Technical Note: Quantification of interferences of wet chemical HONO LOPAP measurements under simulated polar conditions

In the present pilot study, an optimized LOPAP instrument (LOng Path Absorption Photometer) for the detection of nitrous acid (HONO) in the atmosphere (DL 0.2 pptV) was tested at the high alpine research station Jungfraujoch at 3580 m altitude in the Swiss Alps under conditions comparable to polar regions. HONO concentrations in the range <0.5–50 pptV with an average of 7.5 pptV were observed at the Jungfraujoch. The diurnal profiles obtained exhibited clear maxima at noon and minima with very low concentration during the night supporting the proposed photochemical production of HONO. In good agreement with recent measurements at the South Pole, it was demonstrated, that interferences of chemical HONO instruments can significantly influence the measurements and lead to considerable overestimations, especially for low pollution level. Accordingly, the active correction of interferences is of paramount importance for the determination of reliable HONO data

Technical Note: Quantification of interferences of wet chemical HONO measurements under simulated polar conditions

International audienceIn the present pilot study, an optimized LOPAP instrument for the detection of nitrous acid (HONO) in the atmosphere (DL 0.2 pptV) was tested at the high alpine research station "Jungfraujoch" at 3580 m altitude in the Swiss Alps under conditions comparable to polar regions. HONO concentrations in the range <0.5?50 pptV with an average of 7.5 pptV were observed at the "Jungfraujoch". The diurnal profiles obtained exhibited clear maxima at noon and minima with very low concentration during the night supporting the proposed photochemical production of HONO. In good agreement with recent measurements at the South Pole, it was demonstrated, that interferences of chemical HONO instruments can significantly influence the measurements and lead to considerable overestimations, especially for low pollution level. Accordingly, the correction of interferences is of paramount importance for those instruments, which sample HONO on aqueous or humid surfaces

Characterisation of the photolytic HONO-source in the atmosphere simulation chamber SAPHIR

HONO formation has been proposed as an important OH radical source in simulation chambers for more than two decades. Besides the heterogeneous HONO formation by the dark reaction of NO₂ and adsorbed water, a photolytic source has been proposed to explain the elevated reactivity in simulation chamber experiments. However, the mechanism of the photolytic process is not well understood so far. As expected, production of HONO and NO_x was also observed inside the new atmospheric simulation chamber SAPHIR under solar irradiation. This photolytic HONO and NO_x formation was studied with a sensitive HONO instrument under reproducible controlled conditions at atmospheric concentrations of other trace gases. It is shown that the photolytic HONO source in the SAPHIR chamber is not caused by NO₂ reactions and that it is the only direct NO_y source under illuminated conditions. In addition, the photolysis of nitrate which was recently postulated for the observed photolytic HONO formation on snow, ground, and glass surfaces, can be excluded in the chamber. A photolytic HONO source at the surface of the chamber is proposed which is strongly dependent on humidity, on light intensity, and on temperature. An empirical function describes these dependencies and reproduces the observed HONO formation rates to within 10%. It is shown that the photolysis of HONO represents the dominant radical source in the SAPHIR chamber for typical tropospheric O₃/H₂O concentrations. For these conditions, the HONO concentrations inside SAPHIR are similar to recent observations in ambient air

Logistikqualifikation und Gamification: Softwareentwicklung und Pilotierung der MARTINA-App

Logistics commands a huge variety of dynamic developments, driven by techno-logical, organizational as well as market changes. Within this dynamic environ-ment, logistics management demands a competent and flexible workforce, up-dated by current training and qualification tools. Publication of this research paper marks the midpoint of the project 'MARTINA', which does encompass the development of a smartphone-based edugaming-app as well as related efforts towards defining a topical map for ongoing qualification in logistics. While the latter has been the main focus of project work in the first two quarters of 2016, general game design as well as software prototype devel-opment have been taken on since. The prototype is as of 2017 being released in iterative steps, each delivering additional content/and or fixes to issues having been discovered during the user tests now running in parallel. This approach en-sures that the final edugaming-app will be relevant and useful for blue- and white-collar employees. Further benefit is the transferrability of game concepts to mul-tiple upcoming qualification topics. This research paper documents the process of iterative software development applied in the project, technical considerations with respect to conditions given by the android ecosystem as well as the realiza-tion of content-independent transferability. Section four contains extensive review and evaluation from an aesthetics and design studies perspective, while section five provides an outline of upcoming milestones in the project MARTINA (further topics and educational games)

Modelling chemistry in the nocturnal boundary layer above tropical rainforest and a generalised effective nocturnal ozone deposition velocity for sub-ppbv NOx conditions

Measurements of atmospheric composition have been made over a remote rainforest landscape. A box model has previously been demonstrated to model the observed daytime chemistry well. However the box model is unable to explain the nocturnal measurements of relatively high [NO] and [O3], but relatively low observed [NO2]. It is shown that a one-dimensional (1-D) column model with simple O3 -NOx chemistry and a simple representation of vertical transport is able to explain the observed nocturnal concentrations and predict the likely vertical profiles of these species in the nocturnal boundary layer (NBL). Concentrations of tracers carried over from the end of the night can affect the atmospheric chemistry of the following day. To ascertain the anomaly introduced by using the box model to represent the NBL, vertically-averaged NBL concentrations at the end of the night are compared between the 1-D model and the box model. It is found that, under low to medium [NOx] conditions (NOx <1 ppbv), a simple parametrisation can be used to modify the box model deposition velocity of ozone, in order to achieve good agreement between the box and 1-D models for these end-of-night concentrations of NOx and O3. This parametrisation would could also be used in global climate-chemistry models with limited vertical resolution near the surface. Box-model results for the following day differ significantly if this effective nocturnal deposition velocity for ozone is implemented; for instance, there is a 9% increase in the following day’s peak ozone concentration. However under medium to high [NOx] conditions (NOx > 1 ppbv), the effect on the chemistry due to the vertical distribution of the species means no box model can adequately represent chemistry in the NBL without modifying reaction rate constants

Addressing illicit trafficking through a crime convergence lens: towards a model for cross-border cooperation in Africa

Scholars and practitioners alike have found illicit cross-border flows - from drugs to wildlife and weapons - to converge and reinforce each other while often being embedded in large transnational criminal networks. However, practitioners still lack the tools and guidance to effectively combat these links in an integrated fashion. Cross-border cooperation initiatives across Africa are in a unique position to mitigate illicit trafficking, and yet, there is no conceptual model that could guide initiatives in doing so. This Knowledge Note seeks to bridge this gap in the context of BICC's small arms control work in Africa. It provides an initial selection of six building blocks (I-VI) that could structure and guide our future work on cross-border cooperation to reduce the illicit trafficking of small arms and light weapons (SALW) and ammunition in East Africa and beyond. The proposed model brings together a review of practice and policy advice on different illicit flows, thus showing how they are connected. It embraces the opportunity to put on a broader lens and look beyond the realm of arms trafficking. Across the six building blocks, the willingness of all actors to engage in long-term, sustainable and evidence-based cooperation as well as to ensure political buy-in at all levels seem crucial for cross-border efforts to be effective. Follow-up engagements and testing in the field are to refine this desk study's initial model

Divergent Realities

Divergent Realities is a dark room installation that provides divergent perspectives between a black and white computer-generated audiovisual experience and a synesthetic perspective of that same environment through a binocular headset with technology similar to augmented reality. It explores and contrasts our perceived reality through technology and is meant to inspire reflection about how our reality could be perceived through machines.https://remix.berklee.edu/graduate-studies-production-technology/1074/thumbnail.jp

Proteomic Analysis of Chloroplast-to-Chromoplast Transition in Tomato Reveals Metabolic Shifts Coupled with Disrupted Thylakoid Biogenesis Machinery and Elevated Energy-Production Components

A comparative proteomic approach was performed to identify differentially expressed proteins in plastids at three stages of tomato(Solanum lycopersicum) fruit ripening (mature-green, breaker, red). Stringent curation and processing of the data from three independent replicates identified 1,932 proteins among which 1,529 were quantified by spectral counting. The quantification procedures have been subsequently validated by immunoblot analysis of six proteins representative of distinct metabolic or regulatory pathways. Among the main features of the chloroplast-to-chromoplast transition revealed by the study, chromoplastogenesis appears to be associated with major metabolic shifts: (1) strong decrease in abundance of proteins of light reactions (photosynthesis, Calvin cycle, photorespiration)and carbohydrate metabolism (starch synthesis/degradation), mostly between breaker and red stages and (2) increase in terpenoid biosynthesis (including carotenoids) and stress-response proteins (ascorbate-glutathione cycle, abiotic stress, redox, heat shock). These metabolic shifts are preceded by the accumulation of plastid-encoded acetyl Coenzyme A carboxylase D proteins accounting for the generation of a storage matrix that will accumulate carotenoids. Of particular note is the high abundance of proteins involved in providing energy and in metabolites import. Structural differentiation of the chromoplast is characterized by a sharp and continuous decrease of thylakoid proteins whereas envelope and stroma proteins remain remarkably stable. This is coincident with the disruption of the machinery for thylakoids and photosystem biogenesis (vesicular trafficking, provision of material for thylakoid biosynthesis, photosystems assembly) and the loss of the plastid division machinery. Altogether, the data provide new insights on the chromoplast differentiation process while enriching our knowledge of the plant plastid proteome