bluuebunny/crossref_metadata_2025 huggingface dataset:
The correlation between gastric diseases and dental caries
Authors:   Department of Oral Diagnosis, University of Basrah, College of Dentistry, Basrah, Iraq, Al-Essa Hussein Sh. , Fadil Adil G ,   Department of Pediatric Dentistry and Prevention, University of Basrah University, College of Dentistry, Basrah, Iraq, Kadhim Assad Mohammed ,   Department of Oral and Maxillofacial Surgery, University of Basrah, College of Dentistry, Basrah, Iraq
Published: April 2024

Background. The oral cavity is a mirror that reflects and unravels many of the human body's internal secrets. Some of these manifestations are disease-specific and help raise a high degree of suspicion for the alert clinician and dentist. So, the goal of this case-control study is to determine whether there is a link between gastric diseases and dental caries. Methodology. Examinations were performed on (250) patients, all of them suffering from dental caries in varies degree: We relied on statistical information that we gathered through a questionnaire form, which included the results of numerous different clinical outcomes for both (150) healthy people and those 100 with gastric disorders from a variety of genders, ages, residency, and we calculate DMFT index for both groups. Results. There was a statistically significant differences in the mean DMFT between health and gastric disease participants. Conclusions. A noteworthy correlation exists between gastric disorders and dental caries, as well as oral manifestation lesions and associated consequences like erosion.
Occupational stressors and associated factors among dentists in Erbil City, Kurdistan Region-Iraq
Authors:   Dental public health center at Kurdistan Higher Council of Medical Specialties in Erbil City, Kurdistan Region, Iraq, Hamonari Nasreen Hamarash
Published: April 2024

Background. The health and well-being of dentists are essential components of a successful dental practice. Many studies showing high levels of stress, burnout, and psychological distress reported by dental professionals. Objective. To assess the main occupational stressors among dentists practicing in Erbil city and to identify the associated factors that lead to or aggravate these stressors experienced in the work environment. Subjects, materials and methods. This was a cross-sectional study conducted from August to October 2023. Data were collected from private and two government dental teaching institutions, along with accessible dental clinical practices. A total of 220 dentists were recruited. A modified version of the Occupational Stress Indicator questionnaire was used to assess the stressors. The study was approved by the Research Ethics Committee of the Kurdistan Board for Medical Specialties. The questionnaire consisted of two sections, the first gathering demographic and professional data of the participants, while the second section contained 33 items assessing the causes of stress. Participants rated the frequency of stressors using a scale of “never”, “seldom”, “sometimes”, “often”, “very often”, and “always”. Results. The response rate was 199/220 (90.5%). 64.3% of participants were younger than 38 years. Males contributed for 57.3%. The mean total stress score was 90 ± 17.6. Higher stress score was significantly associated with the presence of health problems, (p<0.05). A lower mean stress score was reported among dentists who were practicing their job only in private clinics, (p<0.05). No other factors showed a significant correlation with stress scores. Conclusion. Dentistry is a stressful profession and there are significant stressors that dental professionals face in their daily work, which can have implications for their overall well-being and the quality of patient care. There is a significant association between stress levels and the presence of health problems, as well as the place of employment.
Teledentistry in Palestine: challenges and prospects
Authors:   Department of Conservative Dentistry, Faculty of Dentistry, Arab American University, Jenin, Palestine, Arandi Naji Ziad
Published: April 2024

In the rural areas of Palestine, where access to dental services is limited, teledentistry emerges as a promising solution to address oral healthcare challenges, especially in remote or underserved areas. However, the successful implementation of teledentistry depends on addressing various factors crucial for overcoming barriers and realizing its full potential. This paper aims to highlight these challenges and underscore the importance of addressing them to facilitate the successful implementation of teledentistry in Palestine.
Diabetic Retinopathy Stage Detection Using CNN and Inception V3
Authors: Jayasri T. , Prudhvi Raj Yakkala , Harshitha Maartha , Raghavendra Rao Pallapati , Krshina Akhil Devireddy Sai
Published: April 2024

The project explores the deployment of Convolutional Neural Networks (CNN) and the Inception V3 model for the automated detection and classification of diabetic retinopathy stages using fundus images. Recognizing diabetic retinopathy as a leading cause of blindness among the working-age population globally, this research aims to streamline the diagnostic process, traditionally reliant on the manual examination by ophthalmologists. Through the utilization of the DRIVE and STARE datasets, the project benchmarks the performance of CNN and Inception V3 models in accurately categorizing the severity of diabetic retinopathy into five distinct stages. The comparison between these models is grounded on parameters such as accuracy, loss, and predicted value, with findings indicating Inception V3's superiority in both performance metrics and diagnostic precision. This advancement could significantly contribute to early and more accessible detection of diabetic retinopathy, thereby mitigating progression towards blindness. Furthermore, the project underscores the potential of deep learning algorithms in enhancing diagnostic methodologies for retinal diseases, paving the way for future explorations in the field of medical imaging and artificial intelligence.
Dense Wavelength Division Multiplexing (DWDM) in IT Networks: A Leap Beyond Synchronous Digital Hierarchy (SDH)
Authors: Bu Haymid Abdullah
Published: April 2024

The evolution of telecommunications has seen significant milestones, notably the shift from Synchronous Digital Hierarchy (SDH) to Dense Wavelength Division Multiplexing (DWDM). This transition marks a pivotal advancement in the performance of Information Technology (IT) networks, offering unparalleled improvements in bandwidth, scalability, and efficiency. DWDM technology enables the simultaneous transmission of multiple data streams across a single optical fiber by using different wavelengths of light, significantly enhancing data throughput and network capacity. This article delves into the technical foundations of DWDM, compares its performance enhancements over SDH systems, and explores its impact on modern IT network infrastructure.
The Influence of Menu Variations, Location, and Service Quality on Consumer Purchasing Decisions at Terrace Brasserie in Canggu, Badung Regency
Authors: SANJAYA Ni Luh Putu Mutiara Utami , DHARMANEGARA Ida Bagus Agung , SARIANI Ni Ketut
Published: April 2024

Purpose:This research aims to test and analyze the influence of menu variations, location and service quality on purchasing decisions.Methodology:This research was conducted at Terrace Brasserie Canggu with a significant research sample 100 respondents were taken using the Slovin formula. All data obtained from the distribution of the questionnaires are suitable for use. The data were then analyzed using multiple linear regression and hypothesis testing (t-test and f-test).Findings:The results of this research show that (1) Menu variations, location and service quality have a positive and significant effect on purchasing decisions at Terrace Brasserie Canggu, (2) Menu variations have a positive and significant effect on purchasing decisions at Terrace Brasserie Canggu. It means that the more menu variations there are, the more purchasing decisions at Terrace Brasserie Canggu will increase. (3) Location positively and significantly affects purchasing decisions at Terrace Brasserie Canggu. It means that the more strategically the location is, the more purchasing decisions at Terrace Brasserie Canggu will increase. (4) Service quality positively and significantly affects purchasing decisions at Terrace Brasserie Canggu.Implication:This means that the more service quality increases, the more purchasing decisions at Terrace Brasserie Canggu will increase.
The Influence of Corporate Social Responsibility, Profitability, Liquidity, and Leverage on Tax Aggressivity
Authors: ARTHA Ngurah Adi Kusuma , RINI Gusti Ayu Intan Saputra , DEWI I Gst. Ayu Ratih Permata
Published: April 2024

Purpose:The phenomenon that occurred in 2019, PT. Adaro Energy Tbk. Do something avoidance related to payment tax by implementing transfer pricing through the branch. The Company is located in Singapore and is called Coaltrade Services International. From 2009-2017, information via child company pays tax amounting to 125 million USD or Rp. 1.75 trillion ( exchange rate Rp. 14,000) or more small from it should be charged in Indonesia. Study This aims To analyze the influence of corporate social responsibility, Profitability, liquidity and Leverage on aggressiveness tax on IDX30 companies listed on the Indonesian Stock Exchange in 2020-2022.Methodology:This study is based on a deep data study, using secondary data from IDX30 companies listed on the Indonesian Stock Exchange from 2020 to 2022. 13 companies were included in the study and selected through a purposive sampling method. The data was analyzed using multiple linear regression, a statistical technique used to analyze the relationship between multiple independent variables and a dependent variable.Findings:Research results show that corporate social responsibility positively and significantly impacts aggressiveness tax. Implication:On the other hand, Profitability, liquidity, and Leverage are not influential factors in aggressive tax.
CAUSALIDAD ENTRE LOS PRECIOS DEL PETROLEO WEST TEXAS INTERMEDIATE (WTI) Y LAS ACTIVIDADES ECONOMICAS DESARROLLADAS EN BOLIVIA, PERIODO 2011 - 2020.
Authors: Rojas Padilla Carlos Alberto
Published: April 2024

Establecer la relación causal entre la variable precios internacionales del petróleo, considerando los precios del crudo producido en Texas y el sur de Oklahoma (WTI) y la variable actividad económica en Bolivia, fundamentada en la información trimestral presentada en las estadí­sticas económicas en el apartado de cuentas nacionales del Instituto Nacional de Estadí­stica, representa el alcance de la investigación, a partir de una conjetura previa "Existe causalidad entre los precios del petróleo West Texas Intermediate (WTI) y las actividades económicas desarrolladas en Bolivia, periodo 2011 - 2020" el diseño metodológico eminentemente cuantitativo, con la información histórica resumida en 38 datos trimestrales presentados en series de tiempo, permitió el tratamiento estadí­stico de los datos. El abordaje estadí­stico de los datos, se desarrolló en base al programa Excel de Windows 2013, y el programa EVIEWS, en primera instancia la determinación de la correlación simple y el grado de determinación entre las variables en general, en base a los resultados, permite afirmar que la relación de la variable WTI, con el PIB y los principales sectores de la economí­a boliviana, es inexistente, no existe ajuste entre las variables, las fluctuaciones en los precios del petróleo, no explican los cambios en las variables económicas bolivianas; sin embargo se pudo determinar que en el caso del sector servicios financieros y gasto de la administración pública presentan una relación mí­nima con la variable WTI, además se estableció que esta relación mí­nima es indirecta, mientras que el nivel de ajuste oscila entre el 22% al 29%. El test de causalidad de Granger, utilizando el análisis VAR, considerando 4 rezagos, permitió reforzar las conclusiones anteriores en el sentido de que no existe causalidad de Granger entre las variables analizadas, la variable X, no causa a la variable Y en el sentido de Granger, de existir algún grado de relación entre las variables, fue posible establecer que esta relación seria espuria, ya que, no existe cointegracií²n es decir que no existe sincroní­a entre los ascensos y descensos de las variables. PALABRAS CLAVE Correlación, Determinación, Causalidad, Cointegracií²n, Granger
SATISFACCIÓN DE LOS ESTUDIANTES EN EL POSGRADO: ELEMENTOS DE INFLUENCIA Y POLíTICAS PARA SU MEJORAMIENTO EN UNA UNIVERSIDAD EN ECUADOR
Authors: Raza-Carrillo Diego F.
Published: April 2024

A partir de una revisión bibliográfica sobre satisfacción y calidad en la universidad se hace una crí­tica al enfoque empresarial de estos conceptos, aceptando que pese a ello es importante comprender la valoración que hace el estudiante a su experiencia universitaria. A continuación se resume el sistema de evaluación de la universidad en la que se realizó el estudio y sus componentes, y a partir del procesamiento de sus más de 250 mil registros en el departamento y perí­odo seleccionados, se determina que los elementos de mayor incidencia en la valoración general que hace el estudiante corresponden a los servicios no académicos concesionados (restaurante, cafeterí­a, impresión y fotocopias), seguido de los servicios no académicos gestionados directamente por la universidad (internet dentro del campus y acceso electrónico al parqueadero). En los aspectos académicos los elementos que inciden en una menor valoración del estudiante fueron el aporte de la asignatura a la formación profesional y el nivel académico de la asignatura.
First Detection of Outflowing Gas in the Outskirts of the Broad-line Region in 1H 0707−495*
Authors: Rodríguez-Ardila Alberto , Fonseca-Faria Marcos Antonio , Dias dos Santos Denimara , Panda Swayamtrupta , Marinello Murilo
Published: April 2024

We use near-infrared spectroscopy covering simultaneously the zJHK bands to look for outflowing gas from the nuclear environment of 1H 0707−495 taking advantage that this region is dominated by low-ionization broad-line region lines, most of them isolated. We detect broad components in H i, Fe ii, and O i, at rest to the systemic velocity, displaying FWHM values of ∼500 km s−1, consistent with its classification as a narrow-line Seyfert 1 active galactic nucleus. Moreover, most lines display a conspicuous blue-asymmetric profile, modeled using a blueshifted component, whose velocity shift reaches up to ∼826 km s−1. This last feature can be interpreted in terms of outflowing gas already observed in X-ray and UV lines in 1H 0707−495 but not detected before in the low-ionization lines. We discuss the relevance of our findings within the framework of the wind scenario already proposed for this source and suggest that the wind extends well into the narrow-line region owing to the observation of a blueshifted component in the forbidden line of [S iii] λ9531.
GN-z11 in Context: Possible Signatures of Globular Cluster Precursors at Redshift 10
Authors: Senchyna Peter , Plat Adele , Stark Daniel P. , Rudie Gwen C. , Berg Danielle , Charlot Stéphane , James Bethan L. , Mingozzi Matilde
Published: April 2024

The first JWST spectroscopy of the luminous galaxy GN-z11 simultaneously established its redshift at z = 10.6 and revealed a rest-ultraviolet spectrum dominated by signatures of highly ionized nitrogen, which has so far defied clear interpretation. We present a reappraisal of this spectrum in the context of both detailed nebular modeling and nearby metal-poor reference galaxies. The N iv] emission enables the first nebular density measurement in an apparently predominantly star-forming galaxy at z > 10, revealing evidence for extremely high densities n

e
≳ 105 cm−3. With a suite of photoionization models, we establish that regardless of the ionization mechanism and accounting for depletion and this density enhancement, gas substantially enriched in nitrogen ([N/O] = +0.52 assuming the nebular emission is dominated by star formation) is required to reproduce the observed lines. We compare the GN-z11 spectrum to local UV databases and highlight a unique nearby galaxy, Mrk 996, where a high concentration of Wolf–Rayet stars and their CNO-processed ejecta produce a UV spectrum remarkably similar in some respects to that of GN-z11 and the Sunburst Arc. Collating this evidence in the context of Galactic stellar abundances, we suggest that the peculiar nitrogenic features prominent in GN-z11 may be a unique signature of intense and densely clustered star formation in the evolutionary chain of the present-day globular clusters, consistent with in situ early enrichment with nuclear-processed stellar ejecta on a massive scale. Combined with insight from local galaxies, these and future JWST data open a powerful new window into the physical conditions of star formation and chemical enrichment at the highest redshifts.
Multiple Beads on a String: Dark-matter-deficient Galaxy Formation in a Mini-Bullet Satellite–Satellite Galaxy Collision
Authors: Lee Joohyun , Shin Eun-jin , Kim Ji-hoon , Shapiro Paul R. , Chung Eunwoo
Published: April 2024

Dark-matter-deficient galaxies (DMDGs) discovered in the survey of ultra-diffuse galaxies (UDGs), in apparent conflict with standard cold dark matter, may be produced by high-velocity galaxy–galaxy collisions, the so-called Mini-Bullet scenario. Recent observations of an aligned trail of 7–11 UDGs near NGC 1052, including DMDGs DF2 and DF4, suggesting a common formation event, ∼8.9 ± 1.5 Gyr ago, provide a test.Hydro/N-body simulations, supplemented by galaxy orbit integrations, demonstrate that satellite–satellite collisions outside the host-galaxy virial radius can reproduce the observed UDGs in the NGC 1052 group. A trail of ∼10 DMDGs is shown to form, including 2 massive ones that replicate the observed motions of DF2 and DF4. The linear relation,
v
= A

x
+
v

0, conjectured previously to relate positions (
x
) and velocities (
v
) of the aligned DMDGs as a signature of the collision event, is approximately obeyed, but individual DMDGs can deviate significantly from it. The progenitors whose collision spawned the trail of DMDGs survive the collision without themselves becoming DMDGs. We predict that one progenitor is located at the end of the trail, which can be tested by observing the difference between its stars, formed pre-collision, from those of the DMDGs, formed post-collision. By contrast, stellar ages and metallicities of the DMDGs are nearly identical. We further offer a hint that the tidal field of host NGC 1052 may contribute to making DMDGs diffuse. ΛCDM simulation in a 100 cMpc box finds our required initial conditions ∼10 times at z < 3. These results indicate current observations are consistent with the Mini-Bullet scenario.
Evolution of the Interplanetary Turbulence and the Associated Turbulence Anisotropy in the Outer Heliosphere: VOYAGER 2 Observations
Authors: Zhu Xingyu , He Jiansen , Zank Gary P. , Verscharen Daniel , Zhao Ling-Ling , Duan Die , Lin Rong
Published: April 2024

We study the radial evolution of the inertial-range solar wind plasma turbulence and its anisotropy in the outer heliosphere. We use magnetic field (
B
) measurements from the Voyager 2 spacecraft for heliocentric distances R from 1 to 33 au. We find that the perpendicular and trace power spectral densities (PSDs) of the magnetic field (

E

B

⊥

and

E

B

Tr

) still follow a Kolmogorov-like spectrum until 33 au. The parallel magnetic field PSD,

E

B

∥

, transits from a power-law index of −2 to −5/3 as the distance crosses R ∼ 10 au. The PSD at frequencies 0.01 Hz < f < 0.2 Hz flattens at R > 20 au, gradually approaching an f
−1 spectrum, probably due to instrument noise. At 0.002 Hz < f < 0.1 Hz, quasi-parallel propagation dominates at 1 au < R < 7 au, with quasi-perpendicular propagation gradually emerging at R > 5 au. For R > 7 au, oblique propagation becomes the primary mode of propagation. At smaller frequencies of f < 0.01 Hz,

E

B

⊥

increases with propagation angle at 1 au < R < 5 au, and in contrast decreases with propagation angle at R > 5 au due to the enhanced power level at propagation angles smaller than 20°. Such enhancement may derive from the injection of wave energy from the pickup ion source into the background turbulent cascade, and the injected wave energy is transferred across scales without leaving local enhancements in

E

B

⊥

or

E

B

Tr

.
The Physical Properties of Low-redshift FeLoBAL Quasars. IV. Optical–Near-IR Spectral Energy Distributions and Near-IR Variability Properties
Authors: Leighly Karen M. , Choi 최 Hyunseop 현섭 , Eracleous Michael , Terndrup Donald M. , Gallagher Sarah C. , Richards Gordon T.
Published: April 2024

We present the optical–near-infrared spectral energy distributions (SED) and near-infrared variability properties of 30 low-redshift iron low-ionization Broad Absorption Line quasars (FeLoBALQs) and matched samples of LoBALQs and unabsorbed quasars. Significant correlations between the SED properties and accretion rate indicators found among the unabsorbed comparison sample objects suggest an intrinsic origin for SED differences. A range of reddening likely mutes these correlations among the FeLoBAL quasars. The rest-frame optical-band reddening is correlated with the location of the outflow, suggesting a link between the outflows and the presence of dust. We analyzed the WISE variability and provide a correction for photometry uncertainties in an appendix. We found an anticorrelation between the variability amplitude and inferred continuum emission region size, and we suggest that as the origin of the anticorrelation between variability amplitude and luminosity typically observed in quasars. We found that the LoBALQ Optical Emission-line and other parameters are more similar to those of the unabsorbed continuum sample objects than the FeLoBALQs. Thus, FeLoBAL quasars are a special population of objects. We interpret the results using an accretion-rate scenario for FeLoBAL quasars. The high-accretion-rate FeLoBAL quasars are radiating powerfully enough to drive a thick, high-velocity outflow. Quasars with intermediate accretion rates may have an outflow, but it is not sufficiently thick to include Fe ii absorption. Low-accretion-rate FeLoBAL outflows originate in absorption in a failing torus, no longer optically thick enough to reprocess radiation into the near-IR.
AB Dor: Coronal Imaging and Activity Cycles
Authors: Singh Gurpreet , Pandey J. C.
Published: April 2024

Using long-term X-ray observations, we present short-term and long-term X-ray variability analysis of the ultrafast rotating active star AB Dor. Flaring events are common in X-ray observations of AB Dor and occupy a substantial portion of the total observation time, averaging at around 57% ± 23%. The flare-free X-ray light curves show rotational modulation, indicating the presence of highly active regions in the star's corona. We have developed a light-curve inversion code to image the corona of active fast rotating stars. The results of coronal imaging reveal the presence of two active regions of different brightness that are separated by ∼180° in longitude. These active regions are also found to migrate along the longitude and also show variation in their brightness. Our analysis of long-term X-ray data spanning from 1979 to 2022 shows multiple periodicities. The existence of a ∼19.2 yr cycle and its first harmonic indicates the presence of a solar-like, long-term pattern. In comparison, the periodicities of ∼3.6 and ∼5.4 yr are possibly due to the presence of a flip-flop cycle in the X-rays, which is also supported by findings for similar periods from the optical data in earlier studies. Further confirmation of the existence of the X-ray flip-flop cycle requires long-term observations at regular intervals in the quiescent state.
The Relationships among Solar Flare Impulsiveness, Energy Release, and Ribbon Development
Authors: Tamburri Cole A. , Kazachenko Maria D. , Kowalski Adam F.
Published: April 2024

We develop the impulsiveness index, a new classification system for solar flares using the Solar Dynamics Observatory/Extreme Ultraviolet Experiment 304 Å Sun-as-a-star light curves. Impulsiveness classifies events based on the duration and intensity of the initial high-energy deposition of energy into the chromosphere. In stellar flare U-band light curves, Kowalski et al. found that impulsiveness is related to quantities such as a proxy for the Balmer jump ratio. However, the lack of direct spatial resolution in stellar flares limits our ability to explain this phenomenon. We calculate impulsiveness for 1368 solar flares between 2010 April and 2014 May. We divide events into categories of low, mid, and high impulsiveness. We find, in a sample of 480 flares, that events with high maximum reconnection rate tend to also have high impulsiveness. For six case studies, we compare impulsiveness to magnetic shear, ribbon evolution, and energy release. We find that the end of the 304 Å light-curve rise phase in these case studies corresponds to the cessation of polarity inversion line (PIL)-parallel ribbon motion, while PIL-perpendicular motion persists afterward in most cases. The measured guide-field ratio for low- and mid-impulsiveness case-study flares decreases about an order of magnitude during the impulsive flare phase. Finally, we find that, in four of the six case studies, flares with higher, more persistent shear tend to have low impulsiveness. Our study suggests that impulsiveness may be related to other properties of the impulsive phase, though more work is needed to verify this relationship and apply our findings to stellar flare physics.
Mid-infrared Properties of Narrow-line Seyfert 1 Galaxies Detected by LoTSS DR2
Authors: Fan Xu-Liang
Published: April 2024

Narrow-line Seyfert 1 galaxies (NLS1s), a subclass of active galactic nuclei (AGNs) in an early stage of the accretion process, are also found to host relativistic jets. However, currently known jetted NLS1s are rare. The majority of NLS1s are undetected at the radio band. The radio detection rate of NLS1s increases with the LOFAR Two-metre Sky Survey (LoTSS), which provides a good opportunity for finding more jetted NLS1s. The better sensitivity raises the question whether the radio emission of NLS1s with a low radio luminosity originates from the jet activity. In order to clarify the origin of the radio emission for NLS1s and search for more jetted NLS1s, we explore the mid-infrared properties of LoTSS-detected NLS1s by comparing them with known jetted AGNs and star-forming galaxies (SFGs), which are located above and on the well-studied radio/far-infrared correlation, respectively. The majority of NLS1s show mid-infrared (MIR) excess compared with SFGs. Their radio emission shows a significant correlation with the MIR emission. In the MIR color–color diagram, NLS1s overlap flat spectrum radio quasars, but they are well separated from SFGs and optically selected radio galaxies. The flux ratio of the radio and MIR emission of these NLS1s is also similar to that of a radio-quiet quasar with a weak jet. These results imply substantial contributions from the AGN activities for both the radio and MIR emission of NLS1s. A small fraction of NLS1s with relatively higher radio luminosities are located in a similar region as blazars in the radio-MIR diagram, which suggests that the radio emission of these NLS1s is dominated by the jet. We obtain a sample of jetted NLS1 candidates through their radio excess in the radio-MIR diagram.
How Does the Structure of Rarefaction Regions Develop?
Authors: Ďurovcová Tereza , Šafránková Jana , Němeček Zdeněk
Published: April 2024

A rarefaction region (RR) occurs at the trailing edge of the fast solar wind stream. It comes from an area of small longitudinal extent on the solar surface and exhibits a fine and complex structure. In our study, we did a superposed epoch analysis of the proton and α parameters across the RR and observed their gradual evolution. We did not find any clear boundary between the fast and slow solar winds inside the RR because a majority of our observations show that most of the RR plasma corresponds to the fast solar wind; only the α–proton drift velocity decreases from the beginning of the RR. We investigate different ways of its reduction in interplanetary space and show that this feature is likely associated with the mirroring of the multicomponent solar wind. Nevertheless, considering the observed solar wind characteristics and taking into account the mutual relations between the proton and α parameters, we define the composition boundary where the α relative abundance and α–proton temperature ratio change abruptly from the values typical for the fast wind toward slow wind values. This boundary is the most probable candidate for the stream interface. Based on these findings, we speculate that the RR formation starts already near the Sun and formulate two possible scenarios.
Gas and Star Formation in Satellites of Milky Way Analogs
Authors: Jones Michael G. , Sand David J. , Karunakaran Ananthan , Spekkens Kristine , Oman Kyle A. , Bennet Paul , Besla Gurtina , Crnojević Denija , Cuillandre Jean-Charles , Fielder Catherine E. , Gwyn Stephen , Mutlu-Pakdil Burçin
Published: April 2024

We have imaged the entirety of eight (plus one partial) Milky Way (MW)–like satellite systems, a total of 42 (45) satellites, from the Satellites Around Galactic Analogs II catalog in both Hα and H i with the Canada–France–Hawaii Telescope and the Jansky Very Large Array. In these eight systems we have identified four cases where a satellite appears to be currently undergoing ram pressure stripping (RPS) as its H i gas collides with the circumgalactic medium (CGM) of its host. We also see a clear suppression of gas fraction (M
HI/M
*) with decreasing (projected) satellite–host separation—to our knowledge, the first time this has been observed in a sample of MW-like systems. Comparisons to the Auriga, A Project Of Simulating The Local Environment, and TNG50 cosmological zoom-in simulations show consistent global behavior, but they systematically underpredict gas fractions across all satellites by roughly 0.5 dex. Using a simplistic RPS model, we estimate the average peak CGM density that satellites in these systems have encountered to be

log

ρ

cgm

/

g

cm

−
3

≈
−
27.3

. Furthermore, we see tentative evidence that these satellites are following a specific star formation rate to gas fraction relation that is distinct from field galaxies. Finally, we detect one new gas-rich satellite in the UGC 903 system with an optical size and surface brightness meeting the standard criteria to be considered an ultra-diffuse galaxy.
METAL-Z: Measuring Dust Depletion in Low-metallicity Dwarf Galaxies
Authors: Hamanowicz Aleksandra , Tchernyshyov Kirill , Roman-Duval Julia , Jenkins Edward B. , Rafelski Marc , Gordon Karl D. , Zheng Yong , Garcia Miriam , Werk Jessica
Published: April 2024

The cycling of metals between interstellar gas and dust is a critical aspect of the baryon cycle of galaxies, yet our understanding of this process is limited. This study focuses on understanding dust depletion effects in the low-metallicity regime (<20% Z
⊙) typical of cosmic noon. Using medium-resolution UV spectroscopy from the Cosmic Origins Spectrograph on board the Hubble Space Telescope, gas-phase abundances and depletions of iron and sulfur were derived toward 18 sight lines in local dwarf galaxies IC 1613 and Sextans A. The results show that the depletion of Fe and S is consistent with that found in the Milky Way (MW), LMC, and SMC. The depletion level of Fe increases with gas column density, indicating dust growth in the interstellar medium. The level of Fe depletion decreases with decreasing metallicity, resulting in the fraction of iron in gas ranging from 3% in the MW to 9% in IC 1613 and ∼19% in Sextans A. The dust-to-gas and dust-to-metal ratios (D/G, D/M) for these dwarf galaxies were estimated based on the MW relations between the depletion of Fe and other elements. The study finds that D/G decreases only slightly sublinearly with metallicity, with D/M decreasing from 0.41 ± 0.05 in the MW to 0.11 ± 0.11 at 0.10 Z
⊙ (at log N(H) = 21 cm−2). The trend of D/G versus metallicity using depletion in local systems is similar to that inferred in Damped Lyα systems from abundance ratios but lies higher than the trend inferred from far-IR measurements in nearby galaxies.
Identifying Coronal Sources of L1 Solar Wind Disturbances Using the Fisk Heliospheric Magnetic Field and Potential Field Extrapolations during Three Solar Minima
Authors: Steyn P. J. , Johnson D. , Botha G. J. J. , Régnier S.
Published: April 2024

The solar minima between solar cycles 22–23, 23–24, and 24–25 are the best observed minima on record. In situ solar wind and interplanetary magnetic field measurements by the Wind and ACE spacecraft at L1 with 1 hr cadence are explored using wavelet analyses for the most quiescent year during each minimum. Times of local peaks in periodicities are identified in the solar wind velocity, magnetic field components, and proton number densities. The measured radial velocities at these times are used to trace magnetic field lines to the photosphere using two models. The first is the Fisk heliospheric magnetic field that traces field lines from L1 to the photosphere. They connect exclusively to solar poles and in 88% of instances to locations of polar coronal holes (PCHs). The second model uses the Parker spiral to trace from L1 to the solar source surface and potential-field extrapolations from the source surface to the photosphere. These field lines terminate at equatorial and midlatitude coordinates, of which some are located close to coronal holes (CHs). This study connects for the first time CH signatures in the ecliptic plane at L1 with PCHs using the Fisk field. It shows how sources from both the solar equator and poles influence the solar wind at L1 and how the two models complement each other to identify these sources.
Limits on the OH Molecule in the Smith High-velocity Cloud
Authors: Minter Anthony H. , Lockman Felix J. , Balashev S. A. , Ford H. Alyson
Published: April 2024

We have used the Green Bank Telescope to search for the OH molecule at several locations in the Smith Cloud, one of the most prominent of the high-velocity clouds surrounding the Milky Way. Five positions with high H i column density were selected as targets for individual pointings, along with a square degree around a molecular cloud detected with the Planck telescope near the tip of the Smith Cloud. Gas in the Galactic disk with similar values of N
HI has detectable OH emission. Although we found OH at velocities consistent with the foreground Aquila molecular cloud, nothing was found at the velocity of the Smith Cloud to an rms level of 0.7 mK (T

b
) in a 1 km s−1 channel. The three positions that give the strictest limits on OH are analyzed in detail. Their combined data imply a 5σ limit on N(H2)/N
HI ≤ 0.03, scaled by a factor dependent on the OH excitation temperature and background continuum T
ex/(T
ex − T
bg). There is no evidence for far-infrared emission from dust within the Smith Cloud. These results are consistent with expectations for a low-metallicity diffuse cloud exposed to the radiation field of the Galactic halo, rather than a product of a galactic fountain.
Characterization of Turbulent Fluctuations in the Sub-Alfvénic Solar Wind
Authors: Zank G. P. , Zhao L.-L. , Adhikari L. , Telloni D. , Baruwal Prashant , Baruwal Prashrit , Zhu Xingyu , Nakanotani M. , Pitňa A. , Kasper J. C. , Bale S. D.
Published: April 2024

Parker Solar Probe (PSP) observed sub-Alfvénic solar wind intervals during encounters 8–14, and low-frequency magnetohydrodynamic (MHD) turbulence in these regions may differ from that in super-Alfvénic wind. We apply a new mode decomposition analysis to the sub-Alfvénic flow observed by PSP on 2021 April 28, identifying and characterizing entropy, magnetic islands, forward and backward Alfvén waves, including weakly/nonpropagating Alfvén vortices, forward and backward fast and slow magnetosonic (MS) modes. Density fluctuations are primarily and almost equally entropy- and backward-propagating slow MS modes. The mode decomposition provides phase information (frequency and wavenumber k) for each mode. Entropy density fluctuations have a wavenumber anisotropy of k
∥ ≫ k
⊥, whereas slow-mode density fluctuations have k
⊥ > k
∥. Magnetic field fluctuations are primarily magnetic island modes (δ
B

i
) with an O(1) smaller contribution from unidirectionally propagating Alfvén waves (δ
B
A+) giving a variance anisotropy of

〈

δ

B

i

2

〉

/

〈

δ

B

A

2

〉
=
4.1

. Incompressible magnetic fluctuations dominate compressible contributions from fast and slow MS modes. The magnetic island spectrum is Kolmogorov-like

k

⊥

−
1.6

in perpendicular wavenumber, and the unidirectional Alfvén wave spectra are

k

∥

−
1.6

and

k

⊥

−
1.5

. Fast MS modes propagate at essentially the Alfvén speed with anticorrelated transverse velocity and magnetic field fluctuations and are almost exclusively magnetic due to β

p
≪ 1. Transverse velocity fluctuations are the dominant velocity component in fast MS modes, and longitudinal fluctuations dominate in slow modes. Mode decomposition is an effective tool in identifying the basic building blocks of MHD turbulence and provides detailed phase information about each of the modes.
Halo Asymmetry in the Modeling of Galaxy Clustering
Authors: Durkalec Anna , Pollo Agnieszka , Abbas Ummi
Published: April 2024

Conventional studies of galaxy clustering within the framework of halo models typically assume that the density profile of all dark matter halos can be approximated by the Navarro–Frenk–White (NFW) spherically symmetric profile. However, both modern N-body simulations and observational data suggest that most halos are either oblate or prolate, and almost never spherical. In this paper we present a modified model of the galaxy correlation function. In addition to the five “classical” halo occupation distribution (HOD) parameters proposed by Zheng et al., it includes an additional free parameter ϕ in the modified NFW density profile describing the asymmetry of the host dark matter halo. Using a subhalo abundance matching model, we populate galaxies within BolshoiP N-body simulations. We compute the projected two-point correlation function w

p
(r

p
) for six stellar-mass volume-limited galaxy samples. We fit our model to the results and then compare the best-fit asymmetry parameter ϕ (and other halo parameters) to the asymmetry of dark matter halos measured directly from the simulations and find that they agree within 1σ. We then fit our model to the w

p
(r

p
) results from Zehavi et al. and compare halo parameters. We show that our model accurately retrieves the halo asymmetry and other halo parameters. Additionally, we find 2%–6% differences between the halo masses (

log

M

min

and logM
1) estimated by our model and those estimated by “classical” HOD models. The model proposed in this paper can serve as an alternative to multiparameter HOD models, since it can be used for relatively small samples of galaxies.
Stellar Occultations in the Era of Data Mining and Modern Regression Models: Using Gaussian Processes to Analyze Light Curves and Improve Predictions
Authors: Knieling Bastian , Schindler Karsten , Sickafoose Amanda A. , Person Michael J. , Levine Stephen E. , Krabbe Alfred
Published: April 2024

Gaussian process (GP) regression is a nonparametric Bayesian approach that has been used successfully in various astronomical domains, especially in time-domain astronomy. The most common applications are the smoothing of data for interpolation and the detection of periodicities. The ability to create unbiased data-driven models without a predefined physical model can be a major advantage over conventional regression methods. Prior knowledge can be included by setting boundary conditions or constraining hyperparameter values, while unknown hyperparameters are optimized during the conditioning of the model. We have adapted and transformed previous approaches of GP regression and introduce three new applications for this regression method, especially in the context of stellar occultations: the modeling of occultation light curves, the correction of public JPL ephemerides of minor planets based on publicly available image data of the Zwicky Transient Facility, and the detection of natural satellites. We used data from observations of stellar occultations to validate the models and achieved promising results in all cases, and thus we confirmed the flexibility of GP regression models. Considering various existing use cases in addition to our novel applications, GP regression can be used to model diverse data sets addressing a wide range of problems. The accuracy of the model depends on the input data and on the set boundary conditions. Generally, high-quality data allow the usage of loose boundary conditions, while low-quality data require more restrictive boundary conditions to avoid overfitting.
La fabrique des normes dans l’orpaillage : entre tentatives de formalisation étatique et autorégulation du secteur, étude du cas des orpailleurs de Vihiga et de Kakamega, à l’ouest du Kenya
Authors: Bohbot Joseph
Published: April 2024

Depuis 2010, l’activité minière est en pleine expansion à l’Ouest du Kenya et notamment dans les comtés de Vihiga et de Kakamega. Face au dynamisme de l’orpaillage, l’État kenyan s’est lancé dans une politique de formalisation de la mine artisanale à travers la refonte du code minier de 2016. Aujourd’hui, cette politique ne trouve pas d’application concrète sur le terrain. Il en est de même pour les programmes de développement, notamment celui du PNUD et du FEM consacré à l’orpaillage. Dans une dynamique inverse, des initiatives informelles de régulations portées par les orpailleurs rencontrent un certain succès dans l’encadrement de l’activité. Cette absence de résultats interroge sur les tensions et les renégociations entre normes officielles, normes pratiques et le positionnement des acteurs institutionnels, notamment ceux impliqués sur le terrain.
Black Guernica sur un petit site d’or au Burkina Faso
Authors: Cros Michèle
Published: April 2024

Dans cet article, résolument descriptif, il s’agit de rendre compte, à l’aide de dessins collectés en pays lobi burkinabè d’un passage à l’acte fort violent sur une petite mine d’or artisanale dans le sud-ouest du Burkina Faso. L’affrontement s’est passé le 30 octobre 2017. Plusieurs orpailleurs y ont trouvé la mort et le marché du site a été incendié par les autochtones de la région. Quel en est le facteur déclenchant ? L’accident qui a coûté la vie à une femme Lobi ne prend sens qu’inséré dans un enchaînement mortifère qui blesse une même famille vivant dans un village frontalier de ce site. Au «  notre sang a été versé  » du côté Lobi répond une nécessité d’en découdre avec le collectif des orpailleurs. En arrière-plan symbolique, figure le rappel du caractère honorifique qui s’attache à l’exercice de la vengeance jugée «  légitime  » lorsqu’il s’agit d’éteindre une dette de sang y compris de nos jours, en contexte de boom minier.
Les deux visages de Janus de l’orpaillage illégal en Côte d’Ivoire : entre prospérité relative et insécurité humaine
Authors: Guipié Gérard Eddie Marc
Published: April 2024

La présente étude repose sur une méthode qualitative et des entretiens semi-directifs. Elle présente un état des lieux de l’orpaillage illégal en Côte d’Ivoire. Pratiqué intensément depuis deux décennies, l’orpaillage semble irrépressiblement lié à la grammaire de la négativité avec son cortège de conflits communautaires, de pollutions environnementales et présentant de forts risques de collusion avec le terrorisme. Cependant à rebours des considérations dominantes, dans un contexte rural marqué par une paupérisation des populations, l’orpaillage illégal bien que réprimé par les pouvoirs publics devient une véritable «  aubaine économique  » qui fait l’objet d’une gouvernance communautaire, source de paix (négative) et même de prospérité relative.
Orpaillage et genre : (re)questionner la division sexuée du travail sur le site d’orpaillage de Tourela (Mali)
Authors: Coulibaly Fatoumata
Published: April 2024

Les chercheurs d’or affluent de tous côtés sur les sites aurifères du Mali. Beaucoup de jeunes, des hommes, mais aussi des femmes. Quoique les tâches qui sont réservées à ces dernières soient souvent subalternes ou périphériques, les revenus qu’elles en tirent peuvent être importants. Cela donne aux femmes la possibilité de renégocier leur place dans une société pourtant très patriarcale, et de refuser les travaux de «  bonnes  » auxquels elles étaient généralement confinées.
« Objectif irrigation » : actions de développement, dynamiques agricoles et pratiques de la migration dans la région de Tahoua (Niger)
Authors: Populin Martha , Sambo Bode , Andres Ludovic
Published: April 2024

Depuis l’époque coloniale, les habitants de la région de Tahoua (Niger) pratiquent la migration circulaire, surtout vers la Libye et le Golfe de Guinée. Depuis les années 2000, l’essor de l’irrigation, l’arrivée de grands projets de développement et la dégradation des conditions de sécurité dans les pays de destination modifient leurs pratiques migratoires. La «  migration  » a été remplacée par l’«  irrigation  » comme principal objectif des jeunes hommes. Cependant, des interrelations existent entre ces deux pratiques, ainsi qu’avec la participation aux activités des projets de développement.
L’héritage français de « la science politique africaine francophone » : le cas du Cameroun
Authors: Etoh Ekwoneng Estelle
Published: April 2024

Cet article analyse l’influence de l’héritage français sur la science politique africaine. Il s’agit, à travers l’exemple du Cameroun, de comprendre le processus d’ancrage de la science politique française dans les pays de l’Afrique subsaharienne. Comment comprendre le rapport entre le legs français et la science politique africaine ? Quel est l’impact de cet héritage sur le développement de la discipline en Afrique ? Comment la science politique africaine se territorialise-t-elle ? L’on relève que dès son institutionnalisation en Afrique, la science politique a été marquée par «  le poids de l’héritage culturel français  » : c’est la science politique dominée. Cette entreprise de perpétuation porte «  l’odeur du père  » du fait des référents situés. Cependant, ce processus d’universalisation inhérente à l’évolution du monde se heurte à des concessions bigarrées sur les différents territoires de la greffe, ce qui a des effets sur le rayonnement de la discipline en Afrique. Ces tentatives de réappropriation à l’œuvre laissent entrevoir la construction progressive de l’identité d’une science politique camerounaise et africaine. La méthodologie articule des données qualitatives et quantitatives, issues de l’analyse documentaire, des entretiens et du sondage d’opinion. Cet arsenal est adossé sur le néoinstitutionnalisme et la théorie bourdieusienne du champ.
Le syllogisme sophistique selon Simon de Faversham et Raoul le Breton : entre formalisme et pragmatique
Authors: Emamzadah Parwana , Mora-Márquez Ana María
Published: April 2024

L’objectif de cet article est de montrer qu’à la fin du xiii e siècle un tournant s’est opéré dans la compréhension de la nature du syllogisme sophistique, allant d’une définition axée sur ses caractéristiques formelles vers une définition tenant compte de ses caractéristiques pragmatiques. La première position est celle de Simon de Faversham, développée vers 1280 et probablement durant son séjour à la Faculté des arts de Paris. La seconde position est celle de Raoul le Breton, dernier des plus grands maîtres ès arts parisien. C’est dans leurs réponses respectives que se révèle leur désaccord sur la manière de concevoir le syllogisme sophistique.