Geographic Variation of Cirques on Iceland: Factors Influencing Cirque Morphology

Cirques are one of the most common glacial landforms in alpine settings. They also provide important paleoclimate information (e.g. Meierding 1984; Evans 2006). The purpose of this study is to fill in gaps in the climate record of Iceland by conducting a quantitative analysis of cirques in three regions in Iceland: Tröllaskagi, the East Fjords, and Vestfirðir. Iceland, located in the center of the North Atlantic Ocean, contains many small glaciers, in addition to large ice caps. The glaciers on Iceland are particularly sensitive to variations in oceanic and atmospheric circulation (Andresen et al. 2005; Geirsdóttir et al., 2009; Ólafsdóttir et al. 2010). Iceland thus provides an excellent case study to examine factors influencing glacial landforms such as cirques. (excerpt

A Novel Extraction Procedure of Contact Characteristic Parameters from Current–Voltage Curves in CdZnTe and CdTe Detectors

The estimation of the characteristic parameters of the electrical contacts in CdZnTe and CdTe detectors is related to the identification of the main transport mechanisms dominating the currents. These investigations are typically approached by modelling the current–voltage (I–V) curves with the interfacial layer–thermionic-diffusion (ITD) theory, which incorporates the thermionic emission, diffusion and interfacial layer theories into a single theory. The implementation of the ITD model in measured I–V curves is a critical procedure, requiring dedicated simplifications, several best fitting parameters and the identification of the voltage range where each transport mechanism dominates. In this work, we will present a novel method allowing through a simple procedure the estimation of some characteristic parameters of the metal–semiconductor interface in CdZnTe and CdTe detectors. The barrier height and the effects of the interfacial layer will be evaluated through the application of a new function related to the differentiation of the experimental I–V curves

A 2-year comparative open label randomized study of efficacy and safety of etanercept and infliximab in patients with ankylosing spondylitis

The signs and symptoms of ankylosing spondylitis (AS) respond inadequately to nonsteroidal antiinflammatory drugs, corticosteroids, and disease modifying antirheumatic drugs in quite a number of patients. Tumor necrosis factor inhibitors have demonstrated to be of value in reducing AS disease activity in clinical trials. The efficacy and safety of both etanercept and infliximab in patients with ankylosing spondylitis were compared in a 2-year open label randomised study. Our results are consistent with a significant more rapid clinical improvement in the infliximab treated group. Treatment with both etanercept and infliximab at the end of the study was effective, safe, and well tolerated. \ua9 2009 Springer-Verlag

Streamlined Subglacial Bedform Sensitivity to Bed Characteristics Across the Deglaciated Northern Hemisphere

Streamlined subglacial bedforms observed in deglaciated landscapes provide the opportunity to assess the sensitivity of glacier dynamics to bed characteristics across broader spatiotemporal scales than is possible for contemporary glacial systems. While many studies of streamlined subglacial bedforms rely on manual mapping and qualitative (i.e., visual) assessment, we semi-automatically identify 11,628 sedimentary and bedrock bedforms, created during and following the Last Glacial Maximum across nine geologically and topographically diverse deglaciated sites in the Northern Hemisphere. Using this large dataset of landforms and associated morphometrics, we empirically test the importance of subglacial terrain on bedform morphology and ice-flow behavior. A minimum bedform length–width ratio threshold provides a constraint on minimum morphometrics needed for streamlined bedforms to develop. Similarities in bedform metric distribution regardless of bed properties indicate that all bed types may support similar distributions of warm-based ice flow conditions. Ice flow within valleys with easily erodible beds host the most elongate bedforms yet the widest range in bedform elongation and bedform surface relief. The presence of these highly elongate bedforms suggest high ice-flow velocities occur within valley settings despite spatially heterogeneous landform-generating processes. In contrast, lithified sedimentary beds within regions not constrained by topography on the scale of 1–102 km contain bedforms with high density and packing, low change in surface relief and low elongation, indicating spatially uniform and organized interactions at the ice–bed interface and consistency in ice-flow velocity. Regardless of genesis, we find a sensitivity of bedform elongation (i.e., used to interpret ice-flow speed or persistence) to topographic conditions on the scale of 1–102 km, while bedform density is sensitive to bed lithology. The findings presented in this study provide analogues for processes of subglacial erosion and deposition, ice–bed interactions and warm-based ice flow within contemporary glacial systems

A Th1 but not a Th17 response is present in the gastrointestinal involvement of Behçet's disease

OBJECTIVES: Behçet's disease has been historically classified as a Th1 disease. The recently described IL-17/IL-23 pathway seems to play an important role in many inflammatory diseases and in the intestinal abnormalities of AS and CD. The aim of the present study was to evaluate the IL-17/IL-23 axis in parallel with Th1 and IL-27 response in the intestine of patients with BD and gastrointestinal abnormalities. METHODS: Quantitative TaqMan reverse transcriptase-polymerase chain reaction (RT-PCR) was utilised for all determinations on ileal biopsy specimens obtained from BD, AS and CD patients. The serum levels of Th1 and Th17 cytokines were evaluated by enzyme-linked immunosorbent assay. RESULTS: A Th1 but not a Th17 response is present in the gastrointestinal involvement of Behçet's disease. CONCLUSIONS: Although BD shares clinical manifestations with both CD and AS, the immunologic abnormalities seen in the intestine are quite different, indicating that other immune mechanisms should be taken into account

High performance platinum contacts on high-flux CdZnTe detectors

The need for direct X-ray detection under high photon flux with moderate or high energies (30–100 keV range) has strongly increased with the rise of the 4th Generation Synchrotron Light Sources, characterised by extremely brilliant beamlines, and of other applications such as spectral computed tomography in medicine and non-destructive tests for industry. The novel Cadmium Zinc Telluride (CZT) developed by Redlen Technologies can be considered the reference material for high-flux applications (HF-CZT). The enhanced charge transport properties of the holes allow the mitigation of the effects of radiation induced polarization phenomena, typically observed in standard CZT materials (LF-CZT) under high photon flux. However, standard LF-CZT electrical contacts led to inacceptable high dark leakage currents on HF-CZT devices. In this work, a detailed study on the characteristics of new optimized sputtered platinum electrical contacts on HF-CZT detectors is reported. The results from electrical and spectroscopic investigations, showed the best performances on HF-CZT detectors with platinum anode, coupled with both platinum or gold cathode. The morphology, structure, and composition of Pt/CZT contact have been analysed by means of Transmission Electron Microscopy (TEM) on microscopic lamellas obtained by Focused Ion Beam (FIB), highlighting the presence of CdTeO3 oxide at the metal semiconductor interface

In Solidarity

This edition of Next Page is a departure from our usual question and answer format with a featured campus reader. Instead, we asked speakers who participated in the College’s recent Student Solidarity Rally (March 1, 2017) to recommend readings that might further our understanding of the topics on which they spoke