Miracle-dz/UniFAR-FTUs huggingface dataset:
WHAT DRIVES THE CHOICE OF SEED STORAGE STRUCTURES? EVIDENCE FROM CERTIFIED MAIZE TRADERS IN GHANA

Research background : Quality maize seed is a necessity to meet the ever-increasing demand for maize production for domestic and commercial uses in Ghana. The need for appropriate storage structures to maintain quality seeds is essential to attain food security and poverty reduction. Proper storage ensures that the gains of seed breeding programmes are maintained. It also maximizes profits through an increase in the quantity, quality, and a reduction in the commercial loss of seeds Purpose of the article : Research in the seed value chain in Ghana has concentrated on farmers with lesser emphasis on the activities of seed traders although they are a critical link between seed producers and farmers. The infrastructure available for their trade has a telling effect on the seeds they offer for sale. This study investigates the type of seed storage structures used by maize seed traders in the Brong Ahafo Region. Factors that affected their choice were also examined. Methods : We made a total population sampling of 82 certified maize seed traders across 8 districts in the region. A discrete choice model is used to examine the traders’ choice of storage structures, as well as the determinants influencing their choice.
Formation of population III stars and pregalactic evolution

On discute de la formation et de l'evolution de la premiere generation d'etoiles (population III) dans l'hypothese ou les fluctuations originelles ont une composante isotherme. On discute des raisons pour lesquelles la fragmentation est improbable avant que les forces centrifuges ne stoppent l'effondrement et que des disques denses se forment. Le disque se forme a 10 4 K mais une petite quantite de H 2 provoque son refroidissement a 1000 K, permettant la fragmentation en masses aussi petites que ≤0,2 M ○. Selon ce scenario, la plus grande part de la masse cachee se trouverait dans des etoiles de tres faible masse, mais une petite fraction de cette masse serait dans des objets tres massifs. On discute des implications cosmologiques du modele
Polarization dynamics in vertical-cavity surface-emitting lasers with optical feedback through a quarter-wave plate

Square-wave switching of the intensities of the orthogonal linearly polarized components of the output of a vertical-cavity surface-emitting laser(VCSEL) found previously in experiments with polarization-changing optical feedback, is not found in rate equation models incorporating only birefringence and gain anisotropy, but is found in the model for VCSELs developed by San Miguel, Feng, and Moloney [M. San Miguel, Q. Feng, and J. V. Moloney, Phys. Rev. A 52, 1729 (1995)]. The dynamics is sensitive to both the feedback strength and the relaxation rate of the magnetization in the quantum well sublevels.
Acceptance of Internet Banking in Bangladesh: Evidence from Bangladesh

 Abstract — The high penetration and adoption of internet in Bangladesh has given rise to huge investments in Internet Banking. Unlike the foreign banks, internet-based banking has only recently been introduced by some of the major private banks and national banks. Although many banks have invested heavily in internet banking, the adoption of internet banking is currently not as expected. This paper aims to explore the antecedents in determining the acceptance of Internet Banking in Bangladesh. Findings suggest that internet banking use increases if the bank‟s customers perceive that it is not risky, the credibility of the bank is good, and it is easy to use, leading to increased acceptance of internet banking. Therefore, I propose that banks should promote the availability of internet banking, reduce the risks associated, and make the technology user friendly so that banks can benefit financially and at the same time provide better services to their customers.
Waveguide Parameters of 19.8 kHz Signal Propagating over a Long Path

The amplitude and phase of 19.8 kHz signal from navigational transmitter located in North West Cape, Australia, recorded at Suva, Fiji, have been utilized to determine the waveguide mode parameters. The propagation path is mixed over land and sea having Transmitter-Receiver Great Circle Path distance 6.7 Mm. The experimental values of the parameters were found to be consistent with the theoretical values calculated using the mode theory of VLF wave propagation in the waveguide.
Damage Model for Concrete Using Bounding Surface Concept

A continuum damage mechanics model for monotonic and cyclic behavior of concrete is developed. The model adopts a bounding surface concept in which the introduced bounding surface, loading surface, and initial fracture surface are chosen to be functions of the maximum accumulated damage ever experienced by the material. The initial fracture surface is the onset of fracture propagation, i.e., damage growth occurs only when the loading surface lies outside the initial fracture surface. The proposed model recognizes the different behavior of concrete in tension and compression, hence the damage due to tensile stresses is assumed to grow independently from the damage due to compressive stresses and separate compliance matrices are introduced for tension and compression. Both hardening and softening behavior of concrete are displayed by the proposed damage‐bounding surface. The model successfully predicts the essential characteristics of concrete behavior such as the nonlinearity, stiffness degradation, shear .
Prediction model of intention to use digital fitness services for health promotion during the COVID-19 pandemic: a gender-based multi-group analysis

As the number of people infected with COVID-19 in Korea is increasing, several measures have been implemented to gradually restrict outdoor activities and indoor gatherings while promoting a non-face-to-face social culture. In this study, we performed a gender-based multi-group analysis using a technology acceptance model (TAM) as an external variable for COVID-19 risk perception to verify the model’s predictive ability to increase participation behavior toward digital fitness services. We analyzed the data of 433 Koreans using an online survey consisting of 23 items. A structural equation model was used to verify the perceived ease of use (PEOU), perceived usefulness (PU), intention to use and exercise participation behavior of the TAM with COVID-19 risk perception as an external variable. First, our results showed that COVID-19 risk perception had a statistically higher significant and positive effect on PEOU (β = 0.170, t = 3.296, p < 0.001) than on PU (β = 0.130, t = 2.848, p = 0.004) of digital fitness services. Second, the PEOU of the digital fitness service was found to have a statistically higher significant positive effect on PU (β = 0.512, t = 9.728, p < 0.001) than on intention to use (β = 0.130, t = −2.774, p = 0.006). Third, the PU of digital fitness services was found to have a statistically significant positive effect on the intention to use (β = 0.684, t = 12.909, p < 0.001). Fourth, the intention to use the digital fitness service was found to have a statistically significant positive effect on exercise participation behavior (β = 0.796, t = 16.248, p < 0.001). Lastly, we observed a significant difference between men and women in COVID-19 risk perception and PEOU among the six paths established. Digital environments that encourage participation in exercises could promote health during a pandemic. This study highlighted the need to consider digital environments that encourage exercise participation in creating physical exercise contents as there was no significant difference in the intention to use digital fitness services between men and women.
FREE SUBGROUPS IN THE GROUP OF UNITS OF A TWISTED GROUP ALGEBRA

Consider a twisted group algebra K t G of a torsion group G over a field K. Provided K is sufficiently large, then either K t G is commutative or U(K t G) contains a noncommutative free group. *Research partially supported by CNPq. †Research partially supported by CNPq, by FAPESP Proc. 96/4505–2 and MCT/FINEP, Projeto PRONEX 107/97.
A BLACK HOLE IN THE X-RAY NOVA OPHIUCHI 1997

We have obtained 18 moderate-resolution (~2.5 Angstroms) spectra of the Galactic X-ray Nova Ophiuchi 1977 in quiescence with the first of the W. M. Keck 10 m telescopes. Cross-correlation with the spectra of late-type dwarfs (especially K7) yields excellent radial velocities for the companion star. The orbital period (P) is 0.5229 ± 0.0044 d, and the semiamplitude (Kc) is 447.6 ± 3.9 km s-1; these are consistent with the values previously derived by Remillard et al. (1996) from CTIO photometry (P = 0.5213 ± 0.0013 d) and spectroscopy (Kc = 420 ± 30 km s-1). Our derived mass function, f(Mx) = PKc3/2 pi G, is 4.86 ± 0.13 Modot (cf. 4.0 ± 0.8, Remillard et al.), the third highest known for any low-mass X-ray binary. Being considerably above the conventional limiting mass for a neutron star (~3.2 Modot), it strongly suggests that the compact primary is a black hole. Plausible mass estimates based on an inclination i = 70circ (from ellipsoidal modulations) and Mc = 0.3-0.6 Modot are Mx = 6.4-6.9 Modot.
On asymptotic stability of solitary waves in discrete Klein–Gordon equation coupled to a nonlinear oscillator

The long-time asymptotics is analysed for finite energy solutions of the 1D discrete Klein–Gordon equation coupled to a nonlinear oscillator. The coupled system is invariant with respect to the phase rotation group U(1). For initial states close to a solitary wave, the solution converges to a sum of another solitary wave and dispersive wave which is a solution to the free Klein–Gordon equation. The proofs develop the strategy of Buslaev–Perelman: the linearization of the dynamics on the solitary manifold, the symplectic orthogonal projection, method of majorants, etc.
Long-lived disc accretion in the η Chamaeleontis pre-main sequence star cluster

High-resolution spectroscopic study of late-type members of the ≈9-Myr-old η Chamaeleontis star cluster shows that four stars, RECX 5, 9, 11 and ECHA J0843.3–7905, have broad Hα profiles indicative of ballistic accretion of material from circumstellar discs first identified by virtue of their infrared (IR) excess emission. Quantitative analysis of the profiles finds accretion in η Cha stars at rates comparable to that derived by Muzerolle et al. for members of the similarly aged TW Hydrae Association (TWA); rates 1–3 orders of magnitude lower than in younger classical T Tauri (CTT) stars. Together these studies indicate that the fraction of long-lived inner discs can be significantly higher than that inferred from study of younger pre-main sequence (PMS) populations, which suggest a disc lifetime of <6 Myr. The detection of long-lived discs may have implications for the formation of planetary systems. If slow accretion processes are the dominant formation mechanism for Jovian planets then long-lived discs may be ideal sites to search for evidence for protoplanets.
Prior infection- and/or vaccine-induced protection against Omicron BA.1, BA.2 and BA.4/BA.5-related hospitalisations in older adults: a test-negative case-control study in Quebec, Canada

Background. Due to severe outcomes, elderly adults 60 years or older are prioritized for COVID-19 vaccination but accumulated SARS-CoV-2 infection and vaccination likely modifies their risk. We estimated vaccine effectiveness against omicron-associated hospitalisation among elderly adults, by number of doses, prior infection history and time since last immunological event. Methods. We conducted a test-negative case-control study among symptomatic elderly adults tested for SARS-CoV-2 in Quebec, Canada during BA.1-, BA.2- and BA.4/5-dominant periods. Relative to unvaccinated, infection-naive participants, we compared COVID-19 hospitalisation risk by mRNA vaccine dose and/or prior infection (pre-omicron or omicron) history. Findings. During BA.1, BA.2 and BA.4/5 periods, two- vs. four-dose vaccine effectiveness alone against hospitalisation was: 78% (95%CI:75-80) vs. 96% (95%CI:93-98); 60% (95%CI:50-97) vs. 84% (95%CI:81-87); and 40% (95%CI:30-49) vs. 68% (95%CI:63-72), respectively, consistent with longer median time since second vs fourth dose. By respective period, effectiveness of pre-omicron vs. omicron infection alone against hospitalisation was: 93% (95%CI:80-97) vs. [not estimable]; 88% (95%CI:50-97) vs. 96% (95%CI:68-99); and 69% (95%CI:30-85) vs. 90% (95%CI:79-95). Regardless of doses (2-5) or prior infection type, hybrid protection was [≥]90%, lasting at least 6-8 months during the BA.4/5 period. Prior omicron infection alone reduced BA.4/5 hospitalisation risk by >80% for at least 6-8 months. Interpretation. Elderly adults with history of both prior SARS-CoV-2 infection and [≥]2 vaccine doses appear well-protected for a prolonged period against omicron hospitalisation, including BA.4/5. Ensuring infection-naive older adults remain up-to-date with vaccination may further reduce COVID-19 hospitalisations most efficiently. Funding. Ministere de la Sante et des Services sociaux du Quebec.
Age patterns in a sample of spiral galaxies

We present the burst ages for young stellar populations in a sample of six nearby (<10 Mpc) spiral galaxies using a differential pixel-based analysis of the ionized gas emission. We explore this as an alternative approach for connecting large-scale dynamical mechanisms with star formation processes in disc galaxies, based on burst ages derived from the Hα to far-UV (FUV) flux ratio. Images of each galaxy in Hα were taken with Taurus Tunable Filter and matched to FUV imaging from GALEX. The resulting flux ratio provides a robust measure of relative age across the disc which we discuss in terms of the large-scale dynamical motions. Systematic effects such as a variable initial mass function, non-solar metallicities, variable star formation histories (SFHs) and dust attenuation have been used to derive estimates of the systematic uncertainty. The resulting age maps show a wide range of patterns outside of those galaxies with the strongest spiral structure, confirming the idea that star formation is driven one by several processes, largely determined by the individual circumstances of the galaxy. Generally, grand design spirals such as M74, M100 and M51 exhibit age gradients across the main spiral arms, with the youngest star formation regions along the central and inner edges. Likewise, in the dominant star-forming complex of IC 2574 or the ring of M94, the most recent star formation is centrally confined to the regions of star formation activity. In M63 and M74 galaxy-wide trends emerge, contrary to the spiral structure in these galaxies, suggesting that spiral density waves are not the dominant driver in some cases. We argue that despite appearances, galaxy morphology is not an absolute discriminator of the SFH of an individual galaxy, nor of the processes triggering it. We conclude that Hα-to-FUV flux ratios are a relatively direct way to probe burst ages across galaxies and infer something of their dynamical histories, provided that sources of systematics are properly taken into account.
Oxygen vacancies effect on ionic conductivity and relaxation phenomenon in undoped and Mn doped PZN-4.5PT single crystals

AC-impedance spectroscopic studies in the temperature range 550–700 °C are carried out on undoped and Mn doped PZN-PT single crystals grown by the flux method. The variation of dielectric permittivity with temperature at different frequencies shows normal ferroelectric and relaxor-like dependence for the doped and undoped crystals, respectively. Temperature-dependent spectroscopic modulus plots reveal a much broader peak for PZN-4.5PT + 1%Mn compared with that for PZN-4.5PT, which is different from the dielectric behaviour of the doped one. Complex modulus imaginary part (Z″) versus real part (Z′) plots fit well with one semicircle thus indicating only bulk contribution. The relaxation observed in the spectroscopic plots was assigned to mobile relaxor species such as oxygen vacancies and ions. No such relaxation could be observed for PZN-4.5PT + 1%Mn in the dielectric measurements. For both undoped and Mn doped crystals, the conduction behaviour was modelled by the universal dynamic response equation and by the NTC (negative temperature coefficient) materials resistance-temperature behaviour. A large difference in behaviour was found between the two single crystals such as the thermistor coefficients and the activation energy values, which could explain the increase in the thermal stability observed in the Mn doped PZN-PT single crystals by many studies.
One-Dimensional Classical Planar Model with Competing Interactions

Exact results for the thermodynamic properties of the one-dimensional classical planar model with competing nearest-neighbor and next-nearest-neighbor interactions are presented. The calculations are performed by extending the numerical transfer-matrix method of the nearest-neighbor problem to allow for next-nearest-neighbor interactions. It is found that, for a certain range of values of the competing interactions, the system exhibits helical short-range order whose characteristic wave-number depends on temperature. The nature of the helical short-range order at low temperatures is discussed in connection with a domain wall between domains of opposing chirality of the helical state.
Simulation of self-compacting concrete (SCC) passing ability using the L-box model for sustainable buildings

The self-compacting concrete (SCC), which is the major innovation of the concrete technology of the 21st century, has been sustained due to its impact on the sustainable construction of infrastructures. Various additives have been coupled into the production of SCC to improve its passing ability, flow, shear stress, dynamic resistance and segregation resistance. The flow of the SCC is experimentally measured through various models, which include Slump-cone, V-funnel, L-box, U-box, J-ring, etc., by which the flowability, passing ratio (passing ability), etc., are determined. In this research paper, the L-box model has been used to simulate the flow output condition, which is the passing ratio (h2/h1) of the SCC, to optimize its passing ability for sustainable concreting. The passing ability of the SCC through the L-box was estimated by recording the heights at the upstream (h1) and downstream (h2) of the horizontal leg of the test box at the end of the flow through embedded steel bars. Stress and pressure boundary conditions for the flow state condition were deployed to solve the passing ratio simulation problem for the L-box model. The results show that the optimized passing ratio (flow output), h2/h1, falls within the appropriate European Guidelines for Self-Compacting Concrete (SCC) materials.
Assessing 3D printing processes as enablers of circular economy

Additive Manufacturing (AM), also popularly known as 3D Printing, refers to a group of manufacturing methods which are guided by a digital model and use incremental addition of material, usually in a layer-by-layer manner, for the fabrication of objects. Lately, AM is widely used in both industry and academia, exhibiting, among others, the advantages of flexibility and ability to produce on demand, with reduced cost, time and waste. This paper seeks to shed light on the contribution of 3D printing in the transition towards the objective of circular economy. Towards this end, we focus on three AM processes (Cold Spray, Direct Energy Deposition, and Powder Bed Fusion), and we review 27 distinct case studies in the laboratory as well as industrial settings, exploring their circularity based on the comprehensive 9R framework (recover, recycle, repurpose, remanufacture, refurbish, repair, reuse, reduce, rethink, refuse). Overall, the results provide a structured assessment of the degree of circularity, and identify the dominant “R” strategies employed by the specific methods of AM. They also reveal the positive impact, and the corresponding advantages, of 3D printing in the extension of product(s) life cycle, with respect to specific material and industry sectors.
Exact solution for the nonlinear pendulum

This paper deals with the nonlinear oscillation of a simple pendulum and presents not only the exact formula for the period but also the exact expression of the angular displacement as a function of the time, the amplitude of oscillations and the angular frequency for small oscillations. This angular displacement is written in terms of the Jacobi elliptic function sn(u;m) using the following initial conditions: the initial angular displacement is different from zero while the initial angular velocity is zero. The angular displacements are plotted using Mathematica, an available symbolic computer program that allows us to plot easily the function obtained. As we will see, even for amplitudes as high as 0.75p (135o) it is possible to use the expression for the angular displacement, but considering the exact expression for the angular frequency w in terms of the complete elliptic integral of the first kind. We can conclude that for amplitudes lower than 135o the periodic motion exhibited by a simple pendulum is practically harmonic but its oscillations are not isochronous (the period is a function of the initial amplitude). We believe that present study may be a suitable and fruitful exercise for teaching and better understanding the behavior of the nonlinear pendulum in advanced undergraduate courses on classical mechanics.
Abundances in the hot DZ star CBS 127 : how efficient is hydrogen screening?

A revised and updated grid of cool helium-rich model atmospheres which includes the effect of varying hydrogen abundance is used to analyze the temperature and abundance of the DZ white dwarf CBS 127. Comparisons of the star to several other DZ white dwarfs with similar T(e)s show that CBS 137 is the hottest DZ star and lies near the boundary temperature above which it has been proposed that hydrogen accretion may be prevented. Based on the results, a specifically defined single lower boundary temperature for screening is rejected, and it is demonstrated that the propeller must operate over a very broad range of T(eff), down to T(eff) as low as 5800 K, with highly variable efficiency. 39 refs.