A Mechanism for Cutting Carbon Nanotubes with a Scanning Tunneling Microscope

We discuss the local cutting of single-walled carbon nanotubes by a voltage pulse to the tip of a scanning tunneling microscope. The tip voltage ($\mid V \mid \ge$~3.8 eV) is the key physical quantity in the cutting process. After reviewing several possible physical mechanisms we conclude that the cutting process relies on the weakening of the carbon-carbon bonds through a combination of localized particle-hole excitations induced by inelastically tunneling electrons and elastic deformation due to the electric field between tip and sample. The carbon network releases part of the induced mechanical stress by forming topological defects that act as nucleation centers for the formation of dislocations that dynamically propagate towards bond-breaking.Comment: 7 pages, 6 postscript figures, submitted to PR

Offshore education : offshore education in the wider context of internationalisation and ICT: experiences and examples from Dutch higher education

This report presents a study on offshore education conducted by a consortium of Dutch higher education researchers and commissioned by the Digital University (DU). The study explored the extent to which Dutch higher education institutions are involved in offering their educational services abroad (offshore education). After thoroughly embedding offshore education in the wider contexts of internationalisation and ICT policies, the study particularly explores the practical experiences with a number of real-life offshore activities of Dutch higher education. As a warm-up to this report, a few interesting cases are briefly touched upon below

Framing the Immigration Policy Agenda: A Qualitative Comparative Analysis of Media Effects on Dutch Immigration Policies

This study applies a qualitative comparative analysis (QCA) design to examine how configurations of quantitative and qualitative aspects of media coverage associate with changes on the policy agenda. We analyze media coverage of sixteen focusing events related to Dutch immigration policies—an intractable policy controversy that is regularly under media scrutiny. In addition to the quantity of media attention, we take into account whether dominant framing in media coverage is contesting the current policy frame and whether the framing in the media is consonant. Our analysis indicates that frame contestation is a necessary condition for media effects. Quantity of media attention and frame consonance are relevant indicators of changes on the policy agenda only when the majority of media coverage is contesting the current policy frame. Furthermore, we found that in the case of intractable policy controversies, media f

A 100 mW monolithic Yb waveguide laser fabricated using the femtosecond laser direct-write technique

A femtosecond laser-written monolithic waveguide laser (WGL) oscillator based on a distributed feedback (DFB) architecture and fabricated in ytterbium doped phosphate glass is reported. The device lased at 1033 nm with an output power of 102 mW and a bandwidth less than 2 pm when bidirectionally pumped at 976 nm. The WGL device was stable and operated for 50 hours without degradation. This demonstration of a high performance WGL opens the possibility for creating a variety of narrow-linewidth laser designs in bulk glasses.Comment: 5 pages, 3 figures, submitted journal manuscrip

Risk of postoperative acute kidney injury in patients undergoing orthopaedic surgery—development and validation of a risk score and effect of acute kidney injury on survival:observational cohort study

Funding: This study was funded by Tenovus Tayside, Chief Scientist Office, Scotland and a travelling fellowship from the Royal College of Physicians and Surgeons of Glasgow. The funders had no role in the study design; collection, analysis, and interpretation of the data; writing of the report; or the decision to submit the article for publication. The researchers are independent of the funders.Non peer reviewedPublisher PD

Inflammation and premature aging in advanced chronic kidney disease

Systemic inflammation in end-stage renal disease (ESRD) is an established risk factor for mortality and a catalyst for other complications which are related to a premature aging phenotype, including muscle wasting, vascular calcification and other forms of premature vascular disease, depression, osteoporosis and frailty. Uremic inflammation is also mechanistically related to mechanisms involved in the aging process, such as telomere shortening, mitochondrial dysfunction, and altered nutrient sensing, which can have direct effect on cellular and tissue function. In addition to uremia-specific causes such as abnormalities in the phosphate- Klotho axis, there are remarkable similarities between the pathophysiology of uremic inflammation and so-called "inflammaging" in the general population. Potentially relevant, but still somewhat unexplored in this respect are abnormal or misplaced protein structures as well as abnormalities in tissue homeostasis, which evoke danger signals through damage associated molecular patters (DAMPS) as well as the senescence associated secretory phenotype (SASP). Systemic inflammation, in combination with the loss of kidney function, can impair the resilience of the body to external and internal stressors by reduced functional and structural tissue reserve, and by impairing normal organ crosstalk, thus providing an explanation for the greatly increased risk of homeostatic breakdown in this population. In this review, the relation between uremic inflammation and a premature aging phenotype, as well as potential causes and consequences are discussed

e-Learning cookbook. TPACK in professional development in higher education

Information and communication technology (ICT) makes it possible to bring information to everyone who wants to learn. Rapid advances in technology offer strong support for using ICT in teaching. Online education can intensify and improve students' learning process, and enables us to reach more students than by traditional means. The number of courses and modules being offered online is increasing rapidly worldwide. Although online education can reach more people nowadays and new and challenging learning experiences can be created with it, in the average university course the digital dimension too often remains limited to simply publishing the existing face-to-face course content online. It is crucial that lecturers have and can obtain knowledge about how to design technology-enhanced teaching. Technical advances can be expected to continue in the future, and those who wish to implement educational technology in their own teaching practice must reckon on becoming lifelong learners. This fits the culture of academic teachers perfectly: they are already lifelong learners and creators of new knowledge within their discipline. This book is based on the notion that a lecturer who uses ICT in teaching must learn how to apply his or her knowledge about content, pedagogy and technology in an integrated manner. The idea of integrating these three types of knowledge is based on the TPACK model, which stands for Technological Pedagogical Content Knowledge model. The material for this book was developed in a Dutch higher education innovation project known as MARCHET (Make Relevant Choices in Educational Technology, MARCHET, 2009-2011)

The online world as a means of connection and disconnection during the COVID-19 pandemic: A test of the interpersonal-connections-behaviour framework

BACKGROUND: The interpersonal-connections-behaviour framework proposes that social media is helpful/unhelpful to the individual to the extent that it facilitates/hinders satisfaction of core needs for acceptance and belonging (connecting and disconnecting pathways). However, little research has, to date, explicitly tested this framework. METHODS: Both pathways were explored in a cross-sectional sample of UK adults at the start of the pandemic (N = 632) and in longitudinal (cross-lagged) analyses (N = 227-240). Participants completed measures of online and offline socialising with friends and family (connecting pathway), and online and offline social comparisons (disconnecting pathway), anxiety, depression and loneliness. RESULTS: In cross-sectional analyses higher levels of online comparisons were associated with poorer mental health, an effect that survived after controlling for offline comparisons, and was partially mediated by loneliness. Counter to our predictions, online socialising was also associated with poorer mental health. Longitudinal analyses did not support predicted directions of causality. LIMITATIONS: Limitations include a lack of testing of individual-level moderators, the use of single item questions to probe some constructs, and an inability to test for effects potentially operating at different time-scales. CONCLUSIONS: The findings reported partially support the interpersonal-connections-behaviour framework in highlighting a disconnecting (but not connecting) pathway between online engagement and mental health. From a clinical perspective they highlight the importance of including people's online lives when considering mental health risk and resilience, particularly (one might argue) during periods of social isolation

Energy exchange between two orthogonally polarized waves by cascading of two quasi-phase-matched quadratic processes

We demonstrate energy exchange between two orthogonally polarized optical waves as a consequence of a two-color multistep parametric interaction. The energy exchange results from cascading of two quasi-phase-matched (QPM) second-harmonic parametric processes, and it is intrinsically instantaneous. The effect is observed when both the type-I (ooe) second-harmonic generation process and higher QPM order type-0 (eee) second-harmonic generation processes are phase-matched simultaneously in a congruent periodically-poled lithium niobate crystal. The two second-harmonic generation processes share a common secondharmonic wave which couple the two cross-polarized fundamental components and facilitate an energy flow between them. We demonstrate a good agreement between the experimental data and the results of numerical simulations