The Mid-Infrared Instrument for the James Webb Space Telescope, VII: The MIRI Detectors

The MIRI Si:As IBC detector arrays extend the heritage technology from the Spitzer IRAC arrays to a 1024 x 1024 pixel format. We provide a short discussion of the principles of operation, design, and performance of the individual MIRI detectors, in support of a description of their operation in arrays provided in an accompanying paper (Ressler et al. (2015)). We then describe modeling of their response. We find that electron diffusion is an important component of their performance, although it was omitted in previous models. Our new model will let us optimize the bias voltage while avoiding avalanche gain. It also predicts the fraction of the IR-active layer that is depleted (and thus contributes to the quantum efficiency) as signal is accumulated on the array amplifier. Another set of models accurately predicts the nonlinearity of the detector-amplifier unit and has guided determination of the corrections for nonlinearity. Finally, we discuss how diffraction at the interpixel gaps and total internal reflection can produce the extended cross-like artifacts around images with these arrays at short wavelengths, ~ 5 microns. The modeling of the behavior of these devices is helping optimize how we operate them and also providing inputs to the development of the data pipeline

La grâce et la reconnaissance. De l'anthropologie du don de Marcel Hénaff à la théologie sacramentaire de Louis-Marie Chauvet

Explorer la grâce à la lumière des pratiques de don étudiées par Marcel Mauss a une pertinence tout à la fois anthropologique et théologique, donc humaine : telle est l’hypothèse qui est à l’origine de cette recherche de théologie systématique. Concrètement, il s’agit de vérifier cette hypothèse à partir d’une lecture analytique des travaux de deux auteurs qui, dans leurs champs disciplinaires respectifs, se sont intéressés à l’«Essai sur le don» de Mauss pour repenser la grâce, et qui ont aussi accordé une attention soutenue à la dimension rituelle des pratiques de don. Du côté de l’anthropologie, Marcel Hénaff rattache explicitement la grâce – pratiques et pensées diverses – à la tradition du «don réciproque cérémoniel» dans les sociétés segmentaires, mais il montre aussi et surtout en quoi elle implique une transformation majeure de cette tradition. Tant du côté du don cérémoniel que de celui de la grâce, il s’agit de reconnaissance publique et de lien social – dit autrement, de symbolisme –, mais il s’agit aussi de formes distinctes. Autant il importe de rattacher ces diverses formes aux contextes et aux types d’organisation sociale qui les portent, autant il importe également de prendre en considération la part «invisible» de la reconnaissance pour bien comprendre ce qui s’y joue, c’est-à-dire la reconnaissance avec les diverses figures de l’invisible – esprits, ancêtres, dieux. De plus, la pensée anthropologique de la reconnaissance de Marcel Hénaff jette un éclairage singulier sur la tradition chrétienne et sur ce qu’elle a fait du don. Du côté de la théologie chrétienne, Louis-Marie Chauvet pense lui aussi la grâce en lien avec les travaux de Mauss sur le don. Bien que sa théorie du «symbolique» soit hétéroclite, le don cérémoniel comme «échange symbolique» y occupe une place de choix. L’échange symbolique va même jusqu’à configurer le champ des questions, et il intervient de manière centrale dans sa théologie de l’alliance chrétienne et de la grâce. Il en va de même pour l’eucharistie, qu’il approche comme un rituel/sacrement de don à partir duquel il interroge l’héritage chrétien de la grâce. À plusieurs égards, les travaux d’Hénaff et de Chauvet s’appellent et se complètent. Le premier est attentif aux rituels dans les sociétés segmentaires et il manifeste une authentique curiosité théologique. Cependant, il en dit peu sur la ritualité chrétienne. Le second, quant à lui, est attentif aux rituels chrétiens et il manifeste une authentique curiosité anthropologique, mais il tend parfois à sous-estimer l’écart entre l’«échange symbolique» dans les sociétés segmentaires et ce qui pourrait être l’«échange symbolique» dans le christianisme. Enfin, tous les deux portent une interrogation de fond sur les sociétés occidentales modernes, sur leurs fécondités, mais aussi sur les défis qu’elles doivent affronter, notamment en ce qui concerne le lien social et les empiétements de l’économique sur l’ensemble des secteurs de vie. À partir des travaux de ces deux auteurs, la présente recherche vise donc à faire entendre certaines des résonnances actuelles de l’alliance chrétienne et de la grâce en ce qui concerne l’avènement du sujet croyant, le lien ecclésial, la vie sacramentaire et la participation des Églises à la société civile et au lien social en contexte de modernité occidentale.Exploring grace in light of the gift practices studied by Marcel Mauss is relevant from an anthropological standpoint as much as from a theological standpoint: such is the hypothesis explored in this systematic theology research. Precisely, this hypothesis is tested through an analytical reading of the works of two authors who, in their respective fields and with the ambition of rethinking grace, showed a resolute interest in Mauss’s essay on the gift and devoted a special attention to the ritual dimension of gift practices. In his work, Marcel Hénaff considers grace from an anthropological point of view and relates it – with its diverse practices and theories – to the ceremonial gift exchange tradition which can be found in societies without a central state, but he also mainly shows how it implies a major transformation of this tradition. Ceremonial gift exchange and grace are primarily concerned with public recognition and social bonding – in other words, with symbolism – but that recognition is also embodied in very different institutions. In order to understand what is at stake in these different forms of recognition, it is essential not only to relate them to the different types of social organization in which they are found, but also to consider their «invisible» part, that is the relationships with the diverse figures of the invisible – spirits, ancestors, gods. This is how Marcel Hénaff’s anthropology of recognition sheds light on the Christian tradition and on its handling of the gift. In Christian theology, Louis-Marie Chauvet also approaches grace in relation to Mauss’s essay and thinking on gift practices. In Chauvet’s variegated theory of the «symbolic», the ceremonial gift as a «symbolic exchange» stands out. The vocabulary associated with symbolic exchange not only formulates the important questions, it is also central in his theology of Christian covenant and grace. The same applies to the Eucharist, which he addresses as a gift ritual and through which he examines the Christian heritage of grace. In many ways, Hénaff’s and Chauvet’s work complete each other. The former is mindful of the rituals in societies without a central state and shows an authentic theological curiosity. However, he does not say much about Christian rituality. The latter is mindful of Christian rituals and shows an authentic anthropological curiosity, but he tends to underestimate the difference between «symbolic exchange» in societies without a central state and what could be a Christian «symbolic exchange». Finally, both examine and question western and modern societies regarding their possibilities, but also the challenges they are facing concerning social bonding, as well as the overlapping of economic exchanges in every sphere of life. The objective of this research and its analysis of the works of these two authors is to enlighten today’s relevance of covenant and grace in its various aspects: the advent of the subject, the ecclesiological bond, the sacramental life and the participation of Christian Churches in the social life in western modernity

Museum Governance: Lessons From the Past as a First Step Towards Innovation

Over the past thirty years, private sector governance has seen significant development in regulatory guidelines, best practices, and adaptation to emerging challenges. In contrast, the history of Canadian museum governance is relatively new. Not-for-profit Canadian museums began to establish governance frameworks only recently with influential publications like the UNESCO Recommendation on Museums and Collections (2015) and the SMQ Guide (2014), along with the implementation of Bill 114 in 2016. Bill 114 introduced constraints and responsibilities akin to those in the private sector, shifting governance from a more informal approach to a structured system. Notable examples of pre-Bill 114 governance include Rolland Arpin's initiatives at the Museum of Civilization and guidelines by the Canadian Art Museum Directors Organization. This study aims to explore the lessons that museum governance can learn from private sector practices, comparing regulatory frameworks and drawing insights from corporate governance literature to enhance the sustainability and effectiveness of not-for-profit museums and heritage preservation efforts

Automated grain size measurements from airborne remote sensing for long profile measurements of fluvial grain sizes

Recent research has demonstrated that image processing can be applied to derive surficial median grain size data automatically from high-resolution airborne digital imagery in fluvial environments. However, at the present time, automated grain size measurement is limited to the dry exposed bed areas of the channel. This paper shows that the application area of automated grain size mapping can be extended in order to include the shallow wetted areas of the channel. The paper then proceeds to illustrate how automated grain size measurement in both dry and shallow wetted areas can be used to measure grain sizes automatically for long river lengths. For the present study, this results in a median grain size profile covering an 80 km long river which is constructed from over three million automated grain size measurements

Synergistic Effects of Apigenin and Paclitaxel on Apoptosis of Cancer Cells

BACKGROUND: It was well known that the clinical use of chemotherapeutic drugs is restricted by severe adverse reactions and drug resistances. Thus it is necessary to figure out a strategy to increase the specific anti-tumor efficiency of chemotherapeutic drugs. Apigenin, a kind of flavonoids, has been reported to possess anticancer activities with very low cytotoxicity to normal tissue. METHODOLOGY/PRINCIPAL FINDINGS: Our results from cell viability assay, western-blots and TdT-mediated dUTP-biotin nick end labeling (TUNEL) assay demonstrated the synergistic pro-apoptotic effects of a low dose of apigenin and paclitaxel in human cancer cell lines. To analyze the underlying mechanism, we examined reactive oxygen species (ROS) staining after cells were treated with a combination of apigenin and paclitaxel, or each of them alone. Data from flow-cytometry showed that superoxides but not reduction of peroxides accumulated in HeLa cells treated with apigenin or a combination of apigenin and paclitaxel. Apigenin and paclitaxel-induced HeLa cell apoptosis was related to the level of ROS in cells. We further evaluated activity and protein level of superoxide dismutase (SOD). Apigenin significantly inhibited SOD activity but did not alter the SOD protein level suggesting that apigenin promoted ROS accumulation through suppressing enzyme activity of SOD. Addition of Zn(2+), Cu(2+) and Mn(2+) to cell lysates inhibited apigenin's effects on SOD activity. At the same time, data from caspase-2 over-expression and knocked-down experiments demonstrated that caspase-2 participated in apigenin and paclitaxel-induced HeLa cell apoptosis. CONCLUSIONS/SIGNIFICANCE: Taken together, our study demonstrated that apigenin can sensitize cancer cells to paclitaxel induced apoptosis through suppressing SOD activity, which then led to accumulation of ROS and cleavage of caspase-2, suggesting that the combined use of apigenin and paclitaxel was an effective way to decrease the dose of paclitaxel taken

sPlot - a new tool for global vegetation analyses

Aims: Vegetation-plot records provide information on the presence and cover or abundance of plants co-occurring in the same community. Vegetation-plot data are spread across research groups, environmental agencies and biodiversity research centers and, thus, are rarely accessible at continental or global scales. Here we present the sPlot database, which collates vegetation plots worldwide to allow for the exploration of global patterns in taxonomic, functional and phylogenetic diversity at the plant community level. Results: sPlot version 2.1 contains records from 1,121,244 vegetation plots, which comprise 23,586,216 records of plant species and their relative cover or abundance in plots collected worldwide between 1885 and 2015. We complemented the information for each plot by retrieving climate and soil conditions and the biogeographic context (e.g., biomes) from external sources, and by calculating community-weighted means and variances of traits using gap-filled data from the global plant trait database TRY. Moreover, we created a phylogenetic tree for 50,167 out of the 54,519 species identified in the plots. We present the first maps of global patterns of community richness and community-weighted means of key traits. Conclusions: The availability of vegetation plot data in sPlot offers new avenues for vegetation analysis at the global scale