Adsorption induced reconstruction of the Cu(110) surface

The formation of the O/Cu(110)-(2 × 1) and H/Cu(110)-(1 × 2) superstructures has been investigated by a LEED beam profile analysis. The oxygen induced reconstruction proceeds at later stages by creation of holes on flat terraces. This could not be observed at the hydrogen induced missing row reconstruction. The formation of the missing row structure proceeds most probably via nucleation at steps and subsequent growth of (1 × 2) islands. The influence of different distributions of steps and islands on beam profiles is discussed

Viewership footprint for a low-resource, student-centred collaborative video platform to teach orthopaedics in southern Africa

Background. Institutions are increasingly using technology to augment the class learning experience of medical students. Especially in Africa, local content is key to allow insights and knowledge to emerge and build transformative capacity for students and patients. There is currently no peer-reviewed video content produced by students with the aim of providing education on orthopaedic topics for medical students and patients in this region.Objectives. To evaluate the demographic and geographical viewership as well as video-specific statistics of orthopaedic teaching videos for medical students on a YouTube channel, with the expressed aim of informing future content production.Methods. Videos were produced by South African (SA) medical students as a problem-based collaborative project. Student-owned smartphones and various types of free video editing software were used to produce these videos, which were then assessed by a group of orthopaedic specialists and uploaded onto a YouTube channel (UCTeach). The analytical reports of this channel generated by Google and YouTube were analysed regarding watch time per day (minutes), average view duration (minutes), most watched videos, top geographies, age and gender.Results. A total of 83 videos were uploaded to the UCTeach Ortho channel during a 2-year period, with a total watch time of 857 062 minutes and 337 983 views. The majority of viewers were between the ages of 18 and 34 years (85%). India had the most views (n=69 089), followed by the USA (n=66 257) and SA (n=21 882). Most of the videos were watched on mobile phones (n=183 299) and computers (n=128 228). The most watched video, produced in April 2016, was on physiological and pathological gait, with 51 314 views.Conclusions. Our study provides proof of concept for a new educational material creation and dissemination strategy. A low-cost local collaborative orthopaedic video project by medical students for medical students can lead to high view counts and watch time on YouTube. It is accessible to audiences in low-, middle- and high-income countries. The students’ educational videos also reached a global audience consistently over a 3-year period

Observations of Buried Lake Drainage on the Antarctic Ice Sheet.

Between 1992 and 2017, the Antarctic Ice Sheet (AIS) lost ice equivalent to 7.6 ± 3.9 mm of sea level rise. AIS mass loss is mitigated by ice shelves that provide a buttress by regulating ice flow from tributary glaciers. However, ice-shelf stability is threatened by meltwater ponding, which may initiate, or reactivate preexisting, fractures, currently poorly understood processes. Here, through ground penetrating radar (GPR) analysis over a buried lake in the grounding zone of an East Antarctic ice shelf, we present the first field observations of a lake drainage event in Antarctica via vertical fractures. Concurrent with the lake drainage event, we observe a decrease in surface elevation and an increase in Sentinel-1 backscatter. Finally, we suggest that fractures that are initiated or reactivated by lake drainage events in a grounding zone will propagate with ice flow onto the ice shelf itself, where they may have implications for its stability

Analytic frameworks for assessing dialogic argumentation in online learning environments

Over the last decade, researchers have developed sophisticated online learning environments to support students engaging in argumentation. This review first considers the range of functionalities incorporated within these online environments. The review then presents five categories of analytic frameworks focusing on (1) formal argumentation structure, (2) normative quality, (3) nature and function of contributions within the dialog, (4) epistemic nature of reasoning, and (5) patterns and trajectories of participant interaction. Example analytic frameworks from each category are presented in detail rich enough to illustrate their nature and structure. This rich detail is intended to facilitate researchers’ identification of possible frameworks to draw upon in developing or adopting analytic methods for their own work. Each framework is applied to a shared segment of student dialog to facilitate this illustration and comparison process. Synthetic discussions of each category consider the frameworks in light of the underlying theoretical perspectives on argumentation, pedagogical goals, and online environmental structures. Ultimately the review underscores the diversity of perspectives represented in this research, the importance of clearly specifying theoretical and environmental commitments throughout the process of developing or adopting an analytic framework, and the role of analytic frameworks in the future development of online learning environments for argumentation

Affordances, constraints and information flows as ‘leverage points’ in design for sustainable behaviour

Copyright @ 2012 Social Science Electronic PublishingTwo of Donella Meadows' 'leverage points' for intervening in systems (1999) seem particularly pertinent to design for sustainable behaviour, in the sense that designers may have the scope to implement them in (re-)designing everyday products and services. The 'rules of the system' -- interpreted here to refer to affordances and constraints -- and the structure of information flows both offer a range of opportunities for design interventions to in fluence behaviour change, and in this paper, some of the implications and possibilities are discussed with reference to parallel concepts from within design, HCI and relevant areas of psychology

NLL soft and Coulomb resummation for squark and gluino production at the LHC

We present predictions of the total cross sections for pair production of squarks and gluinos at the LHC, including the stop-antistop production process. Our calculation supplements full fixed-order NLO predictions with resummation of threshold logarithms and Coulomb singularities at next-to-leading logarithmic (NLL) accuracy, including bound-state effects. The numerical effect of higher-order Coulomb terms can be as big or larger than that of soft-gluon corrections. For a selection of benchmark points accessible with data from the 2010-2012 LHC runs, resummation leads to an enhancement of the total inclusive squark and gluino production cross section in the 15-30 % range. For individual production processes of gluinos, the corrections can be much larger. The theoretical uncertainty in the prediction of the hard-scattering cross sections is typically reduced to the 10 % level.Comment: 45 pages, 16 Figures, LaTex. v2: published version. Grids with numerical results for the NLL cross sections for squark and gluino production at the 7/8 TeV LHC are included in the submission and are also available at http://omnibus.uni-freiburg.de/~cs1010/susy.htm

Brugada syndrome during physical therapy: a case report

This case report describes about a young, male patient with persisting syncope during physical therapy for complex regional pain syndrome type 1 after metatarsal fractures

Sigma-phase in Fe-Cr and Fe-V alloy systems and its physical properties

A review is presented on physical properties of the sigma-phase in Fe-Cr and Fe-V alloy systems as revealed both with experimental -- mostly with the Mossbauer spectroscopy -- and theoretical methods. In particular, the following questions relevant to the issue have been addressed: identification of sigma and determination of its structural properties, kinetics of alpha-to-sigma and sigma-to-alpha phase transformations, Debye temperature and Fe-partial phonon density of states, Curie temperature and magnetization, hyperfine fields, isomer shifts and electric field gradients.Comment: 26 pages, 23 figures and 83 reference

Invasion and MMP expression profile in desmoid tumours

Desmoid tumours are locally invasive soft tissue tumours in which beta-catenin mediated TCF-dependent transcription is activated. The role of soluble factors secreted by the myofibroblastic desmoid tumour, which could stimulate tumour invasiveness, was investigated. Using collagen gel invasion assays, the presence of factors stimulating invasion in desmoid conditioned media (CM) could be established. Since matrix metalloproteinases (MMPs) have been implicated in the process of tumoral invasion, the expression levels of the MMP family members were evaluated. Quantitative reverse transcription-PCR was used to determine the expression levels of MMP1, MMP2, MMP3, MMP7, MMP11, MMP12, MMP13, MMP14 and the inhibitors TIMP1, TIMP2 and TIMP3. Besides overexpression of MMP7, a known TCF-dependent target gene, a striking upregulation of the expression levels of MMP1, MMP3, MMP11, MMP12 and MMP13 in desmoid tumours, compared to unaffected fibroblasts from the same patients, was found. Treating the CM of desmoids with a synthetic and a physiologic MMP inhibitor reduced the invasion-stimulating capacity of the desmoid CM by approximately 50%. These results suggest the involvement of soluble factors, released by the desmoid cells, in stimulating invasion and implicate the MMPs as facilitators of invasion