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Insects and Colors between Art and Natural History
No full textThis book explores how European naturalists and artists perceived, investigated, and presented the relationship between insects and colors from the late sixteenth to the late eighteenth century. The contributors to this volume examine the creative methods and strategies that were developed to record color-related information about insects through studies on Hoefnagel’s glazed metal and hand-coloring practices; the lepidochromy technique used in paintings by Marseus van Schriek and later naturalists; the representation of sexual dimorphism of color and variable color of caterpillars in the images of Goedaert, Merian, Albin, and Rösel von Rosenhof; the painting-by-numbers technique applied to Schäffer’s bookplates on Regensburg insects; Schiffermüller’s watercolor originals of caterpillars; and finally, the color fading of exotic cabinet specimens and how this issue was tackled by Abbot and Smith. The volume is lavishly illustrated with rare and unpublished images and offers new insights into the interrelation between natural history and visual practices concerning the color of insects, with a special focus on butterflies and moths.publishe
Demethylation of methylguanidine by a stepwise dioxygenase and lyase reaction
No full textGuanidine-responsive riboswitches control genes that enable either detoxification or assimilation of guanidino compounds. In Vreelandella boliviensis and other halophilic bacteria, genes encoding the guanidine carboxylase pathway are found in a guanidine riboswitch-regulated operon, along with two uncharacterized genes annotated as 2-oxoglutarate (2-OG/Fe(II))-dependent dioxygenase family protein and hypothetical protein, respectively. Here we show that the 2-OG/Fe(II)-dependent dioxygenase efficiently hydroxylates methylguanidine. The resulting N-(hydroxymethyl)guanidine constitutes an unexpectedly stable hemiaminal that slowly decays to guanidine and formaldehyde. The second protein strongly accelerates the fragmentation of N-(hydroxymethyl)guanidine into guanidine and formaldehyde, thus acting as N-(hydroxymethyl)guanidine lyase. Interestingly, the class II guanidine riboswitch in front of the guanidine carboxylase gene does not discriminate between guanidine and methylguanidine, whereas the guanidine class I riboswitch at the start of the entire operon is specific for guanidine. V. boliviensis exhibits growth in minimal media with either guanidine or methylguanidine as sole nitrogen source. Comparative proteome analysis revealed that the entire guanidine carboxylase operon is strongly expressed under these conditions. The presented study broadens our understanding of guanidine metabolism by describing two enzymatic activities that jointly catalyze the demethylation of methylguanidine.publishe
Electronically Preresonant Coherent Anti-Stokes Raman Scattering Microscopy
No full textCoherent anti-Stokes Raman scattering (CARS) and stimulated Raman scattering (SRS) microscopy are key techniques for label-free vibrational imaging. However, their application is often limited by poor sensitivities. Recent advancements have shown that similar to spontaneous resonance Raman spectroscopy, SRS microscopy sensitivity can be greatly enhanced under electronic preresonance conditions. While electronic enhancement of CARS signals in spectroscopy was reported in the 1970s, its application in microscopy remains less explored. This study presents experimental results demonstrating significant sensitivity enhancements in CARS microscopy by choosing excitation wavelengths near electronic transitions in sample molecules, achieving detection levels down to low micromolar concentrations. We also conducted both experimental and theoretical investigations on spectra with and without electronic resonances, addressing the background signals encountered when using this method. Our findings advance the understanding of electronic preresonance effects in CARS and offer practical sensitivity enhancements, broadening the scope for coherent Raman imaging at lower concentrations.publishe
Bluebell : An Alliance of Relational Lifting and Independence for Probabilistic Reasoning
No full textWe present Bluebell, a program logic for reasoning about probabilistic programs where unary and relational styles of reasoning come together to create new reasoning tools. Unary-style reasoning is very expressive and is powered by foundational mechanisms to reason about probabilistic behavior like independence and conditioning. The relational style of reasoning, on the other hand, naturally shines when the properties of interest compare the behavior of similar programs (e.g. when proving differential privacy) managing to avoid having to characterize the output distributions of the individual programs. So far, the two styles of reasoning have largely remained separate in the many program logics designed for the deductive verification of probabilistic programs. In Bluebell, we unify these styles of reasoning through the introduction of a new modality called “joint conditioning” that can encode and illuminate the rich interaction between conditional independence and relational liftings; the two powerhouses from the two styles of reasoning.publishe
Balancing ecotourism and wildlife management through a conservation behavior approach
No full textEcotourism promises to reconcile wildlife conservation and human development if negative impacts of human visitation and associated infrastructure can be minimized. Animal behavior studies can be used to identify individual and population responses to anthropogenic impacts before other fitness consequences are documented. With input from professionals in animal behavior and ecotourism, we identified key questions needed to better understand the impact of ecotourism on wildlife. Activity budgets, foraging, movement, stress, habituation, and reproduction were themes that emerged from our survey. We highlight promising research on these themes and identify remaining behavioral research questions about conserving wildlife in the context of ecotourism. Although ecotourism activities often have detrimental effects on animal behavior, we highlight research needs that can inform management and ecotourist education to improve human behavior to be more compatible with sustainable use of nature.publishe
Mercurial Acting : Travelling Tragedy and Travelling Troupes in 17th- and 18th-Century Germany
No full textpublishe
The Unequal Flexibility Paradox : How Context Shapes Work-Life Boundaries and Inequality
No full textFlexible working arrangements in terms of time and location of work (flexitime and work from home) have become more common in recent decades, with the COVID-19 pandemic accelerating their adoption. While flexibility has the potential to help workers better reconcile work and private spheres, previous research has yielded ambivalent findings regarding its impact on well-being, work–life conflict, and the division of domestic and paid work among different population groups. This mismatch between the potential and actual outcomes of flexible work is known as the flexibility paradox. This dissertation extends earlier work on this paradox by exploring how the consequences of flexible work are shaped by contextual factors, particularly gender role attitudes, division of domestic work in a couple, and the flexibility stigma. It applies theories of work-family interface, gender, and social context using longitudinal and cross-national survey data.publishe
Evaluation von komplementären Benutzerschnittstellen als gestaltungsleitende Tätigkeit
No full textDie Dissertation untersucht komplementäre Benutzerschnittstellen (Complementary Interfaces), die als Vertreter für ubiquitäre Computing-Umgebungen dienen. Complementary Interfaces sind bedeutsame Kombinationen von Eingabe- und Ausgabeschnittstellen, die Nutzer:innen bei ihrer Arbeit unterstützen. In kontrollierten Laborexperimenten wird untersucht, wie diese Schnittstellen gestaltet und evaluiert werden können. Drei Anwendungsfälle dienen als Grundlage, um den Einfluss verschiedener Ausgabemodalitäten, Eingabetechniken und deren Wechselwirkungen zu untersuchen. Ein weiterer Fokus liegt auf der kognitiven Arbeitsbelastung und deren Messung als möglicher Untersuchungsgegenstand in Benutzerstudien. Die Arbeit zeigt, wie Geräte und Modalitäten kombiniert werden können und eröffnet Perspektiven für dynamische, kollaborative Systeme, die eine Symbiose interaktiver Systeme ermöglichen.publishe
Quantifying the amplitudes of ultrafast magnetization fluctuations in Sm<sub>0.7</sub> Er<sub>0.3</sub> Fe O<sub>3</sub> using femtosecond noise-correlation spectroscopy
No full textSpin fluctuations are an important issue for the design and operation of future spintronic devices. Femtosecond noise-correlation spectroscopy (FemNoC) was recently applied to detect ultrafast magnetization fluctuations. FemNoC gives direct access to the spontaneous fluctuations of magnetization in magnetically ordered materials. In FemNoC experiments, the magnetic fluctuations are imprinted on the polarization state of two independent femtosecond probe pulses upon transmission through a magnetic sample. Using a subharmonic demodulation scheme, the cross-correlation of the signals from both pulse trains is calculated. Here, we quantitatively link the FemNoC output signal to an optical polarization rotation, and then in turn to the magnitude of the inherent spin fluctuations. To this end, three different calibration protocols are presented and compared in accuracy. Ultimately, we quantitatively determine both the variance of optical polarization noise in rad2 and that of the ultrafast magnetization fluctuations in (A/m)2.publishe
Seasonal changes rather than competition drive inorganic and organic nitrogen acquisition and internal allocation in temperate trees
No full textFor trees, soil nitrogen (N) acquisition and its internal allocation to different tissues are driven by species’ properties (e.g. growth rate, nutrient demand), the interactions among tree species, and their abiotic environment. Over the growing season, abiotic changes in, e.g. temperature and rainfall affect biogeochemical N cycling as well as N allocation and remobilisation processes in trees. We studied the influence of seasonality and developmental variation in woody seedlings, focussing on tree-tree interactions. We investigated the interaction effects among seven temperate European tree species on their inorganic and organic net N uptake capacity, internal allocation of N to metabolically active and storage tissues, and morphological traits at four leaf developmental stages over the growing season (i.e. before bud break, after leaf development, before / after leaf senescence). Seedlings of seven temperate European tree species were grown in mesocosms under natural forest conditions in intra- or interspecific competition. At the beginning of the growing season, organic N was favoured over inorganic N, whereas in autumn all N sources were taken up equally. Within species, N uptake and internal allocation generally varied over the growing season, except for N acquisition in Carpinus. Among tree species, the differences in N uptake and allocation were more related to species-specific morphological and physiological root traits, rather than functional properties. The outcome of the interactions was not generally affected within a tree community over the growing season but depended on the individual species. Thus, seasonal variation and species-specific properties should be considered for mixed species forests.publishe