Irrigation water pricing between governmental policies and farmers’ perception: Implications for green-houses horticultural production in Teboulba (Tunisia)

A positive mathematical programming model was constructed in this study to assess the effect of three water pricing scenarios on Teboulba’s agricultural production systems. The effects of these scenarios were estimated for three groups of farmers from three irrigated districts. Results show that water demand in group 1 remains inelastic until achieving the price of 0.20 TD. A price above this level decreases water consumption, farmer’s incomes as well as seasonal labor demand. For groups 2 and 3, the water demand curves remain highly inelastic even with a full cost recovery price. However, once reaching this last price, the model shows important income reductions reaching 20% of the current observed income. Moreover, a pricing policy aiming to recover operational and maintenance costs and which will be implemented independently from other economic, social and environmental measures can threaten the sustainability of the production systems in the region.Water pricing, positive mathematical programming, greenhouses, economic impact, Teboulba, Environmental Economics and Policy, Farm Management, Resource /Energy Economics and Policy, Q15, Q18,

Irrigation water use efficiency in collective irrigated schemes of Tunisia: determinants and potential irrigation cost reduction

This study aims first to measure the farm specific irrigation water use efficiency (IWUE), through non parametric DEA model; and second to evaluate the potential irrigation cost reductions and identify the main factors causing variations in IWUE among the sample farms. Cross sectional data collected from a sample of 75 farms participating in the WaDImena project in Nadhour region (northern Tunisia) was used for this aim. The results showed that the average level of IWUE across the farm sample was around 61.2% under variable returns to scale (VRS) assumption. However, the estimated mean irrigation water technical cost efficiency (ITCE) is much higher than IWUE. Farmers would be able to reduce their actual cost by 5% under VRS by adjusting irrigation water to its efficient level. This low level of cost reductions is consistent with the existing literature about IWUE in Tunisia. Moreover, education level of farmers, access to credit and agricultural extension service showed a positive relationship with the IWUE in our case study.Resource /Energy Economics and Policy,

Investigation of structural effects on the reactivity of heterocyclic bioactive compounds

Tese de dout., Química, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2008In the course of this investigation, structural effects on the reactivity of a series of heterocyclic compounds, in particular tetrazole and benzisothiazole derivatives, submitted to different chemical environments, were explored. The photochemistry of several representative tetrazoles was considered in solution and for the compounds trapped in a rigid matrix of solidified argon at cryogenic temperatures. UV-excitation resulted in photofragmentation of tetrazoles with a wide range of exit channels. Important mechanistic questions concerning the photodecomposition of allyl-tetrazolyl derivatives in different solvents were answered, and new synthetic methodologies for the preparation of heterocyclic compounds, such as pyrimidinones or oxazines, from allyl-tetrazoles, were developed. For the matrix-isolated compounds, since the obtained fragments in general stay in the matrix cage where they are formed, no subsequent cross-reactions involving species resulting from photolysis of different reactant molecules can occur. This fact introduced a useful simplification for the interpretation of the reaction mechanisms. FTIR spectroscopy provided experimental frequencies and intensities of characteristic absorptions of the matrix-isolated chemical species, both for reagents and photoproducts. The analysis of experimental data was assisted by their direct comparison with the vibrational spectra theoretically calculated for the single molecule in vacuum. Spectroscopic characterization of a number of relatively unusual or highly reactive molecules, formed from photolysis of matrix-isolated tetrazoles, is presented for the first time. Novel tetrazolyl and benzisothiazolyl naphthylmethylic ethers were synthesized and the development of experimental conditions for their palladium-catalysed hydrogenolysis, using a hydrogen donor or molecular hydrogen, was carried out successfully. Structural effects on the reactivity of the heteroaromatic ethers were investigated. Furthermore, new benzisothiazole-tetrazolyl derivatives differing on the spacer-group used for linkage of the two heterocyclic systems were designed, produced and tested as multidentate ligands in coordination reactions with transition-metal complexes

Development of Nanoimprint Lithography processes for state-of-the-art light management strategies to be integrated in CIGS solar cells

The growing energy demand requires a strong portfolio of sustainable energy sources, such as photovolta- ics. Notwithstanding, it is imperative to minimize critical raw materials consumption for the implementation of these renewable solutions. In this regard, record-efficiency thin-film solar cells based on Cu(In,Ga)Se2 (CIGS) are moving from a micrometre absorber to the nanometre range – ultrathin. However, incomplete light absorption arising from this thickness reduction calls for light management solutions which, conversely, de- mand a cost-effective and high resolution nanofabrication alternative to develop the sub-wavelength structures. This work presents and discusses nanofabrication procedures for light management solutions compatible with ultrathin CIGS technology, via nanoimprint lithography (NIL). Front and rear strategies were considered, through a broadband anti-reflective moth-eye (ME) structure and two photonic crystal schemes, respectively. A gold nanoparticles etch mask was tailored via a 3-cycle thermal dewetting, followed by an optimized reactive ion-etching (RIE) to fabricate a ME NIL master stamp. Two intermediate polymer stamps were used for the ME replication, with anti-sticking layer studies in each procedure, to ensure good demoulding and high pattern transfer fidelity. Two rear scattering architectures based on dielectric SiO2 photonic crystals were optimized via optical simulations – hemisphere and pillar arrays. A process-flow encompassing an isotropic etch to fab- ricate the master stamp, an inversion NIL step, and an anisotropic etch were developed for the hemispheres architecture. Two RIE approaches with selectivity close to one were employed for the final etch step to produce proof-of-concept hemisphere-like structures. For the pillars array, a master stamp with the simulated dimen- sions was fabricated through a process comprising electron-beam lithography, NIL, RIE, and chemical vapour deposition. The photonic crystals enabled a significant diffuse reflectance increase compared to a Bare Si sample, showing the scattering potential of all developed structures.A demanda energética requer um portfolio sólido de fontes de energia sustentáveis, como a fotovoltaica. Contudo, é imperativo minimizar o consumo de matérias-primas críticas nas soluções renováveis. Neste sen- tido, a transição de uma camada absorvente micrométrica para nanométrica (ultrafino) tem vindo a ocorrer em células solares de Cu(In,Ga)Se2 (CIGS). Porém, a absorção incompleta de luz decorrente desta redução de espessura, requer a implementação de esquemas de manipulação de luz. Todavia, o desenvolvimento de estru- turas com dimensão menor que o comprimento de onda da luz necessita de um processo de nanofabricação que garanta resolução e baixo-custo. Este trabalho apresenta e discute diferentes procedimentos de nanofabri- cação via litografia por nanoimpressão (NIL), para a integração de esquemas de manipulação de luz na tecno- logia CIGS. Duas estratégias, para a superfície frontal – através da estrutura anti-refletora “moth-eye” (ME), e para o contacto posterior – através de dois esquemas de cristais fotónicos, foram estudadas. Desenvolveu-se uma máscara de nanopartículas de ouro via 3-ciclos de “thermal dewetting”, seguido de erosão reativa iónica (RIE) para um molde ME para NIL. Usaram-se dois moldes poliméricos intermédios para replicar a ME, com estudos da camada antiaderente para assegurar um bom desmolde e fidelidade no padrão transferido. Otimiza- ram-se duas arquiteturas para dispersão de luz baseadas em cristais fotónicos de SiO2 através de simulações óticas – matrizes de hemisférios e pilares. Para os hemisférios desenvolveu-se um procedimento que engloba erosão isotrópica para o molde, NIL para inversão e erosão anisotrópica. Finalmente, duas opções de RIE com seletividade ~1 foram usadas para produzir provas-de-conceito de estruturas hemisféricas. Para a matriz de pilares, fabricou-se um molde com as dimensões simuladas via litografia de feixe de eletrões, NIL, RIE e deposição química de vapor. Os cristais fotónicos exibiram um aumento significativo da refletância difusa comparativamente ao Si, demonstrando o potencial para uma eficiente dispersão de luz

Effect of changes in the institutional structure of irrigation water property rights on the willingness to pay of farmers for water: case of Tunisia

This paper assesses the economic value of changes in the attributes of farmers’ irrigation water property rights in Tunisia. Changes on attributes generated by the transfer process of the property rights from the collective to the individual level in addition to changes in “constitutional” attributes were integrated into three scenarios. The valuation was conducted using the Contingent Valuation Method through the elicitation of individuals’ willingness to pay. Results show positive willingness to pay values for all scenarios. However, farmers of the studied region are shown willing to pay more for changes in the constitutional attributes. Furthermore their willingness to pay appears to be most affected by their perceptions concerning the organization and the functioning of the water users’ association to which they belong and by their productivity.Property rights, irrigation water, Contingent Valuation, Resource /Energy Economics and Policy,

Ethical Leadership Antecedents Review: Call for More Research Contextualization & Proposition of Conceptual Framework

Ethical leadership has been investigated as a standalone area because of scholars’ notable focus on ethical leaders’ behaviors instead of examining other leadership styles’ (e.g., transformational, transactional, charismatic leadership) ethical dimensions. The present article reviews ethical leadership literature focusing on variables driving its emergence. The area with most hanging fruits is the role of individual traits (e.g., personality traits, Kalshoven et al. 2011; and moral identity, Mayer et al. 2012) in shaping ethical leadership. However, still little is known about context’s contribution in understanding leaders’ important ethicality. To address this gap, based on Johns (2006) context framework, we have recognized and classified existing antecedents from a context stand, and analyzed their effect on ethical leaders’ emergence. Yet, the empirical research body exploring contextual variables is focused on specific areas and is not systematic. At discrete context level, organization’s characteristics (e.g., ethical climate, organizational justice) and social network have important credits in forming ethical leadership with a deficient focus on omnibus contextual variables. Our review raises calls for considering three main avenues. Firstly, we encourage more research about omnibus contextual factors specifically “when” and “who” to make the story telling about ethical leadership predictors more comprehensive. Secondly, since they are nested within the omnibus context, discrete contextual factors might be considered for their possible moderating effect on the investigated relationship. Thirdly, as contexts are dynamic, interactionist approach between omnibuses and discrete contextual variables can offer meaningful discussions about ethical leadership. A framework (figure 2) is proposed enclosing individual traits and contextual factors impacting ethical leadership.   JEL Classification: D23, O15 Paper Type: Theoretical Research  Ethical leadership has been investigated as a standalone area because of scholars’ notable focus on ethical leaders’ behaviors instead of examining other leadership styles’ (e.g., transformational, transactional, charismatic leadership) ethical dimensions. The present article reviews ethical leadership literature focusing on variables driving its emergence. The area with most hanging fruits is the role of individual traits (e.g., personality traits, Kalshoven et al. 2011; and moral identity, Mayer et al. 2012) in shaping ethical leadership. However, still little is known about context’s contribution in understanding leaders’ important ethicality. To address this gap, based on Johns (2006) context framework, we have recognized and classified existing antecedents from a context stand, and analyzed their effect on ethical leaders’ emergence. Yet, the empirical research body exploring contextual variables is focused on specific areas and is not systematic. At discrete context level, organization’s characteristics (e.g., ethical climate, organizational justice) and social network have important credits in forming ethical leadership with a deficient focus on omnibus contextual variables. Our review raises calls for considering three main avenues. Firstly, we encourage more research about omnibus contextual factors specifically “when” and “who” to make the story telling about ethical leadership predictors more comprehensive. Secondly, since they are nested within the omnibus context, discrete contextual factors might be considered for their possible moderating effect on the investigated relationship. Thirdly, as contexts are dynamic, interactionist approach between omnibuses and discrete contextual variables can offer meaningful discussions about ethical leadership. A framework (figure 2) is proposed enclosing individual traits and contextual factors impacting ethical leadership.   JEL Classification: D23, O15 Paper Type: Theoretical Research &nbsp