Quantifying the Influence of Surface Texture and Shape on Structure from Motion 3D Reconstructions

In general, optical methods for geometrical measurements are influenced by the surface properties of the examined object. In Structure from Motion (SfM), local variations in surface color or topography are necessary for detecting feature points for point-cloud triangulation. Thus, the level of contrast or texture is important for an accurate reconstruction. However, quantitative studies of the influence of surface texture on geometrical reconstruction are largely missing. This study tries to remedy that by investigating the influence of object texture levels on reconstruction accuracy using a set of reference artifacts. The artifacts are designed with well-defined surface geometries, and quantitative metrics are introduced to evaluate the lateral resolution, vertical geometric variation, and spatial–frequency information of the reconstructions. The influence of texture level is compared to variations in capturing range. For the SfM measurements, the ContextCapture software solution and a 50 Mpx DSLR camera are used. The findings are compared to results using calibrated optical microscopes. The results show that the proposed pipeline can be used for investigating the influence of texture on SfM reconstructions. The introduced metrics allow for a quantitative comparison of the reconstructions at varying texture levels and ranges. Both range and texture level are seen to affect the reconstructed geometries although in different ways. While an increase in range at a fixed focal length reduces the spatial resolution, an insufficient texture level causes an increased noise level and may introduce errors in the reconstruction. The artifacts are designed to be easily replicable, and by providing a step-by-step procedure of our testing and comparison methodology, we hope that other researchers will make use of the proposed testing pipeline

Som sagt så gjort? Betydningen af lederens personlige troværdighed for medarbejdermotivation, når der bedrives transformationsledelse

Ledere er troværdige, når deres medarbejdere vurderer, at de vil handle i overensstemmelse med deres udtrykte intentioner. Spørgsmålet er, om medarbejdernes oplevelse af lederens personlige troværdighed har betydning for deres motivation? Vi undersøger dette med et survey-eksperiment, hvor vi eksponerer 817 Mturk-respondenter for forskellige videovignetter, der manipulerer en fiktiv leders troværdighed, når lederen udøver transformationsledelse. Resultaterne viser signifikante forskelle på den oplevede ledertroværdighed. Disse forskelle i personlig ledertroværdighed viser sig at påvirke respondenternes selvangivne motivation samt den tid, de bruger på at løse opgaver for lederen. Artiklens vigtigste bidrag er påvisningen af, at det er muligt at påvirke oplevelsen af personlig ledertroværdighed eksperimentelt, og at det kan påvirke motivationen hos respondenterne. Artiklen viser, at det er relevant at udbygge forskningen i ledertroværdighed

Lipolysis drives expression of the constitutively active receptor GPR3 to induce adipose thermogenesis

Thermogenic adipocytes possess a therapeutically appealing, energy-expending capacity, which is canonically cold-induced by ligand-dependent activation of β-adrenergic G protein-coupled receptors (GPCRs). Here, we uncover an alternate paradigm of GPCR-mediated adipose thermogenesis through the constitutively active receptor, GPR3. We show that the N terminus of GPR3 confers intrinsic signaling activity, resulting in continuous Gs-coupling and cAMP production without an exogenous ligand. Thus, transcriptional induction of Gpr3 represents the regulatory parallel to ligand-binding of conventional GPCRs. Consequently, increasing Gpr3 expression in thermogenic adipocytes is alone sufficient to drive energy expenditure and counteract metabolic disease in mice. Gpr3 transcription is cold-stimulated by a lipolytic signal, and dietary fat potentiates GPR3-dependent thermogenesis to amplify the response to caloric excess. Moreover, we find GPR3 to be an essential, adrenergic-independent regulator of human brown adipocytes. Taken together, our findings reveal a noncanonical mechanism of GPCR control and thermogenic activation through the lipolysis-induced expression of constitutively active GPR3.ISSN:0092-8674ISSN:1097-417

Inferring depression and its semantic underpinnings from simple lexical choices

Spatial demonstratives are highly frequent linguistic universals, with at least two contrastive expressions (proximal ("this") vs. distal ("that")) indicating physical, emotional or functional proximity of the speaker to the referent. Re- cent evidence based on the Demonstrative Choice Task (DCT), in which participants couple words with a spatial demonstrative, indicates that demonstrative use, in absence of a communicative context, may also be indicative of experienced or emotional proximity to the self in an imagined mental space. As depression is characterized by increased and maladaptive focus on the self, the DCT may be a simple and reliable way to elicit behaviors that enable inference on the presence of severe depressive states, and allow descriptions of the semantic characteristics of altered self-representation in such states. Using a 300-item DCT, this paper presents two studies investigating the extent to which the DCT can be used to detect depression, and describe its semantic markers. In two independent samples, classification models were trained to classify individuals with high versus low depression symptom severity based on DCT responses. Results showed that lexical choices on the DCT reliably predict depression in both studies. Further, the DCT replicated semantic patterns of negative affect previously observed to be associated with depression. The paradigm may provide novel insights into the semantic characteristics underlying depressive states, and potentially individual differences hereof