204 research outputs found

    Kinetic study of the methanogenic step of a two-stage anaerobic digestion process treating olive mill solid residue

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    5 páginas, 4 figuras, 1 tabla.A kinetic study of the methanogenic step of a two-stage anaerobic digestion process treating two-phase olive oil mill solid residue (OMSR) was conducted at mesophilic temperature (35 °C). The anaerobic digestion of OMSR was carried out in two different steps. After a hydrolytic–acidogenic stage, working at an organic loading rate (OLR) of 12.9 g COD L−1 day−1 (COD: chemical oxygen demand), the effluents or acidified OMSR obtained were employed for feeding a second or methanogenic step. For the methanogenic step, OLRs of between 0.8 and 22.0 g COD L−1 day−1 were studied (corresponding to hydraulic retention times (HRTs) of between 142.9 and 4.6 days). The substrate treated in the second phase (acidified OMSR) had a high total concentration in volatile fatty acids (14.5 g CH3COOH L−1) and a high percentage of acetic acid as the main methane precursor (57.5% of the total concentration). As a consequence of the first step a high stability in the methanogenic stage was achieved. A total chemical oxygen demand balance was developed over the methanogenic step. For this model two considerations were taken in account: (1) volumetric flow constant during the experiments (the volume of effluent that was taken from the methanogenic reactor every day was equal to the volume of acidified OMSR fed). (2) Constant concentration of methanogenic microorganisms during the experiments (the slow growing rate of the methanogenic microorganisms makes it possible for the concentration of microorganisms over the process to remain constant). The cellular maintenance coefficient (m) and methane yield coefficient (YG/S) were found to be 0.016 g COD removed g−1 VSS day−1 and 0.261 L CH4 g−1 COD removed, respectively.The authors wish to express their gratitude to the Spanish “Ministerio de Educacion y Ciencia” (Project REN 2001-0472/TECNO) and the FECYT for providing financial support.Peer reviewe

    Effect of Ultrasonic Pretreatment on Biomethane Potential of Two-Phase Olive Mill Solid Waste: Kinetic Approach and Process Performance

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    The effect of ultrasound (US) pretreatment on two-phase olive mil solid waste (OMSW) composition and subsequent anaerobic biodegradation was evaluated by chemical oxygen demand solubilization and biochemical methane potential (BMP) tests. OMSW was ultrasonically pretreated at a power of 200 W and frequency of 24 kHz for time periods of 20, 40, 60, 90, 120, and 180 minutes, corresponding to specific energies of 11367, 21121, 34072, 51284, 68557, and 106003 kJ/kg total solids, respectively. In order to evaluate the US pretreatment, a low, medium, and high exposure time, that is, 20, 90, and 180 min, were selected for BMP tests. Methane yields of 311±15, 393±14, and 370±20 mL CH4/g VSadded (VS: volatile solids) were obtained for 20, 90, and 180 minutes, respectively, while the untreated OMSW gave 373±4 mL CH4/g VSadded. From a kinetic point of view, the BMP tests showed a first exponential stage and a second sigmoidal stage. In the first stage, the kinetic constant obtained for US pretreated OMSW at 20 minutes was 46% higher than those achieved for the pretreated OMSW at 90 and 180 minutes and 48% higher than that for untreated OMSW. The maximum methane production rate achieved was 12% higher than that obtained for untreated OMSW

    Effect of Ultrasonic Pretreatment on Biomethane Potential of Two-Phase Olive Mill Solid Waste: Kinetic Approach and Process Performance

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    The effect of ultrasound (US) pretreatment on two-phase olive mil solid waste (OMSW) composition and subsequent anaerobic biodegradation was evaluated by chemical oxygen demand solubilization and biochemical methane potential (BMP) tests. OMSW was ultrasonically pretreated at a power of 200 W and frequency of 24 kHz for time periods of 20, 40, 60, 90, 120, and 180 minutes, corresponding to specific energies of 11367, 21121, 34072, 51284, 68557, and 106003 kJ/kg total solids, respectively. In order to evaluate the US pretreatment, a low, medium, and high exposure time, that is, 20, 90, and 180 min, were selected for BMP tests. Methane yields of 311±15, 393±14, and 370±20 mL CH 4 /g VS added (VS: volatile solids) were obtained for 20, 90, and 180 minutes, respectively, while the untreated OMSW gave 373 ± 4 mL CH 4 /g VS added . From a kinetic point of view, the BMP tests showed a first exponential stage and a second sigmoidal stage. In the first stage, the kinetic constant obtained for US pretreated OMSW at 20 minutes was 46% higher than those achieved for the pretreated OMSW at 90 and 180 minutes and 48% higher than that for untreated OMSW. The maximum methane production rate achieved was 12% higher than that obtained for untreated OMSW

    The development of selective stopping: qualitative and quantitative changes from childhood to early adulthood

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    Although progress has been made in elucidating the behavioral and neural development of global stopping across the lifespan, little is known about the development of selective stopping. This more complex form of inhibitory control is required in real-world situations where ongoing responses must be inhibited to certain stimuli but not others, and can be assessed in laboratory settings using a stimulus selective stopping task. Here we used this task to investigate the qualitative and quantitative developmental changes in selective stopping in a large-scale cross-sectional study with three different age groups (children, preadolescents, and young adults). We found that the ability to stop a response selectively to some stimuli (i.e., use a selective strategy) rather than non-selectively to all presented stimuli (i.e., use a global, non-selective strategy) is fully mature by early preadolescence, and remains stable afterwards at least until young adulthood. By contrast, the efficiency or speed of stopping (indexed by a shorter stop-signal reaction time or SSRT) continues to mature throughout adolescence until young adulthood, both for global and selective implementations of stopping. We also provide some preliminary findings regarding which other task variables beyond the strategy and SSRT predicted age group status. Premature responding (an index of “waiting impulsivity”) and post-ignore slowing (an index of cognitive control) were among the most relevant predictors in discriminating between developmental age groups. Although present results need to be confirmed and extended in longitudinal studies, they provide new insights into the development of a relevant form of inhibitory controlThis work was supported by grants PSI2017-84922-R (Ministerio de Economía y Competitividad (MINECO, Spain) and SI1/PJI/2019-00061 (Comunidad de Madrid, Spain; V PRICIT

    Enhanced thermoelectricity in metal−[60]fullerene−graphene molecular junctions

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    The thermoelectric properties of molecular junctions consisting of a metal Pt electrode contacting [60]fullerene derivatives covalently bound to a graphene electrode have been studied by using a conducting-probe atomic force microscope (c-AFM). The [60]fullerene derivatives are covalently linked to the graphene via two meta-connected phenyl rings, two para-connected phenyl rings, or a single phenyl ring. We find that the magnitude of the Seebeck coefficient is up to nine times larger than that of Au-C60-Pt molecular junctions. Moreover, the sign of the thermopower can be either positive or negative depending on the details of the binding geometry and on the local value of the Fermi energy. Our results demonstrate the potential of using graphene electrodes for controlling and enhancing the thermoelectric properties of molecular junctions and confirm the outstanding performance of [60]fullerene derivativesThis work has been supported by the European Commission through FP7 ITN MOLESCO (Project Number 606728), the (MAD2D-CM)-UCM1-MRR project and through the EC H2020 FET Open Project Grant Agreement Number 767187 “QuIET”. The authors acknowledge support from the Spanish Ministry of Science and Innovation MCIN (Projects PID2020-114653RB-I00, PID2020-115120GB-I00, Centro de Excelencia Severo Ochoa SEV-2016-0686). L.R.-G. acknowledges support from Spanish MECD (Grant No. FPU14/03368) and, with N.A., funding from the Education and Research Council of the Comunidad de Madrid and the European Social Fund (ref. PEJD-2019-POST/IND-16353

    Mixed-method tutoring support improves learning outcomes of veterinary students in basic subjects

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    P. 1-10Tutoring is a useful tool in the university teaching-learning binomial, although its development is impaired in large classes. Recent improvements in information and communication technologies have made tutoring possible via the Internet. The aim of this study was to evaluate the efficacy of mixed-method academic tutoring in two basic subjects in Veterinary Science studies at the University of León (Spain) to optimize the usefulness of tutoring support in the college environment. This quasi-experimental study was firstly carried out as a pilot study in a small group of tutored students of “Cytology and Histology” (CH) (47/186; 25.3%) and “Veterinary Pharmacology” (VP) (33/141; 23.4%) subjects, and was implemented in a large class of CH the next academic year (150 students) while comparing the results with those obtained in a previous tutorless course (162 students). Tutored students were given access to online questionnaires with electronic feedback on each subject. In addition to traditional tutoring carried out in both tutored and tutorless students, the pilot study included three sessions of face-to-face tutoring in order to monitor the progress of students. Its efficacy was assessed by monitoring students’ examination scores and attendance as well as a satisfaction survey. Online tutoring support, together with conventional teaching methods, may be a useful method to incorporate student-centered learning in basic subjects in Veterinary Science.S

    Guardian: Electronic System Aimed at the Protection of Mistreated and At-risk People

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    Ambient Intelligence (AmI), based on ubiquitous computing, represents the most promising approach between people and technology to solve the challenge of developing strategies that allow the early detection and prevention of problems in automated dependence environments. One of the most influenced areas by AmI-based systems will be security and, more specifically, the protection of people under risk situations, including cases of mistreatment or loss. This will contribute to improve important aspects of the quality of life of these people, specially their safety. This paper describes Guardian, an integral solution designed for improving the protection of mistreated and at-risk people

    Recurrent presence of the PLCG1 S345F mutation in nodal peripheral T-cell lymphomas

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    This work was supported by grants from Asociación Española contra el Cancer (AECC), Ministerio de Economía y Competitividad (MINECO) (SAF2013-47416-R), Instituto Salud Carlos III (ISCIII) – Fondos FEDER, MINECO-AES(RD012/0036/0060, PI10/00621, CP11/00018). RM is supported by the Fundación Conchita Rábago de la Fundación Jiménez Díaz, Madrid (Spain). JG-R is supported by a predoctoral grant from the Fundacion Investigacion Biomedica Puerta de Hierro. Salary support to SG is provided by ISCIII-FEDER (CP11/00018). MS-B is supported by a Miguel Servet contract from ISCIII-FEDER (CP11/00018). The Instituto de Investigación Marqués de Valdecilla (IDIVAL) is partly funded by the Sociedad para el Desarrollo Regional de Cantabria (SODERCAN)

    Chronic lymphocytic leukemia cells in lymph nodes show frequent NOTCH1 activation

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    Chronic lymphocytic leukemia (CLL) is the most common adult leukemia in the Western world. Pathogenic mechanisms involve multiple external events (such as microenvironmental and antigenic stimuli) and internal events (genetic and epigenetic alterations) that are associated with the transformation, progression and evolution of CLL. CLL is characterized by an accumulation of mature B cells in peripheral blood, bone marrow and lymphoid tissues. Extracellular stimuli play an important role in the development and maintenance of neoplastic cells. B-CLL cells proliferate and activate pathogenic signaling pathways in anatomical structures known as proliferation centers, which are usually more conspicuous in involved lymph nodes.1 Its clinical course is quite heterogeneous, whereby some patients progress rapidly and have short survival, whereas others have a more stable clinical course that may not need treatment for years.This work was supported by grants from the Ministerio de Economía y Competitividad (MINECO) (SAF2013-47416-R) Instituto de Salud Carlos III (ISCIII)- FEDER – MINECO- AES (CP11/00018, PI10/00621, RD012/0036/0060), and Asociación Española contra el Cancer (AECC). MS-B is supported by a Miguel Servet contract from ISCIII-FEDER (CP11/00018). Salary support to SG is provided by CP11/00018, from ISCIII-FEDER. JG-R is supported by a predoctoral grant from the Fundación Investigación Puerta de Hierro.S

    Evaluación de la sintomatología negativista desafiante en niños de seis a ocho años : concordancia entre padres y maestros

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    El objetivo principal de este estudio es conocer el grado de concordancia entre los informes proporcionados por padres y maestros acerca de la sintomatología negativista desafiante en niños en edad escolar (6-8 años). Además, se pretende analizar si la edad y el sexo del niño afectan el nivel de acuerdo entre informantes. Padres y maestros evaluaron a 702 niños y niñas de 25 escuelas de la Comarca de Osona, Barcelona (España), mediante el Child Sympton Inventory-4 (versión padres y maestros). Los resultados indican una concordancia muy baja, casi nula, entre las valoraciones de ambos informantes; además, las variables edad y sexo de los niños no representan una diferencia significativa en dichas valoraciones. Los padres tienden a evaluar más síntomas del Trastorno Negativista Desafiante como presentes, y a percibir con mayor intensidad su severidadThe main goal of this study is to determine the degree of agreement between the reports provided by parents and teachers about oppositional defiant symptoms in school children between the ages of 6 and 8 years. In addition, it attempts to determine whether children's age and sex affect the level of agreement between informants. Parents and teachers assessed 702 girls and boys at 25 schools in the Region of Osona, Barcelona (Spain) with the Child Symptom Inventory-4 (parents' and teachers' version). The results indicate a very low agreement -practically null-between the valuations of both informants; furthermore, no significant difference due to the variables age and sex of the children was observed in the above-mentioned valuations. The parents tended to appraise most of the symptoms of the Oppositional Defiant Disorder as present and to evaluate their severity as being more intens
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