1,989 research outputs found
Automated mixed traffic vehicle control and scheduling study
The operation and the expected performance of a proposed automatic guideway transit system which uses low speed automated mixed traffic vehicles (AMTVs) were analyzed. Vehicle scheduling and headway control policies were evaluated with a transit system simulation model. The effect of mixed traffic interference on the average vehicle speed was examined with a vehicle pedestrian interface model. Control parameters regulating vehicle speed were evaluated for safe stopping and passenger comfort. Some preliminary data on the cost and operation of an experimental AMTV system are included. These data were the result of a separate task conducted at JPL, and were included as background information
Lensed CMB power spectra from all-sky correlation functions
Weak lensing of the CMB changes the unlensed temperature anisotropy and
polarization power spectra. Accounting for the lensing effect will be crucial
to obtain accurate parameter constraints from sensitive CMB observations.
Methods for computing the lensed power spectra using a low-order perturbative
expansion are not good enough for percent-level accuracy. Non-perturbative
flat-sky methods are more accurate, but curvature effects change the spectra at
the 0.3-1% level. We describe a new, accurate and fast, full-sky
correlation-function method for computing the lensing effect on CMB power
spectra to better than 0.1% at l<2500 (within the approximation that the
lensing potential is linear and Gaussian). We also discuss the effect of
non-linear evolution of the gravitational potential on the lensed power
spectra. Our fast numerical code is publicly available.Comment: 16 pages, 4 figures. Changes to match PRD version including new
section on non-linear corrections. CAMB code available at http://camb.info
Delayed degradation of chlorophylls and photosynthetic proteins in Arabidopsis autophagy mutants during stress-induced leaf yellowing
Under mild abiotic-stress conditions, Arabidopsis atg mutants showed a functional stay-green phenotype which is probably caused by the lack of chloroplastic autophagy and the retrograde regulation of senescence-associated gene expressio
Improved radiative corrections for (e,e'p) experiments: Beyond the peaking approximation and implications of the soft-photon approximation
Analysing (e,e'p) experimental data involves corrections for radiative
effects which change the interaction kinematics and which have to be carefully
considered in order to obtain the desired accuracy. Missing momentum and energy
due to bremsstrahlung have so far always been calculated using the peaking
approximation which assumes that all bremsstrahlung is emitted in the direction
of the radiating particle. In this article we introduce a full angular Monte
Carlo simulation method which overcomes this approximation. The angular
distribution of the bremsstrahlung photons is reconstructed from H(e,e'p) data.
Its width is found to be underestimated by the peaking approximation and
described much better by the approach developed in this work.Comment: 11 pages, 13 figure
Coupling of alpha(1)-Adrenoceptors to ERK1/2 in the Human Prostate
Introduction: alpha(1)-Adrenoceptors are considered critical for the regulation of prostatic smooth muscle tone. However, previous studies suggested further alpha(1)-adrenoceptor functions besides contraction. Here, we investigated whether alpha(1)-adrenoceptors in the human prostate may activate extracellular signal-regulated kinases (ERK1/2). Methods: Prostate tissues from patients undergoing radical prostatectomy were stimulated in vitro. Activation of ERK1/2 was assessed by Western blot analysis. Expression of ERK1/2 was studied by immunohistochemistry. The effect of ERK1/2 inhibition by U0126 on phenylephrine-induced contraction was studied in organ-bath experiments. Results: Stimulation of human prostate tissue with noradrenaline (30 mu M) or phenylephrine (10 mu M) resulted in ERK activation. This was reflected by increased levels of phosphorylated ERK1/2. Expression of ERK1/2 in the prostate was observed in smooth muscle cells. Incubation of prostate tissue with U0126 (30 mu M) resulted in ERK1/2 inhibition. Dose-dependent phenylephrine-induced contraction of prostate tissue was not modulated by U0126. Conclusions: alpha(1)-Adrenoceptors in the human prostate are coupled to ERK1/2. This may partially explain previous observations suggesting a role of alpha(1)-adrenoceptors in the regulation of prostate growth. Copyright (C) 2011 S. Karger AG, Base
Rhythmic dynamics and synchronization via dimensionality reduction : application to human gait
Reliable characterization of locomotor dynamics of human walking is vital to understanding the neuromuscular control of human locomotion and disease diagnosis. However, the inherent oscillation and ubiquity of noise in such non-strictly periodic signals pose great challenges to current methodologies. To this end, we exploit the state-of-the-art technology in pattern recognition and, specifically, dimensionality reduction techniques, and propose to reconstruct and characterize the dynamics accurately on the cycle scale of the signal. This is achieved by deriving a low-dimensional representation of the cycles through global optimization, which effectively preserves the topology of the cycles that are embedded in a high-dimensional Euclidian space. Our approach demonstrates a clear advantage in capturing the intrinsic dynamics and probing the subtle synchronization patterns from uni/bivariate oscillatory signals over traditional methods. Application to human gait data for healthy subjects and diabetics reveals a significant difference in the dynamics of ankle movements and ankle-knee coordination, but not in knee movements. These results indicate that the impaired sensory feedback from the feet due to diabetes does not influence the knee movement in general, and that normal human walking is not critically dependent on the feedback from the peripheral nervous system
The OPERA experiment Target Tracker
The main task of the Target Tracker detector of the long baseline neutrino
oscillation OPERA experiment is to locate in which of the target elementary
constituents, the lead/emulsion bricks, the neutrino interactions have occurred
and also to give calorimetric information about each event. The technology used
consists in walls of two planes of plastic scintillator strips, one per
transverse direction. Wavelength shifting fibres collect the light signal
emitted by the scintillator strips and guide it to both ends where it is read
by multi-anode photomultiplier tubes. All the elements used in the construction
of this detector and its main characteristics are described.Comment: 25 pages, submitted to Nuclear Instrument and Method
On the Self-Similar Appearance of Galaxy Clusters in X-rays
The largest uncertainty for cosmological studies using clusters of galaxies
is introduced by our limited knowledge of the statistics of galaxy cluster
structure, and of the scaling relations between observables and cluster mass. A
large effort is therefore undertaken to compile global galaxy cluster
properties in particular obtained through X-ray observations and to study their
scaling relations. However, the scaling schemes used in the literature differ.
The present paper aims to clarify this situation by providing a thorough review
of the scaling laws within the standard model of large-scale structure growth
and to discus various steps of practical approximations. We derive the scaling
laws for X-ray observables and cluster mass within the pure gravitational
structure growth scenario. Using N-body simulations we test the recent
formation approximation used in earlier analytic approaches which involves a
redshift dependent overdensity parameter.We find this approximation less
precise than the use of a fiducial radius based on a fixed overdensity with
respect to critical density. Inspired by the comparison of the predicted
scaling relations with observations we propose a first order modification of
the scaling scheme to include the observed effects of hydrodynamics in
structure formation. This modification involves a cluster mass dependent gas
mass fraction. We also discuss the observational results of the reshift
evolution of the most important scaling relations and find that also a redshift
dependence of the gas mass to total mass relation has to be invoked within our
modification scheme. We find that the current observational data are within
their uncertainties consistent with the proposed modified scaling laws.Comment: Astronomy and Astrophysics (in press) 14 pages, 6 figure
Let’s makan!: Savoring Singapore’s culinary heritage in hotel restaurants
Eating is a national pastime in Singapore and food features strongly in many aspects of the city-state’s social and cultural landscape. Culinaria and gastronomy can be significant features of a destination and they allow tourists to experience local cultures, heritage and lifestyles. Street (hawker) food in Singapore offers a unique opportunity for visitors to sample popular local dishes conveniently and economically, whilst experiencing a vibrant taste of the colloquial way of life through eating and socializing with the locals. Many hotels in Singapore also commonly feature local signature dishes in their menu and foodservice outlets. This study aims to explore the role of street (hawker) food and local cuisine as a tourism and cultural resource within the Asian hospitality context. It investigates the phenomenon of Asian street food and traditional cuisines served in international chain hotels, specifically from a hotel and destination branding perspective, with a particular example of Singapore as a tourist destination. Keywords: Street Food, Asian Cuisine, Hotel Restaurants, Food Heritage, Brand Identit
Comparison of Image Registration Based Measures of Regional Lung Ventilation from Dynamic Spiral CT with Xe-CT
Purpose: Regional lung volume change as a function of lung inflation serves
as an index of parenchymal and airway status as well as an index of regional
ventilation and can be used to detect pathologic changes over time. In this
article, we propose a new regional measure of lung mechanics --- the specific
air volume change by corrected Jacobian.
Methods: 4DCT and Xe-CT data sets from four adult sheep are used in this
study. Nonlinear, 3D image registration is applied to register an image
acquired near end inspiration to an image acquired near end expiration.
Approximately 200 annotated anatomical points are used as landmarks to evaluate
registration accuracy. Three different registration-based measures of regional
lung mechanics are derived and compared: the specific air volume change
calculated from the Jacobian (SAJ); the specific air volume change calculated
by the corrected Jacobian (SACJ); and the specific air volume change by
intensity change (SAI).
Results: After registration, the mean registration error is on the order of 1
mm. For cubical ROIs in cubes with size 20 mm 20 mm 20 mm,
the SAJ and SACJ measures show significantly higher correlation (linear
regression, average and ) with the Xe-CT based measure of
specific ventilation (sV) than the SAI measure. For ROIs in slabs along the
ventral-dorsal vertical direction with size of 150 mm 8 mm 40
mm, the SAJ, SACJ, and SAI all show high correlation (linear regression,
average , and ) with the Xe-CT based sV without
significant differences when comparing between the three methods.
Conclusion: Given a deformation field by an image registration algorithm,
significant differences between the SAJ, SACJ, and SAI measures were found at a
regional level compared to the Xe-CT sV in four sheep that were studied
- …
