3,901 research outputs found
PCL/POSS Nanocomposites: Effect of POSS Derivative and Preparation Method on Morphology and Properties
The incorporation of polyhedral oligomeric silsesquioxanes (POSS) molecules as nanoparticles into polymers can provide improved physico-chemical properties. The enhancement depends on the extent of dispersion of the nanofiller, which is determined by the compatibility with the polymer that is by the POSS type, and the processing method. In this study, poly(epsilon-caprolactone)/POSS derivatives nanocomposites (PCL/POSS) were obtained via solution-casting and melt compounding. Two amino-derivatives containing different alkyl substituents, and ditelechelic POSS-containing hybrid PCL masterbatch were used as nanofillers. The effect of preparation method, POSS content and type on the morphology, thermal, mechanical, and surface properties of nanocomposites were studied. Morphological analysis evidenced the formation of POSS crystalline aggregates, self-assembled POSS molecules of submicrometer size dispersed in the polymer matrix. The best dispersion was achieved using the ditelechelic POSS-containing hybrid PCL masterbatch, and comparing the two amino-POSS derivatives, the one with longer alkyl chain of substituents exhibited better degree of dispersion independent of preparation method. DSC analysis showed the role of POSS derivatives as nucleating agents for PCL. The incorporation of POSS derivatives into the PCL matrix improved thermal stability. The preparation method, POSS type and content had influence on mechanical properties of nanocomposites. POSS nanoparticles enhanced the surface hydrophobicity of PCL.This research was funded by the Basque Government (SAIOTEK 2012 S-PE12UN006) and the University of the Basque Country (UFI11/56)
A methodology for constructing fuzzy rule based classification systems
In this paper, a methodology to obtain a set of fuzzy rules for classification systems is presented. The system is represented in a layered fuzzy network, in which the links from input to hidden nodes represents the antecedents of the rules, and the consequents are represented by links from hidden to output nodes. Specific genetic algorithms are used in two phases to extract the rules. In the first phase an initial version of the rules is extracted, and in second one, the labels are refined. The procedure is illustrated by applying it to two real-world classification problem
The relative value of environmental context reinstatement in free recall
[EN]The effect of environmental context on episodic memory was examined in
two free recall experiments with groups of old and young subjects. All
subjects studied a list of unrelated words and were subsequently tested in the
same room or in a different room. The results of Experiment 1 showed an
advantage of being tested in the same context for the old subjects, but no
effects of the context manipulation for the young subjects. Experiment 2
replicated this finding and additionally showed that old subjects (but not
young subjects) benefited from instructions to mentally reinstate the
learning context. The results of both experiments are discussed in terms of
the relative value of contextual cues for subjects in each of the two age
groups.Junta de Castilla y LeónMinisterio de Educación y Cultur
SWATH Differential Abundance Proteomics and Cellular Assays Show In Vitro Anticancer Activity of Arachidonic Acid- and Docosahexaenoic Acid-Based Monoacylglycerols in HT-29 Colorectal Cancer Cells
Colorectal cancer (CRC) is one of the most common and mortal types of cancer. There is increasing evidence that some polyunsaturated fatty acids (PUFAs) exercise specific inhibitory actions on cancer cells through different mechanisms, as a previous study on CRC cells demonstrated for two very long-chain PUFA. These were docosahexaenoic acid (DHA, 22:6n3) and arachidonic acid (ARA, 20:4n6) in the free fatty acid (FFA) form. In this work, similar design and technology have been used to investigate the actions of both DHA and ARA as monoacylglycerol (MAG) molecules, and results have been compared with those obtained using the corresponding FFA. Cell assays revealed that ARA- and DHA-MAG exercised dose- and time-dependent antiproliferative actions, with DHA-MAG acting on cancer cells more efficiently than ARA-MAG. Sequential window acquisition of all theoretical mass spectra (SWATH)—mass spectrometry massive quantitative proteomics, validated by parallel reaction monitoring and followed by pathway analysis, revealed that DHA-MAG had a massive effect in the proteasome complex, while the ARA-MAG main effect was related to DNA replication. Prostaglandin synthesis also resulted as inhibited by DHA-MAG. Results clearly demonstrated the ability of both ARA- and DHA-MAG to induce cell death in colon cancer cells, which suggests a direct relationship between chemical structure and antitumoral actions
Measuring Students’ Information Literacy Skills through Abstracting : Case Study from a Library & Information Science Perspective
P. 132-154New education models based essentially on competencies and skills are gradually displacing the old systems based on teacher instruction and passive and memory-based learning in students, as these new competencies allow the student to learn actively with better levels of performance.We consider abstracting as a transcendent learning tool to analyze the basic role of information analysis and synthesis skills within the learning processes and their relation to the abstracting processes. Using an action-research methodology, we analyze the abstracting skill of students on the first and final courses of the Faculty of Library and Information Science at the University of Granada (Spain). Based on postulates from information literacy, analysis and synthesis competencies are studied through the students’ modus operandi at the different abstracting stages. Similarities and differences between the two groups of students are perceived and displayed, with reference to the relation between the learned subjects and the levels of competence and skill. In the light of these results, meaningful patterns and recommendations for improving students’ skill levels are proposed.S
A set of 750 words in Spanish characterized in two survival-related dimensions: avoiding death and locating nourishment
[EN]With the aim of finding quantitative indicators of the survival relevance for a set of concrete concepts, a subjective rating task was
administered to a large sample of college students (N = 300). In the rating task, participants used a five-point scale to rate 750
concepts in one of two survival-relevant dimensions, providing their own judgment about the relevance of each concept in a
situation in which either avoiding death (AD) or obtaining food (OF) was of importance. The subjective ratings showed high
stability and reliability and showed varied patterns of association to potentially relevant concept-defining variables, with corre lational analyses showing both commonalities and differences between the two rated dimensions. Regression analyses indicated
that, while not likely to modulate word accessibility, survival ratings were related to certain conceptual properties that could be
especially sensitive for threat detection. The collected data set provides normative information that can be of use in manipulating
and controlling verbal stimuli in future research focusing on adaptive properties of episodic memory and other aspects of the
human cognitive system. The complete norms are available for downloading at Open Science Framework (https://osf.io/sf9mb/)
Measuring students’ information skills through concept mapping
This paper seeks to develop a methodology that will discover, specify and measure students’ abilities and skills in creating concept maps. Because competencies are the key factor in higher education, the paper analyses the role of concept maps as a tool to diagnose and improve information analysis, synthesis, organisation and representation skills and competencies. We propose a methodology that enables these skills to be evaluated by observing, analysing and measuring the stages involved in creating a concept map: identification of the main and secondary subjects; subject
codification by concepts; grading of concepts; and representation of the concepts and their relationships with labels. A case study using action-research methodology tests the usefulness of the methodology on a group of university students of Library and Information Science. The method proposed provides information on the strengths and weaknesses of the students’ skills analysed, thus enabling their training to be improved by means of specific actions
Measuring students' information literacy skills through abstracting: case study from a library and information science perspective.
New education models based essentially on competencies and skills are gradually displacing the old systems based on teacher instruction and passive and memory-based learning in students, as these new competencies allow the student to learn actively with better levels of performance. We consider abstracting as a transcendent learning tool to analyze the basic role of information analysis and synthesis skills within the learning processes and their relation to the abstracting processes.
Using an action-research methodology, we analyze the abstracting skill of students on the first and final courses of the Faculty of Library and Information Science at the University of Granada (Spain). Based on postulates from information literacy, analysis and synthesis competencies are studied through the students’ modus operandi at the different abstracting stages. Similarities and differences between the two groups of students are perceived and displayed, with reference to the relation between the learned subjects and the levels of competence and skill. In the light of these results, meaningful patterns and recommendations for improving students’ skill levels are proposed
The role of information competencies and skills in learning to abstract
The ability to abstract information is a basic competency in today’s knowledge society, characterised by the mass diffusion of information and the need to manage and access it effectively. Yet abstracting is not an easy task, and requires a specific learning process. This paper examines the process of abstracting information from the perspective of competencies and skills based learning. The competencies and skills necessary in this process are identified by analysing in detail the various stages and processes involved in writing an abstract. The general skills required for the whole process, as well as the specific skills for each stage, are determined. Guidelines and recommendations are put forward to facilitate the learning of these skills in the context of abstracting
Plan para la implementación de un departamento de servicios de RRPP digitales en la empresa Taktikee Consultores de Comunicación Cia. Ltda.
El tema elegido para esta disertación responde a motivaciones personales,
académicas y profesionales. Tras haber adquirido experiencia laboral por casi dos años
en la agencia de comunicación y relaciones públicas, Taktikee y recibir formación
académica por cuatro años, descubrí no solo gran interés por la comunicación, sino una
pasión especial por la naturaleza de las nuevas tecnologías y su repercusión en la
comunicación
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