154 research outputs found

    RLFC: Random Access Light Field Compression using Key Views and Bounded Integer Encoding

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    We present a new hierarchical compression scheme for encoding light field images (LFI) that is suitable for interactive rendering. Our method (RLFC) exploits redundancies in the light field images by constructing a tree structure. The top level (root) of the tree captures the common high-level details across the LFI, and other levels (children) of the tree capture specific low-level details of the LFI. Our decompressing algorithm corresponds to tree traversal operations and gathers the values stored at different levels of the tree. Furthermore, we use bounded integer sequence encoding which provides random access and fast hardware decoding for compressing the blocks of children of the tree. We have evaluated our method for 4D two-plane parameterized light fields. The compression rates vary from 0.08 - 2.5 bits per pixel (bpp), resulting in compression ratios of around 200:1 to 20:1 for a PSNR quality of 40 to 50 dB. The decompression times for decoding the blocks of LFI are 1 - 3 microseconds per channel on an NVIDIA GTX-960 and we can render new views with a resolution of 512X512 at 200 fps. Our overall scheme is simple to implement and involves only bit manipulations and integer arithmetic operations.Comment: Accepted for publication at Symposium on Interactive 3D Graphics and Games (I3D '19

    Consumption-as-usual instead of ceteris paribus assumption for demand: Integration of potential rebound effects into LCA

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    Background, aims, and scope: Life cycle assessment (LCA) according to ISO 14040 standard (ISO-LCA) is applied to assess the environmental impact per functional unit of new or modified products. However, new or modified products can also induce demand changes—so-called rebound effects. If overall environmental impact is of interest, there is a need to assess the potential magnitude of such rebound effects and to allow recommendations on how to mitigate these effects. To do so, this study proposes to complement the constant demand assumption (implicitly assumed by the ISO-LCA), commonly known as the ceteris paribus assumption, with a consumption-as-usual assumption allowing a systematic stepwise inclusion of rebound effects. Materials and methods: We base our results on a formal description of household consumption. To indicate the relevance of the proposed integration of rebound effects, different comparative LCAs are reviewed and the concept is applied to mobility as illustrative examples. Results: Based on a description of household demand and consumption feedback loops, we propose the consumption-as-usual concept, which in contrast to the constant demand assumption assumes that (1) the use of household resources for consumption does not change and (2) preferences remain the same. Household resources for example are purchasing power (we assume that households do not work less), time, and living space. We outline how this concept allows integrating potential rebound effects into ISO-LCA by considering three different cases of reallocating freed household resources. To illustrate the use of the consumption-as-usual concept, we draw implications for different comparative LCAs from the literature and illustrate cases with income and time rebound for different personal travel modes. Discussion: The consumption-as-usual concept is applicable to a broad range of product modifications and allows an important complementation of the LCA regarding rebound effects. For products with various changes in the need for household resources, the assessment becomes however a challenging task. The limits of the consumption-as-usual concept are mainly given by its two underlying assumptions. Therefore, new or modified products with the potential to change consumer preferences or even the amount of household resources used for consumption go beyond this concept. Conclusions: The integration of rebound effects is feasible for many comparative LCAs. It helps in increasing the reliability of the assessment of overall environmental impact reduction through new or modified products. In addition, a basis is provided with which to mitigate rebound effects and give appropriate recommendations to product users. Recommendations and perspectives: Potential rebound effects should be included in LCA in order to guide consumers and policy towards sustainable consumption. We recommend the consumption-as-usual concept for this purpose. To predict rebound effects under consumption as usual instead of outlining potential amplitudes, further research on household preferences is needed and an optimisation model should be applied for household consumption. However, even if data are available for such a prediction, the assessment of potential rebound effects is still recommended in order to recognise dangers and opportunities in consumption change

    Report from the PredictER Expert Panel Meeting, November 2, 2007

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    On November 2, 2007, the Indiana University Center for Bioethics convened an expert panel on predictive health research (PHR) as part of the Center’s Program in Predictive Health Ethics Research (http://www.bioethics.iu.edu/predicter.asp) which is supported by a grant from the Richard M. Fairbanks Foundation. The goal of this meeting was to identify the major obstacles and opportunities for engaging the community in PHR. PredictER intends to use the results of this meeting as a first step toward more fully engaging the Indianapolis community in discussions about PHR.Richard M. Fairbanks Foundatio

    Energy-momentum tensor form factors of the nucleon in nuclear matter

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    The nucleon form factors of the energy-momentum tensor are studied in nuclear medium in the framework of the in-medium modified Skyrme model. We obtain a negative D-term, in agreement with results from other approaches, and find that medium effects make the value of d_1 more negative.Comment: 9 pages, 11 figures. Some typos were removed and one reference was adde

    The secretion inhibitor Exo2 perturbs trafficking of Shiga toxin between endosomes and the trans-Golgi network

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    The small-molecule inhibitor Exo2 {4-hydroxy-3-methoxy-(5,6,7,8-tetrahydrol[1]benzothieno[2,3-d]pyrimidin-4-yl)hydraz-one benzaldehyde} has been reported to disrupt the Golgi apparatus completely and to stimulate Golgi–ER (endoplasmic reticulum) fusion in mammalian cells, akin to the well-characterized fungal toxin BFA (brefeldin A). It has also been reported that Exo2 does not affect the integrity of the TGN (trans-Golgi network), or the direct retrograde trafficking of the glycolipid-binding cholera toxin from the TGN to the ER lumen. We have examined the effects of BFA and Exo2, and found that both compounds are indistinguishable in their inhibition of anterograde transport and that both reagents significantly disrupt the morphology of the TGN in HeLa and in BS-C-1 cells. However, Exo2, unlike BFA, does not induce tubulation and merging of the TGN and endosomal compartments. Furthermore, and in contrast with its effects on cholera toxin, Exo2 significantly perturbs the delivery of Shiga toxin to the ER. Together, these results suggest that the likely target(s) of Exo2 operate at the level of the TGN, the Golgi and a subset of early endosomes, and thus Exo2 provides a more selective tool than BFA for examining membrane trafficking in mammalian cells

    Association of pulmonary vein isolation and major cardiovascular events in patients with atrial fibrillation.

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    BACKGROUND Patients with atrial fibrillation (AF) face an increased risk of adverse cardiovascular events. Evidence suggests that early rhythm control including AF ablation may reduce this risk. METHODS To compare the risks for cardiovascular events in AF patients with and without pulmonary vein isolation (PVI), we analysed data from two prospective cohort studies in Switzerland (n = 3968). A total of 325 patients who had undergone PVI during a 1-year observational period were assigned to the PVI group. Using coarsened exact matching, 2193 patients were assigned to the non-PVI group. Outcomes were all-cause mortality, hospital admission for acute heart failure, a composite of stroke, transient ischemic attack and systemic embolism (Stroke/TIA/SE), myocardial infarction (MI), and bleedings. We calculated multivariable adjusted Cox proportional-hazards models. RESULTS Overall, 2518 patients were included, median age was 66 years [IQR 61.0, 71.0], 25.8% were female. After a median follow-up time of 3.9 years, fewer patients in the PVI group died from any cause (incidence per 100 patient-years 0.64 versus 1.87, HR 0.39, 95%CI 0.19-0.79, p = 0.009) or were admitted to hospital for acute heart failure (incidence per 100 patient-years 0.52 versus 1.72, HR 0.44, 95%CI 0.21-0.95, p = 0.035). There was no significant association between PVI and Stroke/TIA/SE (HR 0.94, 95%CI 0.52-1.69, p = 0.80), MI (HR 0.43, 95%CI 0.11-1.63, p = 0.20) or bleeding (HR 0.75, 95% CI 0.50-1.12, p = 0.20). CONCLUSIONS In our matched comparison, patients in the PVI group had a lower incidence rate of all-cause mortality and hospital admission for acute heart failure compared to the non-PVI group. CLINICALTRIALS GOV IDENTIFIER NCT02105844, April 7th 2014
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