265 research outputs found
Individual addressing and state readout of trapped ions utilizing rf- micromotion
A new scheme for the individual addressing of ions in a trap is described
that does not rely on light beams tightly focused onto only one ion. The scheme
utilizes ion micromotion that may be induced in a linear trap by dc offset
potentials. Thus coupling an individual ion to the globally applied light
fields corresponds to a mere switching of voltages on a suitable set of
compensation electrodes. The proposed scheme is especially suitable for
miniaturized rf (Paul) traps with typical dimensions of about 20-40 microns.Comment: 3 pages, 5 figure
Hidden magnetic transitions in thermoelectric layered cobaltite, [CaCoO][CoO]
A positive muon spin rotation and relaxation (SR) experiment on
[CaCoO][CoO], ({\sl i.e.}, CaCoO, a layered
thermoelectric cobaltite) indicates the existence of two magnetic transitions
at 100 K and 400 - 600 K; the former is a transition from a paramagnetic
state to an incommensurate ({\sf IC}) spin density wave ({\sf SDW}) state. The
anisotropic behavior of zero-field SR spectra at 5 K suggests that the
{\sf IC-SDW} propagates in the - plane, with oscillating moments directed
along the c-axis; also the {\sf IC-SDW} is found to exist not in the
[CaCoO] subsystem but in the [CoO] subsystem. In addition, it is
found that the long-range {\sf IC-SDW} order completes below 30 K,
whereas the short-range order appears below 100 K. The latter transition is
interpreted as a gradual change in the spin state of Co ions %% at temperatures
above 400 K. These two magnetic transitions detected by SR are found to
correlate closely with the transport properties of
[CaCoO][CoO].Comment: 7 pages, 8 figures. to be appeared in Phys. Rev.
Analysis of Exertion-Related Injuries and Fatalities in Laborers in the United States
Laborers are particularly vulnerable to exertional injuries and illnesses, as they often engage in heavy physical work for prolonged hours, yet no studies have examined the top causes of catastrophic exertional injuries and fatalities among this population. The purpose of the investigation was to characterize the top causes of exertional injury and fatality within open access, Occupational Safety and Health Administration (OSHA) reportable data. A secondary analysis of OSHA reported injury and fatality data was performed through open access records from OSHA Severe Injury Reports (2015â2022) and OSHA fatality inspection data (2017â2020), respectively. The research team characterized each reported injury and fatality as âexertion-relatedâ or ânon-exertion-related. Injury and fatality rates were reported per 100,000 equivalent full-time worker years and included 95% confidence intervals (95% CI). Of 58,648 cases in the OSHA Severe Injury Report database from 2015â2020, 1682 cases (2.9%) were characterized as exertional (0.20 injuries per 100,000 full-time worker years, 95% CI: 0.19, 0.22). Heat-related injuries encompassed 91.9% of the exertional injuries (n = 1546). From the 2017â2022 OSHA fatality inspection database, 89 (1.9%) of 4598 fatalities were characterized as exertion-related (fatality rate: 0.0160 per 100,000 full-time equivalent workers, 95% CI: 0.009, 0.0134). The exertion-related fatalities primarily consisted of heat-related cases (87.6%). Exertion-related injuries and fatalities were most reported in Southeast states, in the construction and excavation industry, and among nonunionized workers. As heat stress continues to be recognized as an occupational health and safety hazard, this analysis further highlights the need for targeted interventions or further evaluation of the impact of heat stress on construction and excavation workers, nonunionized workers, and workers in Southeastern states
Projection Postulate and Atomic Quantum Zeno Effect
The projection postulate has been used to predict a slow-down of the time
evolution of the state of a system under rapidly repeated measurements, and
ultimately a freezing of the state. To test this so-called quantum Zeno effect
an experiment was performed by Itano et al. (Phys. Rev. A 41, 2295 (1990)) in
which an atomic-level measurement was realized by means of a short laser pulse.
The relevance of the results has given rise to controversies in the literature.
In particular the projection postulate and its applicability in this experiment
have been cast into doubt. In this paper we show analytically that for a wide
range of parameters such a short laser pulse acts as an effective level
measurement to which the usual projection postulate applies with high accuracy.
The corrections to the ideal reductions and their accumulation over n pulses
are calculated. Our conclusion is that the projection postulate is an excellent
pragmatic tool for a quick and simple understanding of the slow-down of time
evolution in experiments of this type. However, corrections have to be
included, and an actual freezing does not seem possible because of the finite
duration of measurements.Comment: 25 pages, LaTeX, no figures; to appear in Phys. Rev.
Muon spin relaxation studies of incommensurate magnetism and superconductivity in stage-4 LaCuO and LaSrCuO
This paper reports muon spin relaxation (MuSR) measurements of two single
crystals of the title high-Tc cuprate systems where static incommensurate
magnetism and superconductivity coexist. By zero-field MuSR measurements and
subsequent analyses with simulations, we show that (1) the maximum ordered Cu
moment size (0.36 Bohr magneton) and local spin structure are identical to
those in prototypical stripe spin systems with the 1/8 hole concentration; (2)
the static magnetism is confined to less than a half of the volume of the
sample, and (3) regions with static magnetism form nano-scale islands with the
size comparable to the in-plane superconducting coherence length. By
transverse-field MuSR measurements, we show that Tc of these systems is related
to the superfluid density, in the same way as observed in cuprate systems
without static magnetism. We discuss a heuristic model involving percolation of
these nanoscale islands with static magnetism as a possible picture to
reconcile heterogeneity found by the present MuSR study and long-range spin
correlations found by neutron scattering.Comment: 19 pages, 15 figures, submitted to Phys. Rev. B. E-mail:
[email protected]
Cosmological distance indicators
We review three distance measurement techniques beyond the local universe:
(1) gravitational lens time delays, (2) baryon acoustic oscillation (BAO), and
(3) HI intensity mapping. We describe the principles and theory behind each
method, the ingredients needed for measuring such distances, the current
observational results, and future prospects. Time delays from strongly lensed
quasars currently provide constraints on with < 4% uncertainty, and with
1% within reach from ongoing surveys and efforts. Recent exciting discoveries
of strongly lensed supernovae hold great promise for time-delay cosmography.
BAO features have been detected in redshift surveys up to z <~ 0.8 with
galaxies and z ~ 2 with Ly- forest, providing precise distance
measurements and with < 2% uncertainty in flat CDM. Future BAO
surveys will probe the distance scale with percent-level precision. HI
intensity mapping has great potential to map BAO distances at z ~ 0.8 and
beyond with precisions of a few percent. The next years ahead will be exciting
as various cosmological probes reach 1% uncertainty in determining , to
assess the current tension in measurements that could indicate new
physics.Comment: Review article accepted for publication in Space Science Reviews
(Springer), 45 pages, 10 figures. Chapter of a special collection resulting
from the May 2016 ISSI-BJ workshop on Astronomical Distance Determination in
the Space Ag
Creation and impact of containment units with high-risk zones during the coronavirus disease 2019 (COVID-19) pandemic
Background: The rapid spread of coronavirus disease 2019 (COVID-19) required swift preparation to protect healthcare personnel (HCP) and patients, especially considering shortages of personal protective equipment (PPE). Due to the lack of a pre-existing biocontainment unit, we needed to develop a novel approach to placing patients in isolation cohorts while working with the pre-existing physical space. Objectives: To prevent disease transmission to nonâCOVID-19 patients and HCP caring for COVID-19 patients, to optimize PPE usage, and to provide a comfortable and safe working environment. Methods: An interdisciplinary workgroup developed a combination of approaches to convert existing spaces into COVID-19 containment units with high-risk zones (HRZs). We developed standard workflow and visual management in conjunction with updated staff training and workflows. The infection prevention team created PPE standard practices for ease of use, conservation, and staff safety. Results: The interventions resulted in 1 possible case of patient-to-HCP transmission and zero cases of patient-to-patient transmission. PPE usage decreased with the HRZ model while maintaining a safe environment of care. Staff on the COVID-19 units were extremely satisfied with PPE availability (76.7%) and efforts to protect them from COVID-19 (72.7%). Moreover, 54.8% of HCP working in the COVID-19 unit agreed that PPE monitors played an essential role in staff safety. Conclusions: The HRZ model of containment unit is an effective method to prevent the spread of COVID-19 with several benefits. It is easily implemented and scaled to accommodate census changes. Our experience suggests that other institutions do not need to modify existing physical structures to create similarly protective spaces
An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics
For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types
Supervisors' Perceptions of the Performance of Cooperative Education Employees Working in Federal Agencies
Through cooperative education programs, many public agencies employ college students part time or intermittently and groom them for future full-time employment The combination of winnowing and nurturing that occurs in these programs is believed to produce higher performing employees This study tests this hypothesis by comparing Federal supervisors' perceptions of the performance of co-op employees with those recruited from other sources Data come from the 1992 Merit Principles Survey, US Merit Systems Protection Board The results indicate that co-op employees perform at high levels, but they do not outperform other employees as a whole Next, we compare the performance ratings of Federal workers from seven other recruitment sources to see if any source is superior Some interesting findings emerge Of course, performance ratings are an incomplete indicator of an employee's value to the organization These ratings merely reflect supervisors' perceptions, and while high performance is important, agencies may wish to promote other goals in their recruitment and retention efforts such as workforce diversityYeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline
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