153 research outputs found
The Role of Coordinate Systems, Coordinates and Heights in Horizontal Datum Transformations
This paper reviews the fundamental definitions of geodetic and geocentric coordinate systems, whilst clarifying the distinction between coordinates and coordinate systems. It is then argued that the transformation of coordinates from a local geodetic datum to a geocentric datum should first employ a change of the coordinate system using a six- or four-parameter transformation, followed by further modelling of the distortion in the coordinates. It is also argued that the horizontal coordinate transformation should not include height information, since this forms an entirely different coordinate in another coordinate system
Effect of supervised exercise on physical function and balance in patients with intermittent claudication
Background The aim of the study was to identify whether a standard supervised exercise programme (SEP) for patients with intermittent claudication improved specific measures of functional performance including balance. Methods A prospective observational study was performed at a single tertiary vascular centre. Patients with symptomatic intermittent claudication (Rutherford grades 1–3) were recruited to the study. Participants were assessed at baseline (before SEP) and 3, 6 and 12 months afterwards for markers of lower-limb ischaemia (treadmill walking distance and ankle : brachial pressure index), physical function (6-min walk, Timed Up and Go test, and Short Physical Performance Battery (SPPB) score), balance impairment using computerized dynamic posturography with the Sensory Organization Test (SOT), and quality of life (VascuQoL and Short Form 36). Results Fifty-one participants underwent SEP, which significantly improved initial treadmill walking distance (P = 0·001). Enrolment in a SEP also resulted in improvements in physical function as determined by 6-min maximum walking distance (P = 0·006), SPPB score (P < 0·001), and some domains of both generic (bodily pain, P = 0·025) and disease-specific (social domain, P = 0·039) quality of life. Significant improvements were also noted in balance, as determined by the SOT (P < 0·001). Conclusion Supervised exercise improves both physical function and balance impairment
The rigorous determination of orthometric heights
The main problem of the rigorous definition of the orthometric height is the evaluation of the mean value of the Earth’s gravity acceleration along the plumbline within the topography. To find the exact relation between rigorous orthometric and Molodensky’s normal heights, the mean gravity is decomposed into: the mean normal gravity, the mean values of gravity generated by topographical and atmospheric masses, and the mean gravity disturbance generated by the masses contained within geoid. The mean normal gravity is evaluated according to Somigliana–Pizzetti’s theory of the normal gravity field generated by the ellipsoid of revolution. Using the Bruns formula, the mean values of gravity along the plumbline generated by topographical and atmospheric masses can be computed as the integral mean between the Earth’s surface and geoid. Since the disturbing gravity potential generated by masses inside the geoid is harmonic above the geoid, the mean value of the gravity disturbance generated by the geoid is defined by applying the Poisson integral equation to the integral mean. Numerical results for a test area in the Canadian Rocky Mountains show that the difference between the rigorously defined orthometric height and the Molodensky normal height reaches 0.5 m
New views of the spherical Bouguer gravity anomaly
This paper presents a number of new concepts concerning the gravity anomaly. First, it identifies a distinct difference between a surface (2-D) gravity anomaly (the difference between actual gravity on one surface and normal gravity on another surface) and a solid (3-D) gravity anomaly defined in the fundamental gravimetric equation. Second, it introduces the 'no topography' gravity anomaly (which turns out to be the complete spherical Bouguer anomaly) as a means to generate a quantity that is smooth, thus suitable for gridding, and harmonic, thus suitable for downward continuation. It is understood that the possibility of downward continuing a smooth gravity anomaly would simplify the task of computing an accurate geoid. It is also shown that the planar Bouguer anomaly is not harmonic, and thus cannot be downward continued
Survey for Transiting Extrasolar Planets in Stellar Systems IV: Variables in the Field of NGC 1245
The Survey for Transiting Extrasolar Planets in Stellar Systems (STEPSS)
project is a search for planetary transits in open clusters. In this paper, we
analyze the STEPSS observations of the open cluster NGC 1245 to determine the
variable star content of the cluster. Out of 6787 stars observed with V < 22,
of which ~870 are cluster members, we find 14 stars with clear intrinsic
variability that are potential cluster members, and 29 clear variables that are
not cluster members. None of these variables have been previously identified.
We present light curves, finding charts, and stellar/photometric data on these
variable objects. Several of the interacting binaries have estimated distances
consistent with the cluster distance determined from isochrone fits to the
color magnitude diagram. Four stars at the main sequence turnoff of the cluster
have light curves consistent with gamma Doradus variability. If these gamma
Doradus candidates are confirmed, they represent the oldest and coolest members
of this class of variable discovered to date.Comment: 20 pages, 15 figures. Submitted to AJ. PDF version with
full-resolution figures at http://www.astronomy.ohio-state.edu/~pepper/ms.pd
Forming norms: informing diagnosis and management in sports medicine
Clinicians aim to identify abnormalities, and distinguish harmful from harmless abnormalities. In sports medicine, measures of physical function such as strength, balance and joint flexibility are used as diagnostic tools to identify causes of pain and disability and monitor progression in response to an intervention. Comparing results from clinical measures against ‘normal’ values guides decision-making regarding health outcomes. Understanding ‘normal’ is therefore central to appropriate management of disease and disability. However, ‘normal’ is difficult to clarify and definitions are dependent on context. ‘Normal’ in the clinical setting is best understood as an appropriate state of physical function. Particularly as disease, pain and sickness are expected occurrences of being human, understanding ‘normal’ at each stage of the lifespan is essential to avoid the medicalisation of usual life processes. Clinicians use physical measures to assess physical function and identify disability. Accurate diagnosis hinges on access to ‘normal’ reference values for such measures. However our knowledge of ‘normal’ for many clinical measures in sports medicine is limited. Improved knowledge of normal physical function across the lifespan will assist greatly in the diagnosis and management of pain, disease and disability
Proceedings of the 1st WSEAS International Conference on "Environmental and Geological Science and Engineering (EG'08)"
This book contains the proceedings of the 1st WSEAS International Conference on Environmental and Geological Science and Engineering (EG'08) which was held in Malta, September 11-13, 2008. This conference aims to disseminate the latest research and applications in Renewable Energy, Mineral Resources, Natural Hazards and Risks,
Environmental Impact Assessment, Urban and Regional Planning Issues, Remote Sensing and
GIS, and other relevant topics and applications.
The friendliness and openness of the WSEAS conferences, adds to their ability to grow by
constantly attracting young researchers. The WSEAS Conferences attract a large number of well-established and leading researchers in various areas of Science and Engineering as you can see from http://www.wseas.org/reports. Your feedback encourages the society to go ahead as you
can see in http://www.worldses.org/feedback.htm
The contents of this Book are also published in the CD-ROM Proceedings of the Conference.
Both will be sent to the WSEAS collaborating indices after the conference:
www.worldses.org/indexes
In addition, papers of this book are permanently available to all the scientific community via the WSEAS E-Library.
Expanded and enhanced versions of papers published in this conference proceedings are also going to be considered for possible publication in one of the WSEAS journals that participate in the major International Scientific Indices (Elsevier, Scopus, EI, ACM, Compendex, INSPEC, CSA .... see: www.worldses.org/indexes) these papers must be of high-quality (break-through work) and a new round of a very strict review will follow. (No additional fee will be required for the publication of the extended version in a journal). WSEAS has also collaboration with several other international publishers and all these excellent papers of this volume could be further improved, could be extended and could be enhanced for possible additional evaluation in one of the editions of these international publishers. Finally, we cordially thank all the people of WSEAS for their efforts to maintain the high scientific level of conferences, proceedings and journals
Unexpected features of branched flow through high-mobility two-dimensional electron gases
GaAs-based two-dimensional electron gases (2DEGs) show a wealth of remarkable
electronic states, and serve as the basis for fast transistors, research on
electrons in nanostructures, and prototypes of quantum-computing schemes. All
these uses depend on the extremely low levels of disorder in GaAs 2DEGs, with
low-temperature mean free paths ranging from microns to hundreds of microns.
Here we study how disorder affects the spatial structure of electron transport
by imaging electron flow in three different GaAs/AlGaAs 2DEGs, whose mobilities
range over an order of magnitude. As expected, electrons flow along narrow
branches that we find remain straight over a distance roughly proportional to
the mean free path. We also observe two unanticipated phenomena in
high-mobility samples. In our highest-mobility sample we observe an almost
complete absence of sharp impurity or defect scattering, indicated by the
complete suppression of quantum coherent interference fringes. Also, branched
flow through the chaotic potential of a high-mobility sample remains stable to
significant changes to the initial conditions of injected electrons.Comment: 22 pages, 4 figures, 1 tabl
The double-mode nature of the HADS star GSC 00144-03031 and the Petersen diagram of the class
The double--mode pulsation of GSC 00144-03031 has been detected when
searching for COROT targets. A very large dataset composed of 4722 photometric
measurements was collected at six observatories in Europe and America. There is
no hint of the excitation of additional modes (down to 0.6 mmag) and therefore
GSC 00144-03031 seems to be a pure double--mode pulsator, with a very short
fundamental radial mode (P=84 min). From Stromgren photometry and evolutionary
tracks it appears to be a Pop. I star with M=1.75 solar masses, located in the
middle of the instability strip, close to the Zero--Age Main Sequence. We also
discovered other new double--mode pulsators in the databases of large--scale
projects: OGLE BW2_V142, OGLE BW1_V207, ASAS3 094303-1707.3, ASAS3
000116-6037.0, NSVS 3234596 and NSVS 3324715. An observational Petersen diagram
is presented and explained by means of new models. A common sequence connecting
Pop. I stars from the shortest to the longest periods is proposed and the
spreads in the period ratios are ascribed to different metallicities (at the
shortest periods) and to different masses (at the longest ones). The paper is
based on data collected at S. Pedro Martir and Sierra Nevada Observatories and
on the contributions from several amateur astronomers.Comment: 9 pages, 5 pages, accepted for publication in Astronomy and
Astrophysic
- …