How to identify and recruit nurses to a survey 14 and 24 years after graduation in a context of scarce data: lessons learnt from the 2012 nurses at work pilot study on nurses' career paths.

BACKGROUND: Nursing workforce data are scarce in Switzerland, with no active national registry of nurses. The worldwide nursing shortage is also affecting Switzerland, so that evidence-based results of the nurses at work project on career paths and retention are needed as part of the health care system stewardship; nurses at work is a retrospective cohort study of nurses who graduated in Swiss nursing schools in the last 30 years. Results of the pilot study are presented here (process and feasibility). The objectives are (1) to determine the size and structure of the potential target population by approaching two test-cohorts of nursing graduates (1988 and 1998); (2) to test methods of identifying and reaching them 14 and 24 years after graduation; (3) to compute participation rates, and identify recruitment and participation biases. METHODS: Graduates' names were retrieved from 26 Swiss nursing schools: 488 nurses from the 1988 cohort and 597 from 1998 were invited to complete a web-based questionnaire. Initial updated addresses (n = 278, seed sample) were found using the Swiss Nursing Association member file. In addition, a snowball method was applied for recruitment, where directly-contacted respondents provided additional names of graduate mates or sent them the invitation. The study was further advertized through the main employers, study partners, and a press release. RESULTS: Participation rate was 26.5% (n = 287), higher for the older cohort of 1988 (29.7%, n = 145) than for 1998 (15.6%, n = 93). Additional nurses (n = 363) not belonging to the test cohorts also answered. All schools were represented among respondents. Only 18 respondents (6%) worked outside nursing or not at all. Among respondents, 94% would 'probably' or 'maybe' agree to participate in the main study. CONCLUSION: The pilot study demonstrated that targeted nurses could be identified and approached. There is an overwhelming interest in the project from them and from policymakers. Recommendations to increase nurses' participation rate for nurses at work include: (1) to open nurses at work recruitment to all nurses in Switzerland, while recreating cohorts post-hoc for relevant analysis; (2) to define a comprehensive communication strategy with special attention to graduate nurses who are harder to reach

Optimization of Collimator Jaw Locations for the LHC

A highly effective collimation scheme is required in the LHC to limit heating of the vacuum chamber and superconducting magnets by protons either uncaptured at injection or scattered from the collision points. The proposed system would consist of one set of primary collimators followed by three sets of secondary collimators downstream to clean up protons scattered from the primaries. Each set of collimators would consist of four pairs of jaws - horizontal, vertical, and 45 o and 135 o skew. A study is reported of the optimization of the longitudinal positions of these jaws with the aim of minimizing the maximum betatron amplitudes of protons surviving the collimation system. This is performed using an analytical representation of the action of the jaws and is confirmed by tracking. Significant improvement can be obtained by omitting inactive jaws and adding skew jaws

Numerical Optimization of Collimator Jaw Orientations and Locations in the LHC

The collimation system of LHC will consist of flat collimator jaws distributed along the IR7 lattice with the aim of limiting the maximum combined amplitudes of secondary halo particles (born along the edges of the primary collimators). The code DJ (Distribution of Jaws) computes this amplitude using a quasi-analytic algorithm (no tracking), by which the maximum initial angles are found, corresponding to trajectories escaping all secondary jaws. We report the latest version of DJ, which contains the following enhancements: (1) the orientation of each pair of jaws is a free variable (instead of using only vertical, horizontal, or 45 degrees skew jaws); (2) the minimizing method used is "simulated annealing", which, for our case of a discontinuous function of up to 32 variables, always finds a global minimum. Different initial jaw distributions lead to different final ones, but they all give essentially the same maximum halo amplitude; this seems to depend only on the number of jaws and the lattice parameters, particularly the tune-split. We discuss lattice characteristics found favorable for collimation

Initial error analysis for the LHC collimation insertion

The two cleaning insertions in the LHC, for betatron and momentum collimation, are optimized for an ideal lattice and collimator jaw setup. We have studied a collimation beam line with randomly generated jaw misalignments and quadrupole field and alignment errors, the resultant distortion of the reference orbit being corrected with the help of monitors placed near critical collimators. Different closed orbit errors and beam shapes are considered at the entrance. We report the level of errors for which no corrections are needed and the level for which corrections are not possible

A system to measure 3-directional relative displacements for a biomedical application

A micro system for measuring the relative displacements between a bone and an implant in a prosthetic hip of a human being has been realized. Novel are the small dimensions of the system combined with the possibility to measure relative displacements in three directions. The system consists of a microsensor body, a mechanical transducer element made by precision mechanics, electronics, and the final package. The realization and test results of a prototype system are presented. Typical ranges for these prototypes are ±500 μm for lateral directions and ±50 μm in axial direction

Fluctuation-dissipation theorem and flux noise in overdamped Josephson junction arrays

The form of the fluctuation-dissipation theorem for a resistively shunted Josephson juction array is derived with the help of the method which explicitely takes into acoount screening effects. This result is used to express the flux noise power spectrum in terms of frequency dependent sheet impedance of the array. The relation between noise amplitude and parameters of the detection coil is analysed for the simplest case of a single-loop coil.Comment: ReVTeX, 8 page

Collective pinning of a frozen vortex liquid in ultrathin superconducting YBa_2Cu_3O_7 films

The linear dynamic response of the two-dimensional (2D) vortex medium in ultrathin YBa_2Cu_3O_7 films was studied by measuring their ac sheet impedance Z over a broad range of frequencies \omega. With decreasing temperature the dissipative component of Z exhibits, at a temperature T*(\omega) well above the melting temperature of a 2D vortex crystal, a crossover from a thermally activated regime involving single vortices to a regime where the response has features consistent with a description in terms of a collectively pinned vortex manifold. This suggests the idea of a vortex liquid which, below T*(\omega), appears to be frozen at the time scales 1/\omega of the experiments.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Let

Ozone detection by differential absorption spectroscopy at ambient pressure with a 9.6μm pulsed quantum-cascade laser

We report direct absorption spectroscopic detection of ozone at ambient pressure with a pulsed, DFB quantum-cascade laser (QCL) tuned within 1044-1050cm-1 by temperature scanning. Wavelength calibration curves were derived from FTIR and CO2 spectra and interpreted with respect to the heat transfer from the heterostructure to the sink. The laser linewidth (∼0.13cm-1 FWHM) was found to decrease with temperature, probably as a result of operation at constant current. Spurious spectral features due to baseline inaccuracies were successfully filtered out from the QCL O3 spectra using differential absorption. Reference O3 concentrations were obtained by applying the same method to UV spectra, simultaneously measured with a differential optical absorption spectrometer (DOAS). Column densities retrieved from QCL spectra are in fairly good agreement (±20%) with the DOAS values above 28ppm m. The estimated QCL lowest detectable, absolute and differential absorptions, (7×10-3 and 2×10-3, respectively), entail effective detection limits of 14 and 25ppm m, respectively. Ongoing improvements in the acquisition system should allow the achievement of detection limits at the level of commercial open-path DOAS systems (∼2ppm m) in the near future. Our results demonstrate the applicability of the differential absorption method to QCL spectroscopy at ambient pressure, and encourage its use for open path detectio

THGEM operation in Ne and Ne/CH4

The operation of Thick Gaseous Electron Multipliers (THGEM) in Ne and Ne/CH4 mixtures, features high multiplication factors at relatively low operation potentials, in both single- and double-THGEM configurations. We present some systematic data measured with UV-photons and soft x-rays, in various Ne mixtures. It includes gain dependence on hole diameter and gas purity, photoelectron extraction efficiency from CsI photocathodes into the gas, long-term gain stability and pulse rise-time. Position resolution of a 100x100 mm^2 X-rays imaging detector is presented. Possible applications are discussed.Comment: Submitted to JINST, 25 pages, 33 figure