1,292 research outputs found
Consideration of permanent tidal deformation in the orbit determination and data analysis for the Topex/Poseidon mission
The effects of the permanent tidal effects of the Sun and Moon with specific applications to satellite altimeter data reduction are reviewed in the context of a consistent definition of geoid undulations. Three situations are applicable not only for altimeter reduction and geoid definition, but also for the second degree zonal harmonic of the geopotential and the equatorial radius. A recommendation is made that sea surface heights and geoid undulations placed on the Topex/Poseidon geophysical data record should be referred to the mean Earth case (i.e., with the permanent effects of the Sun and Moon included). Numerical constants for a number of parameters, including a flattening and geoid geopotential, are included
Implementing AcaWriter as a Novel Strategy to Support Pharmacy Students’ Reflective Practice in Scientific Research
Objective. To explore pharmacy students’ perceptions of a novel web application tool (AcaWriter) implemented in a Master of Pharmacy curriculum to support reflective thinking in scientific research. Methods. A qualitative research design involving a 50-minute focus group (n=12) was used. The focus group session was audio-taped, transcribed verbatim, and analyzed thematically using the Braun and Clarke framework. Results. Analysis generated four themes related to AcaWriter’s utility in enhancing students’ research thinking and capacity. The themes identified included: ease of use to prompt reflection, tangible tool with non-judgmental capacity; benefits for enhancing self and peer reflection on research techniques and group dynamics; benefits of the reflective writing process to enhance research capacity compared with engaging in reflective dialogue; and benefits beyond the writing process: cultivating self-improvement and self-confidence. Conclusion. The findings of this study show that a novel web application implemented within a pharmacy curriculum can assist students’ self and peer reflection on a research task. Further research is needed to explore the impact of using this tool and its relationship with academic performance and outcomes
Scaffolding School Pupils’ Scientific Argumentation with Evidence-Based Dialogue Maps
This chapter reports pilot work investigating the potential of Evidence-based Dialogue Mapping to scaffold young teenagers’ scientific argumentation. Our research objective is to better understand pupils’ usage of dialogue maps created in Compendium to write scientific ex-planations. The participants were 20 pupils, 12-13 years old, in a summer science course for “gifted and talented” children in the UK. Through qualitative analysis of three case studies, we investigate the value of dialogue mapping as a mediating tool in the scientific reasoning process during a set of learning activities. These activities were published in an online learning envi-ronment to foster collaborative learning. Pupils mapped their discussions in pairs, shared maps via the online forum and in plenary discussions, and wrote essays based on their dialogue maps. This study draws on these multiple data sources: pupils’ maps in Compendium, writings in science and reflective comments about the uses of mapping for writing. Our analysis highlights the diversity of ways, both successful and unsuccessful, in which dialogue mapping was used by these young teenagers
Decoupled Lithospheric Folding, Lower Crustal Flow Channels, and the Growth of Tibetan Plateau
The growth mechanism of the Tibetan Plateau, postulated by a number of hypotheses, remains
under intense debate. Our analysis of recent satellite-based gravity model reveals that Tibetan lithosphere has
been decoupled and folded. It is further evidenced by the existence of crustal melts and channel flow that have
been observed by seismic and magnetotelluric explorations. Based on 3D geodynamic simulations, we elucidate
the exact buckling structures in the upper crust and lithospheric mantle: at mixed wavelengths between ∼240
and ∼400 km, the lower crustal viscosity is smaller than ∼10 19 Pa·s, implicating weak lower crustal flow
beneath the Plateau. This mixed wavelength is consistent with the result of our inverse gravity modeling. Our
results facilitate a new plausible hypothesis that the decoupled lithospheric folding mechanism can explain the
growth mechanism of the anomalously thick and wide Tibetan Plateau by conflating our idea and contemporary
hypothesized scientific findings
Moho topography, ranges and folds of Tibet by analysis of global gravity models and GOCE data
The determination of the crustal structure is essential in geophysics, as it gives insight into the
geohistory, tectonic environment, geohazard mitigation, etc. Here we present the latest advance
on three-dimensional modeling representing the Tibetan Mohorovi\u10di\u107 discontinuity (topography and
ranges) and its deformation (fold), revealed by analyzing gravity data from GOCE mission. Our study
shows noticeable advances in estimated Tibetan Moho model which is superior to the results using
the earlier gravity models prior to GOCE. The higher quality gravity field of GOCE is reflected in the
Moho solution: we find that the Moho is deeper than 65 km, which is twice the normal continental
crust beneath most of the Qinghai-Tibetan plateau, while the deepest Moho, up to 82 km, is located
in western Tibet. The amplitude of the Moho fold is estimated to be ranging from 129 km to 9 km
with a standard deviation of ~2 km. The improved GOCE gravity derived Moho signals reveal a clear
directionality of the Moho ranges and Moho fold structure, orthogonal to deformation rates observed
by GPS. This geophysical feature, clearly more evident than the ones estimated using earlier gravity
models, reveals that it is the result of the large compressional tectonic process
Randomized Crossover Study Showing Nurse-Led Same Day Review Replacing Next Day Review in Uneventful Phacoemulsification to Be Safe and Efficacious
Purpose. To study whether nurse led same-day review (SDR) after uneventful phacoemulsification can replace next-day review (NDR) in terms of safety and efficacy. Setting. Patients are recruited from an ophthalmology outpatient clinic in Hong Kong. Design. A prospective, randomized crossover study conducted from November 2012 to 2014. Methods. Inclusion criteria include cataract surgery naïve patients undergoing phacoemulsification under local anaesthesia. All patients were seen by our ophthalmic nurse 2 hours after surgery. Before undergoing phacoemulsification of the first eye, patients were randomized to be reviewed on day 1 or 7 after surgery. Surgeons and reviewing doctors were blinded to patient allocation. For the patients’ second eye surgery, group allocation will cross over. Primary outcome measures include visual improvement and patient satisfaction questionnaire. Other measures include cataract characteristics, surgical details, and complications. Statistical tests include paired t-test, Wilcoxon signed rank test, and Chi-square test. Results. 164 eyes from 82 patients were available. Visual improvement, satisfaction, and complications were comparable between both groups. Conclusions. A nurse led SDR can replace NDR in uneventful phacoemulsification in terms of safety and efficacy. Patient satisfaction is also comparable in the setting of Asian culture and when transportation is not a major concern
Contested Collective Intelligence: rationale, technologies, and a human-machine annotation study
We propose the concept of Contested Collective Intelligence (CCI) as a distinctive subset of the broader Collective Intelligence design space. CCI is relevant to the many organizational contexts in which it is important to work with contested knowledge, for instance, due to different intellectual traditions, competing organizational objectives, information overload or ambiguous environmental signals. The CCI challenge is to design sociotechnical infrastructures to augment such organizational capability. Since documents are often the starting points for contested discourse, and discourse markers provide a powerful cue to the presence of claims, contrasting ideas and argumentation, discourse and rhetoric provide an annotation focus in our approach to CCI. Research in sensemaking, computer-supported discourse and rhetorical text analysis motivate a conceptual framework for the combined human and machine annotation of texts with this specific focus. This conception is explored through two tools: a social-semantic web application for human annotation and knowledge mapping (Cohere), plus the discourse analysis component in a textual analysis software tool (Xerox Incremental Parser: XIP). As a step towards an integrated platform, we report a case study in which a document corpus underwent independent human and machine analysis, providing quantitative and qualitative insight into their respective contributions. A promising finding is that significant contributions were signalled by authors via explicit rhetorical moves, which both human analysts and XIP could readily identify. Since working with contested knowledge is at the heart of CCI, the evidence that automatic detection of contrasting ideas in texts is possible through rhetorical discourse analysis is progress towards the effective use of automatic discourse analysis in the CCI framework
Misregulation of mitochondria-lysosome contact dynamics in Charcot-Marie-Tooth Type 2B disease Rab7 mutant sensory peripheral neurons
Inter-organelle contact sites between mitochondria and lysosomes mediate the crosstalk and bidirectional regulation of their dynamics in health and disease. However, mitochondria-lysosome contact sites and their misregulation have not been investigated in peripheral sensory neurons. Charcot-Marie-Tooth type 2B disease is an autosomal dominant axonal neuropathy affecting peripheral sensory neurons caused by mutations in the GTPase Rab7. Using live super-resolution and confocal time-lapse microscopy, we showed that mitochondria-lysosome contact sites dynamically form in the soma and axons of peripheral sensory neurons. Interestingly, Charcot-Marie-Tooth type 2B mutant Rab7 led to prolonged mitochondria-lysosome contact site tethering preferentially in the axons of peripheral sensory neurons, due to impaired Rab7 GTP hydrolysis-mediated contact site untethering. We further generated a Charcot-Marie-Tooth type 2B mutant Rab7 knock-in mouse model which exhibited prolonged axonal mitochondria-lysosome contact site tethering and defective downstream axonal mitochondrial dynamics due to impaired Rab7 GTP hydrolysis as well as fragmented mitochondria in the axon of the sciatic nerve. Importantly, mutant Rab7 mice further demonstrated preferential sensory behavioral abnormalities and neuropathy, highlighting an important role for mutant Rab7 in driving degeneration of peripheral sensory neurons. Together, this study identifies an important role for mitochondria-lysosome contact sites in the pathogenesis of peripheral neuropathy
Disruption of MEF2C signaling and loss of sarcomeric and mitochondrial integrity in cancer-induced skeletal muscle wasting
Cancer cachexia is a highly debilitating paraneoplastic disease observed in more than 50% of patients with advanced cancers and directly contributes to 20% of cancer deaths. Loss of skeletal muscle is a defining characteristic of patients with cancer cachexia and is associated with poor survival. The present study reveals the involvement of a myogenic transcription factor Myocyte Enhancer Factor (MEF) 2C in cancer-induced skeletal muscle wasting. Increased skeletal muscle mRNA expression of Suppressor of Cytokine Signaling (Socs) 3 and the IL-6 receptor indicative of active IL-6 signaling was seen in skeletal muscle of mice bearing the Colon 26 (C26) carcinoma. Loss of skeletal muscle structural integrity and distorted mitochondria were also observed using electron microscopy. Gene and protein expression of MEF2C was significantly downregulated in skeletal muscle from C26-bearing mice. MEF2C gene targets myozenin and myoglobin as well as myokinase were also altered during cachexia, suggesting dysregulated oxygen transport capacity and ATP regeneration in addition to distorted structural integrity. In addition, reduced expression of calcineurin was observed which suggested a potential pathway of MEF2C dysregulation. Together, these effects may limit sarcomeric contractile ability and also predispose skeletal muscle to structural instability; associated with muscle wasting and fatigue in cachexia
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