bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aplicativos móveis para a aprendizagem de Libras: uma análise das opiniões de seus usuários
Authors: Pereira Batista Jerlan , Rossi Stumpf Marianne 
Published: June 2024

O estudo apresenta discussões em torno da tecnologia e aprendizagem da Língua Brasileira de Sinais-Libras. O seu objetivo geral consiste em: discutir as potencialidades de aplicativos móveis voltados para a aprendizagem de Libras encontrados no Google Play Store por meio das opiniões de usuários. Atualmente, tem-se percebido uma larga procura em aprender Libras por meio de cursos de extensão, no contato com a comunidade surda em diferentes espaços, nas instituições de ensino. Todavia, muitas pessoas não conseguem frequentar estes espaços, o que as leva a buscar outros meios de aprendizagem e encontram nos aplicativos móveis, uma alternativa para adquirir esse conhecimento. Diante disso, esta pesquisa de abordagem qualitativa, do tipo exploratória, analisa as opiniões de usuários de aplicativos móveis voltados a aprendizagem de Libras encontrados no Google Play Store. Os resultados demonstram que os aplicativos apresentam pontos positivos e negativos aos usuários. Além disso, há situações linguísticas nas narrativas dos usuários que carecem de ser discutidas, como ausência na variação dos sinais e o uso de português sinalizado nos aplicativos analisados.

Palavras-chave: Libras. Aplicativos. Tecnologia móvel. Aprendizagem.
Pengaruh Pendekatan Kontekstual terhadap Kemampuan Berpikir Kritis Matematis Peserta Didik SMP
Authors: Helma Lia Sapitri  , Zulhendri Zulhendri , Kasman Ediputra  
Published: June 2024

Penelitian dilatar belakangi oleh kurangnya kemampuan berpikir kritis peserta didik ketika pembelajaran matematika. Hal tersebut ditandai dengan adanya perasaan takut atau khawatir yang dipunyai peserta didik kelas VII SMP Negeri 3 Bangkinang. Salah satu solusi untuk mengatasi masalah ini ialah dengan mengimplementasikan pendekatan kontekstual. Tujuan penelitian ini untuk menguji pendekatan kontekstual dapat berpengaruh terhadap berpikir kritis matematis peserta didik kelas VII SMP Negeri 3 Bangkinang. Jenis penelitian yang digunakan dalam penelitian ini ialah eksperimen semu dengan desain randomized control group pretest-posttest. Subjek penelitian terdiri dari kelas VII A yang berjumlah 24 peserta didik dan kelas VII C yang berjumlah 25 peserta didik. Teknik sampel yang digunakan ialah purposive sampling. Teknik pengumpulan data yang digunakan yaitu menggunakan soal tes matematika berbentuk uraian. Berdasarkan hasil uji hipotesis dapat disimpulkan bahwa pendekatan kontekstual berpengaruh terhadap berpikir kritis matematis peserta didik kelas VII SMP Negeri 3 Bangkinang. Hal tersebut dapat dibuktikan melalui uji Hipotesis dengan Independent Sample t-test.
Effect of Sales, Production Cost and Operating Cost on Net Profit
Authors: Ningrum Rafika Resti Astri , Yulia Iis Anisa , Wahidhani Eha 
Published: June 2024

This study aims to determine the effect of sales, production cost, and operating costs on net profit either partially or simultaneously. The analytical method used is panel data linear regression with the dependent variable, namely net income, and the independent variables, namely sales, production costs and operating costs. The result of the research show that sales, production cost and operating costs have an effect on net income either particially or simultaneously.

Keywords: Sales, Production Costs, Operating Costs and Net Income
The Utility of Infrasound in Global Monitoring of Extraterrestrial Impacts: A Case Study of the 2008 July 23 Tajikistan Bolide
Authors: Silber Elizabeth A. 
Published: June 2024

Abstract
Among the various observational techniques used for the detection of large bolides on a global scale is a low-frequency sound known as infrasound. Infrasound, which is also one of the four sensing modalities used by the International Monitoring System, offers continuous global monitoring and can be leveraged for planetary defense. Infrasonic records can provide an additional dimension for event characterization and a distinct perspective that might not be available through any other observational method. This paper describes the infrasonic detection and characterization of the bolide that disintegrated over Tajikistan on 2008 July 23. This event was detected by two infrasound stations at distances of 1530 and 2130 km. Propagation paths to one of the stations were not predicted by the model, despite being clearly detected. The presence of the signal is attributed to the acoustic energy being trapped in a weak but leaky stratospheric AtmoSOFAR channel. The infrasound signal analysis indicates that the shock originated at the point of the main breakup at an altitude of 35 km. The primary mode of the shock production of the signal detected at the two stations was a spherical blast resulting from the main gross fragmentation episode. The energy estimate, based on the signal period, is 0.17–0.51 kt of TNT equivalent, suggesting a mass of 6.6–23.5 tons. The corresponding object radius, assuming the chondritic origin, was 0.78–1.18 m.
A Reference Meteor Magnitude for Intercomparable Fluxes
Authors: Moorhead Althea V. , Vida Denis , Brown Peter G. , Campbell-Brown Margaret D. 
Published: June 2024

Abstract
The rate at which meteors pass through Earth’s atmosphere has been measured or estimated many times over; existing flux measurements span at least 12 astronomical magnitudes, or roughly five decades in mass. Unfortunately, the common practice of scaling flux to a universal reference magnitude of +6.5 tends to collapse the magnitude or mass dimension. Furthermore, results from different observation networks can appear discrepant due solely to the use of different assumed population indices, and readers cannot resolve this discrepancy without access to magnitude data. We present an alternate choice of reference magnitude that is representative of the observed meteors and minimizes the dependence of flux on population index. We apply this choice to measurements of recent Orionid meteor shower fluxes to illustrate its usefulness for synthesizing independent flux measurements.
Optical Spectropolarimetric Variability Properties in Blazars PKS 0637–75 and PKS 1510–089
Authors: Podjed Stephanie A. , Hickox Ryan C. , Isler Jedidah C. , Böttcher Markus , Schutte Hester M. 
Published: June 2024

Abstract
Spectropolarimetry is a powerful tool to investigate the central regions of active galactic nuclei (AGNs) as polarization signatures are key to probing magnetic field structure, evolution, and the physics of particle acceleration in jets. Optical linear polarization of blazars is typically greater than a few percent, indicating the emission is dominated by nonthermal synchrotron radiation, while polarization less than a few percent is common for other type 1 AGNs. We present a spectropolarimetric study of PKS 0637–75 and PKS 1510–089 to determine how the head-on orientation of a jet and dominant emission processes influence polarimetric variations in the broad lines and continuum. Observations were obtained biweekly from the Robert Stobie Spectrograph on the Southern African Large Telescope. Variability in the continuum polarization is detected for both PKS 0637–75 and PKS 1510–089, with a total average level of 2.5% ± 0.1% and 7.5% ± 0.1%, respectively. There is no clear polarization in the broad Balmer emission lines and weak polarization in Mg ii as the average level across all observations is 0.2% ± 0.1% for Hβ, 0.2% ± 0.3% for Hγ, and 0.6% ± 0.2% for Mg ii. We find that polarization measurements confirm the conclusions drawn from spectral energy distribution modeling of the disk–jet contributions to the emission as optical polarization and time variability for PKS 0637–75 are shown to be dominated by accretion disk emission while those of PKS 1510–089 are due to both disk and jet emission, with greater jet contribution during flaring states.
Role of Polycyclic Aromatic Hydrocarbons with Edge Defects in Explaining Astronomical Infrared Emission Observations
Authors: Ricca A. , Roser J. E. , Boersma C. , Peeters E. , Maragkoudakis A. 
Published: June 2024

Abstract
A systematic study was performed on the spectral properties of polycyclic aromatic hydrocarbons (PAHs) with edge defects using harmonic density functional theory calculations. Their potential astronomical relevance was assessed through direct comparison with NIRSpec and MIRI-MRS spectra of the atomic photodissociation region of the Orion Bar from the JWST Early Release Science PDRs4All program. It is found that the astronomical 6.2 μm PAH emission band, including its blue side, is well reproduced by PAHs with edge defects, when taking into account the effects of polarization in the computations, and without a need for PAHs that contain nitrogen. Small neutral PAHs with edge defects explain the blue wing of the 3.3 μm band. A low number of edge defects is required to reproduce the 8.6 and 11.2 μm band profiles, while the 11.0 + 11.2/12.7 μm band intensity ratio is a measure for the number of edge defects. A blind database fit to the Orion Bar spectrum reproduces the 6–15 μm region with an error of 9.9% and shows a clear delineation of charge, with the 6–10 μm PAH bands being carried by PAH cations and the 10–15 μm region by predominantly neutral PAHs. The contribution of anions is negligible. Armchair PAHs fit the 12.7 μm band, simultaneously producing a very weak broad emission feature centered at 3.225 μm. Zigzag PAHs fit the 11.2 μm band. It is concluded that PAHs with a low number of edge defects, in addition to armchair and zigzag PAHs, all contribute to the observed interstellar infrared emission.
Stellar Abundances at the Center of Early-type Galaxies with Fine Structure
Authors: Barth Nicholas , Privon George C. , Ezzeddine Rana , Evans Aaron S. , Treister Ezequiel 
Published: June 2024

Abstract
Our understanding of early-type galaxies (ETGs) has grown in the past decade with the advance of full-spectrum fitting techniques used to infer the properties of the stellar populations that make up the galaxy. We present ages, central velocity dispersions, and abundance ratios relative to Fe of C, N, O, Mg, Si, Ca, Ti, Cr, Mn, Co, Ni, Cu, Sr, Ba, and Eu, derived using full-spectrum fitting techniques for three ETGs, NGC 2865, NGC 3818, and NGC 4915. Each of these three galaxies were selected because they have optical, disturbed structures (fine structure) that are linked to major merger events that occurred 1, 7, and 6 Gyr ago, respectively. Two of the ETGs, NGC 3818 and NGC 4915, show chemical signatures similar to ETGs without fine structure, which is consistent with a gas-poor merger of elliptical galaxies in which substantial star formation is not expected. For NGC 2865, we find a statistically higher abundance of Ca (an α element) and Cr and Mn (Fe-peak elements). We show that for NGC 2865, a simple gas-rich merger scenario fails to explain the larger abundance ratios compared to ETGs without fine structure. These three ETGs with fine structure exhibit a range of abundances, suggesting ETGs with fine structure can form via multiple pathways and types of galaxy mergers.
Frozen-field Modeling of Coronal Condensations with MPI-AMRVAC. I. Demonstration in Two-dimensional Models
Authors: Zhou Yuhao , Li Xiaohong , Keppens Rony 
Published: June 2024

Abstract
Large-scale coronal plasma evolutions can be adequately described by magnetohydrodynamics (MHD) equations. However, full multidimensional MHD simulations require substantial computational resources. Given the low plasma β in the solar corona, in many coronal studies, it suffices to approximate the magnetic field to remain topologically fixed and effectively conduct one-dimensional (1D) hydrodynamic (HD) simulations instead. This approach is often employed in studies of coronal loops and their liability to form condensations related to thermal instability. While 1D HD simulations along given and fixed field line shapes are convenient and fast, they are difficult to directly compare with multidimensional phenomena. Therefore, it is more convenient to solve volume-filling, multidimensional versions of the MHD equations where we freeze the magnetic field, transforming it into frozen-field HD (ffHD) equations for simulation. We have incorporated this ffHD module into our open-source MPI-AMRVAC code and tested it using a two-dimensional (2D) evaporation–condensation model to study prominence formation due to radiative losses. The 2D ffHD results are compared with those from actual 2D MHD and pseudo-2D HD simulations, analyzing the differences and their causes. Pseudo-2D studies account for the known flux tube expansion effects. Overall, the performance of 2D ffHD is close to that of 2D MHD and pseudo-2D HD. The 2D tests conducted in this paper will be extended in follow-up studies to 3D simulations based on analytical or observational approaches.
Finding Candidate TeV Halos among Very-high-energy Sources
Authors: Zheng Dong , Wang Zhongxiang 
Published: June 2024

Abstract
We search for possible pulsar TeV halos among the very-high-energy (VHE) sources reported in different VHE surveys, among which in particular we use the results from the first Large High Altitude Air Shower Observatory catalog of γ-ray sources. Six candidates are found. They share similar properties of containing a middle-aged, γ-ray–bright pulsar in their positional error circles (the respective pulsars are J0248+6021, J0359+5414, J0622+3749, J0633+0632, J2006+3102, and J2238+5903), being in a rather clean field without any common Galactic VHE-emitting supernova remnants or (bright) pulsar wind nebulae (PWNe), and showing an absence of any γ-ray emissions in 0.1–500 GeV after removing the pulsars’ emissions. Combining these candidates with several reported (candidate) TeV halos, we obtain relationships between their luminosity at 50 TeV (L
50TeV) and the corresponding pulsars’ spin-down energy (

E

̇

), which are

L

50
TeV

∼

E

̇

0.9

and

L

50
TeV

/

E

̇

∼
6.4
×

10

−
4

, respectively. The relationships are nearly identical to previously reported ones. We probe possible connections between the extent/sizes of the VHE sources and the pulsars’ ages, and find a weak older-and-smaller trend. By comparing to the VHE detection results for PWNe, it is clear that the (candidate) TeV halos have hard emissions by either having power-law indices smaller than 2 in 1–25 TeV or by only being detected in 25–100 TeV. In addition, we also consider seven other VHE sources as possible TeV halos based on the results from different studies of them, but they do not fit cleanly with the properties listed above, indicating their potentially complex nature.
CO Observations of Early-mid Stage Major Mergers in the MaNGA Survey
Authors: Yu 余 Qingzheng 清正 , Fang 方 Taotao 陶陶 , Xu 徐 Cong Kevin 聪 , Feng 冯 Shuai 帅 , Feng 冯 Siyi 思轶 , Gao 高 Yu 煜 , Jiang 蒋 Xue-Jian 雪健 , Lisenfeld Ute 
Published: June 2024

Abstract
We present a study of the molecular gas in early-mid stage major mergers, with a sample of 43 major-merger galaxy pairs selected from the Mapping Nearby Galaxies at Apache Point Observatory survey and a control sample of 195 isolated galaxies selected from the xCOLD GASS survey. Adopting kinematic asymmetry as a new effective indicator to describe the merger stage, we aim to study the role of molecular gas in the merger-induced star formation enhancement along the merger sequence of galaxy pairs. We obtain the molecular gas properties from CO observations with the James Clerk Maxwell Telescope, Institut de Radioastronomie Milimetrique 30 m telescope, and the MaNGA-ARO Survey of CO Targets survey. Using these data, we investigate the differences in molecular gas fraction (

f

H

2

), star formation rate (SFR), star formation efficiency (SFE), molecular-to-atomic gas ratio (

M

H

2

/M
H i
), total gas fraction (f
gas), and the SFE of total gas (SFEgas) between the pair and control samples. In the full pair sample, our results suggest the

f

H

2

of paired galaxies is significantly enhanced, while the SFE is comparable to that of isolated galaxies. We detect significantly increased

f

H

2

and

M

H

2

/M
H i
in paired galaxies at the pericenter stage, indicating an accelerated transition from atomic gas to molecular gas due to interactions. Our results indicate that the elevation of

f

H

2

plays a major role in the enhancement of global SFR in paired galaxies at the pericenter stage, while the contribution of enhanced SFE in specific regions requires further explorations through spatially resolved observations of a larger sample spanning a wide range of merger stages.
The R2D2 Deep Neural Network Series Paradigm for Fast Precision Imaging in Radio Astronomy
Authors: Aghabiglou Amir , Chu Chung San , Dabbech Arwa , Wiaux Yves 
Published: June 2024

Abstract
Radio-interferometric imaging entails solving high-resolution high-dynamic-range inverse problems from large data volumes. Recent image reconstruction techniques grounded in optimization theory have demonstrated remarkable capability for imaging precision, well beyond CLEAN’s capability. These range from advanced proximal algorithms propelled by handcrafted regularization operators, such as the SARA family, to hybrid plug-and-play (PnP) algorithms propelled by learned regularization denoisers, such as AIRI. Optimization and PnP structures are however highly iterative, which hinders their ability to handle the extreme data sizes expected from future instruments. To address this scalability challenge, we introduce a novel deep-learning approach, dubbed “Residual-to-Residual DNN series for high-Dynamic-range imaging” or in short R2D2. R2D2's reconstruction is formed as a series of residual images, iteratively estimated as outputs of deep neural networks (DNNs) taking the previous iteration’s image estimate and associated data residual as inputs. It thus takes a hybrid structure between a PnP algorithm and a learned version of the matching pursuit algorithm that underpins CLEAN. We present a comprehensive study of our approach, featuring its multiple incarnations distinguished by their DNN architectures. We provide a detailed description of its training process, targeting a telescope-specific approach. R2D2's capability to deliver high precision is demonstrated in simulation, across a variety of image and observation settings using the Very Large Array. Its reconstruction speed is also demonstrated: with only a few iterations required to clean data residuals at dynamic ranges up to 105, R2D2 opens the door to fast precision imaging. R2D2 codes are available in the BASPLib (https://basp-group.github.io/BASPLib/) library on GitHub.
Application of optic coherence tomography as a screening in prevention and control of diabetic retinopathy
Authors: Kirkova Radina , Tanev Ivan , Dimitrov Tzvetomir , Dimitrova Tanya , Kirkov Vidin 
Published: June 2024

Background. Diabetes mellitus is a leading cause of death, disability, and adult blindness from diabetic retinopathy worldwide. Recent studies have provided a better understanding of the disease process and have opened new doors for prevention and treatment.
The aim of our study is to evaluate the effectiveness of the current screening methods for prevention and control of dia-betic retinopathy and to create a program for optimization.
Material and methods. We included 123 patients with type 1 and type 2 diabetes mellitus. Clinical characteristics of the population were collected from patients’ files. The HbA1c level was measured.
Results. Among examined cohort group – 45% are with diabetes type 1 and 55% with diabetes type 2. In distribution by gender the prevalence is for males. The biggest part of the participants in our study is in the age group 45–66 years old. In 94% of the patients the duration of the disease is between 3–10 years. 22% of the pa-tients are with non-proliferative diabetic retinopathy (NPDR), 45% with proliferative diabetic retinopathy (PDR) and 33% with diabetic macular edema (DME).
Conclusion. Our opinion is that the current ophthalmologic devices, such as fundus cameras and OCT (multimodal imaging), should be incorporated in the process of screening for diabetic retinopathy due to the detailed information they provide and the short time to perform the procedure.
Aux marges du « développement », les espaces discrets du contrôle migratoire. Quand le « panafricanisme entrepreneurial » fait frontière en Tunisie
Authors: Cassarini Camille 
Published: June 2024

Cet article interroge la position des acteurs entrepreneuriaux estudiantins dans la mise en œuvre du contrôle migratoire en Tunisie. Au croisement des mondes de la migration et du développement, les « étudiants africains » ont été, depuis 2015 et l’arrivée de nombreux fonds européens dédiés à la gestion des migrations, une cible privilégiée des acteurs du gouvernement international des migrations. Souvent chargés de « sensibiliser » les personnes considérées comme « migrantes » aux risques de la migration et aux opportunités du modèle entrepreneurial en Afrique, ces acteurs développent des modèles de réussite fondés sur l’accès à la mobilité et sur la promotion de celle-ci au sein du continent africain. Refusant une lecture strictement opportuniste de leurs pratiques, cet article cherche à saisir en quoi l’engagement de ces étudiants dans la mise en ordre des mobilités se branche sur un imaginaire politique panafricaniste.
Léonard de Vinci, l’expérience de l’art
Authors: Menu Michel 
Published: June 2024

Pour Léonard, l’expérience est « mère commune des arts et des sciences ». En expérimentaliste, il développe son art, sa technique picturale, en expérimentaliste, il perçoit le réel, il cherche à comprendre la nature, et, pour expérimenter son rapport au monde, il a recours au miroir qui permet de distinguer l’image de la réalité. Le miroir est aussi un moyen d’entrer dans l’œuvre de l’artiste.Depuis la conférence tenue à la National Gallery de Londres en 2015 consacrée à la Pratique technique de Léonard de Vinci, de nouvelles expériences furent réalisées à l’aide d’outils innovants, récemment développés, les scanners de fluorescence X et d’imagerie hyperspectrale. En marge de l’exposition au Louvre célébrant le 500e anniversaire de la mort de l’artiste à Amboise, la journée d’étude du 25 octobre 2019 rend compte des nouvelles découvertes sur l’art et la science de Léonard.
Sur quelques essais de restitution expérimentale des médaillons de draperies léonardiennes
Authors: Frank Louis , Leratti Leticia 
Published: June 2024

Les auteurs présentent ici le cheminement intellectuel qui les a conduits à restituer le modèle en « médaille », c’est-à-dire en haut relief plutôt qu’en ronde bosse intégrale, que Léonard de Vinci conçut très probablement lorsqu’il peignit en grisaille la Draperie pour une figure assise dite Draperie Saint-Morys, conservée au département des Arts graphiques du musée du Louvre (inv. 2255).