bluuebunny/crossref_metadata_2025_split huggingface dataset:
Perubahan Struktur Demografis Indonesia: Tantangan & Rekomendasi
Authors: Sukmatika Anak Agung Yumas 
Published: January 2025

Indonesia menghadapi perubahan struktur demografis yang signifikan pada periode 2020-2040. Selama periode ini, diperkirakan jumlah penduduk usia produktif (15-64 tahun) akan mencapai 64% dari total populasi sekitar 300 juta jiwa. Apabila dikelola dengan baik, kondisi demografi ini dapat mendorong Indonesia dalam meraih dividen demografis yang berdampak besar terhadap pertumbuhan ekonomi dan kesejahteraan masyarakat. Dalam hal ini, dividen demografis mendorong peningkatan produktivitas ekonomi ketika jumlah penduduk yang bekerja meningkat atau lebih besar dibandingkan dengan jumlah penduduk yang ditanggung atau tidak bekerja. Negara dengan konsentrasi besar terhadap penduduk usia kerja memiliki keunggulan inheren dalam menghasilkan tingkat pendapatan per kapita yang tinggi. Dalam periode ini, dua entitas demografis dominan yang ada di Indonesia adalah kelas menengah dan generasi milenial. Memahami karakteristik kedua entitas tersebut dapat menjadi dasar bagi pemerintah untuk menentukan langkah-langkah yang tepat dalam memanfaatkan window of opportunity dalam meraih dividen demografis dan pertumbuhan ekonomi berkelanjutan di Indonesia.
Analisis Kegiatan Pengembangan Koleksi Open Library Telkom University
Authors: Tyas Zahra Wenning 
Published: January 2025

As an effort to meet the needs of users and realize its position as a center of science and information sources through the collection of library collections, Open Library Telkom University carries out a collection development process. Research about collection development at Open Library Telkom University is important, to explain the stages of collection development and analyze the suitability of collection development activities at Open Library Telkom University with the principles of collection development. The purpose of this research is to analyze and explain the stages of collection development at Open Library Telkom University. The methods used in this research are descriptive qualitative methods and data collection techniques carried out through observation, interviews, and literature studies. The findings of this research that collection development at Open Library Telkom University includes user needs analysis activities through a library collections needs analysis survey that is distributed to the study program, carrying out collection development activities in accordance with established policies, selecting library collections, procuring libraries tailored to the type of library and user needs, carrying out weeding of library collections, and evaluation of library development activities. Collection development activities at Open Library Telkom University have been carried out systematically and in accordance with the stages and principles of collection development.
Failure Resolution of Exhaust Manifold used in Commercial Vehicle Engines
Authors: Abdul Rahiem A  , K Krishnamoorthy , Sunilraj S  , Sarathaswin B  , Dr. Koorella Krishna  
Published: January 2025

A comprehensive metallurgical investigation was undertaken to elucidate the causes of exhaust manifold failures in both compressed natural gas and diesel engines. This investigation encompassed a thorough material analysis, encompassing chemical composition, microstructural characterization, identification of casting defects, and evaluation of mechanical properties. Additionally, fractography studies were conducted on the fractured surfaces to gain insights into crack initiation and propagation mechanisms. The findings of these analyses revealed that the observed wall thinning was potentially due to core shifting during the casting process, coupled with the presence of casting defects. These factors collectively contributed to the failure of the exhaust manifold.
Keywords: Exhaust manifold, Cast iron, Wall thinning, Core shifting, Casting.
Las úlceras por presión en la superación profesional del especialista en medicina general integral
Authors: Ramírez Lara Evelio José , Rodríguez Companioni Osmel 
Published: January 2025

Based on the insufficiencies in the performance of the specialist in Integral General Medicine (IGM), the objective of the research was defined: to assess the importance of integrating the prevention and treatment of pressure ulcers as content of the professional improvement process of the specialist in IGM in a new theoretical-methodological conception. The integration of the theoretical foundations showed limitations when assuming the contents of said process, from adequate didactic and methodological procedures. We conceived the methodology from the integration of quantitative and qualitative aspects with the participation of twenty specialists and six managers, with the use of different methods: survey, observation of medical practice, group interview, document analysis and socialization workshop with specialists. The foundation and the diagnosis made justified the need for a new point of view of the professional improvement process of the IGM specialist. We proposed a theoretical-methodological conception from a critical-reflexive, participatory and contextualized approach, as support for methodological procedures for its subsequent objectification. We confirmed the value and significance of the proposal.
La presencia del racismo en grupo étnico apaches nativo- americanos; silver city, Nuevo México, E.U.A.
Authors: Martínez Salomón Elvira 
Published: January 2025

The importance of the issue of racism present in the apache ethnic group is of great relevance due to the sense of urgency that the ways in which racism is represented must be made visible. The research offers relevance because it makes visible the current situation of the representations of racism, due to the importance of the apache culture it becomes relevant; since there is a shortage of studies directly related to the topic and the ethnic group, the justification of the research is the contribution of knowledge of the presence and forms of racism; It stands out that the most predominant is due to its color, without leaving aside education, ethnicity, language, culture, religion, sacred ceremonies, social classes and ranks, technological changes, among other forms of representation. The main objective is to determine the ways in which racism occurs among the original Apache settlers. The methodology applied is under the qualitative approach, with an ethnographic method, grounded theory is used; The study is conducted in Silver City, New Mexico, USA. with the support of Western New Mexico University, during an academic stay carried out by the author in May 2018. Finally, the results are presented that show the presence of racism in its different forms such as language, origin, sacred ceremonies, education and lack of inclusion in the study programs of the times that the ethnic group requires for its sacred ceremonies; The conclusions are presented, establishing lines of research for future studies.
Disgust memory enhancement extends to more accurate memory but not more false memories
Authors: Matson Lucy A. , Moeck Ella K. , Molyneux Tyla R. , Takarangi Melanie K. T. 
Published: January 2025

Abstract
People show enhanced memory recall for disgust over fear, despite both being highly negative and arousing emotions. But does disgust’s ‘stickiness’ in memory result in more false memories for disgust versus fear? Existing research finds low false-memory rates for disgust and fear, perhaps from using image lures depicting content unrelated to target images. Therefore, we presented 111 participants with disgust, fear, (and neutral) images during an attention-monitoring task. After 24–48 hours, participants completed a recognition test, where they viewed ‘old’ (previously seen) and ‘new’ images (both related and unrelated lures) and indicated whether each image was ‘old’ or ‘new’. Relative to fear, participants experienced fewer false memories of disgust for unrelated lures, but similar false memories for related lures. Furthermore, participants’ attention was captured more by disgust than fear images, and correct recognition and memory sensitivity were enhanced for disgust relative to fear. Our findings suggest disgust memory enhancement extends to accurate memory, which has clinical implications.
Academic Stress and Students' Mental Health
Authors: Akter Rozina , Barua Dhiman 
Published: January 2025

The mental health of students is an issue of concern worldwide. At the tertiary level, students face several stresses, including academic stress. Frequent changes in curriculum and examination systems put pressure on students’ mental health. In this study, we aim to explore the relationship between mental health and academic stress. The study is conducted on the students of six private universities located in Dhaka and Chattogram. An adopted questionnaire is used to measure the academic stress and mental health of the students. A Google form questionnaire designed in a five-point Likert scale is sent to the students by using convenient sampling techniques. SPSS version 23 is used for statistical analysis. A total of 297 responses are considered for statistical analysis. Multiple Regression Models are used to analyze the data. The study finds a positive significant correlation between four dimensions of academic stress and the mental health of the respondents. The finding provides educational institutions with an insight into creating mechanisms through which actual and potential mental health issues among students can be addressed. The study includes a small sample size and is conducted only on business students of private universities. Further research may be conducted on the students of other disciplines of both public and private universities and a larger sample.
Hydroxyl Lines and Moonlight: A High Spectral Resolution Investigation of Near-infrared Skylines from Maunakea to Guide Near-infrared Spectroscopic Surveys
Authors: Dauphin Frederick , Petric Andreea , Artigau Étienne , Stephens Andrew W. , Cook Neil James , Businger Steven , Flagey Nicolas , Marshall Jennifer , Ntampaka Michelle , Ravindranath Swara , Rousseau-Nepton Laurie 
Published: January 2025

Abstract
Subtracting the changing sky contribution from the near-infrared (NIR) spectra of faint astronomical objects is challenging and crucial to a wide range of science cases such as estimating the velocity dispersions of dwarf galaxies, studying the gas dynamics in faint galaxies, measuring accurate redshifts, and any spectroscopic study of faint targets. Since the sky background varies with time and location, NIR spectral observations, especially those employing fiber spectrometers and targeting extended sources, require frequent sky-only observations for calibration. However, sky subtraction can be optimized with sufficient a priori knowledge of the sky's variability. In this work, we explore how to optimize sky subtraction by analyzing 1075 high-resolution NIR spectra from the Canada–France–Hawaii Telescope's SPIRou on Maunakea, and we estimate the variability of 481 hydroxyl (OH) lines. These spectra were collected during two sets of three nights dedicated to obtaining sky observations every 5.5 minutes. During the first set, we observed how the Moon affects the NIR, which has not been accurately measured at these wavelengths. We suggest accounting for the Moon contribution at separation distances less than 10° when (1) reconstructing the sky using principal component analysis, (2) observing targets at YJHK magnitudes fainter than ∼15, and (3) attempting a sky subtraction better than 1%. We also identified 126 spectral doublets, or OH lines that split into at least two components, at SPIRou's resolution. In addition, we used Lomb–Scargle periodograms and Gaussian process regression to estimate that most OH lines vary on similar timescales, which provides a valuable input for IR spectroscopic survey strategies. The data (https://zenodo.org/records/13363061) and code (https://github.com/FDauphin/spirou-sky-subtraction) developed for this study are publicly available.
Dissecting the Interstellar Media of a Wolf–Rayet Galaxy at z = 2.76
Authors: Morishita Takahiro , Stiavelli Massimo , Schuldt Stefan , Grillo Claudio 
Published: January 2025

Abstract
We report JWST/NIRSpec observations of a star-forming galaxy at z = 2.76, MACS J1149-WR1. We securely detect two temperature-sensitive auroral lines, [S iii] 6312 (7.4σ) and [O ii] 7320+7331 doublets (10σ), and tentatively [n ii] 5755 (2.3σ) for the first time in an individual galaxy at z > 1. We perform a detailed analysis of its interstellar media (ISM), and derive electron temperatures, various heavy element abundances (O/H, N/O, S/O, and Ar/O) in the hot ionized region, and the neutral fraction in the warm ionized region. MACS J1149-WR1 shows a broad feature at the wavelength of He ii 4686, which consists of a broad (∼1000 km s−1), blueshifted (∼−110 km s−1) line component. Taken together with its mildly elevated N/O abundance, we conclude that MACS J1149-WR1 is experiencing a young starburst (≲10 Myr), likely hosting a large number of Wolf–Rayet (W-R) stars. None of its spectral features support the presence of active galactic nuclei, including (i) the absence of broad components and velocity shifts in hydrogen recombination lines, (ii) low [Fe ii]1.257 μm/Paβ ratio, and (iii) the absence of high-ionization lines. Our analysis using He i lines reveals a higher electron temperature and a higher attenuation value, indicating that He i may probe a smaller spatial scale than H i, presumably the region dominated by the aforementioned W-R stars. The star formation rates derived from various He i lines broadly agree with those from hydrogen recombination lines. We thus advocate that He i can be an excellent, independent probe of multiphase ISM in the era of JWST.
Dependence of Metal Enrichment of Nuclear Star Clusters on Galaxy Stellar Mass
Authors: Lyu Wenhe , Zhang Hong-Xin , Paudel Sanjaya , Li Tie , Tang Yimeng , Chen Guangwen , Kong Xu , Peng Eric W. 
Published: January 2025

Abstract
Nuclear star clusters (NSCs) are commonly found in the centers of galaxies, but their dominant formation mechanisms remain elusive. We perform a consistent analysis of stellar populations of 97 nearby NSCs, based on spectroscopic data from the Very Large Telescope. The sample covers a galaxy stellar mass range of 107–1011
M
⊙ and is more than 3 times larger than any previous study. We identify three galaxy stellar mass regimes with distinct NSC properties. In the low-mass regime of

log

M

host

≲ 8.5 (M
host is in units of M
⊙), nearly all NSCs have metallicities lower than their circum-NSC host but similar to those of typical red globular clusters (GCs), supporting the GC inspiral–merger scenario of NSC formation. In the high-mass regime of

log

M

host

≳ 9.5, nearly all NSCs have higher metallicities than their circum-NSC host and red GCs, suggesting significant contributions from in situ star formation. In the intermediate-mass regime, a comparable fraction of NSCs have higher or lower metallicities than their circum-NSC host and red GCs, with no clear dependence on NSC mass, suggesting intermittent in situ star formation. The majority of NSCs with higher metallicities than their host exhibit a negative age–metallicity correlation, providing clear evidence of long-term chemical enrichment. The average metallicity difference between NSC and host peaks broadly around

log

M

host

∼
9.8

and declines toward both higher and lower galaxy masses. We find that the efficiency of dynamical-friction-driven inspiral of GCs observed in present-day galaxies can explain the NSC mass at

log

M

host

≲
9.5

but falls short of observed ones at higher galaxy mass, reinforcing our conclusions based on stellar population analysis.
On Disk Formation around Isolated Black Holes via Stream Accretion
Authors: Tripathi Priyesh Kumar , Chattopadhyay Indranil , Joshi Raj Kishor 
Published: January 2025

Abstract
We investigate accretion onto an isolated black hole from uniform winds. If the winds are directed toward the black hole, then the accretion process can be well described by the classical Bondi–Hoyle–Lyttleton or BHL accretion. If the wind is not directed toward the black hole and flows past it, then a smaller fraction of the flow can be attracted by the black hole, and this type of accretion cannot be described by the classical BHL, and we coin the second kind as the lateral BHL. We show that the classical BHL cannot form an accretion disk, while lateral BHL can form transient accretion disks. To describe the thermodynamics of the flow, we have used a variable adiabatic index equation of state which depends on the temperature of the flow as well as the composition of the gas. We show that the electron-proton gas forms an accretion disk, which disappears and forms a shock cone, only to form the disk again at a later time, while for flows with fewer protons, the accretion disk, once lost, does not reappear again. Only when the flow is pair-dominated does it form a persistent accretion disk. We also show that a shock cone is less luminous than the accretion disk.
Exploring the Circumstellar Environment of Tycho’s Supernova Remnant. II. Impact on the Broadband Nonthermal Emission
Authors: Kobashi Ryosuke , Lee Shiu-Hang , Tanaka Takaaki , Maeda Keiichi 
Published: January 2025

Abstract
While the environment around Tycho's supernova remnant has long been believed to be close to homogeneous, the latest analysis of Chandra data has identified a substantial deceleration of the forward shock, which poses a major challenge to this picture. R. Kobashi et al. showed that the existence of dense molecular cloud (MC) surrounding a rarefied wind-like circumstellar matter (CSM) can explain this observational finding in terms of the shock-expansion dynamics, supporting the so-called single-degenerate scenario for the progenitor system. We here extend this work to study the nonthermal emission processes and investigate whether such an environment is consistent with the observed multiwavelength spectrum. While the simulated broadband spectrum based on the wind–MC environment is largely consistent with observations, we find that such an environment predicts a harder gamma-ray spectrum than observed due to the relatively low CSM density in the cavity interior of the MC. This difference can be at least partially attributed to the present 1D setup of the model, which does not account for the clumpy and multidimensional structure of the CSM. Our model provides predictions for the long-term evolution of the broadband spectrum, which can be used to further probe Tycho's surrounding environment in the future, a key to resolving the long-standing issue of Type Ia supernova progenitor channels.
Broad-line Region Characterization in Dozens of Active Galactic Nuclei Using Small-aperture Telescopes
Authors: Sobrino Figaredo Catalina , Chelouche Doron , Haas Martin , Ramolla Michael , Kaspi Shai , Panda Swayamtrupta , Ochmann Martin W. , Zucker Shay , Chini Rolf , Probst Malte A. , Kollatschny Wolfram , Murphy Miguel 
Published: January 2025

Abstract
We present the results of a nearly decade-long photometric reverberation mapping (PRM) survey of the Hα emission line in nearby (0.01 ≲ z ≲ 0.05) Seyfert galaxies using small (15–40 cm) telescopes. Broadband filters were used to trace the continuum emission, while narrowband filters tracked the Hα-line signal. We introduce a new PRM formalism to determine the time delay between continuum and line emission using combinations of auto- and cross-correlation functions. We obtain robust delays for 33/80 objects, allowing us to estimate the broad-line region (BLR) size. Additionally, we measure multiepoch delays for six objects whose scatter per source is smaller than the scatter in the BLR size–luminosity relation. Our study enhances the existing Hα size–luminosity relation by adding high-quality results for 31 objects, whose nuclear luminosities were estimated using the flux-variation gradient method, resulting in a scatter of 0.26 dex within our sample. The scatter reduces to 0.17 dex when the six lowest-luminosity sources are discarded, which is comparable to that found for the Hβ line. Single-epoch spectra enable us to estimate black hole masses using the Hα line and derive mass accretion rates from the iron-blend feature adjacent to Hβ. A similar trend, as previously reported for the Hβ line, is implied whereby highly accreting objects tend to lie below the size–luminosity relation of the general population. Our work demonstrates the effectiveness of small telescopes in conducting high-fidelity PRM campaigns of prominent emission lines in bright active galactic nuclei.
A Short-lived Rejuvenation during the Decades-long Changing-look Transition in the Nucleus of Mrk 1018
Authors: Lu Kai-Xing , Li Yan-Rong , Wu Qingwen , Ho Luis C. , Zhang Zhi-Xiang , Feng Hai-Cheng , Li Sha-Sha , Chen Yong-Jie , Sun Mouyuan , Shu Xinwen , Guo Wei-Jian , Cheng Cheng , Wang Jian-Guo , Kim Dongchan , Wang Jian-Min , Bai Jin-Ming 
Published: January 2025

Abstract
Changing-look active galactic nuclei (CL-AGNs), characterized by the emergence or disappearance of broad lines accompanied by extreme continuum flux variability, have drawn much attention for their potential to reveal physical processes underlying AGN evolution. We perform seven-season spectroscopic monitoring on Mrk1018, one of the earliest identified CL-AGN. Around 2020, we detect a full-cycle changing-look transition of Mrk 1018 within one year, associated with a nucleus outburst, which likely arose from the disk instability in the transition region between the outer standard rotation-dominated disk and inner advection-dominated accretion flow. Over the past 45 years, the accretion rate of Mrk 1018 changed 1000 times and the maximum Eddington ratio reached 0.02. By investigating the relation between the broad-line properties and the Eddington ratio (L
bol/L
Edd), we find strong evidence that the full-cycle-type transition is regulated by accretion. There exists a turnover point in the Balmer decrement, which is observed for the first time. The broad Balmer lines change from a single peak in Types 1.0–1.2 to double peaks in Types 1.5–1.8, and the double-peak separation decreases with increasing accretion rate. We also find that the FWHM of the broad Balmer lines obeys FWHM

∝

(

L

bol

/

L

Edd

)

−
0.27

, as expected for a virialized broad-line region (BLR). The velocity dispersion σ
line follows a similar trend in Types 1.5–1.8 but displays a sharp increase in Types 1.0–1.2, resulting in a dramatic drop in FWHM/σ
line. These findings suggest that a virialized BLR together with accretion-dependent turbulent motions might be responsible for the diversity of BLR phenomena across the AGN population.