230 research outputs found
La vulgarisation scientifique sur le web. Étude des pratiques de vulgarisation de vidéastes et de podcasteurs et podcasteuses francophones indépendants (2020-2023)
No full textThis doctoral research focuses on the science popularisation practices of independent French-speaking youtubers and podcasters. Popularisation is understood as practices deployed across different media (books, press, radio, social networks, etc.), the aim of which is to disseminate knowledge outside a formal framework, aimed at a variety of audiences generally considered to be non-specialists. Monica Baur spoke to 60 content creators and carried out a content analysis and online ethnography of scientific videos and podcasts. The topics covered relate to the sciences in the broadest sense: the natural, experimental and formal sciences (chemistry, biology, mathematics, etc.), the humanities and social sciences (history, linguistics, etc.) and general culture and social issues. This thesis is structured around a number of themes, to understand how science enthusiasts make their knowledge accessible by publishing content online. Firstly, the researcher looked at the popularisers' sense of legitimacy and expertise. The question of the source of the message seems all the more thorny as it concerns subjects that potentially have a strong impact on the public's representations. One chapter also looks at the backgrounds and profiles of these creators, highlighting the importance of self-taught individuals in developing their knowledge and passing it on. Monica Baur then highlights the phenomenon of the platformisation of popularisation, i.e. the fact that knowledge mediation activities are linked to the constraints and logic of platforms. Demonetisations, changing policies, understanding of algorithms: popularisers are faced with various challenges relating to the creation of content on the Internet. The researcher also devotes a section to the form of popularisation, from the choice of subject to the promotion of content on social networks, including the use of figures of speech and the methodology for researching and consulting sources. The final chapter looks at collaboration between traditional agentsin the field of scientific and cultural outreach (museums, scientific institutions, etc.) and web-based popularisers. This type of collaboration has been popularised in particular by the videos produced between the Louvre and various video-makers, including Benjamin Brillaud of the history YouTube channel Nota Bene. Monica Baur sent out a questionnaire to a range of cultural and institutional agents (educational managers, teacher-researchers, outreach officers, etc.). These partnerships cover a wide range of activities, such as creating videos or podcast episodes on request, proofreading texts, commissioning illustrations, and providing logistical or documentary support, whether or not these projects are paid for. Popularisers can play an interesting role in building projects with other players in the science dissemination field.Cette recherche doctorale porte sur les pratiques de vulgarisation scientifique de vidéastes sur YouTube et de podcasteur·euses francophones indépendants. La vulgarisation est entendue comme des pratiques se déployant sur différents supports (livres, presse, radio, réseaux sociaux, etc.), dont l’objectif est de diffuser des connaissances en dehors d’un cadre formel, à destination de publics variés généralement considérés comme non spécialistes. Monica Baur s’est entretenue avec 60 créateur·trices de contenu et a mené une analyse de contenu ainsi qu’une ethnographie en ligne de vidéos et de podcasts scientifiques. Les thèmes traités sont relatifs aux sciences au sens large : les sciences naturelles, expérimentales et formelles (chimie, biologie, mathématiques, etc.), les sciences humaines et sociales (histoire, linguistique, etc.) et les sujets de culture générale et de société. Plusieurs axes structurent cette thèse, dont l’objectif est de comprendre et de mieux connaître comment des amateurs de sciences (au sens premier du terme, à savoir qui aiment les sciences) rendent leurs connaissances accessibles en publiant des contenus en ligne. D’abord, la chercheuse s’est intéressée au sentiment de légitimité et d’expertise des vulgarisateur·trices. La question de la source du message semble d’autant plus épineuse qu’elle touche des sujets qui ont potentiellement un fort impact sur les représentations du public. Un chapitre traite également du parcours et du profil de ces créateur·trices, mettant notamment en avant l’importance du parcours autodidacte dans le développement de leurs connaissances et dans la transmission de celles-ci. Monica Baur met ensuite en lumière le phénomène de plateformisation de la vulgarisation, c’est-à-dire le fait que les activités de médiation des savoirs sont liées avec les contraintes et logiques des plateformes. Démonétisations, politiques changeantes, suppression de fonctionnalités, compréhension des algorithmes : les vulgarisateur·trices sont amenés à faire face à différents défis relevant de la création de contenu sur Internet. La chercheuse consacre aussi une partie à la mise en forme et à la mise en scène de la vulgarisation, du choix du sujet jusqu’à la promotion des contenus sur les réseaux sociaux, en passant par l’usage des figures de styles et la méthodologie de recherche et de consultation des sources. Enfin, un dernier chapitre concerne les collaborations entre acteurs traditionnels de la médiation scientifique et culturelle (musées, institutions scientifiques, etc.) et vulgarisateur·trices du web. Ce type de collaborations a été popularisé notamment par les vidéos réalisées entre le Louvre et différents vidéastes dont Benjamin Brillaud de la chaîne d’histoire Nota Bene. Monica Baur a adressé un questionnaire à différents profils d’acteurs culturels et institutionnels (responsables pédagogiques, enseignants-chercheurs, chargés de médiation, etc.). Ces partenariats renvoient à une gamme très variée d’activités comme la création de vidéos ou d’épisodes de podcasts sur demande, la relecture de textes, la commande d’illustrations, le soutien logistique ou documentaire, que ces projets soient rémunérés ou non. Les vulgarisateur·trices peuvent jouer un rôle intéressant pour construire des projets avec d’autres acteurs de la diffusion scientifique.(COMU - Information et communication) -- UCL, 202
Testudo guntheri Baur 1889
No full textTestudo guntheri Baur, 1889 Current name: unclear Syntype (1 specimen): OUM 8656 (articulated skeleton, SCL 79 cm). Remarks: “ Testudo güntheri ” was erected by Baur (1889: p. 1044) for the tortoises that were placed in the species Testudo elephantopus by Günther (1877). The latter author states that he referred five specimens to Testudo elephantopus (pp. 63–64); one from the Oxford Museum (now catalogued as OUM 8656), two further specimens from the collection of the Free Public Museum, Liverpool, and one each from the collections of the British Museum (now Natural History Museum, London) and the Royal College of Surgeons, London. OUM 8656 is depicted on several plates in Günther (1877) and has been catalogued as “ Holotype of Testudo guntheri Baur ” in Oxford. However, it is clear from the list of specimens provided by Günther (1877) that OUM 8656 and the other four tortoises are syntypes. All of these tortoises have no exact locality data. Therefore, Testudo guntheri should best be treated as nomen dubium, although it has been previously identified with giant tortoises from the southwest of Albemarle Island, Galapagos (e.g., Wermuth & Mertens 1977; Fritz & Havaš 2007).Published as part of Nowak-Kemp, Małgosia & Fritz, Uwe, 2010, Chelonian type specimens at the Oxford University Museum, pp. 1-19 in Zootaxa 2604 (1) on page 16, DOI: 10.11646/zootaxa.2604.1.1, http://zenodo.org/record/530226
Disputatio Philosophica, exhibens Solis Quietem Et Terrae Motum
No full textQuam ... Praeside ... Dn. Georgio Othone ... Ad diem 23. August. Anno M.DC.XC. ... publice ventilaudam proponit Johan. Wernerus Baur/ Author & RespondensDruck mit allgemein formulierter Widmung "Deo Patriae & Amicis" auf der Rückseite des Titelbl
Human impact on the vegetation of limestone cliffs in the northern Swiss Jura mountains
Get PDFCliffs provide unique habitats for many specialised organisms, including
chamaephytes and slowly growing trees. Drought, high temperature
amplitude, scarcity of nutrients and high insolation are general characteristics
of exposed limestone cliff faces. The vegetation of limestone cliffs in the
Swiss Jura mountains consists of plants of arctic-alpine, continental and
Mediterranean origin. Several populations exhibit relicts from post- or
interglacial warm or cold climatic periods. Grazing goats and timber
harvesting influenced the forests surrounding the limestone cliffs in northern
Switzerland for many centuries. During the twentieth century, however, these
traditional forms of forest use were abandoned.
In recent years, rock climbing enjoys increasing popularity in mountain
areas at low elevation, where this sport can be performed during the whole
year. The limestone cliffs of the Jura mountains provide unique opportunities
for sport climbers. As a consequence, more than 2000 climbing routes with
fixed protection bolts have been installed on 48 rock cliffs in the region of
Basel, Switzerland.
Overgrowing forest, due to the abandonment of forestry and damages
due to recreational activities including rock climbing reduce the quality and
size of the cliff habitats. In my dissertation, I examined quantitative, spatial
and temporal patterns of human impacts on the cliff flora and on the genetic
population structure of two plant species on isolated cliffs in the Jura
mountains of northern Switzerland.
The assessment of plant cover and species density at various distances
from frequently used climbing routes in the region showed that plant cover
was significantly reduced at the base of climbing routes. Furthermore, species
density (number of species per m2) at the cliff base as well as plant cover and
species density on the cliff face tended to increase with distance from the
route.
The comparison of the vegetation at the cliff base and on the cliff face of
five frequently climbed cliffs with that of seven unclimbed cliffs indicated that
rock climbing significantly altered the plant composition. Specialised rock
species occurred less frequently on climbed cliffs than on unclimbed cliffs.
At the Gerstelflue, a popular recreational climbing site with rock climbing
activities since more than 40 years, plant cover and species density (number
of species per m2) were reduced in climbed areas. Rock climbing also
reduced the density (number of individuals per m2) of forbs and shrubs,
whereas the density of ferns tended to increase in climbed areas. In addition,
rock climbing caused a significant shift in plant species composition and
altered the proportions of different plant life forms.
Species diversity and cover of lichens, and possible associations
between lichens and lichen-feeding land snails were assessed in climbed and
unclimbed areas of 10 isolated cliffs. Total lichen species density was not
correlated with the complexity of the rock surface, climbing frequency and age
of the climbing route. The species density of epilithic lichens was lower along
climbing routes than in unclimbed areas, whereas no difference in species
density of endolithic lichens was found between climbed and unclimbed
areas. Furthermore, climbed and unclimbed areas did not differ in total lichen
cover. The dissimilarity of the lichen communities between climbed and
unclimbed areas increased with increasing climbing intensity on the focal
route in climbed areas, but not with the age of the climbing route. Within cliffs,
plots along climbing routes harboured fewer snail species and individuals than
plots in unclimbed areas.
The effects of forestry practices on the species richness and abundance
of vascular plants on the face, at the base and on the talus have been
investigated by comparing two different forestry practices (clear-cutting and
shelter tree cutting) with forest reserve (i.e. no management in the past 80
years)) on three cliffs. Plant species density and vegetation cover was higher
in the shelter-cut areas than in the forest reserves on the talus as well as at
the cliff base. Clear-cut areas showed a higher vegetation cover than forest
reserves on the talus. Shelter-cut areas harboured a larger proportion of
plants with high light demands and plant indicator species showed a higher
mean light score than in clear-cut areas and forest reserves.
The analysis of time-series of air photographs taken between 1951 and
2000 at six cliffs revealed an increase in tree cover from 60% to 85% between
1951 and 1964 after which the increase levelled off. The increase in tree
cover showed a distinct spatial pattern. It was significant in the talus and on
the cliff face, but not on the plateau (at the top of the cliffs).
Possible effects of isolation and the presumed colonisation history of
cliffs as well as of anthropogenic activities on the genetic population structure
of two plant species with different life-histories were assessed using RAPDpolymorphisms.
Fourteen populations of Draba aizoides L. and 12 populations
of Melica ciliata L. living on isolated limestone cliffs were examined. Analysis
of molecular variance revealed a high among-population variation of each
27% in the gene pools of both species. A clear isolation-by-distance pattern
and a separation of populations from the Jura mountains and the Alps were
found in D. aizoides. This provides evidence for glacial relict endemism in this
species, resulting from nunatak survival in the Jura mountains. In M. ciliata,
UPGMA-analysis showed clusters of plant populations growing on cliffs with
castles with shared historical incidents, indicating zoochorical dispersal
related to human settlements.
The various studies emphasise the uniqueness and vulnerability of the
limestone cliff ecosystem of northern Switzerland. Protection measures in
several fields of activity are needed to preserve the unique relict vascular
plant, lichen and animal communities. Adequate management actions should
be developed and implemented. Actions should particularly be directed to
cliffs with numerous arctic-alpine plant species to protect them from mechanic
disturbances by sport climbing and hiking. The prohibition of sport climbing on
cliffs with a high number of specialised plant or animal species and the
establishment of climbing-free protection zones in popular areas are the most
effective and adequate measures in this context. However, any management
plan should include a comprehensive information campaign to show the
potential impact of intensive sport climbing on the specialised flora and fauna
and to increase the compliance of these measures by the climbers. Forestry
practices that keep the supply of light on a high level at the lower parts of the
cliffs are required to preserve the relict plant species. Selective thinning on the
talus results in relatively large plots with good light conditions and therefore
promotes the rare, relict plant species with high light demands. Self
evidentely, forestry actions and climbing prohibitions should be executed in
coordination. Another measure to manage the lower parts of cliffs could be to
use them as temporal pastures for goats. Finally, the preservation of
mediaeval sites also connotes the conservation of plant species introduced
into the area during the time of human activities
Comparison of batch and continuous multi-column protein A capture processes by optimal design
Get PDFMulti-column capture processes show several advantages compared to batch capture. It is however not evident how many columns one should use exactly. To investigate this issue, twin-column CaptureSMB, 3- and 4-column periodic counter-current chromatography (PCC) and single column batch capture are numerically optimized and compared in terms of process performance for capturing a monoclonal antibody using protein A chromatography. Optimization is carried out with respect to productivity and capacity utilization (amount of product loaded per cycle compared to the maximum amount possible), while keeping yield and purity constant. For a wide range of process parameters, all three multi-column processes show similar maximum capacity utilization and performed significantly better than batch. When maximizing productivity, the CaptureSMB process shows optimal performance, except at high feed titers, where batch chromatography can reach higher productivity values than the multi-column processes due to the complete decoupling of the loading and elution steps, albeit at a large cost in terms of capacity utilization. In terms of trade-off, i.e. how much the capacity utilization decreases with increasing productivity, CaptureSMB is optimal for low and high feed titers, whereas the 3-column process is optimal in an intermediate region. Using these findings, the most suitable process can be chosen for different production scenarios
Elliptic boundary value problems and construction of Lp-strong feller processes with singular drift and reflection
No full textBenedict Baur presents modern functional analytic methods for construction and analysis of Feller processes in general and diffusion processes in particular. Topics covered are: Construction of Lp-strong Feller processes using Dirichlet form methods, regularity for solutions of elliptic boundary value problems, construction of elliptic diffusions with singular drift and reflection, Skorokhod decomposition and applications to Mathematical Physics like finite particle systems with singular interaction. Emphasize is placed on the handling of singular drift coefficients, as well as on the discussion of pointwise and pathwise properties of the constructed processes rather than just the quasi-everywhere properties commonly known from the general Dirichlet form theory. Contents Construction of Lp-Strong Feller Processes Elliptic Boundary Value Problems Skorokhod Decomposition for Reflected Diffusions with Singular Drift Particle Systems with singular interaction Target Groups Graduate and PhD students, researchers of Mathematics in the field (Functional) Analysis, Stochastics, Partial Differential Equations and Mathematical Physics The Author Benedict Baur has done his doctor’s degree at the University of Kaiserslautern in topics on Stochastics and Functional Analysis.
The invasive plant Impatiens glandulifera affects mycorrhizal fungi, plant and invertebrate diversity in deciduous forests
Get PDFNon-native plant species have the potential to affect an ecosystem by changing species diversity, community structure and interactions among organisms. It is therefore important to understand potential mechanisms that contribute to the success of invasive plants. In the context of my PhD thesis, I examined the effect of the invasive annual herb I. glandulifera on mycorrhizal, plant and invertebrate diversity in a deciduous forest near Basel (Switzerland). I also studied the potential mechanism that could contribute to the success of I. glandulifera. A controlled field experiment was set up in three forest areas that were affected to a different extend (little, moderatly, high) by a former wind storm. In each area, three different plot types were installed: plots invaded by I. glandulifera, plots from which the invasive plants had been manually removed and plots which were no yet colonized by the invasive plant. The results of my thesis demonstrate that I. glandulifera affects above and as well as belowground organisms and has the potential to change soil conditions.
Aboveground gastropod richness and abundance were found to be higher in invaded plots than in control plots. The presence of I. glandulifera also altered the composition of gastropod species. Belowground fewer types of ectomycorrhiza were found on root systems of F. sylvatica saplings. Moreover, in plots with I. glandulifera the composition of ectomycorrhiza morphotypes was shifted. Considering mycorrhizal colonisation on fine roots saplings of both tree species, the presence of the invasive plant resulted in a reduction of ectomycorrhizal colonisation of F. sylvatica saplings and of arbuscular mycorrhiza colonisation on A. pseudoplatanus. Thus, disruption of mycorrhizal symbiosis probably led to a lower biomass and survival rate in saplings of both species grown in invaded plots. Additional results showed that soil moisture, soil pH, available phosphorus and microbial activity were increased in invaded plots.
Increased gastropods abundance and richness could be explained by higher soil moistures and damped soil temperature in invaded plots. However, measured changes in soil conditions did not affect mycorrhizal colonisation and performance of both sapling species. Therefore allelopatic effects of I. glandulifera on mycorrhizal symbioses were also examined. Allelopatic compounds are known to contribute to the spread of some invasive plant species and can disrupt mycorrhizal symbiosis. I identified the allelopathic compound 2-methoxy-1,4-naphtoquinone (2-MNQ) in plant organs of I. glandulifera, in soil of its proximity and in rain water rinsed from its leaves. Specific bioassays using shoot and root extracts of I. glandulifera as well as synthetic 2-MNQ revealed strong inhibitory effects on mycelium growth of ectomycorrhiza fungi and on the germination of native forest herbs. This finding indicates that the release of 2-MNQ may contribute to the invasion success of I. glandulifera.
Health, function and diversity of forest ecosystems are closely linked to the abundance and richness of mycorrhizal fungi. This study demonstrates that the spread I. glandulifera into deciduous forest ecosystem resulted in lower mycorrhizal colonisation of saplings. Thus, forest regeneration might be strongly affected by I. glandulifera. Moreover, changes in soil chemistry and soil conditions induced by I. glandulifera caused shifts in above- and belowground communities. Therefore ecosystem services and functions of forest habitats can be affected. Removal or stopping the preceding spread of I. glandulifera may be an investment for the conservation of native species and may prevent potential losses in timber production
Richardson Elements for Parabolic Subgroups of Classical Groups in Positive Characteristic
No full textLet G be a simple algebraic group of classical type over an algebraically closed field k. Let P be a parabolic subgroup of G and let p = Lie P be the Lie algebra of P with Levi decomposition p = l circle plus u, where u is the Lie algebra of the unipotent radical of P and l is a Levi complement. Thanks to a fundamental theorem of Richardson (Bull. London Math. Soc. 6: 21-24, 1974), P acts on u with an open dense orbit; this orbit is called the Richardson orbit and its elements are called Richardson elements. Recently Baur (J. Algebra 297(1): 168-185, 2006), the first author gave constructions of Richardson elements in the case k = C for many parabolic subgroups P of G. In this note, we observe that these constructions remain valid for any algebraically closed field k of characteristic not equal to 2 and we give constructions of Richardson elements for the remaining parabolic subgroups
La lutte contre la désinformation sur YouTube : Étude d’une pratique de vulgarisation scientifique à travers le traitement du film La révélation des pyramides par des vidéastes vulgarisateurs
No full textL’auteure s’intéresse aux pratiques de vulgarisation scientifique de plateformes numériques, plus précisément YouTube, et celles de podcasts produits et diffusés exclusivement sur le web. Son questionnement porte sur l’usage des outils numériques dans les activités de médiation des savoirs, et plus précisément les pratiques de vulgarisation par des amateurs de science au sens large. L’auteure explorer les stratégies discursives déployées par des vidéastes vulgarisateurs, en regard d’un type de pratique de vulgarisation en particulier, le débunkage. Elle présente une analyse sémiopragmatique de cinq vidéos en réponse à un « documentaire » mis en ligne sur YouTube, La Révélation des pyramides, et identifié comme conspirationniste
Habrolepis italicus Delucchi
No full text<i>Habrolepis italicus</i> Delucchi (Encyrtidae) <p> <i>Habrolepis italicus</i> Delucchi, 1965: 302, 303. <b>Lectotype</b> m, Italy: Toscana, Pisa, hereby validated, selected by Noyes (VD [examined]).</p> <p> <i>Material</i>. LECTOTYPE m (cp) labelled`ex Asterolecanium?ilicicola! V. Delucchi leg.; PISA, 20.V.52 leg. F. Venturi; HABROLEPIS italicus n. sp. V. Delucchi det.; COTYPUS [red]’.</p> <p>PARALECTOTYPES, VD: 1 m (cp), ®ve slides (scx) with antennae and wings of several specimens. MHNG: 7 mm (cp). All specimens from the same locality as lectotype.</p> <p> <i>Remarks</i>. Delucchi also mentioned a female from Algiers, Algeria, which could not be traced.</p> <p> According to Podsiadlo (1993) the diagnostic characters on antenna and fore wing of <i>italicus</i> fall within the range of variation in <i>Habrolepis dalmani</i> (Westwood). The author suggested reconsidering the status of <i>italicus</i>.</p> <p> <i>Status.</i> <i>Habrolepis italicus</i> Delucchi.</p>Published as part of <i>Baur, Hannes, 2001, The Hymenoptera (Chalcidoidea, Ichneumonoidea, Platygastroidea) described by Vittorio Delucchi: an annotated catalogue, pp. 55-125 in Journal of Natural History 35 (1)</i> on page 82, DOI: 10.1080/002229301447899, <a href="http://zenodo.org/record/5275865">http://zenodo.org/record/5275865</a>
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