129 research outputs found
Probing the high momentum component of the deuteron at high Q^2
The d(e,e'p) cross section at a momentum transfer of 3.5 (GeV/c)^2 was
measured over a kinematical range that made it possible to study this reaction
for a set of fixed missing momenta as a function of the neutron recoil angle
theta_nq and to extract missing momentum distributions for fixed values of
theta_nq up to 0.55 GeV/c. In the region of 35 (deg) <= theta_nq <= 45 (deg)
recent calculations, which predict that final state interactions are small,
agree reasonably well with the experimental data. Therefore these experimental
reduced cross sections provide direct access to the high momentum component of
the deuteron momentum distribution in exclusive deuteron
electro-disintegration.Comment: 5 pages, 2 figure
Love stories can be unpredictable: Jules et Jim in the vortex of life
Love stories are dynamic processes that begin, develop, and often stay for a relatively long time in stationary or fluctuating regime, before possibly fading. Although they are, undoubtedly, the most important dynamic process in our life, they have only recently been cast in the formal frame of dynamical systems theory. In particular, why it is so difficult to predict the evolution of sentimental relationships continues to be largely unexplained. A common reason for this is that love stories reflect the turbulence of the surrounding social environment. But we can also imagine that the interplay of the characters involved contributes to make the story unpredictable, that is, chaotic. In other words, we conjecture that sentimental chaos can have a relevant endogenous origin. To support this intriguing conjecture, we mimic a real and well-documented love story with a mathematical model in which the environment is kept constant, and show that the model is chaotic. The case we analyze is the triangle described in Jules et Jim, an autobiographic novel by Henri-Pierr Roche that became famous worldwide after the success of the homonymous film directed by Fran8cois Truffaut
The Quasielastic 3He(e,e'p)d Reaction at Q^2 = 1.5 GeV^2 for Recoil Momenta up to 1 GeV/c
We have studied the quasielastic 3He(e,e'p)d reaction in perpendicular
coplanar kinematics, with the energy and momentum transferred by the electron
fixed at 840 MeV and 1502 MeV/c, respectively. The 3He(e,e'p)d cross section
was measured for missing momenta up to 1000 MeV/c, while the A_TL asymmetry was
extracted for missing momenta up to 660 MeV/c. For missing momenta up to 150
MeV/c, the measured cross section is described well by calculations that use a
variational ground-state wave function of the 3He nucleus derived from a
potential that includes three-body forces. For missing momenta from 150 to 750
MeV/c, strong final-state interaction effects are observed. Near 1000 MeV/c,
the experimental cross section is more than an order of magnitude larger than
predicted by available theories. The A_TL asymmetry displays characteristic
features of broken factorization, and is described reasonably well by available
models.Comment: 5 pages, 3 figures, submitted to Physical Review Letters, v3: changed
conten
Measurement of the 3He(e,e'p)pn reaction at high missing energies and momenta
Results of the Jefferson Lab Hall A quasielastic 3He(e,e'p)pn measurements
are presented. These measurements were performed at fixed transferred momentum
and energy, q = 1502 MeV/c and omega = 840 MeV, respectively, for missing
momenta p_m up to 1 GeV/c and missing energies in the continuum region, up to
pion threshold; this kinematic coverage is much more extensive than that of any
previous experiment. The cross section data are presented along with the
effective momentum density distribution and compared to theoretical models.Comment: 5 pages, 3 figures, updated to reflect published paper: minor text
changes from previous version along with updated and added reference
Participants' uptake of clinical trial results: a randomised experiment
BJC OPENInternational audienceBACKGROUND: Participants are showing great interest these days in obtaining the results of clinical trials. The aim of this study was to assess patients' uptake and understanding of the results of the trial in which they have participated and the impact of a letter offering patients the possibility of consulting the trial results on a specific website. METHODS: Breast cancer patients participating in a trial on the efficacy of Trastuzumab were randomly subdivided into an Internet group (who received the letter of invitation) and a control group (who did not receive it). Among 115 HER2-positive women from 21 centres, 107 (93%) answered a self-administered questionnaire. RESULTS: Most of the patients in both groups had access to the Internet (72.0%). The majority (97.2%) stated that receiving information about the trial results would be useful, and the oncologist was the most frequently preferred information provider. The Internet group's declared uptake of the trial results was only slightly higher (47.1% vs 33.9%; P=0.166); however, they understood the results significantly more accurately (18.8% vs 5.6%; P=0.039). INTERPRETATION: Although Internet was not the respondents' preferred source of information, the possibility of using this source slightly increased the uptake and understanding of the results
Precision Measurement of the Neutron Spin Asymmetries and Spin-dependent Structure Functions in the Valence Quark Region
We report on measurements of the neutron spin asymmetries and
polarized structure functions at three kinematics in the deep
inelastic region, with , 0.47 and 0.60 and , 3.5 and 4.8
(GeV/c), respectively. These measurements were performed using a 5.7 GeV
longitudinally-polarized electron beam and a polarized He target. The
results for and at are consistent with previous world
data and, at the two higher points, have improved the precision of the
world data by about an order of magnitude. The new data show a zero
crossing around and the value at is significantly positive.
These results agree with a next-to-leading order QCD analysis of previous world
data. The trend of data at high agrees with constituent quark model
predictions but disagrees with that from leading-order perturbative QCD (pQCD)
assuming hadron helicity conservation. Results for and have a
precision comparable to the best world data in this kinematic region. Combined
with previous world data, the moment was evaluated and the new result
has improved the precision of this quantity by about a factor of two. When
combined with the world proton data, polarized quark distribution functions
were extracted from the new values based on the quark parton
model. While results for agree well with predictions from various
models, results for disagree with the leading-order pQCD
prediction when hadron helicity conservation is imposed.Comment: A typing error in A_\parallel(3He) at x=0.47 in Table VII of Phys.
Rev. C has been noticed and correcte
Recoil Polarization Measurements for Neutral Pion Electroproduction at Q^2=1 (GeV/c)^2 Near the Delta Resonance
We measured angular distributions of differential cross section, beam
analyzing power, and recoil polarization for neutral pion electroproduction at
Q^2 = 1.0 (GeV/c)^2 in 10 bins of W across the Delta resonance. A total of 16
independent response functions were extracted, of which 12 were observed for
the first time. Comparisons with recent model calculations show that response
functions governed by real parts of interference products are determined
relatively well near 1.232 GeV, but variations among models is large for
response functions governed by imaginary parts and for both increases rapidly
with W. We performed a nearly model-independent multipole analysis that adjusts
complex multipoles with high partial waves constrained by baseline models.
Parabolic fits to the W dependence of the multipole analysis around the Delta
mass gives values for SMR = (-6.61 +/- 0.18)% and EMR = (-2.87 +/- 0.19)% that
are distinctly larger than those from Legendre analysis of the same data.
Similarly, the multipole analysis gives Re(S0+/M1+) = (+7.1 +/- 0.8)% at
W=1.232 GeV, consistent with recent models, while the traditional Legendre
analysis gives the opposite sign because its truncation errors are quite
severe. Finally, using a unitary isobar model (UIM), we find that excitation of
the Roper resonance is dominantly longitudinal with S1/2 = (0.05 +/- 0.01)
GeV^(-1/2) at Q^2=1. The ReS0+ and ReE0+ multipoles favor pseudovector coupling
over pseudoscalar coupling or a recently proposed mixed-coupling scheme, but
the UIM does not reproduce the imaginary parts of 0+ multipoles well.Comment: 60 pages, 54 figure
Clinical pharmacodynamic factors in docetaxel toxicity
Neutropenia is the main dose-limiting toxicity occurring in docetaxel treatment. The objective of this study was to identify pharmacodynamic (PD) factors responsible for the neutropaenia caused by docetaxel. Data were obtained from 92 patients treated with docetaxel as a monochemotherapy in two different treatment centres. A semiphysiological population pharmacokineticâpharmacodynamic (PK/PD) model was applied to describe the time course of neutrophils and the neutropaenic effect of docetaxel. The plasma docetaxel concentration was assumed to inhibit the proliferation of neutrophil precursors through a linear model: Drug effect=Slope Ă Conc. Slope corresponds to the patients' sensitivity to the neutropaenic effect of docetaxel. Covariate analysis was performed by testing the relationship between the patients' characteristics and Slope using the program NONMEM. The neutropaenic effect of docetaxel showed a high interindividual variability. Three significant PD covariates were identified: serum α1-acid glycoprotein levels (AAG), level of chemotherapy pretreatment, and treatment centre. Extensive pretreatment was associated with an increase in Slope values meaning a higher haematotoxicity. An increase in AAG was associated with a decrease of both Slope and docetaxel plasma clearance. Patients treated in one centre had both higher Slope and docetaxel clearance. The centre effect (most likely due to a bias in the PK part of the study between the two centres) reveals the robustness of the PK/PD model. Individual dosing of docetaxel should be based on previous chemotherapy but not on the AAG level since it has a similar influence on PD and PK docetaxel parameters. This methodology should be applied to further investigate elderly patients and to identify more precisely the characteristics of previous chemotherapy that contribute to the cumulative myelotoxicity
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