In this paper we describe the motivation, challenges, and design methods of miniaturizing UV Index radiometry into a wearable form factor. The UV Index is the standard metric to measure instantaneous UV exposure in a way that is relevant to the human skin. However, unlike FDA regulated sensors like the glucose sensor, there is a currently an absence of specifications for the performance of wearable UV Index radiometers. In this paper, we develop performance metrics based on accuracy and sensitivity, and further evaluate the performance of several commercially available UV Index wearable radiometers on the basis of these metrics. Comparisons to laboratory-grade equipment show that the Shade radiometer is the most accurate and the most sensitive commercially available wearable UV radiometer. Ethics statement: This paper does not describe research involving human or animal subjects and is therefore not subject to review by IRB or IACUC.
Aux États-Unis, entre 1970 et 2000, l’Église catholique a affronté la montée en puissance des promoteurs de l’avortement, puis de l’euthanasie, en investissant sur le terrain de l’éducation et de l’information publique, des services aux personnes et de la mobilisation civique. Pour porter cet engagement moral et spirituel auprès des fidèles et de l’opinion, la Conférence épiscopale a voulu améliorer sa communication pastorale. Son Secrétariat pour les activités « pro-vie » a recouru à des professionnels des relations publiques pour « faire campagne ». Sont présentés ici le contexte, l’évolution et l’impact de cette collaboration qui signale une inculturation originale de la mission ecclésiale dans la rhétorique et l’apologétique de l’ère des médias et du marketing.
Abstract Sophisticated molecular machines have evolved in nature, and the first synthetic molecular machines have been demonstrated. With our increasing understanding of individual operating cycles, the question of how operation can be sustained over many cycles comes to the forefront. In the design of macroscale machines, performance and lifetime are opposing goals. Similarly, the natural evolution of biological nanomachines, such as myosin motor proteins, is likely constrained by lifetime requirements. Rather than bond rupture at high forces, bond fatigue under repeated small stresses may limit the mechanical performance of molecular machines. Here, the effect of cyclic stresses using single and double bonds as simple examples are discussed. Additionally, it is demonstrated that an increase in lifetime requires a reduction in mechanical load and that molecular engineering design features, such as polyvalent bonds capable of rebinding, can extend the bond lifetime dramatically. A universal scaling law for the force output of motors is extrapolated to the molecular scale to estimate the design space for molecular machines.
Apparus depuis le début des années 1990, les « jardins d’insertion » entendent conjuguer les visées du travail social (ou de lutte contre l’exclusion) et celles de l’agriculture (production généralement maraîchère et biologique). Mais quels collectifs de travail sont concrètement mis en place ? Comment les préoccupations environnementales sont-elles prises en compte par l’aide sociale ? Quelles compétences sont sollicitées chez les personnels encadrants ? Cet article cherche à comprendre non seulement comment l’activité agricole investit le travail social, mais aussi ce que fait le travail social à l’agriculture. En s’appuyant sur une démarche ethnographique (observation participante et entretiens semi-directifs) et comparative (deux structures comparables en France et aux États-Unis), il montre comment, selon le contexte, la mise en valeur dans l’accompagnement à l’insertion de visées agricoles et environnementales permet la reconnaissance de formes de savoir-faire et de trajectoires hybrides. L’accent mis sur les fonctions sociales de l’agriculture durable peut dans ces conditions permettre à de nouveaux profils professionnels d’émerger.
<p>The urbanisation leads to modifications in the water budget, not only at the surface but in groundwater as well. Few urban modelling studies deal with this topic, due to the lack of appropriate models. The URBS (Urban Runoff Branching Structure) model has been developed since several decades to simulate water transfers at the scale of an urban district. An integrated modelling approach is deliberately adopted to account for the numerous elements that influence urban hydrology: the spatial distribution of the sealed surfaces, interactions between the urban soil and water networks or underground, sustainable drainage systems&#8230;. In URBS, the spatial discretization of a catchment is based on Urban Hydrologic Elements (UHE) constituted by cadastral parcels and the adjacent streets, connected to the drainage network. URBS is able to perform continuous and long-period simulations (typically several years) of water fluxes in urban districts for small time-steps (typically few-minutes), with rainfall and potential evapotranspiration as input data.</p><p>The URBS model is adopted to study the hydrological impact of the Moulon district layout, a 200 ha development operation of the Paris-Saclay Cluster (currently underway). The project should result in an increase of sealed surfaces from 14% to 35% and a densification of underground constructions such as networks and basements. A shallow unconfined aquifer extends on the whole area. The fluctuations of ground-water levels have been monitored at an hourly time-step with 8 piezometers since 2012. Water-table levels exhibit significant variations, with near-saturation levels during winter and several meters depths during summer, although the piezometers do not all exhibit the same dynamics.</p><p>A calibration of the URBS model is first conducted for a 2-year period using only piezometric data and no flowrate data. The calibration is solely performed for the parameters influencing the soil compartment: soil permeability and parameters of the sewer infiltration process. Model performances are rather satisfactory with good representation of the observed levels for several piezometers, despite some difficulties for two piezometers exhibiting atypical variations. Once the URBS model is calibrated for the initial situation, simulations are conducted for the project layout (accounting for land-use modification and underground constructions) so as to evaluate the hydrological impacts of the development. Simulation results suggest that an increase of water table levels might be expected after the development of the district (this somehow surprising result may partly originate from the decrease of evapotranspiration fluxes associated with the increased of sealed surfaces).</p><p>The analysis of these first simulations also suggests that large uncertainties might be expected regarding the water levels computed by URBS. A simplified uncertainty analysis (based on Monte-Carlo simulations) is thus conducted to evaluate and distinguish uncertainties associated with model parameters and the total uncertainties in model outputs. While the results clearly evidence the importance of total uncertainties (although the uncertainties due to the model parameters remain low), they also confirm that groundwater depths could be reduced by the construction of the Moulon district.</p>
