A sketching interface for 3D modeling of polyhedron

We present an intuitive and interactive freehand sketching interface for 3D polyhedrons reconstruction. The interface mimics sketching with pencil on paper and takes freehand sketches as input directly. The sketching environment is natural by allowing sketching with discontinuous, overlapping and multiple strokes. The input sketch is a natural line drawing with hidden lines removed that depicts a 3D object in an isometric view. The line drawing is interpreted by a series of 2D tidy-up processes to produce a vertex-edge graph for 3D reconstruction. A novel reconstruction approach based on three-line-junction analysis and planarity constraint is then used to approximate the 3D geometry and topology of the graph. The reconstructed object can be transformed so that it can be viewed from different viewpoints for interactive design or as immediate feedback to the designers. A new sketch can then be added to the existing 3D object, and reconstructed into 3D by referring to the existing 3D object from the current viewpoint. The incremental modeling enables a 3D object to be reconstructed from multiple sketching sessions from different viewpoints. However, the interface is limited to reconstructing trihedrons from sketches without T-junctions to avoid ambiguity in the hidden topology determination

Interpretation of overtracing freehand sketching for geometric shapes

This paper presents a novel method for interpreting overtracing freehand sketch. The overtracing strokes are interpreted as sketch content and are used to generate 2D geometric primitives. The approach consists of four stages: stroke classification, strokes grouping and fitting, 2D tidy-up with endpoint clustering and parallelism correction, and in-context interpretation. Strokes are first classified into lines and curves by a linearity test. It is followed by an innovative strokes grouping process that handles lines and curves separately. The grouped strokes are fitted with 2D geometry and further tidied-up with endpoint clustering and parallelism correction. Finally, the in-context interpretation is applied to detect incorrect stroke interpretation based on geometry constraints and to suggest a most plausible correction based on the overall sketch context. The interpretation ensures sketched strokes to be interpreted into meaningful output. The interface overcomes the limitation where only a single line drawing can be sketched out as in most existing sketching programs, meanwhile is more intuitive to the user

Phenotypic landscape inference reveals multiple evolutionary paths to C4_4 photosynthesis

C$_4$ photosynthesis has independently evolved from the ancestral C$_3$ pathway in at least 60 plant lineages, but, as with other complex traits, how it evolved is unclear. Here we show that the polyphyletic appearance of C$_4$ photosynthesis is associated with diverse and flexible evolutionary paths that group into four major trajectories. We conducted a meta-analysis of 18 lineages containing species that use C$_3$, C$_4$, or intermediate C$_3$-C$_4$ forms of photosynthesis to parameterise a 16-dimensional phenotypic landscape. We then developed and experimentally verified a novel Bayesian approach based on a hidden Markov model that predicts how the C$_4$ phenotype evolved. The alternative evolutionary histories underlying the appearance of C$_4$ photosynthesis were determined by ancestral lineage and initial phenotypic alterations unrelated to photosynthesis. We conclude that the order of C$_4$ trait acquisition is flexible and driven by non-photosynthetic drivers. This flexibility will have facilitated the convergent evolution of this complex trait

Analysis of instability patterns in non-Boussinesq mixed convection using a direct numerical evaluation of disturbance integrals

The Fourier integrals representing linearised disturbances arising from an initially localised source are evaluated numerically for natural and mixed convection flows between two differentially heated plates. The corresponding spatio-temporal instability patterns are obtained for strongly non-Boussinesq high-temperature convection of air and are contrasted to their Boussinesq counterparts. A drastic change in disturbance evolution scenarios is found when a large cross-channel temperature gradient leads to an essentially nonlinear variation of the fluid's transport properties and density. In particular, it is shown that non-Boussinesq natural convection flows are convectively unstable while forced convection flows can be absolutely unstable. These scenarios are opposite to the ones detected in classical Boussinesq convection. It is found that the competition between two physically distinct instability mechanisms which are due to the action of the shear and the buoyancy are responsible for such a drastic change in spatio-temporal characteristics of instabilities. The obtained numerical results confirm and complement semi-analytical conclusions of Suslov 2007 on the absolute/convective instability transition in non-Boussinesq mixed convection. Generic features of the chosen numerical approach are discussed and its advantages and shortcomings are reported

lynx1 Supports Neuronal Health in the Mouse Dorsal Striatum During Aging: an Ultrastructural Investigation

Nicotinic acetylcholine receptors have been shown to participate in neuroprotection in the aging brain. Lynx protein modulators dampen the activity of the cholinergic system through direct interaction with nicotinic receptors. Although lynx1 null mutant mice exhibit augmented learning and plasticity, they also exhibit macroscopic vacuolation in the dorsal striatum as they age, detectable at the optical microscope level. Despite the relevance of the lynx1 gene to brain function, little is known about the cellular ultrastructure of these age-related changes. In this study, we assessed degeneration in the dorsal striatum in 1-, 3-, 7-, and 13-month-old mice, using optical and transmission electron microscopy. We observed a loss of nerve fibers, a breakdown in nerve fiber bundles, and a loss of neuronal nuclei in the 13-month-old lynx1 null striatum. At higher magnification, these nerve fibers displayed intracellular vacuoles and disordered myelin sheaths. Few or none of these morphological alterations were present in younger lynx1 null mutant mice or in heterozygous lynx1 null mutant mice at any age. These data indicate that neuronal health can be maintained by titrating lynx1 dosage and that the lynx1 gene may participate in a trade-off between neuroprotection and augmented learning

The Modified Dynamic Gait Index and Limits of Stability in Myotonic Dystrophy Type 1

INTRODUCTION: The purpose of this study was to describe and compare the performance of balance and walking tests in relation to self-reported fall history in adults with myotonic dystrophy type 1 (DM1). METHODS: Twenty-two (13 male) participants with DM1 completed, a 6-month fall history questionnaire, the modified Dynamic Gait Index (mDGI), limits of stability (LoS) testing, and 10-m walking tests. RESULTS: Mean (SD) falls in 6 months was 3.7 (3.1), and 19 (86%) participants reported at least 1 fall. Significant differences in mDGI scores (P = 0.006) and 10-m fast walking gait velocity (P = 0.02) were found between those who had been classified as fallers and those who had been classified as nonfallers. Significant correlations were found between mDGI scores and 10-m walking time. DISCUSSION: Falls are common in DM1, and the mDGI may have potential to distinguish fallers from nonfallers, whereas the LoS failed to detect such impairment. Future studies should further explore use of the mDGI in DM1

Materialistic cues make us miserable: A meta‐analysis of the experimental evidence for the effects of materialism on individual and societal well‐being

open access articleConsumer‐oriented societies are awash with materialistic messages that link happiness and success to wealth and consumption. However, despite extensive research evidence that dispositional materialistic orientations are correlated with lower well‐being, the effects of materialistic cues on the well‐being of individuals and social groups have not been examined. The present research meta‐analytically reviews the experimental evidence for the causal effects of materialism on two dimensions of well‐being: (a) individual and (b) societal. We included 27 independent studies that met the inclusion criteria of priming materialism and measuring well‐being (N = 3,649), containing a total of 62 effect sizes. Multilevel modeling revealed that materialism has an effect on both individual (δ = −0.39) and societal well‐being (δ = −0.41), suggesting that materialistic cues cause lower well‐being. Moderation effects suggested that materialistic cues might have a higher effect on interpersonal well‐being than on self‐evaluation indicators. We discuss the limitations of the current evidence, highlight the research gaps and underdeveloped areas, and provide recommendations such as minimum sample size for future experimental work, since the advancement of this area will help us to gain a better understanding of the impact of consumer‐oriented societies on the well‐being of individuals and social groups

Fluidal pyroclasts reveal the intensity of peralkaline rhyolite pumice cone eruptions

This work is a contribution to the Natural Environment Research Council (NERC) funded RiftVolc project (NE/L013932/1, Rift volcanism: past, present and future) through which several of the authors are supported. In addition, Clarke was funded by a NERC doctoral training partnership grant (NE/L002558/1).Peralkaline rhyolites are medium to low viscosity, volatile-rich magmas typically associated with rift zones and extensional settings. The dynamics of peralkaline rhyolite eruptions remain elusive with no direct observations recorded, significantly hindering the assessment of hazard and risk. Here we describe uniquely-preserved, fluidal-shaped pyroclasts found within pumice cone deposits at Aluto, a peralkaline rhyolite caldera in the Main Ethiopian Rift. We use a combination of field-observations, geochemistry, X-ray computed microtomography (XCT) and thermal-modelling to investigate how these pyroclasts are formed. We find that they deform during flight and, depending on size, quench prior to deposition or continue to inflate then quench in-situ. These findings reveal important characteristics of the eruptions that gave rise to them: that despite the relatively low viscosity of these magmas, and similarities to basaltic scoria-cone deposits, moderate to intense, unstable, eruption columns are developed; meaning that such eruptions can generate extensive tephra-fall and pyroclastic density currents.Publisher PDFPeer reviewe

Optimal Baseline Prostate-Specific Antigen Level to Distinguish Risk of Prostate Cancer in Healthy Men Between 40 and 69 Years of Age

The present study evaluated optimal baseline prostate-specific antigen (PSA) level at different ages in order to determine the risk of developing prostate cancer (CaP). We analyzed 6,651 Korean men, aged 40-69 yr. The serum PSA levels for these men were measured at one institute from 2000 to 2004 and were determined to be between 0-4 ng/mL. Patients were divided into 4 groups of 25th-percentile intervals, based on initial PSA level. Of these, the group with an increased risk was selected, and the optimal value was determined by the maximal area under a receiver-operating characteristic curve within the selected group. The risk of CaP diagnosis was evaluated by Cox regression. The mean follow-up period was 8.3 yr. CaP was detected in 27 of the 6,651 subjects. CaP detection rate was increased according to age. The optimal PSA value to distinguish the risk of CaP was 2.0 ng/mL for 50- to 69-yr-olds. Patients with a baseline PSA level greater than the optimal value had a 27.78 fold increase in the prostate cancer risk. Baseline PSA values are useful for determining the risk of developing CaP in Korean men for 50- and 69-yr-old. We suggest that PSA testing intervals be modified based on their baseline PSA levels