4,593 research outputs found
A Note on Shareholder Oversight and the Regulatory Environment: The Japanese Banking Experience
During a period where Japanese banks operated under a less restrictive regulatory environment, 1986-88, we find positive relationships between bank risk and ownership concentration. This empirical evidence reveals shareholder activism by the largest shareholders. During the periods immediately before and immediately after this particular subperiod, which are characterized by stricter regulatory environments, we do not observe evidence of shareholder activism. Taken together, these results are consistent with the argument that restrictive regulation and shareholder oversight are substitutes for one another. Time-series results and bank performance results yield consistent evidence.Large shareholders, Japanese banks, bank risk, shareholder oversight
Essential BIM input data study for housing refurbishment:Homeowners' preferences in the UK
Construction customers are persistently seeking to achieve sustainability and maximize value as sustainability has become a major consideration in the construction industry. In particular, it is essential to refurbish a whole house to achieve the sustainability agenda of 80% CO2 reduction by 2050 as the housing sector accounts for 28% of the total UK CO2 emission. However, whole house refurbishment seems to be challenging due to the highly fragmented nature of construction practice, which makes the integration of diverse information throughout the project lifecycle difficult. Consequently, Building Information Modeling (BIM) is becoming increasingly difficult to ignore in order to manage construction projects in a collaborative manner, although the current uptake of the housing sector is low at 25%. This research aims to investigate homeowners' decision making factors for housing refurbishment projects and to provide a valuable dataset as an essential input to BIM for such projects. One-hundred and twelve homeowners and 39 construction professionals involved in UK housing refurbishment were surveyed. It was revealed that homeowners value initial cost more while construction professionals value thermal performance. The results supported that homeowners and professionals both considered the first priority to be roof refurbishment. This research revealed that BIM requires a proper BIM dataset and objects for housing refurbishment
Spectrometric test of a linear array sensor
A spectroradiometer which measures spectral reflectivities and irradiance in discrete spectral channels was tested to determine the accuracy of its wavelength calibration. This sensor is a primary tool in the remote sensing investigations conducted on biomass at NASA's Goddard Space Flight Center. Measurements have been collected on crop and forest plants both in the laboratory and field with this radiometer to develop crop identification and plant stress remote sensing techniques. Wavelength calibration is essential for use in referencing the study measurements with those of other investigations and satellite remote sensor data sets. This calibration determines a wavelength vs channel address conversion which was found to have an RMS deviation of approximately half a channel, or 1.5 nm in the range from 360 to 1050 nm. A comparison of these results with those of another test showed an average difference of approximately 4 nm, sufficiently accurate for most investigative work
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The tarantula toxin GxTx detains K+ channel gating charges in their resting conformation.
Allosteric ligands modulate protein activity by altering the energy landscape of conformational space in ligand-protein complexes. Here we investigate how ligand binding to a K+ channel's voltage sensor allosterically modulates opening of its K+-conductive pore. The tarantula venom peptide guangxitoxin-1E (GxTx) binds to the voltage sensors of the rat voltage-gated K+ (Kv) channel Kv2.1 and acts as a partial inverse agonist. When bound to GxTx, Kv2.1 activates more slowly, deactivates more rapidly, and requires more positive voltage to reach the same K+-conductance as the unbound channel. Further, activation kinetics are more sigmoidal, indicating that multiple conformational changes coupled to opening are modulated. Single-channel current amplitudes reveal that each channel opens to full conductance when GxTx is bound. Inhibition of Kv2.1 channels by GxTx results from decreased open probability due to increased occurrence of long-lived closed states; the time constant of the final pore opening step itself is not impacted by GxTx. When intracellular potential is less than 0 mV, GxTx traps the gating charges on Kv2.1's voltage sensors in their most intracellular position. Gating charges translocate at positive voltages, however, indicating that GxTx stabilizes the most intracellular conformation of the voltage sensors (their resting conformation). Kinetic modeling suggests a modulatory mechanism: GxTx reduces the probability of voltage sensors activating, giving the pore opening step less frequent opportunities to occur. This mechanism results in K+-conductance activation kinetics that are voltage-dependent, even if pore opening (the rate-limiting step) has no inherent voltage dependence. We conclude that GxTx stabilizes voltage sensors in a resting conformation, and inhibits K+ currents by limiting opportunities for the channel pore to open, but has little, if any, direct effect on the microscopic kinetics of pore opening. The impact of GxTx on channel gating suggests that Kv2.1's pore opening step does not involve movement of its voltage sensors
A frictionless microswimmer
We investigate the self-locomotion of an elongated microswimmer by virtue of
the unidirectional tangential surface treadmilling. We show that the propulsion
could be almost frictionless, as the microswimmer is propelled forward with the
speed of the backward surface motion, i.e. it moves throughout an almost
quiescent fluid. We investigate this swimming technique using the special
spheroidal coordinates and also find an explicit closed-form optimal solution
for a two-dimensional treadmiler via complex-variable techniques.Comment: 6 pages, 4 figure
Biophysics at the coffee shop: lessons learned working with George Oster
Over the past 50 years, the use of mathematical models, derived from physical
reasoning, to describe molecular and cellular systems has evolved from an art
of the few to a cornerstone of biological inquiry. George Oster stood out as a
pioneer of this paradigm shift from descriptive to quantitative biology not
only through his numerous research accomplishments, but also through the many
students and postdocs he mentored over his long career. Those of us fortunate
enough to have worked with George agree that his sharp intellect, physical
intuition and passion for scientific inquiry not only inspired us as scientists
but also greatly influenced the way we conduct research. We would like to share
a few important lessons we learned from George in honor of his memory and with
the hope that they may inspire future generations of scientists.Comment: 22 pages, 3 figures, accepted in Molecular Biology of the Cel
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