345 research outputs found

    Effect of continued and regulated deficit irrigation on the productivity of four vegetable crops in open-field conditions in the Mediterranean area

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    Tesis por compendio[ES] La escasez de agua se está convirtiendo en un problema en zonas áridas y semiáridas del mundo, donde se localiza parte de la producción de los principales cultivos hortícolas, como en el área mediterránea. La sequía es uno de los principales factores limitantes en la agricultura y está afectando gravemente a la producción de cultivos hortícolas. La mejora de la productividad del agua en la agricultura puede lograrse mediante la utilización de determinadas estrategias. El riego deficitario consiste en el aporte de agua por debajo de las necesidades de riego (NR) de los cultivos, de manera que se produce una reducción de la evapotranspiración. Puede realizarse de manera continua o sostenida (RDS) o controlada (RDC). Con el riego deficitario se puede mejorar la eficiencia del uso del agua de riego, manteniendo el rendimiento, e incluso en ocasiones, podría mejorarse la calidad de la cosecha. En este estudio, realizado en el Centro Experimental Cajamar de Paiporta (Valencia) se evalúa el efecto del riego deficitario en cuatro de los principales cultivos hortícolas cultivados al aire libre, en el área mediterránea: coliflor, cebolla, pimiento y sandía. En la evaluación se ha analizado: crecimiento y estado hídrico de las plantas, rendimiento, eficiencia del uso del agua de riego, calidad de la producción y rentabilidad de los cultivos. En la primera campaña se ensayó el RDS, lo que permitió establecer las diferentes etapas de crecimiento de cada cultivo, que se utilizaron en las siguientes campañas en el RDC. En los cuatro cultivos, las plantas control (100% NR) han mostrado un adecuado estado hídrico, tanto en el contenido relativo de agua como en el índice de estabilidad de la membrana, mientras que las sometidas a un RDS severo, han mostrado los menores valores de ambos índices. El efecto negativo del riego deficitario sobre el rendimiento ha resultado menos importante en los cultivos de otoño-invierno que en los cultivos de primavera-verano, especialmente en la coliflor. El RDS del 50% NR ha reducido drásticamente el rendimiento comercial y, consecuentemente, los ingresos brutos, aunque haya supuesto una mejora en la eficiencia del uso del agua de riego para los cultivos de otoño-invierno. Del análisis individual de los cultivos se deduce que el rendimiento en pellas de coliflor obtenidas con RDS al 75% NR o RDC al 50% NR durante la fase juvenil, se ha mantenido en niveles similares al control, mejorando la eficiencia del uso del agua de riego. En cebolla, en caso de restricción hídrica severa, sería aconsejable aplicar RDS con el 75% NR o RDC al 50% NR durante la maduración del bulbo, ya que estas estrategias han disminuido ligeramente el rendimiento, mejorando la eficiencia del uso del agua de riego. En condiciones menos restrictivas, RDC al 75% NR durante la maduración del bulbo ha dado lugar a un rendimiento satisfactorio, con un aumento de la eficiencia del uso del agua de riego. En pimiento dulce italiano, la aplicación de RDC al 75% NR durante la recolección ha dado lugar a una reducción considerable del rendimiento, y por tanto, de los ingresos brutos, aunque con importantes ahorros de agua y con un incremento en el contenido de sólidos solubles y de compuestos fenólicos de los frutos. Acortando el ciclo de cultivo hasta principios de septiembre, cuando ya se ha cosechado la mayor parte del rendimiento comercial, se conseguiría un importante ahorro de agua y permitiría utilizar la parcela en otros cultivos. El RDS al 75% y al 50% NR, o RDC al 50% NR durante la cosecha han dado lugar a una alta incidencia de frutos afectados por blossom-end rot. En sandía puede recomendarse la aplicación de RDC, tanto al 75% como al 50% NR durante la maduración del fruto, ya que ha conducido a rendimientos comerciales aceptables. De manera general se puede afirmar que la aplicación de RDS y de RDC en los cuatro cultivos, no ha afectado de manera importante a la calidad de la producción,[CA] Resum L'escassesa d'aigua s'està convertint en un problema en zones àrides i semiàrides del món, on es localitza part de la producció dels principals cultius hortícoles, com és el cas de l'àrea mediterrània. La sequera és un dels principals factors limitants en l'agricultura i està afectant greument a la producció de cultius hortícoles. La millora de la productivitat de l'aigua en l'agricultura en general, i en l'horticultura en particular, es pot aconseguir mitjançant la utilització de determinades estratègies. El reg deficitari consisteix en l'aportació d'aigua per sota de les necessitats de reg (NR) dels cultius, de manera que es produeix una reducció de l'evapotranspiració. Es pot fer de manera contínua o sostinguda (RDS) o controlada (RDC). Amb el reg deficitari es pot millorar l'eficiència de l'ús de l'aigua de reg, mantenint el rendiment, i fins i tot de vegades, podria conduir a una millora de la qualitat de la collita. En aquest estudi, realitzat al Centre Experimental Cajamar de Paiporta (València, Espanya) s'avalua l'efecte del reg deficitari en quatre dels principals cultius hortícoles conreats a l'aire lliure, a l'àrea mediterrània: dos de cultiu de tardor-hivern (coliflor i ceba) i dues de cultiu primaveral-estival (pimentó i meló d'Alger). En l'avaluació s'han analitzat els següents paràmetres: creixement i estat hídric de les plantes, rendiment, eficiència de l'ús de l'aigua de reg, qualitat de la producció i rendibilitat dels cultius. A la primera campanya es va assajar el RDS, el que va permetre establir les diferents etapes de creixement de cada cultiu, que es van utilitzar en les següents campanyes en el RDC. En els quatre cultius, les plantes control (100% NR) han mostrat un adequat estat hídric, tant en el contingut relatiu d'aigua com en l'índex d'estabilitat de la membrana, mentre que les sotmeses a un RDS sever, han mostrat els menors valors d'ambdós índexs. L'efecte negatiu del reg deficitari sobre el rendiment ha resultat menys important en els cultius de tardor-hivern que en els cultius de primavera-estiu, especialment en la coliflor. El RDS del 50% NR ha reduït dràsticament el rendiment comercial i, conseqüentment, els ingressos bruts, encara que hagi suposat una millora en l'eficiència de l'ús de l'aigua de reg per als cultius de tardor-hivern. De l'anàlisi individual dels cultius es dedueix que el rendiment de coliflors obtingudes amb RDS al 75% NR o RDC al 50% NR durant la fase juvenil, s'ha mantingut en nivells similars al control, millorant l'eficiència de l'ús de l'aigua de reg. En ceba, en cas de restricció hídrica severa, seria aconsellable aplicar RDS amb el 75% NR o RDC al 50% NR durant la maduració del bulb, ja que aquestes estratègies han disminuït lleugerament el rendiment, millorant l'eficiència de l'ús de l'aigua de reg . En condicions menys restrictives, RDC al 75% NR durant la maduració del bulb ha donat lloc a un rendiment satisfactori, amb un augment de l'eficiència de l'ús de l'aigua de reg. En pimentó dolç italià, l'aplicació de RDC al 75% NR durant la recol·lecció ha donat lloc a una reducció considerable del rendiment, i per tant, dels ingressos bruts, encara que amb importants estalvis d'aigua i amb un increment en el contingut de sòlids solubles i de compostos fenòlics dels fruits. Retallant el cicle de cultiu fins a principis de setembre, quan ja s'ha collit la major part del rendiment comercial, s'aconseguiria un important estalvi d'aigua i permetria utilitzar la parcel·la en altres cultius. El RDS al 75% i al 50% NR, o RDC al 50% NR durant la collita han donat lloc a una alta incidència de fruits afectats per blossom-end rot. En meló d'Alger es pot recomanar l'aplicació de RDC, tant al 75% com al 50% NR durant la maduració del fruit, ja que ha conduït a rendiments comercials acceptables. De manera general es pot afirmar que l'aplicació de RDS i de RDC en els quatre cultius, no ha afectat de maner[EN] Water scarcity is becoming a critical problem in arid and semi-arid areas of the world, where part of the production of the main horticultural crops is located, as is the case of the Mediterranean area. Drought is one of the main limiting factors in agriculture and it is seriously affecting the production of horticultural crops. The improvement of water productivity in agriculture in general, and in horticulture in particular, can be achieved through the use of certain strategies. Deficit irrigation consists of the supply of water below the irrigation water requirements (IWR), so that there is a reduction in evapotranspiration. It can be done continuously (CDI) or regulated (RDI). With deficit irrigation, the irrigation water use efficiency can be improved, maintaining yield, and it could even lead to an improvement in the quality of the harvest. This study, carried out at the Cajamar in Paiporta Experimental Center (Valencia, Spain), analyzes the effect of deficit irrigation on four of the main cultivated horticultural crops, open field cultivated in the Mediterranean area: two of autumnal-winter crops (cauliflower and onion) and two spring-summer crops (pepper and watermelon). In the evaluation, the following parameters have been analyzed: plant growth and water status, yield, irrigation water use efficiency, quality of production and crop profitability. In the first season the CDI was tested, which allowed to establish the different growth stages for each crop, which were used in the following season for the RDI. In the four crops, the control plants (100% IWR) have shown an adequate water status, in terms of both relative water content and membrane stability index, while those subjected to a severe CDI, have shown the lowest values of both indexes. The negative effect of deficit irrigation on yield has been less important in autumn-winter crops than in spring-summer crops, especially in cauliflower. The CDI at 50% IWR has drastically reduced the marketable yield and, consequently, the gross revenue, although it has supposed an improvement in the irrigation water use efficiency for the autumn-winter crops. From the individual analysis of the crops, it can be stated that cauliflower yield obtained with CDI at 75% IWR or RDI at 50% IWR during the juvenile phase, has remained at levels similar to the control, improving the irrigation water use efficiency. In relation to onion, in case of severe water restriction, it would be advisable to apply CDI with 75% IWR or RDI at 50% IWR during bulb ripening, since these strategies have slightly decreased yield, improving the irrigation water use efficiency. In less restrictive conditions, RDI at 75% IWR during the bulb maturation has led to a satisfactory yield, with an increase in the irrigation water use efficiency. In Italian sweet pepper, the application of RDI to 75% IWR during the harvesting has resulted in a considerable reduction of the yield, and therefore, of the gross income, although with important water savings and increasing the fruit soluble solids and phenolic compounds content. By shortening the cultivation cycle until the beginning of September, when most of the marketable yield has already been harvested, significant water savings would be achieved, and the land could be used in other crops. CDI at 75% IWR and 50% IWR, or RDI at 50% IWR at harvesting have resulted in a high incidence of fruit affected by blossom-end rot. In watermelon the RDI application can be recommended, both 75% and 50% IWR, during the fruit ripening, since it has led to acceptable marketable yields. In general terms, it can be affirmed that the application of CDI and RDI in the four crops has not significantly affected the product quality, in terms of the analyzed parameters.My grateful thanks to the Cultural Affairs and Mission Sector, Egyptian Ministry of Higher Education for supporting me with a scholarship.Abdelkhalik, AGA. (2019). Effect of continued and regulated deficit irrigation on the productivity of four vegetable crops in open-field conditions in the Mediterranean area [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/129868Compendi

    Profiling movie downloaders in Egypt: Law awareness as an attitudinal factor

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    This study is aimed at determining the main antecedents of the intention to illegally download movies in Egypt. This study examined the role of law awareness in forming the attitude toward illegal downloading and the methods downloaders use to rationalize their act. A model was proposed based on the planned behavior, neutralization and deterrence theories. A sample of 384 Mass Communication students at Cairo University was surveyed. The findings showed that law awareness does not play a direct role in forming attitudes toward movie illegal downloading. Even though the more illegal downloaders were aware of the illegality of movie copyright infringement, the more they perceived the law as deterrent; they continued downloading movies. The results also indicated that perceived deterrence has no direct correlation with attitude. The results showed that downloaders with lower levels of law awareness needed to rationalize their piracy act, which may indicate that they are aware of the immorality of their act regardless of its illegality. In addition, limiting access to movies and failing to provide more legitimate venues may cause more favorable attitude toward the illegal downloading which may represent one of the very few choices left to movie fans. Furthermore, attitude was found to be the strongest determinant of illegal downloading intention. Moreover, the current findings showed that movie downloaders perceived movie piracy as an easy act. The fight against piracy should include non-downloaders also, since this study showed that the societal acceptance was another driving force for movie piracy

    Microcephalic osteodysplastic primordial dwarfism (MOPD) type I with severe anemia and MRI brain findings of MOPD type II

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    We report a 4 month old male, 4th in order of birth of healthy consanguineous Egyptian parents with typical characteristics of microcephalic osteodysplastic primordial dwarfism most probably belongs to type I (MOPD I). The patient had intrauterine growth retardation, sparse scalp hair, sparse eyebrows and eyelashes, high arched palate, micrognathia, low set ears, short neck, clenched fists, groove between thumb and palm of hand, arachnodactyly, flexion contractures of elbow and knee. He also had thin dry skin with marked decreased subcutaneous fat and prominent superficial veins over chest and abdomen and mild hypertrichosis over lower back and buttocks. However, the patient had severe anemia and MRI brain findings revealed global hypovolemic brain changes in the form of dilated ventricles and widened cortical sulci, multiple old vascular insults and aneurismal dilatation of right internal carotid artery (ICA) which are consistent with MOPD II

    THE ROLE OF ISLAMIC CULTURE COURSES IN MAINTAINING THE ISLAMIC IDENTITY: CASE STUDY OF FACULTY OF LANGUAGES AND TRANSLATION FEMALE STUDENTS AT KING KHALID UNIVERSITY

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    The present study is an interdisciplinary research that investigates the role of Islamic culture courses in maintaining the Islamic identity among the female students of the English department at King Khalid University. It is due to the significance of these courses that the researchers design this study to explore the extent to which the Islamic culture courses achieve the objectives envisaged by them. This study further explores the ability of these courses to confront the ideas of globalization and the new international order including the world’s economic, political, cultural and social ideologies. The study also investigates the need of such courses to enable the students of the English department to be prepared to study certain courses enrolled at the faculty of languages and translation (i.e. religious translation course). For this end, the students are requested to complete an online survey composed of closed-ended and open-ended questions on their perceptions about the Islamic culture courses and their significance. As such, the study adopts both quantitative and qualitative methods and ends up with suggesting certain recommendations towards improving the courses specifications and implementing the students’ special knowledge of the English language and culture in empowering them to present the disciplined Islamic concept and identity.

    Computed tomography independent quantitative determinants of CAD-RADS 4 versus CAD-RADS 3 for calcified coronary lesions

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    Purpose: An investigation of coronary computed tomography angiography (CCTA)-derived quantitative parameters to determine CAD-RADS 4 versus CAD-RADS 3 of coronary lesions with moderate to severe calcification. Material and methods: The study included 150 coronary lesions proven to have moderate or severe stenosis by invasive coronary angiography and showing moderate to severe calcification in CCTA. Various CCTA-quantitative parameters were correlated to the degree of stenosis (moderately versus severely stenosed lesions). Their sensitivity and specificity to detect severe stenosis (supposed to be corresponding to CAD-RADS 4) were examined at multiple cut-off points. Results: The calcification remodelling index (CRI) was the only statistically significant independent computed tomography angiography-derived predictor of severe stenosis versus moderate stenosis on multivariate regression analysis. The best cut-off value was ≤ 0.84, with 77.78% sensitivity and 86.46% specificity. Conclusions: From all quantitative-derived CCTA parameters, CRI ≤ 0.84 was the predictor with the highest diagnostic performance for severe versus moderate stenosis in moderately to severely calcified coronary lesions. Accordingly, CRI can help to determine CAD-RADS 4 versus CAD-RADS 3

    Approaches for the isolation and long-term expansion of pericytes from human and animal tissues.

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    Pericytes surround capillaries in every organ of the human body. They are also present around the vasa vasorum, the small blood vessels that supply the walls of larger arteries and veins. The clinical interest in pericytes is rapidly growing, with the recognition of their crucial roles in controlling vascular function and possible therapeutic applications in regenerative medicine. Nonetheless, discrepancies in methods used to define, isolate, and expand pericytes are common and may affect reproducibility. Separating pure pericyte preparations from the continuum of perivascular mesenchymal cells is challenging. Moreover, variations in functional behavior and antigenic phenotype in response to environmental stimuli make it difficult to formulate an unequivocal definition of bona fide pericytes. Very few attempts were made to develop pericytes as a clinical-grade product. Therefore, this review is devoted to appraising current methodologies’ pros and cons and proposing standardization and harmonization improvements. We highlight the importance of developing upgraded protocols to create therapeutic pericyte products according to the regulatory guidelines for clinical manufacturing. Finally, we describe how integrating RNA-seq techniques with single-cell spatial analysis, and functional assays may help realize the full potential of pericytes in health, disease, and tissue repair

    A quality assurance technique for the static multileaf collimator mode based on intrinsic base lines

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    AbstractThe inspection of the static leaf positions of Multileaf Collimator (MLC) devices is essential for safe radiotherapy deliveries in both static and dynamic modes. The purpose of this study was to develop a robust, accurate and generic algorithm to measure the individual static MLC leaf positions. This was performed by extracting leaf tip locations from the radiographic film image and measuring their relative distance from a reference line on the film. The reference line was created with a selected set of MLC leaf sides. The film scaling was created and verified using the physical leaf width. The average measured distance corresponds to a leaf width of 10 mm was 9.95 ± 0.09 mm. The estimated reproducibility of the leaf tips location was ±0.26 mm. The code accuracy was checked by intentionally positioning set of leaves with small errors (1 mm), and the detected deviations from the expected positions ranged from −0.25 mm and +0.32 mm. The algorithm includes two self testing functions in order to detect failures of leaf positioning due to poor film quality and to avoid the potential systematic errors attributable to the improper collimator setting. The code is promising to be more efficient with Gafchromic and Electronic Portal Imaging Device (EPID)

    Trichorhinophalangeal syndrome II, expanding the clinical spectrum

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    AbstractWe report a 4.5year old Egyptian male child, fourth in the order of birth of healthy remote consanguineous parents. He has typical facial as well as skeletal features of Trichorhinophalangeal syndrome (TRPS) II. The facial features included bilateral downward slanting palpebral fissures, bulbous nose, long filtrum, retromicrognathia, sparse hair in the scalp and thick eyebrows. The skeletal features included retarded bone age, cone shaped epiphyses of the phalanges and multiple exostoses. The patient has also growth retardation, moderate mental retardation and hyperlaxity of the right knee joint. However our patient has some features not reported in TRPS II patients. These included bilateral partial ptosis, long eye lashes, preauricular skin tag, short 2nd right finger, short metacarpals of both thumbs. So we have to expand the clinical spectrum. Karyotype demonstrated 46,XY,del 8(q23.3-q24.1)
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