66 research outputs found
Wildfire danger prediction and understanding with deep learning
The authors thank Fabian Gans who provided the instructions to deploy the data cube in a cloud‐optimized format.
Publisher Copyright:
© 2022 The Authors.Climate change exacerbates the occurence of extreme droughts and heatwaves, increasing the frequency and intensity of large wildfires across the globe. Forecasting wildfire danger and uncovering the drivers behind fire events become central for understanding relevant climate-land surface feedback and aiding wildfire management. In this work, we leverage Deep Learning (DL) to predict the next day's wildfire danger in a fire-prone part of the Eastern Mediterranean and explainable Artificial Intelligence (xAI) to diagnose model attributions. We implement DL models that capture the temporal and spatio-temporal context, generalize well for extreme wildfires, and demonstrate improved performance over the traditional Fire Weather Index. Leveraging xAI, we identify the substantial contribution of wetness-related variables and unveil the temporal focus of the models. The variability of the contribution of the input variables across wildfire events hints into different wildfire mechanisms. The presented methodology paves the way to more robust, accurate, and trustworthy data-driven anticipation of wildfires.publishersversionpublishe
Inositols: From established knowledge to novel approaches
Myo-inositol (myo-Ins) and D-chiro-inositol (D-chiro-Ins) are natural compounds involved in many biological pathways. Since the discovery of their involvement in endocrine signal transduction, myo-Ins and D-chiro-Ins supplementation has contributed to clinical approaches in ameliorating many gynecological and endocrinological diseases. Currently both myo-Ins and D-chiro-Ins are well-tolerated, effective alternative candidates to the classical insulin sensitizers, and are useful treatments in preventing and treating metabolic and reproductive disorders such as polycystic ovary syndrome (PCOS), gestational diabetes mellitus (GDM), and male fertility disturbances, like sperm abnormalities. Moreover, besides metabolic activity, myo-Ins and D-chiro-Ins deeply influence steroidogenesis, regulating the pools of androgens and estrogens, likely in opposite ways. Given the complexity of inositol-related mechanisms of action, many of their beneficial effects are still under scrutiny. Therefore, continuing research aims to discover new emerging roles and mechanisms that can allow clinicians to tailor inositol therapy and to use it in other medical areas, hitherto unexplored. The present paper outlines the established evidence on inositols and updates on recent research, namely concerning D-chiro-Ins involvement into steroidogenesis. In particular, D-chiro-Ins mediates insulin-induced testosterone biosynthesis from ovarian thecal cells and directly affects synthesis of estrogens by modulating the expression of the aromatase enzyme. Ovaries, as well as other organs and tissues, are characterized by a specific ratio of myo-Ins to D-chiro-Ins, which ensures their healthy state and proper functionality. Altered inositol ratios may account for pathological conditions, causing an imbalance in sex hormones. Such situations usually occur in association with medical conditions, such as PCOS, or as a consequence of some pharmacological treatments. Based on the physiological role of inositols and the pathological implications of altered myo-Ins to D-chiro-Ins ratios, inositol therapy may be designed with two different aims: (1) restoring the inositol physiological ratio; (2) altering the ratio in a controlled way to achieve specific effects
When one size does not fit all: Reconsidering PCOS etiology, diagnosis, clinical subgroups, and subgroup-specific treatments
Polycystic Ovary Syndrome (PCOS) is a complex endocrine disorder that affects a large proportion of women. Due to its heterogeneity, the best diagnostic strategy has been a matter of contention. Since 1990 scientific societies in the field of human reproduction have tried to define the pivotal criteria for the diagnosis of PCOS. The consensus Rotterdam diagnostic criteria included the presence of hyperandrogenism, oligo/anovulation, and polycystic ovarian morphology (PCOM), and have now been updated to evidence based diagnostic criteria in the 2018 and 2023 International Guideline diagnostic criteria endorsed by 39 societies internationally. Within the Rotterdam Criteria, at least two out of three of the above-mentioned features are required to be present to diagnose PCOS, resulting in four phenotypes being identified: phenotype A, characterized by the presence of all the features, phenotype B, exhibiting hyperandrogenism and oligo-anovulation, phenotype C, presenting as hyperandrogenism and PCOM and finally the phenotype D that is characterized by oligo-anovulation and PCOM, lacking the hyperandrogenic component. However, it is the hypothesis of the EGOI group that the Rotterdam phenotypes A, B, and C have a different underlying causality to phenotype D. Recent studies have highlighted the strong correlation between insulin resistance and hyperandrogenism, and the pivotal role of these factors in driving ovarian alterations, such as oligo-anovulation and follicular functional cyst formation. This new understanding of PCOS pathogenesis has led the authors to hypothesis that phenotypes A, B, and C are endocrine-metabolic syndromes with a metabolic clinical onset. Conversely, the absence of hyperandrogenism and metabolic disturbances in phenotype D suggests a different origin of this condition, and point towards novel pathophysiological mechanisms; however, these are still not fully understood. Further questions have been raised regarding the suitability of the “phenotypes” described by the Rotterdam Criteria by the publication by recent GWAS studies, which demonstrated that these phenotypes should be considered clinical subtypes as they are not reflected in the genetic picture. Hence, by capturing the heterogeneity of this complex disorder, current diagnostic criteria may benefit from a reassessment and the evaluation of additional parameters such as insulin resistance and endometrial thickness, with the purpose of not only improving their diagnostic accuracy but also of assigning an appropriate and personalized treatment. In this framework, the present overview aims to analyze the diagnostic criteria currently recognized by the scientific community and assess the suitability of their application in clinical practice in light of the newly emerging evidence
Vernonia cinerea Less. supplementation and strenuous exercise reduce smoking rate: relation to oxidative stress status and beta-endorphin release in active smokers
<p>Abstract</p> <p>Purpose</p> <p>The aim of this study was to evaluate the effects of <it>Vernonia cinerea </it>Less. (VC) supplementation and exercise on oxidative stress biomarkers, beta-endorphin release, and the rate of cigarette smoking.</p> <p>Methods</p> <p>Volunteer smokers were randomly divided into four groups: group 1: VC supplement; group 2: exercise with VC supplement; group 3: exercise; and group 4: control. VC was prepared by wash and dry techniques and taken orally before smoking, matching the frequency of strenuous exercise (three times weekly). Before and after a two month period, exhaled carbon monoxide (CO), blood oxidative stress (malondialdehyde [MDA], nitric oxide [NOx], protein hydroperoxide [PrOOH] and total antioxidant capacity [TAC]), beta-endorphin and smoking rate were measured, and statistically analyzed.</p> <p>Results</p> <p>In Group 1, MDA, PrOOH, and NOx significantly decreased, whereas TAC increased (p < 0.05). In Group 2, MDA and PrOOH decreased (p < 0.05), with no other changes noted (p > 0.05). In Group 3, MDA, PrOOH, NOx, TAC, and beta-endorphin levels increased significantly (p < 0.05). Group 4 showed no change in oxidative stress variables or beta-endorphine levels (p > 0.05). All groups had lower levels of CO after the intervention. The smoking rate for light cigarette decreased in group 2(62.7%), 1(59.52%), 3 (53.57%) and 4(14.04%), whereas in self-rolled cigarettes it decreased in group 1 (54.47%), 3 (42.30%), 2 (40%) and 4 (9.2%).</p> <p>Conclusion</p> <p>Supplementation with <it>Vernonia cinerea </it>Less and exercise provided benefit related to reduced smoking rate, which may be related to oxidaive stress and beta-endorphine levels.</p
Total Arterial Revascularization: The Case for BIMA
Sotirios Prapas of the Henry Dunant Hospital Center in Athens, Greece, discusses the technique of off-pump coronary artery bypass using two internal mammary arteries (IMAs). He presents the different grafting techniques and reviews patient outcomes with this off-pump, IMA-only approach.<div>This presentation was originally given during the SCTS Ionescu University program at the 2017 Annual Meeting of the Society for Cardiothoracic Surgery in Great Britain and Ireland. This content is published with the permission of <a href="https://scts.org/">SCTS</a>. Please <a href="https://sctsed.org/">click here</a> for more information on SCTS educational programs.<br></div
Multigrid algorithm implementation on parallel architectures
111 σ.Σε έναν μεγάλο αριθμό φυσικών και μαθηματικών προβλημάτων, χρειάζεται να γίνεται μοντελοποίηση με μερικές διαφορικές εξισώσεις προκειμένου να καθιστάται δυνατή η επίλυση. Τα προβλήματα αυτά πιθανόν να αφορούν φυσικά φαινόμενα πολύ διαφορετικά μεταξύ τους αλλά μπορούν όλα να λυθούν με μερικές διαφορικές εξισώσεις. Στην εργασία αυτή ασχολούμαστε με τη μελέτη και την υλοποίηση αλγορίθμων που επιλύουν τέτοια προβλήματα. Το πρόβλημα που εξετάζουμε σε αυτή την εργασία αφορά την επίλυση γραμμικών ελλειπτικών μερικών διαφορικών εξισώσεων (εξίσωση του Poisson και εξίσωση του Laplace) και συγκεκριμένα είναι το πρόβλημα Dirichlet σε δύο και σε τρεις διαστάσεις.
Μελετάμε αρχικά τον αλγόριθμο επίλυσης που βασίζεται στη μέθοδο Jacobi, μια γραμμική επαναληπτική μέθοδο επίλυσης. Ωστόσο, ο αλγόριθμος που μας ενδιαφέρει κυρίως είναι αυτός που προκύπτει χρησιμοποιώντας πολυπλεγματικές τεχνικές. Τέτοιες τεχνικές χρησιμοποιούνται ευρύτατα σε εφαρμογές ελλειπτικών μερικών διαφορικών εξισώσεων. Συνεπώς, τα συμπεράσματα που θα εξάγουμε μπορούν με ασφάλεια να γενικευθούν για μια μεγάλη ομάδα εφαρμογών επίλυσης μερικών διαφορικών εξισώσεων. Οι πολυπλεγματικές τεχνικές χρησιμεύουν στην αποδοτική επίλυση μιας πληθώρας γραμμικών επαναληπτικών προβλημάτων και συνδυαζόμενες με διάφορες τεχνικές διακριτοποίησης, αναδεικνύουν μια από τις ταχύτερες μεθόδους επίλυσης φυσικών και μαθηματικών προβλημάτων.
Η υλοποίηση του αλγορίθμου γίνεται σε γλώσσα C και με χρήση των εργαλείων που προσφέρουν δύο πολύ διαδεδομένες διεπαφές προγραμματισμού εφαρμογών, το OpenMP και το MPI. Προσπαθούμε με αυτό τον τρόπο να εκμεταλλευτούμε τα περιθώρια παραλληλοποίησης του αλγορίθμου. Μας απασχολεί ιδιαίτερα η εκτέλεσή του σε υπολογιστικό σύστημα παράλληλης αρχιτεκτονικής, είτε κοινής είτε κατανεμημένης μνήμης. Το υπολογιστικό αυτό σύστημα είναι στην ουσία μια συστοιχία υπολογιστικών κόμβων, για την οποία μπορούμε να επιλέξουμε δίκτυο διασύνδεσης είτε το Ethernet είτε το Myrinet.In a large number of physical and mathematical problems, modeling with use of partial differential equations becomes a necessity for their solution finding procedure. These problems may vary considerably in respect to the phenomena they deal with. However, all of them can be solved using partial differential equations. In this thesis we study and implement algorithms that solve such problems. The problem under examination concerns the solution of linear elliptic partial differential equations (Poisson’s equation and Laplace’s equation). More specifically, it is the Dirichlet problem in two and three dimensions.
We initially consider the algorithm based on the Jacobi method, a linear iterative solution method. However, our primary concern lies in the algorithm resulting from the use of multigrid methods. Such methods are being used widely in applications involving elliptic partial differential equations. Therefore, our conclusions can be safely generalized to concern a broad group of applications solving partial differential equations. Multigrid methods are used to efficiently solve a plethora of linear iterative problems. Combined with various disretization techniques, they generate one of the fastest solving methods for physical and mathematical problems.
We build the algorithm using the C programming language and additional tools offered by two widespread application programming interfaces, OpenMP and MPI. Thus, we attempt to exploit the parallelization potentialities of the algorithm. We mainly care for its implementation on a parallel computing system of either distributed memory or shared memory architecture. This computing system is merely an array of computing elements, for which we can select the interconnection network to be either Ethernet or Myrinet.Δημήτριος Ν. Πράπα
Supplementation with D-chiro-inositol in women
The world of natural compounds has been investigated with the aim of discovering possible medical applications ever since the origin of medicine. Recently, the field of gynecology has developed a growing interest regarding inositols. Inositols are cyclic polyols with a key role in many metabolic pathways. Their stability throughout the evolution of life can mark these molecules as prebiotic, due to their biochemical importance. These molecules can be classified into nine stereoisomeric compounds; among them, myo-inositol (MI) is the most important and frequent form found in nature. Inositols were first discovered in 1850 by Johanes Joseph Scherer and extracted from muscle cells, the name of which still persist in the compound (myo¼muscle in greek). In humans, inositols are derived from the diet in the primary form of MI. Subsequently, MI can be unidirectionally converted into different forms such as D-chiro-inositol (DCI), thanks to insulin action, and with the action of a specific nicotinamide adenine dinucleotide (NAD)-NADH-dependent epimerase. The primary focus of this chapter is to examine and discuss the biochemical properties of DCI and its clinical implication. In particular, it will provide the details of possible clinical applications of DCI supplementation in women, considering the principal biochemical effects
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