ENSO effects on primary productivity in Southern Atacama desert

Journal ArticleIn the winter-rain southern Atacama Desert of the Coquimbo Region of Chile, El Niño - Southern Oscillation (ENSO) events modulate primary productivity. In this region, there are important changes in water availability between La Niña (dry) and El Niño (rainy) years. Using interannual comparisons of LANDSAT images from 30o to 31o S latitude, we observed changes in primary productivity between dry and rainy years at the regional level

Successful Applications of NIR Spectroscopy and NIR Imaging in the Food Processing Chain

Forty years ago, Near InfraRed (NIR) was considered a sleeping technique among the spectroscopic ones. Thanks to the technological advances suffered in recent decades, we can say that NIR is now a consolidated technique, and with rapidly increasing applications. After attracting more attention inside the laboratories, NIR Spectroscopy (NIRS) moved out of them, being used in companies (in-line and on-line process control), various fields (airborne devices and handheld devices), and even space (satellites). Many factors have contributed to this success story, whose end is, we believe, still far from being written. Several of the most important are cited here: the economic accessibility of powerful devices, the technical evolution of the instrumentation, and the acceptance of the use of chemometrics, whose impact in the field on NIRS is absolutely needed due to the chemical and physical features of NIR radiation. Other factors, such as the miniaturization of the instruments and the association with imaging techniques, which occurred with the launch of the 4th industrial revolution and the development of the Industry 4.0 paradigm, have been pivotal

Herbivory and plant growth rate determine the success of El Niño Southern Oscillation-driven tree establishment in semiarid South America

While climatic extremes are predicted to increase with global warming, we know little about the effect of climatic variability on biome distribution. Here, we show that rainy El Niño Southern Oscillation (ENSO) events can enhance tree recruitment in the arid and semiarid ecosystems of north-central Chile and northwest Peru. Tree-ring studies in natural populations revealed that rainy El Niño episodes have triggered forest regeneration in Peru. Field experiments indicate that tree seedling recruitment in Chile is much less successful than in Peru due mostly to larger mortality caused by herbivores. The dramatic impact of herbivores in Chile was derived from the combined result of slower plant growth and the presence of exotic herbivores (European rabbits and hares). The interplay of herbivory and climatic effects we demonstrated implies that rainy ENSO events may represent 'windows of opportunity' for forest recovery if herbivore pressure is minimized at the right momen

Tecnologie di lavorazione di polimeri ad altissime prestazioni

Nello sviluppo tecnologico degli ultimi anni, stanno acquisendo sempre più importanza i polimeri ad altissime prestazioni, o tecnopolimeri, che sono materiali polimerici candidati alla sostituzione di materiali più nobili. Componenti finiti in tecnopolimero possono essere realizzati mediante stampaggio ad iniezione o asportazione di truciolo da semilavorati. Tuttavia, nella lavorazione dei tecnopolimeri esiste una forte interdipendenza tra proprietà dei materiali, variabili di processo e soluzioni tecnologiche; ciò purtroppo rende molto spesso non prevedibili le prestazioni finali dei pezzi lavorati. Considerando, inoltre, che i tecnopolimeri richiedono alti costi sia per la loro acquisizione che per l’allestimento dei sistemi di lavorazione, è chiaro come nasca l’esigenza di approfondire la conoscenza su questi materiali e sulle loro tecnologie di trasformazione. Tali problematiche hanno portato alla definizione della presente tesi. Al fine di conoscere le proprietà dei materiali vergini e processati, sono state analizzate le tecniche di qualificazione dei materiali polimerici, ampliandone la famiglia con l’introduzione dell’indentazione strumentata, che consente di effettuare prove a velocità costante e a carico costante (creep), correlabili con tradizionali test di trazione. Per incrementare il know-how relativo alle problematiche del processo di stampaggio ad iniezione, è stata acquisita una pressa totalmente elettrica, equipaggiata con un misuratore di energia per valutare l’impatto energetico dei processi di stampaggio. Inoltre sono stati affrontati casi studio su componenti industriali, che hanno messo in luce quanto variegata possa essere la risposta dei vari materiali alle diverse condizioni di stampaggio, tanto da inficiare le prestazioni di esercizio dei componenti finali. Infine si sono analizzate le problematiche relative al processo di asportazione di truciolo dei tecnopolimeri, impiegato per la fabbricazione di ridotti volumi di produzione. Fattore critico è la distribuzione delle proprietà e delle tensioni residue nei semilavorati di partenza, che causano l’insorgere di distorsioni nei pezzi finiti. Tutti gli studi sono stati svolti con l’idea di inquadrare i processi di lavorazione dei polimeri ad altissime prestazioni in un’ottica globale, dal perseguimento di proprietà meccaniche, predefinite tramite l’utilizzo dei metodi di simulazione numerica e sistemi sperimentali, all’attenzione per i consumi energetici e al rispetto ambientale.In the recent technological developments, high performance polymers have gained more and more importance. These polymers are potential replacements of nobler materials. High performance parts can be produced by means of injection molding or machining of semi-finished products. However, high performance polymer processing is influenced by a strong interdependence between material properties, process parameters and technological choices; as a result, finished product performances are often unpredictable. Moreover, these polymers are very expensive, either considering the raw material and the manufacturing system costs, therefore it is very important to study in depth their properties and processing. These key issues led to the definition of this doctoral dissertation. Conventional characterization tests of polymers were analyzed to define a methodology which allows to investigate raw and processed material properties. The characterization techniques were extended by introducing the instrumented indentation test. This innovative test can be performed at fixed speed or fixed load (creep test) and its results can successfully be correlated with traditional tensile test results. An electric injection molding machine was acquired and equipped with an energy meter, in order to increase the knowledge about injection molding process and its energy requirements. Furthermore, some case studies of industrial injection molded components were considered; the production process heavily influences the material properties, so far as to affect the performances of the finished parts. Finally, critical aspects related to the machining of high performance polymers were analyzed. Machining processes are used when the production volumes are small. The distribution of material properties and residual stresses in the semi-finished products may produce the warpage of the plastic part during machining. All these studies were performed with the idea of setting the high performance polymer manufacturing processes in a global view, from the need of achieving the required mechanical properties (defined by means of numerical simulation and experimental methods), to the evaluation of energy consumption

The potential of apulian olive biodiversity: The case of oliva rossa virgin olive oil

In this study, the drupes and virgin olive oils extracted from the Oliva Rossa landrace are characterized. Oliva Rossa is an old landrace part of the autochthonous Apulian olive germplasm for which only few data have been reported till now. During the study, the maturity patterns of the drupes had been followed. Four samplings per year were planned, one every 14 days starting from the middle of October. The pigmentation index, the oil content and the total phenolic content of the drupes were measured. Simultaneously, virgin olive oils were extracted at the lab scale and analyzed for the fatty acid composition, the basic quality parameters and the content of minor compounds. The pigmentation pattern of the drupes was different among the years and, despite this trend, at the third sampling time the stage of maximum oil accumulation was always over. The extracted virgin olive oils had a medium to high level of oleic acid. With colder temperatures, a higher level of monounsaturated fatty acids, oleic/linoleic ratio and antioxidants was observed. The phenolic profile was dominated by 3,4-DPHEA-EDA and p-HPEA-EDA while the volatile profile by (E)-2-hexenal and 3-ethyl-1,5-octadiene

Comparative study of total phenolic content and antioxidant properties of Quercus fruit: flour and oil.

Aim:The currentstudywas undertaken to determinethe total phenolic and flavonoid contents and toassessthe antioxidant activity of two different extracts (flour and oil) of two Algerian Quercus species, Quercus ilexL. and Quercus suberL. Methods and Material:The oil extraction of the two species was achieved using the Soxhlet method. The obtained extracts were estimated for the chemical and physical constants (acidity, peroxide value, iodine value,and ultraviolet absorption indices). Total phenolic content was measuredby spectrophotometryaccording to the Folin-Ciocalteu procedure and calculated as gallic acid equivalents (GAE). The studied extracts were alsosubmitted to an estimation of their flavonoid contents too,using aluminum chloride methods. Antioxidant ability was assessed by means oftwo distinctmethods (DPPH• and ABTS•+).Results:The obtained results revealed that antioxidant properties, total phenolic,and total flavonoid contents differed significantly among selected species and extracts. The flour samples possessed the highest level of totalphenolic contents (1101–1464 mg GAE/kg dry weight) and exhibited the highest antioxidant capacities with average values of 52.62–40.78 μmol TE g−1dry weight and 36.19–44.50 μmol TE g−1dry weight for DPPH and ABTS assays, respectively. Acorn oil extractsshowed also remarkable antioxidant activity, up to 2.69 and 3.23 μmol TE g−1oil (DPPH and ABTS test, respectively), even though the total phenolic contents were low (195.64–322.06 mg GAE /kg of oil). Total phenolic amounts were positively correlated withtheantioxidant properties of Quercus flour and oil.Conclusions:Ourstudy provides basic information on the presence of bioactive compounds and antioxidant capacity in acorn fruits, in order to consider their extracts as functional food ingredients and potential source of natural antioxidants

Análisis de la relación entre las estrategias de control y la discrepancia de tiempo y mortalidad en la ejecución de las actividades involucradas en el sistema logístico humanitario colombiano a través de la metodología integral y dinámica.

88 páginasEl presente trabajo busca analizar la relación que hay entre las estrategias de control aplicadas a la logística humanitaria y el efecto que estas puedan tener sobre el tiempo de ejecución de las actividades y la mortalidad en un desastre. Para lograr esto se procedió a realizar la caracterización del sistema logístico humanitario colombiano, específicamente en el subsistema de búsqueda y rescate, con el fin de poder identificar cuáles son las actividades involucradas, los responsables y los recursos que son utilizados. Se realizaron entrevistas a profesionales de los entes encargados en conjunto con la aplicación de las técnicas de OBS, WBS y matriz de responsabilidades, para poder desglosar el subsistema de búsqueda y rescate e identificar procedencias, dependencias entre actividades, recursos y responsables. Seguidamente, se realizó una búsqueda en literatura publicada, en donde se identificaron estrategias de control aplicadas a la logística en sus distintas áreas, pero no se evidenciaron estrategias de control aplicadas a la logística humanitaria, lo que trajo como consecuencia la búsqueda identificación de características que permitieran la elaboración de una estrategia para el control en la logística humanitaria. La jerarquización de estas características se realizó a través de la utilización del método AHP, lo cual permitió elegir las potenciales características que permitiera construir la estrategia de control. Posteriormente se realizó el análisis de la estructura sistémica y la elaboración del modelo con el fin de obtener el Modelo Dinámico del Sistema de Atención de desastres colombiano en la Fase de Respuesta. Nota: Para consultar la carta de autorización de publicación de este documento por favor copie y pegue el siguiente enlace en su navegador de internet: http://intellectum.unisabana.edu.co/handle/10818/1579

High total cholesterol in peripheral blood correlates with poorer hearing recovery in idiopathic sudden sensorineural hearing loss

Idiopathic sudden sensorineural hearing loss (ISSHL) is a common otologic emergency whose cause is still unclear. The importance of blood lipids in the pathogenesis of ISSHL is widely reported in literature. In fact elevated levels of low density lipoprotein cholesterol (LDL), total cholesterol (TC) and apolipoprotein B (Apo-B) have been proposed as risk factors for this pathology. No correlation has been described between serum lipid parameters and the prognosis of ISSHL. Aim of the present study was to identify prognostic factors associated with hearing recovery in a group of patients affected by ISSHL. Ninety-four patients with the diagnosis of ISSHL hospitalized between March 2013 and October 2014 were included in this study. Patients' blood sampling and hearing assessments were carried out. Patients were divided into two groups as "recovered" and "unrecovered", according to their response to the treatment. We found a statistically significant higher level of total cholesterol in the unrecovered group compared to the recovered one (p = 0.03). None of the other routine laboratory parameters have shown a statistically significant difference between the patients successfully treated and patients with poor outcomes. Total cholesterol concentrations may be a prognostic factor for recovery in ISSHL and should be assessed together with routine tests in patients with this condition. The other routine laboratory parameters seem to have no effect on the development and prognosis of this pathology