30 research outputs found
Vortex Core Structure and Dynamics in Layered Superconductors
We investigate the equilibrium and nonequilibrium properties of the core
region of vortices in layered superconductors. We discuss the electronic
structure of singly and doubly quantized vortices for both s-wave and d-wave
pairing symmetry. We consider the intermediate clean regime, where the
vortex-core bound states are broadened into resonances with a width comparable
to or larger than the quantized energy level spacing, and calculate the
response of a vortex core to an {\em a.c.} electromagnetic field for vortices
that are pinned to a metallic defect. We concentrate on the case where the
vortex motion is nonstationary and can be treated by linear response theory.
The response of the order parameter, impurity self energy, induced fields and
currents are obtained by a self-consistent calculation of the distribution
functions and the excitation spectrum. We then obtain the dynamical
conductivity, spatially resolved in the region of the core, for external
frequencies in the range, 0.1\Delta < \hbar\omega \lsim 3\Delta. We also
calculate the dynamically induced charge distribution in the vicinity of the
core. This charge density is related to the nonequilibrium response of the
bound states and collective mode, and dominates the electromagnetic response of
the vortex core.Comment: Presented at the 2000 Workshop on ``Microscopic Structure and
Dynamics of Vortices in Unconventional Superconductors and Superfluids'',
held at the Max Planck Institute for the Physics of Complex Systems in
Dresden, Germany (28 pages with 15 figures). Alternate version with higher
resolution figures:
http://snowmass.phys.nwu.edu/~sauls/Eprints/Dresden2000.htm
The effect of short time computer work on muscle oxygenation in presence of delayed onset muscle soreness
The Pleistocene cinder cones surrounding VolcĂĄn Colima, Mexico re-visited: eruption ages and volumes, oxidation states, and sulfur content
Located at the volcanic front in the western Mexican arc, in the Colima Rift, is the active VolcĂĄn Colima, which lies on the southern end of the massive (âŒ450 km 3 ) Colima-Nevado volcanic complex. Along the margins of this andesitic volcanic complex, is a group of 11 scoria cones and associated lavas, which have been dated by the 40 Ar/ 39 Ar method. Nine scoria cones erupted âŒ1.3 km 3 of alkaline magma (basanite, leucite-basanite, minette) between 450 and 60 ka, with >99% between 240 and 60 ka. Two additional cones (both the oldest and calc-alkaline) erupted <0.003 km 3 of basalt (0.5 Ma) and <0.003 km 3 of basaltic andesite (1.2 Ma), respectively. Cone and lava volumes were estimated with the aid of digital elevation models (DEMs). The eruption rate for these scoria cones and their associated lavas over the last 1.2 Myr is âŒ1.2 km 3 /Myr, which is more than 400 times smaller than that from the andesitic Colima-Nevado edifice. In addition to these alkaline Colima cones, two other potassic basalts erupted at the volcanic front, but âŒ200 km to the ESE (near the historically active VolcĂĄn Jorullo), and were dated at 1.06 and 0.10 Ma. These potassic suites reflect the tendency in the west-central Mexican arc for magmas close to the volcanic front to be enriched in K 2 O relative to those farther from the trench.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47809/1/445_2005_Article_15.pd
What scans we will read: imaging instrumentation trends in clinical oncology
Oncological diseases account for a significant portion of the burden on public healthcare systems with associated
costs driven primarily by complex and long-lasting therapies. Through the visualization of patient-specific
morphology and functional-molecular pathways, cancerous tissue can be detected and characterized non-
invasively, so as to provide referring oncologists with essential information to support therapy management
decisions. Following the onset of stand-alone anatomical and functional imaging, we witness a push towards
integrating molecular image information through various methods, including anato-metabolic imaging (e.g., PET/
CT), advanced MRI, optical or ultrasound imaging.
This perspective paper highlights a number of key technological and methodological advances in imaging
instrumentation related to anatomical, functional, molecular medicine and hybrid imaging, that is understood as
the hardware-based combination of complementary anatomical and molecular imaging. These include novel
detector technologies for ionizing radiation used in CT and nuclear medicine imaging, and novel system
developments in MRI and optical as well as opto-acoustic imaging. We will also highlight new data processing
methods for improved non-invasive tissue characterization. Following a general introduction to the role of imaging
in oncology patient management we introduce imaging methods with well-defined clinical applications and
potential for clinical translation. For each modality, we report first on the status quo and point to perceived
technological and methodological advances in a subsequent status go section. Considering the breadth and
dynamics of these developments, this perspective ends with a critical reflection on where the authors, with the
majority of them being imaging experts with a background in physics and engineering, believe imaging methods
will be in a few years from now.
Overall, methodological and technological medical imaging advances are geared towards increased image contrast,
the derivation of reproducible quantitative parameters, an increase in volume sensitivity and a reduction in overall
examination time. To ensure full translation to the clinic, this progress in technologies and instrumentation is
complemented by progress in relevant acquisition and image-processing protocols and improved data analysis. To
this end, we should accept diagnostic images as âdataâ, and â through the wider adoption of advanced analysis,
including machine learning approaches and a âbig dataâ concept â move to the next stage of non-invasive tumor
phenotyping. The scans we will be reading in 10 years from now will likely be composed of highly diverse multi-
dimensional data from multiple sources, which mandate the use of advanced and interactive visualization and
analysis platforms powered by Artificial Intelligence (AI) for real-time data handling by cross-specialty clinical experts
with a domain knowledge that will need to go beyond that of plain imaging
Maternal smoking during pregnancy and birth defects in children: a systematic review with meta-analysis
An evaluation of metrics for assessing maternal exposure to agricultural pesticides
We evaluate the use of three different exposure metrics to estimate maternal agricultural pesticide exposure during pregnancy. Using a geographic information system-based method of pesticide exposure estimation, we combine data on crop density and specific pesticide application amounts/dates to create the three exposure metrics. For illustration purposes, we create each metric for a North Carolina cohort of pregnant women, 2003â2005, and analyze the risk of congenital anomaly development with a focus on metric comparisons. Based on the results, and the need to balance data collection efforts/computational efficiency with accuracy, the metric which estimates total chemical exposure using application dates based on crop-specific earliest planting and latest harvesting information is preferred. Benefits and drawbacks of each metric are discussed and recommendations for extending the analysis to other states are provided
Chemical differentiation, cold storage and remobilization of magma in the Earth's crust
The formation, storage and chemical differentiation of magma in the Earthâs crust is of fundamental importance in igneous geology and volcanology. Recent data are challenging the high-melt-fraction âmagma chamberâ paradigm that has underpinned models of crustal magmatism for over a century, suggesting instead that magma is normally stored in low-melt-fraction âmush reservoirsâ1,2,3,4,5,6,7,8,9. A mush reservoir comprises a porous and permeable framework of closely packed crystals with melt present in the pore space1,10. However, many common features of crustal magmatism have not yet been explained by either the âchamberâ or âmush reservoirâ concepts1,11. Here we show that reactive melt flow is a critical, but hitherto neglected, process in crustal mush reservoirs, caused by buoyant melt percolating upwards through, and reacting with, the crystals10. Reactive melt flow in mush reservoirs produces the low-crystallinity, chemically differentiated (silicic) magmas that ascend to form shallower intrusions or erupt to the surface11,12,13. These magmas can host much older crystals, stored at low and even sub-solidus temperatures, consistent with crystal chemistry data6,7,8,9. Changes in local bulk composition caused by reactive melt flow, rather than large increases in temperature, produce the rapid increase in melt fraction that remobilizes these cool- or cold-stored crystals. Reactive flow can also produce bimodality in magma compositions sourced from mid- to lower-crustal reservoirs14,15. Trace-element profiles generated by reactive flow are similar to those observed in a well studied reservoir now exposed at the surface16. We propose that magma storage and differentiation primarily occurs by reactive melt flow in long-lived mush reservoirs, rather than by the commonly invoked process of fractional crystallization in magma chambers[14]