Characteristics of GaInNAsSb VCSELs operating near 1.55µm

A detailed study of the high-power pulsed operation of C-band optically-pumped GaInNAsSb vertical cavity surface emitting lasers is reported. The devices employ a resonant periodic gain structure grown by molecular beam epitaxy on a GaAs substrate with a 31-pair GaAs/AlAs bottom distributed Bragg reflector and a 4-λ, GaAs-based resonant cavity containing 10 GaInNAsSb quantum wells distributed among the 7 antinodes of the electric field. A dual-pump-band SiO2/TiO2 dielectric top mirror allows efficient optical pumping via low reflectivities at 808nm and 1064nm while providing very high reflectivity at the 1.55μm target emission wavelength. The laser characteristics were evaluated using both a Q-switched Nd:YAG 1064nm pump and a 20W-peak 180ns-pulsed 850nm diode laser. The importance of the gain-cavity detuning was evident from time-dependent spectral measurements of laser material subjected to post-growth annealing at different temperatures between 725 and 775°C. The highest annealing temperature produces the largest blue shift of the gain peak relative to the cavity resonance, resulting in the best power transfer characteristics as well as reduced temperature sensitivity

Physiotherapy practice in the private sector: organizational characteristics and models.

BACKGROUND: Even if a large proportion of physiotherapists work in the private sector worldwide, very little is known of the organizations within which they practice. Such knowledge is important to help understand contexts of practice and how they influence the quality of services and patient outcomes. The purpose of this study was to: 1) describe characteristics of organizations where physiotherapists practice in the private sector, and 2) explore the existence of a taxonomy of organizational models. METHODS: This was a cross-sectional quantitative survey of 236 randomly-selected physiotherapists. Participants completed a purpose-designed questionnaire online or by telephone, covering organizational vision, resources, structures and practices. Organizational characteristics were analyzed descriptively, while organizational models were identified by multiple correspondence analyses. RESULTS: Most organizations were for-profit (93.2%), located in urban areas (91.5%), and within buildings containing multiple businesses/organizations (76.7%). The majority included multiple providers (89.8%) from diverse professions, mainly physiotherapy assistants (68.7%), massage therapists (67.3%) and osteopaths (50.2%). Four organizational models were identified: 1) solo practice, 2) middle-scale multiprovider, 3) large-scale multiprovider and 4) mixed. CONCLUSIONS: The results of this study provide a detailed description of the organizations where physiotherapists practice, and highlight the importance of human resources in differentiating organizational models. Further research examining the influences of these organizational characteristics and models on outcomes such as physiotherapists' professional practices and patient outcomes are needed

Validation of the VUV-reflective coating for next-generation liquid xenon detectors

Coating detector materials with films highly reflective in the ultraviolet region improves sensitivity of the rare-event detectors that use liquid xenon. In this work, we investigate the MgF$_2$-Al-MgF$_2$ coating designed to achieve high reflectance at 175 nm, the mean wavelength of liquid xenon (LXe) scintillation. The coating was applied to an unpolished, passivated copper substrate mimicking a realistic detector component of the proposed nEXO experiment, as well as to two unpassivated substrates with "high" and "average" levels of polishing. After confirming the composition and morphology of the thin-film coating using TEM and EDS, the samples underwent reflectance measurements in LXe and gaseous nitrogen (GN2). Measurements in LXe exposed the coated samples to -100 $\deg$C for several hours. No peeling of the coatings was observed after several thermal cycles. Polishing is found to strongly correlate with the measured specular reflectance ($R_{\mathrm{spec}}$). In particular, 5.8(5)% specular spike reflectance in LXe was measured for the realistic sample at 20$\deg$ of incidence, while the values for similar angles of incidence on the high and average polish samples are 62.3(1.3)% and 27.4(7)%, respectively. At large angles (66\deg--75$\deg$), the $R_{\mathrm{spec}}$ in LXe for the three samples increases to 23(5)%, 80(8)%, and 84(18)%, respectively. The $R_{\mathrm{spec}}$ at around 45$\deg$ was measured in both GN2 and LXe for average polish sample and shows a reasonable agreement. Importantly, the total reflectance of the samples is comparable and estimated to be 92(8)%, 85(8)%, and 83(8)% in GN2 for the realistic, average, and high polish samples, respectively. This is considered satisfactory for the next-generation LXe experiments that could benefit from using reflective films, such as nEXO and DARWIN, thus validating the design of the coating.Comment: As accepted to JINS

Reciprocity as a foundation of financial economics

This paper argues that the subsistence of the fundamental theorem of contemporary financial mathematics is the ethical concept ‘reciprocity’. The argument is based on identifying an equivalence between the contemporary, and ostensibly ‘value neutral’, Fundamental Theory of Asset Pricing with theories of mathematical probability that emerged in the seventeenth century in the context of the ethical assessment of commercial contracts in a framework of Aristotelian ethics. This observation, the main claim of the paper, is justified on the basis of results from the Ultimatum Game and is analysed within a framework of Pragmatic philosophy. The analysis leads to the explanatory hypothesis that markets are centres of communicative action with reciprocity as a rule of discourse. The purpose of the paper is to reorientate financial economics to emphasise the objectives of cooperation and social cohesion and to this end, we offer specific policy advice

Storage of telecom wavelength heralded single photons in a fiber cavity quantum memory

We demonstrate the storage and retrieval of heralded single photons in a fiber-based cavity quantum memory. The photons are stored, and retrieved, from the memory using quantum frequency conversion which switches the photon into, and out of, resonance with the cavity. The photons, generated in the telecom O-band with a bandwidth of 81\,GHz, are retrieved from the memory with a $1/e$ lifetime of 1.64$\mu$s, or 32.8 cavity round trips. We show that non-classical photon statistics remain for 70 round trips. The internal memory efficiency after 0.5$\mu$s of storage is $10.9 \pm 0.5$%; a coupling efficiency of 60% into the memory cavity yields a total efficiency of $6.0\pm0.3$%. These results mark a crucial step forward in the development of fiber-based quantum memories, and high-bandwidth memories operating at telecom wavelengths, with applications to photon source multiplexing and fiber-based quantum networking.Comment: 9 pages, 4 figure

La preuve psychologique devant les tribunaux : barrières communicationnelles et épistémiques = Psychological evidence in court: communicational and epidemic barriers

Le présent article vise à documenter les défis liés à la communication entre décideurs judiciaires et psychologues experts, leurs rôles différents et besoins respectifs de même que les difficultés des psychologues experts à traduire les connaissances en psychologie au profit de meilleures décisions judiciaires. Trois concepts psychologiques seront examinés plus attentivement : la dangerosité, la capacité parentale et le meilleur intérêt de l’enfant. Nous rappellerons les besoins de formation spécialisée à la lumière des défis identifiés ainsi que l’importance d’une utilisation éthique des connaissances dans le domaine de la psychologie pour éclairer les tribunaux. The present article discusses some pitfalls in regards to the communication between legal decision makers and forensic psychologists, their respective roles and needs and the difficulty in translating psychological knowledge in the courtroom. Three psychological concepts will be discussed in greater detail: dangerousness, best interests of the child and parenting capacity. We underline the importance of specialized training in regard to the pitfalls discussed in this article and of an ethical use of the knowledge in psychology to assist the court

Rare-earth monosulfides as durable and efficient cold cathodes

In their rocksalt structure, rare-earth monosulfides offer a more stable alternative to alkali metals to attain low or negative electron affinity when deposited on various III-V and II-VI semiconductor surfaces. In this article, we first describe the successful deposition of Lanthanum Monosulfide via pulsed laser deposition on Si and MgO substrates and alumina templates. These thin films have been characterized by X-ray diffraction, atomic force microscopy, high resolution transmission electron microscopy, ellipsometry, Raman spectroscopy, ultraviolet photoelectron spectroscopy and Kelvin probe measurements. For both LaS/Si and LaS/MgO thin films, the effective work function of the submicron thick thin films was determined to be about 1 eV from field emission measurements using the Scanning Anode Field Emission Microscopy technique. The physical reasons for these highly desirable low work function properties were explained using a patchwork field emission model of the emitting surface. In this model, nanocrystals of low work function materials having a orientation perpendicular to the surface and outcropping it are surrounded by a matrix of amorphous materials with higher work function. To date, LaS thin films have been used successfully as cold cathode emitters with measured emitted current densities as high as 50 A/cm2. Finally, we describe the successful growth of LaS thin films on InP substrates and, more recently, the production of LaS nanoballs and nanoclusters using Pulsed Laser Ablation.Comment: 61 pages, 24 figure

Detection of Hepatitis E virus in swine using real-time RT-PCR

The zoonotic transmtsswn potential of Hepatitis E virus (HEY) is now widely recognized. Swine represents the main animal reservoir for this virus in many countries, including Canada. In recent years, different real-time RT-PCR assays were developed and proposed as reliable and sensitive detection methods. However, the quality of extracted RNA, presence of inhibitors and RN ase contamination of the samples may impact on the detection results obtained with these molecular methods. The aim of this study was to evaluate the use of a sample process control (SPC) within a real-time RT-PCR assay for the detection ofHEV. This TaqMan multiplex assay was afterwards used to evaluate the viral load ofHEV in organs, tissues and excreta of normal pigs at slaughter. HEY RNA was detected in at least one sample from 14 out of the 43 animals tested (32.6 %). HEV was present in lymph nodes (25.6%), bladder (23.3%), liver (20.9%), bile (18.6%), feces (13.9%), tonsils (7.0%) and plasma (2.3%) but was undetected in loins

Oceans and human health : navigating changes on Canada’s coasts

Ocean conditions can affect human health in a variety of ways that are often overlooked and unappreciated. Oceans adjacent to Canada are affected by many anthropogenic stressors, with implications for human health and well-being. Climate change further escalates these pressures and can expose coastal populations to unique health hazards and distressing conditions. However, current research efforts, education or training curriculums, and policies in Canada critically lack explicit consideration of these ocean–public health linkages. The objective of this paper is to present multiple disciplinary perspectives from academics and health practitioners to inform the development of future directions for research, capacity development, and policy and practice at the interface of oceans and human health in Canada. We synthesize major ocean and human health linkages in Canada, and identify climate-sensitive drivers of change, drawing attention to unique considerations in Canada. To support effective, sustained, and equitable collaborations at the nexus of oceans and human health, we recommend the need for progress in three critical areas: (i) holistic worldviews and perspectives, (ii) capacity development, and (iii) structural supports. Canada can play a key role in supporting the global community in addressing the health challenges of climate and ocean changes