18,239 research outputs found
Blood oxygen saturation determined by transmission spectrophotometry of hemolyzed blood samples
Use of the Lambert-Beer Transmission Law determines blood oxygen saturation of hemolyzed blood samples. This simplified method is based on the difference in optical absorption properties of hemoglobin and oxyhemoglobin
Improved sample capsule for determination of oxygen in hemolyzed blood
Sample capsule for determination of oxygen in hemolyzed blood consists of a measured section of polytetrafluoroethylene tubing equipped at each end with a connector and a stopcock valve. This method eliminates errors from air entrainment or from the use of mercury or syringe lubricant
The Geography of Output Volatility
This paper examines the structural determinants of output volatility in developing countries, and especially the roles of geography and institutions. We investigate the volatility effects of market access, climate variability, the geographic predisposition to trade, and various measures of institutional quality. We find an especially important role for market access: remote countries are more likely to have undiversified exports and to experience greater volatility in output growth. Our results are based on Bayesian methods that allow us to address formally the problem of model uncertainty and to examine robustness across a wide range of specifications.Volatility, Geography, Institutions, Bayesian Model Averaging
Efficient separation of the orbital angular momentum eigenstates of light
Orbital angular momentum (OAM) of light is an attractive degree of freedom
for funda- mentals studies in quantum mechanics. In addition, the discrete
unbounded state-space of OAM has been used to enhance classical and quantum
communications. Unambiguous mea- surement of OAM is a key part of all such
experiments. However, state-of-the-art methods for separating single photons
carrying a large number of different OAM values are limited to a theoretical
separation efficiency of about 77 percent. Here we demonstrate a method which
uses a series of unitary optical transformations to enable the measurement of
lights OAM with an experimental separation efficiency of more than 92 percent.
Further, we demonstrate the separation of modes in the angular position basis,
which is mutually unbiased with respect to the OAM basis. The high degree of
certainty achieved by our method makes it particu- larly attractive for
enhancing the information capacity of multi-level quantum cryptography systems
Geometrical Aspects Of BRST Cohomology In Augmented Superfield Formalism
In the framework of augmented superfield approach, we provide the geometrical
origin and interpretation for the nilpotent (anti-)BRST charges, (anti-)co-BRST
charges and a non-nilpotent bosonic charge. Together, these local and conserved
charges turn out to be responsible for a clear and cogent definition of the
Hodge decomposition theorem in the quantum Hilbert space of states. The above
charges owe their origin to the de Rham cohomological operators of differential
geometry which are found to be at the heart of some of the key concepts
associated with the interacting gauge theories. For our present review, we
choose the two -dimensional (2D) quantum electrodynamics (QED) as a
prototype field theoretical model to derive all the nilpotent symmetries for
all the fields present in this interacting gauge theory in the framework of
augmented superfield formulation and show that this theory is a {\it unique}
example of an interacting gauge theory which provides a tractable field
theoretical model for the Hodge theory.Comment: LaTeX file, 25 pages, Ref. [49] updated, correct page numbers of the
Journal are give
Production of in electron positron collisions
is an atom of simple hydrogenlike structure similar to
positronium and . In this paper energy levels and
decay widths of different decay channels of are given. Cross
section of production of this atomic system in annihilation taking
into account radiative corrections is calculated. According to our estimates
886 atoms may be produced at BEPCII and 29
atoms are produced at VEPP-4M under the present experimental
conditions.Comment: 5 pages, submitted to Int. Jour. Mod. Phys.
Nonmodal energy growth and optimal perturbations in compressible plane Couette flow
Nonmodal transient growth studies and estimation of optimal perturbations
have been made for the compressible plane Couette flow with three-dimensional
disturbances. The maximum amplification of perturbation energy over time,
, is found to increase with increasing Reynolds number ,
but decreases with increasing Mach number . More specifically, the optimal
energy amplification (the supremum of over both the
streamwise and spanwise wavenumbers) is maximum in the incompressible limit and
decreases monotonically as increases. The corresponding optimal streamwise
wavenumber, , is non-zero at M=0, increases with increasing
, reaching a maximum for some value of and then decreases, eventually
becoming zero at high Mach numbers. While the pure streamwise vortices are the
optimal patterns at high Mach numbers, the modulated streamwise vortices are
the optimal patterns for low-to-moderate values of the Mach number. Unlike in
incompressible shear flows, the streamwise-independent modes in the present
flow do not follow the scaling law , the reasons
for which are shown to be tied to the dominance of some terms in the linear
stability operator. Based on a detailed nonmodal energy analysis, we show that
the transient energy growth occurs due to the transfer of energy from the mean
flow to perturbations via an inviscid {\it algebraic} instability. The decrease
of transient growth with increasing Mach number is also shown to be tied to the
decrease in the energy transferred from the mean flow () in
the same limit
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