6,361 research outputs found
Students' teaching career expectations by gender and ability levels in science and math: The role of salary and numeracy skills
Understanding what factors foster young people's aspirations to work as teachers is critical for designing effective recruitment policies, and for ensuring that enough youngsters enter the teaching profession. We examine what factors explain between‐country differences in the percentage of 15‐year‐old students who expect to work as teachers as adults. We focus on two factors: (1) the salaries teachers can expect to earn compared to professionals in science, technology, engineering and mathematics (STEM); and (2) the skill levels teachers have compared to STEM professionals. Relative salaries indicate if (and to what extent) the financial returns associated with teaching careers are higher or lower than professional STEM careers dominated by men. Relative skills highlight the investment in human capital that teachers are expected to make to be able to enter the profession, as well as the social and cultural status that is associated with teaching. We used data from 29 countries that participated in the Programme for International Student Assessment and the Programme for International Assessment of Adult Competencies. In countries where teacher salaries and numeracy skills were high compared to those commanded by STEM professionals, gender gaps in teaching career expectations were smaller. High‐ability students in science and mathematics were more likely to expect to work as teachers in countries where teachers have comparatively higher numeracy skills. Our findings show that when teacher salaries are competitive in relationship to the salaries of STEM professionals, more students overall expect to work as teachers. However, whilst low‐ and middle‐performing students in science and mathematics were attracted by economic incentives, high‐performing students in science and mathematics were not
Gender disparities in fear of failure among 15-year-old students: The role of gender inequality, the organisation of schooling and economic conditions
INTRODUCTION: Prior research indicates that female students express higher fear of failure than male students and that fear of failure is associated with lower social and emotional well-being and higher levels of stress, anxiety, burnout and depression. Fear of failure also leads individuals to limit their choices and take fewer risks than would be warranted given their ability and context to minimise the possibility of failing. METHODS: We examined cross-country differences in gender gaps in fear of failure as well as factors that explain gender gaps and variations of gender gaps across countries using multilevel modelling techniques. Participants were 517,047 15-year-old students from 59 countries who took part in the 2018 Programme for International Student Assessment (PISA). RESULTS: Within countries, students with higher reading achievement and who lacked a growth mindset reported higher fear of failure. The gender gap in fear of failure was especially high among high-achieving students and students with high-achieving peers. The size of the gender gap in fear of failure differed across countries: it was higher in countries with higher levels of economic prosperity, with lower levels of societal-level gender inequality and countries with comprehensive education systems. CONCLUSIONS: The greater prevalence of fear of failure among female students among high-achieving students attending high-achieving schools in prosperous and more gender equal societies could help to explain the paradox of the persistent underrepresentation of females in certain occupations in contexts that are most supportive of females
Why don't more boys want to become teachers? The effect of a gendered profession on students’ career expectations
Gender differences in teaching career expectations were explored among 15-year-old students in 49 countries participating in the 2015 cycle of the Programme for International Student Assessment (PISA). Results revealed that boys were generally less likely than girls to expect to work as teachers, but the magnitude of the gender gap varied across countries. Boys were more likely to expect to work as teachers in countries with a greater representation of male teachers and in countries with higher teacher salaries. In countries with more egalitarian gender beliefs (i.e., beliefs and attitudes toward gender equality), both boys and girls were less likely to expect teaching careers, but this negative association was stronger for boys than for girls
Energetics of large carbon clusters: Crossover from fullerenes to nanotubes
The energetics of large-sized fullerenes and carbon nanotubes is investigated through first-principles pseudopotential calculations for the carbon cluster of CN (60???N???540). The strain energy due to the presence of pentagons, in addition to the curvature effect, makes an important contribution to the energetics of the fullerenes and nanotubes and accurately describes the N dependence of the energy of the spherical fullerenes. Our model predicts that a nanotube of ??? 13 A in diameter [for example, a (9,9) or (10,10) tube] is energetically most stable among various single-walled nanotubes and fullerenes, consistent with many experimental observations.open252
Magnetic ordering at the edges of graphitic fragments: Magnetic tail interactions between the edge-localized states
To understand the formation mechanism of magnetic moments at the edges of graphitic fragments, we carry out first-principles density-functional calculations for the electronic and magnetic structures of graphitic fragments with various spin and geometric configurations. We find that interedge and interlayer interactions between the localized moments can be explained in terms of interactions between the magnetic tails of the edge-localized states. In addition, the dihydrogenated edge states as well as Fe ad-atoms at the edge are studied in regard to the magnetic order and proximity effects.open28621
Local structure around Ga in ultrafine GaN/ZnO coaxial nanorod heterostructures
The structure of tubular GaN coaxially grown on ZnO nanorods with thickness of 6-12 nm was investigated using x-ray absorption fine structure (XAFS) at the Ga K edge. The XAFS measurements revealed that the GaN had a distorted-wurtzite structure, and that there were more distortions in the bond length of Ga-Ga pairs than in Ga-N pairs. However, no extra disorders were observed in any of the pairs. These results strongly suggest that Ga atoms first bonded to the ZnO template. Unlike other techniques, the XAFS determines structure around a selected species atom in nano-heterostructures. (c) 2006 American Institute of Physics.open1188sciescopu
Orientation-dependent x-ray absorption fine structure of ZnO nanorods
The local structure of two samples of vertically well-aligned ZnO nanorods with average diameters of 13 and 37 nm were studied using orientation-dependent x-ray absorption fine structure (XAFS) at the Zn K edge. The aligned ZnO nanorod samples were fabricated on sapphire (0001) substrates with a catalyst-free metalorganic vapor-phase epitaxy method. The XAFS measurements showed that both nanorod samples have a well-ordered wurtzite structure and that no vacancy was observed at either site of zinc or oxygen atoms. However, we found that in both samples the lattice constants of a and b were shrunken by similar to0.04 Angstrom while c was elongated by similar to0.1 Angstrom, compared with those of their bulk counterparts. Furthermore, there was a substantial amount of disorder in the bond length of the only Zn-O pairs located near the ab plane. This may suggest that the terminating atoms at the boundaries of the nanorods are oxygen atoms. (C) 2005 American Institute of Physics.open114545sciescopu
Microscopic mechanism of fullerene fusion
Combining total energy calculations with a search of phase space, we investigate the microscopic fusion mechanism of C60 fullerenes. We find that the (2 + 2) cycloaddition reaction, a necessary precursor for fullerene fusion, may be accelerated inside a nanotube. Fusion occurs along the minimum energy path as a finite sequence of Stone-Wales transformations, determined by a graphical search program. Search of the phase space using the "string method" indicates that Stone-Wales transformations are multistep processes, and provides detailed information about the transition states and activation barriers associated with fusion.open413
Intrathecal injection of human umbilical cord blood-derived mesenchymal stem cells for the treatment of basilar artery dissection: a case report
<p>Abstract</p> <p>Introduction</p> <p>Basilar artery dissection is a rare occurrence, and is significantly associated with morbidity and mortality. To the best of our knowledge, we report the first case of basilar artery dissection treated with mesenchymal stem cells.</p> <p>Case presentation</p> <p>We present the case of a 17-year-old Korean man who was diagnosed with basilar artery dissection. Infarction of the bilateral pons, midbrain and right superior cerebellum due to his basilar artery dissection was partially recanalized by intrathecal injection of human umbilical cord blood-derived mesenchymal stem cells. No immunosuppressants were given to our patient, and human leukocyte antigen alloantibodies were not detected after cell therapy.</p> <p>Conclusions</p> <p>This case indicates that intrathecal injections of mesenchymal stem cells can be used in the treatment of basilar artery dissection.</p
- …