5,668 research outputs found
Technology and Urban Management. Semiannual Report, October 1, 1967 through March 31, 1968
The projects under Technology and Urban Management (TAUM) have continued during the last few months with considerable success. The individual studies conducted in the City of Oakland and the progress made are described in this report
The generalized Lindemann melting coefficient
Lindemann developed the melting temperature theory over 100 years ago, known
as the Lindemann criterion. Its main assumption is that melting occurs when the
root-mean-square vibration amplitude of ions and atoms in crystals exceeds a
critical fraction, h of the inter-atomic spacing in crystals. The Lindemann
coefficient h is undefined and scientific papers report different h values for
different elements. Here we present previously unobserved data trends pointing
to the fact that the Lindemann coefficient could be linked to the periodic
groups of the periodic table, having an exact value for each element belonging
to a given periodic group. We report 12 distinctive Lindemann coefficient
values corresponding to 12 groups of the periodic table containing solid
elements with identifiable melting temperature. Using these vales, the
recalculation of the melting temperatures indicates a good match to the
experimental values for 39 elements, corresponding to 12 out of 15 periodic
groups. This newly observed result opens up the possibility of further refining
the Lindemann melting criterion by stimulating analytical studies of the
Lindemann coefficient in the light of this newly discovered result
A RANGELAND GRASSHOPPER INSURANCE PROGRAM
The incidence of benefits and costs from controlling rangeland grasshoppers on public grazing lands poses problems of economic efficiency and distributional equity. Public grasshopper control programs operate like public disaster assistance. However, grasshopper infestations are an insurable risk. This article proposes a rangeland grasshopper insurance program which reduces the economic inefficiencies and distributional inequities of the existing program.Risk and Uncertainty,
The Effect of Tax Laws and the Cost of Capital on the Size of Newly Constructed Strip Shopping Centers
While the impact of tax policy and other economic variables on the total amount of construction has been widely studied, this paper proposes that these variables also affect the size distribution of the properties constructed. The basic intuition is that there is a lower bound to the economically feasible size of a project due to economies of scale in construction. Events favorable to construction, such as lower interest rates and more favorable tax treatment, relax this lower bound permitting the construction of smaller properties. We test this proposition using data on newly constructed neighborhood shopping centers in Clark County, Nevada during the period from 1971 to 1999.
The G alpha q and G alpha 11 proteins couple the thyrotropin-releasing hormone receptor to phospholipase C in GH3 rat pituitary cells
Thyrotropin-releasing hormone stimulates the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) in GH3 cell membranes. The stimulation of the phosphoinositide phospholipase C (PI/PLC) activity can be blocked by incubation of GH3 membranes with polyclonal antibodies directed against a peptide derived from the C-terminal region of G alpha q and G alpha 11. Antibodies directed against the C- terminal region of other G alpha-subunits had no detectable effect. The inhibition was specific since addition of the peptide that was used to prepare the antibody completely reversed the inhibition. Further evidence for the coupling of the TRH receptor to G alpha q or G alpha 11 comes from a reconstitution experiment in which human embryonic kidney cells were transiently transfected with cDNAs corresponding to the TRH receptor, G alpha q or G alpha 11. The PIP2 hydrolysis detected with membranes from cells that over-expressed the TRH receptor alone was low, however, co-expression with the G alpha q or G alpha 11 subunits produced a synergistic stimulation of PI-PLC activity. In contrast, co-expression of these alpha-subunits with the M2 muscarinic acetylcholine receptor induced a weak stimulation of PIP2 hydrolysis. The results presented here suggest that the TRH-dependent stimulation of PI-PLC in GH3 cells is mediated through the G-protein alpha- subunits, G alpha q and/or G alpha 11
Case records of the Massachusetts General Hospital. Case 1-2014. A 32-year-old man with loss of vision and a rash
Discrete Hamilton-Jacobi Theory
We develop a discrete analogue of Hamilton-Jacobi theory in the framework of
discrete Hamiltonian mechanics. The resulting discrete Hamilton-Jacobi equation
is discrete only in time. We describe a discrete analogue of Jacobi's solution
and also prove a discrete version of the geometric Hamilton-Jacobi theorem. The
theory applied to discrete linear Hamiltonian systems yields the discrete
Riccati equation as a special case of the discrete Hamilton-Jacobi equation. We
also apply the theory to discrete optimal control problems, and recover some
well-known results, such as the Bellman equation (discrete-time HJB equation)
of dynamic programming and its relation to the costate variable in the
Pontryagin maximum principle. This relationship between the discrete
Hamilton-Jacobi equation and Bellman equation is exploited to derive a
generalized form of the Bellman equation that has controls at internal stages.Comment: 26 pages, 2 figure
Intra-day Patterns in the Returns, Bidask Spereads, and Trading Volume of Stocks Traded on the New York Stock Exchange
Much research has demonstrated the existence of patterns in high-frequency equity returns, return volatility, bid-ask spreads and trading volume. In this paper, we employ a new test for detecting periodicities based on a signal coherence function. The technique is applied to the returns, bid-ask spreads, and trading volume of thirty stocks traded on the NYSE. We are able to confirm previous findings of an inverse J-shaped pattern in spreads and volume through the day. We also demonstrate that such intraday effects dominate day of the week seasonalities in spreads and volumes, while there are virtually no significant periodicities in the returns data. Our approach can also leads to a natural method for forecasting the time series, and we find that, particularly in the case of the volume series, the predictions are considerably more accurate than those from naïve methods.spectral analysis, peridocities, seasonality, intraday paterns, bid-ask spread, trading volume
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