bluuebunny/crossref_metadata_2025 huggingface dataset:
Mutual Coupling Reduction Using Electromagnetic Band Gap Structures
Authors: Gowri Chaduvula  , Leela kumari B
Published: December 2024

This paper introduces a novel technique to reduce mutual interference in antenna arrays. In a conventional antenna array, radiating elements placed on the same ground plane generate strong surface waves, which propagate through the ground plane and cause interference. When these radiating elements are closely spaced, strong mutual coupling occurs. This study involved designing a 1x2 patch antenna array on a FR-4 substrate with an edge-to-edge spacing of 0.2λ. To mitigate the effects of surface waves, a high-impedance surface was created using Electromagnetic Band Gap (EBG) structures. Incorporating Mushroom EBG (MEBG) unit cells with the antenna elements, mutual coupling was reduced by 2.3 dB, making the design suitable for wireless applications at 5.2 GHz. With the support of HFSS software, the proposed antenna array was designed and simulated.
“AI-Powered Earthquake Resilience: Predictive Modeling and Design Optimization for Seismic-Resistant Structures."
Authors: Mr. Abhijit S. Kolhe  , Dr. V.R. Rathi
Published: December 2024

The study introduces an AI-powered framework for predictive modeling and design optimization of seismic-resistant structures. It uses machine learning algorithms to analyze historical earthquake events, structural responses, and material properties. The framework integrates real-time data analytics, ensuring structural integrity and immediate response to seismic threats. Case studies show improvements in structural resilience, reduced damage, and cost-effectiveness.The increasing frequency and intensity of seismic events necessitate the development of advanced strategies for enhancing the resilience of structures. This study introduces an AI-powered framework aimed at predictive modeling and design optimization for seismic-resistant structures. By leveraging machine learning algorithms, the proposed methodology analyzes vast datasets of historical earthquake events, structural responses, and material properties to identify patterns and predict potential vulnerabilities in existing designs. The framework integrates real-time data analytics, enabling the continuous assessment of structural integrity and immediate response to seismic threats. Additionally, it employs generative design principles to optimize structural configurations, materials, and reinforcement strategies, ensuring compliance with contemporary building codes and enhancing performance during seismic activities. Case studies demonstrate the effectiveness of this approach, showcasing significant improvements in structural resilience, reduction in potential damage, and cost- effectiveness. Ultimately, this research contributes to the advancement of smart construction practices, promoting sustainable urban development in earthquake-prone regions and fostering safer communities.
Peran Kurikulum Merdeka dalam Meningkatkan Tingkat Literasi di Kota Malang
Authors: Muhammad Abi Hamzah  , Arieni Alfakhaera  , Slamet Daroini
Published: December 2024

Penelitian ini bertujuan untuk menilai kontribusi Kurikulum Merdeka dalam meningkatkan tingkat literasi di Kota Malang, dengan fokus pada aspek membaca, menulis, dan pemahaman teks. Selain itu, penelitian ini juga bertujuan untuk mengeksplorasi tantangan yang mungkin dihadapi dalam pengimplementasian kurikulum Merdeka dalam meningkatkan tingkat literasi di Indonesia, khususnya di Kota Malang. Penelitian ini menggunakan metode library research dengan mengumpulkan data dari berbagai sumber literatur yang relevan. Hasil penelitian menunjukkan bahwa Kurikulum Merdeka memiliki peran strategis dalam meningkatkan literasi siswa melalui pendekatan pembelajaran yang berfokus pada pengembangan keterampilan esensial, seperti literasi dasar, literasi digital, dan kemampuan berpikir kritis. Penerapan Kurikulum Merdeka di sekolah-sekolah di Kota Malang telah memberikan kontribusi positif dalam meningkatkan kemampuan literasi siswa. Namun, implementasinya masih menghadapi beberapa tantangan, seperti kurangnya pemahaman guru terhadap kurikulum, keterbatasan sumber daya dan infrastruktur, serta resistensi terhadap perubahan di kalangan tenaga pengajar. Simpulan dari penelitian ini adalah bahwa Kurikulum Merdeka memiliki peran penting dalam meningkatkan literasi di Kota Malang, namun memerlukan upaya yang lebih komprehensif dalam memberikan pelatihan bagi guru, meningkatkan sarana prasarana, dan memperkuat dukungan dari manajemen sekolah agar implementasinya dapat berjalan lebih efektif.
Kafa'ah Dalam Pernikahan: Relevansi Surat Al-hujurat Ayat 13 Di Era Society 5.0
Authors: Nabila Rihhadatul Aisy  , Nasrulloh Nasrulloh
Published: December 2024

Penelitian ini mengkaji pengertian kafa'ah dalam pernikahan yang merujuk pada surah Al-Hujurat ayat 13 dan signifikansinya dalam konteks Society 5.0. Dalam Islam, kafa'ah mencakup kesetaraan moral, spiritual, dan sosial, yang penting untuk membina keluarga yang damai. Meski demikian, kemajuan teknologi dan ilmu pengetahuan dalam konteks Society 5.0 menimbulkan kendala baru, khususnya bagi generasi muda yang memiliki cara pandang kafa'ah berbeda dibandingkan generasi sebelumnya. Penelitian ini menggunakan metodologi kualitatif dengan memanfaatkan teknik tinjauan pustaka untuk mengkaji gagasan kafa'ah dan penerapannya dalam beradaptasi dengan keadaan yang berkembang. Temuan penelitian menunjukkan bahwa integrasi kafa'ah yang harmonis antara nilai-nilai tradisional dan modernitas sangat penting untuk meningkatkan kesejahteraan rumah tangga di era digital. Hal ini berkaitan dengan tujuan Society 5.0, yang menggarisbawahi penggabungan teknologi dengan nilai-nilai kemanusiaan untuk memberdayakan pasangan muda dalam mengambil keputusan berdasarkan ajaran Islam.
Exploring the Shortage of Licensed Dental Practitioners in Northwestern Minnesota
Authors:   , Knutson Gretchen
Published: December 2024

Purpose. This phenomenological study aimed to explore a sense of community in the lived experiences of licensed dental practitioners in Northwestern Minnesota. This study intends to contribute to social change regarding the licensed dental practitioner shortage in Northwestern Minnesota by providing lived experiences of licensed dental practitioners with the aspiration of inspiring new strategies to recruit licensed dental practitioners into rural and remote communities.
Conceptual Framework. The Psychological Sense of Community theory was the framework selected to support this phenomenological study. The study intended to determine whether the Psychological Sense of Community contributed to licensed dental practitioners remaining in rural or remote areas of Northwestern Minnesota.
Methodology. This phenomenological study leveraged interviews with selected participants, focusing on the lived experiences of licensed dental practitioners practicing in Northwestern Minnesota. Interview data was gathered, collated, thoughtfully analyzed, and coded to identify common themes.
Findings and Conclusion. Three themes were revealed from data analysis: 1) the shortage of dental specialists and retirement impacts, 2) recruitment, community engagement, and barriers, and 3) collaboration opportunities. The results identified from
the study are associated with the primary research question and the study’s conceptual framework.
Recommendations. Future research could add to and strengthen the findings of this study by conducting a qualitative or mixed-method study with a larger participant group. Expanding the study to other rural or remote areas within the United States may be beneficial in uncovering similar conditions. Additional research might be beneficial in creating a universal approach to recruitment, retention, and incentive opportunities in rural and remote areas of the United States.
Self-Determination and Black Women Leaders
Authors: Turley Denise
Published: December 2024

This article presents a phenomenological study of the leadership experiences of Black women through the lens of self-determination theory. Self-determination theory (SDT) suggests people can grow and change when their needs for competence, connection, and autonomy are fulfilled; once those needs are met, people become self-determined (Ryan & Deci, 2017). The researcher designed this qualitative study on the conceptual framework of self-determination theory to understand the success factors associated with Black women. Semi-structured interviews were conducted with twelve Black women leaders living or working in Virginia. Three main themes emerged during data analysis corresponding with self-determination theory: (1) relatedness/support, (2) autonomy/authenticity, and (3) competence/confidence.
Clinical Mental Health Professionals’ Perception on Quality, Change, and the Industry Impact of Telecounseling
Authors: Boykin Whitney
Published: December 2024

On March 11, 2020, the World Health Organization declared the COVID-19 pandemic, which is currently ongoing and has social and health consequences for everyone (Sheridan et al., 2021). More than 90% of the United States population was under stay-at-home orders during spring 2020—telepsychology quickly grew to become the primary option for Americans in need of mental healthcare (Greenbaum, 2020). The United States Government demonstrated a commitment to developing, promoting, and integrating technology-assisted care in the United States by awarding $15 million to support telehealth providers during the COVID-19 pandemic (Health and Human Services, 2020). The specific problem to be addressed in this study is counselors’ lack of skills and knowledge in virtual counseling settings (Bernacchio & Wilson, 2018). The purpose of this phenomenological study is to gain knowledge of the experienced clinical mental health counselors’ perception of preparation experience for teletherapy with the intent of providing recommendations for professional organizations and counselor education programs regarding virtual counseling. Experiences of clinical mental health professionals who engage in distance counseling were explored to understand how a lack of training and resources affects clinical mental health counselors’ virtual counseling sessions with clients. Findings showed that counselors who were in the laggard category had difficulty adapting to change in the mental health industry, while the innovators, early adopters, and late majority excelled in virtual counseling.
Phenotypic segregation, penetrance, and expressivity of eye shape and wing shape in Drosophila melanogaster
Authors: Kleinsteuber Makenzie , Wu Yusheng
Published: December 2024

Drosophila melanogaster (fruit fly) is commonly used as a model organism because it has significant properties such as short life cycles, abundance in genetic variations, relative inexpensiveness, and small body size. Mendelian traits studied were bar eye (B), apterous body (ap), and vestigial body (vg). Two crosses, (Bar × apterous) and (Bar × vestigial), the corresponding F1 and F2 generations were created according to the mating map. The goodness of fit test for the observed data against the theoretical segregation ratios was analyzed using the χ2 statistical test. The results showed that the observed segregation ratios for males and females in both crosses didn’t fit the theoretical ratios because the χ2 values were much greater than the critical χ2 value (7.82) at a 5% significant level. The causes of the disagreement could be the gene interaction and the role of modifier genes. For the Bar gene, the male penetrance was complete for both crosses. The phenomenon was due to the hemizygote status of the gene. However, incomplete penetrance and variable expressivities were observed in females for both crosses. In Bar × apterous, when Bar was in homozygotic status, the penetrance was 12.5% under wild type background of wing shape and 0.0% under apterous body background. In the heterozygotic status, the variable expressivities were 41.8% of a round eye, 15.2% of a dent eye, and 30.5% of an oval eye with wild type wing allele, whereas 33.3% of a round eye and 66.7% of an oval with apterous allele respectively. There was no dent eye fly. In Bar × vestigial, the Bar gene in homozygotic status showed 17.8% and 7.7% penetrance under the background of wild-type and vestigial alleles in females. The variable expressivities exhibited 39.8% of a round eye, 17.5% of a dent eye, and 24.9% of an oval eye with wild type winged allele, whereas 30.8% of a round eye, 42.3% of dent eye, and 19.2% of an oval eye with vestigial allele respectively. The genetic study is still an effective way to investigate the gene interaction.
Effects of temperature on growth date, weight, and length of mutants of Drosophila melanogaster
Authors: Rocco Emma , Wu Yusheng
Published: December 2024

The fruit fly, Drosophila melanogaster, was chosen due to its small size, short life cycle, significant genetic variability, and relatively inexpensive to propagate. Little is known about the effects of temperature on the development of fruit fly mutants, including scarlet eye, vestigial wing, white eye, yellow body, and wild-type strains. This study aimed to explore the effects on dry weight and body length among those five strains at two different temperatures, 20°C and 25°C. The data was analyzed using the t-test, ANOVA, and Tukey HSD test. The observation records showed that temperature did affect the number of days in each growth period for all five strains. The high temperature (25°C) shortened those periods. The low temperature (20°C) prolonged those periods. The ANOVA and Tukey DSH test found the difference between the dry weight and body length pairs among those five strains at 20ºC and 25ºC. The t-test results demonstrate the difference in dry weight and body length between the two temperature settings in females and males of each strain.
A genetic study on eye shape, body color and eye color in Drosophila melanogaster
Authors: Salomon Kristen , Wu Yusheng
Published: December 2024

Drosophila melanogaster, the fruit fly, is an excellent organism for genetics studies because it has a short life span, produces large numbers of offspring, and has many types of hereditary variations that can be observed with low-power magnification. Mendelian traits studied were bar eye (B), scarlet eye color (st), and yellow body color (y). Two crosses, (bar × yellow) and (bar × scarlet), the corresponding F1 and F2 genera­tions were created according to the mating maps. The goodness of fit test for the observed data against the theoretical segregation ratios was analyzed using χ2 statistical test. The results showed that the observed segregation ratios for male and female in both crosses didn’t fit the theoretical ratios because the χ2 values were much greater than the critical χ2 value (7.82) at 5% significant level. The causes of the disagreement could be the gene interaction and the role of modifier genes. For Bar gene, the penetrance was complete in male for both crosses. This was due to the hemizygote status of the gene. However, the incomplete penetrance and variable expressivities were observed in female for both crosses. In bar × yellow, when Bar was in homozygotic status, the penetrance was 46.5% under wild type background of body color and 55.6% under yellow body color background. In the heterozygotic status, the variable expressivities were 47.1% dent eyes and 6.4% oval eyes with wild type allele, whereas 38.9% and 5.6% with yellow mutant. In bar × scarlet, the Bar gene in homozygotic status showed 64.2% and 10.5% penetrance under wild type allele and yellow allele. In heterozygotic status, the variable expressivities appeared 22.0% dent eye and 13.8% oval eye with wild type background, whereas 79.0% and 10.5% with scarlet allele respectively. The genetic study is still an effective way to investigate the gene interaction.
Enhancing Fake News Detection with a Hybrid NLP-Machine Learning Framework
Authors: Nadeem Muhammad , Abbas Parchamdar , Zhang Wei , Rafique Sumaira , Iqbal Sundas
Published: December 2024

The increasing prevalence of fake news on social media has become a significant challenge in today’s digital landscape. This paper proposes a hybrid framework for fake news detection, combining Natural Language Processing (NLP) techniques and machine learning algorithms. Using Term Frequency-Inverse Document Frequency (TF-IDF) for feature extraction, and classifiers such as Logistic Regression (LR), Naïve Bayes (NB), and Support Vector Machines (SVM), the model integrates Maximum Likelihood Estimation (MLE) with Logistic Regression to achieve 95% accuracy and 93% precision on a Kaggle dataset. The results highlight the potential of combining statistical and NLP approaches to improve fake news detection accuracy.
VARIABILITY OF ACTIVE GALACTIC NUCLEI
Authors: Kollatschny Wolfram , W. Ochmann Martin , A. Probst Malte
Published: December 2024

Abstract. All active galactic nuclei (Seyfert 1 galaxies, quasars) are variable in the con- tinuum flux. Furthermore, their broad emission lines vary as well on time scales of weeks to years. First, we will present the results of variability campaigns on two prototype AGN. Then we will show what we can learn from the variability about the geometry and kinemat- ics in the innermost regions that are surrounding the central supermassive black holes. The second part is dedicated to galaxies that show extreme variations in their spectral profiles - the so-called changing look AGN.
BAIKAL-GVD NEUTRINO TELESCOPE: UNLOCKING THE SECRETS OF THE UNIVERSE'S CATASTROPHIC EVENTS
Authors: A. Allakhverdyan V. , V. Naumov D. , I. Zavyalov S.
Published: December 2024

Abstract. We briefly review state-of-the-art in neutrino astronomy, a new rapidly evolv- ing branch of multi-messenger astronomy, paying more attention to status of Baikal-GVD neutrino telescope, its commissioning, simulation, data analysis and major results.
BARYONIC MASS IN NEARBY GALAXIES (PHD THESIS)
Authors: Jovanović Milena
Published: December 2024

Abstract. In my doctoral research, I utilized high-resolution observations from the HI Nearby Galaxy Survey (THINGS) to model the dynamical and baryonic mass distributions of nearby galaxies. These observations of neutral atomic hydrogen, boasting extensive data, enabled us to extract the rotation curve, thereby deducing the total dynamical mass up to a significant radius. In conjunction with infrared observations, we concurrently fit the dynamical mass with the observed stellar mass, the neutral gas component, and various dark matter (DM) models. The stellar mass was adjusted using the mass-to-light ratio, a critical factor in our study. We describe the DM component within the ΛCDM framework, using two distinct profiles: the pseudo-isothermal sphere and Navarro-Frenk-White. With the values for dynamical, stellar, gas, and dark matter mass determined, we derived assorted mass functions and distribution functions for our sample. From all the distribution functions we only present and discuss the distribution of the mass-to-light (M/L) ratio in detail here. The parameter is crucial for calculation of baryonic mass since it connects the observable quantities with the stellar (and consequently baryonic) mass required by dynamical models.
IDENTIFICATION OF POTENTIAL RED NOVA PROGENITORS
Authors: Wadhwa Surjit
Published: December 2024

Abstract. Luminous red novae are rare transient events thought to be the result of the merger of contact binary system components into a single star. So far, there is only one confirmed observed event, that of V1309 Sco (Nova Sco 2008). Unfortunately, that system was recognized as a contact binary only after the merger event, so targeted observations to fully elucidate the properties of the components and events leading up to the merger itself could not be performed. With ever increasing number of identified contact binary systems from sky surveys there is heightened interest in the identification of red nova progenitors. We have developed and are refining methods and relationships linking geometric parameters obtained through light curve analysis and the mass of the primary component with orbital instability. We discuss some theoretical and practical application of the new relationships to a group of poorly studied contact binary systems. In addition, we briefly touch on the effects of stellar composition on contact binary orbital stability.
POSSIBLE EFFECTS OF MAGNETIC ACTIVITY IN ORBITAL LIGHT CURVES OF CLOSE BINARIES
Authors: Garcés Letelier Juan , E. Mennickent Ronald , Petrović Jelena
Published: December 2024

Abstract. In close binary systems with magnetic activity in at least one of their com- ponents, distinctive features can be observed in their light curves. This study presents a photometric analysis of several binary systems with at least one active component. We start with a preliminary study of the O’Connell effect in short orbital period binaries identified in the Kepler binary catalog. This phenomenon in the light curves could be attributed to the migration of spots on the surface of the active star, making them key objects for studying the differences between the magnetic fields of isolated stars and those in binary systems. In addition, a comprehensive photometric analysis could reveal unexpected behaviour in the orbital light curves, related to magnetic activity. Recently, we have analysed the light curves of Double Periodic Variables binary systems and found cyclic changes in their orbital light curves, possibly as a consequence of a magnetic dynamo operating in the donor star. These results open up new perspectives for exploring the consequences of stellar magnetism in interacting binaries.
SPECTRAL CHARACTERISTICS OF FAST ROTATING METAL-POOR MASSIVE STARS
Authors: Kubátová Brankica , Szécsi Dorottya
Published: December 2024

Abstract. Low-metallicity massive stars are assumed to be progenitors of certain supernovae, gamma-ray bursts, and gravitational wave emitting mergers. These exotic phenomena contribute to their host galaxies through strong ionizing radiation and mechanical feedback. Here we investigate a certain type of very metal-poor (0.02 xxx Z xxx 0) hot massive single stars that rotate fast and evolve chemically homogeneously. Combining state-of-the-art theories of stellar evolution and stellar atmospheres modelling we predict synthetic spectra of these stars corresponding to different masses and evolutionary phases. The predicted spectra in early evolutionary phases is classified mainly as an early-O type giant or supergiant while in later evolutionary phases most of our model spectra are assigned to the WO-type spectral class. The Hubble Space Telescope’s (HST) Ultraviolet Legacy Library of Young Stars as Essential Standards (ULLYSES) program will enable us to compare our predicted spectra with observations of stars of similar nature (e.g., metal-poor stars in Sextant A).
WE CAN SPREAD OUR GENETIC MATERIAL
Authors: V. Lukić Dragan
Published: December 2024

Abstract. Despite our inability to send humans to the stars we still can send our Earth genetic material toward them, with small chance it will reach exoplanets around them. Our chance is embedding interstellar objects (ISO) which constantly trespass our Solar system with samples of organisms which can withstand long cry-preservation. New researches in biology return promising results. If the number density estimates based on the discovery of two ISOs are even approximately correct, there should be a number of ISO in the solar system at any one time. Future sky surveys should start finding a regular stream of 1I- type ISOs. 2I-type interstellar comets appear to be much rarer, and will probably be a decadal phenomena. A long term program to find and visit ISOs can start now with existing technology. Recently it is demonstrated that a mission to Oumuamua would be feasible, even without Solar Oberth Maneuver, and could be used to explore ISOs. New technology and new instruments will be required to best find passing ISOs, and also crucial development of technology for safely embedding. We will disscuse chance of life samples to survive flight to other stellar system.
LARGEST ASTRONOMICAL OPTICAL TELESCOPES
Authors: Jankov Slobodan
Published: December 2024

Abstract. A review of the largest astronomical optical telescopes which are presently operational or under construction is presented. Their scientific capabilities are described briefly, particularly with respect to astrophysical spectroscopy and interferometry.
DEVELOPMENT OF A MULTIFUNCTIONAL INSTRUMENT FOR THE 1.4m MILANKOVIĆ TELESCOPE
Authors: Vince Oliver , Pančić L. , V. Moiseev A. , S. Shablovinskaya E. , Č. Popović Luka , Vukotić Branislav , Ilić Dragana , N. Dodonov S. , Naumović N.
Published: December 2024

Abstract. In this work, we present an idea for the construction of a multifunctional device for the 1.4m Milanković telescope at the Astronomical Station Vidojevica. The device would be optimized to operate in three modes - low resolution spectroscopy, image polarization and photometry. This work is a collaborative project of astronomers in Astronomical observatory of Belgrade (AOB) and the Special Astronomical Observatory of the Russian Academy of Sciences (SAO RAS), which has a long history in designing and building similar instruments. We will present the main idea of the project and the possible technical solution of the device that is optimal for the Milanković telescope.
KINEMATICS OF TYPE II CEPHEID PULSATING STARS
Authors: Stojanović Milan , Jurković Monika , Ninković Slobodan
Published: December 2024

Abstract. In the GAIA Data Release 3 catalogue, published in 2023, there are 15021 stars classified as Cepheids. We will use a sub-sample of stars classified as Type II Cepheids (T2C) from the GAIA catalogue that have all the necessary parameters (full astrometry and radial velocity) to calculate the galactocentric orbits of these stars. For this we will use the analytical potential proposed earlier by one of the authors. We will calculate angular momentum and energy of the stars to determine if they belong to some of the known mergers, as it has been shown that satellite galaxies of the Milky Way can be considered as particles with very similar integrals of motion. We will analyse the distribution of the energy and angular momentum for our sample of stars. It is very likely that most of the T2Cs were created in the Milky Way however, there is a subgroup of T2Cs that have significantly different metallicities than the other stars. This could be an indication that they might have originated from different surroundings, such as a different galaxy, and came to the Milky Way via a merger event. In this work we will examine this possibility.
TEN YEARS OF MONITORING OF 1722+119 AT ASTRONOMICAL STATION VIDOJEVICA
Authors: D. Jovanović Miljana , Damljanović Goran
Published: December 2024

Abstract. In 2011, two years before the launch of the Gaia satellite, 47 objects for the link between the future Gaia Celestial Reference Frame and International Celestial Reference Frame were proposed. We have been actively observing these 47 objects at the Astronomical Station Vidojevica since 2013. These objects are Active Galactic Nuclei and the monitoring of their brightness is important in order to investigate the physical processes which can affect their astrometric precision. The observations were performed mostly in V and R bands,and occasionally in B and I bands. Here, we present the photometry results, analysis of brightness, and V − R colour using 10 years of observations of the object 1722+119 (the most variable source in our list of objects).
ASTRONOMY EDUCATION IN SERBIA 2020-2023
Authors: Vučetić Milica , Ilić Dragana , Arbutina Bojan , Jurković Monika , Kovačević-Dojčinović Jelena , S. Pavlović Marina , Milošević Stanislav , Stojičić Biljana , Prodanović Tijana , Cvetković Zorica
Published: December 2024

Abstract. Within this contribution we aim to present a review of triennial activities in astronomy education in Serbia at all levels: the astronomy education at the universities in Serbia, especially the activities at the University of Belgrade - Faculty of Mathematics, Department of Astronomy; the astronomy education within secondary schools and the activ- ities of the Society of Astronomers of Serbia in astronomy education, such as the teacher’s training, organized by the IAU NAEC Serbia.
NAUČNI RAD VJAČESLAVA ŽARDECKOG I SARADNJA SA MILUTINOM MILANKOVIĆEM
Authors: Todorović Nedeljko , Janc Natalija , Gavrilov Milivoj
Published: December 2024

Abstract. Vjačeslav Žardecki (Odesa 1896 - Elkins, SAD, 1962) je posle studija i specijalizacije iz astrofizike kraće vreme radio u Opservatoriji u Odesi i Pulkovskoj opservatoriji u Petrogradu (Rusija). Kada se 1920. godine doselio u Beograd, zaposlio se kao asistent na Astronomskoj i meteorološkoj opservatoriji. Kasnije je nastavio univerzitetsku karijeru na Univerzitetima u Beogradu, Austriji i Sjedinjenim Američkim DrŽavama. Glavna polja
istraŽivanja Žardeckog su bila hidromehanika, astrofizika, geofizika i racionalna mehanika, iz kojih je objavio značajne naučne radove i monografije. Neki od njegovih radova su inspirisani Milankovićevom teorijom o klimatskim promenama i rezultatima predstavljenim u njegovom "Kanonu".
Od dolaska u Beograd, Vjačeslav Žardecki je imao uspešnu naučnu saradnju sa Milutinom Milankovićem (Dalj, 1879 - Beograd, 1958). Milanković mu je bio u komisiji prilikom odbrane doktorata, a zatim se saradnja nastavila i tokom Milankovićevog najplodnijeg perioda, o čemu svedoči i prepiska Milankovića sa kolegama iz inostranstva, gde Žardeckog naziva "vernim saradnikom". Za vreme boravka Žardeckog u Jugoslaviji, Austriji i SAD, ova dva naučnika su se redovno dopisivala, a pisma se čuvaju u arhivi SANU u Beogradu.
ASTRONOMY EDUCATION THROUGH DIGITAL MEDIA
Authors: S. Pavlović Marina , Ilić Dragana , Kovačević-Dojčinović Jelena , M. Vučetić Milica , I. Jurković Monika
Published: December 2024

Abstract. In order to bring astronomical content to pupils all across Serbia, which is not part of regular school curricula, and to increase their interest in astronomy, we organized an astrophotography contest called ”Take a Photo of the night sky”. The contest was intended for primary and high school pupils, whom we invited to submit one photo taken with a mobile device in teams of no more than 5 pupils, under the supervision of a teacher. As part of the contest, professional training was organized for registered teams on how to make successful astrophotography using a mobile device (phone or tablet). A total of 184 teams from all over Serbia participated in the astrophotography contest, including more than 1,400 pupils and 200 teachers from all over the country. The astrophotography contest was organized by NAEC (National Astronomy Education Coordinators, representing the International Astronomical Union’s office of Astronomy for Education) Team Serbia with the great support of four major astronomical institutions in Serbia: the Society of Astronomers of Serbia, the University of Belgrade - Faculty of Mathematics, the Astronomical Observatory in Belgrade, the Mathematical Institute of the Serbian Academy of Sciences and Arts.
NEW EVENTS IN THE ASTRONOMICAL SOCIETY "RUDJER BOŠKOVIĆ"
Authors: Rovčanin Branislav
Published: December 2024

Abstract. Astronomical society “Rudjer Bošković” is the oldest society in the territory of the former Yugoslavia, whose main goal is the popularization of astronomy. Since its foundation, it has relied on input from enthusiasts as well as professional astronomers. The merits of the Belgrade Astronomical Observatory and its employees for the work of the society are immeasurable from the foundation of the society until the present day. Of particular importance is the society’s magazine “Vasiona”, which over several decades informs the general public about news in astronomy, as well as about events in society. In addition to the improvement of the workspace of the Public observatory and the Planetarium, a complete reconstruction of the Zeiss refractor, as well as other astronomical instruments and objects significant for the history of the society, was recently carried out. New observational methods were introduced, such as CCD astrophotography, spectrometry and photometry. Computer capabilities for processing observations have been improved, access to star catalogs has been made possible, and in the near future the process of automating the operation of the telescope will be completed. The first results of observation, some of which have been published, also came from these methods. “Vasiona” magazine has continued to be published after a significant break, and educational courses and thematic gatherings are going on smoothly. In the coming period, the improvement of spatial and working conditions will be continued, as well as the preservation of cooperation with professional astronomers and motivated individuals with the aim of sustainable progress and preservation of the achievements of society.
PROJECT OF FIRST URBAN ASTRONOMICAL OBSERVATORY IN KRUŠEVAC
Authors: Tomić Zoran , Stanković Miloš , Mitrović Jelena , Gajić Jelena
Published: December 2024

Abstract. Since 2010, the astronomical society ”Eureka” has been actively working on the promotion of astronomy in Kruševac and Serbia. It carries out numerous activities, among which, in addition to citizen science projects and lectures, are astronomical observations.In 2022, the society managed to accomplish the most important project since its founding, which is the construction of the ”Šarengrad” astronomical observatory in the area of the ”Šarengrad” amusement park. An year of work has passed since its opening, which is anexcellent opportunity for analysis and further improvement of the work. In this paper, weshall present the results of our work in the past year including the citizen science projects and promotion of astronomy in general, along with the brief description of the project that led to the build-up of the first urban observatory in Kruševac with its implementation.
ASTRONOMICAL STATION VIDOJEVICA: OBSERVATIONS FROM 2011 TO 2023
Authors: Samurović Srdjan , Cvetković Zorica , Pavlović Rade
Published: December 2024

Abstract. We present the statistic of observing time used at the Astronomical Station Vidojevica (ASV) from its opening in 2011 to the current year. We analyze separately the first period, 2011-2018, when only the Nedeljković telescope (0.60 m) was available and the second period, 2018-2023, when also observations with the Milanković telescope (1.40 m) were performed. The year 2018 marks the beginning of public calls for observing time at the ASV and the reviewing of the received observational proposals by the Time Allocation Committee (TAC). Finally, we briefly analyze the scientific output produced using the telescopes mounted at the ASV, i.e., the number of printed papers in scientific journals in the 2011-2023 period.
DYNAMICS OF DUAL MASSIVE BLACK HOLE SYSTEMS FORMATION IN COSMOLOGICAL SIMULATIONS
Authors: Savić Sara , Smole Majda , Mićić Miroslav , Mitrašinović Ana , Milošević Stanislav
Published: December 2024

Abstract. Due to hierarchical evolution of galaxies and the fact that almost all massive galaxies have supermassive black hole (SMBH) in their center, galaxy mergers lead to forma- tion of dual SMBH systems or supermassive binary black holes (SMBBH). In order to better understand how properties of SMBBH depend on properties of merging galaxies, we inves- tigate these systems, circumstances of their formation and activity using the results from cosmological simulation IllustrisTNG300. We find that major mergers of gas rich galaxies are the main reason for formation of dual AGNs, with tendency to form more luminous AGNs.
SPECTRAL INDEX VARIABILITY OF 12 BLAZARS
Authors: D. Jovanović Miljana , Damljanović Goran
Published: December 2024

Abstract. We present the results from the spectral index variability analysis for a sample of 12 newly discovered blazars. The blazars are selected from the sample of 47 Active Galac- tic Nuclei suggested for the link between Gaia Celestial Reference Frame and International Celestial Reference Frame. Blazars flux and spectra are highly variable in the whole electro- magnetic spectrum. The amplitude of variability could depend on a number of parameters, including luminosity and spectral properties of the source. We tested optical spectral index for variability, to see if there is any correlation with the flux variability. For two sources 0049+003 and 1612+378 spectral index variability is detected. Both sources are flat spec- trum radio quasars, and have confirmed flux variability. For the other sources we did not find correlations between their flux and spectral index variability.
STUDY OF NGC4473: DOUBLE-SIGMA GALAXY
Authors: Lalović Ana , Knežević Sladjana
Published: December 2024

Abstract. With the advent of IFU observations (SAURON survey, followed by ATLAS3D survey) our picture of early-type galaxies that were thought to be monotonous (round, red, and dead) has changed dramatically. Early-type galaxies with two symmetric peaks in their velocity dispersion maps are dubbed double-sigma galaxies. One prototypical case is the NGC 4473 galaxy which is studied in this contribution using 3D spectroscopy that enabled detailed study of galaxy kinematics, age, and metallicity. Both spectroscopically and photometrically we decomposed the galaxy into three distinct components: one large de Vaucouleurs component and two smaller components counter-rotating compared to the large component. Large de Vaucouleurs component is dynamically hot while inner smaller struc- tures are dynamically cold suggesting that numerous minor, gas-rich mergers are responsible for its formation scenario.
БЕОГРАДСКА ОПСЕРВАТОРИЈА У ПЕРИОДУ 1887-1924
Authors: Нинковић С. , Мијатовић В.
Published: December 2024

The subject concerns the first phase in the development of the Astronomical Observatory in Belgrade, the time when it was part of a complex observatory – known as Observatory of Grand School (University from 1905) – at which in addition to astronomy some geosciences were included. The date (day and month), according to the Gregorian calendar, when that Observatory was founded is celebrated as the day of the present-day Astronomical Observatory in Belgrade.
ПОДЕЛА ЦЕНТРАЛНЕ АСТРОНОМСКЕ И МЕТЕОРОЛОШКЕ ОПСЕРВАТОРИЈЕ
Authors: С. Димитријевић М.
Published: December 2024

The division of the Belgrade Observatory into Astronomical and Meteorological ones in 1924 and its development and activities within the period 1924-1941 was discussed.
АСТРОНОМСКА ОПСЕРВАТОРИЈА У РАТНИМ ВРЕМЕНИМА
Authors: Јанц Н. , Ч. Поповић Л.
Published: December 2024

In this study we discuss several wars, with respect to their repercussive influence on the work of the Astronomical Observatory in Belgrade. From its inception in 1887, the Observatory has always actively participated in all social events in Serbia that are pertinent to or reflective of its work and development, even during periods of war. In this paper, we present the periods during both the First and Second World Wars, as well as during the 1999 NATO aggression that also left its mark on the Observatory.
АСТРОНОМСКА ОПСЕРВАТОРИЈА ПОСЛЕ ДРУГОГ СВЕТСКОГ РАТА ДО ДАНАС
Authors: Самуровић С. , Цветковић З.
Published: December 2024

In this paper we present the work of the Astronomical Observatory of Belgrade in the period after the Second World War until today. A chronology of the most important dates in the post-war history of the Observatory is given. The departments active at the Observatory are presented and their work is briefly described, as well as the recently established research groups at the Astronomical Observatory. The publishing activity of the Observatory in the mentioned period is briefly described. The most important works on the renovation of the facilities at the Observatory are also listed and the Collection of the Astronomical Observatory is briefly described. The activities related to the Astronomical Station Vidojevica and the instruments mounted there are described.
ЂОРЂЕ СТАНОЈЕВИЋ И АСТРОНОМСКА ОПСЕРВАТОРИЈА
Authors: С. Димитријевић М.
Published: December 2024

The life and work of Djordje Stanojević, the second head of the Astronomical and Meteorological Observatory, is described and his actions as the leader of this institution are discussed.
СТАЗОМ СЕЋАЊА - ПРОМЕНА КУЛТУРНОГ ПЕЈЗАЖА ОД ЦАРИГРАДСКОГ ДРУМА ДО КОТЕ 253
Authors: Радовановић Д.
Published: December 2024

: The paper discusses the redefinition of spatial relations in an effort to more precisely depict the placement of cultural patterns in a certain period of time, the idea of the city as a special concept and everyday life, that is, historical inertia.
ПОМРАЧЕЊЕ СУНЦА У КИКИНДИ
Authors: Вуца П.
Published: December 2024

The paper shows the activities in Kikinda on the occasion of the total eclipse of the Sun on August 11, 1999. The work is enriched with a lot of photographs, which show how the population prepared to observe this rare natural phenomenon.
ДАНИ ОТВОРЕНИХ ВРАТА НА АСТРОНОМСКОЈ ОПСЕРВАТОРИЈИ У БЕОГРАДУ
Authors: Мијатовић В. , Миловановић Н.
Published: December 2024

In this paper, we provide an overview of citizen visits to the Astronomical Observatory in Belgrade from the beginning of the Observatory's work at Zvezdara (1932) to the present day.
Earth’s Lower Ionosphere impacted by High Class X-Ray Solar Flare Events
Authors: Kolarski A.
Published: December 2024

AbstractSolar activity, especially with its energetic events like solar flares and coronal mass ejections of high intensity, triggers abrupt and strong disturbances within near Earth surroundings, posing the potential hazard to numerous sophisticated technological systems both space-borne and ground-based on one hand, and putting at risk all living life on our planet on the other. Direct influences of events like geomagnetic storms and solar flares on human health were reported in literature. In this paper effects of high class X-ray solar flares form descending branch of 24th solar cycle were analyzed in terms of associated mid-latitudinal lower ionospheric disturbances over European sector, based on simultaneously monitored Very Low Frequency signals’ perturbations as recorded by ground-based receiving system located in Belgrade, Serbia. Conducted numerical simulations revealed electron density increases of several orders of magnitude during maximal impact of analyzed solar flare events. - FULL TEXT available in PDF.
Study of very thin crystals by rainbow scattering effect
Authors: Starčević N. , Petrović S.
Published: December 2024

AbstractThis research introduces an innovative methodology for the analysis of very thin crystals, utilizing the rainbow scattering, a technique previously unexploited for this application. The focus is on assessing the capabilities of this method for an in-depth investigation of crystalline structures. To characterize the very thin crystals, we implemented numerical simulation techniques to model and evaluate rainbow scattering phenomena under channeling conditions. The simulations aimed to forecast the scattering patterns of protons as they traversed various cubic crystal types at different orientations. We identified distinct patterns of rainbow scattering, providing essential insights into the internal configurations and orientations of the cubic crystals examined. The combination of channeling mode rainbow scattering with numerical simulations presents a fresh and efficient approach for analyzing very thin crystals, setting the stage for subsequent experimental investigations. This advancement holds considerable promise for enhancing research in the fields of materials science and nanotechnology. - FULL TEXT available in PDF.
Implications of the Temperature Effect Analysis Using Simulated Secondary Cosmic Muon Data
Authors: Savić M.R. , Veselinović N.B. , Dragić A.L. , Maletić D.M. , Joković D.R. , Banjanac R.M. , Knežević D. , Travar M. , Udovičić V.I.
Published: December 2024

As it propagates through the atmosphere, the muon component of secondary cosmic rays is influenced by variations in atmospheric parameters. The two most significant atmospheric effects affecting the muon flux detected at ground level are the barometric effect, due to changes in atmospheric pressure, and the temperature effect, caused by fluctuations in atmospheric temperature.To enhance the sensitivity of ground-based muon detectors to cosmic ray variations of non-atmospheric origin, these effects must be corrected, with the temperature effect being more complex to model. The most well-established method for correcting the temperature effect is the integral method, based on the theory of atmospheric effects (Dorman 2004). However, as it is not so straightforward to implement, several empirical methods have been developed over the years, including the effective level of generation method (Duperier 1949), the mass-averaged temperature method (Dvornikov et al. 1976), as well as more recent approaches based on principal component analysis (Savić et al. 2019) and machine learning applications (Savić et al. 2021).Each theoretical and empirical approach has its advantages and limitations, and directly comparing the effectiveness of these methods with real measured data is not necessarily simple. One way to address this is to test model performance on simulated data, where atmospheric variation is the only source of flux change. Preliminary results from data simulated with the CORSIKA package (Heck et al. 1998) provide a clearer picture of the strengths and limitations of these methods. Specifically, the results suggest that the integral method may lead to overcorrections if applied too directly, an issue that hadn’t been that obvious before. - FULL TEXT available in PDF.
New molecular dataset for planet formation chemistry and modeling
Authors: Srećković V.A. , Pop N. , Vujčić V. , Dimitrijević M.S. , Christova M.D. , Mijić Z.
Published: December 2024

Detailed astrochemical models are essential for interpreting observations of interstellar and circumstellar molecules because they allow important physical features of the gas and its evolutionary history to be derived (Williams and Cieza 2011). Advances in astrochemical models are linked to changes in astrochemical databases, as well as experimental and theoretical estimations of rate coefficients (see e.g. Öberg et al. 2021). The science community now need access to such molecular data, including preferred ones, for further modeling, and it is critical to our knowledge of the chemistry of planet formation. As a result, atomic and molecular datasets and databases (such as VAMDC) have become critical for constructing models and simulations (see Albert et al. 2021 and references therein). The analysis of the studied rates provides valuable information on the presence of species. As a result, it is critical to investigate not only radiative processes, but also concurrent processes involving molecular ions, such as dissociative recombination (Kamp et al., 2017). Our goal is to calculate, compare, and analyze cross sections and rate coefficients for molecular ions such as hydrogen and helium for a various model parameters. - FULL TEXT available in PDF.
Machine Learning Classification Difficulties of VLF Amplitude Variations Around the Terminator
Authors: Arnaut F. , Kolarski A. , Langović M. , Srećković V.A. , Jevremović S.
Published: December 2024

Previously, very low frequency (VLF) ionospheric amplitude data was employed in various machine learning (ML) classification efforts (Arnaut, Kolarski, 2023; Arnaut et al., 2023; Arnaut et al., 2024), where the problem was defined as a binary classification task, determining whether a given data point in the test dataset was anomalous (e.g., solar flare events, instrument errors, nighttime signals, outliers) or a normal daytime signal. In a multiclass classification problem, each class must be clearly defined to prevent overlap and minimize the risk of false positives and/or false negatives. The analysis for this brief communication displays that the challenges in classifying nighttime versus daytime VLF amplitude signals occur at the terminator, a transitional zone between daytime-nighttime and nighttime-daytime signals. The majority of false positives and/or false negatives occur in this zone. Possible strategies for enhancing predictive power in this area may include statistical techniques such as cluster analysis or other methods that can be employed post-classification to further augment the overall efficacy of the approach. - FULL TEXT available in PDF.