394 research outputs found
Improved Depth Map Estimation from Stereo Images based on Hybrid Method
In this paper, a stereo matching algorithm based on image segments is presented. We propose the hybrid segmentation algorithm that is based on a combination of the Belief Propagation and Mean Shift algorithms with aim to refine the disparity and depth map by using a stereo pair of images. This algorithm utilizes image filtering and modified SAD (Sum of Absolute Differences) stereo matching method. Firstly, a color based segmentation method is applied for segmenting the left image of the input stereo pair (reference image) into regions. The aim of the segmentation is to simplify representation of the image into the form that is easier to analyze and is able to locate objects in images. Secondly, results of the segmentation are used as an input of the local window-based matching method to determine the disparity estimate of each image pixel. The obtained experimental results demonstrate that the final depth map can be obtained by application of segment disparities to the original images. Experimental results with the stereo testing images show that our proposed Hybrid algorithm HSAD gives a good performance
Im2Vec: Synthesizing Vector Graphics without Vector Supervision
Vector graphics are widely used to represent fonts, logos, digital artworks, and graphic designs. But, while a vast body of work has focused on generative algorithms for raster images, only a handful of options exists for vector graphics. One can always rasterize the input graphic and resort to image-based generative approaches, but this negates the advantages of the vector representation. The current alternative is to use specialized models that require explicit supervision on the vector graphics representation at training time. This is not ideal because large-scale high quality vector-graphics datasets are difficult to obtain. Furthermore, the vector representation for a given design is not unique, so models that supervise on the vector representation are unnecessarily constrained. Instead, we propose a new neural network that can generate complex vector graphics with varying topologies, and only requires indirect supervision from readily-available raster training images (i.e., with no vector counterparts). To enable this, we use a differentiable rasterization pipeline that renders the generated vector shapes and composites them together onto a raster canvas. We demonstrate our method on a range of datasets, and provide comparison with state-of-the-art SVG-VAE and DeepSVG, both of which require explicit vector graphics supervision. Finally, we also demonstrate our approach on the MNIST dataset, for which no groundtruth vector representation is available. Source code, datasets, and more results are available at geometry.cs.ucl.ac.uk/projects/2021/Im2Vec
Comparison of semen characteristics and histological structure of the testis from transgenic and non-transgenic rabbits
[EN] The aim of this study was to compare semen characteristics including sperm quantity, quality, and abnormalities, as well as histological structure of the testis of three-year old transgenic (human clotting factor, hFVIII, gene) and nontransgenic rabbits. For the experiment, 10 transgenic rabbits of F2 and F3 generations and 10 randomly selected non-transgenic males of the same breed and age were used as controls. All males were housed in individual cages, under a the same environmental conditions: photoperiod (14L:10D), temperature (18-20°C), and humidity (65-70%). Semen samples, collected once a week for 20 wk from each control and transgenic male, were analyzed by computer assited semen analysis within a few minutes following natural ejaculation into an artificial vagina. Concentration of spermatozoa was higher in the transgenic than in the non-transgenic group (P<0.001; 316.6±148.8 and 126.7±64.4¿106/ mL, respectively). Significant differences (P<0.1) between transgenic and non-transgenic males were observed also in spermatozoa motility (63.08 vs. 32.60%). Significantly higher (P<0.05) relative volume (8.08±2.89%) and diameter of testicular lumen (36.89±23.11 ¿m) were found in the transgenic animals compared to control animals (16.69±4.70%, 53.89±25.42 ¿m). Our results show that spermatozoa parameters and histological structure of the testis can be used for the characterization of male reproductive traits of older transgenic rabbits.This work was supported by the grant No: 2003 SP51/028 09 00/028 09 03 coordinated by the Slovak Academy of Science and by the grant of Ministry of Agriculture Slovak Republic (RÚVV 07-012). All experiments were approved according to ethical permission No. SK P 28004. We are grateful to Dr. Shoubadeep Roychoudhury for the English correction.Lukac, N.; Massanyi, P.; Flesarova, S.; Danko, J.; Makarevich, A.; Chrenek, P. (2009). Comparison of semen characteristics and histological structure of the testis from transgenic and non-transgenic rabbits. World Rabbit Science. 17(4):221-226. https://doi.org/10.4995/wrs.2009.64722122617
Impulsive noise removal from color images with morphological filtering
This paper deals with impulse noise removal from color images. The proposed
noise removal algorithm employs a novel approach with morphological filtering
for color image denoising; that is, detection of corrupted pixels and removal
of the detected noise by means of morphological filtering. With the help of
computer simulation we show that the proposed algorithm can effectively remove
impulse noise. The performance of the proposed algorithm is compared in terms
of image restoration metrics and processing speed with that of common
successful algorithms.Comment: The 6th international conference on analysis of images, social
networks, and texts (AIST 2017), 27-29 July, 2017, Moscow, Russi
Effect of dietary supplementation with seaweed and polyphenols mixture on antioxidant status, concentration and motility of rabbit spermatozoa
In recent years, many studies have been focused on natural substances that could have effect on health of animals. We investigated effect of extract consisting mainly of polyphenols, brown algae and plant polysaccharides on the reproduction potential of male rabbits (New Zealand white breed) during 60 days long dietary experiment. The rabbits were divided into three groups. Control was fed a basal diet, whereas the second and third group were supplemented with seaweed and polyphenols mixture: T1 = 0.3% and T2 = 0.6% respectively. We observed that sperm concentration in both experimental groups increased in comparison to the control group. Results of the CASA analysis showed enhanced motility (C = 85.09±7.53%, T1 = 87.21±8.25%, T2 = 89.38±8.02%) and progressive motility (C = 74.28±12.6%, T1 = 79.07±13.89%, T2 = 81.28±11.37%) in experimental groups supplemented with combination of algae and polyphenols in comparison with the control group. While monitoring ferric reducing ability of plasma (FRAP), we found the highest value in T1 group, changes were insignificat. An increase in GPx activity was measured in experimental groups in comparison with the control group with major difference in T1 group. In experimental groups, we determined an increase in activity of superoxide dismutase (SOD) in comparison with control group, the difference was significant in T2 group (C = 0.26±0.11 U/mg TP; T2 = 0.31±0.09 U/mg TP). In conclusion, our studies suggest that dietary supplementation with brown seaweed and plant polyphenols mixture may be potentially useful for enhancement of sperm motility and protection against oxidative stress
Endocrine Disruption by Heavy Metals on Steroidogenesis in Model Systems
In this study human adrenocortical carcinoma cell line NCI-H295R was used as an in vitro biological model to study the effect of heavy metals on steroidogenesis. The cell cultures were exposed to different concentrations of cadmium (1.90; 3.90; 7.80; 15.60; 31.20; 62.50 μM of CdCl2), mercury (1.0; 5.0; 25; 50; 100 μM of HgCl2), nickel (3.90; 7.80; 15.60; 31.20; 62.50; 125; 250; 500 μM of NiCl2) and compared to control. Cell viability was measured by the metabolic activity (MTT) assay for estimation of mitochondria structural integrity. Quantification of sexual steroid production directly from aliquots of the medium was performed by enzyme linked immunosorbent assay (ELISA). Cadmium decreased the release of progesterone and testosterone already at a very low concentration (1.90 μM) of CdCl2, while the cell viability remained relatively high (> 75%) up to 7.80 μM of CdCl2 and significantly (P<0.01) decreased at 15.60 μM and higher concentrations of CdCl2. Concentration-dependent depression in testosterone production was detected particularly for higher concentration of HgCl2. Progesterone production was also decreased, but at the lower concentrations (1.0 and 5.0 μM) of HgCl2 this decline was lower compared to depression of testosterone. The cell viability significantly decreased at 25 μM and higher concentration of HgCl2. Results of the our study indicate dose dependent decreases in both sexual steroid hormones by NCI-H295R cell culture following a 48 h in vitro NiCl2 exposure. The lowest concentration of progesterone was significantly (P<0.01) detected in groups with the higher doses (≥ 500 μM) of NiCl2, which elicited significant cytotoxic effect. The testosterone production was decreased as well, but this decline was more pronounced compared to depression of progesterone. These results suggest that heavy metals have detrimental effects on steroid hormone synthesis even at very low concentrations and consecutively on reproductive physiology
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Biotic carbon feedbacks in a materially-closed soil-vegetation-atmosphere system
The magnitude and direction of the coupled feedbacks between the biotic and abiotic components of the terrestrial carbon cycle is a major source of uncertainty in coupled climate–carbon-cycle models1, 2, 3. Materially closed, energetically open biological systems continuously and simultaneously allow the two-way feedback loop between the biotic and abiotic components to take place4, 5, 6, 7, but so far have not been used to their full potential in ecological research, owing to the challenge of achieving sustainable model systems6, 7. We show that using materially closed soil–vegetation–atmosphere systems with pro rata carbon amounts for the main terrestrial carbon pools enables the establishment of conditions that balance plant carbon assimilation, and autotrophic and heterotrophic respiration fluxes over periods suitable to investigate short-term biotic carbon feedbacks. Using this approach, we tested an alternative way of assessing the impact of increased CO2 and temperature on biotic carbon feedbacks. The results show that without nutrient and water limitations, the short-term biotic responses could potentially buffer a temperature increase of 2.3 °C without significant positive feedbacks to atmospheric CO2. We argue that such closed-system research represents an important test-bed platform for model validation and parameterization of plant and soil biotic responses to environmental changes
A quantum genetic algorithm with quantum crossover and mutation operations
In the context of evolutionary quantum computing in the literal meaning, a
quantum crossover operation has not been introduced so far. Here, we introduce
a novel quantum genetic algorithm which has a quantum crossover procedure
performing crossovers among all chromosomes in parallel for each generation. A
complexity analysis shows that a quadratic speedup is achieved over its
classical counterpart in the dominant factor of the run time to handle each
generation.Comment: 21 pages, 1 table, v2: typos corrected, minor modifications in
sections 3.5 and 4, v3: minor revision, title changed (original title:
Semiclassical genetic algorithm with quantum crossover and mutation
operations), v4: minor revision, v5: minor grammatical corrections, to appear
in QI
Effect of Donor Simvastatin Treatment on Gene Expression Profiles in Human Cardiac Allografts during Ischemia-Reperfusion Injury
Purpose Numerous studies have shown that statin therapy initiated early after heart transplantation has beneficial effects on the development of cardiac allograft vasculopathy. Recently, we were able to show in a randomized clinical trial that simvastatin treatment of brain-dead donors conditions the heart transplant to withstand ischemia-reperfusion injury and to reduce the need for rejection treatments early after transplantation. In this study, we analyzed myocardial gene expression profiles in cardiac allografts after donor simvastatin treatment. Methods 84 heart transplant donors received 80 mg of simvastatin via nasogastric tube (n=42), or no treatment (n=42) in a prospective, double-blinded randomized controlled trial. Transmural Tru-Cut biopsies were taken from the apex of left ventricle of the donor heart immediately before reperfusion and 1 hour after reperfusion. 20 heart biopsies from donors without treatment and 20 heart biopsies from donors with simvastatin treatment will be analyzed with RNA sequencing. Results The preliminary analysis of RNA sequencing data from myocardial biopsies revealed altogether 137 significantly differentially expressed genes in all pairwise comparisons. The overall biological functions of these genes were related to gene ontology terms such as response to toxic substance, leukocyte migration, neutrophil mediated immunity, response to lipopolysaccharide, and response to oxidative stress. At the KEGG pathway level, our results indicated alterations in IL-17, TNF, MAPK and the AGE-RAGE signaling pathways. Conclusion We have shown in previous studies that donor simvastatin treatment induces protective effects against IRI in heart transplant recipients. In this study, we were able to detect significantly differentially expressed genes related to effects of simvastatin treatment. In order to single out genes that show beneficial effects of simvastatin treatment, further analysis will be conducted by exploring gene expression changes in specific biological functional categories, such as interleukin signaling and neutrophil degranulation. The complete analysis will be presented at the ISHLT 2019 congress.Peer reviewe
Defects in High Entropy Alloy HfNbTaTiZr Prepared by High Pressure Torsion
High entropy alloy HfNbTaTiZr was successfully processed by severe plastic deformation using high pressure torsion (HPT) and ultrafine grained microstructure was achieved. The microstructure of HPT-deformed HfNbTaTiZr alloy was characterized by X-ray diffraction and compared with conventionally cast ingots. The lattice defects introduced by HPT processing were characterized by positron annihilation spectroscopy. The X-ray diffraction profiles of HTP-deformed samples were extremely broadened due to small sizes of coherently diffracting domains and a high microstrain introduced by severe plastic deformation.11Ysciescopu
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