganho de peso por área. A mais adequada estratégia de manejo corresponde à altura pré-pastejo de 25 cm, independentemente da dose de nitrogênio utilizada.The objective of this work was to assess management targets for marandu palisade grass (Urochloa brizantha cv. Marandu) subjected to rotational stocking and to nitrogen fertilization rates, from January 2009 to April 2010. Treatments consisted of a combination of two grazing frequencies (pre-grazing heights of 25 and 35 cm) and two levels of nitrogen application (50 and 200 kg ha-1 per year). in a completely randomized block design, in a 2x2 factorial arrangement, with four replicates. The established post-grazing height was 15 cm. Greater values of daily weight gain per animal per day (0.629 and 0.511 kg day-1), weight gain per hectare (886 and 674 kg ha-1), and stocking rate (3.13 and 2.85 AU ha-1) were found for pre-grazing height of 25 cm. The application of 200 kg ha-1 of N increased the percentage of leaves in post-grazing forage mass, forage accumulation rate, stocking rate, as well as weight gain per hectare. The best grazing strategy corresponds to the pre-grazing height of 25 cm, regardless of the nitrogen application

ISLES 2022: A multi-center magnetic resonance imaging stroke lesion segmentation dataset

Magnetic resonance imaging (MRI) is an important imaging modality in stroke. Computer based automated medical image processing is increasingly finding its way into clinical routine. The Ischemic Stroke Lesion Segmentation (ISLES) challenge is a continuous effort to develop and identify benchmark methods for acute and sub-acute ischemic stroke lesion segmentation. Here we introduce an expert-annotated, multicenter MRI dataset for segmentation of acute to subacute stroke lesions (https://doi.org/10.5281/zenodo.7153326). This dataset comprises 400 multi-vendor MRI cases with high variability in stroke lesion size, quantity and location. It is split into a training dataset of n = 250 and a test dataset of n = 150. All training data is publicly available. The test dataset will be used for model validation only and will not be released to the public. This dataset serves as the foundation of the ISLES 2022 challenge (https://www.isles-challenge.org/) with the goal of finding algorithmic methods to enable the development and benchmarking of automatic, robust and accurate segmentation methods for ischemic stroke

ISLES 2022: A multi-center magnetic resonance imaging stroke lesion segmentation dataset.

Magnetic resonance imaging (MRI) is an important imaging modality in stroke. Computer based automated medical image processing is increasingly finding its way into clinical routine. The Ischemic Stroke Lesion Segmentation (ISLES) challenge is a continuous effort to develop and identify benchmark methods for acute and sub-acute ischemic stroke lesion segmentation. Here we introduce an expert-annotated, multicenter MRI dataset for segmentation of acute to subacute stroke lesions ( https://doi.org/10.5281/zenodo.7153326 ). This dataset comprises 400 multi-vendor MRI cases with high variability in stroke lesion size, quantity and location. It is split into a training dataset of n = 250 and a test dataset of n = 150. All training data is publicly available. The test dataset will be used for model validation only and will not be released to the public. This dataset serves as the foundation of the ISLES 2022 challenge ( https://www.isles-challenge.org/ ) with the goal of finding algorithmic methods to enable the development and benchmarking of automatic, robust and accurate segmentation methods for ischemic stroke

Taking the steps toward sustainable livestock: our multidisciplinary global farm platform journey

International audienc