6,513 research outputs found
Model-independent constraints on contact interactions from LEP2 data analysis
We derive model-independent constraints on four-fermion contact
interaction-type dynamics from the published preliminary LEP2 experimental data
on e^+e^- annihilation into \mu^+\mu^- and \tau^+\tau^- pairs, measured at
different energies between 130 and 207 GeV. The basic observables are chosen to
be the total cross section and the forward-backward asymmetry, and the analysis
realistically takes into account data uncertainties and correlations among
measurements at the various energies. The combination of data from different
energy points plays an important role in the determination of regions allowed
for the contact interaction coupling constants. In contrast to the more common
one-parameter analyses, we only obtain constraints on pairs of parameters
rather than limits on individual ones.Comment: 13 pages, LaTeX, including figures. v2: Included discussion of tau
data, version to appear in EPJ
The Estimation of the Effective Centre of Mass Energy in q-qbar-gamma Events from DELPHI
The photon radiation in the initial state lowers the energy available for the
ee collisions; this effect is particularly important at LEP2 energies
(above the mass of the Z boson). Being aligned to the beam direction, such
initial state radiation is mostly undetected. This article describes the
procedure used by the DELPHI experiment at LEP to estimate the effective
centre-of-mass energy in hadronic events collected at energies above the Z
peak. Typical resolutions ranging from 2 to 3 GeV on the effective
center-of-mass energy are achieved, depending on the event topology.Comment: 12 pages, 6 figure
Physical Activity, Obesity, Family History, and their Associations with Hypertension among The Elderly in Aceh Singkil, Aceh
Background: Hypertension is an important global health challenge due to its high prevalence and resulting cardiovascular disease and chronic kidney disease. This study aimed to examine the associations of physical activity, obesity, family history, with hypertension among the elderly in Aceh Singkil, Aceh.
Subjects and Method: This was a case control study carried out in Aceh Singkil, Aceh. A sample of 132 elderly was selected for this study, consisting 66 elderly with hypertension and 66 elderly without hypertension. The dependent variable was hypertension. The independent variables were physical activity, obesity, and family history. Hypertension data was measured by sphygmomanometer. The other data were collected by questionnaire. The data were analyzed by a multiple logistic regression model.
Results: Hypertension was associated with physical inactivity (OR= 5.12; 95% CI= 2.41 to 10.86; p<0.001), obesity (OR= 3.30; 95% CI= 1.61 to 6.74; p<0.001), and family history (OR= 7.73; 95% CI= 3.56 to 16.78; p<0.001).
Conclusion: Physical inactivity, obesity, and family history, are associated with an increased risk of hypertension.
Keywords: physical activity, obesity, family history, hypertensio
The integrability of Lie-invariant geometric objects generated by ideals in the Grassmann algebra
We investigate closed ideals in the Grassmann algebra serving as bases of
Lie-invariant geometric objects studied before by E. Cartan. Especially, the E.
Cartan theory is enlarged for Lax integrable nonlinear dynamical systems to be
treated in the frame work of the Wahlquist Estabrook prolongation structures on
jet-manifolds and Cartan-Ehresmann connection theory on fibered spaces. General
structure of integrable one-forms augmenting the two-forms associated with a
closed ideal in the Grassmann algebra is studied in great detail. An effective
Maurer-Cartan one-forms construction is suggested that is very useful for
applications. As an example of application the developed Lie-invariant
geometric object theory for the Burgers nonlinear dynamical system is
considered having given rise to finding an explicit form of the associated Lax
type representation
Evaluation Techniques and Systems for Answer Set Programming: a Survey
Answer set programming (ASP) is a prominent knowledge representation and reasoning paradigm that found both industrial and scientific applications. The success of ASP is due to the combination of two factors: a rich modeling language and the availability of efficient ASP implementations. In this paper we trace the history of ASP systems, describing the key evaluation techniques and their implementation in actual tools
Lie group analysis of a generalized Krichever-Novikov differential-difference equation
The symmetry algebra of the differential--difference equation
where , and are arbitrary analytic functions is shown to have the
dimension 1 \le \mbox{dim}L \le 5. When , and are specific second
order polynomials in (depending on 6 constants) this is the integrable
discretization of the Krichever--Novikov equation. We find 3 cases when the
arbitrary functions are not polynomials and the symmetry algebra satisfies
\mbox{dim}L=2. These cases are shown not to be integrable. The symmetry
algebras are used to reduce the equations to purely difference ones. The
symmetry group is also used to impose periodicity and thus to
reduce the differential--difference equation to a system of coupled
ordinary three points difference equations
The methodology of investigation on red- and black-figured pottery of unknown provenance
This contribution is concerned with the archaeometric study of seven red- and black-figured potteries, kindly provided by the Carabinieri Corps for Protection of Cultural Heritage, Cosenza Unit (Calabria, Italy). The study was aimed to establish the authenticity of the archaeological artifacts and for this purpose an analytical approach, based on mineropetrographic and geochemical investigations, was applied. Petrographic analysis (OM), scanning electron microscopy (SEM) coupled with EDS microanalysis and X-ray diffraction (XRD) studies were carried out with the aim of identifying technological features, microstructure and to obtain information on the technological features of each sample. Finally, Fourier transform infrared spectroscopy (FT-IR) was used to detect possible surface coatings
Stability of the selfsimilar dynamics of a vortex filament
In this paper we continue our investigation about selfsimilar solutions of
the vortex filament equation, also known as the binormal flow (BF) or the
localized induction equation (LIE). Our main result is the stability of the
selfsimilar dynamics of small pertubations of a given selfsimilar solution. The
proof relies on finding precise asymptotics in space and time for the tangent
and the normal vectors of the perturbations. A main ingredient in the proof is
the control of the evolution of weighted norms for a cubic 1-D Schr\"odinger
equation, connected to the binormal flow by Hasimoto's transform.Comment: revised version, 36 page
Is baryon number violated when electroweak strings intercommute?
We reexamine the self-helicity and the intercommutation of electroweak
strings. A plausible argument for baryon number conservation when electroweak
strings intercommute is presented. The connection between a segment of
electroweak strings and a sphaleron is also discussed.Comment: CALT-68-1948, 11 pages, 5 figures available upon request. Replaced
with revised version. (Request should be sent to [email protected]
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