Improved retrieval of land ice topography from CryoSat-2 data and its impact for volume-change estimation of the Greenland Ice Sheet

A new methodology for retrieval of glacier and ice sheet elevations and elevation changes from CryoSat-2 data is presented. Surface elevations and elevation changes determined using this approach show significant improvements over ESA's publicly available CryoSat-2 elevation product (L2 Baseline-B). The results are compared to near-coincident airborne laser altimetry from NASA's Operation IceBridge and seasonal height amplitudes from the Ice, Cloud, and Elevation Satellite (ICESat). Applying this methodology to CryoSat-2 data collected in interferometric synthetic aperture mode (SIN) over the high-relief regions of the Greenland Ice Sheet we find an improvement in the root-mean-square error (RMSE) of 27 and 40 % compared to ESA's L2 product in the derived elevation and elevation changes, respectively. In the interior part of the ice sheet, where CryoSat-2 operates in low-resolution mode (LRM), we find an improvement in the RMSE of 68 and 55 % in the derived elevation and elevation changes, respectively. There is also an 86 % improvement in the magnitude of the seasonal amplitudes when compared to amplitudes derived from ICESat data. These results indicate that the new methodology provides improved tracking of the snow/ice surface with lower sensitivity to changes in near-surface dielectric properties. To demonstrate the utility of the new processing methodology we produce elevations, elevation changes, and total volume changes from CryoSat-2 data for the Greenland Ice Sheet during the period January 2011 to January 2015. We find that the Greenland Ice Sheet decreased in volume at a rate of 289 ± 20 km3a−1, with high interannual variability and spatial heterogeneity in rates of loss. This rate is 65 km3a−1 more negative than rates determined from ESA's L2 product, highlighting the importance of CryoSat-2 processing methodologies.</p

Mass changes in Arctic ice caps and glaciers: implications of regionalizing elevation changes

The mass balance of glaciers and ice caps is sensitive to changing climate conditions. The mass changes derived in this study are determined from elevation changes derived measured by the Ice, Cloud, and land Elevation Satellite (ICESat) for the time period 2003–2009. Four methods, based on interpolation and extrapolation, are used to regionalize these elevation changes to areas without satellite coverage. A constant density assumption is then applied to estimate the mass change by integrating over the entire glaciated region. <br><br> The main purpose of this study is to investigate the sensitivity of the regional mass balance of Arctic ice caps and glaciers to different regionalization schemes. The sensitivity analysis is based on studying the spread of mass changes and their associated errors, and the suitability of the different regionalization techniques is assessed through cross-validation. <br><br> The cross-validation results shows comparable accuracies for all regionalization methods, but the inferred mass change in individual regions, such as Svalbard and Iceland, can vary up to 4 Gt a⁻¹, which exceeds the estimated errors by roughly 50% for these regions. This study further finds that this spread in mass balance is connected to the magnitude of the elevation change variability. This indicates that care should be taken when choosing a regionalization method, especially for areas which exhibit large variability in elevation change

Exome sequencing of contralateral breast cancer identifies metastatic disease

Women with contralateral breast cancer (CBC) have significantly worse prognosis compared to women with unilateral cancer. A possible explanation of the poor prognosis of patients with CBC is that in a subset of patients, the second cancer is not a new primary tumor but a metastasis of the first cancer that has potentially obtained aggressive characteristics through selection of treatment. Exome and whole-genome sequencing of solid tumors has previously been used to investigate the clonal relationship between primary tumors and metastases in several diseases. In order to assess the relationship between the first and the second cancer, we performed exome sequencing to identify somatic mutations in both first and second cancers, and compared paired normal tissue of 25 patients with metachronous CBC. For three patients, we identified shared somatic mutations indicating a common clonal origin thereby demonstrating that the second tumor is a metastasis of the first cancer, rather than a new primary cancer. Accordingly, these patients all developed distant metastasis within 3 years of the second diagnosis, compared with 7 out of 22 patients with non-shared somatic profiles. Genomic profiling of both tumors help the clinicians distinguish between true CBCs and subsequent metastasesVetenskapsrådetForteAccepte

Digital Platform Establishment: Navigating Competing Concerns in Emerging Ecosystems

Digital Platforms impose organizing logics on ecosystems. Dependent on their configuration, they enable certain practices, relationships, and value distribution among actors while preventing alternatives. Incumbent platforms often have a strong power to implement contested configurations since they control access to attractive user groups/markets. However, emerging platforms have a small degree of bargaining power in relation to key actors since they have not yet achieved such a position. Although numerous studies detail governance strategies for incumbent platform ecosystems, research on how platform providers navigate competing concerns in emerging platform ecosystems remain rare. We report on a study of the establishment and continuous dynamics of a digital platform used for service innovation. We inductively identify a pattern of the dynamics in this navigation process, locate four salient tensions driving these dynamics, and provide insights on how the platform provider navigated them

Designing Synchronised Multi-user Augmented Reality Experiences

With the recent advances in AR technology, there is now the possibility to create multi-user experiences that are completely synchronised between users. This thesis defines and explores the domain of Synchronised Multi-user Augmented Reality Experience (SMARE). Existing literature and applications within the area are examined and three different prototypes are created and evaluated in order to define a set of guidelines for aspects to consider when designing SMAREs. Through a process of iteratively developing prototypes and guidelines, a set of guidelines consisting of five categories with a total of 18 guidelines is defined. The results of the prototyping are AR-Showcase, AR-Racing and LumbAR which are three rather different mobile AR applications that attempt to explore different parts of the design space. The final set of guidelines is not exhaustive and rather than acting as strict rules, the guidelines should be seen as areas worth considering when designing SMAREs, and also interesting areas for further research on the subject. Even though the guidelines were developed from mobile AR applications, the goal was to make them as general as possible so that they could be used for other platforms and technologies as well

BIOSAR 2010 - A SAR campaign in support to the BIOMASS mission

The ESA funded campaign BioSAR 2010 was carried out at the forestry test site Remningstorp in southern Sweden, in support to the BIOMASS satellite mission under study. Fully polarimetric SAR data were successfully acquired at L- and P-band using ONERA's multi-frequency system SETHI. In addition with other data types gathered, e.g. LiDAR and in-situ measurements, the compiled data set will be used for analyses and comparisons with biomass estimation results obtained at the same test site in the campaign BioSAR 2007, in which DLR's E-SAR made the SAR imaging. Detection of forest changes, robustness of biomass retrieval algorithms and long-term P-band coherence will be in focus as well as cross-validations between the two SAR sensors

Dynamic MAIT cell response with progressively enhanced innateness during acute HIV-1 infection.

Mucosa-associated invariant T (MAIT) cell loss in chronic HIV-1 infection is a significant insult to antimicrobial immune defenses. Here we investigate the response of MAIT cells during acute HIV-1 infection utilizing the RV217 cohort with paired longitudinal pre- and post-infection samples. MAIT cells are activated and expand in blood and mucosa coincident with peak HIV-1 viremia, in a manner associated with emerging microbial translocation. This is followed by a phase with elevated function as viral replication is controlled to a set-point level, and later by their functional decline at the onset of chronic infection. Interestingly, enhanced innate-like pathways and characteristics develop progressively in MAIT cells during infection, in parallel with TCR repertoire alterations. These findings delineate the dynamic MAIT cell response to acute HIV-1 infection, and show how the MAIT compartment initially responds and expands with enhanced function, followed by progressive reprogramming away from TCR-dependent antibacterial responses towards innate-like functionality

Educating Reflective Practitioners: The Design of an IT Management Masters Program

The IT Management Group at Umeå University, Sweden, has developed a master program in IT management with emphasison incorporating practice in the learning process. The basic premise lies in the use of reflection-in-action as an approach topresenting students with practical problems throughout the program. We discuss the ways in which practice is at the heart ofthe program, both as a tool for exemplifying codified knowledge such as technical skills and methods but also as arenas forsituated knowledge creation and transfer where reflection and action are intertwined. The paper ends with a discussion of theprogram design, challenges in implementing the reflective practice approach and competencies the students need in theirfuture professional roles

Cycles of Innovation and Alignment in Digital Transformation: Investigating the Dynamics of Resource Recombination in a Construction Firm

The generative nature of digital technology implies that during digital transformation (DT), organizations traverse multiple cycles of innovation and resource alignment. Still, extant research mainly chronicles DT as linear and contained phenomenon occurring in response to a dramatic environmental change event. How new resources align with previous ones into novel combinations, the work that supports continuous organizational capability building, and the temporal relationships between cycles of change in DT has received scant attention. Drawing on dynamic capability theory, we analyze innovation and resource alignment cycles driving DT at Lundqvist Trävaru AB, a small Swedish construction firm. Our study has at least two contributions. First, the analysis reveals three types of dynamic capabilities that shape resource generation and alignment in DT. Second, we provide a process model outlining the innovation and alignment cycles that fuel DT as they scale in the focal firm

Digital Options Theory for IT Capability Investment

While research has shown that investments in IT capability may translate into improved firm performance, how and why they do is still a source of debate. Drawing on financial options thinking, recent research suggests that managers can support appropriate investment decisions by examining digital options. However, current research has not effectively translated the financial options construct into the IT domain, which makes it difficult to rigorously examine digital options. To address this void, we revisit general options theory and review current notions of digital options. To support understanding, we extend current theorizing by offering a rigorous conceptual foundation that defines the digital option lifecycle and relationships to neighboring constructs. To support practice, we present principles for examining digital options for a specific business process. To illustrate the detailed workings of the theory, we examine a production planning process in the dairy industry to arrive at a set of desirable and feasible IT capability investments. Our proposed theory supports managerial practice by offering a rigorous and actionable foundation for digital options thinking. It also sets an agenda for academic research by articulating theory-based constructs and principles that are subject to further empirical and theoretical investigation