Software tools for manipulating fe mesh, virtual surgery and post-processing

This paper describes a set of software tools which we developed for the calculation of fluid flow through cardiovascular organs. Our tools work with medical data from a CT scanner, but could be used with any other 3D input data. For meshing we used a Tetgen tetrahedral mesh generator, as well as a mesh re-generator that we have developed for conversion of tetrahedral elements into bricks. After adequate meshing we used our PAKF solver for calculation of fluid flow. For human-friendly presentation of results we developed a set of post-processing software tools. With modification of 2D mesh (boundary of cardiovascular organ) it is possible to do virtual surgery, so in a case of an aorta with aneurism, which we had received from University Clinical center in Heidelberg from a multi-slice 64-CT scanner, we removed the aneurism and ran calculations on both geometrical models afterwards. The main idea of this methodology is creating a system that could be used in clinics

Bezbednosni rizici klimatskih promena - studija slučaja Beograda

Based on the negative impact of climate change, the aim of quantitative research is to examine models for predicting the impact of demographic and sociocultural factors on citizens' attitudes to security risks of climate change. Using the random sample method, during the 2019, a survey of citizens was conducted in Belgrade's central square and included 438 respondents. The results of the research show that the conceived prediction model is statistically significant, and that the attitude of the respondents is influenced by different predictors, the most important of which is the level of education, age and sex of the respondents. Starting from the obtained research results, it is necessary to devise and implement educational programs for improving the awareness of citizens about the negative implications of climate change.Polazeći od negativnih uticaja klimatskih promena, cilj kvantitativnog istraživanja predstavlja ispitivanje modela za predikciju uticaja demografskih i socio-kulturnih faktora na stavove građana o bezbednosnim rizicima klimatskih promena. Korišćenjem metode slučajnog uzorka, u toku 2019. godine, sprovedeno je anketiranje građana na centralnom gradskom trgu u Beogradu i obuhvaćeno je 438 ispitanika. Rezultati istraživanja pokazuju da je koncipirani predikcioni model statistički značajan, kao i da na stavove ispitanika utiču različiti prediktori od kojih su najznačajniji nivo obrazovanja, godine starosti i pol ispitanika. Polazeći od dobijenih rezultata istraživanja, potrebno je osmisliti i implementirati edukativne programe unapređivanja svesti građana o negativnim implikacijama klimatskih promena

Fizičke karakteristike i nutritivni kvalitet odabranih genotipova kukuruza iz srbije različitih u tvrdoći i boji zrna

Physical quality traits (1000-kernel weight, density, milling response and soft endosperm portion), basic chemical (starch, protein, oil, cellulose and ash) and amino acids composition of ten ZP maize genotypes differing in kernel hardness and colour were studied. The objectives of this study were to characterize differences in ZP maize genotypes regarding to various physical traits and nutritional quality parameters such as basic chemical and amino acid composition and the data was correlated to find the interrelationship between these parameters. Kernel physical traits and chemical composition significantly varied among tested genotypes. A significant negative correlation was found between protein content and portion of soft endosperm as well as a significant positive correlation between protein content and two physical traits, milling response and density. Protein content showed a non-significant negative correlation with starch content. The results showed that the protein content exhibited negative correlation with lysine as well as positive correlation with methionine. It has not been observed a significant improvement in the amino acid composition regarding the specialty genotypes such as the selected white and red kernels and popping maize genotypes. The information presented in this study could be useful for the utilization improvement of maize kernel and the development of maize-based ingredients to prepare nutritious feed and food products.Ispitivane su fizičke karakteristike zrna (apsolutna masa ili masa 1000 zrna, gustina, otpornost na mlevenje i udeo meke frakcije endosperma), osnovni hemijski sastav (sadržaj skroba, proteina, ulja, celuloze i pepela) i sastav aminokiselina kod 10 genotipova kukuruza različitih po tvrdoći i boji zrna. Ciljevi ovog rada bili su da se izvrši karakterizacija ZP genotipova kukuruza u odnosu na različite fizičke osobine i nutritivne parametre kvaliteta kao što su osnovni hemijski i aminokiselinski sastav, i podaci potom korelacionom analizom obrade u cilju utvrđivanja međuodnosa ovih parametara kvaliteta. Fizičke osobine zrna i hemijski sastav značajno su varirali između ispitivanih genotipova. Utvrđena je značajna negativna korelacija između sadržaja proteina i udela meke frakcije endosperma kao i značajne pozitivne korelacije između sadržaja proteina i dve fizičke osobine, otpornost na mlevenje i gustina zrna. Sadržaj proteina pokazao je negativnu korelaciju sa sadržajem skroba. Rezultati su pokazali da sadržaj proteina u zrnu ima negativnu korelaciju sa sadržajem lizina, kao i pozitivnu korelaciju sa sadržajem metionina. Nije utvrđeno značajno poboljšanje sastava aminokiselina kod genotipova specifičnih svojstava, kao što su genotipovi belog i crvenog zrna, i genotipovi kukuruza kokičara. Informacije predstavljene u ovom radu mogu biti korisne za poboljšanje upotrebne vrednosti zrna kukuruza i razvoj komponenata na bazi kukuruza za hranu za životinje i prehrambene proizvode

Ancient genomes provide insights into family structure and the heredity of social status in the early Bronze Age of southeastern Europe

Twenty-four palaeogenomes from Mokrin, a major Early Bronze Age necropolis in southeastern Europe, were sequenced to analyse kinship between individuals and to better understand prehistoric social organization. 15 investigated individuals were involved in genetic relationships of varying degrees. The Mokrin sample resembles a genetically unstructured population, suggesting that the community's social hierarchies were not accompanied by strict marriage barriers. We find evidence for female exogamy but no indications for strict patrilocality. Individual status differences at Mokrin, as indicated by grave goods, support the inference that females could inherit status, but could not transmit status to all their sons. We further show that sons had the possibility to acquire status during their lifetimes, but not necessarily to inherit it. Taken together, these findings suggest that Southeastern Europe in the Early Bronze Age had a significantly different family and social structure than Late Neolithic and Early Bronze Age societies of Central Europe

The genetic history of the Southern Arc: a bridge between West Asia and Europe

By sequencing 727 ancient individuals from the Southern Arc (Anatolia and its neighbors in Southeastern Europe and West Asia) over 10,000 years, we contextualize its Chalcolithic period and Bronze Age (about 5000 to 1000 BCE), when extensive gene flow entangled it with the Eurasian steppe. Two streams of migration transmitted Caucasus and Anatolian/Levantine ancestry northward, and the Yamnaya pastoralists, formed on the steppe, then spread southward into the Balkans and across the Caucasus into Armenia, where they left numerous patrilineal descendants. Anatolia was transformed by intra–West Asian gene flow, with negligible impact of the later Yamnaya migrations. This contrasts with all other regions where Indo-European languages were spoken, suggesting that the homeland of the Indo-Anatolian language family was in West Asia, with only secondary dispersals of non-Anatolian Indo-Europeans from the steppe

Испитивање ставова грађана о пружању помоћи угроженим људима и волонтирању за време катастрофа

The subject of quantitative research is to examine the factors influencing citizens' attitudes towards assisting vulnerable people and volunteering during natural disasters. In this paper, the authors examine the relationship between gender, age, level of education, marital status, employment, income level and perception of personal religiosity, and the attitudes to assisting vulnerable people and volunteering. Multiple-point random sampling was used to survey 2500 citizens in the area of 19 local communities endangered by the consequences of natural disasters. The results of the survey show that 29% of respondents would provide assistance to vulnerable people in the form of money, 18,2% in the form of food and water, 21,6% in clothing and footwear, 23,3% would volunteer, while 4,6% would engage in shelter centers for endangered people. In addition, it was found that there was no statistically significant relationship between the attitudes towards providing assistance in the form of money and the employment status. As well as, attitudes about volunteering and provision of food and water assistance are not related to the employment status of respondents, etc. The results of the research can be used to improve the management system in natural disasters and to create appropriate educational programs for establishing a more efficient and comprehensive system of assistance to vulnerable people and the operation of volunteer organizations.Предмет овог квантитативног истраживања представља испитивање фактора који утичу на формирање ставова грађана о пружању помоћи угроженим људима и волонтирању за време природних катастрофа. У раду аутори испитују повезаност пола, година старости, нивоа образовања, брачног статуса, запослености, висине прихода и перцепције личне религиозности са ставовима о пружању помоћи угроженим људима и волонтирању. Вишеетапним случајним узорковањем анкетирано је 2500 грађана на подручју 19 локалних заједница угрожених последицама природних катастрофа. Резултати истраживања показују да би 29% испитаника пружило помоћ угроженим људима у виду новца, 18,2% у виду хране и воде, 21,6% у виду одеће и обуће, 23,3% би волонтирало, док би се 4,6% ангажовало у центрима за пријем угрожених људи. Поред тога, утврђено је да не постоји статистички значајна повезаност ставова о пружању помоћи у виду новца са статусом запослености. Такође, ставови о волонтерству и пружању помоћи у виду хране и воде нису повезани са статусом запослености испитаника итд. Резултати истраживања могу бити искоришћени за унапређење система управљања у природним катастрофама и стварање одговарајућих образовних програма за успостављање ефикаснијег и свеобухватнијег система пружања помоћи угроженим људима и рада волонтерских организација

Failure Conditions Assessment of Complex Water Systems Using Fuzzy Logic

This is the author accepted manuscript. The final version is available from Springer via the DOI in this recordData Availability: All data and materials used in the research are documented within the manuscript.Climate change, energy transition, population growth and other natural and anthropogenic impacts, combined with outdated (unfashionable) infrastructure, can force Dam and Reservoir Systems (DRS) operation outside of the design envelope (adverse operating conditions). Since there is no easy way to redesign or upgrade the existing DRSs to mitigate against all the potential failure situations, Digital Twins (DT) of DRSs are required to assess system’s performance under various what-if scenarios. The current state of practice in failure modelling is that failures (system’s not performing at the expected level or not at all) are randomly created and implemented in simulation models. That approach helps in identifying the riskiest parts (subsystems) of the DRS (risk-based approach), but does not consider hazards leading to failures, their occurrence probabilities or subsystem failure exposure. To overcome these drawbacks, this paper presents a more realistic failure scenario generator based on a causal approach. Here, the novel failure simulation approach utilizes fuzzy logic reasoning to create DRS failures based on hazard severity and subsystems’ reliability. Combined with the system dynamics (SD) model this general failure simulation tool is designed to be used with any DRS. The potential of the proposed method is demonstrated using the Pirot DRS case study in Serbia over a 10-year simulation period. Results show that even occasional hazards (as for more than 97% of the simulation there were no hazards), combined with outdated infrastructure can reduce DRS performance by 50%, which can help in identifying possible “hidden” failure risks and support system maintenance prioritization.Science Fund of the Republic of SerbiaSerbian Ministry of Education, Science and Technological Developmen

Bidirectional Cardio-Respiratory Interactions in Heart Failure

We investigated cardio-respiratory coupling in patients with heart failure by quantification of bidirectional interactions between cardiac (RR intervals) and respiratory signals with complementary measures of time series analysis. Heart failure patients were divided into three groups of twenty, age and gender matched, subjects: with sinus rhythm (HF-Sin), with sinus rhythm and ventricular extrasystoles (HF-VES), and with permanent atrial fibrillation (HF-AF). We included patients with indication for implantation of implantable cardioverter defibrillator or cardiac resynchronization therapy device. ECG and respiratory signals were simultaneously acquired during 20 min in supine position at spontaneous breathing frequency in 20 healthy control subjects and in patients before device implantation. We used coherence, Granger causality and cross-sample entropy analysis as complementary measures of bidirectional interactions between RR intervals and respiratory rhythm. In heart failure patients with arrhythmias (HF-VES and HF-AF) there is no coherence between signals (p < 0.01), while in HF-Sin it is reduced (p < 0.05), compared with control subjects. In all heart failure groups causality between signals is diminished, but with significantly stronger causality of RR signal in respiratory signal in HF-VES. Cross-sample entropy analysis revealed the strongest synchrony between respiratory and RR signal in HF-VES group. Beside respiratory sinus arrhythmia there is another type of cardio-respiratory interaction based on the synchrony between cardiac and respiratory rhythm. Both of them are altered in heart failure patients. Respiratory sinus arrhythmia is reduced in HF-Sin patients and vanished in heart failure patients with arrhythmias. Contrary, in HF-Sin and HF-VES groups, synchrony increased, probably as consequence of some dominant neural compensatory mechanisms. The coupling of cardiac and respiratory rhythm in heart failure patients varies depending on the presence of atrial/ventricular arrhythmias and it could be revealed by complementary methods of time series analysis

Sinteza i karakterizacija semi-interpenetrirajućih mreža hitozana i poli(N-vinil-2-pirolidona)

Semi-interpenetrating networks (semi-IPNs) based on chitosan and poly(N-vinyl-2-pyrrolidone) were prepared in order to achieve better mechanical properties. The samples were characterized by FTIR, SEM, DMA analysis and the swelling behavior at different pHs (2.0-8.0). The semi- -IPNs composition was found to have a great impact on the hydrogel structure, mechanical properties, morphology and swelling kinetics. The gels demonstrated substantial change in buffer absorbency with the change of pH, high for acid buffers and lower for pH values above 6 where the swelling was considerably slow. Incorporation of PVP led to better mechanical strength of semi-IPNs while keeping a satisfactory degree of swelling, which makes them suitable for various applications.U ovom radu je prikazana sinteza i karakterizacija semi-IPM hitozana sa poli(N-vinil-2-pirolidonom) različitog sastava i stepena umreženja. FTIR analizom je utvrđeno da interakcije između hitozana i PVP-a potiču od amino grupa hitozana i karbonilnih grupa PVP. Utvrđeno je da semi-IPM imaju poroznu strukturu i da bubrenje zavisi od pH okolnog rastvora, koncentracije umreživača i sadržaja PVP-a. Dodatak PVP-a poboljšava mehanička svojstva, ali istovremeno zadržava zadovoljavajući stepen bubrenja što sintetisane semi-IPM čini pogodnim za primenu u raznim oblastima

The influence of thermodynamic state of mineral hydraulic oil on flow rate through radial clearance at zero overlap inside the hydraulic components

In control hydraulic components (servo valves, LS regulators, etc.) there is a need for precise mathematical description of fluid flow through radial clearances between the control piston and body of component at zero overlap, small valve opening and small lengths of overlap. Such a mathematical description would allow for a better dynamic analysis and stability analysis of hydraulic systems. The existing formulas in the literature do not take into account the change of the physical properties of the fluid with a change of thermodynamic state of the fluid to determine the flow rate through radial clearances in hydraulic components at zero overlap, a small opening, and a small overlap lengths, which leads to the formation of insufficiently precise mathematical models. In this paper model description of fluid flow through radial clearances at zero overlap is developed, taking into account the changes of physical properties of hydraulic fluid as a function of pressure and temperature. In addition, the experimental verification of the mathematical model is performed