1,511 research outputs found
Precision Determination of the Top Quark Mass
The CDF and D0 collaborations have updated their measurements of the mass of
the top quark using proton-antiproton collisions at sqrt{s}=1.96TeV produced at
the Tevatron. The uncertainties in each of the of top-antitop decay channels
have been reduced. The new Tevatron average for the mass of the top quark based
on about 1/fb of data per experiment is 170.9+-1.8GeV/c^2.Comment: 14 pages, 4 figures; LaTeX2e, 8 .eps files, uses LaThuileFPSpro.sty
(included). To appear in the proceedings of the 21st Rencontres des Physique
de la Vallee d'Aoste, La Thuile, March 4-10, 200
Performance of the CDF Calorimeter Simulation in Tevatron Run II
The CDF experiment is successfully collecting data from ppbar collisions at
the Tevatron in Run II. As the data samples are getting larger, systematic
uncertainties due to the measurement of the jet energy scale assessed using the
calorimeter simulation have become increasingly important. In many years of
operation, the collaboration has gained experience with GFLASH, a fast
parametrization of electromagnetic and hadronic showers used for the
calorimeter simulation. We present the performance of the calorimeter
simulation and report on recent improvements based on a refined in situ tuning
technique. The central calorimeter response is reproduced with a precision of
1-2%.Comment: 8 pages, 4 figures; LaTeX2e, 10 .eps files, uses aipproc.cls,
aipxfm.sty and aip-6s.clo (included). Contribution to the Proceedings of the
12th International Conference on Calorimetry in High Energy Physics
(CALOR06), June 5-9, 2006, Chicago (IL), USA. To be published by American
Institute of Physics (AIP
Tests of Power Corrections to Event Shape Distributions from e+e- Annihilation
A study of differential event shape distributions using e+e- data at
centre-of-mass energies of 35 to 183 GeV is presented. We investigated
non-perturbative power corrections for the thrust, C-parameter, total and wide
jet broadening observables. We observe a good description of the distributions
by the combined resummed QCD calculations plus power corrections from the
dispersive approach. The single non-perturbative parameter \alpha_0 is measured
to be \alpha_0 (2 GeV) = 0.502 +- 0.013 (stat.) ^{+0.046)_{-0.032} (exp. syst.)
^{+0.074}_{-0.053} (theo. syst.) and is found to be universal for the
observables studied within the given systematic uncertainties. Using revised
calculations of the power corrections for the jet broadening variables,
improved consistency of the individual fit results is obtained. Agreement is
also found with results extracted from the mean values of event shape
distributions.Comment: 19 pages, LaTeX2e, 8 .eps-files included, paper contributed to the
EPS-HEP99 conference in Tampere, Finlan
Tests of Power Corrections for Event Shapes in e+e- Annihilation
A study of perturbative QCD calculations combined with power corrections to
model hadronisation effects is presented. The QCD predictions are fitted to
differential distributions and mean values of event shape observables measured
in e+e- annihilation at centre-of-mass energies from 14 to 189 GeV. We
investigate the event shape observables thrust, heavy jet mass, C-parameter,
total and wide jet broadening and differential 2-jet rate and observe a good
description of the data by the QCD predictions. The strong coupling constant
alpha_S(M_Z) and the free parameter of the power correction calculations
alpha_0(2 GeV) are measured to be alpha_S(M_Z) = 0.1171 +/- 0.0032/0.0020 and
alpha_0(2 GeV) = 0.513 +/- 0.066/0.045. The predicted universality of alpha_0
is confirmed within the uncertainties of the measurements.Comment: 28 pages, LaTeX2e, 21 .eps-files included, accepted by Eur. Phys. J.
El razonamiento proporcional. Un estudio comparativo realizado dentro y fuera de la escuela
Este trabajo muestra un estudio comparativo de la forma como razonan proporcionalmente dos poblaciones de trabajo, la primera, estudiantes escolarizados (Escuela Básica de IngenierĂa) y la segunda, personas no escolarizadas (Campesinos de la Sierra Nevada de Santa Marta). Para ello se formulan situaciones problemáticas en contexto que involucran proporcionalidades entre magnitudes, inmersas en las categorĂas de producto de medida e isomorfismo de medid
When risk becomes illness: The personal and social consequences of cervical intraepithelial neoplasia medical surveillance
[Abstract]
Background,
After the early detection of cervical intraepithelial neoplasia (CIN), medical surveillance of
the precancerous lesions is carried out to control risk factors to avoid the development of
cervical cancer.
Objective.
To explore the effects of medical surveillance on the personal and social lives of women
undergoing CIN follow-up and treatment.
Methodology.
A generic qualitative study using a poststructuralist perspective of risk management was
carried out in a gynecology clinic in a public hospital of the Galician Health Care System
(Spain). Participants were selected through purposive sampling. The sample consisted of
21 women with a confirmed diagnosis of CIN. Semistructured interviews were recorded and
transcribed, and a thematic analysis was carried out, including researcher triangulation to
verify the results of the analysis.
Findings.
Two main themes emerged from the participants’ experiences: CIN medical surveillance
encounters and risk management strategies are shaped by the biomedical discourse, and
the effects of “risk treatment” for patients include (a) profound changes expected of patients,
(b) increased patient risk management, and (c) resistance to risk management. While doctors’ surveillance aimed to prevent the development of cervical cancer, women felt they
were sick because they had to follow strict recommendations over an unspecified period of
time and live with the possibility of a life-threatening disease. Clinical risk management resulted in the medicalization of women’s personal and social lives and produced great
uncertainty.
Conclusions.
This study is the first to conceptualize CIN medical surveillance as an illness experience for
patients. It also problematizes the effects of preventative practices in women’s lives.
Patients deal with great uncertainty, as CIN medical surveillance performed by gynecologists simultaneously trivializes the changes expected of patients and underestimates the
effects of medical recommendations on patients’ personal wellbeing and social relations
C-Parameter and Jet Broadening at PETRA Energies
e^+e^- annihilation data recorded by the JADE detector at PETRA were used to
measure the C-parameter for the first time at \sqrt{s}= 35 and 44 GeV. The
distributions were compared to a resummed QCD calculation.
In addition, we applied extended resummed calculations to the total and wide
jet broadening variables, B_T and B_W. We combined the results on \alpha_s with
those of our previous study of differential 2-jet rate, thrust, and heavy jet
mass, obtaining
\alpha_s(35 GeV) = 0.1448 +0.0117 -0.0070 and \alpha_s(44 GeV) = 0.1392
+0.0105 -0.0074.
Moreover power corrections to the mean values of the observables mentioned
above were investigated considering the Milan factor and the improved
prediction for the jet broadening observables.
Our study, which considered e^+e^- data of five event shape observables
between \sqrt{s}= 14 and 183 GeV, yielded \alpha_s(M_{Z^0})=0.1177 +0.0035
-0.0034.Comment: 14 pages, LaTeX2e, 9 .eps-files included, abbreviated version of the
paper contributed to the ICHEP'98 conference in Vancouver, submitted to Phys.
Lett.
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