3,273 research outputs found
Occupationally related illness: its compensation and its prevention
In the major industrialised nations of the Northern Hemisphere, it is now being recognised that the problem of work-related illness is one of considerable dimensions. Despite the advantage New Zealand enjoys with its Accident Compensation legislation, in such matters, we lag behind the best of overseas practice. The article examines the part that recognition of such illnesses for compensation purposes plays in highlighting the need for preventive measures and suggests that, unless more effort is put into research into causation and allied problems, the work connection will not be established. Thus, not only will compensation not be paid but also, preventive measures will not be instituted
Realistic Rashba and Dressehaus spin-orbit coupling for neutral atoms
We describe a new class of atom-laser coupling schemes which lead to
spin-orbit coupled Hamiltonians for ultra-cold neutral atoms. By properly
setting the optical phases, a pair of degenerate pseudospin states emerge as
the lowest energy states in the spectrum, and are thus immune to collisionally
induced decay. These schemes use cyclically coupled ground or metastable
internal states. We specialize to two situations: a three level case giving
fixed Rashba coupling, and a four-level case that adds a controllable
Dresselhaus contribution. We describe an implementation of the four level
scheme for \Rb87 and analyze the sensitivity of our approach to realistic
experimental limitations and imperfections. Lastly, we argue that no laser
coupling scheme can give pure Rashba or Dresselhaus coupling: akin to condensed
matter systems, higher order terms spoil the symmetry of these couplings.
However, for sufficiently intense laser fields the continuous rotational
symmetry approximately holds, making the Rashba Hamiltonian applicable for cold
atoms.Comment: 5 pages, 4 figures, accepted as a PRA Brief Repor
Occupationally related illness: its compensation and its prevention
In the major industrialised nations of the Northern Hemisphere, it is now being recognised that the problem of work-related illness is one of considerable dimensions. Despite the advantage New Zealand enjoys with its Accident Compensation legislation, in such matters, we lag behind the best of overseas practice. The article examines the part that recognition of such illnesses for compensation purposes plays in highlighting the need for preventive measures and suggests that, unless more effort is put into research into causation and allied problems, the work connection will not be established. Thus, not only will compensation not be paid but also, preventive measures will not be instituted
Landscape Influence on Canis Morphological and Ecological Variation in a Coyote-Wolf C. lupus × latrans Hybrid Zone, Southeastern Ontario
The ecology of Coyote-Wolf (Canis latrans × C. lupus) hybrids has never fully been typified. We studied morphological and ecological variation in Canis within a region of Coyote-Wolf hybridization in southeastern Ontario. We assessed Canis morphology from standard body measurements and ten skull measurements of adult specimens and found that Canis in this region are morphologically intermediate between Algonquin Provincial Park Wolves (C. lupus lycaon) and Coyotes, indicating a latrans × lycaon hybrid origin; however, there is a closer morphological affinity to latrans than lycaon. Analysis of 846 scats indicated dietary habits also intermediate between lycaon and Coyotes. We used a geographic information system (GIS) to assess spatial landscape features (road density, land cover and fragmentation) for six study sites representing three landscape types. We found noticeable variation in Canis morphology and diet in different landscape types. In general, canids from landscape type A (lowest road density, more total forest cover, less fragmentation) displayed more Wolf-like body morphology and consumed a greater proportion of larger prey (Beaver [Castor canadensis] and White-tailed Deer [Odocoileus virginianus]). In comparison, canids from landscape types B and C (higher road density and/or less total forest cover, more fragmentation) were generally more Coyote-like in body and skull morphology and made greater use of medium to small-sized prey (Groundhog [Marmota monax], Muskrat [Ondatra zibethicus] and lagomorphs). These landscape trends in Canis types suggest selection against Wolf-like traits in fragmented forests with high road density. The range of lycaon southeast of Algonquin Provincial Park appears to be limited primarily due to human access and consequent exploitation. We suggest that road density is the best landscape indicator of Canis types in this region of sympatric, hybridizing and unprotected Canis populations
LTE1 promotes exit from mitosis by multiple mechanisms
In budding yeast, alignment of the anaphase spindle along the mother–bud axis is crucial for maintaining genome integrity. If the anaphase spindle becomes misaligned in the mother cell compartment, cells arrest in anaphase because the mitotic exit network (MEN), an essential Ras-like GTPase signaling cascade, is inhibited by the spindle position checkpoint (SPoC). Distinct localization patterns of MEN and SPoC components mediate MEN inhibition. Most components of the MEN localize to spindle pole bodies. If the spindle becomes mispositioned in the mother cell compartment, cells arrest in anaphase due to inhibition of the MEN by the mother cell–restricted SPoC kinase Kin4. Here we show that a bud-localized activating signal is necessary for full MEN activation. We identify Lte1 as this signal and show that Lte1 activates the MEN in at least two ways. It inhibits small amounts of Kin4 that are present in the bud via its central domain. An additional MEN-activating function of Lte1 is mediated by its N- and C-terminal GEF domains, which, we propose, directly activate the MEN GTPase Tem1. We conclude that control of the MEN by spindle position is exerted by both negative and positive regulatory elements that control the pathway’s GTPase activity.National Institutes of Health (U.S.) (Grant HD085866)National Cancer Institute (U.S.)David H. Koch Institute for Integrative Cancer Research at MIT. Support (Core) (Grant P30-CA14051
Integrated TiO2 resonators for visible photonics
We demonstrate waveguide-coupled titanium dioxide (TiO2) racetrack resonators
with loaded quality factors of 2x10^4 for the visible wavelengths. The
structures were fabricated in sputtered TiO2 thin films on oxidized silicon
substrates using standard top-down nanofabrication techniques, and passively
probed in transmission measurements using a tunable red laser. Devices based on
this material could serve as integrated optical elements as well as passive
platforms for coupling to visible quantum emitters.Comment: 4 pages, 3 figure
The Effect of Statin Therapy on Heart Failure Events: A Collaborative Meta-Analysis of Unpublished Data from Major Randomized Trials
Aims: The effect of statins on risk of heart failure (HF) hospitalization and HF death remains uncertain. We aimed to establish whether statins reduce major HF events. Methods and results: We searched Medline, EMBASE, and the Cochrane Central Register of Controlled Trials for randomized controlled endpoint statin trials from 1994 to 2014. Collaborating trialists provided unpublished data from adverse event reports. We included primary- and secondary-prevention statin trials with \u3e1000 participants followed for \u3e1 year. Outcomes consisted of first non-fatal HF hospitalization, HF death and a composite of first non-fatal HF hospitalization or HF death. HF events occurring(MI) were excluded. We calculated risk ratios (RR) with fixed-effects meta-analyses. In up to 17 trials with 132 538 participants conducted over 4.3 [weighted standard deviation (SD) 1.4] years, statin therapy reduced LDL-cholesterol by 0.97 mmol/L (weighted SD 0.38 mmol/L). Statins reduced the numbers of patients experiencing non-fatal HF hospitalization (1344/66 238 vs. 1498/66 330; RR 0.90, 95% confidence interval, CI 0.84–0.97) and the composite HF outcome (1234/57 734 vs. 1344/57 836; RR 0.92, 95% CI 0.85–0.99) but not HF death (213/57 734 vs. 220/57 836; RR 0.97, 95% CI 0.80–1.17). The effect of statins on first non-fatal HF hospitalization was similar whether this was preceded by MI (RR 0.87, 95% CI 0.68–1.11) or not (RR 0.91, 95% CI 0.84–0.98). Conclusion: In primary- and secondary-prevention trials, statins modestly reduced the risks of non-fatal HF hospitalization and a composite of non-fatal HF hospitalization and HF death with no demonstrable difference in risk reduction between those who suffered an MI or not
Polarons as Nucleation Droplets in Non-Degenerate Polymers
We present a study of the nucleation mechanism that allows the decay of the
metastable phase (trans-cisoid) to the stable phase
(cis-transoid) in quasi one-dimensional non-degenerate polymers within the
continuum electron-phonon model. The electron-phonon configurations that lead
to the decay, i.e. the critical droplets (or transition state), are identified
as polarons of the metastable phase. We obtain an estimate for the decay rate
via thermal activation within a range of parameters consistent with
experimental values for the gap of the cis-configuration. It is pointed out
that, upon doping, the activation barriers of the excited states are quite
smaller and the decay rate is greatly enhanced. Typical activation energies for
electron or hole polarons are eV and the typical size for a
critical droplet (polaron) is about . Decay via quantum nucleation is
also studied and it is found that the crossover temperature between quantum
nucleation and thermal activation is of order . Metastable
configurations of non-degenerate polymers may provide examples for mesoscopic
quantum tunneling.Comment: REVTEX 3.0, 28 PAGES, 3 FIGURES AVAILABLE UPON REQUEST, PITT 94-0
Risk algorithm using serial biomarker measurements doubles the number of screen-detected cancers compared with a single-threshold rule in the United Kingdom collaborative trial of ovarian cancer screening
PURPOSE: Cancer screening strategies have commonly adopted single-biomarker thresholds to identify abnormality. We investigated the impact of serial biomarker change interpreted through a risk algorithm on cancer detection rates.
PATIENTS AND METHODS: In the United Kingdom Collaborative Trial of Ovarian Cancer Screening, 46,237 women, age 50 years or older underwent incidence screening by using the multimodal strategy (MMS) in which annual serum cancer antigen 125 (CA-125) was interpreted with the risk of ovarian cancer algorithm (ROCA). Women were triaged by the ROCA: normal risk, returned to annual screening; intermediate risk, repeat CA-125; and elevated risk, repeat CA-125 and transvaginal ultrasound. Women with persistently increased risk were clinically evaluated. All participants were followed through national cancer and/or death registries. Performance characteristics of a single-threshold rule and the ROCA were compared by using receiver operating characteristic curves.
RESULTS: After 296,911 women-years of annual incidence screening, 640 women underwent surgery. Of those, 133 had primary invasive epithelial ovarian or tubal cancers (iEOCs). In all, 22 interval iEOCs occurred within 1 year of screening, of which one was detected by ROCA but was managed conservatively after clinical assessment. The sensitivity and specificity of MMS for detection of iEOCs were 85.8% (95% CI, 79.3% to 90.9%) and 99.8% (95% CI, 99.8% to 99.8%), respectively, with 4.8 surgeries per iEOC. ROCA alone detected 87.1% (135 of 155) of the iEOCs. Using fixed CA-125 cutoffs at the last annual screen of more than 35, more than 30, and more than 22 U/mL would have identified 41.3% (64 of 155), 48.4% (75 of 155), and 66.5% (103 of 155), respectively. The area under the curve for ROCA (0.915) was significantly (P = .0027) higher than that for a single-threshold rule (0.869).
CONCLUSION: Screening by using ROCA doubled the number of screen-detected iEOCs compared with a fixed cutoff. In the context of cancer screening, reliance on predefined single-threshold rules may result in biomarkers of value being discarded
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