3,636 research outputs found
Evolution of the spherical cavity radius generated around a subsurface emitter
The emitter discharge in subsurface drip irrigation can be affected by soil properties. A positive pressure develops at the emitter outlet where a spherical cavity is assumed to form. In steady-state conditions, the pressure in the soil relates to soil hydraulic 5 properties, the emitter discharge, and the cavity radius. This pressure in the soil is very sensitive to the cavity radius. In this paper, the development of the cavity around the emitter outlet was measured for various emitter discharges in laboratory tests carried out in containers with uniform loamy soils. A trend between soil pressure and emitter discharge was established that illustrates the performance of buried emitters in the 10 field. Its application to the prediction of water distribution in subsurface drip irrigation units and its effect on the estimation of irrigation performance is also show
Water distribution in laterals and units of subsurface drip irrigation. II: Field evaluation.
The performance of drip irrigation and subsurface drip irrigation (SDI) laterals has been compared. Two emitter models (one compensating and the other noncompensating) were assessed. Field tests were carried out with a pair of laterals working at the same inlet pressure. A procedure was developed that recorded head pressures at both lateral extremes and inlet flow during irrigation. Both models showed similar behavior and soil properties affected their discharge. On the other hand, the performance of a field SDI unit of compensating emitters was characterized by measuring pressures at different points and inlet flow. Finally, the distribution of water and soil pressure in the laterals and the unit were predicted and irrigation uniformity and soil pressure variability were also determined. Predictions agreed reasonably well with the experimental observations. Thus, the methodology proposed could be used to support the decision making for the design and management of SDI system
Job-search strategies of individuals at risk of poverty and social exclusion in Spain
In Spain, the issue of unemployment or precarious employment worsen with globalization, leading to an expansion of the so-called working poor in the labour market.According to previous literature, the economic poverty that is characteristic of this group may accompany poverty competency.In particular, the working poor resort to informal and poorly developed job-searchstrategies.This study addresses the job search methods used by people at risk of poverty and social exclusion. It provides evidence on the subject and serves as a basis for the adaptation of socio-labour intermediation programmes to this group.The hypothesis of this study is that people at high risk will predominantly use informal strategies that require a low level of job-searchs kills.A survey-based correlational study is conducted using a questionnaire completed by 279 people participating in socio-labourinter mediation programmes developed by the Action against Hunger Foundation(AaHF) in Spain.Information on poverty indicators and on job-search strategies is collected.Data are analysed through cluster analysis,which distinguish two groups of people at risk of poverty and social exclusion(high risk and low risk),followed by a comparison of means(t-test)with a subsequent calculation of effect size using Cohen’s d. Results show statistically significant differences with a medium effect size(between 0.45 and 0.50)for the typology of job-search strategies used,confirming the initial hypothesis.These results offer relevant information that should be considered when developing programmes aimed at improving social and labour issues for people at risk of poverty and social exclusion.Ministry of Economy and Competitiveness (MINECO- Government of Spain)European Regional Development Fund (ERDF-FEDER
Emitter discharge variability of subsurface drip irrigation in uniform soils: effect on water-application uniformity
Emitter discharge of subsurface drip irrigation (SDI) decreases as a result of the overpressure in the soil water at the discharge orifice. In this paper, the variation in dripper discharge in SDI laterals is studied. First, the emitter coefficient of flow variation CVq was measured in laboratory experiments with drippers of 2 and 4 L/h that were laid both on the soil and beneath it. Additionally, the soil pressure coefficient of variation CVhs was measured in buried emitters. Then, the irrigation uniformity was simulated in SDI and surface irrigation laterals under the same operating conditions and uniform soils; sandy and loamy. CVq was similar for the compensating models of both the surface and subsurface emitters. However, CVq decreased for the 2-L/h non-compensating model in the loamy soil. This shows a possible self-regulation of non-compensating emitter discharge in SDI, due to the interaction between effects of emitter discharge and soil pressure. This resulted in the irrigation uniformity of SDI non-compensating emitters to be greater than surface drip irrigation. The uniformity with pressure-compensating emitters would be similar in both cases, provided the overpressures in SDI are less than or equal to the compensation range lower limit
On the developmente of new viedeo stations to monitor meteorite-droppimg events over Spain
The
SPanish Meteor and Fireball Network
(SPMN) is an interdisciplinary project involving several universi-
ties and research centres with the
aim to study meteor and fireball
events occurring over Spain and the bordering countries [1].
Large fireballs can be the precursors of meteorite falls and, so,
the establishment of a network of
detection systems is very con-
venient in order to increase the chance of meteorite recovery by
tracking their atmospheric trajectories and predicting the corre-
sponding landing sites. To do this it is necessary to record the
luminous trail from at least two different locations
The afterglow photosynthetic luminescence
The afterglow (AG) photosynthetic luminescence is a long-lived chlorophyll fluorescence emitted from PSII after the illumination of photosynthetic materials by FR or white light and placed in darkness. The AG emission corresponds to the fraction of PSII centers in the S2/3QB non-radiative state immediately after pre-illumination, in which the arrival of an electron transferred from stroma along cyclic/chlororespiratory pathway(s) produces the S2/3QB− radiative state that emits luminescence. This emission can be optimally recorded by a linear temperature gradient as sharp thermoluminescence (TL) band peaking at about 45°C. The AG emission recorded by TL technique has been proposed as a simple non-invasive tool to investigate the chloroplast energetic state and some of its metabolism processes as cyclic transport of electrons around PSI, chlororespiration or photorespiration. On the other hand, this emission has demonstrated to be a useful probe to study the effect of various stress conditions in photosynthetic materials.Junta de Andalucía PAIDI BIO-022Ministerio de Economía, Industria y Competitividad BIO2015-64169-
Low-velocity cometary meteoroid streams encountering the earth: clues on the fragmentation of cometary aggregates and implications for interplanetary dust particles
Since 2005, the SPanish Fireball
and Meteor Network (SPMN) is continuously monitor-
ing meteor activity by using all-sky CCD and medium-
field video cameras up to +3 to +4 meteor limiting
magnitude [1,2]. One important goal of our network is
the study of the meteoroid physico-chemical properties
from multiple station data, together with meteor spec-
tra. It is well known that the ablation behavior of me-
teors in the Earth’s atmosphere shows photometric
patterns that are reflecting important properties of the
incoming meteoroids [3], but we are not yet fully un-
derstanding such patterns. Besides, we are also trying
to identify the main sources of large bolides to the
Earth. As a consequence of the SPMN monitoring ef-
fort, valuable trajectory and orbital data of meteors and
fireballs is being obtained [4-6]. During 2007 several
poorly-known meteoroid streams associated with com-
ets were crossed by the Earth. We describe here unex-
pected fireball activity, but focusing in low-velocity
cometary streams. Particularly, we describe some me-
teor outbursts and fireball events recorded by the
SPMN during 2006-2007 that would be important de-
livery sources of Interplanetary Dust Particles (IDPs).
We try to encourage setting up future IDP campaigns
for collecting cometary particles in the upper atmos-
phere. By knowing the most important and favourable
sources of cometary particles, and the dates of the en-
counters with dense dust trails, such missions would
be prepared in time for being successful
Restauración del Mausoleo de Sidi Bou Guertif, El Khorbat, Marruecos
[EN] This contribution tries to describe the research and intervention process that the authors have carried out for the conservation of the Sidi Bou Guertif Mausoleum. The methodological process has been based on the prior knowledge of the construction systems, as well as the conservation and recovery-reconstruction techniques used by the region’s master builders, practices that are respectful with the building and that are validated by their use for centuries. In addition, the project contemplated the involvement of young locals interested in learning about these jobs that unfortunately disappear, but are absolutely necessary to preserve this heritage at-risk.[ES] La presente contribución describe el proceso de investigación e intervención que los autores han seguido para la restauración del Mausoleo de Sidi Bou Guertif. El proceso metodológico se ha basado en el conocimiento previo de los sistemas constructivos, así como de las técnicas de conservación y recuperación-reconstrucción empleadas por los maestros de obras de la región, prácticas que son respetuosas con el edificio y que se encuentran validadas por su uso durante siglos. Además el proyecto contempló la incorporación de jóvenes locales interesados en conocer estos oficios que lamentablemente van desapareciendo, pero que son absolutamente necesarios para poder preservar este patrimonio en peligro.Proyecto ADSIDEO-Cooperación del Centro de Cooperación al Desarrollo de la Universitat Politècnica de ValènciaGil Piqueras, MT.; Rodríguez Navarro, P. (2019). Restoration of the Sidi Bou Guertif Marabout, El Khorbat, Morocco. Loggia, Arquitectura & Restauración. 0(32):60-73. https://doi.org/10.4995/loggia.2019.11899OJS6073032AAVV, 2005. Conservation manual for Earth Architecture Heritage in the pre-Saharan valleys of Morocco: CERKAS / UNESCO World Heritage Centre / CRATerre-EAG.ACHENZA, M. M., 2012. "Elements for the definition of good practices for the conservation and the restoration of the historical urban fabric of a Moroccan Pre-Saharan oasis" in Rammed Earth Conservation: Proceedings of the First International Conference on Rammed Earth Conservation, Restapia 2012, Valencia, Spain, 21-23 June 2012, eds. Camilla Mileto, Fernando Vegas, and Valentina Cristini, pp. 607-613. Boca Raton, FL: CRC Press. https://doi.org/10.1201/b15164-104GIL-PIQUERAS, T. and P. RODRÍGUEZ-NAVARRO. 2018. Hábitat y desarrollo en el Sur de Marruecos. El Khorbat en el Oasis del Ferkla: Argumentum, Lisboa (Portugal).ICHTER, J.P. and H.SASS, 1967. "Les Ksour du Tafilalt", in Revue africaine d'architecture et d'urbanisme n°5, Rabat.NIJST, A.L.M.T. et ali. 1973. Living on the edge of the Sahara. A study of traditional forms of habitation and types of settlement in Morocco: Ed.Government Publishing Office. The Hague.RODRÍGUEZ-NAVARRO, P., F. JUAN VIDAL and T. GIL-PIQUERAS, 2012. "Earth construction techniques in the northern High Atlas, Morocco", in Rammed Earth Conservation: Proceedings of the First International Conference on Rammed Earth Conservation, Restapia 2012, Valencia, Spain, 21-23 June 2012, eds. Camilla Mileto, Fernando Vegas, and Valentina Cristini, pp. 569-574. Boca Raton, FL: CRC Press. https://doi.org/10.1201/b15164-9
Universidad Nacional de Lomas de Zamora: el impacto de la comunicación con TIC's en la Enseñanza Superior (caso de redes sociales)
El nuevo contexto socio-tecnológico ha alcanzado el mundo académico creando nuevas formas de generar y transmitir conocimiento. Ha surgido la necesidad de replantear el binomio enseñanza-aprendizaje y utilizar nuevas tecnologías a fin de mejorar la inserción de los alumnos al ámbito universitario.
En este contexto, la tarea del docente comprende el diseño y la elaboración de entornos sociales virtuales interactivos, en los cuales el verdadero protagonista de los procesos formativos sea el estudiante. Frente a este desafío, nos proponemos explorar los factores clave para el diseño de un Modelo Académico de Gestión de la Comunicación y de la Información con soporte en la estructura de las Redes Sociales en la Facultad de Ingeniería de la Universidad Nacional de Lomas de Zamora (FI-UNLZ). A tal fin, analizaremos el tipo y nivel de participación de los alumnos en el desarrollo de actividades de trabajo colaborativo a través del uso de Redes Sociales con fines académicos.The new socio-technological context has reached the academic world creating new ways of generating and transmitting knowledge. The need to reformulate the teaching-learning pairing and to use the new technologies have emerged, in order to improve the students’ incorporation into the university ambit. In this context, the university professor’s task comprises the design and elaboration of interactive virtual social environment in which the real protagonist in the educational process is the student. Facing this challenge, we pose to explore the key factors for the design of an Academic Model of Communication and Information Management supported on the Social Networks structures of the Facultad de Ingeniería de la Universidad Nacional de Lomas de Zamora (FI-UNLZ). For this aim, we will analyse the type and level of students’ participation in the development of collaborative work through the use of Social Networks with academic purposes
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