Spatiotemporally Representative and Cost-Efficient Sampling Design for Validation Activities in Wanglang Experimental Site

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Gaofei Yin

2017-11-01

Full Text Available Spatiotemporally representative Elementary Sampling Units (ESUs are required for capturing the temporal variations in surface spatial heterogeneity through field measurements. Since inaccessibility often coexists with heterogeneity, a cost-efficient sampling design is mandatory. We proposed a sampling strategy to generate spatiotemporally representative and cost-efficient ESUs based on the conditioned Latin hypercube sampling scheme. The proposed strategy was constrained by multi-temporal Normalized Difference Vegetation Index (NDVI imagery, and the ESUs were limited within a sampling feasible region established based on accessibility criteria. A novel criterion based on the Overlapping Area (OA between the NDVI frequency distribution histogram from the sampled ESUs and that from the entire study area was used to assess the sampling efficiency. A case study in Wanglang National Nature Reserve in China showed that the proposed strategy improves the spatiotemporally representativeness of sampling (mean annual OA = 74.7% compared to the single-temporally constrained (OA = 68.7% and the random sampling (OA = 63.1% strategies. The introduction of the feasible region constraint significantly reduces in-situ labour-intensive characterization necessities at expenses of about 9% loss in the spatiotemporal representativeness of the sampling. Our study will support the validation activities in Wanglang experimental site providing a benchmark for locating the nodes of automatic observation systems (e.g., LAINet which need a spatially distributed and temporally fixed sampling design.

Estimating Activity Patterns Using Spatio-temporal Data of Cellphone Networks

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Zahedi Seyedmostafa

2016-01-01

Full Text Available The tendency towards using activity-based models to predict trip demand has increased dramatically over recent years, but these models have suffered insufficient data for calibration. This paper discusses ways to process the cellphone spatio-temporal data in a manner that makes it comprehensible for traffic interpretations and proposes methods on how to infer urban mobility and activity patterns from the aforementioned data. Movements of each subscriber is described by a sequence of stays and trips and each stay is labeled by an activity. The type of activities are estimated using features such as land use, duration of stay, frequency of visit, arrival time to that activity and its distance from home. Finally, the chains of trips are identified and different patterns that citizens follow to participate in activities are determined. The data comprises 144 million records of the location of 300,000 citizens of Shiraz at five-minute intervals.

Determination of aberration center of Ronchigram for automated aberration correctors in scanning transmission electron microscopy

Energy Technology Data Exchange (ETDEWEB)

Sannomiya, Takumi, E-mail: sannomiya@mtl.titech.ac.jp [Tokyo Institute of Technology, Ookayama, Tokyo (Japan); Sawada, Hidetaka; Nakamichi, Tomohiro; Hosokawa, Fumio [JEOL Limited, Akishima, Tokyo (Japan); Nakamura, Yoshio; Tanishiro, Yasumasa; Takayanagi, Kunio [Tokyo Institute of Technology, Ookayama, Tokyo (Japan)

2013-12-15

A generic method to determine the aberration center is established, which can be utilized for aberration calculation and axis alignment for aberration corrected electron microscopes. In this method, decentering induced secondary aberrations from inherent primary aberrations are minimized to find the appropriate axis center. The fitness function to find the optimal decentering vector for the axis was defined as a sum of decentering induced secondary aberrations with properly distributed weight values according to the aberration order. Since the appropriate decentering vector is determined from the aberration values calculated at an arbitrary center axis, only one aberration measurement is in principle required to find the center, resulting in /very fast center search. This approach was tested for the Ronchigram based aberration calculation method for aberration corrected scanning transmission electron microscopy. Both in simulation and in experiments, the center search was confirmed to work well although the convergence to find the best axis becomes slower with larger primary aberrations. Such aberration center determination is expected to fully automatize the aberration correction procedures, which used to require pre-alignment of experienced users. This approach is also applicable to automated aperture positioning. - Highlights: • A generic method to determine the aberration center is established for (S)TEM. • Decentering induced secondary aberrations are utilized to find the center. • The method is tested on Ronchigrams both in simulation and experiment. • Proper weighting of the aberration gives a good convergence. • Larger primary aberration results in a slower convergence.

Automated detection of qualitative spatio-temporal features in electrocardiac activation maps.

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Ironi, Liliana; Tentoni, Stefania

2007-02-01

This paper describes a piece of work aiming at the realization of a tool for the automated interpretation of electrocardiac maps. Such maps can capture a number of electrical conduction pathologies, such as arrhytmia, that can be missed by the analysis of traditional electrocardiograms. But, their introduction into the clinical practice is still far away as their interpretation requires skills that belongs to very few experts. Then, an automated interpretation tool would bridge the gap between the established research outcome and clinical practice with a consequent great impact on health care. Qualitative spatial reasoning can play a crucial role in the identification of spatio-temporal patterns and salient features that characterize the heart electrical activity. We adopted the spatial aggregation (SA) conceptual framework and an interplay of numerical and qualitative information to extract features from epicardial maps, and to make them available for reasoning tasks. Our focus is on epicardial activation isochrone maps as they are a synthetic representation of spatio-temporal aspects of the propagation of the electrical excitation. We provide a computational SA-based methodology to extract, from 3D epicardial data gathered over time, (1) the excitation wavefront structure, and (2) the salient features that characterize wavefront propagation and visually correspond to specific geometric objects. The proposed methodology provides a robust and efficient way to identify salient pieces of information in activation time maps. The hierarchical structure of the abstracted geometric objects, crucial in capturing the prominent information, facilitates the definition of general rules necessary to infer the correlation between pathophysiological patterns and wavefront structure and propagation.

NOTCH1 Is Aberrantly Activated in Chronic Lymphocytic Leukemia Hematopoietic Stem Cells

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Mauro Di Ianni

2018-04-01

Full Text Available To investigate chronic lymphocytic leukemia (CLL-initiating cells, we assessed NOTCH1 mutation/expression in hematopoietic stem cells (HSCs. In NOTCH1-mutated CLL, we detected subclonal mutations in 57% CD34+/CD38− HSCs. NOTCH1 mutation was present in 66% CD34+/CD38+ progenitor cells displaying an increased mutational burden compared to HSCs. Flow cytometric analysis revealed significantly higher NOTCH1 activation in CD34+/CD38− and CD34+/CD38+ cells from CLL patients, regardless NOTCH1 mutation compared to healthy donors. Activated NOTCH1 resulted in overexpression of the NOTCH1 target c-MYC. We conclude that activated NOTCH1 is an early event in CLL that may contribute to aberrant HSCs in this disease.

NOTCH1 Is Aberrantly Activated in Chronic Lymphocytic Leukemia Hematopoietic Stem Cells.

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Di Ianni, Mauro; Baldoni, Stefano; Del Papa, Beatrice; Aureli, Patrizia; Dorillo, Erica; De Falco, Filomena; Albi, Elisa; Varasano, Emanuela; Di Tommaso, Ambra; Giancola, Raffaella; Accorsi, Patrizia; Rotta, Gianluca; Rompietti, Chiara; Silva Barcelos, Estevão Carlos; Campese, Antonio Francesco; Di Bartolomeo, Paolo; Screpanti, Isabella; Rosati, Emanuela; Falzetti, Franca; Sportoletti, Paolo

2018-01-01

To investigate chronic lymphocytic leukemia (CLL)-initiating cells, we assessed NOTCH1 mutation/expression in hematopoietic stem cells (HSCs). In NOTCH1- mutated CLL, we detected subclonal mutations in 57% CD34+/CD38- HSCs. NOTCH1 mutation was present in 66% CD34+/CD38+ progenitor cells displaying an increased mutational burden compared to HSCs. Flow cytometric analysis revealed significantly higher NOTCH1 activation in CD34+/CD38- and CD34+/CD38+ cells from CLL patients, regardless NOTCH1 mutation compared to healthy donors. Activated NOTCH1 resulted in overexpression of the NOTCH1 target c-MYC. We conclude that activated NOTCH1 is an early event in CLL that may contribute to aberrant HSCs in this disease.

Differentiated Effects of Sensory Activities as Abolishing Operations via Non-Contingent Reinforcement on Academic and Aberrant Behavior

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Mancil, G. Richmond; Haydon, Todd; Boman, Marty

2016-01-01

The purpose of the study was to evaluate the effectiveness of sensory activities used as antecedent interventions on the percentage correct on academic tasks and rate of aberrant behavior in three elementary aged children with Autism Spectrum Disorders (ASD). Study activities were conducted in an after school program for children with ASD where…

Possible mechanisms of chromosome aberrations. 2. Formation of aberrations after UV-irradiation

International Nuclear Information System (INIS)

Lebedeva, L.I.

1982-01-01

One of mechanisms of chromosome aberrations after UV-radiation of animal cells initiated by thymine dimerization from different dna threads (by cross joints) and finished in mitosis metaphase is discussed. The model of aberration formation, taking a count of peculiarities of chromosome ansate structure and predicting the important role of chromosome isolation during mitosis in realization of structural aberrations, is suggested. An attempt to present aberration formation under conditions of exact repair is the distinguishing feature of the model

Spatiotemporal dynamics of word retrieval in speech production revealed by cortical high-frequency band activity.

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Riès, Stephanie K; Dhillon, Rummit K; Clarke, Alex; King-Stephens, David; Laxer, Kenneth D; Weber, Peter B; Kuperman, Rachel A; Auguste, Kurtis I; Brunner, Peter; Schalk, Gerwin; Lin, Jack J; Parvizi, Josef; Crone, Nathan E; Dronkers, Nina F; Knight, Robert T

2017-06-06

Word retrieval is core to language production and relies on complementary processes: the rapid activation of lexical and conceptual representations and word selection, which chooses the correct word among semantically related competitors. Lexical and conceptual activation is measured by semantic priming. In contrast, word selection is indexed by semantic interference and is hampered in semantically homogeneous (HOM) contexts. We examined the spatiotemporal dynamics of these complementary processes in a picture naming task with blocks of semantically heterogeneous (HET) or HOM stimuli. We used electrocorticography data obtained from frontal and temporal cortices, permitting detailed spatiotemporal analysis of word retrieval processes. A semantic interference effect was observed with naming latencies longer in HOM versus HET blocks. Cortical response strength as indexed by high-frequency band (HFB) activity (70-150 Hz) amplitude revealed effects linked to lexical-semantic activation and word selection observed in widespread regions of the cortical mantle. Depending on the subsecond timing and cortical region, HFB indexed semantic interference (i.e., more activity in HOM than HET blocks) or semantic priming effects (i.e., more activity in HET than HOM blocks). These effects overlapped in time and space in the left posterior inferior temporal gyrus and the left prefrontal cortex. The data do not support a modular view of word retrieval in speech production but rather support substantial overlap of lexical-semantic activation and word selection mechanisms in the brain.

Low-energy foil aberration corrector

International Nuclear Information System (INIS)

Aken, R.H. van; Hagen, C.W.; Barth, J.E.; Kruit, P.

2002-01-01

A spherical and chromatic aberration corrector for electron microscopes is proposed, consisting of a thin foil sandwiched between two apertures. The electrons are retarded at the foil to almost zero energy, so that they can travel ballistically through the foil. It is shown that such a low-voltage corrector has a negative spherical aberration for not too large distances between aperture and foil, as well as a negative chromatic aberration. For various distances the third- and fifth-order spherical aberration coefficients and the first- and second-order chromatic aberration coefficients are calculated using ray tracing. Provided that the foils have sufficient electron transmission the corrector is able to correct the third-order spherical aberration and the first-order chromatic aberration of a typical low-voltage scanning electron microscope. Preliminary results show that the fifth-order spherical aberration and the second-order chromatic aberration can be kept sufficiently low

Active sensing via movement shapes spatiotemporal patterns of sensory feedback.

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Stamper, Sarah A; Roth, Eatai; Cowan, Noah J; Fortune, Eric S

2012-05-01

Previous work has shown that animals alter their locomotor behavior to increase sensing volumes. However, an animal's own movement also determines the spatial and temporal dynamics of sensory feedback. Because each sensory modality has unique spatiotemporal properties, movement has differential and potentially independent effects on each sensory system. Here we show that weakly electric fish dramatically adjust their locomotor behavior in relation to changes of modality-specific information in a task in which increasing sensory volume is irrelevant. We varied sensory information during a refuge-tracking task by changing illumination (vision) and conductivity (electroreception). The gain between refuge movement stimuli and fish tracking responses was functionally identical across all sensory conditions. However, there was a significant increase in the tracking error in the dark (no visual cues). This was a result of spontaneous whole-body oscillations (0.1 to 1 Hz) produced by the fish. These movements were costly: in the dark, fish swam over three times further when tracking and produced more net positive mechanical work. The magnitudes of these oscillations increased as electrosensory salience was degraded via increases in conductivity. In addition, tail bending (1.5 to 2.35 Hz), which has been reported to enhance electrosensory perception, occurred only during trials in the dark. These data show that both categories of movements - whole-body oscillations and tail bends - actively shape the spatiotemporal dynamics of electrosensory feedback.

Spatio-temporal manipulation of small GTPase activity at subcellular level and on timescale of seconds in living cells.

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DeRose, Robert; Pohlmeyer, Christopher; Umeda, Nobuhiro; Ueno, Tasuku; Nagano, Tetsuo; Kuo, Scot; Inoue, Takanari

2012-03-09

Dynamic regulation of the Rho family of small guanosine triphosphatases (GTPases) with great spatiotemporal precision is essential for various cellular functions and events(1, 2). Their spatiotemporally dynamic nature has been revealed by visualization of their activity and localization in real time(3). In order to gain deeper understanding of their roles in diverse cellular functions at the molecular level, the next step should be perturbation of protein activities at a precise subcellular location and timing. To achieve this goal, we have developed a method for light-induced, spatio-temporally controlled activation of small GTPases by combining two techniques: (1) rapamycin-induced FKBP-FRB heterodimerization and (2) a photo-caging method of rapamycin. With the use of rapamycin-mediated FKBP-FRB heterodimerization, we have developed a method for rapidly inducible activation or inactivation of small GTPases including Rac(4), Cdc42(4), RhoA(4) and Ras(5), in which rapamycin induces translocation of FKBP-fused GTPases, or their activators, to the plasma membrane where FRB is anchored. For coupling with this heterodimerization system, we have also developed a photo-caging system of rapamycin analogs. A photo-caged compound is a small molecule whose activity is suppressed with a photocleavable protecting group known as a caging group. To suppress heterodimerization activity completely, we designed a caged rapamycin that is tethered to a macromolecule such that the resulting large complex cannot cross the plasma membrane, leading to virtually no background activity as a chemical dimerizer inside cells(6). Figure 1 illustrates a scheme of our system. With the combination of these two systems, we locally recruited a Rac activator to the plasma membrane on a timescale of seconds and achieved light-induced Rac activation at the subcellular level(6).

Chromosome aberrations as a biological dosimeter in Thorotrast patients: dosimetric problems

International Nuclear Information System (INIS)

Kemmer, W.; Steinstraesser, A.; Muth, H.

1979-01-01

The results of chromosome aberration analyses in 68 Thorotrast patients are discussed. In all patients dicentric chromosome aberrations were found but the chromosome aberration rate neither corresponds with the calculated whole body activity or the estimated absorbed dose in the organs of the RHS nor with the radium-224-equivalent value calculated from the radon-220 activity measured in the expired air. From x-ray examinations and histologic studies of lymph nodes the conclusion is drawn that the microdose absorbed from one lymphocyte is not in relation to the mean absorbed RHS dose, calculated from biophysical measurements

The Importance of Spatiotemporal Information in Biological Motion Perception: White Noise Presented with a Step-like Motion Activates the Biological Motion Area.

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Callan, Akiko; Callan, Daniel; Ando, Hiroshi

2017-02-01

Humans can easily recognize the motion of living creatures using only a handful of point-lights that describe the motion of the main joints (biological motion perception). This special ability to perceive the motion of animate objects signifies the importance of the spatiotemporal information in perceiving biological motion. The posterior STS (pSTS) and posterior middle temporal gyrus (pMTG) region have been established by many functional neuroimaging studies as a locus for biological motion perception. Because listening to a walking human also activates the pSTS/pMTG region, the region has been proposed to be supramodal in nature. In this study, we investigated whether the spatiotemporal information from simple auditory stimuli is sufficient to activate this biological motion area. We compared spatially moving white noise, having a running-like tempo that was consistent with biological motion, with stationary white noise. The moving-minus-stationary contrast showed significant differences in activation of the pSTS/pMTG region. Our results suggest that the spatiotemporal information of the auditory stimuli is sufficient to activate the biological motion area.

Imaging the spatio-temporal dynamics of supragranular activity in the rat somatosensory cortex in response to stimulation of the paws.

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M L Morales-Botello

Full Text Available We employed voltage-sensitive dye (VSD imaging to investigate the spatio-temporal dynamics of the responses of the supragranular somatosensory cortex to stimulation of the four paws in urethane-anesthetized rats. We obtained the following main results. (1 Stimulation of the contralateral forepaw evoked VSD responses with greater amplitude and smaller latency than stimulation of the contralateral hindpaw, and ipsilateral VSD responses had a lower amplitude and greater latency than contralateral responses. (2 While the contralateral stimulation initially activated only one focus, the ipsilateral stimulation initially activated two foci: one focus was typically medial to the focus activated by contralateral stimulation and was stereotaxically localized in the motor cortex; the other focus was typically posterior to the focus activated by contralateral stimulation and was stereotaxically localized in the somatosensory cortex. (3 Forepaw and hindpaw somatosensory stimuli activated large areas of the sensorimotor cortex, well beyond the forepaw and hindpaw somatosensory areas of classical somatotopic maps, and forepaw stimuli activated larger cortical areas with greater activation velocity than hindpaw stimuli. (4 Stimulation of the forepaw and hindpaw evoked different cortical activation dynamics: forepaw responses displayed a clear medial directionality, whereas hindpaw responses were much more uniform in all directions. In conclusion, this work offers a complete spatio-temporal map of the supragranular VSD cortical activation in response to stimulation of the paws, showing important somatotopic differences between contralateral and ipsilateral maps as well as differences in the spatio-temporal activation dynamics in response to forepaw and hindpaw stimuli.

Spatio-Temporal Rule Mining

DEFF Research Database (Denmark)

Gidofalvi, Gyozo; Pedersen, Torben Bach

2005-01-01

Recent advances in communication and information technology, such as the increasing accuracy of GPS technology and the miniaturization of wireless communication devices pave the road for Location-Based Services (LBS). To achieve high quality for such services, spatio-temporal data mining techniques...... are needed. In this paper, we describe experiences with spatio-temporal rule mining in a Danish data mining company. First, a number of real world spatio-temporal data sets are described, leading to a taxonomy of spatio-temporal data. Second, the paper describes a general methodology that transforms...... the spatio-temporal rule mining task to the traditional market basket analysis task and applies it to the described data sets, enabling traditional association rule mining methods to discover spatio-temporal rules for LBS. Finally, unique issues in spatio-temporal rule mining are identified and discussed....

Angstrom analysis with dynamic in-situ aberration corrected electron microscopy

International Nuclear Information System (INIS)

Gai, P L; Boyes, E D

2010-01-01

Following the pioneering development of atomic resolution in-situ environmental TEM (ETEM) for direct probing of gas-solid reactions, recent developments are presented of dynamic real time in-situ studies at the Angstrom level in an aberration corrected electron microscope. The in-situ data from Pt-Pd nanoparticles on carbon with the corresponding FFT/optical diffractogram (OD) illustrate an achieved resolution of 0 C and higher, in a double aberration corrected JEOL 2200 FS TEM/STEM employing a wider gap objective pole piece and gas tolerant TMP column pumping system. Direct observations of dynamic biofuel catalysts under controlled calcinations conditions and quantified with catalytic reactivity and physico-chemical studies show the benefits in-situ aberration correction in unveiling the evolution of surface active sites necessary for the development efficient heterogeneous catalysts. The new results open up opportunities for dynamic studies of materials in an aberration corrected environment and direct future development activities.

The impact of physical activity on the level of chromosome aberrations

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Šošić Gordana M.

2015-01-01

Full Text Available During the lifetime, people are constantly exposed to the chemicals and agents of exogenic and endogenic sources, which through reaction with a molecule of DNA can cause the damage of genomes and their instability. The formation of micronuclei is a consequence of chromosomal aberrations caused by the influence of different genetic and environmental factors. Micronuclei are cytoplasmic chromatin masses that look like small nuclei and can originate from whole or parts of chromosomes. Micronucleus test ( MN test is used to detect genotoxic effects of various chemical , physical or biological mutagens, as well as the test for determination of chromosomal instability in a variety of cell types. Micronucleus frequency is directly proportional to the degree of chromosomal aberrations. It has been shown that genome damage may occur as a result of environmental exposure to genotoxins and medical procedures, due to deficiency of micronutrients and under the influence of various lifestyles and genetic factors. Unbalanced diet, lack of physical exercise, lack of sleep and overwork contribute significantly to increased frequency of micronuclei. It was also shown that strenuous exercise causes DNA damage, which results in the formation of micronuclei. As a professional athlete conduct highly Intensive physical training, these populations are at risk for the development of genomic instability and carcinogenesis. A healthy lifestyle, the optimal intake of antioxidants and regular moderate physical activity significantly reduced the frequency of micronuclei, and contribute to the stability of the genome.

Optical traps with geometric aberrations

International Nuclear Information System (INIS)

Roichman, Yael; Waldron, Alex; Gardel, Emily; Grier, David G.

2006-01-01

We assess the influence of geometric aberrations on the in-plane performance of optical traps by studying the dynamics of trapped colloidal spheres in deliberately distorted holographic optical tweezers. The lateral stiffness of the traps turns out to be insensitive to moderate amounts of coma, astigmatism, and spherical aberration. Moreover holographic aberration correction enables us to compensate inherent shortcomings in the optical train, thereby adaptively improving its performance. We also demonstrate the effects of geometric aberrations on the intensity profiles of optical vortices, whose readily measured deformations suggest a method for rapidly estimating and correcting geometric aberrations in holographic trapping systems

Dynamic decomposition of spatiotemporal neural signals.

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Luca Ambrogioni

2017-05-01

Full Text Available Neural signals are characterized by rich temporal and spatiotemporal dynamics that reflect the organization of cortical networks. Theoretical research has shown how neural networks can operate at different dynamic ranges that correspond to specific types of information processing. Here we present a data analysis framework that uses a linearized model of these dynamic states in order to decompose the measured neural signal into a series of components that capture both rhythmic and non-rhythmic neural activity. The method is based on stochastic differential equations and Gaussian process regression. Through computer simulations and analysis of magnetoencephalographic data, we demonstrate the efficacy of the method in identifying meaningful modulations of oscillatory signals corrupted by structured temporal and spatiotemporal noise. These results suggest that the method is particularly suitable for the analysis and interpretation of complex temporal and spatiotemporal neural signals.

Spatiotemporal Data Mining: A Computational Perspective

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Shashi Shekhar

2015-10-01

Full Text Available Explosive growth in geospatial and temporal data as well as the emergence of new technologies emphasize the need for automated discovery of spatiotemporal knowledge. Spatiotemporal data mining studies the process of discovering interesting and previously unknown, but potentially useful patterns from large spatiotemporal databases. It has broad application domains including ecology and environmental management, public safety, transportation, earth science, epidemiology, and climatology. The complexity of spatiotemporal data and intrinsic relationships limits the usefulness of conventional data science techniques for extracting spatiotemporal patterns. In this survey, we review recent computational techniques and tools in spatiotemporal data mining, focusing on several major pattern families: spatiotemporal outlier, spatiotemporal coupling and tele-coupling, spatiotemporal prediction, spatiotemporal partitioning and summarization, spatiotemporal hotspots, and change detection. Compared with other surveys in the literature, this paper emphasizes the statistical foundations of spatiotemporal data mining and provides comprehensive coverage of computational approaches for various pattern families. ISPRS Int. J. Geo-Inf. 2015, 4 2307 We also list popular software tools for spatiotemporal data analysis. The survey concludes with a look at future research needs.

Parallel optical control of spatiotemporal neuronal spike activity using high-frequency digital light processingtechnology

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Jason eJerome

2011-08-01

Full Text Available Neurons in the mammalian neocortex receive inputs from and communicate back to thousands of other neurons, creating complex spatiotemporal activity patterns. The experimental investigation of these parallel dynamic interactions has been limited due to the technical challenges of monitoring or manipulating neuronal activity at that level of complexity. Here we describe a new massively parallel photostimulation system that can be used to control action potential firing in in vitro brain slices with high spatial and temporal resolution while performing extracellular or intracellular electrophysiological measurements. The system uses Digital-Light-Processing (DLP technology to generate 2-dimensional (2D stimulus patterns with >780,000 independently controlled photostimulation sites that operate at high spatial (5.4 µm and temporal (>13kHz resolution. Light is projected through the quartz-glass bottom of the perfusion chamber providing access to a large area (2.76 x 2.07 mm2 of the slice preparation. This system has the unique capability to induce temporally precise action potential firing in large groups of neurons distributed over a wide area covering several cortical columns. Parallel photostimulation opens up new opportunities for the in vitro experimental investigation of spatiotemporal neuronal interactions at a broad range of anatomical scales.

Mask-induced aberration in EUV lithography

Science.gov (United States)

Nakajima, Yumi; Sato, Takashi; Inanami, Ryoichi; Nakasugi, Tetsuro; Higashiki, Tatsuhiko

2009-04-01

We estimated aberrations using Zernike sensitivity analysis. We found the difference of the tolerated aberration with line direction for illumination. The tolerated aberration of perpendicular line for illumination is much smaller than that of parallel line. We consider this difference to be attributable to the mask 3D effect. We call it mask-induced aberration. In the case of the perpendicular line for illumination, there was a difference in CD between right line and left line without aberration. In this report, we discuss the possibility of pattern formation in NA 0.25 generation EUV lithography tool. In perpendicular pattern for EUV light, the dominant part of aberration is mask-induced aberration. In EUV lithography, pattern correction based on the mask topography effect will be more important.

Building spatio-temporal database model based on ontological approach using relational database environment

International Nuclear Information System (INIS)

Mahmood, N.; Burney, S.M.A.

2017-01-01

Everything in this world is encapsulated by space and time fence. Our daily life activities are utterly linked and related with other objects in vicinity. Therefore, a strong relationship exist with our current location, time (including past, present and future) and event through with we are moving as an object also affect our activities in life. Ontology development and its integration with database are vital for the true understanding of the complex systems involving both spatial and temporal dimensions. In this paper we propose a conceptual framework for building spatio-temporal database model based on ontological approach. We have used relational data model for modelling spatio-temporal data content and present our methodology with spatio-temporal ontological accepts and its transformation into spatio-temporal database model. We illustrate the implementation of our conceptual model through a case study related to cultivated land parcel used for agriculture to exhibit the spatio-temporal behaviour of agricultural land and related entities. Moreover, it provides a generic approach for designing spatiotemporal databases based on ontology. The proposed model is capable to understand the ontological and somehow epistemological commitments and to build spatio-temporal ontology and transform it into a spatio-temporal data model. Finally, we highlight the existing and future research challenges. (author)

Phytochemicals attenuating aberrant activation of β-catenin in cancer cells.

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Dan Wang

Full Text Available Phytochemicals are a rich source of chemoprevention agents but their effects on modulating the Wnt/β-catenin signaling pathway have remained largely uninvestigated. Aberrantly activated Wnt signaling can result in the abnormal stabilization of β-catenin, a key causative step in a broad spectrum of cancers. Here we report the modulation of lithium chloride-activated canonical Wnt/β-catenin signaling by phytochemicals that have antioxidant, anti-inflammatory or chemopreventive properties. The compounds were first screened with a cervical cancer-derived stable Wnt signaling reporter HeLa cell line. Positive hits were subsequently evaluated for β-catenin degradation, suppression of β-catenin nuclear localization and down-regulation of downstream oncogenic targets of Wnt/β-catenin pathway. Our study shows a novel degradation path of β-catenin protein in HeLa cells by Avenanthramide 2p (a polyphenol and Triptolide (a diterpene triepoxide, respectively from oats and a Chinese medicinal plant. The findings present Avenanthramide 2p as a potential chemopreventive dietary compound that merits further study using in vivo models of cancers; they also provide a new perspective on the mechanism of action of Triptolide.

Camera processing with chromatic aberration.

Science.gov (United States)

Korneliussen, Jan Tore; Hirakawa, Keigo

2014-10-01

Since the refractive index of materials commonly used for lens depends on the wavelengths of light, practical camera optics fail to converge light to a single point on an image plane. Known as chromatic aberration, this phenomenon distorts image details by introducing magnification error, defocus blur, and color fringes. Though achromatic and apochromatic lens designs reduce chromatic aberration to a degree, they are complex and expensive and they do not offer a perfect correction. In this paper, we propose a new postcapture processing scheme designed to overcome these problems computationally. Specifically, the proposed solution is comprised of chromatic aberration-tolerant demosaicking algorithm and post-demosaicking chromatic aberration correction. Experiments with simulated and real sensor data verify that the chromatic aberration is effectively corrected.

Aberration compensation using a spatial light modulator LCD

International Nuclear Information System (INIS)

Amezquita, R; Rincon, O; Torres, Y M

2011-01-01

The dynamic correction of aberrations introduced in optical systems have been a widely discussed topic in the past 10 years. Adaptive optics is the most important developed field where the Shack-Hartmann sensors and deformable mirrors are used for the measurement and correction of wavefronts. In this paper, an interferometric set-up which uses a Spatial Light Modulator (SLM) as an active element is proposed. Using this SLM a procedure for the compensation of all phase aberrations present in the experimental setup is shown.

Spatiotemporal organization of alpha-motoneuron activity in the human spinal cord during different gaits and gait transitions.

Science.gov (United States)

Ivanenko, Y P; Cappellini, G; Poppele, R E; Lacquaniti, F

2008-06-01

Here we studied the spatiotemporal organization of motoneuron (MN) activity during different human gaits. We recorded the electromyographic (EMG) activity patterns in 32 ipsilateral limb and trunk muscles from normal subjects while running and walking on a treadmill (3-12 km/h). In addition, we recorded backward walking and skipping, a distinct human gait that comprises the features of both walking and running. We mapped the recorded EMG activity patterns onto the spinal cord in approximate rostrocaudal locations of the MN pools. The activation of MNs tends to occur in bursts and be segregated by spinal segment in a gait-specific manner. In particular, sacral and cervical activation timings were clearly gait-dependent. Swing-related activity constituted an appreciable fraction (> 30%) of the total MN activity of leg muscles. Locomoting at non-preferred speeds (running and walking at 5 and 9 km/h, respectively) showed clear differences relative to preferred speeds. Running at low speeds was characterized by wider sacral activation. Walking at high non-preferred speeds was accompanied by an 'atypical' locus of activation in the upper lumbar spinal cord during late stance and by a drastically increased activation of lumbosacral segments. The latter findings suggest that the optimal speed of gait transitions may be related to an optimal intensity of the total MN activity, in addition to other factors previously described. The results overall support the idea of flexibility and adaptability of spatiotemporal activity in the spinal circuitry with constraints on the temporal functional connectivity of hypothetical pulsatile burst generators.

Repressive but not activating epigenetic modifications are aberrant on the inactive X chromosome in live cloned cattle.

Science.gov (United States)

Geng-Sheng, Cao; Yu, Gao; Kun, Wang; Fang-Rong, Ding; Ning, Li

2009-08-01

X inactivation is the process of a chromosome-wide silencing of the majority of genes on the X chromosome during early mammalian development. This process may be aberrant in cloned animals. Here we show that repressive modifications, such as methylation of DNA, and the presence of methylated histones, H3K9me2 and H3K27me3, exhibit distinct aberrance on the inactive X chromosome in live clones. In contrast, H3K4me3, an active gene marker, is obviously missing from the inactive X chromosome in all cattle studied. This suggests that the disappearance of active histone modifications (H3K4me3) seems to be more important for X inactivation than deposition of marks associated with heterochromatin (DNA methylation, H3K27me3 and H3K9me2). It also implies that even apparently normal clones may have subtle abnormalities in repressive, but not activating epigenetic modifications on the inactive X when they survive to term. We also found that the histone H3 methylations were enriched and co-localized at q21-31 of the active X chromosome, which may be associated with an abundance of LINE1 repeat elements. © 2009 The Authors. Journal compilation © 2009 Japanese Society of Developmental Biologists.

Spatiotemporal Wave Patterns: Information Dynamics

Energy Technology Data Exchange (ETDEWEB)

Mikhail Rabinovich; Lev Tsimring

2006-01-20

Pattern formation has traditionally been studied in non-equilibrium physics from the viewpoint of describing the basic structures and their interactions. While this is still an important area of research, the emphasis in the last few years has shifted towards analysis of specific properties of patterns in various complex media. For example, diverse and unexpected phenomena occur in neuro-like media that are characterized by highly non-trivial local dynamics. We carried out an active research program on analysis of spatio-temporal patterns in various physical systems (convection, oscillating fluid layer, soap film), as well as in neuro-like media, with an emphasis on informational aspects of the dynamics. Nonlinear nonequilibrium media and their discrete analogs have a unique ability to represent, memorize, and process the information contained in spatio-temporal patterns. Recent neurophysiological experiments demonstrated a certain universality of spatio-temporal representation of information by neural ensembles. Information processing is also revealed in the spatio-temporal dynamics of cellular patterns in nonequilibrium media. It is extremely important for many applications to study the informational aspects of these dynamics, including the origins and mechanisms of information generation, propagation and storage. Some of our results are: the discovery of self-organization of periodically oscillatory patterns in chaotic heterogeneous media; the analysis of the propagation of the information along a chaotic media as function of the entropy of the signal; the analysis of wave propagation in discrete non-equilibrium media with autocatalytic properties, which simulates the calcium dynamics in cellular membranes. Based on biological experiments we suggest the mechanism by which the spatial sensory information is transferred into the spatio-temporal code in the neural media. We also found a new mechanism of self-pinning in cellular structures and the related phenomenon

Attention training improves aberrant neural dynamics during working memory processing in veterans with PTSD.

Science.gov (United States)

McDermott, Timothy J; Badura-Brack, Amy S; Becker, Katherine M; Ryan, Tara J; Bar-Haim, Yair; Pine, Daniel S; Khanna, Maya M; Heinrichs-Graham, Elizabeth; Wilson, Tony W

2016-12-01

Posttraumatic stress disorder (PTSD) is associated with executive functioning deficits, including disruptions in working memory (WM). Recent studies suggest that attention training reduces PTSD symptomatology, but the underlying neural mechanisms are unknown. We used high-density magnetoencephalography (MEG) to evaluate whether attention training modulates brain regions serving WM processing in PTSD. Fourteen veterans with PTSD completed a WM task during a 306-sensor MEG recording before and after 8 sessions of attention training treatment. A matched comparison sample of 12 combat-exposed veterans without PTSD completed the same WM task during a single MEG session. To identify the spatiotemporal dynamics, each group's data were transformed into the time-frequency domain, and significant oscillatory brain responses were imaged using a beamforming approach. All participants exhibited activity in left hemispheric language areas consistent with a verbal WM task. Additionally, veterans with PTSD and combat-exposed healthy controls each exhibited oscillatory responses in right hemispheric homologue regions (e.g., right Broca's area); however, these responses were in opposite directions. Group differences in oscillatory activity emerged in the theta band (4-8 Hz) during encoding and in the alpha band (9-12 Hz) during maintenance and were significant in right prefrontal and right supramarginal and inferior parietal regions. Importantly, following attention training, these significant group differences were reduced or eliminated. This study provides initial evidence that attention training improves aberrant neural activity in brain networks serving WM processing.

Correlations between corneal and total wavefront aberrations

Science.gov (United States)

Mrochen, Michael; Jankov, Mirko; Bueeler, Michael; Seiler, Theo

2002-06-01

Purpose: Corneal topography data expressed as corneal aberrations are frequently used to report corneal laser surgery results. However, the optical image quality at the retina depends on all optical elements of the eye such as the human lens. Thus, the aim of this study was to investigate the correlations between the corneal and total wavefront aberrations and to discuss the importance of corneal aberrations for representing corneal laser surgery results. Methods: Thirty three eyes of 22 myopic subjects were measured with a corneal topography system and a Tschernig-type wavefront analyzer after the pupils were dilated to at least 6 mm in diameter. All measurements were centered with respect to the line of sight. Corneal and total wavefront aberrations were calculated up to the 6th Zernike order in the same reference plane. Results: Statistically significant correlations (p the corneal and total wavefront aberrations were found for the astigmatism (C3,C5) and all 3rd Zernike order coefficients such as coma (C7,C8). No statistically significant correlations were found for all 4th to 6th order Zernike coefficients except for the 5th order horizontal coma C18 (p equals 0.003). On average, all Zernike coefficients for the corneal aberrations were found to be larger compared to Zernike coefficients for the total wavefront aberrations. Conclusions: Corneal aberrations are only of limited use for representing the optical quality of the human eye after corneal laser surgery. This is due to the lack of correlation between corneal and total wavefront aberrations in most of the higher order aberrations. Besides this, the data present in this study yield towards an aberration balancing between corneal aberrations and the optical elements within the eye that reduces the aberration from the cornea by a certain degree. Consequently, ideal customized ablations have to take both, corneal and total wavefront aberrations, into consideration.

Ibrutinib for previously untreated and relapsed or refractory chronic lymphocytic leukaemia with TP53 aberrations

DEFF Research Database (Denmark)

Farooqui, Mohammed Z H; Valdez, Janet; Martyr, Sabrina

2015-01-01

BACKGROUND: Patients with chronic lymphocytic leukaemia (CLL) with TP53 aberrations respond poorly to first-line chemoimmunotherapy, resulting in early relapse and short survival. We investigated the safety and activity of ibrutinib in previously untreated and relapsed or refractory CLL with TP53...... aberrations. METHODS: In this investigator-initiated, single-arm phase 2 study, we enrolled eligible adult patients with active CLL with TP53 aberrations at the National Institutes of Health Clinical Center (Bethesda, MD, USA). Patients received 28-day cycles of ibrutinib 420 mg orally once daily until...... in one (2%) patient. INTERPRETATION: The activity and safety profile of single-agent ibrutinib in CLL with TP53 aberrations is encouraging and supports its consideration as a novel treatment option for patients with this high-risk disease in both first-line and second-line settings. FUNDING: Intramural...

Non-linear character of dose dependences of chromosome aberration frequency in radiation-damaged root

International Nuclear Information System (INIS)

Kravets, E.A.; Berezhnaya, V.V.; Sakada, V.I.; Rashidov, N.M.; Grodzinskij, D.M.; Kravets, E.A.; Berezhnaya, V.V.; Sakada, V.I.; Rashidov, N.M.; Grodzinskij, D.M.

2012-01-01

The dose dependences of the aberrant anaphases in the root meristem in 48 hours after the irradiation have non-linear character and a plateau in the region about 6-8 Gy. The plateau indicates the activation of recovery processes. In the plateau range, the level of damages for this genotype is 33% for aberrant anaphases (FAA), 2.3 aberrations per aberrant anaphase (A/AC), and 0.74 aberrations for the total number of anaphases. At 10 Gy, the dose curve forms the exponential region caused by the involvement of the large number of new cells with unrepaired damages in the mutation process. The increase of A/AC to 1.1 indicate the ''criticality'' of the meristem radiation damage.

Spatiotemporal Data Organization and Application Research

Science.gov (United States)

Tan, C.; Yan, S.

2017-09-01

Organization and management of spatiotemporal data is a key support technology for intelligence in all fields of the smart city. The construction of a smart city cannot be realized without spatiotemporal data. Oriented to support intelligent applications this paper proposes an organizational model for spatiotemporal data, and details the construction of a spatiotemporal big data calculation, analysis, and service framework for highly efficient management and intelligent application of spatiotemporal data for the entire data life cycle.

Interaction with Shc prevents aberrant Erk activation in the absence of extracellular stimuli

KAUST Repository

Suen, KinMan

2013-05-01

Control mechanisms that prevent aberrant signaling are necessary to maintain cellular homeostasis. We describe a new mechanism by which the adaptor protein Shc directly binds the MAP kinase Erk, thus preventing its activation in the absence of extracellular stimuli. The Shc-Erk complex restricts Erk nuclear translocation, restraining Erk-dependent transcription of genes, including those responsible for oncogenic growth. The complex forms through unique binding sites on both the Shc PTB domain and the N-terminal lobe of Erk. Upon receptor tyrosine kinase stimulation, a conformational change within Shc - induced through interaction with the phosphorylated receptor - releases Erk, allowing it to fulfill its role in signaling. Thus, in addition to its established role in promoting MAP kinase signaling in stimulated cells, Shc negatively regulates Erk activation in the absence of growth factors and thus could be considered a tumor suppressor in human cells. © 2013 Nature America, Inc. All rights reserved.

Interaction with Shc prevents aberrant Erk activation in the absence of extracellular stimuli

KAUST Repository

Suen, KinMan; Lin, Chichuan; George, Roger R.; Melo, Fernando A.; Biggs, Eleanor R.; Ahmed, Zamal; Drake, Melanie N.; Arur, Swathi; Arold, Stefan T.; Ladbury, John E S D

2013-01-01

Control mechanisms that prevent aberrant signaling are necessary to maintain cellular homeostasis. We describe a new mechanism by which the adaptor protein Shc directly binds the MAP kinase Erk, thus preventing its activation in the absence of extracellular stimuli. The Shc-Erk complex restricts Erk nuclear translocation, restraining Erk-dependent transcription of genes, including those responsible for oncogenic growth. The complex forms through unique binding sites on both the Shc PTB domain and the N-terminal lobe of Erk. Upon receptor tyrosine kinase stimulation, a conformational change within Shc - induced through interaction with the phosphorylated receptor - releases Erk, allowing it to fulfill its role in signaling. Thus, in addition to its established role in promoting MAP kinase signaling in stimulated cells, Shc negatively regulates Erk activation in the absence of growth factors and thus could be considered a tumor suppressor in human cells. © 2013 Nature America, Inc. All rights reserved.

Spatiotemporal dynamics of large-scale brain activity

Science.gov (United States)

Neuman, Jeremy

Understanding the dynamics of large-scale brain activity is a tough challenge. One reason for this is the presence of an incredible amount of complexity arising from having roughly 100 billion neurons connected via 100 trillion synapses. Because of the extremely high number of degrees of freedom in the nervous system, the question of how the brain manages to properly function and remain stable, yet also be adaptable, must be posed. Neuroscientists have identified many ways the nervous system makes this possible, of which synaptic plasticity is possibly the most notable one. On the other hand, it is vital to understand how the nervous system also loses stability, resulting in neuropathological diseases such as epilepsy, a disease which affects 1% of the population. In the following work, we seek to answer some of these questions from two different perspectives. The first uses mean-field theory applied to neuronal populations, where the variables of interest are the percentages of active excitatory and inhibitory neurons in a network, to consider how the nervous system responds to external stimuli, self-organizes and generates epileptiform activity. The second method uses statistical field theory, in the framework of single neurons on a lattice, to study the concept of criticality, an idea borrowed from physics which posits that in some regime the brain operates in a collectively stable or marginally stable manner. This will be examined in two different neuronal networks with self-organized criticality serving as the overarching theme for the union of both perspectives. One of the biggest problems in neuroscience is the question of to what extent certain details are significant to the functioning of the brain. These details give rise to various spatiotemporal properties that at the smallest of scales explain the interaction of single neurons and synapses and at the largest of scales describe, for example, behaviors and sensations. In what follows, we will shed some

Correcting the Chromatic Aberration in Barrel Distortion of Endoscopic Images

Directory of Open Access Journals (Sweden)

Y. M. Harry Ng

2003-04-01

Full Text Available Modern endoscopes offer physicians a wide-angle field of view (FOV for minimally invasive therapies. However, the high level of barrel distortion may prevent accurate perception of image. Fortunately, this kind of distortion may be corrected by digital image processing. In this paper we investigate the chromatic aberrations in the barrel distortion of endoscopic images. In the past, chromatic aberration in endoscopes is corrected by achromatic lenses or active lens control. In contrast, we take a computational approach by modifying the concept of image warping and the existing barrel distortion correction algorithm to tackle the chromatic aberration problem. In addition, an error function for the determination of the level of centroid coincidence is proposed. Simulation and experimental results confirm the effectiveness of our method.

Iteration of ultrasound aberration correction methods

Science.gov (United States)

Maasoey, Svein-Erik; Angelsen, Bjoern; Varslot, Trond

2004-05-01

Aberration in ultrasound medical imaging is usually modeled by time-delay and amplitude variations concentrated on the transmitting/receiving array. This filter process is here denoted a TDA filter. The TDA filter is an approximation to the physical aberration process, which occurs over an extended part of the human body wall. Estimation of the TDA filter, and performing correction on transmit and receive, has proven difficult. It has yet to be shown that this method works adequately for severe aberration. Estimation of the TDA filter can be iterated by retransmitting a corrected signal and re-estimate until a convergence criterion is fulfilled (adaptive imaging). Two methods for estimating time-delay and amplitude variations in receive signals from random scatterers have been developed. One method correlates each element signal with a reference signal. The other method use eigenvalue decomposition of the receive cross-spectrum matrix, based upon a receive energy-maximizing criterion. Simulations of iterating aberration correction with a TDA filter have been investigated to study its convergence properties. A weak and strong human-body wall model generated aberration. Both emulated the human abdominal wall. Results after iteration improve aberration correction substantially, and both estimation methods converge, even for the case of strong aberration.

Visual representation of spatiotemporal structure

Science.gov (United States)

Schill, Kerstin; Zetzsche, Christoph; Brauer, Wilfried; Eisenkolb, A.; Musto, A.

1998-07-01

The processing and representation of motion information is addressed from an integrated perspective comprising low- level signal processing properties as well as higher-level cognitive aspects. For the low-level processing of motion information we argue that a fundamental requirement is the existence of a spatio-temporal memory. Its key feature, the provision of an orthogonal relation between external time and its internal representation, is achieved by a mapping of temporal structure into a locally distributed activity distribution accessible in parallel by higher-level processing stages. This leads to a reinterpretation of the classical concept of `iconic memory' and resolves inconsistencies on ultra-short-time processing and visual masking. The spatial-temporal memory is further investigated by experiments on the perception of spatio-temporal patterns. Results on the direction discrimination of motion paths provide evidence that information about direction and location are not processed and represented independent of each other. This suggests a unified representation on an early level, in the sense that motion information is internally available in form of a spatio-temporal compound. For the higher-level representation we have developed a formal framework for the qualitative description of courses of motion that may occur with moving objects.

[Monochromatic aberration in accommodation. Dynamic wavefront analysis].

Science.gov (United States)

Fritzsch, M; Dawczynski, J; Jurkutat, S; Vollandt, R; Strobel, J

2011-06-01

Monochromatic aberrations may influence the visual acuity of the eye. They are not stable and can be affected by different factors. The subject of the following paper is the dynamic investigation of the changes in wavefront aberration with accommodation. Dynamic measurement of higher and lower order aberrations was performed with a WASCA Wavefront Analyzer (Carl-Zeiss-Meditec) and a specially constructed target device for aligning objects in far and near distances on 25 subjects aged from 15 to 27 years old. Wavefront aberrations showed some significant changes in accommodation. In addition to the characteristic sphere reaction accompanying miosis and changes in horizontal prism (Z(1) (1)) in the sense of a convergence movement of the eyeball also occurred. Furthermore defocus rose (Z(2) (0)) and astigmatism (Z(2) (-2)) changed. In higher-order aberrations a decrease in coma-like Zernike polynomials (Z(3) (-1), Z(3) (1)) was found. The most obvious change appeared in spherical aberration (Z(4) (0)) which increased and changed from positive to negative. In addition the secondary astigmatism (Z(4) (-2)) and quadrafoil (Z(4) (4)) rise also increased. The total root mean square (RMS), as well as the higher-order aberrations (RMS-HO) significantly increased in accommodation which is associated with a theoretical reduction of visual acuity. An analysis of the influence of pupil size on aberrations showed significant increases in defocus, spherical aberration, quadrafoil, RMS and RMS HO by increasing pupil diameter. By accommodation-associated miosis, the growing aberrations are partially compensated by focusing on near objects. Temporal analysis of the accommodation process with dynamic wavefront analysis revealed significant delays in pupil response and changing of prism in relation to the sphere reaction. In accommodation to near objects a discrete time ahead of third order aberrations in relation to the sphere response was found. Using dynamic wavefront measurement

DNA Repair Defects and Chromosomal Aberrations

Science.gov (United States)

Hada, Megumi; George, K. A.; Huff, J. L.; Pluth, J. M.; Cucinotta, F. A.

2009-01-01

Yields of chromosome aberrations were assessed in cells deficient in DNA doublestrand break (DSB) repair, after exposure to acute or to low-dose-rate (0.018 Gy/hr) gamma rays or acute high LET iron nuclei. We studied several cell lines including fibroblasts deficient in ATM (ataxia telangiectasia mutated; product of the gene that is mutated in ataxia telangiectasia patients) or NBS (nibrin; product of the gene mutated in the Nijmegen breakage syndrome), and gliomablastoma cells that are proficient or lacking in DNA-dependent protein kinase (DNA-PK) activity. Chromosomes were analyzed using the fluorescence in situ hybridization (FISH) chromosome painting method in cells at the first division post irradiation, and chromosome aberrations were identified as either simple exchanges (translocations and dicentrics) or complex exchanges (involving >2 breaks in 2 or more chromosomes). Gamma irradiation induced greater yields of both simple and complex exchanges in the DSB repair-defective cells than in the normal cells. The quadratic dose-response terms for both simple and complex chromosome exchanges were significantly higher for the ATM- and NBS-deficient lines than for normal fibroblasts. However, in the NBS cells the linear dose-response term was significantly higher only for simple exchanges. The large increases in the quadratic dose-response terms in these repair-defective cell lines points the importance of the functions of ATM and NBS in chromatin modifications to facilitate correct DSB repair and minimize the formation of aberrations. The differences found between ATM- and NBS-deficient cells at low doses suggest that important questions should with regard to applying observations of radiation sensitivity at high dose to low-dose exposures. For aberrations induced by iron nuclei, regression models preferred purely linear dose responses for simple exchanges and quadratic dose responses for complex exchanges. Relative biological effectiveness (RBE) factors of all of

A novel spatiotemporal muscle activity imaging approach based on the Extended Kalman Filter.

Science.gov (United States)

Wang, Jing; Zhang, Yingchun; Zhu, Xiangjun; Zhou, Ping; Liu, Chenguang; Rymer, William Z

2012-01-01

A novel spatiotemporal muscle activity imaging (sMAI) approach has been developed using the Extended Kalman Filter (EKF) to reconstruct internal muscle activities from non-invasive multi-channel surface electromyogram (sEMG) recordings. A distributed bioelectric dipole source model is employed to describe the internal muscle activity space, and a linear relationship between the muscle activity space and the sEMG measurement space is then established. The EKF is employed to recursively solve the ill-posed inverse problem in the sMAI approach, in which the weighted minimum norm (WMN) method is utilized to calculate the initial state and a new nonlinear method is developed based on the propagating features of muscle activities to predict the recursive state. A series of computer simulations was conducted to test the performance of the proposed sMAI approach. Results show that the localization error rapidly decreases over 35% and the overlap ratio rapidly increases over 45% compared to the results achieved using the WMN method only. The present promising results demonstrate the feasibility of utilizing the proposed EKF-based sMAI approach to accurately reconstruct internal muscle activities from non-invasive sEMG recordings.

In vivo imaging of hierarchical spatiotemporal activation of caspase-8 during apoptosis.

Directory of Open Access Journals (Sweden)

Katsuya Kominami

Full Text Available BACKGROUND: Activation of caspases is crucial for the execution of apoptosis. Although the caspase cascade associated with activation of the initiator caspase-8 (CASP8 has been investigated in molecular and biochemical detail, the dynamics of CASP8 activation are not fully understood. METHODOLOGY/PRINCIPAL FINDINGS: We have established a biosensor based on fluorescence resonance energy transfer (FRET for visualizing apoptotic signals associated with CASP8 activation at the single-cell level. Our dual FRET (dual-FRET system, comprising a triple fusion fluorescent protein, enabled us to simultaneously monitor the activation of CASP8 and its downstream effector, caspase-3 (CASP3 in single live cells. With the dual-FRET-based biosensor, we detected distinct activation patterns of CASP8 and CASP3 in response to various apoptotic stimuli in mammalian cells, resulting in the positive feedback amplification of CASP8 activation. We reproduced these observations by in vitro reconstitution of the cascade, with a recombinant protein mixture that included procaspases. Furthermore, using a plasma membrane-bound FRET-based biosensor, we captured the spatiotemporal dynamics of CASP8 activation by the diffusion process, suggesting the focal activation of CASP8 is sufficient to propagate apoptotic signals through death receptors. CONCLUSIONS: Our new FRET-based system visualized the activation process of both initiator and effector caspases in a single apoptotic cell and also elucidated the necessity of an amplification loop for full activation of CASP8.

Spatio-temporal patterns in simple models of marine systems

Science.gov (United States)

Feudel, U.; Baurmann, M.; Gross, T.

2009-04-01

Spatio-temporal patterns in marine systems are a result of the interaction of population dynamics with physical transport processes. These physical transport processes can be either diffusion processes in marine sediments or in the water column. We study the dynamics of one population of bacteria and its nutrient in in a simplified model of a marine sediments, taking into account that the considered bacteria possess an active as well as an inactive state, where activation is processed by signal molecules. Furthermore the nutrients are transported actively by bioirrigation and passively by diffusion. It is shown that under certain conditions Turing patterns can occur which yield heterogeneous spatial patterns of the species. The influence of bioirrigation on Turing patterns leads to the emergence of ''hot spots``, i.e. localized regions of enhanced bacterial activity. All obtained patterns fit quite well to observed patterns in laboratory experiments. Spatio-temporal patterns appear in a predator-prey model, used to describe plankton dynamics. These patterns appear due to the simultaneous emergence of Turing patterns and oscillations in the species abundance in the neighborhood of a Turing-Hopf bifurcation. We observe a large variety of different patterns where i) stationary heterogeneous patterns (e.g. hot and cold spots) compete with spatio-temporal patterns ii) slowly moving patterns are embedded in an oscillatory background iii) moving fronts and spiral waves appear.

Spatiotemporal Modeling of Community Risk

Science.gov (United States)

2016-03-01

Ertugay, and Sebnem Duzgun, “Exploratory and Inferential Methods for Spatio-Temporal Analysis of Residential Fire Clustering in Urban Areas,” Fire ...response in communities.”26 In “Exploratory and Inferential Methods for Spatio-temporal Analysis of Residential Fire Clustering in Urban Areas,” Ceyhan...of fire resources spread across the community. Spatiotemporal modeling shows that actualized risk is dynamic and relatively patterned. Though

The prediction of spherical aberration with schematic eyes.

Science.gov (United States)

Liou, H L; Brennan, N A

1996-07-01

Many model eyes have been proposed; they differ in optical characteristics and therefore have different aberrations and image quality. In predicting the visual performance of the eye, we are most concerned with the central foveal vision. Spherical aberration is the only on-axis monochromatic aberration and can be used as a criterion to assess the degree of resemblance of eye models to the human eye. We reviewed and compiled experimental values of the spherical aberration of the eye, calculated the spherical aberration of several different categories of model eyes and compared the calculated results to the experimental data. Results show an over-estimation of spherical aberration by all models, the finite schematic eyes predicting values of spherical aberration closest to the experimental data. Current model eyes do not predict the average experimental values of the spherical aberration of the eye. A new model eye satisfying this assessment criterion is required for investigations of the visual performance of the eye.

Imaging characteristics of Zernike and annular polynomial aberrations.

Science.gov (United States)

Mahajan, Virendra N; Díaz, José Antonio

2013-04-01

The general equations for the point-spread function (PSF) and optical transfer function (OTF) are given for any pupil shape, and they are applied to optical imaging systems with circular and annular pupils. The symmetry properties of the PSF, the real and imaginary parts of the OTF, and the modulation transfer function (MTF) of a system with a circular pupil aberrated by a Zernike circle polynomial aberration are derived. The interferograms and PSFs are illustrated for some typical polynomial aberrations with a sigma value of one wave, and 3D PSFs and MTFs are shown for 0.1 wave. The Strehl ratio is also calculated for polynomial aberrations with a sigma value of 0.1 wave, and shown to be well estimated from the sigma value. The numerical results are compared with the corresponding results in the literature. Because of the same angular dependence of the corresponding annular and circle polynomial aberrations, the symmetry properties of systems with annular pupils aberrated by an annular polynomial aberration are the same as those for a circular pupil aberrated by a corresponding circle polynomial aberration. They are also illustrated with numerical examples.

Geometric characteristics of aberrations of plane-symmetric optical systems

International Nuclear Information System (INIS)

Lu Lijun; Deng Zhiyong

2009-01-01

The geometric characteristics of aberrations of plane-symmetric optical systems are studied in detail with a wave-aberration theory. It is dealt with as an extension of the Seidel aberrations to realize a consistent aberration theory from axially symmetric to plane-symmetric systems. The aberration distribution is analyzed with the spot diagram of a ray and an aberration curve. Moreover, the root-mean-square value and the centroid of aberration distribution are discussed. The numerical results are obtained with the focusing optics of a toroidal mirror at grazing incidence.

Nodal aberration theory applied to freeform surfaces

Science.gov (United States)

Fuerschbach, Kyle; Rolland, Jannick P.; Thompson, Kevin P.

2014-12-01

When new three-dimensional packages are developed for imaging optical systems, the rotational symmetry of the optical system is often broken, changing its imaging behavior and making the optical performance worse. A method to restore the performance is to use freeform optical surfaces that compensate directly the aberrations introduced from tilting and decentering the optical surfaces. In order to effectively optimize the shape of a freeform surface to restore optical functionality, it is helpful to understand the aberration effect the surface may induce. Using nodal aberration theory the aberration fields induced by a freeform surface in an optical system are explored. These theoretical predications are experimentally validated with the design and implementation of an aberration generating telescope.

Spatiotemporal representation of cardiac vectorcardiogram (VCG signals

Directory of Open Access Journals (Sweden)

Yang Hui

2012-03-01

Full Text Available Abstract Background Vectorcardiogram (VCG signals monitor both spatial and temporal cardiac electrical activities along three orthogonal planes of the body. However, the absence of spatiotemporal resolution in conventional VCG representations is a major impediment for medical interpretation and clinical usage of VCG. This is especially so because time-domain features of 12-lead ECG, instead of both spatial and temporal characteristics of VCG, are widely used for the automatic assessment of cardiac pathological patterns. Materials and methods We present a novel representation approach that captures critical spatiotemporal heart dynamics by displaying the real time motion of VCG cardiac vectors in a 3D space. Such a dynamic display can also be realized with only one lead ECG signal (e.g., ambulatory ECG through an alternative lag-reconstructed ECG representation from nonlinear dynamics principles. Furthermore, the trajectories are color coded with additional dynamical properties of space-time VCG signals, e.g., the curvature, speed, octant and phase angles to enhance the information visibility. Results In this investigation, spatiotemporal VCG signal representation is used to characterize various spatiotemporal pathological patterns for healthy control (HC, myocardial infarction (MI, atrial fibrillation (AF and bundle branch block (BBB. The proposed color coding scheme revealed that the spatial locations of the peak of T waves are in the Octant 6 for the majority (i.e., 74 out of 80 of healthy recordings in the PhysioNet PTB database. In contrast, the peak of T waves from 31.79% (117/368 of MI subjects are found to remain in Octant 6 and the rest (68.21% spread over all other octants. The spatiotemporal VCG signal representation is shown to capture the same important heart characteristics as the 12-lead ECG plots and more. Conclusions Spatiotemporal VCG signal representation is shown to facilitate the characterization of space-time cardiac

Elimination of spiral waves and spatiotemporal chaos by the pulse with a specific spatiotemporal configuration

International Nuclear Information System (INIS)

Yuan Guoyong; Yang Shiping; Wang Guangrui; Chen Shigang

2008-01-01

Spiral waves and spatiotemporal chaos are sometimes harmful and should be controlled. In this paper spiral waves and spatiotemporal chaos are successfully eliminated by the pulse with a very specific spatiotemporal configuration. The excited position D of spiral waves or spatiotemporal chaos is first recorded at an arbitrary time (t 0 ). When the system at the domain D enters a recovering state, the external pulse is injected into the domain. If the intensity and the working time of the pulse are appropriate, spiral waves and spatiotemporal chaos can finally be eliminated because counter-directional waves can be generated by the pulse. There are two advantages in the method. One is that the tip can be quickly eliminated together with the body of spiral wave, and the other is that the injected pulse may be weak and the duration can be very short so that the original system is nearly not affected, which is important for practical applications

Tensor-based spatiotemporal saliency detection

Science.gov (United States)

Dou, Hao; Li, Bin; Deng, Qianqian; Zhang, LiRui; Pan, Zhihong; Tian, Jinwen

2018-03-01

This paper proposes an effective tensor-based spatiotemporal saliency computation model for saliency detection in videos. First, we construct the tensor representation of video frames. Then, the spatiotemporal saliency can be directly computed by the tensor distance between different tensors, which can preserve the complete temporal and spatial structure information of object in the spatiotemporal domain. Experimental results demonstrate that our method can achieve encouraging performance in comparison with the state-of-the-art methods.

Retrospective chromosome aberration analysis of former uranium miners

International Nuclear Information System (INIS)

Meszaros, G.; Bognar, G.; Koeteles, G. J.

2003-01-01

In this paper we present our data collected in the period of 1981-1985 on 165 persons exposed by different radon concentrations expressed in working level month (WLM) units from 100 up to 600. Following the decommissioning of the uranium mine in Hungary in 1997 cytogenetic status of 131 persons were within a follow-up-study of their health conditions initiated by the Hungarian Academy of Science. The persons have terminated their underground activities 5 to 20 years before testing. The comparison of the two datasets suggest a long-term persistence of cytogenetic alterations above the population average values in large percentages of persons investigated. The frequency of chromosome aberrations of uranium miners was found increased in function of their exposure to radon. The comparison of the miner's categories 20 years ago and in the recent years demonstrated the long-term existence of aberrations for many years after completion of underground mining activities. (authors)

Aberration characteristics of immersion lenses for LVSEM

International Nuclear Information System (INIS)

Khursheed, Anjam

2002-01-01

This paper investigates the on-axis aberration characteristics of various immersion objective lenses for low voltage scanning electron microscopy (LVSEM). A simple aperture lens model is used to generate smooth axial field distributions. The simulation results show that mixed field electric-magnetic immersion lenses are predicted to have between 1.5 and 2 times smaller aberration limited probe diameters than their pure-field counterparts. At a landing energy of 1 keV, mixed field immersion lenses operating at the vacuum electrical field breakdown limit are predicted to have on-axis aberration coefficients between 50 and 60 μm, yielding an ultimate image resolution of below 1 nm. These aberrations lie in the same range as those for LVSEM systems that employ aberration correctors

Chromatin structure and ionizing-radiation-induced chromosome aberrations

International Nuclear Information System (INIS)

Muehlmann-Diaz, M.C.

1993-01-01

The possible influence of chromatic structure or activity on chromosomal radiosensitivity was studied. A cell line was isolated which contained some 10 5 copies of an amplified plasmid in a single large mosquito artificial chromosome (MAC). This chromosome was hypersensitive to DNase I. Its radiosensitivity was some three fold greater than normal mosquito chromosomes in the same cell. In cultured human cells irradiated during G 0 , the initial breakage frequency in chromosome 4, 19 and the euchromatic and heterochromatic portions of the Y chromosome were measured over a wide range of doses by inducing Premature Chromosome Condensation (PCC) immediately after irradiation with Cs-137 gamma rays. No evidence was seen that Y heterochromatin or large fragments of it remained unbroken. The only significant deviation from the expected initial breakage frequency per Gy per unit length of chromosome was that observed for the euchromatic portion of the Y chromosome, with breakage nearly twice that expected. The development of aberrations involving X and Y chromosomes at the first mitosis after irradation was also studied. Normal female cells sustained about twice the frequency of aberrations involving X chromosomes for a dose of 7.3 Gy than the corresponding male cells. Fibroblasts from individuals with supernumerary X chromosomes did not show any further increase in X aberrations for this dos. The frequency of aberrations involving the heterochromatic portion of the long arm of the Y chromosome was about what would be expected for a similar length of autosome, but the euchromatic portion of the Y was about 3 times more radiosensitive per unit length. 5-Azacytidine treatment of cultured human female fibroblasts or fibroblasts from a 49,XXXXY individual, reduced the methylation of cytosine residues in DNA, and resulted in an increased chromosomal radiosensitivity in general, but it did not increase the frequency of aberrations involving the X chromosomes

Freeform aberrations in phase space: an example.

Science.gov (United States)

Babington, James

2017-06-01

We consider how optical propagation and aberrations of freeform systems can be formulated in phase space. As an example system, a freeform prism is analyzed and discussed. Symmetry considerations and their group theory descriptions are given some importance. Numerical aberrations are also highlighted and put into the context of the underlying aberration theory.

Spherical aberrations of human astigmatic corneas.

Science.gov (United States)

Zhao, Huawei; Dai, Guang-Ming; Chen, Li; Weeber, Henk A; Piers, Patricia A

2011-11-01

To evaluate whether the average spherical aberration of human astigmatic corneas is statistically equivalent to human nonastigmatic corneas. Spherical aberrations of 445 astigmatic corneas prior to laser vision correction were retrospectively investigated to determine Zernike coefficients for central corneal areas 6 mm in diameter using CTView (Sarver and Associates). Data were divided into groups according to cylinder power (0.01 to 0.25 diopters [D], 0.26 to 0.75 D, 0.76 to 1.06 D, 1.07 to 1.53 D, 1.54 to 2.00 D, and >2.00 D) and according to age by decade. Spherical aberrations were correlated with age and astigmatic power among groups and the entire population. Statistical analyses were conducted, and P.05 for all tested groups). Mean spherical aberration of astigmatic corneas was not correlated significantly with cylinder power or age (P>.05). Spherical aberrations are similar to those of nonastigmatic corneas, permitting the use of these additional data in the design of aspheric toric intra-ocular lenses. Copyright 2011, SLACK Incorporated.

Spatiotemporal Psychopathology II: How does a psychopathology of the brain's resting state look like? Spatiotemporal approach and the history of psychopathology.

Science.gov (United States)

Northoff, Georg

2016-01-15

Psychopathology as the investigation and classification of experience, behavior and symptoms in psychiatric patients is an old discipline that ranges back to the end of the 19th century. Since then different approaches to psychopathology have been suggested. Recent investigations showing abnormalities in the brain on different levels raise the question how the gap between brain and psyche, between neural abnormalities and alteration in experience and behavior can be bridged. Historical approaches like descriptive (Jaspers) and structural (Minkoswki) psychopathology as well as the more current phenomenological psychopathology (Paarnas, Fuchs, Sass, Stanghellini) remain on the side of the psyche giving detailed description of the phenomenal level of experience while leaving open the link to the brain. In contrast, the recently introduced Research Domain Classification (RDoC) aims at explicitly linking brain and psyche by starting from so-called 'neuro-behavioral constructs'. How does Spatiotemporal Psychopathology, as demonstrated in the first paper on depression, stand in relation to these approaches? In a nutshell, Spatiotemporal Psychopathology aims to bridge the gap between brain and psyche. Specifically, as demonstrated in depression in the first paper, the focus is on the spatiotemporal features of the brain's intrinsic activity and how they are transformed into corresponding spatiotemporal features in experience on the phenomenal level and behavioral changes, which can well account for the symptoms in these patients. This second paper focuses on some of the theoretical background assumptions in Spatiotemporal Psychopathology by directly comparing it to descriptive, structural, and phenomenological psychopathology as well as to RDoC. Copyright © 2015 Elsevier B.V. All rights reserved.

Whole eye wavefront aberrations in Mexican male subjects.

Science.gov (United States)

Cantú, Roberto; Rosales, Marco A; Tepichín, Eduardo; Curioca, Andrée; Montes, Victor; Bonilla, Julio

2004-01-01

To analyze the characteristics, incidence, and appearance of wavefront aberrations in undilated, normal, unoperated eyes. Eighty-eight eyes of 44 healthy male Mexican subjects (mean age 25.32 years, range 18 to 36 yr) were divided into three groups based on uncorrected visual acuity of greater than or equal to 20/20, 20/30, or 20/40. UCVA measurements were obtained using an Acuity Max computer screen chart. Wavefront aberrations were measured with the Nidek OPD-Scan ARK 10000, Ver. 1.11b. All measurements were carried out at the same center by the same technician during a single session, following manufacturer instructions. Background illumination was 3 Lux. Wavefront aberration measurements for each group were statistically analyzed using StatView; an average eye was characterized and the resulting aberrations were simulated using MATLAB. We obtained wavefront aberration maps for the 20/20 undilated normal unoperated eyes for total, low, and high order aberration coefficients. Wavefront maps for right eyes were practically the same as those for left eyes. Higher aberrations did not contribute substantially to total wavefront analysis. Average aberrations of this "normal eye" will be used as criteria to decide the necessity of wavefront-guided ablation in our facilities. We will focus on the nearly zero average of high order aberrations in this normal whole eye as a reference to be matched.

Aberrant DNA Methylation in Chronic Myeloid Leukemia: Cell Fate Control, Prognosis, and Therapeutic Response.

Science.gov (United States)

Behzad, Masumeh Maleki; Shahrabi, Saeid; Jaseb, Kaveh; Bertacchini, Jessika; Ketabchi, Neda; Saki, Najmaldin

2018-01-31

Chronic myeloid leukemia (CML) is a hematopoietic stem cell malignancy characterized by the expression of the BCR-ABL1 fusion gene with different chimeric transcripts. Despite the crucial impact of constitutively active tyrosine kinase in CML pathogenesis, aberrant DNA methylation of certain genes plays an important role in disease progression and the development of drug resistance. This article reviews recent findings relevant to the effect of DNA methylation pattern of regulatory genes on various cellular activities such as cell proliferation and survival, as well as cell-signaling molecules in CML. These data might contribute to defining the role of aberrant DNA methylation in disease initiation and progression. However, further studies are needed on the validation of specific aberrant methylation markers regarding the prognosis and prediction of response among the CML patients.

Transient spatiotemporal chaos in the Morris-Lecar neuronal ring network

Energy Technology Data Exchange (ETDEWEB)

Keplinger, Keegan, E-mail: keegankeplinger@gmail.com; Wackerbauer, Renate, E-mail: rawackerbauer@alaska.edu [Department of Physics, University of Alaska, Fairbanks, Alaska 99775-5920 (United States)

2014-03-15

Transient behavior is thought to play an integral role in brain functionality. Numerical simulations of the firing activity of diffusively coupled, excitable Morris-Lecar neurons reveal transient spatiotemporal chaos in the parameter regime below the saddle-node on invariant circle bifurcation point. The neighborhood of the chaotic saddle is reached through perturbations of the rest state, in which few initially active neurons at an effective spatial distance can initiate spatiotemporal chaos. The system escapes from the neighborhood of the chaotic saddle to either the rest state or to a state of pulse propagation. The lifetime of the chaotic transients is manipulated in a statistical sense through a singular application of a synchronous perturbation to a group of neurons.

Transient spatiotemporal chaos in the Morris-Lecar neuronal ring network.

Science.gov (United States)

Keplinger, Keegan; Wackerbauer, Renate

2014-03-01

Transient behavior is thought to play an integral role in brain functionality. Numerical simulations of the firing activity of diffusively coupled, excitable Morris-Lecar neurons reveal transient spatiotemporal chaos in the parameter regime below the saddle-node on invariant circle bifurcation point. The neighborhood of the chaotic saddle is reached through perturbations of the rest state, in which few initially active neurons at an effective spatial distance can initiate spatiotemporal chaos. The system escapes from the neighborhood of the chaotic saddle to either the rest state or to a state of pulse propagation. The lifetime of the chaotic transients is manipulated in a statistical sense through a singular application of a synchronous perturbation to a group of neurons.

Measuring and correcting aberrations of a cathode objective lens

International Nuclear Information System (INIS)

Tromp, R.M.

2011-01-01

In this paper I discuss several theoretical and practical aspects related to measuring and correcting the chromatic and spherical aberrations of a cathode objective lens as used in Low Energy Electron Microscopy (LEEM) and Photo Electron Emission Microscopy (PEEM) experiments. Special attention is paid to the various components of the cathode objective lens as they contribute to chromatic and spherical aberrations, and affect practical methods for aberration correction. This analysis has enabled us to correct a LEEM instrument for the spherical and chromatic aberrations of the objective lens. -- Research highlights: → Presents a comprehensive theory of the relation between chromatic aberration and lens current in a cathode objective lens. → Presents practical methods for measuring both spherical and chromatic aberrations of a cathode objective lens. → Presents measurements of these aberrations in good agreement with theory. → Presents practical methods for measuring and correcting these aberrations with an electron mirror.

How about a Bayesian M/EEG imaging method correcting for incomplete spatio-temporal priors

DEFF Research Database (Denmark)

Stahlhut, Carsten; Attias, Hagai T.; Sekihara, Kensuke

2013-01-01

previous spatio-temporal inverse M/EEG models, the proposed model benefits of consisting of two source terms, namely, a spatio-temporal pattern term limiting the source configuration to a spatio-temporal subspace and a source correcting term to pick up source activity not covered by the spatio......-temporal prior belief. We have tested the model on both artificial data and real EEG data in order to demonstrate the efficacy of the model. The model was tested at different SNRs (-10.0,-5.2, -3.0, -1.0, 0, 0.8, 3.0 dB) using white noise. At all SNRs the sAquavit performs best in AUC measure, e.g. at SNR=0d...

Spatio-Temporal Analysis of Human Activities in Indoor Environments through Mobile Sensing

DEFF Research Database (Denmark)

Prentow, Thor Siiger

with the intuition and personal experience of the planners. Lack of real-time information on task execution has made it difficult to adapt to changes in the schedules, such as delays or suddenly occurring urgent tasks. The recent advances in methods and devices for mobile sensing provides opportunities...... methods for spatio-temporal analysis of human activities in indoor environments based on mobile sensing. The methods aim to improve scheduling and facility utilization by providing information on the used route networks, transportation modes, travel times, and the flow of people through buildings....... The methods are based on large-scale real-time indoor positioning through the use of existing WiFi infrastructures, which allows for easy deployment even in very large building complexes. The methods are designed for real-time operation, which enables them to detect and adjust to changes as they occur...

The significance of PTEN and AKT aberrations in pediatric T-cell acute lymphoblastic leukemia

Science.gov (United States)

Zuurbier, Linda; Petricoin, Emanuel F.; Vuerhard, Maartje J.; Calvert, Valerie; Kooi, Clarissa; Buijs-Gladdines, Jessica G.C.A.M.; Smits, Willem K.; Sonneveld, Edwin; Veerman, Anjo J.P.; Kamps, Willem A.; Horstmann, Martin; Pieters, Rob; Meijerink, Jules P.P.

2012-01-01

Background PI3K/AKT pathway mutations are found in T-cell acute lymphoblastic leukemia, but their overall impact and associations with other genetic aberrations is unknown. PTEN mutations have been proposed as secondary mutations that follow NOTCH1-activating mutations and cause cellular resistance to γ-secretase inhibitors. Design and Methods The impact of PTEN, PI3K and AKT aberrations was studied in a genetically well-characterized pediatric T-cell leukemia patient cohort (n=146) treated on DCOG or COALL protocols. Results PTEN and AKT E17K aberrations were detected in 13% and 2% of patients, respectively. Defective PTEN-splicing was identified in incidental cases. Patients without PTEN protein but lacking exon-, splice-, promoter mutations or promoter hypermethylation were present. PTEN/AKT mutations were especially abundant in TAL- or LMO-rearranged leukemia but nearly absent in TLX3-rearranged patients (P=0.03), the opposite to that observed for NOTCH1-activating mutations. Most PTEN/AKT mutant patients either lacked NOTCH1-activating mutations (P=0.006) or had weak NOTCH1-activating mutations (P=0.011), and consequently expressed low intracellular NOTCH1, cMYC and MUSASHI levels. T-cell leukemia patients without PTEN/AKT and NOTCH1-activating mutations fared well, with a cumulative incidence of relapse of only 8% versus 35% for PTEN/AKT and/or NOTCH1-activated patients (P=0.005). Conclusions PI3K/AKT pathway aberrations are present in 18% of pediatric T-cell acute lymphoblastic leukemia patients. Absence of strong NOTCH1-activating mutations in these cases may explain cellular insensitivity to γ-secretase inhibitors. PMID:22491738

Aberrant TAL1 activation is mediated by an interchromosomal interaction in human T-cell acute lymphoblastic leukemia.

Science.gov (United States)

Patel, B; Kang, Y; Cui, K; Litt, M; Riberio, M S J; Deng, C; Salz, T; Casada, S; Fu, X; Qiu, Y; Zhao, K; Huang, S

2014-02-01

Long-range chromatin interactions control metazoan gene transcription. However, the involvement of intra- and interchromosomal interactions in development and oncogenesis remains unclear. TAL1/SCL is a critical transcription factor required for the development of all hematopoietic lineages; yet, aberrant TAL1 transcription often occurs in T-cell acute lymphoblastic leukemia (T-ALL). Here, we report that oncogenic TAL1 expression is regulated by different intra- and interchromosomal loops in normal hematopoietic and leukemic cells, respectively. These intra- and interchromosomal loops alter the cell-type-specific enhancers that interact with the TAL1 promoter. We show that human SET1 (hSET1)-mediated H3K4 methylations promote a long-range chromatin loop, which brings the +51 enhancer in close proximity to TAL1 promoter 1 in erythroid cells. The CCCTC-binding factor (CTCF) facilitates this long-range enhancer/promoter interaction of the TAL1 locus in erythroid cells while blocking the same enhancer/promoter interaction of the TAL1 locus in human T-cell leukemia. In human T-ALL, a T-cell-specific transcription factor c-Maf-mediated interchromosomal interaction brings the TAL1 promoter into close proximity with a T-cell-specific regulatory element located on chromosome 16, activating aberrant TAL1 oncogene expression. Thus, our study reveals a novel molecular mechanism involving changes in three-dimensional chromatin interactions that activate the TAL1 oncogene in human T-cell leukemia.

Chromosomal aberrations in ore miners of Slovakia

International Nuclear Information System (INIS)

Beno, M.; Vladar, M.; Nikodemova, D.; Vicanova, M.; Durcik, M.

1998-01-01

A pilot study was performed in which the incidence of chromosomal aberrations in lymphocytes of miners in ore mines located in Central Slovakia was monitored and related to lifetime underground radon exposure and to lifetime smoking. The conclusions drawn from the results of the study were as follows: the counts of chromosomal aberrations in lymphocytes of miners were significantly higher than in an age matched control group of white-collar staff; the higher counts of chromosomal aberrations could be ascribed to underground exposure of miners and to smoking; a dependence of chromosomal aberration counts on the exposure to radon could not be assessed. (A.K.)

Aberration studies and computer algebra

International Nuclear Information System (INIS)

Hawkes, P.W.

1981-01-01

The labour of calculating expressions for aberration coefficients is considerably lightened if a computer algebra language is used to perform the various substitutions and expansions involved. After a brief discussion of matrix representations of aberration coefficients, a particular language, which has shown itself to be well adapted to particle optics, is described and applied to the study of high frequency cavity lenses. (orig.)

Theoretical investigation of aberrations upon ametropic human eyes

Science.gov (United States)

Tan, Bo; Chen, Ying-Ling; Lewis, J. W. L.; Baker, Kevin

2003-11-01

The human eye aberrations are important for visual acuity and ophthalmic diagnostics and surgical procedures. Reported monochromatic aberration data of the normal 20/20 human eyes are scarce. There exist even fewer reports of the relation between ametropic conditions and aberrations. We theoretically investigate the monochromatic and chromatic aberrations of human eyes for refractive errors of -10 to +10 diopters. Schematic human eye models are employed using optical design software for axial, index, and refractive types of ametropia.

Spatio-temporal analysis of brain electrical activity in epilepsy based on cellular nonlinear networks

Science.gov (United States)

Gollas, Frank; Tetzlaff, Ronald

2009-05-01

Epilepsy is the most common chronic disorder of the nervous system. Generally, epileptic seizures appear without foregoing sign or warning. The problem of detecting a possible pre-seizure state in epilepsy from EEG signals has been addressed by many authors over the past decades. Different approaches of time series analysis of brain electrical activity already are providing valuable insights into the underlying complex dynamics. But the main goal the identification of an impending epileptic seizure with a sufficient specificity and reliability, has not been achieved up to now. An algorithm for a reliable, automated prediction of epileptic seizures would enable the realization of implantable seizure warning devices, which could provide valuable information to the patient and time/event specific drug delivery or possibly a direct electrical nerve stimulation. Cellular Nonlinear Networks (CNN) are promising candidates for future seizure warning devices. CNN are characterized by local couplings of comparatively simple dynamical systems. With this property these networks are well suited to be realized as highly parallel, analog computer chips. Today available CNN hardware realizations exhibit a processing speed in the range of TeraOps combined with low power consumption. In this contribution new algorithms based on the spatio-temporal dynamics of CNN are considered in order to analyze intracranial EEG signals and thus taking into account mutual dependencies between neighboring regions of the brain. In an identification procedure Reaction-Diffusion CNN (RD-CNN) are determined for short segments of brain electrical activity, by means of a supervised parameter optimization. RD-CNN are deduced from Reaction-Diffusion Systems, which usually are applied to investigate complex phenomena like nonlinear wave propagation or pattern formation. The Local Activity Theory provides a necessary condition for emergent behavior in RD-CNN. In comparison linear spatio-temporal

Flow cytogenetics: progress toward chromosomal aberration detection

International Nuclear Information System (INIS)

Carrano, A.V.; Gray, J.W.; Van Dilla, M.A.

1977-01-01

Using clonal derivatives of the Chinese hamster M3-1 cell line, we demonstrate the potential of flow systems to karyotype homogeneous aberrations (aberrations which are identical and present in every cell) and to detect heterogeneous aberrations (aberrations which occur randomly in a population and are not identical in every cell). Flow cytometry (FCM) of ethidium bromide stained isolated chromosomes from clone 650A of the M3-1 cells distinguishes nine chromosome types from the fourteen present in the actual karyotype. X-irradiation of this parent 650A clone produced two sub-clones with an altered flow karyotype, that is, their FCM distributions were characterized by the addition of new peaks and alterations in area under existing peaks. From the relative DNA content and area for each peak, as determined by computer analysis, we predicted that each clone had undergone a reciprocal translocation involving chromosomes from two peaks. This prediction was confirmed by Giemsa-banding the metaphase cells. Heterogeneous aberrations are reflected in the flow karyotype as an increase in background, that is, an increase in area underlying the chromosome peaks. This increase is dose dependent but, as yet, the sample variability has been too large for quantitative analysis. Flow sorting of the valleys between chromosome peaks produces enriched fractions of aberrant chromosomes for visual analysis. These approaches are potentially applicable to the analysis of chromsomal aberrations induced by environmental contaminants

Aberration-corrected STEM: current performance and future directions

Energy Technology Data Exchange (ETDEWEB)

Nellist, P D [Department of Physics, University of Dublin, Trinity College, Dublin 2 (Ireland); Chisholm, M F [Condensed Matter Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6030 (United States); Lupini, A R [Condensed Matter Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6030 (United States); Borisevich, A [Condensed Matter Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6030 (United States); Jr, W H Sides [Condensed Matter Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6030 (United States); Pennycook, S J [Condensed Matter Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6030 (United States); Dellby, N [Nion Co., 1102 8th St., Kirkland, WA 98033 (United States); Keyse, R [Nion Co., 1102 8th St., Kirkland, WA 98033 (United States); Krivanek, O L [Nion Co., 1102 8th St., Kirkland, WA 98033 (United States); Murfitt, M F [Nion Co., 1102 8th St., Kirkland, WA 98033 (United States); Szilagyi, Z S [Nion Co., 1102 8th St., Kirkland, WA 98033 (United States)

2006-02-22

Through the correction of spherical aberration in the scanning transmission electron microscope (STEM), the resolving of a 78 pm atomic column spacing has been demonstrated along with information transfer to 61 pm. The achievement of this resolution required careful control of microscope instabilities, parasitic aberrations and the compensation of uncorrected, higher order aberrations. Many of these issues are improved in a next generation STEM fitted with a new design of aberration corrector, and an initial result demonstrating aberration correction to a convergence semi-angle of 40 mrad is shown. The improved spatial resolution and beam convergence allowed for by such correction has implications for the way in which experiments are performed and how STEM data should be interpreted.

Nodal aberration theory for wild-filed asymmetric optical systems

Science.gov (United States)

Chen, Yang; Cheng, Xuemin; Hao, Qun

2016-10-01

Nodal Aberration Theory (NAT) was used to calculate the zero field position in Full Field Display (FFD) for the given aberration term. Aiming at wide-filed non-rotational symmetric decentered optical systems, we have presented the nodal geography behavior of the family of third-order and fifth-order aberrations. Meanwhile, we have calculated the wavefront aberration expressions when one optical element in the system is tilted, which was not at the entrance pupil. By using a three-piece-cellphone lens example in optical design software CodeV, the nodal geography is testified under several situations; and the wavefront aberrations are calculated when the optical element is tilted. The properties of the nodal aberrations are analyzed by using Fringe Zernike coefficients, which are directly related with the wavefront aberration terms and usually obtained by real ray trace and wavefront surface fitting.

Spatio-temporal regulation of Hsp90-ligand complex leads to immune activation.

Directory of Open Access Journals (Sweden)

Yasuaki eTamura

2016-05-01

Full Text Available Hsp90 is the most abundant cytosolic HSP and is known to act as a molecular chaperone. We found that an Hsp90-cancer antigen peptide complex was efficiently cross-presented by human monocyte-derived dendritic cells and induced peptide-specific cytotoxic T lymphocytes. Furthermore, we observed that the internalized Hsp90-peptide complex was strictly sorted to the Rab5+, EEA1+ static early endosome and the Hsp90-chaperoned peptide was processed and bound to MHC class I molecules through a endosome-recycling pathway. We also found that extracellular Hsp90 complexed with CpG-A or self-DNA stimulates production of a large amount of IFN-α from pDCs via static early endosome targeting. Thus, extracellular Hsp90 can target the antigen or nucleic acid to a static early endosome by spatio-temporal regulation. Moreover, we showed that Hsp90 associates with and delivers TLR7/9 from the ER to early endosomes for ligand recognition. Hsp90 inhibitor, geldanamycin derivative inhibited the Hsp90 association with TLR7/9, resulting in inhibition IFN-α production, leading to improvement of SLE symptoms. Interstingly, we observed that serum Hsp90 is clearly increased in patients with active SLE compared with that in patients with inactive disease. Serum Hsp90 detected in SLE patients binds to self-DNA and/or anti-DNA Ab, thus leading to stimulation of pDCs to produce IFN-α. Thus, Hsp90 plays a crucial role in the pathogenesis of SLE and that an Hsp90 inhibitor will therefore provide a new therapeutic approach to SLE and other nucleic acid-related autoimmune diseases. We will discuss how spatio-temporal regulation of Hsp90-ligand complexes within antigen-presenting cells affects the innate immunity and adaptive immunity.

Measurement of wavefront aberrations in cortex and peripheral nerve using a two-photon excitation guidestar

Science.gov (United States)

Futia, Gregory L.; Fontaine, Arjun; McCullough, Connor; Ozbay, Baris N.; George, Nickolas M.; Caldwell, John; Restrepo, Diego; Weir, Richard; Gibson, Emily A.

2018-02-01

Neural-machine interfaces using optogenetics are of interest due to their minimal invasiveness and potential for parallel read in and read out of activity. One possible biological target for such an interface is the peripheral nerve, where axonlevel imaging or stimulation could greatly improve interfacing with artificial limbs or enable neuron/fascicle level neuromodulation in the vagus nerve. Two-photon imaging has been successful in imaging brain activity using genetically encoded calcium or voltage indicators, but in the peripheral nerve, this is severely limited by scattering and aberrations from myelin. We employ a Shack-Hartman wavefront sensor and two-photon excitation guidestar to quantify optical scattering and aberrations in peripheral nerves and cortex. The sciatic and vagus nerves, and cortex from a ChAT-Cre ChR-eYFP transgenic mouse were excised and imaged directly. In peripheral nerves, defocus was the strongest aberration followed by astigmatism and coma. Peripheral nerve had orders of magnitude higher aberration compared with cortex. These results point to the potential of adaptive optics for increasing the depth of two-photon access into peripheral nerves.

Artificial spatiotemporal touch inputs reveal complementary decoding in neocortical neurons.

Science.gov (United States)

Oddo, Calogero M; Mazzoni, Alberto; Spanne, Anton; Enander, Jonas M D; Mogensen, Hannes; Bengtsson, Fredrik; Camboni, Domenico; Micera, Silvestro; Jörntell, Henrik

2017-04-04

Investigations of the mechanisms of touch perception and decoding has been hampered by difficulties in achieving invariant patterns of skin sensor activation. To obtain reproducible spatiotemporal patterns of activation of sensory afferents, we used an artificial fingertip equipped with an array of neuromorphic sensors. The artificial fingertip was used to transduce real-world haptic stimuli into spatiotemporal patterns of spikes. These spike patterns were delivered to the skin afferents of the second digit of rats via an array of stimulation electrodes. Combined with low-noise intra- and extracellular recordings from neocortical neurons in vivo, this approach provided a previously inaccessible high resolution analysis of the representation of tactile information in the neocortical neuronal circuitry. The results indicate high information content in individual neurons and reveal multiple novel neuronal tactile coding features such as heterogeneous and complementary spatiotemporal input selectivity also between neighboring neurons. Such neuronal heterogeneity and complementariness can potentially support a very high decoding capacity in a limited population of neurons. Our results also indicate a potential neuroprosthetic approach to communicate with the brain at a very high resolution and provide a potential novel solution for evaluating the degree or state of neurological disease in animal models.

Adaptive aberration correction using a triode hyperbolic electron mirror

International Nuclear Information System (INIS)

Fitzgerald, J.P.S.; Word, R.C.; Koenenkamp, R.

2011-01-01

A converging electron mirror can be used to compensate spherical and chromatic aberrations in an electron microscope. This paper presents an analytical solution to a novel triode (three electrode) hyperbolic mirror as an improvement to the well-known diode (two electrode) hyperbolic mirror for aberration correction. A weakness of the diode mirror is a lack of flexibility in changing the chromatic and spherical aberration coefficients independently without changes in the mirror geometry. In order to remove this limitation, a third electrode can be added. We calculate the optical properties of the resulting triode mirror analytically on the basis of a simple model field distribution. We present the optical properties-the object/image distance, z 0 , and the coefficients of spherical and chromatic aberration, C s and C c , of both mirror types from an analysis of electron trajectories in the mirror field. From this analysis, we demonstrate that while the properties of both designs are similar, the additional parameters in the triode mirror improve the range of aberration that can be corrected. The triode mirror is also able to provide a dynamic adjustment range of chromatic aberration for fixed spherical aberration and focal length, or any permutation of these three parameters. While the dynamic range depends on the values of aberration correction needed, a nominal 10% tuning range is possible for most configurations accompanied by less than 1% change in the other two properties. -- Highlights: → Electrostatic aberration correction for chromatic and spherical aberration in electron optics. → Simultaneous correction of spherical and chromatic aberrations over a wide, adjustable range. → Analytic and quantitative description of correction parameters.

Rooting Out Aberrant Behavior in Training.

Science.gov (United States)

Kokalis, Jerry, Jr.; Paquin, Dave

1989-01-01

Discusses aberrant, or disruptive, behavior in an industrial/business, classroom-based, instructor-led training setting. Three examples of aberrant behavior are described, typical case studies are provided for each, and preventive (long-term) and corrective (on-the-spot) strategies for dealing with the problems are discussed. (LRW)

The cerebellar Golgi cell and spatiotemporal organization of granular layer activity

Directory of Open Access Journals (Sweden)

Egidio eD‘Angelo

2013-05-01

Full Text Available The cerebellar granular layer has been suggested to perform a complex spatiotemporal reconfiguration of incoming mossy fiber signals. Central to this role is the inhibitory action exerted by Golgi cells over granule cells: Golgi cells inhibit granule cells through double feedforward and feedback inhibitory loops and generate a broad lateral inhibition that extends beyond the afferent synaptic field. This characteristic connectivity has recently been investigated in great detail and been correlated with specific functional properties of the neuron. These include theta-frequency pacemaking, network entrainment into coherent oscillations and phase resetting. Important advances have also been made in terms of determining the membrane and synaptic properties of the neuron, and clarifying the mechanisms of activation by input bursts. Moreover, voltage sensitive dye imaging and multi-electrode array recordings, combined with mathematical simulations based on realistic computational models, have improved our understanding of the impact of Golgi cell activity on granular layer circuit computations. These investigations have highlighted the critical role of Golgi cells in: generating dense clusters of granule cell activity organized in center-surround structures, implementing combinatorial operations on multiple mossy fiber inputs, regulating transmission gain and cut-off frequency, controlling spike timing and burst transmission, and determining the sign, intensity and extension of long-term synaptic plasticity at the mossy fiber-granule cell relay. This review considers recent advances in the field, highlighting the functional implications of Golgi cells for granular layer network computation and indicating new challenges for cerebellar research.

The correction of electron lens aberrations

Energy Technology Data Exchange (ETDEWEB)

Hawkes, P.W., E-mail: peter.hawkes@cemes.fr

2015-09-15

The progress of electron lens aberration correction from about 1990 onwards is chronicled. Reasonably complete lists of publications on this and related topics are appended. A present for Max Haider and Ondrej Krivanek in the year of their 65th birthdays. By a happy coincidence, this review was completed in the year that both Max Haider and Ondrej Krivanek reached the age of 65. It is a pleasure to dedicate it to the two leading actors in the saga of aberration corrector design and construction. They would both wish to associate their colleagues with such a tribute but it is the names of Haider and Krivanek (not forgetting Joachim Zach) that will remain in the annals of electron optics, next to that of Harald Rose. I am proud to know that both regard me as a friend as well as a colleague. - Highlights: • Geometrical aberration correction. • Chromatic aberration correction. • 50 pm resolution. • High-resolution electron energy-loss spectroscopy. • Extensive bibliographies.

The correction of electron lens aberrations

International Nuclear Information System (INIS)

Hawkes, P.W.

2015-01-01

The progress of electron lens aberration correction from about 1990 onwards is chronicled. Reasonably complete lists of publications on this and related topics are appended. A present for Max Haider and Ondrej Krivanek in the year of their 65th birthdays. By a happy coincidence, this review was completed in the year that both Max Haider and Ondrej Krivanek reached the age of 65. It is a pleasure to dedicate it to the two leading actors in the saga of aberration corrector design and construction. They would both wish to associate their colleagues with such a tribute but it is the names of Haider and Krivanek (not forgetting Joachim Zach) that will remain in the annals of electron optics, next to that of Harald Rose. I am proud to know that both regard me as a friend as well as a colleague. - Highlights: • Geometrical aberration correction. • Chromatic aberration correction. • 50 pm resolution. • High-resolution electron energy-loss spectroscopy. • Extensive bibliographies

Effects of Spatio-Temporal Aliasing on Pilot Performance in Active Control Tasks

Science.gov (United States)

Zaal, Peter; Sweet, Barbara

2010-01-01

Spatio-temporal aliasing affects pilot performance and control behavior. For increasing refresh rates: 1) Significant change in control behavior: a) Increase in visual gain and neuromuscular frequency. b) Decrease in visual time delay. 2) Increase in tracking performance: a) Decrease in RMSe. b) Increase in crossover frequency.

Spatiotemporal optical solitons

International Nuclear Information System (INIS)

Malomed, Boris A; Mihalache, Dumitru; Wise, Frank; Torner, Lluis

2005-01-01

In the course of the past several years, a new level of understanding has been achieved about conditions for the existence, stability, and generation of spatiotemporal optical solitons, which are nondiffracting and nondispersing wavepackets propagating in nonlinear optical media. Experimentally, effectively two-dimensional (2D) spatiotemporal solitons that overcome diffraction in one transverse spatial dimension have been created in quadratic nonlinear media. With regard to the theory, fundamentally new features of light pulses that self-trap in one or two transverse spatial dimensions and do not spread out in time, when propagating in various optical media, were thoroughly investigated in models with various nonlinearities. Stable vorticity-carrying spatiotemporal solitons have been predicted too, in media with competing nonlinearities (quadratic-cubic or cubic-quintic). This article offers an up-to-date survey of experimental and theoretical results in this field. Both achievements and outstanding difficulties are reviewed, and open problems are highlighted. Also briefly described are recent predictions for stable 2D and 3D solitons in Bose-Einstein condensates supported by full or low-dimensional optical lattices. (review article)

Patterning of inflorescences and flowers by the F-Box protein DOUBLE TOP and the LEAFY homolog ABERRANT LEAF AND FLOWER of petunia.

Science.gov (United States)

Souer, Erik; Rebocho, Alexandra B; Bliek, Mattijs; Kusters, Elske; de Bruin, Robert A M; Koes, Ronald

2008-08-01

Angiosperms display a wide variety of inflorescence architectures differing in the positions where flowers or branches arise. The expression of floral meristem identity (FMI) genes determines when and where flowers are formed. In Arabidopsis thaliana, this is regulated via transcription of LEAFY (LFY), which encodes a transcription factor that promotes FMI. We found that this is regulated in petunia (Petunia hybrida) via transcription of a distinct gene, DOUBLE TOP (DOT), a homolog of UNUSUAL FLORAL ORGANS (UFO) from Arabidopsis. Mutation of DOT or its tomato (Solanum lycopersicum) homolog ANANTHA abolishes FMI. Ubiquitous expression of DOT or UFO in petunia causes very early flowering and transforms the inflorescence into a solitary flower and leaves into petals. Ectopic expression of DOT or UFO together with LFY or its homolog ABERRANT LEAF AND FLOWER (ALF) in petunia seedlings activates genes required for identity or outgrowth of organ primordia. DOT interacts physically with ALF, suggesting that it activates ALF by a posttranslational mechanism. Our findings suggest a wider role than previously thought for DOT and UFO in the patterning of flowers and indicate that the different roles of LFY and UFO homologs in the spatiotemporal control of floral identity in distinct species result from their divergent expression patterns.

Third-rank chromatic aberrations of electron lenses.

Science.gov (United States)

Liu, Zhixiong

2018-02-01

In this paper the third-rank chromatic aberration coefficients of round electron lenses are analytically derived and numerically calculated by Mathematica. Furthermore, the numerical results are cross-checked by the differential algebraic (DA) method, which verifies that all the formulas for the third-rank chromatic aberration coefficients are completely correct. It is hoped that this work would be helpful for further chromatic aberration correction in electron microscopy. Copyright © 2017 Elsevier B.V. All rights reserved.

Carpal Tunnel Syndrome in Aberrant Muscle Syndrome: A Case Report and Review of the Literature.

Science.gov (United States)

Steele, Jessica; Coombs, Christopher

2018-06-01

Aberrant Muscle Syndrome (AMS) is a rare congenital hand difference that is characterised by unilateral non-progressive muscular hyperplasia. The aetiology of aberrant muscle syndrome is not known, but a recently published case has shown a somatic PIK3CA activating mutation in a patient with AMS. Carpal tunnel syndrome (CTS) in children is rare. The most common causes are the mucopolysaccaridoses but space-occupying lesions have also been reported to cause CTS in children. We report the first case of CTS in a child with AMS successfully treated with open carpal tunnel release and excision of aberrant muscles.

The Distribution of Chromosomal Aberrations in Human Cells Predicted by a Generalized Time-Dependent Model of Radiation-Induced Formation of Aberrations

Science.gov (United States)

Ponomarev, Artem L.; George, K.; Cucinotta, F. A.

2011-01-01

New experimental data show how chromosomal aberrations for low- and high-LET radiation are dependent on DSB repair deficiencies in wild-type, AT and NBS cells. We simulated the development of chromosomal aberrations in these cells lines in a stochastic track-structure-dependent model, in which different cells have different kinetics of DSB repair. We updated a previously formulated model of chromosomal aberrations, which was based on a stochastic Monte Carlo approach, to consider the time-dependence of DSB rejoining. The previous version of the model had an assumption that all DSBs would rejoin, and therefore we called it a time-independent model. The chromosomal-aberrations model takes into account the DNA and track structure for low- and high-LET radiations, and provides an explanation and prediction of the statistics of rare and more complex aberrations. We compared the program-simulated kinetics of DSB rejoining to the experimentally-derived bimodal exponential curves of the DSB kinetics. We scored the formation of translocations, dicentrics, acentric and centric rings, deletions, and inversions. The fraction of DSBs participating in aberrations was studied in relation to the rejoining time. Comparisons of simulated dose dependence for simple aberrations to the experimental dose-dependence for HF19, AT and NBS cells will be made.

Spatio-Temporal Data Exchange Standards

DEFF Research Database (Denmark)

Jensen, Christian Søndergaard; Schmidt, Albrecht

2003-01-01

We believe that research that concerns aspects of spatio-temporal data management may benefit from taking into account the various standards for spatio-temporal data formats. For example, this may contribute to rendering prototype software “open” and more readily useful. This paper thus identifies...... and briefly surveys standardization in relation to primarily the exchange and integration of spatio-temporal data. An overview of several data exchange languages is offered, along with reviews their potential for facilitating the collection of test data and the leveraging of prototypes. The standards, most...... of which are XML-based, lend themselves to the integration of prototypes into middleware architectures, e.g., as Web services....

Second-order analysis of structured inhomogeneous spatio-temporal point processes

DEFF Research Database (Denmark)

Møller, Jesper; Ghorbani, Mohammad

Statistical methodology for spatio-temporal point processes is in its infancy. We consider second-order analysis based on pair correlation functions and K-functions for first general inhomogeneous spatio-temporal point processes and second inhomogeneous spatio-temporal Cox processes. Assuming...... spatio-temporal separability of the intensity function, we clarify different meanings of second-order spatio-temporal separability. One is second-order spatio-temporal independence and relates e.g. to log-Gaussian Cox processes with an additive covariance structure of the underlying spatio......-temporal Gaussian process. Another concerns shot-noise Cox processes with a separable spatio-temporal covariance density. We propose diagnostic procedures for checking hypotheses of second-order spatio-temporal separability, which we apply on simulated and real data (the UK 2001 epidemic foot and mouth disease data)....

Chromosome aberrations in pesticide-exposed greenhouse workers

DEFF Research Database (Denmark)

Lander, B F; Knudsen, Lisbeth E.; Gamborg, M O

2000-01-01

OBJECTIVES: The aim of this study was to investigate the possibility of subtoxic exposure to pesticides causing chromosome aberrations in greenhouse workers. METHODS: In a cross-sectional and prospective study design chromosome aberration frequencies in cultured lymphocytes were examined for 116...... greenhouse workers exposed to a complex mixture of almost 50 insecticides, fungicides, and growth regulators and also for 29 nonsmoking, nonpesticide-exposed referents. RESULTS: The preseason frequencies of chromosome aberrations were slightly but not statistically significantly elevated for the greenhouse...... workers when they were compared with the referents. After a summer season of pesticide spraying in the greenhouses, the total frequencies of cells with chromosome aberrations were significantly higher than in the preseason samples (P=0.02) and also higher than for the referents (P=0.05). This finding...

Aberration-free intraocular lenses - What does this really mean?

Science.gov (United States)

Langenbucher, Achim; Schröder, Simon; Cayless, Alan; Eppig, Timo

2017-09-01

So-called aberration-free intraocular lenses (IOLs) are well established in modern cataract surgery. Usually, they are designed to perfectly refract a collimated light beam onto the focal point. We show how much aberration can be expected with such an IOL in a convergent light beam such as that found anterior to the human cornea. Additionally, the aberration in a collimated beam is estimated for an IOL that has no aberrations in the convergent beam. The convergent beam is modelled as the pencil of rays corresponding to the spherical wavefront resulting from a typical corneal power of 43m -1 . The IOLs are modelled as infinitely thin phase plates with 20m -1 optical power placed 5mm behind the cornea. Their aberrations are reported in terms of optical path length difference and longitudinal spherical aberration (LSA) of the marginal rays, as well as nominal spherical aberration (SA) calculated based on a Zernike representation of the wavefront-error at the corneal plane within a 6mm aperture. The IOL designed to have no aberrations in a collimated light beam has an optical path length difference of -1.8μm, and LSA of 0.15m -1 in the convergent beam of a typical eye. The corresponding nominal SA is 0.065μm. The IOL designed to have no aberrations in a convergent light beam has an optical path length difference of 1.8μm, and LSA of -0.15m -1 in the collimated beam. An IOL designed to have no aberrations in a collimated light beam will increase the SA of a patient's eye after implantation. Copyright © 2017. Published by Elsevier GmbH.

Phyllanthus emblica Fruit Extract Activates Spindle Assembly Checkpoint, Prevents Mitotic Aberrations and Genomic Instability in Human Colon Epithelial NCM460 Cells

Directory of Open Access Journals (Sweden)

Xihan Guo

2016-09-01

Full Text Available The fruit of Phyllanthus emblica Linn. (PE has been widely consumed as a functional food and folk medicine in Southeast Asia due to its remarkable nutritional and pharmacological effects. Previous research showed PE delays mitotic progress and increases genomic instability (GIN in human colorectal cancer cells. This study aimed to investigate the similar effects of PE by the biomarkers related to spindle assembly checkpoint (SAC, mitotic aberrations and GIN in human NCM460 normal colon epithelial cells. Cells were treated with PE and harvested differently according to the biomarkers observed. Frequencies of micronuclei (MN, nucleoplasmic bridge (NPB and nuclear bud (NB in cytokinesis-block micronucleus assay were used as indicators of GIN. Mitotic aberrations were assessed by the biomarkers of chromosome misalignment, multipolar division, chromosome lagging and chromatin bridge. SAC activity was determined by anaphase-to- metaphase ratio (AMR and the expression of core SAC gene budding uninhibited by benzimidazoles related 1 (BubR1. Compared with the control, PE-treated cells showed (1 decreased incidences of MN, NPB and NB (p < 0.01; (2 decreased frequencies of all mitotic aberration biomarkers (p < 0.01; and (3 decreased AMR (p < 0.01 and increased BubR1 expression (p < 0.001. The results revealed PE has the potential to protect human normal colon epithelial cells from mitotic and genomic damages partially by enhancing the function of SAC.

The enemy within: propagation of aberrant corticostriatal learning to cortical function in Parkinson's disease

Directory of Open Access Journals (Sweden)

Jeff A Beeler

2013-09-01

Full Text Available Motor dysfunction in Parkinson’s disease is believed to arise primarily from pathophysiology in the dorsal striatum and its related corticostriatal and thalamostriatal circuits during progressive dopamine denervation. One function of these circuits is to provide a filter that selectively facilitates or inhibits cortical activity to optimize cortical processing, making motor responses rapid and efficient. Corticostriatal synaptic plasticity mediates the learning that underlies this performance-optimizing filter. Under dopamine denervation, corticostriatal plasticity is altered, resulting in aberrant learning that induces inappropriate basal ganglia filtering that impedes rather than optimizes cortical processing. Human imaging suggests that increased cortical activity may compensate for striatal dysfunction in PD patients. In this Perspective article, we consider how aberrant learning at corticostriatal synapses may impair cortical processing and learning and undermine potential cortical compensatory mechanisms. Blocking or remediating aberrant corticostriatal plasticity may protect cortical function and support cortical compensatory mechanisms mitigating the functional decline associated with progressive dopamine denervation.

Image transfer with spatial coherence for aberration corrected transmission electron microscopes

International Nuclear Information System (INIS)

Hosokawa, Fumio; Sawada, Hidetaka; Shinkawa, Takao; Sannomiya, Takumi

2016-01-01

The formula of spatial coherence involving an aberration up to six-fold astigmatism is derived for aberration-corrected transmission electron microscopy. Transfer functions for linear imaging are calculated using the newly derived formula with several residual aberrations. Depending on the symmetry and origin of an aberration, the calculated transfer function shows characteristic symmetries. The aberrations that originate from the field’s components, having uniformity along the z direction, namely, the n-fold astigmatism, show rotational symmetric damping of the coherence. The aberrations that originate from the field’s derivatives with respect to z, such as coma, star, and three lobe, show non-rotational symmetric damping. It is confirmed that the odd-symmetric wave aberrations have influences on the attenuation of an image via spatial coherence. Examples of image simulations of haemoglobin and Si [211] are shown by using the spatial coherence for an aberration-corrected electron microscope. - Highlights: • The formula of partial coherence for aberration corrected TEM is derived. • Transfer functions are calculated with several residual aberrations. • The calculated transfer function shows the characteristic damping. • The odd-symmetric wave aberrations can cause the attenuation of image via coherence. • The examples of aberration corrected TEM image simulations are shown.

Image transfer with spatial coherence for aberration corrected transmission electron microscopes

Energy Technology Data Exchange (ETDEWEB)

Hosokawa, Fumio, E-mail: hosokawa@bio-net.co.jp [BioNet Ltd., 2-3-28 Nishikityo, Tachikwa, Tokyo (Japan); Tokyo Institute of Technology, 4259 Nagatsuta, Midoriku, Yokohama 226-8503 (Japan); Sawada, Hidetaka [JEOL (UK) Ltd., JEOL House, Silver Court, Watchmead, Welwyn Garden City, Herts AL7 1LT (United Kingdom); Shinkawa, Takao [BioNet Ltd., 2-3-28 Nishikityo, Tachikwa, Tokyo (Japan); Sannomiya, Takumi [Tokyo Institute of Technology, 4259 Nagatsuta, Midoriku, Yokohama 226-8503 (Japan)

2016-08-15

The formula of spatial coherence involving an aberration up to six-fold astigmatism is derived for aberration-corrected transmission electron microscopy. Transfer functions for linear imaging are calculated using the newly derived formula with several residual aberrations. Depending on the symmetry and origin of an aberration, the calculated transfer function shows characteristic symmetries. The aberrations that originate from the field’s components, having uniformity along the z direction, namely, the n-fold astigmatism, show rotational symmetric damping of the coherence. The aberrations that originate from the field’s derivatives with respect to z, such as coma, star, and three lobe, show non-rotational symmetric damping. It is confirmed that the odd-symmetric wave aberrations have influences on the attenuation of an image via spatial coherence. Examples of image simulations of haemoglobin and Si [211] are shown by using the spatial coherence for an aberration-corrected electron microscope. - Highlights: • The formula of partial coherence for aberration corrected TEM is derived. • Transfer functions are calculated with several residual aberrations. • The calculated transfer function shows the characteristic damping. • The odd-symmetric wave aberrations can cause the attenuation of image via coherence. • The examples of aberration corrected TEM image simulations are shown.

Effect of aberrations in human eye on contrast sensitivity function

Science.gov (United States)

Quan, Wei; Wang, Feng-lin; Wang, Zhao-qi

2011-06-01

The quantitative analysis of the effect of aberrations in human eye on vision has important clinical value in the correction of aberrations. The wave-front aberrations of human eyes were measured with the Hartmann-Shack wave-front sensor and modulation transfer function (MTF) was computed from the wave-front aberrations. Contrast sensitivity function (CSF) was obtained from MTF and the retinal aerial image modulation (AIM). It is shown that the 2nd, 3rd, 4th, 5th, 6th Zernike aberrations deteriorate contrast sensitivity function. When the 2nd, 3rd, 4th, 5th, 6th Zernike aberrations are corrected high contrast sensitivity function can be obtained.

Clinimetric properties of the Tinetti Mobility Test, Four Square Step Test, Activities-specific Balance Confidence Scale, and spatiotemporal gait measures in individuals with Huntington's disease.

Science.gov (United States)

Kloos, Anne D; Fritz, Nora E; Kostyk, Sandra K; Young, Gregory S; Kegelmeyer, Deb A

2014-09-01

Individuals with Huntington's disease (HD) experience balance and gait problems that lead to falls. Clinicians currently have very little information about the reliability and validity of outcome measures to determine the efficacy of interventions that aim to reduce balance and gait impairments in HD. This study examined the reliability and concurrent validity of spatiotemporal gait measures, the Tinetti Mobility Test (TMT), Four Square Step Test (FSST), and Activities-specific Balance Confidence (ABC) Scale in individuals with HD. Participants with HD [n = 20; mean age ± SD=50.9 ± 13.7; 7 male] were tested on spatiotemporal gait measures and the TMT, FSST, and ABC Scale before and after a six week period to determine test-retest reliability and minimal detectable change (MDC) values. Linear relationships between gait and clinical measures were estimated using Pearson's correlation coefficients. Spatiotemporal gait measures, the TMT total and the FSST showed good to excellent test-retest reliability (ICC > 0.75). MDC values were 0.30 m/s and 0.17 m/s for velocity in forward and backward walking respectively, four points for the TMT, and 3s for the FSST. The TMT and FSST were highly correlated with most spatiotemporal measures. The ABC Scale demonstrated lower reliability and less concurrent validity than other measures. The high test-retest reliability over a six week period and concurrent validity between the TMT, FSST, and spatiotemporal gait measures suggest that the TMT and FSST may be useful outcome measures for future intervention studies in ambulatory individuals with HD. Copyright © 2014 Elsevier B.V. All rights reserved.

Aberrant Intrinsic Activity and Connectivity in Cognitively Normal Parkinson's Disease.

Science.gov (United States)

Harrington, Deborah L; Shen, Qian; Castillo, Gabriel N; Filoteo, J Vincent; Litvan, Irene; Takahashi, Colleen; French, Chelsea

2017-01-01

, rather than compensatory influence on cognitive abilities tested in this study. Receiver operating curve analyses demonstrated excellent sensitivity (≥90%) of rsfMRI variables in distinguishing patients from controls, but poor accuracy for brain volume and cognitive variables. Altogether these results provide new insights into the topology, cognitive relevance, and sensitivity of aberrant intrinsic activity and connectivity that precedes clinically significant cognitive impairment. Longitudinal studies are needed to determine if these neurocognitive associations presage the development of future mild cognitive impairment or dementia.

Chromosome aberration analysis for biological dosimetry: a review

International Nuclear Information System (INIS)

Paul, S.F.D.; Venkatachalam, P.; Jeevanram, R.K.

1996-01-01

Among various biological dosimetry techniques, dicentric chromosome aberration method appears to be the method of choice in analysing accidental radiation exposure in most of the laboratories. The major advantage of this method is its sensitivity as the number of dicentric chromosomes present in control population is too small and more importantly radiation induces mainly dicentric chromosome aberration among unstable aberration. This report brings out the historical development of various cytogenetic methods, the basic structure of DNA, chromosomes and different forms of chromosome aberrations. It also highlights the construction of dose-response curve for dicentric chromosome and its use in the estimation of radiation dose. (author)

Wave aberrations in rhesus monkeys with vision-induced ametropias

Science.gov (United States)

Ramamirtham, Ramkumar; Kee, Chea-su; Hung, Li-Fang; Qiao-Grider, Ying; Huang, Juan; Roorda, Austin; Smith, Earl L.

2007-01-01

The purpose of this study was to investigate the relationship between refractive errors and high-order aberrations in infant rhesus monkeys. Specifically, we compared the monochromatic wave aberrations measured with a Shack-Hartman wavefront sensor between normal monkeys and monkeys with vision-induced refractive errors. Shortly after birth, both normal monkeys and treated monkeys reared with optically induced defocus or form deprivation showed a decrease in the magnitude of high-order aberrations with age. However, the decrease in aberrations was typically smaller in the treated animals. Thus, at the end of the lens-rearing period, higher than normal amounts of aberrations were observed in treated eyes, both hyperopic and myopic eyes and treated eyes that developed astigmatism, but not spherical ametropias. The total RMS wavefront error increased with the degree of spherical refractive error, but was not correlated with the degree of astigmatism. Both myopic and hyperopic treated eyes showed elevated amounts of coma and trefoil and the degree of trefoil increased with the degree of spherical ametropia. Myopic eyes also exhibited a much higher prevalence of positive spherical aberration than normal or treated hyperopic eyes. Following the onset of unrestricted vision, the amount of high-order aberrations decreased in the treated monkeys that also recovered from the experimentally induced refractive errors. Our results demonstrate that high-order aberrations are influenced by visual experience in young primates and that the increase in high-order aberrations in our treated monkeys appears to be an optical byproduct of the vision-induced alterations in ocular growth that underlie changes in refractive error. The results from our study suggest that the higher amounts of wave aberrations observed in ametropic humans are likely to be a consequence, rather than a cause, of abnormal refractive development. PMID:17825347

The Art of Optical Aberrations

Science.gov (United States)

Wylde, Clarissa Eileen Kenney

Art and optics are inseparable. Though seemingly opposite disciplines, the combination of art and optics has significantly impacted both culture and science as they are now known. As history has run its course, in the sciences, arts, and their fruitful combinations, optical aberrations have proved to be a problematic hindrance to progress. In an effort to eradicate aberrations the simple beauty of these aberrational forms has been labeled as undesirable and discarded. Here, rather than approach aberrations as erroneous, these beautiful forms are elevated to be the photographic subject in a new body of work, On the Bright Side. Though many recording methods could be utilized, this work was composed on classic, medium-format, photographic film using white-light, Michelson interferometry. The resulting images are both a representation of the true light rays that interacted on the distorted mirror surfaces (data) and the artist's compositional eye for what parts of the interferogram are chosen and displayed. A detailed description of the captivating interdisciplinary procedure is documented and presented alongside the final artwork, CCD digital reference images, and deformable mirror contour maps. This alluring marriage between the arts and sciences opens up a heretofore minimally explored aspect of the inextricable art-optics connection. It additionally provides a fascinating new conversation on the importance of light and optics in photographic composition.

Aberration design of zoom lens systems using thick lens modules.

Science.gov (United States)

Zhang, Jinkai; Chen, Xiaobo; Xi, Juntong; Wu, Zhuoqi

2014-12-20

A systematic approach for the aberration design of a zoom lens system using a thick lens module is presented. Each component is treated as a thick lens module at the beginning of the design. A thick lens module refers to a thick lens component with a real lens structure, like lens materials, lens curvatures, lens thicknesses, and lens interval distances. All nine third-order aberrations of a thick lens component are considered during the design. The relationship of component aberrations in different zoom positions can be approximated from the aberration shift. After minimizing the aberrations of the zoom lens system, the nine third-order aberrations of every lens component can be determined. Then the thick lens structure of every lens component can be determined after optimization according to their first-order properties and third-order aberration targets. After a third optimization for minimum practical third-order aberrations of a zoom lens system, the aberration design using the thick lens module is complete, which provides a practical zoom lens system with thick lens structures. A double-sided telecentric zoom lens system is designed using the thick lens module in this paper, which shows that this method is practical for zoom lens design.

Aspects of second-order analysis of structured inhomogeneous spatio-temporal processes

DEFF Research Database (Denmark)

Møller, Jesper; Ghorbani, Mohammad

2012-01-01

Statistical methodology for spatio-temporal point processes is in its infancy. We consider second-order analysis based on pair correlation functions and K-functions for general inhomogeneous spatio-temporal point processes and for inhomogeneous spatio-temporal Cox processes. Assuming spatio......-temporal separability of the intensity function, we clarify different meanings of second-order spatio-temporal separability. One is second-order spatio-temporal independence and relates to log-Gaussian Cox processes with an additive covariance structure of the underlying spatio-temporal Gaussian process. Another...... concerns shot-noise Cox processes with a separable spatio-temporal covariance density. We propose diagnostic procedures for checking hypotheses of second-order spatio-temporal separability, which we apply on simulated and real data....

SPATIO-TEMPORAL CHARACTERISTICS OF RESIDENT TRIP BASED ON POI AND OD DATA OF FLOAT CAR IN BEIJING

OpenAIRE

N. Mou; N. Mou; J. Li; L. Zhang; W. Liu; Y. Xu

2017-01-01

Due to the influence of the urban inherent regional functional distribution, the daily activities of the residents presented some spatio-temporal patterns (periodic patterns, gathering patterns, etc.). In order to further understand the spatial and temporal characteristics of urban residents, this paper research takes the taxi trajectory data of Beijing as a sample data and studies the spatio-temporal characteristics of the residents' activities on the weekdays. At first, according t...

Aberrant Modulation of Brain Oscillatory Activity and Attentional Impairment in Attention-Deficit/Hyperactivity Disorder.

Science.gov (United States)

Lenartowicz, Agatha; Mazaheri, Ali; Jensen, Ole; Loo, Sandra K

2018-01-01

Electroencephalography and magnetoencephalography are noninvasive neuroimaging techniques that have been used extensively to study various resting-state and cognitive processes in the brain. The purpose of this review is to highlight a number of recent studies that have investigated the alpha band (8-12 Hz) oscillatory activity present in magnetoencephalography and electroencephalography, to provide new insights into the maladaptive network activity underlying attentional impairments in attention-deficit/hyperactivity disorder (ADHD). Studies reviewed demonstrate that event-related decrease in alpha is attenuated during visual selective attention, primarily in ADHD inattentive type, and is often significantly associated with accuracy and reaction time during task performance. Furthermore, aberrant modulation of alpha activity has been reported across development and may have abnormal or atypical lateralization patterns in ADHD. Modulations in the alpha band thus represent a robust, relatively unexplored putative biomarker of attentional impairment and a strong prospect for future studies aimed at examining underlying neural mechanisms and treatment response among individuals with ADHD. Potential limitations of its use as a diagnostic biomarker and directions for future research are discussed. Copyright © 2017 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Third-order monochromatic aberrations via Fermat's principle

International Nuclear Information System (INIS)

Marasco, A.; Romano, A.

2006-01-01

By Fermat's principle and particular optical paths, which are not rays, a new aberration function is introduced. This function allows to derive, without resorting to the whole Hamiltonian formalism, the third-order geometrical aberrations of an optical system with a symmetry of revolution

SPATIOTEMPORAL CONTRAST SENSITIVITY OF EARLY VISION

NARCIS (Netherlands)

Hateren, J.H. van

Based on the spatial and temporal statistics of natural images, a theory is developed that specifies spatiotemporal filters that maximize the flow of information through noisy channels of limited dynamic range. Sensitivities resulting from these spatiotemporal filters are very similar to the human

Catadioptric aberration correction in cathode lens microscopy

Energy Technology Data Exchange (ETDEWEB)

Tromp, R.M. [IBM T.J. Watson Research Center, PO Box 218, Yorktown Heights, NY 10598 (United States); Kamerlingh Onnes Laboratory, Leiden Institute of Physics, Niels Bohrweg 2, 2333 CA Leiden (Netherlands)

2015-04-15

In this paper I briefly review the use of electrostatic electron mirrors to correct the aberrations of the cathode lens objective lens in low energy electron microscope (LEEM) and photo electron emission microscope (PEEM) instruments. These catadioptric systems, combining electrostatic lens elements with a reflecting mirror, offer a compact solution, allowing simultaneous and independent correction of both spherical and chromatic aberrations. A comparison with catadioptric systems in light optics informs our understanding of the working principles behind aberration correction with electron mirrors, and may point the way to further improvements in the latter. With additional developments in detector technology, 1 nm spatial resolution in LEEM appears to be within reach. - Highlights: • The use of electron mirrors for aberration correction in LEEM/PEEM is reviewed. • A comparison is made with similar systems in light optics. • Conditions for 1 nm spatial resolution are discussed.

Radiation-induced chromosome aberrations in the rat peripheral blood

International Nuclear Information System (INIS)

Ziemba-Zoltowska, B.; Bocian, E.; Radwan, I.; Rosiek, O.; Sablinski, J.

1978-01-01

Chromosome aberrations in rat lymphocytes of peripheral blood after X (in vitro and in vivo) and 3 H tritiated water (in vivo) irradiations were studied. The yield of chromosome aberrations after in vivo and in vitro exposure to X-rays was similar. The frequency of chromosome aberrations three weeks after exposure to X-rays and soon after irradiation was practically on the same level. The yield of chromosome aberrations determined three weeks after injection with tritiated water or X-rays exposure was similar. (author)

Chromosomal aberrations in bone marrow of continuously irradiated rats

Energy Technology Data Exchange (ETDEWEB)

Chlebosky, O; Praslicka, M; Chlebovska, K [Univerzita P.J. Safarika, Kosice (Czechoslovakia). Prirodovedecka Fakulta

1975-01-01

Research on chromosomal aberrations of the bone marrow in continuously irradiated rats showed that chromosomal aberrations are a highly sensitive indicator of radiation injury. An increase in the chromosomal aberration frequency was already found on the 5th day at daily doses of 0.5 R, i.e. a 12% increase at a total dose of 25 R. In the steady-state stage at daily doses of 0.5; 1; 2.5 R, the number of chromosomal aberrations stabilized at values of about 20%; at daily doses of 5 and 10 R at values of 30.=., at daily doses of 53 R at 45%, at a daily dose of 82.5 R, the number of chromosomal aberrations increased to 55%.

Aberration-corrected STEM/TEM imaging at 15 kV

International Nuclear Information System (INIS)

Sasaki, Takeo; Sawada, Hidetaka; Hosokawa, Fumio; Sato, Yuta; Suenaga, Kazu

2014-01-01

The performance of aberration-corrected (scanning) transmission electron microscopy (S/TEM) at an accelerating voltage of 15 kV was evaluated in a low-voltage microscope equipped with a cold-field emission gun and a higher-order aberration corrector. Aberrations up to the fifth order were corrected by the aberration measurement and auto-correction system using the diffractogram tableau method in TEM and Ronchigram analysis in STEM. TEM observation of nanometer-sized particles demonstrated that aberrations up to an angle of 50 mrad were compensated. A TEM image of Si[110] exhibited lattice fringes with a spacing of 0.192 nm, and the power spectrum of the image showed spots corresponding to distances of 0.111 nm. An annular dark-field STEM image of Si[110] showed lattice fringes of (111) and (22¯0) planes corresponding to lattice distances of 0.314 nm and 0.192 nm, respectively. At an accelerating voltage of 15 kV, the developed low-voltage microscope achieved atomic-resolution imaging with a small chromatic aberration and a large uniform phase. - Highlights: • Aberration-corrected STEM/TEM imaging at 15 kV demonstrated lattice fringes of Si[110] single crystal with a spacing of 0.192 nm. • To achieve this performance at a lower accelerating voltage, uniform phase area over 50 mrad is mandatory in Ronchigram and Diffractogram tableau. • This means a higher-order aberration of six-fold astigmatism should be compensated. • In addition, decreasing the effect of chromatic aberration plays an important role for improving the performance of linear scattering component at 15 kV TEM

Estimation of dose from chromosome aberration rate

International Nuclear Information System (INIS)

Li Deping

1990-01-01

The methods and skills of evaluating dose from correctly scored shromsome aberration rate are presented, and supplemented with corresponding BASIC computer code. The possibility and preventive measures of excessive probability of missing score of the aberrations in some of the current routine score methods are discussed. The use of dose-effect relationship with exposure time correction factor G in evaluating doses and their confidence intervals, dose estimation in mixed n-γ exposure, and identification of high by nonuniform acute exposure to low LET radiation and its dose estimation are discussed in more detail. The difference of estimated dose due to whether the interaction between subleisoms produced by n and γ have been taken into account is examined. In fitting the standard dose-aberration rate curve, proper weighing of experiment points and comparison with commonly accepted values are emphasised, and the coefficient of variation σ y √y of the aberration rate y as a function of dose and exposure time is given. In appendix I and II, the dose-aberration rate formula is derived from dual action theory, and the time variation of subleisom is illustrated and in appendix III, the estimation of dose from scores of two different types of aberrations (of other related score) is illustrated. Two computer codes are given in appendix IV, one is a simple code, the other a complete code, including the fitting of standard curve. the skills of using compressed data storage, and the production of simulated 'data ' for testing the curve fitting procedure are also given

Aberration of a negative ion beam caused by space charge effect

International Nuclear Information System (INIS)

Miyamoto, K.; Wada, S.; Hatayama, A.

2010-01-01

Aberrations are inevitable when the charged particle beams are extracted, accelerated, transmitted, and focused with electrostatic and magnetic fields. In this study, we investigate the aberration of a negative ion accelerator for a neutral beam injector theoretically, especially the spherical aberration caused by the negative ion beam expansion due to the space charge effect. The negative ion current density profiles with the spherical aberration are compared with those without the spherical aberration. It is found that the negative ion current density profiles in a log scale are tailed due to the spherical aberration.

Aberration of a negative ion beam caused by space charge effect

Energy Technology Data Exchange (ETDEWEB)

Miyamoto, K. [Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan); Wada, S.; Hatayama, A. [Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)

2010-02-15

Aberrations are inevitable when the charged particle beams are extracted, accelerated, transmitted, and focused with electrostatic and magnetic fields. In this study, we investigate the aberration of a negative ion accelerator for a neutral beam injector theoretically, especially the spherical aberration caused by the negative ion beam expansion due to the space charge effect. The negative ion current density profiles with the spherical aberration are compared with those without the spherical aberration. It is found that the negative ion current density profiles in a log scale are tailed due to the spherical aberration.

Aberration of a negative ion beam caused by space charge effect.

Science.gov (United States)

Miyamoto, K; Wada, S; Hatayama, A

2010-02-01

Aberrations are inevitable when the charged particle beams are extracted, accelerated, transmitted, and focused with electrostatic and magnetic fields. In this study, we investigate the aberration of a negative ion accelerator for a neutral beam injector theoretically, especially the spherical aberration caused by the negative ion beam expansion due to the space charge effect. The negative ion current density profiles with the spherical aberration are compared with those without the spherical aberration. It is found that the negative ion current density profiles in a log scale are tailed due to the spherical aberration.

Aberrant regeneration of the third cranial nerve.

Science.gov (United States)

Shrestha, U D; Adhikari, S

2012-01-01

Aberrant regeneration of the third cranial nerve is most commonly due to its damage by trauma. A ten-month old child presented with the history of a fall from a four-storey building. She developed traumatic third nerve palsy and eventually the clinical features of aberrant regeneration of the third cranial nerve. The adduction of the eye improved over time. She was advised for patching for the strabismic amblyopia as well. Traumatic third nerve palsy may result in aberrant regeneration of the third cranial nerve. In younger patients, motility of the eye in different gazes may improve over time. © NEPjOPH.

Transverse correlation vanishing due to phase aberrations

CSIR Research Space (South Africa)

Godin, T

2011-06-01

Full Text Available of the effects of each aberration on the ratio Sp ?? / , the following condition are imposed: 0max3max2max1 )()()( ??????? === . (9) It is assumed that the phase aberration is set in the beam-waist plane of radius mmW 5.10 = . Arbitrarily, the value... of max? is fixed to twice the incident beam width, 0max 2W=? , where the intensity is only 0.03% of the on-axis value. In the following we will express the aberration 0? in number of equivalent wavelengths given by the ratio )2/(00 pi...

Frequencies of chromosome aberration on radiation workers

International Nuclear Information System (INIS)

Yanti Lusiyanti; Zubaidah Alatas

2016-01-01

Radiation exposure of the body can cause damage to the genetic material in cells (cytogenetic) in the form of changes in the structure or chromosomal aberrations in peripheral blood lymphocytes. Chromosomal aberrations can be unstable as dicentric and ring chromosomes, and is stable as translocation. Dicentric chromosome is the gold standard biomarker due to radiation exposure, and chromosome translocation is a biomarker for retrospective biodosimetry. The aim of this studi is to conduct examination of chromosomal aberrations in the radiation worker to determine the potential damage of cell that may arise due to occupational radiation exposure. The examination have been carried out on blood samples from 55 radiation workers in the range of 5-30 year of service. Chromosome aberration frequency measurement starts with blood sampling, culturing, harvesting, slide preparations, and lymphocyte chromosome staining with Giemsa and painting with Fluorescence In Situ Hybridization (FISH) technique. The results showed that chromosomal translocations are not found in blood samples radiation workers and dicentric chromosomes found only on 2 blood samples of radiation workers with a frequency of 0.001/cell. The frequency of chromosomal aberrations in the blood cells such workers within normal limits and this means that the workers have been implemented a radiation safety aspects very well. (author)

Ocular higher-order aberrations in a school children population

Directory of Open Access Journals (Sweden)

George Papamastorakis

2015-04-01

Conclusions: Differences in the low levels of ocular spherical aberration in young children possibly reflect differences in lenticular spherical aberration and relate to the gradient refractive index of the lens. The evaluation of spherical aberration at certain stages of eye growth may help to better understand the underlying mechanisms of myopia development.

Short curcumin treatment modulates oxidative stress, arginase activity, aberrant crypt foci, and TGF-β1 and HES-1 transcripts in 1,2-dimethylhydrazine-colon carcinogenesis in mice

International Nuclear Information System (INIS)

Bounaama, Abdelkader; Djerdjouri, Bahia; Laroche-Clary, Audrey; Le Morvan, Valérie; Robert, Jacques

2012-01-01

Highlights: ► 1,2-Dimethylhydrazine (DMH) toxicity was driven by oxidative stress. ► Arginase activity correlated to aberrant crypt foci (ACF). ► Curcumin diet restored redox status and induced apoptosis of dysplastic ACF. ► Curcumin reduced arginase activity and up regulated TGF-β1 and HES-1 transcripts. -- Abstract: This study investigated the effect of short curcumin treatment, a natural antioxidant on 1,2-dimethylhydrazine (DMH)-induced aberrant crypt foci (ACF) in mice. The incidence of aberrant crypt foci (ACF) was 100%, with 54 ± 6 per colon, 10 weeks after the first DMH injection and reached 67 ± 12 per colon after 12 weeks. A high level of undifferentiated goblet cells and a weak apoptotic activity were shown in dysplastic ACF. The morphological alterations of colonic mucosa were associated to severe oxidative stress ratio with 43% increase in malondialdehyde vs. 36% decrease in GSH. DMH also increased inducible nitric synthase (iNOS) mRNA transcripts (250%), nitrites level (240%) and arginase activity (296%), leading to nitrosative stress and cell proliferation. Curcumin treatment, starting at week 10 post-DMH injection for 14 days, reduced the number of ACF (40%), iNOS expression (25%) and arginase activity (73%), and improved redox status by approximately 46%, compared to DMH-treated mice. Moreover, curcumin induced apoptosis of dysplastic ACF cells without restoring goblet cells differentiation. Interestingly, curcumin induced a parallel increase in TGF-β1 and HES-1 transcripts (42% and 26%, respectively). In conclusion, the protective effect of curcumin was driven by the reduction of arginase activity and nitrosative stress. The up regulation of TGF-β1 and HES-1 expression by curcumin suggests for the first time, a potential interplay between these signalling pathways in the chemoprotective mechanism of curcumin.

A Flexible Spatio-Temporal Model for Air Pollution with Spatial and Spatio-Temporal Covariates

OpenAIRE

Lindström, Johan; Szpiro, Adam A; Sampson, Paul D; Oron, Assaf P; Richards, Mark; Larson, Tim V; Sheppard, Lianne

2013-01-01

The development of models that provide accurate spatio-temporal predictions of ambient air pollution at small spatial scales is of great importance for the assessment of potential health effects of air pollution. Here we present a spatio-temporal framework that predicts ambient air pollution by combining data from several different monitoring networks and deterministic air pollution model(s) with geographic information system (GIS) covariates. The model presented in this paper has been implem...

Fifth-order canonical geometric aberration analysis of electrostatic round lenses

CERN Document Server

Liu Zhi Xiong

2002-01-01

In this paper the fifth-order canonical geometric aberration patterns are analyzed and a numerical example is given on the basis of the analytical expressions of fifth-order aberration coefficients derived in the present work. The fifth-order spherical aberration, astigmatism and field curvature, and distortion are similar to the third-order ones and the fifth-order coma is slightly different. Besides, there are two more aberrations which do not exist in the third-order aberration: they are peanut aberration and elliptical coma in accordance with their shapes. In the numerical example, by using a cross-check of the calculated coefficients with those computed through the differential algebraic method, it has been verified that all the expressions are correct and the computational results are reliable with high precision.

Chromosomal aberrations induced by alpha particles

International Nuclear Information System (INIS)

Guerrero C, C.; Brena V, M.

2005-01-01

The chromosomal aberrations produced by the ionizing radiation are commonly used when it is necessary to establish the exposure dose of an individual, it is a study that is used like complement of the traditional physical systems and its application is only in cases in that there is doubt about what indicates the conventional dosimetry. The biological dosimetry is based on the frequency of aberrations in the chromosomes of the lymphocytes of the individual in study and the dose is calculated taking like reference to the dose-response curves previously generated In vitro. A case of apparent over-exposure to alpha particles to which is practiced analysis of chromosomal aberrations to settle down if in fact there was exposure and as much as possible, to determine the presumed dose is presented. (Author)

Spherical aberration and other higher-order aberrations in the human eye : from summary wave-front analysis data to optical variables relevant to visual perception

NARCIS (Netherlands)

Jansonius, Nomdo M.

Wave-front analysis data from the human eye are commonly presented using the aberration coefficient c(4)(0) (primary spherical aberration) together with an overall measure of all higher-order aberrations. If groups of subjects are compared, however, the relevance of an observed difference cannot

Statistical estimation of ultrasonic propagation path parameters for aberration correction.

Science.gov (United States)

Waag, Robert C; Astheimer, Jeffrey P

2005-05-01

Parameters in a linear filter model for ultrasonic propagation are found using statistical estimation. The model uses an inhomogeneous-medium Green's function that is decomposed into a homogeneous-transmission term and a path-dependent aberration term. Power and cross-power spectra of random-medium scattering are estimated over the frequency band of the transmit-receive system by using closely situated scattering volumes. The frequency-domain magnitude of the aberration is obtained from a normalization of the power spectrum. The corresponding phase is reconstructed from cross-power spectra of subaperture signals at adjacent receive positions by a recursion. The subapertures constrain the receive sensitivity pattern to eliminate measurement system phase contributions. The recursion uses a Laplacian-based algorithm to obtain phase from phase differences. Pulse-echo waveforms were acquired from a point reflector and a tissue-like scattering phantom through a tissue-mimicking aberration path from neighboring volumes having essentially the same aberration path. Propagation path aberration parameters calculated from the measurements of random scattering through the aberration phantom agree with corresponding parameters calculated for the same aberrator and array position by using echoes from the point reflector. The results indicate the approach describes, in addition to time shifts, waveform amplitude and shape changes produced by propagation through distributed aberration under realistic conditions.

Emergent dynamics of spatio-temporal chaos in a heterogeneous excitable medium.

Science.gov (United States)

Bittihn, Philip; Berg, Sebastian; Parlitz, Ulrich; Luther, Stefan

2017-09-01

Self-organized activation patterns in excitable media such as spiral waves and spatio-temporal chaos underlie dangerous cardiac arrhythmias. While the interaction of single spiral waves with different types of heterogeneity has been studied extensively, the effect of heterogeneity on fully developed spatio-temporal chaos remains poorly understood. We investigate how the complexity and stability properties of spatio-temporal chaos in the Bär-Eiswirth model of excitable media depend on the heterogeneity of the underlying medium. We employ different measures characterizing the chaoticity of the system and find that the spatial arrangement of multiple discrete lower excitability regions has a strong impact on the complexity of the dynamics. Varying the number, shape, and spatial arrangement of the heterogeneities, we observe strong emergent effects ranging from increases in chaoticity to the complete cessation of chaos, contrasting the expectation from the homogeneous behavior. The implications of our findings for the development and treatment of arrhythmias in the heterogeneous cardiac muscle are discussed.

Higher order aberrations of the eye: Part one

Directory of Open Access Journals (Sweden)

Marsha Oberholzer

2016-06-01

Full Text Available This article is the first in a series of two articles that provide a comprehensive literature review of higher order aberrations (HOAs of the eye. The present article mainly explains the general principles of such HOAs as well as HOAs of importance, and the measuring apparatus used to measure HOAs of the eye. The second article in the series discusses factors contributing to variable results in measurements of HOAs of the eye. Keywords: Higher order aberrations; wavefront aberrations; aberrometer

The mechanism by which a propeptide-encoded pH sensor regulates spatiotemporal activation of furin.

Science.gov (United States)

Williamson, Danielle M; Elferich, Johannes; Ramakrishnan, Parvathy; Thomas, Gary; Shinde, Ujwal

2013-06-28

The proprotein convertase furin requires the pH gradient of the secretory pathway to regulate its multistep, compartment-specific autocatalytic activation. Although His-69 within the furin prodomain serves as the pH sensor that detects transport of the propeptide-enzyme complex to the trans-Golgi network, where it promotes cleavage and release of the inhibitory propeptide, a mechanistic understanding of how His-69 protonation mediates furin activation remains unclear. Here we employ biophysical, biochemical, and computational approaches to elucidate the mechanism underlying the pH-dependent activation of furin. Structural analyses and binding experiments comparing the wild-type furin propeptide with a nonprotonatable His-69 → Leu mutant that blocks furin activation in vivo revealed protonation of His-69 reduces both the thermodynamic stability of the propeptide as well as its affinity for furin at pH 6.0. Structural modeling combined with mathematical modeling and molecular dynamic simulations suggested that His-69 does not directly contribute to the propeptide-enzyme interface but, rather, triggers movement of a loop region in the propeptide that modulates access to the cleavage site and, thus, allows for the tight pH regulation of furin activation. Our work establishes a mechanism by which His-69 functions as a pH sensor that regulates compartment-specific furin activation and provides insights into how other convertases and proteases may regulate their precise spatiotemporal activation.

The Mechanism by Which a Propeptide-encoded pH Sensor Regulates Spatiotemporal Activation of Furin*

Science.gov (United States)

Williamson, Danielle M.; Elferich, Johannes; Ramakrishnan, Parvathy; Thomas, Gary; Shinde, Ujwal

2013-01-01

The proprotein convertase furin requires the pH gradient of the secretory pathway to regulate its multistep, compartment-specific autocatalytic activation. Although His-69 within the furin prodomain serves as the pH sensor that detects transport of the propeptide-enzyme complex to the trans-Golgi network, where it promotes cleavage and release of the inhibitory propeptide, a mechanistic understanding of how His-69 protonation mediates furin activation remains unclear. Here we employ biophysical, biochemical, and computational approaches to elucidate the mechanism underlying the pH-dependent activation of furin. Structural analyses and binding experiments comparing the wild-type furin propeptide with a nonprotonatable His-69 → Leu mutant that blocks furin activation in vivo revealed protonation of His-69 reduces both the thermodynamic stability of the propeptide as well as its affinity for furin at pH 6.0. Structural modeling combined with mathematical modeling and molecular dynamic simulations suggested that His-69 does not directly contribute to the propeptide-enzyme interface but, rather, triggers movement of a loop region in the propeptide that modulates access to the cleavage site and, thus, allows for the tight pH regulation of furin activation. Our work establishes a mechanism by which His-69 functions as a pH sensor that regulates compartment-specific furin activation and provides insights into how other convertases and proteases may regulate their precise spatiotemporal activation. PMID:23653353

Bayesian spatiotemporal model of fMRI data using transfer functions.

Science.gov (United States)

Quirós, Alicia; Diez, Raquel Montes; Wilson, Simon P

2010-09-01

This research describes a new Bayesian spatiotemporal model to analyse BOLD fMRI studies. In the temporal dimension, we describe the shape of the hemodynamic response function (HRF) with a transfer function model. The spatial continuity and local homogeneity of the evoked responses are modelled by a Gaussian Markov random field prior on the parameter indicating activations. The proposal constitutes an extension of the spatiotemporal model presented in a previous approach [Quirós, A., Montes Diez, R. and Gamerman, D., 2010. Bayesian spatiotemporal model of fMRI data, Neuroimage, 49: 442-456], offering more flexibility in the estimation of the HRF and computational advantages in the resulting MCMC algorithm. Simulations from the model are performed in order to ascertain the performance of the sampling scheme and the ability of the posterior to estimate model parameters, as well as to check the model sensitivity to signal to noise ratio. Results are shown on synthetic data and on a real data set from a block-design fMRI experiment. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Spatiotemporal expression of endogenous opioid processing enzymes in mouse uterus at peri-implantation.

Science.gov (United States)

Wu, Weiwei; Kong, Shuangbo; Wang, Bingyan; Chen, Yongjie; Wang, Haibin

2016-02-01

Successful implantation requires intimate interactions between a competent blastocyst and a receptive uterus. We recently demonstrated that the aberrant activation of opioid signaling by exogenous ligands adversely affects preimplantation embryonic development and subsequent implantation in mice. However, the underlying machinery governing the dynamic homeostasis of the endogenous opioid system in the uterus during early pregnancy remains elusive. We now show that all three major endogenous opioid precursors are spatiotemporally expressed in the uterus during early pregnancy. Moreover, we observe the well-coordinated expression of the synthetic enzyme prohormone convertases 1/3 (PC1/3) at lower levels and of its inhibitor proprotein convertase subtilisin/kexin type 1 inhibitor (Pcsk1n) and the degrading enzyme membrane metallo-endopeptidase (MME) at higher levels in the receptive uterus. Both estrogen and progestin tend to reduce the uterine levels of opioid ligand precursors in the ovariectomized mouse model. This tight regulation of the endogenous opioid system by PC1/3, Pcsk1n and MME has been further confirmed in physiologically related pseudopregnancy and delayed implantation mouse models. The coordinated regulation of opioid precursor biosynthesis and metabolism helps to create appropriate opioid signaling ensuring uterine receptivity for implantation. Thus, endogenous uterine opioid levels are primarily determined by the coordinated expressions of PC1/3, Pcsk1n and MME under the influence of ovarian progestin and estrogen. Our findings raise an additional cautionary note regarding the effects of opioid abuse on early pregnancy events.

Analysis of Relations between Spatiotemporal Movement Regulation and Performance of Discrete Actions Reveals Functionality in Skilled Climbing.

Science.gov (United States)

Orth, Dominic; Kerr, Graham; Davids, Keith; Seifert, Ludovic

2017-01-01

In this review of research on climbing expertise, we focus on different measures of climbing performance, including spatiotemporal measures related to fluency and activity states (i.e., discrete actions), adopted by climbers for achieving overall performance goals of getting to the end of a route efficiently and safely. Currently, a broad range of variables have been reported, however, many of these fail to capture how climbers adapt to a route whilst climbing. We argue that spatiotemporal measures should be considered concurrently with evaluation of activity states (such as reaching or exploring) in order gain a more comprehensive picture of how climbers successfully adapt to a route. Spatial and temporal movement measures taken at the hip are a traditional means of assessing efficiency of climbing behaviors. More recently, performatory and exploratory actions of the limbs have been used in combination with spatiotemporal indicators, highlighting the influence of limb states on climbing efficiency and skill transfer. However, only a few studies have attempted to combine spatiotemporal and activity state measures taken during route climbing. This review brings together existing approaches for observing climbing skill at performance outcome (i.e., spatiotemporal assessments) and process (i.e., limb activity states) levels of analysis. Skill level is associated with a spatially efficient route progression and lower levels of immobility. However, more difficult hold architecture designs require significantly greater mobility and more complex movement patterning to maintain performance. Different forms of functional, or goal-supportive, movement variability, including active recovery and hold exploration, have been implicated as important adaptations to physiological and environmental dynamics that emerge during the act of climbing. Indeed, recently it has also been shown that, when climbing on new routes, efficient exploration can improve the transfer of skill. This

Effect of spherical aberration on scintillations of Gaussian beams in atmospheric turbulence

International Nuclear Information System (INIS)

Ji, Xiaoling; Deng, Jinping

2014-01-01

The effect of spherical aberration on scintillations of Gaussian beams in weak, moderate and strong turbulence is studied using numerical simulation method. It is found that the effect of the negative spherical aberration on the on-axis scintillation index is quite different from that of the positive spherical aberration. In weak turbulence, the positive spherical aberration results in a decrease of the on-axis scintillation index on propagation, but the negative spherical aberration results in an increase of the on-axis scintillation index when the propagation distance is not large. In particular, in weak turbulence the negative spherical aberration may cause peaks of the on-axis scintillation index, and the peaks disappear in moderate and strong turbulence, which is explained in physics. The strong turbulence leads to less discrepancy among scintillations of Gaussian beams with and without spherical aberration. - Highlights: • In weak turbulence scintillations can be suppressed using positive spherical aberration. • In weak turbulence scintillations may be very large due to negative spherical aberration. • The effect of spherical aberration on scintillations is less with increasing of turbulence

Effect of spherical aberration on scintillations of Gaussian beams in atmospheric turbulence

Energy Technology Data Exchange (ETDEWEB)

Ji, Xiaoling, E-mail: jiXL100@163.com; Deng, Jinping

2014-07-18

The effect of spherical aberration on scintillations of Gaussian beams in weak, moderate and strong turbulence is studied using numerical simulation method. It is found that the effect of the negative spherical aberration on the on-axis scintillation index is quite different from that of the positive spherical aberration. In weak turbulence, the positive spherical aberration results in a decrease of the on-axis scintillation index on propagation, but the negative spherical aberration results in an increase of the on-axis scintillation index when the propagation distance is not large. In particular, in weak turbulence the negative spherical aberration may cause peaks of the on-axis scintillation index, and the peaks disappear in moderate and strong turbulence, which is explained in physics. The strong turbulence leads to less discrepancy among scintillations of Gaussian beams with and without spherical aberration. - Highlights: • In weak turbulence scintillations can be suppressed using positive spherical aberration. • In weak turbulence scintillations may be very large due to negative spherical aberration. • The effect of spherical aberration on scintillations is less with increasing of turbulence.

Influence of Misalignment on High-Order Aberration Correction for Normal Human Eyes

Science.gov (United States)

Zhao, Hao-Xin; Xu, Bing; Xue, Li-Xia; Dai, Yun; Liu, Qian; Rao, Xue-Jun

2008-04-01

Although a compensation device can correct aberrations of human eyes, the effect will be degraded by its misalignment, especially for high-order aberration correction. We calculate the positioning tolerance of correction device for high-order aberrations, and within what degree the correcting effect is better than low-order aberration (defocus and astigmatism) correction. With fixed certain misalignment within the positioning tolerance, we calculate the residual wavefront rms aberration of the first-6 to first-35 terms along with the 3rd-5th terms of aberrations corrected, and the combined first-13 terms of aberrations are also studied under the same quantity of misalignment. However, the correction effect of high-order aberrations does not meliorate along with the increase of the high-order terms under some misalignment, moreover, some simple combined terms correction can achieve similar result as complex combinations. These results suggest that it is unnecessary to correct too much the terms of high-order aberrations which are difficult to accomplish in practice, and gives confidence to correct high-order aberrations out of the laboratory.

Influence of Misalignment on High-Order Aberration Correction for Normal Human Eyes

International Nuclear Information System (INIS)

Hao-Xin, Zhao; Bing, Xu; Li-Xia, Xue; Yun, Dai; Qian, Liu; Xue-Jun, Rao

2008-01-01

Although a compensation device can correct aberrations of human eyes, the effect will be degraded by its misalignment, especially for high-order aberration correction. We calculate the positioning tolerance of correction device for high-order aberrations, and within what degree the correcting effect is better than low-order aberration (defocus and astigmatism) correction. With fixed certain misalignment within the positioning tolerance, we calculate the residual wavefront rms aberration of the first-6 to first-35 terms along with the 3rd-5th terms of aberrations corrected, and the combined first-13 terms of aberrations are also studied under the same quantity of misalignment. However, the correction effect of high-order aberrations does not meliorate along with the increase of the high-order terms under some misalignment, moreover, some simple combined terms correction can achieve similar result as complex combinations. These results suggest that it is unnecessary to correct too much the terms of high-order aberrations which are difficult to accomplish in practice, and gives confidence to correct high-order aberrations out of the laboratory

Possible mechanisms of chromosomal aberrations: VII. Comparative dynamics of sister chromatid disjunction and realization of radiation-induced chromosomal aberrations during mitosis

International Nuclear Information System (INIS)

Lebedeva, L.I.; Akhmamet'eva, E.M.

1994-01-01

An increase in radiation-induced chromosomal aberrations during c-metaphase sister chromatid disjunction was demonstrated in murine bone marrow cells exposed to a total γ-irradiation at 0.5 Gy. Caffeine (Cf) treatment during mitosis partially suppressed the chromatid disjunction rate and increased the number of radiation-induced aberrations in this mitosis. Nalidixic acid (NA) treatment of c-metaphase cells completely suppressed chromatid disjunction and the realization of induced aberrations. Topoisomerase 2 was assumed to be involved during mitosis in both processes

Chromosome aberration analysis based on a beta-binomial distribution

International Nuclear Information System (INIS)

Otake, Masanori; Prentice, R.L.

1983-10-01

Analyses carried out here generalized on earlier studies of chromosomal aberrations in the populations of Hiroshima and Nagasaki, by allowing extra-binomial variation in aberrant cell counts corresponding to within-subject correlations in cell aberrations. Strong within-subject correlations were detected with corresponding standard errors for the average number of aberrant cells that were often substantially larger than was previously assumed. The extra-binomial variation is accomodated in the analysis in the present report, as described in the section on dose-response models, by using a beta-binomial (B-B) variance structure. It is emphasized that we have generally satisfactory agreement between the observed and the B-B fitted frequencies by city-dose category. The chromosomal aberration data considered here are not extensive enough to allow a precise discrimination between competing dose-response models. A quadratic gamma ray and linear neutron model, however, most closely fits the chromosome data. (author)

Spatio-Temporal Data Construction

Directory of Open Access Journals (Sweden)

Hai Ha Le

2013-08-01

Full Text Available On the route to a spatio-temporal geoscience information system, an appropriate data model for geo-objects in space and time has been developed. In this model, geo-objects are represented as sequences of geometries and properties with continuous evolution in each time interval. Because geomodeling software systems usually model objects at specific time instances, we want to interpolate the geometry and properties from two models of an object with only geometrical constraints (no physical or mechanical constraints. This process is called spatio-temporal data construction or morphological interpolation of intermediate geometries. This paper is strictly related to shape morphing, shape deformation, cross-parameterization and compatible remeshing and is only concerned with geological surfaces. In this study, two main sub-solutions construct compatible meshes and find trajectories in which vertices of the mesh evolve. This research aims to find an algorithm to construct spatio-temporal data with some constraints from the geosciences, such as cutting surfaces by faulting or fracturing phenomena and evolving boundaries attached to other surfaces. Another goal of this research is the implementation of the algorithm in a software product, namely a gOcad plug-in. The four main procedures of the algorithm are cutting the surfaces, setting up constraints, partitioning and calculating the parameterizations and trajectories. The software has been tested to construct data for a salt dome and other surfaces in regard to the geological processes of faulting, deposition and erosion. The result of this research is an algorithm and software for the construction of spatio-temporal data.

Chromosome aberrations: plants to human and Feulgen to FISH

International Nuclear Information System (INIS)

Natarajan, A.T.

2005-01-01

Chromosome aberrations and their impact on human health have been recognized for a long time. In the 1950s, in India, studies on induced chromosome aberrations in plants were initiated by Swaminathan and his students. I trace here the impact of these initial studies on further developments in this field. The studies which were started in plants have been extended to mammals (including human) and the simple squash and solid staining have been improved by molecular cytogenetic techniques, thus enabling accurate identification and quantification of different types of chromosome aberrations. These studies have also thrown light on the mechanisms of chromosome aberration formation, especially following exposure to ionizing radiation. (author)

Spatiotemporal trends of illegal activities from ranger-collected data in a Ugandan national park.

Science.gov (United States)

Critchlow, R; Plumptre, A J; Driciru, M; Rwetsiba, A; Stokes, E J; Tumwesigye, C; Wanyama, F; Beale, C M

2015-10-01

Within protected areas, biodiversity loss is often a consequence of illegal resource use. Understanding the patterns and extent of illegal activities is therefore essential for effective law enforcement and prevention of biodiversity declines. We used extensive data, commonly collected by ranger patrols in many protected areas, and Bayesian hierarchical models to identify drivers, trends, and distribution of multiple illegal activities within the Queen Elizabeth Conservation Area (QECA), Uganda. Encroachment (e.g., by pastoralists with cattle) and poaching of noncommercial animals (e.g., snaring bushmeat) were the most prevalent illegal activities within the QECA. Illegal activities occurred in different areas of the QECA. Poaching of noncommercial animals was most widely distributed within the national park. Overall, ecological covariates, although significant, were not useful predictors for occurrence of illegal activities. Instead, the location of illegal activities in previous years was more important. There were significant increases in encroachment and noncommercial plant harvesting (nontimber products) during the study period (1999-2012). We also found significant spatiotemporal variation in the occurrence of all activities. Our results show the need to explicitly model ranger patrol effort to reduce biases from existing uncorrected or capture per unit effort analyses. Prioritization of ranger patrol strategies is needed to target illegal activities; these strategies are determined by protected area managers, and therefore changes at a site-level can be implemented quickly. These strategies should also be informed by the location of past occurrences of illegal activity: the most useful predictor of future events. However, because spatial and temporal changes in illegal activities occurred, regular patrols throughout the protected area, even in areas of low occurrence, are also required. © 2015 Society for Conservation Biology.

Radiation-induced cellular reproductive death and chromosome aberrations

International Nuclear Information System (INIS)

Bedford, J.S.; Mitchell, J.B.; Griggs, H.G.; Bender, M.A.

1978-01-01

If a major mode of cell killing by ionizing radiation is the death of cells containing visible chromosomal aberrations, as for example from anaphase-bridge formation at mitosis, then cells bearing such aberrations should be selectively eliminated from the population, resulting in an increased survival potential for the population remaining at each succeeding cell generation. Using synchronized V79B Chinese hamster cells, we measured the aberration frequency and the colony-forming ability of mitotic cells at each of the first three generations following irradiation in G1. Cells were resynchronized by mechanial harvest at each succeeding mitosis after irradiation in order to avoid mixing of generations in the cell population at later sampling times. As anticipated, the chromosome aberration frequencies decreased markedly from the first to the second and from the second to the third mitosis. The surviving fraction, however, was virtually the same for plating assays carried out immediately after irradiation, at the first, or at the second mitosis. The surviving fraction was significantly higher for cells reaching the third postirradiation mitosis. Survival and aberration frequencies were assayed again at approximately the fourteenth postirradiation division, by which time the irradiated and control populations were not significantly different

Theory of aberration fields for general optical systems with freeform surfaces.

Science.gov (United States)

Fuerschbach, Kyle; Rolland, Jannick P; Thompson, Kevin P

2014-11-03

This paper utilizes the framework of nodal aberration theory to describe the aberration field behavior that emerges in optical systems with freeform optical surfaces, particularly φ-polynomial surfaces, including Zernike polynomial surfaces, that lie anywhere in the optical system. If the freeform surface is located at the stop or pupil, the net aberration contribution of the freeform surface is field constant. As the freeform optical surface is displaced longitudinally away from the stop or pupil of the optical system, the net aberration contribution becomes field dependent. It is demonstrated that there are no new aberration types when describing the aberration fields that arise with the introduction of freeform optical surfaces. Significantly it is shown that the aberration fields that emerge with the inclusion of freeform surfaces in an optical system are exactly those that have been described by nodal aberration theory for tilted and decentered optical systems. The key contribution here lies in establishing the field dependence and nodal behavior of each freeform term that is essential knowledge for effective application to optical system design. With this development, the nodes that are distributed throughout the field of view for each aberration type can be anticipated and targeted during optimization for the correction or control of the aberrations in an optical system with freeform surfaces. This work does not place any symmetry constraints on the optical system, which could be packaged in a fully three dimensional geometry, without fold mirrors.

Aberrant internal carotid artery in the middle ear

Energy Technology Data Exchange (ETDEWEB)

Roh, Keun Tak; Kang, Hyun Koo [Dept. of Radiology, Seoul Veterans Hospital, Seoul (Korea, Republic of)

2014-10-15

The knowledge about the aberrant internal carotid artery (ICA) in the middle ear is essential for clinicians, because a misdiagnosis of the aberrant ICA could have serious consequences such as excessive aural bleeding during a middle ear surgery. A 38-year-old woman presented with tinnitus and hearing difficulties of the left ear that had started 5 years ago. During otoscopy, an anteroinferior bluish mass was seen in the tympanic space. Computed tomography and magnetic resonance imaging demonstrated a left-side aberrant ICA with bony dehiscence of the carotid canal in the middle ear and a reduced diameter of the tympanic ICA. Herein we report a case of an aberrant ICA in the middle ear. We also review the literature regarding this important vascular anomaly of the temporal bone which may lead to disastrous surgical complications.

Aberrant internal carotid artery in the middle ear

International Nuclear Information System (INIS)

Roh, Keun Tak; Kang, Hyun Koo

2014-01-01

The knowledge about the aberrant internal carotid artery (ICA) in the middle ear is essential for clinicians, because a misdiagnosis of the aberrant ICA could have serious consequences such as excessive aural bleeding during a middle ear surgery. A 38-year-old woman presented with tinnitus and hearing difficulties of the left ear that had started 5 years ago. During otoscopy, an anteroinferior bluish mass was seen in the tympanic space. Computed tomography and magnetic resonance imaging demonstrated a left-side aberrant ICA with bony dehiscence of the carotid canal in the middle ear and a reduced diameter of the tympanic ICA. Herein we report a case of an aberrant ICA in the middle ear. We also review the literature regarding this important vascular anomaly of the temporal bone which may lead to disastrous surgical complications.

Transcriptome Analysis Reveals Markers of Aberrantly Activated Innate Immunity in Vitiligo Lesional and Non-Lesional Skin

Science.gov (United States)

Huang, Yuanshen; Wang, Yang; Yu, Jie; Gao, Min; Levings, Megan; Wei, Shencai; Zhang, Shengquan; Xu, Aie; Su, Mingwan; Dutz, Jan; Zhang, Xuejun; Zhou, Youwen

2012-01-01

Background Vitiligo is characterized by the death of melanocytes in the skin. This is associated with the presence of T cell infiltrates in the lesional borders. However, at present, there is no detailed and systematic characterization on whether additional cellular or molecular changes are present inside vitiligo lesions. Further, it is unknown if the normal appearing non-lesional skin of vitiligo patients is in fact normal. The purpose of this study is to systematically characterize the molecular and cellular characteristics of the lesional and non-lesional skin of vitiligo patients. Methods and Materials Paired lesional and non-lesional skin biopsies from twenty-three vitiligo patients and normal skin biopsies from sixteen healthy volunteers were obtained with informed consent. The following aspects were analyzed: (1) transcriptome changes present in vitiligo skin using DNA microarrays and qRT-PCR; (2) abnormal cellular infiltrates in vitiligo skin explant cultures using flow cytometry; and (3) distribution of the abnormal cellular infiltrates in vitiligo skin using immunofluorescence microscopy. Results Compared with normal skin, vitiligo lesional skin contained 17 genes (mostly melanocyte-specific genes) whose expression was decreased or absent. In contrast, the relative expression of 13 genes was up-regulated. The up-regulated genes point to aberrant activity of the innate immune system, especially natural killer cells in vitiligo. Strikingly, the markers of heightened innate immune responses were also found to be up-regulated in the non-lesional skin of vitiligo patients. Conclusions and Clinical Implications As the first systematic transcriptome characterization of the skin in vitiligo patients, this study revealed previously unknown molecular markers that strongly suggest aberrant innate immune activation in the microenvironment of vitiligo skin. Since these changes involve both lesional and non-lesional skin, our results suggest that therapies targeting

An aberrant precision account of autism.

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Rebecca P Lawson

2014-05-01

Full Text Available Autism is a neurodevelopmental disorder characterised by problems with social-communication, restricted interests and repetitive behaviour. A recent and controversial article presented a compelling normative explanation for the perceptual symptoms of autism in terms of a failure of Bayesian inference (Pellicano and Burr, 2012. In response, we suggested that when Bayesian interference is grounded in its neural instantiation – namely, predictive coding – many features of autistic perception can be attributed to aberrant precision (or beliefs about precision within the context of hierarchical message passing in the brain (Friston et al., 2013. Here, we unpack the aberrant precision account of autism. Specifically, we consider how empirical findings – that speak directly or indirectly to neurobiological mechanisms – are consistent with the aberrant encoding of precision in autism; in particular, an imbalance of the precision ascribed to sensory evidence relative to prior beliefs.

The Voronoi spatio-temporal data structure

Science.gov (United States)

Mioc, Darka

2002-04-01

Current GIS models cannot integrate the temporal dimension of spatial data easily. Indeed, current GISs do not support incremental (local) addition and deletion of spatial objects, and they can not support the temporal evolution of spatial data. Spatio-temporal facilities would be very useful in many GIS applications: harvesting and forest planning, cadastre, urban and regional planning, and emergency planning. The spatio-temporal model that can overcome these problems is based on a topological model---the Voronoi data structure. Voronoi diagrams are irregular tessellations of space, that adapt to spatial objects and therefore they are a synthesis of raster and vector spatial data models. The main advantage of the Voronoi data structure is its local and sequential map updates, which allows us to automatically record each event and performed map updates within the system. These map updates are executed through map construction commands that are composed of atomic actions (geometric algorithms for addition, deletion, and motion of spatial objects) on the dynamic Voronoi data structure. The formalization of map commands led to the development of a spatial language comprising a set of atomic operations or constructs on spatial primitives (points and lines), powerful enough to define the complex operations. This resulted in a new formal model for spatio-temporal change representation, where each update is uniquely characterized by the numbers of newly created and inactivated Voronoi regions. This is used for the extension of the model towards the hierarchical Voronoi data structure. In this model, spatio-temporal changes induced by map updates are preserved in a hierarchical data structure that combines events and corresponding changes in topology. This hierarchical Voronoi data structure has an implicit time ordering of events visible through changes in topology, and it is equivalent to an event structure that can support temporal data without precise temporal

Nonlinear Spatio-Temporal Dynamics and Chaos in Semiconductors

Science.gov (United States)

Schöll, Eckehard

2005-08-01

Nonlinear transport phenomena are an increasingly important aspect of modern semiconductor research. This volume deals with complex nonlinear dynamics, pattern formation, and chaotic behavior in such systems. It bridges the gap between two well-established fields: the theory of dynamic systems and nonlinear charge transport in semiconductors. This unified approach helps reveal important electronic transport instabilities. The initial chapters lay a general framework for the theoretical description of nonlinear self-organized spatio-temporal patterns, such as current filaments, field domains, fronts, and analysis of their stability. Later chapters consider important model systems in detail: impact ionization induced impurity breakdown, Hall instabilities, superlattices, and low-dimensional structures. State-of-the-art results include chaos control, spatio-temporal chaos, multistability, pattern selection, activator-inhibitor kinetics, and global coupling, linking fundamental issues to electronic device applications. This book will be of great value to semiconductor physicists and nonlinear scientists alike.

Image based method for aberration measurement of lithographic tools

Science.gov (United States)

Xu, Shuang; Tao, Bo; Guo, Yongxing; Li, Gongfa

2018-01-01

Information of lens aberration of lithographic tools is important as it directly affects the intensity distribution in the image plane. Zernike polynomials are commonly used for a mathematical description of lens aberrations. Due to the advantage of lower cost and easier implementation of tools, image based measurement techniques have been widely used. Lithographic tools are typically partially coherent systems that can be described by a bilinear model, which entails time consuming calculations and does not lend a simple and intuitive relationship between lens aberrations and the resulted images. Previous methods for retrieving lens aberrations in such partially coherent systems involve through-focus image measurements and time-consuming iterative algorithms. In this work, we propose a method for aberration measurement in lithographic tools, which only requires measuring two images of intensity distribution. Two linear formulations are derived in matrix forms that directly relate the measured images to the unknown Zernike coefficients. Consequently, an efficient non-iterative solution is obtained.

Cell survival and radiation induced chromosome aberrations. Pt. 2

International Nuclear Information System (INIS)

Bauchinger, M.; Schmid, E.; Braselmann, H.

1986-01-01

Human peripheral lymphocytes were irradiated in whole blood with 0.5-4.0 Gy of 220 kVp X-rays and the frequency of chromosome aberrations was determined in 1st or 2nd division metaphases discriminated by fluorescence plus giemsa staining. Using the empirical distributions of aberrations among cells, cell survival and transmission of aberrations were investigated. Considering both daughter cells, we found that 20% of fragments and 55% of dicentrics or ring chromosomes are lost during the 1st cell division; i.e. cell survival rate from 1st to 2nd generation is mainly influenced by anaphase bridging of these two-hit aberrations. Cell survival to 2nd mitosis was calculated considering this situation and compared with the survival derived from the fraction of M1 cells without unstable aberrations. The resulting shouldered survival curves showed significantly different slopes, indicating that cell reproductive death is overestimated in the latter approach. (orig.)

Revisiting Cross-Channel Information Transfer for Chromatic Aberration Correction

KAUST Repository

Sun, Tiancheng; Peng, Yifan; Heidrich, Wolfgang

2017-01-01

Image aberrations can cause severe degradation in image quality for consumer-level cameras, especially under the current tendency to reduce the complexity of lens designs in order to shrink the overall size of modules. In simplified optical designs, chromatic aberration can be one of the most significant causes for degraded image quality, and it can be quite difficult to remove in post-processing, since it results in strong blurs in at least some of the color channels. In this work, we revisit the pixel-wise similarity between different color channels of the image and accordingly propose a novel algorithm for correcting chromatic aberration based on this cross-channel correlation. In contrast to recent weak prior-based models, ours uses strong pixel-wise fitting and transfer, which lead to significant quality improvements for large chromatic aberrations. Experimental results on both synthetic and real world images captured by different optical systems demonstrate that the chromatic aberration can be significantly reduced using our approach.

Revisiting Cross-Channel Information Transfer for Chromatic Aberration Correction

KAUST Repository

Sun, Tiancheng

2017-12-25

Image aberrations can cause severe degradation in image quality for consumer-level cameras, especially under the current tendency to reduce the complexity of lens designs in order to shrink the overall size of modules. In simplified optical designs, chromatic aberration can be one of the most significant causes for degraded image quality, and it can be quite difficult to remove in post-processing, since it results in strong blurs in at least some of the color channels. In this work, we revisit the pixel-wise similarity between different color channels of the image and accordingly propose a novel algorithm for correcting chromatic aberration based on this cross-channel correlation. In contrast to recent weak prior-based models, ours uses strong pixel-wise fitting and transfer, which lead to significant quality improvements for large chromatic aberrations. Experimental results on both synthetic and real world images captured by different optical systems demonstrate that the chromatic aberration can be significantly reduced using our approach.

Aberrant innate immune activation following tissue injury impairs pancreatic regeneration.

Directory of Open Access Journals (Sweden)

Alexandra E Folias

development of chronic inflammation arises from aberrant activation of the innate inflammatory response. Collectively these studies identify targetable inflammatory factors that can be used to influence the development of non-resolving inflammation and pancreatic regeneration following injury.

Aberrant Intrinsic Activity and Connectivity in Cognitively Normal Parkinson’s Disease

Directory of Open Access Journals (Sweden)

Deborah L. Harrington

2017-06-01

pathological, rather than compensatory influence on cognitive abilities tested in this study. Receiver operating curve analyses demonstrated excellent sensitivity (≥90% of rsfMRI variables in distinguishing patients from controls, but poor accuracy for brain volume and cognitive variables. Altogether these results provide new insights into the topology, cognitive relevance, and sensitivity of aberrant intrinsic activity and connectivity that precedes clinically significant cognitive impairment. Longitudinal studies are needed to determine if these neurocognitive associations presage the development of future mild cognitive impairment or dementia.

Working memory load-dependent spatio-temporal activity of single-trial P3 response detected with an adaptive wavelet denoiser.

Science.gov (United States)

Zhang, Qiushi; Yang, Xueqian; Yao, Li; Zhao, Xiaojie

2017-03-27

Working memory (WM) refers to the holding and manipulation of information during cognitive tasks. Its underlying neural mechanisms have been explored through both functional magnetic resonance imaging (fMRI) and electroencephalography (EEG). Trial-by-trial coupling of simultaneously collected EEG and fMRI signals has become an important and promising approach to study the spatio-temporal dynamics of such cognitive processes. Previous studies have demonstrated a modulation effect of the WM load on both the BOLD response in certain brain areas and the amplitude of P3. However, much remains to be explored regarding the WM load-dependent relationship between the amplitude of ERP components and cortical activities, and the low signal-to-noise ratio (SNR) of the EEG signal still poses a challenge to performing single-trial analyses. In this paper, we investigated the spatio-temporal activities of P3 during an n-back verbal WM task by introducing an adaptive wavelet denoiser into the extraction of single-trial P3 features and using general linear model (GLM) to integrate simultaneously collected EEG and fMRI data. Our results replicated the modulation effect of the WM load on the P3 amplitude. Additionally, the activation of single-trial P3 amplitudes was detected in multiple brain regions, including the insula, the cuneus, the lingual gyrus (LG), and the middle occipital gyrus (MOG). Moreover, we found significant correlations between P3 features and behavioral performance. These findings suggest that the single-trial integration of simultaneous EEG and fMRI signals may provide new insights into classical cognitive functions. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

Higher-Order Wavefront Aberrations for Populations of Young Emmetropes and Myopes

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Jinhua Bao

2009-01-01

Conclusions: Human eyes have systematical higher order aberrations in population, and factors that cause bilateral symmetry of wavefront aberrations between the right and left eyes made important contribution to the systematical aberrations.

A scalable multi-resolution spatio-temporal model for brain activation and connectivity in fMRI data

KAUST Repository

Castruccio, Stefano

2018-01-23

Functional Magnetic Resonance Imaging (fMRI) is a primary modality for studying brain activity. Modeling spatial dependence of imaging data at different spatial scales is one of the main challenges of contemporary neuroimaging, and it could allow for accurate testing for significance in neural activity. The high dimensionality of this type of data (on the order of hundreds of thousands of voxels) poses serious modeling challenges and considerable computational constraints. For the sake of feasibility, standard models typically reduce dimensionality by modeling covariance among regions of interest (ROIs)—coarser or larger spatial units—rather than among voxels. However, ignoring spatial dependence at different scales could drastically reduce our ability to detect activation patterns in the brain and hence produce misleading results. We introduce a multi-resolution spatio-temporal model and a computationally efficient methodology to estimate cognitive control related activation and whole-brain connectivity. The proposed model allows for testing voxel-specific activation while accounting for non-stationary local spatial dependence within anatomically defined ROIs, as well as regional dependence (between-ROIs). The model is used in a motor-task fMRI study to investigate brain activation and connectivity patterns aimed at identifying associations between these patterns and regaining motor functionality following a stroke.

Monitoring the Spatiotemporal Activities of miRNAs in Small Animal Models Using Molecular Imaging Modalities

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Patrick Baril

2015-03-01

Full Text Available MicroRNAs (miRNAs are a class of small non-coding RNAs that regulate gene expression by binding mRNA targets via sequence complementary inducing translational repression and/or mRNA degradation. A current challenge in the field of miRNA biology is to understand the functionality of miRNAs under physiopathological conditions. Recent evidence indicates that miRNA expression is more complex than simple regulation at the transcriptional level. MiRNAs undergo complex post-transcriptional regulations such miRNA processing, editing, accumulation and re-cycling within P-bodies. They are dynamically regulated and have a well-orchestrated spatiotemporal localization pattern. Real-time and spatio-temporal analyses of miRNA expression are difficult to evaluate and often underestimated. Therefore, important information connecting miRNA expression and function can be lost. Conventional miRNA profiling methods such as Northern blot, real-time PCR, microarray, in situ hybridization and deep sequencing continue to contribute to our knowledge of miRNA biology. However, these methods can seldom shed light on the spatiotemporal organization and function of miRNAs in real-time. Non-invasive molecular imaging methods have the potential to address these issues and are thus attracting increasing attention. This paper reviews the state-of-the-art of methods used to detect miRNAs and discusses their contribution in the emerging field of miRNA biology and therapy.

Monitoring the spatiotemporal activities of miRNAs in small animal models using molecular imaging modalities.

Science.gov (United States)

Baril, Patrick; Ezzine, Safia; Pichon, Chantal

2015-03-04

MicroRNAs (miRNAs) are a class of small non-coding RNAs that regulate gene expression by binding mRNA targets via sequence complementary inducing translational repression and/or mRNA degradation. A current challenge in the field of miRNA biology is to understand the functionality of miRNAs under physiopathological conditions. Recent evidence indicates that miRNA expression is more complex than simple regulation at the transcriptional level. MiRNAs undergo complex post-transcriptional regulations such miRNA processing, editing, accumulation and re-cycling within P-bodies. They are dynamically regulated and have a well-orchestrated spatiotemporal localization pattern. Real-time and spatio-temporal analyses of miRNA expression are difficult to evaluate and often underestimated. Therefore, important information connecting miRNA expression and function can be lost. Conventional miRNA profiling methods such as Northern blot, real-time PCR, microarray, in situ hybridization and deep sequencing continue to contribute to our knowledge of miRNA biology. However, these methods can seldom shed light on the spatiotemporal organization and function of miRNAs in real-time. Non-invasive molecular imaging methods have the potential to address these issues and are thus attracting increasing attention. This paper reviews the state-of-the-art of methods used to detect miRNAs and discusses their contribution in the emerging field of miRNA biology and therapy.

Different Aberrant Mentalizing Networks in Males and Females with Autism Spectrum Disorders: Evidence from Resting-State Functional Magnetic Resonance Imaging

Science.gov (United States)

Yang, Jie; Lee, Jonathan

2018-01-01

Previous studies have found that individuals with autism spectrum disorders show impairments in mentalizing processes and aberrant brain activity compared with typically developing participants. However, the findings are mainly from male participants and the aberrant effects in autism spectrum disorder females and sex differences are still…

Aberrant activation of NF-κB signaling in mammary epithelium leads to abnormal growth and ductal carcinoma in situ

International Nuclear Information System (INIS)

Barham, Whitney; Chen, Lianyi; Tikhomirov, Oleg; Onishko, Halina; Gleaves, Linda; Stricker, Thomas P.; Blackwell, Timothy S.; Yull, Fiona E.

2015-01-01

Approximately 1 in 5 women diagnosed with breast cancer are considered to have in situ disease, most often termed ductal carcinoma in situ (DCIS). Though recognized as a risk factor for the development of more invasive cancer, it remains unclear what factors contribute to DCIS development. It has been shown that inflammation contributes to the progression of a variety of tumor types, and nuclear factor kappa B (NF-κB) is recognized as a master-regulator of inflammatory signaling. However, the contributions of NF-κB signaling to tumor initiation are less well understood. Aberrant up-regulation of NF-κB activity, either systemically or locally within the breast, could occur due to a variety of commonly experienced stimuli such as acute infection, obesity, or psychological stress. In this study, we seek to determine if activation of NF-κB in mammary epithelium could play a role in the formation of hyperplastic ductal lesions. Our studies utilize a doxycycline-inducible transgenic mouse model in which constitutively active IKKβ is expressed specifically in mammary epithelium. All previously published models of NF-κB modulation in the virgin mammary gland have been constitutive models, with transgene or knock-out present throughout the life and development of the animal. For the first time, we will induce activation at later time points after normal ducts have formed, thus being able to determine if NF-κB activation can promote pre-malignant changes in previously normal mammary epithelium. We found that even a short pulse of NF-κB activation could induce profound remodeling of mammary ductal structures. Short-term activation created hyperproliferative, enlarged ducts with filled lumens. Increased expression of inflammatory markers was concurrent with the down-regulation of hormone receptors and markers of epithelial differentiation. Furthermore, the oncoprotein mucin 1, known to be up-regulated in human and mouse DCIS, was over-expressed and mislocalized in the

HOIP Deficiency Causes Embryonic Lethality by Aberrant TNFR1-Mediated Endothelial Cell Death

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Nieves Peltzer

2014-10-01

Full Text Available Summary: Linear ubiquitination is crucial for innate and adaptive immunity. The linear ubiquitin chain assembly complex (LUBAC, consisting of HOIL-1, HOIP, and SHARPIN, is the only known ubiquitin ligase that generates linear ubiquitin linkages. HOIP is the catalytically active LUBAC component. Here, we show that both constitutive and Tie2-Cre-driven HOIP deletion lead to aberrant endothelial cell death, resulting in defective vascularization and embryonic lethality at midgestation. Ablation of tumor necrosis factor receptor 1 (TNFR1 prevents cell death, vascularization defects, and death at midgestation. HOIP-deficient cells are more sensitive to death induction by both tumor necrosis factor (TNF and lymphotoxin-α (LT-α, and aberrant complex-II formation is responsible for sensitization to TNFR1-mediated cell death in the absence of HOIP. Finally, we show that HOIP’s catalytic activity is necessary for preventing TNF-induced cell death. Hence, LUBAC and its linear-ubiquitin-forming activity are required for maintaining vascular integrity during embryogenesis by preventing TNFR1-mediated endothelial cell death. : HOIP is the main catalytic subunit of the linear ubiquitin chain assembly complex (LUBAC, a crucial regulator of TNF and other immune signaling pathways. Peltzer et al. find that HOIP deficiency results in embryonic lethality at midgestation due to endothelial cell death mediated by TNFR1. Aberrant formation of a TNF-mediated cell-death-inducing complex in HOIP-deficient (but not -proficient cells underlies the phenotype, with the catalytic activity of HOIP required for the control of cell death in response to TNF.

Analysis of the 'dilemma effect' in fifth-order deflection aberration

International Nuclear Information System (INIS)

Zhang Xiaobing; Yin Hanchun; Lei Wei; Xue Kunxing; Tong Linsu

1999-01-01

In this paper, the coma of the fifth-order aberration at a large deflection angle has been analyzed by using multipole field theory. The dilemma effect exists in the comas of fifth-order aberration. The dilemma effect, whose value D r is constant and independent of the 10-pole field, is the linear combination of coma aberrations. The coma of the fifth-order aberration is corrected by adjusting the 10-pole field distribution when D r is zero or small. The factors that influence the dilemma effect have been calculated and analyzed

Chromatic aberrations of two-electrode transaxial mirrors

International Nuclear Information System (INIS)

Bejzina, L.G.; Karetskaya, S.P.

1991-01-01

Second order chromatic aberrations of electrostatic two-electrode transaxial mirrors in case the beam axial trajectory of charged particles is curvilinear are considered. Interrelations between coefficients of linear and angular chromatic aberrations are determined. Values of these coefficients for concave and convex transaxial mirrors with plane electrodes in dependence on potential ratio on electrodes by different onnular clearance radii are presented

Spatiotemporal exploratory models for broad-scale survey data.

Science.gov (United States)

Fink, Daniel; Hochachka, Wesley M; Zuckerberg, Benjamin; Winkler, David W; Shaby, Ben; Munson, M Arthur; Hooker, Giles; Riedewald, Mirek; Sheldon, Daniel; Kelling, Steve

2010-12-01

The distributions of animal populations change and evolve through time. Migratory species exploit different habitats at different times of the year. Biotic and abiotic features that determine where a species lives vary due to natural and anthropogenic factors. This spatiotemporal variation needs to be accounted for in any modeling of species' distributions. In this paper we introduce a semiparametric model that provides a flexible framework for analyzing dynamic patterns of species occurrence and abundance from broad-scale survey data. The spatiotemporal exploratory model (STEM) adds essential spatiotemporal structure to existing techniques for developing species distribution models through a simple parametric structure without requiring a detailed understanding of the underlying dynamic processes. STEMs use a multi-scale strategy to differentiate between local and global-scale spatiotemporal structure. A user-specified species distribution model accounts for spatial and temporal patterning at the local level. These local patterns are then allowed to "scale up" via ensemble averaging to larger scales. This makes STEMs especially well suited for exploring distributional dynamics arising from a variety of processes. Using data from eBird, an online citizen science bird-monitoring project, we demonstrate that monthly changes in distribution of a migratory species, the Tree Swallow (Tachycineta bicolor), can be more accurately described with a STEM than a conventional bagged decision tree model in which spatiotemporal structure has not been imposed. We also demonstrate that there is no loss of model predictive power when a STEM is used to describe a spatiotemporal distribution with very little spatiotemporal variation; the distribution of a nonmigratory species, the Northern Cardinal (Cardinalis cardinalis).

Subjective face recognition difficulties, aberrant sensibility, sleeping disturbances and aberrant eating habits in families with Asperger syndrome

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Källman Tiia

2005-04-01

Full Text Available Abstract Background The present study was undertaken in order to determine whether a set of clinical features, which are not included in the DSM-IV or ICD-10 for Asperger Syndrome (AS, are associated with AS in particular or whether they are merely a familial trait that is not related to the diagnosis. Methods Ten large families, a total of 138 persons, of whom 58 individuals fulfilled the diagnostic criteria for AS and another 56 did not to fulfill these criteria, were studied using a structured interview focusing on the possible presence of face recognition difficulties, aberrant sensibility and eating habits and sleeping disturbances. Results The prevalence for face recognition difficulties was 46.6% in individuals with AS compared with 10.7% in the control group. The corresponding figures for subjectively reported presence of aberrant sensibilities were 91.4% and 46.6%, for sleeping disturbances 48.3% and 23.2% and for aberrant eating habits 60.3% and 14.3%, respectively. Conclusion An aberrant processing of sensory information appears to be a common feature in AS. The impact of these and other clinical features that are not incorporated in the ICD-10 and DSM-IV on our understanding of AS may hitherto have been underestimated. These associated clinical traits may well be reflected by the behavioural characteristics of these individuals.

Resting-state hemodynamics are spatiotemporally coupled to synchronized and symmetric neural activity in excitatory neurons

Science.gov (United States)

Ma, Ying; Shaik, Mohammed A.; Kozberg, Mariel G.; Portes, Jacob P.; Timerman, Dmitriy

2016-01-01

Brain hemodynamics serve as a proxy for neural activity in a range of noninvasive neuroimaging techniques including functional magnetic resonance imaging (fMRI). In resting-state fMRI, hemodynamic fluctuations have been found to exhibit patterns of bilateral synchrony, with correlated regions inferred to have functional connectivity. However, the relationship between resting-state hemodynamics and underlying neural activity has not been well established, making the neural underpinnings of functional connectivity networks unclear. In this study, neural activity and hemodynamics were recorded simultaneously over the bilateral cortex of awake and anesthetized Thy1-GCaMP mice using wide-field optical mapping. Neural activity was visualized via selective expression of the calcium-sensitive fluorophore GCaMP in layer 2/3 and 5 excitatory neurons. Characteristic patterns of resting-state hemodynamics were accompanied by more rapidly changing bilateral patterns of resting-state neural activity. Spatiotemporal hemodynamics could be modeled by convolving this neural activity with hemodynamic response functions derived through both deconvolution and gamma-variate fitting. Simultaneous imaging and electrophysiology confirmed that Thy1-GCaMP signals are well-predicted by multiunit activity. Neurovascular coupling between resting-state neural activity and hemodynamics was robust and fast in awake animals, whereas coupling in urethane-anesthetized animals was slower, and in some cases included lower-frequency (resting-state hemodynamics in the awake and anesthetized brain are coupled to underlying patterns of excitatory neural activity. The patterns of bilaterally-symmetric spontaneous neural activity revealed by wide-field Thy1-GCaMP imaging may depict the neural foundation of functional connectivity networks detected in resting-state fMRI. PMID:27974609

Brown's TRANSPORT up to third order aberration by artificial intelligence

International Nuclear Information System (INIS)

Xia Jiawen; Xie Xi; Qiao Qingwen

1991-01-01

Brown's TRANSPORT is a first and second order matrix multiplication computer program intended for the design of accelerator beam transport systems, neglecting the third order aberration. Recently a new method was developed to derive analytically any order aberration coefficients of general charged particle optic system, applicable to any practical systems, such as accelerators, electron microscopes, lithographs, etc., including those unknown systems yet to be invented. An artificial intelligence program in Turbo Prolog was implemented on IBM-PC 286 or 386 machine to generate automatically the analytical expression of any order aberration coefficients of general charged particle optic system. Based on this new method and technique, Brown's TRANSPORT is extended beyond the second order aberration effects by artificial intelligence, outputing automatically all the analytical expressions up to the third order aberration coefficients

Brown's transport up to third order aberration by artificial intelligence

International Nuclear Information System (INIS)

Xia Jiawen; Xie Xi; Qiao Qingwen

1992-01-01

Brown's TRANSPORT is a first and second order matrix multiplication computer program intended for the design of accelerator beam transport systems, neglecting the third order aberration. Recently a new method was developed to derive analytically any order aberration coefficients of general charged particle optic system, applicable to any practical systems, such as accelerators, electron microscopes, lithographs, including those unknown systems yet to be invented. An artificial intelligence program in Turbo Prolog was implemented on IBM-PC 286 or 386 machine to generate automatically the analytical expression of any order aberration coefficients of general charged particle optic system. Based on this new method and technique, Brown's TRANSPORT is extended beyond the second order aberration effect by artificial intelligence, outputting automatically all the analytical expressions up to the third order aberration coefficients

Chromosomal aberrations in subjects exposed to ionizing radiation

International Nuclear Information System (INIS)

Jovicic, D.; Milacic, S.; Kovacevic, R.; Tanaskovic, I.

2006-01-01

Occupational exposure is particularly delicate because of chronic exposure to low doses of ionizing radiation and its cumulative effect, where it is important to consider the biological response of body to given conditions of exposure. The objective of this study was the observation of the recovery of the DNA damages in subjects working in the radiation area in two different intervals.Group I, consisting of 30 subjects, was exposed to ionizing radiation and unstable chromosomal aberrations were identified. Group II included the same, re-examined subjects (30) 9 months later. It was verified that 5 (16.67%) subjects still had unstable chromosomal aberrations, although they had been excluded from radiation area Controls groups (C) consisted of 64 subjects that were not exposed to mutagenic agents.The comparison of the control group with the two studied groups revealed the reduction of the unstable aberrations (p<0.05). The total effective doses, which increased with the years spent in radiation area, reflected the yield of chromosomal aberrations. The presence of chromosomal aberrations in some subjects, after the exclusion from the ionising radiation exposure, suggests that the time needed for the recovery of the DNA damages is different, which indicates the individual differences in radiosensitivity as well as different of the reparatory cellular response. (author)

Spatio-temporal networks: reachability, centrality and robustness.

Science.gov (United States)

Williams, Matthew J; Musolesi, Mirco

2016-06-01

Recent advances in spatial and temporal networks have enabled researchers to more-accurately describe many real-world systems such as urban transport networks. In this paper, we study the response of real-world spatio-temporal networks to random error and systematic attack, taking a unified view of their spatial and temporal performance. We propose a model of spatio-temporal paths in time-varying spatially embedded networks which captures the property that, as in many real-world systems, interaction between nodes is non-instantaneous and governed by the space in which they are embedded. Through numerical experiments on three real-world urban transport systems, we study the effect of node failure on a network's topological, temporal and spatial structure. We also demonstrate the broader applicability of this framework to three other classes of network. To identify weaknesses specific to the behaviour of a spatio-temporal system, we introduce centrality measures that evaluate the importance of a node as a structural bridge and its role in supporting spatio-temporally efficient flows through the network. This exposes the complex nature of fragility in a spatio-temporal system, showing that there is a variety of failure modes when a network is subject to systematic attacks.

Spectral estimation for characterization of acoustic aberration.

Science.gov (United States)

Varslot, Trond; Angelsen, Bjørn; Waag, Robert C

2004-07-01

Spectral estimation based on acoustic backscatter from a motionless stochastic medium is described for characterization of aberration in ultrasonic imaging. The underlying assumptions for the estimation are: The correlation length of the medium is short compared to the length of the transmitted acoustic pulse, an isoplanatic region of sufficient size exists around the focal point, and the backscatter can be modeled as an ergodic stochastic process. The motivation for this work is ultrasonic imaging with aberration correction. Measurements were performed using a two-dimensional array system with 80 x 80 transducer elements and an element pitch of 0.6 mm. The f number for the measurements was 1.2 and the center frequency was 3.0 MHz with a 53% bandwidth. Relative phase of aberration was extracted from estimated cross spectra using a robust least-mean-square-error method based on an orthogonal expansion of the phase differences of neighboring wave forms as a function of frequency. Estimates of cross-spectrum phase from measurements of random scattering through a tissue-mimicking aberrator have confidence bands approximately +/- 5 degrees wide. Both phase and magnitude are in good agreement with a reference characterization obtained from a point scatterer.

Analyzing Spatiotemporal Anomalies through Interactive Visualization

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Tao Zhang

2014-06-01

Full Text Available As we move into the big data era, data grows not just in size, but also in complexity, containing a rich set of attributes, including location and time information, such as data from mobile devices (e.g., smart phones, natural disasters (e.g., earthquake and hurricane, epidemic spread, etc. We are motivated by the rising challenge and build a visualization tool for exploring generic spatiotemporal data, i.e., records containing time location information and numeric attribute values. Since the values often evolve over time and across geographic regions, we are particularly interested in detecting and analyzing the anomalous changes over time/space. Our analytic tool is based on geographic information system and is combined with spatiotemporal data mining algorithms, as well as various data visualization techniques, such as anomaly grids and anomaly bars superimposed on the map. We study how effective the tool may guide users to find potential anomalies through demonstrating and evaluating over publicly available spatiotemporal datasets. The tool for spatiotemporal anomaly analysis and visualization is useful in many domains, such as security investigation and monitoring, situation awareness, etc.

Biodosimetry for medical diagnostic X-ray workers using stable chromosome aberration

International Nuclear Information System (INIS)

Wang Zhiquan; Liu Xuping; Li Jin

1996-01-01

The stable chromosome aberrations of medical diagnostic X-ray workers were analyzed using G-banding and their accumulative doses were evaluated. The results showed that the frequencies of reciprocal translocation, stable aberration and total aberration among the 4417 metaphase spread from 44 cases of medical diagnostic X-ray workers were distinctly higher than control values (P<0.05∼0.005). The stable aberration predominated strikingly in total aberration and reciprocal translocation was 57% in the stable aberrations. The medical diagnostic X-ray workers were divided into 3 groups according to calendar year of entry. The data showed that the frequencies of total aberration, stable aberration and reciprocal translocation increased with working years, especially in two groups who started working before 1970, there are statistically significant differences between the calendar year of entry before 1960 and 1960∼1969 in X-ray workers and control group. According to the equation recommended by Straume, linear coefficient (α) in linear quadratic model recommended by Schmid and the transformation coefficient by Lucas, the accumulative doses calculated are 0.58, 0.37 and 0.07 Gy for calendar year of entry before 1960, 1960∼1969 and after 1970 in X-ray workers, respectively

Higher order monochromatic aberrations of the human infant eye

OpenAIRE

Wang, Jingyun; Candy, T. Rowan

2005-01-01

The monochromatic optical aberrations of the eye degrade retinal image quality. Any significant aberrations during postnatal development could contribute to infants’ immature visual performance and provide signals for the control of eye growth. Aberrations of human infant eyes from 5 to 7 weeks old were compared with those of adult subjects using a model of an adultlike infant eye that accounted for differences in both eye and pupil size. Data were collected using the COAS Shack-Hartmann wave...

Chromosomal aberrations in children exposed to diagnostic x-rays

International Nuclear Information System (INIS)

Nordenson, I.; Beckman, G.; Beckman, L.; Lemperg, R.

1980-01-01

Among children who have received high x-ray doses congenital dislocation of the hip joint is the predominating diagnosis. In a series of 9 children who had received high x-ray doses (8 with luxation of the hip joint and one with achondroplasia) a significant increase of chromosomal aberrations was found. The increase concerned mainly chromosome type aberrations. The shorter the time since the last x-ray investigation the higher was the frequency of chromosome type aberrations. (author)

Unsupervised Learning of Spatiotemporal Features by Video Completion

OpenAIRE

Nallabolu, Adithya Reddy

2017-01-01

In this work, we present an unsupervised representation learning approach for learning rich spatiotemporal features from videos without the supervision from semantic labels. We propose to learn the spatiotemporal features by training a 3D convolutional neural network (CNN) using video completion as a surrogate task. Using a large collection of unlabeled videos, we train the CNN to predict the missing pixels of a spatiotemporal hole given the remaining parts of the video through minimizing per...

Comparison of Spatiotemporal Fusion Models: A Review

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Bin Chen

2015-02-01

Full Text Available Simultaneously capturing spatial and temporal dynamics is always a challenge for the remote sensing community. Spatiotemporal fusion has gained wide interest in various applications for its superiority in integrating both fine spatial resolution and frequent temporal coverage. Though many advances have been made in spatiotemporal fusion model development and applications in the past decade, a unified comparison among existing fusion models is still limited. In this research, we classify the models into three categories: transformation-based, reconstruction-based, and learning-based models. The objective of this study is to (i compare four fusion models (STARFM, ESTARFM, ISTAFM, and SPSTFM under a one Landsat-MODIS (L-M pair prediction mode and two L-M pair prediction mode using time-series datasets from the Coleambally irrigation area and Poyang Lake wetland; (ii quantitatively assess prediction accuracy considering spatiotemporal comparability, landscape heterogeneity, and model parameter selection; and (iii discuss the advantages and disadvantages of the three categories of spatiotemporal fusion models.

Wnt/β-catenin signalling pathway mediated aberrant hippocampal neurogenesis in kainic acid-induced epilepsy.

Science.gov (United States)

Qu, Zhengyi; Su, Fang; Qi, Xueting; Sun, Jianbo; Wang, Hongcai; Qiao, Zhenkui; Zhao, Hong; Zhu, Yulan

2017-10-01

Temporal lobe epilepsy is a chronic disorder of nerve system, mainly characterized by hippocampal sclerosis with massive neuronal loss and severe gliosis. Aberrant neurogenesis has been shown in the epileptogenesis process of temporal lobe epilepsy. However, the molecular mechanisms underlying aberrant neurogenesis remain unclear. The roles of Wnt signalling cascade have been well established in neurogenesis during multiple aspects. Here, we used kainic acid-induced rat epilepsy model to investigate whether Wnt/β-catenin signalling pathway is involved in the aberrant neurogenesis in temporal lobe epilepsy. Immunostaining and western blotting results showed that the expression levels of β-catenin, Wnt3a, and cyclin D1, the key regulators in Wnt signalling pathway, were up-regulated during acute epilepsy induced by the injection of kainic acids, indicating that Wnt signalling pathway was activated in kainic acid-induced temporal lobe epilepsy. Moreover, BrdU labelling results showed that blockade of the Wnt signalling by knocking down β-catenin attenuated aberrant neurogenesis induced by kainic acids injection. Altogether, Wnt/β-catenin signalling pathway mediated hippocampal neurogenesis during epilepsy, which might provide new strategies for clinical treatment of temporal lobe epilepsy. Temporal lobe epilepsy is a chronic disorder of nerve system, mainly characterized by hippocampal sclerosis. Aberrant neurogenesis has been shown to involve in the epileptogenesis process of temporal lobe epilepsy. In the present study, we discovered that Wnt3a/β-catenin signalling pathway serves as a link between aberrant neurogenesis and underlying remodelling in the hippocampus, leading to temporal lobe epilepsy, which might provide new strategies for clinical treatment of temporal lobe epilepsy. Copyright © 2017 John Wiley & Sons, Ltd.

Chromosomal aberration in peripheral lymphocytes and doses to the active bone marrow in radiotherapy of prostate cancer

International Nuclear Information System (INIS)

Gershkevitsh, E.; Trott, K.R.

2002-01-01

Purpose: Radiotherapy plays an important role in the management of prostate cancer. Epidemiological data indicate a small but significant risk of radiation-induced leukemia after radiotherapy which might be related to the high mean bone marrow dose associated with radiotherapy of prostate cancer. The purpose of the study was to investigate the relation between the mean bone marrow dose and unstable chromosome aberrations in peripheral blood lymphocytes in patients undergoing conformal radiotherapy for prostate cancer as a possible indicator of risk. Endometrial cancer patients were also included for comparison. Patients and Methods: Nine patients, six with prostate cancer (60-73 years old) and three with endometrial cancer (61-81 years old) treated with radiotherapy were included in the study. The non-bony spaces inside the pelvic bones were outlined on every CT slice using the treatment planning system and mean doses to the bone marrow calculated. Blood samples of the patients were obtained at different times before, during and at the end of treatment. Lymphocytes were cultured in the usual way and metaphases scored for dicentric aberrations. Results: 46 samples from nine patients were obtained. The mean number of metaphases analyzed per sample was 180 with a range from 52 to 435. The mean bone marrow doses for prostate cancer patients ranged from 2.8 to 4.2 Gy and for endometrial cancer patients from 12.8 to 14.8 Gy. The aberration yield increased with the planning target volume and the mean bone marrow dose. Conclusion: The yield of dicentric aberrations for prostate cancer patients correlated closely with the mean bone marrow dose albeit the induction of dicentrics occurred in mature T lymphocytes most of which were probably in transit through the irradiated volumes. Therefore, the observed relationship between dicentrics and mean bone marrow doses are indirect. (orig.) [de

In vivo longitudinal chromatic aberration of pseudophakic eyes.

Science.gov (United States)

Siedlecki, Damian; Jóźwik, Agnieszka; Zając, Marek; Hill-Bator, Aneta; Turno-Kręcicka, Anna

2014-02-01

To present the results of longitudinal chromatic aberration measurements on two groups of pseudophakic eyes in comparison to healthy eyes. The longitudinal chromatic aberration of the eye, defined as chromatic difference of refraction with disabled accommodation, was measured with the use of a visual refractometer with a custom-designed target illuminator consisting of a narrow-band RGB diode (blue λb = 470 ± 15 nm; green λg = 525 ± 18 nm; red λr = 660 ± 10 nm). The measurements were performed on nine eyes implanted with AcrySof IQ SN60WF, 14 eyes implanted with AcrySof SA60AT, and 10 phakic eyes under cycloplegia. The mean values of the longitudinal chromatic aberration between 470 and 660 nm for the control group was 1.12 ± 0.14 D. For SA60AT group, it was 1.45 ± 0.42 D whereas for SN60WF it was 1.17 ± 0.52 D. The statistical test showed significant difference between SA60AT and the control group (p chromatic aberration in vivo can be easily and reliably estimated with an adapted visual refractometer. The two groups of pseudophakic eyes measured in this study showed different values of chromatic aberration. Its magnitude for SA60AT group was significantly larger than for the control group whereas for SN60WF the difference was not significant. The optical material used for intraocular lens design may have significant influence on the magnitude of the chromatic aberration of the pseudophakic eye, and therefore on its optical and visual performance in polychromatic light.

Simultaneous spatio-temporal focusing for tissue manipulation

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Squier J.

2013-11-01

Full Text Available Simultaneous spatiotemporal focusing (SSTF is applied to lens tissue and compared directly with standard femtosecond micromachining of the tissue at the same numerical aperture. Third harmonic generation imaging is used for spatio-temporal characterization of the processing conditions obtained with both a standard and SSTF focus.

Cellular origin of prognostic chromosomal aberrations in AML patients

DEFF Research Database (Denmark)

Mora-Jensen, H.; Jendholm, J.; Rapin, N.

2015-01-01

chromosomal structural rearrangements and single nucleotide variants (SNVs). Conventional AML diagnostics and recent seminal next-generation sequencing (NGS) studies have identified more than 200 recurrent genetic aberrations presenting in various combinations in individual patients. Significantly, many...... of these aberrations occur in normal hematopoietic stem and progenitor cells (HSCs/HPCs) before definitive leukemic transformation through additional acquisition of a few (that is, mostly 1 or 2) leukemia-promoting driver aberrations. NGS studies on sorted bone marrow (BM) populations of AML patients with a normal...

Structural and numerical chromosome aberration inducers in liver micronucleus test in rats with partial hepatectomy.

Science.gov (United States)

Itoh, Satoru; Hattori, Chiharu; Nagata, Mayumi; Sanbuissho, Atsushi

2012-08-30

The liver micronucleus test is an important method to detect pro-mutagens such as active metabolites not reaching bone marrow due to their short lifespan. We have already reported that dosing of the test compound after partial hepatectomy (PH) is essential to detect genotoxicity of numerical chromosome aberration inducers in mice [Mutat. Res. 632 (2007) 89-98]. In naive animals, the proportion of binucleated cells in rats is less than half of that in mice, which suggests a species difference in the response to chromosome aberration inducers. In the present study, we investigated the responses to structural and numerical chromosome aberration inducers in the rat liver micronucleus test. Two structural chromosome aberretion inducers (diethylnitrosamine and 1,2-dimethylhydrazine) and two numerical chromosome aberration inducers (colchicine and carbendazim) were used in the present study. PH was performed a day before or after the dosing of the test compound in 8-week old male F344 rats and hepatocytes were isolated 4 days after the PH. As a result, diethylnitrosamine and 1,2-dimethylhydrazine, structural chromosome aberration inducers, exhibited significant increase in the incidence of micronucleated hepatocyte (MNH) when given either before and after PH. Colchicine and carbendazim, numerical chromosome aberration inducers, did not result in any toxicologically significant increase in MNH frequency when given before PH, while they exhibited MNH induction when given after PH. It is confirmed that dosing after PH is essential in order to detect genotoxicity of numerical chromosome aberration inducers in rats as well as in mice. Regarding the species difference, a different temporal response to colchicine was identified. Colchicine increased the incidence of MNH 4 days after PH in rats, although such induction in mice was observed 8-10 days after PH. Copyright © 2012 Elsevier B.V. All rights reserved.

Aberration Correction in the Brewer Spectrophotometer

International Nuclear Information System (INIS)

Johnston, J.E.; Kerr, J.B.; McElroy, C.T.; Wardle, D.I.

2000-01-01

The optical design of the Brewer Spectrophotometer has been optimised for measurements in the 300-320 nm wavelength range. An aberration resolution limit that is much less than the 0.6 nm FWHM (full width at half maximum) is achieved by using an Ebert-Fastie spectrometer design, modified by the inclusion tilted lens that optimises performance at 310 nm. The small contribution of the remaining aberration to the measured instrument function is critical to radiometric measurement quality. Ramifications of this design to the development of instrumentation with enhanced scanning abilities are discussed. (author)

Analysis of Relations between Spatiotemporal Movement Regulation and Performance of Discrete Actions Reveals Functionality in Skilled Climbing

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Dominic Orth

2017-10-01

Full Text Available In this review of research on climbing expertise, we focus on different measures of climbing performance, including spatiotemporal measures related to fluency and activity states (i.e., discrete actions, adopted by climbers for achieving overall performance goals of getting to the end of a route efficiently and safely. Currently, a broad range of variables have been reported, however, many of these fail to capture how climbers adapt to a route whilst climbing. We argue that spatiotemporal measures should be considered concurrently with evaluation of activity states (such as reaching or exploring in order gain a more comprehensive picture of how climbers successfully adapt to a route. Spatial and temporal movement measures taken at the hip are a traditional means of assessing efficiency of climbing behaviors. More recently, performatory and exploratory actions of the limbs have been used in combination with spatiotemporal indicators, highlighting the influence of limb states on climbing efficiency and skill transfer. However, only a few studies have attempted to combine spatiotemporal and activity state measures taken during route climbing. This review brings together existing approaches for observing climbing skill at performance outcome (i.e., spatiotemporal assessments and process (i.e., limb activity states levels of analysis. Skill level is associated with a spatially efficient route progression and lower levels of immobility. However, more difficult hold architecture designs require significantly greater mobility and more complex movement patterning to maintain performance. Different forms of functional, or goal-supportive, movement variability, including active recovery and hold exploration, have been implicated as important adaptations to physiological and environmental dynamics that emerge during the act of climbing. Indeed, recently it has also been shown that, when climbing on new routes, efficient exploration can improve the transfer

p-Benzoquinone initiates non-invasive urothelial cancer through aberrant tyrosine phosphorylation of EGFR, MAP kinase activation and cell cycle deregulation: Prevention by vitamin C

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Shinjini Ganguly

Full Text Available According to WHO classification system, non-invasive urothelial carcinoma represents urothelial carcinoma in situ (CIS and dysplasia. Dysplastic urothelium often progresses to CIS that further advances to urothelial carcinoma (UC. The strongest risk factor for UC is cigarette smoking. However, the pathogenesis of cigarette smoke (CS-induced UC is poorly understood. Earlier we had shown that p-benzoquinone (p-BQ, a major toxic quinone derived from p-benzosemiquinone of CS in vivo, is a causative factor for various CS-induced diseases. Here, using a guinea pig model we showed that prolonged treatment with p-BQ led to non-invasive UC, specifically carcinoma in situ (CIS of the renal pelvis and dysplasia in the ureter and bladder. The mechanisms of carcinogenesis were p-BQ-induced oxidative damage and apoptosis that were later suppressed and followed by activation of epidermal growth factor receptor, aberrant phosphorylation of intracellular tyrosine residues, activation of MAP kinase pathway and persistent growth signaling. This was accompanied by deregulation of cell cycle as shown by marked decrease in the expression of p21waf1/cip1 and cyclin D1 proteins as well as hyperphosphorylation of pRb. UC has been characterised by histopathology and immunohistochemistry showing aberrant CK20, increased Ki-67, and marked p53 nuclear immunopositivity with uniformly negative labelling of CD44. Oral supplementation of vitamin C (30 mg/kg body weight/day prevented CIS of the renal pelvis and dysplasia in the ureter and bladder. Since majority of non-invasive UC progresses to invasive cancer with increased risk of mortality, our preclinical study might help to devise effective strategies for early intervention of the disease. Abbreviations: Bax, Bcl-2, CS, DNPH, GAPDH, IARC, p-BQ, p-BSQ, PAHs, PBS, ROS, SDS PAGE, TUNEL, WHO, UC, CIS, EGFR, MAPK, Keywords: p-Benzoquinone, Carcinoma in situ, Dysplasia, Aberrant EGFR activation, Cell cycle deregulation

Dimensions of driving anger and their relationships with aberrant driving.

Science.gov (United States)

Zhang, Tingru; Chan, Alan H S; Zhang, Wei

2015-08-01

The purpose of this study was to investigate the relationship between driving anger and aberrant driving behaviours. An internet-based questionnaire survey was administered to a sample of Chinese drivers, with driving anger measured by a 14-item short Driving Anger Scale (DAS) and the aberrant driving behaviours measured by a 23-item Driver Behaviour Questionnaire (DBQ). The results of Confirmatory Factor Analysis demonstrated that the three-factor model (hostile gesture, arrival-blocking and safety-blocking) of the DAS fitted the driving anger data well. The Exploratory Factor Analysis on DBQ data differentiated four types of aberrant driving, viz. emotional violation, error, deliberate violation and maintaining progress violation. For the anger-aberration relation, it was found that only "arrival-blocking" anger was a significant positive predictor for all four types of aberrant driving behaviours. The "safety-blocking" anger revealed a negative impact on deliberate violations, a finding different from previously established positive anger-aberration relation. These results suggest that drivers with different patterns of driving anger would show different behavioural tendencies and as a result intervention strategies may be differentially effective for drivers of different profiles. Copyright © 2015 Elsevier Ltd. All rights reserved.

Ocular wavefront aberration and refractive error in pre-school children

Science.gov (United States)

Thapa, Damber; Fleck, Andre; Lakshminarayanan, Vasudevan; Bobier, William R.

2011-11-01

Hartmann-Shack images taken from an archived collection of SureSight refractive measurements of pre-school children in Oxford County, Ontario, Canada were retrieved and re-analyzed. Higher-order aberrations were calculated over the age range of 3 to 6 years. These higher-order aberrations were compared with respect to magnitudes of ametropia. Subjects were classified as emmetropic (range -0.5 to + 0.5D), low hyperopic (+ 0.5 to +2D) and high hyperopic (+2D or more) based upon the resulting spherical equivalent. Higher-order aberrations were found to increase with higher levels of hyperopia (p < 0.01). The strongest effect was for children showing more than +2.00D of hyperopia. The correlation coefficients were small in all of the higher-order aberrations; however, they were significant (p < 0.01). These analyses indicate a weak association between refractive error and higher-order aberrations in pre-school children.

Prospects for electron beam aberration correction using sculpted phase masks

Energy Technology Data Exchange (ETDEWEB)

Shiloh, Roy, E-mail: royshilo@post.tau.ac.il; Remez, Roei; Arie, Ady

2016-04-15

Technological advances in fabrication methods allowed the microscopy community to take incremental steps towards perfecting the electron microscope, and magnetic lens design in particular. Still, state of the art aberration-corrected microscopes are yet 20–30 times shy of the theoretical electron diffraction limit. Moreover, these microscopes consume significant physical space and are very expensive. Here, we show how a thin, sculpted membrane is used as a phase-mask to induce specific aberrations into an electron beam probe in a standard high resolution TEM. In particular, we experimentally demonstrate beam splitting, two-fold astigmatism, three-fold astigmatism, and spherical aberration. - Highlights: • Thin membranes can be used as aberration correctors in electron columns. • We demonstrate tilt, twofold-, threefold-astigmatism, and spherical aberrations. • Experimental and physical-optics simulation results are in good agreement. • Advantages in cost, size, nonmagnetism, and nearly-arbitrary correction.

Comparison of wavefront aberrations under cycloplegic, scotopic and photopic conditions using WaveScan

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Rong Fan

2012-04-01

Full Text Available PURPOSE: To evaluate the differences of wavefront aberrations under cycloplegic, scotopic and photopic conditions. METHODS: A total of 174 eyes of 105 patients were measured using the wavefront sensor (WaveScan® 3.62 under different pupil conditions: cycloplegic 8.58 ± 0.54 mm (6.4 mm - 9.5 mm, scotopic 7.53 ± 0.69 mm (5.7 mm - 9.1 mm and photopic 6.08 ± 1.14 mm (4.1 mm - 8.8 mm. The pupil diameter, standard Zernike coefficients, root mean square of higher-order aberrations and dominant aberrations were compared between cycloplegic and scotopic conditions, and between scotopic and photopic conditions. RESULTS: The pupil diameter was 7.53 ± 0.69 mm under the scotopic condition, which reached the requirement of about 6.5 mm optical zone design in the wavefront-guided surgery and prevented measurement error due to the pupil centroid shift caused by mydriatics. Pharmacological pupil dilation induced increase of standard Zernike coefficients Z3-3, Z4(0 and Z5-5. The higher-order aberrations, third-order aberration, fourth-order aberration, fifth-order aberration, sixth-order aberration, and spherical aberration increased statistically significantly, compared to the scotopic condition (P<0.010. When the scotopic condition shifted to the photopic condition, the standard Zernike coefficients Z4(0, Z4², Z6-4, Z6-2, Z6² decreased and all the higher-order aberrations decreased statistically significantly (P<0.010, demonstrating that accommodative miosis can significantly improve vision under the photopic condition. Under the three conditions, the vertical coma aberration appears the most frequently within the dominant aberrations without significant effect by pupil size variance, and the proportion of spherical aberrations decreased with the decrease of the pupil size. CONCLUSIONS: The wavefront aberrations are significantly different under cycloplegic, scotopic and photopic conditions. Using the wavefront sensor (VISX WaveScan to measure scotopic

Aberrant salience, self-concept clarity, and interview-rated psychotic-like experiences.

Science.gov (United States)

Cicero, David C; Docherty, Anna R; Becker, Theresa M; Martin, Elizabeth A; Kerns, John G

2015-02-01

Many social-cognitive models of psychotic-like symptoms posit a role for self-concept and aberrant salience. Previous work has shown that the interaction between aberrant salience and self-concept clarity is associated with self-reported psychotic-like experiences. In the current research with two structured interviews, the interaction between aberrant salience and self-concept clarity was found to be associated with interview-rated psychotic-like experiences. The interaction was associated with psychotic-like experiences composite scores, delusional ideation, grandiosity, and perceptual anomalies. In all cases, self-concept clarity was negatively associated with psychotic-like experiences at high levels of aberrant salience, but unassociated with psychotic-like experiences at low levels of aberrant salience. The interaction was specific to positive psychotic-like experiences and not present for negative or disorganized ratings. The interaction was not mediated by self-esteem levels. These results provide further evidence that aberrant salience and self-concept clarity play an important role in the generation of psychotic-like experiences.

Recurrent branchial sinus tract with aberrant extension.

Science.gov (United States)

Barret, J P

2004-01-01

Second branchial cysts are the commonest lesions among congenital lateral neck anomalies. Good knowledge of anatomy and embryology are necessary for proper treatment. Surgical treatment involves resection of all branchial remnants, which extend laterally in the neck, medial to the sternocleidomastoid muscle with cranial extension to the pharynx and ipsilateral tonsillar fosa. However, infections and previous surgery can distort anatomy, making the approach to branchial anomalies more difficult. We present a case of a 17-year-old patient who presented with a second branchial tract anomaly with an aberrant extension to the midline and part of the contralateral neck. Previous surgical interventions and chronic infections may have been the primary cause for this aberrant tract. All head and neck surgeons should bear in mind that aberrant presentations may exist when reoperating on chronic branchial cysts fistulas.

Study of radiation-induced chromosomal aberrations

International Nuclear Information System (INIS)

Wolfring, E.

2004-06-01

A method for determining chromosomal aberrations was established for the purpose of examining the relative biological effectiveness (RBE) of photon radiation with respect to mammary epithelium cells. Cells were exposed to 25 kV X-radiation and to 200 kV X-radiation for comparison and the resulting concentrations of chromosomal aberrations were compared. The RBE M value for radiation-induced fragmentation was found to be 4.2 ± 2.4, while the RBE M value for radiation-induced generation of dicentric chromosomes was found to be 0.5 ± 0.5. In addition to the evaluation of chromosomal aberrations the number of cell cycles undergone by the cells was monitored by means of BrDU staining. As expected, the proportion of cells which underwent more than one cell cycle following exposure to 5 Gy was very low in both cases, amounting to 1.9% (25 kV) and 3.2 (200 kV). Non-radiated cells yielded control values of 26.0% and 12.6%, suggesting variations in external conditions from day to day

Visualization and assessment of spatio-temporal covariance properties

KAUST Repository

Huang, Huang

2017-11-23

Spatio-temporal covariances are important for describing the spatio-temporal variability of underlying random fields in geostatistical data. For second-order stationary random fields, there exist subclasses of covariance functions that assume a simpler spatio-temporal dependence structure with separability and full symmetry. However, it is challenging to visualize and assess separability and full symmetry from spatio-temporal observations. In this work, we propose a functional data analysis approach that constructs test functions using the cross-covariances from time series observed at each pair of spatial locations. These test functions of temporal lags summarize the properties of separability or symmetry for the given spatial pairs. We use functional boxplots to visualize the functional median and the variability of the test functions, where the extent of departure from zero at all temporal lags indicates the degree of non-separability or asymmetry. We also develop a rank-based nonparametric testing procedure for assessing the significance of the non-separability or asymmetry. Essentially, the proposed methods only require the analysis of temporal covariance functions. Thus, a major advantage over existing approaches is that there is no need to estimate any covariance matrix for selected spatio-temporal lags. The performances of the proposed methods are examined by simulations with various commonly used spatio-temporal covariance models. To illustrate our methods in practical applications, we apply it to real datasets, including weather station data and climate model outputs.

Sextupole system for the correction of spherical aberration

Science.gov (United States)

Crewe, A.V.; Kopf, D.A.

In an electron beam device in which an electron beam is developed and then focused by a lens to a particular spot, there is provided a means for eliminating spherical aberration. A sextupole electromagnetic lens is positioned between two focusing lenses. The interaction of the sextupole with the beam compensates for spherical aberration. (GHT)

Brillouin micro-spectroscopy through aberrations via sensorless adaptive optics

Science.gov (United States)

Edrei, Eitan; Scarcelli, Giuliano

2018-04-01

Brillouin spectroscopy is a powerful optical technique for non-contact viscoelastic characterizations which has recently found applications in three-dimensional mapping of biological samples. Brillouin spectroscopy performances are rapidly degraded by optical aberrations and have therefore been limited to homogenous transparent samples. In this work, we developed an adaptive optics (AO) configuration designed for Brillouin scattering spectroscopy to engineer the incident wavefront and correct for aberrations. Our configuration does not require direct wavefront sensing and the injection of a "guide-star"; hence, it can be implemented without the need for sample pre-treatment. We used our AO-Brillouin spectrometer in aberrated phantoms and biological samples and obtained improved precision and resolution of Brillouin spectral analysis; we demonstrated 2.5-fold enhancement in Brillouin signal strength and 1.4-fold improvement in axial resolution because of the correction of optical aberrations.

Theoretical estimates of spherical and chromatic aberration in photoemission electron microscopy

Energy Technology Data Exchange (ETDEWEB)

Fitzgerald, J.P.S., E-mail: fit@pdx.edu; Word, R.C.; Könenkamp, R.

2016-01-15

We present theoretical estimates of the mean coefficients of spherical and chromatic aberration for low energy photoemission electron microscopy (PEEM). Using simple analytic models, we find that the aberration coefficients depend primarily on the difference between the photon energy and the photoemission threshold, as expected. However, the shape of the photoelectron spectral distribution impacts the coefficients by up to 30%. These estimates should allow more precise correction of aberration in PEEM in experimental situations where the aberration coefficients and precise electron energy distribution cannot be readily measured. - Highlights: • Spherical and chromatic aberration coefficients of the accelerating field in PEEM. • Compact, analytic expressions for coefficients depending on two emission parameters. • Effect of an aperture stop on the distribution is also considered.

A model of distributed phase aberration for deblurring phase estimated from scattering.

Science.gov (United States)

Tillett, Jason C; Astheimer, Jeffrey P; Waag, Robert C

2010-01-01

Correction of aberration in ultrasound imaging uses the response of a point reflector or its equivalent to characterize the aberration. Because a point reflector is usually unavailable, its equivalent is obtained using statistical methods, such as processing reflections from multiple focal regions in a random medium. However, the validity of methods that use reflections from multiple points is limited to isoplanatic patches for which the aberration is essentially the same. In this study, aberration is modeled by an offset phase screen to relax the isoplanatic restriction. Methods are developed to determine the depth and phase of the screen and to use the model for compensation of aberration as the beam is steered. Use of the model to enhance the performance of the noted statistical estimation procedure is also described. Experimental results obtained with tissue-mimicking phantoms that implement different models and produce different amounts of aberration are presented to show the efficacy of these methods. The improvement in b-scan resolution realized with the model is illustrated. The results show that the isoplanatic patch assumption for estimation of aberration can be relaxed and that propagation-path characteristics and aberration estimation are closely related.

Mutations and chromosomal aberrations

International Nuclear Information System (INIS)

Kihlman, B.A.

1977-01-01

The genetic changes of mutations and chromosomal aberrations are discussed. The consequences of both depend not only on the type of genetic change produced but also on the type of cell that is affected and on the development stage of the organism. (C.F.)

Effects of residual aberrations explored on single-walled carbon nanotubes

International Nuclear Information System (INIS)

Biskupek, Johannes; Hartel, Peter; Haider, Maximilian; Kaiser, Ute

2012-01-01

The effects of geometric residual aberrations such as coma B 2 and two-fold astigmatism A 1 on the contrast in aberration corrected high resolution transmission electron microscopy (HRTEM) images are investigated on single-walled carbon nanotubes (SWNT). The individual aberrations are adjusted and set up manually using an imaging C S -corrector. We demonstrate how coma B 2 can be recognized by an experienced user directly in the image and how it blurs the contrast. Even with uncorrected (resolution limiting) spherical aberration C S the coma B 2 has to be considered and must be minimized. Limits for a tolerable coma are given. The experiments are confirmed by image simulations. -- Highlights: ► Individual effects of residual aberrations such as B 2 , A 1 , and C S are demonstrated. ► Experimental HRTEM and simulated images of carbon nanotubes are compared. ► A detection limit of 50 nm B 2 in a single HRTEM image is determined.

Correlation between Post-LASIK Starburst Symptom and Ocular Wavefront Aberrations

Science.gov (United States)

Liu, Yong-Ji; Mu, Guo-Guang; Wang, Zhao-Qi; Wang-Yan

2006-06-01

Monochromatic aberrations in post laser in-situ keratomileusis (LASIK) eyes are measured. The data are categorized into reference group and starburst group according to the visual symptoms. Statistic analysis has been made to find the correlation between the ocular wavefront aberrations and the starburst symptom. The rms aberrations of the 3rd and 4th orders for the starburst group are significantly larger than those for the reference group. The starburst symptom shows a strong correlation with vertical coma, total coma, spherical aberrations. For 3-mm pupil size and 5.8-mm pupil size, the modulation transfer function (MTF) of the starburst group are lower than those of the reference group, but their visual acuities are close. MTF and PSF analyses are made for two groups, and the results are consistent with the statistical analysis, which means the difference between the two groups is mainly due to the third- and fourth-order Zernike aberrations.

Split-plot fractional designs: Is minimum aberration enough?

DEFF Research Database (Denmark)

Kulahci, Murat; Ramirez, Jose; Tobias, Randy

2006-01-01

Split-plot experiments are commonly used in industry for product and process improvement. Recent articles on designing split-plot experiments concentrate on minimum aberration as the design criterion. Minimum aberration has been criticized as a design criterion for completely randomized fractional...... factorial design and alternative criteria, such as the maximum number of clear two-factor interactions, are suggested (Wu and Hamada (2000)). The need for alternatives to minimum aberration is even more acute for split-plot designs. In a standard split-plot design, there are several types of two...... for completely randomized designs. Consequently, we provide a modified version of the maximum number of clear two-factor interactions design criterion to be used for split-plot designs....

Biological dosimetry: chromosomal aberration analysis for dose assessment

International Nuclear Information System (INIS)

1986-01-01

In view of the growing importance of chromosomal aberration analysis as a biological dosimeter, the present report provides a concise summary of the scientific background of the subject and a comprehensive source of information at the technical level. After a review of the basic principles of radiation dosimetry and radiation biology basic information on the biology of lymphocytes, the structure of chromosomes and the classification of chromosomal aberrations are presented. This is followed by a presentation of techniques for collecting blood, storing, transporting, culturing, making chromosomal preparations and scaring of aberrations. The physical and statistical parameters involved in dose assessment are discussed and examples of actual dose assessments taken from the scientific literature are given

Differential algebraic method for arbitrary order curvilinear-axis combined geometric-chromatic aberration analysis

International Nuclear Information System (INIS)

Cheng Min; Tang Tiantong; Lu Yilong; Yao Zhenhua

2003-01-01

The principle of differential algebra is applied to analyse and calculate arbitrary order curvilinear-axis combined geometric-chromatic aberrations of electron optical systems. Expressions of differential algebraic form of high order combined aberrations are obtained and arbitrary order combined aberrations can be calculated numerically. As an example, a typical wide electron beam focusing system with curved optical axes named magnetic immersion lens has been studied. All the second-order and third-order combined geometric-chromatic aberrations of the lens have been calculated, and the patterns of the corresponding geometric aberrations and combined aberrations have been given as well

Population spherical aberration: associations with ametropia, age, corneal curvature, and image quality

Directory of Open Access Journals (Sweden)

Kingston AC

2013-05-01

Full Text Available Amanda C Kingston,1,2 Ian G Cox11Bausch + Lomb, Rochester, NY, USA; 2Department of Biomedical Engineering, University of Rochester, Rochester, NY, USAPurpose: The aim of this analysis was to determine the total ocular wavefront aberration values of a large phakic population of physiologically normal, ametropic eyes, gathered under the same clinical protocol using the same diagnostic wavefront sensor.Materials and methods: Studies were conducted at multiple sites in Asia, North America, Europe, and Australia. A Bausch + Lomb Zywave II Wavefront Aberrometer (Rochester, NY, USA was used to measure the lower and higher order aberrations of each eye. Data analysis was conducted using linear regression analysis to determine the relationship between total spherical aberration, ametropia, age, corneal curvature, and image quality.Results: Linear regression analysis showed no correlation (r = 0.0207, P = 0.4874 between degree of ametropia and the amount of spherical aberration. There was also no correlation when the population was stratified into myopic and hyperopic refractive groups (rm = 0.0529, Pm = 0.0804 and rh = 0.1572, Ph = 0.2754. There was a statistically significant and weak positive correlation (r = 0.1962, P < 0.001 between age and the amount of spherical aberration measured in the eye; spherical aberration became more positive with increasing age. Also, there was a statistically significant and moderately positive correlation (r = 0.3611, P < 0.001 with steepness of corneal curvature; spherical aberration became more positive with increasing power of the anterior corneal surface. Assessment of image quality using optical design software (Zemax™, Bellevue, WA, USA showed that there was an overall benefit in correcting the average spherical aberration of this population.Conclusion: Analysis of this dataset provides insights into the inherent spherical aberration of a typical phakic, pre-presbyopic, population and provides the ability to

Aberration analysis calculations for synchrotron radiation beamline design

International Nuclear Information System (INIS)

McKinney, W.R.; Howells, M.; Padmore, H.A.

1997-09-01

The application of ray deviation calculations based on aberration coefficients for a single optical surface for the design of beamline optical systems is reviewed. A systematic development is presented which allows insight into which aberration may be causing the rays to deviate from perfect focus. A new development allowing analytical calculation of line shape is presented

Fifth-order aberrations in magnetic quadrupole-octupole systems

International Nuclear Information System (INIS)

Ling, K.M.

1990-01-01

Explicit integral expressions are given for the fifth-order geometrical aberration coefficients in rectilinear magnetic quadrupole-octupole systems used for the transport of nonrelativistic charged particle beams. The numerical values of the fifth-order geometrical aberration coefficients for a rare earth cobalt (REC) quadrupole doublet are given as an example. 26 refs., 5 figs., 4 tabs

The spatio-temporal dynamics of PKA activity profile during mitosis and its correlation to chromosome segregation

Science.gov (United States)

Vandame, Pauline; Spriet, Corentin; Trinel, Dave; Gelaude, Armance; Caillau, Katia; Bompard, Coralie; Biondi, Emanuele; Bodart, Jean-François

2014-01-01

The cyclic adenosine monophosphate dependent kinase protein (PKA) controls a variety of cellular processes including cell cycle regulation. Here, we took advantages of genetically encoded FRET-based biosensors, using an AKAR-derived biosensor to characterize PKA activity during mitosis in living HeLa cells using a single-cell approach. We measured PKA activity changes during mitosis. HeLa cells exhibit a substantial increase during mitosis, which ends with telophase. An AKAREV T>A inactive form of the biosensor and H89 inhibitor were used to ascertain for the specificity of the PKA activity measured. On a spatial point of view, high levels of activity near to chromosomal plate during metaphase and anaphase were detected. By using the PKA inhibitor H89, we assessed the role of PKA in the maintenance of a proper division phenotype. While this treatment in our hands did not impaired cell cycle progression in a drastic manner, inhibition of PKA leads to a dramatic increase in chromososme misalignement on the spindle during metaphase that could result in aneuploidies. Our study emphasizes the insights that can be gained with genetically encoded FRET-based biosensors, which enable to overcome the shortcomings of classical methologies and unveil in vivo PKA spatiotemporal profiles in HeLa cells. PMID:25485503

The spatio-temporal dynamics of PKA activity profile during mitosis and its correlation to chromosome segregation.

Science.gov (United States)

Vandame, Pauline; Spriet, Corentin; Trinel, Dave; Gelaude, Armance; Caillau, Katia; Bompard, Coralie; Biondi, Emanuele; Bodart, Jean-François

2014-01-01

The cyclic adenosine monophosphate dependent kinase protein (PKA) controls a variety of cellular processes including cell cycle regulation. Here, we took advantages of genetically encoded FRET-based biosensors, using an AKAR-derived biosensor to characterize PKA activity during mitosis in living HeLa cells using a single-cell approach. We measured PKA activity changes during mitosis. HeLa cells exhibit a substantial increase during mitosis, which ends with telophase. An AKAREV T>A inactive form of the biosensor and H89 inhibitor were used to ascertain for the specificity of the PKA activity measured. On a spatial point of view, high levels of activity near to chromosomal plate during metaphase and anaphase were detected. By using the PKA inhibitor H89, we assessed the role of PKA in the maintenance of a proper division phenotype. While this treatment in our hands did not impaired cell cycle progression in a drastic manner, inhibition of PKA leads to a dramatic increase in chromososme misalignement on the spindle during metaphase that could result in aneuploidies. Our study emphasizes the insights that can be gained with genetically encoded FRET-based biosensors, which enable to overcome the shortcomings of classical methologies and unveil in vivo PKA spatiotemporal profiles in HeLa cells.

Mapping child maltreatment risk: a 12-year spatio-temporal analysis of neighborhood influences.

Science.gov (United States)

Gracia, Enrique; López-Quílez, Antonio; Marco, Miriam; Lila, Marisol

2017-10-18

'Place' matters in understanding prevalence variations and inequalities in child maltreatment risk. However, most studies examining ecological variations in child maltreatment risk fail to take into account the implications of the spatial and temporal dimensions of neighborhoods. In this study, we conduct a high-resolution small-area study to analyze the influence of neighborhood characteristics on the spatio-temporal epidemiology of child maltreatment risk. We conducted a 12-year (2004-2015) small-area Bayesian spatio-temporal epidemiological study with all families with child maltreatment protection measures in the city of Valencia, Spain. As neighborhood units, we used 552 census block groups. Cases were geocoded using the family address. Neighborhood-level characteristics analyzed included three indicators of neighborhood disadvantage-neighborhood economic status, neighborhood education level, and levels of policing activity-, immigrant concentration, and residential instability. Bayesian spatio-temporal modelling and disease mapping methods were used to provide area-specific risk estimations. Results from a spatio-temporal autoregressive model showed that neighborhoods with low levels of economic and educational status, with high levels of policing activity, and high immigrant concentration had higher levels of substantiated child maltreatment risk. Disease mapping methods were used to analyze areas of excess risk. Results showed chronic spatial patterns of high child maltreatment risk during the years analyzed, as well as stability over time in areas of low risk. Areas with increased or decreased child maltreatment risk over the years were also observed. A spatio-temporal epidemiological approach to study the geographical patterns, trends over time, and the contextual determinants of child maltreatment risk can provide a useful method to inform policy and action. This method can offer a more accurate description of the problem, and help to inform more

Controlling spatiotemporal chaos in one- and two-dimensional coupled logistic map lattices

International Nuclear Information System (INIS)

Astakhov, V.V.; Anishchenko, V.S.; Strelkova, G.I.; Shabunin, A.V.

1996-01-01

A method of control of spatiotemporal chaos in lattices of coupled maps is proposed in this work. Forms of spatiotemporal perturbations of a system parameter are analytically determined for one- and two-dimensional logistic map lattices with different kinds of coupling to stabilize chosen spatiotemporal states previously unstable. The results are illustrated by numerical simulation. Controlled transition from the regime of spatiotemporal chaos to the previously chosen regular spatiotemporal patterns is demonstrated. copyright 1996 American Institute of Physics

Spatiotemporal dissociation of brain activity underlying threat and reward in social anxiety disorder.

Science.gov (United States)

A Richey, John; Ghane, Merage; Valdespino, Andrew; Coffman, Marika C; Strege, Marlene V; White, Susan W; Ollendick, Thomas H

2017-01-01

Social anxiety disorder (SAD) involves abnormalities in social motivation, which may be independent of well-documented differences in fear and arousal systems. Yet, the neurobiology underlying motivational difficulties in SAD is not well understood. The aim of the current study was to spatiotemporally dissociate reward circuitry dysfunction from alterations in fear and arousal-related neural activity during anticipation and notification of social and non-social reward and punishment. During fMRI acquisition, non-depressed adults with social anxiety disorder (SAD; N = 21) and age-, sex- and IQ-matched control subjects (N = 22) completed eight runs of an incentive delay task, alternating between social and monetary outcomes and interleaved in alternating order between gain and loss outcomes. Adults with SAD demonstrated significantly reduced neural activity in ventral striatum during the anticipation of positive but not negative social outcomes. No differences between the SAD and control groups were observed during anticipation of monetary gain or loss outcomes or during anticipation of negative social images. However, consistent with previous work, the SAD group demonstrated amygdala hyper-activity upon notification of negative social outcomes. Degraded anticipatory processing in bilateral ventral striatum in SAD was constrained exclusively to anticipation of positive social information and dissociable from the effects of negative social outcomes previously observed in the amygdala. Alterations in anticipation-related neural signals may represent a promising target for treatment that is not addressed by available evidence-based interventions, which focus primarily on fear extinction and habituation processes. © The Author (2016). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Lethality of radiation-induced chromosome aberrations in human tumour cell lines with different radiosensitivities.

Science.gov (United States)

Coco-Martin, J M; Ottenheim, C P; Bartelink, H; Begg, A C

1996-03-01

In order to find an explanation for the eventual disappearance of all chromosome aberrations in two radiosensitive human tumour cell lines, the type and stability of different aberration types was investigated in more detail. To classify the aberrations into unstable and stable types, three-colour fluorescence in situ hybridization was performed, including a whole-chromosome probe, a pancentromere probe, and a stain for total DNA. This technique enables the appropriate classification of the aberrations principally by the presence (stable) or not (unstable) of a single centromere per chromosome. Unstable-type aberrations were found to disappear within 7 days (several divisions) in the two radiosensitive and the two radioresistant tumour lines investigated. Stable-type aberrations were found to remain at an approximately constant level over the duration of the experiment (14 days; 8-10 divisions) in the two radioresistant lines. In contrast, the majority of these stable-type aberrations had disappeared by 14 days in the two radiosensitive lines. The previous findings of disappearance of total aberrations in radiosensitive cells was therefore not due to a reduced induction of stable-type aberrations, but the complete disappearance of cells with this aberration type. These results could not be explained by differences in apoptosis or G1 blocks. Two possible explanations for these unexpected findings involve non-random induction of unstable-type aberrations, or lethality of stable-type aberrations. The results suggest caution in the use of stable-type aberration numbers as a predictor for radiosensitivity.

Influence of coma aberration on aperture averaged scintillations in oceanic turbulence

Science.gov (United States)

Luo, Yujuan; Ji, Xiaoling; Yu, Hong

2018-01-01

The influence of coma aberration on aperture averaged scintillations in oceanic turbulence is studied in detail by using the numerical simulation method. In general, in weak oceanic turbulence, the aperture averaged scintillation can be effectively suppressed by means of the coma aberration, and the aperture averaged scintillation decreases as the coma aberration coefficient increases. However, in moderate and strong oceanic turbulence the influence of coma aberration on aperture averaged scintillations can be ignored. In addition, the aperture averaged scintillation dominated by salinity-induced turbulence is larger than that dominated by temperature-induced turbulence. In particular, it is shown that for coma-aberrated Gaussian beams, the behavior of aperture averaged scintillation index is quite different from the behavior of point scintillation index, and the aperture averaged scintillation index is more suitable for characterizing scintillations in practice.

Time-Resolved and Spatio-Temporal Analysis of Complex Cognitive Processes and their Role in Disorders like Developmental Dyscalculia

Science.gov (United States)

Mórocz, István Akos; Janoos, Firdaus; van Gelderen, Peter; Manor, David; Karni, Avi; Breznitz, Zvia; von Aster, Michael; Kushnir, Tammar; Shalev, Ruth

2012-01-01

The aim of this article is to report on the importance and challenges of a time-resolved and spatio-temporal analysis of fMRI data from complex cognitive processes and associated disorders using a study on developmental dyscalculia (DD). Participants underwent fMRI while judging the incorrectness of multiplication results, and the data were analyzed using a sequence of methods, each of which progressively provided more a detailed picture of the spatio-temporal aspect of this disease. Healthy subjects and subjects with DD performed alike behaviorally though they exhibited parietal disparities using traditional voxel-based group analyses. Further and more detailed differences, however, surfaced with a time-resolved examination of the neural responses during the experiment. While performing inter-group comparisons, a third group of subjects with dyslexia (DL) but with no arithmetic difficulties was included to test the specificity of the analysis and strengthen the statistical base with overall fifty-eight subjects. Surprisingly, the analysis showed a functional dissimilarity during an initial reading phase for the group of dyslexic but otherwise normal subjects, with respect to controls, even though only numerical digits and no alphabetic characters were presented. Thus our results suggest that time-resolved multi-variate analysis of complex experimental paradigms has the ability to yield powerful new clinical insights about abnormal brain function. Similarly, a detailed compilation of aberrations in the functional cascade may have much greater potential to delineate the core processing problems in mental disorders. PMID:22368322

Spatiotemporal patterns formed by deformed adhesive in peeling

International Nuclear Information System (INIS)

Yamazaki, Yoshihiro; Toda, Akihiko

2007-01-01

Dynamical properties of peeling an adhesive tape are investigated experimentally as an analogy of sliding friction. An adhesive tape is peeled by pulling an elastic spring connected to the tape. Controlling its spring constant k and pulling speed V, peel force is measured and spatiotemporal patterns formed on the peeled tape by deformed adhesive are observed. It is found that there exist two kinds of adhesive state in peeling front. The emergence of multiple states is caused by the stability of a characteristic structure (tunnel structure) formed by deformed adhesive. Tunnel structures are distributed spatiotemporally on adhesive tape after peeling. Based on the spatiotemporal distribution, a morphology-dynamical phase diagram is constructed on k-V space and is divided into the four regions: (A) uniform pattern with tunnel structure, (B) uniform pattern without tunnel structure, (C) striped pattern with oscillatory peeling, and (D) spatiotemporally coexistent pattern

Screening for aberrant behavior in the nuclear industry

International Nuclear Information System (INIS)

Borofsky, G.L.

1987-01-01

This paper attempts to promote a fuller understanding of how psychological assessment procedures can be used to reduce the threat from aberrant behavior in the nuclear industry. It begins with a discussion of the scientifically based methods that are used by psychologists in constructing, scoring, and interpreting these procedures. This discussion includes an emphasis on the concepts of validity and reliability and their central importance when one is choosing specific psychological screening tools. Criteria for selecting and using psychological assessment procedures when screening for aberrant behavior are also provided. Some commonly used assessment procedures that satisfy these criteria are discussed. A number a psychological assessment procedures specifically recommended for use in screening for aberrant behavior in the nuclear industry are described

Detecting Aberrant Response Patterns in the Rasch Model. Rapport 87-3.

Science.gov (United States)

Kogut, Jan

In this paper, the detection of response patterns aberrant from the Rasch model is considered. For this purpose, a new person fit index, recently developed by I. W. Molenaar (1987) and an iterative estimation procedure are used in a simulation study of Rasch model data mixed with aberrant data. Three kinds of aberrant response behavior are…

Aberrant neuronal activity-induced signaling and gene expression in a mouse model of RASopathy.

Directory of Open Access Journals (Sweden)

Franziska Altmüller

2017-03-01

Full Text Available Noonan syndrome (NS is characterized by reduced growth, craniofacial abnormalities, congenital heart defects, and variable cognitive deficits. NS belongs to the RASopathies, genetic conditions linked to mutations in components and regulators of the Ras signaling pathway. Approximately 50% of NS cases are caused by mutations in PTPN11. However, the molecular mechanisms underlying cognitive impairments in NS patients are still poorly understood. Here, we report the generation and characterization of a new conditional mouse strain that expresses the overactive Ptpn11D61Y allele only in the forebrain. Unlike mice with a global expression of this mutation, this strain is viable and without severe systemic phenotype, but shows lower exploratory activity and reduced memory specificity, which is in line with a causal role of disturbed neuronal Ptpn11 signaling in the development of NS-linked cognitive deficits. To explore the underlying mechanisms we investigated the neuronal activity-regulated Ras signaling in brains and neuronal cultures derived from this model. We observed an altered surface expression and trafficking of synaptic glutamate receptors, which are crucial for hippocampal neuronal plasticity. Furthermore, we show that the neuronal activity-induced ERK signaling, as well as the consecutive regulation of gene expression are strongly perturbed. Microarray-based hippocampal gene expression profiling revealed profound differences in the basal state and upon stimulation of neuronal activity. The neuronal activity-dependent gene regulation was strongly attenuated in Ptpn11D61Y neurons. In silico analysis of functional networks revealed changes in the cellular signaling beyond the dysregulation of Ras/MAPK signaling that is nearly exclusively discussed in the context of NS at present. Importantly, changes in PI3K/AKT/mTOR and JAK/STAT signaling were experimentally confirmed. In summary, this study uncovers aberrant neuronal activity

A hybrid spatio-temporal data indexing method for trajectory databases.

Science.gov (United States)

Ke, Shengnan; Gong, Jun; Li, Songnian; Zhu, Qing; Liu, Xintao; Zhang, Yeting

2014-07-21

In recent years, there has been tremendous growth in the field of indoor and outdoor positioning sensors continuously producing huge volumes of trajectory data that has been used in many fields such as location-based services or location intelligence. Trajectory data is massively increased and semantically complicated, which poses a great challenge on spatio-temporal data indexing. This paper proposes a spatio-temporal data indexing method, named HBSTR-tree, which is a hybrid index structure comprising spatio-temporal R-tree, B*-tree and Hash table. To improve the index generation efficiency, rather than directly inserting trajectory points, we group consecutive trajectory points as nodes according to their spatio-temporal semantics and then insert them into spatio-temporal R-tree as leaf nodes. Hash table is used to manage the latest leaf nodes to reduce the frequency of insertion. A new spatio-temporal interval criterion and a new node-choosing sub-algorithm are also proposed to optimize spatio-temporal R-tree structures. In addition, a B*-tree sub-index of leaf nodes is built to query the trajectories of targeted objects efficiently. Furthermore, a database storage scheme based on a NoSQL-type DBMS is also proposed for the purpose of cloud storage. Experimental results prove that HBSTR-tree outperforms TB*-tree in some aspects such as generation efficiency, query performance and query type.

A Hybrid Spatio-Temporal Data Indexing Method for Trajectory Databases

Directory of Open Access Journals (Sweden)

Shengnan Ke

2014-07-01

Full Text Available In recent years, there has been tremendous growth in the field of indoor and outdoor positioning sensors continuously producing huge volumes of trajectory data that has been used in many fields such as location-based services or location intelligence. Trajectory data is massively increased and semantically complicated, which poses a great challenge on spatio-temporal data indexing. This paper proposes a spatio-temporal data indexing method, named HBSTR-tree, which is a hybrid index structure comprising spatio-temporal R-tree, B*-tree and Hash table. To improve the index generation efficiency, rather than directly inserting trajectory points, we group consecutive trajectory points as nodes according to their spatio-temporal semantics and then insert them into spatio-temporal R-tree as leaf nodes. Hash table is used to manage the latest leaf nodes to reduce the frequency of insertion. A new spatio-temporal interval criterion and a new node-choosing sub-algorithm are also proposed to optimize spatio-temporal R-tree structures. In addition, a B*-tree sub-index of leaf nodes is built to query the trajectories of targeted objects efficiently. Furthermore, a database storage scheme based on a NoSQL-type DBMS is also proposed for the purpose of cloud storage. Experimental results prove that HBSTR-tree outperforms TB*-tree in some aspects such as generation efficiency, query performance and query type.

A Hybrid Spatio-Temporal Data Indexing Method for Trajectory Databases

Science.gov (United States)

Ke, Shengnan; Gong, Jun; Li, Songnian; Zhu, Qing; Liu, Xintao; Zhang, Yeting

2014-01-01

In recent years, there has been tremendous growth in the field of indoor and outdoor positioning sensors continuously producing huge volumes of trajectory data that has been used in many fields such as location-based services or location intelligence. Trajectory data is massively increased and semantically complicated, which poses a great challenge on spatio-temporal data indexing. This paper proposes a spatio-temporal data indexing method, named HBSTR-tree, which is a hybrid index structure comprising spatio-temporal R-tree, B*-tree and Hash table. To improve the index generation efficiency, rather than directly inserting trajectory points, we group consecutive trajectory points as nodes according to their spatio-temporal semantics and then insert them into spatio-temporal R-tree as leaf nodes. Hash table is used to manage the latest leaf nodes to reduce the frequency of insertion. A new spatio-temporal interval criterion and a new node-choosing sub-algorithm are also proposed to optimize spatio-temporal R-tree structures. In addition, a B*-tree sub-index of leaf nodes is built to query the trajectories of targeted objects efficiently. Furthermore, a database storage scheme based on a NoSQL-type DBMS is also proposed for the purpose of cloud storage. Experimental results prove that HBSTR-tree outperforms TB*-tree in some aspects such as generation efficiency, query performance and query type. PMID:25051028

Effects of ocular aberrations on contrast detection in noise.

Science.gov (United States)

Liang, Bo; Liu, Rong; Dai, Yun; Zhou, Jiawei; Zhou, Yifeng; Zhang, Yudong

2012-08-06

We use adaptive optics (AO) techniques to manipulate the ocular aberrations and elucidate the effects of these ocular aberrations on contrast detection in a noisy background. The detectability of sine wave gratings at frequencies of 4, 8, and 16 circles per degree (cpd) was measured in a standard two-interval force-choice staircase procedure against backgrounds of various levels of white noise. The observer's ocular aberrations were either corrected with AO or left uncorrected. In low levels of external noise, contrast detection thresholds are always lowered by AO correction, whereas in high levels of external noise, they are generally elevated by AO correction. Higher levels of external noise are required to make this threshold elevation observable when signal spatial frequencies increase from 4 to 16 cpd. The linear-amplifier-model fit shows that mostly sampling efficiency and equivalent noise both decrease with AO correction. Our findings indicate that ocular aberrations could be beneficial for contrast detection in high-level noises. The implications of these findings are discussed.

Chromosome aberrations and cell survival in irradiated mammalian cells

International Nuclear Information System (INIS)

Tremp, J.

1981-01-01

A possible correlation between chromosome aberrations and reduced proliferation capacity or cell death was investigated. Synchronized Chinese hamster fibroblast cells were irradiated with 300 rad of x rays in early G 1 . Despite synchronization the cells reached the subsequent mitosis at different times. The frequency of chromosome aberrations was determined in the postirradiation division at 2-h intervals. The highest frequency occurred in cells with a first cell cycle of medium length. The colony-forming ability of mitotic cells was measured in parallel samples by following the progress of individual mitoses. The proportion of cells forming macrocolonies decreased with increasing cell cycle length, and the number of non-colony-forming cells increased. Irrespective of various first cell cycle lengths and different frequencies of chromosome aberrations, the number of cells forming microcolonies remained constant. A correlation was found between the absence of chromosome aberrations and the ability of cells to form macrocolonies. However, cells with a long first cell cycle formed fewer macrocolonies than expected

Design for an aberration corrected scanning electron microscope using miniature electron mirrors.

Science.gov (United States)

Dohi, Hideto; Kruit, Pieter

2018-06-01

Resolution of scanning electron microscopes (SEMs) is determined by aberrations of the objective lens. It is well known that both spherical and chromatic aberrations can be compensated by placing a 90-degree bending magnet and an electron mirror in the beam path before the objective lens. Nevertheless, this approach has not led to wide use of these aberration correctors, partly because aberrations of the bending magnet can be a serious problem. A mirror corrector with two mirrors placed perpendicularly to the optic axis of an SEM and facing each other is proposed. As a result, only small-angle magnetic deflection is necessary to guide the electron beam around the top mirror to the bottom mirror and around the bottom mirror to the objective lens. The deflection angle, in the order of 50 mrad, is sufficiently small to avoid deflection aberrations. In addition, lateral dispersion at the sample plane can be avoided by making the deflection fields symmetric. Such a corrector system is only possible if the incoming beam can pass the top mirror at a distance in the order of millimeters, without being disturbed by the electric fields of electrodes of the mirror. It is proposed that condition can be satisfied with micro-scale electron optical elements fabricated by using MEMS technology. In the proposed corrector system, the micro-mirrors have to provide the exact negative spherical and chromatic aberrations for correcting the aberration of the objective lens. This exact tuning is accomplished by variable magnification between the micro-mirrors and the objective lens using an additional transfer lens. Extensive optical calculations are reported. Aberrations of the micro-mirrors were analyzed by numerical calculation. Dispersion and aberrations of the deflectors were calculated by using an analytical field model. Combination aberrations caused by the off-axis position of dispersive rays in the mirrors and objective lens were also analyzed. It is concluded that the proposed

Electrostatic axisymmetric mirror with removable spherical aberration

International Nuclear Information System (INIS)

Birmuzaev, S.B.; Serikbaeva, G.S.; Hizirova, M.A.

1999-01-01

The electrostatic axisymmetric mirror, assembled from three coaxial cylinders with an equal diameter d and under the potential v1, v2 and v3, was computed. The proportions of geometrical and electric parameters of the mirror, with which the spherical 3-order aberration may be eliminated, were determined. The computation outcomes of the case, when the focal power of the mirror is enough large and the object plane in the focus is out of its field, are presented (Fig. 1 - potentials proportion that makes elimination of the spherical aberration possible; Fig. 2 - the focus coordinates when the spherical aberration is eliminated). The geometrical values are presented by d, and the electric ones are presented by v1. The figures on the curves present a length of the second (middle) electrode. The zero point is located in the middle of the gap between the first and second electrodes The investigated mirror may be used as a lens for the transmission electron microscope

An accurate optical design method for synchrotron radiation beamlines with wave-front aberration theory

Energy Technology Data Exchange (ETDEWEB)

Yu, Xiaojiang, E-mail: slsyxj@nus.edu.sg; Diao, Caozheng; Breese, Mark B. H. [Singapore Synchrotron Light Source, National University of Singapore, Singapore 117603 (Singapore)

2016-07-27

An aberration calculation method which was developed by Lu [1] can treat individual aberration term precisely. Spectral aberration is the linear sum of these aberration terms, and the aberrations of multi-element systems also can be calculated correctly when the stretching ratio, defined herein, is unity. Evaluation of focusing mirror-grating systems which are optimized according to Lu’s method, along with the Light Path Function (LPF) and the Spot Diagram method (SD) are discussed to confirm the advantage of Lu’s methodology. Lu’s aberration terms are derived from a precise wave-front treatment, whereas the terms of the power series expansion of the light path function do not yield an accurate sum of the aberrations. Moreover, Lu’s aberration terms can be individually optimized. This is not possible with the analytical spot diagram formulae.

Construction of special eye models for investigation of chromatic and higher-order aberrations of eyes.

Science.gov (United States)

Zhai, Yi; Wang, Yan; Wang, Zhaoqi; Liu, Yongji; Zhang, Lin; He, Yuanqing; Chang, Shengjiang

2014-01-01

An achromatic element eliminating only longitudinal chromatic aberration (LCA) while maintaining transverse chromatic aberration (TCA) is established for the eye model, which involves the angle formed by the visual and optical axis. To investigate the impacts of higher-order aberrations on vision, the actual data of higher-order aberrations of human eyes with three typical levels are introduced into the eye model along visual axis. Moreover, three kinds of individual eye models are established to investigate the impacts of higher-order aberrations, chromatic aberration (LCA+TCA), LCA and TCA on vision under the photopic condition, respectively. Results show that for most human eyes, the impact of chromatic aberration on vision is much stronger than that of higher-order aberrations, and the impact of LCA in chromatic aberration dominates. The impact of TCA is approximately equal to that of normal level higher-order aberrations and it can be ignored when LCA exists.

Aberrant alternative splicing is another hallmark of cancer.

Science.gov (United States)

Ladomery, Michael

2013-01-01

The vast majority of human genes are alternatively spliced. Not surprisingly, aberrant alternative splicing is increasingly linked to cancer. Splice isoforms often encode proteins that have distinct and even antagonistic properties. The abnormal expression of splice factors and splice factor kinases in cancer changes the alternative splicing of critically important pre-mRNAs. Aberrant alternative splicing should be added to the growing list of cancer hallmarks.

Aberrant Alternative Splicing Is Another Hallmark of Cancer

OpenAIRE

Ladomery, Michael

2013-01-01

The vast majority of human genes are alternatively spliced. Not surprisingly, aberrant alternative splicing is increasingly linked to cancer. Splice isoforms often encode proteins that have distinct and even antagonistic properties. The abnormal expression of splice factors and splice factor kinases in cancer changes the alternative splicing of critically important pre-mRNAs. Aberrant alternative splicing should be added to the growing list of cancer hallmarks.

Community ecology in 3D: Tensor decomposition reveals spatio-temporal dynamics of large ecological communities

DEFF Research Database (Denmark)

Frelat, Romain; Lindegren, Martin; Dencker, Tim Spaanheden

2017-01-01

it to multiple dimensions. This extension allows for the synchronized study of multiple ecological variables measured repeatedly in time and space. We applied this comprehensive approach to explore the spatio-temporal dynamics of 65 demersal fish species in the North Sea, a marine ecosystem strongly altered...... by human activities and climate change. Our case study demonstrates how tensor decomposition can successfully (i) characterize the main spatio-temporal patterns and trends in species abundances, (ii) identify sub-communities of species that share similar spatial distribution and temporal dynamics, and (iii...

Neurogenomic signatures of spatiotemporal memories in time-trained forager honey bees

Science.gov (United States)

Naeger, Nicholas L.; Van Nest, Byron N.; Johnson, Jennifer N.; Boyd, Sam D.; Southey, Bruce R.; Rodriguez-Zas, Sandra L.; Moore, Darrell; Robinson, Gene E.

2011-01-01

Honey bees can form distinct spatiotemporal memories that allow them to return repeatedly to different food sources at different times of day. Although it is becoming increasingly clear that different behavioral states are associated with different profiles of brain gene expression, it is not known whether this relationship extends to states that are as dynamic and specific as those associated with foraging-related spatiotemporal memories. We tested this hypothesis by training different groups of foragers from the same colony to collect sucrose solution from one of two artificial feeders; each feeder was in a different location and had sucrose available at a different time, either in the morning or afternoon. Bees from both training groups were collected at both the morning and afternoon training times to result in one set of bees that was undergoing stereotypical food anticipatory behavior and another that was inactive for each time of day. Between the two groups with the different spatiotemporal memories, microarray analysis revealed that 1329 genes were differentially expressed in the brains of honey bees. Many of these genes also varied with time of day, time of training or state of food anticipation. Some of these genes are known to be involved in a variety of biological processes, including metabolism and behavior. These results indicate that distinct spatiotemporal foraging memories in honey bees are associated with distinct neurogenomic signatures, and the decomposition of these signatures into sets of genes that are also influenced by time or activity state hints at the modular composition of this complex neurogenomic phenotype. PMID:21346126

Screening of clonal chromosome aberrations present in A-bomb survivors by FISH method

International Nuclear Information System (INIS)

Nakano, Mimako; Kodama, Yoshiaki; Ito, Masahiro; Otaki, Kazuo; Nakamura, Nori

1997-01-01

Significance of FISH method for detection of clonal chromosome aberration was reviewed. A clonal chromosome aberration is derived from one abnormal cell clone and gives the influence on the frequency of the aberration. As well, the size and frequency of the aberration give an important information concerning lymphocyte kinetics. FISH method is meaningful for detection of the clonal aberration. Fifteen kinds of clonal aberrations were detected in A-bomb survivors, of which 10 were specifically detected by the method, indicating that its detection rate was 2-3 time as high as the ordinary method. The results were those on the DNA probe on no.1, no.2 and no.3 chromosomes, which consisting of about 23% of the genome. (K.H.)

TNFRSF14 aberrations in follicular lymphoma increase clinically significant allogeneic T-cell responses.

Science.gov (United States)

Kotsiou, Eleni; Okosun, Jessica; Besley, Caroline; Iqbal, Sameena; Matthews, Janet; Fitzgibbon, Jude; Gribben, John G; Davies, Jeffrey K

2016-07-07

Donor T-cell immune responses can eradicate lymphomas after allogeneic hematopoietic stem cell transplantation (AHSCT), but can also damage healthy tissues resulting in harmful graft-versus-host disease (GVHD). Next-generation sequencing has recently identified many new genetic lesions in follicular lymphoma (FL). One such gene, tumor necrosis factor receptor superfamily 14 (TNFRSF14), abnormal in 40% of FL patients, encodes the herpes virus entry mediator (HVEM) which limits T-cell activation via ligation of the B- and T-lymphocyte attenuator. As lymphoma B cells can act as antigen-presenting cells, we hypothesized that TNFRSF14 aberrations that reduce HVEM expression could alter the capacity of FL B cells to stimulate allogeneic T-cell responses and impact the outcome of AHSCT. In an in vitro model of alloreactivity, human lymphoma B cells with TNFRSF14 aberrations had reduced HVEM expression and greater alloantigen-presenting capacity than wild-type lymphoma B cells. The increased immune-stimulatory capacity of lymphoma B cells with TNFRSF14 aberrations had clinical relevance, associating with higher incidence of acute GVHD in patients undergoing AHSCT. FL patients with TNFRSF14 aberrations may benefit from more aggressive immunosuppression to reduce harmful GVHD after transplantation. Importantly, this study is the first to demonstrate the impact of an acquired genetic lesion on the capacity of tumor cells to stimulate allogeneic T-cell immune responses which may have wider consequences for adoptive immunotherapy strategies. © 2016 by The American Society of Hematology.

The MLH1 ATPase domain is needed for suppressing aberrant formation of interstitial telomeric sequences.

Science.gov (United States)

Jia, Pingping; Chai, Weihang

2018-05-01

Genome instability gives rise to cancer. MLH1, commonly known for its important role in mismatch repair (MMR), DNA damage signaling and double-strand break (DSB) repair, safeguards genome stability. Recently we have reported a novel role of MLH1 in preventing aberrant formation of interstitial telomeric sequences (ITSs) at intra-chromosomal regions. Deficiency in MLH1, in particular its N-terminus, leads to an increase of ITSs. Here, we identify that the ATPase activity in the MLH1 N-terminal domain is important for suppressing the formation of ITSs. The ATPase activity is also needed for recruiting MLH1 to DSBs. Moreover, defective ATPase activity of MLH1 causes an increase in micronuclei formation. Our results highlight the crucial role of MLH1's ATPase domain in preventing the aberrant formation of telomeric sequences at the intra-chromosomal regions and preserving genome stability. Copyright © 2018 Elsevier B.V. All rights reserved.

Transitionality in addiction: A "temporal continuum" hypotheses involving the aberrant motivation, the hedonic dysregulation, and the aberrant learning.

Science.gov (United States)

Patrono, Enrico; Gasbarri, Antonella; Tomaz, Carlos; Nishijo, Hisao

2016-08-01

Addiction is a chronic compulsion and relapsing disorder. It involves several brain areas and circuits, which encode vary functions such as reward, motivation, and memory. Drug addiction is defined as a "pathological pattern of use of a substance", characterized by the loss of control on drug-taking-related behaviors, the pursuance of those behaviors even in the presence of negative consequences, and a strong motivated activity to assume substances. Three different theories guide experimental research on drug addiction. Each of these theories consider singles features, such as an aberrant motivation, a hedonic dysregulation, and an aberrant habit learning as the main actor to explain the entire process of the addictive behaviors. The major goal of this study is to present a new hypotheses of transitionality from a controlled use to abuse of addictive substances trough the overview of the three different theories, considering all the single features of each single theory together on the same "temporal continuum" from use to abuse of addictive substances. Recently, it has been suggested that common neural systems may be activated by natural and pharmacological stimuli, raising the hypotheses that binge-eating disorders could be considered as addictive behaviors. The second goal of this study is to present evidences in order to highlight a possible psycho-bio-physiological superimposition between drug and "food addiction". Finally, interesting questions are brought up starting from last findings about a theoretical/psycho-bio-physiological superimposition between drug and "food addiction" and their possibly same transitionality along the same "temporal continuum" from use to abuse of addictive substances in order to investigate new therapeutic strategies based on new therapeutic strategies based on the individual moments characterizing the transition from the voluntary intake of substances to the maladaptive addictive behavior. Copyright © 2016. Published by Elsevier

Study of wavefront aberration in DR patients with different degree of dry eye

Directory of Open Access Journals (Sweden)

Jin-Ran Fang

2018-05-01

Full Text Available AIM: To compare the changes of wavefront aberrations in patients with diabetic retinopathy(DRand with different degrees of dry eye and to explore the reasons of visual quality decline in them. METHODS: We randomly selected 40 eyes in our hospital for treatment with DR and varying degrees of dry eye, and 40 eyes of normal control group. Topcon KR-1W visual quality analyzer was used to record the mean square the total high order corneal aberration, spherical aberration, comatic aberration and trefoil aberration of cornea with pupil diameters of 4mm and 6mm. Analysis of variance were used to compare the wavefront aberrations and the aberration values in the control group and in patients with diabetic retinopathy and with different degrees of dry eye. RESULTS: For 4mm and 6mm pupil diameters, nondiabetic retinopathy(NDRwith dry eye group, the nonproliferative diabetic retinopathy(NPDRwith dry eye group and proliferative diabetic retinopathy(PDRdry eye group had significantly increased tHOA, coma and trefoil compared with the contrast group(PPCONCLUSION: Dry eye of diabetic retinopathy with different degrees is closely related to the increase of wavefront aberration. Increased wavefront aberration may be one of the reasons to reduced visual quality in patients with diabetic retinopathy and with dry eye, and provide the basis for the decline of visual function of diabetic patients with dry eye.

Full-Scale Approximations of Spatio-Temporal Covariance Models for Large Datasets

KAUST Repository

Zhang, Bohai

2014-01-01

Various continuously-indexed spatio-temporal process models have been constructed to characterize spatio-temporal dependence structures, but the computational complexity for model fitting and predictions grows in a cubic order with the size of dataset and application of such models is not feasible for large datasets. This article extends the full-scale approximation (FSA) approach by Sang and Huang (2012) to the spatio-temporal context to reduce computational complexity. A reversible jump Markov chain Monte Carlo (RJMCMC) algorithm is proposed to select knots automatically from a discrete set of spatio-temporal points. Our approach is applicable to nonseparable and nonstationary spatio-temporal covariance models. We illustrate the effectiveness of our method through simulation experiments and application to an ozone measurement dataset.

Neural speech recognition: continuous phoneme decoding using spatiotemporal representations of human cortical activity

Science.gov (United States)

Moses, David A.; Mesgarani, Nima; Leonard, Matthew K.; Chang, Edward F.

2016-10-01

Objective. The superior temporal gyrus (STG) and neighboring brain regions play a key role in human language processing. Previous studies have attempted to reconstruct speech information from brain activity in the STG, but few of them incorporate the probabilistic framework and engineering methodology used in modern speech recognition systems. In this work, we describe the initial efforts toward the design of a neural speech recognition (NSR) system that performs continuous phoneme recognition on English stimuli with arbitrary vocabulary sizes using the high gamma band power of local field potentials in the STG and neighboring cortical areas obtained via electrocorticography. Approach. The system implements a Viterbi decoder that incorporates phoneme likelihood estimates from a linear discriminant analysis model and transition probabilities from an n-gram phonemic language model. Grid searches were used in an attempt to determine optimal parameterizations of the feature vectors and Viterbi decoder. Main results. The performance of the system was significantly improved by using spatiotemporal representations of the neural activity (as opposed to purely spatial representations) and by including language modeling and Viterbi decoding in the NSR system. Significance. These results emphasize the importance of modeling the temporal dynamics of neural responses when analyzing their variations with respect to varying stimuli and demonstrate that speech recognition techniques can be successfully leveraged when decoding speech from neural signals. Guided by the results detailed in this work, further development of the NSR system could have applications in the fields of automatic speech recognition and neural prosthetics.

Aberrant hepatic artery

International Nuclear Information System (INIS)

Konstam, M.A.; Novelline, R.A.; Athanasoulis, C.A.

1979-01-01

In a patient undergoing selective hepatic arteriography for suspected liver trauma, a nonopacified area of the liver, initially thought to represent a hepatic hematoma, was later discovered to be due to the presence of an accessory right hepatic artery arising from the superior mesenteric artery. This case illustrates the need for a search for aberrant vasculature whenever a liver hematoma is suspected on the basis of a selective hepatic arteriogram. (orig.) [de

Stress Sensitivity, Aberrant Salience, and Threat Anticipation in Early Psychosis: An Experience Sampling Study

Science.gov (United States)

Reininghaus, Ulrich; Kempton, Matthew J.; Valmaggia, Lucia; Craig, Tom K. J.; Garety, Philippa; Onyejiaka, Adanna; Gayer-Anderson, Charlotte; So, Suzanne H.; Hubbard, Kathryn; Beards, Stephanie; Dazzan, Paola; Pariante, Carmine; Mondelli, Valeria; Fisher, Helen L.; Mills, John G.; Viechtbauer, Wolfgang; McGuire, Philip; van Os, Jim; Murray, Robin M.; Wykes, Til; Myin-Germeys, Inez; Morgan, Craig

2016-01-01

While contemporary models of psychosis have proposed a number of putative psychological mechanisms, how these impact on individuals to increase intensity of psychotic experiences in real life, outside the research laboratory, remains unclear. We aimed to investigate whether elevated stress sensitivity, experiences of aberrant novelty and salience, and enhanced anticipation of threat contribute to the development of psychotic experiences in daily life. We used the experience sampling method (ESM) to assess stress, negative affect, aberrant salience, threat anticipation, and psychotic experiences in 51 individuals with first-episode psychosis (FEP), 46 individuals with an at-risk mental state (ARMS) for psychosis, and 53 controls with no personal or family history of psychosis. Linear mixed models were used to account for the multilevel structure of ESM data. In all 3 groups, elevated stress sensitivity, aberrant salience, and enhanced threat anticipation were associated with an increased intensity of psychotic experiences. However, elevated sensitivity to minor stressful events (χ2 = 6.3, P = 0.044), activities (χ2 = 6.7, P = 0.036), and areas (χ2 = 9.4, P = 0.009) and enhanced threat anticipation (χ2 = 9.3, P = 0.009) were associated with more intense psychotic experiences in FEP individuals than controls. Sensitivity to outsider status (χ2 = 5.7, P = 0.058) and aberrantly salient experiences (χ2 = 12.3, P = 0.002) were more strongly associated with psychotic experiences in ARMS individuals than controls. Our findings suggest that stress sensitivity, aberrant salience, and threat anticipation are important psychological processes in the development of psychotic experiences in daily life in the early stages of the disorder. PMID:26834027

Pathophysiology of MDS: genomic aberrations.

Science.gov (United States)

Ichikawa, Motoshi

2016-01-01

Myelodysplastic syndromes (MDS) are characterized by clonal proliferation of hematopoietic stem/progenitor cells and their apoptosis, and show a propensity to progress to acute myelogenous leukemia (AML). Although MDS are recognized as neoplastic diseases caused by genomic aberrations of hematopoietic cells, the details of the genetic abnormalities underlying disease development have not as yet been fully elucidated due to difficulties in analyzing chromosomal abnormalities. Recent advances in comprehensive analyses of disease genomes including whole-genome sequencing technologies have revealed the genomic abnormalities in MDS. Surprisingly, gene mutations were found in approximately 80-90% of cases with MDS, and the novel mutations discovered with these technologies included previously unknown, MDS-specific, mutations such as those of the genes in the RNA-splicing machinery. It is anticipated that these recent studies will shed new light on the pathophysiology of MDS due to genomic aberrations.

Spatiotemporal Stochastic Resonance:Theory and Experiment

Science.gov (United States)

Peter, Jung

1996-03-01

The amplification of weak periodic signals in bistable or excitable systems via stochastic resonance has been studied intensively over the last years. We are going one step further and ask: Can noise enhance spatiotemporal patterns in excitable media and can this effect be observed in nature? To this end, we are looking at large, two dimensional arrays of coupled excitable elements. Due to the coupling, excitation can propagate through the array in form of nonlinear waves. We observe target waves, rotating spiral waves and other wave forms. If the coupling between the elements is below a critical threshold, any excitational pattern will die out in the absence of noise. Below this threshold, large scale rotating spiral waves - as they are observed above threshold - can be maintained by a proper level of the noise[1]. Furthermore, their geometric features, such as the curvature can be controlled by the homogeneous noise level[2]. If the noise level is too large, break up of spiral waves and collisions with spontaneously nucleated waves yields spiral turbulence. Driving our array with a spatiotemporal pattern, e.g. a rotating spiral wave, we show that for weak coupling the excitational response of the array shows stochastic resonance - an effect we have termed spatiotemporal stochastic resonance. In the last part of the talk I'll make contact with calcium waves, observed in astrocyte cultures and hippocampus slices[3]. A. Cornell-Bell and collaborators[3] have pointed out the role of calcium waves for long-range glial signaling. We demonstrate the similarity of calcium waves with nonlinear waves in noisy excitable media. The noise level in the tissue is characterized by spontaneous activity and can be controlled by applying neuro-transmitter substances[3]. Noise effects in our model are compared with the effect of neuro-transmitters on calcium waves. [1]P. Jung and G. Mayer-Kress, CHAOS 5, 458 (1995). [2]P. Jung and G. Mayer-Kress, Phys. Rev. Lett.62, 2682 (1995). [3

A hybrid spatiotemporal drought forecasting model for operational use

Science.gov (United States)

Vasiliades, L.; Loukas, A.

2010-09-01

Drought forecasting plays an important role in the planning and management of natural resources and water resource systems in a river basin. Early and timelines forecasting of a drought event can help to take proactive measures and set out drought mitigation strategies to alleviate the impacts of drought. Spatiotemporal data mining is the extraction of unknown and implicit knowledge, structures, spatiotemporal relationships, or patterns not explicitly stored in spatiotemporal databases. As one of data mining techniques, forecasting is widely used to predict the unknown future based upon the patterns hidden in the current and past data. This study develops a hybrid spatiotemporal scheme for integrated spatial and temporal forecasting. Temporal forecasting is achieved using feed-forward neural networks and the temporal forecasts are extended to the spatial dimension using a spatial recurrent neural network model. The methodology is demonstrated for an operational meteorological drought index the Standardized Precipitation Index (SPI) calculated at multiple timescales. 48 precipitation stations and 18 independent precipitation stations, located at Pinios river basin in Thessaly region, Greece, were used for the development and spatiotemporal validation of the hybrid spatiotemporal scheme. Several quantitative temporal and spatial statistical indices were considered for the performance evaluation of the models. Furthermore, qualitative statistical criteria based on contingency tables between observed and forecasted drought episodes were calculated. The results show that the lead time of forecasting for operational use depends on the SPI timescale. The hybrid spatiotemporal drought forecasting model could be operationally used for forecasting up to three months ahead for SPI short timescales (e.g. 3-6 months) up to six months ahead for large SPI timescales (e.g. 24 months). The above findings could be useful in developing a drought preparedness plan in the region.

Frequency of primary amenorrhea due to chromosomal aberration

International Nuclear Information System (INIS)

Jabbar, S.

2004-01-01

Objective: To find out the frequency of primary amenorrhea due to chromosomal aberration and the different options available for management. Subjects and Methods: All patients with primary amenorrhea due to chromosomal aberrations were included in study. Patient's detailed history, general physical examination, presence or absence of secondary sexual characteristics, abdominal and pelvic examination finding were noted. Targeted investigations, including ultrasound, hormonal assay, buccal smear and karyotyping results were recorded. The management options were individually tailored with focus n psychological management. Results: Eighteen patients out of 30,000 patients were diagnosed as having primary amenorrhea. Six had primary amenorrhea due to chromosomal aberrations with the frequency of 0.02%. The age at presentation was 20 years and above in 50%. The most common cause was Turner's syndrome seen in 4 out of 6. The presenting symptoms were delay in onset of menstruation in 05 patients and primary infertility in 01 patient. Conclusion: Primary amenorrhea due to chromosomal aberration is an uncommon condition requiring an early and accurate diagnosis. Turner's syndrome is a relatively common cause of this condition. Management should be multi-disciplinary and individualized according to the patient's age and symptom at presentation. Psychological management is very important and counselling throughout treatment is recommended. (author)

Use of unstable chromosome aberrations for biological dosimetry after the first postirradiation mitosis

International Nuclear Information System (INIS)

Doloy, M.T.; Malarbet, J.L.; Guedeney, G.; Bourguignon, M.; Leroy, A.; Reillaudou, M.; Masse, R.

1991-01-01

The loss of unstable chromosome aberrations after the first postirradiation mitosis makes their use difficult in radiation dosimetry. We describe here a method which, in a cell population observed at this stage, allows retrospective estimation of the frequencies of the unstable aberrations induced at the time of irradiation, and their use as a dosimeter. The laws controlling the behavior of unstable aberrations during mitosis were defined from a large-scale experiment on irradiated human lymphocytes. For cells undergoing the first, second, or third mitosis after irradiation, relationships were determined between the frequency, at irradiation time, of acentric fragments not arising from formation of dicentrics or rings, and the ratio of dicentrics and centric rings appearing without acentric fragments to the total number of dicentrics plus rings. On the basis of this ratio, the method described here provides an assessment of the postirradiation mitotic activity in a cell population. This assessment permitted estimation of the cell distribution and frequency of dicentrics plus centric rings, and of the frequency of acentric fragments at the time of irradiation. The use of this method for retrospective dosimetry after whole-body irradiation under various conditions of exposure is illustrated

An aberrant uterus: Case report | Ondieki | East African Medical ...

African Journals Online (AJOL)

A case of an aberrant uterus is presented and literature reviewed. The patient presented with abnormal uterine bleeding, left iliac fossa pain and was managed by excising the aberrant uterus. This case was an enigma as it didn't present in the classical way one with anomalies of the uterus would present. Despite ...

Related research on corneal higher-order aberrations after different ways refractive surgery

Directory of Open Access Journals (Sweden)

Shu-Xi He

2015-08-01

Full Text Available AIM:To evaluate the changes of corneal high-order aberration(including Coma, Spab, RMShafter laser in situ keratomileusis(LASIKwith femtosecond laser, sub-Bowman keratomileusis(SBKand laser epithelial keratomileusis(LASEK.METHODS: Of 82 myopic patients(164 eyes, 31 patients(62 eyeswere treated by FS-LASIK, 31 patients(62 eyeswere treated by SBK, 20 patients(40 eyeswere treated by LASEK. Sirius system was used for measuring the coma aberration, spherical aberration, and high order aberration at 1, 15d,1, 3mo after surgery.RESULTS: 1Vision: The uncorrected visual acuity of the three groups had no differences(P>0.05. 2Corneal aberrations: Three kinds of surgical procedure for patients with corneal aberration had significant impact. The C7, C8, C12 and RMSh of three groups were increased significantly(P0.05. The C7, C8, C12 and RMSh were not recovered to preoperative levels after 3mo. But the increase of patients after FS-LASIK was smaller than the other two groups, with statistical significance(P0.05.CONCLUSION: Compared with SBK and LASEK,FS-LASIK has better visual acuity in the early postoperative and corneal higher-order aberrations increase is relatively small.

Chromosome aberrations in Norwegian reindeer following the Chernobyl accident

International Nuclear Information System (INIS)

Røed, K.H.; Jacobsen, M.

1995-01-01

Chromosome analyses were carried out on peripheral blood lymphocytes of semi-domestic reindeer in Norway which had been exposed to varying amounts of radiocesium emanating from the Chernobyl accident. The sampling was done in the period 1987-1990. The material included 192 reindeer, originating from four herds in central Norway, an area considerably affected by fallout from the Chernobyl accident, and from three herds in northern Norway which was unaffected by fallout from the accident. Significant heterogeneity in the distribution of chromosome aberrations between herds was observed. The pattern of chromosome aberration frequencies between herds was not related to the variation in radiocesium exposure from the Chernobyl accident. Other factors than the Chernobyl accident appear therefore to be of importance for the distribution of aberration frequencies found among present herds. Within the most contaminated area the reindeer born in 1986 showed significantly more chromosome aberrations than those born both before and after 1986. This could suggest that the Chernobyl accident fallout created an effect particularly among calves, during the immediate post-accident period in the most exposed areas

Novel plumage aberrations in Paraguayan non-Passerine Birds, and the definition of a new plumage aberration unique to Psittacidae

Directory of Open Access Journals (Sweden)

Paul Smith

2017-07-01

Full Text Available Anomalous plumage colourations are reported for three species of non-passerine birds from Paraguay, Limpkin (Aramaus guarauna; Aramidae, Nanday Parakeet (Nandayus nenday; Psittacidae, and the Little Woodpecker (Veniliornis passerinus; Picidae. A leucistic Limpkin is the first published report of a colour anomaly for the family Aramidae. The colour aberration in N. nenday is hypothesised to be a result of an excess of red psittacofulvin pigments, which are unique to the Psittacidae. Although the mechanisms causing this colour aberration remain unknown, we suggest the term psittacofulvism for the phenotypic effect observed.

Spatiotemporal drought forecasting using nonlinear models

Science.gov (United States)

Vasiliades, Lampros; Loukas, Athanasios

2010-05-01

Spatiotemporal data mining is the extraction of unknown and implicit knowledge, structures, spatiotemporal relationships, or patterns not explicitly stored in spatiotemporal databases. As one of data mining techniques, forecasting is widely used to predict the unknown future based upon the patterns hidden in the current and past data. In order to achieve spatiotemporal forecasting, some mature analysis tools, e.g., time series and spatial statistics are extended to the spatial dimension and the temporal dimension, respectively. Drought forecasting plays an important role in the planning and management of natural resources and water resource systems in a river basin. Early and timelines forecasting of a drought event can help to take proactive measures and set out drought mitigation strategies to alleviate the impacts of drought. Despite the widespread application of nonlinear mathematical models, comparative studies on spatiotemporal drought forecasting using different models are still a huge task for modellers. This study uses a promising approach, the Gamma Test (GT), to select the input variables and the training data length, so that the trial and error workload could be greatly reduced. The GT enables to quickly evaluate and estimate the best mean squared error that can be achieved by a smooth model on any unseen data for a given selection of inputs, prior to model construction. The GT is applied to forecast droughts using monthly Standardized Precipitation Index (SPI) timeseries at multiple timescales in several precipitation stations at Pinios river basin in Thessaly region, Greece. Several nonlinear models have been developed efficiently, with the aid of the GT, for 1-month up to 12-month ahead forecasting. Several temporal and spatial statistical indices were considered for the performance evaluation of the models. The predicted results show reasonably good agreement with the actual data for short lead times, whereas the forecasting accuracy decreases with

Zernike phase spatial filter for measuring the aberrations

OpenAIRE

Svetlana N. Khonina; Victor V. Kotlyar; Dmitriy V. Kirsh

2015-01-01

To measure directly the wavefront aberration coefficients, we propose to use the multi8order diffractive element fitted with the set of Zernike polynomials. Polynomials of lowest degree describe defocusing (ametropy) and astigmatism. Coefficients of highest degree correspond to the spherical aberration of oblique rays that occurs as a consequence of misalignment of the crystalline lens and foveola, as well as deflection at the periphery of the crystalline lens. Mul^order elements allow severa...

Aberration compensation of an ultrasound imaging instrument with a reduced number of channels.

Science.gov (United States)

Jiang, Wei; Astheimer, Jeffrey P; Waag, Robert C

2012-10-01

Focusing and imaging qualities of an ultrasound imaging system that uses aberration correction were experimentally investigated as functions of the number of parallel channels. Front-end electronics that consolidate signals from multiple physical elements can be used to lower hardware and computational costs by reducing the number of parallel channels. However, the signals from sparse arrays of synthetic elements yield poorer aberration estimates. In this study, aberration estimates derived from synthetic arrays of varying element sizes are evaluated by comparing compensated receive focuses, compensated transmit focuses, and compensated b-scan images of a point target and a cyst phantom. An array of 80 x 80 physical elements with a pitch of 0.6 x 0.6 mm was used for all of the experiments and the aberration was produced by a phantom selected to mimic propagation through abdominal wall. The results show that aberration correction derived from synthetic arrays with pitches that have a diagonal length smaller than 70% of the correlation length of the aberration yield focuses and images of approximately the same quality. This connection between correlation length of the aberration and synthetic element size provides a guideline for determining the number of parallel channels that are required when designing imaging systems that employ aberration correction.

Genomic aberrations in spitzoid tumours and their implications for diagnosis, prognosis and therapy

Science.gov (United States)

Wiesner, Thomas; Kutzner, Heinz; Cerroni, Lorenzo; Mihm, Martin J.; Busam, Klaus J.; Murali, Rajmohan

2016-01-01

Summary Histopathological evaluation of melanocytic tumours usually allows reliable distinction of benign melanocytic naevi from melanoma. More difficult is the histopathological classification of Spitz tumours, a heterogeneous group of tumours composed of large epithelioid or spindle-shaped melanocytes. Spitz tumours are biologically distinct from conventional melanocytic naevi and melanoma, as exemplified by their distinct patterns of genetic aberrations. Whereas conventional naevi and melanoma often harbour BRAF mutations, NRAS mutations, or inactivation of NF1, Spitz tumours show HRAS mutations, inactivation of BAP1 (often combined with BRAF mutations), or genomic rearrangements involving the kinases ALK, ROS1, NTRK1, BRAF, RET, and MET. In Spitz naevi, which lack significant histological atypia, all of these mitogenic driver aberrations trigger rapid cell proliferation, but after an initial growth phase, various tumour suppressive mechanisms stably block further growth. In some tumours, additional genomic aberrations may abrogate various tumour suppressive mechanisms, such as cell-cycle arrest, telomere shortening, or DNA damage response. The melanocytes then start to grow in a less organised fashion, may spread to regional lymph nodes, and are termed atypical Spitz tumours. Upon acquisition of even more aberrations, which often activate additional oncogenic pathways or reduce and alter cell differentiation, the neoplastic cells become entirely malignant and may colonise and take over distant organs (spitzoid melanoma). The sequential acquisition of genomic aberrations suggests that Spitz tumours represent a continuous biological spectrum, rather than a dichotomy of benign versus malignant, and that tumours with ambiguous histological features (atypical Spitz tumours) might be best classified as low-grade melanocytic tumours. The number of genetic aberrations usually correlates with the degree of histological atypia and explains why existing ancillary genetic

Spatio-temporal scaling of channels in braided streams.

Science.gov (United States)

A.G. Hunt; G.E. Grant; V.K. Gupta

2006-01-01

The spatio-temporal scaling relationship for individual channels in braided streams is shown to be identical to the spatio-temporal scaling associated with constant Froude number, e.g., Fr = l. A means to derive this relationship is developed from a new theory of sediment transport. The mechanism by which the Fr = l condition apparently governs the scaling seems to...

Chromosome aberration studies and microdosimetry with radiations of varying quality

International Nuclear Information System (INIS)

Grillmaier, R.E.; Bihy, L.; Menzel, H.G.; Schuhmacher, H.

1978-01-01

To investigate the biological effectivity of complex irradiation fields encountered in radiation protection and high LET radiation therapy and to find meaningful specification of radiation quality closely related to the biological effectivity, correlated chromosome aberration studies and microdosimetric investigations have been carried out using cyclotron produced collimated fast neutrons. Human lymphocytes have been irradiated at different dose levels in the direct beam and in different positions in the penumbra and the rates of acentric fragments and dicentrics have been determined. In identical positions microdosimetric measurements have been performed. The dose relationship of aberration rates after irradiation in the direct beam, the aberration rates observed in the penumbra and the microdosimetric quantities ysub(D), ysub(F) and y* are presented and their relations are discussed. Furthermore the dose relationship of chromosome aberrations induced by 60 Co-γ-rays has been investigated and used to establish the RBE dose relationship of cyclotron neutrons

The interplay between the hippocampus and the amygdala in regulating aberrant hippocampal neurogenesis during protracted abstinence from alcohol dependence

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Chitra D Mandyam

2013-06-01

Full Text Available The development of alcohol dependence involves elevated anxiety, low mood, and increased sensitivity to stress, collectively labeled negative affect. Particularly interesting is the recent accumulating evidence that sensitized extrahypothalamic stress systems (e.g., hyperglutamatergic activity, blunted hypothalamic-pituitary-adrenal [HPA] hormonal levels, altered corticotropin-releasing factor signaling, and altered glucocorticoid receptor signaling in the extended amygdala are evident in withdrawn dependent rats, supporting the hypothesis that pathological neuroadaptations in the extended amygdala contribute to the negative affective state. Notably, hippocampal neurotoxicity observed as aberrant dentate gyrus (DG neurogenesis (neurogenesis is a process where neural stem cells in the adult hippocampal subgranular zone generate DG granule cell neurons and DG neurodegeneration are observed in withdrawn dependent rats. These correlations between withdrawal and aberrant neurogenesis in dependent rats suggest that alterations in the DG could be hypothesized to be due to compromised HPA axis activity and associated hyperglutamatergic activity originating from the basolateral amygdala in withdrawn dependent rats. This review discusses a possible link between the neuroadaptations in the extended amygdala stress systems and the resulting pathological plasticity that could facilitate recruitment of new emotional memory circuits in the hippocampus as a function of aberrant DG neurogenesis.

Assessing the construct validity of aberrant salience

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Kristin Schmidt

2009-12-01

Full Text Available We sought to validate the psychometric properties of a recently developed paradigm that aims to measure salience attribution processes proposed to contribute to positive psychotic symptoms, the Salience Attribution Test (SAT. The “aberrant salience” measure from the SAT showed good face validity in previous results, with elevated scores both in high-schizotypy individuals, and in patients with schizophrenia suffering from delusions. Exploring the construct validity of salience attribution variables derived from the SAT is important, since other factors, including latent inhibition/learned irrelevance, attention, probabilistic reward learning, sensitivity to probability, general cognitive ability and working memory could influence these measures. Fifty healthy participants completed schizotypy scales, the SAT, a learned irrelevance task, and a number of other cognitive tasks tapping into potentially confounding processes. Behavioural measures of interest from each task were entered into a principal components analysis, which yielded a five-factor structure accounting for ~75% percent of the variance in behaviour. Implicit aberrant salience was found to load onto its own factor, which was associated with elevated “Introvertive Anhedonia” schizotypy, replicating our previous finding. Learned irrelevance loaded onto a separate factor, which also included implicit adaptive salience, but was not associated with schizotypy. Explicit adaptive and aberrant salience, along with a measure of probabilistic learning, loaded onto a further factor, though this also did not correlate with schizotypy. These results suggest that the measures of learned irrelevance and implicit adaptive salience might be based on similar underlying processes, which are dissociable both from implicit aberrant salience and explicit measures of salience.

Retrospective Dose Reconstruction for Medical Diagnostic X Ray Workers in China using Stable Chromosome Aberrations

International Nuclear Information System (INIS)

Wang, Q.; Liu, P.; Li, J.; Wang, Q.; Tang, S.; Sun, M.; Wang, L.; Aoyama, T.; Sugahara, T.

1998-01-01

The chromosome rearrangements in medical diagnostic X ray workers were analysed using the G-banding technique and evaluated collectively in accumulated doses. A total of 9102 metaphase spreads from 84 medical diagnostic X ray workers and 17 controls were scored. The results showed that: (1) the frequencies of translocation, stable chromosome aberration and total aberration in X ray workers were significantly higher than those of controls (P < 0.05 γ 0.005), unstable chromosome aberrations (including dicentric and acentric aberration) tended upwards; (2) the main aberration in stable aberrations was reciprocal translocation; (3) the stable aberration predominated strikingly in total aberrations. The medical diagnostic X ray workers were divided into three groups according to calendar year of entry. The data showed that the frequencies of translocation, stable aberration and total aberration increased with earlier year of entry, especially in two groups who started working before 1970. According to the equation recommended by Straume et al, linear coefficient (α) in the linear quadratic model provided by Fernandez's experiment, their collective accumulation doses calculated were 0.53, 0.26 and 0.06 Gy for calendar year of entry before 1960, 1960-1969, and after 1970, in X ray workers, respectively. (author)

A Spatiotemporal Multi-View-Based Learning Method for Short-Term Traffic Forecasting

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Shifen Cheng

2018-06-01

Full Text Available Short-term traffic forecasting plays an important part in intelligent transportation systems. Spatiotemporal k-nearest neighbor models (ST-KNNs have been widely adopted for short-term traffic forecasting in which spatiotemporal matrices are constructed to describe traffic conditions. The performance of the models is closely related to the spatial dependencies, the temporal dependencies, and the interaction of spatiotemporal dependencies. However, these models use distance functions and correlation coefficients to identify spatial neighbors and measure the temporal interaction by only considering the temporal closeness of traffic, which result in existing ST-KNNs that cannot fully reflect the essential features of road traffic. This study proposes an improved spatiotemporal k-nearest neighbor model for short-term traffic forecasting by utilizing a multi-view learning algorithm named MVL-STKNN that fully considers the spatiotemporal dependencies of traffic data. First, the spatial neighbors for each road segment are automatically determined using cross-correlation under different temporal dependencies. Three spatiotemporal views are built on the constructed spatiotemporal closeness, periodic, and trend matrices to represent spatially heterogeneous traffic states. Second, a spatiotemporal weighting matrix is introduced into the ST-KNN model to recognize similar traffic patterns in the three spatiotemporal views. Finally, the results of traffic pattern recognition under these three spatiotemporal views are aggregated by using a neural network algorithm to describe the interaction of spatiotemporal dependencies. Extensive experiments were conducted using real vehicular-speed datasets collected on city roads and expressways. In comparison with baseline methods, the results show that the MVL-STKNN model greatly improves short-term traffic forecasting by lowering the mean absolute percentage error between 28.24% and 46.86% for the city road dataset and

A Mixed Land Cover Spatio-temporal Data Model Based on Object-oriented and Snapshot

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LI Yinchao

2016-07-01

Full Text Available Spatio-temporal data model (STDM is one of the hot topics in the domains of spatio-temporal database and data analysis. There is a common view that a universal STDM is always of high complexity due to the various situation of spatio-temporal data. In this article, a mixed STDM is proposed based on object-oriented and snapshot models for modelling and analyzing landcover change (LCC. This model uses the object-oriented STDM to describe the spatio-temporal processes of land cover patches and organize their spatial and attributive properties. In the meantime, it uses the snapshot STDM to present the spatio-temporal distribution of LCC on the whole via snapshot images. The two types of models are spatially and temporally combined into a mixed version. In addition to presenting the spatio-temporal events themselves, this model could express the transformation events between different classes of spatio-temporal objects. It can be used to create database for historical data of LCC, do spatio-temporal statistics, simulation and data mining with the data. In this article, the LCC data in Heilongjiang province is used for case study to validate spatio-temporal data management and analysis abilities of mixed STDM, including creating database, spatio-temporal query, global evolution analysis and patches spatio-temporal process expression.

Relationship of DNA lesions and their repair to chromosomal aberration production

International Nuclear Information System (INIS)

Bender, M.A.

1979-01-01

Recent work on the roles of specific kinds of DNA lesions and their enzymatic repair systems in the production of chromosomal aberrations seems consistent with a simple molecular model of chromosomal aberrations formation. Evidence from experiments with the human repair-deficient genetic diseases xeroderma pigmentosom, ataxia telangiectasia, and Fanconi's anemia is reviewed in the light of the contributions to aberration production of single and double polynucleotide strand breaks, base damage, polynucleotide strand crosslinks, and pyrimidine cyclobutane dimers

Relationship of DNA lesions and their repair to chromosomal aberration production

Energy Technology Data Exchange (ETDEWEB)

Bender, M.A.

1979-01-01

Recent work on the roles of specific kinds of DNA lesions and their enzymatic repair systems in the production of chromosomal aberrations seems consistent with a simple molecular model of chromosomal aberrations formation. Evidence from experiments with the human repair-deficient genetic diseases xeroderma pigmentosom, ataxia telangiectasia, and Fanconi's anemia is reviewed in the light of the contributions to aberration production of single and double polynucleotide strand breaks, base damage, polynucleotide strand crosslinks, and pyrimidine cyclobutane dimers.

Low chromatic aberration hexapole for molecular state selection

International Nuclear Information System (INIS)

Ke, Yi; Deng, Xiao-Bing; Hu, Zhong-Kun

2016-01-01

In molecular beam state-selection experiments, the electrostatic hexapole acts as an optical lens, imaging molecules from the source to the focus. The molecular longitudinal velocity spread induces the phenomenon of chromatic aberration, which will reduce the state-selection purity. We propose a scheme which can effectively reduce the chromatic aberration by changing the hexapole voltage operating manner. The hexapole is already charged before molecules arrive at the entrance of the hexapole. When molecules are completely inside the hexapole, the voltage is switched off rapidly at an appropriate time. In this manner, faster molecules travel a longer hexapole focusing region than slower molecules. Therefore the focusing positions of molecules with different velocities become close. Numerical trajectory simulations of molecular state selection are carried out, and the results show that this low chromatic aberration hexapole can significantly improve the state purity from 46.2% to 87.0%. (paper)

An electron microscope for the aberration-corrected era

Energy Technology Data Exchange (ETDEWEB)

Krivanek, O.L. [Nion Co., 1102 8th Street, Kirkland, WA 98033 (United States)], E-mail: krivanek.ondrej@gmail.com; Corbin, G.J.; Dellby, N.; Elston, B.F.; Keyse, R.J.; Murfitt, M.F.; Own, C.S.; Szilagyi, Z.S.; Woodruff, J.W. [Nion Co., 1102 8th Street, Kirkland, WA 98033 (United States)

2008-02-15

Improved resolution made possible by aberration correction has greatly increased the demands on the performance of all parts of high-end electron microscopes. In order to meet these demands, we have designed and built an entirely new scanning transmission electron microscope (STEM). The microscope includes a flexible illumination system that allows the properties of its probe to be changed on-the-fly, a third-generation aberration corrector which corrects all geometric aberrations up to fifth order, an ultra-responsive yet stable five-axis sample stage, and a flexible configuration of optimized detectors. The microscope features many innovations, such as a modular column assembled from building blocks that can be stacked in almost any order, in situ storage and cleaning facilities for up to five samples, computer-controlled loading of samples into the column, and self-diagnosing electronics. The microscope construction is described, and examples of its capabilities are shown.

An electron microscope for the aberration-corrected era

International Nuclear Information System (INIS)

Krivanek, O.L.; Corbin, G.J.; Dellby, N.; Elston, B.F.; Keyse, R.J.; Murfitt, M.F.; Own, C.S.; Szilagyi, Z.S.; Woodruff, J.W.

2008-01-01

Improved resolution made possible by aberration correction has greatly increased the demands on the performance of all parts of high-end electron microscopes. In order to meet these demands, we have designed and built an entirely new scanning transmission electron microscope (STEM). The microscope includes a flexible illumination system that allows the properties of its probe to be changed on-the-fly, a third-generation aberration corrector which corrects all geometric aberrations up to fifth order, an ultra-responsive yet stable five-axis sample stage, and a flexible configuration of optimized detectors. The microscope features many innovations, such as a modular column assembled from building blocks that can be stacked in almost any order, in situ storage and cleaning facilities for up to five samples, computer-controlled loading of samples into the column, and self-diagnosing electronics. The microscope construction is described, and examples of its capabilities are shown

γ-ray induced chromosome aberration in rabbit peripheral blood lymphocytes irradiated in partial and whole body and decline of aberration rate with time post-exposure

International Nuclear Information System (INIS)

Zhang Lianzhen; Deng Zhicheng; Wang Haiyan

1997-01-01

Te author presents the results of study on 60 Co γ-ray induced chromosome aberration in rabbits peripheral blood lymphocytes irradiated in partial and whole body and the aberration rate decrease with the time of post-exposure. The experiments included 5 groups, it was whole-body exposure group, partial-body exposure (abdomen and pelvic cavity) group, blood irradiation group in vitro and control group respectively. Radiation dose was 3.0 Gy delivered at rate of 0.5 Gy/min. The results show that it was no significant differences between whole body and in blood irradiation group. The chromosome aberration yield in whole body exposure group was higher than that in partial-body group and in the abdomen exposure group was higher than in that in the pelvic cavity irradiation; The chromosome aberration rate decreased with the time of post-exposure in partial and whole body by γ-ray irradiation

Effects of SMILE and Trans-PRK on corneal higher order aberrations after myopic correction

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Jiao Zhao

2018-02-01

Full Text Available AIM:To observe the effects of small incision lenticule extraction(SMILEand trans-epithelial photorefractive keratectomy(Trans-PRKon corneal horizontal coma, vertical coma, and spherical aberration and total higher order aberrations after refractive correction for myopia. METHODS: This was a prospective non-randomized cohort study. The cohort included 40 patients(80 eyeswith myopia, who received refraction correction surgery from December 2016 to February 2017 in Leshan Ophthalmic Center. Twenty patients(40 eyesreceived SMILE surgery and the other 20 patients(40 eyesreceived Trans-PRK surgery. Corneal aberrations were determined by a high-resolution Pentacam Scheimpflug camera before the surgery and at 1 and 3mo after the operation. Statistical analyses were performed using analysis of variance of repeated measures. RESULTS: At 1 and 3mo post-operation, the uncorrected visual acuity in both groups was better than or equal to the preoperative best corrected visual acuity. The preoperative corneal aberrations showed no significant difference between the two groups(P>0.05. Significantly higher aberration was found after the surgery in both groups(PP>0.05. Post-operation, horizontal and vertical coma had no significant difference between the two groups(P>0.05, while SMILE group showed lower spherical aberration and lower total higher order aberration than Trans-PRK group(PCONCLUSION: Both SMILE and Trans-PRK increase corneal aberration and their effects on horizontal and vertical coma are similar. However, SMILE has a minor influence on spherical aberration and total high order aberration than Trans-PRK.

A stream cipher based on a spatiotemporal chaotic system

International Nuclear Information System (INIS)

Li Ping; Li Zhong; Halang, Wolfgang A.; Chen Guanrong

2007-01-01

A stream cipher based on a spatiotemporal chaotic system is proposed. A one-way coupled map lattice consisting of logistic maps is served as the spatiotemporal chaotic system. Multiple keystreams are generated from the coupled map lattice by using simple algebraic computations, and then are used to encrypt plaintext via bitwise XOR. These make the cipher rather simple and efficient. Numerical investigation shows that the cryptographic properties of the generated keystream are satisfactory. The cipher seems to have higher security, higher efficiency and lower computation expense than the stream cipher based on a spatiotemporal chaotic system proposed recently

Estimation and Compensation of aberrations in Spatial Light Modulators

International Nuclear Information System (INIS)

Arias, Augusto; Castaneda, Roman

2011-01-01

The spatial light modulator (SLM) Holoeye LC-R720 is based on LCoS (Liquid Crystal on Silicon) technology. Due to the induced curvatures on the silicon plate by the production process, there are static aberrations in the wave-fronts modified by the SLM. In order to calculate the aberrated wave-front we used phase-shifting interferometry, an optimization algorithm for far field propagation, and the geometric characterization of the focal spot along the caustic. Zernike polynomials were used for expanding and comparing the wave-fronts. The aberration compensation was carried out by displaying the conjugated transmittance on the SLM. The complexity of the experimental setup and the requirements of the digital processing of each estimation method were comparatively analyzed.

Spatio-temporal Hotelling observer for signal detection from image sequences.

Science.gov (United States)

Caucci, Luca; Barrett, Harrison H; Rodriguez, Jeffrey J

2009-06-22

Detection of signals in noisy images is necessary in many applications, including astronomy and medical imaging. The optimal linear observer for performing a detection task, called the Hotelling observer in the medical literature, can be regarded as a generalization of the familiar prewhitening matched filter. Performance on the detection task is limited by randomness in the image data, which stems from randomness in the object, randomness in the imaging system, and randomness in the detector outputs due to photon and readout noise, and the Hotelling observer accounts for all of these effects in an optimal way. If multiple temporal frames of images are acquired, the resulting data set is a spatio-temporal random process, and the Hotelling observer becomes a spatio-temporal linear operator. This paper discusses the theory of the spatio-temporal Hotelling observer and estimation of the required spatio-temporal covariance matrices. It also presents a parallel implementation of the observer on a cluster of Sony PLAYSTATION 3 gaming consoles. As an example, we consider the use of the spatio-temporal Hotelling observer for exoplanet detection.

Stress Sensitivity, Aberrant Salience, and Threat Anticipation in Early Psychosis: An Experience Sampling Study.

Science.gov (United States)

Reininghaus, Ulrich; Kempton, Matthew J; Valmaggia, Lucia; Craig, Tom K J; Garety, Philippa; Onyejiaka, Adanna; Gayer-Anderson, Charlotte; So, Suzanne H; Hubbard, Kathryn; Beards, Stephanie; Dazzan, Paola; Pariante, Carmine; Mondelli, Valeria; Fisher, Helen L; Mills, John G; Viechtbauer, Wolfgang; McGuire, Philip; van Os, Jim; Murray, Robin M; Wykes, Til; Myin-Germeys, Inez; Morgan, Craig

2016-05-01

While contemporary models of psychosis have proposed a number of putative psychological mechanisms, how these impact on individuals to increase intensity of psychotic experiences in real life, outside the research laboratory, remains unclear. We aimed to investigate whether elevated stress sensitivity, experiences of aberrant novelty and salience, and enhanced anticipation of threat contribute to the development of psychotic experiences in daily life. We used the experience sampling method (ESM) to assess stress, negative affect, aberrant salience, threat anticipation, and psychotic experiences in 51 individuals with first-episode psychosis (FEP), 46 individuals with an at-risk mental state (ARMS) for psychosis, and 53 controls with no personal or family history of psychosis. Linear mixed models were used to account for the multilevel structure of ESM data. In all 3 groups, elevated stress sensitivity, aberrant salience, and enhanced threat anticipation were associated with an increased intensity of psychotic experiences. However, elevated sensitivity to minor stressful events (χ(2)= 6.3,P= 0.044), activities (χ(2)= 6.7,P= 0.036), and areas (χ(2)= 9.4,P= 0.009) and enhanced threat anticipation (χ(2)= 9.3,P= 0.009) were associated with more intense psychotic experiences in FEP individuals than controls. Sensitivity to outsider status (χ(2)= 5.7,P= 0.058) and aberrantly salient experiences (χ(2)= 12.3,P= 0.002) were more strongly associated with psychotic experiences in ARMS individuals than controls. Our findings suggest that stress sensitivity, aberrant salience, and threat anticipation are important psychological processes in the development of psychotic experiences in daily life in the early stages of the disorder. © The Author 2016. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center.

Nodular Hyperplasia Arising from the Lateral Aberrant Thyroid Tissue: A Case Report

International Nuclear Information System (INIS)

Jeong, Min Hye; Park, Jeong Seon; Lee, Young Jun

2012-01-01

The presence of aberrant thyroid tissue in the lateral neck is very rare. In addition, nodular hyperplasia in ectopic thyroid has rarely been reported. Due to the unusual location, the presence of lateral aberrant thyroid tissue could be misdiagnosed as a lymphadenopathy, neurogenic tumor, etc. We report on a case of nodular hyperplasia arising from the right lateral aberrant thyroid tissue.

Optimization of Spatiotemporal Apertures in Channel Sounding

DEFF Research Database (Denmark)

Pedersen, Troels; Pedersen, Claus; Yin, Xuefeng

2008-01-01

a spatiotemporal model which can describe parallel as well as switched sounding systems. The proposed model is applicable for arbitrary layouts of the spatial arrays. To simplify the derivations we investigate the special case of linear spatial arrays. However, the results obtained for linear arrays can......In this paper we investigate the impact of the spatio-temporal aperture of a channel sounding system equipped with antenna arrays at the transmitter and receiver on the accuracy of joint estimation of Doppler frequency and bi-direction. The contribution of this work is three-fold. Firstly, we state...... be generalized to arbitrary arrays. Secondly, we give the necessary and sufficient conditions for a spatio-temporal array to yield the minimum Cramér-Rao lower bound in the single-path case and Bayesian Cramér-Rao Lower Bound in the multipath case. The obtained conditions amount to an orthogonality condition...

Chromosomal aberrations in Cynomolgus peripheral lymphocytes during and after fractionated whole-body γ-irradiation

International Nuclear Information System (INIS)

Guedeney, G.; Malarbet, J.L.; Doloy, M.T.

1989-01-01

Cynomolgus monkeys (Macaca fascicularis) were exposed to fractionated whole-body γ-irradiation at high and low dose rates for 4 or 5 weeks. The time-dependence of chromosomal aberrations was studied in relation to the number of lymphocytes during irradiation and after exposure for periods of up to about 600 days for chromosomal aberrations and 200 days for lymphocyte counts. Additivity of the daily effects on the number of chromosomal aberrations was observed during the exposures. Immediately after the end of the exposures the number of chromosomal aberrations decreased to reach low values. The disappearance of chromosomal aberrations seemed to be related to recovery of the lymphocyte counts. The data presented here emphasize the different kinetic patterns of chromosomal aberrations after fractionated and acute irradiation. (author)

Establishing working standards of chromosome aberrations analysis for biological dosimetry

International Nuclear Information System (INIS)

Bui Thi Kim Luyen; Tran Que; Pham Ngoc Duy; Nguyen Thi Kim Anh; Ha Thi Ngoc Lien

2015-01-01

Biological dosimetry is an dose assessment method using specify bio markers of radiation. IAEA (International Atomic Energy Agency) and ISO (International Organization for Standardization) defined that dicentric chromosome is specify for radiation, it is a gold standard for biodosimetry. Along with the documents published by IAEA, WHO, ISO and OECD, our results of study on the chromosome aberrations induced by radiation were organized systematically in nine standards that dealing with chromosome aberration test and micronucleus test in human peripheral blood lymphocytes in vitro. This standard addresses: the reference dose-effect for dose estimation, the minimum detection levels, cell culture, slide preparation, scoring procedure for chromosome aberrations use for biodosimetry, the criteria for converting aberration frequency into absorbed dose, reporting of results. Following these standards, the automatic analysis devices were calibrated for improving biological dosimetry method. This standard will be used to acquire and maintain accreditation of the Biological Dosimetry laboratory in Nuclear Research Institute. (author)

Low level dose induced chromosome aberrations in human blood lymphocytes

International Nuclear Information System (INIS)

Pohl-Rueling, J.

1992-01-01

Unstable structural aberrations in chromosomes of human blood lymphocytes cannot be used as biological dosemeters in the low dose range, when extrapolating from high doses using a linear dose response, as required by the original formula of the dual radiation action theory. A survey is given of experimental dose-response curves of chromosome aberrations, obtained in investigations not only by this institute, in cooperation with many other laboratories, but also by various authors in different areas of the world. The results are not compatible with the predicted linear dose relationships at in vivo dose ranges up to 30 mGy.y -1 . The aberration frequencies rise sharply with dose within the normal environmental exposure up to about twice that level. At higher doses, aberration frequencies increase less rapidly and reach a plateau. Some in vitro experiments of various authors with higher doses of low LET radiations, up to about 400 mGy have found dose responses with steps. (author)

Induction of chromosomal aberrations in human lymphocytes by fission neutrons

International Nuclear Information System (INIS)

Silva, Marcia Augusta da; Coelho, Paulo Rogerio Pinto; Bartolini, Paolo; Okazaki, Kayo

2009-01-01

Chromosome aberrations induced by sparsely ionizing radiation (low-LET) are well known and cytogenetic analyses of irradiated human lymphocytes have been widely applied to biological dosimetry. However, much less is known about chromosome aberrations induced by densely ionizing radiation (high LET), such as that of alpha particles or neutrons. Such particles induce DNA strand breaks, as well as chromosome breakage and rearrangements of high complexity. This damage is more localized and less efficiently repaired than after X- or γ-ray irradiation. This preferential production of complex aberrations by densely ionizing radiation is related to the unique energy deposition patterns, which produces highly localized multiple DNA damage at the chromosomal level. A better knowledge of the interactions between different types of radiation and cellular DNA is of importance, not only from the radiobiological viewpoint but also for dosimetric and therapeutic purposes. The objective of the present study was to analyse the cytogenetic effects of fission neutrons on peripheral blood lymphocytes in order to evaluate structural and numerical aberrations and number of cells in the different mitotic cycles. So, blood samples from five healthy donors, 22-25 years old, of both sexes, were irradiated in the Research Reactor IEA-R1 of our Institute (IPEN/CNEN-SP) with thermal and fast neutrons at doses of 0.2; 0.3; 0.5 and 1.0 Gy. The γ contribution to the total absorbed dose was about 30%. These doses were monitored by thermoluminescent dosemeters: LiF-600 (for neutrons) and LiF-700 (for γ-rays). The data concerning structural aberrations were evaluated with regard to three parameters: percentage of cells with aberrations, number of aberrations/cell and number of dicentric/cell. The cytogenetic results showed an increase in the three parameters after irradiation with neutrons, as a function of radiation dose. Apparently, there was no influence of neutrons on the kinetics of cellular

Aberrations of chromosome 8 in myelodysplastic syndromes: Clinical and biological significance

Directory of Open Access Journals (Sweden)

Marisavljević Dragomir

2006-01-01

Full Text Available Introduction: Rearrangements of any single chromosome in human karyotype have been reported in patients with pMDS. Objective: To examine the role of aberrations of chromosome 8 in pathogenesis, clinical presentation and progression of myelodysplastic syndromes. Method: Cytogenetic analysis of bone marrow cells was carried out by direct method and by means of 24- and/or 48-hour unstimulated cell culture. Chromosomes were obtained by modified method of HG-bands. Results: On presentation, 109 out of 271 successfully karyotyped patients (40,2% had abnormal karyotypes. Among them, 22 patients (10.9% had aberrations of chromosome 8. Ten patients had trisomy 8 as "simple" aberration whilst additional three cases had trisomy 8 included in "complex" karyotypes (≥3 chromosomes. Cases with constitutional trisomy 8 mosaicism (CT8M were excluded using the chromosome analyses of PHA-stimulated blood cultures. On the contrary, monosomy (seven patients or deletion of chromosome 8 (two patients were exclusively found in "complex" karyotypes. During prolonged cytogenetic follow-up, trisomy 8 was not recorded in evolving karyotypes. In contrast, trisomy 8 disappeared in two cases during subsequent cytogenetic studies, i.e. 23 and 72 months from diagnosis, accompanied in one patient with complete hematological remission. No difference regarding age, sex, cytopenia, blood and marrow blast count or response to treatment was found between patients with trisomy 8 as the sole aberration compared to those with normal cytogenetics. Median survival of patients with trisomy 8 as the sole aberration was 27 months, as compared to 32 months in patients with normal cytogenetics (p=0.468, whilst median survival of patients with aberrations of chromosome 8 included in "complex" karyotypes was only 4 months. Conclusion: Aberrations of chromosome 8 are common in patients with pMDS. The presence of a clone with trisomy 8 is not always the sign of disease progression or poor

Spatiotemporal Diffusive Evolution and Fractal Structure of Ground Motion

Science.gov (United States)

Suwada, Tsuyoshi

2018-02-01

The spatiotemporal diffusive evolution and fractal structure of ground motion have been investigated at the in-ground tunnel of the KEK B-Factory (KEKB) injector linear accelerator (linac). The slow dynamic fluctuating displacements of the tunnel floor are measured in real time with a new remote-controllable sensing system based on a laser-based alignment system. Based on spatiotemporal analyses with linear-regression models, which were applied in both the time and frequency domains to time-series data recorded over a period of approximately 8 months, both coherent and stochastic components in the displacements of the tunnel floor were clearly observed along the entire length of the linac. In particular, it was clearly observed that the stochastic components exhibited characteristic spatiotemporal diffusive evolution with the fractal structure and fractional dimension. This report describes in detail the experimental techniques and analyses of the spatiotemporal diffusive evolution of ground motion observed at the in-ground tunnel of the injector linac using a real-time remote-controllable sensing system.

Intestine-targeted DGAT1 inhibition improves obesity and insulin resistance without skin aberrations in mice.

Directory of Open Access Journals (Sweden)

Naoto Tsuda

Full Text Available OBJECTIVE: Diacylglycerol O-acyltransferase 1 (DGAT1 catalyzes the final committed step in triglyceride biosynthesis. DGAT1 null mice are known to be resistant to diet-induced obesity, and more insulin sensitive relative to the wild-type; however, the mice exhibit abnormalities in the skin. This work determined whether the intestine-targeted DGAT1 inhibitor could improve obesity and insulin resistance without skin aberrations in mice. DESIGN AND METHODS: We synthesized 2 DGAT1 inhibitors: Compound A, described in the patent application from the Japan Tobacco, and Compound B (A-922500, reported by Abbott Laboratories. Both compounds were evaluated for inhibitory activities against DGAT1 enzymes and effects on the skin in mice in vivo. Compound B was further investigated for effects on obesity and insulin resistance in diet-induced-obese (DIO mice. RESULTS: The 2 compounds comparably inhibited the DGAT1 enzyme activity and the cellular triglyceride synthesis in vitro, while they showed different distribution patterns in mice in vivo. Compound A, which distributed systemically, caused skin aberrations, while Compound B, which preferentially distributed to the intestine, improved obesity and insulin resistance without skin aberrations in DIO mice. CONCLUSIONS: Our results suggest that the intestine is the key tissue in which DGAT1 plays a role in promoting obesity and insulin resistance.

Spatiotemporal alterations of cortical network activity by selective loss of NOS-expressing interneurons .

Directory of Open Access Journals (Sweden)

Dan eShlosberg

2012-02-01

Full Text Available Deciphering the role of GABAergic neurons in large neuronal networks such as the neocortex forms a particularly complex task as they comprise a highly diverse population. The neuronal isoform of the enzyme nitric oxide synthase (nNOS is expressed in the neocortex by specific subsets of GABAergic neurons. These neurons can be identified in live brain slices by the nitric oxide (NO fluorescent indicator DAF-2DA. However, this indicator was found to be highly toxic to the stained neurons. We used this feature to induce acute phototoxic damage to NO-producing neurons in cortical slices, and measured subsequent alterations in parameters of cellular and network activity.Neocortical slices were briefly incubated in DAF-2DA and then illuminated through the 4X objective. Histochemistry for NADPH diaphorase, a marker for nNOS activity, revealed elimination of staining in the illuminated areas following treatment. Whole cell recordings from several neuronal types before, during and after illumination confirmed the selective damage to non fast-spiking interneurons. Treated slices displayed mild disinhibition. The reversal potential of compound synaptic events on pyramidal neurons became more positive, and their decay time constant was elongated, substantiating the removal of an inhibitory conductance. The horizontal decay of local field potentials (LFPs was significantly reduced at distances of 300-400 m from the stimulation, but not when inhibition was non-selectively weakened with the GABAA blocker picrotoxin. Finally, whereas the depression of LFPs along short trains of 40 Hz stimuli was linearly reduced with distance or initial amplitude in control slices, this ordered relationship was disrupted in DAF-treated slices. These results reveal that NO-producing interneurons in the neocortex convey lateral inhibition to neighboring columns, and shape the spatiotemporal dynamics of the network's activity.

Spatiotemporal alterations of cortical network activity by selective loss of NOS-expressing interneurons.

Science.gov (United States)

Shlosberg, Dan; Buskila, Yossi; Abu-Ghanem, Yasmin; Amitai, Yael

2012-01-01

Deciphering the role of GABAergic neurons in large neuronal networks such as the neocortex forms a particularly complex task as they comprise a highly diverse population. The neuronal isoform of the enzyme nitric oxide synthase (nNOS) is expressed in the neocortex by specific subsets of GABAergic neurons. These neurons can be identified in live brain slices by the nitric oxide (NO) fluorescent indicator diaminofluorescein-2 diacetate (DAF-2DA). However, this indicator was found to be highly toxic to the stained neurons. We used this feature to induce acute phototoxic damage to NO-producing neurons in cortical slices, and measured subsequent alterations in parameters of cellular and network activity. Neocortical slices were briefly incubated in DAF-2DA and then illuminated through the 4× objective. Histochemistry for NADPH-diaphorase (NADPH-d), a marker for nNOS activity, revealed elimination of staining in the illuminated areas following treatment. Whole cell recordings from several neuronal types before, during, and after illumination confirmed the selective damage to non-fast-spiking (FS) interneurons. Treated slices displayed mild disinhibition. The reversal potential of compound synaptic events on pyramidal neurons became more positive, and their decay time constant was elongated, substantiating the removal of an inhibitory conductance. The horizontal decay of local field potentials (LFPs) was significantly reduced at distances of 300-400 μm from the stimulation, but not when inhibition was non-selectively weakened with the GABA(A) blocker picrotoxin. Finally, whereas the depression of LFPs along short trains of 40 Hz stimuli was linearly reduced with distance or initial amplitude in control slices, this ordered relationship was disrupted in DAF-treated slices. These results reveal that NO-producing interneurons in the neocortex convey lateral inhibition to neighboring columns, and shape the spatiotemporal dynamics of the network's activity.

Corneal Aberrations in Former Preterm Infants: Results From The Wiesbaden Prematurity Study.

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Fieß, Achim; Schuster, Alexander K; Kölb-Keerl, Ruth; Knuf, Markus; Kirchhof, Bernd; Muether, Philipp S; Bauer, Jacqueline

2017-12-01

To compare corneal aberrations in former preterm infants to that of full-term infants. A prospective cross-sectional study was carried out measuring the corneal shape with Scheimpflug imaging in former preterm infants of gestational age (GA) ≤32 weeks and full-term infants with GA ≥37 weeks now being aged between 4 to 10 years. The main outcome measures were corneal aberrations including astigmatism (Zernike: Z2-2; Z22), coma (Z3-1; Z31), trefoil (Z3-3; Z33), spherical aberration (Z40) and root-mean square of higher-order aberrations (RMS HOA). Multivariable analysis was performed to assess independent associations of gestational age groups and of retinopathy of prematurity (ROP) occurrence with corneal aberrations adjusting for sex and age at examination. A total of 259 former full-term and 226 preterm infants with a mean age of 7.2 ± 2.0 years were included in this study. Statistical analysis revealed an association of extreme prematurity (GA ≤28 weeks) with higher-order and lower-order aberrations of the total cornea. Vertical coma was higher in extreme prematurity (P prematurity rather than with ROP occurrence.

Measurement of specimen-induced aberrations of biological samples using phase stepping interferometry.

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Schwertner, M; Booth, M J; Neil, M A A; Wilson, T

2004-01-01

Confocal or multiphoton microscopes, which deliver optical sections and three-dimensional (3D) images of thick specimens, are widely used in biology. These techniques, however, are sensitive to aberrations that may originate from the refractive index structure of the specimen itself. The aberrations cause reduced signal intensity and the 3D resolution of the instrument is compromised. It has been suggested to correct for aberrations in confocal microscopes using adaptive optics. In order to define the design specifications for such adaptive optics systems, one has to know the amount of aberrations present for typical applications such as with biological samples. We have built a phase stepping interferometer microscope that directly measures the aberration of the wavefront. The modal content of the wavefront is extracted by employing Zernike mode decomposition. Results for typical biological specimens are presented. It was found for all samples investigated that higher order Zernike modes give only a small contribution to the overall aberration. Therefore, these higher order modes can be neglected in future adaptive optics sensing and correction schemes implemented into confocal or multiphoton microscopes, leading to more efficient designs.

Effects of long-term radiation exposure on chromosomal aberrations in radiological technologists

International Nuclear Information System (INIS)

Kumagai, Etsuko; Onomichi, Mitsukazu; Tanaka, Ryuji; Kumagai, Takashi; Sawada, Shozo.

1990-01-01

Chromosomal aberrations in the lymphocytes of radiation technologists (RT) were analyzed by the trypsin G-banding method to study the late effects of long-term exposure to low doses of radiation. Structural aberrations were identified in 384 (2.5%) of 15442 cells analyzed from 53 RT as compared to 177 (1.6%) of 11136 cells from 36 healthy controls. Stable aberrations were the most frequent in both groups and were either translocations or deletions. Unstable aberrations were mainly acentric fragments in both groups. The frequency of translocations and acentric fragments was significantly higher in the RT than in the controls and was highest in the RT over 50 years. The highest frequency observed in the >50 age group was attributed to the unknown for cumulative dose prior to introduction of film badges. Frequency of chromosomal aberrations correlated with the estimated dose from the film badges and years of experience of each RT based on the equation y=0.22+0.37D+4.35D 2 , where y is overall frequency of chromosomal aberrations and D is the estimated radiation dose in Sv. (author)

Indeterminacy and Spatiotemporal Data

DEFF Research Database (Denmark)

Pfoser, D.; Tryfona, N.; Jensen, Christian Søndergaard

2005-01-01

For some spatiotemporal applications, it can be assumed that the modeled world is precise and bounded, and that our record of it is precise. While these simplifying assumptions are sufficient in applications like a land information system, they are unnecessarily crude for many other applications...

Aberration analysis for freeform surface terms overlay on general decentered and tilted optical surfaces.

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Yang, Tong; Cheng, Dewen; Wang, Yongtian

2018-03-19

Aberration theory helps designers to better understand the nature of imaging systems. However, the existing aberration theory of freeform surfaces has many limitations. For example, it only works in the special case when the central area of the freeform surface is used. In addition, the light footprint is limited to a circle, which does not match the case of an elliptical footprint for general systems. In this paper, aberrations generated by freeform surface term overlay on general decentered and tilted optical surfaces are analyzed. For the case when the off-axis section of a freeform surface is used, the aberration equation for using stop and nonstop surfaces is discussed, and the aberrations generated by Zernike terms up to Z 17/18 are analyzed in detail. To solve the problem of the elliptical light footprint for tilted freeform surfaces, the scaled pupil vector is used in the aberration analysis. The mechanism of aberration transformation is discovered, and the aberrations generated by different Zernike terms in this case are calculated. Finally we proposed aberration equations for freeform terms on general decentered and tilted freeform surfaces. The research result given in this paper offers an important reference for optical designers and engineers, and it is of great importance in developing analytical methods for general freeform system design, tolerance analysis, and system assembly.

The role of ethnic identity, self-concept, and aberrant salience in psychotic-like experiences.

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Cicero, David C; Cohn, Jonathan R

2018-01-01

Social-cognitive models of psychosis suggest that aberrant salience and self-concept clarity are related to the development and maintenance of psychoticlike experiences (PLEs). People with high aberrant salience but low self-concept clarity tend to have the highest levels of PLEs. Ethnic identity may also be related to PLEs. The current research aimed to (a) replicate the interaction between aberrant salience and self-concept clarity in their association with PLEs in an ethnically diverse sample, (b) examine whether ethnic identity and aberrant salience interact in their association with PLEs, and (c) determine if self-concept clarity and ethnic identity independently interact with aberrant salience in their association with PLEs. An ethnically diverse group of undergraduates (n = 663) completed self-report measures of aberrant salience, self-concept clarity, ethnic identity, and PLEs. There was an interaction between aberrant salience and self-concept clarity such that people with high levels of aberrant salience and low levels of self-concept clarity had the highest levels of PLEs. Similarly, there was an interaction between aberrant salience and ethnic identity such that people with high aberrant salience but low ethnic identity had the highest PLEs. These interactions independently contributed to explaining variance in PLEs. This interaction was present for the Exploration but not Commitment subscales of ethnic identity. These results suggest that, in addition to low self-concept clarity, low ethnic identity may be a risk factor for the development of psychosis. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Do DNA double-strand breaks induced by Alu I lead to development of novel aberrations in the second and third post-treatment mitoses?

International Nuclear Information System (INIS)

Wojcik, A.; Bonk, K.; Mueller, M.U.; Streffer, C.; Obe, G.

1996-01-01

Several authors have reported that ionizing radiation can give rise to novel aberrations several mitotic divisions after the exposure. At our institute this phenomenon has been observed in mouse preimplantation embryos. This cell system is uniquely well suited for such investigations because the first three cell divisions show a high degree of synchrony. Thus the expression of chromosomal aberrations at the first, second and third mitosis after irradiation can be scored unambiguously. To investigate whether DNA double-strand breaks may be the lesions responsible for the delayed expression of chromosomal aberrations, we have studied the frequencies of aberrations in the first, second and third mitosis after treatment of one-cell mouse embryos with the restriction enzyme Alu I. Embryos were permeabilized with Streptolysin-O. The results indicate that the induction of double-strand breaks does not lead to novel aberrations in the third post-treatment mitosis. Several embryos scored at the second mitosis showed very high numbers of aberrations, indicating that Alu I may remain active in the cells for a period of one cell cycle. After treatment with Streptolysin-O alone, enhanced aberration frequencies were observed in the third post-treatment mitosis, suggesting that membrane damage has a delayed effect on the cellular integrity. 44 refs., 3 figs., 3 tabs

Hartmann characterization of the PEEM-3 aberration-corrected X-ray photoemission electron microscope.

Science.gov (United States)

Scholl, A; Marcus, M A; Doran, A; Nasiatka, J R; Young, A T; MacDowell, A A; Streubel, R; Kent, N; Feng, J; Wan, W; Padmore, H A

2018-05-01

Aberration correction by an electron mirror dramatically improves the spatial resolution and transmission of photoemission electron microscopes. We will review the performance of the recently installed aberration corrector of the X-ray Photoemission Electron Microscope PEEM-3 and show a large improvement in the efficiency of the electron optics. Hartmann testing is introduced as a quantitative method to measure the geometrical aberrations of a cathode lens electron microscope. We find that aberration correction leads to an order of magnitude reduction of the spherical aberrations, suggesting that a spatial resolution of below 100 nm is possible at 100% transmission of the optics when using x-rays. We demonstrate this improved performance by imaging test patterns employing element and magnetic contrast. Published by Elsevier B.V.

Circumflex coronary artery with aberrant origin and atherosclerosis

International Nuclear Information System (INIS)

Ozcan, E.; Bozlar, U.; Celik, T.; Tasar, M.

2012-01-01

Full text: Introduction: Circumflex (Cx) coronary artery congenital anomaly is reported to be less than 1% incidence. Coronary arteries with aberrant origin are more likely to have atherosclerosis according to some published literatures. Objectives and tasks: In this study we aim to present computed tomography (CT) angiography findings of a patient, who has Cx artery with aberrant origin and atherosclerotic. Materials and methods: 57-year-old woman without any symptoms who has risk factors to atherosclerosis was referred to our clinic for coronary CT angiography. Results: In CT angiography; we detected Cx coronary artery with aberrant origin (right sinus of valsalva) and retroaortic course. Also we saw intimal irregularities and calcified plaque causing severe narrowing in the proximal segment of artery. Right coronary and left anterior descendant arteries had mild atherosclerosis. Conclusion: Coroner CT angiography, which allows multiplanar imaging with high resolution, is an effective diagnostic tool for coronary artery disease, like not only congenital anomalies but also acquired atherosclerotic disease

Spherical aberration correction with threefold symmetric line currents.

Science.gov (United States)

Hoque, Shahedul; Ito, Hiroyuki; Nishi, Ryuji; Takaoka, Akio; Munro, Eric

2016-02-01

It has been shown that N-fold symmetric line current (henceforth denoted as N-SYLC) produces 2N-pole magnetic fields. In this paper, a threefold symmetric line current (N3-SYLC in short) is proposed for correcting 3rd order spherical aberration of round lenses. N3-SYLC can be realized without using magnetic materials, which makes it free of the problems of hysteresis, inhomogeneity and saturation. We investigate theoretically the basic properties of an N3-SYLC configuration which can in principle be realized by simple wires. By optimizing the parameters of a system with beam energy of 5.5keV, the required excitation current for correcting 3rd order spherical aberration coefficient of 400 mm is less than 1AT, and the residual higher order aberrations can be kept sufficiently small to obtain beam size of less than 1 nm for initial slopes up to 5 mrad. Copyright © 2015 Elsevier B.V. All rights reserved.

Aberrant PO2 values in proficiency testing.

Science.gov (United States)

Fonzi, C E; Clausen, J L; Mahoney, J

1993-03-01

We prospectively determined the frequency of aberrant vials of fluorocarbon/buffer used for proficiency testing of measurements of pH, PCO2, and PO2, using 20 duplicate vials from 12 lots of fluorocarbon/buffer and two arterial blood gas analyzers in eight reference laboratories. We defined aberrant vials as vials for which both duplicate measurements differed from the mean value of repeated measurements for the specific instrument (for each lot of testing materials) by > 0.04 for pH, > 10% of the mean or 3.0 mm Hg, whichever was greater, for PCO2; or > 10% of the mean or 6 mm Hg, whichever was greater, for PO2. Four of 1620 vials (0.25%) were aberrant, all based on PO2 measurements (range of mean values: pH, 7.181-7.631; PCO2, 12.7-65.9; PO2, 32.5-150.1) were 0.0055 for pH, 0.67 mm Hg for PCO2, and 1.65 mm Hg for PO2. Deliberate contamination of the fluorocarbon emulsion with room air, as might occur during sampling from the vial, indicated that only minor increases in PO2 (e.g., 1.0 mm Hg at PO2 of 56 mm Hg) occur when samples are aspirated. Larger increases in PO2 (mean 7.1 mm Hg at a PO2 of 66 mm Hg) occurred when the syringe samples were contaminated with room air. We conclude that isolated aberrant measurements of PO2 in blood gas proficiency testing attributable to vial contents can occur, but the frequency is very low.

Chromosome aberrations analysis of Serbia population from 1985 to 1995

International Nuclear Information System (INIS)

Jovicic, D.; Markovic, B.; Milacic, S.; Joksic, G.

1996-01-01

After the accident of NE Chernobyl in May 1986, Chernobyl's fallout with unhomogeneous dispersion of radioactive material in atmosphere caused the difference in contamination of the Serbia territory. The highest contamination was found to be in region Uzice, and the lowest in the region Nis. Two groups of population from these regions were undergone chromosome aberration analysis during 1987, 1988 and 1989. year. The results of our examination show increased frequency of structural chromosome aberrations/dicentrics, rings, peri centric inversions and acentric/ in the Uzice population, especially in the 1987. year. In 1985 and 1995 year have not been found chromosome aberrations. 2 refs.; 1 figs.; 2 tabs

Aberrant phenotypes in peripheral T cell lymphomas.

Science.gov (United States)

Hastrup, N; Ralfkiaer, E; Pallesen, G

1989-01-01

Seventy six peripheral T cell lymphomas were examined immunohistologically to test their reactivity with a panel of monoclonal antibodies against 11 T cell associated antigens (CD1-8, CD27, UCHL1, and the T cell antigen receptor). Sixty two (82%) lymphomas showed aberrant phenotypes, and four main categories were distinguished as follows: (i) lack of one or several pan-T cell antigens (49, 64% of the cases); (ii) loss of both the CD4 and CD8 antigens (11, 15% of the cases); (iii) coexpression of the CD4 and CD8 antigens (13, 17% of the cases); and (iv) expression of the CD1 antigen (eight, 11% of the cases). No correlation was seen between the occurrence of aberrant phenotypes and the histological subtype. It is concluded that the demonstration of an aberrant phenotype is a valuable supplement to histological assessment in the diagnosis of peripheral T cell lymphomas. It is recommended that the panel of monoclonal antibodies against T cell differentiation antigens should be fairly large, as apparently any antigen may be lost in the process of malignant transformation. Images Figure PMID:2469701

How and why do toxic conformers of aberrant proteins accumulate during ageing?

Science.gov (United States)

Josefson, Rebecca; Andersson, Rebecca; Nyström, Thomas

2017-07-15

Ageing can be defined as a gradual decline in cellular and physical functions accompanied by an increased sensitivity to the environment and risk of death. The increased risk of mortality is causally connected to a gradual, intracellular accumulation of so-called ageing factors, of which damaged and aggregated proteins are believed to be one. Such aggregated proteins also contribute to several age-related neurodegenerative disorders e.g. Alzheimer's, Parkinson's, and Huntington's diseases, highlighting the importance of protein quality control (PQC) in ageing and its associated diseases. PQC consists of two interrelated systems: the temporal control system aimed at refolding, repairing, and/or removing aberrant proteins and their aggregates and the spatial control system aimed at harnessing the potential toxicity of aberrant proteins by sequestering them at specific cellular locations. The accumulation of toxic conformers of aberrant proteins during ageing is often declared to be a consequence of an incapacitated temporal PQC system-i.e. a gradual decline in the activity of chaperones and proteases. Here, we review the current knowledge on PQC in relation to ageing and highlight that the breakdown of both temporal and spatial PQC may contribute to ageing and thus comprise potential targets for therapeutic interventions of the ageing process. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

The Role of Aberrant Salience and Self-Concept Clarity in Psychotic-Like Experiences

Science.gov (United States)

Cicero, David C.; Becker, Theresa M.; Martin, Elizabeth A.; Docherty, Anna R.; Kerns, John G.

2013-01-01

Most theories of psychotic-like experiences posit the involvement of social-cognitive mechanisms. The current research examined the relations between psychotic-like experiences and two social-cognitive mechanisms, high aberrant salience and low self-concept clarity. In particular, we examined whether aberrant salience, or the incorrect assignment of importance to neutral stimuli, and low self-concept clarity interacted to predict psychotic-like experiences. The current research included three large samples (n = 667, 724, 744) of participants and over-sampled for increased schizotypal personality traits. In all three studies, an interaction between aberrant salience and self-concept clarity was found such that participants with high aberrant salience and low self-concept clarity had the highest levels of psychotic-like experiences. In addition, aberrant salience and self-concept clarity interacted to predict a supplemental measure of delusions in Study 2. In Study 3, in contrast to low self-concept clarity, neuroticism did not interact with aberrant salience to predict psychotic-like experiences, suggesting that the relation between low self-concept clarity and psychosis may not be due to neuroticism. Additionally, aberrant salience and self-concept clarity did not interact to predict to other schizotypal personality disorder criteria, social anhedonia or trait paranoia, which suggests the interaction is specific to psychotic-like experiences. Overall, our results are consistent with several social-cognitive models of psychosis suggesting that aberrant salience and self-concept clarity might be important mechanisms in the occurrence of psychotic-like symptoms. PMID:22452775

Effective and efficient analysis of spatio-temporal data

Science.gov (United States)

Zhang, Zhongnan

Spatio-temporal data mining, i.e., mining knowledge from large amount of spatio-temporal data, is a highly demanding field because huge amounts of spatio-temporal data have been collected in various applications, ranging from remote sensing, to geographical information systems (GIS), computer cartography, environmental assessment and planning, etc. The collection data far exceeded human's ability to analyze which make it crucial to develop analysis tools. Recent studies on data mining have extended to the scope of data mining from relational and transactional datasets to spatial and temporal datasets. Among the various forms of spatio-temporal data, remote sensing images play an important role, due to the growing wide-spreading of outer space satellites. In this dissertation, we proposed two approaches to analyze the remote sensing data. The first one is about applying association rules mining onto images processing. Each image was divided into a number of image blocks. We built a spatial relationship for these blocks during the dividing process. This made a large number of images into a spatio-temporal dataset since each image was shot in time-series. The second one implemented co-occurrence patterns discovery from these images. The generated patterns represent subsets of spatial features that are located together in space and time. A weather analysis is composed of individual analysis of several meteorological variables. These variables include temperature, pressure, dew point, wind, clouds, visibility and so on. Local-scale models provide detailed analysis and forecasts of meteorological phenomena ranging from a few kilometers to about 100 kilometers in size. When some of above meteorological variables have some special change tendency, some kind of severe weather will happen in most cases. Using the discovery of association rules, we found that some special meteorological variables' changing has tight relation with some severe weather situation that will happen

Aberrant repair and fibrosis development in skeletal muscle

Directory of Open Access Journals (Sweden)

Mann Christopher J

2011-05-01

Full Text Available Abstract The repair process of damaged tissue involves the coordinated activities of several cell types in response to local and systemic signals. Following acute tissue injury, infiltrating inflammatory cells and resident stem cells orchestrate their activities to restore tissue homeostasis. However, during chronic tissue damage, such as in muscular dystrophies, the inflammatory-cell infiltration and fibroblast activation persists, while the reparative capacity of stem cells (satellite cells is attenuated. Abnormal dystrophic muscle repair and its end stage, fibrosis, represent the final common pathway of virtually all chronic neurodegenerative muscular diseases. As our understanding of the pathogenesis of muscle fibrosis has progressed, it has become evident that the muscle provides a useful model for the regulation of tissue repair by the local microenvironment, showing interplay among muscle-specific stem cells, inflammatory cells, fibroblasts and extracellular matrix components of the mammalian wound-healing response. This article reviews the emerging findings of the mechanisms that underlie normal versus aberrant muscle-tissue repair.

Primary chromatic aberration elimination via optimization work with genetic algorithm

Science.gov (United States)

Wu, Bo-Wen; Liu, Tung-Kuan; Fang, Yi-Chin; Chou, Jyh-Horng; Tsai, Hsien-Lin; Chang, En-Hao

2008-09-01

Chromatic Aberration plays a part in modern optical systems, especially in digitalized and smart optical systems. Much effort has been devoted to eliminating specific chromatic aberration in order to match the demand for advanced digitalized optical products. Basically, the elimination of axial chromatic and lateral color aberration of an optical lens and system depends on the selection of optical glass. According to reports from glass companies all over the world, the number of various newly developed optical glasses in the market exceeds three hundred. However, due to the complexity of a practical optical system, optical designers have so far had difficulty in finding the right solution to eliminate small axial and lateral chromatic aberration except by the Damped Least Squares (DLS) method, which is limited in so far as the DLS method has not yet managed to find a better optical system configuration. In the present research, genetic algorithms are used to replace traditional DLS so as to eliminate axial and lateral chromatic, by combining the theories of geometric optics in Tessar type lenses and a technique involving Binary/Real Encoding, Multiple Dynamic Crossover and Random Gene Mutation to find a much better configuration for optical glasses. By implementing the algorithms outlined in this paper, satisfactory results can be achieved in eliminating axial and lateral color aberration.

Targeting Aberrant p70S6K Activation for Estrogen Receptor-Negative Breast Cancer Prevention.

Science.gov (United States)

Wang, Xiao; Yao, Jun; Wang, Jinyang; Zhang, Qingling; Brady, Samuel W; Arun, Banu; Seewaldt, Victoria L; Yu, Dihua

2017-11-01

The prevention of estrogen receptor-negative (ER-) breast cancer remains a major challenge in the cancer prevention field, although antiestrogen and aromatase inhibitors have shown adequate efficacy in preventing estrogen receptor-positive (ER + ) breast cancer. Lack of commonly expressed, druggable targets is a major obstacle for meeting this challenge. Previously, we detected the activation of Akt signaling pathway in atypical hyperplasic early-stage lesions of patients. In the current study, we found that Akt and the downstream 70 kDa ribosomal protein S6 kinase (p70S6K) signaling pathway was highly activated in ER - premalignant breast lesions and ER - breast cancer. In addition, p70S6K activation induced transformation of ER - human mammary epithelial cells (hMEC). Therefore, we explored the potential of targeting Akt/p70S6K in the p70S6K activated, ER - hMEC models and mouse mammary tumor models for the prevention of ER - breast cancer. We found that a clinically applicable Akt/p70S6K dual inhibitor, LY2780301, drastically decreased proliferation of hMECs with ErbB2-induced p70S6K activation via Cyclin B1 inhibition and cell-cycle blockade at G 0 -G 1 phase, while it did not significantly reverse the abnormal acinar morphology of these hMECs. In addition, a brief treatment of LY2780301 in MMTV- neu mice that developed atypical hyperplasia (ADH) and mammary intraepithelial neoplasia (MIN) lesions with activated p70S6K was sufficient to suppress S6 phosphorylation and decrease cell proliferation in hyperplasic MECs. In summary, targeting the aberrant Akt/p70S6K activation in ER - hMEC models in vitro and in the MMTV- neu transgenic mouse model in vivo effectively inhibited Akt/S6K signaling and reduced proliferation of hMECs in vitro and ADH/MIN lesions in vivo , indicating its potential in prevention of p70S6K activated ER - breast cancer. Cancer Prev Res; 10(11); 641-50. ©2017 AACR . ©2017 American Association for Cancer Research.

Electron-beam-induced-current and active secondary-electron voltage-contrast with aberration-corrected electron probes

Energy Technology Data Exchange (ETDEWEB)

Han, Myung-Geun, E-mail: mghan@bnl.gov [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Garlow, Joseph A. [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Materials Science and Engineering Department, Stony Brook University, Stony Brook, NY 11794 (United States); Marshall, Matthew S.J.; Tiano, Amanda L. [Department of Chemistry, Stony Brook University, Stony Brook, NY 11974 (United States); Wong, Stanislaus S. [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Department of Chemistry, Stony Brook University, Stony Brook, NY 11974 (United States); Cheong, Sang-Wook [Department of Physics and Astronomy, Rutgers Center for Emergent Materials, Rutgers University, Piscataway, NJ 08854 (United States); Walker, Frederick J.; Ahn, Charles H. [Department of Applied Physics and Center for Research on Interface Structures and Phenomena, Yale University, New Haven, CT 06520 (United States); Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06520 (United States); Zhu, Yimei [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States)

2017-05-15

Highlights: • Electron-beam-induced-current (EBIC) and active secondary-electron voltage-contrast (SE-VC) are demonstrated in STEM mode combined with in situ electrical biasing in a TEM. • Electrostatic potential maps in ferroelectric thin films, multiferroic nanowires, and single crystals obtained by off-axis electron holography were compared with EBIC and SE-VC data. • Simultaneous EBIC and active SE-VC performed with atomic resolution STEM are demonstrated. - Abstract: The ability to map out electrostatic potentials in materials is critical for the development and the design of nanoscale electronic and spintronic devices in modern industry. Electron holography has been an important tool for revealing electric and magnetic field distributions in microelectronics and magnetic-based memory devices, however, its utility is hindered by several practical constraints, such as charging artifacts and limitations in sensitivity and in field of view. In this article, we report electron-beam-induced-current (EBIC) and secondary-electron voltage-contrast (SE-VC) with an aberration-corrected electron probe in a transmission electron microscope (TEM), as complementary techniques to electron holography, to measure electric fields and surface potentials, respectively. These two techniques were applied to ferroelectric thin films, multiferroic nanowires, and single crystals. Electrostatic potential maps obtained by off-axis electron holography were compared with EBIC and SE-VC to show that these techniques can be used as a complementary approach to validate quantitative results obtained from electron holography analysis.

Dynamical topology and statistical properties of spatiotemporal chaos.

Science.gov (United States)

Zhuang, Quntao; Gao, Xun; Ouyang, Qi; Wang, Hongli

2012-12-01

For spatiotemporal chaos described by partial differential equations, there are generally locations where the dynamical variable achieves its local extremum or where the time partial derivative of the variable vanishes instantaneously. To a large extent, the location and movement of these topologically special points determine the qualitative structure of the disordered states. We analyze numerically statistical properties of the topologically special points in one-dimensional spatiotemporal chaos. The probability distribution functions for the number of point, the lifespan, and the distance covered during their lifetime are obtained from numerical simulations. Mathematically, we establish a probabilistic model to describe the dynamics of these topologically special points. In spite of the different definitions in different spatiotemporal chaos, the dynamics of these special points can be described in a uniform approach.

Ionizing radiation and frequency of chromosomal aberrations in exposed personnel

International Nuclear Information System (INIS)

Spasojevic-Tisma, Vera; Pavlovic, Snezana

2008-01-01

Full text: Frequencies of chromosomal aberrations in lymphocytes of peripheral blood were investigated among the observed groups of subjects who were exposed to low radiation doses (external exposure) in comparison with the control group. The first group of subjects is involved in the production of radioisotope technetium, whose accumulated work exposure time ranges between 3 and 30 years. The second group works on inspection of the medical X-ray equipment, whose accumulated work exposure time is between 2 and 34 years. The third group worked on decontamination of the terrain from depleted uranium radioactive ammunition. These workers were involved in mechanical removal of the surface soil layer to a depth of 50 cm. They were selected out of a group of professionals otherwise exposed to radiation from confined sources in their daily work. The accumulated work exposure of this group ranged from 2 to 34 years. The control group consisted of individuals not working in the ionizing radiation zone. The average yearly absorbed dose measured by TL dosimeters for all three observed groups did not exceed 2 mSv. The chromosomal aberrations were analyzed by a modified Moorhead method. The objective of the study was to establish the existence of differences in the frequencies of chromosomal aberrations change with respect to the source type, i.e. type of radioactive emission. Comparisons of the chromosomal changes in the observed groups revealed that the group working on technetium production had an increase in the frequency of chromosomal aberrations with respect to control. The aberrations found were of the acentric fragment and chromosomal break types. A comparison of the exposed groups between each other, no statistically significant differences in the numbers of chromosomal aberrations were found. Soil decontamination from depleted uranium did not contribute to the relative radiation risk, since it lasted only a few months, and was done by the professionals fully clothed

Chromosome aberrations in cultured skin cells obtained from atomic bomb survivors

International Nuclear Information System (INIS)

Honda, Takeo; Sadamori, Naoki.

1989-01-01

Skin specimens were obtained from 11 A-bomb survivors, 10 of whom had been exposed at ≤2300 m from the hypocenter, and 7 non-exposed controls. There was a higher frequency (12%, 147/1222 cells) of chromosome aberrations in the exposed group compared with 1.2% (4/341 cells) in the control group. This suggests that aberrant cells are still present in the skin tissue 40 years or more after the bombing. Of 147 cells, 136 cells (91.3%) showed translocation of chromosome. Other aberrations, such as inversion, deletion, dicentric chromosome and acentric fragment, were observed in only 3.8%. These aberrant cells tended to be observed in A-bomb survivors exposed to high doses and with a history of severe acute symptoms. One hundred and twenty two (83%) of 136 aberrant cells were obtained from 3 A-bomb survivors, which has important implications for marked proliferation of specific clone cells. In an analysis by B-band staining technique for the 122 cells, band sites of break point were found to correspond to loci of protooncogenes, suggesting the involvement in aggressive proliferation of clone cells. (Namekawa, K)

Aberrant Recapitulation of Developmental Program: Novel Target in Scleroderma

Science.gov (United States)

2015-12-01

AWARD NUMBER: W81XWH-12-1-0472 TITLE: “Aberrant Recapitulation of Developmental Program: Novel Target in Scleroderma ” PRINCIPAL INVESTIGATOR...SUBTITLE Aberrant Recapitulation of Developmental Program: Novel Target in Scleroderma 5a. CONTRACT NUMBER W81XWH-12-1-0472 5b. GRANT NUMBER 5c. PROGRAM...SPONSOR/MONITOR’S REPORT NUMBER(S) 12. DISTRIBUTION / AVAILABILITY STATEMENT 13. SUPPLEMENTARY NOTES 14. ABSTRACT Fibrosis in scleroderma is associated

Spherical aberration of an optical system and its influence on depth of focus.

Science.gov (United States)

Mikš, Antonín; Pokorný, Petr

2017-06-10

This paper analyzes the influence of spherical aberration on the depth of focus of symmetrical optical systems for imaging of axial points. A calculation of a beam's caustics is discussed using ray equations in the image plane and considering longitudinal spherical aberration as well. Concurrently, the influence of aberration coefficients on extremes of such a curve is presented. Afterwards, conditions for aberration coefficients are derived if the Strehl definition should be the same in two symmetrically placed planes with respect to the paraxial image plane. Such conditions for optical systems with large aberrations are derived with the use of geometric-optical approximation where the gyration diameter of the beam in given planes of the optical system is evaluated. Therefore, one can calculate aberration coefficients in such a way that the optical system generates a beam of rays that has the gyration radius in a given interval smaller than the defined limit value. Moreover, one can calculate the maximal depth of focus of the optical system respecting the aforementioned conditions.

Outline of an ultracorrector compensating for all primary chromatic and geometrical aberrations of charged-particle lenses

International Nuclear Information System (INIS)

Rose, Harald

2004-01-01

A novel ultracorrector is outlined which compensates for the primary and secondary first-order chromatic aberrations and all third-order geometrical aberrations of electron optical systems with a straight axis. Owing to the imposed symmetry conditions on the fields and the paraxial fundamental rays, the corrector does not introduce aberrations with 2-fold symmetry. The chromatic aberrations are corrected by means of crossed electric magnetic quadrupoles while the third-order geometrical aberrations are eliminated by octopoles. By placing these elements at distinct positions within the corrector, it is possible to successively eliminate the third-order aberrations in such a way that each subsequent correction does not affect the aberrations corrected in the preceding correction steps

Measurement of eye aberrations in a speckle field

International Nuclear Information System (INIS)

Larichev, A V; Ivanov, P V; Iroshnikov, N G; Shmalgauzen, V I

2001-01-01

The influence of speckles on the performance of a Shark-Hartmann wavefront sensor is investigated in the eye aberration studies. The dependence of the phase distortion measurement error on the characteristic speckle size is determined experimentally. Scanning of the reference source was used to suppress the speckle structure of the laser beam scattered by the retina. The technique developed by us made it possible to study the time dependence of the human eye aberrations with a resolution of 30 ms. (laser applications and other topics in quantum electronics)

Phase Aberration and Attenuation Effects on Acoustic Radiation Force-Based Shear Wave Generation.

Science.gov (United States)

Carrascal, Carolina Amador; Aristizabal, Sara; Greenleaf, James F; Urban, Matthew W

2016-02-01

Elasticity is measured by shear wave elasticity imaging (SWEI) methods using acoustic radiation force to create the shear waves. Phase aberration and tissue attenuation can hamper the generation of shear waves for in vivo applications. In this study, the effects of phase aberration and attenuation in ultrasound focusing for creating shear waves were explored. This includes the effects of phase shifts and amplitude attenuation on shear wave characteristics such as shear wave amplitude, shear wave speed, shear wave center frequency, and bandwidth. Two samples of swine belly tissue were used to create phase aberration and attenuation experimentally. To explore the phase aberration and attenuation effects individually, tissue experiments were complemented with ultrasound beam simulations using fast object-oriented C++ ultrasound simulator (FOCUS) and shear wave simulations using finite-element-model (FEM) analysis. The ultrasound frequency used to generate shear waves was varied from 3.0 to 4.5 MHz. Results: The measured acoustic pressure and resulting shear wave amplitude decreased approximately 40%-90% with the introduction of the tissue samples. Acoustic intensity and shear wave displacement were correlated for both tissue samples, and the resulting Pearson's correlation coefficients were 0.99 and 0.97. Analysis of shear wave generation with tissue samples (phase aberration and attenuation case), measured phase screen, (only phase aberration case), and FOCUS/FEM model (only attenuation case) showed that tissue attenuation affected the shear wave generation more than tissue aberration. Decreasing the ultrasound frequency helped maintain a focused beam for creation of shear waves in the presence of both phase aberration and attenuation.

[Frequency of chromosome aberrations in residents of the Semipalatinsk Oblast].

Science.gov (United States)

Gubitskaia, E G; Akhmatullina, N B; Vsevolodov, E B; Bishnevskaia, S S; Sharipov, I K; Cherednichenko, O G

1999-06-01

Cytogenetic analysis of the population of the Beskaragai district of the Semipalatinsk oblast adjacent to the territory of the nuclear test site was conducted by means of an ecological genetic questionnaire and cytogenetic examination of metaphase chromosomes. An increase in the total mutation level in the region was observed. The frequency of chromosome aberrations among the population of the Beskaragai district (3.2%) was statistically significantly (about 1.5 times) higher than the background levels in the clear regions (from 1 to 2%). Furthermore, the frequency of aberrations in adolescents was comparable with that in the adults. The spectrum of chromosome aberrations pointed to a significant contribution of radiation component to the mutagenesis.

Canine urothelial carcinoma: genomically aberrant and comparatively relevant.

Science.gov (United States)

Shapiro, S G; Raghunath, S; Williams, C; Motsinger-Reif, A A; Cullen, J M; Liu, T; Albertson, D; Ruvolo, M; Bergstrom Lucas, A; Jin, J; Knapp, D W; Schiffman, J D; Breen, M

2015-06-01

Urothelial carcinoma (UC), also referred to as transitional cell carcinoma (TCC), is the most common bladder malignancy in both human and canine populations. In human UC, numerous studies have demonstrated the prevalence of chromosomal imbalances. Although the histopathology of the disease is similar in both species, studies evaluating the genomic profile of canine UC are lacking, limiting the discovery of key comparative molecular markers associated with driving UC pathogenesis. In the present study, we evaluated 31 primary canine UC biopsies by oligonucleotide array comparative genomic hybridization (oaCGH). Results highlighted the presence of three highly recurrent numerical aberrations: gain of dog chromosome (CFA) 13 and 36 and loss of CFA 19. Regional gains of CFA 13 and 36 were present in 97 % and 84 % of cases, respectively, and losses on CFA 19 were present in 77 % of cases. Fluorescence in situ hybridization (FISH), using targeted bacterial artificial chromosome (BAC) clones and custom Agilent SureFISH probes, was performed to detect and quantify these regions in paraffin-embedded biopsy sections and urine-derived urothelial cells. The data indicate that these three aberrations are potentially diagnostic of UC. Comparison of our canine oaCGH data with that of 285 human cases identified a series of shared copy number aberrations. Using an informatics approach to interrogate the frequency of copy number aberrations across both species, we identified those that had the highest joint probability of association with UC. The most significant joint region contained the gene PABPC1, which should be considered further for its role in UC progression. In addition, cross-species filtering of genome-wide copy number data highlighted several genes as high-profile candidates for further analysis, including CDKN2A, S100A8/9, and LRP1B. We propose that these common aberrations are indicative of an evolutionarily conserved mechanism of pathogenesis and harbor genes

Widespread alternative and aberrant splicing revealed by lariat sequencing

Science.gov (United States)

Stepankiw, Nicholas; Raghavan, Madhura; Fogarty, Elizabeth A.; Grimson, Andrew; Pleiss, Jeffrey A.

2015-01-01

Alternative splicing is an important and ancient feature of eukaryotic gene structure, the existence of which has likely facilitated eukaryotic proteome expansions. Here, we have used intron lariat sequencing to generate a comprehensive profile of splicing events in Schizosaccharomyces pombe, amongst the simplest organisms that possess mammalian-like splice site degeneracy. We reveal an unprecedented level of alternative splicing, including alternative splice site selection for over half of all annotated introns, hundreds of novel exon-skipping events, and thousands of novel introns. Moreover, the frequency of these events is far higher than previous estimates, with alternative splice sites on average activated at ∼3% the rate of canonical sites. Although a subset of alternative sites are conserved in related species, implying functional potential, the majority are not detectably conserved. Interestingly, the rate of aberrant splicing is inversely related to expression level, with lowly expressed genes more prone to erroneous splicing. Although we validate many events with RNAseq, the proportion of alternative splicing discovered with lariat sequencing is far greater, a difference we attribute to preferential decay of aberrantly spliced transcripts. Together, these data suggest the spliceosome possesses far lower fidelity than previously appreciated, highlighting the potential contributions of alternative splicing in generating novel gene structures. PMID:26261211

Spatio-temporal Eigenvector Filtering: Application on Bioenergy Crop Impacts

Science.gov (United States)

Wang, M.; Kamarianakis, Y.; Georgescu, M.

2017-12-01

A suite of 10-year ensemble-based simulations was conducted to investigate the hydroclimatic impacts due to large-scale deployment of perennial bioenergy crops across the continental United States. Given the large size of the simulated dataset (about 60Tb), traditional hierarchical spatio-temporal statistical modelling cannot be implemented for the evaluation of physics parameterizations and biofuel impacts. In this work, we propose a filtering algorithm that takes into account the spatio-temporal autocorrelation structure of the data while avoiding spatial confounding. This method is used to quantify the robustness of simulated hydroclimatic impacts associated with bioenergy crops to alternative physics parameterizations and observational datasets. Results are evaluated against those obtained from three alternative Bayesian spatio-temporal specifications.

Cancer biomarkers defined by autoantibody signatures to aberrant O-glycopeptide epitopes

DEFF Research Database (Denmark)

Wandall, Hans H; Blixt, Ola; Tarp, Mads A

2010-01-01

Autoantibodies to cancer antigens hold promise as biomarkers for early detection of cancer. Proteins that are aberrantly processed in cancer cells are likely to present autoantibody targets. The extracellular mucin MUC1 is overexpressed and aberrantly glycosylated in many cancers; thus, we evalua...

Impact of types of lymphocyte chromosomal aberrations on human cancer risk

DEFF Research Database (Denmark)

Hagmar, Lars; Strömberg, Ulf; Bonassi, Stefano

2004-01-01

The frequency of cells with structural chromosomal aberrations (CAs) in peripheral blood lymphocytes is the first genotoxicity biomarker that has shown an association with cancer risk. CAs are usually divided into chromosome-type (CSAs) and chromatid-type aberrations (CTAs), with different mechan...

Spatiotemporal radiotherapy planning using a global optimization approach

Science.gov (United States)

Adibi, Ali; Salari, Ehsan

2018-02-01

This paper aims at quantifying the extent of potential therapeutic gain, measured using biologically effective dose (BED), that can be achieved by altering the radiation dose distribution over treatment sessions in fractionated radiotherapy. To that end, a spatiotemporally integrated planning approach is developed, where the spatial and temporal dose modulations are optimized simultaneously. The concept of equivalent uniform BED (EUBED) is used to quantify and compare the clinical quality of spatiotemporally heterogeneous dose distributions in target and critical structures. This gives rise to a large-scale non-convex treatment-plan optimization problem, which is solved using global optimization techniques. The proposed spatiotemporal planning approach is tested on two stylized cancer cases resembling two different tumor sites and sensitivity analysis is performed for radio-biological and EUBED parameters. Numerical results validate that spatiotemporal plans are capable of delivering a larger BED to the target volume without increasing the BED in critical structures compared to conventional time-invariant plans. In particular, this additional gain is attributed to the irradiation of different regions of the target volume at different treatment sessions. Additionally, the trade-off between the potential therapeutic gain and the number of distinct dose distributions is quantified, which suggests a diminishing marginal gain as the number of dose distributions increases.

Spatio-temporal databases complex motion pattern queries

CERN Document Server

Vieira, Marcos R

2013-01-01

This brief presents several new query processing techniques, called complex motion pattern queries, specifically designed for very large spatio-temporal databases of moving objects. The brief begins with the definition of flexible pattern queries, which are powerful because of the integration of variables and motion patterns. This is followed by a summary of the expressive power of patterns and flexibility of pattern queries. The brief then present the Spatio-Temporal Pattern System (STPS) and density-based pattern queries. STPS databases contain millions of records with information about mobi

Three-dimensional optical transfer functions in the aberration-corrected scanning transmission electron microscope.

Science.gov (United States)

Jones, L; Nellist, P D

2014-05-01

In the scanning transmission electron microscope, hardware aberration correctors can now correct for the positive spherical aberration of round electron lenses. These correctors make use of nonround optics such as hexapoles or octupoles, leading to the limiting aberrations often being of a nonround type. Here we explore the effect of a number of potential limiting aberrations on the imaging performance of the scanning transmission electron microscope through their resulting optical transfer functions. In particular, the response of the optical transfer function to changes in defocus are examined, given that this is the final aberration to be tuned just before image acquisition. The resulting three-dimensional optical transfer functions also allow an assessment of the performance of a system for focal-series experiments or optical sectioning applications. © 2014 The Authors Journal of Microscopy © 2014 Royal Microscopical Society.

Stable and unstable chromosomal aberrations in workers at nuclear waste repository

International Nuclear Information System (INIS)

Hadjidekova, V.; Atanasova, P.; Iovchev, M.; Agova, S.

2004-01-01

A cytogenetic analysis of chromosomal aberrations was performed on 15 workers from final nuclear waste repository 'Novi Han'. The frequency of chromosomal aberrations were estimated in peripheral blood lymphocytes by conventional staining with Giemza and fluorescent in situ hybridization staining (FISH) using DNA specific probes. The results are compared with a control group from the administrative staff of the radioactive storage. All persons were interviewed by a special questionnaire list for professional, medical, and social status. The comparison of the results does not show increase of the frequency of unstable chromosomal aberrations detected by conventional staining. The frequency of stable chromosomal aberrations detected by FISH were significantly higher in workers group than in controls, although the statistical significance is low. The results show that FISH test is found to be more sensitive than conventional chromosomal analysis as a cytogenetic monitor test of the occupationally exposed subjects. (authors)

Aberrant dopamine D2-like receptor function in a rodent model of schizophrenia.

Science.gov (United States)

Perez, Stephanie M; Lodge, Daniel J

2012-11-01

Based on the observation that antipsychotic medications display antagonist properties at dopamine D2-like receptors, aberrant dopamine signaling has been proposed to underlie psychosis in patients with schizophrenia. Thus, it is not surprising that considerable research has been devoted to understanding the mechanisms involved in the antipsychotic action of these compounds. It is important to note that the majority of these studies have been performed in "normal" experimental animals. Given that these animals do not possess the aberrant neuronal information processing typically associated with schizophrenia, the aim of the current study was to examine the dopamine D2 receptor system in a rodent model of schizophrenia. Here, we demonstrate that methylazoxymethanol acetate (MAM)-treated rats display an enhanced effect of quinpirole on dopamine neuron activity and an aberrant locomotor response to D2-like receptor activation, suggesting changes in postsynaptic D2-like receptor function. To better understand the mechanisms underlying the enhanced response to D2-like ligands in MAM-treated rats, we examined the expression of D2, D3, and dopamine transporter mRNA in the nucleus accumbens and ventral tegmental area by quantitative reverse transcription-polymerase chain reaction. MAM-treated rats displayed a significant increase in dopamine D3 receptor mRNA expression in the nucleus accumbens with no significant changes in the expression of the D2 receptor. Taken together, these data demonstrate robust alterations in dopamine D2-like receptor function in a rodent model of schizophrenia and provide evidence that preclinical studies examining the mechanisms of antipsychotic drug action should be performed in animal models that mirror aspects of the abnormal neuronal transmission thought to underlie symptoms of schizophrenia.

Children with asthma by school age display aberrant immune responses to pathogenic airway bacteria as infants

DEFF Research Database (Denmark)

Larsen, Jeppe Madura; Pedersen, Susanne Brix; Thysen, Anna Hammerich

2014-01-01

childhood asthma. We hypothesized that children with asthma have an abnormal immune response to pathogenic bacteria in infancy. ObjectiveWe aimed to assess the bacterial immune response in asymptomatic infants and the association with later development of asthma by age 7 years. MethodsThe Copenhagen...... was assessed based on the pattern of cytokines produced and T-cell activation. ResultsThe immune response to pathogenic bacteria was different in infants with asthma by 7 years of age (P = .0007). In particular, prospective asthmatic subjects had aberrant production of IL-5 (P = .008), IL-13 (P = .057), IL-17...... (P = .001), and IL-10 (P = .028), whereas there were no differences in T-cell activation or peripheral T-cell composition. ConclusionsChildren with asthma by school age exhibited an aberrant immune response to pathogenic bacteria in infancy. We propose that an abnormal immune response to pathogenic...

Descriptive evaluation of chromosome aberrations in blood lymphocytes due to gamma-irradiation

International Nuclear Information System (INIS)

Medina III, F.S.; Gregorio, J.S.; Vinoya, P.C.; Panlaque, C.A.

1983-01-01

To induce and evaluate the effect of radiation among Filipinos, frequencies and types of ν-ray induced chromosome aberrations were studied with peripheral lymphocytes from 19 donors. Peripheral blood samples were irradiated at 0 Gray, 500 mGy, 1 Gy, 2 Gy, 3 Gy and 4 Gy. Irradiated blood samples were cultured by the same standard technique as that commonly used for human blood lymphocytes. Our observations showed that irradiation causes chromosomal aberration similar to effects observed in Caucasians. Our study confirm that irradiation causes an increase of the chromosome aberrations types normally found in the control (gaps, chromatid breaks and chromosome fragments) and can induce aberrations which are rarely observed in non-exposed individual (deletions, translocations, polycentrics, rings, and despiralizations). (author)

[The polymorphism of catechol-O-methyltransferase (COMT) and hemochromatosis (HFE) genes in the radiocontaminated regions residents with different chromosome aberration frequency].

Science.gov (United States)

Ivanova, T I; Kondrashova, T V; Krikunova, L I; Smirnova, I A; Shentereva, N I; Sychenkova, N I; Rykova, E V; Zharikova, I A; Khorokhorina, V A; Riabchenko, N I; Zamulaeva, I A

2010-01-01

The association between polymorphisms in genes COMT, HFE that takes part in oxidative stress regulation, and chromosome aberration frequency in lymphocytes was assessed in 278 female residents of radiation polluted regions of Central Russia: Bryansk (322 kBk/m2) and Tula Districts (137Cs - 171 kBk/m2). The C187G, G845A genotyping of HFE and G1947A (H/L) of COMT was done by means of polymerase chain reaction-restriction fragment length polymorphism. Studied population was divided into 3 subgroups by level of chromosome aberrations per cell (0-2, 3-4, >5). There was shown statistically significant difference in distribution of COMTand HFE genotypes between the groups. The high frequency of chromosome aberrations (> or = 5%) was associated with homozygotes of the high activity COMT G/G and HFE CC. Heterozygotes for G1947A COMT and C187G HFE reveal negative association with the high frequency of chromosome aberrations and correspond to "resistance factors".

Chromosome aberration frequency in blood lymphocytes of animals with 239Pu lung burdens

International Nuclear Information System (INIS)

Brooks, A.L.; LaBauve, R.J.; McClellan, R.O.; Jensen, D.A.

1976-01-01

Other investigators have suggested a causal relationship between accidental 239 Pu exposures in man and the presence of chromosome aberrations in blood lymphocytes. For experimental assessment of this relationship, 16 rhesus monkeys and 171 Chinese hamsters were exposed to 239 PuO 2 aerosols and an additional five hamsters were injected with 239 Pu citrate, and the frequency of aberrations in blood lymphocyte was determined. Hamsters with the highest lung burden had a median survival time of about 80 days. No deaths occurred in any of the other treated hamsters or monkeys by 250 days after 239 Pu inhalation. Hamsters sacrificed at 30 days showed an increase in chromosome aberration frequency with increasing dose to lungs. By 120 days after inhalation, the aberration frequency in the controls was 0.012. The frequency in animals with doses that produced significant life shortening had decreased to 0.018 and to 0.032 aberration/cell in animals with lower doses. At 380 days after injection of 2 nCi of 239 Pu citrate per gram of body weight, hamster lymphocytes had an aberration frequency of 0.048 aberration/cell. The level of chromosome damage in the 239 PuO 2 -exposed monkeys at 30 and 90 days after inhalation was not different from that observed in controls. Possible reasons for differences between the experimental animal observations and findings in man are discussed

Transition to turbulence via spatiotemporal intermittency in stimulated Raman backscattering

International Nuclear Information System (INIS)

Skoric, M.M.; Jovanovic, M.S.; Rajkovic, M.R.

1996-01-01

The spatiotemporal evolution of stimulated Raman backscattering in a bounded, uniform, weakly dissipative plasma is studied. The nonlinear model of a three-wave interaction involves a quadratic coupling of slowly varying complex amplitudes of the laser pump, the backscattered and the electron plasma wave. The corresponding set of coupled partial differential equations with nonlinear phase detuning that is taken into account is solved numerically in space time with fixed nonzero source boundary conditions. The study of the above open, convective, weakly confined system reveals a quasiperiodic transition to spatiotemporal chaos via spatiotemporal intermittency. In the analysis of transitions a dual scheme borrowed from fields of nonlinear dynamics and statistical physics is applied. An introduction of a nonlinear three-wave interaction to a growing family of paradigmatic equations which exhibit a route to turbulence via spatiotemporal intermittency is outlined in this work. copyright 1996 The American Physical Society

Explanation of test and assessment of chromosomal aberrations on occupational health examinations for radiation workers

International Nuclear Information System (INIS)

Lu Yumin; Fu Baohua; Han Lin; Wang Xi'ai; Zhao Fengling

2012-01-01

Test and Assessment of Chromosomal Aberrations on Occupational Health Examinations for Radiation Workers was formulated for standardizing analysis and outcome assessment of chromosomal aberrations on occupational health examinations for radiation workers. In order to provide experimental and theoretical basis for implementation and extension of this standard, this paper interpreted the standard comprehensively, including some existed problems that methods on detection and outcome assessment of chromosomal aberrations is not unified in different laboratories in China, and related criteria,laws and regulations at home and abroad are not fit for the detection of chromosomal aberrations for radiation workers very well; some introduction on methods of chromosomal slide preparation, discriminant analysis and outcome assessment of chromosomal aberration; and some influencing factors in the quality of chromosomal aberration detection. (authors)

Aberrant neural networks for the recognition memory of socially relevant information in patients with schizophrenia.

Science.gov (United States)

Oh, Jooyoung; Chun, Ji-Won; Kim, Eunseong; Park, Hae-Jeong; Lee, Boreom; Kim, Jae-Jin

2017-01-01

Patients with schizophrenia exhibit several cognitive deficits, including memory impairment. Problems with recognition memory can hinder socially adaptive behavior. Previous investigations have suggested that altered activation of the frontotemporal area plays an important role in recognition memory impairment. However, the cerebral networks related to these deficits are not known. The aim of this study was to elucidate the brain networks required for recognizing socially relevant information in patients with schizophrenia performing an old-new recognition task. Sixteen patients with schizophrenia and 16 controls participated in this study. First, the subjects performed the theme-identification task during functional magnetic resonance imaging. In this task, pictures depicting social situations were presented with three words, and the subjects were asked to select the best theme word for each picture. The subjects then performed an old-new recognition task in which they were asked to discriminate whether the presented words were old or new. Task performance and neural responses in the old-new recognition task were compared between the subject groups. An independent component analysis of the functional connectivity was performed. The patients with schizophrenia exhibited decreased discriminability and increased activation of the right superior temporal gyrus compared with the controls during correct responses. Furthermore, aberrant network activities were found in the frontopolar and language comprehension networks in the patients. The functional connectivity analysis showed aberrant connectivity in the frontopolar and language comprehension networks in the patients with schizophrenia, and these aberrations possibly contribute to their low recognition performance and social dysfunction. These results suggest that the frontopolar and language comprehension networks are potential therapeutic targets in patients with schizophrenia.

Automatic phase aberration compensation for digital holographic microscopy based on deep learning background detection.

Science.gov (United States)

Nguyen, Thanh; Bui, Vy; Lam, Van; Raub, Christopher B; Chang, Lin-Ching; Nehmetallah, George

2017-06-26

We propose a fully automatic technique to obtain aberration free quantitative phase imaging in digital holographic microscopy (DHM) based on deep learning. The traditional DHM solves the phase aberration compensation problem by manually detecting the background for quantitative measurement. This would be a drawback in real time implementation and for dynamic processes such as cell migration phenomena. A recent automatic aberration compensation approach using principle component analysis (PCA) in DHM avoids human intervention regardless of the cells' motion. However, it corrects spherical/elliptical aberration only and disregards the higher order aberrations. Traditional image segmentation techniques can be employed to spatially detect cell locations. Ideally, automatic image segmentation techniques make real time measurement possible. However, existing automatic unsupervised segmentation techniques have poor performance when applied to DHM phase images because of aberrations and speckle noise. In this paper, we propose a novel method that combines a supervised deep learning technique with convolutional neural network (CNN) and Zernike polynomial fitting (ZPF). The deep learning CNN is implemented to perform automatic background region detection that allows for ZPF to compute the self-conjugated phase to compensate for most aberrations.

Chromosome aberrations induced by 135 MeV of carbon and neon beams by PRC

International Nuclear Information System (INIS)

Ohara, Hiroshi; Minamihisamatu, Masako; Kanai, Tatsuaki; Eguchi-Kasai, Kiyomi; Itsukaichi, Hiromi; Fukutsu, Kumiko; Yatagai, Fumio; Sato, Kohki.

1993-01-01

Radiation-induced chromosome aberration can be an indicator of the radiation lesions in irradiated cells. Many studies on chromosome aberration induced by X-ray and γ - ray have indicated that the dose response of the aberration can be fitted to a quadratic equation, Y = αD + βD 2 , and it becomes linear as the LET of beams increases. The main subject of this study was some quantification of chromosomal aberration induced by 135 MeV/n carbon and neon beams produced by the RRC, the operation of which increasingly became useful for the studies on heavy ion biology. The results will meet with some of the radiobiological features connected to the specific action of charged particles. The materials used, the experimental method and the results are reported. Four curves of the dose response for the production of dicentric and ring types of aberration induced by carbon and neon beams and four different dose average LETs are given. Aberration production rate became higher as LET increased. Chromosome aberration can be quantified as an indicator of radiation lesions in the case of high LET particle radiation. (K.I.)

Influence of atmospheric turbulence on the energy focusability of Gaussian beams with spherical aberration

International Nuclear Information System (INIS)

Deng, Jinping; Ji, Xiaoling

2014-01-01

By using the four-dimensional (4D) computer code of the time-dependent propagation of laser beams through atmospheric turbulence, the influence of atmospheric turbulence on the energy focusability of Gaussian beams with spherical aberration is studied in detail, where the mean-squared beam width, the power in the bucket (PIB), the β parameter and the energy Strehl ratio are taken as the characteristic parameters. It is shown that turbulence results in beam spreading, and the effect of spherical aberration on the beam spreading decreases due to turbulence. Gaussian beams with negative spherical aberration are more affected by turbulence than those with positive spherical aberration. For the negative spherical aberration case, the focus position moves to the source plane due to turbulence. It is mentioned that the influence of turbulence on the energy focusability defined by a certain energy (i.e. PIB = 63%) is very heavy when the negative spherical aberration is very heavy. On the other hand, the influence of turbulence on the energy focusability defined by the energy within a given bucket radius (i.e. mean-squared beam width) is heaviest when a certain negative spherical aberration coefficient is adopted. (papers)

Aberrant behavior and cognitive ability in preschool children

Directory of Open Access Journals (Sweden)

Bala Gustav

2007-01-01

Full Text Available The sample included 712 preschool boys and girls at the age of 4 to 7 years (mean 5.96 decimal years and standard deviation .96 from preschool institutions in Novi Sad, Sombor, Sremska Mitrovica and Bačka Palanka. Information concerning 36 indicators of aberrant behavior of the children were supplied by their parents, whereas their cognitive ability was tested by Raven’s progressive colored matrices. Based on factor analysis (promax method, four factors i.e. generators of aberrant behavior in children were singled out: aggression, anxiousness, dissociation, and hysteria, whose relations with cognitive functioning and age were also analyzed by factor analysis. Aberrant behavior and cognitive abilities show significant interrelatedness. Owing to orderly developed cognitive abilities, a child understands essence and reality of problems, realizes possibilities and manners of solving them, and succeeds in realizing successful psycho-social functioning. Developed cognitive abilities enable a child to recognize and understand her/his own reactions in different situations and develop manners of reacting, which leads to strengthening psycho-social safety and adapting behavior in accordance with her/his age and abilities.

Comparison of Spatiotemporal Mapping Techniques for Enormous Etl and Exploitation Patterns

Science.gov (United States)

Deiotte, R.; La Valley, R.

2017-10-01

The need to extract, transform, and exploit enormous volumes of spatiotemporal data has exploded with the rise of social media, advanced military sensors, wearables, automotive tracking, etc. However, current methods of spatiotemporal encoding and exploitation simultaneously limit the use of that information and increase computing complexity. Current spatiotemporal encoding methods from Niemeyer and Usher rely on a Z-order space filling curve, a relative of Peano's 1890 space filling curve, for spatial hashing and interleaving temporal hashes to generate a spatiotemporal encoding. However, there exist other space-filling curves, and that provide different manifold coverings that could promote better hashing techniques for spatial data and have the potential to map spatiotemporal data without interleaving. The concatenation of Niemeyer's and Usher's techniques provide a highly efficient space-time index. However, other methods have advantages and disadvantages regarding computational cost, efficiency, and utility. This paper explores the several methods using a range of sizes of data sets from 1K to 10M observations and provides a comparison of the methods.

COMPARISON OF SPATIOTEMPORAL MAPPING TECHNIQUES FOR ENORMOUS ETL AND EXPLOITATION PATTERNS

Directory of Open Access Journals (Sweden)

R. Deiotte

2017-10-01

Full Text Available The need to extract, transform, and exploit enormous volumes of spatiotemporal data has exploded with the rise of social media, advanced military sensors, wearables, automotive tracking, etc. However, current methods of spatiotemporal encoding and exploitation simultaneously limit the use of that information and increase computing complexity. Current spatiotemporal encoding methods from Niemeyer and Usher rely on a Z-order space filling curve, a relative of Peano’s 1890 space filling curve, for spatial hashing and interleaving temporal hashes to generate a spatiotemporal encoding. However, there exist other space-filling curves, and that provide different manifold coverings that could promote better hashing techniques for spatial data and have the potential to map spatiotemporal data without interleaving. The concatenation of Niemeyer’s and Usher’s techniques provide a highly efficient space-time index. However, other methods have advantages and disadvantages regarding computational cost, efficiency, and utility. This paper explores the several methods using a range of sizes of data sets from 1K to 10M observations and provides a comparison of the methods.

Chromosome aberration assays in barley (Hordeum vulgare)

Energy Technology Data Exchange (ETDEWEB)

Constantin, M J [Univ. of Tennessee, Knoxville; Nilan, R A

1982-01-01

Barley is an exceellent organism for studies of induced chromosome aberrations because of its few (2n = 2x = 14) relatively large chromosomes. Root-tip and shoot-tip cells have been used extensively for the study of ionizing radiation-induced chromosome aberrations. The general procedures are well known, the technology is simple and easy to learn, and the assays are relatively quick and inexpensive. Both root tips and shoot tips can be used for the study of chemical mutagens as well as ionizing radiations. Pollen mother cells are well suited for studying the effects of mutagens on meiotic chromosomes. The literature review for the Gene-Tox Program reported on 61 chemicals tested for their effects on barley chromosomes. Of these, 90% were reported to be either positive or positive dose-related, while 7% were negative and 3% were questionable. Barley assays based on chromosomal aberrations are useful to detect the clastogenic potency of chemicals under laboratory conditions. Indications are that the data from barley can be used to corroborate data obtained from other organisms. Among the classes of chemicals assayed were: alcohols and phenols; alkaloids; epoxides; alkyl sulfates; amides and sulfonamides; aromatic amines; aryl halides; aziridines; alkenes; carbamates; hydroazides; nitroaromatics; nitrosamides; nitrosources; phenothiazines; and polycyclic aromatic hydrocarbons.

Study of chromosome aberrations on the workers occupationally exposed to thorium and rare earth mixed dust

International Nuclear Information System (INIS)

Zhang Wei; Wang Chunyan; Lv Huiming; Zhang Cuilan; Hao Shuxia; Su Xu; Jia Kejun; Liu Yufei

2008-01-01

Objective: To study the effect of thorium and rare earth mixed dust on chromosome aberrations in the lymphocytes of occupational exposed workers. Methods: Analyses of unstable chromosome aberrations on 53 occupational exposed workers and 58 control workers were carried out by the conventional Giemsa staining method. Fluorescence in situ hybridization method was performed to analyze the chromosome stable aberrations on 10 occupational exposed workers and l0 control workers. Results: The frequencies of chromosomal aberration cells, dicentrics plus rings, total aberrations in exposed workers were significantly higher than those in controls. No significant difference was found in the frequency of acentric aberrations between exposed and non-exposed workers. No significant difference was found in the frequency of translocations between exposed and non-exposed workers. Conclusions: Chronically occupational exposure to thorium and rare earth mixed dust can increase the induction of unstable chromosome aberration, but the increase of stable chromosome aberrations (translocation) can not be observed. (authors)

Research on spatio-temporal database techniques for spatial information service

Science.gov (United States)

Zhao, Rong; Wang, Liang; Li, Yuxiang; Fan, Rongshuang; Liu, Ping; Li, Qingyuan

2007-06-01

Geographic data should be described by spatial, temporal and attribute components, but the spatio-temporal queries are difficult to be answered within current GIS. This paper describes research into the development and application of spatio-temporal data management system based upon GeoWindows GIS software platform which was developed by Chinese Academy of Surveying and Mapping (CASM). Faced the current and practical requirements of spatial information application, and based on existing GIS platform, one kind of spatio-temporal data model which integrates vector and grid data together was established firstly. Secondly, we solved out the key technique of building temporal data topology, successfully developed a suit of spatio-temporal database management system adopting object-oriented methods. The system provides the temporal data collection, data storage, data management and data display and query functions. Finally, as a case study, we explored the application of spatio-temporal data management system with the administrative region data of multi-history periods of China as the basic data. With all the efforts above, the GIS capacity of management and manipulation in aspect of time and attribute of GIS has been enhanced, and technical reference has been provided for the further development of temporal geographic information system (TGIS).

An evaluation of space time cube representation of spatiotemporal patterns.

Science.gov (United States)

Kristensson, Per Ola; Dahlbäck, Nils; Anundi, Daniel; Björnstad, Marius; Gillberg, Hanna; Haraldsson, Jonas; Mårtensson, Ingrid; Nordvall, Mathias; Ståhl, Josefine

2009-01-01

Space time cube representation is an information visualization technique where spatiotemporal data points are mapped into a cube. Information visualization researchers have previously argued that space time cube representation is beneficial in revealing complex spatiotemporal patterns in a data set to users. The argument is based on the fact that both time and spatial information are displayed simultaneously to users, an effect difficult to achieve in other representations. However, to our knowledge the actual usefulness of space time cube representation in conveying complex spatiotemporal patterns to users has not been empirically validated. To fill this gap, we report on a between-subjects experiment comparing novice users' error rates and response times when answering a set of questions using either space time cube or a baseline 2D representation. For some simple questions, the error rates were lower when using the baseline representation. For complex questions where the participants needed an overall understanding of the spatiotemporal structure of the data set, the space time cube representation resulted in on average twice as fast response times with no difference in error rates compared to the baseline. These results provide an empirical foundation for the hypothesis that space time cube representation benefits users analyzing complex spatiotemporal patterns.

Delayed formation of chromosome aberrations in mouse pachytebne spermatocytes treated with triethylenemelamine (TEM)

International Nuclear Information System (INIS)

Generoso, W.M.; Krishna, M.; Sotomayor, R.E.; Cacheiro, N.L.A.

1977-01-01

Induction of chromosome aberrations in pachytene spermatocytes of mice by 2 mg/kg TEM was compared with induction by 400 R x rays. These doses induced comparably high dominant lethal effects in pachytene spermatocytes of mice. Cytological analysis at diakinesis-metaphase I stage showed that whereas 76.4% of the cells treated with x rays at pachytene stage had aberrations, the frequencies observed in two TEM experiments were only 0.8 and 2.2%. On the other hand, 5% of the progeny from TEM-treated pachytene spermatocytes were found to be translocation heterozygotes. This is the first report on the recovery of heritable translocations from treated spermatocytes of mice. The aberration frequencies observed for TEM in diakinesis-metaphase I were much too low to account for all the lethal mutations and heritable translocations. Thus, the formation of the bulk of aberrations induced by TEM in pachytene spermatocytes was delayed--a marked contrast to the more immediate formation of x-ray-induced aberrations. It is postulated that the formation of the bulk of TEM-induced aberrations in pachytene spermatocytes and in certain postmeiotic stages occurs sometime during spermiogenesis, and not through the operation of postfertilization pronuclear DNA synthesis

Persistence of radiation-induced chromosome aberrations in a long-term cell culture.

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Duran, Assumpta; Barquinero, Joan Francesc; Caballín, María Rosa; Ribas, Montserrat; Barrios, Leonardo

2009-04-01

The aim of the present study was to evaluate the persistence of chromosome aberrations induced by X rays. FISH painting and mFISH techniques were applied to long-term cultures of irradiated cells. With painting, at 2 Gy the frequency of apparently simple translocations remained almost invariable during all the culture, whereas at 4 Gy a rapid decline was observed between the first and the second samples, followed by a slight decrease until the end of the culture. Apparently simple dicentrics and complex aberrations disappeared after the first sample at 2 and 4 Gy. By mFISH, at 2 Gy the frequency of complete plus one-way translocations remained invariable between the first and last sample, but at 4 Gy a 60% decline was observed. True incomplete simple translocations disappeared at 2 and 4 Gy, indicating that incompleteness could be a factor to consider when the persistence of translocations is analyzed. The analysis by mFISH showed that the frequency of complex aberrations and their complexity increased with dose and tended to disappear in the last sample. Our results indicate that the influence of dose on the decrease in the frequency of simple translocations with time postirradiation cannot be fully explained by the disappearance of true incomplete translocations and complex aberrations. The chromosome involvement was random for radiation-induced exchange aberrations and non-random for total aberrations. Chromosome 7 showed the highest deviations from expected, being less and more involved than expected in the first and last samples, respectively. Some preferential chromosome-chromosome associations were observed, including a coincidence with a cluster from radiogenic chromosome aberrations described in other studies.

Accuracy of modal wavefront estimation from eye transverse aberration measurements

Science.gov (United States)

Chyzh, Igor H.; Sokurenko, Vyacheslav M.

2001-01-01

The influence of random errors in measurement of eye transverse aberrations on the accuracy of reconstructing wave aberration as well as ametropia and astigmatism parameters is investigated. The dependence of mentioned errors on a ratio between the number of measurement points and the number of polynomial coefficients is found for different pupil location of measurement points. Recommendations are proposed for setting these ratios.

Rainfall spatiotemporal variability relation to wetlands hydroperiods

Science.gov (United States)

Serrano-Hidalgo, Carmen; Guardiola-Albert, Carolina; Fernandez-Naranjo, Nuria

2017-04-01

Doñana natural space (Southwestern Spain) is one of the largest protected wetlands in Europe. The wide marshes present in this natural space have such ecological value that this wetland has been declared a Ramsar reserve in 1982. Apart from the extensive marsh, there are also small lagoons and seasonally flooded areas which are likewise essential to maintain a wide variety of valuable habitats. Hydroperiod, the length of time each point remains flooded along an annual cycle, is a critical ecological parameter that shapes aquatic plants and animals distribution and determines available habitat for many of the living organisms in the marshes. Recently, there have been published two different works estimating the hydroperiod of Doñana lagoons with Landsat Time Series images (Cifuentes et al., 2015; Díaz-Delgado et al., 2016). In both works the flooding cycle hydroperiod in Doñana marshes reveals a flooding regime mainly driven by rainfall, evapotranspiration, topography and local hydrological management actions. The correlation found between rainfall and hydroperiod is studied differently in both works. While in one the rainfall is taken from one raingauge (Cifuentes et al., 2015), the one performed by Díaz-Delgado (2016) uses annual rainfall maps interpolated with the inverse of the distance method. The rainfall spatiotemporal variability in this area can be highly significant; however the amount of this importance has not been quantified at the moment. In the present work the geostatistical tool known as spatiotemporal variogram is used to study the rainfall spatiotemporal variability. The spacetime package implemented in R (Pebesma, 2012) facilities its computation from a high rainfall data base of more than 100 raingauges from 1950 to 2016. With the aid of these variograms the rainfall spatiotemporal variability is quantified. The principal aim of the present work is the study of the relation between the rainfall spatiotemporal variability and the

Structural analysis of γ radiation-induced chromosomal aberrations observed by atomic force microscopy

International Nuclear Information System (INIS)

Qu Shuang; Chen Ying; Ge Shili; Liu Xiulin; Zhou Pingkun; Zhang Sa; Zhang Detian

2003-01-01

Objective: To find a new method for the measurement of radiation-induced damage, the structures of normal chromosomes and 60 Co γ-ray-induced chromosomal aberration were analyzed by atomic force microscopy. Methods: Normal and irradiated chromosomes of human peripheral blood lymphocytes were prepared, then three-dimensional structure and height of chromosomes were analyzed by atomic force microscopy. Results: Three-dimensional structures of normal chromosomes and dicentric aberration in irradiated chromosomes were observed clearly. The data of chromosome height were helpful to recognizing the dicentric aberrations. Conclusion: Atomic force microscopy providing three-dimension image and linear measurement is a new and valuable tool for structural analysis of radiation-induced chromosomal aberrations

Studies on the chromosome aberrations and isozyme patterns in cancer patients treated with therapeutic radiation

International Nuclear Information System (INIS)

Kim, J.J.

1979-09-01

The chromosome aberration yield of peripheral blood lymphocytes obtained from cancer patients who had been locally irradiated with therapeutic radiation seems to be largely influenced by total dose, loss of cell with aberration, irradiation interval and dose per day. When treatment period from 7 to 21 days and total dose range from 1000 to 3000 rad, the aberration yield is considered to change according to total dose and accumulated effect by continued existence of damaged chromosomes. However, loss of cell with aberration might play important role in chromosome aberration yield of peripheral blood lymphocytes obtained from those who had received radiation above 3000 rad. In case that other conditions make little difference, dose per day and irradiation interval are looked upon as important factors in aberration yield of lymphocyte chromosomes

Chromosome aberrations in human lymphocytes exposed to tritiated water in vitro

International Nuclear Information System (INIS)

Bocian, E.; Ziemba-zak, B.; Rosiek, O.; Sablinski, J.

1978-01-01

The induction of chromosome aberrations in human peripheral blood lymphocytes by tritiated water or 180 kV X-rays in vitro was studied. Lymphocytes were exposed to various concentrations of HTO for 2 h or for 53 h. Chromosome and chromatid type aberrations were scored during the first mitotic division after stimulation with phytohaemagglutinin. For the analysis of the dose-response relationship the data were fitted by the method of least-squares to different models. After acute exposure to tritium β-rays and X-rays, the dicentrics + centric rings and terminal + interstitial deletions gave the best fit to the linear-quadratic function. However, data for these types of aberrations after 53 h exposure to HTO gave equally good fit to the linear and linear-quadratic functions. The best description of the dose-response relationship for chromatid aberrations is given by the linear model. In the system studied the RBE of tritium β-rays as compared to 180 KV X-rays was 1.17+-0.02. (Auth.)

Aberration measurement of projection optics in lithographic tools based on two-beam interference theory

International Nuclear Information System (INIS)

Ma Mingying; Wang Xiangzhao; Wang Fan

2006-01-01

The degradation of image quality caused by aberrations of projection optics in lithographic tools is a serious problem in optical lithography. We propose what we believe to be a novel technique for measuring aberrations of projection optics based on two-beam interference theory. By utilizing the partial coherent imaging theory, a novel model that accurately characterizes the relative image displacement of a fine grating pattern to a large pattern induced by aberrations is derived. Both even and odd aberrations are extracted independently from the relative image displacements of the printed patterns by two-beam interference imaging of the zeroth and positive first orders. The simulation results show that by using this technique we can measure the aberrations present in the lithographic tool with higher accuracy

Aberration measurement of projection optics in lithographic tools based on two-beam interference theory.

Science.gov (United States)

Ma, Mingying; Wang, Xiangzhao; Wang, Fan

2006-11-10

The degradation of image quality caused by aberrations of projection optics in lithographic tools is a serious problem in optical lithography. We propose what we believe to be a novel technique for measuring aberrations of projection optics based on two-beam interference theory. By utilizing the partial coherent imaging theory, a novel model that accurately characterizes the relative image displacement of a fine grating pattern to a large pattern induced by aberrations is derived. Both even and odd aberrations are extracted independently from the relative image displacements of the printed patterns by two-beam interference imaging of the zeroth and positive first orders. The simulation results show that by using this technique we can measure the aberrations present in the lithographic tool with higher accuracy.

Correcting the wavefront aberration of membrane mirror based on liquid crystal spatial light modulator

Science.gov (United States)

Yang, Bin; Wei, Yin; Chen, Xinhua; Tang, Minxue

2014-11-01

Membrane mirror with flexible polymer film substrate is a new-concept ultra lightweight mirror for space applications. Compared with traditional mirrors, membrane mirror has the advantages of lightweight, folding and deployable, low cost and etc. Due to the surface shape of flexible membrane mirror is easy to deviate from the design surface shape, it will bring wavefront aberration to the optical system. In order to solve this problem, a method of membrane mirror wavefront aberration correction based on the liquid crystal spatial light modulator (LCSLM) will be studied in this paper. The wavefront aberration correction principle of LCSLM is described and the phase modulation property of a LCSLM is measured and analyzed firstly. Then the membrane mirror wavefront aberration correction system is designed and established according to the optical properties of a membrane mirror. The LCSLM and a Hartmann-Shack sensor are used as a wavefront corrector and a wavefront detector, respectively. The detected wavefront aberration is calculated and converted into voltage value on LCSLM for the mirror wavefront aberration correction by programming in Matlab. When in experiment, the wavefront aberration of a glass plane mirror with a diameter of 70 mm is measured and corrected for verifying the feasibility of the experiment system and the correctness of the program. The PV value and RMS value of distorted wavefront are reduced and near diffraction limited optical performance is achieved. On this basis, the wavefront aberration of the aperture center Φ25 mm in a membrane mirror with a diameter of 200 mm is corrected and the errors are analyzed. It provides a means of correcting the wavefront aberration of membrane mirror.

Markovian Limit of a Spatio-Temporal Correlated Open Systems

Science.gov (United States)

Monnai, T.

Large fluctuation of Brownian particles is affected by the finiteness of the correlation length of the background noise field. Indeed a Fokker—Planck equation is derived in a Markovian limit of a spatio-temporal short correlated noise. Corresponding kinetic quantities are renormalized due to the spatio-temporal memory. We also investigate the case of open system by connecting a thermostat to the system.

Spatio-temporal models of mental processes from fMRI.

Science.gov (United States)

Janoos, Firdaus; Machiraju, Raghu; Singh, Shantanu; Morocz, Istvan Ákos

2011-07-15

Understanding the highly complex, spatially distributed and temporally organized phenomena entailed by mental processes using functional MRI is an important research problem in cognitive and clinical neuroscience. Conventional analysis methods focus on the spatial dimension of the data discarding the information about brain function contained in the temporal dimension. This paper presents a fully spatio-temporal multivariate analysis method using a state-space model (SSM) for brain function that yields not only spatial maps of activity but also its temporal structure along with spatially varying estimates of the hemodynamic response. Efficient algorithms for estimating the parameters along with quantitative validations are given. A novel low-dimensional feature-space for representing the data, based on a formal definition of functional similarity, is derived. Quantitative validation of the model and the estimation algorithms is provided with a simulation study. Using a real fMRI study for mental arithmetic, the ability of this neurophysiologically inspired model to represent the spatio-temporal information corresponding to mental processes is demonstrated. Moreover, by comparing the models across multiple subjects, natural patterns in mental processes organized according to different mental abilities are revealed. Copyright © 2011 Elsevier Inc. All rights reserved.

Third-order aberration-free ion-optical system for an electromagnetic isotope separator

International Nuclear Information System (INIS)

Chavet, I.

1982-12-01

The essential qualities required of a production isotope separator are high output and high enrichment factor. For this purpose, the imaging system should have as little geometric aberration as possible. In the proposed system, consisting of a homogeneous sector-type analyzing magnet, the beam is crossed in the axial direction at the entrance boundary of the magnetic field and the incidence to this boundary is normal. It is shown that for this case all radial aberrations to the ''practical'' third order can be eliminated provided four optical conditions are satisfied: two related to heterogeneous aberration terms in addition to the two conditions related to the second and third order homogeneous aperture aberration terms. The resulting equations take into account the magnetic fringe-field effects to the third order. (author)

Chromosome aberrations induced by radiation. With special reference to possible relation between chromosome aberrations and carcinogenesis

Energy Technology Data Exchange (ETDEWEB)

Kamada, N [Hiroshima Univ. (Japan). Research Inst. for Nuclear Medicine and Biology

1980-02-01

Chromosome aberration seems to be one of the most conspicuous residual abnormalities recognizable in radiation-exposed persons for many years after exposure. Knowledge of the biological significance of these abnormalities seems to be necessary for understanding of the effect of radiation on humans, especially in relation to possible leukemic development. Cytogenetic studies were performed on the bone marrow cells, T and B lymphocytes, and fibroblasts in atomic bomb-survivors who were in apparent good health (105 cases), atomic bomb exposed patients who had prolonged periods of blood disorders which terminated in acute leukemia (8 cases), and who had no such abnormalities (6 cases). All patients with chronic myelocytic leukemia (CML) and a history of atomic bomb exposure showed Philadelphia chromosome, a characteristic chromosome abnormality for CML. The persistent chromosome aberrations of bone marrow cells, T and B lymphocytes found among the atomic bomb survivors with or without blood disorders may give some clue to solve the problems of carcinogenesis.

Cytogenetic analysis of X-ray induced chromosome aberrations in spontaneous leukaemic AKR mice

International Nuclear Information System (INIS)

Szollar, J.

1975-01-01

The increased frequency of numerical and structural chromosomal aberrations in spontaneously leukaemic AKR mice, compared with the values of healthy control CBA/H-T 6 T 6 mice, induced by X-irradiation, might be connected with the predisposition to malignant growth, probably indirectly helping the virus activation, or acting together with the immune deficiency, by creating a weaker system that is more sensitive to carcinogenic agents

X-ray-induced chromosome aberrations in Down lymphocytes: an explanation of their increased sensitivity

International Nuclear Information System (INIS)

Preston, R.J.

1981-01-01

Unstimulated lymphocytes from individuals with Down Syndrome (trisomy 21) are more sensitive to the induction of dicentric and ring aberrations by X rays than normal lymphocytes. Several explanations involving the more rapid rejoining of X-ray--induced lesions in Down cells have been offered. It is shown here that the repair of the DNA damage converted into chromosome aberrations is more rapid in Down cells than normal cells. This more rapid repair results in a higher probability of producing chromosomes aberrations, and hence higher aberration frequencies in Down than normal cells

X-ray-induced chromosome aberrations in Down lymphocytes: an explanation of their increased sensitivity

International Nuclear Information System (INIS)

Preston, R.J.

1981-01-01

Unstimulated lymphocytes from individuals with Down Syndrome (trisomy 21) are more sensitive to the induction of dicentric and ring aberrations by X rays than normal lymphocytes. Several explanations involving the more rapid rejoining of X-ray-induced lesions in Down cells have been offered. It is shown here that the repair of the DNA damage converted into chromosome aberrations is more rapid in Down cells than normal cells. This more rapid repair results in a higher probability of producing chromosome aberrations, and hence higher aberration frequencies in Down than normal cells

Spatiotemporal dynamics of a digital phase-locked loop based coupled map lattice system

Energy Technology Data Exchange (ETDEWEB)

Banerjee, Tanmoy, E-mail: tbanerjee@phys.buruniv.ac.in; Paul, Bishwajit; Sarkar, B. C. [Department of Physics, University of Burdwan, Burdwan, West Bengal 713 104 (India)

2014-03-15

We explore the spatiotemporal dynamics of a coupled map lattice (CML) system, which is realized with a one dimensional array of locally coupled digital phase-locked loops (DPLLs). DPLL is a nonlinear feedback-controlled system widely used as an important building block of electronic communication systems. We derive the phase-error equation of the spatially extended system of coupled DPLLs, which resembles a form of the equation of a CML system. We carry out stability analysis for the synchronized homogeneous solutions using the circulant matrix formalism. It is shown through extensive numerical simulations that with the variation of nonlinearity parameter and coupling strength the system shows transitions among several generic features of spatiotemporal dynamics, viz., synchronized fixed point solution, frozen random pattern, pattern selection, spatiotemporal intermittency, and fully developed spatiotemporal chaos. We quantify the spatiotemporal dynamics using quantitative measures like average quadratic deviation and spatial correlation function. We emphasize that instead of using an idealized model of CML, which is usually employed to observe the spatiotemporal behaviors, we consider a real world physical system and establish the existence of spatiotemporal chaos and other patterns in this system. We also discuss the importance of the present study in engineering application like removal of clock-skew in parallel processors.

Conventional radiation-biological dosimetry using frequencies of unstable chromosome aberrations

International Nuclear Information System (INIS)

Ramalho, Adriana T.; Costa, Maria Lucia P.; Oliveira, Monica S.

1998-01-01

Frequency of chromosome aberrations detected by conventional cytogenetics is a very useful parameter in biological radiodosimetry. It can be used for estimating absorbed doses in individuals working with radioactive sources and individuals accidentally exposed to radiation. In the first case subjects wear physical dosimeters as a routine safety habit. The laboratory at the Institute of Radioprotection and Dosimetry (IRD, Brazil) has been using conventional cytogenetic analysis to complement data obtained by physical dosimetry since 1983. Until now, more than one hundred cases were investigated where individual physical dosimeters detected occupational exposure (above the safety limits allowed). In total, only 34% of these cases were confirmed by conventional cytogenetic dosimetry. Also, conventional cytogenetic analysis following the radiation accident of Goiania (Brazil) in 1987 have been used. Peripheral lymphocytes from 129 exposed or potentially exposed individuals were analyzed for the frequencies of unstable chromosomal aberrations (dicentrics, centric rings and acentrics fragments) to estimate absorbed radiation doses. During the emergency period, doses were estimated to help immediate medical treatment using in vitro calibration curves produced before the accident. Later on, doses were assessed once more using new in vitro calibration curves. A drawback of this technique is that unstable aberrations are lost after exposure. To investigate the mean lifespan of lymphocytes containing dicentric and ring aberrations, we have followed 15 victims of the Goiania accident over all these years. Results suggest that the disappearance of unstable aberrations is dose-dependent. This could explain the variation in the results found among studies in this field

Conventional radiation-biological dosimetry using frequencies of unstable chromosome aberrations

Energy Technology Data Exchange (ETDEWEB)

Ramalho, Adriana T.; Costa, Maria Lucia P.; Oliveira, Monica S. [Institute of Radioprotection and Dosimetry (IRD), National Commission of Nuclear Energy (CNEN), Av. Salvador Allende, Cx. P. 37750, Rio de Janeiro 22.780-160 (Brazil)

1998-08-03

Frequency of chromosome aberrations detected by conventional cytogenetics is a very useful parameter in biological radiodosimetry. It can be used for estimating absorbed doses in individuals working with radioactive sources and individuals accidentally exposed to radiation. In the first case subjects wear physical dosimeters as a routine safety habit. The laboratory at the Institute of Radioprotection and Dosimetry (IRD, Brazil) has been using conventional cytogenetic analysis to complement data obtained by physical dosimetry since 1983. Until now, more than one hundred cases were investigated where individual physical dosimeters detected occupational exposure (above the safety limits allowed). In total, only 34% of these cases were confirmed by conventional cytogenetic dosimetry. Also, conventional cytogenetic analysis following the radiation accident of Goiania (Brazil) in 1987 have been used. Peripheral lymphocytes from 129 exposed or potentially exposed individuals were analyzed for the frequencies of unstable chromosomal aberrations (dicentrics, centric rings and acentrics fragments) to estimate absorbed radiation doses. During the emergency period, doses were estimated to help immediate medical treatment using in vitro calibration curves produced before the accident. Later on, doses were assessed once more using new in vitro calibration curves. A drawback of this technique is that unstable aberrations are lost after exposure. To investigate the mean lifespan of lymphocytes containing dicentric and ring aberrations, we have followed 15 victims of the Goiania accident over all these years. Results suggest that the disappearance of unstable aberrations is dose-dependent. This could explain the variation in the results found among studies in this field

A new aberration-corrected, energy-filtered LEEM/PEEM instrument. I. Principles and design

International Nuclear Information System (INIS)

Tromp, R.M.; Hannon, J.B.; Ellis, A.W.; Wan, W.; Berghaus, A.; Schaff, O.

2010-01-01

We describe a new design for an aberration-corrected low energy electron microscope (LEEM) and photo electron emission microscope (PEEM), equipped with an in-line electron energy filter. The chromatic and spherical aberrations of the objective lens are corrected with an electrostatic electron mirror that provides independent control over the chromatic and spherical aberration coefficients C c and C 3 , as well as the mirror focal length, to match and correct the aberrations of the objective lens. For LEEM (PEEM) the theoretical resolution is calculated to be ∼1.5 nm (∼4 nm). Unlike previous designs, this instrument makes use of two magnetic prism arrays to guide the electron beam from the sample to the electron mirror, removing chromatic dispersion in front of the mirror by symmetry. The aberration correction optics was retrofitted to an uncorrected instrument with a base resolution of 4.1 nm in LEEM. Initial results in LEEM show an improvement in resolution to ∼2 nm.

Heavy ion-induced chromosomal aberrations analyzed by fluorescence in situ hybridization

International Nuclear Information System (INIS)

Durante, M.; Gialanella, G.; Grossi, G.; Pugliese, M.; Cella, L.; Greco, O.; George, K.; Yang, T.C.

1997-01-01

We have investigated the effectiveness of heavy ions in the induction of chromosomal aberrations in mammalian cells by the recent technique of fluorescence in situ hybridization (FISH) with whole-chromosome probes. FISH-painting was used both in metaphase and interphase (prematurely condensed) chromosomes. The purpose of our experiments was to address the following problems: (a) the ratio of different types of aberrations as a function of radiation quality (search for biomarkers); (b) the ratio between aberrations scored in interphase and metaphase as a function of radiation quality (role of apoptosis); (c) differences between cytogenetic effects produced by different ions at the same LET (role of track structure). (orig./MG)

Heavy ion-induced chromosomal aberrations analyzed by fluorescence in situ hybridization

Energy Technology Data Exchange (ETDEWEB)

Durante, M; Gialanella, G; Grossi, G; Pugliese, M [Univ. ` ` Federico II` ` , Naples (Italy). Dept. of Physics; [INFN, Naples (Italy); Cella, L; Greco, O [Univ. ` ` Federico II` ` , Naples (Italy). Dept. of Physics; Furusawa, Y [NIRS, Chiba (Japan); George, K; Yang, T C [NASA Lyndon B. Johnson Space Center, Houston, TX (United States)

1997-09-01

We have investigated the effectiveness of heavy ions in the induction of chromosomal aberrations in mammalian cells by the recent technique of fluorescence in situ hybridization (FISH) with whole-chromosome probes. FISH-painting was used both in metaphase and interphase (prematurely condensed) chromosomes. The purpose of our experiments was to address the following problems: (a) the ratio of different types of aberrations as a function of radiation quality (search for biomarkers); (b) the ratio between aberrations scored in interphase and metaphase as a function of radiation quality (role of apoptosis); (c) differences between cytogenetic effects produced by different ions at the same LET (role of track structure). (orig./MG)

Intraoperative non-record-keeping usage of anesthesia information management system workstations and associated hemodynamic variability and aberrancies.

Science.gov (United States)

Wax, David B; Lin, Hung-Mo; Reich, David L

2012-12-01

Anesthesia information management system workstations in the anesthesia workspace that allow usage of non-record-keeping applications could lead to distraction from patient care. We evaluated whether non-record-keeping usage of the computer workstation was associated with hemodynamic variability and aberrancies. Auditing data were collected on eight anesthesia information management system workstations and linked to their corresponding electronic anesthesia records to identify which application was active at any given time during the case. For each case, the periods spent using the anesthesia information management system record-keeping module were separated from those spent using non-record-keeping applications. The variability of heart rate and blood pressure were also calculated, as were the incidence of hypotension, hypertension, and tachycardia. Analysis was performed to identify whether non-record-keeping activity was a significant predictor of these hemodynamic outcomes. Data were analyzed for 1,061 cases performed by 171 clinicians. Median (interquartile range) non-record-keeping activity time was 14 (1, 38) min, representing 16 (3, 33)% of a median 80 (39, 143) min of procedure time. Variables associated with greater non-record-keeping activity included attending anesthesiologists working unassisted, longer case duration, lower American Society of Anesthesiologists status, and general anesthesia. Overall, there was no independent association between non-record-keeping workstation use and hemodynamic variability or aberrancies during anesthesia either between cases or within cases. Anesthesia providers spent sizable portions of case time performing non-record-keeping applications on anesthesia information management system workstations. This use, however, was not independently associated with greater hemodynamic variability or aberrancies in patients during maintenance of general anesthesia for predominantly general surgical and gynecologic procedures.

Chromosomal Aberrations in Monozygotic and Dizygotic Twins Versus Singletons in Denmark During 1968-2009

DEFF Research Database (Denmark)

Kristensen, Lone Krøldrup; Larsen, Lisbeth A; Fagerberg, Christina

2017-01-01

BACKGROUND: Hall (Embryologic development and monozygotic twinning. Acta Geneticae Medicae et Gemellologiae, Vol. 45, 1996, pp. 53-57) hypothesized that chromosomal aberrations can lead to monozygotic (MZ) twinning. However, twinning and chromosomal aberrations increase prenatal mortality and could...... reduce the prevalence of chromosomal aberrations in live-born twins. We compared prevalence proportion ratios (PPR) of chromosomal aberrations and trisomy 21 (T21) in live-born twins versus singletons born in Denmark during 1968-2009. METHODS: We linked the Danish Twin Registry and a 5% random sample...... of all singletons to the Danish Cytogenetic Central Register and calculated PPR adjusted for maternal age for MZ, dizygotic (DZ), and all twins versus singletons. Zygosity was based on questionnaires or genetic markers. RESULTS: No overall difference in risk of chromosomal aberrations or T21 in twins...

In vivo chromatic aberration in eyes implanted with intraocular lenses.

Science.gov (United States)

Pérez-Merino, Pablo; Dorronsoro, Carlos; Llorente, Lourdes; Durán, Sonia; Jiménez-Alfaro, Ignacio; Marcos, Susana

2013-04-12

To measure in vivo and objectively the monochromatic aberrations at different wavelengths, and the chromatic difference of focus between green and infrared wavelengths in eyes implanted with two models of intraocular lenses (IOL). EIGHTEEN EYES PARTICIPATED IN THIS STUDY: nine implanted with Tecnis ZB99 1-Piece acrylic IOL and nine implanted with AcrySof SN60WF IOL. A custom-developed laser ray tracing (LRT) aberrometer was used to measure the optical aberrations, at 532 nm and 785 nm wavelengths. The monochromatic wave aberrations were described using a fifth-order Zernike polynomial expansion. The chromatic difference of focus was estimated as the difference between the equivalent spherical errors corresponding to each wavelength. Wave aberration measurements were highly reproducible. Except for the defocus term, no significant differences in high order aberrations (HOA) were found between wavelengths. The average chromatic difference of focus was 0.46 ± 0.15 diopters (D) in the Tecnis group, and 0.75 ± 0.12 D in the AcrySof group, and the difference was statistically significant (P Chromatic difference of focus in the AcrySof group was not statistically significantly different from the Longitudinal chromatic aberration (LCA) previously reported in a phakic population (0.78 ± 0.16 D). The impact of LCA on retinal image quality (measured in terms of Strehl ratio) was drastically reduced when considering HOA and astigmatism in comparison with a diffraction-limited eye, yielding the differences in retinal image quality between Tecnis and AcrySof IOLs not significant. LRT aberrometry at different wavelengths is a reproducible technique to evaluate the chromatic difference of focus objectively in eyes implanted with IOLs. Replacement of the crystalline lens by the IOL did not increase chromatic difference of focus above that of phakic eyes in any of the groups. The AcrySof group showed chromatic difference of focus values very similar to physiological values in

Aberrant neuromagnetic activation in the motor cortex in children with acute migraine: a magnetoencephalography study.

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Xinyao Guo

Full Text Available Migraine attacks have been shown to interfere with normal function in the brain such as motor or sensory function. However, to date, there has been no clinical neurophysiology study focusing on the motor function in children with migraine during headache attacks. To investigate the motor function in children with migraine, twenty-six children with acute migraine, meeting International Classification of Headache Disorders criteria and age- and gender-matched healthy children were studied using a 275-channel magnetoencephalography system. A finger-tapping paradigm was designed to elicit neuromagnetic activation in the motor cortex. Children with migraine showed significantly prolonged latency of movement-evoked magnetic fields (MEF during finger movement compared with the controls. The correlation coefficient of MEF latency and age in children with migraine was significantly different from that in healthy controls. The spectral power of high gamma (65-150 Hz oscillations during finger movement in the primary motor cortex is also significantly higher in children with migraine than in controls. The alteration of responding latency and aberrant high gamma oscillations suggest that the developmental trajectory of motor function in children with migraine is impaired during migraine attacks and/or developmentally delayed. This finding indicates that childhood migraine may affect the development of brain function and result in long-term problems.

Effect of correction of aberration dynamics on chaos in human ocular accommodation.

Science.gov (United States)

Hampson, Karen M; Cufflin, Matthew P; Mallen, Edward A H

2013-11-15

We used adaptive optics to determine the effect of monochromatic aberration dynamics on the level of chaos in the accommodation control system. Four participants viewed a stationary target while the dynamics of their aberrations were either left uncorrected, defocus was corrected, or all aberrations except defocus were corrected. Chaos theory analysis was used to discern changes in the accommodative microfluctuations. We found a statistically significant reduction in the chaotic nature of the accommodation microfluctuations during correction of defocus, but not when all aberrations except defocus were corrected. The Lyapunov exponent decreased from 0.71 ± 0.07 D/s (baseline) to 0.55 ± 0.03 D/s (correction of defocus fluctuations). As the reduction of chaos in physiological signals is indicative of stress to the system, the results indicate that for the participants included in this study, fluctuations in defocus have a more profound effect than those of the other aberrations. There were no changes in the power spectrum between experimental conditions. Hence chaos theory analysis is a more subtle marker of changes in the accommodation control system and will be of value in the study of myopia onset and progression.

Axial geometrical aberration correction up to 5th order with N-SYLC.

Science.gov (United States)

Hoque, Shahedul; Ito, Hiroyuki; Takaoka, Akio; Nishi, Ryuji

2017-11-01

We present N-SYLC (N-fold symmetric line currents) models to correct 5th order axial geometrical aberrations in electron microscopes. In our previous paper, we showed that 3rd order spherical aberration can be corrected by 3-SYLC doublet. After that, mainly the 5th order aberrations remain to limit the resolution. In this paper, we extend the doublet to quadruplet models also including octupole and dodecapole fields for correcting these higher order aberrations, without introducing any new unwanted ones. We prove the validity of our models by analytical calculations. Also by computer simulations, we show that for beam energy of 5keV and initial angle 10mrad at the corrector object plane, beam size of less than 0.5nm is achieved at the corrector image plane. Copyright © 2017 Elsevier B.V. All rights reserved.

Gametocidal chromosomes enhancing chromosome aberration in common wheat induced by 5-azacytidine.

Science.gov (United States)

Su, W-Y; Cong, W-W; Shu, Y-J; Wang, D; Xu, G-H; Guo, C-H

2013-07-08

The gametocidal (Gc) chromosome from Aegilops spp induces chromosome mutation, which is introduced into common wheat as a tool of chromosome manipulation for genetic improvement. The Gc chromosome functions similar to a restriction-modification system in bacteria, in which DNA methylation is an important regulator. We treated root tips of wheat carrying Gc chromosomes with the hypomethylation agent 5-azacytidine; chromosome breakage and micronuclei were observed in these root tips. The frequency of aberrations differed in wheat containing different Gc chromosomes, suggesting different functions inducing chromosome breakage. Gc chromosome 3C caused the greatest degree of chromosome aberration, while Gc chromosome 3C(SAT) and 2C caused only slight chromosome aberration. Gc chromosome 3C induced different degrees of chromosome aberration in wheat varieties Triticum aestivum var. Chinese Spring and Norin 26, demonstrating an inhibition function in common wheat.

Neural avalanches at the critical point between replay and non-replay of spatiotemporal patterns.

Directory of Open Access Journals (Sweden)

Silvia Scarpetta

Full Text Available We model spontaneous cortical activity with a network of coupled spiking units, in which multiple spatio-temporal patterns are stored as dynamical attractors. We introduce an order parameter, which measures the overlap (similarity between the activity of the network and the stored patterns. We find that, depending on the excitability of the network, different working regimes are possible. For high excitability, the dynamical attractors are stable, and a collective activity that replays one of the stored patterns emerges spontaneously, while for low excitability, no replay is induced. Between these two regimes, there is a critical region in which the dynamical attractors are unstable, and intermittent short replays are induced by noise. At the critical spiking threshold, the order parameter goes from zero to one, and its fluctuations are maximized, as expected for a phase transition (and as observed in recent experimental results in the brain. Notably, in this critical region, the avalanche size and duration distributions follow power laws. Critical exponents are consistent with a scaling relationship observed recently in neural avalanches measurements. In conclusion, our simple model suggests that avalanche power laws in cortical spontaneous activity may be the effect of a network at the critical point between the replay and non-replay of spatio-temporal patterns.

Use of M-FISH analysis of α-particle-induced chromosome aberrations for the assessment of chromosomal breakpoint distribution and complex aberration formation

International Nuclear Information System (INIS)

Anderson, R.M.; Sumption, N.D.; Papworth, D.G.; Goodhead, D.T.

2003-01-01

Double strand breaks (dsb) of varying complexity are an important class of damage induced after exposure to ionising radiation and are considered to be the critical lesion for the formation of radiation-induced chromosome aberrations. Assuming the basic principles of the 'Breakage and Reunion' theory, dsb represent 'breakage' and aberrations are produced from the illegitimate repair (reunion) of the resulting dsb free-'ends'. Numerous questions relate to this process, in particular, (1) do chromosomal breakpoint 'hot-spots' that represent sensitive sites for breakage and/or regions of preferential repair/mis-repair, exist? (2) Considering that individual chromosomes and chromosome regions occupy discrete territories in the interphase nucleus, could rearrangements between specific chromosomes reflect domain organisation at the time of damage? (3) Assuming the topological constraints imposed on chromatin are not dramatically influenced by the presence of dsb, then how do multiple 'ends' from different chromosomes proximally associate for mis-repair as complex chromosome aberrations? To address these questions, we have analysed the chromosome aberrations induced in peripheral blood lymphocytes after exposure to 0.5 Gy α -particles (mean of 1 α -particle/cell) using the technique of M-FISH. This technique 'paints' all the human chromosomes (excluding homologues) uniquely, allowing chromosomal mis-repair to be visualised as differential colour-junctions and in addition, enhanced DAPI banding enables gross breakpoint assignation of these colour junctions. To test for non-randomness, we are comparing the frequency of occurrence of breakpoints obtained up to now with the F98 glioma model our knowledbased on chromosome length. Similarly, the involvement of each chromosome relative to other chromosomes within individual rearrangements can be determined by assuming the volume of chromosome domains is also proportional to their length. The current data to be presented will

High-resolution TEM and the application of direct and indirect aberration correction

DEFF Research Database (Denmark)

Hetherington, Crispin J.D.; Chang, Lan-Yun Shery; Haigh, Sarah

2008-01-01

Aberration correction leads to a substantial improvement in the directly interpretable resolution of transmission electron microscopes. Correction of the aberrations has been achieved electron-optically through a hexapole-based corrector and also indirectly by computational analysis of a focal or...

Effect of third-order aberrations on dynamic accommodation.

Science.gov (United States)

López-Gil, Norberto; Rucker, Frances J; Stark, Lawrence R; Badar, Mustanser; Borgovan, Theodore; Burke, Sean; Kruger, Philip B

2007-03-01

We investigate the potential for the third-order aberrations coma and trefoil to provide a signed cue to accommodation. It is first demonstrated theoretically (with some assumptions) that the point spread function is insensitive to the sign of spherical defocus in the presence of odd-order aberrations. In an experimental investigation, the accommodation response to a sinusoidal change in vergence (1-3D, 0.2Hz) of a monochromatic stimulus was obtained with a dynamic infrared optometer. Measurements were obtained in 10 young visually normal individuals with and without custom contact lenses that induced low and high values of r.m.s. trefoil (0.25, 1.03 microm) and coma (0.34, 0.94 microm). Despite variation between subjects, we did not find any statistically significant increase or decrease in the accommodative gain for low levels of trefoil and coma, although effects approached or reached significance for the high levels of trefoil and coma. Theoretical and experimental results indicate that the presence of Zernike third-order aberrations on the eye does not seem to play a crucial role in the dynamics of the accommodation response.

Test for Chemical Induction of Chromosome Aberration in Cultured Chinese Hamster Ovary (CHO) Cells With and Without Metabolic Activation. Test Article: N,N,N’,N’-tetramethyl Ethanediamine (TMEDA)

Science.gov (United States)

2008-06-13

the RCG and/or RMI: ill addition, the percentage of polyploid and endoreduplicated cells was also determined at each concentration. Both the solvent...percentage of polyploid and endoreduplicated cells was also determined at each concentration. The types of chromosome aberrations scored and the...not decipherable. Considered as a single aberration. Severely damaged cell - cell with 10 or more aberrations. Polyploid cells - metaphases with

High early life stress and aberrant amygdala activity: risk factors for elevated neuropsychiatric symptoms in HIV+ adults.

Science.gov (United States)

Clark, Uraina S; Sweet, Lawrence H; Morgello, Susan; Philip, Noah S; Cohen, Ronald A

2017-06-01

Relative to HIV-negative adults, HIV+ adults report elevated levels of early life stress (ELS). In non-HIV samples, high ELS has been linked to abnormalities in brain structure and function, as well as increased risk of neuropsychiatric symptoms. Yet, little is known about the neural effects of high ELS, and their relation to elevated neuropsychiatric symptoms, in HIV+ adults. Recent studies have revealed combined effects of HIV and high ELS on amygdala morphometry. Aberrant amygdala activity is prominently implicated in studies of neuropsychiatric symptomology in non-HIV samples. Hence, this preliminary study examined: 1) the combined effects of HIV and high ELS on amygdala activity, and 2) the relation between amygdala activity and neuropsychiatric symptoms in HIV+ adults. We included 28 HIV+ adults and 25 demographically-matched HIV-negative control (HC) adults. ELS exposure was quantified using a retrospective ELS questionnaire, which defined four groups: HIV+ Low-ELS (N = 15); HIV+ High-ELS (N = 13); HC Low-ELS (N = 16); and HC High-ELS (N = 9). Participants completed a battery of neuropsychiatric measures. BOLD fMRI assessed amygdala reactivity during explicit observation of fearful/angry faces. High-ELS participants demonstrated reduced levels of amygdala reactivity relative to Low-ELS participants. HIV+ High-ELS participants reported higher levels of neuropsychiatric symptoms than all other groups. In the HIV+ group, lower amygdala responses were associated with higher neuropsychiatric symptoms, particularly depression, anxiety, and alexithymia. Collectively, these results suggest that high ELS exposure is a significant risk factor for neuropsychiatric symptoms in HIV+ adults. Furthermore, our results implicate ELS-related abnormalities in amygdala activity in the etiology of neuropsychiatric symptoms in HIV+ adults.

Selective corneal optical aberration (SCOA) for customized ablation

Science.gov (United States)

Jean, Benedikt J.; Bende, Thomas

2001-06-01

Wavefront analysis still have some technical problems which may be solved within the next years. There are some limitations to use wavefront as a diagnostic tool for customized ablation alone. An ideal combination would be wavefront and topography. Meanwhile Selective Corneal Aberration is a method to visualize the optical quality of a measured corneal surface. It is based on a true measured 3D elevation information of a video topometer. Thus values can be interpreted either using Zernike polynomials or visualized as a so called color coded surface quality map. This map gives a quality factor (corneal aberration) for each measured point of the cornea.

Static telescope aberration measurement using lucky imaging techniques

Science.gov (United States)

López-Marrero, Marcos; Rodríguez-Ramos, Luis Fernando; Marichal-Hernández, José Gil; Rodríguez-Ramos, José Manuel

2012-07-01

A procedure has been developed to compute static aberrations once the telescope PSF has been measured with the lucky imaging technique, using a nearby star close to the object of interest as the point source to probe the optical system. This PSF is iteratively turned into a phase map at the pupil using the Gerchberg-Saxton algorithm and then converted to the appropriate actuation information for a deformable mirror having low actuator number but large stroke capability. The main advantage of this procedure is related with the capability of correcting static aberration at the specific pointing direction and without the need of a wavefront sensor.

Spatio-temporal data analytics for wind energy integration

CERN Document Server

Yang, Lei; Zhang, Junshan

2014-01-01

This SpringerBrief presents spatio-temporal data analytics for wind energy integration using stochastic modeling and optimization methods. It explores techniques for efficiently integrating renewable energy generation into bulk power grids. The operational challenges of wind, and its variability are carefully examined. A spatio-temporal analysis approach enables the authors to develop Markov-chain-based short-term forecasts of wind farm power generation. To deal with the wind ramp dynamics, a support vector machine enhanced Markov model is introduced. The stochastic optimization of economic di

Spatiotemporal patterns and predictability of cyberattacks.

Directory of Open Access Journals (Sweden)

Yu-Zhong Chen

Full Text Available A relatively unexplored issue in cybersecurity science and engineering is whether there exist intrinsic patterns of cyberattacks. Conventional wisdom favors absence of such patterns due to the overwhelming complexity of the modern cyberspace. Surprisingly, through a detailed analysis of an extensive data set that records the time-dependent frequencies of attacks over a relatively wide range of consecutive IP addresses, we successfully uncover intrinsic spatiotemporal patterns underlying cyberattacks, where the term "spatio" refers to the IP address space. In particular, we focus on analyzing macroscopic properties of the attack traffic flows and identify two main patterns with distinct spatiotemporal characteristics: deterministic and stochastic. Strikingly, there are very few sets of major attackers committing almost all the attacks, since their attack "fingerprints" and target selection scheme can be unequivocally identified according to the very limited number of unique spatiotemporal characteristics, each of which only exists on a consecutive IP region and differs significantly from the others. We utilize a number of quantitative measures, including the flux-fluctuation law, the Markov state transition probability matrix, and predictability measures, to characterize the attack patterns in a comprehensive manner. A general finding is that the attack patterns possess high degrees of predictability, potentially paving the way to anticipating and, consequently, mitigating or even preventing large-scale cyberattacks using macroscopic approaches.

Protein Tyrosine Phosphatase-PEST and β8 Integrin Regulate Spatiotemporal Patterns of RhoGDI1 Activation in Migrating Cells

Science.gov (United States)

Lee, Hye Shin; Cheerathodi, Mujeeburahiman; Chaki, Sankar P.; Reyes, Steve B.; Zheng, Yanhua; Lu, Zhimin; Paidassi, Helena; DerMardirossian, Celine; Lacy-Hulbert, Adam; Rivera, Gonzalo M.

2015-01-01

Directional cell motility is essential for normal development and physiology, although how motile cells spatiotemporally activate signaling events remains largely unknown. Here, we have characterized an adhesion and signaling unit comprised of protein tyrosine phosphatase (PTP)-PEST and the extracellular matrix (ECM) adhesion receptor β8 integrin that plays essential roles in directional cell motility. β8 integrin and PTP-PEST form protein complexes at the leading edge of migrating cells and balance patterns of Rac1 and Cdc42 signaling by controlling the subcellular localization and phosphorylation status of Rho GDP dissociation inhibitor 1 (RhoGDI1). Translocation of Src-phosphorylated RhoGDI1 to the cell's leading edge promotes local activation of Rac1 and Cdc42, whereas dephosphorylation of RhoGDI1 by integrin-bound PTP-PEST promotes RhoGDI1 release from the membrane and sequestration of inactive Rac1/Cdc42 in the cytoplasm. Collectively, these data reveal a finely tuned regulatory mechanism for controlling signaling events at the leading edge of directionally migrating cells. PMID:25666508

A monochromatic, aberration-corrected, dual-beam low energy electron microscope.

Science.gov (United States)

Mankos, Marian; Shadman, Khashayar

2013-07-01

The monochromatic, aberration-corrected, dual-beam low energy electron microscope (MAD-LEEM) is a novel instrument aimed at imaging of nanostructures and surfaces at sub-nanometer resolution that includes a monochromator, aberration corrector and dual beam illumination. The monochromator reduces the energy spread of the illuminating electron beam, which significantly improves spectroscopic and spatial resolution. The aberration corrector utilizes an electron mirror with negative aberrations that can be used to compensate the aberrations of the LEEM objective lens for a range of electron energies. Dual flood illumination eliminates charging generated when a conventional LEEM is used to image insulating specimens. MAD-LEEM is designed for the purpose of imaging biological and insulating specimens, which are difficult to image with conventional LEEM, Low-Voltage SEM, and TEM instruments. The MAD-LEEM instrument can also be used as a general purpose LEEM with significantly improved resolution. The low impact energy of the electrons is critical for avoiding beam damage, as high energy electrons with keV kinetic energies used in SEMs and TEMs cause irreversible change to many specimens, in particular biological materials. A potential application for MAD-LEEM is in DNA sequencing, which demands imaging techniques that enable DNA sequencing at high resolution and speed, and at low cost. The key advantages of the MAD-LEEM approach for this application are the low electron impact energies, the long read lengths, and the absence of heavy-atom DNA labeling. Image contrast simulations of the detectability of individual nucleotides in a DNA strand have been developed in order to refine the optics blur and DNA base contrast requirements for this application. Copyright © 2013 Elsevier B.V. All rights reserved.

Reduction of coating induced polarization aberrations by controlling the polarization state variation

International Nuclear Information System (INIS)

Li, Yanghui; Shen, Weidong; Zheng, Zhenrong; Zhang, Yueguang; Liu, Xu; Hao, Xiang

2011-01-01

The mechanism of coating induced polarization state variation is analysed by the Jones matrix. Pauli spin matrices are used to establish the relationship between coating induced polarization state variation and polarization aberrations. To reduce coating induced polarization aberrations, we propose that δ = 0 and T s = T p at arbitrary incident angle should be appended as two additional optimization goals of optical coating design when the requirements of transmittance are met. Two typical anti-reflection (AR) coatings are designed and the polarization state variation induced by them is simulated. The MTF (modulation transfer function) calculated by polarization ray tracing is applied to evaluate the polarization aberrations of the practical lithography objective system with the two AR coatings. All the obtained results show that the coating induced polarization aberrations can be reduced by optimizing the angle dependent properties of the optical coating without additional optical elements

Chromosome aberrations of bone marrow cells in heavily exposed atomic bomb survivors

International Nuclear Information System (INIS)

Tanaka, Kimio; Kamada, Nanao; Kuramoto, Atsushi; Ohkita, Takeshi

1986-01-01

Seven hundred and ten bone marrow cells from 13 A-bomb survivors, who were heavily exposed to atomic radiation, were examined using chromosome banding method. An average frequency of chromosome aberrations was 17 %. The most common structural abnormality was translocation (47 %), followed by complex aberrations involving three or more chromosomes (32 %). These abnormalities were frequently seen in A-bomb survivors exposed to estimated doses of 3.5 - 4.0 Gy. Eighty two percent of the structural aberrations were stable. Diploid cells were seen in 0.4 % and tetraploid cells were seen in 0.7 %. The frequency of breakpoint sites was high in chromosomes 1 and 17; while it was low in chromosomes 3, 6, 9, and 11. Abnormal clones were seen in one of the 13 survivors. Chromosome aberrations common to the bone marrow cells and peripheral lymphocytes were not seen in the same individual. (Namekawa, K.)

Aberrant ovarian artery arising from the common Iliac artery: Case report

Energy Technology Data Exchange (ETDEWEB)

Kim, Won Kyung [Dept. of Radiology, Soonchunhyang University Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon (Korea, Republic of); Yang, Seung Boo; Lee, Jae Myeong [Dept. of Radiology, Soonchunhyang University Gumi Hospital, Soonchunhyang University College of Medicine, Gumi (Korea, Republic of); Goo, Dong Erk; Kim, Yong Jae; Chang, Yun Woo [Dept. of Radiology, Soonchunhyang University Seoul Hospital, Soonchunhyang University College of Medicine, Seoul (Korea, Republic of)

2013-01-15

A 46-year-old Vietnamese woman received embolization therapy in order to control postpartum hemorrhage. Angiography revealed an aberrant ovarian artery arising from the right common iliac artery. Superselective catheterization and subsequent embolization of the aberrant ovarian artery and bilateral uterine arteries were performed. Precise knowledge of the anatomic variations of the ovarian artery is important for successful embolization.

Aberrant ovarian artery arising from the common Iliac artery: Case report

International Nuclear Information System (INIS)

Kim, Won Kyung; Yang, Seung Boo; Lee, Jae Myeong; Goo, Dong Erk; Kim, Yong Jae; Chang, Yun Woo

2013-01-01

A 46-year-old Vietnamese woman received embolization therapy in order to control postpartum hemorrhage. Angiography revealed an aberrant ovarian artery arising from the right common iliac artery. Superselective catheterization and subsequent embolization of the aberrant ovarian artery and bilateral uterine arteries were performed. Precise knowledge of the anatomic variations of the ovarian artery is important for successful embolization.

Measuring higher order optical aberrations of the human eye: techniques and applications

Directory of Open Access Journals (Sweden)

L. Alberto V. Carvalho

2002-11-01

Full Text Available In the present paper we discuss the development of "wave-front", an instrument for determining the lower and higher optical aberrations of the human eye. We also discuss the advantages that such instrumentation and techniques might bring to the ophthalmology professional of the 21st century. By shining a small light spot on the retina of subjects and observing the light that is reflected back from within the eye, we are able to quantitatively determine the amount of lower order aberrations (astigmatism, myopia, hyperopia and higher order aberrations (coma, spherical aberration, etc.. We have measured artificial eyes with calibrated ametropia ranging from +5 to -5 D, with and without 2 D astigmatism with axis at 45º and 90º. We used a device known as the Hartmann-Shack (HS sensor, originally developed for measuring the optical aberrations of optical instruments and general refracting surfaces in astronomical telescopes. The HS sensor sends information to a computer software for decomposition of wave-front aberrations into a set of Zernike polynomials. These polynomials have special mathematical properties and are more suitable in this case than the traditional Seidel polynomials. We have demonstrated that this technique is more precise than conventional autorefraction, with a root mean square error (RMSE of less than 0.1 µm for a 4-mm diameter pupil. In terms of dioptric power this represents an RMSE error of less than 0.04 D and 5º for the axis. This precision is sufficient for customized corneal ablations, among other applications.

Scaling laws for aberrations in magnetic quadrupole lens systems

International Nuclear Information System (INIS)

Moses, R.W.; Heighway, E.A.; Christian, R.S.; Dragt, A.J.

1987-01-01

A comparison has been made of the third-order (spherical) abberrations in magnetic quadrupole lenses for use in conventional charged particle beam transport systems. An analytical description of the abberrations is presented and this is compared with the results of high order numerical integration. The dependence of the aberration strength on the system geometry and f number is given and a comparison of doublet and triplet systems made. The reduction of the aberrations in both doublet and triplet systems using embedded magnetic octupole lenses is also discussed and analytical predictions are given

Papillary carcinoma in median aberrant thyroid (ectopic) - case report.

Science.gov (United States)

Hebbar K, Ashwin; K, Shashidhar; Deshmane, Vijaya Laxmi; Kumar, Veerendra; Arjunan, Ravi

2014-06-01

Median ectopic thyroid may be encountered anywhere from the foramen caecum to the diaphragm. Non lingual median aberrant thyroid (incomplete descent) usually found in the infrahyoid region and malignant transformation in this ectopic thyroid tissue is very rare. We report an extremely rare case of papillary carcinoma in non lingual median aberrant thyroid in a 25-year-old female. The differentiation between a carcinoma arising in the median ectopic thyroid tissue and a metastatic papillary carcinoma from an occult primary in the main thyroid gland is also discussed.

Comparison of monochromatic aberrations in young adults with different visual acuity and refractive errors.

Science.gov (United States)

Yazar, Seyhan; Hewitt, Alex W; Forward, Hannah; McKnight, Charlotte M; Tan, Alex; Mountain, Jenny A; Mackey, David A

2014-03-01

To compare the monochromatic aberrations in a large cohort of 20-year-old Australians with differing levels of visual acuity and explore the relationship between these aberrations and refractive error. Lions Eye Institute, Perth, Western Australia, Australia. Cross-sectional analysis of a population-based cohort. Monochromatic aberrations were measured using a Zywave II wavefront aberrometer with natural pupils in a dark room. The logMAR corrected distance visual acuity (CDVA) was measured monocularly under normal illumination. Cycloplegic autorefraction was also performed. The study enrolled 2039 eyes of 1040 participants. Data from 1007 right eyes were analyzed. The median CDVA and spherical equivalent were -0.06 logMAR (interquartile range [IQR], -0.10 to 0.00) and +0.25 diopters (D) (IQR, -0.38 to 0.63), respectively. The median 6.0 mm higher-order aberration (HOA) was 0.58 μm (IQR, 0.44 to 0.79). Coma-like aberrations and 3rd-, 4th-, and 5th-order HOAs were significantly different between subjects with a CDVA of -0.10 logMAR or better and those with a CDVA worse than -0.10 logMAR. Fourth-order aberrations Z(4,-4) (P=.024) and Z(4,-2) (P=.029) and 2nd-order aberration Z(2,0) (Peyes, emmetropic eyes, and hyperopic eyes. Subjects with higher myopia had slightly higher total HOAs. The HOAs in this population were marginally higher than previously reported values. The findings confirm there is a difference in monochromatic aberrations between different vision and refractive groups. Results in this study will benefit decision-making processes in the clinical setting. Copyright © 2014 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Intrinsic factors that can affect sensitivity to chromosome-aberration induction

International Nuclear Information System (INIS)

Preston, R.J.

1982-01-01

The paper addresses the question, are there individuals who are hypersensitive, or are more likely to be hypersensitive, to the induction of chromosome aberrations by radiation and chemicals. Lymphocytes of persons heterozygous for xeroderma pigmentosum, ataxia telangiectasia, and Fauconi's anemia were subjected to chemical and/or ionizing radiations to determine their sensitivity to chromosome aberration induction. In the majority of cases the sensitivity was intermediate between that of normal individuals and homozygotes for these genes

Compensation of aberrations of deflected electron probe by means of dynamical focusing with stigmator

International Nuclear Information System (INIS)

Baba, Norio; Ebe, Toyoe; Ikehata, Koichi; Ito, Yasuhiro; Terada, Hiroshi

1979-01-01

Electron beam passing through a deflecting field is in general, subjected to aberrations such as distortion, astigmatism and coma in accordance with the deflecting angle. Accordingly the aberration defect of deflected beam is the most serious limiting factor in the performances of micromachining, microminiaturization and high resolution scanning electron microscopes. From many investigators' results, it is obvious that three important compensation methods to aberrations exist in principle, i.e., double deflection system, dynamical focusing, and the dynamical correction using a stigmator. In this paper, based on the aberration formula derived from the eikonal or the path method, the practical data of the aberration constants of deflected electron beam for the sequential deflection system with parallel plates are calculated, and using its result, the distorted spot patterns of an electron probe deflected in two-dimensional directions for various defocusings are graphically displayed by the aid of a computer. Further, by means of the dynamical focusing with a stigmator, the conditions to completely compensate the second order astigmatic aberration are derived, and spot patterns and the electron density distributions within the spots in the case when the compensating conditions are satisfied are also graphically displayed. (Wakatsuki, Y.)

Research of Cadastral Data Modelling and Database Updating Based on Spatio-temporal Process

Directory of Open Access Journals (Sweden)

ZHANG Feng

2016-02-01

Full Text Available The core of modern cadastre management is to renew the cadastre database and keep its currentness,topology consistency and integrity.This paper analyzed the changes and their linkage of various cadastral objects in the update process.Combined object-oriented modeling technique with spatio-temporal objects' evolution express,the paper proposed a cadastral data updating model based on the spatio-temporal process according to people's thought.Change rules based on the spatio-temporal topological relations of evolution cadastral spatio-temporal objects are drafted and further more cascade updating and history back trace of cadastral features,land use and buildings are realized.This model implemented in cadastral management system-ReGIS.Achieved cascade changes are triggered by the direct driving force or perceived external events.The system records spatio-temporal objects' evolution process to facilitate the reconstruction of history,change tracking,analysis and forecasting future changes.

Phenotypic characterization of aberrant stem and progenitor cell populations in myelodysplastic syndromes.

Science.gov (United States)

Ostendorf, Benjamin N; Flenner, Eva; Flörcken, Anne; Westermann, Jörg

2018-01-01

Recent reports have revealed myelodysplastic syndromes (MDS) to arise from cancer stem cells phenotypically similar to physiological hematopoietic stem cells. Myelodysplastic hematopoiesis maintains a hierarchical organization, but the proportion of several hematopoietic compartments is skewed and multiple surface markers are aberrantly expressed. These aberrant antigen expression patterns hold diagnostic and therapeutic promise. However, eradication of MDS requires targeting of early myelodysplasia propagating stem cells. This warrants an exact assessment of the differentiation stage at which aberrant expression occurs in transformed hematopoiesis. Here, we report results on the prospective and extensive dissection of the hematopoietic hierarchy in 20 patients with either low-risk MDS or MDS with excess blasts and compare it to hematopoiesis in patients with non-malignancy-associated cytopenia or B cell lymphoma without bone marrow infiltration. We found patients with MDS with excess blasts to exhibit characteristic expansions of specific immature progenitor compartments. We also identified the aberrant expression of several markers including ALDH, CLL-1, CD44, and CD47 to be specific features of hematopoiesis in MDS with excess blasts. We show that amongst these, aberrant CLL-1 expression manifested at the early uncommitted hematopoietic stem cell level, suggesting a potential role as a therapeutic target.

Phenotypic characterization of aberrant stem and progenitor cell populations in myelodysplastic syndromes.

Directory of Open Access Journals (Sweden)

Benjamin N Ostendorf

Full Text Available Recent reports have revealed myelodysplastic syndromes (MDS to arise from cancer stem cells phenotypically similar to physiological hematopoietic stem cells. Myelodysplastic hematopoiesis maintains a hierarchical organization, but the proportion of several hematopoietic compartments is skewed and multiple surface markers are aberrantly expressed. These aberrant antigen expression patterns hold diagnostic and therapeutic promise. However, eradication of MDS requires targeting of early myelodysplasia propagating stem cells. This warrants an exact assessment of the differentiation stage at which aberrant expression occurs in transformed hematopoiesis. Here, we report results on the prospective and extensive dissection of the hematopoietic hierarchy in 20 patients with either low-risk MDS or MDS with excess blasts and compare it to hematopoiesis in patients with non-malignancy-associated cytopenia or B cell lymphoma without bone marrow infiltration. We found patients with MDS with excess blasts to exhibit characteristic expansions of specific immature progenitor compartments. We also identified the aberrant expression of several markers including ALDH, CLL-1, CD44, and CD47 to be specific features of hematopoiesis in MDS with excess blasts. We show that amongst these, aberrant CLL-1 expression manifested at the early uncommitted hematopoietic stem cell level, suggesting a potential role as a therapeutic target.

What Is Spatio-Temporal Data Warehousing?

Science.gov (United States)

Vaisman, Alejandro; Zimányi, Esteban

In the last years, extending OLAP (On-Line Analytical Processing) systems with spatial and temporal features has attracted the attention of the GIS (Geographic Information Systems) and database communities. However, there is no a commonly agreed definition of what is a spatio-temporal data warehouse and what functionality such a data warehouse should support. Further, the solutions proposed in the literature vary considerably in the kind of data that can be represented as well as the kind of queries that can be expressed. In this paper we present a conceptual framework for defining spatio-temporal data warehouses using an extensible data type system. We also define a taxonomy of different classes of queries of increasing expressive power, and show how to express such queries using an extension of the tuple relational calculus with aggregated functions.

Aberrant functional connectivity between motor and language networks in rolandic epilepsy.

Science.gov (United States)

Besseling, René M H; Overvliet, Geke M; Jansen, Jacobus F A; van der Kruijs, Sylvie J M; Vles, Johannes S H; Ebus, Saskia C M; Hofman, Paul A M; de Louw, Anton J A; Aldenkamp, Albert P; Backes, Walter H

2013-12-01

Rolandic epilepsy (RE) is an idiopathic focal childhood epilepsy with a well-established neuropsychological profile of language impairment. The aim of this study is to provide a functional correlate that links rolandic (sensorimotor) pathology to language problems using functional MRI. Twenty-three children with RE (8-14 years old) and 21 matched controls underwent extensive language assessment (Clinical Evaluation of Language Fundamentals). fMRI was performed at rest and using word generation, reading, and finger tapping paradigms. Since no activation group differences were found, regions of interest (ROIs) were defined at pooled (patients and controls combined) activation maxima and in contralateral homotopic cortex, and used to assess language lateralization as well as for a resting-state connectivity analysis. Furthermore, the association between connection strength and language performance was investigated. Reduced language performance was found in the children with RE. Bilateral activation was found for both language tasks with some predominance of the left hemisphere in both groups. Compared to controls, patient connectivity was decreased between the left sensorimotor area and right inferior frontal gyrus (planguage scores in the patient group (r=0.49, p=0.02), but not in the controls. Language laterality analysis revealed bilateral language representation in the age range under study (8-14 years). As a consequence, the connection of reduced functional connectivity we found represents an impaired interplay between motor and language networks, and aberrant functional connectivity associated with poorer language performance. These findings provide a first neuronal correlate in terms of aberrant resting-state functional connectivity for language impairment in RE. Copyright © 2013 Elsevier B.V. All rights reserved.

IgA Nephropathy and Henoch-Schoenlein Purpura Nephritis: Aberrant Glycosylation of IgA1, Formation of IgA1-Containing Immune Complexes, and Activation of Mesangial Cells

DEFF Research Database (Denmark)

Novak, J.; Moldoveanu, Z.; Renfrow, M.B.

2007-01-01

IgA1 in the circulation and glomerular deposits of patients with IgA nephropathy (IgAN) is aberrantly glycosylated; the hinge-region O-linked glycans are galactose-deficient. The circulating IgA1 of patients with Henoch-Schoenlein purpura nephritis (HSPN) has a similar defect. This aberrancy...

Spatio-temporal modeling of nonlinear distributed parameter systems

CERN Document Server

Li, Han-Xiong

2011-01-01

The purpose of this volume is to provide a brief review of the previous work on model reduction and identifi cation of distributed parameter systems (DPS), and develop new spatio-temporal models and their relevant identifi cation approaches. In this book, a systematic overview and classifi cation on the modeling of DPS is presented fi rst, which includes model reduction, parameter estimation and system identifi cation. Next, a class of block-oriented nonlinear systems in traditional lumped parameter systems (LPS) is extended to DPS, which results in the spatio-temporal Wiener and Hammerstein s

Visualization of Spatio-Temporal Relations in Movement Event Using Multi-View

Science.gov (United States)

Zheng, K.; Gu, D.; Fang, F.; Wang, Y.; Liu, H.; Zhao, W.; Zhang, M.; Li, Q.

2017-09-01

Spatio-temporal relations among movement events extracted from temporally varying trajectory data can provide useful information about the evolution of individual or collective movers, as well as their interactions with their spatial and temporal contexts. However, the pure statistical tools commonly used by analysts pose many difficulties, due to the large number of attributes embedded in multi-scale and multi-semantic trajectory data. The need for models that operate at multiple scales to search for relations at different locations within time and space, as well as intuitively interpret what these relations mean, also presents challenges. Since analysts do not know where or when these relevant spatio-temporal relations might emerge, these models must compute statistical summaries of multiple attributes at different granularities. In this paper, we propose a multi-view approach to visualize the spatio-temporal relations among movement events. We describe a method for visualizing movement events and spatio-temporal relations that uses multiple displays. A visual interface is presented, and the user can interactively select or filter spatial and temporal extents to guide the knowledge discovery process. We also demonstrate how this approach can help analysts to derive and explain the spatio-temporal relations of movement events from taxi trajectory data.

VISUALIZATION OF SPATIO-TEMPORAL RELATIONS IN MOVEMENT EVENT USING MULTI-VIEW

Directory of Open Access Journals (Sweden)

K. Zheng

2017-09-01

Full Text Available Spatio-temporal relations among movement events extracted from temporally varying trajectory data can provide useful information about the evolution of individual or collective movers, as well as their interactions with their spatial and temporal contexts. However, the pure statistical tools commonly used by analysts pose many difficulties, due to the large number of attributes embedded in multi-scale and multi-semantic trajectory data. The need for models that operate at multiple scales to search for relations at different locations within time and space, as well as intuitively interpret what these relations mean, also presents challenges. Since analysts do not know where or when these relevant spatio-temporal relations might emerge, these models must compute statistical summaries of multiple attributes at different granularities. In this paper, we propose a multi-view approach to visualize the spatio-temporal relations among movement events. We describe a method for visualizing movement events and spatio-temporal relations that uses multiple displays. A visual interface is presented, and the user can interactively select or filter spatial and temporal extents to guide the knowledge discovery process. We also demonstrate how this approach can help analysts to derive and explain the spatio-temporal relations of movement events from taxi trajectory data.

Mining Spatiotemporal Patterns of the Elder's Daily Movement

Science.gov (United States)

Chen, C. R.; Chen, C. F.; Liu, M. E.; Tsai, S. J.; Son, N. T.; Kinh, L. V.

2016-06-01

With rapid developments in wearable device technology, a vast amount of spatiotemporal data, such as people's movement and physical activities, are generated. Information derived from the data reveals important knowledge that can contribute a long-term care and psychological assessment of the elders' living condition especially in long-term care institutions. This study aims to develop a method to investigate the spatial-temporal movement patterns of the elders with their outdoor trajectory information. To achieve the goal, GPS based location data of the elderly subjects from long-term care institutions are collected and analysed with geographic information system (GIS). A GIS statistical model is developed to mine the elderly subjects' spatiotemporal patterns with the location data and represent their daily movement pattern at particular time. The proposed method first finds the meaningful trajectory and extracts the frequent patterns from the time-stamp location data. Then, a density-based clustering method is used to identify the major moving range and the gather/stay hotspot in both spatial and temporal dimensions. The preliminary results indicate that the major moving area of the elderly people encompasses their dorm and has a short moving distance who often stay in the same site. Subjects' outdoor appearance are corresponded to their life routine. The results can be useful for understanding elders' social network construction, risky area identification and medical care monitoring.

On- and off-eye spherical aberration of soft contact lenses and consequent changes of effective lens power.

Science.gov (United States)

Dietze, Holger H; Cox, Michael J

2003-02-01

Soft contact lenses produce a significant level of spherical aberration affecting their power on-eye. A simple model assuming that a thin soft contact lens aligns to the cornea predicts that these effects are similar on-eye and off-eye. The wavefront aberration for 17 eyes and 33 soft contact lenses on-eye was measured with a Shack-Hartmann wavefront sensor. The Zernike coefficients describing the on-eye spherical aberration of the soft contact lens were compared with off-eye ray-tracing results. Paraxial and effective lens power changes were determined. The model predicts the on-eye spherical aberration of soft contact lenses closely. The resulting power change for a +/- 7.00 D spherical soft contact lens is +/- 0.5 D for a 6-mm pupil diameter and +/- 0.1 D for a 3-mm pupil diameter. Power change is negligible for soft contact lenses corrected for off-eye spherical aberration. For thin soft contact lenses, the level of spherical aberration and the consequent power change is similar on-eye and off-eye. Soft contact lenses corrected for spherical aberration in air will be expected to be aberration-free on-eye and produce only negligibly small power changes. For soft contact lenses without aberration correction, for higher levels of ametropia and large pupils, the soft contact lens power should be determined with trial lenses with their power and p value similar to the prescribed lens. The benefit of soft contact lenses corrected for spherical aberration depends on the level of ocular spherical aberration.

Spontaneous and X-ray induced chromosomal aberrations in selected connective tissue diseases

International Nuclear Information System (INIS)

Burkhardt, W.C.; Jackson, J.F.; Songcharoen, S.; Meydrech, E.F.

1980-01-01

Chromosome studies were performed on peripheral blood lymphocytes of 28 patients with connective tissue disease (6 with progressive systemic sclerosis, 6 with systemic lupus erythematosus, 6 with anti-nuclear antibody positive rheumatoid arthritis, 6 with anti-nuclear antibody negative rheumatoid arthritis, and 4 with mixed connective tissue disease) and on 17 controls to determine the frequency of spontaneous as well as X-ray (75 rads) induced aberrations. The mean spontaneous chromosomal aberration frequency for the 28 patients (9.1%) was significantly (P=0.038) greater than that of controls (6.4%). When patients were categorized into specific clinically designated connective tissue disease subdivisions for comparison with the controls, only X-irradiated cells from the progressive systemic sclerosis group displayed significantly elevated levels of total chromosomal aberrations over those of the control group. The X-irradiated lymphocytes from these patients had an average of 23.6% aberrations per patient, while those of the control group showed an average of 14.9% per patient (P<0.05). (author)

Marginal estimator for the aberrations of a space telescope by phase diversity

Science.gov (United States)

Blanc, Amandine; Mugnier, Laurent; Idier, Jérôme

2017-11-01

In this communication, we propose a novel method for estimating the aberrations of a space telescope from phase diversity data. The images recorded by such a telescope can be degraded by optical aberrations due to design, fabrication or misalignments. Phase diversity is a technique that allows the estimation of aberrations. The only estimator found in the relevant literature is based on a joint estimation of the aberrated phase and the observed object. We recall this approach and study the behavior of this joint estimator by means of simulations. We propose a novel marginal estimator of the sole phase. it is obtained by integrating the observed object out of the problem; indeed, this object is a nuisance parameter in our problem. This reduces drastically the number of unknown and provides better asymptotic properties. This estimator is implemented and its properties are validated by simulation. its performance is equal or even better than that of the joint estimator for the same computing cost.

Spontaneous and X-ray induced chromosomal aberrations in selected connective tissue diseases

Energy Technology Data Exchange (ETDEWEB)

Burkhardt, W C; Jackson, J F; Songcharoen, S; Meydrech, E F [Mississippi Univ., Jackson (USA). Medical Center

1980-01-01

Chromosome studies were performed on peripheral blood lymphocytes of 28 patients with connective tissue disease (6 with progressive systemic sclerosis, 6 with systemic lupus erythematosus, 6 with anti-nuclear antibody positive rheumatoid arthritis, 6 with anti-nuclear antibody negative rheumatoid arthritis, and 4 with mixed connective tissue disease) and on 17 controls to determine the frequency of spontaneous as well as X-ray (75 rads) induced aberrations. The mean spontaneous chromosomal aberration frequency for the 28 patients (9.1%) was significantly (P=0.038) greater than that of controls (6.4%). When patients were categorized into specific clinically designated connective tissue disease subdivisions for comparison with the controls, only X-irradiated cells from the progressive systemic sclerosis group displayed significantly elevated levels of total chromosomal aberrations over those of the control group. The X-irradiated lymphocytes from these patients had an average of 23.6% aberrations per patient, while those of the control group showed an average of 14.9% per patient (P<0.05).

Brief history of the Cambridge STEM aberration correction project and its progeny

Energy Technology Data Exchange (ETDEWEB)

Brown, L. Michael [Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Batson, Philip E. [Institute for Advanced Materials, Devices and Nanotechnology, Rutgers University, Piscataway, NJ 08854 (United States); Department of Physics, Rutgers University, Piscataway, NJ 08854 (United States); Department of Materials Science, Rutgers University, Piscataway, NJ 08854 (United States); Dellby, Niklas [Nion Company, 11515 NE 118th Street, Kirkland, WA 98034 (United States); Krivanek, Ondrej L. [Nion Company, 11515 NE 118th Street, Kirkland, WA 98034 (United States); Department of Physics, Arizona State University, Tempe, AZ 85287 (United States)

2015-10-15

We provide a brief history of the project to correct the spherical aberration of the scanning transmission electron microscope (STEM) that started in Cambridge (UK) and continued in Kirkland (WA, USA), Yorktown Heights (NY, USA), and other places. We describe the project in the full context of other aberration correction research and related work, partly in response to the incomplete context presented in the paper “In quest of perfection in electron optics: A biographical sketch of Harald Rose on the occasion of his 80th birthday”, recently published in Ultramicroscopy. - Highlights: • We provide a brief history of the Cambridge project to correct the spherical aberration of the scanning transmission electron microscope (STEM). • We describe the project in the full context of other aberration correction work and related research. • We summarize our corrector development work that followed the Cambridge project, and which was the first to reach higher spatial resolution than any non-corrected electron microscope.

Brief history of the Cambridge STEM aberration correction project and its progeny

International Nuclear Information System (INIS)

Brown, L. Michael; Batson, Philip E.; Dellby, Niklas; Krivanek, Ondrej L.

2015-01-01

We provide a brief history of the project to correct the spherical aberration of the scanning transmission electron microscope (STEM) that started in Cambridge (UK) and continued in Kirkland (WA, USA), Yorktown Heights (NY, USA), and other places. We describe the project in the full context of other aberration correction research and related work, partly in response to the incomplete context presented in the paper “In quest of perfection in electron optics: A biographical sketch of Harald Rose on the occasion of his 80th birthday”, recently published in Ultramicroscopy. - Highlights: • We provide a brief history of the Cambridge project to correct the spherical aberration of the scanning transmission electron microscope (STEM). • We describe the project in the full context of other aberration correction work and related research. • We summarize our corrector development work that followed the Cambridge project, and which was the first to reach higher spatial resolution than any non-corrected electron microscope

Spatiotemporal network motif reveals the biological traits of developmental gene regulatory networks in Drosophila melanogaster

Directory of Open Access Journals (Sweden)

Kim Man-Sun

2012-05-01

Full Text Available Abstract Background Network motifs provided a “conceptual tool” for understanding the functional principles of biological networks, but such motifs have primarily been used to consider static network structures. Static networks, however, cannot be used to reveal time- and region-specific traits of biological systems. To overcome this limitation, we proposed the concept of a “spatiotemporal network motif,” a spatiotemporal sequence of network motifs of sub-networks which are active only at specific time points and body parts. Results On the basis of this concept, we analyzed the developmental gene regulatory network of the Drosophila melanogaster embryo. We identified spatiotemporal network motifs and investigated their distribution pattern in time and space. As a result, we found how key developmental processes are temporally and spatially regulated by the gene network. In particular, we found that nested feedback loops appeared frequently throughout the entire developmental process. From mathematical simulations, we found that mutual inhibition in the nested feedback loops contributes to the formation of spatial expression patterns. Conclusions Taken together, the proposed concept and the simulations can be used to unravel the design principle of developmental gene regulatory networks.

Analysis of Chromosomal Aberrations after Low and High Dose Rate Gamma Irradiation in ATM or NBS Suppressed Human Fibroblast Cells

Science.gov (United States)

Hada, M.; Huff, J. L.; Patel, Z.; Pluth, J. M.; George, K. A.; Cucinotta, F. A.

2009-01-01

A detailed understanding of the biological effects of heavy nuclei is needed for space radiation protection and for cancer therapy. High-LET radiation produces more complex DNA lesions that may be non-repairable or that may require additional processing steps compared to endogenous DSBs, increasing the possibility of misrepair. Interplay between radiation sensitivity, dose, and radiation quality has not been studied extensively. Previously we studied chromosome aberrations induced by low- and high- LET radiation in several cell lines deficient in ATM (ataxia telangactasia mutated; product of the gene that is mutated in ataxia telangiectasia patients) or NBS (nibrin; product of the gene mutated in the Nijmegen breakage syndrome), and gliomablastoma cells that are proficient or lacking in DNA-dependent protein kinase (DNA-PK) activity. We found that the yields of both simple and complex chromosomal aberrations were significantly increased in the DSB repair defective cells compared to normal cells. The increased aberrations observed for the ATM and NBS defective lines was due to a significantly larger quadratic dose-response term compared to normal fibroblasts for both simple and complex aberrations, while the linear dose-response term was significantly higher in NBS cells only for simple exchanges. These results point to the importance of the functions of ATM and NBS in chromatin modifications that function to facilitate correct DSB repair and minimize aberration formation. To further understand the sensitivity differences that were observed in ATM and NBS deficient cells, in this study, chromosomal aberration analysis was performed in normal lung fibroblast cells treated with KU-55933, a specific ATM kinase inhibitor, or Mirin, an MRN complex inhibitor involved in activation of ATM. We are also testing siRNA knockdown of these proteins. Normal and ATM or NBS suppressed cells were irradiated with gamma-rays and chromosomes were collected with a premature chromosome

Numerical correction of anti-symmetric aberrations in single HRTEM images of weakly scattering 2D-objects

International Nuclear Information System (INIS)

Lehtinen, Ossi; Geiger, Dorin; Lee, Zhongbo; Whitwick, Michael Brian; Chen, Ming-Wei; Kis, Andras; Kaiser, Ute

2015-01-01

Here, we present a numerical post-processing method for removing the effect of anti-symmetric residual aberrations in high-resolution transmission electron microscopy (HRTEM) images of weakly scattering 2D-objects. The method is based on applying the same aberrations with the opposite phase to the Fourier transform of the recorded image intensity and subsequently inverting the Fourier transform. We present the theoretical justification of the method, and its verification based on simulated images in the case of low-order anti-symmetric aberrations. Ultimately the method is applied to experimental hardware aberration-corrected HRTEM images of single-layer graphene and MoSe 2 resulting in images with strongly reduced residual low-order aberrations, and consequently improved interpretability. Alternatively, this method can be used to estimate by trial and error the residual anti-symmetric aberrations in HRTEM images of weakly scattering objects

The effect of aberrated recording beams on reflecting Bragg gratings

Science.gov (United States)

SeGall, Marc; Ott, Daniel; Divliansky, Ivan; Glebov, Leonid B.

2013-03-01

The effect of aberrations present in the recording beams of a holographic setup is discussed regarding the period and spectral response of a reflecting volume Bragg grating. Imperfect recording beams result in spatially varying resonant wavelengths and the side lobes of the spectrum are washed out. Asymmetrical spectra, spectral broadening, and a reduction in peak diffraction efficiency may also be present, though these effects are less significant for gratings with wider spectral widths. Reflecting Bragg gratings (RBGs) are used as elements in a variety of applications including spectral beam combining1,2, mode locking3,4, longitudinal and transverse mode selection in lasers5,6, and sensing7,8. For applications requiring narrow spectral selectivity9, or large apertures10, these gratings must have a uniform period throughout the length of the recording medium, which may be on the order of millimeters. However, when using typical recording techniques such as two-beam interference for large aperture gratings and phase-mask recording of fiber gratings, aberrations from the optical elements in the system result in an imperfect grating structure11-13. In this paper we consider the effects of aberrations on large aperture gratings recorded in thick media using the two-beam interference technique. Previous works in analyzing the effects of aberrations have considered the effects of aberrations in a single recording plane where the beams perfectly overlap. Such an approach is valid for thin media (on the order of tens of microns), but for thick recording media (on the order of several millimeters) there will be a significant shift in the positions of the beams relative to each other as they traverse the recording medium. Therefore, the fringe pattern produced will not be constant throughout the grating if one or both beams have a non-uniform wavefront. Such non-uniform gratings may have a wider spectral width, a shifted resonant wavelength, or other problems. It is

Research development of thermal aberration in 193nm lithography exposure system

Science.gov (United States)

Wang, Yueqiang; Liu, Yong

2014-08-01

Lithographic exposure is the key process in the manufacture of the integrated circuit, and the performance of exposure system decides the level of microelectronic manufacture technology. Nowadays, the 193nm ArF immersion exposure tool is widely used by the IC manufacturer. With the uniformity of critical dimension (CDU) and overlay become tighter and the requirement for throughput become higher, the thermal aberration caused by lens material and structure absorbing the laser energy cannot be neglected. In this paper, we introduce the efforts and methods that researcher on thermal aberration and its control. Further, these methods were compared to show their own pros and cons. Finally we investigated the challenges of thermal aberration control for state of the art technologies.

Aberrant overian artery originating from the Ilolumbar artery: A case report

Energy Technology Data Exchange (ETDEWEB)

Lee, Ji Eun; Lee, Jae Myeong [Dept. of Radiology, Soonchunhyang University College of Medicine, Bucheon Hospital, Bucheon (Korea, Republic of)

2016-05-15

Here, we report a case of a 30-year-old woman who presented with primary postpartum hemorrhage due to uterine atony. She received uterine artery embolization (UAE). During left internal iliac arteriography, an aberrant left ovarian artery originating from the left iliolumbar artery was visualized. The aberrant left ovarian artery was connected to the left uterine artery via prominent collateral vessels. It supplied a significant amount of blood to the fundus of the uterus. Bilateral hypertrophied uterine arteries were embolized very carefully so that the embolic material did not reflux into the aberrant left ovarian artery. After the procedure, her vaginal bleeding was successfully controlled. Accurate understanding of anatomical variations of the ovarian artery is essential to avoid failure in controlling postpartum hemorrhage with UAE.

Aberrant overian artery originating from the Ilolumbar artery: A case report

International Nuclear Information System (INIS)

Lee, Ji Eun; Lee, Jae Myeong

2016-01-01

Here, we report a case of a 30-year-old woman who presented with primary postpartum hemorrhage due to uterine atony. She received uterine artery embolization (UAE). During left internal iliac arteriography, an aberrant left ovarian artery originating from the left iliolumbar artery was visualized. The aberrant left ovarian artery was connected to the left uterine artery via prominent collateral vessels. It supplied a significant amount of blood to the fundus of the uterus. Bilateral hypertrophied uterine arteries were embolized very carefully so that the embolic material did not reflux into the aberrant left ovarian artery. After the procedure, her vaginal bleeding was successfully controlled. Accurate understanding of anatomical variations of the ovarian artery is essential to avoid failure in controlling postpartum hemorrhage with UAE

Resection-Reconstruction of Aberrant Right Hepatic Artery During Whipple Procedure (Pancreaticoduodenectomy).

Science.gov (United States)

Sayyed, Raza; Rehman, Iffat; Niazi, Imran Khalid; Yusuf, Muhammed Aasim; Syed, Aamir Ali; V, Faisal

2016-06-01

Aberrant hepatic arterial anatomy poses a challenge for the surgeon during Whipple procedure. Intraoperative injury to the aberrant vasculature results in hemorrhagic or ischemic complications involving the liver and biliary tree. We report a case of replaced right hepatic artery arising from the superior mesenteric artery in a patient with periampullary carcinoma of the pancreas, undergoing pancreaticoduodenectomy. The aberrant artery was found to be coursing through the pancreatic parenchyma. This is a rare vascular anomaly. Resection of the arterial segment and end-to-end anastomosis was fashioned. Intrapancreatic course of the replaced right hepatic artery is a rare anomaly and is best managed by preoperative identification on radiology and meticulous intra-operative dissection and preservation. However, for an intrapancreatic course, resection and reconstruction may occasionally be required.

Chromosomal Aberrations in Humans Induced by Urban Air Pollution

DEFF Research Database (Denmark)

Knudsen, Lisbeth E.; Norppa, Hannu; Gamborg, Michael O.

1999-01-01

We have studied the influence of individual susceptibility factors on the genotoxic effects of urban air pollution in 106 nonsmoking bus drivers and 101 postal workers in the Copenhagen metropolitan area. We used the frequency of chromosomal aberrations in peripheral blood lymphocytes as a biomar......We have studied the influence of individual susceptibility factors on the genotoxic effects of urban air pollution in 106 nonsmoking bus drivers and 101 postal workers in the Copenhagen metropolitan area. We used the frequency of chromosomal aberrations in peripheral blood lymphocytes...... that long-term exposure to urban air pollution (with traffic as the main contributor) induces chromosome damage in human somatic cells. Low DNA repair capacity and GSTM1 and NAT2 variants associated with reduced detoxification ability increase susceptibility to such damage. The effect of the GSTM1 genotype......, which was observed only in the bus drivers, appears to be associated with air pollution, whereas the NAT2 genotype effect, which affected all subjects, may influence the individual response to some other common exposure or the baseline level of chromosomal aberrations....

Origin of specific chromosome aberration in radiation-induced leukemia

International Nuclear Information System (INIS)

Ban, Nobuhiko; Kai, Michiaki; Masuno, Yoko

2005-01-01

The theme in the title is discussed from the four aspects of specific chromosome aberration (sAb) patterns in radiation-induced leukemia (RIL), possibility for radiation to induce the sAb in RIL, any evidence for participation of delayed aberration to form sAb and the proportion of such healthy humans as having the specifically rearranged genome. Data of sAb observed in leukemia of 25 A-bomb survivors and of 38 patients post radiotherapy of cancers give a rather common pattern. However, many inconsistent results are obtained for sAb in patients post radiotherapy, A-bomb survivors, residents living in radio-contaminated houses in Taipei, in vitro exposure, and Chernobyl residents. At present, any clear evidence is available neither for sAb derived from the delayed aberration nor for estimating the proportion with the specifically rearranged gene. As above, it is unlikely that radiation induces such a translocation abnormality as BCR-ABL specifically seen in leukemia, and this aspect will be important for studies on the genesis of RIL and its risk assessment. (S.I.)

Bayesian spatio-temporal modeling of particulate matter concentrations in Peninsular Malaysia

Science.gov (United States)

Manga, Edna; Awang, Norhashidah

2016-06-01

This article presents an application of a Bayesian spatio-temporal Gaussian process (GP) model on particulate matter concentrations from Peninsular Malaysia. We analyze daily PM10 concentration levels from 35 monitoring sites in June and July 2011. The spatiotemporal model set in a Bayesian hierarchical framework allows for inclusion of informative covariates, meteorological variables and spatiotemporal interactions. Posterior density estimates of the model parameters are obtained by Markov chain Monte Carlo methods. Preliminary data analysis indicate information on PM10 levels at sites classified as industrial locations could explain part of the space time variations. We include the site-type indicator in our modeling efforts. Results of the parameter estimates for the fitted GP model show significant spatio-temporal structure and positive effect of the location-type explanatory variable. We also compute some validation criteria for the out of sample sites that show the adequacy of the model for predicting PM10 at unmonitored sites.

Electrophysiological evidence for spatiotemporal flexibility in the ventrolateral attention network.

Directory of Open Access Journals (Sweden)

Jelena Ristic

Full Text Available Successful completion of many everyday tasks depends on interactions between voluntary attention, which acts to maintain current goals, and reflexive attention, which enables responding to unexpected events by interrupting the current focus of attention. Past studies, which have mostly examined each attentional mechanism in isolation, indicate that volitional and reflexive orienting depend on two functionally specialized cortical networks in the human brain. Here we investigated how the interplay between these two cortical networks affects sensory processing and the resulting overt behavior. By combining measurements of human performance and electrocortical recordings with a novel analytical technique for estimating spatiotemporal activity in the human cortex, we found that the subregions that comprise the reflexive ventrolateral attention network dissociate both spatially and temporally as a function of the nature of the sensory information and current task demands. Moreover, we found that together with the magnitude of the early sensory gain, the spatiotemporal neural dynamics accounted for the high amount of the variance in the behavioral data. Collectively these data support the conclusion that the ventrolateral attention network is recruited flexibly to support complex behaviors.

Quality factor of aberrated gaussian laser beams

CSIR Research Space (South Africa)

Mafusire, C

2010-09-01

Full Text Available 15 20 25 30 35 M 4 © CSIR 2010 www.csir.co.za Conclusion • Laser beam quality depends on - y-Astigmatism - y-Coma - x-Coma - y-Triangular astigmatism - x-Triangular astigmatism - Spherical aberration...

Aberrations in preliminary design of ITER divertor impurity influx monitor

Energy Technology Data Exchange (ETDEWEB)

Kitazawa, Sin-iti, E-mail: kitazawa.siniti@jaea.go.jp [Naka Fusion Institute, Japan Atomic Energy Agency, JAEA, Naka 311-0193 (Japan); Ogawa, Hiroaki [Naka Fusion Institute, Japan Atomic Energy Agency, JAEA, Naka 311-0193 (Japan); Katsunuma, Atsushi; Kitazawa, Daisuke [Core Technology Center, Nikon Corporation, Yokohama 244-8533 (Japan); Ohmori, Keisuke [Customized Products Business Unit, Nikon Corporation, Mito 310-0843 (Japan)

2015-12-15

Highlights: • Divertor impurity influx monitor for ITER (DIM) is procured by JADA. • DIM is designed to observe light from nuclear fusion plasma directly. • DIM is under preliminary design phase. • The spot diagrams were suppressed within the core of receiving fiber. • The aberration of DIM is suppressed in the preliminary design. - Abstract: Divertor impurity influx monitor for ITER (DIM) is a diagnostic system that observes light from nuclear fusion plasma directly. This system is affected by various aberrations because it observes light from the fan-array chord near the divertor in the ultraviolet–near infrared wavelength range. The aberrations should be suppressed to the extent possible to observe the light with very high spatial resolution. In the preliminary design of DIM, spot diagrams were suppressed within the core of the receiving fiber's cross section, and the resulting spatial resolutions satisfied the design requirements.

Aberrations in preliminary design of ITER divertor impurity influx monitor

International Nuclear Information System (INIS)

Kitazawa, Sin-iti; Ogawa, Hiroaki; Katsunuma, Atsushi; Kitazawa, Daisuke; Ohmori, Keisuke

2015-01-01

Highlights: • Divertor impurity influx monitor for ITER (DIM) is procured by JADA. • DIM is designed to observe light from nuclear fusion plasma directly. • DIM is under preliminary design phase. • The spot diagrams were suppressed within the core of receiving fiber. • The aberration of DIM is suppressed in the preliminary design. - Abstract: Divertor impurity influx monitor for ITER (DIM) is a diagnostic system that observes light from nuclear fusion plasma directly. This system is affected by various aberrations because it observes light from the fan-array chord near the divertor in the ultraviolet–near infrared wavelength range. The aberrations should be suppressed to the extent possible to observe the light with very high spatial resolution. In the preliminary design of DIM, spot diagrams were suppressed within the core of the receiving fiber's cross section, and the resulting spatial resolutions satisfied the design requirements.

Wave fronts and spatiotemporal chaos in an array of coupled Lorenz oscillators

International Nuclear Information System (INIS)

Pazo, Diego; Montejo, Noelia; Perez-Munuzuri, Vicente

2001-01-01

The effects of coupling strength and single-cell dynamics (SCD) on spatiotemporal pattern formation are studied in an array of Lorenz oscillators. Different spatiotemporal structures (stationary patterns, propagating wave fronts, short wavelength bifurcation) arise for bistable SCD, and two well differentiated types of spatiotemporal chaos for chaotic SCD (in correspondence with the transition from stationary patterns to propagating fronts). Wave-front propagation in the bistable regime is studied in terms of global bifurcation theory, while a short wavelength pattern region emerges through a pitchfork bifurcation

Optimum aberration coefficients for recording high-resolution off-axis holograms in a Cs-corrected TEM

Energy Technology Data Exchange (ETDEWEB)

Linck, Martin, E-mail: linck@ceos-gmbh.de [CEOS GmbH, Englerstr. 28, D-69126 Heidelberg (Germany)

2013-01-15

Amongst the impressive improvements in high-resolution electron microscopy, the Cs-corrector also has significantly enhanced the capabilities of off-axis electron holography. Recently, it has been shown that the signal above noise in the reconstructable phase can be significantly improved by combining holography and hardware aberration correction. Additionally, with a spherical aberration close to zero, the traditional optimum focus for recording high-resolution holograms ('Lichte's defocus') has become less stringent and both, defocus and spherical aberration, can be selected freely within a certain range. This new degree of freedom can be used to improve the signal resolution in the holographically reconstructed object wave locally, e.g. at the atomic positions. A brute force simulation study for an aberration corrected 200 kV TEM is performed to determine optimum values for defocus and spherical aberration for best possible signal to noise in the reconstructed atomic phase signals. Compared to the optimum aberrations for conventional phase contrast imaging (NCSI), which produce 'bright atoms' in the image intensity, the resulting optimum values of defocus and spherical aberration for off-axis holography enable 'black atom contrast' in the hologram. However, they can significantly enhance the local signal resolution at the atomic positions. At the same time, the benefits of hardware aberration correction for high-resolution off-axis holography are preserved. It turns out that the optimum is depending on the object and its thickness and therefore not universal. -- Highlights: Black-Right-Pointing-Pointer Optimized aberration parameters for high-resolution off-axis holography. Black-Right-Pointing-Pointer Simulation and analysis of noise in high-resolution off-axis holograms. Black-Right-Pointing-Pointer Improving signal resolution in the holographically reconstructed phase shift. Black-Right-Pointing-Pointer Comparison of &apos

Optimum aberration coefficients for recording high-resolution off-axis holograms in a Cs-corrected TEM

International Nuclear Information System (INIS)

Linck, Martin

2013-01-01

Amongst the impressive improvements in high-resolution electron microscopy, the Cs-corrector also has significantly enhanced the capabilities of off-axis electron holography. Recently, it has been shown that the signal above noise in the reconstructable phase can be significantly improved by combining holography and hardware aberration correction. Additionally, with a spherical aberration close to zero, the traditional optimum focus for recording high-resolution holograms (“Lichte's defocus”) has become less stringent and both, defocus and spherical aberration, can be selected freely within a certain range. This new degree of freedom can be used to improve the signal resolution in the holographically reconstructed object wave locally, e.g. at the atomic positions. A brute force simulation study for an aberration corrected 200 kV TEM is performed to determine optimum values for defocus and spherical aberration for best possible signal to noise in the reconstructed atomic phase signals. Compared to the optimum aberrations for conventional phase contrast imaging (NCSI), which produce “bright atoms” in the image intensity, the resulting optimum values of defocus and spherical aberration for off-axis holography enable “black atom contrast” in the hologram. However, they can significantly enhance the local signal resolution at the atomic positions. At the same time, the benefits of hardware aberration correction for high-resolution off-axis holography are preserved. It turns out that the optimum is depending on the object and its thickness and therefore not universal. -- Highlights: ► Optimized aberration parameters for high-resolution off-axis holography. ► Simulation and analysis of noise in high-resolution off-axis holograms. ► Improving signal resolution in the holographically reconstructed phase shift. ► Comparison of “black” and “white” atom contrast in off-axis holograms.

A flexible spatiotemporal method for fusing satellite images with different resolutions

Science.gov (United States)

Xiaolin Zhu; Eileen H. Helmer; Feng Gao; Desheng Liu; Jin Chen; Michael A. Lefsky

2016-01-01

Studies of land surface dynamics in heterogeneous landscapes often require remote sensing datawith high acquisition frequency and high spatial resolution. However, no single sensor meets this requirement. This study presents a new spatiotemporal data fusion method, the Flexible Spatiotemporal DAta Fusion (FSDAF) method, to generate synthesized frequent high spatial...

Carrier and aberrations removal in interferometric fringe projection profilometry

Science.gov (United States)

Blain, P.; Michel, F.; Renotte, Y.; Habraken, S.

2012-04-01

A profilometer which takes advantage of polarization states splitting technique and monochromatic light projection method as a way to overcome ambient lighting for in-situ measurement is under development [1, 2]. Because of the Savart plate which refracts two out of axis beams, the device suffers from aberrations (mostly coma and astigmatism). These aberrations affect the quality of the sinusoidal fringe pattern. In fringe projection profilometry, the unwrapped phase distribution map contains the sum of the object's shape-related phase and carrier-fringe-related phase. In order to extract the 3D shape of the object, the carrier phase has to be removed [3, 4]. An easy way to remove both the fringe carrier and the aberrations of the optical system is to measure the phases of the test object and to measure the phase of a reference plane with the same set up and to subtract both phase maps. This time consuming technique is suitable for laboratory but not for industry. We propose a method to numerically remove both the fringe carrier and the aberrations. A first reference phase of a calibration plane is evaluated knowing the position of the different elements in the set up and the orientation of the fringes. Then a fitting of the phase map by Zernike polynomials is computed [5]. As the triangulation parameters are known during the calibration, the computation of Zernike coefficients has only to be made once. The wavefront error can be adjusted by a scale factor which depends on the position of the test object.

Research on the Phase Aberration Correction with a Deformable Mirror Controlled by a Genetic Algorithm

International Nuclear Information System (INIS)

Yang, P; Hu, S J; Chen, S Q; Yang, W; Xu, B; Jiang, W H

2006-01-01

In order to improve laser beam quality, a real number encoding genetic algorithm based on adaptive optics technology was presented. This algorithm was applied to control a 19-channel deformable mirror to correct phase aberration in laser beam. It is known that when traditional adaptive optics system is used to correct laser beam wave-front phase aberration, a precondition is to measure the phase aberration information in the laser beam. However, using genetic algorithms, there is no necessary to know the phase aberration information in the laser beam beforehand. The only parameter need to know is the Light intensity behind the pinhole on the focal plane. This parameter was used as the fitness function for the genetic algorithm. Simulation results show that the optimal shape of the 19-channel deformable mirror applied to correct the phase aberration can be ascertained. The peak light intensity was improved by a factor of 21, and the encircled energy strehl ratio was increased to 0.34 from 0.02 as the phase aberration was corrected with this technique

Hyperthermic radiosensitization of synchronous Chinese hamster cells: relationship between lethality and chromosomal aberrations

International Nuclear Information System (INIS)

Dewey, W.C.; Sapareto, S.A.; Betten, D.A.

1978-01-01

Synchronous Chinese hamster cells in vitro were obtained by mitotic selection. The cells were heated at 45.5 0 C for 4 min in mitosis, 11 min in G 1 , or 7 min in S sphase and then x-irradiated immediately thereafter. Colony survival from heat alone was 0.30 to 0.45, and the frequency of chromosomal aberrations induced by heat was 0.00, 0.14, or 0.97 for heat treatments during M, G 1 , or S, respectively. As shown previously, lethality from hyperthermia alone is due to chromosomal aberrations only when the cells are heated during S phase. The log survival (D 0 /sup approximately/ = 80 rad) and aberration frequency curves for cells irradiated during mitosis were linear, and the only effect of hyperthermia was to shift the curves in accord with the effect from heat alone. Thus, hyperthermia did not radiosensitize the mitotic cells. The cells irradiated in G 1 were more resistant (D 0 /sup approximately/ = 100 rad) than those irradiated in mitosis, and the survival and aberration frequency curves both had shoulders. The primary effect of hyperthermia was to greatly reduce the shoulders of the curves and to increase the slopes by about 23%. The cells irradiated in S were the most resistant (D 0 /sup approximately/ = 140 rad), and the survival and aberration frequency curves both had large shoulders. For both end points of lethality and chromosomal aberrations, heat selectively radiosensitized S-phase cells relative to G 1 cells by removing most of the shoulder and increasing the slope by about 45%. For cells treated in G 1 or S, the increase in radiosensitization following hyperthermia can be accounted for by an increase in the frequency of chromosomal aberrations

Aberrant membranous expression of β-catenin predicts poor prognosis in patients with craniopharyngioma.

Science.gov (United States)

Li, Zongping; Xu, Jianguo; Huang, Siqing; You, Chao

2015-12-01

The objective of this study is to investigate β-catenin expression in craniopharyngioma patients and determine its significance in predicting the prognosis of this disease. Fifty craniopharyngioma patients were enrolled in this study. Expression of β-catenin in tumor specimens collected from these patients was examined through immunostaining. In addition, mutation of exon 3 in the β-catenin gene, CTNNB1, was analyzed using polymerase chain reaction, denaturing high-pressure liquid chromatography, and DNA sequencing. Based on these results, we explored the association between membranous β-catenin expression, clinical and pathologic characteristics, and prognoses in these patients. Of all craniopharyngioma specimens, 31 (62.0%) had preserved membranous β-catenin expression, whereas the remaining 19 specimens (38.0%) displayed aberrant expression. Statistical analysis showed a significant correlation between aberrant membranous β-catenin expression and CTNNB1 exon 3 mutation, as well as between aberrant membranous β-catenin expression and the histopathologic type of craniopharyngioma and type of resection in our patient population. Furthermore, aberrant membranous β-catenin expression was found to be associated with poor patient survival. Results of Kaplan-Meier survival analysis and Cox regression analysis further confirmed this finding. In conclusion, our study demonstrated that aberrant membranous β-catenin expression was significantly correlated with poor survival in patients with craniopharyngioma. This raises the possibility for use of aberrant membranous β-catenin expression as an independent risk factor in predicting the prognosis of this disease. Copyright © 2015 Elsevier Inc. All rights reserved.

Harbour porpoise distribution can vary at small spatiotemporal scales in energetic habitats

Science.gov (United States)

Benjamins, Steven; van Geel, Nienke; Hastie, Gordon; Elliott, Jim; Wilson, Ben

2017-07-01

Marine habitat heterogeneity underpins species distribution and can be generated through interactions between physical and biological drivers at multiple spatiotemporal scales. Passive acoustic monitoring (PAM) is used worldwide to study potential impacts of marine industrial activities on cetaceans, but understanding of animals' site use at small spatiotemporal scales (marine renewable energy development (MRED) sites was investigated by deploying dense arrays of C-POD passive acoustic detectors at a wave energy test site (the European Marine Energy Centre [Billia Croo, Orkney]) and by a minor tidal-stream site (Scarba [Inner Hebrides]). Respective arrays consisted of 7 and 11 moorings containing two C-PODs each and were deployed for up to 55 days. Minimum inter-mooring distances varied between 300-600 m. All C-POD data were analysed at a temporal resolution of whole minutes, with each minute classified as 1 or 0 on the basis of presence/absence of porpoise click trains (Porpoise-Positive Minutes/PPMs). Porpoise detection rates were analysed using Generalised Additive Models (GAMs) with Generalised Estimation Equations (GEEs). Although there were many porpoise detections (wave test site: N=3,432; tidal-stream site: N=17,366), daily detection rates varied significantly within both arrays. Within the wave site array (<1 km diameter), average daily detection rates varied from 4.3 to 14.8 PPMs/day. Within the tidal-stream array (<2 km diameter), average daily detection rates varied from 10.3 to 49.7 PPMs/day. GAM-GEE model results for individual moorings within both arrays indicated linkages between porpoise presence and small-scale heterogeneity among different environmental covariates (e.g., tidal phase, time of day). Porpoise detection rates varied considerably but with coherent patterns between moorings only several hundred metres apart and within hours. These patterns presumably have ecological relevance. These results indicate that, in energetically active and

Chromatic aberration correction: an enhancement to the calibration of low-cost digital dermoscopes.

Science.gov (United States)

Wighton, Paul; Lee, Tim K; Lui, Harvey; McLean, David; Atkins, M Stella

2011-08-01

We present a method for calibrating low-cost digital dermoscopes that corrects for color and inconsistent lighting and also corrects for chromatic aberration. Chromatic aberration is a form of radial distortion that often occurs in inexpensive digital dermoscopes and creates red and blue halo-like effects on edges. Being radial in nature, distortions due to chromatic aberration are not constant across the image, but rather vary in both magnitude and direction. As a result, distortions are not only visually distracting but could also mislead automated characterization techniques. Two low-cost dermoscopes, based on different consumer-grade cameras, were tested. Color is corrected by imaging a reference and applying singular value decomposition to determine the transformation required to ensure accurate color reproduction. Lighting is corrected by imaging a uniform surface and creating lighting correction maps. Chromatic aberration is corrected using a second-order radial distortion model. Our results for color and lighting calibration are consistent with previously published results, while distortions due to chromatic aberration can be reduced by 42-47% in the two systems considered. The disadvantages of inexpensive dermoscopy can be quickly substantially mitigated with a suitable calibration procedure. © 2011 John Wiley & Sons A/S.

Six years of cytogenetic follow-up of unstable chromosome aberrations in Goiania patients

International Nuclear Information System (INIS)

Ramalho, A.T.; Curado, M.P.; Natarajan, A.T.; Cohen, J.A.

2000-01-01

Following the radiological accident which occurred in the city of Goiania (Brazil), in September of 1987, a cytogenetic follow-up of 16 exposed patients was started, aiming to observe the mean life time of lymphocytes containing dicentric and ring aberrations. The results suggest that for the highly exposed individuals (doses above 1 Gy) the disappearance rate of unstable aberrations follows a two-term exponential function. Up to 470 days after exposure, there is a rapid fall in the aberration frequency. After 470 days, the disappearance rate is very slow. These results may reflect different subpopulations of human lymphocytes, with different life spans. The estimated average half-time of elimination of dicentrics and rings among the highly exposed group (doses above 1 Gy) was 140 days for the initial period after the exposure (up to 470 days). This value is significantly shorter than the usually accepted value of 3 years reported in the literature. For the individuals who had received less than 1 Gy the disappearance of aberrations seems to have occurred in a slower way. Mean disappearance functions of unstable chromosome aberrations were inferred, to be applied in accident situations in which there is a blood sampling delay. (author)

ELASTIC CLOUD COMPUTING ARCHITECTURE AND SYSTEM FOR HETEROGENEOUS SPATIOTEMPORAL COMPUTING

Directory of Open Access Journals (Sweden)

X. Shi

2017-10-01

Full Text Available Spatiotemporal computation implements a variety of different algorithms. When big data are involved, desktop computer or standalone application may not be able to complete the computation task due to limited memory and computing power. Now that a variety of hardware accelerators and computing platforms are available to improve the performance of geocomputation, different algorithms may have different behavior on different computing infrastructure and platforms. Some are perfect for implementation on a cluster of graphics processing units (GPUs, while GPUs may not be useful on certain kind of spatiotemporal computation. This is the same situation in utilizing a cluster of Intel's many-integrated-core (MIC or Xeon Phi, as well as Hadoop or Spark platforms, to handle big spatiotemporal data. Furthermore, considering the energy efficiency requirement in general computation, Field Programmable Gate Array (FPGA may be a better solution for better energy efficiency when the performance of computation could be similar or better than GPUs and MICs. It is expected that an elastic cloud computing architecture and system that integrates all of GPUs, MICs, and FPGAs could be developed and deployed to support spatiotemporal computing over heterogeneous data types and computational problems.

Elastic Cloud Computing Architecture and System for Heterogeneous Spatiotemporal Computing

Science.gov (United States)

Shi, X.

2017-10-01

Spatiotemporal computation implements a variety of different algorithms. When big data are involved, desktop computer or standalone application may not be able to complete the computation task due to limited memory and computing power. Now that a variety of hardware accelerators and computing platforms are available to improve the performance of geocomputation, different algorithms may have different behavior on different computing infrastructure and platforms. Some are perfect for implementation on a cluster of graphics processing units (GPUs), while GPUs may not be useful on certain kind of spatiotemporal computation. This is the same situation in utilizing a cluster of Intel's many-integrated-core (MIC) or Xeon Phi, as well as Hadoop or Spark platforms, to handle big spatiotemporal data. Furthermore, considering the energy efficiency requirement in general computation, Field Programmable Gate Array (FPGA) may be a better solution for better energy efficiency when the performance of computation could be similar or better than GPUs and MICs. It is expected that an elastic cloud computing architecture and system that integrates all of GPUs, MICs, and FPGAs could be developed and deployed to support spatiotemporal computing over heterogeneous data types and computational problems.

Elimination of aberrations in wide-aperture magnetoelectrostatic plasma lenses

International Nuclear Information System (INIS)

Butenko, V.I.; Ivanov, B.I.

2003-01-01

A computer model is devised for a Morozov plasma lens, in which the magnetic surfaces are equipotential surfaces of the electric field. Results are presented from numerical modeling of the focusing of ions with allowance for their longitudinal, radial, and azimuthal motions. The strengths and spatial distributions of the magnetic and electric fields are optimized. The methods for removing moment, geometric, and chromatic aberrations are analyzed. The effect of a discrete distribution of the potentials on ion focusing is modeled, and the related aberrations are examined. A computer model of an achromatic two-lens system is considered

Adaptive compensation of aberrations in ultrafast 3D microscopy using a deformable mirror

Science.gov (United States)

Sherman, Leah R.; Albert, O.; Schmidt, Christoph F.; Vdovin, Gleb V.; Mourou, Gerard A.; Norris, Theodore B.

2000-05-01

3D imaging using a multiphoton scanning confocal microscope is ultimately limited by aberrations of the system. We describe a system to adaptively compensate the aberrations with a deformable mirror. We have increased the transverse scanning range of the microscope by three with compensation of off-axis aberrations.We have also significantly increased the longitudinal scanning depth with compensation of spherical aberrations from the penetration into the sample. Our correction is based on a genetic algorithm that uses second harmonic or two-photon fluorescence signal excited by femtosecond pulses from the sample as the enhancement parameter. This allows us to globally optimize the wavefront without a wavefront measurement. To improve the speed of the optimization we use Zernike polynomials as the basis for correction. Corrections can be stored in a database for look-up with future samples.

Some aberrant foraminifera from the shelf sediments of central east coast of India

Digital Repository Service at National Institute of Oceanography (India)

Setty, M.G.A; Almeida, F.