A mutant of Neurospora crassa deficient in cytochrome c heme lyase activity cannot import cytochrome c into mitochondria

The nuclear cyt-2-1 mutant of Neurospora crassa is characterized by a gross deficiency of cytochrome c (Bertrand, H., and Collins, R. A. (1978) Mol. Gen. Genet. 166, 1-13). The mutant produces mRNA that can be translated into apocytochrome c in vitro. Apocytochrome c is also synthesized in vivo in cyt-2-1, but it is rapidly degraded and thus does not accumulate in the cytosol. Mitochondria from wild-type cells bind apocytochrome c made in vitro from either wild-type or cyt-2-1 mRNA and convert it to holocytochrome c. This conversion depends on the addition of heme by cytochrome c heme lyase and is coupled to translocation of cytochrome c into the intermembrane space. Mitochondria from the cyt-2-1 strain are deficient in the ability to bind apocytochrome c. They are also completely devoid of cytochrome c heme lyase activity. These defects explain the inability of the cyt-2-1 mutant to convert apocytochrome c to the holo form and to import it into mitochondria

Considerations and design on apps for elderly with mild-to-moderate dementia

Many elderly people suffer from dementia in their daily life. The symptoms of dementia include impairments in thinking, communicating and recalling things of the past. Dementia can be caused by brain damage incurred from stroke (brain infarct), injury or other diseases. Recently, research has indicated a potential rehabilitative role for touchscreen technology in dementia. Elders can use apps to aid recall in order to support activities of daily living. Memory and activity apps can be developed for people suffering from early dementia. This paper presents the current state of development in the field of cognitive tests. It has also presented the many considerations and design issues related to the development of apps for people with dementia. © 2015 IEEE.published_or_final_versio

What could be learnt from Positronium for Quarkonium?

In order to fulfill Low's theorem requirements, a new lowest order basis for bound state decay computations is proposed, in which the binding energy is treated non-perturbatively. The properties of the method are sketched by reviewing standard positronium decay processes. Then, it is shown how applying the method to quarkonia sheds new light on some longstanding puzzles.Comment: 12 pages, 10 figures. Talk given at the ETH Workshop on Positronium Physics, May 30-31, 2003, Zurich, Switzerlan

Gender gap in Hong Kong: an update

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Solar neutrino interactions: Using charged currents at SNO to tell neutral currents at Super-Kamiokande

In the presence of flavor oscillations, muon and tau neutrinos can contribute to the Super-Kamiokande (SK) solar neutrino signal through the neutral current process \nu_{\mu,\tau} e^{-}\to \nu_{\mu,\tau} e^{-}. We show how to separate the \nu_e and \nu_{\mu,\tau} event rates in SK in a model independent way, by using the rate of the charged current process \nu_e d \to p p e^{-} from the Sudbury Neutrino Observatory (SNO) experiment, with an appropriate choice of the SK and SNO energy thresholds. Under the additional hypothesis of no oscillations into sterile states, we also show how to determine the absolute ^{8}B neutrino flux from the same data set, independently of the \nu_e survival probability.Comment: 14 pages (RevTeX), incl. 3 figures (epsf), submitted to Phys. ReV.

The Mere Presence of a Cell Phone: Effects on Academic Ability

Prior research has suggested that cell phone use in the classroom and during learning-related tasks is detrimental to academic performance. Recently, the mere presence of a cell phone has been found to negatively affect relationships and to impair performance on learning and cognitive tasks. This study explored whether the presence (visibility without use) of a cell phone negatively impacts one’s performance on tests measuring preexisting academic ability. The study evaluated 45 participants; some were enrolled in an introductory psychology course, and others were members of the public. Three subtests from the Wide Range Achievement Test (WRAT-4) were completed: spelling, sentence comprehension, and mathematics. During testing, half of the participants had cell phones, and the other half did not. Statistical analyses revealed no significant difference between the cell phone-present and cell phone-absent group on the sentence comprehension (p=.52), spelling (p=.07), and mathematics subtest (p=.11). Unexpectedly, a non-significant trend was observed in the opposite direction; that is, the cell phone-present group outperformed the cell phone-absent group on all subtests. Therefore, the original hypothesis suggesting that the cell phone-present group would be significantly poorer at demonstrating preexisting skills on tests of academic ability in comparison to the cell phone-present group was not supported

A Tale of Two [Univer]Cities: Changing Learning Environments

This paper outlines case study developments in relation to new learning environments in two universities in Hong Kong, with an emphasis on the context behind these changes, the changes involved, and the mechanisms employed for informing and guiding these changes. From past to present, the focus of learning has shifted from the search and understanding of information to the application and construction of knowledge (Brown & Long, 2006). The learner-centered paradigm of teaching and learning (e.g. Laurillard 2002 & 2009; Biggs 2003) highlights the importance of engaging students actively in both the manipulation and construction of knowledge. This leads to new interpretations of what constitutes 'good' learning activities, and the process of knowledge acquisition, active learning, interaction and social engagement (Brown & Long 2006). Learning environments have an important role in coordinating and affording different learning activities (Aimee 2009; Brown & Long 2006; Van Note Chism & Bickford 2002; Van Note Chism 2006; Lomas & Oblinger 2006). With an increased emphasis in interactive and collaborative learning, new designs of environments have been demanded. For example, Bransford, Brown and Cocking (2000) called for new research to review physical learning environments in higher education that facilitate group work and the promotion of interaction between students and students, and students and teachers. Learning environments in this paper are divided into two categories: physical and virtual. The physical relates to the buildings, the classrooms, the laboratories, the libraries, the cafés; the formal and inform places where student study and learn. Informal learning spaces or ILS refers to the learning environment that is outside formal facilitation by instructors (Hunley & Schaller 2006), for example, open spaces in corridors or outside classrooms. In addition to lectures in classrooms and studying at libraries, students have always engaged in informal learning activities in other parts of the university campus. Students often engage in deep learning through face-to-face discussions in ILS. In previous university designs, these ILS have often focused on student residences, open areas between buildings where students gather, etc (Jamieson, Dane & Lippman 2005). Wolff (2002), however, points out the importance of focusing on other factors in ILS mostly brought about by new technology affordance and that designing the right ILS can make a major difference in supporting a range of learning activities, both individual and group-based.published_or_final_versio

Enhancing the Critical Current of a Superconducting Film in a Wide Range of Magnetic Fields with a Conformal Array of Nanoscale Holes

The maximum current (critical current) a type-II superconductor can transmit without energy loss is limited by the motion of the quantized magnetic flux penetrating into a superconductor. Introducing nanoscale holes into a superconducting film has been long pursued as a promising way to increase the critical current. So far the critical current enhancement was found to be mostly limited to low magnetic fields. Here we experimentally investigate the critical currents of superconducting films with a conformal array of nanoscale holes that have non-uniform density while preserving the local ordering. We find that the conformal array of nanoscle holes provides a more significant critical current enhancement at high magnetic fields. The better performance can be attributed to its arching effect that not only gives rise to the gradient in hole-density for pinning vortices with a wide range of densities but also prevent vortex channeling occurring in samples with a regular lattice of holes.Comment: 5 pages, 3 figure