686 research outputs found
Temporal response of mountain drainage basins in Taiwan to earthquake and typhoon perturbation.
In tectonically-active mountain belts, earthquake-triggered landslides deliver large amounts of sediment to rivers. In previous work, we have quantified the geomorphic impact of the 1999 Mw 7.6 Chi-Chi earthquake in Taiwan, which triggered >20,000 landslides and elevated suspended sediment loads in rivers by up to a factor of four. At the time, many coseismic landslides remained confined to hillslopes and, on the basis of four years of hydrometric data, we predicted that downslope transport of sediment would continue to occur during later storms. During the seven years since the Chi- Chi earthquake, several major typhoons storms have hit Taiwan (e.g., Typhoons Bilis, Toraji, Nari, Mindulle, Aere) and the Water Resources Agency of Taiwan has contin- ued to monitor water discharge and suspended sediment concentration. Here we use these new data to refine the spatial and temporal pattern of the decaying geomorphic response to the Chi-Chi earthquake in the face of several large typhoons. Our results indicate that the broad pattern of exponential decay in sediment concentration for a given river discharge (prevalent in winter seasons without typhoons) is punctuated by markedly elevated periods associated with typhoon storms. However, our analyses show that the change in unit sediment concentration (i.e., suspended sediment concen- tration for a unit water discharge) associated with each storm depends more strongly on the length of time elapsed since the earthquake than it does on the magnitude of the storm itself
Plasticity changes in forebrain activity and functional connectivity during neuropathic pain development in rats with sciatic spared nerve injury
Abstract
Neuropathic pain is a major worldwide health problem. Although central sensitization has been reported in well-established neuropathic conditions, information on the acute brain activation patterns in response to peripheral nerve injury is lacking. This study first mapped the brain activity in rats immediately following spared nerve injury (SNI) of the sciatic nerve. Using blood-oxygenation-level-dependent functional magnetic resonance imaging (BOLD-fMRI), we observed sustained activation in the bilateral insular cortices (ICs), primary somatosensory cortex (S1), and cingulate cortex. Second, this study sought to link this sustained activation pattern with brain sensitization. Using manganese-enhanced magnetic resonance imaging (MEMRI), we observed enhanced activity in the ipsilateral anterior IC (AIC) in free-moving SNI rats on Days 1 and 8 post-SNI. Furthermore, enhanced functional connectivity between the ipsilateral AIC, bilateral rostral AIC, and S1 was observed on Day 8 post-SNI. Chronic electrophysiological recording experiments were conducted to confirm the tonic neuronal activation in selected brain regions. Our data provide evidence of tonic activation-dependent brain sensitization during neuropathic pain development and offer evidence that the plasticity changes in the IC and S1 may contribute to neuropathic pain development
Selective interlayer ferromagnetic coupling between the Cu spins in YBa Cu O grown on top of La Ca MnO
Studies to date on ferromagnet/d-wave superconductor heterostructures focus
mainly on the effects at or near the interfaces while the response of bulk
properties to heterostructuring is overlooked. Here we use resonant soft x-ray
scattering spectroscopy to reveal a novel c-axis ferromagnetic coupling between
the in-plane Cu spins in YBa Cu O (YBCO) superconductor when it
is grown on top of ferromagnetic La Ca MnO (LCMO) manganite
layer. This coupling, present in both normal and superconducting states of
YBCO, is sensitive to the interfacial termination such that it is only observed
in bilayers with MnO_2but not with La Ca interfacial
termination. Such contrasting behaviors, we propose, are due to distinct
energetic of CuO chain and CuO plane at the La Ca and
MnO terminated interfaces respectively, therefore influencing the transfer
of spin-polarized electrons from manganite to cuprate differently. Our findings
suggest that the superconducting/ferromagnetic bilayers with proper interfacial
engineering can be good candidates for searching the theorized
Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) state in cuprates and studying the
competing quantum orders in highly correlated electron systems.Comment: Please note the change of the title. Text might be slightly different
from the published versio
First-in-Human Study of MANP: A Novel ANP (Atrial Natriuretic Peptide) Analog in Human Hypertension
[Figure: see text]
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