We study stationary scattering theory for finitely many sphere interactions formally given by the... more We study stationary scattering theory for finitely many sphere interactions formally given by the Hamiltonian H=−Δ+∑j=1Nαjδ(|x|−Rj) and its generalizations to the case of interactions of the second type and interactions with nonseparated boundary conditions. In a previous publication [J. Math. Phys. 29, 660–664 (1988)], it was shown that the self-adjoint Hamiltonian H{αl},{R} corresponding to H may be defined as a limit in norm resolvent convergence of a family Hε of local scaled short-range Hamiltonians. In this paper we also study scattering theory corresponding to Hε and show that the scattering quantities associated with Hε converge to those of H{αl},{R} as ε→0.
In line with the functional, organizational and political approach to regionalization of higher e... more In line with the functional, organizational and political approach to regionalization of higher education which is discussed in the first chapter of this book, quality assurance is one of the core functional element of higher education regionalization process that this chapter will be discussing.
Approaches to teaching science are undergoing a mutation and new variants such as the Culturo-Tec... more Approaches to teaching science are undergoing a mutation and new variants such as the Culturo-Techno-Contextual Approach (CTCA) have emerged and are proving to be more potent than the older variants. This study explored the efficacy of CTCA in reducing learning anxiety and promoting meaningful learning of chemistry among secondary school students by comparing the performance of the two experimental groups with that of the control group. The study employed an explanatory sequential design. The quantitative phase was quasi-experimental, while the qualitative phase was an in-depth interview. A total of 141 senior secondary II students (the equivalent of grade 11) from three purposively selected schools in Lagos State education district V were sampled. The Electrochemistry Achievement Test and revised Science Anxiety Scale which had reliability coefficients of 0.78 and 0.95, respectively, were the instruments used to collect quantitative data, while the students’ perception about CTCA i...
This study is concerned with the persistent underperformance of secondary school students in Nige... more This study is concerned with the persistent underperformance of secondary school students in Nigeria in physics. The study was conducted in two phases. Phase one was a survey of difficult concepts in physics, while phase two explored the potency of culturo-techno-contextual approach (CTCA) in breaking the barriers to meaningful learning of refractive indices, which ranked the most difficult concept in phase one of the study. A total of 1621 SS3 students from Nigeria and Ghana participated in the survey phase. The second phase employed a mixed-methods approach (quasi-experimental and interviews) with a total of 205 SS1 students. The control group was taught with the lecture method and had 96 students (54 males; 42 females), while the experimental group, taught with CTCA, had 109 students (65 females; 44 males). Both groups had a pretest and posttest using the achievement test in refractive indices; treatment lasted four weeks. Data gathered in the survey were analyzed using mean rank...
A perturbation theory of embedded eigenvalues is constructed for a class of models with a contact... more A perturbation theory of embedded eigenvalues is constructed for a class of models with a contact interaction which are inspired by heavy-quarkonia mesonic decays.
PurposeStudents' career choices and programmes of study are perceived to influence student un... more PurposeStudents' career choices and programmes of study are perceived to influence student understanding of many courses. Yet, research attention is limited on entrepreneurship education that is a panacea for unemployment. Thus, this paper aims to assess the influence of students' career interests on students' comprehension of the entrepreneurship curriculum from a developing economy perspective.Design/methodology/approachThe study adopts a mixed-method approach and explanatory sequential design is used to collect the data from 575 student studying entrepreneurship course in Ghana.FindingsThe results show that there is no statistically significant relationship between students' career interests and students' comprehension levels in concepts taught in the entrepreneurship curriculum but a statistically significant relationship between students' programme of study and students' comprehension levels in concepts taught in the entrepreneurship curriculum in Gh...
There have been few studies on students’ difficulty in the computer studies curriculum of African... more There have been few studies on students’ difficulty in the computer studies curriculum of African senior secondary schools. This study attempts to fill this gap by investigating the concepts students find difficult in the Ghanaian and Nigerian computer science curriculum and the influence of students’ career interests on these perceived difficult concepts. The study is important to the extent that our understanding of “where the shirt tights” regarding topics difficulty will guide teachers, students, secondary schools’ managers, and governments in applying applicable remediating measures. The study sought to establish (a) the concepts that students perceive to be difficult in the computer studies curriculum in Ghanaian and Nigerian schools and (b) if there is a statistically significant relationship between students’ career interests and perceived concept difficulty in computer studies. Anchored on cognitive constructivism theory of Piaget, a quantitative method was employed with th...
It was recently reported that a continuous electric current is a powerful control parameter to tr... more It was recently reported that a continuous electric current is a powerful control parameter to trigger changes in the electronic structure and metal-insulator transitions (MITs) in Ca 2 RuO 4. However, the spatial evolution of the MIT and the implications of the unavoidable Joule heating have not been clarified yet, often hindered by the difficulty to asses the local sample temperature. In this work, we perform infrared thermal imaging on single-crystal Ca 2 RuO 4 while controlling the MIT by electric current. The change in emissivity at the phase transition allows us to monitor the gradual formation and expansion of metallic phase upon increasing current. Our local temperature measurements indicate that, within our experimental resolution, the MIT always occurs at the same local transition temperatures, irrespectively if driven by temperature or by current. Our results highlight the importance of local heating, phase coexistence, and microscale inhomogeneity when studying strongly correlated materials under the flow of electric current.
Journal of Physics A: Mathematical and General, 1987
ABSTRACT The authors discuss exactly solvable Schrodinger Hamiltonians corresponding to a surface... more ABSTRACT The authors discuss exactly solvable Schrodinger Hamiltonians corresponding to a surface delta interaction supported by a sphere and various generalisations thereof. First they treat the pure delta sphere model; self-adjointness of the Hamiltonian, spectral properties, stationary scattering theory, approximation by scaled short-range Hamiltonians. Next they extend the model by adding a point interaction at the centre of the sphere or, alternatively, a Coulomb interaction. Finally the whole analysis is extended to the case of a delta ' sphere interaction, first taken alone, then superimposed on a point interaction or a Coulomb potential.
The main purpose of this study was to identify difficulties encountered in understanding chemistr... more The main purpose of this study was to identify difficulties encountered in understanding chemistry in the universities in Burundi. The study further examined the influence of gender and students' previous background in chemistry on their understanding of chemistry. The study used a sample of N = 817 students from 2 public universities and 2 private universities in Burundi. A survey was conducted to characterize the difficult concepts encountered by students in general chemistry. To achieve the study's objective, we used the mean analysis, frequency, percentage and Pearson correlation at a significance level of α = 0.05. The results showed that among 23 concepts investigated, pH and octet rule are perceived as the most difficult concepts, with a percentage of 50.4% and 51.0%, respectively. The concept of acid was perceived as the least difficult, with a percentage of 17.3%. These findings were significantly linked to gender (p= .000) and concept difficulty, previous background (p= .000) and concept difficulty, and Lack of didactic material in the laboratory (p=.000) and concept difficulty. Appropriate remediating measures have been proferred to enhance students' understanding of chemistry. 304 François Nitereka et al.
As an extension of Gabor signal processing, the covariant Weyl-Heisenberg integral quantization i... more As an extension of Gabor signal processing, the covariant Weyl-Heisenberg integral quantization is implemented to transform functions on the eight-dimensional phase space x,k into Hilbertian operators. The x=xμ values are space-time variables, and the k=kμ values are their conjugate frequency-wave vector variables. The procedure is first applied to the variables x,k and produces essentially canonically conjugate self-adjoint operators. It is next applied to the metric field gμν(x) of general relativity and yields regularized semi-classical phase space portraits gˇμν(x). The latter give rise to modified tensor energy density. Examples are given with the uniformly accelerated reference system and the Schwarzschild metric. Interesting probabilistic aspects are discussed.
We study stationary scattering theory for finitely many sphere interactions formally given by the... more We study stationary scattering theory for finitely many sphere interactions formally given by the Hamiltonian H=−Δ+∑j=1Nαjδ(|x|−Rj) and its generalizations to the case of interactions of the second type and interactions with nonseparated boundary conditions. In a previous publication [J. Math. Phys. 29, 660–664 (1988)], it was shown that the self-adjoint Hamiltonian H{αl},{R} corresponding to H may be defined as a limit in norm resolvent convergence of a family Hε of local scaled short-range Hamiltonians. In this paper we also study scattering theory corresponding to Hε and show that the scattering quantities associated with Hε converge to those of H{αl},{R} as ε→0.
In line with the functional, organizational and political approach to regionalization of higher e... more In line with the functional, organizational and political approach to regionalization of higher education which is discussed in the first chapter of this book, quality assurance is one of the core functional element of higher education regionalization process that this chapter will be discussing.
Approaches to teaching science are undergoing a mutation and new variants such as the Culturo-Tec... more Approaches to teaching science are undergoing a mutation and new variants such as the Culturo-Techno-Contextual Approach (CTCA) have emerged and are proving to be more potent than the older variants. This study explored the efficacy of CTCA in reducing learning anxiety and promoting meaningful learning of chemistry among secondary school students by comparing the performance of the two experimental groups with that of the control group. The study employed an explanatory sequential design. The quantitative phase was quasi-experimental, while the qualitative phase was an in-depth interview. A total of 141 senior secondary II students (the equivalent of grade 11) from three purposively selected schools in Lagos State education district V were sampled. The Electrochemistry Achievement Test and revised Science Anxiety Scale which had reliability coefficients of 0.78 and 0.95, respectively, were the instruments used to collect quantitative data, while the students’ perception about CTCA i...
This study is concerned with the persistent underperformance of secondary school students in Nige... more This study is concerned with the persistent underperformance of secondary school students in Nigeria in physics. The study was conducted in two phases. Phase one was a survey of difficult concepts in physics, while phase two explored the potency of culturo-techno-contextual approach (CTCA) in breaking the barriers to meaningful learning of refractive indices, which ranked the most difficult concept in phase one of the study. A total of 1621 SS3 students from Nigeria and Ghana participated in the survey phase. The second phase employed a mixed-methods approach (quasi-experimental and interviews) with a total of 205 SS1 students. The control group was taught with the lecture method and had 96 students (54 males; 42 females), while the experimental group, taught with CTCA, had 109 students (65 females; 44 males). Both groups had a pretest and posttest using the achievement test in refractive indices; treatment lasted four weeks. Data gathered in the survey were analyzed using mean rank...
A perturbation theory of embedded eigenvalues is constructed for a class of models with a contact... more A perturbation theory of embedded eigenvalues is constructed for a class of models with a contact interaction which are inspired by heavy-quarkonia mesonic decays.
PurposeStudents' career choices and programmes of study are perceived to influence student un... more PurposeStudents' career choices and programmes of study are perceived to influence student understanding of many courses. Yet, research attention is limited on entrepreneurship education that is a panacea for unemployment. Thus, this paper aims to assess the influence of students' career interests on students' comprehension of the entrepreneurship curriculum from a developing economy perspective.Design/methodology/approachThe study adopts a mixed-method approach and explanatory sequential design is used to collect the data from 575 student studying entrepreneurship course in Ghana.FindingsThe results show that there is no statistically significant relationship between students' career interests and students' comprehension levels in concepts taught in the entrepreneurship curriculum but a statistically significant relationship between students' programme of study and students' comprehension levels in concepts taught in the entrepreneurship curriculum in Gh...
There have been few studies on students’ difficulty in the computer studies curriculum of African... more There have been few studies on students’ difficulty in the computer studies curriculum of African senior secondary schools. This study attempts to fill this gap by investigating the concepts students find difficult in the Ghanaian and Nigerian computer science curriculum and the influence of students’ career interests on these perceived difficult concepts. The study is important to the extent that our understanding of “where the shirt tights” regarding topics difficulty will guide teachers, students, secondary schools’ managers, and governments in applying applicable remediating measures. The study sought to establish (a) the concepts that students perceive to be difficult in the computer studies curriculum in Ghanaian and Nigerian schools and (b) if there is a statistically significant relationship between students’ career interests and perceived concept difficulty in computer studies. Anchored on cognitive constructivism theory of Piaget, a quantitative method was employed with th...
It was recently reported that a continuous electric current is a powerful control parameter to tr... more It was recently reported that a continuous electric current is a powerful control parameter to trigger changes in the electronic structure and metal-insulator transitions (MITs) in Ca 2 RuO 4. However, the spatial evolution of the MIT and the implications of the unavoidable Joule heating have not been clarified yet, often hindered by the difficulty to asses the local sample temperature. In this work, we perform infrared thermal imaging on single-crystal Ca 2 RuO 4 while controlling the MIT by electric current. The change in emissivity at the phase transition allows us to monitor the gradual formation and expansion of metallic phase upon increasing current. Our local temperature measurements indicate that, within our experimental resolution, the MIT always occurs at the same local transition temperatures, irrespectively if driven by temperature or by current. Our results highlight the importance of local heating, phase coexistence, and microscale inhomogeneity when studying strongly correlated materials under the flow of electric current.
Journal of Physics A: Mathematical and General, 1987
ABSTRACT The authors discuss exactly solvable Schrodinger Hamiltonians corresponding to a surface... more ABSTRACT The authors discuss exactly solvable Schrodinger Hamiltonians corresponding to a surface delta interaction supported by a sphere and various generalisations thereof. First they treat the pure delta sphere model; self-adjointness of the Hamiltonian, spectral properties, stationary scattering theory, approximation by scaled short-range Hamiltonians. Next they extend the model by adding a point interaction at the centre of the sphere or, alternatively, a Coulomb interaction. Finally the whole analysis is extended to the case of a delta ' sphere interaction, first taken alone, then superimposed on a point interaction or a Coulomb potential.
The main purpose of this study was to identify difficulties encountered in understanding chemistr... more The main purpose of this study was to identify difficulties encountered in understanding chemistry in the universities in Burundi. The study further examined the influence of gender and students' previous background in chemistry on their understanding of chemistry. The study used a sample of N = 817 students from 2 public universities and 2 private universities in Burundi. A survey was conducted to characterize the difficult concepts encountered by students in general chemistry. To achieve the study's objective, we used the mean analysis, frequency, percentage and Pearson correlation at a significance level of α = 0.05. The results showed that among 23 concepts investigated, pH and octet rule are perceived as the most difficult concepts, with a percentage of 50.4% and 51.0%, respectively. The concept of acid was perceived as the least difficult, with a percentage of 17.3%. These findings were significantly linked to gender (p= .000) and concept difficulty, previous background (p= .000) and concept difficulty, and Lack of didactic material in the laboratory (p=.000) and concept difficulty. Appropriate remediating measures have been proferred to enhance students' understanding of chemistry. 304 François Nitereka et al.
As an extension of Gabor signal processing, the covariant Weyl-Heisenberg integral quantization i... more As an extension of Gabor signal processing, the covariant Weyl-Heisenberg integral quantization is implemented to transform functions on the eight-dimensional phase space x,k into Hilbertian operators. The x=xμ values are space-time variables, and the k=kμ values are their conjugate frequency-wave vector variables. The procedure is first applied to the variables x,k and produces essentially canonically conjugate self-adjoint operators. It is next applied to the metric field gμν(x) of general relativity and yields regularized semi-classical phase space portraits gˇμν(x). The latter give rise to modified tensor energy density. Examples are given with the uniformly accelerated reference system and the Schwarzschild metric. Interesting probabilistic aspects are discussed.
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Papers by Juma Shabani