bluuebunny/crossref_metadata_2025 huggingface dataset:
SOCIAL POLICY FRAMEWORK FOR AFRICA: IMPLICATIONS FOR SOCIAL WORK IN AFRICA
Authors: JONGMAN Dr. KGOMOTSO
Published: November 2024

Social Policy Framework for Africa (2008) has implications for social work practice and education in Africa and beyond. It calls for a progressive social work that is aligned to the logic, substance, and principles of social justice and human rights. Social Policy Framework for Africa advocates for a social work practice and education that has clear philosophical and ideological foundations anchored on social democratic principles and values. These values will revolve around social justice, human rights, sustainable development, collectivism, solidarity, self-sufficiency, empowerment, human security, and faith in democracy. This is in resonance with the global definition of social work as described by the International Federation of Social Work and International Association of Schools of Social work (2014). In this paper, we engage on the social policy framework in African and look at its implication to social work.
CONFLICT MANAGEMENT, HEADS AND SCHOOLS’ DEVELOPMENT COMMITTEES: IMPLICATIONS FOR EDUCATIONAL MANAGEMENT
Authors: PATRICK MAKOMBE , TEMBA MANGWIRO
Published: November 2024

The study was motivated by conflicts between school heads and their School Development
Committees. Such conflicts affected learners’ quality of education contrary to the purpose of
their (SDCs) creation. Since the purpose of such a study is to improve practice, the study was
guided by the pragmatism research philosophy. Pragmatism facilitated the collection of data
using methods contingent with the variable being captured. Mixing qualitative and quantitative
methods enhanced the validity and reliability of the study findings. The population of the study
was composed of teachers and parents who propose and activate school development policies.
Data was gathered from a purposive sample of 57 teachers and 93 parents from Nyanga district.
Such a sample is statistically large enough for the variables to be normally distributed and
findings generalised for similar school environments. Data was captured from a sequence of
document analysis, focus group discussions and in-depth interviews. Questionnaires were used
to provide a record of conflicts and their solutions. The study found that: the major source of
conflict was perceived and real financial misappropriation. This was followed on the rank by
learners' low academic performance. School Development Committee members’ lack of trust
in the School Heads was linked to, School Heads' dominance in decision-making. Party-politics
safeguarded conflict environment within the school. The study recommends the training of
SDC members and their terms can be a maximum of five years rather than one. There is need
for an increased communication between the school and its SDCs. A team-oriented approach
can be inculcated for SDCs to co-own their schools. Regular consultative meetings can be used
to enhance the teaching and resources for the schools. School Heads and their SDCs can use
the party political influences for the infrastructure development. For example, the local MP can
be influenced to source funds for a block of classrooms which can be named after him/her.
Multicomponent synthesis of α-branched amines using organozinc reagents generated from alkyl bromides
Authors: Leroux Baptiste , Beaufils Alexis , Banchini Federico , Jackowski Olivier , Perez-Luna Alejandro , Chemla Fabrice , Presset Marc , Le Gall Erwan
Published: November 2024

The use of alkylzinc bromides in the multicomponent Mannich reaction is described. Heteroleptic organozinc compounds were obtained in THF or 2-MeTHF by direct insertion of zinc dust into the C–Br bond of alkyl bromides. It was found that the presence of a stoichiometric amount of LiCl was essential for the efficiency of the subsequent three-component coupling with aldehydes and amines. A variety of primary, secondary, and tertiary organozinc reagents as well as secondary amines and aromatic aldehydes could be used for the straightforward preparation of α-branched amines. Interestingly, whereas previously reported work describing the preparation and reaction of organozinc iodides in acetonitrile showed higher reactivity of secondary organozinc reagents over primary ones, reactions in THF in the presence of LiCl led to opposite results, with higher reactivity of primary organozinc reagents.
Ethical AI in Retail: Consumer Privacy and Fairness
Authors: Adanyin Anthonette
Published: November 2024

The adoption of artificial intelligence (AI) in retail has significantly transformed the industry, enabling more personalized services and efficient operations. However, the rapid implementation of AI technologies raises ethical concerns, particularly regarding consumer privacy and fairness. This study aims to analyze the ethical challenges of AI applications in retail, explore ways retailers can implement AI technologies ethically while remaining competitive, and provide recommendations on ethical AI practices. A descriptive survey design was used to collect data from 300 respondents across major e-commerce platforms. Data were analyzed using descriptive statistics, including percentages and mean scores. Findings shows a high level of concerns among consumers regarding the amount of personal data collected by AI-driven retail applications, with many expressing a lack of trust in how their data is managed. Also, fairness is another major issue, as a majority believe AI systems do not treat consumers equally, raising concerns about algorithmic bias. It was also found that AI can enhance business competitiveness and efficiency without compromising ethical principles, such as data privacy and fairness. Data privacy and transparency were highlighted as critical areas where retailers need to focus their efforts, indicating a strong demand for stricter data protection protocols and ongoing scrutiny of AI systems. The study concludes that retailers must prioritize transparency, fairness, and data protection when deploying AI systems. The study recommends ensuring transparency in AI processes, conducting regular audits to address biases, incorporating consumer feedback in AI development, and emphasizing consumer data privacy.
The Relationship between Leadership Styles and Organizational Commitment – Exploring the Mediating Effect of Diversity, Equity, and Inclusion (DEI) Practices
Authors: Tsai Cheng-Hua
Published: November 2024

This study explores the impact of Diversity, Equity, and Inclusion (DEI) practices on human resource management in the hospitality industry. It focuses on the relationship between leadership styles and organizational commitment. By scrutinizing the interplay of these elements, the research aims to offer practical insights for addressing labor shortages, enhancing employee satisfaction, and bolstering organizational competitiveness. Key research questions explore the positive influence of DEI practices on leadership styles, their mediating role between leadership styles and organizational commitment, and the distinct mediating effects of Diversity, Equity, and Inclusion. The research concludes that transformational leaders who inspire and motivate their teams foster organizational commitment by promoting inclusive practices. Transactional leaders who focus on clear expectations and rewards indirectly impact commitment by ensuring fair and equitable treatment. The study recommends that organizations invest in leadership development programs emphasizing transformational leadership skills and integrating equity-focused practices. A notable research trend emerging from this study is the concept of an Inclusive Leadership Model, emphasizing the mediating roles of DEI practices in tandem with leadership styles. This research aims to guide the hospitality industry in formulating human resource management strategies and promoting DEI practices.
Graduate Students’ Intrinsic Motivation in Fully Online Courses
Authors: Alahmari Ahmed
Published: November 2024

Despite the emerging research regarding online learning, little attention has been given to students’ intrinsic motivation in online courses. Therefore, this research was conducted to determine the level of students’ intrinsic motivation in fully-online courses environment. (IMeL) questionnaire with 127 graduate level participants was used to answer the research questions which are (1) What is the level of graduate students’ intrinsic motivation in fully online courses? (2) Is there a significant difference in the level of graduate students’ intrinsic motivation in fully online courses in terms of: (gender, registration status, employment status, and experience with fully online courses)? Findings revealed that graduate students had high level of intrinsic of motivation in online courses environment. The study found that there is a statistically significant difference in the level of graduate students’ intrinsic motivation in fully online courses in terms of gender. It was also found that there are no statistically significant differences in the level of graduate students’ intrinsic motivation in fully online courses in terms of registration status, employment status, and experience with fully online courses. More future qualitative method research is needed in order to understand the nature of intrinsic motivation in online learning environment profoundly.
Role of Public Relations in Profit and Non- Profit Organisation in Delta State
Authors: Igben Harvey G.O. , Dorka Onine Better
Published: November 2024

This paper examined the role of public relations in both profit and non-profit organizations in Delta State. In executing this paper descriptive survey design was used in this investigation. The study population is eight hundred and sixteen (816) public relations officers from some selected profit organization and two hundred and eight-five (285) public relations officers from some selected non-profit organization, which make it a total of one thousand, one hundred and one (1101) public relation officers from profit and non-profit organizations in Delta State. The technique used for this study is a simple random sampling technique. The sample size for the study was one hundred and eleven (111) public relations officers. The questionnaire was used as the instrument for collecting data. The statistics used for this study were mean (x ̅). Findings showed that public relations is crucial in profit and non-profit organizations. Findings also show that strategic communication is required for promoting profit and non-profit organizations. Findings show that some challenges facing public relations strategies that drive business outcomes include difficulty building and maintaining relationships with key stakeholders, limited understanding of public relations among stakeholders, difficulty in measuring the effectiveness of PR efforts and limited access to government information and resources. Based on findings, this paper recommended that public relations officers attend workshops, webinars, and conferences to stay informed about the latest public relations and communications developments. Organizations should provide training and resources for public relations professionals to enhance their skills and stay current with industry developments.
Political Misinformation and Disinformation on Social Media: A Study of the 2023 Gubernatorial Election in Lagos State
Authors: Akinsulire Tolulope , Ayorinde Michael , Yekinni Razaq , Ilesanmi Rushdah
Published: November 2024

Social media has emerged as a highly influential platform in various facets of the society, including the political landscape. Although misinformation and disinformation have been present prior to the rise of social media platforms, the emergence and evolution of these platforms have significantly facilitated their dissemination, making it easier to access and spread them across various locations. This study examines political misinformation and disinformation on social media during the 2023 Lagos state gubernatorial elections. The study was anchored on the agenda setting theory, the Survey Research Method was used and the questionnaire administered via google forms served as the instrument of data collection. The study population consisted of residents from Ojo Local Government area, with a sample size of 400 respondents calculated using the Taro Yamane formula. Respondents sampled for this study were selected through purposive sampling technique. Findings showed that citizens were exposed to political misinformation and disinformation on social media during the 2023 Lagos state gubernatorial elections. Findings also revealed that political party social media accounts, news outlets and user comments on social media all served as sources of misinformation and disinformation during the 2023 Lagos state gubernatorial elections. The paper recommends the establishment of media literacy programs that target the public to enhance their critical thinking skills and ability to discern deceptive information on social media platforms.
Analysis of Heat Distribution Processes and Casting Defects Supports 2D Direct Pouring Using CFDs
Authors: Jufri Moh , Daryono Daryono , Hendaryati Heni , Balqis Dhia , Ramadhani Nurul Aisyah , Hery Soegiharto Achmad Fauzan , Syafiq Muhammad
Published: November 2024

Bolster and bogie frame of a train constitute a unified wheel system in both locomotives and non-locomotive cars. The bolster serves as the support for the bogie against the car body. Generally, both the bolster and bogie frame are made of steel construction with AAR Grade B+ cast material, which is categorized as medium carbon steel. In the casting of the bolster, despite hollow molds being made to the exact shape of the final product, often there are occurrences of hollow spots or imperfect shapes due to the challenging control of the cooling and solidification processes. This is caused by improper placement of mold venting channels. This study investigates the process of filling molten metal into the mold, the flow of molten metal, and the solidification process. The research utilizes ANSYS simulation software. The casting simulation method using ANSYS includes the following processes: Pre-Processing, Processing Stage, and Post-Processing. Pre-processing involves the creation of geometries, meshing, determination of parameters, and fluid property determination. The geometry model used is 2D. The Processing Stage includes setting general parameters, model determination, and defining material properties. Post-processing involves presenting and analyzing the obtained results. It can be concluded that the temperature distribution during the casting process to cooling generates a pattern where thicker sections have the highest temperature. Direct pouring gating systems tend to be vulnerable to porosity or hole defects in products because the molten metal comes into direct contact with the mold and it's difficult to control the solidification process.
MHD Natural Convection Flow of Casson Ferrofluid at Lower Stagnation point on a Horizontal Circular Cylinder
Authors: Mohamed Muhammad Khairul Anuar , Ong Huei Ruey , Soid Siti Khuzaimah , Alkasasbeh Hamzeh Taha
Published: November 2024

This study considers the mathematical model of MHD free convection flow on horizontal circular cylinder immersed in Casson ferrofluid, specific to stagnation region. The set of non-linear partial differential equations that governed the model is first transformed to a simpler set of equations using the non-similar transformation. This set of equations then reduced to ordinary partial equations which reflects to the case of stagnation region and solved numerically using the implicit finite difference method known as the Keller-box method. Blood and magnetite are taken as the based-fluid and the ferroparticles for the Casson ferrofluid, respectively. From the numerical study, it was found that the Newtonian ferrofluid with the same Prandtl values had lower thermal and velocity boundary layer thicknesses compared to a Casson ferrofluid. The increase of Casson parameter reduced the thermal boundary layer thickness which physically enhanced the Nusselt number.
Nonlinear Mixed Convective Flow of Darcy-Forchheimer Maxwell Tri-Hybrid Nanofluid Past a Riga Plate
Authors: Anand Kumar Abhilash , Sobhanapuram Sreedhar , Krishna Mangali Veera
Published: November 2024

This contribution aims to explain the nonlinear thermal flow for Darcy-Forchheimer Maxwell  tri-hybrid nanofluid flow over a Riga wedge in the context of boundary slip. Three types of nanomaterials, alumina, Copper and Titania have been mixed into the base fluid known as engine oil. Thermal properties with the effects of porous surface and nonlinear mixed convection have been established for the particular combination. Applying a set of appropriate variables, the couple of equations that evaluated the energy and flow equations was transferred to the non-dimensional form. For numerical computing, the MATLAB software's bvp4c function is used. This article looks at how distinct dimensionless parameters affect the velocity field, temperature distribution, drag force, and Nusselt number. It has been detected that flow rate decay with expansion in porosity parameter and nanoparticles volumetric fractions whereas it rises with wedge angle, Grashof numbers, Darcy-Forchheimer, nonlinear Grashof number and Maxwell fluid parameter. Thermal profiles increase with progress in the heat source, nanoparticles volumetric fractions, viscus dissipation and nonlinear thermal radiation. The percentage increase in skin friction factor is 18.3 and 15.0 when Mh and m take input in the ranges of 0.1 ≤ Mh ≤ 0.3 and 0.1 ≤ m ≤ 0.3.
Water Inlet Behavior in Engine Colling Piping on Indonesian Traditional Wooden Vessel Using CFD Simulation
Authors: Arifuddin Andi Mursid Nugraha , Setiawan Wira , Pamungkas Septian Tommy , Alwi Muhammad Rusydi , Baso Suandar , Firmansyah Mohammad Rizal
Published: November 2024

Traditional wooden boat builders in East Kalimantan make the main engine seawater cooling system by using the water currents created by the movement of the ship without the use of suction pumps. This system has been applied to several wooden ships of various sizes. However, the size of the water flow in the pipe is not known by the builders at each ship's speed. Thus, in this paper, an investigation is carried out on seawater cooling pipes on the behavior of fluids moving in the pipes. This study aims to determine the effect of ship speed on the flow of water that occurs in the cooling pipe (inlet and outlet water). The approach taken in this paper is a computer simulation based on Computational Fluid Dynamics (CFD) by analyzing the current flow (Va) of the water discharge in the cooling pipes at speeds of 1 - 9 knots. CFD can show very detailed results in analyzing fluid flow parameters in pipes. Based on the simulations performed, the average flow velocity has increased by around 14.73% for every 1 knot increase in speed. Meanwhile, the average flow rate will increase on the pipe by 14.78% for every 1 knot increase in speed. For the average pressure obtained, the vertical pipe will increase 25% for every 1 knot increase and the horizontal pipe shell will increase 19.86% for every 1 knot increase. Meanwhile, the recommended minimum ship speed is 2.5 knots to get the required cooling seawater flow rate.
IBM MDM 11.6 Installation: Topology, Software Bundles, Prerequisites, Steps and Issues
Authors: Reddy Anugu Sai
Published: November 2024

The paper provides detailed steps in the MDM installation process, starting from the initial preparation of the installation and addressing the potential challenges. Outlinesthe prerequisites, provisioning servers, users and groups creation, file system requirements, storage, and memory requirements; it highlights the importance of collaboration with the operations teams, Database Administrators (DBA), and WebSphere Application Server(WAS) Administrator, IBM Messaging Queue(MQ) and Infrastructure Architect, Enterprise Architect installation topology, finalization, preparing the Implementation plan, and finalizing the compatible software versions and downloading the MDM software bundles from IBM Support central exacting and sharing with the DBA and WAS Admins and MDM installation steps. And the issues encountered during the installation process.
Zooplankton Diversity of Mustabad Cheruvu, Rajanna Sircilla District, Telangana
Authors: Bhavani Kothapally , Venkatesh G. , Reddy P. Ayodhya , Chari T. Jagadeeshwara , Ram Kumar Dharavath
Published: November 2024

Zooplankton are the crucial role on aquatic ecosystem, they are diverse of group of heterotrophic organisms. They occupy key position in aquatic food web, serving as primary consumers i.e primary consumers that feed on phytoplankton and other microscopic organisms and in turn as food source for large organisms, zooplankton play a role in biogeochemical cycles, particularly in carbon sequestration through the biological pumps. The study has been done for 90days of interval between 9 am to 11am in the month of May to July.
Evaluation of Antioxidant and Anti-Diabetic Potentials of the Ethyl Acetate Leaf Extracts of some Commonly used Medicinal Plants in Ogbomoso, Nigeria
Authors: Ayobami Olakanmi Florence , Temitope Adedosu Olaniyi , Abigeal Ajala Omotayo , Abosede James Busayo , Pelumi Ebenezer Folorunso , Ayodeji Idris Adeniyi
Published: November 2024

Medicinal plants are used as alternatives for treating diabetes mellitus and are considered safe when used alone or combined with synthetic drugs to ensure their effectiveness and also reduced the toxic effects of orthodox medicines. Using in-vitro antioxidant and antidiabetic indices, this study evaluated some commonly used medicinal plants for the treatment and management of diabetes mellitus in Ogbomoso. Four commonly used medicinal plants identified include; Croton zambezicus (CZ), Markhamia tomentose (MT), Asphilia africana (AA), and Albizia ferruginea (AF). The ethyl acetate leaf extracts of the plants were prepared using Soxhlet extraction and dried. Total flavonoid content, percentage 1, 1-diphenyl, 2- picrylhydrazyl (DPPH) and hydroxyl radical (OH) scavenging activity, percentage inhibition of lipid peroxidation, as well as alpha amylase and alpha glucosidase activities, were determined using standard international methods. Total flavonoids content quercetin equivalent (QE) of CZ, MT, AA, and AF obtained, are 170 mg/g QE, 20 mg/g QE, 68 mg/g QE, and 16 mg/g QE respectively in this order CZ >AA>MT>AF at maximum concentrations (400 µg/ml). Percentages of DPPH and OH radical scavenging activities of CZ, MT, AA, and AF are (89.6, 40.7%), (22.83, 35.5%), (16.5, 28.6%), and (31.7, 51.3%) at maximum concentration. The extracts also inhibited lipid peroxidation with these values 56%, 69%, 60% and 72 % at maximum concentration (400 µg/ml). Interestingly, CZ, MT, AA, and AF inhibited alpha amylase and alpha glucosidase activities with these values (21.1, 80.0%), (62.2, 70.9%), (64.2, 63.2%) and (10.5, 85.3%) respectively. Properties exhibited by these plants are antioxidant and anti-diabetics which provide scientific basis for their usage in traditional medicine for the treatment and management of diabetes mellitus in Ogbomoso.
Húsz éve történt: ENSZ magyar rendőri kontingens Kambodzsában, 1992–1993
Authors: Boda József
Published: November 2024

The author describes the experiences of the largest UNTAC mission, involving 22,000 peacekeepers.
The Prevalence of Resonance Among Young, Close-in Planets
Authors: Dai Fei , Goldberg Max , Batygin Konstantin , van Saders Jennifer , Chiang Eugene , Choksi Nick , Li Rixin , Petigura Erik A. , Gilbert Gregory J. , Millholland Sarah C. , Dai Yuan-Zhe , Bouma Luke , Weiss Lauren M. , Winn Joshua N.
Published: November 2024

Multiple planets undergoing disk migration may be captured into a chain of mean-motion resonances with the innermost planet parked near the disk’s inner edge. Subsequent dynamical evolution may disrupt these resonances, leading to the nonresonant configurations typically observed among Kepler planets that are Gyr old. In this scenario, resonant configurations are expected to be more common in younger systems. This prediction can now be tested, thanks to recent discoveries of young planets, in particular those in stellar clusters, by NASA’s TESS mission. We divided the known planetary systems into three age groups: young (<100 Myr old), adolescent (0.1–1 Gyr old), and mature (>1 Gyr old). The fraction of neighboring planet pairs having period ratios within a few percent of a first-order commensurability (e.g., 4:3, 3:2, or 2:1) is 70% ± 15% for young pairs, 24% ± 8% for adolescent pairs, and 15% ± 2% for mature pairs. The fraction of systems with at least one nearly commensurable pair (either first- or second-order) is 86% ± 13% among young systems, 38% ± 12% for adolescent systems, and 23% ± 3% for mature systems. First-order commensurabilities prevail across all age groups, with an admixture of second-order commensurabilities. Commensurabilities are more common in systems with high planet multiplicity and low mutual inclinations. Observed period ratios often deviate from perfect commensurability by ∼1% even among young planets, too large to be explained by resonant repulsion with equilibrium eccentricity tides. We also find that super-Earths in the radius gap (1.5–1.9R
⊕) are less likely to be near-resonant (11.9% ± 2.0%) compared to Earth-sized planets (R

p
< 1R
⊕; 25.3% ± 4.4%) or mini-Neptunes (1.9R
⊕ ≤ R

p
< 2.5R
⊕; 14.4% ± 1.8%).
Impact of Current Uncertainties in the 12C+12C Nuclear Reaction Rate on Intermediate-mass Stars and Massive White Dwarfs
Authors: De Gerónimo Francisco C. , Miller Bertolami Marcelo M. , Battich Tiara , Tang Xiaodong , Catelan Márcio , Córsico Alejandro H. , Li Yunjun , Fang Xiao , Althaus Leandro G.
Published: November 2024

Recent determinations of the total rate of the 12C+12C nuclear reaction show non-negligible differences with the reference reaction rate commonly used in previous stellar simulations. In addition, the current uncertainties in determining each exit channel constitute one of the main uncertainties in shaping the inner structure of super asymptotic giant branch stars that could have a measurable impact on the properties of pulsating ultramassive white dwarfs (WDs). We explore how new determinations of the nuclear reaction rate and its branching ratios affect the evolution of WD progenitors. We show that the current uncertainties in the branching ratios constitute the main uncertainty factor in determining the inner composition of ultramassive WDs and their progenitors. We found that the use of extreme branching ratios leads to differences in the central abundances of 20Ne of at most 17%, which are translated into differences of at most 1.3% and 0.8% in the cooling times and size of the crystallized core, respectively. However, the impact on the pulsation properties is small, less than 1 s for the asymptotic period spacing. We found that the carbon burns partially in the interior of ultramassive WD progenitors within a particular range of masses, leaving a hybrid CONe-core composition in their cores. The evolution of these new kinds of predicted objects differs substantially from the evolution of objects with pure CO cores. Differences in the size of the crystallized core and cooling times of up to 15% and 6%, respectively, lead to distinct patterns in the period spacing distribution.
Plausibility of Capture into High-obliquity States for Exoplanets in the M Dwarf Habitable Zone
Authors: Guerrero Natalia M. , Ballard Sarah A. , Su Yubo
Published: November 2024

For temperate exoplanets orbiting M-dwarf hosts, the proximity of the habitable zone to the star necessitates careful consideration of tidal effects. Spin synchronization of the planetary orbital period and rotation period, tidal locking, and the subsequent impact on surface conditions frames common assumptions about M-dwarf planets. We investigate the plausibility of capture into Cassini State 2 (CS2) for a known sample of 280 multiplanet systems orbiting M-dwarf hosts. This resonance of the spin precession and orbital precession frequencies can excite planets into stable nonzero rotational obliquities, breaking tidal locking and inducing a version of “day” and “night.” Considering each planetary pair and estimating the spin and orbital precession frequencies, we find that 75% of detected planets orbiting M dwarfs may be plausibly excited to a high obliquity and maintain it through subsequent tidal dissipation over long timescales. We also investigate two possible mechanisms for capture into CS2: quantifying the orbital migration or primordial obliquity necessary for CS2. We find orbital migrations by a factor of ≲2 and an isotropic initial spin distribution can produce high-obliquity planets, aligning with similar findings for planets orbiting close-in to FGK dwarfs. Many of the planets in our sample reside in both CS2 and within their stellar habitable zone. Over half of the planets with T
eq < 400 K around host stars with T
eff < 3000 K could possess nonzero obliquity due to residence in CS2. This overlap renders the potential capture into Cassini States extremely relevant to understanding the galaxy’s most common temperate planets.
Adiabatic Mass Loss in Binary Stars. V. Effects of Metallicity and Nonconservative Mass Transfer—Application in High Mass X-Ray Binaries
Authors: Ge Hongwei , Tout Christopher A. , Chen Xuefei , Wang Song , Xiong Jianping , Zhang Lifu , Li Zhenwei , Liu Qingzhong , Han Zhanwen
Published: November 2024

Binary stars are responsible for many unusual astrophysical phenomena, including some important explosive cosmic events. The stability criteria for rapid mass transfer and common-envelope evolution are fundamental to binary star evolution. They determine the mass, mass ratio, and orbital distribution of systems such as X-ray binaries and merging gravitational-wave sources. We use our adiabatic mass-loss model to systematically survey metal-poor and solar-metallicity donor thresholds for dynamical timescale mass transfer. The critical mass ratios q
ad are systematically explored and the impact of metallicity and nonconservative mass transfer are studied. For metal-poor radiative-envelope donors, q
ad are smaller than those for solar-metallicity stars at the same evolutionary stage. However, q
ad do the opposite for convective-envelope donors. Nonconservative mass transfer significantly decreases q
ad for massive donors. This is because it matters how conservative mass transfer is during the thermal timescale phase immediately preceding a delayed dynamical mass transfer. We apply our theoretical predictions to observed high-mass X-ray binaries that have overfilled their Roche lobes and find a good agreement with their mass ratios. Our results can be applied to study individual binary objects or large samples of binary objects with binary population synthesis codes.
Electron Energization by Ion Density Enhancement in the Martian Magnetotail—MAVEN Observations
Authors: Xu Shaosui , Mitchell David L. , Halekas Jasper S. , McFadden James P. , Fowler Christopher M. , Hanley Kathleen , DiBraccio Gina A. , Mazelle Christian , Akbari Hassan , Curry Shannon M.
Published: November 2024

It has been long observed at Mars that electron fluxes are enhanced during the tail current sheet crossings, of which the cause is not well understood. We use a novel approach to reveal one of the electron energization mechanisms with observations from the Mars Atmospheric and Volatile EvolutioN (MAVEN) mission. We find the field-aligned potential, derived from comparing electron distribution functions, to be approximately linearly correlated with the logarithmic values of the local total ion density. This is the expected behavior of an ambipolar electrostatic potential. The large amplitude of potential (tens to hundreds of V) is a result of both a significant density gradient (1 order of magnitude) and the high electron temperature (tens of eV) in the tail. Such a mechanism is not limited to ion density enhancements at current sheet crossings but can be present anywhere that large ion density gradients and hot electrons are present.
The Impact of the War Conflicts on Residential Childcare: A Survey into Czech Children's Homes
Authors: Alois DANĚK
Published: November 2024

The paper's main aim will be to present the research results that mapped the reflection of current war conflicts on the situation in Czech children's homes. We investigated whether ongoing war conflicts are changing the population of children in these institutions and to what extent children's homes are prepared to meet the needs of children from warzones. We worked with a qualitative research design based on close contact with the research setting. We have identified several areas that require attention. In particular, these are issues of religion and socio-cultural norms. We have also identThe paper's main aim will be to present the research results that mapped the reflection of current war conflicts on thesituation in Czech children's homes. We investigated whether ongoing war conflicts are changing the population of children in these institutions and to what extent children's homes are prepared to meet the needs of children from warzones. We worked with a qualitative research design based on close contact with the research setting. We have identified several areas that require attention. In particular, these are issues of religion and socio-cultural norms. We have alsoidentified the need to significantly strengthen the training of teaching staff in the area of skills for working with childre ntraumatized by war and refugee experiences.ifthe need to significantly strengthen the training of teaching staff in the area of skills for working with childre ntraumatized by war and refugee experiences.
Analysis of Migration in the Czech Republic and Security Challenges in the Context of the Current Geopolitical Situation
Authors: Josef ŠENK  , Eliška POLCAROVÁ
Published: November 2024

The article focuses on the analysis of migration in the Czech Republic from several perspectives. A portion of the analysis is dedicated to illegal migration in the Czech Republic, including its structure, main migration routes, and illegal transit migration. It also examines the administrative expulsion of foreigners from the territory of the Czech Republic during the period under review. A comparative study of migration status in relation to the war in Ukraine has focused on the number of refugees entering the Czech Republic, illegal entries, and legal residence of Ukrainian citizens in the Czech Republic, the impacts of migration on internal security and public order, and the state's approach to migration in connection with the refugeeinflux.
Military Versus Civilian University Online Education
Authors: Dana ŘÍHOVÁ  , Marek SEDLAČÍK  , Kamila HASILOVÁ  , Jakub ŠÁCHA  , Tomáš KONDERLA
Published: November 2024

This paper compares online teaching during the Covid-19 pandemic at a military and civilian university. It is based on three independent questionnaire surveys in which respondents rated the quality, advantages, and disadvantages of online instruction relative to face-to-face instruction and indicated which type of learning they preferred. The dat a obtained were processed using the descriptive statistics and the cluster analysis. The results show similar perceptions of the pros and cons of online learning at both types of universities. When evaluating online learning, military students showed similarities only to civilian upper-level students and were more accepting of such learning.
Teaching in Software Applications: A Single Robust Built-In Command versus Sequence of More Elementary Commands
Authors: Vojtěch RŮŽIČKA  , Jiří JÁNSKÝ  , Jan JEKL
Published: November 2024

We investigate several exercises from the two fundamental disciplines of applied mathematics. We process the exercises in the software applications Maple and MATLAB: the exercises in Maple are from numerical analysis and the exercises in MATLAB are from statistics. For each example, we provide two ways of solution (not two different solutions) and try to explore their advantages and disadvantages for teaching students of university technical fields (undergraduate level). We pit solutions against each other: the first way of solution uses pre-prepared functions (robust built-in commands) for fundamental methods of given disciplines; in the second way of solution we have to “program” these methods by using sequences of fundamental commands. In the process, we theoretically establish parameter of education that needs to be carefully balanced for students’ success. However, we are not only thinking about how well the students pass the subject if we use this or that way of solution. We also want to reflect on what we expect and what it is expected that students should learn. Which of the ways will provide them with a more “suitable” type of education for their further development? It seems that with advancing technologies (constantly expanding computing power, the current boom in AI) some of our positions about teaching in software applications need to be re -evaluated – is it really so, or is it just an illusion and the fundamental practices remain valid and they just adapt to new environments? Specifically, for us: Is it still necessary to understand what applications do, or is it enough to remember how to interpret their various outputs? Finally, let us note that we also pay attention to how challenging it is, even for us teachers, to find out what a given robust command actually calculates.
Feasibility of Casualty Evacuation by Unmanned Systems
Authors: František GUBÁŠ
Published: November 2024

Development of unmanned systems has registered unprecedented progress. They provide a wide range of tasks incontemporary battlefields and the process of finding their new applications is still ongoing. Medical support is one ofthe areas where unmanned systems have found their application as well. The aim of the paper was therefore to carryout research on feasibility of casualty evacuation (CASEVAC) by unmanned systems. Research was executed asqualitative research using methods of analysis, observation, personal experience, comparison and generalization tocomprehensively describe different aspects of CASEVAC executed by unmanned systems. Furthermore, as and quantitativeresearch using method of comparison focused on multiple parameters of unmanned systems that are essential requirementsfor fulfillment of CASEVAC tasks. Research process started with study of available documents concerning unmannedsystems their analysis based on personal experience and identification of factors that influence feasibility of CASEVAC byunmanned systems. Furthermore, we compared multiple parameters of different unmanned system solutions with requiredones and identified suitable solutions. We found out that beside unmanned aerial systems that were traditionally deliberatedfor CASEVAC tasks great development of unmanned ground and aquatic systems has been achieved. The feasibility ofunmanned systems for CASEVAC was confirmed and areas of further development have been identified. The papercomprehensively analyzes a variety of aspects that have to be taken into account when considering execution of CASEVACby unmanned systems and sort them into categories.
Base indexes for marine communities in the southern Gulf of Mexico derived from shrimp-fishery data
Authors: Miranda Julia Ramos , Wakida-Kusunoki Armando T. , Flores Hernández Domingo , Gómez Criollo Francisco , Quiroga Brahms Cecilia , Ramos Hernández Rafael , Rojas-González Ramón Isaac
Published: November 2024

In Mexico, shrimp is the most important fishing resource in terms of value, and second in production. Ten percent of the country's production comes from catches in the southern Gulf of Mexico. Several studies report the number of marine species recorded in this zone; however, few consider bycatch, and still fewer determine biodiversity indexes. This work identified the species captured in shrimp trawls from 22 commercial fishing trips from August 2016 to December 2017 in the south of the Gulf of Mexico. Four indexes of taxonomic diversity were determined: richness, evenness, average taxonomic distinctness, and variation. The indexes were calculated by season (dry, rainy, and northerly), spatial scale (terrigenous, carbonate, and Contoy zones), and depth interval: 1 (<10 m), 2 (10-20 m), 3 (20-40 m), and 4 (>40 m). The zones were separated according to the sedimentological characteristics described in the literature, and the depth ranges were arbitrarily defined considering the bathymetry of the zone. Nine classes, 51 orders, 121 families, 207 genera, and 334 species (152 terrigenous, 289 carbonates, and 76 Contoy) were recorded. Evenness index was highest in Contoy (0.75), followed by the terrigenous (0.54) and carbonate zones (0.35). Average taxonomic distinctness was greater in the carbonate (83.51) zone, followed by the Contoy (75.83) and terrigenous (74.55) zones. Contoy was identified as the most variable based on taxonomic distinctness (301.1). Also, the same index calculated by depth stratum and zone showed that the deeper zones generally have more phylogenetic relationships. The determinations of these indexes are proposed and can be used as points of reference to assess the variation and status of marine communities in the region.
Brachyura megalopae in the Jamapa River estuary, Veracruz, southwestern of the Gulf of Mexico
Authors: Cházaro-Olvera Sergio , Rocher-González Andrea , Montoya-Mendoza Jesús , Lango-Reynoso Fabiola , Castañeda-Chávez María del Refugio
Published: November 2024

The present study analyzes the diversity and abundance of infraorder Brachyura megalopae and their relationship with the environmental factors in the Jamapa River estuary, Veracruz, México. The environmental factors of dissolved oxygen, water temperature, total dissolved solids, pH, and salinity were measured. Crabs were captured using light traps and shrimp bait. The generalized linear model was used to determine the relationship between the environmental factors and the five sampling months and the five sampling sites and was used to determine the relationship between the abundance of the megalopae and the sampling months, sites, and environmental factors. A total of 5398 megalopae belonging to seven species of Brachyura were collected. The most abundant species were Minuca vocator and M. burgersi, with 2174 and 2156 megalopae, respectively; these species are common in low-salinity estuaries. The highest diversity was found at the southern boundary of the estuary with six species, 2.24 bits ind-1. The statistical analyses showed that the values of the environmental factors related to the climatic season determine (i.e. temperature and salinity) the abundance of the megalopae. Based on the diversity values evaluated, it can be established that the Jamapa River estuary has intermediate stability.
Ciliate diversity in a backyard fish farm from Zimatlán de Álvarez, Oaxaca Mexico: an island of aquatic microscopic biodiversity from a semi-urban area
Authors: Rivas-Beltrán Martín , Islas-Ortega Alma G. , Contreras-Medina Raúl , Aguilar-Aguilar Rogelio
Published: November 2024

Ciliates are extremely versatile single-celled eukaryotes displaying an enormous functional diversity as key elements of food webs. In this study, we found the ciliates in an artisanal backyard Nile tilapia Oreochromis niloticus farm in Oaxaca, Mexico, to describe the diversity and species distribution. Twenty nominal taxa were recorded inhabiting the studied fish farm; only the species Trichodina centrostrigeata was found parasitizing the gills of the cultured Nile tilapia. Most ciliate species recorded here are indicators of α or β mesosaprobic waters, suggesting that bacteriophage taxa dominate ciliate composition. This study represents the first record of ciliate diversity from an aquaculture farm in Mexico.
Sustainable alternative for the use of invasive species of golden mussel (Limnoperna fortunei) in the feeding of Nile tilapia (Oreochromis niloticus)
Authors: Mansano Cleber Fernando Menegasso , Pereira Bianca Caroline Araujo , Gonçalves Giovani Sampaio , Américo-Pinheiro Juliana Heloisa Pinê , Vanzela Luiz Sergio , Navarrete Acacio Aparecido , Correia Lígia Gabriela , Macente Beatrice Ingrid , Nascimento Thiago Matias Torres
Published: November 2024

The aquaculture of Nile tilapia (Oreochromis niloticus) in cages has faced problems with invading golden mussels (Limnoperna fortunei), an exotic species that shows uncontrolled dissemination. A possible use of golden mussel flour as a fish feed ingredient is investigated in this study. The assessment as food ingredient includes the description of the raw material processing and the analysis of the performance of Nile tilapia, submitted to diets containing different proportions of golden mussel flour, substituting for the traditional source of calcium in fish feeds. The mussels were collected in a fish farm in the northwest of the State of São Paulo and processed in the laboratory. The diets were prepared with different mussel flour proportions (0, 0.35, 0.68, 1.35, and 2.69%). One hundred fifty Nile tilapia fingerlings weighing 4.69 g were distributed in 15 tanks of 150 L. Neither heavy metals nor total coliforms were detected in the analyses of the golden mussel. The chemical-bromatological composition of golden mussels presented 13.41% crude protein, 1.47% ether extract, 30.58% calcium, and 0.20% phosphorus. Golden mussel flour proved an excellent substitute for limestone, yielding similar results concerning the zootechnical variables and better results regarding body composition variables. Despite the successful use of golden mussel flour as a food ingredient, it may not be the final solution for the problems caused by the mollusk. In any case, controlling its dissemination in nature can be an efficient and sustainable method.
Age estimation and individual growth of dwarf hake Merluccius productus along the southernmost limit of the Baja California Peninsula
Authors: Mora-Zamacona Pablo , Salinas-Mayoral César Augusto , González-Peláez Sergio Scarry , Salinas-Zavala César Augusto
Published: November 2024

The Pacific hake Merluccius productus is a commercially important species on the west coast of North America. A non-exploited population south of the Baja California Peninsula known as dwarf hake, from which little is known, has been described. The present study analyzed the age and growth of the dwarf hake off the west coast of Baja California Sur, Mexico. A subsample of 240 otoliths and standard length (SL) data from 932 specimens captured from May to December 2015 was used. The annual formation of increments in otoliths was verified by marginal increment ratio and edge analysis. Age was estimated from transversal sectioned otolith annuli counts, and SL growth was analyzed using a multimodel inference approach. The von Bertalanffy growth model (VBGM), generalized VBGM, Gompertz, logistic, and Johnson growth models were fitted to observed and back-calculated length-at-age data sets grouped by sex. SL records ranged from 11.5 to 27.5 cm, where females reached a larger size and older ages than males. The age structure was well represented for the first six years, with a mode at three years age class and maximum longevity registered in a female of 10 years. According to Akaike's information criterion, the generalized VBGM was most appropriate for females (L∞ = 31.36 cm, k = 0.15), while VBGM provided the best fit for males (L∞ = 25.35 cm, k = 0.28 cm yr-1). The parameter values suggest that the dwarf hake is a fast-growing, small-size fish. These results provide the first estimated growth parameters for the dwarf hake off the southernmost limit of the Baja California Peninsula.