On a mechanism for enhancing magnetic activity in tidally interacting binaries

We suggest a mechanism for enhancing magnetic activity in tidally interacting binaries. We suppose that the deviation of the primary star from spherical symmetry due to the tidal influence of the companion leads to stellar pulsation in its fundamental mode. It is shown that stellar radial pulsation amplifies torsional Alfv{\'e}n waves in a dipole-like magnetic field, buried in the interior, according to the recently proposed swing wave-wave interaction (Zaqarashvili 2001). Then amplified Alfv{\'e}n waves lead to the onset of large-scale torsional oscillations, and magnetic flux tubes arising towards the surface owing to magnetic buoyancy diffuse into the atmosphere producing enhanced chromospheric and coronal emission.Comment: Accepted in Ap

Promoting Functional Health in Midlife and Old Age: Long-Term Protective Effects of Control Beliefs, Social Support, and Physical Exercise

Previous studies have examined physical risk factors in relation to functional health, but less work has focused on the protective role of psychological and social factors. We examined the individual and joint protective contribution of control beliefs, social support and physical exercise to changes in functional health, beyond the influence of health status and physical risk factors in middle-aged and older adults. Given that functional health typically declines throughout adulthood, it is important to identify modifiable factors that can be implemented to maintain functioning, improve quality of life, and reduce disability.We conducted a national longitudinal study, Midlife in the United States (MIDUS), with assessments in 1995-1996 and 2004-2006, and 3,626 community-residing adults, aged 32 to 84, were included in the analyses. Functional health (Physical Functioning subscale of the SF-36) and protective factors were measured at both occasions. While controlling for socio-demographic, health status, and physical risk factors (large waist circumference, smoking, and alcohol or drug problems), a composite of the three protective variables (control beliefs, social support, and physical exercise) at Time 1 was significantly related to functional health change. The more of these factors at Time 1, the better the health maintenance over 10 years. Among middle-aged and older adults, declines in health were significantly reduced with an increased number of protective factors.Age-related declines in health were reduced among those with more protective factors up to a decade earlier in life. Modifiable psychological, social, and physical protective factors, individually and in the aggregate, are associated with maintenance of functional health, beyond the damaging effects of physical risk factors. The results are encouraging for the prospect of developing interventions to promote functional health and for reducing public health expenditures for physical disability in later life

Search for the Structure of a Sulfur-Induced Reconstruction on Cu(111)

We have carried out an extensive DFT-based search for the structure of the (√43 × √43)R ± 7.5° reconstruction of S on Cu(111), which exhibits a honeycombtype structure in scanning tunneling microscopy (STM). We apply two criteria in this search: The structure must have a reasonably low chemical potential, and it must provide a good match with STM data, both our own and the data published by Wahlström et al. Phys. Rev. B 1999, 60, 10699. The best model has 12 S adatoms and 9 Cu adatoms per unit cell. Local defects within the Cu9S12 framework, consisting of one missing or one extra Cu adatom per unit cell, would be difficult to detect with STM and would not be energetically costly. There is no obvious correlation between this model and the structure of bulk CuS. If the √43 reconstruction is viewed in terms of local building blocks, then CuS3 and CuS2 clusters, linked by shared S atoms, provides the best description.Reprinted (adapted) with permission from Journal of Physical Chemistry C 118 (2014): 29218, doi: 10.1021/jp505351g. Copyright 2014 American Chemical Society.</p

Surveying the technology landscape: Teachers' use of technology in secondary mathematics classrooms

For many years, education researchers excited by the potential for digital technologies to transform mathematics teaching and learning have predicted that these technologies would become rapidly integrated into every level of education. However, recent international research shows that technology still plays a marginal role in mathematics classrooms. These trends deserve investigation in the Australian context, where over the past 10 years secondary school mathematics curricula have been revised to allow or require use of digital technologies in learning and assessment tasks. This article reports on a survey of mathematics teachers' use of computers, graphics calculators, and the Internet in Queensland secondary schools, and examines relationships between use and teachers' pedagogical knowledge and beliefs, access to technology, and professional development opportunities. Although access to all forms of technology was a significant factor related to use, teacher beliefs and participation in professional development were also influential. Teachers wanted professional development that modelled planning and pedagogy so they could meaningfully integrate technology into their lessons in ways that help students learn mathematical concepts. The findings have implications not only for resourcing of schools, but also for designing professional development that engages teachers with technology in their local professional contexts. [Author abstract