Science.gov

Sample records for dividing cellular asymmetry

  1. Cellular mechanisms underlying growth asymmetry during stem gravitropism

    NASA Technical Reports Server (NTRS)

    Cosgrove, D. J.

    1997-01-01

    Plant stems respond to gravitropic stimulation with a rapid, local and reversible change in cell growth rate (elongation), generally on both the upper and lower sides of the stem. The cellular and biochemical mechanisms for this differential growth are reviewed. Considerable evidence implicates an asymmetry in wall pH in the growth response. The strengths and weaknesses of the wall "loosening enzyme" concept are reviewed and the possibility of expansin involvement in the bending response of stems is considered. Also discussed is the possibility that wall stiffening processes, e.g. phenolic coupling driven by oxidative bursts or altered orientation of newly deposited cellulose, might mediate the growth responses during gravitropism.

  2. The art of cellular communication: tunneling nanotubes bridge the divide

    PubMed Central

    Gurke, Steffen; Barroso, João F. V.

    2008-01-01

    The ability of cells to receive, process, and respond to information is essential for a variety of biological processes. This is true for the simplest single cell entity as it is for the highly specialized cells of multicellular organisms. In the latter, most cells do not exist as independent units, but are organized into specialized tissues. Within these functional assemblies, cells communicate with each other in different ways to coordinate physiological processes. Recently, a new type of cell-to-cell communication was discovered, based on de novo formation of membranous nanotubes between cells. These F-actin-rich structures, referred to as tunneling nanotubes (TNT), were shown to mediate membrane continuity between connected cells and facilitate the intercellular transport of various cellular components. The subsequent identification of TNT-like structures in numerous cell types revealed some structural diversity. At the same time it emerged that the direct transfer of cargo between cells is a common functional property, suggesting a general role of TNT-like structures in selective, long-range cell-to-cell communication. Due to the growing number of documented thin and long cell protrusions in tissue implicated in cell-to-cell signaling, it is intriguing to speculate that TNT-like structures also exist in vivo and participate in important physiological processes. PMID:18386044

  3. Hemispheric asymmetry of emotion words in a non-native mind: a divided visual field study.

    PubMed

    Jończyk, Rafał

    2015-05-01

    This study investigates hemispheric specialization for emotional words among proficient non-native speakers of English by means of the divided visual field paradigm. The motivation behind the study is to extend the monolingual hemifield research to the non-native context and see how emotion words are processed in a non-native mind. Sixty eight females participated in the study, all highly proficient in English. The stimuli comprised 12 positive nouns, 12 negative nouns, 12 non-emotional nouns and 36 pseudo-words. To examine the lateralization of emotion, stimuli were presented unilaterally in a random fashion for 180 ms in a go/no-go lexical decision task. The perceptual data showed a right hemispheric advantage for processing speed of negative words and a complementary role of the two hemispheres in the recognition accuracy of experimental stimuli. The data indicate that processing of emotion words in non-native language may require greater interhemispheric communication, but at the same time demonstrates a specific role of the right hemisphere in the processing of negative relative to positive valence. The results of the study are discussed in light of the methodological inconsistencies in the hemifield research as well as the non-native context in which the study was conducted. PMID:25300323

  4. Imperfect asymmetry: The mechanism governing asymmetric partitioning of damaged cellular components during mitosis

    PubMed Central

    Pattabiraman, Sundararaghavan; Kaganovich, Daniel

    2014-01-01

    Aging is universally associated with organism-wide dysfunction and a decline in cellular fitness. From early development onwards, the efficiency of self-repair, energy production, and homeostasis all decrease. Due to the multiplicity of systems that undergo agingrelated decline, the mechanistic basis of organismal aging has been difficult to pinpoint. At the cellular level, however, recent work has provided important insight. Cellular aging is associated with the accumulation of several types of damage, in particular damage to the proteome and organelles. Groundbreaking studies have shown that replicative aging is the result of a rejuvenation mechanism that prevents the inheritance of damaged components during division, thereby confining the effects of aging to specific cells, while removing damage from others. Asymmetric inheritance of misfolded and aggregated proteins, as well as reduced mitochondria, has been shown in yeast. Until recently, however, it was not clear whether a similar mechanism operates in mammalian cells, which were thought to mostly divide symmetrically. Our group has recently shown that vimentin establishes mitotic polarity in immortalized mammalian cells, and mediates asymmetric partitioning of multiple factors through direct interaction. These findings prompt a provocative hypothesis: that intermediate filaments serve as asymmetric partitioning modules or “sponges” that, when expressed prior to mitosis, can “clean” emerging cells of the damage they have accumulated. PMID:25941938

  5. On the effects of geometry, defects, and material asymmetry on the mechanical response of shape memory alloy cellular lattice structures

    NASA Astrophysics Data System (ADS)

    Karamooz Ravari, M. R.; Nasr Esfahani, S.; Taheri Andani, M.; Kadkhodaei, M.; Ghaei, A.; Karaca, H.; Elahinia, M.

    2016-02-01

    Shape memory alloy (such as NiTi) cellular lattice structures are a new class of advanced materials with many potential applications. The cost of fabrication of these structures however is high. It is therefore necessary to develop modeling methods to predict the functional behavior of these alloys before fabrication. The main aim of the present study is to assess the effects of geometry, microstructural imperfections and material asymmetric response of dense shape memory alloys on the mechanical response of cellular structures. To this end, several cellular and dense NiTi samples are fabricated using a selective laser melting process. Both cellular and dense specimens were tested in compression in order to obtain their stress-strain response. For modeling purposes, a three -dimensional (3D) constitutive model based on microplane theory which is able to describe the material asymmetry was employed. Five finite element models based on unit cell and multi-cell methods were generated to predict the mechanical response of cellular lattices. The results show the considerable effects of the microstructural imperfections on the mechanical response of the cellular lattice structures. The asymmetric material response of the bulk material also affects the mechanical response of the corresponding cellular structure.

  6. Digital divide: variation in internet and cellular phone use among women attending an urban sexually transmitted infections clinic.

    PubMed

    Samal, Lipika; Hutton, Heidi E; Erbelding, Emily J; Brandon, Elizabeth S; Finkelstein, Joseph; Chander, Geetanjali

    2010-01-01

    We sought to describe: (1) the prevalence of internet, cellular phone, and text message use among women attending an urban sexually transmitted infections (STI) clinic, (2) the acceptability of health advice by each mode of information and communication technology (ICT), and (3) demographic characteristics associated with ICT use. This study is a cross-sectional survey of 200 English-speaking women presenting to a Baltimore City STI clinic with STI complaints. Participants completed a self-administered survey querying ICT use and demographic characteristics. Three separate questions asked about interest in receiving health advice delivered by the three modalities: internet, cellular phone, and text message. We performed logistic regression to examine how demographic factors (age, race, and education) are associated with likelihood of using each modality. The median age of respondents was 27 years; 87% were African American, and 71% had a high school diploma. The rate of any internet use was 80%; 31% reported daily use; 16% reported weekly use; and 32% reported less frequent use. Almost all respondents (93%) reported cellular phone use, and 79% used text messaging. Acceptability of health advice by each of the three modalities was about 60%. In multivariate analysis, higher education and younger age were associated with internet use, text messaging, and cellular phone use. Overall rate of internet use was high, but there was an educational disparity in internet use. Cellular phone use was almost universal in this sample. All three modalities were equally acceptable forms of health communication. Describing baseline ICT access and the acceptability of health advice via ICT, as we have done, is one step toward determining the feasibility of ICT-delivered health interventions in urban populations. PMID:19941085

  7. Trans-Membrane Area Asymmetry Controls the Shape of Cellular Organelles

    PubMed Central

    Beznoussenko, Galina V.; Pilyugin, Sergei S.; Geerts, Willie J. C.; Kozlov, Michael M.; Burger, Koert N. J.; Luini, Alberto; Derganc, Jure; Mironov, Alexander A.

    2015-01-01

    Membrane organelles often have complicated shapes and differ in their volume, surface area and membrane curvature. The ratio between the surface area of the cytosolic and luminal leaflets (trans-membrane area asymmetry (TAA)) determines the membrane curvature within different sites of the organelle. Thus, the shape of the organelle could be critically dependent on TAA. Here, using mathematical modeling and stereological measurements of TAA during fast transformation of organelle shapes, we present evidence that suggests that when organelle volume and surface area are constant, TAA can regulate transformation of the shape of the Golgi apparatus, endosomal multivesicular bodies, and microvilli of brush borders of kidney epithelial cells. Extraction of membrane curvature by small spheres, such as COPI-dependent vesicles within the Golgi (extraction of positive curvature), or by intraluminal vesicles within endosomes (extraction of negative curvature) controls the shape of these organelles. For instance, Golgi tubulation is critically dependent on the fusion of COPI vesicles with Golgi cisternae, and vice versa, for the extraction of membrane curvature into 50–60 nm vesicles, to induce transformation of Golgi tubules into cisternae. Also, formation of intraluminal ultra-small vesicles after fusion of endosomes allows equilibration of their TAA, volume and surface area. Finally, when microvilli of the brush border are broken into vesicles and microvilli fragments, TAA of these membranes remains the same as TAA of the microvilli. Thus, TAA has a significant role in transformation of organelle shape when other factors remain constant. PMID:25761238

  8. Control of stem cell self-renewal and differentiation by the heterochronic genes and the cellular asymmetry machinery in Caenorhabditis elegans

    PubMed Central

    Harandi, Omid F.; Ambros, Victor R.

    2015-01-01

    Transitions between asymmetric (self-renewing) and symmetric (proliferative) cell divisions are robustly regulated in the context of normal development and tissue homeostasis. To genetically assess the regulation of these transitions, we used the postembryonic epithelial stem (seam) cell lineages of Caenorhabditis elegans. In these lineages, the timing of these transitions is regulated by the evolutionarily conserved heterochronic pathway, whereas cell division asymmetry is conferred by a pathway consisting of Wnt (Wingless) pathway components, including posterior pharynx defect (POP-1)/TCF, APC related/adenomatosis polyposis coli (APR-1)/APC, and LIT-1/NLK (loss of intestine/Nemo-like kinase). Here we explore the genetic regulatory mechanisms underlying stage-specific transitions between self-renewing and proliferative behavior in the seam cell lineages. We show that mutations of genes in the heterochronic developmental timing pathway, including lin-14 (lineage defect), lin-28, lin-46, and the lin-4 and let-7 (lethal defects)-family microRNAs, affect the activity of LIT-1/POP-1 cellular asymmetry machinery and APR-1 polarity during larval development. Surprisingly, heterochronic mutations that enhance LIT-1 activity in seam cells can simultaneously also enhance the opposing, POP-1 activity, suggesting a role in modulating the potency of the cellular polarizing activity of the LIT-1/POP-1 system as development proceeds. These findings illuminate how the evolutionarily conserved cellular asymmetry machinery can be coupled to microRNA-regulated developmental pathways for robust regulation of stem cell maintenance and proliferation during the course of development. Such genetic interactions between developmental timing regulators and cell polarity regulators could underlie transitions between asymmetric and symmetric stem cell fates in other systems and could be deregulated in the context of developmental disorders and cancer. PMID:25561544

  9. Morphogenesis of the node and notochord: the cellular basis for the establishment and maintenance of left-right asymmetry in the mouse

    PubMed Central

    Lee, Jeffrey D.; Anderson, Kathryn V.

    2008-01-01

    Establishment of left-right asymmetry in the mouse embryo depends on leftward laminar fluid flow in the node, which initiates a signaling cascade that is confined to the left side of the embryo. Leftward fluid flow depends on two cellular processes: motility of the cilia that generate the flow and morphogenesis of the node, the structure where the cilia reside. Here we provide an overview of the current understanding and unresolved questions about the regulation of ciliary motility and node structure. Analysis of mouse mutants has shown that the motile cilia must have a specific structure and length, and that they must point posteriorly to generate the necessary leftward fluid flow. However, the precise structure of the motile cilia is not clear and the mechanisms that position cilia on node cells have not been defined. The mouse node is a teardrop-shaped pit at the distal tip of the early embryo, but the morphogenetic events that create the mature node from cells derived from the primitive streak are only beginning to be characterized. Recent live imaging experiments support earlier scanning electron microscopy (SEM) studies and show that node assembly is a multi-step process in which clusters of node precursors appear on the embryo surface as overlying endoderm cells are removed. We present additional SEM and confocal microscopy studies that help define the transition stages during node morphogenesis. After the initiation of left-sided signaling, the notochordal plate, which is contiguous with the node, generates a barrier at the embryonic midline that restricts the cascade of gene expression to the left side of the embryo. The field is now poised to dissect the genetic and cellular mechanisms that create and organize the specialized cells of the node and midline that are essential for left-right asymmetry. PMID:18629866

  10. Valley Divide

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA03664 Valley Divide

    These small channels join to become Sabis Vallis.

    Image information: VIS instrument. Latitude -35.3N, Longitude 159.3E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  11. Why do bacteria divide?

    PubMed Central

    Norris, Vic

    2015-01-01

    The problem of not only how but also why cells divide can be tackled using recent ideas. One idea from the origins of life – Life as independent of its constituents – is that a living entity like a cell is a particular pattern of connectivity between its constituents. This means that if the growing cell were just to get bigger the average connectivity between its constituents per unit mass – its cellular connectivity – would decrease and the cell would lose its identity. The solution is division which restores connectivity. The corollary is that the cell senses decreasing cellular connectivity and uses this information to trigger division. A second idea from phenotypic diversity – Life on the Scales of Equilibria – is that a bacterium must find strategies that allow it to both survive and grow. This means that it has learnt to reconcile the opposing constraints that these strategies impose. The solution is that the cell cycle generates daughter cells with different phenotypes based on sufficiently complex equilibrium (E) and non-equilibrium (NE) cellular compounds and structures appropriate for survival and growth, respectively, alias ‘hyperstructures.’ The corollary is that the cell senses both the quantity of E material and the intensity of use of NE material and then uses this information to trigger the cell cycle. A third idea from artificial intelligence – Competitive Coherence – is that a cell selects the active subset of elements that actively determine its phenotype from a much larger set of available elements. This means that the selection of an active subset of a specific size and composition must be done so as to generate both a coherent cell state, in which the cell’s contents work together harmoniously, and a coherent sequence of cell states, each coherent with respect to itself and to an unpredictable environment. The solution is the use of a range of mechanisms ranging from hyperstructure dynamics to the cell cycle itself. PMID

  12. Why do bacteria divide?

    PubMed

    Norris, Vic

    2015-01-01

    The problem of not only how but also why cells divide can be tackled using recent ideas. One idea from the origins of life - Life as independent of its constituents - is that a living entity like a cell is a particular pattern of connectivity between its constituents. This means that if the growing cell were just to get bigger the average connectivity between its constituents per unit mass - its cellular connectivity - would decrease and the cell would lose its identity. The solution is division which restores connectivity. The corollary is that the cell senses decreasing cellular connectivity and uses this information to trigger division. A second idea from phenotypic diversity - Life on the Scales of Equilibria - is that a bacterium must find strategies that allow it to both survive and grow. This means that it has learnt to reconcile the opposing constraints that these strategies impose. The solution is that the cell cycle generates daughter cells with different phenotypes based on sufficiently complex equilibrium (E) and non-equilibrium (NE) cellular compounds and structures appropriate for survival and growth, respectively, alias 'hyperstructures.' The corollary is that the cell senses both the quantity of E material and the intensity of use of NE material and then uses this information to trigger the cell cycle. A third idea from artificial intelligence - Competitive Coherence - is that a cell selects the active subset of elements that actively determine its phenotype from a much larger set of available elements. This means that the selection of an active subset of a specific size and composition must be done so as to generate both a coherent cell state, in which the cell's contents work together harmoniously, and a coherent sequence of cell states, each coherent with respect to itself and to an unpredictable environment. The solution is the use of a range of mechanisms ranging from hyperstructure dynamics to the cell cycle itself. PMID:25932025

  13. DNA repair mechanisms in dividing and non-dividing cells

    PubMed Central

    Iyama, Teruaki; Wilson, David M.

    2013-01-01

    DNA damage created by endogenous or exogenous genotoxic agents can exist in multiple forms, and if allowed to persist, can promote genome instability and directly lead to various human diseases, particularly cancer, neurological abnormalities, immunodeficiency and premature aging. To avoid such deleterious outcomes, cells have evolved an array of DNA repair pathways, which carry out what is typically a multiple-step process to resolve specific DNA lesions and maintain genome integrity. To fully appreciate the biological contributions of the different DNA repair systems, one must keep in mind the cellular context within they operate. For example, the human body is composed of non-dividing and dividing cell types, including, in the brain, neurons and glial cells. We describe herein the molecular mechanisms of the different DNA repair pathways, and review their roles in non-dividing and dividing cells, with an eye towards how these pathways may regulate the development of neurological disease. PMID:23684800

  14. Quantifying asymmetry: ratios and alternatives.

    PubMed

    Franks, Erin M; Cabo, Luis L

    2014-08-01

    Traditionally, the study of metric skeletal asymmetry has relied largely on univariate analyses, utilizing ratio transformations when the goal is comparing asymmetries in skeletal elements or populations of dissimilar dimensions. Under this approach, raw asymmetries are divided by a size marker, such as a bilateral average, in an attempt to produce size-free asymmetry indices. Henceforth, this will be referred to as "controlling for size" (see Smith: Curr Anthropol 46 (2005) 249-273). Ratios obtained in this manner often require further transformations to interpret the meaning and sources of asymmetry. This model frequently ignores the fundamental assumption of ratios: the relationship between the variables entered in the ratio must be isometric. Violations of this assumption can obscure existing asymmetries and render spurious results. In this study, we examined the performance of the classic indices in detecting and portraying the asymmetry patterns in four human appendicular bones and explored potential methodological alternatives. Examination of the ratio model revealed that it does not fulfill its intended goals in the bones examined, as the numerator and denominator are independent in all cases. The ratios also introduced strong biases in the comparisons between different elements and variables, generating spurious asymmetry patterns. Multivariate analyses strongly suggest that any transformation to control for overall size or variable range must be conducted before, rather than after, calculating the asymmetries. A combination of exploratory multivariate techniques, such as Principal Components Analysis, and confirmatory linear methods, such as regression and analysis of covariance, appear as a promising and powerful alternative to the use of ratios. PMID:24842694

  15. Magnetic-Flux-Compensated Voltage Divider

    NASA Technical Reports Server (NTRS)

    Mata, Carlos T.

    2005-01-01

    A magnetic-flux-compensated voltage-divider circuit has been proposed for use in measuring the true potential across a component that is exposed to large, rapidly varying electric currents like those produced by lightning strikes. An example of such a component is a lightning arrester, which is typically exposed to currents of the order of tens of kiloamperes, having rise times of the order of hundreds of nanoseconds. Traditional voltage-divider circuits are not designed for magnetic-flux-compensation: They contain uncompensated loops having areas large enough that the transient magnetic fluxes associated with large transient currents induce spurious voltages large enough to distort voltage-divider outputs significantly. A drawing of the proposed circuit was not available at the time of receipt of information for this article. What is known from a summary textual description is that the proposed circuit would contain a total of four voltage dividers: There would be two mixed dividers in parallel with each other and with the component of interest (e.g., a lightning arrester), plus two mixed dividers in parallel with each other and in series with the component of interest in the same plane. The electrical and geometric configuration would provide compensation for induced voltages, including those attributable to asymmetry in the volumetric density of the lightning or other transient current, canceling out the spurious voltages and measuring the true voltage across the component.

  16. The nondeterministic divide

    NASA Technical Reports Server (NTRS)

    Charlesworth, Arthur

    1990-01-01

    The nondeterministic divide partitions a vector into two non-empty slices by allowing the point of division to be chosen nondeterministically. Support for high-level divide-and-conquer programming provided by the nondeterministic divide is investigated. A diva algorithm is a recursive divide-and-conquer sequential algorithm on one or more vectors of the same range, whose division point for a new pair of recursive calls is chosen nondeterministically before any computation is performed and whose recursive calls are made immediately after the choice of division point; also, access to vector components is only permitted during activations in which the vector parameters have unit length. The notion of diva algorithm is formulated precisely as a diva call, a restricted call on a sequential procedure. Diva calls are proven to be intimately related to associativity. Numerous applications of diva calls are given and strategies are described for translating a diva call into code for a variety of parallel computers. Thus diva algorithms separate logical correctness concerns from implementation concerns.

  17. Rethinking the Digital Divide.

    ERIC Educational Resources Information Center

    Light, Jennifer S.

    2001-01-01

    Compares the digital divide debate to debates over access to cable in the 1960s-1970s and demonstrates how access to technology is constructed as a social problem. Concludes that the current debate is different because it accepts the premise of technological determinism and assumes that closing the gap will mitigate broader social inequities.…

  18. Electronic analog divider

    NASA Technical Reports Server (NTRS)

    Birchenough, A. G. (Inventor)

    1977-01-01

    Advantage is taken of the current-exponential voltage characteristic of a diode over a certain range whereby the incremental impedance across the diode is inversely proportional to the current through the diode. Accordingly, a divider circuit employs a bias current through the diode proportional to the desired denominator and applies an incremental current to the diode proportional to the numerator. The incremental voltage across the diode is proportional to the quotient.

  19. Melting the Divide

    NASA Astrophysics Data System (ADS)

    Gibson, S. M.

    2014-12-01

    Presenting Quaternary Environmental Change to students who fall into Widening Participation criteria at the University of Cambridge, gives a unique opportunity to present academic debate in an approachable and entertaining way. Literally by discussing the melting of our ice caps, melts the divide Cambridge has between its reputation and the reality for the brightest, underprivileged, students. There is a balance between presenting cutting edge research with the need to come across as accessible (and importantly valuable to "learning"). Climate change over the Quaternary lends itself well to this aim. By lecturing groups of potential students through the entire Quaternary in an hour, stopping to discuss how our ancestors interacted with past Interglacials and what are the mechanisms driving change (in generalized terms), you are able to introduce cutting edge research (such as the latest NEEM ice core) to the students. This shows the evolution and importance of higher education and academic research. The lecture leads well onto group discussions (termed "supervisions" in Cambridge), to explore their opinions on the concern for present Anthropogenic Climate Change in relation to Past Climate Change after being presented with images that our ancestors "made it". Here discussion thrives off students saying obvious things (or sarcastic comments!) which quickly can lead into a deep technical discussion on their terms. Such discussions give the students a zest for higher education, simply throwing Ruddiman's (2003) "The Anthroprocene Started Several Thousand Years Ago" at them, questions in a second their concept of Anthropogenic Climate Change. Supervisions lend themselves well to bright, articulate, students and by offering these experiences to students of Widening Participation criteria we quickly melt the divide between the reputation of Cambridge ( and higher education as a whole) and the day to day practice. Higher education is not for the privileged, but a free and

  20. PULSE RATE DIVIDER

    DOEpatents

    McDonald, H.C. Jr.

    1962-12-18

    A compact pulse-rate divider circuit affording low impedance output and high input pulse repetition rates is described. The circuit features a single secondary emission tube having a capacitor interposed between its dynode and its control grid. An output pulse is produced at the anode of the tube each time an incoming pulse at the control grid drives the tube above cutoff and the duration of each output pulse corresponds to the charging time of the capacitor. Pulses incoming during the time the grid bias established by the discharging capacitor is sufficiently negative that the pulses are unable to drive the tube above cutoff do not produce output pulses at the anode; these pulses are lost and a dividing action is thus produced by the circuit. The time constant of the discharge path may be vanied to vary in turn the division ratio of the circuit; the time constant of the charging circuit may be varied to vary the width of the output pulses. (AEC)

  1. Monitoring the Digital Divide

    SciTech Connect

    Cottrell, Les

    2003-05-28

    It is increasingly important to support the large numbers of scientists working in remote areas and having low bandwidth access to the Internet. This will continue to be the case for years to come since there is evidence from PingER performance measurements that the, so-called, digital divide is not decreasing. In this work, we review the collaborative work of The Abdus Salam International Center for Theoretical Physics (ICTP) in Trieste, a leading organization promoting science dissemination in the developing world- and SLAC in Stanford, to monitor by PingER, Universities and Research Institutions all over the developing world following the recent ''Recommendations of Trieste'' to help bridge the digital divide. As a result, PingER's deployment now covers the real-time monitoring of worldwide Internet performance and, in particular, West and Central Africa for the first time. We report on the results from the ICTP sites and quantitatively identify regions with poor performance, identify trends, discuss experiences and future work.

  2. Laser dividing apparatus

    DOEpatents

    English, Jr., R. Edward; Johnson, Steve A.

    1995-01-01

    A laser beam dividing apparatus (10) having a first beam splitter (14) with an aperture (16) therein positioned in the path of a laser beam (12) such that a portion of the laser beam (12) passes through the aperture (16) onto a second beam splitter (20) and a portion of the laser beam (12) impinges upon the first beam splitter (14). Both the first beam splitter (14) and the second beam splitter (20) are, optionally, made from a dichroic material such that a green component (24) of the laser beam (12) is reflected therefrom and a yellow component (26) is refracted therethrough. The first beam splitter (14) and the second beam splitter (20) further each have a plurality of facets (22) such that the components (24, 26) are reflected and refracted in a number equaling the number of facets (22).

  3. Shifts that divide population

    NASA Astrophysics Data System (ADS)

    Muneepeerakul, Rachata; Qubbaj, Murad; Aggarwal, Rimjhim; Anderies, John M.; Janssen, Marco

    2014-05-01

    How does a population of organisms in an ecosystem or of people in a society respond to rapid shifts in the environment? Answers to this question are critical to our ability to anticipate and cope with a changing ecohydrological system. We have developed a generic model of adaptation mechanisms, based on replicator dynamics, in which we derive a simple and insightful threshold condition that separates two important types of responses: 'cohesive transition' in which the whole population changes gradually together, and 'population-dividing transition' in which the population splits into two groups with one eventually dominating the other. The threshold depends on the magnitude of the shift and the shape of the fitness landscape. Division in populations can fundamentally alter the functioning of and induce subsequent feedbacks within the system; knowing the condition that gives rise to such division is thus fundamentally important.

  4. Chaos, brain and divided consciousness.

    PubMed

    Bob, Petr

    2007-01-01

    Modern trends in psychology and cognitive neuroscience suggest that applications of nonlinear dynamics, chaos and self-organization seem to be particularly important for research of some fundamental problems regarding mind-brain relationship. Relevant problems among others are formations of memories during alterations of mental states and nature of a barrier that divides mental states, and leads to the process called dissociation. This process is related to a formation of groups of neurons which often synchronize their firing patterns in a unique spatial maner. Central theme of this study is the relationship between level of moving and oscilating mental processes and their neurophysiological substrate. This opens a question about principles of organization of conscious experiences and how these experiences arise in the brain. Chaotic self-organization provides a unique theoretical and experimental tool for deeper understanding of dissociative phenomena and enables to study how dissociative phenomena can be linked to epileptiform discharges which are related to various forms of psychological and somatic manifestations. Organizing principles that constitute human consciousness and other mental phenomena from this point of view may be described by analysis and reconstruction of underlying dynamics of psychological or psychophysiological measures. These nonlinear methods in this study were used for analysis of characteristic changes in EEG and bilateral electrodermal activity (EDA) during reliving of dissociated traumatic and stressful memories and during psychopathological states. Analysis confirms a possible role of chaotic transitions in the processing of dissociated memory. Supportive finding for a possible chaotic process related to dissociation found in this study represent also significant relationship of dissociation, epileptiform discharges measured by typical psychopathological manifestations and characteristic laterality changes in bilateral EDA in patients

  5. What’s Left in Asymmetry?

    PubMed Central

    Aw, Sherry

    2008-01-01

    Left-right patterning is a fascinating problem of morphogenesis, linking evolutionary and cellular signaling mechanisms across many levels of organization. In the last 15 years, enormous progress has been made in elucidating the molecular details of this process in embryos of several model species. While many outside the field seem to believe that the fundamental aspects of this pathway are now solved, workers on asymmetry are faced with considerable uncertainties over the details of specific mechanisms, a lack of conceptual unity of mechanisms across phyla, and important questions that are not being pursued in any of the popular model systems. Here, we suggest that data from clinical syndromes, cryptic asymmetries, and bilateral gynandromorphs, while not figuring prominently in the mainstream work on LR asymmetry, point to crucial and fundamental gaps of knowledge about asymmetry. We identify 12 big questions that provide exciting opportunities for fundamental new advances in this field. PMID:18488999

  6. Challenging the Digital Divide

    NASA Astrophysics Data System (ADS)

    Kembhavi, Ajit

    2006-08-01

    Vast quantities of astronomical data in the form of images, spectra and catalogues are now freely available over the internet, and tools for producing science from these resources are also becoming available, particularly through the emerging Virtual Observatories. In addition to this, most astronomical literature from research journals is available at no cost through the ADS and preprint service. This situation, in principle, provides equal opportunity to astronomers located anywhere in the world to participate in the process of discovery. The only requirement is that the astronomers have access to the internet, and a fertile imagination. But in the real world, astronomers in many countries have very limited bandwidth and computing power, and are therefore excluded from meaningful participation in astronomical research, even though they may have the ideas and experience to contribute substantially to the effort. The lack of connectivity and computing hardware also makes it difficult for astronomers in many countries from exposing adequately any data resources that they may have produced locally. This situation prevents many aspiring and experienced astronomers from reaching their creative potential, and from attracting young persons to the charms of modern astronomy; it also leads to opportunity loss to astronomy, as it loses out on the the human resources and fresh ideas and talents which astronomers from developing countries could bring to the subject. I will discuss in my talk the nature and extent of this digital divide, the ways in which it could be mitigated, and the benefits which would arise from the unification. I will base some of my discussion on my experiences in setting up a major programme to take the advantages of the internet revolution to hundreds of universities in India.

  7. Fish otolith asymmetry: morphometry and modeling.

    PubMed

    Lychakov, D V; Rebane, Y T; Lombarte, A; Fuiman, L A; Takabayashi, A

    2006-09-01

    Mathematical modeling suggests that relatively large values of otolith mass asymmetry in fishes can alter acoustic functionality and may be responsible for abnormal fish behavior when subjected to weightlessness during parabolic or space flight [D.V. Lychakov, Y.T. Rebane, Otolith mass asymmetry in 18 species of fish and pigeon, J. Grav. Physiol. 11 (3) (2004) 17-34; D.V. Lychakov, Y.T. Rebane, Fish otolith mass asymmetry: morphometry and influence on acoustic functionality, Hear. Res. 201 (2005) 55-69]. The results of morphometric studies of otolith mass asymmetry suppose that the absolute value and the sign of the otolith mass asymmetry can change many times during the growth of individual fish within the range +/-20% [D.V. Lychakov, Y.T. Rebane, Otolith mass asymmetry in 18 species of fish and pigeon, J. Grav. Physiol. 11 (3) (2004) 17-34; D.V. Lychakov, Y.T. Rebane, Fish otolith mass asymmetry: morphometry and influence on acoustic functionality, Hear. Res. 201 (2005) 55-69]. This implies that the adverse effects of otolith asymmetry on acoustic and vestibular functionality could change during the lifetime of an individual fish. The aims of the present article were to examine the nature of otolith mass asymmetry fluctuation and to quantify otolith mass asymmetry in a large number of teleost fishes to verify our previous measurements. A dimensionless measure of otolith mass asymmetry, chi, was calculated as the difference between the masses of the right and left paired otoliths divided by average otolith mass. Saccular otolith mass asymmetry was studied in 59 Mediterranean teleost species (395 otolith pairs), 14 Black Sea teleost species (42 otolith pairs), red drum (196 otolith pairs) and guppy (30 otolith pairs). Utricular otolith mass asymmetry was studied in carp (103 otolith pairs) and goldfish (45 otolith pairs). In accordance with our previous results the value of chi did not depend on fish size (length or mass), systematic or ecological position of the

  8. Structural Asymmetry of Anterior Insula: Behavioral Correlates and Individual Differences

    PubMed Central

    Chiarello, Christine; Vazquez, David; Felton, Adam; Leonard, Christiana M.

    2013-01-01

    The current study investigated behavioral correlates of structural asymmetry of the insula, and traditional perisylvian language regions, in a large sample of young adults (N=200). The findings indicated 1) reliable leftward surface area asymmetry of the anterior insula, 2) association of this asymmetry with divided visual field lateralization of visual word recognition, and 3) modulation of the correlation of structural and linguistic asymmetry by consistency of hand preference. Although leftward asymmetry of cortical surface area was observed for the anterior insula, pars opercularis and triangularis, and planum temporale, only the anterior insula asymmetry was associated with lateralized word recognition. We interpret these findings within the context of recent structural and functional findings about the human insula. We suggest that leftward structural lateralization of earlier developing insular cortex may bootstrap asymmetrical functional lateralization even if the insula is only a minor component of the adult language network. PMID:23681069

  9. Broca's area: nomenclature, anatomy, typology and asymmetry.

    PubMed

    Keller, Simon S; Crow, Timothy; Foundas, Anne; Amunts, Katrin; Roberts, Neil

    2009-04-01

    In this review, we (i) describe the nomenclature of Broca's area and show how the circumscribed definition of Broca's area is disassociated from Broca's aphasia, (ii) describe in detail how the gross anatomy of Broca's area varies between people, and how the definitions vary between studies, (iii) attempt to reconcile the findings of structural asymmetry of Broca's area with the differences in methodological approaches, (iv) consider the functional significance of cytoarchitectonic definitions of Broca's area, and (v) critically elucidate the significance of circumscribed regions of cortex for language lateralisation and language development. Contrary to what has previously been reported in the literature, asymmetry of Broca's area has not been reproducibly demonstrated, particularly on a gross morphological level. This may be due to major inconsistencies in methodology (including different anatomical boundaries, measurement techniques and samples studied) or that the sulcal contours defining Broca's area are so naturally variable between people making a standard definition difficult. Cytoarchitectonic analyses more often than not report leftward asymmetry of some component of area 44 and/or area 45. If a structural asymmetry of Broca's area does exist, it is variable, which differs from that of the functional asymmetry of language, which is more consistent. One reason for this might be that the link between cellular architecture, connectivity and language function still remains to be elucidated. There is currently no convincing explanation to associate asymmetry of Broca's area with the lateralisation of language. PMID:19155059

  10. The Digital Divide: A Global View

    NASA Astrophysics Data System (ADS)

    Ntoko, Alexander

    2011-04-01

    Huge progress was made in bridging the digital divide in first decade of 21^st century. This was largely due to the explosive growth of mobile, which saw numbers rise from under 500 million to over five billion mobile cellular subscriptions in just ten years. With household mobile penetration rates of over 50% even in rural areas of developing countries, we have achieved the dream of bringing all the world's people within reach of communications technology. We must now, however, replicate the mobile miracle for the Internet, and especially broadband, if we are to avoid creating a new broadband breach to replace the digital divide. Three things need to happen for this to be achieved: firstly, broadband needs to be brought to the top of the development agenda; secondly, broadband needs to become much more affordable and thirdly, security needs to be part of the strategy.

  11. Fluctuating Asymmetry and Intelligence

    ERIC Educational Resources Information Center

    Bates, Timothy C.

    2007-01-01

    The general factor of mental ability ("g") may reflect general biological fitness. If so, "g"-loaded measures such as Raven's progressive matrices should be related to morphological measures of fitness such as fluctuating asymmetry (FA: left-right asymmetry of a set of typically left-right symmetrical body traits such as finger lengths). This…

  12. Essays on the Digital Divide

    ERIC Educational Resources Information Center

    Abdelfattah, Belal M. T.

    2013-01-01

    The digital divide is a phenomenon that is globally persistent, despite rapidly decreasing costs in technology. While much of the variance in the adoption and use of information communication technology (ICT) that defines the digital divide can be explained by socioeconomic and demographic variables, there is still significant unaccounted variance…

  13. The pesky power asymmetry

    NASA Astrophysics Data System (ADS)

    Dai, Liang; Jeong, Donghui; Kamionkowski, Marc; Chluba, Jens

    2013-06-01

    Physical models for the hemispherical power asymmetry in the cosmic microwave background (CMB) reported by the Planck Collaboration must satisfy CMB constraints to the homogeneity of the Universe and quasar constraints to power asymmetries. We survey a variety of models for the power asymmetry and show that consistent models include a modulated scale-dependent isocurvature contribution to the matter power spectrum or a modulation of the reionization optical depth, gravitational-wave amplitude, or scalar spectral index. We propose further tests to distinguish between the different scenarios.

  14. Sociology: The growing climate divide

    NASA Astrophysics Data System (ADS)

    Hoffman, Andrew J.

    2011-07-01

    Climate change has reached the level of a 'scientific consensus', but is not yet a 'social consensus'. New analysis highlights that a growing divide between liberals and conservatives in the American public is a major obstacle to achieving this end.

  15. Divided loyalties and ambiguous relationships.

    PubMed

    Toulmin, S

    1986-01-01

    The author argues that conflicts of obligation may, but need not, give rise to issues of divided loyalties. Given this, the question then becomes under what circumstances and conditions a simple internal conflict may escalate into the problem of divided loyalties or fiduciary ambiguities. After discussing conflicts of obligation, it is asserted that loyalties are divided only when the demands of the various relationships involved are irreconcilable. As this is an extreme, the major problematic issues fall, then, in between, on multiple loyalties and ambiguous loyalties. How and where multiple loyalties arise, and under what conditions they may become ambiguous loyalties lead to the recognition that moral problems are created by leaving in ambiguity things about the relationships involved that would be better sorted out. Finally the author looks at situations in which physicians are systematically exposed to irresoluble ambiguity. PMID:3798158

  16. Getting Past the "Digital Divide"

    ERIC Educational Resources Information Center

    McCollum, Sean

    2011-01-01

    In the last decade, "digital divide" has become a catchphrase for the stubborn disparity in IT resources between communities, especially in regard to education. Low-income, rural and minority populations have received special scrutiny as the technological "have-nots." This article presents success stories of educators who can work around obstacles…

  17. Dividing Fractions: A Pedagogical Technique

    ERIC Educational Resources Information Center

    Lewis, Robert

    2016-01-01

    When dividing one fraction by a second fraction, invert, that is, flip the second fraction, then multiply it by the first fraction. To multiply fractions, simply multiply across the denominators, and multiply across the numerators to get the resultant fraction. So by inverting the division of fractions it is turned into an easy multiplication of…

  18. Getting Past the "Digital Divide"

    ERIC Educational Resources Information Center

    McCollum, Sean

    2011-01-01

    As most educators know, there is a lot more to addressing the so-called "digital divide" than having enough working machines in classrooms. Effective information technology (IT) in schools requires useful software, reliable and speedy Internet access, effective teacher training, and well-considered goals with transformative outcomes. Educators who…

  19. Asymmetry through time dependency

    NASA Astrophysics Data System (ADS)

    Mantzaris, Alexander V.; Higham, Desmond J.

    2016-03-01

    Given a single network of interactions, asymmetry arises when the links are directed. For example, if protein A upregulates protein B and protein B upregulates protein C, then (in the absence of any further relationships between them) A may affect C but not vice versa. This type of imbalance is reflected in the associated adjacency matrix, which will lack symmetry. A different type of imbalance can arise when interactions appear and disappear over time. If A meets B today and B meets C tomorrow, then (in the absence of any further relationships between them) A may pass a message or disease to C, but not vice versa. Hence, even when each interaction is a two-way exchange, the effect of time ordering can introduce asymmetry. This observation is very closely related to the fact that matrix multiplication is not commutative. In this work, we describe a method that has been designed to reveal asymmetry in static networks and show how it may be combined with a measure that summarizes the potential information flow between nodes in the temporal case. This results in a new method that quantifies the asymmetry arising through time ordering. We show by example that the new tool can be used to visualize and quantify the amount of asymmetry caused by the arrow of time.

  20. Nuclear asymmetry enthalpy

    SciTech Connect

    Sobotka, L. G.

    2011-07-15

    Recent work has sought to extract the asymmetry energy at very low density from observables in heavy-ion collisions. The logic employed starts from the assumption that the fragment yields are determined by a minimization of the Helmholtz free energy. As volume is in reality unconstrained, nor can a single freeze-out volume be expected, the physical relevance of the Helmholtz free energy must be questioned. If, for example, the identical logic were used, but the Gibbs free energy was the more relevant quantity to minimize, it would be the asymmetry enthalpy that would be extracted. The purpose of this report is to provide one measure of the difference between the asymmetry energy and enthalpy.

  1. Electroweak asymmetries from SLD

    SciTech Connect

    Bellodi, G.

    2002-06-01

    We present a summary of the results on electroweak asymmetries performed by the SLD experiment at the Stanford Linear Collider (SLC). Most of these results are final and are based, unless otherwise stated, on the full 1993-1998 data set of approximately 550,000 hadronic decays of Z{sup 0} bosons, produced with an average electron beam polarization of 73%.

  2. TRANSVERSITY SINGLE SPIN ASYMMETRIES.

    SciTech Connect

    BOER,D.

    2001-04-27

    The theoretical aspects of two leading twist transversity single spin asymmetries, one arising from the Collins effect and one from the interference fragmentation functions, are reviewed. Issues of factorization, evolution and Sudakov factors for the relevant observables are discussed. These theoretical considerations pinpoint the most realistic scenarios towards measurements of transversity.

  3. Wealth and the marital divide.

    PubMed

    Schneider, Daniel

    2011-09-01

    Marriage patterns differ dramatically in the United States by race and education. The author identifies a novel explanation for these marital divides, namely, the important role of personal wealth in marriage entry. Using event-history models and data from the National Longitudinal Survey of Youth 1979 cohort, the author shows that wealth is an important predictor of first marriage and that differences in asset ownership by race and education help to explain a significant portion of the race and education gaps in first marriage. The article also tests possible explanations for why wealth plays an important role in first marriage entry. PMID:22268248

  4. A house divided cannot stand

    SciTech Connect

    Gilbert, S.M. )

    1994-01-01

    When it comes to the relationships between electric utilities and public service commissions, utilities would do well to remember the words of Abraham Lincoln -- [open quotes]A house divided against itself cannot stand.[close quotes] For just as distrust, dissension, and division threatened the future of the United States during the Civil War, they threaten the future of utilities today.In an effort to lower their costs and increase their competitive advantage, utility companies are increasingly looking to reinvent cultures, reengineer work processes, and redefine corporate missions, values, and strategies. But unless utilities also rebuild regulatory relations, such efforts are doomed to fail. If this prognosis sounds overly simplistic or melodramatic -- especially as utilities appear to be moving toward an era of reduced regulation -- think again. History shows that regulatory relationships drive a utility's ability to successfully integrate demand-side management (DSM) programs that are often critical to business strategies and goals.

  5. Extent of structural asymmetry in homodimeric proteins: prevalence and relevance.

    PubMed

    Swapna, Lakshmipuram Seshadri; Srikeerthana, Kuchi; Srinivasan, Narayanaswamy

    2012-01-01

    Most homodimeric proteins have symmetric structure. Although symmetry is known to confer structural and functional advantage, asymmetric organization is also observed. Using a non-redundant dataset of 223 high-resolution crystal structures of biologically relevant homodimers, we address questions on the prevalence and significance of asymmetry. We used two measures to quantify global and interface asymmetry, and assess the correlation of several molecular and structural parameters with asymmetry. We have identified rare cases (11/223) of biologically relevant homodimers with pronounced global asymmetry. Asymmetry serves as a means to bring about 2:1 binding between the homodimer and another molecule; it also enables cellular signalling arising from asymmetric macromolecular ligands such as DNA. Analysis of these cases reveals two possible mechanisms by which possible infinite array formation is prevented. In case of homodimers associating via non-topologically equivalent surfaces in their tertiary structures, ligand-dependent mechanisms are used. For stable dimers binding via large surfaces, ligand-dependent structural change regulates polymerisation/depolymerisation; for unstable dimers binding via smaller surfaces that are not evolutionarily well conserved, dimerisation occurs only in the presence of the ligand. In case of homodimers associating via interaction surfaces with parts of the surfaces topologically equivalent in the tertiary structures, steric hindrance serves as the preventive mechanism of infinite array. We also find that homodimers exhibiting grossly symmetric organization rarely exhibit either perfect local symmetry or high local asymmetry. Binding of small ligands at the interface does not cause any significant variation in interface asymmetry. However, identification of biologically relevant interface asymmetry in grossly symmetric homodimers is confounded by the presence of similar small magnitude changes caused due to artefacts of

  6. Lunar asymmetry and palaeomagnetism

    NASA Astrophysics Data System (ADS)

    Stevenson, D. J.

    1980-10-01

    A model is proposed for the early lunar evolution which accounts for the compositional asymmetry between the nearside and farside of the moon and the natural remanent magnetism of lunar rocks. According to the model, the preferred gravitational energy state consisted of an asymmetric accumulation of a liquid iron alloy (Fe-Ni and a small amount of sulfur) which displaces upwards the cold primordial undifferentiated core. The resulting depth asymmetry of the outer partially molten zone leads eventually to the subcrustal accumulation of light magnesium-rich pyroxenes and olivine, preferentially in one hemisphere, sufficient to explain the offset and also indirectly providing a possible explanation for the nearside concentration of KREEP and mass basalt. Slow downward migration of iron releases gravitational energy sufficient for convection and dynamo generation in an iron layer for about a billion years.

  7. A Justifiable Asymmetry.

    PubMed

    Brudney, Daniel; Siegler, Mark

    2015-01-01

    It is a clinician's cliché that a physician only challenges a patient's capacity to make a treatment decision if that decision is not what the physician wants. Agreement is proof of decisional capacity; disagreement is proof or at least evidence of capacity's absence. It is assumed that this asymmetry cannot be justified, that the asymmetry must be a form of physicians' paternalism. Instead what is at issue when patient and physician disagree are usually two laudable impulses. The first is physicians' commitment to patients' well-being: physicians have a professional obligation as well as, ideally, a personal commitment to take care of patients--to do their best to bring about a positive medical outcome. The second impulse is common to much of human life, namely, the urge to find and to understand the source of our disagreements with one another. In this article we argue that, jointly, these impulses justify the asymmetry with regard to examining patients' capacity. PMID:26132055

  8. Hidden asymmetry of ice.

    PubMed

    Kirov, Mikhail V

    2014-11-26

    Ice is a very complex and fundamentally important solid. In the present article, we review a new property of the hydrogen-bonded network in ice structures: an explicit nonequivalence of some antipodal configurations with the opposite direction of all hydrogen bonds (H-bonds). This asymmetry is most pronounced for the structures with considerable deviation of the H-bond network from the tetrahedral coordination. That is why we have investigated in detail four-coordinated ice nanostructures with no outer "dangling" hydrogen atoms, namely, ice bilayers and ice nanotubes consisting of stacked n-membered rings. The reason for this H-bonding asymmetry is a fundamental nonequivalence of the arrangements of water molecules in some antipodal configurations with the opposite direction of all H-bonds. For these configurations, the overall pictures of deviations of the hydrogen bonds from linearity are qualitatively different. We consider the reversal of all H-bonds as an additional nongeometric operation of symmetry, more precisely antisymmetry. It is not easy to find the explicit breaking of the symmetry of hydrogen bonding (H-symmetry) in the variety of all configurations. Therefore, this asymmetry may be named hidden. PMID:24905908

  9. Facial asymmetry: a current review

    PubMed Central

    Thiesen, Guilherme; Gribel, Bruno Frazão; Freitas, Maria Perpétua Mota

    2015-01-01

    Abstract The term "asymmetry" is used to make reference to dissimilarity between homologous elements, altering the balance between structures. Facial asymmetry is common in the overall population and is often presented subclinically. Nevertheless, on occasion, significant facial asymmetry results not only in functional, but also esthetic issues. Under these conditions, its etiology should be carefully investigated in order to achieve an adequate treatment plan. Facial asymmetry assessment comprises patient's first interview, extra- as well as intraoral clinical examination, and supplementary imaging examination. Subsequent asymmetry treatment depends on patient's age, the etiology of the condition and on the degree of disharmony, and might include from asymmetrical orthodontic mechanics to orthognathic surgery. Thus, the present study aims at addressing important aspects to be considered by the orthodontist reaching an accurate diagnosis and treatment plan of facial asymmetry, in addition to reporting treatment of some patients carriers of such challenging disharmony. PMID:26691977

  10. (Bessel-) weighted asymmetries

    SciTech Connect

    Bernhard Musch, Alexey Prokudin

    2011-11-01

    Semi-inclusive deep inelastic scattering experiments allow us to probe the motion of quarks inside the proton in terms of so-called transverse momentum dependent parton distribution functions (TMD PDFs), but the information is convoluted with fragmentation functions (TMD FFs) and soft factors. It has long been known that weighting the measured event counts with powers of the hadron momentum before forming angular asymmetries de-convolutes TMD PDFs and TMD FFs in an elegant way, but this also entails an undesirable sensitivity to high momentum contributions. Using Bessel functions as weights, we find a natural generalization of weighted asymmetries that preserves the de-convolution property and features soft-factor cancellation, yet allows us to be less sensitive to high transverse momenta. The formalism also relates to TMD quantities studied in lattice QCD. We briefly show preliminary lattice results from an exploratory calculation of the Boer-Mulders shift using lattices generated by the MILC and LHP collaborations at a pion mass of 500 MeV.

  11. Facial asymmetry in ocular torticollis.

    PubMed

    Akbari, Mohammad Reza; Khorrami Nejad, Masoud; Askarizadeh, Farshad; Pour, Fatemeh Farahbakhsh; Ranjbar Pazooki, Mahsa; Moeinitabar, Mohamad Reza

    2015-01-01

    Torticollis can arise from nonocular (usually musculoskeletal) and ocular conditions. Some facial asymmetries are correlated with a history of early onset ocular torticollis supported by the presence of torticollis on reviewing childhood photographs. When present in an adult, this type of facial asymmetry with an origin of ocular torticollis should help to confirm the chronicity of the defect and prevent unnecessary neurologic evaluation in patients with an uncertain history. Assessment of facial asymmetry consists of a patient history, physical examination, and medical imaging. Medical imaging and facial morphometry are helpful for objective diagnosis and measurement of the facial asymmetry, as well as for treatment planning. The facial asymmetry in congenital superior oblique palsy is typically manifested by midfacial hemihypoplasia on the side opposite the palsied muscle, with deviation of the nose and mouth toward the hypoplastic side. Correcting torticollis through strabismus surgery before a critical developmental age may prevent the development of irreversible facial asymmetry. Mild facial asymmetry associated with congenital torticollis has been reported to resolve with continued growth after early surgery, but if asymmetry is severe or is not treated in the appropriate time, it might remain even with continued growth after surgery. PMID:27239567

  12. Lepton forward-backward asymmetries

    SciTech Connect

    Pain, R. ); DELPHI Collaboration,

    1992-02-01

    Results of Forward-Backward Asymmetries with Leptons measured at [ital Z][sup 0] energies are presented. Details of the analysis by the DELPHI Collaboration are given together with the most recent values of the peak Asymmetries for electrons, muons, and taus obtained by ALEPH, DELPHI, L3, and OPAL Collaborations at LEP.

  13. Asymmetry In Biphase Data Signals

    NASA Technical Reports Server (NTRS)

    Nguyen, Tien M.

    1992-01-01

    Report presents analysis of some effects of asymmetry in Manchester (biphase) binary data signal transmitted by phase modulation of sinusoidal carrier signal. Report extends analysis described in article, "Effects of Asymmetry of NRZ Data Signals on Performance" (NPO-18261), to include case where data biphase-modulated directly on residual carrier.

  14. Diversity, Disability, and Geographic Digital Divide

    ERIC Educational Resources Information Center

    Sumari, Melati; Carr, Erika; Ndebe-Ngovo, Manjerngie

    2006-01-01

    The phenomenon called digital divide was the focus of this paper. Diversity, disability, and geographical digital divide were relevant to this collaborative project. An extensive review of the literature was conducted for the completion of this project. The evidence for the digital divide in terms of race, level of education, and gender in the…

  15. Tech, Teachers & Teens: Bridging the Divide

    ERIC Educational Resources Information Center

    Stuht, Amy Colcord; Colcord, Cean

    2011-01-01

    In past decades, the "digital divide" referred to the gap between those who could afford access to technology and those who could not. The divide has shifted in recent years to reflect the growing technological chasm between teachers and their students: today's schools and teenagers' worlds. The digital divide is widening and deepening…

  16. The Myth about the Digital Divide

    ERIC Educational Resources Information Center

    Hawkins, Brian L.; Oblinge, Diana G.

    2006-01-01

    Although computer ownership is not 100 percent, progress has been made on closing the digital divide. However, defining the digital divide according to the haves and have-nots of computer ownership is only a starting point. Beyond computer ownership, colleges and universities should explore the "second-level digital divide," which can be caused by…

  17. Power Divider for Waveforms Rich in Harmonics

    NASA Technical Reports Server (NTRS)

    Sims, William Herbert, III

    2005-01-01

    A method for dividing the power of an electronic signal rich in harmonics involves the use of an improved divider topology. A divider designed with this topology could be used, for example, to propagate a square-wave signal in an amplifier designed with a push-pull configuration to enable the generation of more power than could be generated in another configuration.

  18. 40 CFR 1065.248 - Gas divider.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... blends gases to the specifications of § 1065.750 and to the flow-weighted concentrations expected during testing. You may use critical-flow gas dividers, capillary-tube gas dividers, or thermal-mass-meter gas... PROCEDURES Measurement Instruments Flow-Related Measurements § 1065.248 Gas divider. (a) Application. You...

  19. 40 CFR 1065.248 - Gas divider.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... blends gases to the specifications of § 1065.750 and to the flow-weighted concentrations expected during testing. You may use critical-flow gas dividers, capillary-tube gas dividers, or thermal-mass-meter gas... PROCEDURES Measurement Instruments Flow-Related Measurements § 1065.248 Gas divider. (a) Application. You...

  20. 40 CFR 1065.248 - Gas divider.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... blends gases to the specifications of § 1065.750 and to the flow-weighted concentrations expected during testing. You may use critical-flow gas dividers, capillary-tube gas dividers, or thermal-mass-meter gas... PROCEDURES Measurement Instruments Flow-Related Measurements § 1065.248 Gas divider. (a) Application. You...

  1. 40 CFR 1065.248 - Gas divider.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... blends gases to the specifications of § 1065.750 and to the flow-weighted concentrations expected during testing. You may use critical-flow gas dividers, capillary-tube gas dividers, or thermal-mass-meter gas... PROCEDURES Measurement Instruments Flow-Related Measurements § 1065.248 Gas divider. (a) Application. You...

  2. 40 CFR 1065.248 - Gas divider.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... blends gases to the specifications of § 1065.750 and to the flow-weighted concentrations expected during testing. You may use critical-flow gas dividers, capillary-tube gas dividers, or thermal-mass-meter gas... PROCEDURES Measurement Instruments Flow-Related Measurements § 1065.248 Gas divider. (a) Application. You...

  3. Measurements of W Charge Asymmetry

    SciTech Connect

    Holzbauer, J. L.

    2015-10-06

    We discuss W boson and lepton charge asymmetry measurements from W decays in the electron channel, which were made using 9.7 fb$^{-1}$ of RunII data collected by the D0 detector at the Fermilab Tevatron Collider. The electron charge asymmetry is presented as a function of pseudo-rapidity out to |$\\eta$| $\\le$ 3.2, in five symmetric and asymmetric kinematic bins of electron transverse momentum and the missing transverse energy of the event. We also give the W charge asymmetry as a function of W boson rapidity. The asymmetries are compared with next-to-leading order perturbative quantum chromodynamics calculations. These charge asymmetry measurements will allow more accurate determinations of the proton parton distribution functions and are the most precise to date.

  4. Lateral cephalometric diagnosis of asymmetry in Angle Class II subdivision compared to Class I and II

    PubMed Central

    Meloti, Aparecida Fernanda; Gonçalves, Renata de Cássia; Silva, Ertty; Martins, Lídia Parsekian; dos Santos-Pinto, Ary

    2014-01-01

    Introduction Lateral cephalometric radiographs are traditionally required for orthodontic treatment, yet rarely used to assess asymmetries. Objective The objective of the present study was to use lateral cephalometric radiographs to identify existing skeletal and dentoalveolar morphological alterations in Class II subdivision and to compare them with the existing morphology in Class I and II relationship. Material and Methods Ninety initial lateral cephalometric radiographs of male and female Brazilian children aged between 12 to 15 years old were randomly and proportionally divided into three groups: Group 1 (Class I), Group 2 (Class II) and Group 3 (Class II subdivision). Analysis of lateral cephalometric radiographs included angular measurements, horizontal linear measurements and two indexes of asymmetry that were prepared for this study. Results In accordance with an Index of Dental Asymmetry (IDA), greater mandibular dental asymmetry was identified in Group 3. An Index of Mandibular Asymmetry (IMA) revealed less skeletal and dental mandibular asymmetry in Group 2, greater skeletal mandibular asymmetry in Group 1, and greater mandibular dental asymmetry in Group 3. Conclusion Both IDA and IMA revealed greater mandibular dental asymmetry for Group 3 in comparison to Groups 1 and 2. These results are in accordance with those found by other diagnostic methods, showing that lateral cephalometric radiography is an acceptable method to identify existing skeletal and dentoalveolar morphological alterations in malocclusions. PMID:25279525

  5. Fluctuating asymmetry and testing isolation of Montana grizzly bear populations

    USGS Publications Warehouse

    Picton, Harold D.; Palmisciano, D.A.; Nelson, Gerald

    1990-01-01

    Fluctuating asymmetry of adult skulls was used to test he genetic isolation of the Yellowstone grizzly bear population from its nearest neighbor. An overall summary statistic was used in addition to 16 other parameters. Tests found the males of the Yellowstone populaion to be more vaiable than those of the North Conitinental Divide Exosystem. Evidence for precipitaiton effects is also included. This test tends to support the existing management haypothesis that the Yellowstone population is isolatied.

  6. Baryon asymmetry and split SUSY

    SciTech Connect

    Kasuya, Shinta

    2005-12-02

    It is one of the greatest mysteries that the baryon asymmetry in our universe is so small. It is argued that it may originate from some profound physics beyond the standard model. We investigate the Affleck-Dine baryogenesis in split supersymmetry, and find that the smallness of the baryon asymmetry is directly related to the hierarchy between the supersymmetry breaking squark/slepton masses and the weak scale. Put simply, the baryon asymmetry is small because of the split mass spectrum. LHC may prove or falsify our scenario.

  7. Decision making in noisy bistable systems with time-dependent asymmetry

    NASA Astrophysics Data System (ADS)

    Nené, Nuno R.; Zaikin, Alexey

    2013-01-01

    Our work draws special attention to the importance of the effects of time-dependent parameters on decision making in bistable systems. Here, we extend previous studies of the mechanism known as speed-dependent cellular decision making in genetic circuits by performing an analytical treatment of the canonical supercritical pitchfork bifurcation problem with an additional time-dependent asymmetry and control parameter. This model has an analogous behavior to the genetic switch. In the presence of transient asymmetries and fluctuations, slow passage through the critical region in both systems increases substantially the probability of specific decision outcomes. We also study the relevance for attractor selection of reaching maximum values for the external asymmetry before and after the critical region. Overall, maximum asymmetries should be reached at an instant where the position of the critical point allows for compensation of the detrimental effects of noise in retaining memory of the transient asymmetries.

  8. CMB maximum temperature asymmetry axis: Alignment with other cosmic asymmetries

    NASA Astrophysics Data System (ADS)

    Mariano, Antonio; Perivolaropoulos, Leandros

    2013-02-01

    We use a global pixel-based estimator to identify the axis of the residual Maximum Temperature Asymmetry (MTA) (after the dipole subtraction) of the WMAP seven-year Internal Linear Combination (ILC) cosmic microwave background temperature sky map. The estimator is based on considering the temperature differences between opposite pixels in the sky at various angular resolutions (4°-15°) and selecting the axis that maximizes this difference. We consider three large-scale HEALPix resolutions: Nside=16(3.7°), Nside=8(7.3°) and Nside=4(14.7°). We compare the direction and magnitude of this asymmetry with three other cosmic asymmetry axes (α dipole, dark energy dipole and dark flow) and find that the four asymmetry axes are abnormally close to each other. We compare the observed MTA axis with the corresponding MTA axes of 104 Gaussian isotropic simulated ILC maps (based on ΛCDM). The fraction of simulated ILC maps that reproduce the observed magnitude of the MTA asymmetry and alignment with the observed α dipole is in the range of 0.1%-0.5% (depending on the resolution chosen for the cosmic microwave background map). The corresponding magnitude+alignment probabilities with the other two asymmetry axes (dark energy dipole and dark flow) are at the level of about 1%. We propose Extended Topological Quintessence as a physical model qualitatively consistent with this coincidence of directions.

  9. Miniaturized Wilkinson Power Dividers Utilizing Capacitive Loading

    NASA Technical Reports Server (NTRS)

    Scardelletti, Maximilian C.; Ponchak, George E.; Weller, Thomas M.

    2001-01-01

    This letter reports the miniaturization of a planar Wilkinson power divider by capacitive loading of the quarter wave transmission lines employed in conventional Wilkinson power dividers. Reduction of the transmission line segments from lambda/4 to between lambda/5 and lambda/12 are reported here. The input and output lines at the three ports and the lines comprising the divider itself are coplanar waveguide (CPW) and asymmetric coplanar stripline (ACPS), respectively. The 10 GHZ power dividers are fabricated on high resistivity silicon (HRS) and alumina wafers. These miniaturized dividers are 74% smaller than conventional Wilkinson power dividers, and have a return loss better than +30 dB and an insertion loss less than 0.55 dB. Design equations and a discussion about the effect of parasitic reactance on the isolation are presented for the first time.

  10. [Dreams and interhemispheric asymmetry].

    PubMed

    Korabel'nikova, E A; Golubev, V L

    2001-01-01

    The dreams of 103 children and adolescents, aged 10-17 years, have been studied. The test group included 78 patients with neurotic disorders; control one consisted of 25 healthy subjects. Dream features, which were common for those with preferentially left asymmetry profile both in patients as well as in healthy subjects, were: less expressed novelty factor and frequent appearance of rare phenomena, such as "déjà vu in wakefulness", reality, "mixed" (overlapped) dreams, prolonged dreams in repeat sleep, frequent changes of personages and scenes of action. Left-hander dream peculiarities, being detected only in neurotic patients but not in healthy subjects, emerged as lucid phenomena deficit, "dream in dreams" and "dream reminiscence in dream" syndrome, which have been found only in left-handers. Right and left hemispheres seem to contribute in different ways to a dream formation. In authors believe that the left hemisphere seems to provide dream origin while the right hemisphere provides dream vividness, figurativeness and affective activation level. PMID:11811128

  11. Cognitive Deficits and Cerebral Asymmetry.

    ERIC Educational Resources Information Center

    Bakker, Dirk J.

    1982-01-01

    Research concerning cerebral asymmetry and its effect on scholastic achievement, reading disabilities, learning disabilities, and linguistic competence is reviewed in an exploration of brain hemisphere-specific etiologies of dyslexia. (CJ)

  12. Hemispheric Asymmetries: The Comparative View

    PubMed Central

    Ocklenburg, Sebastian; Güntürkün, Onur

    2012-01-01

    Hemispheric asymmetries play an important role in almost all cognitive functions. For more than a century, they were considered to be uniquely human but now an increasing number of findings in all vertebrate classes make it likely that we inherited our asymmetries from common ancestors. Thus, studying animal models could provide unique insights into the mechanisms of lateralization. We outline three such avenues of research by providing an overview of experiments on left–right differences in the connectivity of sensory systems, the embryonic determinants of brain asymmetries, and the genetics of lateralization. All these lines of studies could provide a wealth of insights into our own asymmetries that should and will be exploited by future analyses. PMID:22303295

  13. Social Welfare Implications of the Digital Divide

    ERIC Educational Resources Information Center

    Kim, Eunjin; Lee, Byungtae; Menon, Nirup M.

    2009-01-01

    The Internet plays a critical role in informing individuals about society, politics, business, and the environment. So much so that it has been said that the digital divide makes the segment of society on the ''right side'' of the divide (the digitally endowed group) better off and that on the ''wrong side'' (the digitally challenged group) worse…

  14. Bridge the Digital Divide for Educational Equity

    ERIC Educational Resources Information Center

    Mason, Christine Y.; Dodds, Richard

    2005-01-01

    Students' technological savvy has challenged schools to make greater use of computers and the Internet in their curricula, but unfortunately, not every student has the same access to it, and the inability to keep pace has created a digital divide that continues to widen. The digital divide particularly affects students who are black, Hispanic,…

  15. Parochial Geographies: Growing up in Divided Belfast

    ERIC Educational Resources Information Center

    Leonard, Madeleine

    2010-01-01

    This article explores the ways in which teenagers occupy and manage space in one divided community in Northern Ireland. Drawing on stories, maps and focus group discussions with 80 teenagers, from an interface area in Belfast, the article reveals their perceptions and experiences of divided cities, as risky landscapes. Teenagers respond to these…

  16. Centrosome positioning in non-dividing cells.

    PubMed

    Barker, Amy R; McIntosh, Kate V; Dawe, Helen R

    2016-07-01

    Centrioles and centrosomes are found in almost all eukaryotic cells, where they are important for organising the microtubule cytoskeleton in both dividing and non-dividing cells. The spatial location of centrioles and centrosomes is tightly controlled and, in non-dividing cells, plays an important part in cell migration, ciliogenesis and immune cell functions. Here, we examine some of the ways that centrosomes are connected to other organelles and how this impacts on cilium formation, cell migration and immune cell function in metazoan cells. PMID:26319517

  17. Cellular resilience.

    PubMed

    Smirnova, Lena; Harris, Georgina; Leist, Marcel; Hartung, Thomas

    2015-01-01

    Cellular resilience describes the ability of a cell to cope with environmental changes such as toxicant exposure. If cellular metabolism does not collapse directly after the hit or end in programmed cell death, the ensuing stress responses promote a new homeostasis under stress. The processes of reverting "back to normal" and reversal of apoptosis ("anastasis") have been studied little at the cellular level. Cell types show astonishingly similar vulnerability to most toxicants, except for those that require a very specific target, metabolism or mechanism present only in specific cell types. The majority of chemicals triggers "general cytotoxicity" in any cell at similar concentrations. We hypothesize that cells differ less in their vulnerability to a given toxicant than in their resilience (coping with the "hit"). In many cases, cells do not return to the naive state after a toxic insult. The phenomena of "pre-conditioning", "tolerance" and "hormesis" describe this for low-dose exposures to toxicants that render the cell more resistant to subsequent hits. The defense and resilience programs include epigenetic changes that leave a "memory/scar" - an alteration as a consequence of the stress the cell has experienced. These memories might have long-term consequences, both positive (resistance) and negative, that contribute to chronic and delayed manifestations of hazard and, ultimately, disease. This article calls for more systematic analyses of how cells cope with toxic perturbations in the long-term after stressor withdrawal. A technical prerequisite for these are stable (organotypic) cultures and a characterization of stress response molecular networks. PMID:26536287

  18. Expected dipole asymmetry in CMB polarization

    NASA Astrophysics Data System (ADS)

    Namjoo, M. H.; Abolhasani, A. A.; Assadullahi, H.; Baghram, S.; Firouzjahi, H.; Wands, D.

    2015-05-01

    We explore the hemispherical asymmetry predicted in cosmic microwave background polarization when there is an asymmetry in temperature anisotropies due to primordial perturbations. We consider the cases of asymmetries due to adiabatic and isocurvature modes, and tensor perturbations. We show that the asymmetry in the TE, EE and/or BB correlations can be substantially larger than those in the TT power spectrum in certain cases. The relative asymmetry in the different cross-correlations, as well as the angular scale dependence, can in principle distinguish between different origins for the asymmetry.

  19. A single dividing cell population with imbalanced fate drives oesophageal tumour growth.

    PubMed

    Frede, Julia; Greulich, Philip; Nagy, Tibor; Simons, Benjamin D; Jones, Philip H

    2016-09-01

    Understanding the cellular mechanisms of tumour growth is key for designing rational anticancer treatment. Here we used genetic lineage tracing to quantify cell behaviour during neoplastic transformation in a model of oesophageal carcinogenesis. We found that cell behaviour was convergent across premalignant tumours, which contained a single proliferating cell population. The rate of cell division was not significantly different in the lesions and the surrounding epithelium. However, dividing tumour cells had a uniform, small bias in cell fate so that, on average, slightly more dividing than non-dividing daughter cells were generated at each round of cell division. In invasive cancers induced by Kras(G12D) expression, dividing cell fate became more strongly biased towards producing dividing over non-dividing cells in a subset of clones. These observations argue that agents that restore the balance of cell fate may prove effective in checking tumour growth, whereas those targeting cycling cells may show little selectivity. PMID:27548914

  20. Sivers Asymmetry with QCD Evolution

    NASA Astrophysics Data System (ADS)

    Echevarria, Miguel G.; Idilbi, Ahmad; Kang, Zhong-Bo; Vitev, Ivan

    2015-02-01

    We analyze the Sivers asymmetry in both Drell-Yan (DY) production and semi-inclusive deep inelastic scattering (SIDIS), while considering properly defined transverse momentum dependent parton distribution and fragmentation functions and their QCD evolution. After finding a universal non-perturbative spin-independent Sudakov factor that can describe reasonably well the world's data of SIDIS, DY lepton pair and W/Z production in unpolarized scatterings, we perform a global fitting of all the experimental data on the Sivers asymmetry in SIDIS from HERMES, COMPASS and Jefferson Lab. Then we make predictions for the asymmetry in DY lepton pair and W boson production, which could be compared to the future experimental data in order to test the sign change of the Sivers function.

  1. Geometric asymmetry driven Janus micromotors.

    PubMed

    Zhao, Guanjia; Pumera, Martin

    2014-10-01

    The production and application of nano-/micromotors is of great importance. In order for the motors to work, asymmetry in their chemical composition or physical geometry must be present if no external asymmetric field is applied. In this paper, we present a "coconut" micromotor made of platinum through the partial or complete etching of the silica templates. It was shown that although both the inner and outer surfaces are made of the same material (Pt), motion of the structure can be observed as the convex surface is capable of generating oxygen bubbles. This finding shows that not only the chemical asymmetry of the micromotor, but also its geometric asymmetry can lead to fast propulsion of the motor. Moreover, a considerably higher velocity can be seen for partially etched coconut structures than the velocities of Janus or fully etched, shell-like motors. These findings will have great importance on the design of future micromotors. PMID:25122607

  2. Information asymmetry and deception

    PubMed Central

    Clots-Figueras, Irma; Hernán-González, Roberto; Kujal, Praveen

    2015-01-01

    Situations such as an entrepreneur overstating a project's value, or a superior choosing to under or overstate the gains from a project to a subordinate are common and may result in acts of deception. In this paper we modify the standard investment game in the economics literature to study the nature of deception. In this game a trustor (investor) can send a given amount of money to a trustee (or investee). The amount received is multiplied by a certain amount, k, and the investee then decides on how to divide the total amount received. In our modified game the information on the multiplier, k, is known only to the investee and she can send a non-binding message to the investor regarding its value. We find that 66% of the investees send false messages with both under and over, statement being observed. Investors are naive and almost half of them believe the message received. We find greater lying when the distribution of the multiplier is unknown by the investors than when they know the distribution. Further, messages make beliefs about the multiplier more pessimistic when the investors know the distribution of the multiplier, while the opposite is true when they do not know the distribution. PMID:26257615

  3. Information asymmetry and deception.

    PubMed

    Clots-Figueras, Irma; Hernán-González, Roberto; Kujal, Praveen

    2015-01-01

    Situations such as an entrepreneur overstating a project's value, or a superior choosing to under or overstate the gains from a project to a subordinate are common and may result in acts of deception. In this paper we modify the standard investment game in the economics literature to study the nature of deception. In this game a trustor (investor) can send a given amount of money to a trustee (or investee). The amount received is multiplied by a certain amount, k, and the investee then decides on how to divide the total amount received. In our modified game the information on the multiplier, k, is known only to the investee and she can send a non-binding message to the investor regarding its value. We find that 66% of the investees send false messages with both under and over, statement being observed. Investors are naive and almost half of them believe the message received. We find greater lying when the distribution of the multiplier is unknown by the investors than when they know the distribution. Further, messages make beliefs about the multiplier more pessimistic when the investors know the distribution of the multiplier, while the opposite is true when they do not know the distribution. PMID:26257615

  4. Temporal dynamics of divided spatial attention.

    PubMed

    Itthipuripat, Sirawaj; Garcia, Javier O; Serences, John T

    2013-05-01

    In naturalistic settings, observers often have to monitor multiple objects dispersed throughout the visual scene. However, the degree to which spatial attention can be divided across spatially noncontiguous objects has long been debated, particularly when those objects are in close proximity. Moreover, the temporal dynamics of divided attention are unclear: is the process of dividing spatial attention gradual and continuous, or does it onset in a discrete manner? To address these issues, we recorded steady-state visual evoked potentials (SSVEPs) as subjects covertly monitored two flickering targets while ignoring an intervening distractor that flickered at a different frequency. All three stimuli were clustered within either the lower left or the lower right quadrant, and our dependent measure was SSVEP power at the target and distractor frequencies measured over time. In two experiments, we observed a temporally discrete increase in power for target- vs. distractor-evoked SSVEPs extending from ∼350 to 150 ms prior to correct (but not incorrect) responses. The divergence in SSVEP power immediately prior to a correct response suggests that spatial attention can be divided across noncontiguous locations, even when the targets are closely spaced within a single quadrant. In addition, the division of spatial attention appears to be relatively discrete, as opposed to slow and continuous. Finally, the predictive relationship between SSVEP power and behavior demonstrates that these neurophysiological measures of divided attention are meaningfully related to cognitive function. PMID:23390315

  5. Temporal dynamics of divided spatial attention

    PubMed Central

    Garcia, Javier O.; Serences, John T.

    2013-01-01

    In naturalistic settings, observers often have to monitor multiple objects dispersed throughout the visual scene. However, the degree to which spatial attention can be divided across spatially noncontiguous objects has long been debated, particularly when those objects are in close proximity. Moreover, the temporal dynamics of divided attention are unclear: is the process of dividing spatial attention gradual and continuous, or does it onset in a discrete manner? To address these issues, we recorded steady-state visual evoked potentials (SSVEPs) as subjects covertly monitored two flickering targets while ignoring an intervening distractor that flickered at a different frequency. All three stimuli were clustered within either the lower left or the lower right quadrant, and our dependent measure was SSVEP power at the target and distractor frequencies measured over time. In two experiments, we observed a temporally discrete increase in power for target- vs. distractor-evoked SSVEPs extending from ∼350 to 150 ms prior to correct (but not incorrect) responses. The divergence in SSVEP power immediately prior to a correct response suggests that spatial attention can be divided across noncontiguous locations, even when the targets are closely spaced within a single quadrant. In addition, the division of spatial attention appears to be relatively discrete, as opposed to slow and continuous. Finally, the predictive relationship between SSVEP power and behavior demonstrates that these neurophysiological measures of divided attention are meaningfully related to cognitive function. PMID:23390315

  6. Chemical divides and evaporite assemblages on Mars

    NASA Astrophysics Data System (ADS)

    Tosca, Nicholas J.; McLennan, Scott M.

    2006-01-01

    Assemblages of evaporite minerals record detailed physical and chemical characteristics of ancient surficial environments. Accordingly, newly discovered regions of saline minerals on Mars are high priority targets for exploration. The chemical divide concept of evaporite mineral formation is used successfully to predict evaporite mineralogy and brine evolution on Earth. However, basaltic weathering largely controls fluid compositions on Mars and the robust predictive capabilities of terrestrial chemical divides cannot be used to interpret Martian evaporites. Here we present a new chemical divide system that predicts evaporite assemblages identified in SNC-type meteorites, ancient evaporites discovered on Meridiani Planum by the Opportunity rover, and Mars Express OMEGA data. We suggest that a common fluid type that has been buffered to different pH levels by basaltic weathering controls the variability among Martian evaporite assemblages and that evaporite mineralogy and brine evolution is essentially established by the initial composition of the dilute evaporating fluid.

  7. Radial/axial power divider/combiner

    NASA Technical Reports Server (NTRS)

    Vaddiparty, Yerriah P. (Inventor)

    1987-01-01

    An electromagnetic power divider/combiner comprises N radial outputs (31) having equal powers and preferably equal phases, and a single axial output (20). A divider structure (1) and a preferably identical combiner structure (2) are broadside coupled across a dielectric substrate (30) containing on one side the network of N radial outputs (31) and on its other side a set of N equispaced stubs (42) which are capacitively coupled through the dielectric substrate (30) to the N radial outputs (31). The divider structure (1) and the combiner structure (2) each comprise a dielectric disk (12, 22, respectively) on which is mounted a set of N radial impedance transformers (14, 24, respectively). Gross axial coupling is determined by the thickness of the dielectric layer (30). Rotating the disks (12, 22) with respect to each other effectuates fine adjustment in the degree of axial coupling.

  8. Wideband unbalanced waveguide power dividers and combiners

    DOEpatents

    Halligan, Matthew; McDonald, Jacob Jeremiah; Strassner, II, Bernd H.

    2016-05-17

    The various technologies presented herein relate to waveguide dividers and waveguide combiners for application in radar systems, wireless communications, etc. Waveguide dividers-combiners can be manufactured in accordance with custom dimensions, as well as in accordance with waveguide standards such that the input and output ports are of a defined dimension and have a common impedance. Various embodiments are presented which can incorporate one or more septum(s), one or more pairs of septums, an iris, an input matching region, a notch located on the input waveguide arm, waveguide arms having stepped transformer regions, etc. The various divider configurations presented herein can be utilized in high fractional bandwidth applications, e.g., a fractional bandwidth of about 30%, and RF applications in the Ka frequency band (e.g., 26.5-40 GHz).

  9. Hemispheric Asymmetries and Cognitive Attributes.

    ERIC Educational Resources Information Center

    Federico, Pat-Anthony

    Visual, auditory, and bimodal event-related potentials were recorded from 50 males, and lateral asymmetry indices were derived. Eleven psychometric tests of different cognitive attributes were also administered to them. This area of research has been labeled aptitude-treatment-interaction (ATI). The emphasis of ATI research is on identification of…

  10. A Global Gait Asymmetry Index.

    PubMed

    Cabral, Silvia; Resende, Renan A; Clansey, Adam C; Deluzio, Kevin J; Selbie, W Scott; Veloso, António P

    2016-04-01

    High levels of gait asymmetry are associated with many pathologies. Our long-term goal is to improve gait symmetry through real-time biofeedback of a symmetry index. Symmetry is often reported as a single metric or a collective signature of multiple discrete measures. While this is useful for assessment, incorporating multiple feedback metrics presents too much information for most subjects to use as visual feedback for gait retraining. The aim of this article was to develop a global gait asymmetry (GGA) score that could be used as a biofeedback metric for gait retraining and to test the effectiveness of the GGA for classifying artificially-induced asymmetry. Eighteen participants (11 males; age 26.9 y [SD = 7.7]; height 1.8 m [SD = 0.1]; body mass 72.7 kg [SD = 8.9]) walked on a treadmill in 3 symmetry conditions, induced by wearing custom-made sandals: a symmetric condition (identical sandals) and 2 asymmetric conditions (different sandals). The GGA score was calculated, based on several joint angles, and compared between conditions. Significant differences were found among all conditions (P < .001), meaning that the GGA score is sensitive to different levels of asymmetry, and may be useful for rehabilitation and assessment. PMID:26502455

  11. CAF-1-Mediated Chromatin Assembly Generates a Bilateral Asymmetry in C. elegans Neuroanatomy

    PubMed Central

    Nakano, Shunji; Stillman, Bruce; Horvitz, H. Robert

    2012-01-01

    Summary Chromatin assembly is a fundamental cellular process, but its role during animal development remains largely elusive. Here we report that the CAF-1 protein complex, an evolutionarily conserved histone chaperone that deposits histone H3-H4 proteins onto replicating DNA, is required to generate a bilateral asymmetry in the C. elegans nervous system. We describe our findings that a mutation in one of 24 C. elegans histone H3 genes specifically eliminates this aspect of neuronal asymmetry. This histone H3 mutation causes a defect in the formation of a histone H3-H4 tetramer and the consequent inhibition of CAF-1-mediated nucleosome formation. Our results reveal that replication-coupled nucleosome assembly is necessary to generate a bilateral asymmetry in C. elegans neuroanatomy and suggest that left-right asymmetric epigenetic regulation can establish bilateral asymmetry in the nervous system. PMID:22177093

  12. WIDE BAND REGENERATIVE FREQUENCY DIVIDER AND MULTIPLIER

    DOEpatents

    Laine, E.F.

    1959-11-17

    A regenerative frequency divider and multiplier having wide band input characteristics is presented. The circuit produces output oscillations having frequencies related by a fixed ratio to input oscillations over a wide band of frequencies. In accomplishing this end, the divider-multiplier includes a wide band input circuit coupled by mixer means to a wide band output circuit having a pass band related by a fixed ratio to that of the input circuit. A regenerative feedback circuit derives a fixed frequency ratio feedback signal from the output circuit and applies same to the mixer means in proper phase relation to sustain fixed frequency ratio oscillations in the output circuit.

  13. Microstrip amplitude-weighted wilkinson power dividers

    NASA Astrophysics Data System (ADS)

    Huck, K. D.

    1986-03-01

    Unequal-split reactive power dividers were examined for use in forming amplitude tapers for microstrip array antennas. Circuits with power ratios of up to 5.0 between arms were constructed on Rexolite substrate, for operation at 4.0 GHz and 7.5 GHz. The 4.0 GHz circuits were very accurate in forming the correct amplitude ratio between outputs, and in maintaining phase balance between outputs. Of those circuits designed for 7.5 GHz, only those with split ratios less than 2.5 worked correctly. This report includes a review of the theory, measured results, and recommendations for improved power dividers.

  14. Focused and divided attention in Alzheimer's disease.

    PubMed

    Nebes, R D; Brady, C B

    1989-06-01

    Visual search tasks were used to examine two aspects of selective attention (focused and divided attention) in normal young and older persons and in Alzheimer patients. Normal and demented subjects were equally efficient in using a color cue to selectively search only the relevant items in an array. Thus, focused attention abilities appear to be relatively unimpaired by Alzheimer's disease. By contrast, in comparison to normals, the search time of demented patients rose disproportionately as the number of items over which they had to distribute their attention was increased. This suggests that Alzheimer patients are less efficient than normals in dividing their attention. PMID:2758855

  15. From symmetry to asymmetry: Phylogenetic patterns of asymmetry variation in animals and their evolutionary significance

    PubMed Central

    Palmer, A. Richard

    1996-01-01

    Phylogenetic analyses of asymmetry variation offer a powerful tool for exploring the interplay between ontogeny and evolution because (i) conspicuous asymmetries exist in many higher metazoans with widely varying modes of development, (ii) patterns of bilateral variation within species may identify genetically and environmentally triggered asymmetries, and (iii) asymmetries arising at different times during development may be more sensitive to internal cytoplasmic inhomogeneities compared to external environmental stimuli. Using four broadly comparable asymmetry states (symmetry, antisymmetry, dextral, and sinistral), and two stages at which asymmetry appears developmentally (larval and postlarval), I evaluated relations between ontogenetic and phylogenetic patterns of asymmetry variation. Among 140 inferred phylogenetic transitions between asymmetry states, recorded from 11 classes in five phyla, directional asymmetry (dextral or sinistral) evolved directly from symmetrical ancestors proportionally more frequently among larval asymmetries. In contrast, antisymmetry, either as an end state or as a transitional stage preceding directional asymmetry, was confined primarily to postlarval asymmetries. The ontogenetic origin of asymmetry thus significantly influences its subsequent evolution. Furthermore, because antisymmetry typically signals an environmentally triggered asymmetry, the phylogenetic transition from antisymmetry to directional asymmetry suggests that many cases of laterally fixed asymmetries evolved via genetic assimilation. PMID:8962039

  16. Micropatterned mammalian cells exhibit phenotype-specific left-right asymmetry

    PubMed Central

    Wan, Leo Q.; Ronaldson, Kacey; Park, Miri; Taylor, Grace; Zhang, Yue; Gimble, Jeffrey M.; Vunjak-Novakovic, Gordana

    2011-01-01

    Left-right (LR) asymmetry (handedness, chirality) is a well-conserved biological property of critical importance to normal development. Changes in orientation of the LR axis due to genetic or environmental factors can lead to malformations and disease. While the LR asymmetry of organs and whole organisms has been extensively studied, little is known about the LR asymmetry at cellular and multicellular levels. Here we show that the cultivation of cell populations on micropatterns with defined boundaries reveals intrinsic cell chirality that can be readily determined by image analysis of cell alignment and directional motion. By patterning 11 different types of cells on ring-shaped micropatterns of various sizes, we found that each cell type exhibited definite LR asymmetry (p value down to 10-185) that was different between normal and cancer cells of the same type, and not dependent on surface chemistry, protein coating, or the orientation of the gravitational field. Interestingly, drugs interfering with actin but not microtubule function reversed the LR asymmetry in some cell types. Our results show that micropatterned cell populations exhibit phenotype-specific LR asymmetry that is dependent on the functionality of the actin cytoskeleton. We propose that micropatterning could potentially be used as an effective in vitro tool to study the initiation of LR asymmetry in cell populations, to diagnose disease, and to study factors involved with birth defects in laterality. PMID:21709270

  17. W asymmetries at CDF and D0

    SciTech Connect

    Schellman, H.

    2010-08-01

    We present recent W and charged lepton asymmetry measurements from the CDF and D0 experiments. Theoretical predictions agree with the CDF W asymmetry, measured using a new matrix element technique. These theoretical predictions are less consistent with the latest lepton asymmetry measurements from D0 and CDF, especially for high charged lepton transverse momentum.

  18. From Digital Divide to Digital Democracy.

    ERIC Educational Resources Information Center

    de los Santos, Gerardo E., Ed.; de los Santos, Alfredo G., Jr., Ed.; Milliron, Mark David, Ed.

    This publication is one of many efforts of the League for Innovation in the Community College to address the issue of societal technology access and learning needs. This work addresses the issue of the digital divide, which includes the often conflicting perspectives of information technology (IT) access and literacy needs held by government…

  19. THE DEVELOPMENT OF THE TEACHING SPACE DIVIDER.

    ERIC Educational Resources Information Center

    BELLOMY, CLEON C.; CAUDILL, WILLIAM W.

    TYPES OF VERTICAL WORK SURFACES AND THE DEVELOPMENT OF A MODEL TEACHING SPACE DIVIDER ARE DISCUSSED IN THIS REPORT. THIS DESIGN IS BASED ON THE EXPRESSED NEED FOR MORE TACKBOARD AND SHELVING SPACE, AND FOR MOVABLE PARTITIONS. THE MODEL PANELS WHICH SERVE DIRECTLY AS PARTITIONS RATHER THAN BEING OVERLAID ON A PLASTERED SURFACE, INCLUDE THE…

  20. A Nation Divided on Education in 2003

    ERIC Educational Resources Information Center

    Hardy, Lawrence

    2004-01-01

    To understand what is going on in American education, it might help to turn to a relatively neutral source, the Pew Research Center for the People and the Press, and its released report, The 2004 Political Landscape: Evenly Divided and Increasingly Polarized. "Over the past four years, the American electorate has been dealt a series of body blows,…

  1. Crossing Divides: The Legacy of Graham Nuthall

    ERIC Educational Resources Information Center

    Davis, Alan

    2006-01-01

    Graham Nuthall's work cuts across methodological and conceptual divides that have worked against the development of a theory of learning and teaching that is at once predictive and practical. The micro-genetic approach to research on learning in classrooms that he developed with Adrienne Alton-Lee successfully transcends the unhelpful dichotomy…

  2. Young People's Internet Use: Divided or Diversified?

    ERIC Educational Resources Information Center

    Boonaert, Tom; Vettenburg, Nicole

    2011-01-01

    This article critically analyses research on young people's internet use. Based on a literature analysis, it examines which young people do what on the internet. These results invite a reflection on the dominant discourse on the digital divide. Within this discourse, there is a strong focus on the use of the internet for information purposes only,…

  3. Bridging the Digital Divide in Higher Education.

    ERIC Educational Resources Information Center

    Treviranus, Jutta; Coombs, Norman

    The emergence of the digital campus, and the rapid convergence of previously disparate methods of communicating information, presents both a risk and an opportunity for people with disabilities. The imminent risk is that non-inclusive design of the digital campus will irreparably widen the digital divide within higher education, to the detriment…

  4. An automatic bridge for inductive voltage dividers

    SciTech Connect

    Chang, P.; Liang, C.P.; Hsiao, J.C.

    1994-12-31

    We describe an automatic, injection-type bridge for inductive voltage divider (IVD) applications at low audio frequencies. We used it to self-calibrate programmable IVDs fabricated in house, by an automated {open_quotes}boot-strap{close_quotes} procedure. It is the heart of our reference standard for ac voltage ratios as well as a calibration system for IVDs.

  5. Cybercounseling and Empowerment: Bridging the Digital Divide.

    ERIC Educational Resources Information Center

    Lee, Courtland C.

    As helping professions enter the 21st century and nascent network technologies realize their full potential as therapeutic and educational modalities, it is an ethical and moral imperative that the digital divide be bridged. It is important that those in counseling and related fields take active steps to ensure that cybercounseling is available to…

  6. Leveraging Resources to Close the Divide

    ERIC Educational Resources Information Center

    Rourke, James R.

    2007-01-01

    A host of real and perceived chasms divide students who achieve high academic standards and those who fail to meet them: varying expectations, economic status, resources, cultural and racial preconceptions, inappropriate standards, and so on. Yet as with all human endeavors throughout history, inventors, innovators, and risk takers rise to the…

  7. Divide and Multiply: Baptist Diversity in Appalachia.

    ERIC Educational Resources Information Center

    Dorgan, Howard

    1996-01-01

    Baptists' propensity for splitting apart arises from the faith's avowed love of theological argument. Gives an overview of Baptist denominations, and identifies the main issues that divide them: atonement, predestination, the nature and origins of good and evil, worship practices, church governance, gender issues, and other social and cultural…

  8. Project DIVIDE Instrument Development. Technical Report # 0810

    ERIC Educational Resources Information Center

    Ketterlin-Geller, Leanne; Jung, Eunju; Geller, Josh; Yovanoff, Paul

    2008-01-01

    In this technical report, we describe the development of cognitive diagnostic test items that form the basis of the diagnostic system for Project DIVIDE (Dynamic Instruction Via Individually Designed Environments). The construct underlying the diagnostic test is division of fractions. We include a description of the process we used to identify the…

  9. Geometric asymmetry driven Janus micromotors

    NASA Astrophysics Data System (ADS)

    Zhao, Guanjia; Pumera, Martin

    2014-09-01

    The production and application of nano-/micromotors is of great importance. In order for the motors to work, asymmetry in their chemical composition or physical geometry must be present if no external asymmetric field is applied. In this paper, we present a ``coconut'' micromotor made of platinum through the partial or complete etching of the silica templates. It was shown that although both the inner and outer surfaces are made of the same material (Pt), motion of the structure can be observed as the convex surface is capable of generating oxygen bubbles. This finding shows that not only the chemical asymmetry of the micromotor, but also its geometric asymmetry can lead to fast propulsion of the motor. Moreover, a considerably higher velocity can be seen for partially etched coconut structures than the velocities of Janus or fully etched, shell-like motors. These findings will have great importance on the design of future micromotors.The production and application of nano-/micromotors is of great importance. In order for the motors to work, asymmetry in their chemical composition or physical geometry must be present if no external asymmetric field is applied. In this paper, we present a ``coconut'' micromotor made of platinum through the partial or complete etching of the silica templates. It was shown that although both the inner and outer surfaces are made of the same material (Pt), motion of the structure can be observed as the convex surface is capable of generating oxygen bubbles. This finding shows that not only the chemical asymmetry of the micromotor, but also its geometric asymmetry can lead to fast propulsion of the motor. Moreover, a considerably higher velocity can be seen for partially etched coconut structures than the velocities of Janus or fully etched, shell-like motors. These findings will have great importance on the design of future micromotors. Electronic supplementary information (ESI) available: Additional SEM images, data analysis, Videos S

  10. Systematic Mapping and Statistical Analyses of Valley Landform and Vegetation Asymmetries Across Hydroclimatic Gradients

    NASA Astrophysics Data System (ADS)

    Poulos, M. J.; Pierce, J. L.; McNamara, J. P.; Flores, A. N.; Benner, S. G.

    2015-12-01

    Terrain aspect alters the spatial distribution of insolation across topography, driving eco-pedo-hydro-geomorphic feedbacks that can alter landform evolution and result in valley asymmetries for a suite of land surface characteristics (e.g. slope length and steepness, vegetation, soil properties, and drainage development). Asymmetric valleys serve as natural laboratories for studying how landscapes respond to climate perturbation. In the semi-arid montane granodioritic terrain of the Idaho batholith, Northern Rocky Mountains, USA, prior works indicate that reduced insolation on northern (pole-facing) aspects prolongs snow pack persistence, and is associated with thicker, finer-grained soils, that retain more water, prolong the growing season, support coniferous forest rather than sagebrush steppe ecosystems, stabilize slopes at steeper angles, and produce sparser drainage networks. We hypothesize that the primary drivers of valley asymmetry development are changes in the pedon-scale water-balance that coalesce to alter catchment-scale runoff and drainage development, and ultimately cause the divide between north and south-facing land surfaces to migrate northward. We explore this conceptual framework by coupling land surface analyses with statistical modeling to assess relationships and the relative importance of land surface characteristics. Throughout the Idaho batholith, we systematically mapped and tabulated various statistical measures of landforms, land cover, and hydroclimate within discrete valley segments (n=~10,000). We developed a random forest based statistical model to predict valley slope asymmetry based upon numerous measures (n>300) of landscape asymmetries. Preliminary results suggest that drainages are tightly coupled with hillslopes throughout the region, with drainage-network slope being one of the strongest predictors of land-surface-averaged slope asymmetry. When slope-related statistics are excluded, due to possible autocorrelation, valley

  11. Splicing the Divide: A Review of Research on the Evolving Digital Divide among K-12 Students

    ERIC Educational Resources Information Center

    Dolan, Jennifer E.

    2016-01-01

    The digital divide has narrowed with regard to one definition of access to technology--the binary view of the "haves" and "have-nots." However, use of technology at home and in school is not equitable for all students. According to recent literature, a broader and more nuanced definition of the technological divide is necessary…

  12. Low phase noise digital frequency divider

    NASA Technical Reports Server (NTRS)

    Lutes, G. F., Jr. (Inventor)

    1973-01-01

    A low phase noise frequency divider composed of a grating arrangement is disclosed. The grating arrangement supplies selected portions of an input reference signal to be divided to a tuned circuit without any phase noise due to the grating action. The arrangement which in one embodiment consists of an FET is connected to the tuned circuit input to short out the input except when the input reference signal amplitude crosses ground level in a positive direction and a gate enabling signal is present at the gate electrode of the FET. The gate enabling signal alone does not decouple the tuned circuit input from ground, therefore phase noise, due to the leading and trailing edges of each gate-enabling signal, is substantially eliminated.

  13. Divided or kissing nevus of the penis.

    PubMed

    Hardin, Carolyn A; Tieu, Kathy D

    2013-10-01

    The divided or kissing nevus is an unusual congenital melanocytic nevus. By definition, these nevi appear on skin that separates during embryological development. These lesions have been reported on the eyelids, fingers, and rarely the penis. We describe an 18 year old uncircumcised male who presented with an asymptomatic darkly pigmented patch on the glans penis. He reported that the lesion had appeared recently and was enlarging. Physical examination revealed a second symmetric lesion on the adjacent foreskin. Punch biopsy of the lesion on the glans penis showed abundant intradermal melanocytes devoid of mitoses and atypia, consistent with an intradermal melanocytic nevus. Based on the benign histologic nature and clinical exam, the lesion was diagnosed as a divided or kissing nevus of the penis. Proposed treatments include excision and grafting as well as Nd:YAG laser therapy. However, these patients may be safely monitored with regular follow-up skin examinations because there is minimal risk of malignant transformation. PMID:24139368

  14. Motor Asymmetry in Elite Fencers

    PubMed Central

    Akpinar, Selcuk; Sainburg, Robert L.; Kirazci, Sadettin; Przybyla, Andrzej

    2014-01-01

    We previously reported that asymmetrical patterns of hand preference are updated and modified by current sensorimotor conditions. We now examine whether participation in long-term training in the upper extremity sport fencing might modify arm selection and performance asymmetries. Eight fencers and eight non-fencers performed reaching movements under three experimental conditions: (1) non-choice right; (2) non-choice left; and (3) choice, either right or left arm as selected by subject. The non-choice conditions allowed assessment of potential interlimb differences in movement performance, while the choice condition allowed assessment of the frequency and pattern of arm selection across subject groups. Our findings showed that the athlete groups showed substantially greater symmetry in both our performance and selection measures. These findings suggest that arm selection and performance asymmetries can be altered by intense long-term practice. PMID:25494618

  15. Can Attention be Divided Between Perceptual Groups?

    NASA Technical Reports Server (NTRS)

    McCann, Robert S.; Foyle, David C.; Johnston, James C.; Hart, Sandra G. (Technical Monitor)

    1994-01-01

    Previous work using Head-Up Displays (HUDs) suggests that the visual system parses the HUD and the outside world into distinct perceptual groups, with attention deployed sequentially to first one group and then the other. New experiments show that both groups can be processed in parallel in a divided attention search task, even though subjects have just processed a stimulus in one perceptual group or the other. Implications for models of visual attention will be discussed.

  16. Lake Buchannan, Great Dividing Range, Queensland, Australia

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Lake Buchannan, a small but blue and prominent in the center of the view, lies in the Great Dividing of Queensland, Australia (22.0S, 146.0E). The mountain range in this case is a low plateau of no more than 2,000 to 3,000 ft altitude. The interior is dry, mostly in pasture but the coastal zone in contrast, is wet tropical country where bananas and sugarcane are grown.

  17. Will the Nicaragua Canal connect or divide?

    PubMed

    Gross, Michael

    2014-11-01

    A century after the opening of the Panama Canal, a second inter-oceanic passage is set to be built in Central America, this time in Nicaragua. The ambitious and astronomically expensive project promises to bring economic opportunity to a poor country but it also carries risks to its tropical ecosystems. Will the new waterway ultimately link two oceans or divide a continent? Michael Gross investigates. PMID:25587585

  18. Relationship between the fraction of backscattered light and the asymmetry parameter

    NASA Astrophysics Data System (ADS)

    Horvath, Helmuth

    2015-04-01

    The fraction of backscattered light is defined as the ratio of the integral of the volume scattering function over the backward half solid angle divided by the integral of the volume scattering function over the full solid angle. It can be measured with an integrating nephelometer. On the other hand the asymmetry parameter is the integral over the full solid angle of the volume scattering function weighted with the cosine of the scattering angle divided by the integral of the volume scattering function. To determine the asymmetry parameter the measurement of the angular dependence of the volume scattering function is needed, which can be obtained e.g. with a polar nephelometer. The asymmetry parameter is an important input parameter for radiative transfer calculations in order to obtain information of effects of the atmospheric aerosol effects (climate, screening, visibility, and others). Unfortunately measurements of the asymmetry parameter of the atmospheric aerosol are scarce. It is obvious, that a relation between the asymmetry parameter and the backscattered fraction should exist: the smaller the backscattered fraction, the more asymmetric the scattering, thus the larger the asymmetry parameter. A large set of 6500 angular scattering data have been obtained at various locations of the world: Vienna (Austria), Kyoto (Japan), Granada (Spain) and Palencia (Spain). The aerosols in these locations were considerably different, ranging from continental, urban, maritime, to desert dust. The volume scattering function has been measured between 5° and 175° , the values for 0° to 5° and 175° to 180° have been obtained by extrapolation of the shape of the curve, thus the whole range of scattering angles was available for calculating the backscattered fraction and the asymmetry parameter of the aerosol. PIC A summary of all data is shown in figure 1. The majority of the data points suggest an unanimous relation between backscattering and asymmetry parameter. The

  19. Cardiolipin asymmetry, oxidation and signaling

    PubMed Central

    Kagan, Valerian E.; Chu, Charleen T.; Tyurina, Yulia Y.; Cheikhi, Amin; Bayir, Hülya

    2014-01-01

    Cardiolipins (CLs) are ancient and unusual dimeric phospholipids localized in the plasma membrane of bacteria and in the inner mitochondrial membrane of eukaryotes. In mitochondria, two types of asymmetries – trans-membrane and molecular - are essential determinants of CL functions. In this review, we describe CL-based signaling mitochondrial pathways realized via modulation of trans-membrane asymmetry and leading to externalization and peroxidation of CLs in mitophagy and apoptosis, respectively. We discuss possible mechanisms of CL translocations from the inner leaflet of the inner to the outer leaflet of the outer mitochondrial membranes. We present redox reaction mechanisms of cytochrome c-catalyzed CL peroxidation as a required stage in the execution of apoptosis as well as a possible source of lipid mediators. We also emphasize the significance of CL-related metabolic pathways as new targets for drug discovery. Finally, a remarkable diversity of polyunsaturated CL species and their oxidation products have evolved in eukaryotes vs. prokaryotes. This diversity - associated with CL molecular asymmetry - is presented as the basis for mitochondrial communications language. PMID:24300280

  20. Lean Mass Asymmetry Influences Force and Power Asymmetry During Jumping in Collegiate Athletes

    PubMed Central

    Bell, David R.; Sanfilippo, Jennifer L.; Binkley, Neil; Heiderscheit, Bryan C.

    2015-01-01

    The purpose of this investigation was to: (1) examine how asymmetry in lower extremity lean mass influenced force and power asymmetry during jumping, (2) determine how power and force asymmetry affected jump height, and (3) report normative values in collegiate athletes. Force and power were assessed from each limb using bilateral force plates during a countermovement jump in 167 Division 1 athletes (mass=85.7±20.3kg, age=20.0±1.2years, 103M/64F). Lean mass of the pelvis, thigh, and shank was assessed via dual-energy X-ray absorptiometry. Percent asymmetry was calculated for lean mass at each region (pelvis, thigh, and shank) as well as force and power. Forward stepwise regressions were performed to determine the influence of lean mass asymmetry on force and power asymmetry. Thigh and shank lean mass asymmetry explained 20% of the variance in force asymmetry (R2=0.20, P<0.001), while lean mass asymmetry of the pelvis, thigh and shank explained 25% of the variance in power asymmetry (R2=0.25, P<0.001). Jump height was compared across level of force and power asymmetry (P>0.05) and greater than 10% asymmetry in power tended to decrease performance (effect size>1.0). Ninety-five percent of this population (2.5th to 97.5th percentile) displayed force asymmetry between −11.8 to 16.8% and a power asymmetry between −9.9 to 11.5%. A small percentage (<4%) of these athletes displayed more than 15% asymmetry between limbs. These results demonstrate that lean mass asymmetry in the lower extremity is at least partially responsible for asymmetries in force and power. However, a large percentage remains unexplained by lean mass asymmetry. PMID:24402449

  1. Meyer's loop asymmetry and language lateralisation in epilepsy

    PubMed Central

    Nowell, Mark; Vos, Sjoerd B; Sidhu, Meneka; Wilcoxen, Kaitlin; Sargsyan, Narek; Ourselin, Sebastien; Duncan, John S

    2016-01-01

    Objectives Several studies have suggested an asymmetry in Meyer's loop in individuals, with the left loop anterior to the right. In this study we test the hypothesis that there is an association between Meyer's loop asymmetry (MLA) and language lateralisation. Methods 57 patients with epilepsy were identified with language functional MRI (fMRI) and diffusion MRI acquisition. Language lateralisation indices from fMRI(LI) and optic radiation and arcuate fasciculus probabilistic tractography was performed for each subject. The subjects were divided into left language dominant (LI>0.4) and non-left language groups (LI<0.4) according to their LI. Results A negative linear correlation was identified between language lateralisation and MLA, with greater left lateralised language associated with more anteriorly placed left Meyer's loops (R value −0.34, p=0.01). There was a significant difference in mean MLA between the two groups, with the left loop being anterior to the right loop in the LI>0.4 group and posterior to the right loop in the LI<0.4 group (p=0.003). No correlation was found between language lateralisation and arcuate fasciculus volume. Conclusions This study suggests an association between the extent of Meyer's loop asymmetry and the lateralisation of language determined by fMRI in patients with epilepsy. Further studies should be carried out to evaluate this association in control subjects and with other measures of language lateralisation. PMID:26384513

  2. A Cul-3-BTB ubiquitylation pathway regulates junctional levels and asymmetry of core planar polarity proteins

    PubMed Central

    Strutt, Helen; Searle, Elizabeth; Thomas-MacArthur, Victoria; Brookfield, Rosalind; Strutt, David

    2013-01-01

    The asymmetric localisation of core planar polarity proteins at apicolateral junctions is required to specify cell polarity in the plane of epithelia. This asymmetric distribution of the core proteins is proposed to require amplification of an initial asymmetry by feedback loops. In addition, generation of asymmetry appears to require the regulation of core protein levels, but the importance of such regulation and the underlying mechanisms is unknown. Here we show that ubiquitylation acts through more than one mechanism to control core protein levels in Drosophila, and that without this regulation cellular asymmetry is compromised. Levels of Dishevelled at junctions are regulated by a Cullin-3-Diablo/Kelch ubiquitin ligase complex, the activity of which is most likely controlled by neddylation. Furthermore, activity of the deubiquitylating enzyme Fat facets is required to maintain Flamingo levels at junctions. Notably, ubiquitylation does not alter the total cellular levels of Dishevelled or Flamingo, but only that of the junctional population. When junctional core protein levels are either increased or decreased by disruption of the ubiquitylation machinery, their asymmetric localisation is reduced and this leads to disruption of planar polarity at the tissue level. Loss of asymmetry by altered core protein levels can be explained by reference to feedback models for amplification of asymmetry. PMID:23487316

  3. Peripheral neuropathy reduces asymmetries in inter-limb transfer in a visuo-motor task.

    PubMed

    Pan, Zhujun; Van Gemmert, Arend W A

    2016-05-01

    Asymmetry of inter-limb transfer has been associated with the specialization of the dominant and non-dominant motor system. Reductions of asymmetry have been interpreted as behavioural evidence showing a decline of hemispheric lateralization. A previous study showed that ageing did not qualitatively change the inter-limb transfer asymmetry of a visuo-motor task. The current study elaborates on these findings; it examines whether diminished somatosensory information as a result of peripheral neuropathy (PN) adversely affects inter-limb transfer asymmetry. Twenty individuals affected by PN and 20 older controls were recruited and divided equally across two groups. One group trained a visuo-motor task with the right hand while the other group trained it with the left hand. Performance (initial direction error) of the untrained hand before and after training was collected to determine learning effects from inter-limb transfer. Similar to previous studies, the current study showed asymmetric inter-limb transfer in older controls. In contrast, PN showed inter-limb transfer in both directions indicating that PN reduces inter-limb transfer asymmetry. Increased bilateral hemispheric recruitment is suggested to be responsible for this reduced asymmetry which may compensate for deteriorated tactile and/or proprioceptive inputs in PN. Two possible hypotheses are discussed explaining the relationship between declined somatosensory information and increases in bilateral hemispheric recruitment. PMID:26857239

  4. Preferential solvation: dividing surface vs excess numbers.

    PubMed

    Shimizu, Seishi; Matubayasi, Nobuyuki

    2014-04-10

    How do osmolytes affect the conformation and configuration of supramolecular assembly, such as ion channel opening and actin polymerization? The key to the answer lies in the excess solvation numbers of water and osmolyte molecules; these numbers are determinable solely from experimental data, as guaranteed by the phase rule, as we show through the exact solution theory of Kirkwood and Buff (KB). The osmotic stress technique (OST), in contrast, purposes to yield alternative hydration numbers through the use of the dividing surface borrowed from the adsorption theory. However, we show (i) OST is equivalent, when it becomes exact, to the crowding effect in which the osmolyte exclusion dominates over hydration; (ii) crowding is not the universal driving force of the osmolyte effect (e.g., actin polymerization); (iii) the dividing surface for solvation is useful only for crowding, unlike in the adsorption theory which necessitates its use due to the phase rule. KB thus clarifies the true meaning and limitations of the older perspectives on preferential solvation (such as solvent binding models, crowding, and OST), and enables excess number determination without any further assumptions. PMID:24689966

  5. Dentofacial Asymmetries: Challenging Diagnosis and Treatment Planning

    PubMed Central

    Agrawal, Manish; Agrawal, Jiwan Asha; Nanjannawar, Lalita; Fulari, Sangamesh; Kagi, Vishwal

    2015-01-01

    Dentofacial asymmetry is quite common and when sufficiently severe can require surgical orthodontic intervention. Asymmetries can be classified according to the structures involved into skeletal, dental and functional. In diagnosing asymmetries, a thorough clinical examination and radiographic survey are essential to determine the extent of soft tissue, skeletal, dental and functional involvement. Dental asymmetries, as well as a variety of functional deviations, can be managed orthodontically, whereas significant structural facial asymmetries require a comprehensive orthodontic and orthognathic management. With less severe dental, skeletal and soft tissue deviations the advisability of treatment should be carefully considered. The following article also contains a case report highlighting the importance of proper diagnosis in treatment plan for management of dentofacial asymmetry. PMID:26229387

  6. Dentofacial Asymmetries: Challenging Diagnosis and Treatment Planning.

    PubMed

    Agrawal, Manish; Agrawal, Jiwan Asha; Nanjannawar, Lalita; Fulari, Sangamesh; Kagi, Vishwal

    2015-07-01

    Dentofacial asymmetry is quite common and when sufficiently severe can require surgical orthodontic intervention. Asymmetries can be classified according to the structures involved into skeletal, dental and functional. In diagnosing asymmetries, a thorough clinical examination and radiographic survey are essential to determine the extent of soft tissue, skeletal, dental and functional involvement. Dental asymmetries, as well as a variety of functional deviations, can be managed orthodontically, whereas significant structural facial asymmetries require a comprehensive orthodontic and orthognathic management. With less severe dental, skeletal and soft tissue deviations the advisability of treatment should be carefully considered. The following article also contains a case report highlighting the importance of proper diagnosis in treatment plan for management of dentofacial asymmetry. PMID:26229387

  7. WIMP abundance and lepton (flavour) asymmetry

    SciTech Connect

    Stuke, Maik; Schwarz, Dominik J.; Starkman, Glenn E-mail: dschwarz@physik.uni-bielefeld.de

    2012-03-01

    We investigate how large lepton asymmetries affect the evolution of the early universe at times before big bang nucleosynthesis and in particular how they influence the relic density of WIMP dark matter. In comparison to the standard calculation of the relic WIMP abundance we find a decrease, depending on the lepton flavour asymmetry. We find an effect of up to 20 per cent for lepton flavour asymmetries l{sub f} = O(0.1)

  8. Smallness of baryon asymmetry from split supersymmetry

    SciTech Connect

    Kasuya, Shinta; Takahashi, Fuminobu

    2005-06-15

    The smallness of the baryon asymmetry in our universe is one of the greatest mysteries and may originate from some profound physics beyond the standard model. We investigate the Affleck-Dine baryogenesis in split supersymmetry, and find that the smallness of the baryon asymmetry is directly related to the hierarchy between the supersymmetry breaking squark/slepton masses and the weak scale. Put simply, the baryon asymmetry is small because of the split mass spectrum.

  9. Gravitational asymmetries in gaseous disks.

    NASA Astrophysics Data System (ADS)

    Junqueira, S.; Combes, F.

    1997-12-01

    The authors report preliminary results of self-gravitating simulations of spiral galaxies modeled by two components, stellar and gaseous disks. One of the objectives of this work is to study asymmetries in the distribution of the gas, features observed for a number of spiral galaxies. The gas disk is simulated by the Beam-Scheme method, where the gas is considered as a fluid. The results suggest that very concentrated galactic disks can be unstable to the one-armed (m = 1) spiral perturbation, which may explain the asymmetric patterns observed in isolated galaxies.

  10. 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

  11. Jet vectoring through nozzle asymmetry

    NASA Astrophysics Data System (ADS)

    Roh, Chris; Rosakis, Alexandros; Gharib, Morteza

    2015-11-01

    Previously, we explored the functionality of a tri-leaflet anal valve of a dragonfly larva. We saw that the dragonfly larva is capable of controlling the three leaflets independently to asymmetrically open the nozzle. Such control resulted in vectoring of the jet in various directions. To further understand the effect of asymmetric nozzle orifice, we tested jet flow through circular asymmetric nozzles. We report the relationship between nozzle asymmetry and redirecting of the jet at various Reynolds numbers. This material is based upon work supported by the National Science Foundation under Grant No. CBET-1511414; additional support by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1144469.

  12. Quantum speed limits, coherence, and asymmetry

    NASA Astrophysics Data System (ADS)

    Marvian, Iman; Spekkens, Robert W.; Zanardi, Paolo

    2016-05-01

    The resource theory of asymmetry is a framework for classifying and quantifying the symmetry-breaking properties of both states and operations relative to a given symmetry. In the special case where the symmetry is the set of translations generated by a fixed observable, asymmetry can be interpreted as coherence relative to the observable eigenbasis, and the resource theory of asymmetry provides a framework to study this notion of coherence. We here show that this notion of coherence naturally arises in the context of quantum speed limits. Indeed, the very concept of speed of evolution, i.e., the inverse of the minimum time it takes the system to evolve to another (partially) distinguishable state, is a measure of asymmetry relative to the time translations generated by the system Hamiltonian. Furthermore, the celebrated Mandelstam-Tamm and Margolus-Levitin speed limits can be interpreted as upper bounds on this measure of asymmetry by functions which are themselves measures of asymmetry in the special case of pure states. Using measures of asymmetry that are not restricted to pure states, such as the Wigner-Yanase skew information, we obtain extensions of the Mandelstam-Tamm bound which are significantly tighter in the case of mixed states. We also clarify some confusions in the literature about coherence and asymmetry, and show that measures of coherence are a proper subset of measures of asymmetry.

  13. On perturbative azimuthal asymmetry at RHIC

    SciTech Connect

    Rezaeian, A. H.

    2008-10-13

    We investigate the azimuthal asymmetry of partons and photons produced at the initial stage of nuclear collisions at the RHIC energy originating from quark-nucleus collisions. In our approach, the azimuthal asymmetry results from the correlation between color dipole orientation and impact parameter of the collision. The asymmetry is sensitive to the rapid variation of the nuclear density at the nuclear periphery. We either introduce the color-dipole orientation into the improved Born approximation, or model the dipole partial amplitude which satisfies available DIS data. We conclude that the azimuthal asymmetry coming from these mechanisms can be sizable.

  14. Dimensional and discrete dental trait asymmetry relationships.

    PubMed

    Mayhall, J T; Saunders, S R

    1986-03-01

    Inuit (Eskimos) from the Foxe Basin region of the Northwest Territories, Canada, were studied to ascertain the amount of dimensional and morphological asymmetry in their dentitions. The results indicate that dimensional asymmetry does not appear to be greater on either the maxillary or mandibular teeth. Both types of asymmetry show partial conformity to the model of tooth fields with an increasing amount of asymmetry as one goes distally in each tooth group. The morphological asymmetry exception, the mandibular incisors, follows Dahlberg's "Field Concept." Rank-order correlations between the amount of dimensional asymmetry and morphological asymmetry reveal no detectable patterns. There appear to be no associations between the presence or absence of morphological asymmetry and the size of the tooth. This lack of association might be explained by differences in developmental timing of tooth dimensions and morphological traits; however, such a hypothesis requires experimental testing. In this population and those for which published results are available, it is practically impossible to overcome the "noise" level and test recent hypotheses regarding random dental asymmetry. PMID:3706516

  15. Biomolecular Structure Determination with Divide and Concur

    NASA Astrophysics Data System (ADS)

    Kallus, Yoav; Elser, Veit

    2009-03-01

    Divide and concur (D-C) is a general computational approach, designed for the solution of highly frustrated problems. Recently applied to the problems of disk packing, the kissing number problem, and 3-SAT, it was competitive or outperformed special-purpose methods.ootnotetextS. Gravel and V. Elser, Phys. Rev. E 78, 036706 (2008) We present a method for applying the D-C framework to the problem of biomolecular structure determination. From a list of geometric constraints on groups of atoms in the molecule, we construct a deterministic iterative map that efficiently searches for structures simultaneously satisfying all constraints. As our method eschews an energy function and its minimization to focus on geometric constraints, it can very naturally integrate with the geometric constraints due to chemistry and physics, experimental constraints due to NMR data or many other experimental or biological hints. We present some results of our method.

  16. Whistled Turkish alters language asymmetries.

    PubMed

    Güntürkün, Onur; Güntürkün, Monika; Hahn, Constanze

    2015-08-17

    Whistled languages represent an experiment of nature to test the widely accepted view that language comprehension is to some extent governed by the left hemisphere in a rather input-invariant manner. Indeed, left-hemisphere superiority has been reported for atonal and tonal languages, click consonants, writing and sign languages. The right hemisphere is specialized to encode acoustic properties like spectral cues, pitch, and melodic lines and plays a role for prosodic communicative cues. Would left hemisphere language superiority change when subjects had to encode a language that is constituted by acoustic properties for which the right hemisphere is specialized? Whistled Turkish uses the full lexical and syntactic information of vocal Turkish, and transforms this into whistles to transport complex conversations with constrained whistled articulations over long distances. We tested the comprehension of vocally vs. whistled identical lexical information in native whistle-speaking people of mountainous Northeast Turkey. We discovered that whistled language comprehension relies on symmetric hemispheric contributions, associated with a decrease of left and a relative increase of right hemispheric encoding mechanisms. Our results demonstrate that a language that places high demands on right-hemisphere typical acoustical encoding creates a radical change in language asymmetries. Thus, language asymmetry patterns are in an important way shaped by the physical properties of the lexical input. PMID:26294179

  17. Asymmetry in the epithalamus of vertebrates

    PubMed Central

    L. CONCHA, MIGUEL; W. WILSON, STEPHEN

    2001-01-01

    The epithalamus is a major subdivision of the diencephalon constituted by the habenular nuclei and pineal complex. Structural asymmetries in this region are widespread amongst vertebrates and involve differences in size, neuronal organisation, neurochemistry and connectivity. In species that possess a photoreceptive parapineal organ, this structure projects asymmetrically to the left habenula, and in teleosts it is also situated on the left side of the brain. Asymmetries in size between the left and right sides of the habenula are often associated with asymmetries in neuronal organisation, although these two types of asymmetry follow different evolutionary courses. While the former is more conspicuous in fishes (with the exception of teleosts), asymmetries in neuronal organisation are more robust in amphibia and reptiles. Connectivity of the parapineal organ with the left habenula is not always coupled with asymmetries in habenular size and/or neuronal organisation suggesting that, at least in some species, assignment of parapineal and habenular asymmetries may be independent events. The evolutionary origins of epithalamic structures are uncertain but asymmetry in this region is likely to have existed at the origin of the vertebrate, perhaps even the chordate, lineage. In at least some extant vertebrate species, epithalamic asymmetries are established early in development, suggesting a genetic regulation of asymmetry. In some cases, epigenetic factors such as hormones also influence the development of sexually dimorphic habenular asymmetries. Although the genetic and developmental mechanisms by which neuroanatomical asymmetries are established remain obscure, some clues regarding the mechanisms underlying laterality decisions have recently come from studies in zebrafish. The Nodal signalling pathway regulates laterality by biasing an otherwise stochastic laterality decision to the left side of the epithalamus. This genetic mechanism ensures a consistency of

  18. Scintillation Monitoring Using Asymmetry Index

    NASA Astrophysics Data System (ADS)

    Shaikh, Muhammad Mubasshir; Mahrous, Ayman; Abdallah, Amr; Notarpietro, Riccardo

    Variation in electron density can have significant effect on GNSS signals in terms of propagation delay. Ionospheric scintillation can be caused by rapid change of such delay, specifically, when they last for a longer period of time. Ionospheric irregularities that account for scintillation may vary significantly in spatial range and drift with the background plasma at speeds of 45 to 130 m/sec. These patchy irregularities may occur several times during night, e.g. in equatorial region, with the patches move through the ray paths of the GNSS satellite signals. These irregularities are often characterized as either ‘large scale’ (which can be as large as several hundred km in East-West direction and many times that in the North-South direction) or ‘small scale’ (which can be as small as 1m). These small scale irregularities are regarded as the main cause of scintillation [1,2]. In normal solar activity conditions, the mid-latitude ionosphere is not much disturbed. However, during severe magnetic storms, the aurora oval extends towards the equator and the equator anomaly region may stretched towards poles extending the scintillation phenomena more typically associated with those regions into mid-latitudes. In such stormy conditions, the predicted TEC may deviate largely from the true value of the TEC both at low and mid-latitudes due to which GNSS applications may be strongly degraded. This work is an attempt to analyze ionospheric scintillation (S4 index) using ionospheric asymmetry index [3]. The asymmetry index is based on trans-ionospheric propagation between GPS and LEO satellites in a radio occultation (RO) scenario, using background ionospheric data provided by MIDAS [4]. We attempted to simulate one of the recent geomagnetic storms (NOAA scale G4) occurred over low/mid-latitudes. The storm started on 26 September 2011 at UT 18:00 and lasted until early hours of 27 September 2011. The scintillation data for the storm was taken from an ionospheric

  19. The cellular basis of aqueous outflow regulation.

    PubMed

    Francis, B A; Alvarado, J

    1997-04-01

    This review begins with an introduction to the concept of the cellular regulation of aqueous outflow, current methods used for its study, and the cell types that are known to participate in this process. Current research in the field is divided into work on cell properties, cell products and extracellular matrix, cytoskeletal and structural changes, and drug interactions. PMID:10168352

  20. Nasal Septal Deviation and Facial Skeletal Asymmetries.

    PubMed

    Hartman, Christopher; Holton, Nathan; Miller, Steven; Yokley, Todd; Marshall, Steven; Srinivasan, Sreedevi; Southard, Thomas

    2016-03-01

    During ontogeny, the nasal septum exerts a morphogenetic influence on the surrounding facial skeleton. While the influence of the septum is well established in long snouted animal models, its role in human facial growth is less clear. If the septum is a facial growth center in humans, we would predict that deviated septal growth would be associated with facial skeletal asymmetries. Using computed tomographic (CT) scans of n = 55 adult subjects, the purpose of this study was to test whether there is a correlation between septal deviation and facial asymmetries using three-dimensional (3D) geometric morphometric techniques. We calculated deviation as a percentage of septal volume relative to the volume of a modeled non-deviated septum. We then recorded skeletal landmarks representing the nasal, palatal, and lateral facial regions. Landmark data were superimposed using Procrustes analysis. First, we examined the correlation between nasal septal deviation and the overall magnitude of asymmetry. Next, we assessed whether there was a relationship between nasal septal deviation and more localized aspects of asymmetry using multivariate regression analysis. Our results indicate that while there was no correlation between septal deviation and the overall magnitude of asymmetry, septal deviation was associated with asymmetry primarily in the nasal floor and the palatal region. Septal deviation was unassociated with asymmetries in the lateral facial skeleton. Though we did not test the causal relationship between nasal septal deviation and facial asymmetry, our results suggest that the nasal septum may have an influence on patterns of adult facial form. PMID:26677010

  1. Atypical Alpha Asymmetry in Adults with ADHD

    ERIC Educational Resources Information Center

    Hale, T. Sigi; Smalley, Susan L.; Hanada, Grant; Macion, James; McCracken, James T.; McGough, James J.; Loo, Sandra K.

    2009-01-01

    Introduction: A growing body of literature suggests atypical cerebral asymmetry and interhemispheric interaction in ADHD. A common means of assessing lateralized brain function in clinical populations has been to examine the relative proportion of EEG alpha activity (8-12 Hz) in each hemisphere (i.e., alpha asymmetry). Increased rightward alpha…

  2. Determining Asymmetry Of A Weld Puddle

    NASA Technical Reports Server (NTRS)

    Gutow, David A.

    1992-01-01

    Sensing-and-data-processing subsystem provides information of asymmetry of weld puddle with respect to original midplane of joint. Shape of puddle inferred from surface-temperature distribution. Part of welding-control system which enables system to correct for asymmetry.

  3. Asymmetry and Performance: Toward a Neurodevelopmental Theory

    ERIC Educational Resources Information Center

    Boles, David B.; Barth, Joan M.; Merrill, Edward C.

    2008-01-01

    Hemispheric asymmetry implies the existence of developmental influences that affect one hemisphere more than the other. However, those influences are poorly understood. One simple view is that asymmetry may exist because of a relationship between a mental process' degree of lateralization and how well it functions. Data scaling issues have largely…

  4. Visual Search Asymmetry with Uncertain Targets

    ERIC Educational Resources Information Center

    Saiki, Jun; Koike, Takahiko; Takahashi, Kohske; Inoue, Tomoko

    2005-01-01

    The underlying mechanism of search asymmetry is still unknown. Many computational models postulate top-down selection of target-defining features as a crucial factor. This feature selection account implies, and other theories implicitly assume, that predefined target identity is necessary for search asymmetry. The authors tested the validity of…

  5. The evolution and genetics of cerebral asymmetry

    PubMed Central

    Corballis, Michael C.

    2008-01-01

    Handedness and cerebral asymmetry are commonly assumed to be uniquely human, and even defining characteristics of our species. This is increasingly refuted by the evidence of behavioural asymmetries in non-human species. Although complex manual skill and language are indeed unique to our species and are represented asymmetrically in the brain, some non-human asymmetries appear to be precursors, and others are shared between humans and non-humans. In all behavioural and cerebral asymmetries so far investigated, a minority of individuals reverse or negate the dominant asymmetry, suggesting that such asymmetries are best understood in the context of the overriding bilateral symmetry of the brain and body, and a trade-off between the relative advantages and disadvantages of symmetry and asymmetry. Genetic models of handedness, for example, typically postulate a gene with two alleles, one disposing towards right-handedness and the other imposing no directional influence. There is as yet no convincing evidence as to the location of this putative gene, suggesting that several genes may be involved, or that the gene may be monomorphic with variations due to environmental or epigenetic influences. Nevertheless, it is suggested that, in behavioural, neurological and evolutionary terms, it may be more profitable to examine the degree rather than the direction of asymmetry. PMID:19064358

  6. Beyond apoptosis: the mechanism and function of phosphatidylserine asymmetry in the membrane of activating mast cells.

    PubMed

    Rysavy, Noel M; Shimoda, Lori M N; Dixon, Alyssa M; Speck, Mark; Stokes, Alexander J; Turner, Helen; Umemoto, Eric Y

    2014-01-01

    Loss of plasma membrane asymmetry is a hallmark of apoptosis, but lipid bilayer asymmetry and loss of asymmetry can contribute to numerous cellular functions and responses that are independent of programmed cell death. Exofacial exposure of phosphatidylserine occurs in lymphocytes and mast cells after antigenic stimulation and in the absence of apoptosis, suggesting that there is a functional requirement for phosphatidylserine exposure in immunocytes. In this review we examine current ideas as to the nature of this functional role in mast cell activation. Mechanistically, there is controversy as to the candidate proteins responsible for phosphatidylserine translocation from the internal to external leaflet, and here we review the candidacies of mast cell PLSCR1 and TMEM16F. Finally we examine the potential relationship between functionally important mast cell membrane perturbations and phosphatidylserine exposure during activation. PMID:25759911

  7. Beyond apoptosis: The mechanism and function of phosphatidylserine asymmetry in the membrane of activating mast cells

    PubMed Central

    Rysavy, Noel M.; Shimoda, Lori M. N.; Dixon, Alyssa M.; Speck, Mark; Stokes, Alexander J.; Turner, Helen; Umemoto, Eric Y.

    2014-01-01

    Loss of plasma membrane asymmetry is a hallmark of apoptosis, but lipid bilayer asymmetry and loss of asymmetry can contribute to numerous cellular functions and responses that are independent of programmed cell death. Exofacial exposure of phosphatidylserine occurs in lymphocytes and mast cells after antigenic stimulation and in the absence of apoptosis, suggesting that there is a functional requirement for phosphatidylserine exposure in immunocytes. In this review we examine current ideas as to the nature of this functional role in mast cell activation. Mechanistically, there is controversy as to the candidate proteins responsible for phosphatidylserine translocation from the internal to external leaflet, and here we review the candidacies of mast cell PLSCR1 and TMEM16F. Finally we examine the potential relationship between functionally important mast cell membrane perturbations and phosphatidylserine exposure during activation. PMID:25759911

  8. Bridging the Divide between Science and Journalism

    PubMed Central

    2010-01-01

    There are countless reasons nearly every scientist should learn how to communicate effectively with the media, including increased understanding of critical research findings to attract or sustain funding and build new professional partnerships that will further propel forward research. But where do scientists begin? Bridging the Divide between Science and Journalism offers practical tips for any scientist looking to work with the media. Given the traditional and internet-based sources for medical research and healthcare-related news now available, it is imperative that scientists know how to communicate their latest findings through the appropriate channels. The credible media channels are managed by working journalists, so learning how to package vast, technical research in a form that is appetizing and "bite-sized" in order to get their attention, is an art. Reducing years of research into a headline can be extremely difficult and certainly doesn't come naturally to every scientist, so this article provides suggestions on how to work with the media to communicate your findings. PMID:20219123

  9. Bridging the divide between science and journalism.

    PubMed

    Van Eperen, Laura; Marincola, Francesco M; Strohm, Jennifer

    2010-01-01

    There are countless reasons nearly every scientist should learn how to communicate effectively with the media, including increased understanding of critical research findings to attract or sustain funding and build new professional partnerships that will further propel forward research. But where do scientists begin? Bridging the Divide between Science and Journalism offers practical tips for any scientist looking to work with the media.Given the traditional and internet-based sources for medical research and healthcare-related news now available, it is imperative that scientists know how to communicate their latest findings through the appropriate channels. The credible media channels are managed by working journalists, so learning how to package vast, technical research in a form that is appetizing and "bite-sized" in order to get their attention, is an art. Reducing years of research into a headline can be extremely difficult and certainly doesn't come naturally to every scientist, so this article provides suggestions on how to work with the media to communicate your findings. PMID:20219123

  10. Anatomic Brain Asymmetry in Vervet Monkeys

    PubMed Central

    Fears, Scott C.; Scheibel, Kevin; Abaryan, Zvart; Lee, Chris; Service, Susan K.; Jorgensen, Matthew J.; Fairbanks, Lynn A.; Cantor, Rita M.; Freimer, Nelson B.; Woods, Roger P.

    2011-01-01

    Asymmetry is a prominent feature of human brains with important functional consequences. Many asymmetric traits show population bias, but little is known about the genetic and environmental sources contributing to inter-individual variance. Anatomic asymmetry has been observed in Old World monkeys, but the evidence for the direction and extent of asymmetry is equivocal and only one study has estimated the genetic contributions to inter-individual variance. In this study we characterize a range of qualitative and quantitative asymmetry measures in structural brain MRIs acquired from an extended pedigree of Old World vervet monkeys (n = 357), and implement variance component methods to estimate the proportion of trait variance attributable to genetic and environmental sources. Four of six asymmetry measures show pedigree-level bias and one of the traits has a significant heritability estimate of about 30%. We also found that environmental variables more significantly influence the width of the right compared to the left prefrontal lobe. PMID:22205941

  11. Establishment and expression of cellular polarity in fucoid zygotes.

    PubMed Central

    Kropf, D L

    1992-01-01

    . Approximately halfway through the first cell cycle, the latent polarity is expressed morphologically in the form of rhizoid growth. Elongation is by tip growth and does not appear to be fundamentally different from tip growth in other organisms. The zygote always divides perpendicular to the growth axis, and this is controlled by the microtubule cytoskeleton. Two microtubule-organizing centers on the nuclear envelope rotate such that they align with the growth axis. They then serve as spindle poles during mitosis. Cytokinesis bisects the axial spindle, resulting in a transverse crosswall. Although the chronology of cellular events associated with polarity is by now rather detailed, causal mechanisms remain obscure. Images PMID:1620068

  12. Asymmetry effects in fragment production

    NASA Astrophysics Data System (ADS)

    Kaur, Manpreet; Kaur, Varinderjit

    2016-05-01

    The production of different fragments has been studied by taking into account the mass asymmetry of the reaction and employing the momentum dependent interactions. Two different set of asymmetric reactions have been analyzed while keeping Atotal fixed using soft momentum dependent equation of state. Our results indicate that the impact of momentum dependent interactions is different in lighter projectile systems as compared to heavier ones. The comparative analysis of IQMD simulations with the experimental data in case of heavier projectile and lighter target system for the reaction of 197Au+27Al (η = 0.7) at E = 600 MeV/nucleon shows that with the inclusion of MDI we are able, upto some extent, to reproduce the experimental universality of rise and fall of intermediate mass fragments (IMFs).

  13. Collins Asymmetry at Hadron Colliders

    SciTech Connect

    Yuan, Feng

    2008-01-17

    We study the Collins effect in the azimuthal asymmetricdistribution of hadrons inside a high energy jet in the single transversepolarized proton proton scattering. From the detailed analysis ofone-gluon and two-gluon exchange diagrams contributions, the Collinsfunction is found the same as that in the semi-inclusive deep inelasticscattering and e+e- annihilations. The eikonal propagators in thesediagrams do not contribute to the phase needed for the Collins-typesingle spin asymmetry, and the universality is derived as a result of theWard identity. We argue that this conclusion depends on the momentum flowof the exchanged gluon and the kinematic constraints in the fragmentationprocess, and is generic and model-independent.

  14. Black-white asymmetry in visual perception.

    PubMed

    Lu, Zhong-Lin; Sperling, George

    2012-01-01

    With eleven different types of stimuli that exercise a wide gamut of spatial and temporal visual processes, negative perturbations from mean luminance are found to be typically 25% more effective visually than positive perturbations of the same magnitude (range 8-67%). In Experiment 12, the magnitude of the black-white asymmetry is shown to be a saturating function of stimulus contrast. Experiment 13 shows black-white asymmetry primarily involves a nonlinearity in the visual representation of decrements. Black-white asymmetry in early visual processing produces even-harmonic distortion frequencies in all ordinary stimuli and in illusions such as the perceived asymmetry of optically perfect sine wave gratings. In stimuli intended to stimulate exclusively second-order processing in which motion or shape are defined not by luminance differences but by differences in texture contrast, the black-white asymmetry typically generates artifactual luminance (first-order) motion and shape components. Because black-white asymmetry pervades psychophysical and neurophysiological procedures that utilize spatial or temporal variations of luminance, it frequently needs to be considered in the design and evaluation of experiments that involve visual stimuli. Simple procedures to compensate for black-white asymmetry are proposed. PMID:22984221

  15. Black–white asymmetry in visual perception

    PubMed Central

    Lu, Zhong-Lin; Sperling, George

    2012-01-01

    With eleven different types of stimuli that exercise a wide gamut of spatial and temporal visual processes, negative perturbations from mean luminance are found to be typically 25% more effective visually than positive perturbations of the same magnitude (range 8–67%). In Experiment 12, the magnitude of the black–white asymmetry is shown to be a saturating function of stimulus contrast. Experiment 13 shows black–white asymmetry primarily involves a nonlinearity in the visual representation of decrements. Black–white asymmetry in early visual processing produces even-harmonic distortion frequencies in all ordinary stimuli and in illusions such as the perceived asymmetry of optically perfect sine wave gratings. In stimuli intended to stimulate exclusively second-order processing in which motion or shape are defined not by luminance differences but by differences in texture contrast, the black–white asymmetry typically generates artifactual luminance (first-order) motion and shape components. Because black–white asymmetry pervades psychophysical and neurophysiological procedures that utilize spatial or temporal variations of luminance, it frequently needs to be considered in the design and evaluation of experiments that involve visual stimuli. Simple procedures to compensate for black–white asymmetry are proposed. PMID:22984221

  16. Cellular Stress Responses and Monitored Cellular Activities.

    PubMed

    Sawa, Teiji; Naito, Yoshifumi; Kato, Hideya; Amaya, Fumimasa

    2016-08-01

    To survive, organisms require mechanisms that enable them to sense changes in the outside environment, introduce necessary responses, and resist unfavorable distortion. Consequently, through evolutionary adaptation, cells have become equipped with the apparatus required to monitor their fundamental intracellular processes and the mechanisms needed to try to offset malfunction without receiving any direct signals from the outside environment. It has been shown recently that eukaryotic cells are equipped with a special mechanism that monitors their fundamental cellular functions and that some pathogenic proteobacteria can override this monitoring mechanism to cause harm. The monitored cellular activities involved in the stressed intracellular response have been researched extensively in Caenorhabditis elegans, where discovery of an association between key mitochondrial activities and innate immune responses was named "cellular associated detoxification and defenses (cSADD)." This cellular surveillance pathway (cSADD) oversees core cellular activities such as mitochondrial respiration and protein transport into mitochondria, detects xenobiotics and invading pathogens, and activates the endocrine pathways controlling behavior, detoxification, and immunity. The cSADD pathway is probably associated with cellular responses to stress in human inflammatory diseases. In the critical care field, the pathogenesis of lethal inflammatory syndromes (e.g., respiratory distress syndromes and sepsis) involves the disturbance of mitochondrial respiration leading to cell death. Up-to-date knowledge about monitored cellular activities and cSADD, especially focusing on mitochondrial involvement, can probably help fill a knowledge gap regarding the pathogenesis of lethal inflammatory syndromes in the critical care field. PMID:26954943

  17. Relic Density of Neutrinos with Primordial Asymmetries

    SciTech Connect

    Pastor, Sergio; Pinto, Teguayco; Raffelt, Georg G.

    2009-06-19

    We study flavor oscillations in the early Universe, assuming primordial neutrino-antineutrino asymmetries. Including collisions and pair processes in the kinetic equations, we not only estimate the degree of flavor equilibration, but for the first time also kinetic equilibration among neutrinos and with the ambient plasma. Typically, the restrictive big-bang nucleosynthesis bound on the nu{sub e}nu{sub e} asymmetry indeed applies to all flavors as claimed in the previous literature, but fine-tuned initial asymmetries always allow for a large surviving neutrino excess radiation that may show up in precision cosmological data.

  18. QCD coherence and the top quark asymmetry

    NASA Astrophysics Data System (ADS)

    Skands, Peter; Webber, Bryan; Winter, Jan

    2012-07-01

    Coherent QCD radiation in the hadroproduction of top quark pairs leads to a forward-backward asymmetry that grows more negative with increasing transverse momentum of the pair. This feature is present in Monte Carlo event generators with coherent parton showering, even though the production process is treated at leading order and has no intrinsic asymmetry before showering. In addition, depending on the treatment of recoils, showering can produce a positive contribution to the inclusive asymmetry. We explain the origin of these features, compare them in fixed-order calculations and the H erwig++, P ythia and S herpa event generators, and discuss their implications.

  19. Relic density of neutrinos with primordial asymmetries.

    PubMed

    Pastor, Sergio; Pinto, Teguayco; Raffelt, Georg G

    2009-06-19

    We study flavor oscillations in the early Universe, assuming primordial neutrino-antineutrino asymmetries. Including collisions and pair processes in the kinetic equations, we not only estimate the degree of flavor equilibration, but for the first time also kinetic equilibration among neutrinos and with the ambient plasma. Typically, the restrictive big-bang nucleosynthesis bound on the nu_{e}nu[over]_{e} asymmetry indeed applies to all flavors as claimed in the previous literature, but fine-tuned initial asymmetries always allow for a large surviving neutrino excess radiation that may show up in precision cosmological data. PMID:19658994

  20. Management of Asymmetry After Breast Reduction.

    PubMed

    Garcia, Onelio

    2016-04-01

    Breast reduction surgery has achieved one of the highest patient satisfaction rates among plastic surgery procedures. Most of the complications encountered are usually minor and related to wound healing. Revision surgery to address these problems is common and usually consists of scar revisions. Postoperative breast asymmetry of a mild degree is also common; however, postoperative asymmetry severe enough to warrant surgical revision is a rare event, occurring in less than 1% of cases. Postmammaplasty revision surgery needs to be individualized. The asymmetry could be the result of nipple malposition or it could consist of a volume or shape discrepancy between the breast mounds. PMID:27012796

  1. Cellular Phone Towers

    MedlinePlus

    ... the call. How are people exposed to the energy from cellular phone towers? As people use cell ... where people can be exposed to them. The energy from a cellular phone tower antenna, like that ...

  2. Asymmetry in body composition in female hockey players.

    PubMed

    Krzykała, M; Leszczyński, P

    2015-08-01

    The aim of the study was to determine if a sport in which one side of the body is dominant, like field hockey, influences regional body composition and bone mineral density (BMD) distribution in particular body segments, and whether the sporting level is a determining factor. Dual energy X-ray absorptiometry (DXA) method (Lunar Prodigy Advance; General Electric, Madison, USA) with the whole body scan was used to measure bone mineral density, fat mass and lean mass in 31 female field hockey players divided according to their sporting level. The morphological asymmetry level was assessed between two body sides and body segments in athletes from the National Team (n=17) and from the Youth Team (n=14) separately and between groups. Bone mineral density in the lower extremity and of the trunk was significantly asymmetric in favor of the left side in the National Team. In the case of the Youth Team, only the trunk BMD indicated clear left-right difference with left side dominance. Both the lean mass and fat mass values were relatively higher on the left side of all body segments and it related to both analyzed groups of athletes. The present study shows that playing field hockey contributes to laterality in body composition and BMD and that the sporting level is a determining factor. In most cases the left side dominated. A greater asymmetry level was observed in more experienced female field hockey players. PMID:26077573

  3. Hierarchical cellular materials

    SciTech Connect

    Gibson, L.J.

    1991-01-01

    In this paper a method for estimating the contributions of both the composite and the cellular microstructures to the overall material properties and the mechanical efficiency of natural cellular solids will be described. The method will be demonstrated by focusing on the Young's modulus; similar techniques can be used for other material properties. The results suggest efficient microstructures for engineered cellular materials.

  4. Hierarchical cellular materials

    SciTech Connect

    Gibson, L.J.

    1991-12-31

    In this paper a method for estimating the contributions of both the composite and the cellular microstructures to the overall material properties and the mechanical efficiency of natural cellular solids will be described. The method will be demonstrated by focusing on the Young`s modulus; similar techniques can be used for other material properties. The results suggest efficient microstructures for engineered cellular materials.

  5. Pars triangularis asymmetry and language dominance.

    PubMed Central

    Foundas, A L; Leonard, C M; Gilmore, R L; Fennell, E B; Heilman, K M

    1996-01-01

    The pars triangular is a portion of Broca's area. The convolutions that form the inferior and caudal extent of the pars triangularis include the anterior horizontal and anterior ascending rami of the sylvian fissure, respectively. To learn if there are anatomic asymmetries of the pars triangularis, these convolutions were measured on volumetric magnetic resonance imaging scans of 11 patients who had undergone selective hemispheric anesthesia (Wada testing) to determine hemispheric speech and language lateralization. Of the 10 patients with language lateralized to the left hemisphere, 9 had a leftward asymmetry of the pars triangularis. The 1 patient with language lateralized to the right hemisphere had a significant rightward asymmetry of the pars triangularis. Our data suggest that asymmetries of the pars triangularis may be related to speech-language lateralization. Images Fig. 1 PMID:8570622

  6. Symmetry and asymmetry in the human brain

    NASA Astrophysics Data System (ADS)

    Hugdahl, Kenneth

    2005-10-01

    Structural and functional asymmetry in the human brain and nervous system is reviewed in a historical perspective, focusing on the pioneering work of Broca, Wernicke, Sperry, and Geschwind. Structural and functional asymmetry is exemplified from work done in our laboratory on auditory laterality using an empirical procedure called dichotic listening. This also involves different ways of validating the dichotic listening procedure against both invasive and non-invasive techniques, including PET and fMRI blood flow recordings. A major argument is that the human brain shows a substantial interaction between structurally, or "bottom-up" asymmetry and cognitively, or "top-down" modulation, through a focus of attention to the right or left side in auditory space. These results open up a more dynamic and interactive view of functional brain asymmetry than the traditional static view that the brain is lateralized, or asymmetric, only for specific stimuli and stimulus properties.

  7. Di-hadron asymmetry and interplay between transversity induced asymmetries in hadron leptoproduction at COMPASS

    NASA Astrophysics Data System (ADS)

    Sbrizzai, Giulio

    2016-02-01

    New results on the transverse spin azimuthal asymmetries in semi-inclusive DIS reactions extracted by the COMPASS Collaboration from the data collected with a transversely polarised proton target are presented. A noticeable similarity between the Collins asymmetry and the dihadron asymmetry, already been observed and reported, triggered a more deep investigation on the angular correlations and the relevant kinematical variables. The resulting phenomenological analysis of the transversity induced asymmetries, presented in this talk, allows to establish quantitative relationships, providing strong indication that the underlying fragmentation mechanisms are all driven by a common physical process.

  8. Baryon asymmetry, inflation and squeezed states

    SciTech Connect

    Bambah, Bindu A. . E-mail: bbsp@uohyd.ernet.in; Chaitanya, K.V.S. Shiv; Mukku, C.

    2007-04-15

    We use the general formalism of squeezed rotated states to calculate baryon asymmetry in the wake of inflation through parametric amplification. We base our analysis on a B and CP violating Lagrangian in an isotropically expanding universe. The B and CP violating terms originate from the coupling of complex fields with non-zero baryon number to a complex background inflaton field. We show that a differential amplification of particle and antiparticle modes gives rise to baryon asymmetry.

  9. Case report: treatment of dental asymmetry.

    PubMed

    Bergamini, A; Melsen, B

    1995-01-01

    The treatment of dental asymmetries often comprises several treatment alternatives. This case report describes the treatment alternatives for an asymmetry generated secondary to surgical removal of an odontoma that included the germ of the lower left lateral incisor. The opening of the space was chosen based on the patient's wish. The asymmetrical biomechanical force system used for the correction of the midline is presented as free-body diagram. PMID:7486238

  10. Bottom production asymmetries at the LHC

    SciTech Connect

    Norrbin, E.; Vogt, R.

    1999-01-01

    We present results on bottom hadron production asymmetries at the LHC within both the Lund string fragmentation model and the intrinsic bottom model. The main aspects of the models are summarized and specific predictions for pp collisions at 14 TeV are given. Asymmetries are found to be very small at central rapidities increasing to a few percent at forward rapidities. At very large rapidities intrinsic production could dominate but this region is probably out of reach of any experiment.

  11. Experimental Tests on the Lifetime Asymmetry

    NASA Astrophysics Data System (ADS)

    Shi, Zhi-Qiang; Ni, Guang-Jiong

    The experimental test problem of the left-right polarization-dependent lifetime asymmetry is discussed. It shows that the existing experiments cannot demonstrate the lifetime asymmetry to be right or wrong after analyzing the measurements on the neutron, the muon and the tau lifetime, as well as the g-2 experiment. However, it is pointed out emphatically that the SLD and the E158 experiments, the measurements of the left-right integrated cross section asymmetry in Z boson production by e+e- collisions and by electron-electron Møller scattering, can indirectly demonstrate the lifetime asymmetry. In order to directly demonstrate the lifetime asymmetry, we propose some possible experiments on the decays of polarized muons. The precise measurement of the lifetime asymmetry could have important significance for building a muon collider, also in cosmology and astrophysics. It would provide a sensitive test of the standard model in particle physics and allow for exploration of the possible V+A interactions.

  12. Asymmetries observed in Saturn's magnetopause geometry

    NASA Astrophysics Data System (ADS)

    Pilkington, N. M.; Achilleos, N.; Arridge, C. S.; Guio, P.; Masters, A.; Ray, L. C.; Sergis, N.; Thomsen, M. F.; Coates, A. J.; Dougherty, M. K.

    2015-09-01

    For over 10 years, the Cassini spacecraft has patrolled Saturn's magnetosphere and observed its magnetopause boundary over a wide range of prevailing solar wind and interior plasma conditions. We now have data that enable us to resolve a significant dawn-dusk asymmetry and find that the magnetosphere extends farther from the planet on the dawnside of the planet by 7 ± 1%. In addition, an opposing dawn-dusk asymmetry in the suprathermal plasma pressure adjacent to the magnetopause has been observed. This probably acts to reduce the size asymmetry and may explain the discrepancy between the degree of asymmetry found here and a similar asymmetry found by Kivelson and Jia (2014) using MHD simulations. Finally, these observations sample a wide range of season, allowing the "intrinsic" polar flattening (14 ± 1%) caused by the magnetodisc to be separated from the seasonally induced north-south asymmetry in the magnetopause shape found theoretically (5 ± 1% when the planet's magnetic dipole is tilted away from the Sun by 10-17°).

  13. Cryptic asymmetry: unreliable signals mask asymmetric performance of crayfish weapons.

    PubMed

    Angilletta, Michael J; Wilson, Robbie S

    2012-08-23

    Animals commonly use their limbs as signals and weapons during territorial aggression. Asymmetries of limb performance that do not relate to asymmetries of limb size (cryptic asymmetry) could substantially affect disputes, but this phenomenon has not been considered beyond primates. We investigated cryptic asymmetry in male crayfish (Cherax dispar), which commonly use unreliable signals of strength during aggression. Although the strength of a chela can vary by an order of magnitude for a given size, we found repeatable asymmetries of strength that were only weakly related to asymmetries of size. Size-adjusted strength of chelae and the asymmetry of strength between chelae were highly repeatable between environmental conditions, suggesting that asymmetries of strength stemmed from variation in capacity rather than motivation. Cryptic asymmetry adds another dimension of uncertainty during conflict between animals, which could influence the evolution of unreliable signals and morphological asymmetry. PMID:22417793

  14. Cryptic asymmetry: unreliable signals mask asymmetric performance of crayfish weapons

    PubMed Central

    Angilletta, Michael J.; Wilson, Robbie S.

    2012-01-01

    Animals commonly use their limbs as signals and weapons during territorial aggression. Asymmetries of limb performance that do not relate to asymmetries of limb size (cryptic asymmetry) could substantially affect disputes, but this phenomenon has not been considered beyond primates. We investigated cryptic asymmetry in male crayfish (Cherax dispar), which commonly use unreliable signals of strength during aggression. Although the strength of a chela can vary by an order of magnitude for a given size, we found repeatable asymmetries of strength that were only weakly related to asymmetries of size. Size-adjusted strength of chelae and the asymmetry of strength between chelae were highly repeatable between environmental conditions, suggesting that asymmetries of strength stemmed from variation in capacity rather than motivation. Cryptic asymmetry adds another dimension of uncertainty during conflict between animals, which could influence the evolution of unreliable signals and morphological asymmetry. PMID:22417793

  15. 37 CFR 2.87 - Dividing an application.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2011-07-01 2011-07-01 false Dividing an application. 2.87 Section 2.87 Patents, Trademarks, and Copyrights UNITED STATES PATENT AND TRADEMARK OFFICE, DEPARTMENT OF COMMERCE RULES OF PRACTICE IN TRADEMARK CASES Classification § 2.87 Dividing an application. (a) Application may be divided. An application...

  16. Force-production asymmetry in male and female athletes of differing strength levels.

    PubMed

    Bailey, Christopher A; Sato, Kimitake; Burnett, Angus; Stone, Michael H

    2015-05-01

    The purpose of this investigation was to determine the existence of bilateral strength and force-production asymmetry and evaluate possible differences based on sex, as well as strength level. Asymmetry was assessed during weight-distribution (WtD) testing, unloaded and lightly loaded static- (SJ) and countermovement-jump (CMJ) testing, and isometric midthigh-pull (IMTP) strength testing. Subjects included 63 athletes (31 male, 32 female) for WtD, SJ, and CMJ tests, while 129 athletes (64 male, 65 female) participated in IMTP testing. Independent-samples t tests were used to determine possible differences in asymmetry magnitude between males and females, as well as between strong and weak athletes. Cohen d effect-size (ES) estimates were also used to estimate difference magnitudes. Statistically different asymmetry levels with moderate to strong ESs were seen between males and females in WtD, 0-kg SJ (peak force [PF]), 20-kg SJ (peak power [PP]), 0-kg CMJ (PF, PP, net impulse), and 20-kg CMJ (PF), but no statistical differences were observed in IMTP variables. Dividing the sample into strong and weak groups produced statistically significant differences with strong ES estimates in IMTP PF and rate of force development, and many ESs in jump symmetry variables increased. The results of this investigation indicate that females may be more prone to producing forces asymmetrically than males during WtD and jumping tasks. Similarly, weaker athletes displayed more asymmetry than stronger athletes. This may indicate that absolute strength may play a larger role in influencing asymmetry magnitude than sex. PMID:25394294

  17. Toroidal current asymmetry in tokamak disruptions

    SciTech Connect

    Strauss, H. R.

    2014-10-15

    It was discovered on JET that disruptions were accompanied by toroidal asymmetry of the toroidal plasma current I{sub ϕ}. It was found that the toroidal current asymmetry was proportional to the vertical current moment asymmetry with positive sign for an upward vertical displacement event (VDE) and negative sign for a downward VDE. It was observed that greater displacement leads to greater measured I{sub ϕ} asymmetry. Here, it is shown that this is essentially a kinematic effect produced by a VDE interacting with three dimensional MHD perturbations. The relation of toroidal current asymmetry and vertical current moment is calculated analytically and is verified by numerical simulations. It is shown analytically that the toroidal variation of the toroidal plasma current is accompanied by an equal and opposite variation of the toroidal current flowing in a thin wall surrounding the plasma. These currents are connected by 3D halo current, which is π/2 radians out of phase with the n = 1 toroidal current variations.

  18. Measurement of Collins asymmetry at BESIII

    NASA Astrophysics Data System (ADS)

    Lyu, Xiao-Rui

    2016-02-01

    In this talk, I present the recent measurement of the Collins fragmentation function based on a set of 62 pb-1 e+e- annihilation data at √s = 3.65 GeV collected with the BESIII detector at the BEPCII storage rings. In this work, the azimuthal asymmetries of two charged pions in the inclusive process e+e- → ππX are explored. These asymmetries can be attributed to the Collins fragmentation function, which describes the behavior of a hadron produced from a transversely polarized quark. The corresponding four-momentum transfer of the virtual photon, Q2, is close to the energy scale of the existing semi-inclusive DIS experimental data. We observe a nonzero asymmetry, which increases with increasing pion momentum and also indicates a larger spin-dependent Collins effect than at higher energy scale. The dependence of the asymmetry on the transverse momentum of hadrons to the reference axis is also investigated. The measured asymmetries are important inputs for the global analysis of extracting the quark transversity distribution inside the nucleon, and are valuable to explore the energy evolution of the spin-dependent fragmentation function.

  19. Quantum asymmetry between time and space

    PubMed Central

    2016-01-01

    An asymmetry exists between time and space in the sense that physical systems inevitably evolve over time, whereas there is no corresponding ubiquitous translation over space. The asymmetry, which is presumed to be elemental, is represented by equations of motion and conservation laws that operate differently over time and space. If, however, the asymmetry was found to be due to deeper causes, this conventional view of time evolution would need reworking. Here we show, using a sum-over-paths formalism, that a violation of time reversal (T) symmetry might be such a cause. If T symmetry is obeyed, then the formalism treats time and space symmetrically such that states of matter are localized both in space and in time. In this case, equations of motion and conservation laws are undefined or inapplicable. However, if T symmetry is violated, then the same sum over paths formalism yields states that are localized in space and distributed without bound over time, creating an asymmetry between time and space. Moreover, the states satisfy an equation of motion (the Schrödinger equation) and conservation laws apply. This suggests that the time–space asymmetry is not elemental as currently presumed, and that T violation may have a deep connection with time evolution. PMID:26997899

  20. Asymmetry of the Brain: Development and Implications.

    PubMed

    Duboc, Véronique; Dufourcq, Pascale; Blader, Patrick; Roussigné, Myriam

    2015-01-01

    Although the left and right hemispheres of our brains develop with a high degree of symmetry at both the anatomical and functional levels, it has become clear that subtle structural differences exist between the two sides and that each is dominant in processing specific cognitive tasks. As the result of evolutionary conservation or convergence, lateralization of the brain is found in both vertebrates and invertebrates, suggesting that it provides significant fitness for animal life. This widespread feature of hemispheric specialization has allowed the emergence of model systems to study its development and, in some cases, to link anatomical asymmetries to brain function and behavior. Here, we present some of what is known about brain asymmetry in humans and model organisms as well as what is known about the impact of environmental and genetic factors on brain asymmetry development. We specifically highlight the progress made in understanding the development of epithalamic asymmetries in zebrafish and how this model provides an exciting opportunity to address brain asymmetry at different levels of complexity. PMID:26442849

  1. Least Asymmetry Centering Method and Comparisons

    NASA Astrophysics Data System (ADS)

    Lust, Nate B.; Britt, Daniel; Harrington, Joseph; Nymeyer, Sarah; Stevenson, Kevin B.; Ross, Emily L.; Bowman, William; Fraine, Jonathan

    2014-12-01

    The interpretation of astronomical photometry, astrometry, and orbit determination data depends on accurately and consistently identifying the center of the target object's photometric point spread function in the presence of noise. We introduce a new technique, called least asymmetry, which is designed to find the point about which the distribution is most symmetric. This technique, in addition to the commonly used techniques Gaussian fitting and center of light, was tested against synthetic datasets under realistic ranges of noise and photometric gain. With subpixel accuracy, we compare the determined centers to the known centers and evaluate each method against the simulated conditions. We find that in most cases center of light performs the worst, while Gaussian fitting and least asymmetry are alternately better under different circumstances. Using a real point response function with "reasonable signal-to-noise," we find that least asymmetry provides the most accurate center estimates, and Gaussian centering is the most precise. The least asymmetry routine implemented in the Python Programming Language can be found at https://github.com/natelust/least_asymmetry.

  2. Asymmetry and non-random orientation of the inflight effective beam pattern in the WMAP data

    SciTech Connect

    Chiang, Lung-Yih

    2014-04-20

    Tentative evidence for statistical anisotropy in the Wilkinson Microwave Anisotropy Probe data was alleged to be due to 'insufficient handling of beam asymmetries'. In this paper, we investigate this issue and develop a method to estimate the shape of the inflight effective beam, particularly the asymmetry and azimuthal orientation. We divide the whole map into square patches and exploit the information in the Fourier space. For patches containing bright extragalactic point sources, we can directly estimate their shapes, from which the inflight effective beam can be estimated. For those without, we estimate the pattern from iso-power contours in two-dimensional Fourier space. We show that the inflight effective beam convolving the signal is indeed non-symmetric for most of the sky, and it is not randomly oriented. Around the ecliptic poles, however, the asymmetry is smaller due to the averaging effect from different orientations of the beam from the scan strategy. The orientations of the effective beam with significant asymmetry are parallel to the lines of ecliptic longitude. In the foreground-cleaned Internal Linear Combination map, however, the systematics caused by beam effect is significantly lessened.

  3. ERP evidence for hemispheric asymmetries in exemplar-specific explicit memory access.

    PubMed

    Küper, Kristina; Zimmer, Hubert D

    2015-11-01

    The right cerebral hemisphere (RH) appears to be more effective in representing visual objects as distinct exemplars than the left hemisphere (LH) which is presumably biased towards coding objects at the level of abstract prototypes. As of yet, relatively little is known about the role that asymmetries in exemplar-specificity play at the level of explicit memory retrieval. In the present study, we addressed this issue by examining hemispheric asymmetries in the putative event-related potential (ERP) correlates of familiarity (FN400) and recollection (LPC). In an incidental study phase, pictures of familiar objects were presented centrally. At test, participants performed a memory inclusion task on identical repetitions and different exemplars of study items as well as new items which were presented in only one visual hemifield using the divided visual field technique. With respect to familiarity, we observed exemplar-specific FN400 old/new effects that were more pronounced for identical repetitions than different exemplars, irrespective of the hemisphere governing initial stimulus processing. In contrast, LPC old/new effects were subject to some hemispheric asymmetries indicating that exemplar-specific recollection was more extensive in the RH than in the LH. This further corroborates the idea that hemispheric asymmetries should not be generalized but need to be distinguished not only in different domains but also at different levels of processing. PMID:26279112

  4. An Empirical Analysis of the Determinants of International Digital Divide

    NASA Astrophysics Data System (ADS)

    Yun, Liu

    International Digital Divide is an imbalance state of ICT penetration between countries. This paper analyzes the current status and trends of international digital divide, adopts Gompertz technology diffusion model to verify the determinants of ICT penetration level and diffusion rate separately. Finally, China should use "policy levers" to strengthen international trade cooperation, improve the capability of independent innovation, and achieve Chinese goal of bridging digital divide.

  5. Probing lepton asymmetry with 21 cm fluctuations

    SciTech Connect

    Kohri, Kazunori; Oyama, Yoshihiko; Sekiguchi, Toyokazu; Takahashi, Tomo E-mail: oyamayo@post.kek.jp E-mail: tomot@cc.saga-u.ac.jp

    2014-09-01

    We investigate the issue of how accurately we can constrain the lepton number asymmetry ξ{sub ν}=μ{sub ν}/T{sub ν} in the Universe by using future observations of 21 cm line fluctuations and cosmic microwave background (CMB). We find that combinations of the 21 cm line and the CMB observations can constrain the lepton asymmetry better than big-bang nucleosynthesis (BBN). Additionally, we also discuss constraints on ξ{sub ν} in the presence of some extra radiation, and show that the 21 cm line observations can substantially improve the constraints obtained by CMB alone, and allow us to distinguish the effects of the lepton asymmetry from the ones of extra radiation.

  6. Longitudinal asymmetries of the coronal line intensities

    NASA Astrophysics Data System (ADS)

    Xanthakis, J.; Petropoulos, B.; Tritakis, V. P.; Mavromichalaki, H.; Marmatsuri, L.

    The analysis of the daily measurements of the coronal green line intensity which have been collected by the Pic-du-Midi Observatory during the period 1944-1974 has led to some very interesting results. The main finding of this analysis is a permanent longitudinal asymmetry of the green line intensity which has been determined all along the data record. In an effort to make this asymmetry certain E-W intensity differences very close to the solar equator where the rotation rate for coronal features is equal to 25.35 days on the average are examined. When these data are examined every 25 days, namely data which almost correspond to the same points of the solar disk, it confirms the above mentioned longitudinal asymmetry.

  7. Bilayer Asymmetry Influences Integrin Sequestering in Raft-Mimicking Lipid Mixtures

    PubMed Central

    Hussain, Noor F.; Siegel, Amanda P.; Ge, Yifan; Jordan, Rainer; Naumann, Christoph A.

    2013-01-01

    There is growing recognition that lipid heterogeneities in cellular membranes play an important role in the distribution and functionality of membrane proteins. However, the detection and characterization of such heterogeneities at the cellular level remains challenging. Here we report on the poorly understood relationship between lipid bilayer asymmetry and membrane protein sequestering in raft-mimicking model membrane mixtures using a powerful experimental platform comprised of confocal spectroscopy XY-scan and photon-counting histogram analyses. This experimental approach is utilized to probe the domain-specific sequestering and oligomerization state of αvβ3 and α5β1 integrins in bilayers, which contain coexisting liquid-disordered/liquid-ordered (ld/lo) phase regions exclusively in the top leaflet of the bilayer (bottom leaflet contains ld phase). Comparison with previously reported integrin sequestering data in bilayer-spanning lo-ld phase separations demonstrates that bilayer asymmetry has a profound influence on αvβ3 and α5β1 sequestering behavior. For example, both integrins sequester preferentially to the lo phase in asymmetric bilayers, but to the ld phase in their symmetric counterparts. Furthermore, our data show that bilayer asymmetry significantly influences the role of native ligands in integrin sequestering. PMID:23708361

  8. Sagittal otolith morphogenesis asymmetry in marine fishes.

    PubMed

    Mille, T; Mahe, K; Villanueva, M C; De Pontual, H; Ernande, B

    2015-09-01

    This study investigated and compared asymmetry in sagittal otolith shape and length between left and right inner ears in four roundfish and four flatfish species of commercial interest. For each species, the effects of ontogenetic changes (individual age and total body length), sexual dimorphism (individual sex) and the otolith's location on the right or left side of the head, on the shape and length of paired otoliths (between 143 and 702 pairs according to species) were evaluated. Ontogenetic changes in otolith shape and length were observed for all species. Sexual dimorphism, either in otolith shape and length or in their ontogenetic changes, was detected for half of the species, be they round or flat. Significant directional asymmetry in otolith shape and length was detected in one roundfish species each, but its inconsistency across species and its small average amplitude (6·17% for shape and 1·99% for length) suggested that it has barely any biological relevance. Significant directional asymmetry in otolith shape and length was found for all flatfish species except otolith length for one species. Its average amplitude varied between 2·06 and 17·50% for shape and between 0·00 and 11·83% for length and increased significantly throughout ontogeny for two species, one dextral and one sinistral. The longer (length) and rounder otolith (shape) appeared to be always on the blind side whatever the species. These results suggest differential biomineralization between the blind and ocular inner ears in flatfish species that could result from perturbations of the proximal-distal gradient of otolith precursors in the endolymph and the otolith position relative to the geometry of the saccular epithelium due to body morphology asymmetry and lateralized behaviour. The fact that asymmetry never exceeded 18% even at the individual level suggests an evolutionary canalization of otolith shape symmetry to avoid negative effects on fish hearing and balance. Technically

  9. Footwear Decreases Gait Asymmetry during Running

    PubMed Central

    Hoerzer, Stefan; Federolf, Peter A.; Maurer, Christian; Baltich, Jennifer; Nigg, Benno M.

    2015-01-01

    Previous research on elderly people has suggested that footwear may improve neuromuscular control of motion. If footwear does in fact improve neuromuscular control, then such an influence might already be present in young, healthy adults. A feature that is often used to assess neuromuscular control of motion is the level of gait asymmetry. The objectives of the study were (a) to develop a comprehensive asymmetry index (CAI) that is capable of detecting gait asymmetry changes caused by external boundary conditions such as footwear, and (b) to use the CAI to investigate whether footwear influences gait asymmetry during running in a healthy, young cohort. Kinematic and kinetic data were collected for both legs of 15 subjects performing five barefoot and five shod over-ground running trials. Thirty continuous gait variables including ground reaction forces and variables of the hip, knee, and ankle joints were computed for each leg. For each individual, the differences between the variables for the right and left leg were calculated. Using this data, a principal component analysis was conducted to obtain the CAI. This study had two main outcomes. First, a sensitivity analysis suggested that the CAI had an improved sensitivity for detecting changes in gait asymmetry caused by external boundary conditions. The CAI may, therefore, have important clinical applications such as monitoring the progress of neuromuscular diseases (e.g. stroke or cerebral palsy). Second, the mean CAI for shod running (131.2 ± 48.5; mean ± standard deviation) was significantly lower (p = 0.041) than the CAI for barefoot running (155.7 ± 39.5). This finding suggests that in healthy, young adults gait asymmetry is reduced when running in shoes compared to running barefoot, which may be a result of improved neuromuscular control caused by changes in the afferent sensory feedback. PMID:26488484

  10. Modelling cellular behaviour

    NASA Astrophysics Data System (ADS)

    Endy, Drew; Brent, Roger

    2001-01-01

    Representations of cellular processes that can be used to compute their future behaviour would be of general scientific and practical value. But past attempts to construct such representations have been disappointing. This is now changing. Increases in biological understanding combined with advances in computational methods and in computer power make it possible to foresee construction of useful and predictive simulations of cellular processes.

  11. Particle-antiparticle asymmetries from annihilations.

    PubMed

    Baldes, Iason; Bell, Nicole F; Petraki, Kalliopi; Volkas, Raymond R

    2014-10-31

    An extensively studied mechanism to create particle-antiparticle asymmetries is the out-of-equilibrium and CP violating decay of a heavy particle. We, instead, examine how asymmetries can arise purely from 2→2 annihilations rather than from the usual 1→2 decays and inverse decays. We review the general conditions on the reaction rates that arise from S-matrix unitarity and CPT invariance, and show how these are implemented in the context of a simple toy model. We formulate the Boltzmann equations for this model, and present an example solution. PMID:25396359

  12. Single hadron transverse spin asymmetries from COMPASS

    SciTech Connect

    Bradamante, Franco

    2007-06-13

    Transverse spin physics is an important part of the scientific programme of the COMPASS experiment at CERN. The analysis of the data taken with the target polarized orthogonally to the 160 GeV/c muon beam momentum has allowed to measure for the first time the Collins and Sivers asymmetries of the deuteron. Both for the positive and the negative hadrons produced in semi-inclusive DIS the measured asymmetries are small and, within errors, compatible with zero. New results for {pi}{+-} ans K{+-} are presented here.

  13. Behavioral evidence for inter-hemispheric cooperation during a lexical decision task: a divided visual field experiment

    PubMed Central

    Perrone-Bertolotti, Marcela; Lemonnier, Sophie; Baciu, Monica

    2013-01-01

    HIGHLIGHTS The redundant bilateral visual presentation of verbal stimuli decreases asymmetry and increases the cooperation between the two hemispheres.The increased cooperation between the hemispheres is related to semantic information during lexical processing.The inter-hemispheric interaction is represented by both inhibition and cooperation. This study explores inter-hemispheric interaction (IHI) during a lexical decision task by using a behavioral approach, the bilateral presentation of stimuli within a divided visual field experiment. Previous studies have shown that compared to unilateral presentation, the bilateral redundant (BR) presentation decreases the inter-hemispheric asymmetry and facilitates the cooperation between hemispheres. However, it is still poorly understood which type of information facilitates this cooperation. In the present study, verbal stimuli were presented unilaterally (left or right visual hemi-field successively) and bilaterally (left and right visual hemi-field simultaneously). Moreover, during the bilateral presentation of stimuli, we manipulated the relationship between target and distractors in order to specify the type of information which modulates the IHI. Thus, three types of information were manipulated: perceptual, semantic, and decisional, respectively named pre-lexical, lexical and post-lexical processing. Our results revealed left hemisphere (LH) lateralization during the lexical decision task. In terms of inter-hemisphere interaction, the perceptual and decision-making information increased the inter-hemispheric asymmetry, suggesting the inhibition of one hemisphere upon the other. In contrast, semantic information decreased the inter-hemispheric asymmetry, suggesting cooperation between the hemispheres. We discussed our results according to current models of IHI and concluded that cerebral hemispheres interact and communicate according to various excitatory and inhibitory mechanisms, all which depend on specific

  14. Rethinking the Digital Divide: Impacts on Student-Tutor Relationships

    ERIC Educational Resources Information Center

    Underwood, Jean D. M.

    2007-01-01

    This article emerged from a series of debates and workshops on the impact of the Digital Divide on educational practice at the "Futures of Learning: New Learning Paradigms Conference" in Paris. The conceptualisation of the Digital Divide into the "haves" and the "have-nots", with a perception of the economically developed world as "high tech" and…

  15. The Digital Divide in Health Education: Myth or Reality?

    ERIC Educational Resources Information Center

    Stellefson, Michael; Chaney, Beth; Chaney, Don

    2008-01-01

    Although e-health interventions provide new opportunities for health education, there has been cause for concern regarding the purported information technology gap between those who have access to digital applications and those who do not--termed the "digital divide." The literature suggests, however, that this divide may now be illusory, driven…

  16. Evaluation of Fatih Project in the Frame of Digital Divide

    ERIC Educational Resources Information Center

    Karabacak, Kerim

    2016-01-01

    The aim of this research realized at the general survey model is to evaluate "FATIH Project" in the frame of digital divide by determining the effects of the distributed tablets to the students being educated at K-12 schools on digital divide. Sample is taking from the 9th grade students in Sakarya city in the 2013-2014 academic session.…

  17. Bridging the Digital Divide--An Australian Story

    ERIC Educational Resources Information Center

    Broadbent, Robyn; Papadopoulos, Theo

    2013-01-01

    There is increasing evidence that the lack of access to information and communication technology (ICT) or the "digital divide" severely limits education, employment and economic prospects. This paper reports on the evaluation of a project that aims to bridge the digital divide. In particular, the case study data has been used to bring to life the…

  18. Distance Education and the Digital Divide: An Academic Perspective

    ERIC Educational Resources Information Center

    Block, Judy

    2010-01-01

    This paper will address how the digital divide affects distance education. Lack of access for some students does raise concerns. Access to technology is often defined by what students don't have: what is called a digital divide. Access also is defined by the speed of Internet connections. Access in the future will be even greater as more computers…

  19. 20 CFR 404.1207 - Divided retirement system coverage groups.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Divided retirement system coverage groups..., SURVIVORS AND DISABILITY INSURANCE (1950- ) Coverage of Employees of State and Local Governments What Groups of Employees May Be Covered § 404.1207 Divided retirement system coverage groups. (a) General....

  20. 37 CFR 2.87 - Dividing an application.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Trademark Trial and Appeal Board. (2) In an application under section 1(b) of the Act, a request to divide... statement of use and the date on which the trademark examining attorney approves the mark for registration... that an international registration has been divided as the result of a change of ownership with...

  1. 37 CFR 2.87 - Dividing an application.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Trademark Trial and Appeal Board. (2) In an application under section 1(b) of the Act, a request to divide... statement of use and the date on which the trademark examining attorney approves the mark for registration... that an international registration has been divided as the result of a change of ownership with...

  2. 37 CFR 2.87 - Dividing an application.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Trademark Trial and Appeal Board. (2) In an application under section 1(b) of the Act, a request to divide... statement of use and the date on which the trademark examining attorney approves the mark for registration... that an international registration has been divided as the result of a change of ownership with...

  3. Technology and the Cultural Divide: A Review of the Literature.

    ERIC Educational Resources Information Center

    Grant, Allen C.

    The recent proliferation of technology in educational settings is giving teachers new and innovative methods of teaching an inquiry-based curriculum within a constructivist framework. One problem within the nation's schools is the growing cultural divide. The cultural divide is the extent of the cultural barrier that exists between educators and…

  4. The Digital Divide and Health Outcomes: A Teleretinal Imaging Study

    ERIC Educational Resources Information Center

    Connolly, Kathleen Kihmm

    2013-01-01

    The purpose of this research project was to understand, explore and describe the digital divide and the relationship between technology utilization and health outcomes. Diabetes and diabetic eye disease was used as the real-life context for understanding change and exploring the digital divide. As an investigational framework, a telemedicine…

  5. X-Band Strip-Line Power Divider/Combiner

    NASA Technical Reports Server (NTRS)

    Conroy, B. L.

    1985-01-01

    Strip-line circuit for X-band signals both divides and combines microwave power for distributed amplifier. Strip-line pattern (foil pattern over insulating layer over ground plane) laid out so all eight distributed ports lie at electrical distances of odd integral multiples of half wavelength from main input/output port. Strip line used as power divider and as power combiner.

  6. Asymmetry and inequity in the inheritance of a bacterial adhesive

    NASA Astrophysics Data System (ADS)

    Cooley, Benjamin J.; Dellos-Nolan, Sheri; Dhamani, Numa; Todd, Ross; Waller, William; Wozniak, Daniel; Gordon, Vernita D.

    2016-04-01

    Pseudomonas aeruginosa is an opportunistic human pathogen that forms biofilm infections in a wide variety of contexts. Biofilms initiate when bacteria attach to a surface, which triggers changes in gene expression leading to the biofilm phenotype. We have previously shown, for the P. aeruginosa lab strain PAO1, that the self-produced polymer Psl is the most dominant adhesive for attachment to the surface but that another self-produced polymer, Pel, controls the geometry of attachment of these rod-shaped bacteria—strains that make Psl but not Pel are permanently attached to the surface but adhere at only one end (tilting up off the surface), whereas wild-type bacteria that make both Psl and Pel are permanently attached and lie down flat with very little or no tilting (Cooley et al 2013 Soft Matter 9 3871–6). Here we show that the change in attachment geometry reflects a change in the distribution of Psl on the bacterial cell surface. Bacteria that make Psl and Pel have Psl evenly coating the surface, whereas bacteria that make only Psl have Psl concentrated at only one end. We show that Psl can act as an inheritable, epigenetic factor. Rod-shaped P. aeruginosa grows lengthwise and divides across the middle. We find that asymmetry in the distribution of Psl on a parent cell is reflected in asymmetry between siblings in their attachment to the surface. Thus, Pel not only promotes P. aeruginosa lying down flat on the surface, it also helps to homogenize the distribution of Psl within a bacterial population.

  7. Three-dimensional multiway power dividers based on transformation optics

    PubMed Central

    Wu, Yong-Le; Zhuang, Zheng; Deng, Li; Liu, Yuan-An

    2016-01-01

    The two-dimensional (2D) or three-dimensional (3D) multiway power dividers based on transformation optical theory are proposed in this paper. It comprises of several nonisotropic mediums and one isotropic medium without any lumped and distributed elements. By using finite embedded coordinate transformations, the incident beam can be split and bent arbitrarily in order to achieve effective power division and transmission. In addition, the location of the split point can be employed to obtain unequal power dividers. Finally, several typical examples of the generalized power divider without limitation in 3D space are performed, which shows that the proposed power divider can implement required functions with arbitrary power division and arbitrary transmission paths. The excellent simulated results verify the novel design method for power dividers. PMID:27091541

  8. Three-dimensional multiway power dividers based on transformation optics

    NASA Astrophysics Data System (ADS)

    Wu, Yong-Le; Zhuang, Zheng; Deng, Li; Liu, Yuan-An

    2016-04-01

    The two-dimensional (2D) or three-dimensional (3D) multiway power dividers based on transformation optical theory are proposed in this paper. It comprises of several nonisotropic mediums and one isotropic medium without any lumped and distributed elements. By using finite embedded coordinate transformations, the incident beam can be split and bent arbitrarily in order to achieve effective power division and transmission. In addition, the location of the split point can be employed to obtain unequal power dividers. Finally, several typical examples of the generalized power divider without limitation in 3D space are performed, which shows that the proposed power divider can implement required functions with arbitrary power division and arbitrary transmission paths. The excellent simulated results verify the novel design method for power dividers.

  9. Three-dimensional multiway power dividers based on transformation optics.

    PubMed

    Wu, Yong-Le; Zhuang, Zheng; Deng, Li; Liu, Yuan-An

    2016-01-01

    The two-dimensional (2D) or three-dimensional (3D) multiway power dividers based on transformation optical theory are proposed in this paper. It comprises of several nonisotropic mediums and one isotropic medium without any lumped and distributed elements. By using finite embedded coordinate transformations, the incident beam can be split and bent arbitrarily in order to achieve effective power division and transmission. In addition, the location of the split point can be employed to obtain unequal power dividers. Finally, several typical examples of the generalized power divider without limitation in 3D space are performed, which shows that the proposed power divider can implement required functions with arbitrary power division and arbitrary transmission paths. The excellent simulated results verify the novel design method for power dividers. PMID:27091541

  10. CP and charge asymmetries at CDF

    SciTech Connect

    Morello, Michael; /Pisa U. /INFN, Pisa

    2007-11-01

    We present CDF results on the branching fractions and time-integrated direct CP asymmetries for B0 and B0s decay modes into pairs of charmless charged hadrons (pions or kaons). We report also the first observation of B0s->DsK mode and the measurement of its branching fraction.

  11. Measuring Asymmetry in Insect-Plant Networks

    NASA Astrophysics Data System (ADS)

    Cruz, Cláudia P. T.; de Almeida, Adriana M.; Corso, Gilberto

    2011-03-01

    In this work we focus on interaction networks between insects and plants and in the characterization of insect plant asymmetry, an important issue in coevolution and evolutionary biology. We analyze in particular the asymmetry in the interaction matrix of animals (herbivorous insects) and plants (food resource for the insects). Instead of driving our attention to the interaction matrix itself we derive two networks associated to the bipartite network: the animal network, D1, and the plant network, D2. These networks are constructed according to the following recipe: two animal species are linked once if they interact with the same plant. In a similar way, in the plant network, two plants are linked if they interact with the same animal. To explore the asymmetry between D2 and D1 we test for a set of 23 networks from the ecologic literature networks: the difference in size, ΔL, clustering coefficient difference, ΔC, and mean connectivity difference, Δ. We used a nonparametric statistical test to check the differences in ΔL, ΔC and Δ. Our results indicate that ΔL and Δ show a significative asymmetry.

  12. Auxin asymmetry during gravitropism by tomato hypocotyls

    NASA Technical Reports Server (NTRS)

    Harrison, M. A.; Pickard, B. G.

    1989-01-01

    Gravitropic asymmetry of auxin was observed in hypocotyls of tomato (Lycopersicon esculentum Mill.) soon after horizontal placement: the ratio of apically supplied [3H]IAA collected from the lower sides to that from the upper sides was about 1.4 between 5 and 10 minutes. This was adequately early to account for the beginning of curvature. The auxin asymmetry ratio rose to about 2.5 between 20 and 25 minutes, and to 3.5 during the main phase of curvature. This compares reasonably well with the roughly 3.9 ratio for elongation on the lower side to elongation on the upper side that is the basis for the curvature. These data extend evidence that the Went-Cholodny theory for the mediation of tropisms is valid for dicot stems. Also consistent with the theory, an auxin asymmetry ratio of 2.5 was observed when wrong-way gravitropic curvature developed following application of a high level of auxin. In addition to reversing the asymmetry of elongation, the large supplement of auxin resulted in lower net elongation. Previous data established that ethylene is not involved in this decrease of growth as a function of increasing level of auxin.

  13. Exploring handedness asymmetries in the Simon effect.

    PubMed

    Seibold, Julia C; Chen, Jing; Proctor, Robert W

    2016-02-01

    Spatially corresponding stimulus-response pairings usually produce shorter reaction times (RTs) than do non-corresponding pairings, even when the spatial dimension of the stimulus is irrelevant to the task. This "Simon effect" for visual stimuli and manual responses is often larger for the stimulus location on the side to which the person's dominant hand is operating. The present study aimed at replicating and examining the nature of this asymmetry. To determine whether the Simon effect asymmetry is a function of the hand distinction or of conceptual spatial codes, performance with left and right manual key-presses was compared to that with vocal responses "left" and "right." Whether the asymmetric Simon effect pattern is restricted to spatial stimuli was tested by comparing effects obtained with left and right located squares to those found with the centered words Left and Right. The asymmetry was only replicated for the spatial stimulus-manual response Simon task, for which a second experiment showed similar results when the hands and response box were not visible during task performance. The analysis revealed a general dominant-hand RT advantage that similarly adds to both corresponding and non-corresponding trials and is rather independent from the Simon effect. This advantage yields an apparent asymmetry when the data are analyzed as a function of correspondence for each stimulus location because the corresponding and non-corresponding RTs that are compared come from different hands. PMID:26676871

  14. Parallel Processing in Visual Search Asymmetry

    ERIC Educational Resources Information Center

    Dosher, Barbara Anne; Han, Songmei; Lu, Zhong-Lin

    2004-01-01

    The difficulty of visual search may depend on assignment of the same visual elements as targets and distractors-search asymmetry. Easy C-in-O searches and difficult O-in-C searches are often associated with parallel and serial search, respectively. Here, the time course of visual search was measured for both tasks with speed-accuracy methods. The…

  15. Neutron contribution to nuclear DVCS asymmetries

    SciTech Connect

    Vadim Guzey

    2008-01-22

    Using a simple model for nuclear GPDs, we study the role of the neutron contribution to nuclear DVCS observables. As an example, we use the beam-spin asymmetry $A_{LU}^A$ measured in coherent and incoherent DVCS on a wide range of nuclear targets in the HERMES and JLab kinematics. We find that at small values of the momentum transfer $t$, $A_{LU}^A$ is dominated by the coherent-enriched contribution, which enhances $A_{LU}^A$ compared to the free proton asymmetry $A_{LU}^p$, $A_{LU}^A(\\phi)/A_{LU}^p(\\phi)=1.8-2.2$. At large values of $t$, the nuclear asymmetry is dominated by the incoherent contribution and $A_{LU}^A/(\\phi)A_{LU}^p(\\phi)=0.66-0.74$. The deviation of $A_{LU}^A(\\phi)/A_{LU}^p(\\phi)$ from unity at large $t$ is a result of the neutron contribution, which gives a possibility to constain neutron GPDs in incoherent nuclear DVCS. A similar trend is expected for other DVCS asymmetries.

  16. Infant Frontal Asymmetry Predicts Child Emotional Availability

    ERIC Educational Resources Information Center

    Licata, Maria; Paulus, Markus; Kühn-Popp, Nina; Meinhardt, Jorg; Sodian, Beate

    2015-01-01

    While factors influencing maternal emotional availability (EA) have been well investigated, little is known about the development of child EA. The present longitudinal study investigated the role of frontal brain asymmetry in young children with regard to child EA (child responsiveness and involvement) in mother-child interaction in a sample of 28…

  17. Search Asymmetry, Sustained Attention, and Response Inhibition

    ERIC Educational Resources Information Center

    Stevenson, Hugh; Russell, Paul N.; Helton, William S.

    2011-01-01

    In the present experiment, we used search asymmetry to test whether the sustained attention to response task is a better measure of response inhibition or sustained attention. Participants performed feature present and feature absent target detection tasks using either a sustained attention to response task (SART; high Go low No-Go) or a…

  18. The Energy of Substituted Ethanes. Asymmetry Orbitals

    PubMed Central

    Salem, Lionel; Hoffmann, Roald; Otto, Peter

    1973-01-01

    The leading terms in the energy of a general substituted ethane are derived in explicit form as a function of the torsional angle θ, the substituent electronegativities, and their mutual overlaps. The energy is found to be the sum of all four overlaps between pairs of asymmetry orbitals, and satisfies the requisite symmetry properties. PMID:16592060

  19. Sources of Local Time Asymmetries in Magnetodiscs

    NASA Astrophysics Data System (ADS)

    Arridge, C. S.; Kane, M.; Sergis, N.; Khurana, K. K.; Jackman, C. M.

    2015-04-01

    The rapidly rotating magnetospheres at Jupiter and Saturn contain a near-equatorial thin current sheet over most local times known as the magnetodisc, resembling a wrapped-up magnetotail. The Pioneer, Voyager, Ulysses, Galileo, Cassini and New Horizons spacecraft at Jupiter and Saturn have provided extensive datasets from which to observationally identify local time asymmetries in these magnetodiscs. Imaging in the infrared and ultraviolet from ground- and space-based instruments have also revealed the presence of local time asymmetries in the aurora which therefore must map to local time asymmetries in the magnetosphere. Asymmetries are found in (i) the configuration of the magnetic field and magnetospheric currents, where a thicker disc is found in the noon and dusk sectors; (ii) plasma flows where the plasma flow has local time-dependent radial components; (iii) a thicker plasma sheet in the dusk sector. Many of these features are also reproduced in global MHD simulations. Several models have been developed to interpret these various observations and typically fall into two groups: ones which invoke coupling with the solar wind (via reconnection or viscous processes) and ones which invoke internal rotational processes operating inside an asymmetrical external boundary. In this paper we review these observational in situ findings, review the models which seek to explain them, and highlight open questions and directions for future work.

  20. Phonological and Phonetic Asymmetries of Cw Combinations

    ERIC Educational Resources Information Center

    Suh, Yunju

    2009-01-01

    This thesis investigates the relationship between the phonological distribution of Cw combinations, and the acoustic/perceptual distinctiveness between syllables with plain C onsets and with Cw combination onsets. Distributional asymmetries of Cw combinations discussed in this thesis include the avoidance of Cw combinations in the labial consonant…

  1. On the nature of the baryon asymmetry

    NASA Technical Reports Server (NTRS)

    Stecker, F. W.

    1984-01-01

    Whether the baryon asymmetry in the universe is a locally varying or universally fixed number is examined with focus on the existence of a possible matter antimatter domain structure in the universe arising from a GUT with spontaneous CP symmetry breaking. Theoretical considerations and observational data and astrophysical tests relating to this fundamental question are reviewed.

  2. 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…

  3. Cellular Reflectarray Antenna

    NASA Technical Reports Server (NTRS)

    Romanofsky, Robert R.

    2010-01-01

    The cellular reflectarray antenna is intended to replace conventional parabolic reflectors that must be physically aligned with a particular satellite in geostationary orbit. These arrays are designed for specified geographical locations, defined by latitude and longitude, each called a "cell." A particular cell occupies nominally 1,500 square miles (3,885 sq. km), but this varies according to latitude and longitude. The cellular reflectarray antenna designed for a particular cell is simply positioned to align with magnetic North, and the antenna surface is level (parallel to the ground). A given cellular reflectarray antenna will not operate in any other cell.

  4. CELLULAR MAGNESIUM HOMEOSTASIS

    PubMed Central

    Romani, Andrea M.P.

    2011-01-01

    Magnesium, the second most abundant cellular cation after potassium, is essential to regulate numerous cellular functions and enzymes, including ion channels, metabolic cycles, and signaling pathways, as attested by more than 1000 entries in the literature. Despite significant recent progress, however, our understanding of how cells regulate Mg2+ homeostasis and transport still remains incomplete. For example, the occurrence of major fluxes of Mg2+ in either direction across the plasma membrane of mammalian cells following metabolic or hormonal stimuli has been extensively documented. Yet, the mechanisms ultimately responsible for magnesium extrusion across the cell membrane have not been cloned. Even less is known about the regulation in cellular organelles. The present review is aimed at providing the reader with a comprehensive and up-to-date understanding of the mechanisms enacted by eukaryotic cells to regulate cellular Mg2+ homeostasis and how these mechanisms are altered under specific pathological conditions. PMID:21640700

  5. Microwave regenerative frequency dividers with low phase noise.

    PubMed

    Ferre-Pikal, E S; Walls, F L

    1999-01-01

    We demonstrate regenerative divide-by-two (halver) circuits with very low phase modulation (PM) noise at input frequencies of 18.4 GHz and 39.8 GHz. The PM noise of the 18.4 to 9.2 GHz divider pair was L(10 Hz)=-134 dB below the carrier in a 1 Hz bandwidth (dBc/Hz) and L(10 MHz)=-166 dBc/Hz, and the PM noise of the 39.8 GHz to 19.9 GHz divider pair was L(10 Hz)=-122 dBc/Hz and L(10 MHz)=-167 dBc/Hz. PMID:18238416

  6. Three-dimensional assessment of facial asymmetry: A systematic review

    PubMed Central

    Akhil, Gopi; Senthil Kumar, Kullampalayam Palanisamy; Raja, Subramani; Janardhanan, Kumaresan

    2015-01-01

    For patients with facial asymmetry, complete and precise diagnosis, and surgical treatments to correct the underlying cause of the asymmetry are significant. Conventional diagnostic radiographs (submento-vertex projections, posteroanterior radiography) have limitations in asymmetry diagnosis due to two-dimensional assessments of three-dimensional (3D) images. The advent of 3D images has greatly reduced the magnification and projection errors that are common in conventional radiographs making it as a precise diagnostic aid for assessment of facial asymmetry. Thus, this article attempts to review the newly introduced 3D tools in the diagnosis of more complex facial asymmetries. PMID:26538893

  7. Alpha Asymmetry in Infants at Risk for Autism Spectrum Disorders

    PubMed Central

    Gabard-Durnam, Laurel; Tierney, Adrienne L.; Vogel-Farley, Vanessa; Tager-Flusberg, Helen; Nelson, Charles A.

    2013-01-01

    An emerging focus of research on autism spectrum disorder (ASD) targets the identification of early-developing ASD endophenotypes using infant siblings of affected children. One potential neural endophenotype is resting frontal electroencephalogram (EEG) alpha asymmetry, a metric of hemispheric organization. Here, we examined the development of frontal EEG alpha asymmetry in ASD high-risk and low-risk infant populations. Our findings demonstrate that low and high-risk infants show different patterns of alpha asymmetry at 6 months of age and opposite growth trajectories in asymmetry over the following 12 months. These results support the candidacy of alpha asymmetry as an early neural ASD endophenotype. PMID:23989937

  8. Narrowing the Digital Divide in Low-Income, Urban Communities

    ERIC Educational Resources Information Center

    Norris, Daniel T.; Conceicao, Simone

    2004-01-01

    The digital divide is leaving millions disenfranchised from the opportunity to use technology to change their lives and to participate fully in democracy, in their own communities, and in today's job market.

  9. Pulse swallowing frequency divider with low power and compact structure

    NASA Astrophysics Data System (ADS)

    Haijun, Gao; Lingling, Sun; Chaobo, Cai; Haiting, Zhan

    2012-11-01

    A pulse swallowing frequency divider with low power and compact structure is presented. One of the DFFs in the divided by 2/3 prescaler is controlled by the modulus control signal, and automatically powered off when it has no contribution to the operation of the prescaler. The DFFs in the program counter and the swallow counter are shared to compose a compact structure, which reduces the power consumption further. The proposed multi-modulus frequency divider was implemented in a standard 65 nm CMOS process with an area of 28 × 22 μm2. The power consumption of the divider is 0.6 mW under 1.2 V supply voltage when operating at 988 MHz.

  10. Unijunction frequency divider is free of backward loading

    NASA Technical Reports Server (NTRS)

    Fairbanks, A. F.

    1965-01-01

    Simple frequency divider composed of relaxation oscillators uses unijunction transistors to reduce backward loading to a minimum. This circuit design is applicable in timing devices and sync generators for television systems.

  11. A 83 GHz InP DHBT static frequency divider

    NASA Astrophysics Data System (ADS)

    Youtao, Zhang; Xiaopeng, Li; Min, Zhang; Wei, Cheng; Xinyu, Chen

    2014-04-01

    A static frequency divider is presented using 0.7 μm InP DHBTs with 280 GHz ft/fmax. The divider is based on ECL master-slave D-flip-flop topology with 30 HBTs and 20 resistors with a chip size 0.62 × 0.65 mm2. The circuits use peaking inductance as a part of the loads to maximize the highest clock rate. Momentum simulation is used to accurately characterize the effect of the clock feedback lines at the W band. Test results show that the divider can operate from 1 GHz up to 83 GHz. Its phase noise is 139 dBc/Hz with 100 kHz offset. The power dissipation of divider core is 350 mW.

  12. Doctors Divided on Safety, Use of Electronic Cigarettes

    MedlinePlus

    ... 160650.html Doctors Divided on Safety, Use of Electronic Cigarettes When patients ask about safety and using ... the best way to answer patients' questions about electronic cigarettes, a new study finds. They also want ...

  13. Geology of photo linear elements, Great Divide Basin, Wyoming

    NASA Technical Reports Server (NTRS)

    Blackstone, D. L., Jr.

    1973-01-01

    The author has identified the following significant results. Ground examination of photo linear elements in the Great Divide Basin, Wyoming indicates little if any tectonic control. Aeolian aspects are more widespread and pervasive than previously considered.

  14. Predictions of the poloidal asymmetries and transport frequencies in KSTAR

    SciTech Connect

    Bae, C. Lee, S. G.; Terzolo, L.; Stacey, W. M.

    2014-01-15

    The extended neoclassical rotation theory formulated in Miller flux surface geometry enables unprecedented neoclassical calculations of the poloidal asymmetries in density, rotation velocities, electrostatic potential along the flux surfaces, and of the inertial (Reynolds stress) and gyroviscous transport frequencies, which are strong functions of these asymmetries. This paper presents such calculations of the poloidal asymmetries and non-negligible inertial and gyroviscous transport frequencies in two KSTAR (Korea Superconducting Tokamak Advanced Research) [Kwon et al., Nucl. Fusion 51, 094006 (2011)] Neutral Beam Injection H-mode discharges. The in-out asymmetries in the velocities are an order of magnitude larger than their up-down asymmetries. The magnitudes of the predicted inertial and gyroviscous transport frequencies depend on the magnitudes of the density and velocity asymmetries. The neoclassically predicted density asymmetries are shown to correspond with the reported measurements in tokamaks and the predicted carbon toroidal velocities agree very well with the measurements in KSTAR.

  15. Possible mechanisms for initiating macroscopic left-right asymmetry in developing organisms

    SciTech Connect

    Henley, Christopher L.

    2009-05-14

    How might systematic left-right (L/R) asymmetry of the body plan originate in multicellular animals (and plants)? Somehow, the microscopic handedness of biological molecules must be brought up to macroscopic scales. Basic symmetry principles suggest that the usual 'biological' mechanisms - diffusion and gene regulation - are insufficient to implement the 'right-hand rule' defining a third body axis from the other two. Instead, on the cellular level, 'physical' mechanisms (forces and collective dynamic states) are needed involving the long stiff fibers of the cytoskeleton. I discuss some possible scenarios; only in the case of vertebrate internal organs is the answer currently known (and even that is in dispute)

  16. Single spin asymmetries in electroproduction at CLAS

    SciTech Connect

    Harut Avakian; Latifa Elouadrhiri

    2004-06-02

    We present measurements of spin asymmetries in semi-inclusive processes in hard scattering kinematics using a 5.7 GeV electron beam and the CEBAF Large Acceptance Spectrometer (CLAS) at JLab. Scattering of longitudinally polarized electrons of an unpolarized liquid-hydrogen and off a polarized NH{sub 3} targets was studied over a wide range of kinematics. Non-zero single-beam and single-target spin asymmetries have been observed in semi-inclusive pion production in hard-scattering kinematics (Q{sup 2} > 1.2 GeV{sup 2}, W{sup 4} > 4 GeV{sup 2}). Systematic studies of factorization of x and z dependences have been done for different spin-dependent and spin-independent observables. No significant x/z dependence has been observed within statistical uncertainties, which is consistent with factorization of hard scattering and fragmentation processes.

  17. QCD evolution of the Sivers asymmetry

    NASA Astrophysics Data System (ADS)

    Echevarria, Miguel G.; Idilbi, Ahmad; Kang, Zhong-Bo; Vitev, Ivan

    2014-04-01

    We study the QCD evolution of the Sivers effect in both semi-inclusive deep inelastic scattering (SIDIS) and Drell-Yan production (DY). We pay close attention to the nonperturbative spin-independent Sudakov factor in the evolution formalism and find a universal form which can describe reasonably well the experimental data on the transverse momentum distributions in SIDIS, DY lepton pair and W/Z production. With this Sudakov factor at hand, we perform a global fitting of all the experimental data on the Sivers asymmetry in SIDIS from HERMES, COMPASS and Jefferson Lab. We then make predictions for the Sivers asymmetry in DY lepton pair and W production that can be compared to the future experimental measurements to test the sign change of the Sivers functions between SIDIS and DY processes and constrain the sea quark Sivers functions.

  18. Scrotal asymmetry, varicocoele and the Riace Bronzes.

    PubMed

    Bonafini, B; Pozzilli, P

    2012-04-01

    In 1972, a pair of remarkably attractive Greek statues, later named Riace Bronzes, were found along the Mediterranean coast in the province of Reggio Calabria, Italy. We analyse the Riace Bronzes in the context of previous research on scrotal asymmetry in Greek statues. By examining their testis, one can define a more exact time of their dating by placing them beside previous observations of scrotal asymmetry, and possibly by taking a pathological condition, varicocoele, as an influencing factor in determining the appearance of the testis. In statue A of the Riace Bronzes, the left testicle is remarkably lower compared with the right one; it also appears as it looks when under physical examination varicocoele is suspected. Being located on the left testicle (as in 90% of cases) and by sight, we feel sufficiently confident to affirm that varicocoele might be diagnosed. PMID:22288773

  19. GDH Integral on the Proton from Asymmetries

    SciTech Connect

    Yelena Prok

    2004-05-01

    Inclusive double spin electron asymmetries have been measured by scattering polarized electrons off the solid polarized {sup 15}NH{sub 3} target in Hall B of Jefferson Lab in 2000-2001. The virtual photon asymmetry A{sub 1} (x), the longitudinal spin structure function, g{sub 1} (x, Q{sup 2}), and the first moment, {Gamma}{sub 1}{sup p}, have been evaluated for a kinematic range of 0.05 {ge} Q{sup 2} {ge} 4.5 GeV{sup 2}. The extracted results complement the existing data in the resonance region, extending it to lower and higher Q{sup 2} regions. The results are important in the study of Q{sup 2} evolution of nucleon structure from the hadronic to partonic degrees of freedom.

  20. Asymmetry Effects in Viscoresistive Magnetic Reconnection

    NASA Astrophysics Data System (ADS)

    Tebaldi, C.; Grasso, D.; Hastie, R. J.

    2010-04-01

    Magnetic reconnection from an asymmetric unreconnected equilibrium is investigated in a viscoresistive plasma via numerical simulations. The instability threshold of the standard stability parameter, Δ', increases with the asymmetry parameter, in a way similar to the effect of increasing viscosity. Also the topology of the velocity field changes significantly, the four-vortex structure typical of the tearing instability evolves into two-vortex structure, with strong increase of the velocity shear across the high magnetic shear rational surface.

  1. Reverse Schottky-asymmetry spin current detectors

    NASA Astrophysics Data System (ADS)

    Lu, Yuan; Appelbaum, Ian

    2010-10-01

    By reversing the Schottky barrier-height asymmetry in hot-electron semiconductor-metal-semiconductor ballistic spin filtering spin detectors, we have achieved the following: (1) demonstration of >50% spin polarization in silicon, resulting from the increase of detection efficiency by elimination of the ferromagnet/silicon interface on the transport channel detector contact and (2) evidence of spin transport at temperatures as high as 260 K, enabled by an increase in detector Schottky barrier height.

  2. Mandibular asymmetry and the fourth dimension.

    PubMed

    Kaban, Leonard B

    2009-03-01

    This paper represents more than 30 years of discussion and collaboration with Drs Joseph Murray and John Mulliken in an attempt to understand growth patterns over time (ie, fourth dimension) in patients with hemifacial microsomia (HFM). This is essential for the development of rational treatment protocols for children and adults with jaw asymmetry. Traditionally, HFM was thought of as a unilateral deformity, but it was recognized that 20% to 30% of patients had bilateral abnormalities. However, early descriptions of skeletal correction addressed almost exclusively lengthening of the short (affected) side of the face. Based on longitudinal clinical observations of unoperated HFM patients, we hypothesized that abnormal mandibular growth is the earliest skeletal manifestation and that restricted growth of the mandible plays a pivotal role in progressive distortion of both the ipsilateral and contralateral facial skeleton. This hypothesis explains the progressive nature of the asymmetry in patients with HFM and provides the rationale for surgical lengthening of the mandible in children to prevent end-stage deformity. During the past 30 years, we have learned that this phenomenon of progressive distortion of the adjacent and contralateral facial skeleton occurs with other asymmetric mandibular undergrowth (tumor resection, radiation therapy, or posttraumatic defects) and overgrowth (mandibular condylar hyperplasia) conditions. In this paper, I describe the progression of deformity with time in patients with mandibular asymmetry as a result of undergrowth and overgrowth. Understanding these concepts is critical for the development of rational treatment protocols for adults with end-stage asymmetry and for children to minimize secondary deformity. PMID:19182686

  3. Cellular Homeostasis and Aging.

    PubMed

    Hartl, F Ulrich

    2016-06-01

    Aging and longevity are controlled by a multiplicity of molecular and cellular signaling events that interface with environmental factors to maintain cellular homeostasis. Modulation of these pathways to extend life span, including insulin-like signaling and the response to dietary restriction, identified the cellular machineries and networks of protein homeostasis (proteostasis) and stress resistance pathways as critical players in the aging process. A decline of proteostasis capacity during aging leads to dysfunction of specific cell types and tissues, rendering the organism susceptible to a range of chronic diseases. This volume of the Annual Review of Biochemistry contains a set of two reviews addressing our current understanding of the molecular mechanisms underlying aging in model organisms and humans. PMID:27050288

  4. Architected Cellular Materials

    NASA Astrophysics Data System (ADS)

    Schaedler, Tobias A.; Carter, William B.

    2016-07-01

    Additive manufacturing enables fabrication of materials with intricate cellular architecture, whereby progress in 3D printing techniques is increasing the possible configurations of voids and solids ad infinitum. Examples are microlattices with graded porosity and truss structures optimized for specific loading conditions. The cellular architecture determines the mechanical properties and density of these materials and can influence a wide range of other properties, e.g., acoustic, thermal, and biological properties. By combining optimized cellular architectures with high-performance metals and ceramics, several lightweight materials that exhibit strength and stiffness previously unachievable at low densities were recently demonstrated. This review introduces the field of architected materials; summarizes the most common fabrication methods, with an emphasis on additive manufacturing; and discusses recent progress in the development of architected materials. The review also discusses important applications, including lightweight structures, energy absorption, metamaterials, thermal management, and bioscaffolds.

  5. Irregular Cellular Learning Automata.

    PubMed

    Esnaashari, Mehdi; Meybodi, Mohammad Reza

    2015-08-01

    Cellular learning automaton (CLA) is a recently introduced model that combines cellular automaton (CA) and learning automaton (LA). The basic idea of CLA is to use LA to adjust the state transition probability of stochastic CA. This model has been used to solve problems in areas such as channel assignment in cellular networks, call admission control, image processing, and very large scale integration placement. In this paper, an extension of CLA called irregular CLA (ICLA) is introduced. This extension is obtained by removing the structure regularity assumption in CLA. Irregularity in the structure of ICLA is needed in some applications, such as computer networks, web mining, and grid computing. The concept of expediency has been introduced for ICLA and then, conditions under which an ICLA becomes expedient are analytically found. PMID:25291810

  6. Neural Correlates of Divided Attention in Natural Scenes.

    PubMed

    Fagioli, Sabrina; Macaluso, Emiliano

    2016-09-01

    Individuals are able to split attention between separate locations, but divided spatial attention incurs the additional requirement of monitoring multiple streams of information. Here, we investigated divided attention using photos of natural scenes, where the rapid categorization of familiar objects and prior knowledge about the likely positions of objects in the real world might affect the interplay between these spatial and nonspatial factors. Sixteen participants underwent fMRI during an object detection task. They were presented with scenes containing either a person or a car, located on the left or right side of the photo. Participants monitored either one or both object categories, in one or both visual hemifields. First, we investigated the interplay between spatial and nonspatial attention by comparing conditions of divided attention between categories and/or locations. We then assessed the contribution of top-down processes versus stimulus-driven signals by separately testing the effects of divided attention in target and nontarget trials. The results revealed activation of a bilateral frontoparietal network when dividing attention between the two object categories versus attending to a single category but no main effect of dividing attention between spatial locations. Within this network, the left dorsal premotor cortex and the left intraparietal sulcus were found to combine task- and stimulus-related signals. These regions showed maximal activation when participants monitored two categories at spatially separate locations and the scene included a nontarget object. We conclude that the dorsal frontoparietal cortex integrates top-down and bottom-up signals in the presence of distractors during divided attention in real-world scenes. PMID:27167404

  7. Inflationary power asymmetry from primordial domain walls

    SciTech Connect

    Jazayeri, Sadra; Akrami, Yashar; Firouzjahi, Hassan; Solomon, Adam R.; Wang, Yi E-mail: yashar.akrami@astro.uio.no E-mail: a.r.solomon@damtp.cam.ac.uk

    2014-11-01

    We study the asymmetric primordial fluctuations in a model of inflation in which translational invariance is broken by a domain wall. We calculate the corrections to the power spectrum of curvature perturbations; they are anisotropic and contain dipole, quadrupole, and higher multipoles with non-trivial scale-dependent amplitudes. Inspired by observations of these multipole asymmetries in terms of two-point correlations and variance in real space, we demonstrate that this model can explain the observed anomalous power asymmetry of the cosmic microwave background (CMB) sky, including its characteristic feature that the dipole dominates over higher multipoles. We test the viability of the model and place approximate constraints on its parameters by using observational values of dipole, quadrupole, and octopole amplitudes of the asymmetry measured by a local-variance estimator. We find that a configuration of the model in which the CMB sphere does not intersect the domain wall during inflation provides a good fit to the data. We further derive analytic expressions for the corrections to the CMB temperature covariance matrix, or angular power spectra, which can be used in future statistical analysis of the model in spherical harmonic space.

  8. Nodal signalling determines biradial asymmetry in Hydra.

    PubMed

    Watanabe, Hiroshi; Schmidt, Heiko A; Kuhn, Anne; Höger, Stefanie K; Kocagöz, Yigit; Laumann-Lipp, Nico; Ozbek, Suat; Holstein, Thomas W

    2014-11-01

    In bilaterians, three orthogonal body axes define the animal form, with distinct anterior-posterior, dorsal-ventral and left-right asymmetries. The key signalling factors are Wnt family proteins for the anterior-posterior axis, Bmp family proteins for the dorsal-ventral axis and Nodal for the left-right axis. Cnidarians, the sister group to bilaterians, are characterized by one oral-aboral body axis, which exhibits a distinct biradiality of unknown molecular nature. Here we analysed the biradial growth pattern in the radially symmetrical cnidarian polyp Hydra, and we report evidence of Nodal in a pre-bilaterian clade. We identified a Nodal-related gene (Ndr) in Hydra magnipapillata, and this gene is essential for setting up an axial asymmetry along the main body axis. This asymmetry defines a lateral signalling centre, inducing a new body axis of a budding polyp orthogonal to the mother polyp's axis. Ndr is expressed exclusively in the lateral bud anlage and induces Pitx, which encodes an evolutionarily conserved transcription factor that functions downstream of Nodal. Reminiscent of its function in vertebrates, Nodal acts downstream of β-Catenin signalling. Our data support an evolutionary scenario in which a 'core-signalling cassette' consisting of β-Catenin, Nodal and Pitx pre-dated the cnidarian-bilaterian split. We presume that this cassette was co-opted for various modes of axial patterning: for example, for lateral branching in cnidarians and left-right patterning in bilaterians. PMID:25156256

  9. Asymmetry-induced electric current rectification in permselective systems

    NASA Astrophysics Data System (ADS)

    Green, Yoav; Edri, Yaron; Yossifon, Gilad

    2015-09-01

    For a symmetric ion permselective system, in terms of geometry and bulk concentrations, the system response is also symmetric under opposite electric field polarity. In this work we derive an analytical solution for the concentration distribution, electric potential, and current-voltage response for a four-layered system comprised of two microchambers connected by two permselective regions of varying properties. It is shown that any additional asymmetry in the system, in terms of the geometry, bulk concentration, or surface charge property of the permselective regions, results in current rectification. Our work is divided into two parts: when both permselective regions have the same surface charge sign and the case of opposite signs. For the same sign case we are able to show that the system behaves as a dialytic battery while accounting for field-focusing effects. For the case of opposite signs (i.e., bipolar membrane), our system exhibits the behavior of a bipolar diode where the magnitude of the rectification can be of order 102-103 .

  10. Observation of the limit cycle in asymmetric plasma divided by a magnetic filter

    NASA Astrophysics Data System (ADS)

    Ohi, Kazuo; Naitou, Hiroshi; Tauchi, Yasushi; Fukumasa, Osamu

    2001-01-01

    An asymmetric plasma divided by a magnetic filter is numerically simulated by the one-dimensional particle-in-cell code VSIM1D [Koga et al., J. Phys. Soc. Jpn. 68, 1578 (1999)]. Depending on the asymmetry, the system behavior is static or dynamic. In the static state, the potentials of the main plasma and the subplasma are given by the sheath potentials, φM˜3TMe/e and φS˜3TSe/e, respectively, with e being an electron charge and TMe and TSe being electron temperatures (TMe>TSe). In the dynamic state, while φM˜3TMe/e, φS oscillates periodically between φS,min˜3TSe/e and φS,max˜3TMe/e. The ions accelerated by the time varying potential gap get into the subplasma and excite the laminar shock waves. The period of the limit cycle is determined by the transit time of the shock wave structure.

  11. The effect of cognitive load on hemispheric asymmetries in true and false memory.

    PubMed

    Tat, Michael J; Azuma, Tamiko

    2016-01-01

    Studies examining hemispheric asymmetries in false memory have shown that the right hemisphere (RH) is more susceptible to false memories compared to the left hemisphere (LH). Theories suggest that hemispheric asymmetries in true and false memory may be due to differences in representational coding and the use of top-down mechanisms in each hemisphere. In the current study, the Deese-Roediger-McDermott false memory paradigm was used in conjunction with divided visual field presentation to examine the role of top-down mechanisms in hemispheric asymmetries of true and false memory. In Experiment 1, participants studied lists of related words while completing secondary cognitive load tasks. In Experiment 2, the secondary tasks were administered during memory retrieval instead of memory encoding. Results revealed that cognitive loads imposed during the study phase influenced veridical memory in the LH more than the RH, but cognitive loads imposed during retrieval did not influence veridical memory in either hemisphere. Surprisingly, false memory rates were not influenced by cognitive loads and were higher in the LH. These data provide evidence that, at least for veridical memory, top-down control mechanisms are used more readily for the encoding of information into memory in the LH compared to the RH. PMID:26291874

  12. Preferential processing of tactile events under conditions of divided attention

    PubMed Central

    Hanson, James V. M.; Whitaker, David; Heron, James

    2012-01-01

    Differences in transduction and transmission latencies of visual, auditory and tactile events cause corresponding differences in simple reaction time. As reaction time is usually measured in unimodal blocks, it is unclear whether such latency differences also apply when observers monitor multiple sensory channels. We investigate this by comparing reaction time when attention is focussed on a single modality, and when attention is divided between multiple modalities. Results show that tactile reaction time is unaffected by dividing attention, whilst visual and auditory reaction times are significantly and asymmetrically increased. These findings show that tactile information is processed preferentially by the nervous system under conditions of divided attention, and suggest that tactile events may be processed pre-attentively. PMID:19738497

  13. Divided loyalties for physicians: social context and moral problems.

    PubMed

    Murray, T H

    1986-01-01

    An examination of the notion of divided loyalties dilemmas in medicine, situated within their social contexts, yields insight into the contemporary social and moral position of medicine in the United States. In a review of the literature, the author identifies four concepts important to gaining an understanding of the position that divided loyalties play in medicine and the physician-patient relationship. After describing some of the situations in which these dilemmas affect physicians' responses to patients' health care needs, interests, and choices, the author argues that divided loyalties dilemmas are not rare, and will probably increase with the changes in U.S. medicine. Candor and awareness of the importance of the public belief in physician loyalty are seen as necessary in preventing these changes from becoming destructive of the physician-patient relationship. PMID:3798163

  14. Dividing Cells Regulate Their Lipid Composition and Localization

    PubMed Central

    Atilla-Gokcumen, G. Ekin; Muro, Eleonora; Relat-Goberna, Josep; Sasse, Sofia; Bedigian, Anne; Coughlin, Margaret L.; Garcia-Manyes, Sergi; Eggert, Ulrike S.

    2014-01-01

    Summary Although massive membrane rearrangements occur during cell division, little is known about specific roles that lipids might play in this process. We report that the lipidome changes with the cell cycle. LC-MS-based lipid profiling shows that 11 lipids with specific chemical structures accumulate in dividing cells. Using AFM, we demonstrate differences in the mechanical properties of live dividing cells and their isolated lipids relative to nondividing cells. In parallel, systematic RNAi knockdown of lipid biosynthetic enzymes identified enzymes required for division, which highly correlated with lipids accumulated in dividing cells. We show that cells specifically regulate the localization of lipids to midbodies, membrane-based structures where cleavage occurs. We conclude that cells actively regulate and modulate their lipid composition and localization during division, with both signaling and structural roles likely. This work has broader implications for the active and sustained participation of lipids in basic biology. PMID:24462247

  15. Genetic Dominance & Cellular Processes

    ERIC Educational Resources Information Center

    Seager, Robert D.

    2014-01-01

    In learning genetics, many students misunderstand and misinterpret what "dominance" means. Understanding is easier if students realize that dominance is not a mechanism, but rather a consequence of underlying cellular processes. For example, metabolic pathways are often little affected by changes in enzyme concentration. This means that…

  16. Teaching cellular engineering.

    PubMed

    Hammer, Daniel A; Waugh, Richard E

    2006-02-01

    Cellular engineering is one of the fastest growing subdisciplines in the field of Biomedical Engineering. It involves the application of engineering analysis to understand and control cellular behavior, with the ultimate objective of developing novel therapeutic or diagnostic approaches for the clinic or harnessing cellular function for commercial applications. Well-educated students in this area need strong foundational knowledge in engineering science, chemistry, and cell and molecular biology. In undergraduate curricula, the challenge is to include essential engineering skills plus appropriate levels of training in chemistry and biology while satisfying accreditation-mandated breadth in engineering training. At the graduate level, educators must accommodate students with diverse backgrounds and provide them with both a state-of-the-art understanding of the life sciences and the most advanced engineering skills. Engineering curricular content should include mechanics and materials, physical chemistry, transport phenomena, and control theory. Training from faculty with appointments and research programs in the life sciences is generally recommended, and additional life science content should also be integrated within the engineering curriculum. A capstone course in cellular engineering that includes opportunities for students to have hands-on experiences with state-of-the-art laboratory techniques is highly recommended. PMID:16450196

  17. Auxin and Cellular Elongation.

    PubMed

    Velasquez, Silvia Melina; Barbez, Elke; Kleine-Vehn, Jürgen; Estevez, José M

    2016-03-01

    Auxin is a crucial growth regulator in plants. However, a comprehensive understanding of how auxin induces cell expansion is perplexing, because auxin acts in a concentration- and cell type-dependent manner. Consequently, it is desirable to focus on certain cell types to exemplify the underlying growth mechanisms. On the other hand, plant tissues display supracellular growth (beyond the level of single cells); hence, other cell types might compromise the growth of a certain tissue. Tip-growing cells do not display neighbor-induced growth constraints and, therefore, are a valuable source of information for growth-controlling mechanisms. Here, we focus on auxin-induced cellular elongation in root hairs, exposing a mechanistic view of plant growth regulation. We highlight a complex interplay between auxin metabolism and transport, steering root hair development in response to internal and external triggers. Auxin signaling modules and downstream cascades of transcription factors define a developmental program that appears rate limiting for cellular growth. With this knowledge in mind, the root hair cell is a very suitable model system in which to dissect cellular effectors required for cellular expansion. PMID:26787325

  18. The New Cellular Immunology

    ERIC Educational Resources Information Center

    Claman, Henry N.

    1973-01-01

    Discusses the nature of the immune response and traces many of the discoveries that have led to the present state of knowledge in immunology. The new cellular immunology is directing its efforts toward improving health by proper manipulation of the immune mechanisms of the body. (JR)

  19. Cortical responses to sustained and divided attention in Alzheimer's disease.

    PubMed

    Johannsen, P; Jakobsen, J; Bruhn, P; Gjedde, A

    1999-09-01

    Neuropsychological data suggests that divided attention is more impaired than sustained attention during the early phases of Alzheimer's disease. The purpose of the present study was to compare cerebral activation patterns during sustained and divided attention between Alzheimer patients and healthy elderly. The O-15-water PET activation method was used to map sustained and divided attention in 16 patients with Alzheimer's disease (mean age +/- SD: 68 +/- 5 years; MMSE: 11-25, mean +/- SD = 19.5 +/- 4.9) and in 16 healthy age-matched control subjects. After stereotactical normalization, voxel-by-voxel t statistics was used to assess the significance of activated brain areas and to compare activations between patients and control subjects. In the healthy elderly, sustained and divided attention both elicited activation of the right inferior parietal lobule, and the right middle frontal gyrus, whereas the anterior cingulate gyrus was activated during sustained attention only. Only medial frontal structures (Brodmann Area (BA) 32/34) were activated in Alzheimer patients, and both frontal (BA-10), posterior cingulate (BA-23/31), and subcortical sites were deactivated. Compared to the healthy elderly, the activations in the patients of the right medial (BA-11) superior (BA-10) and inferior (BA-47) frontal gyri, the right middle temporal (BA-20), and the left lingual (BA-17) gyri were significantly reduced. More cortical sites differed statistically between Alzheimer patients and control subjects during divided than during sustained attention. The activation pattern elicited by attention supports the neuropsychological data that divided attention is more impaired than sustained attention in early Alzheimer's disease. PMID:10458942

  20. Resynchronization in neuronal network divided by femtosecond laser processing.

    PubMed

    Hosokawa, Chie; Kudoh, Suguru N; Kiyohara, Ai; Taguchi, Takahisa

    2008-05-01

    We demonstrated scission of a living neuronal network on multielectrode arrays (MEAs) using a focused femtosecond laser and evaluated the resynchronization of spontaneous electrical activity within the network. By an irradiation of femtosecond laser into hippocampal neurons cultured on a multielectrode array dish, neurites were cut at the focal point. After the irradiation, synchronization of neuronal activity within the network drastically decreased over the divided area, indicating diminished functional connections between neurons. Cross-correlation analysis revealed that spontaneous activity between the divided areas gradually resynchronized within 10 days. These findings indicate that hippocampal neurons have the potential to regenerate functional connections and to reconstruct a network by self-assembly. PMID:18418255

  1. Histological findings of divided muscle after peroral endoscopic myotomy

    PubMed Central

    Shiwaku, Hironari; Inoue, Haruhiro; Nimura, Satoshi; Yamashita, Kanefumi; Ohmiya, Toshihiro; Takeno, Shinsuke; Sasaki, Takamitsu; Yamashita, Yuichi

    2016-01-01

    Peroral endoscopic myotomy (POEM) is a revolutionary therapy for achalasia and related disorders. POEM utilizes almost the same myotomy procedure as the Heller myotomy; thus, it would be expected to have the same or greater duration of therapeutic effect. However, to date, there have been no reports to prove the basis for this procedure in achalasia. In this case, we were able to histologically show the divided muscle after POEM since the patient had an esophagectomy for esophageal cancer. Histology showed that the muscle tissue divided by the POEM procedure was completely replaced by fibrosis. These findings may indirectly show the permanence of the POEM procedure. PMID:26752956

  2. Histological findings of divided muscle after peroral endoscopic myotomy.

    PubMed

    Shiwaku, Hironari; Inoue, Haruhiro; Nimura, Satoshi; Yamashita, Kanefumi; Ohmiya, Toshihiro; Takeno, Shinsuke; Sasaki, Takamitsu; Yamashita, Yuichi

    2016-01-01

    Peroral endoscopic myotomy (POEM) is a revolutionary therapy for achalasia and related disorders. POEM utilizes almost the same myotomy procedure as the Heller myotomy; thus, it would be expected to have the same or greater duration of therapeutic effect. However, to date, there have been no reports to prove the basis for this procedure in achalasia. In this case, we were able to histologically show the divided muscle after POEM since the patient had an esophagectomy for esophageal cancer. Histology showed that the muscle tissue divided by the POEM procedure was completely replaced by fibrosis. These findings may indirectly show the permanence of the POEM procedure. PMID:26752956

  3. Compact waveguide power divider with multiple isolated outputs

    DOEpatents

    Moeller, Charles P.

    1987-01-01

    A waveguide power divider (10) for splitting electromagnetic microwave power and directionally coupling the divided power includes an input waveguide (21) and reduced height output waveguides (23) interconnected by axial slots (22) and matched loads (25) and (26) positioned at the unused ends of input and output guides (21) and (23) respectively. The axial slots are of a length such that the wave in the input waveguide (21) is directionally coupled to the output waveguides (23). The widths of input guide (21) and output guides (23) are equal and the width of axial slots (22) is one half of the width of the input guide (21).

  4. Cellular and Nuclear Alignment Analysis for Determining Epithelial Cell Chirality.

    PubMed

    Raymond, Michael J; Ray, Poulomi; Kaur, Gurleen; Singh, Ajay V; Wan, Leo Q

    2016-05-01

    Left-right (LR) asymmetry is a biologically conserved property in living organisms that can be observed in the asymmetrical arrangement of organs and tissues and in tissue morphogenesis, such as the directional looping of the gastrointestinal tract and heart. The expression of LR asymmetry in embryonic tissues can be appreciated in biased cell alignment. Previously an in vitro chirality assay was reported by patterning multiple cells on microscale defined geometries and quantified the cell phenotype-dependent LR asymmetry, or cell chirality. However, morphology and chirality of individual cells on micropatterned surfaces has not been well characterized. Here, a Python-based algorithm was developed to identify and quantify immunofluorescence stained individual epithelial cells on multicellular patterns. This approach not only produces results similar to the image intensity gradient-based method reported previously, but also can capture properties of single cells such as area and aspect ratio. We also found that cell nuclei exhibited biased alignment. Around 35% cells were misaligned and were typically smaller and less elongated. This new imaging analysis approach is an effective tool for measuring single cell chirality inside multicellular structures and can potentially help unveil biophysical mechanisms underlying cellular chiral bias both in vitro and in vivo. PMID:26294010

  5. Periplasmic Acid Stress Increases Cell Division Asymmetry (Polar Aging) of Escherichia coli

    PubMed Central

    Clark, Michelle W.; Yie, Anna M.; Eder, Elizabeth K.; Dennis, Richard G.; Basting, Preston J.; Martinez, Keith A.; Jones, Brian D.; Slonczewski, Joan L.

    2015-01-01

    Under certain kinds of cytoplasmic stress, Escherichia coli selectively reproduce by distributing the newer cytoplasmic components to new-pole cells while sequestering older, damaged components in cells inheriting the old pole. This phenomenon is termed polar aging or cell division asymmetry. It is unknown whether cell division asymmetry can arise from a periplasmic stress, such as the stress of extracellular acid, which is mediated by the periplasm. We tested the effect of periplasmic acid stress on growth and division of adherent single cells. We tracked individual cell lineages over five or more generations, using fluorescence microscopy with ratiometric pHluorin to measure cytoplasmic pH. Adherent colonies were perfused continually with LBK medium buffered at pH 6.00 or at pH 7.50; the external pH determines periplasmic pH. In each experiment, cell lineages were mapped to correlate division time, pole age and cell generation number. In colonies perfused at pH 6.0, the cells inheriting the oldest pole divided significantly more slowly than the cells inheriting the newest pole. In colonies perfused at pH 7.50 (near or above cytoplasmic pH), no significant cell division asymmetry was observed. Under both conditions (periplasmic pH 6.0 or pH 7.5) the cells maintained cytoplasmic pH values at 7.2–7.3. No evidence of cytoplasmic protein aggregation was seen. Thus, periplasmic acid stress leads to cell division asymmetry with minimal cytoplasmic stress. PMID:26713733

  6. The Digital Divide and Its Impact on Academic Performance

    ERIC Educational Resources Information Center

    Sun, Jerry Chih-Yuan; Metros, Susan E.

    2011-01-01

    The purpose of this article is to explore issues of the digital divide and its impact on academic performance. Research shows that proper use of technology by students increases their academic performance outcomes. In the literature review section, the authors review articles and theories based on Bennett's (2001) societal equity framework. The…

  7. From Fundamentalists to Structuralists: Bridging the Digital Divide

    ERIC Educational Resources Information Center

    Kok, Ayse

    2010-01-01

    The purpose of this literature review is to provide information about several ICT initiatives undertaken in education on a global basis in order to overcome the digital divide and summarise the findings of these initiatives. Due to the limited scope of the study, the bulk of the review mainly concerns initiatives undertaken in secondary schools,…

  8. Digital Divide among Youth: Socio-Cultural Factors and Implications

    ERIC Educational Resources Information Center

    Parycek, Peter; Sachs, Michael; Schossbock, Judith

    2011-01-01

    Purpose: This paper aims to examine socio-cultural differences in internet use (Digital Divide) among 14-year-old Austrian pupils, in particular usage scenarios and research competences. It is based on a paper presented at the International Association for the Development of the Information Society e-Society conference, 10-13 March 2011, Spain…

  9. The Digital Divide: The Special Case of Gender

    ERIC Educational Resources Information Center

    Cooper, J.

    2006-01-01

    This paper examines the evidence for the digital divide based on gender. An overview of research published in the last 20 years draws to the conclusion that females are at a disadvantage relative to men when learning about computers or learning other material with the aid of computer-assisted software. The evidence shows that the digital divide…

  10. New Literacies at the Digital Divide: American Indian Community Computing

    ERIC Educational Resources Information Center

    Betts, J. David

    2009-01-01

    This study is about a community computing lab established by a U.S. Department of Commerce grant to bridge the Digital Divide in a rural Arizona American Indian community, a project called "Native Connection" (a pseudonym). This paper describes the process of integrating new literacies associated with a high-tech computer lab into the life of a…

  11. Peculiarities of the Digital Divide in Sub-Saharan Africa

    ERIC Educational Resources Information Center

    Mutula, Stephen M.

    2005-01-01

    Purpose: Seeks to argue that the peculiarities of sub-Saharan Africa, in terms of its socio-cultural diversity, low economic development, linguistic factors, HIV/AIDS pandemic, gender discrimination, low ICT awareness and so on, demand a new model of addressing the digital divide. Design/methodology/approach: Paper largely based on literature…

  12. A House Divided? The Psychology of Red and Blue America

    ERIC Educational Resources Information Center

    Seyle, D. Conor; Newman, Matthew L.

    2006-01-01

    Recently it has become commonplace in America for commentators and the public to use the terms "red" and "blue" to refer to perceived cultural differences in America and American politics. Although a political divide may exist in America today, these particular terms are inaccurate and reductive. This article presents research from social…

  13. The Digital Divide and Rural Community Colleges: Problems and Prospects.

    ERIC Educational Resources Information Center

    Katsinas, Stephen G.; Moeck, Pat

    2002-01-01

    Discusses the seriousness of the digital divide-the discrepancy between technology-literate and -illiterate people-in rural areas in the United States. Reports that rural young, minority, and single-parent households lag behind the national average in both personal computer ownership and Internet access. Offers suggestions for ways rural community…

  14. Dividing Attention Lowers Children's but Increases Adults' False Memories

    ERIC Educational Resources Information Center

    Otgaar, Henry; Peters, Maarten; Howe, Mark L.

    2012-01-01

    The present study examined the impact of divided attention on children's and adults' neutral and negative true and false memories in a standard Deese/Roediger-McDermott paradigm. Children (7- and 11-year-olds; n = 126) and adults (n = 52) received 5 neutral and 5 negative Deese/Roediger-McDermott word lists; half of each group also received a…

  15. Teachers in the Social Trenches: Teaching Civics in Divided Societies

    ERIC Educational Resources Information Center

    Tamir, Yuli

    2015-01-01

    This article argues that in divided societies, civic education fails to fulfill one of its most important social role: creating a more inclusive society that allows a democratic dialogue to flow across different ideological, religious, and cultural communities. This failure is grounded in two main reasons. First, civics teachers are socially and…

  16. Research and Practice in Education: Building Alliances, Bridging the Divide

    ERIC Educational Resources Information Center

    Coburn, Cynthia E., Ed.; Stein, Mary Kay, Ed.

    2010-01-01

    That there is a divide between research and practice is a common lament across policy-oriented disciplines, and education is no exception. Rhetoric abounds about the role research plays (or does not play) in the improvement of schools and classrooms, and policy makers push solutions that are rooted in assumptions about the way that research…

  17. View looking to the arched entrances that divide the Departmental ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View looking to the arched entrances that divide the Departmental Auditorium from the Interstate Commerce Commission (east) and U.S. Customs Agency (originally Labor Department to the west) - Departmental Auditorium, Constitution Avenue between Twelfth and Fourteenth Streets, Washington, District of Columbia, DC

  18. The Learning Computer: Low Bandwidth Tool that Bridges Digital Divide

    ERIC Educational Resources Information Center

    Johnson, Russell; Kemp, Elizabeth; Kemp, Ray; Blakey, Peter

    2007-01-01

    This article reports on a project that explores strategies for narrowing the digital divide by providing a practicable e-learning option for the millions living outside the ambit of high performance computing and communication technology. The concept is introduced of a "learning computer," a low bandwidth tool that provides a simplified,…

  19. 34 CFR 300.607 - Divided State agency responsibility.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 34 Education 2 2014-07-01 2013-07-01 true Divided State agency responsibility. 300.607 Section 300.607 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION ASSISTANCE TO STATES FOR THE EDUCATION...

  20. 34 CFR 300.607 - Divided State agency responsibility.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 2 2010-07-01 2010-07-01 false Divided State agency responsibility. 300.607 Section 300.607 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION ASSISTANCE TO STATES FOR...

  1. 34 CFR 300.607 - Divided State agency responsibility.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 34 Education 2 2011-07-01 2010-07-01 true Divided State agency responsibility. 300.607 Section 300.607 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION ASSISTANCE TO STATES FOR THE EDUCATION...

  2. 34 CFR 300.607 - Divided State agency responsibility.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 34 Education 2 2012-07-01 2012-07-01 false Divided State agency responsibility. 300.607 Section 300.607 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION ASSISTANCE TO STATES FOR...

  3. 34 CFR 300.607 - Divided State agency responsibility.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 34 Education 2 2013-07-01 2013-07-01 false Divided State agency responsibility. 300.607 Section 300.607 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION ASSISTANCE TO STATES FOR...

  4. Closing the Digital Divide: Evaluation of the World Links Program

    ERIC Educational Resources Information Center

    Kozma, Robert; McGhee, Ray; Quellmalz, Edys; Zalles, Dan

    2004-01-01

    In response to this digital divide between developed and developing countries in their use of computers to prepare students for the global economy, the World Bank and, subsequently, the World Links organization provided schools in developing countries with networked computers and training that supports integration of ICT into teaching. This…

  5. 37 CFR 2.87 - Dividing an application.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... bind the applicant (e.g., a corporate officer or general partner of a partnership), or a practitioner.... (1) When the International Bureau of the World Intellectual Property Organization notifies the Office that an international registration has been divided as the result of a change of ownership with...

  6. Journalism Students, Web 2.0 and the Digital Divide

    ERIC Educational Resources Information Center

    Green, Mary Elizabeth

    2009-01-01

    The purpose of this study was to find out if students were utilizing Web 2.0 applications. Since the applications in question are often employed by the media industry, the study aspired to find out if students majoring in mass communication and journalism utilized the applications more often than other students. The "digital divide" is a term used…

  7. Response Styles and the Rural-Urban Divide

    ERIC Educational Resources Information Center

    Thomas, Troy D.; Abts, Koen; Vander Weyden, Patrick

    2014-01-01

    This article investigates the effect of the rural-urban divide on mean response styles (RSs) and their relationships with the sociodemographic characteristics of the respondents. It uses the Representative Indicator Response Style Means and Covariance Structure (RIRSMACS) method and data from Guyana--a developing country in the Caribbean. The…

  8. Precision high voltage divider for the KATRIN experiment

    NASA Astrophysics Data System (ADS)

    Thümmler, Th; Marx, R.; Weinheimer, Ch

    2009-10-01

    The Karlsruhe Tritium Neutrino (KATRIN) experiment aims to determine the absolute mass of the electron antineutrino from a precise measurement of the tritium β-spectrum near its endpoint at 18.6 keV with a sensitivity of 0.2 eV c-2. KATRIN uses an electrostatic retardation spectrometer of MAC-E filter type for which it is crucial to monitor high voltages of up to 35 kV with a precision and long-term stability at the ppm level. Since devices capable of this precision are not commercially available, a new high voltage divider for direct voltages of up to 35 kV has been designed, following the new concept of the standard divider for direct voltages of up to 100 kV developed at the Physikalisch-Technische Bundesanstalt (PTB)PTB is the German National Metrology Institute providing scientific and technical services.. The electrical and mechanical design of the divider, the screening procedure for the selection of the precision resistors, and the results of the investigation and calibration at the PTB are reported here. During the latter, uncertainties at the low ppm level have been deduced for the new divider, thus qualifying it for the precision measurements of the KATRIN experiment.

  9. Dismantling the Digital Divide: A Multicultural Education Framework.

    ERIC Educational Resources Information Center

    Gorski, Paul C.

    2002-01-01

    Describes inequities in access to computers by gender and race, drawing connections between the two and discussing the use of a multicultural education approach to understanding and eliminating the digital divide. This involves such actions as critiquing technology-related inequities in the context of larger educational and social inequities,…

  10. Middle School Mathematics Students' Justification Schemes for Dividing Fractions

    ERIC Educational Resources Information Center

    Day, Melina Michele

    2010-01-01

    Three theoretical frameworks were used to guide this intervention case study: dividing fractions; sociomathematical norms, and justification. Middle school mathematics students were given the opportunity to solve partitive and measurement division of fraction word problems with different contexts. The teacher purposefully implemented a…

  11. Leadership Analysis in K-12 Case Study: "Divided Loyalties"

    ERIC Educational Resources Information Center

    Alsubaie, Merfat Ayesh

    2016-01-01

    This report mainly aims to provide a critical and in-depth analysis of the K-12 Case, "Divided Loyalty" by Holy and Tartar (2004). The case recounts how the manifestation of inadequate leadership skills in a school setting could affect negatively the performance of students.

  12. ULTRAVIOLET INACTIVATION OF CHLOROPLAST FORMATION IN SYNCHRONOUSLY DIVIDING EUGLENA GRACILIS.

    PubMed

    PETROPULOS, S F

    1964-07-24

    Ultraviolet inactivation of chloroplast formation was studied in synchronously dividing cultures of Euglena gracilis. Sensitivity to sublethal doses given at intervals throughout the cell cycle was greater just before cell division than during division. There was approximately a twofold difference in the doseresponse relationships for the periods of high and low sensitivity. PMID:14172598

  13. The Common Core State Standards and the Great Divide

    ERIC Educational Resources Information Center

    Wiley, Terrence G.; Rolstad, Kellie

    2014-01-01

    This article contextualizes recent developments around issues of language and the new Common Core State Standards (CCSS) in terms of the classic distinction between literates and non-literates in the Great Divide debate. Using a social practices perspective to frame the issues, the authors argue that the CCSS reiterate the debate, and reflect an…

  14. Fabrication of cellular materials

    NASA Astrophysics Data System (ADS)

    Prud'homme, Robert K.; Aksay, Ilhan A.; Garg, Rajeev

    1996-02-01

    Nature uses cellular materials in applications requiring strength while, simultaneously, minimizing raw materials requirements. Minimizing raw materials is efficient both in terms of the energy expended by the organism to synthesize the structure and in terms of the strength- to-weight ratio of the structure. Wood is the most obvious example of cellular bio-materials, and it is the focus of other presentations in this symposium. The lightweight bone structure of birds is another excellent example where weight is a key criterion. The anchoring foot of the common muscle [Mytilus edulis] whereby it attaches itself to objects is a further example of a biological system that uses a foam to fill space and yet conserve on raw materials. In the case of the muscle the foam is water filled and the foot structure distributes stress over a larger area so that the strength of the byssal thread from which it is suspended is matched to the strength of interfacial attachment of the foot to a substrate. In these examples the synthesis and fabrication of the cellular material is directed by intercellular, genetically coded, biochemical reactions. The resulting cell sizes are microns in scale. Cellular materials at the next larger scale are created by organisms at the next higher level of integration. For example an African tree frog lays her eggs in a gas/fluid foam sack she builds on a branch overhanging a pond. The outside of the foam sack hardens in the sun and prevents water evaporation. The foam structure minimizes the amount of fluid that needs to be incorporated into the sack and minimizes its weight. However, as far as the developing eggs are concerned, they are in an aqueous medium, i.e. the continuous fluid phase of the foam. After precisely six days the eggs hatch, and the solidified outer wall re-liquefies and dumps the emerging tadpoles into the pond below. The bee honeycomb is an example of a cellular material with exquisite periodicity at millimeter length scales. The

  15. CPT violation and particle-antiparticle asymmetry in cosmology

    SciTech Connect

    Dolgov, A. D.

    2010-04-15

    General features of generation of the cosmological charge asymmetry in CPT noninvariant world are discussed. If the effects of CPT violationmanifest themselves only inmass differences of particles and antiparticles, the baryon asymmetry of the Universe hardly can be explained solely by breaking of CPT invariance. However, CPT noninvariant theories may lead to a new effect of distorting the usual equilibrium distributions. If this takes place, CPT violation may explain the baryon asymmetry of the Universe.

  16. Advanced on-chip divider for monolithic microwave VCO's

    NASA Technical Reports Server (NTRS)

    Peterson, Weddell C.

    1989-01-01

    High frequency division on a monolithic circuit is a critical technology required to significantly enhance the performance of microwave and millimeter-wave phase-locked sources. The approach used to meet this need is to apply circuit design practices which are essentially 'microwave' in nature to the basically 'digital' problem of high speed division. Following investigation of several promising circuit approaches, program phase 1 culminated in the design and layout of an 8.5 GHz (Deep Space Channel 14) divide by four circuit based on a dynamic mixing divider circuit approach. Therefore, during program phase 2, an 8.5 GHz VCO with an integral divider which provides a phase coherent 2.125 GHz reference signal for phase locking applications was fabricated and optimized. Complete phase locked operation of the monolithic GaAs devices (VCO, power splitter, and dynamic divider) was demonstrated both individually and as an integrated unit. The fully functional integrated unit in a suitable test fixture was delivered to NASA for engineering data correlation. Based on the experience gained from this 8.5 GHz super component, a monolithic GaAs millimeter-wave dynamic divider for operation with an external VCO was also designed, fabricated, and characterized. This circuit, which was also delivered to NASA, demonstrated coherent division by four at an input frequency of 24.3 GHz. The high performance monolithic microwave VCO with a coherent low frequency reference output described in this report and others based on this technology will greatly benefit advanced communications systems in both the DoD and commercial sectors. Signal processing and instrumentation systems based on phase-locking loops will also attain enhanced performance at potentially reduced cost.

  17. Asymmetries in the HD 141569 circumstellar disk

    NASA Astrophysics Data System (ADS)

    Mouillet, D.; Lagrange, A. M.; Augereau, J. C.; Ménard, F.

    2001-06-01

    We present HST/STIS coronagraphic observations of the disk around HD 141569. The data, with a spatial resolution and signal to noise higher than those previously obtained with HST/NICMOS2 allow a more detailed insight in the system. They reveal a very structured system, in which two ring-like structures at distances =~ 200 and 325 AU from the star are the most prominent features. The region between 125 and 175 AU is clearly devoid of material. An arc-like structure is also detected at about 250 AU, as well as a diffuse extended emission, both on the North side of the disk. The system appears to be highly asymmetrical, both with respect to its major and minor axes. Surprisingly, the brightness asymmetry with respect to both axes in the inner and outer parts of the disk is reversed. Possible explanations to the asymmetries include anisotropic scattering and/or non axisymmetrical distribution of the dust within the system. It is shown that anisotropic scattering cannot alone be responsible for all observed asymmetries. It is concluded that HD 141569 disk is non axi-symmetrical. Eventhough no detailed modeling is given in this observational paper, it is probable that the sculpting and brightness properties of the disk are due to the gravitational perturbation of a massive body. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract No. NAS5-26555.

  18. Hemispheric asymmetries of the Venus plasma environment

    NASA Astrophysics Data System (ADS)

    Jarvinen, R.; Kallio, E.; Dyadechkin, S.

    2013-07-01

    We study the Venus-solar wind interaction and the hemispheric asymmetries of the Venus plasma environment in the global HYB-Venus hybrid simulation. We concentrate especially on the role of the flow-aligned interplanetary magnetic field (IMF) component (i.e., the Parker spiral angle or the IMF cone angle) and analyze the dawn-dusk and Esw asymmetries between four magnetic quadrants around Venus. Using the simulation model, we study two upstream condition cases in detail: the perpendicular IMF to the solar wind flow case and the nominal Parker spiral case (dominant flow-aligned IMF component). Several differences and similarities were found in these two simulation runs. Common features of the Venus plasma environment between the two cases include asymmetric magnetic barrier and tail lobes and asymmetric planetary ion escape in the direction of the solar wind convection electric field. Further, protons of planetary origin and of solar wind origin were found to follow similar velocity patterns in the Venus plasma wake in both cases. The differences when the IMF flow-aligned component is dominating compared to the perpendicular IMF case, the so-called (magnetic) dawn-dusk asymmetries, include the parallel bow shock and the foreshock region, the asymmetric magnetic barrier, the asymmetric tail current system, and the asymmetric central tail current sheet. Further, the escaping planetary H+ and O+ ion fluxes are concentrated more on the hemisphere of the parallel bow shock. When interpreting in situ plasma and magnetic observations from Venus, the features of at least these two basic IMF configurations should be considered.

  19. Dividing roles of prion protein in staurosporine-mediated apoptosis.

    PubMed

    Zhang, Ying; Qin, Kefeng; Wang, Jianwei; Hung, Tao; Zhao, Richard Y

    2006-10-20

    Prion protein (PrPC) is a normal cellular glycoprotein that is expressed in almost all tissues including the central nervous system. Much attention has been focused on this protein because conversion of the normal PrPC to the diseased form (PrPSc) plays an essential role in transmissible spongiform encephalopathies such as mad cow disease and Creutzfeldt-Jakob disease. In spite of the extensive effort, the normal physiological function of PrPC remains elusive. Emerging evidence suggests that PrPC plays a protective role against cellular stresses including apoptosis induced by various pro-apoptotic agents such as Bax and staurosporine (STS), however, other reports showed overexpression of PrPC enhances STS-mediated apoptosis. In this study, we took a different approach by depleting endogenous PrPC using specific interfering RNA technique and compared the depleting and overproducing effects of PrPC on STS-induced apoptosis in neuro-2a (N2a) cells. We demonstrate here that down-regulation of PrPC sensitizes N2a cells to STS-induced cytotoxicity and apoptosis. The enhanced apoptosis induced by STS was shown by increased DNA fragmentation, immunoreactivity of Bax, and caspase-3 cleavage. We also showed that overproduction of PrPC had little or no effect on STS-mediated DNA fragmentation in N2a cells but it augments STS-mediated apoptosis in HEK293 cells, suggesting a cell line-specific effect. In addition, the inhibitory effect of PrPC on STS-mediated cellular stress appears to be modulated in part through induction of cell cycle G2 accumulation. Together, our data suggest that physiological level of endogenous PrPC plays a protective role against STS-mediated cellular stress. Loss of this protection could render cells more prone to cellular insults such as STS. PMID:16950206

  20. Cellular growth in biofilms

    SciTech Connect

    Wood, B.D.; Whitaker, S.

    1999-09-20

    In this paper the authors develop a macroscopic evolutionary equation for the growth of the cellular phase starting from a microscopic description of mass transport and a simple structured model for product formation. The methods of continuum mechanics and volume averaging are used to develop the macroscopic representation by carefully considering the fluxes of chemical species that pertain to cell growth. The concept of structured models is extended to include the transport of reacting chemical species at the microscopic scale. The resulting macroscopic growth model is similar in form to previously published models for the transport of a single substrate and electron donor and for the production of cellular mass and exopolymer. The method of volume averaging indicated under what conditions the developed growth model is valid and provides an explicit connection between the relevant microscopic model parameters and their corresponding macroscopic counterparts.

  1. Titan's stratospheric temperature asymmetry: a radiative origin?

    PubMed

    Bézard, B; Coustenis, A; McKay, C P

    1995-02-01

    During the 1981 Voyager encounter, Titan's stratosphere exhibited a large thermal asymmetry, with high northern latitudes being colder than comparable southern latitudes. Given the short radiative time constant, this asymmetry would not be expected at the season of the Voyager observations (spring equinox), if the infrared and solar opacity sources were distributed symmetrically. We have investigated the radiative budget of Titan's stratosphere, using two selections of Voyager IRIS spectra recorded at symmetric northern and southern latitudes. In the region 0.1-1 mbar, temperatures are 7 K colder at 50 degrees N than at 53 degrees S and the difference reaches approximately 13 K at 5 mbar. On the other hand, the northern region is strongly enriched in nitriles and hydrocarbons, and the haze optical depth derived from the continuum emission between 8 and 15 micrometers is twice as large as in the south. Cooling rate profiles have been computed at the two locations, using the gas and haze abundances derived from the IRIS measurements. We find that, despite lower temperatures, the cooling rate profiles in the pressure range 0.15-5 mbar are 20 to 40% larger in the north than in the south, because of the enhanced concentrations of infrared radiators. Because the northern hemisphere appears darker than the southern one in the Voyager images, enhanced solar heating is also expected to take place at 50 degrees N. Solar heating rate profiles have been calculated, with two different assumptions on the origin of the hemispheric asymmetry. In the most likely case where it results from a variation in the absorbance of the haze material, the heating rates are found to be 12-15% larger at the northern location than at the southern one, a smaller increase than that in the cooling rates. If the lower albedo in the north results from an increase in the particle number density, a 55 to 75% difference is found for the pressure range 0.15-5 mbar, thus larger than that calculated for the

  2. Poloidal Asymmetries in Edge Transport Barriers

    NASA Astrophysics Data System (ADS)

    Churchill, R. M.

    2014-10-01

    Investigations of the poloidal structure within edge transport barriers on Alcator C-Mod using novel impurity measurements are presented, revealing large poloidal variations of parameters within a flux surface in the H-mode pedestal region, and significantly reduced poloidal variation in L-mode or I-mode pedestals. These measurements provide complete sets of impurity density, temperature, flow velocity, and electrostatic potential at both the low- and high-field side midplane, utilizing the Gas Puff-CXRS technique. Uncertainties in magnetic equilibrium reconstructions require assumptions to be made in order to properly align the LFS/HFS profiles. In H-mode plasmas, if profiles are aligned assuming impurity temperature is constant on a flux surface, large potential asymmetries would result (eΔΦ /Te ~ 0 . 6). If instead total pressure is assumed constant on a flux-surface, then the measured potential asymmetry is significantly reduced, but large in-out asymmetries result in the impurity temperature (>1.7x). This shows that impurity temperature and potential can not both be flux functions in the pedestal region. In both alignment cases, large asymmetries in impurity density (>6x) are present in H-mode plasmas. In I-mode plasmas, which lack an electron density pedestal but do have a temperature pedestal, the poloidal variation of impurity temperature is weaker (~1.3x) and the impurity density nearly symmetric between the LFS and HFS. These measurements indicate that the sharp gradients in the pedestal region, particularly of main ion density, have a significant effect on the poloidal and radial distribution of impurities, which could have important implications for the prediction of impurity contamination in future fusion reactors such as ITER. Estimates of particle and heat transport timescales suggest that the radial and parallel transport timescales are of the same order in the pedestal region of C-Mod, supporting the idea that two-dimensional transport effects

  3. Top Quark Production Asymmetries AFBt and AFBl

    DOE PAGESBeta

    Berger, Edmond L.; Cao, Qing-Hong; Chen, Chuan-Ren; Yu, Jiang-Hao; Zhang, Hao

    2012-02-14

    A large forward-backward asymmetry is seen in both the top quark rapidity distribution AFBt and in the rapidity distribution of charged leptons AFBl from top quarks produced at the Tevatron. We study the kinematic and dynamic aspects of the relationship of the two observables arising from the spin correlation between the charged lepton and the top quark with different polarization states. We emphasize the value of both measurements, and we conclude that a new physics model which produces more right-handed than left-handed top quarks is favored by the present data.

  4. Charge asymmetry in charmed-meson photoproduction

    SciTech Connect

    Berezhnoy, A. V. Likhoded, A. K.

    2006-01-15

    Within the perturbative-recombination model, the charge asymmetries in the D*{sup +}-D*{sup -}, D*{sup 0}-D*{sup 0}, and D{sup +}{sub s}-D{sup -}{sub s} yields are estimated under the kinematical conditions of the COMPASS experiment. Corrections that arise owing to the mass of a light quark in a charmed meson are taken into account. The yield of D{sup +}{sub s} mesons is predicted to be large in relation to the yield of D{sup -}{sub s} mesons.

  5. Asymmetry in ferroelectric polymer laminate composites

    SciTech Connect

    Newman, B.A.; Scheinbeim, J.I.; Su, Ji

    1996-10-01

    Studies of the ferroelectric and piezoelectric properties of composite bilaminates of poly(vinylidene fluoride) and nylon 11 films have shown that the properties of the bilaminates cannot be understood solely in terms of the properties of the individual components. Further, the properties of films which are polarized with the positive voltage on the nylon 11 side are different from those having the positive voltage on the poly(vinylidene fluoride) side. This asymmetry is interpreted as resulting from a region of space charge trapped at the interface between the two layers.

  6. Scale-dependent CMB asymmetry from primordial configuration

    SciTech Connect

    Kohri, Kazunori; Lin, Chia-Min; Matsuda, Tomohiro E-mail: lin@chuo-u.ac.jp

    2014-08-01

    We demonstrate that a topological defect can explain the hemispherical power asymmetry of the CMB. The first point is that a defect configuration, which already exists prior to inflation, can source asymmetry of the CMB. The second point is that modulation mechanisms, such as the curvaton and other modulation mechanisms, can explain scale-dependence of the asymmetry. Using a simple analysis of the δ N formalism, we show models in which scale-dependent hemispherical power asymmetry is explained by primordial configuration of a defect.

  7. Cellular dysfunction in sepsis.

    PubMed

    Singer, Mervyn

    2008-12-01

    Cellular dysfunction is a commonplace sequelum of sepsis and other systemic inflammatory conditions. Impaired energy production (related to mitochondrial inhibition, damage, and reduced protein turnover) appears to be a core mechanism underlying the development of organ dysfunction. The reduction in energy availability appears to trigger a metabolic shutdown that impairs normal functioning of the cell. This may well represent an adaptive mechanism analogous to hibernation that prevents a massive degree of cell death and thus enables eventual recovery in survivors. PMID:18954700

  8. Radiolabeled cellular blood elements

    SciTech Connect

    Thakur, M.L.; Ezikowitz, M.D.; Hardeman, M.R.

    1985-01-01

    This book contains papers delivered by guest lectures and participants at the Advanced Study Institute's colloquium on Radiolabeled Cellular Blood Elements at Maratea, Italy on August 29, to September 9, 1982. The book includes chapters on basic cell physiology and critical reviews of data and experience in the preparation and use of radiolabeled cells, as well as reports on very recent developments, from a faculty that included experts on cell physiology in health and disease and on the technology of in vivo labeling.

  9. Semantic Asymmetries Are Modulated by Phonological Asymmetries: Evidence from the Disambiguation of Homophonic versus Heterophonic Homographs

    ERIC Educational Resources Information Center

    Peleg, Orna; Eviatar, Zohar

    2009-01-01

    The present study investigated cerebral asymmetries in accessing multiple meanings of two types of homographs: homophonic homographs (e.g., "bank") and heterophonic homographs (e.g., "tear"). Participants read homographs preceded by either a biasing or a non-biasing sentential context and performed a lexical decision on lateralized targets…

  10. Predictability in cellular automata.

    PubMed

    Agapie, Alexandru; Andreica, Anca; Chira, Camelia; Giuclea, Marius

    2014-01-01

    Modelled as finite homogeneous Markov chains, probabilistic cellular automata with local transition probabilities in (0, 1) always posses a stationary distribution. This result alone is not very helpful when it comes to predicting the final configuration; one needs also a formula connecting the probabilities in the stationary distribution to some intrinsic feature of the lattice configuration. Previous results on the asynchronous cellular automata have showed that such feature really exists. It is the number of zero-one borders within the automaton's binary configuration. An exponential formula in the number of zero-one borders has been proved for the 1-D, 2-D and 3-D asynchronous automata with neighborhood three, five and seven, respectively. We perform computer experiments on a synchronous cellular automaton to check whether the empirical distribution obeys also that theoretical formula. The numerical results indicate a perfect fit for neighbourhood three and five, which opens the way for a rigorous proof of the formula in this new, synchronous case. PMID:25271778

  11. Probabilistic cellular automata.

    PubMed

    Agapie, Alexandru; Andreica, Anca; Giuclea, Marius

    2014-09-01

    Cellular automata are binary lattices used for modeling complex dynamical systems. The automaton evolves iteratively from one configuration to another, using some local transition rule based on the number of ones in the neighborhood of each cell. With respect to the number of cells allowed to change per iteration, we speak of either synchronous or asynchronous automata. If randomness is involved to some degree in the transition rule, we speak of probabilistic automata, otherwise they are called deterministic. With either type of cellular automaton we are dealing with, the main theoretical challenge stays the same: starting from an arbitrary initial configuration, predict (with highest accuracy) the end configuration. If the automaton is deterministic, the outcome simplifies to one of two configurations, all zeros or all ones. If the automaton is probabilistic, the whole process is modeled by a finite homogeneous Markov chain, and the outcome is the corresponding stationary distribution. Based on our previous results for the asynchronous case-connecting the probability of a configuration in the stationary distribution to its number of zero-one borders-the article offers both numerical and theoretical insight into the long-term behavior of synchronous cellular automata. PMID:24999557

  12. Quantum cellular automata

    NASA Astrophysics Data System (ADS)

    Porod, Wolfgang; Lent, Craig S.; Bernstein, Gary H.

    1994-06-01

    The Notre Dame group has developed a new paradigm for ultra-dense and ultra-fast information processing in nanoelectronic systems. These Quantum Cellular Automata (QCA's) are the first concrete proposal for a technology based on arrays of coupled quantum dots. The basic building block of these cellular arrays is the Notre Dame Logic Cell, as it has been called in the literature. The phenomenon of Coulomb exclusion, which is a synergistic interplay of quantum confinement and Coulomb interaction, leads to a bistable behavior of each cell which makes possible their use in large-scale cellular arrays. The physical interaction between neighboring cells has been exploited to implement logic functions. New functionality may be achieved in this fashion, and the Notre Dame group invented a versatile majority logic gate. In a series of papers, the feasibility of QCA wires, wire crossing, inverters, and Boolean logic gates was demonstrated. A major finding is that all logic functions may be integrated in a hierarchial fashion which allows the design of complicated QCA structures. The most complicated system which was simulated to date is a one-bit full adder consisting of some 200 cells. In addition to exploring these new concepts, efforts are under way to physically realize such structures both in semiconductor and metal systems. Extensive modeling work of semiconductor quantum dot structures has helped identify optimum design parameters for QCA experimental implementations.

  13. Single transverse spin asymmetry of forward neutrons

    NASA Astrophysics Data System (ADS)

    Kopeliovich, B. Z.; Potashnikova, I. K.; Schmidt, Iván; Soffer, J.

    2011-12-01

    We calculate the single transverse spin asymmetry AN(t), for inclusive neutron production in pp collisions at forward rapidities relative to the polarized proton in the energy range of RHIC. Absorptive corrections to the pion pole generate a relative phase between the spin-flip and nonflip amplitudes, leading to a transverse spin asymmetry which is found to be far too small to explain the magnitude of AN observed in the PHENIX experiment. A larger contribution, which does not vanish at high energies, comes from the interference of pion and a1-Reggeon exchanges. The unnatural parity of a1 guarantees a substantial phase shift, although the magnitude is strongly suppressed by the smallness of diffractive πp→a1p cross section. We replace the Regge a1 pole by the Regge cut corresponding to the πρ exchange in the 1+S state. The production of such a state, which we treat as an effective pole a, forms a narrow peak in the 3π invariant mass distribution in diffractive πp interactions. The cross section is large, so one can assume that this state saturates the spectral function of the axial current and we can determine its coupling to nucleons via the partially conserved axial-vector-current constraint Goldberger-Treiman relation and the second Weinberg sum rule. The numerical results of the parameter-free calculation of AN are in excellent agreement with the PHENIX data.

  14. Cholesterol Asymmetry in Synaptic Plasma Membranes

    PubMed Central

    Wood, W. Gibson; Igbavboa, Urule; Müller, Walter E.; Eckert, Gunter P.

    2010-01-01

    Lipids are essential for the structural and functional integrity of membranes. Membrane lipids are not randomly distributed but are localized in different domains. A common characteristic of these membrane domains is their association with cholesterol. Lipid rafts and caveolae are examples of cholesterol enriched domains, which have attracted keen interest. However, two other important cholesterol domains are the exofacial and cytofacial leaflets of the plasma membrane. The two leaflets that make up the bilayer differ in their fluidity, electrical charge, lipid distribution, and active sites of certain proteins. The synaptic plasma membrane (SPM) cytofacial leaflet contains over 85% of the total SPM cholesterol as compared with the exofacial leaflet. This asymmetric distribution of cholesterol is not fixed or immobile but can be modified by different conditions in vivo: 1) chronic ethanol consumption; 2) statins; 3) aging; and 4) apoE isoform. Several potential candidates have been proposed as mechanisms involved in regulation of SPM cholesterol asymmetry: apoE, low-density-lipoprotein receptor, sterol carrier protein-2, fatty acid binding proteins, polyunsaturated fatty acids, p-glycoprotein and caveolin-1. This review examines cholesterol asymmetry in SPM, potential mechanisms of regulation and impact on membrane structure and function. PMID:21214553

  15. Westward drift, rift asymmetry and continental uplift

    NASA Astrophysics Data System (ADS)

    Doglioni, C.; Carminati, E.; Bonatti, E.

    2003-04-01

    Although not predicted by classic plate tectonics theory, the topography of ocean ridges and rifts show a distinct asymmetry, when depth is plotted both vs. distance from the ridge and square root of the age of the oceanic crust. The eastern sides of the East Pacific Rise, of the mid Atlantic ridge, of the NW Indian ridge are in average more elevated than the conjugate flank to the west and eastern sides show slower subsidence rates. A similar asymmetry can be observed across the Red Sea and Baikal rifts. We suggest that depleted and lighter asthenosphere generated by partial melting below the ocean ridges shifts 'eastward' relative to the lithosphere, determining a density deficit below the eastern flank. The 'eastward' migration of the lighter Atlantic asthenosphere under the African continent, could eventually have contributed to the anomalous post-rift uplift of Africa and explain the anomalously higher topography of Africa with respect to other continents. This model suggests that the 'westward' drift of the lithosphere relative to the underlying mantle might be a global phenomenon and not just a mean delay.

  16. Underlying Asymmetry with Particle-Size Segregation

    NASA Astrophysics Data System (ADS)

    Gajjar, Parmesh; van der Vaart, Kasper; Epely-Chauvin, Gael; Andreini, Nicolas; Gray, Nico; Ancey, Christophe

    2015-11-01

    Granular media have a natural tendency to self-organise when sheared, with different sized constituents counter-intuitively separating from each other. Not only does the segregation produce a rich diversity of beautiful patterns, but it can also have serious implications in both industrial and geophysical environments. Despite the universal importance, the individual particle dynamics during segregation are still poorly understand, with such an analysis proving to be difficult with conventional techniques such as binning and sidewall observation. This talk will present results of recent experiments that studied particle scale segregation dynamics during oscillatory shear. Refractive index matched scanning allowed examination of the interior of the flow, where it was observed that large and small particles have an underlying asymmetry that is dependant on the local particle concentration. Small particles were seen to segregate faster through regions of many large particles, whilst large particles rise slower through regions of many small particles. The asymmetry is quantified on both bulk and particle length scales, and is shown to have good agreement with a continuum model that uses a cubic segregation flux.

  17. CTCF and its protein partners: divide and rule?

    PubMed

    Zlatanova, Jordanka; Caiafa, Paola

    2009-05-01

    CTCF is a ubiquitous transcription factor that is involved in numerous, seemingly unrelated functions. These functions include, but are not limited to, positive or negative regulation of transcription, enhancer-blocking activities at developmentally regulated gene clusters and at imprinted loci, and X-chromosome inactivation. Here, we review recent data acquired with state-of-the-art technologies that illuminate possible mechanisms behind the diversity of CTCF functions. CTCF interacts with numerous protein partners, including cohesin, nucleophosmin, PARP1, Yy1 and RNA polymerase II. We propose that CTCF interacts with one or two different partners according to the biological context, applying the Roman principle of governance, 'divide and rule' (divide et impera). PMID:19386894

  18. Integrated power divider/combiner at hybrid orthogonal junctions

    NASA Astrophysics Data System (ADS)

    El Sherif, Mohamed H.; Ahmed, Osman S.; Bakr, Mohamed H.

    2014-03-01

    We propose an integrated power divider/combiner at the interface between silicon nanowire and plasmonic slot waveguide (PSW). The proposed configuration facilitates light access and manipulation in planar nano-plasmonic circuits. The light is incident from a standard silicon nanowire to be accessed by a nano-plasmonic circuit providing subwavelength confinement. The structure overcomes the losses associated with long distance light propagation in nanoplasmonic splitters as coupling and splitting are performed at the same interface with minimal losses. Two PSWs placed orthogonally to the silicon nanowire forming hybrid junctions are exploited for the power dividing/combining functionality. The power splitter has been analyzed using the finite difference time domain (FDTD) numerical method. The ultra-compact proposed device provides wide-band power splitting functionality. A splitting of 34.7%, over most of the wavelength spectrum from 0.8 μm - 2.5 μm, is demonstrated.

  19. Effects of dividing attention on the memory-block effect.

    PubMed

    Kinoshita, S; Towgood, K

    2001-05-01

    S. M. Smith and D. R. Tindell (1997) reported that prior study of words that are orthographically similar to the solutions of test word fragments (e.g., studying ANALOGY and completing the fragment A_L _ _GY, whose solution is ALLERGY) reduced the fragment completion rate relative to a baseline condition in which unrelated words were studied. They called this effect the memory-block effect. In the present experiment, the authors replicated this effect using a larger set of materials than that used by S. M. Smith and D. R. Tindell. The authors also found that dividing attention at study eliminated the memory-block effect. This pattern mimicked the effect of dividing attention on recognition memory but differed from the effect on repetition priming effects. The authors suggest that the memory-block effect is driven by a mechanism different from that responsible for producing repetition priming effects in an implicit fragment completion test. PMID:11394687

  20. Hybrid songbirds employ intermediate routes in a migratory divide.

    PubMed

    Delmore, Kira E; Irwin, Darren E

    2014-10-01

    Migratory divides are contact zones between populations that use different routes to navigate around unsuitable areas on seasonal migration. Hybrids in divides have been predicted to employ intermediate and potentially inferior routes. We provide the first direct test of this hypothesis, using light-level geolocators to track birds breeding in a hybrid zone between Swainson's thrushes in western Canada. Compared to parental forms, hybrids exhibited increased variability in their migratory routes, with some using intermediate routes that crossed arid and mountainous regions, and some using the same routes as one parental group on fall migration and the other on spring migration. Hybrids also tended to use geographically intermediate wintering sites. Analysis of genetic variation across the hybrid zone suggests moderately strong selection against hybrids. These results indicate that seasonal migratory behaviour might be a source of selection against hybrids, supporting a possible role for migration in speciation. PMID:25040456

  1. Darwinism Then and Now: The Divide Over Form and Function

    NASA Astrophysics Data System (ADS)

    Ruse, Michael

    2010-05-01

    As biologists have recognized since Aristotle, there are two complementary ways of looking at organisms: one can think of them from the viewpoint of homology, asking about the isomorphisms between different organisms and even within the organisms themselves; or one can think of them from the viewpoint of adaptation or final cause, asking about the ends that the features serve. I look at this divide with special respect to the theory of evolution through natural selection as first announced by the English naturalist Charles Darwin in his Origin of Species in 1859, considering both different interpretations that scholars today make of Darwin’s work and the overall implications of Darwin’s achievements for the homology/adaptation, often called the ‘form/function,’ divide.

  2. The cultural divide: exploring communication barriers between scientists and clinicians.

    PubMed

    Restifo, Linda L; Phelan, Gerald R

    2011-07-01

    Despite remarkable advances in basic biomedical science that have led to improved patient care, there is a wide and persistent gap in the abilities of researchers and clinicians to understand and appreciate each other. In this Editorial, the authors, a scientist and a clinician, discuss the rift between practitioners of laboratory research and clinical medicine. Using their first-hand experience and numerous interviews throughout the United States, they explore the causes of this 'cultural divide'. Members of both professions use advanced problem-solving skills and typically embark on their career paths with a deeply felt sense of purpose. Nonetheless, differences in classroom education, professional training environments, reward mechanisms and sources of drive contribute to obstacles that inhibit communication, mutual respect and productive collaboration. More than a sociological curiosity, the cultural divide is a significant barrier to the bench-to-bedside goals of translational medicine. Understanding its roots is the first step towards bridging the gap. PMID:21708897

  3. Fish otolith mass asymmetry: morphometry and influence on acoustic functionality.

    PubMed

    Lychakov, D V; Rebane, Y T

    2005-03-01

    The role of the fish otolith mass asymmetry in acoustic functionality is studied. The saccular, lagenar and utricular otoliths are weighted in two species of the Black Sea rays, 15 species of the Black Sea teleost fish and guppy fish. The dimensionless otolith mass asymmetry chi is calculated as ratio of the difference between masses of the right and left paired otoliths to average otolith mass. In the most fish studied the otolith mass asymmetry is within the range of -0.2 < chi < +0.2 (< 20%). We do not find specific fish species with extremely large or extremely small otolith asymmetry. The large otoliths do not belong solely to any particular side, left or right. The heavier otoliths of different otolithic organs can be located in different labyrinths. No relationship has been found between the magnitude of the otolith mass asymmetry and the length (mass, age) of the animal. The suggested fluctuation model of the otolith growth can interpret these results. The model supposes that the otolith growth rate varies slightly hither and thither during lifetime of the individual fish. Therefore, the sign of the relative otolith mass asymmetry can change several times in the process of the individual fish growth but within the range outlined above. Mathematical modeling shows that acoustic functionality (sensitivity, temporal processing, sound localization) of the fish can be disturbed by the otolith mass asymmetry. But this is valid only for the fish with largest otolith masses, characteristic of the bottom and littoral fish, and with highest otolith asymmetry. For most fish the values of otolith mass asymmetry is well below critical values. Thus, the most fish get around the troubles related to the otolith mass asymmetry. We suggest that a specific physicochemical mechanism of the paired otolith growth that maintains the otolith mass asymmetry at the lowest possible level should exist. However, the principle and details of this mechanism are still far from being

  4. Geothermal resources of the Washakie and Great Divide basins, Wyoming

    SciTech Connect

    Heasler, H.P.; Buelow, K.L.

    1985-01-01

    The geothermal resources of the Great Divide and Washakie Basins of southern Wyoming are described. Oil well bottomhole temperatures, thermal logs of wells, and heat flow data were interpreted within a framework of geologic and hydrologic constraints. It was concluded large areas in Wyoming are underlain by water hotter than 120{sup 0}F. Isolated areas with high temperature gradients exist within each basin. 68 refs., 8 figs., 7 tabs. (ACR)

  5. Unequal-Split Strip-Line Power Divider

    NASA Technical Reports Server (NTRS)

    Bailey, M. C.

    1982-01-01

    Simple technique for designing strip-line or microstrip power dividers can be used for unequal, but inphase power split. Technique allows power splits ranging from equal to as large as required, with advantage of using same line impedances and line spacings for all splits. Output power ratio is determined by selecting location of input port in manner analogous to tap point for electric-power transformer.

  6. Compact high-power microwave divider and combiner.

    PubMed

    Guo, L T; Chang, C; Huang, W H; Liu, Y S; Cao, Y B; Liu, C L; Sun, J

    2016-02-01

    A novel, compact, TM01-TE10 mode power divider and a novel, compact, four-way TE10-TM01 mode power combiner were theoretically designed and experimentally tested as a proof of principle. The theoretical and experimental S parameters are consistent with each other. High-power experiments show that their power capacities are no less than 1.5 GW and 3 GW, respectively. The devices have the merits of high power capacities and low insertion losses. PMID:26931874

  7. Using asymmetry analysis to reduce normal variability of Spectral Domain Optical Coherence Tomography (SD-OCT) macular thickness

    NASA Astrophysics Data System (ADS)

    Alluwimi, Muhammed Saad

    Purpose: To investigate the use of asymmetry analysis to reduce normal between-subject variability of macular thickness measurements using SD-OCT. Methods: 63 volunteers free of eye disease were recruited: 33 young subjects (ages 21 to 35 years with mean and SD of 25 +/- 1.7), and 30 older subjects (ages 45 to 85 years with mean and SD of 66.7 +/- 9.0). All participants passed a comprehensive ophthalmic examination within the past two years. Macular images were gathered with the Spectralis OCT (V 5.4, Heidelberg Engineering, GmbH). The overlay 8x8 grid was manually centered on the fovea and aligned with the foveal-disc axis, then divided into five zones per hemifield following the method of Um et al (2012 IOVS 53:1139); asymmetry was computed as the difference between superior and inferior zone thicknesses. We assumed that the lowest variation and the highest density of ganglion cells will be found ~3° to 6° from the foveal center, corresponding to zones 1 and 2. For each zone and age group, between-subject standard deviations (SDs) were compared for retinal thickness (RT) versus asymmetry using an F-test. To account for repeated measures, a probability of p < 0.0125 was required for statistical significance. Axial length (AL) and corneal curvature (CC) were measured with an IOLMaster by the same operator and during the same imaging session. Results: For OD, asymmetry analysis reduced between-subject variability in zones 1 and 2 in both groups (F > 3.2, p < 0.001). SD for zone 1 dropped from 12.0 to 3.0 mum in the young group and from 11.7 to 2.6 mum in the older group. SD for zone 2 dropped from 13.6 to 5.3 mum (young) and from 11.1 to 5.8 mum (older). Combining all subjects, neither RT nor asymmetry showed a strong correlation with AL or CC (R2 < 0.01). Analysis for OS yielded the same pattern of results, as did asymmetry analyses between eyes (F > 3.8, p < 0.0001). Conclusions: Asymmetry analysis reduced between-subject variability. These findings demonstrate

  8. Comprehensive Analysis of Mandibular Residual Asymmetry after Bilateral Sagittal Split Ramus Osteotomy Correction of Menton Point Deviation

    PubMed Central

    Lin, Qiuping; Huang, Xiaoqiong; Xu, Yue; Yang, Xiaoping

    2016-01-01

    Purpose Facial asymmetry often persists even after mandibular deviation corrected by the bilateral sagittal split ramus osteotomy (BSSRO) operation, since the reference facial sagittal plane for the asymmetry analysis is usually set up before the mandibular menton (Me) point correction. Our aim is to develop a predictive and quantitative method to assess the true asymmetry of the mandible after a midline correction performed by a virtual BSSRO, and to verify its availability by evaluation of the post-surgical improvement. Patients and Methods A retrospective cohort study was conducted at the Hospital of Stomatology, Sun Yat-sen University (China) of patients with pure hemi-mandibular elongation (HE) from September 2010 through May 2014. Mandibular models were reconstructed from CBCT images of patients with pre-surgical orthodontic treatment. After mandibular de-rotation and midline alignment with virtual BSSRO, the elongation hemi-mandible was virtually mirrored along the facial sagittal plane. The residual asymmetry, defined as the superimposition and boolean operation of the mirrored elongation side on the normal side, was calculated, including the volumetric differences and the length of transversal and vertical asymmetry discrepancy. For more specific evaluation, both sides of the hemi-mandible were divided into the symphysis and parasymphysis (SP), mandibular body (MB), and mandibular angle (MA) regions. Other clinical variables include deviation of Me point, dental midline and molar relationship. The measurement of volumetric discrepancy between the two sides of post-surgical hemi-mandible were also calculated to verify the availability of virtual surgery. Paired t-tests were computed and the P value was set at .05. Results This study included 45 patients. The volume differences were 407.8±64.8 mm3, 2139.1±72.5 mm3, and 422.5±36.9 mm3; residual average transversal discrepancy, 1.9 mm, 1.0 mm, and 2.2 mm; average vertical discrepancy, 1.1 mm, 2.2 mm, and 2

  9. How Does a Divided Population Respond to Change?

    PubMed Central

    Qubbaj, Murad R.; Muneepeerakul, Rachata; Aggarwal, Rimjhim M.; Anderies, John M.

    2015-01-01

    Most studies on the response of socioeconomic systems to a sudden shift focus on long-term equilibria or end points. Such narrow focus forgoes many valuable insights. Here we examine the transient dynamics of regime shift on a divided population, exemplified by societies divided ideologically, politically, economically, or technologically. Replicator dynamics is used to investigate the complex transient dynamics of the population response. Though simple, our modeling approach exhibits a surprisingly rich and diverse array of dynamics. Our results highlight the critical roles played by diversity in strategies and the magnitude of the shift. Importantly, it allows for a variety of strategies to arise organically as an integral part of the transient dynamics—as opposed to an independent process—of population response to a regime shift, providing a link between the population's past and future diversity patterns. Several combinations of different populations' strategy distributions and shifts were systematically investigated. Such rich dynamics highlight the challenges of anticipating the response of a divided population to a change. The findings in this paper can potentially improve our understanding of a wide range of socio-ecological and technological transitions. PMID:26161859

  10. Rightward dominance in temporal high-frequency electrical asymmetry corresponds to higher resting heart rate and lower baroreflex sensitivity in a heterogeneous population

    PubMed Central

    Tegeler, Charles H; Shaltout, Hossam A; Tegeler, Catherine L; Gerdes, Lee; Lee, Sung W

    2015-01-01

    Objective Explore potential use of a temporal lobe electrical asymmetry score to discriminate between sympathetic and parasympathetic tendencies in autonomic cardiovascular regulation. Methods 131 individuals (82 women, mean age 43.1, range 13–83) with diverse clinical conditions completed inventories for depressive (CES-D or BDI-II) and insomnia-related (ISI) symptomatology, and underwent five-minute recordings of heart rate and blood pressure, allowing calculation of heart rate variability and baroreflex sensitivity (BRS), followed by one-minute, two-channel, eyes-closed scalp recordings of brain electrical activity. A temporal lobe high-frequency (23–36 Hz) electrical asymmetry score was calculated for each subject by subtracting the average amplitude in the left temporal region from amplitude in the right temporal region, and dividing by the lesser of the two. Results Depressive and insomnia-related symptomatology exceeding clinical threshold levels were reported by 48% and 50% of subjects, respectively. Using a cutoff value of 5% or greater to define temporal high-frequency asymmetry, subjects with leftward compared to rightward asymmetry were more likely to report use of a sedative-hypnotic medication (42% vs. 22%, P = 0.02). Among subjects with asymmetry of 5% or greater to 30% or greater, those with rightward compared to leftward temporal high-frequency asymmetry had higher resting heart rate (≥5% asymmetry, 72.3 vs. 63.8, P = 0.004; ≥10%, 71.5 vs. 63.0, P = 0.01; ≥20%, 72.2 vs. 64.2, P = 0.05; ≥30%, 71.4 vs. 64.6, P = 0.05). Subjects with larger degrees of rightward compared to leftward temporal high-frequency asymmetry had lower baroreflex sensitivity (≥40% asymmetry, 10.6 vs. 16.4, P = 0.03; ≥50% asymmetry, 10.4 vs. 16.7, P = 0.05). Conclusion In a heterogeneous population, individuals with rightward compared to leftward temporal high-frequency electrical asymmetry had higher resting heart rate and lower BRS. Two

  11. Electrodynamic eigenmodes in cellular morphology.

    PubMed

    Cifra, M

    2012-09-01

    Eigenmodes of the spherical and ellipsoidal dielectric electromagnetic resonator have been analysed. The sizes and shape of the resonators have been chosen to represent the shape of the interphase and dividing animal cell. Electromagnetic modes that have shape exactly suitable for positioning of the sufficiently large organelles in cell (centrosome, nucleus) have been identified. We analysed direction and magnitude of dielectrophoretic force exerted on large organelles by electric field of the modes. We found that the TM(1m1) mode in spherical resonator acts by centripetal force which drags the large organelles which have higher permittivity than the cytosol to the center of the cell. TM-kind of mode in the ellipsoidal resonator acts by force on large polarizable organelles in a direction that corresponds to the movement of the centrosomes (also nucleus) observed during the cell division, i.e. to the foci of the ellipsoidal cell. Minimal required force (10(-16) N), gradient of squared electric field and corresponding energy (10(-16) J) of the mode have been calculated to have biological significance within the periods on the order of time required for cell division. Minimal required energy of the mode, in order to have biological significance, can be lower in the case of resonance of organelle with the field of the cellular resonator mode. In case of sufficient energy in the biologically relevant mode, electromagnetic field of the mode will act as a positioning or steering mechanism for centrosome and nucleus in the cell, thus contribute to the spatial and dynamical self-organization in biological systems. PMID:22750075

  12. Formin’ cellular structures

    PubMed Central

    Bogdan, Sven; Schultz, Jörg; Grosshans, Jörg

    2014-01-01

    Members of the Diaphanous (Dia) protein family are key regulators of fundamental actin driven cellular processes, which are conserved from yeast to humans. Researchers have uncovered diverse physiological roles in cell morphology, cell motility, cell polarity, and cell division, which are involved in shaping cells into tissues and organs. The identification of numerous binding partners led to substantial progress in our understanding of the differential functions of Dia proteins. Genetic approaches and new microscopy techniques allow important new insights into their localization, activity, and molecular principles of regulation. PMID:24719676

  13. Control of cellular automata

    NASA Astrophysics Data System (ADS)

    Bagnoli, Franco; Rechtman, Raúl; El Yacoubi, Samira

    2012-12-01

    We study the problem of master-slave synchronization and control of totalistic cellular automata. The synchronization mechanism is that of setting a fraction of sites of the slave system equal to those of the master one (pinching synchronization). The synchronization observable is the distance between the two configurations. We present three control strategies that exploit local information (the number of nonzero first-order Boolean derivatives) in order to choose the sites to be synchronized. When no local information is used, we speak of simple pinching synchronization. We find the critical properties of control and discuss the best control strategy compared with simple synchronization.

  14. Cellular mechanics and motility

    NASA Astrophysics Data System (ADS)

    Hénon, Sylvie; Sykes, Cécile

    2015-10-01

    The term motility defines the movement of a living organism. One widely known example is the motility of sperm cells, or the one of flagellar bacteria. The propulsive element of such organisms is a cilium(or flagellum) that beats. Although cells in our tissues do not have a flagellum in general, they are still able to move, as we will discover in this chapter. In fact, in both cases of movement, with or without a flagellum, cell motility is due to a dynamic re-arrangement of polymers inside the cell. Let us first have a closer look at the propulsion mechanism in the case of a flagellum or a cilium, which is the best known, but also the simplest, and which will help us to define the hydrodynamic general conditions of cell movement. A flagellum is sustained by cellular polymers arranged in semi-flexible bundles and flagellar beating generates cell displacement. These polymers or filaments are part of the cellular skeleton, or "cytoskeleton", which is, in this case, external to the cellular main body of the organism. In fact, bacteria move in a hydrodynamic regime in which viscosity dominates over inertia. The system is thus in a hydrodynamic regime of low Reynolds number (Box 5.1), which is nearly exclusively the case in all cell movements. Bacteria and their propulsion mode by flagella beating are our unicellular ancestors 3.5 billion years ago. Since then, we have evolved to form pluricellular organisms. However, to keep the ability of displacement, to heal our wounds for example, our cells lost their flagellum, since it was not optimal in a dense cell environment: cells are too close to each other to leave enough space for the flagella to accomplish propulsion. The cytoskeleton thus developed inside the cell body to ensure cell shape changes and movement, and also mechanical strength within a tissue. The cytoskeleton of our cells, like the polymers or filaments that sustain the flagellum, is also composed of semi-flexible filaments arranged in bundles, and also in

  15. Understanding jets from sources straddling the Fanaroff-Riley divide

    NASA Astrophysics Data System (ADS)

    Kharb, Preeti; Stanley, Ethan; Lister, Matthew; Marshall, Herman; O'Dea, Chris; Baum, Stefi

    2015-03-01

    Results from Chandra-HST-VLA observations of 13 hybrid sources are presented. Data from ten sources in the literature are analysed along with new data from three hybrid blazars belonging to the MOJAVE sample. Studies of such hybrid sources displaying both FRI and FRII jet characteristics could provide the key to resolving the long-standing Fanaroff-Riley dichotomy issue. A majority of the 13 hybrid sources show FRII-like total radio powers, i.e., they are ``hybrid'' in radio morphology but not in total radio power. VLBI observations of ten of the 13 sources show that the X-ray jet is on the same side as the one-sided VLBI jet. X-rays are therefore emitted from relativistically-boosted approaching jets. This is consistent with the X-ray emission being IC/CMB in origin in the majority of sources. It is not completely clear from our study that asymmetries in the surrounding medium can create hybrid sources. Hybrid radio morphologies could also be indicative of intrinsically asymmetric jets.

  16. Fluctuating Asymmetry and General Intelligence: No Genetic or Phenotypic Association

    ERIC Educational Resources Information Center

    Johnson, Wendy; Segal, Nancy L.; Bouchard, Thomas J., Jr.

    2008-01-01

    Fluctuating asymmetry (FA) is the non-pathological left-right asymmetry of body traits that are usually left-right symmetrical, such as eye breadths and elbow to wrist lengths in humans, but which can be affected by developmental stressors. It is generally considered throughout biology to be an indicator of developmental instability and thus of…

  17. 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.…

  18. Robustness of asymmetry and coherence of quantum states

    NASA Astrophysics Data System (ADS)

    Piani, Marco; Cianciaruso, Marco; Bromley, Thomas R.; Napoli, Carmine; Johnston, Nathaniel; Adesso, Gerardo

    2016-04-01

    Quantum states may exhibit asymmetry with respect to the action of a given group. Such an asymmetry of states can be considered a resource in applications such as quantum metrology, and it is a concept that encompasses quantum coherence as a special case. We introduce explicitly and study the robustness of asymmetry, a quantifier of asymmetry of states that we prove to have many attractive properties, including efficient numerical computability via semidefinite programming and an operational interpretation in a channel discrimination context. We also introduce the notion of asymmetry witnesses, whose measurement in a laboratory detects the presence of asymmetry. We prove that properly constrained asymmetry witnesses provide lower bounds to the robustness of asymmetry, which is shown to be a directly measurable quantity itself. We then focus our attention on coherence witnesses and the robustness of coherence, for which we prove a number of additional results; these include an analysis of its specific relevance in phase discrimination and quantum metrology, an analytical calculation of its value for a relevant class of quantum states, and tight bounds that relate it to another previously defined coherence monotone.

  19. A Hemispheric Asymmetry for the Unconscious Perception of Emotion

    ERIC Educational Resources Information Center

    Smith, Stephen D.; Bulman-Fleming, M. Barbara

    2004-01-01

    Previous research has demonstrated that hemispheric asymmetries for conscious visual perception do not lead to asymmetries for unconscious visual perception. These studies utilized emotionally neutral items as stimuli. The current research utilized both emotionally negative and neutral stimuli to assess hemispheric differences for conscious and…

  20. Effects Of Asymmetry Of NRZ Data Signals On Performance

    NASA Technical Reports Server (NTRS)

    Nguyen, Tien M.

    1992-01-01

    Report presents theoretical analysis of effects of asymmetry in binary non-return-to-zero (NRZ) data signals upon performance of radiotelemetry system. Simple mathematical model predicting overall degradation of bit signal-to-noise ratio of telemetry system derived. Shows degradation increases with asymmetry.

  1. 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…

  2. Asymmetries of Knowledge and Epistemic Change in Social Gaming Interaction

    ERIC Educational Resources Information Center

    Piirainen-Marsh, Arja; Tainio, Liisa

    2014-01-01

    While a growing number of studies investigate the role of knowledge and interactional management of knowledge asymmetries in conversation analysis, the epistemic organization of multilingual and second language interactions is still largely unexplored. This article addresses this issue by investigating how knowledge asymmetries and changing…

  3. Identification of Foot Pathologies Based on Plantar Pressure Asymmetry.

    PubMed

    Wafai, Linah; Zayegh, Aladin; Woulfe, John; Aziz, Syed Mahfuzul; Begg, Rezaul

    2015-01-01

    Foot pathologies can negatively influence foot function, consequently impairing gait during daily activity, and severely impacting an individual's quality of life. These pathologies are often painful and correspond with high or abnormal plantar pressure, which can result in asymmetry in the pressure distribution between the two feet. There is currently no general consensus on the presence of asymmetry in able-bodied gait, and plantar pressure analysis during gait is in dire need of a standardized method to quantify asymmetry. This paper investigates the use of plantar pressure asymmetry for pathological gait diagnosis. The results of this study involving plantar pressure analysis in fifty one participants (31 healthy and 20 with foot pathologies) support the presence of plantar pressure asymmetry in normal gait. A higher level of asymmetry was detected at the majority of the regions in the feet of the pathological population, including statistically significant differences in the plantar pressure asymmetry in two regions of the foot, metatarsophalangeal joint 3 (MPJ3) and the lateral heel. Quantification of plantar pressure asymmetry may prove to be useful for the identification and diagnosis of various foot pathologies. PMID:26295239

  4. Asymmetries for the Visual Expression and Perception of Speech

    ERIC Educational Resources Information Center

    Nicholls, Michael E. R.; Searle, Dara A.

    2006-01-01

    This study explored asymmetries for movement, expression and perception of visual speech. Sixteen dextral models were videoed as they articulated: "bat," "cat," "fat," and "sat." Measurements revealed that the right side of the mouth was opened wider and for a longer period than the left. The asymmetry was accentuated at the beginning and ends of…

  5. Information Asymmetries as Trade Barriers: ISO 9000 Increases International Commerce

    ERIC Educational Resources Information Center

    Potoski, Matthew; Prakash, Aseem

    2009-01-01

    Spatial, cultural, and linguistic barriers create information asymmetries between buyers and sellers that impede international trade. The International Organization for Standardization's ISO 9000 program is designed to reduce these information asymmetries by providing assurance about the product quality of firms that receive its certification.…

  6. Unvail the Mysterious of the Single Spin Asymmetry

    SciTech Connect

    Yuan, Feng

    2010-01-05

    Single transverse-spin asymmetry in high energy hadronic reaction has been greatly investigated from both experiment and theory sides in the last few years. In this talk, I will summarize some recent theoretical developments, which, in my opinion, help to unvail the mysterious of the single spin asymmetry.

  7. On reducing information asymmetry in U.S. health care.

    PubMed

    Mascarenhas, Oswald A J; Kesavan, Ram; Bernacchi, Michael D

    2013-01-01

    Information asymmetry is a significant issue facing the U.S. health care system. In this article, we investigate some methods of reducing this asymmetry. We trace the information asymmetry using the "wicked problem" of the health care distribution system. An information asymmetry reduction method requiring joint responsibilities among health care stakeholders is developed. It is argued that information asymmetry is a contributor to enormous health care inflation. Hence, any reduction in such asymmetry will reduce health care costs. Concepts from both signaling and corrective justice theories are integrated in this article to help reduce the information asymmetry that exists in the U.S. health care system. Getting health care costs in line with other "advanced" nations, is the long-term solution to the wicked problem that currently exists in the U.S. health care system. There is an immediate need for a centralized health care database with adequate provisions for individual privacy. Both processes as well as an outcome-based control system are essential for reducing information asymmetries in the U.S. health care system. PMID:24308415

  8. Identification of Foot Pathologies Based on Plantar Pressure Asymmetry

    PubMed Central

    Wafai, Linah; Zayegh, Aladin; Woulfe, John; Aziz, Syed Mahfuzul; Begg, Rezaul

    2015-01-01

    Foot pathologies can negatively influence foot function, consequently impairing gait during daily activity, and severely impacting an individual’s quality of life. These pathologies are often painful and correspond with high or abnormal plantar pressure, which can result in asymmetry in the pressure distribution between the two feet. There is currently no general consensus on the presence of asymmetry in able-bodied gait, and plantar pressure analysis during gait is in dire need of a standardized method to quantify asymmetry. This paper investigates the use of plantar pressure asymmetry for pathological gait diagnosis. The results of this study involving plantar pressure analysis in fifty one participants (31 healthy and 20 with foot pathologies) support the presence of plantar pressure asymmetry in normal gait. A higher level of asymmetry was detected at the majority of the regions in the feet of the pathological population, including statistically significant differences in the plantar pressure asymmetry in two regions of the foot, metatarsophalangeal joint 3 (MPJ3) and the lateral heel. Quantification of plantar pressure asymmetry may prove to be useful for the identification and diagnosis of various foot pathologies. PMID:26295239

  9. Observations of Wind Asymmetries in Atlantic Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Dougherty, E.; Davis, C. A.

    2014-12-01

    Most major cities are located on coastlines, vulnerable to the direct impacts of tropical cyclones. Therefore, it is critical to understand and improve prediction of these storms in order to make communities more resilient. Though hurricane warning systems have improved in recent years, these warnings are insufficient, because they fail to account for an indication of tropical cyclone wind asymmetry, or the radial extent of maximum winds in different locations within the cyclone. This study explored the wind asymmetry (defined by magnitude and orientation) among 337 Atlantic tropical cyclones from 1988-2012, utilizing the National Hurricane Center's (NHC) Extended Best Track Dataset (EBT) and Statistical Hurricane Intensity Prediction Scheme (SHIPS). Asymmetry was defined as the magnitude of the largest difference in the radius of gale-force wind across opposing quadrants, normalized by the average of the four wind radii. The asymmetry orientation pointed along the axis of maximum asymmetry toward the quadrant with the greater gale radius. Relationships between wind asymmetry and various storm characteristics such as geographical location, storm life cycle, intensity, size, storm motion, and vertical wind shear were examined. The magnitude of asymmetry increased in higher latitudes and along coastlines, particularly in smaller storms. Asymmetry was higher at the beginning of a storm's life, possibly owing to a less well-organized structure, and higher at the end of a storm's life, coinciding with an increase in vertical wind shear and translation speed. Results from this study may allow for improved tropical cyclone forecasts and warnings to help protect seaside communities.

  10. Transverse single-spin asymmetries: Challenges and recent progress

    DOE PAGESBeta

    Metz, Andreas; Pitonyak, Daniel; Schafer, Andreas; Schlegel, Marc; Vogelsang, Werner; Zhou, Jian

    2014-11-25

    In this study, transverse single-spin asymmetries are among the most intriguing observables in hadronic physics. Though such asymmetries were already measured for the first time about four decades ago, their origin is still under debate. Here we consider transverse single-spin asymmetries in semi-inclusive lepton–nucleon scattering, in nucleon–nucleon scattering, and in inclusive lepton–nucleon scattering. It is argued that, according to recent work, the single-spin asymmetries for those three processes may be simultaneously described in perturbative QCD, where the re-scattering of the active partons plays a crucial role. A comparison of single-spin asymmetries in different reactions can also shed light on themore » universality of transverse momentum dependent parton correlation functions. In particular, we discuss what existing data may tell us about the predicted process dependence of the Sivers function.« less

  11. Transverse single-spin asymmetries: Challenges and recent progress

    SciTech Connect

    Metz, Andreas; Pitonyak, Daniel; Schafer, Andreas; Schlegel, Marc; Vogelsang, Werner; Zhou, Jian

    2014-11-25

    In this study, transverse single-spin asymmetries are among the most intriguing observables in hadronic physics. Though such asymmetries were already measured for the first time about four decades ago, their origin is still under debate. Here we consider transverse single-spin asymmetries in semi-inclusive lepton–nucleon scattering, in nucleon–nucleon scattering, and in inclusive lepton–nucleon scattering. It is argued that, according to recent work, the single-spin asymmetries for those three processes may be simultaneously described in perturbative QCD, where the re-scattering of the active partons plays a crucial role. A comparison of single-spin asymmetries in different reactions can also shed light on the universality of transverse momentum dependent parton correlation functions. In particular, we discuss what existing data may tell us about the predicted process dependence of the Sivers function.

  12. Forward-backward asymmetry in top quark-antiquark production

    SciTech Connect

    Abazov, V.M.; Abbott, B.; Acharya, B. S.; Adams, M.; Adams, T.; Alexeev, G. D.; Alkhazov, G.; Alton, A.; Alverson, G.; Alves, G. A.; Aoki, M.; Arov, M.; Askew, A.; Asman, B.; Atramentov, O.; Avila, C.; BackusMayes, J.; Badaud, F.; Bagby, L.; Baldin, B.; Bandurin, D. V.; Banerjee, S.; Barberis, E.; Baringer, P.; Barreto, J.; Bartlett, J. F.; Bassler, U.; Bazterra, V.; Beale, S.; Bean, A.; Begalli, M.; Begel, M.; Belanger-Champagne, C.; Bellantoni, L.; Beri, S. B.; Bernardi, G.; Bernhard, R.; Bertram, I.; Besancon, M.; Beuselinck, R.; Bezzubov, V. A.; Bhat, P. C.; Bhatnagar, V.; Blazey, G.; Blessing, S.; Bloom, K.; Boehnlein, A.; Boline, D.; Boos, E. E.; Borissov, G.; Bose, T.; Brandt, A.; Brandt, O.; Brock, R.; Brooijmans, G.; Bross, A.; Brown, D.; Brown, J.; Bu, X. B.; Buehler, M.; Buescher, V.; Bunichev, V.; Burdin, S.; Burnett, T. H.; Buszello, C. P.; Calpas, B.; Camacho-Perez, E.; Carrasco-Lizarraga, M. A.; Casey, B. C. K.; Castilla-Valdez, H.; Chakrabarti, S.; Chakraborty, D.; Chan, K. M.; Chandra, A.; Chen, G.; Chevalier-Thery, S.; Cho, D. K.; Cho, S. W.; Choi, S.; Choudhary, B.; Cihangir, S.; Claes, D.; Clutter, J.; Cooke, M.; Cooper, W. E.; Corcoran, M.; Couderc, F.; Cousinou, M. -C.; Croc, A.; Cutts, D.; Das, A.; Davies, G.; De, K.; de Jong, S. J.; De La Cruz-Burelo, E.; Deliot, F.; Demarteau, M.; Demina, R.; Denisov, D.; Denisov, S. P.; Desai, S.; Deterre, C.; DeVaughan, K.; Diehl, H. T.; Diesburg, M.; Ding, P. F.; Dominguez, A.; Dorland, T.; Dubey, A.; Dudko, L. V.; Duggan, D.; Duperrin, A.; Dutt, S.; Dyshkant, A.; Eads, M.; Edmunds, D.; Ellison, J.; Elvira, V. D.; Enari, Y.; Evans, H.; Evdokimov, A.; Evdokimov, V. N.; Facini, G.; Ferbel, T.; Fiedler, F.; Filthaut, F.; Fisher, W.; Fisk, H. E.; Fortner, M.; Fox, H.; Fuess, S.; Garcia-Bellido, A.; Gavrilov, V.; Gay, P.; Geng, W.; Gerbaudo, D.; Gerber, C. E.; Gershtein, Y.; Ginther, G.; Golovanov, G.; Goussiou, A.; Grannis, P. D.; Greder, S.; Greenlee, H.; Greenwood, Z. D.; Gregores, E. M.; Grenier, G.; Gris, Ph; Grivaz, J. -F.; Grohsjean, A.; Gruenendahl, S.; Gruenewald, M. W.; Guillemin, T.; Guo, F.; Gutierrez, G.; Gutierrez, P.; Haas, A.; Hagopian, S.; Haley, J.; Han, L.; Harder, K.; Harel, A.; Hauptman, J. M.; Hays, J.; Head, T.; Hebbeker, T.; Hedin, D.; Hegab, H.; Heinson, A. P.; Heintz, U.; Hensel, C.; Heredia-De La Cruz, I.; Herner, K.; Hesketh, G.; Hildreth, M. D.; Hirosky, R.; Hoang, T.; Hobbs, J. D.; Hoeneisen, B.; Hohlfeld, M.; Hubacek, Z.; Huske, N.; Hynek, V.; Iashvili, I.; Ilchenko, Y.; Illingworth, R.; Ito, A. S.; Jabeen, S.; Jaffre, M.; Jamin, D.; Jayasinghe, A.; Jesik, R.; Johns, K.; Johnson, M.; Johnston, D.; Jonckheere, A.; Jonsson, P.; Joshi, J.; Jung, A. W.; Juste, A.; Kaadze, K.; Kajfasz, E.; Karmanov, D.; Kasper, P. A.; Katsanos, I.; Kehoe, R.; Kermiche, S.; Khalatyan, N.; Khanov, A.; Kharchilava, A.; Kharzheev, Y. N.; Kirby, M. H.; Kohli, J. M.; Kozelov, A. V.; Kraus, J.; Kulikov, S.; Kumar, A.; Kupco, A.; Kurca, T.; Kuzmin, V. A.; Kvita, J.; Lammers, S.; Landsberg, G.; Lebrun, P.; Lee, H. S.; Lee, S. W.; Lee, W. M.; Lellouch, J.; Li, L.; Li, Q. Z.; Lietti, S. M.; Lim, J. K.; Lincoln, D.; Linnemann, J.; Lipaev, V. V.; Lipton, R.; Liu, Y.; Liu, Z.; Lobodenko, A.; Lokajicek, M.; de Sa, R. Lopes; Lubatti, H. J.; Luna-Garcia, R.; Lyon, A. L.; Maciel, A. K. A.; Mackin, D.; Madar, R.; Magana-Villalba, R.; Malik, S.; Malyshev, V. L.; Maravin, Y.; Martinez-Ortega, J.; McCarthy, R.; McGivern, C. L.; Meijer, M. M.; Melnitchouk, A.; Menezes, D.; Mercadante, P. G.; Merkin, M.; Meyer, A.; Meyer, J.; Miconi, F.; Mondal, N. K.; Muanza, G. S.; Mulhearn, M.; Nagy, E.; Naimuddin, M.; Narain, M.; Nayyar, R.; Neal, H. A.; Negret, J. P.; Neustroev, P.; Novaes, S. F.; Nunnemann, T.; Obrant, G.; Orbaker, D.; Orduna, J.; Osman, N.; Osta, J.; et. al.

    2011-12-12

    We present a measurement of forward-backward asymmetry in top quark-antiquark production in proton-antiproton collisions in the final state containing a lepton and at least four jets. Using a data set corresponding to an integrated luminosity of 5.4 fb{sup -1}, collected by the D0 experiment at the Fermilab Tevatron Collider, we measure the t{bar t} forward-backward asymmetry to be (9.2 {+-} 3.7)% at the reconstruction level. When corrected for detector acceptance and resolution, the asymmetry is found to be (19.6 {+-} 6.5)%. We also measure a corrected asymmetry based on the lepton from a top quark decay, found to be (15.2 {+-} 4.0)%. The results are compared to predictions based on the next-to-leading-order QCD generator mc@nlo. The sensitivity of the measured and predicted asymmetries to the modeling of gluon radiation is discussed.

  13. Extrapolation technique pitfalls in asymmetry measurements at colliders

    NASA Astrophysics Data System (ADS)

    Colletti, Katrina; Hong, Ziqing; Toback, David; Wilson, Jonathan S.

    2016-09-01

    Asymmetry measurements are common in collider experiments and can sensitively probe particle properties. Typically, data can only be measured in a finite region covered by the detector, so an extrapolation from the visible asymmetry to the inclusive asymmetry is necessary. Often a constant multiplicative factor is advantageous for the extrapolation and this factor can be readily determined using simulation methods. However, there is a potential, avoidable pitfall involved in the determination of this factor when the asymmetry in the simulated data sample is small. We find that to obtain a reliable estimate of the extrapolation factor, the number of simulated events required rises as the inverse square of the simulated asymmetry; this can mean that an unexpectedly large sample size is required when determining the extrapolation factor.

  14. Tidal asymmetry in estuaries with mixed semidiurnal/diurnal tides

    NASA Astrophysics Data System (ADS)

    Nidzieko, Nicholas J.

    2010-08-01

    Tidal asymmetry in estuaries with mixed, mainly semidiurnal tides arises from both the interaction of principal tides and the higher harmonics generated by distortions within the estuary. The duration asymmetry in rise and fall of water level caused by principal tides on the west coast of the continental United States is ebb-dominant, and so the tide entering estuaries is also ebb-dominant, prior to any internal distortions within the estuary. The interaction of higher harmonics with principal constituents either augments or cancels the duration asymmetry in the principal tides. In estuaries where tidal elevation and velocity phase are near quadrature (90° out of phase), the duration asymmetry in tidal elevation leads to asymmetries in tidal current magnitude. Asymmetry can be conveniently quantified in terms of the sample skewness, γ1, the normalized third sample moment about the mean. An analytic approximation to the skewness shows that traditional metrics of asymmetry, namely the ratio of constituent amplitudes and the relative constituent phase difference, arise from calculating the third sample moment. Observations from three California estuaries of different morphologies are presented as an illustration of how skewness can be used to quantify asymmetry in real systems. As in semidiurnal systems, morphology is a good predictor of whether higher harmonics engender ebb-dominance or flood-dominance, however asymmetry imposed by principal tides at the mouth must first be overcome and so there is a spatial evolution in the total asymmetry. Quantifying observations via skewness should be considered in addition to traditional metrics in estuaries with mixed tides.

  15. Facial asymmetry and genetic ancestry in Latin American admixed populations.

    PubMed

    Quinto-Sánchez, Mirsha; Adhikari, Kaustubh; Acuña-Alonzo, Victor; Cintas, Celia; Silva de Cerqueira, Caio Cesar; Ramallo, Virginia; Castillo, Lucia; Farrera, Arodi; Jaramillo, Claudia; Arias, Williams; Fuentes, Macarena; Everardo, Paola; de Avila, Francisco; Gomez-Valdés, Jorge; Hünemeier, Tábita; Gibbon, Shara; Gallo, Carla; Poletti, Giovanni; Rosique, Javier; Bortolini, Maria Cátira; Canizales-Quinteros, Samuel; Rothhammer, Francisco; Bedoya, Gabriel; Ruiz-Linares, Andres; González-José, Rolando

    2015-05-01

    Fluctuating and directional asymmetry are aspects of morphological variation widely used to infer environmental and genetic factors affecting facial phenotypes. However, the genetic basis and environmental determinants of both asymmetry types is far from being completely known. The analysis of facial asymmetries in admixed individuals can be of help to characterize the impact of a genome's heterozygosity on the developmental basis of both fluctuating and directional asymmetries. Here we characterize the association between genetic ancestry and individual asymmetry on a sample of Latin-American admixed populations. To do so, three-dimensional (3D) facial shape attributes were explored on a sample of 4,104 volunteers aged between 18 and 85 years. Individual ancestry and heterozygosity was estimated using more than 730,000 genome-wide markers. Multivariate techniques applied to geometric morphometric data were used to evaluate the magnitude and significance of directional and fluctuating asymmetry (FA), as well as correlations and multiple regressions aimed to estimate the relationship between facial FA scores and heterozygosity and a set of covariates. Results indicate that directional and FA are both significant, the former being the strongest expression of asymmetry in this sample. In addition, our analyses suggest that there are some specific patterns of facial asymmetries characterizing the different ancestry groups. Finally, we find that more heterozygous individuals exhibit lower levels of asymmetry. Our results highlight the importance of including ancestry-admixture estimators, especially when the analyses are aimed to compare levels of asymmetries on groups differing on socioeconomic levels, as a proxy to estimate developmental noise. PMID:25582401

  16. Generic Divide and Conquer Internet-Based Computing

    NASA Technical Reports Server (NTRS)

    Radenski, Atanas; Follen, Gregory J. (Technical Monitor)

    2001-01-01

    The rapid growth of internet-based applications and the proliferation of networking technologies have been transforming traditional commercial application areas as well as computer and computational sciences and engineering. This growth stimulates the exploration of new, internet-oriented software technologies that can open new research and application opportunities not only for the commercial world, but also for the scientific and high -performance computing applications community. The general goal of this research project is to contribute to better understanding of the transition to internet-based high -performance computing and to develop solutions for some of the difficulties of this transition. More specifically, our goal is to design an architecture for generic divide and conquer internet-based computing, to develop a portable implementation of this architecture, to create an example library of high-performance divide-and-conquer computing agents that run on top of this architecture, and to evaluate the performance of these agents. We have been designing an architecture that incorporates a master task-pool server and utilizes satellite computational servers that operate on the Internet in a dynamically changing large configuration of lower-end nodes provided by volunteer contributors. Our designed architecture is intended to be complementary to and accessible from computational grids such as Globus, Legion, and Condor. Grids provide remote access to existing high-end computing resources; in contrast, our goal is to utilize idle processor time of lower-end internet nodes. Our project is focused on a generic divide-and-conquer paradigm and its applications that operate on a loose and ever changing pool of lower-end internet nodes.

  17. Surface Tension and Adsorption without a Dividing Surface.

    PubMed

    Marmur, Abraham

    2015-11-24

    The ingenious concept of a dividing surface of zero thickness that was introduced by Gibbs is the basis of the theory of surface tension and adsorption. However, some fundamental questions, mainly those related to the location of the dividing surface and the proper definition of relative adsorption, have remained open over the years. To avoid these questions, the present paper proposes to analyze an interfacial phase by defining a thermodynamic system of constant, but nonzero thickness. The interfacial phase is analyzed as it really is, namely a nonuniform three-dimensional entity. The current analysis redevelops the equation for calculating surface tension, though with different assumptions. However, the main point in the proposed model is that the thermodynamic interfacial system, due to its fixed thickness, conforms to the requirement of first-order homogeneity of the internal energy. This property is the key that allows using the Gibbs adsorption isotherm. It is also characteristic of the Gibbs dividing surface model, but has not always been discussed with regard to subsequent models. The resulting equation leads to a simple, "natural" expression for the relative adsorption. This expression may be compared with simulations and sophisticated surface concentration measurements, and from which the dependence of interfacial tension on the solution composition can be derived. Finally, it is important to point out that in order to calculate the interfacial tension as well as the relative adsorption from data on the properties of the interfacial phase, there is no need to know its exact thickness, as long as it is bigger than the actual thickness but sufficiently small. PMID:26523466

  18. On the matter-antimatter asymmetry

    NASA Astrophysics Data System (ADS)

    Perkins, W. A.

    2015-08-01

    Although the big bang should have produced equal amounts of matter and antimatter, there is evidence that the universe does not contain significant amounts of antimatter. The usual explanations for this matter-antimatter asymmetry involve finding causes for Sakharov’s three conditions to be satisfied. However, if the composite photon theory is correct, antimatter galaxies should appear to us as dark matter, neither emitting light (that we can detect) or reflecting ordinary light. Thus the presence of antimatter galaxies may be harder to detect than previously thought. The large clumps of dark matter that have been observed by weak gravitation lensing could be clusters of antimatter galaxies. “Dark photons,” that are hypothesized to cause self-interactions between dark matter particles, are identified as antiphotons in the composite photon theory. The possibility of a patchwork universe, that had been previously excluded, is also re-examined.

  19. Z Boson Asymmetry Measurements at the Tevatron

    SciTech Connect

    Quinn, B.

    2014-01-01

    We present measurements of the forward-backward asymmetry (A_fb) in dilepton pair decays of Z bosons produced in ppbar collisions using the full Tevatron dataset. The CDF experiment extracts a value for the effective weak mixing angle parameter sin^{2}\\theta^{l}_{eff} of 0.2315 +/- 0.0010 from the A_fb distribution of dimuon events in 9.2 fb^{-1} of integrated luminosity. From dielectron events in 9.7 fb^{-1} of data, the D0 experiment finds sin^{2}\\theta^{l}_{eff} = 0.23106 +/- 0.00053, the world's most precise measurement of sin^{2}\\theta^{l}_{eff} from hadron colliders and with light quark couplings.

  20. Leptophilic dark matter from the lepton asymmetry.

    PubMed

    Cohen, Timothy; Zurek, Kathryn M

    2010-03-12

    We present a model of weak scale dark matter (DM) where the thermal DM density is set by the lepton asymmetry due to the presence of higher dimension lepton violating operators. In these models there is generically a separation between the annihilation cross section responsible for the relic abundance (through lepton violating operators) and the annihilation cross section that is relevant for the indirect detection of DM (through lepton preserving operators). This implies a perceived boost in the annihilation cross section in the Galaxy today relative to that derived for canonical thermal freeze-out, giving a natural explanation for the observed cosmic ray electron and positron excesses, without resorting to a Sommerfeld enhancement. These models motivate continued searches for DM with apparently nonthermal annihilation cross sections. The DM may also play a role in radiatively generating Majorana neutrino masses. PMID:20366412

  1. Single-Spin Asymmetries at CLAS

    SciTech Connect

    Avakian, Harutyun

    2003-05-01

    Single spin asymmetries (SSA) are crucial tools in the study of the spin structure of hadrons in pion electroproduction, since they are directly related to some hot topics,including transverse polarization distribution functions, fragmentation of polarized quarks and generalized parton distribution functions. At low beam energies, when the virtual photon has a relatively large angle with respect to the initial spin direction, the measured single-target spin-dependent sin φ moment in the cross section for the longitudinally polarized target contain contributions from the target spin components, both longitudinal and transverse with respect to the photon direction.This contribution presents preliminary results from Jefferson Lab's CLAS detector on beam and target SSA in pion azimuthal distributions in one particle inclusive electroproduction in the DIS regime (Q2 > 1GeV 2,W > 2GeV ) off a polarized NH3 target.

  2. Single Spin Asymmetry in Charmonium Production

    NASA Astrophysics Data System (ADS)

    Godbole, Rohini M.; Kaushik, Abhiram; Misra, Anuradha; Rawoot, Vaibhav

    2015-09-01

    We present estimates of single spin asymmetry (SSA) in the electroproduction of taking into account the transverse momentum dependent (TMD) evolution of the gluon Sivers function and using Color Evaporation Model of charmonium production. We estimate SSA for JLab, HERMES, COMPASS and eRHIC energies using recent parameters for the quark Sivers functions which are fitted using an evolution kernel in which the perturbative part is resummed up to next-to-leading logarithms accuracy. We find that these SSAs are much smaller as compared to our first estimates obtained using DGLAP evolution but are comparable to our estimates obtained using TMD evolution where we had used approximate analytical solution of the TMD evolution equation for the purpose.

  3. Single transverse-spin asymmetry in QCD

    NASA Astrophysics Data System (ADS)

    Koike, Yuji

    2014-09-01

    So far large single transverse-spin asymmetries (SSA) have been observed in many high-energy processes such as semi-inclusive deep inelastic scattering and proton-proton collisions. Since the conventional parton model and perturbative QCD can not accomodate such large SSAs, the framework for QCD hard processes had to be extended to understand the mechanism of SSA. In this extended frameworks of QCD, intrinsic transverse momentum of partons and the multi-parton (quark-gluon and pure-gluonic) correlations in the hadrons, which were absent in the conventional framework, play a crucial role to cause SSAs, and well-defined formulation of these effects has been a big challenge for QCD theorists. Study on these effects has greatly promoted our understanding on QCD dynamics and hadron structure. In this talk, I will present an overview on these theoretical activity, emphasizing the important role of the Drell-Yan process.

  4. Dark Atoms: Asymmetry and Direct Detection

    SciTech Connect

    Kaplan, David E.; Krnjaic, Gordan Z.; Rehermann, Keith R.; Wells, Christopher M.

    2011-10-01

    We present a simple UV completion of Atomic Dark Matter (aDM) in which heavy right-handed neutrinos decay to induce both dark and lepton number densities. This model addresses several outstanding cosmological problems: the matter/anti-matter asymmetry, the dark matter abundance, the number of light degrees of freedom in the early universe, and the smoothing of small-scale structure. Additionally, this realization of aDM may reconcile the CoGeNT excess with recently published null results and predicts a signal in the CRESST Oxygen band. We also find that, due to unscreened long-range interactions, the residual un recombined dark ions settle into a diffuse isothermal halo.

  5. Time-reversal asymmetry in financial systems

    NASA Astrophysics Data System (ADS)

    Jiang, X. F.; Chen, T. T.; Zheng, B.

    2013-11-01

    We investigate the large-fluctuation dynamics in financial markets, based on the minute-to-minute and daily data of the Chinese Indices and the German DAX. The dynamic relaxation both before and after the large fluctuations is characterized by a power law, and the exponents p± usually vary with the strength of the large fluctuations. The large-fluctuation dynamics is time-reversal symmetric at the time scale in minutes, while asymmetric at the daily time scale. Careful analysis reveals that the time-reversal asymmetry is mainly induced by external forces. It is also the external forces which drive the financial system to a non-stationary state. Different characteristics of the Chinese and German stock markets are uncovered.

  6. Asymmetries in the Io plasma torus

    NASA Technical Reports Server (NTRS)

    Desch, M. D.; Farrell, W. M.; Kaiser, M. L.

    1994-01-01

    Using Ulysses radio wave data taken during the 1992 Jupiter encounter, we conclude that there are significant large and small spatial scale azimuthal asymmetries at high latitudes in the Io plasma torus. During a period of time near perijove when the spacecraft motion was predominantly in the azimuthal direction and was relatively fixed in both latitude and radial distance, inferred electron densities depart significantly from the common assumption of longitudinal symmetry. Specifically, electron plasma concentrations near 0 deg system III longitude (and 0400 LT) are greater than those near 180 deg (and 0000 LT). Superposed on this large-scale variation are regularly spaced density depletions, 30-50% in magnitude, and having a spatial periodicity of about 17 deg. Some of these depletions may drive various known radio and plasma wave sources by means of large B parallel electric potentials. The observations are compared with recent models and with the in-situ Voyager observations.

  7. Quantifying asymmetry of quantum states using entanglement

    NASA Astrophysics Data System (ADS)

    Toloui, Borzu

    2013-03-01

    For open systems, symmetric dynamics do not always lead to conservation laws. We show that, for a dynamic symmetry associated with a compact Lie group, one can derive new selection rules from entanglement theory. These selection rules apply to both closed and open systems as well as reversible and irreversible time evolutions. Our approach is based on an embedding of the system's Hilbert space into a tensor product of two Hilbert spaces allowing for the symmetric dynamics to be simulated with local operations. The entanglement of the embedded states determines which transformations are forbidden because of the symmetry. In fact, every bipartite entanglement monotone can be used to quantify the asymmetry of the initial states. Moreover, where the dynamics is reversible, each of these monotones becomes a new conserved quantity. This research has been supported by the Institute for Quantum Information Science (IQIS) at the University of Calgary, Alberta Innovates, NSERC, General Dynamics Canada, and MITACS.

  8. Divided-pulse amplification to the joule level.

    PubMed

    Webb, Benjamin; Azim, Ahmad; Bodnar, Nathan; Chini, Michael; Shah, Lawrence; Richardson, Martin

    2016-07-01

    Divided-pulse amplification (DPA) has proven to be a valuable tool in scaling the peak power of diode-pumped ytterbium-doped amplifiers to beyond the single-pulse threshold for parasitic nonlinear effects. DPA enables the amplification of picosecond pulses in solid-state amplifiers with limited bandwidth beyond the single-pulse damage threshold. In this Letter, we demonstrate DPA of picosecond pulses in a flashlamp-pumped Nd:YAG amplifier for the first time, to the best of our knowledge, yielding a combined pulse energy of 167 mJ. PMID:27367113

  9. Transition duct with divided upstream and downstream portions

    SciTech Connect

    McMahan, Kevin Weston; LeBegue, Jeffrey Scott; Maldonado, Jaime Javier; Dillard, Daniel Jackson; Flanagan, James Scott

    2015-07-14

    Turbine systems are provided. In one embodiment, a turbine system includes a transition duct comprising an inlet, an outlet, and a duct passage extending between the inlet and the outlet and defining a longitudinal axis, a radial axis, and a tangential axis. The outlet of the transition duct is offset from the inlet along the longitudinal axis and the tangential axis. The duct passage includes an upstream portion extending from the inlet and a downstream portion extending from the outlet. The turbine system further includes a rib extending from an outer surface of the duct passage, the rib dividing the upstream portion and the downstream portion.

  10. Divided Saphenectomy for Varicose Vein in Ambulatory Surgery

    PubMed Central

    2014-01-01

    We performed divided saphenectomy (DS) for varicose vein in ambulatory surgery with minimal incisions. Under tumescent local anesthesia, this procedure ligates all perforators in the thigh, preserving a route of venous drainage, and reduces bruising by ligating all tributaries. Also, DS does not need any special surgical instrument. Subcutaneous inguinal hemorrhage was observed in 4.9% (3/61), mild bruises were observed in 19.7% (12/61), and saphenous nerve neuralgia was 1.6% (1/61). Wound infection, deep venous thrombosis, and edema were not observed. DS is a minimally invasive, simple, and cost-effective procedure. PMID:24995071

  11. Pump tank divider plate for sump suction sodium pumps

    DOEpatents

    George, John A.; Nixon, Donald R.

    1977-01-01

    A circular plate extends across the diameter of "sump suction" pump, with a close clearance between the edge of the plate and the wall of the pump tank. The plate is located above the pump impeller, inlet and outlet flow nozzles but below the sodium free surface and effectively divides the pump tank into two separate chambers. On change of pump speed, the close fitting flow restriction plate limits the rate of flow into or out of the upper chamber, thereby minimizing the rate of level change in the tank and permitting time for the pump cover gas pressure to be varied to maintain an essentially constant level.

  12. Cellular Contraction and Polarization Drive Collective Cellular Motion.

    PubMed

    Notbohm, Jacob; Banerjee, Shiladitya; Utuje, Kazage J C; Gweon, Bomi; Jang, Hwanseok; Park, Yongdoo; Shin, Jennifer; Butler, James P; Fredberg, Jeffrey J; Marchetti, M Cristina

    2016-06-21

    Coordinated motions of close-packed multicellular systems typically generate cooperative packs, swirls, and clusters. These cooperative motions are driven by active cellular forces, but the physical nature of these forces and how they generate collective cellular motion remain poorly understood. Here, we study forces and motions in a confined epithelial monolayer and make two experimental observations: 1) the direction of local cellular motion deviates systematically from the direction of the local traction exerted by each cell upon its substrate; and 2) oscillating waves of cellular motion arise spontaneously. Based on these observations, we propose a theory that connects forces and motions using two internal state variables, one of which generates an effective cellular polarization, and the other, through contractile forces, an effective cellular inertia. In agreement with theoretical predictions, drugs that inhibit contractility reduce both the cellular effective elastic modulus and the frequency of oscillations. Together, theory and experiment provide evidence suggesting that collective cellular motion is driven by at least two internal variables that serve to sustain waves and to polarize local cellular traction in a direction that deviates systematically from local cellular velocity. PMID:27332131

  13. Integrated cellular systems

    NASA Astrophysics Data System (ADS)

    Harper, Jason C.

    The generation of new three-dimensional (3D) matrices that enable integration of biomolecular components and whole cells into device architectures, without adversely altering their morphology or activity, continues to be an expanding and challenging field of research. This research is driven by the promise that encapsulated biomolecules and cells can significantly impact areas as diverse as biocatalysis, controlled delivery of therapeutics, environmental and industrial process monitoring, early warning of warfare agents, bioelectronics, photonics, smart prosthetics, advanced physiological sensors, portable medical diagnostic devices, and tissue/organ replacement. This work focuses on the development of a fundamental understanding of the biochemical and nanomaterial mechanisms that govern the cell directed assembly and integration process. It was shown that this integration process relies on the ability of cells to actively develop a pH gradient in response to evaporation induced osmotic stress, which catalyzes silica condensation within a thin 3D volume surrounding the cells, creating a functional bio/nano interface. The mechanism responsible for introducing functional foreign membrane-bound proteins via proteoliposome addition to the silica-lipid-cell matrix was also determined. Utilizing this new understanding, 3D cellular immobilization capabilities were extended using sol-gel matrices endowed with glycerol, trehalose, and media components. The effects of these additives, and the metabolic phase of encapsulated S. cerivisiase cells, on long-term viability and the rate of inducible gene expression was studied. This enabled the entrapment of cells within a novel microfluidic platform capable of simultaneous colorimetric, fluorescent, and electrochemical detection of a single analyte, significantly improving confidence in the biosensor output. As a complementary approach, multiphoton protein lithography was utilized to engineer 3D protein matrices in which to

  14. Energetics and genetics across the prokaryote-eukaryote divide

    PubMed Central

    2011-01-01

    Background All complex life on Earth is eukaryotic. All eukaryotic cells share a common ancestor that arose just once in four billion years of evolution. Prokaryotes show no tendency to evolve greater morphological complexity, despite their metabolic virtuosity. Here I argue that the eukaryotic cell originated in a unique prokaryotic endosymbiosis, a singular event that transformed the selection pressures acting on both host and endosymbiont. Results The reductive evolution and specialisation of endosymbionts to mitochondria resulted in an extreme genomic asymmetry, in which the residual mitochondrial genomes enabled the expansion of bioenergetic membranes over several orders of magnitude, overcoming the energetic constraints on prokaryotic genome size, and permitting the host cell genome to expand (in principle) over 200,000-fold. This energetic transformation was permissive, not prescriptive; I suggest that the actual increase in early eukaryotic genome size was driven by a heavy early bombardment of genes and introns from the endosymbiont to the host cell, producing a high mutation rate. Unlike prokaryotes, with lower mutation rates and heavy selection pressure to lose genes, early eukaryotes without genome-size limitations could mask mutations by cell fusion and genome duplication, as in allopolyploidy, giving rise to a proto-sexual cell cycle. The side effect was that a large number of shared eukaryotic basal traits accumulated in the same population, a sexual eukaryotic common ancestor, radically different to any known prokaryote. Conclusions The combination of massive bioenergetic expansion, release from genome-size constraints, and high mutation rate favoured a protosexual cell cycle and the accumulation of eukaryotic traits. These factors explain the unique origin of eukaryotes, the absence of true evolutionary intermediates, and the evolution of sex in eukaryotes but not prokaryotes. Reviewers This article was reviewed by: Eugene Koonin, William Martin

  15. Stratified Flow Past a Hill: Dividing Streamline Concept Revisited

    NASA Astrophysics Data System (ADS)

    Leo, Laura S.; Thompson, Michael Y.; Di Sabatino, Silvana; Fernando, Harindra J. S.

    2016-06-01

    The Sheppard formula (Q J R Meteorol Soc 82:528-529, 1956) for the dividing streamline height H_s assumes a uniform velocity U_∞ and a constant buoyancy frequency N for the approach flow towards a mountain of height h, and takes the form H_s/h=( {1-F} ) , where F=U_{∞}/Nh. We extend this solution to a logarithmic approach-velocity profile with constant N. An analytical solution is obtained for H_s/h in terms of Lambert-W functions, which also suggests alternative scaling for H_s/h. A `modified' logarithmic velocity profile is proposed for stably stratified atmospheric boundary-layer flows. A field experiment designed to observe H_s is described, which utilized instrumentation from the spring field campaign of the Mountain Terrain Atmospheric Modeling and Observations (MATERHORN) Program. Multiple releases of smoke at F≈ 0.3-0.4 support the new formulation, notwithstanding the limited success of experiments due to logistical constraints. No dividing streamline is discerned for F≈ 10, since, if present, it is too close to the foothill. Flow separation and vortex shedding is observed in this case. The proposed modified logarithmic profile is in reasonable agreement with experimental observations.

  16. Engineering Cellular Metabolism.

    PubMed

    Nielsen, Jens; Keasling, Jay D

    2016-03-10

    Metabolic engineering is the science of rewiring the metabolism of cells to enhance production of native metabolites or to endow cells with the ability to produce new products. The potential applications of such efforts are wide ranging, including the generation of fuels, chemicals, foods, feeds, and pharmaceuticals. However, making cells into efficient factories is challenging because cells have evolved robust metabolic networks with hard-wired, tightly regulated lines of communication between molecular pathways that resist efforts to divert resources. Here, we will review the current status and challenges of metabolic engineering and will discuss how new technologies can enable metabolic engineering to be scaled up to the industrial level, either by cutting off the lines of control for endogenous metabolism or by infiltrating the system with disruptive, heterologous pathways that overcome cellular regulation. PMID:26967285

  17. Cellular Morphogenesis In Silico

    PubMed Central

    Shinbrot, Troy; Chun, Young; Caicedo-Carvajal, Carlos; Foty, Ramsey

    2009-01-01

    Abstract We describe a model that simulates spherical cells of different types that can migrate and interact either attractively or repulsively. We find that both expected morphologies and previously unreported patterns spontaneously self-assemble. Among the newly discovered patterns are a segmented state of alternating discs, and a “shish-kebab” state, in which one cell type forms a ring around a second type. We show that these unique states result from cellular attraction that increases with distance (e.g., as membranes stretch viscoelastically), and would not be seen in traditional, e.g., molecular, potentials that diminish with distance. Most of the states found computationally have been observed in vitro, and it remains to be established what role these self-assembled states may play in in vivo morphogenesis. PMID:19686642

  18. Drainage divide migration induced by rainfall gradient in orogenic landscape and the split of the associated drainage networks

    NASA Astrophysics Data System (ADS)

    Bonnet, S.

    2009-12-01

    Although numerical models demonstrate that topography in orogens is asymmetric when forced by orographic precipitations, drainage divide migration (the mechanism responsible for this asymmetry) has never been documented in natural orogens, even though the latter actually exhibits an asymmetric topography in most cases (e. g., Taiwan, southern Alps). Drainage divide migration is investigated here in the laboratory modelling of erosion and landscape dynamics under spatially-constant uplift forcing but with a lateral precipitation gradient. As observed numerically, precipitation gradient induces the migration of the drainage divide toward the drier side of the landscape and the development of an asymmetric topography. The divide is simultaneously uplifted such that the mean topographic slope of the wetter side of the landscape remains constant during its elongation. On the opposite, the progressive shortening of the drier side of the landscape results in a progressive steepening of its topography. This leads to a very unstable landscape and an original mechanism that splits the drainage networks is observed there: each initial drainage network progressively splits into two individual networks that become separated by the growth of a new hillcrest. Through this mechanism, the numbers of drainage basins extending to the main divide increases during divide migration such that the universal law of drainage outlet spacing is maintained. Given the pattern of rainfall, the migration of the drainage divide induces a continuous decrease in the mean runoff within the drainage basins located on the drier side of the landscape. There, the area of the drainage basins decreases because of the combination of (i) the continuous size reduction which is the direct consequence of the divide migration, and (ii) the abrupt size reduction consecutive to the split of the drainage networks and the individuation of two drainage basins from a previous single one. By continually reducing the

  19. Shifting brain asymmetry: the link between meditation and structural lateralization.

    PubMed

    Kurth, Florian; MacKenzie-Graham, Allan; Toga, Arthur W; Luders, Eileen

    2015-01-01

    Previous studies have revealed an increased fractional anisotropy and greater thickness in the anterior parts of the corpus callosum in meditation practitioners compared with control subjects. Altered callosal features may be associated with an altered inter-hemispheric integration and the degree of brain asymmetry may also be shifted in meditation practitioners. Therefore, we investigated differences in gray matter asymmetry as well as correlations between gray matter asymmetry and years of meditation practice in 50 long-term meditators and 50 controls. We detected a decreased rightward asymmetry in the precuneus in meditators compared with controls. In addition, we observed that a stronger leftward asymmetry near the posterior intraparietal sulcus was positively associated with the number of meditation practice years. In a further exploratory analysis, we observed that a stronger rightward asymmetry in the pregenual cingulate cortex was negatively associated with the number of practice years. The group difference within the precuneus, as well as the positive correlations with meditation years in the pregenual cingulate cortex, suggests an adaptation of the default mode network in meditators. The positive correlation between meditation practice years and asymmetry near the posterior intraparietal sulcus may suggest that meditation is accompanied by changes in attention processing. PMID:24643652

  20. Evaluation of Limb Load Asymmetry Using Two New Mathematical Models

    PubMed Central

    Kumar, Senthil NS; Omar, Baharudin; Joseph, Leonard H.; Htwe, Ohnmar; Jagannathan, K.; Hamdan, Nor M Y; Rajalakshmi, D.

    2015-01-01

    Quantitative measurement of limb loading is important in orthopedic and neurological rehabilitation. In current practice, mathematical models such as Symmetry index (SI), Symmetry ratio (SR), and Symmetry angle (SA) are used to quantify limb loading asymmetry. Literatures have identified certain limitations with the above mathematical models. Hence this study presents two new mathematical models Modified symmetry index (MSI) and Limb loading error (LLE) that would address these limitations. Furthermore, the current mathematical models were compared against the new model with the goal of achieving a better model. This study uses hypothetical data to simulate an algorithmic preliminary computational measure to perform with all numerical possibilities of even and uneven limb loading that can occur in human legs. Descriptive statistics are used to interpret the limb loading patterns: symmetry, asymmetry and maximum asymmetry. The five mathematical models were similar in analyzing symmetry between limbs. However, for asymmetry and maximum asymmetry data, the SA and SR values do not give any meaningful interpretation, and SI gives an inflated value. The MSI and LLE are direct, easy to interpret and identify the loading patterns with the side of asymmetry. The new models are notable as they quantify the amount and side of asymmetry under different loading patterns. PMID:25716372

  1. Shifting brain asymmetry: the link between meditation and structural lateralization

    PubMed Central

    Kurth, Florian; MacKenzie-Graham, Allan; Toga, Arthur W.

    2015-01-01

    Previous studies have revealed an increased fractional anisotropy and greater thickness in the anterior parts of the corpus callosum in meditation practitioners compared with control subjects. Altered callosal features may be associated with an altered inter-hemispheric integration and the degree of brain asymmetry may also be shifted in meditation practitioners. Therefore, we investigated differences in gray matter asymmetry as well as correlations between gray matter asymmetry and years of meditation practice in 50 long-term meditators and 50 controls. We detected a decreased rightward asymmetry in the precuneus in meditators compared with controls. In addition, we observed that a stronger leftward asymmetry near the posterior intraparietal sulcus was positively associated with the number of meditation practice years. In a further exploratory analysis, we observed that a stronger rightward asymmetry in the pregenual cingulate cortex was negatively associated with the number of practice years. The group difference within the precuneus, as well as the positive correlations with meditation years in the pregenual cingulate cortex, suggests an adaptation of the default mode network in meditators. The positive correlation between meditation practice years and asymmetry near the posterior intraparietal sulcus may suggest that meditation is accompanied by changes in attention processing. PMID:24643652

  2. NODAL PATHWAY GENES ARE DOWNREGULATED IN FACIAL ASYMMETRY

    PubMed Central

    Nicot, Romain; Hottenstein, Molly; Raoul, Gwenael; Ferri, Joel; Horton, Michael; Tobias, John W.; Barton, Elisabeth; Gelé, Patrick; Sciote, James J.

    2014-01-01

    Purpose Facial asymmetry is a common comorbid condition in patients with jaw deformation malocclusion. Heritability of malocclusion is advancing rapidly, but very little is known regarding genetic contributions to asymmetry. This study identifies differences in expression of key asymmetry-producing genes which are down regulated in facial asymmetry patients. Material and Methods Masseter muscle samples were collected during BSSO orthognathic surgery to correct skeletal-based malocclusion. Patients were classified as Class II or III and open or deep bite malocclusion with or without facial asymmetry. Muscle samples were analyzed for gene expression differences on Affymetrix HT2.0 microarray global expression chips. Results Overall gene expression was different for asymmetric patients compared to other malocclusion classifications by principal component analysis (P<0.05). We identified differences in the nodal signaling pathway (NSP) which promotes development of mesoderm and endoderm and left-right patterning during embryogenesis. Nodal and Lefty expression was 1.39–1.84 fold greater (P<3.41×10−5) whereas integral membrane Nodal-modulators Nomo1,2,3 were −5.63 to −5.81 (P<3.05×10−4) less in asymmetry subjects. Fold differences among intracellular pathway members were negative in the range of −7.02 to −2.47 (P<0.003). Finally Pitx2, a upstream effector of Nodal known to influence the size of type II skeletal muscle fibers was also significantly decreased in facial asymmetry (P<0.05). Conclusions When facial asymmetry is part of skeletal malocclusion there are decreases of NSP genes in masseter muscle. This data suggests that the NSP is down regulated to help promote development of asymmetry. Pitx2 expression differences also contributed to both skeletal and muscle development in this condition. PMID:25364968

  3. Generic Divide and Conquer Internet-Based Computing

    NASA Technical Reports Server (NTRS)

    Follen, Gregory J. (Technical Monitor); Radenski, Atanas

    2003-01-01

    The growth of Internet-based applications and the proliferation of networking technologies have been transforming traditional commercial application areas as well as computer and computational sciences and engineering. This growth stimulates the exploration of Peer to Peer (P2P) software technologies that can open new research and application opportunities not only for the commercial world, but also for the scientific and high-performance computing applications community. The general goal of this project is to achieve better understanding of the transition to Internet-based high-performance computing and to develop solutions for some of the technical challenges of this transition. In particular, we are interested in creating long-term motivation for end users to provide their idle processor time to support computationally intensive tasks. We believe that a practical P2P architecture should provide useful service to both clients with high-performance computing needs and contributors of lower-end computing resources. To achieve this, we are designing dual -service architecture for P2P high-performance divide-and conquer computing; we are also experimenting with a prototype implementation. Our proposed architecture incorporates a master server, utilizes dual satellite servers, and operates on the Internet in a dynamically changing large configuration of lower-end nodes provided by volunteer contributors. A dual satellite server comprises a high-performance computing engine and a lower-end contributor service engine. The computing engine provides generic support for divide and conquer computations. The service engine is intended to provide free useful HTTP-based services to contributors of lower-end computing resources. Our proposed architecture is complementary to and accessible from computational grids, such as Globus, Legion, and Condor. Grids provide remote access to existing higher-end computing resources; in contrast, our goal is to utilize idle processor time of

  4. Lepton asymmetry in the primordial gravitational wave spectrum

    SciTech Connect

    Ichiki, Kiyotomo; Yamaguchi, Masahide; Yokoyama, Jun'Ichi

    2007-04-15

    Effects of neutrino free streaming are evaluated on the primordial spectrum of gravitational radiation taking both neutrino chemical potential and masses into account. The former or the lepton asymmetry induces two competitive effects, namely, to increase anisotropic stress, which damps the gravitational wave more, and to delay the matter-radiation equality time, which reduces the damping. The latter effect is more prominent and a large lepton asymmetry would reduce the damping. We may thereby be able to measure the magnitude of lepton asymmetry from the primordial gravitational wave spectrum.

  5. Inert scalar doublet asymmetry as origin of dark matter

    NASA Astrophysics Data System (ADS)

    Dhen, Mikaël; Hambye, Thomas

    2015-10-01

    In the inert scalar doublet framework, we analyze what would be the effect of a B -L asymmetry that could have been produced at high temperature in the thermal bath of the Universe. We show that unless the "λ5" scalar interaction is tiny, this asymmetry is automatically reprocessed in part into an inert scalar asymmetry that could be at the origin of dark matter today. Along this scenario, the inert mass scale lies in the few-TeV range, and direct detection constraints require that the inert scalar particles decay into a lighter dark matter particle which, as the inert doublet, is odd under a Z2 symmetry.

  6. Measurement of Transverse Asymmetries from Interference Fragmentation at HERMES

    SciTech Connect

    Marco, Contalbrigo

    2007-06-13

    The HERMES experiment has measured for the first time single target-spin asymmetries in semi-inclusive two-pion production using a transversely polarized hydrogen target. These asymmetries are related to the product of two unknowns: the transversity distribution function and the interference fragmentation function. The measured asymmetries are found to be non-zero in the invariant mass range 0.51 GeV < M{pi}{pi} < 0.97 GeV, indicating that two-pion semi-inclusive deep-inelastic scattering can be used to probe transversity.

  7. Baryogenesis and dark matter through a Higgs asymmetry.

    PubMed

    Servant, Géraldine; Tulin, Sean

    2013-10-11

    In addition to explaining the masses of elementary particles, the Higgs boson may have far-reaching implications for the generation of the matter content in the Universe. For instance, the Higgs boson plays a key role in two main theories of baryogenesis, namely, electroweak baryogenesis and leptogenesis. In this Letter, we propose a new cosmological scenario where the Higgs chemical potential mediates asymmetries between visible and dark matter sectors, either generating a baryon asymmetry from a dark matter asymmetry or vice versa. We illustrate this mechanism with a simple model with two new fermions coupled to the Higgs boson and discuss the associated signatures. PMID:24160589

  8. Functional asymmetry of posture and body system regulation

    NASA Technical Reports Server (NTRS)

    Boloban, V. N.; Otsupok, A. P.

    1980-01-01

    The manifestation of functional asymmetry during the regulation of an athlete's posture and a system of bodies and its effect on the execution of individual and group acrobatic exercises were studied. Functional asymmetry of posture regulation was recorded in acrobats during the execution of individual and group exercises. It was shown that stability is maintained at the expense of bending and twisting motions. It is important to consider whether the functional asymmetry of posture regulation is left or right sided in making up pairs and groups of acrobats.

  9. CMB hemispherical asymmetry: long mode modulation and non-Gaussianity

    SciTech Connect

    Namjoo, Mohammad Hossein; Baghram, Shant; Firouzjahi, Hassan; Abolhasani, Ali Akbar E-mail: abolhasani@ipm.ir E-mail: firouz@ipm.ir

    2014-08-01

    The observed hemispherical asymmetry in CMB map can be explained by modulation from a long wavelength super horizon mode which non-linearly couples to the CMB modes. We address the criticism in [1] about the role of non-Gaussianities in squeezed and equilateral configurations in generating hemispherical asymmetry from the long mode modulation. We stress that the modulation is sensitive to the non-Gaussianity in the squeezed limit. In addition, we demonstrate the validity of our approach in providing a consistency condition relating the amplitude of dipole asymmetry to f{sub NL} in the squeezed limit.

  10. Flagellation of Pseudomonas aeruginosa in newly divided cells

    NASA Astrophysics Data System (ADS)

    Zhao, Kun; Lee, Calvin; Anda, Jaime; Wong, Gerard

    2015-03-01

    For monotrichous bacteria, Pseudomonas aeruginosa, after cell division, one daughter cell inherits the old flagellum from its mother cell, and the other grows a new flagellum during or after cell division. It had been shown that the new flagellum grows at the distal pole of the dividing cell when the two daughter cells haven't completely separated. However, for those daughter cells who grow new flagella after division, it still remains unknown at which pole the new flagellum will grow. Here, by combining our newly developed bacteria family tree tracking techniques with genetic manipulation method, we showed that for the daughter cell who did not inherit the old flagellum, a new flagellum has about 90% chances to grow at the newly formed pole. We proposed a model for flagellation of P. aeruginosa.

  11. Envy Up, Scorn Down: How Comparison Divides Us

    PubMed Central

    Fiske, Susan T.

    2013-01-01

    Comparison compels people, even as it stresses, depresses, and divides us. Comparison is only natural, but the collateral damage reveals envy upward and scorn downward, and these emotions, arguably, poison people and their relationships. Summaries of several experiments—using questionnaire, psychometric, response-time, electromyographic, and neuroimaging data—illustrate the dynamics of envy up and scorn down, as well as proposing how to mitigate their effects. Initial studies suggest the importance of status. Other data show how scorn down minimizes thought about another’s mind; power deactivates mental concepts. Regarding envy up, other studies demonstrate that Schadenfreude (malicious joy) targets envied outgroups. However, counterstereotypic information, empathy, and outcome dependency can mitigate both scorn and envy. PMID:21058760

  12. Amniotic membrane graft to reconstruct divided nevi of eyelids.

    PubMed

    Bhattacharjee, Kasturi; Singh, Manpreet; Bhattacharjee, Harsha

    2015-01-01

    Two patients with congenital divided nevi of the eyelids presented with chief symptoms of cosmetic blemish (n=2) and epiphora (n=1). All the lesions were surgically excised with histological free margins and amniotic membrane graft (AMG) was used to cover the mucosal and eyelid marginal defects. Caruncular and punctal involvement was managed with complete excision and monocanalicular stent insertion to prevent punctal stenosis. AMG provided an adequate scaffold for conjunctival regenesis and anatomic continuity was found within 6 weeks in both patients. None of them had any residual pigmentation or disease recurrence after a follow-up of more than 2.5 years. Local absence of eyelashes was the only drawback which patients masked with modern artificial eyelashes or make-up. This novel utility of AMG illustrates effective conjunctival regenesis and maintenance of mucocutaneous junction functionality. PMID:26009598

  13. The cultural divide: exploring communication barriers between scientists and clinicians

    PubMed Central

    Restifo, Linda L.; Phelan, Gerald R.

    2011-01-01

    Summary Despite remarkable advances in basic biomedical science that have led to improved patient care, there is a wide and persistent gap in the abilities of researchers and clinicians to understand and appreciate each other. In this Editorial, the authors, a scientist and a clinician, discuss the rift between practitioners of laboratory research and clinical medicine. Using their first-hand experience and numerous interviews throughout the United States, they explore the causes of this ‘cultural divide’. Members of both professions use advanced problem-solving skills and typically embark on their career paths with a deeply felt sense of purpose. Nonetheless, differences in classroom education, professional training environments, reward mechanisms and sources of drive contribute to obstacles that inhibit communication, mutual respect and productive collaboration. More than a sociological curiosity, the cultural divide is a significant barrier to the bench-to-bedside goals of translational medicine. Understanding its roots is the first step towards bridging the gap. PMID:21708897

  14. A house divided? The psychology of red and blue America.

    PubMed

    Seyle, D Conor; Newman, Matthew L

    2006-09-01

    Recently it has become commonplace in America for commentators and the public to use the terms "red" and "blue" to refer to perceived cultural differences in America and American politics. Although a political divide may exist in America today, these particular terms are inaccurate and reductive. This article presents research from social psychology demonstrating that the increased use of these terms is likely to increase the conflict between political groups in America by making political conflict salient in nonpolitical contexts, reducing the ability of Americans to form multifaceted complex identities, pushing Americans to misperceive political in-groups and out-groups, and contributing to a "spiral of silence." An alternative model for discussing cultural differences is proposed. PMID:16953745

  15. Divided Saddle Theory: A New Idea for Rate Constant Calculation.

    PubMed

    Daru, János; Stirling, András

    2014-03-11

    We present a theory of rare events and derive an algorithm to obtain rates from postprocessing the numerical data of a free energy calculation and the corresponding committor analysis. The formalism is based on the division of the saddle region of the free energy profile of the rare event into two adjacent segments called saddle domains. The method is built on sampling the dynamics within these regions: auxiliary rate constants are defined for the saddle domains and the absolute forward and backward rates are obtained by proper reweighting. We call our approach divided saddle theory (DST). An important advantage of our approach is that it requires only standard computational techniques which are available in most molecular dynamics codes. We demonstrate the potential of DST numerically on two examples: rearrangement of alanine-dipeptide (CH3CO-Ala-NHCH3) conformers and the intramolecular Cope reaction of the fluxional barbaralane molecule. PMID:26580187

  16. Segmenting and Tracking Multiple Dividing Targets Using ilastik.

    PubMed

    Haubold, Carsten; Schiegg, Martin; Kreshuk, Anna; Berg, Stuart; Koethe, Ullrich; Hamprecht, Fred A

    2016-01-01

    Tracking crowded cells or other targets in biology is often a challenging task due to poor signal-to-noise ratio, mutual occlusion, large displacements, little discernibility, and the ability of cells to divide. We here present an open source implementation of conservation tracking (Schiegg et al., IEEE international conference on computer vision (ICCV). IEEE, New York, pp 2928-2935, 2013) in the ilastik software framework. This robust tracking-by-assignment algorithm explicitly makes allowance for false positive detections, undersegmentation, and cell division. We give an overview over the underlying algorithm and parameters, and explain the use for a light sheet microscopy sequence of a Drosophila embryo. Equipped with this knowledge, users will be able to track targets of interest in their own data. PMID:27207368

  17. Four Sided Domains in Hierarchical Space Dividing Patterns

    NASA Astrophysics Data System (ADS)

    Bohn, S.; Douady, S.; Couder, Y.

    2005-02-01

    The cracks observed in the glaze of ceramics form networks, which divide the 2D plane into domains. It is shown that, on the average, the number of sides of these domains is four. This contrasts with the usual 2D space divisions observed in Voronoi tessellation or 2D soap froths. In the latter networks, the number of sides of a domain coincides with the number of its neighbors, which, according to Euler’s theorem, has to be six on average. The four sided property observed in cracks is the result of a formation process which can be understood as the successive divisions of domains with no later reorganization. It is generic for all networks having such hierarchical construction rules. We introduce a “geometrical charge,” analogous to Euler’s topological charge, as the difference from four of the number of sides of a domain. It is preserved during the pattern formation of the crack pattern.

  18. Dividing the Janus vasculitis? Pathophysiology of eosinophilic granulomatosis with polyangitis.

    PubMed

    Chaigne, Benjamin; Terrier, Benjamin; Thieblemont, Nathalie; Witko-Sarsat, Véronique; Mouthon, Luc

    2016-02-01

    Eosinophilic granulomatosis with polyangitis (EGPA) is a rare small- and medium-sized vessel vasculitis belonging to the group of anti-neutrophil cytoplasm antibody (ANCA)-associated vasculitides (AAV). It is commonly divided into two phenotypes depending on the presence of ANCAs targeting myeloperoxidase (MPO). MPO-ANCAs are present in 31% to 38% of patients and are associated with a vasculitis phenotype of the disease, whereas patients without MPO-ANCA are at risk of cardiac involvement. Despite significant advances in understanding the overall pathogenesis of the disease, the explanation for this dichotomy is still unclear. In this review, we synthesize our knowledge of the pathogenesis of EGPA and attempt to i) distinguish EGPA from other diseases including other AAVs, asthma, allergy and hypereosinophilic-associated conditions and ii) speculate about the preponderant mechanisms, which could explain the two disease phenotypes. PMID:26506114

  19. Size and emotion averaging: costs of dividing attention after all.

    PubMed

    Brand, John; Oriet, Chris; Tottenham, Laurie Sykes

    2012-03-01

    Perceptual averaging is a process by which sets of similar items are represented by summary statistics such as their average size, luminance, or orientation. Researchers have argued that this process is automatic, able to be carried out without interference from concurrent processing. Here, we challenge this conclusion and demonstrate a reliable cost of computing the mean size of circles distinguished by colour (Experiments 1 and 2) and the mean emotionality of faces distinguished by sex (Experiment 3). We also test the viability of two strategies that could have allowed observers to guess the correct response without computing the average size or emotionality of both sets concurrently. We conclude that although two means can be computed concurrently, doing so incurs a cost of dividing attention. PMID:22390476

  20. Divided-pulse nonlinear amplification and simultaneous compression

    SciTech Connect

    Hao, Qiang; Zhang, Qingshan; Sun, Tingting; Chen, Jie; Wang, Yuqing; Guo, Zhengru; Yang, Kangwen; Guo, Zhanhua; Zeng, Heping

    2015-03-09

    We report on a fiber laser system delivering 122 fs pulse duration and 600 mW average power at 1560 nm by the interplay between divided pulse amplification and nonlinear pulse compression. A small-core double-clad erbium-doped fiber with anomalous dispersion carries out the pulse amplification and simultaneously compresses the laser pulses such that a separate compressor is no longer necessary. A numeric simulation reveals the existence of an optimum fiber length for producing transform-limited pulses. Furthermore, frequency doubling to 780 nm with 240 mW average power and 98 fs pulse duration is achieved by using a periodically poled lithium niobate crystal at room temperature.

  1. Microfluidic Electroporation for Cellular Analysis and Delivery

    PubMed Central

    Geng, Tao

    2013-01-01

    Electroporation is a simple yet powerful technique for breaching cell membrane barrier. The applications of electroporation can be generally divided into two categories: the release of intracellular proteins, nucleic acids and other metabolites for analysis and the delivery of exogenous reagents such as genes, drugs and nanoparticles with therapeutic purposes or for cellular manipulation. In this review, we go over the basic physics associated with cell electroporation and highlight recent technological advances on microfluidic platforms for conducting electroporation. Within the context of its working mechanism, we summarize the accumulated knowledge on how the parameters of electroporation affect its performance for various tasks. We discuss various strategies and designs for conducting electroporation at microscale and then focus on analysis of intracellular contents and delivery of exogenous agents as two major applications of the technique. Finally, an outlook for future applications of microfluidic electroporation in increasingly diverse utilities is presented. PMID:23917998

  2. Cellular proliferation after experimental glaucoma filtration surgery

    SciTech Connect

    Jampel, H.D.; McGuigan, L.J.; Dunkelberger, G.R.; L'Hernault, N.L.; Quigley, H.A.

    1988-01-01

    We used light microscopic autoradiography to determine the time course of cellular incorporation of tritiated thymidine (a correlate of cell division) following glaucoma filtration surgery in seven eyes of four cynomolgus monkeys with experimental glaucoma. Incorporation of tritiated thymidine was detected as early as 24 hours postoperatively. Peak incorporation occurred five days postoperatively and had returned to baseline levels by day 11. Cells incorporating tritiated thymidine included keratocytes, episcleral cells, corneal and capillary endothelial cells, and conjunctival and corneal epithelial cells. Transmission electron microscopy was correlated with the autoradiographic results to demonstrate that fibroblasts were dividing on the corneoscleral margin. These findings have potential clinical implications for the use of antiproliferative agents after filtration surgery.

  3. Divided Attention and Processes Underlying Sense of Agency

    PubMed Central

    Wen, Wen; Yamashita, Atsushi; Asama, Hajime

    2016-01-01

    Sense of agency refers to the subjective feeling of controlling events through one’s behavior or will. Sense of agency results from matching predictions of one’s own actions with actual feedback regarding the action. Furthermore, when an action involves a cued goal, performance-based inference contributes to sense of agency. That is, if people achieve their goal, they would believe themselves to be in control. Previous studies have shown that both action-effect comparison and performance-based inference contribute to sense of agency; however, the dominance of one process over the other may shift based on task conditions such as the presence or absence of specific goals. In this study, we examined the influence of divided attention on these two processes underlying sense of agency in two conditions. In the experimental task, participants continuously controlled a moving dot for 10 s while maintaining a string of three or seven digits in working memory. We found that when there was no cued goal (no-cued-goal condition), sense of agency was impaired by high cognitive load. Contrastingly, when participants controlled the dot based on a cued goal (cued-goal-directed condition), their sense of agency was lower than in the no-cued-goal condition and was not affected by cognitive load. The results suggest that the action-effect comparison process underlying sense of agency requires attention. On the other hand, the weaker influence of divided attention in the cued-goal-directed condition could be attributed to the dominance of performance-based inference, which is probably automatic. PMID:26858680

  4. Further reflections on the humanistic psychology-positive psychology divide.

    PubMed

    Waterman, Alan S

    2014-01-01

    Replies to comments by Morley (see record 2014-01475-010), Serlin (see record 2014-01475-011), Friedman (see record 2014-01475-012), Churchill and Mruk (see record 2014-01475-013), and Schneider (see record 2014-01475-014) on the current author's original article "The humanistic psychology-positive psychology divide: Contrasts in philosophical foundations" (see record 2013-12501-001). The article contrasting humanistic psychology and positive psychology with respect to their ontological, epistemological, and practical philosophical foundations has generated commentaries from leading proponents of varying perspectives within humanistic psychology. There is a great deal of material within those commentaries with which the current author is in full accord. It is worth noting at the outset that no one appears to be challenging the observations (a) that published exchanges between proponents of humanistic and positive psychology have been marked by tension and ambivalence, albeit with occasional efforts at reconciliation and rapprochement; (b) that proponents of the two perspectives differ with respect to the philosophers they most frequently cite in their writings; or (c) that such citations reflect the philosophical assumptions serving as foundations for the theoretical, research, and counseling/therapeutic endeavors of psychologists in both groups. The principal points of concurrence in the critiques published here are that the current underestimates the extent to which mutually supportive, collaborative work can be accomplished across the philosophical divide and that the recommendations the current author has made has advanced serious potential negative consequences for the field. The current author will address these points here in the reply, although space does not permit him to address other substantive points raised by individual commentators. PMID:24446855

  5. Older people and digital disengagement: a fourth digital divide?

    PubMed

    Olphert, Wendy; Damodaran, Leela

    2013-01-01

    Digital technologies are becoming more pervasive in all areas of society. Enabling everyone to have access and capability to use the Internet and associated digital technologies, summed up in the term 'digital inclusion', is seen to have wide-ranging benefits to the individual, to the economy and to society. For older people, being digitally included can help them to maintain their independence, social connectedness and sense of worth in the face of declining health or limited capabilities, as well as also offering new opportunities to improve their quality of life. At present however, access to the technology and to the benefits is not equally distributed either between or within nations, and older people tend to be on the 'wrong' side of what is termed the 'digital divide'. Governments globally are developing strategies to promote digital inclusion and indeed Internet uptake is increasing steadily, including amongst older people. However, such strategies have focussed on getting people online, and there appears to be an assumption that once someone is online they will remain 'digitally engaged'. In fact statistics show that some users give up using the Internet, and there is emerging evidence that older people are more vulnerable to the factors which can lead to this outcome. The authors see this phenomenon as a potential but largely unrecognised 'fourth digital divide' which has serious implications for social inclusion. The objectives of this article are (a) to raise awareness of the phenomenon of digital disengagement by considering some of the emerging evidence, (b) to explore some of the potential implications of not recognising and therefore not addressing the needs of the digitally disengaged older population, and (c) to reveal the prevailing gap in knowledge which future research should address. PMID:23969758

  6. Spike sorting for polytrodes: a divide and conquer approach

    PubMed Central

    Swindale, Nicholas V.; Spacek, Martin A.

    2014-01-01

    In order to determine patterns of neural activity, spike signals recorded by extracellular electrodes have to be clustered (sorted) with the aim of ensuring that each cluster represents all the spikes generated by an individual neuron. Many methods for spike sorting have been proposed but few are easily applicable to recordings from polytrodes which may have 16 or more recording sites. As with tetrodes, these are spaced sufficiently closely that signals from single neurons will usually be recorded on several adjacent sites. Although this offers a better chance of distinguishing neurons with similarly shaped spikes, sorting is difficult in such cases because of the high dimensionality of the space in which the signals must be classified. This report details a method for spike sorting based on a divide and conquer approach. Clusters are initially formed by assigning each event to the channel on which it is largest. Each channel-based cluster is then sub-divided into as many distinct clusters as possible. These are then recombined on the basis of pairwise tests into a final set of clusters. Pairwise tests are also performed to establish how distinct each cluster is from the others. A modified gradient ascent clustering (GAC) algorithm is used to do the clustering. The method can sort spikes with minimal user input in times comparable to real time for recordings lasting up to 45 min. Our results illustrate some of the difficulties inherent in spike sorting, including changes in spike shape over time. We show that some physiologically distinct units may have very similar spike shapes. We show that RMS measures of spike shape similarity are not sensitive enough to discriminate clusters that can otherwise be separated by principal components analysis (PCA). Hence spike sorting based on least-squares matching to templates may be unreliable. Our methods should be applicable to tetrodes and scalable to larger multi-electrode arrays (MEAs). PMID:24574979

  7. Measuring mandibular asymmetry in Class I normal subjects using 3D novel coordinate system

    PubMed Central

    Kheir, Nadia Abou; Kau, Chung How

    2014-01-01

    Introduction: Orthodontic treatment plays a major role in cosmetic dentistry. A harmonious facial balance is normally the end point in comprehensive orthodontic outcomes. In order to achieve this goal, correct diagnosis of asymmetry should be done starting from the outer facial morphology forms and progressively moving to the dental occlusion. The prime importance of measuring mandibular asymmetry is its tremendous effect on the occlusion. Objective: The aim of this study was to measure mandibular asymmetry in a cohort Class I molar relationship comparing right and left sides using new three-dimensions (3D) imaging technique with the aid of 3D software (in vivo 5.2.3 [San Jose, CA]). Materials and Methods: 35 DICOM files were initially collected retrospectively and seven were excluded due to (1) condylar resorption, (2) history of trauma and (3) unclear DICOM file. A new coordinate system was set for the mid-sagittal plane (MSP), Frankfort horizontal plane and frontal plane (FP). Each cone beam computed tomography (CBCT) was appraised using 16 evaluation criteria bilaterally. Five mandibular landmarks were selected: Condylion_R, Gonion_R, Menton, Gonion_L and Condylion_L. Using these points, the mandible was further divided into four parts: (1) Ramus length right side, body of the mandible right side, body of the Ramus left side and Ramus length left side. The angles between each line and the three different planes were acquired in order to compare each line from a 3D aspect. Mean and standard deviation were calculated for the 28 CBCTs. Results: Significant bilateral differences were reported in the angle between the ramus length and MSP and the ramus length and the FP (P < 0.05). Significant lateroanterior shift of the mandibular ramus on the left side in comparison with the right side. Conclusion: Viewing an object using three different angles between the four parts of the mandible and each plane is a valid method to replicate the actual object. PMID:24987596

  8. Shrinking and splitting of drainage basins along the Aconquija Range (Argentina) from the migration of its main drainage divide

    NASA Astrophysics Data System (ADS)

    Grimaud, J.; Bonnet, S.; Moyano, S.

    2010-12-01

    Although numerical models demonstrate that topography in orogens is asymmetric when forced by orographic precipitations, drainage divide migration (the mechanism responsible for this asymmetry) has never been documented in natural orogens, even though the latter actually exhibits an asymmetric topography in most cases (e. g., Taiwan, southern Alps). Investigation of drainage divide migration in the laboratory modelling of erosion and landscape dynamics under spatially-constant uplift forcing but with a lateral precipitation gradient shows that as observed numerically, precipitation gradient induces the migration of the drainage divide toward the drier side of the landscape and the development of an asymmetric topography (Bonnet, 2009). The progressive shortening of the drier side of the landscape results in a progressive steepening of its topography. This leads to a very unstable landscape and an original mechanism that splits the drainage networks is observed there: each initial drainage network progressively splits into two individual networks that become separated by the growth of a new hillcrest (Bonnet, 2009). Through this mechanism, the numbers of drainage basins extending to the main divide increases during divide migration such that the universal law of drainage outlet spacing is maintained. The mechanism of network splitting proposed on the basis of experiments leads to transient dynamics that are exemplified by the Sierra Aconquija range in the Sierras Pampeanas province of NW Argentina. The Aconquija is an uplifted basement range, bounded by active high-angle reverse faults on one or both sides. It currently forms a prominent landscape above its adjacent foreland plains, reaching elevations greater than 5 km. Because of its location on the eastern front of the Andes, representing a major topographic barrier to the moisture flux coming from the Atlantic Ocean, the Sierra Aconquija is an orographic barrier: the eastern flank receives much more

  9. Cellular energy metabolism

    SciTech Connect

    Glaser, M.

    1991-06-01

    Studies have been carried out on adenylate kinase which is an important enzyme in determining the concentrations of the adenine nucleotides. An efficient method has been developed to clone mutant adenylate kinase genes in E. coli. Site-specific mutagenesis of the wild type gene also has been used to obtain forms of adenylate kinase with altered amino acids. The wild type and mutant forms of adenylate kinase have been overexpressed and large quantities were readily isolated. The kinetic and fluorescence properties of the different forms of adenylate kinase were characterized. This has led to a new model for the location of the AMP and ATP bindings sites on the enzyme and a proposal for the mechanism of substrate inhibition. Crystals of the wild type enzyme were obtained that diffract to at least 2.3 {angstrom} resolution. Experiments were also initiated to determine the function of adenylate kinase in vivo. In one set of experiments, E. coli strains with mutations in adenylate kinase showed large changes in cellular nucleotides after reaching the stationary phase in a low phosphate medium. This was caused by selective proteolytic degradation of the mutant adenylate kinase caused by phosphate starvation.

  10. Molecular and Cellular Biophysics

    NASA Astrophysics Data System (ADS)

    Jackson, Meyer B.

    2006-01-01

    Molecular and Cellular Biophysics provides advanced undergraduate and graduate students with a foundation in the basic concepts of biophysics. Students who have taken physical chemistry and calculus courses will find this book an accessible and valuable aid in learning how these concepts can be used in biological research. The text provides a rigorous treatment of the fundamental theories in biophysics and illustrates their application with examples. Conformational transitions of proteins are studied first using thermodynamics, and subsequently with kinetics. Allosteric theory is developed as the synthesis of conformational transitions and association reactions. Basic ideas of thermodynamics and kinetics are applied to topics such as protein folding, enzyme catalysis and ion channel permeation. These concepts are then used as the building blocks in a treatment of membrane excitability. Through these examples, students will gain an understanding of the general importance and broad applicability of biophysical principles to biological problems. Offers a unique synthesis of concepts across a wide range of biophysical topics Provides a rigorous theoretical treatment, alongside applications in biological systems Author has been teaching biophysics for nearly 25 years

  11. Electrosurgery with cellular precision.

    PubMed

    Palanker, Daniel V; Vankov, Alexander; Huie, Philip

    2008-02-01

    Electrosurgery, one of the most-often used surgical tools, is a robust but somewhat crude technology that has changed surprisingly little since its invention almost a century ago. Continuous radiofrequency is still used for tissue cutting, with thermal damage extending to hundreds of micrometers. In contrast, lasers developed 70 years later, have been constantly perfected, and the laser-tissue interactions explored in great detail, which has allowed tissue ablation with cellular precision in many laser applications. We discuss mechanisms of tissue damage by electric field, and demonstrate that electrosurgery with properly optimized waveforms and microelectrodes can rival many advanced lasers. Pulsed electric waveforms with burst durations ranging from 10 to 100 micros applied via insulated planar electrodes with 12 microm wide exposed edges produced plasma-mediated dissection of tissues with the collateral damage zone ranging from 2 to 10 microm. Length of the electrodes can vary from micrometers to centimeters and all types of soft tissues-from membranes to cartilage and skin could be dissected in liquid medium and in a dry field. This technology may allow for major improvements in outcomes of the current surgical procedures and development of much more refined surgical techniques. PMID:18270030

  12. Active Cellular Nematics

    NASA Astrophysics Data System (ADS)

    Duclos, Guillaume; Erlenkaemper, Christoph; Garcia, Simon; Yevick, Hannah; Joanny, Jean-François; Silberzan, Pascal; Biology inspired physics at mesoscales Team; Physical approach of biological problems Team

    We study the emergence of a nematic order in a two-dimensional tissue of apolar elongated fibroblast cells. Initially, these cells are very motile and the monolayer is characterized by giant density fluctuations, a signature of far-from-equilibrium systems. As the cell density increases because of proliferation, the cells align with each other forming large perfectly oriented domains while the cellular movements slow down and eventually freeze. Therefore topological defects characteristic of nematic phases remain trapped at long times, preventing the development of infinite domains. By analogy with classical non-active nematics, we have investigated the role of boundaries and we have shown that cells confined in stripes of width smaller than typically 500 µm are perfectly aligned in the stripe direction. Experiments performed in cross-shaped patterns show that both the number of cells and the degree of alignment impact the final orientation. Reference: Duclos G., Garcia S., Yevick H.G. and Silberzan P., ''Perfect nematic order in confined monolayers of spindle-shaped cells'', Soft Matter, 10, 14, 2014

  13. Nucleotide-induced asymmetry within ATPase activator ring drives σ54-RNAP interaction and ATP hydrolysis

    SciTech Connect

    Sysoeva, Tatyana A.; Chowdhury, Saikat; Guo, Liang; Nixon, B. Tracy

    2013-12-10

    It is largely unknown how the typical homomeric ring geometry of ATPases associated with various cellular activities enables them to perform mechanical work. Small-angle solution X-ray scattering, crystallography, and electron microscopy (EM) reconstructions revealed that partial ATP occupancy caused the heptameric closed ring of the bacterial enhancer-binding protein (bEBP) NtrC1 to rearrange into a hexameric split ring of striking asymmetry. The highly conserved and functionally crucial GAFTGA loops responsible for interacting with σ54–RNA polymerase formed a spiral staircase. We propose that splitting of the ensemble directs ATP hydrolysis within the oligomer, and the ring's asymmetry guides interaction between ATPase and the complex of σ54 and promoter DNA. Similarity between the structure of the transcriptional activator NtrC1 and those of distantly related helicases Rho and E1 reveals a general mechanism in homomeric ATPases whereby complex allostery within the ring geometry forms asymmetric functional states that allow these biological motors to exert directional forces on their target macromolecules.

  14. 47 CFR 22.909 - Cellular markets.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 2 2013-10-01 2013-10-01 false Cellular markets. 22.909 Section 22.909... Cellular Radiotelephone Service § 22.909 Cellular markets. Cellular markets are standard geographic areas used by the FCC for administrative convenience in the licensing of cellular systems. Cellular...

  15. 47 CFR 22.909 - Cellular markets.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 2 2014-10-01 2014-10-01 false Cellular markets. 22.909 Section 22.909... Cellular Radiotelephone Service § 22.909 Cellular markets. Cellular markets are standard geographic areas used by the FCC for administrative convenience in the licensing of cellular systems. Cellular...

  16. Asymmetries in the dust flux at Mercury

    NASA Astrophysics Data System (ADS)

    Borin, P.; Cremonese, G.; Bruno, M.; Marzari, F.

    2016-01-01

    The planet Mercury has an extended and tenuous exosphere made up of atoms that are ejected from the surface by energetic processes, including hypervelocity micrometeoritic impacts, photon-stimulated desorption by UV radiation, and ion sputtering. Meteoroid impacts of particles smaller than 1 cm, which are important for replenishing the exosphere daily, are not well-studied. We present a systematic investigation of spatial asymmetries in the impactor rate of micrometeoroids over Mercury's surface as a function of planetary true anomaly (TAA). Since the orbit of Mercury is quite eccentric a seasonal variation of the impact rate is to be expected. We find that the source peaks near the planetary equator for most TAA. Contrary to previous assumptions, we find the source to be non-uniform in local time. Only certain regions of Mercury are exposed to dust as a result of the orbital elements of Mercury and of the Main Belt particles (inclination less than 20°). Our results offer important constraints on transport models used for interpreting measurements of this exosphere, but also inform studies of space weathering of Mercury's surface.

  17. Value, obligation and the asymmetry question.

    PubMed

    Tooley, Michael

    1998-04-01

    Is there a prima facie obligation to produce additional individuals whose lives would be worth living? In his paper 'Is it good to make happy people?', Stuart Rachels argues not only that there is, but, also, that precisely as much weight should be assigned to the quality of life that would be enjoyed by such potential persons, if they were to be actualized, as to the quality of life enjoyed by actually existing persons. In response, I shall argue, first, that Rachels' view is exposed to very serious objections, and secondly, that his arguments in support of his position involve a crucial assumption, which cannot be sustained, concerning the relation between, on the one hand, propositions about good-making and bad-making properties, and, on the other, propositions about right-making and wrong-making ones. I shall then argue that there is a very plausible position concerning the conditions under which an action can be morally wrong which entails the following asymmetry: there is a prima facie obligation not to bring into existence individuals whose lives are not worth living, but there is no corresponding obligation to create additional individuals whose lives would be worth living. PMID:11655328

  18. Experimental investigations of the Electrical Asymmetry Effect

    NASA Astrophysics Data System (ADS)

    Schulze, Julian; Schuengel, Edmund; Luggenhoelscher, Dirk; Czarnetzki, Uwe; Donko, Zoltan

    2009-10-01

    In 2008 a method to generate a variable DC self bias even in geometrically symmetric capacitively coupled radio frequency (CCRF) discharges was proposed theoretically [1]. If the discharge is operated at a fundamental frequency and its second harmonic, it has been predicted that the resulting DC self bias can be adjusted by the phase angle between the applied voltage harmonics. A PIC simulation demonstrated that this Electrical Asymmetry Effect (EAE) allows separate control of the energy and flux of ions at the electrode surfaces. Here the EAE and the related separate control of ion energy and flux is investigated experimentally in a geometrically symmetric CCRF discharge operated at 13.56 MHz and 27.12 MHz with variable phase shift between the harmonics in argon at different pressures. The DC self bias, the energy as well as the flux of ions at the grounded electrode are measured. The experimental results verify the theoretical predictions and show that ion energy and flux can be controlled separately. The EAE is optimized by choosing low and high frequency voltage amplitudes that yield the strongest relative DC self bias. [4pt] [1] Heil B G et al. 2008 J. Phys. D 41 165202

  19. Lepton asymmetry from mixing and oscillations

    NASA Astrophysics Data System (ADS)

    Kartavtsev, A.; Millington, P.; Vogel, H.

    2016-06-01

    We show how the two physically-distinct sources of CP -asymmetry relevant to scenarios of leptogenesis: (i) resonant mixing and (ii) oscillations between different flavours can be unambiguously identified within the Kadanoff-Baym formalism. These contributions are isolated by analyzing the spectral structure of the non-equilibrium propagators without relying on the definition of particle number densities. The mixing source is associated with the usual mass shells, whereas the oscillation source is identified with a third intermediate shell. In addition, we identify terms lying on the oscillation shell that can be interpreted as the destructive interference between mixing and oscillation. We confirm that identical shell structure is obtained in both the Heisenberg- and interaction-picture realizations of the Kadanoff-Baym formalism. In so doing, we illustrate the self-consistency and complementarity of these two approaches. The interaction-picture approach in particular has the advantage that it may be used to analyze all forms of mass spectra from quasi-degenerate through to hierarchical.

  20. Visual field asymmetries in visual evoked responses

    PubMed Central

    Hagler, Donald J.

    2014-01-01

    Behavioral responses to visual stimuli exhibit visual field asymmetries, but cortical folding and the close proximity of visual cortical areas make electrophysiological comparisons between different stimulus locations problematic. Retinotopy-constrained source estimation (RCSE) uses distributed dipole models simultaneously constrained by multiple stimulus locations to provide separation between individual visual areas that is not possible with conventional source estimation methods. Magnetoencephalography and RCSE were used to estimate time courses of activity in V1, V2, V3, and V3A. Responses to left and right hemifield stimuli were not significantly different. Peak latencies for peripheral stimuli were significantly shorter than those for perifoveal stimuli in V1, V2, and V3A, likely related to the greater proportion of magnocellular input to V1 in the periphery. Consistent with previous results, sensor magnitudes for lower field stimuli were about twice as large as for upper field, which is only partially explained by the proximity to sensors for lower field cortical sources in V1, V2, and V3. V3A exhibited both latency and amplitude differences for upper and lower field responses. There were no differences for V3, consistent with previous suggestions that dorsal and ventral V3 are two halves of a single visual area, rather than distinct areas V3 and VP. PMID:25527151

  1. Functional chiral asymmetry in descending thoracic aorta.

    PubMed

    Frazin, L J; Lanza, G; Vonesh, M; Khasho, F; Spitzzeri, C; McGee, S; Mehlman, D; Chandran, K B; Talano, J; McPherson, D

    1990-12-01

    To determine whether rotational blood flow or chiral asymmetry exists in the human descending thoracic aorta, we established the ability of color Doppler ultrasound to detect rotational flow in a tornado tube model of a vortex descending fluid column. In a model of the human aortic arch with a pulse duplicator, color Doppler was then used to demonstrate that rotational flow occurs first in the transverse arch and then in the proximal descending thoracic aorta. With the use of color Doppler esophageal echocardiography, 53 patients (age range, 25-78 years; mean age, 56.4 years) were prospectively examined for rotational flow in the descending thoracic aorta. At 10 cm superior to retro-left ventricular position, 22 of 38 patients (58%) revealed rotational flow with obvious diastolic counterclockwise rotation but less obvious systolic clockwise rotation. At 5 cm superior to retro-left ventricular position, 29 of 46 patients (63%) revealed rotational flow with a tendency toward systolic clockwise and diastolic counterclockwise rotation. At the retro-left ventricular position, 47 of 53 patients (89%) revealed rotational flow, usually of a clockwise direction, occurring in systole. Our data suggest that aortic flow is not purely pulsatile and axial but has a rotational component. Rotational flow begins in the aortic arch and is carried through to the descending thoracic aorta, where flow is chirally asymmetric with systolic clockwise and diastolic counterclockwise components. These data demonstrate an aortic rotational flow component that may have physiological implications for organ perfusion. PMID:2242523

  2. Amplitude and polarization asymmetries in a ring laser

    NASA Technical Reports Server (NTRS)

    Campbell, L. L.; Buholz, N. E.

    1971-01-01

    Asymmetric amplitude effects between the oppositely directed traveling waves in a He-Ne ring laser are analyzed both theoretically and experimentally. These effects make it possible to detect angular orientations of an inner-cavity bar with respect to the plane of the ring cavity. The amplitude asymmetries occur when a birefringent bar is placed in the three-mirror ring cavity, and an axial magnetic field is applied to the active medium. A simplified theoretical analysis is performed by using a first order perturbation theory to derive an expression for the polarization of the active medium, and a set of self-consistent equations are derived to predict threshold conditions. Polarization asymmetries between the oppositely directed waves are also predicted. Amplitude asymmetries similar in nature to those predicted at threshold occur when the laser is operating in 12-15 free-running modes, and polarization asymmetry occurs simultaneously.

  3. Cerebral blood flow asymmetries in headache-free migraineurs

    SciTech Connect

    Levine, S.R.; Welch, K.M.; Ewing, J.R.; Joseph, R.; D'Andrea, G.

    1987-11-01

    Regional cerebral blood flow (rCBF) asymmetries were studied in controls and patients with common and classic/complicated migraine using /sup 133/Xe inhalation with 8 homologously situated external collimators over each cerebral hemisphere. Migraine patients as a group more frequently had posterior rCBF asymmetries than controls (p less than 0.03). Although there were no differences in the number of anterior rCBF asymmetries, migraine patients had 2 or more asymmetric probe pairs more often than controls (p less than 0.02). The posterior rCBF asymmetries, consistent with the site of activation of many migraine attacks, may be related to more labile control of the cerebral circulation.

  4. The small scale power asymmetry in the cosmic microwave background

    SciTech Connect

    Flender, Samuel; Hotchkiss, Shaun E-mail: shaun.hotchkiss@helsinki.fi

    2013-09-01

    We investigate the hemispherical power asymmetry in the cosmic microwave background on small angular scales. We find an anomalously high asymmetry in the multipole range l = 601−2048, with a naive statistical significance of 6.5σ. However, we show that this extreme anomaly is simply a coincidence of three other effects, relativistic power modulation, edge effects from the mask applied, and inter-scale correlations. After correcting for all of these effects, the significance level drops to ∼ 1σ, i.e., there is no anomalous intrinsic asymmetry in the small angular scales. Using this null result, we derive a constraint on a potential dipolar modulation amplitude, A(k) < 0.0045 on the ∼ 10 Mpc-scale, at 95% C.L. This new constraint must be satisfied by any theoretical model attempting to explain the hemispherical asymmetry at large angular scales.

  5. Cosmological matter-antimatter asymmetry as a quantum fluctuation

    NASA Astrophysics Data System (ADS)

    Kobakhidze, Archil; Manning, Adrian

    2015-06-01

    We entertain a new paradigm according to which the observed matter-antimatter asymmetry is generated as a large-scale quantum fluctuation over the baryon-symmetric state that occurred during the cosmic inflation.

  6. Time-integrated charge asymmetries at D0

    SciTech Connect

    Cheu, E.; /Arizona U.

    2006-10-01

    We have measured the time-integrated charge asymmetries in dimuon events and semileptonic B{sub s} decays. These results are the most precise semileptonic charge asymmetries in B decays to date. We combine these results with measurements from the decay B{sub s} {yields} J/{psi}{phi} to determine the CP-violating phase {phi}{sub s}. They find {phi}{sub s} = -0.56{sub -0.41}{sup +0.44}.

  7. Unpolarized Azimuthal Asymmetries from the COMPASS Experiment at CERN

    SciTech Connect

    Joosten, Rainer

    2009-12-17

    Azimuthal asymmetries in unpolarized SIDIS can be used to probe the transverse momentum of the quarks inside the nucleon. Furthermore, they give access to the so-far unmeasured Boer-Mulders function. In this contribution, results on these asymmetries, extracted separately for positive and negative hadrons, from the COMPASS data taken with a 160 GeV/c {mu}{sup +} beam on a deuteron target will be reported and compared to theoretical predictions.

  8. Azimuthal asymmetries in DVCS on unpolarized hydrogen and deuterium targets

    SciTech Connect

    Marukyan, H.

    2009-08-04

    We report the latest results of azimuthal asymmetries in the DVCS process measured at the HERMES experiment on unpolarized hydrogen and deuterium targets. Exploiting the ability of HERA to provide lepton beams with both charges and spin orientations, it is possible to extract simultaneously asymmetry amplitudes attributed to the pure DVCS process and to the interference between the Bethe-Heitler and DVCS processes. The results are compared to the theoretical calculations.

  9. Tuning piezoresistive transduction in nanomechanical resonators by geometrical asymmetries

    SciTech Connect

    Llobet, J.; Sansa, M.; Lorenzoni, M.; Pérez-Murano, F.; Borrisé, X.; San Paulo, A.

    2015-08-17

    The effect of geometrical asymmetries on the piezoresistive transduction in suspended double clamped beam nanomechanical resonators is investigated. Tapered silicon nano-beams, fabricated using a fast and flexible prototyping method, are employed to determine how the asymmetry affects the transduced piezoresistive signal for different mechanical resonant modes. This effect is attributed to the modulation of the strain in pre-strained double clamped beams, and it is confirmed by means of finite element simulations.

  10. Craniofacial Asymmetry in Adults With Neglected Congenital Muscular Torticollis

    PubMed Central

    Jeong, Kil-Yong; Min, Kyung-Jay; Woo, Jieun

    2015-01-01

    Objective To evaluate the craniofacial asymmetry in adults with neglected congenital muscular torticollis (CMT) by quantitative assessment based on craniofacial three-dimensional computed tomography (3D-CT). Methods Preoperative craniofacial asymmetry was measured by 3D-CT for 31 CMT subjects ≥18 years of age who visited a tertiary medical center and underwent 3D-CT between January 2009 and December 2013. The relationship between the age and the severity of craniofacial asymmetry was analyzed in reference to anteroposterior length asymmetry of the frontal bone and zygomatic arch, vertical and lateral displacements of the facial landmarks, and mandibular axis rotation. Results The age at CT was 27.71±7.02 years (range, 18-44 years). All intra-class correlation coefficients were higher than 0.7, suggesting good inter-rater reliability (p<0.05) of all the measurements. The frontal and the zygomatic length ratio (i.e., the anteroposterior length asymmetry on the axial plane) was 1.06±0.03 and 1.07±0.03, respectively, which was increased significantly with age in the linear regression analysis (r2=0.176, p=0.019 and r2=0.188, p=0.015, respectively). The vertical or lateral displacement of the facial landmarks and rotation of the mandibular axis did not significantly correlate with age (p>0.05). Conclusion Craniofacial asymmetry of neglected CMT became more severe with age in terms of anteroposterior length asymmetry of the ipsilateral frontal bone and zygomatic arch on the axial plane even after growth cessation. This finding may enhance the understanding of therapeutic strategies for craniofacial asymmetry in adults with neglected CMT. PMID:26161351

  11. Tuning piezoresistive transduction in nanomechanical resonators by geometrical asymmetries

    NASA Astrophysics Data System (ADS)

    Llobet, J.; Sansa, M.; Lorenzoni, M.; Borrisé, X.; San Paulo, A.; Pérez-Murano, F.

    2015-08-01

    The effect of geometrical asymmetries on the piezoresistive transduction in suspended double clamped beam nanomechanical resonators is investigated. Tapered silicon nano-beams, fabricated using a fast and flexible prototyping method, are employed to determine how the asymmetry affects the transduced piezoresistive signal for different mechanical resonant modes. This effect is attributed to the modulation of the strain in pre-strained double clamped beams, and it is confirmed by means of finite element simulations.

  12. MESSENGER Observations of Asymmetries at Mercury's Magnetotail Current Sheet

    NASA Astrophysics Data System (ADS)

    Poh, Gangkai; Slavin, James; Jia, Xianzhe; Raines, Jim; Sun, Wei-Jie; Genestreti, Kevin; Smith, Andy; Gershman, Daniel; Anderson, Brian

    2016-04-01

    Dawn-dusk asymmetries in the Earth's magnetotail current sheet have been observed and remain an active area of research. With an internal magnetic dipole field structure similar to Earth's, similar dawn-dusk asymmetries might be expected in Mercury's magnetotail current sheet. However, no observation of dawn-dusk asymmetries has been reported in the structure of Mercury's magnetotail. Using 4 years of MESSENGER's magnetic field and plasma data, we analyzed 319 current sheet crossings. From the polarity of Bz in the cross-tail current sheet, we determined that MESSENGER is on closed field lines about 90% of the time. During the other 10% MESSENGER observed negative Bz indicating that it was tailward of the Near Mercury Neutral Line (NMNL). The Bz magnetic field is also observed to be higher at the dawnside than the duskside of the magnetotail current sheet by approximately a factor of three. Further the asymmetry decreases with increasing downstream distance. A reduction (enhancement) in Bz should correspond to a more (less) stretched and thinned (thickened) current sheet. Analysis of current sheet thickness based upon MESSENGER's observations confirms this behavior with mean current sheet thickness and Bz intensity having dawn-dusk asymmetries with the same sense. Plasma β in the current sheet also exhibits a dawn-dusk asymmetry opposite to that of Bz. This is consistent with expectations based on MHD stress balance. Earlier studies had shown a dawn-dusk asymmetry in the heavy ion in Mercury's magnetotail. We suggest that this enhancement of heavy ions in the duskside current sheet, due to centrifugal acceleration of ions from the cusp and gradient-curvature drift from the NMNL, may provide a partial explanation of the dawn-dusk current sheet asymmetries found in this study.

  13. Strangeness asymmetry of the nucleon in the statistical parton model

    NASA Astrophysics Data System (ADS)

    Bourrely, Claude; Soffer, Jacques; Buccella, Franco

    2007-04-01

    We extend to the strange quarks and antiquarks, the statistical approach of parton distributions and we calculate the strange quark asymmetry s -sbar. We find that the asymmetry is small, positive in the low x region and negative in the high x region. In this framework, the polarized strange quarks and antiquarks distributions, which are obtained simultaneously, are found to be both negative for all x values.

  14. Sound attenuation characteristics of cellular metamaterials

    NASA Astrophysics Data System (ADS)

    Varanasi, Satya Surya Srinivas

    The objectives of this work were to develop lightweight barrier and compact absorbing material systems for controlling low frequency noise (say below 2 kHz). The solutions explored fell into the broad category of segmented cellular materials in which local resonances are built-in attributes. The body of the work was divided into four parts. First, a cellular metamaterial concept for lightweight barrier materials was proposed, then, secondly, the concept was experimentally verified by testing application-scale designs in a diffuse sound field setup. In the remaining two parts of the work, the idea of shifting sound energy emporally and spatially was explored as a means of improving the performance of metamaterial-based barrier solutions and of compact sound absorbers, respectively. The high sound transmission loss (STL) metamaterials described to-date commonly require the introduction of relatively heavy resonating or constraining components which runs counter to the desire to create lightweight barrier solutions. It was proposed here that a cellular panel comprising a periodic arrangement of unit cells consisting of plates held in a grid-like frame, which itself is unsupported, can possess a high STL within a specified frequency range without an undue mass penalty. It was numerically demonstrated that such a cellular panel can yield enhanced STL if the unit cell mass is apportioned appropriately between the unit cell plate and the surrounding grid-like frame. The concept of planar cellular metamaterials was verified through diffuse field experiments on application-scale specimens by using intensity methods. Two cellular panel designs were tested and their behavior was compared with that of a reference limp panel. It was found that the predicted benefit of the cellular panels could be realized by increasing the mass contrast in the designs, and that the benefit was reduced with increasing diffuseness of the sound field. It was also found that the loss in performance

  15. Characterization of Asymmetry in Magnetoacoustic Emission Burst by Numerical Processes

    NASA Technical Reports Server (NTRS)

    Namkung, M.; Fulton, J. P.; Wincheski, B.; DeNale, R.

    1991-01-01

    It has been well known that the pattern of the magnetoacoustic emission (MAE) burst observed during the sweep over one half-cycle of the hysteresis loop becomes asymmetric depending on the strength of the magnetic domain wall-defect interaction and the state of residual stresses in a ferromagnet. The ascending asymmetry due to the former has been observed at a very low frequency (.7 Hz) of applied AC magnetic field at a given amplitude. The descending asymmetry due to uniaxial compressive stress has been typically observed at the AC applied magnetic field frequency of 20 Hz. The physical interpretation of both types of asymmetry has been well established. It is, however, necessary to perform investigations of the dependence of asymmetry on externally controlled parameters such as the amplitude and frequency of the AC applied magnetic fields. The purpose of the present study is therefore to devise a mathematical means that describes the degree of asymmetry of the MAE burst and apply this scheme to investigate the AC magnetic field amplitude dependence of the asymmetry.

  16. Generation of a global longitudinal asymmetry in Saturn's magnetosphere

    NASA Astrophysics Data System (ADS)

    Hill, T. W.; Jaggi, A.; Wolf, R.; Sazykin, S. Y.

    2014-12-01

    Numerous empirical studies have indicated that a global longitudinal asymmetry of Saturn's magnetospheric plasma population (the m=1 term in a Fourier expansion, where m is the azimuthal wavenumber) is required to explain observed spin-periodic modulations (~ 10.7 hr) of magnetospheric behavior (e.g., Carbary and Mitchell [2013], Rev. Geophys., 51, doi:10.1029/2012RG000416, and references therein). This is true in spite of the fact that Saturn's intrinsic magnetic field is well described by a perfectly spin-aligned dipole. The Rice Convection Model (RCM) has been used previously to simulate plasma transport in Saturn's magnetosphere with a spin-aligned dipole field and a longitudinally symmetric plasma source that is largely confined to the radial range L ~ 5 - 8 (e.g., Liu et al. [2010], J. Geophys. Res., 115, doi:10.1029/2010JA015859; Liu and Hill [2012], J. Geophys. Res., 117, doi:10.1029/2012JA017827). We have begun to explore the consequences of a global-scale longitudinal asymmetry of the plasma source. Preliminary results indicate that a small (~1%) asymmetry of the imposed plasma source produces a magnetospherically significant (factor ~2) m=1 asymmetry of the resultant plasma distribution in the middle magnetosphere (L ~ 8-15). Our objective is not to explain the (still mysterious) underlying cause of the source asymmetry, but rather to investigate the effects of a given source asymmetry on the plasma distribution in the more distant magnetosphere.

  17. The validity of individual frontal alpha asymmetry EEG neurofeedback.

    PubMed

    Quaedflieg, C W E M; Smulders, F T Y; Meyer, T; Peeters, F; Merckelbach, H; Smeets, T

    2016-01-01

    Frontal asymmetry in alpha oscillations is assumed to be associated with psychopathology and individual differences in emotional responding. Brain-activity-based feedback is a promising tool for the modulation of cortical activity. Here, we validated a neurofeedback protocol designed to change relative frontal asymmetry based on individual alpha peak frequencies, including real-time average referencing and eye-correction. Participants (N = 60) were randomly assigned to a right, left or placebo neurofeedback group. Results show a difference in trainability between groups, with a linear change in frontal alpha asymmetry over time for the right neurofeedback group during rest. Moreover, the asymmetry changes in the right group were frequency and location specific, even though trainability did not persist at 1 week and 1 month follow-ups. On the behavioral level, subjective stress on the second test day was reduced in the left and placebo neurofeedback groups, but not in the right neurofeedback group. We found individual differences in trainability that were dependent on training group, with participants in the right neurofeedback group being more likely to change their frontal asymmetry in the desired direction. Individual differences in trainability were also reflected in the ability to change frontal asymmetry during the feedback. PMID:26163671

  18. Gaussian quantum steering and its asymmetry in curved spacetime

    NASA Astrophysics Data System (ADS)

    Wang, Jieci; Cao, Haixin; Jing, Jiliang; Fan, Heng

    2016-06-01

    We study Gaussian quantum steering and its asymmetry in the background of a Schwarzschild black hole. We present a Gaussian channel description of quantum state evolution under the influence of Hawking radiation. We find that thermal noise introduced by the Hawking effect will destroy the steerability between an inertial observer Alice and an accelerated observer Bob who hovers outside the event horizon, while it generates steerability between Bob and a hypothetical observer anti-Bob inside the event horizon. Unlike entanglement behaviors in curved spacetime, here the steering from Alice to Bob suffers from a "sudden death" and the steering from anti-Bob to Bob experiences a "sudden birth" with increasing Hawking temperature. We also find that the Gaussian steering is always asymmetric and the maximum steering asymmetry cannot exceed ln 2 , which means the state never evolves to an extremal asymmetry state. Furthermore, we obtain the parameter settings that maximize steering asymmetry and find that (i) s =arccosh cosh/2r 1 -sinh2r is the critical point of steering asymmetry and (ii) the attainment of maximal steering asymmetry indicates the transition between one-way steerability and both-way steerability for the two-mode Gaussian state under the influence of Hawking radiation.

  19. Radial and longitudinal asymmetry of human pharyngeal pressures during swallowing.

    PubMed

    Sears, V W; Castell, J A; Castell, D O

    1991-12-01

    Radial asymmetry of upper esophageal sphincter resting pressure has been previously described; however, neither radial nor longitudinal asymmetry of pharyngeal pressures has been demonstrated. The authors used a specially designed intraluminal transducer catheter (Konigsberg; Konigsberg Instruments, Pasadena, CA) with four solid-state transducers separated by 3 cm and oriented circumferentially at 90 degrees intervals to measure pharyngeal pressures. Two wet swallows at each 1-cm interval along the length of the pharynx were measured in 12 normal volunteers (10 male, 2 female; mean age, 38 years). Pressure data were collected on-line by an Apple IIe microcomputer (Apple Computer Inc., Cupertino, CA) at 100 Hz and analyzed for both radial and longitudinal asymmetry. Significant (P less than 0.05) longitudinal asymmetry was shown in all positions except right lateral. Radial asymmetry was present for the first 4 cm only, with anterior and posterior pressures significantly (P less than 0.05) higher than lateral pressures. It was concluded that pharyngeal pressure responses show both axial and longitudinal asymmetry in the distal pharynx. Awareness of transducer position and orientation is essential in the evaluation of pharyngeal pressures. PMID:1955121

  20. Effects of Convective Asymmetries on Hurricane Intensity: A Numerical Study

    NASA Technical Reports Server (NTRS)

    Wu, Liguang; Braun, Scott A.

    2003-01-01

    The influence of the uniform large-scale flow, beta effect, and vertical shear of the environmental flow on hurricane intensity is investigated in the context of the induced convective or potential vorticity asymmetries with a hydrostatic primitive equation hurricane model. In agreement with the previous studies, imposing of one of these environmental effects can substantially weaken the simulated tropical cyclones. In response t o the environmental influence, significant asymmetries develop with a structure similar to the spiral bands in real hurricanes, which are dominated by wavenumber-one components. The tendencies of the mean radial, azimuthal winds and temperature associated with the environment-induced convective asymmetries are evaluated respectively. The resulting asymmetries can effectively reduce hurricane intensity by directly producing the negative tendency of the mean tangential wind in the vicinity of the radius of maximum wind, and by weakening the mean radial circulation. The reduction effects are closely associated with the spiral structure of the induced asymmetries. The time lag observed between the imposition of the environmental influence and the resulting rise in the minimum central pressure is the time required for developing the spiral structure. This study also confirms the axisymmetrization process associated with the induced wavenumber-one components of potential vorticity asymmetries, but it exists only within the radius of maximum wind.

  1. Thalamic control of sensory selection in divided attention

    PubMed Central

    Wimmer, Ralf D.; Schmitt, L. Ian; Davidson, Thomas J.; Nakajima, Miho; Deisseroth, Karl; Halassa, Michael M.

    2015-01-01

    How the brain selects appropriate sensory inputs and suppresses distractors is a central unsolved mystery in neuroscience. Given the well-established role of prefrontal cortex (PFC) in executive function1, its interactions with sensory cortical areas during attention have been hypothesized to control sensory selection2–5. To test this idea and more generally dissect the circuits underlying sensory selection, we developed a cross-modal divided attention task in mice enabling genetic access to this cognitive process. By optogenetically perturbing PFC function in a temporally-precise window, the ability of mice to appropriately select between conflicting visual and auditory stimuli was diminished. Surprisingly, equivalent sensory thalamo-cortical manipulations showed that behavior was causally dependent on PFC interactions with sensory thalamus, not cortex. Consistent with this notion, we found neurons of the visual thalamic reticular nucleus (visTRN) to exhibit PFC-dependent changes in firing rate predictive of the modality selected. visTRN activity was causal to performance as confirmed via subnetwork-specific bi-directional optogenetic manipulations. Through a combination of electrophysiology and intracellular chloride photometry, we demonstrated that visTRN dynamically controls visual thalamic gain through feedforward inhibition. Combined, our experiments introduce a new subcortical model of sensory selection, where prefrontal cortex biases thalamic reticular subnetworks to control thalamic sensory gain, selecting appropriate inputs for further processing. PMID:26503050

  2. Disability Divides in India: Evidence from the 2011 Census

    PubMed Central

    Saikia, Nandita; Bora, Jayanta Kumar; Jasilionis, Domantas; Shkolnikov, Vladimir M.

    2016-01-01

    Background Understanding the socioeconomic and regional divides in disability prevalence in India has considerable relevance for designing public health policies and programs. Objectives The aim of the present study is to quantify the prevalence of disability by gender, region (rural and urban; states and districts), and caste. We also examine the association between disability prevalence and the major socio-demographic and socioeconomic characteristics of the districts in India. Methods Age-standardized disability prevalence (ASDP) was calculated using 2011 census data and applying the WHO World Standard Population. A regression analysis was carried out to examine the association between disability prevalence and demographic and socioeconomic characteristics across districts of India. Results The study found that ASDP varies substantially across districts and is higher among women, rural dwellers, and members of scheduled tribes (STs) and scheduled castes (SCs). The regression model showed that the disability rate in districts rises with increasing proportions of the population who are urban dwellers, aged 65 or older, members of STs, and living in dilapidated housing; and that the disability prevalence decreases with increasing proportions of the female population who are literate, and of the general population who are working and have access to safe drinking water. Conclusion As the burden of disability falls disproportionately across geographic regions and socioeconomic groups, public health policies in India should take this variation into account. The definition of disability used in the census should be modified to generate internationally comparable estimates of disability prevalence. PMID:27490469

  3. Cytoplasmic streaming direction reverses in dividing Paramecium bursaria.

    PubMed

    Sikora, J; Wasik, A; Zajaczkowska, M

    1991-11-29

    Using the interference-contrast videomicroscopy the speed of cytoplasmic streaming was measured during the sequence of division stages in thigmotactically settled specimens of Paramecium bursaria. The speed of cytoplasmic flow gradually decreased during the first stages of binary fission and movement became indistinguishable at stage D(3). Almost at the same time cytoplasm started to move in the opposite direction, pushing or pulling the dividing micronucleus into the prospective posterior daughter cell and eventually stopped at stage D(5)-D(6). Further cell division events proceeded without detectable movement of cytoplasmic components. Cytoplasmic streaming in the normal interphase route was gradually restored in daughter cells about 30-40 min after cell separation. During the whole period of binary fission phagocytosis was arrested. Transportation and participation in the positioning of prospective micronuclei in daughter cells seems to be the main function of cytoplasmic streaming activity in cell division of Paramecium bursaria. The possible relationship between the stages of cytoskeleton transitions and the kinetics of cytoplasmic streaming associated with cell divison is discussed. PMID:23194845

  4. Flood variability east of Australia’s Great Dividing Range

    NASA Astrophysics Data System (ADS)

    Rustomji, Paul; Bennett, Neil; Chiew, Francis

    2009-08-01

    SummaryThe variability of flow in river channels influences the spatial and temporal variability of many biophysical processes including the transport of sediment and waterborne pollutants and the recruitment of aquatic animals and plants. In this study, inter- and intra-basin patterns of flood variability are examined for catchments east of Australia's Great Dividing Range. Three measures of flood variability are explored with uncertainty quantified using bootstrap resampling. The two preferred measures of flood variability (namely a flood quantile ratio and a power law scaling coefficient) produced similar results. Catchments in the wet tropics of far north Queensland experience low flood variability. Flood variability increased southwards through Queensland, reaching a maximum in the vicinity of the Fitzroy and Burnett River basins. The small near-coast catchments of southern Queensland and northern New Wales experience low flood variability. Flood variability is also high in the southern Hunter River and Hawkesbury-Nepean basins. Using L-moment ratio diagrams with data from 424 streamflow stations, we also conclude that the Generalised Pareto distribution is preferable for modelling flood frequency curves for this region. These results provide a regional perspective that can be used to develop new hypotheses about the effects of hydrologic variability on the biophysical characteristics of these Australian rivers.

  5. Two-Volt Josephson Arbitrary Waveform Synthesizer Using Wilkinson Dividers

    PubMed Central

    Flowers-Jacobs, Nathan E.; Fox, Anna E.; Dresselhaus, Paul D.; Schwall, Robert E.; Benz, Samuel P.

    2016-01-01

    The root-mean-square (rms) output voltage of the NIST Josephson arbitrary waveform synthesizer (JAWS) has been doubled from 1 V to a record 2 V by combining two new 1 V chips on a cryocooler. This higher voltage will improve calibrations of ac thermal voltage converters and precision voltage measurements that require state-of-the-art quantum accuracy, stability, and signal-to-noise ratio. We achieved this increase in output voltage by using four on-chip Wilkinson dividers and eight inner-outer dc blocks, which enable biasing of eight Josephson junction (JJ) arrays with high-speed inputs from only four high-speed pulse generator channels. This approach halves the number of pulse generator channels required in future JAWS systems. We also implemented on-chip superconducting interconnects between JJ arrays, which reduces systematic errors and enables a new modular chip package. Finally, we demonstrate a new technique for measuring and visualizing the operating current range that reduces the measurement time by almost two orders of magnitude and reveals the relationship between distortion in the output spectrum and output pulse sequence errors. PMID:27453676

  6. Network color management system using a cluster dividing method

    NASA Astrophysics Data System (ADS)

    Nichogi, Mutsuko; Kanamori, Katsuhiro

    2001-12-01

    Recently the color reproduction of the real objects is becoming more and more important in the field of telemedicine and internet shopping. To reproduce the object's color under the various conditions, the surface spectral reflectance has to be estimated. In this paper we present the novel way to estimate it using conventional 3- band digital camera. Usually the precise estimation of the spectra from the 3-band image is very difficult, as it has metameric black and the simple camera model is not suitable. To improve the estimation accuracy, we propose dividing color space in to clusters and estimating spectra using different model parameters at each cluster. Clusters are set corresponding to the major objects in camera images. Next the estimated spectral image is reproduced on the monitor. When luminance and color temperature of the specified viewing illuminant and the monitor are different, the subject hardly perceives the object's real color. Therefore the image is converted using CIECAM97s. This paper shows the results of simulation using the image of enlarged human's mouth assuming remote consulting with dental clinic. In this system, a dentist can perceive the real color of patient's gums and teeth on the monitor.

  7. Movement Synchrony Forges Social Bonds across Group Divides

    PubMed Central

    Tunçgenç, Bahar; Cohen, Emma

    2016-01-01

    Group dynamics play an important role in the social interactions of both children and adults. A large amount of research has shown that merely being allocated to arbitrarily defined groups can evoke disproportionately positive attitudes toward one's in-group and negative attitudes toward out-groups, and that these biases emerge in early childhood. This prompts important empirical questions with far-reaching theoretical and applied significance. How robust are these inter-group biases? Can biases be mitigated by behaviors known to bond individuals and groups together? How can bonds be forged across existing group divides? To explore these questions, we examined the bonding effects of interpersonal synchrony on minimally constructed groups in a controlled experiment. In-group and out-group bonding were assessed using questionnaires administered before and after a task in which groups performed movements either synchronously or non-synchronously in a between-participants design. We also developed an implicit behavioral measure, the Island Game, in which physical proximity was used as an indirect measure of interpersonal closeness. Self-report and behavioral measures showed increased bonding between groups after synchronous movement. Bonding with the out-group was significantly higher in the condition in which movements were performed synchronously than when movements were performed non-synchronously between groups. The findings are discussed in terms of their importance for the developmental social psychology of group dynamics as well as their implications for applied intervention programs. PMID:27303341

  8. Effects of Divided Attention at Retrieval on Conceptual Implicit Memory

    PubMed Central

    Prull, Matthew W.; Lawless, Courtney; Marshall, Helen M.; Sherman, Annabella T. K.

    2016-01-01

    This study investigated whether conceptual implicit memory is sensitive to process-specific interference at the time of retrieval. Participants performed the implicit memory test of category exemplar generation (CEG; Experiments 1 and 3), or the matched explicit memory test of category-cued recall (Experiment 2), both of which are conceptually driven memory tasks, under one of two divided attention (DA) conditions in which participants simultaneously performed a distracting task. The distracting task was either syllable judgments (dissimilar processes), or semantic judgments (similar processes) on unrelated words. Compared to full attention (FA) in which no distracting task was performed, DA had no effect on CEG priming overall, but reduced category-cued recall similarly regardless of distractor task. Analyses of distractor task performance also revealed differences between implicit and explicit memory retrieval. The evidence suggests that, whereas explicit memory retrieval requires attentional resources and is disrupted by semantic and phonological distracting tasks, conceptual implicit memory is automatic and unaffected even when distractor and memory tasks involve similar processes. PMID:26834678

  9. MSAT and cellular hybrid networking

    NASA Technical Reports Server (NTRS)

    Baranowsky, Patrick W., II

    1993-01-01

    Westinghouse Electric Corporation is developing both the Communications Ground Segment and the Series 1000 Mobile Phone for American Mobile Satellite Corporation's (AMSC's) Mobile Satellite (MSAT) system. The success of the voice services portion of this system depends, to some extent, upon the interoperability of the cellular network and the satellite communication circuit switched communication channels. This paper will describe the set of user-selectable cellular interoperable modes (cellular first/satellite second, etc.) provided by the Mobile Phone and described how they are implemented with the ground segment. Topics including roaming registration and cellular-to-satellite 'seamless' call handoff will be discussed, along with the relevant Interim Standard IS-41 Revision B Cellular Radiotelecommunications Intersystem Operations and IOS-553 Mobile Station - Land Station Compatibility Specification.

  10. The influence of the secondary electron induced asymmetry on the electrical asymmetry effect in capacitively coupled plasmas

    NASA Astrophysics Data System (ADS)

    Korolov, Ihor; Derzsi, Aranka; Donkó, Zoltán; Schulze, Julian

    2013-08-01

    In geometrically symmetric capacitive radio-frequency plasmas driven by two consecutive harmonics, a dc self-bias can be generated as a function of the phase shift between the driving frequencies via the Electrical Asymmetry Effect (EAE). Recently, the Secondary Electron Asymmetry Effect (SEAE) was discovered (Lafleur et al., J. Phys. D: Appl. Phys. 46, 135201 (2013)): unequal secondary electron emission coefficients at both electrodes were found to induce an asymmetry in single-frequency capacitive plasmas. Here, we investigate the simultaneous presence of both effects, i.e., a dual-frequency plasma driven by two consecutive harmonics with different electrode materials. We find that the superposition of the EAE and the SEAE is generally non-linear, i.e., the asymmetries generated by each individual effect do not simply add up at all phases. The control ranges of the dc self-bias and the mean ion energy can be enlarged, if both effects are combined.

  11. The influence of the secondary electron induced asymmetry on the electrical asymmetry effect in capacitively coupled plasmas

    SciTech Connect

    Korolov, Ihor; Derzsi, Aranka; Donkó, Zoltán; Schulze, Julian

    2013-08-05

    In geometrically symmetric capacitive radio-frequency plasmas driven by two consecutive harmonics, a dc self-bias can be generated as a function of the phase shift between the driving frequencies via the Electrical Asymmetry Effect (EAE). Recently, the Secondary Electron Asymmetry Effect (SEAE) was discovered (Lafleur et al., J. Phys. D: Appl. Phys. 46, 135201 (2013)): unequal secondary electron emission coefficients at both electrodes were found to induce an asymmetry in single-frequency capacitive plasmas. Here, we investigate the simultaneous presence of both effects, i.e., a dual-frequency plasma driven by two consecutive harmonics with different electrode materials. We find that the superposition of the EAE and the SEAE is generally non-linear, i.e., the asymmetries generated by each individual effect do not simply add up at all phases. The control ranges of the dc self-bias and the mean ion energy can be enlarged, if both effects are combined.

  12. Beyond annexin V: fluorescence response of cellular membranes to apoptosis.

    PubMed

    Demchenko, Alexander P

    2013-03-01

    Dramatic changes in the structure of cell membranes on apoptosis allow easy, sensitive and non-destructive analysis of this process with the application of fluorescence methods. The strong plasma membrane asymmetry is present in living cells, and its loss on apoptosis is commonly detected with the probes interacting strongly and specifically with phosphatidylserine (PS). This phospholipid becomes exposed to the cell surface, and the application of annexin V labeled with fluorescent dye is presently the most popular tool for its detection. Several methods have been suggested recently that offer important advantages over annexin V assay with the ability to study apoptosis by spectroscopy of cell suspensions, flow cytometry and confocal or two-photon microscopy. The PS exposure marks the integrated changes in the outer leaflet of cell membrane that involve electrostatic potential and hydration, and the attempts are being made to provide direct probing of these changes. This review describes the basic mechanisms underlying the loss of membrane asymmetry during apoptosis and discusses, in comparison with the annexin V-binding assay, the novel fluorescence techniques of detecting apoptosis on cellular membrane level. In more detail we describe the detection method based on smart fluorescent dye F2N12S incorporated into outer leaflet of cell membrane and reporting on apoptotic cell transformation by easily detectable change of the spectral distribution of fluorescent emission. It can be adapted to any assay format. PMID:22797774

  13. 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. PMID:21968568

  14. Leucocyte cellular adhesion molecules.

    PubMed

    Yong, K; Khwaja, A

    1990-12-01

    Leucocytes express adhesion promoting receptors which mediate cell-cell and cell-matrix interactions. These adhesive interactions are crucial to the regulation of haemopoiesis and thymocyte maturation, the direction and control of leucocyte traffic and migration through tissues, and in the development of immune and non-immune inflammatory responses. Several families of adhesion receptors have been identified (Table). The leucocyte integrin family comprises 3 alpha beta heterodimeric membrane glycoproteins which share a common beta subunit, designated CD18. The alpha subunits of each of the 3 members, lymphocyte function associated antigen-1 (LFA-1), macrophage antigen-1 (Mac-1) and p150,95 are designated CD11a, b and c respectively. These adhesion molecules play a critical part in the immune and inflammatory responses of leucocytes. The leucocyte integrin family is, in turn, part of the integrin superfamily, members of which are evolutionally, structurally and functionally related. Another Integrin subfamily found on leucocytes is the VLA group, so-called because the 'very late activation antigens' VLA-1 and VLA-2 were originally found to appear late in T-cell activation. Members of this family function mainly as extracellular matrix adhesion receptors and are found both on haemopoietic and non-haemopoietic cells. They play a part in diverse cellular functions including tissue organisation, lymphocyte recirculation and T-cell immune responses. A third integrin subfamily, the cytoadhesins, are receptors on platelets and endothelial cells which bind extracellular matrix proteins. A second family of adhesion receptors is the immunoglobulin superfamily, members of which include CD2, LFA-3 and ICAM-1, which participate in T-cell adhesive interactions, and the antigen-specific receptors of T and B cells, CD4, CD8 and the MHC Class I and II molecules. A recently recognised family of adhesion receptors is the selectins, characterised by a common lectin domain. Leucocyte

  15. Not Just an Access Issue: Further Analysis of the Digital Divide from a Socioeconomic Perspective

    ERIC Educational Resources Information Center

    Milheim, Karen L.

    2006-01-01

    In recent years, a concern surrounding technology access to historically marginalized populations, referred to as the "Digital Divide" (Divide), has surfaced. This analysis examines the Digital Divide from a socioeconomic standpoint, and discusses the effects of the Divide on students. Also addressed are the varying perspectives towards the…

  16. Arterial tree asymmetry reduces cerebral pulsatility.

    PubMed

    Vrselja, Zvonimir; Brkic, Hrvoje; Curic, Goran

    2015-11-01

    With each heartbeat, pressure wave (PW) propagates from aorta toward periphery. In cerebral circulation, at the level of circle of Willis (CW), four arteries and four PWs converge. Since the interference is an elemental property of the wave, PWs interfere at the level of CW. We hypothesize that the asymmetry of brain-supplying arteries (that join to form CW) creates phase difference between the four PWs that interfere at the level of CW and reduce downstream cerebral pulsatility. To best of our knowledge, the data about the sequence of PWs' arrival into the cerebral circulation is lacking. Evident imperfect bilateral symmetry of the vessels results with different path length of brain-supplying arteries, hence, PWs should arrive into the head at different times. The probabilistic calculation shows that asynchronous arrival is more probable than synchronous. The importance of PWs for the cerebral circulation is highlighted by the observation that barotrauma protection mechanisms are more influenced by the crest of PW (pulse pressure) than by the mean arterial pressure. In addition, an increased arterial pulsatility is associated with several brain pathologies. We created simple computational models of four converging arteries and found that asynchronous arrival of the PWs results with lower maximum pressure, slower rate of pressure amplification and lower downstream pulsatility. In analogy, the asynchronous arrival of the pressure waves into the cerebral circulation should decrease blood flow pulsatility and lower transmission of kinetic energy on arterial wall. We conclude that asynchronous arrival of PWs into the cerebral circulation influences cerebral hemodynamics and represents a physiological necessity. PMID:26277658

  17. Up-down Asymmetries in Speed Perception

    NASA Technical Reports Server (NTRS)

    Thompson, Peter; Stone, Leland S.

    1997-01-01

    We compared speed matches for pairs of stimuli that moved in opposite directions (upward and downward). Stimuli were elliptical patches (2 deg horizontally by 1 deg vertically) of horizontal sinusoidal gratings of spatial. frequency 2 cycles/deg. Two sequential 380 msec reveal presentations were compared. One of each pair of gratings (the standard) moved at 4 Hz (2 deg/sec), the other (the test) moved at a rate determined by a simple up-down staircase. The point of subjectively equal speed was calculated from the average of the last eight reversals. The task was to fixate a central point and to determine which one of the pair appeared to move faster. Eight of 10 observers perceived the upward drifting grating as moving faster than a grating moving downward but otherwise identical. on average (N = 10), when the standard moved downward, it was matched by a test moving upward at 94.7+/-1.7(SE)% of the standard speed, and when the standard moved upward it was matched by a test moving downward at 105.1+/-2.3(SE)% of the standard speed. Extending this paradigm over a range of spatial (1.5 to 13.5 c/d) and temporal (1.5 to 13.5 Hz) frequencies, preliminary results (N = 4) suggest that, under the conditions of our experiment, upward matter is seen as faster than downward for speeds greater than approx.1 deg/sec, but the effect appears to reverse at speeds below approx.1 deg/sec with downward motion perceived as faster. Given that an up-down asymmetry has been observed for the optokinetic response, both perceptual and oculomotor contributions to this phenomenon deserve exploration.

  18. The electrical asymmetry effect in capacitive discharges

    NASA Astrophysics Data System (ADS)

    Czarnetzki, Uwe

    2009-10-01

    One of the major demands in plasma processing has always been the independent control of ion energy and ion flux. Dual-frequency capacitive discharges with one low and one typically an order of magnitude higher frequency are one of the concepts presently applied in industry. However, recent investigations have shown that there is in fact a coupling between the two frequency components that limits independent control by the two RF powers. Here, a novel concept is introduced based on the electrical asymmetry effect (EAE) that provides simple and stable control of ion energy and flux in an almost ideally independent way [1]. Also here two RF frequencies are applied but with the second frequency being exactly the second harmonic of the first and with a fixed but controllable phase. This phase is the control parameter for the ion energy that changes approximately linearly with the phase. Geometrically symmetric discharges can be made effectively asymmetric with one electrode showing a higher sheath potential than the other. Choosing the proper phase allows then to reverse the situation or to make the discharge symmetric. In geometrically asymmetric discharges the wall potential can be raised or lowered. When tuning the phase, the flux stays approximately constant and its absolute value can be set with the RF amplitudes. The concept of the EAE is developed and analyzed by 1) an analytical model, 2) a hydrodynamic and Monte-Carlo (MC) simulation, 3) a self consistent PIC/MC simulation, and 4) an experimental verification in a laboratory experiment. All four approaches show excellent agreement and confirm the above advantages. The technique has found successful application already in an industrial reactor for large area solar cell production (Leybold Optics). Compared to the standard single frequency case at 13.56 MHz the silicon deposition rate was easily more than doubled and the homogeneity improved. [4pt] [1] Brian G. Heil, U. Czarnetzki, R. P. Brinkmann, T

  19. Nanocrystal Bioassembly: Asymmetry, Proximity, and Enzymatic Manipulation

    SciTech Connect

    Claridge, Shelley A.

    2008-05-01

    Research at the interface between biomolecules and inorganic nanocrystals has resulted in a great number of new discoveries. In part this arises from the synergistic duality of the system: biomolecules may act as self-assembly agents for organizing inorganic nanocrystals into functional materials; alternatively, nanocrystals may act as microscopic or spectroscopic labels for elucidating the behavior of complex biomolecular systems. However, success in either of these functions relies heavily uponthe ability to control the conjugation and assembly processes.In the work presented here, we first design a branched DNA scaffold which allows hybridization of DNA-nanocrystal monoconjugates to form discrete assemblies. Importantly, the asymmetry of the branched scaffold allows the formation of asymmetric2assemblies of nanocrystals. In the context of a self-assembled device, this can be considered a step toward the ability to engineer functionally distinct inputs and outputs.Next we develop an anion-exchange high performance liquid chromatography purification method which allows large gold nanocrystals attached to single strands of very short DNA to be purified. When two such complementary conjugates are hybridized, the large nanocrystals are brought into close proximity, allowing their plasmon resonances to couple. Such plasmon-coupled constructs are of interest both as optical interconnects for nanoscale devices and as `plasmon ruler? biomolecular probes.We then present an enzymatic ligation strategy for creating multi-nanoparticle building blocks for self-assembly. In constructing a nanoscale device, such a strategy would allow pre-assembly and purification of components; these constructs can also act as multi-label probes of single-stranded DNA conformational dynamics. Finally we demonstrate a simple proof-of-concept of a nanoparticle analog of the polymerase chain reaction.

  20. DACTAL: divide-and-conquer trees (almost) without alignments

    PubMed Central

    Nelesen, Serita; Liu, Kevin; Wang, Li-San; Linder, C. Randal; Warnow, Tandy

    2012-01-01

    Motivation: While phylogenetic analyses of datasets containing 1000–5000 sequences are challenging for existing methods, the estimation of substantially larger phylogenies poses a problem of much greater complexity and scale. Methods: We present DACTAL, a method for phylogeny estimation that produces trees from unaligned sequence datasets without ever needing to estimate an alignment on the entire dataset. DACTAL combines iteration with a novel divide-and-conquer approach, so that each iteration begins with a tree produced in the prior iteration, decomposes the taxon set into overlapping subsets, estimates trees on each subset, and then combines the smaller trees into a tree on the full taxon set using a new supertree method. We prove that DACTAL is guaranteed to produce the true tree under certain conditions. We compare DACTAL to SATé and maximum likelihood trees on estimated alignments using simulated and real datasets with 1000–27 643 taxa. Results: Our studies show that on average DACTAL yields more accurate trees than the two-phase methods we studied on very large datasets that are difficult to align, and has approximately the same accuracy on the easier datasets. The comparison to SATé shows that both have the same accuracy, but that DACTAL achieves this accuracy in a fraction of the time. Furthermore, DACTAL can analyze larger datasets than SATé, including a dataset with almost 28 000 sequences. Availability: DACTAL source code and results of dataset analyses are available at www.cs.utexas.edu/users/phylo/software/dactal. Contact: tandy@cs.utexas.edu PMID:22689772

  1. Climate Interpretations from the WAIS Divide Water Isotope Record

    NASA Astrophysics Data System (ADS)

    Jones, Tyler R.; White, James W. C.; Cuffey, Kurt M.; Steig, Eric J.; Fudge, Tyler J.; Vaughn, Bruce H.; Morris, Valerie A.; Gkinis, Vasileios; Markle, Bradley R.; Schoenemann, Spruce W.

    2014-05-01

    Ultra-high resolution water isotope measurements (δD, δ18O and deuterium excess) from the WAIS Divide ice core have been analyzed using a continuous flow system (CFA). The CFA measurements (INSTAAR, University of Colorado) have been averaged to 1 cm and compared with 50 cm discrete measurements (Isolab, University of Washington). Downsampling the CFA data, we find significant (>99%) multi-taper coherence between the two measurement techniques (δD and δ18O). The deuterium excess measurements are more difficult to reproduce at high-resolution, but are significantly coherent at longer time scales (100-1000 years). Frequency analysis of the CFA water isotope signal (δD and δ18O) shows 1-year power persists throughout the Holocene and part-way into the Glacial. At 5 ka bp about 50% of the initial water isotope annual amplitude remains, whereas at 9 ka bp about 20% remains. By 15 ka bp yearly power has mostly disappeared. We use the exceptional preservation of the water isotope signal to undertake various analyses including: 1) Interpretation of abrupt climate changes (e.g. AIM events), 2) Frequency analysis of ENSO-type climate oscillations throughout the Holocene and the late-Glacial (e.g. 2-7 year periodicities), and 3) The effects of diffusion on the water isotope signal (e.g. diffusion constrains the temperature, accumulation during firn densification, and dynamic thinning history, which could be used to invert for these parameters). These analyses are ongoing as we continue to develop our methodologies and CFA system processing code.

  2. Breast Volume Asymmetry Value, Ratio, and Cancer Risk

    PubMed Central

    Kayar, Ragıp; Çilengiroğlu, Özgül V.

    2015-01-01

    AIM The aim of this study was to investigate the criteria for determining the cancer risk of the breast asymmetry by comparing breast volume asymmetry levels between healthy women and women with cancer. MATERIALS AND METHODS Two hundred and one women with breast cancer (group 1) were compared with 446 healthy women (group 2) who had no pathologic findings in breast sonography and mammograpy repeated with one-year interval. Data were evaluated retrospectively. Each breast volume was measured twice by Grossman-Roudner Discs. The mean value has been recorded. The amounts of volume difference between two breasts (asymmetry value) and the rates of the volume difference to the breast volume of the smaller side (asymmetry ratio) were compared in both groups. RESULTS There was a statistically significant difference between two groups with regard to average age and body mass index (P < 0.01). This significance was decreased but not disappeared, when the comparison was made within the 40–69 age group (P > 0.01). The rate of cases with asymmetry value over 50 mL was significantly higher in the cancer group (P = 0.029). Unfortunately, it disappeared in the 40–69 age group (P = 0.201). The breast volume asymmetry ratio over 20% was significantly higher in the cancer group both in all ages and in the 40–69 age group (P < 0.01). Odds ratio was 2.18 in the entire (all) series and 2.01 in the 40–69 age group. Moreover, there was no significant difference with regard to the rate of tumor location between the smaller or larger side of breast. CONCLUSION Our data show that there is a positive correlation between breast asymmetry ratio over 20% and breast cancer risk. These results need to be confirmed by prospective randomized controlled trials. PMID:26691819

  3. A complex evaluation of the asymmetry of dermatoglyphs.

    PubMed

    Buchwald, W; Grubska, B

    2012-10-01

    Altogether 20 traits of the fingers, 22 traits of the palm and 8 traits of the sole were taken into consideration, on both sides of the bodies of 1652 males and 1628 females. Numbers of asymmetrical variants of the traits within the whole complex of 25 pairs of traits were determined individually. In the case of descriptive traits, asymmetry was deemed to be the occurrence on either side of the body of non-identical variants of the traits, and for quantitative traits, the absolute difference of at least two ridges was accepted. These differences were marked with the value 1 (additionally 0.5 on the fingers when the difference concerned only the direction of the pattern). The sum of these values constituted the total number of asymmetric traits, which was expressed by the index: IA=number of asymmetric traits×100/25. For individual traits, the frequency of asymmetric variants was determined, and here the measure of asymmetry was expressed as the relations of their sum to the total numbers. In both sexes, the lowest level of asymmetry concerns patterns of the II inter-digital area, the thenar, the IV, III and I areas of the sole, and fingers 5 and 3, while the highest level concerns patterns of finger 2, asymmetry of C-line and A-line exits, the ridge count on the fingers and in the inter-digital areas of the palm. The greatest dimorphism is demonstrated by the asymmetry of the patterns of the II inter-digital area of the palm, finger 4, the IV area of the sole, the thenar, finger 1, line B and the ridge count on finger 2. As a consequence, the mean of the asymmetry index (IA) in males (46.24) is higher than in females (44.43). The proposed index of dermatoglyphic asymmetry (IA) may be used for comparative purposes in population, clinical, auxological and genetic research. PMID:22981245

  4. Asymmetrical Inheritance of Plasmids Depends on Dynamic Cellular Geometry and Volume Exclusion Effects

    PubMed Central

    Marquez-Lago, Tatiana T.

    2015-01-01

    The asymmetrical inheritance of plasmid DNA, as well as other cellular components, has been shown to be involved in replicative aging. In Saccharomyces cerevisiae, there is an ongoing debate regarding the mechanisms underlying this important asymmetry. Currently proposed models suggest it is established via diffusion, but differ on whether a diffusion barrier is necessary or not. However, no study so far incorporated key aspects to segregation, such as dynamic morphology changes throughout anaphase or plasmids size. Here, we determine the distinct effects and contributions of individual cellular variability, plasmid volume and moving boundaries in the asymmetric segregation of plasmids. We do this by measuring cellular nuclear geometries and plasmid diffusion rates with confocal microscopy, subsequently incorporating this data into a growing domain stochastic spatial simulator. Our modelling and simulations confirms that plasmid asymmetrical inheritance does not require an active barrier to diffusion, and provides a full analysis on plasmid size effects. PMID:26468952

  5. Asymmetrical Inheritance of Plasmids Depends on Dynamic Cellular Geometry and Volume Exclusion Effects.

    PubMed

    Denton, Jai A; Ghosh, Atiyo; Marquez-Lago, Tatiana T

    2015-01-01

    The asymmetrical inheritance of plasmid DNA, as well as other cellular components, has been shown to be involved in replicative aging. In Saccharomyces cerevisiae, there is an ongoing debate regarding the mechanisms underlying this important asymmetry. Currently proposed models suggest it is established via diffusion, but differ on whether a diffusion barrier is necessary or not. However, no study so far incorporated key aspects to segregation, such as dynamic morphology changes throughout anaphase or plasmids size. Here, we determine the distinct effects and contributions of individual cellular variability, plasmid volume and moving boundaries in the asymmetric segregation of plasmids. We do this by measuring cellular nuclear geometries and plasmid diffusion rates with confocal microscopy, subsequently incorporating this data into a growing domain stochastic spatial simulator. Our modelling and simulations confirms that plasmid asymmetrical inheritance does not require an active barrier to diffusion, and provides a full analysis on plasmid size effects. PMID:26468952

  6. Asymmetry of the winter extra-tropical teleconnections in the Northern Hemisphere associated with two types of ENSO

    NASA Astrophysics Data System (ADS)

    Feng, Juan; Chen, Wen; Li, Yanjie

    2016-05-01

    Asymmetric atmospheric responses to ENSO are revisited after dividing it into two types: eastern-Pacific (EP) and central-Pacific (CP) ENSO. The EP ENSO triggers two obvious asymmetric atmospheric teleconnections: One is the Pacific-North American-like teleconnection. Its asymmetry is characterized by weaker amplitudes during the EP La Niña than EP El Niño, which is caused by a much weaker EP La Niña tropical forcing and the resultant weaker extra-tropical vorticity forcing. The other is the Atlantic-Eurasian teleconnection with negative height anomalies in the subtropical Atlantic and Eurasia and positive anomalies in the high-latitude Atlantic and northeast Asia, which appears during the EP La Niña but not during the EP El Niño. The background state plays a vital role in this asymmetry. The EP La Niña-type basic state is more conducive to propagation of the wave rays into the Atlantic-Eurasian region compared to EP El Niño situation. In contrast, the CP ENSO yields an Arctic Oscillation-like teleconnection, presenting an appreciable asymmetry in the subtropical amplitudes that are stronger during the CP El Niño than during the CP La Niña. In this case, the distinct effects of the different background state on the equatorward wave rays are responsible for this asymmetry. Under the CP El Niño-type background state, the equatorward wave rays tend to be reflected at the latitudes where the zonal wind equals zero (U = 0), and then successfully captured by the subtropical westerly jet. However, under the CP La Niña-type background state, the equatorward wave rays disappear at U = 0 latitudes.

  7. Bridging the Divide: Translating Landsat Research Into Usable Science

    NASA Astrophysics Data System (ADS)

    Rocchio, L. E.; Davis, A. L.

    2006-12-01

    Science has long served humankind. Breakthroughs in medicine have increased longevity and advances in technology have made modern-day conveniences possible. Yet, social benefits begotten by the environmental sciences, although critical for the survival of humanity, have not always been as widely recognized or used. To benefit today's rapidly growing population, the divides between environmental research, applied environmental science, and use of this information by decision makers must be bridged. Lessons about the translation from research to usable science can be learned from the four decades of Landsat history, and these lessons can serve as useful models for bridging the gaps between new technology, scientific research, and the use of that research and technology in real-world problem solving. In 1965, William Pecora, then-director of the U.S. Geological Survey, proposed the idea of a remote sensing satellite program to gather facts about natural resources of Earth. For the next seven years, an intense campaign showing the depth and diversity of satellite imagery applications was waged. This led to the 1972 launch of the first civilian land-observing satellite, Landsat 1. By 1975, successful application research based on Landsat 1 imagery prompted then-NASA Administrator Dr. James Fletcher to proclaim that if one space age development would save the world, it would be Landsat and its successor satellites. Thirty-four years of continual Landsat imaging and related-research has lead to the implementation of many socially beneficial applications, such as improved water management techniques, crop insurance fraud reduction, illicit crop inventories, natural disaster relief planning, continent-scale carbon estimates, and extensive cartographic advances. Despite these successes, the challenge of translating Landsat research into realized social benefits remains. Even in this geospatially-savvy era, the utility of Landsat largely escapes policymakers. Here, in an

  8. Bridging the divide between genomic science and indigenous peoples.

    PubMed

    Jacobs, Bette; Roffenbender, Jason; Collmann, Jeff; Cherry, Kate; Bitsói, LeManuel Lee; Bassett, Kim; Evans, Charles H

    2010-01-01

    definition of "rigorous scientific research," one that includes both community development and scientific progress as legitimate objectives of genomic research. Innovative translational research is needed to develop practical, mutually acceptable methods for crossing the divide between genomic researchers and indigenous communities. This may mean the difference between success and failure in genomic science, and in improving health for all peoples. PMID:20880250

  9. The transatlantic divide over brain death determination and the debate.

    PubMed

    Wijdicks, Eelco F M

    2012-04-01

    In 1976, the Royal College of Physicians published neurological criteria of death. The memorandum stated that-after preconditions and exclusion criteria were met-the absence of brainstem function, including apnoea testing, would suffice. In the USA, many experts felt that brain death could be only determined by demonstrating death of the entire brain. In the history of further refinement of UK and USA brain death criteria, one particular period stands out that would bring about an apparent transatlantic divide. On 13 October 1980, the British Broadcasting Corporation aired a programme entitled 'Transplants: Are the Donors Really Dead?' Several United States experts not only disagreed with the United Kingdom criteria, but claimed that patients diagnosed with brain death using United Kingdom criteria could recover. The fallout of this television programme was substantial, as indicated by a media frenzy and a 6-month period of heated correspondence within The Lancet and The British Medical Journal. Members of the Parliament questioned the potential long-term effect on the public's trust in organ transplantation. Given the concerns raised, the British Broadcasting Corporation commissioned a second programme, which was broadcast on 19 February 1981 entitled 'A Question of Life or Death: The Brain Death Debate.' Two panels debated the issues on the accuracy of the electroencephalogram and its place, the absolute need for assessing preconditions before an examination, the problems with recognition of toxins and the feasibility of doing a new prospective study in the United Kingdom, which would follow patients' examination assessed with United Kingdom criteria until cardiac standstill. The positions of the United States and United Kingdom remained diametrically opposed to each other. This article revisits this landmark moment and places it in a wider historical context. In the USA, the focus was not on the brainstem, and the definition of brain death became rapidly infused

  10. High-strength cellular ceramic composites with 3D microarchitecture

    PubMed Central

    Bauer, Jens; Hengsbach, Stefan; Tesari, Iwiza; Schwaiger, Ruth; Kraft, Oliver

    2014-01-01

    To enhance the strength-to-weight ratio of a material, one may try to either improve the strength or lower the density, or both. The lightest solid materials have a density in the range of 1,000 kg/m3; only cellular materials, such as technical foams, can reach considerably lower values. However, compared with corresponding bulk materials, their specific strength generally is significantly lower. Cellular topologies may be divided into bending- and stretching-dominated ones. Technical foams are structured randomly and behave in a bending-dominated way, which is less weight efficient, with respect to strength, than stretching-dominated behavior, such as in regular braced frameworks. Cancellous bone and other natural cellular solids have an optimized architecture. Their basic material is structured hierarchically and consists of nanometer-size elements, providing a benefit from size effects in the material strength. Designing cellular materials with a specific microarchitecture would allow one to exploit the structural advantages of stretching-dominated constructions as well as size-dependent strengthening effects. In this paper, we demonstrate that such materials may be fabricated. Applying 3D laser lithography, we produced and characterized micro-truss and -shell structures made from alumina–polymer composite. Size-dependent strengthening of alumina shells has been observed, particularly when applied with a characteristic thickness below 100 nm. The presented artificial cellular materials reach compressive strengths up to 280 MPa with densities well below 1,000 kg/m3. PMID:24550268

  11. Cellular compartmentalization of secondary metabolism

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fungal secondary metabolism is often considered apart from the essential housekeeping functions of the cell. However, there are clear links between fundamental cellular metabolism and the biochemical pathways leading to secondary metabolite synthesis. Besides utilizing key biochemical precursors sh...

  12. Cellular therapy for haematological malignancies.

    PubMed

    Roddie, P H; Turner, M L

    2002-11-01

    The aim of this review was to summarize the recent progress made in the field of cellular therapeutics in haematological malignancy. The review also examined the role that the National Transfusion Services might play in the manufacture of new cellular therapeutic agents, given both their expertise in the safe provision of blood products and their possession of accredited cell manipulation facilities. Cellular therapy is entering an era in which novel cellular products will find increasing clinical use, particularly in the areas of haematopoietic stem cell transplantation and immunotherapy. The production of novel cell-based therapies, both in Europe and North America, is now under strict regulatory control and therefore collaboration with the National Transfusion Services in the manufacture of these agents may well be beneficial if the production standards demanded by the regulatory authorities are to be fulfilled. PMID:12437515

  13. Prefrontal Asymmetry and Parent-Rated Temperament in Infants

    PubMed Central

    LoBue, Vanessa; Coan, James A.; Thrasher, Cat; DeLoache, Judy S.

    2011-01-01

    Indicators of temperament appear early in infancy and remain relatively stable over time. Despite a great deal of interest in biological indices of temperament, most studies of infant temperament rely on parental reports or behavioral tasks. Thus, the extent to which commonly used temperament measures relate to potential biological indicators of infant temperament is still relatively unknown. The current experiment examines the relationship between a common parental report measure of temperament – the Infant Behavior Questionnaire – Revised (IBQ-R) – and measures of frontal EEG asymmetry in infants. We examined associations between the subscales of the IBQ-R and frontal EEG asymmetry scores recorded during a combined series of neutral attentional and putatively emotional recording conditions in infants between 7 and 9 months of age. We predicted that approach-related subscales of the IBQ-R (e.g., Approach, Soothability) would be related to greater left prefrontal asymmetry, while withdrawal-related subscales (e.g., Distress to Limitations, Fear, Falling Reactivity, Perceptual Sensitivity) would be related to greater right prefrontal asymmetry. In the mid- and lateral-frontal regions, Approach, Distress to Limitations, Fear, Soothability, and Perceptual Sensitivity were generally associated with greater left frontal activation (rs≥.23, ps<0.05), while only Falling Reactivity was associated with greater right frontal activation (rs≤−.44, ps<0.05). Results suggest that variability in frontal EEG asymmetry is robustly associated with parental report measures of temperament in infancy. PMID:21829482

  14. Abnormality of EEG alpha asymmetry in female adolescent suicide attempters.

    PubMed

    Graae, F; Tenke, C; Bruder, G; Rotheram, M J; Piacentini, J; Castro-Blanco, D; Leite, P; Towey, J

    1996-10-15

    Abnormal electroencephalographic (EEG) activity has been associated with various psychiatric disorders and behaviors, including depression, suicide, and aggression. We examined quantitative resting EEG in Hispanic female adolescent suicide attempters and matched normal controls. Computerized EEG measures were recorded at 11 scalp sites during eyes open and eyes closed periods from 16 suicide attempters and 22 normal controls. Suicide attempters differed from normal controls in alpha asymmetry. Normal adolescents had greater alpha (less activation) over right than left hemisphere, whereas suicidal adolescents had a nonsignificant asymmetry in the opposite direction. Nondepressed attempters were distinguished from depressed attempters in that they accounted for the preponderance of abnormal asymmetry, particularly in posterior regions. Alpha asymmetry over posterior regions was related to ratings of suicidal intent, but not depression severity. The alpha asymmetry in suicidal adolescents resembled that seen for depressed adults in its abnormal direction, but not in its regional distribution. Findings for suicidal adolescents are discussed in terms of a hypothesis of reduced left posterior activation, which is not related to depression but to suicidal or aggressive behavior. PMID:8894062

  15. EEG Asymmetry and ERN: Behavioral Outcomes in Preschoolers

    PubMed Central

    Begnoche, J. Patrick; Brooker, Rebecca J.; Vess, Matthew

    2016-01-01

    Research has documented reciprocal influences between approach-related and inhibition-related neural activity in adults. However, associations between neural systems of approach and inhibition have not been tested in children. It is thus unclear whether these links are present early in life and whether associations between neural systems of approach and inhibition have long-term behavioral consequences. To address these gaps in the literature, we used electroencephalography (EEG) to examine associations between approach-related neural activity (i.e., hemispheric asymmetry) and inhibition-related neural activity (i.e., error-related negativity [ERN]) in preschool-aged children. Furthermore, we explored whether interactions between asymmetry and ERN predicted social inhibition, a precursor to anxiety problems, or symptoms of Attention Deficit Hyperactivity Disorder (ADHD) six months later. Similar to research on adults, greater left asymmetry (i.e., greater approach-related neural activity) was correlated with reduced ERN amplitude (i.e., weaker inhibition-related neural activity). The interactive effect of asymmetry and ERN amplitude did not predict ADHD symptoms, but did predict social inhibition. When ERN was greater, less left asymmetry was associated with higher levels of social inhibition. Results were most prominent at parietal EEG sites. Implications for understanding the development of the overlap in neural systems of approach and inhibition are discussed. PMID:27223612

  16. Prediction of Gap Asymmetry in Differential Micro Accelerometers

    PubMed Central

    Zhou, Wu; Li, Baili; Peng, Bei; Su, Wei; He, Xiaoping

    2012-01-01

    Gap asymmetry in differential capacitors is the primary source of the zero bias output of force-balanced micro accelerometers. It is also used to evaluate the applicability of differential structures in MEMS manufacturing. Therefore, determining the asymmetry level has considerable significance for the design of MEMS devices. This paper proposes an experimental-theoretical method for predicting gap asymmetry in differential sensing capacitors of micro accelerometers. The method involves three processes: first, bi-directional measurement, which can sharply reduce the influence of the feedback circuit on bias output, is proposed. Experiments are then carried out on a centrifuge to obtain the input and output data of an accelerometer. Second, the analytical input-output relationship of the accelerometer with gap asymmetry and circuit error is theoretically derived. Finally, the prediction methodology combines the measurement results and analytical derivation to identify the asymmetric error of 30 accelerometers fabricated by DRIE. Results indicate that the level of asymmetry induced by fabrication uncertainty is about ±5 × 10−2, and that the absolute error is about ±0.2 μm under a 4 μm gap. PMID:22969325

  17. Quasi-Classical Origins of Single Transverse Spin Asymmetries

    NASA Astrophysics Data System (ADS)

    Sievert, Matthew; Kovchegov, Yuri

    2013-10-01

    We consider semi-inclusive deep inelastic scattering and the Drell-Yan process on a transversely-polarized proton at high energies. We model the small- x wave function of the proton using the McLerran-Venugopalan (MV) model, which has been reasonably successful in describing high-energy proton data. The MV model, originally formulated for a heavy ion with a large number ~ A of independent color charges, is a quasi-classical description that should apply to any dense system of color charges, including a proton at very high energies. Here we incorporate spin dependence into the MV framework and analyze several microscopic scattering channels that lead to the generation of a single transverse spin asymmetry. In particular, we study asymmetries mediated by intrinsic orbital angular momentum, asymmetries produced locally by rescattering on the same constituent, and asymmetries that couple to the odderon. This analysis yields a simple, intuitive, quasi-classical picture in which one can understand understand the famous sign-reversal of the Sivers asymmetry between semi-inclusive deep inelastic scattering and the Drell-Yan process. Sponsored in part by DOE Grant No. DE-SC0004286.

  18. Forward-backward asymmetry in top quark-antiquark production

    SciTech Connect

    Abazov, Victor Mukhamedovich

    2011-12-12

    We present a measurement of forward-backward asymmetry in top quark-antiquark production in proton-antiproton collisions in the final state containing a lepton and at least four jets. Using a dataset corresponding to an integrated luminosity of 5.4 fb-1, collected by the D0 experiment at the Fermilab Tevatron Collider, we measure the t{bar t} forward-backward asymmetry to be (9.2 ± 3.7)% at the reconstruction level. When corrected for detector acceptance and resolution, the asymmetry is found to be (19.6 ± 6.5)%. We also measure a corrected asymmetry based on the lepton from a top quark decay, found to be (15.2 ± 4.0)%. The results are compared to predictions based on the next-to-leading-order QCD generator mc@nlo. The sensitivity of the measured and predicted asymmetries to the modeling of gluon radiation is discussed.

  19. Evaluation of mandibular contour in patients with significant facial asymmetry.

    PubMed

    Fang, J-J; Tu, Y-H; Wong, T-Y; Liu, J-K; Zhang, Y-X; Leong, I-F; Chen, K-C

    2016-07-01

    Most previous studies on facial asymmetry have not specifically differentiated mandible deviation from structural asymmetry of the mandible. The purpose of this study was to assess the symmetry of the mandible by examining its contour in a cohort of patients with significant facial asymmetry. Eleven cases of facial asymmetry with chin deviation ≥10mm were enrolled. A voxel-paired median plane (optimal symmetry plane, OSP) and two landmark-based median planes were generated. The OSP was created by computing the best pairing of the bony voxels on the two sides. One side of the mandibular contour was mirrored onto the other side using the test plane. The contour differences were measured by distance and by area ratio. They were examined both in frontal and frontal downward inclined view. The contour symmetry of the mandible was that revealed by the plane that presented the best symmetry. The results showed that the OSP worked best in bisecting the contour into two symmetrical halves. Contour analysis showed relatively small discrepancies between the two sides. In conclusion, the mandibles retained an acceptable contour symmetry despite the presence of significant mandibular deviations. It is suggested that proper mandibular alignment be the primary objective in the correction of facial asymmetry. PMID:26976218

  20. Frobenius-norm-based measures of quantum coherence and asymmetry.

    PubMed

    Yao, Yao; Dong, G H; Xiao, Xing; Sun, C P

    2016-01-01

    We formulate the Frobenius-norm-based measures for quantum coherence and asymmetry respectively. In contrast to the resource theory of coherence and asymmetry, we construct a natural measure of quantum coherence inspired from optical coherence theory while the group theoretical approach is employed to quantify the asymmetry of quantum states. Besides their simple structures and explicit physical meanings, we observe that these quantities are intimately related to the purity (or linear entropy) of the corresponding quantum states. Remarkably, we demonstrate that the proposed coherence quantifier is not only a measure of mixedness, but also an intrinsic (basis-independent) quantification of quantum coherence contained in quantum states, which can also be viewed as a normalized version of Brukner-Zeilinger invariant information. In our context, the asymmetry of N-qubit quantum systems is considered under local independent and collective transformations. In- triguingly, it is illustrated that the collective effect has a significant impact on the asymmetry measure, and quantum correlation between subsystems plays a non-negligible role in this circumstance. PMID:27558009

  1. Frobenius-norm-based measures of quantum coherence and asymmetry

    PubMed Central

    Yao, Yao; Dong, G. H.; Xiao, Xing; Sun, C. P.

    2016-01-01

    We formulate the Frobenius-norm-based measures for quantum coherence and asymmetry respectively. In contrast to the resource theory of coherence and asymmetry, we construct a natural measure of quantum coherence inspired from optical coherence theory while the group theoretical approach is employed to quantify the asymmetry of quantum states. Besides their simple structures and explicit physical meanings, we observe that these quantities are intimately related to the purity (or linear entropy) of the corresponding quantum states. Remarkably, we demonstrate that the proposed coherence quantifier is not only a measure of mixedness, but also an intrinsic (basis-independent) quantification of quantum coherence contained in quantum states, which can also be viewed as a normalized version of Brukner-Zeilinger invariant information. In our context, the asymmetry of N-qubit quantum systems is considered under local independent and collective transformations. In- triguingly, it is illustrated that the collective effect has a significant impact on the asymmetry measure, and quantum correlation between subsystems plays a non-negligible role in this circumstance. PMID:27558009

  2. Measurement of Z{sup 0} lepton coupling asymmetries

    SciTech Connect

    Smy, M.B.

    1997-07-01

    Polarized Z{sup 0}`s from e{sup +}e{sup {minus}} collisions at the SLAC Linear Collider (SLC) have been used to determine the asymmetry parameters A{sub e}, A{sub {mu}} and A{sub {tau}} from the leptonic decay channels. This is the first direct measurement of A{sub {mu}}. The data have been gathered by the SLC Large Detector (SLD) with the electron polarization averaging 63% during the 1993 data taking period and 77% in 1994-95. A maximum likelihood procedure as well as cross section asymmetries was used to measure the asymmetry parameters from the differential cross sections for equal luminosities of left- and right-handed electron beams. The polarization-dependent muon-pair distributions give A{sub {mu}} = 0.102 {+-}0.034 and the tau-pairs give A{sub {tau}} = 0.195 {+-}0.034. The initial state electronic couplings in all three leptonic channels as well as the final state angular distribution in the e{sup +}e{sup {minus}} final state measure A{sub e} to be A{sub e} = 0.152{+-}0.012. Assuming lepton universality and defining a global leptonic asymmetry parameter A{sub e-{mu}-{tau}} = 0.151{+-}0.011. This global leptonic asymmetry value translates directly into sin{sup 2}{theta}{sub W}{sup eff}=0.2310{+-}0.0014 at the Z{sup 0} pole.

  3. Atypical EEG Beta Asymmetry in Adults with ADHD1

    PubMed Central

    Hale, T. Sigi; Smalley, Susan L.; Walshaw, Patricia D.; Hanada, Grant; Macion, James; McCracken, James T.; McGough, James J.; Loo, Sandra K.

    2010-01-01

    Background Abnormal brain laterality (ABL) is well established in ADHD. However, its clinical specificity and association to cognitive and clinical symptoms is not yet understood. Previous studies indicate increased right hemisphere (RH) contribution in both ADHD and reading impaired samples. The current study investigates whether this ABL characteristic occurs in adults with ADHD absent comorbid language impairment. Methods EEG beta asymmetry was compared in 35 adult ADHD subjects and 104 controls during rest and active cognition. Group differences in beta asymmetry were then further evaluated for association to linguistic and attentional abilities, as well as association to beta asymmetry measures across different brain regions. Results Adults with ADHD showed pronounced rightward beta asymmetry (p = .00001) in inferior parietal regions (P8-P7) during a continuous performance task (CPT) that could not be attributed to linguistic ability. Among ADHD subjects only, greater rightward beta asymmetry at this measure was correlated with better CPT performance. Furthermore, this measure showed a lack of normal association (i.e., observed in controls) to left-biased processing in temporal-parietal (TP8-TP7) brain regions important for higher order language functions. Conclusion Adult ADHD involves abnormally increased right-biased contribution to CPT processing that could not be attributed to poor language ability. This appears to also involve abnormal recruitment of LH linguistic processing regions and represents an alternative, albeit less effective, CPT processing strategy. These findings suggest different pathophysiologic mechanisms likely underlie RH biased processing in ADHD and reading impaired samples. PMID:20705076

  4. Ambiguities and Asymmetries in Consent and Refusal: Reply to Manson.

    PubMed

    Lawlor, Rob

    2016-06-01

    John Harris claims that is it 'palpable nonsense' to suggest that 'a child (or anyone) might competently consent to a treatment but not be competent to refuse it.' In 'Transitional Paternalism: How Shared Normative Powers Give Rise to the Asymmetry of Adolescent Consent and Refusal' Neil Manson aims to explain away the apparent oddness of this asymmetry of consent and refusal, by appealing to the idea of shared normative powers, presenting joint bank accounts as an example. In this article, I will argue that Manson's account fails to explain away the oddness. Rather, I will argue that there are ambiguities to which Manson has not paid sufficient attention. In fact, as odd as it may sound, I argue that Manson actually agrees with Harris (at least in relation to the asymmetry of competence). He fails to recognize that he agrees with Harris because he is not careful enough to distinguish between different asymmetries, which I have labelled the asymmetries of choice, permissibility and competence. PMID:26424104

  5. Patterns and development of floral asymmetry in Senna (Leguminosae, Cassiinae).

    PubMed

    Marazzi, Brigitte; Endress, Peter K

    2008-01-01

    The buzz-pollinated genus Senna (Leguminosae) is outstanding for including species with monosymmetric flowers and species with diverse asymmetric, enantiomorphic (enantiostylous) flowers. To recognize patterns of homology, we dissected the floral symmetry character complex and explored corolla morphology in 60 Senna species and studied floral development of four enantiomorphic species. The asymmetry morph of a flower is correlated with the direction of spiral calyx aestivation. We recognized five patterns of floral asymmetry, resulting from different combinations of six structural elements: deflection of the carpel, deflection of the median abaxial stamen, deflection or modification in size of one lateral abaxial stamen, and modification in shape and size of one or both lower petals. Prominent corolla asymmetry begins in the earl-stage bud (unequal development of lower petals). Androecium asymmetry begins either in the midstage bud (unequal development of thecae in median abaxial stamen; twisting of androecium) or at anthesis (stamen deflection). Gynoecium asymmetry begins in early bud (primordium off the median plane, ventral slit laterally oriented) or midstage to late bud (carpel deflection). In enantiostylous flowers, pronouncedly concave and robust petals of both monosymmetric and asymmetric corollas likely function to ricochet and direct pollen flow during buzz pollination. Occurrence of particular combinations of structural elements of floral symmetry in the subclades is shown. PMID:21632312

  6. Solar wind driving of asymmetries in the magnetosheath - magnetosphere system

    NASA Astrophysics Data System (ADS)

    Dimmock, Andrew; Pulkkinen, Tuija; Osmane, Adnane; Nykyri, Katariina

    2015-04-01

    Over the decades of in-situ measurements of the terrestrial magnetosphere it has been suggested and experimentally shown that various parameter dawn-dusk asymmetries arise. What is also apparent is that such asymmetries are delicately coupled to the properties of the solar wind. The IMF configuration has a considerable impact since its orientation dictates the shock geometry, thus driving different dawn-dusk plasma properties downstream. Magnetosheath asymmetries are notably important since the magnetosheath effectively modifies and reconfigures plasma before it enters the inner magnetosphere and therefore may play a role in driving asymmetries in the inner magnetosphere. We apply our existing statistical mapping tool which uses over 7 years of THEMIS and OMNI data to create statistical maps of plasma properties in the global magnetospheric system. We look at asymmetries of both steady state properties (e.g. B, V, n), and also transient/kinetic features such as mirror mode activity. We focus specifically on 1. solar wind dependence and 2. the co-dependence between the magnetosheath and magnetospheric regions.

  7. Forward-backward asymmetry in top quark-antiquark production

    DOE PAGESBeta

    Abazov, Victor Mukhamedovich

    2011-12-12

    We present a measurement of forward-backward asymmetry in top quark-antiquark production in proton-antiproton collisions in the final state containing a lepton and at least four jets. Using a dataset corresponding to an integrated luminosity of 5.4 fb-1, collected by the D0 experiment at the Fermilab Tevatron Collider, we measure the t{bar t} forward-backward asymmetry to be (9.2 ± 3.7)% at the reconstruction level. When corrected for detector acceptance and resolution, the asymmetry is found to be (19.6 ± 6.5)%. We also measure a corrected asymmetry based on the lepton from a top quark decay, found to be (15.2 ± 4.0)%.more » The results are compared to predictions based on the next-to-leading-order QCD generator mc@nlo. The sensitivity of the measured and predicted asymmetries to the modeling of gluon radiation is discussed.« less

  8. EEG Asymmetry and ERN: Behavioral Outcomes in Preschoolers.

    PubMed

    Begnoche, J Patrick; Brooker, Rebecca J; Vess, Matthew

    2016-01-01

    Research has documented reciprocal influences between approach-related and inhibition-related neural activity in adults. However, associations between neural systems of approach and inhibition have not been tested in children. It is thus unclear whether these links are present early in life and whether associations between neural systems of approach and inhibition have long-term behavioral consequences. To address these gaps in the literature, we used electroencephalography (EEG) to examine associations between approach-related neural activity (i.e., hemispheric asymmetry) and inhibition-related neural activity (i.e., error-related negativity [ERN]) in preschool-aged children. Furthermore, we explored whether interactions between asymmetry and ERN predicted social inhibition, a precursor to anxiety problems, or symptoms of Attention Deficit Hyperactivity Disorder (ADHD) six months later. Similar to research on adults, greater left asymmetry (i.e., greater approach-related neural activity) was correlated with reduced ERN amplitude (i.e., weaker inhibition-related neural activity). The interactive effect of asymmetry and ERN amplitude did not predict ADHD symptoms, but did predict social inhibition. When ERN was greater, less left asymmetry was associated with higher levels of social inhibition. Results were most prominent at parietal EEG sites. Implications for understanding the development of the overlap in neural systems of approach and inhibition are discussed. PMID:27223612

  9. Mathematical Modeling of Cellular Metabolism.

    PubMed

    Berndt, Nikolaus; Holzhütter, Hermann-Georg

    2016-01-01

    Cellular metabolism basically consists of the conversion of chemical compounds taken up from the extracellular environment into energy (conserved in energy-rich bonds of organic phosphates) and a wide array of organic molecules serving as catalysts (enzymes), information carriers (nucleic acids), and building blocks for cellular structures such as membranes or ribosomes. Metabolic modeling aims at the construction of mathematical representations of the cellular metabolism that can be used to calculate the concentration of cellular molecules and the rates of their mutual chemical interconversion in response to varying external conditions as, for example, hormonal stimuli or supply of essential nutrients. Based on such calculations, it is possible to quantify complex cellular functions as cellular growth, detoxification of drugs and xenobiotic compounds or synthesis of exported molecules. Depending on the specific questions to metabolism addressed, the methodological expertise of the researcher, and available experimental information, different conceptual frameworks have been established, allowing the usage of computational methods to condense experimental information from various layers of organization into (self-) consistent models. Here, we briefly outline the main conceptual frameworks that are currently exploited in metabolism research. PMID:27557541

  10. Cone-beam computed tomography based evaluation of rotational patterns of dentofacial structures in skeletal Class III deformity with mandibular asymmetry

    PubMed Central

    Ryu, Hyeong-Seok; An, Ki-Yong

    2015-01-01

    Objective The purpose of this study was to assess rotational patterns of dentofacial structures according to different vertical skeletal patterns by cone-beam computed tomography (CBCT) and analyze their influence on menton deviation in skeletal Class III deformity with mandibular asymmetry. Methods The control group consisted of 30 young adults (15 men, 15 women) without any severe skeletal deformity. The asymmetry group included 55 adults (28 men, 27 women) with skeletal Class III deformity and at least 3-mm menton deviation from the midsagittal plane; it was divided into the hyperdivergent and hypodivergent subgroups using a mandibular plane angle cutoff of 35°. Fourteen rotational variables of the dental arches and mandible were measured and compared among the groups. Correlations between menton deviation and the other variables were evaluated. Results The asymmetry group showed significantly larger measurements of roll and yaw in the mandible than the control group. The hypodivergent subgroup showed significant differences in maxillary posterior measurements of yaw (p < 0.01) and maxillary anterior shift (p < 0.05) compared with the hyperdivergent subgroup. All the mandibular measurements had significant correlations with menton deviation (p < 0.01). Most measurements of roll were positively correlated with one another (p < 0.01). Measurements of yaw and roll in the posterior regions were also positively correlated (p < 0.05). Conclusions Menton deviation in skeletal Class III deformity with mandibular asymmetry is influenced by rotation of mandibular posterior dentofacial structures. The rotational patterns vary slightly according to the vertical skeletal pattern. PMID:26258061

  11. Dividers for reduction of aerodynamic drag of vehicles with open cavities

    NASA Technical Reports Server (NTRS)

    Storms, Bruce L. (Inventor)

    2007-01-01

    A drag-reduction concept for vehicles with open cavities includes dividing a cavity into smaller adjacent cavities through installation of one or more vertical dividers. The dividers may extend the full depth of the cavity or only partial depth. In either application, the top of the dividers are typically flush with the top of the bed or cargo bay of the vehicle. The dividers may be of any material, but are strong enough for both wind loads and forces encountered during cargo loading/unloading. For partial depth dividers, a structural angle may be desired to increase strength.

  12. Work on the Interplay Among h+, h‑ and Hadron Pair Transverse Spin Asymmetries in SIDIS

    NASA Astrophysics Data System (ADS)

    Bradamante, Franco

    2016-02-01

    In the fragmentation of a transversely polarized quark a left-right asymmetry, the Collins asymmetry, is expected for each hadron produced in the process μN → μ‧h+h‑X. Similarly, an asymmetry is also expected for the hadron pair, the dihadron asymmetry. Both asymmetries have been measured to be different from zero on transversely polarised proton targets and have allowed for first extractions of the transversity distributions. From the high statistics COMPASS data we have further investigated these asymmetries getting strong indications that the two mechanisms are driven by a common physical process.

  13. Transverse target spin asymmetries in exclusive ρ0 muoproduction

    NASA Astrophysics Data System (ADS)

    Adolph, C.; Akhunzyanov, R.; Alekseev, M. G.; Alexakhin, V. Yu.; Alexandrov, Yu.; Alexeev, G. D.; Amoroso, A.; Andrieux, V.; Anosov, V.; Austregesilo, A.; Badełek, B.; Balestra, F.; Barth, J.; Baum, G.; Beck, R.; Bedfer, Y.; Berlin, A.; Bernhard, J.; Bertini, R.; Bicker, K.; Bieling, J.; Birsa, R.; Bisplinghoff, J.; Bodlak, M.; Boer, M.; Bordalo, P.; Bradamante, F.; Braun, C.; Bravar, A.; Bressan, A.; Büchele, M.; Burtin, E.; Capozza, L.; Chiosso, M.; Chung, S. U.; Cicuttin, A.; Crespo, M. L.; Curiel, Q.; Dalla Torre, S.; Dasgupta, S. S.; Dasgupta, S.; Denisov, O. Yu.; Donskov, S. V.; Doshita, N.; Duic, V.; Dünnweber, W.; Dziewiecki, M.; Efremov, A.; Elia, C.; Eversheim, P. D.; Eyrich, W.; Faessler, M.; Ferrero, A.; Filin, A.; Finger, M.; Finger, M.; Fischer, H.; Franco, C.; du Fresne von Hohenesche, N.; Friedrich, J. M.; Frolov, V.; Garfagnini, R.; Gautheron, F.; Gavrichtchouk, O. P.; Gerassimov, S.; Geyer, R.; Giorgi, M.; Gnesi, I.; Gobbo, B.; Goertz, S.; Gorzellik, M.; Grabmüller, S.; Grasso, A.; Grube, B.; Gushterski, R.; Guskov, A.; Guthörl, T.; Haas, F.; von Harrach, D.; Hahne, D.; Hashimoto, R.; Heinsius, F. H.; Herrmann, F.; Heß, C.; Hinterberger, F.; Höppner, Ch.; Horikawa, N.; d'Hose, N.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jary, V.; Jasinski, P.; Joerg, P.; Joosten, R.; Kabuß, E.; Kang, D.; Ketzer, B.; Khaustov, G. V.; Khokhlov, Yu. A.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koivuniemi, J. H.; Kolosov, V. N.; Kondo, K.; Königsmann, K.; Konorov, I.; Konstantinov, V. F.; Kotzinian, A. M.; Kouznetsov, O.; Kral, Z.; Krämer, M.; Kroumchtein, Z. V.; Kuchinski, N.; Kunne, F.; Kurek, K.; Kurjata, R. P.; Lednev, A. A.; Lehmann, A.; Levorato, S.; Lichtenstadt, J.; Maggiora, A.; Magnon, A.; Makke, N.; Mallot, G. K.; Marchand, C.; Martin, A.; Marzec, J.; Matousek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.; Meyer, W.; Michigami, T.; Mikhailov, Yu. V.; Miyachi, Y.; Nagaytsev, A.; Nagel, T.; Nerling, F.; Neubert, S.; Neyret, D.; Nikolaenko, V. I.; Novy, J.; Nowak, W.-D.; Nunes, A. S.; Orlov, I.; Olshevsky, A. G.; Ostrick, M.; Panknin, R.; Panzieri, D.; Parsamyan, B.; Paul, S.; Pesek, M.; Peshekhonov, D.; Piragino, G.; Platchkov, S.; Pochodzalla, J.; Polak, J.; Polyakov, V. A.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Reicherz, G.; Rocco, E.; Rodionov, V.; Rondio, E.; Rossiyskaya, N. S.; Ryabchikov, D. I.; Samoylenko, V. D.; Sandacz, A.; Sapozhnikov, M. G.; Sarkar, S.; Savin, I. A.; Sbrizzai, G.; Schiavon, P.; Schill, C.; Schlüter, T.; Schmidt, A.; Schmidt, K.; Schmitt, L.; Schmïden, H.; Schönning, K.; Schopferer, S.; Schott, M.; Shevchenko, O. Yu.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Sosio, S.; Sozzi, F.; Srnka, A.; Steiger, L.; Stolarski, M.; Sulc, M.; Sulej, R.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Takekawa, S.; Ter Wolbeek, J.; Tessaro, S.; Tessarotto, F.; Thibaud, F.; Uhl, S.; Uman, I.; Vandenbroucke, M.; Virius, M.; Vondra, J.; Wang, L.; Weisrock, T.; Wilfert, M.; Windmolders, R.; Wiślicki, W.; Wollny, H.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Zhuravlev, N.; Ziembicki, M.

    2014-04-01

    Exclusive production of ρ0 mesons was studied at the COMPASS experiment by scattering 160 GeV/c muons off transversely polarised protons. Five single-spin and three double-spin azimuthal asymmetries were measured as a function of Q2, x, or pT2. The sin ϕS asymmetry is found to be -0.019±0.008(stat.)±0.003(syst.). All other asymmetries are also found to be of small magnitude and consistent with zero within experimental uncertainties. Very recent calculations using a GPD-based model agree well with the present results. The data is interpreted as evidence for the existence of chiral-odd, transverse generalized parton distributions.

  14. Bessel-Weighted Asymmetries in Semi Inclusive Deep Inelastic Scattering

    SciTech Connect

    D. Boer, L. Gamberg, B.U. Musch, A. Prokudin

    2011-10-01

    The concept of weighted asymmetries is revisited for semi-inclusive deep inelastic scattering. We consider the cross section in Fourier space, conjugate to the outgoing hadron's transverse momentum, where convolutions of transverse momentum dependent parton distribution functions and fragmentation functions become simple products. Individual asymmetric terms in the cross section can be projected out by means of a generalized set of weights involving Bessel functions. Advantages of employing these Bessel weights are that they suppress (divergent) contributions from high transverse momentum and that soft factors cancel in (Bessel-) weighted asymmetries. Also, the resulting compact expressions immediately connect to previous work on evolution equations for transverse momentum dependent parton distribution and fragmentation functions and to quantities accessible in lattice QCD. Bessel weighted asymmetries are thus model independent observables that augment the description and our understanding of correlations of spin and momentum in nucleon structure.

  15. Transverse top quark polarization and the forward-backward asymmetry

    NASA Astrophysics Data System (ADS)

    Baumgart, Matthew; Tweedie, Brock

    2013-08-01

    The forward-backward asymmetry in top pair production at the Tevatron has long been in tension with the Standard Model prediction. One of the only viable new physics scenarios capable of explaining this anomaly is an s-channel axigluon-like resonance, with the quantum numbers of the gluon but with significant axial couplings to quarks. While such a resonance can lead to a clear bump or excess in the or dijet mass spectra, it may also simply be too broad to cleanly observe. Here, we point out that broad resonances generally lead to net top and antitop polarizations transverse to the production plane. This polarization is consistent with all discrete spacetime symmetries, and, analogous to the forward-backward asymmetry itself, is absent in QCD at leading order. Within the parameter space consistent with the asymmetry measurements, the induced polarization can be sizable, and might be observable at the Tevatron or the LHC.

  16. Line asymmetry in the Seyfert Galaxy NGC 3783

    NASA Technical Reports Server (NTRS)

    Ramirez, J. M.; Bautista, Manuel; Kallman, Timothy

    2005-01-01

    We have reanalyzed the 900 ks Chandra X-ray spectrum of NGC 3783, finding evidence on the asymmetry of the spectral absorption lines. The lines are fitted with a parametric expression that results from an analytical treatment of radiatively driven winds. The line asymmetry distribution derived from the spectrum is consistent with a non-spherical outflow with a finite optical depth. Within this scenario, our model explains the observed correlations between the line velocity shifts and the ionization parameter and between the line velocity shift and the line asymmetry. The present results may provide a framework for detailed testing of models for the dynamic and physical properties of warm absorber in Seyfert galaxies.

  17. Load Asymmetry Observed During Orion Main Parachute Inflation

    NASA Technical Reports Server (NTRS)

    Morris, Aaron L.; Taylor, Thomas; Olson, Leah

    2011-01-01

    The Crew Exploration Vehicle Parachute Assembly System (CPAS) has flight tested the first two generations of the Orion parachute program. Three of the second generation tests instrumented the dispersion bridles of the Main parachute with a Tension Measuring System. The goal of this load measurement was to better understand load asymmetry during the inflation process of a cluster of Main parachutes. The CPAS Main parachutes exhibit inflations that are much less symmetric than current parachute literature and design guides would indicate. This paper will examine loads data gathered on three cluster tests, quantify the degree of asymmetry observed, and contrast the results with published design guides. Additionally, the measured loads data will be correlated with videos of the parachute inflation to make inferences about the shape of the parachute and the relative load asymmetry. The goal of this inquiry and test program is to open a dialogue regarding asymmetrical parachute inflation load factors.

  18. Genetic basis of human left-right asymmetry disorders.

    PubMed

    Deng, Hao; Xia, Hong; Deng, Sheng

    2015-01-01

    Humans and other vertebrates exhibit left-right (LR) asymmetric arrangement of the internal organs, and failure to establish normal LR asymmetry leads to internal laterality disorders, including situs inversus and heterotaxy. Situs inversus is complete mirror-imaged arrangement of the internal organs along LR axis, whereas heterotaxy is abnormal arrangement of the internal thoraco-abdominal organs across LR axis of the body, most of which are associated with complex cardiovascular malformations. Both disorders are genetically heterogeneous with reduced penetrance, presumably because of monogenic, polygenic or multifactorial causes. Research in genetics of LR asymmetry disorders has been extremely prolific over the past 17 years, and a series of loci and disease genes involved in situs inversus and heterotaxy have been described. The review highlights the classification, chromosomal abnormalities, pathogenic genes and the possible mechanism of human LR asymmetry disorders. PMID:26258520

  19. Take your seats: leftward asymmetry in classroom seating choice.

    PubMed

    Harms, Victoria L; Poon, Lisa J O; Smith, Austen K; Elias, Lorin J

    2015-01-01

    Despite an overall body symmetry, human behavior is full of examples of asymmetry, from writing or gesturing to kissing and cradling. Prior research has revealed that theatre patrons show a bias towards sitting on the right side of a movie theatre. Two competing theories have attempted to explain this seating asymmetry: one posits that expectation of processing demand drives the bias; the other posits that basic motor asymmetries drive the bias. To test these theories we assessed the real-world classroom seating choices of university students using photographs. A bias for students to choose seats on the left side of the classroom was observed, in contrast to the right side bias observed in theatre seating studies. These results provide evidence in support of a processing-expectation bias. PMID:26347639

  20. Harmful situations, impure people: an attribution asymmetry across moral domains.

    PubMed

    Chakroff, Alek; Young, Liane

    2015-03-01

    People make inferences about the actions of others, assessing whether an act is best explained by person-based versus situation-based accounts. Here we examine people's explanations for norm violations in different domains: harmful acts (e.g., assault) and impure acts (e.g., incest). Across four studies, we find evidence for an attribution asymmetry: people endorse more person-based attributions for impure versus harmful acts. This attribution asymmetry is partly explained by the abnormality of impure versus harmful acts, but not by differences in the moral wrongness or the statistical frequency of these acts. Finally, this asymmetry persists even when the situational factors that lead an agent to act impurely are stipulated. These results suggest that, relative to harmful acts, impure acts are linked to person-based attributions. PMID:25490126