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21.
The knowledge of the morphological and mechanical properties of masonry walls is very important for the refurbishment of ancient buildings, particularly when the requirements of both structural safety and historical preservation must be fulfilled. The masonry is not of homogenous material: its mechanical properties depend on stones, mortar, and texture which are very variable due to their dependence on the historical periods and the geographical area of the erection. For this reason, a deep knowledge of masonries built in different sites and historical periods is essential in order to evaluate both the capacities of bearing vertical load and the seismic vulnerability of the masonry structure. Three fundamental typologies of tuff masonry have been defined: they are the characteristics of different historical periods from the XVI to the XX century. The models are in full-scale in order to reproduce the three defined chronotypes. Original tuff stones quarried in the corresponding historical period, mortars similar to the original ones, reproduced according to ancient documents and original constructive techniques have been used for the construction of the specimens. Compression tests performed in displacement control have been carried out on the masonry models in order to determine the maximum resistance of the material and the corresponding strain, the ultimate strain and corresponding residual strength. In this paper, the procedure used for making the specimens and for experimentally evaluating the mechanical properties of post-medieval Neapolitan yellow tuff masonry are illustrated and the obtained results, even in terms of plastic capacity of these kinds of masonry, are reported.  相似文献   
22.
The Gravity-Powered Calculator is an exhibit of the Exploratorium in San Francisco. It is presented by its American creators as an amazing device that extracts the square roots of numbers, using only the force of gravity. But if you analyze his concept construction one can not help but recall the research of Galileo on falling bodies, the inclined plane and the projectile motion; exactly what the American creators did not put into prominence with their exhibit. Considering the equipment only for what it does, in my opinion, is very reductive compared to the historical roots of the Galilean mathematical physics contained therein. Moreover, if accurate deductions are contained in the famous study of S. Drake on the Galilean drawings and, in particular on Folio 167 v, the parabolic paths of the ball leaping from its launch pad after descending a slope really actualize Galileo’s experiments. The exhibit therefore may be best known as a ‘Galilean calculator’.  相似文献   
23.
How to reduce university drop-out is a topic of increasing concern. Although several measures have been the subject of numerous debates, little attention has been given to those impacting on the duration, structure and content of the supply of university education. This paper looks at the Italian experience to see what can be learnt about the effectiveness of these measures. In 2001, the Italian university system embarked on a process of reform that introduced greater flexibility in the degree programme structure along with a wider range of services offered to students. Employing a decomposition analysis, we find that this reform is associated with changes in student behaviour leading to a decline in drop-out risk.  相似文献   
24.
The effects of signal duration when choosing between signaled and unsignaled response-independent reinforcers were examined in two experiments. In Experiment 1, albino rats were given a choice between signaled and unsignaled food delivered on variable-time 60-sec schedules using a 20-sec signal. All subjects preferred the signaled schedule at a level comparable to that reported in an earlier study using a 5-sec signal. Experiment 2 presented six rats with a direct choice between a 5-sec and a 20-sec signal condition, and three rats with a choice between a 1.5-sec and a 5-sec signal duration. Subjects preferred the 20-sec signal over the 5-sec signal, but no pReference was found with the 1.5-sec vs. a 5-sec signal. Current theoretical views, such as delay reduction and behavioral competition, are considered.  相似文献   
25.
Abstract

The aim of the study was to compare the effect of an unsupervised whole body vibration (WBV) training and two different supervised multi-purpose exercise programmes, with and without WBV, on body composition, functional fitness and self-reported well-being in middle-aged adults. Fifty-four healthy participants (age 48.6 ± 6.7 years) were randomly assigned to a vibration group (VG), a multi-purpose exercise group (MG) and a multi-purpose exercise with vibration group (VMG) and trained 3 days a week for 4 months. VG performed a standardised unsupervised WBV protocol, MG a supervised multi-purpose exercise and VMG a multi-purpose exercise including vibration. After training, drop out was significantly higher in VG group (P = 0.016) when compared to VMG group. In both MG and VMG, body composition, sit-up, push-up, sit and reach, agility test, hopping test and self-reported general health significantly improved (P < 0.05). No additive effects were generated by the vibration stimulus. Percentage of body fat and agility test in VG had a significant opposite trend compared to VMG group (P < 0.05). In summary, an unsupervised WBV training should not be chosen for training protocol. However, positive effects on physical fitness and the best results in adherence could be achieved integrating WBV practice into a multi-purpose exercise training.  相似文献   
26.
In this paper we analyse the extent to which the quality of teaching and research inputs, as measured by Quality Assurance Agency (QAA) and Research Assessment Exercise (RAE) scores, can account for variations in the employability of taught postgraduates. Pooling data from the 1997, 1998 and 1999 First Destinations Surveys we estimate regression equations for male and female UK postgraduates. Our results suggest that the lack of direct financial rewards associated with a higher QAA score may have persuaded many institutions to adopt a ‘threshold’ approach to Subject Review. However, the impact of RAE score suggests that students in institutions with a stronger research culture do have enhanced levels of employability. This is in line with the strong emphasis on active research input mandated by many professional bodies at the postgraduate level. When considered alongside recent policy pronouncements, this suggests that many institutions choosing to become teaching‐only, may ultimately risk becoming undergraduate‐only.  相似文献   
27.
This study examines the contribution of learner cognitive and motivational characteristics to achievement in science at three grade levels. Specifically, the relations between domain-specific epistemic beliefs about the development and justification of scientific knowledge, achievement goals, knowledge, self-concept, self-efficacy, and achievement in science were simultaneously examined. Students in fifth (n = 213), eighth (n = 202), and eleventh (n = 281) grades completed questionnaires measuring the various constructs, and a domain knowledge test. Their grades in science were also collected. Results from structural equation modeling reveal that the hypothesized model fitted the observed data at the three grade levels, although not all expected paths were statistically significant. Students’ epistemic beliefs about the development of scientific knowledge had a direct effect on domain knowledge, whereas beliefs about the justification of scientific knowledge had a direct and an indirect effect via achievement goals on knowledge acquisition. Mastery, performance-approach, and performance-avoidance goals had a direct effect on self-efficacy. Knowledge had a direct and an indirect effect via self-concept on achievement. Educational implications are discussed.  相似文献   
28.
Abstract

The purpose of this paper was to understand which differences long-term swimming training can cause on trunk mechanics during breathing and how these differences are related to the years of swimming training. The variations and coordination among trunk compartments were considered as target movement patterns. Video-based plethysmography was utilised for data acquisition and pre-processing. A group of swimmers, who followed a long-term intensive swimming training previously to this study, was compared with a non-swimmer control group. The participants of both groups performed quiet breathing and vital capacity tests. From the compartmental volumes associated with each breathing curves, the relative amplitude and cross-correlation among these volumetric time-varying signals were calculated, in order to analyse the relative partial volume variation and the coordination among trunk compartments involved in respiration. The results of a Mixed-ANOVA test (P ≤ 0.05) revealed higher coefficient of variation (P < 0.001) and correlations among trunk compartments in the swimmers group when vital capacity was performed. Significant linear regression was found between the years of swim training and the coefficients of variation and correlation. The results suggest that after long periods of intensive swim training, athletes might develop specific breathing patterns featuring higher volume variations in the abdominal region and more coordination among compartments involved in forced respiratory tasks such as vital capacity.  相似文献   
29.
A choice and a conditioned suppression procedure were used to assess concurrently the positive and negative properties of stimuli within a signaled shock schedule, Occasional shocks were presented to Ss responding on a variable-interval food schedule. Ss could choose whether shocks occurred alone or whether they were preceded by a 1-min signal. All Ss chose the signaled shock condition over the unsignaled one, even though food reinforced responding in the presence of the signal was suppressed. Rate of responding for food varied across stimulus conditions, with the lowest rate in the presence of the signal and the highest rate in its absence. An intermediate rate occurred under the unsignaled shock schedule. A safety analysis was applied to the data.  相似文献   
30.
In this study, 100 Italian eighth graders were divided into two groups to compare the effects of two instructional interventions – the first based on problem-solving through discussion, the second on individual problem-solving – on students' learning of two historical topics (World War I and the economic boom), interest and self-perception of competence in history. The intervention based on discussion produced greater situational interest and understanding of the historical inquiry. The topic of World War I turned out to be an effective source of situational interest. Structural equation models showed that situational interest elicited by the use of discussion and by World War I impacted both on students' individual interest and on self-perception of competence in history.  相似文献   
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