bluuebunny/crossref_metadata_2025_split huggingface dataset:
Factors Influencing Parents’ Decision to Select Primary School in Colombo District, Sri Lanka
Authors: Vindula H. R. A. S. , Madhuwanthi L. A. Pavithra 
Published: May 2022

Aim: This study aims to examine the factors influencing parents’ decision to select a primary school in the Colombo district in Sri Lanka. Accordingly, the study particularly examines the household characteristics and school characteristics influencing parents' decision to select a primary school in the Colombo district.
Methodology: This is a quantitative study that employed a sample of 146 parents in the Colombo district. Half of the respondents have been chosen from public schools whilst the other half were from private schools in the Colombo district. A self-administered survey questionnaire was distributed to collect data and the logistic regression method was used for data analysis.
Results: According to the estimated marginal effects (probabilities) of the final logit model, the school that parents attended and perceived academic performance had a positive effect on parents’ selection of a public school. In contrast, family income and discipline of the school had a negative effect on parents’ selection of a public school.
Conclusion: Perceived academic performance and discipline of the school were the significant school characteristics influencing the parents’ decision to select a primary school while the parent being a past pupil of the school and family income were significant household factors.
Growth and Yield Characteristics of Two Sweet Potato (Ipomoea batatas L.) Varieties as Influenced by Organic and Inorganic Fertilizer Application
Authors: Nyarko Albert , Sarkodie-Addo Joseph , Adofo Kwadwo , Quaye Michael Odenkey , Adu Joseph 
Published: May 2022

A field experiment was conducted at the Crops Research Institute (CRI) at Fumesua – Kumasi from August to December, 2017. The research was to investigate the growth and yield characteristics of sweet potato (Ipomoea batatas L) to the application of organic manure (poultry manure and cow dung) and inorganic fertilizer (NPK, 15-15-15, 300kg/ha) and their combinations. The experiment was a 2x3 factorial with treatments arranged in randomized complete block design (RCBD) with three replicates. The treatments were: sole poultry manure (6t/ha); sole cow dung (8t/ha); sole NPK45-45-45kg/ha; NPK, 22.5-22.5-22.5kg/ha + Poultry manure (PM) (3t/ha); NPK, 22.5-22.5-22.5kg/ha + Cow dung(CD) (4t/ha); NPK, 33.75-33.75-33.75kg/ha + PM (1.5t/ha); NPK, 33.75-33.75-33.75kg/ha + CD (2t/ha); NPK, 7.5-7.5-7.5kg/ha +PM (4.5t/ha); NPK, 7.5-7.5-7.5kg/ha + CD (6t/ha); and no fertilizer amendment (control). Two sweet potato varieties, ‘Apomuden’ and ‘Santom Pona’ were used. The results indicated that on the average, the organic manure and the inorganic fertilizer combinations promoted greater growth than the sole applications and the control. The greatest marketable root yield (14.8 t/ha) obtained from 7.5-7.5-7.5 NPK + 4.5 t/ha PM. For root dry matter, NPK 22.5-22.5-22.5 + CD (4t/ha); NPK 22.5-22.5-22.5 + PM (3t/ha); and NPK 7.5-7.5-7.5 + CD (6t/ha) produced the greatest responses (32.6%, 31.1%, and 30.9%) respectively. Integrated application of organic manure and inorganic fertilizers is thus recommended for improved sweet potato production.
Nutritional and Anti-nutritional Compositions of the Leaves and Stem Bark of Ficus glumosa
Authors: Akinsola A. F. , Osasona I. , Aribisala A. I. 
Published: May 2022

Aim: To evaluate the proximate, mineral, anti-nutritional and amino acid compositions of Ficus glumosa leaves and stem bark.
Place and Duration of Study: The proximate, mineral and anti-nutritional compositions were determined in the Chemistry Laboratory of Ekiti State University, Ado – Ekiti while the amino acid was determined at the Analytical Laboratory of Multi-Environmental Management Consultant, Lagos, Nigeria. The research was carried out between November 2020 and September 2021.
Methodology: All investigations were carried out using well established analytical procedures. Amino acid analysis was carried out through ion exchange chromatography (IEC) using the Technicon Sequential Multisample (TSM) Amino Acid Analyser.
Results: The results revealed that the leaves and the stem bark of Ficus glumosa had moisture contents of 9.78 and 9.67% respectively. Crude protein of 18.8% was recorded for the leaves while 7.73% was recorded for the stem bark. The leaves were observed to contain higher mineral contents than the stem bark. Na/K ratios were 0.048 (leaves) and 0.09 (stem bark). Out of the four anti-nutrients evaluated for the leaves and stem bark, tannins recorded the highest values of 5.42 and 12.5 (mgTAE/g) respectively. Amino acid compositions showed that the leaves and the stem bark contained a total of 95.2 and 83.4 g/100g cp amino acids respectively. Highest concentrated amino acid was Glu with 12.8g/100g cp and 16.2g/100g cp for both leaves and stem bark. Essential amino acid (with His) was 44.9g/100g cp (47.2%) for the leaves and 37.2g/100g cp (44.6%) for the stem bark.
Conclusion: The leaves and stem bark of Ficus glumosa contained appreciable amount of crude protein, important mineral elements and essential amino acids which could contribute to alleviating the problem of protein malnutrition in developing countries.
Evaluation of the Efficacy of Topical Minoxidil in Treatment of Male Androgenetic Alopecia
Authors: Elshebiny Nehal Mohamed , Hassan Ghada Fawzy Rezk , Hasby Eiman Adel , Hodeib Abeer Abd El-hakam 
Published: May 2022

Aims: This study was conducted to evaluate the efficacy of topical minoxidil 5% in treating male androgenetic alopecia.
Study Design: A prospective, randomized study
Place and Duration of study: Outpatient clinic of Dermatology and Venereology Department, Tanta University Hospitals between January 2020 and March 2021.
Methodology: 15 male patients with androgenetic alopecia (age range 23 – 31 years) were included and received topical minoxidil 5% (twice daily) for 24 weeks. Efficacy of treatment was assessed clinically, trichoscopically, and by histopathology (H&E stain).
Results: Patients were classified between grades Ⅲ- Ⅵ at baseline, after 24 weeks of treatment: patients were classified between grades Ⅱ- Ⅴ A. There was an improvement in 60% of patients with no statistically significant difference in the clinical grading before and after treatment. The statistical significance was apparent in the percentage of the terminal and vellus hair and hair density and width after treatment. There were 31.7% and 42.56% increases in hair density and width, respectively. There was a decrease in the miniaturized hair follicles and perifollicular inflammatory infiltrate by H&E stain.
Conclusions: Topical minoxidil 5% was found to be an effective method of treatment of male androgenetic alopecia, which affects both hair density and width.
Optimal Packing Characteristics of Rolled, Continuous Stationary‐Phase Columns
Authors: Li Chenghong , Ladisch Christine M. , Yang Yiqi , Hendrickson Richard , Keim Craig , Mosier Nathan , Ladisch Michael R. 
Published: July 2002

AbstractRolled, continuous stationary phases were constructed by tightly rolling and inserting a whole textile fabric into a chromatography column. This work reports the column performance, in terms of plate height, void fraction, and resolution, of 10 cellulose‐based fabrics. The relation between fabric structural properties of yarn diameter, fabric count, fabric compressibility, and column performance are quantitated. General requirements, including reproducibility of packing, for choosing fabrics to make a good SEC column are identified. This research showed that the packed columns have an optimal mass of fabric that minimizes plate height and maximizes resolution, in a manner that is consistent with chromatography theory. Mass of material packed is then an important column parameter to consider when optimizing columns for the rapid desalting of proteins. Proteins were completely separated from salt and glucose in less than 8 min at a pressure drop less than 500 psi on the rolled, continuous stationary‐phase columns. These results, together with stability and reproducibility, suggest potential industrial applications for cellulose‐based rolled, continuous stationary‐phase columns where speed is a key parameter in the production process.
Corneal optics from videokeratographs
Authors: Hemenger Richard P. , Tomlinson Alan , Oliver Katherine 
Published: July 2002

SummaryRecent developments in measuring corneal topography make possible an improved understanding of corneal optics. It is shown, using a wavefront analysis, that optical quantities of interest follow from knowledge of sagittal depths of a cornea, and that sagittal depths are provided by or readily found from the output of commercially available instruments. The errors for normal corneas are expected to be quite small based on measurements on calibration spheres and ellipsoids. As an example the optical consequences of a peripheral asymmetry are estimated for a particular normal cornea.
Tentative anatomy of ZnS-type electroluminescence
Authors: Bringuier E. 
Published: July 2002

The paper reviews the electrical and optical mechanisms at work in sulfide-based thin-film electroluminescence display devices within the framework of general semiconductor physics. The electrical problem is twofold: (i) charge carriers are sourced at high electric field in a nominally insulating material, the carrier density increasing by almost eight orders of magnitude; (ii) the carriers are transported at high field, with an average energy largely exceeding the thermal one. (i) Carrier sourcing is best understood from direct-current-driven ZnS films, and is ascribed to partly filled deep donors transferring electrons to the conduction band by Fowler–Nordheim tunneling. The deep donors also act as carrier sinkers, and evidence for space charge is afforded by small-signal impedance analysis disclosing a markedly inductive behavior. The conduction picture obtained from dc-driven films is then used to clarify the operation of alternating-current electroluminescence structures where the sulfide is sandwiched between two blocking oxide layers. The electrostatics of the ac structure is investigated in detail including space charge and field nonuniformity, and external observables are related to internal quantities. The simple model of interfacial carrier sourcing and sinking is examined. (ii) High-field electronic transport is controlled by the electron-phonon interaction, and the modeling resorts to numerical simulations or the lucky-drift concept. At low electron energies the interaction with phonons is predominantly polar, while at optical energies it proceeds via deformation potential scattering.
In spite of the uncertainties in transport models in that range, it is likely that ∼50% of the electrons overtake 2 eV at the usual operating fields in ZnS. Light emission is associated with impurity luminescence centers embedded in the sulfide host. They are excited while current is flowing, and the ensuing relaxation is partly radiative. We describe the two ways in which an impurity may be excited electrically, namely, impact excitation (internal promotion of the center to a state of higher energy) or impact ionization (with an electron released to the host conduction band). The actual excitation mechanism depends on the position of the impurity excited level relative to the host energy bands. A calculation of the excitation yield (number of excited centers per transferred electron) is detailed in the case of impact excitation. Lastly, a phenomenological description of the various relaxation channels is given in terms of formal kinetics, and the relative importance of radiative relaxation is assessed by means of the deexcitation yield (fraction of centers decaying radiatively), which is defined in the case of the impulse response.
Ion implantation damage in Al0.6Ga0.4As/GaAs heterostructures
Authors: Turkot B. A. , Forbes D. V. , Robertson I. M. , Coleman J. J. , Rehn L. E. , Kirk M. A. , Baldo P. M. 
Published: July 2002

The damage produced at the interfaces in a sample of GaAs/Al0.6Ga0.4As/GaAs that has been subjected to ion implantation at 77 and 293 K with 1 MeV Kr+ ions has been investigated using a combination of ion channeling and transmission electron microscopy (TEM) techniques. Low temperature ion-channeling spectra obtained from samples implanted at 77 K, to an ion dose of 1014 ions cm−2, were similar to the random spectrum, indicating that the GaAs and Al0.6Ga0.4As layers had sustained a considerable degree of damage. An asymmetric signal developed in the He+ ion-channeling spectrum as the sample warmed to room temperature. The backscattering yield corresponding to the bottom interface (i.e., Al0.6Ga0.4As grown on GaAs) resembled that of the random yield, whereas that from the top interface (GaAs grown on Al0.6Ga0.4As) decreased, shifting toward the unirradiated channeled spectrum. This observation suggests that the damage produced near the top of the Al0.6Ga0.4As layer is thermally unstable. Cross-sectional TEM images reveal a greater amount of damage in the form of extended defects and amorphous regions at the bottom interface than at the top one. This difference is sufficient to account for the observed asymmetry in the channeling spectra. Increasing the ion dose to 1015 ions cm−2 produced a damage state throughout the Al0.6Ga0.4As layer that was stable at both 77 and 293 K. TEM examination revealed that at this ion dose the GaAs and Al0.6Ga0.4As layers were both amorphous. Room-temperature implantation to a dose of 1×1016 ions cm−2 was also performed. Planar defects were observed at both interfaces, although their density appeared to be greater near the bottom interface.
In addition, the bottom interface was rougher than the top. The difference in the damage states at the bottom and top interfaces can be attributed to a variation in the number of displacement cascade events as a function of depth through the Al0.6Ga0.4As layer. This variation in the number of cascades results in different amounts of ion mixing at the top and bottom interfaces.
Intramolecular energy transfer and mode-specific effects in unimolecular reactions of 1,2-difluoroethane
Authors: Raff Lionel M. 
Published: July 2002

The unimolecular decomposition reactions of 1,2-difluoroethane upon mode-specific excitation to a total internal energy of 7.5 eV are investigated using classical trajectory methods and a previously formulated empirical potential-energy surface. The decomposition channels for 1,2-difluoroethane are, in order of importance, four-center HF elimination, C–C bond rupture, and hydrogen–atom dissociation. This order is found to be independent of the particular vibrational mode excited. Neither fluorine–atom nor F2 elimination reactions are ever observed even though these dissociation channels are energetically open. For four-center HF elimination, the average fraction of the total energy partitioned into internal HF motion varies between 0.115–0.181 depending upon the particular vibrational mode initially excited. The internal energy of the fluoroethylene product lies in the range 0.716–0.776. Comparison of the present results with those previously obtained for a random distribution of the initial 1,2-difluoroethane internal energy [J. Phys. Chem. 92, 5111 (1988)], shows that numerous mode-specific effects are present in these reactions in spite of the fact that intramolecular energy transfer rates for this system are 5.88–25.5 times faster than any of the unimolecular reaction rates. Mode-specific excitation always leads to a total decomposition rate significantly larger than that obtained for a random distribution of the internal energy. Excitation of different 1,2-difluoroethane vibrational modes is found to produce as much as a 51% change in the total decomposition rate. Mode-specific effects are also seen in the product energy partitioning. The rate coefficients for decomposition into the various channels are very sensitive to the particular mode excited. A comparison of the calculated mode-specific effects with the previously determined mode-to-mode energy transfer rate coefficients [J. Chem. Phys. 89, 5680 (1988)] shows that, to some extent, the presence of mode-specific chemistry is correlated with the magnitude of the energy transfer rate. However, the particular pathways for energy flow seem to be more important than the magnitude of the rate coefficients. It is suggested that the propensity for the energy to remain
isolated in small subset of modes, such as the CH2F deformation modes or the rocking modes, is primarily responsible for the observation of mode-specific chemistry. The results clearly demonstrate that an intramolecular energy transfer rate that is fast relative to the unimolecular reaction rate is not a sufficient condition to ensure the absence of mode-specific chemical
effects.
Interdimensional degeneracy and symmetry breaking in D-dimensional H+2
Authors: Frantz D. D. , Herschbach D. R. 
Published: July 2002

An interdimensional degeneracy linking the orbital angular momentum projection ‖m‖ and spatial dimension D gives D-dimensional eigenstates for H+2 by simple correspondence with suitably scaled D=3 excited states. The wave equation for fixed nuclei is separable in D-dimensional spheroidal coordinates, giving generalized two-center differential equations with parametric dependence on the internuclear distance R. By incorporating‖m‖ into D, the resulting eigenstates can be classified by the two dimension-independent ‘‘radial’’ quantum numbers denoted in united atom notation by k and l−‖m‖, corresponding, respectively, to the number of ellipsoidal and hyperboloidal nodal surfaces in the wave function. The two eigenparameters, the energy ED(R), and a separation constant AD(R) related to the total orbital angular momentum and the Runge–Lenz vector, have been determined numerically for the ground state and several low lying excited states for selected dimensions from D=2 to D=100.
The system simplifies greatly in the limit D→∞, where the electronic structure reduces to a classical electrostatic form with the electrons in a fixed geometrical configuration relative to the nuclei, akin to the traditional Lewis electron-dot structure. For a given R, the energy E∞ reduces to the minimum of an effective potential surface and the separation constant A∞ reduces to a simple function of the energy. The surfaces are separable in spheroidal coordinates resulting in analytical expressions for the energy in terms of the coordinates. The surfaces exhibit a characteristic symmetry breaking as functions of R, changing from a single minimum surface in the united atom limit (R→0) to a double minimum surface in the separated atom limit (R→∞). Effects of this symmetry breaking are found at finite D as well. Analysis of excited state D-dimensional energies reveals that bonding in H+2 is determined primarily by k, contrary to the standard scheme of bonding and antibonding molecular orbitals, which in the case of H+2 correspond to even and odd l−‖m‖, respectively. When the D-dimensional energies are examined as functions of 1/D, the resulting curves resemble typical perturbation diagrams with 1/D as the perturbation parameter.
Kinetics of intramolecular carbon atom exchange in ketene
Authors: Lovejoy Edward R. , Kim Sang Kyu , Alvarez Ramón A. , Moore C. Bradley 
Published: July 2002

Intramolecular carbon atom exchange in highly vibrationally excited ketene was studied by monitoring the carbon monoxide fragments (12CO and 13CO ) from the photodissociation of 12CH213CO and 13CH212CO. Two experimental techniques were employed. In one set of experiments the IR transient absorptions of 12CO and 13CO were measured following pulsed excimer excitation of ketene 13C isotopomers, giving carbon atom exchange yields at 351 and 308 nm in a low pressure gas cell. In the other set of experiments, jet-cooled ketene 13C isotopomers were excited with tunable near-UV radiation, and the CO products were detected by monitoring their VUV laser-induced fluorescence. Carbon atom exchange yields were measured for energies extending from below the triplet decomposition threshold (CH2CO→CH2(X 3B1)+CO(X 1Σ+)) to about 4000 cm−1 above the singlet threshold (CH2CO→CH2(a 1A1)+CO(X 1Σ+)).
The exchange yields range from 4 to 19%, and the energy dependence of the yield exhibits pronounced structure, with maxima at the triplet and singlet decomposition thresholds. Kinetic measurements of the appearance of the CO products were also performed. The time constant for the appearance of the exchanged CO (e.g., 13CO from 13CH212CO ) is significantly longer than that for the direct CO fragment (e.g., 12CO from 13CH212CO ). All the experimental observations are consistent with a simple reaction mechanism involving ketene isomerization, 13CH212CO⇄12CH213CO, and dissociation, 13CH212CO→13CH2+12CO and 12CH213CO→12CH2+13CO. The isomerization rate constant was determined by analyzing the CO kinetics and the carbon atom exchange yields in terms of the simple isomerization mechanism. A fit of the energy dependence of the isomerization rate constant to the results of tunneling-corrected Rice–Ramsberger–Kassel–Marcus (RRKM) calculations gave the threshold (28360±60 cm−1 ) for the isomerization process.
Excitation of CO2 by energy transfer from highly vibrationally excited benzene derivatives
Authors: Toselli Beatriz M. , Barker John R. 
Published: July 2002

The time-resolved infrared fluorescence technique has been used to study V–V and V–T/R energy transfer to carbon dioxide from highly excited benzene, benzene-d6, toluene, and toluene-d8. The highly vibrationally excited aromatics in the electronic ground state are obtained by radiationless transitions after pumping with a KrF laser at 248 nm to the S1 excited electronic level. The V–V energy transfer from the excited parent to the asymmetric stretch mode of CO2 was measured by observing the characteristic emission of CO*2 near 4.3 μm. From these measurements, the probability per collision of formation of CO*2 was determined as a function of the internal energy in the excited aromatic. In all cases investigated, this probability is ≤0.1% at the initial excitation energy of 40 000 cm−1 and it is approximately directly proportional to the vibrational energy of the excited aromatic. The total concentration of CO*2 produced as a result of the many collisions needed to totally deactivate the excited aromatic amounted to &gt;5% of the initial concentration of the excited aromatic and the quantitative values obtained are in excellent agreement with other work.
A simple dipole–dipole interaction model is shown to explain the observed magnitude of V–V energy transfer and it is used to predict the amount of energy transferred to the bending mode of CO2. A key feature of this model is that the states of the highly vibrationally excited polyatomic are assumed to be broadened by rapid intramolecular vibrational redistribution of energy. In addition to the V–V energy-transfer measurements, the average energy lost per collision by the excited aromatic was determined as a function of the vibrational energy of the aromatic, and the rate constants were determined for CO*2 deactivation by the nondeuterated species. For the deuterated species, the results implicated a contribution from resonant V–V transfer between the C–D stretch modes and the asymmetric stretch mode of CO2. The overall results for the CO2 collider gas indicate that V–V energy transfer contributes a relatively small portion of the total energy transfer, and that portion can be described with the dipole–dipole interactions model.