Environmental Perspective of Urban Agriculture in Debre Markos Town, Amhara Regional State, Ethiopia

Urban agriculture plays great role in environmental benefits to urban farmers in particular and urban dwellers at large to grasp the significance of the sector towards urban environments. It also contributes challenges to the environment unless urban farmers take care of farming practices. So, the study focused on identifying the major types of UA in Debre Markos Town, identifying stakeholders involved in urban agriculture, challenges of urban agriculture to the environment and environmental benefits of urban agriculture. Basically the study employed a descriptive research type. Both qualitative and quantitative approaches were used. And 152 samples were systematically selected from individual farmers, micro and small enterprise under urban agriculture, and investors. Eight officials were selected through purposive sampling from relevant governmental organizations. Empirical data was collected through structured questionnaire, interview guiding questions, focus group discussion, and on spot observation. The data gathered via the aforementioned techniques were analyzed and the findings were presented using tables, charts, and plates. Accordingly, the findings revealed that animal husbandry is the most common urban agricultural activity in Debre Markos Town following green biodiversity enrichment. In addition, though the multi-stakeholders are participating in urban agriculture, their environmental concern was very low. It is evident that 55.9% of challenges of urban agriculture to the environment are waste dumping, soil loss and loss of biodiversity due to ignorance of environmental attention while farming in the town. From the study, it is concluded that composting of both municipal and household waste for urban agriculture is a neglected activity which would have been used for augmenting of soil fertility instead of polluting the urban environment. It also recommends that awareness creation; spur on institutional support with special attention to the environment and rendering technical extension service as it has been case for rural areas to solve negative environmental outlooks and practices of urban farmers should be strengthened. Key words: urban agriculture, urban farmer, environmental challenge, environmental benefit, Ethiopi

Electronic properties of single-walled carbon nanotubes inside cyclic supermolecules

Possible ways for manipulating carbon nanotubes (CNTs) with cyclic supermolecules are studied using density functional theory. Electronic structure calculations with structure optimizations have been performed for the (4,4) and (8,0) single-walled carbon nanotubes (SWNTs) complexed with crown ethers as well as for the (4,0) SWNT with beta-cyclodextrin. A slight polarization of charge in both the nanotube and the supermolecule is observed upon rotaxane complexation, but the interaction is mainly repulsive, and the systems stay 2.8-3.5 A apart. The supermolecule does not affect the electronic band structure of the nanotube significantly within such a configuration. The situation differs noticeably for chemically cross-linked SWNTs and crown ethers, where a peak arises at the Fermi energy in the density of states. As a result, the band gap of semiconducting CNT(8,0) (0.5 eV) vanishes, and a new conduction channel opens for the metallic CNT(4,4)

Determinants of job satisfaction for salaried and self-employed professionals in Finland

This article contributes to our knowledge of the determinants of job satisfaction by analysing the effects of employment status (self-employed or salaried employee) and work characteristics (autonomy, variety, task identity, task significance and feedback) on job satisfaction in a sample of 2327 Finnish professionals. The results of the analysis show that although the self-employed professionals are significantly more satisfied with their jobs than their salaried counterparts in Finland, employment status as such does not explain job satisfaction when the five work characteristics are added to the structural model. Furthermore, the analysis finds that task significance, variety and autonomy have similar effects on the level of job satisfaction among both employees and self-employed individuals, while feedback has a weaker effect when the individual is self-employed and task identity does not affect job satisfaction in either group. Overall, the study points to the need to develop jobs that are high in autonomy, variety and task significance for professionals in order to enhance job satisfaction

Electronic shell and supershell structure in graphene flakes

We use a simple tight-binding (TB) model to study electronic properties of free graphene flakes. Valence electrons of triangular graphene flakes show a shell and supershell structure which follows an analytical expression derived from the solution of the wave equation for triangular cavity. However, the solution has different selection rules for triangles with armchair and zigzag edges, and roughly 40000 atoms are needed to see clearly the first supershell oscillation. In the case of spherical flakes, the edge states of the zigzag regions dominate the shell structure which is thus sensitive to the flake diameter and center. A potential well that is made with external gates cannot have true bound states in graphene due to the zero energy band gap. However, it can cause strong resonances in the conduction band.Comment: Presented in the ISSPIC-14 conference, Valladolid, September 200

Josephson effect in graphene bilayers with adjustable relative displacement

The Josephson current is investigated in a superconducting graphene bilayer where the pristine graphene sheets can make in-plane or out-of-plane displacements with respect to each other. The superconductivity can be of intrinsic nature, or due to a proximity effect. The results demonstrate that the supercurrent responds qualitatively differently to relative displacement if the superconductivity is due to either intralayer or interlayer spin-singlet electron-electron pairing, thus providing a tool to distinguish between the two mechanisms. Specifically, both the AA and AB stacking orders are studied with antiferromagnetic spin alignment. For the AA stacking order with intralayer and on-site pairing no current reversal is found. In contrast, the supercurrent may switch its direction as a function of the in-plane displacement and out-of-plane interlayer coupling for the cases of AA ordering with interlayer pairing and AB ordering with either intralayer or interlayer pairing. In addition to sign reversal, the Josephson signal displays many characteristic fingerprints which derive directly from the pairing mechanism. Thus, measurements of the Josephson current as a function of the graphene bilayer displacement open up means for achieving a deeper insight of the superconducting pairing mechanism

Palveluorganisaation tunnettuus ja ulkoinen imago : case: JobCafé

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