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Sample records for form hemispherical shaped

  1. Free form hemispherical shaped charge

    DOEpatents

    Haselman, L.C. Jr.

    1996-06-04

    A hemispherical shaped charge has been modified such that one side of the hemisphere is spherical and the other is aspherical allowing a wall thickness variation in the liner. A further modification is to use an elongated hemispherical shape. The liner has a thick wall at its pole and a thin wall at the equator with a continually decreasing wall thickness from the pole to the equator. The ratio of the wall thickness from the pole to the equator varies depending on liner material and HE shape. Hemispherical shaped charges have previously been limited to spherical shapes with no variations in wall thicknesses. By redesign of the basic liner thicknesses, the jet properties of coherence, stability, and mass distribution have been significantly improved. 8 figs.

  2. Free form hemispherical shaped charge

    DOEpatents

    Haselman, Jr., Leonard C.

    1996-01-01

    A hemispherical shaped charge has been modified such that one side of the hemisphere is spherical and the other is aspherical allowing a wall thickness variation in the liner. A further modification is to use an elongated hemispherical shape. The liner has a thick wall at its pole and a thin wall at the equator with a continually decreasing wall thickness from the pole to the equator. The ratio of the wall thickness from the pole to the equator varies depending on liner material and HE shape. Hemispherical shaped charges have previously been limited to spherical shapes with no variations in wall thicknesses. By redesign of the basic liner thicknesses, the jet properties of coherence, stability, and mass distribution have been significantly improved.

  3. Particulation in jets from free-form hemispherical shaped charges with copper liners

    SciTech Connect

    Simonson, S.C. III; Haselman, L.C. Jr.; Breithaupt, R.D.

    1995-05-01

    Particulation in free-form hemispherical shaped charge jets is considerably different from that in conical shaped charge jets. From the analysis of the particulation data for 23 experiments covering ten free-form hemi designs with copper liners, it is concluded that jets with higher convergence pressures have delayed particulation, sometimes by as much as a factor of two. Breakup is also found to be design dependent, with free-form hemis have delayed breakup compared with cones. Also, in going from the earlier, boat-tail high explosive (HE) designs to later, more efficient hemispherical HE designs, it is found that particulation is delayed in the tail of the jet. These effects indicate the potential for deeper armor penetration based on control of particulation.

  4. Analytical and numerical investigations into hemisphere-shaped electrostatic sensors.

    PubMed

    Lin, Jun; Chen, Zhong-Sheng; Hu, Zheng; Yang, Yong-Min; Tang, Xin

    2014-07-31

    Electrostatic sensors have been widely used in many applications due to their advantages of low cost and robustness. Their spatial sensitivity and time-frequency characteristics are two important performance parameters. In this paper, an analytical model of the induced charge on a novel hemisphere-shaped electrostatic sensor was presented to investigate its accurate sensing characteristics. Firstly a Poisson model was built for electric fields produced by charged particles. Then the spatial sensitivity and time-frequency response functions were directly derived by the Green function. Finally, numerical calculations were done to validate the theoretical results. The results demonstrate that the hemisphere-shaped sensors have highly 3D-symmetrical spatial sensitivity expressed in terms of elementary function, and the spatial sensitivity is higher and less homogeneous near the hemispherical surface and vice versa. Additionally, the whole monitoring system, consisting of an electrostatic probe and a signal conditioner circuit, acts as a band-pass filter. The time-frequency characteristics depend strongly on the spatial position and velocity of the charged particle, the radius of the probe as well as the equivalent resistance and capacitance of the circuit.

  5. Analytical and Numerical Investigations into Hemisphere-Shaped Electrostatic Sensors

    PubMed Central

    Lin, Jun; Chen, Zhong-Sheng; Hu, Zheng; Yang, Yong-Min; Tang, Xin

    2014-01-01

    Electrostatic sensors have been widely used in many applications due to their advantages of low cost and robustness. Their spatial sensitivity and time-frequency characteristics are two important performance parameters. In this paper, an analytical model of the induced charge on a novel hemisphere-shaped electrostatic sensor was presented to investigate its accurate sensing characteristics. Firstly a Poisson model was built for electric fields produced by charged particles. Then the spatial sensitivity and time-frequency response functions were directly derived by the Green function. Finally, numerical calculations were done to validate the theoretical results. The results demonstrate that the hemisphere-shaped sensors have highly 3D-symmetrical spatial sensitivity expressed in terms of elementary function, and the spatial sensitivity is higher and less homogeneous near the hemispherical surface and vice versa. Additionally, the whole monitoring system, consisting of an electrostatic probe and a signal conditioner circuit, acts as a band-pass filter. The time-frequency characteristics depend strongly on the spatial position and velocity of the charged particle, the radius of the probe as well as the equivalent resistance and capacitance of the circuit. PMID:25090419

  6. The changing shape of Northern Hemisphere summer temperature distributions

    NASA Astrophysics Data System (ADS)

    McKinnon, Karen A.; Rhines, Andrew; Tingley, Martin P.; Huybers, Peter

    2016-08-01

    The occurrence of recent summer temperature extremes in the midlatitudes has raised questions about whether and how the distributions of summer temperature are changing. While it is clear that in most regions the average temperature is increasing, there is less consensus regarding the presence or nature of changes in the shape of the distributions, which can influence the probability of extreme events. Using data from over 4000 weather stations in the Global Historical Climatology Network-Daily database, we quantify the changes in daily maximum and minimum temperature distributions for peak summer in the Northern Hemisphere midlatitudes during 1980-2015 using quantile regression. A large majority (87-88%) of the trends across percentiles and stations can be explained by a shift of the distributions with no change in shape. The remaining variability is summarized through projections onto orthogonal basis functions that are closely related to changes in variance, skewness, and kurtosis. North America and Eurasia show significant shifts in the estimated distributions of daily maximum and minimum temperatures. Although no general change in summer variance is found, variance has regionally increased in Eurasia and decreased in most of North America. Changes in shape that project onto the skewness and kurtosis basis functions have a much smaller spatial scale and are generally insignificant.

  7. Material cutting, shaping, and forming: A compilation

    NASA Technical Reports Server (NTRS)

    1974-01-01

    Information is presented concerning cutting, shaping, and forming of materials, and the equipment and techniques required for utilizing these materials. The use of molds, electrical fields, and mechanical devices are related to forming materials. Material cutting methods by devices including borers and slicers are presented along with chemical techniques. Shaping and fabrication techniques are described for tubing, honeycomb panels, and ceramic structures. The characteristics of the materials are described. Patent information is included.

  8. How are large western hemisphere warm pools formed?

    NASA Astrophysics Data System (ADS)

    Enfield, David B.; Lee, Sang-Ki; Wang, Chunzai

    2006-08-01

    During the boreal summer the Western Hemisphere warm pool (WHWP) stretches from the eastern North Pacific to the tropical North Atlantic and is a key feature of the climate of the Americas and Africa. In the summers following nine El Niño events during 1950-2000, there have been five instances of extraordinarily large warm pools averaging about twice the climatological annual size. These large warm pools have induced a strengthened divergent circulation aloft and have been associated with rainfall anomalies throughout the western hemisphere tropics and subtropics and with more frequent hurricanes. However, following four other El Niño events large warm pools did not develop, such that the mere existence of El Niño during the boreal winter does not provide the basis for predicting an anomalously large warm pool the following summer. In this paper, we find consistency with the hypothesis that large warm pools result from an anomalous divergent circulation forced by sea surface temperature (SST) anomalies in the Pacific, the so-called atmospheric bridge. We also find significant explanations for why large warm pools do not always develop. If the El Niño event ends early in the eastern Pacific, the Pacific warm anomaly lacks the persistence needed to force the atmospheric bridge and the Atlantic portion of the warm pool remains normal. If SST anomalies in the eastern Pacific do not last much beyond February of the following year, then the eastern North Pacific portion of the warm pool remains normal. The overall strength of the Pacific El Niño does not appear to be a critical factor. We also find that when conditions favor a developing atmospheric bridge and the winter atmosphere over the North Atlantic conforms to a negative North Atlantic Oscillation (NAO) pattern (as in 1957-58 and 1968-69), the forcing is reinforced and the warm pool is stronger. On the other hand, if a positive NAO pattern develops the warm pool may remain normal even if other circumstances

  9. Cup-Shaped Superparamagnetic Hemispheres for Size-Selective Cell Filtration

    NASA Astrophysics Data System (ADS)

    Kim, Hyonchol; Terazono, Hideyuki; Takei, Hiroyuki; Yasuda, Kenji

    2014-09-01

    We propose a new method of size separation of cells exploiting precisely size-controlled hemispherical superparamagnetic microparticles. A three-layered structure of a 2-nm nickel layer inserted between 15-nm silicon dioxide layers was formed on polystyrene cast spheres by vapor deposition. The polystyrene was then removed by burning and the hemispherical superparamagnetic microparticles, ``magcups'', were obtained. The standard target cells (CCRF-CEM, 12 +/- 2 μm) were mixed with a set of different sizes of the fabricated magcups, and we confirmed that the cells were captured in the magcups having cavities larger than 15 μm in diameter, and then gathered by magnetic force. The collected cells were grown in a culture medium without any damage. The results suggest that this method is quick, simple and non-invasive size separation of target cells.

  10. Aerodynamic Shape Optimization Based on Free-form Deformation

    NASA Technical Reports Server (NTRS)

    Samareh, Jamshid A.

    2004-01-01

    This paper presents a free-form deformation technique suitable for aerodynamic shape optimization. Because the proposed technique is independent of grid topology, we can treat structured and unstructured computational fluid dynamics grids in the same manner. The proposed technique is an alternative shape parameterization technique to a trivariate volume technique. It retains the flexibility and freedom of trivariate volumes for CFD shape optimization, but it uses a bivariate surface representation. This reduces the number of design variables by an order of magnitude, and it provides much better control for surface shape changes. The proposed technique is simple, compact, and efficient. The analytical sensitivity derivatives are independent of the design variables and are easily computed for use in a gradient-based optimization. The paper includes the complete formulation and aerodynamics shape optimization results.

  11. Alternative form for the pseudo-Voigt peak shape

    NASA Astrophysics Data System (ADS)

    Végh, János

    2005-05-01

    A number of different approximations are in use in different fields of spectroscopy for calculating the Voigt line shape. The most popular among them is the pseudo-Voigt line shape. Its main disadvantage is that it is quite complicated to conclude from its parameters the natural width of the line and the spectrometer contribution. Furthermore there exists no simple possibility to replace the line shape with a more accurate approximation to the Voigt shape. An alternative form for this peak shape is presented, which is parametrized with the natural width and spectrometer contribution and transparently maps these parameters to the parameters "Gauss/Lorentz mixing ratio" and "total width." This representation keeps the calculation simple and quick. Furthermore it allows a smooth transition to the more accurate Voigt approximations.

  12. Electrohydraulic Forming of Near Net Shape Automotive Panels

    SciTech Connect

    2009-01-01

    This factsheet describes a research project whose goal is to develop the electrohydraulic forming (EHF) process as a near net shape automotive panel manufacturing technology that simultaneously reduces the energy embedded in vehicles and the energy consumed while producing automotive structures.

  13. An Interdisciplinary Analysis of Microteaching Evaluation Forms: How Peer Feedback Forms Shape What Constitutes "Good Teaching"

    ERIC Educational Resources Information Center

    Vander Kloet, Marie Annette; Chugh, Brige Paul

    2012-01-01

    Microteaching, a standard method for developing teaching skills, places high importance on peer feedback, which is guided by post-session feedback forms. This paper focuses on how feedback forms can shape what becomes understood as important to teaching. A sample of 10 microteaching evaluation forms drawn from North American postsecondary…

  14. Analysis of the Dynamic Sensitivity of Hemisphere-Shaped Electrostatic Sensors’ Circular Array for Charged Particle Monitoring

    PubMed Central

    Tang, Xin; Chen, Zhong-Sheng; Li, Yue; Hu, Zheng; Yang, Yong-Min

    2016-01-01

    Electrostatic sensor arrays (ESAs) are promising in industrial applications related to charged particle monitoring. Sensitivity is a fundamental and commonly-used sensing characteristic of an ESA. However, the usually used spatial sensitivity, which is called static sensitivity here, is not proper for moving particles or capable of reflecting array signal processing algorithms integrated in an ESA. Besides, reports on ESAs for intermittent particles are scarce yet, especially lacking suitable array signal processing algorithms. To solve the problems, the dynamic sensitivity of ESA is proposed, and a hemisphere-shaped electrostatic sensors’ circular array (HSESCA) along with its application in intermittent particle monitoring are taken as an example. In detail, a sensing model of the HSESCA is built. On this basis, its array signals are analyzed; the dynamic sensitivity is thereupon defined by analyzing the processing of the array signals. Besides, a component extraction-based array signal processing algorithm for intermittent particles is proposed, and the corresponding dynamic sensitivity is analyzed quantitatively. Moreover, simulated and experimental results are discussed, which validate the accuracy of the models and the effectiveness of the relevant approaches. The proposed dynamic sensitivity of ESA, as well as the array signal processing algorithm are expected to provide references in modeling, designing and using ESAs. PMID:27589767

  15. Analysis of the Dynamic Sensitivity of Hemisphere-Shaped Electrostatic Sensors' Circular Array for Charged Particle Monitoring.

    PubMed

    Tang, Xin; Chen, Zhong-Sheng; Li, Yue; Hu, Zheng; Yang, Yong-Min

    2016-08-31

    Electrostatic sensor arrays (ESAs) are promising in industrial applications related to charged particle monitoring. Sensitivity is a fundamental and commonly-used sensing characteristic of an ESA. However, the usually used spatial sensitivity, which is called static sensitivity here, is not proper for moving particles or capable of reflecting array signal processing algorithms integrated in an ESA. Besides, reports on ESAs for intermittent particles are scarce yet, especially lacking suitable array signal processing algorithms. To solve the problems, the dynamic sensitivity of ESA is proposed, and a hemisphere-shaped electrostatic sensors' circular array (HSESCA) along with its application in intermittent particle monitoring are taken as an example. In detail, a sensing model of the HSESCA is built. On this basis, its array signals are analyzed; the dynamic sensitivity is thereupon defined by analyzing the processing of the array signals. Besides, a component extraction-based array signal processing algorithm for intermittent particles is proposed, and the corresponding dynamic sensitivity is analyzed quantitatively. Moreover, simulated and experimental results are discussed, which validate the accuracy of the models and the effectiveness of the relevant approaches. The proposed dynamic sensitivity of ESA, as well as the array signal processing algorithm are expected to provide references in modeling, designing and using ESAs.

  16. On The Influence Of The Yield Locus Shape In The Simulation Of Sheet Stretch Forming

    NASA Astrophysics Data System (ADS)

    Mattiasson, Kjell; Sigvant, Mats

    2005-08-01

    In the present paper results from an ongoing project at Volvo Cars and Chalmers University will be presented. The object of this project is to reduce the gap between the research frontier and the industrial practice concerning material modeling. One of the targets of the project is to identify a yield function, which can fulfill the special industrial demands concerning accuracy, easy parameter identification, and computational efficiency. Lately, some new yield functions have been presented, which seem to satisfy these demands. These yield functions belong to a group of non-quadratic yield criteria, sometimes referred to as "the Hosford family". These criteria are characterized by a stress exponent, which has been shown to have a strong coupling to the crystallographic structure of the material. The present paper addresses the issue of how the main parameters controlling the shape of the yield locus are influencing the material flow in sheet forming simulations. Since it is a well established fact that the shape of the yield locus has its major influence in pure stretch forming, i.e. on the right hand side of a FLD, we have chosen stretch forming with a hemispherical punch as a simple demonstration example. The M-K approach will also be used as a means to try to explain some of the observed phenomena.

  17. On The Influence Of The Yield Locus Shape In The Simulation Of Sheet Stretch Forming

    SciTech Connect

    Mattiasson, Kjell; Sigvant, Mats

    2005-08-05

    In the present paper results from an ongoing project at Volvo Cars and Chalmers University will be presented. The object of this project is to reduce the gap between the research frontier and the industrial practice concerning material modeling. One of the targets of the project is to identify a yield function, which can fulfill the special industrial demands concerning accuracy, easy parameter identification, and computational efficiency. Lately, some new yield functions have been presented, which seem to satisfy these demands. These yield functions belong to a group of non-quadratic yield criteria, sometimes referred to as 'the Hosford family'. These criteria are characterized by a stress exponent, which has been shown to have a strong coupling to the crystallographic structure of the material. The present paper addresses the issue of how the main parameters controlling the shape of the yield locus are influencing the material flow in sheet forming simulations. Since it is a well established fact that the shape of the yield locus has its major influence in pure stretch forming, i.e. on the right hand side of a FLD, we have chosen stretch forming with a hemispherical punch as a simple demonstration example. The M-K approach will also be used as a means to try to explain some of the observed phenomena.

  18. Near net shape forming of advanced structural ceramic devices

    NASA Astrophysics Data System (ADS)

    Liu, Hao-Chih

    This research applied a combination of rapid prototyping techniques and ceramic gelcasting processes in the design and manufacturing of advanced structural ceramic components that cannot be fabricated by other shape-forming processes. An Assembly Mold SDM process, a derivative process of Shape Deposition Manufacturing, was adopted along with modified gelcasting with great success. The fabricated gas turbine rotors, inlet nozzles, and mesoscale burner arrays have demonstrated superior shape accuracy, mechanical strength, and surface smoothness with a feature size of 200 mum. The design concepts and functionalities of the ceramic devices were verified with performance tests. The shape complexity and surface quality of ceramic parts have been further improved by the use of a mold assembly made of a low melting temperature metal alloy. The introduction of metal alloy required modifications in the mold design, machining procedure, and ceramic processing. A complete shape forming process (from slurry to final parts) was developed for the low melting temperature metal alloy. In addition, the choice of ceramic material now includes SiC, which is critical to the development of micro heat exchangers. Forty-channel, high-aspect-ratio structured SiC heat exchangers were fabricated, and the thermal conductivity value of SiC was found to be comparable to that of steel. The catalyst deposition and ceramic precursor impregnation processes were proposed to enable use of the SiC heat exchangers as micro reactors. Micro-electro-mechanical-systems (MEMS)-related techniques such as SU-8 deep photolithography and polydimethylsiloxane (PDMS) soft lithography were combined with gelcasting to make micro patterns on structural ceramics. A feature size of 125 mum and aspect ratio of 8 have been achieved in the preliminary experiments. Based on the fabricated ceramic devices, a graphical method to characterize the shape attributes of complex-shaped components was proposed and used to compare

  19. Form equals function? Bacterial shape and its consequences for pathogenesis.

    PubMed

    Dworkin, Jonathan

    2010-11-01

    Bacteria exhibit a wide variety of morphologies. This could simply be a consequence of an elaboration of bacterial cellular architecture akin to the famous decorative but not structurally essential Spandrels in the Basilica di San Marco in Venice that are a side-effect of an adaptation, rather than a direct product of natural selection. However, it is more likely that particular morphologies facilitate a specific function in cellular physiology. Two recent publications including one in this issue of Molecular Microbiology and another in Cell provide new insights into the molecular basis for the helical shape of the bacterium Helicobacter pylori and the role of this shape in pathogenesis. They identify a novel endopeptidase that is necessary to generate the helical shape by processing the peptidoglycan and report that catalytically inactive mutants lead to defects in colonization that appear to be independent of an effect on cellular motility. Here, we put these findings in the context of some of what is known about peptidoglycan and cell shape and suggest that the role of this endopeptidase in forming coccoid morphology may be critical for pathogenesis.

  20. Process for forming shaped group II-VI semiconductor nanocrystals, and product formed using process

    DOEpatents

    Alivisatos, A. Paul; Peng, Xiaogang; Manna, Liberato

    2001-01-01

    A process for the formation of shaped Group II-VI semiconductor nanocrystals comprises contacting the semiconductor nanocrystal precursors with a liquid media comprising a binary mixture of phosphorus-containing organic surfactants capable of promoting the growth of either spherical semiconductor nanocrystals or rod-like semiconductor nanocrystals, whereby the shape of the semiconductor nanocrystals formed in said binary mixture of surfactants is controlled by adjusting the ratio of the surfactants in the binary mixture.

  1. Process for forming shaped group III-V semiconductor nanocrystals, and product formed using process

    DOEpatents

    Alivisatos, A. Paul; Peng, Xiaogang; Manna, Liberato

    2001-01-01

    A process for the formation of shaped Group III-V semiconductor nanocrystals comprises contacting the semiconductor nanocrystal precursors with a liquid media comprising a binary mixture of phosphorus-containing organic surfactants capable of promoting the growth of either spherical semiconductor nanocrystals or rod-like semiconductor nanocrystals, whereby the shape of the semiconductor nanocrystals formed in said binary mixture of surfactants is controlled by adjusting the ratio of the surfactants in the binary mixture.

  2. How language production shapes language form and comprehension

    PubMed Central

    MacDonald, Maryellen C.

    2012-01-01

    Language production processes can provide insight into how language comprehension works and language typology—why languages tend to have certain characteristics more often than others. Drawing on work in memory retrieval, motor planning, and serial order in action planning, the Production-Distribution-Comprehension (PDC) account links work in the fields of language production, typology, and comprehension: (1) faced with substantial computational burdens of planning and producing utterances, language producers implicitly follow three biases in utterance planning that promote word order choices that reduce these burdens, thereby improving production fluency. (2) These choices, repeated over many utterances and individuals, shape the distributions of utterance forms in language. The claim that language form stems in large degree from producers' attempts to mitigate utterance planning difficulty is contrasted with alternative accounts in which form is driven by language use more broadly, language acquisition processes, or producers' attempts to create language forms that are easily understood by comprehenders. (3) Language perceivers implicitly learn the statistical regularities in their linguistic input, and they use this prior experience to guide comprehension of subsequent language. In particular, they learn to predict the sequential structure of linguistic signals, based on the statistics of previously-encountered input. Thus, key aspects of comprehension behavior are tied to lexico-syntactic statistics in the language, which in turn derive from utterance planning biases promoting production of comparatively easy utterance forms over more difficult ones. This approach contrasts with classic theories in which comprehension behaviors are attributed to innate design features of the language comprehension system and associated working memory. The PDC instead links basic features of comprehension to a different source: production processes that shape language form

  3. Feeling form: the neural basis of haptic shape perception

    PubMed Central

    Kim, Sung Soo; Thakur, Pramodsingh H.; Bensmaia, Sliman J.

    2015-01-01

    The tactile perception of the shape of objects critically guides our ability to interact with them. In this review, we describe how shape information is processed as it ascends the somatosensory neuraxis of primates. At the somatosensory periphery, spatial form is represented in the spatial patterns of activation evoked across populations of mechanoreceptive afferents. In the cerebral cortex, neurons respond selectively to particular spatial features, like orientation and curvature. While feature selectivity of neurons in the earlier processing stages can be understood in terms of linear receptive field models, higher order somatosensory neurons exhibit nonlinear response properties that result in tuning for more complex geometrical features. In fact, tactile shape processing bears remarkable analogies to its visual counterpart and the two may rely on shared neural circuitry. Furthermore, one of the unique aspects of primate somatosensation is that it contains a deformable sensory sheet. Because the relative positions of cutaneous mechanoreceptors depend on the conformation of the hand, the haptic perception of three-dimensional objects requires the integration of cutaneous and proprioceptive signals, an integration that is observed throughout somatosensory cortex. PMID:26581869

  4. Form, shape and function: segmented blood flow in the choriocapillaris

    NASA Astrophysics Data System (ADS)

    Zouache, M. A.; Eames, I.; Klettner, C. A.; Luthert, P. J.

    2016-10-01

    The development of fluid transport systems was a key event in the evolution of animals and plants. While within vertebrates branched geometries predominate, the choriocapillaris, which is the microvascular bed that is responsible for the maintenance of the outer retina, has evolved a planar topology. Here we examine the flow and mass transfer properties associated with this unusual geometry. We show that as a result of the form of the choriocapillaris, the blood flow is decomposed into a tessellation of functional vascular segments of various shapes delineated by separation surfaces across which there is no flow, and in the vicinity of which the transport of passive substances is diffusion-limited. The shape of each functional segment is determined by the distribution of arterioles and venules and their respective relative flow rates. We also show that, remarkably, the mass exchange with the outer retina is a function of the shape of each functional segment. In addition to introducing a novel framework in which the structure and function of the metabolite delivery system to the outer retina may be investigated in health and disease, the present work provides a general characterisation of the flow and transfers in multipole Hele-Shaw configurations.

  5. Form, shape and function: segmented blood flow in the choriocapillaris

    PubMed Central

    Zouache, M. A.; Eames, I.; Klettner, C. A.; Luthert, P. J.

    2016-01-01

    The development of fluid transport systems was a key event in the evolution of animals and plants. While within vertebrates branched geometries predominate, the choriocapillaris, which is the microvascular bed that is responsible for the maintenance of the outer retina, has evolved a planar topology. Here we examine the flow and mass transfer properties associated with this unusual geometry. We show that as a result of the form of the choriocapillaris, the blood flow is decomposed into a tessellation of functional vascular segments of various shapes delineated by separation surfaces across which there is no flow, and in the vicinity of which the transport of passive substances is diffusion-limited. The shape of each functional segment is determined by the distribution of arterioles and venules and their respective relative flow rates. We also show that, remarkably, the mass exchange with the outer retina is a function of the shape of each functional segment. In addition to introducing a novel framework in which the structure and function of the metabolite delivery system to the outer retina may be investigated in health and disease, the present work provides a general characterisation of the flow and transfers in multipole Hele-Shaw configurations. PMID:27779198

  6. Prediction of Multipreform Shapes in Warm Forming with Experimental Verification

    NASA Astrophysics Data System (ADS)

    Kong, T. F.; Chan, L. C.

    2015-02-01

    This study uses a computer-aided simulation approach to predict the multipreform shapes of warm-forming intricate components. Nearly 100% of the scraps of primary hollow preforms are used to make secondary hollow preforms. This study simultaneously fabricates the AISI 316L stainless steel watch bezel by using scraps from the corresponding watch case. The appropriate preforms are designed with the aid of computer simulation such that die filling is completed, flash is reduced, and forming load is decreased. The specimens were prepared by custom-made tooling to verify the simulation results. Furthermore, the forming facilities are specially configured to carry out the physical experiments. Engineers eventually gain a better understanding of the warm-forming process using computer simulation. Moreover, they are able to design accurate preforms and fully utilize the material, which leads to a 50% improvement of the material utilization rate. The full material utilization also saves 40% and 20% of the total production cost and time, respectively.

  7. Electrohydraulic Forming of Near-Net Shape Automotive Panels

    SciTech Connect

    Golovaschenko, Sergey F.

    2013-09-26

    The objective of this project was to develop the electrohydraulic forming (EHF) process as a near-net shape automotive panel manufacturing technology that simultaneously reduces the energy embedded in vehicles and the energy consumed while producing automotive structures. Pulsed pressure is created via a shockwave generated by the discharge of high voltage capacitors through a pair of electrodes in a liquid-filled chamber. The shockwave in the liquid initiated by the expansion of the plasma channel formed between two electrodes propagates towards the blank and causes the blank to be deformed into a one-sided die cavity. The numerical model of the EHF process was validated experimentally and was successfully applied to the design of the electrode system and to a multi-electrode EHF chamber for full scale validation of the process. The numerical model was able to predict stresses in the dies during pulsed forming and was validated by the experimental study of the die insert failure mode for corner filling operations. The electrohydraulic forming process and its major subsystems, including durable electrodes, an EHF chamber, a water/air management system, a pulse generator and integrated process controls, were validated to be capable to operate in a fully automated, computer controlled mode for forming of a portion of a full-scale sheet metal component in laboratory conditions. Additionally, the novel processes of electrohydraulic trimming and electrohydraulic calibration were demonstrated at a reduced-scale component level. Furthermore, a hybrid process combining conventional stamping with EHF was demonstrated as a laboratory process for a full-scale automotive panel formed out of AHSS material. The economic feasibility of the developed EHF processes was defined by developing a cost model of the EHF process in comparison to the conventional stamping process.

  8. Form follows function: a computational simulation exercise on bone shape forming and conservation.

    PubMed

    Mittag, U; Kriechbaumer, A; Bartsch, M; Rittweger, J

    2015-06-01

    The present paper explores whether the shape of long bone shafts can be explained as a mere result of mechano-adapation. A computer simulation study was conducted in order to investigate adaptation processes of bone-like structures under load patterns comparable to those acting on the diaphysis of long bones. The aim of the study was to have a deeper look into the relationship between typical loading patterns and resulting bone shape and structure. The simulations are based on a mechanistic model approach for mechano-transduction and bone transformation. Results of the simulations are that axial torsion around the long axis is important for the evolvement and maintenance of tube-like structures. Of note such structures can form from a variety of starting geometries, provided that axial torsion is present. The selection of the set-point parameter for the regulation of load adapted bone transformation has an impact on the final structure as well. In conclusion, the present study confirms the mechanical environment's potential to generate shaft-like structures and demonstrates the respective boundary conditions.

  9. Form follows function: a computational simulation exercise on bone shape forming and conservation

    PubMed Central

    Mittag, U.; Kriechbaumer, A.; Bartsch, M.; Rittweger, J.

    2015-01-01

    The present paper explores whether the shape of long bone shafts can be explained as a mere result of mechano-adapation. A computer simulation study was conducted in order to investigate adaptation processes of bone-like structures under load patterns comparable to those acting on the diaphysis of long bones. The aim of the study was to have a deeper look into the relationship between typical loading patterns and resulting bone shape and structure. The simulations are based on a mechanistic model approach for mechano-transduction and bone transformation. Results of the simulations are that axial torsion around the long axis is important for the evolvement and maintenance of tube-like structures. Of note such structures can form from a variety of starting geometries, provided that axial torsion is present. The selection of the set-point parameter for the regulation of load adapted bone transformation has an impact on the final structure as well. In conclusion, the present study confirms the mechanical environment’s potential to generate shaft-like structures and demonstrates the respective boundary conditions. PMID:26032215

  10. Auto-sensuous shapes: prototypes for creative forms.

    PubMed

    Charles, M

    2001-09-01

    The author looks at some of the more normative, adaptive, and creative aspects of what have been called 'autistic' or 'auto-sensuous' shapes by Tustin and others. She explores the construct from several frameworks, including the literature on early sensory experience and that on the empathic attunement between infant and caretaker in which interpersonal rhythms and meanings are built. The views of Bion and Matte-Blanco are utilized to help explore the processes by which meaning is created from experience, while the works of Segal and Milner are used to focus more explicitly on the role of symbol formation in the creative process. Finally, it is suggested that these auto-sensuous shapes can become prototypes for creative endeavours, including the creative process we call psychoanalysis. The author uses examples from her own experience in deriving pattern from basic sensory experience, toward the creation of poetry, drawings, and the establishment of attunement and 'meaning-making' within the analytic setting.

  11. Dip molding to form intricately-shaped medical elastomer devices

    NASA Technical Reports Server (NTRS)

    Broyles, H. F.

    1975-01-01

    Preshaped mandrel mounted on rotating mechanism is partically immersed in tank filled with liquid elastomer. While mandrel rotates, elastomer film forms om mandrel surface due to surface tension and capillary behavior of liquid. Devices with well-defined flanges can be made using process.

  12. Effects of Processing Parameters on the Forming Quality of C-Shaped Thermosetting Composite Laminates in Hot Diaphragm Forming Process

    NASA Astrophysics Data System (ADS)

    Bian, X. X.; Gu, Y. Z.; Sun, J.; Li, M.; Liu, W. P.; Zhang, Z. G.

    2013-10-01

    In this study, the effects of processing temperature and vacuum applying rate on the forming quality of C-shaped carbon fiber reinforced epoxy resin matrix composite laminates during hot diaphragm forming process were investigated. C-shaped prepreg preforms were produced using a home-made hot diaphragm forming equipment. The thickness variations of the preforms and the manufacturing defects after diaphragm forming process, including fiber wrinkling and voids, were evaluated to understand the forming mechanism. Furthermore, both interlaminar slipping friction and compaction behavior of the prepreg stacks were experimentally analyzed for showing the importance of the processing parameters. In addition, autoclave processing was used to cure the C-shaped preforms to investigate the changes of the defects before and after cure process. The results show that the C-shaped prepreg preforms with good forming quality can be achieved through increasing processing temperature and reducing vacuum applying rate, which obviously promote prepreg interlaminar slipping process. The process temperature and forming rate in hot diaphragm forming process strongly influence prepreg interply frictional force, and the maximum interlaminar frictional force can be taken as a key parameter for processing parameter optimization. Autoclave process is effective in eliminating voids in the preforms and can alleviate fiber wrinkles to a certain extent.

  13. Advanced method and processing technology for complicated shape airframe part forming

    NASA Technical Reports Server (NTRS)

    Miodushevsky, P. V.; Rajevskaya, G. A.

    1994-01-01

    Slow deformation modes of forming give considerably higher residual fatigue life of the airframe part. It has experimentally proven that fatigue life of complicated shape integral airframe panels made of high strength aluminum alloys is significantly increased after creep deformation process. To implement the slow deformation mode forming methods, universal automated equipment was developed. Multichannel forming systems provide high accuracy of airframe part shape eliminating residual stresses and spring effect. Forming process multizone control technology was developed and experimentally proved that static/fatigue properties of formed airframe parts are increased.

  14. An Illustrated Key to the Cyst-Forming Genera and Species of Heteroderidae in the Western Hemisphere with Species Morphometrics and Distribution

    PubMed Central

    Mulvey, R. H.; Golden, A. Morgan

    1983-01-01

    Diagnoses of the cyst-forming genera of Heteroderidae (viz., Heterodera, Sarisodera, Globodera, Punctodera, Cactodera, and Dolichodera) and distribution and morphometrics of the 34 known cyst species in the Western Hemisphere are presented along with an illustrated key for the identification of these genera and species. The key is based mainly on cysts and larvae, and important morphological and diagnostic features are extensively shown by LM and SEM illustrations. The genus Bidera is placed as a new synonym under the genus Heterodera. PMID:19295764

  15. Right Hemisphere Brain Damage

    MedlinePlus

    ... Language and Swallowing / Disorders and Diseases Right Hemisphere Brain Damage [ en Español ] What is right hemisphere brain ... right hemisphere brain damage ? What is right hemisphere brain damage? Right hemisphere brain damage (RHD) is damage ...

  16. Novel free-form hohlraum shape design and optimization for laser-driven inertial confinement fusion

    SciTech Connect

    Jiang, Shaoen; Jing, Longfei Ding, Yongkun; Huang, Yunbao

    2014-10-15

    The hohlraum shape attracts considerable attention because there is no successful ignition method for laser-driven inertial confinement fusion at the National Ignition Facility. The available hohlraums are typically designed with simple conic curves, including ellipses, parabolas, arcs, or Lame curves, which allow only a few design parameters for the shape optimization, making it difficult to improve the performance, e.g., the energy coupling efficiency or radiation drive symmetry. A novel free-form hohlraum design and optimization approach based on the non-uniform rational basis spline (NURBS) model is proposed. In the present study, (1) all kinds of hohlraum shapes can be uniformly represented using NURBS, which is greatly beneficial for obtaining the optimal available hohlraum shapes, and (2) such free-form uniform representation enables us to obtain an optimal shape over a large design domain for the hohlraum with a more uniform radiation and higher drive temperature of the fuel capsule. Finally, a hohlraum is optimized and evaluated with respect to the drive temperature and symmetry at the Shenguang III laser facility in China. The drive temperature and symmetry results indicate that such a free-form representation is advantageous over available hohlraum shapes because it can substantially expand the shape design domain so as to obtain an optimal hohlraum with high performance.

  17. Spray Forming of NiTi and NiTiPd Shape-Memory Alloys

    NASA Technical Reports Server (NTRS)

    Mabe, James; Ruggeri, Robert; Noebe, Ronald

    2008-01-01

    In the work to be presented, vacuum plasma spray forming has been used as a process to deposit and consolidate prealloyed NiTi and NiTiPd powders into near net shape actuators. Testing showed that excellent shape memory behavior could be developed in the deposited materials and the investigation proved that VPS forming could be a means to directly form a wide range of shape memory alloy components. The results of DSC characterization and actual actuation test results will be presented demonstrating the behavior of a Nitinol 55 alloy and a higher transition temperature NiTiPd alloy in the form of torque tube actuators that could be used in aircraft and aerospace controls.

  18. Hemispheric Amphigory.

    ERIC Educational Resources Information Center

    Youngblood, Michael

    1981-01-01

    Reviewing some empirical studies on brain hemisphere functions, the author concludes that though the brain is lateralized for specific tasks, this fact has no necessary bearing on educational methodology. He asserts that we do not yet know enough to label and teach art as a "right brain" activity. (Author/SJL)

  19. Europa's Leading Hemisphere

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This image of Europa's leading hemisphere was obtained by the solid state imaging (CCD) system on board NASA's Galileo spacecraft during its seventh orbit of Jupiter. In the upper left part of the image is Tyre, a multi-ringed structure that may have formed as a result of an ancient impact. Also visible are numerous lineaments that extend for over 1000 kilometers. The limb, or edge, of Europa in this image can be used by scientists to constrain the radius and shape of the satellite. North is to the top of the picture and the sun illuminates the surface from the right. The image, centered at -40 latitude and 180 longitude, covers an area approximately 2000 by 1300 kilometers. The finest details that can be discerned in this picture are about 6.6 kilometers across. The images were taken on April 3, 1997 at 17 hours, 42 minutes, 19 seconds Universal Time when the spacecraft was at a range of 31,8628 kilometers.

    The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  20. Method of and apparatus for forming long metal tubing stock to tapered shape

    SciTech Connect

    Yoshida, K.

    1985-02-12

    The method and apparatus permit a relatively long metal tubing stock to be finished to any desired tapered shape through a single-pass operation. The apparatus is provided in the form of a tandem configuration including any number of individual swaging units each having the identical construction including the same working parts and assemblies. The grooved roll arrangement associated with the tandem-configured swaging units is used as a preliminary step, and forms an initial metal tubing stock to a multiple-stepped shape.

  1. Insect form vision as one potential shaping force of spider web decoration design.

    PubMed

    Cheng, R-C; Yang, E-C; Lin, C-P; Herberstein, M E; Tso, I-M

    2010-03-01

    Properties of prey sensory systems are important factors shaping the design of signals generated by organisms exploiting them. In this study we assessed how prey sensory preference affected the exploiter signal design by investigating the evolutionary relationship and relative attractiveness of linear and cruciate form web decorations built by Argiope spiders. Because insects have an innate preference for bilaterally symmetrical patterns, we hypothesized that cruciate form decorations were evolved from linear form due to their higher visual attractiveness to insects. We first reconstructed a molecular phylogeny of the Asian members of the genus Argiope using mitochondrial markers to infer the evolutionary relationship of two decoration forms. Results of ancestral character state reconstruction showed that the linear form was ancestral and the cruciate form derived. To evaluate the luring effectiveness of two decoration forms, we performed field experiments in which the number and orientation of decoration bands were manipulated. Decoration bands arranged in a cruciate form were significantly more attractive to insects than those arranged in a linear form, no matter whether they were composed of silks or dummies. Moreover, dummy decoration bands arranged in a cruciate form attracted significantly more insects than those arranged in a vertical/horizontal form. Such results suggest that pollinator insects' innate preference for certain bilateral or radial symmetrical patterns might be one of the driving forces shaping the arrangement pattern of spider web decorations.

  2. An unusual form of reaction wood in Koromiko [Hebe salicifolia G. Forst. (Pennell)], a southern hemisphere angiosperm.

    PubMed

    Kojima, Miho; Becker, Verena K; Altaner, Clemens M

    2012-02-01

    Koromiko [Hebe salicifolia G. Forst. (Pennell)] is a woody angiosperm native to New Zealand and Chile. Hebe spp. belong to the otherwise herbaceous family Plantaginaceae in the order Lamiales. Reaction wood exerting expansional forces was found on the lower side of leaning H. salicifolia stems. Such reaction wood is atypical for angiosperms, which commonly form contracting reaction wood on the upper side of leaning stems. Reaction wood typical for angiosperms is formed by species in other families in the order Lamiales. This suggests that the form of reaction wood is specific to the family level. Functionally the reaction wood of H. salicifolia is similar to that found in gymnosperms, which both act by pushing. However, their chemical, anatomical and physical characteristics are different. Typical features of reaction wood present in gymnosperms such as high density, thick-walled rounded cells and the presence of (1 → 4)-β-galactan in the secondary cell wall layer are absent in H. salicifolia reaction wood. Reaction wood of H. salicifolia varies from normal wood in having a higher microfibril angle, which is likely to determine the direction of generated maturation stresses.

  3. Shape Beyond Recognition: Form-derived Directionality and its Effects on Visual Attention and Motion Perception

    PubMed Central

    Sigurdardottir, Heida M.; Michalak, Suzanne M.; Sheinberg, David L.

    2013-01-01

    The shape of an object restricts its movements and therefore its future location. The rules governing selective sampling of the environment likely incorporate any available data, including shape, that provide information about where important things are going to be in the near future so that the object can be located, tracked, and sampled for information. We asked people to assess in which direction several novel objects pointed or directed them. With independent groups of people, we investigated whether their attention and sense of motion were systematically biased in this direction. Our work shows that nearly any novel object has intrinsic directionality derived from its shape. This shape information is swiftly and automatically incorporated into the allocation of overt and covert visual orienting and the detection of motion, processes which themselves are inherently directional. The observed connection between form and space suggests that shape processing goes beyond recognition alone and may help explain why shape is a relevant dimension throughout the visual brain. PMID:23565670

  4. FUNCTION FOLLOWS FORM: ACTIVATION OF SHAPE & FUNCTION FEATURES DURING OBJECT IDENTIFICATION

    PubMed Central

    Yee, Eiling; Huffstetler, Stacy; Thompson-Schill, Sharon L.

    2011-01-01

    Most theories of semantic memory characterize knowledge of a given object as comprising a set of semantic features. But how does conceptual activation of these features proceed during object identification? We present the results of a pair of experiments that demonstrate that object recognition is a dynamically unfolding process in which function follows form. We used eye movements to explore whether activating one object’s concept leads to the activation of others that share perceptual (shape) or abstract (function) features. Participants viewed four-picture displays and clicked on the picture corresponding to a heard word. In critical trials, the conceptual representation of one of the objects in the display was similar in shape or function (i.e., its purpose) to the heard word. Importantly, this similarity was not apparent in the visual depictions (e.g., for the target “frisbee,” the shape-related object was a triangular slice of pizza – a shape that a frisbee cannot take); preferential fixations on the related object were therefore attributable to overlap of the conceptual representations on the relevant features. We observed relatedness effects for both shape and function, but shape effects occurred earlier than function effects. We discuss the implications of these findings for current accounts of the representation of semantic memory. PMID:21417543

  5. Words, Hemispheres, and Dissociable Subsystems: The Effects of Exposure Duration, Case Alternation, Priming, and Continuity of Form on Word Recognition in the Left and Right Visual Fields

    ERIC Educational Resources Information Center

    Ellis, Andrew W.; Ansorge, Lydia; Lavidor, Michal

    2007-01-01

    Three experiments explore aspects of the dissociable neural subsystems theory of hemispheric specialisation proposed by Marsolek and colleagues, and in particular a study by [Deason, R. G., & Marsolek, C. J. (2005). A critical boundary to the left-hemisphere advantage in word processing. "Brain and Language," 92, 251-261]. Experiment 1A showed…

  6. Effect of temper rolling on final shape defects in a V-section roll forming process

    NASA Astrophysics Data System (ADS)

    Abvabi, Akbar; Rolfe, Bernard; Hodgson, Peter D.; Weiss, Matthias

    2013-12-01

    Roll forming is a continuous process in which a flat strip is shaped to the desired profile by sequential bending in a series of roll stands. Because of the large variety of applications of roll forming in the industry, Finite Element Analysis (FEA) is increasingly utilized for roll forming process design. Bending is the dominant deformation mode in roll forming. Sheet materials used in this process are generally temper rolled, roller- or tension- leveled. These processes introduce residual stresses into the material, and recent studies have shown that those affect the material behavior in bending. In this study a numerical model of the temper rolling (skin passing) process was used to determine a residual stress distribution in a dual phase, DP780, steel strip. A 5-stand roll forming process for the forming of a V-section was modeled, and the effect of various thickness reduction levels in the temper rolling process on the final shape defects was analyzed. The results show that a small thickness reduction in the temper rolling process decreases the maximum bow height but the final springback angle increases. It is also shown that reasonable model accuracy can be achieved by including the residual stress information due to temper rolling as initial condition in the numerical modeling of a roll forming process.

  7. Apparatus and method for forming a workpiece surface into a non-rotationally symmetric shape

    DOEpatents

    Dow, Thomas A.; Garrard, Kenneth P.; Moorefield, II, George M.; Taylor, Lauren W.

    1995-11-21

    A turning machine includes a controller for generating both aspherical and non-symmetrical shape components defining the predetermined shape, and a controller for controlling a spindle and a positionable cutting blade to thereby form a predetermined non-rotationally symmetric shape in a workpiece surface. The apparatus includes a rotatable spindle for rotatably mounting the workpiece about an axis, a spindle encoder for sensing an angular position of the rotating workpiece, the cutting blade, and radial and transverse positioners for relatively positioning the cutting blade and workpiece along respective radial and transverse directions. The controller cooperates with a fast transverse positioner for positioning the cutting blade in predetermined varying transverse positions during a revolution of the workpiece.

  8. Form and performance: body shape and prey-capture success in four drift-feeding minnows.

    PubMed

    Rincón, Pedro A; Bastir, Markus; Grossman, Gary D

    2007-05-01

    Identifying links between morphology and performance for ecologically relevant tasks will help elucidate the relationships between organismal design and fitness. We conducted a laboratory study to quantify the relationship between variation in body shape and prey-capture success in four drift-feeding minnow species. We offered drifting prey to individual fish in a test flume, counted successful strikes to measure prey-capture success and recorded the position (X, Y coordinates) of ten landmarks on each fish's outline to delineate the specimen's form. We then quantified shape variation among species and related it to capture performance through thin-plate spline analysis. Body shape varied significantly among species and with specimen size and was the major determinant of capture success, explaining 45-47% of its variability. Prey-capture success at differing velocities differed among species, but once the effects of shape and size were accounted for, those differences were no longer significant. Allometric shape changes appeared responsible for most of the ontogenetic variation in capture performance, although other size-related, non-shape factors also seemed relevant. Fishes with deeper, shorter bodies, more caudally placed median fins and larger, more upward-pointing mouths exhibited greater capture success than more fusiform fish, suggesting that streamlining, which is energetically advantageous for sustained swimming, entails a cost in terms of prey-capture ability. Our findings demonstrate a strong connection between organismal shape and performance and provide empirical evidence of the cost of morphological specialization for fishes in the drift-feeding functional guild.

  9. Near-net-shape manufacturing: Spray-formed metal matrix composites and tooling

    NASA Technical Reports Server (NTRS)

    Mchugh, Kevin M.

    1994-01-01

    Spray forming is a materials processing technology in which a bulk liquid metal is converted to a spray of fine droplets and deposited onto a substrate or pattern to form a near-net-shape solid. The technology offers unique opportunities for simplifying materials processing without sacrificing, and oftentimes substantially improving, product quality. Spray forming can be performed with a wide range of metals and nonmetals, and offers property improvements resulting from rapid solidification (e.g. refined microstructures, extended solid solubilities and reduced segregation). Economic benefits result from process simplification and the elimination of unit operations. The Idaho National Engineering Laboratory is developing a unique spray-forming method, the Controlled Aspiration Process (CAP), to produce near-net-shape solids and coatings of metals, polymers, and composite materials. Results from two spray-accompanying technical and economic benefits. These programs involved spray forming aluminum strip reinforced with SiC particulate, and the production of tooling, such as injection molds and dies, using low-melting-point metals.

  10. Closed-form modelling and design analysis of V- and Z-shaped electrothermal microactuators

    NASA Astrophysics Data System (ADS)

    Zhang, Zhuo; Zhang, Weize; Wu, Qiyang; Yu, Yueqing; Liu, Xinyu; Zhang, Xuping

    2017-01-01

    This paper presents the modelling and design analysis of V- and Z-shaped electrothermal microactuators. First, a comprehensive but concise closed-form multiphysical analytical model is developed to predict the output displacement and force of both V- and Z-shaped electrothermal microactuators operating either in vacuum or in air conditions. The analytical model is verified by finite element analysis and experimental testing. Then, a novel comparison benchmark is proposed for the design and analysis of the V- and Z-shaped microactuators. With the multiphysical model and comparison benchmark, comprehensive performance comparison and analysis of the V- and Z-shaped beams are performed with the aim of providing insight and guidance on selection and design of the two typical types of electrothermal microactuators. Finally, the application of the comparison model into the design analysis is demonstrated using a design example of an electrothermal microactuator, and the detailed investigation is conducted to examine the effects of the material properties and structural parameters on the microactuator outputs.

  11. Hemispheric Differences in Relational Reasoning: Novel Insights Based on an Old Technique

    PubMed Central

    Vendetti, Michael S.; Johnson, Elizabeth L.; Lemos, Connor J.; Bunge, Silvia A.

    2015-01-01

    Relational reasoning, or the ability to integrate multiple mental relations to arrive at a logical conclusion, is a critical component of higher cognition. A bilateral brain network involving lateral prefrontal and parietal cortices has been consistently implicated in relational reasoning. Some data suggest a preferential role for the left hemisphere in this form of reasoning, whereas others suggest that the two hemispheres make important contributions. To test for a hemispheric asymmetry in relational reasoning, we made use of an old technique known as visual half-field stimulus presentation to manipulate whether stimuli were presented briefly to one hemisphere or the other. Across two experiments, 54 neurologically healthy young adults performed a visuospatial transitive inference task. Pairs of colored shapes were presented rapidly in either the left or right visual hemifield as participants maintained central fixation, thereby isolating initial encoding to the contralateral hemisphere. We observed a left-hemisphere advantage for encoding a series of ordered visuospatial relations, but both hemispheres contributed equally to task performance when the relations were presented out of order. To our knowledge, this is the first study to reveal hemispheric differences in relational encoding in the intact brain. We discuss these findings in the context of a rich literature on hemispheric asymmetries in cognition. PMID:25709577

  12. Hemispheric differences in relational reasoning: novel insights based on an old technique.

    PubMed

    Vendetti, Michael S; Johnson, Elizabeth L; Lemos, Connor J; Bunge, Silvia A

    2015-01-01

    Relational reasoning, or the ability to integrate multiple mental relations to arrive at a logical conclusion, is a critical component of higher cognition. A bilateral brain network involving lateral prefrontal and parietal cortices has been consistently implicated in relational reasoning. Some data suggest a preferential role for the left hemisphere in this form of reasoning, whereas others suggest that the two hemispheres make important contributions. To test for a hemispheric asymmetry in relational reasoning, we made use of an old technique known as visual half-field stimulus presentation to manipulate whether stimuli were presented briefly to one hemisphere or the other. Across two experiments, 54 neurologically healthy young adults performed a visuospatial transitive inference task. Pairs of colored shapes were presented rapidly in either the left or right visual hemifield as participants maintained central fixation, thereby isolating initial encoding to the contralateral hemisphere. We observed a left-hemisphere advantage for encoding a series of ordered visuospatial relations, but both hemispheres contributed equally to task performance when the relations were presented out of order. To our knowledge, this is the first study to reveal hemispheric differences in relational encoding in the intact brain. We discuss these findings in the context of a rich literature on hemispheric asymmetries in cognition.

  13. Hull-form optimization of a container ship based on bell-shaped modification function

    NASA Astrophysics Data System (ADS)

    Choi, Hee Jong

    2015-09-01

    In the present study, a hydrodynamic hull-form optimization algorithm for a container ship was presented in terms of the minimum wave-making resistance. Bell-shaped modification functions were developed to modify the original hull-form and a sequential quadratic programming algorithm was used as an optimizer. The wave-making resistance as an objective function was obtained by the Rankine source panel method in which non-linear free surface conditions and the trim and sinkage of the ship were fully taken into account. Numerical computation was performed to investigate the validity and effectiveness of the proposed hull-form modification algorithm for the container carrier. The computational results were validated by comparing them with the experimental data.

  14. Neptune's Southern Hemisphere

    NASA Technical Reports Server (NTRS)

    1989-01-01

    This photograph of Neptune's southern hemisphere was taken by the narrow-angle camera on NASA's Voyager 2 when the spacecraft was 4.2 million km (2.6 million miles) from the planet. The smallest features that can be seen are 38 km (24 miles) across. The almond-shaped structure at the left is a large cloud system that has been seen for several weeks. Internal details in the feature have become increasingly apparent as Voyager 2 has approached. Systems with similar shapes in Jupiter's atmosphere rotate about their centers, rolling in the local winds that increase toward the south. However, the wispy nature of the white central clouds in this Neptunian feature make confirmation of the system's rotation difficult. The Voyager Mission is conducted by JPL for NASA's Office of Space Science and Applications.

  15. Amphiphilic crescent-moon-shaped microparticles formed by selective adsorption of colloids.

    PubMed

    Kim, Shin-Hyun; Abbaspourrad, Alireza; Weitz, David A

    2011-04-13

    We use a microfluidic device to prepare monodisperse amphiphilic particles in the shape of a crescent-moon and use these particles to stabilize oil droplets in water. The microfluidic device is comprised of a tapered capillary in a theta (θ) shape that injects two oil phases into water in a single receiving capillary. One oil is a fluorocarbon, while the second is a photocurable monomer, which partially wets the first oil drop; silica colloids in the monomer migrate and adsorb to the interface with water but do not protrude into the oil interface. Upon UV-induced polymerization, solid particles with the shape of a crescent moon are formed; removal of fluorocarbon oil yields amphiphilic particles due to the selective adsorption of silica colloids. The resultant amphiphilic microparticles can be used to stabilize oil drops in a mixture of water and ethanol; if they are packed to sufficient surface density on the interface of the oil drop, they become immobilized, preventing direct contact between neighboring drops, thereby providing the stability.

  16. Shape and optical properties of aerosols formed by photolysis of acetylene, ethylene, and hydrogen cyanide

    NASA Astrophysics Data System (ADS)

    Bar-Nun, A.; Kleinfeld, I.; Ganor, E.

    1988-07-01

    The shapes and sizes of photochemically produced aerosol particles of polyacetylene, polyethylene, and polyhydrogen cyanide were studied experimentally. All of the single particles were found to be perfectly spherical and semiliquid. However, they aggregate readily, with a sticking coefficient near unity, to form nonspherical particles, which could give rise to the observed polarization from Titan's and Jupiter's upper haze layers. The absorbance of polyacetylene was remeasured and corrected, and it is now much closer to that of polyethylene. The measured real and imaginary indices of refraction of the two materials make them both suitable material for Titan's and Jupiter's upper haze layers. However, the larger abundance and higher rate of polymerization of acetylene would make it the dominant aerosol-forming material in both atmospheres.

  17. Shape and optical properties of aerosols formed by photolysis of acetylene, ethylene, and hydrogen cyanide

    SciTech Connect

    Bar-Nun, A.; Kleinfeld, I.; Ganor, E.

    1988-07-20

    The shapes and sizes of photochemically produced aerosol particles of polyacetylene, polyethylene, and polyhydrogen cyanide were studied experimentally. All of the single particles were found to be perfectly spherical and semiliquid. However, they aggregate readily, with a sticking coefficient near unity, to form nonspherical particles, which could give rise to the observed polarization from Titan's and Jupiter's upper haze layers. The absorbance of polyacetylene was remeasured and corrected, and it is now much closer to that of polyethylene. The measured real and imaginary indices of refraction of the two materials make them both suitable material for Titan's and Jupiter's upper haze layers. However, the larger abundance and higher rate of polymerization of acetylene would make it the dominant aerosol-forming material in both atmospheres. copyright American Geophysical Union 1988

  18. Net-Shape Forming and Mechanical Properties of MIM418 Turbine Wheel

    NASA Astrophysics Data System (ADS)

    Zhang, Lin; Chen, Xiaowei; Li, Dan; Xuanhui, Qu; Mingli, Qin; Li, Zhou

    2016-09-01

    Near-net shape forming of the turbine wheel with a hollow internal structure was realized by adopting the die with side core-pulling mechanism. MIM418 turbine wheel with relative density above 99.5% is obtained by the combination of vacuum sintering and hot isostatic pressing. A high volume fraction (57%) of near cuboidal γ' phase with average particle size of 0.52 μm is formed in γ matrix. Small amount of discrete carbides with size of 0.2-0.4 μm is distributed uniformly on grain boundaries and within grains. The tensile strength, yield strength, and ductility of MIM418 superalloy reach 1425 MPa, 1004 MPa, and 19.4%, respectively, which are much higher than that of the cast K418 superalloy.

  19. Helical arrays of U-shaped ATP synthase dimers form tubular cristae in ciliate mitochondria

    PubMed Central

    Mühleip, Alexander W.; Joos, Friederike; Wigge, Christoph; Frangakis, Achilleas S.; Kühlbrandt, Werner; Davies, Karen M.

    2016-01-01

    F1Fo-ATP synthases are universal energy-converting membrane protein complexes that synthesize ATP from ADP and inorganic phosphate. In mitochondria of yeast and mammals, the ATP synthase forms V-shaped dimers, which assemble into rows along the highly curved ridges of lamellar cristae. Using electron cryotomography and subtomogram averaging, we have determined the in situ structure and organization of the mitochondrial ATP synthase dimer of the ciliate Paramecium tetraurelia. The ATP synthase forms U-shaped dimers with parallel monomers. Each complex has a prominent intracrista domain, which links the c-ring of one monomer to the peripheral stalk of the other. Close interaction of intracrista domains in adjacent dimers results in the formation of helical ATP synthase dimer arrays, which differ from the loose dimer rows in all other organisms observed so far. The parameters of the helical arrays match those of the cristae tubes, suggesting the unique features of the P. tetraurelia ATP synthase are directly responsible for generating the helical tubular cristae. We conclude that despite major structural differences between ATP synthase dimers of ciliates and other eukaryotes, the formation of ATP synthase dimer rows is a universal feature of mitochondria and a fundamental determinant of cristae morphology. PMID:27402755

  20. Split-brain, the right hemisphere, and art: fact and fiction.

    PubMed

    Zaidel, Dahlia W

    2013-01-01

    The research studies of complete commissurotomy patients (split-brain) in Roger W. Sperry's psychobiology laboratory at Caltech, Pasadena, galvanized the scientific and intellectual world in the 1960s and 1970s. The findings had an important and enduring impact on brain research in countless areas. Interest in hemispheric specialization in particular was sparked by these studies and paved the way for countless discoveries. Right hemisphere specialization for visuospatial functions and facial processing was confirmed with these patients. The further unraveling of right-hemisphere cognition, the "mute" hemisphere, was a major goal in Sperry's laboratory, and much factual knowledge was learned that was not known previously. However, the linking of art and creativity with the right hemisphere was a nonempirically based inference made not by Sperry's lab but rather by others wishing to "assign" functional hemisphericity. The general assumption was that "art" is anchored in spatial cognition, that it is a nonverbal activity requiring imagery and thus must be controlled by the right, nonlanguage hemisphere. To this day, robust evidence that the right specializes in art expression or art perception is yet to be shown, if for no other reason than that art is not a single, unitary form of expression or cognition. The conjectured right hemisphere-art link turned into a popular story that filtered back into science, shaped future research of brain and art, and overlooked other avenues for insights. This chapter traces and explores this background.

  1. Hemispheric asymmetries in the perceptual representations of words.

    PubMed

    Lincoln, Amy E; Long, Debra L; Swick, Diane; Larsen, Jary; Baynes, Kathleen

    2008-01-10

    The representation of words in sentences can involve the activation and integration of perceptual information. For example, readers who are asked to view pictures of objects relating to a word in a sentence are influenced by perceptual information in the sentence context-readers are faster to respond to a picture of a whole apple after reading, "There is an apple in the bag," than after reading, "There is an apple in the salad." The purpose of this study was to examine how the two cerebral hemispheres use perceptual information about words as a function of sentence context. Patients who had damage to the left or right hemisphere and age-matched control participants read sentences that described, but did not entail, the shape or state of an object. They then made recognition judgments to pictures that either matched or mismatched the perceptual form implied by the sentence. Responses and latencies were examined for a match effect -- faster and more accurate responses to pictures in the match than mismatch condition -- controlling for comprehension ability and lesion size. When comprehension ability and lesion size are properly controlled, left-hemisphere-damaged patients and control participants exhibited the expected match effect, whereas right-hemisphere-damaged participants showed no effect of match condition. These results are consistent with research implicating the right hemisphere in the representation of contextually relevant perceptual information.

  2. A Skeleton-Based 3D Shape Reconstruction of Free-Form Objects with Stereo Vision

    NASA Astrophysics Data System (ADS)

    Saini, Deepika; Kumar, Sanjeev

    2015-12-01

    In this paper, an efficient approach is proposed for recovering the 3D shape of a free-form object from its arbitrary pair of stereo images. In particular, the reconstruction problem is treated as the reconstruction of the skeleton and the external boundary of the object. The reconstructed skeleton is termed as the line-like representation or curve-skeleton of the 3D object. The proposed solution for object reconstruction is based on this evolved curve-skeleton. It is used as a seed for recovering shape of the 3D object, and the extracted boundary is used for terminating the growing process of the object. NURBS-skeleton is used to extract the skeleton of both views. Affine invariant property of the convex hulls is used to establish the correspondence between the skeletons and boundaries in the stereo images. In the growing process, a distance field is defined for each skeleton point as the smallest distance from that point to the boundary of the object. A sphere centered at a skeleton point of radius equal to the minimum distance to the boundary is tangential to the boundary. Filling in the spheres centered at each skeleton point reconstructs the object. Several results are presented in order to check the applicability and validity of the proposed algorithm.

  3. A MEMS diamond hemispherical resonator

    NASA Astrophysics Data System (ADS)

    Bernstein, J. J.; Bancu, M. G.; Cook, E. H.; Chaparala, M. V.; Teynor, W. A.; Weinberg, M. S.

    2013-12-01

    In this paper we report the fabrication of hemispherical polycrystalline diamond resonators fabricated on a novel high-temperature glass substrate. The hemispherical resonator gyroscope is one of the most accurate and rugged of the mechanical gyroscopes, and can be operated in either rate or whole-angle mode due to its high degree of symmetry. A fabrication sequence for creating extremely symmetric 3D MEMS hemispheres is presented. Mode shapes and frequencies obtained with a laser vibrometer are shown, as well as curves of Q versus pressure, and the dependence of frequency on anchor size. Fundamental mode frequency matching to <0.1% in as-fabricated devices has been achieved, which is essential to gyroscope operation in whole-angle mode.

  4. 3D shape measurement of optical free-form surface based on fringe projection

    NASA Astrophysics Data System (ADS)

    Li, Shaohui; Liu, Shugui; Zhang, Hongwei

    2011-05-01

    Present a novel method of 3D shape measurement of optical free-from surface based on fringe projection. A virtual reference surface is proposed which can be used to improve the detection efficiency and realize the automation of measuring process. Sinusoidal fringe patterns are projected to the high reflected surface of the measured object. The deflection fringe patterns that modulated by the object surface are captured by the CCD camera. The slope information can be obtained by analyzing the relationship between the phase deflectometry and the slope of the object surface. The wave-front reconstruction method is used to reconstruct the surface. With the application of fringe projection technology the accuracy of optical free-form surfaces measurement could reach the level of tens of micrometer or even micrometer.

  5. General associative learning shapes the plasticity of the visual word form area.

    PubMed

    Song, Yiying; Bu, Yong; Liu, Jia

    2010-03-31

    Earlier studies identify a region in the left fusiform gyrus that responds selectively to visual words, termed the visual word form area (VWFA). Converging evidence suggests that the VWFA is wired up largely by language experience. Here we asked whether general associative experience without explicit language learning accounts for the selectivity of the VWFA. Specifically, we trained individuals to associate novel stimuli with objects. We found that the blood oxygen level-dependent response of the VWFA to the trained stimuli was significantly higher than that of visually similar but untrained stimuli. No learning effects were found in the face-selective and object-selective regions. Our study illuminates that the plasticity of the VWFA can be shaped by associative learning without language experience.

  6. MACHINING ELIMINATION THROUGH APPLICATION OF THREAD FORMING FASTENERS IN NET SHAPED CAST HOLES

    SciTech Connect

    Cleaver, Ryan J; Cleaver, Todd H; Talbott, Richard

    2012-05-02

    The ultimate objective of this work was to eliminate approximately 30% of the machining performed in typical automotive engine and transmission plants by using thread forming fasteners in as-cast holes of aluminum and magnesium cast components. The primary issues at the source of engineers reluctance to implementing thread forming fasteners in lightweight castings are: * Little proof of consistency of clamp load vs. input torque in either aluminum or magnesium castings. * No known data to understand the effect on consistency of clamp load as casting dies wear. The clamp load consistency concern is founded in the fact that a portion of the input torque used to create clamp load is also used to create threads. The torque used for thread forming may not be consistent due to variations in casting material, hole size and shape due to tooling wear and process variation (thermal and mechanical). There is little data available to understand the magnitude of this concern or to form the basis of potential solutions if the range of clamp load variation is very high (> +/- 30%). The range of variation that can be expected in as-cast hole size and shape over the full life cycle of a high pressure die casting die was established in previous work completed by Pacific Northwest National Laboratory, (PNNL). This established range of variation was captured in a set of 12 cast bosses by designing core pins at the size and draft angles identified in the sited previous work. The cast bosses were cut into nuts that could be used in the Ford Fastener Laboratory test-cell to measure clamp load when a thread forming fastener was driven into a cast nut. There were two sets of experiments run. First, a series of cast aluminum nuts were made reflecting the range of shape and size variations to be expected over the life cycle of a die casting die. Taptite thread forming fasteners, (a widely used thread forming fastener suitable for aluminum applications), were driven into the various cored, as

  7. Near net shape forming processes for chemically prepared zinc oxide varistors.

    SciTech Connect

    Lockwood, Steven John; Voigt, James A.; Tuttle, Bruce Andrew; Bell, Nelson Simmons

    2005-01-01

    Chemically prepared zinc oxide powders are fabricated for the production of high aspect ratio varistor components. Colloidal processing in water was performed to reduce agglomerates to primary particles, form a high solids loading slurry, and prevent dopant migration. The milled and dispersed powder exhibited a viscoelastic to elastic behavioral transition at a volume loading of 43-46%. The origin of this transition was studied using acoustic spectroscopy, zeta potential measurements and oscillatory rheology. The phenomenon occurs due to a volume fraction solids dependent reduction in the zeta potential of the solid phase. It is postulated to result from divalent ion binding within the polyelectrolyte dispersant chain, and was mitigated using a polyethylene glycol plasticizing additive. Chemically prepared zinc oxide powders were processed for the production of high aspect ratio varistor components. Near net shape casting methods including slip casting and agarose gelcasting were evaluated for effectiveness in achieving a uniform green microstructure achieving density values near the theoretical maximum during sintering. The structure of the green parts was examined by mercury porisimetry. Agarose gelcasting produced green parts with low solids loading values and did not achieve high fired density. Isopressing the agarose cast parts after drying raised the fired density to greater than 95%, but the parts exhibited catastrophic shorting during electrical testing. Slip casting produced high green density parts, which exhibited high fired density values. The electrical characteristics of slip cast parts are comparable with dry pressed powder compacts. Alternative methods for near net shape forming of ceramic dispersions were investigated for use with the chemically prepared ZnO material. Recommendations for further investigation to achieve a viable production process are presented.

  8. Surface form memory by indentation-planarization training of nickel titanium shape memory alloys

    NASA Astrophysics Data System (ADS)

    Fei, Xueling

    Shape memory alloys respond to deformation by indentation with strong two-way cyclic displacements on heating and cooling. Shallow indents can vanish on heating, and deeper indents will change depth when thermally cycled. In the present work, following indentation by an added step of surface planarization can furthermore produce what has been termed "Surface Form Memory" or SFM. The term SFM describes an effect that causes one surface form to reversibly transform to another, under thermal excitation. The term surface form is meant to distinguish between say, flat and "bumpy" surfaces, on a scale much larger than the intrinsic surface roughness. Surface protrusions, or 'exdents' may reach an amplitude near 20% of the initial indent depth, and may be created on nano to macroscopic size scales. The surface form memory effect may have special applications into novel optical, microelectromechanical, and tribological systems. Surface deformation of a NiTi shape memory alloy (SMA) was accomplished using spherical, cylindrical, pyramidal, and flat punch indenters. Single indents and indent arrays have been made. The amplitude of SFM after planarization was found to be related to the size of the subsurface deformation zone and can be maximized by thermal cycling, multiple indentations, by changing indent depth and spacing, and by varying indentation temperature parameters. The spatial extent of the subsurface deformation zone was studied by both experimental methods and finite element modeling. Methods such as successive front and back thinning probed the size of the deformation zone directly, while finite element modeling provided stress-strain information supporting the conclusion that the deformation zone responsible for the two-way effect was a slip zone that had plastic strains larger than 7%. NiTi SFM, when studied in constrained recovery experiments, showed an energy density up to 10 MJ/m3, which is about the same as that of a conventional NiTi actuator. This proves

  9. Fluctuations and Shape of Cooperative Rearranging Regions in Glass-Forming Liquids

    NASA Astrophysics Data System (ADS)

    Biroli, Giulio; Cammarota, Chiara

    2017-01-01

    We develop a theory of amorphous interfaces in glass-forming liquids. We show that the statistical properties of these surfaces, which separate regions characterized by different amorphous arrangements of particles, coincide with the ones of domain walls in the random field Ising model. A major consequence of our results is that supercooled liquids are characterized by two different static lengths: the point-to-set ξPS , which is a measure of the spatial extent of cooperative rearranging regions, and the wandering length ξ⊥, which is related to the fluctuations of their shape. We find that ξ⊥ grows when approaching the glass transition but slower than ξPS. The wandering length increases as sc-1 /2, where sc is the configurational entropy. Our results strengthen the relationship with the random field Ising model found in recent works. They are in agreement with previous numerical studies of amorphous interfaces and provide a theoretical framework for explaining numerical and experimental findings on pinned particle systems and static lengths in glass-forming liquids.

  10. The Shape of Things: The Origin of Young Children's Knowledge of the Names and Properties of Geometric Forms

    PubMed Central

    Verdine, Brian N.; Lucca, Kelsey R.; Golinkoff, Roberta Michnick; Hirsh-Pasek, Kathy; Newcombe, Nora S.

    2015-01-01

    How do toddlers learn the names of geometric forms? Past work suggests that preschoolers have fragmentary knowledge and that defining properties are not understood until well into elementary school. The current study investigates when children first begin to understand shape names and how they apply those labels to unusual instances. We tested 25- and 30-month-old children's (N = 30 each) understanding of names for canonical shapes (commonly-encountered instances, e.g., equilateral triangles), non-canonical shapes (more irregular instances, e.g., scalene triangles), and embedded shapes (shapes within a larger picture, e.g., triangular slices of pizza). At 25 months, children know very few names, including those for canonical shapes. By 30 months, however, children have acquired more shape names, and are beginning to apply them to some of the less typical instances of the shapes. Possible mechanisms driving this initial development of shape knowledge and implications of that development for school readiness are explored. PMID:27019647

  11. Dendritic Domains with Hexagonal Symmetry Formed by X-Shaped Bolapolyphiles in Lipid Membranes

    PubMed Central

    Werner, Stefan; Ebert, Helgard; Lechner, Bob-Dan; Lange, Frank; Achilles, Anja; Bärenwald, Ruth; Poppe, Silvio; Blume, Alfred; Saalwächter, Kay; Tschierske, Carsten; Bacia, Kirsten

    2015-01-01

    A novel class of bolapolyphile (BP) molecules are shown to integrate into phospholipid bilayers and self-assemble into unique sixfold symmetric domains of snowflake-like dendritic shapes. The BPs comprise three philicities: a lipophilic, rigid, π–π stacking core; two flexible lipophilic side chains; and two hydrophilic, hydrogen-bonding head groups. Confocal microscopy, differential scanning calorimetry, XRD, and solid-state NMR spectroscopy confirm BP-rich domains with transmembrane-oriented BPs and three to four lipid molecules per BP. Both species remain well organized even above the main 1,2-dipalmitoyl-sn-glycero-3-phosphocholine transition. The BP molecules only dissolve in the fluid membrane above 70 °C. Structural variations of the BP demonstrate that head-group hydrogen bonding is a prerequisite for domain formation. Independent of the head group, the BPs reduce membrane corrugation. In conclusion, the BPs form nanofilaments by π stacking of aromatic cores, which reduce membrane corrugation and possibly fuse into a hexagonal network in the dendritic domains. PMID:25940233

  12. Form Perception of Partly Occluded Shapes in 4-Month-Old Infants

    ERIC Educational Resources Information Center

    de Wit, Tessa C. J.; Vrins, Sven; Dejonckheere, Peter J. N.; van Lier, Rob

    2008-01-01

    Two habituation experiments were conducted to investigate how 4-month-old infants perceive partly occluded shapes. In the first experiment, we presented a simple, partly occluded shape to the infants until habituation was reached. Then we showed either a probable completion (one that would be predicted on the basis of both local and global cues)…

  13. A unified free-form representation applied to the shape optimization of the hohlraum with octahedral 6 laser entrance holes

    SciTech Connect

    Jiang, Shaoen; Ding, Yongkun; Huang, Yunbao E-mail: scmyking-2008@163.com; Li, Haiyan; Jing, Longfei E-mail: scmyking-2008@163.com; Huang, Tianxuan

    2016-01-15

    The hohlraum is very crucial for indirect laser driven Inertial Confinement Fusion. Usually, its shape is designed as sphere, cylinder, or rugby with some kind of fixed functions, such as ellipse or parabola. Recently, a spherical hohlraum with octahedral 6 laser entrance holes (LEHs) has been presented with high flux symmetry [Lan et al., Phys. Plasmas 21, 010704 (2014); 21, 052704 (2014)]. However, there is only one shape parameter, i.e., the hohlraum to capsule radius ratio, being optimized. In this paper, we build the hohlraum with octahedral 6LEHs with a unified free-form representation, in which, by varying additional shape parameters: (1) available hohlraum shapes can be uniformly and accurately represented, (2) it can be used to understand why the spherical hohlraum has higher flux symmetry, (3) it allows us to obtain a feasible shape design field satisfying flux symmetry constraints, and (4) a synthetically optimized hohlraum can be obtained with a tradeoff of flux symmetry and other hohlraum performance. Finally, the hohlraum with octahedral 6LEHs is modeled, analyzed, and then optimized based on the unified free-form representation. The results show that a feasible shape design field with flux asymmetry no more than 1% can be obtained, and over the feasible design field, the spherical hohlraum is validated to have the highest flux symmetry, and a synthetically optimal hohlraum can be found with closing flux symmetry but larger volume between laser spots and centrally located capsule.

  14. Hemispheric sunspot unit area: comparison with hemispheric sunspot number and sunspot area

    SciTech Connect

    Li, K. J.; Xiang, N. B.; Qu, Z. N.; Xie, J. L.

    2014-03-01

    The monthly mean northern and southern hemispheric sunspot numbers (SNs) and sunspot areas (SAs) in the time interval of 1945 January to 2012 December are utilized to construct the monthly northern and southern hemispheric sunspot unit areas (SUAs), which are defined as the ratio of hemispheric SA to SN. Hemispheric SUAs are usually found to rise at the beginning and to fall at the ending time of a solar cycle more rapidly, forming a more irregular cycle profile than hemispheric SNs and SAs, although it also presents Schwabe-cycle-like hemispheric SNs and SAs. Sunspot activity (SN, SA, and SUA) is found asynchronously and is asymmetrically distributed in the northern and southern hemispheres, and hemispheric SNs, SAs, and SUAs are not in phase in the two hemispheres. The similarity of hemispheric SNs and SAs is found to be much more obvious than that of hemispheric SUAs and SNs (or SAs), and also for their north-south asymmetry. A notable feature is found for the behavior of the SUA around the minimum time of cycle 24: the SUA rapidly decreases from the cycle maximum value to the cycle minimum value of sunspot cycles 19-24 within just 22 months.

  15. Method for estimating closed-form solutions of the light diffusion equation for turbid media of any boundary shape

    PubMed Central

    Alqasemi, Umar; Salehi, Hassan S.; Zhu, Quing

    2016-01-01

    This paper reports a method of estimating an approximate closed-form solution to the light diffusion equation for any type of geometry involving Dirichlet’s boundary condition with known source location. It is based on estimating the optimum locations of multiple imaginary point sources to cancel the fluence at the extrapolated boundary by constrained optimization using a genetic algorithm. The mathematical derivation of the problem to approach the optimum solution for the direct-current type of diffuse optical systems is described in detail. Our method is first applied to slab geometry and compared with a truncated series solution. After that, it is applied to hemispherical geometry and compared with Monte Carlo simulation results. The method provides a fast and sufficiently accurate fluence distribution for optical reconstruction. PMID:26831771

  16. Study of dynamical formation and shape of microlenses formed by the reflow method

    NASA Astrophysics Data System (ADS)

    Audran, S.; Faure, B.; Mortini, B.; Aumont, C.; Tiron, R.; Zinck, C.; Sanchez, Y.; Fellous, C.; Regolini, J.; Reynard, J. P.; Schlatter, G.; Hadziioannou, G.

    2006-03-01

    Microlenses arrays are commonly used in CMOS images sensors to focus the incident light onto the photosensitive area of the pixel. These microlenses are fabricated using a thermal reflow method. Currently, due to the fast evolution of CMOS Imager technology, the understanding of the mechanisms involved in microlens formation becomes essential to better control what occurs during the process. We have seen in a previous study that the complexity of the reflow method comes from the competition between two phenomena occurring during the melt bake step: on one hand the surface tension tends to push the resist patterns into a spherical shape, on the other hand the resist crosslinking reaction drastically increases the resist viscosity hindering the microlens formation. In this paper the influence of resist crosslinking, resist volume and resist/substrate interface on the final shape of the microlens has been investigated. It appears that the contact angle between microlens and substrate varies depending on substrate wettability but is the same whatever the resist volume for a given substrate/resist combination. The microlens shape depends also significantly on bake temperature and crosslinking kinetics. In fact the right tuning of process conditions seems to be the key parameter in the control of the final microlens shape because it enables to adjust the kinetics of each mechanism and thus favour the microlens formation with regards to resist crosslinking.

  17. Evaluation of tungsten shaped-charge liners spray-formed using the low-pressure plasma spray process

    SciTech Connect

    Buchanan, E.R.; Sickinger, A.

    1994-12-31

    This paper documents the results of a DARPA Phase 1 SBIR program which was awarded following a solicitation to develop new technologies for the forming of refractory metal shaped-charge liners. Holtgren had proposed to manufacture liners by spraying refractory metal powder onto a rapidly-rotating mandrel inside the chamber of a low-pressure plasma spray system. A total of nine tungsten shaped-charge liners were sprayed during the course of the program. Metallographic evaluation of the liners revealed that the as-sprayed microstructure was dense, averaging 98.5% density. The grain structure is equiaxed and fine, averaging five microns in diameter. The sprayed shapes were then processed to the final liner configuration by cylindrical grinding. The liners were ductile enough to withstand the strains of grinding and normal handling.

  18. ``Nanoarmoured'' droplets of different shapes formed by interfacial self-assembly and crosslinking of metal nanoparticles

    NASA Astrophysics Data System (ADS)

    Kowalczyk, Bartlomiej; Lagzi, István; Grzybowski, Bartosz A.

    2010-11-01

    Films comprising metal nanoparticles are assembled on the surfaces of liquid droplets of different shapes and macroscopic dimensions. These films are reinforced by dithiol crosslinks and are mechanically rugged yet permeable to the diffusion of small molecules.Films comprising metal nanoparticles are assembled on the surfaces of liquid droplets of different shapes and macroscopic dimensions. These films are reinforced by dithiol crosslinks and are mechanically rugged yet permeable to the diffusion of small molecules. Electronic supplementary information (ESI) available: Movie 1 illustrating water uptake experiments (Fig. 2d-f). Movie 2 illustrating thawing and disintegration of a droplet infused with bromothymol blue. Experimental details. See DOI: 10.1039/c0nr00381f

  19. Simulation of the shape of chaperonins using the small-angle x-ray scattering curves and torus form factor

    SciTech Connect

    Amarantov, S. V.; Naletova, I. N.; Kurochkina, L. P.

    2011-08-15

    The inverse scattering problem has been solved for protein complexes whose surfaces can be described by a set of the simplest doubly connected surfaces in the uniform approximation (a scattering potential inside the molecule is a constant). Solutions of two proteins-well-known GroEL bacterial chaperonin and poor-studied bacteriophage chaperonin, which is a product of 146 gene (gp146)-were taken for the experiment. The shapes of protein complexes have been efficiently reconstructed from the experimental scattering curves. The shell method, the method of the rotation of amino acid sequences with the use of the form factor of an amino acid, and the method of seeking the model parameters of a protein complex with the preliminarily obtained form factor of the model have been used to reconstruct the shape of these particles.

  20. Story Telling or Storied Telling? Media's Pedagogical Ability to Shape Narrative as a Form of "Knowing"

    ERIC Educational Resources Information Center

    Blevins, Dean G.

    2007-01-01

    Storytellers know that stories are "formed" in their telling. Stories, whether oral or written, personal or mass communicated, ultimately express the boundaries of their medium (their "embodiment" through mediated forms). Religious Educators must always address the medium as well as the message in any theory of narrative accounting. Media often…

  1. Proton beam shaped by "particle lens" formed by laser-driven hot electrons

    NASA Astrophysics Data System (ADS)

    Zhai, S. H.; Shen, B. F.; Wang, W. P.; Zhang, H.; He, S. K.; Lu, F.; Zhang, F. Q.; Deng, Z. G.; Dong, K. G.; Wang, S. Y.; Zhou, K. N.; Xie, N.; Wang, X. D.; Zhang, L. G.; Huang, S.; Liu, H. J.; Zhao, Z. Q.; Gu, Y. Q.; Zhang, B. H.; Xu, Z. Z.

    2016-05-01

    Two-dimensional tailoring of a proton beam is realized by a "particle lens" in our experiment. A large quantity of electrons, generated by an intense femtosecond laser irradiating a polymer target, produces an electric field strong enough to change the trajectory and distribution of energetic protons flying through the electron area. The experiment shows that a strip pattern of the proton beam appears when hot electrons initially converge inside the plastic plate. Then the shape of the proton beam changes to a "fountain-like" pattern when these hot electrons diffuse after propagating a distance.

  2. Free form fabrication using the laser engineered net shaping (LENS{trademark}) process

    SciTech Connect

    Keicher, D.M.; Romero, J.A.; Atwood, C.L.; Griffith, M.L.; Jeantette, F.P.; Harwell, L.D.; Greene, D.L.; Smugeresky, J.E.

    1996-12-31

    Sandia National Laboratories is developing a technology called Laser Engineered Net Shaping{trademark} (LENS{trademark}). This process allows complex 3-dimensional solid metallic objects to be directly fabricated for a CAD solid model. Experiments performed demonstrate that complex alloys such as Inconel{trademark} 625 and ANSI stainless steel alloy 316 can be used in the LENS{trademark} process to produce solid metallic-shapes. In fact, the fabricated structures exhibit grain growth across the deposition layer boundaries. Mechanical testing data of deposited 316 stainless steel material indicates that the deposited material strength and elongation are greater than that reported for annealed 316 stainless steel. Electron microprobe analysis of the deposited Inconel{trademark} 625 material shows no compositional degradation of the 625 alloy and that 100% dense structures can be obtained using this technique. High speed imaging used to acquire process data during experimentation shows that the powder particle size range can significantly affect the stability, and subsequently, the performance of the powder deposition process. Finally, dimensional studies suggest that dimensional accuracy to {+-} 0.002 inches (in the horizontal direction) can be maintained.

  3. A non-invasive heuristic approach to shape optimization in forming

    NASA Astrophysics Data System (ADS)

    Landkammer, P.; Steinmann, P.

    2016-02-01

    The aim is to determine—relating to a given forming process—the optimal material (undeformed) configuration of a workpiece when knowing the target spatial (deformed) configuration. Therefore, the nodal positions of a discretized setting based on the finite element method (FEM) are the discrete free parameters of the form finding problem. As a verification, inputting the determined optimal material nodal positions, a subsequent re-computation of the forming process should then result in exactly the target spatial nodal positions. A new, non-invasive iterative algorithm, which is purely based on the nodal data of each iteration, is proposed to determine the discretized optimal material configuration. Specifically, the L^2-smoothed deformation gradient at each discretization node is used to update the discretized material configuration by a transformation of the difference vectors between the currently computed and the target spatial nodal positions. The iterative strategy can be easily coupled in a non-invasive fashion via subroutines with arbitrary external FEM software. Since only the computed positions of the discretization nodes are required for an update step within the form finding algorithm, the procedure does not depend on the specific material modelling and is moreover applicable to arbitrary element types, e. g. solid- or solid-shell-elements. Furthermore the convergence rate for solving the form finding problem is nearly linear. This is demonstrated by examples that are realized by a coupling of Matlab (iterative update procedure) and MSC.Marc (external FEM software). Solving the form finding problem to determine an optimum workpiece design is of great interest especially for metal forming applications.

  4. Hemispherical spondylosclerosis - a polyetiologic syndrome

    SciTech Connect

    Dihlmann, W.

    1981-11-01

    Radiologic examination of 43 patients revealed 47 lesions of a type which we have termed hemispherical spondylosclerosis (HSS). This term describes and includes the following essential and possible radiologic findings of the disease: 1) Hemispherical (or dome - or helmet-shaped ) sclerosis of the vertebra above the intervertebral disk. Thus it is a supradiscal HSS. 2) One or more small erosions of the inferior end plate of the vertebra involved. 3) Periosteal apposition on the anterior border of the vertebra along the length of the sclerosis. 4) New bone formation on the inferior end plate. 5) Anterior vertebral osteophytes. 6) Narrowing of the disk space below the affected vertebra. HSS occurs not only as a sequel of degenerative disk disease, but also in bacterial (tuberculous and non-tuberculous) spondylitis, ankylosing spondylitis, osteoid osteoma, and metastases of neoplasms. The differential diagnosis between inflammatory and non-inflammatory pathogenesis and etiology of HSS is described. The characteristic shape of HSS, its sites of predilection (L4 >> L5 > L3), and the preponderance of female sufferers from this painful condition are due to factors which, as yet, remain unknown.

  5. Excitatory cortical neurons with multipolar shape establish neuronal polarity by forming a tangentially oriented axon in the intermediate zone.

    PubMed

    Hatanaka, Yumiko; Yamauchi, Kenta

    2013-01-01

    The formation of axon-dendrite polarity is crucial for neuron to make the proper information flow within the brain. Although the processes of neuronal polarity formation have been extensively studied using neurons in dissociated culture, the corresponding developmental processes in vivo are still unclear. Here, we illuminate the initial steps of morphological polarization of excitatory cortical neurons in situ, by sparsely labeling their neuroepithelial progenitors using in utero electroporation and then examining their neuronal progeny in brain sections and in slice cultures. Morphological analysis showed that an axon-like long tangential process formed in progeny cells in the intermediate zone (IZ). Time-lapse imaging analysis using slice culture revealed that progeny cells with multipolar shape, after alternately extending and retracting their short processes for several hours, suddenly elongated a long process tangentially. These cells then transformed into a bipolar shape, extending a pia-directed leading process, and migrated radially leaving the tangential process behind, which gave rise to an "L-shaped" axon. Our findings suggest that neuronal polarity in these cells is established de novo from a nonpolarized stage in vivo and indicate that excitatory cortical neurons with multipolar shape in the IZ initiate axon outgrowth before radial migration into the cortical plate.

  6. Tissue engineering with electric fields: investigation of the shape of mammalian cell aggregates formed at interdigitated oppositely castellated electrodes.

    PubMed

    Sebastian, Anil; Venkatesh, Alagarswamy G; Markx, Gerard H

    2007-11-01

    The shape of aggregates of cells formed by positive dielectrophoresis (DEP) at interdigitated oppositely castellated electrodes under different conditions was investigated and compared with calculations of the electric field gradient |nablaE(2)|, and the electric field E, and E(2). The results confirm that at low field strength the cells predominantly accumulate above the tips of the electrodes, but at higher electric field strengths the cells predominantly accumulate in the middle of the aggregate. For a given electrode size, a higher applied voltage significantly increases the aggregate footprint. Higher flow rates distort this pattern, with more cells accumulating at the electrodes that are upstream. Calculation of the electric field strength E, E(2) and the electric field strength gradient |nablaE(2)| in the interdigitated oppositely castellated electrode array shows that, at low flow rates, there is a strong correlation between the aggregate shape and the distribution of the electric field E and E(2), but not so between the aggregate shape and |nablaE(2)|. The results indicate that interparticle forces such as pearlchain formation strongly affect the aggregation process, but that, when positive DEP is used to make the aggregates, the distribution of the electric field E, or better E(2), can be used as a useful guide to the final aggregate shape.

  7. Southern hemisphere observations

    NASA Astrophysics Data System (ADS)

    Orchiston, Wayne

    Because of insurmountable problems associated with absolute dating, the non-literate cultures of the Southern Hemisphere can contribute little to Applied Historical Astronomy, although Maori traditions document a possible supernova dating to the period 1000-1770 AD. In contrast, the abundant nineteenth century solar, planetary, cometary and stellar observational data provided by Southern Hemisphere professional and amateur observatories can serve as an invaluable mine of information for present-day astronomers seeking to incorporate historical data in their investigations.

  8. Hemispherical Laue camera

    DOEpatents

    Li, James C. M.; Chu, Sungnee G.

    1980-01-01

    A hemispherical Laue camera comprises a crystal sample mount for positioning a sample to be analyzed at the center of sphere of a hemispherical, X-radiation sensitive film cassette, a collimator, a stationary or rotating sample mount and a set of standard spherical projection spheres. X-radiation generated from an external source is directed through the collimator to impinge onto the single crystal sample on the stationary mount. The diffracted beam is recorded on the hemispherical X-radiation sensitive film mounted inside the hemispherical film cassette in either transmission or back-reflection geometry. The distances travelled by X-radiation diffracted from the crystal to the hemispherical film are the same for all crystal planes which satisfy Bragg's Law. The recorded diffraction spots or Laue spots on the film thereby preserve both the symmetry information of the crystal structure and the relative intensities which are directly related to the relative structure factors of the crystal orientations. The diffraction pattern on the exposed film is compared with the known diffraction pattern on one of the standard spherical projection spheres for a specific crystal structure to determine the orientation of the crystal sample. By replacing the stationary sample support with a rotating sample mount, the hemispherical Laue camera can be used for crystal structure determination in a manner previously provided in conventional Debye-Scherrer cameras.

  9. Hemispheric contributions to pragmatics.

    PubMed

    Zaidel, E; Kasher, A; Soroker, N; Batori, G; Giora, R; Graves, D

    2000-01-01

    Twenty-seven patients with right-hemisphere damage (RBD) and thirty-one patients with left-hemisphere damage (LBD) received a new pragmatics battery in Hebrew consisting of two parts: (1) comprehension and production of basic speech acts (BSAs), including tests of assertions, questions, requests, and commands, and (2) comprehension of implicatures, including implicatures of quantity, quality, relevance, and manner. Each test had a verbal and a nonverbal version. Patients also received Hebrew versions of the Western Aphasia Battery and of the Right Hemisphere Communication Battery. Both LBD and RBD patients were impaired relative to controls but did not differ from each other in their overall scores on BSAs and on Implicatures when scores were corrected by aphasia and neglect indices. There was a systematic localization of BSAs in the left hemisphere (LH) but not in the right hemisphere (RH). There was poor localization of Implicatures in either hemisphere. In LBD patients, BSAs were associated with language functions measured with the WAB, suggesting the radical possibility that the classic localization of language functions in aphasia is influenced by the localization of the BSAs required by aphasia language tests. Both BSAs and implicatures show greater functional independence from other pragmatic, language and cognitive functions in the RBD than in the LBD patients. Thus, the LH is more likely to contain an unmodular domain-nonspecific set of central cognitive mechanisms for applying means-ends rationality principles to intentional activity.

  10. Methodology development for the sustainability process assessment of sheet metal forming of complex-shaped products

    NASA Astrophysics Data System (ADS)

    Pankratov, D. L.; Kashapova, L. R.

    2015-06-01

    A methodology was developed for automated assessment of the reliability of the process of sheet metal forming process to reduce the defects in complex components manufacture. The article identifies the range of allowable values of the stamp parameters to obtain defect-free punching of spars trucks.

  11. How predation shaped fish: the impact of fin spines on body form evolution across teleosts

    PubMed Central

    Price, S. A.; Friedman, S. T.; Wainwright, P. C.

    2015-01-01

    It is well known that predators can induce morphological changes in some fish: individuals exposed to predation cues increase body depth and the length of spines. We hypothesize that these structures may evolve synergistically, as together, these traits will further enlarge the body dimensions of the fish that gape-limited predators must overcome. We therefore expect that the orientation of the spines will predict which body dimension increases in the presence of predators. Using phylogenetic comparative methods, we tested this prediction on the macroevolutionary scale across 347 teleost families, which display considerable variation in fin spines, body depth and width. Consistent with our predictions, we demonstrate that fin spines on the vertical plane (dorsal and anal fins) are associated with a deeper-bodied optimum. Lineages with spines on the horizontal plane (pectoral fins) are associated with a wider-bodied optimum. Optimal body dimensions across lineages without spines paralleling the body dimension match the allometric expectation. Additionally, lineages with longer spines have deeper and wider body dimensions. This evolutionary relationship between fin spines and body dimensions across teleosts reveals functional synergy between these two traits and a potential macroevolutionary signature of predation on the evolutionary dynamics of body shape. PMID:26559954

  12. Spindle-shaped Microstructures: Potential Models for Planktonic Life Forms on Other Worlds

    NASA Technical Reports Server (NTRS)

    Oehler, Dorothy Z.; Walsh, Maud M.; Sugitani, Kenichiro; House, Christopher H.

    2014-01-01

    Spindle-shaped, organic microstructures ("spindles") are now known from Archean cherts in three localities (Figs. 1-4): The 3 Ga Farrel Quartzite from the Pilbara of Australia [1]; the older, 3.3-3.4 Ga Strelley Pool Formation, also from the Pilbara of Australia [2]; and the 3.4 Ga Kromberg Formation of the Barberton Mountain Land of South Africa [3]. Though the spindles were previously speculated to be pseudofossils or epigenetic organic contaminants, a growing body of data suggests that these structures are bona fide microfossils and further, that they are syngenetic with the Archean cherts in which they occur [1-2, 4-10]. As such, the spindles are among some of the oldest-known organically preserved microfossils on Earth. Moreover, recent delta C-13 study of individual spindles from the Farrel Quartzite (using Secondary Ion Mass Spectrometry [SIMS]) suggests that the spindles may have been planktonic (living in open water), as opposed to benthic (living as bottom dwellers in contact with muds or sediments) [9]. Since most Precambrian microbiotas have been described from benthic, matforming communities, a planktonic lifestyle for the spindles suggests that these structures could represent a segment of the Archean biosphere that is poorly known. Here we synthesize the recent work on the spindles, and we add new observations regarding their geographic distribution, robustness, planktonic habit, and long-lived success. We then discuss their potential evolutionary and astrobiological significance.

  13. Theoretical study on substituent and solvent effects for nanocubes formed with gear-shaped amphiphile molecules.

    PubMed

    Mashiko, T; Hiraoka, S; Nagashima, U; Tachikawa, M

    2017-01-04

    Gear-shaped amphiphile molecules (1) recently synthesized by Hiraoka et al. self-assemble into a hexameric structure, nanocubes (16), in 25% aqueous methanol due to a solvophobic effect. Here we have carried out molecular dynamic simulations to elucidate the stability of these hexameric capsules (16 and 26) in water, 25% aqueous methanol, and methanol. In all solvents, the 16 nanocubes are maintained for all trajectories. On the other hand, 26 was found to collapse for one trajectory in water and seven trajectories in 25% aqueous methanol. In a pure methanol solvent, 26 was found to collapse for all trajectories. The number of collapsed trajectories of 26 increased with the amount of methanol in the solvent. We therefore focused on the structure of the π-π stacking between pyridyl groups and the CH-π interactions between the methyl and pyridyl groups within the nanocube. Our study clearly shows the role played by the methanol solvent molecules in the assembly of the nanocube in terms of the substituent and solvent effects at the molecular level, and that these substituent and solvent effects are important for the self-assembly of the nanocubes.

  14. Reaction-Forming Method for Producing Near Net-Shape Refractory Metal Carbides

    SciTech Connect

    Palmisiano, Marc N.; Jakubenas, Kevin J.; Baranwal, Rita

    2004-07-20

    A method for reaction forming refractory metal carbides. The method involves the fabrication of a glassy carbon preform by casting an organic, resin-based liquid mixture into a mold and subsequently heat treating it in two steps, which cures and pyrolizes the resin resulting in a porous carbon preform. By varying the amounts of the constituents in the organic, resin-based liquid mixture, control over the density of the carbon preform is obtained. Control of the density and microstructure of the carbon preform allows for determination of the microstructure and properties of the refractory metal carbide material produced. The glassy carbon preform is placed on a bed of refractory metal or refractory metal--silicon alloy. The pieces are heated above the melting point of the metal or alloy. The molten metal wicks inside the porous carbon preform and reacts, forming the refractory metal carbide or refractory metal carbide plus a minor secondary phase.

  15. Oxide Scales Formed on NiTi and NiPtTi Shape Memory Alloys

    NASA Technical Reports Server (NTRS)

    Smialek, James L.; Garg, Anita; Rogers, Richard B.; Noebe, Ronald D.

    2011-01-01

    Ni-49Ti and Ni-30Pt-50Ti (at.%) shape memory alloys were oxidized isothermally in air over the temperature range of 500 to 900 C. The microstructure, composition, and phase content of the scales were studied by SEM, EDS, XRD, and metallography. Extensive plan view SEM/EDS identified various features of intact or spalled scale surfaces. The outer surface of the scale was a relatively pure TiO2 rutile structure, typified by a distinct highly striated and faceted crystal morphology. Crystal size increased significantly with temperature. Spalled regions exhibited some porosity and less distinct features. More detailed information was obtained by correlation of SEM/EDS studies of 700 C/100 hr cross-sections with XRD analyses of serial or taper-polishing of plan surfaces. Overall, multiple layers exhibited graded mixtures of NiO, TiO2, NiTiO3, Ni(Ti) or Pt(Ni,Ti) metal dispersoids, Ni3Ti or Pt3Ti depletion zones, and substrate, in that order. The NiTi alloy contained a 3 at.% Fe impurity that appeared in embedded localized Fe-Ti-rich oxides, while the NiPtTi alloy contained a 2 v/o dispersion of TiC that appeared in lower layers. The oxidation kinetics of both alloys (in a previous report) indicated parabolic growth and an activation energy (250 kJ/mole) near those reported in other Ti and NiTi studies. This is generally consistent with TiO2 existing as the primary scale constituent, as described here.

  16. Influence of fourfold anisotropy form on hysteresis loop shape in ferromagnetic nanostructures

    SciTech Connect

    Ehrmann, Andrea; Blachowicz, Tomasz

    2014-08-15

    The dependence of the form of different mathematical depictions of fourfold magnetic anisotropies has been examined, using a simple macro-spin model. Strong differences in longitudinal and transverse hysteresis loops occur due to deviations from the usual phenomenological model, such as using absolute value functions. The proposed possible models can help understanding measurements on sophisticated magnetic nanosystems, like exchange bias layered structures employed in magnetic hard disk heads or magnetic nano-particles, and support the development of solutions with specific magnetization reversal behavior needed in novel magneto-electronic devices.

  17. Influence of fourfold anisotropy form on hysteresis loop shape in ferromagnetic nanostructures

    NASA Astrophysics Data System (ADS)

    Ehrmann, Andrea; Blachowicz, Tomasz

    2014-08-01

    The dependence of the form of different mathematical depictions of fourfold magnetic anisotropies has been examined, using a simple macro-spin model. Strong differences in longitudinal and transverse hysteresis loops occur due to deviations from the usual phenomenological model, such as using absolute value functions. The proposed possible models can help understanding measurements on sophisticated magnetic nanosystems, like exchange bias layered structures employed in magnetic hard disk heads or magnetic nano-particles, and support the development of solutions with specific magnetization reversal behavior needed in novel magneto-electronic devices.

  18. Synthesis and new structure shaping mechanism of silica particles formed at high pH

    NASA Astrophysics Data System (ADS)

    Zhang, Henan; Zhao, Yu; Akins, Daniel L.

    2012-10-01

    For the sol-gel synthesis of silica particles under high pH catalytic conditions (pH>12) in water/ethanol solvent, we have deduced that the competing dynamics of chemical etching and sol-gel process can explain the types of silica particles formed and their morphologies. We have demonstrated that emulsion droplets that are generated by adding tetraethyl orthosilicate (TEOS) to a water-ethanol solution serve as soft templates for hollow spherical silica (1-2 μm). And if the emulsion is converted by the sol-gel process, one finds that suspended solid silica spheres of diameter of ˜900 nm are formed. Moreover, several other factors are found to play fundamental roles in determining the final morphologies of silica particles, such as by variation of the pH (in our case, using OH-) to a level where condensation dominates; by changing the volume ratios of water/ethanol; and using an emulsifier (specifically, CTAB)

  19. Synthesis and new structure shaping mechanism of silica particles formed at high pH

    SciTech Connect

    Zhang, Henan; Zhao, Yu; Akins, Daniel L.

    2012-10-15

    For the sol-gel synthesis of silica particles under high pH catalytic conditions (pH>12) in water/ethanol solvent, we have deduced that the competing dynamics of chemical etching and sol-gel process can explain the types of silica particles formed and their morphologies. We have demonstrated that emulsion droplets that are generated by adding tetraethyl orthosilicate (TEOS) to a water-ethanol solution serve as soft templates for hollow spherical silica (1-2 {mu}m). And if the emulsion is converted by the sol-gel process, one finds that suspended solid silica spheres of diameter of {approx}900 nm are formed. Moreover, several other factors are found to play fundamental roles in determining the final morphologies of silica particles, such as by variation of the pH (in our case, using OH{sup -}) to a level where condensation dominates; by changing the volume ratios of water/ethanol; and using an emulsifier (specifically, CTAB) - Graphical abstract: 'Local chemical etching' and sol-gel process have been proposed to interpret the control of morphologies of silica particles through varying initial pHs in syntheses. Highlights: Black-Right-Pointing-Pointer Different initial pHs in our syntheses provides morphological control of silica particles. Black-Right-Pointing-Pointer 'Local chemical etching' and sol-gel process describes the formation of silica spheres. Black-Right-Pointing-Pointer The formation of emulsions generates hollow silica particles.

  20. Grazers and vitamins shape chain formation in a bloom-forming dinoflagellate, Cochlodinium polykrikoides.

    PubMed

    Jiang, Xiaodong; Lonsdale, Darcy J; Gobler, Christopher J

    2010-10-01

    Predators influence the phenotype of prey through both natural selection and induction. We investigated the effects of grazers and nutrients on chain formation in a dinoflagellate, Cochlodinium polykrikoides, which forms dense blooms and has deleterious effects on marine ecosystems around the world. Field populations of C. polykrikoides formed longer chains than laboratory cultures without grazers. In the field, chain length of C. polykrikoides was positively correlated with the abundance of the copepod Acartia tonsa. Chain length of C. polykrikoides increased when exposed to live females of A. tonsa or its fresh (<24 h post-isolation) exudates for 48 h. These results suggest that dissolved chemical cues released by A. tonsa induce chain formation in C. polykrikoides. Ingestion rate of A. tonsa on four-cell chains of C. polykrikoides was lower than on single cells, suggesting that chain formation may be an effective anti-grazing defense. Finally, nutrient amendment experiments demonstrated that vitamins (B(1), B(7), and B(12)) increased the chain length of C. polykrikoides both singly and collectively, while trace metals and inorganic nutrients did not, showing that vitamins may also influence chain formation in this species.

  1. Visual Experience Shapes Orthographic Representations in the Visual Word Form Area

    PubMed Central

    Wimmer, Heinz; Ludersdorfer, Philipp; Richlan, Fabio; Kronbichler, Martin

    2016-01-01

    Current neurocognitive research suggests that the efficiency of visual word recognition rests on abstract memory representations of written letters and words stored in the visual word form area (VWFA) in the left ventral occipitotemporal cortex. These representations are assumed to be invariant to visual characteristics such as font and case. In the present functional MRI study, we tested this assumption by presenting written words and varying the case format of the initial letter of German nouns (which are always capitalized) as well as German adjectives and adverbs (both usually in lowercase). As evident from a Word Type × Case Format interaction, activation in the VWFA was greater to words presented in unfamiliar case formats relative to familiar case formats. Our results suggest that neural representations of written words in the VWFA are not fully abstract and still contain information about the visual format in which words are most frequently perceived. PMID:27435995

  2. Optical methods for measurements of surface shape in optical components for high power laser beam forming

    NASA Astrophysics Data System (ADS)

    Józwik, Michał; Trusiak, Maciej; LiŻewski, Kamil; Martínez-Carranza, Juan; Voznesenskiy, Nikolay; Kujawińska, Małgorzata

    2016-12-01

    The paper presents modifications of full-field optical methods commonly used to test the surface quality of optical components used for forming a high power laser beam and tests of a final wavefront. The modifications in reference to surface measurements rely on implementation of the novel fringe pattern processing methods including the quality improvement of initial interferogram and analysis of a reconstructed phase based on Hilbert-Huang transform aided by the principal component analysis. Also the Point Diffraction Interferometer as the efficient tool for high quality measurements of elements with high NA is introduced. In reference to a wavefront quality measurements two solutions are discussed: the use of a lateral shear interferometer and the system employing Transport of Intensity Equation method. The pros and cons for both methods are discussed.

  3. On the Shape of Meissner Solutions to a Limiting Form of Ginzburg-Landau Systems

    NASA Astrophysics Data System (ADS)

    Xiang, Xingfei

    2016-12-01

    In this paper we study a semilinear system involving the curl operator, which is a limiting form of the Ginzburg-Landau model for superconductors in R^3 for a large value of the Ginzburg-Landau parameter. We consider the locations of the maximum points of the magnitude of solutions, which are associated with the nucleation of instability of the Meissner state for superconductors when the applied magnetic field is increased in the transition between the Meissner state and the vortex state. For small penetration depth, we prove that the location is not only determined by the tangential component of the applied magnetic field, but also by the normal curvatures of the boundary in some directions. This improves the result obtained by Bates and Pan in Commun. Math. Phys. 276, 571-610 (2007). We also show that the solutions decay exponentially in the normal direction away from the boundary if the penetration depth is small.

  4. Division of labor: subsets of dorsal-appendage-forming cells control the shape of the entire tube.

    PubMed

    Boyle, Michael J; French, Rachael L; Cosand, K Amber; Dorman, Jennie B; Kiehart, Daniel P; Berg, Celeste A

    2010-10-01

    The function of an organ relies on its form, which in turn depends on the individual shapes of the cells that create it and the interactions between them. Despite remarkable progress in the field of developmental biology, how cells collaborate to make a tissue remains an unsolved mystery. To investigate the mechanisms that determine organ structure, we are studying the cells that form the dorsal appendages (DAs) of the Drosophila melanogaster eggshell. These cells consist of two differentially patterned subtypes: roof cells, which form the outward-facing roof of the lumen, and floor cells, which dive underneath the roof cells to seal off the floor of the tube. In this paper, we present three lines of evidence that reveal a further stratification of the DA-forming epithelium. Laser ablation of only a few cells in the anterior of the region causes a disproportionately severe shortening of the appendage. Genetic alteration through the twin peaks allele of tramtrack69 (ttk(twk)), a female-sterile mutation that leads to severely shortened DAs, causes no such shortening when removed from a majority of the DA-forming cells, but rather, produces short appendages only when removed from cells in the very anterior of the tube-forming tissue. Additionally we show that heterotrimeric G-protein function is required for DA morphogenesis. Like TTK69, Gbeta 13F is not required in all DA-forming follicle cells but only in the floor and leading roof cells. The different phenotypes that result from removal of Gbeta 13F from each region demonstrate a striking division of function between different DA-forming cells. Gbeta mutant floor cells are unable to control the width of the appendage while Gbeta mutant leading roof cells fail to direct the elongation of the appendage and the convergent-extension of the roof-cell population.

  5. Mars life: how Darwinian pressures might have shaped its form and function

    NASA Astrophysics Data System (ADS)

    Levin, Gilbert V.

    2005-09-01

    The possible existence of life on Mars is now gaining credence. Evidence consistent with or supporting the presence of extant microbial life, as reported by a life detection experiment on the Viking Mission in 1976, has been rapidly accumulating from spacecraft orbital and lander operations, and from terrestrial observations. Vast oceans of frozen water near the planet's surface are being discovered, with strong indications of recent or present liquid flows, and theory and laboratory experiment have demonstrated that liquid water should exist on the surface of Mars. The biosphere on Earth has been extended into extreme environments until recently thought inimical to life. Places void of life have become rare. No life requirement has been found lacking on Mars. It is possible that, by the time of this 50th Anniversary SPIE Meeting, the paradigm shift accepting life beyond the Earth may have been made. Mankind will then emerge from its ancient fear of loneliness into a new fear of anticipation of what that still unidentified life might portend. The author attempts to apply Darwinian principles of evolution to life on Mars under the selection pressures, opportunities and constraints that have been imposed by past and present Martian conditions. Starting with the type of cell believed to have begun the evolutionary process on Earth, he speculates on what the current life on Mars may be like in form and function, including what threat or promise it might hold for Earth life.

  6. Root phototropism: how light and gravity interact in shaping plant form

    NASA Technical Reports Server (NTRS)

    Kiss, John Z.; Correll, Melanie J.; Mullen, Jack L.; Hangarter, Roger P.; Edelmann, Richard E.

    2003-01-01

    The interactions among tropisms can be critical in determining the final growth form of plants and plant organs. We have studied tropistic responses in roots as an example of these type of interactions. While gravitropism is the predominant tropistic response in roots, phototropism also plays a role in the oriented growth in this organ in flowering plants. In blue or white light, roots exhibit negative phototropism, but red light induces positive phototropism. In the flowering plant Arabidopsis, the photosensitive pigments phytochrome A (phyA) and phytochrome B (phyB) mediate this positive red-light-based photoresponse in roots since single mutants (and the double phyAB mutant) were severely impaired in this response. While blue-light-based negative phototropism is primarily mediated by the phototropin family of photoreceptors, the phyA and phyAB mutants (but not phyB) were inhibited in this response relative to the WT. The differences observed in phototropic responses were not due to growth limitations since the growth rates among all the mutants tested were not significantly different from that of the WT. Thus, our study shows that the blue-light and red-light systems interact in plants and that phytochrome plays a key role in integrating multiple environmental stimuli.

  7. Hemispheric Differences in Processing Handwritten Cursive

    ERIC Educational Resources Information Center

    Hellige, Joseph B.; Adamson, Maheen M.

    2007-01-01

    Hemispheric asymmetry was examined for native English speakers identifying consonant-vowel-consonant (CVC) non-words presented in standard printed form, in standard handwritten cursive form or in handwritten cursive with the letters separated by small gaps. For all three conditions, fewer errors occurred when stimuli were presented to the right…

  8. Hemispheric Asymmetries in Children.

    ERIC Educational Resources Information Center

    Lewandowski, Lawrence

    1982-01-01

    Hemispheric specialization tasks were given to different-aged boys. Asymmetries were demonstrated on manual, visual, and auditory tasks; however, the degree of asymmetries did not change across age groups. There appears to be a dissociation between visual and auditory perceptual asymmetries. (Author/RD)

  9. Hemispheric lateralization in reasoning.

    PubMed

    Turner, Benjamin O; Marinsek, Nicole; Ryhal, Emily; Miller, Michael B

    2015-11-01

    A growing body of evidence suggests that reasoning in humans relies on a number of related processes whose neural loci are largely lateralized to one hemisphere or the other. A recent review of this evidence concluded that the patterns of lateralization observed are organized according to two complementary tendencies. The left hemisphere attempts to reduce uncertainty by drawing inferences or creating explanations, even at the cost of ignoring conflicting evidence or generating implausible explanations. Conversely, the right hemisphere aims to reduce conflict by rejecting or refining explanations that are no longer tenable in the face of new evidence. In healthy adults, the hemispheres work together to achieve a balance between certainty and consistency, and a wealth of neuropsychological research supports the notion that upsetting this balance results in various failures in reasoning, including delusions. However, support for this model from the neuroimaging literature is mixed. Here, we examine the evidence for this framework from multiple research domains, including an activation likelihood estimation analysis of functional magnetic resonance imaging studies of reasoning. Our results suggest a need to either revise this model as it applies to healthy adults or to develop better tools for assessing lateralization in these individuals.

  10. Net Shape Spin Formed Cryogenic Aluminum Lithium Cryogenic Tank Domes for Lower Cost Higher Performance Launch Vehicles

    NASA Technical Reports Server (NTRS)

    Curreri, Peter A.; Hoffman, Eric; Domack, Marcia; Brewster, Jeb; Russell, Carolyn

    2013-01-01

    With the goal of lower cost (simplified manufacturing and lower part count) and higher performance (higher strength to weight alloys) the NASA Technical Maturation Program in 2006 funded a proposal to investigate spin forming of space launch vehicle cryogenic tank domes. The project funding continued under the NASA Exploration Technology Development Program through completion in FY12. The first phase of the project involved spin forming of eight, 1 meter diameter "path finder" domes. Half of these were processed using a concave spin form process (MT Aerospace, Augsburg Germany) and the other half using a convex process (Spincraft, Boston MA). The convex process has been used to produce the Ares Common Bulkhead and the concave process has been used to produce dome caps for the Space Shuttle light weight external tank and domes for the NASDA H2. Aluminum Lithium material was chosen because of its higher strength to weight ratio than the Aluminum 2219 baseline. Aluminum lithium, in order to obtain the desired temper (T8), requires a cold stretch after the solution heat treatment and quench. This requirement favors the concave spin form process which was selected for scale up. This paper describes the results of processing four, 5.5 meter diameter (upper stage scale) net shaped spin formed Aluminum Lithium domes. In order to allow scalability beyond the limits of foundry and rolling mills (about 12 foot width) the circular blank contained one friction stir weld (heavy lifter scales require a flat blank containing two welds). Mechanical properties data (tensile, fracture toughness, stress corrosion, and simulated service testing) for the parent metal and weld will also be discussed.

  11. Free-form Airfoil Shape Optimization Under Uncertainty Using Maximum Expected Value and Second-order Second-moment Strategies

    NASA Technical Reports Server (NTRS)

    Huyse, Luc; Bushnell, Dennis M. (Technical Monitor)

    2001-01-01

    Free-form shape optimization of airfoils poses unexpected difficulties. Practical experience has indicated that a deterministic optimization for discrete operating conditions can result in dramatically inferior performance when the actual operating conditions are different from the - somewhat arbitrary - design values used for the optimization. Extensions to multi-point optimization have proven unable to adequately remedy this problem of "localized optimization" near the sampled operating conditions. This paper presents an intrinsically statistical approach and demonstrates how the shortcomings of multi-point optimization with respect to "localized optimization" can be overcome. The practical examples also reveal how the relative likelihood of each of the operating conditions is automatically taken into consideration during the optimization process. This is a key advantage over the use of multipoint methods.

  12. Right hemispheric dominance of visual phenomena evoked by intracerebral stimulation of the human visual cortex.

    PubMed

    Jonas, Jacques; Frismand, Solène; Vignal, Jean-Pierre; Colnat-Coulbois, Sophie; Koessler, Laurent; Vespignani, Hervé; Rossion, Bruno; Maillard, Louis

    2014-07-01

    Electrical brain stimulation can provide important information about the functional organization of the human visual cortex. Here, we report the visual phenomena evoked by a large number (562) of intracerebral electrical stimulations performed at low-intensity with depth electrodes implanted in the occipito-parieto-temporal cortex of 22 epileptic patients. Focal electrical stimulation evoked primarily visual hallucinations with various complexities: simple (spot or blob), intermediary (geometric forms), or complex meaningful shapes (faces); visual illusions and impairments of visual recognition were more rarely observed. With the exception of the most posterior cortical sites, the probability of evoking a visual phenomenon was significantly higher in the right than the left hemisphere. Intermediary and complex hallucinations, illusions, and visual recognition impairments were almost exclusively evoked by stimulation in the right hemisphere. The probability of evoking a visual phenomenon decreased substantially from the occipital pole to the most anterior sites of the temporal lobe, and this decrease was more pronounced in the left hemisphere. The greater sensitivity of the right occipito-parieto-temporal regions to intracerebral electrical stimulation to evoke visual phenomena supports a predominant role of right hemispheric visual areas from perception to recognition of visual forms, regardless of visuospatial and attentional factors.

  13. Brain Hemisphericity and Developmental Dyslexia

    ERIC Educational Resources Information Center

    Vlachos, Filippos; Andreou, Eleni; Delliou, Afroditi

    2013-01-01

    The present study examined the link between brain hemisphericity and dyslexia in secondary school students, using the Preference Test (PT), a widely used self-report index of preferred hemisphere thinking styles. The hypothesis was that differences would be revealed between the dyslexic group and their peers in hemispheric preference. A total of…

  14. Does a Causal Relation Exist between the Functional Hemispheric Asymmetries of Visual Processing Subsystems?

    ERIC Educational Resources Information Center

    Andresen, David R.; Marsolek, Chad J.

    2005-01-01

    Past research indicates that specific shape recognition and spatial-relations encoding rely on subsystems that exhibit right-hemisphere advantages, whereas abstract shape recognition and spatial-relations encoding rely on subsystems that exhibit left-hemisphere advantages. Given these apparent regularities, we tested whether asymmetries in shape…

  15. Triton's Southern Hemisphere

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This polar projection of Triton's southern hemisphere provides a view of the southern polar cap and bright equatorial fringe. The margin of the cap is scalloped and ranges in latitude from +10 degrees to -30 degrees. The bright fringe is closely associated with the cap's margin; from it, diffuse bright rays extend north-northeast for hundreds of kilometers. The bright fringe probably consists of very fresh nitrogen frost or snow, and the rays consist of bright-fringe materials that were redistributed by north-moving Coriolis-deflected winds.

  16. Hemispherical latching apparatus

    NASA Technical Reports Server (NTRS)

    Clark, K. H. (Inventor)

    1985-01-01

    An apparatus for securing payloads in a space vehicle such as the space shuttle is described. The apparatus includes many latching assemblies carried by a platform on the vehicle and a like number of latching elements carried by the payload and adapted to mate with the latching assemblies. The novelty of the invention is believed to reside in the use of complementary hemispherical elements which automatically align and engage with one another. This enables a simple but effective mode of operation and avoids the need for hinged linkages and similar moving parts.

  17. Detailed Cloud Patterns in Martian Northern Hemisphere

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Cold and cloudy mornings; cool, hazy afternoons. High winds aloft and weather fronts moving slowly to the east. It is winter in the Martian northern hemisphere. One of the many reasons to study Mars is that, at times, its weather is very 'Earth-like.' At this time of the Martian year, clouds are abundant, especially in the morning and especially in the high northern latitudes. Clouds and fogs are also observed in low-lying areas farther to the south, in some lowlands they are as far south as the equator.

    The above color composite images, obtained by Mars Global Surveyor's camera on June 4, 1998, illustrate this Martian 'weather report.' Most of the thick, white clouds seen here occur north of latitude 35oN (roughly equivalent to Albuquerque NM, Memphis TN, and Charlotte, NC). Fog (seen as bright orange because it is lighter than the ground but some of the ground is still visible) occupies the lowest portions of the Kasei Valles outflow channel around 30oN and at 25oN.

    Several different types of cloud features are seen. The repetitious, wash-board pattern of parallel lines are 'gravity wave clouds'. These commonly form, in the lee--downwind side-- of topographic features such as mountain ranges (on Earth) or crater rims (on Mars), under very specific atmospheric conditions (low temperatures, high humidity, and high wind speeds). In this area, the wave clouds are lower in the atmosphere than some of the other clouds. These other clouds show attributes reflecting more the regional weather pattern, occasionally showing the characteristic 'slash' shape (southwest to northeast) of a weather front. These clouds probably contain mostly crystals of water ice but, depending on the temperature at high altitude (and more likely closer to the pole), some could also contain frozen carbon dioxide ('dry ice').

    MOC images 34501 (the red wide angle image) and 34502 (the blue wide angle image) were obtained on Mars Global Surveyor's 345th orbit about the planet

  18. Bio-inspired hemispherical compound eye camera

    NASA Astrophysics Data System (ADS)

    Xiao, Jianliang; Song, Young Min; Xie, Yizhu; Malyarchuk, Viktor; Jung, Inhwa; Choi, Ki-Joong; Liu, Zhuangjian; Park, Hyunsung; Lu, Chaofeng; Kim, Rak-Hwan; Li, Rui; Crozier, Kenneth B.; Huang, Yonggang; Rogers, John A.

    2014-03-01

    Compound eyes in arthropods demonstrate distinct imaging characteristics from human eyes, with wide angle field of view, low aberrations, high acuity to motion and infinite depth of field. Artificial imaging systems with similar geometries and properties are of great interest for many applications. However, the challenges in building such systems with hemispherical, compound apposition layouts cannot be met through established planar sensor technologies and conventional optics. We present our recent progress in combining optics, materials, mechanics and integration schemes to build fully functional artificial compound eye cameras. Nearly full hemispherical shapes (about 160 degrees) with densely packed artificial ommatidia were realized. The number of ommatidia (180) is comparable to those of the eyes of fire ants and bark beetles. The devices combine elastomeric compound optical elements with deformable arrays of thin silicon photodetectors, which were fabricated in the planar geometries and then integrated and elastically transformed to hemispherical shapes. Imaging results and quantitative ray-tracing-based simulations illustrate key features of operation. These general strategies seem to be applicable to other compound eye devices, such as those inspired by moths and lacewings (refracting superposition eyes), lobster and shrimp (reflecting superposition eyes), and houseflies (neural superposition eyes).

  19. Optimization of the preform shape in the three-stage forming process of the shielded slot plate in fuel cell manufacturing

    NASA Astrophysics Data System (ADS)

    Yang, Dong-Yol; Lee, Chang-Whan; Kang, Dong-Woo; Chang, In-Gab; Lee, Tae-Won

    2013-05-01

    The shielded slot plate, a repeated structure of high sheared protrusions, is a major component of metallic bipolar plates for the molten carbonate fuel cell (MCFC). In order to increase the efficiency of the MCFC and long-term operation capability, the sheared protrusion should have a relatively large flat contact area. In addition, defects from the forming process such as local thinning should be minimized. In this work, the preform shape in the three-stage forming process that integrates the slitting process, the preforming process, and the final forming process was optimized to minimize the effective plastic strain. In the simulation of the forming process, the ductile fracture criterion was employed to the user material subroutine VUMAT in ABAQUS/Explicit. Steepest descent method was utilized in the design of the forming process to minimize equivalent plastic strain. High sheared protrusions were manufactured without defects from the three-stage forming process using the optimized preform shape. The minimum thickness of one sheared protrusion was increased by 25% over that of the two-stage forming process. The three-stage forming process using the optimized preform shape enables more uniformly distributed deformation and reduces localized deformation.

  20. Shapes of standing jumps formed in granular flows down inclines: implications for the design of snow avalanche protection dams

    NASA Astrophysics Data System (ADS)

    Faug, Thierry; Childs, Philippa; Wyburn, Edward; Castro, Luiza Cardoso Ribas e.; Einav, Itai

    2015-04-01

    The European guidelines for the design of avalanche protection dams mainly rely on a couple of criteria based on the formation of granular jumps upstream of obstacles. The equations proposed to describe granular jumps are strictly valid for incompressible and frictionless fluids but generally hold for rapid granular flows mimicking snow avalanches. We have conducted a series of tests on a newly established granular chute to investigate in detail the shape of the steady jumps by varying both the slope angle and the mass discharge. Our laboratory tests confirm that the traditional shallow-water shock equation works well for the steep jumps formed in rapid and dense flows (characterized by a Froude number in the range 4-7 at high inclination and high mass discharge) but the equation fails for either low slope angles or low mass discharges. At low slope angles and high mass discharges, the jumps are very diffuse and elongated. The traditional shock equation underestimates the jump height. At low mass discharges, the incoming flows become dilute and produce compressible jumps for which the density variation across the jump cannot be neglected. A full jump equation accounting for the source terms (weight of the jump itself minus its effective friction) and the density variation as well is proposed. Approximate solutions are discussed to describe the transition between steep and diffuse jumps on the one side and the transition from incompressible to compressible jumps on the other side. Our study clearly reveals the limits of the current European guidelines for the design of avalanche protection dams when the incoming flows are relatively slow (Froude number about 1-3 in our tests). The latter avalanche flow-regime is relevant for many situations in avalanche run-out zones where protection dams are generally settled.

  1. Left Hemisphere Dysfunction and Left Hemisphere Overactivation in Schizophrenia

    ERIC Educational Resources Information Center

    Gur, Raquel E.

    1978-01-01

    Reports two studies relating schizophrenia to functional brain asymmetry. The first study found support for the hypothesis of left hemisphere dysfunction in schizophrenia, occurring at a rather early stage of information processing; the second study, using eye directionality as a measure of hemispheric activation, found that schizophrenics…

  2. Europa Hemispherical Globes

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The images used for the base of this globe were chosen from coverage supplied by the Galileo solid-state imaging (SSI) camera and Voyager 1 and 2 spacecraft. The individual images were radiometrically calibrated and photometrically normalized using a Lunar-Lambert function with empirically derived values. A linear correction based on the statistics of all overlapping areas was then applied to minimize image brightness variations. The image data were selected on the basis of overall image quality, reasonable original input resolution (from 20 km/pixel for gap fill to as much as 200 m/pixel), and availability of moderate emission/incidence angles for topography. Although consistency was achieved where possible, different filters were included for global image coverage as necessary: clear/blue for Voyager 1 and 2, and clear, near-IR (757 nm), and green (559 nm) for Galileo SSI. Individual images were projected to a Sinusoidal Equal-Area projection at an image resolution of 500 m/pixel, and a final global mosaic was constructed in this same Sinusoidal projection.

    The global mosaic was then reprojected so that the entire surface of Europa is portrayed in a manner suitable for the production of a globe. A specialized program was used to create the 'flower petal' appearance of the images; the area of each petal from 0 to 75 degrees latitude is in the Transverse Mercator projection, and the area from 75 to 90 degrees latitude is in the Lambert Azimuthal Equal-Area projection. The projections for adjacent petals overlap by 2 degrees of longitude, so that some features are shown twice.

    Names shown on the globe are approved by the International Astronomical Union. The number, size, and placement of text were chosen for a 9-inch globe. A complete list of Europa nomenclature can be found at the Gazetteer of Planetary Nomenclature at http://planetarynames.wr.usgs.gov. The northern hemisphere is shown on the left, and the southern hemisphere is shown on the right.

  3. Callisto Hemispherical Globes

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The images used for the base of this globe were chosen from the best image quality and moderate resolution coverage supplied by Galileo SSI and Voyager 1 and 2 (Batson, 1987; Becker and others, 1998; Becker and others, 1999; Becker and others, 2001). The digital map was produced using Integrated Software for Imagers and Spectrometers (ISIS) (Eliason, 1997; Gaddis and others, 1997; Torson and Becker, 1997). The individual images were radiometrically calibrated and photometrically normalized using a Lunar-Lambert function with empirically derived values (McEwen, 1991; Kirk and others, 2000). A linear correction based on the statistics of all overlapping areas was then applied to minimize image brightness variations. The image data were selected on the basis of overall image quality, reasonable original input resolution (from 20 km/pixel for gap fill to as much as 150 m/pixel), and availability of moderate emission/incidence angles for topography. Although consistency was achieved where possible, different filters were included for global image coverage as necessary: clear for Voyager 1 and 2; clear and green (559 nm) for Galileo SSI. Individual images were projected to a Sinusoidal Equal-Area projection at an image resolution of 1.0 kilometer/pixel, and a final global mosaic was constructed in this same projection. The final mosaic was enhanced using commercial software. The global mosaic was then reprojected so that the entire surface of Callisto is portrayed in a manner suitable for the production of a globe. A specialized program was used to create the 'flower petal' appearance of the images; the area of each petal from 0 to 75 degrees latitude is in the Transverse Mercator projection, and the area from 75 to 90 degrees latitude is in the Lambert Azimuthal Equal-Area projection. The projections for adjacent petals overlap by 2 degrees of longitude, so that some features are shown twice. The northern hemisphere is shown on the left, and the southern hemisphere is

  4. Identification of different shapes, colors and sizes of standard oral dosage forms in diabetes type 2 patients-A pilot study.

    PubMed

    Stegemann, Sven; Riedl, Regina; Sourij, Harald

    2017-01-30

    The clear identification of drug products by the patients is essential for a safe and effective medication management. In order to understand the impact of shape, size and color on medication identification a study was performed in subjects with type 2 diabetes mellitus (T2D). Ten model drugs differentiated by shape, size and color were evaluated using a mixed method of medication schedule preparation by the participants followed by a semi-structured interview. Detection times were fastest for the large round tablet shape and the bi-chromatic forms. Larger size was easier to identify than the smaller sizes except for the bi-chromatic forms. The shape was the major source of errors, followed by the size and the color dimension. The results from this study suggests that color as a single dimension are perceived more effectively by subjects with T2D compared to shape and size, which requires a more demanding processing of three dimension and is dependent on the perspective.

  5. Io's Kanehekili Hemisphere

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This color composite of Io, acquired by Galileo during its ninth orbit (C9) of Jupiter, shows the hemisphere of Io which is centered at longitude 52 degrees. The dark feature just to the lower right of the center of the disk is called Kanehekili. Named after an Hawaiian thunder god, Kanehekili contains two persistent high temperature hot spots and a 'new' active volcanic plume. NASA's Voyager spacecraft returned images of nine active plumes during its 1979 flyby of this dynamic satellite. To date, Galileo's plume monitoring observations have shown continued activity at four of those nine plume locations as well as new activity at six other locations.

    North is to the top of the picture which combines images acquired using violet, green, and near-infrared (756 micrometers) filters. The resolution is 21 kilometers per picture element. The images were taken on June 27, 1997 at a range of 1,033,000 kilometers by the solid state imaging (CCD) system on NASA's Galileo spacecraft.

    The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  6. Southern Hemisphere Polygonal Patterned Ground

    NASA Technical Reports Server (NTRS)

    2002-01-01

    On Earth, periglacial is a term that refers to regions and processes where cold climate contributes to the evolution of landforms and landscapes. Common in periglacial environments on Earth, such as the arctic of northern Canada,Siberia, and Alaska, is a phenomenon called patterned ground. The 'patterns' in patterned ground often take the form of large polygons, each bounded by either troughs or ridges made up of rock particles different in size from those seen in the interior of the polygon. On Earth, many polygons in periglacial environments are directly linked to water: they typically form from stresses induced by repeated freezing and thawing of water, contraction from stress induced by changing temperatures, and sorting of rocks brought to the surface along polygon boundaries by the freeze-thaw processes. Although not exclusively formed by freezing and thawing of water, that is often the dominant mechanism on Earth.

    Polygons similar to those found in Earth's arctic and antarctic regions are also found in the polar regions of Mars. Typically, they occur on crater floors, or on intercrater plains, between about 60o and 80o latitude. The polygons are best seen when bright frost or dark sand has been trapped in the troughs that form the polygon boundaries. Three examples of martian polygons seen by the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) are shown here. Each is located in the southern hemisphere:(left) Polygon troughs highlighted by frost as the south polar cap retreats during spring. The circular features are the locations of buried craters that were originally formed by meteor impact. This image, E09-00029, is located at 75.1oS, 331.3oW, and was acquired on 1 October 2001.(center) Summertime view of polygons, highlighted by dark, windblown sand, on the floor of a crater at 71.2oS, 282.6oW. The image, E12-02319, was obtained on 21January 2002.(right) Polygon troughs highlighted by the retreating south polar frost cap during southern summer

  7. Valles Marineris Hemisphere

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Mosaic composed of 102 Viking Orbiter images of Mars, covering nearly a full hemisphere of the planet (approximate latitude -55 to 60 degrees, longitude 30 to 130 degrees). The mosaic is in a point-perspective projection with a scale of about 1 km/pixel. The color variations have been enhanced by a factor of about two, and the large-scale brightness variations (mostly due to sun-angle variations) have been normalized by large-scale filtering. The center of the scene shows the entire Valles Marineris canyon system, over 3,000 km long and up to 8 km deep, extending from Noctis Labyrinthus, the arcuate system of graben to the west, to the chaotic terrain to the east. Bright white layers of material in the eastern canyons may consist of carbonates deposited in ancient lakes. Huge ancient river channels begin from the chaotic terrain and from north-central canyons and run north. Many of the channels flowed into a basin called Acidalia Planitia, which is the dark area in the extreme north of this picture. The Viking 1 landing site (Mutch Memorial Station) is located in Chryse Planitia, south of Acidalia Planitia. The three Tharsis volcanoes (dark red spots), each about 25 km high, are visible to the west. The large crater with two prominent rings located at the bottom of this image is named Lowell, after the Flagstaff astronomer. The images were acquired by Viking Orbiter 1 in 1980 during early northern summer on Mars (Ls = 70 degrees); the atmosphere was relatively dust-free. A variety of clouds appear as bright blue streaks and hazes, and probably consist of water ice. Long, linear clouds north of central Valles Marineris appear to emanate from impact craters.

  8. The Southern Hemisphere VLBI experiment

    SciTech Connect

    Preston, R.A.; Meier, D.L.; Louie, A.P.; Morabito, D.D.; Skjerve, L.; Slade, M.A.; Niell, A.E.; Wehrle, A.E.; Jauncey, D.L.; Tzioumis, A.K.; Haystack Observatory, Westford, MA; California Univ., Los Angeles; CSIRO, Div. of Radiophysics, Epping; Sydney Univ.; Manchester Victoria Univ., Jodrell Bank )

    1989-07-01

    Six radio telescopes were operated as the first Southern Hemisphere VLBI array in April and May 1982. Observations were made at 2.3 and 8.4 GHz. This array provided VLBI modeling and hybrid imaging of celestial radio sources in the Southern Hemisphere, high-accuracy VLBI geodesy between Southern Hemisphere sites, and subarcsecond radio astrometry of celestial sources south of declination -45 deg. The goals and implementation of the array are discussed, the methods of modeling and hybrid image production are explained, and the VLBI structure of the sources that were observed is summarized. 36 refs.

  9. [Hemispheric functional specialization and anxiety. Focus on an evaluation procedure].

    PubMed

    Perier, N; Boulenger, J P; Eustache, F; Bisserbe, J C; Lebreuilly, J; Zarifian, E

    1992-01-01

    Observations of brain-lesioned patients and experimental psychology studies have shown that the influence of the specific functioning of the two hemispheres of the brain on the regulation of emotional behaviour appears to be unequal and suggests a functional specialization of the right hemisphere for the expression and comprehension of the affective components of behaviour. However, the extension of this hypothesis to include all emotional experiences remains controversial. The observed superiority of the left hemisphere in the perception of positive emotions and the predominance of the right hemisphere in the treatment of negative emotions would appear to favour a joint and complementary participation of both cerebral hemispheres in emotional experiences. In the case of affective disorders, and particularly in anxiety symptoms, the hypothesis of a dysfunctioning of the right hemisphere is similarly questioned: while all metabolic studies corroborate this hypothesis, experimental psychological studies suggest the existence of a preferential involvement of one or the other hemisphere in relation to individual differences such as the "trait" anxiety score. Moreover, the few studies which have been undertaken with healthy volunteers raise the problem of their extrapolation to pathological situations. In view of the potential interest in the neuropsychological evaluations of subjects with different forms of pathological anxiety, we have developed an experimented with two tests aimed at evaluating the differential activity of the two hemispheres of the brain. These two tests, constructed on a "mirror-image" model from the specifications of a functional hemispheric specialization, are supposed to involve cognitive strategies pinpointing preferentially one hemisphere or the other.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. Archimedes and the Magdeburg Hemispheres

    ERIC Educational Resources Information Center

    Hayn, Carl H.

    1975-01-01

    Weights suspended from a lever arm separate evacuated hemispheres allowing estimation of atmospheric pressure to within five percent of the barometric reading. An illustration and a reference to von Guericke's demonstration are provided. (GH)

  11. Brain Hemispheres and Thinking Styles.

    ERIC Educational Resources Information Center

    Gray, Esther Cappon

    1980-01-01

    The author reviews some research, particularly that of Roger Sperry, substantiating the existence of different thinking styles in the two brain hemispheres and the development of this differentiation in infancy and childhood. She draws some implications for elementary teaching. (SJL)

  12. Asteroid survivability: The importance of asteroid shape and porosity and their possible influence on the Morokweng crater-forming impact

    NASA Astrophysics Data System (ADS)

    Potter, R. W.; Collins, G. S.

    2012-12-01

    The fate of an impacting asteroid is an important aspect of the cratering process. 'Surviving' asteroidal fragments, which can be used to infer the impactor's structure and composition, have been recovered from terrestrial impact sites. Because small impactors decelerate in the atmosphere, these finds are often associated with small, simple craters where fragments are found within, or proximal to, the impact crater. Impactor fragments have been recovered from large-scale impacts, such as Chicxulub, but from distal locations. Recently though, a collection of unmolten impactor fragments were recovered from within the highly meteoritic impact melt sheet of the large-scale (>70 km diameter) Morokweng crater, South Africa, demonstrating impactor material can survive large-scale impact events without melting and remain within the crater. The aim of this work is to investigate how impactor shape and porosity influence asteroid survivability in large-scale terrestrial impact events. To do this, we use 2D and 3D versions of the iSALE hydrocode to numerically model the first stage of crater formation, contact and compression, which determines whether the impactor remains solid, melts or vaporizes. By altering the ratio of the vertical and horizontal length of the impactors we produce a variety of oblate- (horizontal length > vertical length) and prolate- (vertical length > horizontal length) shaped impactors, keeping impactor volume constant. By defining our dunite impactor (a reasonable proxy for asteriodal material) as surviving if it experiences a peak shock pressure less than that required for incipient melting, we find increasing the oblateness of the impactor decreases survivability. Conversely, increasing the prolateness of the impactor increases survivability. This is likely due to impactor geometry and complex interactions between shock and release waves. The porosity of spherical impactors (with constant mass) was varied between 0% (non-porous) and 67% and showed

  13. Western Hemisphere Knowledge Partnerships

    NASA Astrophysics Data System (ADS)

    Malone, T. F.

    2001-05-01

    , and application of knowledge concerning the nature of -- and interaction among -- matter, living organisms, energy, information, and human behavior. This strategy calls for innovative partnerships among the physical, biological, health, and social sciences, engineering, and the humanities. New kinds of partnership must also be forged among academia, business and industry, governments, and nongovernmental organizations. Geophysicists can play an important role in these partnerships. A focus for these partnerships is to manage the individual economic productivity that drives both human development and global change. As world population approaches stability during the twenty-first century, individual economic productivity will be the critical link between the human and the natural systems on planet Earth. AGU is among a core group of individuals and institutions proposing Western Hemisphere Knowledge Partnerships (WHKP) to test the hypothesis that knowledge, broadly construed, is an important organizing principle in choosing a path into the future. The WHKP agenda includes: (1) life-long learning, (2) the health and resilience of natural ecosystems, (3) eco-efficiency in economic production and consumption, (4) extension of national income accounts, (5) environmentally benign sources of energy, (6) delivery of health care, (7) intellectual property rights, and (8) networks for action by local communities.Collaboratories and distance education technologies will be major tools. A panel of experts will explore this proposal.

  14. Experiments and computer simulations of the dynamic cavity formed by a particulated shaped-charge jet in sand

    SciTech Connect

    Simonson, S.C.; Winer, K.A.; Reaugh, J.E.; Breithaupt, R.D.; Baum, D.W.

    1995-02-28

    Experiments have been carried out to measure the dynamic cavity growth of dry sand during penetration by particulated jets from Viper 65-mm-diameter, Cu-lined conical shaped charges at 1,000-mm standoff. The sand target was instrumented with foil switches, piezoelectric pins, and pressure transducers. Flash radiography at 450-keV was used to characterize the jets before impact and to image the target hole during jet penetration. The authors have developed a dry sand equation of state based on existing Hugoniot data as input to a porous material model incorporated in the 2-D arbitrary Lagrangian-Eulerian hydrocode CALE. They have carried out sand penetration simulations in which the particulated jet is modeled as hot copper rods. By varying parameters in the sand and copper descriptions they identify those features that affect the dynamic cavity formation.

  15. Dynamic DNA devices and assemblies formed by shape-complementary, non-base pairing 3D components.

    PubMed

    Gerling, Thomas; Wagenbauer, Klaus F; Neuner, Andrea M; Dietz, Hendrik

    2015-03-27

    We demonstrate that discrete three-dimensional (3D) DNA components can specifically self-assemble in solution on the basis of shape-complementarity and without base pairing. Using this principle, we produced homo- and heteromultimeric objects, including micrometer-scale one- and two-stranded filaments and lattices, as well as reconfigurable devices, including an actuator, a switchable gear, an unfoldable nanobook, and a nanorobot. These multidomain assemblies were stabilized via short-ranged nucleobase stacking bonds that compete against electrostatic repulsion between the components' interfaces. Using imaging by electron microscopy, ensemble and single-molecule fluorescence resonance energy transfer spectroscopy, and electrophoretic mobility analysis, we show that the balance between attractive and repulsive interactions, and thus the conformation of the assemblies, may be finely controlled by global parameters such as cation concentration or temperature and by an allosteric mechanism based on strand-displacement reactions.

  16. Dynamic DNA devices and assemblies formed by shape-complementary, non-base pairing 3D components

    NASA Astrophysics Data System (ADS)

    Gerling, Thomas; Wagenbauer, Klaus F.; Neuner, Andrea M.; Dietz, Hendrik

    2015-03-01

    We demonstrate that discrete three-dimensional (3D) DNA components can specifically self-assemble in solution on the basis of shape-complementarity and without base pairing. Using this principle, we produced homo- and heteromultimeric objects, including micrometer-scale one- and two-stranded filaments and lattices, as well as reconfigurable devices, including an actuator, a switchable gear, an unfoldable nanobook, and a nanorobot. These multidomain assemblies were stabilized via short-ranged nucleobase stacking bonds that compete against electrostatic repulsion between the components’ interfaces. Using imaging by electron microscopy, ensemble and single-molecule fluorescence resonance energy transfer spectroscopy, and electrophoretic mobility analysis, we show that the balance between attractive and repulsive interactions, and thus the conformation of the assemblies, may be finely controlled by global parameters such as cation concentration or temperature and by an allosteric mechanism based on strand-displacement reactions.

  17. Colloidal processing of chemically prepared zinc oxide varistors. Part 2, near net shape forming and fired electrical properties.

    SciTech Connect

    Voigt, James A.; Tuttle, Bruce Andrew; Bell, Nelson Simmons; Dimos, Duane Brian

    2003-07-01

    Chemically prepared zinc oxide powders were processed for the production of high aspect ratio varistor components (length/diameter >5). Near-net-shape casting methods including slip casting and agarose gelcasting were evaluated for effectiveness in achieving a uniform green microstructure that densifies to near theoretical values during sintering. The structure of the green parts was examined by mercury porisimetry. Agarose gelcasting produced green parts having low solids loading values and did not achieve high fired density. Isopressing the agarose cast parts after drying raised the fired density to greater than 95%, but the parts exhibited catastrophic shorting during electrical testing. Slip casting produced high green density parts, which exhibit high fired density values. The electrical characteristics of slip-cast parts are comparable with dry-pressed powder compacts.

  18. Experimental and numerical investigation of cylindrical and hemispherical jet formation

    NASA Astrophysics Data System (ADS)

    Betney, Matthew; Foster, Peta; Ringrose, Tim; Edwards, Thomas; Tully, Brett; Doyle, Hugo; Hawker, Nicholas; First Light Fusion Ltd. Team

    2016-11-01

    This paper presents a detailed investigation of the formation of jets in cylindrical and spherical cavities, when impacted by shocks at extreme pressures. As the shock pressure increases the effects of material strength lessen in proportion. Beyond a certain magnitude the behaviour is referred to as "hydrodynamic". In this domain both cylindrical and spherical cavities involute to form jets, which go on to strike the leeward cavity wall, compressing the cavity contents to high pressures and temperatures. In this study, the jet formation process is isolated by cutting hemispherical and half-cylindrical cavities from the rear side of PMMA and copper blocks. This allows direct measurement of the jet speed and shape using high speed imaging, providing data against which numerical models may be compared. Shock waves at pressures of up to 30 GPa are formed in the targets by the impact of projectiles from a two-stage light gas gun, at velocities of up to 7 km/s. Numerically, the jet formation process is modelled using our in-house front-tracking code. This code uses Lagrangian hypersurfaces to model the interfaces between different media, with an underlying Eulerian mesh used to model the bulk flow. Detailed comparisons between numerical and experimental results are presented.

  19. Thrust Faulting as the Origin of Dorsa in the Trailing Hemisphere of Enceladus

    NASA Astrophysics Data System (ADS)

    Pappalardo, Robert T.; Crow-Willard, E.; Golombek, M.

    2010-10-01

    Several large ridges, or "dorsa,” located within a tectonically deformed region of the trailing hemisphere of Enceladus, have remained poorly understood since they were imaged in Feb. 2005. In map view these 2.5 km wide ridges can bifurcate in a branching manner, and in profile they appear to be somewhat trapezoidal or "boxy” in shape. Geological mapping of the trailing hemisphere's Sarandib and Diyar Planitiae (Crow-Willard and Pappalardo, 2009) suggests the dorsa cut across and deform older striated terrain, which consists of small-scale (200 m wide) ridges and troughs. A single high-resolution (65 m/pixel) Cassini image captures the western portions of the Cufa Dorsa, where ridges of the striated terrain are visible on the southern flanks. This relationship is inconsistent with a previously suggested cryovolcanic origin, and there is no evidence of surrounding embayment. Instead, the relationships suggest tectonic uplift to form the dorsa. We propose that these ridges were formed by thrust faulting; in particular, the Cufa Dorsa suggest formation above south-dipping master thrusts, as either fault-bend folds or more likely as fault-propagation folds. The high-resolution image reveals small ( 300 m) irregular crenulations atop the ridges, and shadow roughness indicates significant roughness at sub-pixel scale. The crenulations appear analogous to those atop wrinkle ridges on the Moon and Mars, and to the Yakima Ridges of eastern Washington state, which form via high-level back thrusts in layered materials above a relatively flat décollement. The Cufa Dorsa terminate to the west against a prominent trough, which may have served as a transcurrent fault that permitted north-south contraction. Bifurcation of the Cufa Dorsa is consistent with three-dimensional straining, if the dorsa resulted from multi-directional contraction. Perhaps a thermal uplift that initialized trailing hemisphere tectonic deformation subsequently cooled and collapsed to form the dorsa.

  20. Discourse functions and hemispheric asymmetry.

    PubMed

    Osiejuk, E

    1993-01-01

    This paper presents a review of the main results of an application of discourse analysis in aphasics with the left hemisphere damages and in the right hemisphere damaged (RHD) patients. Research findings indicate that aphasics have marked deficits on the level of microstructure, especially cohesion of discourse, whereas the coherence and superstructure of their texts are relatively well preserved. RHD patients show difficulties at the microstructure of discourse but not so marked as that of aphasic subjects. The main impairments of RHD patients' discourse can be observed at the level of text coherence. The both populations have also preserved cognitive representation concerned with script knowledge. Discourse processing at macrostructural level of discourse is affected in aphasics as well as in RHD patients. These results suggest that both hemispheres are necessary for normal discourse processes.

  1. Prediction of part shape and associated material properties in hot-press forming using Unite element analysis

    NASA Astrophysics Data System (ADS)

    Kim, Hwigeon; Ha, Jinjin; Lee, Myoung-Gyu; Barlat, Frederic

    2016-08-01

    The hot-press forming of a U-channel was conducted on a boron-steel blank. The die consisted of two separate parts in order to perform the partial quenching process. The cold die was initially at 25 °C while the heated die was set to five different temperatures, namely, 25, 120, 220, 320 and 400 °C. The cooling temperature history, Vickers hardness and springback of the channel were measured. A thermo-mechanical-metallurgical model, which accounts for the prior austenite deformation effect, was successfully implemented in the LS-DYNA explicit solver to simulate the hot-press forming process under partial quenching conditions. The predicted and experimental results were compared and found in reasonable agreement.

  2. Shape-Shifting Plastic

    SciTech Connect

    2015-05-20

    A new plastic developed by ORNL and Washington State University transforms from its original shape through a series of temporary shapes and returns to its initial form. The shape-shifting process is controlled through changes in temperature

  3. Flow past 2-D Hemispherical Rigid Canopies

    NASA Astrophysics Data System (ADS)

    Carnasciali, Maria-Isabel

    2013-11-01

    The flow past a 2-dimensional rigid hemispherical shape is investigated using PIV. Flow field measurements and images were generated with the use of a Thermoflow® apparatus. Results of this study are compared to prior work (APS DFD 2012 Session E9.00003) which employed CFD to investigate the flow in the near wake of hemispherical parachutes. The various sized gaps/open areas were positioned at distinct locations. The work presented here is part of a larger research project to investigate flow fields in deceleration devices and parachutes. Understanding the pitch-stability of parachutes is essential for accurate design and implementation of these deceleration devices but they present a difficult system to analyze. The flexibility of the parachute fabric results in large variations in the parachute geometry leading to complex fluid-structure interactions. Such flow, combined with flow through gaps and open areas, has been postulated to shed alternating vortices causing pitching/oscillations of the canopy. The results presented provide some insight into which geometric features affect vortex shedding and may enable the redesign of the baseline parachute to minimize instabilities.

  4. Mutism following left hemisphere infarction.

    PubMed Central

    David, A S; Bone, I

    1984-01-01

    A case of mutism due to left hemisphere infarction is described. Recovery revealed mild motor dysphasia. Review of the literature showed that the case resembles aphemia but is unique by virtue of its duration, and the absence of associated apraxia and paresis. Images PMID:6210346

  5. Math Learning: The Two Hemispheres.

    ERIC Educational Resources Information Center

    Grow, Meda F.; Johnson, Norbert

    1983-01-01

    Discusses the duality of mental processes, learning styles and brain research (concerning brain growth, hemispheric specialization, and sex differences) as they apply to teaching mathematics. Discusses the implications of these topics as well as individual learning styles and basics-versus-creative school curricula for curriculum development. (WAS)

  6. Numerical and experimental evaluation of laser forming process for the shape correction in ultra high strength steels

    SciTech Connect

    Song, J. H.; Lee, J.; Lee, S.; Kim, E. Z.; Lee, N. K.; Lee, G. A.; Park, S. J.; Chu, A.

    2013-12-16

    In this paper, laser forming characteristics in ultra high strength steel with ultimate strength of 1200MPa are investigated numerically and experimentally. FE simulation is conducted to identify the response related to deformation and characterize the effect of laser power, beam diameter and scanning speed with respect to the bending angle for a square sheet part. The thermo-mechanical behaviors during the straight-line heating process are presented in terms of temperature, stress and strain. An experimental setup including a fiber laser with maximum mean power of 3.0 KW is used in the experiments. From the results in this work, it would be easily adjustment the laser power and the scanning speed by controlling the line energy for a bending operation of CP1180 steel sheets.

  7. A lysigenic programmed cell death-dependent process shapes schizogenously formed aerenchyma in the stems of the waterweed Egeria densa

    PubMed Central

    Bartoli, G.; Forino, L. M. C.; Durante, M.; Tagliasacchi, A. M.

    2015-01-01

    Background and Aims Plant adaptation to submergence can include the formation of prominent aerenchyma to facilitate gas exchange. The aim of this study was to characterize the differentiation of the constitutive aerenchyma in the stem of the aquatic macrophyte Egeria densa (Hydrocharitaceae) and to verify if any form of cell death might be involved. Methods Plants were collected from a pool in a botanical garden. Aerenchyma differentiation and apoptotic hallmarks were investigated by light microscopy and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) assay coupled with genomic DNA extraction and gel electrophoresis (DNA laddering assay). Cell viability and the occurrence of peroxides and nitric oxide (NO) were determined histochemically using specific fluorogenic probes. Key Results Aerenchyma differentiation started from a hexagonally packed pre-aerenchymatic tissue and, following a basipetal and centripetal developmental pattern, produced a honeycomb arrangement. After an early schizogenous differentiation process, a late lysigenous programmed cell death- (PCD) dependent mechanism occurred. This was characterized by a number of typical apoptotic hallmarks, including DNA fragmentation, chromatin condensation, apoptotic-like bodies, partial cell wall lysis and plasmolysis. In addition, local increases in H2O2 and NO were observed and quantified. Conclusions The differentiation of cortical aerenchyma in the stem of E. densa is a complex process, consisting of a combination of an early schizogenous differentiation mechanism and a late lysigenous PCD-dependent process. The PCD remodels the architecture of the gas spaces previously formed schizogenously, and also results in a reduction of O2-consuming cells and in recycling of material derived from the lysigenic dismantling of the cells. PMID:26002256

  8. Superplastic forming of ceramic insulation

    NASA Technical Reports Server (NTRS)

    Nieh, T. G.; Wittenauer, J. P.; Wadsworth, J.

    1992-01-01

    Superplasticity has been demonstrated in many fine-grained structural ceramics and ceramic composites, including yttria-stabilized tetragonal zirconia polycrystal (YTZP), alumina, and Al2O3-reinforced zirconia (Al2O3/YTZ) duplex composites and SiC-reinforced Si3N4. These superplastic ceramics obviously offer the potential benefit of forming net shape or near net shape parts. This could be particularly useful for forming complicated shapes that are difficult to achieve using conventional forming techniques, or require elaborate, subsequent machining. In the present study, we successfully demonstrated the following: (1) superplastic 3Y-TXP and 20 percent Al2O3/YTZ composite have for the first time been successfully deformed into hemispherical caps via a biaxial gas-pressure forming technique; (2) no experimental difficulty was encountered in applying the required gas pressures and temperatures to achieve the results, thus, it is certain that higher rates of deformation than those presented in this study will be possible by using the current test apparatus at higher temperatures and pressures; and (3) an analytical model incorporating material parameters, such as variations during forming in the strain rate sensitivity exponent and grain growth-induced strain hardening, is needed to model accurately and therefore precisely control the biaxial gas-pressure forming of superplastic ceramics. Based on the results of this study, we propose to fabricate zirconia insulation tubes by superplastic extrusion of zirconia polycrystal. This would not only reduce the cost, but also improve the reliability of the tube products.

  9. In situ 3D topographic and shape analysis by synchrotron radiation X-ray microtomography for crystal form identification in polymorphic mixtures

    NASA Astrophysics Data System (ADS)

    Yin, Xian-Zhen; Xiao, Ti-Qiao; Nangia, Ashwini; Yang, Shuo; Lu, Xiao-Long; Li, Hai-Yan; Shao, Qun; He, You; York, Peter; Zhang, Ji-Wen

    2016-04-01

    Polymorphism denotes the existence of more than one crystal structure of a substance, and great practical and theoretical interest for the chemical and pharmaceutical industries. In many cases, it is challenging to produce a pure crystal form and establish a sensitive detection method for the identification of crystal form in a mixture of polymorphs. In this study, an accurate and sensitive method based on synchrotron radiation X-ray computed microtomography (SR-μCT) was devised to identify the polymorphs of clopidogrel bisulphate (CLP). After 3D reconstruction, crystal particles were extracted and dozens of structural parameters were calculated. Whilst, the particle shapes of the two crystal forms were all irregular, the surface of CLP II was found to be rougher than CLP I. In order to classify the crystal form based on the quantitative morphological property of particles, Volume Bias Percentage based on Surface Smoothing (VBP) was defined and a new method based on VBP was successfully developed, with a total matching rate of 99.91% for 4544 particles and a lowest detectable limit of 1%. More important for the mixtures in solid pharmaceutical formulations, the interference of excipients can be avoided, a feature cannot achieved by other available analytical methods.

  10. Mediated priming in the cerebral hemispheres.

    PubMed

    Livesay, Kay; Burgess, Curt

    2003-11-01

    The present experiment investigates hemispheric differences in mediated priming. Theories of lexical representation have argued for an asymmetrical coding between the right and left hemispheres ([Beeman, 1998]), claiming that the right hemisphere is more diffusely represented compared to the left hemisphere. Thus, the right hemisphere activates a larger semantic field compared to the left hemisphere. Mediated (two-step) priming is an ideal task to examine this representational claim, because of the distant nature of the prime-target pairs. Results showed no difference in the magnitude of priming (both mediated and direct) between the right and left hemispheres. These results suggest that the lexical representation of the two hemispheres is equivalent, not asymmetrical as Beeman suggests.

  11. Hemispheric ultra-wideband antenna.

    SciTech Connect

    Brocato, Robert Wesley

    2006-04-01

    This report begins with a review of reduced size ultra-wideband (UWB) antennas and the peculiar problems that arise when building a UWB antenna. It then gives a description of a new type of UWB antenna that resolves these problems. This antenna, dubbed the hemispheric conical antenna, is similar to a conventional conical antenna in that it uses the same inverted conical conductor over a ground plane, but it also uses a hemispheric dielectric fill in between the conductive cone and the ground plane. The dielectric material creates a fundamentally new antenna which is reduced in size and much more rugged than a standard UWB conical antenna. The creation of finite-difference time domain (FDTD) software tools in spherical coordinates, as described in SAND2004-6577, enabled this technological advance.

  12. Hemispheric superiority for processing a mirror image.

    PubMed

    Garren, R B; Gehlsen, G M

    1981-04-01

    39 adult subjects were administered a test using tachistoscopic half-field presentations to determine hemispheric dominance and a mirror-tracing task to determine if an hemispheric superiority exists for processing a mirror-image. The results indicate superiority of the nondominant hemisphere for this task.

  13. Hemispheric Specialization in Normal and Disabled Readers.

    ERIC Educational Resources Information Center

    Newell, David; Rugel, Robert P.

    1981-01-01

    Degree of hemispheric specialization in 32 normal and 32 disabled readers (9 to 12 years old) was evaluated using a linguistic task and a musical task. While normals demonstrated hemispheric specialization on these tasks in the expected directions, disabled readers showed a right hemisphere deficit. (Author)

  14. Emotional Television Scenes and Hemispheric Specialization.

    ERIC Educational Resources Information Center

    Reeves, Byron; And Others

    1989-01-01

    Examines hemispheric differences in cortical arousal as a function of positive and negative emotional television scenes. Finds that (1) the processing of emotional content is hemispherically asymmetric; and (2) negative material produced greater cortical arousal in the right hemisphere and positive material greater arousal in the left. (MS)

  15. Brain Hemispheric Functions and the Native American.

    ERIC Educational Resources Information Center

    Ross, Allen Chuck

    1982-01-01

    Uses brain research conducted by Dr. Roger Sperry to show that traditional Native Americans are more dominant in right hemisphere thinking, setting them apart from a modern left hemisphere-oriented society (especially emphasized in schools). Describes some characteristics of Native American thinking that illustrate a right hemisphere orientation…

  16. Hemispheric Laterality in Music and Math

    ERIC Educational Resources Information Center

    Szirony, Gary Michael; Burgin, John S.; Pearson, L. Carolyn

    2008-01-01

    Hemispheric laterality may be a useful concept in teaching, learning, training, and in understanding more about human development. To address this issue, a measure of hemispheric laterality was compared to musical and mathematical ability. The Human Information Processing Survey (HIPS) instrument, designed to measure hemispheric laterality, was…

  17. Right Hemisphere Dominance in Visual Statistical Learning

    ERIC Educational Resources Information Center

    Roser, Matthew E.; Fiser, Jozsef; Aslin, Richard N.; Gazzaniga, Michael S.

    2011-01-01

    Several studies report a right hemisphere advantage for visuospatial integration and a left hemisphere advantage for inferring conceptual knowledge from patterns of covariation. The present study examined hemispheric asymmetry in the implicit learning of new visual feature combinations. A split-brain patient and normal control participants viewed…

  18. Awake right hemisphere brain surgery.

    PubMed

    Hulou, M Maher; Cote, David J; Olubiyi, Olutayo I; Smith, Timothy R; Chiocca, E Antonio; Johnson, Mark D

    2015-12-01

    We report the indications and outcomes of awake right hemispheric brain surgery, as well as a rare patient with crossed aphasia. Awake craniotomies are often performed to protect eloquent cortex. We reviewed the medical records for 35 of 96 patients, in detail, who had awake right hemisphere brain operations. Intraoperative cortical mapping of motor and/or language function was performed in 29 of the 35 patients. A preoperative speech impairment and left hand dominance were the main indicators for awake right-sided craniotomies in patients with right hemisphere lesions. Four patients with lesion proximity to eloquent areas underwent awake craniotomies without cortical mapping. In addition, one patient had a broncho-pulmonary fistula, and another had a recent major cardiac procedure that precluded awake surgery. An eloquent cortex representation was identified in 14 patients (48.3%). Postoperatively, seven of 17 patients (41.1%) who presented with weakness, experienced improvements in their motor functions, 11 of 16 (68.7%) with seizures became seizure-free, and seven of nine (77.7%) with moderate to severe headaches and one of two with a visual field deficit improved significantly. There were also improvements in speech and language functions in all patients who presented with speech difficulties. A right sided awake craniotomy is an excellent option for left handed patients, or those with right sided cortical lesions that result in preoperative speech impairments. When combined with intraoperative cortical mapping, both speech and motor function can be well preserved.

  19. Hemispheric differences in the activation of perceptual information during sentence comprehension.

    PubMed

    Lincoln, Amy E; Long, Debra L; Baynes, Kathleen

    2007-01-28

    Previous research has suggested that perceptual information about objects is activated during sentence comprehension [Zwaan, R. A., Stanfield, R. A., & Yaxley, R. H. (2002). Language comprehenders mentally represent the shapes of objects. Psychological Science, 13(2), 168-171]. The goal in the current study was to examine the role of the two hemispheres in the activation of such information. Participants read sentences that conveyed information about the shape of an object (e.g., the egg was in the pan versus the egg was in the carton) and then received a picture of the object that was either consistent or inconsistent with the shape implied by the sentence (e.g., a fried egg versus a whole egg). In Experiment 1, pictures were presented briefly in either the left-visual field or the right-visual field. Participants showed a mismatch effect, slower responses when the picture was inconsistent with the shape of the object implied by the sentence than when it was consistent, but only when the pictures appeared in the right-visual field (left hemisphere). In Experiment 2, the sentences were revised such that the shape of the object was described explicitly. Participants showed a mismatch effect in both visual fields. These findings suggest that the right hemisphere activates shape information during sentence comprehension when a shape description is explicit, whereas the left hemisphere activates such information both when the shape is described explicitly and when it is implied.

  20. Geomorphological mapping of comet 67P/Churyumov-Gerasimenko's Southern hemisphere

    NASA Astrophysics Data System (ADS)

    Lee, Jui-Chi; Massironi, Matteo; Ip, Wing-Huen; Giacomini, Lorenza; Ferrari, Sabrina; Penasa, Luca; El-Maarry, Mohamed Ramy; Pajola, Maurizio; Lai, Ian-Lin; Lin, Zhong-Yi; Ferri, Francesca; Sierks, Holger; Barbieri, Cesare; Lamy, Philippe; Rodrigo, Rafael; Koschny, Detlef; Rickman, Hans; Keller, Horst Uwe; Agarwal, Jessica; A'Hearn, Michael F.; Barucci, Maria Antonella; Bertaux, Jean-Loup; Bertini, Ivano; Cremonese, Gabriele; Da Deppo, Vania; Davidsson, Björn; Debei, Stefano; De Cecco, Mariolino; Deller, Jakob; Fornasier, Sonia; Fulle, Marco; Groussin, Olivier; Gutiérrez, Pedro J.; Güttler, Carsten; Hofmann, Marc; Hviid, Stubbe F.; Jorda, Laurent; Knollenberg, Jörg; Kovacs, Gabor; Kramm, J.-Rainer; Kührt, Ekkehard; Küppers, Michael; Lara, Luisa M.; Lazzarin, Monica; Marzari, Francesco; Lopez Moreno, Josè J.; Naletto, Giampiero; Oklay, Nilda; Shi, Xian; Thomas, Nicolas; Tubiana, Cecilia; Vincent, Jean-Baptiste

    2016-11-01

    In 2015 May, the Southern hemisphere of comet 67P/Churyumov-Gerasimenko became visible by the OSIRIS cameras on-board the Rosetta spacecraft. The resolution was high enough to carry out a detailed analysis of the surface morphology, which is quite different from the Northern hemisphere. Previous works show that fine particle deposits are the most extensive geological unit in the Northern hemisphere. In contrast, the Southern hemisphere is dominated by outcropping consolidated terrain. In this work, we provide geomorphological maps of the Southern hemisphere with the distinction of both geological units and linear features. The geomorphological maps described in this study allow us to gain a better understanding of the processes shaping the comet nucleus and the distribution of primary structures such as fractures and strata.

  1. Morphology and Depth of Mars Northern Hemisphere Gullies

    NASA Astrophysics Data System (ADS)

    Gilmore, M. S.; Goldenson, N.

    2003-12-01

    Gullies, defined by having an alcove, channel and basin morphology have been interpreted to be evidence of melting ice in the recent era. Building on previous work (Gilmore and Phillips, Geology, Dec 2002) on southern hemisphere gullies, we have examined morphology and depth of gullies in the northern hemisphere of Mars. Forty-six gullies in 31 images have been identified in the northern hemisphere, compiled from a survey of the literature and some reconnaissance. Most of the gullies occur between 30N and 60; 8 of these landforms have been identified between 0 and 30N and are located at the summits of the Tharsis volcanoes. The gullies tend to form in regional clusters and are found within Amazonian and Hesperian aged geologic units, specifically materials of the Vastitas Borealis formation in both Utopia and Acidalia Planitae and flows from Elysium Mons. As with the southern hemisphere gullies, we find all northern hemisphere gullies to emanate from a particular layer that appears to be competent (often a cliff-former). We measured the depth of the gully heads below the local surface by registering MOC images and MOLA profiles in ISIS (MOC2MOLA script) supplied by the USGS. On average, northern hemisphere gullies lie 257m (range 86m to 555 m) below the local surface (error is approx. 20 m), consistent with previous measurements of southern hemisphere gullies (ibid). Omitting gullies on volcanoes, absolute depths range from approx. -5000 to -2100 m with respect to the MOLA datum; gullies on volcanoes span approx. 4700m - 20000m. The relationship of gullies with competent layers is consistent with a casual relationship, perhaps as an aquiclude. Models for gully formation must address the fact that the gullies are a near-surface phenomenon.

  2. Measurement of the B0 to pi l nu Form Factor Shape and Branching Fraction, and Determination of |Vub| with a Loose Neutrino Reconstruction Technique

    SciTech Connect

    Cote, D

    2006-09-26

    The authors report the results of a study of the exclusive charmless semileptonic B{sup 0} {yields} {pi}{sup -}{ell}{sup +}{nu} decay undertaken with approximately 227 million B{bar B} pairs collected at the {Upsilon}(4S) resonance with the BABAR detector. The analysis uses events in which the signal B mesons are reconstructed with a novel loose neutrino reconstruction technique. We obtain partial branching fractions in 12 bins of q{sup 2}, the {ell}{sup +}{nu} invariant mass squared, from which we extract the f{sup +}(q{sup 2}) form factor shape and the total branching fraction: {Beta}(B{sup 0} {yields} {pi}{sup -}{ell}{sup +}{nu}) = 1.44 {+-} 0.08{sub stat} {+-} 0.10{sub syst} x 10{sup -4}. Based on a recent theoretical calculation of the form factor, we find the magnitude of the CKM matrix element |V{sub ub}| to be (4.1 {+-} 0.2{sub stat} {+-} 0.2{sub syst{sub -0.4}{sup +0.6}}FF) x 10{sup -3}, where the last uncertainty is due to the normalization of the form factor.

  3. Priming Nouns and Verbs: Differential Influences of Semantic and Grammatical Cues in the Two Cerebral Hemispheres

    ERIC Educational Resources Information Center

    Arambel, Stella R.; Chiarello, Christine

    2006-01-01

    The current experiment investigated how sentential form-class expectancies influenced lexical-semantic priming within each hemisphere. Sentences were presented that led readers to expect a noun or a verb and the sentence-final target word was presented to one visual field/hemisphere for a lexical decision response. Noun and verb targets in the…

  4. The Integration of the Cerebral Hemispheres in Poetry and Mystic Texts.

    ERIC Educational Resources Information Center

    Cashford, Jules

    1979-01-01

    The author explores some of the implications of E. Rossi's hypothesis that "fine literature and poetry is essentially a form by which the words of the left hemisphere give voice to symbols and archetypal patterns of the right" (hemisphere). (Author/PHR)

  5. Remembering 1500 Pictures: The Right Hemisphere Remembers Better than the Left

    ERIC Educational Resources Information Center

    Laeng, Bruno; Overvoll, Morten; Ole Steinsvik, Oddmar

    2007-01-01

    We hypothesized that the right hemisphere would be superior to the left hemisphere in remembering having seen a specific picture before, given its superiority in perceptually encoding specific aspects of visual form. A large set of pictures (N=1500) of animals, human faces, artifacts, landscapes, and art paintings were shown for 2 s in central…

  6. [Vaccines: producers in countries of the Southern hemisphere].

    PubMed

    Bertrand, J J

    2007-08-01

    Vaccine producers in southern hemisphere countries now contribute significantly to global output. In 2006 southern hemisphere countries accounted for more than 10% of the total worldwide production with a progression approximately 70% greater than all producers combined in the two-year period between 2004 and 2006. Though difficult to measure, production in volume is higher due to lower prices practiced in most of these countries. For many years before the 1980s, production was scattered among numerous limited-scale companies. Most were founded at the initiative of governments striving to cover the needs of the population for essential vaccines. A number of institutions and private structures such as Institut Pasteur Production, Connaught Laboratories, and Institut Merieux have also set up production facilities. Today's producers can be divided into two categories, i.e., local producers that produce mainly monovalent vaccines and worldwide producers with strong R&D investment programs. Local producers are located mainly in large southern hemisphere countries such as China, India, Brazil, and Indonesia as well as in eastern countries. For the most dynamic companies, international development is focused on southern hemisphere countries excluding North America and Europe. With the support international organization such as WHO, UNICEF and GAVI, alliances are now being formed and networks are being organized in an effort to ensure reliable supplies of high quality vaccines at affordable prices in developing countries. The contribution of these producers will increase for the greater benefit of the people living in the southern hemisphere.

  7. Simulation of plasma filled hemispherical cavity as dielectric resonator antenna

    NASA Astrophysics Data System (ADS)

    Trenchev, G.; Kissóvski, Zh

    2016-10-01

    Plasma antennas are becoming an increasingly interesting research topic because of their uncommon characteristics. They are highly configurable, can be turned on and off rapidly, and exhibit lower thermal noise compared to metal antennas. In recent years, research has been conducted on cylindrical plasma columns sustained by DC, RF or microwave field, and their application as leaky wave antennas or as regular monopole antennas. Dielectric resonator antennas (DRA) with high dielectric permittivity are known for their small size and excellent operating characteristics for modern mobile communications (WiMAX, LTE). Hemispherical dielectric resonator antennas are characterized by simple shape, high radiation efficiency and wide bandwidth. Hemispherical DRA with a low density weakly ionized plasma as dielectric material will combine the positive features of plasma and dielectric antennas, and is particularly interesting, as antennas of this type have not been studied yet. The hemispherical plasma antenna is simulated with Ansoft HFSS in the microwave S-band. Obtained radiation pattern and bandwidth show the advantages of hemispherical plasma antennas for future communication technology.

  8. Shape memory polymers

    DOEpatents

    Wilson, Thomas S.; Bearinger, Jane P.

    2015-06-09

    New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxyl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

  9. Mitogenomics of southern hemisphere blue mussels (Bivalvia: Pteriomorphia): Insights into the evolutionary characteristics of the Mytilus edulis complex

    PubMed Central

    Gaitán-Espitia, Juan Diego; Quintero-Galvis, Julian F.; Mesas, Andres; D’Elía, Guillermo

    2016-01-01

    Marine blue mussels (Mytilus spp.) are widespread species that exhibit an antitropical distribution with five species occurring in the Northern Hemisphere (M. trossulus, M. edulis, M. galloprovincialis, M. californianus and M. coruscus) and three in the Southern Hemisphere (M. galloprovincialis, M. chilensis and M. platensis). Species limits in this group remain controversial, in particular for those forms that live in South America. Here we investigated structural characteristics of marine mussels mitogenomes, based on published F mtDNA sequences of Northern Hemisphere species and two newly sequenced South American genomes, one from the Atlantic M. platensis and another from the Pacific M. chilensis. These mitogenomes exhibited similar architecture to those of other genomes of Mytilus, including the presence of the Atp8 gene, which is missing in most of the other bivalves. Our evolutionary analysis of mitochondrial genes indicates that purifying selection is the predominant force shaping the evolution of the coding genes. Results of our phylogenetic analyses supported the monophyly of Pteriomorphia and fully resolved the phylogenetic relationships among its five orders. Finally, the low genetic divergence of specimens assigned to M. chilensis and M. platensis suggests that these South American marine mussels represent conspecific variants rather than distinct species. PMID:27241855

  10. Hemispheric specialization in quantification processes.

    PubMed

    Pasini, M; Tessari, A

    2001-01-01

    Three experiments were carried out to study hemispheric specialization for subitizing (the rapid enumeration of small patterns) and counting (the serial quantification process based on some formal principles). The experiments consist of numerosity identification of dot patterns presented in one visual field, with a tachistoscopic technique, or eye movements monitored through glasses, and comparison between centrally presented dot patterns and lateralized tachistoscopically presented digits. Our experiments show left visual field advantage in the identification and comparison tasks in the subitizing range, whereas right visual field advantage has been found in the comparison task for the counting range.

  11. PIIID-formed (Ti, O)/Ti, (Ti, N)/Ti and (Ti, O, N)/Ti coatings on NiTi shape memory alloy for medical applications.

    PubMed

    Sun, Tao; Wang, Lang-Ping; Wang, Min; Tong, Ho-Wang; Lu, William W

    2012-08-01

    (Ti, O)/Ti, (Ti, N)/Ti and (Ti, O, N)/Ti composite coatings were fabricated on NiTi shape memory alloy via plasma immersion ion implantation and deposition (PIIID). Surface morphology of samples was investigated using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Cross-sectional morphology indicated that the PIIID-formed coatings were dense and uniform. X-ray diffraction (XRD) was used to characterize the phase composition of samples. X-ray photoelectron spectroscopy (XPS) results showed that the surface of coated NiTi SMA samples was Ni-free. Nanoindentation measurements and pin-on-disc tests were carried out to evaluate mechanical properties and wear resistance of coated NiTi SMA, respectively. For the in vitro biological assessment of the composite coatings in terms of cell morphology and cell viability, osteoblast-like SaOS-2 cells and breast cancer MCF-7 cells were cultured on NiTi SMA samples, respectively. SaOS-2 cells attached and spread better on coated NiTi SMA. Viability of MCF-7 cells showed that the PIIID-formed composite coatings were noncytotoxic and coated samples were more biocompatible than uncoated samples.

  12. Large subcortical hemispheric infarctions. Presentation and prognosis.

    PubMed

    Levine, R L; Lagreze, H L; Dobkin, J A; Turski, P A

    1988-10-01

    A specific form of large subcortical hemispheric infarction on computed tomography was identified in 24 of 2198 (1%) stroke registry patients. Combined with 13 cases from earlier literature reports, a characteristic neurologic picture developed. Severe face plus arm plus leg weakness at onset (76%), corticallike features of aphasia and/or contralateral neglect (68%), and premonitory transient ischemic attacks (24%) were frequent. Twenty-two patients (59%) had large vessel arterial occlusive disease. Eight patients (22%) had primary embolic occlusion in the middle cerebral artery territory. During an average follow-up of 16 months, five patients (14%) suffered recurrent stroke or death. The clinical presentation and prognostic features of this distinct stroke subtype are described.

  13. Mechanism of secular increasing of mean gravity in Northern hemisphere and secular decreasing of mean gravity in Southern hemisphere

    NASA Astrophysics Data System (ADS)

    Barkin, Yu. V.; Ferrandiz, J. M.

    2009-04-01

    Mechanism. To present time the observant data in various geosciences more and more confidently testify for the benefit of existence of secular drift of the Earth core in the direction of North Pole. 1). So the superfluous mass of a displaced core relatively to elastic mantle, obviously, results in displacement of the centre of mass of the Earth with respect to basic system of coordinates on a surface of the Earth also in northern direction. Methods of a space geodesy let us confidently to determine drift of the centre of mass to the north with velocity about 0.5 - 1.0 cm/yr. The fundamental phenomenon of drift of the centre of mass and the core of the Earth has been predicted in 1995 (Barkin, 1995) at the analysis of secular change of the pear-shaped form of the Earth in present epoch (velocity of drift of the centre of mass of the Earth was appreciated in 1.8 +/-1.0 cm/yr in the direction of North Pole of the Earth). For an explanation of observably drift of the centre of mass at once the model of drift of the core was offered and the geodynamic model of forced relative displacements and wanderings of interacting shells of the Earth under action of a gravitational attraction of external celestial bodies (Barkin, 1996, 2002) has been developed. 2). The core makes slow secular drift and cyclic displacements. Predicted spectrum of oscillations of the centre of mass of the Earth and its core (Barkin, 2001) has received precise confirmation as a result of the Fourier analysis of temporal series for coordinates of a geocenter (Kaftan, Tatevian, 2003; Barkin, Vilke, 2004; Barkin, Lyubushin, Zotov, 2007). 3). The displaced core makes active all bouquet of natural processes in all shells of the Earth (including an atmosphere, ocean and internal shells), varying in the certain rhythms and styles the tension conditions of shells, their thermodynamic conditions etc. The core as though "conducts" by all planetary processes at once. From here take the origin such fundamental

  14. Dynamically tunable hemispherical electronic eye camera system with adjustable zoom capability

    PubMed Central

    Jung, Inhwa; Xiao, Jianliang; Malyarchuk, Viktor; Lu, Chaofeng; Li, Ming; Liu, Zhuangjian; Yoon, Jongseung; Huang, Yonggang; Rogers, John A.

    2011-01-01

    Imaging systems that exploit arrays of photodetectors in curvilinear layouts are attractive due to their ability to match the strongly nonplanar image surfaces (i.e., Petzval surfaces) that form with simple lenses, thereby creating new design options. Recent work has yielded significant progress in the realization of such “eyeball” cameras, including examples of fully functional silicon devices capable of collecting realistic images. Although these systems provide advantages compared to those with conventional, planar designs, their fixed detector curvature renders them incompatible with changes in the Petzval surface that accompany variable zoom achieved with simple lenses. This paper describes a class of digital imaging device that overcomes this limitation, through the use of photodetector arrays on thin elastomeric membranes, capable of reversible deformation into hemispherical shapes with radii of curvature that can be adjusted dynamically, via hydraulics. Combining this type of detector with a similarly tunable, fluidic plano-convex lens yields a hemispherical camera with variable zoom and excellent imaging characteristics. Systematic experimental and theoretical studies of the mechanics and optics reveal all underlying principles of operation. This type of technology could be useful for night-vision surveillance, endoscopic imaging, and other areas that require compact cameras with simple zoom optics and wide-angle fields of view. PMID:21245356

  15. Dynamically tunable hemispherical electronic eye camera system with adjustable zoom capability.

    PubMed

    Jung, Inhwa; Xiao, Jianliang; Malyarchuk, Viktor; Lu, Chaofeng; Li, Ming; Liu, Zhuangjian; Yoon, Jongseung; Huang, Yonggang; Rogers, John A

    2011-02-01

    Imaging systems that exploit arrays of photodetectors in curvilinear layouts are attractive due to their ability to match the strongly nonplanar image surfaces (i.e., Petzval surfaces) that form with simple lenses, thereby creating new design options. Recent work has yielded significant progress in the realization of such "eyeball" cameras, including examples of fully functional silicon devices capable of collecting realistic images. Although these systems provide advantages compared to those with conventional, planar designs, their fixed detector curvature renders them incompatible with changes in the Petzval surface that accompany variable zoom achieved with simple lenses. This paper describes a class of digital imaging device that overcomes this limitation, through the use of photodetector arrays on thin elastomeric membranes, capable of reversible deformation into hemispherical shapes with radii of curvature that can be adjusted dynamically, via hydraulics. Combining this type of detector with a similarly tunable, fluidic plano-convex lens yields a hemispherical camera with variable zoom and excellent imaging characteristics. Systematic experimental and theoretical studies of the mechanics and optics reveal all underlying principles of operation. This type of technology could be useful for night-vision surveillance, endoscopic imaging, and other areas that require compact cameras with simple zoom optics and wide-angle fields of view.

  16. Intra-hemispheric intrinsic connectivity asymmetry and its relationships with handedness and language Lateralization.

    PubMed

    Joliot, M; Tzourio-Mazoyer, N; Mazoyer, B

    2016-12-01

    significant positive linear relationship between the HICAs and HFLI indices, with an effect of handedness on the intercept but not on the slope of this relationship. These findings demonstrate that handedness and hemispheric dominance for language are significantly but independently associated with the asymmetry of intra-hemispheric intrinsic connectivity. These findings suggest that asymmetry in intra-hemispheric connectivity is a variable phenotype shaped in part by hemispheric lateralization for language, but possibly also depending on other lateralized functions.

  17. A hemispherical dynamo on Mars?

    NASA Astrophysics Data System (ADS)

    Dietrich, Wieland; Wicht, Johannes; Hori, Kumiko

    2015-04-01

    Numerous threedimensional MHD models investigated the induction of planetary magnetic fields under the influence of a laterally varying heat flux through the core mantle boundary (CMB). E.g. for the dynamo process in ancient Mars, a planetary scale CMB heat flux anomaly (Y10) reduces the rate of heat escaping the core in the north and increases it in the south, what concentrates the convection and induction into a single hemisphere. On the expense of rapid polarity inversions, it then seemed possible to increase the equatorial asymmetry far enough to correspond to the hemisphericity of the Martian crustal magnetisation. Within this study we parametrise horizontal extent, latitudinal position and amplitude of the anomaly in a rather comprehensive parameter study. Global flow symmetry properties are justified and used to quantify the influence of the heat flux anomalies and the action of the magnetic field. Our results suggest, that only rather large scale and strong amplitude anomalies are sufficient to induce magnetic fields matching the equatorial asymmetry of the crustal magnetisation pattern. Further all geometrically corresponding dynamo models show the problematic rapid polarity inversions which allow a strong and unidirectional magnetisation only when the crustal built-up time is on the order of the magnetic diffusion time (several kyrs). In summary, our results suggest that a single mantle hot spot positionend anywhere at the CMB will affect the core dynamics significantly only if its horizontal extent is on the order of the radius of the outer core. For Mars it seemes quite plausible, that the crustal magnetisation pattern was strongly influenced by post-dynamo demagnetisation processes rather than being magnetised by a geometrically corresponding internal dynamo field.

  18. Homotopic Language Reorganization in the Right Hemisphere after Early Left Hemisphere Injury

    ERIC Educational Resources Information Center

    Tivarus, Madalina E.; Starling, Sarah J.; Newport, Elissa L.; Langfitt, John T.

    2012-01-01

    To determine the areas involved in reorganization of language to the right hemisphere after early left hemisphere injury, we compared fMRI activation patterns during four production and comprehension tasks in post-surgical epilepsy patients with either left (LH) or right hemisphere (RH) speech dominance (determined by Wada testing) and healthy…

  19. Hemispheric inference priming during comprehension of conversations and narratives.

    PubMed

    Powers, Chivon; Bencic, Rachel; Horton, William S; Beeman, Mark

    2012-09-01

    In this study we examined asymmetric semantic activation patterns as people listened to conversations and narratives that promoted causal inferences. Based on the hypothesis that understanding the unique features of conversational input may benefit from or require a modified pattern of conceptual activation during conversation, we compared semantic priming in both hemispheres for inferences embedded in conversations and in narratives. Participants named inference-related target words or unrelated words presented to the left visual field-right hemisphere (lvf-RH) or to the right visual field-left hemisphere (rvf-LH) at critical coherence points that required an inference in order to correctly understand an utterance in the context of the conversation or narrative. Fifty-seven undergraduates listened to 36 conversations or narratives and were tested at 100 target inference points. During narrative comprehension, inference-related priming was reliable and equally strong in both hemispheres. In contrast, during conversation comprehension, inference-related priming was only reliable for target words presented to lvf-RH. This work demonstrates that priming for inference-related concepts can be measured with input in conversational form and suggests the language processing style of the RH is advantageous for comprehending conversation.

  20. Interaction of cerebral hemispheres and artistic thinking

    NASA Astrophysics Data System (ADS)

    Nikolaenko, Nikolay N.

    1998-07-01

    Study of drawings by patients with local lesions of the right or left hemisphere allows to understand how artistic thinking is supported by brain structures. The role of the right hemisphere is significant at the early stage of creative process. The right hemisphere is a generator of nonverbal visuo-spatial thinking. It operates with blurred nonverbal images and arrange them in a visual space. With the help of iconic signs the right hemisphere reflects the world and creates perceptive visual standards which are stored in the long-term right hemisphere memory. The image, which appeared in the `inner' space, should be transferred into a principally different language, i.e. a left hemispheric sign language. This language operates with a number of discrete units, logical succession and learned grammar rules. This process can be explained by activation (information) transfer from the right hemisphere to the left one. Thus, natural and spontaneous creative process, which is finished by a conscious effort, can be understood as an activation impulse transfer from the right hemisphere to the left one and back.

  1. Fantasy and the Brain's Right Hemisphere.

    ERIC Educational Resources Information Center

    Shuman, R. Baird

    While the left hemisphere of the brain is responsible for logical and verbal activity, the right brain is the center of much of human feeling and emotion. Its vision is holistic rather than segmented or compartmentalized. Although schools today are geared almost exclusively to training the brain's left hemisphere, fantasy literature can provide…

  2. Hemispheric Dominance of Native American Indian Students.

    ERIC Educational Resources Information Center

    Stellern, John; And Others

    1986-01-01

    Examines language and spatial lateralization of 49 elementary American Indian students using a cognitive-manual dual task model and psychoeducational assessment techniques. All students were found to be left-hemisphere dominant for language and some were lateralized to the left hemisphere for spatial function. Contradicts evidence of right-brain…

  3. Robust Controller Design for Hemispherical Resonator Gyroscope

    DTIC Science & Technology

    2011-11-01

    f v Figure 1. Operating principle of HRG Robust Controller Design for Hemispherical Resonator Gyroscope Chul Hyun1), Byung ...Petersburg, Russia.: 26-34 4) Chul Hyun. 2011. Design of Robust Digital Controller for Hemispherical Resonator Gyroscopes, Ph.D. dissertation, Seoul

  4. The Cost of Action Miscues: Hemispheric Asymmetries

    ERIC Educational Resources Information Center

    Shenal, Brian V.; Hinze, Stephan; Heilman, Kenneth M.

    2012-01-01

    Adaptive behaviors require preparation and when necessary inhibition or alteration of actions. The right hemisphere has been posited to be dominant for preparatory motor activation. This experiment was designed to learn if there are hemispheric asymmetries in the control of altered plans of actions. Cues, both valid and invalid, which indicate the…

  5. Measurements of right / left hemisphere activation using functional near-infrared spectroscopy during incongruent Stroop test.

    PubMed

    Hiroyasu, Tomoyuki; Fukuhara, Michihiro; Yokouchi, Hisatake; Miki, Mitsunori; Yoshimi, Masato

    2011-01-01

    The human brain automatically processes information at multiple sites when recognizing various types of information at the same time, such as color, shape, etc. Cognitive conflict may occur when conflicting information is recognized at the same time. Functional near-infrared spectroscopy (fNIRS) is often used to examine the brain activity associated with this phenomenon. To examine activation of the visual system, we measured brain activity in the right / left hemispheres during cognitive conflict in the Stroop test. Consistent with the results reported previously by Ehlis, the brain activity in the near inferior-frontal gyrus of the left hemisphere was increased during the incongruent task. The brain activity also increased in the near inferior-frontal gyrus of the right hemisphere during the incongruent task. These results indicated that fNIRS can be used to detect brain activity in the inferior-frontal gyrus of the right / left hemispheres during the Stroop test.

  6. Hemispheric lateralization of semantic feature distinctiveness.

    PubMed

    Reilly, M; Machado, N; Blumstein, S E

    2015-08-01

    Recent models of semantic memory propose that the semantic representation of concepts is based, in part, on a network of features. In this view, a feature that is distinctive for an object (a zebra has stripes) is processed differently from a feature that is shared across many objects (a zebra has four legs). The goal of this paper is to determine whether there are hemispheric differences in such processing. In a feature verification task, participants responded 'yes' or 'no' following concepts which were presented to a single visual field (left or right) paired with a shared or distinctive feature. Both hemispheres showed faster reaction times to shared features than to distinctive features, although right hemisphere responses were significantly slower overall and particularly in the processing of distinctive features. These findings support models of semantic processing in which the dominant left hemisphere more efficiently performs highly discriminating 'fine' encoding, in contrast to the right hemisphere which performs less discriminating 'coarse' encoding.

  7. UV Observations of Hemispheric Asymmetry

    NASA Astrophysics Data System (ADS)

    Schaefer, R. K.; Paxton, L. J.; Wolven, B. C.; Zhang, Y.; Romeo, G.

    2015-12-01

    Asymmetry in the auroral patterns can be an important diagnostic for understanding the dynamics of solar wind interaction with the magnetosphere-ionosphere-thermosphere system (e.g., Newel and Meng, 1998; Fillingrim et al., 2005). Molecular nitrogen emission in the UV Lyman-Birge-Hopfield bands can be used to determine energy flux and electron mean energy (Sotirelis, et al, 2013) and thereby Hall and Pederson integrated conductances (Gjerloev, et al., 2014). UV imagery provided by the 4 SSUSI instruments on the Defense Meteorological Satellite Program (DMSP) F16-F19 spacecraft provide two dimensional maps of this emission at different local times. Often there are near simultaneous observations of both poles by some combination of the satellites. (see figure 1) The SSUSI auroral data products are well suited to this study, as they have the following features.: - dayglow has been subtracted on dayside aurora - electron energy flux and mean energy are pre-calculated - individual arcs have been identified through image processing. In order to intercompare data from multiple satellites, we must first ensure that the instrument calibrations are consistent. In this work we show that the instruments are consistently calibrated, and that results generated from the SSUSI data products can be trusted. Several examples of storm time asymmetries captured by the SSUSI instruments will be discussed. Fillingim, M. O., G. K. Parks, H. U. Frey, T. J. Immel, and S. B. Mende (2005), Hemispheric asymmetry of the afternoon electron aurora, Geophys. Res. Lett., 32, L03113, doi:10.1029/2004GL021635. Gjerloev, J., Schaefer, R., Paxton, L, and Zhang, Y. (2014), A comprehensive empirical model of the ionospheric conductivity derived from SSUSI/GUVI, SuperMAG and SuperDARN data, SM51G-4339, Fall 2014 AGU meeting, San Francisco. Newell, P. T., and C.-I. Meng (1988), Hemispherical asymmetry in cusp precipitation near solstices, J. Geophys. Res., 93(A4), 2643-2648, doi:10.1029/JA093iA04p02643

  8. HEMISPHERIC CENTER FOR ENVIRONMENTAL TECHNOLOGY

    SciTech Connect

    M.A. Ebadian

    1999-10-31

    The Deactivation and Decommissioning (D&D) Technology Assessment Program (TAP) was developed to provide detailed, comparable data for environmental technologies and to disseminate this data to D&D professionals in a manner that will facilitate the review and selection of technologies to perform decontamination and decommissioning. The objectives for this project include the following: Determine technology needs through review of the Site Technology Coordination Group (STCG) information and other applicable websites and needs databases; Perform a detailed review of industries that perform similar activities as those required in D&D operations to identify additional technologies; Define the technology assessment program for characterization and waste management problem sets; Define the data management program for characterization, dismantlement, and waste management problem sets; Evaluate baseline and innovative technologies under standard test conditions at Florida International University's Hemispheric Center for Environmental Technology (FIU-HCET) and other locations and collect data in the areas of performance, cost, health and safety, operations and maintenance, and primary and secondary waste generation; Continue to locate, verify, and incorporate technology performance data from other sources into the multimedia information system; and Develop the conceptual design for a dismantlement technology decision analysis tool for dismantlement technologies.

  9. Hemispheric Asymmetries in Substorm Recovery Time Scales

    NASA Technical Reports Server (NTRS)

    Fillingim, M. O.; Chua, D H.; Germany, G. A.; Spann, James F.

    2009-01-01

    Previous statistical observations have shown that the recovery time scales of substorms occurring in the winter and near equinox (when the nighttime auroral zone was in darkness) are roughly twice as long as the recovery time scales for substorms occurring in the summer (when the nighttime auroral region was sunlit). This suggests that auroral substorms in the northern and southern hemispheres develop asymmetrically during solstice conditions with substorms lasting longer in the winter (dark) hemisphere than in the summer (sunlit) hemisphere. Additionally, this implies that more energy is deposited by electron precipitation in the winter hemisphere than in the summer one during substorms. This result, coupled with previous observations that have shown that auroral activity is more common when the ionosphere is in darkness and is suppressed when the ionosphere is in daylight, strongly suggests that the ionospheric conductivity plays an important role governing how magnetospheric energy is transferred to the ionosphere during substorms. Therefore, the ionosphere itself may dictate how much energy it will accept from the magnetosphere during substorms rather than this being an externally imposed quantity. Here, we extend our earlier work by statistically analyzing the recovery time scales for a large number of substorms observed in the conjugate hemispheres simultaneously by two orbiting global auroral imagers: Polar UVI and IMAGE FUV. Our current results are consistent with previous observations. The recovery time scales are observed to be longer in the winter (dark) hemisphere while the auroral activity has a shorter duration in the summer (sunlit) hemisphere. This leads to an asymmetric energy input from the magnetosphere to the ionosphere with more energy being deposited in the winter hemisphere than in the summer hemisphere.

  10. Remote canopy hemispherical image collection system

    NASA Astrophysics Data System (ADS)

    Wan, Xuefen; Liu, Bingyu; Yang, Yi; Han, Fang; Cui, Jian

    2016-11-01

    Canopies are major part of plant photosynthesis and have distinct architectural elements such as tree crowns, whorls, branches, shoots, etc. By measuring canopy structural parameters, the solar radiation interception, photosynthesis effects and the spatio-temporal distribution of solar radiation under the canopy can be evaluated. Among canopy structure parameters, Leaf Area Index (LAI) is the key one. Leaf area index is a crucial variable in agronomic and environmental studies, because of its importance for estimating the amount of radiation intercepted by the canopy and the crop water requirements. The LAI can be achieved by hemispheric images which are obtained below the canopy with high accuracy and effectiveness. But existing hemispheric images canopy-LAI measurement technique is based on digital SLR camera with a fisheye lens. Users need to collect hemispheric image manually. The SLR camera with fisheye lens is not suit for long-term canopy-LAI outdoor measurement too. And the high cost of SLR limits its capacity. In recent years, with the development of embedded system and image processing technology, low cost remote canopy hemispheric image acquisition technology is becoming possible. In this paper, we present a remote hemispheric canopy image acquisition system with in-field/host configuration. In-field node based on imbed platform, low cost image sensor and fisheye lens is designed to achieve hemispherical image of plant canopy at distance with low cost. Solar radiation and temperature/humidity data, which are important for evaluating image data validation, are obtained for invalid hemispherical image elimination and node maintenance too. Host computer interacts with in-field node by 3G network. The hemispherical image calibration and super resolution are used to improve image quality in host computer. Results show that the remote canopy image collection system can make low cost remote canopy image acquisition for LAI effectively. It will be a potential

  11. Compact Autonomous Hemispheric Vision System

    NASA Technical Reports Server (NTRS)

    Pingree, Paula J.; Cunningham, Thomas J.; Werne, Thomas A.; Eastwood, Michael L.; Walch, Marc J.; Staehle, Robert L.

    2012-01-01

    Solar System Exploration camera implementations to date have involved either single cameras with wide field-of-view (FOV) and consequently coarser spatial resolution, cameras on a movable mast, or single cameras necessitating rotation of the host vehicle to afford visibility outside a relatively narrow FOV. These cameras require detailed commanding from the ground or separate onboard computers to operate properly, and are incapable of making decisions based on image content that control pointing and downlink strategy. For color, a filter wheel having selectable positions was often added, which added moving parts, size, mass, power, and reduced reliability. A system was developed based on a general-purpose miniature visible-light camera using advanced CMOS (complementary metal oxide semiconductor) imager technology. The baseline camera has a 92 FOV and six cameras are arranged in an angled-up carousel fashion, with FOV overlaps such that the system has a 360 FOV (azimuth). A seventh camera, also with a FOV of 92 , is installed normal to the plane of the other 6 cameras giving the system a > 90 FOV in elevation and completing the hemispheric vision system. A central unit houses the common electronics box (CEB) controlling the system (power conversion, data processing, memory, and control software). Stereo is achieved by adding a second system on a baseline, and color is achieved by stacking two more systems (for a total of three, each system equipped with its own filter.) Two connectors on the bottom of the CEB provide a connection to a carrier (rover, spacecraft, balloon, etc.) for telemetry, commands, and power. This system has no moving parts. The system's onboard software (SW) supports autonomous operations such as pattern recognition and tracking.

  12. Modeling Hemispheric Detonation Experiments in 2-Dimensions

    SciTech Connect

    Howard, W M; Fried, L E; Vitello, P A; Druce, R L; Phillips, D; Lee, R; Mudge, S; Roeske, F

    2006-06-22

    Experiments have been performed with LX-17 (92.5% TATB and 7.5% Kel-F 800 binder) to study scaling of detonation waves using a dimensional scaling in a hemispherical divergent geometry. We model these experiments using an arbitrary Lagrange-Eulerian (ALE3D) hydrodynamics code, with reactive flow models based on the thermo-chemical code, Cheetah. The thermo-chemical code Cheetah provides a pressure-dependent kinetic rate law, along with an equation of state based on exponential-6 fluid potentials for individual detonation product species, calibrated to high pressures ({approx} few Mbars) and high temperatures (20000K). The parameters for these potentials are fit to a wide variety of experimental data, including shock, compression and sound speed data. For the un-reacted high explosive equation of state we use a modified Murnaghan form. We model the detonator (including the flyer plate) and initiation system in detail. The detonator is composed of LX-16, for which we use a program burn model. Steinberg-Guinan models5 are used for the metal components of the detonator. The booster and high explosive are LX-10 and LX-17, respectively. For both the LX-10 and LX-17, we use a pressure dependent rate law, coupled with a chemical equilibrium equation of state based on Cheetah. For LX-17, the kinetic model includes carbon clustering on the nanometer size scale.

  13. Fast discharge in a plasma gun with hemispherical insulator

    SciTech Connect

    Antsiferov, P. S.; Dorokhin, L. A.; Sidelnikov, Yu. V.; Koshelev, K. N.

    2009-05-15

    A method of creation of hot dense plasma is proposed. It is based on cumulation of a shockwave, which originates on a hemispherical surface of insulator of plasma gun. The results of first experiments are presented. The shock wave is driven by fast electrical discharge (dI/dt>10{sup 12} A/s). The inductive storage with semiconductor opening switch is used as a current driver. Time resolved pin-hole images and vacuum ultraviolet (vuv) spectra are studied. Shockwaves from hemispherical insulator with 4 mm radius create plasma with a form of column about 1 mm diameter and 3-4 mm length. vuv spectra contain the lines of Ar ions that corresponds to the electron temperature about 20 eV. Possible practical application is discussed.

  14. Volcanism in the cratered terrain hemisphere of Mars

    NASA Technical Reports Server (NTRS)

    Greeley, R.; Spudis, P. D.

    1978-01-01

    Four kinds of Martian volcanoes and their prevalences in the cratered terrain hemisphere (generally the southern hemisphere) are described. Patera, which are large low-profile volcanic structures, appear to be either older shield volcanoes or a unique type of volcano. 'Plains' volcanics represent low-volume eruptions that formed cones, low shields, and other small-scale structures. Flood volcanics are produced by high-volume eruptions, post-date the older and more degraded plateau plains, and occur mostly as basin-fill materials. Plateau plains, the Martian intercrater plains, contain many wrinkle ridges and floor-fractured craters. It is suggested that volcanic processes as well as erosional processes have been important in obliterating small Martian craters and that volcanic products may constitute a significant fraction (up to 44%) of the surface rocks in the cratered terrain

  15. A free-standing, sheet-shaped, "hydrophobic" biomaterial containing polymeric micelles formed from poly(ethylene glycol)-poly(lactic acid) block copolymer for possible incorporation/release of "hydrophilic" compounds.

    PubMed

    Moroishi, Hitomi; Yoshida, Chikara; Murakami, Yoshihiko

    2013-02-01

    Sheet-shaped materials with a large contact area relative to the drug targeting site lead to advantages over conventional particle-shaped drug carriers and have several advantages for their biomedical applications. The present study proposes a methodology for preparing a novel sheet-shaped "hydrophobic" and biocompatible biomaterial in which polymeric micelles are uniformly dispersed for the incorporation of "hydrophilic" compounds into the sheet. The methoxy-terminated poly(ethylene glycol)-block-poly(lactic acid) block copolymer (CH(3)O-PEG-b-PLA) was successfully synthesized by means of the anionic ring-opening polymerization of both ethylene oxide and dl-lactide. CH(3)O-PEG-b-PLA was self-assembled and formed stable micelle-like w/o emulsion with a hydrophilic inner core in organic solvents. A sheet-shaped material containing a hydrophilic inner space for incorporating hydrophilic compounds was obtained by spin-coating both the micelle solution and a sheet-forming polymer. Fluorescent images of the sheet proved that polymeric micelles providing hydrophilic spaces were uniformly dispersed in the hydrophobic sheet. The facile technique presented in this paper can be a tool for fabricating sheet-shaped biomaterials that have a hydrophilic inner core and, consequently, that are suitable for the sustained release of hydrophilic compounds.

  16. Huge Filament Rises From Sun's Northern Hemisphere

    NASA Video Gallery

    On August 1, 2010 following a C3-class solar flare from sunspot 1092, an enormous magnetic filament stretching across the sun's northern hemisphere erupted. This 304 angstrom video shows that filam...

  17. Grinding tool for making hemispherical bores in hard materials

    DOEpatents

    Duran, E.L.

    1985-04-03

    A grinding tool for forming hemispherical bores in hard materials such as boron carbide. The tool comprises a hemicircular grinding bit, formed of a metal bond diamond matrix, which is mounted transversely on one end of a tubular tool shaft. The bit includes a spherically curved outer edge surface which is the active grinding surface of the tool. Two coolant fluid ports on opposite sides of the bit enable introduction of coolant fluid through the bore of the tool shaft so as to be emitted adjacent the opposite sides of the grinding bit, thereby providing optimum cooling of both the workpiece and the bit.

  18. The Effects of Multiple Script Priming on Word Recognition by the Two Cerebral Hemispheres: Implications for Discourse Processing

    ERIC Educational Resources Information Center

    Faust, Miriam; Barak, Ofra; Chiarello, Christine

    2006-01-01

    The present study examined left (LH) and right (RH) hemisphere involvement in discourse processing by testing the ability of each hemisphere to use world knowledge in the form of script contexts for word recognition. Participants made lexical decisions to laterally presented target words preceded by centrally presented script primes (four…

  19. Hemispheric differences in solar wind - magnetosphere interactions

    NASA Astrophysics Data System (ADS)

    Reistad, J. P.; Ostgaard, N.; Laundal, K.; Snekvik, K.; Tenfjord, P.; Oksavik, K.

    2014-12-01

    Although the aurora to a large degree behave similar in the two hemispheres, recent simultaneous observations of the global aurora from space have revealed that sometimes rather large intensity and location asymmetries are present in the global aurora. From event studies using e.g. conjugate imaging, multiple mechanisms have been proposed to be responsible for the asymmetric aurora. However, we know very little about their general importance. We have investigated the general importance of an asymmetric solar wind dynamo. It has been suggested that the radial component of the IMF can modify the energy conversion between the solar wind and magnetosphere differently in the two hemispheres in a general sense. By looking at the global aurora using IMAGE WIC during carefully selected events minimally contaminated by other mechanisms affecting the two hemispheres differently, we find that the dusk side aurora depend oppositely on the radial IMF direction in the two hemispheres. These results are consistent with an asymmetric solar wind dynamo where the hemispheric preference is controlled by the radial IMF. This is the first study indicating the importance of the asymmetric solar wind dynamo in a general sense. A different mechanism, the asymmetric loading of magnetic flux during IMF By conditions is also expected to account for North-South asymmetries in the nightside global aurora. This will be investigated using a similar approach to establish the general importance of of this IMF By mechanism on the global aurora in the two hemispheres.

  20. Hemispherical map for the human brain cortex

    NASA Astrophysics Data System (ADS)

    Tosun, Duygu; Prince, Jerry L.

    2001-07-01

    Understanding the function of the human brain cortex is a primary goal in human brain mapping. Methods to unfold and flatten the cortical surface for visualization and measurement have been described in previous literature; but comparison across multiple subjects is still difficult because of the lack of a standard mapping technique. We describe a new approach that maps each hemisphere of the cortex to a portion of a sphere in a standard way, making comparison of anatomy and function across different subjects possible. Starting with a three-dimensional magnetic resonance image of the brain, the cortex is segmented and represented as a triangle mesh. Defining a cut around the corpus collosum identifies the left and right hemispheres. Together, the two hemispheres are mapped to the complex plane using a conformal mapping technique. A Mobius transformation, which is conformal, is used to transform the points on the complex plane so that a projective transformation maps each brain hemisphere onto a spherical segment comprising a sphere with a cap removed. We determined the best size of the spherical cap by minimizing the relative area distortion between hemispherical maps and original cortical surfaces. The relative area distortion between the hemispherical maps and the original cortical surfaces for fifteen human brains is analyzed.

  1. Differential hemispheric modulation of preparatory attention.

    PubMed

    Fernández, Laura Gabriela; Siéroff, Eric

    2014-06-01

    Preparatory attention (PA) is the ability to allocate attention to a stimulus prior to its occurrence and is a crucial component of attentional control. We investigated the role of brain hemispheres in PA using an experimental test in which normal participants responded to a target that could appear in the right or the left visual fields, thus projecting to the left or the right hemispheres, while ignoring a central distractor that could appear in the preparatory phase preceding the target. This experimental test measures the ability of participants to modulate PA directed to a target location when the probability of a distractor occurrence varies across three blocks of trials (0%, 33%, 67%). The competition between distractors and target for PA should produce slower response times when the probability of distractors is high. Three experiments were conducted varying the temporal predictability of the target occurrence within a trial (high predictability in Experiments 1 and 3, and low predictability in Experiment 2), and the task used (location in Experiments 1 and 2, and detection in Experiment 3). We found that the modulation of PA by the expected probability of events was different in each visual field/hemisphere. Whereas the left hemisphere PA was influenced by the mere probability of events in each block of trials, the right hemisphere PA was mainly influenced by events with high temporal predictability. These results suggest that each hemisphere uses a different strategy to modulate PA when directed to a target location at the perceptual level of visual processing.

  2. Northern Hemisphere forcing of Southern Hemisphere climate during the last deglaciation.

    PubMed

    He, Feng; Shakun, Jeremy D; Clark, Peter U; Carlson, Anders E; Liu, Zhengyu; Otto-Bliesner, Bette L; Kutzbach, John E

    2013-02-07

    According to the Milankovitch theory, changes in summer insolation in the high-latitude Northern Hemisphere caused glacial cycles through their impact on ice-sheet mass balance. Statistical analyses of long climate records supported this theory, but they also posed a substantial challenge by showing that changes in Southern Hemisphere climate were in phase with or led those in the north. Although an orbitally forced Northern Hemisphere signal may have been transmitted to the Southern Hemisphere, insolation forcing can also directly influence local Southern Hemisphere climate, potentially intensified by sea-ice feedback, suggesting that the hemispheres may have responded independently to different aspects of orbital forcing. Signal processing of climate records cannot distinguish between these conditions, however, because the proposed insolation forcings share essentially identical variability. Here we use transient simulations with a coupled atmosphere-ocean general circulation model to identify the impacts of forcing from changes in orbits, atmospheric CO(2) concentration, ice sheets and the Atlantic meridional overturning circulation (AMOC) on hemispheric temperatures during the first half of the last deglaciation (22-14.3 kyr BP). Although based on a single model, our transient simulation with only orbital changes supports the Milankovitch theory in showing that the last deglaciation was initiated by rising insolation during spring and summer in the mid-latitude to high-latitude Northern Hemisphere and by terrestrial snow-albedo feedback. The simulation with all forcings best reproduces the timing and magnitude of surface temperature evolution in the Southern Hemisphere in deglacial proxy records. AMOC changes associated with an orbitally induced retreat of Northern Hemisphere ice sheets is the most plausible explanation for the early Southern Hemisphere deglacial warming and its lead over Northern Hemisphere temperature; the ensuing rise in atmospheric CO(2

  3. Buried mass anomalies along the hemispheric dichotomy in eastern Mars: Implications for the origin and evolution of the dichotomy

    NASA Astrophysics Data System (ADS)

    Kiefer, Walter S.

    2005-11-01

    Gravity observations indicate the presence of buried, high-density material along the hemispheric dichotomy in eastern Mars. This material is unrelated to present-day topography and is probably the result of localized thinning of the crust. This thinning may be the result of an epoch of edge-driven convection that occurred shortly after the dichotomy formed. Initiation of edge-driven convection requires that lateral variations in lithospheric structure be created on a timescale that is shorter than the conductive cooling time for the lithosphere, a few tens of million years at most. This timescale cannot be achieved if the dichotomy boundary is created solely by large-scale convective flow. Formation or modification of the boundary by large impact basins such as Utopia can create the required lithospheric structure in a geologic instant. This suggests that large impacts were important in shaping the dichotomy, at least on a regional scale.

  4. A hemispherical electronic eye camera based on compressible silicon optoelectronics.

    PubMed

    Ko, Heung Cho; Stoykovich, Mark P; Song, Jizhou; Malyarchuk, Viktor; Choi, Won Mook; Yu, Chang-Jae; Geddes, Joseph B; Xiao, Jianliang; Wang, Shuodao; Huang, Yonggang; Rogers, John A

    2008-08-07

    The human eye is a remarkable imaging device, with many attractive design features. Prominent among these is a hemispherical detector geometry, similar to that found in many other biological systems, that enables a wide field of view and low aberrations with simple, few-component imaging optics. This type of configuration is extremely difficult to achieve using established optoelectronics technologies, owing to the intrinsically planar nature of the patterning, deposition, etching, materials growth and doping methods that exist for fabricating such systems. Here we report strategies that avoid these limitations, and implement them to yield high-performance, hemispherical electronic eye cameras based on single-crystalline silicon. The approach uses wafer-scale optoelectronics formed in unusual, two-dimensionally compressible configurations and elastomeric transfer elements capable of transforming the planar layouts in which the systems are initially fabricated into hemispherical geometries for their final implementation. In a general sense, these methods, taken together with our theoretical analyses of their associated mechanics, provide practical routes for integrating well-developed planar device technologies onto the surfaces of complex curvilinear objects, suitable for diverse applications that cannot be addressed by conventional means.

  5. Music Appreciation and Hemisphere Orientation: Visual versus Verbal Involvement.

    ERIC Educational Resources Information Center

    Zalanowski, Annette H.

    1990-01-01

    Analyzes effect of brain hemisphere orientation on music appreciation. Reports results from 36 left-hemisphere and 36 right-hemisphere undergraduates who responded to a musical selection verbally or visually. Finds right-hemisphere students show greater appreciation, measured by attention, understanding, and enjoyment scores. Discusses…

  6. Hemispheric Specialization and Cognitive Development: Implications for Mathematics Education

    ERIC Educational Resources Information Center

    Wheatley, Grayson, H.; And Others

    1978-01-01

    Evidence is presented for the theory that the two brain hemispheres process stimuli differently: the left hemisphere is specialized for logico-analytic tasks and the right hemisphere for visuo-spatial tasks. They contend that cognitive ability is related to the development of hemispheric asymmetry and present implications for mathematics education…

  7. Hemispheric asymmetries in cortical and subcortical anatomy.

    PubMed

    Kang, Xiaojian; Herron, Timothy J; Ettlinger, Marc; Woods, David L

    2015-01-01

    Previous research studies have reported many hemispherical asymmetries in cortical and subcortical anatomy, but only a subset of findings is consistent across studies. Here, we used improved Freesurfer-based automated methods to analyse the properties of the cortex and seven subcortical structures in 138 young adult subjects. Male and female subjects showed similar hemispheric asymmetries in gyral and sulcal structures, with many areas associated with language processing enlarged in the left hemisphere (LH) and a number of areas associated with visuospatial processing enlarged in the right hemisphere (RH). In addition, we found greater (non-directional) cortical asymmetries in subjects with larger brains. Asymmetries in subcortical structures included larger LH volumes of thalamus, putamen and globus pallidus and larger RH volumes of the cerebellum and the amygdala. We also found significant correlations between the subcortical structural volumes, particularly of the thalamus and cerebellum, with cortical area. These results help to resolve some of the inconsistencies in previous studies of hemispheric asymmetries in brain anatomy.

  8. Hemispheric lateralization of semantic feature distinctiveness

    PubMed Central

    Reilly, M.; Machado, N.; Blumstein, S. E.

    2015-01-01

    Recent models of semantic memory propose that the semantic representation of concepts is based, in part, on a network of features. In this view, a feature that is distinctive for an object (a zebra has stripes) is processed differently from a feature that is shared across many objects (a zebra has four legs). The goal of this paper is to determine whether there are hemispheric differences in such processing. In a feature verification task, participants responded ‘yes’ or ‘no’ following concepts which were presented to a single visual field (left or right) paired with a shared or distinctive feature. Both hemispheres showed faster reaction times to shared features than to distinctive features, although right hemisphere responses were significantly slower overall and particularly in the processing of distinctive features. These findings support models of semantic processing in which the dominant left hemisphere more efficiently performs highly discriminating ‘fine’ encoding, in contrast to the right hemisphere which performs less discriminating ‘coarse’ encoding. PMID:26022059

  9. A comparison between semi-spheroid- and dome-shaped quantum dots coupled to wetting layer

    NASA Astrophysics Data System (ADS)

    Shahzadeh, Mohammadreza; Sabaeian, Mohammad

    2014-06-01

    During the epitaxial growth method, self-assembled semi-spheroid-shaped quantum dots (QDs) are formed on the wetting layer (WL). However for sake of simplicity, researchers sometimes assume semi-spheroid-shaped QDs to be dome-shaped (hemisphere). In this work, a detailed and comprehensive study on the difference between electronic and transition properties of dome- and semi-spheroid-shaped quantum dots is presented. We will explain why the P-to-S intersubband transition behaves the way it does. The calculated results for intersubband P-to-S transition properties of quantum dots show two different trends for dome-shaped and semi-spheroid-shaped quantum dots. The results are interpreted using the probability of finding electron inside the dome/spheroid region, with emphasis on the effects of wetting layer. It is shown that dome-shaped and semi-spheroid-shaped quantum dots feature different electronic and transition properties, arising from the difference in lateral dimensions between dome- and semi-spheroid-shaped QDs. Moreover, an analogy is presented between the bound S-states in the quantum dots and a simple 3D quantum mechanical particle in a box, and effective sizes are calculated. The results of this work will benefit researchers to present more realistic models of coupled QD/WL systems and explain their properties more precisely.

  10. Spin-forming Project Report

    SciTech Connect

    Switzner, Nathan; Henry, Dick

    2009-03-20

    In a second development order, spin-forming equipment was again evaluated using the test shape, a hemispherical shell. In this second development order, pure vanadium and alloy titanium (Ti-6Al-4V) were spin-formed, as well as additional copper and 21-6-9 stainless. In the first development order the following materials had been spin-formed: copper (alloy C11000 ETP), 6061 aluminum, 304L stainless steel, 21-6-9 stainless steel, and tantalum-2.5% tungsten. Significant challenges included properly adjusting the rotations-per-minute (RPM), cracking at un-beveled edges and laser marks, redressing of notches, surface cracking, non-uniform temperature evolution in the titanium, and cracking of the tailstock. Lessons learned were that 300 RPM worked better than 600 RPM for most materials (at the feed rate of 800 mm/min); beveling the edges to lower the stress reduces edge cracking; notches, laser marks, or edge defects in the preform doom the process to cracking and failure; coolant is required for vanadium spin-forming; increasing the number of passes to nine or more eliminates surface cracking for vanadium; titanium develops a hot zone in front of the rollers; and the tailstock should be redesigned to eliminate the cylindrical stress concentrator in the center.

  11. Speech disorders in right-hemisphere stroke.

    PubMed

    Dyukova, G M; Glozman, Z M; Titova, E Y; Kriushev, E S; Gamaleya, A A

    2010-07-01

    Clinical practice shows that right-hemisphere cerebral strokes are often accompanied by one speech disorder or another. The aim of the present work was to analyze published data addressing speech disorders in right-sided strokes. Questions of the lateralization of speech functions are discussed, with particular reference to the role of the right hemisphere in speech activity and the structure of speech pathology in right-hemisphere foci. Clinical variants of speech disorders, such as aphasia, dysprosody, dysarthria, mutism, and stutter are discussed in detail. Types of speech disorders are also discussed, along with the possible mechanisms of their formation depending on the locations of lesions in the axis of the brain (cortex, subcortical structures, stem, cerebellum) and focus size.

  12. Dynamic contribution to hemispheric mean temperature trends

    SciTech Connect

    Wallace, J.M.; Zhang, Y.; Renwick, J.A.

    1995-11-03

    On the basis of land station data from the Northern Hemisphere, it was determined that roughly half of the temporal variance of monthly mean hemispheric mean anomalies in surface air temperature during the period from 1900 through 1990 were linearly related to the amplitude of a distinctive spatial pattern in which the oceans are anomalously cold and the continents are anomalously warm poleward of 40 degrees north when the hemisphere is warm. Apart from an upward trend since 1975, to which El Nino has contributed, the amplitude time series associated with this pattern resembles seasonally dependent white noise. it is argued that the variability associated with this pattern is dynamically induced and is not necessarily an integral part of the fingerprint of global warming. 12 refs., 5 figs., 1 tab.

  13. Single Mode Lasing from Hybrid Hemispherical Microresonators

    PubMed Central

    Chen, Rui; Van Duong Ta; Sun, Han Dong

    2012-01-01

    Enormous attention has been paid to optical microresonators which hold a great promise for microlasers as well as fundamental studies in cavity quantum electrodynamics. Here we demonstrate a three-dimensional (3D) hybrid microresonator combining self-assembled hemispherical structure with a planar reflector. By incorporating dye molecules into the hemisphere, optically pumped lasing phenomenon is observed at room temperature. We have studied the lasing behaviors with different cavity sizes, and particularly single longitudinal mode lasing from hemispheres with diameter ∼15 μm is achieved. Detailed characterizations indicate that the lasing modes shift under varying pump densities, which can be well-explained by frequency shift and mode hopping. This work provides a versatile approach for 3D confined microresonators and opens an opportunity to realize tunable single mode microlasers. PMID:22540027

  14. Right hemisphere grey matter structure and language outcomes in chronic left hemisphere stroke.

    PubMed

    Xing, Shihui; Lacey, Elizabeth H; Skipper-Kallal, Laura M; Jiang, Xiong; Harris-Love, Michelle L; Zeng, Jinsheng; Turkeltaub, Peter E

    2016-01-01

    The neural mechanisms underlying recovery of language after left hemisphere stroke remain elusive. Although older evidence suggested that right hemisphere language homologues compensate for damage in left hemisphere language areas, the current prevailing theory suggests that right hemisphere engagement is ineffective or even maladaptive. Using a novel combination of support vector regression-based lesion-symptom mapping and voxel-based morphometry, we aimed to determine whether local grey matter volume in the right hemisphere independently contributes to aphasia outcomes after chronic left hemisphere stroke. Thirty-two left hemisphere stroke survivors with aphasia underwent language assessment with the Western Aphasia Battery-Revised and tests of other cognitive domains. High-resolution T1-weighted images were obtained in aphasia patients and 30 demographically matched healthy controls. Support vector regression-based multivariate lesion-symptom mapping was used to identify critical language areas in the left hemisphere and then to quantify each stroke survivor's lesion burden in these areas. After controlling for these direct effects of the stroke on language, voxel-based morphometry was then used to determine whether local grey matter volumes in the right hemisphere explained additional variance in language outcomes. In brain areas in which grey matter volumes related to language outcomes, we then compared grey matter volumes in patients and healthy controls to assess post-stroke plasticity. Lesion-symptom mapping showed that specific left hemisphere regions related to different language abilities. After controlling for lesion burden in these areas, lesion size, and demographic factors, grey matter volumes in parts of the right temporoparietal cortex positively related to spontaneous speech, naming, and repetition scores. Examining whether domain general cognitive functions might explain these relationships, partial correlations demonstrated that grey matter

  15. Right hemisphere grey matter structure and language outcomes in chronic left hemisphere stroke.

    PubMed

    Xing, Shihui; Lacey, Elizabeth H; Skipper-Kallal, Laura M; Jiang, Xiong; Harris-Love, Michelle L; Zeng, Jinsheng; Turkeltaub, Peter E

    2015-10-31

    The neural mechanisms underlying recovery of language after left hemisphere stroke remain elusive. Although older evidence suggested that right hemisphere language homologues compensate for damage in left hemisphere language areas, the current prevailing theory suggests that right hemisphere engagement is ineffective or even maladaptive. Using a novel combination of support vector regression-based lesion-symptom mapping and voxel-based morphometry, we aimed to determine whether local grey matter volume in the right hemisphere independently contributes to aphasia outcomes after chronic left hemisphere stroke. Thirty-two left hemisphere stroke survivors with aphasia underwent language assessment with the Western Aphasia Battery-Revised and tests of other cognitive domains. High-resolution T1-weighted images were obtained in aphasia patients and 30 demographically matched healthy controls. Support vector regression-based multivariate lesion-symptom mapping was used to identify critical language areas in the left hemisphere and then to quantify each stroke survivor's lesion burden in these areas. After controlling for these direct effects of the stroke on language, voxel-based morphometry was then used to determine whether local grey matter volumes in the right hemisphere explained additional variance in language outcomes. In brain areas in which grey matter volumes related to language outcomes, we then compared grey matter volumes in patients and healthy controls to assess post-stroke plasticity. Lesion-symptom mapping showed that specific left hemisphere regions related to different language abilities. After controlling for lesion burden in these areas, lesion size, and demographic factors, grey matter volumes in parts of the right temporoparietal cortex positively related to spontaneous speech, naming, and repetition scores. Examining whether domain general cognitive functions might explain these relationships, partial correlations demonstrated that grey matter

  16. Optimized design of a nanostructured SPCE-based multipurpose biosensing platform formed by ferrocene-tethered electrochemically-deposited cauliflower-shaped gold nanoparticles

    PubMed Central

    Argoubi, Wicem; Saadaoui, Maroua

    2015-01-01

    Summary The demand for on-site nanodevices is constantly increasing. The technology development for the design of such devices is highly regarded. In this work, we report the design of a disposable platform that is structured with cauliflower-shaped gold nanoparticles (cfAuNPs) and we show its applications in immunosensing and enzyme-based detection. The electrochemical reduction of Au(III) allows for the electrodeposition of highly dispersed cauliflower-shaped gold nanoparticles on the surface of screen-printed carbon electrodes (SPCEs). The nanostructures were functionalized using ferrocenylmethyl lipoic acid ester which allowed for the tethering of the ferrocene group to gold, which serves as an electrochemical transducer/mediator. The bioconjugation of the surface with anti-human IgG antibody (α-hIgG) or horseradish peroxidase (HRP) enzyme yields biosensors, which have been applied for the selective electrochemical detection of human IgG (hIgG) or H2O2 as model analytes, respectively. Parameters such as the number of sweeps, amount of charge generated from the oxidation of the electrodeposited gold, time of incubation and concentration of the ferrocene derivatives have been studied using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). Selectivity and specificity tests have been also performed in the presence of potentially interfering substances to either hIgG or H2O2. Results showed that the devised immunosensor is endowed with good selectivity and specificity in the presence of several folds of competitive analytes. The enzyme-based platform showed a good catalytic activity towards H2O2 oxidation which predestined it to potential applications pertaining to enzymatic kinetics studies. The levels of hIgG in human serum and H2O2 in honey were successfully determined and served as assessment tools of the applicability of the platforms for real samples analysis. PMID:26425435

  17. Shape, shell, and vacuole formation during the drying of a single concentrated whey protein droplet.

    PubMed

    Sadek, Céline; Tabuteau, Hervé; Schuck, Pierre; Fallourd, Yannick; Pradeau, Nicolas; Le Floch-Fouéré, Cécile; Jeantet, Romain

    2013-12-17

    The drying of milk concentrate droplets usually leads to specific particle morphology influencing their properties and their functionality. Understanding how the final shape of the particle is formed therefore represents a key issue for industrial applications. In this study, a new approach to the investigation of droplet-particle conversion is proposed. A single droplet of concentrated globular proteins extracted from milk was deposited onto a hydrophobic substrate and placed in a dry environment. Complementary methods (high-speed camera, confocal microscopy, and microbalance) were used to record the drying behavior of the concentrated protein droplets. Our results showed that whatever the initial concentration, particle formation included three dynamic stages clearly defined by the loss of mass and the evolution of the internal and external shapes of the droplet. A new and reproducible particle shape was related in this study. It was observed after drying a smooth, hemispherical cap-shaped particle, including a uniform protein shell and the nucleation of an internal vacuole. The particle morphology was strongly influenced by the drying environment, the contact angle, and the initial protein concentration, all of which governed the duration of the droplet shrinkage, the degree of buckling, and the shell thickness. These results are discussed in terms of specific protein behaviors in forming a predictable and a characteristic particle shape. The way the shell is formed may be the starting point in shaping particle distortion and thus represents a potential means of tuning the particle morphology.

  18. Possible link of the V-shaped phase diagram to the glass-forming ability and fragility in a water-salt mixture.

    PubMed

    Kobayashi, Mika; Tanaka, Hajime

    2011-03-25

    Water is a very poor glass former, but its link to the thermodynamic and kinetic anomalies remains elusive. We experimentally reveal that the glass-forming ability and fragility of a water-salt mixture are closely related to its equilibrium phase diagram. We propose that frustration between local and global orderings controls both the glass-forming ability and the fragility. Relying on the same role of salt and pressure, which commonly break tetrahedral order, we apply this idea to pure water under pressure. This scenario not only explains unusual behavior of water-type liquids such as water, Si, and Ge but also provides a mechanism for a link between the equilibrium phase diagram, glass-forming ability, and fragility for various materials including oxides, chalcogenides, and metallic glasses.

  19. Right Hemisphere Specialization for Color Detection

    ERIC Educational Resources Information Center

    Sasaki, Hitoshi; Morimoto, Akiko; Nishio, Akira; Matsuura, Sumie

    2007-01-01

    Three experiments were carried out to investigate hemispheric asymmetry in color processing among normal participants. In Experiment 1, it was shown that the reaction times (RTs) of the dominant and non-dominant hands assessed using a visual target presented at the central visual field, were not significantly different. In Experiment 2, RTs of…

  20. Meaning Apprehension in the Cerebral Hemispheres

    ERIC Educational Resources Information Center

    Kandhadai, Padmapriya A.

    2009-01-01

    When we hear a word, it is remarkable how we store, activate and rapidly retrieve a vast amount of relevant information within a few hundred milliseconds. This thesis examines how meaning is processed in parallel--but with critical differences--between the two hemispheres of the brain. Event-related brain potentials (ERP) were used to examine…

  1. Hemispherical asymmetry in cusp precipitation near solstices

    SciTech Connect

    Newell, P.T.; Meng, C.

    1988-04-01

    A statistical comparison of the peak flux in electron and ion polar cusp precipitation in the summer and winter hemispheres as observed by the low-altitude DMSP F7 satellite is performed. Data studied encompass four consecutive solstices from December 1983 to June 1985, comprising 77 days of data with a total of 292 individual cusp passes. On each day, observations were restricted to those few hours UT in which the interhemispherical MLT variation of DMSP F7 was smallest. After the remaining local time effect was averaged out, the summer hemisphere ion (electron) precipitating energy flux was larger, on the average, by 61 +- 11% (51 +- 5%) than that in the winter hemisphere. However, the average particle energy was always lower for both species in the summer hemisphere. These effects generally hold true for northward as well as southward interplanetary magnetic fields (IMF). It is argued that the observed asymmetry is very hard to explain if the most intense part of the cusp lies on closed field lines, but it is shown that the standard open field line model of the cusp virtually requires the observed differences to occur. The present results thus suggest that the most intense portion of the cusp lies on open field lines even for northward IMF. copyright American Geophysical Union 1988

  2. Civilisations of the Left Cerebral Hemisphere?

    ERIC Educational Resources Information Center

    Racle, Gabriel L.

    Research conducted by Tadanobu Tsunoda on auditory and visual sensation, designed to test and understand the functions of the cerebral hemispheres, is discussed. Tsunoda discovered that the Japanese responses to sounds by the left and the right sides of the brain are very different from the responses obtained from people from other countries. His…

  3. Right-hemisphere specialization for contour grouping.

    PubMed

    Volberg, Gregor

    2014-01-01

    Previous studies often revealed a right-hemisphere specialization for processing the global level of compound visual stimuli. Here we explore whether a similar specialization exists for the detection of intersected contours defined by a chain of local elements. Subjects were presented with arrays of randomly oriented Gabor patches that could contain a global path of collinearly arranged elements in the left or in the right visual hemifield. As expected, the detection accuracy was higher for contours presented to the left visual field/right hemisphere. This difference was absent in two control conditions where the smoothness of the contour was decreased. The results demonstrate that the contour detection, often considered to be driven by lateral coactivation in primary visual cortex, relies on higher-level visual representations that differ between the hemispheres. Furthermore, because contour and non-contour stimuli had the same spatial frequency spectra, the results challenge the view that the right-hemisphere advantage in global processing depends on a specialization for processing low spatial frequencies.

  4. Hemispheric Learning and the Hispanic Student.

    ERIC Educational Resources Information Center

    Contreras, Maximiliano

    People of different cultures differ in the cognitive style they use. Research reports that Mexican American children indicate a preference for field-sensitive cognitive strategies that are spatial-holistic, and middle class children a preference for field-independent strategies that are verbal-analytic. Brain research in hemisphericity appears to…

  5. An Evaluative Review of Hemispheric Learning Potential

    DTIC Science & Technology

    1985-10-01

    patients with left-sided damage on certain items of the Seashore test of musical abilities...1978) Problem-solving strategies and manifest brain asymmetry. Cortex, 14, 474-484. Wechsler, A.F. (1973) The effect of organic brain disease on ...mologous locales In the two hemispheres. The effects of unilateral brain dam- age were thus interpreted as disorders consequent on

  6. Creative Cognitive Processes and Hemispheric Specialization.

    ERIC Educational Resources Information Center

    Poreh, A. M.; Whitman, R. D.

    1991-01-01

    The relationship between creative thought processes and hemispheric asymmetry was examined in 47 right-handed male undergraduates. Four factors were identified, accounting for 75 percent of the total variance: Verbal Divergent Thinking Factor, Nonverbal Divergent Thinking Factor, Convergent Verbal Search Factor, and Cognitive Complexity Factor.…

  7. Rethinking a Right Hemisphere Deficit in ADHD

    ERIC Educational Resources Information Center

    Hale, T. Sigi; Loo, Sandra K.; Zaidel, Eran; Hanada, Grant; Macion, James; Smalley, Susan L.

    2009-01-01

    Introduction: Early observations from lesion studies suggested right hemisphere (RH) dysfunction in ADHD. However, a strictly right-lateralized deficit has not been well supported. An alternatively view suggests increased R greater than L asymmetry of brain function and abnormal interhemispheric interaction. If true, RH pathology in ADHD should…

  8. Hemispherical and Longitudinal Asymmetries in the Heliospheric Magnetic Field: Flip-flops of a Bashful Ballerina

    NASA Astrophysics Data System (ADS)

    Hiltula, T.; Mursula, K.

    2004-12-01

    Several studies during many decennia have studied possible longitudinal and hemispherical asymmetries in various forms of solar activity. E.g., there are well known periods when one of the solar hemispheres has dominated the other in sunspot numbers, flare occurrence or some other form of solar activity. However, the solar asymmetries have not been found to be very conclusive, or to form any clear systematical patterns (e.g., relation to solar cycle). On the contrary, recent studies of similar longitudinal and hemispherical asymmetries in the heliospheric magnetic field have shown a very clear and systematic behaviour. E.g., it was found recently that the dominance of the two HMF sectors experiences an oscillation with a period of about 3.2 years. This new flip-flop periodicity in the heliospheric magnetic field is most likely related to a similar periodicity recently found in sunspots. Also, it has recently been found that the HMF sector coming from the northern solar hemisphere systematically dominates at 1AU during solar minimum times. This leads to a persistent southward shift or coning of the heliospheric current sheet at these times that can be picturesquely described by the concept of a Bashful Ballerina. This result also implies that the Sun has a large-scale quadrupole magnetic moment. Here we review these recent developments concerning the longitudinal and hemispherical asymmetries in the heliospheric magnetic field and study their inter-connection.

  9. Tuber-specific silencing of asparagine synthetase-1 reduces the acrylamide-forming potential of potatoes grown in the field without affecting tuber shape and yield.

    PubMed

    Chawla, Rekha; Shakya, Roshani; Rommens, Caius M

    2012-10-01

    Simultaneous silencing of asparagine synthetase (Ast)-1 and -2 limits asparagine (ASN) formation and, consequently, reduces the acrylamide-forming potential of tubers. The phenotype of silenced lines appears normal in the greenhouse, but field-grown tubers are small and cracked. Assessing the effects of silencing StAst1 and StAst2 individually, we found that yield drag was mainly linked to down-regulation of StAst2. Interestingly, tubers from untransformed scions grafted onto intragenic StAst1/2-silenced rootstock contained almost the same low ASN levels as those in the original silenced lines, indicating that ASN is mainly formed in tubers rather than being transported from leaves. This conclusion was further supported by the finding that overexpression of StAst2 caused ASN to accumulate in leaves but not tubers. Thus, ASN does not appear to be the main form of organic nitrogen transported from leaves to tubers. Because reduced ASN levels coincided with increased levels of glutamine, it appears likely that this alternative amide amino acid is mobilized to tubers, where it is converted into ASN by StAst1. Indeed, tuber-specific silencing of StAst1, but not of StAst2, was sufficient to substantially lower ASN formation in tubers. Extensive field studies demonstrated that the reduced acrylamide-forming potential achieved by tuber-specific StAst1 silencing did not affect the yield or quality of field-harvested tubers.

  10. Fabrication of liquid-filled square lens array with hemispherical partition walls

    NASA Astrophysics Data System (ADS)

    Koo, Gyohyun; Kim, Junoh; Kim, Cheoljoong; Shin, Dooseub; Lee, Junsik; Won, Yong Hyub

    2016-03-01

    Liquid-filled square lens array has been developed for an alternative to solid lens array because of its advantage in variable focus length. In addition, the square lens array has advantage with high fill factor compared to liquid circular lens array which is another alternative. However, one of the main limitations of conventional square lens array is the distortion. In this paper, distortion-free liquid square lens array is proposed. The partition walls of the proposed square lens array is fabricated into hemispherical shape to reduce the distortion, and then additional vertical walls are set up on the hemispherical structures to unify the height of partition walls and divide chamber sections. UV lithography techniques are used to fabricate this structure, and diffuser which has an angle of 80 degrees is used in the process. Photoresist is exposed to scattered ultraviolet rays which pass through the diffuser, and hemispherical lens-shaped structures of photoresist remains after development process. Supplementary vertical partition walls are obtained by additional photoresist patterning process on the structure. In this structure, the interface between oil and water comes into contact with the surface of the hemispherical walls, and the refractive index of oil and the walls are equally matched to maximize the part which acts as lens in the chamber. The proposed liquid square lens array can provide us with aberration-free 3D images with high fill factor.

  11. Resting state EEG power, intra-hemisphere and inter-hemisphere coherence in bipolar disorder

    NASA Astrophysics Data System (ADS)

    Handayani, Nita; Khotimah, S. N.; Haryanto, F.; Arif, I.; Taruno, Warsito P.

    2017-02-01

    This paper examines the differences of EEG power and coherence between bipolar disorder patients and healthy subjects in the resting state. Observations are focused on the prefrontal cortex area by calculating intra-hemisphere and inter-hemisphere coherence. EEG data acquisition are conducted by using wireless Emotiv Epoc on AF3, AF4, FC5, FC6, F7 and F8 channels. The power spectral analysis shows that in bipolar disoder there is an increase of power in the delta, theta and beta frequencies, and power decrease in the alpha frequency. The coherence test results show that both intra-hemisphere and inter-hemisphere coherence in bipolar disorder patients are lower than healthy subjects. This shows the lack of brain synchronization in bipolar disorder patients.

  12. Ion scattering spectroscopy intensities for supported nanoparticles: The hemispherical cap model

    NASA Astrophysics Data System (ADS)

    Campbell, Charles T.; James, Trevor E.

    2015-11-01

    Nanoparticles of one element or compound dispersed across the surface of another substance form the basis for many materials of great technological importance, like catalysts, fuel cells, sensors and biomaterials. Nanoparticles also often grow during thin film deposition. The size and number density of such nanoparticles are important, often estimated with electron or scanning tunneling microscopies. However, these are slow and often unavailable with sufficient resolution for particles near 1 nm. Because the probe depth of low-energy ion scattering spectroscopy (LEIS) with He+ and Ne+ is so shallow (less than one atom), it provides quantitative information on the fraction of the surface that is covered by such nanoparticles. Combined with the total amount per unit area, this fraction provides the average particle thickness. When the ions are incident or detected at some angle away from the surface normal, macroscopic screening effects cause interpretation of LEIS signals in terms of area fraction covered to be complicated. In this paper, we report a geometric analysis of particles with the shape of hemispherical caps so that LEIS signals obtained in any measurement geometry can also be used to quantitatively determine the area fraction, average particle thickness and diameter, or number density of particles.

  13. Concave-hemisphere-patterned organic top-light emitting device

    DOEpatents

    Forrest, Stephen R; Slootsky, Michael; Lunt, Richard

    2014-01-21

    A first device is provided. The first device includes an organic light emitting device, which further comprises a first electrode, a second electrode, and an organic emissive layer disposed between the first and second electrode. Preferably, the second electrode is more transparent than the first electrode. The organic emissive layer has a first portion shaped to form an indentation in the direction of the first electrode, and a second portion shaped to form a protrusion in the direction of the second electrode. The first device may include a plurality of organic light emitting devices. The indentation may have a shape that is formed from a partial sphere, a partial cylinder, a pyramid, or a pyramid with a mesa, among others. The protrusions may be formed between adjoining indentations or between an indentation and a surface parallel to the substrate.

  14. Concave-hemisphere-patterned organic top-light emitting device

    DOEpatents

    Forrest, Stephen R.; Slootsky, Michael; Lunt, Richard

    2015-06-09

    A first device is provided. The first device includes an organic light emitting device, which further comprises a first electrode, a second electrode, and an organic emissive layer disposed between the first and second electrode. Preferably, the second electrode is more transparent than the first electrode. The organic emissive layer has a first portion shaped to form an indentation in the direction of the first electrode, and a second portion shaped to form a protrusion in the direction of the second electrode. The first device may include a plurality of organic light emitting devices. The indentation may have a shape that is formed from a partial sphere, a partial cylinder, a pyramid, or a pyramid with a mesa, among others. The protrusions may be formed between adjoining indentations or between an indentation and a surface parallel to the substrate.

  15. Choosing words: left hemisphere, right hemisphere, or both? Perspective on the lateralization of word retrieval

    PubMed Central

    Ries, Stephanie K.; Dronkers, Nina F.; Knight, Robert T.

    2015-01-01

    Language is considered to be one of the most lateralized human brain functions. Left hemisphere dominance for language has been consistently confirmed in clinical and experimental settings and constitutes one of the main axioms of neurology and neuroscience. However, functional neuroimaging studies are finding that the right hemisphere also plays a role in diverse language functions. Critically, the right hemisphere may also compensate for the loss or degradation of language functions following extensive stroke-induced damage to the left hemisphere. Here, we review studies that focus on our ability to choose words as we speak. Although fluidly performed in individuals with intact language, this process is routinely compromised in aphasic patients. We suggest that parceling word retrieval into its sub-processes—lexical activation and lexical selection—and examining which of these can be compensated for after left hemisphere stroke can advance the understanding of the lateralization of word retrieval in speech production. In particular, the domain-general nature of the brain regions associated with each process may be a helpful indicator of the right hemisphere's propensity for compensation. PMID:26766393

  16. Choosing words: left hemisphere, right hemisphere, or both? Perspective on the lateralization of word retrieval.

    PubMed

    Riès, Stéphanie K; Dronkers, Nina F; Knight, Robert T

    2016-04-01

    Language is considered to be one of the most lateralized human brain functions. Left hemisphere dominance for language has been consistently confirmed in clinical and experimental settings and constitutes one of the main axioms of neurology and neuroscience. However, functional neuroimaging studies are finding that the right hemisphere also plays a role in diverse language functions. Critically, the right hemisphere may also compensate for the loss or degradation of language functions following extensive stroke-induced damage to the left hemisphere. Here, we review studies that focus on our ability to choose words as we speak. Although fluidly performed in individuals with intact language, this process is routinely compromised in aphasic patients. We suggest that parceling word retrieval into its subprocesses-lexical activation and lexical selection-and examining which of these can be compensated for after left hemisphere stroke can advance the understanding of the lateralization of word retrieval in speech production. In particular, the domain-general nature of the brain regions associated with each process may be a helpful indicator of the right hemisphere's propensity for compensation.

  17. Shaping a high-mass star-forming cluster through stellar feedback. The case of the NGC 7538 IRS 1-3 complex

    NASA Astrophysics Data System (ADS)

    Frau, P.; Girart, J. M.; Zhang, Q.; Rao, R.

    2014-07-01

    Context. NGC 7538 IRS 1-3 is a high-mass star-forming cluster with several detected dust cores, infrared sources, (ultra)compact H II regions, molecular outflows, and masers. In such a complex environment, interactions and feedback among the embedded objects are expected to play a major role in the evolution of the region. Aims: We study the dust, kinematic, and polarimetric properties of the NGC 7538 IRS 1-3 region to investigate the role of the different forces in the formation and evolution of high-mass star-forming clusters. Methods: We performed SMA high angular resolution observations at 880 μm with the compact configuration. We developed the RATPACKS code to generate synthetic velocity cubes from models of choice to be compared to the observational data. To quantify the stability against gravitational collapse we developed the "mass balance" analysis that accounts for all the energetics on core scales. Results: We detect 14 dust cores from 3.5 M⊙ to 37 M⊙ arranged in two larger scale structures: a central bar and a filamentary spiral arm. The spiral arm presents large-scale velocity gradients in H13CO+ 4-3 and C17O 3-2, and magnetic field segments aligned well to the dust main axis. The velocity gradient is reproduced well by a spiral arm expanding at 9 km s-1 with respect to the central core MM1, which is known to power a large precessing outflow. The energy of the outflow is comparable to the spiral-arm kinetic energy, which dominates gravitational and magnetic energies. In addition, the dynamical ages of the outflow and spiral arm are comparable. On core scales, those embedded in the central bar seem to be unstable against gravitational collapse and prone to forming high-mass stars, while those in the spiral arm have lower masses that seem to be supported by non-thermal motions and magnetic fields. Conclusions: The NGC 7538 IRS 1-3 cluster seems to be dominated by protostellar feedback. The dusty spiral arm appears to be formed in a snowplow fashion

  18. Corneal-shaping electrode

    DOEpatents

    Doss, James D.; Hutson, Richard L.

    1982-01-01

    The disclosure relates to a circulating saline electrode for changing corneal shape in eyes. The electrode comprises a tubular nonconductive electrode housing having an annular expanded base which has a surface substantially matched to a subject corneal surface. A tubular conductive electrode connected to a radiofrequency generating source is disposed within the electrode housing and longitudinally aligned therewith. The electrode has a generally hemispherical head having at least one orifice. Saline solution is circulated through the apparatus and over the cornea to cool the corneal surface while radiofrequency electric current emitted from the electrode flows therefrom through the cornea to a second electrode, on the rear of the head. This current heats the deep corneal stroma and thereby effects corneal reshaping as a biological response to the heat.

  19. Asymmetric auroral intensities in the Earth's Northern and Southern hemispheres

    NASA Astrophysics Data System (ADS)

    Laundal, K. M.; Østgaard, N.

    2009-07-01

    It is commonly assumed that the aurora borealis (Northern Hemisphere) and aurora australis (Southern Hemisphere) are mirror images of each other because the charged particles causing the aurora follow the magnetic field lines connecting the two hemispheres. The particles are believed to be evenly distributed between the two hemispheres, from the source region in the equatorial plane of the magnetosphere. Although it has been shown that similar auroral features in the opposite hemispheres can be displaced tens of degree in longitude and that seasonal effects can cause differences in global intensity, the overall auroral patterns were still similar. Here we report observations that clearly contradict the common assumption about symmetric aurora: intense spots are seen at dawn in the Northern summer Hemisphere, and at dusk in the Southern winter Hemisphere. The asymmetry is interpreted in terms of inter-hemispheric currents related to seasons, which have been predicted but hitherto had not been seen.

  20. Hemispheric Brain Preference: What Are the Educational Implications?

    ERIC Educational Resources Information Center

    Fountain, Juanita Cummings; Fillmer, H. Thompson

    1987-01-01

    Investigates the relationship between hemisphere, brain preferences, and academic failure or success by studying 131 average and above average fourth and seventh grade students. Concludes that cerebral hemisphere functions do affect learning. (MM)

  1. Hemisphericity and Journalism--How Do Journalists Think?

    ERIC Educational Resources Information Center

    Vannatta, Bonnie Ann

    1981-01-01

    Reports on a study finding that journalists preferred a right brain hemisphere or integrated style of information processing. Proposes the further application of right-left brain hemisphere research in the field of journalism. (RL)

  2. Comparing parametric solid modelling/reconfiguration, global shape modelling and free-form deformation for the generation of 3D digital models of femurs from X-ray images.

    PubMed

    Filippi, Stefano; Motyl, Barbara; Bandera, Camillo

    2009-02-01

    At present, computer assisted surgery systems help orthopaedic surgeons both plan and perform surgical procedures. To enable these systems to function, it is crucial to have at one's disposal 3D models of anatomical structures, surgical tools and prostheses (if required). This paper analyses and compares three methods for generating 3D digital models of anatomical structures starting from X-ray images: parametric solid modelling/reconfiguration, global shape modelling and free-form deformation. Seven experiences involving the generation of a femur model were conducted by software developers and different skilled users. These experiences are described in detail and compared at different stages and from different points of view.

  3. Mesoscale Temperature Fluctuations in the Southern Hemisphere Stratosphere

    NASA Technical Reports Server (NTRS)

    Gary, Bruce L.

    2008-01-01

    Isentrope surfaces in the Southern Hemisphere stratosphere reveal that air parcels undergo mesoscale temperature fluctuations that depend on latitude and season. The largest temperature fluctuations occur at high latitude winter, whereas the smallest fluctuations occur at high latitude summer. This is the same pattern found for the Northern Hemisphere stratosphere. However, the amplitude of the seasonal dependence in the Southern Hemisphere is only 37% of the Northern Hemisphere's seasonal amplitude.

  4. Visual Hemispheric Specialization: A Computational Theory.

    DTIC Science & Technology

    1985-10-31

    Which is darker green, a Christmas tree or a frozen pea? Which is bigger, a tennis ball or an orange? Most people claim that they visualize the objects...evolved piecemeal, with new components being added, or old ones being modified, to work with those already available. A modularized system is easiest...nor for representing locations in absolute space. In most people , the right hemisphere appears to have become relatively specialized for these

  5. Quaternary glaciations in the Northern Hemisphere

    SciTech Connect

    Sibrava, V.; Bowen, D.Q.; Richmond, G.M.

    1987-01-01

    This volume presents the final report of Project 24 of the International Geological Correlation Programme. The publication is drawn from the contributions of leading individual scientist as well as from scientific research teams. It reflects the present state of knowledge of the Quaternary Glaciations in the Northern Hemisphere and their correlation in space and time, as well as providing a unique summary of climatic change.

  6. Flexible Contrast Gain Control in the Right Hemisphere

    ERIC Educational Resources Information Center

    Okubo, Matia; Nicholls, Michael E. R.

    2005-01-01

    This study investigates whether the right hemisphere has more flexible contrast gain control settings for the identification of spatial frequency. Right-handed participants identified 1 and 9 cycles per degree sinusoidal gratings presented either to the left visual field-right hemisphere (LVF-RH) or the right visual field-left hemisphere (RVF-LH).…

  7. Teaching ESL from the Right Hemisphere of the Brain.

    ERIC Educational Resources Information Center

    Curt, Carmen Judith Nine

    Based on the idea that the brain consists of hemispheres which control different types of behavior, this paper argues that the Puerto Rican school system is deteriorating because its emphasis on left hemisphere (quantitative) activities does not synchronize with Puerto Rico's cultural orientation toward the right hemisphere (qualitative…

  8. Hemisphericity Research: An Overview with Some Implications for Problem Solving.

    ERIC Educational Resources Information Center

    Myers, John T.

    1982-01-01

    Research on cerebral hemisphericity and lateral dominance is reviewed, and relationships between right and left hemispheric modes of information processing as well as problem solving techniques are discussed. Conclusions focus mainly on need for educators to know information processing differences of the two hemispheres to teach children problem…

  9. Hemispheric Specialization and Implications for Education of the Hearing Impaired.

    ERIC Educational Resources Information Center

    Levine, Shari

    The paper reviews research on cerebral hemispheric functioning and considers the implications for instruction of the deaf. The nature of right and left hemisphere function and communication is addressed, as are findings on cerebral asymmetry for aspects of language processing. Studies on hemispheric specialization of hearing impaired persons…

  10. The Influence of Context on Hemispheric Recruitment during Metaphor Processing

    ERIC Educational Resources Information Center

    Diaz, Michele T.; Hogstrom, Larson J.

    2011-01-01

    Although the left hemisphere's prominence in language is well established, less emphasis has been placed on possible roles for the right hemisphere. Behavioral, patient, and neuroimaging research suggests that the right hemisphere may be involved in processing figurative language. Additionally, research has demonstrated that context can modify…

  11. Evidence for Right Hemisphere Phonology in a Backward Masking Task

    ERIC Educational Resources Information Center

    Halderman, Laura K.

    2011-01-01

    The extent to which orthographic and phonological processes are available during the initial moments of word recognition within each hemisphere is under specified, particularly for the right hemisphere. Few studies have investigated whether each hemisphere uses orthography and phonology under constraints that restrict the viewing time of words and…

  12. Brain Hemisphere Dominance: Building the Whole-Brain Singer

    ERIC Educational Resources Information Center

    Boyd, Amanda R.

    2012-01-01

    The concept of brain hemisphere dominance serves as the basis for many educational learning theories. The dominant brain hemisphere guides the learning process, but both hemispheres are necessary for true learning to take place. This treatise outlines and analyzes the dominance factor, a learning theory developed by Dr. Carla Hannaford, which…

  13. Hemispheric Asymmetries in the Activation and Monitoring of Memory Errors

    ERIC Educational Resources Information Center

    Giammattei, Jeannette; Arndt, Jason

    2012-01-01

    Previous research on the lateralization of memory errors suggests that the right hemisphere's tendency to produce more memory errors than the left hemisphere reflects hemispheric differences in semantic activation. However, all prior research that has examined the lateralization of memory errors has used self-paced recognition judgments. Because…

  14. Tectonic Evolution of the Eastern Hemisphere of Mars

    NASA Technical Reports Server (NTRS)

    Pounders, E.; Anderson, R. C.; Dohm, J. M.; Haldemann, A. F. C.; Golombek, M. P.

    2002-01-01

    The magmatic-tectonic history of Mars is largely dominated by the Tharsis magmatic complex of the western hemisphere and the Elysium rise of the eastern hemisphere. In order to address the history of Mars, the tectonic history of the eastern hemisphere must also be unraveled. Additional information is contained in the original extended abstract.

  15. Hemispheric modulations of the attentional networks.

    PubMed

    Spagna, Alfredo; Martella, Diana; Fuentes, Luis J; Marotta, Andrea; Casagrande, Maria

    2016-10-01

    Although several recent studies investigated the hemispheric contributions to the attentional networks using the Attention Network Test (ANT), the role of the cerebral hemispheres in modulating the interaction among them remains unclear. In this study, two lateralized versions of this test (LANT) were used to investigate theal effects on the attentional networks under different conflict conditions. One version, the LANTI-A, presented arrows as target and flankers, while the other version, the LANTI-F, had fruits as target and flankers. Data collected from forty-seven participants confirmed well-known results on the efficiency and interactions among the attentional networks. Further, a left visual field advantage was found when a target occurred in an unattended location (e.g. invalid trials), only with the LANTI-F, but not with LANTI-A. The present study adds more evidence to the hemispheric asymmetry of the orienting of attention, and further reveals patterns of interactions between the attentional networks and the visual fields across different conflicting conditions, underlying the dynamic control of attention in complex environments.

  16. Meteor showers of the southern hemisphere

    NASA Astrophysics Data System (ADS)

    Molau, Sirko; Kerr, Steve

    2014-04-01

    We present the results of an exhaustive meteor shower search in the southern hemisphere. The underlying data set is a subset of the IMO Video Meteor Database comprising 50,000 single station meteors obtained by three Australian cameras between 2001 and 2012. The detection technique was similar to previous single station analysis. In the data set we find 4 major and 6 minor northern hemisphere meteor showers, and 12 segments of the Antihelion source (including the Northern and Southern Taurids and six streams from the MDC working list). We present details for 14 southern hemisphere showers plus the Centaurid and Puppid-Velid complex, with the η Aquariids and the Southern δ Aquariids being the strongest southern showers. Two of the showers (θ^2 Sagittariids and τ Cetids) were previously unknown and have received preliminary designations by the MDC. Overall we find that the fraction of southern meteor showers south of -30deg declination (roughly 25%) is clearly smaller than the fraction of northern meteor showers north of +30deg declination (more than 50%) obtained in our previous analysis.

  17. Comparing forward and inverse models to estimate the seasonal variation of hemisphere-integrated fluxes of carbonyl sulfide

    NASA Astrophysics Data System (ADS)

    Kettle, A. J.; Kuhn, U.; von Hobe, M.; Kesselmeier, J.; Liss, P. S.; Andreae, M. O.

    2002-06-01

    A simple inverse model is proposed to deduce hemisphere-integrated COS flux based on published time series of total column COS. The global atmosphere is divided into two boxes representing the Northern and Southern Hemispheres, and the total column COS data from several stations are used to deduce hemispheric COS loadings. The integrated flux within each hemisphere is calculated as a linear combination of a steady-state solution and time-varying perturbation. The nature of the time-varying perturbation is deduced using two different approaches: an analytic solution based on a cosine function that was fitted to the original total column COS measurement time series and a Simplex optimization with no underlying assumption about the functional form of the total column time series. The results suggest that there is a steady-state COS flux from the Northern to the Southern Hemisphere. There is a seasonal variation superimposed on this flux that in the Southern Hemisphere has a maximum rate of COS input into the atmosphere around January and a maximum rate of COS removal from the atmosphere around August--September. In the Northern Hemisphere, the maximum rate of COS input into the atmosphere is around May--June, and the maximum rate of COS removal is either August or January, depending on which station in the Northern Hemisphere is considered. The results of the inverse model are compared with the outcome of a forward approach on the temporal and spatial variation of the dominant global sources and sinks published earlier. In general, the deduced hemisphere-integrated flux estimates showed good agreement with the database estimates, though it remains uncertain whether COS removal from the atmosphere in the Northern Hemisphere is dominated by plant and soil uptake in the boreal summer or by oceanic uptake in boreal winter.

  18. Comparing forward and inverse models to estimate the seasonal variation of hemisphere-integrated fluxes of carbonyl sulfide

    NASA Astrophysics Data System (ADS)

    Kettle, A. J.; Kuhn, U.; von Hobe, M.; Kesselmeier, J.; Liss, P. S.; Andreae, M. O.

    2002-11-01

    A simple inverse model is proposed to deduce hemisphere-integrated COS flux based on published time series of total column COS. The global atmosphere is divided into two boxes representing the Northern and Southern Hemispheres, and the total column COS data from several stations are used to calculate hemispheric COS loadings. The integrated flux within each hemisphere is calculated as a linear combination of a steady-state solution and time-varying perturbation. The nature of the time-varying perturbation is deduced using two different approaches: an analytic solution based on a cosine function that was fitted to the original total column COS measurement time series and a Simplex optimization with no underlying assumption about the functional form of the total column time series. The results suggest that there is a steady-state COS flux from the Northern to the Southern Hemisphere. There is a seasonal variation superimposed on this flux that in the Southern Hemisphere has a maximum rate of COS input into the atmosphere around January and a maximum rate of COS removal from the atmosphere around August--September. In the Northern Hemisphere, the maximum rate of COS input into the atmosphere is around May--June, and the maximum rate of COS removal is either August or January, depending on which station in the Northern Hemisphere is considered. The results of the inverse model are compared with the outcome of a forward approach on the temporal and spatial variation of the dominant global sources and sinks published earlier. In general, the deduced hemisphere-integrated flux estimates showed good agreement with the database estimates, though it remains uncertain whether COS removal from the atmosphere in the Northern Hemisphere is dominated by plant and soil uptake in the boreal summer or by oceanic uptake in boreal winter.

  19. Words, Hemispheres, and Processing Mechanisms: A Response to Marsolek and Deason (2007)

    ERIC Educational Resources Information Center

    Ellis, Andrew W.; Ansorge, Lydia; Lavidor, Michal

    2007-01-01

    Ellis, Ansorge and Lavidor (2007) [Ellis, A.W., Ansorge, L., & Lavidor, M. (2007). Words, hemispheres, and dissociable subsystems: The effects of exposure duration, case alternation, priming and continuity of form on word recognition in the left and right visual fields. "Brain and Language," 103, 292-303.] presented three experiments investigating…

  20. Latent profiles of executive functioning in healthy young adults: evidence of individual differences in hemispheric asymmetry.

    PubMed

    Rau, Holly K; Suchy, Yana; Butner, Jonathan E; Williams, Paula G

    2016-11-01

    Two competing theoretical models of individual differences in executive functioning (EF) were examined: the Prefrontal Convexity Model and the Hemispheric Asymmetry Model. Neurologically healthy individuals (N = 315; mean age 20.8) completed a modified switching task (MST) and the Attention Network Test (ANT) in a single testing session. Data analysis was conducted in two phases. In the first phase (model identification), latent profile analysis was applied to MST variables measuring the abilities to form, switch, and maintain mental sets under conditions designed to tax left or right hemisphere resources. In the second phase (model validation), participant clusters obtained from the first phase were compared on the ANT. The Model Identification phase yielded a 3-profile solution consistent with the Hemispheric Asymmetry Model. Profile 1 (N = 203) was characterized by average EF performances. Profile 2 (N = 43) revealed a set maintenance weakness under non-verbal conditions. Profile 3 (N = 38) demonstrated weaknesses in cognitive flexibility combined with poor executive performances under verbal conditions. The Model Validation phase confirmed group differences. Profile 1 demonstrated average EF performances. Profile 2 demonstrated distractibility and decreased alertness, consistent with a right hemisphere weakness. Profile 3 demonstrated cognitive rigidity in the absence of external cues, consistent with a left hemisphere weakness. Individual differences in EF appear to follow a Hemispheric Asymmetry Model of EF among neurologically healthy adults. Investigating the relationship between hemispherically mediated executive functions and other individual difference factors known to confer health risk or resilience could inform numerous disciplines within the field of psychology.

  1. Hemispheric View of Venus Centered at the North Pole

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The hemispheric view of Venus, as revealed by more than a decade of radar investigations culminating in the 1990-1994 Magellan mission, is centered on the North Pole. The Magellan spacecraft imaged more than 98% of Venus at a resolution of about 100 meters; the effective resolution of this image is about 3 km. A mosaic of the Magellan images (most with illumination from the west) forms the image base. Gaps in the Magellan coverage were filled with images from the Earth-based Arecibo radar in a region centered roughly on 0 degree latitude and longitude, and with a neutral tone elsewhere (primarily near the south pole). The composite image was processed to improve contrast and to emphasize small features, and was color-coded to represent elevation. Gaps in the elevation data from the Magellan radar altimeter were filled with altimetry from the Venera spacecraft and the U.S. Pioneer Venus missions. An orthographic projection was used, simulating a distant view of one hemisphere of the planet. The Magellan mission was managed for NASA by Jet Propulsion Laboratory (JPL), Pasadena, CA. Data processed by JPL, the Massachusetts Institute of Technology, Cambridge, MA, and the U.S. Geological Survey, Flagstaff, AZ.

  2. Testing the Language of German Cerebral Palsy Patients with Right Hemispheric Language Organization after Early Left Hemispheric Damage

    ERIC Educational Resources Information Center

    Schwilling, Eleonore; Krageloh-Mann, Ingeborg; Konietzko, Andreas; Winkler, Susanne; Lidzba, Karen

    2012-01-01

    Language functions are generally represented in the left cerebral hemisphere. After early (prenatally acquired or perinatally acquired) left hemispheric brain damage language functions may be salvaged by reorganization into the right hemisphere. This is different from brain lesions acquired in adulthood which normally lead to aphasia. Right…

  3. Are reptile and amphibian species younger in the Northern Hemisphere than in the Southern Hemisphere?

    PubMed

    Dubey, Sylvain; Shine, R

    2012-01-01

    A previous analysis of molecular phylogenies suggested that intraspecific diversification had occurred more recently in temperate-zone Northern Hemisphere reptiles and amphibians than in Southern Hemisphere taxa. Here, we test potential explanations for this pattern. We examined published phylogenetic analyses, derived from genetic sequence data, to generate two estimates of the age of species: (i) the oldest intraspecific diversification event within each taxon and (ii) the inferred timing of the split between two sister species. The timing of splits between species shows the same pattern as splits within species, and thus may be due to climatically driven cladogenic and extinction events or may be an artefact of differing levels of taxonomic knowledge about the fauna. Current rates of species descriptions suggest that many more taxa remain to be described in the Southern Hemisphere than the Northern Hemisphere; for that bias to fully explain our results on species age differences, the proportion of undescribed Southern taxa would need to be ≥ 12% in reptiles and ≥ 51% in anurans. For reptiles, taxonomic ignorance plausibly explains the apparent difference in mean age of species between the Southern and Northern Hemispheres; but this explanation can apply to amphibians only if a vast number of Southern taxa remain to be described.

  4. Rat model of focal cerebral ischemia in the dominant hemisphere

    PubMed Central

    Zhang, Hua; Shen, Yan; Wang, Wei; Gao, Huanmin

    2015-01-01

    In the human brain, the dominant hemisphere is more complex than the non-dominant hemisphere. Hence, cerebral ischemia of the dominant hemisphere often leads to serious consequences. This study aims to establish a rodent model of focal cerebral ischemia in the dominant hemisphere. The quadruped feeding test was used to screen 70 male Sprague Dawley rats. From this test, 48 rats with right paw preference were selected and randomly assigned numbers. Half were assigned to the dominant hemisphere ischemia (DHI) group, and the other half were assigned to the non-dominant hemisphere ischemia (NDHI) group. The middle cerebral artery was occluded 2 h before reperfusion. Neurological functions were tested. TTC and HE staining were performed. The volume of cerebral infarction was calculated. Rats in the DHI group had significantly worse neurological scores than rats in the NDHI group (P < 0.05). TTC staining indicated ischemia had more severe consequences in the dominant hemisphere than in the non-dominant hemisphere. The dominant hippocampus indicated severe neuronal loss and disorderly cellular arrangement. The volume of cerebral infarction was also greater in the DHI group compared to the NDHI group (P < 0.05). Compared to MCA occlusion in the non-dominant hemisphere, MCA occlusion in the dominant hemisphere caused greater impairment in neurological functions. The proposed rodent model is reliable and has high levels of reproducibility. Therefore, his model can be reliably for investigating the mechanism of focal cerebral ischemia in the dominant hemisphere of human brains. PMID:25785023

  5. The calculating hemispheres: studies of a split-brain patient.

    PubMed

    Funnell, Margaret G; Colvin, Mary K; Gazzaniga, Michael S

    2007-06-11

    The purpose of the study was to investigate simple calculation in the two cerebral hemispheres of a split-brain patient. In a series of four experiments, the left hemisphere was superior to the right in simple calculation, confirming the previously reported left hemisphere specialization for calculation. In two different recognition paradigms, right hemisphere performance was at chance for all arithmetic operations, with the exception of subtraction in a two-alternative forced choice paradigm (performance was at chance when the lure differed from the correct answer by a magnitude of 1 but above chance when the magnitude difference was 4). In a recall paradigm, the right hemisphere performed above chance for both addition and subtraction, but performed at chance levels for multiplication and division. The error patterns in that experiment suggested that for subtraction and addition, the right hemisphere does have some capacity for approximating the solution even when it is unable to generate the exact solution. Furthermore, right hemisphere accuracy in addition and subtraction was higher for problems with small operands than with large operands. An additional experiment assessed approximate and exact addition in the two hemispheres for problems with small and large operands. The left hemisphere was equally accurate in both tasks but the right hemisphere was more accurate in approximate addition than in exact addition. In exact addition, right hemisphere accuracy was higher for problems with small operands than large, but the opposite pattern was found for approximate addition.

  6. Hemispheric dominance underlying the neural substrate for learned vocalizations develops with experience.

    PubMed

    Chirathivat, Napim; Raja, Sahitya C; Gobes, Sharon M H

    2015-06-22

    Many aspects of song learning in songbirds resemble characteristics of speech acquisition in humans. Genetic, anatomical and behavioural parallels have most recently been extended with demonstrated similarities in hemispheric dominance between humans and songbirds: the avian higher order auditory cortex is left-lateralized for processing song memories in juvenile zebra finches that already have formed a memory of their fathers' song, just like Wernicke's area in the left hemisphere of the human brain is dominant for speech perception. However, it is unclear if hemispheric specialization is due to pre-existing functional asymmetry or the result of learning itself. Here we show that in juvenile male and female zebra finches that had never heard an adult song before, neuronal activation after initial exposure to a conspecific song is bilateral. Thus, like in humans, hemispheric dominance develops with vocal proficiency. A left-lateralized functional system that develops through auditory-vocal learning may be an evolutionary adaptation that could increase the efficiency of transferring information within one hemisphere, benefiting the production and perception of learned communication signals.

  7. Brain Stimulation and the Role of the Right Hemisphere in Aphasia Recovery.

    PubMed

    Turkeltaub, Peter E

    2015-11-01

    Aphasia is a common consequence of left hemisphere stroke and causes a disabling loss of language and communication ability. Current treatments for aphasia are inadequate, leaving a majority of aphasia sufferers with ongoing communication difficulties for the rest of their lives. In the past decade, two forms of noninvasive brain stimulation, repetitive transcranial magnetic stimulation and transcranial direct current stimulation, have emerged as promising new treatments for aphasia. The most common brain stimulation protocols attempt to inhibit the intact right hemisphere based on the hypothesis that maladaptive activity in the right hemisphere limits language recovery in the left. There is now sufficient evidence to demonstrate that this approach, at least for repetitive transcranial magnetic stimulation, improves specific language abilities in aphasia. However, the biological mechanisms that produce these behavioral improvements remain poorly understood. Taken in the context of the larger neurobiological literature on aphasia recovery, the role of the right hemisphere in aphasia recovery remains unclear. Additional research is needed to understand biological mechanisms of recovery, in order to optimize brain stimulation treatments for aphasia. This article summarizes the current evidence on noninvasive brain stimulation methods for aphasia and the neuroscientific considerations surrounding treatments using right hemisphere inhibition. Suggestions are provided for further investigation and for clinicians whose patients ask about brain stimulation treatments for aphasia.

  8. Geomagnetic Field Response at Southern and Northern Hemisphere

    NASA Astrophysics Data System (ADS)

    Chandel, Babita

    Geomagnetic Field Response at Southern and Northern Hemisphere Babita Chandel, Shailendra Saini, Sneha Yadav,S.K.Vijay and A.K.Gwal Space Science Laboratory, Department of Physics, Barkatullah University, Bhopal-462026, India ABSTRACT: This paper represents the geomagnetic field response at Southern Hemisphere (MAITRI) and Northern Hemisphere (TROMSO). The Indian Antarctic Station MAITRI is located at geomagnetic Long. (66.030, 53.210) where as TROMSO is at geomagnetic Long. (66.030, 53.210). We studied the behaviour of geomagnetic field with respect to geomagnetic storms at both the stations TROMSO and MAITRI. It was observed that at Southern Hemisphere there is more variation in winter as compared to the summer season, where as in Northern Hemisphere the variations are more in summer as compared to winter. As in the Northern hemisphere the magnetospheric plasma is strongly turbulized in summer and in Southern hemisphere the magentospheric plasma is strongly turbulized in winter.

  9. Design and Fabrication of Micro Hemispheric Shell Resonator with Annular Electrodes

    PubMed Central

    Wang, Renxin; Bai, Bing; Feng, Hengzhen; Ren, Ziming; Cao, Huiliang; Xue, Chenyang; Zhang, Binzhen; Liu, Jun

    2016-01-01

    Electrostatic driving and capacitive detection is widely used in micro hemispheric shell resonators (HSR). The capacitor gap distance is a dominant factor for the initial capacitance, and affects the driving voltage and sensitivity. In order to decrease the equivalent gap distance, a micro HSR with annular electrodes fabricated by a glassblowing method was developed. Central and annular cavities are defined, and then the inside gas drives glass softening and deformation at 770 °C. While the same force is applied, the deformation of the hemispherical shell is about 200 times that of the annular electrodes, illustrating that the deformation of the electrodes will not affect the measurement accuracy. S-shaped patterns on the annular electrodes and internal-gear-like patterns on the hemispherical shell can improve metal malleability and avoid metal cracking during glass expansion. An arched annular electrode and a hemispheric shell are demonstrated. Compared with HSR with a spherical electrode, the applied voltage could be reduced by 29%, and the capacitance could be increased by 39%, according to theoretical and numerical calculation. The surface roughness of glass after glassblowing was favorable (Rq = 0.296 nm, Ra = 0.217 nm). In brief, micro HSR with an annular electrode was fabricated, and its superiority was preliminarily confirmed. PMID:27897977

  10. Croll revisited: Why is the northern hemisphere warmer than the southern hemisphere?

    NASA Astrophysics Data System (ADS)

    Kang, Sarah M.; Seager, Richard; Frierson, Dargan M. W.; Liu, Xiaojuan

    2015-03-01

    The question of why, in the annual-mean, the northern hemisphere (NH) is warmer than the southern hemisphere (SH) is addressed, revisiting an 1870 paper by James Croll. We first show that ocean is warmer than land in general which, acting alone, would make the SH, with greater ocean fraction, warmer. Croll was aware of this and thought it was caused by greater specific humidity and greenhouse trapping over ocean than over land. However, for any given temperature, it is shown that greenhouse trapping is actually greater over land. Instead, oceans are warmer than land because of the smaller surface albedo. However, hemispheric differences in planetary albedo are negligible because the impact of differences in land-sea fraction are offset by the SH ocean and land reflecting more than their NH counterparts. In the absence of a role for albedo differences it is shown that, in agreement with Croll, northward cross-equatorial ocean heat transport (X-OHT) is critical for the warmer NH. This is examined in a simple box model based on the energy budget of each hemisphere. The hemispheric difference forced by X-OHT is enhanced by the positive water vapor-greenhouse feedback, and is partly compensated by the southward atmospheric energy transport. Due to uncertainties in the ocean data, a range of X-OHT is considered. A X-OHT of larger than 0.5 PW is needed to explain the warmer NH solely by X-OHT. For smaller X-OHT, a larger basic state greenhouse trapping in the NH, conceived as imposed by continental geometry, needs to be imposed. Numerical experiments with a GCM coupled to a slab ocean provide evidence that X-OHT is fundamentally important in determining the hemispheric differences in temperature. Therefore, despite some modifications to his theory, analysis of modern data confirms Croll's 140-year-old theory that the warmer NH is partly because of northward X-OHT.

  11. Inter-Hemispherical Currents for Realistic Model of Ionospheric Conductivity

    NASA Astrophysics Data System (ADS)

    Lyatsky, S.; Khazanov, G. V.

    2013-12-01

    We present results of modeling of the global 3-D ionosphere-magnetosphere current system including in addition to the R1 and R2 field-aligned currents also inter-hemispherical currents. The inter-hemispherical currents flow between Northern and Southern conjugate ionospheres in case of a North-South asymmetry in ionospheric conductivity in two hemispheres. These currents link together the ionospheric currents in two hemispheres, so the currents observed in one hemisphere can provide us with information about currents in the opposite hemisphere, which is especially important when their magnitude can not be obtained from direct observation (e.g., in Antarctica). In this study, we investigate the generation of the inter-hemispherical currents for several distributions of ionospheric conductivity in two hemispheres including a simplified model of ionospheric conductivity, which is important for better understanding of the expected distribution and magnitude of these currents, and a more realistic model of ionospheric conductivity, which is observed during magnetospheric substorms, when the geometry of the inter-hemispherical currents is more complicated. Simulation results show that the inter-hemispherical currents during substorms could play a very significant role, and neglecting these currents does not allow obtaining the correct picture of 3-D magnetosphere-ionosphere current system. These currents are an important part of 3-D field-aligned current system, and they are especially strong during summer-winter months, when they are comparable in magnitude with the R2 currents (about ~0.5 MA). Inter-hemispherical currents map. Left panel is related to Northern hemisphere, right panel to Southern. R1 and R2 currents are not shown; their locations are indicated by the red and blue dashed circles, respectively. The inter-hemispherical currents appear inside the auroral zone in the region of conductivity gradient. The currents in both hemispheres are equal in magnitude and

  12. Laser shaping of cartilage

    NASA Astrophysics Data System (ADS)

    Sobol, Emil N.; Bagratashvili, Victor N.; Omelchenko, Alexander I.; Sviridov, Alexander P.; Helidonis, Emmanuel S.; Kavvalos, George; Christodoulou, P. N.; Naoumidi, I.; Velegrakis, G.; Ovchinnikov, Yuriy M.; Shechter, A.

    1994-09-01

    The carbon dioxide laser has been used for the first time to change the cartilage's shape. After the laser irradiation the cartilage has the tendency to retain its new form. Different types of laser modified cartilage structures were studied. The inferred physical mechanism for cartilage shaping using the stresses relaxation process is presented. The clinical significance of the results for corrective laser surgery is discussed.

  13. HUBBLE SPOTS NORTHERN HEMISPHERIC CLOUDS ON URANUS

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Using visible light, astronomers for the first time this century have detected clouds in the northern hemisphere of Uranus. The newest images, taken July 31 and Aug. 1, 1997 with NASA Hubble Space Telescope's Wide Field and Planetary Camera 2, show banded structure and multiple clouds. Using these images, Dr. Heidi Hammel (Massachusetts Institute of Technology) and colleagues Wes Lockwood (Lowell Observatory) and Kathy Rages (NASA Ames Research Center) plan to measure the wind speeds in the northern hemisphere for the first time. Uranus is sometimes called the 'sideways' planet, because its rotation axis is tipped more than 90 degrees from the planet's orbit around the Sun. The 'year' on Uranus lasts 84 Earth years, which creates extremely long seasons - winter in the northern hemisphere has lasted for nearly 20 years. Uranus has also been called bland and boring, because no clouds have been detectable in ground-based images of the planet. Even to the cameras of the Voyager spacecraft in 1986, Uranus presented a nearly uniform blank disk, and discrete clouds were detectable only in the southern hemisphere. Voyager flew over the planet's cloud tops near the dead of northern winter (when the northern hemisphere was completely shrouded in darkness). Spring has finally come to the northern hemisphere of Uranus. The newest images, both the visible-wavelength ones described here and those taken a few days earlier with the Near Infrared and Multi-Object Spectrometer (NICMOS) by Erich Karkoschka (University of Arizona), show a planet with banded structure and detectable clouds. Two images are shown here. The 'aqua' image (on the left) is taken at 5,470 Angstroms, which is near the human eye's peak response to wavelength. Color has been added to the image to show what a person on a spacecraft near Uranus might see. Little structure is evident at this wavelength, though with image-processing techniques, a small cloud can be seen near the planet's northern limb (rightmost

  14. Hubble Spots Northern Hemispheric Clouds on Uranus

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Using visible light, astronomers for the first time this century have detected clouds in the northern hemisphere of Uranus. The newest images, taken July 31 and Aug. 1, 1997 with NASA Hubble Space Telescope's Wide Field and Planetary Camera 2, show banded structure and multiple clouds. Using these images, Dr. Heidi Hammel (Massachusetts Institute of Technology) and colleagues Wes Lockwood (Lowell Observatory) and Kathy Rages (NASA Ames Research Center) plan to measure the wind speeds in the northern hemisphere for the first time.

    Uranus is sometimes called the 'sideways' planet, because its rotation axis tipped more than 90 degrees from the planet's orbit around the Sun. The 'year' on Uranus lasts 84 Earth years, which creates extremely long seasons - winter in the northern hemisphere has lasted for nearly 20 years. Uranus has also been called bland and boring, because no clouds have been detectable in ground-based images of the planet. Even to the cameras of the Voyager spacecraft in 1986, Uranus presented a nearly uniform blank disk, and discrete clouds were detectable only in the southern hemisphere. Voyager flew over the planet's cloud tops near the dead of northern winter (when the northern hemisphere was completely shrouded in darkness).

    Spring has finally come to the northern hemisphere of Uranus. The newest images, both the visible-wavelength ones described here and those taken a few days earlier with the Near Infrared and Multi-Object Spectrometer (NICMOS) by Erich Karkoschka (University of Arizona), show a planet with banded structure and detectable clouds.

    Two images are shown here. The 'aqua' image (on the left) is taken at 5,470 Angstroms, which is near the human eye's peak response to wavelength. Color has been added to the image to show what a person on a spacecraft near Uranus might see. Little structure is evident at this wavelength, though with image-processing techniques, a small cloud can be seen near the planet's northern limb

  15. Has Northern Hemisphere Heat Flow Been Underestimated?

    NASA Astrophysics Data System (ADS)

    Gosnold, W. D.; Majorowicz, J.; Safanda, J.; Szewczyk, J.

    2005-05-01

    We present three lines of evidence to suggest the hypothesis that heat flow in the northern hemisphere may have been underestimated by 15 to 60 percent in shallow wells due to a large post-glacial warming signal. First, temperature vs. depth (T-z) measurements in parts of Europe and North America show a systematic increase in heat flow with depth. This phenomenon is best recognized in analyses of deep (greater than 2km) boreholes in non-tectonic regions with normal to low background heat flow. In Europe, the increase in heat flow with depth has been observed by analysis of more than 1500 deep boreholes located throughout the Fennoscandian Shield, East European Platform, Danish Basin, Germany, Czech Republic, and Poland. There are significantly fewer deep boreholes in North America, but the increase in heat flow with depth appears in a suite of 759 sites in the IHFC Global Heat Flow Database for the region east of the Rocky Mountains and north of latitude 40 N. Second, surface heat flow values in southern hemisphere shields average approximately 50 mWm-2, but surface heat flow values in northern hemisphere shields average 33 mWm-2. Unless crustal radioactivity or mantle heat flow or both factors are greater in southern hemisphere continents, there is no reason for the northern and southern shield areas having similar ages to have different heat flow values. Third, two recently published surface heat flow maps show anomalously low heat flow in the Canadian Shield in a pattern that is coincident with the Wisconsinan ice sheet. The coincidence of low heat flow and ice accumulation has no geophysical basis, thus the coincidence may suggest the existence of a transient signal caused by a warming event. Recent studies of heat flow in North America indicate that in several sites, the ice base temperature was close to the pressure melting point. We hypothesize that there may have been cold ice-free periods during the Pleistocene that would account for the apparent colder

  16. Phenological changes in the southern hemisphere.

    PubMed

    Chambers, Lynda E; Altwegg, Res; Barbraud, Christophe; Barnard, Phoebe; Beaumont, Linda J; Crawford, Robert J M; Durant, Joel M; Hughes, Lesley; Keatley, Marie R; Low, Matt; Morellato, Patricia C; Poloczanska, Elvira S; Ruoppolo, Valeria; Vanstreels, Ralph E T; Woehler, Eric J; Wolfaardt, Anton C

    2013-01-01

    Current evidence of phenological responses to recent climate change is substantially biased towards northern hemisphere temperate regions. Given regional differences in climate change, shifts in phenology will not be uniform across the globe, and conclusions drawn from temperate systems in the northern hemisphere might not be applicable to other regions on the planet. We conduct the largest meta-analysis to date of phenological drivers and trends among southern hemisphere species, assessing 1208 long-term datasets from 89 studies on 347 species. Data were mostly from Australasia (Australia and New Zealand), South America and the Antarctic/subantarctic, and focused primarily on plants and birds. This meta-analysis shows an advance in the timing of spring events (with a strong Australian data bias), although substantial differences in trends were apparent among taxonomic groups and regions. When only statistically significant trends were considered, 82% of terrestrial datasets and 42% of marine datasets demonstrated an advance in phenology. Temperature was most frequently identified as the primary driver of phenological changes; however, in many studies it was the only climate variable considered. When precipitation was examined, it often played a key role but, in contrast with temperature, the direction of phenological shifts in response to precipitation variation was difficult to predict a priori. We discuss how phenological information can inform the adaptive capacity of species, their resilience, and constraints on autonomous adaptation. We also highlight serious weaknesses in past and current data collection and analyses at large regional scales (with very few studies in the tropics or from Africa) and dramatic taxonomic biases. If accurate predictions regarding the general effects of climate change on the biology of organisms are to be made, data collection policies focussing on targeting data-deficient regions and taxa need to be financially and logistically

  17. Hemispheric asymmetry: contributions from brain imaging.

    PubMed

    Hugdahl, Kenneth

    2011-09-01

    A series of studies using functional and structural magnetic resonance imaging, including diffusion tensor imaging measures also, to elucidate the aspects of hemispheric asymmetry are reviewed. It is suggested that laterality evolved as a response to the demands of language and the need for air-based communication which may have necessitated a division of labor between the hemispheres in order to avoid having duplicate copies in both the hemispheres that would increase processing redundancy. This would have put pressure on brain structures related to the evolution of language and speech, such as the left peri-Sylvian region. MRI data are provided showing structural and functional asymmetry in this region of the brain and how fibers connecting the right and left peri-Sylvian regions pass through the corpus callosum. It is further suggested that the so-called Yakelovian-torque, i.e., the twisting of the brain along the longitudinal axis, with the right frontal and left occipital poles protruding beyond the corresponding left and right sides, was necessary for the expansion of the left peri-Sylvian region and the right occipito-parietal regions subserving the processing of spatial relations. Functional magnetic resonance imaging data related to sex differences for visuo-spatial processing are presented showing enhanced right-sided activation in posterior parts of the brain in both sexes, and frontal activation including Broca's area in the female group only, suggesting that males and females use different strategies when solving a cognitive task. The paper ends with a discussion of the role of the corpus callosum in laterality and the role played by structural asymmetry in understanding corresponding functional asymmetry. WIREs Cogni Sci 2011 2 461-478 DOI: 10.1002/wcs.122 For further resources related to this article, please visit the WIREs website.

  18. Spatial disorientation in right-hemisphere infarction.

    PubMed Central

    Meerwaldt, J D; van Harskamp, F

    1982-01-01

    Spatial orientation was tested with the rod orientation test. The subjects were 40 normal controls and 68 brain-damaged patients with cerebral infarcts. Patients in whom the lesion included the post-rolandic region of the right hemisphere performed worse than controls or patients with lesions at other sites. Patients with an exclusively postrolandic (usually occipital) lesion showed higher error rates than patients with a combined prerolandic and postrolandic lesion, but only for the visual part of the test. These patients were re-examined one year after the stroke. Most of them showed an incomplete recovery of spatial function. PMID:7119828

  19. The genus Platychara from the Western Hemisphere

    USGS Publications Warehouse

    Peck, R.E.; Forester, R.M.

    1979-01-01

    The systematics of four species belonging to the genus Platychara (Charophyta) from the Western Hemisphere is discussed. Three of the species, as defined herein, occur in Cretaceous and Paleocene rocks from Mexico through South America. The type species, P. compressa (Peck and Reker) Grambast, also of Cretaceous and Paleocene age, is herein restricted to deposits north of Mexico. These latter restrictions geographically separate P. compressa and P. perlata as presently defined but the relationship between these two species is still uncertain. A new species, P. grambastii, is proposed for specimens from Maestrichtian sediments in Jamaica. ?? 1979.

  20. Cognitive correlates of hemispheric performance on dichotic tasks.

    PubMed

    Johnson, R C; Green, P; Ahern, F M; Cole, R E

    Older (age 50+) adults were tested twice on three measures of dichotic memory and once on three measures of cognition. Internal consistencies of all three measures generally were adequate. However, test-retest reliabilities, by ear of presentation, were comparatively low for the three dichotic measures. A measure of vocabulary (a left hemisphere dominant cognitive ability) was related to performance on most dichotic tasks. Years of education (an index of left hemisphere mediated crystallized intelligence) was related to performance on left but not right hemisphere function on two of three dichotic tasks. Performance on tests of spatial ability was related to performance on left ear/right hemisphere but not right ear/left hemisphere function on two of three dichotic memory tasks. Individual differences in accuracy of recall and recognition of stimuli presented via dichotic tasks to the right ear/left hemisphere and the left ear/right hemisphere appear to have different cognitive correlates. Right hemisphere performance on dichotic tasks generally shows a significant negative association with age, as did performance on right hemisphere dominant cognitive tasks. On the other hand, most measures of left hemisphere performance showed no decline associated with age.

  1. Hemispheric specialization in dogs for processing different acoustic stimuli.

    PubMed

    Siniscalchi, Marcello; Quaranta, Angelo; Rogers, Lesley J

    2008-01-01

    Considerable experimental evidence shows that functional cerebral asymmetries are widespread in animals. Activity of the right cerebral hemisphere has been associated with responses to novel stimuli and the expression of intense emotions, such as aggression, escape behaviour and fear. The left hemisphere uses learned patterns and responds to familiar stimuli. Although such lateralization has been studied mainly for visual responses, there is evidence in primates that auditory perception is lateralized and that vocal communication depends on differential processing by the hemispheres. The aim of the present work was to investigate whether dogs use different hemispheres to process different acoustic stimuli by presenting them with playbacks of a thunderstorm and their species-typical vocalizations. The results revealed that dogs usually process their species-typical vocalizations using the left hemisphere and the thunderstorm sounds using the right hemisphere. Nevertheless, conspecific vocalizations are not always processed by the left hemisphere, since the right hemisphere is used for processing vocalizations when they elicit intense emotion, including fear. These findings suggest that the specialisation of the left hemisphere for intraspecific communication is more ancient that previously thought, and so is specialisation of the right hemisphere for intense emotions.

  2. Complementary hemispheric specialization for word and accent detection.

    PubMed

    Berman, Steven M; Mandelkern, Mark A; Phan, Hao; Zaidel, Eran

    2003-06-01

    When we hear a familiar word pronounced in a foreign accent, which parts of the brain identify the word and which identify the accent? Here we present converging evidence from PET blood flow, event-related scalp potentials, and behavioral responses during dichotic listening, showing homologous and complementary hemispheric specialization for word and accent detection. Accuracy of detecting target words was greater when stimuli were presented to the right ear, indicating left hemisphere specialization, with no ear advantage for detecting target accents. Detection of words also produced increased blood flow in a left frontal area associated with motor and phonetic processing, and a left temporal area associated with semantic memory. Homologous areas of the right hemisphere, together with right prefrontal and precuneus regions, showed increased blood flow during detection of accents. Separate analyses for each detection task indicated that voxels whose activity maximally correlated with accuracy were in the left hemisphere for word detection, but in the right hemisphere for accent detection. Voxels whose activity maximally correlated with inaccuracy were in the opposite hemisphere for both tasks, strengthening the interpretation that between-task differences in brain activation are related to lateralized specializations for task performance. ERP waveforms and reaction times suggested that greater left hemisphere activation during word detection preceded greater right hemisphere activation during accent detection. The results are interpreted as supporting left hemisphere specialization for extraction of the linguistic, phonetic, and semantic information contained in speech, and right hemisphere specialization for pragmatics, the social context of linguistic communication.

  3. Inter-hemispheric asymmetry of Pedersen conductance

    NASA Astrophysics Data System (ADS)

    Deng, Y.; Lu, Y.; Sheng, C.; Yue, X.

    2015-12-01

    Ionospheric conductance is very important to the magnetosphere-ionosphere coupling in the high latitude region, since it connects the polar cap potential with the currents. Meanwhile, the altitudinal distribution of Pederson conductance gives us a rough idea about the altitudinal distribution of Joule heating at high latitudes. Based on the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites observations of electron density profiles from 2009-2014, Pedersen conductivity has been calculated. A climatologic study of the height-integrated Pedersen conductivities in both E (100-150 km) and F (150-600 km) regions and their ratio in different seasons, solar and geomagnetic conditions have been conducted. A significant inter-hemispheric asymmetry is identified in the seasonal variation. Meanwhile, the conductance in both regions and the conductance ratio show a strong dependence on F10.7 and Ap indices. This result will strongly help our understanding of the inter-hemispheric difference in the high-latitude electrodynamics.

  4. Interannual Variability and Trends of Extratropical Ozone, Part II: Southern Hemisphere. Part 2; Southern Hemisphere

    NASA Technical Reports Server (NTRS)

    Yung, Y. L.

    2008-01-01

    A principal component analysis (PCA) is applied to the Southern Hemisphere (SH) total column ozone following the method established for analyzing the data in the Northern Hemisphere (NH) in a companion paper. The interannual variability (IAV) of extratropical O-3 in the SH is characterized by four main modes, which account for 75% of the total variance. The first two leading modes are approximately zonally symmetric and relate to the Southern Hemisphere annular mode and the quasi-biennial oscillation. The third and fourth modes exhibit wavenumber-1 structures. Contrary to the Northern Hemisphere, the third and fourth are nor related to stationary waves. Similar results obtained for the 30 100-hPa geopotential thickness.The decreasing O3 trend in the SH is captured in the first mode. The largest trend is at the South Pole, with value similar to-2 Dobson Units (DU)/yr. Both the spatial pattern and trends in the column ozone are captured by the Goddard Earth Observation System chemistry-climate model (GEOS-CCM) in the SH.

  5. Biocompatible shaped particles from dried multilayer polymer capsules.

    PubMed

    Chen, Jun; Kozlovskaya, Veronika; Goins, Allison; Campos-Gomez, Javier; Saeed, Mohammad; Kharlampieva, Eugenia

    2013-11-11

    We demonstrated a simple and facile approach to fabricate biocompatible monodisperse hollow microparticles of controlled geometry. The hemispherical, spherical, and cubical microparticles are obtained by drying multilayer capsules of hydrogen-bonded poly(N-vinylpyrrolidone)/tannic acid (PVPON/TA)n. Drying spherical capsules results in hemispherical particles if 15 < n < 20. This shape transformation is controlled by capsule stiffness, which is regulated by the layer number, capsule diameter, and PVPON molecular weight. Cubical and spherical hollow particles maintaining their three-dimensional shapes in the dry state are obtained if n ≥ 25.5. A 17-fold stiffness increase is required to lead from totally collapsed (PVPON/TA)5.5 to dried self-supporting (PVPON/TA)25.5 particles of 2 μm in dimensions. All hollow particles could be further resuspended in aqueous solutions while retaining their shapes upon rehydration. The cell growth and viability studies using human cancer cells revealed noncytotoxic properties of the (PVPON/TA) multilayer particles. Both spherical and hemispherical capsules were internalized by macrophages with the uptake of the hemispherical particles per cell two times more efficient. The method presented here allows for a robust preparation of biocompatible shaped particles whose shape and dimensions can be easily tuned by controlling capsule size and wall thickness. The reported structures can be potentially useful for biomedical applications such as shape-controlled cellular uptake and flow dynamics.

  6. First Geological Mapping Investigation of the Kerwan Hemisphere of Ceres (0-180°E), from NASA’s Dawn Mission

    NASA Astrophysics Data System (ADS)

    Scully, Jennifer E. C.; Williams, David A.; Mest, Scott C.; Buczkowski, Debra L.; Jaumann, Ralf; Raymond, Carol A.; Russell, Christopher T.; Roatsch, Thomas; Preusker, Frank; Park, Ryan; Natheus, Andreas; Hoffmann, Martin; Schafer, Michael; Platz, Thomas; Schenk, Paul M.; Marchi, Simone; O'Brien, David P.; De Sanctis, Maria C.

    2015-11-01

    The Dawn Science team divided the surface of Ceres into quadrangles, in order to facilitate systematic geological mapping, which is a tool used to methodically observe and interpret the surfaces of planetary bodies. Here we present a geological map of the Kerwan hemisphere of Ceres (0-180°E), which we assemble from a combination of quadrangle-scale geological maps. Ceres’ Kerwan hemisphere is dominated by smooth plains, which surround the 284-km-diameter Kerwan crater. The smooth material has a lower abundance of craters than other parts of the Kerwan hemisphere, and may suggest that regional resurfacing has occurred. The current topography data also indicates that broad, positive topography features are present within Kerwan crater. In addition, there are ejecta deposits surrounding Haulani and Dantu craters, which are distinctive in photometrically corrected mosaics and color composite mosaics. These ejecta deposits may contribute to the #1 and #2 bright albedo regions observed by Li et al. (2006) with the Hubble Space Telescope. In the northern region, there are homogeneously distributed impact craters, most of which are circular, shallow, flat-floored and contain central mounds. Polygonal craters are also observed, which may provide inferences about the target materials in which they formed. In the southern region there are numerous craters containing central mounds and smooth material in their interiors. For example, the 129-km-diameter Zadeni crater contains a broad central mound. Moreover, lobate deposits are found in numerous craters in the Kerwan hemisphere, which are likely formed by mass wasting. Ongoing work will include the development of a detailed geological history and the use of crater morphologies to infer the composition and physical properties of the sub-surface. Currently, our geological mapping is based on Approach (~1.3 km/pixel) and Survey (~400 m/pixel) mosaics of clear and color filter data from the Dawn spacecraft’s Framing Camera

  7. Dominant hemisphere lateralization of cortical parasympathetic control as revealed by frontotemporal dementia

    PubMed Central

    Guo, Christine C.; Sturm, Virginia E.; Zhou, Juan; Gennatas, Efstathios D.; Trujillo, Andrew J.; Hua, Alice Y.; Crawford, Richard; Stables, Lara; Kramer, Joel H.; Rankin, Katherine; Levenson, Robert W.; Rosen, Howard J.; Miller, Bruce L.; Seeley, William W.

    2016-01-01

    The brain continuously influences and perceives the physiological condition of the body. Related cortical representations have been proposed to shape emotional experience and guide behavior. Although previous studies have identified brain regions recruited during autonomic processing, neurological lesion studies have yet to delineate the regions critical for maintaining autonomic outflow. Even greater controversy surrounds hemispheric lateralization along the parasympathetic–sympathetic axis. The behavioral variant of frontotemporal dementia (bvFTD), featuring progressive and often asymmetric degeneration that includes the frontoinsular and cingulate cortices, provides a unique lesion model for elucidating brain structures that control autonomic tone. Here, we show that bvFTD is associated with reduced baseline cardiac vagal tone and that this reduction correlates with left-lateralized functional and structural frontoinsular and cingulate cortex deficits and with reduced agreeableness. Our results suggest that networked brain regions in the dominant hemisphere are critical for maintaining an adaptive level of baseline parasympathetic outflow. PMID:27071080

  8. Antarctic Role in Northern Hemisphere Glaciation

    NASA Astrophysics Data System (ADS)

    Woodard, S. C.; Rosenthal, Y.; Miller, K. G.; Wright, J. D.; Lawrence, K. T.; Chiu, B. K.

    2014-12-01

    The late Pliocene, ~3 million years ago (Ma), is the most recent period in geologic history with elevated atmospheric CO2 and global surface temperature estimates analogous to those projected for the end of the 21st century making it a focus of paleoclimate research. Proxy reconstructions suggest average global sea surface temperatures (SSTs) were ~2-3°C above present during the late Pliocene warm period (~3.3-2.9 Ma). In the North Atlantic, regional SST anomalies reached as much as +6°C and even larger temperature anomalies occurred on land in the northern hemisphere. An episode of global cooling and sea level fall following the warm late Pliocene is attributed to a major expansion of northern hemisphere ice sheets at ~2.73 Ma and referred to as the intensification of northern hemisphere glaciation (NHG). We reconstruct the thermal and geochemical history of North Pacific deep water (ODP Site 1208) from 3.3-2.5 Ma at orbital scale resolution using benthic foraminiferal Mg/Ca and stable isotopic ratios (δ18O, δ13C) in order to evaluate changes in continental ice volume and deep ocean circulation as the climate deteriorated and NHG intensified. We find that the oceanic cooling trend which followed late Pliocene warmth did not occur in the deep Pacific Ocean and an average ~21±10 m sea level equivalent ice growth occurred from 3.15-2.75 Ma prior to the intensification of NHG. Furthermore, both the benthic d18Oc and BWTs in the Pacific are offset from the North Atlantic prior to 2.75 Ma. By ~2.73 Ma (interglacial-glacial cycle G7-G6), the Atlantic-Pacific BWT and d18O gradients were reduced to <1°C and <0.1‰, respectively. We interpret these abrupt hydrographic changes as the initiation of stronger heat and salt transfer from the North Atlantic to the Pacific due to a fundamental change in deep ocean circulation driven by late Pliocene ice growth on Antarctica.

  9. Revisiting the Acanthamoeba species that form star-shaped cysts (genotypes T7, T8, T9, and T17): characterization of seven new Brazilian environmental isolates and phylogenetic inferences.

    PubMed

    Magliano, Ana C M; Teixeira, Marta M G; Alfieri, Silvia C

    2012-01-01

    Free-living amoebae of the genus Acanthamoeba are the agents of both opportunistic and non-opportunistic infections and are frequently isolated from the environment. Of the 17 genotypes (T1-T17) identified thus far, 4 (T7, T8, T9, and T17) accommodate the rarely investigated species of morphological group I, those that form large, star-shaped cysts. We report the isolation and characterization of 7 new Brazilian environmental Acanthamoeba isolates, all assigned to group I. Phylogenetic analyses based on partial (~1200 bp) SSU rRNA gene sequences placed the new isolates in the robustly supported clade composed of the species of morphological group I. One of the Brazilian isolates is closely related to A. comandoni (genotype T9), while the other 6, together with 2 isolates recently assigned to genotype T17, form a homogeneous, well-supported group (2·0% sequence divergence) that likely represents a new Acanthamoeba species. Thermotolerance, osmotolerance, and cytophatic effects, features often associated with pathogenic potential, were also examined. The results indicated that all 7 Brazilian isolates grow at temperatures up to 40°C, and resist under hyperosmotic conditions. Additionally, media conditioned by each of the new Acanthamoeba isolates induced the disruption of SIRC and HeLa cell monolayers.

  10. Voyager 1 Jupiter Southern Hemisphere Movie

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This movie shows a portion of Jupiter in the southern hemisphere over 17Jupiter days. Above the white belt, notice the series of atmospheric vortices headed west. Even these early approach frames show wild dynamics in the roiling environment south of the white belt. Notice the small tumbling white cloud near the center.

    As Voyager 1 approached Jupiter in 1979, it took images of the planet at regular intervals. This sequence is made from 17 images taken once every Jupiter rotation period (about 10 hours). These images were acquired in the Blue filter around Feb. 1, 1979. The spacecraft was about 37 million kilometers from Jupiter at that time.

    This time-lapse movie was produced at JPL by the Image Processing Laboratory in 1979.

  11. Atmospheric Motion in Jupiter's Northern Hemisphere

    NASA Technical Reports Server (NTRS)

    2000-01-01

    True-color (left) and false-color (right) mosaics of Jupiter's northern hemisphere between 10 and 50 degrees latitude. Jupiter's atmospheric motions are controlled by alternating eastward and westward bands of air between Jupiter's equator and polar regions. The direction and speed of these bands influences the color and texture of the clouds seen in this mosaic. The high and thin clouds are represented by light blue, deep clouds are reddish, and high and thick clouds are white. A high haze overlying a clear, deep atmosphere is represented by dark purple. This image was taken by NASA's Galileo spacecraft on April 3, 1997 at a distance of 1.4 million kilometers (.86 million miles).

  12. Onsite-effects of dual-hemisphere versus conventional single-hemisphere transcranial direct current stimulation: A functional MRI study.

    PubMed

    Kwon, Yong Hyun; Jang, Sung Ho

    2012-08-25

    We performed functional MRI examinations in six right-handed healthy subjects. During functional MRI scanning, transcranial direct current stimulation was delivered with the anode over the right primary sensorimotor cortex and the cathode over the left primary sensorimotor cortex using dual-hemispheric transcranial direct current stimulation. This was compared to a cathode over the left supraorbital area using conventional single-hemispheric transcranial direct current stimulation. Voxel counts and blood oxygenation level-dependent signal intensities in the right primary sensorimotor cortex regions were estimated and compared between the two transcranial direct current stimulation conditions. Our results showed that dual-hemispheric transcranial direct current stimulation induced greater cortical activities than single-hemispheric transcranial direct current stimulation. These findings suggest that dual-hemispheric transcranial direct current stimulation may provide more effective cortical stimulation than single-hemispheric transcranial direct current stimulation.

  13. Hemispherical anomaly from asymmetric initial states

    NASA Astrophysics Data System (ADS)

    Ashoorioon, Amjad; Koivisto, Tomi

    2016-08-01

    We investigate if the hemispherical asymmetry in the CMB is produced from "asymmetric" excited initial conditions. We show that in the limit where the deviations from the Bunch-Davies vacuum are large and the scale of new physics is maximally separated from the inflationary Hubble parameter, the primordial power spectrum is modulated only by position-dependent dipole and quadrupole terms. Requiring the dipole contribution in the power spectrum to account for the observed power asymmetry, A =0.07 ±0.022 , we show that the amount of quadrupole terms is roughly equal to A2. The mean local bispectrum, which gets enhanced for the excited initial state, is within the 1 σ bound of Planck 2015 results for a large field model, fNL≃4.17 , but is reachable by future CMB experiments. The amplitude of the local non-Gaussianity modulates around this mean value, depending on the angle that the correlated patches on the 2d CMB surface make with the preferred direction. The amount of variation is minimized for the configuration in which the short and long wavelength modes are around the preferred pole and |k→3|≈|k→l ≈10|≪|k→1|≈|k→2|≈|k→l ≈2500| with fNLmin≈3.64 . The maximum occurs when these modes are at the antipode of the preferred pole, fNLmax≈4.81 . The difference of non-Gaussianity between these two configurations is as large as ≃1.17 , which can be used to distinguish this scenario from other scenarios that try to explain the observed hemispherical asymmetry.

  14. The Tropical Western Hemisphere Warm Pool

    NASA Astrophysics Data System (ADS)

    Wang, C.; Enfield, D. B.

    2002-12-01

    The paper describes and examines variability of the tropical Western Hemisphere warm pool (WHWP) of water warmer than 28.5oC. The WHWP is the second-largest tropical warm pool on Earth. Unlike the Eastern Hemisphere warm pool in the western Pacific, which straddles the equator, the WHWP is entirely north of the equator. At various stages of development the WHWP extends over parts of the eastern North Pacific, the Gulf of Mexico, the Caribbean, and the western tropical North Atlantic. It has a large seasonal cycle and its interannual fluctuations of area and intensity are significant. Surface heat fluxes warm the WHWP through the boreal spring to an annual maximum of SST and WHWP area in the late summer/early fall, associated with eastern North Pacific and Atlantic hurricane activities and rainfall from northern South America to the southern tier of the United States. Observations suggest that a positive ocean-atmosphere feedback operating through longwave radiation and associated cloudiness seems to operate in the WHWP. During winter preceding large warm pool, there is an alteration of the Walker and Hadley circulation cells that serves as a "tropospheric bridge" for transferring Pacific ENSO effects to the Atlantic sector and inducing initial warming of warm pool. Associated with the warm SST anomalies is a decrease in sea level pressure anomalies and an anomalous increase in atmospheric convection and cloudiness. The increase in convective activity and cloudiness results in less net longwave radiation loss from the sea surface, which then reinforces SST anomalies.

  15. Molecular phylogenetics and evolutionary history of sect. Quinquefoliae (Pinus): implications for Northern Hemisphere biogeography.

    PubMed

    Hao, Zhen-Zhen; Liu, Yan-Yan; Nazaire, Mare; Wei, Xiao-Xin; Wang, Xiao-Quan

    2015-06-01

    Climatic changes and tectonic events in the Cenozoic have greatly influenced the evolution and geographic distribution of the temperate flora. Such consequences should be most evident in plant groups that are ancient, widespread, and diverse. As one of the most widespread genera of trees, Pinus provides a good model for investigating the history of species diversification and biogeographic disjunction in the Northern Hemisphere. In this study, we reconstructed the phylogeny and investigated the evolutionary and biogeographic history of sect. Quinquefoliae (Pinus), a species-rich lineage disjunctly distributed in Asia, Europe and North America, based on complete taxon sampling and by using nine DNA fragments from chloroplast (cp), mitochondrial (mt) and nuclear genomes. The monophyly of the three subsections, Krempfianae, Gerardianae, and Strobus, is well-supported by cpDNA and nuclear gene phylogenies. However, neither subsect. Gerardianae nor subsect. Strobus forms a monophyletic group in the mtDNA phylogeny, in which sect. Quinquefoliae was divided into two major clades, one consisting of the North American and northeastern Asian species as well as the European P. peuce of subsect. Strobus, and the other comprising the remaining Eurasian species belonging to three subsections. The significant topological incongruence among the gene trees, in conjunction with divergence time estimation and ancestral area reconstruction, indicates that both ancient and relatively recent introgressive hybridization events occurred in the evolution of sect. Quinquefoliae, particularly in northeastern Asia and northwestern North America. In addition, the phylogenetic analysis suggests that the species of subsect. Strobus from subtropical eastern Asia and neighboring areas may have a single origin, although species non-monophyly is very widespread in the nuclear gene trees. Moreover, our study seems to support a Tethyan origin of sect. Quinquefoliae given the distributions and

  16. Bacteria form tellurium nanocrystals

    USGS Publications Warehouse

    Oremland, R.S.

    2007-01-01

    A team of researchers have found two bacterial species that produce tellurium oxyanions as respiratory electron acceptors for growth, leaving elemental tellurium in the form of nanoparticles. The crystals from the two organisms exhibit distinctively different structures. Bacillus selenitireducens initially forms nanorods that cluster together to form rosettes. Sulfurospirillum barnesii forms irregularly-shaped nanospheres that coalesce into larger composite aggregates.

  17. Activity of the northern and southern hemispheres as a basis of the solar cycle manifestation

    NASA Astrophysics Data System (ADS)

    Ryabov, M. I.

    2015-12-01

    The dynamics of the evolution of solar cycles is considered a result of the activity manifestation in the northern and southern hemispheres. A study was performed based on separate datasets for the northern and southern hemispheres that contain the monthly and daily averages of the areas of sunspot groups for the period covering activity cycles from 12 to 24 (1874-2013) and the daily values of the Wolf number in the northern and southern hemispheres during cycles 23-24 (1992-2013).To obtain a pattern of development of the "northern" and "southern" solar cycles in detail, a special technique for the extended application of the wavelet analysis has been developed. It allows different the wave processes forming a solar cycle to be distinguished, together with the time of their existence. The application of bandpass Fourier filtering to the obtained data shows that the length of "11-year" cycles by the index S p varies from 10.2 to 11.5 years in the northern hemisphere and from 9.7 to 13.2 years in the southern. The 19th "northern" and 18th "southern" cycles turned out to be maximal. The formation of each of the cycles by all activity indices is determined by the joint effect of long-period processes lasting from 3 to 7 years and short-period processes lasting less than 2 years. When moving from one cycle to another, the long-period processes demonstrate mergings, separations, modulation, and periodic decays. The abnormal activity that appears during the growth, maximum, or decay phase of a cycle is formed at the expense of the simultaneous strengthening of short-period processes, the lengths and "period spectra" of which noticeably differ in the northern and southern hemispheres.

  18. The Holocene perspective of Northern Hemisphere temperature evolution

    NASA Astrophysics Data System (ADS)

    Lohmann, G.; Laepple, T.

    2009-04-01

    The average surface air temperature of the globe has increased by about 0.5°C since the middle of the nineteenth century. Regarding the climate changes observed during the 20th century, it is of particular importance to identify and quantify the environmental changes to put the recent warming in relationship with the natural climate variations at different timescales. Considering the relatively short period of the available instrumental data, the use of paleoclimate records in combination with model simulations proves to be very useful for the estimation of past climate variability. Here we analyse the Holocene temperature evolution of the past 6000 years as well as the recent and projected future climate evolution. For our analysis, we use the output of an ensemble of general circulation models for the mid-Holocene (PMIP II project) and for recent and projected future (CMIP 3 project), complemented by transient simulations over the mid-to-late Holocene. The model data are also compared to observations and proxy data. The general structure of the Northern Hemisphere appears to have a "Hockey Stick" shape: The Northern Hemisphere cooling during the mid-to-late Holocene (neoglaciation) has been partly compensated during the past century. The reason for the Holocene trend lies in the astronomical forcing in conjunction with climate feedbacks whereas the recent and projected future warming trend can be attributed to anthropogenic influence on greenhouse gas concentrations in the atmosphere plus climate feedbacks. It is important to detect regional differences: At low latitudes and over large parts of the open ocean, the present climate is already warmer than that of the mid-Holocene during boreal summer, whereas at mid and high latitudes (especially over land and parts of the Arctic Ocean) the mid-Holocene values will be reached within the next 20-80 years. Seasonality and regional circulation and temperature anomalies are discussed. It is argued that the Holocene

  19. Carbon ion beam focusing using laser irradiated heated diamond hemispherical shells

    SciTech Connect

    Offermann, Dustin T; Flippo, Kirk A; Gaillard, Sandrine A

    2009-01-01

    Experiments preformed at the Los Alamos National Laboratory's Trident Laser Facility were conducted to observe the acceleration and focusing of carbon ions via the TNSA mechanism using hemispherical diamond targets. Trident is a 200TW class laser system with 80J of 1 {micro}m, short-pulse light delivered in 0.5ps, with a peak intensity of 5 x 10{sup 20} W/cm{sup 2}. Targets where Chemical Vapor Deposition (CVD) diamonds formed into hemispheres with a radius of curvature of 400{micro}m and a thickness of 5{micro}m. The accelerated ions from the hemisphere were diagnosed by imaging the shadow of a witness copper mesh grid located 2mm behind the target onto a film pack located 5cm behind the target. Ray tracing was used to determine the location of the ion focal spot. The TNSA mechanism favorably accelerates hydrogen found in and on the targets. To make the carbon beam detectable, targets were first heated to several hundred degrees Celsius using a CW, 532nm, 8W laser. Imaging of the carbon beam was accomplished via an auto-radiograph of a nuclear activated lithium fluoride window in the first layer of the film pack. The focus of the carbon ion beam was determined to be located 630 {+-} 110 {micro}m from the vertex of the hemisphere.

  20. Right-hemisphere reading in a case of developmental deep dyslexia.

    PubMed

    Pitchford, Nicola J; Funnell, Elaine; De Haan, Bianca; Morgan, Paul S

    2007-09-01

    The right-hemisphere hypothesis of deep dyslexia has received support from functional imaging studies of acquired deep dyslexia following damage to the left cerebral hemisphere, but no imaging studies of cases of developmental deep dyslexia, in which brain damage is not suspected, have been reported. In this paper, we report the first evidence of right hyperactivation in an adult case of developmental deep dyslexia. Hyperactivation was observed in the right inferior frontal cortex during functional magnetic resonance imaging (fMRI) of the oral reading of imageable content words and nonwords to which imageable lexical responses were frequently made. No evidence of right hyperactivation was observed in the oral reading of function words, nor during the naming of imageable words in response to pictured objects. The results reveal strategic and selective use of right-hemisphere functions for particular types of written stimuli. We propose that children with developmental deep dyslexia compensate for their lack of phonological skills by accessing right-hemisphere imageable associations that provide a mnemonic for linking written forms to spoken names.

  1. ERP Evidence of Hemispheric Independence in Visual Word Recognition

    ERIC Educational Resources Information Center

    Nemrodov, Dan; Harpaz, Yuval; Javitt, Daniel C.; Lavidor, Michal

    2011-01-01

    This study examined the capability of the left hemisphere (LH) and the right hemisphere (RH) to perform a visual recognition task independently as formulated by the Direct Access Model (Fernandino, Iacoboni, & Zaidel, 2007). Healthy native Hebrew speakers were asked to categorize nouns and non-words (created from nouns by transposing two middle…

  2. Hemispheric Differences in the Effects of Context on Vowel Perception

    ERIC Educational Resources Information Center

    Sjerps, Matthias J.; Mitterer, Holger; McQueen, James M.

    2012-01-01

    Listeners perceive speech sounds relative to context. Contextual influences might differ over hemispheres if different types of auditory processing are lateralized. Hemispheric differences in contextual influences on vowel perception were investigated by presenting speech targets and both speech and non-speech contexts to listeners' right or left…

  3. Specialization of the Cerebral Hemispheres: Implications for Learning.

    ERIC Educational Resources Information Center

    Hiscock, Merrill; Kinsbourne, Marcel

    1987-01-01

    Among conclusions of this review of findings regarding contemporary neuropsychology and cerebral hemisphere specialization as related to learning disabilities are: (1) differential specialization occurs very early; (2) anomalous hemispheric specialization is not necessarily associated with cognitive deficit; and (3) left- and right-hemisphere…

  4. Hemispheric Differences in the Organization of Memory for Text Ideas

    ERIC Educational Resources Information Center

    Long, Debra L.; Johns, Clinton L.; Jonathan, Eunike

    2012-01-01

    The goal of this study was to examine hemispheric asymmetries in episodic memory for discourse. Access to previously comprehended information is essential for mapping incoming information to representations of "who did what to whom" in memory. An item-priming-in-recognition paradigm was used to examine differences in how the hemispheres represent…

  5. Divergent hemispheric reasoning strategies: reducing uncertainty versus resolving inconsistency.

    PubMed

    Marinsek, Nicole; Turner, Benjamin O; Gazzaniga, Michael; Miller, Michael B

    2014-01-01

    Converging lines of evidence from diverse research domains suggest that the left and right hemispheres play distinct, yet complementary, roles in inferential reasoning. Here, we review research on split-brain patients, brain-damaged patients, delusional patients, and healthy individuals that suggests that the left hemisphere tends to create explanations, make inferences, and bridge gaps in information, while the right hemisphere tends to detect conflict, update beliefs, support mental set-shifts, and monitor and inhibit behavior. Based on this evidence, we propose that the left hemisphere specializes in creating hypotheses and representing causality, while the right hemisphere specializes in evaluating hypotheses, and rejecting those that are implausible or inconsistent with other evidence. In sum, we suggest that, in the domain of inferential reasoning, the left hemisphere strives to reduce uncertainty while the right hemisphere strives to resolve inconsistency. The hemispheres' divergent inferential reasoning strategies may contribute to flexible, complex reasoning in the healthy brain, and disruption in these systems may explain reasoning deficits in the unhealthy brain.

  6. Disentangling the Relationship between Hemispheric Asymmetry and Cognitive Performance

    ERIC Educational Resources Information Center

    Hirnstein, Marco; Leask, Stuart; Rose, Jonas; Hausmann, Markus

    2010-01-01

    It is widely believed that advantages of hemispheric asymmetries originated in better cognitive processing, hence it is often implied that the relationship between hemispheric asymmetry and cognitive performance is linearly positive: the higher the degree of lateralization in a specific cognitive domain, the better the performance in a…

  7. Hemispheric Asymmetry in the Efficiency of Attentional Networks

    ERIC Educational Resources Information Center

    Asanowicz, Dariusz; Marzecova, Anna; Jaskowski, Piotr; Wolski, Piotr

    2012-01-01

    Despite the fact that hemispheric asymmetry of attention has been widely studied, a clear picture of this complex phenomenon is still lacking. The aim of the present study was to provide an efficient and reliable measurement of potential hemispheric asymmetries of three attentional networks, i.e. alerting, orienting and executive attention.…

  8. Universality of fragment shapes

    PubMed Central

    Domokos, Gábor; Kun, Ferenc; Sipos, András Árpád; Szabó, Tímea

    2015-01-01

    The shape of fragments generated by the breakup of solids is central to a wide variety of problems ranging from the geomorphic evolution of boulders to the accumulation of space debris orbiting Earth. Although the statistics of the mass of fragments has been found to show a universal scaling behavior, the comprehensive characterization of fragment shapes still remained a fundamental challenge. We performed a thorough experimental study of the problem fragmenting various types of materials by slowly proceeding weathering and by rapid breakup due to explosion and hammering. We demonstrate that the shape of fragments obeys an astonishing universality having the same generic evolution with the fragment size irrespective of materials details and loading conditions. There exists a cutoff size below which fragments have an isotropic shape, however, as the size increases an exponential convergence is obtained to a unique elongated form. We show that a discrete stochastic model of fragmentation reproduces both the size and shape of fragments tuning only a single parameter which strengthens the general validity of the scaling laws. The dependence of the probability of the crack plan orientation on the linear extension of fragments proved to be essential for the shape selection mechanism. PMID:25772300

  9. Universality of fragment shapes

    NASA Astrophysics Data System (ADS)

    Domokos, Gábor; Kun, Ferenc; Sipos, András Árpád; Szabó, Tímea

    2015-03-01

    The shape of fragments generated by the breakup of solids is central to a wide variety of problems ranging from the geomorphic evolution of boulders to the accumulation of space debris orbiting Earth. Although the statistics of the mass of fragments has been found to show a universal scaling behavior, the comprehensive characterization of fragment shapes still remained a fundamental challenge. We performed a thorough experimental study of the problem fragmenting various types of materials by slowly proceeding weathering and by rapid breakup due to explosion and hammering. We demonstrate that the shape of fragments obeys an astonishing universality having the same generic evolution with the fragment size irrespective of materials details and loading conditions. There exists a cutoff size below which fragments have an isotropic shape, however, as the size increases an exponential convergence is obtained to a unique elongated form. We show that a discrete stochastic model of fragmentation reproduces both the size and shape of fragments tuning only a single parameter which strengthens the general validity of the scaling laws. The dependence of the probability of the crack plan orientation on the linear extension of fragments proved to be essential for the shape selection mechanism.

  10. Numerical investigation of hypersonic flat-plate boundary layer transition mechanism induced by different roughness shapes

    NASA Astrophysics Data System (ADS)

    Zhou, Yunlong; Zhao, Yunfei; Xu, Dan; Chai, Zhenxia; Liu, Wei

    2016-10-01

    The roughness-induced laminar-turbulent boundary layer transition is significant for high-speed aerospace applications. The transition mechanism is closely related to the roughness shape. In this paper, high-order numerical method is used to investigate the effect of roughness shape on the flat-plate laminar-to-turbulent boundary layer transition. Computations are performed in both the supersonic and hypersonic regimes (free-stream Mach number from 3.37 up to 6.63) for the square, cylinder, diamond and hemisphere roughness elements. It is observed that the square and diamond roughness elements are more effective in inducing transition compared with the cylinder and hemisphere ones. The square roughness element has the longest separated region in which strong unsteadiness exists and the absolute instability is formed, thus resulting in the earliest transition. The diamond roughness element has a maximum width of the separated region leading to the widest turbulent wake region far downstream. Furthermore, transition location moves backward as the Mach number increases, which indicates that the compressibility significantly suppresses the roughness-induced boundary layer transition.

  11. Hemispheric processing of memory is affected by sleep.

    PubMed

    Monaghan, Padraic; Shaw, John J; Ashworth-Lord, Anneliese; Newbury, Chloe R

    2017-04-01

    Sleep is known to affect learning and memory, but the extent to which it influences behavioural processing in the left and right hemispheres of the brain is as yet unknown. We tested two hypotheses about lateralised effects of sleep on recognition memory for words: whether sleep reactivated recent experiences of words promoting access to the long-term store in the left hemisphere (LH), and whether sleep enhanced spreading activation differentially in semantic networks in the hemispheres. In Experiment 1, participants viewed lists of semantically related words, then slept or stayed awake for 12h before being tested on seen, unseen but related, or unrelated words presented to the left or the right hemisphere. Sleep was found to promote word recognition in the LH, and to spread activation equally within semantic networks in both hemispheres. Experiment 2 ensured that the results were not due to time of day effects influencing cognitive performance.

  12. The prisoners of despair: right hemisphere deficiency and suicide.

    PubMed

    Weinberg, I

    2000-12-01

    This paper presents an integrative approach to understanding of the inner experience of suicidal persons in terms of hemispheric asymmetry. The right hemisphere is involved in formation of polysemantic context. Polysemantic context is determined by multiple interconnections among its elements, while each concrete element bears the stamp of the whole context. Left hemisphere functioning leads to formation of monosemantic context. It is suggested that due to functional insufficiency of the right hemisphere the suicidal person demonstrates a compensatory shift to left hemisphere functioning. This shift manifests itself in reversed asymmetry of neurotransmitters, tendency to dissociation, alienated and negative perception of the body, lower sensitivity to pain, disintegration of self-representation, cognitive constriction, overly general nature of personal memories, difficulties in affect regulation as well as such personality traits as low openness to experience and personal constriction. This hypothesis raises a number of suggestions for future research.

  13. Hemispheric sea ice distribution sets the glacial tempo

    NASA Astrophysics Data System (ADS)

    Lee, Jung-Eun; Shen, Aaron; Fox-Kemper, Baylor; Ming, Yi

    2017-01-01

    The proxy record of global temperature shows that the dominant periodicity of the glacial cycle shifts from 40 kyr (obliquity) to 100 kyr (eccentricity) about a million years ago. Using climate model simulations, here we show that the pace of the glacial cycle depends on the pattern of hemispheric sea ice growth. In a cold climate the sea ice grows asymmetrically between two hemispheres under changes to Earth's orbital precession, because sea ice growth potential outside of the Arctic Circle is limited. This difference in hemispheric sea ice growth leads to an asymmetry in absorbed solar energy for the two hemispheres, particularly when eccentricity is high, even if the annual average insolation is similar. In a warmer climate, the hemispheric asymmetry of the sea ice decreases as mean Arctic and Antarctic sea ice decreases, diminishing the precession and eccentricity signals and explaining the dominant obliquity signal (40 kyr) before the mid-Pleistocene transition.

  14. Atmospheric Blocking in the Northern Hemisphere.

    NASA Astrophysics Data System (ADS)

    Knox, John Lewis

    Blocking is generally understood as the obstruction on a large scale of the normal west - to - east motion of mid-latitude pressure systems. It is a persistent phenomenon lasting from one to several weeks and the resulting prolonged weather regimes may have serious economic and social consequences. The recent Northern Hemisphere winters, starting with 1976 -77, featured unusually large circulation anomalies, many of which can be directly related to prolonged episodes of large scale blocking. The intent of this study is to investigate the statistics and certain diagnostics of blocking in the Northern Hemisphere. The first of the three primary objectives is to present and interpret the spatial and temporal distribution of blocking during the past 33 years. We develop objective identification criteria, adaptable to machine processing methods, by relating the blocking anticyclone to its associated positive anomaly of 5-day mean 500MB height. Anomalies meeting the criteria are called 'blocking signatures.' We present the seasonal frequency of occurrence of these signatures by longitude and by area. The results are in good agreement with published studies for the oceans, but they also reveal a high frequency of blocking signatures over the Northeastern Canadian Archipelago. This result, dubbed the 'Baffin Island Paradox' is further investigated and rationalized. A catalogue has been prepared which identifies the date, centre location and magnitude of every blocking signature which occurred from January 1, 1946 to December 31, 1978. A supplementary Catalogue identifies sequences of these signatures corresponding to actual blocking episodes. The second objective is to investigate whether regions with high incidence of blocking, in either the developing or the mature stage, features non-Gaussian distributions of 5-day mean geopotential. During winter, fields of significantly low kurtosis are found in certain mid-latitude regions where the genesis and amplification of

  15. Seismic hazard map of the western hemisphere

    USGS Publications Warehouse

    Shedlock, K.M.; Tanner, J.G.

    1999-01-01

    Vulnerability to natural disasters increases with urbanization and development of associated support systems (reservoirs, power plants, etc.). Catastrophic earthquakes account for 60% of worldwide casualties associated with natural disasters. Economic damage from earthquakes is increasing, even in technologically advanced countries with some level of seismic zonation, as shown by the 1989 Loma Prieta, CA ($6 billion), 1994 Northridge, CA ($ 25 billion), and 1995 Kobe, Japan (> $ 100 billion) earthquakes. The growth of megacities in seismically active regions around the world often includes the construction of seismically unsafe buildings and infrastructures, due to an insufficient knowledge of existing seismic hazard. Minimization of the loss of life, property damage, and social and economic disruption due to earthquakes depends on reliable estimates of seismic hazard. National, state, and local governments, decision makers, engineers, planners, emergency response organizations, builders, universities, and the general public require seismic hazard estimates for land use planning, improved building design and construction (including adoption of building construction codes), emergency response preparedness plans, economic forecasts, housing and employment decisions, and many more types of risk mitigation. The seismic hazard map of the Americas is the concatenation of various national and regional maps, involving a suite of approaches. The combined maps and documentation provide a useful global seismic hazard framework and serve as a resource for any national or regional agency for further detailed studies applicable to their needs. This seismic hazard map depicts Peak Ground Acceleration (PGA) with a 10% chance of exceedance in 50 years for the western hemisphere. PGA, a short-period ground motion parameter that is proportional to force, is the most commonly mapped ground motion parameter because current building codes that include seismic provisions specify the

  16. Analysis of coupling efficiency on hemispherical fiber lens by method of lines.

    PubMed

    Lambak, Zainuddin; Abdul Rahman, Faidz; Mokhtar, Mohd Ridzuan; Tengku, Imran A

    2009-02-16

    The method of lines (MoL) has been developed to study coupling efficiency on hemispherical lens. In this paper, the physical shape of the lens is approximated by cascading a number of straight waveguide segments. The perfectly matched layer (PML) is applied as an absorber for the MoL to reduce numerical reflection in the simulation region. Analysis is done by calculating coupling efficiency at the plane of integration where the coupling efficiency is an overlap integral between laser diode field and fiber field. The result of coupling efficiency in this analysis is compared to the experiment and ABCD matrix. It is found that MoL gives good result accuracy.

  17. Studying the time histogram of a terrestrial electron beam detected from the opposite hemisphere of its associated TGF

    NASA Astrophysics Data System (ADS)

    Sarria, D.; Blelly, P.-L.; Briggs, M. S.; Forme, F.

    2016-05-01

    Terrestrial gamma-ray flashes are bursts of X/gamma photons, correlated to thunderstorms. By interacting with the atmosphere, the photons produce a substantial number of electrons and positrons. Some of these reach a sufficiently high altitude that their interactions with the atmosphere become negligible, and they are then guided by geomagnetic field lines, forming a Terrestrial Electron Beam. On 9 December 2009, the Gamma-Ray Burst Monitor (GBM) instrument on board the Fermi Space Telescope made a particularly interesting measurement of such an event. To study this type of event in detail, we perform Monte-Carlo simulations and focus on the resulting time histograms. In agreement with previous work, we show that the histogram measured by Fermi GBM is reproducible from a simulation. We then show that the time histogram resulting from this simulation is only weakly dependent on the production altitude, duration, beaming angle, and spectral shape of the associated terrestrial gamma-ray flash. Finally, we show that the time histogram can be decomposed into three populations of leptons, coming from the opposite hemisphere, and mirroring back to the satellite with or without interacting with the atmosphere, and that these populations can be clearly distinguished by their pitch angles.

  18. Hemispheric Contributions to Lexical Ambiguity Resolution in a Discourse Context: Evidence from Individuals with Unilateral Left and Right Hemisphere Lesions

    ERIC Educational Resources Information Center

    Grindrod, C.M.; Baum, S.R.

    2005-01-01

    In the present study, a cross-modal semantic priming task was used to investigate the ability of left-hemisphere-damaged (LHD) nonfluent aphasic, right-hemisphere-damaged (RHD) and non-brain-damaged (NBD) control subjects to use a discourse context to resolve lexically ambiguous words. Subjects first heard four-sentence discourse passages ending…

  19. Beyond Hemispheric Dominance: Brain Regions Underlying the Joint Lateralization of Language and Arithmetic to the Left Hemisphere

    ERIC Educational Resources Information Center

    Pinel, Philippe; Dehaene, Stanislas

    2010-01-01

    Language and arithmetic are both lateralized to the left hemisphere in the majority of right-handed adults. Yet, does this similar lateralization reflect a single overall constraint of brain organization, such an overall "dominance" of the left hemisphere for all linguistic and symbolic operations? Is it related to the lateralization of specific…

  20. Paroxysmal sympathetic hyperactivity in hemispheric intraparenchymal hemorrhage

    PubMed Central

    Gao, Billy; Pollock, Jeffrey A; Hinson, Holly E

    2014-01-01

    Introduction Paroxysmal sympathetic hyperactivity (PSH) is a hyperadrenergic syndrome that may follow acute brain injury characterized by episodic, hyperadrenergic alterations in vital signs. Identifying commonality in lesion localization in patients with PSH is challenging, but intraparenchymal hemorrhage (IPH) represents a focal injury that might provide insight. We describe a series of patients with IPH that developed PSH, and review the literature. Methods Patients with IPH who developed PSH were identified from OHSU hospital records. A literature review was conducted to identify similar cases through PUBMED, OVID, and Google Scholar. Results Three cases meeting criteria for PSH were identified. Hemorrhage volume ranged from 70 to 128 mL, and intracranial hemorrhage score ranged from 2 to 3. The laterality of the hemorrhage and significant volume of hemorrhage was similar in each of the patients, specifically all hemorrhages were large, subcortical, and right-sided. A literature search identified six additional cases, half of whom reported a right hemisphere hemorrhage and the majority also had subcortical localization. Conclusions Our literature review identified six cases of IPH associated with PSH with five cases having subcortical lesion locations, echoing the areas of disruption in our three cases. On the basis of these observations, we hypothesize that injuries along the pathway from the insular cortex to downstream sympathetic centers may remove tonic inhibition leading to unchecked sympathetic outflow. Prospective investigations of lesion location in patients with IPH and PSH are warranted to test this hypothesis, especially with advanced neuroimaging techniques. PMID:24904923

  1. Hemispherical projection lens for insect behavior analysis

    NASA Astrophysics Data System (ADS)

    Aikio, Mika; Takalo, Jouni; Lempeä, Mikko; Vähäsöyrinki, Mikko

    2010-05-01

    Virtual reality projection systems have been used formerly to study if mammals, including humans, are able to act in or understand virtual environments. Insects have been more difficult to study in such circumstances, one of the factors being their large, almost hemispherical field of view. Designing such a projection system that is capable of fulfilling the full field of vision of an insect is a challenging task. Normally, when designing a photographic objective, one of the goals is to minimize field curvature in order to provide sharp image through the whole sensor surface. However, because the image surface in this case is a sphere, flat field is not desirable and the design task becomes an opposite of a typical camera lens. Introducing field curvature becomes mandatory. We have designed and built a system with satisfactory image quality throughout the whole spherical surface with reasonable number of lenses as an add-on for common digital projectors. The manufactured system is able to project an image to a solid angle of 11.95 steradians, and when compared to the whole sphere which is represented with a solid angle of 4π steradians, approximately 5 % of the total sphere area is not illuminated.

  2. Volcanoes and volcanic provinces - Martian western hemisphere

    NASA Technical Reports Server (NTRS)

    Scott, D. H.

    1982-01-01

    The recognition of some Martian landforms as volcanoes is based on their morphology and geologic setting. Other structures, however, may exhibit classic identifying features to a varying or a less degree; these may be only considered provisionally as having a volcanic origin. Regional geologic mapping of the western hemisphere of Mars from Viking images has revealed many more probable volcanoes and volcanotectonic features than were recognized on Mariner 9 pictures. These abundant volcanoes have been assigned to several distinct provinces on the basis of their areal distribution. Although the Olympus-Tharsis region remains as the principle center of volcanism on Mars, four other important provinces are now also recognized: the lowland plains, Tempe Terra plateau, southern highlands (in the Phaethontis and Thaumasia quadrangles), and a probable ignimbrite province, situated along the highland-lowland boundary in Amazonis Planitia. Volcanoes in any one province vary in morphlogy, size, and age, but volcanoes in each province tend to have common characteristics that distinguish that particular group.

  3. Bright Ray Craters in Ganymede's Northern Hemisphere

    NASA Technical Reports Server (NTRS)

    1979-01-01

    GANYMEDE COLOR PHOTOS: This color picture as acquired by Voyager 1 during its approach to Ganymede on Monday afternoon (the 5th of March). At ranges between about 230 to 250 thousand km. The images show detail on the surface with a resolution of four and a half km. This picture is of a region in the northern hemisphere near the terminator. It shows a variety of impact structures, including both razed and unrazed craters, and the odd, groove-like structures discovered by Voyager in the lighter regions. The most striking features are the bright ray craters which have a distinctly 'bluer' color appearing white against the redder background. Ganymede's surface is known to contain large amounts of surface ice and it appears that these relatively young craters have spread bright fresh ice materials over the surface. Likewise, the lighter color and reflectivity of the grooved areas suggests that here, too, there is cleaner ice. We see ray craters with all sizes of ray patterns, ranging from extensive systems of the crater in the southern part of this picture, which has rays at least 300-500 kilometers long, down to craters which have only faint remnants of bright ejects patterns (such as several of the craters in the southern half of PIA01516; P21262). This variation suggests that, as on the Moon, there are processes which act to darken ray material, probably 'gardening' by micrometeoroid impact. JPL manages and controls the Voyager project for NASA's Office of Space Science.

  4. Hemispheric Asymmetries in Mercury’s Exosphere

    NASA Astrophysics Data System (ADS)

    Schmidt, Carl; Baumgardner, J.; Mendillo, M.

    2012-10-01

    Observations of Mercury’s sodium tail by Potter and Killen (2008) frequently show enhanced emission in the northern lobe. Anderson et al. (2011) have established that Mercury’s magnetic dipole is offset from the planet’s center by .2 RM to the north, while approximately aligned with the spin axis. Such a configuration produces an asymmetry in the magnetosphere cusp whereby more plasma has direct access to the planet’s southern hemisphere than in the north (Winslow et al., 2012). Using time-dependent, 3-D simulations, we demonstrate that ion precipitation, enlarged in the south, can actually result in the observed profiles across the tail, which are typically brighter to the north. Additionally, sources located at high latitude cusp footprints at on the dayside were unable match the observed width of the asymmetric profiles across the tail. Instead, our simulations provide evidence for sources near the dawn terminator at lower latitudes, resulting from the accumulation of sodium during the night. Desorption, rather than ion sputtering, is determined to be the responsible mechanism for this sodium population’s release and escape from the planet surface.

  5. Remote Control Southern Hemisphere SSA Observatory

    NASA Astrophysics Data System (ADS)

    Ritchie, I.; Pearson, M.; Sang, J.

    2013-09-01

    EOS Space Systems (EOSSS) is a research and development company which has developed custom observatories, camera and telescope systems for space surveillance since 1996, as well as creating several evolutions of systems control software for control of observatories and laser tracking systems. Our primary reserach observatory is the Space Reserach Centre (SRC) at Mount Stromlo Asutralia. The current SRC control systems are designed such that remote control can be offered for real time data collection, noise filtering and flexible session management. Several imaging fields of view are available simultaneously for tracking orbiting objects, with real time imaging to Mag 18. Orbiting objects can have the centroids post processed into orbital determination/ orbital projection (OD/OP) elements. With or without laser tracking of orbiting objects, they can be tracked in terminator conditions and their OD/OP data created, then enhanced by proprietary methods involving ballistic coefficient estimation and OD convergence pinning, using a priori radar elements. Sensors in development include a thermal imager for satellite thermal signature detection. Extending laser tracking range by use of adaptive optics beam control is also in development now. This Southern Hemisphere observatory is in a unique position to facilitate the study of space debris, either stand-alone or as part of a network such as Falcon. Current national and international contracts will enhance the remote control capabilities further, creating a resource ready to go for a wide variety of SSA missions.

  6. Reorganization of syntactic processing following left-hemisphere brain damage: does right-hemisphere activity preserve function?

    PubMed

    Tyler, Lorraine K; Wright, Paul; Randall, Billi; Marslen-Wilson, William D; Stamatakis, Emmanuel A

    2010-11-01

    The extent to which the human brain shows evidence of functional plasticity across the lifespan has been addressed in the context of pathological brain changes and, more recently, of the changes that take place during healthy ageing. Here we examine the potential for plasticity by asking whether a strongly left-lateralized system can successfully reorganize to the right-hemisphere following left-hemisphere brain damage. To do this, we focus on syntax, a key linguistic function considered to be strongly left-lateralized, combining measures of tissue integrity, neural activation and behavioural performance. In a functional neuroimaging study participants heard spoken sentences that differentially loaded on syntactic and semantic information. While healthy controls activated a left-hemisphere network of correlated activity including Brodmann areas 45/47 and posterior middle temporal gyrus during syntactic processing, patients activated Brodmann areas 45/47 bilaterally and right middle temporal gyrus. However, voxel-based morphometry analyses showed that only tissue integrity in left Brodmann areas 45/47 was correlated with activity and performance; poor tissue integrity in left Brodmann area 45 was associated with reduced functional activity and increased syntactic deficits. Activity in the right-hemisphere was not correlated with damage in the left-hemisphere or with performance. Reduced neural integrity in the left-hemisphere through brain damage or healthy ageing results in increased right-hemisphere activation in homologous regions to those left-hemisphere regions typically involved in the young. However, these regions do not support the same linguistic functions as those in the left-hemisphere and only indirectly contribute to preserved syntactic capacity. This establishes the unique role of the left hemisphere in syntax, a core component in human language.

  7. Divergent hemispheric reasoning strategies: reducing uncertainty versus resolving inconsistency

    PubMed Central

    Marinsek, Nicole; Turner, Benjamin O.; Gazzaniga, Michael; Miller, Michael B.

    2014-01-01

    Converging lines of evidence from diverse research domains suggest that the left and right hemispheres play distinct, yet complementary, roles in inferential reasoning. Here, we review research on split-brain patients, brain-damaged patients, delusional patients, and healthy individuals that suggests that the left hemisphere tends to create explanations, make inferences, and bridge gaps in information, while the right hemisphere tends to detect conflict, update beliefs, support mental set-shifts, and monitor and inhibit behavior. Based on this evidence, we propose that the left hemisphere specializes in creating hypotheses and representing causality, while the right hemisphere specializes in evaluating hypotheses, and rejecting those that are implausible or inconsistent with other evidence. In sum, we suggest that, in the domain of inferential reasoning, the left hemisphere strives to reduce uncertainty while the right hemisphere strives to resolve inconsistency. The hemispheres’ divergent inferential reasoning strategies may contribute to flexible, complex reasoning in the healthy brain, and disruption in these systems may explain reasoning deficits in the unhealthy brain. PMID:25374526

  8. Hemispheric asymmetry of electroencephalography-based functional brain networks.

    PubMed

    Jalili, Mahdi

    2014-11-12

    Electroencephalography (EEG)-based functional brain networks have been investigated frequently in health and disease. It has been shown that a number of graph theory metrics are disrupted in brain disorders. EEG-based brain networks are often studied in the whole-brain framework, where all the nodes are grouped into a single network. In this study, we studied the brain networks in two hemispheres and assessed whether there are any hemispheric-specific patterns in the properties of the networks. To this end, resting state closed-eyes EEGs from 44 healthy individuals were processed and the network structures were extracted separately for each hemisphere. We examined neurophysiologically meaningful graph theory metrics: global and local efficiency measures. The global efficiency did not show any hemispheric asymmetry, whereas the local connectivity showed rightward asymmetry for a range of intermediate density values for the constructed networks. Furthermore, the age of the participants showed significant direct correlations with the global efficiency of the left hemisphere, but only in the right hemisphere, with local connectivity. These results suggest that only local connectivity of EEG-based functional networks is associated with brain hemispheres.

  9. Smelling shapes: crossmodal correspondences between odors and shapes.

    PubMed

    Hanson-Vaux, Grant; Crisinel, Anne-Sylvie; Spence, Charles

    2013-02-01

    Crossmodal correspondences between odors and visual stimuli-particularly colors-are well-established in the literature, but there is a paucity of research involving visual shape correspondences. Crossmodal associations between 20 odors (a selection of those commonly found in wine) and visual shape stimuli ("kiki"/"bouba" forms-Köhler W. 1929. Gestalt psychology. New York: Liveright.) were investigated in a sample of 25 participants (mean age of 21 years). The odors were rated along a form scale anchored by 2 shapes, as well as several descriptive adjective scales. Two of the odors were found to be significantly associated with an angular shape (lemon and pepper) and two others with a rounded shape (raspberry and vanilla). Principal component analysis indicated that the hedonic value and intensity of odors are important in this crossmodal association, with more unpleasant and intense smells associated with more angular forms. These results are discussed in terms of their practical applications, such as in the use of bottle, logo, or label shape by marketers of perfume and wine to convey the prominent notes through congruent odor-shape pairing. In conclusion, these results support the existence of widespread crossmodal associations (or correspondences) between odors and visual shape stimuli.

  10. North-Seeking Magnetotactic Gammaproteobacteria in the Southern Hemisphere

    PubMed Central

    Leão, Pedro; Teixeira, Lia C. R. S.; Cypriano, Jefferson; Farina, Marcos; Abreu, Fernanda; Bazylinski, Dennis A.

    2016-01-01

    ABSTRACT Magnetotactic bacteria (MTB) comprise a phylogenetically diverse group of prokaryotes capable of orienting and navigating along magnetic field lines. Under oxic conditions, MTB in natural environments in the Northern Hemisphere generally display north-seeking (NS) polarity, swimming parallel to the Earth's magnetic field lines, while those in the Southern Hemisphere generally swim antiparallel to magnetic field lines (south-seeking [SS] polarity). Here, we report a population of an uncultured, monotrichously flagellated, and vibrioid MTB collected from a brackish lagoon in Brazil in the Southern Hemisphere that consistently exhibits NS polarity. Cells of this organism were mainly located below the oxic-anoxic interface (OAI), suggesting it is capable of some type of anaerobic metabolism. Magnetosome crystalline habit and composition were consistent with elongated prismatic magnetite (Fe3O4) particles. Phylogenetic analysis based on 16S rRNA gene sequencing indicated that this organism belongs to a distinct clade of the Gammaproteobacteria class. The presence of NS MTB in the Southern Hemisphere and the previously reported finding of SS MTB in the Northern Hemisphere reinforce the idea that magnetotaxis is more complex than we currently understand and may be modulated by factors other than O2 concentration and redox gradients in sediments and water columns. IMPORTANCE Magnetotaxis is a navigational mechanism used by magnetotactic bacteria to move along geomagnetic field lines and find an optimal position in chemically stratified sediments. For that, magnetotactic bacteria swim parallel to the geomagnetic field lines under oxic conditions in the Northern Hemisphere, whereas those in the Southern Hemisphere swim antiparallel to magnetic field lines. A population of uncultured vibrioid magnetotactic bacteria was discovered in a brackish lagoon in the Southern Hemisphere that consistently swim northward, i.e., the opposite of the overwhelming majority of other

  11. Improving process performance in Incremental Sheet Forming (ISF)

    NASA Astrophysics Data System (ADS)

    Ambrogio, G.; Filice, L.; Manco, G. L.

    2011-01-01

    Incremental Sheet Forming (ISF) is a relatively new process in which a sheet clamped along the borders is progressively deformed through a hemispherical tool. The tool motion is CNC controlled and the path is designed using a CAD-CAM approach, with the aim to reproduce the final shape contour such as in the surface milling. The absence of a dedicated setup and the related high flexibility is the main point of strength and the reason why several researchers focused their attentions on the ISF process. On the other hand the process slowness is the most relevant drawback which reduces a wider industrial application. In the paper, a first attempt to overcome this process limitation is presented taking into account a relevant speed increasing respect to the values currently used.

  12. Improving process performance in Incremental Sheet Forming (ISF)

    SciTech Connect

    Ambrogio, G.; Filice, L.; Manco, G. L.

    2011-01-17

    Incremental Sheet Forming (ISF) is a relatively new process in which a sheet clamped along the borders is progressively deformed through a hemispherical tool. The tool motion is CNC controlled and the path is designed using a CAD-CAM approach, with the aim to reproduce the final shape contour such as in the surface milling. The absence of a dedicated setup and the related high flexibility is the main point of strength and the reason why several researchers focused their attentions on the ISF process.On the other hand the process slowness is the most relevant drawback which reduces a wider industrial application. In the paper, a first attempt to overcome this process limitation is presented taking into account a relevant speed increasing respect to the values currently used.

  13. Forms in Space.

    ERIC Educational Resources Information Center

    Moore, Paula

    1998-01-01

    Uses the work of M. C. Escher to instruct upper elementary students in the transformation of flat shape into three-dimensional form. Outlines the lesson as a series of sections: (1) reviewing form drawing; (2) creating three-dimensional effects; (3) imagining the forms in an inhabited world; and (4) using color and shading. (DSK)

  14. Pulse shaping with transmission lines

    DOEpatents

    Wilcox, R.B.

    1985-08-15

    A method and apparatus for forming shaped voltage pulses uses passive reflection from a transmission line with nonuniform impedance. The impedance of the reflecting line varies with length in accordance with the desired pulse shape. A high voltage input pulse is transmitted to the reflecting line. A reflected pulse is produced having the desired shape and is transmitted by pulse removal means to a load. Light activated photoconductive switches made of silicon can be utilized. The pulse shaper can be used to drive a Pockels cell to produce shaped optical pulses.

  15. Pulse shaping with transmission lines

    DOEpatents

    Wilcox, Russell B.

    1987-01-01

    A method and apparatus for forming shaped voltage pulses uses passive reflection from a transmission line with nonuniform impedance. The impedance of the reflecting line varies with length in accordance with the desired pulse shape. A high voltage input pulse is transmitted to the reflecting line. A reflected pulse is produced having the desired shape and is transmitted by pulse removal means to a load. Light activated photoconductive switches made of silicon can be utilized. The pulse shaper can be used to drive a Pockels cell to produce shaped optical pulses.

  16. The orbicularis oculi response after hemispheral damage.

    PubMed Central

    Berardelli, A; Accornero, N; Cruccu, G; Fabiano, F; Guerrisi, V; Manfredi, M

    1983-01-01

    The corneal and blink reflexes were evaluated in 20 normal subjects and in 30 patients with motor deficits secondary to unilateral hemispheral lesions of vascular origin. In the normal population there were no differences between subjects below and subjects above 50 years of age. In the patients the reflex evoked by electrical stimulation of the cornea of the clinically affected side was depressed in 24 out of 30 cases. The depression mainly affected the afferent branch of the circuit, which triggers both homolateral and contralateral orbicularis oculi discharge (afferent abnormality). In three cases the depression was exerted concomitantly on the efferent branch (afferent and efferent abnormality) and only in one case was it limited to the efferent branch (efferent abnormality). The late R2 component of the blink reflex was depressed in 15 out of 30 patients. The early R1 component was slightly facilitated on the affected side. The changes of the corneal reflex and of the R2 component of blink reflex were similar, but the blink reflex had a greater safety factor. The patients with an abnormal corneal reflex had more extensive damage than had the patients with normal corneal response, as shown by computer tomography, but the site of the lesion was comparable in the two groups. Conduction through the brain stem circuits mediating the orbicularis oculi response is normally under pyramidal facilitatory influences while facial motoneurons are subjected to pyramidal inhibition. After pyramidal damage the transmission of impulses in the brain stem was slowed down, ultimately to a degree that abolished the reflex. Removal of pyramidal inhibition on facial motoneurons is probably the basis of the slight facilitation of the R1 component of the blink reflex. Images PMID:6311988

  17. Right hemisphere role in cognitive reserve.

    PubMed

    Robertson, Ian H

    2014-06-01

    High levels of education, occupational complexity, and/or premorbid intelligence are associated with lower levels of cognitive impairment than would be expected from a given brain pathology. This has been observed across a range of conditions including Alzheimer's disease (Roe et al., 2010), stroke (Ojala-Oksala et al., 2012), traumatic brain injury (Kesler et al., 2003), and penetrating brain injury (Grafman, 1986). This cluster of factors, which seemingly protect the brain from expressing symptoms of damage, has been termed "cognitive reserve" (Stern, 2012). The current review considers one possible neural network, which may contribute to cognitive reserve. Based on the evidence that the neurotransmitter, noradrenaline mediates cognitive reserve's protective effects (Robertson, 2013) this review identifies the neurocognitive correlates of noradrenergic (NA) activity. These involve a set of inter-related cognitive processes (arousal, sustained attention, response to novelty, and awareness) with a strongly right hemisphere, fronto-parietal localization, along with working memory, which is also strongly modulated by NA. It is proposed that this set of processes is one plausible candidate for partially mediating the protective effects of cognitive reserve. In addition to its biological effects on brain structure and function, NA function may also facilitate networks for arousal, novelty, attention, awareness, and working memory, which collectively provide for a set of additional, cognitive, mechanisms that help the brain adapt to age-related changes and disease. It is hypothesized that to the extent that the lateral surface of the right prefrontal lobe and/or the right inferior parietal lobe maintain structural (white and gray matter) and functional integrity and connectivity, cognitive reserve should benefit and behavioral expression of pathologic damage should thus be mitigated.

  18. On hemispheric differences in evoked potentials to speech stimuli

    NASA Technical Reports Server (NTRS)

    Galambos, R.; Benson, P.; Smith, T. S.; Schulman-Galambos, C.; Osier, H.

    1975-01-01

    Confirmation is provided for the belief that evoked potentials may reflect differences in hemispheric functioning that are marginal at best. Subjects were right-handed and audiologically normal men and women, and responses were recorded using standard EEG techniques. Subjects were instructed to listen for the targets while laying in a darkened sound booth. Different stimuli, speech and tone signals, were used. Speech sounds were shown to evoke a response pattern that resembles that to tone or clicks. Analysis of variances on peak amplitude and latency measures showed no significant differences between hemispheres, however, a Wilcoxon test showed significant differences in hemispheres for certain target tasks.

  19. The Influence of Visual and Auditory Information on the Perception of Speech and Non-Speech Oral Movements in Patients with Left Hemisphere Lesions

    ERIC Educational Resources Information Center

    Schmid, Gabriele; Thielmann, Anke; Ziegler, Wolfram

    2009-01-01

    Patients with lesions of the left hemisphere often suffer from oral-facial apraxia, apraxia of speech, and aphasia. In these patients, visual features often play a critical role in speech and language therapy, when pictured lip shapes or the therapist's visible mouth movements are used to facilitate speech production and articulation. This demands…

  20. Air Pollution Modeling Using A 3-d Hemispheric Nested Model

    NASA Astrophysics Data System (ADS)

    Frohn, L. M.; Christensen, J. H.; Brandt, J.; Hertel, O.

    A 3-D Eulerian transport-chemistry model based on modules and parameterisations from models developed over the last decade at the National Environmental Research Institute (DREAM, DEHM, ACDEP and DEOM) has been developed. The model is hemispheric with currently two nests implemented. The horizontal resolution in the mother domain is 150 km x 150 km. First nest covers the European area wit,h a 50 km x 50 km resolution, second covers the Scandinavian area with a resolution of 16.67 km x 16.67 km. The model employs a chemical scheme (originally 53 species) which has been modified to include a detailed description of the nitrogen chemistry. The concentration of air pollutants, such as sulfur and nitrogen in various forms, has been calculated with the model, applying no nesting as well as one and two nests. The calculated values have been validated by comparison to measurements from more than 200 EMEP monitoring stations. Furthermore deposition of nitrogen to marine waters has been estimated with the model. The goal is to obtain an improved description of spatial and temporal variations in the nutrient deposition to the marine environment. In the presentation the physics and chemistry of the model will be shortly described. Validations of the model calculations by comparison to EMEP measurements will be shown and discussed together with the results of the deposition calculations.

  1. Surface and Intermediate Water Orbital Scale Variability in the Southern Hemisphere Before Northern Hemisphere Glaciation

    NASA Astrophysics Data System (ADS)

    Caballero-Gill, R. P.; Herbert, T.

    2014-12-01

    Very few records depicting orbital timescale variability exist for the Southern Hemisphere during the Pliocene Warm Period (pWP, ~ 2.8-4.1 Ma.). The pWP is of particular interest as it poses a natural laboratory in which to understand climate variability in a world with only a permanent Southern Hemisphere polar ice sheet, poised near a fundamental shift in the Earth system. We report here proxy records that monitor sea surface temperature (alkenone unsaturation), surface productivity (C37total), and intermediate water density and chemistry (benthic foraminifera stable isotopes) from ODP Site 1125 and DSDP 594 (North and South of Chatham Rise, respectively) for the pWP. Surface thermal gradient between sites suggests the Subtropical Front was in place and stationary between sites for most of the pWP, much like it has been during the late Quaternary. All datasets surrounding the northernmost edge of the Southern Ocean show pacing by short Eccentricity (~100kyr) in the pWP at this location. The presence of a substantial ~100 kyr component in paleoclimatic variability contrasts with prior reports of ~ 41 kyr dominance in Pliocene climate cyclicity.

  2. A New Look at the Northern Hemisphere Sea Ice Concentration

    NASA Astrophysics Data System (ADS)

    Stern, H.; Fowler, C.; Fetterer, F.

    2004-12-01

    It is widely recognized that the Arctic sea ice cover has been shrinking over the past 25 years. Our knowledge of hemispheric sea ice concentration and extent comes almost entirely from satellite passive microwave (PM) data collected since 1978. In this study, we use a new data set of Northern Hemisphere sea ice concentration, derived from weekly operational ice charts spanning more than three decades (1972-2003), to re-examine the regional variability and trends in sea ice area and extent. The ice charts from the U.S. National Ice Center have been converted to EASE-Grid format. Source data for the charts include visible and infrared satellite imagery, active radar imagery, PM data, aerial reconnaissance, ship and shore observations, buoys, model output, information from foreign ice services, and climatology. The PM data are used only when all other forms of data are not available. Thus we have a unique gridded data set that is largely independent of the popular PM products that are widely used by the sea ice community. We divided the Arctic and sub-Arctic seas into regions and created monthly time series of sea ice area and extent for each region. We also obtained the monthly NASA Team sea ice concentration products. We re-gridded these to the same EASE-Grid format as the charts, and computed time series of sea ice area and extent for the same regions. We present comparisons of the regional differences and trends seen in the two data sets. We explain the differences based on the source data used in the charts, and the emissivity of sea ice as detected by the PM instruments. Future work with the ice chart data set includes analysis of multiyear, first-year, and new ice concentrations in order to understand the recent record-low summer ice minima; duration of the ice season, as an indicator of climate change; and analysis of the modes of variability of the ice edge, in order to develop a predictive capability for sea ice extent.

  3. Configuration Factors for Exchange of Radiant Energy Between Axisymmetrical Sections of Cylinders, Cones, and Hemispheres and Their Bases

    NASA Technical Reports Server (NTRS)

    Buschman, Albert J., Jr.; Pittman, Claud M.

    1961-01-01

    Radiation-interchange configuration factors are derived for axisymmetrical sections of cylinders, cones, and hemispheres radiating internally to annular and circular sections of their bases and to other axisymmetrical sections. The general procedure of obtaining configuration factors is outlined and the results are presented in the form of equations, tables, and figures.

  4. Hemispheric differences in orthographic and semantic processing as revealed by event-related potentials

    PubMed Central

    Dickson, Danielle S.; Federmeier, Kara D.

    2015-01-01

    Differences in how the right and left hemispheres (RH, LH) apprehend visual words were examined using event-related potentials (ERPs) in a repetition paradigm with visual half-field (VF) presentation. In both hemispheres (RH/LVF, LH/RVF), initial presentation of items elicited similar and typical effects of orthographic neighborhood size, with larger N400s for orthographically regular items (words and pseudowords) than for irregular items (acronyms and meaningless illegal strings). However, hemispheric differences emerged on repetition effects. When items were repeated in the LH/RVF, orthographically regular items, relative to irregular items, elicited larger repetition effects on both the N250, a component reflecting processing at the level of visual form (orthography), and on the N400, which has been linked to semantic access. In contrast, in the RH/LVF, repetition effects were biased toward irregular items on the N250 and were similar in size across item types for the N400. The results suggest that processing in the LH is more strongly affected by wordform regularity than in the RH, either due to enhanced processing of familiar orthographic patterns or due to the fact that regular forms can be more readily mapped onto phonology. PMID:25278134

  5. Determination of the solid angle and response function of a hemispherical spectrograph with injection lens for Auger electrons emitted from long lived projectile states

    SciTech Connect

    Doukas, S.; Madesis, I.; Dimitriou, A.; Zouros, T. J. M.; Laoutaris, A.; Benis, E. P.

    2015-04-15

    We present SIMION 8.1 Monte Carlo type simulations of the response function and detection solid angle for long lived Auger states (lifetime τ ∼ 10{sup −9} − 10{sup −5} s) recorded by a hemispherical spectrograph with injection lens and position sensitive detector used for high resolution Auger spectroscopy of ion beams. Also included in these simulations for the first time are kinematic effects particular to Auger emission from fast moving projectile ions such as line broadening and solid angle limitations allowing for a more accurate and realistic line shape modeling. Our results are found to be in excellent agreement with measured electron line shapes of both long lived 1s2s2p{sup 4}P and prompt Auger projectile states formed by electron capture in collisions of 25.3 MeV F{sup 7+} with H{sub 2} and 12.0 MeV C{sup 4+} with Ne recorded at 0{sup ∘} to the beam direction. These results are important for the accurate evaluation of the 1s2s2p {sup 4}P/{sup 2}P ratio of K-Auger cross sections whose observed non-statistical production by electron capture into He-like ions, recently a field of interesting interpretations, awaits further resolution.

  6. Neural pathway in the right hemisphere underlies verbal insight problem solving.

    PubMed

    Zhao, Q; Zhou, Z; Xu, H; Fan, W; Han, L

    2014-01-03

    Verbal insight problem solving means to break mental sets, to select the novel semantic information and to form novel, task-related associations. Although previous studies have identified the brain regions associated with these key processes, the interaction among these regions during insight is still unclear. In the present study, we explored the functional connectivity between the key regions during solving Chinese 'chengyu' riddles by using event-related functional magnetic resonance imaging. Results showed that both insight and noninsight solutions activated the bilateral inferior frontal gyri, middle temporal gyri and hippocampi, and these regions constituted a frontal to temporal to hippocampal neural pathway. Compared with noninsight solution, insight solution had a stronger functional connectivity between the inferior frontal gyrus and middle temporal gyrus in the right hemisphere. Our study reveals the neural pathway of information processing during verbal insight problem solving, and supports the right-hemisphere advantage theory of insight.

  7. Geological Mapping of the Encounter Hemisphere on Pluto

    NASA Astrophysics Data System (ADS)

    White, O. L.; Moore, J. M.; Stern, S. A.; Weaver, H. A.; Olkin, C. B.; Ennico, K.; Young, L. A.; Cheng, A. F.; New Horizons GGI Theme Team

    2016-06-01

    We present mapping of Pluto's encounter hemisphere performed to date (focusing on Sputnik Planum and the immediately surrounding area) and offer preliminary descriptions of terrains further afield that will be the subject of future mapping.

  8. Summer Temperature Anomalies for the Northern Hemisphere, 1955-2011

    NASA Video Gallery

    This visualization shows a flat map of the Earth with summertime temperature anomalies for the Northern Hemisphere. This analysis compares observed seasonal mean temperatures (June-July-August) to ...

  9. Contact angle of a hemispherical bubble: an analytical approach.

    PubMed

    Teixeira, M A C; Teixeira, P I C

    2009-10-01

    We have calculated the equilibrium shape of the axially symmetric Plateau border along which a spherical bubble contacts a flat wall, by analytically integrating Laplace's equation in the presence of gravity, in the limit of small Plateau border sizes. This method has the advantage that it provides closed-form expressions for the positions and orientations of the Plateau border surfaces. Results are in very good overall agreement with those obtained from a numerical solution procedure, and are consistent with experimental data. In particular we find that the effect of gravity on Plateau border shape is relatively small for typical bubble sizes, leading to a widening of the Plateau border for sessile bubbles and to a narrowing for pendant bubbles. The contact angle of the bubble is found to depend even more weakly on gravity.

  10. Hypothalamic digoxin, hemispheric chemical dominance, and the tridosha theory.

    PubMed

    Kurup, Ravi Kumar; Kurup, Parameswara Achutha

    2003-05-01

    Ayurveda, the traditional Indian System of Medicine, deals with the theory of the three tridosha states (both physical and psychological): Vata, Pitta, and Kapha. They are the three major human constitutional types that both depend on psychological and physical characteristics. The Pitta state is described as a critical, discriminative, and rational psychological state of mind, while the Kapha state is described as being dominant for emotional stimuli. The Vata state is an intermediate unstable shifting state. The Pitta types are of average height and built with well developed musculature. The Vata types are thin individuals with low body mass index. The Kapha types are short stocky individuals that tend toward obesity, and who are sedentary. The study assessed the biochemical differences between right hemispheric dominant, bihemispheric dominant, and left hemispheric dominant individuals, and then compared this with the patterns obtained in the Vata, Pitta, and Kapha states. The isoprenoid metabolites (digoxin, dolichol, and ubiquinone), glycoconjugate metabolism, free radical metabolism, and the RBC membrane composition were studied. The hemispheric chemical dominance in various systemic diseases and psychological states was also investigated. The results showed that right hemispheric chemically dominant/Kapha state had elevated digoxin levels, increased free radical production and reduced scavenging, increased tryptophan catabolites and reduced tyrosine catabolites, increased glycoconjugate levels and increased cholesterol: phospholipid ratio of RBC membranes. Left hemispheric chemically dominant/Pitta states had the opposite biochemical patterns. The patterns were normal or intermediate in the bihemispheric chemically dominant/Vata state. This pattern could be correlated with various systemic and neuropsychiatric diseases and personality traits. Right hemispheric chemical dominance/Kapha state represents a hyperdigoxinemic state with membrane sodium

  11. Elemental Water Impact Test: Phase 1 20-Inch Hemisphere

    NASA Technical Reports Server (NTRS)

    Vassilakos, Gregory J.

    2015-01-01

    Spacecraft are being designed based on LS-DYNA simulations of water landing impacts. The Elemental Water Impact Test (EWIT) series was undertaken to assess the accuracy of LS-DYNA water impact simulations. Phase 1 of the EWIT series featured water impact tests of a 20-inch hemisphere dropped from heights of 5 feet and 10 feet. The hemisphere was outfitted with an accelerometer and three pressure gages. The focus of this report is the correlation of analytical models against test data.

  12. Hypothalamic digoxin, hemispheric chemical dominance, and peptic ulcer disease.

    PubMed

    Kurup, Ravi Kumar; Kurup, Parameswara Achutha

    2003-10-01

    The isoprenoid pathway produces three key metabolites--endogenous digoxin-like factor (EDLF) (membrane sodium-potassium ATPase inhibitor and regulator of neurotransmitter transport), ubiquinone (free radical scavenger), and dolichol (regulator of glycoconjugate metabolism). The pathway was assessed in peptic ulcer and acid peptic disease and its relation to hemispheric dominance studied. The activity of HMG CoA reductase, serum levels of EDLF, magnesium, tryptophan catabolites, and tyrosine catabolites were measured in acid peptic disease, right hemispheric dominant, left hemispheric dominant, and bihemispheric dominant individuals. All the patients with peptic ulcer disease were right-handed/left hemispheric dominant by the dichotic listening test. The pathway was upregulated with increased EDLF synthesis in peptic ulcer disease (PUD). There was increase in tryptophan catabolites and reduction in tyrosine catabolites in these patients. The ubiquinone levels were low and free radical production increased. Dolichol and glycoconjugate levels were increased and lysosomal stability reduced in patients with acid peptic disease (APD). There was increase in cholesterol:phospholipid ratio with decreased glyco conjugate levels in membranes of patients with PUD. Acid peptic disease represents an elevated EDLF state which can modulate gastric acid secretion and the structure of the gastric mucous barrier. It can also lead to persistence of Helicobacter pylori infection. The biochemical pattern obtained in peptic ulcer disease is similar to those obtained in left-handed/right hemispheric chemically dominant individuals. But all the patients with peptic ulcer disease were right-handed/left hemispheric dominant by the dichotic listen ing test. Hemispheric chemical dominance has no correlation with handedness or the dichotic listening test. Peptic ulcer disease occurs in right hemispheric chemically dominant individuals and is a reflection of altered brain function.

  13. How do our brain hemispheres cooperate to avoid false memories?

    PubMed

    Bergert, Susanne

    2013-02-01

    Memories are not always as reliable as they may appear. The occurrence of false memories can be reduced, however, by enhancing the cooperation between the two brain hemispheres. Yet is the communication from left to right hemisphere as helpful as the information transfer from right to left? To address this question, 72 participants were asked to learn 16 word lists. Applying the Deese-Roediger-McDermott paradigm, the words in each list were associated with an unpresented prototype word. In the test condition, learned words and corresponding prototypes were presented along with non-associated new words, and participants were asked to indicate which of the words they recognized. Crucially, both study and test words were projected to only one hemisphere in order to stimulate each hemisphere separately. It was found that false recognitions occurred significantly less often when the right hemisphere studied and the left hemisphere recognized the stimuli. Moreover, only the right-to-left direction of interhemispheric communication reduced false memories significantly, whereas left-to-right exchange did not. Further analyses revealed that the observed reduction of false memories was not due to an enhanced discrimination sensitivity, but to a stricter response bias. Hence, the data suggest that interhemispheric cooperation does not improve the ability to tell old and new apart, but rather evokes a conservative response tendency. Future studies may narrow down in which cognitive processing steps interhemispheric interaction can change the response criterion.

  14. Hemispheric asymmetry in the efficiency of attentional networks.

    PubMed

    Asanowicz, Dariusz; Marzecová, Anna; Jaśkowski, Piotr; Wolski, Piotr

    2012-07-01

    Despite the fact that hemispheric asymmetry of attention has been widely studied, a clear picture of this complex phenomenon is still lacking. The aim of the present study was to provide an efficient and reliable measurement of potential hemispheric asymmetries of three attentional networks, i.e. alerting, orienting and executive attention. Participants (N=125) were tested with the Lateralized Attention Network Test (LANT) that allowed us to investigate the efficiency of the networks in both visual fields (VF). We found a LVF advantage when a target occurred in an unattended location, which seems to reflect right hemisphere superiority in control of the reorienting of attention. Furthermore, a LVF advantage in conflict resolution was observed, which may indicate hemispheric asymmetry of the executive network. No VF effect for alerting was found. The results, consistent with the common notion of general right hemisphere dominance for attention, provide a more detailed account of hemispheric asymmetries of the attentional networks than previous studies using the LANT task.

  15. The nature of hemispheric specialization for prosody perception.

    PubMed

    Witteman, Jurriaan; Goerlich-Dobre, Katharina S; Martens, Sander; Aleman, André; Van Heuven, Vincent J; Schiller, Niels O

    2014-09-01

    Recent evidence suggests a relative right-hemispheric specialization for emotional prosody perception, whereas linguistic prosody perception is under bilateral control. It is still unknown, however, how the hemispheric specialization for prosody perception might arise. Two main hypotheses have been put forward. Cue-dependent hypotheses, on the one hand, propose that hemispheric specialization is driven by specialization for the non-prosody-specific processing of acoustic cues. The functional lateralization hypothesis, on the other hand, proposes that hemispheric specialization is dependent on the communicative function of prosody, with emotional and linguistic prosody processing being lateralized to the right and left hemispheres, respectively. In the present study, the functional lateralization hypothesis of prosody perception was systematically tested by instructing one group of participants to evaluate the emotional prosody, and another group the linguistic prosody dimension of bidimensional prosodic stimuli in a dichotic-listening paradigm, while event-related potentials were recorded. The results showed that the right-ear advantage was associated with decreased latencies for an early negativity in the contralateral hemisphere. No evidence was found for functional lateralization. These findings suggest that functional lateralization effects for prosody perception are small and support the structural model of dichotic listening.

  16. Tone-language speakers show hemispheric specialization and differential cortical processing of contour and interval cues for pitch.

    PubMed

    Bidelman, G M; Chung, W-L

    2015-10-01

    Electrophysiological studies demonstrate that the neural coding of pitch is modulated by language experience and the linguistic relevance of the auditory input; both rightward and leftward asymmetries have been observed in the hemispheric specialization for pitch. In music, pitch is encoded using two primary features: contour (patterns of rises and falls) and interval (frequency separation between tones) cues. Recent evoked potential studies demonstrate that these "global" (contour) and "local" (interval) aspects of pitch are processed automatically (but bilaterally) in trained musicians. Here, we examined whether alternate forms of pitch expertise, namely, tone-language experience (i.e., Chinese), influence the early detection of contour and intervallic deviations within ongoing pitch sequences. Neuroelectric mismatch negativity (MMN) potentials were recorded in Chinese speakers and English-speaking nonmusicians in response to continuous pitch sequences with occasional global or local deviations in the ongoing melodic stream. This paradigm allowed us to explore potential cross-language differences in the hemispheric weighting for contour and interval processing of pitch. Chinese speakers showed differential pitch encoding between hemispheres not observed in English listeners; Chinese MMNs revealed a rightward bias for contour processing but a leftward hemispheric laterality for interval processing. In contrast, no asymmetries were observed in the English group. Collectively, our findings suggest tone-language experience sensitizes auditory brain mechanisms for the detection of subtle global/local pitch changes in the ongoing auditory stream and exaggerates functional asymmetries in pitch processing between cerebral hemispheres.

  17. Non-conjugate aurora and inter hemispheric currents

    NASA Astrophysics Data System (ADS)

    Reistad, J. P.; Østgaard, N.; Laundal, K. M.; Oksavik, K.

    2012-04-01

    We look at large scale auroral features using global imagers to obtain simultaneous pictures of both the southern and northern auroral ovals in the ultra violet part of the spectra. During the years 2001 and 2002 the IMAGE satellite was in a favourable position for imaging the aurora borealis (Northern Hemisphere) and the POLAR satellite with its large field-of-view VIS Earth camera had a sporadic coverage of the aurora australis (Southern Hemisphere). In total 19 hours of simultaneous global imaging from different seasons are analysed searching for non-conjugacy in the night side sector. By non-conjugate aurora we mean auroral features appearing in one hemisphere only, or significant differences in intensity between the hemispheres for the same auroral feature. We suggest that our observed large scale asymmetries can be explained in terms of inter hemispheric currents (IHC). Coherent with our earlier findings, we list three possible candidates for producing such inter hemispheric currents based on observations. 1) Hemispherical differences in the solar wind dynamo due to IMF Bx and tilt angle producing different strength of region 1 currents in the conjugate he mispheres, 2) Hemispherical differences in conductivity controlled by the tilt angle only giving rise to IHC on closed field lines, and 3) Field-aligned current components induced by the penetration of the IMF By into the closed magnetosphere. Most of the observed non-conjugate aurora in our dataset can be explained by these candidates only. The IMF By penetration candidate is considered closer. We search for evidence in our data that IMF By < 0 (By > 0) can induce an IHC producing stronger aurora on the polar boundary in the Northern (Southern) Hemisphere. Also a second IHC component are predicted from the theory, mapping to the equatorward part of the oval and opposite directed along the magnetic field lines. Using a much larger dataset for one hemisphere only, we show whether these predicted currents can

  18. S-N secular ocean tide: explanation of observably coastal velocities of increase of a global mean sea level and mean sea levels in northern and southern hemispheres and prediction of erroneous altimetry velocities

    NASA Astrophysics Data System (ADS)

    Barkin, Yury

    2010-05-01

    solidification of materials at core-mantle boundary in opposite (northern - southern) hemispheres [7]. 2 Atmospheric and oceanic inversion tides. The gravitational attraction of superfluous mass of the drifting to the North core (in 17 masses of the Moon) causes a planetary inversion tide of air masses of the Earth and its oceanic masses, from the southern hemisphere - to the northern hemisphere [8]. On our theoretical estimations the mean atmospheric pressure in the northern hemisphere accrues with velocity about 0.17 mbar/yr and with similar negative velocity in southern hemisphere. Although mentioned estimations are draft the predicted phenomenon of a slow redistribution of air masses from the southern hemisphere in northern partially has already obtained confirmation according to the meteorological observations in period 1.4. 2002 - 1.4. 2005 [9]: 0.17-0.22 mbar/yr (northern hemisphere) and -0.18 mbar/yr (southern hemisphere). On the basis of modern data of satellite altimetry for 1993-2007 years we for the first time appreciate velocities of secular variations of the mean sea level in northern and southern hemispheres of the Earth which, as well as was supposed, appeared various [10]. In the report the mechanisms of the revealed phenomena, their dynamic interrelation are discussed and an possible interpretation to the data of observations is given. 3 Contrast changes of mean sea levels in northern and southern hemispheres. The air masses slowly are transported from a southern hemisphere in northern. They form an original inversion secular atmospheric tide which existence proves to be true by the modern data of observations [9-11]. The gravitational attraction of the core which is displaced along a polar axis causes the similar tide of oceanic masses [5]. The barometric effect of influence of atmospheric tide will result in reduction of expected secular oceanic tide. Really, an increase of mean atmospheric pressure in the northern hemisphere results in replacement of oceanic

  19. The Low-Degree Shape of Mercury

    NASA Astrophysics Data System (ADS)

    Perry, M. E.; Neumann, G. A.; Mazarico, E.; Hauck, S. A., II; Solomon, S. C.; Zuber, M. T.; Smith, D. E.; Phillips, R. J.; Margot, J. L.; Johnson, C. L.; Ernst, C. M.; Oberst, J.

    2015-12-01

    The shape of Mercury, particularly when combined with its geoid, provides clues to the planet's internal structure, thermal evolution, and rotational history. Twenty-five million elevation measurements of the northern hemisphere, acquired by the Mercury Laser Altimeter on the MErcury Surface, Space ENvironment, GEochemistry, and Ranging spacecraft, were combined with 378 occultation measurements of radio-frequency signals from the spacecraft in the planet's southern hemisphere to reveal the low-degree shape of Mercury. We solved for the spherical-harmonic coefficients through degree and order 128 and found that Mercury's mean radius is 2439.36±0.02 km. The offset between the planet's centers of mass and figure is negligible (40±40 m) along the polar axis and modest (140±50 m) in the equatorial plane. Mercury's spherical-harmonic shape spectrum is dominated by degree 2, and the planet's first-order shape is that of a triaxial ellipsoid with semimajor axes a, b, and c. The polar radius, c, is 1.65 km less than (a+b)/2, and the equatorial difference, a-b, is 1.25 km. The long axis is rotated 15° west of Mercury's dynamically defined principal axis. Mercury's geoid is similarly dominated by degree 2 and well described by a triaxial ellipsoid. The degree-2 geoid and shape are highly correlated, but the power spectral density of the geoid at degree 2 is only 1% of its shape counterpart, implying substantial compensation of elevation variations on a global scale and that Mercury is not in hydrostatic equilibrium.

  20. Superordinate Shape Classification Using Natural Shape Statistics

    ERIC Educational Resources Information Center

    Wilder, John; Feldman, Jacob; Singh, Manish

    2011-01-01

    This paper investigates the classification of shapes into broad natural categories such as "animal" or "leaf". We asked whether such coarse classifications can be achieved by a simple statistical classification of the shape skeleton. We surveyed databases of natural shapes, extracting shape skeletons and tabulating their…

  1. Experience-dependent hemispheric specialization of letters and numbers is revealed in early visual processing.

    PubMed

    Park, Joonkoo; Chiang, Crystal; Brannon, Elizabeth M; Woldorff, Marty G

    2014-10-01

    Recent fMRI research has demonstrated that letters and numbers are preferentially processed in distinct regions and hemispheres in the visual cortex. In particular, the left visual cortex preferentially processes letters compared with numbers, whereas the right visual cortex preferentially processes numbers compared with letters. Because letters and numbers are cultural inventions and are otherwise physically arbitrary, such a double dissociation is strong evidence for experiential effects on neural architecture. Here, we use the high temporal resolution of ERPs to investigate the temporal dynamics of the neural dissociation between letters and numbers. We show that the divergence between ERP traces to letters and numbers emerges very early in processing. Letters evoked greater N1 waves (latencies 140-170 msec) than did numbers over left occipital channels, whereas numbers evoked greater N1s than letters over the right, suggesting letters and numbers are preferentially processed in opposite hemispheres early in visual encoding. Moreover, strings of letters, but not single letters, elicited greater P2 ERP waves (starting around 250 msec) than numbers did over the left hemisphere, suggesting that the visual cortex is tuned to selectively process combinations of letters, but not numbers, further along in the visual processing stream. Additionally, the processing of both of these culturally defined stimulus types differentiated from similar but unfamiliar visual stimulus forms (false fonts) even earlier in the processing stream (the P1 at 100 msec). These findings imply major cortical specialization processes within the visual system driven by experience with reading and mathematics.

  2. Numerical Investigation on the High-Speed Water-Entry Behaviors of Cylindrical, Hemispherical and Conical Projectiles

    NASA Astrophysics Data System (ADS)

    Guo, Zi-Tao; Zhang, Wei; Xiao, Xin-Ke

    2009-06-01

    The water entry problem is considered as a classic problem which has a research history of more than 70 years, the water-entry process for projectiles with different nose will be significant for related application and experimental design. In this paper, a series of numerical simulations were conducted to study the water-entry behaviors of cylindrical, hemispherical and conical projectiles using the coupled Lagrange-Euler technology in hydro-code AUTODYN-2D. The detailed cavity expansion process and the cavity characteristics of three projectiles in the early stages of water-entry were obtained. The effects of the projectile nose shape and the projectile velocity on the cavity shapes were studied. Simultaneously, the laws of velocity attenuations for three projectiles were also proposed in this study. The results show that the influence of the projectile velocity on the cavity thickness is much larger than that of the projectile nose shapes, but compared with the effect on the cavity length, the nose shape influence shows little difference with that of the impact velocity. For an identical initial projectile velocity, the cylindrical projectile decays the fastest underwater followed by conical projectiles and hemispherical projectiles.

  3. A New Look at the Northern Hemisphere Sea Ice Concentration

    NASA Astrophysics Data System (ADS)

    Stern, H.; Fetterer, F.; Fowler, C.

    2005-12-01

    Arctic sea ice extent has decreased over the past 25 years by 7% in winter and 17% in summer, with record or near-record summer lows since 2002. These estimates come from satellite passive microwave (PM) data collected since 1979. In this study we use a new data set of Northern Hemisphere sea ice concentration, derived from weekly operational ice charts (1972-2004) produced by the U.S. National Ice Center (NIC), to re-examine regional variability and trends in Arctic sea ice area and extent. The ice charts through 1994 were quality-checked and converted to EASE-Grid format by the Arctic Climatology Project (2000). Charts for 1995-2004 were converted to EASE-Grid by us. Source data used by NIC to create the charts included visible and infrared satellite imagery, active radar imagery, PM data, aerial reconnaissance, ship and shore observations, buoys, model output, information from foreign ice services, and climatology. The PM data were incorporated into the charts only when all other forms of data were not available. We divide the Arctic and sub-Arctic seas into regions and compare chart-derived monthly sea ice concentration in each region to that derived from PM data. We find that the ice charts give a more realistic depiction of the ice edge, the marginal ice zone, and coastal areas. The PM data have the advantage of being available as a daily product rather than weekly or biweekly. The ice charts for 1995-2004 also include concentrations of multiyear ice, first-year ice, and new ice. We present results of our analysis of these data, as well as calculations of the duration of the ice season in each region, and the variability of the ice edge.

  4. A New Look at the Northern Hemisphere Sea Ice Concentration

    NASA Astrophysics Data System (ADS)

    Stern, H.; Fetterer, F.; Fowler, C.

    2006-12-01

    Arctic sea ice extent has decreased over the past 25 years by 7% in winter and 17% in summer, with record or near-record summer lows since 2002. These estimates come from satellite passive microwave (PM) data collected since 1979. In this study we use a new data set of Northern Hemisphere sea ice concentration, derived from weekly operational ice charts (1972-2004) produced by the U.S. National Ice Center (NIC), to re- examine regional variability and trends in Arctic sea ice area and extent. The ice charts through 1994 were quality-checked and converted to EASE-Grid format by the Arctic Climatology Project (2000). Charts for 1995-2004 were converted to EASE-Grid by us. Source data used by NIC to create the charts included visible and infrared satellite imagery, active radar imagery, PM data, aerial reconnaissance, ship and shore observations, buoys, model output, information from foreign ice services, and climatology. The PM data were incorporated into the charts only when all other forms of data were not available. We divide the Arctic and sub-Arctic seas into regions and compare chart-derived monthly sea ice concentration in each region to that derived from PM data. We find that the ice charts give a more realistic depiction of the ice edge, the marginal ice zone, and coastal areas. The PM data have the advantage of being available as a daily product rather than weekly or biweekly. The ice charts for 1995-2004 also include concentrations of multiyear ice, first-year ice, and new ice. We present results of our analysis of these data, as well as calculations of the duration of the ice season in each region, and the variability of the ice edge.

  5. Projected climate impacts for the amphibians of the western hemisphere

    USGS Publications Warehouse

    Lawler, Joshua J.; Shafer, Sarah L.; Bancroft, Betsy A.; Blaustein, Andrew R.

    2010-01-01

    Given their physiological requirements, limited dispersal abilities, and hydrologically sensitive habitats, amphibians are likely to be highly sensitive to future climatic changes. We used three approaches to map areas in the western hemisphere where amphibians are particularly likely to be affected by climate change. First, we used bioclimatic models to project potential climate-driven shifts in the distribution of 413 amphibian species based on 20 climate simulations for 2071–2100. We summarized these projections to produce estimates of species turnover. Second, we mapped the distribution of 1099 species with restricted geographic ranges. Finally, using the 20 future climate-change simulations, we mapped areas that were consistently projected to receive less seasonal precipitation in the coming century and thus were likely to have altered microclimates and local hydrologies. Species turnover was projected to be highest in the Andes Mountains and parts of Central America and Mexico, where, on average, turnover rates exceeded 60% under the lower of two emissions scenarios. Many of the restricted-range species not included in our range-shift analyses were concentrated in parts of the Andes and Central America and in Brazil's Atlantic Forest. Much of Central America, southwestern North America, and parts of South America were consistently projected to experience decreased precipitation by the end of the century. Combining the results of the three analyses highlighted several areas in which amphibians are likely to be significantly affected by climate change for multiple reasons. Portions of southern Central America were simultaneously projected to experience high species turnover, have many additional restricted-range species, and were consistently projected to receive less precipitation. Together, our three analyses form one potential assessment of the geographic vulnerability of amphibians to climate change and as such provide broad-scale guidance for directing

  6. Meteoroid streams identification amongst 231 Southern hemisphere video meteors

    NASA Astrophysics Data System (ADS)

    Jopek, T. J.; Koten, P.; Pecina, P.

    2010-05-01

    In this study, 231 video meteoroid orbits observed at the Southern hemisphere were searched for streams. Several searches have been made using three D-criteria: DSH, DN and DV. The mutual D-distances were processed by a cluster analysis algorithm based on the single neighbour linking technique. The values of the meteoroid association thresholds for groups of 2, 3, 4, ... members were estimated by the statistical approach. In all three basic searches, about 29-33 per cent of the meteoroid sample turned out to belong to the stream component. The following streams have been detected: η Aquariids (ETA, #31), χ Capricornids (CCA, #420), May Microscopiids (MMI, #421), Northern and Southern Librids-Luppids (NLL, #422 SLL, #423) and Northern and Southern May Ophiuchids (NOP, #149 SOP, #150). 12 η Aquariids were detected using each D-function. Their mean orbital elements resemble the orbit of 1P/Haley however, the mean semimajor axis and the activity time differ significantly from those determined by the other observers. 10 members of χ Capricornids and five members of May Microscopiids were found using the DN function only. For these streams, we did not find any counterparts among the streams listed in the IAU MDC. Our Librids-Luppids and Ophiuchids form two separate complex groups which consist of 16 and 18 members, respectively. From a viewpoint of the cluster analysis technique, they are reliable significant structures. Our Ophiuchids are similar to the already known Northern and Southern May Ophiuchids. Near the mean radiant of Librids-Luppids, we do not see any radiant of the known shower. Its possible counterpart, the Southern ω Scorpiids, has a radiant significantly shifted from our Librids-Luppids. Thus, we consider Librids-Luppids as a new stream or some new manifestation of the May Ophiuchids Complex. Also, this study has shown us that in case of complex structures, traditional procedures of meteor showers distinction are not sufficient tool to give

  7. Lateralised motor control: hemispheric damage and the loss of deftness

    PubMed Central

    Hanna-Pladdy, B; Mendoza, J; Apostolos, G; Heilman, K

    2002-01-01

    Objective: To learn if the left compared with the right hemisphere of right handed subjects exerts bilateral compared with contralateral motor control when performing precise and coordinated finger movements. Methods: The study investigated intertask differences of manual motor asymmetries such as speed, precision, and independent finger movements, in patients with unilateral lesions of the left (LHD) or right hemisphere (RHD) and normal controls (C). Results: Normal subjects showed the greatest right hand preference on a task that required rapid coordinated and precise independent finger movements (coin rotation). Both hemisphere damaged groups revealed contralateral motor deficits, but the magnitudes of asymmetries were found to be significantly different (RHD>C>LHD) with contralateral and ipsilateral deficits for LHD subjects. The greatest ipsilateral deficits for the LHD subjects were on those tasks that require precision (grooved pegboard and coin rotation). Conclusions: The degree of hemispheric specialisation is, in part, dependent upon the nature of the motor task, with left hemisphere motor control necessary for tasks that require precision and coordinated independent finger movements. PMID:12397154

  8. Apraxia and spatial inattention dissociate in left hemisphere stroke.

    PubMed

    Timpert, David C; Weiss, Peter H; Vossel, Simone; Dovern, Anna; Fink, Gereon R

    2015-10-01

    Theories of lateralized cognitive functions propose a dominance of the left hemisphere for motor control and of the right hemisphere for spatial attention. Accordingly, spatial attention deficits (e.g., neglect) are more frequently observed after right-hemispheric stroke, whereas apraxia is a common consequence of left-hemispheric stroke. Clinical reports of spatial attentional deficits after left hemisphere (LH) stroke also exist, but are often neglected. By applying parallel analysis (PA) and voxel-based lesion-symptom mapping (VLSM) to data from a comprehensive neuropsychological assessment of 74 LH stroke patients, we here systematically investigate the relationship between spatial inattention and apraxia and their neural bases. PA revealed that apraxic (and language comprehension) deficits loaded on one common component, while deficits in attention tests were explained by another independent component. Statistical lesion analyses with the individual component scores showed that apraxic (and language comprehension) deficits were significantly associated with lesions of the left superior longitudinal fascicle (SLF). Data suggest that in LH stroke spatial attention deficits dissociate from apraxic (and language comprehension) deficits. These findings contribute to models of lateralised cognitive functions in the human brain. Moreover, our findings strongly suggest that LH stroke patients should be assessed systematically for spatial attention deficits so that these can be included in their rehabilitation regime.

  9. Significance of Hemispheric Security for Mexico

    DTIC Science & Technology

    2007-11-02

    control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) 07-04-2003 2. REPORT TYPE 3. DATES COVERED (FROM - TO...has impacted the balance of power among nations. All countries have had to face the social , economic, and political effects of this transformation...mainly without social protection nets, has caused the rich ones to become richer and the poor ones to become poorer. According to ECLAC, the region will

  10. Two distinct forms of functional lateralization in the human brain

    PubMed Central

    Gotts, Stephen J.; Jo, Hang Joon; Wallace, Gregory L.; Saad, Ziad S.; Cox, Robert W.; Martin, Alex

    2013-01-01

    The hemispheric lateralization of certain faculties in the human brain has long been held to be beneficial for functioning. However, quantitative relationships between the degree of lateralization in particular brain regions and the level of functioning have yet to be established. Here we demonstrate that two distinct forms of functional lateralization are present in the left vs. the right cerebral hemisphere, with the left hemisphere showing a preference to interact more exclusively with itself, particularly for cortical regions involved in language and fine motor coordination. In contrast, right-hemisphere cortical regions involved in visuospatial and attentional processing interact in a more integrative fashion with both hemispheres. The degree of lateralization present in these distinct systems selectively predicted behavioral measures of verbal and visuospatial ability, providing direct evidence that lateralization is associated with enhanced cognitive ability. PMID:23959883

  11. Shape memory metals. Final report

    SciTech Connect

    Dworak, T.D.

    1993-09-01

    The ability to define a manufacturing process to form, heat-treat, and join parts made of nickel-titanium and/or copper-zinc-aluminum shape memory alloys was investigated. The specific emphasis was to define a process that would produce shape memory alloy parts in the configuration of helical coils emulating the appearance of compression springs. In addition, the mechanical strength of the finished parts along with the development of a electrical lead attachment method using shape memory alloy wire was investigated.

  12. Trends in Northern Hemisphere surface cyclone frequency and intensity

    USGS Publications Warehouse

    McCabe, G.J.; Clark, M.P.; Serreze, M.C.

    2001-01-01

    One of the hypothesized effects of global warming from increasing concentrations of greenhouse gases is a change in the frequency and/or intensity of extratropical cyclones. In this study, winter frequencies and intensities of extratropical cyclones in the Northern Hemisphere for the period 1959-97 are examined to determine if identifiable trends are occurring. Results indicate a statistically significant decrease in midlatitude cyclone frequency and a significant increase in high-latitude cyclone frequency. In addition, storm intensity has increased in both the high and midlatitudes. The changes in storm frequency correlate with changes in winter Northern Hemisphere temperature and support hypotheses that global warming may result in a northward shift of storm tracks in the Northern Hemisphere.

  13. The reliability of global and hemispheric surface temperature records

    NASA Astrophysics Data System (ADS)

    Jones, Philip

    2016-03-01

    The purpose of this review article is to discuss the development and associated estimation of uncertainties in the global and hemispheric surface temperature records. The review begins by detailing the groups that produce surface temperature datasets. After discussing the reasons for similarities and differences between the various products, the main issues that must be addressed when deriving accurate estimates, particularly for hemispheric and global averages, are then considered. These issues are discussed in the order of their importance for temperature records at these spatial scales: biases in SST data, particularly before the 1940s; the exposure of land-based thermometers before the development of louvred screens in the late 19th century; and urbanization effects in some regions in recent decades. The homogeneity of land-based records is also discussed; however, at these large scales it is relatively unimportant. The article concludes by illustrating hemispheric and global temperature records from the four groups that produce series in near-real time.

  14. Cassini Imaging of Saturn: Southern Hemisphere Winds and Vortices

    NASA Technical Reports Server (NTRS)

    Vasavada, A. R.; Horst, S. M.; Kennedy, M. R.; Ingersoll, A. P.; Porco, C. C.; DelGenio, A. D.; West, R. A.

    2006-01-01

    High-resolution images of Saturn's southern hemisphere acquired by the Cassini Imaging Science Subsystem between February and October 2004 are used to create maps of cloud morphology at several wavelengths, to derive zonal winds, and to characterize the distribution, frequency, size, morphology, color, behavior, and lifetime of vortices. Nonequatorial wind measurements display only minor differences from those collected since 1981 and reveal a strong, prograde flow near the pole. The region just southward of the velocity minimum at 40.7 deg S is especially active, containing numerous vortices, some generated in the proximity of convective storms. The two eastward jets nearest the pole display periodicity in their longitudinal structure, but no direct analogs to the northern hemisphere's polar hexagon or ribbon waves were observed. Characteristics of winds and vortices are compared with those of Saturn's northern hemisphere and Jupiter's atmosphere.

  15. An asymmetric inhibition model of hemispheric differences in emotional processing

    PubMed Central

    Grimshaw, Gina M.; Carmel, David

    2014-01-01

    Two relatively independent lines of research have addressed the role of the prefrontal cortex in emotional processing. The first examines hemispheric asymmetries in frontal function; the second focuses on prefrontal interactions between cognition and emotion. We briefly review each perspective and highlight inconsistencies between them. We go on to describe an alternative model that integrates approaches by focusing on hemispheric asymmetry in inhibitory executive control processes. The asymmetric inhibition model proposes that right-lateralized executive control inhibits processing of positive or approach-related distractors, and left-lateralized control inhibits negative or withdrawal-related distractors. These complementary processes allow us to maintain and achieve current goals in the face of emotional distraction. We conclude with a research agenda that uses the model to generate novel experiments that will advance our understanding of both hemispheric asymmetries and cognition-emotion interactions. PMID:24904502

  16. Brain hemisphere dominance and vocational preference: a preliminary analysis.

    PubMed

    Szirony, Gary Michael; Pearson, L Carolyn; Burgin, John S; Murray, Gerald C; Elrod, Lisa Marie

    2007-01-01

    Recent developments in split-brain theory add support to the concept of specialization within brain hemispheres. Holland's vocational personality theory may overlap with Human Information Processing (HIP) characteristics. Holland's six RIASEC codes were developed to identify vocational personality characteristics, and HIP scales were designed to measure hemispheric laterality. Relationships between the two scales were evaluated through canonical correlation with some significant results, however not all Holland scale scores correlated with left, right, or integrated hemispheric preference. Additional findings related to participants self-perception of music and math ability were also correlated. Findings on this added analysis revealed a high correlation between perception of musical ability and right brain function but not between mathematical concept and left brain alone. Implications regarding vocational choice and work are discussed.

  17. Hemispheric lateralization of singing after intracarotid sodium amylobarbitone1

    PubMed Central

    Gordon, H. W.; Bogen, J. E.

    1974-01-01

    Hemispheric lateralization of singing was investigated in patients who had transient hemiplegia after intracarotid injection of sodium amylobarbitone. It was found that after right carotid injection singing was markedly deficient, whereas speech remained relatively intact. Songs were sung in a monotone, devoid of correct pitch rendering; rhythm was much less affected. By contrast, singing was less disturbed than speech after left carotid injection. The observations indicated a double dissociation; the right hemisphere contributed more for singing, whereas the left demonstrated its usual dominance for speech. A model is proposed that encompasses audible stimuli as well as tactual or visual into a scheme of functional lateralization wherein the right hemisphere specializes in processing a complete, time-independent stimulus configuration and the left in a series of successive, time-dependent units. PMID:4844140

  18. Hypothalamic digoxin, hemispheric chemical dominance, and addictive behavior.

    PubMed

    Kurup, Ravi Kumar; Kurup, Parameswara Achutha

    2003-02-01

    The isoprenoid pathway produces an endogenous membrane sodium-potassium ATPase inhibitor, digoxin. Digoxin can regulate neurotransmitter transport in the brain with upregulation of tryptophan transport over tyrosine. The pathway was assessed in individuals with addiction, as well as in those with differing hemispheric dominance. The isoprenoid pathway was upregulated with increased digoxin synthesis in addiction. There was an increase in tryptophan catabolites--quinolinic acid, serotonin, nicotine, and strychnine--in patients with addiction, and a reduction in tyrosine catabolites--dopamine, noradrenatine, and morphine. The pattern seen in addiction individuals was similar to that in right hemispheric chemical dominance. Addiction represents a state of right hemispheric chemical dominance, hyperdigoxinemia, and endogenous morphine deficiency state.

  19. Asymmetric field-aligned currents in the conjugate hemispheres

    NASA Astrophysics Data System (ADS)

    Reistad, J. P.; Ostgaard, N.; Oksavik, K.; Laundal, K. M.

    2012-12-01

    Earlier studies using simultaneous imaging from space of the Aurora Borealis (Northern Hemisphere) and Aurora Australis (Southern Hemisphere) have revealed that the aurora can experience a high degree of asymmetry between the two hemispheres. Using 19 hours of simultaneous global imaging from both hemispheres (IMAGE satellite in north and Polar satellite in south) in conjunction with the entire IMAGE WIC database, we investigate the importance of various mechanisms thought to generate the asymmetries seen in global imaging. In terms of asymmetric or interhemispheric field-aligned currents, three candidate mechanisms have been suggested: 1) Hemispheric differences in solar wind dynamo efficiency mainly controlled by IMF Bx leading to asymmetric region 1 currents; 2) conductivity differences in conjugate areas; and 3) penetration of IMF By into the closed magnetosphere possibly generating a pair of oppositely directed interhemispheric currents. From the 19 hour conjugate dataset we find that the solar wind dynamo is likely to be the most important controlling mechanism for asymmetric bright aurora in the polar part of the nightside oval. Here we present statistical analyses of candidates 1) and 3). Using the entire IMAGE WIC database, a statistical analysis of the auroral brightness distribution along and across the Northern Hemisphere oval is carried out. For each candidate, two extreme cases (+/- IMF Bx for 1) and +/- IMF By for 3)) are compared during times non-favorable for the other two mechanisms. Our results indicate that solar wind dynamo induced currents play an important role for the nightside auroral brightness in an average sense. Also, signatures of interhemispheric currents due to IMF By penetration are seen in our statistics, although this effect is somehow weaker.

  20. Lack of hemispheric dominance for consciousness in acute ischaemic stroke

    PubMed Central

    Cucchiara, B; Kasner, S; Wolk, D; Lyden, P; Knappertz, V; Ashwood, T; Odergren, T; Nordlund, A

    2003-01-01

    Background: Previous reports have suggested left hemispheric dominance for maintaining consciousness, although there is controversy over this claim. Objective: To compare early impairment of level of consciousness between patients with right and left hemispheric stroke. Methods: Data from 564 patients with ischaemic stroke enrolled in the placebo arm of a trial of a putative neuroprotectant were analysed. All patients had major hemispheric stroke with cortical dysfunction, visual field deficit, and limb weakness, with symptom onset within 12 hours of enrolment. Patients were prospectively evaluated on a predefined scale (1–6; 1 = fully awake, higher scores representing greater impairment) to measure level of consciousness at multiple time points over the initial 24 hours after presentation. The National Institutes of Health (NIH) stroke scale score at presentation and infarct volume at 30 days were determined. Results: Some degree of impairment in level of consciousness was observed in 409 of the 564 patients (73%). Median maximum sedation score was 2 for both right and left hemispheric stroke (p = 0.91). Mean sedation score over 24 hours was 1.5 for both right and left stroke (p = 0.75). There was no difference between level of consciousness scores in right and left stroke at any individual time point during the 24 hour monitoring period. No association between side and impairment in level of consciousness was seen after adjustment for stroke severity and infarct volume. Conclusions: In contrast to previous reports, there was no evidence for hemispheric dominance for consciousness in the setting of a major hemispheric stroke. PMID:12810773

  1. Geology of the southern hemisphere of Triton: No polar cap

    NASA Technical Reports Server (NTRS)

    Schenk, P.; Moore, J. M.

    1993-01-01

    The bright southern hemisphere, comprising Uhlanga Regio, is perhaps the most poorly understood geologic province on Triton. The entire bright southern hemisphere has been described as a bright polar 'cap', implying a seasonal origin, or as a permanent geologic terrain distinct from the equatorial terrains. Also, thermal models have predicted seasonal migration of frosts and ices from the presently sun-lit south latitudes to the dark northern latitudes. The distribution of frosts and geologic history of this region must be determined observationally. We reexamine the geology of this terrain with the goal of answering these questions.

  2. Volumetric hemispheric ratio as a useful tool in personality psychology.

    PubMed

    Montag, Christian; Schoene-Bake, Jan-Christoph; Wagner, Jan; Reuter, Martin; Markett, Sebastian; Weber, Bernd; Quesada, Carlos M

    2013-02-01

    The present study investigates the link between volumetric hemispheric ratios (VHRs) and personality measures in N=267 healthy participants using Eysenck's Personality Inventory-Revised (EPQ-R) and the BIS/BAS scales. A robust association between extraversion and VHRs was observed for gray matter in males but not females. Higher gray matter volume in the left than in the right hemisphere was associated with higher extraversion in males. The results are discussed in the context of positive emotionality and laterality of the human brain.

  3. Hemispherical radiating pattern antenna design for radio meteor observation

    NASA Astrophysics Data System (ADS)

    Kákona, J.

    2016-01-01

    A highly directional pattern antenna is usually used for radio meteor observations, but these types of antennas became impractical in cases where we have multiple transmitters spread around a reception station. In that situation the hemispherical sensitivity of the antenna is more important than directional antenna gain. We present a hemispherical radiation pattern antenna design which could be modified for almost any observational frequency reflective by a meteor trail. The symmetry of the radiation pattern of such antenna allows an easy construction of antenna arrays which could be used for the angular measurement of received signals.

  4. Plane and hemispherical potential structures in magnetically expanding plasmas

    SciTech Connect

    Takahashi, Kazunori; Igarashi, Yuichi; Fujiwara, Tamiya

    2010-07-26

    Two-dimensional potential structures are measured for different gas pressure in expanding argon plasma using permanent magnets, where the magnetic field is about 100 G in the source and several gauss in the diffusion chamber. The plane potential drop is observed near the source exit for 0.35 mTorr, while the potential structure becomes hemispherical when increasing up to 1 mTorr; the hemispherical structure results in the radial divergence of the ion beam. It is found that the trajectories of the accelerated ions and the electrons overcoming the potential drop are dominated by the potential structure and magnetic-field lines, respectively.

  5. Evolution of Southern Hemisphere spring air masses observed by HALOE

    NASA Technical Reports Server (NTRS)

    Pierce, R. Bradley; Grose, William L.; Russell, James M., III; Tuck, Adrian F.

    1994-01-01

    The evolution of Southern Hemisphere air masses observed by the Halogen Occultation Experiment (HALOE) during September 21 through October 15, 1992, is investigated using isentropic trajectories computed from United Kingdom Meteorological Office (UKMO) assimilated winds and temperatures. Maps of constituent concentrations are obtained by accumulation of air masses from previous HALOE occultations. Lagged correlations between initial and subsequent HALOE observations of the same air mass are used to validate the air mass trajectories. High correlations are found for lag times as large as 10 days. Frequency distributions of the air mass constituent concentrations are used to examine constituent distributions in and around the Southern Hemisphere polar vortex.

  6. Schizophrenia, the sense of 'self' and the right cerebral hemisphere.

    PubMed

    Hecht, David

    2010-01-01

    Schizophrenia is described in phenomenological theory as an illness with various degrees of 'self disintegration' and/or 'disembodiment' experiences. Cognitive neuroscience and neurology had identified specific brain structures, all in the right cerebral hemisphere, that are crucial for the generation of a normal 'sense of self' and self-corporeal-awareness. Behavioral and neuroanatomical evidence also suggest various deficits in the right hemisphere of schizophrenics. A hypothesis is put forth here for a strong linkage and correlation between the specific brain constructs involved in self/corporeal-awareness and the schizophrenic symptoms manifesting the disintegration of the 'self'.

  7. Outlet baffles: Effect on liquid residuals from zero-gravity draining of hemispherically ended cylinders

    NASA Technical Reports Server (NTRS)

    Symons, E. P.

    1972-01-01

    An experimental investigation was conducted to study the relative effectiveness of various outlet baffles in reducing liquid residuals resulting from the draining of hemispherically ended cylindrical tanks in a weightless environment. Three different baffles were employed. The relative effectiveness of each baffle was determined by comparing the results obtained, in the form of liquid residuals, with results for an unbaffled tank. Data indicate that all the baffles tested reduced residuals. Reductions betweem 10 and 60 percent were obtained, depending on baffle geometry and outlfow Weber number.

  8. A hemispheric hetero-core fiber optic tactile sensor for texture and hardness detection

    NASA Astrophysics Data System (ADS)

    Yamazaki, Hiroshi; Nishiyama, Michiko; Watanabe, Kazuhiro

    2016-03-01

    This paper describes a hemispheric tactile sensor based on a hetero-core optical fiber for texture and hardness detection in a small contact area. The hetero-core fiber optic sensors developed in our laboratory have been proved to have several attractive advantages such as high sensitivity to soft bending, immunity to temperature fluctuation and cost-effective scheme. The hemisphere-shaped hetero-core fiber optic tactile sensor converts the applied force into the bending curvature on a hetero-core optical fiber. To evaluate the detection performance of minute-structured rough surface, the proposed sensor was tested for scanning on a cloth with the periodic pattern of 0.74 mm. Additionally, it was confirmed that the sensor was able to detect local hardness distributions of hard plastic lumps which were embedded into silicone rubbers. It was furthermore discussed that the sensor can be applied for precise discrimination of such household objects as several kinds of papers with different texture and hardness.

  9. Design and Verification of a Digital Controller for a 2-Piece Hemispherical Resonator Gyroscope.

    PubMed

    Lee, Jungshin; Yun, Sung Wook; Rhim, Jaewook

    2016-04-20

    A Hemispherical Resonator Gyro (HRG) is the Coriolis Vibratory Gyro (CVG) that measures rotation angle or angular velocity using Coriolis force acting the vibrating mass. A HRG can be used as a rate gyro or integrating gyro without structural modification by simply changing the control scheme. In this paper, differential control algorithms are designed for a 2-piece HRG. To design a precision controller, the electromechanical modelling and signal processing must be pre-performed accurately. Therefore, the equations of motion for the HRG resonator with switched harmonic excitations are derived with the Duhamel Integral method. Electromechanical modeling of the resonator, electric module and charge amplifier is performed by considering the mode shape of a thin hemispherical shell. Further, signal processing and control algorithms are designed. The multi-flexing scheme of sensing, driving cycles and x, y-axis switching cycles is appropriate for high precision and low maneuverability systems. The differential control scheme is easily capable of rejecting the common mode errors of x, y-axis signals and changing the rate integrating mode on basis of these studies. In the rate gyro mode the controller is composed of Phase-Locked Loop (PLL), amplitude, quadrature and rate control loop. All controllers are designed on basis of a digital PI controller. The signal processing and control algorithms are verified through Matlab/Simulink simulations. Finally, a FPGA and DSP board with these algorithms is verified through experiments.

  10. Design and Verification of a Digital Controller for a 2-Piece Hemispherical Resonator Gyroscope

    PubMed Central

    Lee, Jungshin; Yun, Sung Wook; Rhim, Jaewook

    2016-01-01

    A Hemispherical Resonator Gyro (HRG) is the Coriolis Vibratory Gyro (CVG) that measures rotation angle or angular velocity using Coriolis force acting the vibrating mass. A HRG can be used as a rate gyro or integrating gyro without structural modification by simply changing the control scheme. In this paper, differential control algorithms are designed for a 2-piece HRG. To design a precision controller, the electromechanical modelling and signal processing must be pre-performed accurately. Therefore, the equations of motion for the HRG resonator with switched harmonic excitations are derived with the Duhamel Integral method. Electromechanical modeling of the resonator, electric module and charge amplifier is performed by considering the mode shape of a thin hemispherical shell. Further, signal processing and control algorithms are designed. The multi-flexing scheme of sensing, driving cycles and x, y-axis switching cycles is appropriate for high precision and low maneuverability systems. The differential control scheme is easily capable of rejecting the common mode errors of x, y-axis signals and changing the rate integrating mode on basis of these studies. In the rate gyro mode the controller is composed of Phase-Locked Loop (PLL), amplitude, quadrature and rate control loop. All controllers are designed on basis of a digital PI controller. The signal processing and control algorithms are verified through Matlab/Simulink simulations. Finally, a FPGA and DSP board with these algorithms is verified through experiments. PMID:27104539

  11. NO PLIF Study of Hypersonic Transition Over a Discrete Hemispherical Roughness Element

    NASA Technical Reports Server (NTRS)

    Danehy, Paul M.; Bathel, Brett F.; Ivey, Christopher; Inman, Jennifer A.; Jones, Stephen B.

    2009-01-01

    Nitric oxide (NO) planar laser-induced fluorescence (PLIF) has been use to investigate the hypersonic flow over a flat plate with and without a 2-mm (0.08-in) radius hemispherical trip. In the absence of the trip, for all angles of attack and two different Reynolds numbers, the flow was observed to be laminar and mostly steady. Boundary layer thicknesses based on the observed PLIF intensity were measured and compared with a CFD computation, showing agreement. The PLIF boundary layer thickness remained constant while the NO flowrate was varied by a factor of 3, indicating non-perturbative seeding of NO. With the hemispherical trip in place, the flow was observed to be laminar but unsteady at the shallowest angle of attack and lowest Reynolds number and appeared vigorously turbulent at the steepest angle of attack and highest Reynolds number. Laminar corkscrew-shaped vortices oriented in the streamwise direction were frequently observed to transition the flow to more turbulent structures.

  12. Southern hemisphere sand furrows: spatial patterning and implications for the cryo-venting process.

    NASA Astrophysics Data System (ADS)

    Nash, Ciaran; Bourke, Mary

    2015-04-01

    Carbon dioxide is an important volatile on Mars. Seasonally, atmospheric CO2 condenses as ice on to the Martian surface and sublimates during the spring. Links have been made between a suite of observed surface features and the sublimation of surface CO2 ice; these include spider-like araneiform, gullies, and fans. Sand furrows are one such feature; suggested to form due to the erosive action of pressurised CO2 gas as it escapes through cracks in surficial ice (i.e. cryo-venting, Bourke, 2013). There are significant and important differences between the North and South Hemispheres, particularly in the seasonal CO2 deposits. Previous investigations into the formation and distribution of sand furrows on Mars have concentrated solely on the northern hemisphere. We present a study of furrows in the southern hemisphere which has yielded new data on their distribution and spatial patterning as well as providing insights into the cryo-venting process. A total of 221 dune sites were surveyed over the three Martian years' of available HiRISE data to establish the overall distribution of sand furrows. A more detailed study was carried out at eight sites using data from Mars Year 30. These sites represent a latitudinal sample of dunefields located between 40°S to 72°S. Surficial CO2 ice thickness was estimated using the Mars Climate Database (Millour et al., 2014). Our data show that sand furrows are significantly less numerous in the study region than in the northern hemisphere where data show they occur in 95% of surveyed sites. We found a strong correlation between latitude and furrow distribution. As one progresses polewards from 40°S, furrows become more numerous until 68°S. Furrows were not detected south of 72°S. Carbon dioxide ice thickness has been highlighted as a potentially important factor controlling furrow distribution in the northern hemisphere (Bourke and McGaley-Towle, 2014). Results from our investigation suggest there is a feedback mechanism between

  13. Observations of martian gullies and constraints on potential formation mechanisms. II. The northern hemisphere

    NASA Astrophysics Data System (ADS)

    Heldmann, Jennifer L.; Carlsson, Ella; Johansson, Henrik; Mellon, Michael T.; Toon, Owen B.

    2007-06-01

    The formation process(es) responsible for creating the observed geologically recent gully features on Mars has remained the subject of intense debate since their discovery. We present new data and analysis of northern hemisphere gullies from Mars Global Surveyor data which is used to test the various proposed mechanisms of gully formation. We located 137 Mars Orbiter Camera (MOC) images in the northern hemisphere that contain clear evidence of gully landforms and analyzed these images in combination with Mars Orbiter Laser Altimeter (MOLA) and Thermal Emission Spectrometer (TES) data to provide quantitative measurements of numerous gully characteristics. Parameters we measured include apparent source depth and distribution, vertical and horizontal dimensions, slopes, orientations, and present-day characteristics that affect local ground temperatures. Northern hemisphere gullies are clustered in Arcadia Planitia, Tempe Terra, Acidalia Planitia, and Utopia Planitia. These gullies form in craters (84%), knobby terrain (4%), valleys (3%), other/unknown terrains (9%) and are found on all slope orientations although the majority of gullies are equator-facing. Most gullies (63%) are associated with competent rock strata, 26% are not associated with strata, and 11% are ambiguous. Assuming thermal conductivities derived from TES measurements as well as modeled surface temperatures, we find that 95% of the gully alcove bases with adequate data coverage lie at depths where subsurface temperatures are greater than 273 K and 5% of the alcove bases lie within the solid water regime. The average alcove length is 470 m and the average channel length is 690 m. Based on a comparison of measured gully features with predictions from the various models of gully formation, we find that models involving carbon dioxide, melting ground ice in the upper few meters of the soil, dry landslide, and surface snowmelt are the least likely to describe the formation of the martian gullies. Although

  14. Snout Shape in Extant Ruminants

    PubMed Central

    Tennant, Jonathan P.; MacLeod, Norman

    2014-01-01

    Snout shape is a prominent aspect of herbivore feeding ecology, interacting with both forage selectivity and intake rate. Previous investigations have suggested ruminant feeding styles can be discriminated via snout shape, with grazing and browsing species characterised by ‘blunt’ and ‘pointed’ snouts respectively, often with specification of an ‘intermediate’ sub-grouping to represent ambiguous feeding styles and/or morphologies. Snout shape morphology is analysed here using a geometric morphometric approach to compare the two-dimensional profiles of the premaxilla in ventral aspect for a large sample of modern ruminant species, for which feeding modes are known from secondary criteria. Results suggest that, when browsing and grazing ruminants are classified ecologically based on a range of feeding style indicators, they cannot be discriminated unambiguously on the basis of snout profile shape alone. Profile shapes in our sample form a continuum with substantial overlap between groupings and a diverse range of morphologies. Nevertheless, we obtained an 83.8 percent ratio of correct post hoc feeding style categorisations based on the proximity of projected profile shapes to group centroids in the discriminant space. Accordingly, this procedure for identifying species whose feeding strategy is ‘unknown’ can be used with a reasonable degree of confidence, especially if backed-up by additional information. Based on these results we also refine the definitions of snout shape varieties, taking advantage of the descriptive power that geometric morphometrics offers to characterize the morphological disparities observed. The shape variance exhibited by both browsing and grazing ruminants corresponds strongly to body mass, providing further evidence for an interaction between snout shape, feeding style, and body size evolution. Finally, by exploring the role of phylogenetic similarity in snout shape, we find a slight increase in successful categorisation

  15. Snout shape in extant ruminants.

    PubMed

    Tennant, Jonathan P; MacLeod, Norman

    2014-01-01

    Snout shape is a prominent aspect of herbivore feeding ecology, interacting with both forage selectivity and intake rate. Previous investigations have suggested ruminant feeding styles can be discriminated via snout shape, with grazing and browsing species characterised by 'blunt' and 'pointed' snouts respectively, often with specification of an 'intermediate' sub-grouping to represent ambiguous feeding styles and/or morphologies. Snout shape morphology is analysed here using a geometric morphometric approach to compare the two-dimensional profiles of the premaxilla in ventral aspect for a large sample of modern ruminant species, for which feeding modes are known from secondary criteria. Results suggest that, when browsing and grazing ruminants are classified ecologically based on a range of feeding style indicators, they cannot be discriminated unambiguously on the basis of snout profile shape alone. Profile shapes in our sample form a continuum with substantial overlap between groupings and a diverse range of morphologies. Nevertheless, we obtained an 83.8 percent ratio of correct post hoc feeding style categorisations based on the proximity of projected profile shapes to group centroids in the discriminant space. Accordingly, this procedure for identifying species whose feeding strategy is 'unknown' can be used with a reasonable degree of confidence, especially if backed-up by additional information. Based on these results we also refine the definitions of snout shape varieties, taking advantage of the descriptive power that geometric morphometrics offers to characterize the morphological disparities observed. The shape variance exhibited by both browsing and grazing ruminants corresponds strongly to body mass, providing further evidence for an interaction between snout shape, feeding style, and body size evolution. Finally, by exploring the role of phylogenetic similarity in snout shape, we find a slight increase in successful categorisation when repeating the

  16. EDITORIAL: Northern Hemisphere high latitude climate and environmental change

    NASA Astrophysics Data System (ADS)

    Groisman, Pavel; Soja, Amber

    2007-10-01

    High Northern Hemisphere latitudes are undergoing rapid and significant change associated with climate warming. Climatic change in this region interacts with and affects the rate of the global change through atmospheric circulation, biogeophysical, and biogeochemical feedbacks. Changes in the surface energy balance, hydrologic cycle, and carbon budget feedback to regional and global weather and climate systems. Two-thirds of the Northern Hemisphere high latitude land mass resides in Northern Eurasia (~20% of the global land mass), and this region has undergone sweeping socio-economic change throughout the 20th century. How this carbon-rich, cold region component of the Earth system functions as a regional entity and interacts with and feeds back to the greater global system is to a large extent unknown. To mitigate the deficiencies in understanding these feedbacks, which may in turn hamper our understanding of the global change rates and patterns, an initiative was formed. Three years ago the Northern Eurasia Earth Science Partnership Initiative (NEESPI) was established to address large-scale and long-term manifestations of climate and environmental change in this region. The NEESPI Science Plan and its Executive Summary have been published at the NEESPI web site (neespi.org). Since 2004, NEESPI participants have been able to seed several waves of research proposals to international and national funding agencies and institutions and also contribute to the International Polar Year. Currently, NEESPI is widely recognized and endorsed by several Earth System Science Partnership (ESSP) programmes and projects: the International Geosphere and Biosphere Programme, the World Climate Research Programme through the Global Energy and Water Cycle Experiment and Climate and Cryosphere Projects, the Global Water System Project, Global Carbon Project, Global Land Project, and the Integrated Land Ecosystem—Atmosphere Processes Study. Through NEESPI, more than 100 individually

  17. Multiple arcs and Pc5 pulsations in the postnoon sector: an inter- hemispheric conjugate observation

    NASA Astrophysics Data System (ADS)

    Yang, H.; Moen, J.; Sato, N.; Hu, H.; Liu, R.; Kikuchi, M.; Zhou, X.; Sakurai, T.; Makita, K.

    Massive statistics with satellite observations shown that there exists an auroral occurrence peak around 1500MLT, which has thus been named as '15MLT hot spot'. Chinese Zhongshan Station (69.37°S, 76.38°E, invariant latitude -74.49° in Antarctica locates on the passage of this 'hot spot' region and its magnetically conjugate point falls around Svalbard in the northern hemisphere. All sky TV observations there have confirmed this auroral peak and found that m ltiple arcu aurora is one of well appearing auroral forms in this region, of which the occurring mechanism is still in many debates. An inter-hemispheric study of a multiple arc aurora event happened on 27 May, 1997, is presented in this paper, where ground observations of Zhongshan are compared with simultaneous ground observations of the IMAGE magnetometer network and ones onboard satellites close its conjugate location. Pc5 pulsations in IMAGE magnetometers and the Geotail satellite magnetometer observations appeared simu ltaneously with multiple arc aurora in Zhongshan's all sky TV observation in the postnoon sector. `Bright spots' auroral activity in the POLAR UV images covering the northern hemisphere can be mapped to the conjugate counterpart of the southern multiple arc activity. Brightenings on multiple auroral arcs were found to swap westward/noonward in the Zhongshan all sky image sequence. This observation seems to offer a new fact favor the kinetic Alfven wave hypothesis for the multiple arc formation, in which MHD surface waves caused by intensive K-H instability are attributed to generate kinetic Alfven waves which can propagate across field lines, activate arcs on different field lines and form multiple arc aurora.

  18. Emotional Valence and Arousal Effects on Memory and Hemispheric Asymmetries

    ERIC Educational Resources Information Center

    Mneimne, Malek; Powers, Alice S.; Walton, Kate E.; Kosson, David S.; Fonda, Samantha; Simonetti, Jessica

    2010-01-01

    This study examined predictions based upon the right hemisphere (RH) model, the valence-arousal model, and a recently proposed integrated model (Killgore & Yurgelun-Todd, 2007) of emotion processing by testing immediate recall and recognition memory for positive, negative, and neutral verbal stimuli among 35 right-handed women. Building upon…

  19. Gender Differences in Empathy: The Role of the Right Hemisphere

    ERIC Educational Resources Information Center

    Rueckert, Linda; Naybar, Nicolette

    2008-01-01

    The relationship between activation of the right cerebral hemisphere (RH) and empathy was investigated. Twenty-two men and 73 women participated by completing a chimeric face task and empathy questionnaire. For the face task, participants were asked to pick which of the two chimeric faces looked happier. Both men and women were significantly more…

  20. Hemispheric Differences in the Recruitment of Semantic Processing Mechanisms

    ERIC Educational Resources Information Center

    Kandhadai, Padmapriya; Federmeier, Kara D.

    2010-01-01

    This study examined how the two cerebral hemispheres recruit semantic processing mechanisms by combining event-related potential measures and visual half-field methods in a word priming paradigm in which semantic strength and predictability were manipulated using lexically associated word pairs. Activation patterns on the late positive complex…

  1. Reading the Wrong Way with the Right Hemisphere

    PubMed Central

    Waldie, Karen E.; Haigh, Charlotte E.; Badzakova-Trajkov, Gjurgjica; Buckley, Jude; Kirk, Ian J.

    2013-01-01

    Reading is a complex process, drawing on a variety of brain functions in order to link symbols to words and concepts. The three major brain areas linked to reading and phonological analysis include the left temporoparietal region, the left occipitotemporal region and the inferior frontal gyrus. Decreased activation of the left posterior language system in dyslexia is well documented but there is relatively limited attention given to the role of the right hemisphere. The current study investigated differences in right and left hemisphere activation between individuals with dyslexia and non-impaired readers in lexical decision tasks (regular words, irregular words, pseudowords) during functional Magnetic Resonance Imaging (fMRI). Results revealed the expected hypo-activation in the left posterior areas in those with dyslexia but also areas of overactivation in the right hemisphere. During pseudoword decisions, for example, adults with dyslexia showed more right inferior occipital gyrus activation than controls. In general the increased activation of left-hemisphere language areas found in response to both regular and pseudowords was absent in dyslexics. Laterality indices showed that while controls showed left lateralised activation of the temporal lobe during lexical decision making, dyslexic readers showed right activation. Findings will inform theories of reading and will have implications for the design of reading interventions. PMID:24961521

  2. Brain Hemispheric Consensus and the Quality of Investment Decisions.

    ERIC Educational Resources Information Center

    Boyd, Michael

    This on-going study explores the hypothesis that stock fund managers who underperform do so because they make bad decisions, and examines whether their choices can be improved by using a decision model that invokes principles of brain hemispheric consensus. The study, begun in fall 1999, involves two groups of business students: the control group…

  3. Brain Hemispheres: Administrators Must Look Also to the Right.

    ERIC Educational Resources Information Center

    Dalili, Farid

    In relating brain hemisphere differences to education and educational administration, the author reviews literature on the issue and discusses the concepts involved. For background, he briefly goes over the history of brain and cognition studies and the advent of "split-brain" studies and the "triune" brain theory. Definitions…

  4. Hemisphere-Dependent Holistic Processing of Familiar Faces

    ERIC Educational Resources Information Center

    Ramon, Meike; Rossion, Bruno

    2012-01-01

    In two behavioral experiments involving lateralized stimulus presentation, we tested whether one of the most commonly used measures of holistic face processing--the composite face effect--would be more pronounced for stimuli presented to the right as compared to the left hemisphere. In experiment 1, we investigated the composite face effect in a…

  5. Hemispheric Differences in Indexical Specificity Effects in Spoken Word Recognition

    ERIC Educational Resources Information Center

    Gonzalez, Julio; McLennan, Conor T.

    2007-01-01

    Variability in talker identity, one type of indexical variation, has demonstrable effects on the speed and accuracy of spoken word recognition. Furthermore, neuropsychological evidence suggests that indexical and linguistic information may be represented and processed differently in the 2 cerebral hemispheres, and is consistent with findings from…

  6. South Hemispheric Teleconnection to Eastern Mediterranean synoptic systems

    NASA Astrophysics Data System (ADS)

    Osetinsky, I.; Alpert, P.

    2009-04-01

    The teleconnections between the Eastern Mediterranean regional climate and large-scaled tropical and midlatitudinal global indices are becoming widely recognized due to the recent publications. We will present the unexpectedly high correlations between the Eastern Mediterranean synoptic system of the Red Sea Trough and global and hemispheric temperature indices. The Red Sea Trough is the pressure pattern originated from the Sudanese Low and stretched over the warm surface of the Red Sea northward, sometimes reaching up to the Western Turkey. We calculated the correlations between the annual number of the Red Sea Trough days over the Eastern Mediterranean region (RST thereafter), and anomalies of the global and northern and southern hemispheric annual temperatures (TG, TNH, TSH, respectively), for 1948-2000. The annual data, both for the RST and for temperatures, were taken unsmoothed. We got the following remarkable correlations: 0.61 between the RST and TG, 0.51 - between RST and TNH, and 0.65 - between RST and TSH. The lower correlation for the Northern Hemisphere (NH), as compared to the Southern Hemisphere (SH), may be explained considering a distribution of continents and oceans. This carries, on the one hand side, a higher NH than SH mankind activity influencing the natural connections, and on the other - an enhanced SH than NH atmospheric circulation.

  7. About Hemispheric Differences in the Processing of Temporal Intervals

    ERIC Educational Resources Information Center

    Grondin, S.; Girard, C.

    2005-01-01

    The purpose of the present study was to identify differences between cerebral hemispheres for processing temporal intervals ranging from .9 to 1.4s. The intervals to be judged were marked by series of brief visual signals located in the left or the right visual field. Series of three (two standards and one comparison) or five intervals (four…

  8. Differential diagnosis of cerebral hemispheric pathology: multimodal approach.

    PubMed

    Moritani, T; Smoker, W R K; Lee, H K; Sato, Y

    2011-06-01

    This article gives a comprehensive review and illustrations of the imaging features of various pathological conditions and clinical syndromes associated with cerebral hemispheric involvement. The various conditions are described and defined to provide a basis for the differential diagnostics. The hypotheses relating to the pathology of the various syndromes are discussed with special emphasis on excitotoxic mechanisms for explaining the subsequent cerebral hemiatrophy.

  9. Versatile optical microscopy using a reconfigurable hemispherical digital condenser

    PubMed Central

    Sen, Sanchari; Molina, Luis; Cao, Dongyu; Desai, Darshan B.; Bernussi, Ayrton A.; Grave de Peralta, Luis

    2015-01-01

    We present a computer-controlled hemispherical digital condenser and demonstrate that a single device can be used to implement a variety of both well established and novel optical microscopy techniques. We verified the condenser capabilities by imaging fabricated periodic patterned structures and biological samples. PMID:25798294

  10. Hemispheric lateralization of motor thresholds in relation to stuttering.

    PubMed

    Alm, Per A; Karlsson, Ragnhild; Sundberg, Madeleine; Axelson, Hans W

    2013-01-01

    Stuttering is a complex speech disorder. Previous studies indicate a tendency towards elevated motor threshold for the left hemisphere, as measured using transcranial magnetic stimulation (TMS). This may reflect a monohemispheric motor system impairment. The purpose of the study was to investigate the relative side-to-side difference (asymmetry) and the absolute levels of motor threshold for the hand area, using TMS in adults who stutter (n = 15) and in controls (n = 15). In accordance with the hypothesis, the groups differed significantly regarding the relative side-to-side difference of finger motor threshold (p = 0.0026), with the stuttering group showing higher motor threshold of the left hemisphere in relation to the right. Also the absolute level of the finger motor threshold for the left hemisphere differed between the groups (p = 0.049). The obtained results, together with previous investigations, provide support for the hypothesis that stuttering tends to be related to left hemisphere motor impairment, and possibly to a dysfunctional state of bilateral speech motor control.

  11. Brain Hemisphericity and Mathematics Achievement of High School Students

    ERIC Educational Resources Information Center

    Fernandez, Sanny F.

    2011-01-01

    This study aimed to find out the brain hemisphericity and mathematics achievement of high school students. The respondents of the study were the 168 first year high school students of Colegio de San Jose, during school year 2010-2011 who were chosen through stratified random sampling. The descriptive and interview methods of research were used in…

  12. Clinical Relevance of Discourse Characteristics after Right Hemisphere Brain Damage

    ERIC Educational Resources Information Center

    Blake, Margaret Lehman

    2006-01-01

    Purpose: Discourse characteristics of adults with right hemisphere brain damage are similar to those reported for healthy older adults, prompting the question of whether changes are due to neurological lesions or normal aging processes. The clinical relevance of potential differences across groups was examined through ratings by speech-language…

  13. Hemispheric Asymmetry and Pun Comprehension: When Cowboys Have Sore Calves

    ERIC Educational Resources Information Center

    Coulson, Seana; Severens, Els

    2007-01-01

    Event-related potentials (ERPs) were recorded as healthy participants listened to puns such as ''During branding, cowboys have sore calves.'' To assess hemispheric differences in pun comprehension, visually presented probes that were either highly related (COW), moderately related (LEG), or unrelated, were presented in either the left or right…

  14. Cross-hemispheric dopamine projections have functional significance

    PubMed Central

    Fox, Megan E.; Mikhailova, Maria A.; Bass, Caroline E.; Takmakov, Pavel; Gainetdinov, Raul R.; Budygin, Evgeny A.; Wightman, R. Mark

    2016-01-01

    Dopamine signaling occurs on a subsecond timescale, and its dysregulation is implicated in pathologies ranging from drug addiction to Parkinson’s disease. Anatomic evidence suggests that some dopamine neurons have cross-hemispheric projections, but the significance of these projections is unknown. Here we report unprecedented interhemispheric communication in the midbrain dopamine system of awake and anesthetized rats. In the anesthetized rats, optogenetic and electrical stimulation of dopamine cells elicited physiologically relevant dopamine release in the contralateral striatum. Contralateral release differed between the dorsal and ventral striatum owing to differential regulation by D2-like receptors. In the freely moving animals, simultaneous bilateral measurements revealed that dopamine release synchronizes between hemispheres and intact, contralateral projections can release dopamine in the midbrain of 6-hydroxydopamine–lesioned rats. These experiments are the first, to our knowledge, to show cross-hemispheric synchronicity in dopamine signaling and support a functional role for contralateral projections. In addition, our data reveal that psychostimulants, such as amphetamine, promote the coupling of dopamine transients between hemispheres. PMID:27298371

  15. Hemispheric Lateralization of Verbal and Spatial Working Memory during Adolescence

    ERIC Educational Resources Information Center

    Nagel, Bonnie J.; Herting, Megan M.; Maxwell, Emily C.; Bruno, Richard; Fair, Damien

    2013-01-01

    Adult functional magnetic resonance imaging (fMRI) literature suggests that a left-right hemispheric dissociation may exist between verbal and spatial working memory (WM), respectively. However, investigation of this type has been obscured by incomparable verbal and spatial WM tasks and/or visual inspection at arbitrary thresholds as means to…

  16. Radar meteor orbital structure of Southern Hemisphere cometary dust streams

    NASA Technical Reports Server (NTRS)

    Baggaley, W. Jack; Taylor, Andrew D.

    1992-01-01

    The Christchurch, New Zealand meteor orbit radar (AMOR) with its high precision and sensitivity, permits studies of the orbital fine structure of cometary streams. PC generated graphics are presented of data on some Southern Hemisphere Streams. Such data can be related to the formation phase and subsequent dynamical processes of dust streams.

  17. Adaptive significance of right hemisphere activation in aphasic language comprehension

    PubMed Central

    Meltzer, Jed A.; Wagage, Suraji; Ryder, Jennifer; Solomon, Beth; Braun, Allen R.

    2013-01-01

    Aphasic patients often exhibit increased right hemisphere activity during language tasks. This may represent takeover of function by regions homologous to the left-hemisphere language networks, maladaptive interference, or adaptation of alternate compensatory strategies. To distinguish between these accounts, we tested language comprehension in 25 aphasic patients using an online sentence-picture matching paradigm while measuring brain activation with MEG. Linguistic conditions included semantically irreversible (“The boy is eating the apple”) and reversible (“The boy is pushing the girl”) sentences at three levels of syntactic complexity. As expected, patients performed well above chance on irreversible sentences, and at chance on reversible sentences of high complexity. Comprehension of reversible non-complex sentences ranged from nearly perfect to chance, and was highly correlated with offline measures of language comprehension. Lesion analysis revealed that comprehension deficits for reversible sentences were predicted by damage to the left temporal lobe. Although aphasic patients activated homologous areas in the right temporal lobe, such activation was not correlated with comprehension performance. Rather, patients with better comprehension exhibited increased activity in dorsal fronto-parietal regions. Correlations between performance and dorsal network activity occurred bilaterally during perception of sentences, and in the right hemisphere during a post-sentence memory delay. These results suggest that effortful reprocessing of perceived sentences in short-term memory can support improved comprehension in aphasia, and that strategic recruitment of alternative networks, rather than homologous takeover, may account for some findings of right hemisphere language activation in aphasia. PMID:23566891

  18. Right Hemisphere Dominance for Emotion Processing in Baboons

    ERIC Educational Resources Information Center

    Wallez, Catherine; Vauclair, Jacques

    2011-01-01

    Asymmetries of emotional facial expressions in humans offer reliable indexes to infer brain lateralization and mostly revealed right hemisphere dominance. Studies concerned with oro-facial asymmetries in nonhuman primates largely showed a left-sided asymmetry in chimpanzees, marmosets and macaques. The presence of asymmetrical oro-facial…

  19. Adaptive significance of right hemisphere activation in aphasic language comprehension.

    PubMed

    Meltzer, Jed A; Wagage, Suraji; Ryder, Jennifer; Solomon, Beth; Braun, Allen R

    2013-06-01

    Aphasic patients often exhibit increased right hemisphere activity during language tasks. This may represent takeover of function by regions homologous to the left-hemisphere language networks, maladaptive interference, or adaptation of alternate compensatory strategies. To distinguish between these accounts, we tested language comprehension in 25 aphasic patients using an online sentence-picture matching paradigm while measuring brain activation with MEG. Linguistic conditions included semantically irreversible ("The boy is eating the apple") and reversible ("The boy is pushing the girl") sentences at three levels of syntactic complexity. As expected, patients performed well above chance on irreversible sentences, and at chance on reversible sentences of high complexity. Comprehension of reversible non-complex sentences ranged from nearly perfect to chance, and was highly correlated with offline measures of language comprehension. Lesion analysis revealed that comprehension deficits for reversible sentences were predicted by damage to the left temporal lobe. Although aphasic patients activated homologous areas in the right temporal lobe, such activation was not correlated with comprehension performance. Rather, patients with better comprehension exhibited increased activity in dorsal fronto-parietal regions. Correlations between performance and dorsal network activity occurred bilaterally during perception of sentences, and in the right hemisphere during a post-sentence memory delay. These results suggest that effortful reprocessing of perceived sentences in short-term memory can support improved comprehension in aphasia, and that strategic recruitment of alternative networks, rather than homologous takeover, may account for some findings of right hemisphere language activation in aphasia.

  20. Does Categorical Perception in the Left Hemisphere Depend on Language?

    ERIC Educational Resources Information Center

    Holmes, Kevin J.; Wolff, Phillip

    2012-01-01

    Categorical perception (CP) refers to the influence of category knowledge on perception and is revealed by a superior ability to discriminate items across categories relative to items within a category. In recent years, the finding that CP is lateralized to the left hemisphere in adults has been interpreted as evidence for a kind of CP driven by…

  1. Hemispheric Cognitive Style: A Comparison of Three Instruments

    ERIC Educational Resources Information Center

    Genovese, Jeremy E. C.

    2005-01-01

    In this study, the author tested the reliability, concurrent validity, and predictive validity of three hemispheric cognitive style instruments: (a) the Preference Test (PT; R. Zenhausern, 1978), (b) the Polarity Questionnaire (PQ; B. E. Morton, 2002), and (c) the Wagner Preference Inventory II (WAPI II; R. F. Wagner & K. A. Wells, 1985).…

  2. Right Hemispheric Dominance in Processing of Unconscious Negative Emotion

    ERIC Educational Resources Information Center

    Sato, Wataru; Aoki, Satoshi

    2006-01-01

    Right hemispheric dominance in unconscious emotional processing has been suggested, but remains controversial. This issue was investigated using the subliminal affective priming paradigm combined with unilateral visual presentation in 40 normal subjects. In either left or right visual fields, angry facial expressions, happy facial expressions, or…

  3. Characterizing the Influence of Hemispheric Transport on Regional Air Pollution

    EPA Science Inventory

    Expansion of the coupled WRF-CMAQ modeling system to hemispheric scales is pursued to enable the development of a robust modeling framework in which the interactions between atmospheric processes occurring at various spatial and temporal scales can be examined in a consistent man...

  4. Complementary hemispheric specialization for language production and visuospatial attention.

    PubMed

    Cai, Qing; Van der Haegen, Lise; Brysbaert, Marc

    2013-01-22

    Language production and spatial attention are the most salient lateralized cerebral functions, and their complementary specialization has been observed in the majority of the population. To investigate whether the complementary specialization has a causal origin (the lateralization of one function causes the opposite lateralization of the other) or rather is a statistical phenomenon (different functions lateralize independently), we determined the lateralization for spatial attention in a group of individuals with known atypical right hemispheric (RH) lateralization for speech production, based on a previous large-scale screening of left-handers. We show that all 13 participants with RH language dominance have left-hemispheric dominance for spatial attention, and all but one of 16 participants with left-hemispheric language dominance are RH dominant for spatial attention. Activity was observed in the dorsal fronto-parietal pathway of attention, including the inferior parietal sulcus and superior parietal lobule, the frontal eye-movement field, and the inferior frontal sulcus/gyrus, and these regions functionally colateralized in the hemisphere dominant for attention, independently of the side of lateralization. Our results clearly support the Causal hypothesis about the complementary specialization, and we speculate that it derives from a longstanding evolutionary origin. We also suggest that the conclusions about lateralization based on an unselected sample of the population and laterality assessment using coarse functional transcranial Doppler sonography should be interpreted with more caution.

  5. Conflicting strategies and hemispheric suppression in a lexical decision task.

    PubMed

    Rutherford, Barbara J; Lutz, Kevin T

    2004-07-01

    The research tests the prediction of the inhibitory-interaction hypothesis that experience with a task accentuates the functional imbalance between the hemispheres. Right-handed males who were experienced readers were presented a letter string to the centre visual field for lexical decision. The string was or was not accompanied by a blinking light to the left or right visual field. It was predicted that asymmetry would be greatest for strings that spelled words, less for strings that were orthographically correct (pseudowords) and least for strings that were orthographically incorrect (nonwords) because efficient adult readers have more experience with letter strings that do than do not spell a word, and have more experience with orthographically correct than incorrect letter strings. The analysis of response times supported the prediction. Moreover, in the nonword and in early trials of the pseudoword conditions, response times were faster when one or other hemisphere was distracted than when both were engaged suggesting the hemispheres use strategies that conflict when suppression has not been accentuated by practice. As well, as the trials progressed in the pseudoword condition, asymmetry reversed before increasing suggesting that the hemispheres reduce conflict by competing for and then strengthening suppression.

  6. What Does the Right Hemisphere Know about Phoneme Categories?

    ERIC Educational Resources Information Center

    Wolmetz, Michael; Poeppel, David; Rapp, Brenda

    2011-01-01

    Innate auditory sensitivities and familiarity with the sounds of language give rise to clear influences of phonemic categories on adult perception of speech. With few exceptions, current models endorse highly left-hemisphere-lateralized mechanisms responsible for the influence of phonemic category on speech perception, based primarily on results…

  7. Spanish Heritage and Influence in the Western Hemisphere.

    ERIC Educational Resources Information Center

    San Francisco Unified School District, CA.

    This is a selected bibliography of some good and some outstanding audio-visual educational materials in the library of the Educational Materials Bureau, Audio-Visual Educational Section, that may be considered of particular interest in the study of Spanish heritage and influence in the Western Hemisphere. The bibliography is arranged…

  8. Shape-changing shell-like structures.

    PubMed

    Pagitz, M; Bold, J

    2013-03-01

    Plants such as Dionaea muscipula (Venus Flytrap) can change the shape of their shell-like leaves by actively altering the cell pressures. These leaves are hydraulic actuators that do not require any complex controls and that possess an energy efficiency that is unmatched by natural or artificial muscles (Huber et al 1997 Proc. R. Soc. A 453 2185-205). We extend our previous work (Pagitz et al 2012 Bioinspir. Biomim. 7 016007) on pressure-actuated cellular structures by introducing a concept for shape-changing shell-like structures that can significantly alter their Gaussian curvature. The potential of this concept is demonstrated by a hemispherical shell that can reversibly change the sign of its Gaussian curvature. Furthermore, it is shown that a snap-through behaviour, similar to the one known from Dionaea muscipula, can be achieved by lowering the pressure in a single layer of cells.

  9. The equilibrium shape of bubbles on curved interfaces

    NASA Astrophysics Data System (ADS)

    Bird, James; Poe, Daniel; Walls, Peter

    2016-11-01

    The equilibrium shape for a bubble resting at a free surface depends on a balance of hydrostatic and capillary forces, with the smallest bubbles approximating a sphere and a hemisphere for the largest. This shape has been shown to be important to several processes ranging from gas transfer across the thin film cap to the production of jet droplets. Past works calculating the equilibrium shape assume that the interface is flat. However, there are instances where the curvature of the boundary may be comparable to the bubble itself. For example, a bubble bursting on the surface of a rain droplet. Here we relax the assumption of a flat interface and extend the classic bubble shape calculations to account for a curved interface boundary. An understanding of the extent of this deformation and the precise equilibrium bubble shape is important to applications in fields ranging from air-sea exchange to combustion dynamics. We acknowledge financial support from NSF Grant No. 1351466.

  10. A New Sheet Metal Forming System Based on Incremental Punching

    NASA Astrophysics Data System (ADS)

    Luo, Yuanxin

    Stamping is one of the most commonly used manufacturing processes. Everyday, millions of parts are formed by this process. The conventional stamping is to form a part in one or several operations with a press machine and a set/sets of dies. It is very efficient but is not cost effective for small batch production parts and prototypes as the dies are expensive and time consuming to make. Recently, with the increasing demands for low-volume and customer-made products, a die-less forming method, Incremental Sheet Metal Forming (ISMF), has become one of the leading R&D topics in the industry. ISMF uses a small generic tool to apply a sequence of operations along the given path to deform the sheet incrementally. These small deformations accumulate to form the final shape of the part. As a result, different parts can be made by the same setup. Despite of some 30 years of research and development, however, ISMF technology is still premature for industrial applications due to the following reasons: The accuracy of the part is limited; the surface roughness is poor; and the productivity is low. This motivates the presented research. In this research, a new incremental forming system based on incremental punching is designed and built. The system consists of a 3-axes CNC platform, a high speed hydraulic cylinder with a hemispherical forming tool, and a PC-based CNC control system. The hydraulic system provides the forming force to deform the sheet metal with constant stokes, while the CNC system positions the part. When forming a part, the forming tool punches the sheet metal along the given contour of the part punch by punch; when one layer of the part is completed, the forming tool moves down to the next layer; and the process is finished till all layers are completed. The CNC control system works with standard NC code, and hence, is easy to use. In order to ensure the desirable performance of the machine, dynamic analysis of the machine is necessary. The analysis is

  11. Beyond hemispheric dominance: brain regions underlying the joint lateralization of language and arithmetic to the left hemisphere.

    PubMed

    Pinel, Philippe; Dehaene, Stanislas

    2010-01-01

    Language and arithmetic are both lateralized to the left hemisphere in the majority of right-handed adults. Yet, does this similar lateralization reflect a single overall constraint of brain organization, such an overall "dominance" of the left hemisphere for all linguistic and symbolic operations? Is it related to the lateralization of specific cerebral subregions? Or is it merely coincidental? To shed light on this issue, we performed a "colateralization analysis" over 209 healthy subjects: We investigated whether normal variations in the degree of left hemispheric asymmetry in areas involved in sentence listening and reading are mirrored in the asymmetry of areas involved in mental arithmetic. Within the language network, a region-of-interest analysis disclosed partially dissociated patterns of lateralization, inconsistent with an overall "dominance" model. Only two of these areas presented a lateralization during sentence listening and reading which correlated strongly with the lateralization of two regions active during calculation. Specifically, the profile of asymmetry in the posterior superior temporal sulcus during sentence processing covaried with the asymmetry of calculation-induced activation in the intraparietal sulcus, and a similar colateralization linked the middle frontal gyrus with the superior posterior parietal lobule. Given recent neuroimaging results suggesting a late emergence of hemispheric asymmetries for symbolic arithmetic during childhood, we speculate that these colateralizations might constitute developmental traces of how the acquisition of linguistic symbols affects the cerebral organization of the arithmetic network.

  12. Levels of alpha-HCH, lindane, and enantiomeric ratios of alpha-HCH in marine mammals from the northern hemisphere.

    PubMed

    Hummert, K; Vetter, W; Luckas, B

    1995-09-01

    The enantiomeric ratios of alpha-HCH were determined by chiral gas chromatography in blubber of marine mammals from regions of the northern hemisphere (North Sea, Baltic Sea, Arctic and Iceland). Cetaceans (harbour porpoises and white-beaked dolphins) showed a preferential accumulation of (+)-alpha-HCH. In blubber of harbour seals, grey seals and harp seals (+)-alpha-HCH was also more abundant than (-)-alpha-HCH. Hooded seals formed an exception with a (+/-) enantiomeric ratio of alpha-HCH < 1.

  13. Performance evaluation of booster materials in the plastic bonded explosive PBX 9502 in a hemispherical wave breakout test

    SciTech Connect

    Hooks, Daniel E; Morris, John S; Hill, Larry G; Francois, Elizabeth

    2008-01-01

    An explosive booster is normally required to initiate detonation in an insensitive high explosive (lHE). Booster materials must be ignitable by a conventional detonator and deliver sufficient energy and favorable pulse shape to initiate the IHE charge. The explosive booster should be as insensitive as reasonably possible to maintain the overall safety margin of the explosive assembly. A hemispherical wave breakout test termed the on ionskin test is one of the methods of testing the performance of booster materials in an initiation train assembly. There are several variations of this basic test which are known by other names. In this test, the wave breakout time-position history at the surface of a hemispherical IHE acceptor charge is recorded, and the relative uniformity of breakout allows qualitative comparison between booster candidates and quantitative comparison of several metrics. The results of a series of onionskin experiments evaluating the performance of some new booster formulations in the triaminotrinitrobenzene (TA TB) -based plastic bonded explosive PBX 9502 will be presented. The boosters were tested in an onionskin arrangement in which the booster pellet was cylindrical, and the tests were performed at a temperature of-55{sup o}C to emphasize variations in spreading performance. The modification from the traditional hemispherical geometry facilitated efficient explosive fabrication and charge assembly, but the results indicate that this geometry was not ideal for several reasons. Despite the complications arising from geometry, promising performance was observed from booster formulations including 3,3' -diamino-4,4'azoxyfurazan.

  14. Shape memory system with integrated actuation using embedded particles

    DOEpatents

    Buckley, Patrick R [New York, NY; Maitland, Duncan J [Pleasant Hill, CA

    2012-05-29

    A shape memory material with integrated actuation using embedded particles. One embodiment provides a shape memory material apparatus comprising a shape memory material body and magnetic pieces in the shape memory material body. Another embodiment provides a method of actuating a device to perform an activity on a subject comprising the steps of positioning a shape memory material body in a desired position with regard to the subject, the shape memory material body capable of being formed in a specific primary shape, reformed into a secondary stable shape, and controllably actuated to recover the specific primary shape; including pieces in the shape memory material body; and actuating the shape memory material body using the pieces causing the shape memory material body to be controllably actuated to recover the specific primary shape and perform the activity on the subject.

  15. Shape memory system with integrated actuation using embedded particles

    DOEpatents

    Buckley, Patrick R; Maitland, Duncan J

    2014-04-01

    A shape memory material with integrated actuation using embedded particles. One embodiment provides a shape memory material apparatus comprising a shape memory material body and magnetic pieces in the shape memory material body. Another embodiment provides a method of actuating a device to perform an activity on a subject comprising the steps of positioning a shape memory material body in a desired position with regard to the subject, the shape memory material body capable of being formed in a specific primary shape, reformed into a secondary stable shape, and controllably actuated to recover the specific primary shape; including pieces in the shape memory material body; and actuating the shape memory material body using the pieces causing the shape memory material body to be controllably actuated to recover the specific primary shape and perform the activity on the subject.

  16. Shape memory system with integrated actuation using embedded particles

    DOEpatents

    Buckley, Patrick R.; Maitland, Duncan J.

    2009-09-22

    A shape memory material with integrated actuation using embedded particles. One embodiment provides a shape memory material apparatus comprising a shape memory material body and magnetic pieces in the shape memory material body. Another embodiment provides a method of actuating a device to perform an activity on a subject comprising the steps of positioning a shape memory material body in a desired position with regard to the subject, the shape memory material body capable of being formed in a specific primary shape, reformed into a secondary stable shape, and controllably actuated to recover the specific primary shape; including pieces in the shape memory material body; and actuating the shape memory material body using the pieces causing the shape memory material body to be controllably actuated to recover the specific primary shape and perform the activity on the subject.

  17. Role of inter-hemispheric transfer in generating visual evoked potentials in V1-damaged brain hemispheres.

    PubMed

    Kavcic, Voyko; Triplett, Regina L; Das, Anasuya; Martin, Tim; Huxlin, Krystel R

    2015-02-01

    Partial cortical blindness is a visual deficit caused by unilateral damage to the primary visual cortex, a condition previously considered beyond hopes of rehabilitation. However, recent data demonstrate that patients may recover both simple and global motion discrimination following intensive training in their blind field. The present experiments characterized motion-induced neural activity of cortically blind (CB) subjects prior to the onset of visual rehabilitation. This was done to provide information about visual processing capabilities available to mediate training-induced visual improvements. Visual Evoked Potentials (VEPs) were recorded from two experimental groups consisting of 9 CB subjects and 9 age-matched, visually-intact controls. VEPs were collected following lateralized stimulus presentation to each of the 4 visual field quadrants. VEP waveforms were examined for both stimulus-onset (SO) and motion-onset (MO) related components in postero-lateral electrodes. While stimulus presentation to intact regions of the visual field elicited normal SO-P1, SO-N1, SO-P2 and MO-N2 amplitudes and latencies in contralateral brain regions of CB subjects, these components were not observed contralateral to stimulus presentation in blind quadrants of the visual field. In damaged brain hemispheres, SO-VEPs were only recorded following stimulus presentation to intact visual field quadrants, via inter-hemispheric transfer. MO-VEPs were only recorded from damaged left brain hemispheres, possibly reflecting a native left/right asymmetry in inter-hemispheric connections. The present findings suggest that damaged brain hemispheres contain areas capable of responding to visual stimulation. However, in the absence of training or rehabilitation, these areas only generate detectable VEPs in response to stimulation of the intact hemifield of vision.

  18. The left hemisphere learns what is right: Hemispatial reward learning depends on reinforcement learning processes in the contralateral hemisphere.

    PubMed

    Aberg, Kristoffer Carl; Doell, Kimberly Crystal; Schwartz, Sophie

    2016-08-01

    Orienting biases refer to consistent, trait-like direction of attention or locomotion toward one side of space. Recent studies suggest that such hemispatial biases may determine how well people memorize information presented in the left or right hemifield. Moreover, lesion studies indicate that learning rewarded stimuli in one hemispace depends on the integrity of the contralateral striatum. However, the exact neural and computational mechanisms underlying the influence of individual orienting biases on reward learning remain unclear. Because reward-based behavioural adaptation depends on the dopaminergic system and prediction error (PE) encoding in the ventral striatum, we hypothesized that hemispheric asymmetries in dopamine (DA) function may determine individual spatial biases in reward learning. To test this prediction, we acquired fMRI in 33 healthy human participants while they performed a lateralized reward task. Learning differences between hemispaces were assessed by presenting stimuli, assigned to different reward probabilities, to the left or right of central fixation, i.e. presented in the left or right visual hemifield. Hemispheric differences in DA function were estimated through differential fMRI responses to positive vs. negative feedback in the left vs. right ventral striatum, and a computational approach was used to identify the neural correlates of PEs. Our results show that spatial biases favoring reward learning in the right (vs. left) hemifield were associated with increased reward responses in the left hemisphere and relatively better neural encoding of PEs for stimuli presented in the right (vs. left) hemifield. These findings demonstrate that trait-like spatial biases implicate hemisphere-specific learning mechanisms, with individual differences between hemispheres contributing to reinforcing spatial biases.

  19. Fabrication of hemispherical liquid encapsulated structures based on droplet molding

    NASA Astrophysics Data System (ADS)

    Ishizuka, Hiroki; Miki, Norihisa

    2015-12-01

    We have developed and demonstrated a method for forming spherical structures of a thin polydimethylsiloxane (PDMS) membrane encapsulating a liquid. Liquid encapsulation can enhance the performance of microelectromechanical systems (MEMS) devices by providing deformability and improved dielectric properties. Parylene deposition and wafer bonding are applied to encapsulate liquid into a MEMS device. In parylene deposition, a parylene membrane is directly formed onto a liquid droplet. However, since the parylene membrane is stiff, the membrane is fragile. Although wafer bonding can encapsulate liquid between two substrates, the surface of the fabricated structure is normally flat. We propose a new liquid encapsulation method by dispensing liquid droplets. At first, a 20 μl PDMS droplet is dispensed on ethylene glycol. A 70 μl glycerin droplet is dispensed into a PDMS casting solution layer. The droplet forms a layer on heated ethylene glycol. Glycerin and ethylene glycol are chosen for their high boiling points. Additionally, a glycerin droplet is dispensed on the layer and surrounded by a thin PDMS casting solution film. The film is baked for 1 h at 75 °C. As the result, a structure encapsulating a liquid in a flexible PDMS membrane is obtained. We investigate the effects of the volume, surface tension, and guide thickness on the shape of the formed structures. We also evaluated the effect of the structure diameter on miniaturization. The structure can be adapted for various functions by changing the encapsulated liquid. We fabricated a stiffness-tunable structure by dispensing a magnetorheoligical fluid droplet with a stiffness that can be changed by an external magnetic field. We also confirmed that the proposed structure can produce stiffness differences that are distinguishable by humans.

  20. Preparation of Hollow N-Chloramine-Functionalized Hemispherical Silica Particles with Enhanced Efficacy against Bacteria in the Presence of Organic Load: Synthesis, Characterization, and Antibacterial Activity.

    PubMed

    Rahma, Hakim; Asghari, Sogol; Logsetty, Sarvesh; Gu, Xiaochen; Liu, Song

    2015-06-03

    The fabrication of highly effective antimicrobial materials is an important strategy for coping with the growing concern of bacterial resistance. In this study, N-chloramine-functionalized hollow hemispherical structures were designed and prepared to examine possible enhancement of antimicrobial performance. Antimicrobial testing was carried out on Gram-negative (Escherichia coli) and Gram-positive (Baccilus Cereus) bacteria in the presence and absence of biological medium. The efficacy of the hollow hemispherical particles functionalized with various N-chloramines in killing bacteria was compared among themselves with that of small organic molecules and spherical particles to investigate the effect of the surface charge, chemical structure, and shape of the particles. Results demonstrated that quaternary ammonium salt or amine functions in the chemical structure enhanced the antimicrobial activity of the particles and made the particles more effective than the small molecules in the presence of biological medium. The importance of particle shape in the killing tests was also confirmed.

  1. Hemispheric asymmetry of visual scene processing in the human brain: evidence from repetition priming and intrinsic activity.

    PubMed

    Stevens, W Dale; Kahn, Itamar; Wig, Gagan S; Schacter, Daniel L

    2012-08-01

    Asymmetrical specialization of cognitive processes across the cerebral hemispheres is a hallmark of healthy brain development and an important evolutionary trait underlying higher cognition in humans. While previous research, including studies of priming, divided visual field presentation, and split-brain patients, demonstrates a general pattern of right/left asymmetry of form-specific versus form-abstract visual processing, little is known about brain organization underlying this dissociation. Here, using repetition priming of complex visual scenes and high-resolution functional magnetic resonance imaging (MRI), we demonstrate asymmetrical form specificity of visual processing between the right and left hemispheres within a region known to be critical for processing of visual spatial scenes (parahippocampal place area [PPA]). Next, we use resting-state functional connectivity MRI analyses to demonstrate that this functional asymmetry is associated with differential intrinsic activity correlations of the right versus left PPA with regions critically involved in perceptual versus conceptual processing, respectively. Our results demonstrate that the PPA comprises lateralized subregions across the cerebral hemispheres that are engaged in functionally dissociable yet complementary components of visual scene analysis. Furthermore, this functional asymmetry is associated with differential intrinsic functional connectivity of the PPA with distinct brain areas known to mediate dissociable cognitive processes.

  2. An invariant shape representation using the anisotropic Helmholtz equation.

    PubMed

    Joshi, A A; Ashrafulla, S; Shattuck, D W; Damasio, H; Leahy, R M

    2012-01-01

    Analyzing geometry of sulcal curves on the human cortical surface requires a shape representation invariant to Euclidean motion. We present a novel shape representation that characterizes the shape of a curve in terms of a coordinate system based on the eigensystem of the anisotropic Helmholtz equation. This representation has many desirable properties: stability, uniqueness and invariance to scaling and isometric transformation. Under this representation, we can find a point-wise shape distance between curves as well as a bijective smooth point-to-point correspondence. When the curves are sampled irregularly, we also present a fast and accurate computational method for solving the eigensystem using a finite element formulation. This shape representation is used to find symmetries between corresponding sulcal shapes between cortical hemispheres. For this purpose, we automatically generate 26 sulcal curves for 24 subject brains and then compute their invariant shape representation. Left-right sulcal shape symmetry as measured by the shape representation's metric demonstrates the utility of the presented invariant representation for shape analysis of the cortical folding pattern.

  3. Theoretical analysis and experimental verification on valve-less piezoelectric pump with hemisphere-segment bluff-body

    NASA Astrophysics Data System (ADS)

    Ji, Jing; Zhang, Jianhui; Xia, Qixiao; Wang, Shouyin; Huang, Jun; Zhao, Chunsheng

    2014-05-01

    Existing researches on no-moving part valves in valve-less piezoelectric pumps mainly concentrate on pipeline valves and chamber bottom valves, which leads to the complex structure and manufacturing process of pump channel and chamber bottom. Furthermore, position fixed valves with respect to the inlet and outlet also makes the adjustability and controllability of flow rate worse. In order to overcome these shortcomings, this paper puts forward a novel implantable structure of valve-less piezoelectric pump with hemisphere-segments in the pump chamber. Based on the theory of flow around bluff-body, the flow resistance on the spherical and round surface of hemisphere-segment is different when fluid flows through, and the macroscopic flow resistance differences thus formed are also different. A novel valve-less piezoelectric pump with hemisphere-segment bluff-body (HSBB) is presented and designed. HSBB is the no-moving part valve. By the method of volume and momentum comparison, the stress on the bluff-body in the pump chamber is analyzed. The essential reason of unidirectional fluid pumping is expounded, and the flow rate formula is obtained. To verify the theory, a prototype is produced. By using the prototype, experimental research on the relationship between flow rate, pressure difference, voltage, and frequency has been carried out, which proves the correctness of the above theory. This prototype has six hemisphere-segments in the chamber filled with water, and the effective diameter of the piezoelectric bimorph is 30mm. The experiment result shows that the flow rate can reach 0.50 mL/s at the frequency of 6 Hz and the voltage of 110 V. Besides, the pressure difference can reach 26.2 mm H2O at the frequency of 6 Hz and the voltage of 160 V. This research proposes a valve-less piezoelectric pump with hemisphere-segment bluff-body, and its validity and feasibility is verified through theoretical analysis and experiment.

  4. 75 FR 5287 - Federal Advisory Committee; Western Hemisphere Institute for Security Cooperation Board of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-02

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF DEFENSE Office of the Secretary Federal Advisory Committee; Western Hemisphere Institute for Security Cooperation... Hemisphere Institute for Security Cooperation Board of Visitors (hereafter referred to as the Board)....

  5. From Shape to Letters.

    ERIC Educational Resources Information Center

    Schiller, Hillel A.

    In order to make letter shape recognition an integral part of perception training, the use of the line in its two basic shapes is proposed. Letter shapes may seem exceedingly complex linear shapes to young minds. Thus instead of instruction in configuration, instruction involving transformational activities to manipulate and create the…

  6. Hemispheric Differences within the Fronto-Parietal Network Dynamics Underlying Spatial Imagery

    PubMed Central

    Sack, Alexander T.; Schuhmann, Teresa

    2012-01-01

    Spatial imagery refers to the inspection and evaluation of spatial features (e.g., distance, relative position, configuration) and/or the spatial manipulation (e.g., rotation, shifting, reorienting) of mentally generated visual images. In the past few decades, psychophysical as well as functional brain imaging studies have indicated that any such processing of spatially coded information and/or manipulation based on mental images (i) is subject to similar behavioral demands and limitations as in the case of spatial processing based on real visual images, and (ii) consistently activates several nodes of widely distributed cortical networks in the brain. These nodes include areas within both, the dorsal fronto-parietal as well as ventral occipito-temporal visual processing pathway, representing the “what” versus “where” aspects of spatial imagery. We here describe evidence from functional brain imaging and brain interference studies indicating systematic hemispheric differences within the dorsal fronto-parietal networks during the execution of spatial imagery. Importantly, such hemispheric differences and functional lateralization principles are also found in the effective brain network connectivity within and across these networks, with a direction of information flow from anterior frontal/premotor regions to posterior parietal cortices. In an attempt to integrate these findings of hemispheric lateralization and fronto-to-parietal interactions, we argue that spatial imagery constitutes a multifaceted cognitive construct that can be segregated in several distinct mental sub processes, each associated with activity within specific lateralized fronto-parietal (sub) networks, forming the basis of the here proposed dynamic network model of spatial imagery. PMID:22754546

  7. Bristol Stool Form Scale

    MedlinePlus

    ... Stool Form Scale Type Description Type 1 Separate hard lumps, like nuts Image Type 2 Sausage-shaped but lumpy Type 3 Like a sausage or snake but with cracks on its surface Type 4 Like a sausage or snake, smooth and soft ...

  8. Hemispheric asymmetry in the processing of Japanese script.

    PubMed

    Hanavan, Kevin; Coney, Jeffrey

    2005-09-01

    The Japanese written language comprises both a logographic (kanji) and a phonetic (kana) script. Patterns of hemispheric asymmetry in the encoding of these scripts have been found to differ. The present study examined the way in which hemispheric differences at the level of orthographic encoding impact at the level of lexical access. A total of 32 participants performed a lexical decision task within an associative priming paradigm across both scripts. The results showed a right visual field advantage for the processing of kana, but no lateralised advantage for kanji stimuli. Patterns of facilitation also differed, with kanji stimuli eliciting a late-developing and eventually stronger priming effect in the left visual field. The results are discussed with reference to the recognition-with-phonology model in the processing of logographic script.

  9. The Energetics of Transient Eddies in the Martian Northern Hemisphere

    NASA Astrophysics Data System (ADS)

    Battalio, Joseph Michael; Szunyogh, Istvan; Lemmon, Mark T.

    2016-10-01

    The energetics of northern hemisphere transient waves in the Mars Analysis Correction Data Assimilation is analyzed. Three periods between the fall and spring equinoxes (Ls=200°-230°, 255°-285°, and 330°-360°) during three Mars Years are selected to exemplify the fall, winter, and spring wave activity. Fall and spring eddy energetics is similar with some inter-annual and inter-seasonal variability, but winter eddy kinetic energy and its transport are strongly reduced in intensity as a result of the solsticial pause in eddy activity. Barotropic energy conversion acts as a sink of eddy kinetic energy throughout the northern hemisphere eddy period with little reduction in amplitude during the solsticial pause. Baroclinic energy conversion acts as a source in fall and spring but disappears during the winter period as a result of the stabilized vertical shear profile of the westerly jet around winter solstice.

  10. Do temporal processes underlie left hemisphere dominance in speech perception?

    PubMed

    Scott, Sophie K; McGettigan, Carolyn

    2013-10-01

    It is not unusual to find it stated as a fact that the left hemisphere is specialized for the processing of rapid, or temporal aspects of sound, and that the dominance of the left hemisphere in the perception of speech can be a consequence of this specialization. In this review we explore the history of this claim and assess the weight of this assumption. We will demonstrate that instead of a supposed sensitivity of the left temporal lobe for the acoustic properties of speech, it is the right temporal lobe which shows a marked preference for certain properties of sounds, for example longer durations, or variations in pitch. We finish by outlining some alternative factors that contribute to the left lateralization of speech perception.

  11. Agents with left and right dominant hemispheres and quantum statistics

    NASA Astrophysics Data System (ADS)

    Ezhov, Alexandr A.; Khrennikov, Andrei Yu.

    2005-01-01

    We present a multiagent model illustrating the emergence of two different quantum statistics, Bose-Einstein and Fermi-Dirac, in a friendly population of individuals with the right-brain dominance and in a competitive population of individuals with the left-brain hemisphere dominance, correspondingly. Doing so, we adduce the arguments that Lefebvre’s “algebra of conscience” can be used in a natural way to describe decision-making strategies of agents simulating people with different brain dominance. One can suggest that the emergence of the two principal statistical distributions is able to illustrate different types of society organization and also to be used in order to simulate market phenomena and psychic disorders, when a switching of hemisphere dominance is involved.

  12. Hemispherical anisotropic patterns of the Earth’s inner core

    PubMed Central

    Mattesini, Maurizio

    2010-01-01

    It has been shown that the Earth’s inner core has an axisymmetric anisotropic structure with seismic waves traveling ∼3% faster along polar paths than along equatorial directions. Hemispherical anisotropic patterns of the solid Earth’s core are rather complex, and the commonly used hexagonal-close-packed iron phase might be insufficient to account for seismological observations. We show that the data we collected are in good agreement with the presence of two anisotropically specular east and west core hemispheres. The detected travel-time anomalies can only be disclosed by a lattice-preferred orientation of a body-centered-cubic iron aggregate, having a fraction of their [111] crystal axes parallel to the Earth’s rotation axis. This is compelling evidence for the presence of a body-centered-cubic Fe phase at the top of the Earth’s inner core. PMID:20457937

  13. Left face matching bias: right hemisphere dominance or scanning habits?

    PubMed

    Megreya, Ahmed M; Havard, Catriona

    2011-01-01

    A large body of work report a leftward bias in face processing. However, it is not clear whether this leftward bias purely reflects the dominance of the right hemisphere or is influenced by scanning habits developed by reading directions. Here, we report two experiments examining how well native readers of right to left Arabic scripts (Egyptians) could match (for identity) a target face that appeared with a companion to a line-up of 10 faces. There was a significant advantage for matching faces that appeared on the left. However, Experiment 2 found that the magnitude of this left face matching bias was almost three times weaker than the magnitude of the leftward bias shown by native readers of left to right English scripts (British). Accordingly, we suggest that the right hemisphere dominance for face processing underlies the leftward face perception bias, but with the interaction of scanning habits.

  14. Right hemisphere involvement in non-fluent primary progressive aphasia.

    PubMed

    Repetto, Claudia; Manenti, Rosa; Cotelli, Maria; Calabria, Marco; Zanetti, Orazio; Borroni, Barbara; Padovani, Alessandro; Miniussi, Carlo

    2007-01-01

    We described a 56-years-old man with a diagnosis of "non-fluent primary progressive aphasia" (NfPPA). An accurate neuropsychological, neurological and neuroimaging evaluation was performed in order to assess clinical and behavioural features of the patient. From a neuropsychological point of view, the patient showed a typical cognitive profile of subjects affected by NfPPA: a prominent language deficit, associated with impairments in several cognitive domains after three years from the onset of the symptomatology. The most intriguing feature is that SPECT revealed hypoperfusion in the right frontal cortex, albeit the patient is right-handed. This unexpected finding shows that NfPPA may arise not only from cortical abnormalities in the language-dominant left hemisphere, but also from right hemisphere involvement in a right hander (crossed aphasia).

  15. Hemispherical anisotropic patterns of the Earth's inner core.

    PubMed

    Mattesini, Maurizio; Belonoshko, Anatoly B; Buforn, Elisa; Ramírez, María; Simak, Sergei I; Udías, Agustín; Mao, Ho-Kwang; Ahuja, Rajeev

    2010-05-25

    It has been shown that the Earth's inner core has an axisymmetric anisotropic structure with seismic waves traveling approximately 3% faster along polar paths than along equatorial directions. Hemispherical anisotropic patterns of the solid Earth's core are rather complex, and the commonly used hexagonal-close-packed iron phase might be insufficient to account for seismological observations. We show that the data we collected are in good agreement with the presence of two anisotropically specular east and west core hemispheres. The detected travel-time anomalies can only be disclosed by a lattice-preferred orientation of a body-centered-cubic iron aggregate, having a fraction of their [111] crystal axes parallel to the Earth's rotation axis. This is compelling evidence for the presence of a body-centered-cubic Fe phase at the top of the Earth's inner core.

  16. Hunting the Coolest Substellar Dwarfs in the Northern Hemisphere

    NASA Astrophysics Data System (ADS)

    Zuckerman, Ben; Rodriguez, David; Melis, Carl; Song, Inseok

    2011-02-01

    The few lowest mass substellar objects discovered in previous imaging surveys are found to have large semi-major axes, typically hundreds of AU. We show that at such large separations and toward old stars one has the best chance to detect the coolest dwarfs, with effective temperatures of <=500 K (the so-called ``Y dwarfs''). Effective temperatures of 500 K represent a region of temperature space that has yet to be probed. As such, the discovery of such cool objects will illuminate their physics and chemistry and will provide observational data to test planetary models. To discover one or more Y dwarfs, we are proposing to continue our survey with FLAMINGOS of northern hemisphere white dwarfs with ages >2 Gyr that lie within 25 pc of Earth. These observations will complement our southern hemisphere survey with ISPI and NEWFIRM at CTIO.

  17. Film Boiling on Downward Quenching Hemisphere of Varying Sizes

    SciTech Connect

    Chan S. Kim; Kune Y. Suh; Joy L. Rempe; Fan-Bill Cheung; Sang B. Kim

    2004-04-01

    Film boiling heat transfer coefficients for a downward-facing hemispherical surface are measured from the quenching tests in DELTA (Downward-boiling Experimental Laminar Transition Apparatus). Two test sections are made of copper to maintain low Biot numbers. The outer diameters of the hemispheres are 120 mm and 294 mm, respectively. The thickness of all the test sections is 30 mm. The effect of diameter on film boiling heat transfer is quantified utilizing results obtained from the test sections. The measured data are compared with the numerical predictions from laminar film boiling analysis. The measured heat transfer coefficients are found to be greater than those predicted by the conventional laminar flow theory on account of the interfacial wavy motion incurred by the Helmholtz instability. Incorporation of the wavy motion model considerably improves the agreement between the experimental and numerical results in terms of heat transfer coefficient. In addition, the interfacial wavy motion and the quenching process are visualized through a digital camera.

  18. Left hemispheric advantage for numerical abilities in the bottlenose dolphin.

    PubMed

    Kilian, Annette; von Fersen, Lorenzo; Güntürkün, Onur

    2005-02-28

    In a two-choice discrimination paradigm, a bottlenose dolphin discriminated relational dimensions between visual numerosity stimuli under monocular viewing conditions. After prior binocular acquisition of the task, two monocular test series with different number stimuli were conducted. In accordance with recent studies on visual lateralization in the bottlenose dolphin, our results revealed an overall advantage of the right visual field. Due to the complete decussation of the optic nerve fibers, this suggests a specialization of the left hemisphere for analysing relational features between stimuli as required in tests for numerical abilities. These processes are typically right hemisphere-based in other mammals (including humans) and birds. The present data provide further evidence for a general right visual field advantage in bottlenose dolphins for visual information processing. It is thus assumed that dolphins possess a unique functional architecture of their cerebral asymmetries.

  19. FOXP2 variation modulates functional hemispheric asymmetries for speech perception.

    PubMed

    Ocklenburg, Sebastian; Arning, Larissa; Gerding, Wanda M; Epplen, Jörg T; Güntürkün, Onur; Beste, Christian

    2013-09-01

    Left-hemispheric language dominance is a well-known characteristic of the human language system, but the molecular mechanisms underlying this crucial feature of vocal communication are still far from being understood. The forkhead box P2 gene FOXP2, which has been related to speech development, constitutes an interesting candidate gene in this regard. Therefore, the present study was aimed at investigating effects of variation in FOXP2 on individual language dominance. To this end, we used a dichotic listening and a visual half-field task in a sample of 456 healthy adults. The FOXP2 SNPs rs2396753 and rs12533005 were found to be significantly associated with the distribution of correct answers on the dichotic listening task. These results show that variation in FOXP2 may contribute to the inter-individual variability in hemispheric asymmetries for speech perception.

  20. Do temporal processes underlie left hemisphere dominance in speech perception?

    PubMed Central

    Scott, Sophie K; McGettigan, Carolyn

    2014-01-01

    It is not unusual to find it stated as a fact that the left hemisphere is specialized for the processing of rapid, or temporal aspects of sound, and that the dominance of the left hemisphere in the perception of speech can be a consequence of this specialisation. In this review we explore the history of this claim and assess the weight of this assumption. We will demonstrate that instead of a supposed sensitivity of the left temporal lobe for the acoustic properties of speech, it is the right temporal lobe which shows a marked preference for certain properties of sounds, for example longer durations, or variations in pitch. We finish by outlining some alternative factors that contribute to the left lateralization of speech perception. PMID:24125574

  1. Hemispherical wineglass resonators fabricated from the microcrystalline diamond

    NASA Astrophysics Data System (ADS)

    Heidari, Amir; Chan, Mei-Lin; Yang, Hsueh-An; Jaramillo, Gerardo; Taheri-Tehrani, Parsa; Fonda, Peter; Najar, Hadi; Yamazaki, Kazuo; Lin, Liwei; Horsley, David A.

    2013-12-01

    We present the development of millimeter scale 3D hemispherical shell resonators fabricated from the polycrystalline diamond, a material with low thermoelastic damping and very high stiffness. These hemispherical wineglass resonators with 1.1 mm diameter are fabricated through a combination of micro-electro discharge machining (EDM) and silicon micromachining techniques. Using piezoelectric and electrostatic excitation and optical vibration measurement, the elliptical wineglass vibration mode is determined to be at 18.321 kHz, with the two degenerate wineglass modes having a relative frequency mismatch of 0.03%. A study on the effect of the size and misalignment of the anchor and resonator's radius variation on both the average frequency and frequency mismatch of the 2θ elliptical vibration modes is carried out. It is shown that the absolute frequency of a wineglass resonator will increase with the anchor size. It is also demonstrated that the fourth harmonic of radius variation is linearly related to the frequency mismatch.

  2. Preschoolers' mental rotation of letters: Sex differences in hemispheric asymmetry.

    PubMed

    Hahn, Nicola; Jansen, Petra; Heil, Martin

    2010-12-01

    Adults' mental rotation performance has been found to produce one of the largest sex differences in cognition accompanied by sex differences in functional cerebral asymmetry. In this study sex differences in mental rotation of letters were investigated with children as young as five years. Based on the electrophysiological brain correlates of mental rotation, we observed a bilateral brain activity for preschool girls whereas the preschool boys' brain activity was clearly lateralized towards the right hemisphere if and only if mental rotation was needed to solve the task. At the same time, we did not find any sex differences in mental rotation speed or accuracy. Thus, sex differences in functional hemispheric asymmetry during mental rotation do not require hormonal changes that occur during puberty.

  3. First Geological Mapping Investigation of the Occator Hemisphere of Ceres (180°-360°E), from NASA’s Dawn Mission

    NASA Astrophysics Data System (ADS)

    Buczkowski, Debra; Williams, David; Mest, Scott; Scully, Jennifer E. C.; Jaumann, Ralf; Russell, Chris T.; Raymond, Carol; Roatsch, Thomas; Preusker, Frank; Park, Ryan; Nathues, Andreas; Hoffmann, Martin; Schäfer, Michael; Platz, Thomas; Schenk, Paul M.; Marchi, Simone; O'Brien, David P.; De Sanctis, M. Cristina

    2015-11-01

    The Dawn Science team divided the surface of Ceres into quadrangles, in order to facilitate systematic geological mapping, which is a tool used to methodically observe and interpret the surfaces of planetary bodies. Here we present a geological map from 180° - 360°E longitude of Ceres, which we assemble from a combination of quadrangle-scale geological maps. Geologic units are characterized based on physical attributes such as albedo, morphology, structure, color, and topography, and are related to geologic processes such as volcanism, tectonism, impact cratering, deposition, and weathering. This hemisphere is dominated by a heavily cratered terrain, with both fresh-looking and putatively-relaxed craters evident. Also evident is Occator crater and the feature known as Spot 5, the brightest of the “bright spots” on Ceres. Linear structures are prevalent, but whether they are formed due to impact stresses or by internal activity has not yet been determined. However, the numerous polygonal craters suggest significant sub-surface fracturing. Color data indicates considerable compositional diversity, specifically around Spot 5, as well as around some of the other craters and associated with some of the linear structures. Variations in crater abundance in different parts of this hemisphere suggest that some type of resurfacing might have occurred. Domical, positive relief features are present in some of the craters; a 5 km high feature informally known as “the pyramid” is also identified. Determining the processes by which these topographically high features formed is of major interest in this mapping effort. Ongoing work will include the development of a detailed geological history and the use of crater morphologies to infer the composition and physical properties of the sub-surface. Currently, our geological mapping is based on Approach (~1.3 km/p) and Survey (~400 m/p) mosaics of clear and color filter data from the Dawn spacecraft’s Framing Camera. In

  4. Hemispheric Symmetries of Plio-Pleistocene Surface Ocean Conditions: Insights from Southern Hemisphere ODP Sites 1125 and 1088

    NASA Astrophysics Data System (ADS)

    Lawrence, K. T.; Peterson, L.; Kelly, C.; Miller, H.; Seidenstein, J.

    2013-12-01

    For decades, most studies of Plio-Pleistocene climate and of the transition from the warmth of the Pliocene to the colder and more variable conditions of the Pleistocene have focused solely on northern hemisphere climate processes and responses. Here, we explore the southern hemisphere response to this major climate transition by documenting ocean surface conditions at Ocean Drilling Program Sites 1125 (42οS, 178οW, 1360m) and 1088 (40οS, 15οE, 2082m) through the Plio-Pleistocene. Secular trends in alkenone-derived sea surface temperature (SST) records indicate that these mid-latitude southern hemisphere sites cooled ~3-4οC over the past 3 Myrs, a magnitude comparable to sites located at similar latitudes in both the North Atlantic and North Pacific. This observation suggests that contraction of the low latitude warm pool was hemispherically symmetric. Our highly resolved (3 kyr resolution) Site 1125 SST record bears considerable structural similarity to SST records from nearby site 1123 (42οS,171οW) as well as sites 846 (3οS, 91οW) in the eastern equatorial Pacific and U1313 (41οN, 33οW) in the North Atlantic. Most of these SST records are dominated by 100k power and contain strong secondary 41k peaks throughout the past 3 million years. North Atlantic site U1313 is the exception, mirroring the shift in dominant periodicity from 41k to 100k associated with the mid-Pleistocene transition, that has long been observed in benthic oxygen isotope records. Finally, in southern hemisphere SST records as well as at site U1313 from the north Atlantic we observe weak precessional power that is not evident in benthic oxygen isotope record. These results suggest a fairly hemispherically-coordinated response of ocean surface temperature to changing global climate conditions during the Plio-Pleistocene in terms of both secular trends and dominant orbital frequencies.

  5. Post-Stroke Longitudinal Alterations of Inter-Hemispheric Correlation and Hemispheric Dominance in Mouse Pre-Motor Cortex

    PubMed Central

    Panarese, Alessandro; Alia, Claudia; Micera, Silvestro; Caleo, Matteo; Di Garbo, Angelo

    2016-01-01

    Purpose Limited restoration of function is known to occur spontaneously after an ischemic injury to the primary motor cortex. Evidence suggests that Pre-Motor Areas (PMAs) may “take over” control of the disrupted functions. However, little is known about functional reorganizations in PMAs. Forelimb movements in mice can be driven by two cortical regions, Caudal and Rostral Forelimb Areas (CFA and RFA), generally accepted as primary motor and pre-motor cortex, respectively. Here, we examined longitudinal changes in functional coupling between the two RFAs following unilateral photothrombotic stroke in CFA (mm from Bregma: +0.5 anterior, +1.25 lateral). Methods Local field potentials (LFPs) were recorded from the RFAs of both hemispheres in freely moving injured and naïve mice. Neural signals were acquired at 9, 16 and 23 days after surgery (sub-acute period in stroke animals) through one bipolar electrode per hemisphere placed in the center of RFA, with a ground screw over the occipital bone. LFPs were pre-processed through an efficient method of artifact removal and analysed through: spectral,cross-correlation, mutual information and Granger causality analysis. Results Spectral analysis demonstrated an early decrease (day 9) in the alpha band power in both the RFAs. In the late sub-acute period (days 16 and 23), inter-hemispheric functional coupling was reduced in ischemic animals, as shown by a decrease in the cross-correlation and mutual information measures. Within the gamma and delta bands, correlation measures were already reduced at day 9. Granger analysis, used as a measure of the symmetry of the inter-hemispheric causal connectivity, showed a less balanced activity in the two RFAs after stroke, with more frequent oscillations of hemispheric dominance. Conclusions These results indicate robust electrophysiological changes in PMAs after stroke. Specifically, we found alterations in transcallosal connectivity, with reduced inter-hemispheric functional

  6. Shifting Attentional Priorities: Control of Spatial Attention through Hemispheric Competition

    PubMed Central

    Szczepanski, Sara M.; Kastner, Sabine

    2013-01-01

    Regions of frontal and posterior parietal cortex are known to control the allocation of spatial attention across the visual field. However, the neural mechanisms underlying attentional control in the intact human brain remain unclear, with some studies supporting a hemispatial theory emphasizing a dominant function of the right hemisphere and others supporting an interhemispheric competition theory. We previously found neural evidence to support the latter account, in which topographically organized frontoparietal areas each generate a spatial bias, or “attentional weight,” toward the contralateral hemifield, with the sum of the weights constituting the overall bias that can be exerted across visual space. Here, we used a multimodal approach consisting of functional magnetic resonance imaging (fMRI) of spatial attention signals, behavioral measures of spatial bias, and fMRI-guided single-pulse transcranial magnetic stimulation (TMS) to causally test this interhemispheric competition account. Across the group of fMRI subjects, we found substantial individual differences in the strengths of the frontoparietal attentional weights in each hemisphere, which predicted subjects’ respective behavioral preferences when allocating spatial attention, as measured by a landmark task. Using TMS to interfere with attentional processing within specific topographic frontoparietal areas, we then demonstrated that the attentional weights of individual subjects, and thus their spatial attention behavior, could be predictably shifted toward one visual field or the other, depending on the site of interference. The results of our multimodal approach, combined with an emphasis on neural and behavioral individual differences, provide compelling evidence that spatial attention is controlled through competitive interactions between hemispheres rather than a dominant right hemisphere in the intact human brain. PMID:23516306

  7. Predicting North American Scolytinae invasions in the Southern Hemisphere.

    PubMed

    Lantschner, Maria Victoria; Atkinson, Thomas H; Corley, Juan C; Liebhold, Andrew M

    2017-01-01

    Scolytinae species are recognized as one of the most important tree mortality agents in coniferous forests worldwide, and many are known invaders because they are easily transported in wood products. Nonnative trees planted in novel habitats often exhibit exceptional growth, in part because they escape herbivore (such as Scolytinae) pressure from their native range. Increasing accidental introductions of forest pest species as a consequence of international trade, however, is expected to diminish enemy release of nonnative forest trees. In this context, there is need to characterize patterns of forest herbivore species invasion risks at global scales. In this study, we analyze the establishment potential of 64 North American Scolytinae species in the Southern Hemisphere. We use climate-based ecological niche models (MaxEnt) to spatially define the potential distribution of these Scolytinae species in regions of the Southern Hemisphere were pines are planted. Our model predicts that all of the pine-growing regions of the Southern Hemisphere are capable of supporting some species of North American Scolytinae, but there are certain "hotspot" regions, southeastern Argentina, Bolivia, Chile, Peru and southwestern Australia, that appear to be suitable for a particularly large number of species. The species with the highest predicted risk of establishment were Dendroctonus valens, Xyleborus intrusus, Hylastes tenuis, Ips grandicollis, Gnathotrichus sulcatus, and Ips calligraphus. Given that global commerce is anticipated to continue to increase, we can expect that more Scolytinae species will continue to establish outside their range. Our results provide information useful for identifying a global list of potential invasive species in pine plantations, and may assist in the design of comprehensive strategies aimed at reducing pest establishment in Southern Hemisphere forest plantations.

  8. The effects of orography on midlatitude Northern Hemisphere dry climates

    SciTech Connect

    Broccoli, A.J.; Manabe, S. )

    1992-11-01

    The role of mountains in maintaining extensive midlatitude arid regions in the Northern Hemisphere was studied utilizing simulations from the GFDL GMC with and without orography. In the integration with mountains, dry climates were simulated over the interior of North America and central Asia, in good agreement with the observed climate. The results from these experiments indicate that midlatitude dryness is due largely to the existence of orography. 38 refs.

  9. Hemispheric Asymmetries in Meaning Selection: Evidence from the Disambiguation of Homophonic vs. Heterophonic Homographs

    ERIC Educational Resources Information Center

    Peleg, Orna; Markus, Andrey; Eviatar, Zohar

    2012-01-01

    Research investigating hemispheric asymmetries in meaning selection using homophonic homographs (e.g., "bank"), suggests that the left hemisphere (LH) quickly selects contextually relevant meanings, whereas the right hemisphere (RH) maintains a broader spectrum of meanings including those that are contextually irrelevant (e.g., Faust & Chiarello,…

  10. Knowledge-Based Inferences across the Hemispheres: Domain Makes a Difference

    ERIC Educational Resources Information Center

    Shears, Connie; Hawkins, Amanda; Varner, Andria; Lewis, Lindsey; Heatley, Jennifer; Twachtmann, Lisa

    2008-01-01

    Language comprehension occurs when the left-hemisphere (LH) and the right-hemisphere (RH) share information derived from discourse [Beeman, M. J., Bowden, E. M., & Gernsbacher, M. A. (2000). Right and left hemisphere cooperation for drawing predictive and coherence inferences during normal story comprehension. "Brain and Language, 71", 310-336].…

  11. The Representation of Discourse in the Two Hemispheres: An Individual Differences Investigation

    ERIC Educational Resources Information Center

    Prat, Chantel S.; Long, Debra L.; Baynes, Kathleen

    2007-01-01

    Two experiments were conducted to investigate discourse representation in the two cerebral hemispheres as a function of reading skill. We used a lateralized visual-field procedure to compare left hemisphere (LH) and right hemisphere (RH) sensitivity to different discourse relations in readers with varying skill levels. In Experiment 1, we…

  12. When Side Matters: Hemispheric Processing and the Visual Specificity of Emotional Memories

    ERIC Educational Resources Information Center

    Kensinger, Elizabeth A.; Choi, Elizabeth S.

    2009-01-01

    Previous studies have shown that the right hemisphere processes the visual details of objects and the emotionality of information. These two roles of the right hemisphere have not been examined concurrently. In the present study, the authors examined whether right hemisphere processing would lead to particularly good memory for the visual details…

  13. Hemispheric Division of Function Is the Result of Independent Probabilistic Biases

    ERIC Educational Resources Information Center

    Whitehouse, Andrew J. O.; Bishop, Dorothy V. M.

    2009-01-01

    Verbal and visuospatial abilities are typically subserved by different cerebral hemispheres: the left hemisphere for the former and the right hemisphere for the latter. However little is known of the origin of this division of function. Causal theories propose that functional asymmetry is an obligatory pattern of organisation, while statistical…

  14. Association between Therapy Outcome and Right-Hemispheric Activation in Chronic Aphasia

    ERIC Educational Resources Information Center

    Richter, Maria; Miltner, Wolfgang H. R.; Straube, Thomas

    2008-01-01

    The role of the right hemisphere for language processing and successful therapeutic interventions in aphasic patients is a matter of debate. This study explored brain activation in right-hemispheric areas and left-hemispheric perilesional areas in response to language tasks in chronic non-fluent aphasic patients before and after constraint-induced…

  15. Hemisphere Lateralization Is Influenced by Bilingual Status and Composition of Words

    ERIC Educational Resources Information Center

    Peng, Gang; Wang, William S.-Y.

    2011-01-01

    It has been generally accepted that the left hemisphere is more functionally specialized for language than the right hemisphere for right-handed monolinguals. But more and more studies have also demonstrated right hemisphere advantage for some language tasks with certain participants. A recent comprehensive survey has shown that hemisphere…

  16. Hemispheric Specialization for Emotional Word Processing Is a Function of SSRI Responsiveness

    ERIC Educational Resources Information Center

    Walsh, Amy; McDowall, John; Grimshaw, Gina M.

    2010-01-01

    Vulnerability to depression and non-response to Selective Serotonin Reuptake Inhibitors (SSRIs) are associated with specific neurophysiological characteristics including greater right hemisphere (RH) relative to left hemisphere (LH) activity. The present study investigated the relationship between hemispheric specialization and processing of…

  17. A Response to Gazzaniga: Language in the Right Hemisphere, Convergent Perspectives.

    ERIC Educational Resources Information Center

    Zaidel, Eran

    1983-01-01

    Gazzaniga argues that without language right hemisphere cognition is vastly limited and that most normal right hemispheres have no language and only "rudimentary cognition." These assertion ignore important nonlinguistic observations, as well as findings with hemispheric sodium amytal anesthesia and laterality effects for complex cognitive tasks…

  18. Sex and hemispheric differences in facial invariants extraction.

    PubMed

    Godard, Ornella; Fiori, Nicole

    2012-01-01

    This present study investigates sex differences in hemispheric cooperation during a facial identity matching task. The method used was a divided visual field paradigm in which the probe face was neutral or expressive and the target face was always neutral. Probe and target faces were presented both unilaterally and sequentially. A total of 28 right-handed women and 32 right-handed men participated in this study. The results confirm the women's advantage in face recognition and reveal symmetrical interhemispheric cooperation in women only. In men, processing time was faster when the probe face appeared in the left visual field-and encoded by the right hemisphere-and the target in the right visual field-projected to the left hemisphere-compared to the reverse direction. Interestingly, the data also show that women were not influenced by the expression of the probe face when matching identity, whereas men were always faster when the probe face was neutral, like the target, than when it was expressive. These results are discussed in light of Bruce and Young's (1986) model, and in terms of view-dependent and view-independent processes.

  19. Right-hemispheric dominance for visual remapping in humans.

    PubMed

    Pisella, L; Alahyane, N; Blangero, A; Thery, F; Blanc, S; Pelisson, D

    2011-02-27

    We review evidence showing a right-hemispheric dominance for visuo-spatial processing and representation in humans. Accordingly, visual disorganization symptoms (intuitively related to remapping impairments) are observed in both neglect and constructional apraxia. More specifically, we review findings from the intervening saccade paradigm in humans--and present additional original data--which suggest a specific role of the asymmetrical network at the temporo-parietal junction (TPJ) in the right hemisphere in visual remapping: following damage to the right dorsal posterior parietal cortex (PPC) as well as part of the corpus callosum connecting the PPC to the frontal lobes, patient OK in a double-step saccadic task exhibited an impairment when the second saccade had to be directed rightward. This singular and lateralized deficit cannot result solely from the patient's cortical lesion and, therefore, we propose that it is due to his callosal lesion that may specifically interrupt the interhemispheric transfer of information necessary to execute accurate rightward saccades towards a remapped target location. This suggests a specialized right-hemispheric network for visuo-spatial remapping that subsequently transfers target location information to downstream planning regions, which are symmetrically organized.

  20. Controlled semantic processes within and between the two cerebral hemispheres.

    PubMed

    Peleg, Orna; Eviatar, Zohar

    2017-01-01

    To test the separate and combined abilities of the two cerebral hemispheres to perform controlled semantic selection and integration processes, Hebrew readers saw pairs of words and had to decide whether the two words were semantically related. The first word in each pair was presented centrally. The second word was presented in the left, right, or central visual field (LVF, RVF, and CVF). We compared response latencies for related pairs in two conditions: In the ambiguous condition, the first word was a homograph (either homophonic or heterophonic) and the second word was related to either its dominant or subordinate meaning. In the unambiguous condition, homographs were replaced with unambiguous control words. Irrespective of VF or homograph type, response times for ambiguous pairs were significantly longer than for unambiguous pairs only when targets were related to the subordinate meaning of the homograph. In the left hemisphere (RVF/LH), this ambiguity effect was larger for heterophones than for homophones, whereas in the right hemisphere (LVF/RH), similar patterns were observed for both types of homographs. Finally, performance patterns in the CVF revealed the same patterns as those in the RVF/LH, and were different from those in the LVF/RH. The implications of these results are discussed.

  1. Hemispheric asymmetry and somatotopy of afferent inhibition in healthy humans.

    PubMed

    Helmich, R C G; Bäumer, T; Siebner, H R; Bloem, B R; Münchau, A

    2005-11-01

    A conditioning electrical stimulus to a digital nerve can inhibit the motor-evoked potentials (MEPs) in adjacent hand muscles elicited by transcranial magnetic stimulation (TMS) to the contralateral primary motor cortex (M1) when given 25-50 ms before the TMS pulse. This is referred to as short-latency afferent inhibition (SAI). We studied inter-hemispheric differences (Experiment 1) and within-limb somatotopy (Experiment 2) of SAI in healthy right-handers. In Experiment 1, conditioning electrical pulses were applied to the right or left index finger (D2) and MEPs were recorded from relaxed first dorsal interosseus (FDI) and abductor digiti minimi (ADM) muscles ipsilateral to the conditioning stimulus. We found that SAI was more pronounced in right hand muscles. In Experiment 2, electrical stimulation was applied to the right D2 and MEPs were recorded from ipsilateral FDI, extensor digitorum communis (EDC) and biceps brachii (BB) muscles. The amount of SAI did not differ between FDI, EDC and BB muscles. These data demonstrate inter-hemispheric differences in the processing of cutaneous input from the hand, with stronger SAI in the dominant left hemisphere. We also found that SAI occurred not only in hand muscles adjacent to electrical digital stimulation, but also in distant hand and forearm and also proximal arm muscles. This suggests that SAI induced by electrical D2 stimulation is not focal and somatotopically specific, but a more widespread inhibitory phenomenon.

  2. Merging two data sets of hemispheric Sunspot Numbers

    NASA Astrophysics Data System (ADS)

    Rybák, J.; Bendík, P.; Temmer, M.; Veronig, A.; Hanslmeier, A.

    First results on merging two data sets of hemispheric sunspot numbers -- from the Kanzelhöhe Solar Observatory and the Skalnaté Pleso Observatory -- for the time span 1977 -- 1978 are presented. A total coverage of 86% was reached for the merged data set. In order to have a homogeneous time series, the daily sunspot numbers for the full disk from both observing stations were normalized to the international relative sunspot number of the day. The derived hemispheric sunspot numbers from Kanzelhöhe and Skalnaté Pleso Observatory %compared for 290 common observing show very high correlations (r ≳ 0.95), and the estimated data noise yields significant differences only for small values of sunspot numbers. These outcomes demonstrate the high potential of the applied merging procedure, and are the basis for an ongoing project to derive hemispheric sunspot numbers back to the year 1945 using sunspot drawings from Kanzelhöhe and Skalnaté Pleso Observatory.

  3. Learning-related brain hemispheric dominance in sleeping songbirds.

    PubMed

    Moorman, Sanne; Gobes, Sharon M H; van de Kamp, Ferdinand C; Zandbergen, Matthijs A; Bolhuis, Johan J

    2015-03-12

    There are striking behavioural and neural parallels between the acquisition of speech in humans and song learning in songbirds. In humans, language-related brain activation is mostly lateralised to the left hemisphere. During language acquisition in humans, brain hemispheric lateralisation develops as language proficiency increases. Sleep is important for the formation of long-term memory, in humans as well as in other animals, including songbirds. Here, we measured neuronal activation (as the expression pattern of the immediate early gene ZENK) during sleep in juvenile zebra finch males that were still learning their songs from a tutor. We found that during sleep, there was learning-dependent lateralisation of spontaneous neuronal activation in the caudomedial nidopallium (NCM), a secondary auditory brain region that is involved in tutor song memory, while there was right hemisphere dominance of neuronal activation in HVC (used as a proper name), a premotor nucleus that is involved in song production and sensorimotor learning. Specifically, in the NCM, birds that imitated their tutors well were left dominant, while poor imitators were right dominant, similar to language-proficiency related lateralisation in humans. Given the avian-human parallels, lateralised neural activation during sleep may also be important for speech and language acquisition in human infants.

  4. Role of brain hemispheric dominance in anticipatory postural control strategies.

    PubMed

    Cioncoloni, David; Rosignoli, Deborah; Feurra, Matteo; Rossi, Simone; Bonifazi, Marco; Rossi, Alessandro; Mazzocchio, Riccardo

    2016-07-01

    Most of the cerebral functions are asymmetrically represented in the two hemispheres. Moreover, dexterity and coordination of the distal segment of the dominant limbs depend on cortico-motor lateralization. In this study, we investigated whether postural control may be also considered a lateralized hemispheric brain function. To this aim, 15 young subjects were tested in standing position by measuring center of pressure (COP) shifts along the anteroposterior axis (COP-Y) during dynamic posturography before and after continuous Theta Burst Stimulation (cTBS) intervention applied to the dominant or non-dominant M1 hand area as well as to the vertex. We show that when subjects were expecting a forward platform translation, the COP-Y was positioned significantly backward or forward after dominant or non-dominant M1 stimulation, respectively. We postulate that cTBS applied on M1 may have disrupted the functional connectivity between intra- and interhemispheric areas implicated in the anticipatory control of postural stability. This study suggests a functional asymmetry between the two homologous primary motor areas, with the dominant hemisphere playing a critical role in the selection of the appropriate postural control strategy.

  5. Are Karakoram temperatures out of phase compared to hemispheric trends?

    NASA Astrophysics Data System (ADS)

    Asad, Fayaz; Zhu, Haifeng; Zhang, Hui; Liang, Eryuan; Muhammad, Sher; Farhan, Suhaib Bin; Hussain, Iqtidar; Wazir, Muhammad Atif; Ahmed, Moinuddin; Esper, Jan

    2016-07-01

    In contrast to a global retreating trend, glaciers in the Karakoram showed stability and/or mass gaining during the past decades. This "Karakoram Anomaly" has been assumed to result from an out-of-phase temperature trend compared to hemispheric scales. However, the short instrumental observations from the Karakoram valley bottoms do not support a quantitative assessment of long-term temperature trends in this high mountain area. Here, we presented a new April-July temperature reconstruction from the Karakoram region in northern Pakistan based on a high elevation (~3600 m a.s.l.) tree-ring chronology covering the past 438 years (AD 1575-2012). The reconstruction passes all statistical calibration and validation tests and represents 49 % of the temperature variance recorded over the 1955-2012 instrumental period. It shows a substantial warming accounting to about 1.12 °C since the mid-twentieth century, and 1.94 °C since the mid-nineteenth century, and agrees well with the Northern Hemisphere temperature reconstructions. These findings provide evidence that the Karakoram temperatures are in-phase, rather than out-of-phase, compared to hemispheric scales since the AD 1575. The synchronous temperature trends imply that the anomalous glacier behavior reported from the Karakoram may need further explanations beyond basic regional thermal anomaly.

  6. Obliquity Control On Southern Hemisphere Climate During The Last Glacial

    PubMed Central

    Fogwill, C.J.; Turney, C.S.M.; Hutchinson, D.K.; Taschetto, A.S.; England, M.H.

    2015-01-01

    Recent paleoclimate reconstructions have challenged the traditional view that Northern Hemisphere insolation and associated feedbacks drove synchronous global climate and ice-sheet volume during the last glacial cycle. Here we focus on the response of the Patagonian Ice Sheet, and demonstrate that its maximum expansion culminated at 28,400 ± 500 years before present (28.4 ± 0.5 ka), more than 5,000 years before the minima in 65°N summer insolation and the formally-defined Last Glacial Maximum (LGM) at 21,000 ± 2,000 years before present. To investigate the potential drivers of this early LGM (eLGM), we simulate the effects of orbital changes using a suite of climate models incorporating prescribed and evolving sea-ice anomalies. Our analyses suggest that Antarctic sea-ice expansion at 28.5 ka altered the location and intensity of the Southern Hemisphere storm track, triggering regional cooling over Patagonia of 5°C that extends across the wider mid-southern latitudes. In contrast, at the LGM, continued sea-ice expansion reduced regional temperature and precipitation further, effectively starving the ice sheet and resulting in reduced glacial expansion. Our findings highlight the dominant role that orbital changes can play in driving Southern Hemisphere glacial climate via the sensitivity of mid-latitude regions to changes in Antarctic sea-ice extent. PMID:26115344

  7. The Unusual Southern Hemisphere Stratosphere Winter of 2002

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Nash, Eric R.

    2003-01-01

    The southern hemisphere stratospheric winter of 2002 was the most unusual winter yet observed in the southern hemisphere climate record. Temperatures near the edge of the Antarctic polar vortex were considerably warmer than normal over the entire course of the winter. The polar night jet was considerably weaker than normal, and was displaced more poleward than has been observed in previous winters. These record high temperatures and weak jet resulted from a series of wave events that took place over the course of the winter. The first large event occurred on 15 May, and the final warming occurred on 25 October. The propagation of these wave events from the troposphere is diagnosed from time series of Eliassen-Palm flux vectors. The wave events tended to occur irregularly over the course of the winter, and pre-conditioned the polar night jet for the extremely large wave event of 22 September. This large wave event resulted in the first ever observed major stratospheric warming in the southern hemisphere. This wave event split the Antarctic ozone hole. The combined effect of the wave events of the 2002 winter resulted in the smallest ozone hole observed since 1988.

  8. Theory of mind and pragmatic understanding following right hemisphere damage.

    PubMed

    Siegal, M; Carrington, J; Radel, M

    1996-04-01

    It has been maintained that 3-year-olds' difficulties in correctly predicting the undesired outcome of false beliefs reflects difficulties in interpreting the implications of conversations rather than a conceptual limitation in their theory of mind. As the right hemisphere has been seen to be responsible for the interpretation of the pragmatic aspects of communication, right-hemisphere-damaged (RHD) and left-hemisphere-damaged (LHD) adult patients in our study were compared on their ability to correctly draw inferences in false belief tasks. The RHD but not the LHD patients were found to have difficulties similar to those of young children in understanding the conversational implications test questions. Most reported that a central story character would look for a pet in the place where it was really located instead of where the character believed it was located. However, when then asked in a control question where the pet really was, the RHD patients often switched their answer to the test question and referred to the believed location. Removal of the need to infer the questioner's meaning enabled both RHD and LHD subjects to make correct false belief predictions. The results are discussed in terms of the effects of brain damage on spatial memory and the pragmatic demands of theory of mind tasks.

  9. Changes in meandering of the Northern Hemisphere circulation

    NASA Astrophysics Data System (ADS)

    Di Capua, Giorgia; Coumou, Dim

    2016-09-01

    Strong waves in the mid-latitude circulation have been linked to extreme surface weather and thus changes in waviness could have serious consequences for society. Several theories have been proposed which could alter waviness, including tropical sea surface temperature anomalies or rapid climate change in the Arctic. However, so far it remains unclear whether any changes in waviness have actually occurred. Here we propose a novel meandering index which captures the maximum waviness in geopotential height contours at any given day, using all information of the full spatial position of each contour. Data are analysed on different time scale (from daily to 11 day running means) and both on hemispheric and regional scales. Using quantile regressions, we analyse how seasonal distributions of this index have changed over 1979-2015. The most robust changes are detected for autumn which has seen a pronounced increase in strongly meandering patterns at the hemispheric level as well as over the Eurasian sector. In summer for both the hemisphere and the Eurasian sector, significant downward trends in meandering are detected on daily timescales which is consistent with the recently reported decrease in summer storm track activity. The American sector shows the strongest increase in meandering in the warm season: in particular for 11 day running mean data, indicating enhanced amplitudes of quasi-stationary waves. Our findings have implications for both the occurrence of recent cold spells and persistent heat waves in the mid-latitudes.

  10. Connectivity measures in the Poffenberger paradigm indicate hemispheric asymmetries

    PubMed Central

    Erbil, Nurhan; Yagcioglu, Suha

    2016-01-01

    Summary The Poffenberger paradigm is a well-known measure of interhemispheric transfer delays, calculated on the basis of the crossed vs uncrossed reaction time difference (CUD). However, the proper interpretation of CUD is extensively debated in the literature. In this study we used connectivity measures in an attempt to interpret CUD from the perspective of functional connectivity. Accordingly, we tried to define functional couplings in the Poffenberger paradigm; we used a simple choice version of the paradigm, and included a stimulation only (SO) condition for comparison. As an index of functional coupling we employed partial directed coherence, exploiting bilateral grouping of the electrodes to compute intra- and interhemispheric connection weight ratios (CWRs). Our findings indicated modulations in functional weights in relation to the SO condition, rather than the crossed and uncrossed conditions, such that the response executed by the right hemisphere yielded a decrease in intra-, yet an increase in interhemispheric CWRs, whereas the left hemisphere interactions showed connectivity patterns similar to the SO condition irrespective of the side of movement. Overall, our results suggest modulation of connectivity in the same/similar system, which was found to be optimized, in terms of hemispheric asymmetries, to different tasks. PMID:28072385

  11. Obliquity Control On Southern Hemisphere Climate During The Last Glacial.

    PubMed

    Fogwill, C J; Turney, C S M; Hutchinson, D K; Taschetto, A S; England, M H

    2015-06-26

    Recent paleoclimate reconstructions have challenged the traditional view that Northern Hemisphere insolation and associated feedbacks drove synchronous global climate and ice-sheet volume during the last glacial cycle. Here we focus on the response of the Patagonian Ice Sheet, and demonstrate that its maximum expansion culminated at 28,400 ± 500 years before present (28.4 ± 0.5 ka), more than 5,000 years before the minima in 65 °N summer insolation and the formally-defined Last Glacial Maximum (LGM) at 21,000 ± 2,000 years before present. To investigate the potential drivers of this early LGM (eLGM), we simulate the effects of orbital changes using a suite of climate models incorporating prescribed and evolving sea-ice anomalies. Our analyses suggest that Antarctic sea-ice expansion at 28.5 ka altered the location and intensity of the Southern Hemisphere storm track, triggering regional cooling over Patagonia of 5 °C that extends across the wider mid-southern latitudes. In contrast, at the LGM, continued sea-ice expansion reduced regional temperature and precipitation further, effectively starving the ice sheet and resulting in reduced glacial expansion. Our findings highlight the dominant role that orbital changes can play in driving Southern Hemisphere glacial climate via the sensitivity of mid-latitude regions to changes in Antarctic sea-ice extent.

  12. Learning-related brain hemispheric dominance in sleeping songbirds

    PubMed Central

    Moorman, Sanne; Gobes, Sharon M. H.; van de Kamp, Ferdinand C.; Zandbergen, Matthijs A.; Bolhuis, Johan J.

    2015-01-01

    There are striking behavioural and neural parallels between the acquisition of speech in humans and song learning in songbirds. In humans, language-related brain activation is mostly lateralised to the left hemisphere. During language acquisition in humans, brain hemispheric lateralisation develops as language proficiency increases. Sleep is important for the formation of long-term memory, in humans as well as in other animals, including songbirds. Here, we measured neuronal activation (as the expression pattern of the immediate early gene ZENK) during sleep in juvenile zebra finch males that were still learning their songs from a tutor. We found that during sleep, there was learning-dependent lateralisation of spontaneous neuronal activation in the caudomedial nidopallium (NCM), a secondary auditory brain region that is involved in tutor song memory, while there was right hemisphere dominance of neuronal activation in HVC (used as a proper name), a premotor nucleus that is involved in song production and sensorimotor learning. Specifically, in the NCM, birds that imitated their tutors well were left dominant, while poor imitators were right dominant, similar to language-proficiency related lateralisation in humans. Given the avian-human parallels, lateralised neural activation during sleep may also be important for speech and language acquisition in human infants. PMID:25761654

  13. A framework for longitudinal data analysis via shape regression

    NASA Astrophysics Data System (ADS)

    Fishbaugh, James; Durrleman, Stanley; Piven, Joseph; Gerig, Guido

    2012-02-01

    Traditional longitudinal analysis begins by extracting desired clinical measurements, such as volume or head circumference, from discrete imaging data. Typically, the continuous evolution of a scalar measurement is estimated by choosing a 1D regression model, such as kernel regression or fitting a polynomial of fixed degree. This type of analysis not only leads to separate models for each measurement, but there is no clear anatomical or biological interpretation to aid in the selection of the appropriate paradigm. In this paper, we propose a consistent framework for the analysis of longitudinal data by estimating the continuous evolution of shape over time as twice differentiable flows of deformations. In contrast to 1D regression models, one model is chosen to realistically capture the growth of anatomical structures. From the continuous evolution of shape, we can simply extract any clinical measurements of interest. We demonstrate on real anatomical surfaces that volume extracted from a continuous shape evolution is consistent with a 1D regression performed on the discrete measurements. We further show how the visualization of shape progression can aid in the search for significant measurements. Finally, we present an example on a shape complex of the brain (left hemisphere, right hemisphere, cerebellum) that demonstrates a potential clinical application for our framework.

  14. Use of a hyperelastic constitutive law for dry woven forming simulations

    SciTech Connect

    Vidal-Salle, Emmanuelle; Boisse, Philippe; Aimene, Yamina

    2011-05-04

    The increasing use of composite materials in industry implies an increasing use of automatic processes between which LCM processes take a large place. The improvement of such processes needs an extensive use of numerical simulations for all the stages of the process. In particular, it is necessary to know how the dry reinforcement is shaped. This paper presents a hyperelastic constitutive model for textile composite reinforcement at large strain based on an additive potential representative to tension and in-plane shearing. The proposed potential is a function of the right Cauchy Green and structural tensor invariants whose choice corresponds to textile composite reinforcement mechanical behaviour. The model is implemented in a user subroutine of ABAQUS/Explicit. The accuracy of the model has been checked and some simulations are performed on deep drawing with hemispheric punch. A good agreement is obtained with experimental forming experiments.

  15. Hemispheric asymmetries in the transition from action preparation to execution.

    PubMed

    Sulpizio, Valentina; Lucci, Giuliana; Berchicci, Marika; Galati, Gaspare; Pitzalis, Sabrina; Di Russo, Francesco

    2017-03-01

    Flexible and adaptive behavior requires the ability to contextually stop inappropriate actions and select the right one as quickly as possible. Recently, it has been proposed that three brain regions, i.e., the inferior frontal gyrus (iFg), the anterior insula (aIns), and the anterior intraparietal sulcus (aIPs), play an important role in several processing phases of perceptual decision tasks, especially in the preparation, perception and action phases, respectively. However, little is known about hemispheric differences in the activation of these three areas during the transition from perception to action. Many studies have examined how people prepare to stop upcoming responses through both proactive and reactive inhibitory control. Although inhibitory control has been associated with activity in the right prefrontal cortex (PFC), we have previously reported that, during a discriminative response task performed with the right hand, we observed: 1) a bilateral activity in the iFg during the preparation phase, and 2) a left dominant activity in the aIns and aIPs during the transition from perception to action, i.e., the so-called stimulus-response mapping. To clarify the hemispheric dominance of these processes, we combined the high temporal resolution of event-related potentials (ERPs) with the high spatial resolution of event-related functional magnetic resonance imaging (fMRI) while participants performed a discriminative response task (DRT) and a simple response task (SRT) using their non-dominant left hand. We confirmed that proactive inhibitory control originates in the iFg: its activity started one second before the stimulus onset and was released concomitantly to the stimulus appearance. Most importantly, we confirmed the presence of a bilateral iFg activity that seems to reflect a bilateral proactive control rather than a right-hemisphere dominance or a stronger control of the hemisphere contralateral to the responding hand. Further, we observed a stronger

  16. Linking hemispheric radiation budgets, ITCZ shifts, and monsoons

    NASA Astrophysics Data System (ADS)

    McGee, D.; Donohoe, A.; Marshall, J.; Ferreira, D.

    2014-12-01

    We explore the relationship between the Intertropical Convergence Zone (ITCZ), hemispheric heat budgets, and monsoon strength in past climates. Modern seasonal and interannual variability in the globally-averaged position of the ITCZ (as estimated by the tropical precipitation centroid) reflects the interhemispheric heat balance, with the ITCZ's displacement toward the warmer hemisphere directly proportional to atmospheric heat transport into the cooler hemisphere. Model simulations suggest that ITCZ shifts are likely to have obeyed the same relationship with interhemispheric heat transport in response to past changes in orbital parameters, ice sheets, and ocean circulation. This relationship implies that even small (±1 degree) shifts in the mean (annually and zonally averaged) ITCZ require large changes in hemispheric heat budgets, placing tight bounds on mean ITCZ shifts in past climates. To test this energetic argument, we use the observed relationship between mean ITCZ position and tropical sea surface temperature (SST) gradients in combination with proxy-based estimates of past SST gradients to show that mean ITCZ shifts for the mid-Holocene, Heinrich Stadial 1 and Last Glacial Maximum are not likely to have been more than 1 degree latitude from its present mean position. In exploring these results, we provide brief descriptions of the estimated radiation budgets of past climates that help demonstrate how different climate forcings change the interhemispheric heat balance and thus the ITCZ's global-mean position. We also address the seeming inconsistency between the small ITCZ shifts indicated by energetic constraints and the large changes in monsoon rainfall suggested by proxy data. We compare global-average and regional-scale tropical precipitation in observations and explore their responses to a variety of forcings (orbital changes, ice sheets, hosing) in models. These comparisons make clear that monsoon precipitation can change substantially even in the

  17. Significant Centers of Tectonic Activity as Identified by Wrinkle Ridges for the Western Hemisphere of Mars

    NASA Technical Reports Server (NTRS)

    Anderson, R.C.; Haldemann, A. F. C.; Golombek, M. P.; Franklin, B. J.; Dohm, J. M.; Lias, J.

    2000-01-01

    The western hemisphere region of Mars has been the site of numerous scientific investigations regarding its tectonic evolution. For this region of Mars, the dominant tectonic region is the Tharsis province. Tharsis is characterized by an enormous system of radiating grabens and a circumferential system of wrinkle ridges. Past investigations of grabens associated with Tharsis have identified specific centers of tectonic activity. A recent structural analysis of the western hemisphere region of Mars which includes the Tharsis region, utilized 25,000 structures to determine the history of local and regional centers of tectonic activity based primarily on the spatial and temporal relationships of extensional features. This investigation revealed that Tharsis is more structurally complex (heterogeneous) than has been previously identified: it consists of numerous regional and local centers of tectonic activity (some are more dominant and/or more long lived than others). Here we use the same approach as Anderson et al. to determine whether the centers of tectonic activity that formed the extensional features also contributed to wrinkle ridge (compressional) formation.

  18. Seasonality of the mean age in the UTLS region: Hemispheric differences and impact of the Asian monsoon

    NASA Astrophysics Data System (ADS)

    Konopka, Paul; Ploeger, Felix; Vogel, Bärbel; Tao, Mengchu; Müller, Rolf

    2014-05-01

    The seasonality of the composition of air in the UTLS region is determined by the seasonality of different transport processes like convection, Brewer-Dobson circulation (BDC) and two-way irreversible isentropic transport across the tropopause. Whereas during winter (seasons are related to the northern hemisphere), the subtropical jets form a strong transport barrier between the tropics and extratropics, this barrier weakens significantly in the northern hemisphere during summer. This is a result of the hemispheric asymmetry of the land-sea distribution and of the orography, which leads to hemispheric differences in the distribution and intensity of the wave drag driving the BDC. Based on a multi-annual CLaMS simulation covering the period from 2001 to 2012 with the model transport driven by the ECMWF ERA-Interim reanalysis, we discuss the seasonality of the mean age (measuring the mean transport time of an air parcel traveling from the boundary layer) in the tropical tropopause layer (TTL) and in the extratropical lowermost stratosphere (LMS). During the considered period, the simulated trace gases (like CH4, N2O, F11, CO2, CO, H2O and O3) are in fairly good agreement with in-situ and satellite observations, especially in the lower stratosphere and around the tropopause. In the TTL, the mean age shows a pronounced annual cycle that is driven by the seasonality in tropical upwelling and horizontal transport from the extratropics (inmixing) with youngest air during late boreal winter and oldest air during late boreal summer, respectively. On the other side, strong hemispheric differences can be diagnosed in the polar high latitude LMS. Here, air in the northern hemisphere is much younger during summer than during the same season on the southern hemisphere. A regionally resolved climatology of the mean age further shows youngest air in the TTL in winter above the West Pacific warm pool, whereas in summer the Asian summer monsoon forms the key pathway for transport

  19. The right hemisphere supports but does not replace left hemisphere auditory function in patients with persisting aphasia

    PubMed Central

    Barnes, Gareth R.; Penny, William D.; Iverson, Paul; Woodhead, Zoe V. J.; Griffiths, Timothy D.; Leff, Alexander P.

    2013-01-01

    In this study, we used magnetoencephalography and a mismatch paradigm to investigate speech processing in stroke patients with auditory comprehension deficits and age-matched control subjects. We probed connectivity within and between the two temporal lobes in response to phonemic (different word) and acoustic (same word) oddballs using dynamic causal modelling. We found stronger modulation of self-connections as a function of phonemic differences for control subjects versus aphasics in left primary auditory cortex and bilateral superior temporal gyrus. The patients showed stronger modulation of connections from right primary auditory cortex to right superior temporal gyrus (feed-forward) and from left primary auditory cortex to right primary auditory cortex (interhemispheric). This differential connectivity can be explained on the basis of a predictive coding theory which suggests increased prediction error and decreased sensitivity to phonemic boundaries in the aphasics’ speech network in both hemispheres. Within the aphasics, we also found behavioural correlates with connection strengths: a negative correlation between phonemic perception and an inter-hemispheric connection (left superior temporal gyrus to right superior temporal gyrus), and positive correlation between semantic performance and a feedback connection (right superior temporal gyrus to right primary auditory cortex). Our results suggest that aphasics with impaired speech comprehension have less veridical speech representations in both temporal lobes, and rely more on the right hemisphere auditory regions, particularly right superior temporal gyrus, for processing speech. Despite this presumed compensatory shift in network connectivity, the patients remain significantly impaired. PMID:23715097

  20. The right hemisphere supports but does not replace left hemisphere auditory function in patients with persisting aphasia.

    PubMed

    Teki, Sundeep; Barnes, Gareth R; Penny, William D; Iverson, Paul; Woodhead, Zoe V J; Griffiths, Timothy D; Leff, Alexander P

    2013-06-01

    In this study, we used magnetoencephalography and a mismatch paradigm to investigate speech processing in stroke patients with auditory comprehension deficits and age-matched control subjects. We probed connectivity within and between the two temporal lobes in response to phonemic (different word) and acoustic (same word) oddballs using dynamic causal modelling. We found stronger modulation of self-connections as a function of phonemic differences for control subjects versus aphasics in left primary auditory cortex and bilateral superior temporal gyrus. The patients showed stronger modulation of connections from right primary auditory cortex to right superior temporal gyrus (feed-forward) and from left primary auditory cortex to right primary auditory cortex (interhemispheric). This differential connectivity can be explained on the basis of a predictive coding theory which suggests increased prediction error and decreased sensitivity to phonemic boundaries in the aphasics' speech network in both hemispheres. Within the aphasics, we also found behavioural correlates with connection strengths: a negative correlation between phonemic perception and an inter-hemispheric connection (left superior temporal gyrus to right superior temporal gyrus), and positive correlation between semantic performance and a feedback connection (right superior temporal gyrus to right primary auditory cortex). Our results suggest that aphasics with impaired speech comprehension have less veridical speech representations in both temporal lobes, and rely more on the right hemisphere auditory regions, particularly right superior temporal gyrus, for processing speech. Despite this presumed compensatory shift in network connectivity, the patients remain significantly impaired.