Photoluminescence of the inorganic pigments Egyptian blue, Han blue and Han purple     

Giorgio Pozza  David Aj  Giacomo Chiari  Franco De Zuane  Marialuisa Favaro 《Journal of Cultural Heritage》2000,1(4)

The room-temperature photoluminescence spectra of various samples of Egyptian blue (CaCuSi₄O₁₀) are presented, discussed and compared with those of recently synthesized compounds corresponding to the ancient pigments Han blue (BaCuSi₄O₁₀) and Han purple (BaCuSi₂O₆). All the samples of Egyptian blue show identical spectra, in spite of their very different origin. The spectra of Han blue and Han purple are significantly different. Since the Cu²⁺ ion may be considered the only luminescent centre in the spectral range under investigation, the differences between the spectra of the various pigments are ascribed to a ligand-field change. This can be related to the larger size of the Ba²⁺ ion with respect to Ca²⁺. The use of PL spectra for the identification of these pigments in works of art is proposed.  相似文献   

Leadership Development through Mentoring in Higher Education: A Collaborative Autoethnography of Leaders of Color     

Heewon Chang  Karen A. Longman  Marla A. Franco 《Mentoring & Tutoring: Partnership in Learning》2014,22(4):373-389

In this collaborative autoethnography, we explored how 14 academic and administrative leaders of color working in faith-based higher education have experienced personal and professional mentoring, and how mentoring experiences have influenced their leadership development. All participants identified a wide array of developmental relationships that had contributed to their leadership development, although not all of the relationships were labeled as mentoring. Whereas female participants (11 in total) relied on these relationships primarily for psychosocial support, three male participants had more actively sought out mentoring relationships to develop career skills and expand their professional network. Particularly, for the female participants, mentoring took place mostly outside their professional settings. We argue that personal and institutional factors contributed to the participants’ limited access to professional mentoring within their higher education contexts. This collaborative autoethnography process, which lasted at least six months for most participants, unexpectedly provided professional mentoring opportunities for these leaders of color.  相似文献   

Sprint start kinematics during competition in elite and world-class male and female sprinters     

Simone Ciacci  Franco Merni  Sandro Bartolomei 《Journal of sports sciences》2017,35(13):1270-1278

The start kinematics has been reported to differ between male and female sprinters. This study aimed to determine whether kinematic differences between the sexes are attributable to an effect of sex per se, or rather to the absolute performance level of the sprinters, quantified by the 100-m time. A total of 20 sprinters (10 M, 10 F), including world-class and elite athletes, were assessed. Start phases from the “set” position to the first two steps were analysed. Linear regression analyses showed a few significant differences between sexes when taking into account the effect of performance level: M had shorter pushing phase duration, higher horizontal velocity at block clearing, and shorter contact times of the first two steps. Conversely, the performance level affected most of the examined parameters: faster sprinters showed the centre of mass (CM) closer to the ground and a more flexed front knee in the “set” position, longer pushing phase duration, lower vertical velocity of the CM at block clearing, and longer contact times and shorter flight times in the first two steps. These findings suggest that the start kinematics is only partially affected by the sex of sprinters, whereas a bigger role is played by their performance level.  相似文献   

Factors influencing physiological responses to small-sided soccer games   总被引：3，自引：2，他引：1  

Rampinini E  Impellizzeri FM  Castagna C  Abt G  Chamari K  Sassi A  Marcora SM 《Journal of sports sciences》2007,25(6):659-666

The aim of this study was to examine the effects of exercise type, field dimensions, and coach encouragement on the intensity and reproducibility of small-sided games. Data were collected on 20 amateur soccer players (body mass 73.1 +/- 8.6 kg, stature 1.79 +/- 0.05 m, age 24.5 +/- 4.1 years, VO(2max) 56.3 +/- 4.8 ml x kg(-1) x min(-1)). Aerobic interval training was performed during three-, four-, five- and six-a-side games on three differently sized pitches, with and without coach encouragement. Heart rate, rating of perceived exertion (RPE) on the CR10-scale, and blood lactate concentration were measured. Main effects were found for exercise type, field dimensions, and coach encouragement (P < 0.05), but there were no interactions between any of the variables (P > 0.15). During a six-a-side game on a small pitch without coach encouragement, exercise intensity was 84 +/- 5% of maximal heart rate, blood lactate concentration was 3.4 +/- 1.0 mmol x l(-1), and the RPE was 4.8. During a three-a-side game on a larger pitch with coach encouragement, exercise intensity was 91 +/- 2% of maximal heart rate, blood lactate concentration was 6.5 +/- 1.5 mmol x l(-1), and the RPE was 7.2. Typical error expressed as a coefficient of variation ranged from 2.0 to 5.4% for percent maximal heart rate, from 10.4 to 43.7% for blood lactate concentration, and from 5.5 to 31.9% for RPE. The results demonstrate that exercise intensity during small-sided soccer games can be manipulated by varying the exercise type, the field dimensions, and whether there is any coach encouragement. By using different combinations of these factors, coaches can modulate exercise intensity within the high-intensity zone and control the aerobic training stimulus.  相似文献   

Delayed preconditioning-mimetic actions of exercise or nitroglycerin do not affect haemodynamics and exercise performance in trained or sedentary individuals   总被引：1，自引：0，他引：1  

Crisafulli A  Melis F  Tocco F  Pittau G  Lorrai L  Gori T  Mancardi D  Concu A  Pagliaro P 《Journal of sports sciences》2007,25(12):1393-1401

Nitroglycerin induces the so-called second window of protection (SWOP), which alleviates myocardial damage and stunning after ischaemia/reperfusion. To determine whether myocardial performance during exercise is improved in the second window of protection, we studied the haemodynamic responses of 12 trained and 11 sedentary individuals during a sequence of maximal tests on a cycle ergometer. A baseline test (basal test) was followed by a second effort performed during the second window of protection (exercise-SWOP test). Haemodynamics was also evaluated after pharmacologically induced SWOP 48 h after transdermal administration of 10 mg of nitroglycerin (pharmacologically induced SWOP test). The exercise-SWOP and pharmacologically induced SWOP tests were separated by a 1-week washout period. Endothelial-dependent vasodilatation after nitroglycerin pre-treatment was also assessed in five sedentary individuals to determine whether nitrate donors could affect vascular function. We found that nitroglycerin pre-treatment did not induce any improvement in haemodynamics in either trained or sedentary individuals, since maximum values of workload, heart rate, stroke volume, cardiac output, myocardial contractility, and double product were similar between the exercise-SWOP and pharmacologically induced SWOP tests in both groups. Furthermore, nitroglycerin pre-treatment did not alter flow-mediated dilation during pharmacologically induced SWOP. Although nitroglycerin pre-treatment alleviates post-ischaemic myocardial stunning, our results suggest that it does not affect the myocardial performance of healthy individuals during exercise performed in the second window of protection, independently of the training status of the individuals. Moreover, nitroglycerin pre-treatment does not ameliorate endothelial function.  相似文献