10,520 research outputs found
Towards variance-matrix characterization of complementarity relations in a continuous variable system
We discuss complementarity relations in a bipartite continuous variable
system. Building up from the work done on discrete d-dimensional systems, we
prove that for symmetric two-mode states, quantum complementarity relations can
be put in a simple relation with the elements of the variance matrix. When this
condition is not satisfied, such a connection becomes non-trivial. Our
investigation is the first step towards an operative characterization of the
complementarity in a scenario that has not been investigated so far.Comment: 7 pages, 4 figures, RevTeX
Asteroseismic effects in close binary stars
Turbulent processes in the convective envelopes of the sun and stars have
been shown to be a source of internal acoustic excitations. In single stars,
acoustic waves having frequencies below a certain cutoff frequency propagate
nearly adiabatically and are effectively trapped below the photosphere where
they are internally reflected. This reflection essentially occurs where the
local wavelength becomes comparable to the pressure scale height. In close
binary stars, the sound speed is a constant on equipotentials, while the
pressure scale height, which depends on the local effective gravity, varies on
equipotentials and may be much greater near the inner Lagrangian point (L_1).
As a result, waves reaching the vicinity of L_1 may propagate unimpeded into
low density regions, where they tend to dissipate quickly due to non-linear and
radiative effects. We study the three dimensional propagation and enhanced
damping of such waves inside a set of close binary stellar models using a WKB
approximation of the acoustic field. We find that these waves can have much
higher damping rates in close binaries, compared to their non-binary
counterparts. We also find that the relative distribution of acoustic energy
density at the visible surface of close binaries develops a ring-like feature
at specific acoustic frequencies and binary separations
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Lepidobatrachus laevis
Number of Pages: 16Integrative BiologyGeological Science
Economies of Scale for Real Estate Investment Trusts
Using the translog cost function to estimate economies of scale for a sample of Real Estate Investment Trusts for the years 1992-1994, we find significant evidence that economies of scale exist for REITs for all years examined. The results show that measurement of scale economies is sensitive to the model used for the measurement. Individual characteristics of the REIT, such as type of management and degree of leverage, affect the magnitude of the scale economy. Additional variables accounting for property type diversification and geographic influences have little additional impact on the measured scale economies. Finally, the measured economies of scale for REITs vary considerably over time.
US and foreign alloy cross-reference database
Marshall Space Flight Center and other NASA installations have a continuing requirement for materials data from other countries involved with the development of joint international Spacelab experiments and other hardware. This need includes collecting data for common alloys to ascertain composition, physical properties, specifications, and designations. This data is scattered throughout a large number of specification statements, standards, handbooks, and other technical literature which make a manual search both tedious and often limited in extent. In recognition of this problem, a computerized database of information on alloys was developed along with the software necessary to provide the desired functions to access this data. The intention was to produce an initial database covering aluminum alloys, along with the program to provide a user-interface to the data, and then later to extend and refine the database to include other nonferrous and ferrous alloys
Maintenance of Residential Rental Property: An Empirical Analysis
The maintenance costs of 137 residential rental properties in northwestern South Carolina are analyzed. The results show that maintenance cost per square foot increases with property age, tenant turnover, certain amenities, and for higher-rent properties. Compared to other property types, apartments exhibit higher maintenance costs per square foot with larger complexes showing lower per square foot maintenance costs than smaller complexes. This cost economy suggests added value to rental housing for larger complexes. Owners of multiple properties are found to pay higher maintenance costs. Finally, there is no observed relationship between absentee ownership and the level of property maintenance.
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Identification of the expressome by machine learning on omics data.
Accurate annotation of plant genomes remains complex due to the presence of many pseudogenes arising from whole-genome duplication-generated redundancy or the capture and movement of gene fragments by transposable elements. Machine learning on genome-wide epigenetic marks, informed by transcriptomic and proteomic training data, could be used to improve annotations through classification of all putative protein-coding genes as either constitutively silent or able to be expressed. Expressed genes were subclassified as able to express both mRNAs and proteins or only RNAs, and CG gene body methylation was associated only with the former subclass. More than 60,000 protein-coding genes have been annotated in the reference genome of maize inbred B73. About two-thirds of these genes are transcribed and are designated the filtered gene set (FGS). Classification of genes by our trained random forest algorithm was accurate and relied only on histone modifications or DNA methylation patterns within the gene body; promoter methylation was unimportant. Other inbred lines are known to transcribe significantly different sets of genes, indicating that the FGS is specific to B73. We accurately classified the sets of transcribed genes in additional inbred lines, arising from inbred-specific DNA methylation patterns. This approach highlights the potential of using chromatin information to improve annotations of functional genes
Small RNAs: How Seeds Remember To Obey Their Mother
SummaryThe endosperm is one of two products from the double fertilization event that occurs during sexual reproduction in flowering plants. A series of recent reports highlights the unusual genetic regulatory mechanisms that occur in endosperm and suggests a role for transposon regulation in imprinting
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