2,829 research outputs found
A cultural task analysis of implicit independence: Comparing North America, Western Europe, and East Asia.
Informed by a new theoretical framework that assigns a key role to cultural tasks (culturally prescribed means to achieve cultural mandates such as independence and interdependence) in mediating the mutual influences between culture and psychological processes, the authors predicted and found that North Americans are more likely than Western Europeans (British and Germans) to (a) exhibit focused (vs. holistic) attention, (b) experience emotions associated with independence (vs. interdependence), (c) associate happiness with personal achievement (vs. communal harmony), and (d) show an inflated symbolic self. In no cases were the 2 Western European groups significantly different from one another. All Western groups showed (e) an equally strong dispositional bias in attribution. Across all of the implicit indicators of independence, Japanese were substantially less independent (or more interdependent) than the three Western groups. An explicit self-belief measure of independence and interdependence showed an anomalous pattern. These data were interpreted to suggest that the contemporary American ethos has a significant root in both Western cultural heritage and a history of voluntary settlement. Further analysis offered unique support for the cultural task analysis
Is moderate hypofractionation accepted as a new standard of care in north america for prostate cancer patients treated with external beam radiotherapy? Survey of genitourinary expert radiation oncologists
INTRODUCTION:
Several recent randomized clinical trials have evaluated hypofractionated regimens against conventionally fractionated EBRT and shown similar effectiveness with conflicting toxicity results. The current view regarding hypofractionation compared to conventional EBRT among North American genitourinary experts for management of prostate cancer has not been investigated.
MATERIALS AND METHODS:
A survey was distributed to 88 practicing North American GU physicians serving on decision - making committees of cooperative group research organizations. Questions pertained to opinions regarding the default EBRT dose and fractionation for a hypothetical example of a favorable intermediate - risk prostate cancer (Gleason 3 + 4). Treatment recommendations were correlated with practice patterns using Fisher's exact test.
RESULTS:
Forty - two respondents (48%) completed the survey. We excluded from analysis two respondents who selected radical hypofractionation with 5 - 12 fractions as a preferred treatment modality. Among the 40 analyzed respondents, 23 (57.5%) recommend conventional fractionation and 17 (42.5%) recommended moderate hypofractionation. No demographic factors were found to be associated with preference for a fractionation regimen. Support for brachytherapy as a first choice treatment modality for low - risk prostate cancer was borderline significantly associated with support for moderate hypofractionated EBRT treatment modality (p = 0.089).
CONCLUSIONS:
There is an almost equal split among North American GU expert radiation oncologists regarding the appropriateness to consider moderately hypofractionated EBRT as a new standard of care in management of patients with prostate cancer. Physicians who embrace brachytherapy may be more inclined to support moderate hypofractionated regimen for EBRT. It is unclear whether reports with longer followups will impact this balance, or whether national care and reimbursement policies will drive the clinical decisions. In the day and age of patient - centered care delivery, patients should receive an objective recommendation based on available clinical evidence. The stark division among GU experts may influence the design of future clinical trials utilizing EBRT for patients with prostate cancer
Adjuvant vs. salvage radiation therapy in men with high-risk features after radical prostatectomy: Survey of North American genitourinary expert radiation oncologists
INTRODUCTION:
The management of patients with high-risk features after radical prostatectomy (RP) is controversial. Level 1 evidence demonstrates that adjuvant radiation therapy (RT) improves survival compared to no treatment; however, it may overtreat up to 30% of patients, as randomized clinical trials (RCTs) using salvage RT on observation arms failed to reveal a survival advantage of adjuvant RT. We, therefore, sought to determine the current view of adjuvant vs. salvage RT among North American genitourinary (GU) radiation oncology experts.
METHODS:
A survey was distributed to 88 practicing North American GU physicians serving on decision-making committees of cooperative group research organizations. Questions pertained to opinions regarding adjuvant vs. salvage RT for this patient population. Treatment recommendations were correlated with practice patterns using Fisher's exact test.
RESULTS:
Forty-two of 88 radiation oncologists completed the survey; 23 (54.8%) recommended adjuvant RT and 19 (45.2%) recommended salvage RT. Recommendation of active surveillance for Gleason 3+4 disease was a significant predictor of salvage RT recommendation (p=0.034), and monthly patient volume approached significance for recommendation of adjuvant over salvage RT; those seeing <15 patients/month trended towards recommending adjuvant over salvage RT (p=0.062). No other demographic factors approached significance.
CONCLUSIONS:
There is dramatic polarization among North American GU experts regarding optimal management of patients with high-risk features after RP. Ongoing RCTs will determine whether adjuvant RT improves survival over salvage RT. Until then, the almost 50/50 division seen from this analysis should encourage practicing clinicians to discuss the ambiguity with their patients
Cold collisions of heavy molecules with alkali-metal atoms in a magnetic field: Ab initio analysis and prospects for sympathetic cooling of SrOH by Li(S)
We use accurate ab initio and quantum scattering calculations to explore the
prospects for sympathetic cooling of the heavy molecular radical
SrOH() by ultracold Li atoms in a magnetic trap. A two-dimensional
potential energy surface (PES) for the triplet electronic state of Li-SrOH is
calculated ab initio using the partially spin-restricted coupled cluster method
with single, double and perturbative triple excitations and a large
correlation-consistent basis set. The highly anisotropic PES has a deep global
minimum in the skewed Li-HOSr geometry with cm and saddle
points in collinear configurations. Our quantum scattering calculations predict
low spin relaxation rates in fully spin-polarized Li+SrOH collisions with the
ratios of elastic to inelastic collision rates well in excess of 100 over a
wide range of magnetic fields (1-1000 G) and collision energies
(10~K) suggesting favorable prospects for sympathetic cooling of
SrOH molecules with spin-polarized Li atoms in a magnetic trap. We find that
spin relaxation in Li+SrOH collisions occurs via a direct mechanism mediated by
the magnetic dipole-dipole interaction between the electron spins of Li and
SrOH, and that the indirect (spin-rotation) mechanism is strongly suppressed.
The upper limit to the Li+SrOH reaction rate coefficient calculated for the
singlet PES using adiabatic capture theory is found to decrease from ~cm/s to a limiting value of cm/s with
decreasing temperature from 0.1 K to 1 K
Generation and Direct Detection of Broadband Mesoscopic Polarization-Squeezed Vacuum
Using a traveling-wave OPA with two orthogonally oriented type-I BBO crystals
pumped by picosecond pulses, we generate vertically and horizontally polarized
squeezed vacuum states within a broad range of wavelengths and angles.
Depending on the phase between these states, fluctuations in one or another
Stokes parameters are suppressed below the shot-noise limit. Due to the large
number of photon pairs produced, no local oscillator is required, and 3dB
squeezing is observed by means of direct detection.Comment: 4 pages, 4 figures, submitted to PR
CT dose reduction factors in the thousands using X-ray phase contrast
Phase-contrast X-ray imaging can improve the visibility of weakly absorbing
objects (e.g. soft tissues) by an order of magnitude or more compared to
conventional radiographs. Previously, it has been shown that combining phase
retrieval with computed tomography (CT) can increase the signal-to-noise ratio
(SNR) by up to two orders of magnitude over conventional CT at the same
radiation dose, without loss of image quality. Our experiments reveal that as
radiation dose decreases, the relative improvement in SNR increases. We
discovered this enhancement can be traded for a reduction in dose greater than
the square of the gain in SNR. Upon reducing the dose 300 fold, the
phase-retrieved SNR was still almost 10 times larger than the absorption
contrast data. This reveals the potential for dose reduction factors in the
tens of thousands without loss in image quality, which would have a profound
impact on medical and industrial imaging applications
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