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https://www.readbyqxmd.com/read/27919235/geographical-distribution-of-typhoid-risk-factors-in-low-and-middle-income-countries
#1
Jung-Seok Lee, Vijayalaxmi V Mogasale, Vittal Mogasale, Kangsung Lee
BACKGROUND: While the global burden of typhoid fever has been often brought up for attention, the detailed surveillance information has only been available for the limited number of countries. As more efficacious vaccines will be available in the near future, it is essential to understand the geographically diverse patterns of typhoid risk levels and to prioritize the right populations for vaccination to effectively control the disease. METHODS: A composite index called the typhoid risk factor (TRF) index was created based on data with the Global Positioning System (GPS)...
December 5, 2016: BMC Infectious Diseases
https://www.readbyqxmd.com/read/27870120/continuous-attractor-network-models-of-grid-cell-firing-based-on-excitatory-inhibitory-interactions
#2
Oliver Shipston-Sharman, Lukas Solanka, Matthew F Nolan
Neurons in the medial entorhinal cortex encode location through spatial firing fields that have a grid-like organisation. The challenge of identifying mechanisms for grid firing has been addressed through experimental and theoretical investigations of medial entorhinal circuits. Here, we discuss evidence for continuous attractor network models that account for grid firing by synaptic interactions between excitatory and inhibitory cells. These models assume that grid-like firing patterns are the result of computation of location from velocity inputs, with additional spatial input required to oppose drift in the attractor state...
November 15, 2016: Journal of Physiology
https://www.readbyqxmd.com/read/27829799/diversity-and-biogeographical-patterns-of-legumes-leguminosae-indigenous-to-southern-africa
#3
Marike Trytsman, Robert H Westfall, Philippus J J Breytenbach, Frikkie J Calitz, Abraham E van Wyk
The principal aim of this study was to establish biogeographical patterns in the legume flora of southern Africa so as to facilitate the selection of species with agricultural potential. Plant collection data from the National Herbarium, South Africa, were analysed to establish the diversity and areas covered by legumes (Leguminosae/Fabaceae) indigenous to South Africa, Lesotho and Swaziland. A total of 27,322 records from 1,619 quarter degree grid cells, representing 1,580 species, 122 genera and 24 tribes were included in the analyses...
2016: PhytoKeys
https://www.readbyqxmd.com/read/27792892/preserving-privacy-whilst-maintaining-robust-epidemiological-predictions
#4
Marleen Werkman, Michael J Tildesley, Ellen Brooks-Pollock, Matt J Keeling
Mathematical models are invaluable tools for quantifying potential epidemics and devising optimal control strategies in case of an outbreak. State-of-the-art models increasingly require detailed individual farm-based and sensitive data, which may not be available due to either lack of capacity for data collection or privacy concerns. However, in many situations, aggregated data are available for use. In this study, we systematically investigate the accuracy of predictions made by mathematical models initialised with varying data aggregations, using the UK 2001 Foot-and-Mouth Disease Epidemic as a case study...
October 13, 2016: Epidemics
https://www.readbyqxmd.com/read/27792723/probabilistic-learning-by-rodent-grid-cells
#5
Allen Cheung
Mounting evidence shows mammalian brains are probabilistic computers, but the specific cells involved remain elusive. Parallel research suggests that grid cells of the mammalian hippocampal formation are fundamental to spatial cognition but their diverse response properties still defy explanation. No plausible model exists which explains stable grids in darkness for twenty minutes or longer, despite being one of the first results ever published on grid cells. Similarly, no current explanation can tie together grid fragmentation and grid rescaling, which show very different forms of flexibility in grid responses when the environment is varied...
October 2016: PLoS Computational Biology
https://www.readbyqxmd.com/read/27770476/familiarity-expands-space-and-contracts-time
#6
Anna Jafarpour, Hugo Spiers
When humans draw maps, or make judgments about travel-time, their responses are rarely accurate and are often systematically distorted. Distortion effects on estimating time to arrival and the scale of sketch-maps reveal the nature of mental representation of time and space. Inspired by data from rodent entorhinal grid cells, we predicted that familiarity to an environment would distort representations of the space by expanding the size of it. We also hypothesized that travel-time estimation would be distorted in the same direction as space-size, if time and space rely on the same cognitive map...
October 22, 2016: Hippocampus
https://www.readbyqxmd.com/read/27765433/residential-soil-and-water-radon-surveys-in-north-western-part-of-romania
#7
Alexandra Cucoş Dinu, Botond Papp, Tiberius Dicu, Mircea Moldovan, Denissa Bety Burghele, Ionuţ Tudor Moraru, Ancuţa Tenţer, Constantin Cosma
The exposure to radon and radon decay products in homes and at workplaces represents the greatest risk from natural ionizing radiation. The present study brings forward the residential, soil and water radon surveys in 5 counties of Romania. Indoor radon measurements were performed by using CR-39 track detectors exposed for 3 months on ground-floor level of dwellings, according to the NRPB Measurements Protocol. Radon concentrations in soil and water were measured using the LUK3C device. The indoor radon concentrations ranged from 5 to 2592 Bq⋅m(-3) with an updated preliminary arithmetic mean of 133 Bq⋅m(-3), and a geometric mean of 90 Bq⋅m(-3)...
January 2017: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/27764662/grid-cells-for-conceptual-spaces
#8
Nikolaus Kriegeskorte, Katherine R Storrs
"Grid cells" encode an animal's location and direction of movement in 2D physical environments via regularly repeating receptive fields. Constantinescu et al. (2016) report the first evidence of grid cells for 2D conceptual spaces. The work has exciting implications for mental representation and shows how detailed neural-coding hypotheses can be tested with bulk population-activity measures.
October 19, 2016: Neuron
https://www.readbyqxmd.com/read/27764597/on-decoding-grid-cell-population-codes-using-approximate-belief-propagation
#9
Yongseok Yoo, Woori Kim
Neural systems are inherently noisy. One well-studied example of a noise reduction mechanism in the brain is the population code, where representing a variable with multiple neurons allows the encoded variable to be recovered with fewer errors. Studies have assumed ideal observer models for decoding population codes, and the manner in which information in the neural population can be retrieved remains elusive. This letter addresses a mechanism by which realistic neural circuits can recover encoded variables...
October 20, 2016: Neural Computation
https://www.readbyqxmd.com/read/27764589/a-combinatorial-model-for-dentate-gyrus-sparse-coding
#10
William Severa, Ojas Parekh, Conrad D James, James B Aimone
The dentate gyrus forms a critical link between the entorhinal cortex and CA3 by providing a sparse version of the signal. Concurrent with this increase in sparsity, a widely accepted theory suggests the dentate gyrus performs pattern separation-similar inputs yield decorrelated outputs. Although an active region of study and theory, few logically rigorous arguments detail the dentate gyrus's (DG) coding. We suggest a theoretically tractable, combinatorial model for this action. The model provides formal methods for a highly redundant, arbitrarily sparse, and decorrelated output signal...
October 20, 2016: Neural Computation
https://www.readbyqxmd.com/read/27756084/-network-analyses-in-regional-health-care-research-example-of-dermatological-care-in-the-metropolitan-region-of-hamburg
#11
J Augustin, J Austermann, S Erasmi
Background: One of the overall objectives of the legislator is to ensure an overall "homogeneous", and easily accessible medical care for the population. The physician-patient ratio can be used to describe the regional health care situation. But this method does not provide information concerning the availability of, for instance, the nearest doctor. Therefore, further parameters such as accessibility must be taken into consideration. For this purpose, network analyses are an appropriate method. The objective of this study is to present methodological tools to evaluate the healthcare situation in the metropolitan region of Hamburg, primarily focusing on accessibility using dermatologists as an example...
October 18, 2016: Das Gesundheitswesen
https://www.readbyqxmd.com/read/27755764/evaluation-of-downscaled-gridded-climate-data-for-the-conterminous-united-states
#12
R Behnke, S Vavrus, A Allstadt, T Albright, W E Thogmartin, V C Radeloff
Weather and climate affect many ecological processes, making spatially continuous yet fine-resolution weather data desirable for ecological research and predictions. Numerous downscaled weather data sets exist, but little attempt has been made to evaluate them systematically. Here we address this shortcoming by focusing on four major questions: (1) How accurate are downscaled, gridded climate data sets in terms of temperature and precipitation estimates? (2) Are there significant regional differences in accuracy among data sets? (3) How accurate are their mean values compared with extremes? (4) Does their accuracy depend on spatial resolution? We compared eight widely used downscaled data sets that provide gridded daily weather data for recent decades across the United States...
July 2016: Ecological Applications: a Publication of the Ecological Society of America
https://www.readbyqxmd.com/read/27688742/mapping-paddy-rice-planting-area-in-rice-wetland-coexistent-areas-through-analysis-of-landsat-8-oli-and-modis-images
#13
Yuting Zhou, Xiangming Xiao, Yuanwei Qin, Jinwei Dong, Geli Zhang, Weili Kou, Cui Jin, Jie Wang, Xiangping Li
Accurate and up-to-date information on the spatial distribution of paddy rice fields is necessary for the studies of trace gas emissions, water source management, and food security. The phenology-based paddy rice mapping algorithm, which identifies the unique flooding stage of paddy rice, has been widely used. However, identification and mapping of paddy rice in rice-wetland coexistent areas is still a challenging task. In this study, we found that the flooding/transplanting periods of paddy rice and natural wetlands were different...
April 2016: International Journal of Applied Earth Observation and Geoinformation: ITC Journal
https://www.readbyqxmd.com/read/27677935/potential-roles-of-cholinergic-modulation-in-the-neural-coding-of-location-and-movement-speed
#14
Holger Dannenberg, James R Hinman, Michael E Hasselmo
Behavioral data suggest that cholinergic modulation may play a role in certain aspects of spatial memory, and neurophysiological data demonstrate neurons that fire in response to spatial dimensions, including grid cells and place cells that respond on the basis of location and running speed. These neurons show firing responses that depend upon the visual configuration of the environment, due to coding in visually-responsive regions of the neocortex. This review focuses on the physiological effects of acetylcholine that may influence the sensory coding of spatial dimensions relevant to behavior...
September 24, 2016: Journal of Physiology, Paris
https://www.readbyqxmd.com/read/27648241/large-scale-dark-diversity-estimates-new-perspectives-with-combined-methods
#15
Argo Ronk, Francesco de Bello, Pavel Fibich, Meelis Pärtel
Large-scale biodiversity studies can be more informative if observed diversity in a study site is accompanied by dark diversity, the set of absent although ecologically suitable species. Dark diversity methodology is still being developed and a comparison of different approaches is needed. We used plant data at two different scales (European and seven large regions) and compared dark diversity estimates from two mathematical methods: species co-occurrence (SCO) and species distribution modeling (SDM). We used plant distribution data from the Atlas Florae Europaeae (50 × 50 km grid cells) and seven different European regions (10 × 10 km grid cells)...
September 2016: Ecology and Evolution
https://www.readbyqxmd.com/read/27645529/assessment-of-hydration-thermodynamics-at-protein-interfaces-with-grid-cell-theory
#16
Georgios Gerogiokas, Michelle W Y Southey, Michael P Mazanetz, Alexander Heifetz, Michael Bodkin, Richard J Law, Richard H Henchman, J Michel
Molecular dynamics simulations have been analyzed with the Grid Cell Theory (GCT) method to spatially resolve the binding enthalpies and entropies of water molecules at the interface of 17 structurally diverse proteins. Correlations between computed energetics and structural descriptors have been sought to facilitate the development of simple models of protein hydration. Little correlation was found between GCT-computed binding enthalpies and continuum electrostatics calculations. A simple count of contacts with functional groups in charged amino acids correlates well with enhanced water stabilization, but the stability of water near hydrophobic and polar residues depends markedly on its coordination environment...
October 13, 2016: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/27631131/testing-the-efficacy-of-global-biodiversity-hotspots-for-insect-conservation-the-case-of-south-african-katydids
#17
Corinna S Bazelet, Aileen C Thompson, Piotr Naskrecki
The use of endemism and vascular plants only for biodiversity hotspot delineation has long been contested. Few studies have focused on the efficacy of global biodiversity hotspots for the conservation of insects, an important, abundant, and often ignored component of biodiversity. We aimed to test five alternative diversity measures for hotspot delineation and examine the efficacy of biodiversity hotspots for conserving a non-typical target organism, South African katydids. Using a 1° fishnet grid, we delineated katydid hotspots in two ways: (1) count-based: grid cells in the top 10% of total, endemic, threatened and/or sensitive species richness; vs...
2016: PloS One
https://www.readbyqxmd.com/read/27613436/distant-space-processing-is-controlled-by-tpa-dependent-nmda-receptor-signaling-in-the-entorhinal-cortex
#18
Marie Hébert, Antoine Anfray, Arnaud Chevilley, Sara Martinez de Lizarrondo, Aurélien Quenault, Morgane Louessard, Benoit D Roussel, Pauline Obiang, Etienne Save, Cyrille Orset, Eric Maubert, Denis Vivien, Véronique Agin
In humans, spatial cognition and navigation impairments are a frequent situation during physiological and pathological aging, leading to a dramatic deterioration in the quality of life. Despite the discovery of neurons with location-specific activity in rodents, that is, place cells in the hippocampus and later on grid cells in the entorhinal cortex (EC), the molecular mechanisms underlying spatial cognition are still poorly known. Our present data bring together in an unusual combination 2 molecules of primary biological importance: a major neuronal excitatory receptor, N-methyl-D-aspartate receptor (NMDAR), and an extracellular protease, tissue plasminogen activator (tPA), in the control of spatial navigation...
September 9, 2016: Cerebral Cortex
https://www.readbyqxmd.com/read/27586717/incorporating-directivity-in-the-fourier-pseudospectral-time-domain-method-using-spherical-harmonics
#19
Fotis Georgiou, Maarten Hornikx
The pseudospectral time-domain method (PSTD) provides an efficient way to solve the linear acoustics equations. With regards to acoustic modeling and auralization, source directivity as well as head-related directivity have a clear influence on the perceived sound field and have to be included in computations. In this paper directive sources are implemented in the time-domain method PSTD. First, a given frequency dependent source directivity is decomposed onto spherical harmonic functions. The directive source is then implemented through spatial distributions in PSTD that relate to the spherical harmonic functions, and time-dependent functions are assigned to the spatial distributions in order to obtain the frequency content of the directivity...
August 2016: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/27572056/grid-cell-representations-in-mental-simulation
#20
Jacob Ls Bellmund, Lorena Deuker, Tobias Navarro Schröder, Christian F Doeller
Anticipating the future is a key motif of the brain, possibly supported by mental simulation of upcoming events. Rodent single-cell recordings suggest the ability of spatially tuned cells to represent subsequent locations. Grid-like representations have been observed in the human entorhinal cortex during virtual and imagined navigation. However, hitherto it remains unknown if grid-like representations contribute to mental simulation in the absence of imagined movement. Participants imagined directions between building locations in a large-scale virtual-reality city while undergoing fMRI without re-exposure to the environment...
August 30, 2016: ELife
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