441 research outputs found

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

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    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

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    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<sup>−1</sup>, 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

    Treatment with Anti-HER2 Chimeric Antigen Receptor Tumor-Infiltrating Lymphocytes (CAR-TILs) Is Safe and Associated with Antitumor Efficacy in Mice and Companion Dogs

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    Patients with metastatic melanoma have a historically poor prognosis, but recent advances in treatment options, including targeted therapy and immunotherapy, have drastically improved the outcomes for some of these patients. However, not all patients respond to available treatments, and around 50% of patients with metastatic cutaneous melanoma and almost all patients with metastases of uveal melanoma die of their disease. Thus, there is a need for novel treatment strategies for patients with melanoma that do not benefit from the available therapies. Chimeric antigen receptor-expressing T (CAR-T) cells are largely unexplored in melanoma. Traditionally, CAR-T cells have been produced by transducing blood-derived T cells with a virus expressing CAR. However, tumor-infiltrating lymphocytes (TILs) can also be engineered to express CAR, and such CAR-TILs could be dual-targeting. To this end, tumor samples and autologous TILs from metastasized human uveal and cutaneous melanoma were expanded in vitro and transduced with a lentiviral vector encoding an anti-HER2 CAR construct. When infused into patient-derived xenograft (PDX) mouse models carrying autologous tumors, CAR-TILs were able to eradicate melanoma, even in the absence of antigen presentation by HLA. To advance this concept to the clinic and assess its safety in an immune-competent and human-patient-like setting, we treated four companion dogs with autologous anti-HER2 CAR-TILs. We found that these cells were tolerable and showed signs of anti-tumor activity. Taken together, CAR-TIL therapy is a promising avenue for broadening the tumor-targeting capacity of TILs in patients with checkpoint immunotherapy-resistant melanoma

    Прикладна механіка і основи конструювання: навчально-методичний посібник

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    Розроблено відповідно до навчальної програми і призначено для виконання розрахунково-графічної роботи з дисципліни «Прикладна механіка і основи конструювання» студентам напряму підготовки 6.050202 «Автоматизація та компютерно-ігрегровані технології» денної та заочної форм навчання. Посібник рекомендовано також для самостійної роботи студентів, оскільки він вміщує короткі теоретичні викладки основного матеріалу дисципліни «Прикладна механіка і основи конструювання», умови завдань, приклади їх розв’язування, необхідні довідкові дані

    Custom, resistance and politics : local experiences of improvement in early modern England

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    This thesis discusses popular participation in politics in early modern England and focqses on four inter-related themes that are central to our understanding of this subject: custom, improvement, public policy and resistance. These themes have been prominent in the recent historiographies either of public policy or of social relations in early modern England, but there has, as yet, been little attempt to relate these historiographies, and still less to study their central themes in the context of local experience. Full-scale case-studies of two series of enclosure riots that occurred during the 1640s, one in Duffield Frith (Derbyshire) and the other in Whittlesey (Cambridgeshire), examine closely both the micro-politics of the defence of custom within these communities and the implications ofrecent redefinitions of 'politics'. Research was undertaken not only in national but also in local archives. Indeed the two series ofriots were specifically selected because it was evident that sufficient local records had survived to permit reconstructions of the two economies upon which 'improvement' was imposed and of social relationships within the two communities. It has, moreover, been possible to recover details of various revenueraising policies implemented by the early Stuart kings or their 'ministers that have previously been studied only briefly. The discussion synthesises the contributions ofthose historians who have done 'so much in recent years to reinvigorate the historiography ofrural social and political relations, and argues that the complex rehitionships between crown policy, local resistance and popular politics can best be reconstructed through the exploration of the micro-politics of custom. It also argues that participation in politics by ordinary people went much further than many recent historians have believed. Such participation was cohflned neither to local 'horizontal' politics, nor to 'vertical' politics in terms of petitioning parliament or waging law in the central courts, but even encompassed actively choosing to vote in parliamentary elections.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
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