657 research outputs found
Boundedness properties of fermionic operators
The fermionic second quantization operator is shown to be
bounded by a power of the number operator given that the operator
belongs to the -th von Neumann-Schatten class, . Conversely,
number operator estimates for imply von Neumann-Schatten
conditions on . Quadratic creation and annihilation operators are treated as
well.Comment: 15 page
Ultracoherence and Canonical Transformations
The (in)finite dimensional symplectic group of homogeneous canonical
transformations is represented on the bosonic Fock space by the action of the
group on the ultracoherent vectors, which are generalizations of the coherent
states.Comment: 24 page
Applications of Canonical Transformations
Canonical transformations are defined and discussed along with the
exponential, the coherent and the ultracoherent vectors. It is shown that the
single-mode and the -mode squeezing operators are elements of the group of
canonical transformations. An application of canonical transformations is made,
in the context of open quantum systems, by studying the effect of squeezing of
the bath on the decoherence properties of the system. Two cases are analyzed.
In the first case the bath consists of a massless bosonic field with the bath
reference states being the squeezed vacuum states and squeezed thermal states
while in the second case a system consisting of a harmonic oscillator
interacting with a bath of harmonic oscillators is analyzed with the bath being
initially in a squeezed thermal state.Comment: 14 page
Acute tropical pulmonary eosinophilia: characterization of the lower respiratory tract inflammation and its response to therapy
Although acute tropical pulmonary eosinophilia (TPE) is well
recognized as a manifestation of filarial infection, the processes
that mediate the abnormalities of the lung in TPE are unknown.
To evaluate the hypothesis that the derangements of the lower
respiratory tract in this disorder are mediated by inflammatory
cells in the local milieu we utilized bronchoalveolar lavage to
evaluate affected individuals before and after therapy. Inflaminatory
cells recovered from the lower respiratory tract of individuals
with acute, untreated TPE (a = 8) revealed a striking
eosinophilic alveolitis, with marked elevations in both the proportion
of eosinophils (TPE 54±5%; normal 2±5%; P < 0.001)
and the concentration of eosinophils in the recovered epithelial
lining fluid (ELF) (TPE 63±20 X 103/Al; normal 03±0.1
X 103/jl; P < 0.01). Importantly, when individuals (a = 5) with
acute TPE were treated with diethylcarbamazine (DEC), there
was a marked decrease of the lung eosinophils and concomitant
increase in lung function. These observations are consistent with
the concept that at least some of the abnormalities found in the
lung in acute TPE are mediated by an eosinophil-dominated inflammatory
process in the lower respiratory tract
The Emerging Story of Disability Associated with Lymphatic Filariasis: A Critical Review
Globally, 40 million people live with the chronic effects of lymphatic filariasis (LF), making it the second leading cause of disability in the world. Despite this, there is limited research into the experiences of people living with the disease. This review summarises the research on the experiences of people living with LF disability. The review highlights the widespread social stigma and oppressive psychological issues that face most people living with LF-related disability. Physical manifestations of LF make daily activities and participation in community life difficult. The findings confirm the need for the Global Programme to Eliminate Lymphatic Filariasis (GPELF) to support morbidity management activities that address the complex biopsychosocial issues that people living with LF-related disability face
Site-specific incorporation of phosphotyrosine using an expanded genetic code.
Access to phosphoproteins with stoichiometric and site-specific phosphorylation status is key to understanding the role of protein phosphorylation. Here we report an efficient method to generate pure, active phosphotyrosine-containing proteins by genetically encoding a stable phosphotyrosine analog that is convertible to native phosphotyrosine. We demonstrate its general compatibility with proteins of various sizes, phosphotyrosine sites and functions, and reveal a possible role of tyrosine phosphorylation in negative regulation of ubiquitination
Seabed geomorphology: a two-part classification system
The BGS has developed a two-
part classification system
(‘Morphology’ and ‘Geomorphology’)
to facilitate work on a new ‘S
eabed Geomorphology’ mapping initia
tive, and this classification
system is the focus of this report. As stated in
the Foreword, the rationale
and the basic framework
of the classification system were conceived and es
tablished within BGS, but
recent collaboration
within the
MAREANO
-Norway,
INFOMAR
-Ireland, and
MAREMAP
-UK (MIM) partnership
has led to significant improvement of the classifi
cation system, and this report. To further support
this effort, existing BGS GIS tools (SIGMA) ha
ve been adapted to apply this two-part
classification system for more efficient geom
orphological mapping in the marine environment.
This report:
provides a brief background on seabed mapping
and characterisation, as well as how this
science has been addressed
historically within BGS;
describes the current motiva
tion to conduct seabed geom
orphological mapping, and the
requirement for a new set of t
ools to facilitate this work;
describes the logical framework that
underpins the classification system;
outlines the attributes of the classification
system, how it can be applied, and discusses
the advantages and limitations of the approach.
It is anticipated that through testing and usage,
the classification syst
em will be revised and
improved over time, with updated versions released
through MIM partnershi
p. It is also planned
that a further ‘user guide’ report
will be produced for the classifi
cation system and the GIS tools,
including thematic details (e.g.
background information on ‘coastal’
or ‘glacial’ features) and a
feature glossary
A mathematical model for breath gas analysis of volatile organic compounds with special emphasis on acetone
Recommended standardized procedures for determining exhaled lower respiratory
nitric oxide and nasal nitric oxide have been developed by task forces of the
European Respiratory Society and the American Thoracic Society. These
recommendations have paved the way for the measurement of nitric oxide to
become a diagnostic tool for specific clinical applications. It would be
desirable to develop similar guidelines for the sampling of other trace gases
in exhaled breath, especially volatile organic compounds (VOCs) which reflect
ongoing metabolism. The concentrations of water-soluble, blood-borne substances
in exhaled breath are influenced by: (i) breathing patterns affecting gas
exchange in the conducting airways; (ii) the concentrations in the
tracheo-bronchial lining fluid; (iii) the alveolar and systemic concentrations
of the compound. The classical Farhi equation takes only the alveolar
concentrations into account. Real-time measurements of acetone in end-tidal
breath under an ergometer challenge show characteristics which cannot be
explained within the Farhi setting. Here we develop a compartment model that
reliably captures these profiles and is capable of relating breath to the
systemic concentrations of acetone. By comparison with experimental data it is
inferred that the major part of variability in breath acetone concentrations
(e.g., in response to moderate exercise or altered breathing patterns) can be
attributed to airway gas exchange, with minimal changes of the underlying blood
and tissue concentrations. Moreover, it is deduced that measured end-tidal
breath concentrations of acetone determined during resting conditions and free
breathing will be rather poor indicators for endogenous levels. Particularly,
the current formulation includes the classical Farhi and the Scheid series
inhomogeneity model as special limiting cases.Comment: 38 page
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