Flatness enhancement of multi-wavelength Brillouin-Raman fiber laser with 10 GHz spacing utilizing Raman pump power distribution

A simple high flat amplitude multi-wavelength Brillouin-Raman fibre laser (MBRFL) with 10 GHz spacing and excellent optical signal-to-noise ratio (OSNR) in C-Band spectral region is demonstrated. The laser consists of a linear cavity in which 12 km dispersion compensating fiber (DCF) in addition to 49 cm Bismuth-oxide Erbium doped fiber (Bi-EDF) are employed as a gain medium for amplification. The impact of Raman pump power distribution through changes in coupling ratio on amplitude flatness is carried out by comparing the peak power discrepancy between odd- and even-order Brillouin Stoke lines. This is the main property that allows the efficient controlling of gain propagation between lasing lines that is vital for Stokes flattening initiation and other output spectra characteristics. The attainment of MBRFL with outstanding OSNR necessitates the utilizing of Bi-EDF as a noise suppressor. By utilizing a 50/50 coupler, 354 identical channels together with uniform Brillouin Stokes linewidth within only 0.3-dB maximum power difference between adjacent channels is generated. The average OSNR and Stokes power are 28 dB and -5 dBm respectively when the RPP is set at 1300 mW. To date, this is the highest flatness 10 GHz spacing MBRFL with outstanding OSNR attained in MBRFL that incorporate only a single Raman pump unit.

Few-cycle Yb laser source at 20 kHz using multidimensional solitary states in hollow-core fibers

We demonstrate ultrashort pulse compression from 300 fs down to 17 fs at a repetition rate of 20 kHz and 160-µJ output pulse energy (3.2 W of average power) using multidimensional solitary states (MDSS) in a 1-meter hollow-core fiber (HCF) filled with N₂O. Under static pressure, thermal limitations at this repetition rate annihilate the MDSS with suppression of spectral broadening. The results obtained in differential pressure configuration mitigate thermal effects and significantly increase the range of repetition rate over which MDSS can be used to compress sub-picosecond laser pulses.

Laser wakefield acceleration based x ray source using 225-TW and 13-fs laser pulses produced by thin film compression

We show that 13-fs laser pulses associated with 225 TW of peak power can be used to produce laser wakefield acceleration (LWFA) and generate synchrotron radiation. To achieve this, 130-TW high-power laser pulses (3.2 J, 24 fs) are efficiently compressed down to 13 fs with the thin film compression (TFC) technique using large chirped mirrors after propagation and spectral broadening through a 1-mm-thick fused silica plate. We show that the compressed 13-fs laser pulse can be properly focused even if it induces a 10% degradation of the Strehl ratio. We demonstrate the usability of such a laser beam. We observe both an increase of the electron energy and of the betatron radiation critical energy when the pulse duration is reduced to 13 fs compared with the 24-fs case.

70 mJ nonlinear compression and scaling route for an Yb amplifier using large-core hollow fibers

In this Letter, we investigate the energy-scaling rules of hollow-core fiber (HCF)-based nonlinear pulse propagation and compression merged with high-energy Yb-laser technology, in a regime where the effects such as plasma disturbance, optical damages, and setup size become important limiting parameters. As a demonstration, 70 mJ 230 fs pulses from a high-energy Yb laser amplifier were compressed down to 40 mJ 25 fs by using a 2.8-m-long stretched HCF with a core diameter of 1 mm, resulting in a record peak power of 1.3 TW. This work presents a critical advance of a high-energy pulse (hundreds of mJ level) nonlinear interactions platform based on high energy sub-ps Yb technology with considerable applications, including driving intense THz, X-ray pulses, Wakefield acceleration, parametric wave mixing and ultraviolet generation, and tunable long-wavelength generation via enhanced Raman scattering.

Characterizing the carrier-envelope phase stability of mid-infrared laser pulses by high harmonic generation in solids

We present a novel approach for measuring the carrier-envelope phase (CEP) stability of a laser source by employing the process of high harmonic generation (HHG) in solids. HHG in solids driven by few-cycle pulses is very sensitive to the waveform of the driving pulse, therefore enabling to track the shot-to-shot CEP fluctuations of a laser source. This strategy is particularly practical for pulses at long central wavelength up to the mid-infrared spectral range where usual techniques used in the visible or near-infrared regions are challenging to transpose. We experimentally demonstrate this novel tool by measuring the CEP fluctuations of a mid-infrared laser source centered at 9.5~μm.

High energy redshifted and enhanced spectral broadening by molecular alignment

We demonstrate an efficient approach for enhancing the spectral broadening of long laser pulses and for efficient frequency redshifting by exploiting the intrinsic temporal properties of molecular alignment inside a gas-filled hollow-core fiber (HCF). We find that laser-induced alignment with durations comparable to the characteristic rotational time scale TRotAlign enhances the efficiency of redshifted spectral broadening compared to noble gases. The applicability of this approach to Yb lasers with (few hundred femtoseconds) long pulse duration is illustrated, for which efficient broadening based on conventional Kerr nonlinearity is challenging to achieve. Furthermore, this approach proposes a practical solution for high energy broadband long-wavelength light sources, and it is attractive for many strong field applications.

High-field mid-infrared pulses derived from frequency domain optical parametric amplification

We present a novel, to the best of our knowledge, approach for scaling the peak power of mid-infrared laser pulses with few-cycle duration and carrier-to-envelope phase stabilization. Using frequency domain optical parametric amplification (FOPA), selective amplification is performed on two spectral slices of broadband pulses centered at 1.8 µm wavelength. In addition to amplification, the Fourier plane is used for specific pulse shaping to control both the relative polarization and the phase/delay between the two spectral slices of the input pulses. At the output of the FOPA, intrapulse difference frequency generation provides carrier-envelope phase stabilized two-cycle pulses centered at 9.5 µm wavelength with 25.5 µJ pulse energy. The control of the carrier-envelope phase is demonstrated through the dependence of high-harmonic generation in solids. This architecture is perfectly adapted to be scaled in the future to high average and high peak powers using picosecond ytterbium laser technologies.

Phase-matching-free pulse retrieval based on transient absorption in solids

In this paper, we introduce a pulse characterization technique that is free of phase-matching constraints, exploiting transient absorption in solids as an ultrafast optical switch. Based on a pump-probe setup, this technique uses pump pulses of sufficient intensity to induce the switch, while the pulses to characterize are probing the transmissivity drop of the photoexcited material. This enables the characterization of low-intensity ultra-broadband pulses at the detection limit of the spectrometer and within the transparency range of the solid. For example, by using zinc selenide (ZnSe), pulses with wavelengths from 0.5 to 20 μm can be characterized, denoting five octaves of spectral range. Using ptychography, we retrieve the temporal profiles of both the probe pulse and the switch. To demonstrate this approach, we measure ultrashort pulses from a titanium-sapphire (Ti-Sa) amplifier, which are compressed using a hollow core fiber setup, as well as infrared to mid-infrared pulses generated from an optical parametric amplifier (OPA). The characterized pulses are centered at wavelengths of 0.77, 1.53, 1.75, 4, and 10 μm, down to sub-two optical cycles duration, exceeding an octave of bandwidth, and with energy as low as a few nanojoules.

Targeting ethical considerations tied to image-based mobile health diagnostic support specific to clinicians in low-resource settings: the Brocher proposition

Background: mHealth applications assist workflow, help move towards equitable access to care, and facilitate care delivery. They have great potential to impact care in low-resource countries, but have significant ethical concerns pertaining to patient autonomy, safety, and justice. Objective: To achieve consensus among stakeholders on how to address concerns pertaining to autonomy, safety, and justice among mHealth developers and users in low-resource settings, in particular for the application of image-based consultation for diagnostic support. Methods: A consensus approach was taken during a three-day workshop using a purposive sample of global mHealth stakeholders (n = 27) professionally and geographically spread. Throughout a series of introductory talks, group brainstorming, plenary reviews, and synthesis by the moderators, lists of actions were generated that address the concerns engendered by mHealth applications on autonomy, justice and safety, taking into account the development, implementation, and scale-up phases of an mHealth application lifecycle. Results: Several types of actions were recommended; key ones among them included building in risk mitigation measures from the development stage, establishing inclusive consultation processes, using open sources platform whenever possible, training all clinical users, and bearing in mind that the gold standard of care is face-to-face consultation with the patient. Recommendations of patient, community and health system participation and of governance were identified as cutting across the mHealth lifecycle. Conclusion: Priorities agreed-upon at the meeting echo those put forward concerning other domains and locations of application of mHealth. Those more forcefully articulated are the need to adopt and maintain participatory processes as well as promoting self-governance. They are expected to cut across the mHealth lifecycle and are prerequisites to the safeguard of autonomy, safety and justice.

Assessing Shared Decision-Making Clinical Behaviors Among Genetic Counsellors

Shared decision-making (SDM) is a collaborative approach in which clinicians educate, support, and guide patients as they make informed, value-congruent decisions. SDM improves patients' health-related outcomes through increasing knowledge, reducing decisional conflict, and enhancing experience of care. We measured SDM in genetic counselling appointments with 27 pregnant women who were at increased risk to have a baby with a genetic abnormality. The eight experienced genetic counsellors who participated had no specific SDM training and were unaware that SDM was being assessed. Audio transcripts of appointments were scored using 'Observing Patient Involvement in Decision Making' (OPTION12). Patients' anxiety and decisional conflict were also assessed. The genetic counsellors' mean OPTION12 score was 42.4% (SD 9.0%; possible range 0-100%). Specific SDM behaviours that scored highest included introducing the concept of equipoise and listing all options with their pros and cons. Behaviours that scored lowest included eliciting patients' preferred approach to receiving information and desired degree of involvement in decision-making. Patients' levels of anxiety and decisional conflict were unassociated with genetic counsellors' OPTION12 scores. Some SDM behaviours were better demonstrated in this prenatal genetic counselling study than others. Formal training of genetic counsellors in SDM may enhance use of this approach in their professional practice.

Harmonic Generation from Neutral Manganese Atoms in the Vicinity of the Giant Autoionization Resonance

High harmonics from laser-ablated plumes are mostly generated from ionic species. We demonstrate that with ultrashort infrared (∼1.82  μm) driving lasers, high harmonics from laser-ablated manganese are predominantly generated from neutral atoms, a transition metal atom with an ionization potential of 7.4 eV. Our results open the possibility to advance laser-ablation technique to study the dynamics of neutral atoms of low ionization potential. Moreover, as manganese contains giant autoionizing resonance, intense and broadband high harmonics have been demonstrated from this resonance at energies from 49 to 53 eV. This opens the possibility to generate intense attosecond pulses directly from the giant resonances, as well as to study these resonances using high-harmonic spectroscopy.

Time-resolved nuclear dynamics in bound and dissociating acetylene

We have investigated nuclear dynamics in bound and dissociating acetylene molecular ions in a time-resolved reaction microscopy experiment with a pair of few-cycle pulses. Vibrating bound acetylene cations or dissociating dications are produced by the first pulse. The second pulse probes the nuclear dynamics by ionization to higher charge states and Coulomb explosion of the molecule. For the bound cations, we observed vibrations in acetylene (HCCH) and its isomer vinylidene (CCHH) along the CC-bond with a periodicity of around 26 fs. For dissociating dication molecules, a clear indication of enhanced ionization is found to occur along the CH- and CC-bonds after 10 fs to 40 fs. The time-dependent ionization processes are simulated using semi-classical on-the-fly dynamics revealing the underling mechanisms.

High-order harmonic generation from the dressed autoionizing states

In high-order harmonic generation, resonant harmonics (RH) are sources of intense, coherent extreme-ultraviolet radiation. However, intensity enhancement of RH only occurs for a single harmonic order, making it challenging to generate short attosecond pulses. Moreover, the mechanism involved behind such RH was circumstantial, because of the lack of direct experimental proofs. Here, we demonstrate the exact quantum paths that electron follows for RH generation using tin, showing that it involves not only the autoionizing state, but also a harmonic generation from dressed-AIS that appears as two coherent satellite harmonics at frequencies ±2Ω from the RH (Ω represents laser frequency). Our observations of harmonic emission from dressed states open the possibilities of generating intense and broadband attosecond pulses, thus contributing to future applications in attosecond science, as well as the perspective of studying the femtosecond and attosecond dynamics of autoionizing states.

High-energy photons in XUV range and attosecond pulses are generated from infrared laser pulses through high harmonic generation in gases and solids. Here, the authors demonstrate the microscopic origin of resonant harmonic generation involving the autoionizing states of Sn in plasma plumes.

Role of Excited States In High-order Harmonic Generation

We investigate the role of excited states in high-order harmonic generation by studying the spectral, spatial, and temporal characteristics of the radiation produced near the ionization threshold of argon by few-cycle laser pulses. We show that the population of excited states can lead either to direct extreme ultraviolet emission through free induction decay or to the generation of high-order harmonics through ionization from these states and recombination to the ground state. By using the attosecond lighthouse technique, we demonstrate that the high-harmonic emission from excited states is temporally delayed by a few femtoseconds compared to the usual harmonics, leading to a strong nonadiabatic spectral redshift.

Frequency domain tailoring for intra-pulse frequency mixing

Generating mid infrared (MIR) pulses by difference frequency generation (DFG) is often a trade-off between the maximum stability given by all-inline intra-pulse arrangements and the independent control of pulse parameters with inter-pulse pump-probe like scenarios. We propose a coalescence between both opposing approaches by realizing an all-inline inter-pulse DFG scheme employing a 4-f setup. This allows independent manipulation of the amplitude, delay and polarization of the two corresponding spectral side bands of a supercontinuum source while maintaining 20 attoseconds jitter without any feedback stabilization. After filamentation in air, the broadened Ti:Sa spectrum is tailored in a 4-f setup to generate tunable MIR pulses. In this manner, 2 µm, 4.8 µJ, 26.5 fs and carrier-envelope-phase (CEP) stabilized pulses are generated in a single DFG stage.

All-Optical Reconstruction of Crystal Band Structure

The band structure of matter determines its properties. In solids, it is typically mapped with angle-resolved photoemission spectroscopy, in which the momentum and the energy of incoherent electrons are independently measured. Sometimes, however, photoelectrons are difficult or impossible to detect. Here we demonstrate an all-optical technique to reconstruct momentum-dependent band gaps by exploiting the coherent motion of electron-hole pairs driven by intense midinfrared femtosecond laser pulses. Applying the method to experimental data for a semiconductor ZnO crystal, we identify the split-off valence band as making the greatest contribution to tunneling to the conduction band. Our new band structure measurement technique is intrinsically bulk sensitive, does not require a vacuum, and has high temporal resolution, making it suitable to study reactions at ambient conditions, matter under extreme pressures, and ultrafast transient modifications to band structures.

Determinants of Physicians' Intention to Collect Data Exhaustively in Registries: an Exploratory Study in Bamako's Community Health Centres

BACKGROUND

The incomplete collection of health data is a prevalent problem in healthcare systems around the world, especially in developing countries. Missing data hinders progress in population health and perpetuates inefficiencies in healthcare systems.

OBJECTIVE

This study aims to identify the factors that predict the intention of physicians practicing in community health centres of Bamako, Mali, to collect data exhaustively in medical registries.

DESIGN

A cross sectional study.

METHOD

In January and February 2011, we conducted a study with a random sample of thirty two physicians practicing in community health centres of Bamako, using a questionnaire. Data was analyzed by using descriptive statistics, correlations and linear regression.

MAIN OUTCOMES MEASURES

Trained investigators administered a questionnaire measuring physicians' sociodemographic and professional characteristics as well as constructs from the Theory of Planned Behaviour.

RESULTS

Our results showed that physicians' intention to collect data exhaustively is influenced by subjective norms and by the physician's number of years in practice.

CONCLUSIONS

the results of this study could be used as a guide for health workers and decision makers to improve the quality of health information collected in community health centers.

Linking high harmonics from gases and solids

When intense light interacts with an atomic gas, recollision between an ionizing electron and its parent ion creates high-order harmonics of the fundamental laser frequency. This sub-cycle effect generates coherent soft X-rays and attosecond pulses, and provides a means to image molecular orbitals. Recently, high harmonics have been generated from bulk crystals, but what mechanism dominates the emission remains uncertain. To resolve this issue, we adapt measurement methods from gas-phase research to solid zinc oxide driven by mid-infrared laser fields of 0.25 volts per ångström. We find that when we alter the generation process with a second-harmonic beam, the modified harmonic spectrum bears the signature of a generalized recollision between an electron and its associated hole. In addition, we find that solid-state high harmonics are perturbed by fields so weak that they are present in conventional electronic circuits, thus opening a route to integrate electronics with attosecond and high-harmonic technology. Future experiments will permit the band structure of a solid to be tomographically reconstructed.

Shared decision making: really putting patients at the centre of healthcare

Although many clinicians feel they already use shared decision making, research shows a perception-reality gap. A M Stiggelbout and colleagues discuss why it is important and highlight some best practices.

Damage initiation and progression in the cartilage surface probed by nonlinear optical microscopy

With increasing interest in treating osteoarthritis at its earliest stages, it has become important to understand the mechanisms by which the disease progresses across a joint. Here, second harmonic generation (SHG) microscopy, coupled with a two-dimensional spring-mass network model, was used to image and investigate the collagen meshwork architecture at the cartilage surface surrounding osteoarthritic lesions. We found that minor weakening of the collagen meshwork leads to the bundling of fibrils at the surface under normal loading. This bundling appears to be an irreversible step in the degradation process, as the stress concentrations drive the progression of damage, forming larger bundles and cracks that eventually form lesions.

Second harmonic generation in AlGaAs photonic wires using low power continuous wave light

We report modal phase matched (MPM) second harmonic generation (SHG) in high-index contrast AlGaAs sub-micron ridge waveguides, by way of sub-mW continuous wave powers at telecommunication wavelengths. We achieve an experimental normalized conversion efficiency of ~14%/W/cm2, obtained through a careful sub-wavelength design supporting both the phase matching requirement and a significant overlap efficiency. Furthermore, the weak anomalous dispersion, robust fabrication technology and possible geometrical and thermal tuning of the device functionality enable a fully integrated multi-functional chip for several critical areas in telecommunications, including wavelength (time) division multiplexing and quantum entanglement.

Surface ablation of corneal stroma with few-cycle laser pulses at 800 nm

We report measurements of crater diameter and surface ablation threshold as a function of laser fluence in porcine corneal stroma and fused silica with pulse durations of 7 fs (2.7 optical cycles), 30 fs and 100 fs at 800 nm. For laser pulses with Gaussian radial intensity profile, we show experimentally that the square of the crater diameter is a linear function of the logarithm of the fluence in fused silica, while it is closer to a linear function of the fluence in corneal stroma. Extrapolating these relations to zero diameter indicates that for both media the minimum fluence required for surface ablation is reduced with shorter pulse duration. A simple theoretical model suggests that this effect is due to a more significant contribution of photoionization as the laser pulse duration shortens.

A systematic review of interventions promoting clinical information retrieval technology (CIRT) adoption by healthcare professionals

PURPOSE

This paper presents the evidence on the effectiveness of interventions promoting the use of clinical information retrieval technologies (CIRTs) by healthcare professionals.

METHODS

We electronically searched articles published between January 1990 and March 2008 using following inclusion criteria: (1) participants were healthcare professionals; (2) specific intervention promoted CIRT adoption; (3) studies were randomised controlled trials, controlled clinical trials, controlled before and after studies or interrupted time series analyses; and (4) they objectively reporting measured outcomes on CIRT use.

RESULTS

We found nine studies focusing on CIRT use. Main outcomes measured were searching skills and/or frequency of use of electronic databases by healthcare professionals. Three studies reported a positive effect of the intervention on CIRT use, one showed a positive impact post-intervention, and four studies failed to demonstrate significant intervention effect. The ninth study examined financial disincentives, and found a significant negative effect of introducing user fees for searching MEDLINE in clinical settings. A meta-analysis showed that educational meetings were the only type of interventions reporting consistent positive effects on CIRT adoption.

CONCLUSION

CIRT is an information and communication technology commonly used in healthcare settings. Interventions promoting CIRT adoption by healthcare professionals have shown some success in improving searching skills and use of electronic databases. However, the effectiveness of these interventions remains uncertain and more rigorous studies are needed.

Wavelength scaling of high harmonic generation efficiency

Using longer wavelength laser drivers for high harmonic generation is desirable because the highest extreme ultraviolet frequency scales as the square of the wavelength. Recent numerical studies predict that high harmonic efficiency falls dramatically with increasing wavelength, with a very unfavorable lambda(-(5-6)) scaling. We performed an experimental study of the high harmonic yield over a wavelength range of 800-1850 nm. A thin gas jet was employed to minimize phase matching effects, and the laser intensity and focal spot size were kept constant as the wavelength was changed. Ion yield was simultaneously measured so that the total number of emitting atoms was known. We found that the scaling at constant laser intensity is lambda(-6.3+/-1.1) in Xe and lambda(-6.5+/-1.1) in Kr over the wavelength range of 800-1850 nm, somewhat worse than the theoretical predictions.

The effects of flaxseed dietary supplement on lipid profile, bone mineral density, and symptoms in menopausal women: a randomized, double-blind, wheat germ placebo-controlled clinical trial

Phytoestrogens are increasingly incorporated into the diet of menopausal women. However, there are limited data on the efficacy of flaxseed on the consequences of estrogen deficiency in menopausal women. The purpose of the study was to assess the effects of flaxseed incorporation into the diet of healthy menopausal women. One hundred and ninety-nine menopausal women were randomly assigned to consume 40 g flaxseed/d (n = 101) or wheat germ placebo (n = 98) for 12 months. At baseline and at month 12, serum levels of lipids, bone mineral density (BMD), and menopausal symptoms were evaluated. Statistical analysis was performed under the intention to treat principle. Flaxseed reduced serum total (-0.20 +/- 0.51 mmol/liter; P = 0.012) and high-density lipoprotein (-0.08 +/- 0.24 mmol/liter; P = 0.031) cholesterol concentrations compared with wheat germ placebo. BMD did not differ significantly between the two arms. Both flaxseed and wheat germ reduced (P < 0.0001) the severity scores of menopausal symptoms, but no statistical difference was found between the two arms. Our findings suggest that 1-yr incorporation of flaxseed into the diet produced a favorable, but not clinically significant, effect on blood cholesterol and caused no significant change in BMD or symptoms in healthy menopausal women.

Shakeup excitation during optical tunnel ionization

Shakeup of a two-electron system is investigated in the strong infrared laser field limit, both theoretically and experimentally. During tunnel ionization the electron shakes up a second electron to an excited bound state. Theoretically, a complete analytical theory of shakeup in intense laser fields is developed. We predict that shakeup produces one excited sigma(u) D(+)(2) state in approximately 10(5) ionization events. Shakeup is measured experimentally by using the molecular clock provided by the internuclear motion. The number of measured events is found to be in excellent agreement with theory.

Time-resolved double ionization with few cycle laser pulses

Ionization of D2 launches a vibrational wave packet on the ground state of D+2. Removal of the second electron places a pair of D+ ions onto a Coulombic potential. Measuring the D+ kinetic energy determines the time delay between the first and the second ionization. Caught between a falling ionization and a rapidly rising intensity, the typical lifetime of the D+2 intermediate is less than 5 fs when an intense 8.6 fs laser pulse is used. We simulate Coulomb explosion imaging of the ground state wave function of D2 by a 4 fs optical pulse and compare with our experimental observations.

Probing molecular dynamics with attosecond resolution using correlated wave packet pairs

Spectroscopic measurements with increasingly higher time resolution are generally thought to require increasingly shorter laser pulses, as illustrated by the recent monitoring of the decay of core-excited krypton using attosecond photon pulses. However, an alternative approach to probing ultrafast dynamic processes might be provided by entanglement, which has improved the precision of quantum optical measurements. Here we use this approach to observe the motion of a D2+ vibrational wave packet formed during the multiphoton ionization of D2 over several femtoseconds with a precision of about 200 attoseconds and 0.05 ångströms, by exploiting the correlation between the electronic and nuclear wave packets formed during the ionization event. An intense infrared laser field drives the electron wave packet, and electron recollision probes the nuclear motion. Our results show that laser pulse duration need not limit the time resolution of a spectroscopic measurement, provided the process studied involves the formation of correlated wave packets, one of which can be controlled; spatial resolution is likewise not limited to the focal spot size or laser wavelength.

Sub-laser-cycle electron pulses for probing molecular dynamics

Experience shows that the ability to make measurements in any new time regime opens new areas of science. Currently, experimental probes for the attosecond time regime (10(-18) 10(-15) s) are being established. The leading approach is the generation of attosecond optical pulses by ionizing atoms with intense laser pulses. This nonlinear process leads to the production of high harmonics during collisions between electrons and the ionized atoms. The underlying mechanism implies control of energetic electrons with attosecond precision. We propose that the electrons themselves can be exploited for ultrafast measurements. We use a 'molecular clock', based on a vibrational wave packet in H(2)(+) to show that distinct bunches of electrons appear during electron ion collisions with high current densities, and durations of about 1 femtosecond (10(-15) s). Furthermore, we use the molecular clock to study the dynamics of non-sequential double ionization.

[Evaluation of medical web sites. Interobserver and intraobserver reliability of an evaluation tool]

OBJECTIVE

To develop and test the reliability of a tool for rating websites that provide information on evidence-based medicine.

DESIGN

For each site, 60% of the score was given for content (eight criteria) and 40% was given for organization and presentation (nine criteria). Five of 10 randomly selected sites met the inclusion criteria and were used by three observers to test the accuracy of the tool. Each site was rated twice by each observer, with a 3-week interval between ratings.

SETTING

Laval University, Quebec city.

PARTICIPANTS

Three observers.

MAIN OUTCOME MEASURES

The intraclass correlation coefficient (ICC) was used to rate the reliability of the tool.

RESULTS

Average overall scores for the five sites were 40%, 79%, 83%, 88%, and 89%. All three observers rated the same two sites in fourth and fifth place and gave the top three ratings to the other three sites. The overall rating of the five sites by the three observers yielded an ICC of 0.93 to 0.97. An ICC of 0.87 was obtained for the two overall ratings conducted 3 weeks apart.

CONCLUSION

This new tool offers excellent intraobserver and interobserver measurement reliability and is an excellent means of distinguishing between medical websites of varying quality. For best results, we recommend that the tool be used simultaneously by two observers and that differences be resolved by consensus.

[Making a decision about hormone replacement therapy. A randomized controlled trial]

OBJECTIVE

To compare the efficacy of a decision-making aid with an information document from the Society of Obstetricians and Gynaecologists of Canada (SOGC) with regard to decisions about hormone replacement therapy (HRT).

DESIGN

Randomized clinical trial.

SETTING

Quebec city region.

PARTICIPANTS

Menopausal Francophone women 45 to 69 years old.

INTERVENTIONS

Subjects were given a manual and an audiocassette describing a six-step approach to making a decision about HRT.

MAIN OUTCOME MEASURES

Amount of anxiety over the decision (main outcome), general knowledge of the risks and benefits of HRT, personal expectations and values concerning these risks and benefits, and women's views on HRT.

RESULTS

Anxiety levels were significantly reduced in both groups, but the difference between the effectiveness of the two interventions was not significant (P = .77). Percentages of women whose general knowledge increased and of women with realistic expectations were significantly higher in the experimental group (P < .003 and P < .0001, respectively). Congruence between personal values and decisions about HRT increased significantly more in the experimental group (P < or = .003).

CONCLUSION

The six-step approach to decision making was more helpful than the SOGC's information document in increasing subjects' knowledge of the risks and benefits of HRT, in creating more realistic expectations of HRT, and in increasing the congruence between subjects' personal values and their decisions on HRT.

[Rally-resources. The integration of community principles]

PROBLEM BEING ADDRESSED

Family medicine training programs are required to teach the four principles of family medicine, two of which deal with community responsibilities. Teachers in the Family Practice Unit at the Centre hospitalier de Québec, pavillon St-François d'Assise (UMF-SFA) have developed a learning activity that introduces residents to community agencies in the area.

OBJECTIVE OF PROGRAM

To introduce family medicine residents to community aspects of the principles of family medicine, to help them identify community resources in the area served by UMF-SFA, to discuss these services so that they can use them effectively, and to offer new residents an opportunity to become better acquainted with these services and with the UMF-SFA team.

MAIN COMPONENTS OF PROGRAM

In early September, a half-day is set aside for a rally during which mixed teams of supervisors and residents (four to eight to a team) visit about 10 community agencies in the vicinity of UMF-SFA. Walking from place to place, the teams spend 15 to 20 minutes with staff or users of each agency. The informal tone of the rally makes it easier for residents to understand these agencies.

CONCLUSION

Each year for the past 10 years, all UMF-SFA members have taken part in a rally that introduces residents to the community-based resources of family medicine.

Determinants of the intention to adopt hormone replacement therapy among premenopausal women

OBJECTIVE

To identify the psychosocial factors that influence the intention to adopt hormone replacement therapy (HRT) at menopause.

METHODS

Random Digit Dialing was used to recruit 644 premenopausal non-hysterectomized women aged 45-54. Data were collected using a telephone questionnaire previously developed according to the theory of planned behaviour. Variables measured were: intention to adopt HRT (INT); attitude towards HRT (Aact); perceived social norm (SN); perceived behavioural control (PBC); and personal normative belief (PNB). Socio-demographic data were also obtained.

RESULTS

Stepwise multiple regression of INT on the theoretical variables yielded an R(2) of 0.70. The determinants were Aact (beta=0.39, P<0.001), PNB (beta=0.25, P<0.001), PBC (beta=0.23, P<0.001) and SN (beta=0.12, P<0.001). Women with a strong intention to adopt HRT represented 25% of the sample. These women were more likely to believe that adopting HRT would have the following positive consequences: an improvement in general well-being, the prevention of health problems, an improvement in interpersonal relationships, an increase in productivity, the regulation of mood swings and a reduction of hot flashes. They were also more likely to believe in the following negative consequences: side-effects, an increased risk of cancer, the likelihood of weight gain, and interference in the natural course of menopause (all at P<0.001).

CONCLUSION

Actions that target behaviourial beliefs regarding HRT and perceived barriers to its adoption are most likely to influence adoption of HRT.

[Recurrence and satisfaction levels following onysectomy with or without phenolization]

OBJECTIVE

To compare recurrence and satisfaction levels among patients undergoing onysectomy with phenolization (OP) and without phenolization (OS).

DESIGN

Retrospective cohort study.

SETTING

Family practice unit.

PARTICIPANTS

All patients (N = 35) undergoing onysectomy between September 1992 and May 1993, and between January 1996 and February 1997.

MAIN OUTCOME MEASURES

Type of onysectomy (OP or OS) was taken from the patient's medical record. A telephone interview was used to determine whether patients had experienced recurrence; satisfaction was measured retrospectively at diagnosis, at time of surgery, and after surgery using a five-point scale (very unsatisfied to very satisfied).

RESULTS

Among the 30 patients interviewed by telephone, four of the six patients in the OS group experienced recurrence, and four of the 24 patients in the OP group experienced recurrence. (Fisher's exact test, P = .007). In the OS group, satisfaction levels at diagnosis, during surgery, and after surgery were 4.7, 4.5, and 4.2, respectively. In the OP group, satisfaction levels at these three points were 4.3, 4.2, and 4.4, respectively. Notwithstanding technique used, a connection was noted between recurrence and satisfaction level at the time of the telephone interview (repeated measures test, P = .036).

CONCLUSION

In general medicine, onysectomy with phenolization could be the treatment of choice for ingrown toenails.

[Factors influencing the adoption of hormone replacement therapy]

OBJECTIVE

To develop and test the metrologic qualities of a questionnaire for a survey on determining factors in initiating hormone replacement therapy (HRT), using Ajzen's planned behaviour theory.

DESIGN

Semistructured interviews to collect the behavioural beliefs needed to develop the questionnaire and the test-retest.

SETTING

Family medicine practices and the community.

PARTICIPANTS

In two family medicine practices, 42 women completed semistructured interviews that yielded the beliefs needed to design the questionnaire for the core survey. Thirty other women from the community took part in the test-retest 2 weeks later.

MAIN OUTCOME MEASURES

The internal consistency of the constructs (tendency of answers within a group of questions) was determined using Cronbach's alpha coefficient. Stability of the global constructs (proportion of subjects who had an absolute difference in their scores of less than 1 between the two measurements) was determined using the adjusted agreement coefficient (adjusted Po).

RESULTS

Findings for 12 of the 14 global constructs were above the acceptance threshold of 0.60. In one case alpha could not be measured because there was only one question for measuring it. On the test-retest, 12 of the 14 adjusted Pos had a reliability rating at or above 80%.

CONCLUSION

The questionnaire developed using Ajzen's planned behaviour theory had the requisite metrologic qualities for integration into the core survey on determining factors for initiating HRT.