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Spatial patterning

Cheng Jin, Jianjiang Feng, Lei Wang, Heng Yu, Jiang Liu, Jiwen Lu, Jie Zhou
In this paper, we present an approach for left atrial appendage (LAA) multi-phase fast segmentation and quantitative assisted diagnosis of atrial fibrillation (AF) based on 4D-CT data. We take full advantage of the temporal dimension information to segment the living, flailed LAA based on a parametric max-flow method and graph-cut approach to build 3-D model of each phase. To assist the diagnosis of AF, we calculate the volumes of 3-D models, and then generate a "volume-phase" curve to calculate the important dynamic metrics: ejection fraction, filling flux, and emptying flux of the LAA's blood by volume...
March 9, 2018: Computers in Biology and Medicine
James R Smith, Jaboury Ghazoul, David F R P Burslem, Akira Itoh, Eyen Khoo, Soon Leong Lee, Colin R Maycock, Satoshi Nanami, Kevin Kit Siong Ng, Chris J Kettle
Documenting the scale and intensity of fine-scale spatial genetic structure (FSGS), and the processes that shape it, is relevant to the sustainable management of genetic resources in timber tree species, particularly where logging or fragmentation might disrupt gene flow. In this study we assessed patterns of FSGS in three species of Dipterocarpaceae (Parashorea tomentella, Shorea leprosula and Shorea parvifolia) across four different tropical rain forests in Malaysia using nuclear microsatellite markers. Topographic heterogeneity varied across the sites...
2018: PloS One
Michele Furlan, Laura Babcock, Antonino Vallesi
Traditionally, the left hemisphere has been thought to extract mainly verbal patterns of information, but recent evidence has shown that the left Inferior Frontal Gyrus (IFG) is active during inductive reasoning in both the verbal and spatial domains. We aimed to understand whether the left IFG supports inductive reasoning in a domain-specific or domain-general fashion. To do this we used Multi-Voxel Pattern Analysis to decode the representation of domain during a rule search task. Thirteen participants were asked to extract the rule underlying streams of letters presented in different spatial locations...
2018: PloS One
Thomas Lilienkamp, Ulrich Parlitz
Transient chaos in spatially extended systems can be characterized by the length of the transient phase, which typically grows quickly with the system size (supertransients). For a large class of these systems, the chaotic phase terminates abruptly, without any obvious precursors in commonly used observables. Here we investigate transient spatiotemporal chaos in two different models of this class. By probing the state space using perturbed trajectories we show the existence of a "terminal transient phase," which occurs prior to the abrupt collapse of chaotic dynamics...
March 2, 2018: Physical Review Letters
Jyoti Singh Kirar, R K Agrawal
This paper presents a novel algorithm (CVSTSCSP) for determining discriminative features from an optimal combination of temporal, spectral and spatial information for motor imagery brain computer interfaces. The proposed method involves four phases. In the first phase, EEG signal is segmented into overlapping time segments and bandpass filtered through frequency filter bank of variable size subbands. In the next phase, features are extracted from the segmented and filtered data using stationary common spatial pattern technique (SCSP) that can handle the non- stationarity and artifacts of EEG signal...
March 16, 2018: Journal of Medical Systems
Qian Zhang, Shengli Wang, Zhongren Nan, Yepu Li, Fei Zang
Wastewater irrigation can increase metal concentrations in soil and wheat, thereby posing metal-associated health risk via food ingestion. We investigated levels of mercury (Hg) and arsenic (As) in roots, husks, stems, leaves, and grains of wheat and their fractionations in farmland soil from Baiyin City, an industrial and mining city, northwest China. Results show that the mean concentrations of Hg in soils from Dongdagou and Xidagou stream in Baiyin were 8.5 times and three times higher than local soil background values, respectively...
March 15, 2018: Environmental Science and Pollution Research International
Michael J R Martin, Stephen A Matthews, Barrett A Lee
Although increasing racial and ethnic diversity is a demographic trend with society-wide implications, it has advanced farther in some parts of the United States than others. Our research seeks to understand this unevenness at the local level. Drawing on 1980-2010 census data, we use an innovative spatial analytic approach to examine the spread or diffusion of diversity across counties in the 48 contiguous states. Three perspectives-locational persistence, spatial assimilation, and institutional hub-offer different expectations about the nature of the diffusion process...
October 2017: Spatial Demography
Jacobus H Visser, Nigel C Bennett, Bettine Jansen van Vuuren
The subterranean niche harbours animals with extreme adaptations. These adaptations decrease the vagility of taxa and, along with other behavioural adaptations, often result in isolated populations characterized by small effective population sizes, high inbreeding, population bottlenecks, genetic drift and consequently, high spatial genetic structure. Although information is available for some species, estimates of genetic diversity and whether this variation is spatially structured, is lacking for the Cape mole-rat (Georychus capensis)...
2018: PloS One
Xiangyu Chang, Jingzhou Shen, Xiaoling Lu, Shuai Huang
The emerging Bicycle Sharing System (BSS) provides a new social microscope that allows us to "photograph" the main aspects of the society and to create a comprehensive picture of human mobility behavior in this new medium. BSS has been deployed in many major cities around the world as a short-distance trip supplement for public transportations and private vehicles. A unique value of the bike flow data generated by these BSSs is to understand the human mobility in a short-distance trip. This understanding of the population on short-distance trip is lacking, limiting our capacity in management and operation of BSSs...
2018: PloS One
Plansky Hoang, Jason Wang, Bruce R Conklin, Kevin E Healy, Zhen Ma
The creation of human induced pluripotent stem cells (hiPSCs) has provided an unprecedented opportunity to study tissue morphogenesis and organ development through 'organogenesis-in-a-dish'. Current approaches to cardiac organoid engineering rely on either direct cardiac differentiation from embryoid bodies (EBs) or generation of aligned cardiac tissues from predifferentiated cardiomyocytes from monolayer hiPSCs. To experimentally model early cardiac organogenesis in vitro, our protocol combines biomaterials-based cell patterning with stem cell organoid engineering...
April 2018: Nature Protocols
Amy E Leedale, Stuart P Sharp, Michelle Simeoni, Elva J H Robinson, Ben J Hatchwell
In animal societies, characteristic demographic and dispersal patterns may lead to genetic structuring of populations, generating the potential for kin selection to operate. However, even in genetically structured populations, social interactions may still require kin discrimination for cooperative behaviour to be directed towards relatives. Here, we use molecular genetics and long-term field data to investigate genetic structure in an adult population of long-tailed tits Aegithalos caudatus, a cooperative breeder in which helping occurs within extended kin networks, and relate this to patterns of helping with respect to kinship...
March 15, 2018: Molecular Ecology
Amado M Velázquez-Benítez, K Yanín Guerra-Santillán, Raúl Caudillo-Viurquez, J Enrique Antonio-López, Rodrigo Amezcua-Correa, Juan Hernández-Cordero
We demonstrate a simple approach based on a photonic lantern spatial-mode multiplexer and a few-mode fiber for optical and manipulation of multiple microspheres. Selective generation of linearly polarized (LP) fiber modes provides light patterns useful for trapping one or multiple microparticles. Furthermore, rotation of the particles can be achieved by switching between degenerate LP modes, as well as through polarization rotation of the input light. Our results show that emerging fiber optic devices such as photonic lanterns can provide a versatile and compact means for developing optical fiber traps...
March 15, 2018: Optics Letters
Ayush Bhargava, Jeffrey W Bertrand, Anand K Gramopadhye, Kapil C Madathil, Sabarish V Babu
With costs of head-mounted displays (HMDs) and tracking technology decreasing rapidly, various virtual reality applications are being widely adopted for education and training. Hardware advancements have enabled replication of real-world interactions in virtual environments to a large extent, paving the way for commercial grade applications that provide a safe and risk-free training environment at a fraction of the cost. But this also mandates the need to develop more intrinsic interaction techniques and to empirically evaluate them in a more comprehensive manner...
April 2018: IEEE Transactions on Visualization and Computer Graphics
N Fayard, A Goetschy, R Pierrat, R Carminati
We study theoretically the mutual information between reflected and transmitted speckle patterns produced by wave scattering from disordered media. The mutual information between the two speckle images recorded on an array of N detection points (pixels) takes the form of long-range intensity correlation loops that we evaluate explicitly as a function of the disorder strength and the Thouless number g. Our analysis, supported by extensive numerical simulations, reveals a competing effect of cross-sample and surface spatial correlations...
February 16, 2018: Physical Review Letters
Joshua L Haworth, Adam J Strang, Mathias Hieronymus, Mark S Walsh
BACKGROUND AND AIM: Many people use balance training as a rehabilitation or habilitation modality. Although the time course of changes to temporal and spatial aspects of postural sway over the initial weeks of such training is as yet unclear. Particularly, we sought to explore the effects of training on sway during a dynamic task of stance on an ultra-compliant surface. Such a task provides different mechanical, and thus sensorimotor, constraints compared to stance on a solid surface...
March 15, 2018: Somatosensory & Motor Research
Kathleen S Rockland
Recent commentaries on the role of the thalamus consider a wide sphere of influence beyond sensory-motor transformation, to include task-relevant cognitive processes. In this short review, I reconsider known anatomic features of corticothalamic connectivity, primarily for macaque monkey, and discuss these as part of an intricate network architecture consistent with multiple connectional re-combinations and a diversity of functional tasks. Drawing mainly on results from single axon analysis for the two broad classes of corticothalamic (CT) connections, I review the strikingly complementary spatial parameters of their extrinsic CT arbors in relation to intrinsic cortical collaterals...
March 14, 2018: European Journal of Neuroscience
Adrian V Horodnic, Sorin Mazilu, Liviu Oprea
In order to explain informal payments in public health care services in Romania, this paper evaluates the relationship between extra payments or valuable gifts (apart from official fees) and the level of tolerance to corruption, as well as the socio-economic and spatial patterns across those individuals offering informal payments. To evaluate this, a survey undertaken in 2013 is reported. Using logistic regression analysis, the findings are that patients with a high tolerance to corruption, high socio-economic risk (those divorced, separated, or with other form of marital status, and those not working), and located in rural or less affluent areas are more likely to offer (apart from official fees) extra payments or valuable gifts for health care services...
March 15, 2018: International Journal of Health Planning and Management
S Kaiser, S V Radl, J Manhart, S Ayalur-Karunakaran, T Griesser, A Moser, C Ganser, C Teichert, W Kern, S Schlögl
The present work aims at the preparation of dry adhesives with switchable bonding properties by using the reversible nature of the [4πs+4πs] cycloaddition of anthracenes. Photo-responsive hydrogenated carboxylated nitrile butadiene rubber with photo-responsive pendant anthracene groups is prepared by one-pot synthesis. The formation of 3D networks relies on the photodimerization of the anthracene moieties upon UV exposure (λ > 300 nm). Controlled cleavage of the crosslink sites is achieved by either deep UV exposure (λ = 254 nm) or thermal dissociation at 70 °C...
March 15, 2018: Soft Matter
Valentine L Marcar, Silvana Baselgia, Barbara Lüthi-Eisenegger, Lutz Jäncke
Introduction: Retinal input processing in the human visual system involves a phasic and tonic neural response. We investigated the role of the magno- and parvocellular systems by comparing the influence of the active neural population size and its discharge activity on the amplitude and latency of four VEP components. Method: We recorded the scalp electric potential of 20 human volunteers viewing a series of dartboard images presented as a pattern reversing and pattern on-/offset stimulus...
March 2018: Brain and Behavior
Christian Herrmann, Penelope Vounatsou, Beat Thürlimann, Nicole Probst-Hensch, Christian Rothermundt, Silvia Ess
INTRODUCTION: In the past decades, mortality due to breast cancer has declined considerably in Switzerland and other developed countries. The reasons for this decline remain controversial as several factors occurred almost simultaneously, including important advances in treatment approaches, breast cancer awareness and the introduction of mammography screening programmes in many European countries. In Switzerland, mammography screening programmes (MSPs) have existed in some regions for over 20 years but do not yet exist in others...
March 14, 2018: BMJ Open
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