385 research outputs found
The Business Model: A Means to Comprehend the Management and Business Context of Information and Communication Technology
This paper presents a conceptual business model, which aims to improve the understanding of the business context of Information and Communication Technologies (ICT). We argue that research into how ICT generates economic value is limitedly valid due to lacking comprehensive knowledge of strategy theory and lacking abilities to integrate strategy perspectives, and the fragmentation of strategy theory. We discuss the main strategy perspectives as well as ICT research within each of these perspectives and conclude that in order to improve the understanding of the ways in which ICT generates value, research must integrate different perspectives. We also review some of the new ebusiness texts that addresses business models. The business model is broader than any individual strategy perspective (such as Industrial Organisation, the Resource-Based View or the Strategy Process Perspective) and includes market factors, offering, activities, organisation and resource bases as well as longitudinal management processes. In addition, we illustrate how the management and business context of ICT (such as ERP and CRM systems) can be viewed through the business model
MobileNeRF: Exploiting the Polygon Rasterization Pipeline for Efficient Neural Field Rendering on Mobile Architectures
Neural Radiance Fields (NeRFs) have demonstrated amazing ability to
synthesize images of 3D scenes from novel views. However, they rely upon
specialized volumetric rendering algorithms based on ray marching that are
mismatched to the capabilities of widely deployed graphics hardware. This paper
introduces a new NeRF representation based on textured polygons that can
synthesize novel images efficiently with standard rendering pipelines. The NeRF
is represented as a set of polygons with textures representing binary opacities
and feature vectors. Traditional rendering of the polygons with a z-buffer
yields an image with features at every pixel, which are interpreted by a small,
view-dependent MLP running in a fragment shader to produce a final pixel color.
This approach enables NeRFs to be rendered with the traditional polygon
rasterization pipeline, which provides massive pixel-level parallelism,
achieving interactive frame rates on a wide range of compute platforms,
including mobile phones.Comment: CVPR 2023. Project page: https://mobile-nerf.github.io, code:
https://github.com/google-research/jax3d/tree/main/jax3d/projects/mobilener
On the tidal environment of an outwardly migrating F ring
Saturn’s F-ring is a unique narrow ring that lies radially close to the tidally disruptive Roche limit of Saturn for water ice. Significant work has been done on the system that shows it to be one of the most dynamic places in the Solar System. Aggregates fortunate enough to form constantly battle against the strong tidal forces of Saturn and the nearby moons Prometheus and Pandora, which act to gravitationally stir up ring material. Planetary rings are also known to radially spread, with the outer ring edge migrating outwards. As the F ring lies at the edge of the main rings, we investigate the effect of an outwardly migrated F ring and its interaction with Prometheus. For each model with decreasing local tidal environment, an increase in maximum number density of particles at the channel edges is observed. In the same locations as particles with maximum number densities, radial velocity dispersion's are observed to fall below escape velocities of a 150m icy moonlet (<10 cm s^(-1)), and are gravitationally unstable with Toomre parameters Q<2. Additionally, in locations of the ring where Q<2 is observed, more particles are seen to fall below or close to critical values as the radial location of the ring increases
Does the core circadian clock in the moss Physcomitrella patens (Bryophyta) comprise a single loop?
<p>Abstract</p> <p>Background</p> <p>The endogenous circadian clock allows the organism to synchronize processes both to daily and seasonal changes. In plants, many metabolic processes such as photosynthesis, as well as photoperiodic responses, are under the control of a circadian clock. Comparative studies with the moss <it>Physcomitrella patens </it>provide the opportunity to study many aspects of land plant evolution. Here we present a comparative overview of clock-associated components and the circadian network in the moss <it>P. patens</it>.</p> <p>Results</p> <p>The moss <it>P. patens </it>has a set of conserved circadian core components that share genetic relationship and gene expression patterns with clock genes of vascular plants. These genes include Myb-like transcription factors <it>PpCCA1a </it>and <it>PpCCA1b</it>, pseudo-response regulators <it>PpPRR1-4</it>, and regulatory elements <it>PpELF3</it>, <it>PpLUX </it>and possibly <it>PpELF4</it>. However, the moss lacks homologs of <it>AtTOC1</it>, <it>AtGI </it>and the <it>AtZTL</it>-family of genes, which can be found in all vascular plants studied here. These three genes constitute essential components of two of the three integrated feed-back loops in the current model of the Arabidopsis circadian clock mechanism. Consequently, our results suggest instead a single loop circadian clock in the moss. Possibly as a result of this, temperature compensation of core clock gene expression appears to be decreased in <it>P. patens.</it></p> <p>Conclusions</p> <p>This study is the first comparative overview of the circadian clock mechanism in a basal land plant, the moss <it>P. patens</it>. Our results indicate that the moss clock mechanism may represent an ancestral state in contrast to the more complex and partly duplicated structure of subsequent land plants. These findings may provide insights into the understanding of the evolution of circadian network topology.</p
Soft Palate Modification Using a Collagen Crosslinking Reagent for Equine Dorsal Displacement of the Soft Palate and Other Upper Airway Breathing Disorders
The mechanical properties of the soft palate can be associated with breathing abnormalities. Dorsal displacement of the soft palate (DDSP) is a naturally occurring equine soft palate disorder caused by displacement of the caudal edge of the soft palate. Snoring and a more serious, sometimes life-threatening, condition called obstructive sleep apnea (OSA) are forms of sleep-related breathing disorders in humans which may involve the soft palate. The goal of this study was to investigate the effect of injecting the protein crosslinker genipin into the soft palate to modify its mechanical properties for the treatment of equine DDSP with potential implications for the treatment of snoring and OSA in humans. Ex vivo experiments consisted of mechanical testing and a wind tunnel study to examine the effect of genipin on the mechanical properties, displacement, and vibration of equine soft palates. A pilot in vivo study was completed using DDSP and control horses to test the safety and effectiveness of injecting a genipin reagent into the soft palate. The wind tunnel testing demonstrated a greater than 50% decrease in transient deformation and a greater than 33% decrease in steady-state vibrations for all doses of genipin tested. Ultimate tensile stress, yield stress, and Young’s modulus were higher in the genipin-treated distal soft palate specimens by 52%, 53%, and 63%, respectively. The pilot in vivo study showed a reduction of snoring loudness in all DDSP horses and elimination of DDSP in at least one of three horses. The difficulty of using a 1-meter-long endoscopic injection needle contributed to a consistent overinjection of the equine soft palates, causing excessive stretching (pillowing) and related degradation of the tissue. These ex vivo and in vivo results demonstrated reduced vibration amplitude and flaccidity and increased strength of genipin-treated soft palates, suggesting that genipin crosslinking could become an effective and safe treatment for soft palate related breathing abnormalities
Forces on nascent polypeptides during membrane insertion and translocation via the Sec translocon
During ribosomal translation, nascent polypeptide chains (NCs) undergo a variety of physical processes that determine their fate in the cell. This study utilizes a combination of arrest peptide (AP) experiments and coarse-grained molecular dynamics (CGMD) to measure and elucidate the molecular origins of forces that are exerted on NCs during co-translational membrane insertion and translocation via the Sec translocon. The approach enables deconvolution of force contributions from NC-translocon and NC-ribosome interactions, membrane partitioning, and electrostatic coupling to the membrane potential. In particular, we show that forces due to NC-lipid interactions provide a read-out of conformational changes in the Sec translocon, demonstrating that lateral gate opening only occurs when a sufficiently hydrophobic segment of NC residues reaches the translocon. The combination of experiment and theory introduced here provides a detailed picture of the molecular interactions and conformational changes during ribosomal translation that govern protein biogenesis
A new method for determination of varicella-zoster virus immunoglobulin G avidity in serum and cerebrospinal fluid
BACKGROUND: Avidity determination of antigen-specific immunoglobulin G (IgG) antibodies is an established serological method to differentiate acute from past infections. In order to compare the avidity of varicella-zoster virus (VZV) IgG in pairs of serum and cerebrospinal fluid (CSF) samples, we developed a new technique of avidity testing, the results of which are not influenced by the concentration of specific IgG. METHODS: The modifications introduced for the new VZV IgG avidity method included the use of urea hydrogen peroxide as denaturing reagent, the adaptation of the assay parameters in order to increase the sensitivity for the detection of low-level VZV IgG in CSF, and the use of a new calculation method for avidity results. The calculation method is based on the observation that the relationship between the absorbance values of the enzyme immunoassays with and without denaturing washing step is linear. From this relationship, a virtual absorbance ratio can be calculated. To evaluate the new method, a panel of serum samples from patients with acute and past VZV infection was tested as well as pairs of serum and CSF. RESULTS: For the serum panel, avidity determination with the modified assay gave results comparable to standard avidity methods. Based on the coefficient of variation, the new calculation method was superior to established methods of avidity calculation. CONCLUSIONS: The new avidity method permits a meaningful comparison of VZV IgG avidity in serum and CSF and should be of general applicability for easy determination of avidity results, which are not affected by the concentration of specific IgG
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