The Impact Of Student Mindsets In The Virtual Math Classroom

Mindset has been studied in multiple traditional school settings, but its interaction with transactional distance in a virtual school environment is missing from the current research. This dissertation explores the experiences of students and learning coaches in a virtual high school through a series of interviews in order to present a better understanding of how students and learning coaches perceive the role of mindset and transactional distance in their interactions with each other, the content, and the teacher. The case study design applied the lenses of Transactional Distance Theory and Mindset Theory to descriptive coding of interview transcripts and relevant documents and concluded that transactional distance, while at least partially constructed by the student and enabled by the learning coach, contributes to the student’s sense of isolation, the student’s reliance on the learning coach, the increased need for a student to be able to function autonomously and exhibit a growth mindset, and the increased demands on the learning coach above what was initially intended in the virtual model design for that role

Human‐initiated autocyclic delta failures

River regulations have resulted in changes in the hydrology and particle bud- gets of fluvial systems. Since the 19th century, many rivers have been signifi- cantly modified to control flood hazards, to gain land from swamp areas for agricultural purposes, and to stabilize river-levels and lake-levels to facilitate navigation. These dramatic changes of the river courses have impacted the sediment budgets and grain-size dissemination along them as well as the sedi- ment distribution at the delta mouths in the downstream lakes, which could lead to slope instabilities. Deposits of such catastrophic lacustrine mass move- ments caused by delta collapses have been, for instance, observed in Lake Bri- enz (Switzerland), where relatively thick (0.5 to 1.3 m) and voluminous (>1 million m3) megaturbidites are stacked in the deep basin witnessing these pro- cesses. This study uses sediment cores and seismic data to reconstruct the megaturbidites’ history in Lake Brienz. Data reveal that mass-movement deposits, originating from the Aare Delta, one of the two main inflows, have mean ages of 1853, 1905, 1942 and 1996 CE and that they were unprecedented in, at least, half a millennium. The fact that the numbers of floods and earth- quakes have not changed radically over this time period implies that human impact is the most likely explanation for these failure events. Therefore, the recurrent delta collapses are attributed to the focused sediment accumulation at the front of the channelized inflow in the proximal delta region, caused by the modification of the Aare River through its straightening and channeliza- tion during the late 19th century. These findings indicate that river regulation can affect delta sedimentation, leading to autocyclic delta collapses. Those collapses, in turn, can potentially generate tsunami waves, representing an additional natural hazard for shoreline communities

Traces of a prehistoric and potentially tsunamigenic mass movement in the sediments of Lake Thun (Switzerland).

Mass movements constitute major natural hazards in the Alpine realm. When triggered on slopes adjacent to lakes, these mass movements can generate tsunami-like waves that may cause additional damage along the shore. For hazard assessment, knowledge about the occurrence, the trigger and the geomechanical and hydrogeological mechanisms of these mass movements is necessary. For reconstructing mass movements that occurred in or adjacent to lakes, the lakes's sedimentary record can be used as an archive. Here, we present a prehistorical mass-movement event, of which the traces were found in an alpine lake, Lake Thun, in central Switzerland. The mass movement is identified by large blocks on the bathymetric map, a chaotic to transparent facies on the reflection seismic profiles, and by a mixture of deformed lake sediments and sandy organic-rich layers in the sediment-core record. The event is dated at 2642-2407 cal year BP. With an estimated volume of ~ 20 × 106 m3 it might have generated a wave with an initial amplitude of > 30 m. In addition to this prehistorical event, two younger deposits were identified in the sedimentary record. One could be dated at 1523-1361 cal year BP and thus can be potentially related to an event in 598/599 AD documented in historical reports. The youngest deposit is dated at 304-151 cal year BP (1646-1799 AD) and is interpreted to be related to the artificial Kander river deviation into Lake Thun (1714 AD). Supplementary Information The online version contains supplementary material available at 10.1186/s00015-022-00405-0

Geotechnical characterization and stability analysis of subaqueous slopes in Lake Lucerne (Switzerland).

Tsunamis occur not only in marine settings but also in lacustrine environments. Most of the lacustrine tsunamis are caused by seismically- or aseismically-triggered mass movements. Therefore, an assessment of the stability of subaqueous slopes is crucial for tsunami hazard assessment in a lake. We selected Lake Lucerne (Switzerland) as a natural laboratory to perform an in-depth geotechnical characterization of its subaqueous slopes. This lake experienced documented tsunamis in 1601 and 1687. Some of its slopes still bear sediment volumes with a potential for tsunamigenic failure. To identify such slopes, we interpreted available reflection seismic data and analyzed the bathymetric map. Then, we performed 152 dynamic Cone Penetration Tests with pore pressure measurement (CPTu) and retrieved 49 sediment cores at different locations in the lake. These data were used to characterize the failure-prone sediments and to evaluate the present-day static stability of subaqueous slopes. Obtained results allowed the definition of three classes of slopes in terms of static stability: unstable slopes, stable slopes close to the unstable state, and stable areas. Non-deltaic slopes with thicker unconsolidated fine-grained sediment drape and moderate-to-high slope gradients (> 5-10°) have the lowest Factor of Safety. In agreement with previous studies, the failure plane for the non-deltaic slopes is embedded within the fine-grained glaciolacustrine sediments. Deltaic slopes with prevailing coarse-grained sediments mostly appear statically stable. Finally, we generalized the measured undrained shear strength profiles into the depth-dependent power-law models. These models define the of Lake Lucerne's sediments and can be applied to other lakes with similar sedimentation history. Supplementary Information The online version contains supplementary material available at 10.1007/s11069-022-05310-1

A Simplified Classification of the Relative Tsunami Potential in Swiss Perialpine Lakes Caused by Subaqueous and Subaerial Mass-Movements

Historical reports and recent studies have shown that tsunamis can also occur in lakes where they may cause large damages and casualties. Among the historical reports are many tsunamis in Swiss lakes that have been triggered both by subaerial and subaqueous mass movements (SAEMM and SAQMM). In this study, we present a simplified classification of lakes with respect to their relative tsunami potential. The classification uses basic topographic, bathymetric, and seismologic input parameters to assess the relative tsunami potential on the 28 Swiss alpine and perialpine lakes with a surface area >1km2. The investigated lakes are located in the three main regions “Alps,” “Swiss Plateau,” and “Jura Mountains.” The input parameters are normalized by their range and a k-means algorithm is used to classify the lakes according to their main expected tsunami source. Results indicate that lakes located within the Alps show generally a higher potential for SAEMM and SAQMM, due to the often steep surrounding rock-walls, and the fjord-type topography of the lake basins with a high amount of lateral slopes with inclinations favoring instabilities. In contrast, the missing steep walls surrounding lakeshores of the “Swiss Plateau” and “Jura Mountains” lakes result in a lower potential for SAEMM but favor inundation caused by potential tsunamis in these lakes. The results of this study may serve as a starting point for more detailed investigations, considering field data

Gefahrenabschätzung von durch Unterwasserhangrutschungen ausgelösten Tsunamis in Seen

Aufsatz veröffentlicht in: "Wasserbau-Symposium 2021: Wasserbau in Zeiten von Energiewende, Gewässerschutz und Klimawandel, Zurich, Switzerland, September 15-17, 2021, Band 1" veröffentlicht unter: https://doi.org/10.3929/ethz-b-00049975

Toward a common standard for data and specimen provenance in life sciences

Open and practical exchange, dissemination, and reuse of specimens and data have become a fundamental requirement for life sciences research. The quality of the data obtained and thus the findings and knowledge derived is thus significantly influenced by the quality of the samples, the experimental methods, and the data analysis. Therefore, a comprehensive and precise documentation of the pre-analytical conditions, the analytical procedures, and the data processing are essential to be able to assess the validity of the research results. With the increasing importance of the exchange, reuse, and sharing of data and samples, procedures are required that enable cross-organizational documentation, traceability, and non-repudiation. At present, this information on the provenance of samples and data is mostly either sparse, incomplete, or incoherent. Since there is no uniform framework, this information is usually only provided within the organization and not interoperably. At the same time, the collection and sharing of biological and environmental specimens increasingly require definition and documentation of benefit sharing and compliance to regulatory requirements rather than consideration of pure scientific needs. In this publication, we present an ongoing standardization effort to provide trustworthy machine-actionable documentation of the data lineage and specimens. We would like to invite experts from the biotechnology and biomedical fields to further contribute to the standard.</p

Towards a Common Standard for Data and Specimen Provenance in Life Sciences

The exchange of biological material and data has become an issue of major importance for research in biotechnology. At the same time, many reports indicate problems with quality, trustworthiness and reproducibility of research results, mainly due to poor documentation of data generation or collection of samples. Consequently, there is an urgent need for improved and standardized documentation of data and specimen used in research studies. In response to these issues, we are developing a provenance information standard for the biotechnology domain within the ISO Technical Committee 276 “Biotechnology”. The major objectives of the standard, now registered as ISO/WD 23494, are improved reproducibility of research results, enabling the assessment of the quality of biological samples and data, traceability and higher reliability of observations. We are convinced that the standardization project is of substantial interest to a broader audience, who we would also invite to comment and contribute to this comprehensive effort.Manuscript under consideration

Description of an aerodynamic levitation apparatus with applications in Earth sciences

<p>Abstract</p> <p>Background</p> <p>In aerodynamic levitation, solids and liquids are floated in a vertical gas stream. In combination with CO₂-laser heating, containerless melting at high temperature of oxides and silicates is possible. We apply aerodynamic levitation to bulk rocks in preparation for microchemical analyses, and for evaporation and reduction experiments.</p> <p>Results</p> <p>Liquid silicate droplets (~2 mm) were maintained stable in levitation using a nozzle with a 0.8 mm bore and an opening angle of 60°. The gas flow was ~250 ml min^-1. Rock powders were melted and homogenized for microchemcial analyses. Laser melting produced chemically homogeneous glass spheres. Only highly (e.g. H₂O) and moderately volatile components (Na, K) were partially lost. The composition of evaporated materials was determined by directly combining levitation and inductively coupled plasma mass spectrometry. It is shown that the evaporated material is composed of Na > K >> Si. Levitation of metal oxide-rich material in a mixture of H₂and Ar resulted in the exsolution of liquid metal.</p> <p>Conclusions</p> <p>Levitation melting is a rapid technique or for the preparation of bulk rock powders for major, minor and trace element analysis. With exception of moderately volatile elements Na and K, bulk rock analyses can be performed with an uncertainty of ± 5% relative. The technique has great potential for the quantitative determination of evaporated materials from silicate melts. Reduction of oxides to metal is a means for the extraction and analysis of siderophile elements from silicates and can be used to better understand the origin of chondritic metal.</p