2,200 research outputs found
Multivariate texture-based segmentation of remotely sensed imagery for extraction of objects and their uncertainty
In this study, a segmentation procedure is proposed, based on grey-level and multivariate texture to extract spatial objects from an image scene. Object uncertainty was quantified to identify transitions zones of objects with
indeterminate boundaries. The Local Binary Pattern (LBP) operator, modelling texture, was integrated into a hierarchical splitting segmentation to identify homogeneous texture regions in an image. We proposed a multivariate extension of the standard univariate LBP operator to describe colour texture. The paper is illustrated with two case studies. The first considers an image with a composite of texture regions. The two LBP operators provided good segmentation results on both grey-scale and colour textures, depicted by accuracy values of 96% and 98%, respectively. The second case study involved segmentation of coastal land cover objects from a multi-spectral Compact Airborne Spectral Imager (CASI) image, of a coastal area in the UK. Segmentation based on the univariate LBP measure
provided unsatisfactory segmentation results from a single CASI band (70% accuracy). A multivariate LBP-based segmentation of three CASI bands improved segmentation results considerably (77% accuracy). Uncertainty values for object building blocks provided valuable information for identification of object transition zones. We conclude that the (multivariate) LBP texture model in combination with a hierarchical splitting segmentation framework is suitable for identifying objects and for quantifying their uncertainty
Living donor liver transplantation for neonatal hemochromatosis using non-anatomically resected segments II and III: a case report
<p>Abstract</p> <p>Introduction</p> <p>Neonatal hemochromatosis is the most common cause of liver failure and liver transplantation in the newborn. The size of the infant determines the liver volume that can be transplanted safely without incurring complications arising from a large graft. Transplantation of monosegments II or III is a standard method for the newborns with liver failure.</p> <p>Case presentation</p> <p>A three-week old African-American male neonate was diagnosed with acute liver failure secondary to neonatal hemochromatosis. Living-related liver transplantation was considered after the failure of intensive medical therapy. Intra-operatively a non-anatomical resection and transplantation of segments II and III was performed successfully. The boy is growing normally two years after the transplantation.</p> <p>Conclusion</p> <p>Non-anatomical resection and transplantation of liver segments II and III is preferred to the transplantation of anatomically resected monosegements, especially when the left lobe is thin and flat. It allows the use of a reduced-size donor liver with intact hilar structures and outflow veins. In an emergency, living-related liver transplantation should be offered to infants with liver failure secondary to neonatal hemochromatosis who fail to respond to medical treatment.</p
The geography of recent genetic ancestry across Europe
The recent genealogical history of human populations is a complex mosaic
formed by individual migration, large-scale population movements, and other
demographic events. Population genomics datasets can provide a window into this
recent history, as rare traces of recent shared genetic ancestry are detectable
due to long segments of shared genomic material. We make use of genomic data
for 2,257 Europeans (the POPRES dataset) to conduct one of the first surveys of
recent genealogical ancestry over the past three thousand years at a
continental scale. We detected 1.9 million shared genomic segments, and used
the lengths of these to infer the distribution of shared ancestors across time
and geography. We find that a pair of modern Europeans living in neighboring
populations share around 10-50 genetic common ancestors from the last 1500
years, and upwards of 500 genetic ancestors from the previous 1000 years. These
numbers drop off exponentially with geographic distance, but since genetic
ancestry is rare, individuals from opposite ends of Europe are still expected
to share millions of common genealogical ancestors over the last 1000 years.
There is substantial regional variation in the number of shared genetic
ancestors: especially high numbers of common ancestors between many eastern
populations likely date to the Slavic and/or Hunnic expansions, while much
lower levels of common ancestry in the Italian and Iberian peninsulas may
indicate weaker demographic effects of Germanic expansions into these areas
and/or more stably structured populations. Recent shared ancestry in modern
Europeans is ubiquitous, and clearly shows the impact of both small-scale
migration and large historical events. Population genomic datasets have
considerable power to uncover recent demographic history, and will allow a much
fuller picture of the close genealogical kinship of individuals across the
world.Comment: Full size figures available from
http://www.eve.ucdavis.edu/~plralph/research.html; or html version at
http://ralphlab.usc.edu/ibd/ibd-paper/ibd-writeup.xhtm
Hierarchical information clustering by means of topologically embedded graphs
We introduce a graph-theoretic approach to extract clusters and hierarchies
in complex data-sets in an unsupervised and deterministic manner, without the
use of any prior information. This is achieved by building topologically
embedded networks containing the subset of most significant links and analyzing
the network structure. For a planar embedding, this method provides both the
intra-cluster hierarchy, which describes the way clusters are composed, and the
inter-cluster hierarchy which describes how clusters gather together. We
discuss performance, robustness and reliability of this method by first
investigating several artificial data-sets, finding that it can outperform
significantly other established approaches. Then we show that our method can
successfully differentiate meaningful clusters and hierarchies in a variety of
real data-sets. In particular, we find that the application to gene expression
patterns of lymphoma samples uncovers biologically significant groups of genes
which play key-roles in diagnosis, prognosis and treatment of some of the most
relevant human lymphoid malignancies.Comment: 33 Pages, 18 Figures, 5 Table
Evaluation of the effects of photodynamic therapy with phosphorus 31 magnetic resonance spectroscopy
Computational Modelling of Patella Femoral Kinematics During Gait Cycle and Experimental Validation
The effect of loading and boundary conditions on patellar mechanics is significant due to the complications arising in patella femoral joints during total knee replacements. To understand the patellar mechanics with respect to loading and motion, a computational model representing the patella femoral joint was developed and validated against experimental results. The computational model was created in IDEAS NX and simulated in MSC ADAMS/VIEW software. The results obtained in the form of internal external rotations and anterior posterior displacements for a new and experimentally simulated specimen for patella femoral joint under standard gait condition were compared with experimental measurements performed on the Leeds ProSim knee simulator. A good overall agreement between the computational prediction and the experimental data was obtained for patella femoral kinematics. Good agreement between the model and the past studies was observed when the ligament load was removed and the medial lateral displacement was constrained. The model is sensitive to ±5 % change in kinematics, frictional, force and stiffness coefficients and insensitive to time step
Author Correction: The mTORC1/4E-BP1 axis represents a critical signaling node during fibrogenesis
Correction to: Nature Communications https://doi.org/10.1038/s41467-018-07858-8, published online 2 January 2019
Primary chemotherapy with gemcitabine, epirubicin and taxol (GET) in operable breast cancer: a phase II study
This trial was conducted to assess the activity and tolerability of the gemcitabine, epirubicin, taxol triplet combination in patients with operable breast cancer. After core biopsy, 43 women with stage II–IIIA breast cancer were treated with gemcitabine 1000 mg m−2 over 30 min on days 1 and 4, epirubicin 90 mg m−2 as an intravenous bolus on day 1, and taxol 175 mg m−2 as a 3-h infusion on day 1, every 21 days for four cycles. The primary end point was the percentage of pathological complete responses (pCR) in the breast; secondary end points were tolerability, clinical response rates, overall and progression-free survival, tumour biomarkers before and after primary chemotherapy (PCT). All patients were included in safety and survival analyses; 41 eligible patients were evaluated for response. The overall clinical response rate was 87.8% (95% CI 77.8–97.8), with 26.8% complete responses (95% CI 13.3–40.3). A pCR in the breast was observed in six patients (14.6%; 95% CI 3.8–25.4); 15 patients (36.6%; 95% CI 21.9–51.3) had negative axillary lymph nodes. Grade 4 neutropenia was observed in 67.4% of the patients; febrile neutropenia occurred in 1.9% of cycles (granulocyte colony-stimulating factor was used in 3.2% of the cycles to shorten the duration of neutropenia). A statistically significant difference between Mib-1 at baseline (⩾20% in 71.4% of the patients) and at definitive surgery (28.6%, P<0.05) was observed. The gemcitabine, epirubicin, taxol regimen is active and well tolerated as PCT for operable breast cancer. This combination allows the administration of full doses of active agents with a low incidence of febrile neutropenia
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