Science.gov

Sample records for impaired remote spatial

  1. Chronic ethanol consumption impairs spatial remote memory in rats but does not affect cortical cholinergic parameters.

    PubMed

    Pereira, S R; Menezes, G A; Franco, G C; Costa, A E; Ribeiro, A M

    1998-06-01

    We have studied learning, memory and cortical cholinergic parameters after oral administration of 20% v/v ethanol solution to male Fisher rats for 6 months. A group of rats were trained to behave efficiently in an eight-arm radial maze and after that split into two subgroups submitted to ethanol or control treatment. Ethanol-treated rats had more difficulty in relearning the same task 1 year later, compared to ethanol-untreated rats (control). Differences in working memory performance were found, but only in the first 10 training sessions. Another group of rats, which had not been pretrained, was also split into two subgroups submitted to ethanol or control treatment. After that, these rats were trained in the radial maze task for the first time. No significant difference was found between the reference memory performance of the untreated subgroup and the treated one. These two subgroups did not significantly differ in their working memory performance either. Moreover, there were no significant differences between treated and control subjects in the following biochemical brain cortical parameters: in vitro acetylcholinesterase (AChE) activity, and stimulated acetylcholine (ACh) release. This work presents an experimental design that allows assessment of remote memory performance after ethanol chronic consumption and shows that the experimental subject is able to retain the behaviors learned 1 year before. It was concluded that chronic ethanol treatment may cause retrograde amnesia, which does not seem to be linked with a cortical cholinergic deficit. PMID:9632211

  2. Abnormal social behavior, hyperactivity, impaired remote spatial memory, and increased D1-mediated dopaminergic signaling in neuronal nitric oxide synthase knockout mice

    PubMed Central

    Tanda, Koichi; Nishi, Akinori; Matsuo, Naoki; Nakanishi, Kazuo; Yamasaki, Nobuyuki; Sugimoto, Tohru; Toyama, Keiko; Takao, Keizo; Miyakawa, Tsuyoshi

    2009-01-01

    Background Neuronal nitric oxide synthase (nNOS) is involved in the regulation of a diverse population of intracellular messenger systems in the brain. In humans, abnormal NOS/nitric oxide metabolism is suggested to contribute to the pathogenesis and pathophysiology of some neuropsychiatric disorders, such as schizophrenia and bipolar disorder. Mice with targeted disruption of the nNOS gene exhibit abnormal behaviors. Here, we subjected nNOS knockout (KO) mice to a battery of behavioral tests to further investigate the role of nNOS in neuropsychiatric functions. We also examined the role of nNOS in dopamine/DARPP-32 signaling in striatal slices from nNOS KO mice and the effects of the administration of a dopamine D1 receptor agonist on behavior in nNOS KO mice. Results nNOS KO mice showed hyperlocomotor activity in a novel environment, increased social interaction in their home cage, decreased depression-related behavior, and impaired spatial memory retention. In striatal slices from nNOS KO mice, the effects of a dopamine D1 receptor agonist, SKF81297, on the phosphorylation of DARPP-32 and AMPA receptor subunit GluR1 at protein kinase A sites were enhanced. Consistent with the biochemical results, intraperitoneal injection of a low dose of SKF81297 significantly decreased prepulse inhibition in nNOS KO mice, but not in wild-type mice. Conclusion These findings indicate that nNOS KO upregulates dopamine D1 receptor signaling, and induces abnormal social behavior, hyperactivity and impaired remote spatial memory. nNOS KO mice may serve as a unique animal model of psychiatric disorders. PMID:19538708

  3. Remote state preparation of spatial qubits

    SciTech Connect

    Solis-Prosser, M. A.; Neves, L.

    2011-07-15

    We study the quantum communication protocol of remote state preparation (RSP) for pure states of qubits encoded in single photons transmitted through a double slit, the so-called spatial qubits. Two measurement strategies that one can adopt to remotely prepare the states are discussed. The first strategy is the well-known spatial postselection, where a single-pixel detector measures the transverse position of the photon between the focal and the image plane of a lens. The second strategy, proposed by ourselves, is a generalized measurement divided into two steps: the implementation of a two-outcome positive operator-valued measurement (POVM) followed by the spatial postselection at the focal plane of the lens by a two-pixel detector in each output of the POVM. In both cases we analyze the effects of the finite spatial resolution of the detectors over three figures of merit of the protocol, namely, the probability of preparation, the fidelity, and purity of the remotely prepared states. It is shown that our strategy improves these figures compared with spatial postselection, at the expense of increasing the classical communication cost as well as the required experimental resources. In addition, we present a modified version of our strategy for RSP of spatial qudits which is able to prepare arbitrary pure states, unlike spatial postselection alone. We expect that our study may also be extended for RSP of the angular spectrum of a single-photon field as an alternative for quantum teleportation which requires very inefficient nonlinear interactions.

  4. Impaired allocentric spatial memory underlying topographical disorientation.

    PubMed

    Burgess, Neil; Trinkler, Iris; King, John; Kennedy, Angus; Cipolotti, Lisa

    2006-01-01

    The cognitive processes supporting spatial navigation are considered in the context of a patient (CF) with possible very early Alzheimer's disease who presents with topographical disorientation. Her verbal memory and her recognition memory for unknown buildings, landmarks and outdoor scenes was intact, although she showed an impairment in face processing. By contrast, her navigational ability, quantitatively assessed within a small virtual reality (VR) town, was significantly impaired. Interestingly, she showed a selective impairment in a VR object-location memory test whenever her viewpoint was shifted between presentation and test, but not when tested from the same viewpoint. We suggest that a specific impairment in locating objects relative to the environment rather than relative to the perceived viewpoint (i.e. allocentric rather than egocentric spatial memory) underlies her topographical disorientation. We discuss the likely neural bases of this deficit in the light of related studies in humans and animals, focusing on the hippocampus and related areas. The specificity of our test indicates a new way of assessing topographical disorientation, with possible application to the assessment of progressive dementias such as Alzheimer's disease. PMID:16703955

  5. Loss of form vision impairs spatial imagery

    PubMed Central

    Occelli, Valeria; Lin, Jonathan B.; Lacey, Simon; Sathian, K.

    2014-01-01

    Previous studies have reported inconsistent results when comparing spatial imagery performance in the blind and the sighted, with some, but not all, studies demonstrating deficits in the blind. Here, we investigated the effect of visual status and individual preferences (“cognitive style”) on performance of a spatial imagery task. Participants with blindness resulting in the loss of form vision at or after age 6, and age- and gender-matched sighted participants, performed a spatial imagery task requiring memorization of a 4 × 4 lettered matrix and subsequent mental construction of shapes within the matrix from four-letter auditory cues. They also completed the Santa Barbara Sense of Direction Scale (SBSoDS) and a self-evaluation of cognitive style. The sighted participants also completed the Object-Spatial Imagery and Verbal Questionnaire (OSIVQ). Visual status affected performance on the spatial imagery task: the blind performed significantly worse than the sighted, independently of the age at which form vision was completely lost. Visual status did not affect the distribution of preferences based on self-reported cognitive style. Across all participants, self-reported verbalizer scores were significantly negatively correlated with accuracy on the spatial imagery task. There was a positive correlation between the SBSoDS score and accuracy on the spatial imagery task, across all participants, indicating that a better sense of direction is related to a more proficient spatial representation and that the imagery task indexes ecologically relevant spatial abilities. Moreover, the older the participants were, the worse their performance was, indicating a detrimental effect of age on spatial imagery performance. Thus, spatial skills represent an important target for rehabilitative approaches to visual impairment, and individual differences, which can modulate performance, should be taken into account in such approaches. PMID:24678294

  6. Loss of form vision impairs spatial imagery.

    PubMed

    Occelli, Valeria; Lin, Jonathan B; Lacey, Simon; Sathian, K

    2014-01-01

    Previous studies have reported inconsistent results when comparing spatial imagery performance in the blind and the sighted, with some, but not all, studies demonstrating deficits in the blind. Here, we investigated the effect of visual status and individual preferences ("cognitive style") on performance of a spatial imagery task. Participants with blindness resulting in the loss of form vision at or after age 6, and age- and gender-matched sighted participants, performed a spatial imagery task requiring memorization of a 4 × 4 lettered matrix and subsequent mental construction of shapes within the matrix from four-letter auditory cues. They also completed the Santa Barbara Sense of Direction Scale (SBSoDS) and a self-evaluation of cognitive style. The sighted participants also completed the Object-Spatial Imagery and Verbal Questionnaire (OSIVQ). Visual status affected performance on the spatial imagery task: the blind performed significantly worse than the sighted, independently of the age at which form vision was completely lost. Visual status did not affect the distribution of preferences based on self-reported cognitive style. Across all participants, self-reported verbalizer scores were significantly negatively correlated with accuracy on the spatial imagery task. There was a positive correlation between the SBSoDS score and accuracy on the spatial imagery task, across all participants, indicating that a better sense of direction is related to a more proficient spatial representation and that the imagery task indexes ecologically relevant spatial abilities. Moreover, the older the participants were, the worse their performance was, indicating a detrimental effect of age on spatial imagery performance. Thus, spatial skills represent an important target for rehabilitative approaches to visual impairment, and individual differences, which can modulate performance, should be taken into account in such approaches. PMID:24678294

  7. Spatial reasoning in remotely sensed data

    NASA Technical Reports Server (NTRS)

    Campbell, J.; Ehrich, R. W.; Elliott, D.; Haralick, R. M.; Wang, S.

    1981-01-01

    Photointerpreters employ a variety of implicit spatial models to provide interpretations from remotely sensed aerial or satellite imagery. In this paper one application is illustrated: how ridges and valleys can be automatically interpreted from Landsat imagery of a mountainous area, and how a relative elevation terrain model can be constructed from this interpretation. How to examine valleys for the possible presence of streams or rivers is shown, and how a spatial relational model can be set up to make a final interpretation of the river drainage network is explored.

  8. Metasurface Spatial Processor for Electromagnetic Remote Control

    NASA Astrophysics Data System (ADS)

    Achouri, Karim; Lavigne, Guillaume; Salem, Mohamed A.; Caloz, Christophe

    2016-05-01

    We introduce the concept of metasurface spatial processor, whose transmission is remotely and coherently controlled by the superposition of an incident wave and a control wave through the metasurface. The conceptual operation of this device is analogous to both that of a transistor and a Mach-Zehnder interferometer, while offering much more diversity in terms of electromagnetic transformations. We demonstrate two metasurfaces, that perform the operation of electromagnetic switching and amplification.

  9. Spatial Inference for Distributed Remote Sensing Data

    NASA Astrophysics Data System (ADS)

    Braverman, A. J.; Katzfuss, M.; Nguyen, H.

    2014-12-01

    Remote sensing data are inherently spatial, and a substantial portion of their value for scientific analyses derives from the information they can provide about spatially dependent processes. Geophysical variables such as atmopsheric temperature, cloud properties, humidity, aerosols and carbon dioxide all exhibit spatial patterns, and satellite observations can help us learn about the physical mechanisms driving them. However, remote sensing observations are often noisy and incomplete, so inferring properties of true geophysical fields from them requires some care. These data can also be massive, which is both a blessing and a curse: using more data drives uncertainties down, but also drives costs up, particularly when data are stored on different computers or in different physical locations. In this talk I will discuss a methodology for spatial inference on massive, distributed data sets that does not require moving large volumes of data. The idea is based on a combination of ideas including modeling spatial covariance structures with low-rank covariance matrices, and distributed estimation in sensor or wireless networks.

  10. Spatial Coding of Individuals with Visual Impairments

    ERIC Educational Resources Information Center

    Papadopoulos, Konstantinos; Koustriava, Eleni; Kartasidou, Lefkothea

    2012-01-01

    The aim of this study is to examine the ability of children and adolescents with visual impairments to code and represent near space. Moreover, it examines the impact of the strategies they use and individual differences in their performance. A total of 30 individuals with visual impairments up to the age of 18 were given eight different object…

  11. Auditory spatial localization: Developmental delay in children with visual impairments.

    PubMed

    Cappagli, Giulia; Gori, Monica

    2016-01-01

    For individuals with visual impairments, auditory spatial localization is one of the most important features to navigate in the environment. Many works suggest that blind adults show similar or even enhanced performance for localization of auditory cues compared to sighted adults (Collignon, Voss, Lassonde, & Lepore, 2009). To date, the investigation of auditory spatial localization in children with visual impairments has provided contrasting results. Here we report, for the first time, that contrary to visually impaired adults, children with low vision or total blindness show a significant impairment in the localization of static sounds. These results suggest that simple auditory spatial tasks are compromised in children, and that this capacity recovers over time. PMID:27002960

  12. Impairment of auditory spatial localization in congenitally blind human subjects.

    PubMed

    Gori, Monica; Sandini, Giulio; Martinoli, Cristina; Burr, David C

    2014-01-01

    Several studies have demonstrated enhanced auditory processing in the blind, suggesting that they compensate their visual impairment in part with greater sensitivity of the other senses. However, several physiological studies show that early visual deprivation can impact negatively on auditory spatial localization. Here we report for the first time severely impaired auditory localization in the congenitally blind: thresholds for spatially bisecting three consecutive, spatially-distributed sound sources were seriously compromised, on average 4.2-fold typical thresholds, and half performing at random. In agreement with previous studies, these subjects showed no deficits on simpler auditory spatial tasks or with auditory temporal bisection, suggesting that the encoding of Euclidean auditory relationships is specifically compromised in the congenitally blind. It points to the importance of visual experience in the construction and calibration of auditory spatial maps, with implications for rehabilitation strategies for the congenitally blind. PMID:24271326

  13. Impairment of auditory spatial localization in congenitally blind human subjects

    PubMed Central

    Gori, Monica; Sandini, Giulio; Martinoli, Cristina

    2014-01-01

    Several studies have demonstrated enhanced auditory processing in the blind, suggesting that they compensate their visual impairment in part with greater sensitivity of the other senses. However, several physiological studies show that early visual deprivation can impact negatively on auditory spatial localization. Here we report for the first time severely impaired auditory localization in the congenitally blind: thresholds for spatially bisecting three consecutive, spatially-distributed sound sources were seriously compromised, on average 4.2-fold typical thresholds, and half performing at random. In agreement with previous studies, these subjects showed no deficits on simpler auditory spatial tasks or with auditory temporal bisection, suggesting that the encoding of Euclidean auditory relationships is specifically compromised in the congenitally blind. It points to the importance of visual experience in the construction and calibration of auditory spatial maps, with implications for rehabilitation strategies for the congenitally blind. PMID:24271326

  14. Impaired spatial working memory maintenance in schizophrenia involves both spatial coordinates and spatial reference frames.

    PubMed

    Mazhari, Shahrzad; Badcock, Johanna C; Waters, Flavie A; Dragović, Milan; Badcock, David R; Jablensky, Assen

    2010-10-30

    Spatial working memory (SWM) dysfunction is a central finding in schizophrenia; however, more evidence of impaired maintenance over time is required. Consequently, the present study examined SWM maintenance over short unfilled delays, and with encoding equated. The influence of a vertical reference frame to support maintenance was also investigated. The performance of 58 patients with schizophrenia and 50 healthy controls was assessed using the Visuo-Spatial Working Memory (VSWM) Test across three unfilled delays (0, 2, and 4s). Inaccuracy of direction and distance responses was examined at each delay duration. The results showed that performance was significantly less accurate for both distance and direction responses at 2 and 4s delays in schizophrenia, but was not significantly different from controls at the 0s delay. Patients showed a particularly marked loss of accuracy between the time interval of 0-2s. Furthermore, schizophrenia participants exhibited significantly greater response variability at the vertical axis of symmetry than controls at the 2 and 4s delays, but not at the 0s delay. These data clearly show both impaired maintenance over time and difficulty using a vertical frame of reference in schizophrenia. The latter findings may reflect, in part, dysfunctional reference-related inhibition. PMID:20493553

  15. Spatial navigation impairment is proportional to right hippocampal volume

    PubMed Central

    Nedelska, Zuzana; Andel, Ross; Laczó, Jan; Vlcek, Kamil; Horinek, Daniel; Lisy, Jiri; Sheardova, Katerina; Bureš, Jan; Hort, Jakub

    2012-01-01

    Cognitive deficits in older adults attributable to Alzheimer's disease (AD) pathology are featured early on by hippocampal impairment. Among these individuals, deterioration in spatial navigation, manifested by poor hippocampus-dependent allocentric navigation, may occur well before the clinical onset of dementia. Our aim was to determine whether allocentric spatial navigation impairment would be proportional to right hippocampal volume loss irrespective of general brain atrophy. We also contrasted the respective spatial navigation scores of the real-space human Morris water maze with its corresponding 2D computer version. We included 42 cognitively impaired patients with either amnestic mild cognitive impairment (n = 23) or mild and moderate AD (n = 19), and 14 cognitively intact older controls. All participants underwent 1.5T MRI brain scanning with subsequent automatic measurement of the total brain and hippocampal (right and left) volumes. Allocentric spatial navigation was tested in the real-space version of the human Morris water maze and in its corresponding computer version. Participants used two navigational cues to locate an invisible goal independent of the start position. We found that smaller right hippocampal volume was associated with poorer navigation performance in both the real-space (β = −0.62, P < 0.001) and virtual (β = −0.43, P = 0.026) versions, controlling for demographic variables, total brain and left hippocampal volumes. In subsequent analyses, the results were significant in cognitively impaired (P ≤ 0.05) but not in cognitively healthy (P > 0.59) subjects. The respective real-space and virtual scores strongly correlated with each other. Our findings indicate that the right hippocampus plays a critical role in allocentric navigation, particularly when cognitive impairment is present. PMID:22308496

  16. Impaired allocentric spatial processing in posttraumatic stress disorder

    PubMed Central

    Smith, Kirsten V.; Burgess, Neil; Brewin, Chris R.; King, John A.

    2015-01-01

    A neurobiological dual representation model of PTSD proposes that reduced hippocampus-dependent contextual processing contributes to intrusive imagery due to a loss of control over hippocampus-independent sensory and affective representations. We investigated whether PTSD sufferers show impaired allocentric spatial processing indicative of reduced hippocampal functioning. Trauma-exposed individuals with (N = 29) and without (N = 30) a diagnosis of PTSD completed two tests of spatial processing: a topographical recognition task comprising perceptual and memory components, and a test of memory for objects’ locations within a virtual environment in which the test is from either the same viewpoint as presentation (solvable with egocentric memory) or a different viewpoint (requiring allocentric memory). Participants in the PTSD group performed significantly worse on allocentric spatial processing than trauma-exposed controls. Groups performed comparably on egocentric memory and non-spatial memory for lists of objects. Exposure to repeated incident trauma was also associated with significantly worse spatial processing in the PTSD group. Results show a selective impairment in allocentric spatial processing, implicating weak hippocampal functioning, as predicted by a neurobiological dual representation model of PTSD. These findings have important clinical implications for cognitive therapy. PMID:25636201

  17. Impaired allocentric spatial processing in posttraumatic stress disorder.

    PubMed

    Smith, Kirsten V; Burgess, Neil; Brewin, Chris R; King, John A

    2015-03-01

    A neurobiological dual representation model of PTSD proposes that reduced hippocampus-dependent contextual processing contributes to intrusive imagery due to a loss of control over hippocampus-independent sensory and affective representations. We investigated whether PTSD sufferers show impaired allocentric spatial processing indicative of reduced hippocampal functioning. Trauma-exposed individuals with (N=29) and without (N=30) a diagnosis of PTSD completed two tests of spatial processing: a topographical recognition task comprising perceptual and memory components, and a test of memory for objects' locations within a virtual environment in which the test is from either the same viewpoint as presentation (solvable with egocentric memory) or a different viewpoint (requiring allocentric memory). Participants in the PTSD group performed significantly worse on allocentric spatial processing than trauma-exposed controls. Groups performed comparably on egocentric memory and non-spatial memory for lists of objects. Exposure to repeated incident trauma was also associated with significantly worse spatial processing in the PTSD group. Results show a selective impairment in allocentric spatial processing, implicating weak hippocampal functioning, as predicted by a neurobiological dual representation model of PTSD. These findings have important clinical implications for cognitive therapy. PMID:25636201

  18. Fractals and Spatial Methods for Mining Remote Sensing Imagery

    NASA Technical Reports Server (NTRS)

    Lam, Nina; Emerson, Charles; Quattrochi, Dale

    2003-01-01

    The rapid increase in digital remote sensing and GIS data raises a critical problem -- how can such an enormous amount of data be handled and analyzed so that useful information can be derived quickly? Efficient handling and analysis of large spatial data sets is central to environmental research, particularly in global change studies that employ time series. Advances in large-scale environmental monitoring and modeling require not only high-quality data, but also reliable tools to analyze the various types of data. A major difficulty facing geographers and environmental scientists in environmental assessment and monitoring is that spatial analytical tools are not easily accessible. Although many spatial techniques have been described recently in the literature, they are typically presented in an analytical form and are difficult to transform to a numerical algorithm. Moreover, these spatial techniques are not necessarily designed for remote sensing and GIS applications, and research must be conducted to examine their applicability and effectiveness in different types of environmental applications. This poses a chicken-and-egg problem: on one hand we need more research to examine the usability of the newer techniques and tools, yet on the other hand, this type of research is difficult to conduct if the tools to be explored are not accessible. Another problem that is fundamental to environmental research are issues related to spatial scale. The scale issue is especially acute in the context of global change studies because of the need to integrate remote-sensing and other spatial data that are collected at different scales and resolutions. Extrapolation of results across broad spatial scales remains the most difficult problem in global environmental research. There is a need for basic characterization of the effects of scale on image data, and the techniques used to measure these effects must be developed and implemented to allow for a multiple scale assessment of

  19. Spatial uncertainty in remote sensing generated hydrological variables

    NASA Astrophysics Data System (ADS)

    Mendiguren González, Gorka; Stisen, Simon

    2016-04-01

    The use of satellite remote sensing (RS) has proven its potential to generate different hydrological variables such as Land Surface Temperature (LST), Leaf Area Index (LAI) or Evapotranspiration (ET) among others. In the case of ET different methods combine spectral and thermal information to estimate Actual ET (aET) coincident with satellite overpass. These estimates from space has become popular in the hydrological modeling community. The information obtained from RS estimates can be used to calibrate and validate hydrological models not just at single points or catchment averages, but also the simulated spatial patterns. It is a common assumption that although the RS estimates are uncertain, their strength lies in the spatial pattern information, due to the unprecedented spatial coverage of the observations. When spatial patterns obtained from remote sensing estimates are intended for evaluating the spatial patterns of distributed hydrological models, it will however be necessary to challenge that assumption. This study aims at quantifying the uncertainty of the estimated spatial pattern of temporally aggregated monthly LST and AET maps derived from the MODIS satellite. The proposed approach is based on a cluster analysis performed on hundreds of possible realizations of the estimates generated by sampling within the uncertainty of the individual pixels estimates and taking into account temporal variation and the correlation length of the error. The result is not only monthly maps of LST and AET, but also maps of the uncertainty of the spatial pattern. This type of information is critical when evaluating the spatial pattern performance of hydrological models, because the performance criteria can be adjusted for areas of high and low confidence in the observational data set. The resulting maps are finally utilized for an evaluation of the spatial performance of the 43,000 km2 national hydrological model of Denmark.

  20. A high fructose diet impairs spatial memory in male rats.

    PubMed

    Ross, A P; Bartness, T J; Mielke, J G; Parent, M B

    2009-10-01

    Over the past three decades there has been a substantial increase in the amount of fructose consumed by North Americans. Recent evidence from rodents indicates that hippocampal insulin signaling facilitates memory and excessive fructose consumption produces hippocampal insulin resistance. Based on this evidence, the present study tested the hypothesis that a high fructose diet would impair hippocampal-dependent memory. Adult male Sprague-Dawley rats (postnatal day 61) were fed either a control (0% fructose) or high fructose diet (60% of calories). Food intake and body mass were measured regularly. After 19 weeks, the rats were given 3 days of training (8 trials/day) in a spatial version of the water maze task, and retention performance was probed 48 h later. The high fructose diet did not affect acquisition of the task, but did impair performance on the retention test. Specifically, rats fed a high fructose diet displayed significantly longer latencies to reach the area where the platform had been located, made significantly fewer approaches to that area, and spent significantly less time in the target quadrant than did control diet rats. There was no difference in swim speed between the two groups. The retention deficits correlated significantly with fructose-induced elevations of plasma triglyceride concentrations. Consequently, the impaired spatial water maze retention performance seen with the high fructose diet may have been attributable, at least in part, to fructose-induced increases in plasma triglycerides. PMID:19500683

  1. Encoding audio motion: spatial impairment in early blind individuals.

    PubMed

    Finocchietti, Sara; Cappagli, Giulia; Gori, Monica

    2015-01-01

    The consequence of blindness on auditory spatial localization has been an interesting issue of research in the last decade providing mixed results. Enhanced auditory spatial skills in individuals with visual impairment have been reported by multiple studies, while some aspects of spatial hearing seem to be impaired in the absence of vision. In this study, the ability to encode the trajectory of a 2-dimensional sound motion, reproducing the complete movement, and reaching the correct end-point sound position, is evaluated in 12 early blind (EB) individuals, 8 late blind (LB) individuals, and 20 age-matched sighted blindfolded controls. EB individuals correctly determine the direction of the sound motion on the horizontal axis, but show a clear deficit in encoding the sound motion in the lower side of the plane. On the contrary, LB individuals and blindfolded controls perform much better with no deficit in the lower side of the plane. In fact the mean localization error resulted 271 ± 10 mm for EB individuals, 65 ± 4 mm for LB individuals, and 68 ± 2 mm for sighted blindfolded controls. These results support the hypothesis that (i) it exists a trade-off between the development of enhanced perceptual abilities and role of vision in the sound localization abilities of EB individuals, and (ii) the visual information is fundamental in calibrating some aspects of the representation of auditory space in the brain. PMID:26441733

  2. Automated Verification of Spatial Resolution in Remotely Sensed Imagery

    NASA Technical Reports Server (NTRS)

    Davis, Bruce; Ryan, Robert; Holekamp, Kara; Vaughn, Ronald

    2011-01-01

    Image spatial resolution characteristics can vary widely among sources. In the case of aerial-based imaging systems, the image spatial resolution characteristics can even vary between acquisitions. In these systems, aircraft altitude, speed, and sensor look angle all affect image spatial resolution. Image spatial resolution needs to be verified with estimators that include the ground sample distance (GSD), the modulation transfer function (MTF), and the relative edge response (RER), all of which are key components of image quality, along with signal-to-noise ratio (SNR) and dynamic range. Knowledge of spatial resolution parameters is important to determine if features of interest are distinguishable in imagery or associated products, and to develop image restoration algorithms. An automated Spatial Resolution Verification Tool (SRVT) was developed to rapidly determine the spatial resolution characteristics of remotely sensed aerial and satellite imagery. Most current methods for assessing spatial resolution characteristics of imagery rely on pre-deployed engineered targets and are performed only at selected times within preselected scenes. The SRVT addresses these insufficiencies by finding uniform, high-contrast edges from urban scenes and then using these edges to determine standard estimators of spatial resolution, such as the MTF and the RER. The SRVT was developed using the MATLAB programming language and environment. This automated software algorithm assesses every image in an acquired data set, using edges found within each image, and in many cases eliminating the need for dedicated edge targets. The SRVT automatically identifies high-contrast, uniform edges and calculates the MTF and RER of each image, and when possible, within sections of an image, so that the variation of spatial resolution characteristics across the image can be analyzed. The automated algorithm is capable of quickly verifying the spatial resolution quality of all images within a data

  3. Spatial reversal learning is impaired by age in pet dogs.

    PubMed

    Mongillo, Paolo; Araujo, Joseph A; Pitteri, Elisa; Carnier, Paolo; Adamelli, Serena; Regolin, Lucia; Marinelli, Lieta

    2013-12-01

    Aged dogs spontaneously develop progressive decline in both cognitive and behavioral function, in addition to neuropathological changes, that collectively parallel several aspects of human aging and Alzheimer's disease progression and likely contribute to the development of canine cognitive dysfunction syndrome. In the current study, ethologically relevant spatial learning, retention, and reversal learning tasks were conducted, with the goal of expanding canine neuropsychological testing to pet dogs. Initially, dogs (N = 44, aged 7.8 ± 2.8 years, mean ± SD) had to learn which of two alternative routes successfully led out of a T-maze. Two weeks later, long-term memory retention was assessed, immediately followed by a reversal learning task in which the previously correct route out of the maze was reversed compared with the initial learning and memory retention tasks. No effects of age were evident on the learning or retention tasks. However, older (≥ 8 years) dogs were significantly impaired on the reversal learning task compared with younger ones (< 8 years). Moreover, trial response latency was significantly increased in aged dogs across both the initial and reversal learning tasks but not on the retention task, which suggests that processing speed was impaired by increasing age during the acquisition of novel spatial information but not during performance of previously learned responses. Overall, the current study provides a framework for assessing cognitive function in pet dogs, which should improve understanding of the effects of aging on cognition in the dog population. PMID:23529504

  4. Spatial and Temporal Scaling of Thermal Infrared Remote Sensing Data

    NASA Technical Reports Server (NTRS)

    Quattrochi, Dale A.; Goel, Narendra S.

    1995-01-01

    Although remote sensing has a central role to play in the acquisition of synoptic data obtained at multiple spatial and temporal scales to facilitate our understanding of local and regional processes as they influence the global climate, the use of thermal infrared (TIR) remote sensing data in this capacity has received only minimal attention. This results from some fundamental challenges that are associated with employing TIR data collected at different space and time scales, either with the same or different sensing systems, and also from other problems that arise in applying a multiple scaled approach to the measurement of surface temperatures. In this paper, we describe some of the more important problems associated with using TIR remote sensing data obtained at different spatial and temporal scales, examine why these problems appear as impediments to using multiple scaled TIR data, and provide some suggestions for future research activities that may address these problems. We elucidate the fundamental concept of scale as it relates to remote sensing and explore how space and time relationships affect TIR data from a problem-dependency perspective. We also describe how linearity and non-linearity observation versus parameter relationships affect the quantitative analysis of TIR data. Some insight is given on how the atmosphere between target and sensor influences the accurate measurement of surface temperatures and how these effects will be compounded in analyzing multiple scaled TIR data. Last, we describe some of the challenges in modeling TIR data obtained at different space and time scales and discuss how multiple scaled TIR data can be used to provide new and important information for measuring and modeling land-atmosphere energy balance processes.

  5. Spatial Metadata for Global Change Investigations Using Remote Sensing

    NASA Technical Reports Server (NTRS)

    Emerson, Charles W.; Quattrochi, Dale A.; Lam, Nina Siu-Ngan; Arnold, James E. (Technical Monitor)

    2002-01-01

    Satellite and aircraft-borne remote sensors have gathered petabytes of data over the past 30+ years. These images are an important resource for establishing cause and effect relationships between human-induced land cover changes and alterations in climate and other biophysical patterns at local to global scales. However, the spatial, temporal, and spectral characteristics of these datasets vary, thus complicating long-term studies involving several types of imagery. As the geographical and temporal coverage, the spectral and spatial resolution, and the number of individual sensors increase, the sheer volume and complexity of available data sets will complicate management and use of the rapidly growing archive of earth imagery. Mining this vast data resource for images that provide the necessary information for climate change studies becomes more difficult as more sensors are launched and more imagery is obtained.

  6. Integrating remote sensing and spatially explicit epidemiological modeling

    NASA Astrophysics Data System (ADS)

    Finger, Flavio; Knox, Allyn; Bertuzzo, Enrico; Mari, Lorenzo; Bompangue, Didier; Gatto, Marino; Rinaldo, Andrea

    2015-04-01

    Spatially explicit epidemiological models are a crucial tool for the prediction of epidemiological patterns in time and space as well as for the allocation of health care resources. In addition they can provide valuable information about epidemiological processes and allow for the identification of environmental drivers of the disease spread. Most epidemiological models rely on environmental data as inputs. They can either be measured in the field by the means of conventional instruments or using remote sensing techniques to measure suitable proxies of the variables of interest. The later benefit from several advantages over conventional methods, including data availability, which can be an issue especially in developing, and spatial as well as temporal resolution of the data, which is particularly crucial for spatially explicit models. Here we present the case study of a spatially explicit, semi-mechanistic model applied to recurring cholera outbreaks in the Lake Kivu area (Democratic Republic of the Congo). The model describes the cholera incidence in eight health zones on the shore of the lake. Remotely sensed datasets of chlorophyll a concentration in the lake, precipitation and indices of global climate anomalies are used as environmental drivers. Human mobility and its effect on the disease spread is also taken into account. Several model configurations are tested on a data set of reported cases. The best models, accounting for different environmental drivers, and selected using the Akaike information criterion, are formally compared via cross validation. The best performing model accounts for seasonality, El Niño Southern Oscillation, precipitation and human mobility.

  7. Effects of spatially displaced feedback on remote manipulation tasks

    NASA Technical Reports Server (NTRS)

    Manahan, Meera K.; Stuart, Mark A.; Bierschwale, John M.; Hwang, Ellen Y.; Legendre, A. J.

    1992-01-01

    Several studies have been performed to determine the effects on computer and direct manipulation task performance when viewing conditions are spatially displaced. Whether results from these studies can be directly applied to remote manipulation tasks is quenstionable. The objective of this evaluation was to determine the effects of reversed, inverted, and inverted/reversed views on remote manipulation task performance using two 3-Degree of Freedom (DOF) hand controllers and a replica position hand controller. Results showed that trials using the inverted viewing condition showed the worst performance, followed by the inverted/reversed view and the reversed view when using the 2x3 DOF. However, these differences were not significant. The inverted and inverted/reversed viewing conditions were significantly worse than the normal and reversed viewing conditions when using the Kraft Replica. A second evaluation was conducted in which additional trials were performed with each viewing condition to determine the long term effects of spatially displaced views on task performance for the hand controllers. Results of the second evaluation indicated that there was more of a difference in performance between the perturbed viewing conditions and the normal viewing condition with the Kraft Replica than with the 2x3 DOF.

  8. Effective spatial database support for acquiring spatial information from remote sensing images

    NASA Astrophysics Data System (ADS)

    Jin, Peiquan; Wan, Shouhong; Yue, Lihua

    2009-12-01

    In this paper, a new approach to maintain spatial information acquiring from remote-sensing images is presented, which is based on Object-Relational DBMS. According to this approach, the detected and recognized results of targets are stored and able to be further accessed in an ORDBMS-based spatial database system, and users can access the spatial information using the standard SQL interface. This approach is different from the traditional ArcSDE-based method, because the spatial information management module is totally integrated into the DBMS and becomes one of the core modules in the DBMS. We focus on three issues, namely the general framework for the ORDBMS-based spatial database system, the definitions of the add-in spatial data types and operators, and the process to develop a spatial Datablade on Informix. The results show that the ORDBMS-based spatial database support for image-based target detecting and recognition is easy and practical to be implemented.

  9. Observation of own exploration movements impairs haptic spatial perception.

    PubMed

    Mueller, Stephanie; Habermann, Stefanie; Dudda, Janett; Grunwald, Martin

    2013-12-01

    The present study was designed to assess whether the visibility of ones' own exploratory movements impairs or enhances perceptual speed and precision of haptic stimuli with varying complexity. Previous studies have shown that noninformative vision of steady surroundings improves haptic spatial perception. However, due to the serial nature of haptic processing and limited capacity of working memory resources, we hypothesized that noninformative vision of limb movements may impair haptic perception. The study sample consisted of ninety-eight healthy adults who were randomized into two groups, matched for sex and age. Participants were required to explore two-dimensional haptic stimuli with varying complexity and to recognize them visually. The difference between the two experimental groups was a screen that would prevent the participants from viewing their hands during exploration in the nonobservation condition (NonOb). The other half of participants were able to see their hands in the manual movement observation condition (MovOb) thanks to the special design of the stimuli. As hypothesized, the persons in the MovOb condition made significantly more errors. The difference in error frequency between participants of the MovOb and NonOb condition was greater for complex stimuli than for simple ones. These results suggest that incoming visual information about own manual exploration movements increases competitive pressure for limited working memory resources, and therefore, more recognition errors are made. Covering the hands during exploration may constitute a helpful simplification of the task's demands by supporting the maintenance of information in working memory. Additionally, the relation of haptic complexity and stimulus characteristics was analyzed. PMID:24071924

  10. The Impact of Residual Vision in Spatial Skills of Individuals with Visual Impairments

    ERIC Educational Resources Information Center

    Papadopoulos, Konstantinos; Koustriava, Eleni; Kartasidou, Lefkothea

    2011-01-01

    Loss of vision is believed to have a great impact on the acquisition of spatial knowledge. The aims of the present study are to examine the performance of individuals with visual impairments on spatial tasks and the impact of residual vision on processing these tasks. In all, 28 individuals with visual impairments--blindness or low…

  11. Spatial Compression Impairs Prism Adaptation in Healthy Individuals

    PubMed Central

    Scriven, Rachel J.; Newport, Roger

    2013-01-01

    Neglect patients typically present with gross inattention to one side of space following damage to the contralateral hemisphere. While prism-adaptation (PA) is effective in ameliorating some neglect behaviors, the mechanisms involved and their relationship to neglect remain unclear. Recent studies have shown that conscious strategic control (SC) processes in PA may be impaired in neglect patients, who are also reported to show extraordinarily long aftereffects compared to healthy participants. Determining the underlying cause of these effects may be the key to understanding therapeutic benefits. Alternative accounts suggest that reduced SC might result from a failure to detect prism-induced reaching errors properly either because (a) the size of the error is underestimated in compressed visual space or (b) pathologically increased error-detection thresholds reduce the requirement for error correction. The purpose of this study was to model these two alternatives in healthy participants and to examine whether SC and subsequent aftereffects were abnormal compared to standard PA. Each participant completed three PA procedures within a MIRAGE mediated reality environment with direction errors recorded before, during and after adaptation. During PA, visual feedback of the reach could be compressed, perturbed by noise, or represented veridically. Compressed visual space significantly reduced SC and aftereffects compared to control and noise conditions. These results support recent observations in neglect patients, suggesting that a distortion of spatial representation may successfully model neglect and explain neglect performance while adapting to prisms. PMID:23675332

  12. Spatial compression impairs prism adaptation in healthy individuals.

    PubMed

    Scriven, Rachel J; Newport, Roger

    2013-01-01

    Neglect patients typically present with gross inattention to one side of space following damage to the contralateral hemisphere. While prism-adaptation (PA) is effective in ameliorating some neglect behaviors, the mechanisms involved and their relationship to neglect remain unclear. Recent studies have shown that conscious strategic control (SC) processes in PA may be impaired in neglect patients, who are also reported to show extraordinarily long aftereffects compared to healthy participants. Determining the underlying cause of these effects may be the key to understanding therapeutic benefits. Alternative accounts suggest that reduced SC might result from a failure to detect prism-induced reaching errors properly either because (a) the size of the error is underestimated in compressed visual space or (b) pathologically increased error-detection thresholds reduce the requirement for error correction. The purpose of this study was to model these two alternatives in healthy participants and to examine whether SC and subsequent aftereffects were abnormal compared to standard PA. Each participant completed three PA procedures within a MIRAGE mediated reality environment with direction errors recorded before, during and after adaptation. During PA, visual feedback of the reach could be compressed, perturbed by noise, or represented veridically. Compressed visual space significantly reduced SC and aftereffects compared to control and noise conditions. These results support recent observations in neglect patients, suggesting that a distortion of spatial representation may successfully model neglect and explain neglect performance while adapting to prisms. PMID:23675332

  13. Improved effect of Pycnogenol on impaired spatial memory function in partial androgen deficiency rat model.

    PubMed

    Hasegawa, Noboru; Mochizuki, Miyako

    2009-06-01

    The improved effect of Pycnogenol on impaired spatial memory function was studied in orchidectomized rats. Endogenous testosterone levels were decreased by approximately one-half for 3 months after castration. In the radial arm maze, castration significantly impaired working and reference memory function without lowering motor function. Pycnogenol increased the NGF content in the hippocampus and cortex, and improved the spatial memory impairment. These observations confirmed that diagnostic accuracy can be improved by Pycnogenol in androgen-deficient rats. PMID:19142987

  14. Remote sensing of atmospheric greenhouse gases: bridging spatial scales

    NASA Astrophysics Data System (ADS)

    Humpage, N.; Boesch, H.; Parker, R.; Hewson, W.; Sembhi, H.; Somkuti, P.; Webb, A.; Palmer, P. I.; Feng, L.

    2015-12-01

    Observed atmospheric variations of greenhouse gases (GHG) are determined by surface-atmosphere exchange, and atmospheric chemistry and transport. These processes occur over a wide spectrum of spatial and temporal scales. Confronting atmospheric transport models and ultimately improving the fidelity of surface flux estimates demands an integrated observing system that captures these scales. We will discuss using data the role of GHG remote sensing instruments and argue that our ability to deploy them from the ground and to fly them on satellite, aircraft, and unmanned airborne vehicles (UAV) mean that they represent the ideal technology to bridge the observed scales of variability. We will discuss a five-year record of global-scale column observations of CO2 and CH4 from the Japanese GOSAT satellite instrument that is available from University of Leicester as part of the ESA Climate Change Initiative. We will showcase new CO2 and CH4 column data that was collected by our shortwave infrared spectrometer GHOST oboard the NASA Global Hak during a regional survey over the eastern Pacific during early spring 2015, which included coincident overpasses from GOSAT and the NASA OCO-2. These data are being used to test atmospheric transport models over remote regions and to help validate satellite observations over the oceans. We will also discuss GHOST data collected on the UK Dornier 226 research aircraft to measure local-scale measurements over Leicester city centre, a major power plant, and downwind of a controlled Cumbrian heathland fire. Finally, we will report preliminary results from a new ground-based Fourier transform spectrometer station at Harwell (80 km west of London). We anticipate that this site will eventually join the TCCON network, which has been used to validation of satellite observations.

  15. Acute and chronic tramadol administration impair spatial memory in rat

    PubMed Central

    Hosseini-Sharifabad, Ali; Rabbani, Mohammad; Sharifzadeh, Mohammad; Bagheri, Narges

    2016-01-01

    Tramadol hydrochloride, a synthetic opioid, acts via a multiple mechanism of action. Tramadol can potentially change the behavioral phenomena. The present study evaluates the effect of tramadol after single or multiple dose/s on the spatial memory of rat using object recognition task (ORT). Tramadol, 20 mg/kg, was injected intraperitoneally (i.p) as a single dose or once a day for 21 successive days considered as acute or chronic treatment respectively. After treatment, animals underwent two trials in the ORT. In the first trial (T1), animals encountered with two identical objects for exploration in a five-minute period. After 1 h, in the T2 trial, the animals were exposed to a familiar and a nonfamiliar object. The exploration times and frequency of the exploration for any objects were recorded. The results showed that tramadol decreased the exploration times for the nonfamiliar object in the T2 trial when administered either as a single dose (P<0.001) or as the multiple dose (P<0.05) compared to the respective control groups. Both acute and chronic tramadol administration eliminated the different frequency of exploration between the familiar and nonfamiliar objects. Our findings revealed that tramadol impaired memory when administered acutely or chronically. Single dose administration of tramadol showed more destructive effect than multiple doses of tramadol on the memory. The observed data can be explained by the inhibitory effects of tramadol on the wide range of neurotransmitters and receptors including muscarinic, N-methyl D-aspartate, AMPA as well as some second messenger like cAMP and cGMP or its stimulatory effect on the opioid, gama amino butyric acid, dopamine or serotonin in the brain. PMID:27051432

  16. Extraction of spatial information from remotely sensed image data - an example: gloria sidescan sonar images

    USGS Publications Warehouse

    Chavez, Pat S., Jr.; Gardner, James V.

    1994-01-01

    A method to extract spatial amplitude and variability information from remotely sensed digital imaging data is presented. High Pass Filters (HPFs) are used to compute both a Spatial Amplitude Image/Index (SAI) and Spatial Variability Image/Index (SVI) at the local, intermediate, and regional scales. Used as input to principal component analysis and automatic clustering classification, the results indicate that spatial information at scales other than local is useful in the analysis of remotely sensed data. The resultant multi-spatial data set allows the user to study and analyze an image based more on the complete spatial characteristics of an image than only local textural information.

  17. Use of UAS remote sensing data to estimate crop ET at high spatial resolution

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Estimation of the spatial distribution of evapotranspiration (ET) based on remotely sensed imagery has become useful for managing water in irrigated agricultural at various spatial scales. However, data acquired by conventional satellites (Landsat, ASTER, etc.) lack the spatial resolution to capture...

  18. Children with Chromosome 22q11.2 Deletion Syndrome Exhibit Impaired Spatial Working Memory

    ERIC Educational Resources Information Center

    Wong, Ling M.; Riggins, Tracy; Harvey, Danielle; Cabaral, Margarita; Simon, Tony J.

    2014-01-01

    Individuals with chromosome 22q11.2 deletion syndrome (22q11.2DS) have been shown to have impairments in processing spatiotemporal information. The authors examined whether children with 22q11.2DS exhibit impairments in spatial working memory performance due to these weaknesses, even when controlling for maintenance of attention. Children with…

  19. Natural gas leaks detection by spatial-resolvable-CW-laser-based remote monitoring

    SciTech Connect

    Agishev, R.R.; Bajazitov, R.A.; Galeyev, M.M.; Ismagilow, Z.B.

    1996-12-31

    The opportunities of spatial-resolvable atmosphere monitoring and atmospheric pollutions remote chemical analysis based on the CW-laser radiants are investigated. A frequency-responsive processing peculiarities of atmosphere remote sensing signals are described. Application of the mentioned approach for the limited hydrocarbons remote detection and sensing is discussed. The requirements to the CW-LIDAR receiving and radiating systems parameters are formulated. The evaluations of the system sensitivity limit, measurement accuracy and accuracy increase ways are presented.

  20. Developmental dyscalculia is related to visuo-spatial memory and inhibition impairment.

    PubMed

    Szucs, Denes; Devine, Amy; Soltesz, Fruzsina; Nobes, Alison; Gabriel, Florence

    2013-01-01

    Developmental dyscalculia is thought to be a specific impairment of mathematics ability. Currently dominant cognitive neuroscience theories of developmental dyscalculia suggest that it originates from the impairment of the magnitude representation of the human brain, residing in the intraparietal sulcus, or from impaired connections between number symbols and the magnitude representation. However, behavioral research offers several alternative theories for developmental dyscalculia and neuro-imaging also suggests that impairments in developmental dyscalculia may be linked to disruptions of other functions of the intraparietal sulcus than the magnitude representation. Strikingly, the magnitude representation theory has never been explicitly contrasted with a range of alternatives in a systematic fashion. Here we have filled this gap by directly contrasting five alternative theories (magnitude representation, working memory, inhibition, attention and spatial processing) of developmental dyscalculia in 9-10-year-old primary school children. Participants were selected from a pool of 1004 children and took part in 16 tests and nine experiments. The dominant features of developmental dyscalculia are visuo-spatial working memory, visuo-spatial short-term memory and inhibitory function (interference suppression) impairment. We hypothesize that inhibition impairment is related to the disruption of central executive memory function. Potential problems of visuo-spatial processing and attentional function in developmental dyscalculia probably depend on short-term memory/working memory and inhibition impairments. The magnitude representation theory of developmental dyscalculia was not supported. PMID:23890692

  1. MICROINJECTION OF DYNORPHIN INTO THE HIPPOCAMPUS IMPAIRS SPATIAL LEARNING IN RATS

    EPA Science Inventory

    The effect of hippocampal dynorphin administration on learning and memory was examined in spatial and nonspatial tasks. ilateral infusion of dynorphin A(1-8)(DYN; 10 or 20 ug in one ul) into the dorsal hippocampus resulted in dose-related impairment of spatial working memory in a...

  2. STYRENE IMPAIRS SERIAL SPATIAL REVERSAL LEARNING IN RATS

    EPA Science Inventory

    Occupational exposure to styrene monomer has been implicated in the etiology of solvent-induced cognitive dysfunction. o evaluate the effects of styrene exposure on learning, rats were trained on a series of reversals of a spatial discrimination, permitting repeated evaluation of...

  3. Local spatial structure of forest biomass and its consequences for remote sensing of carbon stocks

    NASA Astrophysics Data System (ADS)

    Réjou-Méchain, M.; Muller-Landau, H. C.; Detto, M.; Thomas, S. C.; Le Toan, T.; Saatchi, S. S.; Barreto-Silva, J. S.; Bourg, N. A.; Bunyavejchewin, S.; Butt, N.; Brockelman, W. Y.; Cao, M.; Cárdenas, D.; Chiang, J.-M.; Chuyong, G. B.; Clay, K.; Condit, R.; Dattaraja, H. S.; Davies, S. J.; Duque, A.; Esufali, S.; Ewango, C.; Fernando, R. H. S.; Fletcher, C. D.; Gunatilleke, I. A. U. N.; Hao, Z.; Harms, K. E.; Hart, T. B.; Hérault, B.; Howe, R. W.; Hubbell, S. P.; Johnson, D. J.; Kenfack, D.; Larson, A. J.; Lin, L.; Lin, Y.; Lutz, J. A.; Makana, J.-R.; Malhi, Y.; Marthews, T. R.; McEwan, R. W.; McMahon, S. M.; McShea, W. J.; Muscarella, R.; Nathalang, A.; Noor, N. S. M.; Nytch, C. J.; Oliveira, A. A.; Phillips, R. P.; Pongpattananurak, N.; Punchi-Manage, R.; Salim, R.; Schurman, J.; Sukumar, R.; Suresh, H. S.; Suwanvecho, U.; Thomas, D. W.; Thompson, J.; Uríarte, M.; Valencia, R.; Vicentini, A.; Wolf, A. T.; Yap, S.; Yuan, Z.; Zartman, C. E.; Zimmerman, J. K.; Chave, J.

    2014-04-01

    Advances in forest carbon mapping have the potential to greatly reduce uncertainties in the global carbon budget and to facilitate effective emissions mitigation strategies such as REDD+. Though broad scale mapping is based primarily on remote sensing data, the accuracy of resulting forest carbon stock estimates depends critically on the quality of field measurements and calibration procedures. The mismatch in spatial scales between field inventory plots and larger pixels of current and planned remote sensing products for forest biomass mapping is of particular concern, as it has the potential to introduce errors, especially if forest biomass shows strong local spatial variation. Here, we used 30 large (8-50 ha) globally distributed permanent forest plots to quantify the spatial variability in aboveground biomass (AGB) at spatial grains ranging from 5 to 250 m (0.025-6.25 ha), and we evaluate the implications of this variability for calibrating remote sensing products using simulated remote sensing footprints. We found that the spatial sampling error in AGB is large for standard plot sizes, averaging 46.3% for 0.1 ha subplots and 16.6% for 1 ha subplots. Topographically heterogeneous sites showed positive spatial autocorrelation in AGB at scales of 100 m and above; at smaller scales, most study sites showed negative or nonexistent spatial autocorrelation in AGB. We further show that when field calibration plots are smaller than the remote sensing pixels, the high local spatial variability in AGB leads to a substantial "dilution" bias in calibration parameters, a bias that cannot be removed with current statistical methods. Overall, our results suggest that topography should be explicitly accounted for in future sampling strategies and that much care must be taken in designing calibration schemes if remote sensing of forest carbon is to achieve its promise.

  4. Children with Chromosome 22q11.2 Deletion Syndrome Exhibit Impaired Spatial Working Memory

    PubMed Central

    Wong, Ling M; Riggins, Tracy; Harvey, Danielle; Cabaral, Margarita; Simon, Tony J.

    2014-01-01

    Individuals with chromosome 22q11.2 deletion syndrome (22q11.2DS) have been shown to have impairments in processing spatiotemporal information. We examined whether children with 22q11.2DS exhibit impairments in spatial working memory performance due to these weaknesses, even when controlling for maintenance of attention. Children with 22q11.2DS (n = 47) and typically developing controls (n = 49) ages 6–15 years saw images within a grid and after a delay, then indicated the positions of the images in the correct temporal order. Children with 22q11.2DS made more spatial and temporal errors than controls. Females with 22q11.2DS made more spatial and temporal errors than males. These results extend findings of impaired spatiotemporal processing into the memory domain in 22q11.2DS by documenting their influence on working memory performance. PMID:24679349

  5. Netrin-1 improves spatial memory and synaptic plasticity impairment following global ischemia in the rat.

    PubMed

    Bayat, Mahnaz; Baluchnejadmojarad, Tourandokht; Roghani, Mehrdad; Goshadrou, Fatemeh; Ronaghi, Abdolaziz; Mehdizadeh, Mehdi

    2012-05-01

    Cerebral ischemia, which is the second and most common cause of mortality, affects millions of individuals worldwide. The present study was performed to investigate whether intrahippocampal administration of netrin-1 could improve spatial memory impairment in radial arm maze task and restore long-term potentiation (LTP) in 4-vessel occlusion model of global ischemia. The results showed that intrahippocampal infusion of nerin-1 24 h after ischemia (at both doses of 400 and 800 ng) significantly ameliorated spatial memory impairment and at a dose of 800 ng was capable to improve synaptic dysfunction as observed by recovery of population spike component of basal evoked potential and LTP through enhancement of excitability and normalization of paired pulse response. Taken together, the present study shows that netrin-1 dose-dependently ameliorates spatial memory impairment and improves synaptic dysfunction as observed by recovery of population spike component of basal evoked potential and LTP in rats with global ischemia. PMID:22459051

  6. Isoflurane-Induced Spatial Memory Impairment in Mice is Prevented by the Acetylcholinesterase Inhibitor Donepezil

    PubMed Central

    Wang, Beilei; Xu, Huan; Li, Wen; Chen, Jie; Wang, Xiangrui

    2011-01-01

    Although many studies have shown that isoflurane exposure impairs spatial memory in aged animals, there are no clinical treatments available to prevent this memory deficit. The anticholinergic properties of volatile anesthetics are a biologically plausible cause of cognitive dysfunction in elderly subjects. We hypothesized that pretreatment with the acetylcholinesterase inhibitor donepezil, which has been approved by the Food and Drug Administration (FDA) for the treatment of Alzheimer's disease, prevents isoflurane-induced spatial memory impairment in aged mice. In present study, eighteen-month-old mice were administered donepezil (5 mg/kg) or an equal volume of saline by oral gavage with a feeding needle for four weeks. Then the mice were exposed to isoflurane (1.2%) for six hours. Two weeks later, mice were subjected to the Morris water maze to examine the impairment of spatial memory after exposure to isoflurane. After the behavioral test, the mice were sacrificed, and the protein expression level of acetylcholinesterase (AChE), choline acetylase (ChAT) and α7 nicotinic receptor (α7-nAChR) were measured in the brain. Each group consisted of 12 mice. We found that isoflurane exposure for six hours impaired the spatial memory of the mice. Compared with the control group, isoflurane exposure dramatically decreased the protein level of ChAT, but not AChE or α7-nAChR. Donepezil prevented isoflurane-induced spatial memory impairments and increased ChAT levels, which were downregulated by isoflurane. In conclusions, pretreatment with the AChE inhibitor donepezil prevented isoflurane-induced spatial memory impairment in aged mice. The mechanism was associated with the upregulation of ChAT, which was decreased by isoflurane. PMID:22114680

  7. Isoflurane-induced spatial memory impairment in mice is prevented by the acetylcholinesterase inhibitor donepezil.

    PubMed

    Su, Diansan; Zhao, Yanxing; Wang, Beilei; Xu, Huan; Li, Wen; Chen, Jie; Wang, Xiangrui

    2011-01-01

    Although many studies have shown that isoflurane exposure impairs spatial memory in aged animals, there are no clinical treatments available to prevent this memory deficit. The anticholinergic properties of volatile anesthetics are a biologically plausible cause of cognitive dysfunction in elderly subjects. We hypothesized that pretreatment with the acetylcholinesterase inhibitor donepezil, which has been approved by the Food and Drug Administration (FDA) for the treatment of Alzheimer's disease, prevents isoflurane-induced spatial memory impairment in aged mice. In present study, eighteen-month-old mice were administered donepezil (5 mg/kg) or an equal volume of saline by oral gavage with a feeding needle for four weeks. Then the mice were exposed to isoflurane (1.2%) for six hours. Two weeks later, mice were subjected to the Morris water maze to examine the impairment of spatial memory after exposure to isoflurane. After the behavioral test, the mice were sacrificed, and the protein expression level of acetylcholinesterase (AChE), choline acetylase (ChAT) and α7 nicotinic receptor (α7-nAChR) were measured in the brain. Each group consisted of 12 mice. We found that isoflurane exposure for six hours impaired the spatial memory of the mice. Compared with the control group, isoflurane exposure dramatically decreased the protein level of ChAT, but not AChE or α7-nAChR. Donepezil prevented isoflurane-induced spatial memory impairments and increased ChAT levels, which were downregulated by isoflurane. In conclusions, pretreatment with the AChE inhibitor donepezil prevented isoflurane-induced spatial memory impairment in aged mice. The mechanism was associated with the upregulation of ChAT, which was decreased by isoflurane. PMID:22114680

  8. Hippocampal Volume Reduction in Humans Predicts Impaired Allocentric Spatial Memory in Virtual-Reality Navigation

    PubMed Central

    Dzieciol, Anna M.; Gadian, David G.; Jentschke, Sebastian; Doeller, Christian F.; Burgess, Neil; Mishkin, Mortimer

    2015-01-01

    The extent to which navigational spatial memory depends on hippocampal integrity in humans is not well documented. We investigated allocentric spatial recall using a virtual environment in a group of patients with severe hippocampal damage (SHD), a group of patients with “moderate” hippocampal damage (MHD), and a normal control group. Through four learning blocks with feedback, participants learned the target locations of four different objects in a circular arena. Distal cues were present throughout the experiment to provide orientation. A circular boundary as well as an intra-arena landmark provided spatial reference frames. During a subsequent test phase, recall of all four objects was tested with only the boundary or the landmark being present. Patients with SHD were impaired in both phases of this task. Across groups, performance on both types of spatial recall was highly correlated with memory quotient (MQ), but not with intelligence quotient (IQ), age, or sex. However, both measures of spatial recall separated experimental groups beyond what would be expected based on MQ, a widely used measure of general memory function. Boundary-based and landmark-based spatial recall were both strongly related to bilateral hippocampal volumes, but not to volumes of the thalamus, putamen, pallidum, nucleus accumbens, or caudate nucleus. The results show that boundary-based and landmark-based allocentric spatial recall are similarly impaired in patients with SHD, that both types of recall are impaired beyond that predicted by MQ, and that recall deficits are best explained by a reduction in bilateral hippocampal volumes. SIGNIFICANCE STATEMENT In humans, bilateral hippocampal atrophy can lead to profound impairments in episodic memory. Across species, perhaps the most well-established contribution of the hippocampus to memory is not to episodic memory generally but to allocentric spatial memory. However, the extent to which navigational spatial memory depends on

  9. Local spatial structure of forest biomass and its consequences for remote sensing of carbon stocks

    NASA Astrophysics Data System (ADS)

    Réjou-Méchain, M.; Muller-Landau, H. C.; Detto, M.; Thomas, S. C.; Le Toan, T.; Saatchi, S. S.; Barreto-Silva, J. S.; Bourg, N. A.; Bunyavejchewin, S.; Butt, N.; Brockelman, W. Y.; Cao, M.; Cárdenas, D.; Chiang, J.-M.; Chuyong, G. B.; Clay, K.; Condit, R.; Dattaraja, H. S.; Davies, S. J.; Duque, A.; Esufali, S.; Ewango, C.; Fernando, R. H. S.; Fletcher, C. D.; Gunatilleke, I. A. U. N.; Hao, Z.; Harms, K. E.; Hart, T. B.; Hérault, B.; Howe, R. W.; Hubbell, S. P.; Johnson, D. J.; Kenfack, D.; Larson, A. J.; Lin, L.; Lin, Y.; Lutz, J. A.; Makana, J.-R.; Malhi, Y.; Marthews, T. R.; McEwan, R. W.; McMahon, S. M.; McShea, W. J.; Muscarella, R.; Nathalang, A.; Noor, N. S. M.; Nytch, C. J.; Oliveira, A. A.; Phillips, R. P.; Pongpattananurak, N.; Punchi-Manage, R.; Salim, R.; Schurman, J.; Sukumar, R.; Suresh, H. S.; Suwanvecho, U.; Thomas, D. W.; Thompson, J.; Uríarte, M.; Valencia, R.; Vicentini, A.; Wolf, A. T.; Yap, S.; Yuan, Z.; Zartman, C. E.; Zimmerman, J. K.; Chave, J.

    2014-12-01

    Advances in forest carbon mapping have the potential to greatly reduce uncertainties in the global carbon budget and to facilitate effective emissions mitigation strategies such as REDD+ (Reducing Emissions from Deforestation and Forest Degradation). Though broad-scale mapping is based primarily on remote sensing data, the accuracy of resulting forest carbon stock estimates depends critically on the quality of field measurements and calibration procedures. The mismatch in spatial scales between field inventory plots and larger pixels of current and planned remote sensing products for forest biomass mapping is of particular concern, as it has the potential to introduce errors, especially if forest biomass shows strong local spatial variation. Here, we used 30 large (8-50 ha) globally distributed permanent forest plots to quantify the spatial variability in aboveground biomass density (AGBD in Mg ha-1) at spatial scales ranging from 5 to 250 m (0.025-6.25 ha), and to evaluate the implications of this variability for calibrating remote sensing products using simulated remote sensing footprints. We found that local spatial variability in AGBD is large for standard plot sizes, averaging 46.3% for replicate 0.1 ha subplots within a single large plot, and 16.6% for 1 ha subplots. AGBD showed weak spatial autocorrelation at distances of 20-400 m, with autocorrelation higher in sites with higher topographic variability and statistically significant in half of the sites. We further show that when field calibration plots are smaller than the remote sensing pixels, the high local spatial variability in AGBD leads to a substantial "dilution" bias in calibration parameters, a bias that cannot be removed with standard statistical methods. Our results suggest that topography should be explicitly accounted for in future sampling strategies and that much care must be taken in designing calibration schemes if remote sensing of forest carbon is to achieve its promise.

  10. Comprehension of Spatial Language in Williams Syndrome: Evidence for Impaired Spatial Representation of Verbal Descriptions

    ERIC Educational Resources Information Center

    Laing, Emma; Jarrold, Christopher

    2007-01-01

    Individuals with the rare genetic disorder, Williams syndrome, have an unusual cognitive profile with relatively good language abilities but poor non-verbal and spatial skills. This study explored the interaction between linguistic and spatial functioning in Williams syndrome by investigating individuals' comprehension of spatial language. A group…

  11. Spatial scale of chlorophyll-a concentration in Lake Taihu by using remote sensing images

    NASA Astrophysics Data System (ADS)

    Bao, Ying; Tian, Qingjiu

    2010-09-01

    Chlorophyll-a concentration is one of the most important indexes of Lake Eutrophication. Fine temporal and spatial resolution remote sensing images provide an effective way to monitor blue-green algae in Lake Taihu by studying the spatial distribution regularities of chla concentration. However, both low spatial resolution remote sensing images (e.g. MODIS) due to their heterogeneity and high or moderate spatial resolution remote sensing images (e.g. TM/ETM+) due to their low temporal resolution give rise to unsatisfactory estimate of chla concentration. Therefore, in this study, an effective method for estimating chla concentration using remote sensing images at different scales was developed. Chla concentration was inferred from Hyperion images at 30m resolution and MODIS images at 250m resolution. The spatial variability of Chla concentration was analyzed and Taihu Lake was divided into area with low variability and area with high variability. The quadratic polynomial (R2=0.8709) and linear (R2=0.7387) correlation was established. Finally, the obtained relationship between chla concentration estimate at different spatial scales were applied to correct the estimate from MODIS data.

  12. Remote sensing inputs to landscape models which predict future spatial land use patterns for hydrologic models

    NASA Technical Reports Server (NTRS)

    Miller, L. D.; Tom, C.; Nualchawee, K.

    1977-01-01

    A tropical forest area of Northern Thailand provided a test case of the application of the approach in more natural surroundings. Remote sensing imagery subjected to proper computer analysis has been shown to be a very useful means of collecting spatial data for the science of hydrology. Remote sensing products provide direct input to hydrologic models and practical data bases for planning large and small-scale hydrologic developments. Combining the available remote sensing imagery together with available map information in the landscape model provides a basis for substantial improvements in these applications.

  13. Agricultural practices in grasslands detected by spatial remote sensing.

    PubMed

    Dusseux, Pauline; Vertès, Françoise; Corpetti, Thomas; Corgne, Samuel; Hubert-Moy, Laurence

    2014-12-01

    The major decrease in grassland surfaces associated with changes in their management that has been observed in many regions of the earth during the last half century has major impacts on environmental and socio-economic systems. This study focuses on the identification of grassland management practices in an intensive agricultural watershed located in Brittany, France, by analyzing the intra-annual dynamics of the surface condition of vegetation using remotely sensed and field data. We studied the relationship between one vegetation index (NDVI) and two biophysical variables (LAI and fCOVER) derived from a series of three SPOT images on one hand and measurements collected during field campaigns achieved on 120 grasslands on the other. The results show that the LAI appears as the best predictor for monitoring grassland mowing and grazing. Indeed, because of its ability to characterize vegetation status, LAI estimated from remote sensing data is a relevant variable to identify these practices. LAI values derived from the SPOT images were then classified based on the K-Nearest Neighbor (KNN) supervised algorithm. The results points out that the distribution of grassland management practices such as grazing and mowing can be mapped very accurately (Kappa index = 0.82) at a field scale over large agricultural areas using a series of satellite images. PMID:25182683

  14. Histone Acetylation Regulation in Sleep Deprivation-Induced Spatial Memory Impairment.

    PubMed

    Duan, Ruifeng; Liu, Xiaohua; Wang, Tianhui; Wu, Lei; Gao, Xiujie; Zhang, Zhiqing

    2016-09-01

    Sleep disorders negatively affect cognition and health. Recent evidence has indicated that chromatin remodeling via histone acetylation regulates cognitive function. This study aimed to investigate the possible roles of histone acetylation in sleep deprivation (SD)-induced cognitive impairment. Results of the Morris water maze test showed that 3 days of SD can cause spatial memory impairment in Wistar rats. SD can also decrease histone acetylation levels, increase histone deacetylase 2 (HDAC2) expression, and decrease histone acetyltransferase (CBP) expression. Furthermore, SD can reduce H3 and H4 acetylation levels in the promoters of the brain-derived neurotrophic factor (Bdnf) gene and thus significantly downregulate BDNF expression and impair the activity of key BDNF signaling pathways (pCaMKII, pErk2, and pCREB). However, treatment with the HDAC inhibitor trichostatin A attenuated all the negative effects induced by SD. Therefore, BDNF and its histone acetylation regulation may play important roles in SD-induced spatial memory impairment, whereas HDAC inhibition possibly confers protection against SD-induced impairment in spatial memory and hippocampal functions. PMID:27161370

  15. SPATIAL VARIABILITY OF REMOTELY SENSED SURFACE TEMPERATURE AT FIELD SCALE

    EPA Science Inventory

    Bare soil surface temperatures (BST) and crop canopy temperatures (CCT) were collected from a 1-ha field in central Arizona using an infrared thermometer to determine whether they were spatially correlated. The measurements were taken from a two-dimensional random sampling patter...

  16. Extensive Lesions of Cholinergic Basal Forebrain Neurons Do Not Impair Spatial Working Memory

    ERIC Educational Resources Information Center

    Vuckovich, Joseph A.; Semel, Mara E.; Baxter, Mark G.

    2004-01-01

    A recent study suggests that lesions to all major areas of the cholinergic basal forebrain in the rat (medial septum, horizontal limb of the diagonal band of Broca, and nucleus basalis magnocellularis) impair a spatial working memory task. However, this experiment used a surgical technique that may have damaged cerebellar Purkinje cells. The…

  17. Predicting Efficiency of Travel in Young, Visually Impaired Children from Their Other Spatial Skills.

    ERIC Educational Resources Information Center

    Hill, Anita; And Others

    1985-01-01

    To test ways of predicting how efficiently visually impaired children learn travel skills, a criteria checklist of spatial skills was developed for close-body space, local space, and geographical/travel space. Comparison was made between predictors of efficient learning including subjective ratings of teachers, personal qualities and factors of…

  18. The Use of Spatialized Speech in Auditory Interfaces for Computer Users Who Are Visually Impaired

    ERIC Educational Resources Information Center

    Sodnik, Jaka; Jakus, Grega; Tomazic, Saso

    2012-01-01

    Introduction: This article reports on a study that explored the benefits and drawbacks of using spatially positioned synthesized speech in auditory interfaces for computer users who are visually impaired (that is, are blind or have low vision). The study was a practical application of such systems--an enhanced word processing application compared…

  19. Spatial but Not Object Memory Impairments in Children with Fetal Alcohol Syndrome.

    ERIC Educational Resources Information Center

    Nadel, Lynn; Uecker, Anne

    1998-01-01

    Thirty Native American children (mean age=10.3 years), 15 identified with fetal alcohol syndrome (FAS) and 15 controls, were asked to recall places and objects in a task previously shown to be sensitive to memory skills in individuals with and without mental retardation. Children with FAS demonstrated a spatial but not an object memory impairment.…

  20. Spatial estimation from remotely sensed data via empirical Bayes models

    NASA Technical Reports Server (NTRS)

    Hill, J. R.; Hinkley, D. V.; Kostal, H.; Morris, C. N.

    1984-01-01

    Multichannel satellite image data, available as LANDSAT imagery, are recorded as a multivariate time series (four channels, multiple passovers) in two spatial dimensions. The application of parametric empirical Bayes theory to classification of, and estimating the probability of, each crop type at each of a large number of pixels is considered. This theory involves both the probability distribution of imagery data, conditional on crop types, and the prior spatial distribution of crop types. For the latter Markov models indexed by estimable parameters are used. A broad outline of the general theory reveals several questions for further research. Some detailed results are given for the special case of two crop types when only a line transect is analyzed. Finally, the estimation of an underlying continuous process on the lattice is discussed which would be applicable to such quantities as crop yield.

  1. Spatial and spectral resolution necessary for remotely sensed vegetation studies

    NASA Technical Reports Server (NTRS)

    Rock, B. N.

    1982-01-01

    An outline is presented of the required spatial and spectral resolution needed for accurate vegetation discrimination and mapping studies as well as for determination of state of health (i.e., detection of stress symptoms) of actively growing vegetation. Good success was achieved in vegetation discrimination and mapping of a heterogeneous forest cover in the ridge and valley portion of the Appalachians using multispectral data acquired with a spatial resolution of 15 m (IFOV). A sensor system delivering 10 to 15 m spatial resolution is needed for both vegetation mapping and detection of stress symptoms. Based on the vegetation discrimination and mapping exercises conducted at the Lost River site, accurate products (vegetation maps) are produced using broad-band spectral data ranging from the .500 to 2.500 micron portion of the spectrum. In order of decreasing utility for vegetation discrimination, the four most valuable TM simulator VNIR bands are: 6 (1.55 to 1.75 microns), 3 (0.63 to 0.69 microns), 5 (1.00 to 1.30 microns) and 4 (0.76 to 0.90 microns).

  2. Challenges of Remote Sensing and Spatial Information Education and Technology Transfer in a Fast Developing Industry

    NASA Astrophysics Data System (ADS)

    Tsai, F.; Chen, L.-C.

    2014-04-01

    During the past decade, Taiwan has experienced an unusual and fast growing in the industry of mapping, remote sensing, spatial information and related markets. A successful space program and dozens of advanced airborne and ground-based remote sensing instruments as well as mobile mapping systems have been implemented and put into operation to support the vast demands of geospatial data acquisition. Moreover, in addition to the government agencies and research institutes, there are also tens of companies in the private sector providing geo-spatial data and services. However, the fast developing industry is also posing a great challenge to the education sector in Taiwan, especially the higher education for geo-spatial information. Facing this fast developing industry, the demands of skilled professionals and new technologies in order to address diversified needs are indubitably high. Consequently, while delighting in the expanding and prospering benefitted from the fast growing industry, how to fulfill these demands has become a challenge for the remote sensing and spatial information disciplines in the higher education institutes in Taiwan. This paper provides a brief insight into the status of the remote sensing and spatial information industry in Taiwan as well as the challenges of the education and technology transfer to support the increasing demands and to ensure the continuous development of the industry. In addition to the report of the current status of the remote sensing and spatial information related courses and programs in the colleges and universities, current and potential threatening issues and possible resolutions are also discussed in different points of view.

  3. Spatial predictions of cover attributes of rangeland ecosystems using regression kriging and remote sensing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sound rangeland management requires accurate information on rangeland condition over large landscapes. A commonly-applied approach to making spatial predictions of attributes related to rangeland condition (e.g., shrub or bare ground cover) from remote sensing is via regression between field and rem...

  4. Geographic information systems, remote sensing, and spatial analysis activities in Texas, 2002-07

    USGS Publications Warehouse

    Pearson, D.K.; Gary, R.H.; Wilson, Z.D.

    2007-01-01

    Geographic information system (GIS) technology has become an important tool for scientific investigation, resource management, and environmental planning. A GIS is a computer-aided system capable of collecting, storing, analyzing, and displaying spatially referenced digital data. GIS technology is particularly useful when analyzing a wide variety of spatial data such as with remote sensing and spatial analysis. Remote sensing involves collecting remotely sensed data, such as satellite imagery, aerial photography, or radar images, and analyzing the data to gather information or investigate trends about the environment or the Earth's surface. Spatial analysis combines remotely sensed, thematic, statistical, quantitative, and geographical data through overlay, modeling, and other analytical techniques to investigate specific research questions. It is the combination of data formats and analysis techniques that has made GIS an essential tool in scientific investigations. This document presents information about the technical capabilities and project activities of the U.S. Geological Survey (USGS) Texas Water Science Center (TWSC) GIS Workgroup from 2002 through 2007.

  5. Geographic Information Systems, Remote Sensing, and Spatial Analysis Activities in Texas, 2002-07

    USGS Publications Warehouse

    Pearson, D.K.; Gary, R.H.; Wilson, Z.D.

    2007-01-01

    Geographic information system (GIS) technology has become an important tool for scientific investigation, resource management, and environmental planning. A GIS is a computer-aided system capable of collecting, storing, analyzing, and displaying spatially referenced digital data. GIS technology is particularly useful when analyzing a wide variety of spatial data such as with remote sensing and spatial analysis. Remote sensing involves collecting remotely sensed data, such as satellite imagery, aerial photography, or radar images, and analyzing the data to gather information or investigate trends about the environment or the Earth's surface. Spatial analysis combines remotely sensed, thematic, statistical, quantitative, and geographical data through overlay, modeling, and other analytical techniques to investigate specific research questions. It is the combination of data formats and analysis techniques that has made GIS an essential tool in scientific investigations. This document presents information about the technical capabilities and project activities of the U.S. Geological Survey (USGS) Texas Water Science Center (TWSC) GIS Workgroup from 2002 through 2007.

  6. Conditional forebrain deletion of the L-type calcium channel Ca V 1.2 disrupts remote spatial memories in mice.

    PubMed

    White, Jessica A; McKinney, Brandon C; John, Manorama C; Powers, Patricia A; Kamp, Timothy J; Murphy, Geoffrey G

    2008-01-01

    To determine whether L-type voltage-gated calcium channels (L-VGCCs) are required for remote memory consolidation, we generated conditional knockout mice in which the L-VGCC isoform Ca(V)1.2 was postnatally deleted in the hippocampus and cortex. In the Morris water maze, both Ca(V)1.2 conditional knockout mice (Ca(V)1.2(cKO)) and control littermates displayed a marked decrease in escape latencies and performed equally well on probe trials administered during training. In distinct contrast to their performance during training, Ca(V)1.2(cKO) mice exhibited significant impairments in spatial memory when examined 30 d after training, suggesting that Ca(V)1.2 plays a critical role in consolidation of remote spatial memories. PMID:18174367

  7. Deletion of PEA-15 in mice is associated with specific impairments of spatial learning abilities

    PubMed Central

    2009-01-01

    Background PEA-15 is a phosphoprotein that binds and regulates ERK MAP kinase and RSK2 and is highly expressed throughout the brain. PEA-15 alters c-Fos and CREB-mediated transcription as a result of these interactions. To determine if PEA-15 contributes to the function of the nervous system we tested mice lacking PEA-15 in a series of experiments designed to measure learning, sensory/motor function, and stress reactivity. Results We report that PEA-15 null mice exhibited impaired learning in three distinct spatial tasks, while they exhibited normal fear conditioning, passive avoidance, egocentric navigation, and odor discrimination. PEA-15 null mice also had deficient forepaw strength and in limited instances, heightened stress reactivity and/or anxiety. However, these non-cognitive variables did not appear to account for the observed spatial learning impairments. The null mice maintained normal weight, pain sensitivity, and coordination when compared to wild type controls. Conclusion We found that PEA-15 null mice have spatial learning disabilities that are similar to those of mice where ERK or RSK2 function is impaired. We suggest PEA-15 may be an essential regulator of ERK-dependent spatial learning. PMID:19917132

  8. Reentrainment Impairs Spatial Working Memory until Both Activity Onset and Offset Reentrain.

    PubMed

    Ruby, Norman F; Patton, Danica F; Bane, Shalmali; Looi, David; Heller, H Craig

    2015-10-01

    Compression of the active phase (α) during reentrainment to phase-shifted light-dark (LD) cycles is a common feature of circadian systems, but its functional consequences have not been investigated. This study tested whether α compression in Siberian hamsters (Phodopus sungorus) impaired their spatial working memory as assessed by spontaneous alternation (SA) behavior in a T-maze. Animals were exposed to a 1- or 3-h phase delay of the LD cycle (16 h light/8 h dark). SA behavior was tested at 4 multiday intervals after the phase shift, and α was quantified for those days. All animals failed at the SA task while α was decompressing but recovered spatial memory ability once α returned to baseline levels. A second experiment exposed hamsters to a 2-h light pulse either early or late at night to compress α without phase-shifting the LD cycle. SA behavior was impaired until α decompressed to baseline levels. In a third experiment, α was compressed by changing photoperiod (LD 16:8, 18:6, 20:4) to see if absolute differences in α were related to spatial memory ability. Animals performed the SA task successfully in all 3 photoperiods. These data show that the dynamic process of α compression and decompression impairs spatial working memory and suggests that α modulation is a potential biomarker for assessing the impact of transmeridian flight or shift work on memory. PMID:26224657

  9. Spatial heterogeneity of leaf area index across scales from simulation and remote sensing

    NASA Astrophysics Data System (ADS)

    Reichenau, Tim G.; Korres, Wolfgang; Montzka, Carsten; Schneider, Karl

    2016-04-01

    Leaf area index (LAI, single sided leaf area per ground area) influences mass and energy exchange of vegetated surfaces. Therefore LAI is an input variable for many land surface schemes of coupled large scale models, which do not simulate LAI. Since these models typically run on rather coarse resolution grids, LAI is often inferred from coarse resolution remote sensing. However, especially in agriculturally used areas, a grid cell of these products often covers more than a single land-use. In that case, the given LAI does not apply to any single land-use. Therefore, the overall spatial heterogeneity in these datasets differs from that on resolutions high enough to distinguish areas with differing land-use. Detailed process-based plant growth models simulate LAI for separate plant functional types or specific species. However, limited availability of observations causes reduced spatial heterogeneity of model input data (soil, weather, land-use). Since LAI is strongly heterogeneous in space and time and since processes depend on LAI in a nonlinear way, a correct representation of LAI spatial heterogeneity is also desirable on coarse resolutions. The current study assesses this issue by comparing the spatial heterogeneity of LAI from remote sensing (RapidEye) and process-based simulations (DANUBIA simulation system) across scales. Spatial heterogeneity is assessed by analyzing LAI frequency distributions (spatial variability) and semivariograms (spatial structure). Test case is the arable land in the fertile loess plain of the Rur catchment near the Germany-Netherlands border.

  10. Visual neglect: is there a relationship between impaired spatial working memory and re-cancellation?

    PubMed

    Wansard, Murielle; Meulemans, Thierry; Gillet, Sophie; Segovia, Fermin; Bastin, Christine; Toba, Monica N; Bartolomeo, Paolo

    2014-10-01

    In visual search tasks, neglect patients tend to explore and repeatedly re-cancel stimuli on the ipsilesional side, as if they did not realize that they had previously examined the rightward locations favoured by their lateral bias. The aim of this study was to explore the hypothesis that a spatial working memory deficit explains these ipsilesional re-cancellation errors in neglect patients. For the first time, we evaluated spatial working memory and re-cancellation through separate and independent tasks in a group of patients with right hemisphere damage and a diagnosis of left neglect. Results showed impaired spatial working memory in neglect patients. Compared to the control group, neglect patients cancelled fewer targets and made more re-cancellations both on the left side and on the right side. The spatial working memory deficit appears to be related to re-cancellations, but only for some neglect patients. Alternative interpretations of re-exploration of space are discussed. PMID:24989636

  11. Urban expansion analysis based on spatial variables derived from multi-temporal remote sensing imagery

    NASA Astrophysics Data System (ADS)

    Yang, Yetao; Wang, Yingying; Zhou, Qiming; Gong, Jianya

    2008-10-01

    In this research, we focus on the spatial pattern of the urban expansion. The spatial pattern of the urban area can be quantitatively delineated by many spatial variables. Numerous spatial variables have been examined to evaluate their applicability to the urban change. These metrics include road network accessibility, built-up density and some landscape metrics. Remote sensing technology was used for monitoring dynamic urban change. Multi-temporal Landsat TM images (1988, 1991, 1994, 1997, 2000, and 2002) were used for the change detection using post-classification comparison method. The road network and its change were extracted from multitemporal images using the GDPA algorithm. Contagion, one of the landscape metrics, was selected, because it it can describe the heterogeneity of the suburban area, where the landuse change is most likely to happen. Analysis has also been conducted to identify the relationship between urban change and these spatial variables.

  12. Long-Term Heavy Ketamine Use is Associated with Spatial Memory Impairment and Altered Hippocampal Activation

    PubMed Central

    Morgan, Celia J. A.; Dodds, Chris M.; Furby, Hannah; Pepper, Fiona; Fam, Johnson; Freeman, Tom P.; Hughes, Emer; Doeller, Christian; King, John; Howes, Oliver; Stone, James M.

    2014-01-01

    Ketamine, a non-competitive N-methyl-d-aspartate receptor antagonist, is rising in popularity as a drug of abuse. Preliminary evidence suggests that chronic, heavy ketamine use may have profound effects on spatial memory but the mechanism of these deficits is as yet unclear. This study aimed to examine the neural mechanism by which heavy ketamine use impairs spatial memory processing. In a sample of 11 frequent ketamine users and 15 poly-drug controls, matched for IQ, age, years in education. We used fMRI utilizing an ROI approach to examine the neural activity of three regions known to support successful navigation; the hippocampus, parahippocampal gyrus, and the caudate nucleus during a virtual reality task of spatial memory. Frequent ketamine users displayed spatial memory deficits, accompanied by and related to, reduced activation in both the right hippocampus and left parahippocampal gyrus during navigation from memory, and in the left caudate during memory updating, compared to controls. Ketamine users also exhibited schizotypal and dissociative symptoms that were related to hippocampal activation. Impairments in spatial memory observed in ketamine users are related to changes in medial temporal lobe activation. Disrupted medial temporal lobe function may be a consequence of chronic ketamine abuse and may relate to schizophrenia-like symptomatology observed in ketamine users. PMID:25538631

  13. Select Overexpression of Homer1a in Dorsal Hippocampus Impairs Spatial Working Memory

    PubMed Central

    Celikel, Tansu; Zivkovic, Aleksandar; Resnik, Evgeny; Hasan, Mazahir T.; Licznerski, Pawel; Osten, Pavel; Rozov, Andrej; Seeburg, Peter H.; Schwarz, Martin K.

    2007-01-01

    Long Homer proteins forge assemblies of signaling components involved in glutamate receptor signaling in postsynaptic excitatory neurons, including those underlying synaptic transmission and plasticity. The short immediate-early gene (IEG) Homer1a can dynamically uncouple these physical associations by functional competition with long Homer isoforms. To examine the consequences of Homer1a-mediated “uncoupling” for synaptic plasticity and behavior, we generated forebrain-specific tetracycline (tet) controlled expression of Venus-tagged Homer1a (H1aV) in mice. We report that sustained overexpression of H1aV impaired spatial working but not reference memory. Most notably, a similar impairment was observed when H1aV expression was restricted to the dorsal hippocampus (HP), which identifies this structure as the principal cortical area for spatial working memory. Interestingly, H1aV overexpression also abolished maintenance of CA3-CA1 long-term potentiation (LTP). These impairments, generated by sustained high Homer1a levels, identify a requirement for long Homer forms in synaptic plasticity and temporal encoding of spatial memory. PMID:18982121

  14. The Effects of Spatial Resolution on the Maize acreage estimation by Remote Sensing

    NASA Astrophysics Data System (ADS)

    Huanxue, Zhang; Qiangzi, Li; Miao, Zhang

    2014-03-01

    Crop acreage estimation is essential to forecast crop production using remote sensing. The different spatial resolution of remotely sensed data directly affects the accuracy of crop acreage estimation. It is necessary and valuable to study the effect of resolution on crop acreage estimation, from both qualitative and quantitative points of view. Therefore, this paper analysed the resolution effect on the accuracy of acreage estimation by using CBERS-02B imagery. Spatial statistics methods and manifold accuracy evaluation indices were used respectively to analyse the data with different spatial resolutions and crop proportion statistics. The study results indicate that decreased spatial resolution will lead to reduced regional accuracy in addition to increased standard deviation, RMSE and bias due to the augmentation of mixed pixels. A replacement of higher resolution data by lower resolution data will have an important impact on the derived crop proportions. The regional accuracy of crop statistics can remain higher than 88%, when the crop proportion is higher than 40%. In summary, the higher resolution of the imagery can lead to increased average regional accuracy. The results of this paper also provide academic and experimental reference to resolve the problem of data selection in crop acreage estimation by remote sensing.

  15. a Data Field Method for Urban Remotely Sensed Imagery Classification Considering Spatial Correlation

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Qin, K.; Zeng, C.; Zhang, E. B.; Yue, M. X.; Tong, X.

    2016-06-01

    Spatial correlation between pixels is important information for remotely sensed imagery classification. Data field method and spatial autocorrelation statistics have been utilized to describe and model spatial information of local pixels. The original data field method can represent the spatial interactions of neighbourhood pixels effectively. However, its focus on measuring the grey level change between the central pixel and the neighbourhood pixels results in exaggerating the contribution of the central pixel to the whole local window. Besides, Geary's C has also been proven to well characterise and qualify the spatial correlation between each pixel and its neighbourhood pixels. But the extracted object is badly delineated with the distracting salt-and-pepper effect of isolated misclassified pixels. To correct this defect, we introduce the data field method for filtering and noise limitation. Moreover, the original data field method is enhanced by considering each pixel in the window as the central pixel to compute statistical characteristics between it and its neighbourhood pixels. The last step employs a support vector machine (SVM) for the classification of multi-features (e.g. the spectral feature and spatial correlation feature). In order to validate the effectiveness of the developed method, experiments are conducted on different remotely sensed images containing multiple complex object classes inside. The results show that the developed method outperforms the traditional method in terms of classification accuracies.

  16. Use of Spatial Variance Information From Remote Sensing Imagery to Map Vegetation Foliage Density

    NASA Astrophysics Data System (ADS)

    Walthall, C. L.; Timlin, D.; Pachepsky, Y.; Dulaney, W.; Daughtry, C.

    2002-12-01

    Maps of foliage density expressed as leaf area index (LAI) are used for natural resources inventories, land surface-atmosphere interaction modeling, and hydrologic modeling. Remote sensing imagery can be used to produce these maps by relating spectral vegetation indexes (SVIs) to LAI calibration samples acquired at selected locations on the surface. This approach traditionally uses ordinary least squares (OLS) relationships between the surface measurements and the SVIs, and does not fully take advantage of the spatial information content of the imagery. Spatial information inherent in a semivariogram of the imagery may provide additional information for mapping LAI patterns. This is demonstrated using a spatially dense sample of corn LAI and calibrated airborne imagery. An LAI map is produced by interpolating surface measurements with a semivariogram from the imagery. The resulting LAI map captures the main spatial features of a LAI map produced by interpolating the surface LAI data with its semivariogram. The image semivariogram approach also provides a product that has less noise characteristic of OLS-based remote sensing methods. The use of the image semivariogram with the surface LAI calibration samples suggests that the spatial domain information can complement spectral information for improving LAI maps especially at high spatial resolution where OLS methods may not perform well.

  17. Gender dimorphism in aspartame-induced impairment of spatial cognition and insulin sensitivity.

    PubMed

    Collison, Kate S; Makhoul, Nadine J; Zaidi, Marya Z; Saleh, Soad M; Andres, Bernard; Inglis, Angela; Al-Rabiah, Rana; Al-Mohanna, Futwan A

    2012-01-01

    Previous studies have linked aspartame consumption to impaired retention of learned behavior in rodents. Prenatal exposure to aspartame has also been shown to impair odor-associative learning in guinea pigs; and recently, aspartame-fed hyperlipidemic zebrafish exhibited weight gain, hyperglycemia and acute swimming defects. We therefore investigated the effects of chronic lifetime exposure to aspartame, commencing in utero, on changes in blood glucose parameters, spatial learning and memory in C57BL/6J mice. Morris Water Maze (MWM) testing was used to assess learning and memory, and a random-fed insulin tolerance test was performed to assess glucose homeostasis. Pearson correlation analysis was used to investigate the associations between body characteristics and MWM performance outcome variables. At 17 weeks of age, male aspartame-fed mice exhibited weight gain, elevated fasting glucose levels and decreased insulin sensitivity compared to controls (P<0.05). Females were less affected, but had significantly raised fasting glucose levels. During spatial learning trials in the MWM (acquisition training), the escape latencies of male aspartame-fed mice were consistently higher than controls, indicative of learning impairment. Thigmotactic behavior and time spent floating directionless was increased in aspartame mice, who also spent less time searching in the target quadrant of the maze (P<0.05). Spatial learning of female aspartame-fed mice was not significantly different from controls. Reference memory during a probe test was affected in both genders, with the aspartame-fed mice spending significantly less time searching for the former location of the platform. Interestingly, the extent of visceral fat deposition correlated positively with non-spatial search strategies such as floating and thigmotaxis, and negatively with time spent in the target quadrant and swimming across the location of the escape platform. These data suggest that lifetime exposure to aspartame

  18. Gender Dimorphism in Aspartame-Induced Impairment of Spatial Cognition and Insulin Sensitivity

    PubMed Central

    Collison, Kate S.; Makhoul, Nadine J.; Zaidi, Marya Z.; Saleh, Soad M.; Andres, Bernard; Inglis, Angela; Al-Rabiah, Rana; Al-Mohanna, Futwan A.

    2012-01-01

    Previous studies have linked aspartame consumption to impaired retention of learned behavior in rodents. Prenatal exposure to aspartame has also been shown to impair odor-associative learning in guinea pigs; and recently, aspartame-fed hyperlipidemic zebrafish exhibited weight gain, hyperglycemia and acute swimming defects. We therefore investigated the effects of chronic lifetime exposure to aspartame, commencing in utero, on changes in blood glucose parameters, spatial learning and memory in C57BL/6J mice. Morris Water Maze (MWM) testing was used to assess learning and memory, and a random-fed insulin tolerance test was performed to assess glucose homeostasis. Pearson correlation analysis was used to investigate the associations between body characteristics and MWM performance outcome variables. At 17 weeks of age, male aspartame-fed mice exhibited weight gain, elevated fasting glucose levels and decreased insulin sensitivity compared to controls (P<0.05). Females were less affected, but had significantly raised fasting glucose levels. During spatial learning trials in the MWM (acquisition training), the escape latencies of male aspartame-fed mice were consistently higher than controls, indicative of learning impairment. Thigmotactic behavior and time spent floating directionless was increased in aspartame mice, who also spent less time searching in the target quadrant of the maze (P<0.05). Spatial learning of female aspartame-fed mice was not significantly different from controls. Reference memory during a probe test was affected in both genders, with the aspartame-fed mice spending significantly less time searching for the former location of the platform. Interestingly, the extent of visceral fat deposition correlated positively with non-spatial search strategies such as floating and thigmotaxis, and negatively with time spent in the target quadrant and swimming across the location of the escape platform. These data suggest that lifetime exposure to aspartame

  19. Patterns of preserved and impaired spatial memory in a case of developmental amnesia

    PubMed Central

    Rosenbaum, R. Shayna; Cassidy, Benjamin N.; Herdman, Katherine A.

    2015-01-01

    The hippocampus is believed to have evolved to support allocentric spatial representations of environments as well as the details of personal episodes that occur within them, whereas other brain structures are believed to support complementary egocentric spatial representations. Studies of patients with adult-onset lesions lend support to these distinctions for newly encountered places but suggest that with time and/or experience, schematic aspects of environments can exist independent of the hippocampus. Less clear is the quality of spatial memories acquired in individuals with impaired episodic memory in the context of a hippocampal system that did not develop normally. Here we describe a detailed investigation of the integrity of spatial representations of environments navigated repeatedly over many years in the rare case of H.C., a person with congenital absence of the mammillary bodies and abnormal hippocampal and fornix development. H.C. and controls who had extensive experience navigating the residential and downtown areas known to H.C. were tested on mental navigation tasks that assess the identity, location, and spatial relations among landmarks, and the ability to represent routes. H.C. was able to represent distances and directions between familiar landmarks and provide accurate, though inefficient, route descriptions. However, difficulties producing detailed spatial features on maps and accurately ordering more than two landmarks that are in close proximity to one another along a route suggest a spatial representation that includes only coarse, schematic information that lacks coherence and that cannot be used flexibly. This pattern of performance is considered in the context of other areas of preservation and impairment exhibited by H.C. and suggests that the allocentric-egocentric dichotomy with respect to hippocampal and extended hippocampal system function may need to be reconsidered. PMID:26029074

  20. Remote Sensing of Vegetation Nitrogen Content for Spatially Explicit Carbon and Water Cycle Estimation

    NASA Astrophysics Data System (ADS)

    Zhang, Y. L.; Miller, J. R.; Chen, J. M.

    2009-05-01

    Foliage nitrogen concentration is a determinant of photosynthetic capacity of leaves, thereby an important input to ecological models for estimating terrestrial carbon and water budgets. Recently, spectrally continuous airborne hyperspectral remote sensing imagery has proven to be useful for retrieving an important related parameter, total chlorophyll content at both leaf and canopy scales. Thus remote sensing of vegetation biochemical parameters has promising potential for improving the prediction of global carbon and water balance patterns. In this research, we explored the feasibility of estimating leaf nitrogen content using hyperspectral remote sensing data for spatially explicit estimation of carbon and water budgets. Multi-year measurements of leaf biochemical contents of seven major boreal forest species were carried out in northeastern Ontario, Canada. The variation of leaf chlorophyll and nitrogen content in response to various growth conditions, and the relationship between them,were investigated. Despite differences in plant type (deciduous and evergreen), leaf age, stand growth conditions and developmental stages, leaf nitrogen content was strongly correlated with leaf chlorophyll content on a mass basis during the active growing season (r2=0.78). With this general correlation, leaf nitrogen content was estimated from leaf chlorophyll content at an accuracy of RMSE=2.2 mg/g, equivalent to 20.5% of the average measured leaf nitrogen content. Based on this correlation and a hyperspectral remote sensing algorithm for leaf chlorophyll content retrieval, the spatial variation of leaf nitrogen content was inferred from the airborne hyperspectral remote sensing imagery acquired by Compact Airborne Spectrographic Imager (CASI). A process-based ecological model Boreal Ecosystem Productivity Simulator (BEPS) was used for estimating terrestrial carbon and water budgets. In contrast to the scenario with leaf nitrogen content assigned as a constant value without

  1. SPATIAL MEMORY IMPAIRMENT AND HIPPOCAMPAL CELL LOSS INDUCED BY OKADAIC ACID (EXPERIMENTAL STUDY).

    PubMed

    Chighladze, M; Dashniani, M; Beselia, G; Kruashvili, L; Naneishvili, T

    2016-01-01

    In the present study, we evaluated and compared effect of intracerebroventricular (ICV) and intrahippocampal bilateral microinjection of okadaic acid (OA) on spatial memory function assessed in one day water maze paradigm and hippocampal structure in rats. Rats were divided in following groups: Control(icv) - rats injected with ICV and aCSF; Control(hipp) - rats injected intrahippocampally with aCSF; OAicv - rats injected with ICV and OA; OAhipp - rats injected intrahippocampally with OA. Nissl staining of hippocampal sections showed that the pyramidal cell loss in OAhipp group is significantly higher than that in the OAicv. The results of behavioral experiments showed that ICV or intrahippocampal bilateral microinjection of OA did not affect learning process and short-term spatial memory but induced impairment in spatial long-term memory assessed in probe test performance 24 h after training. OA-induced spatial memory impairment may be attributed to the hippocampal cell death. Based on these results OA induced memory deficit and hippocampal cell loss in rat may be considered as a potential animal model for preclinical evaluation of antidementic drug activity. PMID:26870981

  2. Dietary n-3 PUFAs Deficiency Increases Vulnerability to Inflammation-Induced Spatial Memory Impairment.

    PubMed

    Delpech, Jean-Christophe; Thomazeau, Aurore; Madore, Charlotte; Bosch-Bouju, Clementine; Larrieu, Thomas; Lacabanne, Chloe; Remus-Borel, Julie; Aubert, Agnès; Joffre, Corinne; Nadjar, Agnès; Layé, Sophie

    2015-11-01

    Dietary n-3 polyunsaturated fatty acids (PUFAs) are critical components of inflammatory response and memory impairment. However, the mechanisms underlying the sensitizing effects of low n-3 PUFAs in the brain for the development of memory impairment following inflammation are still poorly understood. In this study, we examined how a 2-month n-3 PUFAs deficiency from pre-puberty to adulthood could increase vulnerability to the effect of inflammatory event on spatial memory in mice. Mice were given diets balanced or deficient in n-3 PUFAs for a 2-month period starting at post-natal day 21, followed by a peripheral administration of lipopolysaccharide (LPS), a bacterial endotoxin, at adulthood. We first showed that spatial memory performance was altered after LPS challenge only in n-3 PUFA-deficient mice that displayed lower n-3/n-6 PUFA ratio in the hippocampus. Importantly, long-term depression (LTD), but not long-term potentiation (LTP) was impaired in the hippocampus of LPS-treated n-3 PUFA-deficient mice. Proinflammatory cytokine levels were increased in the plasma of both n-3 PUFA-deficient and n-3 PUFA-balanced mice. However, only n-3 PUFA-balanced mice showed an increase in cytokine expression in the hippocampus in response to LPS. In addition, n-3 PUFA-deficient mice displayed higher glucocorticoid levels in response to LPS as compared with n-3 PUFA-balanced mice. These results indicate a role for n-3 PUFA imbalance in the sensitization of the hippocampal synaptic plasticity to inflammatory stimuli, which is likely to contribute to spatial memory impairment. PMID:25948102

  3. Faithful teleportation of multi-particle states involving multi spatially remote agents via probabilistic channels

    NASA Astrophysics Data System (ADS)

    Jiang, Min; Li, Hui; Zhang, Zeng-ke; Zeng, Jia

    2011-02-01

    We present an approach to faithfully teleport an unknown quantum state of entangled particles in a multi-particle system involving multi spatially remote agents via probabilistic channels. In our scheme, the integrity of an entangled multi-particle state can be maintained even when the construction of a faithful channel fails. Furthermore, in a quantum teleportation network, there are generally multi spatially remote agents which play the role of relay nodes between a sender and a distant receiver. Hence, we propose two schemes for directly and indirectly constructing a faithful channel between the sender and the distant receiver with the assistance of relay agents, respectively. Our results show that the required auxiliary particle resources, local operations and classical communications are considerably reduced for the present purpose.

  4. Spatial structure, sampling design and scale in remotely-sensed imagery of a California savanna woodland

    NASA Technical Reports Server (NTRS)

    Mcgwire, K.; Friedl, M.; Estes, J. E.

    1993-01-01

    This article describes research related to sampling techniques for establishing linear relations between land surface parameters and remotely-sensed data. Predictive relations are estimated between percentage tree cover in a savanna environment and a normalized difference vegetation index (NDVI) derived from the Thematic Mapper sensor. Spatial autocorrelation in original measurements and regression residuals is examined using semi-variogram analysis at several spatial resolutions. Sampling schemes are then tested to examine the effects of autocorrelation on predictive linear models in cases of small sample sizes. Regression models between image and ground data are affected by the spatial resolution of analysis. Reducing the influence of spatial autocorrelation by enforcing minimum distances between samples may also improve empirical models which relate ground parameters to satellite data.

  5. Modulation of the spatial attention network by incentives in healthy aging and mild cognitive impairment.

    PubMed

    Bagurdes, Lisa A; Mesulam, Marsel M; Gitelman, Darren R; Weintraub, Sandra; Small, Dana M

    2008-10-01

    Impairments of spatial attention are common in Alzheimer's disease (AD), but may develop earlier in the course of the disease, a condition referred to as mild cognitive impairment (MCI). In a previous experiment, we showed that emotional content overcame the AD-related decline in selective attention to novel events [LaBar, K. S., Mesulam, M., Gitelman, D. R., & Weintraub, S. (2000). Emotional curiosity: Modulation of visuospatial attention by arousal is preserved in aging and early-stage Alzheimer's disease. Neuropsychologia, 38(13), 1734-1740]. The current experiment examined the influence of secondary reinforcers upon selective spatial attention in MCI and healthy aging (EC). Subjects performed a covert attention task while undergoing fMRI. They won money for fast responses and lost money for slow responses. In young subjects, this task had shown that the influence of incentive upon spatial attention is mediated by the posterior cingulate (PCC) and orbitofrontal cortices (OFC) [Small, D. M., Gitelman, D., Simmons, K., Bloise, S. M., Parrish, T., & Mesulam, M. M. (2005). Monetary incentives enhance processing in brain regions mediating top-down control of attention. Cerebral Cortex, 15(12), 1855-1865]. Both groups were able to use spatial cues to generate an anticipatory attentional shift towards the cued location. The prospect of winning (but not losing) money enhanced attentional shifts in EC subjects, an effect that was mediated by OFC activation. In contrast, only the prospect of losing money enhanced attentional shifts in MCI subjects, an effect that correlated with PCC activation. Behavioral effects of incentive upon spatial attention are only partially maintained in EC and MCI with corresponding modifications in the underlying neural circuitry. These results suggest a reorganization of the relationships between the limbic system and spatial attention network in healthy aging and MCI. PMID:18602410

  6. Geographic information systems, remote sensing, and spatial analysis activities in Texas, 2008-09

    USGS Publications Warehouse

    U.S. Geological Survey

    2009-01-01

    Geographic information system (GIS) technology has become an important tool for scientific investigation, resource management, and environmental planning. A GIS is a computer-aided system capable of collecting, storing, analyzing, and displaying spatially referenced digital data. GIS technology is useful for analyzing a wide variety of spatial data. Remote sensing involves collecting remotely sensed data, such as satellite imagery, aerial photography, or radar images, and analyzing the data to gather information or investigate trends about the environment or the Earth's surface. Spatial analysis combines remotely sensed, thematic, statistical, quantitative, and geographical data through overlay, modeling, and other analytical techniques to investigate specific research questions. It is the combination of data formats and analysis techniques that has made GIS an essential tool in scientific investigations. This fact sheet presents information about the technical capabilities and project activities of the U.S. Geological Survey (USGS) Texas Water Science Center (TWSC) GIS Workgroup during 2008 and 2009. After a summary of GIS Workgroup capabilities, brief descriptions of activities by project at the local and national levels are presented. Projects are grouped by the fiscal year (October-September 2008 or 2009) the project ends and include overviews, project images, and Internet links to additional project information and related publications or articles.

  7. A mobile agent approach to access and represent remote spatial information in LBS

    NASA Astrophysics Data System (ADS)

    Fang, Zhixiang; Li, Qingquan; Luo, Zhi; Geng, Xuexian

    2005-10-01

    The mobile computing based Location based Service (LBS) technology has been increasingly grown in the past decade; however there still exist some important constraints that complicate work with a mobile spatial information system. The limited resources in the mobile computing terminals would restrict some features that are available on the traditional computing technology. This paper will explores the use of a cooperative, distributed multi-agent systems (Java Agent Development Framework, JADE) to improve the efficiency of accessing and represent remote spatial information in mobile terminals and fixed terminal which support Java runtime environment (JRE), because that JADE system has following features: distributed agent platform, graphical user interface to manage several agents and agent containers form remote host, supporting to execution of multiple, parallel and concurrent agent activities via behavior model, FIPA-compliant platform including AMS (Agent Management System), DF (Directory Facilitator) and ACC (Agent Communication Channel), Efficient transport of ACL messages inside same agent system, library of FIPA interaction protocols ready to be used, FIPA-compliant naming service and supporting for application-defined content languages and ontology. An agile and flexible agent based approach for accessing and representing remote spatial information is proposed in this paper, mobile agent system architecture in LBS is presented, and a prototype system is given to shown that JADE makes this approach feasible and effective.

  8. Brain structural, functional, and cognitive correlates of recent versus remote autobiographical memories in amnestic Mild Cognitive Impairment

    PubMed Central

    Tomadesso, Clémence; Perrotin, Audrey; Mutlu, Justine; Mézenge, Florence; Landeau, Brigitte; Egret, Stéphanie; de la Sayette, Vincent; Jonin, Pierre-Yves; Eustache, Francis; Desgranges, Béatrice; Chételat, Gaël

    2015-01-01

    Deficits in autobiographical memory appear earlier for recent than for remote life periods over the course of Alzheimer's disease (AD). The present study aims to further our understanding of this graded effect by investigating the cognitive and neural substrates of recent versus remote autobiographical memories in patients with amnestic Mild Cognitive Impairment (aMCI) thanks to an autobiographical fluency task. 20 aMCI patients and 25 Healthy elderly Controls (HC) underwent neuropsychological tests assessing remote (20-to-30 years old) and recent (the ten last years) autobiographical memory as well as episodic and semantic memory, executive function and global cognition. All patients also had a structural MRI and an FDG-PET scan. Correlations were assessed between each autobiographical memory score and the other tests as well as grey matter volume and metabolism. Within the aMCI, performances for the remote period correlated with personal semantic memory and episodic memory retrieval whereas performances for the recent period only correlated with episodic memory retrieval. Neuroimaging analyses revealed significant correlations between performances for the remote period and temporal pole and temporo-parietal cortex volumes and anterior cingulate gyrus metabolism, while performances for the recent period correlated with hippocampal volume and posterior cingulate, medial prefrontal and hippocampus metabolism. The brain regions related with the retrieval of events from the recent period showed greater atrophy/hypometabolism in aMCI patients compared to HC than those involved in remote memories. Recall of recent memories essentially relies on episodic memory processes and brain network while remote memories also involve other processes such as semantic memory. This is consistent with the semanticization of memories with time and may explain the better resistance of remote memory in AD. PMID:26106572

  9. Explaining Spatial Variability in Wellbore Impairment Risk for Pennsylvania Oil and Gas Wells, 2000-2014

    NASA Astrophysics Data System (ADS)

    Santoro, R.; Ingraffea, A. R.

    2015-12-01

    Previous modeling (ingraffea et al. PNAS, 2014) indicated roughly two-times higher cumulative risk for wellbore impairment in unconventional wells, relative to conventional wells, and large spatial variation in risk for oil and gas wells drilled in the state of Pennsylvania. Impairment risk for wells in the northeast portion of the state were found to be 8.5-times greater than that of wells drilled in the rest of the state. Here, we set out to explain this apparent regional variability through Boosted Regression Tree (BRT) analysis of geographic, developmental, and general well attributes. We find that regional variability is largely driven by the nature of the development, i.e. whether conventional or unconventional development is dominant. Oil and natural gas market prices and total well depths present as major influences in wellbore impairment, with moderate influences from well densities and geologic factors. The figure depicts influence paths for predictors of impairments for the state (top left), SW region (top right), unconventional/NE region (bottom left) and conventional/NW region (bottom right) models. Influences are scaled to reflect percent contributions in explaining variability in the model.

  10. PPARγ activation prevents impairments in spatial memory and neurogenesis following transient illness

    PubMed Central

    Ormerod, Brandi K.; Hanft, Simon J.; Asokan, Aditya; Haditsch, Ursula; Lee, Star W.; Palmer, Theo D.

    2012-01-01

    The detrimental effects of illness on cognition are familiar to virtually everyone. Some effects resolve quickly while others may linger after the illness resolves. We found that a transient immune response stimulated by lipopolysaccharide (LPS) compromised hippocampal neurogenesis and impaired hippocampus-dependent spatial memory. The immune event caused a 50% reduction in the number of neurons generated during the illness and the onset of the memory impairment was delayed and coincided with the time when neurons generated during the illness would have become functional within the hippocampus. Broad spectrum non-steroidal anti-inflammatory drugs attenuated these effects but selective Cox-2 inhibition was ineffective while PPARγ activation was surprisingly effective at protecting both neurogenesis and memory from the effects of LPS-produced transient illness. These data may highlight novel mechanisms behind chronic inflammatory and neuroinflammatory episodes that are known to compromise hippocampus-dependent forms of learning and memory. PMID:23108061

  11. Mice with Deficient BK Channel Function Show Impaired Prepulse Inhibition and Spatial Learning, but Normal Working and Spatial Reference Memory

    PubMed Central

    Azzopardi, Erin; Ruettiger, Lukas; Ruth, Peter; Schmid, Susanne

    2013-01-01

    Genetic variations in the large-conductance, voltage- and calcium activated potassium channels (BK channels) have been recently implicated in mental retardation, autism and schizophrenia which all come along with severe cognitive impairments. In the present study we investigate the effects of functional BK channel deletion on cognition using a genetic mouse model with a knock-out of the gene for the pore forming α-subunit of the channel. We tested the F1 generation of a hybrid SV129/C57BL6 mouse line in which the slo1 gene was deleted in both parent strains. We first evaluated hearing and motor function to establish the suitability of this model for cognitive testing. Auditory brain stem responses to click stimuli showed no threshold differences between knockout mice and their wild-type littermates. Despite of muscular tremor, reduced grip force, and impaired gait, knockout mice exhibited normal locomotion. These findings allowed for testing of sensorimotor gating using the acoustic startle reflex, as well as of working memory, spatial learning and memory in the Y-maze and the Morris water maze, respectively. Prepulse inhibition on the first day of testing was normal, but the knockout mice did not improve over the days of testing as their wild-type littermates did. Spontaneous alternation in the y-maze was normal as well, suggesting that the BK channel knock-out does not impair working memory. In the Morris water maze knock-out mice showed significantly slower acquisition of the task, but normal memory once the task was learned. Thus, we propose a crucial role of the BK channels in learning, but not in memory storage or recollection. PMID:24303038

  12. star Miner: A suit of classifiers for spatial, temporal, ancillary, and remote sensing data mining

    SciTech Connect

    Vatsavai, Raju; Shekhar, Shashi; Burk, Thomas E; Bhaduri, Budhendra L

    2008-01-01

    Thematic classification of multi-spectral remotely sensed imagery for large geographic regions requires complex algorithms and feature selection techniques. Traditional statistical classifiers rely exclusively on spectral characteristics, but thematic classes are often spectrally overlapping. The spectral response distributions of thematic classes are dependent on many factors including terrain, slope, aspect, soil type, and atmospheric conditions present during the image acquisition. With the availability of geo-spatial databases, it is possible to exploit the knowledge derived from these ancillary geo-spatial databases to improve the classification accuracies. However, it is not easy to incorporate this additional knowledge into traditional statistical classification methods. On the other hand, knowledge-based and neural network classifiers can readily incorporate these spatial databases, but these systems are often complex to train and their accuracy is only slightly better than statistical classifiers. In this paper we present a new suit of classifiers developed through NASA funding, which addresses many of these problems and provide a framework for mining multi-spectral and temporal remote sensing images guided by geo-spatial databases.

  13. Sleep deprivation impairs spatial retrieval but not spatial learning in the non-human primate grey mouse lemur.

    PubMed

    Rahman, Anisur; Languille, Solène; Lamberty, Yves; Babiloni, Claudio; Perret, Martine; Bordet, Regis; Blin, Olivier J; Jacob, Tom; Auffret, Alexandra; Schenker, Esther; Richardson, Jill; Pifferi, Fabien; Aujard, Fabienne

    2013-01-01

    A bulk of studies in rodents and humans suggest that sleep facilitates different phases of learning and memory process, while sleep deprivation (SD) impairs these processes. Here we tested the hypothesis that SD could alter spatial learning and memory processing in a non-human primate, the grey mouse lemur (Microcebus murinus), which is an interesting model of aging and Alzheimer's disease (AD). Two sets of experiments were performed. In a first set of experiments, we investigated the effects of SD on spatial learning and memory retrieval after one day of training in a circular platform task. Eleven male mouse lemurs aged between 2 to 3 years were tested in three different conditions: without SD as a baseline reference, 8 h of SD before the training and 8 h of SD before the testing. The SD was confirmed by electroencephalographic recordings. Results showed no effect of SD on learning when SD was applied before the training. When the SD was applied before the testing, it induced an increase of the amount of errors and of the latency prior to reach the target. In a second set of experiments, we tested the effect of 8 h of SD on spatial memory retrieval after 3 days of training. Twenty male mouse lemurs aged between 2 to 3 years were tested in this set of experiments. In this condition, the SD did not affect memory retrieval. This is the first study that documents the disruptive effects of the SD on spatial memory retrieval in this primate which may serve as a new validated challenge to investigate the effects of new compounds along physiological and pathological aging. PMID:23717620

  14. The effects of L-arginine on spatial memory and synaptic plasticity impairments induced by lipopolysaccharide

    PubMed Central

    Anaeigoudari, Akbar; Shafei, Mohammad Naser; Soukhtanloo, Mohammad; Sadeghnia, Hamid Reza; Reisi, Parham; Nosratabadi, Reza; Behradnia, Sepehr; Hosseini, Mahmoud

    2015-01-01

    Background: An important role of nitric oxide (NO) in neuroinflammation has been suggested. It is also suggested that NO has a critical role in learning and memory. Neuro-inflammation induced by lipopolysaccharide (LPS) has been reported that deteriorates learning and memory. The effect of L-arginine (LA) as a precursor of NO on LPS-induced spatial learning and memory and neuronal plasticity impairment was evaluated. Materials and Methods: The animals were grouped into: (1) Control, (2) LPS, (3) LA-LPS, and (4) LA. The rats received intraperitoneally LPS (1 mg/kg) 2 h before experiments and LA (200 mg/kg) 30 min before LPS. The animals were examined in Morris water maze (MWM). Long-term potentiation (LTP) from CA1 area of the hippocampus was also assessed by 100 Hz stimulation in the ipsilateral Schaffer collateral pathway. Results: In MWM, time latency and traveled path were higher in LPS group than the control group (P < 0.001) whereas in LA-LPS group they were shorter than LPS group (P < 0.001). The amplitude and slope of field excitatory postsynaptic potential (fEPSP) decreased in LPS group compared to control group (P < 0.05 and P < 0.01) whereas, there was not any significant difference in these parameters between LPS and LA-LPS groups. Conclusion: Administration of LPS impaired spatial memory and synaptic plasticity. Although LA ameliorated deleterious effects of LPS on learning of spatial tasks, it could not restore LPS-induced LTP impairment. PMID:26601090

  15. Frontal and parietal theta burst TMS impairs working memory for visual-spatial conjunctions.

    PubMed

    Morgan, Helen M; Jackson, Margaret C; van Koningsbruggen, Martijn G; Shapiro, Kimron L; Linden, David E J

    2013-03-01

    In tasks that selectively probe visual or spatial working memory (WM) frontal and posterior cortical areas show a segregation, with dorsal areas preferentially involved in spatial (e.g. location) WM and ventral areas in visual (e.g. object identity) WM. In a previous fMRI study [1], we showed that right parietal cortex (PC) was more active during WM for orientation, whereas left inferior frontal gyrus (IFG) was more active during colour WM. During WM for colour-orientation conjunctions, activity in these areas was intermediate to the level of activity for the single task preferred and non-preferred information. To examine whether these specialised areas play a critical role in coordinating visual and spatial WM to perform a conjunction task, we used theta burst transcranial magnetic stimulation (TMS) to induce a functional deficit. Compared to sham stimulation, TMS to right PC or left IFG selectively impaired WM for conjunctions but not single features. This is consistent with findings from visual search paradigms, in which frontal and parietal TMS selectively affects search for conjunctions compared to single features, and with combined TMS and functional imaging work suggesting that parietal and frontal regions are functionally coupled in tasks requiring integration of visual and spatial information. Our results thus elucidate mechanisms by which the brain coordinates spatially segregated processing streams and have implications beyond the field of working memory. PMID:22483548

  16. Early Chronic Low-Level Methylmercury Poisoning in Monkeys Impairs Spatial Vision

    NASA Astrophysics Data System (ADS)

    Rice, Deborah C.; Gilbert, Steven G.

    1982-05-01

    Five monkeys were treated from birth with oral doses of mercury as methylmercury (50 micrograms per kilogram of body weight per day); concentrations in the blood peaked at 1.2 to 1.4 parts per million; and declined after weaning from infant formula to a steady level of 0.6 to 0.9 part per million. There were no overt signs of toxicity. When tested between 3 and 4 years of age under conditions of both high and low luminance, treated monkeys exhibited spatial vision that was impaired compared with that of control monkeys.

  17. Extraction Of Hydrological Parameters Using High Spatial Resolution Remote Sensing For KINEROS2 Model

    NASA Astrophysics Data System (ADS)

    Sadeh, Yuval; Blumberg, Dan G.; Cohen, Hai; Morin, Efrat; Maman, Shimrit

    2016-04-01

    Arid and semi-arid environments cover more than one-third of Earth's land surface; these environments are especially vulnerable to flash flood hazards due to the poor understanding of the phenomenon and the lack of meteorological, geomorphological, and hydrological data. For many years, catchment characteristics have been observed using point-based measurements such as rain gauges and soil sample analysis. Furthermore, flood modeling techniques are not always available in ungauged catchments or in regions where data are sparse. In comparison to point-based observations, using remote sensing technologies can provide continuous spatial hydrological parameters and variables. The advances in remote sensing technologies including weather radar-based quantitative precipitation estimation (QPE) and Earth observing satellites, provide new geo-spatial data using high spatial and temporal resolution for basin-scale geomorphological analysis and hydrological models. This study used high spatial resolution remote sensing to extract some of the main input parameters of Kinematic Runoff and Erosion Model (KINEROS2), for the arid medium size Rahaf watershed (76 km^2}), located in the Judean Desert, Israel. During the research a high resolution land cover map of Rahaf basin was created using WorldView-2 multispectral satellite imageries; surface roughness was estimated using SIR-C and COSMO-SkyMed Synthetic Aperture Radar (SAR) spaceborne sensors; and rainstorm characteristics were extracted from ground-based meteorological radar. Finally, all the remotely sensed extracted data were used as inputs for the KINEROS2 through Automated Geospatial Watershed Assessment (AGWA) tool. The model-simulated peak flow and volume were then compared to runoff measurements from the watershed's pouring point. This research demonstrates the ability of using remotely sensed extracted data as inputs for the KINEROS2 model. Using AGWA, each simulated storm was successfully calibrated, when the average

  18. Predicting spatial variations of tree species richness in tropical forests from high-resolution remote sensing.

    PubMed

    Fricker, Geoffrey A; Wolf, Jeffrey A; Saatchi, Sassan S; Gillespie, Thomas W

    2015-10-01

    There is an increasing interest in identifying theories, empirical data sets, and remote-sensing metrics that can quantify tropical forest alpha diversity at a landscape scale. Quantifying patterns of tree species richness in the field is time consuming, especially in regions with over 100 tree species/ha. We examine species richness in a 50-ha plot in Barro Colorado Island in Panama and test if biophysical measurements of canopy reflectance from high-resolution satellite imagery and detailed vertical forest structure and topography from light detection and ranging (lidar) are associated with species richness across four tree size classes (>1, 1-10, >10, and >20 cm dbh) and three spatial scales (1, 0.25, and 0.04 ha). We use the 2010 tree inventory, including 204,757 individuals belonging to 301 species of freestanding woody plants or 166 ± 1.5 species/ha (mean ± SE), to compare with remote-sensing data. All remote-sensing metrics became less correlated with species richness as spatial resolution decreased from 1.0 ha to 0.04 ha and tree size increased from 1 cm to 20 cm dbh. When all stems with dbh > 1 cm in 1-ha plots were compared to remote-sensing metrics, standard deviation in canopy reflectance explained 13% of the variance in species richness. The standard deviations of canopy height and the topographic wetness index (TWI) derived from lidar were the best metrics to explain the spatial variance in species richness (15% and 24%, respectively). Using multiple regression models, we made predictions of species richness across Barro Colorado Island (BCI) at the 1-ha spatial scale for different tree size classes. We predicted variation in tree species richness among all plants (adjusted r² = 0.35) and trees with dbh > 10 cm (adjusted r² = 0.25). However, the best model results were for understory trees and shrubs (dbh 1-10 cm) (adjusted r² = 0.52) that comprise the majority of species richness in tropical forests. Our results indicate that high

  19. Using remote sensing and machine learning for the spatial modelling of a bluetongue virus vector

    NASA Astrophysics Data System (ADS)

    Van doninck, J.; Peters, J.; De Baets, B.; Ducheyne, E.; Verhoest, N. E. C.

    2012-04-01

    Bluetongue is a viral vector-borne disease transmitted between hosts, mostly cattle and small ruminants, by some species of Culicoides midges. Within the Mediterranean basin, C. imicola is the main vector of the bluetongue virus. The spatial distribution of this species is limited by a number of environmental factors, including temperature, soil properties and land cover. The identification of zones at risk of bluetongue outbreaks thus requires detailed information on these environmental factors, as well as appropriate epidemiological modelling techniques. We here give an overview of the environmental factors assumed to be constraining the spatial distribution of C. imicola, as identified in different studies. Subsequently, remote sensing products that can be used as proxies for these environmental constraints are presented. Remote sensing data are then used together with species occurrence data from the Spanish Bluetongue National Surveillance Programme to calibrate a supervised learning model, based on Random Forests, to model the probability of occurrence of the C. imicola midge. The model will then be applied for a pixel-based prediction over the Iberian peninsula using remote sensing products for habitat characterization.

  20. Using remote sensing products to classify landscape. A multi-spatial resolution approach

    NASA Astrophysics Data System (ADS)

    García-Llamas, Paula; Calvo, Leonor; Álvarez-Martínez, José Manuel; Suárez-Seoane, Susana

    2016-08-01

    The European Landscape Convention encourages the inventory and characterization of landscapes for environmental management and planning actions. Among the range of data sources available for landscape classification, remote sensing has substantial applicability, although difficulties might arise when available data are not at the spatial resolution of operational interest. We evaluated the applicability of two remote sensing products informing on land cover (the categorical CORINE map at 30 m resolution and the continuous NDVI spectral index at 1 km resolution) in landscape classification across a range of spatial resolutions (30 m, 90 m, 180 m, 1 km), using the Cantabrian Mountains (NW Spain) as study case. Separate landscape classifications (using topography, urban influence and land cover as inputs) were accomplished, one per each land cover dataset and spatial resolution. Classification accuracy was estimated through confusion matrixes and uncertainty in terms of both membership probability and confusion indices. Regarding landscape classifications based on CORINE, both typology and number of landscape classes varied across spatial resolutions. Classification accuracy increased from 30 m (the original resolution of CORINE) to 90m, decreasing towards coarser resolutions. Uncertainty followed the opposite pattern. In the case of landscape classifications based on NDVI, the identified landscape patterns were geographically structured and showed little sensitivity to changes across spatial resolutions. Only the change from 1 km (the original resolution of NDVI) to 180 m improved classification accuracy. The value of confusion indices increased with resolution. We highlight the need for greater effort in selecting data sources at the suitable spatial resolution, matching regional peculiarities and minimizing error and uncertainty.

  1. Modelling Spatial Hydrologic Patterns Using Physically-Based Models Driven by Remote- Sensing and Reanalysis Data

    NASA Astrophysics Data System (ADS)

    Liu, M.; Bardossy, A.

    2008-12-01

    Due to the interaction with energy inputs (solar radiation, precipitation, and wind, etc.), natural catchments tend to evolve to an equilibrium state characterized by stable spatial patterns of vegetation, topography, soil distribution and river system, which in turn lead to stable patterns of certain hydrological variables, i.e., soil moisture, evapotranspiration, and snow cover. In this work, these three important hydrologic parameters have been investigated at a fine scale (500m to 1000m). The authors start from obtaining the spatial patterns of basic meteorological inputs with physically based models driven by globally available data, i.e., spatial solar radiation is generated by radiation models, and spatial wind is obtained by a meso-scale meteorological model driven by NCEP/NCAR reanalysis data. The SWAP model has been adapted to calculate the evapotranspiration and soil moisture at grid scale. The approach is validated in SADC (Southern African Development Community) region with the remote sensing soil moisture data available from ESA TIGER Innovator project. In a parallel study, MODIS snow cover data has been reconstructed applying a spatial and temporal filter with land surface temperature as auxiliary information, to investigate the characteristics of its spatial distribution. In both studies, statistical analysis reveals a strong relationship between the hydrological variables and topography, as well as land cover. Since the approach is based on physically based models and driven by globally available data, it is general for any catchment and time period.

  2. Chronic Alcohol Consumption Impairs Visuo-Spatial Associative Memory in Periadolescent Rhesus Monkeys

    PubMed Central

    Crean, Rebecca D.; Vandewater, Sophia A.; Katner, Simon N.; Huitron-Resendiz, Salvador

    2010-01-01

    Alcohol abuse in the adult is often preceded by high alcohol consumption during adolescence. Profound changes in brain structure and function occur during this developmental period, therefore alcohol may impact essential cognitive skill development during the formal educational years. The objective of this study was to determine if chronic oral alcohol intake slows acquisition and performance of cognitive tasks in male adolescent rhesus monkeys. Treatment groups (Alcohol, N=4; Control, N=3) were evaluated on bimanual dexterity and tests of visuo-spatial memory and learning adapted from the Cambridge Neuropsychological Test Automated Battery. Animals were trained daily in 30 min sessions and had subsequent access to alcohol/Tang® solutions (Alcohol group) or Tang® only (Control group) Monday through Friday for 11 months. Recordings of brainstem auditory evoked potentials (BSAEP) were conducted periodically before and during the chronic drinking. Results Chronic alcohol drinking (ave of 1.78g/kg alcohol per session) impaired behavioral performance assessed ~22 hrs after the prior drinking session. The Alcohol group required more trials than the Control group to reach criterion on the visuo-spatial memory task and showed increased sensitivity to trial difficulty and retention interval. Alcohol animals also had slowed initial acquisition of the bimanual task. The latency of P4 and P5 BSAEP peaks were also delayed in the Alcohol group. Chronic alcohol consumption impaired the acquisition and performance of a spatial memory task and disrupted brainstem auditory processing, thus these results show that repeated alcohol exposure in adolescence interferes with a range of brain functions including complex visuo-spatial mnemonic processing. PMID:20951512

  3. Poststroke Hemiparesis Impairs the Rate but not Magnitude of Adaptation of Spatial and Temporal Locomotor Features

    PubMed Central

    Savin, Douglas N.; Tseng, Shih-Chiao; Whitall, Jill; Morton, Susanne M.

    2015-01-01

    Background Persons with stroke and hemiparesis walk with a characteristic pattern of spatial and temporal asymmetry that is resistant to most traditional interventions. It was recently shown in nondisabled persons that the degree of walking symmetry can be readily altered via locomotor adaptation. However, it is unclear whether stroke-related brain damage affects the ability to adapt spatial or temporal gait symmetry. Objective Determine whether locomotor adaptation to a novel swing phase perturbation is impaired in persons with chronic stroke and hemiparesis. Methods Participants with ischemic stroke (14) and nondisabled controls (12) walked on a treadmill before, during, and after adaptation to a unilateral perturbing weight that resisted forward leg movement. Leg kinematics were measured bilaterally, including step length and single-limb support (SLS) time symmetry, limb angle center of oscillation, and interlimb phasing, and magnitude of “initial” and “late” locomotor adaptation rates were determined. Results All participants had similar magnitudes of adaptation and similar initial adaptation rates both spatially and temporally. All 14 participants with stroke and baseline asymmetry temporarily walked with improved SLS time symmetry after adaptation. However, late adaptation rates poststroke were decreased (took more strides to achieve adaptation) compared with controls. Conclusions Mild to moderate hemiparesis does not interfere with the initial acquisition of novel symmetrical gait patterns in both the spatial and temporal domains, though it does disrupt the rate at which “late” adaptive changes are produced. Impairment of the late, slow phase of learning may be an important rehabilitation consideration in this patient population. PMID:22367915

  4. Peripheral orthopaedic surgery down-regulates hippocampal brain-derived neurotrophic factor and impairs remote memory in mouse.

    PubMed

    Fidalgo, A R; Cibelli, M; White, J P M; Nagy, I; Noormohamed, F; Benzonana, L; Maze, M; Ma, D

    2011-09-01

    Peripheral orthopaedic surgery induces a profound inflammatory response. This includes a substantial increase in cytokines and, especially, in the level of interleukin (IL)-1β in the hippocampus, which has been shown to impair hippocampal-dependent memory in mice. We have employed two tests of contextual remote memory to demonstrate that the inflammatory response to surgical insult in mice also results in impairment of remote memory associated with prefrontal cortex (PFC). We have also found that, under the conditions presented in the social interaction test, peripheral orthopaedic surgery does not increase anxiety-like behaviour in our animal model. Although such surgery induces an increase in the level of IL-1β in the hippocampus, it fails to do so in the PFC. Peripheral orthopaedic surgery also results in a reduction in the level of hippocampal brain-derived neurotrophic factor (BDNF) and this may contribute, in part, to the memory impairment found after such surgery. Our data suggest that a reduction in the level of hippocampal BDNF and an increase in the level of hippocampal IL-1β following surgery may affect the transference of fear memory in the mouse brain. PMID:21699962

  5. A Study of the Effects of Visual Occlusion on Motor and Spatial Learning in Visually Impaired Adults.

    ERIC Educational Resources Information Center

    Palmer, James L.; Elliott, Jeffrey; Kuyk, T. K.

    1998-01-01

    This study compared effects of visual occlusion on the motor and spatial learning of 28 legally blind adult males, half due to acuity loss and half due to peripheral field restriction. For both groups, occlusion appeared neither to facilitate nor impede motor learning but did significantly impair acquisition of spatial relations. Results have…

  6. Global hypoxia induced impairment in learning and spatial memory is associated with precocious hippocampal aging.

    PubMed

    Biswal, Suryanarayan; Sharma, Deepti; Kumar, Kushal; Nag, Tapas Chandra; Barhwal, Kalpana; Hota, Sunil Kumar; Kumar, Bhuvnesh

    2016-09-01

    Both chronological aging and chronic hypoxia stress have been reported to cause degeneration of hippocampal CA3 neurons and spatial memory impairment through independent pathways. However, the possible occurrence of precocious biological aging on exposure to single episode of global hypoxia resulting in impairment of learning and memory remains to be established. The present study thus aimed at bridging this gap in existing literature on hypoxia induced biological aging. Male Sprague Dawley rats were exposed to simulated hypobaric hypoxia (25,000ft) for different durations and were compared with aged rats. Behavioral studies in Morris Water Maze showed decline in learning abilities of both chronologically aged as well as hypoxic rats as evident from increased latency and pathlength to reach target platform. These behavioral changes in rats exposed to global hypoxia were associated with deposition of lipofuscin and ultrastructural changes in the mitochondria of hippocampal neurons that serve as hallmarks of aging. A single episode of chronic hypobaric hypoxia exposure also resulted in the up-regulation of pro-aging protein, S100A9 and down regulation of Tau, SNAP25, APOE and Sod2 in the hippocampus similar to that in aged rats indicating hypoxia induced accelerated aging. The present study therefore provides evidence for role of biological aging of hippocampal neurons in hypoxia induced impairment of learning and memory. PMID:27246251

  7. Impaired spatial selectivity and intact phase precession in two-dimensional virtual reality.

    PubMed

    Aghajan, Zahra M; Acharya, Lavanya; Moore, Jason J; Cushman, Jesse D; Vuong, Cliff; Mehta, Mayank R

    2015-01-01

    During real-world (RW) exploration, rodent hippocampal activity shows robust spatial selectivity, which is hypothesized to be governed largely by distal visual cues, although other sensory-motor cues also contribute. Indeed, hippocampal spatial selectivity is weak in primate and human studies that use only visual cues. To determine the contribution of distal visual cues only, we measured hippocampal activity from body-fixed rodents exploring a two-dimensional virtual reality (VR). Compared to that in RW, spatial selectivity was markedly reduced during random foraging and goal-directed tasks in VR. Instead we found small but significant selectivity to distance traveled. Despite impaired spatial selectivity in VR, most spikes occurred within ∼2-s-long hippocampal motifs in both RW and VR that had similar structure, including phase precession within motif fields. Selectivity to space and distance traveled were greatly enhanced in VR tasks with stereotypical trajectories. Thus, distal visual cues alone are insufficient to generate a robust hippocampal rate code for space but are sufficient for a temporal code. PMID:25420065

  8. Spatial Distribution and Pattern Persistence of Surface Soil Moisture and Temperature Over Prairie from Remote Sensing

    NASA Technical Reports Server (NTRS)

    Chen, Daoyi; Engman, Edwin T.; Brutsaert, Wilfried

    1997-01-01

    Images remotely sensed aboard aircraft during FIFE, namely, PBMR (microwave) soil moisture and NS001 thermal infrared surface temperature, were mapped on the same coordinate system covering the 20 km x 20 km experimental site. For both kinds of image data, the frequency distributions were close to symmetric, and the area average compared reasonably well with the ground based measurements. For any image on any given day, the correlation between the remotely sensed values and collocated ground based measurements over the area was usually high in the case of NS001 surface temperature but low in the case of PBMR soil moisture. On the other hand, at any given flux station the correlation between the PBMR and gravimetric soil moisture over all available days was usually high. The correlation pixel by pixel between images of PBMR on different days was generally high. The preservation of the spatial patterns of soil moisture was also evaluated by considering the correlation station by station between ground-based soil moisture measurements on different days; no persistence of spatial pattern was apparent during wet periods, but a definite pattern gradually established itself toward the end of each drying episode. The spatial patterns of surface temperature revealed by NS001 were not preserved even within a single day. The cross-correlations among the two kinds of images and the vegetation index NDVI were normally poor. This suggests that different processes of vegetation growth, and of the near-surface soil water and energy budgets.

  9. Using remote sensing to study mangroves spatial dynamics under increased nitrogen availability and lower salinity conditions

    NASA Astrophysics Data System (ADS)

    Silvestri, S.; Whigham, D.; Laanbroek, R.; Rains, M. C.; Verhoeven, J.

    2014-12-01

    The impact of a strong change in the hydrologic conditions of an impoundment in the Indian River Lagoon (FL) dominated by Black mangrove (Avicennia germinans) has been monitored through field campaigns and remote sensing data analysis. The management solution adopted since the spring of 2009 to reduce the number of noxious insects involved pumping estuarine water in the spring and summer seasons. Satellite and airborne data with medium to high spatial resolution have been used to perform a change detection analysis and study the evolution of the spatial distribution of mangrove trees. Empirical relations of vegetation indexes with field data collected over time have been determined, and specifically the correlation with leaf production, branch length increment, soil moisture and salinity, soil NH4 concentration and nitrification/denitrification processes. The field data had already shown how locally the higher nitrogen availability and the lower soil salinity increased Black mangrove growth mainly in areas with dwarf and sparse mangrove cover. The use of high spatial resolution remote sensing has been of key importance to extend this result at the impoundment scale, showing how mangroves expanded overtime.

  10. Anisotropic spectral-spatial total variation model for multispectral remote sensing image destriping.

    PubMed

    Chang, Yi; Yan, Luxin; Fang, Houzhang; Luo, Chunan

    2015-06-01

    Multispectral remote sensing images often suffer from the common problem of stripe noise, which greatly degrades the imaging quality and limits the precision of the subsequent processing. The conventional destriping approaches usually remove stripe noise band by band, and show their limitations on different types of stripe noise. In this paper, we tentatively categorize the stripes in remote sensing images in a more comprehensive manner. We propose to treat the multispectral images as a spectral-spatial volume and pose an anisotropic spectral-spatial total variation regularization to enhance the smoothness of solution along both the spectral and spatial dimension. As a result, a more comprehensive stripes and random noise are perfectly removed, while the edges and detail information are well preserved. In addition, the split Bregman iteration method is employed to solve the resulting minimization problem, which highly reduces the computational load. We extensively validate our method under various stripe categories and show comparison with other approaches with respect to result quality, running time, and quantitative assessments. PMID:25706634

  11. Memantine attenuates the impairment of spatial learning and memory of pentylenetetrazol-kindled rats.

    PubMed

    Jia, Li-Jing; Wang, Wei-Ping; Li, Zhou-Ping; Zhen, Jun-Li; An, Li-Wei; Duan, Rui-Sheng

    2011-08-01

    Cognitive disorders after epilepsy can have a great impact on the quality of life of epileptic patients, though it has not drawn much attention. Even after identified, it is often undertreated or has gone untreated. Memantine has been approved to treat moderate to severe Alzheimer disease (AD), which is characterized by cognitive impairment. In present study, we determined the effects of memantine on PTZ-kindled rats, which can mimic the postseizure dysfunction that resembles symptoms observed in human epilepsy. We found that memantine can ameliorate the spatial learning and memory of epileptic rats. But contrary to previous claims that memantine can improve cognition in AD patients, without serious side effects on normal learning and memory abilities, we found that rats treated only with memantine exhibited the impaired spatial learning and memory ability. We conclude that memantine can improve cognition related to an excitotoxicity-induced pathologic state, but the potential side effects of memantine on the physiological processes should be considered. PMID:21479611

  12. Selective Impairment of Spatial Cognition Caused by Autoantibodies to the N-Methyl-D-Aspartate Receptor.

    PubMed

    Chang, Eric H; Volpe, Bruce T; Mackay, Meggan; Aranow, Cynthia; Watson, Philip; Kowal, Czeslawa; Storbeck, Justin; Mattis, Paul; Berlin, RoseAnn; Chen, Huiyi; Mader, Simone; Huerta, Tomás S; Huerta, Patricio T; Diamond, Betty

    2015-07-01

    Patients with systemic lupus erythematosus (SLE) experience cognitive abnormalities in multiple domains including processing speed, executive function, and memory. Here we show that SLE patients carrying antibodies that bind DNA and the GluN2A and GluN2B subunits of the N-methyl-d-aspartate receptor (NMDAR), termed DNRAbs, displayed a selective impairment in spatial recall. Neural recordings in a mouse model of SLE, in which circulating DNRAbs penetrate the hippocampus, revealed that CA1 place cells exhibited a significant expansion in place field size. Structural analysis showed that hippocampal pyramidal cells had substantial reductions in their dendritic processes and spines. Strikingly, these abnormalities became evident at a time when DNRAbs were no longer detectable in the hippocampus. These results suggest that antibody-mediated neurocognitive impairments may be highly specific, and that spatial cognition may be particularly vulnerable to DNRAb-mediated structural and functional injury to hippocampal cells that evolves after the triggering insult is no longer present. PMID:26286205

  13. Ketogenic diet attenuates spatial and item memory impairment in pentylenetetrazol-kindled rats.

    PubMed

    Jiang, Yan; Lu, Yuqiang; Jia, Mengmeng; Wang, Xiaohang; Zhang, Zhengxiang; Hou, Qun; Wang, Baohui

    2016-09-01

    The ketogenic diet (KD) controls seizure and improves cognition in patients with drug refractory epilepsy. However, few experimental models have shown this neuroprotective effect on cognition. In this study, we investigated the cognitive protective effects of KD in pentylenetetrazol (PTZ)-kindled rats. We used two relatively low-stress behavioral assessment methods, the novel object recognition (NOR) task and the novel placement recognition (NPR) task, to reveal impairment in item and spatial memory, respectively. We used the Morris water maze (MWM) test for comparisons amongst memory assessment methods. The KD group had a slower body weight gain and shorter bregma-lambda length than the control normal diet (ND) group. KD did not increase anxiety or decrease motor activities in an open-field test. KD attenuated the decrease in exploration ratio both in NOR and NPR tasks in kindled rats. Compared to the kindled ND rats, kindled KD rats stayed longer in target quarter during the probe trial testing of MWM. However, there were no differences in memory acquisition based on the MWM test results. In conclusion, KD attenuated the spatial and item memory impairment in PTZ-induced seizures. PMID:27343950

  14. The Visual Spatial Learning Test: differential impairment during the premanifest and manifest stages of Huntington's disease.

    PubMed

    Pirogovsky, Eva; Nicoll, Diane R; Challener, Dillon M; Breen, Elizabeth; Gluhm, Shea; Corey-Bloom, Jody; Gilbert, Paul E

    2015-03-01

    Visual spatial memory was assessed using the Visual Spatial Learning Test (VSLT) in individuals with mild to moderate Huntington's disease (HD), pre-manifest gene carriers for HD, and demographically similar controls. The VSLT has been demonstrated to be a valid, normed measure of non-verbal memory involving minimal motoric responses. The VSLT assesses immediate and delayed memory for designs, positions of the designs, and design/position associations. The HD group was significantly impaired (p < .05) relative to both the control and Pre-HD groups on immediate and delayed memory for the designs, positions, and design/position associations. Although there were no differences between the Pre-HD and control groups on immediate or delayed memory for designs or positions, the Pre-HD group was significantly impaired (p < .05) relative to the control group on immediate and delayed memory for design/position associations. The results offer novel insight into a relatively unexamined memory deficit that may occur in gene carriers for HD prior to phenoconversion. The data indicate that the VSLT may be a useful measure of visuospatial memory during the premanifest and manifest stages of HD. PMID:24330469

  15. Exploratory, anxiety and spatial memory impairments are dissociated in mice lacking the LPA1 receptor

    PubMed Central

    Castilla-Ortega, Estela; Sánchez-López, Jorge; Hoyo-Becerra, Carolina; Matas-Rico, Elisa; Zambrana-Infantes, Emma; Chun, Jerold; Fonseca, Fernando Rodríguez De; Pedraza, Carmen; Estivill-Torrús, Guillermo; Santin, Luis J.

    2013-01-01

    Lysophosphatidic acid (LPA) is a new, intercellular signalling molecule in the brain that has an important role in adult hippocampal plasticity. Mice lacking the LPA1 receptor exhibit motor, emotional and cognitive alterations. However, the potential relationship among these concomitant impairments was unclear. Wild-type and maLPA1-null mice were tested on the hole-board for habituation and spatial learning. MaLPA1-null mice exhibited reduced exploration in a novel context and a defective intersession habituation that also revealed increased anxiety-like behaviour throughout the hole-board testing. In regard to spatial memory, maLPA1 nulls failed to reach the controls’ performance at the end of the reference memory task. Moreover, their defective working memory on the first training day suggested a delayed acquisition of the task’s working memory rule, which is also a long term memory component. The temporal interval between trials and the task’s difficulty may explain some of the deficits found in these mice. Principal components analysis revealed that alterations found in each behavioural dimension were independent. Therefore, exploratory and emotional impairments did not account for the cognitive deficits that may be attributed to maLPA1 nulls’ hippocampal malfunction. PMID:20388543

  16. Hippocampal synaptic plasticity and spatial learning are impaired in a rat model of sleep fragmentation.

    PubMed

    Tartar, Jaime L; Ward, Christopher P; McKenna, James T; Thakkar, Mahesh; Arrigoni, Elda; McCarley, Robert W; Brown, Ritchie E; Strecker, Robert E

    2006-05-01

    Sleep fragmentation, a symptom in many clinical disorders, leads to cognitive impairments. To investigate the mechanisms by which sleep fragmentation results in memory impairments, rats were awakened once every 2 min via 30 s of slow movement on an automated treadmill. Within 1 h of this sleep interruption (SI) schedule, rats began to sleep in the 90-s periods without treadmill movement. Total non-rapid eye movement sleep (NREM) sleep time did not change over the 24 h of SI, although there was a significant decline in rapid eye movement sleep (REM) sleep and a corresponding increase in time spent awake. In the SI group, the mean duration of sleep episodes decreased and delta activity during periods of wake increased. Control rats either lived in the treadmill without movement (cage controls, CC), or had 10-min periods of movement followed by 30 min of non-movement allowing deep/continuous sleep (exercise controls, EC). EC did not differ from baseline in the total time spent in each vigilance state. Hippocampal long-term potentiation (LTP), a long-lasting change in synaptic efficacy thought to underlie declarative memory formation, was absent in rats exposed to 24 and 72 h SI. In contrast, LTP was normal in EC rats. However, long-term depression and paired-pulse facilitation were unaltered by 24 h SI. Twenty-four hour SI also impaired acquisition of spatial learning in the hippocampus-dependent water maze test. Twenty-four hour SI elevated plasma corticosterone (CORT) to levels previously shown to enhance LTP (125 ng/mL). The results suggest that sleep fragmentation negatively impacts spatial learning. Loss of N-methyl-D-aspartate (NMDA) receptor-dependent LTP in the hippocampal CA1 region may be one mechanism involved in this deficit. PMID:16817877

  17. Spatial Scaling Assessment of Surface Soil Moisture Estimations Using Remotely Sensed Data for Precision Agriculture

    NASA Astrophysics Data System (ADS)

    Hassan Esfahani, L.; Torres-Rua, A. F.; Jensen, A.; McKee, M.

    2014-12-01

    Airborne and Landsat remote sensing are promising technologies for measuring the response of agricultural crops to variations in several agricultural inputs and environmental conditions. Of particular significance to precision agriculture is surface soil moisture, a key component of the soil water balance, which addresses water and energy exchanges at the surface/atmosphere interface and affects vegetation health. Its estimation using the spectral reflectance of agricultural fields could be of value to agricultural management decisions. While top soil moisture can be estimated using radiometric information from aircraft or satellites and data mining techniques, comparison of results from two different aerial platforms might be complicated because of the differences in spatial scales (high resolution of approximately 0.15m versus coarser resolutions of 30m). This paper presents a combined modeling and scale-based approach to evaluate the impact of spatial scaling in the estimation of surface soil moisture content derived from remote sensing data. Data from Landsat 7 ETM+, Landsat 8 OLI and AggieAirTM aerial imagery are utilized. AggieAirTM is an airborne remote sensing platform developed by Utah State University that includes an autonomous Unmanned Aerial System (UAS) which captures radiometric information at visual, near-infrared, and thermal wavebands at spatial resolutions of 0.15 m or smaller for the optical cameras and about 0.6 m or smaller for the thermal infrared camera. Top soil moisture maps for AggieAir and Landsat are developed and statistically compared at different scales to determine the impact in terms of quantitative predictive capability and feasibility of applicability of results in improving in field management.

  18. Advanced Remote-Sensing Imaging Emission Spectrometer (ARIES): AIRS Spectral Resolution with MODIS Spatial Resolution

    NASA Technical Reports Server (NTRS)

    Pagano, Thomas S.; Chahine, Moustafa T.; Aumann, Hartmut H.; OCallaghan, Fred

    2006-01-01

    The Advanced Remote-sensing Imaging Emission Spectrometer (ARIES) will measure a wide range of earth quantities fundamental to the study of global climate change. It will build upon the success of the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Atmospheric Infrared Sounder (AIRS) instruments currently flying on the EOS Aqua Spacecraft. Both instruments are facility instruments for NASA providing data to thousands of scientists investigating land, ocean and atmospheric Earth System processes. ARIES will meet all the requirements of AIRS and MODIS in a single compact instrument, while providing the next-generation capability of improved spatial resolution for AIRS and improved spectral resolution for MODIS.

  19. Estimation of Spatially Distributed Evapotranspiration Using Remote Sensing and a Relevance Vector Machine

    NASA Astrophysics Data System (ADS)

    Maslova, I.; Bachour, R.; Walker, W. R.; Ticlavilca, A. M.; McKee, M.

    2014-12-01

    With the development of surface energy balance analyses, remote sensing has become a spatially explicit and quantitative methodology for understanding evapotranspiration (ET), a critical requirement for water resources planning and management. Limited temporal resolution of satellite images and cloudy skies present major limitations that impede continuous estimates of ET. This study introduces a practical approach that overcomes (in part) the previous limitations by implementing machine learning techniques that are accurate and robust. The analysis was applied to the Canal B service area of the Delta Canal Company in central Utah using data from the 2009-2011 growing seasons. Actual ET was calculated by an algorithm using data from satellite images. A relevance vector machine (RVM), which is a sparse Bayesian regression, was used to build a spatial model for ET. The RVM was trained with a set of inputs consisting of vegetation indexes, crops, and weather data. ET estimated via the algorithm was used as an output. The developed RVM model provided an accurate estimation of spatial ET based on a Nash-Sutcliffe coefficient (E) of 0.84 and a root-mean-squared error (RMSE) of 0.5 mmday-1. This methodology lays the groundwork for estimating ET at a spatial scale for the days when a satellite image is not available. It could also be used to forecast daily spatial ET if the vegetation indexes model inputs are extrapolated in time and the reference ET is forecasted accurately.

  20. Spatial representativeness of soil moisture using in situ, remote sensing, and land reanalysis data

    NASA Astrophysics Data System (ADS)

    Nicolai-Shaw, Nadine; Hirschi, Martin; Mittelbach, Heidi; Seneviratne, Sonia I.

    2015-10-01

    This study investigates the spatial representativeness of the temporal dynamics of absolute soil moisture and its temporal anomalies over North America based on a range of data sets. We use three main data sources: in situ observations, the remote-sensing-based data set of the European Space Agency Climate Change Initiative on the Essential Climate Variable soil moisture (ECV-SM), and land surface model estimates from European Centre for Medium-Range Weather Forecasts's ERA-Land. The intercomparisons of the three soil moisture data sources are performed at the in situ locations as well as for the full-gridded products. The applied method allows us to quantify the spatial footprint of soil moisture. At the in situ locations it is shown that for absolute soil moisture the ECV-SM and ERA-Land products perform similarly, while for the temporal anomalies the ECV-SM product shows more similarity in spatial representativeness with the in situ data. When taking into account all grid cells of the ECV-SM and ERA-Land products to calculate spatial representativeness, we find the largest differences in spatial representativeness for the absolute values. The differences in spatial representativeness between the single products can be related to some of their intrinsic characteristics, i.e., for ECV-SM low similarities are found in topographically complex terrain and areas with dense vegetation, while for ERA-Land the smoothed model topography and surface properties affect soil moisture and its spatial representativeness. Additionally, we show that the applied method is robust and can be used to analyze existing networks to provide insight into the locations in which higher station density would be of most benefit.

  1. Integrating field sampling, spatial statistics and remote sensing to map wetland vegetation in the Pantanal, Brazil

    NASA Astrophysics Data System (ADS)

    Arieira, J.; Karssenberg, D.; de Jong, S. M.; Addink, E. A.; Couto, E. G.; Nunes da Cunha, C.; Skøien, J. O.

    2010-09-01

    To improve the protection of wetlands, it is imperative to have a thorough understanding of their structuring elements and of the identification of efficient methods to describe and monitor them. This article uses sophisticated statistical classification, interpolation and error propagation techniques, in order to describe vegetation spatial patterns, map plant community distribution and evaluate the capability of statistical approaches to produce high-quality vegetation maps. The approach results in seven vegetation communities with a known floral composition that can be mapped over large areas using remotely sensed data. The relations between remotely sensing data and vegetation patterns, captured in four factorial axes, were formalized mathematically in multiple linear regression models and used in a universal kriging procedure to reduce the uncertainty in mapped communities. Universal kriging has shown to be a valuable interpolation technique because parts of vegetation variability not explained by the images could be modeled as spatially correlated residuals, increasing prediction accuracy. Differences in spatial dependence of the vegetation gradients evidenced the multi-scale nature of vegetation communities. Cross validation procedures and Monte Carlo simulations were used to quantify the uncertainty in the resulting map. Cross-validation showed that accuracy in classification varies according with the community type, as a result of sampling density and configuration. A map of uncertainty resulted from Monte Carlo simulations displayed the spatial variation in classification accuracy, showing that the quality of classification varies spatially, even though the proportion and arrangement of communities observed in the original map is preserved to a great extent. These results suggested that mapping improvement could be achieved by increasing the number of field observations of those communities with a scattered and small patch size distribution; or by

  2. Extracting temporal and spatial information from remotely sensed data for mapping wildlife habitat

    NASA Astrophysics Data System (ADS)

    Wallace, Cynthia S. A.

    The research accomplished in this dissertation used both mathematical and statistical techniques to extract and evaluate measures of landscape temporal dynamics and spatial structure from remotely sensed data for the purpose of mapping wildlife habitat. By coupling the landscape measures gleaned from the remotely sensed data with various sets of animal sightings and population data, effective models of habitat preference were created. Measures of temporal dynamics of vegetation greenness as measured by National Oceanographic and Atmospheric Administration's Advanced Very High Resolution Radiometer (AVHRR) satellite were used to effectively characterize and map season specific habitat of the Sonoran pronghorn antelope, as well as produce preliminary models of potential yellow-billed cuckoo habitat in Arizona. Various measures that capture different aspects of the temporal dynamics of the landscape were derived from AVHRR Normalized Difference Vegetation Index composite data using three main classes of calculations: basic statistics, standardized principal components analysis, and Fourier analysis. Pronghorn habitat models based on the AVHRR measures correspond visually and statistically to GIS-based models produced using data that represent detailed knowledge of ground-condition. Measures of temporal dynamics also revealed statistically significant correlations with annual estimates of elk population in selected Arizona Game Management Units, suggesting elk respond to regional environmental changes that can be measured using satellite data. Such relationships, once verified and established, can be used to help indirectly monitor the population. Measures of landscape spatial structure derived from IKONOS high spatial resolution (1-m) satellite data using geostatistics effectively map details of Sonoran pronghorn antelope habitat. Local estimates of the nugget, sill, and range variogram parameters calculated within 25 x 25-meter image windows describe the spatial

  3. Retrieving LAI from Remotely Sensed Images: Spectral Indices vs. Spatial Texture

    NASA Astrophysics Data System (ADS)

    Song, C.; Gray, J. M.; Zhang, S.

    2008-12-01

    Leaves are the interface where energy and gas exchanges between the atmosphere and forest ecosystems occur. Accurate knowledge of the amount leaves is essential to successfully modeling the fluxes of water and carbon through the earth's forests. Leaf area index (LAI) is a parameter used to quantify the abundance of leaves in a given stand. Remote sensing offers the only feasible way to quantify LAI over large areas. Tremendous efforts have been devoted to this task by remote sensing scientists, but there is still a lack of concensus on how LAI can be best retrieved. Though global LAI products are available, their accuracy has remained unsatisfactory for regional applications. Previous work has primarily focused on using the spectral information in remotely sensed imagery. In this study, we compared the potential of LAI retrieval from various spectral indices derived from Landsat TM images with retrieval using the spatial information, image texture, derived from the Ikonos images. LAI on the ground was derived from allometry, LAI-2000 and the TRAC device in the Duke Forest area in central North Carolina. Our results show that the commonly used spectral indices, normalized difference vegetation index (NDVI) and simple ratio vegetation index (SRVI) were not the best choice for LAI retrieval. We found that Landsat TM derived Structural Index (SI=TM4/TM5) and normalized difference water index (NDWI), as well as Ikonos image texture are much better alternatives.

  4. Extrapolating From Pits: Quantifying spatial variability of snow for remote sensing calibration/validation (Invited)

    NASA Astrophysics Data System (ADS)

    Marshall, H.; Sturm, M.; Elder, K.; Yueh, S. H.

    2013-12-01

    Calibration and validation of radar remote sensing of snow requires information about bulk snow properties such as depth, density, and SWE. Microwave remote sensing observations are sensitive to these bulk properties, but also to the vertical profile of microstructure, requiring in-situ stratigraphic observations of density, grain size and grain shape. Depth measurements can be performed rapidly without excavation, however detailed vertical snow profile information requires careful observations by an experienced observer, which can only be performed in relatively few locations. We use high resolution ground-based radar to extrapolate snow stratigraphy and SWE from snowpits, quantifying the spatial variability of major layer boundaries which cause significant radar reflections, in addition to high resolution radar estimates of SWE, and relating these to in-situ snowpits. The sub-footprint variability is used to help interpret coincident airborne radar backscatter and other remote sensing observations collected during the ESA/NASA AlpSAR campaign in Austria and Alaska-Canada Campaign in 2013.

  5. Effects of different exercise protocols on ethanol-induced spatial memory impairment in adult male rats.

    PubMed

    Hashemi Nosrat Abadi, T; Vaghef, L; Babri, S; Mahmood-Alilo, M; Beirami, M

    2013-06-01

    Chronic ethanol consumption is often accompanied by numerous cognitive deficits and may lead to long-lasting impairments in spatial learning and memory. The aim of the present study was to evaluate the therapeutic potential of regular treadmill exercise on hippocampal-dependent memory in ethanol-treated rats. Spatial memory was tested in a Morris Water Maze task. Adult male Wistar rats were exposed to ethanol (4 g/kg, 20% v/v for 4 weeks) and effects of three exercise protocols (pre-ethanol, post-ethanol and pre-to-post-ethanol treatment) were examined. Results showed that ethanol exposure resulted in longer escape latencies during the acquisition phase of the Morris Water Maze task. Moreover, all three exercise protocols significantly decreased the latency to locate the hidden platform. During the probe trial, ethanol led to decreased time spent in the target quadrant. In contrast, performance on the probe trial was significantly better in the rats that had done the post- and pre-to-post-ethanol, but not pre-ethanol, exercises. These findings suggest that treadmill running can attenuate the adverse effects of chronic ethanol exposure on spatial memory, and may serve as a non-pharmacological alcohol abuse treatment. PMID:23683528

  6. Impaired spatial working memory after anterior thalamic lesions: recovery with cerebrolysin and enrichment.

    PubMed

    Loukavenko, Elena A; Wolff, Mathieu; Poirier, Guillaume L; Dalrymple-Alford, John C

    2016-05-01

    Lesions to the anterior thalamic nuclei (ATN) in rats produce robust spatial memory deficits that reflect their influence as part of an extended hippocampal system. Recovery of spatial working memory after ATN lesions was examined using a 30-day administration of the neurotrophin cerebrolysin and/or an enriched housing environment. As expected, ATN lesions in standard-housed rats given saline produced severely impaired reinforced spatial alternation when compared to standard-housed rats with sham lesions. Both cerebrolysin and enrichment substantially improved this working memory deficit, including accuracy on trials that required attention to distal cues for successful performance. The combination of cerebrolysin and enrichment was more effective than either treatment alone when the delay between successive runs in a trial was increased to 40 s. Compared to the intact rats, ATN lesions in standard-housed groups produced substantial reduction in c-Fos expression in the retrosplenial cortex, which remained low after cerebrolysin and enrichment treatments. Evidence that multiple treatment strategies restore some memory functions in the current lesion model reinforces the prospect for treatments in human diencephalic amnesia. PMID:25725627

  7. The effect of TOMM40 on spatial navigation in amnestic mild cognitive impairment.

    PubMed

    Laczó, Jan; Andel, Ross; Vyhnalek, Martin; Matoska, Vaclav; Kaplan, Vojtech; Nedelska, Zuzana; Lerch, Ondrej; Gazova, Ivana; Moffat, Scott D; Hort, Jakub

    2015-06-01

    The very long (VL) poly-T variant at rs10524523 ("523") of the TOMM40 gene may hasten the onset of late-onset Alzheimer's disease (LOAD) and induce more profound cognitive impairment compared with the short (S) poly-T variant. We examined the influence of TOMM40 "523" polymorphism on spatial navigation and its brain structural correlates. Participants were apolipoprotein E (APOE) ε3/ε3 homozygotes with amnestic mild cognitive impairment (aMCI). The homozygotes were chosen because APOE ε3/ε3 variant is considered "neutral" with respect to LOAD risk. The participants were stratified according to poly-T length polymorphisms at "523" into homozygous for S (S/S; n = 16), homozygous for VL (VL/VL; n = 15) TOMM40 poly-T variant, and heterozygous (S/VL; n = 28) groups. Neuropsychological examination and testing in real-space human analog of the Morris Water Maze were administered. Both self-centered (egocentric) and world-centered (allocentric) spatial navigation was assessed. Brain magnetic resonance imaging scans were analyzed using FreeSurfer software. The S/S group, although similar to S/VL and VL/VL groups in demographic and neuropsychological profiles, performed better on allocentric navigation (p ≤ 0.004) and allocentric delayed recall (p ≤ 0.014), but not on egocentric navigation. Both S/VL and VL/VL groups had thinner right entorhinal cortex (p ≤ 0.043) than the S/S group, whereas only the VL/VL group had thinner left entorhinal cortex (p = 0.043) and left posterior cingulate cortex (p = 0.024) than the S/S group. In conclusion, TOMM40 "523" VL variants are related to impairment in allocentric spatial navigation and reduced cortical thickness of specific brain regions among aMCI individuals with (LOAD neutral) APOE ε3/ε3 genotype. This may reflect a specific role of TOMM40 "523" in the pathogenesis of LOAD. PMID:25862420

  8. Docosahexaenoic acid intake ameliorates ketamine-induced impairment of spatial cognition and learning ability in ICR mice.

    PubMed

    Huang, Shucai; Dai, Yuanyuan; Zhang, Zhiwen; Hao, Wei; Chen, Hongxian

    2014-09-19

    Several studies have reported the ketamine-induced cognitive impairment. Docosahexaenoic acid (DHA) supplementation improves cognitive function in human infants and protects against learning impairment in patients with Alzheimer's disease (AD). In this study, we investigated the effect of DHA on ketamine-induced impairment of spatial cognition and learning ability in Institute of Cancer Research (ICR) mice. Morris water maze (MWM) was used to assess spatial learning and memory. Gamma-aminobutyric acid (GABA) levels in the hippocampus and prefrontal cortex were measured using high-performance liquid chromatography (HPLC). The results showed that intraperitoneal injection of ketamine (30mg/kg, twice per day) for 4 weeks led to the decline of spatial cognitive ability in mice, and 420mg/(kgd) DHA supplementation for 6 weeks improved ketamine-induced spatial cognitive impairment to a certain extent. The up-regulation of GABA levels in the hippocampus and prefrontal cortex was related to the improvement in spatial learning. Our results suggested that DHA supplementation would be a promising intervention to improve ketamine-induced spatial memory and cognitive dysfunction, and this effect of DHA might be correlated with the up-regulation of GABA levels. PMID:25123439

  9. Remote high-definition rotating video enables fast spatial survey of marine underwater macrofauna and habitats.

    PubMed

    Pelletier, Dominique; Leleu, Kévin; Mallet, Delphine; Mou-Tham, Gérard; Hervé, Gilles; Boureau, Matthieu; Guilpart, Nicolas

    2012-01-01

    Observing spatial and temporal variations of marine biodiversity from non-destructive techniques is central for understanding ecosystem resilience, and for monitoring and assessing conservation strategies, e.g. Marine Protected Areas. Observations are generally obtained through Underwater Visual Censuses (UVC) conducted by divers. The problems inherent to the presence of divers have been discussed in several papers. Video techniques are increasingly used for observing underwater macrofauna and habitat. Most video techniques that do not need the presence of a diver use baited remote systems. In this paper, we present an original video technique which relies on a remote unbaited rotating remote system including a high definition camera. The system is set on the sea floor to record images. These are then analysed at the office to quantify biotic and abiotic sea bottom cover, and to identify and count fish species and other species like marine turtles. The technique was extensively tested in a highly diversified coral reef ecosystem in the South Lagoon of New Caledonia, based on a protocol covering both protected and unprotected areas in major lagoon habitats. The technique enabled to detect and identify a large number of species, and in particular fished species, which were not disturbed by the system. Habitat could easily be investigated through the images. A large number of observations could be carried out per day at sea. This study showed the strong potential of this non obtrusive technique for observing both macrofauna and habitat. It offers a unique spatial coverage and can be implemented at sea at a reasonable cost by non-expert staff. As such, this technique is particularly interesting for investigating and monitoring coastal biodiversity in the light of current conservation challenges and increasing monitoring needs. PMID:22383965

  10. Topographic amnesia: spatial memory disorder, perceptual dysfunction, or category specific semantic memory impairment?

    PubMed Central

    McCarthy, R A; Evans, J J; Hodges, J R

    1996-01-01

    A 60 year old patient, SE, who presented with a severe difficulty in finding his way around previously familiar environments and a mild prosopagnosia is described. SE had herpes simplex encephalitis resulting in selective right temporal lobe damage. He showed normal spatial learning, but was severely imparied in his ability to recognise pictures of buildings and landmarks. The disorder was not confined to the visual modality, but rather involved a loss of knowledge about famous buildings and landmarks when tested from their spoken name. SE was contrasted with a more severely prosopagnosic patient, PHD, who showed normal ability to recognise buildings and landmarks, indicating that recognition of people dissociates from recognition of buildings/landmarks. It is concluded that SE's failure of place knowledge represents a category specific supramodal semantic memory impairment. Images PMID:8609511

  11. Spatial cognition and sexually dimorphic synaptic plasticity balance impairment in rats with chronic prenatal ethanol exposure.

    PubMed

    An, Lei; Zhang, Tao

    2013-11-01

    Prenatal ethanol exposure can lead to long-lasting impairments in the ability of rats to process spatial information, as well as produce long-lasting deficits in long-term potentiation (LTP), a biological model of learning and memory processing. The present study aimed to examine the sexually dimorphic effects of chronic prenatal ethanol exposure (CPEE) on behavior cognition and synaptic plasticity balance (SPB), and tried to understand a possible mechanism by evaluating the alternation of SPB. The animal model was produced by ethanol exposure throughout gestational period with 4 g/kg bodyweight. Offspring of both male and female were selected and studied on postnatal days 36. Subsequently, the data showed that chronic ethanol exposure resulted in birth weight reduction, losing bodyweight gain, microcephaly and hippocampus weight retardation. In Morris water maze (MWM) test, escape latencies were significantly higher in CPEE-treated rats than that in control ones. They also spent much less time in the target quadrant compared to that of control animals in the probe phase. In addition, it was found that there was a more severe impairment in females than that in males after CPEE treatment. Electrophysiological studies showed that CPEE considerably inhibited hippocampal LTP and facilitated depotentiation in males, while significantly enhanced LTP and suppressed depotentiation in females. A novel index, developed by us, showed that the action of CPEE on SPB was more sensitive in females than that in males, suggesting that it might be an effective index to distinguish the difference of SPB impairment between males and females. PMID:24050890

  12. Characterization of Forested Landscapes From Remotely Sensed Data Using Fractals and Spatial Autocorrelation

    NASA Technical Reports Server (NTRS)

    Al-Hamdan, Mohammad Z.; Cruise, James F.; Rickman, Douglas L.; Quattrochi, Dale A.

    2007-01-01

    The characterization of forested areas is frequently required in resource management practice. Passive remotely sensed data, which are much more accessible and cost effective than are active data, have rarely, if ever, been used to characterize forest structure directly, but rather they usually focus on the estimation of indirect measurement of biomass or canopy coverage. In this study, some spatial analysis techniques are presented that might be employed with Landsat TM data to analyze forest structure characteristics. A case study is presented wherein fractal dimensions, along with a simple spatial autocorrelation technique (Moran s I), were related to stand density parameters of the Oakmulgee National Forest located in the southeastern United States (Alabama). The results of the case study presented herein have shown that as the percentage of smaller diameter trees becomes greater, and particularly if it exceeds 50%, then the canopy image obtained from Landsat TM data becomes sufficiently homogeneous so that the spatial indices reach their lower limits and thus are no longer determinative. It also appears, at least for the Oakmulgee forest, that the relationships between the spatial indices and forest class percentages within the boundaries can reasonably be considered linear. The linear relationship is much more pronounced in the sawtimber and saplings cases than in samples dominated by medium sized trees (poletimber). In addition, it also appears that, at least for the Oakmulgee forest, the relationships between the spatial indices and forest species groups (Hardwood and Softwood) percentages can reasonably be considered linear. The linear relationship is more pronounced in the forest species groups cases than in the forest classes cases. These results appear to indicate that both fractal dimensions and spatial autocorrelation indices hold promise as means of estimating forest stand characteristics from remotely sensed images. However, additional work is

  13. Excitotoxic lesion of the perirhinal cortex impairs spatial working memory in a delayed-alternation task.

    PubMed

    Maioli, Silvia; Gangarossa, Giuseppe; Locchi, Federica; Andrioli, Anna; Bertini, Giuseppe; Rimondini, Roberto

    2012-05-01

    The perirhinal cortex (PRh) is strategically located between the neocortex and memory-related structures such as the entorhinal cortex and the hippocampal formation. The pattern of strong reciprocal connections between these areas, together with experimental evidence that PRh damage induces specific memory deficits, has placed this cortical region at the center of a growing interest for its role in learning and memory mechanisms. The aim of the present study is to clarify the involvement of PRh in learning and retention in a novel experimental model of spatial working memory, the water T-maze. The data show that pre-acquisition neurotoxic PRh lesions caused task-learning deficits. This impairment was observed during the acquisition phase as well as the retrieval phase. On the other hand, a post-acquisition PRh neurotoxic lesion failed to impair the acquisition and the retrieval of the water T-maze task performed 32 day after lesion. These results suggest a possible key role of PRh in the acquisition but not in the retention of a working memory task. Furthermore, these results show that the water T-maze may be a suitable learning paradigm to study different components of learning and memory. PMID:22391121

  14. Dimethyl fumarate attenuates intracerebroventricular streptozotocin-induced spatial memory impairment and hippocampal neurodegeneration in rats.

    PubMed

    Majkutewicz, Irena; Kurowska, Ewelina; Podlacha, Magdalena; Myślińska, Dorota; Grembecka, Beata; Ruciński, Jan; Plucińska, Karolina; Jerzemowska, Grażyna; Wrona, Danuta

    2016-07-15

    Intracerebroventricular (ICV) injection of streptozotocin (STZ) is a widely-accepted animal model of sporadic Alzheimer's disease (sAD). The present study evaluated the ability of dimethyl fumarate (DMF), an agent with antioxidant and anti-inflammatory properties, to prevent spatial memory impairments and hippocampal neurodegeneration mediated by ICV injection of STZ in 4-month-old rats. Rodent chow containing DMF (0.4%) or standard rodent chow was made available on day 0. Rat body weight and food intake were measured daily for whole the experiment (21days). STZ or vehicle (SHAM) ICV injections were performed on days 2 and 4. Spatial reference and working memory were evaluated using the Morris water maze on days 14-21. Cells containing Fluoro-Jade B (neurodegeneration marker), IL-6, IL-10 were quantified in the hippocampus and choline acetyltransferase (ChAT) in the basal forebrain. The disruption of spatial memory and a high density of hippocampal CA1-3 cells labeled with Fluoro-Jade B or containing IL-6 or IL-10 were observed in the STZ group but not in the STZ+DMF group, as compared to the SHAM or SHAM+DMF groups. STZ vs. STZ+DMF differences were found: worse reference memory acquisition, fewer ChAT-positive neurons in the medial septum (Ch1), more Fluoro-Jade-positive CA1 hippocampal cells in STZ rats. DMF therapy in a rodent model of sAD prevented the disruption of spatial reference and working memory, loss of Ch1 cholinergic cells and hippocampal neurodegeneration as well as the induction of IL-6 and IL-10 in CA1. These beneficial cognitive and molecular effects validate the anti-inflammatory and neuroprotective properties of DMF in the hippocampus. PMID:27083302

  15. Mesoscale spatial variability of selected aquatic invertebrate community metrics from a minimally impaired stream segment

    USGS Publications Warehouse

    Gebler, J.B.

    2004-01-01

    The related topics of spatial variability of aquatic invertebrate community metrics, implications of spatial patterns of metric values to distributions of aquatic invertebrate communities, and ramifications of natural variability to the detection of human perturbations were investigated. Four metrics commonly used for stream assessment were computed for 9 stream reaches within a fairly homogeneous, minimally impaired stream segment of the San Pedro River, Arizona. Metric variability was assessed for differing sampling scenarios using simple permutation procedures. Spatial patterns of metric values suggest that aquatic invertebrate communities are patchily distributed on subsegment and segment scales, which causes metric variability. Wide ranges of metric values resulted in wide ranges of metric coefficients of variation (CVs) and minimum detectable differences (MDDs), and both CVs and MDDs often increased as sample size (number of reaches) increased, suggesting that any particular set of sampling reaches could yield misleading estimates of population parameters and effects that can be detected. Mean metric variabilities were substantial, with the result that only fairly large differences in metrics would be declared significant at ?? = 0.05 and ?? = 0.20. The number of reaches required to obtain MDDs of 10% and 20% varied with significance level and power, and differed for different metrics, but were generally large, ranging into tens and hundreds of reaches. Study results suggest that metric values from one or a small number of stream reach(es) may not be adequate to represent a stream segment, depending on effect sizes of interest, and that larger sample sizes are necessary to obtain reasonable estimates of metrics and sample statistics. For bioassessment to progress, spatial variability may need to be investigated in many systems and should be considered when designing studies and interpreting data.

  16. Humanin Does Not Protect Against STZ-Induced Spatial Memory Impairment.

    PubMed

    Negintaji, Kourosh; Zarifkar, Asadollah; Ghasemi, Rasoul; Moosavi, Maryam

    2015-06-01

    [Gly14]-Humanin (HNG) is a 24-amino acid peptide which was first identified in the brains of patients diagnosed with Alzheimer's disease (AD). In this region, some neurons were protected against cell damage occurring in this disease. Further studies suggested a neuroprotective role for humanin against Aβ and some other insults. Intraventricularly administered streptozotocin (STZ) disrupts insulin signaling pathway which leads to behavioral and biochemical changes resemble to early signs of AD; therefore, STZ model has been proposed as a model for sporadic Alzheimer's disease (sAD). Regarding the reported beneficial effects of humanin in AD, this study was aimed to investigate if this peptide prevents spatial memory and hippocampal PI3/Akt signaling impairment induced by centrally injected STZ. Adult male Sprague-Dawely rats weighting 250-300 g were used, and cannuls were implanted bilaterally into lateral ventricles. STZ was administered on days 1 and 3 (3 mg/kg), and humanin (0.01, 0.05, 0.1, and 1 nmol) or saline were injected from day 4 and continued till day 14. The animal's learning and memory capability was assessed on days 15-18 using Morris water maze. After complement of behavioral studies, the hippocampi were isolated, and the level of phosphorylated Akt (pAkt) was assessed through Western blot analysis. The results showed that STZ significantly impaired spatial memory, and humanin in a wide range of doses (0.01, 0.05, 0.1, and 1 nmol) failed to restore STZ-induced deficit. It was also revealed that humanin was not efficient in restoring pAkt disruption. It seems that humanin is not capable in restoring memory deterioration that resulted from insulin signaling disruption. PMID:25744099

  17. Increased anxiety and impaired spatial memory in young adult rats following adolescent exposure to methylone.

    PubMed

    Daniel, Jollee J; Hughes, Robert N

    2016-01-01

    This study investigated the possibility that treatment of adolescent rats with the substituted cathinone, 3,4-methylenedioxymethcathinone (methylone), might result in heightened anxiety and/or impaired memory during early adulthood, as has been shown for other designer drugs. For 10 consecutive days from 35days after birth (PND35-44, early adolescence) or 45days after birth (PND45-54, late adolescence), male and female PVG/c rats were administered saline or 8.0mg/kg methylone via intraperitoneal injection. When 90days old (early adulthood), their anxiety-related behavior was recorded in an open field and a light/dark box. Acoustic startle amplitude was also measured as well as their spatial memory which was determined by their ability to detect which arm of a Y maze had changed in brightness between an acquisition and a retention trial. Previously methylone-treated rats showed increased anxiety-related behavior only in the open field as reflected in decreased ambulation, and increased corner occupancy and defecation. In the latter two cases, the increases depended on the age of treatment. Also, for defecation, only male rats were affected. In addition, methylone-treated rats displayed signs of impaired spatial memory, independent of anxiety, through their reduced ability to detect a novel changed Y-maze arm. The results of the study suggested some possible consequences in adulthood of methylone use during adolescence. There were also several examples of female rats exhibiting higher overall frequencies of activity and anxiety-related responding than males that were consistent with them being the more active and less anxious of the two sexes. PMID:27178814

  18. Winter wheat growth spatial variation monitoring through hyperspectral remote sensing image

    NASA Astrophysics Data System (ADS)

    Song, Xiaoyu; Li, Ting; Wang, Jihua; Gu, Xiaohe; Xu, Xingang

    2015-10-01

    This work aims at quantifying the winter wheat growth spatial heterogeneity captured by hyperspectral airborne images. The field experiment was conducted in 2001 and 2002 and airborne hyperspectral remote-sensing data was acquired at noon on 11 April 2001 using an operational modular imaging spectrometer (OMIS). Totally 12 winter fields which covered by both dense and sparse winter wheat canopies were selected to analysis the winter wheat growth heterogeneity. The experimental semi-variograms for bands covered from invisible to mid-infrared were computed for each field then the theoretical models were be fitted with least squares algorithm for spherical model, exponential model. The optimization model was selected after evaluated by R-square. Three key terms in each model, the sill, the range, and nugget variance were then calculated from the models. The study results show that the sill, range and nugget for same field wheat were varied with the wavelength from blue to mid infrared bands. Although wheat growth in different fields showed different spatial heterogeneity, they all showed an obvious sill pattern. The minimum of mean range value was 7.52 m for mid-infrared bands while the maximum value was 91.71 m for visible bands. The minimum of mean sill value ranged from 1.46 for visible bands to 39.76 for NIR bands, the minimum of mean nugget value ranged from 0.06 for visible bands to5.45 for mid-infrared bands. This study indicate that remote sensing image is important for crop growth spatial heterogeneity study. But it is necessary to explore the effect of different wavelength of image data on crop growth semi-variogram estimation and find out which band data could be used to estimate crop semi-variogram reliably.

  19. Spatially Explicit Forest Characteristics of Europe Integrating NFI and Remote Sensing Data

    NASA Astrophysics Data System (ADS)

    Moreno, A. L. S.; Neumann, M.; Hasenauer, H.

    2015-12-01

    Seeing the forest through the trees in Europe is easier said than done. European forest data is nationally collected using different methodologies and sampling techniques. This data can be difficult to obtain, and if made available often lacks spatial information and might only be provided in the local language. This makes analyzing forests in Europe difficult. The reporting systems of Food and Agriculture Organization (FAO) and the European Forestry Institute (EFI) permit several acquisition and calculation methodologies which lead to difficulties in comparing country level data. We have collected spatially explicit national forest inventory (NFI) data from 13 countries in Europe and harmonized these datasets. Using this data along with remote sensing data products we have derived spatially explicit forest characteristics maps of Europe on a 0.017o resolution representing the time period 2000-2010. We have created maps for every NFI variable in our dataset including carbon stock, forest age, forest height, volume, basal area, etc. Cross-validating this data shows that this method produces accurate results for most variables while variables pertaining to forest cover type have lower accuracy. This data is in line with data from FAO and EFI in most cases. However, our dataset allows us to identify large incongruities quickly in FAO and EFI data. Our spatially explicit data is also accurate at predicting forest characteristics in areas where we have no NFI data. This data set provides a consistent harmonized view of the state of European forests in a way hitherto not possible, giving researchers the ability to analyze forests spatially across the entire continent. This method can also be useful for those researching areas that have little or no NFI data or areas where data acquisition is difficult or impossible. This data can also quickly give policy makers a greater view of how forest management practices have shaped our current European forests.

  20. Spatial information technologies for remote sensing today and tomorrow; Proceedings of the Ninth Pecora Symposium, Sioux Falls, SD, October 2-4, 1984

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Topics discussed at the symposium include hardware, geographic information system (GIS) implementation, processing remotely sensed data, spatial data structures, and NASA programs in remote sensing information systems. Attention is also given GIS applications, advanced techniques, artificial intelligence, graphics, spatial navigation, and classification. Papers are included on the design of computer software for geographic image processing, concepts for a global resource information system, algorithm development for spatial operators, and an application of expert systems technology to remotely sensed image analysis.

  1. Use of a modified spatial-context memory test to detect amnestic mild cognitive impairment.

    PubMed

    Wang, Hsuan-Min; Yang, Chien-Ming; Kuo, Wan-Chin; Huang, Chin-Chang; Kuo, Hung-Chou

    2013-01-01

    In this study we sought to differentiate participants with amnestic mild cognitive impairment (a-MCI) from those with mild dementia of Alzheimer's type (m-DAT) and normal controls by modifying an existing test of spatial context memory (SCMT) designed so as to evaluate the function of brain regions affected in early m-DAT. We found that participants with a-MCI had better total scores on our modified SCMT than those with m-DAT. Furthermore, the locational memory subtest was able to discriminate between those with a-MCI and m-DAT. Additionally, compared with other screening tests, our spatial context memory test showed high sensitivity and specificity in discerning those with a-MCI from the normal population but, was relatively ineffective in discriminating a-MCI patients from those with m-DAT. We conclude that our modified test of SCMT is an effective tool for discriminating a-MCI from m-DAT and does so by detecting differences in locational memory. PMID:23468906

  2. SEIZURES IN EARLY-LIFE SUPPRESS HIPPOCAMPAL DENDRITE GROWTH WHILE IMPAIRING SPATIAL LEARNING

    PubMed Central

    Nishimura, Masataka; Gu, Xue; Swann, John W.

    2011-01-01

    Impaired learning and memory are common in epilepsy syndromes of childhood. Clinical investigations suggest that the developing brain may be particularly vulnerable to the effects of intractable seizure disorders. Magnetic resonance imaging (MRI) studies have demonstrated reduced volumes in brain regions involved in learning and memory. The earlier the onset of an epilepsy the larger the effects seem to be on both brain anatomy and cognition. Thus, childhood epilepsy has been proposed to interfere in some unknown way with brain development. Experiments reported here explore these ideas by examining the effects of seizures in infant mice on learning and memory and on the growth of CA1 hippocampal pyramidal cell dendrites. Fifteen brief seizures were induced by flurothyl between postnatal days 7 and 11 in mice that express green fluorescent protein (GFP) in hippocampal pyramidal cells. One to 44 days later, dendritic arbors were reconstructed to measure growth. Spatial learning and memory were also assessed in a water maze. Our results show that recurrent seizures produced marked deficits in learning and memory. Seizures also dramatically slowed the growth of basilar dendrites while neurons in litter-mate control mice continued to add new dendritic branches and lengthen existing branches. When experiments were performed in older mice, seizures had no measureable effects on either dendrite arbor complexity or spatial learning and memory. Our results suggest that the recurring seizures of intractable childhood epilepsy contribute to associated learning and memory deficits by suppressing dendrite growth. PMID:21777677

  3. Disrupting Jagged1-Notch signaling impairs spatial memory formation in adult mice.

    PubMed

    Sargin, Derya; Botly, Leigh C P; Higgs, Gemma; Marsolais, Alexander; Frankland, Paul W; Egan, Sean E; Josselyn, Sheena A

    2013-07-01

    It is well-known that Notch signaling plays a critical role in brain development and growing evidence implicates this signaling pathway in adult synaptic plasticity and memory formation. The Notch1 receptor is activated by two subclasses of ligands, Delta-like (including Dll1 and Dll4) and Jagged (including Jag1 and Jag2). Ligand-induced Notch1 receptor signaling is modulated by a family of Fringe proteins, including Lunatic fringe (Lfng). Although Dll1, Jag1 and Lfng are critical regulators of Notch signaling, their relative contribution to memory formation in the adult brain is unknown. To investigate the roles of these important components of Notch signaling in memory formation, we examined spatial and fear memory formation in adult mice with reduced expression of Dll1, Jag1, Lfng and Dll1 plus Lfng. We also examined motor activity, anxiety-like behavior and sensorimotor gating using the acoustic startle response in these mice. Of the lines of mutant mice tested, we found that only mice with reduced Jag1 expression (mice heterozygous for a null mutation in Jag1, Jag1(+/-)) showed a selective impairment in spatial memory formation. Importantly, all other behavior including open field activity, conditioned fear memory (both context and discrete cue), acoustic startle response and prepulse inhibition, was normal in this line of mice. These results provide the first in vivo evidence that Jag1-Notch signaling is critical for memory formation in the adult brain. PMID:23567106

  4. Reprint of: disrupting Jagged1-Notch signaling impairs spatial memory formation in adult mice.

    PubMed

    Sargin, Derya; Botly, Leigh C P; Higgs, Gemma; Marsolais, Alexander; Frankland, Paul W; Egan, Sean E; Josselyn, Sheena A

    2013-10-01

    It is well-known that Notch signaling plays a critical role in brain development and growing evidence implicates this signaling pathway in adult synaptic plasticity and memory formation. The Notch1 receptor is activated by two subclasses of ligands, Delta-like (including Dll1 and Dll4) and Jagged (including Jag1 and Jag2). Ligand-induced Notch1 receptor signaling is modulated by a family of Fringe proteins, including Lunatic fringe (Lfng). Although Dll1, Jag1 and Lfng are critical regulators of Notch signaling, their relative contribution to memory formation in the adult brain is unknown. To investigate the roles of these important components of Notch signaling in memory formation, we examined spatial and fear memory formation in adult mice with reduced expression of Dll1, Jag1, Lfng and Dll1 plus Lfng. We also examined motor activity, anxiety-like behavior and sensorimotor gating using the acoustic startle response in these mice. Of the lines of mutant mice tested, we found that only mice with reduced Jag1 expression (mice heterozygous for a null mutation in Jag1, Jag1(+/-)) showed a selective impairment in spatial memory formation. Importantly, all other behavior including open field activity, conditioned fear memory (both context and discrete cue), acoustic startle response and prepulse inhibition, was normal in this line of mice. These results provide the first in vivo evidence that Jag1-Notch signaling is critical for memory formation in the adult brain. PMID:23850596

  5. Astaxanthin ameliorates aluminum chloride-induced spatial memory impairment and neuronal oxidative stress in mice.

    PubMed

    Al-Amin, Md Mamun; Reza, Hasan Mahmud; Saadi, Hasan Mahmud; Mahmud, Waich; Ibrahim, Abdirahman Adam; Alam, Musrura Mefta; Kabir, Nadia; Saifullah, A R M; Tropa, Sarjana Tarannum; Quddus, A H M Ruhul

    2016-04-15

    Aluminum chloride induces neurodegenerative disease in animal model. Evidence suggests that aluminum intake results in the activation of glial cells and generation of reactive oxygen species. By contrast, astaxanthin is an antioxidant having potential neuroprotective activity. In this study, we investigate the effect of astaxanthin on aluminum chloride-exposed behavioral brain function and neuronal oxidative stress (OS). Male Swiss albino mice (4 months old) were divided into 4 groups: (i) control (distilled water), (ii) aluminum chloride, (iii) astaxanthin+aluminum chloride, and (iv) astaxanthin. Two behavioral tests; radial arm maze and open field test were conducted, and OS markers were assayed from the brain and liver tissues following 42 days of treatment. Aluminum exposed group showed a significant reduction in spatial memory performance and anxiety-like behavior. Moreover, aluminum group exhibited a marked deterioration of oxidative markers; lipid peroxidation (MDA), nitric oxide (NO), glutathione (GSH) and advanced oxidation of protein products (AOPP) in the brain. To the contrary, co-administration of astaxanthin and aluminum has shown improved spatial memory, locomotor activity, and OS. These results indicate that astaxanthin improves aluminum-induced impaired memory performances presumably by the reduction of OS in the distinct brain regions. We suggest a future study to determine the underlying mechanism of astaxanthin in improving aluminum-exposed behavioral deficits. PMID:26927754

  6. Hippocampal inactivation with TTX impairs long-term spatial memory retrieval and modifies brain metabolic activity.

    PubMed

    Conejo, Nélida María; Cimadevilla, José Manuel; González-Pardo, Héctor; Méndez-Couz, Marta; Arias, Jorge Luis

    2013-01-01

    Functional inactivation techniques enable studying the hippocampal involvement in each phase of spatial memory formation in the rat. In this study, we applied tetrodotoxin unilaterally or bilaterally into the dorsal hippocampus to evaluate the role of this brain structure in retrieval of memories acquired 28 days before in the Morris water maze. We combined hippocampal inactivation with the assessment of brain metabolism using cytochrome oxidase histochemistry. Several brain regions were considered, including the hippocampus and other related structures. Results showed that both unilateral and bilateral hippocampal inactivation impaired spatial memory retrieval. Hence, whereas subjects with bilateral hippocampal inactivation showed a circular swim pattern at the side walls of the pool, unilateral inactivation favoured swimming in the quadrants adjacent to the target one. Analysis of cytochrome oxidase activity disclosed regional differences according to the degree of hippocampal functional blockade. In comparison to control group, animals with bilateral inactivation showed increased CO activity in CA1 and CA3 areas of the hippocampus during retrieval, while the activity of the dentate gyrus substantially decreased. However, unilateral inactivated animals showed decreased CO activity in Ammon's horn and the dentate gyrus. This study demonstrated that retrieval recruits differentially the hippocampal subregions and the balance between them is altered with hippocampal functional lesions. PMID:23724089

  7. Hippocampal Inactivation with TTX Impairs Long-Term Spatial Memory Retrieval and Modifies Brain Metabolic Activity

    PubMed Central

    Conejo, Nélida María; Cimadevilla, José Manuel; González-Pardo, Héctor; Méndez-Couz, Marta; Arias, Jorge Luis

    2013-01-01

    Functional inactivation techniques enable studying the hippocampal involvement in each phase of spatial memory formation in the rat. In this study, we applied tetrodotoxin unilaterally or bilaterally into the dorsal hippocampus to evaluate the role of this brain structure in retrieval of memories acquired 28 days before in the Morris water maze. We combined hippocampal inactivation with the assessment of brain metabolism using cytochrome oxidase histochemistry. Several brain regions were considered, including the hippocampus and other related structures. Results showed that both unilateral and bilateral hippocampal inactivation impaired spatial memory retrieval. Hence, whereas subjects with bilateral hippocampal inactivation showed a circular swim pattern at the side walls of the pool, unilateral inactivation favoured swimming in the quadrants adjacent to the target one. Analysis of cytochrome oxidase activity disclosed regional differences according to the degree of hippocampal functional blockade. In comparison to control group, animals with bilateral inactivation showed increased CO activity in CA1 and CA3 areas of the hippocampus during retrieval, while the activity of the dentate gyrus substantially decreased. However, unilateral inactivated animals showed decreased CO activity in Ammon's horn and the dentate gyrus. This study demonstrated that retrieval recruits differentially the hippocampal subregions and the balance between them is altered with hippocampal functional lesions. PMID:23724089

  8. Analysing and correcting the differences between multi-source and multi-scale spatial remote sensing observations.

    PubMed

    Dong, Yingying; Luo, Ruisen; Feng, Haikuan; Wang, Jihua; Zhao, Jinling; Zhu, Yining; Yang, Guijun

    2014-01-01

    Differences exist among analysis results of agriculture monitoring and crop production based on remote sensing observations, which are obtained at different spatial scales from multiple remote sensors in same time period, and processed by same algorithms, models or methods. These differences can be mainly quantitatively described from three aspects, i.e. multiple remote sensing observations, crop parameters estimation models, and spatial scale effects of surface parameters. Our research proposed a new method to analyse and correct the differences between multi-source and multi-scale spatial remote sensing surface reflectance datasets, aiming to provide references for further studies in agricultural application with multiple remotely sensed observations from different sources. The new method was constructed on the basis of physical and mathematical properties of multi-source and multi-scale reflectance datasets. Theories of statistics were involved to extract statistical characteristics of multiple surface reflectance datasets, and further quantitatively analyse spatial variations of these characteristics at multiple spatial scales. Then, taking the surface reflectance at small spatial scale as the baseline data, theories of Gaussian distribution were selected for multiple surface reflectance datasets correction based on the above obtained physical characteristics and mathematical distribution properties, and their spatial variations. This proposed method was verified by two sets of multiple satellite images, which were obtained in two experimental fields located in Inner Mongolia and Beijing, China with different degrees of homogeneity of underlying surfaces. Experimental results indicate that differences of surface reflectance datasets at multiple spatial scales could be effectively corrected over non-homogeneous underlying surfaces, which provide database for further multi-source and multi-scale crop growth monitoring and yield prediction, and their corresponding

  9. Analysing and Correcting the Differences between Multi-Source and Multi-Scale Spatial Remote Sensing Observations

    PubMed Central

    Dong, Yingying; Luo, Ruisen; Feng, Haikuan; Wang, Jihua; Zhao, Jinling; Zhu, Yining; Yang, Guijun

    2014-01-01

    Differences exist among analysis results of agriculture monitoring and crop production based on remote sensing observations, which are obtained at different spatial scales from multiple remote sensors in same time period, and processed by same algorithms, models or methods. These differences can be mainly quantitatively described from three aspects, i.e. multiple remote sensing observations, crop parameters estimation models, and spatial scale effects of surface parameters. Our research proposed a new method to analyse and correct the differences between multi-source and multi-scale spatial remote sensing surface reflectance datasets, aiming to provide references for further studies in agricultural application with multiple remotely sensed observations from different sources. The new method was constructed on the basis of physical and mathematical properties of multi-source and multi-scale reflectance datasets. Theories of statistics were involved to extract statistical characteristics of multiple surface reflectance datasets, and further quantitatively analyse spatial variations of these characteristics at multiple spatial scales. Then, taking the surface reflectance at small spatial scale as the baseline data, theories of Gaussian distribution were selected for multiple surface reflectance datasets correction based on the above obtained physical characteristics and mathematical distribution properties, and their spatial variations. This proposed method was verified by two sets of multiple satellite images, which were obtained in two experimental fields located in Inner Mongolia and Beijing, China with different degrees of homogeneity of underlying surfaces. Experimental results indicate that differences of surface reflectance datasets at multiple spatial scales could be effectively corrected over non-homogeneous underlying surfaces, which provide database for further multi-source and multi-scale crop growth monitoring and yield prediction, and their corresponding

  10. Spatial and Temporal Dust Source Variability in Northern China Identified Using Advanced Remote Sensing Analysis

    NASA Technical Reports Server (NTRS)

    Taramelli, A.; Pasqui, M.; Barbour, J.; Kirschbaum, D.; Bottai, L.; Busillo, C.; Calastrini, F.; Guarnieri, F.; Small, C.

    2013-01-01

    The aim of this research is to provide a detailed characterization of spatial patterns and temporal trends in the regional and local dust source areas within the desert of the Alashan Prefecture (Inner Mongolia, China). This problem was approached through multi-scale remote sensing analysis of vegetation changes. The primary requirements for this regional analysis are high spatial and spectral resolution data, accurate spectral calibration and good temporal resolution with a suitable temporal baseline. Landsat analysis and field validation along with the low spatial resolution classifications from MODIS and AVHRR are combined to provide a reliable characterization of the different potential dust-producing sources. The representation of intra-annual and inter-annual Normalized Difference Vegetation Index (NDVI) trend to assess land cover discrimination for mapping potential dust source using MODIS and AVHRR at larger scale is enhanced by Landsat Spectral Mixing Analysis (SMA). The combined methodology is to determine the extent to which Landsat can distinguish important soils types in order to better understand how soil reflectance behaves at seasonal and inter-annual timescales. As a final result mapping soil surface properties using SMA is representative of responses of different land and soil cover previously identified by NDVI trend. The results could be used in dust emission models even if they are not reflecting aggregate formation, soil stability or particle coatings showing to be critical for accurately represent dust source over different regional and local emitting areas.

  11. Rearing without early access to perches impairs the spatial skills of laying hens.

    PubMed

    Gunnarsson; Yngvesson; Keeling; Forkman

    2000-04-01

    The effect of rearing with and without perches on the spatial ability of domestic hens (Gallus gallus domesticus) was investigated. No access or late access to perches during rearing has been shown to increase the later prevalence of floor eggs and cloacal cannibalism in loose-housed laying hens. This may be explained by either the birds reared without perches have difficulty using perches due to low muscle strength, lack of motor skills, and inability to keep balance, or they have impaired spatial skills necessary for moving around in three-dimensional space. These alternative explanations are not mutually exclusive.Thirty, day-old chicks were randomly allocated into two equal groups and reared in litter pens, one with access to perches (P+) and one without (P-). At 8 weeks of age, all birds were given access to perches, and by 15 weeks, all birds were using perches for roosting at night. At 16 weeks, 10 birds from each group were tested in pens where food was presented on a wire mesh tier 40 cm above the ground (T40). Three consecutive tests, with increasing difficulty for the bird to reach the food, were then performed. Firstly, the food was presented at 80 cm above the ground but with the tier at 40 cm still present; secondly, food was presented on the tier at 80 cm; and then, finally, with the food on a 160 cm high tier with the tier at 80 cm still present. All birds were food deprived for 15 h before each test and the time from the bird entering the pen until reaching the food was recorded. There was no difference in the time to reach the food between P+ and P- birds in the T40 test. But as the difficulty of the task increased, the difference between the P+ and P- birds became significant, with the P- birds taking a longer time to reach the food or not reaching it at all. Since there was no difference between P+ and P- in the T40 test, it seems reasonable to suppose that the later differences did not depend on differences in physical ability. Therefore, the

  12. Reversible Hippocampal Lesions Disrupt Water Maze Performance during Both Recent and Remote Memory Tests

    ERIC Educational Resources Information Center

    Broadbent, Nicola J.; Squire, Larry R.; Clark, Robert E.

    2006-01-01

    Conventional lesion methods have shown that damage to the rodent hippocampus can impair previously acquired spatial memory in tasks such as the water maze. In contrast, work with reversible lesion methods using a different spatial task has found remote memory to be spared. To determine whether the finding of spared remote spatial memory depends on…

  13. Assimilation of remote sensing observations into a sediment transport model of China's largest freshwater lake: spatial and temporal effects.

    PubMed

    Zhang, Peng; Chen, Xiaoling; Lu, Jianzhong; Zhang, Wei

    2015-12-01

    Numerical models are important tools that are used in studies of sediment dynamics in inland and coastal waters, and these models can now benefit from the use of integrated remote sensing observations. This study explores a scheme for assimilating remotely sensed suspended sediment (from charge-coupled device (CCD) images obtained from the Huanjing (HJ) satellite) into a two-dimensional sediment transport model of Poyang Lake, the largest freshwater lake in China. Optimal interpolation is used as the assimilation method, and model predictions are obtained by combining four remote sensing images. The parameters for optimal interpolation are determined through a series of assimilation experiments evaluating the sediment predictions based on field measurements. The model with assimilation of remotely sensed sediment reduces the root-mean-square error of the predicted sediment concentrations by 39.4% relative to the model without assimilation, demonstrating the effectiveness of the assimilation scheme. The spatial effect of assimilation is explored by comparing model predictions with remotely sensed sediment, revealing that the model with assimilation generates reasonable spatial distribution patterns of suspended sediment. The temporal effect of assimilation on the model's predictive capabilities varies spatially, with an average temporal effect of approximately 10.8 days. The current velocities which dominate the rate and direction of sediment transport most likely result in spatial differences in the temporal effect of assimilation on model predictions. PMID:26199002

  14. Chronic dietary chlorpyrifos causes long-term spatial memory impairment and thigmotaxic behavior.

    PubMed

    López-Granero, Caridad; Ruiz-Muñoz, Ana M; Nieto-Escámez, Francisco A; Colomina, María T; Aschner, Michael; Sánchez-Santed, Fernando

    2016-03-01

    Little is known about the long-term effects of chronic exposure to low-level organophosphate (OP) pesticides, and the role of neurotransmitter systems, other than the cholinergic system, in mediating OP neurotoxicity. In this study, rats were administered 5mg/kg/day of chlorpyrifos (CPF) for 6 months commencing at 3-months-of-age. The animals were examined 7 months later (at 16-months-of-age) for spatial learning and memory in the Morris water maze (MWM) and locomotor activity. In addition, we assessed the chronic effects of CPF on glutamatergic and gamma-aminobutyric acid (GABAergic) function using pharmacological challenges with dizocilpine (MK801) and diazepam. Impaired performance related to altered search patterns, including thigmotaxis and long-term spatial memory was noted in the MWM in animals exposed to CPF, pointing to dietary CPF-induced behavioral disturbances, such as anxiety. Twenty-four hours after the 31st session of repeated acquisition task, 0.1mg/kg MK801, an N-methyl-d-aspartate (NMDA) antagonist was intraperitoneally (i.p.) injected for 4 consecutive days. Decreased latencies in the MWM in the control group were noted after two sessions with MK801 treatment. Once the MWM assessment was completed, animals were administered 0.1 or 0.2mg/kg of MK801 and 1 or 3mg/kg of diazepam i.p., and tested for locomotor activity. Both groups, the CPF dietary and control, displayed analogous performance in motor activity. In conclusion, our data point to a connection between the long-term spatial memory, thigmotaxic response and CPF long after the exposure ended. PMID:26748072

  15. Auditory Spatial Discrimination and the Mismatch Negativity Response in Hearing-Impaired Individuals

    PubMed Central

    Cai, Yuexin; Zheng, Yiqing; Liang, Maojin; Zhao, Fei; Yu, Guangzheng; Liu, Yu; Chen, Yuebo; Chen, Guisheng

    2015-01-01

    The aims of the present study were to investigate the ability of hearing-impaired (HI) individuals with different binaural hearing conditions to discriminate spatial auditory-sources at the midline and lateral positions, and to explore the possible central processing mechanisms by measuring the minimal audible angle (MAA) and mismatch negativity (MMN) response. To measure MAA at the left/right 0°, 45° and 90° positions, 12 normal-hearing (NH) participants and 36 patients with sensorineural hearing loss, which included 12 patients with symmetrical hearing loss (SHL) and 24 patients with asymmetrical hearing loss (AHL) [12 with unilateral hearing loss on the left (UHLL) and 12 with unilateral hearing loss on the right (UHLR)] were recruited. In addition, 128-electrode electroencephalography was used to record the MMN response in a separate group of 60 patients (20 UHLL, 20 UHLR and 20 SHL patients) and 20 NH participants. The results showed MAA thresholds of the NH participants to be significantly lower than the HI participants. Also, a significantly smaller MAA threshold was obtained at the midline position than at the lateral position in both NH and SHL groups. However, in the AHL group, MAA threshold for the 90° position on the affected side was significantly smaller than the MMA thresholds obtained at other positions. Significantly reduced amplitudes and prolonged latencies of the MMN were found in the HI groups compared to the NH group. In addition, contralateral activation was found in the UHL group for sounds emanating from the 90° position on the affected side and in the NH group. These findings suggest that the abilities of spatial discrimination at the midline and lateral positions vary significantly in different hearing conditions. A reduced MMN amplitude and prolonged latency together with bilaterally symmetrical cortical activations over the auditory hemispheres indicate possible cortical compensatory changes associated with poor behavioral spatial

  16. Prenatal oxycodone exposure impairs spatial learning and/or memory in rats.

    PubMed

    Davis, Chris P; Franklin, La'tonya M; Johnson, Gabriel S; Schrott, Lisa M

    2010-09-01

    Recent changes in demographic patterns of drug use have resulted in the increased non-medical use of prescription opiates. These users are younger and more likely to be female, which has the potential for increasing rates of in utero exposure. Therefore, we developed a rat model that simulates a prescription opiate-dependent woman who becomes pregnant. Adult female Sprague-Dawley rats were treated for 30 days via oral gavage with ascending doses of oxycodone HCl up to a final dose of 15mg/kg/day, which was maintained during breeding and gestation. Controls were treated with water. The adult male offspring of these treated dams were tested on the radial arm maze, the Morris water maze (with a short and a long intertrial interval), and a spatial T-maze. Prenatal oxycodone exposure led to a deficit in the radial arm maze characterized by a greater number of reference memory errors, especially in the beginning of testing. In contrast, in the T-maze, prenatal oxycodone-exposed rats learned the task as well as well as the prenatal water controls. However, they had a modest deficit in retention of the task when assessed 5 days after acquisition training ended. For the Morris water maze, the intertrial interval affected the pattern of learning. While there was no deficit when the training had a short intertrial interval, when there was a long intertrial interval, prenatal oxycodone-exposed rats had poorer acquisition. The spatial learning deficit was characterized by and increased latency to find and a greater distance traveled to the platform in the prenatal oxycodone-exposed rats. These data were corroborated by analysis of the behavioral search strategy, which showed a decreased use of spatial strategies and an increase in non-spatial strategies, especially wall-hugging, in prenatal oxycodone-exposed rats as compared to prenatal water control rats on day 2 of acquisition. These results indicate that prenatal oxycodone exposure consistently impairs learning and memory in

  17. Remote Sensing of Spatial Distributions of Greenhouse Gases in the Los Angles Basin

    NASA Technical Reports Server (NTRS)

    Fu, Dejian; Pongetti, Thomas J.; Sander, Stanley P.; Cheung, Ross; Stutz, Jochen; Park, Chang Hyoun; Li, Qinbin

    2011-01-01

    The Los Angeles air basin is a significant anthropogenic source of greenhouse gases and pollutants including CO2, CH4, N2O, and CO, contributing significantly to regional and global climate change. Recent legislation in California, the California Global Warming Solutions Act (AB32), established a statewide cap for greenhouse gas emissions for 2020 based on 1990 emissions. Verifying the effectiveness of regional greenhouse gas emissions controls requires high-precision, regional-scale measurement methods combined with models that capture the principal anthropogenic and biogenic sources and sinks. We present a novel approach for monitoring the spatial distributions of greenhouse gases in the Los Angeles basin using high resolution remote sensing spectroscopy. We participated in the CalNex 2010 campaign to provide greenhouse gas distributions for comparison between top-down and bottom-up emission estimates.

  18. Remote Sensing of Spatial Distributions of Greenhouse Gases in the Los Angeles Basin

    NASA Technical Reports Server (NTRS)

    Fu, Dejian; Sander, Stanley P.; Pongetti, Thomas J.; Cheung, Ross; Stutz, Jochen

    2010-01-01

    The Los Angeles air basin is a significant anthropogenic source of greenhouse gasses and pollutants including CO2, CH4, N2O, and CO, contributing significantly to regional and global climate change. Recent legislation in California, the California Global Warning Solutions Act (AB32), established a statewide cap for greenhouse gas emissions for 2020 based on 1990 emissions. Verifying the effectiveness of regional greenhouse gas emissions controls requires high-precision, regional-scale measurement methods combined with models that capture the principal anthropogenic and biogenic sources and sinks. We present a novel approach for monitoring the spatial distribution of greenhouse gases in the Los Angeles basin using high resolution remote sensing spectroscopy. We participated in the CalNex 2010 campaign to provide greenhouse gas distributions for comparison between top-down and bottom-up emission estimates.

  19. A robust mosaicking procedure for high spatial resolution remote sensing images

    NASA Astrophysics Data System (ADS)

    Li, Xinghua; Hui, Nian; Shen, Huanfeng; Fu, Yunjie; Zhang, Liangpei

    2015-11-01

    With the rapid development of sensor manufacturing technology, high spatial resolution (HR) images are becoming more easily acquired and more widely used. However, it is common that a region of interest (ROI) cannot be completely acquired from a single image. Image mosaicking can resolve the problem by creating a new large-area image from multiple images with overlapping areas. A typical mosaicking procedure for HR remote sensing images includes three successive steps: tonal adjustment, seamline detection, and image blending. In this paper, we propose a robust mosaicking procedure featuring novel ideas in all three steps, which is aimed at processing HR remote sensing images of urban areas. Firstly, the tonal adjustment is realized by a local moment matching (LMM) algorithm, which solves the nonlinear photometric correlation problem between adjacent images. Secondly, an automatic piecewise dynamic program (APDP) algorithm for seamline detection is proposed to detect the optimal seamline on the overlapped area. Last but not least, we propose a cosine distance weighted blending (CDWB) method to ensure that the seamline is as invisible as possible. Compared to the state-of-the-art methods, the proposed method was proved to be effective in experiments with high resolution aerial and satellite images.

  20. Improving spatial prioritisation for remote marine regions: optimising biodiversity conservation and sustainable development trade-offs.

    PubMed

    Moore, Cordelia H; Radford, Ben T; Possingham, Hugh P; Heyward, Andrew J; Stewart, Romola R; Watts, Matthew E; Prescott, Jim; Newman, Stephen J; Harvey, Euan S; Fisher, Rebecca; Bryce, Clay W; Lowe, Ryan J; Berry, Oliver; Espinosa-Gayosso, Alexis; Sporer, Errol; Saunders, Thor

    2016-01-01

    Creating large conservation zones in remote areas, with less intense stakeholder overlap and limited environmental information, requires periodic review to ensure zonation mitigates primary threats and fill gaps in representation, while achieving conservation targets. Follow-up reviews can utilise improved methods and data, potentially identifying new planning options yielding a desirable balance between stakeholder interests. This research explored a marine zoning system in north-west Australia-a biodiverse area with poorly documented biota. Although remote, it is economically significant (i.e. petroleum extraction and fishing). Stakeholder engagement was used to source the best available biodiversity and socio-economic data and advanced spatial analyses produced 765 high resolution data layers, including 674 species distributions representing 119 families. Gap analysis revealed the current proposed zoning system as inadequate, with 98.2% of species below the Convention on Biological Diversity 10% representation targets. A systematic conservation planning algorithm Maxan provided zoning options to meet representation targets while balancing this with industry interests. Resulting scenarios revealed that conservation targets could be met with minimal impacts on petroleum and fishing industries, with estimated losses of 4.9% and 7.2% respectively. The approach addressed important knowledge gaps and provided a powerful and transparent method to reconcile industry interests with marine conservation. PMID:27556689

  1. Improving spatial prioritisation for remote marine regions: optimising biodiversity conservation and sustainable development trade-offs

    PubMed Central

    Moore, Cordelia H.; Radford, Ben T.; Possingham, Hugh P.; Heyward, Andrew J.; Stewart, Romola R.; Watts, Matthew E.; Prescott, Jim; Newman, Stephen J.; Harvey, Euan S.; Fisher, Rebecca; Bryce, Clay W.; Lowe, Ryan J.; Berry, Oliver; Espinosa-Gayosso, Alexis; Sporer, Errol; Saunders, Thor

    2016-01-01

    Creating large conservation zones in remote areas, with less intense stakeholder overlap and limited environmental information, requires periodic review to ensure zonation mitigates primary threats and fill gaps in representation, while achieving conservation targets. Follow-up reviews can utilise improved methods and data, potentially identifying new planning options yielding a desirable balance between stakeholder interests. This research explored a marine zoning system in north-west Australia–a biodiverse area with poorly documented biota. Although remote, it is economically significant (i.e. petroleum extraction and fishing). Stakeholder engagement was used to source the best available biodiversity and socio-economic data and advanced spatial analyses produced 765 high resolution data layers, including 674 species distributions representing 119 families. Gap analysis revealed the current proposed zoning system as inadequate, with 98.2% of species below the Convention on Biological Diversity 10% representation targets. A systematic conservation planning algorithm Maxan provided zoning options to meet representation targets while balancing this with industry interests. Resulting scenarios revealed that conservation targets could be met with minimal impacts on petroleum and fishing industries, with estimated losses of 4.9% and 7.2% respectively. The approach addressed important knowledge gaps and provided a powerful and transparent method to reconcile industry interests with marine conservation. PMID:27556689

  2. Application of high spatial resolution airborne hyperspectral remote sensing data in thematic information extraction

    NASA Astrophysics Data System (ADS)

    Xu, Hong-gen; Ma, Hong-chao; Li, De-ren; Song, Yan

    2006-10-01

    The airborne hyperspectral remote sensing data, such as PHI, OMIS, has the virtues of high spatial and spectral resolution. Hence, from the view of target classification we can consider that it can provide the ability of discriminating targets more detailedly than other data. So it's important to extract thematic information and update database using this kind of data. Whereas, the hyperspectral data has abundant bands and high between-band correlation, the traditional classification methods such as maximum likelihood classifier (MLC) and spectral angle mapper (SAM) have performed poorly in thematic information extraction. For this reason, we present a new method for thematic information extraction with hyperspectral remote sensing data. We perform classification by means of combining the self-organizing map (SOM) neural network which is considered as full-pixel technique with linear spectral mixture analysis (LSMA) which is considered as mixed-pixel technique. The SOM neural network is improved from some aspects to classify the pure data and find the mixed data. And then the mixed data are unmixed and classified by LSMA. The result of experiment shows that we can have the better performance in thematic information extraction with PHI by this means.

  3. Towards understanding temporal and spatial dynamics of seagrass landscapes using time-series remote sensing

    NASA Astrophysics Data System (ADS)

    Lyons, Mitchell B.; Roelfsema, Chris M.; Phinn, Stuart R.

    2013-03-01

    The spatial and temporal dynamics of seagrasses have been well studied at the leaf to patch scales, however, the link to large spatial extent landscape and population dynamics is still unresolved in seagrass ecology. Traditional remote sensing approaches have lacked the temporal resolution and consistency to appropriately address this issue. This study uses two high temporal resolution time-series of thematic seagrass cover maps to examine the spatial and temporal dynamics of seagrass at both an inter- and intra-annual time scales, one of the first globally to do so at this scale. Previous work by the authors developed an object-based approach to map seagrass cover level distribution from a long term archive of Landsat TM and ETM+ images on the Eastern Banks (≈200 km2), Moreton Bay, Australia. In this work a range of trend and time-series analysis methods are demonstrated for a time-series of 23 annual maps from 1988 to 2010 and a time-series of 16 monthly maps during 2008-2010. Significant new insight was presented regarding the inter- and intra-annual dynamics of seagrass persistence over time, seagrass cover level variability, seagrass cover level trajectory, and change in area of seagrass and cover levels over time. Overall we found that there was no significant decline in total seagrass area on the Eastern Banks, but there was a significant decline in seagrass cover level condition. A case study of two smaller communities within the Eastern Banks that experienced a decline in both overall seagrass area and condition are examined in detail, highlighting possible differences in environmental and process drivers. We demonstrate how trend and time-series analysis enabled seagrass distribution to be appropriately assessed in context of its spatial and temporal history and provides the ability to not only quantify change, but also describe the type of change. We also demonstrate the potential use of time-series analysis products to investigate seagrass growth and

  4. Spatial Predictive Modeling and Remote Sensing of Land Use Change in the Chesapeake Bay Watershed

    NASA Technical Reports Server (NTRS)

    Goetz, Scott J.; Bockstael, Nancy E.; Jantz, Claire A.

    2005-01-01

    This project was focused on modeling the processes by which increasing demand for developed land uses, brought about by changes in the regional economy and the socio-demographics of the region, are translated into a changing spatial pattern of land use. Our study focused on a portion of the Chesapeake Bay Watershed where the spatial patterns of sprawl represent a set of conditions generally prevalent in much of the U.S. Working in the region permitted us access to (i) a time-series of multi-scale and multi-temporal (including historical) satellite imagery and (ii) an established network of collaborating partners and agencies willing to share resources and to utilize developed techniques and model results. In addition, a unique parcel-level tax assessment database and linked parcel boundary maps exists for two counties in the Maryland portion of this region that made it possible to establish a historical cross-section time-series database of parcel level development decisions. Scenario analyses of future land use dynamics provided critical quantitative insight into the impact of alternative land management and policy decisions. These also have been specifically aimed at addressing growth control policies aimed at curbing exurban (sprawl) development. Our initial technical approach included three components: (i) spatial econometric modeling of the development decision, (ii) remote sensing of suburban change and residential land use density, including comparisons of past change from Landsat analyses and more traditional sources, and (iii) linkages between the two through variable initialization and supplementation of parcel level data. To these we added a fourth component, (iv) cellular automata modeling of urbanization, which proved to be a valuable addition to the project. This project has generated both remote sensing and spatially explicit socio-economic data to estimate and calibrate the parameters for two different types of land use change models and has

  5. Mapping of groundwater potential zones across Ghana using remote sensing, geographic information systems, and spatial modeling.

    PubMed

    Gumma, Murali Krishna; Pavelic, Paul

    2013-04-01

    Groundwater development across much of sub-Saharan Africa is constrained by a lack of knowledge on the suitability of aquifers for borehole construction. The main objective of this study was to map groundwater potential at the country-scale for Ghana to identify locations for developing new supplies that could be used for a range of purposes. Groundwater potential zones were delineated using remote sensing and geographical information system (GIS) techniques drawing from a database that includes climate, geology, and satellite data. Subjective scores and weights were assigned to each of seven key spatial data layers and integrated to identify groundwater potential according to five categories ranging from very good to very poor derived from the total percentage score. From this analysis, areas of very good groundwater potential are estimated to cover 689,680 ha (2.9 % of the country), good potential 5,158,955 ha (21.6 %), moderate potential 10,898,140 ha (45.6 %), and poor/very poor potential 7,167,713 ha (30 %). The results were independently tested against borehole yield data (2,650 measurements) which conformed to the anticipated trend between groundwater potential and borehole yield. The satisfactory delineation of groundwater potential zones through spatial modeling suggests that groundwater development should first focus on areas of the highest potential. This study demonstrates the importance of remote sensing and GIS techniques in mapping groundwater potential at the country-scale and suggests that similar methods could be applied across other African countries and regions. PMID:22892995

  6. Photogrammetry and remote sensing for visualization of spatial data in a virtual reality environment

    NASA Astrophysics Data System (ADS)

    Bhagawati, Dwipen

    2001-07-01

    Researchers in many disciplines have started using the tool of Virtual Reality (VR) to gain new insights into problems in their respective disciplines. Recent advances in computer graphics, software and hardware technologies have created many opportunities for VR systems, advanced scientific and engineering applications being among them. In Geometronics, generally photogrammetry and remote sensing are used for management of spatial data inventory. VR technology can be suitably used for management of spatial data inventory. This research demonstrates usefulness of VR technology for inventory management by taking the roadside features as a case study. Management of roadside feature inventory involves positioning and visualization of the features. This research has developed a methodology to demonstrate how photogrammetric principles can be used to position the features using the video-logging images and GPS camera positioning and how image analysis can help produce appropriate texture for building the VR, which then can be visualized in a Cave Augmented Virtual Environment (CAVE). VR modeling was implemented in two stages to demonstrate the different approaches for modeling the VR scene. A simulated highway scene was implemented with the brute force approach, while modeling software was used to model the real world scene using feature positions produced in this research. The first approach demonstrates an implementation of the scene by writing C++ codes to include a multi-level wand menu for interaction with the scene that enables the user to interact with the scene. The interactions include editing the features inside the CAVE display, navigating inside the scene, and performing limited geographic analysis. The second approach demonstrates creation of a VR scene for a real roadway environment using feature positions determined in this research. The scene looks realistic with textures from the real site mapped on to the geometry of the scene. Remote sensing and

  7. Remote sensing and spatial analysis based study for detecting deforestation and the associated drivers

    NASA Astrophysics Data System (ADS)

    El-Abbas, Mustafa M.; Csaplovics, Elmar; Deafalla, Taisser H.

    2013-10-01

    Nowadays, remote-sensing technologies are becoming increasingly interlinked to the issue of deforestation. They offer a systematized and objective strategy to document, understand and simulate the deforestation process and its associated causes. In this context, the main goal of this study, conducted in the Blue Nile region of Sudan, in which most of the natural habitats were dramatically destroyed, was to develop spatial methodologies to assess the deforestation dynamics and its associated factors. To achieve that, optical multispectral satellite scenes (i.e., ASTER and LANDSAT) integrated with field survey in addition to multiple data sources were used for the analyses. Spatiotemporal Object Based Image Analysis (STOBIA) was applied to assess the change dynamics within the period of study. Broadly, the above mentioned analyses include; Object Based (OB) classifications, post-classification change detection, data fusion, information extraction and spatial analysis. Hierarchical multi-scale segmentation thresholds were applied and each class was delimited with semantic meanings by a set of rules associated with membership functions. Consequently, the fused multi-temporal data were introduced to create detailed objects of change classes from the input LU/LC classes. The dynamic changes were quantified and spatially located as well as the spatial and contextual relations from adjacent areas were analyzed. The main finding of the present study is that, the forest areas were drastically decreased, while the agrarian structure in conversion of forest into agricultural fields and grassland was the main force of deforestation. In contrast, the capability of the area to recover was clearly observed. The study concludes with a brief assessment of an 'oriented' framework, focused on the alarming areas where serious dynamics are located and where urgent plans and interventions are most critical, guided with potential solutions based on the identified driving forces.

  8. Spatial-Spectral Classification Based on the Unsupervised Convolutional Sparse Auto-Encoder for Hyperspectral Remote Sensing Imagery

    NASA Astrophysics Data System (ADS)

    Han, Xiaobing; Zhong, Yanfei; Zhang, Liangpei

    2016-06-01

    Current hyperspectral remote sensing imagery spatial-spectral classification methods mainly consider concatenating the spectral information vectors and spatial information vectors together. However, the combined spatial-spectral information vectors may cause information loss and concatenation deficiency for the classification task. To efficiently represent the spatial-spectral feature information around the central pixel within a neighbourhood window, the unsupervised convolutional sparse auto-encoder (UCSAE) with window-in-window selection strategy is proposed in this paper. Window-in-window selection strategy selects the sub-window spatial-spectral information for the spatial-spectral feature learning and extraction with the sparse auto-encoder (SAE). Convolution mechanism is applied after the SAE feature extraction stage with the SAE features upon the larger outer window. The UCSAE algorithm was validated by two common hyperspectral imagery (HSI) datasets - Pavia University dataset and the Kennedy Space Centre (KSC) dataset, which shows an improvement over the traditional hyperspectral spatial-spectral classification methods.

  9. High spatial resolution remote sensing imagery improves GPP predictions in disturbed, semi-arid woodlands

    NASA Astrophysics Data System (ADS)

    Krofcheck, D. J.; Eitel, J.; Vierling, L. A.; Schulthess, U.; Litvak, M. E.

    2012-12-01

    Climate across the globe is changing and consequently the productivity of terrestrial vegetation is changing with it. Gross primary productivity (GPP) is an integral part of the carbon cycle, yet challenging to measure everywhere, all the time. Efforts to estimate GPP in the context of climate change are becoming continually more salient of the need for models sensitive to the heterogeneous nature of drought and pest induced disturbance. Given the increased availability of high spatial resolution remotely sensed imagery, their use in ecosystem scale GPP estimation is becoming increasingly viable. We used a simple linear model with inputs derived from RapidEye time series data (5 meter spatial resolution) as compared to MODIS inputs (250 meter spatial resolution) to estimate GPP in intact and girdled PJ woodland to simulate drought and pest induced disturbance. An area equal to the MODIS pixels measured was aggregated using RapidEye data centered on the flux towers for comparison purposes. We generated four model runs, two using only MODIS or RapidEye spectral vegetation indices (VIs) and two using MODIS and RapidEye VIs combined at both the control and disturbed tower site. Our results suggest that for undisturbed regions, MODIS derived VIs perform better than the higher spatial resolution RapidEye VIs when a moisture sensitive index is incorporated into the model (RMSE of 17.51for MODIS vs. 22.71 for RapidEye). Modeling GPP in disturbed regions however benefits from the inclusion of high spatial resolution data (RMSE of 14.83 for MODIS vs. 14.70 for RapidEye). This discrepancy may have to do with the disparate scale of a MODIS pixel and the size of the tower fetch. Our results suggest that the best source of VI's for the modeling GPP in semi-arid woodlands depends on the level of disturbance in the landscape. Given that the rate and extent of drought and insect induced mortality events in terrestrial forests are projected to increase with our changing climate

  10. Remote sensing, geographical information systems, and spatial modeling for analyzing public transit services

    NASA Astrophysics Data System (ADS)

    Wu, Changshan

    Public transit service is a promising transportation mode because of its potential to address urban sustainability. Current ridership of public transit, however, is very low in most urban regions, particularly those in the United States. This woeful transit ridership can be attributed to many factors, among which poor service quality is key. Given this, there is a need for transit planning and analysis to improve service quality. Traditionally, spatially aggregate data are utilized in transit analysis and planning. Examples include data associated with the census, zip codes, states, etc. Few studies, however, address the influences of spatially aggregate data on transit planning results. In this research, previous studies in transit planning that use spatially aggregate data are reviewed. Next, problems associated with the utilization of aggregate data, the so-called modifiable areal unit problem (MAUP), are detailed and the need for fine resolution data to support public transit planning is argued. Fine resolution data is generated using intelligent interpolation techniques with the help of remote sensing imagery. In particular, impervious surface fraction, an important socio-economic indicator, is estimated through a fully constrained linear spectral mixture model using Landsat Enhanced Thematic Mapper Plus (ETM+) data within the metropolitan area of Columbus, Ohio in the United States. Four endmembers, low albedo, high albedo, vegetation, and soil are selected to model heterogeneous urban land cover. Impervious surface fraction is estimated by analyzing low and high albedo endmembers. With the derived impervious surface fraction, three spatial interpolation methods, spatial regression, dasymetric mapping, and cokriging, are developed to interpolate detailed population density. Results suggest that cokriging applied to impervious surface is a better alternative for estimating fine resolution population density. With the derived fine resolution data, a multiple

  11. Daily access to sucrose impairs aspects of spatial memory tasks reliant on pattern separation and neural proliferation in rats.

    PubMed

    Reichelt, Amy C; Morris, Margaret J; Westbrook, Reginald Frederick

    2016-07-01

    High sugar diets reduce hippocampal neurogenesis, which is required for minimizing interference between memories, a process that involves "pattern separation." We provided rats with 2 h daily access to a sucrose solution for 28 d and assessed their performance on a spatial memory task. Sucrose consuming rats discriminated between objects in novel and familiar locations when there was a large spatial separation between the objects, but not when the separation was smaller. Neuroproliferation markers in the dentate gyrus of the sucrose-consuming rats were reduced relative to controls. Thus, sucrose consumption impaired aspects of spatial memory and reduced hippocampal neuroproliferation. PMID:27317199

  12. Remote sensing, geographical information system and spatial analysis for schistosomiasis epidemiology and ecology in Africa.

    PubMed

    Simoonga, C; Utzinger, J; Brooker, S; Vounatsou, P; Appleton, C C; Stensgaard, A S; Olsen, A; Kristensen, T K

    2009-11-01

    Beginning in 1970, the potential of remote sensing (RS) techniques, coupled with geographical information systems (GIS), to improve our understanding of the epidemiology and control of schistosomiasis in Africa, has steadily grown. In our current review, working definitions of RS, GIS and spatial analysis are given, and applications made to date with RS and GIS for the epidemiology and ecology of schistosomiasis in Africa are summarised. Progress has been made in mapping the prevalence of infection in humans and the distribution of intermediate host snails. More recently, Bayesian geostatistical modelling approaches have been utilized for predicting the prevalence and intensity of infection at different scales. However, a number of challenges remain; hence new research is needed to overcome these limitations. First, greater spatial and temporal resolution seems important to improve risk mapping and understanding of transmission dynamics at the local scale. Second, more realistic risk profiling can be achieved by taking into account information on people's socio-economic status; furthermore, future efforts should incorporate data on domestic access to clean water and adequate sanitation, as well as behavioural and educational issues. Third, high-quality data on intermediate host snail distribution should facilitate validation of infection risk maps and modelling transmission dynamics. Finally, more emphasis should be placed on risk mapping and prediction of multiple species parasitic infections in an effort to integrate disease risk mapping and to enhance the cost-effectiveness of their control. PMID:19627627

  13. Elevated dynorphin in the hippocampal formation of aged rats: Relation to cognitive impairment on a spatial learning task

    SciTech Connect

    Jiang, Hannkuang; Owyang, V.; Hong, Jaushyong; Gallagher, M. )

    1989-04-01

    Radioimmunoassay revealed increased dynorphin A(1-8)-like immunoreactivity (dynA(1-8)LI) in the aged rat brain. Among a number of brain regions examined, an age-related dynA(1-8)LI elevation was found only in the hippocampal formation and frontal cortex. Moreover, the increase in dynA(1-8)LI in the aged hippocampus was associated with a decline in spatial learning ability: dynA(1-8)LI distinguished aged rats that were behaviorally impaired from aged cohorts that learned the spatial task as rapidly as younger animals. Northern blot hybridization using a {sup 32}P-labeled complementary RNA probe encoding rat prodynorphin indicated that the abundance of prodynorphin mRNA was also significantly increased in the hippocampal formation of aged rats with identified spatial learning impairments.

  14. Remote sensing and spatial analysis of aeolian sand dunes: A review and outlook

    NASA Astrophysics Data System (ADS)

    Hugenholtz, Chris H.; Levin, Noam; Barchyn, Thomas E.; Baddock, Matthew C.

    2012-03-01

    For more than four decades remote sensing images have been used to document and understand the evolution of aeolian sand dunes. Early studies focused on mapping and classifying dunes. Recent advances in sensor technology and software have allowed investigators to move towards quantitative investigation of dune form evolution and pattern development. These advances have taken place alongside progress in numerical models, which are capable of simulating the multitude of dune patterns observed in nature. The potential to integrate remote sensing (RS), spatial analysis (SA), and modeling to predict the future changes of real-world dune systems is steadily becoming a reality. Here we present a comprehensive review of significant recent advances involving RS and SA. Our objective is to demonstrate the capacity of these technologies to provide new insight on three important research domains: (1) dune activity, (2) dune patterns and hierarchies, and (3) extra-terrestrial dunes. We outline how several recent advances have capitalized on the improved spatial and spectral resolution of RS data, the availability of topographic data, and new SA methods and software. We also discuss some of the key research challenges and opportunities in the application of RS and SA dune field, including: the integration of RS data with field-based measurements of vegetation cover, structure, and aeolian transport rate in order to develop predictive models of dune field activity; expanding the observational evidence of dune form evolution at temporal and spatial scales that can be used to validate and refine simulation models; the development and application of objective and reproducible SA methods for characterizing dune field pattern; and, expanding efforts to quantify three-dimensional topographic changes of dune fields in order to develop improved understanding of spatio-temporal patterns of erosion and deposition. Overall, our review indicates a progressive evolution in the way sand dunes

  15. Spatially Explicit Large Area Biomass Estimation: Three Approaches Using Forest Inventory and Remotely Sensed Imagery in a GIS

    PubMed Central

    Wulder, Michael A.; White, Joanne C.; Fournier, Richard A.; Luther, Joan E.; Magnussen, Steen

    2008-01-01

    Forest inventory data often provide the required base data to enable the large area mapping of biomass over a range of scales. However, spatially explicit estimates of above-ground biomass (AGB) over large areas may be limited by the spatial extent of the forest inventory relative to the area of interest (i.e., inventories not spatially exhaustive), or by the omission of inventory attributes required for biomass estimation. These spatial and attributional gaps in the forest inventory may result in an underestimation of large area AGB. The continuous nature and synoptic coverage of remotely sensed data have led to their increased application for AGB estimation over large areas, although the use of these data remains challenging in complex forest environments. In this paper, we present an approach to generating spatially explicit estimates of large area AGB by integrating AGB estimates from multiple data sources; 1. using a lookup table of conversion factors applied to a non-spatially exhaustive forest inventory dataset (R2 = 0.64; RMSE = 16.95 t/ha), 2. applying a lookup table to unique combinations of land cover and vegetation density outputs derived from remotely sensed data (R2 = 0.52; RMSE = 19.97 t/ha), and 3. hybrid mapping by augmenting forest inventory AGB estimates with remotely sensed AGB estimates where there are spatial or attributional gaps in the forest inventory data. Over our 714,852 ha study area in central Saskatchewan, Canada, the AGB estimate generated from the forest inventory was approximately 40 Mega tonnes (Mt); however, the inventory estimate represents only 51% of the total study area. The AGB estimate generated from the remotely sensed outputs that overlap those made from the forest inventory based approach differ by only 2 %; however in total, the remotely sensed estimate is 30 % greater (58 Mt) than the estimate generated from the forest inventory when the entire study area is accounted for. Finally, using the hybrid approach, whereby

  16. Effect of Pentoxifylline on Ischemia- induced Brain Damage and Spatial Memory Impairment in Rat

    PubMed Central

    Movassaghi, Shabnam; Nadia Sharifi, Zahra; Soleimani, Mansooreh; Joghataii, Mohammad Taghi; Hashemi, Mehrdad; Shafaroodi, Hamed; Mehdizadeh, Mehdi

    2012-01-01

    Objective(s) The brief interruption of cerebral blood flow causes permanent brain damage and behavioral dysfunction. The hippocampus is highly vulnerable to ischemic insults, particularly the CA1 pyramidal cell layer. There is no effective pharmacological strategy for improving brain tissue damage induced by cerebral ischemia. Previous studies reported that pentoxifylline (PTX) has a neuroprotective effect on brain trauma. The possible neuroprotector effects of PTX on behavioral deficit were studied in male Wistar rats subjected to a model of transient global brain ischemia. Materials and Methods Animals (n= 32) were assigned to control, sham-operated, vehicle, and PTX- treated (200 mg/kg IP) groups. PTX administered at 1hr before and 3 hr after ischemia. Global cerebral ischemia was induced by bilateral common carotid artery occlusion, followed by reperfusion. Results Morris Water maze testing revealed that PTX administration in cerebral ischemia significantly improved hippocampal-dependent memory and cognitive spatial abilities after reperfusion as compared to sham-operated and vehicle-treated animals. After the behavioral test, the rats were sacrificed and brain sections were stained with Nissl staining. There were no significant differences between number of pyramidal cells in both control and PTX groups. Conclusion Our study demonstrated that pentoxifylline had a protective effect on rats with transient global ischemia and could reduce cognitive impairment. PMID:23493977

  17. Ascorbic Acid Ameliorates Nicotine Exposure Induced Impaired Spatial Memory Performance in Rats

    PubMed Central

    Sirasanagandla, SR; Rooben, RK; Rajkumar; Narayanan, SN; Jetti, R

    2014-01-01

    Introduction: The long lasting behavioural and cognitive impairments in offspring prenatally exposed to nicotine have been confirmed in animal models. In the present study, we investigated the effect of ascorbic acid on prenatal nicotine exposure induced behavioural deficits in male offspring of rats. Methods: The pregnant Wistar dams were divided into four groups of six rats: control, vehicle control, nicotine and nicotine+ascorbic acid groups. The nicotine group received daily dose of subcutaneous injections of 0.96 mg/kg body weight (bw) nicotine free base throughout gestation. Pregnant dams in nicotine+ascorbic acid group were first given nicotine free base (0.96 mg/kg bw/day; subcutaneous route) followed by ascorbic acid (50 mg/kg bw/day, orally) daily throughout gestation. The cognitive function of male offspring of all the experimental groups was studied using Morris water maze test at postnatal day 40. Results: Prenatal nicotine exposure altered spatial learning and memory in male offspring. However, treatment with ascorbic acid ameliorated these changes in rats. Conclusion: Ascorbic acid supplementation was found to be effective in preventing the prenatal nicotine exposure induced cognitive deficits in rat offspring to some extent. PMID:25429474

  18. Enhanced Odor Discrimination and Impaired Olfactory Memory by Spatially Controlled Switch of AMPA Receptors

    PubMed Central

    2005-01-01

    Genetic perturbations of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptors (AMPARs) are widely used to dissect molecular mechanisms of sensory coding, learning, and memory. In this study, we investigated the role of Ca2+-permeable AMPARs in olfactory behavior. AMPAR modification was obtained by depletion of the GluR-B subunit or expression of unedited GluR-B(Q), both leading to increased Ca2+ permeability of AMPARs. Mice with this functional AMPAR switch, specifically in forebrain, showed enhanced olfactory discrimination and more rapid learning in a go/no-go operant conditioning task. Olfactory memory, however, was dramatically impaired. GluR-B depletion in forebrain was ectopically variable (“mosaic”) among individuals and strongly correlated with decreased olfactory memory in hippocampus and cortex. Accordingly, memory was rescued by transgenic GluR-B expression restricted to piriform cortex and hippocampus, while enhanced odor discrimination was independent of both GluR-B variability and transgenic GluR-B expression. Thus, correlated differences in behavior and levels of GluR-B expression allowed a mechanistic and spatial dissection of olfactory learning, discrimination, and memory capabilities. PMID:16216087

  19. Paternal alcohol consumption in the rat impairs spatial learning performance in male offspring.

    PubMed

    Wozniak, D F; Cicero, T J; Kettinger, L; Meyer, E R

    1991-01-01

    Pubescent (30 day old) male rats were maintained on an alcohol liquid diet containing 35% ethanol-derived calories (ALC) for 39 days or were pairfed an isocaloric control diet (PF). The concentration of alcohol in the diet was gradually increased to permit adaptation, then stabilized and then gradually tapered to prevent an alcohol withdrawal syndrome. Following a drug-free period (2 weeks), the males were mated with nontreated females. Offspring were evaluated on several developmental indices and on various learning/memory tasks to assess functional deficits in adulthood. Offspring sired by ALC-treated males did not differ from the offspring of PF males on several developmental parameters including body weights, when developmental landmarks appeared, or on tests of sensorimotor development. As adults, male offspring groups did not differ on tests of activity or on an object exploration/recognition task. However, male offspring of ALC-treated males demonstrated impaired acquisition performance (days and errors to criterion) on a win-shift spatial discrimination in an eight-arm radial maze and on a win-stay discrimination (days to criterion) conducted in a T-maze at a later age. The radial maze results were replicated in a subsequent experiment using different groups of rats. PMID:1796134

  20. Noise induced hearing loss impairs spatial learning/memory and hippocampal neurogenesis in mice

    PubMed Central

    Liu, Lijie; Shen, Pei; He, Tingting; Chang, Ying; Shi, Lijuan; Tao, Shan; Li, Xiaowei; Xun, Qingying; Guo, Xiaojing; Yu, Zhiping; Wang, Jian

    2016-01-01

    Hearing loss has been associated with cognitive decline in the elderly and is considered to be an independent risk factor for dementia. One of the most common causes for acquired sensorineural hearing loss is exposure to excessive noise, which has been found to impair learning ability and cognitive performance in human subjects and animal models. Noise exposure has also been found to depress neurogenesis in the hippocampus. However, the effect is mainly attributed to the oxidant stress of noise on the cognitive brain. In the present study, young adult CBA/CAJ mice (between 1.5 and 2 months of age) were briefly exposed a high sound level to produce moderate-to-severe hearing loss. In both the blood and hippocampus, only transient oxidative stress was observed after noise exposure. However, a deficit in spatial learning/memory was revealed 3 months after noise exposure. Moreover, the deficit was correlated with the degree of hearing loss and was associated with a decrease in neurogenesis in the hippocampus. We believe that the observed effects were likely due to hearing loss rather than the initial oxidant stress, which only lasted for a short period of time. PMID:26842803

  1. CLASSIFICATION OF HIGH SPATIAL RESOLUTION, HYPERSPECTRAL REMOTE SENSING IMAGERY OF THE LITTLE MIAMI RIVER WATERSHED IN SOUTHWEST OHIO, USA (FINAL)

    EPA Science Inventory

    The document and associated land use/land cover (LULC) coverage, entitled Classification of High Spatial Resolution, Hyperspectral Remote Sensing Imagery of the Little Miami River Watershed in Southwest Ohio, USA, is the result of a collaborative effort among an interdisci...

  2. Spatially distributed evapotranspiration estimation using remote sensing and ground-based radiometers over cotton at Maricopa, Arizona

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spatially distributed estimates of evapotranspiration (ET) over agricultural lands could be valuable for water management in arid environments and for monitoring irrigated croplands. In recent year various ET estimation approaches have been developed that utilize remote sense data to provide the nee...

  3. Spatial patterns of brain amyloid-beta burden and atrophy rate associations in mild cognitive impairment.

    PubMed

    Tosun, Duygu; Schuff, Norbert; Mathis, Chester A; Jagust, William; Weiner, Michael W

    2011-04-01

    Amyloid-β accumulation in the brain is thought to be one of the earliest events in Alzheimer's disease, possibly leading to synaptic dysfunction, neurodegeneration and cognitive/functional decline. The earliest detectable changes seen with neuroimaging appear to be amyloid-β accumulation detected by (11)C-labelled Pittsburgh compound B positron emission tomography imaging. However, some individuals tolerate high brain amyloid-β loads without developing symptoms, while others progressively decline, suggesting that events in the brain downstream from amyloid-β deposition, such as regional brain atrophy rates, play an important role. The main purpose of this study was to understand the relationship between the regional distributions of increased amyloid-β and the regional distribution of increased brain atrophy rates in patients with mild cognitive impairment. To simultaneously capture the spatial distributions of amyloid-β and brain atrophy rates, we employed the statistical concept of parallel independent component analysis, an effective method for joint analysis of multimodal imaging data. Parallel independent component analysis identified significant relationships between two patterns of amyloid-β deposition and atrophy rates: (i) increased amyloid-β burden in the left precuneus/cuneus and medial-temporal regions was associated with increased brain atrophy rates in the left medial-temporal and parietal regions; and (ii) in contrast, increased amyloid-β burden in bilateral precuneus/cuneus and parietal regions was associated with increased brain atrophy rates in the right medial temporal regions. The spatial distribution of increased amyloid-β and the associated spatial distribution of increased brain atrophy rates embrace a characteristic pattern of brain structures known for a high vulnerability to Alzheimer's disease pathology, encouraging for the use of (11)C-labelled Pittsburgh compound B positron emission tomography measures as early indicators of

  4. Design of a prototype device for remote patient care with mild cognitive impairment

    NASA Astrophysics Data System (ADS)

    Sanchez-Ocampo, M.; Segura-Giraldo, B.; Floréz-Hurtado, R.; Cortés-Aguirre, C.

    2016-04-01

    This paper describes the design of a prototype telecare system, which allows to provide home care to patients with mild cognitive impairment and thus ensures their permanence in their usual environment. Telecare is oriented towards people who require constant attention due to conditions of advanced age, illness, physical risk or limited capabilities. Telecare offers these people a greater degree of independence. QFD methodology is used to develop electronic devices intended to monitor the environment and physiological state of the user continuously, providing communication between the telecare system and a monitoring center in order to take the most appropriate actions in any abnormal event.

  5. Adult-onset focal expression of mutated human tau in the hippocampus impairs spatial working memory of rats

    PubMed Central

    Mustroph, M.L.; King, M.A.; Klein, R.L.; Ramirez, J.J.

    2012-01-01

    Tauopathy in the hippocampus is one of the earliest cardinal features of Alzheimer’s disease (AD), a condition characterized by progressive memory impairments. In fact, density of tau neurofibrillary tangles (NFTs) in the hippocampus strongly correlates with severity of cognitive impairments in AD. In the present study, we employed a somatic cell gene transfer technique to create a rodent model of tauopathy by injecting a recombinant adeno-associated viral vector with a mutated human tau gene (P301L) into the hippocampus of adult rats. The P301L mutation is causal for frontotemporal dementia with parkinsonism-17 (FTDP-17), but it has been used for studying memory effects characteristic of AD in transgenic mice. To ascertain if P301L-induced mnemonic deficits are persistent, animals were tested for 6 months. It was hypothesized that adult-onset, spatially restricted tau expression in the hippocampus would produce progressive spatial working memory deficits on a learned alternation task. Rats injected with the tau vector exhibited persistent impairments on the hippocampal-dependent task beginning at about 6 weeks post-transduction compared to rats injected with a green fluorescent protein vector. Histological analysis of brains for expression of human tau revealed hyperphosphorylated human tau and NFTs in the hippocampus in experimental animals only. Thus, adult-onset, vector-induced tauopathy spatially restricted to the hippocampus progressively impaired spatial working memory in rats. We conclude that the model faithfully reproduces histological and behavioral findings characteristic of dementing tauopathies. The rapid onset of sustained memory impairment establishes a preclinical model particularly suited to the development of potential tauopathy therapeutics. PMID:22561128

  6. The Need for High Spatial Resolution Multispectral Thermal Remote Sensing Data In Urban Heat Island Research

    NASA Technical Reports Server (NTRS)

    Quattrochi, Dale A.; Luvall, Jeffrey C.

    2006-01-01

    Although the study of the Urban Heat Island (UHI) effect dates back to the early 1800's when Luke Howard discovered London s heat island, it has only been with the advent of thermal remote sensing systems that the extent, characteristics, and impacts of the UHI have become to be understood. Analysis of the UHI effect is important because above all, this phenomenon can directly influence the health and welfare of urban residents. For example, in 1995, over 700 people died in Chicago due to heat-related causes. UHI s are characterized by increased temperature in comparison to rural areas and mortality rates during a heat wave increase exponentially with the maximum temperature, an effect that is exacerbated by the UHI. Aside from the direct impacts of the UHI on temperature, UHI s can produce secondary effects on local meteorology, including altering local wind patterns, increased development of clouds and fog, and increasing rates of precipitation either over, or downwind, of cities. Because of the extreme heterogeneity of the urban surface, in combination with the sprawl associated with urban growth, thermal infrared (TIR) remote sensing data have become of significant importance in understanding how land cover and land use characteristics affect the development and intensification of the UHI. TIR satellite data have been used extensively to analyze the surface temperature regimes of cities to help observe and measure the impacts of surface temperatures across the urban landscape. However, the spatial scales at which satellite TIR data are collected are for the most part, coarse, with the finest readily available TIR data collected by the Landsat ETM+ sensor at 60m spatial resolution. For many years, we have collected high spatial resolution (10m) data using an airborne multispectral TIR sensor over a number of cities across the United States. These high resolution data have been used to develop an understanding of how discrete surfaces across the urban environment

  7. The Need for High Spatial Resolution Multispectral Thermal Remote Sensing Data In Urban Heat Island Research

    NASA Astrophysics Data System (ADS)

    Quattrochi, D. A.; Luvall, J. C.

    2006-12-01

    Although the study of the Urban Heat Island (UHI) effect dates back to the early 1800's when Luke Howard discovered London's heat island, it has only been with the advent of thermal remote sensing systems that the extent, characteristics, and impacts of the UHI have become to be understood. Analysis of the UHI effect is important because above all, this phenomenon can directly influence the health and welfare of urban residents. For example, in 1995, over 700 people died in Chicago due to heat-related causes. UHI's are characterized by increased temperature in comparison to rural areas and mortality rates during a heat wave increase exponentially with the maximum temperature, an effect that is exacerbated by the UHI. Aside from the direct impacts of the UHI on temperature, UHI's can produce secondary effects on local meteorology, including altering local wind patterns, increased development of clouds and fog, and increasing rates of precipitation either over, or downwind, of cities. Because of the extreme heterogeneity of the urban surface, in combination with the sprawl associated with urban growth, thermal infrared (TIR) remote sensing data have become of significant importance in understanding how land cover and land use characteristics affect the development and intensification of the UHI. TIR satellite data have been used extensively to analyze the surface temperature regimes of cities to help observe and measure the impacts of surface temperatures across the urban landscape. However, the spatial scales at which satellite TIR data are collected are for the most part, coarse, with the finest readily available TIR data collected by the Landsat ETM+ sensor at 60m spatial resolution. For many years, we have collected high spatial resolution (10m) data using an airborne multispectral TIR sensor over a number of cities across the United States. These high resolution data have been used to develop an understanding of how discrete surfaces across the urban environment

  8. Late Enrichment Maintains Accurate Recent and Remote Spatial Memory Only in Aged Rats That Were Unimpaired When Middle Aged

    ERIC Educational Resources Information Center

    Fuchs, Fanny; Herbeaux, Karine; Aufrere, Noémie; Kelche, Christian; Mathis, Chantal; Barbelivien, Alexandra; Majchrzak, Monique

    2016-01-01

    Exposure of rodents to a stimulating environment has beneficial effects on some cognitive functions that are impaired during physiological aging, and especially spatial reference memory. The present study investigated whether environmental enrichment rescues these functions in already declining subjects and/or protects them from subsequent…

  9. MEMANTINE ATTENUATES THE OKADAIC ACID INDUCED SHORT-TERM SPATIAL MEMORY IMPAIRMENT AND HIPPOCAMPAL CELL LOSS IN RATS.

    PubMed

    Dashniani, M; Chighladze, M; Burjanadze, M; Beselia, G; Kruashvili, L

    2016-03-01

    In the present study, the possible beneficial effect of memantine on the Okadaic Acid (OA) induced spatial short-term memory impairment was examined in spatial alternation task, and the neuroprotective potential of memantine on OA-induced structural changes in the hippocampus was evaluated by Nissl staining. OA was dissolved in artificial cerebrospinal fluid (aCSF) and injected intracerebroventriculary (ICV) 200 ng in a volume of 10 μl bilaterally. Vehicle control received aCSF ICV bilaterally. Control and OA injected rats were divided into 2 subgroups injected i.p. with saline or memantine (5 mg/kg). Memantine or saline were given daily for 13 days starting from the day of OA injection. Behavioral study showed that bilateral ICV microinjection of OA induced impairment in spatial short-term memory. Nissl staining in the present study showed that the ICV microinjection of OA significantly decreased the number of surviving pyramidal neurons in the CA1 region of the hippocampus. Chronic administration of memantine effectively attenuated OA induced spatial short-term memory impairment and the OA-induced neuropathological changes in the hippocampus. Therefore, ICV injection of OA can be used as an experimental model to study mechanisms of neurodegeneration and define novel therapeutics targets for AD pathology. PMID:27119837

  10. Spatially distributed storm runoff modeling using remote sensing and geographic information systems

    NASA Astrophysics Data System (ADS)

    Melesse, Assefa Mekonnen

    Advances in scientific knowledge and new techniques of remote sensing permit a better understanding of the physical land features governing hydrologic processes, and make possible efficient, large-scale hydrologic modeling. The need for land-cover and hydrologic response change detection at a larger scale and at times of the year when hydrologic studies are critical makes satellite imagery the most cost effective, efficient and reliable source of data. The use of a Geographic Information System (GIS) to store, manipulate and visualize these data, and ultimately to estimate runoff from watersheds, has gained increasing attention in recent years. In this work, remotely-sensed data and GIS tools were used to estimate the changes in land-cover, and to estimate runoff response, for three watersheds (Etonia, Econlockhatchee, and S-65A sub-basins) in Florida. Land-use information from Digital Orthophoto Quarter Quadrangles (DOQQ), Landsat Thematic Mapper (TM), and Enhanced Thematic Mapper Plus (ETM+) were analyzed for the years 1973, 1984, 1990, 1995, and 2000. Spatial distribution of land-cover was assessed over time. The corresponding infiltration excess runoff response of the study areas due to these changes was estimated using the United States Department of Agriculture, Natural Resources Conservation Service Curve Number (USDA-NRCS-CN) method. A Digital Elevation Model (DEM)-GIS technique was developed to predict stream response to runoff events based on the travel time from each grid cell to the watershed outlet. The method was tested on a representative watershed (Simms Creek) in the Etonia sub-basin. Simulated and observed runoff volume and hydrographs were compared for 17 storm events. Isolated storms, with volumes of not less than 12.75 mm (0.5 inch) were selected. This is the minimum amount of rainfall volume recommended for the NRCS-CN method. Results show that the model predicts the runoff response of the study area with an average efficiency of 57

  11. Spatial distribution of the timing of rainfall extremes derived by remote sensing and raingauges data assimilation

    NASA Astrophysics Data System (ADS)

    Libertino, Andrea; Claps, Pierluigi; Sharma, Ashish; Lakshmi, Venkat

    2016-04-01

    Severe rainfall events are quite common in the coastal areas of the Mediterranean basin during autumn season, despite its generally mild climate. Very often meteorological conditions responsible for these kinds of events are quasi-stationary convective systems, characterized by very localized development, hard to detect with traditional rain gauge networks. In order to improve prediction and management capabilities, progress must be made in understanding the mechanism that govern the development of these kind of precipitation systems at the different scales. Rainfall product from the Tropical Rainfall Measuring Mission (TRMM) are commonly adopted in different branches of the environmental sciences due to the high spatio-temporal resolution and to the quasi-global nature of the data. Building upon the success of TRMM, NASA and JAXA deployed the GPM Core Observatory that, after just two years of activity, seems to allow for great improvement in the accuracy of rainfall products. We developed a methodology aimed at exploiting the timing information derived from high-resolution remote sensing products to analyze the characteristic of severe rainfall systems in the Mediterranean basin. The spatial analysis from satellite, combined with the historical information from the rain gauge network, allows us deepening the knowledge of the spatial extension of extreme rainfall phenomena. All those information, merged together in a hierarchical framework, lead to the definition of Intensity-Duration-Frequency curves "informed" on the nature of the events for each location of the domain, without the need to adopt classical interpolation techniques, unable to represent the complexity of the rainfall systems. The case study refers to a database of daily rainfall measurements extracted from the NOAA GHCN-Daily dataset, recorded during the 20th century by 700 rain gauges distributed in the Mediterranean basin. TRMM and GPM images are used to calibrate the event timing over the

  12. High Spatial Resolution Airborne Multispectral Thermal Infrared Remote Sensing Data for Analysis of Urban Landscape Characteristics

    NASA Technical Reports Server (NTRS)

    Quattrochi, Dale A.; Luvall, Jeffrey C.; Estes, Maurice G., Jr.; Arnold, James E. (Technical Monitor)

    2000-01-01

    We have used airborne multispectral thermal infrared (TIR) remote sensing data collected at a high spatial resolution (i.e., 10m) over several cities in the United States to study thermal energy characteristics of the urban landscape. These TIR data provide a unique opportunity to quantify thermal responses from discrete surfaces typical of the urban landscape and to identify both the spatial arrangement and patterns of thermal processes across the city. The information obtained from these data is critical to understanding how urban surfaces drive or force development of the Urban Heat Island (UHI) effect, which exists as a dome of elevated air temperatures that presides over cities in contrast to surrounding non-urbanized areas. The UHI is most pronounced in the summertime where urban surfaces, such as rooftops and pavement, store solar radiation throughout the day, and release this stored energy slowly after sunset creating air temperatures over the city that are in excess of 2-4'C warmer in contrast with non-urban or rural air temperatures. The UHI can also exist as a daytime phenomenon with surface temperatures in downtown areas of cities exceeding 38'C. The implications of the UHI are significant, particularly as an additive source of thermal energy input that exacerbates the overall production of ground level ozone over cities. We have used the Airborne Thermal and Land Applications Sensor (ATLAS), flown onboard a Lear 23 jet aircraft from the NASA Stennis Space Center, to acquire high spatial resolution multispectral TIR data (i.e., 6 bandwidths between 8.2-12.2 (um) over Huntsville, Alabama, Atlanta, Georgia, Baton Rouge, Louisiana, Salt Lake City, Utah, and Sacramento, California. These TIR data have been used to produce maps and other products, showing the spatial distribution of heating and cooling patterns over these cities to better understand how the morphology of the urban landscape affects development of the UHI. In turn, these data have been used

  13. Effects of remote and in-person verbal interactions on verbalization rates and attention to dynamic spatial scenes.

    PubMed

    Gugerty, Leo; Rakauskas, Mick; Brooks, Johnell

    2004-11-01

    This study focused on how teams allocated attention between a driving-related spatial task and a verbal task, and how different kinds of verbal interactions affected performance of the driving-related task. In Experiment 1, 29 two-person teams performed an interactive verbal task while one team member also performed a simulated driving task. Of the team members performing only the verbal task, half could see their partner's spatial situation, as a car passenger can (in-person condition), and half were remotely located, similar to someone speaking to a driver using a cell-phone. Teams interacted verbally at an overall slower rate during remote than in-person interactions, suggesting that remote verbal interactions are more difficult than in-person interactions. Verbal interactions degraded situation awareness for driving-related information while performing the spatial task; and this degradation was not greater during remote than in-person interactions. Experiment 2 used a faster-paced verbal task and found greater degradation of situation awareness due to the verbal task. These findings are potentially relevant to the issue of how passenger and cell-phone conversations affect driving performance. PMID:15350880

  14. On the effect of spatial variability and support on validation of remote sensing observations of CO2

    NASA Astrophysics Data System (ADS)

    Tadić, Jovan M.; Michalak, Anna M.

    2016-05-01

    Validation of ground-based and satellite remote sensing CO2 observations involves comparisons among platforms and with in situ airborne measurements. Several factors unrelated to observational errors can lead to mismatches between measurements, and must be assessed to avoid misinterpreting actual differences in observed values as errors. Here we explore the impact of CO2 horizontal variability and differences in the spatial support of measurements. Case studies based on flights over Walnut Grove and Petaluma, California, are used to compare hypothetical airborne, TCCON, GOSAT, and OCO-2 measurements. We find that high CO2 variability can lead to differences in inferred XCO2 (1) of over 0.5 ppm between airborne and remote sensing observations, due to the spatial mismatch between spiral flight trajectories and atmospheric columns, and (2) of up to 0.3 ppm among remote sensing platforms, due to differences in the spatial support of observations. Horizontal CO2 variability must therefore be considered in intercomparisons aimed at validation of remote sensing observations.

  15. An Integrated Photogrammetric and Spatial Database Management System for Producing Fully Structured Data Using Aerial and Remote Sensing Images

    PubMed Central

    Ahmadi, Farshid Farnood; Ebadi, Hamid

    2009-01-01

    3D spatial data acquired from aerial and remote sensing images by photogrammetric techniques is one of the most accurate and economic data sources for GIS, map production, and spatial data updating. However, there are still many problems concerning storage, structuring and appropriate management of spatial data obtained using these techniques. According to the capabilities of spatial database management systems (SDBMSs); direct integration of photogrammetric and spatial database management systems can save time and cost of producing and updating digital maps. This integration is accomplished by replacing digital maps with a single spatial database. Applying spatial databases overcomes the problem of managing spatial and attributes data in a coupled approach. This management approach is one of the main problems in GISs for using map products of photogrammetric workstations. Also by the means of these integrated systems, providing structured spatial data, based on OGC (Open GIS Consortium) standards and topological relations between different feature classes, is possible at the time of feature digitizing process. In this paper, the integration of photogrammetric systems and SDBMSs is evaluated. Then, different levels of integration are described. Finally design, implementation and test of a software package called Integrated Photogrammetric and Oracle Spatial Systems (IPOSS) is presented. PMID:22574014

  16. An integrated photogrammetric and spatial database management system for producing fully structured data using aerial and remote sensing images.

    PubMed

    Ahmadi, Farshid Farnood; Ebadi, Hamid

    2009-01-01

    3D spatial data acquired from aerial and remote sensing images by photogrammetric techniques is one of the most accurate and economic data sources for GIS, map production, and spatial data updating. However, there are still many problems concerning storage, structuring and appropriate management of spatial data obtained using these techniques. According to the capabilities of spatial database management systems (SDBMSs); direct integration of photogrammetric and spatial database management systems can save time and cost of producing and updating digital maps. This integration is accomplished by replacing digital maps with a single spatial database. Applying spatial databases overcomes the problem of managing spatial and attributes data in a coupled approach. This management approach is one of the main problems in GISs for using map products of photogrammetric workstations. Also by the means of these integrated systems, providing structured spatial data, based on OGC (Open GIS Consortium) standards and topological relations between different feature classes, is possible at the time of feature digitizing process. In this paper, the integration of photogrammetric systems and SDBMSs is evaluated. Then, different levels of integration are described. Finally design, implementation and test of a software package called Integrated Photogrammetric and Oracle Spatial Systems (IPOSS) is presented. PMID:22574014

  17. Severity of spatial learning impairment in aging: Development of a learning index for performance in the Morris water maze.

    PubMed

    Gallagher, Michela; Burwell, Rebecca; Burchinal, Margaret

    2015-08-01

    The Morris water maze task was originally designed to assess the rat's ability to learn to navigate to a specific location in a relatively large spatial environment. This article describes new measures that provide information about the spatial distribution of the rat's search during both training and probe trial performance. The basic new measure optimizes the use of computer tracking to identify the rat's position with respect to the target location. This proximity measure was found to be highly sensitive to age-related impairment in an assessment of young and aged male Long-Evans rats. Also described is the development of a learning index that provides a continuous, graded measure of the severity of age-related impairment in the task. An index of this type should be useful in correlational analyses with other neurobiological or behavioral measures for the study of individual differences in functional/biological decline in aging. PMID:26214219

  18. Impairment of olfactory, auditory, and spatial serial reversal learning in rats recovered from pyrithiamine-induced thiamine deficiency.

    PubMed

    Mair, R G; Knoth, R L; Rabchenuk, S A; Langlais, P J

    1991-06-01

    Rats that had recovered from pyrithiamine-induced thiamine deficiency (PTD) were compared with controls for spatial, auditory, and olfactory serial reversal learning (SRL); spatial matching to sample (MTS); auditory go-no-go discrimination; and open-field exploration. PTD rats made more errors reaching criterion for SRL in all modalities but showed normal transfer effects between problems. PTD rats were also impaired in learning the go-no-go and MTS tasks and showed consistent alterations in exploratory activity. It is argued that the PTD rat, like human Korsakoff patients, have impairments of learning and memory (but spared capacity for reference memory) that extend across sensory modalities. Postmortem analyses showed normal indices of cortical cholinergic, noradrenergic, dopaminergic, and serotonergic function and consistent bilateral lesions of the thalamus, which were centered on the internal medullary lamina, and the medial mammillary nucleus. PMID:1907457

  19. Cholera in the Lake Kivu region (DRC): Integrating remote sensing and spatially explicit epidemiological modeling

    NASA Astrophysics Data System (ADS)

    Finger, Flavio; Knox, Allyn; Bertuzzo, Enrico; Mari, Lorenzo; Bompangue, Didier; Gatto, Marino; Rodriguez-Iturbe, Ignacio; Rinaldo, Andrea

    2014-07-01

    Mathematical models of cholera dynamics can not only help in identifying environmental drivers and processes that influence disease transmission, but may also represent valuable tools for the prediction of the epidemiological patterns in time and space as well as for the allocation of health care resources. Cholera outbreaks have been reported in the Democratic Republic of the Congo since the 1970s. They have been ravaging the shore of Lake Kivu in the east of the country repeatedly during the last decades. Here we employ a spatially explicit, inhomogeneous Markov chain model to describe cholera incidence in eight health zones on the shore of the lake. Remotely sensed data sets of chlorophyll a concentration in the lake, precipitation and indices of global climate anomalies are used as environmental drivers in addition to baseline seasonality. The effect of human mobility is also modelled mechanistically. We test several models on a multiyear data set of reported cholera cases. The best fourteen models, accounting for different environmental drivers, and selected using the Akaike information criterion, are formally compared via proper cross validation. Among these, the one accounting for seasonality, El Niño Southern Oscillation, precipitation and human mobility outperforms the others in cross validation. Some drivers (such as human mobility and rainfall) are retained only by a few models, possibly indicating that the mechanisms through which they influence cholera dynamics in the area will have to be investigated further.

  20. Age-related changes in rostral basal forebrain cholinergic and GABAergic projection neurons: Relationship with spatial impairment

    PubMed Central

    Bañuelos, C.; LaSarge, C. L.; McQuail, J. A.; Hartman, J. J.; Gilbert, R. J.; Ormerod, B. K.; Bizon, J. L.

    2013-01-01

    Both cholinergic and GABAergic projections from the rostral basal forebrain have been implicated in hippocampal function and mnemonic abilities. While dysfunction of cholinergic neurons has been heavily implicated in age-related memory decline, significantly less is known regarding how age-related changes in co-distributed GABAergic projection neurons contribute to a decline in hippocampal-dependent spatial learning. In the current study, confocal stereology was used to quantify cholinergic (choline acetyltransferase (ChAT) immunopositive) neurons, GABAergic projection (glutamic decarboxylase 67 (GAD67) immunopositive) neurons, and total (NeuN immunopositive) neurons in the rostral basal forebrain of young and aged rats that were first characterized on a spatial learning task. ChAT immunopositive neurons were significantly but modestly reduced in aged rats. Although ChAT immunopositive neuron number was strongly correlated with spatial learning abilities among young rats, the reduction of ChAT immunopositive neurons was not associated with impaired spatial learning in aged rats. In contrast, the number of GAD67 immunopositive neurons was robustly and selectively elevated in aged rats that exhibited impaired spatial learning. Interestingly, the total number of rostral basal forebrain neurons was comparable in young and aged rats, regardless of their cognitive status. These data demonstrate differential effects of age on phenotypically distinct rostral basal forebrain projection neurons, and implicate dysregulated cholinergic and GABAergic septohippocampal circuitry in age-related mnemonic decline. PMID:22817834

  1. Remote sensing and spatial statistical analysis to predict the distribution of Oncomelania hupensis in the marshlands of China.

    PubMed

    Zhang, Zhi-Ying; Xu, De-Zhong; Zhou, Xiao-Nong; Zhou, Yun; Liu, Shi-Jun

    2005-01-01

    Remote sensing and spatial statistical analysis were employed to predict the distribution of Oncomelania hupensis, the intermediate host snail of Schistosoma japonicum, in the marshlands of Jiangning county in China. Surrogate indices related to environmental factors in the marshlands were derived from a Landsat 7 ETM+ image, and the relationship between environmental covariates and the density of O. hupensis was analyzed by stepwise regression models and ordinary kriging. Although stepwise regression demonstrated that O. hupensis densities of live snails in the marshlands related significantly to the modified soil-adjusted vegetation index, wetness and land surface temperature, the correlation coefficient was low (0.282). Therefore, spatial patterns of the regression residual were investigated by the semi-variogram method, and the spatial variation of O. hupensis density attributed to the spatial autocorrelation was estimated by ordinary kriging. The regression model of the snail density and ordinary kriging of its spatial variation were then combined with the aim of improving the prediction of O. hupensis. Following this approach, the prediction indeed improved considerably (0.852). Our results show that it is possible to predict the distribution of O. hupensis in these marshlands by using remotely sensed environmental indices, and that spatial statistical analyses are capable of improving prediction accuracy. These findings are of relevance for mapping and prediction of schistosomiasis japonica in China, and hence the national control programme. PMID:16150415

  2. a Kernel Method Based on Topic Model for Very High Spatial Resolution (vhsr) Remote Sensing Image Classification

    NASA Astrophysics Data System (ADS)

    Wu, Linmei; Shen, Li; Li, Zhipeng

    2016-06-01

    A kernel-based method for very high spatial resolution remote sensing image classification is proposed in this article. The new kernel method is based on spectral-spatial information and structure information as well, which is acquired from topic model, Latent Dirichlet Allocation model. The final kernel function is defined as K = u1Kspec + u2Kspat + u3Kstru, in which Kspec, Kspat, Kstru are radial basis function (RBF) and u1 + u2 + u3 = 1. In the experiment, comparison with three other kernel methods, including the spectral-based, the spectral- and spatial-based and the spectral- and structure-based method, is provided for a panchromatic QuickBird image of a suburban area with a size of 900 × 900 pixels and spatial resolution of 0.6 m. The result shows that the overall accuracy of the spectral- and structure-based kernel method is 80 %, which is higher than the spectral-based kernel method, as well as the spectral- and spatial-based which accuracy respectively is 67 % and 74 %. What's more, the accuracy of the proposed composite kernel method that jointly uses the spectral, spatial, and structure information is highest among the four methods which is increased to 83 %. On the other hand, the result of the experiment also verifies the validity of the expression of structure information about the remote sensing image.

  3. ABT-724 alleviated hyperactivity and spatial learning impairment in the spontaneously hypertensive rat model of attention-deficit/hyperactivity disorder.

    PubMed

    Yin, Ping; Cao, Ai-Hua; Yu, Lin; Guo, Liang-Jing; Sun, Ruo-Peng; Lei, Ge-Fei

    2014-09-19

    Dysfunction of dopamine D4 receptor (D4R) is linked to attention-deficit/hyperactivity disorder (ADHD) as well as ADHD associated cognitive impairment. Here, we tested the possible therapeutic benefit of the D4R-selective agonist ABT-724 in adolescent spontaneously hypertensive rats (SHRs). ABT-724-treated SHRs were administered ABT-724 (0.04mg/kg, 0.16mg/kg or 0.64mg/kg) from postnatal day (P) 28 to P32. Control SHRs and Sprague-Dawley (SD) rats were injected with saline. Then two cohorts of rats were tested in the open field and Làt maze that measured locomotion and non-selective attention (NSA), respectively. Another cohort of rats was subjected to water maze task for evaluation of spatial learning and memory. We found that control SHRs displayed hyperactivity as well as impaired NSA and spatial learning compared with normotensive SD rats. ABT-724 (0.16 and 0.64mg/kg) treatment alleviated hyperactivity and spatial learning impairment in SHRs. No dose of ABT-724 tested altered NSA in SHRs. Our results raise the possibility that ABT-724 may be used as a therapeutic intervention for ADHD patients during adolescence. PMID:25128216

  4. Impairments in precision, rather than spatial strategy, characterize performance on the virtual Morris Water Maze: A case study.

    PubMed

    Kolarik, Branden S; Shahlaie, Kiarash; Hassan, Abdul; Borders, Alyssa A; Kaufman, Kyle C; Gurkoff, Gene; Yonelinas, Andy P; Ekstrom, Arne D

    2016-01-01

    Damage to the medial temporal lobes produces profound amnesia, greatly impairing the ability of patients to learn about new associations and events. While studies in rodents suggest a strong link between damage to the hippocampus and the ability to navigate using distal landmarks in a spatial environment, the connection between navigation and memory in humans remains less clear. Past studies on human navigation have provided mixed findings about whether patients with damage to the medial temporal lobes can successfully acquire and navigate new spatial environments, possibly due, in part, to issues related to patient demographics and characterization of medial temporal lobe damage. Here, we report findings from a young, high functioning patient who suffered severe medial temporal lobe damage. Although the patient is densely amnestic, her ability to acquire and utilize new, but coarse, spatial "maps" appears largely intact. Specifically, a novel computational analysis focused on the precision of her spatial search revealed a significant deficit in spatial precision rather than spatial search strategy. These findings argue that an intact hippocampus in humans is not necessary for representing multiple external landmarks during spatial navigation of new environments. We suggest instead that the human hippocampus may store and represent complex high-resolution bindings of features in the environment as part of a larger role in perception, memory, and navigation. PMID:26593960

  5. Doxorubicin and cyclophosphamide lead to long-lasting impairment of spatial memory in female, but not male mice.

    PubMed

    Philpot, Rex M; Ficken, Melissa; Wecker, Lynn

    2016-07-01

    Self-reports of chemotherapy-related cognitive deficits (CRCDs) are more prevalent among women than men, suggesting that women may be more vulnerable to the cognitive-impairing effects of chemotherapy. However, there have been no direct comparisons of females and males using objective measures of cognitive function either during or following exposure to the same chemotherapeutic regimen. The present study used an animal model, and a prospective longitudinal design, to assess sex differences in the manifestation and persistence of spatial memory deficits resulting from exposure to doxorubicin (DOX) and cyclophosphamide (CYP), commonly used anticancer drugs. The spatial memory of female and male BALB/C mice was assessed using the Morris water maze prior to, during and following 4 weekly intravenous injections of DOX (2.5mg/kg) and CYP (25mg/kg) or vehicle. Females receiving DOX+CYP experienced significant deficits in spatial memory during and following injections when compared to baseline or females receiving vehicle. These deficits persisted for at least 34 days following the final injection. In contrast, males receiving DOX+CYP injections did not exhibit alterations in spatial memory relative to baseline or males receiving vehicle. These findings indicate that females may be more vulnerable than males to the cognitive-impairing effects of DOX+CYP and demonstrate that deficits in females persist for at least several weeks following drug exposure. Preclinical studies of CRCDs should parallel clinical work by including females and examine sex specific factors as potential mechanisms. PMID:27083301

  6. Rhinal and Dorsolateral Prefrontal Cortex Lesions Produce Selective Impairments in Object and Spatial Learning and Memory in Canines

    PubMed Central

    Christie, Lori-Ann; Saunders, Richard C.; Kowalska, Danuta, M.; MacKay, William A.; Head, Elizabeth; Cotman, Carl W.; Milgram, Norton W.

    2014-01-01

    To examine the effects of rhinal and dorsolateral prefrontal cortex lesions on object and spatial recognition memory in canines, we used a protocol in which both an object (delayed non-matching to sample, or DNMS) and a spatial (delayed non-matching to position or DNMP) recognition task were administered daily. The tasks used similar procedures such that only the type of stimulus information to be remembered differed. Rhinal cortex (RC) lesions produced a selective deficit on the DNMS task, both in retention of the task rules at short delays and in object recognition memory. By contrast, performance on the DNMP task remained intact at both short and long delay intervals in RC animals. Subjects who received dorsolateral prefrontal cortex (dlPFC) lesions were impaired on a spatial task at a short, 5-sec delay, suggesting disrupted retention of the general task rules, however, this impairment was transient; long-term spatial memory performance was unaffected in dlPFC subjects. The present results provide support for the involvement of the RC in object, but not visuospatial, processing and recognition memory, whereas the dlPFC appears to mediate retention of a non-matching rule. These findings support theories of functional specialization within the medial temporal lobe and frontal cortex and suggest that rhinal and dorsolateral prefrontal cortices in canines are functionally similar to analogous regions in other mammals. PMID:18792072

  7. Into the environment of mosquito-borne disease: A spatial analysis of vector distribution using traditional and remotely sensed methods

    NASA Astrophysics Data System (ADS)

    Brown, Heidi E.

    Spatially explicit information is increasingly available for infectious disease modeling. However, such information is reluctantly or inappropriately incorporated. My dissertation research uses spatially explicit data to assess relationships between landscape and mosquito species distribution and discusses challenges regarding accurate predictive risk modeling. The goal of my research is to use remotely sensed environmental information and spatial statistical methods to better understand mosquito-borne disease epidemiology for improvement of public health responses. In addition to reviewing the progress of spatial infectious disease modeling, I present four research projects. I begin by evaluating the biases in surveillance data and build up to predictive modeling of mosquito species presence. In the first study I explore how mosquito surveillance trap types influence estimations of mosquito populations. Then. I use county-based human surveillance data and landscape variables to identify risk factors for West Nile virus disease. The third study uses satellite-based vegetation indices to identify spatial variation among West Nile virus vectors in an urban area and relates the variability to virus transmission dynamics. Finally, I explore how information from three satellite sensors of differing spatial and spectral resolution can be used to identify and distinguish mosquito habitat across central Connecticut wetlands. Analyses presented here constitute improvements to the prediction of mosquito distribution and therefore identification of disease risk factors. Current methods for mosquito surveillance data collection are labor intensive and provide an extremely limited, incomplete picture of the species composition and abundance. Human surveillance data offers additional challenges with respect to reporting bias and resolution, but is nonetheless informative in identifying environmental risk factors and disease transmission dynamics. Remotely sensed imagery supports

  8. Snow Depth Spatial Distribution Using Microwave Remote Sensing at the Puna Tsang River Basin in Bhutan

    NASA Astrophysics Data System (ADS)

    Duran-Ballen, S.; Tsutsui, H.; Koike, T.

    2012-12-01

    Spatial distribution of snow amount derived from satellite observations has been previously achieved for flat region. But for mountainous regions, spatial distribution of snow amount has not been addressed because remote sensing instruments are very sensitive to the effect of the terrain slope; and because there is no available data for validation. This study focuses on the estimation of snow amount using a microwave radiative transfer model (RTM) in mountain region. AMSR-E satellite observations of brightness temperature (Tb) at 18.7GHz and 36.5GHz frequencies are compared to calculated values of Tb in Lookup Tables generated by the RTM model. The model uses a snow algorithm to derive the snow depth and temperature spatial distribution over the target region. This snow algorithm has been previously validated in a flat region using in-situ recorded snow-depth data. In this study, the local slope in mountainous terrain, where the local incidence angle is different than the 55 degree incidence angle from the satellite, is taken into account. The local incidence angle is calculated from the scalar product between the radiometer scanning vector and the surface normal vector of the local slope. The terrain DEM is used to calculate the slope and aspect of each terrain grid. Then, with the geolocation of the satellite as it passes over, the local incidence angle is computed. AMSR-E data resolution is about 25x25 km but at this resolution we can not meaningfully express the topographic terrain. Therefore, a DEM resolution of 1x1 km is used. To overcome the difference of spatial resolution between the satellite observation and the terrain grid, the approach is to estimate the Tb for the 18.7GHz and 36.5GHz frequencies with the local incidence angle for each terrain grid. Then, an averaged Tb for each footprint is computed from the weighted average of the Tb of each terrain grid based on the count of occurrence of the same local incidence angle. Then, the averaged Tb is

  9. Low spatial resolution remote sensing data validation over the Valencia and Alacant Anchor Stations

    NASA Astrophysics Data System (ADS)

    Velazquez Blazquez, Almudena; Asensi, Sandra; Clerbaux, Nicolas; Coll, Amparo; Dewitte, Steven; Estelles Leal, Victor; Geraldo Ferreira, A.; Gonzalez Sotelino, Luis; Miro, Jose Vicente; Monsoriu, Almudena; Priestley, Kory; Rius, Antonio; Smith, G. Louis; Szewczyk, Z. Peter; Josep, Torrobella; Lopez-Baeza, Ernesto

    In this study we present the review of the comparisons between top of the atmosphere (TOA) broadband radiances and fluxes measured by the Geostationary Earth Radiation Budget (GERB-1) instrument on board Meteosat-9 satellite and those measured by the Clouds and the Earth's Radiant Energy System (CERES) instrument, on board Terra-FM2 satellite, with equivalent ra-diances and fluxes obtained from radiative transfer simulations with ocassion of several ground validation campaigns. The simulations are based on measured atmospheric and surface data gathered during the campaigns at the Valencia and Alacant Anchor Stations areas (VAS and AAS) between February 2004 and November 2008. The Anchor Stations are automatic meteorological stations which aim to help validation studies of low-spatial resolution remote sensing data. They are equipped with instruments to measure air temperature and humidity at different levels, pressure, wind speed and direction, down-welling and upwelling shortwave (SW) and longwave (LW) fluxes, soil moisture, soil heat flux and soil temperature at different depths. In addition to the station data, ancillary data has been used for the simulations, such as, in situ radiosoundings in the case of the VAS field campaigns, and radiosoundings from the Spanish State Meteorological Station of Murcia ( 50 km from the study area in the case of AAS), in-situ measurements of Global Positioning System (GPS) for the retrieval precipitable water vapor content, CIMEL and EKO sunphotometer measurements to derive aerosol optical thickness and diffuse shortwave radiation from Eppley automatic solar tracker (only for AAS validation). Satellite-based data are also used in the study, such as the Total Ozone Mapping Spectrometer (TOMS) Ozone values over the area, CERES/SARB (Surface and Atmospheric Radiation Budget) emissivity maps, and Bidirectional Reflectances of the surface derived from MODIS (Moderate Resolution Imaging Spectroradiometer) MOD43 BRDF product. The

  10. Improvements in Virtual Sensors: Using Spatial Information to Estimate Remote Sensing Spectra

    NASA Technical Reports Server (NTRS)

    Oza, Nikunj C.; Srivastava, Ashok N.; Stroeve, Julienne

    2005-01-01

    Various instruments are used to create images of the Earth and other objects in the universe in a diverse set of wavelength bands with the aim of understanding natural phenomena. Sometimes these instruments are built in a phased approach, with additional measurement capabilities added in later phases. In other cases, technology may mature to the point that the instrument offers new measurement capabilities that were not planned in the original design of the instrument. In still other cases, high resolution spectral measurements may be too costly to perform on a large sample and therefore lower resolution spectral instruments are used to take the majority of measurements. Many applied science questions that are relevant to the earth science remote sensing community require analysis of enormous amounts of data that were generated by instruments with disparate measurement capabilities. In past work [1], we addressed this problem using Virtual Sensors: a method that uses models trained on spectrally rich (high spectral resolution) data to "fill in" unmeasured spectral channels in spectrally poor (low spectral resolution) data. We demonstrated this method by using models trained on the high spectral resolution Terra MODIS instrument to estimate what the equivalent of the MODIS 1.6 micron channel would be for the NOAA AVHRR2 instrument. The scientific motivation for the simulation of the 1.6 micron channel is to improve the ability of the AVHRR2 sensor to detect clouds over snow and ice. This work contains preliminary experiments demonstrating that the use of spatial information can improve our ability to estimate these spectra.

  11. Organohalogen emissions from saline environments - spatial extrapolation using remote sensing as most promising tool

    NASA Astrophysics Data System (ADS)

    Kotte, K.; Löw, F.; Huber, S. G.; Krause, T.; Mulder, I.; Schöler, H. F.

    2012-03-01

    Due to their negative water budget most recent semi-/arid regions are characterized by vast evaporates (salt lakes and salty soils). We recently identified those hyper-saline environments as additional sources for a multitude of volatile halogenated organohalogens (VOX). These compounds can affect the ozone layer of the stratosphere and play a key role in the production of aerosols. A remote sensing based analysis was performed in the Southern Aral Sea basin, providing information of major soil types as well as their extent and spatial and temporal evolution. VOX production has been determined in dry and moist soil samples after 24 h. Several C1- and C2 organohalogens have been found in hyper-saline topsoil profiles, including CH3Cl, CH3Br, CHBr3 and CHCl3. The range of organohalogens also includes trans-1,2-dichloroethene (DCE), which is reported here to be produced naturally for the first time. Using MODIS time series and supervised image classification a daily production rate for DCE has been calculated for the 15 000 km2 ranging research area in the southern Aralkum. The applied laboratory setup simulates a short-term change in climatic conditions, starting from dried-out saline soil that is instantly humidified during rain events or flooding. It describes the general VOX production potential, but allows only for a rough estimation of resulting emission loads. VOX emissions are expected to increase in the future since the area of salt affected soils is expanding due to the regressing Aral Sea. Opportunities, limits and requirements of satellite based rapid change detection and salt classification are discussed.

  12. Investigating the Spatial Characteristics of Forest Fire in North Korea using Remote Sensing and GIS

    NASA Astrophysics Data System (ADS)

    RI, J.; Lee, K. S.

    2015-12-01

    Forest fires cause billions of dollar damage to property and the environment in the world every year. In North Korea (NK) forest fire occurred frequently in the entire region with the exception of the western plains and massive forest fires broke out throughout NK in May 2004. Furthermore, few researches focused on NK forest fire because of data unavailability and inaccessibility to the region. Operational fire monitoring over large areas can be approached through satellite remote sensing (RS). Thus, it is necessary to investigate the area damaged by forest fire and get information of damaged area for restoration of forest in NK after reunification. Therefore, the purpose of this study is to identify the location of forest fire and to estimate the damaged area by forest fire and finally to detect the landscape change after forest fire in Gangwon and South Hamgyong Province, NK using satellite RS data. In this study, we will investigate the area damaged by forest fire and investigate the spatial characteristics of forest fire in Gangwon and South Hamgyong Province using RS. Landsat data from USGS Were preprocessed (band composition), NBR and dNBR are calculated for figuring out the burned area and investigating the burn severity (BS) in burned area. NBR and dNBR (differenced NBR) are mostly useful to estimate BS by forest fires damage from RS data. The dNBR was then calculated by subtracting the post-fire NBR from the pre-fire NBR: The burned area from Landsat data processing were stored in GIS database to be retrieved and analyzed to figure out the chronological change pattern of forest fire damaged area. Finally, the spatiotemporal characteristics of forest fire in NK were analyzed and discussed to provide the information for restoring forest fire damaged area after reunification.

  13. Evidence for Synchronicity of Lightning Activity in Spatially Remote Thunderstorms Obtained from Space Shuttle Observations

    NASA Astrophysics Data System (ADS)

    Yair, Y.; Aviv, R.; Ravid, G.; Yaniv, R.; Ziv, B.; Price, C.

    2005-12-01

    Visual observations by space shuttle astronauts detailed a phenomenon in which spatially distant thunderstorm cells seemed to reciprocally "ignite" lightning flashes in a semi-cyclic sequence. We report the quantitative analysis of lightning observations conducted within the framework of the MEIDEX-sprite campaign on board the space shuttle Columbia in January 2003 [Yair et al., 2003]. We analyzed video footage of 6 storm systems with varying flash rates, which occurred over Africa, South America, Australia and the Pacific Ocean. It is found that when the storm flash rate was high, lightning activity in horizontally remote electrically active cells became clustered, with bursts of nearly simultaneous activity separated by periods of quiet. The recurrence time was ~2.5 seconds, close to the time delay between consecutive signals in the SR range previously reported [Fallekrug, 1995]. We propose that this behavior is similar to the collective dynamics of a network of weakly coupled limit-cycle oscillators [Strogatz, 2000]. Thunderstorm cells embedded within a mesoscale convective system (MCS) constitute such a network, and their lightning frequency is best described in terms of phase-locking of a globally coupled array [Kourtchatov et al., 1995]. The dominant network hub in such an MCS is the thunderstorm cell with the highest flash rate, which affects the lightning activity of neighboring cells. Comparison of basic parameters of the lightning network with predictions of random graph models reveals that the network cannot be described by the classical random graph model [Erdos and Renyi, 1960], but is more compatible with generalized random graphs with prescribed degree distribution [Newman et al., 2001] that exhibit a high clustering coefficient and small average path lengths. Such networks are capable of supporting fast response, synchronization and coherent oscillations. Several physical mechanisms are suggested to explain this phenomenon.

  14. Monitoring the Environment using High-Spatial Resolution Remote Sensing: Contribution to Health Information Systems

    NASA Astrophysics Data System (ADS)

    Tourre, Y. M.; Lacaux, J.

    2007-12-01

    Presence (density) of mosquitoes linked to Rift Valley Fever (RVF) epidemics in the Ferlo (Senegal) is evaluated by monitoring the environment from space. Using five SPOT-5 high-resolution images (~10m spatial resolution, on August 17th, 2006) a meridional transect of 290 x 60 km2 is analyzed for the first time. Four major ecozones are thus identified: Senegal River valley; sandy Ferlo; sandy-clayey Ferlo; and steppe/cultivated areas, from north to south, respectively. An integrated/multidisciplinary approach using remote-sensing leads to a composited Zones Potentially Occupied by Mosquitoes (or ZPOMs, with extrema). It is found that at the peak of the rainy season, the area occupied by ponds is of 12,817 ha ± 10% (i.e., ~ 0.8 % of the transect) with a mean ZPOM 17 times larger i.e.: 212,813 ha ± 10 % (or ~14 % of the transect). ZPOMs characteristics (minimum and maximum) at the ecozones levels with different hydrological mechanisms, are presented. Ponds and ZPOMs inter-annual variabilities and RVF risks, are subsequently highlighted by comparing statistics in the so-called Barkedji zone (sandy-clayey Ferlo with a hydrofossil riverbed), for the very humid year of 2003, and the near normal rainfall year of 2006. It is shown that at the end of August 2003/2006, ponds (ZPOMs) areas, were already ~22 (~5) times larger. The key roles played by isolated ponds for animals' exposure to RVF risks are thus identified. These results highlight the importance of monitoring the changing environment when linkages with public health exist. The ZPOM approach is to be adapted for other vector-borne diseases such as malaria, dengue fever, in different places of the world. Results are meant to be included into Health Information Systems (HIS) on an operational basis, in order to minimize socio-economical impacts from epidemics.

  15. Remote sensing-based quantification of spatial variation in canopy phenology of four dominant tree species in Europe

    NASA Astrophysics Data System (ADS)

    Han, Qifei; Luo, Geping; Li, Chaofan

    2013-01-01

    Spatial variation of phenology is a central feature of global change research. Satellite remote sensing is used for continental to global monitoring due to the limitations of long-term field observations of plant phenology. A threshold method was used to estimate the start of the season, length of the season, maximum normalized difference vegetation index (NDVI), and integral NDVI for selected tree species using remote sensing based NDVI data acquired by the VEGETATION instrument on board Satellite Pour l'Observation de la Terre (SPOT VGT NDVI). Afterward, the spatial patterns in the satellite-derived phenological metrics for four dominant tree species (i.e., beech, birch, pine, and spruce) across Europe were characterized. The results indicate that: (1) The SOS occurs 1.6-2.9 days later and the average LOS is 2.7-3 days shorter per 1 deg of latitude increase from south to north. (3) The SOS occurs 0.7-1.8 days later and the LOS was 0.6-2 days shorter per 100-m increase in altitude for the four species. (4) The SOS and LOS across Europe are well correlated with the mean annual air temperature (1°C correlates with a 4.5-day advance in the SOS and a 7-day extension in the LOS). Our research is the first one to characterize the spatial and temporal variations of phenology for different tree species across Europe using remote sensing.

  16. Thiamine deficiency decreases glutamate uptake in the prefrontal cortex and impairs spatial memory performance in a water maze test.

    PubMed

    Carvalho, Fabiana M; Pereira, Silvia R C; Pires, Rita G W; Ferraz, Vany P; Romano-Silva, Marco Aurélio; Oliveira-Silva, Ieda F; Ribeiro, Angela M

    2006-04-01

    Using an animal model of Wernicke-Korsakoff syndrome, in which rats were submitted to a chronic ethanol treatment with or without a thiamine deficiency episode, the glutamate uptake in the prefrontal cortex and spatial memory aspects were studied. It was found that (i) thiamine deficiency, but not chronic ethanol consumption, induced a significant decrease of glutamate uptake; (ii) thiamine-deficient subjects showed an impaired performance in the water maze spatial memory test though these animals were able to learn the task during the acquisition. In spite of the fact that thiamine deficiency affects both glutamate uptake and spatial reference memory, there was no significant correlation between these two data. The present results show that, although prefrontal cortex is considered by some authors a not vulnerable area to lesions caused by thiamine deficiency, this vitamin deficiency does cause a neurochemistry dysfunction in that region. PMID:16687165

  17. A new coumarin derivative, IMM-H004, attenuates okadaic acid-induced spatial memory impairment in rats

    PubMed Central

    Song, Xiu-yun; Wang, Ying-ying; Chu, Shi-feng; Hu, Jin-feng; Yang, Peng-fei; Zuo, Wei; Song, Lian-kun; Zhang, Shuai; Chen, Nai-hong

    2016-01-01

    Aim: A novel coumarin derivative 7-hydroxy-5-methoxy-4-methyl-3-(4-methylpiperazin-1-yl)-coumarin (IMM-H004) has shown anti-apoptotic, anti-inflammatory and neuroprotective activities. In this study we investigated the effects of IMM-H004 on spatial memory in rats treated with okadaic acid (OKA), which was used to imitate Alzheimer's disease (AD)-like symptoms. Methods: SD rats were administered IMM-H004 (8 mg·kg−1·d−1, ig) or donepezil (positive control, 1 mg·kg−1·d−1, ig) for 25 d. On d 8 and 9, OKA (200 ng) was microinjected into the right ventricle. Morris water maze test was used to evaluate the spatial memory impairments. Tau and β-amyloid (Aβ) pathology in the hippocampus was detected using Western blot and immunohistochemistry. TUNEL staining was used to detect cell apoptosis. Results: OKA-treated rats showed significant impairments of spatial memory in Morris water maze test, which were largely reversed by administration of IMM-H004 or donepezil. Furthermore, OKA-treated rats exhibited significantly increased phosphorylation of tau, deposits of Aβ protein and cell apoptosis in the hippocampus, which were also reversed by administration of IMM-H004 or donepezil. Conclusion: Administration of IMM-H004 or donepezil protects rats against OKA-induced spatial memory impairments via attenuating tau or Aβ pathology. Thus, IMM-H004 may be developed as a therapeutic agent for the treatment of AD. PMID:26838073

  18. Hippocampal Gene Expression Meta-Analysis Identifies Aging and Age-Associated Spatial Learning Impairment (ASLI) Genes and Pathways

    PubMed Central

    Uddin, Raihan K.; Singh, Shiva M.

    2013-01-01

    A number of gene expression microarray studies have been carried out in the past, which studied aging and age-associated spatial learning impairment (ASLI) in the hippocampus in animal models, with varying results. Data from such studies were never integrated to identify the most significant ASLI genes and to understand their effect. In this study we integrated these data involving rats using meta-analysis. Our results show that proper removal of batch effects from microarray data generated from different laboratories is necessary before integrating them for meta-analysis. Our meta-analysis has identified a number of significant differentially expressed genes across age or across ASLI. These genes affect many key functions in the aged compared to the young rats, which include viability of neurons, cell-to-cell signalling and interaction, migration of cells, neuronal growth, and synaptic plasticity. These functional changes due to the altered gene expression may manifest into various neurodegenerative diseases and disorders, some of which leading into syndromic memory impairments. While other aging related molecular changes can result into altered synaptic plasticity simply causing normal aging related non-syndromic learning or spatial learning impairments such as ASLI. PMID:23874995

  19. Use of High Spatial Resolution Remote Sensing for Hydro-Geomorphologic Analysis of Medium-sized Arid Basins

    NASA Astrophysics Data System (ADS)

    Sadeh, Yuval; Blumberg, Dan G.; Cohen, Hai; Morin, Efrat; Maman, Shimrit

    2016-04-01

    Arid environments are often remote, expansive, difficult to access and especially vulnerable to flash flood hazards due to the poor understanding of the phenomenon and the lack of meteorological, geomorphological, and hydrological data. For many years, catchment characteristics have been observed using point-based measurements such as rain gauges and soil sample analysis; on the other hand, use of remote sensing technologies can provide spatially continuous hydrological parameters and variables. The advances in remote sensing technologies can provide new geo-spatial data using high spatial and temporal resolution for basin-scale geomorphological analysis and hydrological models. This study used high spatial resolution remote sensing for hydro-geomorphologic analysis of the arid medium size Rahaf watershed (76 km2), located in the Judean Desert, Israel. During the research a high resolution geomorphological map of Rahaf basin was created using WorldView-2 multispectral satellite imageries; surface roughness was estimated using SIR-C and COSMO-SkyMed Synthetic Aperture Radar (SAR) spaceborne sensors; and rainstorm characteristics were extracted using ground-based meteorological radar. The geomorphological mapping of Rahaf into 17 classes with good accuracy. The surface roughness extraction using SAR over the basin showed that the correlation between the COSMO-SkyMed backscatter coefficient and the surface roughness was very strong with an R2 of 0.97. This study showed that using x-band spaceborne sensors with high spatial resolution, such as COSMO-SkyMed, are more suitable for surface roughness evaluation in flat arid environments and should be in favor with longer wavelength operating sensors such as the SIR-C. The current study presents an innovative method to evaluate Manning's hydraulic roughness coefficient (n) in arid environments using radar backscattering. The weather radar rainfall data was calibrated using rain gauges located in the watershed. The

  20. Spatial Navigation in Complex and Radial Mazes in APP23 Animals and Neurotrophin Signaling as a Biological Marker of Early Impairment

    ERIC Educational Resources Information Center

    Hellweg, Rainer; Huber, Roman; Kuhl, Alexander; Riepe, Matthias W.; Lohmann, Peter

    2006-01-01

    Impairment of hippocampal function precedes frontal and parietal cortex impairment in human Alzheimer's disease(AD). Neurotrophins are critical for behavioral performance and neuronal survival in AD. We used complex and radial mazes to assess spatial orientation and learning in wild-type and B6-Tg(ThylAPP)23Sdz (APP23) animals, a transgenic mouse…

  1. Estimation of crops biomass and evapotranspiration from high spatial and temporal resolutions remote sensing data

    NASA Astrophysics Data System (ADS)

    Claverie, Martin; Demarez, Valérie; Duchemin, Benoît.; Ceschia, Eric; Hagolle, Olivier; Ducrot, Danielle; Keravec, Pascal; Beziat, Pierre; Dedieu, Pierre

    2010-05-01

    Carbon and water cycles are closely related to agricultural activities. Agriculture has been indeed identified by IPCC 2007 report as one of the options to sequester carbon in soil. Concerning the water resources, their consumptions by irrigated crops are called into question in view of demographic pressure. In the prospect of an assessment of carbon production and water consumption, the use of crop models at a regional scale is a challenging issue. The recent availability of high spatial resolution (10 m) optical sensors associated to high temporal resolution (1 day) such as FORMOSAT-2 and, in the future, Venµs and SENTINEL-2 will offer new perspectives for agricultural monitoring. In this context, the objective of this work is to show how multi-temporal satellite observations acquired at high spatial resolution are useful for a regional monitoring of following crops biophysical variables: leaf area index (LAI), aboveground biomass (AGB) and evapotranspiration (ET). This study focuses on three summer crops dominant in South-West of France: maize, sunflower and soybean. A unique images data set (82 FORMOSAT-2 images over four consecutive years, 2006-2009) was acquired for this project. The experimental data set includes LAI and AGB measurements over eight agricultural fields. Two fields were intensively monitored where ET flux were measured with a 30 minutes time step using eddy correlation methods. The modelisation approach is based on FAO-56 method coupled with a vegetation functioning model based on Monteith theory: the SAFY model [5]. The model operates at a daily time step model to provide estimates of plant characteristics (LAI, AGB), soil conditions (soil water content) and water use (ET). As a key linking variable, LAI is deduced from FORMOSAT-2 reflectances images, and then introduced into the SAFY model to provide spatial and temporal estimates of these biophysical variables. Most of the SAFY parameters are crop related and have been fixed according to

  2. Impairment of exploratory behavior and spatial memory in adolescent rats in lithium-pilocarpine model of temporal lobe epilepsy.

    PubMed

    Kalemenev, S V; Zubareva, O E; Frolova, E V; Sizov, V V; Lavrentyeva, V V; Lukomskaya, N Ya; Kim, K Kh; Zaitsev, A V; Magazanik, L G

    2015-01-01

    Cognitive impairment in six-week -old rats has been studied in the lithium-pilocarpine model of adolescent temporal lobe epilepsy in humans. The pilocarpine-treated rats (n =21) exhibited (a) a decreased exploratory activity in comparison with control rats (n = 20) in the open field (OP) test and (b) a slower extinction of exploratory behavior in repeated OP tests. The Morris Water Maze (MWM) test showed that the effect of training was less pronounced in the pilocarpine-treated rats, which demonstrated disruption of predominantly short-term memory. Therefore, our study has shown that lithium-pilocarpine seizures induce substantial changes in exploratory behavior and spatial memory in adolescent rats. OP and MWM tests can be used in the search of drugs reducing cognitive impairments associated with temporal lobe epilepsy. PMID:26335964

  3. Amygdala kindling-induced seizures selectively impair spatial memory. 2. Effects on hippocampal neuronal and glial muscarinic acetylcholine receptor.

    PubMed

    Beldhuis, H J; Everts, H G; Van der Zee, E A; Luiten, P G; Bohus, B

    1992-10-01

    The muscarinic acetylcholine receptor is linked via hydrolysis of phosphoinositides to the protein kinase C pathway. In a preceding paper (Beldhuis, H. J. A., H. G. J. Everts, E. A. Vander Zee, P. G. M. Luiten, and B. Bohus (1992) Amygdala kindling-induced seizures selectively impair spatial memory. 1. Behavioral characteristics and effects on hippocampal neuronal protein kinase C isoforms. Hippocampus 2:397-410), the role of different isoforms of protein kinase C in neurobiological processes associated with plasticity was studied using both a spatial learning paradigm and amygdala kindling in the rat. This study extended the findings on protein kinase C activity to the level of the muscarinic acetylcholine receptor. Rats were trained in a spatial learning paradigm and kindled simultaneously in the amygdala to develop generalized motor convulsions. Control rats were trained only in the spatial learning paradigm to acquire stable working and reference memory performance. Alteration in the expression of the muscarinic acetylcholine receptor was investigated using a monoclonal antibody to muscarinic acetylcholine receptor proteins. Trained control rats that were exposed repeatedly to the spatial learning paradigm showed an increase in immunoreactivity for the muscarinic acetylcholine receptor located in the same hippocampal regions in which the protein kinase C activity was increased. In fully kindled rats, however, this increase located in principal neurons was absent, whereas expression of muscarinic acetylcholine receptor proteins was increased in hippocampal astrocytes. Moreover, fully kindled rats showed an impairment in reference memory performance as compared to trained control rats.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1308197

  4. Noisy galvanic vestibular stimulation enhances spatial memory in cognitive impairment-induced by intracerebroventricular-streptozotocin administration.

    PubMed

    Adel Ghahraman, Mansoureh; Zahmatkesh, Maryam; Pourbakht, Akram; Seifi, Behjat; Jalaie, Shohreh; Adeli, Soheila; Niknami, Zohreh

    2016-04-01

    There are several anatomical connections between vestibular system and brain areas construct spatial memory. Since subliminal noisy galvanic vestibular stimulation (GVS) has been demonstrated to enhance some types of memory, we speculated that application of noisy GVS may improve spatial memory in a rat model of intracerebroventricular streptozotocin (ICV-STZ)-induced cognitive impairment. Moreover, we attempted to determine the effect of repeated exposure to GVS on spatial memory performance. The spatial memory was assessed using Morris water maze test. The groups received 1 (ICV-STZ/GVS-I) or 5 (ICV-STZ/GVS-II) sessions, each lasting 30 min, of low amplitude noisy GVS, or no GVS at all (Control, ICV-saline, ICV-STZ/noGVS). Hippocampal morphological changes investigated with cresyl violet staining and the immediate early gene product c-Fos, as a neuronal activity marker, was measured. Hippocampal c-Fos positive cells increased in both GVS stimulated groups. We observed significantly improved spatial performance only in ICV-STZ/GVS-II group. Histological evaluation showed normal density in ICV-STZ/GVS-II group whereas degeneration observed in ICV-STZ/GVS-I group similar to ICV-STZ/noGVS. The results showed the improvement of memory impairment after repeated exposure to GVS. This effect may be due in part to frequent activation of the vestibular neurons and the hippocampal regions connected to them. Our current study suggests the potential role of GVS as a practical method to combat cognitive decline induced by sporadic Alzheimer disease. PMID:26892259

  5. Prenatal complex rhythmic music sound stimulation facilitates postnatal spatial learning but transiently impairs memory in the domestic chick.

    PubMed

    Kauser, H; Roy, S; Pal, A; Sreenivas, V; Mathur, R; Wadhwa, S; Jain, S

    2011-01-01

    Early experience has a profound influence on brain development, and the modulation of prenatal perceptual learning by external environmental stimuli has been shown in birds, rodents and mammals. In the present study, the effect of prenatal complex rhythmic music sound stimulation on postnatal spatial learning, memory and isolation stress was observed. Auditory stimulation with either music or species-specific sounds or no stimulation (control) was provided to separate sets of fertilized eggs from day 10 of incubation. Following hatching, the chicks at age 24, 72 and 120 h were tested on a T-maze for spatial learning and the memory of the learnt task was assessed 24 h after training. In the posthatch chicks at all ages, the plasma corticosterone levels were estimated following 10 min of isolation. The chicks of all ages in the three groups took less (p < 0.001) time to navigate the maze over the three trials thereby showing an improvement with training. In both sound-stimulated groups, the total time taken to reach the target decreased significantly (p < 0.01) in comparison to the unstimulated control group, indicating the facilitation of spatial learning. However, this decline was more at 24 h than at later posthatch ages. When tested for memory after 24 h of training, only the music-stimulated chicks at posthatch age 24 h took a significantly longer (p < 0.001) time to traverse the maze, suggesting a temporary impairment in their retention of the learnt task. In both sound-stimulated groups at 24 h, the plasma corticosterone levels were significantly decreased (p < 0.001) and increased thereafter at 72 h (p < 0.001) and 120 h which may contribute to the differential response in spatial learning. Thus, prenatal auditory stimulation with either species-specific or complex rhythmic music sounds facilitates spatial learning, though the music stimulation transiently impairs postnatal memory. PMID:21212638

  6. Use of UAS Remote Sensing Data (AggieAir) to Estimate Crop ET at High Spatial Resolution

    NASA Astrophysics Data System (ADS)

    ELarab, M.; Torres, A.; Nieto Solana, H.; Kustas, W. P.; Song, L.; Alfieri, J. G.; Prueger, J. H.; McKee, L.; Anderson, M. C.; Jensen, A.; McKee, M.; Alsina, M. M.

    2015-12-01

    Estimation of the spatial distribution of evapotranspiration (ET) based on remotely sensed imagery has become useful for managing water in irrigated agricultural at various spatial scales. Currently, data acquired by conventional satellites (Landsat, ASTER, etc.) lack the needed spatial resolution to capture variability of interest to support evapotranspiration estimates. In this study, an unmanned aerial system (UAS), called AggieAirTM, was used to acquire high-resolution imagery in the visual, near infrared (0.15m resolution) and thermal infrared spectra (0.6m resolution). AggieAir flew over two study sites in Utah and Central Valley of California. The imagery was used as input to a surface energy balance model based on the Mapping Evapotranspiration with Internalized Calibration (METRIC) modeling approach. The discussion will highlight the ET estimation methodologies and the implications of having high resolution ET maps.

  7. Short-term sleep deprivation impairs spatial working memory and modulates expression levels of ionotropic glutamate receptor subunits in hippocampus.

    PubMed

    Xie, Meilan; Yan, Jie; He, Chao; Yang, Li; Tan, Gang; Li, Chao; Hu, Zhian; Wang, Jiali

    2015-06-01

    Hippocampus-dependent learning memory is sensitive to sleep deprivation (SD). Although the ionotropic glutamate receptors play a vital role in synaptic plasticity and learning and memory, however, whether the expression of these receptor subunits is modulated by sleep loss remains unclear. In the present study, western blotting was performed by probing with specific antibodies against the ionotropic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunits GluA1, GluA2, GluA3, and against the N-methyl-d-aspartate (NMDA) glutamate receptor subunits GluN1, GluN2A, GluN2B. In hippocampus, down regulation of surface GluA1 and GluN2A surface expression were observed in both SD groups. However, surface expression level of GluA2, GluA3, GluN1 and GluN2B was significantly up-regulated in 8h-SD rats when compared to the 4h-SD rats. In parallel with the complex changes in AMPA and NMDA receptor subunit expressions, we found the 8h-SD impaired rat spatial working memory in 30-s-delay T-maze task, whereas no impairment of spatial learning was observed in 4h-SD rats. These results indicate that sleep loss alters the relative expression levels of the AMPA and NMDA receptors, thus affects the synaptic strength and capacity for plasticity and partially contributes to spatial memory impairment. PMID:25732956

  8. Spatial scales of optical variability in the coastal ocean: Implications for remote sensing and in situ sampling

    NASA Astrophysics Data System (ADS)

    Moses, Wesley J.; Ackleson, Steven G.; Hair, Johnathan W.; Hostetler, Chris A.; Miller, W. David

    2016-06-01

    Use of ocean color remote sensing to understand the effects of environmental changes and anthropogenic activities on estuarine and coastal waters requires the capability to measure and track optically detectable complex biogeochemical processes. An important remote sensor design consideration is the minimum spatial resolution required to resolve key ocean features of physical and biological significance. The spatial scale of variability in optical properties of coastal waters has been investigated using continuous, along-track measurements collected using instruments deployed from ships, aircraft, and satellites. We defined the average coefficient of variance, CV¯a, within an image pixel as the primary statistical measure of subpixel variability and investigated how CV¯a changes as a function of the Ground Sampling Distance (GSD). In general, dCV¯a/dGSD is positive, indicating that the subpixel variability increases with GSD. The relationship between CV¯a and GSD is generally nonlinear and the greatest rate of change occurs at small spatial scales. Points of distinct transition in the relationship between CV¯a and GSD are evident between 75 and 600 m, varying depending on the location and the optical parameter, and representing the GSD above which most of the spatial variability due to small-scale features is subsumed within a pixel. At GSDs greater than the transition point, most of the small-scale variability occurs at subpixel scales and, therefore, cannot be resolved. On average, the transition GSD is around 200 m. The results have application in both sensor design and in situ sampling strategy in support of coastal remote sensing operations.

  9. The effects of spatially displaced visual feedback on remote manipulator performance

    NASA Technical Reports Server (NTRS)

    Smith, Randy L.; Stuart, Mark A.

    1993-01-01

    The results of this evaluation have important implications for the arrangement of remote manipulation worksites and the design of workstations for telerobot operations. This study clearly illustrates the deleterious effects that can accompany the performance of remote manipulator tasks when viewing conditions are less than optimal. Future evaluations should emphasize telerobot camera locations and the use of image/graphical enhancement techniques in an attempt to lessen the adverse effects of displaced visual feedback. An important finding in this evaluation is the extent to which results from previously performed direct manipulation studies can be generalized to remote manipulation studies. Even though the results obtained were very similar to those of the direct manipulation evaluations, there were differences as well. This evaluation has demonstrated that generalizations to remote manipulation applications based upon the results of direct manipulation studies are quite useful, but they should be made cautiously.

  10. The Effect of Spatial Tasks on Visually Impaired Peoples' Wayfinding Abilities.

    ERIC Educational Resources Information Center

    Blades, Mark; Lippa, Yvonne; Golledge, Reginald G.; Jacobson, R. Daniel; Kitchin, Robert M.

    2002-01-01

    Thirty-eight people with visual impairments learned a 483-meter novel route through a university campus in four groups: verbalization, modeling, pointing, and control. The performance of all four groups improved with greater experience of the route, but the modeling group improved more than the control group. (Contains references.) (Author/CR)

  11. Visuo-Spatial Processing and Executive Functions in Children with Specific Language Impairment

    ERIC Educational Resources Information Center

    Marton, Klara

    2008-01-01

    Background: Individual differences in complex working memory tasks reflect simultaneous processing, executive functions, and attention control. Children with specific language impairment (SLI) show a deficit in verbal working memory tasks that involve simultaneous processing of information. Aims: The purpose of the study was to examine executive…

  12. Design of the driving system for visible near-infrared spatial programmable push-broom remote CCD sensor

    NASA Astrophysics Data System (ADS)

    Xu, Zhipeng; Wei, Jun; Zhou, Qianting; Weng, Dongshan; Li, Jianwei

    2010-11-01

    VNIR multi-spectral image sensor has wide applications in remote sensing and imaging spectroscopy. An image spectrometer of a spatial remote programmable push-broom sensing satellite requires visible near infrared band ranges from 0.4μm to 1.04μm which is one of the most important bands in remote sensing. This paper introduces a method of design the driving system for 1024x1024 VNIR CCD sensor for programmable push-broom remote sensing. The digital driving signal is generated by the FPGA device. There are seven modules in the FPGA program and all the modules are coded by VHDL. The driving system have five mainly functions: drive the sensor as the demand of timing schedule, control the AD convert device to work, get the parameter via RS232 from control platform, process the data input from the AD device, output the processed data to PCI sample card to display in computer end. All the modules above succeed working on FPGA device APA600. This paper also introduced several important keys when designing the driving system including module synchronization, critical path optimization.

  13. Effect of spatial resolution on remote sensing estimation of total evaporation in the uMngeni catchment, South Africa

    NASA Astrophysics Data System (ADS)

    Shoko, Cletah; Clark, David; Mengistu, Michael; Dube, Timothy; Bulcock, Hartley

    2015-01-01

    This study evaluated the effect of two readily available multispectral sensors: the newly launched 30 m spatial resolution Landsat 8 and the long-serving 1000 m moderate resolution imaging spectroradiometer (MODIS) datasets in the spatial representation of total evaporation in the heterogeneous uMngeni catchment, South Africa, using the surface energy balance system model. The results showed that sensor spatial resolution plays a critical role in the accurate estimation of energy fluxes and total evaporation across a heterogeneous catchment. Landsat 8 estimates showed better spatial representation of the biophysical parameters and total evaporation for different land cover types, due to the relatively higher spatial resolution compared to the coarse spatial resolution MODIS sensor. Moreover, MODIS failed to capture the spatial variations of total evaporation estimates across the catchment. Analysis of variance (ANOVA) results showed that MODIS-based total evaporation estimates did not show any significant differences across different land cover types (one-way ANOVA; F1.924=1.412, p=0.186). However, Landsat 8 images yielded significantly different estimates between different land cover types (one-way ANOVA; F1.993=5.185, p<0.001). The validation results showed that Landsat 8 estimates were more comparable to eddy covariance (EC) measurements than the MODIS-based total evaporation estimates. EC measurement on May 23, 2013, was 3.8 mm/day, whereas the Landsat 8 estimate on the same day was 3.6 mm/day, with MODIS showing significantly lower estimates of 2.3 mm/day. The findings of this study underscore the importance of spatial resolution in estimating spatial variations of total evaporation at the catchment scale, thus, they provide critical information on the relevance of the readily available remote sensing products in water resources management in data-scarce environments.

  14. Categorical spatial memory in patients with mild cognitive impairment and Alzheimer dementia: positional versus object-location recall.

    PubMed

    Kessels, Roy P C; Rijken, Stefan; Joosten-Weyn Banningh, Liesbeth W A; Van Schuylenborgh-VAN Es, Nelleke; Olde Rikkert, Marcel G M

    2010-01-01

    Memory for object locations, as part of spatial memory function, has rarely been studied in patients with Alzheimer dementia (AD), while studies in patients with Mild Cognitive Impairment (MCI) patients are lacking altogether. The present study examined categorical spatial memory function using the Location Learning Test (LLT) in MCI patients (n = 30), AD patients (n = 30), and healthy controls (n = 40). Two scoring methods were compared, aimed at disentangling positional recall (location irrespective of object identity) and object-location binding. The results showed that AD patients performed worse than the MCI patients on the LLT, both on recall of positional information and on recall of the locations of different objects. In addition, both measures could validly discriminate between AD and MCI patients. These findings are in agreement with the notion that visual cued-recall tests may have better diagnostic value than traditional (verbal) free-recall tests in the assessment of patients with suspected MCI or AD. PMID:19883520

  15. Adolescent exposure to Bisphenol-A increases anxiety and sucrose preference but impairs spatial memory in rats independent of sex.

    PubMed

    Diaz Weinstein, Samantha; Villafane, Joseph J; Juliano, Nicole; Bowman, Rachel E

    2013-09-01

    The endocrine disruptor Bisphenol-A (BPA) has been shown to modulate estrogenic, androgenic, and anti-androgenic effects. The effects of BPA exposure during early organizational periods of development have been well documented. The current study focuses on the effects of short term, low-dose BPA exposure on anxiety, spatial memory and sucrose preference in adolescent rats. Seven week old Sprague Dawley rats (n=18 male, n=18 female) received daily subcutaneous injections (40 µg/kg body weight) of BPA or vehicle for 12 days. Starting on day 6 of injections, subjects were tested on the elevated plus maze which provides a measure of anxiety, the open field test which provides a measure of anxiety and locomotor activity, and object placement, a measure of spatial memory. On the twelfth day of BPA administration, sucrose preference was tested using a standard two-bottle choice (tap versus sucrose solution). All rats gained weight during the study; there was a main effect of sex, but not BPA treatment on body weight. The results indicate that BPA exposure, regardless of sex, increased anxiety on both the elevated plus maze and open field. Spatial memory was impaired on the object recognition task with BPA animals spending significant less time with the object in the novel location than controls. Finally, a significant increase in sucrose consumption for both male and female subjects exposed to BPA was observed. The current data shows that short term BPA exposure, below the current reference safe daily limit of 50 µg/kg day set by the United States Environmental Protection Agency, during adolescent development increases anxiety, impairs spatial memory, and increases sucrose consumption independent of sex. PMID:23872220

  16. Does Knowledge of Spatial Configuration in Adults with Visual Impairments Improve with Tactile Exposure to a Small-Scale Model of Their Urban Environment?

    ERIC Educational Resources Information Center

    Picard, Delphine; Pry, Rene

    2009-01-01

    This study assessed the efficiency of a model of a familiar urban area for enhancing knowledge of the spatial environment by adults with visual impairments. It found a significant improvement in knowledge of spatial configuration after exposure to the model, suggesting that models are powerful means of developing cognitive mapping in people who…

  17. [The Change Detection of High Spatial Resolution Remotely Sensed Imagery Based on OB-HMAD Algorithm and Spectral Features].

    PubMed

    Chen, Qiang; Chen, Yun-hao; Jiang, Wei-guo

    2015-06-01

    The high spatial resolution remotely sensed imagery has abundant detailed information of earth surface, and the multi-temporal change detection for the high resolution remotely sensed imagery can realize the variations of geographical unit. In terms of the high spatial resolution remotely sensed imagery, the traditional remote sensing change detection algorithms have obvious defects. In this paper, learning from the object-based image analysis idea, we proposed a semi-automatic threshold selection algorithm named OB-HMAD (object-based-hybrid-MAD), on the basis of object-based image analysis and multivariate alternative detection algorithm (MAD), which used the spectral features of remotely sensed imagery into the field of object-based change detection. Additionally, OB-HMAD algorithm has been compared with other the threshold segmentation algorithms by the change detection experiment. Firstly, we obtained the image object by the multi-solution segmentation algorithm. Secondly, we got the object-based difference image object using MAD and minimum noise fraction rotation (MNF) for improving the SNR of the image object. Then, the change objects or area are classified using histogram curvature analysis (HCA) method for the semi-automatic threshold selection, which determined the threshold by calculated the maximum value of curvature of the histogram, so the HCA algorithm has better automation than other threshold segmentation algorithms. Finally, the change detection results are validated using confusion matrix with the field sample data. Worldview-2 imagery of 2012 and 2013 in case study of Beijing were used to validate the proposed OB-HMAD algorithm. The experiment results indicated that OB-HMAD algorithm which integrated the multi-channel spectral information could be effectively used in multi-temporal high resolution remotely sensed imagery change detection, and it has basically solved the "salt and pepper" problem which always exists in the pixel-based change

  18. Methamphetamine exposure from postnatal day 11 to 20 causes impairments in both behavioral strategies and spatial learning in adult rats.

    PubMed

    Williams, Michael T; Vorhees, Charles V; Boon, Francis; Saber, Andrea J; Cain, Donald P

    2002-12-27

    Spatial learning and memory deficits in a water maze have been observed in adult animals exposed to a regimen of 4 daily doses of d-methamphetamine (MA) at 2 h intervals from postnatal day 11 to 20. An interpretational issue for these long-term effects of MA is whether they are truly spatial deficits or are secondary to alterations in sensorimotor systems. In this experiment, we evaluated the effects of a pretraining procedure shown to minimize the influence of drug-induced sensorimotor deficits. Animals within a litter were treated with MA or saline. Animals were either pretrained for nonspatial task requirements in the water maze (i.e., swimming and platform climbing) or were nai;ve to the task. Animals that received the pretraining did better than the nai;ve animals. The nai;ve MA animals performed worse than the nai;ve control animals as previously observed. By contrast, no difference in search time was noted between pretrained MA- and SAL-treated animals during the acquisition phase of testing. When the platform was relocated in a novel position, spatial learning was impaired for MA animals, regardless of pretraining. No increase in the number of platform nonrecognition events (swimovers, deflections, or jump-offs) occurred among pretrained or nai;ve groups compared to controls. These data suggest that sensorimotor deficits do not account for the spatial learning and memory deficits in animals exposed neonatally to MA. PMID:12470867

  19. MDMA pretreatment leads to mild chronic unpredictable stress-induced impairments in spatial learning.

    PubMed

    Cunningham, Jacobi I; Raudensky, Jamie; Tonkiss, John; Yamamoto, Bryan K

    2009-10-01

    3,4-Methylenedioxymethamphetamine (MDMA) is a drug of abuse worldwide and a selective serotonin (5-HT) neurotoxin. An important factor in the risk of drug abuse and relapse is stress. Although multiple parallels exist between MDMA abuse and stress, including effects on 5-HTergic neurotransmission, few studies have investigated the consequences of combined exposure to MDMA and chronic stress. Therefore, rats were pretreated with MDMA and exposed 7 days later to 10 days of mild chronic unpredictable stress (CUS). MDMA pretreatment was hypothesized to enhance the effects of CUS leading to enhanced 5-HT transporter (SERT) depletion in the hippocampus and increased anxiety and cognitive impairment. Whereas MDMA alone increased anxiety-like behavior on the elevated plus maze, CUS alone or in combination with MDMA pretreatment did not increase anxiety-like behavior. In contrast, MDMA pretreatment led to CUS-induced learning impairment in the Morris water maze but not an enhanced depletion of hippocampal SERT protein. These results show that prior exposure to MDMA leads to stress-induced impairments in learning behavior that is not otherwise observed with stress alone and appear unrelated to an enhanced depletion of SERT. PMID:19824774

  20. Saffron ethanolic extract attenuates oxidative stress, spatial learning, and memory impairments induced by local injection of ethidium bromide

    PubMed Central

    Ghaffari, Sh.; Hatami, H.; Dehghan, Gh.

    2015-01-01

    Cognitive deficits have been observed in patients with multiple sclerosis (MS) because of hippocampal insults. Oxidative stress plays a key role in the pathophysiology of MS. The aim of this study was to evaluate the effects of Crocus sativus L., commonly known as saffron, on learning and memory loss and the induction of oxidative stress in the hippocampus of toxic models of MS. One week after MS induction by intrahippocampal injection of ethidium bromide (EB), animals were treated with two doses of saffron extract (5 and 10 μg/rat) for a week. Learning and spatial memory status was assessed using Morris Water Maze. After termination of behavioral testing days, animals were decapitated and the bilateral hippocampi dissected to measure some of the oxidative stress markers including the level of hippocampi thiobarbituric acid reactive substances and the activity of antioxidant enzymes such as glutathione peroxidase and superoxide dismutase. Treatment with saffron extract ameliorated spatial learning and memory impairment (P<0.05). Total antioxidant reactivity capacity, lipid peroxidation products and antioxidant enzymes activity in the hippocampus homogenates of EB treated group were significantly higher than those of all other groups (P<0.01). Indeed, treatment with a saffron extract for 7 consecutive days significantly restored the antioxidant status to the normal levels (P<0.01). These observations reveal that saffron extract can ameliorate the impairment of learning and memory as well as the disturbances in oxidative stress parameters in the hippocampus of experimental models of MS. PMID:26600849

  1. Cerebral ischemia combined with beta-amyloid impairs spatial memory in the eight-arm radial maze task in rats.

    PubMed

    Iwasaki, Katsunori; Egashira, Nobuaki; Hatip-Al-Khatib, Izzettin; Akiyoshi, Yuki; Arai, Takashi; Takagaki, Yuki; Watanabe, Takuya; Mishima, Kenichi; Fujiwara, Michihiro

    2006-06-30

    beta-Amyloid (Abeta), a major component of senile plaques in Alzheimer's disease, has been implicated in neuronal cell death, a characteristic feature of this condition. In our previous experiments using primary cultures of hippocampal neurons, Abeta treatment induced neuronal cell death, displaying morphological characteristics of apoptosis that was significantly enhanced by hypoxia. Based on these results, we developed a simple in vivo rat model of Alzheimer's disease using cerebral ischemia, instead of hypoxia, combined with continuous intracerebroventricular administration of Abeta. The combination of cerebral ischemia and Abeta administration, but not either treatment alone, significantly impaired spatial memory in an eight-arm radial maze. A microdialysis study showed that spontaneous release of acetylcholine (ACh) from the dorsal hippocampus had a tendency to decrease in response to Abeta treatment alone or the combination of ischemia and Abeta. High K(+)-evoked increase in ACh release had a tendency to be inhibited by either ischemia or Abeta treatment alone and was significantly inhibited by the combination of both. Moreover, combination of ischemia and Abeta induced apoptosis of pyramidal neurons in the CA1 region of the hippocampus. Donepezil, a drug currently in clinical use for Alzheimer's disease, improved the impairment of spatial memory induced by cerebral ischemia combined with Abeta. These findings suggest that ischemia is an important factor facilitating the symptoms of Alzheimer's disease, and this model may be useful for developing new drugs for the treatment of Alzheimer's disease. PMID:16729978

  2. Chronic treatment with a GPR30 antagonist impairs acquisition of a spatial learning task in young female rats

    PubMed Central

    Hammond, R.; Nelson, D.; Kline, E.; Gibbs, RB

    2012-01-01

    We hypothesize that the beneficial effects estradiol on cognitive performance may be mediated through GPR30, a putative membrane target of estrogens. Recently we showed that administration of a selective GPR30 agonist (G-1) to ovariectomized rats enhanced acquisition of a delayed matching-to-position (DMP) T-maze task and increased potassium-stimulated acetylcholine release in the hippocampus, similar to estradiol (E2) (Hammond et al., 2009). The present study tested whether treating with a selective GPR30 antagonist (G-15) would impair spatial learning in gonadally intact rats and in ovariectomized (OVX) rats treated with E2. As predicted, G-15 dose-dependently impaired DMP acquisition both in gonadally intact rats and in OVX rats treated with E2. G-15 specifically reduced the rate of acquisition, and this effect was associated with an increased predisposition to adopt a persistent turn. In contrast, G-15 alone at the highest dose had no significant effect on DMP acquisition in OVX controls. The effects were task dependent, as similar effects of G-15 were not observed in gonadally intact rats tested on an operant discrimination/reversal learning task motivated by the same food reward. This suggests that the effects on DMP acquisition were not due to effects on motivation for food. Effects of G-15 on DMP acquisition were similar to previously published work showing significant impairment produced by selective cholinergic denervation of the hippocampus. These data suggest that GPR30 can play an important role in mediating the effects of estradiol on spatial learning, possibly by mediating estradiol effects on basal forebrain cholinergic function. PMID:22828404

  3. Evidence for synchronicity of lightning activity in networks of spatially remote thunderstorms

    NASA Astrophysics Data System (ADS)

    Yair, Yoav; Aviv, Reuven; Ravid, Gilad; Yaniv, Roy; Ziv, Baruch; Price, Colin

    2006-08-01

    Visual observations by space shuttle astronauts have described a phenomenon in which spatially distant thunderstorm cells seem to reciprocally “ignite” lightning flashes in a semi-cyclic sequence. Lightning occurring in one cell is immediately followed by lightning in other cells, separated by tens or hundreds of kilometers. We present quantitative analysis of lightning observations conducted within the framework of the MEIDEX-sprite campaign on board the space shuttle Columbia in January 2003 [Yair, Y., Israelevich, P., Devir, A., Moalem, M., Price, C., Joseph, J., Levin, Z., Ziv, B., Teller, A., 2004. New sprites observations from the space shuttle. Journal of Geophysical Research 109, D15201/10.1029/2003JD004497]. Video footage of 6 storm systems with varying flash rates, which occurred over Africa, South America, Australia and the Pacific Ocean were analyzed. It is found that when the storm flash rate was high, lightning activity in horizontally remote electrically active cells became clustered, with bursts of nearly simultaneous activity separated by quiet periods. The recurrence time was ˜2.5 s, close to the previously reported time delay between consecutive ELF transient signals in the Schumann resonance range [Füllekrug, M., 1995. Schumann resonances in magnetic filed components. Journal of Atmospheric and Terresterial Physics 57, 479 484]. We propose that this behavior is similar to the collective dynamics of a network of weakly coupled limit-cycle oscillators [Strogatz, S.H., 2000, From Kuramoto to Crawford: exploring the onset of synchronization in populations of coupled oscillators. Physica, D, 1 20]. Thunderstorm cells embedded within a mesoscale convective system (MCS) constitute such a network, and their lightning frequency is best described in terms of phase-locking of a globally coupled array [Kourtchatov, S.Y., Yu, V.V., Likhanskii, V.V., Napartovitch, A.P., Arecchi, F.T., Lapucci, A., 1995 Theory of phase locking of globally coupled laser

  4. Exposure to low doses (20 cGy) of Hze results in spatial memory impairment in rats.

    NASA Astrophysics Data System (ADS)

    Britten, Richard; Johnson, Angela; Davis, Leslie; Green-Mitchell, Shamina; Chabriol, Olivia; Sanford, Larry; Drake, Richard

    INTRODUCTION. Current models predict that the astronauts on a mission to a deep space destination, such as Mars, will be exposed to 25 cGy of Galactic cosmic radiation (GCR). The long-term consequence of exposure to such doses is largely unknown, but given that 1.3 Gy of X-rays has been reported to lead to long-term cognitive deficits (Shore et al, 1976) and that CGR have an RBE of 2-5, it is likely that the predicted 25 cGy of GCR will lead to defects in the cognitive ability of the astronauts during and after the mission. Our studies are designed to help define the GCR dose that will lead to defects in complex working memory, and also to elucidate the mechanisms whereby hadronic radiation diminishes neurocognitive function. The identification of such processes would provide an opportunity for post-mission surveillance, and hopefully will lead to intervention strategies that will ameliorate or attenuate GCR-induced neurocognitive deficits. MATERIALS METHODS. Four-week old male Wistar rats were exposed to either X-rays or 1 GeV 56Fe. At three or six months post exposure the performance of the rats in the Barnes' Maze (Spatial memory) was established. The duration and frequency of REM sleep was also monitored to determine if the neurocognitive deficits arose due to reduced memory consolidation as a result of diminished REM sleep. We used a novel, but maturing technique, called MALDI-MS imaging (or MALDI-MSI), to identify specific regions of the brain where the neuroproteome differs in rats that have developed spatial memory impairments. RESULTS. 11.5 Gy of X-rays led to reduced performance in the Barnes's maze. In contrast, exposure to 20 cGy of Hze (1 GeV 56Fe) resulted in a significant impairment of spatial memory performance as measured in the Barnes' Maze, which was manifested by an increase in relative escape latency REL over a 5 day testing period. Such an increase in REL could arise from the rats becoming less able, or perhaps less willing, to locate the

  5. Detecting spatial and temporal patterns of aboveground production in a tallgrass prairie using remotely sensed data

    SciTech Connect

    Su, Haiping; Krummel, J.R.; Briggs, J.M.; Knapp, A.K.; Blair, J.M.

    1996-05-01

    Spatial and temporal patterns of aboveground production is a tallgrass prairie ecosystem constitute one of the important spatial components associated with ecological processes and biophysical resources (e.g. water and nutrients). This study addresses the effects of disturbance, topography, and climate on the spatial and temporal patterns of North American tallgrass prairie at a landscape level by using high resolution satellite data. Spatial heterogeneity derived from the satellite data was related to the impacts of the disturbance of fire and grazing, topographical gradient, and amount of precipitation during the growing season. The result suggests that ecological processes and biophysical resources can be quantified with high resolution satellite data for tallgrass prairie management.

  6. Repeated neonatal propofol administration induces sex-dependent long-term impairments on spatial and recognition memory in rats.

    PubMed

    Gonzales, Edson Luck T; Yang, Sung Min; Choi, Chang Soon; Mabunga, Darine Froy N; Kim, Hee Jin; Cheong, Jae Hoon; Ryu, Jong Hoon; Koo, Bon-Nyeo; Shin, Chan Young

    2015-05-01

    Propofol is an anesthetic agent that gained wide use because of its fast induction of anesthesia and rapid recovery post-anesthesia. However, previous studies have reported immediate neurodegeneration and long-term impairment in spatial learning and memory from repeated neonatal propofol administration in animals. Yet, none of those studies has explored the sex-specific long-term physical changes and behavioral alterations such as social (sociability and social preference), emotional (anxiety), and other cognitive functions (spatial working, recognition, and avoidance memory) after neonatal propofol treatment. Seven-day-old Wistar-Kyoto (WKY) rats underwent repeated daily intraperitoneal injections of propofol or normal saline for 7 days. Starting fourth week of age and onwards, rats were subjected to behavior tests including open-field, elevated-plus-maze, Y-maze, 3-chamber social interaction, novel-object-recognition, passive-avoidance, and rotarod. Rats were sacrificed at 9 weeks and hippocampal protein expressions were analyzed by Western blot. Results revealed long-term body weight gain alterations in the growing rats and sex-specific impairments in spatial (female) and recognition (male) learning and memory paradigms. A markedly decreased expression of hippocampal NMDA receptor GluN1 subunit in female- and increased expression of AMPA GluR1 subunit protein expression in male rats were also found. Other aspects of behaviors such as locomotor activity and coordination, anxiety, sociability, social preference and avoidance learning and memory were not generally affected. These results suggest that neonatal repeated propofol administration disrupts normal growth and some aspects of neurodevelopment in rats in a sex-specific manner. PMID:25995824

  7. Repeated Neonatal Propofol Administration Induces Sex-Dependent Long-Term Impairments on Spatial and Recognition Memory in Rats

    PubMed Central

    Gonzales, Edson Luck T.; Yang, Sung Min; Choi, Chang Soon; Mabunga, Darine Froy N.; Kim, Hee Jin; Cheong, Jae Hoon; Ryu, Jong Hoon; Koo, Bon-Nyeo; Shin, Chan Young

    2015-01-01

    Propofol is an anesthetic agent that gained wide use because of its fast induction of anesthesia and rapid recovery post-anesthesia. However, previous studies have reported immediate neurodegeneration and long-term impairment in spatial learning and memory from repeated neonatal propofol administration in animals. Yet, none of those studies has explored the sex-specific long-term physical changes and behavioral alterations such as social (sociability and social preference), emotional (anxiety), and other cognitive functions (spatial working, recognition, and avoidance memory) after neonatal propofol treatment. Seven-day-old Wistar-Kyoto (WKY) rats underwent repeated daily intraperitoneal injections of propofol or normal saline for 7 days. Starting fourth week of age and onwards, rats were subjected to behavior tests including open-field, elevated-plus-maze, Y-maze, 3-chamber social interaction, novel-object-recognition, passive-avoidance, and rotarod. Rats were sacrificed at 9 weeks and hippocampal protein expressions were analyzed by Western blot. Results revealed long-term body weight gain alterations in the growing rats and sex-specific impairments in spatial (female) and recognition (male) learning and memory paradigms. A markedly decreased expression of hippocampal NMDA receptor GluN1 subunit in female- and increased expression of AMPA GluR1 subunit protein expression in male rats were also found. Other aspects of behaviors such as locomotor activity and coordination, anxiety, sociability, social preference and avoidance learning and memory were not generally affected. These results suggest that neonatal repeated propofol administration disrupts normal growth and some aspects of neurodevelopment in rats in a sex-specific manner. PMID:25995824

  8. Temporal and spatial variability of aerosol optical depth in the Sahel region in relation to vegetation remote sensing

    NASA Technical Reports Server (NTRS)

    Holben, B. N.; Fraser, R. S.; Eck, T. F.

    1991-01-01

    In order to monitor the aerosol characteristics needed for atmospheric correction of remotely sensed data, a network of sun photometers was established in the Sahel region of Senegal, Mali, and Niger. Data analysis suggests that there is a high spatial variability of the aerosol optical thickness tau(a) in the western Sahel region. At a 67 percent confidence level the instantaneous values of tau(a) can be extrapolated approximately 270-400 km with an error tolerance of 50 percent. Spatial variability in the dry season is found to be of a similar magnitude. The ranges of variations in the NDVI in the Sahel region are shown to be approximately 0.02 and 0.01, respectively, due to commonly observed fluctuations in the aerosol optical thickness and aerosol size distribution.

  9. Method and apparatus for spatially variable rate application of agricultural chemicals based on remotely sensed vegetation data

    NASA Technical Reports Server (NTRS)

    Hood, Kenneth Brown (Inventor); Seal, Michael R. (Inventor); Lewis, Mark David (Inventor); Johnson, James William (Inventor)

    2004-01-01

    Remotely sensed spectral image data are used to develop a Vegetation Index file which represents spatial variations of actual crop vigor throughout a field that is under cultivation. The latter information is processed to place it in a format that can be used by farm personnel to correlate and calibrate it with actually observed crop conditions existing at control points within the field. Based on the results, farm personnel formulate a prescription request, which is forwarded via email or FTP to a central processing site, where the prescription is prepared. The latter is returned via email or FTP to on-side farm personnel, who can load it into a controller on a spray rig that directly applies inputs to the field at a spatially variable rate.

  10. Method and system for spatially variable rate application of agricultural chemicals based on remotely sensed vegetation data

    NASA Technical Reports Server (NTRS)

    Hood, Kenneth Brown (Inventor); Seal, Michael R. (Inventor); Lewis, Mark David (Inventor); Johnson, James William (Inventor)

    2007-01-01

    Remotely sensed spectral image data are used to develop a Vegetation Index file which represents spatial variations of actual crop vigor throughout a field that is under cultivation. The latter information is processed to place it in a format that can be used by farm personnel to correlate and calibrate it with actually observed crop conditions existing at control points within the field. Based on the results, farm personnel formulate a prescription request, which is forwarded via email or FTP to a central processing site, where the prescription is prepared. The latter is returned via email or FTP to on-side farm personnel, who can load it into a controller on a spray rig that directly applies inputs to the field at a spatially variable rate.

  11. Correcting for Atmospheric Spatial Variability When Estimating Surface Fluxes from Remotely Sensed Land Surface Data

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Efforts to monitor the terrestrial water cycle require accurate estimates of evapotranspiration over the global land area. Flux towers provide valuable site-level data, but their collective footprints cover only a very small fraction of the land surface. Satellite remote sensing instruments, on th...

  12. Remote Control: A Spatial-History of Correspondence Schooling in New South Wales, Australia

    ERIC Educational Resources Information Center

    Symes, Colin

    2012-01-01

    In large continental landmasses such as Australia, forms of education, including correspondence schooling, emerged in the early twentieth century that allowed children in remote regions to access education. To make such schooling possible, other "technologies" of state provision were mobilised such as the postal system, rail network, and radio…

  13. Monitoring of vegetation impact due to trampling on Cadillac Mountain summit using high spatial resolution remote sensing data sets.

    PubMed

    Kim, Min-Kook; Daigle, John J

    2012-11-01

    Cadillac Mountain--the highest peak along the eastern seaboard of the United States--is a major tourist destination in Acadia National Park, Maine. Managing vegetation impact due to trampling on the Cadillac Mountain summit is extremely challenging because of the large number of visitors and the general open nature of landscape in this fragile subalpine environmental setting. Since 2000, more intensive management strategies--based on placing physical barriers and educational messages for visitors--have been employed to protect threatened vegetation, decrease vegetation impact, and enhance vegetation recovery in the vicinity of the summit loop trail. The primary purpose of this study was to evaluate the effect of the management strategies employed. For this purpose, vegetation cover changes between 2001 and 2007 were detected using multispectral high spatial resolution remote sensing data sets. A normalized difference vegetation index was employed to identify the rates of increase and decrease in the vegetation areas. Three buffering distances (30, 60, and 90 m) from the edges of the trail were used to define multiple spatial extents of the site, and the same spatial extents were employed at a nearby control site that had no visitors. No significant differences were detected between the mean rates of vegetation increase and decrease at the experimental site compared with a nearby control site in the case of a small spatial scale (≤30 m) comparison (in all cases P > 0.05). However, in the medium (≤60 m) and large (≤90 m) spatial scales, the rates of increased vegetation were significantly greater and rates of decreased vegetation significantly lower at the experimental site compared with the control site (in all cases P < 0.001). Research implications are explored that relate to the spatial extent of the radial patterns of impact of trampling on vegetation at the site level. Management implications are explored in terms of the spatial strategies used to

  14. Monitoring of Vegetation Impact Due to Trampling on Cadillac Mountain Summit Using High Spatial Resolution Remote Sensing Data Sets

    NASA Astrophysics Data System (ADS)

    Kim, Min-Kook; Daigle, John J.

    2012-11-01

    Cadillac Mountain—the highest peak along the eastern seaboard of the United States—is a major tourist destination in Acadia National Park, Maine. Managing vegetation impact due to trampling on the Cadillac Mountain summit is extremely challenging because of the large number of visitors and the general open nature of landscape in this fragile subalpine environmental setting. Since 2000, more intensive management strategies—based on placing physical barriers and educational messages for visitors—have been employed to protect threatened vegetation, decrease vegetation impact, and enhance vegetation recovery in the vicinity of the summit loop trail. The primary purpose of this study was to evaluate the effect of the management strategies employed. For this purpose, vegetation cover changes between 2001 and 2007 were detected using multispectral high spatial resolution remote sensing data sets. A normalized difference vegetation index was employed to identify the rates of increase and decrease in the vegetation areas. Three buffering distances (30, 60, and 90 m) from the edges of the trail were used to define multiple spatial extents of the site, and the same spatial extents were employed at a nearby control site that had no visitors. No significant differences were detected between the mean rates of vegetation increase and decrease at the experimental site compared with a nearby control site in the case of a small spatial scale (≤30 m) comparison (in all cases P > 0.05). However, in the medium (≤60 m) and large (≤90 m) spatial scales, the rates of increased vegetation were significantly greater and rates of decreased vegetation significantly lower at the experimental site compared with the control site (in all cases P < 0.001). Research implications are explored that relate to the spatial extent of the radial patterns of impact of trampling on vegetation at the site level. Management implications are explored in terms of the spatial strategies used to

  15. Autonomous agricultural remote sensing systems with high spatial and temporal resolutions

    NASA Astrophysics Data System (ADS)

    Xiang, Haitao

    In this research, two novel agricultural remote sensing (RS) systems, a Stand-alone Infield Crop Monitor RS System (SICMRS) and an autonomous Unmanned Aerial Vehicles (UAV) based RS system have been studied. A high-resolution digital color and multi-spectral camera was used as the image sensor for the SICMRS system. An artificially intelligent (AI) controller based on artificial neural network (ANN) and an adaptive neuro-fuzzy inference system (ANFIS) was developed. Morrow Plots corn field RS images in the 2004 and 2006 growing seasons were collected by the SICMRS system. The field site contained 8 subplots (9.14 m x 9.14 m) that were planted with corn and three different fertilizer treatments were used among those subplots. The raw RS images were geometrically corrected, resampled to 10cm resolution, removed soil background and calibrated to real reflectance. The RS images from two growing seasons were studied and 10 different vegetation indices were derived from each day's image. The result from the image processing demonstrated that the vegetation indices have temporal effects. To achieve high quality RS data, one has to utilize the right indices and capture the images at the right time in the growing season. Maximum variations among the image data set are within the V6-V10 stages, which indicated that these stages are the best period to identify the spatial variability caused by the nutrient stress in the corn field. The derived vegetation indices were also used to build yield prediction models via the linear regression method. At that point, all of the yield prediction models were evaluated by comparing the R2-value and the best index model from each day's image was picked based on the highest R 2-value. It was shown that the green normalized difference vegetation (GNDVI) based model is more sensitive to yield prediction than other indices-based models. During the VT-R4 stages, the GNDVI based models were able to explain more than 95% potential corn yield

  16. Using a Sonified Topographic Approach to Communicate Spatial Information to People with Visual Impairments

    ERIC Educational Resources Information Center

    Thebpanya, Paporn

    2010-01-01

    This study implemented tactile interfaces with audio representations to convey spatial information on topographic maps. Two sound variables, pitch and duration, were incorporated with contour lines to represent various aspects of topographic features such as elevation, slope, profile, and landform. The effect of one sound variable (pitch) vs. a…

  17. Using remote sensing and spatial analysis of trees characteristics for long-term monitoring in arid environments

    NASA Astrophysics Data System (ADS)

    Isaacson, Sivan; Blumberg, Dan G.; Rachmilevitch, Shimon; Ephrath, Jhonathan E.; Maman, Shimrit

    2016-04-01

    Trees play a significant role in the desert ecosystem by moderating the extreme environmental conditions including radiation, temperature, low humidity and small amount of precipitation. Trees In arid environments such an Acacia are considered to be `keystone species', because they have major influence over both plants and animal species. Long term monitoring of acacia tree population in those areas is thus essential tool to estimate the overall ecosystem condition. We suggest a new remote sensing data analysis technique that can be integrated with field long term monitoring of trees in arid environments and improve our understanding of the spatial and temporal changes of these populations. In this work we have studied the contribution of remote sensing methods to long term monitoring of acacia trees in hyper arid environments. In order to expand the time scope of the acacia population field survey, we implemented two different approaches: (1) Trees individual based change detection using Corona satellite images and (2) Spatial analysis of trees population, converting spatial data into temporal data. A map of individual acacia trees that was extracted from a color infra-red (CIR) aerial photographs taken at 2010 allowed us to examine the distribution pattern of the trees size and foliage health status (NDVI). Comparison of the tree sizes distribution and NDVI values distribution enabled us to differentiate between long-term (decades) and short-term (months to few years) processes that brought the population to its present state. The spatial analysis revealed that both tree size and NDVI distribution patterns were significantly clustered, suggesting that the processes responsible for tree size and tree health status (i.e., flash-floods spatial spreading) have a spatial expression. The distribution of the trees in the Wadi (ephemeral river) was divided into three distinct parts: large trees with high NDVI values, large trees with low NDVI values and small trees with

  18. Zaprinast impairs spatial memory by increasing PDE5 expression in the rat hippocampus.

    PubMed

    Giorgi, Mauro; Pompili, Assunta; Cardarelli, Silvia; Castelli, Valentina; Biagioni, Stefano; Sancesario, Giuseppe; Gasbarri, Antonella

    2015-02-01

    In this work, we report the effect of post-training intraperitoneal administration of zaprinast on rat memory retention in the Morris water maze task that revealed a significant memory impairment at the intermediate dose of 10mg/kg. Zaprinast is capable of inhibiting both striatal and hippocampal PDE activity but to a different extent which is probably due to the different PDE isoforms expressed in these areas. To assess the possible involvement of cyclic nucleotides in rat memory impairment, we compared the effects obtained 30 min after the zaprinast injection with respect to 24h after injection by measuring both cyclic nucleotide levels and PDE activity. As expected, 30 min after the zaprinast administration, we observed an increase of cyclic nucleotides, which returned to a basal level within 24h, with the exception of the hippocampal cGMP which was significantly decreased at the dose of 10mg/kg of zaprinast. This increase in the hippocampal region is the result of a cGMP-specific PDE5 induction, confirmed by sildenafil inhibition, in agreement with literature data that demonstrate transcriptional regulation of PDE5 by cAMP/cGMP intracellular levels. Our results highlight the possible rebound effect of PDE inhibitors. PMID:25281278

  19. Remote sensing for precision agriculture: Within-field spatial variability analysis and mapping with aerial digital multispectral images

    NASA Astrophysics Data System (ADS)

    Gopalapillai, Sreekala

    2000-10-01

    Advances in remote sensing technology and biological sensors provided the motivation for this study on the applications of aerial multispectral remote sensing in precision agriculture. The feasibility of using high-resolution multispectral remote sensing for precision farming applications such as soil type delineation, identification of crop nitrogen levels, and modeling and mapping of weed density distribution and yield potential within a crop field was explored in this study. Some of the issues such as image calibration for variable lighting conditions and soil background influence were also addressed. Intensity normalization and band ratio methods were found to be adequate image calibration methods to compensate for variable illumination and soil background influence. Several within-field variability factors such as growth stage, field conditions, nutrient availability, crop cultivar, and plant population were found to be dominant in different periods. Unsupervised clustering of color infrared (CIR) image of a field soil was able to identify soil mapping units with an average accuracy of 76%. Spectral reflectance from a crop field was highly correlated to the chlorophyll reading. A regression model developed to predict nitrogen stress in corn identified nitrogen-stressed areas from nitrogen-sufficient areas with a high accuracy (R2 = 0.93). Weed density was highly correlated to the spectral reflectance from a field. One month after planting was found to be a good time to map spatial weed density. The optimum range of resolution for weed mapping was 4 m to 4.5 m for the remote sensing system and the experimental field used in this study. Analysis of spatial yield with respect to spectral reflectance showed that the visible and NIR reflectance were negatively correlated to yield and crop population in heavily weed-infested areas. The yield potential was highly correlated to image indices, especially to normalized brightness. The ANN model developed for one of the

  20. Impaired spatial working memory and decreased frontal cortex BDNF protein level in dopamine transporter knock out mice

    PubMed Central

    Li, BingJin; Arime, Yosefu; Hall, F. Scott; Uhl, George R.; Sora, Ichiro

    2010-01-01

    Brain-derived neurotrophic factor (BDNF), one of the key brain neurotrophins, has been implicated in neuronal plasticity and memory. Recent studies document the importance of BDNF for normal long-term memory functions. However, there are few studies of the roles of BDNF in short term memory. Dopamine is likely to play important roles in BDNF gene expression in specific brain regions, including frontal cortical regions that are implicated in short term working memory processes that include spontaneous alternation. We have thus tested spatial working memory in dopamine transporter knockout (DAT KO) and wild-type mice. Spontaneous alternation in the Y-maze, an index of short-term spatial working memory in mice, was significantly decreased in DAT KO mice compared to wildtype mice. BDNF protein was significantly decreased in frontal cortex, though not in striatum or hippocampus, of the DAT KO mice. The data support the hypothesis that impaired spatial working memory in DAT KO mice may be related to decreased frontal cortical BDNF in these animals, and document apparent roles for BDNF in a short term memory process. PMID:19932884

  1. N-Acetylcysteine Prevents Spatial Memory Impairment Induced by Chronic Early Postnatal Glutaric Acid and Lipopolysaccharide in Rat Pups

    PubMed Central

    Rodrigues, Fernanda S.; Souza, Mauren A.; Magni, Danieli V.; Ferreira, Ana Paula O.; Mota, Bibiana C.; Cardoso, Andreia M.; Paim, Mariana; Xavier, Léder L.; Ferreira, Juliano; Schetinger, Maria Rosa C.; Da Costa, Jaderson C.; Royes, Luiz Fernando F.; Fighera, Michele R.

    2013-01-01

    Background and Aims Glutaric aciduria type I (GA-I) is characterized by accumulation of glutaric acid (GA) and neurological symptoms, such as cognitive impairment. Although this disease is related to oxidative stress and inflammation, it is not known whether these processes facilitate the memory impairment. Our objective was to investigate the performance of rat pups chronically injected with GA and lipopolysaccharide (LPS) in spatial memory test, antioxidant defenses, cytokines levels, Na+, K+-ATPase activity, and hippocampal volume. We also evaluated the effect of N-acetylcysteine (NAC) on theses markers. Methods Rat pups were injected with GA (5umol g of body weight-1, subcutaneously; twice per day; from 5th to 28th day of life), and were supplemented with NAC (150mg/kg/day; intragastric gavage; for the same period). LPS (2mg/kg; E.coli 055 B5) or vehicle (saline 0.9%) was injected intraperitoneally, once per day, from 25th to 28th day of life. Oxidative stress and inflammatory biomarkers as well as hippocampal volume were assessed. Results GA caused spatial learning deficit in the Barnes maze and LPS potentiated this effect. GA and LPS increased TNF-α and IL-1β levels. The co-administration of these compounds potentiated the increase of IL-1β levels but not TNF-α levels in the hippocampus. GA and LPS increased TBARS (thiobarbituric acid-reactive substance) content, reduced antioxidant defenses and inhibited Na+, K+-ATPase activity. GA and LPS co-administration did not have additive effect on oxidative stress markers and Na+, K+ pump. The hippocampal volume did not change after GA or LPS administration. NAC protected against impairment of spatial learning and increase of cytokines levels. NAC Also protected against inhibition of Na+,K+-ATPase activity and oxidative markers. Conclusions These results suggest that inflammatory and oxidative markers may underlie at least in part of the neuropathology of GA-I in this model. Thus, NAC could represent a possible

  2. Ketogenic diet does not impair spatial ability controlled by the hippocampus in male rats.

    PubMed

    Fukushima, Atsushi; Ogura, Yuji; Furuta, Miyako; Kakehashi, Chiaki; Funabashi, Toshiya; Akema, Tatsuo

    2015-10-01

    A ketogenic diet was recently shown to reduce glutamate accumulation in synaptic vesicles, decreasing glutamate transmission. We questioned whether a ketogenic diet affects hippocampal function, as glutamate transmission is critically involved in visuospatial ability. In the present study, male Wistar rats were maintained on a ketogenic diet containing 10% protein and 90% fat with complements for 3 weeks to change their energy expenditure from glucose-dependent to fat-dependent. Control rats were fed a diet containing 10% protein, 10% fat, and 80% carbohydrates. The fat-dependent energy expenditure induced by the ketogenic diet led to decreased body weight and increased blood ketone production, though the rats in the two groups consumed the same number of calories. The ketogenic diet did not alter food preferences for the control or high-fat diet containing 10% protein, 45% fat, and 45% carbohydrates. Anxiety in the open field was not altered by ingestion the ketogenic diet. However, rats fed the ketogenic diet performed better in the Y-maze test than rats fed the control diet. No difference was observed between the two groups in the Morris water maze test. Finally, Western blot revealed that the hippocampal expression of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-type glutamate receptor subunit 1 (GluR1) was significantly increased in mice fed a ketogenic diet. These results suggest that hippocampal function is not impaired by a ketogenic diet and we speculate that the fat-dependent energy expenditure does not impair visuospatial ability. PMID:26111645

  3. Change detection in remote sensing images using modified polynomial regression and spatial multivariate alteration detection

    NASA Astrophysics Data System (ADS)

    Dianat, Rouhollah; Kasaei, Shohreh

    2009-11-01

    A new and efficient method for incorporating the spatiality into difference-based change detection (CD) algorithms is introduced in this paper. It uses the spatial derivatives of image pixels to extract spatial relations among them. Based on this methodology, the performances of two famous difference-based CD methods, conventional polynomial regression (CPR) and multivariate alteration detection (MAD), are improved and called modified polynomial regression (MPR) and spatial multivariate alteration detection (SMAD), respectively. Various quantitative and qualitative evaluations have shown the superiority of MPR over CPR and SMAD over MAD. Also, the superiority of SMAD over all mentioned CD algorithms is shown. Moreover, it has been proved that both proposed methods enjoy the affine invariance property.

  4. Exploring the relation between spatial configuration of buildings and remotely sensed temperatures

    NASA Astrophysics Data System (ADS)

    Myint, S. W.; Zheng, B.; Kaplan, S.; Huang, H.

    2013-12-01

    While the relationship between fractional cover of buildings and the UHI has been well studied, relationships of how spatial arrangements (e.g., clustered, dispersed) of buildings influence urban warming are not well understood. Since a diversity of spatial patterns can be observed under the same percentage of buildings cover, it is of great interest and importance to investigate the amount of variation in certain urban thermal feature such as surface temperature that is accounted for by the inclusion of spatial arrangement component. The various spatial arrangements of buildings cover can give rise to different urban thermal behaviors that may not be uncovered with the information of buildings fraction only, but can be captured to some extent using spatial analysis. The goal of this study is to examine how spatial arrangements of buildings influence and shape surface temperature in different urban settings. The study area selected is the Las-Vegas metropolitan area in Nevada, located in the Mojave Desert. An object-oriented approach was used to identify buildings using a Geoeye-1 image acquired on October 12, 2011. A spatial autocorrelation technique (i.e., Moran's I) that can measure spatial pattern (clustered, dispersed) was used to determine spatial configuration of buildings. A daytime temperature layer in degree Celsius, generated from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) image, was integrated with Moran's I values of building cover and building fractions to achieve the goals set in the study. To avoid uncertainty and properly evaluate if spatial pattern of buildings has an impact on urban warming, the relation between Moran's I values and surface temperatures was observed at different levels according to their fractions (e.g., 0-0.1, 0.5-0.6, 0.9-1). There is a negative correlation exists between spatial pattern of buildings and surface temperatures implying that dispersed building arrangements elevate surface temperatures

  5. Quantifying the spatio-temporal dynamics of woody plant encroachment using an integrative remote sensing, GIS, and spatial modeling approach

    NASA Astrophysics Data System (ADS)

    Buenemann, Michaela

    Despite a longstanding universal concern about and intensive research into woody plant encroachment (WPE)---the replacement of grasslands by shrub- and woodlands---our accumulated understanding of the process has either not been translated into sustainable rangeland management strategies or with only limited success. In order to increase our scientific insights into WPE, move us one step closer toward the sustainable management of rangelands affected by or vulnerable to the process, and identify needs for a future global research agenda, this dissertation presents an unprecedented critical, qualitative and quantitative assessment of the existing literature on the topic and evaluates the utility of an integrative remote sensing, GIS, and spatial modeling approach for quantifying the spatio-temporal dynamics of WPE. Findings from this research suggest that gaps in our current understanding of WPE and difficulties in devising sustainable rangeland management strategies are in part due to the complex spatio-temporal web of interactions between geoecological and anthropogenic variables involved in the process as well as limitations of presently available data and techniques. However, an in-depth analysis of the published literature also reveals that aforementioned problems are caused by two further crucial factors: the absence of information acquisition and reporting standards and the relative lack of long-term, large-scale, multi-disciplinary research efforts. The methodological framework proposed in this dissertation yields data that are easily standardized according to various criteria and facilitates the integration of spatially explicit data generated by a variety of studies. This framework may thus provide one common ground for scientists from a diversity of fields. Also, it has utility for both research and management. Specifically, this research demonstrates that the application of cutting-edge remote sensing techniques (Multiple Endmember Spectral Mixture

  6. Neurological effects of inorganic arsenic exposure: altered cysteine/glutamate transport, NMDA expression and spatial memory impairment

    PubMed Central

    Ramos-Chávez, Lucio A.; Rendón-López, Christian R. R.; Zepeda, Angélica; Silva-Adaya, Daniela; Del Razo, Luz M.; Gonsebatt, María E.

    2015-01-01

    Inorganic arsenic (iAs) is an important natural pollutant. Millions of individuals worldwide drink water with high levels of iAs. Chronic exposure to iAs has been associated with lower IQ and learning disabilities as well as memory impairment. iAs is methylated in tissues such as the brain generating mono and dimethylated species. iAs methylation requires cellular glutathione (GSH), which is the main antioxidant in the central nervous system (CNS). In humans, As species cross the placenta and are found in cord blood. A CD1 mouse model was used to investigate effects of gestational iAs exposure which can lead to oxidative damage, disrupted cysteine/glutamate transport and its putative impact in learning and memory. On postnatal days (PNDs) 1, 15 and 90, the expression of membrane transporters related to GSH synthesis and glutamate transport and toxicity, such as xCT, EAAC1, GLAST and GLT1, as well as LAT1, were analyzed. Also, the expression of the glutamate receptor N-methyl-D-aspartate (NMDAR) subunits NR2A and B as well as the presence of As species in cortex and hippocampus were investigated. On PND 90, an object location task was performed to associate exposure with memory impairment. Gestational exposure to iAs affected the expression of cysteine/glutamate transporters in cortex and hippocampus and induced a negative modulation of NMDAR NR2B subunit in the hippocampus. Behavioral tasks showed significant spatial memory impairment in males while the effect was marginal in females. PMID:25709567

  7. Diagnostic differentiation of mild cognitive impairment due to Alzheimer's disease using a hippocampus-dependent test of spatial memory.

    PubMed

    Moodley, Kuven; Minati, Ludovico; Contarino, Valeria; Prioni, Sara; Wood, Ruth; Cooper, Rebecca; D'Incerti, Ludovico; Tagliavini, Fabrizio; Chan, Dennis

    2015-08-01

    The hippocampus is one of the earliest brain regions affected in Alzheimer's disease (AD) and tests of hippocampal function have the potential to detect AD in its earliest stages. Given that the hippocampus is critically involved in allocentric spatial memory, this study applied a short test of spatial memory, the 4 Mountains Test (4MT), to determine whether test performance can differentiate mild cognitive impairment (MCI) patients with and without CSF biomarker evidence of underlying AD and whether the test can distinguish patients with MCI and mild AD dementia when applied in different cultural settings. Healthy controls (HC), patients with MCI, and mild AD dementia were recruited from study sites in UK and Italy. Study numbers were: HC (UK 20, Italy 10), MCI (UK 21, Italy 14), and AD (UK 11, Italy 9). Nineteen UK MCI patients were grouped into CSF biomarker-positive (MCI+, n = 10) and biomarker-negative (MCI-, n = 9) subgroups. Behavioral data were correlated with hippocampal volume and cortical thickness of the precuneus and posterior cingulate gyrus. Spatial memory was impaired in both UK and Italy MCI and AD patients. Test performance additionally differentiated between MCI+ and MCI- subgroups (P = 0.001). A 4MT score of ≤8/15 was associated with 100% sensitivity and 90% specificity for detection of early AD (MCI+ and mild AD dementia) in the UK population, and with 100% sensitivity and 50% specificity for detection of MCI and AD in the Italy sample. 4MT performance correlated with hippocampal volume in the UK population and cortical thickness of the precuneus in both study populations. In conclusion, performance on a hippocampus-sensitive test of spatial memory differentiates MCI due to AD with high diagnostic sensitivity and specificity. The observation that similar diagnostic sensitivity was obtained in two separate study populations, allied to the scalability and usability of the test in community memory clinics, supports future application of the 4MT

  8. [Gly14]-Humanin Protects Against Amyloid β Peptide-Induced Impairment of Spatial Learning and Memory in Rats.

    PubMed

    Yuan, Li; Liu, Xiao-Jie; Han, Wei-Na; Li, Qing-Shan; Wang, Zhao-Jun; Wu, Mei-Na; Yang, Wei; Qi, Jin-Shun

    2016-08-01

    Alzheimer disease (AD), a progressive neurodegenerative disorder, is characterized by cognitive decline and the accumulation of senile plaques in the brain. Amyloid β protein (Aβ) in the plaques is thought to be responsible for the memory loss in AD patients. [Gly14]-humanin (HNG), a derivative of humanin (HN), has much stronger neuroprotective effects than natural HN in vitro. However, clarification of the Aβ active center and the neuroprotective mechanism of HN still need in vivo evidence. The present study first compared the in vivo biological effects of three Aβ fragments (1-42, 31-35, and 35-31) on spatial memory in rats, and investigated the neuroprotective effects and molecular mechanisms of HNG. The results showed that intrahippocampal injection of Aβ1-42 and Aβ31-35 almost equally impaired spatial learning and memory, but the reversed sequence Aβ35-31 did not have any effect; a high dose of Aβ31-35 (20 nmol) produced a more detrimental response than a low dose (2 nmol); Aβ31-35 injection also disrupted gene and protein expression in the hippocampus, with up-regulation of caspase3 and down-regulation of STAT3; pretreatment with HNG not only protected spatial memory but also rescued STAT3 from Aβ-induced disruption; and the neuroprotective effects of HNG were effectively counteracted by genistein, a specific tyrosine kinase inhibitor. These results clearly show that sequence 31-35 in Aβ is the shortest active center responsible for the neurotoxicity of Aβ from molecule to behavior; and HNG protects spatial learning and memory in rats against Aβ-induced insults; and probably involves the activation of tyrosine kinases and subsequent beneficial modulation of STAT3 and caspase3. PMID:27306655

  9. Spatial Memory and Long-Term Object Recognition Are Impaired by Circadian Arrhythmia and Restored by the GABAAAntagonist Pentylenetetrazole

    PubMed Central

    Ruby, Norman F.; Fernandez, Fabian; Garrett, Alex; Klima, Jessy; Zhang, Pei; Sapolsky, Robert; Heller, H. Craig

    2013-01-01

    Performance on many memory tests varies across the day and is severely impaired by disruptions in circadian timing. We developed a noninvasive method to permanently eliminate circadian rhythms in Siberian hamsters (Phodopussungorus) so that we could investigate the contribution of the circadian system to learning and memory in animals that are neurologically and genetically intact. Male and female adult hamsters were rendered arrhythmic by a disruptive phase shift protocol that eliminates cycling of clock genes within the suprachiasmatic nucleus (SCN), but preserves sleep architecture. These arrhythmic animals have deficits in spatial working memory and in long-term object recognition memory. In a T-maze, rhythmic control hamsters exhibited spontaneous alternation behavior late in the day and at night, but made random arm choices early in the day. By contrast, arrhythmic animals made only random arm choices at all time points. Control animals readily discriminated novel objects from familiar ones, whereas arrhythmic hamsters could not. Since the SCN is primarily a GABAergic nucleus, we hypothesized that an arrhythmic SCN could interfere with memory by increasing inhibition in hippocampal circuits. To evaluate this possibility, we administered the GABAA antagonist pentylenetetrazole (PTZ; 0.3 or 1.0 mg/kg/day) to arrhythmic hamsters for 10 days, which is a regimen previously shown to produce long-term improvements in hippocampal physiology and behavior in Ts65Dn (Down syndrome) mice. PTZ restored long-term object recognition and spatial working memory for at least 30 days after drug treatment without restoring circadian rhythms. PTZ did not augment memory in control (entrained) animals, but did increase their activity during the memory tests. Our findings support the hypothesis that circadian arrhythmia impairs declarative memory by increasing the relative influence of GABAergic inhibition in the hippocampus. PMID:24009680

  10. Spatial Heterogeneity of Leaf Area Index (LAI) and Its Temporal Course on Arable Land: Combining Field Measurements, Remote Sensing and Simulation in a Comprehensive Data Analysis Approach (CDAA)

    PubMed Central

    Korres, Wolfgang; Montzka, Carsten; Fiener, Peter; Wilken, Florian; Stadler, Anja; Waldhoff, Guido; Schneider, Karl

    2016-01-01

    The ratio of leaf area to ground area (leaf area index, LAI) is an important state variable in ecosystem studies since it influences fluxes of matter and energy between the land surface and the atmosphere. As a basis for generating temporally continuous and spatially distributed datasets of LAI, the current study contributes an analysis of its spatial variability and spatial structure. Soil-vegetation-atmosphere fluxes of water, carbon and energy are nonlinearly related to LAI. Therefore, its spatial heterogeneity, i.e., the combination of spatial variability and structure, has an effect on simulations of these fluxes. To assess LAI spatial heterogeneity, we apply a Comprehensive Data Analysis Approach that combines data from remote sensing (5 m resolution) and simulation (150 m resolution) with field measurements and a detailed land use map. Test area is the arable land in the fertile loess plain of the Rur catchment on the Germany-Belgium-Netherlands border. LAI from remote sensing and simulation compares well with field measurements. Based on the simulation results, we describe characteristic crop-specific temporal patterns of LAI spatial variability. By means of these patterns, we explain the complex multimodal frequency distributions of LAI in the remote sensing data. In the test area, variability between agricultural fields is higher than within fields. Therefore, spatial resolutions less than the 5 m of the remote sensing scenes are sufficient to infer LAI spatial variability. Frequency distributions from the simulation agree better with the multimodal distributions from remote sensing than normal distributions do. The spatial structure of LAI in the test area is dominated by a short distance referring to field sizes. Longer distances that refer to soil and weather can only be derived from remote sensing data. Therefore, simulations alone are not sufficient to characterize LAI spatial structure. It can be concluded that a comprehensive picture of LAI spatial

  11. Spatial Heterogeneity of Leaf Area Index (LAI) and Its Temporal Course on Arable Land: Combining Field Measurements, Remote Sensing and Simulation in a Comprehensive Data Analysis Approach (CDAA).

    PubMed

    Reichenau, Tim G; Korres, Wolfgang; Montzka, Carsten; Fiener, Peter; Wilken, Florian; Stadler, Anja; Waldhoff, Guido; Schneider, Karl

    2016-01-01

    The ratio of leaf area to ground area (leaf area index, LAI) is an important state variable in ecosystem studies since it influences fluxes of matter and energy between the land surface and the atmosphere. As a basis for generating temporally continuous and spatially distributed datasets of LAI, the current study contributes an analysis of its spatial variability and spatial structure. Soil-vegetation-atmosphere fluxes of water, carbon and energy are nonlinearly related to LAI. Therefore, its spatial heterogeneity, i.e., the combination of spatial variability and structure, has an effect on simulations of these fluxes. To assess LAI spatial heterogeneity, we apply a Comprehensive Data Analysis Approach that combines data from remote sensing (5 m resolution) and simulation (150 m resolution) with field measurements and a detailed land use map. Test area is the arable land in the fertile loess plain of the Rur catchment on the Germany-Belgium-Netherlands border. LAI from remote sensing and simulation compares well with field measurements. Based on the simulation results, we describe characteristic crop-specific temporal patterns of LAI spatial variability. By means of these patterns, we explain the complex multimodal frequency distributions of LAI in the remote sensing data. In the test area, variability between agricultural fields is higher than within fields. Therefore, spatial resolutions less than the 5 m of the remote sensing scenes are sufficient to infer LAI spatial variability. Frequency distributions from the simulation agree better with the multimodal distributions from remote sensing than normal distributions do. The spatial structure of LAI in the test area is dominated by a short distance referring to field sizes. Longer distances that refer to soil and weather can only be derived from remote sensing data. Therefore, simulations alone are not sufficient to characterize LAI spatial structure. It can be concluded that a comprehensive picture of LAI spatial

  12. Impaired Sarcoplasmic Reticulum Calcium Uptake and Release Promote Electromechanically and Spatially Discordant Alternans: A Computational Study

    PubMed Central

    Weinberg, Seth H.

    2016-01-01

    Cardiac electrical dynamics are governed by cellular-level properties, such as action potential duration (APD) restitution and intracellular calcium (Ca) handling, and tissue-level properties, including conduction velocity restitution and cell–cell coupling. Irregular dynamics at the cellular level can lead to instabilities in cardiac tissue, including alternans, a beat-to-beat alternation in the action potential and/or the intracellular Ca transient. In this study, we incorporate a detailed single cell coupled map model of Ca cycling and bidirectional APD-Ca coupling into a spatially extended tissue model to investigate the influence of sarcoplasmic reticulum (SR) Ca uptake and release properties on alternans and conduction block. We find that an intermediate SR Ca uptake rate and larger SR Ca release resulted in the widest range of stimulus periods that promoted alternans. However, both reduced SR Ca uptake and release promote arrhythmogenic spatially and electromechanically discordant alternans, suggesting a complex interaction between SR Ca handling and alternans characteristics at the cellular and tissue level. PMID:27385917

  13. KCNQ/Kv7 channel activator flupirtine protects against acute stress-induced impairments of spatial memory retrieval and hippocampal LTP in rats.

    PubMed

    Li, C; Huang, P; Lu, Q; Zhou, M; Guo, L; Xu, X

    2014-11-01

    Spatial memory retrieval and hippocampal long-term potentiation (LTP) are impaired by stress. KCNQ/Kv7 channels are closely associated with memory and the KCNQ/Kv7 channel activator flupirtine represents neuroprotective effects. This study aims to test whether KCNQ/Kv7 channel activation prevents acute stress-induced impairments of spatial memory retrieval and hippocampal LTP. Rats were placed on an elevated platform in the middle of a bright room for 30 min to evoke acute stress. The expression of KCNQ/Kv7 subunits was analyzed at 1, 3 and 12 h after stress by Western blotting. Spatial memory was examined by the Morris water maze (MWM) and the field excitatory postsynaptic potential (fEPSP) in the hippocampal CA1 area was recorded in vivo. Acute stress transiently decreased the expression of KCNQ2 and KCNQ3 in the hippocampus. Acute stress impaired the spatial memory retrieval and hippocampal LTP, the KCNQ/Kv7 channel activator flupirtine prevented the impairments, and the protective effects of flupirtine were blocked by XE-991 (10,10-bis(4-Pyridinylmethyl)-9(10H)-anthracenone), a selective KCNQ channel blocker. Furthermore, acute stress decreased the phosphorylation of glycogen synthase kinase-3β (GSK-3β) at Ser9 in the hippocampus, and flupirtine inhibited the reduction. These results suggest that the KCNQ/Kv7 channels may be a potential target for protecting both hippocampal synaptic plasticity and spatial memory retrieval from acute stress influences. PMID:25234320

  14. Soluble amyloid beta oligomers block the learning-induced increase in hippocampal sharp wave-ripple rate and impair spatial memory formation

    PubMed Central

    Nicole, Olivier; Hadzibegovic, Senka; Gajda, Judyta; Bontempi, Bruno; Bem, Tiaza; Meyrand, Pierre

    2016-01-01

    Post-learning hippocampal sharp wave-ripples (SWRs) generated during slow wave sleep are thought to play a crucial role in memory formation. While in Alzheimer’s disease, abnormal hippocampal oscillations have been reported, the functional contribution of SWRs to the typically observed spatial memory impairments remains unclear. These impairments have been related to degenerative synaptic changes produced by soluble amyloid beta oligomers (Aβos) which, surprisingly, seem to spare the SWR dynamics during routine behavior. To unravel a potential effect of Aβos on SWRs in cognitively-challenged animals, we submitted vehicle- and Aβo-injected mice to spatial recognition memory testing. While capable of forming short-term recognition memory, Aβ mice exhibited faster forgetting, suggesting successful encoding but an inability to adequately stabilize and/or retrieve previously acquired information. Without prior cognitive requirements, similar properties of SWRs were observed in both groups. In contrast, when cognitively challenged, the post-encoding and -recognition peaks in SWR occurrence observed in controls were abolished in Aβ mice, indicating impaired hippocampal processing of spatial information. These results point to a crucial involvement of SWRs in spatial memory formation and identify the Aβ-induced impairment in SWRs dynamics as a disruptive mechanism responsible for the spatial memory deficits associated with Alzheimer’s disease. PMID:26947247

  15. Modeling the spatial distribution of above-ground carbon in Mexican coniferous forests using remote sensing and a geostatistical approach

    NASA Astrophysics Data System (ADS)

    Galeana-Pizaña, J. Mauricio; López-Caloca, Alejandra; López-Quiroz, Penélope; Silván-Cárdenas, José Luis; Couturier, Stéphane

    2014-08-01

    Forest conservation is considered an option for mitigating the effect of greenhouse gases on global climate, hence monitoring forest carbon pools at global and local levels is important. The present study explores the capability of remote-sensing variables (vegetation indices and textures derived from SPOT-5; backscattering coefficient and interferometric coherence of ALOS PALSAR images) for modeling the spatial distribution of above-ground biomass in the Environmental Conservation Zone of Mexico City. Correlation and spatial autocorrelation coefficients were used to select significant explanatory variables in fir and pine forests. The correlation for interferometric coherence in HV polarization was negative, with correlations coefficients r = -0.83 for the fir and r = -0.75 for the pine forests. Regression-kriging showed the least root mean square error among the spatial interpolation methods used, with 37.75 tC/ha for fir forests and 29.15 tC/ha for pine forests. The results showed that a hybrid geospatial method, based on interferometric coherence data and a regression-kriging interpolator, has good potential for estimating above-ground biomass carbon.

  16. Haploinsufficiency of VGluT1 but not VGluT2 impairs extinction of spatial preference and response suppression.

    PubMed

    Callaerts-Vegh, Zsuzsanna; Moechars, Diederik; Van Acker, Nathalie; Daneels, Guy; Goris, Ilse; Leo, Sandra; Naert, Arne; Meert, Theo; Balschun, Detlef; D'Hooge, Rudi

    2013-05-15

    The excitatory neurotransmitter l-glutamate is transported into synaptic vesicles by vesicular glutamate transporters (VGluTs) to transmit glutamatergic signals. Changes in their expression have been linked to various brain disorders including schizophrenia, Parkinson's, and Alzheimer's disease. Deleting either the VGluT1 or VGluT2 gene leads to profound developmental and neurological complications and early death, but mice heterozygous for VGluT1 or VGluT2 are viable and thrive. Acquisition, retention and extinction of conditioned visuospatial and emotional responses were compared between VGluT1(+/-) and VGluT2(+/-) mice, and their wildtype littermates, using different water maze procedures, appetitive scheduled conditioning, and conditioned fear protocols. The distinct brain expression profiles of the VGluT1 and -2 isoforms particularly in telencephalic structures, such as neocortex, hippocampus and striatum, are reflected in very specific behavioral changes. VGluT2(+/-) mice were unimpaired in spatial learning tasks and fear extinction. Conversely, VGluT1(+/-) mice displayed spatial extinction learning deficits and markedly impaired fear extinction. These data indicate that VGluT1, but not VGluT2, plays a role in the neural processes underlying inhibitory learning. PMID:23396167

  17. Impaired retention of spatial memory after transection of longitudinally oriented axons of hippocampal CA3 pyramidal cells

    NASA Astrophysics Data System (ADS)

    Steffenach, Hill-Aina; Sloviter, Robert S.; Moser, Edvard I.; Moser, May-Britt

    2002-03-01

    Longitudinally oriented axon collaterals of CA3 pyramidal cells may be critical for integrating distributed information in the hippocampus. To investigate the possible role of this pathway in the retention of spatial memory, we made a single transversely oriented cut through the dorsal CA3 region of each hippocampus. Although the lesion involved <3% of the hippocampal volume, it nonetheless disrupted memory retention in a water maze in preoperatively trained rats. New learning in a different water maze was attenuated. No significant impairment occurred in rats with longitudinally oriented cuts, or in animals with ibotenic acid-induced lesions of similar magnitude. To characterize the effect of a focal lesion on the integrity of longitudinally projecting axons, we stained degenerating cells and fibers in rats with unilateral CA3 transections by using FluoroJade-B. Degenerating terminals were seen across a wide region posterior to the cut, and were present in the strata of areas CA3 and CA1 that are innervated by CA3 pyramidal cells. These results suggest that the integrity of longitudinally oriented, translamellar axons of CA3 pyramidal cells may be necessary for efficient acquisition and retention of spatial memory.

  18. Impaired retention of spatial memory after transection of longitudinally oriented axons of hippocampal CA3 pyramidal cells

    PubMed Central

    Steffenach, Hill-Aina; Sloviter, Robert S.; Moser, Edvard I.; Moser, May-Britt

    2002-01-01

    Longitudinally oriented axon collaterals of CA3 pyramidal cells may be critical for integrating distributed information in the hippocampus. To investigate the possible role of this pathway in the retention of spatial memory, we made a single transversely oriented cut through the dorsal CA3 region of each hippocampus. Although the lesion involved <3% of the hippocampal volume, it nonetheless disrupted memory retention in a water maze in preoperatively trained rats. New learning in a different water maze was attenuated. No significant impairment occurred in rats with longitudinally oriented cuts, or in animals with ibotenic acid-induced lesions of similar magnitude. To characterize the effect of a focal lesion on the integrity of longitudinally projecting axons, we stained degenerating cells and fibers in rats with unilateral CA3 transections by using FluoroJade-B. Degenerating terminals were seen across a wide region posterior to the cut, and were present in the strata of areas CA3 and CA1 that are innervated by CA3 pyramidal cells. These results suggest that the integrity of longitudinally oriented, translamellar axons of CA3 pyramidal cells may be necessary for efficient acquisition and retention of spatial memory. PMID:11867718

  19. Impaired Spatial Learning Memory after Isoflurane Anesthesia or Appendectomy in Aged Mice is Associated with Microglia Activation

    PubMed Central

    Wang, Hui-Lin; Ma, Rui-Hua; Fang, Hao; Xue, Zhang-Gang; Liao, Qing-Wu

    2015-01-01

    Postoperative cognitive dysfunction (POCD) has been one of the most common problems in elderly patients following surgery. But the specific mechanism of POCD is still not clear. To further understand the reason of these postoperative behavioral deficits, we evaluated the spatial learning memory of both adult (3 months) and aged (18 months) male mice, 3 or 28 days after isoflurane (Iso) exposure for two hours or appendectomy (App). Hippocampal microglia activation and IL-1β, TNF-α, and IFN-γ expression were also evaluated at day 3, day 14 and day 28 after Iso exposure or appendectomy. Results showed that spatial learning memory of aged, but not adult, mice was impaired after Iso exposure or appendectomy, accompanied with more hippocampal microglia activation and IL-1β, TNF-α, and IFN-γ overexpression. These findings suggest that the cognitive deficits of elderly patients who have undergone surgeries are quite possibly caused by hippocampal microglia overactivation and the subsequent inflammation. PMID:26380557

  20. Neonatal methylphenidate does not impair adult spatial learning in the Morris water maze in rats.

    PubMed

    Amos-Kroohs, Robyn M; Williams, Michael T; Vorhees, Charles V

    2011-09-20

    Methylphenidate (MPD) is the most prescribed drug for attention deficit hyperactivity disorder. Licit and illicit use also occurs during pregnancy, however the effects from this use on offspring development are unknown. To model late gestational exposure, Sprague-Dawley litters were treated with 0, 5, 10, 20, or 30mg/kg×4/day every 2h with MPD on postnatal days 11-20 (within-litter design; days chosen to be comparable to human third trimester brain development). During treatment, body weights were decreased in MPD-treated groups; weight recovery occurred in all but the MPD-30 group by start of testing. MPD-treated rats showed no changes in anxiety (elevated zero maze), swimming ability (straight channel swimming), or spatial learning/reference memory (Morris water maze). MPD does not appear to pose a risk to these CNS functions after exposure during a stage of rat development analogous to third trimester human brain development. PMID:21798318

  1. Spatial And Temporal Trends Of Organic Pollutants In Vegetation From Remote And Rural Areas

    PubMed Central

    Bartrons, Mireia; Catalan, Jordi; Penuelas, Josep

    2016-01-01

    Persistent organic pollutants (POPs) and polycyclic aromatic hydrocarbons (PAHs) used in agricultural, industrial, and domestic applications are widely distributed and bioaccumulate in food webs, causing adverse effects to the biosphere. A review of published data for 1977–2015 for a wide range of vegetation around the globe indicates an extensive load of pollutants in vegetation. On a global perspective, the accumulation of POPs and PAHs in vegetation depends on the industrialization history across continents and distance to emission sources, beyond organism type and climatic variables. International regulations initially reduced the concentrations of POPs in vegetation in rural areas, but concentrations of HCB, HCHs, and DDTs at remote sites did not decrease or even increased over time, pointing to a remobilization of POPs from source areas to remote sites. The concentrations of compounds currently in use, PBDEs and PAHs, are still increasing in vegetation. Differential congener specific accumulation is mostly determined by continent—in accordance to the different regulations of HCHs, PCBs and PBDEs in different countries—and by plant type (PAHs). These results support a concerning general accumulation of toxic pollutants in most ecosystems of the globe that for some compounds is still far from being mitigated in the near future. PMID:27146722

  2. Spatial and interspecific variation of accumulated trace metals between remote and urbane dwelling birds of Pakistan.

    PubMed

    Abbasi, Naeem Akhtar; Khan, Muhammad Usman; Jaspers, Veerle Leontina Bernard; Chaudhry, Muhammad Jamshed Iqbal; Malik, Riffat Naseem

    2015-03-01

    The current study was designed to evaluate the hypothesis that birds of urbanized and/or industrialized origin depict higher metal accumulation as compared to remote dwellers. We selected seven representative species from three families (Anatidae, Motacillidae and Sturnidae) at two different locations; Baroghil valley (remote location) and Soan valley (urbanized location) of Pakistan and analyzed the concentrations of 8 metals Pb, Cd, Cr, Ni, Cu, Mn, Fe and Zn in feathers of these species. Feathers from Soan valley which is under higher anthropogenic influence exhibited significantly (P<0.001) higher metal concentrations when compared with the feathers of the same species at Baroghil valley which has negligible anthropogenic input. Terrestrial birds of the Baroghil valley revealed greater metal loads than aquatic birds while at Soan valley it was vice versa. In general, elevated concentrations of metals were recorded in insectivorous species as compared to omnivorous species. Within each location, species belonging to Anatidae and Motacillidae revealed similar metal contamination patterns. Principal component Analysis (PCA) based on correlation matrices depicted a clear tendency of metals towards the species originating from areas with greater pollution load (Soan valley) than relatively undisturbed sites (Baroghil valley) and hence corroborated our hypothesis. The pattern of metal accumulation in feathers of both the locations suggested that there may be a flux of migration between the two regions and/or trans-boundary movement of pollutants/metals, which either singly or synergistically influence the overall metal profile in the studied bird species. PMID:25528378

  3. Galvanic vestibular stimulation impairs cell proliferation and neurogenesis in the rat hippocampus but not spatial memory.

    PubMed

    Zheng, Yiwen; Geddes, Lisa; Sato, Go; Stiles, Lucy; Darlington, Cynthia L; Smith, Paul F

    2014-05-01

    Galvanic vestibular stimulation (GVS) is a method of activating the peripheral vestibular system using direct current that is widely employed in clinical neurological testing. Since movement is recognized to stimulate hippocampal neurogenesis and movement is impossible without activation of the vestibular system, we speculated that activating the vestibular system in rats while minimizing movement, by delivering GVS under anesthesia, would affect hippocampal cell proliferation and neurogenesis, and spatial memory. Compared with the sham control group, the number of cells incorporating the DNA replication marker, bromodeoxyuridine (BrdU), was significantly reduced in the bilateral hippocampi in both the cathode left-anode right and cathode right-anode left stimulation groups (P ≤ 0.0001). The majority of the BrdU(+ve) cells co-expressed Ki-67, a marker for the S phase of the cell cycle, suggesting that these BrdU(+ve) cells were still in the cell cycle; however, there was no significant difference in the degree of co-labeling between the two stimulation groups. Single labeling for doublecortin (DCX), a marker of immature neurons, showed that while there was no significant difference between the different groups in the number of DCX(+ve) cells in the right dentate gryus, in the left dentate gyrus there was a significant decrease in the cathode left-anode right group compared with the sham controls (P ≤ 0.03). Nonetheless, when animals were tested in place recognition, object exploration and Morris water maze tasks, there were no significant differences between the GVS groups and the sham controls. These results suggest that GVS can have striking effects on cell proliferation and possibly neurogenesis in the hippocampus, without affecting spatial memory. PMID:24449222

  4. Chronic Stress Impairs Prefrontal Cortex-Dependent Response Inhibition and Spatial Working Memory

    PubMed Central

    Mika, Agnieszka; Mazur, Gabriel J.; Hoffman, Ann N.; Talboom, Joshua S.; Bimonte-Nelson, Heather A.; Sanabria, Federico; Conrad, Cheryl D.

    2012-01-01

    Chronic stress leads to neurochemical and structural alterations in the prefrontal cortex (PFC) that correspond to deficits in PFC-mediated behaviors. The present study examined the effects of chronic restraint stress on response inhibition (using a response-withholding task, fixed-minimum interval schedule of reinforcement, or FMI), and working memory (using a radial arm water maze, RAWM). Adult male Sprague Dawley rats were first trained on the RAWM and subsequently trained on FMI. Following acquisition of FMI, rats were assigned to a restraint stress (6h/d/28d in wire mesh restrainers) or control condition. Immediately after chronic stress, rats were tested on FMI and subsequently on RAWM. FMI results suggest that chronic stress reduces response inhibition capacity and motivation to initiate the task on selective conditions when food reward was not obtained on the preceding trial. RAWM results suggest that chronic stress produces transient deficits in working memory without altering previously consolidated reference memory. Behavioral measures from FMI failed to correlate with metrics from RAWM except for one in which changes in FMI timing precision negatively correlated with changes in RAWM working memory errors for the controls, a finding that was not observed following chronic stress. Fisher’s r to z transformation revealed no significant differences between control and stress with correlation coefficients. These findings are the first to show that chronic stress impairs both response inhibition and working memory, two behaviors that have never been direct compared within the same animals following chronic stress, using FMI, an appetitive task, and RAWM, a non-appetitive task. PMID:22905921

  5. Role of Synaptic Structural Plasticity in Impairments of Spatial Learning and Memory Induced by Developmental Lead Exposure in Wistar Rats

    PubMed Central

    Han, Xiaojie; Hu, Xiaoxia; Gu, Huaiyu; Chen, Yilin; Wei, Qing; Hu, Qiansheng

    2014-01-01

    Lead (Pb) is found to impair cognitive function. Synaptic structural plasticity is considered to be the physiological basis of synaptic functional plasticity and has been recently found to play important roles in learning and memory. To study the effect of Pb on spatial learning and memory at different developmental stages, and its relationship with alterations of synaptic structural plasticity, postnatal rats were randomly divided into three groups: Control; Pre-weaning Pb (Parents were exposed to 2 mM PbCl2 3 weeks before mating until weaning of pups); Post-weaning Pb (Weaned pups were exposed to 2 mM PbCl2 for 9 weeks). The spatial learning and memory of rats was measured by Morris water maze (MWM) on PND 85–90. Rat pups in Pre-weaning Pb and Post-weaning Pb groups performed significantly worse than those in Control group (p<0.05). However, there was no significant difference in the performance of MWM between the two Pb-exposure groups. Before MWM (PND 84), the number of neurons and synapses significantly decreased in Pre-weaning Pb group, but not in Post-weaning Pb group. After MWM (PND 91), the number of synapses in Pre-weaning Pb group increased significantly, but it was still less than that of Control group (p<0.05); the number of synapses in Post-weaning Pb group was also less than that of Control group (p<0.05), although the number of synapses has no differences between Post-weaning Pb and Control groups before MWM. In both Pre-weaning Pb and Post-weaning Pb groups, synaptic structural parameters such as thickness of postsynaptic density (PSD), length of synaptic active zone and synaptic curvature increased significantly while width of synaptic cleft decreased significantly compared to Control group (p<0.05). Our data demonstrated that both early and late developmental Pb exposure impaired spatial learning and memory as well as synaptic structural plasticity in Wistar rats. PMID:25536363

  6. Estimating spatial veriability in atmospheric properties over remotely sensed land-surface conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper investigates the spatial relationships between land-surface fluxes and near-surface atmospheric properties (AP), and the potential errors in flux estimation due to homogeneous atmospheric inputs over heterogeneous landscapes. A Large Eddy Simulation (LES) model is coupled to a surface ene...

  7. Remote Spatial Memory and the Hippocampus: Effect of Early and Extensive Training in the Radial Maze

    ERIC Educational Resources Information Center

    Ramos, Juan M. J.

    2009-01-01

    In a previous study we showed a temporally graded retrograde amnesia after hippocampal lesions when rats learned a spatial reference memory task in which two types of signals simultaneously indicated the goal arm (shape of the experimental room and extramaze landmarks). To investigate the effect that the navigational demands of the task have on…

  8. Advanced Remote-sensing Imaging Emission Spectrometer (ARIES): AIRS Spectral Resolution with MODIS Spatial Resolution

    NASA Technical Reports Server (NTRS)

    Pagano, Thomas S.; Chahine, Moustafa T.; Aumann, Hartmut H.; OCallaghan, Fred G.; Broberg, Steve E.

    2006-01-01

    This paper describes a space based instrument concept that will provide scientists with data needed to support key ongoing and future Earth System Science investigations. The measurement approach builds on the observations made by AIRS and MODIS and exceeds their capability with improved spatial and spectral resolution. This paper describes the expected products and the instrument concept that can meet those requirements.

  9. An intercomparison of remotely sensed soil moisture products at various spatial scales over the Iberian penisula

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil moisture (SM) can be retrieved from active microwave (AM)-, passive microwave (PM)- and thermal infrared (TIR)-observations, each having their unique spatial- and temporal-coverage. A limitation of TIR-based SM retrievals is its dependency on cloud-free conditions, while microwave retrievals ar...

  10. Characterizing the multi–scale spatial structure of remotely sensed evapotranspiration with information theory

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A more thorough understanding of the multi-scale spatial structure of land surface heterogeneity will enhance understanding of the relationships and feedbacks between land surface conditions,mass and energy exchanges between the surface and the atmosphere, and regional meteorological and climatologi...

  11. Remote sensing of seasonal variability of fractional vegetation cover and its object-based spatial pattern analysis over mountain areas

    NASA Astrophysics Data System (ADS)

    Yang, Guijun; Pu, Ruiliang; Zhang, Jixian; Zhao, Chunjiang; Feng, Haikuan; Wang, Jihua

    2013-03-01

    Fractional vegetation cover (FVC) is an important indicator of mountain ecosystem status. A study on the seasonal changes of FVC can be beneficial for regional eco-environmental security, which contributes to the assessment of mountain ecosystem recovery and supports mountain forest planning and landscape reconstruction around megacities, for example, Beijing, China. Remote sensing has been demonstrated to be one of the most powerful and feasible tools for the investigation of mountain vegetation. However, topographic and atmospheric effects can produce enormous errors in the quantitative retrieval of FVC data from satellite images of mountainous areas. Moreover, the most commonly used analysis approach for assessing FVC seasonal fluctuations is based on per-pixel analysis regardless of the spatial context, which results in pixel-based FVC values that are feasible for landscape and ecosystem applications. To solve these problems, we proposed a new method that incorporates the use of a revised physically based (RPB) model to correct both atmospheric and terrain-caused illumination effects on Landsat images, an improved vegetation index (VI)-based technique for estimating the FVC, and an adaptive mean shift approach for object-based FVC segmentation. An array of metrics for segmented FVC analyses, including a variety of area metrics, patch metrics, shape metrics and diversity metrics, was generated. On the basis of the individual segmented FVC values and landscape metrics from multiple images of different dates, remote sensing of the seasonal variability of FVC was conducted over the mountainous area of Beijing, China. The experimental results indicate that (a) the mean value of the RPB-NDVI in all seasons was increased by approximately 10% compared with that of the atmospheric correction-NDVI; (b) a strong consistency was demonstrated between ground-based FVC observations and FVC estimated through remote sensing technology (R2 = 0.8527, RMSE = 0.0851); and (c

  12. A Comparative Study of Sampling Analysis in the Scene Classification of Optical High-Spatial Resolution Remote Sensing Imagery

    NASA Astrophysics Data System (ADS)

    Hu, Jingwen; Xia, Gui-Song; Hu, Fan; Zhang, Liangpei

    2015-11-01

    Scene classification is a key problem in the interpretation of high-resolution remote sensing imagery. Many state-of-the-art methods, e.g. bag-of-visual-words model and its variants, the topic models as well as deep learning-based approaches, share similar procedures: patch sampling, feature description/learning and classification. Patch sampling is the first and a key procedure which has a great influence on the results. In the literature, many different sampling strategies have been used, {e.g. dense sampling, random sampling, keypoint-based sampling and saliency-based sampling, etc. However, it is still not clear which sampling strategy is suitable for the scene classification of high-resolution remote sensing images. In this paper, we comparatively study the effects of different sampling strategies under the scenario of scene classification of high-resolution remote sensing images. We divide the existing sampling methods into two types: dense sampling and sparse sampling, the later of which includes random sampling, keypoint-based sampling and various saliency-based sampling proposed recently. In order to compare their performances, we rely on a standard bag-of-visual-words model to construct our testing scheme, owing to their simplicity, robustness and efficiency. The experimental results on two commonly used datasets show that dense sampling has the best performance among all the strategies but with high spatial and computational complexity, random sampling gives better or comparable results than other sparse sampling methods, like the sophisticated multi-scale key-point operators and the saliency-based methods which are intensively studied and commonly used recently.

  13. Temporal and spatial change in coastal ecosystems using remote sensing: Example with Florida Bay, USA, emphasizing AVHRR imagery

    SciTech Connect

    Stumpf, R.P.; Frayer, M.L.

    1997-06-01

    Florida Bay, at the southern tip of Florida, USA, has undergone dramatic changes in recent years. Following seagrass dieoffs starting in the late 1980`s, both algal blooms and high turbidity (the latter from resuspended sediments) have been reported as more common in the Bay. Remotely sensed data, particularly from the AVHRR (advanced very high resolution radiometer), can provide information on conditions prior to the start of monitoring programs as well as provide additional spatial detail on water clarity and particulate loads in this estuary . The AVHRR record currently available to us consists of over 600 usable scenes from December, 1989. Comparisons with field data have provided relationships with light attenuation, total suspended solids, and other turbidity measures. The imagery shows the seasonal change in turbidity resulting from high winds associated with winter cold fronts. Over the seven-year record, areas of clear water have decreased in the north-central Bay, while expanding in the southwestern Bay.

  14. Spatial distribution and ecological environment analysis of great gerbil in Xinjiang Plague epidemic foci based on remote sensing

    NASA Astrophysics Data System (ADS)

    Gao, Mengxu; Li, Qun; Cao, Chunxiang; Wang, Juanle

    2014-03-01

    Yersinia pestis (Plague bacterium) from great gerbil was isolated in 2005 in Xinjiang Dzungarian Basin, which confirmed the presence of the plague epidemic foci. This study analysed the spatial distribution and suitable habitat of great gerbil based on the monitoring data of great gerbil from Chinese Center for Disease Control and Prevention, as well as the ecological environment elements obtained from remote sensing products. The results showed that: (1) 88.5% (277/313) of great gerbil distributed in the area of elevation between 200 and 600 meters. (2) All the positive points located in the area with a slope of 0-3 degree, and the sunny tendency on aspect was not obvious. (3) All 313 positive points of great gerbil distributed in the area with an average annual temperature from 5 to 11 °C, and 165 points with an average annual temperature from 7 to 9 °C. (4) 72.8% (228/313) of great gerbil survived in the area with an annual precipitation of 120-200mm. (5) The positive points of great gerbil increased correspondingly with the increasing of NDVI value, but there is no positive point when NDVI is higher than 0.521, indicating the suitability of vegetation for great gerbil. This study explored a broad and important application for the monitoring and prevention of plague using remote sensing and geographic information system.

  15. Correction to ``Extracting Man-Made Objects From High Spatial Resolution Remote Sensing Images via Fast Level Set Evolutions''

    NASA Astrophysics Data System (ADS)

    Li, Zhongbin; Shi, Wenzhong; Wang, Qunming; Miao, Zelang

    2015-10-01

    Object extraction from remote sensing images has long been an intensive research topic in the field of surveying and mapping. Most existing methods are devoted to handling just one type of object and little attention has been paid to improving the computational efficiency. In recent years, level set evolution (LSE) has been shown to be very promising for object extraction in the community of image processing and computer vision because it can handle topological changes automatically while achieving high accuracy. However, the application of state-of-the-art LSEs is compromised by laborious parameter tuning and expensive computation. In this paper, we proposed two fast LSEs for man-made object extraction from high spatial resolution remote sensing images. The traditional mean curvature-based regularization term is replaced by a Gaussian kernel and it is mathematically sound to do that. Thus a larger time step can be used in the numerical scheme to expedite the proposed LSEs. In contrast to existing methods, the proposed LSEs are significantly faster. Most importantly, they involve much fewer parameters while achieving better performance. The advantages of the proposed LSEs over other state-of-the-art approaches have been verified by a range of experiments.

  16. A spectral-structural bag-of-features scene classifier for very high spatial resolution remote sensing imagery

    NASA Astrophysics Data System (ADS)

    Zhao, Bei; Zhong, Yanfei; Zhang, Liangpei

    2016-06-01

    Land-use classification of very high spatial resolution remote sensing (VHSR) imagery is one of the most challenging tasks in the field of remote sensing image processing. However, the land-use classification is hard to be addressed by the land-cover classification techniques, due to the complexity of the land-use scenes. Scene classification is considered to be one of the expected ways to address the land-use classification issue. The commonly used scene classification methods of VHSR imagery are all derived from the computer vision community that mainly deal with terrestrial image recognition. Differing from terrestrial images, VHSR images are taken by looking down with airborne and spaceborne sensors, which leads to the distinct light conditions and spatial configuration of land cover in VHSR imagery. Considering the distinct characteristics, two questions should be answered: (1) Which type or combination of information is suitable for the VHSR imagery scene classification? (2) Which scene classification algorithm is best for VHSR imagery? In this paper, an efficient spectral-structural bag-of-features scene classifier (SSBFC) is proposed to combine the spectral and structural information of VHSR imagery. SSBFC utilizes the first- and second-order statistics (the mean and standard deviation values, MeanStd) as the statistical spectral descriptor for the spectral information of the VHSR imagery, and uses dense scale-invariant feature transform (SIFT) as the structural feature descriptor. From the experimental results, the spectral information works better than the structural information, while the combination of the spectral and structural information is better than any single type of information. Taking the characteristic of the spatial configuration into consideration, SSBFC uses the whole image scene as the scope of the pooling operator, instead of the scope generated by a spatial pyramid (SP) commonly used in terrestrial image classification. The experimental

  17. Geostatistical modelling of the malaria risk in Mozambique: effect of the spatial resolution when using remotely-sensed imagery.

    PubMed

    Giardina, Federica; Franke, Jonas; Vounatsou, Penelope

    2015-01-01

    The study of malaria spatial epidemiology has benefited from recent advances in geographic information system and geostatistical modelling. Significant progress in earth observation technologies has led to the development of moderate, high and very high resolution imagery. Extensive literature exists on the relationship between malaria and environmental/climatic factors in different geographical areas, but few studies have linked human malaria parasitemia survey data with remote sensing-derived land cover/land use variables and very few have used Earth Observation products. Comparison among the different resolution products to model parasitemia has not yet been investigated. In this study, we probe a proximity measure to incorporate different land cover classes and assess the effect of the spatial resolution of remotely sensed land cover and elevation on malaria risk estimation in Mozambique after adjusting for other environmental factors at a fixed spatial resolution. We used data from the Demographic and Health survey carried out in 2011, which collected malaria parasitemia data on children from 0 to 5 years old, analysing them with a Bayesian geostatistical model. We compared the risk predicted using land cover and elevation at moderate resolution with the risk obtained employing the same variables at high resolution. We used elevation data at moderate and high resolution and the land cover layer from the Moderate Resolution Imaging Spectroradiometer as well as the one produced by MALAREO, a project covering part of Mozambique during 2010-2012 that was funded by the European Union's 7th Framework Program. Moreover, the number of infected children was predicted at different spatial resolutions using AFRIPOP population data and the enhanced population data generated by the MALAREO project for comparison of estimates. The Bayesian geostatistical model showed that the main determinants of malaria presence are precipitation and day temperature. However, the presence

  18. Environmental impact assessment of transportation projects: An analysis using an integrated GIS, remote sensing, and spatial modeling approach

    NASA Astrophysics Data System (ADS)

    El-Gafy, Mohamed Anwar

    Transportation projects will have impact on the environment. The general environmental pollution and damage caused by roads is closely associated with the level of economic activity. Although Environmental Impact Assessments (EIAs) are dependent on geo-spatial information in order to make an assessment, there are no rules per se how to conduct an environmental assessment. Also, the particular objective of each assessment is dictated case-by-case, based on what information and analyses are required. The conventional way of Environmental Impact Assessment (EIA) study is a time consuming process because it has large number of dependent and independent variables which have to be taken into account, which also have different consequences. With the emergence of satellite remote sensing technology and Geographic Information Systems (GIS), this research presents a new framework for the analysis phase of the Environmental Impact Assessment (EIA) for transportation projects based on the integration between remote sensing technology, geographic information systems, and spatial modeling. By integrating the merits of the map overlay method and the matrix method, the framework analyzes comprehensively the environmental vulnerability around the road and its impact on the environment. This framework is expected to: (1) improve the quality of the decision making process, (2) be applied both to urban and inter-urban projects, regardless of transport mode, and (3) present the data and make the appropriate analysis to support the decision of the decision-makers and allow them to present these data to the public hearings in a simple manner. Case studies, transportation projects in the State of Florida, were analyzed to illustrate the use of the decision support framework and demonstrate its capabilities. This cohesive and integrated system will facilitate rational decisions through cost effective coordination of environmental information and data management that can be tailored to

  19. Vascular microRNA-204 is remotely governed by the microbiome and impairs endothelium-dependent vasorelaxation by downregulating Sirtuin1.

    PubMed

    Vikram, Ajit; Kim, Young-Rae; Kumar, Santosh; Li, Qiuxia; Kassan, Modar; Jacobs, Julia S; Irani, Kaikobad

    2016-01-01

    Gut microbiota promotes atherosclerosis, and vascular endothelial dysfunction, signalled by impaired endothelium-dependent vasorelaxation, is an early marker of atherosclerosis. Here we show that vascular microRNA-204 (miR-204) expression is remotely regulated by the microbiome, and impairs endothelial function by targeting the Sirtuin1 lysine deacetylase (Sirt1). MiR-204 is downregulated, while Sirt1 is upregulated, in aortas of germ-free mice. Suppression of gut microbiome with broad-spectrum antibiotics decreases miR-204, increases Sirt1 and bioavailable vascular nitric oxide, and improves endothelium-dependent vasorelaxation in mouse aortas. Antibiotics curtail aortic miR-204 upregulation, and rescue decline of aortic Sirt1 and endothelium-dependent vasorelaxation, triggered by high-fat diet feeding. Improvement of endothelium-dependent vasorelaxation by antibiotics is lost in mice lacking endothelial Sirt1. Systemic antagonism of miR-204 rescues impaired endothelium-dependent vasorelaxation and vascular Sirt1, and decreases vascular inflammation induced by high-fat diet. These findings reveal a gut microbe-vascular microRNA-Sirtuin1 nexus that leads to endothelial dysfunction. PMID:27586459

  20. Early developmental bisphenol-A exposure sex-independently impairs spatial memory by remodeling hippocampal dendritic architecture and synaptic transmission in rats.

    PubMed

    Liu, Zhi-Hua; Ding, Jin-Jun; Yang, Qian-Qian; Song, Hua-Zeng; Chen, Xiang-Tao; Xu, Yi; Xiao, Gui-Ran; Wang, Hui-Li

    2016-01-01

    Bisphenol-A (BPA, 4, 4'-isopropylidene-2-diphenol), a synthetic xenoestrogen that widely used in the production of polycarbonate plastics, has been reported to impair hippocampal development and function. Our previous study has shown that BPA exposure impairs Sprague-Dawley (SD) male hippocampal dendritic spine outgrowth. In this study, the sex-effect of chronic BPA exposure on spatial memory in SD male and female rats and the related synaptic mechanism were further investigated. We found that chronic BPA exposure impaired spatial memory in both SD male and female rats, suggesting a dysfunction of hippocampus without gender-specific effect. Further investigation indicated that BPA exposure causes significant impairment of dendrite and spine structure, manifested as decreased dendritic complexity, dendritic spine density and percentage of mushroom shaped spines in hippocampal CA1 and dentate gyrus (DG) neurons. Furthermore, a significant reduction in Arc expression was detected upon BPA exposure. Strikingly, BPA exposure significantly increased the mIPSC amplitude without altering the mEPSC amplitude or frequency, accompanied by increased GABAARβ2/3 on postsynaptic membrane in cultured CA1 neurons. In summary, our study indicated that Arc, together with the increased surface GABAARβ2/3, contributed to BPA induced spatial memory deficits, providing a novel molecular basis for BPA achieved brain impairment. PMID:27578147

  1. Early developmental bisphenol-A exposure sex-independently impairs spatial memory by remodeling hippocampal dendritic architecture and synaptic transmission in rats

    PubMed Central

    Liu, Zhi-Hua; Ding, Jin-Jun; Yang, Qian-Qian; Song, Hua-Zeng; Chen, Xiang-Tao; Xu, Yi; Xiao, Gui-Ran; Wang, Hui-Li

    2016-01-01

    Bisphenol-A (BPA, 4, 4′-isopropylidene-2-diphenol), a synthetic xenoestrogen that widely used in the production of polycarbonate plastics, has been reported to impair hippocampal development and function. Our previous study has shown that BPA exposure impairs Sprague-Dawley (SD) male hippocampal dendritic spine outgrowth. In this study, the sex-effect of chronic BPA exposure on spatial memory in SD male and female rats and the related synaptic mechanism were further investigated. We found that chronic BPA exposure impaired spatial memory in both SD male and female rats, suggesting a dysfunction of hippocampus without gender-specific effect. Further investigation indicated that BPA exposure causes significant impairment of dendrite and spine structure, manifested as decreased dendritic complexity, dendritic spine density and percentage of mushroom shaped spines in hippocampal CA1 and dentate gyrus (DG) neurons. Furthermore, a significant reduction in Arc expression was detected upon BPA exposure. Strikingly, BPA exposure significantly increased the mIPSC amplitude without altering the mEPSC amplitude or frequency, accompanied by increased GABAARβ2/3 on postsynaptic membrane in cultured CA1 neurons. In summary, our study indicated that Arc, together with the increased surface GABAARβ2/3, contributed to BPA induced spatial memory deficits, providing a novel molecular basis for BPA achieved brain impairment. PMID:27578147

  2. Change detection based on deep feature representation and mapping transformation for multi-spatial-resolution remote sensing images

    NASA Astrophysics Data System (ADS)

    Zhang, Puzhao; Gong, Maoguo; Su, Linzhi; Liu, Jia; Li, Zhizhou

    2016-06-01

    Multi-spatial-resolution change detection is a newly proposed issue and it is of great significance in remote sensing, environmental and land use monitoring, etc. Though multi-spatial-resolution image-pair are two kinds of representations of the same reality, they are often incommensurable superficially due to their different modalities and properties. In this paper, we present a novel multi-spatial-resolution change detection framework, which incorporates deep-architecture-based unsupervised feature learning and mapping-based feature change analysis. Firstly, we transform multi-resolution image-pair into the same pixel-resolution through co-registration, followed by details recovery, which is designed to remedy the spatial details lost in the registration. Secondly, the denoising autoencoder is stacked to learn local and high-level representation/feature from the local neighborhood of the given pixel, in an unsupervised fashion. Thirdly, motivated by the fact that multi-resolution image-pair share the same reality in the unchanged regions, we try to explore the inner relationships between them by building a mapping neural network. And it can be used to learn a mapping function based on the most-unlikely-changed feature-pairs, which are selected from all the feature-pairs via a coarse initial change map generated in advance. The learned mapping function can bridge the different representations and highlight changes. Finally, we can build a robust and contractive change map through feature similarity analysis, and the change detection result is obtained through the segmentation of the final change map. Experiments are carried out on four real datasets, and the results confirmed the effectiveness and superiority of the proposed method.

  3. Functional neuroanatomy of remote episodic, semantic and spatial memory: a unified account based on multiple trace theory

    PubMed Central

    Moscovitch, Morris; Rosenbaum, R Shayna; Gilboa, Asaf; Addis, Donna Rose; Westmacott, Robyn; Grady, Cheryl; McAndrews, Mary Pat; Levine, Brian; Black, Sandra; Winocur, Gordon; Nadel, Lynn

    2005-01-01

    We review lesion and neuroimaging evidence on the role of the hippocampus, and other structures, in retention and retrieval of recent and remote memories. We examine episodic, semantic and spatial memory, and show that important distinctions exist among different types of these memories and the structures that mediate them. We argue that retention and retrieval of detailed, vivid autobiographical memories depend on the hippocampal system no matter how long ago they were acquired. Semantic memories, on the other hand, benefit from hippocampal contribution for some time before they can be retrieved independently of the hippocampus. Even semantic memories, however, can have episodic elements associated with them that continue to depend on the hippocampus. Likewise, we distinguish between experientially detailed spatial memories (akin to episodic memory) and more schematic memories (akin to semantic memory) that are sufficient for navigation but not for re-experiencing the environment in which they were acquired. Like their episodic and semantic counterparts, the former type of spatial memory is dependent on the hippocampus no matter how long ago it was acquired, whereas the latter can survive independently of the hippocampus and is represented in extra-hippocampal structures. In short, the evidence reviewed suggests strongly that the function of the hippocampus (and possibly that of related limbic structures) is to help encode, retain, and retrieve experiences, no matter how long ago the events comprising the experience occurred, and no matter whether the memories are episodic or spatial. We conclude that the evidence favours a multiple trace theory (MTT) of memory over two other models: (1) traditional consolidation models which posit that the hippocampus is a time-limited memory structure for all forms of memory; and (2) versions of cognitive map theory which posit that the hippocampus is needed for representing all forms of allocentric space in memory. PMID

  4. Spatial Symmetry Breaking in the Belousov-Zhabotinsky Reaction with Light-Induced Remote Communication

    SciTech Connect

    Hildebrand, M.; Skodt, H.; Showalter, K.

    2001-08-20

    Domains containing spiral waves form on a stationary background in a photosensitive Belousov-Zhabotinsky reaction with light-induced alternating nonlocal feedback. Complex behavior of colliding and splitting wave fragments is found with feedback radii comparable to the spiral wavelength. A linear stability analysis of the uniform stationary states in an Oregonator model reveals a spatial symmetry breaking instability. Numerical simulations show behavior in agreement with that found experimentally and also predict a variety of other new patterns.

  5. Prenatal exposure to noise stress: anxiety, impaired spatial memory, and deteriorated hippocampal plasticity in postnatal life.

    PubMed

    Barzegar, Marzieh; Sajjadi, Fatemeh Sadat; Talaei, Sayyed Alireza; Hamidi, Gholamali; Salami, Mahmoud

    2015-02-01

    Sound pollution is known as an annoying phenomenon in modern life. Especially, development of organisms during fetal life is more sensitive to environmental tensions. To address a link between the behavioral and electrophysiological aspects of brain function with action of hypothalamus-pituitary-adrenal (HPA) axis in stressed animals, this study was carried out on the male Wistar rats prenatally exposed to sound stress. Groups of pregnant rats were exposed to noise stress for 1, 2, and 4 hour(s). The degree of anxiety and the spatial memory were evaluated by elevated plus maze and Morris water maze, respectively. Basic synaptic activity and long-term potentiation (LTP) induction were assessed in the CA3-CA1 pathway of hippocampus. The serum level of corticosterone was measured in the pregnant mothers and the offspring. The behavioral experiments appeared that the stressed animals performed considerably weaker than the control rats. The prenatal stress negatively affected the basic synaptic responses and led to a lower level of LTP. The pregnant animals showed an increased serum corticosterone in comparison with the nonpregnant females. Also the offspring exposed to the noise stress had a more elevated level of corticosterone than the control rats. Our findings indicate that the corticosterone concentration changes markedly coincides the results of behavioral and electrophysiological experiments. We conclude that, similar to other environmental stresses, the sound stress during fetal life efficiently disturbs both cognitive abilities and synaptic activities. The changes in action of HPA axis may contribute to problems of the brain function in the prenatally stress exposed animals. PMID:25214446

  6. Spatial release of cognitive load measured in a dual-task paradigm in normal-hearing and hearing-impaired listeners.

    PubMed

    Xia, Jing; Nooraei, Nazanin; Kalluri, Sridhar; Edwards, Brent

    2015-04-01

    This study investigated whether spatial separation between talkers helps reduce cognitive processing load, and how hearing impairment interacts with the cognitive load of individuals listening in multi-talker environments. A dual-task paradigm was used in which performance on a secondary task (visual tracking) served as a measure of the cognitive load imposed by a speech recognition task. Visual tracking performance was measured under four conditions in which the target and the interferers were distinguished by (1) gender and spatial location, (2) gender only, (3) spatial location only, and (4) neither gender nor spatial location. Results showed that when gender cues were available, a 15° spatial separation between talkers reduced the cognitive load of listening even though it did not provide further improvement in speech recognition (Experiment I). Compared to normal-hearing listeners, large individual variability in spatial release of cognitive load was observed among hearing-impaired listeners. Cognitive load was lower when talkers were spatially separated by 60° than when talkers were of different genders, even though speech recognition was comparable in these two conditions (Experiment II). These results suggest that a measure of cognitive load might provide valuable insight into the benefit of spatial cues in multi-talker environments. PMID:25920841

  7. Integration of remotely sensed and model data to provide the spatial information basis for sustainable landuse

    NASA Astrophysics Data System (ADS)

    Backhaus, R.; Braun, G.

    Sustainable development is by now generally accepted as the paramount objective of environmental policy. Environmental applications of Earth observation, on the other hand, have been successfully demonstrated over a wide range of monitoring activities, mostly with the aim of describing the spatial distribution and time course of geophysical parameters and land surface structures. With landuse structures being of major influence on the sustainability of terrestrial ecosystems, and being also a highly suitable object of Earth observation, it is still an open question, however, in which way Earth observation data can be processed and integrated to provide an approximate indicator of sustainability. Based on an ecological sustainability model developed by Ripl and his co-workers at Berlin Technical University, this question was investigated in the framework of the joint project "Development of a Land-Water-Management Concept to Decrease Matter Losses to Open Waters" (Stör project), which was funded by the German Federal Ministry of Research and Technology. Present results may be summarized as follows: 1. Apart from hydrological point measurements, there are several spatial parameters which are of indicative value as to sustainability, especially the spatio-temporal distribution of biomass, surface temperature, and precipitation. 2. To provide the spatial information basis for enhanced efficiency of immediate measures such as reforestation, agricultural extension etc., a global information system (GIS) concept was developed and demonstrated which is based on a landuse/vegetation classification derived from Landsat TM data, a digital evaluation mode (DEM) and a relief dependent water distribution model (WDM). Further implications such as the organisation of information systems which are to serve sustainability strategies are discussed.

  8. Agro-hydrology and multi temporal high resolution remote sensing: toward an explicit spatial processes calibration

    NASA Astrophysics Data System (ADS)

    Ferrant, S.; Gascoin, S.; Veloso, A.; Salmon-Monviola, J.; Claverie, M.; Rivalland, V.; Dedieu, G.; Demarez, V.; Ceschia, E.; Probst, J.-L.; Durand, P.; Bustillo, V.

    2014-07-01

    The recent and forthcoming availability of high resolution satellite image series offers new opportunities in agro-hydrological research and modeling. We investigated the perspective offered by improving the crop growth dynamic simulation using the distributed agro-hydrological model, Topography based Nitrogen transfer and Transformation (TNT2), using LAI map series derived from 105 Formosat-2 (F2) images during the period 2006-2010. The TNT2 model (Beaujouan et al., 2002), calibrated with discharge and in-stream nitrate fluxes for the period 1985-2001, was tested on the 2006-2010 dataset (climate, land use, agricultural practices, discharge and nitrate fluxes at the outlet). A priori agricultural practices obtained from an extensive field survey such as seeding date, crop cultivar, and fertilizer amount were used as input variables. Continuous values of LAI as a function of cumulative daily temperature were obtained at the crop field level by fitting a double logistic equation against discrete satellite-derived LAI. Model predictions of LAI dynamics with a priori input parameters showed an temporal shift with observed LAI profiles irregularly distributed in space (between field crops) and time (between years). By re-setting seeding date at the crop field level, we proposed an optimization method to minimize efficiently this temporal shift and better fit the crop growth against the spatial observations as well as crop production. This optimization of simulated LAI has a negligible impact on water budget at the catchment scale (1 mm yr-1 in average) but a noticeable impact on in-stream nitrogen fluxes (around 12%) which is of interest considering nitrate stream contamination issues and TNT2 model objectives. This study demonstrates the contribution of forthcoming high spatial and temporal resolution products of Sentinel-2 satellite mission in improving agro-hydrological modeling by constraining the spatial representation of crop productivity.

  9. a Temporal and Spatial Analysis of Urban Heat Island in Basin City Utilizing Remote Sensing Techniques

    NASA Astrophysics Data System (ADS)

    Chang, Hsiao-Tung

    2016-06-01

    Urban Heat Island (UHI) has been becoming a key factor in deteriorating the urban ecological environment. Spatial-temporal analysis on its prototype of basin city's UHI and quantitatively evaluating effect from rapid urbanization will provide theoretical foundation for relieving UHI effect. Based on Landsat 8, ETM+ and TM images of Taipei basin areas from 1900 to 2015, this article has retrieved the land surface temperature (LST) at summer solstice of each year, and then analysed spatial-temporal pattern and evolution characters of UHI in Taipei basin in this decade. The results showed that the expansion built district, UHI area constantly expanded from centre city to the suburb areas. The prototype of UHI in Taipei basin that showed in addition to higher temperatures in the centre city also were relatively high temperatures gathered boundaries surrounded by foot of mountains side. It calls "sinking heat island". From 1900 to 2000, the higher UHI areas were different land use type change had obvious difference by public infrastructure works. And then, in next 15 years till 2015, building density of urban area has been increasing gradually. It has the trend that UHI flooding raises follow urban land use density. Hot spot of UHI in Taipei basin also has the same characteristics. The results suggest that anthropogenic heat release probably plays a significant role in the UHI effect, and must be considered in urban planning adaptation strategies.

  10. Estimating noise levels of remotely sensed measurements from satellites using spatial structure analysis

    NASA Technical Reports Server (NTRS)

    Hillger, Donald W.; Vonder Haar, Thomas H.

    1988-01-01

    A technique is presented whereby the noise level of satellite measurements of the atmosphere and earth can be estimated. The technique analyzes a spatial array of data measured by a satellite instrument. A minimum of about 200 satellite measurements is required, preferably in a regular pattern. Statistical structure analysis is used to describe a combination of the mean gradient and noise in the data. The noise level is then estimated by separating out the gradient information and leaving only the noise. Results are presented for four satellite sounding instruments, and effective blackbody or brightness temperature noise levels were compared to prelaunch specifications or inflight calibrations for each instrument. Comparisons showed that in the absence of cloud-contaminated measurements (in the case of infrared data) and away from the highly variable ground surface, the noise level of various satellite instruments can be obtained without the need for calibration data. The noise levels imply how much spatial averaging is possible, without smearing the detected geophysical gradient, and how much is necessary, to meet the absolute signal accuracy requirements for the intended use of the satellite measurements.

  11. Metamaterials for Remote Generation of Spatially Controllable Two Dimensional Array of Microplasma

    PubMed Central

    Singh, Pramod K.; Hopwood, Jeffrey; Sonkusale, Sameer

    2014-01-01

    Since the initial demonstration of negative refraction and cloaking using metamaterials, there has been enormous interest and progress in making practical devices based on metamaterials such as electrically small antennas, absorbers, modulators, detectors etc that span over a wide range of electromagnetic spectrum covering microwave, terahertz, infrared (IR) and optical wavelengths. We present metamaterial as an active substrate where each unit cell serves as an element for generation of plasma, the fourth state of matter. Sub-wavelength localization of incident electromagnetic wave energy, one of the most interesting properties of metamaterials is employed here for generating high electric field to ignite and sustain microscale plasmas. Frequency selective nature of the metamaterial unit cells make it possible to generate spatially localized microplasma in a large array using multiple resonators. A dual resonator topology is shown for the demonstration. Since microwave energy couples to the metamaterial through free space, the proposed approach is naturally wireless. Such spatially controllable microplasma arrays provide a fundamentally new material system for future investigations in novel applications, e.g. nonlinear metamaterials. PMID:25098976

  12. Metamaterials for remote generation of spatially controllable two dimensional array of microplasma.

    PubMed

    Singh, Pramod K; Hopwood, Jeffrey; Sonkusale, Sameer

    2014-01-01

    Since the initial demonstration of negative refraction and cloaking using metamaterials, there has been enormous interest and progress in making practical devices based on metamaterials such as electrically small antennas, absorbers, modulators, detectors etc that span over a wide range of electromagnetic spectrum covering microwave, terahertz, infrared (IR) and optical wavelengths. We present metamaterial as an active substrate where each unit cell serves as an element for generation of plasma, the fourth state of matter. Sub-wavelength localization of incident electromagnetic wave energy, one of the most interesting properties of metamaterials is employed here for generating high electric field to ignite and sustain microscale plasmas. Frequency selective nature of the metamaterial unit cells make it possible to generate spatially localized microplasma in a large array using multiple resonators. A dual resonator topology is shown for the demonstration. Since microwave energy couples to the metamaterial through free space, the proposed approach is naturally wireless. Such spatially controllable microplasma arrays provide a fundamentally new material system for future investigations in novel applications, e.g. nonlinear metamaterials. PMID:25098976

  13. Spatial Estimation of Sub-Hour Global Horizontal Irradiance Based on Official Observations and Remote Sensors

    PubMed Central

    Gutierrez-Corea, Federico-Vladimir; Manso-Callejo, Miguel-Angel; Moreno-Regidor, María-Pilar; Velasco-Gómez, Jesús

    2014-01-01

    This study was motivated by the need to improve densification of Global Horizontal Irradiance (GHI) observations, increasing the number of surface weather stations that observe it, using sensors with a sub-hour periodicity and examining the methods of spatial GHI estimation (by interpolation) with that periodicity in other locations. The aim of the present research project is to analyze the goodness of 15-minute GHI spatial estimations for five methods in the territory of Spain (three geo-statistical interpolation methods, one deterministic method and the HelioSat2 method, which is based on satellite images). The research concludes that, when the work area has adequate station density, the best method for estimating GHI every 15 min is Regression Kriging interpolation using GHI estimated from satellite images as one of the input variables. On the contrary, when station density is low, the best method is estimating GHI directly from satellite images. A comparison between the GHI observed by volunteer stations and the estimation model applied concludes that 67% of the volunteer stations analyzed present values within the margin of error (average of ±2 standard deviations). PMID:24732102

  14. Loss of EphA4 impairs short-term spatial recognition memory performance and locomotor habituation.

    PubMed

    Willi, R; Winter, C; Wieske, F; Kempf, A; Yee, B K; Schwab, M E; Singer, P

    2012-11-01

    EphA4 receptor (EphA4) tyrosine kinase is an important regulator of central nervous system development and synaptic plasticity in the mature brain, but its relevance to the control of normal behavior remains largely unexplored. This study is the first attempt to obtain a behavioral profile of constitutive homozygous and heterozygous EphA4 knockout mice. A deficit in locomotor habituation in the open field, impairment in spatial recognition in the Y-maze and reduced probability of spatial spontaneous alternation in the T-maze were identified in homozygous EphA4(-/-) mice, while heterozygo us EphA4(+/-) mice appeared normal on these tests in comparison with wild-type (WT) controls. The multiple phenotypes observed in EphA4(-/-) mice might stem from an underlying deficit in habituation learning, reflecting an elementary form of nonassociative learning that is in contrast to Pavlovian associative learning, which appeared unaffected by EphA4 disruption. A deficit in motor coordination on the accelerating rotarod was also demonstrated only in EphA4(-/-) mice--a finding in keeping with the presence of abnormal gait in EphA4(-/-) mice--although they were able to improve performance over training. There was no evidence for substantial changes in major neurochemical markers in various brain regions rich in EphA4 as shown by post-mortem analysis. This excludes the possibility of major neurochemical compensation in the brain of EphA4(-/-) mice. In summary, we have demonstrated for the first time the behavioral significance of EphA4 disruption, supporting further investigation of EphA4 as a possible target for behavioral interventions where habituation deficits are prominent. PMID:22938696

  15. Study of vegetation impact on the ground surface temperature using remote sensing data with different spatial resolution

    NASA Astrophysics Data System (ADS)

    Dvornikov, Yury; Heim, Birgit; Leibman, Marina

    2013-04-01

    Permafrost mapping and modeling is based on the understanding of the main controls affecting permafrost parameters: ground temperature, active-layer thickness, cryogenic processes. In the Tundra zone, remote sensing can provide necessary information on spatial distribution of surficial parameters represented by vegetation type and coverage. In this work we will consider shrub complexes, as far as they serve as an entrapment for snow and consequently affect the active layer depth. A case study was undertaken at central Yamal at the research station Vaskiny Dachi. In summer 2011 a 1.5 km long transect crossing main geomorphologic units of central Yamal was established and subject to multipurpose field study. Detailed description of vegetation and numeric parameters characterizing tundra complexes was followed by active-layer measurements. The main optical satellite data base is a high-spatial resolution GeoEye-1 acquisition with 0.5 m ground sampling distance acquired at the 15th August in 2009 (NGA license, University Alaska Fairbanks, NASA LCLUC Yamal). Spectral analyses were performed to extract surface class - shrub-dominant communities. Spectral discrimination of surface waters was done using a threshold value in the near infrared band 4. Various spectral analyses were tested to separate shrubs-dominated areas. Processed were 4 Principal Component (PC) (Schowengerdt, 2007) bands, including masking of surface waters. The lower PC bands contain the subordinate information that can often not be extracted using standard classification methods. PC bands 2 and 3 were interpreted to contain information on 'greenness' and 'moisture and structure', respectively. At this stage, the shrubs were manually digitized guided by the structure information in PC band 3. The communities sorted out in vector format were used for the following analysis. For the analysis of the shrub impact on permafrost, interpretation results were compared with a map of the surface temperature and

  16. Agricultural drought assessment at spatial and temporal scales using remotely sensed data

    NASA Astrophysics Data System (ADS)

    Shin, Yongchul; Park, Kyungwon; Rhee, Jinyoung; Yoon, Sunkwon

    2016-04-01

    We estimated soil moisture dynamics in the root zone based on a soil moisture data assimilation scheme using remotely sensed (RS) data. The data assimilation scheme estimated the soil hydraulic and root parameters from MODerate resolution Imaging Spectroradiometer (MODIS) data. Then, root zone soil moisture was estimated at spatio-temporal scales based on the estimated soil/root parameters and weather forcings. We validated our approach at the Little Washita(LW13) in Oklahoma and Chungmi-cheon/Seolma-cheon sites. The estimated water retention curves identified well with the measurements at the LW 13 site. Also, the estimated root zone soil moisture dynamics showed an agreement with the Time Domain Reflectrometry(TDR)-based measured data. Furthermore, we tested this approach at ungauged regions (Seolma Cheon-SC and Chungmi Cheon-CC) South Korea indicating that the soil/root parameters at the pixel where the SC site is located were derived from the calibrated MODIS-based(the CC site) soil moisture values. Then, the estimated root zone soil moisture values were validated with the measured data at the SC site. Although the model outputs were slightly overestimated compared to the measured data, these results showed the applicability of this proposed approach in application to ungauged regions. Thus, our proposed approach can be helpful to evaluate root zone soil moisture at spatio-temporal scales across South Korea. Acknowledgement This research was partially supported by Kyungpook National University Research Fund (2015) and a grant (14AWMP-B079364-01) from Water Management Research Program funded by Ministry of Land, Infrastructure and Transport of Korean government.

  17. Developmental D-methamphetamine treatment selectively induces spatial navigation impairments in reference memory in the Morris water maze while sparing working memory.

    PubMed

    Williams, Michael T; Morford, LaRonda L; Wood, Sandra L; Wallace, Tanya L; Fukumura, Masao; Broening, Harry W; Vorhees, Charles V

    2003-06-01

    In previous studies, we have shown that P11-20 treatment with D-methamphetamine (MA) (10 mg/kg x 4/day at 2-h intervals) induces impairments in spatial learning and memory in the Morris water maze after the offspring reach adulthood. Using a split-litter, multiple dose, design (0, 5, 10, and 15 mg/kg MA administered s.c. 4/day at 2-h intervals), the spatial learning effect was further explored with a multiple shifted platform (reversal), reference memory-based procedure and a working memory procedure. Prior to spatial learning, animals were first tested for swimming ability (in a straight swimming channel), sequential learning (in the Cincinnati multiple-T water maze), and proximal cue learning (in the Morris water maze). Rats were then assessed in the hidden platform, reference memory-based spatial version of the Morris maze for acquisition and on five subsequent phases in which the platform was moved to new locations. After the reference memory-based, fixed platform position learning phases, animals were tested in the trial-dependent, matching-to-sample, working memory version of the Morris maze. No group differences were found in straight channel, sequential maze, or cued Morris maze performance. By contrast, all MA groups were impaired in spatial learning during acquisition, multiple shift, and shifted with a reduced platform phases of reference memory-based learning. In addition, MA animals were impaired on memory (probe) trials during the acquisition and shifted with a reduced platform phases of learning. No effects on trial-dependent, matching-to-sample, working memory were found. The findings demonstrate that neonatal treatment with MA induces a selective impairment of reference memory-based spatial learning while sparing sequential, cued, and working memory-based learning. PMID:12645039

  18. Synaptic plasticity and spatial working memory are impaired in the CD mouse model of Williams-Beuren syndrome.

    PubMed

    Borralleras, Cristina; Mato, Susana; Amédée, Thierry; Matute, Carlos; Mulle, Christophe; Pérez-Jurado, Luis A; Campuzano, Victoria

    2016-01-01

    Mice heterozygous for a complete deletion (CD) equivalent to the most common deletion found in individuals with Williams-Beuren syndrome (WBS) recapitulate relevant features of the neurocognitive phenotype, such as hypersociability, along with some neuroanatomical alterations in specific brain areas. However, the pathophysiological mechanisms underlying these phenotypes still remain largely unknown. We have studied the synaptic function and cognition in CD mice using hippocampal slices and a behavioral test sensitive to hippocampal function. We have found that long-term potentiation (LTP) elicited by theta burst stimulation (TBS) was significantly impaired in hippocampal field CA1 of CD animals. This deficit might be associated with the observed alterations in spatial working memory. However, we did not detect changes in presynaptic function, LTP induction mechanisms or AMPA and NMDA receptor function. Reduced levels of Brain-derived neurotrophic factor (BDNF) were present in the CA1-CA3 hippocampal region of CD mice, which could account for LTP deficits in these mice. Taken together, these results suggest a defect of CA1 synapses in CD mice to sustain synaptic strength after stimulation. These data represent the first description of synaptic functional deficits in CD mice and further highlights the utility of the CD model to study the mechanisms underlying the WBS neurocognitive profile. PMID:27485321

  19. Dentate gyrus-specific knockdown of adult neurogenesis impairs spatial and object recognition memory in adult rats

    PubMed Central

    Jessberger, Sebastian; Clark, Robert E.; Broadbent, Nicola J.; Clemenson, Gregory D.; Consiglio, Antonella; Lie, D. Chichung; Squire, Larry R.; Gage, Fred H.

    2009-01-01

    New granule cells are born throughout life in the dentate gyrus of the hippocampal formation. Given the fundamental role of the hippocampus in processes underlying certain forms of learning and memory, it has been speculated that newborn granule cells contribute to cognition. However, previous strategies aiming to causally link newborn neurons with hippocampal function used ablation strategies that were not exclusive to the hippocampus or that were associated with substantial side effects, such as inflammation. We here used a lentiviral approach to specifically block neurogenesis in the dentate gyrus of adult male rats by inhibiting WNT signaling, which is critically involved in the generation of newborn neurons, using a dominant-negative WNT (dnWNT). We found a level-dependent effect of adult neurogenesis on the long-term retention of spatial memory in the water maze task, as rats with substantially reduced levels of newborn neurons showed less preference for the target zone in probe trials >2 wk after acquisition compared with control rats. Furthermore, animals with strongly reduced levels of neurogenesis were impaired in a hippocampus-dependent object recognition task. Social transmission of food preference, a behavioral test that also depends on hippocampal function, was not affected by knockdown of neurogenesis. Here we identified a role for newborn neurons in distinct aspects of hippocampal function that will set the ground to further elucidate, using experimental and computational strategies, the mechanism by which newborn neurons contribute to behavior. PMID:19181621

  20. CB2 Cannabinoid Receptor Knockout in Mice Impairs Contextual Long-Term Memory and Enhances Spatial Working Memory

    PubMed Central

    Li, Yong; Kim, Jimok

    2016-01-01

    Neurocognitive effects of cannabinoids have been extensively studied with a focus on CB1 cannabinoid receptors because CB1 receptors have been considered the major cannabinoid receptor in the nervous system. However, recent discoveries of CB2 cannabinoid receptors in the brain demand accurate determination of whether and how CB2 receptors are involved in the cognitive effects of cannabinoids. CB2 cannabinoid receptors are primarily involved in immune functions, but also implicated in psychiatric disorders such as schizophrenia and depression. Here, we examined the effects of CB2 receptor knockout in mice on memory to determine the roles of CB2 receptors in modulating cognitive function. Behavioral assays revealed that hippocampus-dependent, long-term contextual fear memory was impaired whereas hippocampus-independent, cued fear memory was normal in CB2 receptor knockout mice. These mice also displayed enhanced spatial working memory when tested in a Y-maze. Motor activity and anxiety of CB2 receptor knockout mice were intact when assessed in an open field arena and an elevated zero maze. In contrast to the knockout of CB2 receptors, acute blockade of CB2 receptors by AM603 in C57BL/6J mice had no effect on memory, motor activity, or anxiety. Our results suggest that CB2 cannabinoid receptors play diverse roles in regulating memory depending on memory types and/or brain areas. PMID:26819779

  1. DCP-LA neutralizes mutant amyloid beta peptide-induced impairment of long-term potentiation and spatial learning.

    PubMed

    Nagata, Tetsu; Tomiyama, Takami; Tominaga, Takemi; Mori, Hiroshi; Yaguchi, Takahiro; Nishizaki, Tomoyuki

    2010-01-01

    Long-term potentiation (LTP) was monitored from the CA1 region of the intact rat hippocampus by delivering high frequency stimulation (HFS) to the Schaffer collateral commissural pathway. Intraventricular injection with mutant amyloid beta(1-42) peptide lacking glutamate-22 (Abeta(1-42)E22Delta), favoring oligomerization, 10 min prior to HFS, inhibited expression of LTP, with the potency more than wild-type amyloid beta(1-42) peptide. Intraperitoneal injection with the linoleic acid derivative 8-[2-(2-pentyl-cyclopropylmethyl)-cyclopropyl]-octanoic acid (DCP-LA) 70 min prior to HFS neutralized mutant Abeta(1-42)E22Delta peptide-induced LTP inhibition. In the water maze test, continuous intraventricular injection with mutant Abeta(1-42)E22Delta peptide for 14 days prolonged the acquisition latency as compared with that for control, with the potency similar to wild-type Abeta(1-42) peptide, and intraperitoneal injection with DCP-LA shortened the prolonged latency to control levels. The results of the present study indicate that DCP-LA neutralizes mutant Abeta(1-42)E22Delta peptide-induced impairment of LTP and spatial learning. PMID:19716848

  2. Adult-onset hyperthyroidism impairs spatial learning: possible involvement of mitogen-activated protein kinase signaling pathways.

    PubMed

    Bitiktaş, Soner; Kandemir, Başak; Tan, Burak; Kavraal, Şehrazat; Liman, Narin; Dursun, Nurcan; Dönmez-Altuntaş, Hamiyet; Aksan-Kurnaz, Işil; Suer, Cem

    2016-08-01

    Given evidence that mitogen-activated protein kinase (MAPK) activation is part of the nongenomic actions of thyroid hormones, we investigated the possible consequences of hyperthyroidism for the cognitive functioning of adult rats. Young adult rats were treated with L-thyroxine or saline. Twenty rats in each group were exposed to Morris water maze testing, measuring their performance in a hidden-platform spatial task. In a separate set of rats not exposed to Morris water maze testing (untrained rats), the expression and phosphorylated levels of p38-MAPK and of its two downstream effectors, Elk-1 and cAMP response element-binding protein, were evaluated using quantitative reverse transcriptase-PCR and western blotting. Rats with hyperthyroidism showed delayed acquisition of learning compared with their wild-type counterparts, as shown by increased escape latencies and distance moved on the last two trials of daily training in the water maze. The hyperthyroid rats, however, showed no difference during probe trials. Western blot analyses of the hippocampus showed that hyperthyroidism increased phosphorylated p38-MAPK levels in untrained rats. Although our study is correlative in nature and does not exclude the contribution of other molecular targets, our findings suggest that the observed impairments in acquisition during actual learning in rats with hyperthyroidism may result from the increased phosphorylation of p38-MAPK. PMID:27258653

  3. A spatial-temporal Hopfield neural network approach for super-resolution land cover mapping with multi-temporal different resolution remotely sensed images

    NASA Astrophysics Data System (ADS)

    Li, Xiaodong; Ling, Feng; Du, Yun; Feng, Qi; Zhang, Yihang

    2014-07-01

    The mixed pixel problem affects the extraction of land cover information from remotely sensed images. Super-resolution mapping (SRM) can produce land cover maps with a finer spatial resolution than the remotely sensed images, and reduce the mixed pixel problem to some extent. Traditional SRMs solely adopt a single coarse-resolution image as input. Uncertainty always exists in resultant fine-resolution land cover maps, due to the lack of information about detailed land cover spatial patterns. The development of remote sensing technology has enabled the storage of a great amount of fine spatial resolution remotely sensed images. These data can provide fine-resolution land cover spatial information and are promising in reducing the SRM uncertainty. This paper presents a spatial-temporal Hopfield neural network (STHNN) based SRM, by employing both a current coarse-resolution image and a previous fine-resolution land cover map as input. STHNN considers the spatial information, as well as the temporal information of sub-pixel pairs by distinguishing the unchanged, decreased and increased land cover fractions in each coarse-resolution pixel, and uses different rules in labeling these sub-pixels. The proposed STHNN method was tested using synthetic images with different class fraction errors and real Landsat images, by comparing with pixel-based classification method and several popular SRM methods including pixel-swapping algorithm, Hopfield neural network based method and sub-pixel land cover change mapping method. Results show that STHNN outperforms pixel-based classification method, pixel-swapping algorithm and Hopfield neural network based model in most cases. The weight parameters of different STHNN spatial constraints, temporal constraints and fraction constraint have important functions in the STHNN performance. The heterogeneity degree of the previous map and the fraction images errors affect the STHNN accuracy, and can be served as guidances of selecting the

  4. Local rank-based spatial information for improvement of remote sensing hyperspectral imaging resolution.

    PubMed

    Zhang, Xin; Juan, Anna de; Tauler, Romà

    2016-01-01

    This paper shows the effect of using local rank and selectivity constraints based on spatial information of spectroscopic images to increase the performance of Multivariate Curve Resolution (MCR) methods and to decrease the ambiguity of final results. Fixed Size Image Window-Evolving Factor Analysis (FSIW-EFA) is applied to discover which pixels are more suitable for the application of local rank constraints. An automated method to help in setting appropriate threshold values for the application of FSIW-EFA, based on global and local use of Singular Value Decomposition (SVD) is proposed. Additional use of correlation coefficients between selected reference spectra and pixel spectra of the image is shown to provide an alternative way for the application of the selectivity constraint in spectroscopic images for the first time. This alternative method resulted to be satisfactory when pure pixels exist. PMID:26695226

  5. Retrieving Crops Green Area Index from High Temporal and Spatial Resolution Remote Sensing Data

    NASA Astrophysics Data System (ADS)

    Veloso, A.; Demarez, V.; Ceschia, E.

    2012-04-01

    This paper aims at firstly evaluating the correspondence between Normalized Difference Vegetation Index (NDVI) products from Formosat-2 (F2) and SPOT sensors and then to perform a comparative analysis of two methods for retrieving Green Area Index from high spatial and temporal resolution satellite data (F2 and SPOT). For this purpose, an empirical approach using NDVI plus field data and a Neural Network approach using the PROSAIL model are compared over four different crops: maize, soybean, sunflower and wheat. The performance of both methods were evaluated and compared with in-situ direct (destructive) and indirect (hemispherical photos) measurements. Results suggest better performances for the empirical approach (R², RMSE). Still the physically-based method leads to good results (R², RMSE). The latter seems to be more promising due to its portability and independence from field measurements. Therefore new perspectives to improve this approach are being envisaged.

  6. Using Satellite Remote Sensing Data in a Spatially Explicit Price Model

    NASA Technical Reports Server (NTRS)

    Brown, Molly E.; Pinzon, Jorge E.; Prince, Stephen D.

    2007-01-01

    Famine early warning organizations use data from multiple disciplines to assess food insecurity of communities and regions in less-developed parts of the World. In this paper we integrate several indicators that are available to enhance the information for preparation for and responses to food security emergencies. The assessment uses a price model based on the relationship between the suitability of the growing season and market prices for coarse grain. The model is then used to create spatially continuous maps of millet prices. The model is applied to the dry central and northern areas of West Africa, using satellite-derived vegetation indices for the entire region. By coupling the model with vegetation data estimated for one to four months into the future, maps are created of a leading indicator of potential price movements. It is anticipated that these maps can be used to enable early warning of famine and for planning appropriate responses.

  7. Spatial and temporal patterns of burned area over Brazilian Cerrado from 2005 to 2015 using remote sensing data

    NASA Astrophysics Data System (ADS)

    Libonati, Renata; DaCamara, Carlos; Setzer, Alberto

    2016-04-01

    Although Cerrado is a fire-dependent biome, current agriculture practices have significantly modified the native fire regime. Moreover, over the last decades, climate conditions, such as intensive droughts, have contributed to enhance the effects of anthropogenic activities, and consequently fire, over the region. For instance, during the 2010 extreme drought there was an increase of 100% in the number of fire pixels detected by just one polar orbiting satellite (information online at http://www.cptec.inpe.br/queimadas). A better characterization of spatial and temporal fire patterns over Cerrado is therefore crucial to uncover both climate and anthropogenic influences in this ecosystem. Additionally, information about the extent, location and time of burned areas (BA) over Cerrado is especially useful to a wide range of users, from government agencies, research groups and ecologists, to fire managers and NGOs. Instruments on-board satellites are the only available operational means to collect BA data at appropriated spatial and temporal scales and in a cost-effective way. Several global BA products derived from remote sensed information have been developed over the last years using a variety of techniques based on different spatial, spectral and temporal resolutions. Although presenting similar inter-annual variability, there are marked differences among the products both in magnitude and location of the area burnt. The development of regional algorithms which take into account local characteristics such as vegetation type, soil and climate is therefore an added value to the existing information. We present a monthly BA product (AQM) for Brazil based on information from MODIS 1km. The algorithm was specifically designed for ecosystems in Brazil and the procedure represents the first initiative of an automated method for BA monitoring using remote sensing information in the country. The product relies on an algorithm that takes advantage of the ability of MIR

  8. Multi-objective calibration of a hydrologic model using spatially distributed remotely sensed/in-situ soil moisture

    NASA Astrophysics Data System (ADS)

    Rajib, Mohammad Adnan; Merwade, Venkatesh; Yu, Zhiqiang

    2016-05-01

    The objective of this study is to evaluate the relative potential of spatially distributed surface and root zone soil moisture estimates in calibration of Soil and Water Assessment Tool (SWAT) toward improving its hydrologic predictability with reduced equifinality. The Upper Wabash and Cedar Creek, two agriculture-dominated watersheds in Indiana, USA are considered as test beds to implement this multi-objective SWAT calibration. The proposed calibration approach is performed using remotely sensed Advanced Microwave Scanning Radiometer-Earth Observing System surface soil moisture (∼1 cm top soil) estimates (NASA's Aqua daily level-3 gridded land surface product-version 2) in sub-basin/HRU level together with observed streamflow data at the watershed's outlet. Although application of remote sensing data in calibration improves surface soil moisture simulation, other hydrologic components such as streamflow, evapotranspiration (ET) and deeper layer moisture content in SWAT remain less affected. An extension of this approach to apply root zone soil moisture estimates from limited field sensor data showed considerable improvement in the simulation of root zone moisture content and streamflow with corresponding observed data. Difference in relative sensitivity of parameters and reduced extent of uncertainty are also evident from the proposed method, especially for parameters related to the subsurface hydrologic processes. Regardless, precise representation of vertical soil moisture stratification at different layers is difficult with current SWAT ET depletion mechanism. While the results from this study show that root zone soil moisture can play a major role in SWAT calibration, more studies including various soil moisture data products are necessary to validate the proposed approach.

  9. [Estimation of PM2.5 Concentration over the Yangtze Delta Using Remote Sensing: Analysis of Spatial and Temporal Variations].

    PubMed

    Xu, Jian-hui; Jiang, Hong

    2015-09-01

    Satellite remote sensing retrieved aerosol optical thickness is widely used to monitor surface PM2.5 concentration. In order to monitor PM2.5 by remote sensing in the Yangtze delta, estimate model of PM2.5 concentration was constructed based on MODIS AOT, PM2.5 concentration data of the 36 ground air quality observation sites and meteorological data in 2013. Afterwards, the model estimated PM2.5 was validated by PM2.5 concentration data from the 17 ground air quality observation sites, and the results showed that the model estimation was higher. The correlation coefficient value of R2 between model estimation of PM2.5 concentration and the value of the ground monitoring of spring, summer, autumn and winter were 0. 45, 0. 50, 0. 58 and 0. 52, respectively. The variation characteristics of temporal and spatial was analyzed based on the long time PM2.5 data together with model estimated, and an increase trend of PM2.5 concentration was observed from 2000 to 2013, with the maximum concentration of PM2.5 (66. 2 µg.m-3 ± 19. 3 µg.m-3) in February and minimum in December (22.6 µg.m-3 ± 5. 9 µg.m-3). In addition, it was found that the distribution of PM2.5 concentration was of obvious features, displaying high value in south and low in north. Mass concentration of PM2.5 was peaked in the zone of urban agglomeration which was grouped to a delta-shaped region by Shanghai, Hangzhou and Nanjing, while the low value areas were in the forest away from city. The result suggested that MODIS AOT and meteorological data can be used to monitor regional PM2.5 by the established multi-linear regression model. PMID:26717669

  10. Analysis of Vegetation Within A Semi-Arid Urban Environment Using High Spatial Resolution Airborne Thermal Infrared Remote Sensing Data

    NASA Technical Reports Server (NTRS)

    Quattrochi, Dale A.; Ridd, Merrill K.

    1998-01-01

    High spatial resolution (5 m) remote sensing data obtained using the airborne Thermal Infrared Multispectral Scanner (TIMS) sensor for daytime and nighttime have been used to measure thermal energy responses for 2 broad classes and 10 subclasses of vegetation typical of the Salt Lake City, Utah urban landscape. Polygons representing discrete areas corresponding to the 10 subclasses of vegetation types have been delineated from the remote sensing data and are used for analysis of upwelling thermal energy for day, night, and the change in response between day and night or flux, as measured by the TIMS. These data have been used to produce three-dimensional graphs of energy responses in W/ sq m for day, night, and flux, for each urban vegetation land cover as measured by each of the six channels of the TIMS sensor. Analysis of these graphs provides a unique perspective for both viewing and understanding thermal responses, as recorded by the TIMS, for selected vegetation types common to Salt Lake City. A descriptive interpretation is given for each of the day, night, and flux graphs along with an analysis of what the patterns mean in reference to the thermal properties of the vegetation types surveyed in this study. From analyses of these graphs, it is apparent that thermal responses for vegetation can be highly varied as a function of the biophysical properties of the vegetation itself, as well as other factors. Moreover, it is also seen where vegetation, particularly trees, has a significant influence on damping or mitigating the amount of thermal radiation upwelling into the atmosphere across the Salt Lake City urban landscape. Published by Elsevier Science Ltd.

  11. Spatial-Temporal Analyses of Lightning Activities over Pakistan using Satellite Remote Sensing

    NASA Astrophysics Data System (ADS)

    Qaiser, Saddam; Imran Shahzad, Muhammad

    2016-07-01

    Lightning is a naturally occurring spectacular and powerful phenomenon often accompanied by thunder. Regardless, it's hazardous and responsible for thousands of deaths and property loss all over the globe.In Pakistan, this hazardous phenomenon mostly occurs in monsoon and pre-monsoon seasons. To prevent or at least minimize the unforeseen property damages and human casuality, we need to identify the vulnerable locations to lightning in Pakistan, but yet there have not been done any detailed study regarding the lightning hazards yet for Pakistan. In the present study for the years 2001 - 2014 lightning density mapping has been done by means of satellite Remote Sensing techniques. Lightning Image Sensor (LIS) datasets of locations and Time of Occurrence (TOA) are used to identify the lightning prone locations all over Pakistan. Efforts have been made to develop a technique that is helpful in generating the hazard maps of lighting in Pakistan on temporal basis by using spatio-temporal satellite images. These maps show frequency distribution trends of lightning in many regions of Pakistan that enable us to locate high, moderate and low lightning-susceptible areas. Results demonstrate that thunderstorm frequency is comparatively higher over the mountain and sub-mountain regions in the Punjab, Federally Administered Tribal Areas (FATA) and Khyber Pakhtoon Khwa (KPK) provinces. Interestingly lightning data showed a strong correlation between the FlashesYear and the El Niño and La Niña years. It is observed that about 40.1 % of lightning activities occurred during the monsoon followed by pre-monsoon with 39.7 %, which can possibly create synergistic and devastating effects in combination with heavy seasonal rainfall. A severe lightning event with 4559 flashes in just 3.08 seconds is also recorded on 8-Oct-2005 in Pakistan-India border near Azad Jammu Kashmir (AJK) and Jammu Kashmir. However, it is to be noted that on the same date Pakistan was hit by a major Earthquake

  12. Spatial navigation impairments among intellectually high-functioning adults with autism spectrum disorder: exploring relations with theory of mind, episodic memory, and episodic future thinking.

    PubMed

    Lind, Sophie E; Williams, David M; Raber, Jacob; Peel, Anna; Bowler, Dermot M

    2013-11-01

    Research suggests that spatial navigation relies on the same neural network as episodic memory, episodic future thinking, and theory of mind (ToM). Such findings have stimulated theories (e.g., the scene construction and self-projection hypotheses) concerning possible common underlying cognitive capacities. Consistent with such theories, autism spectrum disorder (ASD) is characterized by concurrent impairments in episodic memory, episodic future thinking, and ToM. However, it is currently unclear whether spatial navigation is also impaired. Hence, ASD provides a test case for the scene construction and self-projection theories. The study of spatial navigation in ASD also provides a test of the extreme male brain theory of ASD, which predicts intact or superior navigation (purportedly a systemizing skill) performance among individuals with ASD. Thus, the aim of the current study was to establish whether spatial navigation in ASD is impaired, intact, or superior. Twenty-seven intellectually high-functioning adults with ASD and 28 sex-, age-, and IQ-matched neurotypical comparison adults completed the memory island virtual navigation task. Tests of episodic memory, episodic future thinking, and ToM were also completed. Participants with ASD showed significantly diminished performance on the memory island task, and performance was positively related to ToM and episodic memory, but not episodic future thinking. These results suggest that (contra the extreme male brain theory) individuals with ASD have impaired survey-based navigation skills--that is, difficulties generating cognitive maps of the environment--and adds weight to the idea that scene construction/self-projection are impaired in ASD. The theoretical and clinical implications of these results are discussed. PMID:24364620

  13. Spatial Navigation Impairments Among Intellectually High-Functioning Adults With Autism Spectrum Disorder: Exploring Relations With Theory of Mind, Episodic Memory, and Episodic Future Thinking

    PubMed Central

    2013-01-01

    Research suggests that spatial navigation relies on the same neural network as episodic memory, episodic future thinking, and theory of mind (ToM). Such findings have stimulated theories (e.g., the scene construction and self-projection hypotheses) concerning possible common underlying cognitive capacities. Consistent with such theories, autism spectrum disorder (ASD) is characterized by concurrent impairments in episodic memory, episodic future thinking, and ToM. However, it is currently unclear whether spatial navigation is also impaired. Hence, ASD provides a test case for the scene construction and self-projection theories. The study of spatial navigation in ASD also provides a test of the extreme male brain theory of ASD, which predicts intact or superior navigation (purportedly a systemizing skill) performance among individuals with ASD. Thus, the aim of the current study was to establish whether spatial navigation in ASD is impaired, intact, or superior. Twenty-seven intellectually high-functioning adults with ASD and 28 sex-, age-, and IQ-matched neurotypical comparison adults completed the memory island virtual navigation task. Tests of episodic memory, episodic future thinking, and ToM were also completed. Participants with ASD showed significantly diminished performance on the memory island task, and performance was positively related to ToM and episodic memory, but not episodic future thinking. These results suggest that (contra the extreme male brain theory) individuals with ASD have impaired survey-based navigation skills—that is, difficulties generating cognitive maps of the environment—and adds weight to the idea that scene construction/self-projection are impaired in ASD. The theoretical and clinical implications of these results are discussed. PMID:24364620

  14. Optimal spatial sampling techniques for ground truth data in microwave remote sensing of soil moisture

    NASA Technical Reports Server (NTRS)

    Rao, R. G. S.; Ulaby, F. T.

    1977-01-01

    The paper examines optimal sampling techniques for obtaining accurate spatial averages of soil moisture, at various depths and for cell sizes in the range 2.5-40 acres, with a minimum number of samples. Both simple random sampling and stratified sampling procedures are used to reach a set of recommended sample sizes for each depth and for each cell size. Major conclusions from statistical sampling test results are that (1) the number of samples required decreases with increasing depth; (2) when the total number of samples cannot be prespecified or the moisture in only one single layer is of interest, then a simple random sample procedure should be used which is based on the observed mean and SD for data from a single field; (3) when the total number of samples can be prespecified and the objective is to measure the soil moisture profile with depth, then stratified random sampling based on optimal allocation should be used; and (4) decreasing the sensor resolution cell size leads to fairly large decreases in samples sizes with stratified sampling procedures, whereas only a moderate decrease is obtained in simple random sampling procedures.

  15. Assessment of Biogenic Terpenoid Emission Inventories in Asia using Remotely Sensed Spatial and Temporal Surrogate Data

    NASA Astrophysics Data System (ADS)

    Kim, H. K.; Woo, J. H.; Choi, K. C.; Lee, Y. M.; Kim, Y.

    2014-12-01

    Among biogenic volatile organic compound (BVOC) species, the most comprehensively studied species are isoprene and monoterpene (terpenoid) due to their significant impacts on global and regional total VOC emission budget and ozone and aerosol formation mechanisms. Biogenic terpenoid emission inventories have been often assessed on a global basis and consistently available on model grid system units to support climate and chemical transport modeling. However, little of these have been assessed based on the political units such as countries and provinces. On the basis of political boundaries in Asia, we assembled and compared a large number of terpenoid emission estimates including currently published or reported sources. We assessed these terpenoid emission estimates in the context of the spatial and temporal consistency. Since the biogenic terpenoid emission inventories commonly use leaf biomass density, solar radiation and temperature as driving variables, we used the MODIS Gross Primary Productivity (GPP) and Land Surface Temperature (LST) datasets as surrogates to correlate with the terpenoid emission estimates in Asia. Based on our current assessment, we will discuss about the current status of the biogenic terpenoid emission inventories in Asia.

  16. Spatial and temporal variability in surface ozone at a high elevation remote site in Nepal

    NASA Astrophysics Data System (ADS)

    Moore, G. W. K.; Abernethy, S.; Semple, J. L.

    2009-07-01

    Ozone is an important atmospheric constituent due to its role as both a greenhouse gas and an oxidant. Recent measurements in the Mount Everest region indicate the presence of ozone at elevations from 5000 to 9000 m a.s.l. that are the result of both stratospheric and tropospheric sources. Here we examine the temporal variability in the surface ozone concentration measurements from the ABC-Pyramid Observatory in the Mount Everest region during 2006 and compare it to the total column ozone data from the OMI instrument as well as meteorological fields from the ECMWF Interim Reanalysis. Both the surface ozone at and the total column ozone over the ABC-Pyramid Observatory site have maxima in the pre-monsoon period. We show that during this period, there is a statistically significant correlation between the two suggesting that the stratosphere was an important contributor to the high levels of ozone observed during the period. There was a hiatus in the monsoon in June that resulted in a return of westerlies over northern Indian and southern Tibet and as a result, the aforementioned correlation extended into June. No such correlation exists during the monsoon and post-monsoon periods. Spatial correlation maps between the surface ozone and total column ozone as well as meteorological fields from the ECMWF Interim Reanalysis support the contention that there is a significant stratospheric contribution in the pre-monsoon period that is absent during and after the monsoon.

  17. Spatially explicit forest characteristics of Europe through integrating Forest Inventory and Remotely sensed data

    NASA Astrophysics Data System (ADS)

    Moreno, Adam; Neumann, Mathias; Hasenauer, Hubert

    2015-04-01

    Carbon stock estimates are critical for any carbon trading scheme or climate change mitigation strategy. Understanding the carbon allocation and the structure of its ecosystem further help scientists and policy makers develop realistic plans for utilizing these systems. Forests play an important role in global carbon storage. Therefore it is imperative to include forests in any climate change mitigation and/or carbon trading scheme. Currently there is no estimate of forest carbon stocks and allocation nor forest structure maps throughout Europe. We compiled National Forest Inventory (NFI) data from 12 European countries. We integrated the NFI data with Net Primary Production data (NPP) from Moderate Resolution Imaging Spectroradiometer (MODIS), tree height data from Light Detection and Ranging (LIDAR) data from the Geosciences Laser Altimeter System (GLAS) instrument, and various other spatially explicit data sets. Through this process of integration of terrestrial and space based data we produced wall-to-wall forest characteristics maps of Europe. These maps include forest age, basal area, average diameter at breast height, total carbon, carbon allocation (stem, branches, leaves, roots), and other characteristics derived from forest inventory data. These maps cover Europe - including countries without terrestrial data - and give one coherent harmonized data set of current forest structure and carbon storage on a 16x16km resolution. The methodology presented here has the potential to be used world-wide in regions with data limitations or with limited access to data.

  18. Toward the modeling of land use change: A spatial analysis using remote sensing and historical data

    NASA Technical Reports Server (NTRS)

    Honea, R. B.

    1976-01-01

    It was hypothesized that the chronological observation of land use change could be shown to follow a predictable pattern and these patterns could be correlated with other statistical data to develop transition probabilities suitable for modeling purposes. A literature review and preliminary research, however, indicated a totally stochastic approach was not practical for simulating land use change and thus a more deterministic approach was adopted. The approach used assumes the determinants of the land use conversion process are found in the market place, where land transactions among buyers and sellers occur. Only one side of the market transaction process is studied, however, namely, the purchaser's desires in securing an ideal or suitable site. The problem was to identify the ideal qualities, quantities or attributes desired in an industrial site (or housing development), and to formulate a general algorithmic statement capable of identifying potential development sites. Research procedures involved developing a list of variables previously noted in the literature to be related to site selection and streamlining the list to a set suitable for statistical testing. A sample of 157 industries which have located (or relocated) in the 16-county Knoxville metropolitan region since 1950 was selected for industrial location analysis. Using NASA color infrared photography and Tennessee Valley Authority historical aerial photography, data were collected on the spatial characteristics of each industrial location event. These data were then subjected to factor analysis to determine the interrelations of variables.

  19. Benthic communities at two remote Pacific coral reefs: effects of reef habitat, depth, and wave energy gradients on spatial patterns.

    PubMed

    Williams, Gareth J; Smith, Jennifer E; Conklin, Eric J; Gove, Jamison M; Sala, Enric; Sandin, Stuart A

    2013-01-01

    Kingman Reef and Palmyra Atoll in the central Pacific are among the most remote coral reefs on the planet. Here we describe spatial patterns in their benthic communities across reef habitats and depths, and consider these in the context of oceanographic gradients. Benthic communities at both locations were dominated by calcifying organisms (54-86% cover), namely hard corals (20-74%) and crustose coralline algae (CCA) (10-36%). While turf algae were relatively common at both locations (8-22%), larger fleshy macroalgae were virtually absent at Kingman (<1%) and rare at Palmyra (0.7-9.3%). Hard coral cover was higher, but with low diversity, in more sheltered habitats such as Palmyra's backreef and Kingman's patch reefs. Almost exclusive dominance by slow-growing Porites on Kingman's patch reefs provides indirect evidence of competitive exclusion, probably late in a successional sequence. In contrast, the more exposed forereef habitats at both Kingman and Palmyra had higher coral diversity and were characterized by fast-growing corals (e.g., Acropora and Pocillopora), indicative of more dynamic environments. In general at both locations, soft coral cover increased with depth, likely reflecting increasingly efficient heterotrophic abilities. CCA and fleshy macroalgae cover decreased with depth, likely due to reduced light. Cover of other calcified macroalgae, predominantly Halimeda, increased with depth. This likely reflects the ability of many calcifying macroalgae to efficiently harvest light at deeper depths, in combination with an increased nutrient supply from upwelling promoting growth. At Palmyra, patterns of hard coral cover with depth were inconsistent, but cover peaked at mid-depths at Kingman. On Kingman's forereef, benthic community composition was strongly related to wave energy, with hard coral cover decreasing and becoming more spatially clustered with increased wave energy, likely as a result of physical damage leading to patches of coral in localized

  20. Benthic communities at two remote Pacific coral reefs: effects of reef habitat, depth, and wave energy gradients on spatial patterns

    PubMed Central

    Conklin, Eric J.; Gove, Jamison M.; Sala, Enric; Sandin, Stuart A.

    2013-01-01

    Kingman Reef and Palmyra Atoll in the central Pacific are among the most remote coral reefs on the planet. Here we describe spatial patterns in their benthic communities across reef habitats and depths, and consider these in the context of oceanographic gradients. Benthic communities at both locations were dominated by calcifying organisms (54–86% cover), namely hard corals (20–74%) and crustose coralline algae (CCA) (10–36%). While turf algae were relatively common at both locations (8–22%), larger fleshy macroalgae were virtually absent at Kingman (<1%) and rare at Palmyra (0.7–9.3%). Hard coral cover was higher, but with low diversity, in more sheltered habitats such as Palmyra’s backreef and Kingman’s patch reefs. Almost exclusive dominance by slow-growing Porites on Kingman’s patch reefs provides indirect evidence of competitive exclusion, probably late in a successional sequence. In contrast, the more exposed forereef habitats at both Kingman and Palmyra had higher coral diversity and were characterized by fast-growing corals (e.g., Acropora and Pocillopora), indicative of more dynamic environments. In general at both locations, soft coral cover increased with depth, likely reflecting increasingly efficient heterotrophic abilities. CCA and fleshy macroalgae cover decreased with depth, likely due to reduced light. Cover of other calcified macroalgae, predominantly Halimeda, increased with depth. This likely reflects the ability of many calcifying macroalgae to efficiently harvest light at deeper depths, in combination with an increased nutrient supply from upwelling promoting growth. At Palmyra, patterns of hard coral cover with depth were inconsistent, but cover peaked at mid-depths at Kingman. On Kingman’s forereef, benthic community composition was strongly related to wave energy, with hard coral cover decreasing and becoming more spatially clustered with increased wave energy, likely as a result of physical damage leading to patches of

  1. Spatial heterogeneity and temporal evolution of malaria transmission risk in Dakar, Senegal, according to remotely sensed environmental data

    PubMed Central

    2010-01-01

    Background The United Nations forecasts that by 2050, more than 60% of the African population will live in cities. Thus, urban malaria is considered an important emerging health problem in that continent. Remote sensing (RS) and geographic information systems (GIS) are useful tools for addressing the challenge of assessing, understanding and spatially focusing malaria control activities. The objectives of the present study were to use high spatial resolution SPOT (Satellite Pour l'Observation de la Terre) satellite images to identify some urban environmental factors in Dakar associated with Anopheles arabiensis densities, to assess the persistence of these associations and to describe spatial changes in at-risk environments using a decadal time scale. Methods Two SPOT images from the 1996 and 2007 rainy seasons in Dakar were processed to extract environmental factors, using supervised classification of land use and land cover, and a calculation of NDVI (Normalized Difference Vegetation Index) and distance to vegetation. Linear regressions were fitted to identify the ecological factors associated with An. arabiensis aggressiveness measured in 1994-97 in the South and centre districts of Dakar. Risk maps for populated areas were computed and compared for 1996 and 2007 using the results of the statistical models. Results Almost 60% of the variability in anopheline aggressiveness measured in 1994-97 was explained with only one variable: the built-up area in a 300-m radius buffer around the catching points. This association remained stable between 1996 and 2007. Risk maps were drawn by inverting the statistical association. The total increase of the built-up areas in Dakar was about 30% between 1996 and 2007. In proportion to the total population of the city, the population at high risk for malaria fell from 32% to 20%, whereas the low-risk population rose from 29 to 41%. Conclusions Environmental data retrieved from high spatial resolution SPOT satellite images were

  2. Baclofen ameliorates spatial working memory impairments induced by chronic cerebral hypoperfusion via up-regulation of HCN2 expression in the PFC in rats.

    PubMed

    Luo, Pan; Chen, Cheng; Lu, Yun; Fu, TianLi; Lu, Qing; Xu, Xulin; Li, Changjun; He, Zhi; Guo, Lianjun

    2016-07-15

    Chronic cerebral hypoperfusion (CCH) causes memory deficits and increases the risk of vascular dementia (VD) through several biologically plausible pathways. However, whether CCH causes prefrontal cortex (PFC)-dependent spatial working memory impairments and Baclofen, a GABAB receptor agonist, could ameliorate the impairments is still not clear especially the mechanisms underlying the process. In this study, rats were subjected to permanent bilateral occlusion of the common carotid arteries (two-vessel occlusion, 2VO) to induce CCH. Two weeks later, rats were treated with 25mg/kg Baclofen (intraperitioneal injection, i.p.) for 3 weeks. Spatial working memory was evaluated in a Morris water maze using a modified delayed matching-to-place (DMP) procedure. Western blotting and immunohistochemistry were used to quantify the protein levels and protein localization. Our results showed that 2VO caused striking spatial working memory impairments, accompanied with a decreased HCN2 expression in PFC, but the protein levels of protein gene product 9.5 (PGP9.5, a neuron specific protein), glial fibrillary acidic protein (GFAP), synaptophysin (SYP), brain-derived neurotrophic factor (BDNF), parvalbumin (PV) and HCN1 were not distinguishably changed as compared with sham-operated rats. Baclofen treatment significantly improved the spatial working memory impairments caused by 2VO, accompanied with a reversion of 2VO-induced down-regulation of HCN2. Furthermore, there was a co-localization of HCN2 subunits and parvalbumin-positive neurons in PFC. Therefore, HCN2 may target inhibitory interneurons that is implicated in working memory processes, which may be a possible mechanism of the up-regulation of HCN2 by Baclofen treatment that reliefs spatial working memory deficits in rats with CCH. PMID:27085590

  3. Spatial analysis of suicide mortality in Australia: investigation of metropolitan-rural-remote differentials of suicide risk across states/territories.

    PubMed

    Cheung, Yee Tak Derek; Spittal, Matthew J; Pirkis, Jane; Yip, Paul Siu Fai

    2012-10-01

    Studies of suicide epidemiology in regions of Australia have been conducted, but the spatial pattern in the whole country has not been fully investigated. This study aimed at visualizing the sex-specific suicide pattern over the country from 2004 to 2008, and studying the metropolitan-rural-remote differentials of suicide across all states/territories. We applied a Poisson hierarchical model to yield smoothed sex specific, age standardized mortality ratios of suicide in all postal areas, and compiled the age-standardized suicide rates across different levels of remoteness and different jurisdictions. We identified the area variation of suicide risk across states/territories, and metropolitan-rural-remote differential with rates higher in rural and remote areas for males. Spatial clusters of some high risk postal areas were also identified. Socio-economic deprivation, compositional factors, high risks for Indigenous people and low access to mental health service are the underlying explanations of the elevation of suicide risk in some areas. These findings suggest that it is important to take geographical variations in suicide risk into account in national policy making. Particular suicide prevention interventions might be targeted at males living in remote areas, and some localized areas in metropolitan zones. PMID:22771036

  4. Spatial Estimation of Timber Production and Carbon in Harvested Wood Products Using Remote Sensing

    NASA Astrophysics Data System (ADS)

    Ling, P. Y.; Baiocchi, G.; Huang, C.

    2014-12-01

    Accurate estimation of the annual production of different kinds of timbers at different locations has many science and policy implications. For example, timber type information is needed for accurate estimation of the amount and life cycle of carbon stored in the harvested wood product (HWP) pool, and possible transport of carbon in wood products through trade. Several attempts have been made to estimate the carbon storage in the HWP, regardless which approach to use, information of the annual timber production are required. A statistic model has been developed to estimate the annual roundwood production at the county level. The inputs of the model includes forest disturbance area calculated using the VCT algorithm derived from the Landsat time series stack, a forest type map, and timber product output (TPO) data collected from wood processing mills by the USFS. The model is applied to North Carolina, a state with a large forestry sector and where harvesting and logging are a primary forest disturbance type. Ten-fold cross validation were done to the preliminary estimation for each type of HWP. The root mean square errors range between 13.6 and 31.5 for hardwood types; and between 1.3 and 55.6 for softwood types. The model is empirical as it depends on the local information on forest disturbance, forest types, and the amount of the roundwood output. However, the approach of the model can be used to apply to other areas with the local information provided. The result can be served as a starting point in spatial estimation of carbon storage in HWP.

  5. E-Learning in Photogrammetry, Remote Sensing and Spatial Information Science

    NASA Astrophysics Data System (ADS)

    Vyas, Anjana; König, Gerhard

    2016-06-01

    Science and technology are evolving leaps and bounds. The advancements in GI-Science for natural and built environment helps in improving the quality of life. Learning through education and training needs to be at par with those advancements, which plays a vital role in utilization of technology. New technologies that creates new opportunities have enabled Geomatics to broaden the horizon (skills and competencies). Government policies and decisions support the use of geospatial science in various sectors of governance. Mapping, Land management, Urban planning, Environmental planning, Industrialization are some of the areas where the geomatics has become a baseline for decision making at national level. There is a need to bridge the gap between developments in geospatial science and its utilization and implementation. To prepare a framework for standardisation it is important to understand the theories of education and prevailing practices, with articulate goals exploring variety of teaching techniques. E-Learning is an erudition practice shaped for facilitating learning and improving performance by creating, using and managing appropriate technological processes and resources through digital and network-enabled technology. It is a shift from traditional education or training to ICT-based flexible and collaborative learning based on the community of learners, academia, professionals, experts and facilitators. Developments in e-learning is focussed on computer assisted learning which has become popular because of its potential for providing more flexible access to content and instruction at any time, from any place (Means et al, 2009). With the advent of the geo-spatial technology, fast development in the software and hardware, the demand for skilled manpower is increasing and the need is for training, education, research and dissemination. It suggests inter-organisational cooperation between academia, industry, government and international collaboration. There is a

  6. Spatial and Temporal Variability of Remotely Sensed Ocean Color Parameters in Coral Reef Regions

    NASA Astrophysics Data System (ADS)

    Otis, Daniel Brooks

    The variability of water-column absorption due to colored dissolved organic matter (CDOM) and phytoplankton in coral reef regions is the focus of this study. Hydrographic and CDOM absorption measurements made on the Bahamas Banks and in Exuma Sound during the spring of 1999 and 2000 showed that values of salinity and CDOM absorption at 440nm were higher on the banks (37.18 psu, 0.06 m. -1), compared to Exuma Sound (37.04 psu, 0.03 m. -1). Spatial patternsof CDOM absorption in Exuma Sound revealed that plumes of CDOM-rich water flow into Exuma Sound from the surrounding banks. To examine absorption variability in reef regions throughout the world, a thirteen-year time series of satellite-derived estimates of water-column absorption due to CDOM and phytoplankton were created from Sea-viewing Wide Field-of-view Sensor (SeaWiFS) and Moderate Resolution Imaging Spectroradiometer (MODIS) data. Time series data extracted adjacent to coral reef regions showed that variability in absorption depends on oceanographic conditions such as circulation patterns and winds as well as proximity to sources of light-absorbing materials that enter the water column, such as from terrestrial runoff. Waters near reef regions are generally clear, exhibiting a lower "baseline" level of CDOM absorption of approximately 0.01 m. -1 at 443nm. The main differences between regions lie in the periodsduring the year when increased levels of absorption are observed, which can be triggered by inputs of terrestrially-derived material, as in the Great Barrier Reef lagoon, or wind-driven upwelling as in the Andaman Sea and eastern Pacific Ocean near Panama. The lowest CDOM absorption levels found were approximately 0.003 m. -1 at 443nm near the islands of Palau and Yap, which are removed fromsources of colored materials. The highest absorption levels near reefs were associated with wind-driven upwelling during the northeast monsoon on the Andaman coast of Thailand where values of CDOM absorption at 443nm

  7. Real-Time Integrity Monitoring of Stored Geo-Spatial Data Using Forward-Looking Remote Sensing Technology

    NASA Technical Reports Server (NTRS)

    Young, Steven D.; Harrah, Steven D.; deHaag, Maarten Uijt

    2002-01-01

    Terrain Awareness and Warning Systems (TAWS) and Synthetic Vision Systems (SVS) provide pilots with displays of stored geo-spatial data (e.g. terrain, obstacles, and/or features). As comprehensive validation is impractical, these databases typically have no quantifiable level of integrity. This lack of a quantifiable integrity level is one of the constraints that has limited certification and operational approval of TAWS/SVS to "advisory-only" systems for civil aviation. Previous work demonstrated the feasibility of using a real-time monitor to bound database integrity by using downward-looking remote sensing technology (i.e. radar altimeters). This paper describes an extension of the integrity monitor concept to include a forward-looking sensor to cover additional classes of terrain database faults and to reduce the exposure time associated with integrity threats. An operational concept is presented that combines established feature extraction techniques with a statistical assessment of similarity measures between the sensed and stored features using principles from classical detection theory. Finally, an implementation is presented that uses existing commercial-off-the-shelf weather radar sensor technology.

  8. Spatial distribution of the electrical potential and ion concentration in the downstream area of atmospheric pressure remote plasma

    NASA Astrophysics Data System (ADS)

    Mishin, M. V.; Protopopova, V. S.; Uvarov, A. A.; Alexandrov, S. E.

    2014-10-01

    This paper presents the results from an experimental study of the ion flux characteristics behind the remote plasma zone in a vertical tube reaction chamber for atmospheric pressure plasma enhanced chemical vapor deposition. Capacitively coupled radio frequency plasma was generated in pure He and gas mixtures: He-Ar, He-O2, He-TEOS. We previously used the reaction system He-TEOS for the synthesis of self-assembled structures of silicon dioxide nanoparticles. It is likely that the electrical parameters of the area, where nanoparticles have been transported from the synthesis zone to the substrate, play a significant role in the self-organization processes both in the vapor phase and on the substrate surface. The results from the spatial distribution of the electrical potential and ion concentration in the discharge downstream area measured by means of the external probe of original design and the special data processing method are demonstrated in this work. Positive and negatives ions with maximum concentrations of 106-107 cm-3 have been found at 10-80 mm distance behind the plasma zone. On the basis of the revealed distributions for different gas mixtures, the physical model of the observed phenomena is proposed. The model illustrates the capability of the virtual ion emitter formation behind the discharge gap and the presence of an extremum of the electrical potential at the distance of approximately 10-2-10-1 mm from the grounded electrode.

  9. Integrating geographic information systems and remote sensing with spatial econometric and mixed logit models for environmental valuation

    NASA Astrophysics Data System (ADS)

    Wells, Aaron Raymond

    This research focuses on the Emory and Obed Watersheds in the Cumberland Plateau in Central Tennessee and the Lower Hatchie River Watershed in West Tennessee. A framework based on market and nonmarket valuation techniques was used to empirically estimate economic values for environmental amenities and negative externalities in these areas. The specific techniques employed include a variation of hedonic pricing and discrete choice conjoint analysis (i.e., choice modeling), in addition to geographic information systems (GIS) and remote sensing. Microeconomic models of agent behavior, including random utility theory and profit maximization, provide the principal theoretical foundation linking valuation techniques and econometric models. The generalized method of moments estimator for a first-order spatial autoregressive function and mixed logit models are the principal econometric methods applied within the framework. The dissertation is subdivided into three separate chapters written in a manuscript format. The first chapter provides the necessary theoretical and mathematical conditions that must be satisfied in order for a forest amenity enhancement program to be implemented. These conditions include utility, value, and profit maximization. The second chapter evaluates the effect of forest land cover and information about future land use change on respondent preferences and willingness to pay for alternative hypothetical forest amenity enhancement options. Land use change information and the amount of forest land cover significantly influenced respondent preferences, choices, and stated willingness to pay. Hicksian welfare estimates for proposed enhancement options ranged from 57.42 to 25.53, depending on the policy specification, information level, and econometric model. The third chapter presents economic values for negative externalities associated with channelization that affect the productivity and overall market value of forested wetlands. Results of robust

  10. Anthropogenic habitat disturbance and the dynamics of hantavirus using remote sensing, GIS, and a spatially explicit agent-based model

    NASA Astrophysics Data System (ADS)

    Cao, Lina

    Sin Nombre virus (SNV), a strain of hantavirus, causes hantavirus pulmonary syndrome (HPS) in humans, a deadly disease with high mortality rate (>50%). The primary virus host is deer mice, and greater deer mice abundance has been shown to increase the human risk of HPS. There is a great need in understanding the nature of the virus host, its temporal and spatial dynamics, and its relation to the human population with the purpose of predicting human risk of the disease. This research studies SNV dynamics in deer mice in the Great Basin Desert of central Utah, USA using multiyear field data and integrated geospatial approaches including remote sensing, Geographic Information System (GIS), and a spatially explicit agent-based model. The goal is to advance our understanding of the important ecological and demographic factors that affect the dynamics of deer mouse population and SNV prevalence. The primary research question is how climate, habitat disturbance, and deer mouse demographics affect deer mouse population density, its movement, and SNV prevalence in the sagebrush habitat. The results show that the normalized difference vegetation index (NDVI) and the enhanced vegetation index (EVI) can be good predictors of deer mouse density and the number of infected deer mice with a time lag of 1.0 to 1.3 years. This information can be very useful in predicting mouse abundance and SNV risk. The results also showed that climate, mouse density, sex, mass, and SNV infection had significant effects on deer mouse movement. The effect of habitat disturbance on mouse movement varies according to climate conditions with positive relationship in predrought condition and negative association in postdrought condition. The heavier infected deer mice moved the most. Season and disturbance alone had no significant effects. The spatial agent-based model (SABM) simulation results show that prevalence was negatively related to the disturbance levels and the sensitivity analysis showed that

  11. Treadmill exercise alleviates impairment of spatial learning ability through enhancing cell proliferation in the streptozotocin-induced Alzheimer’s disease rats

    PubMed Central

    Sim, Young-Je

    2014-01-01

    Alzheimer’s disease is the most common cause of dementia. This disease is a progressive and irreversible brain disorder accompanied with severe learning and memory impairment. Exercise increases cognitive ability, attenuates motor deficits, increases new neuron formation, and ameliorates neurological impairments in several neurodegenerative diseases. This study investigated the effects of treadmill exercise on spatial learning ability in relation with cell proliferation in the hippocampus. The rat model of Alzheimer’s disease was induced by intracerebroventricular (ICV) injection of streptozotocin (STZ) using a stereotaxic instrument. The rats in the exercise groups were forced to run on a treadmill for once 30 min daily for 28 consecutive days starting at 3 days after the ICV injection of STZ. Radial 8-arm maze test was conducted for the spatial learning ability. New neuron formation in the hippocampus was detected by 5-bromo-2’-deoxyuridine (BrdU) immunohistochemistry. Brain-derived neurotrophic factor (BDNF) and tyrosine kinase B (TrkB) expressions were examined by western blot analysis. The present results show that ICV injection of STZ impaired spatial learning ability. Decreased cell proliferation with decrement of BDNF and TrkB expressions in the hippocampus were observed in the STZ-induced Alzheimer’s disease rats. However, treadmill exercise alleviated deficits of spatial learning ability. Treadmill exercise enhanced cell proliferation and increased BDNF and TrkB expressions in the rats with ICV injection of STZ. The present study suggests that treadmill exercise can be a useful strategy for treating memory impairment induced by several neurodegenerative diseases. PMID:24877042

  12. Pre-weaning dietary iron deficiency impairs spatial learning and memory in the cognitive holeboard task in piglets

    PubMed Central

    Antonides, Alexandra; Schoonderwoerd, Anne C.; Scholz, Gabi; Berg, Brian M.; Nordquist, Rebecca E.; van der Staay, Franz Josef

    2015-01-01

    Iron deficiency is the most common nutritional deficiency in humans, affecting more than two billion people worldwide. Early-life iron deficiency can lead to irreversible deficits in learning and memory. The pig represents a promising model animal for studying such deficits, because of its similarities to humans during early development. We investigated the effects of pre-weaning dietary iron deficiency in piglets on growth, blood parameters, cognitive performance, and brain histology later in life. Four to six days after birth, 10 male sibling pairs of piglets were taken from 10 different sows. One piglet of each pair was given a 200 mg iron dextran injection and fed a control milk diet for 28 days (88 mg Fe/kg), whereas the other sibling was given a saline injection and fed an iron deficient (ID) milk diet (21 mg Fe/kg). Due to severely retarded growth of two of the ID piglets, only eight ID piglets were tested behaviorally. After dietary treatment, all piglets were fed a balanced commercial pig diet (190–240 mg Fe/kg). Starting at 7.5 weeks of age, piglets were tested in a spatial cognitive holeboard task. In this task, 4 of 16 holes contain a hidden food reward, allowing measurement of working (short-term) memory and reference (long-term) memory (RM) simultaneously. All piglets received 40–60 acquisition trials, followed by a 16-trial reversal phase. ID piglets showed permanently retarded growth and a strong decrease in blood iron parameters during dietary treatment. After treatment, ID piglets' blood iron values restored to normal levels. In the holeboard task, ID piglets showed impaired RM learning during acquisition and reversal. Iron staining at necropsy at 12 weeks of age showed that ID piglets had fewer iron-containing cells in hippocampal regions CA1 and dentate gyrus (DG). The number of iron-containing cells in CA3 correlated positively with the average RM score during acquisition across all animals. Our results support the hypothesis that early

  13. The Optimization of Spatial, Spectral, and Temporal Resolution for Constraining Eruption Style on Earth and Io with Thermal Remote Sensing

    NASA Astrophysics Data System (ADS)

    Davies, A. G.; Keszthelyi, L. P.; Harris, A. J.

    2009-12-01

    Volcanic eruptions on Io and Earth are monitored by a variety of thermal remote sensing instruments. While higher resolution data are always desirable, we have developed methodologies to constrain the style of volcanic eruption using low spatial, spectral, and temporal resolution data. For the volcanic moon Io, this is necessitated by the limits of spacecraft and Earth-based telescopic observations. Eruption style can be classified using the concept of "thermal signature" which focuses on the temporal evolution of thermal emission spectra [1]. We find that the ratio of the emission at 2 µm and 5 µm, and how this ratio changes temporally, is often diagnostic of effusive eruption style, even in low spatial resolution data [2]. Tests using ground-based thermal data for terrestrial “ground truth” cases show that this classification system is equally valid for Earth. A square meter of an active lava lake on Io looks very similar to a square meter of an active lava lake on Earth. The same goes for pahoehoe flows. This validation of “thermal signature” means that appropriate physical models can be selected to interpret the data. On Io, the scale of eruptions can utterly dwarf their terrestrial counterparts. “Outburst” eruptions, known to be caused by extensive lava fountaining, can radiate >1013 W. The smallest thermal anomalies detected on Io in thermal infrared data are still larger than any contemporaneous mafic volcanic activity on Earth. The large volumes of lava erupted on Io (e.g., >56 km3 at Pillan in 1997) are an expression of internal tidal heating. It may be that high compressive stresses in the lower lithosphere inhibit magma ascent, and so only relatively large volumes of magma can overcome this “stress barrier” and reach the surface. The results of the “thermal signature” analysis [2] can be used as an aid in the planning of future space-borne instruments that can be used for volcano monitoring on Io, as well as on Earth. This work was

  14. Spatial distribution and temporal trends of mercury and arsenic in remote timberline coniferous forests, eastern of the Tibet Plateau, China.

    PubMed

    Tang, Ronggui; Wang, Haiming; Luo, Ji; Sun, Shouqin; Gong, Yiwen; She, Jia; Chen, Youchao; Dandan, Yang; Zhou, Jun

    2015-08-01

    An intensive investigation was conducted to study the spatial distribution and temporal variety trend of mercury and arsenic in plant tissue and soil profile in the eastern of the Tibet Plateau and to explore the possible sources of these two elements. At present, rare information is available on mercury (Hg) and arsenic (As) of timberline forests in the Tibet Plateau. Here, we present preliminary results on these two elements in leaves, twigs, root, litterfall, and soil. Geostatistical analyst of the ArcGIS 10.0 was used to determine the trait of spatial distribution of these two elements. Total arsenic (TAs) mean concentrations in the leaves, twigs, root, litterfall, and A- and C-layer soil ranged from 0.12 mg kg(-1) (n = 60), 0.35 mg kg(-1) (n = 60), 0.48 mg kg(-1) (n = 42), 1.52 mg kg(-1) (n = 84), 16.51 mg kg(-1) (n = 69), and 26.72 mg kg(-1) (n = 69), respectively. Total Hg (THg) mean concentrations in leaves, twigs, root, litterfall, and A- and C-layer soil were 0.0121 mg kg(-1) (n = 60), 0.0078 mg kg(-1) (n = 60), 0.0171 mg kg(-1) (n = 42), 0.0479 mg kg(-1) (n = 84), 0.0852 mg kg(-1) (n = 75), and 0.0251 mg kg(-1) (n = 75), respectively. In general, litterfall trended to accumulate high concentrations of Hg and As. Mercury in the timberline forest showed an increasing trend, whereas arsenic concentrations showed a decreasing trend in A-layer soil and an increasing trend in C-layer soil due to the easy mobile ability of As. Southwest and southeast monsoon could be the influencing factors, and Hg emission from India and China was the possible source of this study area through using a HYSPLIT (Hybrid Single-Particle Lagrangian Integrated Trajectory) model. It is believed that these observations may offer scientists and policymakers additional understanding of Hg and As concentrations in the remote timberline area, eastern of the Tibet Plateau. PMID:25850747

  15. Remote sensing and spatially distributed erosion models as a tool to really understand biocrust effects on soil erosion

    NASA Astrophysics Data System (ADS)

    Rodriguez-Caballero, Emilio; Chamizo, Sonia; Román, Raul; Roncero, Beatriz; Weber, Bettina; Jetten, Victor; Cantón, Yolanda

    2016-04-01

    Since publication of the first Ecological Stides volume on biological soil crusts (biocrusts) in 2003, numerous studies have been conducted trying to understand the role of biocrusts in runoff generation and water erosion. Most of them considered these communities as one of the most important stabilizing factors dryland regions. However, these studies were concentrated only on patch or hillslope scales, and there is a lack of information on biocrust interactions with other surface components at catchment scale. Even on fine textured soils, where biocrusts increase water infiltration, they act as runoff source when compared to vegetation. Run-on from biocrusted areas may be harvested by downslope vegetation, but sometimes it may promote downslope erosion. Thus, to really understand the effect of biocrusts on soil erosion, studies on larger scales, preferably on a catchment scale are needed. For this we developed a new approach, based on field measurements and remote sensing techniques, to include biocrust effects in physically-based runoff and erosion modeling. Doing this we were able to analyze how runoff generated in biocrust areas is redistributed within the landscape and its effect on catchment water erosion. The Limburg Soil Erosion Model (LISEM) was used to parameterize and simulate the effects of biocrusts on soil erosion in a small badlands catchment, where biocrusts represent one of the main surface components. Biocrust stability and cohesion were measured in the field, their hydrological properties were obtained from runoff plots, and their cover and spatial distribution was estimated from a hyperspectral image by linear mixture analysis. Then, the model was run under different rainfall intensities and final runoff and erosion rates were compared with field data measured at the catchment outlet. Moreover, these results were compared with the hypothetical scenario in which biocrusts were removed, simulating human disturbances or climatic change effects on

  16. Spatial evapotranspiration, rainfall and land use data in water accounting - Part 1: Review of the accuracy of the remote sensing data

    NASA Astrophysics Data System (ADS)

    Karimi, P.; Bastiaanssen, W. G. M.

    2014-01-01

    The scarcity of water encourages scientists to develop new analytical tools to enhance water resource management. Water accounting and distributed hydrological models are examples of such tools. Water accounting needs accurate input data for adequate descriptions of water distribution and water depletion in river basins. Ground-based observatories are decreasing, and remote sensing data is a suitable alternative to measure the required input variables. This paper reviews the reliability of remote sensing algorithms to accurately determine the spatial distribution of actual evapotranspiration, rainfall and land use. For our validation we used only those papers that covered study periods of one season to annual cycles because the accumulated water balance is the primary concern. Review papers covering shorter periods only (days, weeks) were not included in our review. Our review shows that by using remote sensing, the spatial distribution of evapotranspiration can be mapped with an overall accuracy of 95% (STD 5%) and rainfall with an overall accuracy of 82% (STD 15%). Land use can be identified with an overall accuracy of 85% (STD 7%). Hence, more scientific work is needed to improve spatial mapping of rainfall using multiple space-borne sensors. Actual evapotranspiration maps can be used with confidence in water accounting and hydrological modeling.

  17. Evidence for impairments in using static line drawings of eye gaze cues to orient visual-spatial attention in children with high functioning autism.

    PubMed

    Goldberg, Melissa C; Mostow, Allison J; Vecera, Shaun P; Larson, Jennifer C Gidley; Mostofsky, Stewart H; Mahone, E Mark; Denckla, Martha B

    2008-09-01

    We examined the ability to use static line drawings of eye gaze cues to orient visual-spatial attention in children with high functioning autism (HFA) compared to typically developing children (TD). The task was organized such that on valid trials, gaze cues were directed toward the same spatial location as the appearance of an upcoming target, while on invalid trials gaze cues were directed to an opposite location. Unlike TD children, children with HFA showed no advantage in reaction time (RT) on valid trials compared to invalid trials (i.e., no significant validity effect). The two stimulus onset asynchronies (200 ms, 700 ms) did not differentially affect these findings. The results suggest that children with HFA show impairments in utilizing static line drawings of gaze cues to orient visual-spatial attention. PMID:18074212

  18. Effect of spectral/spatial transformation on remote sensing image for NDVI-based drought detection analysis

    NASA Astrophysics Data System (ADS)

    Akbar, Fikri; Suryana, Nanna; Hussin, Burairah

    2011-10-01

    Remote sensing image have been known to be an important part for environmental analysis. Drought early warning system is one of the few example of remote sensing image applications. One of the oldest tool in remote sensing studies, NDVI is often used for drought detection. Although very essential, remote sensing image requires large storage requirement. A large image data may cause network congestion which certainly affects the aptitude of the drought detection system. An image compression may be used as an approach to this issue. However, this would lead to another issue, image quality. This article emphasize on the effect of image compression through transformation towards remote sensing image. Analysis is conducted through NDVI pixel threshold as well as other complimentary error metric method. Hybrid methods of transformation are presented here for the image transformation process. The experiments performed on test images shows that hybrid transformation is capable of reducing image data and preserving sufficient quality.

  19. Spatial navigation, episodic memory, episodic future thinking, and theory of mind in children with autism spectrum disorder: evidence for impairments in mental simulation?

    PubMed Central

    Lind, Sophie E.; Bowler, Dermot M.; Raber, Jacob

    2014-01-01

    This study explored spatial navigation alongside several other cognitive abilities that are thought to share common underlying neurocognitive mechanisms (e.g., the capacity for self-projection, scene construction, or mental simulation), and which we hypothesized may be impaired in autism spectrum disorder (ASD). Twenty intellectually high-functioning children with ASD (with a mean age of ~8 years) were compared to 20 sex, age, IQ, and language ability matched typically developing children on a series of tasks to assess spatial navigation, episodic memory, episodic future thinking (also known as episodic foresight or prospection), theory of mind (ToM), relational memory, and central coherence. This is the first study to explore these abilities concurrently within the same sample. Spatial navigation was assessed using the “memory island” task, which involves finding objects within a realistic, computer simulated, three-dimensional environment. Episodic memory and episodic future thinking were assessed using a past and future event description task. ToM was assessed using the “animations” task, in which children were asked to describe the interactions between two animated triangles. Relational memory was assessed using a recognition task involving memory for items (line drawings), patterned backgrounds, or combinations of items and backgrounds. Central coherence was assessed by exploring differences in performance across segmented and unsegmented versions of block design. Children with ASD were found to show impairments in spatial navigation, episodic memory, episodic future thinking, and central coherence, but not ToM or relational memory. Among children with ASD, spatial navigation was found to be significantly negatively related to the number of repetitive behaviors. In other words, children who showed more repetitive behaviors showed poorer spatial navigation. The theoretical and practical implications of the results are discussed. PMID:25538661

  20. Compound danshen tablet ameliorated aβ25-35-induced spatial memory impairment in mice via rescuing imbalance between cytokines and neurotrophins

    PubMed Central

    2014-01-01

    Background Compound Danshen Tablet (CDT), a Traditional Chinese Medicine, has recently been reported to improve spatial cognition in a rat model of Alzheimer’s disease. However, in vivo neuroprotective mechanism of the CDT in models of spatial memory impairment is not yet evaluated. The present study is aimed to elucidate the cellular mechanism of CDT on Aβ25-35-induced cognitive impairment in mice. Methods Mice were randomly divided into 5 groups: the control group (sham operated), the Aβ25-35 treated group, the positive drug group, and large and small dosage of the CDT groups, respectively. CDT was administered at a dose of 0.81 g/kg and 0.405 g/kg for 3 weeks. The mice in the positive drug group were treated with 0.4 mg/kg of Huperzine A, whereas the mice of the control and Aβ25-35 treated groups were administrated orally with equivalent saline. After 7 days of preventive treatment, mice were subjected to lateral ventricle injection of Aβ25-35 to establish the mice model of Alzheimer’s disease. Spatial memory impairment was evaluated by Morris water maze test. Choline acetyltransferase (ChAT) contents in hippocampus and cortex were quantified by ELISA. The levels of cytokines, receptor of activated protein kinase C1 (RACK1) and brain-derived neurotrophic factor (BDNF) in hippocampus were measured by RT-PCR and ELISA. Results The results showed that Aβ25-35 caused spatial memory impairment as demonstrated by performance in the Morris water maze test. CDT was able to confer a significant improvement in spatial memory, and protect mice from Aβ25-35-induced neurotoxicity. Additionally, CDT also inhibited the increase of TNF-α and IL-6 level, and increased the expression of choline acetyltransferase (ChAT), receptor of activated protein kinase C1 (RACK1) and brain-derived neurotrophic factor (BDNF) in brain as compared to model mice. Conclusion These findings strongly implicate that CDT may be a useful treatment against learning and memory deficits in

  1. Chronic administration of branched-chain amino acids impairs spatial memory and increases brain-derived neurotrophic factor in a rat model.

    PubMed

    Scaini, Giselli; Comim, Clarissa M; Oliveira, Giovanna M T; Pasquali, Matheus A B; Quevedo, João; Gelain, Daniel P; Moreira, José Cláudio F; Schuck, Patrícia F; Ferreira, Gustavo C; Bogo, Maurício R; Streck, Emilio L

    2013-09-01

    Maple syrup urine disease (MSUD) is a neurometabolic disorder that leads to the accumulation of branched-chain amino acids (BCAAs) and their α-keto branched-chain by-products. Because the neurotoxic mechanisms of MSUD are poorly understood, this study aimed to evaluate the effects of chronic administration of a BCAA pool (leucine, isoleucine and valine). This study examined the effects of BCAA administration on spatial memory and the levels of brain-derived neurotrophic factor (BNDF). We examined both pro-BDNF and bdnf mRNA expression levels after administration of BCAAs. Furthermore, this study examined whether antioxidant treatment prevented the alterations induced by BCAA administration. Our results demonstrated an increase in BDNF in the hippocampus and cerebral cortex, accompanied by memory impairment in spatial memory tasks. Additionally, chronic administration of BCAAs did not induce a detectable change in pro-BDNF levels. Treatment with N-acetylcysteine and deferoxamine prevented both the memory deficit and the increase in the BDNF levels induced by BCAA administration. In conclusion, these results suggest that when the brain is chronically exposed to high concentrations of BCAA (at millimolar concentrations) an increase in BDNF levels occurs. This increase in BDNF may be related to the impairment of spatial memory. In addition, we demonstrated that antioxidant treatment prevented the negative consequences related to BCAA administration, suggesting that oxidative stress might be involved in the pathophysiological mechanism(s) underlying the brain damage observed in MSUD. PMID:23109061

  2. Single fluoxetine treatment before but not after stress prevents stress-induced hippocampal long-term depression and spatial memory retrieval impairment in rats.

    PubMed

    Han, Huili; Dai, Chunfang; Dong, Zhifang

    2015-01-01

    A growing body of evidence has shown that chronic treatment with fluoxetine, a widely prescribed medication for treatment of depression, can affect synaptic plasticity in the adult central nervous system. However, it is not well understood whether acute fluoxetine influences synaptic plasticity, especially on hippocampal CA1 long-term depression (LTD), and if so, whether it subsequently impacts hippocampal-dependent spatial memory. Here, we reported that LTD facilitated by elevated-platform stress in hippocampal slices was completely prevented by fluoxetine administration (10 mg/kg, i.p.) 30 min before stress. The LTD was not, however, significantly inhibited by fluoxetine administration immediately after stress. Similarly, fluoxetine incubation (10 μM) during electrophysiological recordings also displayed no influence on the stress-facilitated LTD. In addition, behavioral results showed that a single fluoxetine treatment 30 min before but not after acute stress fully reversed the impairment of spatial memory retrieval in the Morris water maze paradigm. Taken together, these results suggest that acute fluoxetine treatment only before, but not after stress, can prevent hippocampal CA1 LTD and spatial memory retrieval impairment caused by behavioral stress in adult animals. PMID:26218751

  3. Short-term sleep deprivation disrupts the molecular composition of ionotropic glutamate receptors in entorhinal cortex and impairs the rat spatial reference memory.

    PubMed

    Xie, Meilan; Li, Chao; He, Chao; Yang, Li; Tan, Gang; Yan, Jie; Wang, Jiali; Hu, Zhian

    2016-03-01

    Numerous studies reported that sleep deprivation (SD) causes impairment in spatial cognitive performance. However, the molecular mechanisms affected by SD underlying this behavioral phenomenon remain elusive. Here, we focused on the entorhinal cortex (EC), the gateway of the hippocampus, and investigated how SD affected the subunit expression of AMPARs and NMDARs, the main ionotropic glutamategic receptors serving a pivotal role in spatial cognition. In EC, we found 4h SD remarkably reduced surface expression of GluA1, while there was an increase in the surface expression of GluA2 and GluA3. As for NMDARs, SD with short duration significantly reduced the surface expression levels of GluN1 and GluN2B without effect on the GluN2A. In parallel with the alterations in AMPARs and NMDARs, we found the 4h SD impaired rat spatial reference memory as assessed by Morris water maze task. Overall, these data indicate that brief SD differently affects the AMPAR and NMDAR subunit expressions in EC and might consequently disrupt the composition and functional properties of these receptors. PMID:26455878

  4. Sex-specific impairment and recovery of spatial learning following the end of chronic unpredictable restraint stress: Potential relevance of limbic GAD

    PubMed Central

    Ortiz, J. Bryce; Taylor, Sara B.; Hoffman, Ann N.; Campbell, Alyssa N.; Lucas, Louis R.; Conrad, Cheryl D.

    2015-01-01

    Chronic restraint stress alters hippocampal-dependent spatial learning and memory in a sex-dependent manner, impairing spatial performance in male rats and leaving intact or facilitating performance in female rats. Moreover, these stress-induced spatial memory deficits improve following post-stress recovery in males. The current study examined whether restraint administered in an unpredictable manner would eliminate these sex differences and impact a post-stress period on spatial ability and limbic glutamic acid decarboxylase (GAD65) expression. Male (n=30) and female (n=30) adult Sprague-Dawley rats were assigned to non-stressed control (Con), chronic stress (Str-Imm), or chronic stress given a post-stress recovery period (Str-Rec). Stressed rats were unpredictably restrained for 21 days using daily non-repeated combinations of physical context, duration, and time of day. Then, all rats were tested on the radial arm water maze (RAWM) for two days and given one retention trial on the third day, with brains removed 30 minutes later to assess GAD65 mRNA. In Str-Imm males, deficits occurred on day 1 of RAWM acquisition, an impairment that was not evident in the Str-Rec group. In contrast, females did not show significant outcomes following chronic stress or post-stress recovery. In males, amygdalar GAD65 expression negatively correlated with RAWM performance on day 1. In females, hippocampal CA1 GAD65 positively correlated with RAWM performance on day 1. These results demonstrate that GABAergic function may contribute to the sex differences observed following chronic stress. Furthermore, unpredictable restraint and a recovery period failed to eliminate the sex differences on spatial learning and memory. PMID:25591480

  5. Neuropeptide S ameliorates olfactory spatial memory impairment induced by scopolamine and MK801 through activation of cognate receptor-expressing neurons in the subiculum complex.

    PubMed

    Shao, Yu-Feng; Wang, Can; Xie, Jun-Fan; Kong, Xiang-Pan; Xin, Le; Dong, Chao-Yu; Li, Jing; Ren, Wen-Ting; Hou, Yi-Ping

    2016-07-01

    Our previous studies have demonstrated that neuropeptide S (NPS), via selective activation of the neurons bearing NPS receptor (NPSR) in the olfactory cortex, facilitates olfactory function. High level expression of NPSR mRNA in the subiculum complex of hippocampal formation suggests that NPS-NPSR system might be involved in the regulation of olfactory spatial memory. The present study was undertaken to investigate effects of NPS on the scopolamine- or MK801-induced impairment of olfactory spatial memory using computer-assisted 4-hole-board spatial memory test, and by monitoring Fos expression in the subiculum complex in mice. In addition, dual-immunofluorescence microscopy was employed to identify NPS-induced Fos-immunereactive (-ir) neurons that also bear NPSR. Intracerebroventricular administration of NPS (0.5 nmol) significantly increased the number of visits to switched odorants in recall trial in mice suffering from odor-discriminating inability induced by scopolamine, a selective muscarinic cholinergic receptor antagonist, or MK801, a N-methyl-D-aspartate receptor antagonist, after training trials. The improvement of olfactory spatial memory by NPS was abolished by the NPSR antagonist [D-Val(5)]NPS (40 nmol). Ex vivo c-Fos and NPSR immunohistochemistry revealed that, as compared with vehicle-treated mice, NPS markedly enhanced Fos expression in the subiculum complex encompassing the subiculum (S), presubiculum (PrS) and parasubiculum (PaS). The percentages of Fos-ir neurons that also express NPSR were 91.3, 86.5 and 90.0 % in the S, PrS and PaS, respectively. The present findings demonstrate that NPS, via selective activation of the neurons bearing NPSR in the subiculum complex, ameliorates olfactory spatial memory impairment induced by scopolamine and MK801 in mice. PMID:26323488

  6. Impaired Spatial Memory Performance in Adult Wistar Rats Exposed to Low (5-20 cGy) Doses of 1 GeV/n (56)Fe Particles.

    PubMed

    Britten, Richard A; Jewell, Jessica S; Miller, Vania D; Davis, Leslie K; Hadley, Melissa M; Wyrobek, Andrew J

    2016-03-01

    Prolonged deep space missions to planets and asteroids will expose astronauts to galactic cosmic radiation, comprised of low-linear energy transfer (LET) ionizing radiations, high-energy protons and high-Z and energy (HZE) particles, such as (56)Fe nuclei. In prior studies with rodents exposed to HZE particle radiation at doses likely to be encountered during deep space missions (<20 cGy) investigators reported impaired hippocampal-dependent neurocognitive performance and further observed substantial variation among the irradiated animals in neurocognitive impairment, ranging from no observable effects to severe impairment. These findings point to the importance of incorporating quantitative measures of interindividual variations into next generation risk assessment models of radiation risks on neurocognition. In this study, 269 male proven breeder Wistar rats were exposed to 1 GeV/n (56)Fe at doses of 0, 5, 10, 15 and 20 cGy, and tested for spatial memory performance on the Barnes maze at three months after exposure. The radiation response data were compared using changes in mean cohort performance and by the proportion of poor responders using the performance benchmark of two standard deviations below the mean value among the sham-irradiated cohort. Acute exposures to mission-relevant doses of 1 GeV/n (56)Fe reduced the mean spatial memory performance at three months after exposure (P < 0.002) and increased the proportions of poor performers, 2- to 3-fold. However, a substantial fraction of animals in all exposure cohorts showed no detectable change in performance, compared to the distribution of sham-irradiated animals. Our findings suggest that individualized metrics of susceptibility or resistance to radiation-induce changes in neurocognitive performance will be advantageous to the development of probabilistic risk assessment models for HZE-induced neurocognitive impairment. PMID:26943453

  7. CREB antisense oligodeoxynucleotide administration into the dorsal hippocampal CA3 region impairs long- but not short-term spatial memory in mice

    PubMed Central

    Florian, Cédrick; Mons, Nicole; Roullet, Pascal

    2006-01-01

    The transcription factor cAMP response-element binding protein (CREB) has a pivotal role in hippocampal synaptic plasticity and hippocampus-dependent long-term memory. We recently demonstrated that the dorsal hippocampal CA3 region is involved in memory consolidation of spatial information tested on a Morris water maze in mice. To test whether activation of CREB in the CA3 region is required for memory consolidation of spatial information, bilaterally cannulated mice were infused 18 h before the beginning of the behavioral training with antisense or control sense CREB oligodeoxynucleotides (ODNs) or buffer. Mice were then subjected to massed training in a spatial version of the water maze and tested for retention 0 or 24 h after the last training session. We showed that CREB antisense ODN-infusion in the CA3 region impaired long-term memory when tested 24 h later but had no effect on spatial acquisition or short-term memory tested immediately after behavioral training. These findings provide evidence that the regionally restricted activation of CREB in the dorsal hippocampal CA3 region is critical for the long-term memory consolidation phase of spatial learning but not for short-term memory. PMID:16882863

  8. Development of indicators of urban quality of life through very high spatial resolution remote sensing: A case study of Hanoi

    NASA Astrophysics Data System (ADS)

    Pham, Thi Thanh Hien

    In studies of urban quality of life, the information that can be extracted from satellite images is limited by image resolution and by the standard method of pixel classification. Recently, very high spatial resolution (VHSR) satellite images have allowed the development of new remote sensing application, especially for complex urban areas. Despite of the numerous advantages of the object-oriented approach for VHSR image processing, the parameters used to carry it out, especially at the object creation stage, are not very well documented. Moreover, the evaluation of urban quality of life has never considered the perception of inhabitants of the zones under study. This dissertation therefore addresses these two issues and aims 1) at testing a systematic ways of achieving the best parameters for object-oriented classification with the software Definiens and 2) at quantifying the relation between objective indicators and perceived satisfaction. Hoan Kiem district, in Hanoi, Vietnam, was chosen as our zone of interest. The image used for this study is a 0,7m spatial resolution Quickbird image. In the first part of the dissertation, we identify eight land occupation classes on the image: lakes, river, parks, groups of trees along streets, isolated trees, large road and residential blocks. Using these classes and additional cartographic information, we calculate nine quality of life indicators that correspond to two central aspects of urban life: commodity (urban services) and amenity (urban landscape). For each group of indicators, we carried out a principal components analysis to obtain non-correlated components. We then conducted a survey with eight city planning experts who live and work in the zone under study to Obtain an assessment of the satisfaction of inhabitants towards their area of residence. The weight of each component in the determination of quality of life was achieved through an ordinal regression whose independent variables are the components and the

  9. Fine-scale, multidimensional spatial patterns of forest canopy structure derived from remotely sensed and simulated datasets

    NASA Astrophysics Data System (ADS)

    Frazer, Gordon Wilson

    Forests are not simply storehouses of timber or wood fibre for human consumption and economic development. They represent structurally and ecologically rich habitat for an estimated 40 percent of the earth's extant species, and form the functional interface between the biosphere and atmosphere for some 27 percent of the earth's terrestrial surface. Forests, therefore, play a vital role in the maintenance of biodiversity and the regulation of local to global scale ecosystem processes and functions. Present strategies for conserving biodiversity in managed forests are based on the notion that maintaining the full range of structural conditions historically present in natural forests is the best approach for assuring the long-term persistence of a broad range of native species. The overarching goal of this dissertation is to contribute to the development of novel forest measurements that are relevant to organisms and ecosystems, and much needed by forest scientists and managers to recognize and retain the key elements and patterns of forest structure that are crucial for the conservation of forest biodiversity. This study focuses explicitly on fine-spatial-scale, multidimensional patterns of forest canopy structure based on the assumption that the 'canopy' is the primary focal site of complex interactions between vegetation and the physical environment. Two disparate remote sensing technologies---ground-based hemispherical (fisheye) canopy photography and airborne discrete-return LiDAR---are employed to characterize angular, vertical, and horizontal patterns of forest canopy structure. A quantitative technique is developed for precise measurements of gap fraction (P), element clumping (O), mean projection coefficient (G), and leaf area index (L) from sequences (sets) of black and white pixels extracted at specific view angles in digital fisheye photos. Results are compared with three other leading techniques and validated using well-documented simulated and real

  10. Effects of harmine, an acetylcholinesterase inhibitor, on spatial learning and memory of APP/PS1 transgenic mice and scopolamine-induced memory impairment mice.

    PubMed

    He, Dandan; Wu, Hui; Wei, Yue; Liu, Wei; Huang, Fei; Shi, Hailian; Zhang, Beibei; Wu, Xiaojun; Wang, Changhong

    2015-12-01

    Harmine, a β-carboline alkaloid present in Peganum harmala with a wide spectrum of pharmacological activities, has been shown to exert strong inhibition against acetylcholinesterase in vitro. However, whether it can rescue the impaired cognition has not been elucidated yet. In current study, we examined its effects on scopolamine-induced memory impairment mice and APP/PS1 transgenic mice, one of the models for Alzheimer's disease, using Morris Water Maze test. In addition, whether harmine could penetrate blood brain barrier, interact with and inhibit acetylcholinesterase, and activate downstream signaling network was also investigated. Our results showed that harmine (20mg/kg) administered by oral gavage for 2 weeks could effectively enhance the spatial cognition of C57BL/6 mice impaired by intraperitoneal injection of scopolamine (1mg/kg). Meanwhile, long-term consumption of harmine (20mg/kg) for 10 weeks also slightly benefited the impaired memory of APP/PS1 mice. Furthermore, harmine could pass through blood brain barrier, penetrate into the brain parenchyma shortly after oral administration, and modulate the expression of Egr-1, c-Jun and c-Fos. Molecular docking assay disclosed that harmine molecule could directly dock into the catalytic active site of acetylcholinesterase, which was partially confirmed by its in vivo inhibitory activity on acetylcholinesterase. Taken together, all these results suggested that harmine could ameliorate impaired memory by enhancement of cholinergic neurotransmission via inhibiting the activity of acetylcholinesterase, which may contribute to its clinical use in the therapy of neurological diseases characterized with acetylcholinesterase deficiency. PMID:26526348

  11. Spatial Discrimination Reversal Learning in Weanling Rats Is Impaired by Striatal Administration of an NMDA-Receptor Antagonist

    ERIC Educational Resources Information Center

    Watson, Deborah J.; Stanton, Mark E.

    2009-01-01

    The striatum plays a major role in both motor control and learning and memory, including executive function and "behavioral flexibility." Lesion, temporary inactivation, and infusion of an N-methyl-d-aspartate (NMDA)-receptor antagonist into the dorsomedial striatum (dmSTR) impair reversal learning in adult rats. Systemic administration of MK-801…

  12. Visual Spatial Attention and Speech Segmentation are Both Impaired in Preschoolers at Familial Risk for Developmental Dyslexia

    ERIC Educational Resources Information Center

    Facoetti, Andrea; Corradi, Nicola; Ruffino, Milena; Gori, Simone; Zorzi, Marco

    2010-01-01

    Phonological skills are foundational of reading acquisition and impaired phonological processing is widely assumed to characterize dyslexic individuals. However, reading by phonological decoding also requires rapid selection of sublexical orthographic units through serial attentional orienting, and recent studies have shown that visual spatial…

  13. Decreasing nicotinic receptor activity and the spatial learning impairment caused by the NMDA glutamate antagonist dizocilpine in rats

    PubMed Central

    Burke, Dennis A.; Heshmati, Pooneh; Kholdebarin, Ehsan; Levin, Edward D.

    2014-01-01

    Nicotinic systems have been shown by a variety of studies to be involved in cognitive function. Nicotinic receptors have an inherent property to become desensitized after activation. The relative role of nicotinic receptor activation vs. net receptor inactivation by desensitization in the cognitive effects of nicotinic drugs remains to be fully understood. In these studies, we tested the effects of the α7 nicotinic receptor antagonist methyllycaconitine (MLA), the α4β2 nicotinic receptor antagonist dihydro-β-erythroidine (DHβE), the nonspecific nicotinic channel blocker mecamylamine and the α4β2 nicotinic receptor desensitizing agent sazetidine-A on learning in a repeated acquisition test. Adult female Sprague-Dawley rats were trained on a repeated acquisition learning procedure in an 8-arm radial maze. MLA (1–4 mg/kg), DHβE (1–4 mg/kg), mecamylamine (0.125–0.5 mg/kg) or sazetidine-A (1 and 3 mg/kg) were administered in four different studies either alone or together with the NMDA glutamate antagonist dizocilpine (0.05 and 0.10 mg/kg). MLA significantly counteracted the learning impairment caused by dizocilpine. The overall choice accuracy impairment caused by dizocilpine was significantly attenuated by co-administration of DHβE. Low doses of the non-specific nicotinic antagonist mecamylamine also reduced dizocilpine-induced repeated acquisition impairment. Sazetidine-A reversed the accuracy impairment caused by dizocilpine. These studies provide evidence that a net decrease in nicotinic receptor activity can improve learning by attenuating learning impairment induced by NMDA glutamate blockade. This adds to evidence in cognitive tests that nicotinic antagonists can improve cognitive function. Further research characterizing the efficacy and mechanisms underlying nicotinic antagonist and desensitization induced cognitive improvement is warranted. PMID:25064338

  14. Assimilation of spatially distributed water levels into a shallow-water flood model. Part II: Use of a remote sensing image of Mosel River

    NASA Astrophysics Data System (ADS)

    Hostache, Renaud; Lai, Xijun; Monnier, Jérôme; Puech, Christian

    2010-09-01

    SummaryWith rapid flood extent mapping capabilities, Synthetic Aperture Radar (SAR) images of river inundation prove to be very relevant to operational flood management. In this context, a recently developed method provides distributed water levels from SAR images. Furthermore, in view of improving numerical flood prediction, a variational data assimilation method (4D-var) using such distributed water level has been developed in Part I of this study. This method combines an optimal sense remote sensing data (distributed water levels extracted from spatial images) and a 2D shallow water model. In the present article (Part II of the study), we also derive water levels with a ±40 cm average vertical uncertainty from a RADARSAT-1 image of a Mosel River flood event (1997, France). Assimilated in a 2D shallow water hydraulic model using the 4D-var developed method, these SAR derived spatially distributed water levels prove to be capable of enhancing model calibration. Indeed, the assimilation process can identify optimal Manning friction coefficients, at least in the river channel. Moreover, used as a guide for sensitivity analysis, remote sensing water levels allow also identifying some areas in the floodplain and the channel where Manning friction coefficients are homogeneous. This allows basing the spatial segmentation of roughness coefficient on floodplain hydraulic functioning.

  15. Semantic risk estimation of suspected minefields based on spatial relationships analysis of minefield indicators from multi-level remote sensing imagery

    NASA Astrophysics Data System (ADS)

    Chan, Jonathan Cheung-Wai; Sahli, Hichem; Wang, Yuhang

    2005-06-01

    This paper presents semantic risk estimation of suspected minefields using spatial relationships of minefield indicators extracted from multi-level remote sensing. Both satellite image and pyramidal airborne acquisitions from 900m to 30m flying heights with resolutions from 1m to 2cm resolutions are used for identification of minefield indicators. R-Histogram [1] is a quantitative representation of spatial relationship between two objects in an image. Eight spatial relationships can be generated: 1) LEFT OF, 2) RIGHT OF, 3) ABOVE, 4) BELOW, 5) NEAR, 6) FAR, 7) INSIDE, 8) OUTSIDE. R-Histogram semantics are first generated from selected indicators and metrics such as topological proximity and directional relationships are trained for soft classification of risk index (normalized as 0-1). We presented a framework of how semantic metadata generated from remote sensing images are used in risk estimation. The resultant risk index identified seven out of twelve mine accidents occurred at high risk region. More importantly, comparison with ground truth obtained after mine clearance show that three out of the four identified pattern minefields falls into the area estimated at very high risk. A parcel-based per-field risk estimation can also be easily generated to show the usefulness of the risk index.

  16. Landfills in Jiangsu province, China, and potential threats for public health: Leachate appraisal and spatial analysis using geographic information system and remote sensing

    SciTech Connect

    Yang Kun; Zhou Xiaonong Yan Weian; Hang Derong; Steinmann, Peter

    2008-12-15

    Waste disposal is of growing environmental and public health concern in China where landfilling is the predominant method of disposal. The assessment of potential health hazards posed by existing landfills requires sound information, and processing of a significant amount of spatial data. Geographical information system (GIS) and remote sensing (RS) are valuable tools for assessing health impacts due to landfills. The aims of this study were: (i) to analyze the leachate and gas emissions from landfills used for domestic waste disposal in a metropolitan area of Jiangsu province, China, (ii) to investigate remotely-sensed environmental features in close proximity to landfills, and (iii) to evaluate the compliance of their location and leachate quality with the relevant national regulations. We randomly selected five landfills in the metropolitan areas of Wuxi and Suzhou city, Jiangsu province, established a GIS database and examined whether data were in compliance with national environmental and public health regulations. The leachates of the sampled landfills contained heavy metals (Pb, As, Cr{sup 6+} and Hg) and organic compounds in concentrations considered harmful to human health. Measured methane concentrations on landfill surfaces were low. Spatial analysis of the location of landfills with regard to distance from major water bodies, sensible infrastructure and environmental conditions according to current national legislation resulted in the rejection of four of the five sites as inappropriate for landfills. Our results call for rigorous evaluation of the spatial location of landfills in China that must take into consideration environmental and public health criteria.

  17. Landfills in Jiangsu province, China, and potential threats for public health: leachate appraisal and spatial analysis using geographic information system and remote sensing.

    PubMed

    Yang, Kun; Zhou, Xiao-Nong; Yan, Wei-An; Hang, De-Rong; Steinmann, Peter

    2008-12-01

    Waste disposal is of growing environmental and public health concern in China where landfilling is the predominant method of disposal. The assessment of potential health hazards posed by existing landfills requires sound information, and processing of a significant amount of spatial data. Geographical information system (GIS) and remote sensing (RS) are valuable tools for assessing health impacts due to landfills. The aims of this study were: (i) to analyze the leachate and gas emissions from landfills used for domestic waste disposal in a metropolitan area of Jiangsu province, China, (ii) to investigate remotely-sensed environmental features in close proximity to landfills, and (iii) to evaluate the compliance of their location and leachate quality with the relevant national regulations. We randomly selected five landfills in the metropolitan areas of Wuxi and Suzhou city, Jiangsu province, established a GIS database and examined whether data were in compliance with national environmental and public health regulations. The leachates of the sampled landfills contained heavy metals (Pb, As, Cr(6+) and Hg) and organic compounds in concentrations considered harmful to human health. Measured methane concentrations on landfill surfaces were low. Spatial analysis of the location of landfills with regard to distance from major water bodies, sensible infrastructure and environmental conditions according to current national legislation resulted in the rejection of four of the five sites as inappropriate for landfills. Our results call for rigorous evaluation of the spatial location of landfills in China that must take into consideration environmental and public health criteria. PMID:18396395

  18. Modeling Spatial Patterns of Soil Respiration in Maize Fields from Vegetation and Soil Property Factors with the Use of Remote Sensing and Geographical Information System

    PubMed Central

    Huang, Ni; Wang, Li; Guo, Yiqiang; Hao, Pengyu; Niu, Zheng

    2014-01-01

    To examine the method for estimating the spatial patterns of soil respiration (Rs) in agricultural ecosystems using remote sensing and geographical information system (GIS), Rs rates were measured at 53 sites during the peak growing season of maize in three counties in North China. Through Pearson's correlation analysis, leaf area index (LAI), canopy chlorophyll content, aboveground biomass, soil organic carbon (SOC) content, and soil total nitrogen content were selected as the factors that affected spatial variability in Rs during the peak growing season of maize. The use of a structural equation modeling approach revealed that only LAI and SOC content directly affected Rs. Meanwhile, other factors indirectly affected Rs through LAI and SOC content. When three greenness vegetation indices were extracted from an optical image of an environmental and disaster mitigation satellite in China, enhanced vegetation index (EVI) showed the best correlation with LAI and was thus used as a proxy for LAI to estimate Rs at the regional scale. The spatial distribution of SOC content was obtained by extrapolating the SOC content at the plot scale based on the kriging interpolation method in GIS. When data were pooled for 38 plots, a first-order exponential analysis indicated that approximately 73% of the spatial variability in Rs during the peak growing season of maize can be explained by EVI and SOC content. Further test analysis based on independent data from 15 plots showed that the simple exponential model had acceptable accuracy in estimating the spatial patterns of Rs in maize fields on the basis of remotely sensed EVI and GIS-interpolated SOC content, with R2 of 0.69 and root-mean-square error of 0.51 µmol CO2 m−2 s−1. The conclusions from this study provide valuable information for estimates of Rs during the peak growing season of maize in three counties in North China. PMID:25157827

  19. Spatial and Temporal Distribution of Multiple Cropping Indices in the North China Plain Using a Long Remote Sensing Data Time Series.

    PubMed

    Zhao, Yan; Bai, Linyan; Feng, Jianzhong; Lin, Xiaosong; Wang, Li; Xu, Lijun; Ran, Qiyun; Wang, Kui

    2016-01-01

    Multiple cropping provides China with a very important system of intensive cultivation, and can effectively enhance the efficiency of farmland use while improving regional food production and security. A multiple cropping index (MCI), which represents the intensity of multiple cropping and reflects the effects of climate change on agricultural production and cropping systems, often serves as a useful parameter. Therefore, monitoring the dynamic changes in the MCI of farmland over a large area using remote sensing data is essential. For this purpose, nearly 30 years of MCIs related to dry land in the North China Plain (NCP) were efficiently extracted from remotely sensed leaf area index (LAI) data from the Global LAnd Surface Satellite (GLASS). Next, the characteristics of the spatial-temporal change in MCI were analyzed. First, 2162 typical arable sample sites were selected based on a gridded spatial sampling strategy, and then the LAI information was extracted from the samples. Second, the Savizky-Golay filter was used to smooth the LAI time-series data of the samples, and then the MCIs of the samples were obtained using a second-order difference algorithm. Finally, the geo-statistical Kriging method was employed to map the spatial distribution of the MCIs and to obtain a time-series dataset of the MCIs of dry land over the NCP. The results showed that all of the MCIs in the NCP showed an increasing trend over the entire study period and increased most rapidly from 1982 to 2002. Spatially, MCIs decreased from south to north; also, high MCIs were mainly concentrated in the relatively flat areas. In addition, the partial spatial changes of MCIs had clear geographical characteristics, with the largest change in Henan Province. PMID:27104536

  20. Modeling spatial patterns of soil respiration in maize fields from vegetation and soil property factors with the use of remote sensing and geographical information system.

    PubMed

    Huang, Ni; Wang, Li; Guo, Yiqiang; Hao, Pengyu; Niu, Zheng

    2014-01-01

    To examine the method for estimating the spatial patterns of soil respiration (Rs) in agricultural ecosystems using remote sensing and geographical information system (GIS), Rs rates were measured at 53 sites during the peak growing season of maize in three counties in North China. Through Pearson's correlation analysis, leaf area index (LAI), canopy chlorophyll content, aboveground biomass, soil organic carbon (SOC) content, and soil total nitrogen content were selected as the factors that affected spatial variability in Rs during the peak growing season of maize. The use of a structural equation modeling approach revealed that only LAI and SOC content directly affected Rs. Meanwhile, other factors indirectly affected Rs through LAI and SOC content. When three greenness vegetation indices were extracted from an optical image of an environmental and disaster mitigation satellite in China, enhanced vegetation index (EVI) showed the best correlation with LAI and was thus used as a proxy for LAI to estimate Rs at the regional scale. The spatial distribution of SOC content was obtained by extrapolating the SOC content at the plot scale based on the kriging interpolation method in GIS. When data were pooled for 38 plots, a first-order exponential analysis indicated that approximately 73% of the spatial variability in Rs during the peak growing season of maize can be explained by EVI and SOC content. Further test analysis based on independent data from 15 plots showed that the simple exponential model had acceptable accuracy in estimating the spatial patterns of Rs in maize fields on the basis of remotely sensed EVI and GIS-interpolated SOC content, with R2 of 0.69 and root-mean-square error of 0.51 µmol CO2 m(-2) s(-1). The conclusions from this study provide valuable information for estimates of Rs during the peak growing season of maize in three counties in North China. PMID:25157827

  1. Spatial and Temporal Distribution of Multiple Cropping Indices in the North China Plain Using a Long Remote Sensing Data Time Series

    PubMed Central

    Zhao, Yan; Bai, Linyan; Feng, Jianzhong; Lin, Xiaosong; Wang, Li; Xu, Lijun; Ran, Qiyun; Wang, Kui

    2016-01-01

    Multiple cropping provides China with a very important system of intensive cultivation, and can effectively enhance the efficiency of farmland use while improving regional food production and security. A multiple cropping index (MCI), which represents the intensity of multiple cropping and reflects the effects of climate change on agricultural production and cropping systems, often serves as a useful parameter. Therefore, monitoring the dynamic changes in the MCI of farmland over a large area using remote sensing data is essential. For this purpose, nearly 30 years of MCIs related to dry land in the North China Plain (NCP) were efficiently extracted from remotely sensed leaf area index (LAI) data from the Global LAnd Surface Satellite (GLASS). Next, the characteristics of the spatial-temporal change in MCI were analyzed. First, 2162 typical arable sample sites were selected based on a gridded spatial sampling strategy, and then the LAI information was extracted from the samples. Second, the Savizky-Golay filter was used to smooth the LAI time-series data of the samples, and then the MCIs of the samples were obtained using a second-order difference algorithm. Finally, the geo-statistical Kriging method was employed to map the spatial distribution of the MCIs and to obtain a time-series dataset of the MCIs of dry land over the NCP. The results showed that all of the MCIs in the NCP showed an increasing trend over the entire study period and increased most rapidly from 1982 to 2002. Spatially, MCIs decreased from south to north; also, high MCIs were mainly concentrated in the relatively flat areas. In addition, the partial spatial changes of MCIs had clear geographical characteristics, with the largest change in Henan Province. PMID:27104536

  2. Remote sensing to detect the movement of wheat curl mites through the spatial spread of virus symptoms, and identification of thrips as predators of wheat curl mites

    NASA Astrophysics Data System (ADS)

    Stilwell, Abby R.

    The wheat curl mite (WCM), Aceria tosichella Keifer, transmits three viruses to winter wheat: wheat streak mosaic virus, High Plains virus, and Triticum mosaic virus. This virus complex causes yellowing of the foliage and stunting of plants. WCMs disperse by wind, and an increased understanding of mite movement and subsequent virus spread is necessary in determining the risk of serious virus infections in winter wheat. These risk parameters will help growers make better decisions regarding WCM management. The objectives of this study were to evaluate the capabilities of remote sensing to identify virus infected plants and to establish the potential of using remote sensing to track virus spread and consequently, mite movement. Although the WCM is small and very hard to track, the viruses it vectors produce symptoms that can be detected with remote sensing. Field plots of simulated volunteer wheat were established between 2006 and 2009, infested with WCMs, and spread mites and virus into adjacent winter wheat. The virus gradients created by WCM movement allowed for the measurement of mite movement potential with both proximal and aerial remote sensing instruments. The ability to detect WCM-vectored viruses with remote sensing was investigated by comparing vegetation indices calculated from proximal remote sensing data to ground truth data obtained in the field. Of the ten vegetation indices tested, the red edge position (REP) index had the best relationship with ground truth data. The spatial spread of virus from WCM source plots was modeled with cokriging. Virus symptoms predicted by cokriging occurred in an oval pattern displaced to the southeast. Data from the spatial spread in small plots of this study were used to estimate the potential sphere of influence for volunteer wheat fields. The impact of thrips on WCM populations was investigated by a series of greenhouse, field, and observational studies. WCM populations in winter wheat increased more slowly when

  3. Enhanced Long-Term and Impaired Short-Term Spatial Memory in GluA1 AMPA Receptor Subunit Knockout Mice: Evidence for a Dual-Process Memory Model

    ERIC Educational Resources Information Center

    Sanderson, David J.; Good, Mark A.; Skelton, Kathryn; Sprengel, Rolf; Seeburg, Peter H.; Rawlins, J. Nicholas P.; Bannerman, David M.

    2009-01-01

    The GluA1 AMPA receptor subunit is a key mediator of hippocampal synaptic plasticity and is especially important for a rapidly-induced, short-lasting form of potentiation. GluA1 gene deletion impairs hippocampus-dependent, spatial working memory, but spares hippocampus-dependent spatial reference memory. These findings may reflect the necessity of…

  4. Inhibition deficit in the spatial tendency of the response in multiple-domain amnestic mild cognitive impairment. An event-related potential study

    PubMed Central

    Cespón, Jesús; Galdo-Álvarez, Santiago; Díaz, Fernando

    2015-01-01

    Longitudinal studies have shown that a high percentage of people with amnestic mild cognitive impairment (MCI) develop Alzheimer’s disease (AD). Prodromal AD is known to involve deficits in executive control processes. In the present study, we examined such deficits by recording EEG in 13 single-domain amnestic MCI (sdaMCI), 12 multiple-domain amnestic MCI (mdaMCI) and 18 healthy elderly (control group, CG) participants while they performed a Simon task. The Simon task demands deployment of executive processes because participants have to respond to non-spatial features of a lateralized stimulus and inhibit the more automatic spatial tendency of the response. We specifically focused on the negativity central contralateral (N2cc), an event-related potential (ERP) component related to brain activity that prevents the cross-talk between direction of spatial attention and manual response preparation. The reaction time (RT) was not significantly different among the three groups of participants. The percentage of errors (PE) was higher in mdaMCI than in CG and sdaMCI participants. In addition, N2cc latency was delayed in mdaMCI (i.e., delayed implementation of mechanisms for controlling the spatial tendency of the response). The N2cc latency clearly distinguished among mdaMCI and CG/sdaMCI participants (area under curve: 0.91). Longer N2cc was therefore associated with executive control deficits, which suggests that N2cc latency is a correlate of mdaMCI. PMID:25999853

  5. Spatial distribution and seasonal variability of chlorophyll-a concentration in the Azov Sea turbid waters by means of remote sensing and continuous fluorescence measurements

    NASA Astrophysics Data System (ADS)

    Saprygin, V. V.

    2011-12-01

    The goal of this study was to apply continuous fluorometric and remote estimation of chlorophyll-a concentration (Cchl) techniques to complex turbid waters of Azov Sea and explore Cchl temporal variation and spatial pattern. Azov Sea is the shallowest sea in the world with maximum depth below 15 m. Its maximum salinity is about 14%; total suspended solids and chlorophyll-a concentrations reach 120 [tex]g m^{-3}[/tex] and 100 [tex]mg m^{-3}[/tex] respectively in Taganrog Bay, daily production varies up to 3.5 [tex]gC_{org} m^{-3}[/tex]. Chlorophyll-a concentrations were measured in 2008-2010 year-round spectrophotometrically, 446 water samples were taken to calibrate fluorometerical and remote sensing data. The highest recorded concentration was 149.3, the lowest - 0.3 [tex]mg m^{-3}[/tex]. Continuous-flow fluorometer was applied in the course of 3 expeditions to Taganrog Bay to measure chlorophyll-a fluorescence (Fchl) each 30 meters along the ship path. Two-cuvette fluorometer was used to discount the influence of dissolved organic matter. Fchl measurements were calibrated and Cchl profiles derieved to estimate Cchl spatial heterogeneity in close scale. Fchl measurements were also made during moorings each 6 seconds to estimate temporal Cchl variability. Recently published algorithm based on reflectance in the red and the near-infrared (NIR) spectral regions was applied to MERIS data for the remote estimation of Cchl. Taking in account fluorometric Cchl spatial heterogeneity estimation, the algorithm for culling the outliers in Cchl fields derived from satellite data was developed. 74 images were processed to Cchl maps and then averaged monthly. Consequently, Cchl spatial distribution and seasonal variability were studied. Spectrophotometric, flourumetric measurements and values obtained by NIR-red algorithm showed strong correlation in turbid Case II waters of Azov Sea. Fluorometric and remote measurements showed high Cchl variations in short and long terms

  6. Transfer of three transcription factors via a lentiviral vector ameliorates spatial learning and memory impairment in a mouse model of Alzheimer's disease.

    PubMed

    Chen, Pin; Yan, Qing; Wang, Songtao; Wang, Cunzu; Zhao, Peng

    2016-08-01

    Alzheimer's disease (AD) is an irreversible and progressive neurodegenerative disorder with observable memory impairment. The present study was performed to evaluate the beneficial effects of lentiviral vector-mediated overexpression of a combination of three transcription regulators, ABN (Ascl1, Brn2 and Ngn2), on learning and memory loss in a mouse model of AD. The AD model was established by injecting Aβ1-42 bilaterally into the mouse hippocampus. Lentiviral ABN was delivered bilaterally into the hippocampus of mice. Animals injected with LV-ABN showed significantly improved spatial learning and memory in the water maze test. Additionally, antibody array analysis indicated that intrahippocampal LV-ABN delivery significantly altered the expression levels of some proteins that were identified as inflammatory factors or neuroprotective and growth factors. In conclusion, our data suggest that LV-ABN delivery can ameliorate spatial learning and memory impairment in an AD mouse model, and the beneficial effect of ABN gene treatment could be linked to inhibition of the neuroinflammatory response and enhancement of neuroprotection and neurogenesis. Thus, these findings indicate that lentiviral ABN gene delivery has potential therapeutic applications for AD. PMID:27102892

  7. Prevalence of pure versus mixed snow cover pixels across spatial resolutions in alpine environments: implications for binary and fractional remote sensing approaches

    USGS Publications Warehouse

    Selkowitz, David J.; Forster, Richard; Caldwell, Megan K.

    2014-01-01

    Remote sensing of snow-covered area (SCA) can be binary (indicating the presence/absence of snow cover at each pixel) or fractional (indicating the fraction of each pixel covered by snow). Fractional SCA mapping provides more information than binary SCA, but is more difficult to implement and may not be feasible with all types of remote sensing data. The utility of fractional SCA mapping relative to binary SCA mapping varies with the intended application as well as by spatial resolution, temporal resolution and period of interest, and climate. We quantified the frequency of occurrence of partially snow-covered (mixed) pixels at spatial resolutions between 1 m and 500 m over five dates at two study areas in the western U.S., using 0.5 m binary SCA maps derived from high spatial resolution imagery aggregated to fractional SCA at coarser spatial resolutions. In addition, we used in situ monitoring to estimate the frequency of partially snow-covered conditions for the period September 2013–August 2014 at 10 60-m grid cell footprints at two study areas with continental snow climates. Results from the image analysis indicate that at 40 m, slightly above the nominal spatial resolution of Landsat, mixed pixels accounted for 25%–93% of total pixels, while at 500 m, the nominal spatial resolution of MODIS bands used for snow cover mapping, mixed pixels accounted for 67%–100% of total pixels. Mixed pixels occurred more commonly at the continental snow climate site than at the maritime snow climate site. The in situ data indicate that some snow cover was present between 186 and 303 days, and partial snow cover conditions occurred on 10%–98% of days with snow cover. Four sites remained partially snow-free throughout most of the winter and spring, while six sites were entirely snow covered throughout most or all of the winter and spring. Within 60 m grid cells, the late spring/summer transition from snow-covered to snow-free conditions lasted 17–56 days and averaged 37

  8. Spatial and temporal dynamic of surface water and vegetation dynamic using remotely sensed data in the Murray -Darling Basin, Australia

    NASA Astrophysics Data System (ADS)

    Tulbure, M. G.; Kingsford, R.; Broich, M.

    2012-12-01

    Australia is the driest inhabited continent and river systems have highly variable flows in space and time. The Murray-Darling Basin (MDB), a catchment covering 14% of the continent contains the nation's largest rivers and important groundwater systems. The basin has highly variable rainfall patterns in space and time and the vast majority of rainfall is lost to evapotranspiration with only 4% becoming runoff. The basin is home to several wetlands of high hydrological and ecological value with a number of them being recognised as wetlands of international importance. The basin produces more than a third of Australia's food supply, making it the most important agricultural area in the country. However, variation in surface and ground water availability exacerbated by a long period of drought, combined with high water demands for irrigation and in several major cities, and the need for water to maintain ecosystem health in the floodplains have led to the need of managing water resources in an integrated fashion. Several dams have been constructed in the basin, which store water during wet periods which is released during dry periods as environmental flows. Assessment of water resources and understanding of the effectiveness of environmental flows requires knowledge of 1) long term trends in occurrence and extent of surface water, 2) what is the vegetation response to flooding and 3) whether water reached target vegetation communities. However, such information does not exist at the basin level. Satellite remote sensing is the only viable way for synoptically mapping and monitoring the extent and dynamic of flooding and vegetation response to flooding. Moreover, recent La Nina -induced, extreme flooding broke a decade long of drought and made 2010 the wettest calendar year on record in the MDB and across vast areas of Australia. This represents a unique opportunity to develop predictive models relating flow regime to vegetation response and identify trends over long

  9. Impairment of Rat Spatial Learning and Memory in a New Model of Cold Water-Induced Chronic Hypothermia: Implication for Alzheimer's Disease.

    PubMed

    Ahmadian-Attari, Mohammad Mahdi; Dargahi, Leila; Mosaddegh, Mahmoud; Kamalinejad, Mohammad; Khallaghi, Behzad; Noorbala, Fatemeh; Ahmadiani, Abolhassan

    2015-08-01

    Alzheimer's disease (AD) is a primary neurodegenerative disorder associated with progressive memory impairment. Recent studies suggest that hypothermia may contribute to the development and exacerbation of AD. The aim of this study was to investigate the role of chronic hypothermia on spatial learning and memory performance as well as brain immunohistochemical (IHC) and molecular changes. Four groups of male rats were placed in cold water (3.5 ± 0.5 °C) once a day for 1, 3, 6, and 14 days, four other groups were placed in warm water (32 °C) as the control groups to eliminate the effect of swimming stress, and one more group which comprised intact animals that were kept in a normothermic situation and had no swimming stress. Twenty-four hours after the last intervention, spatial learning and memory were assessed, using the modified Morris water maze. After the behavioral test, the rats' brains were removed for IHC and Western blotting. The results showed that memory retrieval is impaired after 14 days of cold water-induced hypothermia (CWH) (P < 0.05). IHC showed the formation of beta-amyloid plaques after a 14-day CWH. The molecular changes demonstrated that a 14-day CWH induces tau hyperphosphorylation, apoptosis, and reduces COX-II expression. Therefore, chronic CWH, independent of forced swimming stress, impairs learning and memory through molecular mechanisms similar to those of AD. In conclusion, CWH may serve as an important model to assess the role of hypothermia in AD pathogenesis. PMID:25782579

  10. Chronic copper exposure causes spatial memory impairment, selective loss of hippocampal synaptic proteins, and activation of PKR/eIF2α pathway in mice.

    PubMed

    Ma, Quan; Ying, Ming; Sui, Xiaojing; Zhang, Huimin; Huang, Haiyan; Yang, Linqing; Huang, Xinfeng; Zhuang, Zhixiong; Liu, Jianjun; Yang, Xifei

    2015-01-01

    Copper is an essential element for human growth and development; however, excessive intake of copper could contribute to neurotoxicity. Here we show that chronic exposure to copper in drinking water impaired spatial memory with simultaneous selective loss of hippocampal pre-synaptic protein synapsin 1, and post-synaptic density protein (PSD)-93/95 in mice. Copper exposure was shown to elevate the levels of nitrotyrosine and 8-hydroxydeoxyguanosine (8-OHdG) in hippocampus, two markers of oxidative stress. Concurrently, we also found that copper exposure activated double stranded RNA-dependent protein kinase (PKR) as evidenced by increased ratio of phosphorylated PKR at Thr451 and total PKR and increased the phosphorylation of its downstream signaling molecule eukaryotic initiation factor 2α (eIF2α) at Ser51 in hippocampus. Consistent with activation of PKR/eIF2α signaling pathway which was shown to mediate synaptic deficit and cognitive impairment, the levels of activating transcription factor 4 (ATF-4), a downstream signaling molecule of eIF2α and a repressor of CREB-mediated gene expression, were significantly increased, while the activity of cAMP response elements binding protein (CREB) was inactivated as suggested by decreased phosphorylation of CREB at Ser133 by copper exposure. In addition, the expression of the pro-apoptotic target molecule C/EBP homology protein (CHOP) of ATF-4 was upregulated and hippocampal neuronal apoptosis was induced by copper exposure. Taken together, we propose that chronic copper exposure might cause spatial memory impairment, selective loss of synaptic proteins, and neuronal apoptosis through the mechanisms involving activation of PKR/eIF2α signaling pathway. PMID:25159668

  11. Exendin-4, a glucagon-like peptide 1 receptor agonist, protects against amyloid-β peptide-induced impairment of spatial learning and memory in rats.

    PubMed

    Jia, Xiao-Tao; Ye-Tian; Yuan-Li; Zhang, Ge-Juan; Liu, Zhi-Qin; Di, Zheng-Li; Ying, Xiao-Ping; Fang, Yan; Song, Er-Fei; Qi, Jin-Shun; Pan, Yan-Fang

    2016-05-15

    Type 2 diabetes mellitus (T2DM) and Alzheimer's disease (AD) share specific molecular mechanisms, and agents with proven efficacy in one may be useful against the other. The glucagon-like peptide-1 (GLP-1) receptor agonist exendin-4 has similar properties to GLP-1 and is currently in clinical use for T2DM treatment. Thus, this study was designed to characterize the effects of exendin-4 on the impairment of learning and memory induced by amyloid protein (Aβ) and its probable molecular underlying mechanisms. The results showed that (1) intracerebroventricular (i.c.v.) injection of Aβ1-42 resulted in a significant decline of spatial learning and memory of rats in water maze tests; (2) pretreatment with exendin-4 effectively and dose-dependently protected against the Aβ1-42-induced impairment of spatial learning and memory; (3) exendin-4 treatment significantly decreased the expression of Bax and cleaved caspase-3 and increased the expression of Bcl2 in Aβ1-42-induced Alzheimer's rats. The vision and swimming speed of the rats among all groups in the visible platform tests did not show any difference. These findings indicate that systemic pretreatment with exendin-4 can effectively prevent the behavioral impairment induced by neurotoxic Aβ1-42, and the underlying protective mechanism of exendin-4 may be involved in the Bcl2, Bax and caspase-3 pathways. Thus, the application of exendin-4 or the activation of its signaling pathways may be a promising strategy to ameliorate the degenerative processes observed in AD. PMID:26992957

  12. Spatial and functional characterization, identification and assessment of isolated wetlands in Alachua County, Florida, USA - GIS and remote sensing techniques

    EPA Science Inventory

    In this study, Geographic Information Systems (GIS) and remote sensing mapping techniques were developed to identify the locations of isolated wetlands in Alachua County, FL, a 2510 sq km area in north-central Florida with diverse geology and numerous isolated wetlands. The resul...

  13. ANALYZING THE CONSEQUENCES OF ENVIRONMENTAL SPATIAL PATTERNS ON ENVIRONMENTAL RESOURCES: THE USE OF LANDSCAPE METRICS GENERATED FROM REMOTE SENSING DATA

    EPA Science Inventory

    A number of existing and new remote sensing data provide images of areas ranging from small communities to continents. These images provide views on a wide range of physical features in the landscape, including vegetation, road infrastructure, urban areas, geology, soils, and wa...

  14. Improved capabilities of the Chinese high-resolution remote sensing satellite GF-1 for monitoring suspended particulate matter (SPM) in inland waters: Radiometric and spatial considerations

    NASA Astrophysics Data System (ADS)

    Li, Jian; Chen, Xiaoling; Tian, Liqiao; Huang, Jue; Feng, Lian

    2015-08-01

    Dominated by high dynamic and small-scale variability, remote sensing of inland or coastal waters is frequently impended by insufficient spatial resolutions from conventional ocean color sensors. With the urgent need and the rapid progress in high-resolution earth observation systems (HR), it is critical to assess the capabilities of HR in inland water monitoring. In this study, the radiometric and spatial performance of the Chinese high-resolution GF-1 Wide Field Imager (WFI) data for water quality monitoring were evaluated in term of the signal-to-noise ratio (SNR), sensitivity to suspended particulate matter (SPM) variations and spatial depiction ability. The SNR was statistically estimated from variable moving window method, and the radiometric sensitivity was simulated using the Moderate Resolution Atmospheric Transmission (MODTRAN) under varied surface and atmospheric conditions. Results indicated that both the SNR and the radiometric sensitivity of the GF-1 WFI were enhanced by 3-5 times than its predecessor (Chinese HJ-1 CCD) or Landsat 7 Enhanced Thematic Mapper Plus (ETM+), and were comparable to Landsat 8 Operational Land Imager (OLI) and Moderate Resolution Imaging Spectroradiometer (MODIS) medium-resolution bands (250 and 500 m), which have been extensively applied in inland water environment monitoring. Cross comparisons demonstrated high consistency of the spatial distribution and concentration of SPM maps between GF-1 WFI and Landsat 8 OLI. Furthermore, more than 75% of the spatial variations in high turbid waters were resolved from GF-1 WFI data, whereas the ability dropped to 40% when the spatial resolution was degraded to 250 m (MODIS-like sensors). Overall, GF-1 WFI is extraordinarily promising with an enhanced SNR, an increased spectral sensitivity to SPM variations and an advanced spatial resolution. With the ongoing plans of the successive GF series (2-7), the findings would serve as a reference for forthcoming applications, and are critical

  15. Environmental impacts of land use and land cover change in the Zhujiang Delta, China: An analysis using an integrated GIS, remote sensing, and spatial modeling approach

    NASA Astrophysics Data System (ADS)

    Weng, Qihao

    This dissertation attempts to apply an integrated approach of remote sensing, GIS, and spatial modeling for environmental studies. The feasibility, advantages, and disadvantages of this integrated approach are investigated through land use and land cover change modeling, environmental impact analysis, and stochastic analysis. By applying this approach to the Zhujiang Delta, this dissertation also attempts to examine the environmental implications of China's economic reform policies. This study finds that the integration among remote sensing, GIS, and spatial modeling is necessary and effective for solving many environmental problems. Integration by exchanging data files among these three elements is feasible in spite of its time-consuming and error-prone nature. Satellite remote sensing collects multispectral, multiresolution, and multitemporal data, and turns them into information valuable for environmental studies. GIS technology provides a flexible environment for entering, analyzing, and displaying digital data from various sources, and can incorporate socioeconomic data necessary for environmental problem solving. However, GIS needs to be further integrated with various spatial modeling techniques, because the current generation of GIS lacks the necessary predictive and analytical capabilities. The case study in the Zhujiang Delta examines its land use and land cover changes and environmental impacts between 1989 and 1997. Results show, first, that urban/built-up areas and horticulture farms have increased, while cropland has decreased. These changes are related to industrial and agricultural development as well as population growth during the period. The spatial process of urban expansion shows an intimate relationship with the distance from major roads and from the geometric center of a city. Second, urban land development tends to bring down greenness, raise surface radiant temperatures, and increase surface runoff. In contrast, horticulture farms promote

  16. Spatial Resolution Effects of Remote Sensing Informed Soil Nutrient Models Based on Landsat 8, RapidEye, WorldView-2 and GeoEye-1 Images

    NASA Astrophysics Data System (ADS)

    Xu, Y.; Grunwald, S.; Smith, S. E.; Abd-Elrahman, A.; Clingensmith, C. M.; Wani, S.

    2015-12-01

    Soil nutrient storage is essential and important to maintain food security and soil security in smallholder farm settings. The objective of this research was to analyze the spatial resolution effects of different remote sensing images on soil prediction models in Kothapally, India. We utilized Bayesian kriging (BK) to characterize the spatial pattern of total nitrogen (TN) and exchangeable potassium (Kex) in the topsoil (0-15 cm) at different spatial resolutions by incorporating spectral indices from Landsat 8 (30m), RapidEye (5m) and WorldView-2/GeoEye-1 images (2m). The band ratio of red to green, red to blue and green to blue, Crust Index and Atmospherically Resistant Vegetation Index from multiple images generally had high linear correlations with TN and Kex. The BK model of TN based on WorldView-2 and GeoEye-1 attained the highest model fit (R2=0.41) and lowest prediction error (RMSE=171.35 mg kg-1) compared with the BK models of TN based on Landsat 8 (R2=0.30; RMSE=182.26 mg kg-1) and RapidEye (R2=0.28; RMSE=183.52 mg kg-1). The BK model of Kex based on Landsat 8 had the highest model fit (R2=0.55) and the second lowest prediction error (RMSE=79.57 mg kg-1) compared with the BK models of Kex based on WorldView-2 and GeoEye-1 (R2=0.52; RMSE=79.42 mg kg-1) and RapidEye (R2=0.47; RMSE=83.91 mg kg-1). The lowest prediction fit and highest prediction error of soil TN and Kex models based on RapidEye suggest that the effect of fine spatial remote sensing spectral data inputs do not always lead to an increase of model fit. Soil maps based on WorldView-2 and GeoEye-1 have significant advantages in characterizing the variation of soil TN and Kex spatial pattern in smallholder farm settings compared with coarser maps. This research suggests that Digital Soil Mapping utilizing remote sensing spectral data from WorldView-2 and GeoEye-1 has high potential to be widely applied in smallholder farm settings and help smallholder farmers manage their soils and attain soil

  17. Impairments of spatial learning and memory following intrahippocampal injection in rats of 3-mercaptopropionic acid-modified CdTe quantum dots and molecular mechanisms

    PubMed Central

    Wu, Tianshu; He, Keyu; Ang, Shengjun; Ying, Jiali; Zhang, Shihan; Zhang, Ting; Xue, Yuying; Tang, Meng

    2016-01-01

    With the rapid development of nanotechnology, quantum dots (QDs) as advanced nanotechnology products have been widely used in neuroscience, including basic neurological studies and diagnosis or therapy for neurological disorders, due to their superior optical properties. In recent years, there has been intense concern regarding the toxicity of QDs, with a growing number of studies. However, knowledge of neurotoxic consequences of QDs applied in living organisms is lagging behind their development, even if several studies have attempted to evaluate the toxicity of QDs on neural cells. The aim of this study was to evaluate the adverse effects of intrahippocampal injection in rats of 3-mercaptopropionic acid (MPA)-modified CdTe QDs and underlying mechanisms. First of all, we observed impairments in learning efficiency and spatial memory in the MPA-modified CdTe QD-treated rats by using open-field and Y-maze tests, which could be attributed to pathological changes and disruption of ultrastructure of neurons and synapses in the hippocampus. In order to find the mechanisms causing these effects, transcriptome sequencing (RNA-seq), an advanced technology, was used to gain the potentially molecular targets of MPA-modified CdTe QDs. According to ample data from RNA-seq, we chose the signaling pathways of PI3K–Akt and MPAK–ERK to do a thorough investigation, because they play important roles in synaptic plasticity, long-term potentiation, and spatial memory. The data demonstrated that phosphorylated Akt (p-Akt), p-ERK1/2, and c-FOS signal transductions in the hippocampus of rats were involved in the mechanism underlying spatial learning and memory impairments caused by 3.5 nm MPA-modified CdTe QDs. PMID:27358562

  18. Impairments of spatial learning and memory following intrahippocampal injection in rats of 3-mercaptopropionic acid-modified CdTe quantum dots and molecular mechanisms.

    PubMed

    Wu, Tianshu; He, Keyu; Ang, Shengjun; Ying, Jiali; Zhang, Shihan; Zhang, Ting; Xue, Yuying; Tang, Meng

    2016-01-01

    With the rapid development of nanotechnology, quantum dots (QDs) as advanced nanotechnology products have been widely used in neuroscience, including basic neurological studies and diagnosis or therapy for neurological disorders, due to their superior optical properties. In recent years, there has been intense concern regarding the toxicity of QDs, with a growing number of studies. However, knowledge of neurotoxic consequences of QDs applied in living organisms is lagging behind their development, even if several studies have attempted to evaluate the toxicity of QDs on neural cells. The aim of this study was to evaluate the adverse effects of intrahippocampal injection in rats of 3-mercaptopropionic acid (MPA)-modified CdTe QDs and underlying mechanisms. First of all, we observed impairments in learning efficiency and spatial memory in the MPA-modified CdTe QD-treated rats by using open-field and Y-maze tests, which could be attributed to pathological changes and disruption of ultrastructure of neurons and synapses in the hippocampus. In order to find the mechanisms causing these effects, transcriptome sequencing (RNA-seq), an advanced technology, was used to gain the potentially molecular targets of MPA-modified CdTe QDs. According to ample data from RNA-seq, we chose the signaling pathways of PI3K-Akt and MPAK-ERK to do a thorough investigation, because they play important roles in synaptic plasticity, long-term potentiation, and spatial memory. The data demonstrated that phosphorylated Akt (p-Akt), p-ERK1/2, and c-FOS signal transductions in the hippocampus of rats were involved in the mechanism underlying spatial learning and memory impairments caused by 3.5 nm MPA-modified CdTe QDs. PMID:27358562

  19. Mental "Space" Travel: Damage to Posterior Parietal Cortex Prevents Egocentric Navigation and Reexperiencing of Remote Spatial Memories

    ERIC Educational Resources Information Center

    Ciaramelli, Elisa; Rosenbaum, R. Shayna; Solcz, Stephanie; Levine, Brian; Moscovitch, Morris

    2010-01-01

    The ability to navigate in a familiar environment depends on both an intact mental representation of allocentric spatial information and the integrity of systems supporting complementary egocentric representations. Although the hippocampus has been implicated in learning new allocentric spatial information, converging evidence suggests that the…

  20. Imidacloprid toxicity impairs spatial memory of echolocation bats through neural apoptosis in hippocampal CA1 and medial entorhinal cortex areas.

    PubMed

    Hsiao, Chun-Jen; Lin, Ching-Lung; Lin, Tian-Yu; Wang, Sheue-Er; Wu, Chung-Hsin

    2016-04-13

    It has been reported that the decimation of honey bees was because of pesticides of imidacloprid. The imidacloprid is a wildly used neonicotinoid insecticide. However, whether imidacloprid toxicity interferes with the spatial memory of echolocation bats is still unclear. Thus, we compared the spatial memory of Formosan leaf-nosed bats, Hipposideros terasensis, before and after chronic treatment with a low dose of imidacloprid. We observed that stereotyped flight patterns of echolocation bats that received chronic imidacloprid treatment were quite different from their originally learned paths. We further found that neural apoptosis in hippocampal CA1 and medial entorhinal cortex areas of echolocation bats that received imidacloprid treatment was significantly enhanced in comparison with echolocation bats that received sham treatment. Thus, we suggest that imidacloprid toxicity may interfere with the spatial memory of echolocation bats through neural apoptosis in hippocampal CA1 and medial entorhinal cortex areas. The results provide direct evidence that pesticide toxicity causes a spatial memory disorder in echolocation bats. This implies that agricultural pesticides may pose severe threats to the survival of echolocation bats. PMID:26966783

  1. Daily Access to Sucrose Impairs Aspects of Spatial Memory Tasks Reliant on Pattern Separation and Neural Proliferation in Rats

    ERIC Educational Resources Information Center

    Reichelt, Amy C.; Morris, Margaret J.; Westbrook, Reginald Frederick

    2016-01-01

    High sugar diets reduce hippocampal neurogenesis, which is required for minimizing interference between memories, a process that involves "pattern separation." We provided rats with 2 h daily access to a sucrose solution for 28 d and assessed their performance on a spatial memory task. Sucrose consuming rats discriminated between objects…

  2. Dorsolateral Striatal Lesions Impair Navigation Based on Landmark-Goal Vectors but Facilitate Spatial Learning Based on a "Cognitive Map"

    ERIC Educational Resources Information Center

    Kosaki, Yutaka; Poulter, Steven L.; Austen, Joe M.; McGregor, Anthony

    2015-01-01

    In three experiments, the nature of the interaction between multiple memory systems in rats solving a variation of a spatial task in the water maze was investigated. Throughout training rats were able to find a submerged platform at a fixed distance and direction from an intramaze landmark by learning a landmark-goal vector. Extramaze cues were…

  3. Remote Sensing-Based Detection and Spatial Pattern Analysis for Geo-Ecological Niche Modeling of Tillandsia SPP. In the Atacama, Chile

    NASA Astrophysics Data System (ADS)

    Wolf, N.; Siegmund, A.; del Río, C.; Osses, P.; García, J. L.

    2016-06-01

    In the coastal Atacama Desert in Northern Chile plant growth is constrained to so-called `fog oases' dominated by monospecific stands of the genus Tillandsia. Adapted to the hyperarid environmental conditions, these plants specialize on the foliar uptake of fog as main water and nutrient source. It is this characteristic that leads to distinctive macro- and micro-scale distribution patterns, reflecting complex geo-ecological gradients, mainly affected by the spatiotemporal occurrence of coastal fog respectively the South Pacific Stratocumulus clouds reaching inlands. The current work employs remote sensing, machine learning and spatial pattern/GIS analysis techniques to acquire detailed information on the presence and state of Tillandsia spp. in the Tarapacá region as a base to better understand the bioclimatic and topographic constraints determining the distribution patterns of Tillandsia spp. Spatial and spectral predictors extracted from WorldView-3 satellite data are used to map present Tillandsia vegetation in the Tarapaca region. Regression models on Vegetation Cover Fraction (VCF) are generated combining satellite-based as well as topographic variables and using aggregated high spatial resolution information on vegetation cover derived from UAV flight campaigns as a reference. The results are a first step towards mapping and modelling the topographic as well as bioclimatic factors explaining the spatial distribution patterns of Tillandsia fog oases in the Atacama, Chile.

  4. Collaborative Approaches to Increase the Utility of Spatial Data for the Wildfire Management Community Through NASA's Applied Remote Sensing Training Program

    NASA Astrophysics Data System (ADS)

    McCullum, A. J. K.; Schmidt, C.; Blevins, B.; Weber, K.; Schnase, J. L.; Carroll, M.; Prados, A. I.

    2015-12-01

    The utility of spatial data products and tools to assess risk and effectively manage wildfires has increased, highlighting the need for communicating information about these new capabilities to decision makers, resource managers, and community leaders. NASA's Applied Remote Sensing Training (ARSET) program works directly with agencies and policy makers to develop in-person and online training courses that teach end users how to access, visualize, and apply NASA Earth Science data in their profession. The expansion of ARSET into wildfire applications began in 2015 with a webinar and subsequent in-person training hosted in collaboration with Idaho State University's (ISU) GIS Training and Research Center (TReC). These trainings featured presentations from the USDA Forest Service's Remote Sensing Training and Applications Center, the Land Processes DAAC, Northwest Nazarene University, NASA Goddard Space Flight Center, and ISU's GIS TReC. The webinar focused on providing land managers, non-governmental organizations, and international management agencies with an overview of 1) remote sensing platforms for wildfire applications, 2) products for pre- and post-fire planning and assessment, 3) the use of terrain data, 4) new techniques and technologies such as Unmanned Aircraft Systems and the Soil Moisture Active Passive Mission (SMAP), and 5) the RECOVER Decision Support System. This training highlighted online tools that engage the wildfire community through collaborative monitoring and assessment efforts. Webinar attendance included 278 participants from 178 organizations in 42 countries and 33 US states. The majority of respondents (93%) from a post-webinar survey indicated they displayed improvement in their understanding of specific remote-sensing data products appropriate for their work needs. With collaborative efforts between federal, state, and local agencies and academic institutions, increased use of NASA Earth Observations may lead to improved near real

  5. Chronic restricted access to 10% sucrose solution in adolescent and young adult rats impairs spatial memory and alters sensitivity to outcome devaluation.

    PubMed

    Kendig, Michael D; Boakes, Robert A; Rooney, Kieron B; Corbit, Laura H

    2013-08-15

    Although increasing consumption of sugar drinks is recognized as a significant public health concern, little is known about (a) the cognitive effects resulting from sucrose consumption; and (b) whether the long-term effects of sucrose consumption are more pronounced for adolescents. This experiment directly compared performance on a task of spatial learning and memory (the Morris Water Maze) and sensitivity to outcome devaluation following 28 days of 2-h/day access to a 10% sucrose solution in adolescent and young-adult Wistar rats. Sucrose groups developed elevated fasting blood glucose levels after the diet intervention, despite drawing <15% of calories from sucrose and gaining no more weight than controls. In subsequent behavioral testing, sucrose groups were impaired on the Morris Water Maze, with some residual deficits in spatial memory observed more than 6 weeks after the end of sucrose exposure. Further, results from outcome devaluation testing indicated that in the older cohort of rats, those fed sucrose showed reduced sensitivity to devaluation of the outcome, suggestive of differences in instrumental learning following sucrose exposure. Data provide strong evidence that sucrose consumption can induce deficits in spatial cognition and reward-oriented behavior at levels that resemble patterns of sugar drink consumption in young people, and which can remain long after exposure. PMID:23954407

  6. Assessing the spatial representativeness of eddy-covariance measurements of AmeriFlux network based on remote sensing and footprint analysis

    NASA Astrophysics Data System (ADS)

    Fu, D.; Zhang, L.; Chen, B.

    2015-12-01

    The eddy-covariance towers of AmeriFlux network are important for the analysis of terrestrial ecosystem-atmosphere interactions, and they have been used to improve our understanding of the mechanism behind terrestrial carbon cycle and upscaling from site to landscape and regional scales. However, the spatial representativeness of AmeriFlux network has not been assessed, especially accounting for the effects of land cover change on it using high spatial resolution data. Here we demonstrated an approach for evaluating the spatial representativeness of flux tower measurements based on footprint climatology analyses, land cover change data and remotely sensed vegetation indices. This method was applied to 79 flux towers of AmeriFlux network located in the continental United States, covering evergreen forest, deciduous forest, mixed forest, grass, cropland, shrub, and wetland biomes. For each site, monthly and annual footprint climatologies (i.e. monthly or annual accumulative footprints) were calculated using the Simple Analytical Footprint model on Eulerian coordinates (SAFE-f). The footprint climatologies were then overlaid on the images of Normalized Difference Vegetation Index (NDVI) and National Land Cover Database (NLCD) for the years (2001, 2006 and 2011), which were used as surrogates of land surface fluxes to assess the spatial representativeness. For most sites of AmeriFlux network, the results show that (i) the percentages of the target vegetation functional type (dominant land cover) observed by the AmeriFlux towers were higher than 60%; (ii) to some extent, most of the AmeriFlux sites presented anisotropically distributed patterns of NDVI within the 90% annual footprint climatology area; (iii) the land surface heterogeneity within the flux footprint area differed among sites; and (iv) the land cover types had changed higher than 10% within 6 km*6 km area centered at the flux tower for 5 AmeriFlux sites. We conclude that the footprint modeling based on high

  7. Estimating spatial variation in Alberta forest biomass from a combination of forest inventory and remote sensing data

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Huang, S.; Hogg, E. H.; Lieffers, V.; Qin, Y.; He, F.

    2013-12-01

    Uncertainties in the estimation of tree biomass carbon storage across large areas pose challenges for the study of forest carbon cycling at regional and global scales. In this study, we attempted to estimate the present biomass carbon storage in Alberta, Canada, by taking advantage of a spatially explicit dataset derived from a combination of forest inventory data from 1968 plots and spaceborne light detection and ranging (LiDAR) canopy height data. Ten climatic variables together with elevation, were used for model development and assessment. Four approaches, including spatial interpolation, non-spatial and spatial regression models, and decision-tree based modelling with random forests algorithm (a machine-learning technique), were compared to find the "best" estimates. We found that the random forests approach provided the best accuracy for biomass estimates. Non-spatial and spatial regression models gave estimates similar to random forests, while spatial interpolation greatly overestimated the biomass storage. Using random forests, the total biomass stock in Alberta forests was estimated to be 3.11 × 109 Mg, with the average biomass density of 77.59 Mg ha-1. At the species level, three major tree species, lodgepole pine, trembling aspen and white spruce, stocked about 1.91 × 109 Mg biomass, accounting for 61% of total estimated biomass. Spatial distribution of biomass varied with natural regions, land cover types, and species. And the relative importance of predictor variables on determining biomass distribution varied with species. This study showed that the combination of ground-based inventory data, spaceborne LiDAR data, land cover classification, climatic and environmental variables was an efficient way to estimate the quantity, distribution and variation of forest biomass carbon stocks across large regions.

  8. Estimating spatial variation in Alberta forest biomass from a combination of forest inventory and remote sensing data

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Huang, S.; Hogg, E. H.; Lieffers, V.; Qin, Y.; He, F.

    2014-05-01

    Uncertainties in the estimation of tree biomass carbon storage across large areas pose challenges for the study of forest carbon cycling at regional and global scales. In this study, we attempted to estimate the present aboveground biomass (AGB) in Alberta, Canada, by taking advantage of a spatially explicit data set derived from a combination of forest inventory data from 1968 plots and spaceborne light detection and ranging (lidar) canopy height data. Ten climatic variables, together with elevation, were used for model development and assessment. Four approaches, including spatial interpolation, non-spatial and spatial regression models, and decision-tree-based modeling with random forests algorithm (a machine-learning technique), were compared to find the "best" estimates. We found that the random forests approach provided the best accuracy for biomass estimates. Non-spatial and spatial regression models gave estimates similar to random forests, while spatial interpolation greatly overestimated the biomass storage. Using random forests, the total AGB stock in Alberta forests was estimated to be 2.26 × 109 Mg (megagram), with an average AGB density of 56.30 ± 35.94 Mg ha-1. At the species level, three major tree species, lodgepole pine, trembling aspen and white spruce, stocked about 1.39 × 109 Mg biomass, accounting for nearly 62% of total estimated AGB. Spatial distribution of biomass varied with natural regions, land cover types, and species. Furthermore, the relative importance of predictor variables on determining biomass distribution varied with species. This study showed that the combination of ground-based inventory data, spaceborne lidar data, land cover classification, and climatic and environmental variables was an efficient way to estimate the quantity, distribution and variation of forest biomass carbon stocks across large regions.

  9. Spatial discrimination deficits as a function of mnemonic interference in aged adults with and without memory impairment.

    PubMed

    Reagh, Zachariah M; Roberts, Jared M; Ly, Maria; DiProspero, Natalie; Murray, Elizabeth; Yassa, Michael A

    2014-03-01

    It is well established that aging is associated with declines in episodic memory. In recent years, an emphasis has emerged on the development of behavioral tasks and the identification of biomarkers that are predictive of cognitive decline in healthy as well as pathological aging. Here, we describe a memory task designed to assess the accuracy of discrimination ability for the locations of objects. Object locations were initially encoded incidentally, and appeared in a single space against a 5 × 7 grid. During retrieval, subjects viewed repeated object-location pairings, displacements of 1, 2, 3, or 4 grid spaces, and maximal corner-to-opposite-corner displacements. Subjects were tasked with judging objects in this second viewing as having retained their original location, or having moved. Performance on a task such as this is thought to rely on the capacity of the individual to perform hippocampus-mediated pattern separation. We report a performance deficit associated with a physically healthy aged group compared to young adults specific to trials with low mnemonic interference. Additionally, for aged adults, performance on the task was correlated with performance on the delayed recall portion of the Rey Auditory Verbal Learning Test (RAVLT), a neuropsychological test sensitive to hippocampal dysfunction. In line with prior work, dividing the aged group into unimpaired and impaired subgroups based on RAVLT Delayed Recall scores yielded clearly distinguishable patterns of performance, with the former subgroup performing comparably to young adults, and the latter subgroup showing generally impaired memory performance even with minimal interference. This study builds on existing tasks used in the field, and contributes a novel paradigm for differentiation of healthy from possible pathological aging, and may thus provide an avenue for early detection of age-related cognitive decline. PMID:24167060

  10. Treadmill exercise ameliorates impairment of spatial learning ability through enhancing dopamine expression in hypoxic ischemia brain injury in neonatal rats.

    PubMed

    Park, Chang-Youl; Lee, Shin-Ho; Kim, Bo-Kyun; Shin, Mal-Soon; Kim, Chang-Ju; Kim, Hong

    2013-01-01

    Substantia nigra and striatum are vulnerable to hypoxic ischemia brain injury. Physical exercise promotes cell survival and functional recovery after brain injury. However, the effects of treadmill exercise on nigro-striatal dopaminergic neuronal loss induced by hypoxic ischemia brain injury in neonatal stage are largely unknown. We determined the effects of treadmill exercise on survival of dopamine neurons in the substantia nigra and dopaminergic fibers in the striatum after hypoxic ischemia brain injury. On postnatal 7 day, left common carotid artery of the neonatal rats ligated for two hours and the neonatal rats were exposed to hypoxia conditions for one hour. The rat pups in the exercise groups were forced to run on a motorized treadmill for 30 min once a day for 12 weeks, starting 22 days after induction of hypoxic ischemia brain injury. Spatial learning ability in rat pups was determined by Morris water maze test after last treadmill exercise. The viability of dopamine neurons in the substantia nigra and dopamine fibers in the striatum were analyzed using immunohistochemistry. In this study, hypoxic ischemia injury caused loss of dopamine neurons in the substantia nigra and dopaminergic fibers in the striatum. Induction of hypoxic ischemia deteriorated spatial learning ability. Treadmill exercise ameliorated nigro-striatal dopaminergic neuronal loss, resulting in the improvement of spatial learning ability. The present study suggests the possibility that treadmill exercise in early adolescent period may provide a useful strategy for the recovery after neonatal hypoxic ischemia brain injury. PMID:24278893

  11. Prediction of historical forest habitat patterns using binomial distributions and simple Boolean logic from high spatial resolution remote sensing

    NASA Astrophysics Data System (ADS)

    Coops, Nicholas C.; Catling, Peter C.

    2001-08-01

    The identification of forest habitat, its spatial pattern and use by selected taxa is a vital step for the protection of biodiversity. The use of airborne videography and frequency distribution models based on historical habitat complexity data can provide detailed information on the spatial and temporal variation of habitat, respectively. The two techniques, however, have not been jointly applied to link the temporal variation in habitat to the spatial variation of habitat over the landscape to provide a complete historical picture of the variation of habitat quality of a forest estate. In this paper, a processing methodology is developed which allows the current spatial distribution of habitat quality to be used as a base to make retrospective predictions of the spatial extent and pattern of habitat quality over the landscape. This is achieved by projecting the spatial distribution of habitat complexity scores derived from the videography, backward in time using a combination of simple Boolean logic, estimated binomial distributions, and the use of random fluctuations to mimic natural forest dynamics that are likely to have occurred over the modeling period. The simulations provide information on the type and condition of habitat in recent history and can be linked to models predicting the abundance of a variety of common and endangered taxa.

  12. Partitioning the Controls on Carbon Flux Between Light Absorption and Light Use Efficiency: Insights From High Spatial and Temporal Resolution Remote Sensing.

    NASA Astrophysics Data System (ADS)

    Sims, D. A.; Kwon, H.; Luo, H.; Oechel, W.; Gamon, J.

    2001-12-01

    Comparisons between eddy covariance measurements of CO2 flux and remotely sensed spectral reflectance are often limited by mis-matches in temporal and spatial scales. Eddy flux measurements are made continuously through time whereas satellite sensors typically measure only once per day or less and many days may be lost because of cloud cover. In addition, satellite sensors such as MODIS have pixel sizes as large as a whole eddy flux footprint, making precise spatial correlation difficult. In order to better match the temporal and spatial scales of remote sensing measurements to those of eddy flux, we installed automated systems (optical sampling instruments on a tram system) within eddy covariance tower footprints at Sky Oaks field station near San Diego, CA. This system measured hyperspectral (narrow-band) reflectance over a 100 m transect throughout diurnal and seasonal cycles. These data were used to explore the controls on carbon flux and to develop models for scaling eddy flux measurements to the surrounding region. Fractional absorbed radiation (estimated from NDVI) varied dramatically over the diurnal cycle but was relatively constant across seasons in this evergreen shrub dominated system. By contrast, seasonal carbon flux varied more closely with optical signals of light-use efficiency. Consequently, large seasonal changes in carbon flux were primarily a function of light-use efficiency rather than light absorption. These data suggest that models based solely on light absorption by vegetation may miss large fluctuations in carbon exchange resulting from downregulation of photosynthesis. Although this ecosystem may be an extreme case, there are many evergreen ecosystems in which photosynthetic downregulation could play a large role. Application of this optical measuring system at other FLUXNET sites would greatly increase our understanding of the role of photosynthetic downregulation in global carbon cycles.

  13. Assessing regional environmental quality by integrated use of remote sensing, GIS, and spatial multi-criteria evaluation for prioritization of environmental restoration.

    PubMed

    Rahman, Md Rejaur; Shi, Z H; Chongfa, Cai

    2014-11-01

    This study was an attempt to analyse the regional environmental quality with the application of remote sensing, geographical information system, and spatial multiple criteria decision analysis and, to project a quantitative method applicable to identify the status of the regional environment of the study area. Using spatial multi-criteria evaluation (SMCE) approach with expert knowledge in this study, an integrated regional environmental quality index (REQI) was computed and classified into five levels of regional environment quality viz. worse, poor, moderate, good, and very good. During the process, a set of spatial criteria were selected (here, 15 criterions) together with the degree of importance of criteria in sustainability of the regional environment. Integrated remote sensing and GIS technique and models were applied to generate the necessary factors (criterions) maps for the SMCE approach. The ranking, along with expected value method, was used to standardize the factors and on the other hand, an analytical hierarchy process (AHP) was applied for calculating factor weights. The entire process was executed in the integrated land and water information system (ILWIS) software tool that supports SMCE. The analysis showed that the overall regional environmental quality of the area was at moderate level and was partly determined by elevation. Areas under worse and poor quality of environment indicated that the regional environmental status showed decline in these parts of the county. The study also revealed that the human activities, vegetation condition, soil erosion, topography, climate, and soil conditions have serious influence on the regional environment condition of the area. Considering the regional characteristics of environmental quality, priority, and practical needs for environmental restoration, the study area was further regionalized into four priority areas which may serve as base areas of decision making for the recovery, rebuilding, and

  14. Design and technical evaluation of an enhanced location-awareness service enabler for spatial disorientation management of elderly with mild cognitive impairment.

    PubMed

    Moreno, Pedro A; Hernando, M Elena; Gómez, Enrique J

    2015-01-01

    The progressive ageing of population has turned the mild cognitive impairment (MCI) into a prevalent disease suffered by elderly. Consequently, the spatial disorientation has become a significant problem for older people and their caregivers. The ambient-assisted living applications are offering location-based services for empowering elderly to go outside and encouraging a greater independence. Therefore, this paper describes the design and technical evaluation of a location-awareness service enabler aimed at supporting and managing probable wandering situations of a person with MCI. Through the presence capabilities of the IP multimedia subsystem (IMS) architecture, the service will alert patient's contacts if a hazardous situation is detected depending on his location. Furthermore, information about the older person's security areas has been included in the user profile managed by IMS. In doing so, the service enabler introduced contribute to "context-awareness" paradigm allowing the adaptation and personalization of services depending on user's context and specific conditions or preferences. PMID:25486651

  15. Developmental 3,4-methylenedioxymethamphetamine (MDMA) impairs sequential and spatial but not cued learning independent of growth, litter effects or injection stress.

    PubMed

    Williams, Michael T; Morford, LaRonda L; Wood, Sandra L; Rock, Stephanie L; McCrea, Anne E; Fukumura, Masao; Wallace, Tanya L; Broening, Harry W; Moran, Mary S; Vorhees, Charles V

    2003-04-01

    Previously, we have shown that rats administered MDMA from postnatal (P) days 11-20 had reductions in body weight during the period of treatment and as adults they had deficits in sequential and spatial learning and memory. In the present study, to control for weight reductions, we used litters with double the number of offspring to induce growth restriction comparable to that of standard size litters treated with MDMA. Litters were treated twice daily from P11 to 20 with vehicle or MDMA (20 mg/kg) or only weighed. Males, but not females, exposed to MDMA had longer latencies and more errors in the Cincinnati water maze compared to males of the other treatments. In the Morris water maze (210 cm pool, 10x10 cm platform), the MDMA animals were impaired relative to all other treatments during acquisition. Only the MDMA females showed deficits when the platform was shifted to a new location, however, both MDMA males and females were impaired when the location of the platform was again shifted and a reduced platform (5x5 cm) used. No differences were observed in the ability to swim a straight channel, locate a platform with a cue, or the endocrine response to forced swim among the treatment groups. No differences were seen between animals injected with saline and those only weighed. The data suggest that factors, such as growth retardation, multiple injections, or the composition of the litter, do not affect the development of learning and memory impairments resulting from P11 to 20 MDMA exposure. The large litter approach offers a novel method to control for undernutrition during the preweaning period in rodents. PMID:12644267

  16. Effect of Beta-Asarone on Impairment of Spatial Working Memory and Apoptosis in the Hippocampus of Rats Exposed to Chronic Corticosterone Administration

    PubMed Central

    Lee, Bombi; Sur, Bongjun; Cho, Seong-Guk; Yeom, Mijung; Shim, Insop; Lee, Hyejung; Hahm, Dae-Hyun

    2015-01-01

    β-asarone (BAS) is an active component of Acori graminei rhizoma, a traditional medicine used clinically in treating dementia and chronic stress in Korea. However, the cognitive effects of BAS and its mechanism of action have remained elusive. The purpose of this study was to examine whether BAS improved spatial cognitive impairment induced in rats following chronic corticosterone (CORT) administration. CORT administration (40 mg/kg, i.p., 21 days) resulted in cognitive impairment in the avoidance conditioning test (AAT) and the Morris water maze (MWM) test that was reversed by BAS (200 mg/kg, i.p). Additionally, as assessed by immunohistochemistry and RT-PCR analysis, the administration of BAS significantly alleviated memory-associated decreases in the expression levels of brain-derived neurotrophic factor (BDNF) and cAMP-response element-binding protein (CREB) proteins and mRNAs in the hippocampus. Also, BAS administration significantly restored the expression of Bax and Bcl-2 mRNAs in the hippocampus. Thus, BAS may be an effective therapeutic for learning and memory disturbances, and its neuroprotective effect was mediated, in part, by normalizing the CORT response, resulting in regulation of BDNF and CREB functions and anti-apoptosis in rats. PMID:26535083

  17. Effect of Beta-Asarone on Impairment of Spatial Working Memory and Apoptosis in the Hippocampus of Rats Exposed to Chronic Corticosterone Administration.

    PubMed

    Lee, Bombi; Sur, Bongjun; Cho, Seong-Guk; Yeom, Mijung; Shim, Insop; Lee, Hyejung; Hahm, Dae-Hyun

    2015-11-01

    β-asarone (BAS) is an active component of Acori graminei rhizoma, a traditional medicine used clinically in treating dementia and chronic stress in Korea. However, the cognitive effects of BAS and its mechanism of action have remained elusive. The purpose of this study was to examine whether BAS improved spatial cognitive impairment induced in rats following chronic corticosterone (CORT) administration. CORT administration (40 mg/kg, i.p., 21 days) resulted in cognitive impairment in the avoidance conditioning test (AAT) and the Morris water maze (MWM) test that was reversed by BAS (200 mg/kg, i.p). Additionally, as assessed by immunohistochemistry and RT-PCR analysis, the administration of BAS significantly alleviated memory-associated decreases in the expression levels of brain-derived neurotrophic factor (BDNF) and cAMP-response element-binding protein (CREB) proteins and mRNAs in the hippocampus. Also, BAS administration significantly restored the expression of Bax and Bcl-2 mRNAs in the hippocampus. Thus, BAS may be an effective therapeutic for learning and memory disturbances, and its neuroprotective effect was mediated, in part, by normalizing the CORT response, resulting in regulation of BDNF and CREB functions and anti-apoptosis in rats. PMID:26535083

  18. The effects of tamoxifen on spatial and nonspatial learning and memory impairments induced by scopolamine and the brain tissues oxidative damage in ovariectomized rats

    PubMed Central

    Karimi, Sareh; Hejazian, Seyed Hassan; Alikhani, Vajiheh; Hosseini, Mahmoud

    2015-01-01

    Background: Modulatory effects of tamoxifen (TAM) on the central nervous system have been reported. The effects of TAM on spatial and nonspatial learning and memory impairments induced by scopolamine and the brain tissues oxidative damage was investigated. Materials and Methods: The ovariectomized (OVX) rats were divided and treated: (1) Control (saline), (2) scopolamine (Sco; 2 mg/kg, 30 min before behavioral tests), (3–5) Sco-TAM 1, Sco-TAM 3 and Sco-TAM 10. TAM (1, 3 or 10 mg/kg; i.p.) was daily administered for 6 weeks. Results: In Morris water maze (MWM), both the latency and traveled distance in the Sco-group were higher than control (P < 0.001) while, in the Sco-TAM 10 group it was lower than Sco-group (P < 0.05). In passive avoidance test, the latency to enter the dark compartment was higher than control (P < 0.05 – P < 0.01). Pretreatment by all three doses of TAM prolonged the latency to enter the dark compartment compared to Sco-group (P < 0.05 – P < 0.001). The brain tissues malondialdehyde (MDA) concentration was increased while, superoxide dismutase activity (SOD) decreased in the Sco-group compared to control (P < 0.05 – P < 0.01). Pretreatment by TAM lowered the concentration of MDA while, increased SOD compared to Sco-group (P < 0.05 – P < 0.001). Conclusions: It is suggested that TAM prevents spatial and nonspatial learning and memory impairments induced by scopolamine in OVX rats. The possible mechanism(s) might at least in part be due to protection against the brain tissues oxidative damage. PMID:26601084

  19. Hearing impairment induces frequency-specific adjustments in auditory spatial tuning in the optic tectum of young owls.

    PubMed

    Gold, J I; Knudsen, E I

    1999-11-01

    Bimodal, auditory-visual neurons in the optic tectum of the barn owl are sharply tuned for sound source location. The auditory receptive fields (RFs) of these neurons are restricted in space primarily as a consequence of their tuning for interaural time differences and interaural level differences across broad ranges of frequencies. In this study, we examined the extent to which frequency-specific features of early auditory experience shape the auditory spatial tuning of these neurons. We manipulated auditory experience by implanting in one ear canal an acoustic filtering device that altered the timing and level of sound reaching the eardrum in a frequency-dependent fashion. We assessed the auditory spatial tuning at individual tectal sites in normal owls and in owls raised with the filtering device. At each site, we measured a family of auditory RFs using broadband sound and narrowband sounds with different center frequencies both with and without the device in place. In normal owls, the narrowband RFs for a given site all included a common region of space that corresponded with the broadband RF and aligned with the site's visual RF. Acute insertion of the filtering device in normal owls shifted the locations of the narrowband RFs away from the visual RF, the magnitude and direction of the shifts depending on the frequency of the stimulus. In contrast, in owls that were raised wearing the device, narrowband and broadband RFs were aligned with visual RFs so long as the device was in the ear but not after it was removed, indicating that auditory spatial tuning had been adaptively altered by experience with the device. The frequency tuning of tectal neurons in device-reared owls was also altered from normal. The results demonstrate that experience during development adaptively modifies the representation of auditory space in the barn owl's optic tectum in a frequency-dependent manner. PMID:10561399

  20. Rats with hippocampal lesion show impaired learning and memory in the ziggurat task: a new task to evaluate spatial behavior.

    PubMed

    Faraji, Jamshid; Lehmann, Hugo; Metz, Gerlinde A; Sutherland, Robert J

    2008-05-16

    Spatial tasks are widely used to determine the function of limbic system structures in rats. The present study used a new task designed to evaluate spatial behavior, the ziggurat task (ZT), to examine the performance of rats with widespread hippocampal damage induced by N-methyl-d-aspartic acid (NMDA). The task consisted of an open field containing 16 identical ziggurats (pyramid shaped towers) arranged at equal distances. One of the ziggurats was baited with a food reward. The task required rats to navigate through the open field by using a combination of distal and/or proximal cues in order to locate the food reward. The ability to acquire and recall the location of the goal (baited) ziggurat was tested in consecutive training sessions of eight trials per day for 10 days. The location of the goal ziggurat was changed every second day, requiring the rats to learn a total of five different locations. Several parameters, including latency to find the target, distance traveled, the number of visits to non-baited ziggurats (errors), and the number of returns were used as indices of learning and memory. Control rats showed a significant decrease in distance traveled and reduced latency in locating the goal ziggurat across trials and days, suggesting that they learned and remembered the location of the goal ziggurat. Interestingly, the hippocampal-damaged group moved significantly faster, and traveled longer distances compared to the control group. Significant differences were observed between these groups with respect to the number of errors and returns on test days. Day 11 served as probe day, in which no food reward was given. The controls spent more time searching for the food in the previous training quadrant compared to the hippocampal group. The findings demonstrate that the ZT is a sensitive and efficient dry task for measuring hippocampus-dependent spatial performance in rats requiring little training and not associated with some of the disadvantages of water

  1. Achievements of the DOT-NASA Joint Program on Remote Sensing and Spatial Information Technologies: Application to Multimodal Transportation

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This report presents three-year accomplishments from the national program on Commercial Remote Sensing and Geospatial Technology (CRSGT) application to transportation, administered by the U.S. Department of Transportation (U.S. DOT) in collaboration with the National Aeronautics and Space Administration (NASA). The joint program was authorized under Section 5113 of the Transportation Equity Act for the 21st Century (TEA-21). This is the first national program of its type focusing on transportation applications of emerging commercial remote sensing technologies. U.S. DOT's Research and Special Programs Administration manages the program in coordination with NASA's Earth Science Enterprise's application programs. The program focuses on applications of CRSGT products and systems for providing smarter and more efficient transportation operations and services. The program is performed in partnership with four major National Consortia for Remote Sensing in Transportation (NCRST). Each consortium focuses on research and development of products in one of the four priority areas for transportation application, and includes technical application and demonstration projects carried out in partnership with industries and service providers in their respective areas. The report identifies products and accomplishments from each of the four consortia in meeting the goal of providing smarter and more efficient transportation services. The products and results emerging from the program are being implemented in transportation operations and services through state and local agencies. The Environmental Assessment and Application Consortium (NCRST-E) provides leadership for developing and deploying cost effective environmental and transportation planning services, and integrates CRSGT advances for achieving smarter and cost effective corridor planning. The Infrastructure Management Consortium (NCRST-I) provides leadership in technologies that achieve smarter and cheaper ways of managing

  2. Aircraft remote sensing of phytoplankton spatial patterns during the 1989 Joint Global Ocean Flux Study (JGOFS) North Atlantic bloom experiment

    NASA Technical Reports Server (NTRS)

    Yoder, James A.; Hoge, Frank E.

    1991-01-01

    Mesoscale phytoplankton chlorophyll variability near the Joint Global Ocean Flux study sites along the 20 W meridian at 34 N, 47 N, and 59 N is discussed. The NASA P-3 aircraft and the Airborne Oceanographic Lidar (AOL) system provides remote sensing support for the North Atlantic Bloom Experiment. The principal instrument of the AOL system is the blue-green laser that stimulates fluorescence from photoplankton chlorophyll, the principal photosynthetic pigment. Other instruments on the NASA P-3 aircraft include up- and down-looking spectrometers, PRT-5 for infrared measurements to determine sea surface temperature, and a system to deploy and record AXBTs to measure subsurface temperature structure.

  3. Forming first impressions of others in schizophrenia: impairments in fast processing and in use of spatial frequency information.

    PubMed

    Vakhrusheva, J; Zemon, V; Bar, M; Weiskopf, N G; Tremeau, F; Petkova, E; Su, Z; Abeles, I Y; Butler, P D

    2014-12-01

    Individuals form first impressions of others all the time, which affects their social functioning. Typical adults form threat impressions in faces with neutral expressions quickly, requiring less than 40 ms. These impressions appear to be mediated by low spatial frequency (LSF) content in the images. Little is known, however, about mechanisms of first impression formation in schizophrenia. The current study investigated how quickly individuals with schizophrenia can form consistent impressions of threat compared with controls and explored the mechanisms involved. Patients and controls were presented intact, LSF- or high spatial frequency (HSF)-filtered faces with durations that varied from 39 to 1703 ms and were asked to rate how threatening each face was on a scale from 1 to 5. In order to assess the speed of impression formation for intact faces, correlations were calculated for ratings made at each duration compared to a reference duration of 1703 ms for each group. Controls demonstrated a significant relation for intact faces presented for 39 ms, whereas patients required 390 ms to demonstrate a significant relation with the reference duration. For controls, LSFs primarily contributed to the formation of consistent threat impressions at 39 ms, whereas patients showed a trend for utilizing both LSF and HSF information to form consistent threat impressions at 390 ms. Results indicate that individuals with schizophrenia require a greater integration time to form a stable "first impression" of threat, which may be related to the need to utilize compensatory mechanisms such as HSF, as well as LSF, information. PMID:25458862

  4. Disrupted Functional Connectivity for Controlled Visual Processing as a Basis for Impaired Spatial Working Memory in Schizophrenia

    PubMed Central

    Kang, Seung Suk; Sponheim, Scott R.; Chafee, Matthew V.; MacDonald, Angus W.

    2011-01-01

    Although regional brain abnormalities underlying spatial working memory (SWM) deficits in schizophrenia have been identified, little is known about which brain circuits are functionally disrupted in the SWM network in schizophrenia. We investigated SWM-related interregional functional connectivity in schizophrenia using functional magnetic resonance imaging (fMRI) data collected during a memory task that required analysis of spatial information in object structure. Twelve schizophrenia patients and eleven normal control subjects participated. Patients had SWM performance deficits and deficient neural activation in various brain areas, especially in the high SWM load condition. Examination of the covariation of regional brain activations elicited by the SWM task revealed evidence of functional disconnection between prefrontal and posterior visual association areas in schizophrenia. Under low SMW load, we found reduced functional associations between dorsolateral prefrontal cortex (DLPFC) and inferior temporal cortex (ITC) in the right hemisphere in patients. Under high SWM load, we found evidence for further functional disconnection in patients, including additional reduced functional associations between left DLPFC and right visual areas, including the posterior parietal cortex (PPC), fusiform gyrus, and V1, as well as between right inferior frontal cortex and right PPC. Greater prefrontal-posterior cortical functional connectivity was associated with better SWM performance in controls, but not in patients. These results suggest that prefrontal-posterior functional connectivity associated with the maintenance and control of visual information is central to SWM, and that disruption of this functional network underlies SWM deficits in schizophrenia. PMID:21703287

  5. Hazards analysis and prediction from remote sensing and GIS using spatial data mining and knowledge discovery: a case study for landslide hazard zonation

    NASA Astrophysics Data System (ADS)

    Hsu, Pai-Hui; Su, Wen-Ray; Chang, Chy-Chang

    2011-11-01

    Due to the particular geographical location and geological condition, Taiwan suffers from many natural hazards which often cause series property damages and life losses. To reduce the damages and casualty, an effective real-time system for hazard prediction and mitigation is necessary. In this study, a case study for Landslide Hazard Zonation (LHZ) is tested in accordance with Spatial Data Mining and Knowledge Discovery (SDMKD) from database. Many different kinds of geospatial data, such as the terrain elevation, land cover types, the distance to roads and rivers, geology maps, NDVI, and monitoring rainfall data etc., are collected into the database for SDMKD. In order to guarantee the data quality, the spatial data cleaning is essential to remove the noises, errors, outliers, and inconsistency hiding in the input spatial data sets. In this paper, the Kriging interpolation is used to calibrate the QPESUMS rainfall data to the rainfall observations from rain gauge stations to remove the data inconsistency. After the data cleaning, the artificial neural networks (ANNs) is applied to generate the LHZ map throughout the test area. The experiment results show that the accuracy of LHZ is about 92.3% with the ANNs analysis, and the landslides induced by heavy-rainfall can be mapped efficiently from remotely sensed images and geospatial data using SDMKD technologies.

  6. An Improved STARFM with Help of an Unmixing-Based Method to Generate High Spatial and Temporal Resolution Remote Sensing Data in Complex Heterogeneous Regions.

    PubMed

    Xie, Dengfeng; Zhang, Jinshui; Zhu, Xiufang; Pan, Yaozhong; Liu, Hongli; Yuan, Zhoumiqi; Yun, Ya

    2016-01-01

    Remote sensing technology plays an important role in monitoring rapid changes of the Earth's surface. However, sensors that can simultaneously provide satellite images with both high temporal and spatial resolution haven't been designed yet. This paper proposes an improved spatial and temporal adaptive reflectance fusion model (STARFM) with the help of an Unmixing-based method (USTARFM) to generate the high spatial and temporal data needed for the study of heterogeneous areas. The results showed that the USTARFM had higher accuracy than STARFM methods in two aspects of analysis: individual bands and of heterogeneity analysis. Taking the predicted NIR band as an example, the correlation coefficients (r) for the USTARFM, STARFM and unmixing methods were 0.96, 0.95, 0.90, respectively (p-value < 0.001); Root Mean Square Error (RMSE) values were 0.0245, 0.0300, 0.0401, respectively; and ERGAS values were 0.5416, 0.6507, 0.8737, respectively. The USTARM showed consistently higher performance than STARM when the degree of heterogeneity ranged from 2 to 10, highlighting that the use of this method provides the capacity to solve the data fusion problems faced when using STARFM. Additionally, the USTARFM method could help researchers achieve better performance than STARFM at a smaller window size from its heterogeneous land surface quantitative representation. PMID:26861334

  7. On the development of in-flight autonomous integrity monitoring of stored geo-spatial data using forward-looking remote sensing technology

    NASA Astrophysics Data System (ADS)

    Young, Steven D.

    Synthetic Vision Systems have been proposed that integrate traditional information provided by Primary Flight Displays with depictions of terrain and other geo-spatial features. As validation is impractical, the geo-spatial models used by an SVS typically have no inherent integrity. This has been a primary constraint to approved use as other than "advisory-only" in civil aviation. This dissertation describes a general approach to using forward-looking remote sensing technology as part of an in-flight monitor that provides a bounded level of integrity for geo-spatial feature data. After reviewing a taxonomy of sensor technologies and applications relevant to the premise, a specific proof-of-concept implementation using X-band radar is discussed. Terrain shadowing features, as seen by the radar, are compared in a statistical manner against estimated shadow features extracted from a stored terrain model as viewed from the perspective of the airborne observer. A test statistic is defined that enables detection of errors as small as the range resolution of the radar. Experimental results obtained from multiple aircraft platforms hosting certified commercial-off-the-shelf X-band radars test the premise.

  8. An Improved STARFM with Help of an Unmixing-Based Method to Generate High Spatial and Temporal Resolution Remote Sensing Data in Complex Heterogeneous Regions

    PubMed Central

    Xie, Dengfeng; Zhang, Jinshui; Zhu, Xiufang; Pan, Yaozhong; Liu, Hongli; Yuan, Zhoumiqi; Yun, Ya

    2016-01-01

    Remote sensing technology plays an important role in monitoring rapid changes of the Earth's surface. However, sensors that can simultaneously provide satellite images with both high temporal and spatial resolution haven’t been designed yet. This paper proposes an improved spatial and temporal adaptive reflectance fusion model (STARFM) with the help of an Unmixing-based method (USTARFM) to generate the high spatial and temporal data needed for the study of heterogeneous areas. The results showed that the USTARFM had higher accuracy than STARFM methods in two aspects of analysis: individual bands and of heterogeneity analysis. Taking the predicted NIR band as an example, the correlation coefficients (r) for the USTARFM, STARFM and unmixing methods were 0.96, 0.95, 0.90, respectively (p-value < 0.001); Root Mean Square Error (RMSE) values were 0.0245, 0.0300, 0.0401, respectively; and ERGAS values were 0.5416, 0.6507, 0.8737, respectively. The USTARM showed consistently higher performance than STARM when the degree of heterogeneity ranged from 2 to 10, highlighting that the use of this method provides the capacity to solve the data fusion problems faced when using STARFM. Additionally, the USTARFM method could help researchers achieve better performance than STARFM at a smaller window size from its heterogeneous land surface quantitative representation. PMID:26861334

  9. Spatial distribution of debris thickness and melting from remote-sensing and meteorological data, at debris-covered Baltoro glacier, Karakoram, Pakistan

    NASA Astrophysics Data System (ADS)

    Mihalcea, C.; Mayer, C.; Diolaiuti, G.; D'Agata, C.; Smiraglia, C.; Lambrecht, A.; Vuillermoz, E.; Tartari, G.

    A distributed surface energy-balance study was performed to determine sub-debris ablation across a large part of Baltoro glacier, a wide debris-covered glacier in the Karakoram range, Pakistan. The study area is ˜124 km2. The study aimed primarily at analyzing the influence of debris thickness on the melt distribution. The spatial distribution of the physical and thermal characteristics of the debris was calculated from remote-sensing (ASTER image) and field data. Meteorological data from an automatic weather station at Urdukas (4022 m a.s.l.), located adjacent to Baltoro glacier on a lateral moraine, were used to calculate the spatial distribution of energy available for melting during the period 1-15 July 2004. The model performance was evaluated by comparisons with field measurements for the same period. The model is reliable in predicting ablation over wide debris-covered areas. It underestimates melt rates over highly crevassed areas and water ponds with a high variability of the debris thickness distribution in the vicinity, and over areas with very low debris thickness (<0.03 m). We also examined the spatial distribution of the energy-balance components (global radiation and surface temperature) over the study area. The results allow us to quantify, for the study period, a meltwater production of 0.058 km3.

  10. Accuracy levels of land cover classified maps derived from mid and high spatial resolution remote sensing data

    NASA Astrophysics Data System (ADS)

    Brown, Bonnie J.

    This dissertation compares the accuracy of results of classifying data from mid-level to very high spatial resolutions (Landsat ETM+, SPOT 4, ASTER, SPOT 5, and QuickBird). Data from all of these sensors were classified for both urban and rural settings. The dissertation also examines accuracy levels between spectral and radiometric resolutions. Finally, it investigates the role that shadow plays in affecting accuracy levels from higher spatial resolution satellites. To compare as to whether there were significant differences in the accuracy levels between different sensors, each map's accuracy percentages were analyzed using Z-scores and kappa as described in the methodology section. QuickBird, with the highest spatial resolution, performed significantly more poorly in terms of providing accurate classification than any other sensor with respect to the rural environment. It also was significantly worse than Landsat ETM+ in providing accurate classification in the urban environment. In order to control for radiometric resolution, the 11-bit QuickBird data were converted to 8-bit data since QuickBird is the only sensor that does not have the same radiometric resolution. The resulting classification accuracy percentages were no better than that of random chance. When testing for accuracy in classification using only the three bands common to all sensors (green, red, and near-infrared) the result was there was essentially no difference between any of the sensors. This outcome supports the hypothesis that spectral resolution plays an important role in land cover accuracy. Using simple linear regression, the relationship between the percentage of shadow pixels and spatial resolution is examined. There is a moderate relationship between the spatial resolution of sensors and the percentages of shadow pixels where sensors with higher spatial resolution have a higher percentage of shadow pixels. These results agreed with literature from other studies in similar environments.

  11. Combining Remote Sensing imagery of both fine and coarse spatial resolution to Estimate Crop Evapotranspiration and quantifying its Influence on Crop Growth Monitoring.

    NASA Astrophysics Data System (ADS)

    Sepulcre-Cantó, Guadalupe; Gellens-Meulenberghs, Françoise; Arboleda, Alirio; Duveiller, Gregory; Piccard, Isabelle; de Wit, Allard; Tychon, Bernard; Bakary, Djaby; Defourny, Pierre

    2010-05-01

    This study has been carried out in the framework of the GLOBAM -Global Agricultural Monitoring system by integration of earth observation and modeling techniques- project whose objective is to fill the methodological gap between the state of the art of local crop monitoring and the operational requirements of the global monitoring system programs. To achieve this goal, the research aims to develop an integrated approach using remote sensing and crop growth modeling. Evapotranspiration (ET) is a valuable parameter in the crop monitoring context since it provides information on the plant water stress status, which strongly influences crop development and, by extension, crop yield. To assess crop evapotranspiration over the GLOBAM study areas (300x300 km sites in Northern Europe and Central Ethiopia), a Soil-Vegetation-Atmosphere Transfer (SVAT) model forced with remote sensing and numerical weather prediction data has been used. This model runs at pre-operational level in the framework of the EUMETSAT LSA-SAF (Land Surface Analysis Satellite Application Facility) using SEVIRI and ECMWF data, as well as the ECOCLIMAP database to characterize the vegetation. The model generates ET images at the Meteosat Second Generation (MSG) spatial resolution (3 km at subsatellite point),with a temporal resolution of 30 min and monitors the entire MSG disk which covers Europe, Africa and part of Sud America . The SVAT model was run for 2007 using two approaches. The first approach is at the standard pre-operational mode. The second incorporates remote sensing information at various spatial resolutions going from LANDSAT (30m) to SEVIRI (3-5 km) passing by AWIFS (56m) and MODIS (250m). Fine spatial resolution data consists of crop type classification which enable to identify areas where pure crop specific MODIS time series can be compiled and used to derive Leaf Area Index estimations for the most important crops (wheat and maize). The use of this information allowed to characterize

  12. REMOTE SENSING AND SPATIALLY EXPLICIT LANDSCAPE-BASED NITROGEN MODELING METHODS DEVELOPMENT IN THE NEUSE RIVER BASIN, NC

    EPA Science Inventory

    The objective of this research was to model and map the spatial patterns of excess nitrogen (N) sources across the landscape within the Neuse River Basin (NRB) of North
    Carolina. The process included an initial land cover characterization effort to map landscape "patches" at ...

  13. A retroactive spatial cue improved VSTM capacity in mild cognitive impairment and medial temporal lobe amnesia but not in healthy older adults.

    PubMed

    Newsome, Rachel N; Duarte, Audrey; Pun, Carson; Smith, Victoria M; Ferber, Susanne; Barense, Morgan D

    2015-10-01

    Visual short-term memory (VSTM) is a vital cognitive ability, connecting visual input with conscious awareness. VSTM performance declines with mild cognitive impairment (MCI) and medial temporal lobe (MTL) amnesia. Many studies have shown that providing a spatial retrospective cue ("retrocue") improves VSTM capacity estimates for healthy young adults. However, one study has demonstrated that older adults are unable to use a retrocue to inhibit irrelevant items from memory. It is unknown whether patients with MCI and MTL amnesia will be able to use a retrocue to benefit their memory. We administered a retrocue and a baseline (simultaneous cue, "simucue") task to young adults, older adults, MCI patients, and MTL cases. Consistent with previous findings, young adults showed a retrocue benefit, whereas healthy older adults did not. In contrast, both MCI patients and MTL cases showed a retrocue benefit--the use of a retrocue brought patient performance up to the level of age-matched controls. We speculate that the patients were able to use the spatial information from the retrocue to reduce interference and facilitate binding items to their locations. PMID:26300388

  14. Perinatal exposure to genistein, a soy phytoestrogen, improves spatial learning and memory but impairs passive avoidance learning and memory in offspring.

    PubMed

    Kohara, Yumi; Kuwahara, Rika; Kawaguchi, Shinichiro; Jojima, Takeshi; Yamashita, Kimihiro

    2014-05-10

    This study investigated the effects of perinatal genistein (GEN) exposure on the central nervous system of rat offspring. Pregnant dams orally received GEN (1 or 10 mg/kg/day) or vehicle (1 ml/kg/day) from gestation day 10 to postnatal day 14. In order to assess the effects of GEN on rat offspring, we used a battery of behavioral tests, including the open-field, elevated plus-maze, MAZE and step-through passive avoidance tests. MAZE test is an appetite-motivation test, and we used this mainly for assessing spatial learning and memory. In the MAZE test, GEN groups exhibited shorter latency from start to goal than the vehicle-treated group in both sexes. On the other hand, performances in the step-through passive avoidance test were non-monotonically inhibited by GEN in both sexes, and a significant difference was observed in low dose of the GEN-treated group compared to the vehicle-treated group in female rats. Furthermore, we found that perinatal exposure to GEN did not significantly alter locomotor activity or emotionality as assessed by the open-field and elevated-plus maze tests. These results suggest that perinatal exposure to GEN improved spatial learning and memory of rat offspring, but impaired their passive avoidance learning and memory. PMID:24637062

  15. Reconsolidation of a long-term spatial memory is impaired by cycloheximide when reactivated with a contextual latent learning trial in male and female rats.

    PubMed

    Flint, R W; Valentine, S; Papandrea, D

    2007-09-21

    Reconsolidation of long-term memory has become a topic of great interest in recent years, and has the potential to provide important information regarding memory processes and the treatment of memory-related disorders. The present study examined the role of systemic protein synthesis inhibition in reconsolidation of a long-term spatial memory reactivated by a contextual latent learning trial in male and female rats. Using the Morris water maze, we demonstrate that: 1) a contextual latent reactivation treatment enhances memory, 2) systemic protein synthesis inhibition selectively impairs test performance when administered in conjunction with a memory reactivation treatment, and 3) that these effects are more pronounced in female rats. These findings indicate a role for protein synthesis in the reconsolidation of a contextually reactivated long-term spatial memory using the water maze, and a potential differential effect of sex in this apparatus. The role of the strength of the memory trace is discussed and the relevance of these findings to theories of reconsolidation and therapeutic treatment of post-traumatic stress disorder is discussed. PMID:17766047

  16. Treadmill exercise alleviates prenatal noise stress-induced impairment of spatial learning ability through enhancing hippocampal neurogenesis in rat pups

    PubMed Central

    Kim, Tae-Woon; Shin, Mal-Soon; Park, Joon-Ki; Shin, Mi-Ai; Lee, Hee-Hyuk; Lee, Sam-Jun

    2013-01-01

    Stress alters brain cell properties and then disturbs cognitive processes, such as learning and memory. In this study, we investigated the effect of postnatal treadmill exercise on hippocampal neurogenesis and spatial learning ability of rat pups following prenatal noise stress. The impact of exercise intensity (mild-intensity exercise vs heavy-intensity exercise) was also compared. The pregnant rats in the stress-applied group were exposed to a 95 dB supersonic machine sound for 1 h once a day from the 15th day after mating until delivery. After birth, the rat pups in the exercise groups were made to run on a treadmill for 30 min once a day for 7 consecutive days, starting 4 weeks after birth. The spatial learning ability was tested using radial-arm maze task and hippocampal neurogenesis was determined by 5-bromo-2′-deoxyuridine (BrdU) immunohistochemistry. The rat pups born from the stress-applied maternal rats spent more time for the seeking of water and showed higher number of error in the radial-arm maze task compared to the control group. These rat pups showed suppressed neurogenesis in the hippocampus. In contrast, the rat pups performed postnatal treadmill exercise saved time for seeking of water and showed lower number of error compared to the stress-applied group. Postnatal treadmill exercise also enhanced neurogenesis in the hippocampus. The mild-intensity exercise showed more potent impact compared to the heavy-intensity exercise. The present results reveal that postnatal treadmill exercise lessens prenatal stress-induced deterioration of brain function in offspring. PMID:24282804

  17. Gait Biomechanics, Spatial and Temporal Characteristics, and the Energy Cost of Walking in Older Adults With Impaired Mobility

    PubMed Central

    Brach, Jennifer; Perera, Subashan; VanSwearingen, Jessie M.

    2010-01-01

    Background Abnormalities of gait and changes in posture during walking are more common in older adults than in young adults and may contribute to an increase in the energy expended for walking. Objective The objective of this study was to examine the contributions of abnormalities of gait biomechanics (hip extension, trunk flexion, and foot-floor angle at heel-strike) and gait characteristics (step width, stance time, and cadence) to the energy cost of walking in older adults with impaired mobility. Design A cross-sectional design was used. Methods Gait speed, step width, stance time, and cadence were derived during walking on an instrumented walkway. Trunk flexion, hip extension, and foot-floor angle at heel contact were assessed during overground walking. The energy cost of walking was determined from oxygen consumption data collected during treadmill walking. All measurements were collected at the participants' usual, self-selected walking speed. Results Fifty community-dwelling older adults with slow and variable gait participated. Hip extension, trunk flexion, and step width were factors related to the energy cost of walking. Hip extension, step width, and cadence were the only gait measures beyond age and gait speed that provided additional contributions to the variance of the energy cost, with mean R2 changes of .22, .12, and .07, respectively. Limitations Other factors not investigated in this study (interactions among variables, psychosocial factors, muscle strength [force-generating capacity], range of motion, body composition, and resting metabolic rate) may further explain the greater energy cost of walking in older adults with slow and variable gait. Conclusions Closer inspection of hip extension, step width, and cadence during physical therapy gait assessments may assist physical therapists in recognizing factors that contribute to the greater energy cost of walking in older adults. PMID:20488977

  18. Memantine improves spatial learning and memory impairments by regulating NGF signaling in APP/PS1 transgenic mice.

    PubMed

    Liu, M Y; Wang, S; Yao, W F; Zhang, Z J; Zhong, X; Sha, L; He, M; Zheng, Z H; Wei, M J

    2014-07-25

    Memantine (MEM) is used for improving the cognitive impairments of the patients suffering from Alzheimer's disease (AD) by multiple neuroprotective mechanisms. However, it is still not clear whether nerve growth factor (NGF) signaling is involved in the mechanisms of MEM. The present study investigated the neuroprotective effects of MEM treatment on the cognitive performance and amyloidosis in APP/PS1 transgenic mice, and disclosed the NGF-related mechanism of MEM. We found that MEM treatment improved the cognitive performance by decreasing the escape latency and path length in the navigation test, by shortening the duration in target quadrant and reducing the frequency to pass through the target in probe trial, and by prolonging the latency and decreasing the frequencies of entering the dark compartment in passive avoidance test. The over-expressions of Aβ(1-42) and amyloid precursor protein (APP) were also decreased in the brains of APP/PS1 mice. Interestingly, MEM treatment improved the decreased NGF levels in APP/PS1 mice. Furthermore, NGF/TrkA signaling was activated by increasing the phosphorylation levels of tyrosine kinase (TrkA), proto-oncogene serine/threonine-protein kinase, Raf1 (c-Raf), extracellular regulated protein kinases (ERK)1/2 and cAMP-response element binding protein (CREB) after MEM treatment. Simultaneously, MEM also inhibited NGF/p75(NTR) signaling via decreasing the cleavage substrate of p75(NTR), increasing the JNK2 phosphorylation and decreasing the levels of p53 and cleaved-caspase 3. Therefore, the dual-regulation on NGF signaling was attributed to the improvements of cognitive deficits and Aβ depositions in APP/PS1 mice. In conclusion, MEM treatment activated the NGF/TrkA signaling, and inhibited the p75(NTR) signaling in APP/PS1 mice to ameliorate the behavioral deficits and amyloidosis, indicating that NGF signaling was a new potential target of MEM treatment for AD therapy. PMID:24846616

  19. Data processing of remotely sensed airborne hyperspectral data using the Airborne Processing Library (APL): Geocorrection algorithm descriptions and spatial accuracy assessment

    NASA Astrophysics Data System (ADS)

    Warren, Mark A.; Taylor, Benjamin H.; Grant, Michael G.; Shutler, Jamie D.

    2014-03-01

    Remote sensing airborne hyperspectral data are routinely used for applications including algorithm development for satellite sensors, environmental monitoring and atmospheric studies. Single flight lines of airborne hyperspectral data are often in the region of tens of gigabytes in size. This means that a single aircraft can collect terabytes of remotely sensed hyperspectral data during a single year. Before these data can be used for scientific analyses, they need to be radiometrically calibrated, synchronised with the aircraft's position and attitude and then geocorrected. To enable efficient processing of these large datasets the UK Airborne Research and Survey Facility has recently developed a software suite, the Airborne Processing Library (APL), for processing airborne hyperspectral data acquired from the Specim AISA Eagle and Hawk instruments. The APL toolbox allows users to radiometrically calibrate, geocorrect, reproject and resample airborne data. Each stage of the toolbox outputs data in the common Band Interleaved Lines (BILs) format, which allows its integration with other standard remote sensing software packages. APL was developed to be user-friendly and suitable for use on a workstation PC as well as for the automated processing of the facility; to this end APL can be used under both Windows and Linux environments on a single desktop machine or through a Grid engine. A graphical user interface also exists. In this paper we describe the Airborne Processing Library software, its algorithms and approach. We present example results from using APL with an AISA Eagle sensor and we assess its spatial accuracy using data from multiple flight lines collected during a campaign in 2008 together with in situ surveyed ground control points.

  20. Spatial Variations in CO2 Mixing Ratios Over a Heterogenous Landscape - Linking Airborne Measurements With Remote Sensing Derived Biophysical Parameters

    NASA Astrophysics Data System (ADS)

    Choi, Y.; Vadrevu, K. P.; Vay, S. A.; Woo, J.

    2006-12-01

    North American terrestrial ecosystems are major sources and sinks of carbon. Precise measurement of atmospheric CO2 concentrations plays an important role in the development and testing of carbon cycle models quantifying the influence of terrestrial CO2 exchange on the North American carbon budget. During the summer 2004 Intercontinental Chemical Transport Experiment North America (INTEX-NA) campaign, regional scale in-situ measurements of atmospheric CO2 were made from the NASA DC-8 affording the opportunity to explore how land surface heterogeneity relates to the airborne observations utilizing remote-sensing data products and GIS-based methods. These 1 Hz data reveal the seasonal biospheric uptake of CO2 over portions of the U.S. continent, especially east of 90°W below 2 km, compared to higher mixing ratios over water as well as within the upper troposphere where well-mixed, aged air masses were sampled. In this study, we use several remote sensing derived biophysical parameters from the LANDSAT, NOAA AVHRR, and MODIS sensors to specify spatiotemporal patterns of land use cover and vegetation characteristics for linking the airborne measurements of CO2 data with terrestrial sources of carbon. Also, CO2 flux footprint outputs from a 3-D Lagrangian atmospheric model have been integrated with satellite remote sensing data to infer CO2 variations across heterogeneous landscapes. In examining the landscape mosaic utilizing these available tools, preliminary results suggest that the lowest CO2 mixing ratios observed during INTEX-NA were over agricultural fields in Illinois dominated by corn then secondarily soybean crops. Low CO2 concentrations are attributable to sampling during the peak growing season over such C4 plants as corn having a higher photosynthetic rate via the C4-dicarboxylic acid pathway of carbon fixation compared to C3 plants such as soybeans. In addition to LANDSAT derived land cover data, results from comparisons of the airborne CO2 observations

  1. Climate and climate change and infectious disease risk in Thailand: A spatial study of dengue hemorrhagic fever using GIS and remotely-sensed imagery

    NASA Astrophysics Data System (ADS)

    Kuzera, Kristopher

    The scientific community has widely accepted that climate plays a key role in the sustainability and transmission of many infectious diseases. Global climate change can potentially trigger the spread of disease into new regions and increase the intensity of disease in regions where it is endemic. This study explores the association between monthly conditions of climate change to changes in disease risk, emphasizing the potential spread of dengue fever due to climate change in Thailand. This study also develops techniques new to GIS and remote sensing that generate surfaces of daily minimum temperature toward identifying areas at greater transmission risk. Dengue fever expansion due to global warming is a serious concern for Thailand where warming temperatures may increase the size of the habitat of the disease-spreading vector, Aedes aegypti, particularly during cooler months when transmission is limited by environmental conditions. In this study, first, the association between past dengue hemorrhagic fever (DHF) and climate in Thailand is determined. Second, evidence of recent climate change is related to changes in DHF rates. Third, daily minimum temperature is derived from remote sensing toward identifying the spatial and temporal limitations of potential transmission risk. The results indicate that minimum temperature has recently experienced a rapid increase, particularly in the winter months when transmission is low. This is associated with a recent rise in winter DHF cases. As increasing minimum temperatures in these regions are anticipated to continue, we can expect dengue transmission rates to also increase throughout the year.

  2. Chronic Glucocorticoids Increase Hippocampal Vulnerability to Neurotoxicity under Conditions That Produce CA3 Dendritic Retraction But Fail to Impair Spatial Recognition Memory

    PubMed Central

    Conrad, Cheryl D.; McLaughlin, Katie J.; Harman, James S.; Foltz, Cainan; Wieczorek, Lindsay; Lightner, Elizabeth; Wright, Ryan L.

    2007-01-01

    We previously found that chronic stress conditions producing CA3 dendritic retraction and spatial memory deficits make the hippocampus vulnerable to the neurotoxin ibotenic acid (IBO). The purpose of this study was to determine whether exposure to chronic corticosterone (CORT) under conditions that produce CA3 dendritic retraction would enhance CA3 susceptibility to IBO. Male Sprague Dawley rats were chronically treated for 21 d with CORT in drinking water (400 μg/ml), and half were given daily injections of phenytoin (40 mg/kg), an antiepileptic drug that prevents CA3 dendritic retraction. Three days after treatments stopped, IBO was infused into the CA3 region. Conditions producing CA3 dendritic retraction (CORT and vehicle) exacerbated IBO-induced CA3 damage compared with conditions in which CA3 dendritic retraction was not observed (vehicle and vehicle, vehicle and phenytoin, CORT and phenytoin). Additionally, spatial recognition memory was assessed using the Y-maze, revealing that conditions producing CA3 dendritic retraction failed to impair spatial recognition memory. Furthermore, CORT levels in response to a potentially mild stressor (injection and Y-maze exposure) stayed at basal levels and failed to differ among key groups (vehicle and vehicle, CORT and vehicle, CORT and phenytoin), supporting the interpretations that CORT levels were unlikely to have been elevated during IBO infusion and that the neuroprotective actions of phenytoin were not through CORT alterations. These data are the first to show that conditions with prolonged glucocorticoid elevations leading to structural changes in hippocampal dendritic arbors can make the hippocampus vulnerable to neurotoxic challenges. These findings have significance for many disorders with elevated glucocorticoids that include depression, schizophrenia, Alzheimer’s disease, and Cushing’s disease. PMID:17670974

  3. Traumatic brain injury accelerates amyloid-β deposition and impairs spatial learning in the triple-transgenic mouse model of Alzheimer's disease.

    PubMed

    Shishido, Hajime; Kishimoto, Yasushi; Kawai, Nobuyuki; Toyota, Yasunori; Ueno, Masaki; Kubota, Takashi; Kirino, Yutaka; Tamiya, Takashi

    2016-08-26

    Several pathological and epidemiological studies have demonstrated a possible relationship between traumatic brain injury (TBI) and Alzheimer's disease (AD). However, the exact contribution of TBI to AD onset and progression is unclear. Hence, we examined AD-related histopathological changes and cognitive impairment after TBI in triple transgenic (3×Tg)-AD model mice. Five- to seven-month-old 3×Tg-AD model mice were subjected to either TBI by the weight-drop method or a sham treatment. In the 3×Tg-AD mice subjected to TBI, the spatial learning was not significantly different 7 days after TBI compared to that of the sham-treated 3×Tg-AD mice. However, 28 days after TBI, the 3×Tg-AD mice exhibited significantly lower spatial learning than the sham-treated 3×Tg-AD mice. Correspondingly, while a few amyloid-β (Aβ) plaques were observed in both sham-treated and TBI-treated 3×Tg-AD mouse hippocampus 7 days after TBI, the Aβ deposition was significantly greater in 3×Tg-AD mice 28 days after TBI. Thus, we demonstrated that TBI induced a significant increase in hippocampal Aβ deposition 28 days after TBI compared to that of the control animals, which was associated with worse spatial learning ability in 3×Tg-AD mice. The present study suggests that TBI could be a risk factor for accelerated AD progression, particularly when genetic and hereditary predispositions are involved. PMID:27373531

  4. Developmental treatment with the dopamine D2/3 agonist quinpirole selectively impairs spatial learning in the Morris water maze.

    PubMed

    Vorhees, Charles V; Johnson, Holly L; Burns, Lindsey N; Williams, Michael T

    2009-01-01

    Developmental exposure to the dopamine D2/3 receptor agonist quinpirole is reported to induce D2 priming, impair Morris water maze performance, reduce acoustic startle prepulse inhibition (PPI), and alter locomotor activity. We treated rats from postnatal days 1-21