Dipole moment effects in photodetachment from cluster anions

In this dissertation results from experimental studies on the effect of the dipole moment on photodetachment from solvated iodide anion are presented. The major advantage of using solvated atomic iodide anions: I−·(Y)n: Y = solvent molecule, n=1 to 3)) to study this effect is that in the ground state, the excess electron is mainly localized on the iodine atom for which photodetachment behavior is well understood. The effect of the electric dipole moment of the resultant neutral cluster on the outgoing electron is studied by comparing the photoelectron angular distributions: PADs) for I−·(Y)n and I− photodetachment. The results show strong dipole moment effects in the vicinity of direct detachment thresholds due to the presence of dipole-supported states, [I: 2P3/2)·(Y)n] − and I(2P1/2)·(Y) n]−. Vertical photoexcitation near the threshold for production of the excited neutral cluster I(2P1/2) ·(Y)n shows evidence of strong mixing of the direct: I−·(Y)n→ I: 2P3/2) +: Y)n + e−) channel and a dipole-supported state, [I(2P1/2)·(Y) n]− in the PADs. It is shown that increasing the dipole moment of I(2P1/2)·(Y)n for n=1 increases this channel coupling while for n \u3e 1, the situation is more complex due to competing dynamics. Results are also presented for photodetachment from a stable dipole-bound CH3CN− anion in the vicinity of a well-known electron scattering resonance. Despite the presence of this π *CN it appears to have very little effect on the photoelectron angular distributions. This initially surprising behavior is attributed to the relatively low contribution of higher partial angular momenta waves in the detachment process

Developing a viable community-based tourism project in Botswana: The case of the Chobe Enclave Conservation Trust

Purpose – The purpose of this paper is to compare tourism benefits between the Joint Venture Partnership (JVP) and the traditional Community-Based Natural Resource Management (CBNRM) system at the Chobe Enclave Community Conservation Trust (CECT), Northern Botswana.Design/methodology/approach – The ecotourism conceptual framework informed the study. Unstructured interviews with CECT members and wildlife officers were conducted. Secondary data sources including CECT annual reports and lease agreement documents with the safari company were also used.Findings – Results indicate that the JVP has better tourism benefits (e.g. revenue, decision making) to local CECT communities than the traditional CBNRM system. The JVP also allows communities equally partnership in tourism businesses. For example, communities have 50 per cent shares in the 5-star Ngoma Lodge

Tourism development, rural livelihoods, and conservation in the Okavango Delta, Botswana

This study analyzed changes in livelihoods before and after tourism development at Khwai, Mababe and Sankoyo villages in the Okavango Delta. Specifically, it analyzed how people interacted with species like giraffe (Giraffa camelopardalis), sable antelope (Hippotragus niger) and thatching grass (Cymbopogon excavatus) before and after tourism development. This analysis was expected to measure the effectiveness of tourism development as a tool to improve livelihoods and conservation. The concept of social capital, sustainable livelihoods framework and the Community- Based Natural Resource Management (CBNRM) paradigm informed the study. Qualitative and quantitative data were gathered through field-based research, using tools of participant observation, semi-structured interviews, and key informant interviews. Results indicate that local customs and institutions at Khwai, Mababe and Sankoyo ensured the conservation of resources in pre-colonial Botswana. However, British colonial rule (1885-1966) affected traditional institutions of resource use hence the beginning of resource decline. The British colonial rule and the first 15-20 years after Botswana’s independence from British rule saw an increase in resource degradation. Results also indicate that since CBNRM began in the 1990s, tourism development has positive and negative effects on rural livelihoods. On the positive side, tourism development in some ways is achieving its goals of improved livelihoods and conservation. Residents’ attitudes towards tourism development and conservation have also become positive compared to a decade ago when these communities were not involved in tourism development. On the negative side, tourism is emerging as the single livelihood option causing either a decline or abandonment of traditional options like hunting and gathering and agricultural production. Reliance on tourism alone as a livelihood option is risky in the event of a global social, economic and political instability especially in countries where most tourists that visit the Okavango originate or in Botswana itself. There is need, therefore, for communities to diversify into domestic tourism and small-scale enterprises. On the overall, tourism development through CBNRM indicates that it is a viable tool to achieve improved livelihoods and conservation in the Okavango Delta

Barriers to local residents’ participation in community-based tourism: lessons from Houay Kaeng Village in Laos

This study aims to identify the barriers to local residents’ participation in the process of community-based tourism planning and development in a developing country. Focusing on the case of Houay Kaeng Village in Sayabouly Province, Laos, a qualitative exploratory study was conducted by adopting in-depth interviews with the various levels of local community’s members. The key barriers to local community participation identified in this research include: (1) low education levels and lack of knowledge about tourism; (2) poor living conditions and lack of financial support; (3) busy daily routine and lack of time for tourism participation; (4) local community’s perception of tourism as a seasonal business with low income; and (5) power disparities, institutional disincentives and local’s distrust in authorities. The results suggest that only a small number of the local residents in the village were satisfied with their current and on-going participation expressing their strong willingness to continue in participating in the process of tourism planning and development, whereas a large group of the residents were not willing to do it at all in the future. The paper further discusses implications for the government and communities in regard to community-based sustainable tourism development

Vibronic coupling in the superoxide anion: The vibrational dependence of the photoelectron angular distribution

We present a comprehensive photoelectron imaging study of the O₂(X³Σg⁻,v′=0–6)←O₂⁻(X²Πg,v′′=0) and O₂(a¹Δg,v′=0–4)←O₂⁻(X²Πg,v′′=0)photodetachment bands at wavelengths between 900 and 455 nm, examining the effect of vibronic coupling on the photoelectron angular distribution (PAD). This work extends the v′=1–4 data for detachment into the ground electronic state, presented in a recent communication [R. Mabbs, F. Mbaiwa, J. Wei, M. Van Duzor, S. T. Gibson, S. J. Cavanagh, and B. R. Lewis, Phys. Rev. A82, 011401–R (2010)]. Measured vibronic intensities are compared to Franck–Condon predictions and used as supporting evidence of vibronic coupling. The results are analyzed within the context of the one-electron, zero core contribution (ZCC) model [R. M. Stehman and S. B. Woo, Phys. Rev. A23, 2866 (1981)]. For both bands, the photoelectron anisotropy parameter variation with electron kinetic energy,β(E), displays the characteristics of photodetachment from a d-like orbital, consistent with the π∗g 2p highest occupied molecular orbital of O₂⁻. However, differences exist between the β(E) trends for detachment into different vibrational levels of the X³Σg⁻ and a ¹Δg electronic states of O₂. The ZCC model invokes vibrational channel specific “detachment orbitals” and attributes this behavior to coupling of the electronic and nuclear motion in the parent anion. The spatial extent of the model detachment orbital is dependent on the final state of O₂: the higher the neutral vibrational excitation, the larger the electron binding energy. Although vibronic coupling is ignored in most theoretical treatments of PADs in the direct photodetachment of molecular anions, the present findings clearly show that it can be important. These results represent a benchmark data set for a relatively simple system, upon which to base rigorous tests of more sophisticated models.The authors gratefully acknowledge support by the National Science Foundation Grant No. CHE-0748738 and ANU ARC Discovery Projects under Grant Nos. DP0666267 and DP0880850

The Carbonate-catalyzed Transesterification of Sunflower Oil for Biodiesel Production: in situ Monitoring and Density Functional Theory Calculations

Biodiesel has emerged as a promising alternative fuel to replace dwindling fossil-based resources, particularly in view of its added environmental merit of  reducing additional air pollution. Its specific attraction stems from the similarity of its physical properties to fossil fuel-derived diesel. Although the  production of biodiesel is a relatively straightforward process, reaction progress monitoring and product analysis require costly specialist equipment,  such as gas chromatography and mass spectrometry. In this study, we investigate the use of pH in monitoring the progress of carbonate-catalyzed  transesterification reactions. Specifically, we focus on potassium and sodium carbonates and sunflower oil. Our results are consistent with the results  obtained by other studies using different methods of monitoring. To test the generality of the method, pH measurements were also used to monitor the  progress of the potassium carbonate transesterification reaction in the presence of added water, glycerol and gamma-valerolactone (GVL). The obtained  results are as expected, with a limited amount of water increasing the transesterification rate; glycerol slowing the reaction slightly in accord with Le  Chatellier’s principles; and GVL increasing the rate due to co-solvent effects. Atomic-level insights into the adsorption mechanism of methanol and water  on the (001) surfaces of Na2CO3 and K2CO3 catalysts are provided by first-principles DFT calculations, which explain the increase in transesterification    reaction rate upon the addition of water

The Okavango; a river supporting its people, environment and economic development

The Okavango basin comprises the Cuito and Cubango active catchment areas in Angola, in addition to the Kavango–Okavango non-active catchment in northern Namibia and Botswana. The Okavango River water and its ecosystem resources are critically important sources of livelihoods for people in the basin. Pressures from livelihoods and development are already impacting on the environment. These pressures may increase in the future due to the rapid increase in population, the peace process and associated resettlement activities in Angola, and major development initiatives in Botswana and Namibia. For instance, possible future increase in water abstraction from the Okavango River may affect the long-term environmental sustainability of the Okavango Delta by minimizing channel shifting and thereby reducing spatial biodiversity. The paper argues that while conservation of the natural environment is critical, the pressing development needs must be recognized. The reduction of poverty within the basin should be addressed in order to alleviate adverse effects on the environment. The paper recommends that the development of sustainable tourism and community-based natural resource management initiatives may be appropriate strategies for reaching the Millennium Development Goals of poverty alleviation and achievement of environmental sustainability in the Okavango Basin. These initiatives have a comparative advantage in this area as demonstrated by the performance of the existing projects

Évaluation de la pertinence de la prescription des produits sanguins labiles à l'Hôpital Général de Référence National et à l'Hôpital Mère-Enfant de N’Djamena au Tchad

La transfusion sanguine est un acte Médical qui sauve des vies, à condition d’être effectuée dans les règles de l’art. L’objectif de cette étude était d’évaluer les pratiques en la matière dans notre contexte d’exercice. Il s’agissait d’une étude transversale descriptive multicentrique menée dans deux Hôpitaux Nationaux de référence et au Centre National de Transfusion Sanguine (CNTS). De juillet à septembre 2016, 3002 formulaires de demande de sang parvenus au Centre National de Transfusion Sanguine (CNTS) ont été retenus et analysés. Une interview des malades et/ou parents des malades et la revue des dossiers médicaux ont permis de collecter des données complémentaires. Il ressort de cette analyse que la majorité des demandes des PSL (61,9%) provenaient de l’Hôpital de la Mère et de l’Enfant. Les prescripteurs étaient majoritairement des étudiants en médecine (59,1%) suivis des infirmiers (12,7%) et des sages-femmes (6,4%) contre (6,3%) uniquement des médecins. Cette étude a montré que les prescripteurs de PLS sont majoritairement des étudiants en médecine. Il faut accroître la sensibilisation et la formation pour une meilleure prescription des PSL

Impact of climate change and development scenarios on flow patterns in the Okavango River

This paper lays the foundation for the use of scenario modelling as a tool for integrated water resource management in the Okavango River basin. The Pitman hydrological model is used to assess the impact of various development and climate change scenarios on downstream river flow. The simulated impact on modelled river discharge of increased water use for domestic use, livestock, and informal irrigation (proportional to expected population increase) is very limited. Implementation of all likely potential formal irrigation schemes mentioned in available reports is expected to decrease the annual flow by 2% and the minimum monthly flow by 5%. The maximum possible impact of irrigation on annual average flow is estimated as 8%, with a reduction of minimum monthly flow by 17%. Deforestation of all areas within a 1 km buffer around the rivers is estimated to increase the flow by 6%. However, construction of all potential hydropower reservoirs in the basin may change the monthly mean flow distribution dramatically, although under the assumed operational rules, the impact of the dams is only substantial during wet years. The simulated impacts of climate change are considerable larger that those of the development scenarios (with exception of the high development scenario of hydropower schemes) although the results are sensitive to the choice of GCM and the IPCC SRES greenhouse gas (GHG) emission scenarios. The annual mean water flow predictions for the period 2020-2050 averaged over scenarios from all the four GCMs used in this study are close to the present situation for both the A2 and B2 GHG scenarios. For the 2050-2080 and 2070-2099 periods the all-GCM mean shows a flow decrease of 20% (14%) and 26% (17%) respectively for the A2 (B2) GHG scenarios. However, the uncertainty in the magnitude of simulated future changes remains high. The simulated effect of climate change on minimum monthly flow is proportionally higher