3,056 research outputs found
Interaction effects and charge quantization in single-particle quantum dot emitters
We discuss a theoretical model of an on-demand single-particle emitter that
employs a quantum dot, attached to an integer or fractional quantum Hall edge
state. Via an exact mapping of the model onto the spin-boson problem we show
that Coulomb interactions between the dot and the chiral quantum Hall edge
state, unavoidable in this setting, lead to a destruction of precise charge
quantization in the emitted wave-packet. Our findings cast doubts on the
viability of this set-up as a single-particle source of quantized charge
pulses. We further show how to use a spin-boson master equation approach to
explicitly calculate the current pulse shape in this set-up.Comment: 5+5 pages, 3 figures, fixed typos, update Supplement Material and
update figure
Feasibility and Design Studies: Camplain Valley Sanitary Landfill
Guidebook for field trips in Vermont: 64th annual meeting October 13, 14, 15, 1972 Burlington, Vermont: Trip EG-
Potential Role of Protease Nexin-2/Amyloid Î’-Protein Precursor as a Cerebral Anticoagulant a
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74723/1/j.1749-6632.1992.tb27493.x.pd
Mammalian Cell Cytotoxicity Analysis of Soybean Rust Fungicides
The identification of soybean rust, caused by Phakopsora
pachyrhizi H. Sydow & Sydow, in the southern United
States in November 2004 (Schneider et al. 2005 ), in the
Midwest in 2006 (Hartman et al. 2007 ), and elsewhere has
increased the concerns of the impact of the pathogen on US
soybean production (Miles et al. 2007 ). The rapid spread of
P. pachyrhizi and its potential to cause severe yield losses
makes this among the most destructive foliar diseases of
soybean. Yield losses of 20%–60% were reported in Asia,
with losses of 80% reported from experimental plots in
Taiwan (Hartman et al. 1991 ). Soybean rust could have a
major impact on both total soybean production and production
costs in the US
Mammalian Cell Cytotoxicity Analysis of Soybean Rust Fungicides
The identification of soybean rust, caused by Phakopsora
pachyrhizi H. Sydow & Sydow, in the southern United
States in November 2004 (Schneider et al. 2005 ), in the
Midwest in 2006 (Hartman et al. 2007 ), and elsewhere has
increased the concerns of the impact of the pathogen on US
soybean production (Miles et al. 2007 ). The rapid spread of
P. pachyrhizi and its potential to cause severe yield losses
makes this among the most destructive foliar diseases of
soybean. Yield losses of 20%–60% were reported in Asia,
with losses of 80% reported from experimental plots in
Taiwan (Hartman et al. 1991 ). Soybean rust could have a
major impact on both total soybean production and production
costs in the US
Quality of Emergency Care on the Night Shift
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72839/1/j.aem.2005.09.005.pd
A γ-secretase inhibitor, but not a γ-secretase modulator, induced defects in BDNF axonal trafficking and signaling: evidence for a role for APP.
Clues to Alzheimer disease (AD) pathogenesis come from a variety of different sources including studies of clinical and neuropathological features, biomarkers, genomics and animal and cellular models. An important role for amyloid precursor protein (APP) and its processing has emerged and considerable interest has been directed at the hypothesis that Aβ peptides induce changes central to pathogenesis. Accordingly, molecules that reduce the levels of Aβ peptides have been discovered such as γ-secretase inhibitors (GSIs) and modulators (GSMs). GSIs and GSMs reduce Aβ levels through very different mechanisms. However, GSIs, but not GSMs, markedly increase the levels of APP CTFs that are increasingly viewed as disrupting neuronal function. Here, we evaluated the effects of GSIs and GSMs on a number of neuronal phenotypes possibly relevant to their use in treatment of AD. We report that GSI disrupted retrograde axonal trafficking of brain-derived neurotrophic factor (BDNF), suppressed BDNF-induced downstream signaling pathways and induced changes in the distribution within neuronal processes of mitochondria and synaptic vesicles. In contrast, treatment with a novel class of GSMs had no significant effect on these measures. Since knockdown of APP by specific siRNA prevented GSI-induced changes in BDNF axonal trafficking and signaling, we concluded that GSI effects on APP processing were responsible, at least in part, for BDNF trafficking and signaling deficits. Our findings argue that with respect to anti-amyloid treatments, even an APP-specific GSI may have deleterious effects and GSMs may serve as a better alternative
Survival and Selection of Migrating Salmon from Capture-Recapture Models with Individual Traits
Capture–recapture studies are powerful tools for studying animal population dynamics, providing information on population abundance, survival rates, population growth rates, and selection for phenotypic traits. In these studies, the probability of observing a tagged individual reflects both the probability of the individual surviving to the time of recapture and the probability of recapturing an animal, given that it is alive. If both of these probabilities are related to the same phenotypic trait, it can be difficult to distinguish effects on survival probabilities from effects on recapture probabilities. However, when animals are individually tagged and have multiple opportunities for recapture, we can properly partition observed trait-related variability into survival and recapture components. We present an overview of capture–recapture models that incorporate individual variability and develop methods to incorporate results from these models into estimates of population survival and selection for phenotypic traits. We conducted a series of simulations to understand the performance of these estimators and to assess the consequences of ignoring individual variability when it exists. In addition, we analyzed a large data set of .153 000 juvenile chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss) of known length that were PIT-tagged during their seaward migration. Both our simulations and the case study indicated that the ability to precisely estimate selection for phenotypic traits was greatly compromised when differential recapture probabilities were ignored. Estimates of population survival, however, were far more robust. In the chinook salmon and steelhead study, we consistently found that smaller fish had a greater probability of recapture. We also uncovered length-related survival relationships in over half of the release group/river segment combinations that we observed, but we found both positive and negative relationships between length and survival probability. These results have important implications for the management of salmonid populations
Behavioral Responses of Pacific Lamprey to Alarm Cues
Pacific lamprey (Entosphenus tridentatus), an anadromous ectoparasite, faces several challenges during adult migration to spawning grounds. Developingmethods to address these challenges is critical to the success of ongoing conservation efforts. The challenges are diverse, and include anthropogenic alterations to the ecosystem resulting in loss of habitat, impassable barriers such as dams, climate change impacts, and altered predator fields. We conducted a behavioral study to understand how adult migrating Pacific lamprey respond to potential alarm cues: White Sturgeon (Acipenser transmontanus), human saliva, decayed Pacific lamprey, and river otter (Lontra canadensis). Research has shown that some species of lamprey can be guided to a location using odors and similar cues may be useful as a management tool for Pacific lamprey. Experiments were conducted over 2 nights and measured the number of entries (count) and duration of time spent (occupancy) by adult lamprey in each arm of a two-choice maze. During the first night, no odor was added to test for selection bias between arms. During the second night odor was added to one arm of the maze. Contrary to expectations, lamprey were significantly attracted to the river otter odor in both count and occupancy. No significant differences were found in the response of lamprey to the other three odors. Results from this study indicate that Pacific lamprey do respond to some odors; however, additional tests are necessary to better identify the types of odors and concentrations that elicit a repeatable response
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