Impact of Leadership Styles on Job Satisfaction among Teachers in Secondary Schools in Monduli District

The purpose of this study was to explore the impact of leadership styles on job satisfaction among teachers in selected secondary schools in Monduli district. The study hypotheses were that H1 there is no statistically significant correlation between transformational leadership style and job satisfaction among teachers in selected secondary schools in Monduli district, H2 there is no statistically significant correlation between transactional leadership style and job satisfaction among teachers in selected secondary schools in Monduli district and H3 there is no statistically significant correlation between laissez-faire leadership style and job satisfaction among teachers in selected secondary schools in Monduli district.  The study employed a descriptive survey design. A sample size of one hundred twenty-nine respondents was randomly chosen from four secondary schools in Monduli namely; Manyara, Lowassa, Engutoto, and Irkisongo district secondary schools. A self-administered questionnaire was used to collect information from respondents. The collected data were analyzed by Statistical Package for Social Scientists (SPSS) using, Independent t-test and Fisher's Analysis of Variance (ANOVA) to determine whether demographic variables varied with students' academic performance. Karl Pearson's Linear Correlation Coefficient was undertaken to determine the relationship between leadership styles and teachers' Job satisfaction.  The study results indicated that hypotheses H1 and H3 were supported by the study findings. However, the study findings revealed that H3 was not supported by the study findings. The study concluded that transformational and laissez-faire leadership styles had a direct influence on teachers' job satisfaction. Therefore, school administrators in the Monduli district should use transformational and laissez-faire leadership styles in their day-to-day administration. The study findings led the researcher to recommend that, the school administration should focus on the use of transformational and laissez-faire leadership styles since they had a direct significant influence on teacher's job satisfaction. For future research focus should be on obtaining a larger and more representative sample, conducting the same study in other schools from another district for comparison purposes, and replicating the study using a qualitative approach.&nbsp

Theory of the optical properties of III-V semiconductor quantum wells

The aim of this project is to investigate the electronic and optical properties of III-V semiconductor quantum wells, specifically those based on the GaAs-AlGaAs system. Both the linear and non-linear optical properties of these systems are considered. A theoretical model for the refractive index in GaAs-AlGaAs quantum well structures for optical frequencies close in energy to the fundamental band gap has been constructed, and is based on knowledge of the electronic band structure. This model includes the valley states, and also allows for inclusion of the electronic states at the X and L points. The ground state and excited state excitons have also been explicitly included within the theoretical model. The exciton model which is employed in this thesis takes into account the Coulomb coupling between different exciton states. In addition, the effects of band filling and screening have both been incorporated, allowing the intensity-dependent index of refraction to be obtained. Calculations are presented for a range of material compositions and quantum well structures, including both single and double quantum wells. The results obtained for the index of refraction are therefore more complete and accurate than any previous published calculations. It is expected that the results presented here can be used directly in the design of refractive-based optoelectronic devices

Effect of salt on germination of samphire species

Nine Halosarcia plant species from Lake Carey, Western Australia, were tested to determine the effect of salt on seed germination. These species were Halosarcia \u27Angel Fish Island\u27 (B. Davey 4) Halosarcia calyptrata Paul G. Wilson, Halosarcia halocnemoides (Nees) Paul G. Wilson, Halosarcia peltata Paul G. Wilson, Halosarcia pergranulata (J. M. Black) Paul G. Wilson, Halosarcia undulata Paul G. Wilson. All species were subjected to salt concentrations of 0, 10, 20 and 30 g/l NaCl both in the laboratory in Petri dishes and under outdoor conditions, wither buried or on the surface of soil from the lake margin. The nine species were also tested for their ability to recover, the seeds were germinated in fresh water. For the majority of species, increased NaCl concentrations resulted in decreased germination percentages both in the laboratory and outdoors. In contrast, H. halocnemoides showed a slight increase in germination percentages at higher NaCl concentrations. In laboratory trials, the greatest reduction in germination percentage was 81% for H. \u27Angel Fish Island\u27; the average reduction was 37% across all species. In outdoor experiments, germination only reached a maximum of 25% which could have been due to lack of moisture, scarification of seeds, or temperature. Averaged across all the species, there was an increase of 58% in germination of the remaining seeds once salt was removed by flushing with fresh water

Electronic States in Diffused Quantum Wells

In the present study we calculate the energy values and the spatial distributions of the bound electronic states in some diffused quantum wells. The calculations are performed within the virtual crystal approximation, $sp^3 s^*$ spin dependent empirical tight-binding model and the surface Green function matching method. A good agreement is found between our results and experimental data obtained for AlGaAs/GaAs quantum wells with thermally induced changes in the profile at the interfaces. Our calculations show that for diffusion lengths $L_{D}=20\div100$ {\AA} the transition (C3-HH3) is not sensitive to the diffusion length, but the transitions (C1-HH1), (C1-LH1), (C2-HH2) and (C2-LH2) display large "blue shifts" as L_{D} increases. For diffusion lengths $L_{D}=0\div20$ {\AA} the transitions (C1-HH1) and (C1-LH1) are less sensitive to the L_{D} changes than the (C3-HH3) transition. The observed dependence is explained in terms of the bound states spatial distributions.Comment: ReVTeX file, 7pp., no macros, 4 figures available on the reques

Woodland birds and rural towns: artificial clutch survival in fragmented Box-Ironbark forests

Woodland birds are declining throughout the agricultural landscapes of south-eastern Australia, but the specific mechanisms driving these declines remain unclear. Reproductive failure via clutch depredation could conceivably contribute to these declines. Although site-scale habitat may influence the risk of clutch failure, larger-scale influences, such as whether a landscape contains a rural town or not (‘landscape type’), may also play a role. This study monitored artificial open-cup nests deployed in three pairs of the two landscape types and: 1) indexed clutch survival and predator assemblage; and 2) determined if clutch survival was influenced by landscape type and/or local habitat characteristics. High levels of clutch depredation were observed in both landscape types and for all landscapes, with no evidence to suggest that landscape type or habitat characteristics influenced clutch survival or the time-to-first-predator visit. Predator assemblage also was consistent between landscape types. Generalist avian predators were the most common egg predators. Such egg predators may be ubiquitous throughout the fragmented Box-Ironbark woodlands of south-eastern Australia

Electron and hole states in quantum-dot quantum wells within a spherical 8-band model

In order to study heterostructures composed both of materials with strongly different parameters and of materials with narrow band gaps, we have developed an approach, which combines the spherical 8-band effective-mass Hamiltonian and the Burt's envelope function representation. Using this method, electron and hole states are calculated in CdS/HgS/CdS/H_2O and CdTe/HgTe/CdTe/H_2O quantum-dot quantum-well heterostructures. Radial components of the wave functions of the lowest S and P electron and hole states in typical quantum-dot quantum wells (QDQWs) are presented as a function of radius. The 6-band-hole components of the radial wave functions of an electron in the 8-band model have amplitudes comparable with the amplitude of the corresponding 2-band-electron component. This is a consequence of the coupling between the conduction and valence bands, which gives a strong nonparabolicity of the conduction band. At the same time, the 2-band-electron component of the radial wave functions of a hole in the 8-band model is small compared with the amplitudes of the corresponding 6-band-hole components. It is shown that in the CdS/HgS/CdS/H_2O QDQW holes in the lowest states are strongly localized in the well region (HgS). On the contrary, electrons in this QDQW and both electron and holes in the CdTe/HgTe/CdTe/H_2O QDQW are distributed through the entire dot. The importance of the developed theory for QDQWs is proven by the fact that in contrast to our rigorous 8-band model, there appear spurious states within the commonly used symmetrized 8-band model.Comment: 15 pages, 5 figures, E-mail addresses: [email protected], [email protected]

General boundary conditions for the envelope function in multiband k.p model

We have derived general boundary conditions (BC) for the multiband envelope functions (which do not contain spurious solutions) in semiconductor heterostructures with abrupt heterointerfaces. These BC require the conservation of the probability flux density normal to the interface and guarantee that the multiband Hamiltonian be self--adjoint. The BC are energy independent and are characteristic properties of the interface. Calculations have been performed of the effect of the general BC on the electron energy levels in a potential well with infinite potential barriers using a coupled two band model. The connection with other approaches to determining BC for the envelope function and to the spurious solution problem in the multiband k.p model are discussed.Comment: 15 pages, 2 figures; to be published in Phys. Rev. B 65, March 15 issue 200

Development of an eight-band theory for quantum-dot heterostructures

We derive a nonsymmetrized 8-band effective-mass Hamiltonian for quantum-dot heterostructures (QDHs) in Burt's envelope-function representation. The 8x8 radial Hamiltonian and the boundary conditions for the Schroedinger equation are obtained for spherical QDHs. Boundary conditions for symmetrized and nonsymmetrized radial Hamiltonians are compared with each other and with connection rules that are commonly used to match the wave functions found from the bulk kp Hamiltonians of two adjacent materials. Electron and hole energy spectra in three spherical QDHs: HgS/CdS, InAs/GaAs, and GaAs/AlAs are calculated as a function of the quantum dot radius within the approximate symmetrized and exact nonsymmetrized 8x8 models. The parameters of dissymmetry are shown to influence the energy levels and the wave functions of an electron and a hole and, consequently, the energies of both intraband and interband transitions.Comment: 36 pages, 10 figures, E-mail addresses: [email protected], [email protected]