Short reasons for long vectors in HPC CPUs: a study based on RISC-V

For years, SIMD/vector units have enhanced the capabilities of modern CPUs in High-Performance Computing (HPC) and mobile technology. Typical commercially-available SIMD units process up to 8 double-precision elements with one instruction. The optimal vector width and its impact on CPU throughput due to memory latency and bandwidth remain challenging research areas. This study examines the behavior of four computational kernels on a RISC-V core connected to a customizable vector unit, capable of operating up to 256 double precision elements per instruction. The four codes have been purposefully selected to represent non-dense workloads: SpMV, BFS, PageRank, FFT. The experimental setup allows us to measure their performance while varying the vector length, the memory latency, and bandwidth. Our results not only show that larger vector lengths allow for better tolerance of limitations in the memory subsystem but also offer hope to code developers beyond dense linear algebra.Comment: Accepted as paper at the Second RISC-V Workshops at SC23 - Denve

In situ control of graphene oxide dispersions with a small impedance sensor

Abstract Carbon-based nanomaterials (CBNs), such as graphene and carbon nanotubes, display advanced physical and chemical properties, which has led to their widespread applications. One of these applications includes the incorporation of CBNs into cementitious materials in the form of aqueous dispersions. The main issue that arises in this context is that currently no established protocol exists as far as characterizing the dispersions. In the present article, an innovative method for quick evaluation and quantification of graphene oxide (GO) dispersions is proposed. The proposed method is electrical impedance spectroscopy (EIS) with an impedance sensor. The novelty lies on the exploitation of a small sensor for on-site (field) direct dielectric measurements with the application of alternating current. Five different concentrations of GO dispersions were studied by applying EIS and for various accumulated ultrasonic energies. The low GO concentration leads to high impedance values due to low formed current network. Two opposing mechanisms were revealed during the accumulation of ultrasonic energy, that are taking place simultaneously: breakage of the agglomerates that facilitates the flow of the electric current due to the formation of a better dispersed network, nevertheless the surface hydrophilic structure of the GO is damaged with the high accumulated ultrasonic energy. The dielectric measurements were exploited to express an appropriate quantitative ‘quality index’ to facilitate with the dispersion control of the nanostructures. An intermediate concentration of GO is suggested (about 0.15 wt% of the binder materials) to be optimal for the specific engineering application, ultrasonicated at approximately 30 to 65 kJ. The investigated methodology is highly novel and displays a high potential to be applied in-field applications where CBNs must be incorporated in building materials

Performance and energy footprint assessment of FPGAs and GPUs on HPC systems using Astrophysics application

New challenges in Astronomy and Astrophysics (AA) are urging the need for a large number of exceptionally computationally intensive simulations. "Exascale" (and beyond) computational facilities are mandatory to address the size of theoretical problems and data coming from the new generation of observational facilities in AA. Currently, the High Performance Computing (HPC) sector is undergoing a profound phase of innovation, in which the primary challenge to the achievement of the "Exascale" is the power-consumption. The goal of this work is to give some insights about performance and energy footprint of contemporary architectures for a real astrophysical application in an HPC context. We use a state-of-the-art N-body application that we re-engineered and optimized to exploit the heterogeneous underlying hardware fully. We quantitatively evaluate the impact of computation on energy consumption when running on four different platforms. Two of them represent the current HPC systems (Intel-based and equipped with NVIDIA GPUs), one is a micro-cluster based on ARM-MPSoC, and one is a "prototype towards Exascale" equipped with ARM-MPSoCs tightly coupled with FPGAs. We investigate the behavior of the different devices where the high-end GPUs excel in terms of time-to-solution while MPSoC-FPGA systems outperform GPUs in power consumption. Our experience reveals that considering FPGAs for computationally intensive application seems very promising, as their performance is improving to meet the requirements of scientific applications. This work can be a reference for future platforms development for astrophysics applications where computationally intensive calculations are required.Comment: 15 pages, 4 figures, 3 tables; Preprint (V2) submitted to MDPI (Special Issue: Energy-Efficient Computing on Parallel Architectures

Heterogeneity of pollen food allergy syndrome in seven Southern European countries: The @IT.2020 multicenter study

Background Pollen food allergy syndrome (PFAS) is a frequently underdiagnosed disease due to diverse triggers, clinical presentations, and test results. This is especially relevant in geographic areas with a broad spectrum of pollen sensitization, such as Southern Europe. Objectives To elucidate similarities and differences of PFAS in nine Southern European centers and identify associated characteristics and unique markers of PFAS. Methods As part of the @IT.2020 Multicenter Study, 815 patients with seasonal allergic rhinitis (SAR), aged 10-60 years, were recruited in seven countries. They completed questionnaires regarding SAR, comorbidities, family history, and PFAS, and underwent skin prick testing (SPT) and serum IgE testing. Results Of the 815 patients, 167 (20.5%) reported PFAS reactions. Most commonly, eliciting foods were kiwi (58, 34.7%), peach (43, 25.7%), and melon (26, 15.6%). Reported reactions were mostly local (216/319, 67.7%), occurring within 5 min of contact with elicitors (209/319, 65.5%). Associated characteristics included positive IgE to at least one panallergen (profilin, PR-10, or nsLTP) (p = 0.007), maternal PFAS (OR: 3.716, p = 0.026), and asthma (OR: 1.752, p = 0.073). Between centers, heterogeneity in prevalence (Marseille: 7.5% vs. Rome: 41.4%, p < 0.001) and of clinical characteristics was apparent. Cypress played a limited role, with only 1/22 SPT mono-sensitized patients reporting a food reaction (p < 0.073). Conclusions PFAS is a frequent comorbidity in Southern European SAR patients. Significant heterogeneity of clinical characteristics in PFAS patients among the centers was observed and may be related to the different pollen sensitization patterns in each geographic area. IgE to panallergen(s), maternal PFAS, and asthma could be PFAS-associated characteristics

“Whole” vs. “fragmented” approach to EAACI pollen season definitions: A multicenter study in six Southern European cities

Background: The adequate definition of pollen seasons is essential to facilitate a correct diagnosis, treatment choice, and outcome assessment in patients with seasonal allergic rhinitis. A position paper by the European Academy of Allergy and Clinical Immunology (EAACI) proposed season definitions for Northern and Middle Europe. Objective: To test the pollen season definitions proposed by EAACI in six Mediterranean cities for seven pollen taxa. Methods: As part of the @IT.2020 multi-center study, pollen counts for Poaceae, Oleaceae, Fagales, Cupressaceae, Urticaceae (Parietaria spp.), and Compositae (Ambrosia spp., Artemisia spp.) were collected from January 1 to December 31, 2018. Based on these data, pollen seasons were identified according to EAACI criteria. A unified monitoring period for patients in AIT trials was created and assessed for feasibility. Results: The analysis revealed a great heterogeneity between the different locations in terms of pattern and length of the examined pollen seasons. Further, we found a fragmentation of pollen seasons in several segments (max. 8) separated by periods of low pollen counts (intercurrent periods). Potential monitoring periods included often many recording days with low pollen exposure (max. 341 days). Conclusion: The Mediterranean climate leads to challenging pollen exposure times. Monitoring periods for AIT trials based on existing definitions may include many intermittent days with low pollen concentrations. Therefore, it is necessary to find an adapted pollen season definition as individual solution for each pollen and geographical area

Cabbage and fermented vegetables : From death rate heterogeneity in countries to candidates for mitigation strategies of severe COVID-19

Large differences in COVID-19 death rates exist between countries and between regions of the same country. Some very low death rate countries such as Eastern Asia, Central Europe, or the Balkans have a common feature of eating large quantities of fermented foods. Although biases exist when examining ecological studies, fermented vegetables or cabbage have been associated with low death rates in European countries. SARS-CoV-2 binds to its receptor, the angiotensin-converting enzyme 2 (ACE2). As a result of SARS-CoV-2 binding, ACE2 downregulation enhances the angiotensin II receptor type 1 (AT(1)R) axis associated with oxidative stress. This leads to insulin resistance as well as lung and endothelial damage, two severe outcomes of COVID-19. The nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is the most potent antioxidant in humans and can block in particular the AT(1)R axis. Cabbage contains precursors of sulforaphane, the most active natural activator of Nrf2. Fermented vegetables contain many lactobacilli, which are also potent Nrf2 activators. Three examples are: kimchi in Korea, westernized foods, and the slum paradox. It is proposed that fermented cabbage is a proof-of-concept of dietary manipulations that may enhance Nrf2-associated antioxidant effects, helpful in mitigating COVID-19 severity.Peer reviewe

Nrf2-interacting nutrients and COVID-19 : time for research to develop adaptation strategies

There are large between- and within-country variations in COVID-19 death rates. Some very low death rate settings such as Eastern Asia, Central Europe, the Balkans and Africa have a common feature of eating large quantities of fermented foods whose intake is associated with the activation of the Nrf2 (Nuclear factor (erythroid-derived 2)-like 2) anti-oxidant transcription factor. There are many Nrf2-interacting nutrients (berberine, curcumin, epigallocatechin gallate, genistein, quercetin, resveratrol, sulforaphane) that all act similarly to reduce insulin resistance, endothelial damage, lung injury and cytokine storm. They also act on the same mechanisms (mTOR: Mammalian target of rapamycin, PPAR gamma:Peroxisome proliferator-activated receptor, NF kappa B: Nuclear factor kappa B, ERK: Extracellular signal-regulated kinases and eIF2 alpha:Elongation initiation factor 2 alpha). They may as a result be important in mitigating the severity of COVID-19, acting through the endoplasmic reticulum stress or ACE-Angiotensin-II-AT(1)R axis (AT(1)R) pathway. Many Nrf2-interacting nutrients are also interacting with TRPA1 and/or TRPV1. Interestingly, geographical areas with very low COVID-19 mortality are those with the lowest prevalence of obesity (Sub-Saharan Africa and Asia). It is tempting to propose that Nrf2-interacting foods and nutrients can re-balance insulin resistance and have a significant effect on COVID-19 severity. It is therefore possible that the intake of these foods may restore an optimal natural balance for the Nrf2 pathway and may be of interest in the mitigation of COVID-19 severity

Priesthood in Old Testament

The purpose of the thesis was the research of priesthood in ancient Israel ac-cording to Old Testament texts. The analysis of the theme is presented in three parts. The first part deals with the priests of Ancient Near East, Sumer, Assyrian-Babylonian, in Canaan and in ancient Egypt. In the extra-biblical en-vironment the king participates in the worship, there are high priests and sec-ond class priests and also there are duties and activities of the priests in the worship and also in the temple and cultic affairs. The second part examines the priesthood in biblical Israel, from the desert period until the end of pre-exilic period. There is an analysis of Moses, Zadok, Eli the priest, Levites and Josiah’s religious reform. In the third part of the thesis there was a presenta-tion of the development of Israel’s priesthood from the post-exilic period since the Hellenistic period, according to the books of Ezekiel, Chronicles, Priestly Code and the books of Maccabees. There is an analysis of Aaron, about the duties and activities of priests and the first and second class structure of post-exilic priesthood. There is also an analysis of the high priests and the Levites in the worship and cultic affairs.Σκοπός της διατριβής είναι η μελέτη του θεσμού της ιεροσύνης στον βιβλικό Ισραήλ με βάση τα κείμενα της Παλαιάς Διαθήκης. Η διαπραγμάτευση του θέματος πραγματοποιείται σε τρία μέρη. Στο Α′ μέρος εξετάζεται το ιερατείο στους λαούς της Αρχαίας Εγγύς Ανατολής, στους Σουμέριους, Ασσύριους-Βαβυλώνιους, στη Χαναάν, τους Χετταίους και την αρχαία Αίγυπτο. Στο ε-ξωβιβλικό περιβάλλον παρατηρείται η συμμετοχή του βασιλιά στο ιερατείο, η διάρθρωση του ιερατείου σε ανώτερο και κατώτερο κλήρο καθώς επίσης και τα καθήκοντα και οι υποχρεώσεις των ιερέων στη λατρεία και στο ναό. Στο Β′ μέρος εξετάζεται η πορεία της ιεροσύνης από την πρώιμη περίοδο της ιστο-ρίας του Ισραήλ έως και το τέλος της προαιχμαλωσιακής περιόδου. Αναλύο-νται ο Μωυσής, ο Σαδώκ, ο ιερέας Ηλί, οι Λευίτες καθώς επίσης και η θρη-σκευτική μεταρρύθμιση του Ιωσία. Στο Γ′ μέρος εξετάζεται η πορεία της εξέ-λιξης του ιερατείου μετά την περίοδο της αιχμαλωσίας, έως και την ελληνι-στική περίοδο, σύμφωνα με τα βιβλία του προφήτη Ιεζεκιήλ, του Χρονικο-γράφου, του Ιερατικού Κώδικα και των βιβλίων των Μακκαβαίων. Υπάρχουν αναφορές για τον Ααρών, καθώς και για τη διάρθρωση και τα καθήκοντα των ιερέων κατά τη μεταιχμαλωσιακή περίοδο. Εξετάζεται επίσης το καθεστώς των αρχιερέων και των Λευιτών στη θέση της λατρείας και του ιερατείου

Three-dimensional simulation of pipe line extrusion with the finite elements method (FEM)

94 σ.Η εκβολή αποτελεί μια από τις ευρύτερα χρησιμοποιούμενες τεχνικές τόσο για τη μορφοποίηση όσο και για την ανάμειξη πολυμερών. Κύριο τμήμα της γραμμής παραγωγής προϊόντων με την μέθοδο της εκβολής είναι η μήτρα του εκβολέα. Η μήτρα που μελετάται και επιχειρείται να βελτιστοποιηθεί στην παρούσα εργασία φέρει μονή κεφαλή τύπου αράχνης. Στόχος της βελτιστοποίησης είναι ο εντοπισμός των καλύτερων τιμών των χαρακτηριστικών παραμέτρων της μήτρας του εκβολέα που καθορίζουν την ροή του επεξεργαζόμενου πολυμερούς. Έχει παρατηρηθεί ότι η ύπαρξη του ποδιού της αράχνης δημιουργεί ανωμαλίες στην επιφάνεια του παραγόμενου προϊόντος, με αρνητικές συνέπειες στην αντοχή του. Η παρούσα εργασία επιχειρεί να αυξήσει την αποδοτικότητα της μήτρας εκβολής πλαστικού σωλήνα του Τομέα Τεχνολογίας των Κατεργασιών. Με δεδομένο ότι οι αρχικές και οι οριακές συνθήκες της ροής ποικίλουν κατά την παραγωγική διαδικασία (επεξεργαζόμενο υλικό, συνθήκες περιβάλλοντος, πίεση εισόδου στην μήτρα κ.α.), εξετάζονται οι βασικότερες μεταβλητές που αφορούν την γεωμετρία της μήτρας και επηρεάζουν την ροή (μήκος εξόδου της μήτρας, γεωμετρία του ποδιού της αράχνης). Η βελτιστοποίηση πραγματοποιείται με μία σειρά προσομοιώσεων χρησιμοποιώντας τα λογισμικά στο SolidWorks® και Comsol® χρησιμοποιώντας την μέθοδο Taguchi. Η παρουσίαση και η ανάλυση των αποτελεσμάτων των προσομοιώσεων, δίνουν τον βαθμό εξάρτησης της ταχύτητας εξόδου υλικού και της αντοχής της μήτρας του εκβολέα με τις παραμέτρους που εξετάζονται και επιλέγονται οι βέλτιστες τιμές τους.Extrusion constitutes one of the most widely techniques for formatting and polymers mixture. Main part of production line of products with extrusion method is die of extruder. The die that is studied and attempted to be optimised in the present work has single type head of spider. Objective of optimisation is the discovery of better values of characteristic parameters of die of extruder that determine the flow of the working polymere. It has been observed that the existence of leg of spider creates abnormalities in the surface of product, with negative consequences in his resistance. The present work attempts to increase the efficiency of extrusion’s die of plastic pipe at Section of Manufacturing Technology. With datum that the initial and marginal conditions of flow vary at the productive process (processing material, conditions of environment, pressure of entry in the die etc), are examined the more basic variables according the geometry of die and influence the flow (output length of die, geometry of leg of spider). The optimisation is being with a line of simulations using the software of SolidWorks® and Comsol® using the Taguchi method. The presentation and the analysis of simulation results, give the dependence degree of material’s output speed and the die of extruder’s resistance with the parameters that are examined and selected their most optimal values.Νικόλαος Ε. Δήμο