bluuebunny/crossref_metadata_2025 huggingface dataset:
Predicting Team Advancement in Major League Baseball Postseason Using Borda Count
Authors: Chen Chih-Cheng , Kuo Tian-Shaing , Hung Kuang-Tsan , Wang Jung-Chang , Chen Ming-Yao , Tsai Chung-Yu
Published: November 2024

The prediction of sports competition outcomes has long been a topic of interest in academia and among sports enthusiasts. This study focuses on Major League Baseball (MLB) as its research subject, encompassing the years 2020, 2021, and 2022. By employing a set of established evaluation criteria, comprising five pitching and five hitting indicators from previous literature, the regular-season performance of the 30 MLB teams across both leagues (National League and American League) over the three-year period was compiled. Subsequently, a data normalization technique combined with the Borda count concept was proposed to develop a model for forecasting team advancement in the postseason. The predictive accuracy of the model presented in this study for determining MLB postseason qualifiers from 2020 to 2022 fell within the range of 55.6% to 66.7%, akin to models utilizing extensive datasets. Notably, the proposed model is more comprehensible and user-friendly, offering ease of understanding and application for sports enthusiasts and facilitating its potential utilization and dissemination in the sporting community.
Fixed-Ratio Approximation Algorithm for the Minimum Cost Cover of a Digraph by Bounded Number of Cycles
Authors: Khachai Daniil , Neznakhina Katherine , Rizhenko Ksenia , Khachay Michael
Published: November 2024

We consider polynomial time approximation for the minimum cost cycle cover problem of an edge-weighted digraph, where feasible covers are restricted to have at most k disjoint cycles. In the literature this problem is referred to as Min-k-SCCP. The problem is closely related to classic Traveling Salesman Problem (TSP) and Vehicle Routing Problem (VRP) and has many important applications in algorithms design and operations research. Unlike its unconstrained variant, the Min-k-SCCP is strongly NP-hard even on undirected graphs and remains intractable in very specific settings. For any metric, the problem can be approximated in polynomial time within ratio 2, while in fixed-dimensional Euclidean spaces it admits Polynomial Time Approximation Schemes (PTAS). In the same time, approximation of the more general asymmetric Min-k-SCCP still remains weakly studied. In this paper, we propose the first fixed-ratio approximation algorithm for this problem, which extends the recent breakthrough Svensson-Tarnawski-Vegh and Traub-Vygen results for the Asymmetric Traveling Salesman Problem.
Analisis Pengaruh Kualitas Website PPDB Online Terhadap Kepuasan Operator Sekolah Dasar (Studi Kasus Disdikpora Kab. Penajam Paser Utara)
Authors: Riyadi Hasan , Robertus Ila Bakho  , Joy Nashar Utamajaya
Published: November 2024

Penelitian ini bertujuan untuk mengetahui hubungan kepuasan kepala sekolah dasar dengan kualitas website PPDB online (menggunakan studi kasus Disdikpora Kabupaten Penajam Paser Utara). Penelitian ini menggunakan metodologi kuantitatif. Pemilik SD Disdikpora Kabi dijadikan sebagai subjek penelitian. Penajam Paser Utara mengambil sampel sebanyak 39 responden. Kuesioner digunakan dalam proses pengumpulan data. Metode pengujiannya meliputi uji analisis regresi yang menggabungkan temuan uji t, uji F, dan koefisien determinasi, serta uji validitas, uji reliabilitas, dan uji hipotesis tradisional. Berdasarkan temuan uji t, variabel kualitas kegunaan (X1) mempunyai pengaruh yang signifikan terhadap kepuasan administrator sekolah (Y) dengan nilai signifikansi sebesar 0,001. Nilai t estimasi sebesar 2739 menunjukkan bahwa nilai signifikansi kurang dari 0,05 dan nilai t lebih besar dari t tabel (2,739 > 2,026). Kepuasan pengelola sekolah (Y) secara parsial dipengaruhi oleh kualitas informasi (X2), dengan nilai thitung sebesar 2,913 dan nilai signifikansi sebesar 0,006. Oleh karena itu, nilai signifikansi t-tabel adalah (2,913). > 2,026 maka Ho ditolak dan Ha disetujui. Hasil uji F menunjukkan bahwa variabel kualitas informasi (X2) dan kualitas kegunaan (X1) mempunyai pengaruh secara simultan terhadap kepuasan administrator sekolah (Y). Memiliki estimasi F-value sebesar 52,017 dan nilai signifikansi sebesar 0,000. Oleh karena itu, karena nilai signifikansi F tabel (52,017 > 3,250), maka Ho ditolak dan Ha disetujui. Selain itu, nilai 0,729 atau 72,9% ditunjukkan oleh uji koefisien determinasi R2 terkoreksi (R-squared). Hal ini menunjukkan bahwa kualitas informasi (X2) dan kualitas kegunaan (X1) mempunyai pengaruh persentase sebesar 72,9% terhadap ukuran kepuasan administrator sekolah (Y). Faktor lain yang tidak termasuk dalam penelitian ini berdampak pada sisanya sebesar 27,1%.
Perancangan Aplikasi W-JAR sebagai Solusi Persiapan Ujian Kompetensi Keahlian Teknik Komputer Jaringan
Authors: Kurniasari Iin , Halimahtus Mukmina  , Ansori Mubarok
Published: November 2024

Sektor pendidikan merupakan salah satu sektor pembangunan yang sedang mendapat perhatian besar dari pemerintah dan sangat potensial untuk dapat diintegrasikan dengan kehadiran teknologi informasi. Salah satu sektor pendidikan yang berkembang sekarang ini adalah SMK (Sekolah Menegah Kejuruan). Dalam kelulusannya, SMK menerapkan Ujian Kompetensi Keahlian (UKK) yang merupakan langkah penjaminan mutu pendidikan dan kompetensi pada satuan pendidikan SMK. UKK berbentuk ujian praktik kejuruan wajib yang digunakan untuk mengukur kompetensi siswa selama menempuh pendidikan kejuruan sesuai bidang yang telah dipilih. Tidak sedikit siswa dan siswi SMK mengalami kesulitan dalam menghadapi Ujian Kompetensi Keahlian dikarenakan tidak mempunyai alat untuk mengulang belajar dirumah atau hanya paham materi namun di praktiknya kurang memahami dan kebanyakan persiapan UKK dilakukan dengan melakukan workshop atau praktik langsung di sekolah dalam waktu tertentu.
Berdasarkan momentum di atas, kami berinisiatif membuat Aplikasi yang bertujuan sebagai solusi alat bantu dalam persiapan Ujian Kompetensi Keahlian khususnya dalam Jurusan Teknik Komputer Jaringan. Aplikasi W-Jar diharapkan dapat  membantu siswa dalam mempersiapkan diri menghadapi UKK secara efektif dan efisien secara mandiri. Aplikasi ini menyediakan materi pelajaran, latihan soal, dan simulasi ujian yang sesuai dengan kurikulum dan standar kompetensi yang berlaku
Sentiment Analysis on Social Media using Bidirectional Encoder from Transformers (Case Study : Covid – 19 Omicron)
Authors: Pradipta Dody , Widodo Eko
Published: November 2024

Indonesia tercatat sebagai negara dengan jumlah pengguna internet terbesar di Dunia, sehingga adanya perubahan komunikasi dimasyarakat. Kemajuan jaman membuat interaksi manusia banyak dihabiskan pada media sosial, diantaranya Instagram, facebook, twitter (X) dan Tiktok mendominasi ruang digital. Tingginya interaksi pada sosial media, tidak bisa dipungkiri kerap kali bias, menimbulkan banyak persepsi baik karena subjektivitas, pandangan pribadi, maupun emosi sesaat. Pandemi Covid-19 memaksa pemerintah mencari solusi untuk berbagai masalah yang muncul, namun kebijakan yang diambil seringkali memicu gejolak di dunia maya. Penelitian ini bertujuan untuk melihat seberapa baik performa BERT dalam mengklasifikasikan komentar,  BERT (Bidirectional Encoder Representations from Transformers) memanfaatkan pendekatan word embedding untuk memahami konteks kata dalam dua arah. Arsitektur BERT menggunakan transformers, mekanisme yang memberikan makna kontekstual pada kata, membantu BERT dalam mengklasifikasikan komentar. Keunggulan BERT terletak pada pemahaman konteks kata yang mendalam melalui embedding kontekstual, dengan encoder transformers yang membaca kalimat dua arah.. Data yang digunakan adalah komentar pada instagram dan facebook didapatkan data sebanyak 3.522 data. Fokus penelitian ini adalah Covid – 19 varian omicron, topik ini diambil karena polaritas reaksi pada masyarakat. Model pada penelitian ini menggunakan 4 proporsional dataset, untuk melihat kontribusi data latih untuk model yang dikembangkan, sedangkan untuk evaluasi menggunakan dataset yang dilabeli secara manual. Penelitian ini mengungkapkan bahwa BERT dapat digunakan untuk mengklasifikasikan sentimen dengan hasil yang baik, model yang dibangun mendapatkan rentang efisiensi pada epoch 3 sampai 5, meskipun nilai terbaik berada epoch 8, dengan akurasi sebesar 90%. Mayoritas sentimen menunjukkan sentimen negatif ditengarai timbul panik dimasyarakat terkait penanganan Pandemi Covid – 19.
Concentration of Chemical Elements in Larix gmelinii Needles and Betula pendula Leaves
Authors:   Institute of Natural Resources, Ecology and Cryology of the Siberian Branch of the Russian Academy of Sciences, Makarov Vladimir P. , Zima Yurij V.
Published: November 2024

In the Trans-Baikal Territory, mining enterprises significantly pollute the environment with chemical elements. In these conditions, monitoring the state of the environment, including with the help of indicator plants, is of great importance. Among the woody plants, Gmelin larch (Larix gmelinii (Rupr.) Kuzen.) and silver birch (Betula pendula Roth.) are the most common in the region. Using the example of the Bystrinskoe Cu–Au–Fe skarnporphyry deposit, the concentrarion of 46 chemical elements in the needles of Gmelin larch and the leaves of silver birch, as well as the content of these elements in the soil, has been studied. The aim of the study is to identify plant species differences in the accumulation of elements and the prospect for using plants as indicators of environmental pollution. Scientific work has been carried out on 11 sample plots in natural plant communities near the enterprise’s facilities in August 2022. Soil and plant samples have been collected at the same time, at the same sites. The chemical analysis of the samples has been carried out using the “Methodology for measuring the metal content in solid objects by inductively coupled spectrometry” (FER 16.1:2.3:3.11–98). Differences in the concentration of elements in plants in relation to the clarke of terrestrial plants have been established. A statictically significant higher concentration of K, Ca, P, Mg, Fe, Ba, Zn, Na, Rb, Ni, Co, Ga, Sn, Y, Zr, Cd and Nb has been found in birch leaves compared to larch needles, and, conversely, a higher concentration of Sc, W and Hg – in larch needles than in birch leaves. Significant differences between plants have been established in the biological absorption coefficient of Se, P, Sn, Ca, Mn, Sr, Cd, Mg, K, W, Ni, Zn, Sc, Rb, Na and Nb. Knowledge about the peculiarities of accumulation of chemical elements in plant organs can be used for biomonitoring environmental pollution and, possibly, for phytoremediation of contaminated soils.
Adaptation of Pinus sylvestris Forms with Seeds of Different Colours under Conditions of Excessively Moist Soils
Authors:   N. Laverov Federal Center for Integrated Arctic Research of the Ural Branch of the Russian Academy of Sciences, Tarkhanov Sergei N. , Pinaevskaya Ekaterina A. , Aganina Yuliya E. , Pakhov Aleksandr S.
Published: November 2024

Adaptive changes in biochemical parameters of different pine forms under conditions of constant excessive soil moisture in the northern latitudes of the European part of Russia have been studied. The influence of seasonal variability on the dynamics of the photosynthetic pigment complex of pine forms with different seed colours has been shown. It has been established that elevated temperatures in early autumn contribute to the accumulation of chlorophyll, and this can negatively affect the hardening of trees in preparation for overwintering. The proportion of chlorophylls localized in the light-harvesting complexes of chloroplasts fluctuates from May to November from 43 to 60 %, which is associated with the adaptation of the photosynthetic apparatus of trees of different forms to the light conditions of high latitudes and other environmental factors. It has been determined that anthocyanins accumulate significantly more in pine needles in autumn, which increases their antioxidant role in this season. It has been revealed that peroxidase activity in 1-year-old needles increases in the autumn period. This can be considered as a protective reaction of different forms of pine, preventing the development of uncontrolled processes with a limited oxygen supply to the organs. A significant new formation of water-soluble proteins in pine needles with dark-coloured seeds has been detected due to the deterioration of weather conditions. This form, compared to pine with light seeds, probably reacts more strongly to the effect of stress factors that increase hypoxia of the root system. It has been concluded that the concentration of proline in needles is a very variable indicator, reacting sharply to the action of stress factors. No general trends in the seasonal dynamics of the indicator have been identified. It has been established that the content of ascorbic acid in the needles of trees of different forms of pine in late spring is significantly lower than in the summer and autumn seasons. This indicates the development of protective mechanisms to prevent oxidative stress under adverse weather conditions.
Digital Transformation of Small Businesses in Medan City
Authors: Sitorus Sunday Ade , Simanjuntak Sri Ida Royani , Sipayung Leonardo David , Simarmata Candra A.
Published: November 2024

This study aims to explore the effect of digital transformation on increasing e-commerce effectiveness through the mediating role of partnerships in small businesses in Medan City. This research focuses on digitalization strategies that can strengthen the competitiveness of small businesses in the digital economy era. The originality of the research lies in the quantitative approach that examines the relationship between digital transformation, partnership, and e-commerce effectiveness, which has not been widely studied in the context of small businesses in Medan. The research gap identified is the lack of understanding on how partnership can mediate the impact of digital transformation on e-commerce effectiveness. The method used was a quantitative survey with SEM-PLS technique to analyze data collected from 200 small business owners in 21 sub-districts in Medan. The research findings show that digital transformation has a significant influence on partnerships, but does not directly have a significant effect on e-commerce effectiveness. In addition, partnership does not have a significant mediating role between digital transformation and e-commerce effectiveness. The conclusion of this study is that small businesses in Medan need a more integrated digital strategy and adequate infrastructure support to improve e-commerce effectiveness through stronger partnerships.
Dimensi Budaya Hofstede dalam Komunikasi Antarkaryawan Organisasi Multinasional
Authors: Girsang Anastasia Putri Pearlyn , Murtiningsih Bertha Sri Eko , Astagini Nuria
Published: November 2024

The cultural differences within an organization can create various barriers in the communication process among employees. Therefore, with the increasing number of international migrants in Indonesia, employees are required to enhance their understanding of cross-cultural communication. One example is the marketing department employees of a multinational organization under the initial DO, which is led by two managers from different countries, Indonesia and Germany. Hence, this research aims to examine the communication practices of DO’s marketing department, which are influenced by two vastly contrasting cultures using Hofstede's cultural dimensions. To conduct the research, a descriptive case study method was used, employing in-depth interviews with five members of DO's marketing department. The research found that the dynamics of communication in the marketing department are greatly influenced by cultural dimensions, particularly in aspects such as decision-making and discussion processes, communication styles, task distribution patterns, freedom for innovation, employee work patterns, views on deadlines, and views on employee rights such as leave and dress code. The research also found that members of the department from Indonesia will only adopt foreign cultures brought by their expatriate leaders if they are deemed suitable or compatible with their own culture. Conversely, if they are not compatible, the German leader tends to accommodate and adjust to their other members. Understanding cultural dynamics that happens in communication among employees allows the company to detect types of communications that are happening and detect problems that might happen, for a more effective process.
Keywords: employee communication, Germany, Hofstede’s cultural dimensions, Indonesia, multinational organization
Strategi Komunikasi Lingkungan Ekowisata Taman Mangrove Jung Koneng Bangkalan untuk Rehabilitasi
Authors: Pratama Rafly Putra
Published: November 2024

Examining the environmental communication strategy implemented by the Payung Kuning Tourism Awareness Group as the manager of the Jung Koneng Mangrove Park in Labuhan Village, Ten District, Bangkalan. Starting from damage to the coastal environment due to the behavior of people who do not care about the sustainability of the mangrove ecosystem, as well as uncontrolled piles of rubbish, resulting in a significant decline in environmental quality. Using descriptive qualitative methods, researchers identified strategic steps in environmental communication which were grouped into four main stages, namely situation analysis, planning, media production, and action and reflection. At the situation analysis stage, Pokdarwis identified the environmental problems faced and the actors involved in mangrove rehabilitation. The planning stage involves developing a communication strategy based on local conditions, collaboration with external parties, and the use of traditional and digital media. In the media production stage, various communication channels such as social media, face-to-face discussions, and visual learning media are used to convey educational messages. The final stage, action and reflection, focuses on implementing rehabilitation activities and evaluating the impact of the communication strategies that have been implemented. Community participation not only contributes to the successful rehabilitation of the mangrove ecosystem, but also increases the community's social and economic awareness regarding ecotourism potential.
Keywords: environmental communication strategy, mangrove, ecotourism, education, Jung Koneng Mangrove Park
Konstruksi Realitas Sosial pada Cuti Melahirkan untuk Ayah dalam Undang-Undang No. 20 Tahun 2023
Authors: Pascarina Patrisia Amanda , Hartanto Louisa Christine , Putri Ranni Iqlima
Published: November 2024

Awareness of the role of the father, starting from the process of accompanying his wife giving birth to the process of caring for a newborn baby, has begun to be emphasized in modern society. This awareness then resulted in the Government Regulations Draft (RPP) regarding the management of State Civil Apparatus (ASN) as implementing regulations for Law number 20 of 2023 which will regulate paternity leave rights for male civil servants whose wives are about to give birth. So far, in Indonesia, both government and private institutions only regulate maternity leave for female employees. The social construction that has been formed is that women must take full responsibility in caring for newborn children. This research examines the perceptions of male civil servants and private employees regarding the draft law that will regulate paternity leave. Using Bless and Greifeneder's Social Cognitive Processing, 5 male civil servants and 5 male private employees were invited to participate in the FGD. This research shows that there are still misperceptions among male workers because of their thinking patterns which are still strongly derived from Indonesian patriarchal culture. Even though there are many facts in the form of research results about the role of fathers in childcare, male workers are still dominated by the perception that only women are responsible for childcare. Paternity leave does not need to be long because it can reduce men's productivity in the workplace. In fact, husbands’ presence is not only needed to help the wife in the domestic realm but can also provide emotional support to the wives. All forms of male perception and action are still the result of imitation of habits, customs, and social norms seen and learned in society.
Keywords: paternity leave, social construct, FGD, perception, Stuart Hall
Influencing Factors of Cross-Border e-Commerce Consumer Behavior-Taking in Malaysia
Authors: Vasudevan Hemaloshinee , Yu Keng
Published: November 2024

Cross-border e-commerce consumption drives growth, with consumer psychology and behavior varying based on culture, environment, and e-commerce platform systems. Malaysia's diverse and multilingual population necessitates a keen understanding of consumer psychology and behavior for merchants aiming to penetrate the market. This paper explores consumer behavior in Malaysia's cross-border e-commerce, analyzing factors such as perceived value, purchase intention, and behavior theories. Consumers' psychological characteristics significantly influence their decision-making behavior when shopping on cross-border e-commerce, influenced by the shopping experience and online shopping issues. The research provides a contribution reference for nations or businesses to develop a cross-border e-commerce strategy. The study investigates Malaysian e-commerce consumers through a questionnaire survey, utilizing a non-probability technique with convenience sampling, resulting in 508 valid responses. The study is based on herd consumption psychology and consists of three dimensions: informational influence, normative influence, and value expression influence. The study found a significant correlation between crowd consumption psychology's informational influence and consumers' perceived usefulness and purchase intention with a p-value of 0.001, 0.000, and 0.125, while normative and value expression influences were insignificant. The study provides empirical and conceptual evidence to support the government's initiative on navigating international regulations in cross-border e-commerce, a complex yet crucial task. Customs administrations must collaborate with all stakeholders to develop a comprehensive approach for managing e-commerce transactions, focusing on trade facilitation and enforcement. It recommends reviewing the accurate measurement of cross-border e-commerce, which is crucial for making informed policy and business decisions.
Irisin Attenuates Hepatic Stellate Cell Activation and Liver Fibrosis in Bile Duct Ligation Mice Model and Improves Mitochondrial Dysfunction
Authors: Lai Thuy Linh , Park So Young , Nguyen Giang , Pham Phuc Thi Minh , Kang Seon Mee , Hong Jeana , Lee Jae-Ho , Im Seung-Soon , Choi Dae-Hee , Cho Eun-Hee
Published: November 2024

Background: Liver fibrosis is a common outcome of chronic liver disease and is primarily driven by hepatic stellate cell (HSC) activation. Irisin, a myokine released during physical exercise, is beneficial for metabolic disorders and mitochondrial dysfunction. This study aimed to explore the effects of irisin on liver fibrosis in HSCs, a bile duct ligation (BDL) mouse model, and the associated mitochondrial dysfunction.Methods: In vitro experiments utilized LX-2 cells, a human HSC line, stimulated with transforming growth factor-β1 (TGF-β1), a major regulator of HSC fibrosis, with or without irisin. Mitochondrial function was assessed using mitochondrial fission markers, transmission electron microscopy, mitochondrial membrane potential, and adenosine triphosphate (ATP) production. In vivo, liver fibrosis was induced in mice via BDL, followed by daily intraperitoneal injections of irisin (100 μg/kg/day) for 10 days.Results: In vitro, irisin mitigated HSC activation and reduced reactive oxygen species associated with the TGF-β1/Smad signaling pathway. Irisin restored TGF-β1-induced increases in fission markers (Fis1, p-DRP1) and reversed the decreased expression of TFAM and SIRT3. Additionally, irisin restored mitochondrial membrane potential and ATP production lowered by TGF-β1 treatment. In vivo, irisin ameliorated the elevated liver-to-body weight ratio induced by BDL and alleviated liver fibrosis, as evidenced by Masson’s trichrome staining. Irisin also improved mitochondrial dysfunction induced by BDL surgery.Conclusion: Irisin effectively attenuated HSC activation, ameliorated liver fibrosis in BDL mice, and improved associated mitochondrial dysfunction. These findings highlight the therapeutic potential of irisin for the treatment of liver fibrosis.
Investigation of the approximate solution of one class of curvilinear integral equations by the projection method
Authors: Khalilov Elnur H. , Aliev Araz R. , Musayev Ali M.
Published: November 2024

UDC 517.9
We prove the existence theorem for the normal derivative of the double-layer potential and establish the formula for its evaluation. A new method for the construction of quadrature formulas for the normal derivatives of simple- and double-layer potentials is developed, and the error estimates are obtained for the constructed quadrature formulas. By using these quadrature formulas, the integral equation of the exterior Dirichlet boundary-value problem for the Helmholtz equation in two-dimensional space is replaced by a system of algebraic equations, and the existence and uniqueness of the solution to this system is proved.  The convergence of the solution of the system of algebraic equations to the exact solution of the integral equation at the control points is proved and the convergence rate of the method is determined.
Про застосування методу усереднення до однієї задачі оптимального керування з нефіксованим часом
Authors: Ogul B.
Published: November 2024

УДК 517.9
Розглянуто задачу оптимального керування системою диференціальних рівнянь зі швидкоколивними коефіцієнтами та коерцитивним цільовим функціоналом. Кінцевий момент часу не фіксований і визначається як перший момент потрапляння фазової точки на задану замкнену обмежену підмножину фазового простору. Доведено розв'язність цієї задачі та обґрунтовано збіжність оптимальних розв'язків вихідної задачі до оптимального процесу задачі з усередненими параметрами.
The Role of Magnetic Skeleton in Solar Flare Filaments Activity
Authors: Guo Juan , Wang Huaning , Wang Jingxiu , Zhu Xiaoshuai , Huang Jing , Chen Shanqiang , Luo Bingxian , Liu Siqing , Deng Yuanyong , Lin Jiaben
Published: November 2024

We report an M9.3 flare and filaments activities from NOAA Active Region 11261 that are strongly modulated by the 3D magnetic skeleton. Magnetic field extrapolation from the vector magnetic field suggests complex magnetic connectivity and the existence of a high coronal null point southeast of the active region. A small filament over the inversed V-shaped polarity inversion line erupted and resulted in the M9.3 flare associated with a weak ejection in the EUV hot channel and the formation of a relatively large filament. Both the weak ejection and the eruption of the large filament were toward the southeast. Comparative analyses have disclosed the following new facts. First, the trajectory of looptop hard X-ray emission provides solid evidence that the magnetic reconnection site propagated up toward the coronal null point as the flare and filaments erupted. Second, the EVU observations show coronal mass ejection-like eruption features in the ejection region of the magnetic skeleton. Third, the closed fan confined the west end of the large filament and the corresponding flare ribbons. We demonstrate a spatiotemporal relationship between the magnetic skeleton and the flare filament activity. We conclude that the magnetic skeleton can modulate and determine almost all the characteristics of the studied activity in the corresponding scale.
Testing the Accuracy of Spectral Energy Distribution Modeling Techniques Using the NIHAO-SKIRT-Catalog
Authors: Faucher Nicholas , Blanton Michael R.
Published: November 2024

We use simulated galaxy observations from the NIHAO-SKIRT-Catalog to test the accuracy of spectral energy distribution (SED) modeling techniques. SED modeling is an essential tool for inferring star formation histories from nearby galaxy observations but is fraught with difficulty due to our incomplete understanding of stellar populations, chemical enrichment processes, and the nonlinear, geometry-dependent effects of dust. The NIHAO-SKIRT-Catalog uses hydrodynamic simulations and radiative transfer to produce SEDs from the ultraviolet (UV) through the infrared (IR), accounting for dust. We use the commonly used Prospector software to perform inference on these SEDs and compare the inferred stellar masses and star formation rates (SFRs) to the known values in the simulation. We match the stellar population models to isolate the effects of differences in the star formation history, the chemical evolution history, and the dust. For the high-mass NIHAO galaxies (>109.5
M
⊙), we find that model mismatches lead to inferred SFRs that are on average underestimated by a factor of 2 when fit to UV through IR photometry, and a factor of 3 when fit to UV through optical photometry. These biases lead to significant inaccuracies in the resulting specific SFR–mass relations, with UV through optical fits showing particularly strong deviations from the true relation of the simulated galaxies. In the context of massive existing and upcoming photometric surveys, these results highlight that star formation history inference from photometry may remain imprecise and inaccurate and that there is a pressing need for more realistic testing of existing techniques.
Studying the Effect of Radiation Pressure on Evolution of a Population III Stellar Cluster
Authors: Kundu Sukalpa , Dutta Jayanta
Published: November 2024

Recent numerical simulations have shown that the unstable disk within the central regime of the primordial gas cloud fragments to form multiple protostars on several scales. Their evolution depends on the mass accretion phenomenon, interaction with the surrounding medium and radiative feedback respectively. In this work, we use a fast semianalytical framework in order to model multiple protostars within a rotating cloud, where the mass accretion is estimated via a Bondi–Hoyle flow and the feedback process is approximated through radiation pressure. We observe that while some of the evolving protostars possibly grow massive (≈1–75 M
⊙) via accretion and mergers, a fraction of them (≈20%) are likely to be ejected from the parent cloud with a mass corresponding to M
* ≲ 0.8 M
⊙. These low-mass protostars may be considered as the potential candidates to enter the zero-age-main-sequence phase and possibly survive until the present epoch.
Common Envelopes, Gamma Rays, and Sudden Spectral Changes of Novae
Authors: Williams Robert , Ryan Russell , Rudy Richard
Published: November 2024

A common envelope (CE) is proposed as the origin of the early post-outburst spectra of many novae. A simple model is proposed to explain the properties of the CE based on the emission line strengths and an assumed density distribution. Rapid changes in the spectrum during post-outburst decline are suggested as possible evidence for a CE. Time-resolved spectra from the ARAS group show sudden spectral shifts that are correlated with detected γ-ray emission, suggestive of its possible origin on the white dwarf that produces a change in condition within the CE. Episodic mass loss, formation of transient heavy element absorption systems, and dissipation of the CE may possibly be triggered by γ-ray emission.
Joint Observations of Late Universe Probes: Cosmological Parameter Constraints from Gravitational Wave and Type Ia Supernova Data
Authors: Zheng Jie , Liu Xiao-Hui , Qi Jing-Zhao
Published: November 2024

The growing tensions between the early Universe and the late Universe increasingly highlight the importance of developing precise probes for late cosmology. As significant late-Universe probes, Type Ia supernovae (SNe Ia) and gravitational waves (GWs) can provide measurements of relative and absolute distances, respectively. Their complementary nature is likely to break the degeneracies among cosmological parameters, thereby yielding more precise constraints. In this study, we use 43 gravitational-wave sources from the Third LIGO–Virgo–KAGRA Gravitational-Wave Transient Catalog (GWTC-3) and 1590 light curves from Pantheon+ compilation to constrain the dark energy models, as an attempt to achieve precise late-Universe cosmological constraints. For the dark siren GW event, we estimate the corresponding redshift using the binary black hole redshift distribution model. The combination of GW and SNe Ia data could provide the precision on the Hubble constant H
0 and the present matter density Ω
m
of approximately 16% and 8% for the ΛCDM model. If we consider the equation of state of dark energy w, the combination sample constrains the precision of w to approximately 24%. Although the combination of GWs and SNe Ia observations effectively breaks degeneracies among various cosmological parameters, yielding more stringent constraints, the precision of these constraints still does not meet the stringent standards required by precision cosmology. However, it is reasonable to anticipate that, in the near future, the joint observations of GWs and SNe Ia will become a powerful tool, particularly in the late Universe, for the precise measurement of cosmological parameters.
Impact of Systematic Modeling Uncertainties on Kilonova Property Estimation
Authors: Brethauer D. , Kasen D. , Margutti R. , Chornock R.
Published: November 2024

The precise atomic structure and therefore the wavelength-dependent opacities of lanthanides are highly uncertain. This uncertainty introduces systematic errors in modeling transients like kilonovae and estimating key properties such as mass, characteristic velocity, and heavy metal content. Here, we quantify how atomic data from across the literature as well as choices of thermalization efficiency of r-process radioactive decay heating impact the light curve and spectra of kilonovae. Specifically, we analyze the spectra of a grid of models produced by the radiative transfer code Sedona that span the expected range of kilonova properties to identify regions with the highest systematic uncertainty. Our findings indicate that differences in atomic data have a substantial impact on estimates of lanthanide mass fraction, spanning approximately 1 order of magnitude for lanthanide-rich ejecta, and demonstrate the difficulty in precisely measuring the lanthanide fraction in lanthanide-poor ejecta. Mass estimates vary typically by 25%–40% for differing atomic data. Similarly, the choice of thermalization efficiency can affect mass estimates by 20%–50%. Observational properties such as color and decay rate are highly model dependent. Velocity estimation, when fitting solely based on the light curve, can have a typical error of ∼100%. Atomic data of light r-process elements can strongly affect blue emission. Even for well-observed events like GW170817, the total lanthanide production estimated using different atomic data sets can vary by a factor of ∼6.
Efficient Stochastic Template Bank Using Inner Product Inequalities
Authors: Kacanja Keisi , Nitz Alexander H. , Wu Shichao , Cusinato Marco , Dhurkunde Rahul , Harry Ian , Dal Canton Tito , Pannarale Francesco
Published: November 2024

Gravitational wave searches are crucial for studying compact sources such as neutron stars and black holes. Many sensitive modeled searches use matched filtering to compare gravitational strain data to a set of waveform models known as template banks. We introduce a new stochastic placement method for constructing template banks, offering efficiency and flexibility to handle arbitrary parameter spaces, including orbital eccentricity, tidal deformability, and other extrinsic parameters. This method can be computationally limited by the ability to compare proposal templates with the accepted templates in the bank. To alleviate this computational load, we introduce the use of inner product inequalities to reduce the number of required comparisons. We also introduce a novel application of Gaussian Kernel Density Estimation to enhance waveform coverage in sparser regions. Our approach has been employed to search for eccentric binary neutron stars, low-mass neutron stars, primordial black holes, and supermassive black hole binaries. We demonstrate that our method produces self-consistent banks that recover the required minimum fraction of signals. For common parameter spaces, our method shows comparable computational performance and similar template bank sizes to geometric placement methods and stochastic methods, while easily extending to higher-dimensional problems. The time to run a search exceeds the time to generate the bank by a factor of

O
(

10

5

)

for dedicated template banks, such as geometric, mass-only stochastic, and aligned spin cases,

O
(

10

4

)

for eccentric and

O
(

10

3

)

for the tidal deformable bank. With the advent of efficient template bank generation, the primary area for improvement is developing more efficient search methodologies.
Radiative Pressure on Fractal Dust Grains in Oxygen-rich AGB Stars
Authors: Ferguson Frank T. , Nuth Joseph A. , Paquette John A.
Published: November 2024

There is still considerable debate on the exact composition of grains formed in the outflows of O-rich, asymptotic giant branch stars. Estimates of the expected condensation distances based on radiative transfer calculations show that iron-free silicates can condense close to the star but typically lack the opacity to drive an outflow unless they are large enough that radiation pressure due to scattering on the grains becomes significant. Iron-containing silicates have a much higher absorption opacity, but due to this stronger absorption, their expected condensation location is well beyond the expected dust formation zone. Recent measurements of the efficiency of SiO condensational growth have shown that this rate is low. The result of this low growth efficiency is that nucleation may persist for longer, giving a larger number of smaller primary particles, leading to an increased likelihood of particle aggregation in these outflows. In this work, we examine how the radiation pressure changes with the possible aggregation of these primary particles into fractal aggregates. Opacity calculations are made using optical properties of both forsterite and astronomical silicate for aggregates containing up to 256 primary particles and for fractal dimensions of 1.8 and 2.8. For primary particles of radius less than ∼0.1 μm, aggregation leads to an enhancement of the radiation pressure over an equivalent cloud of isolated primary particles.
Memory in the Burst Occurrence of Repeating Fast Radio Bursts
Authors: Wang Ping , Song Li-Ming , Xiong Shao-Lin , Zhao Xiao-Yun , Wang Jin , Zhao Shu-Min , Xiao Shuo , Cai Ce , Xie Sheng-Lun , Xue Wang-Chen , Wang Chen-Wei , Wang Yue , Zhang Wen-Long
Published: November 2024

Understanding the nature of repeating fast radio bursts (FRBs) is crucial for probing their underlying physics. In this work, we analyze the waiting time statistics between bursts of three repeating FRBs from four data sets. We find a universally pronounced dependency of the waiting times on the previous time interval (denoted as λ
0). We observe a temporal clustering, where short waiting times tend to be followed by short ones and long by long, comparative to their mean value. This memory dependency is manifested in the conditional mean waiting time as well as in the conditional mean residual time to the next burst, both of which increase in direct proportion to λ
0. Consequently, the likelihood of experiencing a subsequent FRB burst within a given time window after the preceding burst is generally influenced by the burst history. We reveal, for the first time, that these memory effects are present in the scale-invariant preconditioned waiting time distribution. We show that the memory effect provides a unified description of waiting times that may account for both the repeating FRBs and the apparently nonrepeating FRBs (i.e., those only observed one time). These results shed new light on the mechanism of FRBs.
Measurements of Sunspot Group Tilt Angles Based on SOHO/MDI and SDO/HMI Magnetograms
Authors: Zeng Shu-Guang , Zhao Ao-Yu , Yi Shuang , Zheng Sheng , Zeng Xiang-Yun , Deng Lin-Hua , Huang Yao
Published: November 2024

The tilt angle of sunspot groups plays a crucial role in solar dynamo models for the generation of the poloidal field, yet the statistical properties of the tilt angle are not fully comprehended. This study employs magnetograms from the Solar and Heliospheric Observatory/Michelson Doppler Imager and Solar Dynamics Observatory/Helioseismic and Magnetic Imager to measure the tilt angles of 11,373 sunspot groups over the period from 2008 to 2023. This comprehensive analysis examines the relationship between the tilt angle and latitude of the sunspot groups, as well as the correlation between the tilt angle and solar cycle strength. The methodology involves calculating tilt angles within the ±45° central meridian distance, comparing mean-based and median-based measurements, and applying specific angular separation criteria. The findings reveal that during solar cycle 24, the tilt angles increase by approximately 4° for every 10° increase in latitude, in line with Joy’s law. A significant anticorrelation is observed between the latitude-normalized tilt angle (γ/∣L∣) and solar cycle strength. The research also uncovers a substantial hemispheric asymmetry in tilt angle parameters, with the southern hemisphere (m
Joy: 0.23 ± 0.092 ∼ 0.24 ± 0.074, γ = 8.°14 ± 0.°43 ∼ 9.°04 ± 0.°486) consistently showing larger tilt angles than the northern hemisphere (m
Joy: 0.47 ± 0.096 ∼ 0.51 ± 0.062, γ = 6.°14 ± 0.°304 ∼ 6.°64 ± 0.°334).
Convective Magnetic Flux Emergence Simulations from the Deep Solar Interior to the Photosphere: Comprehensive Study of Flux Tube Twist
Authors: Toriumi Shin , Hotta Hideyuki , Kusano Kanya
Published: November 2024

The emergence of magnetic flux from the deep convection zone plays an important role in solar magnetism, such as the generation of active regions and triggering of various eruptive phenomena, including jets, flares, and coronal mass ejections. To investigate the effects of magnetic twist on flux emergence, we performed numerical simulations of flux tube emergence using the radiative magnetohydrodynamic code R2D2 and conducted a systematic survey on the initial twist. Specifically, we varied the twist of the initial tube both positively and negatively from zero to twice the critical value for kink instability. As a result, regardless of the initial twist, the flux tube was lifted by the convective upflow and reached the photosphere to create sunspots. However, when the twist was too weak, the photospheric flux was quickly diffused and not retained long as coherent sunspots. The degree of magnetic twist measured in the photosphere conserved the original twist relatively well and was comparable to actual solar observations. Even in the untwisted case, a finite amount of magnetic helicity was injected into the upper atmosphere because the background turbulence added helicity. However, when the initial twist exceeded the critical value for kink instability, the magnetic helicity normalized by the total magnetic flux was found to be unreasonably larger than the observations, indicating that the kink instability of the emerging flux tube may not be a likely scenario for the formation of flare-productive active regions.
A Data-driven Magnetohydrodynamic Simulation of the 2011 February 15 Coronal Mass Ejection from Active Region NOAA 11158
Authors: Fan Yuhong , Kazachenko Maria D. , Afanasyev Andrey N. , Fisher George H.
Published: November 2024

We present a boundary data-driven magnetohydrodynamic (MHD) simulation of the 2011 February 15 coronal mass ejection (CME) event of Active Region NOAA 11158. The simulation is driven at the lower boundary with an electric field derived from the normal magnetic field and the vertical electric current measured from the Solar Dynamics Observatory (SDO) Helioseismic Magnetic Imager vector magnetograms. The simulation shows the buildup of a pre-eruption coronal magnetic field that is close to the nonlinear force-free field extrapolation, and it subsequently develops multiple eruptions. The sheared/twisted field lines of the pre-eruption magnetic field show qualitative agreement with the brightening loops in the SDO Atmospheric Imaging Assembly (AIA) hot passband images. We find that the eruption is initiated by the tether-cutting reconnection in a highly sheared field above the central polarity inversion line and a magnetic flux rope with dipped field lines forms during the eruption. The modeled erupting magnetic field evolves to develop a complex structure containing two distinct flux ropes and produces an outgoing double-shell feature consistent with the Solar Terrestrial Relations Observatory B/Extreme UltraViolet Imager observation of the CME. The foot points of the erupting field lines are found to correspond well with the dimming regions seen in the SDO/AIA observation of the event. These agreements suggest that the derived electric field is a promising way to drive MHD simulations to establish the realistic pre-eruption coronal field based on the observed vertical electric current and model its subsequent dynamic eruption.
Formation of Jupiter-mass Binary Objects through Photoerosion of Fragmenting Cores
Authors: Diamond Jessica L. , Parker Richard J.
Published: November 2024

The recent discovery of tens of Jupiter-mass binary objects (JuMBOs) in the Orion Nebula Cluster (ONC) with the James Webb Space Telescope has intensified the debate on the origin of free-floating planetary mass objects within star-forming regions. The JuMBOs have masses below the opacity limit for fragmentation but have very wide separations (from tens to hundreds of astronomical units), suggesting that they did not form in a similar manner to other substellar mass binaries. Here, we propose that the theory of photoerosion of prestellar cores by Lyman continuum radiation from massive stars could explain the JuMBOs in the ONC. We find that for a range of gas densities the final substellar mass is comfortably within the JuMBO mass range, and the separations of the JuMBOs are consistent with those of more massive (G- and A-type) binaries, which would have formed from the fragmentation of the cores had they not been photoeroded. The photoerosion mechanism is most effective within the H ii region(s) driven by the massive star(s). The majority of the observed JuMBOs lie outside of these regions in the ONC, but they may have formed within them and then subsequently migrated due to dynamical evolution.