Is microrheometry affected by channel deformation?     

Francesco Del Giudice  Francesco Greco  Paolo Antonio Netti  Pier Luca Maffettone 《Biomicrofluidics》2016,10(4)

Microrheometry is very important for exploring rheological behaviours of several systems when conventional techniques fail. Microrheometrical measurements are usually carried out in microfluidic devices made of Poly(dimethylsiloxane) (PDMS). Although PDMS is a very cheap material, it is also very easy to deform. In particular, a liquid flowing in a PDMS device, in some circumstances, can effectively deform the microchannel, thus altering the flow conditions. The measure of the fluid relaxation time might be performed through viscoelasticity induced particle migration in microfluidics devices. If the channel walls are deformed by the flow, the resulting measured value of the relaxation time could be not reliable. In this work, we study the effect of channel deformation on particle migration in square-shaped microchannel. Experiments are carried out in several PolyEthylene Oxyde solutions flowing in two devices made of PDMS and Poly(methylmethacrylate) (PMMA). The relevance of wall rigidity on particle migration is investigated, and the corresponding importance of wall rigidity on the determination of the relaxation time of the suspending liquid is examined.  相似文献   

Are School-Provided Skills Useful at Work? Results of the Wiles Test     

Liwiński  Jacek  Pastore  Francesco 《Research in higher education》2021,62(1):72-97

Research in Higher Education - We test for the signaling hypothesis versus the human capital theory using the Wiles test in a country which has experienced a dramatic increase in the supply of...  相似文献   

Accuracy between optical and inertial motion capture systems for assessing trunk speed during preferred gait and transition periods     

Martin Kokholm Fleron  Niels Christian Hauerbach Ubbesen  Francesco Battistella  David Leandro Dejtiar 《Sports biomechanics / International Society of Biomechanics in Sports》2019,18(4):366-377

Motion capture through inertial sensors is becoming popular, but its accuracy to describe kinematics during changes in walking speed is unknown. The aim of this study was to determine the accuracy of trunk speed extracted using an inertial motion system compared to a gold standard optical motion system, during steady walking and stationary periods. Eleven participants walked on pre-established paths marked on the floor. Between each lap, a 1-second stationary transition period at the initial position was included prior to the next lap. Resultant trunk speed during the walking and transition periods were extracted from an inertial (240 Hz sampling rate) and an optical system (120 Hz sampling rate) to calculate the agreement (Pearson’s correlation coefficient) and relative root mean square errors between both systems. The agreement for the resultant trunk speed between the inertial system and the optical system was strong (0.67 < r ≤ 0.9) for both walking and transition periods. Moreover, relative root mean square error during the transition periods was greater in comparison to the walking periods (>40% across all paths). It was concluded that trunk speed extracted from inertial systems have fair accuracy during walking, but the accuracy was reduced in the transition periods.  相似文献   

Institutional experience of PTH evaluation on fine-needle washing after aspiration biopsy to locate hyperfunctioning parathyroid tissue     

Massimo Giusti  Mara Dolcino  Lara Vera  Carla Ghiara  Francesca Massaro  Laura Fazzuoli  Diego Ferone  Michele Mussap  Francesco Minuto 《Journal of Zhejiang University. Science. B》2009,10(5):323-330

Assaying parathyroid hormone (PTH) in the washing liquid after fine-needle aspiration biopsy (FNAB) seems to be a valid approach to locate parathyroid tissue. PTH-FNAB was evaluated in 47 patients with a clinical picture of primary hyper-parathyroidism (PHP) and ultrasonography (US) suggestive of parathyroid lesion. The patients were subdivided into two groups on the basis of the absence or presence of US thyroid alterations. The result of PTH-FNAB was compared with those of cytology, scintigraphy and, in 24 patients, surgical outcome. PTH-FNAB samples with a value higher than that recorded in the serum and higher than our institutional cut-off were deemed to be probable samples of parathyroid tissue. Cytology proved diagnostic for benign thyroid lesions, non-diagnostic for thyroid lesions, hyperplastic parathyroid tissue, undetermined or malignant thyroid lesions and other lesions in 45%, 30%, 17%, 4%, and 4% of cases, respectively. In 47% of cases, PTH-FNAB indicated that the sample had been taken in parathyroid tissue. In patients without US alterations, the diagnostic accuracy of PTH-FNAB was greater than that of scintigraphy. After surgery, comparison between the results of PTH-FNAB and scintigraphy, in terms of positive predictive value (PPV), revealed the superiority of PTH-FNAB; PPV was 94% for FNAB and 71% for scintigraphy, while sen-sitivity was 83% and 69%, respectively. PTH-FNAB evaluation after FNAB appears to be more diagnostic than cytology and scintigraphy. Of all the procedures used, PTH-FNAB appears to be the method of choice when the target is US suggestive and reachable. PTH-FNAB appears to be a useful method of guiding surgical intervention.  相似文献   

Foundational skills and dispositions for learning: an experience with Information Problem Solving on the Web     

Francesco Caviglia 《Technology, Pedagogy and Education》2016,25(4):487-512

Active participation in the information society requires the ability to find some order in the chaotic nature of the Web and not to get lost within the endemic presence of inaccurate, misleading, biased and false information. This article presents an approach to Information Problem Solving (IPS) – that is, finding, understanding and assessing information on the Web – and discusses a study carried out in an Italian secondary school, using an experimental and a control group. The study aimed at exploring how to best foster IPS skills, and observing whether and how IPS activities could promote the development of more general learning dispositions and competences. After a period of training with IPS activities, the experimental group showed different dispositions towards learning from a text and engaging with open-ended questions. Despite serious limitations in the depth of analysis, most students were able to reach acceptable solutions; at the same time, they felt empowered and developed an embryonic critical attitude on which it might be possible to build further.  相似文献   

Measuring Weathering and Nanoparticle Coating Impact on Surface Roughness of Natural Stones     

Simona Raneri  Jacopo Crezzini  Simona Arrighi  Francesco Boschin  Ilaria Alfieri  Germana Barone 《文物保护研究》2013,58(5):298-309

ABSTRACT

The surface texture of a stone represents a sensitive parameter in evaluating its conservation state. In monuments and sculptures, in fact, external agents continuously alter the appearance of stones, determining peculiar weathering patterns and modifying properties such as retention of water and particles, interaction with light, color, and finishing. The application of protective coatings also determines changes in surface appearance of a stone, usually evaluated and monitored by color change tests. Surface metrology methods offer the possibility to quantify these changes, evaluating the impact of external agents (natural, i.e. weathering, and artificially, i.e. protective coatings) on natural stones. In this research, we demonstrate the potential of surface areal measurements in describing the evolution of weathering processes and the effects of protective treatments on porous stone materials. The obtained results suggest that the extent of the modifications is related to the scale of observation (small- vs. large-scale undulations, i.e. roughness and waviness, respectively), with an overall increase of surface roughness as the weathering proceeds. Unexpectedly, coatings based on nanoparticle dispersions increase the topographic height parameters, due to the absence of a homogeneous film.  相似文献   

Felix Büchel, Andries de Grip and Antje Mertens, Editors, Overeducation in Europe. Current Issues in Theory and Policy, Edward Elgar, Cheltenam, UK (2003) (Xi+239pp., $105.00).     

Francesco Pastore   《Economics of Education Review》2006,25(6):682-683

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Agency online: trends in a university learning course     

Maria Beatrice Ligorio  Maria Antonietta Impedovo  Francesco Arcidiacono 《Technology, Pedagogy and Education》2017,26(5):529-543

This article aims to investigate how university students perform agency in an online course and whether the collaborative nature of the course affects such expression. A total of 11 online web forums involving 18 students (N = 745 posts in total) were qualitatively analysed through the use of a codebook composed of five categories (individual, interpersonal, epistemic, transformative and collective) and several sub-categories purposely developed for the sake of this research. The results show that each category follows a specific path, although two events – the re-mixing of the groups and the assumption of the peer-tutor role – particularly affected the evolution of trends. Although this study needs further development, the authors believe that an in-depth understanding of the nature of agency, including how to analyse it as well as empower it when implementing blended educational activities, engages relevant theoretical and pedagogical issues.  相似文献   

Collaboration,knowledge and innovation toward a welfare society: the case of the Board of Social Farming in Valdera (Tuscany), Italy     

Francesco Di Iacovo  Roberta Moruzzo 《The Journal of Agricultural Education and Extension》2017,23(4):289-311

Purpose: Through an analysis of a social farming (SF) case study, this article investigates how collaboration and knowledge co-creation between different actors can support the process of rural transition in order to stimulate innovation in the welfare system using agricultural resources.

Methodology: We used the ‘Antecedent-Process-Outcome Framework’ developed by Wood and Gray [1991. “Toward a Comprehensive Theory of Collaboration.” The Journal of Applied Behavioral Science 27 (2): 139-162] and adapted by Thomson and Perry [2006. “Collaboration Processes: Inside the Black Box.” Public Administration Review 66 (s1): 20-32], to analyse the collaborative process within the Board of Social Farming (BSF) in Valdera, Italy. The BSF in Valdera is particularly important as it was the first transition arena developed in Italy for SF development.

Findings: The article highlights the difficulties and opportunities encountered by the BSF in the knowledge co-creation and collaboration, and identifies key elements to facilitate innovation in SF and more generally in transition processes.

Practical implications: The article aims to generalize crucial practical elements in the relationship between collaborative approaches and innovation in the field of innovative welfare society, which is increasingly key to rural transition.

Theoretical implications: Innovation in SF is complex due to the need to identify new knowledge, diverse kinds of organizations and innovative interactions among many private and public stakeholders. The article explores the concept of collaboration in SF in order to re-define the production of public and private goods within local and rural communities.

Originality: The article aims to contribute to the ongoing discussion on the advantages and disadvantages of collaboration in order to reinforce rural transition pathways.  相似文献   

Biphasicity of the time-response curve and amnesic effect of electroconvulsive shock in passive avoidance conditioning     

Francesco Robustelli  Anne Geller  Murray E. Jarvik 《Learning & behavior》1973,1(4):251-253

Mice were trained in a one-trial passive avoidance task and retested 2 min, 5 min, 10 min, 30 min, or 24 h later. A biphasic time-response curve was obtained with art initial increase to 5 min, a subsequent decrease, and another increase to 24 h. Other groups of Ss were administered electroconvulsive shock (ECS) 2, 5, 10, or 30 min after training and retested 24 h later. The response curve shape of the ECS-treated groups was found to correspond to that concerning the different retest times, suggesting a negative correlation between ECS amnesic effect and the strength of the conditioned response at the time of ECS administration. The inadequacy of the hypotheses, according to which ECS interferes with a gradual monotonic process, to explain ECS amnesic effect is discussed.  相似文献