8,199 research outputs found
Interferometry versus projective measurement of anyons
The distinct methods for measuring topological charge in a non-abelian
anyonic system have been discussed in the literature: projective measurement of
a single point-like quasiparticle and interferometric measurement of the total
topological charge of a group of quasiparticles. Projective measurement by
definition is only applied near a point and will project to a topological
charge sector near that point. Thus, if it is to be applied to a \emph{group}
of anyons to project to a \emph{total} charge, then the anyons must first be
fused one by one to obtain a single anyon carrying the collective charge. We
show that interferometric measurement is strictly stronger: Any protocol
involving projective measurement can be simulated at low overhead by another
protocol involving only interferometric measurement.Comment: 6 pages, 7 figure
A first-order time-domain Green's function approach to supersonic unsteady flow
A time-domain Green's Function Method for unsteady supersonic potential flow around complex aircraft configurations is presented. The focus is on the supersonic range wherein the linear potential flow assumption is valid. The Green's function method is employed in order to convert the potential-flow differential equation into an integral one. This integral equation is then discretized, in space through standard finite-element technique, and in time through finite-difference, to yield a linear algebraic system of equations relating the unknown potential to its prescribed co-normalwash (boundary condition) on the surface of the aircraft. The arbitrary complex aircraft configuration is discretized into hyperboloidal (twisted quadrilateral) panels. The potential and co-normalwash are assumed to vary linearly within each panel. Consistent with the spatial linear (first-order) finite-element approximations, the potential and co-normalwash are assumed to vary linearly in time. The long range goal of our research is to develop a comprehensive theory for unsteady supersonic potential aerodynamics which is capable of yielding accurate results even in the low supersonic (i.e., high transonic) range
Systems aspects of COBE science data compression
A general approach to compression of diverse data from large scientific projects has been developed and this paper addresses the appropriate system and scientific constraints together with the algorithm development and test strategy. This framework has been implemented for the COsmic Background Explorer spacecraft (COBE) by retrofitting the existing VAS-based data management system with high-performance compression software permitting random access to the data. Algorithms which incorporate scientific knowledge and consume relatively few system resources are preferred over ad hoc methods. COBE exceeded its planned storage by a large and growing factor and the retrieval of data significantly affects the processing, delaying the availability of data for scientific usage and software test. Embedded compression software is planned to make the project tractable by reducing the data storage volume to an acceptable level during normal processing
A first-order Green's function approach to supersonic oscillatory flow: A mixed analytic and numeric treatment
A frequency domain Green's Function Method for unsteady supersonic potential flow around complex aircraft configurations is presented. The focus is on the supersonic range wherein the linear potential flow assumption is valid. In this range the effects of the nonlinear terms in the unsteady supersonic compressible velocity potential equation are negligible and therefore these terms will be omitted. The Green's function method is employed in order to convert the potential flow differential equation into an integral one. This integral equation is then discretized, through standard finite element technique, to yield a linear algebraic system of equations relating the unknown potential to its prescribed co-normalwash (boundary condition) on the surface of the aircraft. The arbitrary complex aircraft configuration (e.g., finite-thickness wing, wing-body-tail) is discretized into hyperboloidal (twisted quadrilateral) panels. The potential and co-normalwash are assumed to vary linearly within each panel. The long range goal is to develop a comprehensive theory for unsteady supersonic potential aerodynamic which is capable of yielding accurate results even in the low supersonic (i.e., high transonic) range
The use of blocking software or Internet filters in southern New Jersey public libraries
The purpose of this study was to determine if public libraries in southern New Jersey have installed blocking software or filters on their Internet computers and, specifically, to find out what types of filters or blocking software they were currently using in their libraries. The study wanted to see how satisfied librarians were with their filters or blocking software. The study also looked at whether or not public libraries in southern New Jersey have written Acceptable Use Policies which define access to the Internet for some or all of their patrons, including children under the age of eighteen. Finally, the study examined whether or not public librarians were aware of Federal regulations including the Children\u27s Internet Protection Act. This applied research design employed mailed questionnaires to collect data from 67 public libraries in southern New Jersey. Analysis of the data revealed that many smaller public libraries have not installed filters or blocking software on their Internet computers. Approximately half the libraries surveyed were utilizing filters or blocking software on their Internet computers for either adults or children under the age of eighteen
Probing new physics with coherent neutrino scattering off nuclei
The possibility off measuring for the first time neutrino-nuclei coherent
scattering has been recently discussed by several experimental collaborations.
It is shown that such a measurement may be very sensitive to non-standard
interactions of neutrinos with quarks and might set better constraints than
those coming from future neutrino factory experiments. We also comment on other
types of new physics tests, such as extra heavy neutral gauge bosons, where the
sensitivity to some models is slightly better than the Tevatron constraint and,
therefore, could give complementary bounds.Comment: 15 pages, 4 figures Discussion about Z prime corrected and extended.
Final version to be published in JHE
Study of 50 cases of carcinoma of the lung: from the point of view of early diagnosis
Fifty cases of primary carcinoma of the lung have
been described and it has been found that:1. Carcinoma of the lung occurred practically
always in people over 40.2. It was 7 times as common in males as in
females.3. In 22 per cent of cases it occurred in people
who had had a cough for a number of years.4. Pleural effusion appeared in 12 per cent of
the cases.5. Clubbing of the fingers occurred in 22 per cent
of the cases and it appears probable that
carcinoma of the lung alone can cause it.6. The symptoms of greatest importance for diagnosis
were cough, haemoptysis, dyspnoea, pain in the
chest and loss of weight. They occurred
fairly early in most of the cases.7. The physical signs of greatest importance for
diagnosis were those suggesting collapse of
lung tissue, by the time these were present
the disease was too advanced for surgery to be
successful.8. Examination of the sputum for carcinoma cells
was a very valuable aid in diagnosis and it
deserves to be used more than it is at present.9. The radiographical appearance of collapse of
lung tissue is very suggestive of carcinoma
of the lung Eby the time this was apparent in
the radiograms the disease was too advanced
for surgery to be successful.10. Bronchoscopy was the most valuable method of
diagnosis. It revealed the exact site of the
growth which is important when the possibility
of pneumonectomy is being considered. It also
furnished conclusive proof of the nature of the
growth. It should be done at the earliest
possible moment whenever the symptoms are at all
suspicious of carcinoma of the lung. If this
is done there is hope that we will be able to
diagnose the condition at an early stage more
frequently. It is the duty of all medical
practitioners to send cases at the earliest
possible moment.11. The Sedimentation rate was considerably raised
in every case except one in which it was
estimated but it is not of great value in
diagnosis because of the large number of diseases
which can cause a raised blood sedimentation rate.12. None of the cases in this series was cured. The
only hope of cure at present lies in early
diagnosis. We can only hope to diagnose the
minority of cases early enough for surgery to be
successful. One of the difficulties is that
patients often ignore symptoms for a long time
before seeking medical advice and this can only
be partly overcome by warning the public of the
danger of neglecting them. A certain number
of cases do come to us soon after the development of symptoms and we must be prepared to
call in the aid of the radiologist, pathologist
and bronchoscopist when we hear suspicious
symptoms in spite of the fact that there are
no abnormal physical signs. Every patient over the age of 40
with a cough which does not improve with
treatment after a week or so should be subjected to the routine accessory methods of
diagnosis. If this is done we would
discover more cases at a stage in which surgery
would be successful
The Hidden Spatial Geometry of Non-Abelian Gauge Theories
The Gauss law constraint in the Hamiltonian form of the gauge theory
of gluons is satisfied by any functional of the gauge invariant tensor variable
. Arguments are given that the tensor is a more appropriate variable. When the Hamiltonian
is expressed in terms of or , the quantity appears.
The gauge field Bianchi and Ricci identities yield a set of partial
differential equations for in terms of . One can show that
is a metric-compatible connection for with torsion, and that the curvature
tensor of is that of an Einstein space. A curious 3-dimensional
spatial geometry thus underlies the gauge-invariant configuration space of the
theory, although the Hamiltonian is not invariant under spatial coordinate
transformations. Spatial derivative terms in the energy density are singular
when . These singularities are the analogue of the centrifugal
barrier of quantum mechanics, and physical wave-functionals are forced to
vanish in a certain manner near . It is argued that such barriers are
an inevitable result of the projection on the gauge-invariant subspace of the
Hilbert space, and that the barriers are a conspicuous way in which non-abelian
gauge theories differ from scalar field theories.Comment: 19 pages, TeX, CTP #223
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