1,612 research outputs found
THE EFFECTS OF SPOT WATER MARKETS ON THE ECONOMIC RISK DERIVED FROM VARIABLE WATER SUPPLY
Water availability in semiarid regions commonly exhibits patterns of extreme variability. Even in basins with large infrastructure development, some users are subject to low levels of water reliability, incurring economic losses during periods of scarcity. More flexible instruments, such as voluntary exchanges of water among users, may help users reduce their risk exposure. Recent changes in the Spanish water Law have given an initial impulse to allow for lease-out contracts of water use rights. This paper analyses, from theoretical and empirical standpoints, the effect that establishing water markets has on the economic risk caused by water availability variations. The empirical study is performed on an irrigation district of the Guadalquivir Valley (Spain) with fair levels of average water availability but a high probability of periods of extreme scarcity. A non-linear programming model is used to simulate irrigators' behaviour and derive water demand functions. Another spatial equilibrium model is used to compute market exchange and equilibrium. These programming models are combined with statistical simulation techniques. It is shown that the probability distribution of profits for a representative irrigator is modified if water exchanges are authorised, resulting in unambiguous risk reductions. Results also suggests that if the market would be extended to several irrigation districts and users, each characterised by different hydrological risk exposure, the occurrence of extremely low benefits events would become more unlikely. In sum, it is shown that exchanging water in annual spot markets allows for the reduction of farmers' economic vulnerability caused by the variability of water supply across irrigation seasons.Resource /Energy Economics and Policy,
Gender Needs Awareness and Gender Asymmetry: An Analysis of a Rural Women Survey in Mountainous Areas of South-eastern Spain
Achieving gender symmetry in rural areas is an important target for the European Union. There is no shortage of talent, ideas and energy amongst women in rural areas, nor are there legal constraints. However, a range of cultural obstacles still stand in the way of their full participation in rural development (the persistence of traditional views about women's and men's roles in society, etc.) particularly in the Mediterranean areas. The integration of equal opportunities will no longer be a choice, but it will be an obligation in the design and implementation of rural development programmes and projects. Some European initiatives (NOW, EQUAL, LEADER, etc.) have already been taken to improve rural women's opportunities to participate more actively in economic and public life. In this context, surveying and the data collection will be considered an important preliminary step in the implementation of gender symmetry-focused development policies. In this paper, after briefly discussing the different gender paradigms in rural development, some results of a survey conducted on 304 rural women living in mountainous rural areas of the province of Granada (Southern Spain) are presented. The position of rural women as regards employment, family, socio-cultural, institutional matters, etc., is described. Then women's perception and awareness regarding both practical and strategic gender needs in the area are analysed. Factors related to how women stand with respect to gender needs have been identified using the probit regression model. From the above results, some conclusions have finally been drawn that could be helpful for designing strategies to achieve a better level of gender symmetry in the region, focusing sustainable rural development on a "gender planning" approach.gender needs, rural development, gender asymmetry, Southeastern Spain, Community/Rural/Urban Development, Labor and Human Capital, O18, Q01, R13,
Modelling Spot Water Markets Under Uncertain Water Supply
Water availability in semiarid regions usually exhibits patterns of extreme variability. Even in intensively controlled basins, some users are subject to low levels of water reliability, and more vulnerable to periods of extreme scarcity. To reduce their risk exposure more flexible instruments, such as voluntary exchanges of water among users, are required. Recent changes in the Spanish water Law have given an initial impulse to allow for leases of water use rights. Properly designed and monitored, this instrument provides some flexibility to water management, and may increase the economic use efficiency as well as mitigate the adverse economic effects of droughts. This paper looks at the risks and uncertainty dimensions of water markets, which have not been paid much attention in the literature. It analyses, from theoretical and empirical standpoints, the role that uncertainty plays in market participants' decisions and its impact on gains from trade. Two models have been developed to carry out the empirical application. One is a stochastic and two-stage discreet programming model which simulates irrigators behaviour and the other is a spatial equilibrium model to compute market exchange and equilibrium. Water market price endogeneity is solved by an iterative process, which characterise price uncertainty from the results obtained from the spatial equilibrium model. Hydrological risk is characterised at the irrigation farm level through the variation of the water allowances served for irrigation. The application is performed on eleven irrigated farms in a district of the Guadalquivir Valley (Southern Spain. It is shown how water availability uncertainty reduces farmers' benefits because of the fact that they must take ex-ante decisions. However, if market participation is allowed once water allowances become known, even at an uncertain price, the benefit losses are partly mitigated. From a methodological standpoint, these results suggest that the agricultural water market benefits estimates found in the literature may be undervalued as a result of omitting the option to participate in the market in the mix of possible strategies. Exchanging water in annual spot markets allows for the reduction of farmers' economic vulnerability caused by the variability and uncertainty of water supply within an irrigation season.uncertainty, farm modelling, water markets, water supply, Resource /Energy Economics and Policy,
Factors Related to the Adoption of Good Agrarian Practices (GAP) in Plastic Covered Horticulture of Southeastern Spain
The adoption by farmers of Good Agrarian Practices (GAP), that favouring the environment and assure food quality and safety, is being a frequent fact. Considering the plastic covered horticulture, these kind of practices can be of different nature: use of organic fertiliser, made of crops rotations, use of recyclable plastic as greenhouse cover, good management of organic residuals (use of containers), recycling of plastic containers, etc. This paper, wich try to analyse the adoption of GAP by protected vegetable growers, is based on a survey carried out to 114 farmers in the southeast coastline of Spain, asking for the level of adoption of a set of GAP. From the information gathered on the suvey, an aggregated index of adoption has been performed, and the relationship between this index and some structural and managerial characteristics of the greenhouses, and some sociocultural variables of the growers (age, study, agrarian formation, etc) has been analysed, trying to identify factors related to adoption of GAP, which could probably help to design strategies for the increase of the level of GAP adoption in the system.Crop Production/Industries,
A Multifunctional Comparison of Conventional versus Alternative Olive Systems in Spain by Using AHP
Sustainability of agriculture is strongly related to the multifunctional role implicitly or explicitly recognized to it in the framework of the European Union CAP. This multifunctional role entails a multicriteria approach when assessing the performance and value for society of farming systems. Multicriteria assessment of agricultural systems is characterized by the existence of many criteria often conflicting among then, many stakeholders and decision-makers with competing interests, and lack of information. Analytic Hierarchy Process (AHP) is a multicriteria methodology that allows dealing with these problems, in a relatively easy, flexible and economical manner, and therefore it is a potentially useful tool in this field, although its application with this purpose has not been found in the literature. Therefore, this paper aims (1) to present AHP as a useful methodology to effectively assess and compare the multifunctional performances of agricultural systems, and (2) to apply AHP in the comparison, on the basis of experts' knowledge, of multiple functions -economic, technical, sociocultural and environmental- of conventional, organic and integrated olive producing systems in a region of Spain, and test the hypothetical superiority of the alternative systems with respect to the conventional one in the medium/long term and the average conditions of the region. Results confirm this global superiority thus providing a scientific base to endorse institutional and social support regarding the promotion and implementation of these alternative farming techniques. However, environmental issues are the more conflictive among experts and require a more in depth research in the future to clarify many of them.organic farming, integrated farming, olive-growing systems, AHP, multicriteria analysis., Crop Production/Industries, Q50, Q57, Q51, Q56, C6,
Adoption of Soil Erosion Control Practices in Southern Spain Olive Groves
This paper presents results from a survey carried out in 2005 among 147 olive tree farmers from the Alto Genil River Basin in Southern Spain regarding the adoption of soil conservation and management practices. Olive tree groves in South-eastern Spain's mountainous areas are subject to a high risk of soil erosion and have to incur in high costs of soil conservation. This results in great difficulties to comply with cross-compliance and to benefit from agri-environmental schemes. Our main objectives are to analyse the current level of adoption of soil conservation practices and to analyse which socio-economic and institutional factors determine such adoption. Three Probit models are estimated. Dependant variables are three different soil conservation practices, namely tillage following contour lines, maintaining the rests of pruning on the ground, and non-tillage with weedicides.olive groves, soil erosion, soil conservation, cross compliance, Crop Production/Industries, Q12, Q24,
Adoption and diffusion of no tillage practices in Southern Spain olive groves
This paper analyses the process of adoption of no tillage in South-eastern Spain’s olive groves. Olive tree groves in South-eastern Spain’s mountainous areas are subject to a high risk of soil erosion, which is the main environmental problem for this crop, and have to incur in high costs of soil conservation. This results in a greater difficulty to comply with the practices required to benefit from both the single payment and agri-environmental schemes. In many high-steeped areas, farmers have opted for non-tillage practices as an alternative to other conservation practices. Using our own data from a survey carried out in 2006 among 215 olive tree farmers from the Granada Province in Southern Spain regarding the adoption of soil conservation and management practices, we model the diffusion process of no tillage practices using several specifications (logistic, Gompertz and exponential). We also estimate an ordered probit model to analyse which socio-economic and institutional factors determine the adoption of no tillage. Our results show that 90% of farmers in the area of study perform no tillage with either localized (21%) or no localized (69%) application of weedicides. The diffusion process of no tillage has been very intense since the middle nineties, and has been based on the interactions among farmers in the area of study rather than in external factors such as EU policies or extension services. Among other relevant factors that positively affect the adoption of no tillage practices in general, such as farm size and irrigation, the probability of a farmer adopting no tillage with non-localized application of weedicides increases when there is a relative that will continue with the farming activity, what causes the farmer to incorporate long term effects in his farming decisions, when the farmer is only a manager or when he bought the farm rather than inherited it (i.e. on more professionalized farms), and with his educational level. These results confirm some findings from previous studies in other nearby areas.Spanish olive groves, soil erosion, no tillage, Crop Production/Industries, Land Economics/Use,
Uso del nitrógeno en algas: desvelando piezas del rompecabezas de la asimilación del nitrógeno y su regulación en el alga modelo Chlamydomonas reinhardtii
Las algas, formando parte de la base de la cadena trófica de ecosistemas
marinos y de agua dulce, son clave para la vida acuática. Estos organismos
fotosintéticos, sometidos a fluctuaciones constantes de disponibilidad de
nutrientes, muestran un alto nivel de adaptabilidad a estos ambientes
dinámicos. Aunque el nitrógeno (N), nutriente esencial para la vida, es
comúnmente usado por las algas en su forma inorgánica, algunas especies de
algas pueden usar compuestos de N orgánico, los cuales pueden ser
especialmente abundantes debido a la escorrentía y filtrado de áreas fertilizadas
de forma intensiva. El alga modelo Chlamydomonas reinhardtii
(Chlamydomonas) puede consumir fuentes de nitrógeno inorgánico (amonio,
nitrato y nitrito), así como L-arginina y urea. Además, este alga presenta una Laminoácido
oxidasa extracelular (LAO1) que desamina un amplio rango de
aminoácidos. En este trabajo hemos estudiado el control de la señalización que
da lugar a la preferencia de nitrato sobre N orgánico en Chlamydomonas, el
papel clave de LAO1 en el uso de aminoácidos y péptidos, así como el
establecimiento de nuevas interacciones mutualistas con bacterias que
promueven el crecimiento en N orgánico.
Capítulo 1
El factor de transcripción NIT2 es el regulador clave de los genes de la
asimilación de nitrato en Chlamydomonas. En primer lugar, comparamos el
transcriptoma de una estirpe silvestre y otra mutante nit2 de Chlamydomonas
en respuesta a nitrato. Observamos que nitrato y NIT2 reprimen los genes
involucrados en el uso de fuentes de N orgánicas, incluyendo LAO1. Mediante
el uso de mutantes de Chlamydomonas demostramos que tanto el nitrato como
el nitrito afectan negativamente el uso de aminoácidos por este alga.
Capítulo 2
Las enzimas L-aminoácido oxidasa (LAAO, L-Amino Acid Oxidase) están
ampliamente distribuidas en la naturaleza y se propone que su papel principal
en hongos y algas es la captación de nitrógeno. Mediante búsquedas
genómicas comparativas, no pudimos encontrar ningún ortólogo de LAO1 en
ningún alga verde ni en plantas, pero identificamos ortólogos en 10 de otras 27
especies de algas, incluyendo Rhodophyta, Alveolata, Heterokonta, Haptophyta
y Dinophyta. La construcción de un árbol filogenético de enzimas LAAO reveló
que las secuencias identificadas como ortólogas de LAO1 -denominadas aquí
como ALAAOs (Algal LAAOs)-, se agrupaban en la misma rama evolutiva.
Observamos que en Chlamydomonas el gen LAO1 está situado adyacente a un
gen que codifica una putativa proteína RidA, que resultó estar evolutivamente
cercana a la de cianobacterias. Nuestro análisis filogenético apoya la idea de
que las proteínas ALAAOs pueden tener un origen en el ancestro común de las
algas, el cual se originó por la endosimbiosis de una cianobacteria por un
protista. Mediante el uso de un mutante lao1 hemos mostrado que LAO1 era crucial para el crecimiento de Chlamydomonas en 16 de 20 aminoácidos
proteinogénicos, así como para algunos di-/tri-péptidos.
Además de amonio, las enzimas LAAO producen el correspondiente
cetoácido y peróxido de hidrógeno. Hemos demostrado que la reacción
espontánea de los productos derivados de la desaminación por LAO1 de Lalanina
-ácido pirúvico y peróxido de hidrógeno- genera ácido acético.
Capítulo 3
Aunque Chlamydomonas puede crecer en la mayoría de los L-aminoácidos y en
algunos di-/tri-péptidos como únicas fuentes de N, este crecimiento es mucho
menos eficiente que en fuentes de N inorgánicas, y además, algunos
aminoácidos y péptidos no pueden ser usados por este alga. De forma fortuita
descubrimos una contaminación Methylobacterium sp. que permitió el
crecimiento de Chlamydomonas en un di-péptido que no puede asimilar. Las
especies de Methylobacterium están incluidas en el grupo de bacterias
promotoras del crecimiento de plantas (PGPB, del inglés Plant Growth-
Promoting Bacteria), las cuales mejoran el crecimiento de las plantas. Tras el
muestreo en campo, aislamiento e identificación de bacterias, encontramos que
algunas especies salvajes, incluidas en los géneros Methylobacterium,
Sphingomonas, Deinococcus y Chitinophagaceae, mejoran el crecimiento de
Chlamydomonas en L-serina. Además, algunas especies de Methylobacterium
permitieron el crecimiento de Chlamydomonas en algunos aminoácidos y
péptidos que este alga no puede usar. Hemos demostrado un nuevo
mutualismo basado en un intercambio metabólico de carbono y nitrógeno entre
Chlamydomonas y M. aquaticum. Por otro lado, algunas especies de
Methylobacterium mejoraron el crecimiento de Chlamydomonas en
aminoácidos asimilables. Para esta mejora, la enzima LAO1 fue esencial para el
crecimiento del consorcio con algunas estirpes de Methylobacterium,
incluyendo M. extorquens, M. hispanicum y M. organophilum.
La comunicación química en la interacción entre organismos diferentes
media las relaciones simbióticas. Entre estas moléculas de señalización, el ácido
indolacético es una de las más estudiadas. Descubrimos que la producción de
índoles dependiente de L-triptófano por Chlamydomonas, observada aquí por
primera vez, disminuyó significativamente en el mutante lao1. Además,
observamos que altas concentraciones de ácido indolacético (> 30 μM) inhibe el
crecimiento de Chlamydomonas y que esta inhibición se puede reducir por la
presencia de especies de Methylobacterium.Algae, lying on the basis of food webs in marine and freshwater ecosystems, are
key for aquatic life. These photosynthetic organisms live under continuously
fluctuating nutrients availability, showing a high level of adaptability to these
dynamic environments. Although the essential nutrient Nitrogen (N) is usually
used by algae in its inorganic form, some algal species can use organic N
compounds, which may become especially abundant due to terrestrial leaking
and runoff of highly fertilized areas. The model alga Chlamydomonas reinhardtii
(Chlamydomonas) uptakes inorganic N sources (i.e. ammonium, nitrate and
nitrite), as well as L-arginine and urea. Moreover, this alga presents an
extracellular L-amino acid oxidase (LAO1) with a broad substrate specificity that
scavenges N from L-amino acids. In this work we studied the signaling control
that leads the preference for nitrate over organic N in Chlamydomonas, the key
role of LAO1 in the use of amino acids and peptides, as well as the establishment
of new mutualistic interactions with bacteria to facilitate growth on organic N.
Chapter 1
The transcription factor NIT2 is the key regulator of nitrate assimilation genes in
Chlamydomonas. First, we compared the transcriptome of Chlamydomonas wild
type (WT) and a nit2 mutant in response to nitrate. We observed that nitrate and
NIT2 down-regulated genes involved in organic N scavenging, including LAO1.
By the use of Chlamydomonas mutant strains we demonstrated that both nitrate
and nitrite negatively impact the use of amino acids by this alga.
Chapter 2
L-amino acid oxidase (LAAO) enzymes are widely present in nature and a major
role as N scavenger has been proposed in fungal and algal LAAOs. By
comparative genomic searches, we could not find any LAO1 ortholog in any
green plant or plant, but we identified orthologs in 10 out of 27 other algal
species, including Rhodophyta, Alveolata, Heterokonta, Haptophyta and
Dinophyta algae. The construction of a LAAO phylogenetic tree revealed that
algal protein sequences identified as LAO1 orthologs -named here as ALAAOs
(Algal LAAOs)-, clustered on the same evolutionary branch. We observed that
Chlamydomonas LAO1 gene is clustered to a putative RidA gene (LAO2), which
resulted to be closely related to cyanobacterial members. Our phylogenetic
analysis favoured the idea that ALAAOs may have a common origin in the
archaeplastidan ancestor, originated by a protist engulfing cyanobacteria. By the
use of a lao1 mutant, we showed that LAO1 was crucial for Chlamydomonas
growth on 16 out of 20 proteinogenic amino acids, as well as for some di- and
tripeptides.
Besides ammonium, LAAO produces keto acids and hydrogen peroxide.
We have demonstrated that the spontaneous reaction of the LAO1-derived
products generated by L-alanine deamination, pyruvic acid and hydrogen
peroxide, generates acetic acid. Chapter 3
Although Chlamydomonas can grow on most amino acids and some di-/tripeptides
as the sole N sources, this growth is far less efficient than that on
inorganic N, and yet, there are some amino acids and peptides that cannot be
used by this alga. We serendipitously found a contaminating Methylobacterium
sp. that allowed Chlamydomonas growth on a dipeptide that is not readily
assimilated by this alga. Methylobacterium spp. are included in the PGPB group
of bacteria (Plant Growth-Promoting Bacteria), which improve plant growth and
fitness. After field sampling, isolation and identification of some bacteria, we
found that some wild species, included in Methylobacterium, Sphingomonas,
Deinococcus, and Chitinophagaceae genera, promoted Chlamydomonas
growth on L-serine. Moreover, some Methylobacterium spp. allowed
Chlamydomonas growth on amino acids and peptides that are not used by this
alga. We have demonstrated a new mutualism based on carbon-nitrogen
metabolic exchange between Chlamydomonas and M. aquaticum. Otherwise,
some Methylobacterium spp. improved Chlamydomonas growth on assimilable
amino acids. For this growth promotion, LAO1 was crucial for consortia growth
with some Methylobacterium spp., including M. extorquens, M. hispanicum and
M. organophilum.
The chemical cross-talk between interacting organisms mediates the
beneficial and pathogenic symbiotic relationships. Within these inter-kingdom
signal molecules IAA (Indole-3-Acetic Acid) is one of the best studied. We found
that L-tryptophan-dependent indoles production in Chlamydomonas, observed
here for the first time, was significantly reduced in the lao1 mutant. Moreover,
we observed that high levels of exogenously added IAA (> 30 μM) inhibits
Chlamydomonas growth and that this inhibition may be relieved by the presence
of Methylobacterium spp
Posibles claves para rediseñar las relaciones euromediterráneas
Reseña de:
Jerch, Martin, Democracia, desarrollo y paz en el Mediterráneo. Un análisis de las relaciones entre Europa y el mundo árabe, Universidad Autónoma de Madrid, Madrid, 200
Technical versus institutional innovation in andalusian olive tree orchards: an adoptin modelling analysis.
A survey carried out among olive tree growers in different districts of southern Spain allows the identification and analysis of factors related with adoption of several technical and institutional innovations. At that respect, a composite numerical index has been performed including all innovations considered, among then the following: changes in orchard structure, non or reduced tillage, use of tree vibrators for harvesting, non conventional methods for fighting pests and diseases, keeping an accounting systems, annual farm planning, level of information and awareness of the European CMO in relation to olive oils, etc. Structural and managerial variables of the orchard and personal characteristics of the grower, related to the composite innovation index, have been identified. In a second step, two similar separate analysis have been made for both technical and institutional innovations, and several conclusions have, finally, been drawn concerning factors that should enhance both types of innovations adoption in Spanish olive orchards
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