24,210 research outputs found
Mach-Zehnder optical configuration with Brewster window and two quarter-wave plates
Configuration is improvement because of the following: It provides higher efficiency. It reduces or eliminates feedthrough of untranslated local oscillator, which would produce a beat signal at shifted frequency of translator. When used without translator and with low-power detector, telescope secondary mirror reflects portion of output to local oscillator
Outcomes of a specialist weight management programme in the UK national health service: prospective study of 1838 patients
Objectives There is limited evidence on the effectiveness of weight management programmes provided within routine healthcare and inconsistent use of outcome measures. Our aim was to evaluate a large National Health Service (NHS) weight management service and report absolute and proportional weight losses over 12 months.<p></p>
Design Prospective observational study.<p></p>
Setting Glasgow and Clyde Weight Management Service (GCWMS), which provides care for residents of NHS Greater Glasgow and Clyde area (population 1.2 million).<p></p>
Participants All patients who began GCWMS between 1 October 2008 and 30 September 2009.<p></p>
Interventions Structured educational lifestyle programme employing cognitive behavioural therapy, 600 kcal deficit diet, physical activity advice, lower calorie diet and pharmacotherapy.<p></p>
Primary and secondary outcomes measures Baseline observation carried forward (BOCF), last observation carried forward (LOCF) and changes in programme completers reported using outcomes of absolute 5 kg and 5% weight losses and mean weight changes at a variety of time points.<p></p>
Results 6505 referrals were made to GCWMS, 5637 were eligible, 3460 opted in and 1916 (34%) attended a first session. 78 patients were excluded from our analysis on 1838 patients. 72.9% of patients were women, mean age of all patients at baseline was 49.1 years, 43.3% lived in highly socioeconomically deprived areas and mean weights and body mass indices at baseline were 118.1 kg and 43.3 kg/m2, respectively. 26% lost ≥5 kg by the end of phase 1, 30% by the end of phase 2 and 28% by the end of phase 3 (all LOCF). Weight loss was more successful among men, particularly those ≤29 years old.<p></p>
Conclusions Routine NHS weight management services may achieve moderate weight losses through a comprehensive evidence-based dietary, activity and behavioural approach including psychological care. Weight losses should be reported using a range of outcome measures so that the effectiveness of different services can be compared
On the Theory of Superfluidity in Two Dimensions
The superfluid phase transition of the general vortex gas, in which the
circulations may be any non-zero integer, is studied. When the net circulation
of the system is not zero the absence of a superfluid phase is shown. When the
net circulation of the vortices vanishes, the presence of off-diagonal long
range order is demonstrated and the existence of an order parameter is
proposed. The transition temperature for the general vortex gas is shown to be
the Kosterlitz---Thouless temperature. An upper bound for the average vortex
number density is established for the general vortex gas and an exact
expression is derived for the Kosterlitz---Thouless ensemble.Comment: 22 pages, one figure, written in plain TeX, published in J. Phys. A24
(1991) 502
The NAD(P)H-utilizing glutamate dehydrogenase of Bacteroides thetaiotamicron belongs to enzyme family I, and its activity is affected by trans-acting gene(s) positioned downstream of gdhA
Previous studies have suggested that regulation of the enzymes of ammonia assimilation in human colonic Bacteroides species is coordinated differently than in other eubacteria. The gene encoding an NAD(P)H-dependent glutamate dehydrogenase (gdhA) in Bacteroides thetaiotaomicron was tinned and expressed in Escherichia coli by mutant complementation from the recombinant plasmid pANS100. Examination of the predicted GdhA amino acid sequence revealed that this enzyme possesses motifs typical of the family I-type hexameric GDH proteins. Northern blot analysis with a gdhA-specific probe indicated that a single transcript with an electrophoretic mobility of ~1.6 kb was produced in both B. thetaiotaomicron and E. coli gdhA transformants. Although gdhA transcription was unaffected, no GdhA enzyme activity could be detected in E. coli transformants when smaller DNA fragments from pANS100, which contained the entire gdhA gene, were analyzed. Enzyme activity was restored if these E. coli strains were cotransformed with a second plasmid, which contained a 3-kb segment of DNA located downstream of the gdhA coding region. Frameshift mutagenesis within the DNA downstream of gdhA in pANS100 also resulted in the loss of GdhA enzyme activity. Collectively, these results are interpreted as evidence for the role of an additional gene product(s) in modulating the activity of GDH enzyme activity. Insertional mutagenesis experiments which led to disruption of the gdhA gene on the B. thetaiotaomicron chromosome indicated that gdhA mutants were not glutamate auxotrophs, but attempts to isolate similar mutants with insertion mutations in the region downstream of the gdhA gene were unsuccessful
Internal wave pressure, velocity, and energy flux from density perturbations
Determination of energy transport is crucial for understanding the energy
budget and fluid circulation in density varying fluids such as the ocean and
the atmosphere. However, it is rarely possible to determine the energy flux
field , which requires simultaneous measurements of
the pressure and velocity perturbation fields, and . We present
a method for obtaining the instantaneous from density
perturbations alone: a Green's function-based calculation yields , and
is obtained by integrating the continuity equation and the
incompressibility condition. We validate our method with results from
Navier-Stokes simulations: the Green's function method is applied to the
density perturbation field from the simulations, and the result for
is found to agree typically to within with
computed directly using and from the Navier-Stokes
simulation. We also apply the Green's function method to density perturbation
data from laboratory schlieren measurements of internal waves in a stratified
fluid, and the result for agrees to within with results from
Navier-Stokes simulations. Our method for determining the instantaneous
velocity, pressure, and energy flux fields applies to any system described by a
linear approximation of the density perturbation field, e.g., to small
amplitude lee waves and propagating vertical modes. The method can be applied
using our Matlab graphical user interface EnergyFlux
Characterization of the Interaction between the Herpes Simplex Virus Type I Fc Receptor and Immunoglobulin G
Herpes simplex virus type I (HSV-1) virions and HSV-1-infected cells bind to human immunoglobulin G (hIgG) via its Fc region. A complex of two surface glycoproteins encoded by HSV-1, gE and gI, is responsible for Fc binding. We have co-expressed soluble truncated forms of gE and gI in Chinese hamster ovary cells. Soluble gE-gI complexes can be purified from transfected cell supernatants using a purification scheme that is based upon the Fc receptor function of gE-gI. Using gel filtration and analytical ultracentrifugation, we determined that soluble gE-gI is a heterodimer composed of one molecule of gE and one molecule of gI and that gE-gI heterodimers bind hIgG with a 1:1 stoichiometry. Biosensor-based studies of the binding of wild type or mutant IgG proteins to soluble gE-gI indicate that histidine 435 at the CH2-CH3 domain interface of IgG is a critical residue for IgG binding to gE-gI. We observe many similarities between the characteristics of IgG binding by gE-gI and by rheumatoid factors and bacterial Fc receptors such as Staphylococcus aureus protein A. These observations support a model for the origin of some rheumatoid factors, in which they represent anti-idiotypic antibodies directed against antibodies to bacterial and viral Fc receptors
Assessment of Thermographic Imaging Systems on Small Unmanned Aerial Systems (sUAS) to Identify Artificial Grassland Bird Nests
Grassland bird populations can be good indicator species of ecosystem health. However, their populations are declining at greater rates than any other group of birds. A well-established method of monitoring rapidly disappearing bird populations is by locating and identifying active nests. Studies quantifying grassland birds tend to have low statistical power due to low sample sizes, high labor costs, and high levels of disturbance - associated with difficulty finding nests. However, advances in small unmanned aerial systems (sUAS) and thermographic imaging technologies have the potential to improve efficiency and accuracy of locating nests, while causing minimal disruption. Early research has evaluated nest detectability using a thermal imaging system equipped to a sUAS. The sUAS was flown at three different altitudes to detect simulated nests at incremental depths in monoculture grass stand canopies. This study evaluated nest detection accuracy using visual assessment of two different types of thermal imagery. The first type of imagery used third-party software to create a stitched thermal map of the research area, while the second method utilized real-time video feed from the thermal sensor to identify simulated nest locations. Both methodologies were tested in a blind evaluation, using five evaluators and two replications. Results from this study have suggested that mapping software does not optimize nest detectability and identification, and the analysis of videos proves to be a much more precise way to detect and identify nests
Lifting of the Vlasov-Maxwell Bracket by Lie-transform Method
The Vlasov-Maxwell equations possess a Hamiltonian structure expressed in
terms of a Hamiltonian functional and a functional bracket. In the present
paper, the transformation ("lift") of the Vlasov-Maxwell bracket induced by the
dynamical reduction of single-particle dynamics is investigated when the
reduction is carried out by Lie-transform perturbation methods. The ultimate
goal of this work is to derive explicit Hamiltonian formulations for the
guiding-center and gyrokinetic Vlasov-Maxwell equations that have important
applications in our understanding of turbulent magnetized plasmas. Here, it is
shown that the general form of the reduced Vlasov-Maxwell equations possesses a
Hamiltonian structure defined in terms of a reduced Hamiltonian functional and
a reduced bracket that automatically satisfies the standard bracket properties.Comment: 39 page
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