3D modeling of indoor environments by a mobile platform with a laser scanner and panoramic camera

One major challenge of 3DTV is content acquisition. Here, we present a method to acquire a realistic, visually convincing D model of indoor environments based on a mobile platform that is equipped with a laser range scanner and a panoramic camera. The data of the 2D laser scans are used to solve the simultaneous lo- calization and mapping problem and to extract walls. Textures for walls and floor are built from the images of a calibrated panoramic camera. Multiresolution blending is used to hide seams in the gen- erated textures. The scene is further enriched by 3D-geometry cal- culated from a graph cut stereo technique. We present experimental results from a moderately large real environment.

The interplay of short‐term mesophyll and stomatal conductance responses under variable environmental conditions

Understanding the short‐term responses of mesophyll conductance (gm) and stomatal conductance (gsc) to environmental changes remains a challenging yet central aspect of plant physiology. This review synthesises our current knowledge of these short‐term responses, which underpin CO2 diffusion within leaves. Recent methodological advances in measuring gm using online isotopic discrimination and chlorophyll fluorescence have improved our confidence in detecting short‐term gm responses, but results need to be carefully evaluated. Environmental factors like vapour pressure deficit and CO2 concentration indirectly impact gm through gsc changes, highlighting some of the complex interactions between the two parameters. Evidence suggests that short‐term responses of gm are not, or at least not fully, mechanistically linked to changes in gsc, cautioning against using gsc as a reliable proxy for gm. The overarching challenge lies in unravelling the mechanistic basis of short‐term gm responses, which will contribute to the development of accurate models bridging laboratory insights with broader ecological implications. Addressing these gaps in understanding is crucial for refining predictions of gm behaviour under changing environmental conditions

Business and human rights in the data economy: A mapping and research study

Digitalization is gaining importance rapidly. However, neither companies nor states have yet developed a sufficient understanding of the data economy’s human rights impacts. The study suggests that addressing the corporate responsibility of technology companies through a business and human rights lens has the benefit of anchoring the debate in internationally established norms and universally accepted human rights. Furthermore, discussing human rights in the data economy from this angle opens the possibility for companies to use or learn from managerial toolkits that have already been developed in this field

Enregistered spellings in interaction. Social indexicality in digital written communication

Against the backdrop of the societal differentiation of literacy, the paper investigates spelling variation in digital written communication beyond the binary paradigm of standard and nonstandard. To this end, the paper proposes a formal classification of digital spelling variants and then focuses on the socio-communicative functions of these variants in usage. Theoretically grounded in the notions of register and social indexicality, the paper discusses how spelling variants are metapragmatically ordered by social actors and deployed in text-messaging interactions in order to indicate interpretive context. To investigate these phenomena holistically, the paper furthermore presents a tripartite research framework that addresses digital writing regarding its I) structural variants, II) communicative practice, and III) reflexive awareness. Afterwards, this methodological approach is applied empirically. This is done based on a data set that includes samples of everyday literacy by 23 German adolescents: informal WhatsApp texting, on the one hand, formal school essays on the other. The exemplary analyses focus on phonostylistic spellings (e. g. elisions such as instead of ) and graphostylistic spellings (e. g. graphemic substitutions such as instead of ) in these WhatsApp interactions, reconstructing the metapragmatic status of standard orthography in digital writing. By combining structure-oriented, interactional, and ethnographic perspectives, the paper seeks a disciplinary dialogue by relating concepts of sociolinguistics and linguistic anthropology not only to research fields of media linguistics but also to research on writing systems

Photorespiration in the context of Rubisco biochemistry, CO2 diffusion and metabolism

Photorespiratory metabolism is essential for plants to maintain functional photosynthesis in an oxygen-containing environment. Because the oxygenation reaction of Rubisco is followed by the loss of previously fixed carbon, photorespiration is often considered a wasteful process and considerable efforts are aimed at minimizing the negative impact of photorespiration on the plant's carbon uptake. However, the photorespiratory pathway has also many positive aspects, as it is well integrated within other metabolic processes, such as nitrogen assimilation and C1 metabolism, and it is important for maintaining the redox balance of the plant. The overall effect of photorespiratory carbon loss on the net CO2 fixation of the plant is also strongly influenced by the physiology of the leaf related to CO2 diffusion. This review outlines the distinction between Rubisco oxygenation and photorespiratory CO2 release as a basis to evaluate the costs and benefits of photorespiration

Tryptophan synthase complexes: evolution, substrate specificity, and quaternary structure

The permanent tryptophan synthase complex (TS) serves as a model system for the investigation of sophisticated protein-protein interactions. The permanent TS consists of a dimer of β-subunits and two α-subunits, which are located at both sites of the dimer, resulting in a αββα arrangement. The α-subunit catalyzes the aldolytic cleavage of indole-3-glycerol-phosphate (IGP). Glyceraldehyde-3-phosphate (G3P) is released whereas indole is channeled through a hydrophobic tunnel to the active site of the β-subunit. There, it reacts with L-serine in a PLP-dependent condensation reaction to L-tryptophan and water. The quaternary assembly of the permanent TS enables the bi-directional activation of the subunits within the complex. This ensures the coordination of IGP cleavage and condensation of indole and L-serine to tryptophan. The effects of complex formation and allosteric communication on the enzymatic parameters of the subunits differ in detail in diverse extant organisms. We were interested in the questions how these differences reflect the evolutionary history and which characteristics a primordial TS might have featured. In order to answer these questions, a phylogenetic tree was constructed using concatenated αβ-sequences. The α- and β-sequences corresponding to the root of this tree are the most probable predecessor of permanent TS in the last common ancestor (LCA). The LCA α- and β-subunits were separately expressed in E. coli. Steady-state kinetics revealed that the LCA α-subunit is comparably active as extant α-subunits whereas the LCA β-subunit has a higher activity compared to extant β-subunits. A strong interaction between the LCA subunits with a Kd in the nanomolar range was detected by fluorescence titration. The formation of a LCA TS with αββα stoichiometry was verified by analytical size exclusion chromatography. Complex formation results in a significant increase of the activity of the α-subunit and a slight decrease of the activity of the β-subunit. The slow rate of tryptophan-release might be the rate-limiting step of the β-subunit in the LCA TS as indicated by stopped-flow experiments. Different accessibilities of isolated and complexed β-subunits indicated that a hydrophobic tunnel between the active sites had already existed in the LCA TS. Mutual adaptation of the subunits, which results in a more efficient catalysis of tryptophan and the specialization as tryptophan synthase, seems to have evolved recently to scope with the elevated need of fast-growing organisms for tryptophan. The TrpB enzyme family consists of the large group of TrpB1 enzymes (β-subunits of permanent TS) and the smaller group of TrpB2 enzymes. The sequence identity between the groups is less than 30 %, which indicates an early divergent evolution in the TrpB enzyme family. The active site of both groups differs in one position, which is an aspartate in all TrpB1 enzymes and an arginine in all TrpB2 enzymes. Whereas TrpB1 has a specificity for L-serine, TrpB2 uses O-phospho-L-serine (OPS) for the synthesis of tryptophan. The importance of the conserved arginine for the preference of OPS as substrate was validated by structural analysis of a TrpB2 enzyme with bound OPS and mutagenesis studies. The TrpB2 group is further subdivided into TrpB2i enzymes, which are encoded within the trp operon, and TrpB2a and TrpB2o enzymes, which are encoded outside of the trp operon. It had been previously shown that a transient, ligand-dependent TS with αββ stoichiometry is formed by ssTrpB2i and ssTrpA2 in S. solfataricus. The influence of ssTrpB2i ligands on the stability of the transient TS was investigated. It turned out that the β-substituent of a bound amino acid at the active site of ssTrpB2i does not influence the interaction with ssTrpA2. This indicates that chemical transformations at the β-subunit have no influence on the TS stability. Like in permanent TS, the active sites of the α- and β-subunits seem to be connected by a hydrophobic tunnel. Indications for the existence of the hydrophobic tunnel are: 1) the GP-bound α-subunit prevents the conversion of external indole to tryptophan, 2) only little indole is released during the TS reaction and 3) the main amount of indole formed at the α-subunit is immediately converted to tryptophan by the associated β-subunit. These notions argue for the early divergence in the TS evolution. The phylogeny of transient TS was investigated by a sequence similarity network (SSN) of the TrpA enzyme family. It revealed that TrpA2 enzymes also exist in organisms like Thermoplasma volcanium, which have only TrpB2a, encoded outside of the trp operon. This indicates that tvTrpA2 and tvTrpB2a form a transient, ligand-dependent TS. This hypothesis was validated by analytical size exclusion chromatography and SPR. A comparison of the structures of the permanent TS from S. typhimurium and the transient TS from S. solfataricus shows that they differ in the quaternary assembly of the subunits. While in the permanent TS three parts of stTrpB1 contribute to the interaction with stTrpA1, only one N-terminal part of ssTrpB2i interacts with ssTrpA2 in the transient TS. The transfer of this N-terminal part of ssTrpB2i or tvTrpB2a is sufficient to convert the non-interacting ssTrpB2a into an enzyme, capable of interacting with and activating an α-subunit (ssTrpA2 or tvTrpA2). This finding illustrates conservation in structure and conformational flexibility present within the family of TrpB2 enzymes

Introduction: The sociolinguistics of exclusion – Indexing (non)belonging in mobile communities

The special issue on ‘The sociolinguistics of exclusion: Indexing (non)belonging in mobile communities’ delves into the phenomenon of exclusion as a means and outcome of social positioning within diverse communities undergoing continual transformation due to social, demographic, political, and technological changes. Through empirical studies that critically engage with exclusionary discourse practices, this issue analyzes the semiotic means that social actors employ to presuppose and/or entail exclusion. Additionally, it explores the underlying ideological assumptions on which these choices are perceived, rationalized, justified, and/or contested as exclusionary

Associations between stress and migraine and tension-type headache: Results from a school-based study in adolescents from grammar schools in Germany

Introduction: Stress is considered the major contributor to migraine and tension-type headache in adolescents. Previous studies have focused on general stressors, whereas the aim of the present study was to investigate associations between individuals’ stressful experiences and different types of headache. Methods: Adolescents from 10th and 11th grades of grammar schools filled in questionnaires. Stressful experiences were measured with the Trier Inventory of Chronic Stress. Type of headache was classified according to the International Classification of Headache Disorders. Linear regressions, adjusted for sex and grade, were calculated to estimate differences in stress scores that can be attributed to migraine, tension-type headache or miscellaneous headache. Results: A total of 1260 questionnaires were analysed. Tension-type headache, migraine and co-existing migraine plus tension-type headache were found in 48.7%, 10.2% and 19.8% of the participants. In subjects with migraine or co-existing migraine plus tension-type headache, high increases in stress scores were found in all investigated dimensions, whereas much weaker and inconsistent associations were found in subjects with tension-type headache only. Conclusions: The characteristic of migraine is more associated with stressful experiences than this is the case for tensiontype headache. This suggests that adolescent migraine patients might specially benefit from behavioural interventions regarding stress