Showing papers by "University of Córdoba (Spain) published in 2009"

The development of Assessment of SpondyloArthritis international Society classification criteria for axial spondyloarthritis (part II): validation and final selection

Abstract: Objective: To validate and refine two sets of candidate criteria for the classification/diagnosis of axial spondyloarthritis (SpA). Methods: All Assessment of SpondyloArthritis international Society (ASAS) members were invited to include consecutively new patients with chronic (⩾3 months) back pain of unknown origin that began before 45 years of age. The candidate criteria were first tested in the entire cohort of 649 patients from 25 centres, and then refined in a random selection of 40% of cases and thereafter validated in the remaining 60%. Results: Upon diagnostic work-up, axial SpA was diagnosed in 60.2% of the cohort. Of these, 70% did not fulfil modified New York criteria and, therefore, were classified as having “non-radiographic” axial SpA. Refinement of the candidate criteria resulted in new ASAS classification criteria that are defined as: the presence of sacroiliitis by radiography or by magnetic resonance imaging (MRI) plus at least one SpA feature (“imaging arm”) or the presence of HLA-B27 plus at least two SpA features (“clinical arm”). The sensitivity and specificity of the entire set of the new criteria were 82.9% and 84.4%, and for the imaging arm alone 66.2% and 97.3%, respectively. The specificity of the new criteria was much better than that of the European Spondylarthropathy Study Group criteria modified for MRI (sensitivity 85.1%, specificity 65.1%) and slightly better than that of the modified Amor criteria (sensitivity 82.9, specificity 77.5%). Conclusion: The new ASAS classification criteria for axial SpA can reliably classify patients for clinical studies and may help rheumatologists in clinical practice in diagnosing axial SpA in those with chronic back pain. Trial registration number: NCT00328068.

Causes and consequences of variation in leaf mass per area (LMA): a meta-analysis.

Abstract: Here, we analysed a wide range of literature data on the leaf dry mass per unit area (LMA). In nature, LMA varies more than 100-fold among species. Part of this variation (c. 35%) can be ascribed to differences between functional groups, with evergreen species having the highest LMA, but most of the variation is within groups or biomes. When grown in the same controlled environment, leaf succulents and woody evergreen, perennial or slow-growing species have inherently high LMA. Within most of the functional groups studied, high-LMA species show higher leaf tissue densities. However, differences between evergreen and deciduous species result from larger volumes per area (thickness). Response curves constructed from experiments under controlled conditions showed that LMA varied strongly with light, temperature and submergence, moderately with CO2 concentration and nutrient and water stress, and marginally under most other conditions. Functional groups differed in the plasticity of LMA to these gradients. The physiological regulation is still unclear, but the consequences of variation in LMA and the suite of traits interconnected with it are strong. This trait complex is an important factor determining the fitness of species in their environment and affects various ecosystem processes.

AquaCrop-The FAO Crop Model to Simulate Yield Response to Water: I. Concepts and Underlying Principles

Abstract: This article introduces the FAO crop model AquaCrop. It simulates attainable yields of major herbaceous crops as a function of water consumption under rainfed, supplemental, deficit, and full irrigation conditions. The growth engine of AquaCrop is water-driven, in that transpiration is calculated first and translated into biomass using a conservative, crop-specific parameter: the biomass water productivity, normalized for atmospheric evaporative demand and air CO 2 concentration. The normalization is to make AquaCrop applicable to diverse locations and seasons. Simulations are performed on thermal time, but can be on calendar time, in daily time-steps. The model uses canopy ground cover instead of leaf area index (LAI) as the basis to calculate transpiration and to separate out soil evaporation from transpiration. Crop yield is calculated as the product of biomass and harvest index (HI). At the start of yield formation period, HI increases linearly with time after a lag phase, until near physiological maturity. Other than for the yield, there is no biomass partitioning into the various organs. Crop responses to water deficits are simulated with four modifiers that are functions of fractional available soil water modulated by evaporative demand, based on the differential sensitivity to water stress of four key plant processes: canopy expansion, stomatal control of transpiration, canopy senescence, and HI. The HI can be modified negatively or positively, depending on stress level, timing, and canopy duration. AquaCrop uses a relatively small number of parameters (explicit and mostly intuitive) and attempts to balance simplicity, accuracy, and robustness. The model is aimed mainly at practitioner-type end-users such as those working for extension services, consulting engineers, governmental agencies, nongovernmental organizations, and various kinds of farmers associations. It is also designed to fit the need of economists and policy specialists who use simple models for planning and scenario analysis.

The development of Assessment of SpondyloArthritis international Society classification criteria for axial spondyloarthritis (part I): classification of paper patients by expert opinion including uncertainty appraisal

Abstract: Objective: Non-radiographic axial spondyloarthritis (SpA) is characterised by a lack of definitive radiographic sacroiliitis and is considered an early stage of ankylosing spondylitis. The objective of this study was to develop candidate classification criteria for axial SpA that include patients with but also without radiographic sacroiliitis. Methods: Seventy-one patients with possible axial SpA, most of whom were lacking definite radiographic sacroiliitis, were reviewed as “paper patients” by 20 experts from the Assessment of SpondyloArthritis international Society (ASAS). Unequivocally classifiable patients were identified based on the aggregate expert opinion in conjunction with the expert-reported level of certainty of their judgement. Draft criteria for axial SpA were formulated and tested using classifiable patients. Results: Active sacroiliitis on magnetic resonance imaging (MRI) (odds ratio 45, 95% CI 5.3 to 383; p x rays in conjunction with one SpA feature or, if sacroilitiis is absent, in the presence of at least three SpA features. In a second set of candidate criteria, inflammatory back pain is obligatory in the clinical arm (sensitivity 86.1%; specificity 94.7%). Conclusion: The ASAS group has developed candidate criteria for the classification of axial SpA that include patients without radiographic sacroiliitis. The candidate criteria need to be validated in an independent international study.

Sustainable Preparation of Supported Metal Nanoparticles and Their Applications in Catalysis

Abstract: Metal nanoparticles have attracted much attention over the last decade owing to their unique properties as compared to their bulk metal equivalents, including a large surface-to-volume ratio and tunable shapes. To control the properties of nanoparticles with particular respect to shape, size and dispersity is imperative, as these will determine the activity in the desired application. Supported metal nanoparticles are widely employed in catalysis. Recent advances in controlling the shape and size of nanoparticles have opened the possibility to optimise the particle geometry for enhanced catalytic activity, providing the optimum size and surface properties for specific applications. This Review describes the state of the art with respect to the preparation and use of supported metal nanoparticles in catalysis. The main groups of such nanoparticles (noble and transition metal nanoparticles) are highlighted and future prospects are discussed.

New criteria for inflammatory back pain in patients with chronic back pain: a real patient exercise by experts from the Assessment of SpondyloArthritis international Society (ASAS)

Abstract: Objective: Inflammatory back pain (IBP) is an important clinical symptom in patients with axial spondyloarthritis (SpA), and relevant for classification and diagnosis. In the present report, a new approach for the development of IBP classification criteria is discussed. Methods: Rheumatologists (n = 13) who are experts in SpA took part in a 2-day international workshop to investigate 20 patients with back pain and possible SpA. Each expert documented the presence/absence of clinical parameters typical for IBP, and judged whether IBP was considered present or absent based on the received information. This expert judgement was used as the dependent variable in a logistic regression analysis in order to identify those individual IBP parameters that contributed best to a diagnosis of IBP. The new set of IBP criteria was validated in a separate cohort of patients (n = 648). Results: Five parameters best explained IBP according to the experts. These were: (1) improvement with exercise (odds ratio (OR) 23.1); (2) pain at night (OR 20.4); (3) insidious onset (OR 12.7); (4) age at onset Conclusion: This new approach with real patients defines a set of IBP definition criteria using overall expert judgement on IBP as the gold standard. The IBP experts’ criteria are robust, easy to apply and have good face validity.

Tuneable porous carbonaceous materials from renewable resources

Abstract: Porous carbon materials are ubiquitous with a wide range of technologically important applications, including separation science, heterogeneous catalyst supports, water purification filters, stationary phase materials, as well as the developing future areas of energy generation and storage applications. Hard template routes to ordered mesoporous carbons are well established, but whilst offering different mesoscopic textural phases, the surface of the material is difficult to chemically post-modify and processing is energy, resource and step intensive. The production of carbon materials from biomass (i.e.sugars or polysaccharides) is a relatively new but rapidly expanding research area. In this tutorial review, we compare and contrast recently reported routes to the preparation of porous carbon materials derived from renewable resources, with examples of our previously reported mesoporous polysaccharide-derived “Starbon®” carbonaceous material technology.

The nodule inception‐like protein 7 modulates nitrate sensing and metabolism in Arabidopsis

Abstract: Nitrate is an essential nutrient, and is involved in many adaptive responses of plants, such as localized proliferation of roots, flowering or stomatal movements. How such nitrate-specific mechanisms are regulated at the molecular level is poorly understood. Although the Arabidopsis ANR1 transcription factor appears to control stimulation of lateral root elongation in response to nitrate, no regulators of nitrate assimilation have so far been identified in higher plants. Legume-specific symbiotic nitrogen fixation is under the control of the putative transcription factor, NIN, in Lotus japonicus. Recently, the algal homologue NIT2 was found to regulate nitrate assimilation. Here we report that Arabidopsis thaliana NIN-like protein 7 (NLP7) knockout mutants constitutively show several features of nitrogen-starved plants, and that they are tolerant to drought stress. We show that nlp7 mutants are impaired in transduction of the nitrate signal, and that the NLP7 expression pattern is consistent with a function of NLP7 in the sensing of nitrogen. Translational fusions with GFP showed a nuclear localization for the NLP7 putative transcription factor. We propose NLP7 as an important element of the nitrate signal transduction pathway and as a new regulatory protein specific for nitrogen assimilation in non-nodulating plants.

Discovery of potent kisspeptin antagonists delineate physiological mechanisms of gonadotropin regulation

Abstract: Neurons that produce gonadotropin-releasing hormone (GnRH) are the final common pathway by which the brain regulates reproduction. GnRH neurons are regulated by an afferent network of kisspeptin-producing neurons. Kisspeptin binds to its cognate receptor on GnRH neurons and stimulates their activity, which in turn provides an obligatory signal for GnRH secretion, thus gating down-stream events supporting reproduction. We have developed kisspeptin antagonists to facilitate the direct determination of the role of kisspeptin neurons in the neuroendocrine regulation of reproduction. In vitro and in vivo studies of analogues of kisspeptin-10 with amino substitutions have identified several potent and specific antagonists. A selected antagonist was shown to inhibit the firing of GnRH neurons in the brain of the mouse and to reduce pulsatile GnRH secretion in female pubertal monkeys; the later supporting a key role of kisspeptin in puberty onset. This analog also inhibited the kisspeptin-induced release of luteinizing hormone (LH) in rats and mice and blocked the postcastration rise in LH in sheep, rats, and mice, suggesting that kisspeptin neurons mediate the negative feedback effect of sex steroids on gonadotropin secretion in mammals. The development of kisspeptin antagonists provides a valuable tool for investigating the physiological and pathophysiological roles of kisspeptin in the regulation of reproduction and could offer a unique therapeutic agent for treating hormone-dependent disorders of reproduction, including precocious puberty, endometriosis, and metastatic prostate cancer.

Alternative Li-Ion Battery Electrode Based on Self-Organized Titania Nanotubes

Abstract: We investigate the fabrication of an alternative electrode for lithium-ion batteries. The active material consists of self-organized TiO2 nanotube layers prepared by a simple anodization process. The performances of this type of nanostructured electrode are studied by the combination of structural techniques (Scanning electron microscopy and X-ray diffraction) and electrochemical tests. The discharge/charge properties and cycling performance characteristics are studied for both amorphous and crystalline titania nanotubes. With a maximum areal capacity of 77 μA h cm−2, a good capacity retention up to 90% over 50 cycles, nanotubular TiO2 is a promising electrode for rechargeable Li-ion microbatteries.

Direct effect of phosphorus on PTH secretion from whole rat parathyroid glands in vitro

Abstract: Phosphorus retention is an important factor in the development of hyperparathyroidism secondary to renal failure. In vivo manipulation of phosphorus is associated with changes in serum calcium and calcitriol levels which in turn can modify parathyroid hormone synthesis and secretion. The present in vitro study evaluates whether high extracellular phosphorus has a direct effect on parathyroid hormone secretion. Fresh rat parathyroid glands were incubated in a media with phosphorus concentrations of 1, 2, 3, and 4 mM and subsequently exposed to calcium levels ranging from 0.4 to 1.35 mM. In 1.25 mM calcium, the parathyroid hormone secretion rate was similar in 1 and 2 mM phosphorus; however, a phosphorus concentration of 3 and 4 mM produced a 3- and 4-fold increase in the parathyroid hormone secretion, respectively, as compared with 1 mM phosphorus. While in 1 or 2 mM phosphorus an increase in calcium from 0.6 to 1.35 mM reduced parathyroid hormone secretion to 37%, in 4 mM phosphorus the same increase in calcium only inhibited parathyroid hormone secretion to 75%. Furthermore, the addition of arachidonic acid 20 μM, a substrate for inhibitory intracellular signal pathway, to the 4 mM phosphorus-1.35 mM calcium incubation media reduced the parathyroid hormone secretion to 34.5% (p < 0.05). In conclusion, our results indicate that in vitro, high phosphorus directly increases parathyroid hormone secretion. (J Bone Miner Res 1996;11:970-976)

The emotional impact on victims of traditional bullying and cyberbullying: A study of Spanish adolescents.

Abstract: We examine the emotional impact caused to victims of bullying in its traditional form, both directly and indirectly, as well as bullying inflicted by use of new technologies such as mobile phones and the Internet. A sample of 1,671 adolescents and young people responded to a questionnaire which asked if they had been victims of various forms of bullying, as well as the emotions this caused. The results show that although traditional bullying affected significantly more young people than cyberbullying, the latter affected one in ten adolescents. Analysis of the emotions caused showed that traditional bullying produced a wide variety of impacts, with the victims being divided into five different emotional categories, while indirect bullying and cyberbullying presented a narrower variety of results with the victims being classifiable into just two groups: Those who said that they had not been emotionally affected and those who simultaneously suffered from a wide variety of negative emotions. The influence of age, gender, and severity on each emotional category is also analyzed.

Immunosenescence and vaccine failure in the elderly

Abstract: An age-related decline in immune responses in the elderly results in greater susceptibility to infection and reduced responses to vaccination. This decline in immune function affects both innate and adaptive immune systems. A meeting of experts in immunology and gerontology in Paris, France, in April 2008, considered current understanding of immunosenescence and its clinical consequences. Essential features of immunosenescence include: reduced natural killer cell cytotoxicity on a per cell basis; reduced number and function of dendritic cells in blood; decreased pools of naive T and B cells; and increases in the number of memory and effector T and B cells. In particular, an accumulation of late differentiated effector T cells, commonly associated with cytomegalovirus infection, contributes to a decline in the capacity of the adaptive immune system to respond to novel antigens. Consequently, vaccine responsiveness is compromised in the elderly, especially frail patients. Strategies to address the effects of immunosenescence include ensuring that seroprotective antibody levels against preventable infectious diseases are maintained throughout adulthood, and improving diet and exercise to address the effects of frailty. New vaccines are being developed, such as intradermal and high-dose vaccines for influenza, to improve the efficacy of immunization in the elderly. In the future, the development and use of markers of immunosenescence to identify patients who may have impaired responses to vaccination, as well as the use of end-points other than antibody titers to assess vaccine efficacy, may help to reduce morbidity and mortality due to infections in the elderly.

IL-17-producing CD8+ T lymphocytes from psoriasis skin plaques are cytotoxic effector cells that secrete Th17-related cytokines

Abstract: IL-17-producing CD4+ T lymphocytes (Th17) are currently considered relevant participants in the pathogenesis of psoriasis skin lesions. However, little is known about the potential role of IL-17-producing CD8+ T cells, which are also present at the psoriatic plaque. We have addressed the functional characterization of this CD8+ subtype of T lymphocytes from psoriasis patients. Our results show that CD8+IL-17+ cells from psoriasis-inflamed skin tissue produce TNF-alpha and IFN-gamma (Th1-related cytokines) as well as IL-17, IL-21, and IL-22 (Th17-related cytokines) efficiently. A significant up-regulation of the RORC transcription factor is also observed. These cells are refractory to Tregs but show a proliferative response to anti-CD3/CD28 stimulation that is enhanced by IL-12 and IL-15. Blocking of TNF-alpha activity inhibits TCR-mediated activation and IL-17 production. CD8+IL-17+ T cells are cytotoxic cells that display TCR/CD3-mediated cytotoxic abilities to kill target cells. Thus, CD8+IL-17+ T cells share some key features with Th17 cells and exhibit remarkable differential abilities attributable to the CD8+ lineage of T lymphocytes, adding new insights into the functional resources of IL-17-producing cells from human epidermis that could be of potential interest to our understanding of the pathogenesis of psoriasis.

Tuberculosis after Solid-Organ Transplant: Incidence, Risk Factors, and Clinical Characteristics in the RESITRA (Spanish Network of Infection in Transplantation) Cohort

Abstract: (95% confidence interval (CI), 317-783), which was higher than that in the general population in Spain (18.9 cases per 10 5 inhabitants per year; relative risk (RR), 26.6). The highest incidence (2072 cases per 10 5 patients per year; 95% CI, 565-5306) was observed among lung transplant recipients (RR, 73.3). Of the TB cases, 95% occurred within the first year after transplant, and 76% were pulmonary forms. Crude mortality was 19.0%, and attributable mortality was 9.5%. Multivariate analysis identified recipient age (RR, 1.05; 95% CI, 1.0-1.1) and receipt of a lung transplant (RR, 5.6; 95%, 1.9-16.9) as independent risk factors. Conclusions. TB incidence is increased among SOT recipients. The risk factors identified were age and receipt of a lung transplant. TB-attributable mortality (9.5%) is still high.

Soil management effects on runoff, erosion and soil properties in an olive grove of Southern Spain

Abstract: Rainfall, runoff and soil loss from 6 m × 12 m plots were recorded during 7 years (2000–2006) in an experiment in which three different soil management systems were compared in a young olive grove installed on a heavy clay soil, near Cordoba, Southern Spain. The no-tillage (NT) system, kept weed-free with herbicides, had both the largest soil loss (6.9 t ha−1 year−1) and the highest average annual runoff coefficient (11.9%). By contrast, a cover crop (CC) of barley, reduced the soil losses to 0.8 t ha−1 year−1 and the average annual runoff coefficient to 1.2%. Conventional tillage (CT), had intermediate values of soil loss (2.9 t ha−1 year−1) and an average runoff coefficient of 3.1%. The different treatments were established 4 years after planting the olive trees, and a significant decrease in soil and runoff losses was observed with time as the olive trees grew and their canopies developed. Measurements at the end of the experiment showed a significant improvement in the topsoil properties of the CC treatment as compared to CT and NT. The soil under NT presented a significant degradation with respect to traditional CT management. Organic matter values were 2.0, 1.4 and 1.0%, and stability in water of macroaggregates was 0.452, 0.418 and 0.258 kg kg−1 for CC, CT and NT, respectively. These results indicate that the use of a cover crop can be a simple, feasible soil and water conservation practice in olive groves on rolling lands in the region. A key factor in its practical use is to establish it early enough to protect the soil in the critical initial years of the grove, when most of the soil is unprotected by the small olive canopy.

Critical roles of kisspeptins in female puberty and preovulatory gonadotropin surges as revealed by a novel antagonist.

Abstract: Kisspeptins (Kp) have recently emerged as master regulators of the reproductive axis and among the most potent elicitors of GnRH-gonadotropin secretion. Despite their paramount importance in reproductive physiology and their potential therapeutic implications, development of Kp antagonists has remained elusive, and only recently has the first compound with the ability to block Kp actions in vitro and in vivo, namely p234, been reported. However, previous in vivo studies all used acute central injections, whereas characterization of the effects of the antagonist after continuous or systemic administration, which poses pharmacological challenges, is still pending. We report herein a comprehensive series of analyses on the impact of continuous intracerebroventricular infusion of p234 on puberty onset and the preovulatory surge of gonadotropins in the female rat. In addition, the effects of systemic (ip) administration of a tagged p234-penetratin, with a predicted higher permeability at the blood-brain barrier, on Kp-10 induced gonadotropin secretion were evaluated. Central infusion of p234 to pubertal females delayed vaginal opening and decreased uterine and ovarian weights at the expected time of puberty, without affecting body weight. Likewise, chronic intracerebroventricular administration of p234 for 4 d prevented the preovulatory surges of LH and FSH. In addition, systemic (ip) administration of p234-penetratin significantly attenuated acute LH and FSH responses to Kp-10, either after intracerebroventricular or ip injection of Kp. Our data document the validity of p234 for antagonizing Kp actions in vivo and provide direct experimental evidence for the important role of Kp signaling in the key events of female reproduction, such as puberty onset and the preovulatory surge of gonadotropins.

Repair and tolerance of oxidative DNA damage in plants.

Abstract: DNA damage caused by exposure to reactive oxygen species is one of the primary causes of DNA decay in most organisms. In plants, endogenous reactive oxygen species (ROS) are generated not only by respiration and photosynthesis, but also by active responses to certain environmental challenges, such as pathogen attack. Significant extracellular sources of activated oxygen include air pollutants such as ozone and oxidative effects of UV light and low-level ionizing radiation. Plants are well equipped to cope with oxidative damage to cellular macromolecules, including DNA. Oxidative attack on DNA generates both altered bases and damaged sugar residues that undergo fragmentation and lead to strand breaks. Recent advances in the study of DNA repair in higher plants show that they use mechanisms similar to those present in other eukaryotes to remove and/or tolerate oxidized bases and other oxidative DNA lesions. Therefore, plants represent a valuable model system for the study of DNA oxidative repair processes in eukaryotic cells.

The Mammalian Target of Rapamycin as Novel Central Regulator of Puberty Onset via Modulation of Hypothalamic Kiss1 System

Abstract: The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that operates as sensor of cellular energy status and effector for its coupling to cell growth and proliferation. At the hypothalamic arcuate nucleus, mTOR signaling has been recently proposed as transducer for leptin effects on energy homeostasis and food intake. However, whether central mTOR also participates in metabolic regulation of fertility remains unexplored. We provide herein evidence for the involvement of mTOR in the control of puberty onset and LH secretion, likely via modulation of hypothalamic expression of Kiss1. Acute activation of mTOR by l-leucine stimulated LH secretion in pubertal female rats, whereas chronic l-leucine infusion partially rescued the state of hypogonadotropism induced by food restriction. Conversely, blockade of central mTOR signaling by rapamycin caused inhibition of the gonadotropic axis at puberty, with significantly delayed vaginal opening, decreased LH and estradiol levels, and ovarian and uterine atrophy. Inactivation of mTOR also blunted the positive effects of leptin on puberty onset in food-restricted females. Yet the GnRH/LH system retained their ability to respond to ovariectomy and kisspeptin-10 after sustained blockade of mTOR, ruling out the possibility of unspecific disruption of GnRH function by rapamycin. Finally, mTOR inactivation evoked a significant decrease of Kiss1 expression at the hypothalamus, with dramatic suppression of Kiss1 mRNA levels at the arcuate nucleus. Altogether our results unveil the role of central mTOR signaling in the control of puberty onset and gonadotropin secretion, a phenomenon that involves the regulation of Kiss1 and may contribute to the functional coupling between energy balance and gonadal activation and function.

The influence of cover crops and tillage on water and sediment yield, and on nutrient, and organic matter losses in an olive orchard on a sandy loam soil

Abstract: Is the cover crop practice suitable for soil and water conservation in olive tree cropping? Rainfall, runoff, sediments, nutrient and organic carbon losses from 8 x 60 m plots were measured during four hydrological years (2002-2007) in a field trial, in which two different soil management systems were used to confirm this hypothesis: a cover crop (CC), and conventional tillage (CT). The plots were located in a private olive tree farm on a sandy-loam soil, near Seville, southern Spain. The cover crop, as compared to conventional tillage, efficiently reduced runoff and sediment yield down to tolerable levels, 5.68% of the rainfall being converted to runoff, and the soil loss reaching 0.04 kg m ―2 year ―1 , as the average of four years. Additionally, in the cover crop treatment, the values of the nutrient export either dissolved in the runoff water or adsorbed in the sediment, were lower than the analogous values of the conventional tillage treatment: 0.631 and 0.065 kg m- 2 year ―1 of organic carbon and nitrogen, respectively, 0.175 and 0.0333 kg m ―2 year ―1 of soluble K and P, respectively, and 0.010 and 0.002 kg m ―2 year ―1 of available K and P, respectively. The adoption of a cover crop as a soil management practice can be a feasible way to reach sustainability in many olive-cropped soils of southern Spain, although this method is not always easy to implement due to technical problems such as seed selection, its maintenance, and the choice of the correct killing date to avoid water competition. These difficulties could explain the slow rate of its adoption by many farmers. Further exploration of these aspects is required, as well as a specific agricultural extension campaign.