153 research outputs found

    The Self-Seeding of Anthemis arvensis L. for Cover Crop in Olive Groves under Intense Rabbit Grazing

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    Cover crops can be an effective means to protect soil and reduce risks of erosion in olive groves. However, for this protection to be significant, the vegetation must attain a significant amount of ground cover, which is estimated to be at least 30% during the rainy season. In olive groves on degraded soils, which occupy large surface areas in the olive-growing areas of the Mediterranean region, the establishment of cover crops may be an arduous challenge, particularly in areas with a high density of rabbits. In this study, we have selected two olive orchards with scarce natural vegetation located in Andalusia (southern Spain), in which rabbit populations intensively forage the cover crops, to test whether the self-seeding of an unpalatable species corn chamomile (Anthemis arvensis L.; A. arvensis for short) could achieve sufficient coverage for soil protection, in the year following that in which the broadcast-seeding was carried out for the implementation of cover crops. The hand broadcast-seeding of A. arvensis was carried out on sixteen elementary plots in the lanes of the two olive orchards in the autumn of 2015, and seed germination in the subsequent self-seeding took place in the autumn of 2016. The plant height and A. arvensis ground cover in these plots were measured throughout the two growth cycles, and aerial biomass was measured at maturity. The results showed that there were no significant differences in the maximum plant height between the two growth cycles (mean ± SD of 21.2 ± 1.6 cm), while the ground cover was significantly greater in the case of self-seeding, especially during the winter (37.2 ± 8.1 and 9.3 ± 6.7% for self-seeding and broadcast-seeding, respectively), and aerial biomass at maturity had more than doubled (99.7 and 43.9 g m−2, respectively). These data suggest that this unpalatable species could establish an effective herbaceous cover by means of self-seeding in olive groves on degraded soils that are being overgrazed owing to the high pressure of rabbits. Despite the poor establishment in the broadcast-seeding year, our findings indicate that A. arvensis might be an alternative cover crop that could help the sustainability of these threatened olive groves. Its high seed production (2000 to 4000 seeds per plant), and an early emergence just after the first autumn rains, should result in an increased ground cover by A. arvensis during the rainy season in the subsequent years of self-seeding. This, therefore, could contribute to soil conservation, in addition to providing other benefits of increased biodiversity and improvement for agricultural landscapes

    Sparse Givens resolution of large system of linear equations: applications to image reconstruction

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    In medicine, computed tomographic images are reconstructed from a large number of measurements of X-ray transmission through the patient (projection data). The mathematical model used to describe a computed tomography device is a large system of linear equations of the form AX=B. In this paper we propose the QR decomposition as a direct method to solve the linear system. QR decomposition can be a large computational procedure. However, once it has been calculated for a specific system, matrices Q and R are stored and used for any acquired projection on that system. Implementation of the QR decomposition in order to take more advantage of the sparsity of the system matrix is discussed.This work is partially supported by Generalitat Valenciana GVPRE/2008/303 and the Spanish M.E.C. grant MTM2009-08587.Rodríguez Álvarez, MJ.; Sánchez, F.; Soriano Asensi, A.; Iborra Carreres, A. (2010). Sparse Givens resolution of large system of linear equations: applications to image reconstruction. Mathematical and Computer Modelling. 52(7-8):1258-1264. https://doi.org/10.1016/j.mcm.2010.03.01612581264527-

    Competitividad, cooperación e interacción estratégica. Un experimento oligopolístico en el aula

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    We run a classroom experiment on oligopoly with students enrolled on basic and medium level microeconomics courses. Students compete in a symmetric quantity setting environment. The experiment runs over an entire academic semester and is divided into 20 one-week rounds. We want to explore whether the effect of knowledge and social interaction between players modifies the cooperative and competitive behavior observed in similar experiments run in a lab. Our hypothesis is that players are socially influenced. Hence, individuals adjust behavior in a dynamic way aimed at maximizing profits, but also according to social pressures. Overall, we obtain different learning processes across academic levels and also slightly different behavior from that predicted by economic theory. We argue that students’ utility function depends not only on profit levels but also on social relationships. Moreover, we believe that the effect of reputation plays an important role in our framework.Hemos llevado a cabo un experimento oligopolístico en el aula con estudiantes pertenecientes a los niveles básico y medio de la asignatura de microeconomía. Los estudiantes compitieron en un mercado donde todos tenían la misma función de costes ofreciendo cantidades de un bien en cada ronda. El experimento tuvo lugar durante un semestre académico completo y fue dividido en 20 rondas de una semana. Se quiere investigar si el efecto del aprendizaje y de la interacción social entre los jugadores modifica el comportamiento competitivo y cooperativo observado en experimentos similares llevados a cabo en un laboratorio. Nuestra hipótesis es que los jugadores están socialmente influenciados. Así pues, los individuos adecúan su comportamiento dinámicamente con el objetivo de maximizar beneficios pero también en concordancia con las presiones sociales. En general, se han observado diferentes procesos de aprendizaje por niveles académicos así como pequeñas diferencias de comportamiento con respecto a las pronosticadas por la teoría económica. Argumentamos que la función de utilidad de los estudiantes depende no sólo de los niveles de beneficio alcanzados sino también de las relaciones sociales. Más aún, pensamos que la reputación desempeña un papel relevante en el experimento de mercado que se ha llevado a cabo

    Quadruplex Ligands in Cancer Therapy

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    Nucleic acids can adopt alternative secondary conformations including four-stranded structures known as quadruplexes. To date, quadruplexes have been demonstrated to exist both in human chromatin DNA and RNA. In particular, quadruplexes are found in guanine-rich sequences constituting G-quadruplexes, and in cytosine-rich sequences forming i-Motifs as a counterpart. Quadruplexes are associated with key biological processes ranging from transcription and translation of several oncogenes and tumor suppressors to telomeres maintenance and genome instability. In this context, quadruplexes have prompted investigations on their possible role in cancer biology and the evaluation of small-molecule ligands as potential therapeutic agents. This review aims to provide an updated close-up view of the literature on quadruplex ligands in cancer therapy, by grouping together ligands for DNA and RNA G-quadruplexes and DNA i-Motifs

    Intense precipitation events in the Central Range of the Iberian Peninsula

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    Intense orographic precipitation associated with the Central Range was analysed using data of maximum accumulated precipitation in 24 h, occurring between 1958 and 2010. The 18 selected episodes were associated with a southwesterly tropospheric flow, a low-level jet, and high moisture flux at low levels. The observed moisture flux was higher than 100 (m g(s kg)−1) and the dry and wet Froude numbers were greater than 1. The selected area to study this synoptic situation was Gredos, broad and high range, which is located in the eastern part of the Central Range and generates a leeward “orographic shadow”. The effect of the Central Range on the spatial distribution of precipitation on the Iberian Peninsula plateau results in a sharp increase in precipitation in the south of the Central Range, followed by a decrease to the north of this range

    Proyecto de guía para la rehabilitación sísmica de edificios e infraestructuras existentes en Andalucía

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    Los terremotos siguen provocando numerosas víctimas en España pese a contar con una normativa específica desde 1962. La aceleración sísmica del terremoto acaecido en Lorca en 2011 superó el doble de la prevista en la actual NCSE-02. Sin embargo, la principal causa de los daños no fue consecuencia del colapso estructural, sino de deficiencias constructivas. La actual crisis económica sugiere que el parque edificado va a tener una vida útil muy superior a la prevista. Por tanto, con objeto de evitar futuras pérdidas humanas y disminuir daños tras la acción de un terremoto, se está realizando un Protocolo de Actuación para edificios e infraestructuras existentes que contará con dos partes: “clasificación de daños e intervenciones inmediatas” y “procedimientos de cálculo y soluciones constructivas para mejorar el comportamiento sísmico”. La primera parte de este Protocolo irá implementada con una aplicación informática que realizará un Informe previo sobre el grado de afección del edificio, acompañado de fotografías, croquis y una descripción de daños. La segunda parte propondrá coeficientes de seguridad, sistemas de comprobación y detalles constructivos para verificar y aumentar la seguridad de los edificios frente a sismo

    Assessment of Paraspinal Muscle Atrophy Percentage after Minimally Invasive Transforaminal Lumbar Interbody Fusion and Unilateral Instrumentation Using a Novel Contralateral Intact Muscle-Controlled Model

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    Study DesignRetrospective comparative clinical study.PurposeThis study aimed to assess paraspinal muscle atrophy in patients who underwent minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) and unilateral pedicle screw fixation using a novel contralateral intact muscle-controlled model.Overview of LiteratureThe increased incidence of paravertebral lumbar muscle injuries after open techniques has raised the importance of implementing minimally invasive spine surgical techniques using tubular retractors and minimally invasive screw placement. The functional cross-sectional area (FCSA) represents the lean muscle mass; furthermore, FCSA is a useful marker of the contractile ability of a muscle following a spine surgery. However, the benefits of unilateral fixation and MI-TLIF on paraspinal muscles have not been defined.MethodsWe performed a retrospective imagenological review on eleven patients who underwent unilateral MI-TLIF and unilateral transpedicular screw lumbar placement. FCSAs of the multifidus and erector spinae were measured 1 year after surgery at adjacent levels and were compared to the contralateral intact muscles. Measurement differences between the surgical and nonsurgical sites were compared. The interobserver reliability was calculated using an intraclass correlation coefficient.ResultsThe mean FCSA at the surgical site was 20.97±5.07 cm2 at the superior level and 8.89±2.87 cm2 at the inferior level. The mean FCSA at the contralateral nonsurgical site was 20.15±5.95 cm2 at the superior level and 9.20±2.66 cm2 at the inferior level was. The superior and inferior FCSA measurements showed no significant difference between the surgical and nonsurgical sites (p=0.5, p=0.922, respectively).ConclusionsUsing a mini-open tubular approach through the sulcus between the longissimus and iliocostalis, MI-TLIF and unilateral pedicle screw instrumentation produced minimal paraspinal muscle damage at the superior and inferior adjacent levels

    Assessment of Body Composition as an Indicator of Early Peripheral Parenteral Nutrition Therapy in Patients Undergoing Colorectal Cancer Surgery in an Enhanced Recovery Program

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    Background: A poor body composition (BC) has been identified as a risk factor for patients with colorectal cancer (CRC). This study was performed to assess the effect of early peripheral parenteral nutrition (PPN) on BC in patients undergoing CCR surgery within an enhanced recovery program. Methods: Patients with normal nutritional status were prospectively included between October 2016 and September 2019, randomized into two groups (PPN with periOlimel N4-E versus conventional fluid therapy) and subsequently classified according to their preoperative CT scan into high- or low-risk BC groups. Postoperative complications and length of hospital stay (LOS) were assessed. Results: Of the 156 patients analyzed, 88 patients (56.4%) were classified as having high-risk BC according to CT measurements. PPN led to a 15.4% reduction in postoperative complications in high-risk vs. 1.7% in low-risk BC patients. In the multivariate analysis, high-risk BC was related to an OR (95% CI) of 2 (p = 0.044) of presenting complications and of 1.9 (p = 0.066) for major complications, and was associated with an increase in LOS of 3.6 days (p = 0.039). Conclusions: The measurement of patients’ BC can allow for the identification of target patients where PPN has been proven to be an effective tool to improve postoperative outcomes

    Gallic Acid: A Natural Phenolic Compound Exerting Antitumoral Activities in Colorectal Cancer via Interaction with G-Quadruplexes

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    Natural phenolic compounds have gained momentum for the prevention and treatment of cancer, but their antitumoral mechanism of action is not yet well understood. In the present study, we screened the antitumoral potential of several phenolic compounds in a cellular model of colorectal cancer (CRC).We selected gallic acid (GA) as a candidate in terms of potency and selectivity and extensively evaluated its biological activity. We report on the role of GA as a ligand of DNA G-quadruplexes (G4s), explaining several of its antitumoral effects, including the transcriptional inhibition of ribosomal and CMYC genes. In addition, GA shared with other established G4 ligands some effects such as cell cycle arrest, nucleolar stress, and induction of DNA damage. We further confirmed the antitumoral and G4-stabilizing properties of GA using a xenograft model of CRC. Finally, we succinctly demonstrate that GA could be explored as a therapeutic agent in a patient cohort with CRC. Our work reveals that GA, a natural bioactive compound present in the diet, affects gene expression by interaction with G4s both in vitro and in vivo and paves the way towards G4s targeting with phenolic compounds.Instituto de Salud Carlos IIIEuropean Commission PI21/00497 AC18/00008Next generation EU, Plan de Recuperacion Transformacion y Resiliencia, Agencia Estatal de Investigacion PLEC2021-008094Ministerio de Ciencia e Innovacion from Government of Spain PID2019-104416RB-I00 PID2020-120481RB-I00Ministerio de Universidades from Government of Spain FPU16/05822 FPU17/05413 FPU20/03952University of Almeria FPI-20110

    Simultaneous Disinfection and Organic Microcontaminant Removal by UVC-LED-Driven Advanced Oxidation Processes

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    This work presents the comparison of four advanced oxidation processes driven by UVC-LED radiation (278 nm—2 W/m2) for simultaneous bacteria inactivation (Escherichia coli—106 CFU/mL) and microcontaminant removal (imidacloprid—50 µg/L) in simulated wastewater secondary effluent. To this end, the activation of H2O2 and S2O82− as precursors of HO• and SO4•−, respectively, by UVC-LED and UVC-LED/Fe3+–NTA (ferric nitrilotriacetate at 0.1 mM) has been studied at different oxidant concentrations. For the purpose of comparison, conventional chlorination was used as the baseline along with bacterial regrowth 24 h after treatment. Disinfection was achieved within the first 30 min in all of the processes, mainly due to the bactericidal effect of UVC-LED radiation. UVC-LED/H2O2 did not substantially affect imidacloprid removal due to the low HO• generation by UVC irradiation at 278 nm, while more than 80% imidacloprid removal was achieved by the UVC-LED/S2O82−, UVC-LED/Fe3+–NTA/S2O82−, and UVC-LED/Fe3+–NTA/H2O2 processes. The most efficient concentration of both oxidants for the simultaneous disinfection and microcontaminant removal was 1.47 mM. Chlorination was the most effective treatment for bacterial inactivation without imidacloprid removal. These findings are relevant for scaling up UVC-LED photoreactors for tertiary wastewater treatment aimed at removing bacteria and microcontaminants
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