bluuebunny/crossref_metadata_2025 huggingface dataset:
Causales del Deficit de Construccion de Vivienda de Interes Social en el Municipio de Buenaventura – Colombia
Authors: Herrera Aguilar Edgar Julián
Published: January 2025

La Vivienda de Interés Social en Colombia, se entiende como “aquellas que se desarrollen para garantizar el derecho a la vivienda de los hogares de menores ingresos”, asegurando elementos de habitabilidad, estándares de calidad en diseño urbanístico, arquitectónico y de construcción. En este marco, el gobierno de Juan Manuel Santos, lanza en 2015 el programa para acceso a vivienda social, “Mi Casa Ya” él, tiene por objeto que personas que ganen entre 2 y 4 Salarios Mínimos Legales Mensuales Vigentes, accedan por una única vez, al subsidio de vivienda que le permita realizar el cierre financiero correspondiente al pago de la cuota inicial del inmueble, tasado en el 30% de su valor total. Buenaventura, se posa en el departamento del Valle del Cauca, la ciudad, posee el único puerto multimodal del país sobre el océano pacífico y mueve aproximadamente el 38% de la carga que exporta Colombia, Cali, es la capital del departamento, y alrededor de ella se posan cinco municipios que hacen parte de su zona conturbada, los cuales entre los años 2015 a 2024, que es el marco de tiempo establecido para esta investigación, obtuvieron 42.426 subsidios de vivienda del programa Mi Casa Ya, mientras que Buenaventura obtuvo 329 subsidios en el mismo período, ello, corresponde al 0.73% del total de subsidios focalizados. Las políticas municipales de Buenaventura para la construcción de vivienda nueva, no se han adaptado a las condiciones normativas y/o económicas establecidas por la nación y exigidas por el modelo económico que nos rige.
Numerical Unveiling the Dynamics of Glycerin-Water Mixing: Insights into Compatibility and Behavior
Authors: Abbas Fadhil Khalaf  , Farhan Lafta Rashid  , Hayder I. Mohammed  , Ali Basem  , Hussein Rasool Abid  , Mudhar A. Al-Obaidi
Published: January 2025

Investigating glycerin-water mixing dynamics in a vertical container with variable velocities is crucial for optimising industrial processes and understanding fluid behavior in diverse applications. Despite having several studies in the open literature that discussed the electrical and physical properties of glycerol/water mixtures, this study specifically investigates the dynamic interactions of glycerin-water mixing in a vertical container with variable water and glycerin intake velocities using ANSYS fluent v.16.1, to evaluate the associated spatial distribution inside the container. When glycerin and water are mixed, the combination form is a homogenous solution. The optimal glycerin-to-water ratio is conditional on the application at hand. At a mixing speed of 0.1 m/s, glycerin and water exhibit a phenomenon in which the glycerin collects on one side of the container while the water stays put on the other side. The density difference between the two substances accounts for the observed separation. The velocity curves slow down as the fluids disperse inside the container, but the increased density of the glycerin side causes it to slow down even more. When the glycerin's velocity is increased to 0.2 m/s, the behavior of mixture changes, resulting in the displacement of water and the appearance of a brush-like shape. It is recommended to conduct a specific research to investigate essential factors like temperature, additives to improve the practical applications of glycerin-water mixing.
Analysis of the Effect of Tortuosity Porous Heatsink on Force Convection Heat Transfer
Authors: Imam Akbar  , Dewi Rawani  , Heriyanto Rusmaryadi  , Martin Luther King  , Pramadhony  , Zulkarnain Fatoni  , Ahmad Malik Abdul Aziz  , Akbar Teguh Prakoso  , Hasan Basri  , Agung Mataram
Published: January 2025

The improvement of performance in modern electronic devices has driven rapid advancements in the field of thermal management. Excessive heating of electronic components can lead to damage and decreased device performance. This research aimed to analyze the effect of tortuosity porous heatsink on force convection heat transfer. Computational fluid dynamics methodology was used to model airflow and the distribution of temperature, velocity, convective heat transfer coefficient, and turbulence kinetic energy (TKE) in heatsinks with varying tortuosity levels. Results show that tortuosity has a positive linear correlation with heatsink surface area and pressure drop. However, it has a negative linear correlation with surface heat transfer coefficient (SHTC). When the tortuosity increases, the surface area increases from 9298.48 mm2 to 12711.93 mm2, and the pressure drop increases from 19.587 Pa to 24.296 Pa. By contrast, the surface heat transfer coefficient decreased significantly from 41.1214 W m-2 K-1 to 30.8454 W m-2 K-1. This study also shows that heatsinks with low tortuosity have a more uniform distribution of temperature, velocity, and TKE, resulting in higher cooling efficiency. Thus, we conclude that tortuosity is an important factor in heatsink design and optimization, and a suitable level of tortuosity should be achieved
The Influence of Leadership and Organizational Culture on Employee Performance Through Employee Loyalty at the Prestasi Cendikia Foundation, Bekasi
Authors: Yahya Surono , Ali Hapzi , Sasanti Munir Ningky
Published: January 2025

The aim of this research is to analyze the influence of leadership and organizational culture on performance through employee loyalty at the Bekasi Prestasi Cendikia Foundation." This research focuses on two independent variables (X), one dependent variable (Y) and one intervening variable (Z). This research is quantitative research using a questionnaire aimed at employee respondents at the Bekasi Prestasi Cendikia Foundation. Sampling in this research was carried out using the saturated sample method with a sample size of 105 respondents. The design used in this research is hypothesis testing using Structural Equation Model (SEM) - Smart PLS 4.1. The results of this research provide an overview of the Smart PLS 4.1. statistical test with the results; 1) Leadership does not have a positive and significant effect on performance with a p-value of 0.928. 2) Organizational culture does not have a positive and significant effect on employee performance with a p-value of 0.289. 3) Leadership has a positive and significant effect on employee loyalty with a p-value of 0.012. 4) Organizational culture has a positive and significant effect on loyalty with a p-value of 0.035. 5) Employee loyalty has a positive and significant effect on employee performance with a p-Value of 0.000. The indirect hypothesis 6) Leadership has a positive and significant effect on performance through the mediation of employee loyalty, getting a P-Value of 0.043. 7) Organizational culture does not have a positive and significant effect on performance through the mediation of Motivation to get a P-Value of 0.063. This research has several limitations, namely that it only focuses on four variables, namely one dependent variable, one intervening variable and two independent variables. The research location is still limited to the at the Bekasi Prestasi Cendikia Foundation and uses a very simple research model. Future researchers are advised to use other variables that can improve performance such as productivity, work quality, efficiency, innovation, attendance rate, error rate, goal achievement, customer satisfaction, competence, task completion rate, responsibility, teamwork and others. It is recommended to expand the research sample or involve a wider study area so that the generalization of the results can be strengthened. The research method is recommended to combine various qualitative and quantitative research methods to obtain a more comprehensive understanding.
Pengaruh Edukasi Dengan Media Video Tentang ASI Eksklusif Melalui Aplikasi Whatsapp Terhadap Ibu Menyusui di Wilayah Kerja Puskesmas Banyuanyar Surakarta
Authors: Wibowo Abdilla Fi Qisthy , Kuswati Kuswati , Istikhomah Henik
Published: January 2025

Exclusive breast milk is breast milk given to a newborn baby in the first six months without any additional food. Lack of knowledge about exclusive breastfeeding has an impact on mothers' low ability to provide exclusive breastfeeding to their babies. Efforts to increase the knowledge and attitudes of breastfeeding mothers regarding exclusive breastfeeding can be done by providing education using video media via the WhatsApp application. To determine the effect of education using video media about Exclusive Breastfeeding via the WhatsApp application on the knowledge and attitudes of breastfeeding mothers in the Banyuanyar Surakarta Community Health Center working area. This research uses a Quasi Experimental Design research design with a One Group Pretest Posttest Design. The sampling technique was purposive sampling with 45 breastfeeding mothers in the working area of ​​the Banyuanyar Community Health Center, Surakarta. Data analysis used the Wilcoxon Test and Paired T Test. The results showed that there was an increase in the average knowledge after the intervention from 13.78 to 19.33 and there was an increase in the average attitude after the intervention from 54.47 to 68.51. The results of the Wilcoxon test showed that there was an increase in knowledge after the intervention, p = 0.000 (p value < 0.05) and the results of the paired T test showed an increase in attitudes after the intervention, p = 0.000 (p value < 0.05). Providing education using video media about exclusive breastfeeding via the WhatsApp application has an impact on the knowledge and attitudes of breastfeeding mothers in the Banyuanyar Surakarta Community Health Center working area.
Perbandingan Efek Core Exercise dan Balance Strategy Exercise Terhadap Kekuatan Otot Tungkai dan Keseimbangan Dinamis pada Lansia
Authors: Shyko Imama Ilham , Prasetyo Awal , Yuniati Renni
Published: January 2025

The main problem that is often experienced by the elderly around the world is falls. where the incidence of falls is one of the factors in death due to injury, the high risk of falls is due to lack of physical activity. this is due to the complex and multipathological risk factors for falls, so it is necessary to practice simple effective and efficient physical activity that can be done alone and does not cost money. This study is an experimental study with a design in the form of Pre and Post Test Control Group Design. This research was conducted at the Potroyudan elderly service centre in Jepara, Central Java. The population of this study was 85 people. Sampling purposive sampling method as many as 40 people divided into 2 groups. Grouping of samples is done randomly / randomly, data analysis using paired sample t test and Independent T Test, The results showed an increase in dynamic balance and leg muscle strength after being given core stability exercise and balance strategy exercise. The results of the comparison of dynamic balance showed no significant difference. The results of the comparison of leg muscle strength showed a significant difference in the increase in leg muscle strength.core exercise is better in increasing leg muscle strength in the elderly
Exploring the Influence of School Climate on Teaching and Learning of Agriculture at Senior Secondary Schools in Eswatini
Authors: Tsikati Alfred , Dlamini Dumisa
Published: January 2025

School climate is the quality and character of school life reflected in its norms, goals, values, interpersonal relationships, teaching and learning practices and organizational structures. No study has been conducted to assess the school climate that exists in Eswatini schools. Thus, this study sought to assess the school climate that exists in senior secondary schools influencing the teaching and learning of agriculture in Eswatini. The study utilized a qualitative research approach employing a phenomenological research design. Purposive sampling was used to sample 25 agriculture teachers in Eswatini. An interview guide was used to collect data in February 2024. Trustworthiness was ensured by addressing issues related to credibility, transferability, dependability and confirmability. Thematic analysis was used to analyse the qualitative data. The study concluded that the climate in Eswatini schools does not fully support the teaching and learning of agriculture. The study therefore, recommended a review of the school policies set by the Ministry of Education and Training; in order to create a conducive school climate that supports the teaching and learning of agriculture in senior secondary schools in Eswatini. The study revealed strategies that can be used to improve the school climate in senior secondary schools needed for the teaching and learning of agriculture in Eswatini.

Keywords: Agriculture Student, Agriculture Teacher, School Climate, Teaching, Learning.
E-Learning Framework Development for Grade 12 Accounting Learners in South African Public High Schools
Authors: Mokoduwe Mosimanegape Elton , Modise Motalenyane Alfred
Published: January 2025

E-learning is growing rapidly and plays a critical role in the transformation of education, allowing users to gather information from endless resources. This study aims to develop a conceptual framework for Grade 12 accounting learners that can enhance teaching and learning in South African public high schools in small townships. The study is driven by the issues faced by local schools and libraries such as having inadequate and outdated accounting learning resources, and other issues such as lack of technology skills, infrastructure and teacher readiness are addressed. A systematic literature review was conducted in this study to analyze and integrate UDL principles and TAM in e-learning to complement the proposed framework for accounting learners. The findings of this study reflect a broader trend in e-learning research, where subject-specific platforms often receive less attention compared to general-purpose E-learning tools. The lack of subject-specific research on E-learning for accounting learners underscores the importance of this study. In conclusion, the findings of this paper provide a robust foundation for the design of a conceptual framework for Grade 12 accounting learners in South African public high schools in small townships.

Keywords: E-Learning, Education, Learners, Accounting
Problems of editorial management for scientific publications. Experiences from an economics and finance journal
Authors: De La Hoz Suárez Betty Auxiliadora , De La Hoz Suárez Aminta Isabel , Manjarres Tete Arleth Esther
Published: January 2025

For the planning and editing of online scientific journals, emphasis should be placed on editorial processes and functions; some of which are peer review and verdict, editing, layout, publication, document preservation, storage system, access to publication, publication indexing, visibility and positioning of the article. This article analyzes the main problems of editorial management for digital scientific publications. It is a descriptive field study, in which a search and recovery of previous published works, such as articles and editorial notes, as well as the systematization of experiences of an Ecuadorian academic journal of economics and finance, with digital format and open access, which starts its activities in 2020, was carried out. The experiences were compiled from information provided by the editor-in-chief of the journal, the coordinator of the scientific committee and a reviewer belonging to the international committee. The results show that there are editorial problems that may arise during the management of the publication of scientific articles, which may be the responsibility of the author, the reviewer or the editor, depending on the case; as well as deficiencies in the use of information and communication technologies to support the management and publication of articles. It is concluded that the success of the publication of scientific papers in academic journals depends on the application of sequential editorial processes and the technological support available to the publisher.
SDSS J100711.74+193056.2: A Candidate Common Motion Substellar Companion to the Nearest B-type Star Regulus
Authors: Mamajek Eric E. , Burgasser Adam J.
Published: January 2025

The L9 dwarf SDSS J100711.74+193056.2 is situated 7

.

°

5 north of the nearest B-type star Regulus (d  = 24.3 ± 0.2 pc), part of a stellar quadruplet. The object is at similar distance (d  =  21.9 ± 1.0 pc) as Regulus, with a 3D separation of

3
.

9

−
0.5

+
0.6

pc (~1.6 tidal radii from Regulus), and shares tangential motion within 2 km s−1, hinting at a physical connection. Near-infrared spectroscopy with Keck/NIRES finds that SDSS J100711.74+193056.2 also has a comparable radial velocity as Regulus A and B, a metallicity similar to Regulus B, and a spectral morphology consistent with the estimated 1–2 Gyr total age of Regulus's close pre-white-dwarf companion. Taken together, these observations indicate that SDSS J100711.74+193056.2 is a very widely separated and potentially physically bound companion to Regulus, with a binding energy and mass ratio comparable to other wide star-brown dwarf systems. It joins a growing list of brown dwarfs at the L-dwarf/T-dwarf transition with independent constraints on physical properties such as age and metallicity.
Discovery and Characterization of an Eccentric, Warm Saturn Transiting the Solar Analog TOI-4994*
Authors: Rodríguez Martínez Romy , Eastman Jason D. , Collins Karen A. , Rodriguez Joseph E. , Charbonneau David , Quinn Samuel N. , Latham David W. , Ziegler Carl , Brahm Rafael , Fairnington Tyler R. , Ulmer-Moll SolÉne , Stassun Keivan G. , Suarez Olga , Guillot Tristan , Hobson Melissa J. , Winn Joshua N. , Kanodia Shubham , Schlecker Martin , Butler R. P. , Crane Jeffrey D. , Shectman Steve , Teske Johanna K. , Osip David , Beletsky Yuri , Battley Matthew P. , Psaridi Angelica , Figueira Pedro , Lendl Monika , Bouchy François , Udry Stéphane , Kunimoto Michelle , Mékarnia Djamel , Abe Lyu , Trifonov Trifon , Tala Pinto Marcelo , Eberhardt Jan , Espinoza Nestor , Henning Thomas , Jordán Andrés , Rojas Felipe I. , Barkaoui Khalid , Relles Howard M. , Srdoc Gregor , Collins Kevin I. , Seager Sara , Shporer Avi , Vezie Michael , Hedges Christina , Mireles Ismael
Published: January 2025

We present the detection and characterization of TOI-4994b (TIC 277128619b), a warm Saturn-sized planet discovered by the NASA Transiting Exoplanet Survey Satellite. TOI-4994b transits a G-type star (V = 12.6 mag) with a mass, radius, and effective temperature of

M

⋆

=
1.00

5

−
0.061

+
0.064

M

⊙

,

R

⋆

=
1.05

5

−
0.037

+
0.040

R

⊙

, and T
eff = 5640 ± 110 K. We obtained follow-up ground-based photometry from the Las Cumbres Observatory and the Antarctic Search for Transiting ExoPlanets telescopes, and we confirmed the planetary nature of TOI-4994b with multiple radial velocity observations from the Planet Finder Spectrograph, CHIRON, High Accuracy Radial velocity Planet Searcher, Fiber-fed Extended Range Optical Spectrograph, and CORALIE instruments. From a global fit to the photometry and radial velocities, we determine that TOI-4994b is in a 21.5 day eccentric orbit (e = 0.32 ± 0.04) and has a mass of

M

P

=
0.28

0

−
0.034

+
0.037

M

J

, a radius of

R

P

=
0.76

2

−
0.027

+
0.030

R

J

, and a Saturn-like bulk density of

ρ
p

=
0.7

8

−
0.14

+
0.16

g

cm

-
3

. We find that TOI-4994 is a potentially viable candidate for follow-up stellar obliquity measurements. TOI-4994b joins the small sample of warm Saturn analogs and thus sheds light on our understanding of these rare and unique worlds.
Atmospheric Distribution and Escape of Odd Nitrogen on Mars
Authors: Gu 顾 Hao 浩 , Wu 吴 Xiaoshu 晓姝 , Cui 崔 Jun 峻 , Huang 黄 Xu 旭 , Li 李 Wenlong 文龙 , Zhao 赵 Jinjin 金锦 , Li 李 Lei 磊
Published: January 2025

The total nitrogen budget in the Martian upper atmosphere is significantly contributed by the presence of odd nitrogen, mainly in the form of NO and ground-state or excited-state N. The distribution of these species can be effectively probed by airglow emission on Mars, and understanding such a distribution is crucial for unveiling the thermal balance in the Martian upper atmosphere. In this study, we construct a sophisticated 1D photochemical model that also incorporates vertical diffusion and photoelectron production and transport. Such a model is used for obtaining the atmospheric distribution of both NO and different electronic states of atomic N on the dayside of Mars. Our study reproduces well the available measurements of relevant species in the combined Martian upper atmosphere and ionosphere, disentangling various chemical pathways in their contributions to odd nitrogen production and destruction. In addition, the photochemical model is combined with a Monte Carlo kinetic model to derive the dayside total N escape rate to be 3.3 × 1023 s−1 driven by photochemistry. This study corroborates previous findings that N2 photolysis and N

2

+

dissociative recombination are the main contributors to the photochemical escape of N on Mars. Moreover, it underscores the significant role of photochemistry in shaping the long-term evolution of the Martian atmosphere.
From Halos to Galaxies. VI. Improved Halo Mass Estimation for SDSS Groups and Measurement of the Halo Mass Function
Authors: Zhao Dingyi , Peng Yingjie , Jing Yipeng , Yang Xiaohu , Ho Luis C. , Renzini Alvio , Gallazzi Anna R. , Lyu Cheqiu , Maiolino Roberto , Dou Jing , Gao Zeyu , Gu Qiusheng , Mannucci Filippo , Mo Houjun , Wang Bitao , Wang Enci , Wang Kai , Wang Yu-Chen , Xu Bingxiao , Yuan Feng , Zhu Xingye
Published: January 2025

In ΛCDM cosmology, galaxies form and evolve in their host dark matter (DM) halos. Halo mass is crucial for understanding the halo–galaxy connection. The abundance-matching (AM) technique has been widely used to derive the halo masses of galaxy groups. However, the quenching of the central galaxy can decouple the coevolution of its stellar mass and DM halo mass. Different halo assembly histories can also result in significantly different final stellar masses of the central galaxies. These processes can introduce substantial uncertainties into the halo masses derived from the AM method, particularly leading to a systematic bias between groups with star-forming centrals (blue groups) and passive centrals (red groups). To improve this, we have developed a new machine learning (ML) algorithm that accounts for these effects and is trained on simulations. Our results show that the ML method eliminates the systematic bias in the derived halo masses for blue and red groups and is, on average, ~one-third more accurate than the AM method. With careful calibrations of observable quantities from simulations and observations from the Sloan Digital Sky Survey (SDSS), we apply our ML model to the SDSS groups to derive their halo masses down to 1011.5
M
⊙ or even lower. The derived SDSS group halo mass function agrees well with the theoretical predictions, and the derived stellar-to-halo mass relations for both the red and blue groups match well with those obtained from direct weak-lensing measurements. These new halo mass estimates enable more accurate investigation of the galaxy–halo connection and the role of halos in galaxy evolution.
Repeating Partial Tidal Encounters of Sun-like Stars Leading to Their Complete Disruption
Authors: Liu 刘 Chang 畅 , Yarza Ricardo , Ramirez-Ruiz Enrico
Published: January 2025

Stars grazing supermassive black holes on bound orbits may produce periodic flares over many passages, known as repeating partial tidal disruption events (TDEs). Here, we present 3D hydrodynamic simulations of Sun-like stars over multiple tidal encounters. The star is significantly restructured and becomes less concentrated as a result of mass loss and tidal heating. The vulnerability to mass loss depends sensitively on the stellar density structure, and the strong correlation between the fractional mass loss ΔM/M
* and the ratio of the central and average density

ρ

c

/

ρ

¯

, which was initially derived in disruption simulations of main-sequence stars, also applies for stars strongly reshaped by tides. Over multiple orbits, the star loses progressively more mass in each encounter and is doomed to a complete disruption. Throughout its lifetime, the star may produce numerous weak flares (depending on the initial impact parameter), followed by a couple of luminous flares whose brightness increases exponentially. Flux-limited surveys are heavily biased toward the brightest flares, which may appear similar to the flare produced by the same star undergoing a full disruption on its first tidal encounter. This places new challenges on constraining the intrinsic TDE rates, which need to take repeating TDEs into account. Other types of stars with different initial density structures (e.g., evolved stars with massive cores) follow distinct evolution tracks, which might explain the diversity of the long-term luminosity evolution seen in recently uncovered repeaters.
Star-forming Nuclear Clusters in Dwarf Galaxies Mimicking Active Galactic Nucleus Signatures in the Mid-infrared
Authors: Sturm Megan R. , Hayes Bayli , Reines Amy E.
Published: January 2025

Effectively finding and identifying active galactic nuclei (AGNs) in dwarf galaxies is an important step in studying black hole formation and evolution. In this work, we examine four mid-infrared (IR)-selected AGN candidates in dwarf galaxies with stellar masses between M
⋆ ~ 108 and 109
M
⊙ and find that the galaxies are host to nuclear star clusters (NSCs) that are notably rare in how young and massive they are. We perform photometric measurements on the central star clusters in our target galaxies using Hubble Space Telescope optical and near-IR imaging and compare their observed properties to models of stellar population evolution. We find that these galaxies are host to very massive (~107
M
⊙), extremely young (≲8 Myr), and dusty (0.6 ≲ A
v ≲ 1.8) NSCs. Our results indicate that these galactic nuclei have ongoing star formation, are still at least partially obscured by clouds of gas and dust, and are most likely producing the extremely red AGN-like mid-IR colors. Moreover, prior work has shown that these galaxies do not exhibit X-ray or optical AGN signatures. Therefore, we recommend caution when using mid-IR color–color diagnostics for AGN selection in dwarf galaxies, since, as directly exemplified in this sample, they can be contaminated by massive star clusters with ongoing star formation.
ALMA Spectral Survey of an Eruptive Young Star, V883 Ori (ASSAY). II. Freshly Sublimated Complex Organic Molecules in the Keplerian Disk
Authors: Jeong Jae-Hong , Lee Jeong-Eun , Lee Seonjae , Baek Giseon , Kang Ji-Hyun , Lee Seokho , Kim Chul-Hwan , Yun Hyeong-Sik , Aikawa Yuri , Herczeg Gregory J. , Johnstone Doug , Cieza Lucas
Published: January 2025

We present an investigation of complex organic molecules (COMs) in the spatially resolved Keplerian disk around V883 Ori, an eruptive young star, based on a spectral survey carried out with the Atacama Large Millimeter/submillimeter Array in Band 6 (220.7−274.9 GHz). We identified about 3700 molecular emission lines and discovered 23 COMs in the disk. We estimated the column densities of the COMs detected, using the iterative LTE line-fitting method. According to our analyses, using only optically thin lines is critical to deriving the reliable column densities of COMs. Therefore, covering a large frequency range is important for the studies of COMs. The most distinct phenomenon found from the spectra of the V883 Ori disk is that nitrogen-bearing COMs other than CH3CN are missing, whereas various oxygen-bearing COMs, except for the CH2OH-bearing molecules, are detected. The missing CH2OH-bearing COMs may indicate the warm water-ice dominant environment for forming COMs. We compared our results with various objects in different evolutionary stages, from Class 0 hot corinos to a solar system comet 67P/Churyumov-Gerasimenko, to examine the effect of evolution on the COM compositions. In general, the COM abundances relative to methanol in V883 Ori are higher than in the hot corinos and hot cores, while they are comparable to the cometary values. This may indicate the planet-forming material chemically evolves in the disk midplane after being accreted from the envelope. In addition, as found in the comet 67P/Churyumov-Gerasimenko, nitrogen might also be trapped as ammonium salt within the dust grains in the V883 Ori disk.
Magnetic Activity of TESS Objects Observed in the LAMOST Medium-resolution Spectral Survey
Authors: Su Tianhao , Zhang Li-yun , Misra Prabhakar , Han Xianming L. , Wang Yinpeng , Li Wenjie , Zhu Zhongzhong , Pi Qingfeng , Lu Hongpeng
Published: January 2025

A combination of spectroscopic and photometric observations provides an excellent data sample for studying stellar chromospheric activity. We have combined LAMOST medium-resolution spectra with TESS 2 minute light curves and extracted over 530,000 spectra and 110,000 light curves from more than 40,000 stars. We have quantified the Hα line intensity in each spectrum and found that 38,659 spectra from 7002 stars exhibited excess Hα emission and that the intensity of stellar chromospheric activity increases with later spectral types. We also discovered that the boundary value between the saturated and unsaturated regions of chromospheric activity for different spectral type stars is around Ro = 0.1. By analyzing the TESS light curves, we identified 31,539 flare events from 4120 stars. Through these flare events, we determined that the flare-frequency proportion of stars increases with later spectral types. We have found that the power-law index of the flare-frequency distribution for F-, G-, K-, and M-type stars is around 2.0, while that for A-type stars is 1.3. Additionally, we observed that the amplitude of brightness variations caused by modulation due to starspot coverage (R
eff) is positively correlated with both the flare intensity and intensity of chromospheric activity and that the chromospheric activity was generally stronger in flare stars as compared to nonflare stars. We also found that within 300 pc, the proportion of chromospherically active stars and flare stars decreases with increasing distance from the Galactic disk. Finally, we discovered six flare events from the Hα variation and estimated their energies.
Metallicity Dependence of Giant Planets around M Dwarfs
Authors: Gan Tianjun , Theissen Christopher A. , Wang Sharon X. , Burgasser Adam J. , Mao Shude
Published: January 2025

We investigate the stellar metallicity ([Fe/H] and [M/H]) dependence of giant planets around M dwarfs by comparing the metallicity distribution of 746 field M dwarfs without known giant planets with a sample of 22 M dwarfs hosting confirmed giant planets. All metallicity measurements are homogeneously obtained through the same methodology based on the near-infrared spectra collected with a single instrument SpeX mounted on the NASA Infrared Telescope Facility. We find that (1) giant planets favor metal-rich M dwarfs at a 4σ–5σ confidence level, depending on the band of spectra used to derive metallicity; (2) hot (a/R
*≤20) and warm (a/R
* > 20) Jupiters do not show a significant difference in the metallicity distribution. Our results suggest that giant planets around M and FGK stars, which are already known to prefer metal-rich hosts, probably have a similar formation channel. In particular, hot and warm Jupiters around M dwarfs may have the same origin as they have indistinguishable metallicity distributions. With the refined stellar and planetary parameters, we examine the stellar metallicities and the masses of giant planets where we find no significant correlation. M dwarfs with multiple giant planets or with a single giant planet have similar stellar metallicities. Mid-to-late type M stars hosting gas giants do not show an apparent preference to higher metallicities compared with those early M dwarfs with gas giants and field M dwarfs.
Magnetic Reconnection: An Alternative Explanation of Radio Emission in Galaxy Clusters
Authors: Ghosh Subham , Bhat Pallavi
Published: January 2025

Observations of galaxy clusters show radio emission extended over almost the system scale, necessitating mechanisms for particle acceleration. Previous models for acceleration, such as diffusive shock acceleration and that due to turbulence, can fall short in terms of efficiency. In this Letter, we propose the possibility of acceleration via magnetic reconnection. In particular, we invoke the plasmoid instability, which has been previously applied to understand particle energization in high-energy systems. Turbulence in galaxy clusters leads to fluctuation dynamos that are known to generate magnetic field structures consisting of sharp reversals. These form natural sites of reconnection. We perform particle-in-cell simulations of the plasmoid instability in collisionless and nonrelativistic plasmas. We show that the resulting electron energy spectra have power-law indices that are consistent with those inferred from observations. Our estimates show that the acceleration timescales are much smaller than the lifetime of the reconnecting magnetic structures indicating the feasibility of our model. The synchrotron radio luminosity estimate is about 1041 erg s−1, agreeing with observations. Finally, we find that the maximum achievable Lorentz factor can go up to 105 indicating that acceleration due to magnetic reconnection is a promising avenue for understanding the origin of nonthermal emission in galaxy clusters.
Implications of Differentiated Late Accretion for the Volatile Inventory of the Bulk Silicate Earth
Authors: Grewal Damanveer S. , Manilal Varun
Published: January 2025

Earth is believed to have acquired its highly siderophile element (HSE) inventory through the late accretion of ∼0.3%–0.5% of its mass in chondrite-like materials, following the main stage of its growth. Late accretion, particularly if it originated from the outer solar system, could have significantly contributed to the bulk silicate Earth’s (BSE = mantle + crust + hydrosphere + atmosphere) carbon–nitrogen–hydrogen (C–N–H) inventory. However, recent studies, noting differences between the HSE inventory of the Earth and Moon’s mantle, suggest that relatively large lunar-sized differentiated impactors, rather than small chondritic projectiles, delivered HSEs to Earth’s mantle during late accretion. The implications of a differentiated late accretion event for the BSE’s C–N–H inventory remain unclear. In this study, we modeled the equilibrium partitioning of highly volatile C–N–H and moderately volatile sulfur–selenium–tellurium (S–Se–Te) between the atmosphere, magma ocean (MO), and core of lunar-sized or slightly larger impactors. The impactor’s MO-degassed atmosphere contained most of its C–N–H inventory, whereas almost all of the S–Se–Te was present in its core or mantle. Given the low escape velocity of lunar-sized impactors, the MO-degassed atmosphere was likely dissipated quickly after core formation. As a result, in contrast to S–Se–Te, the contribution of differentiated late accretion to BSE’s C–N–H inventory was limited, irrespective of its inner or outer solar system origin. The C–N–H-depleted nature of differentiated objects suggests that most of BSE’s highly volatile inventory was delivered by primitive chondritic materials toward the final stages of Earth’s accretion, before the Moon-forming event.
A new remarkable cimicoid genus and species (Hemiptera, Heteroptera, Cimicomorpha) from mid-Cretaceous Burmese amber, with implications for its aberrant male genitalia
Authors: Yamada Kazutaka , Yamamoto Shûhei , Takahashi Yui
Published: January 2025

A new genus and species of cimicoid true bug, Ecpaglocoris ditomeus Yamada & Yamamoto, gen. et sp. nov., is described and illustrated from mid-Cretaceous (Cenomanian–Albian) amber in the Kachin State of northern Myanmar (Burma). This new fossil genus and species is reminiscent of members of Anthocoridae by the strongly flattened and elongated body, four-segmented labium, distinct costal fracture and presence of fossula spongiosa on fore tibiae, but should not be ascribed to this family. The new taxon cannot be placed in any extant cimicoid families, based upon hemelytral, male genital and other morphological structures. Based on the hemelytral membrane venation and presence of dorsal laterotergites on abdominal segments I to VIII, it can be assumed that this new genus belongs to the extinct family Vetanthocoridae. Ecpaglocoris ditomeusgen. et sp. nov. has aberrant male genitalia characterised by sickle-shaped left and right parameres and grooves running throughout the paramere. This characteristic indicates that traumatic insemination occurred in this genus. The peculiar combination of male genital characteristics seen in Ecpaglocorisgen. nov. prevents its placement in any of the extant cimicoid families.
Coexistence of Oligocene toothed and baleen-assisted mysticetes in the northwestern Pacific
Authors: Tsai Cheng-Hsiu , Kimura Toshiyuki , Hasegawa Yoshikazu
Published: January 2025

Oligocene mysticetes display an unparalleled diversity and morphological disparity in the evolutionary history of Mysticeti. However, their paleoecological aspects, such as the patterns of coexistence of different morphotypes, remain poorly explored. Here we describe an aetiocetid (toothed mysticete) from the Jinnobaru Formation (lower upper Oligocene, about 28 million years ago) of Umashima Island, Kitakyushu, Japan. Our description of a toothed mysticete from the Oligocene of Umashima exemplifies the coexistence of toothed and baleen-assisted mysticetes in the northwestern Pacific. Hopefully, new finds of Oligocene mysticetes will lead to a well-sampled dataset for analyzing this and other related paleoecological traits to understand the demise of “archaic” Oligocene mysticetes and the subsequent rise of the modern-looking baleen-bearing whales in Miocene times.
A new species of Palaeohypotodus Glückman, 1964 (Chondrichthyes, Lamniformes) from the lower Paleocene (Danian) Porters Creek Formation, Wilcox County, Alabama, USA
Authors: Ebersole Jun A. , Cicimurri David J. , Harrell Jr. T. Lynn
Published: January 2025

The historic collection of the Geological Survey of Alabama includes several fossil shark specimens that were recovered from the lower Paleocene Porters Creek Formation in southwestern Alabama, USA. Among these specimens are 17 teeth that we herein recognize as a new species within the extinct Paleogene genus, Palaeohypotodus. Detailed examination of these individual teeth, coupled with analyses of the dentitions of various extant lamniform sharks, allowed us to confirm monognathic and dignathic heterodonty within Palaeohypotodus. We identified upper and lower anterior and lateral tooth files that can be differentiated from one another by minor variations in morphology. Additionally, numerous isolated teeth from other Danian exposures in Alabama and Arkansas, USA, enhance our understanding of the composition of the dentition and ontogenetic heterodonty of both the new species and the genus as a whole.
First 3D reconstruction of a forewing of a fossil Orthoptera: Interpreting the venation pattern in the smallest known cricket with a stridulatory apparatus, †Picogryllus carentonensis (Orthoptera, Grylloidea, Oecanthidae)
Authors: Ferreira Jules , Josse Hugo , Denadai de Campos Lucas , Nel André , Desutter-Grandcolas Laure
Published: January 2025

Fossil insects are valuable indicators of the evolutionary history of the clades to which they belong. According to their state of preservation, fossil insects are often partially described for key morphological characters, such as forewing venation in crickets (Orthoptera, Grylloidea). In parallel, the use of 3D microtomography is increasingly becoming common for studying some fossils, which allowed here the precise reconstruction and interpretation of the venation pattern in the smallest known cricket with a stridulatory apparatus, †Picogryllus carentonensis, found in opaque amber. The 3D reconstructions have revealed the general structure of the venation of the forewing and have enabled the identification of all its veins and cells, validating its similarity with that of extant crickets. Putative homologies are established according to previous studies, and some particularities are observed, such as the presence of two crossveins in the mirror, a rare feature in extant crickets that is discussed in the frame of cricket venation evolution. These findings highlight the importance of 3D microtomography as a powerful tool for examining fossil insects and also provide crucial information for taxonomic identification and evolutionary studies, offering a validated morphological basis for future phylogenetic analyses incorporating fossils.
Cauca: megafaunal and felid fossils (Mammalia) from a Pleistocene site in northwest Venezuela
Authors: Carrillo-Briceño Jorge Domingo , Ruiz-Ramoni Damián , Sánchez Rodolfo , Jaimes Arturo , Chávez-Aponte Edwin , Prevosti Francisco Juan , Segura Valentina , Carlini Alfredo Armando , Garbé Lisa , Tombret Olivier , Zazzo Antoine , Sánchez-Villagra Marcelo Ricardo
Published: January 2025

Numerous surveys and three excavation and surface collection field seasons resulted in the discovery of numerous megafaunal remains and that of a medium-sized felid in a new site located on the coastal plain of the Gulf of Venezuela, in Western Falcón State. The faunal assemblage is represented by South American natives such as megatheres (cf. Eremotherium laurillardi), an indeterminate mylodontid and a glyptodont (probably related to Glyptotherium) and Nearctic representatives such as gomphotheres (Notiomastodon platensis), equids (Equus sp.) and a feline (Felidae cf. Leopardus pardalis), providing novel information for the distribution of some of these mammals. Radiocarbon indicates that this deposit is at least 40,000 years old. Lithic artefacts of a kind reported for other Pleistocene sites in the region document the presence of humans in Cauca, but as these cultural remains were found on the surface, their association with the fauna is uncertain.
The Eocene to Oligocene boundary and paleoclimatic indications based on calcareous nannofossils of Tonasa Formation, South Sulawesi, Indonesia
Authors: Farida Meutia , Jaya Asri , Ahmad Asmita , Nugraha Jimmi
Published: January 2025

The biostratigraphy of the Tonasa Formation in the Jeneponto Regency of South Sulawesi, Indonesia, is still poorly known, and there are barren ages, such as much of the Oligocene to Early Miocene. The Tonasa Formation is well exposed along the coast of the Jeneponto Regency, in which the Karama area consists of the most important outcrops of this formation which in this area consists of interbedded marl and limestone. Our study focuses on the biostratigraphy of the Karama area section A based on nannofossil. Samples were collected by measured stratigraphy methods and then subjected to investigation using smear slides. The assemblages of species were determined by semiquantitative analysis. Data analysis obtained three nannofossil datums (boundaries): The First Occurrence (FO) of Sphenolithus pseudoradians NP19/NP20), the First Occurrence of Sphenolithus distentus (CP.16/CP.17), and the Last Occurrence (LO) Sphenolithus predistentus (NP.23/NP.24. The zonal boundary was determined based on calcareous nannoplankton; the Late Eocene to Middle Oligocene boundary of the Tonasa Formation was found in this section. Interestingly, throughout this period, the marker species in this section is Sphenolithus. In addition, the presence of Sphenolithus, Discoaster, and Zygrhablithus bijugatus indicated that the basin was in warm water condition.
Essential oils – a review of the natural evolution of applications and some future perspectives
Authors: Ivanova Stanislava , Gvozdeva Yana , Staynova Radiana , Grekova-Kafalova Daniela , Nalbantova Vanya , Benbassat Niko , Koleva Nina , Ivanov Kalin
Published: January 2025

Since ancient times, essential oils (EOs) have been used, thoroughly explored, and regarded as products of great importance for humanity. Currently, EOs represent not only an important part of the contemporary pharmaceutical and cosmetic industry but are also considered as sources for novel drug candidates. The article discusses the applications of EOs in historical terms, the current applications, and the future perspectives. Although there are many studies that involve EOs, the therapeutic potential of EOs is not fully investigated. In the next decades it is highly likely that some compounds, isolated from EOs, could be included in the composition of novel drug candidates with targets in neurology, cardiology, or oncology. Moreover, EOs represent important key points in the development of novel environmentally friendly preservatives and pesticides.
Morphometric parameters of seeds as a practical method for identifying rare species of the genus Tulipa L. (Liliaceae) from East Kazakhstan region
Authors: Sumbembayev Aidar A. , Lagus Olga , Danilova Alevtina N. , Rewicz Agnieszka , Nowak Sławomir
Published: January 2025

The genus Tulipa includes some of the most important ornamental plants. The aim of this work was to study the seed morphology of Tulipa species from East Kazakhstan, including seed coat structure. An analysis focused on five taxa from various natural environmental conditions. A total of 31 tulip populations were studied to establish morphological variability. Preliminary analyses of the importance of habitat-related ecological factors have been carried out. The results of this study provide new qualitative characteristics for distinguishing closely related species and are discussed in relation to their systematic relationships. The structure of the seed coat was studied by Scanning Electron Microscopy; however, the results did not show significant variability. An identification key to determine the species of tulips in East Kazakhstan is proposed.
Adopter une approche sociodémographique pour repenser les migrations
Authors: Paté Noémie , Paté Noémie
Published: January 2025

L’article explore les migrations à travers une perspective sociodémographique pour dépasser les idées reçues et les approches simplistes souvent véhiculées par les discours politiques et médiatiques. Il s’intéresse à la perception dominante d’une « submersion migratoire » et démontre que la migration est un phénomène historique et constant. Les migrations internationales restent stables, avec une très grande majorité de flux internes et régionaux. Le texte cherche à mettre en évidence l’importance d’une approche basée sur des données objectives, soulignant que les populations migrantes représentent une dimension essentielle de nos économies comme de nos tissus sociaux. L’article appelle enfin à repenser les politiques migratoires en tenant compte des réalités climatiques et sociales.
Une supériorité en partage. Genèse et perpétuation d’une association de dirigeants d’entreprises dans le monde de la pâtisserie de boutique
Authors: Collas Thomas
Published: January 2025

L’article analyse la genèse, le recrutement et les activités d’une association de dirigeants d’entreprises dans le monde de la pâtisserie de boutique, association réservée à ce que les fondateurs désignent comme des « professionnels d’élite ». L’article soutient que l’hybridation entre une communauté de pratique – dédiée au partage de connaissances liées à la direction et au développement de petites entreprises – et un collectif affirmant constituer une élite s’opère, d’une part, par la prise en compte de la localisation des candidats afin d’éviter la concurrence entre membres et, d’autre part, par la création et l’entretien de revendications de supériorité par rapport à d’autres boutiques de pâtisserie sur les marchés locaux ainsi délimités.