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Airborne environmental injuries and human health.
The concept that the environment in which we live can have detrimental effects on our health has existed for centuries. Obvious examples of substances that can cause human diseases include infectious agents, poisons, chemicals and other noxious agents, drugs, and physical stimuli such as bright lights and loud sounds. Some less obvious agents can include allergens, nontangible agents such as colorless, odorless gases and aerosolized toxins. In recent decades, humans have developed various new materials and compounds. Additionally, we are now producing known compounds, and even naturally occurring substances, in vastly increased amounts. Many of these substances are generally believed to threaten the health of our environment. However, there is also a considerable amount of hype and exaggeration regarding some of these agents (e.g., mold) that is unsubstantiated. This article extensively reviews the data on a large number of airborne-related illnesses and attempted to place scientific reality in the context of clinical medicine
Excitons in carbon nanotubes: an ab initio symmetry-based approach
The optical absorption spectrum of the carbon (4,2) nanotube is computed
using an ab-initio many-body approach which takes into account excitonic
effects. We develop a new method involving a local basis set which is symmetric
with respect to the screw symmetry of the tube. Such a method has the
advantages of scaling faster than plane-wave methods and allowing for a precise
determination of the symmetry character of the single particle states,
two-particle excitations, and selection rules. The binding energy of the
lowest, optically active states is approximately 0.8 eV. The corresponding
exciton wavefunctions are delocalized along the circumference of the tube and
localized in the direction of the tube axis.Comment: 4 pages, 1 LaTex file + 4 eps figure
Unique molecular identifier-based high-resolution HLA typing and transcript quantitation using long-read sequencing
HLA typing provides essential results for stem cell and solid organ transplants, as well as providing diagnostic benefits for various rheumatology, gastroenterology, neurology, and infectious diseases. It is becoming increasingly clear that understanding the expression of patient HLA transcripts can provide additional benefits for many of these same patient groups. Our study cohort was evaluated using a long-read RNA sequencing methodology to provide rapid HLA genotyping results and normalized HLA transcript expression. Our assay used NGSEngine to determine the HLA genotyping result and normalized mRNA transcript expression using Athlon2. The assay demonstrated an excellent concordance rate of 99.7%. Similar to previous studies, for the class I loci, patients demonstrated significantly lower expression o
ROMA (Rank-Ordered Multifractal Analysis) for intermittent fluctuations with global crossover behavior
Rank-Ordered Multifractal Analysis (ROMA), a recently developed technique
that combines the ideas of parametric rank ordering and one parameter scaling
of monofractals, has the capabilities of deciphering the multifractal
characteristics of intermittent fluctuations. The method allows one to
understand the multifractal properties through rank-ordered scaling or
non-scaling parametric variables. The idea of the ROMA technique is applied to
analyze the multifractal characteristics of the auroral zone electric field
fluctuations observed by SIERRA. The observed fluctuations span across
contiguous multiple regimes of scales with different multifractal
characteristics. We extend the ROMA technique such that it can take into
account the crossover behavior -- with the possibility of collapsing
probability distributions functions (PDFs) -- over these contiguous regimes.Comment: 24 pages, 18 figure
QCD Radiative Corrections to the Leptonic Decay Rate of the B_c Meson
The QCD radiative corrections to the leptonic decay rate of the meson
are calculated using the formalism of nonrelativistic QCD (NRQCD) to separate
short-distance and long-distance effects. The decay constant is factored
into a sum of NRQCD matrix elements each multiplied by a short-distance
coefficient. The short-distance coefficient for the leading matrix element is
calculated to order by matching a perturbative calculation in full
QCD with the corresponding perturbative calculation in NRQCD. This
short-distance correction decreases the leptonic decay rate by approximately
.Comment: Changed Eq. 2 to read 1/(8 \pi), put in a missing i M_{B_c} in Eq.
18, and put in a normalisation factor of 2 M_{B_c} in Eq. 19
Spin- and charge-density waves in the Hartree-Fock ground state of the two-dimensional Hubbard model
The ground states of the two-dimensional repulsive Hubbard model are studied
within the unrestricted Hartree-Fock (UHF) theory. Magnetic and charge
properties are determined by systematic, large-scale, exact numerical
calculations, and quantified as a function of electron doping . In the
solution of the self-consistent UHF equations, multiple initial configurations
and simulated annealing are used to facilitate convergence to the global
minimum. New approaches are employed to minimize finite-size effects in order
to reach the thermodynamic limit. At low to moderate interacting strengths and
low doping, the UHF ground state is a linear spin-density wave (l-SDW), with
antiferromagnetic order and a modulating wave. The wavelength of the modulating
wave is . Corresponding charge order exists but is substantially weaker
than the spin order, hence holes are mobile. As the interaction is increased,
the l-SDW states evolves into several different phases, with the holes
eventually becoming localized. A simple pairing model is presented with
analytic calculations for low interaction strength and small doping, to help
understand the numerical results and provide a physical picture for the
properties of the SDW ground state. By comparison with recent many-body
calculations, it is shown that, for intermediate interactions, the UHF solution
provides a good description of the magnetic correlations in the true ground
state of the Hubbard model.Comment: 13 pages, 17 figure, 0 table
Sampling-based Exploration for Reinforcement Learning of Dexterous Manipulation
In this paper, we present a novel method for achieving dexterous manipulation
of complex objects, while simultaneously securing the object without the use of
passive support surfaces. We posit that a key difficulty for training such
policies in a Reinforcement Learning framework is the difficulty of exploring
the problem state space, as the accessible regions of this space form a complex
structure along manifolds of a high-dimensional space. To address this
challenge, we use two versions of the non-holonomic Rapidly-Exploring Random
Trees algorithm; one version is more general, but requires explicit use of the
environment's transition function, while the second version uses
manipulation-specific kinematic constraints to attain better sample efficiency.
In both cases, we use states found via sampling-based exploration to generate
reset distributions that enable training control policies under full dynamic
constraints via model-free Reinforcement Learning. We show that these policies
are effective at manipulation problems of higher difficulty than previously
shown, and also transfer effectively to real robots. Videos of the real-hand
demonstrations can be found on the project website:
https://sbrl.cs.columbia.edu/Comment: 10 pages, 6 figures, submitted to Robotics Science & Systems 202
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