17 research outputs found
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Estimating nitrogen and phosphorus concentrations in streams and rivers, within a machine learning framework.
Funder: University of Cambridge, Department of ZoologyFunder: NASA NNX17AI74GNitrogen (N) and Phosphorus (P) are essential nutritional elements for life processes in water bodies. However, in excessive quantities, they may represent a significant source of aquatic pollution. Eutrophication has become a widespread issue rising from a chemical nutrient imbalance and is largely attributed to anthropogenic activities. In view of this phenomenon, we present a new geo-dataset to estimate and map the concentrations of N and P in their various chemical forms at a spatial resolution of 30 arc-second (âŒ1âkm) for the conterminous US. The models were built using Random Forest (RF), a machine learning algorithm that regressed the seasonally measured N and P concentrations collected at 62,495 stations across the US streams for the period of 1994-2018 onto a set of 47 in-house built environmental variables that are available at a near-global extent. The seasonal models were validated through internal and external validation procedures and the predictive powers measured by Pearson Coefficients reached approximately 0.66 on average
Recommended from our members
Estimating nitrogen and phosphorus concentrations in streams and rivers, within a machine learning framework.
Funder: University of Cambridge, Department of ZoologyFunder: NASA NNX17AI74GNitrogen (N) and Phosphorus (P) are essential nutritional elements for life processes in water bodies. However, in excessive quantities, they may represent a significant source of aquatic pollution. Eutrophication has become a widespread issue rising from a chemical nutrient imbalance and is largely attributed to anthropogenic activities. In view of this phenomenon, we present a new geo-dataset to estimate and map the concentrations of N and P in their various chemical forms at a spatial resolution of 30 arc-second (âŒ1âkm) for the conterminous US. The models were built using Random Forest (RF), a machine learning algorithm that regressed the seasonally measured N and P concentrations collected at 62,495 stations across the US streams for the period of 1994-2018 onto a set of 47 in-house built environmental variables that are available at a near-global extent. The seasonal models were validated through internal and external validation procedures and the predictive powers measured by Pearson Coefficients reached approximately 0.66 on average
Hydrography90m: a new high-resolution global hydrographic dataset
The geographic distribution of streams and rivers drives a multitude of patterns and processes in hydrology, geomorphology, geography, and ecology. Therefore, a hydrographic network that accurately delineates both small streams and large rivers, along with their topographic and topological properties, with equal precision would be indispensable in the earth sciences. Currently, available global hydrographies do not feature small headwater streams in great detail. However, these headwaters are vital because they are estimated to contribute to more than 70â% of overall stream length. We aimed to fill this gap by using the MERIT Hydro digital elevation model at 3âarcsec (âŒ90âm at the Equator) to derive a globally seamless, standardised hydrographic network, the âHydrography90mâ, with corresponding stream topographic and topological information. A central feature of the network is the minimal upstream contributing area, i.e. flow accumulation, of 0.05âkm2 (or 5âha) to initiate a stream channel, which allowed us to extract headwater stream channels in great detail. By employing a suite of GRASS GIS hydrological modules, we calculated the range-wide upstream flow accumulation and flow direction to delineate a total of 1.6 million drainage basins and extracted globally a total of 726 million unique stream segments with their corresponding sub-catchments. In addition, we computed stream topographic variables comprising stream slope, gradient, length, and curvature attributes as well as stream topological variables to allow for network routing and various stream order classifications. We validated the spatial accuracy and flow accumulation of Hydrography90m against NHDPlus HR, an independent, national high-resolution hydrographic network dataset of the United States. Our validation shows that the newly developed Hydrography90m has the highest spatial precision and contains more headwater stream channels compared to three other global hydrographic datasets. This comprehensive approach provides a vital and long-overdue baseline for assessing actual streamflow in headwaters and opens new research avenues for high-resolution studies of surface water worldwide. Hydrography90m thus offers significant potential to facilitate the assessment of freshwater quantity and quality, inundation risk, biodiversity, conservation, and resource management objectives in a globally comprehensive and standardised manner. The Hydrography90m layers are available at https://doi.org/10.18728/igb-fred-762.1 (Amatulli et al., 2022a), and while they can be used directly in standard GIS applications, we recommend the seamless integration with hydrological modules in open-source QGIS and GRASS GIS software to further customise the data and derive optimal utility from it
Bovine reproductive immunoinfertility: pathogenesis and immunotherapy
Infertility is one of the primary factors for cattle reproduction in the present scenario. Reproduction-related immunoinfertility mainly involves immunization against the antigens related to reproductive hormones (LHRH, GnRH, Gonadal steroids, PGF2α and oxytocin), spermatozoa, seminal plasma and ovum. Anovulation, delayed ovulation, sperm immobilization, failure of fertilization, prolonged uterine involution, extended calving interval, prolonged post-partum estrus and reduced conception rate could be a result of immunoinfertility that occur due to the blockage of receptor site by antibodies formed against hormones, sperm and ovum. Immunoinfertility can be treated in the animal by giving sexual rest to females, by using various reproductive technologies such as in-vitro fertilization, gamete intra fallopian tube transfer, and intracytoplasmic sperm injection, sperm washing and by treating the animals with immunomodulators such as LPS, Oyster glycogen, etc. This review summarizes the different causes of bovine reproductive immunoinfertility and amelioration strategies to overcome it
Correction to: Two years later: Is the SARS-CoV-2 pandemic still having an impact on emergency surgery? An international cross-sectional survey among WSES members
Background: The SARS-CoV-2 pandemic is still ongoing and a major challenge for health care services worldwide. In the first WSES COVID-19 emergency surgery survey, a strong negative impact on emergency surgery (ES) had been described already early in the pandemic situation. However, the knowledge is limited about current effects of the pandemic on patient flow through emergency rooms, daily routine and decision making in ES as well as their changes over time during the last two pandemic years. This second WSES COVID-19 emergency surgery survey investigates the impact of the SARS-CoV-2 pandemic on ES during the course of the pandemic.
Methods: A web survey had been distributed to medical specialists in ES during a four-week period from January 2022, investigating the impact of the pandemic on patients and septic diseases both requiring ES, structural problems due to the pandemic and time-to-intervention in ES routine.
Results: 367 collaborators from 59 countries responded to the survey. The majority indicated that the pandemic still significantly impacts on treatment and outcome of surgical emergency patients (83.1% and 78.5%, respectively). As reasons, the collaborators reported decreased case load in ES (44.7%), but patients presenting with more prolonged and severe diseases, especially concerning perforated appendicitis (62.1%) and diverticulitis (57.5%). Otherwise, approximately 50% of the participants still observe a delay in time-to-intervention in ES compared with the situation before the pandemic. Relevant causes leading to enlarged time-to-intervention in ES during the pandemic are persistent problems with in-hospital logistics, lacks in medical staff as well as operating room and intensive care capacities during the pandemic. This leads not only to the need for triage or transferring of ES patients to other hospitals, reported by 64.0% and 48.8% of the collaborators, respectively, but also to paradigm shifts in treatment modalities to non-operative approaches reported by 67.3% of the participants, especially in uncomplicated appendicitis, cholecystitis and multiple-recurrent diverticulitis.
Conclusions: The SARS-CoV-2 pandemic still significantly impacts on care and outcome of patients in ES. Well-known problems with in-hospital logistics are not sufficiently resolved by now; however, medical staff shortages and reduced capacities have been dramatically aggravated over last two pandemic years
Estimating nitrogen and phosphorus concentrations in streams and rivers across the Contiguous United States
Nitrogen (N) and Phosphorus (P) are essential nutritional elements for life processes in water bodies. However, in excessive quantities, they may represent a significant source of aquatic pollution. Eutrophication has become a widespread issue rising from a chemical nutrient imbalance and is largely attributed to anthropogenic activities. In view of this phenomenon, we present a new geo-dataset to estimate and map the concentrations of N and P in their various chemical forms at a spatial resolution of 30 arc-second (~1 km) for the conterminous US. The models were built using Random Forest (RF), a machine learning algorithm that regressed the seasonally measured N and P concentrations collected at 62,495 stations across the US streams for the period of 1994-2018 onto a set of 47 in-house built environmental variables that are available at a near-global extent. The seasonal models were validated through internal and external validation procedures and the predictive powers measured by Pearson Coefficients reached approximately 0.66 on average
Geomorpho90m - Global high-resolution geomorphometry layers: empirical evaluation and accuracy assessment. Geomorphological landform layers.
Geomorphometry is the science of quantitative analysis of the Earth's surface. The primary inputs for such terrain analyses are remotely sensed Digital Elevation Models (DEMs), which provide an opportunity to derive a wide range of environmental variables to better understand patterns and processes in geography, geology, climatology, hydrology or biodiversity science. While DEMs provide the elevation itself, a wide array of geomorphometry metrics can be extracted to yield information regarding topographical variation and land surface parameters, to improve our understanding of the geographical, geomorphological and environmental properties of a given study area. By the elevation it is possible to describe the topographical complexity, which can shape the macro and micro climate of a given area. The topographical variation contributes significantly to the environmental complexity of a region, and also defines the biotic and abiotic features at a sub-regional level.
Land surface parameters are quantitative measures of various morphometric properties of a surface. The most common parameters, slope or aspect, can be used to further derive more complex features or curvature profiles of a terrain at any given location. Such measures are pivotal to reflect hydrological parameters shaping flow and erosion processes within the landscape, and to delineate catchment and stream features. Moreover, mapping and assessing landform variability such as concavity and convexity is essential to gaining a better picture of the dynamics of land erosion and landscape denudation in mountainous environments
A unique finding of normal aldosterone level in Bartterâs syndrome
Background: Bartterâs syndrome is a rare autosomal recessive renal tubular disorder characterized by hypokalemia, hypochloremia, metabolic alkalosis, hyperreninemia and hyperaldosteronemia with normotension. Bartter syndrome has five types; type 1 (mutation in sodium/potassium chloride transporter), type 2 (mutation in voltage gated potassium channel), type 3 (mutation on chromosome 1 that encodes Barttin and makes only kidney-specific chloride channel B non-functional), type 4 ( mutation in BSND gene encoding Barttin and makes both kidney-specific chloride channels A & B non-functional) and type 5 (L125P gain in function mutation in calcium-sensing receptor). Case Presentation: A 28-year-old male was hospitalized for evaluation of nausea, vomiting, generalized weakness and persistent chronic hypokalemia. Bartterâs syndrome was suspected based on clinical and laboratory evidence, however serum aldosterone level was normal. Further genetic testing confirmed the diagnosis of Bartterâs syndrome type 3. Conclusions: We report a case of Bartterâs syndrome type 3 with a unique finding of normal aldosterone level