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Spatial modeling

Jens Göttler, Mathias Lukas, Anne Kluge, Stephan Kaczmarz, Jens Gempt, Florian Ringel, Mona Mustafa, Bernhard Meyer, Claus Zimmer, Markus Schwaiger, Stefan Förster, Christine Preibisch, Thomas Pyka
PURPOSE: (18)F-fluorethyltyrosine-(FET)-PET and MRI-based relative cerebral blood volume (rCBV) have both been used to characterize gliomas. Recently, inter-individual correlations between peak static FET-uptake and rCBV have been reported. Herein, we assess the local intra-lesional relation between FET-PET parameters and rCBV. METHODS: Thirty untreated glioma patients (27 high-grade) underwent simultaneous PET/MRI on a 3 T hybrid scanner obtaining structural and dynamic susceptibility contrast sequences...
December 2, 2016: European Journal of Nuclear Medicine and Molecular Imaging
Marc D Ryser, Walter T Lee, Neal E Ready, Kevin Z Leder, Jasmine Foo
High rates of local recurrence in tobacco-related head and neck squamous cell carcinoma (HNSCC) are commonly attributed to unresected fields of precancerous tissue. Because they are not easily detectable at the time of surgery without additional biopsies, there is a need for noninvasive methods to predict the extent and dynamics of these fields. Here, we developed a spatial stochastic model of tobacco-related HNSCC at the tissue level and calibrated the model using a Bayesian framework and population-level incidence data from the Surveillance, Epidemiology, and End Results (SEER) registry...
October 20, 2016: Cancer Research
Mingming Li, Shuzhi Sam Ge, Tong Heng Lee
This paper presents a novel content-driven associative memory (CDAM) to associate large-scale color images based on the subjects that represent the images' content. Compared to traditional associative memories, CDAM inherits their tolerance to random noise in images and possesses greater robustness against correlated noise that distorts an image's spatial contextual structure. A three-layer recurrent neural tensor network (RNTN) is designed as the network model of CDAM. Multiple salient objects detection algorithm and partial radial basis function (PRBF) kernel are proposed for subject determination and content-driven association, respectively...
November 29, 2016: IEEE Transactions on Cybernetics
Guang Deng
Edge-aware smoothing has been extensively studied due to its wide range of applications in computer vision and graphics.Most published works have been focused on formulating the smoothing problem in the spatial domain. In this paper, we propose a new edge-aware smoothing framework called guided wavelet shrinkage (GWS) which is formulated in the wavelet domain as a maximum a posterior estimation problem. We impose a number of desirable properties on the statistical models and the associated parameters in order to derive an effective and computationally efficient algorithm...
December 1, 2016: IEEE Transactions on Image Processing: a Publication of the IEEE Signal Processing Society
Hamed Rabiei, Frederic Richard, Olivier Coulon, Julien Lefevre
Gyrification index (GI) is an appropriate measure to quantify the complexity of the cerebral cortex. There is, however, no universal agreement on the notion of surface complexity and there are various methods in literature that evaluate different aspects of cortical folding. In this paper, we give two intuitive interpretations on folding quantification based on the magnitude and variation of the mean curvature of the cortical surface. We then present a local spectral analysis of the mean curvature to introduce two local gyrification indices that satisfy our interpretations...
November 29, 2016: IEEE Transactions on Medical Imaging
Andreas Tag, Vikrant Chauhan, Christian Huck, Bernhard Bader, Dominik Karolewski, F Maximilian Pitschi, Robert Weigel, Amelie Hagelauer
A novel approach for multiphysics modeling of bulk acoustic wave (BAW) filters is presented allowing accurate and at the same time efficient modeling of BAW filters at high power levels. The approach takes the different types of losses and their spatial distribution into account in order to provide the required input for thermal simulation. The temperature distribution determined by thermal simulation is used to modify the geometry and the layer stack of each single resonator of the filter. In this way, the required input for modeling of electromagnetic (EM) and acoustic behavior at high power level is generated...
December 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Teodora Szasz, Adrian Basarab, Denis Kouame
Beamforming (BF) in ultrasound (US) imaging has significant impact on the quality of the final image, controlling its resolution and contrast. Despite its low spatial resolution and contrast, delay-and-sum (DAS) is still extensively used nowadays in clinical applications, due to its real-time capabilities. The most common alternatives are minimum variance (MV) method and its variants, which overcome the drawbacks of DAS, at the cost of higher computational complexity that limits its utilization in real-time applications...
December 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Cristiano Ballabio, Pasquale Borrelli, Jonathan Spinoni, Katrin Meusburger, Silas Michaelides, Santiago Beguería, Andreas Klik, Sašo Petan, Miloslav Janeček, Preben Olsen, Juha Aalto, Mónika Lakatos, Anna Rymszewicz, Alexandru Dumitrescu, Melita Perčec Tadić, Nazzareno Diodato, Julia Kostalova, Svetla Rousseva, Kazimierz Banasik, Christine Alewell, Panos Panagos
Rainfall erosivity as a dynamic factor of soil loss by water erosion is modelled intra-annually for the first time at European scale. The development of Rainfall Erosivity Database at European Scale (REDES) and its 2015 update with the extension to monthly component allowed to develop monthly and seasonal R-factor maps and assess rainfall erosivity both spatially and temporally. During winter months, significant rainfall erosivity is present only in part of the Mediterranean countries. A sudden increase of erosivity occurs in major part of European Union (except Mediterranean basin, western part of Britain and Ireland) in May and the highest values are registered during summer months...
November 29, 2016: Science of the Total Environment
Yuming Guo, Hongmei Zeng, Rongshou Zheng, Shanshan Li, Gavin Pereira, Qiyong Liu, Wanqing Chen, Rachel Huxley
Although studies have examined the associations between fine particles (PM2.5) and lung cancer mortality in US and European countries, the evidence is still limited for China. In addition, no study has provided estimates of spatial variation in lung cancer mortality attributable to PM2.5 in China. In this study, we quantified the associations between lung cancer mortality and PM2.5, using a spatiotemporal model with observed data of lung cancer mortality from 75 communities from the National Cancer Registration of China from 1990 to 2009 and the annual concentrations of PM2...
November 29, 2016: Science of the Total Environment
Zewdie Aderaw Alemu, Ahmed Ali Ahmed, Alemayehu Worku Yalew, Belay Simanie Birhanu
BACKGROUND: Child undernutrition showed geographical inequalities due to variations in contextual determinants from area to area which indicates that location is an important factor in child undernutrition. However, there are limited studies on spatial epidemiology of child undernutrition in Ethiopia. This study was aimed to identify the SaTScan spatial clusters of child undernutrition in Ethiopia. METHODS: Nutritional indices of children (0-59 months) with Global Positioning System (GPS) location data were accessed from the 2011 Ethiopia Demographic and Health Survey (EDHS) after getting permission from the MEASURES Demographic and Health Survey (DHS) Program...
December 3, 2016: International Journal for Equity in Health
Joel E Cohen, Takashi Saitoh
Taylor's law (TL) asserts that the variance in a species' population density is a power-law function of its mean population density: log(variance) = a + b × log(mean). TL is widely verified. We show here that empirical time series of density of the Hokkaido gray-sided vole, Myodes rufocanus, sampled 1962-1992 at 85 locations, satisfied temporal and spatial forms of TL. The slopes (b ± standard error) of the temporal and spatial TL were estimated to be 1.613 ± 0.141 and 1.430 ± 0.132, respectively...
December 2016: Ecology
T K Chapple, T Chambert, P E Kanive, S J Jorgensen, J J Rotella, S D Anderson, A B Carlisle, B A Block
Spatial segregation of animals by class (i.e., maturity or sex) within a population due to differential rates of temporary emigration (TE) from study sites can be an important life history feature to consider in population assessment and management. However, such rates are poorly known; new quantitative approaches to address these knowledge gaps are needed. We present a novel application of multi-event models that takes advantage of two sources of detections to differentiate temporary emigration from apparent absence to quantify class segregation within a study population of double-marked (photo-identified and tagged with coded acoustic transmitters) white sharks (Carcharodon carcharias) in central California...
December 2016: Ecology
Maria Klein, Sara Teixeira, Jorge Assis, Ester A Serrão, Emanuel J Gonçalves, Rita Borges
Adults of most marine benthic and demersal fish are site-attached, with the dispersal of their larval stages ensuring connectivity among populations. In this study we aimed to infer spatial and temporal variation in population connectivity and dispersal of a marine fish species, using genetic tools and comparing these with oceanographic transport. We focused on an intertidal rocky reef fish species, the shore clingfish Lepadogaster lepadogaster, along the southwest Iberian Peninsula, in 2011 and 2012. We predicted high levels of self-recruitment and distinct populations, due to short pelagic larval duration and because all its developmental stages have previously been found near adult habitats...
2016: PloS One
Sung Il Park, Gunchul Shin, Jordan G McCall, Ream Al-Hasani, Aaron Norris, Li Xia, Daniel S Brenner, Kyung Nim Noh, Sang Yun Bang, Dionnet L Bhatti, Kyung-In Jang, Seung-Kyun Kang, Aaron D Mickle, Gregory Dussor, Theodore J Price, Robert W Gereau, Michael R Bruchas, John A Rogers
Optogenetic methods to modulate cells and signaling pathways via targeted expression and activation of light-sensitive proteins have greatly accelerated the process of mapping complex neural circuits and defining their roles in physiological and pathological contexts. Recently demonstrated technologies based on injectable, microscale inorganic light-emitting diodes (μ-ILEDs) with wireless control and power delivery strategies offer important functionality in such experiments, by eliminating the external tethers associated with traditional fiber optic approaches...
November 28, 2016: Proceedings of the National Academy of Sciences of the United States of America
Masahiro Shimizu, Yasunori Noguchi, Yukari Sakiyama, Hironori Kawakami, Tsutomu Katayama, Shoji Takada
Upon DNA replication initiation in Escherichia coli, the initiator protein DnaA forms higher-order complexes with the chromosomal origin oriC and a DNA-bending protein IHF. Although tertiary structures of DnaA and IHF have previously been elucidated, dynamic structures of oriC-DnaA-IHF complexes remain unknown. Here, combining computer simulations with biochemical assays, we obtained models at almost-atomic resolution for the central part of the oriC-DnaA-IHF complex. This complex can be divided into three subcomplexes; the left and right subcomplexes include pentameric DnaA bound in a head-to-tail manner and the middle subcomplex contains only a single DnaA...
November 29, 2016: Proceedings of the National Academy of Sciences of the United States of America
R P M J W Notermans, R J Rengelink, W Vassen
We observe a dramatic difference in optical line shapes of a ^{4}He Bose-Einstein condensate and a ^{3}He degenerate Fermi gas by measuring the 1557-nm 2 ^{3}S-2 ^{1}S magnetic dipole transition (8 Hz natural linewidth) in an optical dipole trap. The 15 kHz FWHM condensate line shape is only broadened by mean field interactions, whereas the degenerate Fermi gas line shape is broadened to 75 kHz FWHM due to the effect of Pauli exclusion on the spatial and momentum distributions. The asymmetric optical line shapes are observed in excellent agreement with line shape models for the quantum degenerate gases...
November 18, 2016: Physical Review Letters
Peter A Lind, Andrew D Farr, Paul B Rainey
Model microbial systems provide opportunity to understand the genetic bases of ecological traits, their evolution, regulation and fitness contributions. Experimental populations of Pseudomonas fluorescens rapidly diverge in spatially structured microcosms producing a range of surface-colonising forms. Despite divergent molecular routes, wrinkly spreader (WS) niche specialist types overproduce a cellulosic polymer allowing mat formation at the air-liquid interface and access to oxygen. Given the range of ways by which cells can form mats, such phenotypic parallelism is unexpected...
December 2, 2016: ISME Journal
Mehmet Can Uçar, Reinhard Lipowsky
Intracellular transport is performed by molecular motors that pull cargos along cytoskeletal filaments. Many cellular cargos are observed to move bidirectionally, with fast transport in both directions. This behaviour can be understood as a stochastic tug-of-war between two teams of antagonistic motors. The first theoretical model for such a tug-of-war, the Müller-Klumpp-Lipowsky (MKL) model, was based on two simplifying assumptions: (i) both motor teams move with the same velocity in the direction of the stronger team, and (ii) this velocity matching and the associated force balance arise immediately after the rebinding of an unbound motor to the filament...
December 2, 2016: Soft Matter
Kai Luo, Runkui Li, Wenjing Li, Zongshuang Wang, Xinming Ma, Ruiming Zhang, Xin Fang, Zhenglai Wu, Yang Cao, Qun Xu
The exploration of spatial variation and predictors of the effects of nitrogen dioxide (NO2) on fatal health outcomes is still sparse. In a multilevel case-crossover study in Beijing, China, we used mixed Cox proportional hazard model to examine the citywide effects and conditional logistic regression to evaluate the district-specific effects of NO2 on cardiovascular mortality. District-specific predictors that could be related to the spatial pattern of NO2 effects were examined by robust regression models...
December 2, 2016: Scientific Reports
Paul Villoutreix, Julien Delile, Barbara Rizzi, Louise Duloquin, Thierry Savy, Paul Bourgine, René Doursat, Nadine Peyriéras
We conducted a quantitative comparison of developing sea urchin embryos based on the analysis of five digital specimens obtained by automatic processing of in toto 3D+ time image data. These measurements served the reconstruction of a prototypical cell lineage tree able to predict the spatiotemporal cellular organisation of a normal sea urchin blastula. The reconstruction was achieved by designing and tuning a multi-level probabilistic model that reproduced embryo-level dynamics from a small number of statistical parameters characterising cell proliferation, cell surface area and cell volume evolution along the cell lineage...
December 2, 2016: Scientific Reports
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