20,412 research outputs found
The Production of a Monoclonal Antibody That Blocks the Action of a Neurite Outgrowth-promoting Factor
How growing axons are guided to their targets has been the subject of much speculation. A popular hypothesis is that there are macromolecules in the extracellular matrix (ECM) or on the surfaces of other cells that form pathways for axon guidance. Such molecular signals could act via a number of different mechanisms. One way of directing neurite growth is by providing a very adhesive surface for growth cone attachment (Letourneau 1975). There are, however, more elaborate ways in which such molecules could function. For instance, the extracellular signals could be recognized by surface receptors on the axons, or be internalized where they could influence the rate or direction of neurite growth. Nerve growth factor (NGF), for instance, can act as a chemoattractive agent by binding to growing neurites (Gundersen and Barrett 1980; Claude et al. 1982). A variety of cells, both non-neuronal and neuronal, might synthesize guidance molecules. Clearly, all target cells are candidates for
synthesizing these factors, as was demonstrated for
NGF (Ebendal et al. 1980; Korsching and Thoenen
1983). If neurons were to secrete guidance or adhesion
molecules, and deposit them in an ECM along their axonal
length, then these factors would be ideally localized
for directing regrowth of neurites after axotomy.
In addition, there is evidence that neuronal surfaces
contain molecules that are adhesive for other neurites
or growth cones (Rutishauser et al. 1978; Bentley and
Keshishian 1982; Tagbert et al. 1982)
Development of a global model for atmospheric backscatter at CO2 wavelengths
The variation of the aerosol backscattering at 10.6 micrometers within the free troposphere was investigated and a model to describe this variation was developed. The analysis combines theoretical modeling with the results contained within three independent data sets. The data sets used were obtained by the SAGE I/SAM II satellite experiments, the GAMETAG flight series, and by direct backscatter measurements. The theoretical work includes use of a bimodal, two component aerosol model, and the study of the microphysical and associated optical changes occurring within an aerosol plume. A consistent picture is obtained that describes the variation of the aerosol backscattering function in the free troposphere with altitude, latitude, and season
Development of global model for atmospheric backscatter at CO2 wavelengths
The improvement of an understanding of the variation of the aerosol backscattering at 10.6 micron within the free troposphere and the development model to describe this was undertaken. The analysis combines theoretical modeling with the results contained within three independent data sets. The data sets are obtained by the SAGE I/SAM II satellite experiments, the GAMETAG flight series and by direct backscatter measurements. The theoretical work includes use of a bimodal, two component aerosol model, and the study of the microphysical and associated optical changes occurring within an aerosol plume. A consistent picture is obtained, which describes the variation of the aerosol backscattering function in the free troposphere with altitude, latitude, and season. Most data are available and greatest consistency is found inside the Northern Hemisphere
Development and evaluation of an impedance cardiographic system to measure cardiac output and other cardiac parameters Final progress report 1 Jul. 1969 - 31 Dec. 1970
Performance of impedance cardiograph for measuring heart rate and body fluid
Generation of Neuronal Diversity: Analogies and Homologies with Hematopoiesis
The immense variety of neuronal phenotypes in the vertebrate nervous system is apparent in considering just the process of chemical transmission. There are approximately 12 known classical neurotransmitters and more than 30 neuropeptides thus far identified, and individual neurons simultaneously synthesize, store, and secrete one or more classical transmitters in addition to three or more neuropeptides. The transmitters and peptides are expressed in an exceedingly large number of different combinations in different parts of the nervous system. Although there are useful generalizations as to the frequency of certain transmitter-peptide combinations, there are innumerable exceptions to these rules. How the particular combinations produced in each neuron are specified during development is a challenging question. The magnitude of this problem becomes clear if one calculates the number of possible combinations if a neuron is to produce 2 transmitters out of a possible 12 and 3 peptides out of a possible 30. There are 267,960 different potential phenotypes in this example
Development and Evaluation of an Impedance Cardiographic System to Measure Cardiac Output and Other Cardiac Parameters, 1 July 1968 - 30 June 1969
Impedance cardiographic system to measure cardiac output and cardiovascular function
Search for Lorentz Invariance and CPT Violation with the MINOS Far Detector
We searched for a sidereal modulation in the MINOS far detector neutrino rate. Such a signal would be
a consequence of Lorentz and CPT violation as described by the standard-model extension framework. It
also would be the first detection of a perturbative effect to conventional neutrino mass oscillations. We
found no evidence for this sidereal signature, and the upper limits placed on the magnitudes of the Lorentz
and CPT violating coefficients describing the theory are an improvement by factors of 20–510 over the
current best limits found by using the MINOS near detector
Improved Measurement of Muon Antineutrino Disappearance in MINOS
We report an improved measurement of ν̅_μ disappearance over a distance of 735 km using the MINOS detectors and the Fermilab Main Injector neutrino beam in a ν̅_μ-enhanced configuration. From a total exposure of 2.95×10^20 protons on target, of which 42% have not been previously analyzed, we make the most precise measurement of Δm̅^2=[2.62_(-0.28)^(+0.31)(stat)±0.09(syst)]×10^(-3)  eV^2 and constrain the ν_μ mixing angle sin^(2)(2θ̅)>0.75 (90% C.L.). These values are in agreement with Δm^2 and sin^(2)(2θ) measured for νμ, removing the tension reported in [ P. Adamson et al. Phys. Rev. Lett. 107 021801 (2011)]
The Interrelation between Audit Quality and Managerial Reporting Choices and Its Effects on Financial Reporting Quality
Two distinct lines of research have been dedicated to empirically testing how financial reporting quality (measured as the earnings response coefficient or ERC) is associated with management's choice of reporting bias and with audit quality. However, researchers have yet to consider how ERCs are affected by either the auditor's reaction to changes in the manager's reporting bias or the manager's reaction to changes in audit quality. Our study provides theoretical guidance on these interrelations and how changes in the manager's or the auditor's incentives affect both reporting bias and audit quality. Specifically, when the manager's cost (benefit) of reporting bias increases (decreases), we find that expected bias decreases, inducing the auditor to react by reducing audit quality. Because we also find that the association between expected audit quality and ERCs is always positive, changes in managerial incentives for biased reporting lead to a positive association between ERCs and expected reporting bias. When the cost of auditing decreases or the cost of auditor liability increases, we find that expected audit quality increases, inducing the manager to react by decreasing reporting bias. In this case, changes in the costs of audit quality lead to a negative association between ERCs and expected reporting bias. Finally, we demonstrate the impact of our theoretical findings by focusing on the empirical observations documented in the extant literature on managerial ownership and accounting expertise on the audit committee. In light of our framework, we provide new interpretations of these empirical observations and new predictions for future research
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