43,883 research outputs found
Fluid injection device for high-pressure systems
Screw activated device, consisting of a compressor, shielded replaceable ampules, a multiple-element rubber gland, and a specially constructed fluid line fitting, injects measured amounts of fluids into a pressurized system. It is sturdy and easily manipulated
Pedestrian demand modelling of large cities: an applied example from London
This paper introduces a methodology for the development of city wide pedestrian demand models and shows its application to London. The approach used for modelling is Multiple Regression Analysis of independent variables against the dependent variable of observed pedestrian flows. The test samples were from manual observation studies of average total pedestrian flow per hour on 237 sample sites. The model will provide predicted flow values for all 7,526 street segments in the 25 square kilometres of Central London. It has been independently validated by Transport for London and is being tested against further observation data. The longer term aim is to extend the model to the entire greater London area and to incorporate additional policy levers for use as a transport planning and evaluation tool
A Life-Cycle Overlapping-Generations Model of the Small Open Economy
In this paper we construct an overlapping generations model for the small open economy incorporating a realistic description of the mortality process. With agedependent mortality, the typical life-cycle pattern of consumption and saving results from the maximizing behaviour of individual households. Our ?Blanchard-Yaari-Modigliani?model is used to analytically study a number of typical shocks affecting the small open economy, namely a balanced-budget public spending shock, a temporary Ricardian tax cut, and an interest rate shock. The demographic details matter a lot?both the impulse-response functions and the welfare profiles (associated with the different shocks) are critically affected by them. These demographic details furthermore do not wash out in the aggregate. The model is flexible and can be applied to a wide variety of theoretical and policy issues.
Ecologic Relationships Between Bacteria and Algae in Mass Culture
Ecological relationships between bacteria and algae in mass cultur
Taking A Stand: The Effects Of Standing Desks On Task Performance And Engagement
Time spent sitting is associated with negative health outcomes, motivating some individuals to adopt standing desk workstations. This study represents the first investigation of the effects of standing desk use on reading comprehension and creativity. In a counterbalanced, within-subjects design, 96 participants completed reading comprehension and creativity tasks while both sitting and standing. Participants self-reported their mood during the tasks and also responded to measures of expended effort and task difficulty. In addition, participants indicated whether they expected that they would perform better on work-relevant tasks while sitting or standing. Despite participants’ beliefs that they would perform worse on most tasks while standing, body position did not affect reading comprehension or creativity performance, nor did it affect perceptions of effort or difficulty. Mood was also unaffected by position, with a few exceptions: Participants exhibited greater task engagement (i.e., interest, enthusiasm, and alertness) and less comfort while standing rather than sitting. In sum, performance and psychological experience as related to task completion were nearly entirely uninfluenced by acute (~30-min) standing desk use. View Full-Tex
Clinical and cost-effectiveness of capecitabine and tegafur with uracil for the treatment of metastatic colorectal cancer: systematic review and economic evaluation
Objectives:
To evaluate the clinical and costeffectiveness
of capecitabine and tegafur with uracil
(UFT/LV) as first-line treatments for patients with
metastatic colorectal cancer, as compared with 5-
fluorouracil/folinic acid (5-FU/FA) regimens.
Data sources: Electronic databases, reference lists of
relevant articles and sponsor submissions were also
consulted.
Review methods:
Systematic searches, selection
against criteria and quality assessment were performed
to obtain data from relevant studies. Costs were
estimated through resource-use data taken from the
published trials and the unpublished sponsor
submissions. Unit costs were taken from published
sources, where available. An economic evaluation was
undertaken to compare the cost-effectiveness of
capecitabine and UFT/LV with three intravenous 5-
FU/LV regimens widely used in the UK: the Mayo, the
modified de Gramont regimen and the inpatient de
Gramont regimens.
Results:
The evidence suggests that treatment with
capecitabine improves overall response rates and has
an improved adverse effect profile in comparison with
5-FU/LV treatment with the Mayo regimen, with the
exception of hand–foot syndrome. Time to disease
progression or death after treatment with UFT/LV in
one study appears to be shorter than after treatment
with 5-FU/LV with the Mayo regimen, although it also
had an improved adverse effect profile. Neither
capecitabine nor UFT/LV appeared to improve healthrelated
quality of life. Little information on patient
preference was available for UFT/LV, but there was
indicated a strong preference for this over 5-FU/LV.
The total cost of capecitabine and UFT/LV treatments
were estimated at £2111 and £3375, respectively,
compared with the total treatment cost for the Mayo
regimen of £3579. Cost estimates were also presented
for the modified de Gramont and inpatient de Gramont
regimens. These were £3684 and £6155, respectively.
No survival advantage was shown in the RCTs of the
oral drugs against the Mayo regimen. Cost savings of
capecitabine and UFT/LV over the Mayo regimen were
estimated to be £1461 and £209, respectively. Drug
acquisition costs were higher for the oral therapies
than for the Mayo regimen, but were offset by lower
administration costs. Adverse event treatment costs
were similar across the three regimens. It was inferred
that there was no survival difference between the oral
drugs and the de Gramont regimens. Cost savings of
capecitabine and UFT/LV over the modified de
Gramont regimen were estimated to be £1353 and
£101, respectively, and over the inpatient de Gramont
regimen were estimated to be £4123 and £2870,
respectively.
Conclusions:
The results show that there are cost
savings associated with the use of oral therapies. No
survival difference has been proven between the oral
drugs and the Mayo regimen. In addition, no evidence
of a survival difference between the Mayo regimen and
the de Gramont regimens has been identified.
However, improved progression-free survival and an
improved adverse event profile have been shown for
the de Gramont regimen over the Mayo regimen.
Further research is recommended into the following
areas: quality of life data should be included in trials of
colorectal cancer treatments; the place of effective oral
treatments in the treatment of colorectal cancer, the
safety mechanisms needed to ensure compliance and
the monitoring of adverse effects; the optimum
duration of treatment; the measurement of patient
preference; and a phase III comparative trial of
capecitabine and UFT/LV versus modified de Gramont
treatment to determine whether there was any survival
advantage and to collate the necessary economic data
An airborne remote sensing system for urban air quality
Several NASA sponsored remote sensors and possible airborne platforms were evaluated. Outputs of dispersion models for SO2 and CO pollution in the Washington, D.C. area were used with ground station data to establish the expected performance and limitations of the remote sensors. Aircraft/sensor support requirements are discussed. A method of optimum flight plan determination was made. Cost trade offs were performed. Conclusions about the implementation of various instrument packages as parts of a comprehensive air quality monitoring system in Washington are presented
Remote sensing of changes in morphology and physiology of trees under stress Annual progress report
Remote sensing of morphological and physiological changes in trees under stres
Calculating photonic Green's functions using a non-orthogonal finite difference time domain method
In this paper we shall propose a simple scheme for calculating Green's
functions for photons propagating in complex structured dielectrics or other
photonic systems. The method is based on an extension of the finite difference
time domain (FDTD) method, originally proposed by Yee, also known as the
Order-N method, which has recently become a popular way of calculating photonic
band structures. We give a new, transparent derivation of the Order-N method
which, in turn, enables us to give a simple yet rigorous derivation of the
criterion for numerical stability as well as statements of charge and energy
conservation which are exact even on the discrete lattice. We implement this
using a general, non-orthogonal co-ordinate system without incurring the
computational overheads normally associated with non-orthogonal FDTD.
We present results for local densities of states calculated using this method
for a number of systems. Firstly, we consider a simple one dimensional
dielectric multilayer, identifying the suppression in the state density caused
by the photonic band gap and then observing the effect of introducing a defect
layer into the periodic structure. Secondly, we tackle a more realistic example
by treating a defect in a crystal of dielectric spheres on a diamond lattice.
This could have application to the design of super-efficient laser devices
utilising defects in photonic crystals as laser cavities.Comment: RevTex file. 10 pages with 8 postscript figures. Submitted to Phys
Rev
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