150 research outputs found
Work Journey Rescheduling - Report of Surveys.
In order to model the possible effects of rescheduling the work journey on city centre peak period traffic congestion, it was necessary to obtain information about the current employment position in the city centre, and about traffic conditions in the peak period. To this end, a series of surveys were designed and implemented to collect information from a stratified sample of centrally located employers; a sample of their employees; and about traffic conditions between the hours of 07.30 and 09.30 along selected routes leading into the city centre.
Problems in running the surveys were encountered and overcome, and the resulting information covered:
- Employee numbers, their permitted work hours, and the type of schedule worked per employer.
- The Standard Industrial Classification (SIC) of each employer.
- Car parking facilities provided by employer.
- Bus facilities provided by employer.
- Origin of employees' journey to work.
- Mode(s) used in employees' journey to work.
- Employees' actual arrival at and start work times, together with departure from work time, for the week preceeding the survey.
- Personal characteristics of employees.
- Structure of employees' households.
- Journey times and traffic flows along selected corridors.
The data thus collected was used to provide a base situation against which modelled alternative work hour strategies could be tested
Car Sharing and Peak Spreading Studies in Sheffield: Final Report.
This Study of two firms in Sheffield city centre has been carried out under a contract with LTR2 Division of the Department of Transport, dated 28th March 1980. The Department of Transport has been interested for some time in various aspects of car-sharing, and the impact on car sharing of different work hour arrangements, and had previously carried out surveys of car-sharers in Government offices at Longbenton, Newcastle upon Tyne (TAU 1977) and Llanishen, Cardiff (TAU 1979) where flexible working hours were in operation. This study was designed as a continuation of those studies, in a city centre area where car parking was severely restricted. The prime objective was to measure levels of car sharing in locations with higher levels of public transport provision but more restricted parking, for later comparison with the results from Longbeutzen and Llanishen. The need for the study was occasioned by the desire to know more about the factors which influence people to share cars, and the characteristics of existing spontaneously formed car-sharing arrangements and participants. To obtain this information, details of the travel and work habits of the workforce concerned had to be collected and analysed. It was considered useful to try to establish any characteristics common to ad-hoc car-sharing participants as a basis for suggesting possible causal factors. The form of the study, in terms of the type of data collected, and its subsequent tabulation, was largely shaped by the need to provide data comparable to that collected in the aforementioned studies at Longbenton and Llanishen. Other work in the Institute on the prediction of demand for car-
sharing (Bonsall, 1980) and the establishment of experimental carsharing schemes (Bonsall et al, 1980) provided a useful basis for comparing the survey requirements for identifying potential car-sharers with those for identifying existing ones
Expert Systems in Transport – Part 1: An Introduction to Expert Systems.
This report describes what expert systems are. It has been written to introduce the concepts involved, and to some extent the techniques, for those who have no previous acquaintance with such systems, but who are concerned with establishing quite what such systems might have to offer, and what is involved in developing them, in their field of application. Ways in which knowledge and uncertainty are represented in expert systems are described, and illustrated by reference to some existing expert systems. The report stems from a project designed to assess the potential for establishing expert systems in the transport field, and discusses the types of expert system package which might be useful in the remaining stages of the project. It includes a useful set of references and a g1ossary.A preliminary assessment of potential transport applications and the implications for the remainder of the project are described in a companion report, ITS Technical Note 145
Specific oligomerization of the 5-HT1A receptor in the plasma membrane
In the present study we analyze the oligomerization of the 5-HT1A receptor within living cells at the sub-cellular level. Using a 2-excitation Förster Resonance Energy Transfer (FRET) method combined with spectral microscopy we are able to estimate the efficiency of energy transfer based on donor quenching as well as acceptor sensitization between CFP-and YFP-tagged 5-HT1A receptors at the plasma membrane. Through the analysis of the level of apparent FRET efficiency over the various relative amounts of donor and acceptor, as well as over a range of total surface expressions of the receptor, we verify the specific interaction of these receptors. Furthermore we study the role of acylation in this interaction through measurements of a palmitoylation-deficient 5-HT1A receptor mutant. Palmitoylation increases the tendency of a receptor to localize in lipid rich microdomains of the plasma membrane. This increases the effective surface density of the receptor and provides for a higher level of stochastic interaction
Horizontal Branch Stars: The Interplay between Observations and Theory, and Insights into the Formation of the Galaxy
We review HB stars in a broad astrophysical context, including both variable
and non-variable stars. A reassessment of the Oosterhoff dichotomy is
presented, which provides unprecedented detail regarding its origin and
systematics. We show that the Oosterhoff dichotomy and the distribution of
globular clusters (GCs) in the HB morphology-metallicity plane both exclude,
with high statistical significance, the possibility that the Galactic halo may
have formed from the accretion of dwarf galaxies resembling present-day Milky
Way satellites such as Fornax, Sagittarius, and the LMC. A rediscussion of the
second-parameter problem is presented. A technique is proposed to estimate the
HB types of extragalactic GCs on the basis of integrated far-UV photometry. The
relationship between the absolute V magnitude of the HB at the RR Lyrae level
and metallicity, as obtained on the basis of trigonometric parallax
measurements for the star RR Lyrae, is also revisited, giving a distance
modulus to the LMC of (m-M)_0 = 18.44+/-0.11. RR Lyrae period change rates are
studied. Finally, the conductive opacities used in evolutionary calculations of
low-mass stars are investigated. [ABRIDGED]Comment: 56 pages, 22 figures. Invited review, to appear in Astrophysics and
Space Scienc
Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET
The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR
On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection
A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)
Relationship of edge localized mode burst times with divertor flux loop signal phase in JET
A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM
The Cholecystectomy As A Day Case (CAAD) Score: A Validated Score of Preoperative Predictors of Successful Day-Case Cholecystectomy Using the CholeS Data Set
Background
Day-case surgery is associated with significant patient and cost benefits. However, only 43% of cholecystectomy patients are discharged home the same day. One hypothesis is day-case cholecystectomy rates, defined as patients discharged the same day as their operation, may be improved by better assessment of patients using standard preoperative variables.
Methods
Data were extracted from a prospectively collected data set of cholecystectomy patients from 166 UK and Irish hospitals (CholeS). Cholecystectomies performed as elective procedures were divided into main (75%) and validation (25%) data sets. Preoperative predictors were identified, and a risk score of failed day case was devised using multivariate logistic regression. Receiver operating curve analysis was used to validate the score in the validation data set.
Results
Of the 7426 elective cholecystectomies performed, 49% of these were discharged home the same day. Same-day discharge following cholecystectomy was less likely with older patients (OR 0.18, 95% CI 0.15–0.23), higher ASA scores (OR 0.19, 95% CI 0.15–0.23), complicated cholelithiasis (OR 0.38, 95% CI 0.31 to 0.48), male gender (OR 0.66, 95% CI 0.58–0.74), previous acute gallstone-related admissions (OR 0.54, 95% CI 0.48–0.60) and preoperative endoscopic intervention (OR 0.40, 95% CI 0.34–0.47). The CAAD score was developed using these variables. When applied to the validation subgroup, a CAAD score of ≤5 was associated with 80.8% successful day-case cholecystectomy compared with 19.2% associated with a CAAD score >5 (p < 0.001).
Conclusions
The CAAD score which utilises data readily available from clinic letters and electronic sources can predict same-day discharges following cholecystectomy
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