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Spatio-temporal modeling

Aurel A Lazar, Nikul H Ukani, Yiyin Zhou
We investigate the sparse functional identification of complex cells and the decoding of spatio-temporal visual stimuli encoded by an ensemble of complex cells. The reconstruction algorithm is formulated as a rank minimization problem that significantly reduces the number of sampling measurements (spikes) required for decoding. We also establish the duality between sparse decoding and functional identification and provide algorithms for identification of low-rank dendritic stimulus processors. The duality enables us to efficiently evaluate our functional identification algorithms by reconstructing novel stimuli in the input space...
January 18, 2018: Journal of Mathematical Neuroscience
Nyaguara O Amek, Annemieke Van Eijk, Kim A Lindblade, Mary Hamel, Nabie Bayoh, John Gimnig, Kayla F Laserson, Laurence Slutsker, Thomas Smith, Penelope Vounatsou
BACKGROUND: Malaria transmission reduction is a goal of many malaria control programmes. Little is known of how much mortality can be reduced by specific reductions in transmission. Verbal autopsy (VA) is widely used for estimating malaria specific mortality rates, but does not reliably distinguish malaria from other febrile illnesses. Overall malaria attributable mortality includes both direct and indirect deaths. It is unclear what proportion of the deaths averted by reducing malaria transmission are classified as malaria in VA...
January 18, 2018: Malaria Journal
Yi Tian, Yu Kong, Qiuqi Ruan, Gaoyun An, Yun Fu
In this paper, we present a novel two-layer video representation for human action recognition employing hierarchical group sparse encoding technique and spatio-temporal structure. In the first layer, a new sparse encoding method named locally consistent group sparse coding (LCGSC) is proposed to make full use of motion and appearance information of local features. LCGSC method not only encodes global layouts of features within the same video-level groups, but also captures local correlations between them, which obtains expressive sparse representations of video sequences...
April 2018: IEEE Transactions on Image Processing: a Publication of the IEEE Signal Processing Society
Arja Ray, Rachel K Morford, Nima Ghaderi, David J Odde, Paolo P Provenzano
Carcinoma cells frequently expand and invade from a confined lesion, or multicellular clusters, into and through the stroma on the path to metastasis, often with an efficiency dictated by the architecture and composition of the microenvironment. Specifically, in desmoplastic carcinomas such as those of the breast, aligned collagen tracks provide contact guidance cues for directed cancer cell invasion. Yet, the evolving dynamics of this process of invasion remains poorly understood, in part due to difficulties in continuously capturing both spatial and temporal heterogeneity and progression to invasion in experimental systems...
January 17, 2018: Integrative Biology: Quantitative Biosciences From Nano to Macro
Foon Yin Lai, Coral Gartner, Wayne Hall, Steve Carter, Jake O'Brien, Benjamin J Tscharke, Frederic Been, Cobus Gerber, Jason White, Phong Thai, Raimondo Bruno, Jeremy Prichard, K Paul Kirkbride, Jochen F Mueller
BACKGROUND AND AIMS: Tobacco and alcohol consumption remain priority public health issues worldwide. As participation in population-based surveys has fallen, it is increasingly challenging to estimate accurately the prevalence of alcohol and tobacco use. Wastewater-based epidemiology (WBE) is an alternative approach for estimating substance use at the population level that does not rely on survey participation. This study examined spatio-temporal patterns in nicotine (a proxy for tobacco) and alcohol consumption in the Australian population via WBE...
January 14, 2018: Addiction
Mark A Lewis, Nathan G Marculis, Zhongwei Shen
To understand the effects that the climate change has on the evolution of species as well as the genetic consequences, we analyze an integrodifference equation (IDE) models for a reproducing and dispersing population in a spatio-temporal heterogeneous environment described by a shifting climate envelope. Our analysis on the IDE focuses on the persistence criterion, travelling wave solutions, and the inside dynamics. First, the persistence criterion, characterizing the global dynamics of the IDE, is established in terms of the basic reproduction number...
January 13, 2018: Journal of Mathematical Biology
Yoshitaka Imaizumi, Noriyuki Suzuki, Fujio Shiraishi, Daisuke Nakajima, Shigeko Serizawa, Takeo Sakurai, Hiroaki Shiraishi
In pesticide risk management in Japan, predicted environmental concentrations are estimated by a tiered approach, and the Ministry of the Environment also performs field surveys to confirm the maximum concentrations of pesticides with risk concerns. To contribute to more efficient and effective field surveys, we developed the Pesticide Chemicals High Resolution Estimation Method (PeCHREM) for estimating spatially and temporally variable emissions of various paddy herbicides from paddy fields to the environment...
January 12, 2018: Environmental Science. Processes & Impacts
Markus M Knodel, Arne Nägel, Sebastian Reiter, Andreas Vogel, Paul Targett-Adams, John McLauchlan, Eva Herrmann, Gabriel Wittum
Exploring biophysical properties of virus-encoded components and their requirement for virus replication is an exciting new area of interdisciplinary virological research. To date, spatial resolution has only rarely been analyzed in computational/biophysical descriptions of virus replication dynamics. However, it is widely acknowledged that intracellular spatial dependence is a crucial component of virus life cycles. The hepatitis C virus-encoded NS5A protein is an endoplasmatic reticulum (ER)-anchored viral protein and an essential component of the virus replication machinery...
January 8, 2018: Viruses
Laurent Bonnasse-Gahot, Henri Berestycki, Marie-Aude Depuiset, Mirta B Gordon, Sebastian Roché, Nancy Rodriguez, Jean-Pierre Nadal
As a large-scale instance of dramatic collective behaviour, the 2005 French riots started in a poor suburb of Paris, then spread in all of France, lasting about three weeks. Remarkably, although there were no displacements of rioters, the riot activity did travel. Access to daily national police data has allowed us to explore the dynamics of riot propagation. Here we show that an epidemic-like model, with just a few parameters and a single sociological variable characterizing neighbourhood deprivation, accounts quantitatively for the full spatio-temporal dynamics of the riots...
January 8, 2018: Scientific Reports
Menghan Hu, Guangtao Zhai, Duo Li, Yezhao Fan, Huiyu Duan, Wenhan Zhu, Xiaokang Yang
To achieve the simultaneous and unobtrusive breathing rate (BR) and heart rate (HR) measurements during nighttime, we leverage a far-infrared imager and an infrared camera equipped with IR-Cut lens and an infrared lighting array to develop a dual-camera imaging system. A custom-built cascade face classifier, containing the conventional Adaboost model and fully convolutional network trained by 32K images, was used to detect the face region in registered infrared images. The region of interest (ROI) inclusive of mouth and nose regions was afterwards confirmed by the discriminative regression and coordinate conversions of three selected landmarks...
2018: PloS One
Zirong Ye, Li Xu, Zi Zhou, Yafei Wu, Ya Fang
Most previous research on the disparities of hypertension risk has neither simultaneously explored the spatio-temporal disparities nor considered the spatial information contained in the samples, thus the estimated results may be unreliable. Our study was based on the China Health and Nutrition Survey (CHNS), including residents over 12 years old in seven provinces from 1991 to 2011. Bayesian B-spline was used in the extended shared component model (SCM) for fitting temporal-related variation to explore spatio-temporal distribution in the odds ratio (OR) of hypertension, reveal gender variation, and explore latent risk factors...
January 2, 2018: International Journal of Environmental Research and Public Health
M E Jácome-Flores, Miguel Delibes, Thorsten Wiegand, José M Fedriani
Background and Aims: Nursery pollination is a highly specialized interaction in which pollinators breed inside plant reproductive structures. Pollinator occupancy of host plants often depends on plant location, flowering synchrony and sex. The nursery pollination system between the dioecious dwarf palm Chamaerops humilis (Arecaceae) and the host-specific palm flower weevil Derelomus chamaeropsis was investigated. For the first time, sex, flowering synchrony and spatial distribution of plants was related to the occupancy probability and the abundance of D...
January 2, 2018: Annals of Botany
Ying Wang, Yu-Hong Lin, Yan Wu, Zong-Feng Yao, Jie Tang, Lin Shen, Rui Wang, Shu-Qin Ding, Jian-Guo Hu, He-Zuo Lü
Interferon-induced transmembrane protein 1 (IFITM1) is a member of the IFITM family that is associated with some acute-phase cytokine-stimulated response. Recently, we demonstrated that IFITM1 was significantly upregulated in the injured spinal cords at the mRNA level. However, its expression and cellular localization at the protein level is still unclear. Here, a rat model of spinal cord injury (SCI) was performed to investigate the spatio-temporal expression of IFITM1 after SCI. IFITM1 mRNA and protein were assessed by quantitative reverse transcription-PCR and western blot, respectively...
January 1, 2018: Journal of Histochemistry and Cytochemistry: Official Journal of the Histochemistry Society
Yoav Shechtman, Anna-Karin Gustavsson, Petar N Petrov, Elisa Dultz, Maurice Y Lee, Karsten Weis, W E Moerner
We report the observation of chromatin dynamics in living budding yeast (Saccharomyces cerevisiae) cells, in three-dimensions (3D). Using dual color localization microscopy and employing a Tetrapod point spread function, we analyze the spatio-temporal dynamics of two fluorescently labeled DNA loci surrounding the GAL locus. From the measured trajectories, we obtain different dynamical characteristics in terms of inter-loci distance and temporal variance; when the GAL locus is activated, the 3D inter-loci distance and temporal variance increase compared to the inactive state...
December 1, 2017: Biomedical Optics Express
Suleman Atique, Ta-Chien Chan, Chien-Chou Chen, Chien-Yeh Hsu, Somia Iqtidar, Valérie R Louis, Syed Abdul Shabbir, Ting-Wu Chuang
INTRODUCTION: Dengue has been endemic to Pakistan in the last two decades. There was a massive outbreak in the Swat valley in 2013. Here we demonstrate the spatio-temporal clustering and diffusion patterns of the dengue outbreak. METHODS: Dengue case data were acquired from the hospital records in the Swat district of Pakistan. Ring maps visualize the distribution and diffusion of the number of cases and incidence of dengue at the level of the union council. We applied space-time scan statistics to identify spatio-temporal clusters...
December 26, 2017: Journal of Infection and Public Health
Bismay Ranjan Tripathy, Haroon Sajjad, Christopher D Elvidge, Yu Ting, Prem Chandra Pandey, Meenu Rani, Pavan Kumar
Changes in the pattern of electric power consumption in India have influenced energy utilization processes and socio-economic development to greater extent during the last few decades. Assessment of spatial distribution of electricity consumption is, thus, essential for projecting availability of energy resource and planning its infrastructure. This paper makes an attempt to model the future electricity demand for sustainable energy and its management in India. The nighttime light database provides a good approximation of availability of energy...
December 27, 2017: Environmental Management
Daniel Wiese, Jeronimo Rodriguez Escobar, Yohsiang Hsu, Rob J Kulathinal, Allison Hayes-Conroy
Public and scientific conceptions of identity are changing alongside advances in biotechnology, with important relevance to health and medicine. In particular, biological identity, once predominantly conceived as static (e.g., related to DNA, dental records, fingerprints) is now being recognized as dynamic or fluid, mirroring contemporary understandings of psychological and social identity. The dynamism of biological identity comes from the individual body's unique relationship with the world surrounding it, and therefore may best be described as biosocial...
December 18, 2017: Social Science & Medicine
Kelly J Brunst, Marco Sanchez-Guerra, Yueh-Hsiu Mathilda Chiu, Ander Wilson, Brent A Coull, Itai Kloog, Joel Schwartz, Kasey J Brennan, Michelle Bosquet Enlow, Robert O Wright, Andrea A Baccarelli, Rosalind J Wright
BACKGROUND: Prenatal ambient fine particulate matter (PM2.5) and maternal chronic psychosocial stress have independently been linked to changes in mithochondrial DNA copy number (mtDNAcn), a marker of mitochondrial response and dysfunction. Further, overlapping research shows sex-specific effects of PM2.5 and stress on developmental outcomes. Interactions among PM2.5, maternal stress, and child sex have not been examined in this context. METHODS: We examined associations among exposure to prenatal PM2...
December 14, 2017: Environment International
Yan Feng, Shiwei Liao, Changjuan Wei, Dongmei Jia, Kristofer Wood, Qiang Liu, Xiaoying Wang, Fu-Dong Shi, Wei-Na Jin
BACKGROUND: Evidence suggests that brain infiltration of lymphocytes contributes to acute neural injury after cerebral ischemia. However, the spatio-temporal dynamics of brain-infiltrating lymphocytes during the late stage after cerebral ischemia remains unclear. METHODS: C57BL/6 (B6) mice were subjected to sham, photothrombosis, or 60-min transient middle cerebral artery occlusion (MCAO) procedures. Infarct volume, neurodeficits, production of reactive oxygen species (ROS) and inflammatory factors, brain-infiltrating lymphocytes, and their activation as well as pro-inflammatory cytokine IFN-γ production were assessed...
December 15, 2017: Journal of Neuroinflammation
Sverre Vedal, Bin Han, Jia Xu, Adam Szpiro, Zhipeng Bai
No cohort studies in China on the health effects of long-term air pollution exposure have employed exposure estimates at the fine spatial scales desirable for cohort studies with individual-level health outcome data. Here we assess an array of modern air pollution exposure estimation approaches for assigning within-city exposure estimates in Beijing for individual pollutants and pollutant sources to individual members of a cohort. Issues considered in selecting specific monitoring data or new monitoring campaigns include: needed spatial resolution, exposure measurement error and its impact on health effect estimates, spatial alignment and compatibility with the cohort, and feasibility and expense...
December 15, 2017: International Journal of Environmental Research and Public Health
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