10-W-level monolithic dysprosium-doped fiber laser at 3.24 μm

We report, to the best of our knowledge, the first entirely monolithic dysprosium (Dy)-doped fluoride fiber laser operating in the mid-IR region. The system delivers 10.1 W at 3.24 μm in continuous operation, a record for fiber oscillators in this range of wavelengths. The Dy3+ fiber is pumped in-band using an erbium-doped fiber laser at 2.83 μm made in-house and connected through a fusion splice. Two fiber Bragg gratings directly written in the Dy-doped fiber form the 3.24 μm laser cavity to provide a spectrally controlled laser output. This substantial increase of output power in the 3.0 3.3 μm spectral range–could open new possibilities for applications in spec-troscopy and advanced manufacturing

What can designing learning-by-concordance clinical reasoning cases teach us about instruction in the health sciences?

Introduction: Learning-by-concordance (LbC) is an online learning strategy to practice reasoning skills in clinical situations. Writing LbC clinical cases, comprising an initial hypothesis and supplementary data, differs from typical instructional design. We sought to gain a deeper understanding from experienced LbC designers to better support clinician educators’ broader uptake of LbC. Methods: A dialogic action research approach was selected because it yields triangulated data from a heterogeneous group. We conducted three 90-minute dialogue-group sessions with eight clinical educators. Discussions focused on the challenges and pitfalls of each LbC design stage described in the literature. Recordings were transcribed and analyzed thematically. Results: We identified three themes by thematic analysis about the challenges inherent in designing LbC that are unique for this type of learning strategy: 1) the distinction between pedagogical intent and learning outcome; 2) the contextual cues used to challenge students and advance their learning and 3) the integration of experiential with formalized knowledge for cognitive apprenticeship. Discussion: A clinical situation can be experienced and conceptualized in many ways, and multiple responses are appropriate. LbC designers use contextual cues from their experience and combine them with formalized knowledge and protocols to write effective LbC clinical reasoning cases. LbC focuses learners’ attention on decision-making in grey areas that characterize the nature of professional clinical work. This in-depth study on LbC design, indicating the integration of experiential knowledge, might call for new thinking about instructional design

Effects of Vertical Spatial Overlap on Phytoplankton Diversity under Experimentally Altered Lake Stratification Regimes

In phytoplankton communities, competitive exclusion might occur when functionally similar species are impeded from regulating their positions along light and nutrient gradients to reduce niche overlap. Greater spatial overlap (SO) between species due to water column mixing could thus promote competitive exclusion, reducing community taxonomic diversity. However, greater SO could also promote coexistence of functionally different taxa. Using data from a whole-lake experiment, we investigated the effects of SO and other relevant environmental factors on phytoplankton diversity across the water columns of lake basins with different thermocline manipulations. We estimated SO using an in situ fluorometer, and overall community diversity microscopically. Using structured equation models, we estimated directional relationships between phytoplankton diversity, SO, the lake physical structure and the zooplankton community. No significant effect of SO on phytoplankton taxonomic diversity was observed, but higher SO was associated with greater functional diversity. Change in lake physical structure and in the zooplankton community also affected diversity, with a negative response to increased top-down interactions. Overall, despite the fact that the alteration of water column stratification structure and top-down interactions were stronger drivers of phytoplankton diversity in our system, some effect of spatial overlap on the outcome of inferred competitive interactions were observable

The Epworth Sleepiness Scale: Self-Administration Versus Administration by the Physician, and Validation of a French Version

BACKGROUND/OBJECTIVES: The Epworth Sleepiness Scale (ESS) measures sleepiness and is used for, among others, patients with obstructive sleep apnea (OSA). The questionnaire is usually self-administered, but may be physician administered. The aim was to compare the two methods of administration and to validate a French version

Diode-pumped mid-infrared fiber laser with 50% slope efficiency

Until now, the field of mid-infrared fiber laser research has been constrained by the limitation imposed by the Stokes efficiency limit. The conversion of high-power diode light emission operating at near-infrared wavelengths into mid-infrared light invariably results in the deposition of significant amounts of heat in the fiber. This issue is compounded by the fact that mid-infrared transmitting glasses are thermomechanically weak, which means scaling the output power has been a longstanding challenge. In this report, we show that by cascading the adjacent transitions of the erbium ion at 2.8 and 1.6 μm in combination with a low-loss fluoride fiber, the slope efficiency for emission at 2.8 μm can reach 50%, thus exceeding the Stokes limit by 15%. We also show that by highly resonating the 1.6 μm transition, a highly non-resonant excited-state absorption process efficiently recycles the excitation back to the upper laser level of the mid-infrared transition. This demonstration represents a significant advancement for the field that paves the way for future demonstrations that will exceed the 100 W power level.4 page(s

Bilan de carbone de prairies issues de déforestation en Amazonie française (Guyane)

Résumé + posterLe développement de l'élevage de ruminants et ses conséquences sur les changements climatiques font l'objet d'un débat mondial qui prend désormais en compte les services écologiques. La forte croissance de l’élevage en Amazonie depuis quelques décennies illustre parfaitement ces nouveaux défis où les productions animales s’inscrivent désormais dans le cadre des mesures d'atténuation des gaz à effet de serre (GES) d’un secteur fortement mis en cause pour ses émissions. En Guyane, la filière bovine viande (20 % de la consommation de viande) est particulièrement concernée par ces défis ; le doublement prévu de la population guyanaise d’ici 2030 implique un développement endogène du territoire pour répondre aux besoins alimentaires croissants. L’expansion en cours des systèmes herbagers éleveurs naisseurs (25 % de la Surface Agricole Utilisée) sur la forêt (92 % du territoire) doit être accompagnée par des recherches sur une gestion durable des pâturages conciliant production et services environnementaux. Les systèmes herbagers peuvent contribuer à la lutte contre le réchauffement climatique en augmentant le stockage du carbone (C) dans le sol et en diminuant les émissions des 3 principaux GES (gaz carbonique : CO2, méthane : CH4 et oxyde nitreux : N2O). L’objectif de notre étude est d’établir des bilans GES à l’échelle de la parcelle pâturée, par des mesures directes de flux de CO2 et de N2O et l’estimation des émissions de CH4