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Spatial analysis

Erez James Cohen, Riccardo Bravi, Diego Minciacchi
The three dimensional (3D) reconstruction of movement from videos is widely utilized as a method for spatial analysis of movement. Several approaches exist for a 3D reconstruction of movement using 2D video projection, most of them require the use of at least two cameras as well as the application of relatively complex algorithms. While a few approaches also exist for 3D reconstruction of movement with a single camera, they are not widely implemented due to tedious and complicated methods of calibration. Here we propose a simple method that allows for a 3D reconstruction of movement by using a single projection and three calibration markers...
2017: PloS One
Mark Chiew, Wenwen Jiang, Brian Burns, Peder Larson, Adam Steel, Peter Jezzard, M Albert Thomas, Uzay E Emir
It has been shown that density-weighted (DW) k-space sampling with spiral and conventional phase encoding trajectories reduces spatial side lobes in magnetic resonance spectroscopic imaging (MRSI). In this study, we propose a new concentric ring trajectory (CRT) for DW-MRSI that samples k-space with a density that is proportional to a spatial, isotropic Hanning window. The properties of two different DW-CRTs were compared against a radially equidistant (RE) CRT and an echo-planar spectroscopic imaging (EPSI) trajectory in simulations, phantoms and in vivo experiments...
October 18, 2017: NMR in Biomedicine
Qixin He, Joyce R Prado, L Lacey Knowles
Climatic or environmental change is not only driving distributional shifts in species today, but it has also caused distributions to expand and contract in the past. Inferences about the geographic locations of past populations, especially regions that served as refugia (i.e., source populations) and migratory routes are a challenging endeavor. Refugial areas may be evidenced from fossil records or regions of temporal stability inferred from ecological niche models. Genomic data offer an alternative and broadly applicable source of information about the locality of refugial areas, especially relative to fossil data, which are either unavailable or incomplete for most species...
October 16, 2017: Molecular Ecology
Brenda N Nakagaki, Maria A Freitas-Lopes, Érika Carvalho, Raquel Carvalho-Gontijo, Hortência M Castro-Oliveira, Rafael M Rezende, Denise C Cara, Mônica M Santos, Rodrigo Pestana Lopes, Bruna A David, Gustavo B Menezes
Resident and circulating immune cells have been extensively studied due to their almost ubiquitous role in cell biology. Despite their classification under the "immune cell department", it is becoming increasingly clear that these cells are involved in many different non-immune related phenomena, including fetus development, vascular formation, memory, social behavior and many other phenotypes. There is a huge potential in combining high-throughput assays - including flow cytometry and gene analysis - with in vivo imaging...
October 16, 2017: Anais da Academia Brasileira de Ciências
Daud H Khan, Steven A Roberts, John Robert Cressman, Nitin Agrawal
Hypoxic regions exist within most solid tumors and often lead to altered cellular metabolism, metastasis, and drug resistance. Reliable generation and detection of biomimetic gaseous gradients in vitro is challenging due to low spatiotemporal resolution and poor longevity of gradients utilizing microfluidic techniques. Here, we present a novel and simplistic approach for producing gradients of dissolved oxygen (DO) within a lab-on-a-chip platform. Linear and stable DO gradients with high spatial resolution are established by introducing pre-gassed media into the gradient generating network...
October 18, 2017: Scientific Reports
Raissa Marques Mendonca, Jennifer M Daley, Michelle L Hudson, Christian Schlekat, G Allen Burton, David Costello
In aquatic ecosystems, the cycling and toxicity of nickel (Ni) are coupled to other elemental cycles that can limit its bioavailability. Current sediment risk assessment approaches consider acid-volatile sulfide (AVS) as the major binding phase for Ni, but have not yet incorporated ligands that are present in oxic sediments. Our study aimed to assess how metal oxides play a role in Ni bioavailability in surficial sediments exposed to effluent from two mine sites. We coupled spatially explicit sediment geochemistry (i...
October 18, 2017: Environmental Science & Technology
Charles Reilly, Donald E Ingber
Many have recognized the potential value of facilitating activities that span the art-science interface for the benefit of society; however, there are few examples that demonstrate how pursuit of an artistic agenda can lead to scientific insights. Here, we describe how we set out to produce an entertaining short film depicting the fertilization of the egg by sperm as a parody of a preview for another Star Wars movie to excite the public about science, but ended up developing a simulation tool for multiscale modeling...
October 18, 2017: ACS Nano
José Luis Marrugo-Negrete, Javier Alonso Ruiz-Guzmán, Ana Carolina Ruiz-Fernández
Total mercury concentrations (T-Hg) and stable isotope ratios (δ(15)N and δ(13)C) were analyzed in the muscle of fish, collected at two marshes impacted by gold mining in Northern Colombia, to evaluate the seasonal and spatial behavior of these variables and mercury biomagnification based on their relationship with δ(15)N ratios in the fish. There was not significant (p > 0.05) seasonal differences (dry and rainy season) in δ(15)N and δ(13)C values in none marsh, suggesting that these fish species keep a similar feed pattern within each marsh along the year...
October 17, 2017: Archives of Environmental Contamination and Toxicology
Ladd Irvine, Daniel M Palacios, Jorge Urbán, Bruce Mate
Here, we describe the diving behavior of sperm whales (Physeter macrocephalus) using the Advanced Dive Behavior (ADB) tag, which records depth data at 1-Hz resolution and GPS-quality locations for over 1 month, before releasing from the whale for recovery. A total of 27 ADB tags were deployed on sperm whales in the central Gulf of California, Mexico, during spring 2007 and 2008, of which 10 were recovered for data download. Tracking durations of all tags ranged from 0 to 34.5 days (median = 2.3 days), and 0...
October 2017: Ecology and Evolution
Er-Fu Dai, Xiao-Li Wang, Jian-Jia Zhu, Wei-Min Xi
There is increasing interest worldwide regarding managing plantation forests in a manner that maintains or improves timber production, enhances ecosystem services, and promotes long-term sustainability of forest resources. We selected the Gan River Basin, the largest catchment of Poyang Lake and a region with a typical plantation distribution in South China, as the study region. We evaluated and mapped four important forest ecosystem services, including wood volume, carbon storage, water yield, and soil retention at a 30 × 30 m resolution, then quantified their trade-offs and synergies at the county and subwatershed scales...
October 2017: Ecology and Evolution
Benjamin S Ramage, Daniel J Johnson, Erika Gonzalez-Akre, William J McShea, Kristina J Anderson-Teixeira, Norman A Bourg, Keith Clay
Local tree species diversity is maintained in part by conspecific negative density dependence (CNDD). This pervasive mechanism occurs in a variety of forms and ecosystems, but research to date has been heavily skewed toward tree seedling survival in tropical forests. To evaluate CNDD more broadly, we investigated how sapling growth rates were affected by conspecific adult neighbors in a fully mapped 25.6 ha temperate deciduous forest. We examined growth rates as a function of the local adult tree neighborhood (via spatial autoregressive modeling) and compared the spatial positioning of faster-growing and slower-growing saplings with respect to adult conspecific and heterospecific trees (via bivariate point pattern analysis)...
October 2017: Ecology and Evolution
Yunzhi Ling, Xiaohong Li, Li Yu, Qisheng Liang, Xuewu Lin, Xiaodi Yang, Hongtao Wang, Ye Zhang
The association of anesthetic exposure in infants or young children with the long-term impairment of neurologic functions has been reported previously; however, the underlying mechanisms remain largely unknown. In order to identify dysregulated gene expression underlying long-term cognitive impairment caused by sevoflurane exposure at the postnatal stage, the present study initially performed behavioral tests on adult Wistar rats, which received 3% sevoflurane at postnatal day 7 (P7) for different time course...
October 2017: Experimental and Therapeutic Medicine
Timm Schoening, Daniel O B Jones, Jens Greinert
Poly-metallic nodules are a marine resource considered for deep sea mining. Assessing nodule abundance is of interest for mining companies and to monitor potential environmental impact. Optical seafloor imaging allows quantifying poly-metallic nodule abundance at spatial scales from centimetres to square kilometres. Towed cameras and diving robots acquire high-resolution imagery that allow detecting individual nodules and measure their sizes. Spatial abundance statistics can be computed from these size measurements, providing e...
October 17, 2017: Scientific Reports
Thien Nguyen, Charles D Hill, Lloyd C L Hollenberg, Matthew R James
Solid-state spin-based qubits offer good prospects for scaling based on their long coherence times and nexus to large-scale electronic scale-up technologies. However, high-threshold quantum error correction requires a two-dimensional qubit array operating in parallel, posing significant challenges in fabrication and control. While architectures incorporating distributed quantum control meet this challenge head-on, most designs rely on individual control and readout of all qubits with high gate densities. We analysed the fan-out routing overhead of a dedicated control line architecture, basing the analysis on a generalised solid-state spin qubit platform parameterised to encompass Coulomb confined (e...
October 17, 2017: Scientific Reports
Jinjuan Gao, Huahong Shi, Zhijun Dai, Xuefei Mei, Haibo Zong, Hongwei Yang, Lingling Hu, Shushi Li
Anthropogenic activities are driving an increase in sediment contamination in coastal areas. This poses significant challenges for the management of estuarine ecosystems and their adjacent seas worldwide. However, few studies have been conducted on how dynamic mechanisms affect the sediment toxicity in the estuarine environment. This study was designed to investigate the linkages between sediment toxicity and hydrodynamics in the Yangtze River Estuary (YRE) area. High sediment toxicity was found in the Yangtze River mouth (Region I), the depocenter of the Yangtze River Delta (Region II), and the southeastern area of the adjacent sea (Region III), while low sediment toxicity was found in the northeastern offshore region (Region IV)...
October 14, 2017: Environmental Pollution
Arcangeli Antonella, Campana Ilaria, Angeletti Dario, Atzori Fabrizio, Azzolin Marta, Carosso Lara, Di Miccoli Valentina, Giacoletti Antonio, Gregorietti Martina, Luperini Cristina, Paraboschi Miriam, Pellegrino Giuliana, Ramazio Martina, Sarà Gianluca, Crosti Roberto
Marine litter is a major source of pollution in the Mediterranean basin, but despite legislative requirements, scant information is available for the ongoing assessment of this threat. Using higher size classes as proxy for litter distribution, this study gave a synoptic estimation of the amount, composition, and distribution of floating macro-litter in the Mediterranean. The average amount of macro-litter was in a range of 2-5items/km(2), with the highest in the Adriatic basin. Seasonal patterns were present in almost all study areas and were significant in the Ligurian Sea, Sardinian-Balearic basin, and Central Tyrrhenian Sea...
October 14, 2017: Marine Pollution Bulletin
Rémy Claveau, Paul Montgomery, Manuel Flury, Denis Montaner
Full-field optical coherence tomography (FF-OCT) is a widely used technique for applications such as biological imaging, optical metrology, and materials characterization, providing structural and spectral information. By spectral analysis of the backscattered light, the technique of spectroscopic-OCT enables the differentiation of structures having different spectral properties, but not the determination of their reflectance spectrum. For surface measurements, this can be achieved by applying a Fourier transform to the interferometric signals and using an accurate calibration of the optical system...
August 21, 2017: Optics Express
Eileen Otte, Kemal Tekce, Cornelia Denz
Vector beams are of major importance to tailor tightly focused fields by creating an additional z-polarization component. Till now, mainly focusing properties of fundamental vector beams have been investigated, whereas the knowledge of focused higher-order singular vector fields is still missing. We fill this gap by numerical analysis of these fields, applying their attractive characteristics as including a spatially adjustable amount of radial and azimuthal components. We demonstrate the realization of three-dimensional polarization structures whose total intensity resembles dark stars and bright flowers...
August 21, 2017: Optics Express
Yunli Dang, Zhiyong Zhao, Ming Tang, Can Zhao, Lin Gan, Songnian Fu, Tongqing Liu, Weijun Tong, Perry Ping Shum, Deming Liu
Featuring a dependence of Brillouin frequency shift (BFS) on temperature and strain changes over a wide range, Brillouin distributed optical fiber sensors are however essentially subjected to the relatively poor temperature/strain measurement resolution. On the other hand, phase-sensitive optical time-domain reflectometry (Φ-OTDR) offers ultrahigh temperature/strain measurement resolution, but the available frequency scanning range is normally narrow thereby severely restricts its measurement dynamic range...
August 21, 2017: Optics Express
Gangi Reddy Salla, Vijay Kumar, Yoko Miyamoto, R P Singh
Polarization speckle is a fine granular light pattern having spatially varying random polarization profile. We generate these speckle patterns by using the scattering of Poincaré beams, a special class of vector vortex beams, through a ground glass plate. Here, the Poincaré beams are generated using a polarization sensitive spatial light modulator displaying an on-axis hologram corresponding to an optical vortex phase profile. The different inhomogeneities of the rough surface experience different polarizations, which control the ability for scattered waves to interfere at the detection plane and causes a spatially varying polarization profile...
August 21, 2017: Optics Express
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