Determinación absorciométrica de fósforo en plantas

p.127-130Se describen tres metodologías para la valoración de fósforo en vegetales. Al comparar los valores obtenidos de fósforo para cada técnica y observando la concordancia significativa entre los mismos se propone hacer una mineralización húmeda de la muestra y de terminar el contenido de fósforo mediante la medición espectrofotométrica del complejo amarillo de fosfovanadomolibdeno

Incidencia de la descarga de efluentes de un feedlot en la calidad de agua del Arroyo Morales Buenos Aires - Argentina

p.167-176En este trabajo se analizaron las variaciones que se producen en las concentraciones de N y P presentes en los efluentes de un feedlot al atravesar un canal de conducción de excretas y se estableció la influencia de su descarga en la calidad del agua de un arroyo de bajo caudal. Los resultados indicaron que este canal no retuvo eficientemente los nutrientes presentes en estos efluentes, estableciéndose un deterioro en la calidad de agua del arroyo que varía con la temperatura y a la altura hidrométrica del mismo

Supporting Team Reflexivity During the COVID-19 Lockdown: A Qualitative Study of Multi-Vision Groups In-Person and Online

Introduction: The professional self is often hindered by a lack of self-care and poor work-life balance, and cannot be considered an unlimited resource. Given this, the reflexive team is an important organizational tool for protecting workers’ well-being. The non-profit organization Maestri di Strada (MdS) (“Street Teachers”) conducts action research (AR) in the area of socio-education. The main tool used by the group to protect the well-being of its members is a guided reflexivity group, inspired by the Balint Group and termed the Multi-Vision Group (MG). In March 2020, because of the COVID-19 lockdown, the MdS team had to quickly revamp its working model, and MGs were held online for the first time. Aim: Through qualitative research that takes a longitudinal approach, the aim of this study is to evaluate the efficacy of the MG in supporting the team’s reflexivity in this new online format. Methods: This article considers MGs during two different time periods: pre-pandemic (T1) and early pandemic (T2). During T1, the MdS team met 18 times in person, while during T2 the team met 12 times through an online platform (always under the guidance of a psychotherapist). During all sessions in both time periods, a silent observer was present in the meetings, and they subsequently compiled narrative reports. The textual corpora of the reports were submitted for a Thematic Analysis of Elementary Contexts through T-Lab Plus, in order to examine the main content of the groups’ discourse. Results: The results (five clusters in T1; and five in T2) show that, during T2, the group devoted considerable time to experiences tied to the pandemic (T21: schools facing the pandemic crisis; T2.2: the pandemic: death, inner worlds, and thought resistance; T2.3: kids’ stories involving physical distancing and emotional proximity). The group also came up with innovative educational initiatives that defied the lockdown (T2.4: fieldwork: the delivery of “packages of food for thought”; T2.5: the MdS group: identity and separation). Based on these findings, the MG most likely contributed to the emergence of MdS as a “resilient community,” capable of absorbing the shock of the pandemic and realizing a fast recovery response

Interpreting Encoding and Decoding Models

Encoding and decoding models are widely used in systems, cognitive, and computational neuroscience to make sense of brain-activity data. However, the interpretation of their results requires care. Decoding models can help reveal whether particular information is present in a brain region in a format the decoder can exploit. Encoding models make comprehensive predictions about representational spaces. In the context of sensory systems, encoding models enable us to test and compare brain-computational models, and thus directly constrain computational theory. Encoding and decoding models typically include fitted linear-model components. Sometimes the weights of the fitted linear combinations are interpreted as reflecting, in an encoding model, the contribution of different sensory features to the representation or, in a decoding model, the contribution of different measured brain responses to a decoded feature. Such interpretations can be problematic when the predictor variables or their noise components are correlated and when priors (or penalties) are used to regularize the fit. Encoding and decoding models are evaluated in terms of their generalization performance. The correct interpretation depends on the level of generalization a model achieves (e.g. to new response measurements for the same stimuli, to new stimuli from the same population, or to stimuli from a different population). Significant decoding or encoding performance of a single model (at whatever level of generality) does not provide strong constraints for theory. Many models must be tested and inferentially compared for analyses to drive theoretical progress.Comment: 19 pages, 2 figures, author preprin

Potencial de fitoextracción de plomo de especies formadoras de céspedes

p.61-67El objetivo de este trabajo fue evaluar el potencial de fitoextracción de platas gramíneas cultivadas sobre suelos con altas concentraciones de plomo, Cynodon dactylon x C. transvaalensis cv. Tifway, Stenotaphrum secundatum (Walt.) Kunze, y Pennisetum clandestinum Hochst ex Chiov, cada una cultivada en parcelas, con dos niveles de contaminación (con y sin agregado de metal contaminante al suelo utilizando solución de Pb(NO3)2). No se detectaron diferencias significativas (p mayor a 0,05) entre las concentraciones de plomo en el suelo determinadas entre 0 y 3 cm de profundidad, al iniciar y al terminar el ensayo. Extracciones químicas secuenciales mostraron resultados coincidentes con los obtenidos a travéz de las extracciones simples con el agente quelante DTPA. Las concentraciones de Pb en la biomasa aérea en las parcelas contaminadas artificialmente, fueron de tan baja magnitud que las plantas estudiadas pudieron considerarse excluidoras del metal pesado, aunque el potencial de fitoextracción para kikuyo (Pennisetum clandestinum) fue alto

Variación de la concentración de fósforo a traves del tiempo en Cichorium Intybus

p.123-126En este trabajo se estableció la calidad nutritiva de la achicoria (Cichorium intybus, L.) con respecto a fósforo, a través del tiempo de crecimiento de las plantas. Las muestras fueron extraídas mensualmente y la concentración de fósforo fue determinada por el método de Fiske-Subbarow. El máximo contenido de fósforo por planta (µ pl planta) se obtuvo en el octavo mes después de la siembra

The impact of different rehabilitation strategies after major events in the elderly: the case of stroke and hip fracture in the Tuscany region

<p>Abstract</p> <p>Background</p> <p>On a regional level, our aims were to describe rehabilitation patterns for elderly patients with stroke and hip fracture and to investigate mortality risk during the 6-month post acute period.</p> <p>Methods</p> <p>Data sources included administrative data relative to patients aged 65+ resident in Tuscany admitted in hospital for stroke or hip fracture between 2001 and 2003, traced up to 3 years before and 6 months following index admission. The study design involves computerized linkage of administrative data, and an exploratory analysis of the association between rehabilitation patterns and 6-month mortality, adjusting for clinical, demographic, and acute-related care characteristics using multivariate Cox regression.</p> <p>Results</p> <p>Rehabilitation patterns vary greatly across Tuscany with considerable cost implications. Six month mortality risk for stroke patients is significantly lower among residents of Local Health Authorities where patients are more frequently rehabilitated, specifically in extra-hospital settings.</p> <p>Conclusion</p> <p>Our study, targeting two crucial conditions for elderly patients, found a high variability of rehabilitation patterns across a region, albeit coherent between the two pathologies, associated with remarkable differences in average expenditure. Differences in hazard rates for 6-month mortality after stroke at population level were also found. These results need to be confirmed and further investigated through a more robust information framework.</p

CHM/REP1 Transcript Expression and Loss of Visual Function in Patients Affected by Choroideremia

PURPOSE. To evaluate the disease progression in patients with clinical and genetic diagnoses of choroideremia during a long-term follow-up and to investigate the relationship between pathogenic variants in the CHM/REP1 gene and disease phenotypes. METHODS. We performed a retrospective longitudinal study on 51 affected men by reviewing medical charts at baseline and follow-up visits to extract the following ocular findings: best-corrected visual acuity, Goldmann visual field, optical coherence tomography, microperimetry. Data obtained from the analysis of DNA and mRNA were reevaluated for genetic classification of patients. RESULTS. The longitudinal analysis showed a significant (P < 0.001) worsening of best-corrected visual acuity with a mean rate of 0.011 logMar per year before 50 years and 0.025 logMar per year after 50 years. Similarly, V4e Goldmann visual field area significantly (P ≤ 0.01) decreased at a mean rate of 2.7% per year before 40 years and 5.7% after 40 years. Moreover, we observed a significant (P < 0.05) decrease of macular sensitivity with a mean rate of 5.0% per year and a decrease of mean macular thickness with a mean rate of 0.8% per year. We classified our patients into two groups according to the expression of the CHM/ REP1 gene transcript and observed that mutations leading to mRNA absence are associated with an earlier best-corrected visual acuity and Goldmann visual field loss. CONCLUSIONS. Our analysis of morphological and functional parameters in choroideremia patients showed a slow disease progression, particularly in the first decades of life. Overall, reevaluation of clinical and molecular data suggests exploring the genotype–phenotype relationship based on CHM/REP1 transcript expression. PURPOSE. To evaluate the disease progression in patients with clinical and genetic diagnoses of choroideremia during a long-term follow-up and to investigate the relationship between pathogenic variants in the CHM/REP1 gene and disease phenotypes. METHODS. We performed a retrospective longitudinal study on 51 affected men by reviewing medical charts at baseline and follow-up visits to extract the following ocular findings: best-corrected visual acuity, Goldmann visual field, optical coherence tomography, microperimetry. Data obtained from the analysis of DNA and mRNA were reevaluated for genetic classification of patients. RESULTS. The longitudinal analysis showed a significant (P < 0.001) worsening of best-corrected visual acuity with a mean rate of 0.011 logMar per year before 50 years and 0.025 logMar per year after 50 years. Similarly, V4e Goldmann visual field area significantly (P ≤ 0.01) decreased at a mean rate of 2.7% per year before 40 years and 5.7% after 40 years. Moreover, we observed a significant (P < 0.05) decrease of macular sensitivity with a mean rate of 5.0% per year and a decrease of mean macular thickness with a mean rate of 0.8% per year. We classified our patients into two groups according to the expression of the CHM/ REP1 gene transcript and observed that mutations leading to mRNA absence are associated with an earlier best-corrected visual acuity and Goldmann visual field loss. CONCLUSIONS. Our analysis of morphological and functional parameters in choroideremia patients showed a slow disease progression, particularly in the first decades of life. Overall, reevaluation of clinical and molecular data suggests exploring the genotype–phenotype relationship based on CHM/REP1 transcript expression

Genotoxic evaluation of sludge from Matanza-Riachuelo basin under the influence of different uses of land

El Río Matanza-Riachuelo y sus afluentes atraviesan zonas con diferente grado de contaminación generada por lasactividades agrícola-ganaderas, urbana e industrial. Los contaminantes que llegan al agua y son depositados en los sedimentospueden ser liberados nuevamente al agua generando efectos tóxicos y/o genotóxicos sobre los organismos acuáticos. El objetivode este trabajo fue analizar la genotoxicidad de muestras de sedimentos de la cuenca Matanza-Riachuelo obtenidas dezonas con diferentes usos del suelo. Se seleccionaron cuatro sitios de muestreo. Se utilizaron 2 métodos de extracción de contaminantes(agitación y sonicación), 2 solventes orgánicos (metanol y diclorometano) y 2 solventes inorgánicos (agua y soluciónácida), obteniéndose un total de 5 extractos para cada muestra. Se realizaron mediciones de metales pesados e hidrocarburosaromáticos policíclicos (HAPs) mediante espectrofotometría de absorción atómica y CG/MS, respectivamente. La genotoxicidadse evaluó mediante el test de Ames con 2 cepas de Salmonella typhimurium (TA98 y TA100), con y sin fracción microsomal S9,y el test de Allium cepa. De los cuatro sitios estudiados, los sedimentos del Riachuelo mostraron mayores concentraciones demetales pesados y HAPs. Para el test de Ames, sólo los extractos obtenidos en diclorometano resultaron genotóxicos para laTA100 +S9 mix. Tanto los extractos inorgánicos como los orgánicos fueron citotóxicos y genotóxicos para A. cepa. Se observóuna correlación negativa entre algunos compuestos HAPs y la frecuencia de micronúcleos, indicando la presencia de efectosantagónicos con otros compuestos genotóxicos. Los extractos con mayor efecto tóxico y genotóxico fueron los obtenidos condiclorometano y solución ácida. Este estudio mostró que los contaminantes orgánicos e inorgánicos extraídos de muestras desedimento de la Cuenca Matanza-Riachuelo, con diferente grado de impacto, presentan un potencial riesgo tóxico y genotóxicopara el ecosistema acuático.The Matanza-Riachuelo River and its tributaries traverse areas with different degrees of contamination due to farming, urban and industrial activities. The pollutants entering the water are deposited in sediments, and can be released back into the water producing toxic and/or genotoxic effects on aquatic organisms. The aim of this study was to analyze the genotoxicity of sediment samples from the Matanza-Riachuelo Basin with different land uses. Four sampling sites according to the characteristics of land use were selected. Two methods of extraction (stirring and sonication), two organic solvents (methanol and dichloromethane) and two inorganic solvents (water and acid solution) were used, yielding a total of 5 extracts for each sample. Measurements of heavy metals and polycyclic aromatic hydrocarbons (PAHs) by atomic absorption spectrophotometry and GC/MS, respectively were performed. Genotoxicity was assessed using the Ames test with 2 strains of Salmonella typhimurium (TA98 and TA100) with and without S9 microsomal fraction, and the Allium cepa test. Taking into account the four sites, sediments from Riachuelo showed higher concentrations of heavy metals and PAHs. Only the dichloromethane extracts were genotoxic to the Ames test using the TA100 strain +S9 the mix. Both organic and inorganic extracts were cytotoxic and genotoxic to A. cepa. A negative correlation between some PAHs compounds and micronucleus frequency were observed, indicating the presence of antagonistic effects with other genotoxic compounds in samples. The extracts with high toxic and genotoxic effects were obtained with dichloromethane and acid solution. This study showed that organic and inorganic contaminants extracted from sediment samples from the Matanza-Riachuelo Basin, with varying degrees of impact, have potential toxic and genotoxic risk to the aquatic ecosystem.Fil: Biruk, Lucia Nadia. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; ArgentinaFil: Moretton, Juan Agustin. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Filippetto, Javier. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Etcheverry, Jimena. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Weigant, Cristian. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Fabrizio de Iorio, Alicia Rosa. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Magdaleno, Anahí. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin