305 research outputs found
Tunneling with dissipation and decoherence for a large spin
We present rigorous solution of problems of tunneling with dissipation and
decoherence for a spin of an atom or a molecule in an isotropic solid matrix.
Our approach is based upon switching to a rotating coordinate system coupled to
the local crystal field. We show that the spin of a molecule can be used in a
qubit only if the molecule is strongly coupled with its atomic environment.
This condition is a consequence of the conservation of the total angular
momentum (spin + matrix), that has been largely ignored in previous studies of
spin tunneling.Comment: 4 page
Micro-Hall Magnetometry Studies of Thermally Assisted and Pure Quantum Tunneling in Single Molecule Magnet Mn12-Acetate
We have studied the crossover between thermally assisted and pure quantum
tunneling in single crystals of high spin (S=10) uniaxial single molecule
magnet Mn12-acetate using micro-Hall effect magnetometry. Magnetic hysteresis
experiments have been used toinvestigate the energy levels that determine the
magnetization reversal as a function of magnetic field and temperature. These
experiments demonstrate that the crossover occurs in a narrow (~0.1 K) or broad
(~1 K) temperature interval depending on the magnitude and direction of the
applied field. For low external fields applied parallel to the easy axis, the
energy levels that dominate the tunneling shift abruptly with temperature. In
the presence of a transverse field and/or large longitudinal field these energy
levels change with temperature more gradually. A comparison of our experimental
results with model calculations of this crossover suggest that there are
additional mechanisms that enhance the tunneling rate of low lying energy
levels and broaden the crossover for small transverse fields.Comment: 5 pages, 5 figure
Patient characteristics and health system factors associated with adjuvant radiation therapy receipt in older women with early-stage endometrial cancer
Introduction: Among women with early-stage endometrial cancer (EC), age, stage, grade, and histology are used to determine fitness for adjuvant radiation therapy (RT) administration. We examined non-cancer factors associated with adjuvant RT receipt in older women with early-stage EC. Materials & methods: Using data from the Surveillance Epidemiology and End Results cancer registry program linked with Medicare claims, we identified 25,654 women (aged ≥66 years) diagnosed with first primary stage I-II EC during 2004–2017 who underwent a hysterectomy. Diagnosis and procedure codes were used to identify adjuvant RT claims filed for the seven-month period post-hysterectomy. Multivariable log-binomial regression was used to estimate adjuvant RT prevalence associated with patient characteristics and health system factors after adjustment for age, frailty, and endometrial factors. Results: Adjuvant RT was less commonly administered to Asian American and Pacific Islander patients than non-Hispanic White patients (Prevalence ratio [PR], 0.84; 95% confidence interval [CI], 0.73 to 0.97). Compared to women treated in the Northeast region, women treated other regions of the US were less likely to undergo adjuvant RT (PR, 0.75; 95% CI, 0.71 to 0.79). Residing in rural or high neighborhood-poverty counties was associated with lower adjuvant RT administration. Higher comorbidity score was not associated with reduced prevalence of adjuvant RT receipt; however, women with high probability of predicted probability of frailty were less likely to undergo adjuvant RT (PR, 0.67; 95% CI, 0.55 to 0.81) compared to women with low probability of frailty. Women who received lymph node assessment were more likely to undergo adjuvant RT compared to women who did not (PR, 1.43; 95% CI, 1.34 to 1.51). Women treated by a gynecologic oncologist were more likely to undergo adjuvant RT compared to women treated by a non-gynecologic oncologist (PR 1.09; 95% CI, 1.04 to 1.14). Adjuvant RT was more commonly administered to women treated in larger academic hospitals. Discussion: Findings suggest that various non-cancer factors affect the delivery of adjuvant RT to older women with early-stage EC in real-world oncology practice. Advancing our understanding of factors associated with adjuvant RT administration may help expand equitable access to RT
Adjuvant radiation therapy and health-related quality of life among older women with early-stage endometrial cancer: an analysis using the SEER-MHOS linkage
Purpose: Radiation therapy (RT) has been associated with decreased health-related quality of life (HRQOL) in clinical trials of early-stage endometrial cancer (EC), but few studies have examined the association in real-world settings. We assessed HRQOL associated with adjuvant RT for older women with early-stage EC within a large U.S. population-based registry resource. Methods: The Surveillance Epidemiology and End Results and the Medicare Health Outcomes Survey linkage (1998–2017) was used to identify women with early-stage EC aged ≥ 65 years at survey who received surgery and were diagnosed ≥ 1-year prior (n = 1,140). HRQOL was evaluated with the 36-item Short-Form Health Survey (SF-36) until 2006 and the Veterans RAND 12-Item Health Survey (VR-12) post 2006. Ordinary least squares regression was used to estimate mean difference (MD) in T scores and 95% confidence intervals (CIs) comparing treatment groups (surgery alone, adjuvant external beam radiation therapy [EBRT], or adjuvant vaginal brachytherapy [VBT]) after accounting for confounders using propensity score weighting. Results: Overall, RT was not associated with physical health (MD = 0.97; 95% CI = − 1.13, 3.07) or mental health (MD = − 0.78; 95% CI = − 2.60, 1.05) relative to surgery alone. In analyses by RT type, adjuvant VBT was associated with better general health on the SF-36/VR-12 subscale (MD = 3.59; 95% CI = 0.56, 6.62) relative to surgery alone. No statistically significant associations were observed for adjuvant VBT and physical or mental health, or for adjuvant EBRT and any HRQOL domain. Conclusion: Older women with early-stage EC treated with adjuvant RT did not report worse physical and mental HRQOL scores compared to those treated with surgery alone, though relevant symptoms should be evaluated further to fully understand the disease and treatment specific aspects of the HRQOL
Real-world treatment patterns and outcomes for patients with advanced melanoma treated with immunotherapy or targeted therapy
Objective: To identify real-world patterns of first line treatment, treatment sequence and outcomes for older adults diagnosed with advanced melanoma who received immunotherapy or targeted therapy. Methods: The study population included older adults (ages 65+) diagnosed with unresectable or metastatic melanoma between 2012 and 2017 and who received first line immunotherapy or targeted therapy. Using the linked surveillance, epidemiology, and end results-medicare data, we described patterns of first line treatment and treatment sequence through 2018. We used descriptive statistics to report patient and provider characteristics by first line treatment receipt and changes in first line therapy use over calendar time. We also described overall survival (OS) and time to treatment failure (TTF) by first line treatment using the Kaplan–Meier method. For patterns of treatment sequence, we reported commonly observed treatment switch patterns by treatment sub-category and calendar year. Results: The analyses included 584 patients (mean age = 76.3 years). A majority (n = 502) received first line immunotherapy. There was a sustained increase in immunotherapy uptake, most notably from 2015 to 2016. The estimated median OS and TTF were longer with first line immunotherapy than with targeted therapy. Individuals treated with CTLA-4 + PD-1 inhibitors had the longest median OS (28.4 months). The most common treatment switch pattern was from a first line CTLA-4 inhibitor to a second line PD-1 inhibitor. Conclusions: Our findings inform understanding of treatment patterns of currently used immunotherapies and targeted therapies in older adults with advanced melanoma. Immunotherapy use has increased steadily with PD-1 inhibitors becoming a dominant treatment option since 2015
In-Vivo T-Cell Depletion Using Thymoglobulin (Thymo) Allows Successful Allogeneic Stem Cell Transplantation (Allo-SCT) From Mismatched, Unrelated Donors (MM-URD): Potential Influence Of Graft Source On Outcome
Cosmological parameters from SDSS and WMAP
We measure cosmological parameters using the three-dimensional power spectrum
P(k) from over 200,000 galaxies in the Sloan Digital Sky Survey (SDSS) in
combination with WMAP and other data. Our results are consistent with a
``vanilla'' flat adiabatic Lambda-CDM model without tilt (n=1), running tilt,
tensor modes or massive neutrinos. Adding SDSS information more than halves the
WMAP-only error bars on some parameters, tightening 1 sigma constraints on the
Hubble parameter from h~0.74+0.18-0.07 to h~0.70+0.04-0.03, on the matter
density from Omega_m~0.25+/-0.10 to Omega_m~0.30+/-0.04 (1 sigma) and on
neutrino masses from <11 eV to <0.6 eV (95%). SDSS helps even more when
dropping prior assumptions about curvature, neutrinos, tensor modes and the
equation of state. Our results are in substantial agreement with the joint
analysis of WMAP and the 2dF Galaxy Redshift Survey, which is an impressive
consistency check with independent redshift survey data and analysis
techniques. In this paper, we place particular emphasis on clarifying the
physical origin of the constraints, i.e., what we do and do not know when using
different data sets and prior assumptions. For instance, dropping the
assumption that space is perfectly flat, the WMAP-only constraint on the
measured age of the Universe tightens from t0~16.3+2.3-1.8 Gyr to
t0~14.1+1.0-0.9 Gyr by adding SDSS and SN Ia data. Including tensors, running
tilt, neutrino mass and equation of state in the list of free parameters, many
constraints are still quite weak, but future cosmological measurements from
SDSS and other sources should allow these to be substantially tightened.Comment: Minor revisions to match accepted PRD version. SDSS data and ppt
figures available at http://www.hep.upenn.edu/~max/sdsspars.htm
Soil Organic Carbon and Nitrogen Feedbacks on Crop Yields under Climate Change
Articles in A&EL are published under the CC-BY NC ND (non-commercial; no derivatives) license (https://creativecommons.org/licenses/by-nc-nd/2.0/). Users are free to copy and redistribute the material in any medium or format. Any further publication of the article will require proper attribution; no derivative works may be made from this article; and the article may not be used for any commercial gain (https://creativecommons.org/licenses/by-nc-nd/2.0/). The author is given explicit permission to publish the final article in her/his institutional repository. There is an option for the CC-BY license if required by an author's institution.Peer reviewedPublisher PD
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Junior staffing changes and the temporal ecology of adverse incidents in acute psychiatric wards
Aim. This paper reports an examination of the relationship between adverse incident rates, the arrival of new junior staff on wards, and days of the week on acute psychiatric wards.
Background. Incidents of violence, absconding and self-harm in acute inpatient services pose risks to patients and staff. Previous research suggests that the arrival of inexperienced new staff may trigger more adverse incidents. Findings on the relationship between incidents and the weekly routine are inconsistent.
Method. A retrospective analysis was conducted of formally reported incident rates, records of nursing student allocations and junior doctor rotation patterns, using Poisson Regression. Variance between days of the week was explored using contingency table analysis. The data covered 30 months on 17 psychiatric wards, and were collected in 2002–2004.
Findings. The arrival of new and inexperienced staff on the wards was not associated with increases in adverse incident rates. Most types of incidents were less frequent at weekends and midweek. Incident rates were unchanged on ward-round days, but increased rates were found on the days before and after ward rounds.
Conclusion. Increased patient tension is associated with raised incident rates. It may be possible to reduce incident rates by moderating stimulation in the environment and by mobilizing support for patients during critical periods
Floristic variations in a woody plant community along a trail in a Semideciduous Seasonal Forest, Viçosa, Minas Gerais State, Brazil
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