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Sample records for bioassembly asymmetry proximity

  1. 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.

  2. Bilateral Asymmetry in Upper Extremities Is More Pronounced in Distal Compared to Proximal Joints.

    PubMed

    Aune, T K; Ettema, G; Vereijken, B

    2016-01-01

    The authors' aim was to compare spatial and temporal accuracy in proximal versus distal joints in upper extremities. Given the morphological differences in corticospinal and corticomotoneuronal projections for proximal and distal muscles, they hypothesized that bilateral asymmetry would be larger for distal than for proximal joints. Twelve participants performed isolated flexion-extension movements with the shoulders and index fingers. Angular range of motion of finger and shoulder movements was kept constant. The results showed significant bilateral asymmetry for both proximal and distal joints for both spatial and temporal accuracy. More importantly, bilateral asymmetry was significantly larger for the index fingers than for the shoulders for both spatial and temporal variables, as hypothesized. These results at the behavioral level pave the way for further studies that combine direct measures of neural activation with behavioral measures to further illuminate the potential link between bilateral communication and laterality effects in motor performance.

  3. Metric dimensions of the proximal phalanges of the human hand and their relationship to side, position, and asymmetry.

    PubMed

    Garrido Varas, C E; Thompson, T J U

    2011-04-01

    The anatomy of the proximal phalanges of the human hand has been widely described. Nevertheless, when consulting osteology and anatomy publications, the general opinion of researchers is that siding and allocating the proximal phalanges with regard to finger position is difficult, if not impossible. We provide morphological criteria for determining the side of the proximal phalanges and a metric means of allocating a phalanx to a specific finger. This paper also quantifies the absolute and directional asymmetry found in phalanges within this sample. The sample studied consists of three groups, one modern and two archaeological. To investigate these, three measurements were taken-maximum length, maximum width at the base and maximum width at the head. It was found that phalanges could be assigned correctly to the side and finger of origin in 100% of the cases when the five phalanges of a given hand were present, and that this result dropped to 92% when allocating isolated phalanges. The means of the measurements taken were larger in the modern group and a constant relationship between the greater basal width of the second and the fourth proximal phalanges was found. 2010 Elsevier GmbH. All rights reserved.

  4. Asymmetry of Non-Volcanic Passive Margins Induced by the Proximity of a Craton

    NASA Astrophysics Data System (ADS)

    Andres-Martinez, M.; Perez-Gussinye, M.; Morgan, J. P.; Araujo, M. N.

    2015-12-01

    Symmetry of conjugated rifted margins is controlled by the rheology of the crust and the mantle, extension velocities and heterogeneities in the lithosphere. However, there is a lack of knowledge on how the feedbacks between these initial conditions influence the final architecture of passive margins and the polarity of the asymmetry. Here we focus on cratons as stiff heterogeneities which potentially induce asymmetry. For simplicity, we choose to address only non-volcanic rifted margins developed next to cratons, such as the Brazil-Congo and Australia-Antarctica margin pairs. In the South Atlantic case, where cratons are closer to the margins (north of Sao Francisco craton and north and south of Congo craton) the margins are narrow, while wide margins develop far away from cratons. Extreme asymmetry occurs where rifting takes place close to a craton in one margin (narrow) and a fold belt in the conjugate (wide). The same is observed for the Australia-Antarctic pair in the sector of Recherche basin, where the Australian margin is narrow next to the Yilgarn craton and widens towards the east as it lays further from the craton. We use numerical models in order to study how cratons induce asymmetry of conjugated rifted margins and affect the polarity of the asymmetry. We ran experiments with different lower crustal rheologies for a fold belt lithosphere in order to understand which rheologies 'naturally' result in asymmetric margins. We also ran experiments where a cratonic lithosphere is placed next to a fold belt lithosphere, and where rifting is initiated by a weak seed in the fold belt at different distances from the craton. We found that where some fold belt experiments result in symmetric margins, their equivalent experiments with craton result in asymmetric margins. Furthermore, strong- and intermediate-rheology experiments with cratons showcase narrow margins in the craton side and wide margins on the fold belt side. We also observe that the distance from the

  5. Asymmetry in cricket song: female preference and proximate mechanism of discrimination.

    PubMed

    Hirtenlehner, Stefan; Küng, Saskia; Kainz, Franz; Römer, Heiner

    2013-06-01

    Subtle random deviations from perfect symmetry in bilateral traits are suggested to signal reduced phenotypic and genetic quality of a sender, but little is known about the related receiver mechanisms for discriminating symmetrical from asymmetrical traits. Here, we investigated these mechanisms in behavioural and neurophysiological experiments in the Mediterranean field cricket, Gryllus bimaculatus. A downward frequency modulation at the end of each syllable in the calling song has been suggested to indicate morphological asymmetry in sound radiating structures between left and right forewings. Even under ideal laboratory conditions on a trackball system, female crickets only discriminated between songs of symmetrical and asymmetrical males in two-choice experiments at carrier frequencies of 4.4 kHz and a large modulation depth of 600 and 800 Hz. Under these conditions they preferred the pure-tone calling songs over the modulated (asymmetrical) alternative, whereas no preference was observed at carrier frequencies of 4.9 and 5.2 kHz. These preferences correlate well with the responses of a pair of identified auditory interneurons (AN1), known for their importance in female phonotaxis. The AN1 interneuron is tuned to an average frequency of 4.9 kHz, and the roll-off towards lower and higher frequencies determines the magnitude of responses to pure-tone and frequency-modulated calling songs. The difference in response magnitude between the two neurons appears to drive the decision of females towards the song alternatives. We discuss the relevance of song differences based on asymmetry in the morphology of song-producing structures under natural conditions.

  6. Transepicondylar axes for femoral component rotation might produce flexion asymmetry during total knee arthroplasty in knees with proximal tibia vara.

    PubMed

    Park, Il Seok; Ong, Alvin; Nam, Chang Hyun; Ahn, Nong Kyum; Ahn, Hye Sun; Lee, Su Chan; Jung, Kwang Am

    2014-03-01

    Adequate rotation of the femoral component in total knee arthroplasty is mandatory for prevention of numerous adverse sequelae. Therefore, we investigate whether there is the distal femoral deformity in knees with tibia vara. The purpose of this study was to evaluate the reliability of the transepicondylar axis as a rotational landmark in knees with tibia vara. We retrospectively reviewed and selected 101 osteoarthritic knees with proximal tibia vara and 150 osteoarthritic knees without tibia vara for inclusion in this study. The transepicondylar axis (TEA), anteroposterior (AP) axis and posterior condylar (PC) line were measured using the axial image from magnetic resonance imaging axial images. We compared the external rotation angle of the TEA relative to the PC line between groups in order to investigate the presence of distal femoral anatomical adaptation in the tibia vara group. The TEA in the tibia vara group had 6.1º of external rotation relative to the PC line, which was not significantly different from the 6.0º of external rotation in the non-tibia vara group. The line perpendicular to the AP axis in the tibia vara group had 6.1º of external rotation relative to the PC line, which was not significantly different from the 5.4º of external rotation in the non-tibia vara group. Distal femoral geometry was unaffected by the tibia vara deformity. The use of transepicondylar axes in determining femoral rotation may produce flexion asymmetry in knees with tibia vara. Level III. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Layer-by-layer bioassembly of cellularized polylactic acid porous membranes for bone tissue engineering.

    PubMed

    Guduric, Vera; Metz, Carole; Siadous, Robin; Bareille, Reine; Levato, Riccardo; Engel, Elisabeth; Fricain, Jean-Christophe; Devillard, Raphaël; Luzanin, Ognjan; Catros, Sylvain

    2017-05-01

    The conventional tissue engineering is based on seeding of macroporous scaffold on its surface ("top-down" approach). The main limitation is poor cell viability in the middle of the scaffold due to poor diffusion of oxygen and nutrients and insufficient vascularization. Layer-by-Layer (LBL) bioassembly is based on "bottom-up" approach, which considers assembly of small cellularized blocks. The aim of this work was to evaluate proliferation and differentiation of human bone marrow stromal cells (HBMSCs) and endothelial progenitor cells (EPCs) in two and three dimensions (2D, 3D) using a LBL assembly of polylactic acid (PLA) scaffolds fabricated by 3D printing. 2D experiments have shown maintain of cell viability on PLA, especially when a co-cuture system was used, as well as adequate morphology of seeded cells. Early osteoblastic and endothelial differentiations were observed and cell proliferation was increased after 7 days of culture. In 3D, cell migration was observed between layers of LBL constructs, as well as an osteoblastic differentiation. These results indicate that LBL assembly of PLA layers could be suitable for BTE, in order to promote homogenous cell distribution inside the scaffold and gene expression specific to the cells implanted in the case of co-culture system.

  8. Motor-based microprobe powered by bio-assembled catalase for motion detection of DNA.

    PubMed

    Xie, Yuzhe; Fu, Shizhe; Wu, Jie; Lei, Jianping; Ju, Huangxian

    2017-01-15

    A motor-based microprobe is proposed using a tubular microengine powered by bio-assembled enzyme as catalyst and exploited for washing-free detection of DNA through motion readout. The microprobe is fabricated by assembling a catalase layer on the inner surface of poly(3,4-ethylenedioxythiophene)/Au (PEDOT/Au) microtube through DNA conjugate, which is responsible for the biocatalytic bubble propulsion. The sensing concept of the microprobe relies on the target-induced release of catalase through the DNA strand-replacement hybridization, which decreases the amount of enzyme assembled on microtube to slow down the movement of the microprobe. Therefore, the motion speed is negatively correlated with the target concentration. At the optimal conditions, the microprobe can conveniently distinguish the concentration of specific DNA in a range of 0.5-10µM without any washing and separation step. This microprobe can be prepared in batch with good reproducibility and stability, and its motion speed can be conveniently visualized by optical microscope. The proposed motor-based microprobe and its dynamic sensing method provide a novel platform for the development of intelligent microprobe and clinical diagnostic strategy.

  9. Bio-assembled, piezoelectric prawn shell made self-powered wearable sensor for non-invasive physiological signal monitoring

    NASA Astrophysics Data System (ADS)

    Ghosh, Sujoy Kumar; Mandal, Dipankar

    2017-03-01

    A human interactive self-powered wearable sensor is designed using waste by-product prawn shells. The structural origin of intrinsic piezoelectric characteristics of bio-assembled chitin nanofibers has been investigated. It allows the prawn shell to make a tactile sensor that performs also as a highly durable mechanical energy harvester/nanogenerator. The feasibility and fundamental physics of self-powered consumer electronics even from human perception is highlighted by prawn shells made nanogenerator (PSNG). High fidelity and non-invasive monitoring of vital signs, such as radial artery pulse wave and coughing actions, may lead to the potential use of PSNG for early intervention. It is presumed that PSNG has enormous future aspects in real-time as well as remote health care assessment.

  10. Proximal Nephron

    PubMed Central

    Zhuo, Jia L.; Li, Xiao C.

    2013-01-01

    The kidney plays a fundamental role in maintaining body salt and fluid balance and blood pressure homeostasis through the actions of its proximal and distal tubular segments of nephrons. However, proximal tubules are well recognized to exert a more prominent role than distal counterparts. Proximal tubules are responsible for reabsorbing approximately 65% of filtered load and most, if not all, of filtered amino acids, glucose, solutes, and low molecular weight proteins. Proximal tubules also play a key role in regulating acid-base balance by reabsorbing approximately 80% of filtered bicarbonate. The purpose of this review article is to provide a comprehensive overview of new insights and perspectives into current understanding of proximal tubules of nephrons, with an emphasis on the ultrastructure, molecular biology, cellular and integrative physiology, and the underlying signaling transduction mechanisms. The review is divided into three closely related sections. The first section focuses on the classification of nephrons and recent perspectives on the potential role of nephron numbers in human health and diseases. The second section reviews recent research on the structural and biochemical basis of proximal tubular function. The final section provides a comprehensive overview of new insights and perspectives in the physiological regulation of proximal tubular transport by vasoactive hormones. In the latter section, attention is particularly paid to new insights and perspectives learnt from recent cloning of transporters, development of transgenic animals with knockout or knockin of a particular gene of interest, and mapping of signaling pathways using microarrays and/or physiological proteomic approaches. PMID:23897681

  11. Hemispheric Asymmetries in Children.

    ERIC Educational Resources Information Center

    Lewandowski, Lawrence

    1982-01-01

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

  12. Hemispheric Asymmetries in Children.

    ERIC Educational Resources Information Center

    Lewandowski, Lawrence

    1982-01-01

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

  13. Universal freezing of asymmetry

    NASA Astrophysics Data System (ADS)

    Zhang, Da-Jian; Yu, Xiao-Dong; Huang, Hua-Lin; Tong, D. M.

    2017-02-01

    Asymmetry of quantum states is a useful resource in applications such as quantum metrology, quantum communication, and reference frame alignment. However, asymmetry of a state tends to be degraded in physical scenarios where environment-induced noise is described by covariant operations, e.g., open systems constrained by superselection rules, and such degradations weaken the abilities of the state to implement quantum information processing tasks. In this paper, we investigate under which dynamical conditions asymmetry of a state is totally unaffected by the noise described by covariant operations. We find that all asymmetry measures are frozen for a state under a covariant operation if and only if the relative entropy of asymmetry is frozen for the state. Our finding reveals the existence of universal freezing of asymmetry, and provides a necessary and sufficient condition under which asymmetry is totally unaffected by the noise.

  14. Proximity fuze

    SciTech Connect

    Harrison, T.R.

    1989-08-22

    A proximity fuze system is described. It includes an optical ranging apparatus, a detonation circuit controlled by the optical ranging apparatus, and an explosive charge detonated by the detonation circuit. The optical ranging apparatus includes a pulsed laser light source for generating target ranging light pulses and optical reference light pulses. A single lens directs ranging pulses to a target and collects reflected light from the target. An optical fiber bundle is used for delaying the optical reference pulses to correspond to a predetermined distance from the target. The optical ranging apparatus includes circuitry for providing a first signal depending upon the light pulses reflected from the target, a second signal depending upon the light pulses from the optical delay fiber bundle, and an output signal when the first and second signals coincide with each other. The output signal occurs when the distance from the target is equal to the predetermined distance from the target. Additional circuitry distinguishes pulses reflected from the target from background solar radiation.

  15. Proximity fuze

    DOEpatents

    Harrison, T.R.

    1987-07-10

    A proximity fuze system includes an optical ranging apparatus, a detonation circuit controlled by the optical ranging apparatus, and an explosive charge detonated by the detonation circuit. The optical ranging apparatus includes a pulsed laser light source for generating target ranging light pulses and optical reference light pulses. A single lens directs ranging pulses to a target and collects reflected light from the target. An optical fiber bundle is used for delaying the optical reference pulses to correspond to a predetermined distance from the target. The optical ranging apparatus includes circuitry for providing a first signal depending upon the light pulses reflected from the target, a second signal depending upon the light pulses from the optical delay fiber bundle, and an output signal when the first and second signals coincide with each other. The output signal occurs when the distance from the target is equal to the predetermined distance from the target. Additional circuitry distinguishes pulses reflected from the target from background solar radiation. 3 figs.

  16. Proximity fuze

    DOEpatents

    Harrison, Thomas R.

    1989-08-22

    A proximity fuze system includes an optical ranging apparatus, a detonation circuit controlled by the optical ranging apparatus, and an explosive charge detonated by the detonation cirtcuit. The optical ranging apparatus includes a pulsed laser light source for generating target ranging light pulses and optical reference light pulses. A single lens directs ranging pulses to a target and collects reflected light from the target. An optical fiber bundle is used for delaying the optical reference pulses to correspond to a predetermined distance from the target. The optical ranging apparatus includes circuitry for providing a first signal depending upon the light pulses reflected from the target, a second signal depending upon the light pulses from the optical delay fiber bundle, and an output signal when the first and second signals coincide with each other. The output signal occurs when the distance from the target is equal to the predetermined distance form the target. Additional circuitry distinguishes pulses reflected from the target from background solar radiation.

  17. The Principles of Asymmetry

    DTIC Science & Technology

    2005-05-26

    THE PRINCIPLES OF ASYMMETRY A monograph presented to the Faculty of the US Army School of Advanced Military Studies in...DATES COVERED Monograph 4. TITLE AND SUBTITLE The Principles pf Asymmetry 5. FUNDING NUMBERS 6. AUTHOR(S) Stephen D. Pomper Major, USA 7... principles of asymmetry. The ultimate goal of producing principles should allow soldiers to better appreciate a difficult, but important concept in

  18. Asymmetries at the Tevatron

    SciTech Connect

    Bartos, Pavol

    2014-10-28

    In this report, we summarize the latest results of the top-quark pair production asymmetry and present the new result of bottom-quark pair production asymmetry. By looking at the results obtained by the CDF experiment, one can see a discrepancy in both $t\\bar{t}$ inclusive and lepton-based measurements. The D0 results of the $t\\bar{t}$ production asymmetry are compatible with the standard-model predictions as well as with the CDF results. The CDF measurement of $b\\bar{b}$ production asymmetry presents consistency with both zero and with the standard-model predictions.

  19. Asymmetry of Blinking

    PubMed Central

    Kassem, Iris S.; Evinger, Craig

    2012-01-01

    Purpose Too investigate asymmetry in eyelid movements with blinking, the stability of the asymmetry, and its modifiability in normal humans. Methods Differences in the start time and amplitude between the two eyelids were assessed for voluntary blinks and reflex blinks evoked by supraorbital trigeminal nerve stimulation. These variables were also measured before and up to 18 months after 2 hours of unilateral upper lid restraint. Results With voluntary blinks, one eyelid consistently began to close earlier and made a larger eyelid movement than the other eyelid. Stimulation of the supraorbital branch of the trigeminal nerve evoked relatively larger amplitude blinks in one eyelid that correlated with the asymmetries of voluntary blinks. There was a continuum of eyelid asymmetry across all subjects that was stable and independent of other biological asymmetries, such as handedness. Briefly reducing eyelid mobility created a long-lasting change in eyelid asymmetry with blinking. Conclusions Eyelid asymmetry results from differences in the excitability of motoneurons in the left and right facial motor nuclei and does not appear to involve asymmetries in cortical inputs to the brain stem. Because adaptive processes modify the motoneuron excitability that creates eyelid asymmetry, these processes may underlie changes in blinking associated with facial palsy and may play a role in the development of disorders that affect one side of the face, such as hemifacial spasm. PMID:16384962

  20. 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…

  1. Lowering of Asymmetry

    NASA Astrophysics Data System (ADS)

    Pandey, K. K.; Hiremath, K. M.; Yellaiah, G.

    2017-03-01

    Asymmetry, a well established fact, can be extracted from various solar atmospheric activity indices. Although asymmetry is being localized within short time scale, it also persists at different time scales. In the present study we examine the character and nature of asymmetry at various time scales by optimizing the data set, in units of Carrington Rotations (CRs), for Sunspot Area (SA) and soft X-ray flare index (FI SXR). We find from three solar cycles (21-23) that at a small time scale (viz., daily, CRs and monthly) activity appears to be asymmetric with less significance. At larger time scales (≥01 CRs) strength of asymmetry enhances. Number of significant asymmetry points probably depends upon the solar heights. For different combination of data, asymmetry strength appears to be lowered at certain periods ˜06, ˜12, ˜18 CRs (164, 327 and 492 days i.e., harmonics of ˜1.3 years. Owing to similar behavior of emergence of magnetic flux, it is conjectured that emergence of flux on the surface probably contributes to the asymmetry of the solar activity.

  2. Proximal Tibial Bone Graft

    MedlinePlus

    ... All Site Content AOFAS / FootCareMD / Treatments Proximal Tibial Bone Graft Page Content What is a bone graft? Bone grafts may be needed for various ... the proximal tibia. What is a proximal tibial bone graft? Proximal tibial bone graft (PTBG) is a ...

  3. Comments on biological asymmetry.

    PubMed

    Opitz, J M; Utkus, A

    2001-07-15

    Gross forms of asymmetry of biological structure, hence of development, are generally considered abnormalities of conformation with "perfect" symmetry, whether bilateral or radial, being regarded as the "ideal" form. This notion, primarily a cultural deceit of neo-Platonic origin, can easily be shown to be wrong or at best only skin-deep by any student of anatomy or surgery who finds the heart not in the midline but, most of the time on the left, liver on the right, gut coiled and disposed in a certain direction with appendix in the right lower quadrant, and so forth. Indeed, since the beginning of Amphioxus, a major effect of evolutionary developmental modification has been the abolition of the visceral symmetry which characterized this cephalochordate with introduction of a specific pattern of asymmetry called laterality determination. This embryonic process, which is beginning to yield its universal molecular basis, is probably not responsible for another type of biological phenomenon designated fluctuating asymmetry well known to anthropologists (on the basis of quantitative studies of morphometric traits of teeth, appendicular skeleton, dermatoglyphics) and well-known to the ancients who in their most beautiful Hellenistic sculptures introduced deliberate asymmetries into facial structure and expression. Photographic images constructed of 2 right or 2 left facial halves may differ to a starling degree from the authentic face (Fig. 1). The relatively random nature of fluctuating asymmetry makes it less likely to be under strong natural selection. 1 Middle panel: Frontal view of face of a normal man. Left panel: "Artificial" face constructed out of two right halves of the same face. Right panel: Face constructed out of two left halves. A careful study of the right and left panels makes it easier to appreciate the actual degree of asymmetry present in the unaltered middle image/face. However, in addition to laterality determination and fluctuating asymmetry

  4. 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.

  5. Cerebral asymmetry in schizophrenia.

    PubMed

    Oertel-Knöchel, Viola; Linden, David E J

    2011-10-01

    The hemispheres of the human brain are anatomically and functionally asymmetric, and many cognitive and motor functions such as language and handedness are lateralized. This review examines anatomical, psychological, and physiological approaches to the understanding of separate hemispheric functions and their integration. The concept of hemispheric laterality plays a central role in current neuropsychological and pathophysiological models of schizophrenia. Reduced hemispheric asymmetry has also been reported for other mental disorders, for example, bipolar disorder. Recent research reflects an increasing interest in the molecular and population genetics of laterality and its potential link with animal models of schizophrenia. The authors review the principles of laterality and brain asymmetry and discuss the evidence for changes in asymmetry in schizophrenia and other mental disorders.

  6. 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.

  7. 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.

  8. Early signs of brain asymmetry.

    PubMed

    Corballis, Michael C

    2013-11-01

    A new study shows a leftward asymmetry of the choroid plexus in two-thirds of first-trimester human fetuses. This is the earliest brain asymmetry so far identified and may be a precursor to other asymmetries, including that of the temporal planum, which is evident from the 31st week of gestation.

  9. Neutrino helicity asymmetries in leptogenesis

    SciTech Connect

    Bento, Luis; Santos, Francisco C.

    2005-05-01

    It is pointed out that the heavy singlet neutrinos characteristic of leptogenesis develop asymmetries in the abundances of the two helicity states as a result of the same mechanism that generates asymmetries in the standard lepton sector. Neutrinos and standard leptons interchange asymmetries in collisions with each other. It is shown that an appropriate quantum number, B-L{sup '}, combining baryon, lepton and neutrino asymmetries, is not violated as fast as the standard B-L. This suppresses the washout effects relevant for the derivation of the final baryon asymmetry. One presents detailed calculations for the period of neutrino thermal production in the framework of the singlet seesaw mechanism.

  10. 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

  11. Bessel Weighted Asymmetries

    SciTech Connect

    Avakian, Harut; Gamberg, Leonard; Rossi, Patrizia; Prokudin, Alexei

    2016-05-01

    We review the concept of Bessel weighted asymmetries for semi-inclusive deep inelastic scattering and focus on 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. The procedure is applied to studies of the double longitudinal spin asymmetry in semi-inclusive deep inelastic scattering using a new dedicated Monte Carlo generator which includes quark intrinsic transverse momentum within the generalized parton model. We observe a few percent systematic offset of the Bessel-weighted asymmetry obtained from Monte Carlo extraction compared to input model calculations, which is due to the limitations imposed by the energy and momentum conservation at the given energy and hard scale Q2. We find that the Bessel weighting technique provides a powerful and reliable tool to study the Fourier transform of TMDs with controlled systematics due to experimental acceptances and resolutions with different TMD model inputs.

  12. 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

  13. White matter microstructure asymmetry: effects of volume asymmetry on fractional anisotropy asymmetry.

    PubMed

    Takao, H; Hayashi, N; Ohtomo, K

    2013-02-12

    Diffusion tensor imaging (DTI) provides information regarding white matter microstructure; however, macroscopic fiber architectures can affect DTI measures. A larger brain (fiber tract) has a 'relatively' smaller voxel size, and the voxels are less likely to contain more than one fiber orientation and more likely to have higher fractional anisotropy (FA). Previous DTI studies report left-to-right differences in the white matter; however, these may reflect true microscopic differences or be caused purely by volume differences. Using tract-based spatial statistics, we investigated left-to-right differences in white matter microstructure across the whole brain. Voxel-wise analysis revealed a large number of white matter volume asymmetries, including leftward asymmetry of the arcuate fasciculus and cingulum. In many white matter regions, FA asymmetry was positively correlated with volume asymmetry. Voxel-wise analysis with adjustment for volume asymmetry revealed many white matter FA asymmetries, including leftward asymmetry of the arcuate fasciculus and cingulum. The voxel-wise analysis showed a reduced number of regions with significant FA asymmetry compared with analysis performed without adjustment for volume asymmetry; however, the overall trend of the results was unchanged. The results of the present study suggest that these FA asymmetries are not caused by volume differences and reflect microscopic differences in the white matter.

  14. Proximal humerus fractures.

    PubMed

    Price, Matthew C; Horn, Pamela L; Latshaw, James C

    2013-01-01

    Proximal humerus fractures are among the most common fractures associated with osteoporosis. With an aging population, incidence of these fractures will only increase. The proximal humerus not only forms the lateral portion of the shoulder articulation but also has significant associations with musculoskeletal and neurovascular structures. As a result, fractures of the proximal humerus can significantly impact not only the function of the shoulder joint, but the health and function of the entire upper extremity as well. Understanding of these fractures, the management options, and associated nursing care, can help reduce morbidity rate and improve functional outcomes.

  15. Position sense asymmetry.

    PubMed

    Adamo, Diane E; Martin, Bernard J

    2009-01-01

    Asymmetries in upper limb position sense have been explained in the context of a left limb advantage derived from differences in hemispheric specialization in the processing of kinesthetic information. However, it is not clearly understood how the comparison of perceptual information associated with passive limb displacement and the corresponding matching movement resulting from the execution of a motor command contributes to these differences. In the present study, upper limb position sense was investigated in 12 right-hand-dominant young adults performing wrist position matching tasks which varied in terms of interhemispheric transfer, memory retrieval and whether the reference position was provided by the same or opposite limb. Right and left hand absolute matching errors were similar when the reference and matching positions were produced by the same hand but were 36% greater when matching the reference position with the opposite hand. When examining the constant errors generated from matching movements made with the same hand that provided the reference, the right and left hand matching errors (approximately 3 degrees) were similar. However, when matching with the opposite limb, a large overshoot (P < 0.05) characterized the error when the right hand matched the left hand reference while a large undershoot (P < 0.05) characterized the error when the left hand matched the right hand reference. The overshoot and undershoot were of similar magnitude (approximately 4 degrees). Although asymmetries in the central processing of proprioceptive information such as interhemispheric transfer may exist, the present study suggests that asymmetries in position sense predominantly result from a difference in the "gain of the respective proprioceptive sensory-motor loops". This new hypothesis is strongly supported by a dual-linear model representing the right and left hand sensory-motor systems as well as morphological and physiological data.

  16. Large-Scale Photometric Asymmetry in Galaxy Spin Patterns

    NASA Astrophysics Data System (ADS)

    Shamir, Lior

    2017-09-01

    Spin patterns of spiral galaxies can be broadly separated into galaxies with clockwise (Z-wise) patterns and galaxies with counterclockwise (S-wise) spin patterns. While the differences between these patterns are visually noticeable, they are a matter of the perspective of the observer, and therefore in a sufficiently large universe no other differences are expected between galaxies with Z-wise and S-wise patterns. Here, large datasets of spiral galaxies separated by their spin patterns are used to show that spiral galaxies with Z-wise spin patterns are photometrically different from spiral galaxies with S-wise patterns. That asymmetry changes based on the direction of observation, such that the observed asymmetry in one hemisphere is aligned with the inverse observed asymmetry in the opposite hemisphere. The results are consistent across different sky surveys (SDSS and PanSTARRS) and analysis methods. The proximity of the most probable asymmetry axis to the galactic pole suggests that the asymmetry might be driven by relativistic beaming. Annotated data from SDSS and PanSTARRS are publicly available.

  17. Rubber friction directional asymmetry

    NASA Astrophysics Data System (ADS)

    Tiwari, A.; Dorogin, L.; Steenwyk, B.; Warhadpande, A.; Motamedi, M.; Fortunato, G.; Ciaravola, V.; Persson, B. N. J.

    2016-12-01

    In rubber friction studies it is usually assumed that the friction force does not depend on the sliding direction, unless the substrate has anisotropic properties, like a steel surface grinded in one direction. Here we will present experimental results for rubber friction, where we observe a strong asymmetry between forward and backward sliding, where forward and backward refer to the run-in direction of the rubber block. The observed effect could be very important in tire applications, where directional properties of the rubber friction could be induced during braking.

  18. Design and analysis of nanoscale bioassemblies.

    PubMed

    Clark, Jarrod; Singer, Elizabeth M; Korns, Darlynn R; Smith, Steven S

    2004-06-01

    Bionanotechnology is an emerging field in nanotechnology. In general, it uses concepts from chemistry, biochemistry, and molecular biology to identify components and processes for the construction of self-assembling materials and devices. Distant goals of the science of bionanotechnology range from developing programmable nanoscale devices that can sample or alter their environments to developing assemblies capable of Darwinian evolution. At the heart of these approaches is the concept of the production of supramolecular assemblies (SMAs; also known as supramolecular aggregates) by programmed self-assembly in an aqueous medium. Ordered arrays, planar and closed-shell tilings, dynamic machines, and switches have been designed and constructed by using DNA-DNA, protein-protein, and protein-nucleic acid biospecificities. We review the designs and the analytical techniques that have been employed in the production of SMAs that do not occur in nature.

  19. Functional Nanomaterials for Environmental Applications and Bioassemblies

    NASA Astrophysics Data System (ADS)

    Nguyen, Michelle Anne

    The rational design of nanomaterials has yielded new technologies that have revolutionized numerous diverse fields. The work detailed herein first describes the application of photocatalytic nanomaterials towards the environmental remediation of harmful toxins. Specifically, a low-temperature solution-phase synthetic route for size-controlled Cu2O octahedra particles was developed, and these materials were evaluated as catalysts for the photocatalytic degradation of aromatic organic compounds. Moreover, cubic Cu2O/Pd composite structures were fabricated and demonstrated to be effective photocatalysts for the generation of H2 and the reductive dehalogenation of polychlorinated biphenyls, well-known carcinogens present at many contaminated sites around the world. This photocatalytic approach to environmental remediation exemplifies the adaptation of light-driven technologies and sustainable practices to energy-intensive catalytic systems. In addition, this work also investigates the organic/inorganic interface of peptide-mediated Au nanoparticles as a means to identify rational design principles for materials binding peptide sequences for the advancement of stimuli-responsive bionanoassemblies. Factors inherent to peptide sequences that can promote strong materials-binding affinity and/or effective nanoparticle stabilization capability were identified in order to progress biomimetic technologies. These findings were elucidated using a combinational approach of peptide binding experiments to Au in partnership with molecular dynamics simulations. Overall, this work demonstrates the growing applications of nanomaterials in remediation technologies and aids in the understanding of the origins of peptide material affinity and nanoparticle stabilization.

  20. Exchange asymmetry in experimental settings

    Treesearch

    Thomas C. Brown; Mark D. Morrison; Jacob A. Benfield; Gretchen Nurse Rainbolt; Paul A. Bell

    2015-01-01

    We review past trading experiments and present 11 new experiments designed to show how the trading rate responds to alterations of the experimental procedure. In agreement with earlier studies, results show that if the trade decision is converted to one resembling a choice between goods the exchange asymmetry disappears, but otherwise the asymmetry is...

  1. 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.

  2. Lip asymmetry and smile aesthetics.

    PubMed

    Batwa, Waeil; McDonald, Fraser; Cash, Alex

    2013-11-01

    Objective : To determine if lip asymmetry can affect lip aesthetics. Setting and Participants : A group of dentists (n = 40) and cleft patients (n = 40) were recruited from the dental hospital and cleft service. Interventions : Still photographic digital images of lips and teeth were manipulated to produce a computerized gradient of smile appearance with different degrees of upper-lip vertical asymmetry. These five photographs (with 0 mm representing "symmetry," and 1, 2, 2.5, and 3 mm, asymmetries) were assessed by participants using a 5-point Likert scale. Statistics : Descriptive statistics in addition to chi-square test were used to analyze the data. In order to satisfy the requirement of the chi-square test, the five smile ratings were reduced to three. Results : Lip asymmetry did affect relative smile aesthetics, as determined by dentists and cleft patients. Both the dentists and cleft patients rated the 0-mm photograph more attractive than the 2.5-mm and 3-mm smiles (P < .05). The 0-, 1-, and 2-mm smiles were indistinguishable for both dentists and cleft patients. Conclusion : Lip asymmetry affects smile aesthetics. However, cleft patients and dentists were tolerant of minor asymmetries. This suggests that small degrees of lip asymmetry do not affect relative smile aesthetics as much as large degrees of lip asymmetry (2.5 mm or more).

  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. Hypnosis and hemispheric asymmetry.

    PubMed

    Naish, Peter L N

    2010-03-01

    Participants of low and high hypnotic susceptibility were tested on a temporal order judgement task, both with and without hypnosis. Judgements were made of the order of presentation of light flashes appearing in first one hemi-field then the other. There were differences in the inter-stimulus intervals required accurately to report the order, depending upon which hemi-field led. This asymmetry was most marked in hypnotically susceptible participants and reversed when they were hypnotized. This implies not only that brain activity changes in hypnosis, but also that there is a difference in brain function between people of low and high hypnotic susceptibility. The latter exhibited a faster-acting left hemisphere in the waking state, but faster right when hypnotized.

  5. Dental arch asymmetry

    PubMed Central

    Al-Zubair, Nabil Muhsen

    2014-01-01

    Objective: This study was conducted to assess the dental arch asymmetry in a Yemeni sample aged (18-25) years. Materials and Methods: The investigation involved clinical examination of 1479 adults; only 253 (129 females, 124 males) out of the total sample were selected to fulfill the criteria for the study sample. Study models were constructed and evaluated to measure mandibular arch dimensions. Three linear distances were utilized on each side on the dental arch: Incisal-canine distance, canine-molar distance and incisal-molar distance, which represent the dental arch segmental measurements. Results: When applying “t-test” at P < 0.05, no significant differences were found between the right and left canine-molar, incisal-canine and incisal-molar distances in both dental arches for both sexes. The greater variation (0.30 mm) was observed between right and left canine-molar distance in the maxillary dental arch in male and the smaller (0.04 mm) in the mandibular dental arch between the right and left canine-molar distance in females. Conclusion: The findings of the present study revealed a symmetrical pattern of dental arches, since the right and left sides showed no statistically significant difference. In general, it can be observed that the measurements related to the central incisors and canines have the widest range of reading and give the impression that the location of central incisor and canines to each other and to other teeth is the strongest factor in determining the dental arch asymmetry. PMID:24966774

  6. Capacitive proximity sensor

    DOEpatents

    Kronberg, James W.

    1994-01-01

    A proximity sensor based on a closed field circuit. The circuit comprises a ring oscillator using a symmetrical array of plates that creates an oscillating displacement current. The displacement current varies as a function of the proximity of objects to the plate array. Preferably the plates are in the form of a group of three pair of symmetric plates having a common center, arranged in a hexagonal pattern with opposing plates linked as a pair. The sensor produces logic level pulses suitable for interfacing with a computer or process controller. The proximity sensor can be incorporated into a load cell, a differential pressure gauge, or a device for measuring the consistency of a characteristic of a material where a variation in the consistency causes the dielectric constant of the material to change.

  7. Capacitive proximity sensor

    DOEpatents

    Kronberg, J.W.

    1994-05-31

    A proximity sensor based on a closed field circuit is disclosed. The circuit comprises a ring oscillator using a symmetrical array of plates that creates an oscillating displacement current. The displacement current varies as a function of the proximity of objects to the plate array. Preferably the plates are in the form of a group of three pair of symmetric plates having a common center, arranged in a hexagonal pattern with opposing plates linked as a pair. The sensor produces logic level pulses suitable for interfacing with a computer or process controller. The proximity sensor can be incorporated into a load cell, a differential pressure gauge, or a device for measuring the consistency of a characteristic of a material where a variation in the consistency causes the dielectric constant of the material to change. 14 figs.

  8. Proximal Hamstring Repair Strength

    PubMed Central

    Harvey, Margaret Ann; Singh, Hardeep; Obopilwe, Elifho; Charette, Ryan; Miller, Suzanne

    2015-01-01

    Background: Proximal hamstring repair for complete ruptures has become a common treatment. There is no consensus in the literature about postoperative rehabilitation protocols following proximal hamstring repair. Some protocols describe bracing to prevent hip flexion or knee extension while others describe no immobilization. There are currently no biomechanical studies evaluating proximal hamstring repairs; nor are there any studies evaluating the effect of different hip flexion angles on these repairs. Hypothesis: As hip flexion increases from 0° to 90°, there will be a greater gap with cyclical loading. Study Design: Controlled laboratory study. Methods: Proximal hamstring insertions were detached from the ischial tuberosity in 24 cadavers and were repaired with 3 single-loaded suture anchors in the hamstring footprint with a Krakow suture technique. Cyclic loading from 10 to 125 N at 1 Hz was then performed for 0°, 45°, and 90° of hip flexion for 1500 cycles. Gap formation, stiffness, yield load, ultimate load, and energy to ultimate load were compared between groups using paired t tests. Results: Cyclic loading demonstrated the least amount of gap formation (P < .05) at 0° of hip flexion (2.39 mm) and most at 90° of hip flexion (4.19 mm). There was no significant difference in ultimate load between hip flexion angles (326, 309, and 338 N at 0°, 45°, and 90°, respectively). The most common mode of failure occurred with knot/suture failure (n = 17). Conclusion: Increasing hip flexion from 0° to 90° increases the displacement across proximal hamstring repairs. Postoperative bracing that limits hip flexion should be considered. Clinical Relevance: Repetitive motion involving hip flexion after a proximal hamstring repair may cause compromise of the repair. PMID:26665049

  9. 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

  10. Proximate Analysis of Coal

    ERIC Educational Resources Information Center

    Donahue, Craig J.; Rais, Elizabeth A.

    2009-01-01

    This lab experiment illustrates the use of thermogravimetric analysis (TGA) to perform proximate analysis on a series of coal samples of different rank. Peat and coke are also examined. A total of four exercises are described. These are dry exercises as students interpret previously recorded scans. The weight percent moisture, volatile matter,…

  11. Traumatic proximal tibiofibular dislocation.

    PubMed

    Burgos, J; Alvarez-Montero, R; Gonzalez-Herranz, P; Rapariz, J M

    1997-01-01

    Proximal tibiofibular dislocation is an exceptional lesion. Rarer still is its presentation in childhood. We describe the clinical case of a 6-year-old boy, the victim of a road accident. He had a tibiofibular dislocation associated with a metaphyseal fracture of the tibia.

  12. Steerable Capacitive Proximity Sensor

    NASA Technical Reports Server (NTRS)

    Jenstrom, Del T.; Mcconnell, Robert L.

    1994-01-01

    Steerable capacitive proximity sensor of "capaciflector" type based partly on sensing units described in GSC-13377 and GSC-13475. Position of maximum sensitivity adjusted without moving sensor. Voltage of each driven shield adjusted separately to concentrate sensing electric field more toward one side or other.

  13. Proximate Analysis of Coal

    ERIC Educational Resources Information Center

    Donahue, Craig J.; Rais, Elizabeth A.

    2009-01-01

    This lab experiment illustrates the use of thermogravimetric analysis (TGA) to perform proximate analysis on a series of coal samples of different rank. Peat and coke are also examined. A total of four exercises are described. These are dry exercises as students interpret previously recorded scans. The weight percent moisture, volatile matter,…

  14. 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.

  15. Subacute diabetic proximal neuropathy

    NASA Technical Reports Server (NTRS)

    Pascoe, M. K.; Low, P. A.; Windebank, A. J.; Litchy, W. J.

    1997-01-01

    OBJECTIVE: To evaluate the clinical, electrophysiologic, autonomic, and neuropathologic characteristics and the natural history of subacute diabetic proximal neuropathy and its response to immunotherapy. MATERIAL AND METHODS: For the 12-year period from 1983 to 1995, we conducted a retrospective review of medical records of Mayo Clinic patients with diabetes who had subacute onset and progression of proximal weakness. The responses of treated versus untreated patients were compared statistically. RESULTS: During the designated study period, 44 patients with subacute diabetic proximal neuropathy were encountered. Most patients were middle-aged or elderly, and no sex preponderance was noted. The proximal muscle weakness often was associated with reduced or absent lower extremity reflexes. Associated weight loss was a common finding. Frequently, patients had some evidence of demyelination on nerve conduction studies, but it invariably was accompanied by concomitant axonal degeneration. The cerebrospinal fluid protein concentration was usually increased. Diffuse and substantial autonomic failure was generally present. In most cases, a sural nerve biopsy specimen suggested demyelination, although evidence of an inflammatory infiltrate was less common. Of 12 patients who received treatment (with prednisone, intravenous immune globulin, or plasma exchange), 9 had improvement of their conditions, but 17 of 29 untreated patients (59%) with follow-up also eventually had improvement, albeit at a much slower rate. Improvement was usually incomplete. CONCLUSION: We suggest that the entity of subacute diabetic proximal neuropathy is an extensive and severe variant of bilateral lumbosacral radiculoplexopathy, with some features suggestive of an immune-mediated cause. It differs from chronic inflammatory demyelinating polyradiculoneuropathy in that most cases have a more restricted distribution and seem to be monophasic and self-limiting. The efficacy of immunotherapy is unproved

  16. Subacute diabetic proximal neuropathy

    NASA Technical Reports Server (NTRS)

    Pascoe, M. K.; Low, P. A.; Windebank, A. J.; Litchy, W. J.

    1997-01-01

    OBJECTIVE: To evaluate the clinical, electrophysiologic, autonomic, and neuropathologic characteristics and the natural history of subacute diabetic proximal neuropathy and its response to immunotherapy. MATERIAL AND METHODS: For the 12-year period from 1983 to 1995, we conducted a retrospective review of medical records of Mayo Clinic patients with diabetes who had subacute onset and progression of proximal weakness. The responses of treated versus untreated patients were compared statistically. RESULTS: During the designated study period, 44 patients with subacute diabetic proximal neuropathy were encountered. Most patients were middle-aged or elderly, and no sex preponderance was noted. The proximal muscle weakness often was associated with reduced or absent lower extremity reflexes. Associated weight loss was a common finding. Frequently, patients had some evidence of demyelination on nerve conduction studies, but it invariably was accompanied by concomitant axonal degeneration. The cerebrospinal fluid protein concentration was usually increased. Diffuse and substantial autonomic failure was generally present. In most cases, a sural nerve biopsy specimen suggested demyelination, although evidence of an inflammatory infiltrate was less common. Of 12 patients who received treatment (with prednisone, intravenous immune globulin, or plasma exchange), 9 had improvement of their conditions, but 17 of 29 untreated patients (59%) with follow-up also eventually had improvement, albeit at a much slower rate. Improvement was usually incomplete. CONCLUSION: We suggest that the entity of subacute diabetic proximal neuropathy is an extensive and severe variant of bilateral lumbosacral radiculoplexopathy, with some features suggestive of an immune-mediated cause. It differs from chronic inflammatory demyelinating polyradiculoneuropathy in that most cases have a more restricted distribution and seem to be monophasic and self-limiting. The efficacy of immunotherapy is unproved

  17. Intrasubject corneal thickness asymmetry.

    PubMed

    Khachikian, Stephen S; Belin, Michael W; Ciolino, Joseph B

    2008-06-01

    To establish the normal distribution for intrasubject (right eye/left eye) central corneal pachymetry in a refractive surgery population. A retrospective analysis was performed on 1448 eyes of 724 consecutive patients evaluated for refractive surgery. Pachymetric data were obtained from the Pentacam Eye Scanner. Right and left eye pachymetry values were compared for the corneal apex, pupil center, and thinnest point. Statistical analysis was performed to determine normal levels of variance. The average apex reading was 539.3+/-36.8 microm, median 542 microm, and mode 539 microm (range: 411 to 664 microm). Values for the pupil center (average 538.7 microm) and thinnest point (average 536.1 microm) followed a similar distribution. The average pachymetry difference between fellow eyes was 8.8+/-7.2 microm at the apex, 8.9+/-8.3 microm at the pupil center, and 9.0+/-8.3 microm at the thinnest region. Individuals with a greater than 23.2 microm apical pachymetry difference represent less than 5% of the population. Individuals with an apical difference greater than 30.4 microm represent less than 0.5%. Pachymetric asymmetry outside the normal range should alert the clinician to examine for other parameters that are more established refractive surgery risk factors.

  18. [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.

  19. Asymmetry and dyslexia.

    PubMed

    Leonard, Christiana M; Eckert, Mark A

    2008-01-01

    Developmental language disorders are characterized by a maturational trajectory that deviates or lags that of normal children. Given the wide variation in the rate of normal language development, diagnosis and classification of these disorders poses severe problems for the clinician. Our laboratory has been searching for anatomical signatures that could aid the development of a neurobiologically based classification. Quantitative analysis of the magnetic resonance imaging (MRI) brain scans of a series of samples of children and adults with reading and language disorders has identified two clusters with contrasting anatomical and reading profiles. Individuals with small symmetrical brain structures tend to have deficits in multiple domains of written and oral language whereas those with larger asymmetrical structures are more likely to have the isolated phonological deficits seen in adults with compensated dyslexia. Surprisingly, the anatomical risk factors that define these clusters do not form a continuum of increasing severity but deviate in opposite directions from normal. Individuals with moderate brain size and asymmetry typically demonstrate the best overall performance. Further research should determine if phonological impairments in the two clusters are associated with differing genetic and environmental risk factors requiring different types of intervention.

  20. Beam normal spin asymmetries: Theory

    SciTech Connect

    M. Vanderhaeghen

    2007-06-01

    The beam normal spin asymmetry in elastic electron-nucleon scattering is discussed. This beam normal spin asymmetry depends on the imaginary part of two-photon exchange processes between electron and nucleon, and measures the non-forward structure functions of the nucleon. After briefly reviewing the theoretical formalism, we discuss calculations in the threshold region, in the resonance region, as well as in the diffractive region, corresponding with high energy and forward angles.

  1. Electrodermal asymmetry during human sleep.

    PubMed

    Freixa i Baqué, E; de Bonis, M

    1983-01-01

    The bilateral spontaneous electrodermal activity (EDA) of four paid volunteer male students was recorded during three consecutive complete nights (after a habituation night). The results showed that: (a) there was a high proportion of electrodermal asymmetry (80%) during human sleep; (b) there were no significant differences in asymmetry between sleep stages; (c) electrodermal laterality during sleep seems to be under a random effects model; and (d) laterality appears to be an unreliable parameter. These results are discussed in terms of the activation theory.

  2. Intrachromosomal karyotype asymmetry in Orchidaceae

    PubMed Central

    Medeiros-Neto, Enoque; Nollet, Felipe; Moraes, Ana Paula; Felix, Leonardo P.

    2017-01-01

    Abstract The asymmetry indexes have helped cytotaxonomists to interpret and classify plant karyotypes for species delimitation efforts. However, there is no consensus about the best method to calculate the intrachromosomal asymmetry. The present study aimed to compare different intrachromosomal asymmetry indexes in order to indicate which are more efficient for the estimation of asymmetry in different groups of orchids. Besides, we aimed to compare our results with the Orchidaceae phylogenetic proposal to test the hypothesis of Stebbins (1971). Through a literature review, karyotypes were selected and analyzed comparatively with ideal karyotypes in a cluster analysis. All karyotypes showed some level of interchromosomal asymmetry, ranging from slightly asymmetric to moderately asymmetric. The five tested intrachromosomal asymmetry indexes indicated Sarcoglottis grandiflora as the species with the most symmetrical karyotype and Christensonella pachyphylla with the most asymmetrical karyotype. In the cluster analysis, the largest number of species were grouped with the intermediary ideal karyotypes B or C. Considering our results, we recommend the combined use of at least two indexes, especially Ask% or A1 with Syi, for cytotaxonomic analysis in groups of orchids. In an evolutionary perspective, our results support Stebbins’ hypothesis that asymmetric karyotypes derive from a symmetric karyotypes. PMID:28644507

  3. Intrachromosomal karyotype asymmetry in Orchidaceae.

    PubMed

    Medeiros-Neto, Enoque; Nollet, Felipe; Moraes, Ana Paula; Felix, Leonardo P

    2017-01-01

    The asymmetry indexes have helped cytotaxonomists to interpret and classify plant karyotypes for species delimitation efforts. However, there is no consensus about the best method to calculate the intrachromosomal asymmetry. The present study aimed to compare different intrachromosomal asymmetry indexes in order to indicate which are more efficient for the estimation of asymmetry in different groups of orchids. Besides, we aimed to compare our results with the Orchidaceae phylogenetic proposal to test the hypothesis of Stebbins (1971). Through a literature review, karyotypes were selected and analyzed comparatively with ideal karyotypes in a cluster analysis. All karyotypes showed some level of interchromosomal asymmetry, ranging from slightly asymmetric to moderately asymmetric. The five tested intrachromosomal asymmetry indexes indicated Sarcoglottis grandiflora as the species with the most symmetrical karyotype and Christensonella pachyphylla with the most asymmetrical karyotype. In the cluster analysis, the largest number of species were grouped with the intermediary ideal karyotypes B or C. Considering our results, we recommend the combined use of at least two indexes, especially Ask% or A1 with Syi, for cytotaxonomic analysis in groups of orchids. In an evolutionary perspective, our results support Stebbins' hypothesis that asymmetric karyotypes derive from a symmetric karyotypes.

  4. Proximity Networks and Epidemics

    NASA Astrophysics Data System (ADS)

    Guclu, Hasan; Toroczkai, Zoltán

    2007-03-01

    We presented the basis of a framework to account for the dynamics of contacts in epidemic processes, through the notion of dynamic proximity graphs. By varying the integration time-parameter T, which is the period of infectivity one can give a simple account for some of the differences in the observed contact networks for different diseases, such as smallpox, or AIDS. Our simplistic model also seems to shed some light on the shape of the degree distribution of the measured people-people contact network from the EPISIM data. We certainly do not claim that the simplistic graph integration model above is a good model for dynamic contact graphs. It only contains the essential ingredients for such processes to produce a qualitative agreement with some observations. We expect that further refinements and extensions to this picture, in particular deriving the link-probabilities in the dynamic proximity graph from more realistic contact dynamics should improve the agreement between models and data.

  5. Cerebral asymmetry in insomnia sufferers.

    PubMed

    St-Jean, Geneviève; Turcotte, Isabelle; Bastien, Célyne H

    2012-01-01

    Cerebral asymmetry is used to describe the differences in electroencephalographic activity between regions of the brain. The objective of this study was to document frontal, central, and parietal asymmetry in psychophysiological (Psy-I) and paradoxical (Para-I) insomnia sufferers as well as good sleeper (GS) controls, and to compare their patterns of asymmetry to others already found in anxiety and depression. Additionally, asymmetry variations between nights were assessed. Participants were 17 Psy-I, 14 Para-I, and 19 GS (mean age = 40 years, SD = 9.4). They completed three nights of polysomnography (PSG) recordings following a clinical evaluation in a sleep laboratory. All sleep cycles of Nights 2 and 3 were retained for power spectral analysis. The absolute activity in frequency bands (0.00-125.00 Hz) was computed at multiple frontal, central, and parietal sites in rapid eye movement and non-rapid eye movement sleep to provide cerebral asymmetry measures. Mixed model ANOVAs were computed to assess differences between groups and nights. Correlations were performed with asymmetry and symptoms of depression and anxiety from self-reported questionnaires. Over the course of the two nights, Para-I tended to present hypoactivation of their left frontal region but hyperactivation of their right one compared with GS. As for Psy-I, they presented increased activation of their right parietal region compared with Para-I. Asymmetry at frontal, central, and parietal region differed between nights. On a more disrupted night of sleep, Psy-I had increased activity in their right parietal region while Para-I presented a decrease in cerebral activity in the right central region on their less disrupted night of sleep. Anxious and depressive symptoms did not correlate with asymmetry at any region. Therefore, Psy-I and Para-I present unique patterns of cerebral asymmetry that do not relate to depression or anxiety, and asymmetry varies between nights, maybe as a

  6. Karyotype asymmetry in Cynodon Rich. (Poaceae) accessions.

    PubMed

    Chiavegatto, R B; Paula, C M P; Souza Sobrinho, F; Benites, F R G; Techio, V H

    2016-12-02

    Cynodon is a genus of plants with forage potential that has attracted the interest of breeders. These species have high morphological variability in a large number of varieties and cytotypes, hampering identification. This study aimed to determine the karyotype asymmetry index among accessions of Cynodon to discriminate between them. Karyotype symmetry was based on three estimates, which were compared. The basic number for the genus is x = 9. The results of the chromosome count and DNA quantification, respectively, were as follows: two diploid accessions (2n = 2x = 18 and 1.08 ± 0.094 to 1.17 ± 0.036 pg DNA and ± standard deviation), one triploid accession (2n = 3x = 27 and 1.63 ± 0.017 pg DNA), four tetraploid accessions (2n = 4x = 36 and 1.88 ± 0.069 to 2.10 ± 0.07 pg DNA), and one pentaploid accession (2n = 5x = 45 and 2.55 ± 0.098 pg DNA). C. incompletus var. hirsutus had the longest total length of the haploid lot (29.05 µm), with chromosomes that ranged from 1.7 to 6.2 µm in length. On the basis of the karyotype asymmetry indices, the accessions were divided into two groups: 1) C. dactylon var. dactylon, C. transvaalensis, C. dactylon var. polevansii, three accessions of Cynodon sp, and C. nlemfuensis; and 2) C. incompletus var. hirsutus. This is the first description of tetraploidy in C. transvaalensis. The karyotypic data facilitated a determination of the degree of proximity between the accessions.

  7. Expected dipole asymmetry in CMB polarization

    SciTech Connect

    Namjoo, M.H.; Abolhasani, A.A.; Baghram, S.; Assadullahi, H.; Wands, D.; Firouzjahi, H. E-mail: abolhasani@ipm.ir E-mail: shant.baghramian@gmail.com E-mail: david.wands@port.ac.uk

    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.

  8. Geometric asymmetry driven Janus micromotors.

    PubMed

    Zhao, Guanjia; Pumera, Martin

    2014-10-07

    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.

  9. Rift asymmetry and continental uplift

    NASA Astrophysics Data System (ADS)

    Doglioni, Carlo; Carminati, Eugenio; Bonatti, Enrico

    2003-06-01

    The topography of ocean ridges and rifts show a distinct asymmetry. The eastern sides of the East Pacific Rise, the Mid-Atlantic Ridge, and the NW Indian Ridge are, on average, 100-300 m more elevated than the conjugate flank to the west. The asymmetry is maintained when bathymetry is plotted versus the square root of crustal age. A comparable topographic asymmetry occurs in the Red Sea and Baikal rifts where the "eastern" continental shoulders are more elevated. We suggest that depleted and lighter asthenosphere generated below the ocean ridge was shifted "eastward" relative to the lithosphere, determining a density deficit below the eastern flank. The eastward migration of the lighter Atlantic asthenosphere below the African continent could eventually have contributed to the anomalous postrift uplift of Africa. This model suggests that the "westward" drift of the lithosphere relative to the underlying mantle might be a global phenomenon.

  10. Echosonography with proximity sensors

    NASA Astrophysics Data System (ADS)

    Thaisiam, W.; Laithong, T.; Meekhun, S.; Chaiwathyothin, N.; Thanlarp, P.; Danworaphong, S.

    2013-03-01

    We propose the use of a commercial ultrasonic proximity sensor kit for profiling an altitude-varying surface by employing echosonography. The proximity sensor kit, two identical transducers together with its dedicated operating circuit, is used as a profiler for the construction of an image. Ultrasonic pulses are emitted from one of the transducers and received by the other. The time duration between the pulses allows us to determine the traveling distance of each pulse. In the experiment, the circuit is used with the addition of two copper wires for directing the outgoing and incoming signals to an oscilloscope. The time of flight of ultrasonic pulses can thus be determined. Square grids of 5 × 5 cm2 are made from fishing lines, forming pixels in the image. The grids are designed to hold the detection unit in place, about 30 cm above a flat surface. The surface to be imaged is constructed to be height varying and placed on the flat surface underneath the grids. Our result shows that an image of the profiled surface can be created by varying the location of the detection unit along the grid. We also investigate the deviation in relation to the time of flight of the ultrasonic pulse. Such an experiment should be valuable for conveying the concept of ultrasonic imaging to physical and medical science undergraduate students. Due to its simplicity, the setup could be made in any undergraduate laboratory relatively inexpensively and it requires no complex parts. The results illustrate the concept of echosonography.

  11. Proximity networks and epidemics

    NASA Astrophysics Data System (ADS)

    Toroczkai, Zoltán; Guclu, Hasan

    2007-05-01

    Disease spread in most biological populations requires the proximity of agents. In populations where the individuals have spatial mobility, the contact graph is generated by the “collision dynamics” of the agents, and thus the evolution of epidemics couples directly to the spatial dynamics of the population. We first briefly review the properties and the methodology of an agent-based simulation (EPISIMS) to model disease spread in realistic urban dynamic contact networks. Using the data generated by this simulation, we introduce the notion of dynamic proximity networks which takes into account the relevant time-scales for disease spread: contact duration, infectivity period, and rate of contact creation. This approach promises to be a good candidate for a unified treatment of epidemic types that are driven by agent collision dynamics. In particular, using a simple model, we show that it can account for the observed qualitative differences between the degree distributions of contact graphs of diseases with short infectivity period (such as air-transmitted diseases) or long infectivity periods (such as HIV).

  12. Magnetic asymmetries of unmagnetized planets

    NASA Technical Reports Server (NTRS)

    Brecht, Stephen H.

    1990-01-01

    This letter discusses the results produced by three-dimensional hybrid particle code simulations of the solar wind interaction with unmagnetized planets such as Venus and Mars. The solar wind velocity is perpendicular to the IMF in the cases studied. It is found that there are asymmetries in both the magnetic structure and shock location for spherical obstacles ranging in radius from 1000 km to 6000 km. The asymmetries found are due to differences in the electron and ion current paths (diamagnetic behavior). Mass loading of 0(+) was not included in these simulations.

  13. NRZ Data Asymmetry Corrector and Convolutional Encoder

    NASA Technical Reports Server (NTRS)

    Pfiffner, H. J.

    1983-01-01

    Circuit compensates for timing, amplitude and symmetry perturbations. Data asymmetry corrector and convolutional encoder regenerate data and clock signals in spite of signal variations such as data or clock asymmetry, phase errors, and amplitude variations, then encode data for transmission.

  14. Perspectives on asymmetry: the Erickson Lecture.

    PubMed

    Cohen, M Michael

    2012-12-01

    Topics discussed include asymmetry of the brain; prosopagnosia with asymmetric involvement; the blaspheming brain; effects of the numbers of X chromosomes on brain asymmetry; normal facial asymmetry; kissing asymmetry; left- and right-handedness; left-sided baby cradling; Nodal signaling and left/right asymmetry; primary cilium and left/right asymmetry in zebrafish; right/left asymmetry in snails; species differences in Shh and Fgf8; primary cilium in vertebrate asymmetry; Hedgehog signaling on the cilium; Wnt signaling on the cilium; situs solitus, situs inversus, and situs ambiguus (heterotaxy); ciliopathies; right-sided injuries in trilobites; unilateral ocular use in the octopus; fiddler crabs; scale-eating cichlids; narwhals; left-footed parrots; asymmetric whisker use in rats; and right-sided fatigue fractures in greyhounds.

  15. 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…

  16. How asymmetry in animals starts

    NASA Astrophysics Data System (ADS)

    Güntürkün, Onur

    2005-10-01

    This review aims to present a speculation about mechanisms that shape the brains of humans and other animals into an asymmetrical organization. To this end, I will proceed in two steps: first, I want to recapitulate evidence from various experiments that show that some but not all asymmetries of the avian brain result from a prehatch light stimulation asymmetry. This should make it clear that avian embryos have a genetic predisposition to turn their head to the right. This results in a higher level of prehatch light stimulation of their right eye. The concomitant left-right difference in sensory input alters the brain circuits of the animal for the entire lifespan in a lateralized way. In the second part of the paper I will present evidence that some of the asymmetries of the human brain take a similar ontogenetic path as those observed in birds. This review provides the evidence that critical ontogenetic processes discovered in animal models could also be involved in the ontogeny of human cerebral asymmetries.

  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. Some Properties of Fuzzy Soft Proximity Spaces

    PubMed Central

    Demir, İzzettin; Özbakır, Oya Bedre

    2015-01-01

    We study the fuzzy soft proximity spaces in Katsaras's sense. First, we show how a fuzzy soft topology is derived from a fuzzy soft proximity. Also, we define the notion of fuzzy soft δ-neighborhood in the fuzzy soft proximity space which offers an alternative approach to the study of fuzzy soft proximity spaces. Later, we obtain the initial fuzzy soft proximity determined by a family of fuzzy soft proximities. Finally, we investigate relationship between fuzzy soft proximities and proximities. PMID:25793224

  19. Some properties of fuzzy soft proximity spaces.

    PubMed

    Demir, İzzettin; Özbakır, Oya Bedre

    2015-01-01

    We study the fuzzy soft proximity spaces in Katsaras's sense. First, we show how a fuzzy soft topology is derived from a fuzzy soft proximity. Also, we define the notion of fuzzy soft δ-neighborhood in the fuzzy soft proximity space which offers an alternative approach to the study of fuzzy soft proximity spaces. Later, we obtain the initial fuzzy soft proximity determined by a family of fuzzy soft proximities. Finally, we investigate relationship between fuzzy soft proximities and proximities.

  20. Proximal Biceps Tenodesis

    PubMed Central

    Kovack, Thomas J.; Idoine, John D.; Jacob, Paul B.

    2014-01-01

    Purpose: To (1) better define the anatomy of the proximal shoulder in relation to the long head of the biceps tendon, (2) compare the length-tension relationship of the biceps tendon in the native shoulder with that after arthroscopic and open tenodesis techniques using interference screws, and (3) provide surgical recommendations for both procedures based on study findings. Study Design: Descriptive laboratory study. Methods: Twenty fresh-frozen cadaveric shoulders were dissected for analysis. Initial anatomic measurements involving the proximal long head of the biceps tendon (BT) were made, which included: the labral origin to the superior bicipital groove (LO-SBG), the total tendon length (TTL), the musculotendinous junction (MTJ) to the inferior pectoralis major tendon border, the MTJ to the superior pectoralis major tendon border, and the biceps tendon diameter (BTD) at 2 different tenodesis locations. These same measurements were made again after completing a simulated suprapectoral arthroscopic and open subpectoral tenodesis, both with interference screw fixation. Statistical comparisons were then made between the native anatomy and that after tenodesis, with the goal of assessing the accuracy of re-establishing the normal length-tension relationship of the long head of the BT after simulated arthroscopic suprapectoral and open subpectoral tenodesis with tenodesis screws. Results: For all cadavers, the mean TTL was 104.1 mm. For the arthroscopic suprapectoral technique, the mean LO-SBG was 33.6 mm, and the mean tendon resection length was 12.8 mm in males and 5.0 mm in females. The mean BTD was 6.35 mm at the arthroscopic suprapectoral tenodesis site and 5.75 mm at the open subpectoral tenodesis site. Males were found to have statistically longer TTL and LO-SBG measurements (111.6 vs 96.5 mm [P = .027] and 37.2 vs 30.0 mm [P = .009], respectively). In the native shoulder, the mean distances from the MTJ to the superior and inferior borders of the pectoralis

  1. Volumetric assessment of cerebral asymmetries in dogs.

    PubMed

    Siniscalchi, Marcello; Franchini, Delia; Pepe, Anna M; Sasso, Raffaella; Dimatteo, Salvatore; Vallortigara, Giorgio; Quaranta, Angelo

    2011-09-01

    In the present study we quantified volumetric brain asymmetries from computed tomography (CT) scans in 12 healthy dogs, using a semi-automated technique for assessing in vivo structure asymmetry. Volumetric assessment of asymmetrical cerebral lateral ventricle (ALV) was also investigated. Our results showed that seven dogs exhibited a right hemisphere significantly greater than the left, two dogs had a left-greater-than-right hemisphere asymmetry, and finally two dogs displayed no significant brain volumetric asymmetry. This right-biased hemispheric asymmetry supports data reported previously using post-mortem morphological studies in both dogs and other mammalian species.

  2. 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

  3. Planum temporale asymmetry in people who stutter.

    PubMed

    Gough, Patricia M; Connally, Emily L; Howell, Peter; Ward, David; Chesters, Jennifer; Watkins, Kate E

    2017-06-16

    Previous studies have reported that the planum temporale - a language-related structure that normally shows a leftward asymmetry - had reduced asymmetry in people who stutter (PWS) and reversed asymmetry in those with severe stuttering. These findings are consistent with the theory that altered language lateralization may be a cause or consequence of stuttering. Here, we re-examined these findings in a larger sample of PWS. We evaluated planum temporale asymmetry in structural MRI scans obtained from 67 PWS and 63 age-matched controls using: 1) manual measurements of the surface area; 2) voxel-based morphometry to automatically calculate grey matter density. We examined the influences of gender, age, and stuttering severity on planum temporale asymmetry. The size of the planum temporale and its asymmetry were not different in PWS compared with Controls using either the manual or the automated method. Both groups showed a significant leftwards asymmetry on average (about one-third of PWS and Controls showed rightward asymmetry). Importantly, and contrary to previous reports, the degree of asymmetry was not related to stuttering severity. In the manual measurements, women who stutter had a tendency towards rightwards asymmetry but men who stutter showed the same degree of leftwards asymmetry as male Controls. In the automated measurements, Controls showed a significant increase in leftwards asymmetry with age but this relationship was not observed in PWS. We conclude that reduced planum temporale asymmetry is not a prominent feature of the brain in PWS and that the asymmetry is unrelated to stuttering severity. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  4. Motor asymmetry in elite fencers.

    PubMed

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

    2015-01-01

    The authors previously reported that asymmetrical patterns of hand preference are updated and modified by present sensorimotor conditions. They examined whether participation in long-term training in the upper extremity sport fencing might modify arm selection and performance asymmetries. Eight fencers and eight nonfencers performed reaching movements under 3 experimental conditions: (a) nonchoice right, (b) nonchoice left, and (c) choice, either right or left arm as selected by subject. The nonchoice 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 group showed substantially greater symmetry in the performance and selection measures. These findings suggest that arm selection and performance asymmetries can be altered by intense long-term practice.

  5. Directional asymmetry in responses of local interneurons in the crayfish deutocerebrum to hydrodynamic stimulation of the lateral antennular flagellum.

    PubMed

    Mellon, DeForest; Humphrey, Joseph A C

    2007-09-01

    We have recorded spiking responses from single, bimodally sensitive local interneurons (Type I) in the crayfish deutocerebrum to hydrodynamic and odorant stimuli flowing in two directions past the lateral antennular flagellum. Changing the direction of seamless introductions (meaning, with minimal variations of fluid velocity magnitude) of odorant flow past the flagellum, from proximal-->distal to distal-->proximal, did not consistently affect the dose-dependent responses of Type I neurons. By contrast, changing the direction of an abruptly initiated flow of water (or odorant) past the flagellum resulted in consistently larger numbers of spikes in response to this hydrodynamic stimulation when the flow direction was proximal-->distal. This response asymmetry is discussed in relation to its possible relevance regarding antennular flicking behavior. The putative involvement of flagellar hydrodynamic receptors, the beaked hairs, and the hydrodynamic flow asymmetries they are exposed to, are examined theoretically in the accompanying paper.

  6. Condylar-mandibular asymmetry, a reality.

    PubMed

    Boratto, R; Gambardella, U; Micheletti, P; Pagliani, L; Preda, L; Hansson, T L

    2002-01-01

    The aim of this study is to evaluate the possibility to recognize a condylar-mandibular asymmetry through a panoramic radiograph. Results from a previous work, in which 100 skulls from the Museum of the Institute of Anatomy of the University of Pavia were studied and measured, showed the presence of asymmetry. Using the same skulls we examined the possible correlation between morphological and radiological data. We did not find out correlation's between the condylar asymmetry evaluated at the anatomical level and the radiological asymmetry which was indeed found. This is probably due to the different positioning of the jaws during the two different measuring processes. Nevertheless our results confirm the daily experience of dentistry: asymmetry of mandibular condyle can be one of the mayor causes for the asymmetry of the stomatognatic apparatus.

  7. Proximal trisomy 1q in a girl with developmental delay and minor anomalies

    SciTech Connect

    Furforo, L. |; Rittler, M.; Slavutsky, I.R.

    1996-09-06

    We report on a girl with developmental delay, macrocephaly, facial asymmetry, small downturned palpebral fissures, high and narrow palate, micrognathia, short neck, a heart defect, and unilateral renal agenesis. Cytogenetic analysis showed a proximal tandem duplication of the long arm of chromosome one (1q12{r_arrow}q21.3). This abnormality was suggested by G-and C-banding but it was specifically characterized by fluorescent in situ hybridization (FISH). Clinical findings in our patient are compared with those of the literature in an attempt to delineate the phenotype in patients with proximal 1q duplication. 12 refs., 4 figs., 1 tab.

  8. Write field asymmetry in perpendicular magnetic recording

    NASA Astrophysics Data System (ADS)

    Li, Zhanjie; Bai, Daniel Z.; Lin, Ed; Mao, Sining

    2012-04-01

    We present a systematic study of write field asymmetry by using micromagnetic modeling for a perpendicular magnetic recording (PMR) writer structure. Parameters investigated include initial magnetization condition, write current amplitude, write current frequency, and initial write current polarity. It is found that the write current amplitude and frequency (data rate) are the dominant factors that impact the field asymmetry. Lower write current amplitude and higher write current frequency will deteriorate the write field asymmetry, causing recording performance (such as bit error rate) degradation.

  9. Tools for proximal soil sensing

    USDA-ARS?s Scientific Manuscript database

    Proximal soil sensing (i.e. near-surface geophysical methods) are used to study soil phenomena across spatial scales. Geophysical methods exploit contrasts in physical properties (dielectric permittivity, apparent electrical conductivity or resistivity, magnetic susceptibility) to indirectly measur...

  10. Hirayama Disease with Proximal Involvement

    PubMed Central

    2016-01-01

    Hirayama disease is a slowly progressing benign motor neuron disease that affects the distal upper limb. A 29-year-old man visited the hospital with a 1-year history of weakened left proximal upper limb. He was diagnosed with Hirayama disease 9 years ago, while there was no further progression of the muscle weakness afterward. Atrophy and weakness was detected in proximal upper limb muscles. Magnetic resonance imaging and somatosensory evoked potentials were normal. Needle electromyography showed abnormal findings in proximal upper limb muscles. Our patient had Hirayama disease involving the proximal portion through secondary progression. Clinical manifestation and accurate electromyography may be useful for diagnosis. Rare cases with progression patterns as described here are helpful and have clinical meaning for clinicians. PMID:27550499

  11. Discharge Asymmetry in Delta Bifurcations

    NASA Astrophysics Data System (ADS)

    Salter, G.; Paola, C.; Voller, V. R.

    2015-12-01

    Distributary networks are formed by channels which bifurcate downstream in a river delta. Sediment and water fluxes are often split unequally in delta bifurcations. Understanding flux asymmetry in distributary networks is important for predicting how a delta will respond to sea-level rise. We present results of a quasi-1D model of a delta bifurcation. Consistent with previous results, in the absence of deposition, stable bifurcations may be either symmetric or asymmetric, depending on flow conditions. However, in a depositional setting, a stable asymmetric flow partitioning is no longer possible, as the dominant branch becomes less and less steep relative to the other branch. This feedback eventually causes the second branch to become favored. For the depositional case, we identify three regimes of bifurcation behavior: 1) stable symmetric bifurcation, 2) "soft" avulsions where the dominant branch switches without complete abandonment of the previous channel, and 3) complete avulsions where one branch is completely abandoned. In each case, the bifurcation is symmetric in the long-term average, but the latter two allow for short-term asymmetry. We find that keeping upstream sediment and water discharges fixed, as downstream channel length increases the regime shifts from symmetric to soft avulsions to complete avulsions. In the two avulsion regimes we examine the effect of upstream sediment and water discharges and downstream channel length on avulsion period and maximum discharge ratio. Finally, we compare numerical modeling results to a fixed-wall bifurcation experiment. As in the numerical model, the presence or absence of a downstream sink exerts a strong control on system behavior. If a sink is present, a bifurcation may be asymmetric indefinitely. Conversely, without a sink the system is depositional, and the feedback between sediment discharge asymmetry and slope causes the bifurcation to remain symmetric in the long-term average.

  12. The causes and ecological correlates of head scale asymmetry and fragmentation in a tropical snake.

    PubMed

    Brown, Gregory P; Madsen, Thomas; Dubey, Sylvain; Shine, Rick

    2017-09-12

    The challenge of identifying the proximate causes and ecological consequences of phenotypic variation can be facilitated by studying traits that are usually but not always bilaterally symmetrical; deviations from symmetry likely reflect disrupted embryogenesis. Based on a 19-year mark-recapture study of >1300 slatey-grey snakes (Stegonotus cucullatus) in tropical Australia, and incubation of >700 eggs, we document developmental and ecological correlates of two morphological traits: asymmetry and fragmentation of head scales. Asymmetry was directional (more scales on the left side) and was higher in individuals with lower heterozygosity, but was not heritable. In contrast, fragmentation was heritable and was higher in females than males. Both scale asymmetry and fragmentation were increased by rapid embryogenesis but were not affected by hydric conditions during incubation. Snakes with asymmetry and fragmentation exhibited slightly lower survival and increased (sex-specific) movements, and females with more scale fragmentation produced smaller eggs. Counterintuitively, snakes with more asymmetry had higher growth rates (possibly reflecting trade-offs with other traits), and snakes with more fragmentation had fewer parasites (possibly due to lower feeding rates). Our data paint an unusually detailed picture of the complex genetic and environmental factors that, by disrupting early embryonic development, generate variations in morphology that have detectable correlations with ecological performance.

  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. Atypical alpha asymmetry in adults with ADHD.

    PubMed

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

    2009-08-01

    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 asymmetry has been associated with ADHD-like traits such as reduced reward responsiveness, a lack of inhibition toward aversive experience, and increased approach behaviors, and previous work has indicated increased rightward alpha asymmetry in children with ADHD. The current study explores whether increased rightward alpha asymmetry is also evident in adults with ADHD. We assessed low (8-10 Hz) and high (10-12 Hz) alpha asymmetry in adults with ADHD (n=29) versus controls (n=62) during baseline and cognitive activation conditions for nine homologous electrode pairs along the anterior-posterior axis. Seven results emerged (p<.05) showing increased rightward alpha asymmetry in adults with ADHD. This occurred in three specific electrode pairs across two testing conditions, and five of six results occurred in the lower alpha band. Finally, post hoc analysis indicated that increased rightward alpha asymmetry was generally associated with greater numbers of ADHD symptoms--with a possible parietal association for inattentive and a fronto-temporal association for hyperactivity symptoms. Increased rightward alpha asymmetry previously observed in children with ADHD appears to be a developmentally persistent feature of ADHD.

  15. Measuring Asymmetry in Time-Stamped Phylogenies.

    PubMed

    Dearlove, Bethany L; Frost, Simon D W

    2015-07-01

    Previous work has shown that asymmetry in viral phylogenies may be indicative of heterogeneity in transmission, for example due to acute HIV infection or the presence of 'core groups' with higher contact rates. Hence, evidence of asymmetry may provide clues to underlying population structure, even when direct information on, for example, stage of infection or contact rates, are missing. However, current tests of phylogenetic asymmetry (a) suffer from false positives when the tips of the phylogeny are sampled at different times and (b) only test for global asymmetry, and hence suffer from false negatives when asymmetry is localised to part of a phylogeny. We present a simple permutation-based approach for testing for asymmetry in a phylogeny, where we compare the observed phylogeny with random phylogenies with the same sampling and coalescence times, to reduce the false positive rate. We also demonstrate how profiles of measures of asymmetry calculated over a range of evolutionary times in the phylogeny can be used to identify local asymmetry. In combination with different metrics of asymmetry, this combined approach offers detailed insights of how phylogenies reconstructed from real viral datasets may deviate from the simplistic assumptions of commonly used coalescent and birth-death process models.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. Induction of asymmetry into homodimers.

    PubMed

    Bardsley, B; Cho, Y R; Westwell, M S; Williams, D H

    1998-01-01

    The self-regulation of biological signalling receptors via homodimerization is discussed in relation to the symmetry changes occurring when these receptors bind their target ligand. The idea of positive and negative cooperativity between dimerization and ligand binding, mediated by changes in the symmetry of the system as a source of signalling control is considered; an analogy made with the homodimerization of a glycopeptide antibiotic, ristocetin A, which displays negative cooperativity. Finally, the regulation of the bacterial aspartate receptor and the human growth hormone receptor is discussed as a function of ligand-induced asymmetry.

  1. Agonistic asymmetries and the foraging ecology of Bald Eagles

    USGS Publications Warehouse

    Knight, Richard L.; Skagen, Susan Knight

    1988-01-01

    We investigated the effects of both asymmetries and differing food levels on contest outcomes of wintering Bald Eagles (Haliaeetus leucocephalus) feeding on chum salmon (Oncorhynchus keta) carcasses. Large eagles, regardless of age, were more successful in pirating than smaller eagles. Small pirating eagles were usually unsuccessful unless they were adults attempting to supplant other small eagles. Feeding eagles were more successful in defeating pirating eagles according to (1) whether their heads were up to prior to a pirating attempt, (2) how long their heads had been up, and (3) whether they displayed. During periods of food scarcity pirating eagles were less successful, a fact attributed in a proximate sense to the increase incidence of retaliation by feeding birds. When food was scarce and eagles had a choice between scavenging the pirating, they chose to scavenge more often. Body size appears to be an important factor in determining social dominance and influencing differences in foraging modes of wintering Bald Eagles.

  2. Fluctuating asymmetry and psychometric intelligence.

    PubMed Central

    Furlow, F B; Armijo-Prewitt, T; Gangestad, S W; Thornhill, R

    1997-01-01

    Little is known about the genetic nature of human psychometric intelligence (IQ), but it is widely assumed that IQ's heritability is at loci for intelligence per se. We present evidence consistent with a hypothesis that interindividual IQ differences are partly due to heritable vulnerabilities to environmental sources of developmental stress, an indirect genetic mechanism for the heritability of IQ. Using fluctuating asymmetry (FA) of the body (the asymmetry resulting from errors in the development of normally symmetrical bilateral traits under stressful conditions), we estimated the relative developmental instability of 112 undergraduates and administered to them Cattell's culture fair intelligence test (CFIT). A subsequent replication on 128 students was performed. In both samples, FA correlated negatively and significantly with CFIT scores. We propose two non-mutually exclusive physiological explanations for this correlation. First, external body FA may correlate negatively with the developmental integrity of the brain. Second, individual energy budget allocations and/or low metabolic efficiency in high-FA individuals may lower IQ scores. We review the data on IQ in light of our findings and conclude that improving developmental quality may increase average IQ in future generations. PMID:9265189

  3. Strangeness asymmetry in the proton

    NASA Astrophysics Data System (ADS)

    Alberg, Mary

    2015-04-01

    Strangeness asymmetry in the proton may arise from fluctuations of the proton into meson-baryon pairs. The leading contributions to proton strangeness are from the KΛ , KΣ , K* Λ and K* Σ states. We use a Fock state expansion of the proton in terms of these pairs to represent the strange meson cloud. We determine the strangeness distributions of the proton in a hybrid convolution model, in which the fluctuations are represented either by light-cone wave functions or meson-baryon splitting functions. For the parton distributions of the s(s) quarks in the bare baryons(mesons) of the Fock states, we use light cone wave functions or our statistical model, which expands the bare hadrons in terms of quark-gluon states. The momentum distributions of the s and s quarks in each Fock state differ because they are constituents of different hadrons. We present our results for proton strangeness asymmetry, and compare them to NuTeV and to global parton distributions. This research has been supported in part by NSF Award 1205686.

  4. 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

  5. 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

  6. Right-Left Asymmetries in the Brain

    ERIC Educational Resources Information Center

    Galaburda, Albert M.; And Others

    1978-01-01

    Reports on structural asymmetrics between the hemispheres which are found in the human brain. Auditory region and Sylvian Fissure asymmetry have also been observed in the fetus and in other primates. Describes research which has correlated asymmetries with hand preference, certain childhood learning disabilities and some dementing illnesses of…

  7. beta. -decay asymmetry of the free neutron

    SciTech Connect

    Bopp, P.; Dubbers, D.; Klemt, E.; Last, J.; Schuetze, H.; Weibler, W.; Freedman, S.J.; Schaerpf, O.

    1983-01-01

    The ..beta..-decay of polarized neutrons has been studied with the new superconducting spectrometer PERKEO at the ILL. The energy dependence of the ..beta..-decay asymmetry has been measured for the first time. From the measured ..beta..-asymmetry parameter we obtain a new value for the ratio of weak coupling constants g/sub A//g/sub V/. 11 references.

  8. The evolution and genetics of cerebral asymmetry.

    PubMed

    Corballis, Michael C

    2009-04-12

    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.

  9. Asymmetries and Variations in Jupiter's Magnetosphere

    NASA Technical Reports Server (NTRS)

    Khurana, Krishan K.

    2003-01-01

    The investigation was carried out to infer the influence of solar wind on Jupiter's magnetosphere through studies of asymmetries and variations in the magnetosphere. We used the magnetic field observations from all of the pre-Galileo spacecraft and from the Galileo Prime and extended missions to understand asymmetries in magnetic field and various current systems in the magnetosphere.

  10. 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

  11. 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…

  12. Jet Asymmetry in High Energy Diffractive Production

    SciTech Connect

    Brodsky, Stanley J.

    2000-09-15

    The authors propose the asymmetry in the fractional energy of charm versus anticharm jets produced in high energy diffractive photoproduction as a sensitive test of the interference of the Odderon (C = {minus}) and Pomeron (C = +) exchange amplitudes in QCD. If measured at HERA, this asymmetry could provide the first experimental evidence of the Odderon.

  13. 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…

  14. Right-Left Asymmetries in the Brain

    ERIC Educational Resources Information Center

    Galaburda, Albert M.; And Others

    1978-01-01

    Reports on structural asymmetrics between the hemispheres which are found in the human brain. Auditory region and Sylvian Fissure asymmetry have also been observed in the fetus and in other primates. Describes research which has correlated asymmetries with hand preference, certain childhood learning disabilities and some dementing illnesses of…

  15. 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…

  16. 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…

  17. Indefinite Proximity Learning: A Review.

    PubMed

    Schleif, Frank-Michael; Tino, Peter

    2015-10-01

    Efficient learning of a data analysis task strongly depends on the data representation. Most methods rely on (symmetric) similarity or dissimilarity representations by means of metric inner products or distances, providing easy access to powerful mathematical formalisms like kernel or branch-and-bound approaches. Similarities and dissimilarities are, however, often naturally obtained by nonmetric proximity measures that cannot easily be handled by classical learning algorithms. Major efforts have been undertaken to provide approaches that can either directly be used for such data or to make standard methods available for these types of data. We provide a comprehensive survey for the field of learning with nonmetric proximities. First, we introduce the formalism used in nonmetric spaces and motivate specific treatments for nonmetric proximity data. Second, we provide a systematization of the various approaches. For each category of approaches, we provide a comparative discussion of the individual algorithms and address complexity issues and generalization properties. In a summarizing section, we provide a larger experimental study for the majority of the algorithms on standard data sets. We also address the problem of large-scale proximity learning, which is often overlooked in this context and of major importance to make the method relevant in practice. The algorithms we discuss are in general applicable for proximity-based clustering, one-class classification, classification, regression, and embedding approaches. In the experimental part, we focus on classification tasks.

  18. 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

  19. Anatomic brain asymmetry in vervet monkeys.

    PubMed

    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.

  20. Cubesat Proximity Operations Demonstration (CPOD)

    NASA Technical Reports Server (NTRS)

    Villa, Marco; Martinez, Andres; Petro, Andrew

    2015-01-01

    The CubeSat Proximity Operations Demonstration (CPOD) project will demonstrate rendezvous, proximity operations and docking (RPOD) using two 3-unit (3U) CubeSats. Each CubeSat is a satellite with the dimensions 4 inches x 4 inches x 13 inches (10 centimeters x 10 centimeters x 33 centimeters) and weighing approximately 11 pounds (5 kilograms). This flight demonstration will validate and characterize many new miniature low-power proximity operations technologies applicable to future missions. This mission will advance the state of the art in nanosatellite attitude determination,navigation and control systems, in addition to demonstrating relative navigation capabilities.The two CPOD satellites are scheduled to be launched together to low-Earth orbit no earlier than Dec. 1, 2015.

  1. Asymmetry in zeta Auriage chromospheres

    NASA Technical Reports Server (NTRS)

    Ahmad, I. A.

    1988-01-01

    Asymmetry in the ultraviolet spectra of zeta-Aur, similar to that reported in optical observations, was studied using IUE data. A plot of the integrated flux of zeta Aurigae from 1625 to 1675 A as a function of absolute phase shows no significant difference between the ingress and egress phases. A plot of the integrated flux from 1625 to 1675 A for 22 Vul as a function of absolute phase for both ingress and egress confirms that the atmospheric eclipse is asymmetric in 22 Vul. The eclipse in 22 Vul begins symmetrically but departs from symmetry at a phase greater than 0.05. The pronounced dip at ingress suggests a feature in the chromosphere.

  2. 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).

  3. Asymmetry effects in fragment production

    SciTech Connect

    Kaur, Manpreet; Kaur, Varinderjit

    2016-05-06

    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 At{sub otal} 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 {sup 197}Au+{sup 27}Al (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).

  4. 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.

  5. Palatal asymmetry during development: an anatomical study.

    PubMed

    Moreira, R S; Sgrott, E A; Stuker, H; Alonso, L G; Smith, R L

    2008-07-01

    The purpose of this study was to evaluate hard palate asymmetry during development. The palates of 248 dry skulls were photographed and evaluated digitally. The skulls were divided into seven groups: fetus, newborn, infant, child, adolescent, adult, and aged. Linear measures were obtained from great palatine foramen (GPF) to incisive fossa (INC) and to posterior nasal spine (PNS). Angular measures were obtained from the former landmarks plus the point on sutures intersection between maxillary and palatine bones. Asymmetry was evaluated intra and intergroups. All skulls showed some degree of right-left asymmetry in the hard palate. Regardless of hard palate asymmetry, none of the right-left side differences was statistically significant. For the intergroups assessment, none of the asymmetry index means were statistically different. The posterior part of palate (PNS x GPF) measures was more asymmetric than the anterior part (INC x GPF), showing, respectively, 4.6% and 2.8% of mean asymmetry index. Angular measures showed a more symmetric behavior than the linear ones. Hard palate asymmetry occurs even in the absence of masticatory function, showing that this feature begins early in fetal life and persists through development.

  6. 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

  7. Abnormal asymmetry of brain connectivity in schizophrenia.

    PubMed

    Ribolsi, Michele; Daskalakis, Zafiris J; Siracusano, Alberto; Koch, Giacomo

    2014-01-01

    Recently, a growing body of data has revealed that beyond a dysfunction of connectivity among different brain areas in schizophrenia patients (SCZ), there is also an abnormal asymmetry of functional connectivity compared with healthy subjects. The loss of the cerebral torque and the abnormalities of gyrification, with an increased or more complex cortical folding in the right hemisphere may provide an anatomical basis for such aberrant connectivity in SCZ. Furthermore, diffusion tensor imaging studies have shown a significant reduction of leftward asymmetry in some key white-matter tracts in SCZ. In this paper, we review the studies that investigated both structural brain asymmetry and asymmetry of functional connectivity in healthy subjects and SCZ. From an analysis of the existing literature on this topic, we can hypothesize an overall generally attenuated asymmetry of functional connectivity in SCZ compared to healthy controls. Such attenuated asymmetry increases with the duration of the disease and correlates with psychotic symptoms. Finally, we hypothesize that structural deficits across the corpus callosum may contribute to the abnormal asymmetry of intra-hemispheric connectivity in schizophrenia.

  8. Proximity Sensors Make Robot Dexterous

    NASA Technical Reports Server (NTRS)

    Hess, Cliff; Li, Larry C. H.

    1990-01-01

    Control system enables robot hand to grasp objects of varied shapes. Key features of system: reflective proximity sensors furnishing data on position, orientation, and distance of object and software protocol controlling sequence of operations in approaching and grasping objects. Reflected-beam sensing concept applied to simple opposed-jaw industrial grippers as well as to dexterous robot hands.

  9. Driven shielding capacitive proximity sensor

    NASA Technical Reports Server (NTRS)

    Vranish, John M. (Inventor); McConnell, Robert L. (Inventor)

    2000-01-01

    A capacitive proximity sensing element, backed by a reflector driven at the same voltage as and in phase with the sensor, is used to reflect the field lines away from a grounded robot arm towards an intruding object, thus dramatically increasing the sensor's range and sensitivity.

  10. 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.

  11. 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.

  12. 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.

  13. SUSY CP phases and asymmetries at colliders

    NASA Astrophysics Data System (ADS)

    Kittel, Olaf

    2009-06-01

    In the Minimal Supersymmetric Standard Model, physical phases of complex parameters lead to CP violation. We show how triple products of particle momenta or spins can be used to construct asymmetries, that allow us to probe these CP phases. To give specific examples, we discuss the production of neutralinos at the International Linear Collider (ILC). For the Large Hadron Collider (LHC), we discuss CP asymmetries in squark decays, and in the tri-lepton signal. We find that the CP asymmetries can be as large as 60%.

  14. Proximity and Anti-proximity effects in nanowires

    NASA Astrophysics Data System (ADS)

    Chan, Moses

    Near a superconductor/normal-metal interface, the leakage of Cooper pairs extends superconducting behavior into the metal. The spatial range of this proximity effect in a normal metal can be as long as 1 µm. However, when a ferromagnet is placed in contact with a superconductor, the Cooper pairs from the superconductor are not expected to survive beyond at most a few nanometers into the ferromagnet. Surprisingly we find when a cobalt nanowire as long as 600 nm is sandwiched between superconducting electrodes, it attains zero resistance at low temperature. For even longer wires, the transition to incomplete superconductivity via this (long range) proximity effect is foreshadowed by a large resistance peak (1). On the other hand when Zn nanowires of 40 nm diameter are contacted by superconducting electrodes, their superconductivity is unexpectedly suppressed (2). Worked supported by Penn State MRSEC.

  15. Polarized view of the top asymmetry

    SciTech Connect

    Krohn, David; Liu Tao; Shelton, Jessie; Wang, Lian-Tao

    2011-10-01

    Recent experimental results from the CDF collaboration which study the top forward-backward asymmetry have strengthened the case that new physics is playing a role in tt production. Here, we propose a set of measurements, built from the charged lepton kinematics in semileptonic and fully leptonic tt events, designed to further probe the underlying causes of this asymmetry both at the Tevatron and at the LHC. Using a set of conservative reference models, we find that measurements of the charged lepton asymmetry, top polarization, and tt spin correlation can establish the existence of new physics and distinguish between competing models both at the Tevatron and the LHC. At the Tevatron, discrimination between models is possible at the 3{sigma} level. At the LHC, we demonstrate that a top forward-backward asymmetry can be established at > or approx. 3{sigma} in the first {approx}5 fb{sup -1} of data and show how competing explanations can be further disentangled.

  16. Detection of breast asymmetry using anatomical features

    NASA Astrophysics Data System (ADS)

    Miller, Peter; Astley, Susan M.

    1993-07-01

    We present a new approach to the detection of breast asymmetry, an important radiological sign of cancer. The conventional approach to this problem is to search for brightness or texture differences between corresponding locations on left and right breast images. Due to the difficulty in accurately identifying corresponding locations, asymmetry cues generated in this way are insufficiently specific to be used as prompts for small and subtle abnormalities in a computer-aided diagnosis system. We have undertaken studies to discover more about the visual cues utilized by radiologists. We propose a new automatic method for detecting asymmetry based on the comparison of corresponding anatomical structures, which are identified by an automatic segmentation of breast tissue types. We describe a number of methods for comparing the shape and grey-level distribution of these regions, and we have achieved promising results by combining evidence for asymmetry.

  17. 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.

  18. Leptogenesis and gravity: Baryon asymmetry without decays

    NASA Astrophysics Data System (ADS)

    McDonald, J. I.; Shore, G. M.

    2017-03-01

    A popular class of theories attributes the matter-antimatter asymmetry of the Universe to CP-violating decays of super-heavy BSM particles in the Early Universe. Recently, we discovered a new source of leptogenesis in these models, namely that the same Yukawa phases which provide the CP violation for decays, combined with curved-spacetime loop effects, lead to an entirely new gravitational mechanism for generating an asymmetry, driven by the expansion of the Universe and independent of the departure of the heavy particles from equilibrium. In this Letter, we build on previous work by analysing the full Boltzmann equation, exploring the full parameter space of the theory and studying the time-evolution of the asymmetry. Remarkably, we find regions of parameter space where decays play no part at all, and where the baryon asymmetry of the Universe is determined solely by gravitational effects.

  19. 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

  20. Optimal Branching Asymmetry of Hydrodynamic Pulsatile Trees

    NASA Astrophysics Data System (ADS)

    Florens, Magali; Sapoval, Bernard; Filoche, Marcel

    2011-04-01

    Most of the studies on optimal transport are done for steady state regime conditions. Yet, there exists numerous examples in living systems where supply tree networks have to deliver products in a limited time due to the pulsatile character of the flow, as it is the case for mammalian respiration. We report here that introducing a systematic branching asymmetry allows the tree to reduce the average delivery time of the products. It simultaneously increases its robustness against the inevitable variability of sizes related to morphogenesis. We then apply this approach to the human tracheobronchial tree. We show that in this case all extremities are supplied with fresh air, provided that the asymmetry is smaller than a critical threshold which happens to match the asymmetry measured in the human lung. This could indicate that the structure is tuned at the maximum asymmetry level that allows the lung to feed all terminal units with fresh air.

  1. Brain asymmetry: both sides of the story.

    PubMed

    Samara, Athina; Tsangaris, George T

    2011-12-01

    Biological systems demonstrate asymmetry, while lateralization has been observed from humans to lower animals structurally, functionally and behaviorally. This may be derived from evolutionary, genetic, developmental, epigenetic and pathologic factors. However, brain structure and function is complex, and macroscopic or microscopic asymmetries are hard to discern from random fluctuations. In this article, we discuss brain laterality and lateralization, beginning with a brief review of the literature on brain structural and functional asymmetries. We conclude with methods to detect and quantify asymmetry, focusing on neuroproteomics, for retrieval of protein-expression patterns, as a method of diagnosis and treatment monitoring. We suggest inter-hemispheric differential proteomics as a valid method to assess the experimental and biological variations in the healthy brain, and neurologic and neuropsychiatric disorders.

  2. Asymmetry in mechanical polarization switching

    NASA Astrophysics Data System (ADS)

    Lu, Haidong; Liu, Shi; Ye, Ziyu; Yasui, Shintaro; Funakubo, Hiroshi; Rappe, Andrew M.; Gruverman, Alexei

    2017-05-01

    Recent demonstration of a mechanical 180° switching of ferroelectric polarization has enabled an alternative polarization control mechanism based on the flexoelectric coupling between polarization and strain gradient. Mechanical switching is a highly asymmetric phenomenon associated with the inhomogeneous strain induced by an atomic force microscope (AFM) tip pressed against the ferroelectric surface. Here, we demonstrate the asymmetric domain switching behavior in the vicinity of the 180° domain wall in PbTiO3 thin films with respect to the AFM tip scanning direction. The writing-direction-dependent asymmetric domain response has been modeled by molecular dynamics simulation showing asymmetry in domain wall displacement due to the difference in the volume of mechanically switched domains. The obtained results show that the mechanically induced switching dynamics is very different from the conventional 180° switching realized by an external electric field and has to be exploited differently. In particular, nanoscale domain engineering via the tip-induced flexoelectric effect requires careful consideration of asymmetric interaction between the existing domain structures and the strain gradient.

  3. Actigraphic motor asymmetries during sleep.

    PubMed

    Violani, C; Testa, P; Casagrande, M

    1998-08-01

    Much evidence indicates that during sleep there is a repatterning of motor asymmetries with a relative advantage of the left hand (i.e., the left hand moves more than the right). This could be due to the ability of the right hemisphere in operating at levels of reduced arousal (arousal hypothesis) or to its superior spatial abilities (motor specificity hypothesis), or it could indicate a greater need for sleep in the left hemisphere (homeostatic hypothesis). Since only the latter hypothesis predicts that the repatterning should be present in the first part of sleep (i.e., when the homeostatic processes are more pronounced), the present study evaluated whether actigraphic data are consistent with this prediction. Sixteen right-handed college students wore actigraphs (AMI 16K) on both upper and lower limbs for about 56 hours. Factorial ANOVAS were carried out on side (left vs right) and part (first vs second) of the recording period during sleep and waking. During waking, the right hand showed more intense motor activity as compared to the left. During sleep, in the first part of the night, the right hand lost this advantage, while in the second part of the night it regained its superiority. Since this repatterning was specific for hand movements and no difference was found in overall motor activity and in arousal between the two parts of the sleep period, the results are interpreted as consistent with the homeostatic hypothesis.

  4. Forward-backward asymmetries of atomic photoelectrons.

    SciTech Connect

    Biheux, J. C.; Dunford, R. W.; Gemmell, D. S.; Hasegawa, S.; Kanter, E. P.; Krassig, B.; Southworth, S. H.; Young, L.

    1999-01-19

    When atomic photoionization is treated beyond the dipole approximation, photoelectron angular distributions are asymmetric forward and backward with respect to the direction of the photon beam. We have measured forward-backward asymmetries of Ar 1s and Kr 1s and 2s photoelectrons using 2-19 keV x-rays. The measured asymmetries compare well with calculations which include interference between electric-dipole and electric-quadrupole amplitudes within the nonrelativistic, independent-particle approximations.

  5. 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.

  6. 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

  7. 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.

  8. Asymmetries observed in Saturn's magnetopause geometry.

    PubMed

    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

    2015-09-16

    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°).

  9. 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°).

  10. Poloidal asymmetries in edge transport barriersa)

    NASA Astrophysics Data System (ADS)

    Churchill, R. M.; Theiler, C.; Lipschultz, B.; Hutchinson, I. H.; Reinke, M. L.; Whyte, D.; Hughes, J. W.; Catto, P.; Landreman, M.; Ernst, D.; Chang, C. S.; Hager, R.; Hubbard, A.; Ennever, P.; Walk, J. R.

    2015-05-01

    Measurements of impurities in Alcator C-Mod indicate that in the pedestal region, significant poloidal asymmetries can exist in the impurity density, ion temperature, and main ion density. In light of the observation that ion temperature and electrostatic potential are not constant on a flux surface [Theiler et al., Nucl. Fusion 54, 083017 (2014)], a technique based on total pressure conservation to align profiles measured at separate poloidal locations is presented and applied. Gyrokinetic neoclassical simulations with XGCa support the observed large poloidal variations in ion temperature and density, and that the total pressure is approximately constant on a flux surface. With the updated alignment technique, the observed in-out asymmetry in impurity density is reduced from previous publishing [Churchill et al., Nucl. Fusion 53, 122002 (2013)], but remains substantial ( n z , H / n z , L ˜ 6 ). Candidate asymmetry drivers are explored, showing that neither non-uniform impurity sources nor localized fluctuation-driven transport are able to explain satisfactorily the impurity density asymmetry. Since impurity density asymmetries are only present in plasmas with strong electron density gradients, and radial transport timescales become comparable to parallel transport timescales in the pedestal region, it is suggested that global transport effects relating to the strong electron density gradients in the pedestal are the main driver for the pedestal in-out impurity density asymmetry.

  11. Micropower RF material proximity sensor

    DOEpatents

    McEwan, Thomas E.

    1998-01-01

    A level detector or proximity detector for materials capable of sensing through plastic container walls or encapsulating materials is of the sensor. Thus, it can be used in corrosive environments, as well as in a wide variety of applications. An antenna has a characteristic impedance which depends on the materials in proximity to the antenna. An RF oscillator, which includes the antenna and is based on a single transistor in a Colpitt's configuration, produces an oscillating signal. A detector is coupled to the oscillator which signals changes in the oscillating signal caused by changes in the materials in proximity to the antenna. The oscillator is turned on and off at a pulse repetition frequency with a low duty cycle to conserve power. The antenna consists of a straight monopole about one-quarter wavelength long at the nominal frequency of the oscillator. The antenna may be horizontally disposed on a container and very accurately detects the fill level within the container as the material inside the container reaches the level of the antenna.

  12. Proximity lithography membrane mask aeroelasticity

    NASA Astrophysics Data System (ADS)

    Huston, Dryver; Burns, Dylan; Boerger, Brent; Selzer, Robert

    2006-03-01

    Proximity lithography places a thin membrane mask into close proximity (5-100 micron) to a wafer for exposure to radiation and pattern placement. Efficient production practices require that the wafer be positioned relative to the mask as quickly as possible. The positioning maneuvers involve both a lateral motion and a closing of the mask-to-wafer gap. Gap closing requires forcing the exposure chamber gas (usually air or helium, possibly at a mild vacuum) between the mask and wafer out through the edges of the gap in a squeeze film process that can substantially deflect and damage the membrane mask. Moving laterally, i.e. stepping, would be more efficient if it were performed at the close proximity gap. The buildup of hydrodynamic pressures while stepping at gap can deform and possibly damage the mask. This paper discusses methods to model, measure and control aeroelastic effects due to gap closing and lateral stepping at gap. The analysis considers an aeroelastic model based on coupling Reynolds' hydrodynamic lubrication theory with membrane mechanics. A principal result of the analysis is the prediction that it is possible to step at gap and produce minimal aeroelastic out-of-plane deflections, if the wedge angle is zero, and both the membrane and mask have a flat profile. The aeroelastic models are confirmed with experiments that measure out-of-plane stepping of a membrane versus wedge angle, gap and speed. Non-flat mask profiles, such as buttes and mesas raise additional aeroelastic issues are also examined.

  13. Micropower RF material proximity sensor

    DOEpatents

    McEwan, T.E.

    1998-11-10

    A level detector or proximity detector for materials capable of sensing through plastic container walls or encapsulating materials is disclosed. Thus, it can be used in corrosive environments, as well as in a wide variety of applications. An antenna has a characteristic impedance which depends on the materials in proximity to the antenna. An RF oscillator, which includes the antenna and is based on a single transistor in a Colpitt`s configuration, produces an oscillating signal. A detector is coupled to the oscillator which signals changes in the oscillating signal caused by changes in the materials in proximity to the antenna. The oscillator is turned on and off at a pulse repetition frequency with a low duty cycle to conserve power. The antenna consists of a straight monopole about one-quarter wavelength long at the nominal frequency of the oscillator. The antenna may be horizontally disposed on a container and very accurately detects the fill level within the container as the material inside the container reaches the level of the antenna. 5 figs.

  14. [Proximal and total femur replacement].

    PubMed

    Pennekamp, P H; Wirtz, D C; Dürr, H R

    2012-07-01

    Reconstruction of segmental bone defects of the proximal femur following wide tumor resection or revision arthroplasty. Aggressive benign or primary malignant bone tumors of the proximal femur; destructive metastases; massive segmental bone defects of the proximal femur; periprosthetic fractures. Local infection; very short life expectancy (< 3 months); massive deficiency of acetabular bone stock. Anterolateral approach. Exposure and detachment of the iliopsoas and gluteus medius muscle from the proximal femur with a sufficient safety margin to the bone; distal transsection of the vastus lateralis/intermedius and rectus femoris muscle according to the extraosseous tumor extension; distal femur osteotomy al least 3 cm beyond the farthest point of tumor extension; in case of total femur replacement, additional lateral arthrotomy of the knee with resection of the ligaments and menisci; reaming of the medullary canal after securing the shaft with a Verbrugge clamp; trial assembly and reduction followed by the definitive implantation of the prosthesis with adjustment of the femoral neck anteversion in 5° increments; soft tissue reconstruction and fixation to an attachment tube covering the prosthesis; in case of total femur replacement, the preparation of the tibia is followed by the coupling of the tibial and femoral components. Infection prophylaxis, 20 kg partial weight bearing, continuous passive motion. A total of 20  patients with proximal femur replacement and 2 patients with total femur replacement implanted between June 2007 and December 2011 were retrospectively reviewed. Three patients had primary malignant bone tumors, while 19 patients underwent resection for metastatic disease. The mean age at surgery was 62.0 ± 18.1 years (18-82 years). Fifteen patients with a mean follow-up of 20.3 ± 17.2 months (4-51 months) were studied. Among the 22 cases, periprosthetic infection occurred in 3 patients (13.6%), dislocation in 2 patients (9

  15. Proximate and polyphenolic characterization of cranberry pomace

    USDA-ARS?s Scientific Manuscript database

    The proximate composition and identification and quantification of polyphenolic compounds in dried cranberry pomace were determined. Proximate analysis was conducted based on AOAC methods for moisture, protein, fat, and ash. Total carbohydrates were determined by the difference method. Polyphenolic ...

  16. Active Targets For Capacitive Proximity Sensors

    NASA Technical Reports Server (NTRS)

    Jenstrom, Del T.; Mcconnell, Robert L.

    1994-01-01

    Lightweight, low-power active targets devised for use with improved capacitive proximity sensors described in "Capacitive Proximity Sensor Has Longer Range" (GSC-13377), and "Capacitive Proximity Sensors With Additional Driven Shields" (GSC-13475). Active targets are short-distance electrostatic beacons; they generate known alternating electro-static fields used for alignment and/or to measure distances.

  17. Cerebellar asymmetry and its relation to cerebral asymmetry estimated by intrinsic functional connectivity

    PubMed Central

    Wang, Danhong; Buckner, Randy L.

    2013-01-01

    Asymmetry of the human cerebellum was investigated using intrinsic functional connectivity. Regions of functional asymmetry within the cerebellum were identified during resting-state functional MRI (n = 500 subjects) and replicated in an independent cohort (n = 500 subjects). The most strongly right lateralized cerebellar regions fell within the posterior lobe, including crus I and crus II, in regions estimated to link to the cerebral association cortex. The most strongly left lateralized cerebellar regions were located in lobules VI and VIII in regions linked to distinct cerebral association networks. Comparison of cerebellar asymmetry with independently estimated cerebral asymmetry revealed that the lateralized regions of the cerebellum belong to the same networks that are strongly lateralized in the cerebrum. The degree of functional asymmetry of the cerebellum across individuals was significantly correlated with cerebral asymmetry and varied with handedness. In addition, cerebellar asymmetry estimated at rest predicted cerebral lateralization during an active language task. These results demonstrate that functional lateralization is likely a unitary feature of large-scale cerebrocerebellar networks, consistent with the hypothesis that the cerebellum possesses a roughly homotopic map of the cerebral cortex including the prominent asymmetries of the association cortex. PMID:23076113

  18. Movement asymmetry in working polo horses.

    PubMed

    Pfau, T; Parkes, R S; Burden, E R; Bell, N; Fairhurst, H; Witte, T H

    2016-07-01

    The high, repetitive demands imposed on polo horses in training and competition may predispose them to musculoskeletal injuries and lameness. To quantify movement symmetry and lameness in a population of polo horses, and to investigate the existence of a relationship with age. Convenience sampled cross-sectional study. Sixty polo horses were equipped with inertial measurement units (IMUs) attached to the poll, and between the tubera sacrale. Six movement symmetry measures were calculated for vertical head and pelvic displacement during in-hand trot and compared with values for perfect symmetry, compared between left and right limb lame horses, and compared with published thresholds for lameness. Regression lines were calculated as a function of age of horse. Based on 2 different sets of published asymmetry thresholds 52-53% of the horses were quantified with head movement asymmetry and 27-50% with pelvic movement asymmetry resulting in 60-67% of horses being classified with movement asymmetry outside published guideline values for either the forelimbs, hindlimbs or both. Neither forelimb nor hindlimb asymmetries were preferentially left or right sided, with directional asymmetry values across all horses not different from perfect symmetry and absolute values not different between left and right lame horses (P values >0.6 for all forelimb symmetry measures and >0.2 for all hindlimb symmetry measures). None of the symmetry parameters increased or decreased significantly with age. A large proportion of polo horses show gait asymmetries consistent with previously defined thresholds for lameness. These do not appear to be lateralised or associated with age. © 2015 EVJ Ltd.

  19. The HTV Proximity Communication System

    NASA Astrophysics Data System (ADS)

    Harada, Motoyuki; Takahashi, Tetsuo; Tanaka, Tetsuo

    2002-01-01

    National Space Development Agency of Japan (NASDA) is developing the H-II Transfer Vehicle (HTV) as an unmanned logistic support vehicle for the International Space Station (ISS). The HTV, which is launched by the H-IIA rocket, transports both pressurized and un-pressurized cargoes to the ISS, reloads disposal items from the ISS and performs destructive reentry over ocean area. NASDA plans the first flight of HTV in 2005 for demonstration. The HTV will contribute the ISS assembly and logistic re-supply operations with international commonality. For unmanned vehicle operation, communication link is critical with commanding and control, especially in proximity region to the ISS. As for the HTV operation, NASDA is developing dedicated communication system installed on the Japanese Experiment Module (JEM) of the ISS, which is called the Proximity Communication System (PROX). The HTV receives commands and transmits telemetry data through the PROX in its proximity operation to the ISS. To achieve this, the PROX can communicate with the HTV on its nominal trajectory within 23km of the ISS. Especially within 3km of the ISS, the PROX has capability to perform omni-directional communication to the HTV. The PROX also has GPS receiver and send GPS data to the HTV to support the HTV navigation for relative GPS navigation used in "far" range (500m away from the ISS). In addition to the above fundamental functions, the PROX has a capability of range and range-rate measurement between the ISS and the HTV by the pseudo noise (PN) code epoch and the Doppler shift frequency. This provides a reference data independent of "main" navigation methods (rendezvous sensor navigation or GPS navigation) of the HTV. The PROX also assists the ISS crew with its commanding device, called the Hardware Command Panel (HCP), to issue time-dependent safety-related critical commands for HTV berthing/un-berthing operation. When a failure occurs somewhere on "communication path" from the PROX Base Band

  20. Proximal Biceps in Overhead Athletes.

    PubMed

    Chalmers, Peter N; Verma, Nikhil N

    2016-01-01

    The proximal long head of the biceps tendon and its attachment at the superior glenoid tubercle and labrum are subject to a spectrum of disorders in overhead athletes. Biceps disorders are commonly characterized by intermittent anterior or deep-seated shoulder pain exacerbated by activity. Diagnosis is reached via various physical examination maneuvers; MRI can be uncertain. Nonsteroidal anti-inflammatory medications, targeted ultrasound-guided corticosteroid injections, and supervised physical therapy are the mainstays of nonoperative treatment. Operative treatment, which remains controversial, provides reliable pain relief, restoration of function for activities of daily living, and low complication rates, but return to play can be unpredictable.

  1. Analytical formulation of lunar cratering asymmetries

    NASA Astrophysics Data System (ADS)

    Wang, Nan; Zhou, Ji-Lin

    2016-10-01

    Context. The cratering asymmetry of a bombarded satellite is related to both its orbit and impactors. The inner solar system impactor populations, that is, the main-belt asteroids (MBAs) and the near-Earth objects (NEOs), have dominated during the late heavy bombardment (LHB) and ever since, respectively. Aims: We formulate the lunar cratering distribution and verify the cratering asymmetries generated by the MBAs as well as the NEOs. Methods: Based on a planar model that excludes the terrestrial and lunar gravitations on the impactors and assuming the impactor encounter speed with Earth venc is higher than the lunar orbital speed vM, we rigorously integrated the lunar cratering distribution, and derived its approximation to the first order of vM/venc. Numerical simulations of lunar bombardment by the MBAs during the LHB were performed with an Earth-Moon distance aM = 20-60 Earth radii in five cases. Results: The analytical model directly proves the existence of a leading/trailing asymmetry and the absence of near/far asymmetry. The approximate form of the leading/trailing asymmetry is (1 + A1cosβ), which decreases as the apex distance β increases. The numerical simulations show evidence of a pole/equator asymmetry as well as the leading/trailing asymmetry, and the former is empirically described as (1 + A2cos2ϕ), which decreases as the latitude modulus | ϕ | increases. The amplitudes A1,2 are reliable measurements of asymmetries. Our analysis explicitly indicates the quantitative relations between cratering distribution and bombardment conditions (impactor properties and the lunar orbital status) like A1 ∝ vM/venc, resulting in a method for reproducing the bombardment conditions through measuring the asymmetry. Mutual confirmation between analytical model and numerical simulations is found in terms of the cratering distribution and its variation with aM. Estimates of A1 for crater density distributions generated by the MBAs and the NEOs are 0.101-0.159 and 0

  2. The Inherent Asymmetry of DNA Replication.

    PubMed

    Snedeker, Jonathan; Wooten, Matthew; Chen, Xin

    2017-08-11

    Semiconservative DNA replication has provided an elegant solution to the fundamental problem of how life is able to proliferate in a way that allows cells, organisms, and populations to survive and replicate many times over. Somewhat lost, however, in our admiration for this elegant mechanism is an appreciation for the asymmetries that occur in the process of DNA replication. As we discuss in this review, these asymmetries arise as a consequence of the structure of the DNA molecule and the enzymatic mechanism of DNA synthesis. Increasing evidence suggests that asymmetries inDNAreplication are able to play a central role in the processes of adaptation and evolution by shaping the mutagenic landscape of cells. Additionally, in eukaryotes, recent work has demonstrated that the inherent asymmetries in DNA replication may play an important role in the process of chromatin replication. As chromatin plays an essential role in defining cell identity, asymmetries generated during the process of DNA replication may play critical roles in cell fate dicisions related to patterning and development. Expected final online publication date for the Annual Review of Cell and Developmental Biology Volume 33 is October 6, 2017. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

  3. Quantum asymmetry between time and space.

    PubMed

    Vaccaro, Joan A

    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.

  4. Hemispheric asymmetries in cortical and subcortical anatomy.

    PubMed

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

    2015-01-01

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

  5. 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

  6. Predicting combinations of left and right asymmetries.

    PubMed

    Annett, M

    2000-09-01

    This paper explains how combinations of asymmetries for pairs of laterality variables may be predicted. It shows that many pairs combine as expected by chance, plus the influence of the RS+ gene hypothesised by Annett (1978, 1985). These include: eye dominance with writing hand, with throwing hand, and with foot for kicking; nonright handedness with planum temporale asymmetry, with asymmetry of the parietal operculum, and the association between these two anatomical asymmetries. Handedness for writing and throwing, and hand and foot preferences are more strongly associated, suggesting the presence of an additional influence. The reliability of the present analyses was supported by replication, especially in findings for hand preferences for writing and throwing described by Gilbert and Wysocki (1992). The relative frequencies of discordant patterns of preference, LR (writing, throwing) versus RL, are a function of the frequencies of the two variables in the population. These differ between age groups and also with the classification of 'either' hand preferences. Patterns of preference for writing, throwing and eye-dominance (RRR, RRL etc) are related in an orderly manner to differences between the hands for peg moving time. The success of the present application of the RS theory strengthens the argument that individual differences for hand preference depend on a continuous distribution of asymmetry, not on the 'types' commonly assumed in the literature.

  7. Corrections to quark asymmetries at LEP

    SciTech Connect

    Freitas, A.; Monig, K.; /DESY, Zeuthen

    2004-11-01

    The most precise measurement of the weak mixing angle sin{sup 2} {theta}{sub eff}{sup l} at LEP is from the forward-backward asymmetry e{sup +}e{sup -} {yields} b{bar b} at the Z-pole. In this note the QED and electroweak radiative corrections to obtain the pole asymmetry from the measured asymmetry for b- and c-quarks have been calculated using ZFITTER, which has been amended to allow a consistent treatment of partial two-loop corrections for the b-quark final asymmetries. A total correction of {delta}A{sub FB}{sup b} = 0.0019 {+-} 0.0002 and {delta}A{sub FB}{sup c} = 0.0064 {+-} 0.0001 has been found, where the remaining theoretical uncertainty is much too small to explain the apparent discrepancy between sin{sup 2} {theta}{sub eff}{sup l} obtained from A{sub FB}{sup b} and from the left-right asymmetry at SLD.

  8. 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.

  9. 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.

  10. Fibrosis: ultimate and proximate causes

    PubMed Central

    Thannickal, Victor J.; Zhou, Yong; Gaggar, Amit; Duncan, Steven R.

    2014-01-01

    Fibrotic disorders account for an increasing burden of disease-associated morbidity and mortality worldwide. Although numerous risk factors have been recognized, the etiologies of many of these clinical syndromes have not been identified, and they are often termed idiopathic or cryptogenic. Here, we provide an evolutionary perspective on fibrosis aimed at elucidating its etiopathogenesis. By asking the ultimate question of “why” this process evolved in multicellular organisms, we hope to uncover proximate explanations for “how” it causes disease in humans. We posit that physiological fibrosis-like reactions evolved as an essential process in host defense against pathogens and in normal wound healing. Based on this premise, we reason that pathological fibrosis is related to one or more of the following: unidentified infectious or noninfectious antigens, autoimmunity, impaired regenerative responses, and the antagonistically pleiotropic action of genes involved in wound healing or development. The importance of genetic susceptibility, epigenetics, aging, and the modern-day environment are highlighted. Consideration of both ultimate and proximate causation goes beyond philosophical cogitations, as it will better inform pathobiological mechanisms of disease and aid in the prevention and treatment of fibrotic diseases. PMID:25365073

  11. Chemokines in tumor proximal fluids.

    PubMed

    Kotyza, Jaromir

    2017-03-01

    Chemokines are chemotactic cytokines produced by leukocytes and other types of cells including tumor cells. Their action is determined by the expression of cognate receptors and subsequent signaling in target cells, followed by the modulation of cytoskeletal proteins and the induction of other responses. In tumors, chemokines produced by neoplastic/stroma cells control the leukocyte infiltrate influencing tumor growth and progression. Tumor cells also express functional chemokine receptors responding to chemokine signals, promoting cell survival, proliferation and metastasis formation. Chemokines may be detected in serum of cancer patients, but due to the paracrine nature of these molecules, more significant concentrations are found in the tumor adjacent, non-vascular fluids, collectively called tumor proximal fluids. This review summarizes the expression of CC and CXC chemokines in these fluids, namely in interstitial fluid, pleural, ascitic, and cyst fluids, but also in urine, saliva, cerebrospinal fluid, cervical secretions and bronchoalveolar lavage fluid. Most comparative clinical studies reveal increased chemokine levels in high-grade tumor proximal fluids rather than in low-grade tumors and benign conditions, indicating shorter survival periods. The data confirm peritumoral fluid chemokines as sensitive diagnostic and prognostic markers, as well as offer support for chemokines and their receptors as potential targets for antitumor therapy.

  12. Proximal bodies in hypersonic flow

    SciTech Connect

    Deiterding, Ralf; Laurence, Stuart J; Hornung, Hans G

    2007-01-01

    Hypersonic flows involving two or more bodies travelling in close proximity to one another are encountered in several important situations, both natural and man-made. The present work seeks to investigate one aspect of the resulting flow problem by exploring the forces experienced by a secondary body when it is within the domain of influence of a primary body travelling at hypersonic speeds. An analytical methodology based on the blast wave analogy is developed and used to predict the secondary force coefficients for simple geometries in both two and three dimensions. When the secondary body is entirely inside the primary shocked region, the nature of the lateral force coefficient is found to depend strongly on the relative size of the two bodies. For two spheres, the methodology predicts that the secondary body will experience an exclusively attractive lateral force if the secondary diameter is larger than one-sixth the primary diameter. The analytical results are compared with those from numerical simulations and reasonable agreement is observed if an appropriate normalization for the lateral displacement is used. Results from a series of experiments in the T5 hypervelocity shock tunnel are also presented and compared with perfect-gas numerical simulations, with good agreement. A new force-measurement technique for short-duration hypersonic facilities, enabling the experimental simulation of the proximal bodies problem, is described. This technique provides two independent means of measurement, and the agreement observed between the two gives a further degree of confidence in the results obtained.

  13. Protein Neighbors and Proximity Proteomics*

    PubMed Central

    Rees, Johanna S.; Li, Xue-Wen; Perrett, Sarah; Lilley, Kathryn S.; Jackson, Antony P.

    2015-01-01

    Within cells, proteins can co-assemble into functionally integrated and spatially restricted multicomponent complexes. Often, the affinities between individual proteins are relatively weak, and proteins within such clusters may interact only indirectly with many of their other protein neighbors. This makes proteomic characterization difficult using methods such as immunoprecipitation or cross-linking. Recently, several groups have described the use of enzyme-catalyzed proximity labeling reagents that covalently tag the neighbors of a targeted protein with a small molecule such as fluorescein or biotin. The modified proteins can then be isolated by standard pulldown methods and identified by mass spectrometry. Here we will describe the techniques as well as their similarities and differences. We discuss their applications both to study protein assemblies and to provide a new way for characterizing organelle proteomes. We stress the importance of proteomic quantitation and independent target validation in such experiments. Furthermore, we suggest that there are biophysical and cell-biological principles that dictate the appropriateness of enzyme-catalyzed proximity labeling methods to address particular biological questions of interest. PMID:26355100

  14. Protein Neighbors and Proximity Proteomics.

    PubMed

    Rees, Johanna S; Li, Xue-Wen; Perrett, Sarah; Lilley, Kathryn S; Jackson, Antony P

    2015-11-01

    Within cells, proteins can co-assemble into functionally integrated and spatially restricted multicomponent complexes. Often, the affinities between individual proteins are relatively weak, and proteins within such clusters may interact only indirectly with many of their other protein neighbors. This makes proteomic characterization difficult using methods such as immunoprecipitation or cross-linking. Recently, several groups have described the use of enzyme-catalyzed proximity labeling reagents that covalently tag the neighbors of a targeted protein with a small molecule such as fluorescein or biotin. The modified proteins can then be isolated by standard pulldown methods and identified by mass spectrometry. Here we will describe the techniques as well as their similarities and differences. We discuss their applications both to study protein assemblies and to provide a new way for characterizing organelle proteomes. We stress the importance of proteomic quantitation and independent target validation in such experiments. Furthermore, we suggest that there are biophysical and cell-biological principles that dictate the appropriateness of enzyme-catalyzed proximity labeling methods to address particular biological questions of interest.

  15. Ash Aggregates in Proximal Settings

    NASA Astrophysics Data System (ADS)

    Porritt, L. A.; Russell, K.

    2012-12-01

    Ash aggregates are thought to have formed within and been deposited by the eruption column and plume and dilute density currents and their associated ash clouds. Moist, turbulent ash clouds are considered critical to ash aggregate formation by facilitating both collision and adhesion of particles. Consequently, they are most commonly found in distal deposits. Proximal deposits containing ash aggregates are less commonly observed but do occur. Here we describe two occurrences of vent proximal ash aggregate-rich deposits; the first within a kimberlite pipe where coated ash pellets and accretionary lapilli are found within the intra-vent sequence; and the second in a glaciovolcanic setting where cored pellets (armoured lapilli) occur within <1 km of the vent. The deposits within the A418 pipe, Diavik Diamond Mine, Canada, are the residual deposits within the conduit and vent of the volcano and are characterised by an abundance of ash aggregates. Coated ash pellets are dominant but are followed in abundance by ash pellets, accretionary lapilli and rare cored pellets. The coated ash pellets typically range from 1 - 5 mm in diameter and have core to rim ratios of approximately 10:1. The formation and preservation of these aggregates elucidates the style and nature of the explosive phase of kimberlite eruption at A418 (and other pipes?). First, these pyroclasts dictate the intensity of the kimberlite eruption; it must be energetic enough to cause intense fragmentation of the kimberlite to produce a substantial volume of very fine ash (<62 μm). Secondly, the ash aggregates indicate the involvement of moisture coupled with the presence of dilute expanded eruption clouds. The structure and distribution of these deposits throughout the kimberlite conduit demand that aggregation and deposition operate entirely within the confines of the vent; this indicates that aggregation is a rapid process. Ash aggregates within glaciovolcanic sequences are also rarely documented. The

  16. 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.

  17. Superheavy thermal dark matter and primordial asymmetries

    NASA Astrophysics Data System (ADS)

    Bramante, Joseph; Unwin, James

    2017-02-01

    The early universe could feature multiple reheating events, leading to jumps in the visible sector entropy density that dilute both particle asymmetries and the number density of frozen-out states. In fact, late time entropy jumps are usually required in models of Affleck-Dine baryogenesis, which typically produces an initial particle-antiparticle asymmetry that is much too large. An important consequence of late time dilution, is that a smaller dark matter annihilation cross section is needed to obtain the observed dark matter relic density. For cosmologies with high scale baryogenesis, followed by radiation-dominated dark matter freeze-out, we show that the perturbative unitarity mass bound on thermal relic dark matter is relaxed to 1010 GeV. We proceed to study superheavy asym-metric dark matter models, made possible by a sizable entropy injection after dark matter freeze-out, and identify how the Affleck-Dine mechanism would generate the baryon and dark asymmetries.

  18. Preliminary Proton Spin Asymmetry Results from SANE

    NASA Astrophysics Data System (ADS)

    Maxwell, James

    2010-11-01

    The Spin Asymetries of the Nucleon Experiment (SANE) is a measurement of parallel and near-perpendicular double spin asymmetries in an inclusive electron scattering experiment, with the aim of calculating the spin asymmetry of the proton A^1p and spin structure function g^2p. Using Thomas Jefferson National Accelerator Facility's polarized electron beam and the University of Virginia's polarized frozen ammonia (^14NH3) target in Hall C, the experiment ran in 2009, collecting data in a Q^2 region from 2.5 to 6.5 GeV^2 in a Bjorken x region of 0.3 to 0.8. Particle detection was accomplished using the Big Electron Telescope Array (BETA), a novel non-magnetic detector array with a 194 msr acceptance. This talk will address the progress of the analysis toward the calculation of the proton spin asymmetry and structure functions, including calibration of the BETA detectors, event selection, and preliminary results.

  19. CP asymmetries in semiinclusive B0 decays

    SciTech Connect

    Dunietz, I.

    1999-02-01

    It was recently pointed out that inclusive B^0(t) decays could show CP violation. The totally inclusive asymmetry is expected to be tiny [O(10^{-3})] because of large cancellations among the asymmetries in the charmless, single charm and double charm final states. Enriching particular final state configurations could significantly increase the CP-asymmetry and observability. Such studies can extract fundamental CKM (Cabibbo-Kobayashi-Maskawa) parameters, and (perhaps) even Delta m(B_s). A superb vertex detector could see CP violation with 10^5 (10^6) flavor-tagged B_s (B_d) mesons within the CKM model. Because the effects could be significantly larger due to new physics, they should be searched for in existing or soon available data samples.

  20. Gain loss asymmetry for emerging stock markets

    NASA Astrophysics Data System (ADS)

    Karpio, Krzysztof; Załuska–Kotur, Magdalena A.; Orłowski, Arkadiusz

    2007-03-01

    Stock indexes for some European emerging markets are analyzed using an investment-horizon approach. Austrian ATX index and Dow Jones have been studied and compared with several emerging European markets. The optimal investment horizons are plotted as a function of an absolute return value. Gain-loss asymmetry, originally found for American DJIA index, is observed for all analyzed data. It is shown, that this asymmetry has different character for emerging and for established markets. For established markets, gain curve lies typically above loss curve, whereas in the case of emerging markets the situation is just the opposite. We propose a measure quantifying the gain-loss asymmetry that clearly exhibits a difference between emerging and established markets.

  1. Effect of stress on structural brain asymmetry.

    PubMed

    Zach, Petr; Vales, Karel; Stuchlik, Ales; Cermakova, Pavla; Mrzilkova, Jana; Koutela, Antonella; Kutova, Martina

    2016-09-01

    There is a growing body of evidence that stressful events may affect the brain not only as a whole, but also in multiple laterality aspects. The present review is aimed at discussing the effect of stress and stress hormones on structural brain asymmetry. Differences and crossroads of functional and structural asymmetry are briefly mentioned throughout the document. The first part of this review summarizes major findings in the field of structural brain asymmetries in animals and humans from the evolutionary perspective. Additionally, effect of stress on animals is discussed generally. The second part then explores asymmetrical effects of stress on structural changes of principal brain areas - amygdala, hippocampus, neocortex, diencephalon, basal forebrain and basal ganglia from the point of normal lateralization, steroids, trauma and genetic factors. At the end we present hypothesis why stress appears to have asymmetrical effects on lateralized brain structures.

  2. Frontal alpha asymmetry and sexually motivated states.

    PubMed

    Prause, Nicole; Staley, Cameron; Roberts, Verena

    2014-03-01

    Anterior alpha asymmetry of electroencephalographic (EEG) signals has been suggested to index state approach (or avoidance) motivation. This model has not yet been extended to high approach-motivation sexual stimuli, which may represent an important model of reward system function. Sixty-five participants viewed a neutral and a sexually motivating film while their EEG was recorded, and reported their sexual feelings after each film. Greater alpha power in the left hemisphere during sexually motivated states was evident. A positive relationship between self-reported mental sexual arousal and alpha asymmetry was identified, where coherence between these indicators was higher in women. Notably, coherence was stronger when mental versus physical sexual arousal was rated. Alpha asymmetry appears to offer a new method for further examining this novel coherence pattern across men and women.

  3. Asymmetry dependence of the nuclear caloric curve

    NASA Astrophysics Data System (ADS)

    McIntosh, A. B.; Bonasera, A.; Cammarata, P.; Hagel, K.; Heilborn, L.; Kohley, Z.; Mabiala, J.; May, L. W.; Marini, P.; Raphelt, A.; Souliotis, G. A.; Wuenschel, S.; Zarrella, A.; Yennello, S. J.

    2013-02-01

    A basic feature of the nuclear equation of state is not yet understood: the dependence of the nuclear caloric curve on the neutron-proton asymmetry. Predictions of theoretical models differ on the magnitude and even the sign of this dependence. In this work, the nuclear caloric curve is examined for fully reconstructed quasi-projectiles around mass A = 50. The caloric curve extracted with the momentum quadrupole fluctuation thermometer shows that the temperature varies linearly with quasi-projectile asymmetry N-Z/A. An increase in asymmetry of 0.15 units corresponds to a decrease in temperature on the order of 1 MeV. These results also highlight the importance of a full quasi-projectile reconstruction in the study of thermodynamic properties of hot nuclei.

  4. Asymmetry Dependence of the Nuclear Caloric Curve

    NASA Astrophysics Data System (ADS)

    McIntosh, A. B.; Bonasera, A.; Cammarata, P.; Hagel, K.; Heilborn, L.; Kohley, Z.; Mabiala, J.; May, L. W.; Marini, P.; Raphelt, A.; Souliotis, G. A.; Wuenschel, S.; Zarrella, A.; Yennello, S. J.

    2013-03-01

    A basic feature of the nuclear equation of state is not yet understood: the dependence of the nuclear caloric curve on the neutron-proton asymmetry. Predictions of theoretical models differ on the magnitude and even the sign of this dependence. In this work, the nuclear caloric curve is examined for fully reconstructed quasi-projectiles around mass A = 50. Two independent thermometers, the momentum quadrupole fluctuation thermometer and the Albergo yield ratio thermometer, are used to extract the caloric curve. For both methods, the caloric curve extracted shows that the temperature varies linearly with quasi-projectile asymmetry For the momentum quadrupole fluctuation thermometer, an increase in asymmetry of 0.15 units corresponds to a decrease in temperature on the order of 1 MeV. These results also highlight the importance of a full quasi-projectile reconstruction in the study of thermodynamic properties of hot nuclei.

  5. 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

  6. Footwear Decreases Gait Asymmetry during Running.

    PubMed

    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.

  7. Asymmetry of planum temporale constrains interhemispheric language plasticity in children with focal epilepsy

    PubMed Central

    Pahs, Gerald; Rankin, Peter; Helen Cross, J.; Croft, Louise; Northam, Gemma B.; Liegeois, Frederique; Greenway, Sarah; Harrison, Sue; Vargha-Khadem, Faraneh

    2013-01-01

    Reorganization of eloquent cortex enables rescue of language functions in patients who sustain brain injury. Individuals with left-sided, early-onset focal epilepsy often show atypical (i.e. bilateral or right-sided) language dominance. Surprisingly, many patients fail to show such interhemispheric shift of language despite having major epileptogenic lesions in close proximity to eloquent cortex. Although a number of epilepsy-related factors may promote interhemispheric plasticity, it has remained unexplored if neuroanatomical asymmetries linked to human language dominance modify the likelihood of atypical lateralization. Here we examined the asymmetry of the planum temporale, one of the most striking asymmetries in the human brain, in relation to language lateralization in children with left-sided focal epilepsy. Language functional magnetic resonance imaging was performed in 51 children with focal epilepsy and left-sided lesions and 36 healthy control subjects. We examined the association of language laterality with a range of potential clinical predictors and the asymmetry of the length of the planum temporale. Using voxel-based methods, we sought to determine the effect of lesion location (in the affected left hemisphere) and grey matter density (in the unaffected right hemisphere) on language laterality. Atypical language lateralization was observed in 19 patients (38%) and in four controls (11%). Language laterality was increasingly right-sided in patients who showed atypical handedness, a left perisylvian ictal electroencephalographic focus, and a lesion in left anterior superior temporal or inferior frontal regions. Most striking was the relationship between rightward asymmetry of the planum temporale and atypical language (R = 0.70, P < 0.0001); patients with a longer planum temporale in the right (unaffected) hemisphere were more likely to have atypical language dominance. Voxel-based regression analysis confirmed that increased grey matter density in the

  8. Asymmetry of planum temporale constrains interhemispheric language plasticity in children with focal epilepsy.

    PubMed

    Pahs, Gerald; Rankin, Peter; Helen Cross, J; Croft, Louise; Northam, Gemma B; Liegeois, Frederique; Greenway, Sarah; Harrison, Sue; Vargha-Khadem, Faraneh; Baldeweg, Torsten

    2013-10-01

    Reorganization of eloquent cortex enables rescue of language functions in patients who sustain brain injury. Individuals with left-sided, early-onset focal epilepsy often show atypical (i.e. bilateral or right-sided) language dominance. Surprisingly, many patients fail to show such interhemispheric shift of language despite having major epileptogenic lesions in close proximity to eloquent cortex. Although a number of epilepsy-related factors may promote interhemispheric plasticity, it has remained unexplored if neuroanatomical asymmetries linked to human language dominance modify the likelihood of atypical lateralization. Here we examined the asymmetry of the planum temporale, one of the most striking asymmetries in the human brain, in relation to language lateralization in children with left-sided focal epilepsy. Language functional magnetic resonance imaging was performed in 51 children with focal epilepsy and left-sided lesions and 36 healthy control subjects. We examined the association of language laterality with a range of potential clinical predictors and the asymmetry of the length of the planum temporale. Using voxel-based methods, we sought to determine the effect of lesion location (in the affected left hemisphere) and grey matter density (in the unaffected right hemisphere) on language laterality. Atypical language lateralization was observed in 19 patients (38%) and in four controls (11%). Language laterality was increasingly right-sided in patients who showed atypical handedness, a left perisylvian ictal electroencephalographic focus, and a lesion in left anterior superior temporal or inferior frontal regions. Most striking was the relationship between rightward asymmetry of the planum temporale and atypical language (R = 0.70, P < 0.0001); patients with a longer planum temporale in the right (unaffected) hemisphere were more likely to have atypical language dominance. Voxel-based regression analysis confirmed that increased grey matter density in the

  9. 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.

  10. Neutron single target spin asymmetries in SIDIS

    SciTech Connect

    Cisbani, Evaristo

    2010-04-01

    The experiment E06-010 in Hall A at Jefferson Lab took data between November 2008 and February 2009 to directly measure, for the first time, the pion (and kaon) single "neutron" target-spin asymmetry (SSA) in semi-inclusive DIS from a polarized 3He target. Collins, Sivers (and Pretzelosity) neutron asymmetries are going to be extracted from the measured SSA. Details of the experiment are described together with the preliminary results of the ongoing analysis. Near future Hall A experiments on transverse nucleon spin structure are shorty reviewed.

  11. Robot mapping with proximity detectors

    NASA Astrophysics Data System (ADS)

    Malik, Raashid; Prasad, Samuel

    1993-05-01

    Robots operating in unknown environments need to acquire knowledge about the environment to facilitate navigation and other tasks. Control procedures that enable a robot to acquire environment knowledge are referred to as mapping our terrain-acquisition procedures. All motion control procedures are influenced by the underlying models. In this area the significant models are: the robot model, the sensor model and the environment model. In this paper we present a mapping algorithm that uses a sensor model based on a proximity detector. The sensor is capable of detecting the presence or absence of objects within an annular ring of radius R to R + (Delta) , surrounding the robot. The sensor provides no exact range information but does indicate that angular region of contact with an obstacle. The robot is modelled as a disc of radius r (r

  12. 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

  13. 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.

  14. 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…

  15. 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…

  16. Lateral Asymmetries in Infant Melody Perception.

    ERIC Educational Resources Information Center

    Balaban, Marie T.; Anderson, Linda M.; Wisniewski, Amy B.

    1998-01-01

    Two experiments investigated lateral asymmetries in eight-month-olds' perception of contour-altered and contour-preserved melody changes. Found that infants who heard a contour-altered change showed a left-ear advantage, whereas infants who heard a contour-preserved change showed a right-ear advantage. The pattern of lateralization for melody…

  17. Motor asymmetry reduction in older adults.

    PubMed

    Przybyla, Andrzej; Haaland, Kathleen Y; Bagesteiro, Leia B; Sainburg, Robert L

    2011-02-04

    While cerebral lateralization has previously been well documented for many neurobehavioral functions, recent research has shown that as people age, formerly lateralized processes recruit more symmetric patterns of neural activity. Such findings provide the foundation for the model of hemispheric asymmetry reduction in older adults, or "HAROLD"[4]. Previous studies that have measured reaction time and movement time have suggested that aging does not affect manual asymmetries. However, whether these findings can be extended to kinematic variables associated with motor coordination remains largely unknown. The purpose of the current study is to determine whether asymmetries in intralimb coordination are also reduced during the aging process. We examined multidirectional reaching in two different right handed age groups, a younger group from 20 to 40 years of age, and an older group, from 60 to 80 years of age. Measures of final position accuracy, precision, and trajectory linearity showed robust asymmetries between the left and right arm groups of young adults. However, the trajectories and accuracies of the older subjects were symmetric, such that our dependent measures were not significantly different between the right and left arm groups. Our findings extend the HAROLD model to motor behavior, suggesting that aging results in decrements in motor lateralization.

  18. 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…

  19. 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.

  20. 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.

  1. 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.

  2. 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…

  3. 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…

  4. 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…

  5. Task selection cost asymmetry without task switching.

    PubMed

    Bryck, Richard L; Mayr, Ulrch

    2008-02-01

    The switch cost asymmetry (i.e., larger costs when switching from a nondominant into a dominant task than vice versa) has been explained in terms of the trial-to-trial carryover of activation levels required for the dominant versus the nondominant task. However, there is an open question about whether an actual switch in task is in fact necessary to obtain a "selection" cost asymmetry. In Experiments 1 and 2, we modified an alternating-runs paradigm to include either long or short response-to-stimulus intervals (RSIs) after each pair of trials (i.e., AA-AA-BB-BB), thereby inducing selection costs not only at the point of a task switch (i.e., AA-BB), but also between same-task pairs (i.e., AA-AA). Using spatially compatible versus incompatible response rules (Experiment 1) and Stroop word versus color naming (Experiment 2), we found asymmetric effects not only at task-change transitions, but also at task-repeat transitions when the RSI was long (presumably inducing frequent losses of set). In Experiments 3A and 3B, a cost asymmetry for long RSIs was obtained even when competing tasks were separated into alternating single task blocks, but not when the tasks were compared in a between-subjects design. This general pattern cannot be explained by activation carryover models, but is consistent with the idea that the asymmetry arises as a result of interference from long-term memory traces.

  6. Instrumental Asymmetry Reduction in Polarized Electron Beams

    NASA Astrophysics Data System (ADS)

    Fabrikant, M. I.; Trantham, K. W.; Gay, T. J.

    2008-05-01

    We report progress in the reduction of instrumental asymmetries (IAs) related to the photoemission of polarized electrons from GaAs caused by circularly-polarized diode laser beams [1]. Such asymmetries can mask true helicity-dependent interactions between the emitted electrons and chiral targets. Minimization of laser intensity IAs is achieved by chopping two spatially separated light beams with orthogonal polarizations which are recombined and passed through a quarter-wave plate to yield a single beam with rapidly flipping helicity. We have demonstrated the ability to reduce intensity IAs of the laser beam itself to less than 2 x 10-6 [2]. We have also investigated the IAs of the photemission current from the GaAs. At present, we are able to reduce the photoemission asymmetry to values that are comparable to the laser intensity asymmetry. Implications for experiments measuring effects due to electron circular dichroism [3] will be discussed. [1]Trantham K.W. et al J. Phys. B. 28 L543 (1995) [2] Fabrikant M.I. et al submitted to Appl. Opt. [3] Mayer S., Kessler J. Phys. Rev. Lett. 74, 4803 (1995) Funding for this project was provided by Undergraduate Creative Activities and Research Experiences (UCARE) and the National Science Foundation (PHY-0653379).

  7. 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.

  8. 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…

  9. 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.

  10. 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.

  11. 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…

  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. Asymmetric magnetic proximity effect in a Pd/Co/Pd trilayer system

    PubMed Central

    Kim, Dong-Ok; Song, Kyung Mee; Choi, Yongseong; Min, Byoung-Chul; Kim, Jae-Sung; Choi, Jun Woo; Lee, Dong Ryeol

    2016-01-01

    In spintronic devices consisting of ferromagnetic/nonmagnetic systems, the ferromagnet-induced magnetic moment in the adjacent nonmagnetic material significantly influences the spin transport properties. In this study, such magnetic proximity effect in a Pd/Co/Pd trilayer system is investigated by x-ray magnetic circular dichroism and x-ray resonant magnetic reflectivity, which enables magnetic characterizations with element and depth resolution. We observe that the total Pd magnetic moments induced at the top Co/Pd interface are significantly larger than the Pd moments at the bottom Pd/Co interface, whereas transmission electron microscopy and reflectivity analysis indicate the two interfaces are nearly identical structurally. Such asymmetry in magnetic proximity effects could be important for understanding spin transport characteristics in ferromagnetic/nonmagnetic systems and its potential application to spin devices. PMID:27151368

  14. Asymmetric magnetic proximity effect in a Pd/Co/Pd trilayer system

    SciTech Connect

    Kim, Dong -Ok; Song, Kyung Mee; Choi, Yongseong; Min, Byoung -Chul; Kim, Jae -Sung; Choi, Jun Woo; Lee, Dong Ryeol

    2016-05-06

    In spintronic devices consisting of ferromagnetic/nonmagnetic systems, the ferromagnet-induced magnetic moment in the adjacent nonmagnetic material significantly influences the spin transport properties. In this study, such magnetic proximity effect in a Pd/Co/Pd trilayer system is investigated by x-ray magnetic circular dichroism and x-ray resonant magnetic reflectivity, which enables magnetic characterizations with element and depth resolution. We observe that the total Pd magnetic moments induced at the top Co/Pd interface are significantly larger than the Pd moments at the bottom Pd/Co interface, whereas transmission electron microscopy and reflectivity analysis indicate the two interfaces are nearly identical structurally. Furthermore, such asymmetry in magnetic proximity effects could be important for understanding spin transport characteristics in ferromagnetic/nonmagnetic systems and its potential application to spin devices.

  15. Asymmetric magnetic proximity effect in a Pd/Co/Pd trilayer system

    DOE PAGES

    Kim, Dong -Ok; Song, Kyung Mee; Choi, Yongseong; ...

    2016-05-06

    In spintronic devices consisting of ferromagnetic/nonmagnetic systems, the ferromagnet-induced magnetic moment in the adjacent nonmagnetic material significantly influences the spin transport properties. In this study, such magnetic proximity effect in a Pd/Co/Pd trilayer system is investigated by x-ray magnetic circular dichroism and x-ray resonant magnetic reflectivity, which enables magnetic characterizations with element and depth resolution. We observe that the total Pd magnetic moments induced at the top Co/Pd interface are significantly larger than the Pd moments at the bottom Pd/Co interface, whereas transmission electron microscopy and reflectivity analysis indicate the two interfaces are nearly identical structurally. Furthermore, such asymmetry inmore » magnetic proximity effects could be important for understanding spin transport characteristics in ferromagnetic/nonmagnetic systems and its potential application to spin devices.« less

  16. Deformed proximity potential for heavy ion reactions

    SciTech Connect

    Baltz, A.J.

    1989-09-01

    The proximity potential is discussed for the inelastic scattering of a spherical nucleus on a deformed nucleus or the mutual interaction of two deformed nuclei. It is shown that the proximity potential is, in general, geometrically more correct than the usual centerline prescription used in inelastic scattering analyses. For the cases where the proximity potential is inadequate a folding model approach is advocated. Techniques to facilitate the coupled channels analysis are presented. 11 refs., 6 figs.

  17. Facial asymmetry in head and neck rhabdomyosarcoma survivors.

    PubMed

    Schoot, Reineke A; Hol, Marinka L F; Merks, Johannes H M; Suttie, Michael; Slater, Olga; van Lennep, Marinde; Hopman, Saskia M J; Dunaway, David; Syme-Grant, Jonathan; Smeele, Ludi E; Zwinderman, Koos H; Caron, Huib N; Hammond, Peter

    2017-10-01

    Radiotherapy is essential for achieving and maintaining local control in head and neck rhabdomyosarcoma (HNRMS) patients. However, radiotherapy may cause outgrowth disturbances of facial bone and soft tissue, resulting in facial asymmetry. The aim of this study was to develop a method to visualize and measure facial asymmetry in HNRMS survivors using three-dimensional (3D) imaging techniques. Facial deformity was evaluated in a multidisciplinary clinical assessment of 75 HNRMS survivors, treated with external beam radiotherapy (EBRT, n = 26) or Ablative surgery, MOulage brachytherapy, and REconstruction (AMORE, n = 49). Individual facial asymmetry was measured using 3D photogrammetry and expressed in a raw asymmetry index and a normalized sex-age-ethnicity-matched asymmetry signature weight. Facial asymmetry was also compared between British and Dutch controls and between survivors and their matched controls. Facial asymmetry was more pronounced with increasing age (P < 0.01) in British controls compared with Dutch controls (P = 0.04). Survivors developed more facial asymmetry than matched controls (P < 0.001). The clinical assessment of facial deformity correlated with the raw asymmetry index (r = 0.60, P < 0.001). 3D imaging can be used for objective measurement of facial asymmetry in HNRMS survivors. The raw asymmetry index correlated with a clinical assessment of facial deformity. Comparisons between treatment groups seemed inappropriate given the differences in facial asymmetry between British and Dutch controls. In future studies, pretreatment images could act as matched controls for posttreatment evaluation. © 2017 Wiley Periodicals, Inc.

  18. Biological predictors of mandibular asymmetries in children with mixed dentition.

    PubMed

    Sop, Ivana; Mady Maricic, Barbara; Pavlic, Andrej; Legovic, Mario; Spalj, Stjepan

    2016-09-01

    The objective was to investigate the severity of skeletal mandibular asymmetry in children with mixed dentition and other factors associated with asymmetry. The study was cross sectional, with stratified sampling according to malocclusion type consisting of 205 subjects with mixed dentition (median 10, interquartile range 9-11 years). There were 59 subjects presenting Class II/1, 77 Class II/2, and 69 Class III. The mandibular asymmetry has been estimated from orthopantomograms using the Habets' method and the dental maturation by Demirjian's method. The sagittal skeletal relationship and facial growth pattern were assessed from lateral cephalograms. Asymmetries in general, were not rare and were more present in the condylar height rather than in the height of the ramus. The highest severity of condylar asymmetry was in Class II/2 subjects (median of asymmetry index 7.3; 64% subjects exhibiting moderate and severe asymmetry), while the Class III subjects exhibited the highest severity of both ramus and total height asymmetry (2.1; 13% and 2.0; 15%, respectively). Multiple logistic regression unveiled male gender as the only predictor of moderate or significant overall asymmetry. Dental age, the difference between dental and chronological age, and facial growth pattern were not significant predictors of asymmetries. Overall, asymmetries in mixed dentition cannot be considered rare; however, no strong relationships between asymmetry and observed biological factors were found.

  19. Regional differences in cerebral asymmetries of human cortical white matter.

    PubMed

    Iwabuchi, Sarina J; Häberling, Isabelle S; Badzakova-Trajkov, Gjurgjica; Patston, Lucy L M; Waldie, Karen E; Tippett, Lynette J; Corballis, Michael C; Kirk, Ian J

    2011-11-01

    The form of the structural asymmetries across the cerebral hemispheres, that support well-established functional asymmetries, are not well understood. Although, many previous studies have investigated structural differences in areas associated with strong functional asymmetries, such as language processes, regions of the brain with less well established functional laterality have received less attention. The current study aims to address this by exploring global white matter asymmetries of the healthy human brain using diffusion tensor imaging (DTI) and tractography. DTI was conducted on twenty-nine healthy right-handed males, and pathways from the four major lobes were reconstructed using probabilistic tractography. Mean FA, parallel and perpendicular diffusion values were calculated and compared across hemispheres for each pathway generated. Significant asymmetries in the parietal (rightward asymmetry) and occipital (leftward asymmetry) pathways were found in FA measures. However, asymmetric patterns in parallel and/or perpendicular diffusion were observed in all four lobes, even in pathways with symmetrical FA. For instance, significant rightward asymmetry in parallel diffusion was found in the parietal and frontal lobes, whereas significant leftward asymmetry was found in the temporal and occipital lobes. We suggest that these different patterns of diffusion asymmetry reflect differences in microanatomy that support the known patterns of differential functional asymmetry. The different directions of anatomical asymmetry support the notion that there may be a number of different lateralising influences operating in the brain.

  20. Mass predicts web asymmetry in Nephila spiders.

    PubMed

    Kuntner, Matjaz; Gregoric, Matjaz; Li, Daiqin

    2010-12-01

    The architecture of vertical aerial orb webs may be affected by spider size and gravity or by the available web space, in addition to phylogenetic and/or developmental factors. Vertical orb web asymmetry measured by hub displacement has been shown to increase in bigger and heavier spiders; however, previous studies have mostly focused on adult and subadult spiders or on several size classes with measured size parameters but no mass. Both estimations are suboptimal because (1) adult orb web spiders may not invest heavily in optimal web construction, whereas juveniles do; (2) size class/developmental stage is difficult to estimate in the field and is thus subjective, and (3) mass scales differently to size and is therefore more important in predicting aerial foraging success due to gravity. We studied vertical web asymmetry in a giant orb web spider, Nephila pilipes, across a wide range of size classes/developmental stages and tested the hypothesis that vertical web asymmetry (measured as hub displacement) is affected by gravity. On a sample of 100 webs, we found that hubs were more displaced in heavier and larger juveniles and that spider mass explained vertical web asymmetry better than other measures of spider size (carapace and leg lengths, developmental stage). Quantifying web shape via the ladder index suggested that, unlike in other nephilid taxa, growing Nephila orbs do not become vertically elongated. We conclude that the ontogenetic pattern of progressive vertical web asymmetry in Nephila can be explained by optimal foraging due to gravity, to which the opposing selective force may be high web-building costs in the lower orb. Recent literature finds little support for alternative explanations of ontogenetic orb web allometry such as the size limitation hypothesis and the biogenetic law.

  1. Mass predicts web asymmetry in Nephila spiders

    NASA Astrophysics Data System (ADS)

    Kuntner, Matjaž; Gregorič, Matjaž; Li, Daiqin

    2010-12-01

    The architecture of vertical aerial orb webs may be affected by spider size and gravity or by the available web space, in addition to phylogenetic and/or developmental factors. Vertical orb web asymmetry measured by hub displacement has been shown to increase in bigger and heavier spiders; however, previous studies have mostly focused on adult and subadult spiders or on several size classes with measured size parameters but no mass. Both estimations are suboptimal because (1) adult orb web spiders may not invest heavily in optimal web construction, whereas juveniles do; (2) size class/developmental stage is difficult to estimate in the field and is thus subjective, and (3) mass scales differently to size and is therefore more important in predicting aerial foraging success due to gravity. We studied vertical web asymmetry in a giant orb web spider, Nephila pilipes, across a wide range of size classes/developmental stages and tested the hypothesis that vertical web asymmetry (measured as hub displacement) is affected by gravity. On a sample of 100 webs, we found that hubs were more displaced in heavier and larger juveniles and that spider mass explained vertical web asymmetry better than other measures of spider size (carapace and leg lengths, developmental stage). Quantifying web shape via the ladder index suggested that, unlike in other nephilid taxa, growing Nephila orbs do not become vertically elongated. We conclude that the ontogenetic pattern of progressive vertical web asymmetry in Nephila can be explained by optimal foraging due to gravity, to which the opposing selective force may be high web-building costs in the lower orb. Recent literature finds little support for alternative explanations of ontogenetic orb web allometry such as the size limitation hypothesis and the biogenetic law.

  2. Proximal Priority Laser Therapy: PPLT

    NASA Astrophysics Data System (ADS)

    Ohshiro, Toshio

    2004-09-01

    The author has, in the past, classified treatment methods for pain geometrically as point, line, two-dimensional, three-dimensional treatment and has used these over the years. However as a practitioner of western medicine, the author originally treated pain only directed at the painful site, and encountered cases where local treatment did not suffice. The author proved with SPECT and the Rand Phantom that treating the neck which is the midpoint of the brain, the center of the nervous system and the heart, the center of circulation, increased cerebral blood flow and also that laser emitted to neck will reach the spinal chord no matter from where on the neck the laser is emitted. From such research and 25 years of clinical experience, the author has created an anatomy based, systemic treatment method called the Proximal Priority Laser Therapy (PPLT) where not only the cerebral cortex, spinal chord and peripheral nerves are treated but also the tracts of blood vessels and lymph ducts are treated as well. Treatment method and cases are presented herein.

  3. Range gated strip proximity sensor

    DOEpatents

    McEwan, T.E.

    1996-12-03

    A range gated strip proximity sensor uses one set of sensor electronics and a distributed antenna or strip which extends along the perimeter to be sensed. A micro-power RF transmitter is coupled to the first end of the strip and transmits a sequence of RF pulses on the strip to produce a sensor field along the strip. A receiver is coupled to the second end of the strip, and generates a field reference signal in response to the sequence of pulse on the line combined with received electromagnetic energy from reflections in the field. The sensor signals comprise pulses of radio frequency signals having a duration of less than 10 nanoseconds, and a pulse repetition rate on the order of 1 to 10 MegaHertz or less. The duration of the radio frequency pulses is adjusted to control the range of the sensor. An RF detector feeds a filter capacitor in response to received pulses on the strip line to produce a field reference signal representing the average amplitude of the received pulses. When a received pulse is mixed with a received echo, the mixing causes a fluctuation in the amplitude of the field reference signal, providing a range-limited Doppler type signature of a field disturbance. 6 figs.

  4. Range gated strip proximity sensor

    DOEpatents

    McEwan, Thomas E.

    1996-01-01

    A range gated strip proximity sensor uses one set of sensor electronics and a distributed antenna or strip which extends along the perimeter to be sensed. A micro-power RF transmitter is coupled to the first end of the strip and transmits a sequence of RF pulses on the strip to produce a sensor field along the strip. A receiver is coupled to the second end of the strip, and generates a field reference signal in response to the sequence of pulse on the line combined with received electromagnetic energy from reflections in the field. The sensor signals comprise pulses of radio frequency signals having a duration of less than 10 nanoseconds, and a pulse repetition rate on the order of 1 to 10 MegaHertz or less. The duration of the radio frequency pulses is adjusted to control the range of the sensor. An RF detector feeds a filter capacitor in response to received pulses on the strip line to produce a field reference signal representing the average amplitude of the received pulses. When a received pulse is mixed with a received echo, the mixing causes a fluctuation in the amplitude of the field reference signal, providing a range-limited Doppler type signature of a field disturbance.

  5. 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

  6. Nanoscale and proximity effects on low-dimensional helical magnetic structures

    NASA Astrophysics Data System (ADS)

    Sandratskii, Leonid; Fisher, J.; Park, S.; Ouazi, S.; Sander, D.; Kirschner, J.

    We combine symmetry arguments, first-principles calculations and spin-resolved STS measurements to study a 2D helical magnet of some nm extension in proximity to ferromagnetic Co and vacuum regions. Considering the prototypical helical 2D system, an Fe bilayer with intrinsic helical spin structure (1), we report a non-uniform distortion of the spin helix which depends on the lateral extension of the bilayer and on the proximity to either Co or vacuum. The proximity effect manifests itself in different modifications of the magnetic and electronic structures of Fe in vicinity of the interfaces with Co and vacuum. These nanosize and proximity effects have not been discussed before. We demonstrate that, in contrast to an ideal helix of infinite length, the lack of symmetry of the nm-long distorted Fe spin helix, induces an energy dependence of the direction of the electronic magnetization which is revealed in the measured energy dependence of the spin-asymmetry of the differential tunneling conductance. (1) Phark, S. H.; Fischer, J. A.; Corbetta, M.; Sander, D.; Nakamura, K. & Kirschner, J. Reduced-dimensionality-induced helimagnetism in iron nanoislands Nat Commun 5 (2014) 5183.

  7. Anomalous CMB north-south asymmetry

    SciTech Connect

    Bernui, Armando

    2008-09-15

    Several accurate analyses have revealed a statistically significant north-south ecliptic asymmetry in the large-angle correlations strength of the cosmic microwave background (CMB) radiation temperature field data from the Wilkinson Microwave Anisotropy Probe (WMAP). This asymmetry is inconsistent with the statistical isotropy expected in the concordance cosmological model {lambda}CDM. It has been suggested that a possible cause-effect relationship exists between this large-angle anisotropy and the anomalous CMB quadrupole-octopole planes alignment. In turn, this later phenomenon (or both) would be a consequence of one or more of the following undesired effects in CMB data: a systematic error in the data processing or in the instrument characterization, residual foregrounds, and large-angle correlations induced by the incomplete sky CMB data (cut-sky masks are needed to reject galactic foregrounds). Here, it is proved that the north-south asymmetry is unrelated to the quadrupole (l=2) and the octopole (l=3) properties because we find, at high confidence levels, such large-angle anisotropy in three- and five-year WMAP CMB maps containing only the multipole components 4{<=}l{<=}10. The statistical significance depends on both, the CMB map analyzed as well as the cut-sky mask applied to exclude foregrounds. In general, we obtain that the significance level of the north-south asymmetry is less in five-year WMAP data with KQ75 (> or approx. 90% CL) than it is in three-year data with Kp0 (> or approx. 96% CL). For instance, in the WMAP internal linear combination (ILC)-five-year map with the KQ75 mask (a sky cut of 28.4%) this phenomenon is observed at 92.7% CL, whereas for the WMAP ILC-three-year map with the Kp0 mask (a sky cut of 23.5%) this phenomenon appears at 96.5% CL. Moreover, it is also shown that this hemispherical asymmetry is unlikely due to systematics or foreground contaminants, because it is present in single-frequency, multifrequency, and cleaned ILC

  8. Proximal Participation: A Pathway into Work

    ERIC Educational Resources Information Center

    Chan, Selena

    2013-01-01

    In a longitudinal case study of apprentices, the term proximal participation was coined to describe the entry process of young people, with unclear career destinations, into the trade of baking. This article unravels the significance of proximal participation in the decision-making processes of young people who enter a trade through initial…

  9. Grouping by Proximity in Haptic Contour Detection

    PubMed Central

    Overvliet, Krista E.; Krampe, Ralf Th.; Wagemans, Johan

    2013-01-01

    We investigated the applicability of the Gestalt principle of perceptual grouping by proximity in the haptic modality. To do so, we investigated the influence of element proximity on haptic contour detection. In the course of four sessions ten participants performed a haptic contour detection task in which they freely explored a haptic random dot display that contained a contour in 50% of the trials. A contour was defined by a higher density of elements (raised dots), relative to the background surface. Proximity of the contour elements as well as the average proximity of background elements was systematically varied. We hypothesized that if proximity of contour elements influences haptic contour detection, detection will be more likely when contour elements are in closer proximity. This should be irrespective of the ratio with the proximity of the background elements. Results showed indeed that the closer the contour elements were, the higher the detection rates. Moreover, this was the case independent of the contour/background ratio. We conclude that the Gestalt law of proximity applies to haptic contour detection. PMID:23762364

  10. Sugar proximity and human grip strength.

    PubMed

    Quintanar, A F; Hill, T V

    1988-12-01

    In a double-blind experiment with 90 undergraduate students the hypothesis was tested that proximity to sugar reduces human grip strength. An earlier study indicated that sugar proximity does indeed significantly reduce human grip strength. When additional controls were added to this design to reduce random sampling error, the hypothesis was not supported.

  11. Proximal Participation: A Pathway into Work

    ERIC Educational Resources Information Center

    Chan, Selena

    2013-01-01

    In a longitudinal case study of apprentices, the term proximal participation was coined to describe the entry process of young people, with unclear career destinations, into the trade of baking. This article unravels the significance of proximal participation in the decision-making processes of young people who enter a trade through initial…

  12. Grouping by proximity in haptic contour detection.

    PubMed

    Overvliet, Krista E; Krampe, Ralf Th; Wagemans, Johan

    2013-01-01

    We investigated the applicability of the Gestalt principle of perceptual grouping by proximity in the haptic modality. To do so, we investigated the influence of element proximity on haptic contour detection. In the course of four sessions ten participants performed a haptic contour detection task in which they freely explored a haptic random dot display that contained a contour in 50% of the trials. A contour was defined by a higher density of elements (raised dots), relative to the background surface. Proximity of the contour elements as well as the average proximity of background elements was systematically varied. We hypothesized that if proximity of contour elements influences haptic contour detection, detection will be more likely when contour elements are in closer proximity. This should be irrespective of the ratio with the proximity of the background elements. Results showed indeed that the closer the contour elements were, the higher the detection rates. Moreover, this was the case independent of the contour/background ratio. We conclude that the Gestalt law of proximity applies to haptic contour detection.

  13. Is there an association between skeletal asymmetry and tooth absence?

    PubMed Central

    Thiesen, Guilherme; Gribel, Bruno Frazão; Pereira, Keila Cristina Rausch; Freitas, Maria Perpetua Mota

    2016-01-01

    ABSTRACT Introduction: Facial skeletal asymmetry is commonly found in humans and its main characteristic is menton deviation. The literature suggests that occlusal and masticatory problems arising from tooth absence could be related to the development of such asymmetries. Objective: The aim of this cross-sectional study was to estimate the prevalence of mandibular skeletal asymmetries and to investigate its association with posterior tooth absences. Methods: Tomographic images of 952 individuals aged from 18 to 75 years old were used. Asymmetry was the analyzed outcome, and it was categorized into three groups according to gnathion displacement in relation to the midsagittal plane (relative symmetry, moderate asymmetry, and severe asymmetry). Patients were sorted by the presence of all posterior teeth, unilateral posterior tooth absence, or bilateral posterior tooth absence. Chi-square test with a significance level of 5% was used to verify the association between posterior tooth absence and asymmetry. Results: Results show relative symmetry present in 55.3% of the sample, as well as the prevalence of 27.3% for moderate mandibular asymmetry and 17.4% for severe asymmetry. Moderate and severe mandibular asymmetries occurred in a higher proportion in patients with unilateral posterior tooth absence. However, there was no statistically significant difference between the analyzed groups (p = 0.691). Conclusions: In this study, mandibular asymmetries did not present any association with the absence of teeth on the posterior area of the arch. PMID:27653267

  14. Categories of manual asymmetry and their variation with advancing age.

    PubMed

    Teixeira, Luis A

    2008-06-01

    Manual asymmetries were analyzed in 18- to 63-year-old right-handers in different motor tasks. This analysis aimed at describing the asymmetry profile for each task and assessing their stability across ages. For this purpose, performance of the right and left hands were analyzed in the following aspects: simple reaction time, rate of sequential finger movements, maximum grip force, accuracy in anticipatory timing, rate of repetitive tapping, and rate of drawing movements. In addition, stability of manual preference across ages was assessed through the Edinburgh inventory (Oldfield, 1971). The results indicated different profiles of manual asymmetry, with identification of three categories across tasks: symmetric performance (asymmetry indices close to zero), inconsistent asymmetry (asymmetry indices variable in magnitude and direction), and consistent asymmetry (asymmetry indices favoring a single hand). The different profiles observed in the young adults were stable across ages with two exceptions: decreased lateral asymmetry for maximum grip force and increased asymmetry for sequential drawing in older individuals. These results indicate that manual asymmetries are task specific. Such task specificity is interpreted to be the result of different sensorimotor requirements imposed by each motor task in association with motor experiences accumulated over the lifetime. Analysis of manual preference showed that strength of preference for the right hand was greater in older individuals.

  15. Mandibular asymmetry in patients with the crouzon or apert syndrome.

    PubMed

    Elmi, P; Reitsma, J H; Buschang, P H; Wolvius, E B; Ongkosuwito, E M

    2015-05-01

    The aim of this study was to describe directional and fluctuating mandibular asymmetry over time in children with Crouzon or Apert syndrome. Mandibular asymmetry of children between 7.5 and 14 years of age with Crouzon syndrome (n = 35) and Apert syndrome (n = 24) were compared with controls (n = 327). From panoramic radiographs, mandibular directional and fluctuating asymmetry was determined for the three groups. Multilevel statistical techniques were used to describe mandibular asymmetry changes over time. Patients with Crouzon and Apert syndromes showed statistically significant more fluctuating asymmetry for mandibular measures than did controls. Between the Crouzon and Apert syndromes groups, no statistical differences were found in directional and fluctuating asymmetry. The control group showed statistically significantly more directional asymmetry than did patients with Crouzon or Apert syndrome. The controls showed no change over time for the directional asymmetry of condylar-ramal height; however, the directional asymmetry of the gonial angle increased. Patients with Crouzon syndrome showed side dominance for only condylar-ramal height; whereas, patients with Apert syndrome did not show dominance for any of the measurements. Apert and Crouzon syndromes showed developmental instability, in contrast to the controls. No statistically significant longitudinal differences were found for either the directional or the fluctuating asymmetry between Crouzon and Apert syndromes. Findings for fluctuating and directional asymmetry for both syndromes may indicate an inability to cope with genetic and environmental stress during development and treatment, compared with untreated nonsyndromic individuals.

  16. Handedness and cerebral anatomical asymmetries in young adult males.

    PubMed

    Hervé, Pierre-Yves; Crivello, Fabrice; Perchey, Guy; Mazoyer, Bernard; Tzourio-Mazoyer, Nathalie

    2006-02-15

    Using voxel-based morphometry, we measured the cerebral anatomical asymmetries in a sample of 56 young right-handed males and then compared voxelwise asymmetry indices of these subjects to those of 56 young left-handed males. In the right-handed, the clusters of grey matter asymmetry corresponding to the leftward occipital petalia and planum temporale asymmetries were retrieved. Strong rightward temporo-parietal asymmetries were also observed, but the rightward grey matter asymmetry in the frontal lobe was less massive than previously described. Group comparisons of left- and right-handed subjects' asymmetry maps, performed at a statistical threshold not corrected for multiple comparisons, revealed significant effects of handedness on this pattern of anatomical asymmetry in frontal regions, notably in the lower central and precentral sulci, and also in the planum temporale, with right-handed subjects being more leftward asymmetric. Concerning white matter, although almost no focal differences between left- and right-handed subjects were detected, volumetric analyses at the hemispheric level revealed a leftward asymmetry, which happened to be significantly less marked in the left-handed. This latter result, together with the pattern of leftward white matter asymmetries, suggested that anatomical correlates of the left hemispheric specialization for language would exist in white matter. In the population we studied, differences in anatomical asymmetry between left- and right-handed subjects provided structural arguments for a greater functional ambilaterality in left-handed subjects.

  17. 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.

  18. Observing the top energy asymmetry at the LHC

    NASA Astrophysics Data System (ADS)

    Berge, S.; Westhoff, S.

    2017-01-01

    The top-antitop energy asymmetry is a promising observable of the charge asymmetry in jet-associated top-quark pair production at the LHC. We present new predictions of the energy asymmetry in proton-proton collisions at 13 TeV, including QCD corrections at the next-to-leading perturbative order. The effect of QCD corrections on the observable is moderate. With suitable phase-space cuts, the asymmetry can be enhanced at the cost of reducing the cross section. For instance, for a cross section of 1 pb after cuts, we predict an energy asymmetry of -6. 5-0.2+0.1% at the next-to-leading order in QCD. We also investigate scale uncertainties and parton-shower effects, which partially cancel in the normalized asymmetry. Our results provide a sound basis for a measurement of the energy asymmetry at the LHC during run II.

  19. Collider-Independent tt¯ Forward-Backward Asymmetries

    NASA Astrophysics Data System (ADS)

    Aguilar-Saavedra, J. A.; Juste, A.

    2012-11-01

    We introduce the forward-backward asymmetries Au, Ad corresponding to uu¯, dd¯→tt¯ production, respectively, at hadron colliders. These are collider and center-of-mass independent observables, directly related to the forward-backward and charge asymmetries measured at the Tevatron and the LHC, respectively. We discuss how to extract these asymmetries from data. Because these asymmetries are collider independent, their measurement at these two colliders could elucidate the nature of the anomalous forward-backward asymmetry measured at the Tevatron. Our framework also shows in a model independent fashion that a positive Tevatron asymmetry exceeding the standard model expectation is compatible with the small asymmetry measured at the LHC.

  20. Stochastic left-right neuronal asymmetry in Caenorhabditis elegans.

    PubMed

    Alqadah, Amel; Hsieh, Yi-Wen; Xiong, Rui; Chuang, Chiou-Fen

    2016-12-19

    Left-right asymmetry in the nervous system is observed across species. Defects in left-right cerebral asymmetry are linked to several neurological diseases, but the molecular mechanisms underlying brain asymmetry in vertebrates are still not very well understood. The Caenorhabditis elegans left and right amphid wing 'C' (AWC) olfactory neurons communicate through intercellular calcium signalling in a transient embryonic gap junction neural network to specify two asymmetric subtypes, AWC(OFF) (default) and AWC(ON) (induced), in a stochastic manner. Here, we highlight the molecular mechanisms that establish and maintain stochastic AWC asymmetry. As the components of the AWC asymmetry pathway are highly conserved, insights from the model organism C. elegans may provide a window onto how brain asymmetry develops in humans.This article is part of the themed issue 'Provocative questions in left-right asymmetry'.

  1. GDH Integral on the Proton from Asymmetries

    SciTech Connect

    Prok, Yelena

    2004-05-01

    Inclusive double spin electron asymmetries have been measured by scattering polarized electrons off the solid polarized 15NH3 target in Hall B of Jefferson Lab in 2000-2001. The virtual photon asymmetry A1 (x), the longitudinal spin structure function, g1 (x, Q2), and the first moment, γ1p, have been evaluated for a kinematic range of 0.05 ≥ Q2 ≥ 4.5 GeV2. The extracted results complement the existing data in the resonance region, extending it to lower and higher Q2 regions. The results are important in the study of Q2 evolution of nucleon structure from the hadronic to partonic degrees of freedom.

  2. Local time asymmetries in the Venus thermosphere

    NASA Astrophysics Data System (ADS)

    Alexander, M. J.; Stewart, A. I. F.; Solomon, S. C.; Bougher, S. W.

    1993-06-01

    A comparison is presented of the 130-m images taken in the Venus thermosphere by the Pioneer Venus Orbiter Ultraviolet Spectrometer (PVOUVS) to predictions by a model which incorporates current understanding of the global structure of the thermosphere, the mechanisms which excite the 130-nm transition in O, and the radiative transport of the 130-nm triplet in the thermosphere. The features identified in the data/model comparison appear as a local time asymmetry in B(130) and O at altitudes poleward of 30 deg. Oxygen densities at the evening terminator are typically a factor of 2 higher than those at the morning terminator. This asymmetry in O has never before been observed or predicted in the global thermospheric models.

  3. Beam-Spin Asymmetry Measurements at CLAS

    NASA Astrophysics Data System (ADS)

    Aghasyan, M.

    2008-10-01

    The single-spin asymmetries (SSA) that have been reported recently in semi-inclusive DIS by HERMES, COMPASS and CLAS, have emerged as a powerful tool to access the orbital motion of partons. SSAs could arise in the fragmentation of polarized quarks (Collins effect) and from the interference of wavefunctions with different orbital angular momentum (Sivers effect). The two mechanisms produce different kinematical dependences and their contributions could be separated in measurements of different beam and target single-spin asymmetries. This contribution presents recent results from Jefferson Lab's CLAS detector on beam SSAs in single neutral pion electroproduction off an unpolarized hydrogen targets in the DIS regime (Q^2>1GeV^2,W^2>4GeV^2). The measured kinematical dependences are compared with model predictions.

  4. Interhemispheric Asymmetries in Visual Evoked Potential Amplitude

    DTIC Science & Technology

    1980-06-12

    developed using many experimental techniques. Behavioral tasks have included dichotic listening (Kimura, 1961, 1967), reaction time, and other...channel was digitized by the ARll A-D converter- Fifty epochs of 512 msec were averaged for each brain site in each brain hemisphere for each stimulus...perception of verbal stimuli. Can. J. Psychol. 15: 166-171, 1961. Kimuri, D. Functional asymmetry of the brain in dichotic listening. Cortex 3, 163

  5. LETTER: Synchronization model for stock market asymmetry

    NASA Astrophysics Data System (ADS)

    Donangelo, Raul; Jensen, Mogens H.; Simonsen, Ingve; Sneppen, Kim

    2006-11-01

    The waiting time needed for a stock market index to undergo a given percentage change in its value is found to have an up down asymmetry, which, surprisingly, is not observed for the individual stocks composing that index. To explain this, we introduce a market model consisting of randomly fluctuating stocks that occasionally synchronize their short term draw-downs. These synchronous events are parametrized by a 'fear factor', that reflects the occurrence of dramatic external events which affect the financial market.

  6. W mass and W asymmetry at CDF

    SciTech Connect

    Leone, S. Istituto Nazionale di Fisica Nucleare, Pisa )

    1991-05-01

    The lepton charge asymmetry from W decaying into a lepton and a neutrino is discussed (preliminary result). This measurement gives information on parton distribution functions at low x values. The derivation of the recently published W mass value of 79.91 {plus minus} 0.39 GeV/c{sup 2} is also presented. M{sub W} is used to set an upper limit on the top quark mass. 13 refs., 4 figs., 1 tab.

  7. Female and male orbit asymmetry: Digital analysis.

    PubMed

    Lepich, Tomasz; Dąbek, Józefa; Witkowska, Małgorzata; Jura-Szołtys, Edyta; Bajor, Grzegorz

    2017-01-01

    Standard anthropometric methods applied to measurements of the skull differentials are laden with mistakes stemming from the way the measuring devices are built and from a lack of experience on the part of the researchers. To increase objectivity, digital imaging measurements via computer systems were introduced. The aim of this research was to assess the asymmetry of the male and female orbit with the application of the new graphic methods: raster graphics and vector graphics. The examination was conducted on 184 well-preserved skulls. The photos were taken by a digital camera with high definition. Orbit asymmetry was examined by determining the distance between the centers of gravity of both orbits and the frontal median line d1 and d2. Then angles α and β were appointed. They are defined as angles between the line that runs through craniometrical points mf and ek on the right side (angle α) and on the left side (angle β), and the frontal median line at their crossing point. Distances r2 and r1, which are allocated points between the frontal median lines (LPP), were also set. Angles α and β were also analyzed while comparing the skulls of both genders. Statistically significant differences were only observed in male skulls. However, differences for both genders were noted in parameters d1 and d2. No statistically significant differences were discovered between men and women for parameters r1 and r2. The groups of women and men were merged, being treated as a population; which resulted in the conclusion that there are no statistically significant differences between these parameters. The skull's asymmetry connected to gender and the asymmetry of the right and left sides of examined craniums can be used in criminal examinations as well as in facial reconstructive surgeries.

  8. Hemispheric asymmetry: contributions from brain imaging.

    PubMed

    Hugdahl, Kenneth

    2011-09-01

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

  9. 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

    2014-11-06

    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.

  10. Structural Connectivity Asymmetry in the Neonatal Brain

    PubMed Central

    Ratnarajah, Nagulan; Rifkin-Graboi, Anne; Fortier, Marielle V.; Chong, Yap Seng; Kwek, Kenneth; Saw, Seang-Mei; Godfrey, Keith M; Gluckman, Peter D.; Meaney, Michael J.; Qiu, Anqi

    2014-01-01

    Asymmetry of the neonatal brain is not yet understood at the level of structural connectivity. We utilized DTI deterministic tractography and structural network analysis based on graph theory to determine the pattern of structural connectivity asymmetry in 124 normal neonates. We tracted white matter axonal pathways characterizing interregional connections among brain regions and inferred asymmetry in left and right anatomical network properties. Our findings revealed that in neonates, small-world characteristics were exhibited, but did not differ between the two hemispheres, suggesting that neighboring brain regions connect tightly with each other, and that one region is only a few paths away from any other region within each hemisphere. Moreover, the neonatal brain showed greater structural efficiency in the left hemisphere than that in the right. In neonates, brain regions involved in motor, language, and memory functions play crucial roles in efficient communication in the left hemisphere, while brain regions involved in emotional processes play crucial roles in efficient communication in the right hemisphere. These findings suggest that even at birth, the topology of each cerebral hemisphere is organized in an efficient and compact manner that maps onto asymmetric functional specializations seen in adults, implying lateralized brain functions in infancy. PMID:23501049

  11. Functional Asymmetry in Kinesin and Dynein Dimers

    PubMed Central

    Rank, Katherine C.; Rayment, Ivan

    2012-01-01

    Active transport along the microtubule lattice is a complex process that involves both the Kinesin and Dynein superfamily of motors. Transportation requires sophisticated regulation much of which occurs through the motor’s tail domain. However, a significant portion of this regulation also occurs through structural changes that arise in the motor and the microtubule upon binding. The most obvious structural change being the manifestation of asymmetry. To a first approximation in solution, kinesin dimers exhibit two-fold symmetry, and microtubules, helical symmetry. The higher symmetries of both the kinesin dimers and microtubule lattice are lost on formation of the kinesin-microtubule complex. Loss of symmetry has functional consequences such as an asymmetric hand-over-hand mechanism in plus-end directed kinesins, asymmetric microtubule binding in the Kinesin-14 family, spatially biased stepping in dynein, and cooperative binding of additional motors to the microtubule. This review focuses on how the consequences of asymmetry affect regulation of motor heads within a dimer, dimers within an ensemble of motors, and suggests how these asymmetries may affect regulation of active transport within the cell. PMID:23066835

  12. Functional gait asymmetry of unilateral transfemoral amputees.

    PubMed

    Schaarschmidt, Margrit; Lipfert, Susanne W; Meier-Gratz, Christine; Scholle, Hans-Christoph; Seyfarth, Andre

    2012-08-01

    The aim of prosthetic devices is to mimic the function of biological systems. Numerous investigations have demonstrated significant asymmetries in unilateral amputee gait. The underlying interactions of prosthetic and intact leg are not widely discussed, so far. To get more insight into the functionality of asymmetries, we investigated temporal and kinetic parameters of walking transfemoral amputees wearing the computerized C-Leg and the non-computerized 3R80. Experiments were conducted on an instrumented treadmill at four different walking speeds (0.5, 0.8, 1.1, 1.4m/s) measuring vertical and horizontal ground reaction forces. Single support, double support and contact times, vertical and horizontal impulses as well as their asymmetry factors were calculated. Gait patterns were similar for both prosthetic knee joints, manifesting in (i) reduced stance times of the prosthetic leg, (ii) prolonged load transfer during double support from intact to prosthetic leg at lower speeds, (iii) reduced vertical and horizontal impulses of the prosthetic leg, (iv) net accelerating horizontal impulses during contact of the prosthetic leg, (v) missing impacts at touch-down of the prosthetic leg. Our results suggest that deficits of the prosthetic leg like missing active knee extension and ankle push-off are compensated by the intact leg. The altered touch-down configuration for the prosthetic leg enables it to provide forward propulsion while load bearing is largely shifted to the intact leg. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Structural connectivity asymmetry in the neonatal brain.

    PubMed

    Ratnarajah, Nagulan; Rifkin-Graboi, Anne; Fortier, Marielle V; Chong, Yap Seng; Kwek, Kenneth; Saw, Seang-Mei; Godfrey, Keith M; Gluckman, Peter D; Meaney, Michael J; Qiu, Anqi

    2013-07-15

    Asymmetry of the neonatal brain is not yet understood at the level of structural connectivity. We utilized DTI deterministic tractography and structural network analysis based on graph theory to determine the pattern of structural connectivity asymmetry in 124 normal neonates. We tracted white matter axonal pathways characterizing interregional connections among brain regions and inferred asymmetry in left and right anatomical network properties. Our findings revealed that in neonates, small-world characteristics were exhibited, but did not differ between the two hemispheres, suggesting that neighboring brain regions connect tightly with each other, and that one region is only a few paths away from any other region within each hemisphere. Moreover, the neonatal brain showed greater structural efficiency in the left hemisphere than that in the right. In neonates, brain regions involved in motor, language, and memory functions play crucial roles in efficient communication in the left hemisphere, while brain regions involved in emotional processes play crucial roles in efficient communication in the right hemisphere. These findings suggest that even at birth, the topology of each cerebral hemisphere is organized in an efficient and compact manner that maps onto asymmetric functional specializations seen in adults, implying lateralized brain functions in infancy.

  14. Asymmetry of Raman scattering by structure variation in space.

    PubMed

    Wang, Ridong; Yuan, Pengyu; Han, Meng; Xu, Shen; Wang, Tianyu; Wang, Xinwei

    2017-07-24

    We report on the discovery of asymmetries of Raman scattering along one scanning direction, between two scanning directions, and by structure variation of the sample in space. Asymmetry of Raman shift along the x direction, and the asymmetry of Raman shift and linewidth between the two scanning directions (x and y) are found for a 1210 nm diameter silica particle. The observed asymmetries are confirmed by further 2D Raman scanning of the same particle. To further explore the asymmetry of Raman scattering, glass fibers of three diameters (0.53, 1.00, and 3.20 μm) are scanned along two directions. The asymmetry of Raman shift along each direction, the asymmetry of linewidth along the y direction, and the asymmetry of Raman shift and linewidth between the two scanning directions are discovered. Additionally, 11 nm-thick MoSe2 nanosheets on silicon are used to discover whether an asymmetry of Raman scattering exists at the edge of the nanosheets. One edge of the nanosheet is scanned in four directions and the asymmetry of Raman scattering caused by the step variation is also detected. All the observed Raman scattering asymmetries are explained soundly by the Raman signal diffraction and image shift on the CCD detector arrays of the Raman spectrometer. In practice, to use scanning Raman for surface structure study, great measure has to be taken to consider the structure-induced asymmetries to uncover the real Raman wave number variation by intrinsic material structure. We propose a signal processing method by averaging the scanning points along four directions to eliminate the interference of the edge. This method works well to significantly suppress the asymmetries of Raman properties and uncover the real Raman signal change by structure variation.

  15. Validity and sensitivity of the longitudinal asymmetry index to detect gait asymmetry using Microsoft Kinect data.

    PubMed

    Auvinet, E; Multon, F; Manning, V; Meunier, J; Cobb, J P

    2017-01-01

    Gait asymmetry information is a key point in disease screening and follow-up. Constant Relative Phase (CRP) has been used to quantify within-stride asymmetry index, which requires noise-free and accurate motion capture, which is difficult to obtain in clinical settings. This study explores a new index, the Longitudinal Asymmetry Index (ILong) which is derived using data from a low-cost depth camera (Kinect). ILong is based on depth images averaged over several gait cycles, rather than derived joint positions or angles. This study aims to evaluate (1) the validity of CRP computed with Kinect, (2) the validity and sensitivity of ILong for measuring gait asymmetry based solely on data provided by a depth camera, (3) the clinical applicability of a posteriorly mounted camera system to avoid occlusion caused by the standard front-fitted treadmill consoles and (4) the number of strides needed to reliably calculate ILong. The gait of 15 subjects was recorded concurrently with a marker-based system (MBS) and Kinect, and asymmetry was artificially reproduced by introducing a 5cm sole attached to one foot. CRP computed with Kinect was not reliable. ILong detected this disturbed gait reliably and could be computed from a posteriorly placed Kinect without loss of validity. A minimum of five strides was needed to achieve a correlation coefficient of 0.9 between standard MBS and low-cost depth camera based ILong. ILong provides a clinically pragmatic method for measuring gait asymmetry, with application for improved patient care through enhanced disease, screening, diagnosis and monitoring. Copyright © 2016. Published by Elsevier B.V.

  16. A Brief Index for Proximity Searching

    NASA Astrophysics Data System (ADS)

    Téllez, Eric Sadit; Chávez, Edgar; Camarena-Ibarrola, Antonio

    Many pattern recognition tasks can be modeled as proximity searching. Here the common task is to quickly find all the elements close to a given query without sequentially scanning a very large database.

  17. Promoting proximal formative assessment with relational discourse

    NASA Astrophysics Data System (ADS)

    Scherr, Rachel E.; Close, Hunter G.; McKagan, Sarah B.

    2012-02-01

    The practice of proximal formative assessment - the continual, responsive attention to students' developing understanding as it is expressed in real time - depends on students' sharing their ideas with instructors and on teachers' attending to them. Rogerian psychology presents an account of the conditions under which proximal formative assessment may be promoted or inhibited: (1) Normal classroom conditions, characterized by evaluation and attention to learning targets, may present threats to students' sense of their own competence and value, causing them to conceal their ideas and reducing the potential for proximal formative assessment. (2) In contrast, discourse patterns characterized by positive anticipation and attention to learner ideas increase the potential for proximal formative assessment and promote self-directed learning. We present an analysis methodology based on these principles and demonstrate its utility for understanding episodes of university physics instruction.

  18. 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

  19. Proximity operations for space stations and platforms

    NASA Astrophysics Data System (ADS)

    Lineberry, E. C., Jr.

    1984-10-01

    The present study is concerned with concepts, techniques, and system requirements which would permit 'automated' proximity operations utilizing an unmanned vehicle such as the proposed Orbital Maneuvering Vehicle (OMV). Attention is given to proximity operations mission phases, tethered operations, operational control zones, operation control zone objectives, operational control zone definition, aspects of monitoring and tracking, the departure zone, the rendezvous zone, and coorbiting satellite zones.

  20. Polarization proximity effect in isolator crystal pairs.

    PubMed

    Linzon, Y; Ferrera, M; Razzari, L; Pignolet, A; Morandotti, R

    2008-12-01

    We experimentally study the polarization dynamics (orientation and ellipticity) of near-infrared light transmitted through magneto-optical yttrium iron garnet isolator crystal pairs using a modified balanced detection scheme. When the pair separation is in the submillimeter range, we observed a proximity effect in which the saturation field is reduced by up to 20%. One-dimensional calculations suggest that the proximity effect originates from magnetostatic interactions between the dipole moments of the isolator crystals.

  1. Benign monomelic amyotrophy in a 7-year-old girl with proximal upper limb involvement: case report.

    PubMed

    Yilmaz, Oznur; Alemdaroğlu, Ipek; Karaduman, Ayşe; Haliloğlu, Göknur; Topaloğlu, Haluk

    2011-01-01

    Monomelic amyotrophy (MMA) is a benign motor neuron disease characterized by neurogenic amyotrophy, which usually affects one of the upper or lower extremities. Progression is slow and symptoms are clinically stable. Symptoms are seen in the second or third decades of life. In this study, we present a seven-year-old girl who was diagnosed and directed to the Physiotherapy Department at the age of 5 years and had unilateral proximal upper limb involvement. Family history of the case was recorded. Neurologic evaluation was performed. Range of joint motion, muscle shortness and strength, posture, extremity lengths, gait, timed performance, arm function, and motor and mental maturation were assessed. The physiotherapy program was designed progressively as strengthening and resistive exercises. Motor and mental developmental milestones were normal. There was no limitation in active or passive motion of all joints. She had more flexible joints, scapula alata, asymmetry between shoulder levels, and weakness on proximal muscles of the right upper extremity. In the follow-up assessment at eight months, there was no asymmetry between shoulder levels and scapular symmetry began to improve. Female gender and involvement restricted to one proximal upper limb are rare in the literature. This patient demonstrates the positive effects of physical therapy with early diagnosis of MMA. The rapid recovery of muscle weakness shows the importance of strengthening and resistive exercises applied to specific muscles in the treatment.

  2. Proximity operations considerations affecting spacecraft design

    NASA Astrophysics Data System (ADS)

    Staas, Steven K.

    Experience from several recent spacecraft development programs, such as Space Station Freedom (SSF) and the Orbital Maneuvering Vehicle (OMV) has shown the need for factoring proximity operations considerations into the vehicle design process. Proximity operations, those orbital maneuvers and procedures which involve operation of two or more spacecraft at ranges of less than one nautical mile, are essential to the construction, servicing, and operation of complex spacecraft. Typical proximity operations considerations which drive spacecraft design may be broken into two broad categories; flight profile characteristics and concerns, and use of various spacecraft systems during proximity operations. Proximity operations flight profile concerns include the following: (1) relative approach/separation line; (2) relative orientation of the vehicles; (3) relative translational and rotational rates; (4) vehicle interaction, in the form of thruster plume impingement, mating or demating operations, or uncontrolled contact/collision; and (5) active vehicle piloting. Spacecraft systems used during proximity operations include the following: (1) sensors, such as radar, laser ranging devices, or optical ranging systems; (2) effector hardware, such as thrusters; (3) flight control software; and (4) mating hardware, needed for docking or berthing operations. A discussion of how these factors affect vehicle design follows, addressing both active and passive/cooperative vehicles.

  3. Proximity operations considerations affecting spacecraft design

    NASA Technical Reports Server (NTRS)

    Staas, Steven K.

    1991-01-01

    Experience from several recent spacecraft development programs, such as Space Station Freedom (SSF) and the Orbital Maneuvering Vehicle (OMV) has shown the need for factoring proximity operations considerations into the vehicle design process. Proximity operations, those orbital maneuvers and procedures which involve operation of two or more spacecraft at ranges of less than one nautical mile, are essential to the construction, servicing, and operation of complex spacecraft. Typical proximity operations considerations which drive spacecraft design may be broken into two broad categories; flight profile characteristics and concerns, and use of various spacecraft systems during proximity operations. Proximity operations flight profile concerns include the following: (1) relative approach/separation line; (2) relative orientation of the vehicles; (3) relative translational and rotational rates; (4) vehicle interaction, in the form of thruster plume impingement, mating or demating operations, or uncontrolled contact/collision; and (5) active vehicle piloting. Spacecraft systems used during proximity operations include the following: (1) sensors, such as radar, laser ranging devices, or optical ranging systems; (2) effector hardware, such as thrusters; (3) flight control software; and (4) mating hardware, needed for docking or berthing operations. A discussion of how these factors affect vehicle design follows, addressing both active and passive/cooperative vehicles.

  4. Proximity sensor system development. CRADA final report

    SciTech Connect

    Haley, D.C.; Pigoski, T.M.

    1998-01-01

    Lockheed Martin Energy Research Corporation (LMERC) and Merritt Systems, Inc. (MSI) entered into a Cooperative Research and Development Agreement (CRADA) for the development and demonstration of a compact, modular proximity sensing system suitable for application to a wide class of manipulator systems operated in support of environmental restoration and waste management activities. In teleoperated modes, proximity sensing provides the manipulator operator continuous information regarding the proximity of the manipulator to objects in the workspace. In teleoperated and robotic modes, proximity sensing provides added safety through the implementation of active whole arm collision avoidance capabilities. Oak Ridge National Laboratory (ORNL), managed by LMERC for the United States Department of Energy (DOE), has developed an application specific integrated circuit (ASIC) design for the electronics required to support a modular whole arm proximity sensing system based on the use of capacitive sensors developed at Sandia National Laboratories. The use of ASIC technology greatly reduces the size of the electronics required to support the selected sensor types allowing deployment of many small sensor nodes over a large area of the manipulator surface to provide maximum sensor coverage. The ASIC design also provides a communication interface to support sensor commands from and sensor data transmission to a distributed processing system which allows modular implementation and operation of the sensor system. MSI is a commercial small business specializing in proximity sensing systems based upon infrared and acoustic sensors.

  5. Rare decays and CP asymmetries in charged B decays

    SciTech Connect

    Deshpande, N.G.

    1991-01-01

    The theory of loop induced rare decays and the rate asymmetry due to CP violation in charged B Decays in reviewed. After considering b {yields} s{gamma} and b {yields} se{sup +}e{sup {minus}} decays, the asymmetries for pure penguin process are estimated first. A larger asymmetry can result in those modes where a tree diagram and a penguin diagram interfere, however these estimates are necessarily model dependent. Estimates of Cabbibo suppressed penguins are also considered.

  6. Asymmetry dependence of the caloric curve for mononuclei

    NASA Astrophysics Data System (ADS)

    Hoel, C.; Sobotka, L. G.; Charity, R. J.

    2007-01-01

    The asymmetry dependence of the caloric curve, for mononuclear configurations, is studied as a function of neutron-to-proton asymmetry with a model that allows for independent variation of the neutron and proton surface diffusenesses. The evolution of the effective mass with density and excitation is included in a schematic fashion and the entropies are extracted in a local density approximation. The plateau in the caloric curve displays only a slight sensitivity to the asymmetry.

  7. Anomalies and asymmetries in quark-gluon matter

    SciTech Connect

    Teryaev, O. V.

    2012-06-15

    The manifestations of axial anomaly and related effects in heavy-ion collisions are considered. Special role is played by various asymmetries. The azimuthal correlational asymmetries of neutron pairs at NICA/FAIR energy range may probe the global rotation of strongly interacting matter. The conductivity is related to the angular asymmetries of dilepton pairs. The strong magnetic field generated in heavy-ion collisions leads to the excess of soft dileptons flying predominantly in the scattering plane.

  8. Proximal tibiofibular subluxation relationship to lateral knee pain: a review of proximal tibiofibular joint pathologies.

    PubMed

    Semonian, R H; Denlinger, P M; Duggan, R J

    1995-05-01

    Proximal tibiofibular subluxation is the symptomatic hypermobility of the proximal tibiofibular joint. Pain along the lateral aspect of the knee must be carefully evaluated as the anatomy and biomechanics of this region are very complex. Anatomical variants of the proximal tibiofibular joint may be key to understanding the pathomechanics and, thus, treatment of this joint. The "horizontal" proximal tibiofibular joint has a higher degree of mobility, while the "oblique" joint is relatively immobile to rotational forces on the fibula. Increased fibular external rotation will result in injury to the anterior capsule and ligaments of the proximal tibiofibular joint causing common complaints of "popping" and lateral knee pain. Treatment of proximal tibiofibular subluxation will involve modifications of a patient's activity level and training programs, utilization of a supportive strap, lower leg strengthening, and modifications in the lower kinetic chain biomechanics.

  9. Cell asymmetry correction for temperature modulated differential scanning calorimetry

    SciTech Connect

    Ishikiriyama, K.; Wunderlich, B. |

    1996-12-31

    The quality of measurement of heat capacity by differential scanning calorimetry (DSC) is based on strict symmetry of the twin calorimeter, which is important for temperature-modulated DSC. Heat capacities for sapphire-filled and empty aluminium calorimeters (pans) under designed cell imbalance caused by different pan-masses were measured. In addition, positive and negative signs of asymmetry were explored by analyzing the phase-shift between temperature and heat flow for sapphire and empty runs. The phase shifts change by more than 18{degree} depending on asymmetry sign. Once the asymmetry sign is determined, the asymmetry correction for modulated DSC can be made.

  10. Visual search asymmetries in heavy clutter: implications for display design.

    PubMed

    Yamani, Yusuke; McCarley, Jason S

    2011-06-01

    An experiment aimed to test whether design of symbology to produce visual search asymmetries might facilitate target detection in cluttered displays. A visual search asymmetry exists between two stimuli when a target of one type is found efficiently among distractors of the second type but a target of the second type is found with difficulty among distractors of the first type. Asymmetries have generally been studied within relatively sparse displays. In the present study, the authors tested whether an asymmetry driven by stimulus familiarity persists within heavily cluttered imagery. In this study, 10 participants performed a visual search task using stimuli (canonical vs. reversed Ns) known to produce a search asymmetry. Search stimuli were embedded within geospatial images containing either low or high levels of clutter. A decision theoretic index of sensitivity served as the dependent measure. The search asymmetry was robust against the presence of heavy display clutter. Specifically, sensitivity was greater when the target was a reversed N rather than an N, and this pattern remained within cluttered displays. Time-accuracy analysis revealed that the search asymmetry increased the rate of information accumulation roughly equally within low- and high- clutter images. Search asymmetries are robust against heavy, spatially continuous visual clutter. Design of display symbology to produce visual search asymmetries can offset the costs of visual clutter, maximizing detectability of task-critical information in complex displays.

  11. What determines direction of asymmetry: genes, environment or chance?

    PubMed

    Palmer, A Richard

    2016-12-19

    Conspicuous asymmetries seen in many animals and plants offer diverse opportunities to test how the development of a similar morphological feature has evolved in wildly different types of organisms. One key question is: do common rules govern how direction of asymmetry is determined (symmetry is broken) during ontogeny to yield an asymmetrical individual? Examples from numerous organisms illustrate how diverse this process is. These examples also provide some surprising answers to related questions. Is direction of asymmetry in an individual determined by genes, environment or chance? Is direction of asymmetry determined locally (structure by structure) or globally (at the level of the whole body)? Does direction of asymmetry persist when an asymmetrical structure regenerates following autotomy? The answers vary greatly for asymmetries as diverse as gastropod coiling direction, flatfish eye side, crossbill finch bill crossing, asymmetrical claws in shrimp, lobsters and crabs, katydid sound-producing structures, earwig penises and various plant asymmetries. Several examples also reveal how stochastic asymmetry in mollusc and crustacean early cleavage, in Drosophila oogenesis, and in Caenorhabditis elegans epidermal blast cell movement, is a normal component of deterministic development. Collectively, these examples shed light on the role of genes as leaders or followers in evolution.This article is part of the themed issue 'Provocative questions in left-right asymmetry'. © 2016 The Author(s).

  12. [Asymmetry of antennal grooming in the cockroach (Periplaneta americana)].

    PubMed

    2014-07-01

    The present study was conducted to determine the key features of antennal grooming of male American cockroaches in neutral circumstances. It was shown for the first time that the right antenna was cleaned significantly more often than the left one, which indicates the presence of functional asymmetry of antennal grooming in this insect species. At the same time, no statistically significant asymmetry was found for grooming of antennal bases and legs. Morphological asymmetries of antennae and legs and/or brain lateralization are the plausible sources of observed behavioral asymmetry in antennal grooming.

  13. 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

  14. Asymmetries in gamma scattering by Fe-57.

    NASA Technical Reports Server (NTRS)

    Lee, L. Y.; Goodman, C. D.

    1972-01-01

    Experiments were conducted with a setup in which a Co-57 single-line source was driven by a constant-acceleration motor. The 14.4-keV gamma rays emitted from the iron foil scatterer were detected by a proportional counter filled with krypton and carbon dioxide. The interference for individual Zeeman hyperfine transitions in a magnetic field was calculated. It was found that beside the cos phi angular dependence of line shape asymmetry, there exists a sin phi intensity dependence for some of the hyperfine transitions.

  15. Top Quark Production Asymmetries AFBt and AFBl

    DOE PAGES

    Berger, Edmond L.; Cao, Qing-Hong; Chen, Chuan-Ren; ...

    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.

  16. Centriole asymmetry determines algal cell geometry

    PubMed Central

    Marshall, Wallace F.

    2012-01-01

    The mechanisms that determine the shape and organization of cells remain largely unknown. Green algae such as Chlamydomonas provide excellent model systems for studying cell geometry due to their highly reproducible cell organization. Structural and genetic studies suggest that asymmetry of the centriole (basal body) plays a critical determining role in organizing the internal organization of algal cells, through the attachment of microtubule rootlets and other large fiber systems to specific sets of microtubule triplets on the centriole. Thus to understand cell organization, it will be critical to understand how the different triplets of the centriole come to have distinct molecular identities. PMID:23026116

  17. Membrane phospholipid asymmetry in human thalassemia.

    PubMed

    Kuypers, F A; Yuan, J; Lewis, R A; Snyder, L M; Kiefer, C R; Bunyaratvej, A; Fucharoen, S; Ma, L; Styles, L; de Jong, K; Schrier, S L

    1998-04-15

    Phospholipid asymmetry in the red blood cell (RBC) lipid bilayer is well maintained during the life of the cell, with phosphatidylserine (PS) virtually exclusively located in the inner monolayer. Loss of phospholipid asymmetry, and consequently exposure of PS, is thought to play an important role in red cell pathology. The anemia in the human thalassemias is caused by a combination of ineffective erythropoiesis (intramedullary hemolysis) and a decreased survival of adult RBCs in the peripheral blood. This premature destruction of the thalassemic RBC could in part be due to a loss of phospholipid asymmetry, because cells that expose PS are recognized and removed by macrophages. In addition, PS exposure can play a role in the hypercoagulable state reported to exist in severe beta-thalassemia intermedia. We describe PS exposure in RBCs of 56 comparably anemic patients with different genetic backgrounds of the alpha- or beta-thalassemia phenotype. The use of fluorescently labeled annexin V allowed us to determine loss of phospholipid asymmetry in individual cells. Our data indicate that in a number of thalassemic patients, subpopulations of red cells circulate that expose PS on their outer surface. The number of such cells can vary dramatically from patient to patient, from as low as that found in normal controls (less than 0.2%) up to 20%. Analysis by fluorescent microscopy of beta-thalassemic RBCs indicates that PS on the outer leaflet is distributed either over the entire membrane or localized in areas possibly related to regions rich in membrane-bound alpha-globin chains. We hypothesize that these membrane sites in which iron carrying globin chains accumulate and cause oxidative damage, could be important in the loss of membrane lipid organization. In conclusion, we report the presence of PS-exposing subpopulations of thalassemic RBC that are most likely physiologically important, because they could provide a surface for enhancing hemostasis as recently reported

  18. Developmental asymmetries between horizontal and vertical tracking.

    PubMed

    Grönqvist, Helena; Gredebäck, Gustaf; Hofsten, Claes von

    2006-05-01

    The development of the asymmetry between horizontal and vertical eye tracking was investigated longitudinally at 5, 7, and 9 months of age. The target moved either on a 2D circular trajectory or on a vertical or horizontal 1D sinusoidal trajectory. Saccades, smooth pursuit, and head movements were measured. Vertical tracking was found to be inferior to horizontal tracking at all age levels. The results also show that the mechanisms responsible for horizontal and vertical tracking mutually influence one another in the production of 2D visual pursuit. Learning effects were observed within-trials but no transfer between trials was found.

  19. 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…

  20. 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…

  1. Automatic analysis of cerebral asymmetry: an exploratory study of the relationship between brain torque and planum temporale asymmetry.

    PubMed

    Barrick, Thomas R; Mackay, Clare E; Prima, Sylvain; Maes, Frederik; Vandermeulen, Dirk; Crow, Timothy J; Roberts, Neil

    2005-02-01

    Leftward occipital and rightward frontal lobe asymmetry (brain torque) and leftward planum temporale asymmetry have been consistently reported in postmortem and in vivo neuroimaging studies of the human brain. Here automatic image analysis techniques are applied to quantify global and local asymmetries, and investigate the relationship between brain torque and planum temporale asymmetries on T1-weighted magnetic resonance (MR) images of 30 right-handed young healthy subjects (15 male, 15 female). Previously described automatic cerebral hemisphere extraction and 3D interhemispheric reflection-based methods for studying brain asymmetry are applied with a new technique, LowD (Low Dimension), which enables automatic quantification of brain torque. LowD integrates extracted left and right cerebral hemispheres in columns orthogonal to the midsagittal plane (2D column maps), and subsequently integrates slices along the brain's anterior-posterior axis (1D slice profiles). A torque index defined as the magnitude of occipital and frontal lobe asymmetry is computed allowing exploratory investigation of relationships between this global asymmetry and local asymmetries found in the planum temporale. LowD detected significant torque in the 30 subjects with occipital and frontal components found to be highly correlated (P<0.02). Significant leftward planum temporale asymmetry was detected (P<0.05), and the torque index correlated with planum temporale asymmetry (P<0.001). However, torque and total brain volume were not correlated. Therefore, although components of cerebral asymmetry may be related, their magnitude is not influenced by total hemisphere volume. LowD provides increased sensitivity for detection and quantification of brain torque on an individual subject basis, and future studies will apply these techniques to investigate the relationship between cerebral asymmetry and functional laterality.

  2. The evolutionary origin of flatfish asymmetry.

    PubMed

    Friedman, Matt

    2008-07-10

    All adult flatfishes (Pleuronectiformes), including the gastronomically familiar plaice, sole, turbot and halibut, have highly asymmetrical skulls, with both eyes placed on one side of the head. This arrangement, one of the most extraordinary anatomical specializations among vertebrates, arises through migration of one eye during late larval development. Although the transformation of symmetrical larvae into asymmetrical juveniles is well documented, the evolutionary origins of flatfish asymmetry are uncertain because there are no transitional forms linking flatfishes with their symmetrical relatives. The supposed inviability of such intermediates gave pleuronectiforms a prominent role in evolutionary debates, leading to attacks on natural selection and arguments for saltatory change. Here I show that Amphistium and the new genus Heteronectes, both extinct spiny-finned fishes from the Eocene epoch of Europe, are the most primitive pleuronectiforms known. The orbital region of the skull in both taxa is strongly asymmetrical, as in living flatfishes, but these genera retain many primitive characters unknown in extant forms. Most remarkably, orbital migration was incomplete in Amphistium and Heteronectes, with eyes remaining on opposite sides of the head in post-metamorphic individuals. This condition is intermediate between that in living pleuronectiforms and the arrangement found in other fishes. Amphistium and Heteronectes indicate that the evolution of the profound cranial asymmetry of extant flatfishes was gradual in nature.

  3. Line profile asymmetries in chromospherically active stars

    NASA Technical Reports Server (NTRS)

    Dempsey, Robert C.; Bopp, Bernard W.; Strassmeier, Klaus G.; Granados, Arno F.; Henry, Gregory W.; Hall, Douglas S.

    1992-01-01

    A powerful, new probe of chromospheric activity, cross-correlation, has been developed and applied to a variety of stars. In this particular application, an entire CCD spectrum of an active star is correlated with the spectrum of a narrow-line, inactive star of similar spectral type and luminosity class. Using a number of strong lines in this manner enables the detection of absorption profile asymmetries at moderate resolution (lambda/Delta lambda about 40,000) and S/N 150:1. This technique has been applied to 14 systems mostly RS CVn's, with 10 not greater than nu sin i not greater than 50 km/s and P not less than 7 d. Distortions were detected for the first time in five systems: Sigma Gem, IM Peg, GX Lib, UV Crb, and Zeta And. Detailed modeling, incorporating both spectral line profiles and broad-band photometry, is applied to Sigma Gem. Profile asymmetries for this star are fitted by two high-latitude spots covering 5 percent of the stellar surface. The derived spot temperature of 3400 K is lower than found in previous studies. In addition, two well-known systems have been studied: HD 199178 and V711 Tau. Polar spots are found on both.

  4. Configurational asymmetry in vernier offset detection.

    PubMed

    Karim, A K M Rezaul; Kojima, Haruyuki

    2010-10-06

    Two psychophysical experiments were conducted at the horizontal and vertical orientations respectively, demonstrating substantial main effect of configuration, but no effect of offset direction on vernier acuity. In Experiment 1, a pair of horizontal bars were arranged side by side with a large gap between them. The observers were, on average, significantly better at discriminating a vertical offset if the right-hand bar was below the left-hand bar than vice versa, regardless of which bar they experienced as displaced and which as constant. A similar asymmetry was evident in Experiment 2 where observers judged horizontal offset for a pair of vertically oriented bars, where one was placed above the other. In this case average performance was better if the upper bar was on the right of the lower bar rather than on its left. There were large individual variations in the asymmetrical trend, but the effect could not be explained by subjective response bias. Furthermore, vernier acuity improved significantly and the asymmetry decreased more or less as a function of training. The average asymmetrical trend was consistent across training days and across two orientations, which indicates that the processing of line vernier stimuli is possibly configuration-specific in the cardinal orientation.

  5. Configurational asymmetry in vernier offset detection

    PubMed Central

    Karim, A. K. M. Rezaul; Kojima, Haruyuki

    2010-01-01

    Two psychophysical experiments were conducted at the horizontal and vertical orientations respectively, demonstrating substantial main effect of configuration, but no effect of offset direction on vernier acuity. In Experiment 1, a pair of horizontal bars were arranged side by side with a large gap between them. The observers were, on average, significantly better at discriminating a vertical offset if the right-hand bar was below the left-hand bar than vice versa, regardless of which bar they experienced as displaced and which as constant. A similar asymmetry was evident in Experiment 2 where observers judged horizontal offset for a pair of vertically oriented bars, where one was placed above the other. In this case average performance was better if the upper bar was on the right of the lower bar rather than on its left. There were large individual variations in the asymmetrical trend, but the effect could not be explained by subjective response bias. Furthermore, vernier acuity improved significantly and the asymmetry decreased more or less as a function of training. The average asymmetrical trend was consistent across training days and across two orientations, which indicates that the processing of line vernier stimuli is possibly configuration-specific in the cardinal orientation. PMID:20930953

  6. 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.

  7. 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

  8. Does urban poverty increase body fluctuating asymmetry?

    PubMed

    Ozener, Bariş

    2011-12-01

    Perturbations during development leave enduring signs on the adult body. Fluctuating asymmetry (FA) is a good bio-indicator of stress during ontogeny. The aim of this study is to determine the effect of urban poverty on the fluctuating asymmetry of young Turkish males. Young males from a lower socioeconomic group (N = 140, Mean age = 18.17 +/- 0.61) were selected from slum areas of Ankara, the capital of Turkey, where urban poverty is intense. An upper socioeconomic group, on the other hand, consisted of students from two private colleges and included children from some of the richest families in Turkey (N = 120, Mean age = 18.08 +/- 0.54). Eight anthropometric traits of all subjects were measured. Considering the seven measurements demonstrate ideal FA, the individuals living in poor areas of the city displayed higher FA. The discrepancy between the two groups was even greater for a measure of composite FA. In conclusion, poor living conditions in Ankara, where urban poverty is intense, adversely impact the developmental stability of young Turkish males.

  9. Effects of Vent Asymmetry on Explosive Eruptions

    NASA Astrophysics Data System (ADS)

    Sim, S.; Ogden, D. E.

    2012-12-01

    Current computer models of volcanic eruptions are typically based on symmetric vent and conduit geometries. However, in natural settings, these features are rarely perfectly symmetric. For example, the May 18, 1980 eruption of Mount St Helens (MSH) took place through a highly asymmetrical crater due to the preceding landslide and subsequent vent erosion. In supersonic, high pressure eruptions, such as what may have occurred at MSH, vent and crater asymmetry can strongly affect the directionality of the gas-thrust region. These effects on eruption direction may have implications for the formation of lateral blasts and pyroclastic density currents (PDCs). Here, we present preliminary results from numerical simulations using CartaBlanca, a Java based simulation tool for non-linear physics as developed at Los Alamos National Laboratory. Using 2D time-dependent simulations of explosive volcanic eruptions, we study the effects of vent asymmetry on a variety of eruptive conditions. Preliminary results suggest that asymmetric vent shape may provide an additional mechanism for the formation of lateral blasts and PDCs.

  10. Quantum Correlations Evolution Asymmetry in Quantum Channels

    NASA Astrophysics Data System (ADS)

    Li, Meng; Huang, Yun-Feng; Guo, Guang-Can

    2017-03-01

    It was demonstrated that the entanglement evolution of a specially designed quantum state in the bistochastic channel is asymmetric. In this work, we generalize the study of the quantum correlations, including entanglement and quantum discord, evolution asymmetry to various quantum channels. We found that the asymmetry of entanglement and quantum discord only occurs in some special quantum channels, and the behavior of the entanglement evolution may be quite different from the behavior of the quantum discord evolution. To quantum entanglement, in some channels it decreases monotonously with the increase of the quantum channel intensity. In some other channels, when we increase the intensity of the quantum channel, it decreases at first, then keeps zero for some time, and then rises up. To quantum discord, the evolution becomes more complex and you may find that it evolutes unsmoothly at some points. These results illustrate the strong dependence of the quantum correlations evolution on the property of the quantum channels. Supported by the National Natural Science Foundation of China under Grant Nos. 61327901, 61490711, 61225025, 11474268, and the Fundamental Research Funds for the Central Universities under Grant No. WK2470000018

  11. A Search for Hemispheric Asymmetry on Triton

    NASA Astrophysics Data System (ADS)

    McIntosh, C. M.; Storrs, A. D.

    2004-12-01

    We will present reconstructed images of Neptune's largest satellite Triton as part of an investigation of hemispheric asymmetry. The images we observed from the Hubble Space Telescope in July of 1997, using the Wide Field/Planetary Camera. The images were taken in several filters: F439W, F555W, and F791W. Image restoration was performed using the MISTRAL program (Mugnier, Fusco, and Conan 2003). We present the ratio between the filters to determine if there is any hemispheric color asymmetry at this time. The photometry of Triton appears normal in this data although Hicks and Buratti (2004) observe Triton to be anomalously red in August of 1997. References: Hicks, M.D., and Buratti, B.J. (2004): "The Spectral Variability of Triton from 1997-2000", Icarus 171 pp. 210-218 Mugnier, L.M., T. Fusco, and J.-M. Conan, 2003. "MISTRAL: a Myopic Edge-Preserving Image Restoration Method. Applicaton to Astronomical Adaptive Optics Corrected Long-Exposure Images." JOSA A (submitted)

  12. Breast asymmetry: presentation of a giant fibroadenoma.

    PubMed

    Park, Christopher A; David, Lisa R; Argenta, Louis C

    2006-01-01

    Patients often present to plastic surgeons with breast asymmetry of unknown etiology. Many patients are females in late adolescence and present complaining of a hypoplastic breast on the smaller side. However, full evaluation may reveal that the larger breast contains the abnormality. Fibroadenomas typically present as firm, mobile, painless, easily palpable breast nodules. However, giant fibroadenomas can present as unilateral macromastia without definable borders or texture differences. Diagnosis is essential since fibroadenomas tend to persist and grow. However, physical examination and standard radiographic evaluations (mammograms and ultrasounds) fail to clarify the diagnosis in many cases. Magnetic resonance imaging (MRI) has improved preoperative diagnosis, but tissue diagnosis is frequently necessary and resection of giant fibroadenomas is essential as they enlarge to the point of causing psychological detriment or mass effects, including venous congestion, glandular distortion, pressure necrosis, and occasionally ulceration. In this article we review nine patients presenting with unilateral macromastia to a tertiary breast care center with a review of the pertinent literature. The differential diagnosis, evaluation modalities, and treatment options of breast asymmetry and unilateral breast masses are presented. Postexcision breast reconstruction is discussed.

  13. Perceptual asymmetries and handedness: a neglected link?

    PubMed Central

    Marzoli, Daniele; Prete, Giulia; Tommasi, Luca

    2014-01-01

    Healthy individuals tend to weigh in more the left than the right side of visual space in a variety of contexts, ranging from pseudoneglect to perceptual asymmetries for faces. Among the common explanations proposed for the attentional and perceptual advantages of the left visual field, a link with the prevalence of right-handedness in humans has never been suggested, although some evidence seems to converge in favor of a bias of spatial attention toward the region most likely coincident with another person’s right hand during a face-to-face interaction. Such a bias might imply an increased efficiency in monitoring both communicative and aggressive acts, the right limb being more used than the left in both types of behavior. Although attentional and perceptual asymmetries could be linked to right-handedness at the level of phylogeny because of the evolutionarily advantage of directing attention toward the region where others’ dominant hand usually operates, it is also legitimate to question whether, at the ontogenetic level, frequent exposure to right-handed individuals may foster leftward biases. These views are discussed in the light of extant literature, and a number of tests are proposed in order to assess our hypotheses. PMID:24592250

  14. 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.

  15. Two sources of asymmetry-induced transport

    NASA Astrophysics Data System (ADS)

    Eggleston, D. L.

    2010-11-01

    We have added collisional effects to our single-particle codeootnotetextD. L. Eggleston, Phys. Plasmas 14, 012302 (2007). by applying random velocity steps along with a drag force in the particle equation of motion. By following the time variation of the mean square change in radial position we can obtain a diffusion coefficient D which can be compared with analytical theory and experiment. For asymmetries of the form φ1(r)(kz)(φt - lθ) and low collision frequency, there are two contributions to the transport. The first is that given by resonant particle transport theoryootnotetextD. L. Eggleston and T. M. O'Neil, Phys. Plasmas 6, 2699 (1999). and is produced by particles with velocity near ±(lφR- φ)/k, where φR is the azimuthal rotation frequency. The second is produced by the low velocity particles identified in Ref. 2 that are axially trapped in the asymmetry potential. These produce a stronger variation of D with φ with a peak near φ=lφR. The width of the peak δφ increases with center wire bias and decreases with radius, while the height shows the opposite behavior. Diffusion due to axially trapped particles is typically comparable to or larger than that from resonant particles. This may explain the discrepancies between experiments and resonant particle theory.ootnotetextD. L. Eggleston and B. Carrillo, Phys. Plasmas 10, 1308 (2003).

  16. Strangeness asymmetry in the proton sea

    NASA Astrophysics Data System (ADS)

    Alberg, Mary

    2015-10-01

    Meson cloud models describe the proton sea in terms of fluctuations of the proton into meson-baryon pairs. The leading contributions to proton strangeness are from states which contain a kaon and a Lambda or Sigma hyperon. We use a Fock state expansion of the proton in terms of these states to determine the strangeness distributions of the proton in a convolution model, in which the fluctuations are represented by meson-baryon splitting functions, which determine the total strangeness of the proton. Strangeness asymmetry, the difference between momentum distributions of the s and sbar quarks in the proton, arises because the quarks are constituents of different hadrons. For the parton distributions of the s(sbar) quarks in the bare baryons(mesons) of the Fock states, we use light cone wave functions or our statistical model, which expands the bare hadrons in terms of quark-gluon states. We show that strangeness asymmetry depends strongly on the parton distributions used for the hadrons in the cloud. We compare our results to NuTeV and to global parton distributions. This research has been supported in part by NSF Award 1205686.

  17. 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

  18. [Facial asymmetry in children with congenital muscular torticollis after surgical treatment].

    PubMed

    Masłoń, Adrian; Lebiedziński, Radosław; Domzalski, Marcin; Synder, Marek; Grzegorzewski, Andrzej

    2009-01-01

    Asymmetrical position of facial skeleton and movement restriction in the cervical spine in young children could be caused by torticollis mainly muscle origin. We observe miofibrosis of sternocleidomastoid muscle. This face deformation is seen from 0.3 to 1.5% children. Torticollis could be associated with malocclusion, facial asymmetry, vision defect or vertebral body deformation. Muscle stretching is a main type of treatment at infantile age. In the case of faille and in older children sternocleidomastoid myotomy is indicated. The purpose of our study is to analyze facial asymmetry in children after torticollis surgery and determination if surgery performed after 3 years of age is associated with higher risk of facial deformity in long follow up. The study population consisted of 16 patients who underwent sternocleidomastoid tenotomy in proximal and distal part. The control group consisted of 13 persons. Booth groups underwent subjective and objective analysis consisted of computer facial symmetry analysis and measurements of range of motion in the cervical spine. The study group was divided into two subgroups--patients operated before and after 3 years of age. The follow up was 2 to 26 years (mean 13.4 years). The statistical analysis of objective evaluation revealed significant difference in horizontal face axis between subgroups (p<0.05). Range of motion at cervical vertebral column was the same in both groups. Facial asymmetry caused by muscle torticollis is persistent in horizontal axis in long follow up and is more often observed in children operated after 3 years of age, but statistical analysis does not support this thesis.

  19. Soccer Attenuates the Asymmetry of Rectus Abdominis Muscle Observed in Non-Athletes

    PubMed Central

    Idoate, Fernando; Calbet, Jose A. L.; Izquierdo, Mikel; Sanchis-Moysi, Joaquin

    2011-01-01

    Purpose To determine the volume and degree of asymmetry of the rectus abdominis muscle (RA) in professional soccer players. Methods The volume of the RA was determined using magnetic resonance imaging (MRI) in 15 professional male soccer players and 6 non-active male control subjects. Results Soccer players had 26% greater RA volume than controls (P<0.05), due to hypertrophy of both the dominant (28% greater volume, P<0.05) and non-dominant (25% greater volume, P<0.01) sides, after adjusting for age, length of the RA muscle and body mass index (BMI) as covariates. Total volume of the dominant side was similar to the contralateral in soccer players (P = 0.42) and in controls (P = 0.75) (Dominant/non-dominant = 0.99, in both groups). Segmental analysis showed a progressive increase in the degree of side-to-side asymmetry from the first lumbar disc to the pubic symphysis in soccer players (r = 0.80, P<0.05) and in controls (r = 0.75, P<0.05). The slope of the relationship was lower in soccer players, although this trend was not statistically significant (P = 0.14). Conclusions Professional soccer is associated with marked hypertrophy of the rectus abdominis muscle, which achieves a volume that is 26% greater than in non-active controls. Soccer induces the hypertrophy of the non-dominant side in proximal regions and the dominant side in regions closer to pubic symphysis, which attenuates the pattern of asymmetry of rectus abdominis observed in non-active population. It remains to be determined whether the hypertrophy of rectus abdominis in soccer players modifies the risk of injury. PMID:21541351

  20. 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.

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

    PubMed

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

    2015-08-18

    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.

  2. 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…

  3. 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…

  4. 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.…

  5. 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

  6. 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…

  7. 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.…

  8. Jet Asymmetry and the Detection of Odderon Exchange in DIS

    SciTech Connect

    Brodsky, Stanley J.

    1999-10-08

    We show that the asymmetry in the fractional energy of charm versus anticharm jets produced in high energy diffractive photoproduction is sensitive to the interference of the Odderon (C = -) and Pomeron (C = +) exchange amplitudes in QCD. Measurements of this asymmetry at HERA could provide the first evidence for the presence of Odderon exchange in the high energy limit of strong interactions.

  9. Fluctuating asymmetry in waterbirds in relation to mercury exposure

    USGS Publications Warehouse

    Herring, Garth; Eagles-Smith, Collin A.; Ackerman, Josh

    2016-01-01

    The dataset includes the bird species, sex, mercury concentration in breast feathers and whole blood, and the composite measure of fluctuating asymmetry. Statistical models were developed for each species to analyze the relationship between mercury exposure in either breast feathers or whole blood and the composite measure of fluctuating asymmetry, while accounting for the sex of each bird.

  10. Fluctuating asymmetry as a predictor for rowing ergometer performance.

    PubMed

    Longman, D; Stock, J T; Wells, J C K

    2011-08-01

    Fluctuating asymmetry (FA) can be defined as an organism's deviation from perfect bilateral symmetry. FA has been of interest to evolutionary biologists as it may be indicative of the ability of an individual to express its genotype in a stable manner. Asymmetry has been shown to correlate with success in both intra- and inter-sexual selection in various species, including humans. A growing body of knowledge is emerging concerning the relationship between asymmetry and sporting ability. This study seeks to expand upon understanding of developmental stability and athletics by investigating the association between asymmetry and performance in rowers. Both male and female competitors from a range of abilities were tested (76 males and 70 females), with asymmetry being determined through bilateral digit measurements and performance through personal best time over 2000 m on the Concept 2 indoor rowing ergometer. Significant negative correlations were observed between asymmetry and 2000 m ergometer performance in both males and females. The relationship remained significant after adjustment for rowing experience and height. These results suggest that asymmetry may serve as a predictor of potential ability in the sport of rowing. The cause for the association between asymmetry and sporting performance has yet to be identified. © Georg Thieme Verlag KG Stuttgart · New York.

  11. Stabilizing factors of phospholipid asymmetry in the erythrocyte membrane.

    PubMed

    Dressler, V; Haest, C W; Plasa, G; Deuticke, B; Erusalimsky, J D

    1984-08-22

    Transbilayer reorientation (flip) of exogenous lysophospholipids and changes of the transbilayer distribution of endogenous phospholipids were studied in human erythrocytes and membrane vesicles. (1) Exogenous lysophosphatidylserine irreversibly accumulates in the inner membrane layer of resealed ghosts of human erythrocytes. (2) This accumulation even occurs after complete loss of asymmetric distribution of endogenous phosphatidylethanolamine and partial loss of phosphatidylserine asymmetry in diamide-treated cells. (3) Formation of inside-out and right-side-out vesicles from erythrocyte membranes results in a loss of endogenous phospholipid asymmetry as well as of the ability to establish asymmetry of exogenous lysophosphatidylserine. Rates of transbilayer reorientation of lysophospholipids for the vesicles, however, are comparable to those for intact cells. (4) Loss of endogenous asymmetry of phosphatidylserine is also observed in vesicles isolated from erythrocytes after heat denaturation of spectrin. The asymmetry in the residual cells is maintained. (5) In contrast to the loss of asymmetry of phosphatidylethanolamine and of phosphatidylserine, the asymmetry of sphingomyelin is completely maintained in the vesicles. (6) The stability of phospholipid asymmetry in the native cell is discussed in terms of a limitation of access of phospholipids to hypothetical reorientation sites. Such a limitation may either be the result of interaction of phospholipids with the membrane skeleton as in case of phosphatidylserine and phosphatidylethanolamine, or the result of lipid-lipid interactions as in case of sphingomyelin.

  12. 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…

  13. 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…

  14. Nodal signalling and asymmetry of the nervous system.

    PubMed

    Signore, Iskra A; Palma, Karina; Concha, Miguel L

    2016-12-19

    The role of Nodal signalling in nervous system asymmetry is still poorly understood. Here, we review and discuss how asymmetric Nodal signalling controls the ontogeny of nervous system asymmetry using a comparative developmental perspective. A detailed analysis of asymmetry in ascidians and fishes reveals a critical context-dependency of Nodal function and emphasizes that bilaterally paired and midline-unpaired structures/organs behave as different entities. We propose a conceptual framework to dissect the developmental function of Nodal as asymmetry inducer and laterality modulator in the nervous system, which can be used to study other types of body and visceral organ asymmetries. Using insights from developmental biology, we also present novel evolutionary hypotheses on how Nodal led the evolution of directional asymmetry in the brain, with a particular focus on the epithalamus. We intend this paper to provide a synthesis on how Nodal signalling controls left-right asymmetry of the nervous system.This article is part of the themed issue 'Provocative questions in left-right asymmetry'.

  15. 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.…

  16. Asymmetry of White Matter Pathways in Developing Human Brains.

    PubMed

    Song, Jae W; Mitchell, Paul D; Kolasinski, James; Ellen Grant, P; Galaburda, Albert M; Takahashi, Emi

    2015-09-01

    Little is known about the emergence of structural asymmetry of white matter tracts during early brain development. We examined whether and when asymmetry in diffusion parameters of limbic and association white matter pathways emerged in humans in 23 brains ranging from 15 gestational weeks (GW) up to 3 years of age (11 ex vivo and 12 in vivo cases) using high-angular resolution diffusion imaging tractography. Age-related development of laterality was not observed in a limbic connectional pathway (cingulum bundle or fornix). Among the studied cortico-cortical association pathways (inferior longitudinal fasciculus [ILF], inferior fronto-occipital fasciculus, and arcuate fasciculus), only the ILF showed development of age-related laterality emerging as early as the second trimester. Comparisons of ages older and younger than 40 GW revealed a leftward asymmetry in the cingulum bundle volume and a rightward asymmetry in apparent diffusion coefficient and leftward asymmetry in fractional anisotropy in the ILF in ages older than 40 GW. These results suggest that morphometric asymmetry in cortical areas precedes the emergence of white matter pathway asymmetry. Future correlative studies will investigate whether such asymmetry is anatomically/genetically driven or associated with functional stimulation.

  17. Interactions between white matter asymmetry and language during neurodevelopment.

    PubMed

    O'Muircheartaigh, Jonathan; Dean, Douglas C; Dirks, Holly; Waskiewicz, Nicole; Lehman, Katie; Jerskey, Beth A; Deoni, Sean C L

    2013-10-09

    The human brain is asymmetric in gross structure as well as functional organization. However, the developmental basis and trajectory of this asymmetry is unclear, and its relationship(s) to functional and cognitive development, especially language, remain to be fully elucidated. During infancy and early childhood, in concert with cortical gray matter growth, underlying axonal bundles become progressively myelinated. This myelination is critical for efficient and coherent interneuronal communication and, as revealed in animal studies, the degree of myelination changes in response to environment and neuronal activity. Using a novel quantitative magnetic resonance imaging method to investigate myelin content in vivo in human infants and young children, we investigated gross asymmetry of myelin in a large cohort of 108 typically developing children between 1 and 6 years of age, hypothesizing that asymmetry would predict language abilities in this cohort. While asymmetry of myelin content was evident in multiple cortical and subcortical regions, language ability was predicted only by leftward asymmetry of caudate and frontal cortex myelin content and rightward asymmetry in the extreme capsule. Importantly, the influence of this asymmetry was found to change with age, suggesting an age-specific influence of structure and myelin on language function. The relationship between language ability and asymmetry of myelin stabilized at ∼4 years, indicating anatomical evidence for a critical time during development before which environmental influence on cognition may be greatest.

  18. 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…

  19. 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…

  20. Mapping hemispheric symmetries, relative asymmetries, and absolute asymmetries underlying the auditory laterality effect.

    PubMed

    Westerhausen, René; Kompus, Kristiina; Hugdahl, Kenneth

    2014-01-01

    Functional hemispheric differences for speech and language processing have been traditionally studied by using verbal dichotic-listening paradigms. The commonly observed right-ear preference for the report of dichotically presented syllables is taken to reflect the left hemispheric dominance for speech processing. However, the results of recent functional imaging studies also show that both hemispheres - not only the left - are engaged by dichotic listening, suggesting a more complex relationship between behavioral laterality and functional hemispheric activation asymmetries. In order to more closely examine the hemispheric differences underlying dichotic-listening performance, we report an analysis of functional magnetic resonance imaging (fMRI) data of 104 right-handed subjects, for the first time combining an interhemispheric difference and conjunction analysis. This approach allowed for a distinction of homotopic brain regions which showed symmetrical (i.e., brain region significantly activated in both hemispheres and no activation difference between the hemispheres), relative asymmetrical (i.e., activated in both hemispheres but significantly stronger in one than the other hemisphere), and absolute asymmetrical activation patterns (i.e., activated only in one hemisphere and this activation is significantly stronger than in the other hemisphere). Symmetrical activation was found in large clusters encompassing temporal, parietal, inferior frontal, and medial superior frontal regions. Relative and absolute left-ward asymmetries were found in the posterior superior temporal gyrus, located adjacent to symmetrically activated areas, and creating a lateral-medial gradient from symmetrical towards absolute asymmetrical activation within the peri-Sylvian region. Absolute leftward asymmetry was also found in the post-central and medial superior frontal gyri, while rightward asymmetries were found in middle temporal and middle frontal gyri. We conclude that dichotic

  1. Reduced Spin Hall Effects from Magnetic Proximity.

    DOE PAGES

    Zhang, Wei; Jungfleisch, Matthias B.; Jiang, Wanjun; ...

    2015-03-26

    We investigate temperature-dependent spin pumping and inverse spin Hall effects in thin Pt and Pd in contact with Permalloy. Our experiments show a decrease of the spin Hall effect with decreasing temperature, which is attributed to a temperature-dependent proximity effect. The spin Hall angle decreases from 0.086 at room temperature to 0.042 at 10 K for Pt and is nearly negligible at 10 K for Pd. By first-principle calculations, we show that the spin Hall conductivity indeed reduces by increasing the proximity-induced spin magnetic moments for both Pt and Pd. This work highlights the important role of proximity-induced magnetic orderingmore » to spin Hall phenomena in Pt and Pd.« less

  2. Reduced Spin Hall Effects from Magnetic Proximity.

    SciTech Connect

    Zhang, Wei; Jungfleisch, Matthias B.; Jiang, Wanjun; Liu, Yaohua; Pearson, John E.; te Velthius, Suzanne G. E.; Hoffmann, Axel; Freimuth, Frank; Mokrousov, Yuri

    2015-03-26

    We investigate temperature-dependent spin pumping and inverse spin Hall effects in thin Pt and Pd in contact with Permalloy. Our experiments show a decrease of the spin Hall effect with decreasing temperature, which is attributed to a temperature-dependent proximity effect. The spin Hall angle decreases from 0.086 at room temperature to 0.042 at 10 K for Pt and is nearly negligible at 10 K for Pd. By first-principle calculations, we show that the spin Hall conductivity indeed reduces by increasing the proximity-induced spin magnetic moments for both Pt and Pd. This work highlights the important role of proximity-induced magnetic ordering to spin Hall phenomena in Pt and Pd.

  3. Evaluation and Management of Proximal Humerus Fractures

    PubMed Central

    Khmelnitskaya, Ekaterina; Lamont, Lauren E.; Taylor, Samuel A.; Lorich, Dean G.; Dines, David M.; Dines, Joshua S.

    2012-01-01

    Proximal humerus fractures are common injuries, especially among older osteoporotic women. Restoration of function requires a thorough understanding of the neurovascular, musculotendinous, and bony anatomy. This paper addresses the relevant anatomy and highlights various management options, including indication for arthroplasty. In the vast majority of cases, proximal humerus fractures may be treated nonoperatively. In the case of displaced fractures, when surgical intervention may be pursued, numerous constructs have been investigated. Of these, the proximal humerus locking plate is the most widely used. Arthroplasty is generally reserved for comminuted 4-part fractures, head-split fractures, or fractures with significant underlying arthritic changes. Reverse total shoulder arthroplasty is reserved for patients with a deficient rotator cuff, or highly comminuted tuberosities. PMID:23316376

  4. Two-Dimensional Optical Proximity Effects

    NASA Astrophysics Data System (ADS)

    Flanner, Philip D.; Subramanian, Shankar; Neureuther, Andrew R.

    1986-08-01

    In projection printing the proximity effects between adjacent two-dimensional features such as concentric elbows can be the limiting factor in designing layout rules. An aerial image simulation code based on the imaging algorithms in SAMPLE has been developed and used to investigate these proximity effects. The program accepts arbitrary polygonal shapes constructed of rectangular and triangular patches. The image is calculated using Hopkins transmission cross coefficient formulation and uses rapid integral evaluation techniques. The cpu time for this FORTRAN F77 program depends on the size of the mask and the partial coherence factor as 0.25[(1 + σ) 2A(NA/λ)2]2 seconds on a DEC VAX 11/780 using double precision, where A is the mask area, σ the coherence factor, NA the numerical aperture and λ the wavelength. The output intensity can be displayed with graphics tools such as UNIGRAFIX or cross-sectioned for input to SAMPLE development simulation along critical paths. Proximity effects in critical regions between features such as nested elbows, contacts near contacts and lines, and lines near large pads are studied. For small contacts studies show that a contact hole can be placed as close as 0.5λ/NA microns to another contact hole. For nested elbows the critical effect is the variation in intensity in the straight regions just adjacent to the corner. This undesirable variation is primarily due to the intrafeature intensity interactions and is not greatly influenced by the proximity of another nested elbow. For general feature shapes the proximity effects are reduced by increasing the partial coherence factor to 0.5 or higher but at the cost of reducing contrast and peak intensity. For contact masks a partial coherence of 0.3 is recommended for higher edge slope and peak intensities. Proximity effects of small defects are also illustrated.

  5. [Partial replantation following proximal limb injury].

    PubMed

    Dubert, T; Malikov, S A; Dinh, A; Kupatadze, D D; Oberlin, C; Alnot, J Y; Nabokov, B B

    2000-11-01

    Proximal replantation is a technically feasible but life-threatening procedure. Indications must be restricted to patients in good condition with a good functional prognosis. The goal of replantation must be focused not only on reimplanting the amputated limb but also on achieving a good functional outcome. For the lower limb, simple terminalization remains the best choice in many cases. When a proximal amputation is not suitable for replantation, the main aim of the surgical procedure must be to reconstruct a stump long enough to permit fitting a prosthesis preserving the function of the adjacent joint. If the proximal stump beyond the last joint is very short, it may be possible to restore some length by partial replantation of spared tissues from the amputated part. We present here the results we obtained following this policy. This series included 16 cases of partial replantations, 14 involving the lower limb and 2 the upper limb. All were osteocutaneous microsurgical transfers. For the lower limb, all transfers recovered protective sensitivity following tibial nerve repair. The functional calcaeoplantar unit was used in 13 cases. The transfer of this specialized weight bearing tissue provided a stable distal surface making higher support unnecessary. In one case, we raised a 13-cm vascularized tibial segment covered with foot skin for additional length. For the upper limb, the osteocutaneous transfer, based on the radial artery, was not reinnervated, but this lack of sensitivity did not impair prosthesis fitting. One vascular failure was finally amputated. This was the only unsuccessful result. For all other patients, the surgical procedure facilitated prosthesis fitting and preserved the proximal joint function despite an initially very proximal amputation. The advantages of partial replantation are obvious compared with simple terminalization or secondary reconstruction. There is no secondary donor site and, because there is no major muscle mass in the

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

    DOE PAGES

    Metz, Andreas; Pitonyak, Daniel; Schafer, Andreas; ...

    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

  7. Fluctuating odontometric asymmetry in the Lengua Indians of Paraguay.

    PubMed

    Kieser, J A; Groeneveld, H T; Preston, C B

    1986-01-01

    Fluctuating dental asymmetry was evaluated as an indicator of environmental stress in a group of 202 living Lengua Indians from the Paraguayan Chaco area. Older, less accultured individuals were shown to be significantly more asymmetric than younger individuals who had been increasingly exposed to western foodstuffs and medicine. Lengua Indians demonstrated similar levels of asymmetry to another preliterate group, the Ticuna Indians of Columbia, but were found to be significantly more asymmetric than contemporary caucasoids. Similar patterns of asymmetry in both arcades for males and females were confirmed by analyses of variance and by Spearman's rank-order correlation coefficients. Partitioning variation in the degree of asymmetry by arcade, dimension and tooth revealed significant differences in the effects of tooth and arcade only: asymmetry was greater in the maxilla and greater in the more distal teeth within each morphogenic class.

  8. 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.

  9. 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.

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

    NASA Astrophysics Data System (ADS)

    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.; Åsman, 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.; Besançon, 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-Pérez, E.; Carrasco-Lizarraga, M. A.; Casey, B. C. K.; Castilla-Valdez, H.; Chakrabarti, S.; Chakraborty, D.; Chan, K. M.; Chandra, A.; Chen, G.; Chevalier-Théry, 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.; Déliot, 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.; Grünendahl, S.; Grünewald, 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.; Jaffré, 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.; Kurča, 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.; Lopes de Sa, R.; Lubatti, H. J.; Luna-Garcia, R.; Lyon, A. L.; Maciel, A. K. A.; Mackin, D.; Madar, R.; Magaña-Villalba, R.; Malik, S.; Malyshev, V. L.; Maravin, Y.; Martínez-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.; Otero Y Garzón, G. J.; Padilla, M.; Pal, A.; Parashar, N.; Parihar, V.; Park, S. K.; Parsons, J.; Partridge, R.; Parua, N.; Patwa, A.; Penning, B.; Perfilov, M.; Peters, K.; Peters, Y.; Petridis, K.; Petrillo, G.; Pétroff, P.; Piegaia, R.; Pleier, M.-A.; Podesta-Lerma, P. L. M.; Podstavkov, V. M.; Polozov, P.; Popov, A. V.; Prewitt, M.; Price, D.; Prokopenko, N.; Protopopescu, S.; Qian, J.; Quadt, A.; Quinn, B.; Rangel, M. S.; Ranjan, K.; Ratoff, P. N.; Razumov, I.; Renkel, P.; Rijssenbeek, M.; Ripp-Baudot, I.; Rizatdinova, F.; Rominsky, M.; Ross, A.; Royon, C.; Rubinov, P.; Ruchti, R.; Safronov, G.; Sajot, G.; Salcido, P.; Sánchez-Hernández, A.; Sanders, M. P.; Sanghi, B.; Santos, A. S.; Savage, G.; Sawyer, L.; Scanlon, T.; Schamberger, R. D.; Scheglov, Y.; Schellman, H.; Schliephake, T.; Schlobohm, S.; Schwanenberger, C.; Schwienhorst, R.; Sekaric, J.; Severini, H.; Shabalina, E.; Shary, V.; Shchukin, A. A.; Shivpuri, R. K.; Simak, V.; Sirotenko, V.; Skubic, P.; Slattery, P.; Smirnov, D.; Smith, K. J.; Snow, G. R.; Snow, J.; Snyder, S.; Söldner-Rembold, S.; Sonnenschein, L.; Soustruznik, K.; Stark, J.; Stolin, V.; Stoyanova, D. A.; Strauss, M.; Strom, D.; Stutte, L.; Suter, L.; Svoisky, P.; Takahashi, M.; Tanasijczuk, A.; Taylor, W.; Titov, M.; Tokmenin, V. V.; Tsai, Y.-T.; Tsybychev, D.; Tuchming, B.; Tully, C.; Uvarov, L.; Uvarov, S.; Uzunyan, S.; van Kooten, R.; van Leeuwen, W. M.; Varelas, N.; Varnes, E. W.; Vasilyev, I. A.; Verdier, P.; Vertogradov, L. S.; Verzocchi, M.; Vesterinen, M.; Vilanova, D.; Vokac, P.; Wahl, H. D.; Wang, M. H. L. S.; Warchol, J.; Watts, G.; Wayne, M.; Weber, M.; Welty-Rieger, L.; White, A.; Wicke, D.; Williams, M. R. J.; Wilson, G. W.; Wobisch, M.; Wood, D. R.; Wyatt, T. R.; Xie, Y.; Xu, C.; Yacoob, S.; Yamada, R.; Yang, W.-C.; Yasuda, T.; Yatsunenko, Y. A.; Ye, Z.; Yin, H.; Yip, K.; Youn, S. W.; Yu, J.; Zelitch, S.; Zhao, T.; Zhou, B.; Zhu, J.; Zielinski, M.; Zieminska, D.; Zivkovic, L.

    2011-12-01

    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 5.4fb-1, collected by the D0 experiment at the Fermilab Tevatron Collider, we measure the tt¯ 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.

  11. Ultimate and proximate explanations of strong reciprocity.

    PubMed

    Vromen, Jack

    2017-08-23

    Strong reciprocity (SR) has recently been subject to heated debate. In this debate, the "West camp" (West et al. in Evol Hum Behav 32(4):231-262, 2011), which is critical of the case for SR, and the "Laland camp" (Laland et al. in Science, 334(6062):1512-1516, 2011, Biol Philos 28(5):719-745, 2013), which is sympathetic to the case of SR, seem to take diametrically opposed positions. The West camp criticizes advocates of SR for conflating proximate and ultimate causation. SR is said to be a proximate mechanism that is put forward by its advocates as an ultimate explanation of human cooperation. The West camp thus accuses advocates of SR for not heeding Mayr's original distinction between ultimate and proximate causation. The Laland camp praises advocates of SR for revising Mayr's distinction. Advocates of SR are said to replace Mayr's uni-directional view on the relation between ultimate and proximate causes by the bi-directional one of reciprocal causation. The paper argues that both the West camp and the Laland camp misrepresent what advocates of SR are up to. The West camp is right that SR is a proximate cause of human cooperation. But rather than putting forward SR as an ultimate explanation, as the West camp argues, advocates of SR believe that SR itself is in need of ultimate explanation. Advocates of SR tend to take gene-culture co-evolutionary theory as the correct meta-theoretical framework for advancing ultimate explanations of SR. Appearances notwithstanding, gene-culture coevolutionary theory does not imply Laland et al.'s notion of reciprocal causation. "Reciprocal causation" suggests that proximate and ultimate causes interact simultaneously, while advocates of SR assume that they interact sequentially. I end by arguing that the best way to understand the debate is by disambiguating Mayr's ultimate-proximate distinction. I propose to reserve "ultimate" and "proximate" for different sorts of explanations, and to use other terms for distinguishing

  12. Predictive risk models for proximal aortic surgery

    PubMed Central

    Díaz, Rocío; Pascual, Isaac; Álvarez, Rubén; Alperi, Alberto; Rozado, Jose; Morales, Carlos; Silva, Jacobo; Morís, César

    2017-01-01

    Predictive risk models help improve decision making, information to our patients and quality control comparing results between surgeons and between institutions. The use of these models promotes competitiveness and led to increasingly better results. All these virtues are of utmost importance when the surgical operation entails high-risk. Although proximal aortic surgery is less frequent than other cardiac surgery operations, this procedure itself is more challenging and technically demanding than other common cardiac surgery techniques. The aim of this study is to review the current status of predictive risk models for patients who undergo proximal aortic surgery, which means aortic root replacement, supracoronary ascending aortic replacement or aortic arch surgery. PMID:28616348

  13. Predictive risk models for proximal aortic surgery.

    PubMed

    Hernandez-Vaquero, Daniel; Díaz, Rocío; Pascual, Isaac; Álvarez, Rubén; Alperi, Alberto; Rozado, Jose; Morales, Carlos; Silva, Jacobo; Morís, César

    2017-05-01

    Predictive risk models help improve decision making, information to our patients and quality control comparing results between surgeons and between institutions. The use of these models promotes competitiveness and led to increasingly better results. All these virtues are of utmost importance when the surgical operation entails high-risk. Although proximal aortic surgery is less frequent than other cardiac surgery operations, this procedure itself is more challenging and technically demanding than other common cardiac surgery techniques. The aim of this study is to review the current status of predictive risk models for patients who undergo proximal aortic surgery, which means aortic root replacement, supracoronary ascending aortic replacement or aortic arch surgery.

  14. Strategy for photostable proximity bioassays using lanthanides

    PubMed Central

    Haushalter, Jeanne P.; Faris, Gregory W.

    2011-01-01

    We report initial findings for research aimed at creating photostable lanthanide chelate reporters for proximity assays. These reporters take advantage of the nanometer scale distance dependence of fluorescence enhancement for molecules in the vicinity of noble metal nanoparticles and also capitalize on some unique properties of lanthanide chelates. This approach promises to lead to proximity assays that do not suffer from photobleaching and offer very high on/off enhancement ratios. Results for lanthanide chelates on silver island films and in colloidal suspensions are reported. Enhancement factors range from 1 to 2 orders of magnitude, with larger enhancements for strongly quenched lanthanides. PMID:17356638

  15. Infrared-Proximity-Sensor Modules For Robot

    NASA Technical Reports Server (NTRS)

    Parton, William; Wegerif, Daniel; Rosinski, Douglas

    1995-01-01

    Collision-avoidance system for articulated robot manipulators uses infrared proximity sensors grouped together in array of sensor modules. Sensor modules, called "sensorCells," distributed processing board-level products for acquiring data from proximity-sensors strategically mounted on robot manipulators. Each sensorCell self-contained and consists of multiple sensing elements, discrete electronics, microcontroller and communications components. Modules connected to central control computer by redundant serial digital communication subsystem including both serial and a multi-drop bus. Detects objects made of various materials at distance of up to 50 cm. For some materials, such as thermal protection system tiles, detection range reduced to approximately 20 cm.

  16. Dark atoms: asymmetry and direct detection

    SciTech Connect

    Kaplan, David E.; Krnjaic, Gordan Z.; Rehermann, Keith R.; Wells, Christopher M. E-mail: gordan@pha.jhu.edu E-mail: christopher.wells@houghton.edu

    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 unrecombined dark ions settle into a diffuse isothermal halo.

  17. 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.

  18. Lepton asymmetry and neutrino oscillations interplay

    NASA Astrophysics Data System (ADS)

    Kirilova, Daniela

    2013-03-01

    We discuss the interplay between lepton asymmetry L and ν oscillations in the early Universe. Neutrino oscillations may suppress or enhance previously existing L. On the other hand L is capable to suppress or enhance neutrino oscillations. The mechanism of L enhancement in MSW resonant ν oscillations in the early Universe is numerically analyzed. L cosmological effects through ν oscillations are discussed. We discuss how L may change the cosmological BBN constraints on neutrino and show that BBN model with ν_e leftrightarrow ν_s oscillations is extremely sensitive to L - it allows to obtain the most stringent constraints on L value. We discuss also the cosmological role of active-sterile ν mixing and L in connection with the indications about additional relativistic density in the early Universe, pointed out by BBN, CMB and LSS data and the analysis of global ν data.

  19. Inter-hemispheric asymmetries in Saturn's aurora

    NASA Astrophysics Data System (ADS)

    Badman, Sarah; Lamy, Laurent; Bunce, Emma; Cecconi, Baptiste; Clarke, John; Crary, Frank; Dougherty, Michele; Dyudina, Ulyana; Kinrade, Joe; Kurth, Bill; Melin, Henrik; Mitchell, Don; Nichols, Jonathan; Prange, Renee; Pryor, Wayne; Radioti, Katerina; Schippers, Patricia; Zarka, Philippe

    2017-04-01

    During two intervals in 2016 Saturn's UV aurorae were observed simultaneously in the northern, summer hemisphere by the Hubble Space Telescope and the southern, winter hemisphere by Cassini. For the first time the full auroral region was visible in both hemispheres allowing the nightside auroral morphology to be examined as well as the dayside. We find significant differences in the relative auroral intensities between the two hemispheres, particularly in the most poleward arcs observed under more active magnetospheric conditions. We propose that these asymmetries could be driven by inter-hemispheric field-aligned currents, or, considering the high latitude extent of some features, in association with enhanced auroral precipitation on newly-reconnected field lines. In the latter scenario, the lifetime of the high latitude auroral feature suggests that enhanced precipitation persists for at least 4 hours, longer than previously estimated, as the arc rotates to the nightside.

  20. Asymmetry-induced synchronization in oscillator networks

    NASA Astrophysics Data System (ADS)

    Zhang, Yuanzhao; Nishikawa, Takashi; Motter, Adilson E.

    2017-06-01

    A scenario has recently been reported in which in order to stabilize complete synchronization of an oscillator network—a symmetric state—the symmetry of the system itself has to be broken by making the oscillators nonidentical. But how often does such behavior—which we term asymmetry-induced synchronization (AISync)—occur in oscillator networks? Here we present the first general scheme for constructing AISync systems and demonstrate that this behavior is the norm rather than the exception in a wide class of physical systems that can be seen as multilayer networks. Since a symmetric network in complete synchrony is the basic building block of cluster synchronization in more general networks, AISync should be common also in facilitating cluster synchronization by breaking the symmetry of the cluster subnetworks.

  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. 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.

  3. Leptophilic Dark Matter from the Lepton Asymmetry

    NASA Astrophysics Data System (ADS)

    Cohen, Timothy; Zurek, Kathryn M.

    2010-03-01

    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.

  4. 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.

  5. Giver-receiver asymmetries in gift preferences.

    PubMed

    Teigen, Karl Halvor; Olsen, Marina V G; Solås, Odd Egil

    2005-03-01

    When people are asked to choose between gift items, givers and receivers sometimes show different patterns of preferences. The article reports four experimental studies exploring these giver-receiver asymmetries. Whereas givers tend to prefer exclusive, but smaller gift items, receivers appear to prefer less luxurious, and more useful gifts (Experiment 1). Givers prefer gift vouchers to cash, and are concerned about timing, whereas more receivers accept cash gifts, and claim that it does not matter if the gift arrives late (Experiment 2). One interpretation of the results could be that givers conform more strongly to gift conventions (cultural norms for gift exchange). It is further argued that these differences are not due to a perceived difference between self and others (Experiment 3), but rather because of situational differences. When receivers perform separate evaluations of gifts rather than joint evaluations (pairwise comparisons), they tend to change their preference pattern towards a higher rating of exclusive gift items (Experiment 4).

  6. Mathematical Modeling of Sub-Cellular Asymmetry of Fat-Dachsous Heterodimer for Generation of Planar Cell Polarity

    PubMed Central

    Kumar, Amit; Sinha, Pradip

    2014-01-01

    Planar Cell Polarity (PCP) is an evolutionarily conserved characteristic of animal tissues marked by coordinated polarization of cells or structures in the plane of a tissue. In insect wing epithelium, for instance, PCP is characterized by en masse orientation of hairs orthogonal to its apical-basal axis and pointing along the proximal-distal axis of the organ. Directional cue for PCP has been proposed to be generated by complex sets of interactions amongst three proteins - Fat (Ft), Dachsous (Ds) and Four-jointed (Fj). Ft and Ds are two atypical cadherins, which are phosphorylated by Fj, a Golgi kinase. Ft and Ds from adjacent cells bind heterophilically via their tandem cadherin repeats, and their binding affinities are regulated by Fj. Further, in the wing epithelium, sub-cellular levels of Ft-Ds heterodimers are seen to be elevated at the distal edges of individual cells, prefiguring their PCP. Mechanisms generating this sub-cellular asymmetry of Ft-Ds heterodimer in proximal and distal edges of cells, however, have not been resolved yet. Using a mathematical modeling approach, here we provide a framework for generation of this sub-cellular asymmetry of Ft-Ds heterodimer. First, we explain how the known interactions within Ft-Ds-Fj system translate into sub-cellular asymmetry of Ft-Ds heterodimer. Second, we show that this asymmetric localization of Ft-Ds heterodimer is lost when tissue-level gradient of Fj is flattened, or when phosphorylation of Ft by Fj is abolished, but not when tissue-level gradient of Ds is flattened or when phosphorylation of Ds is abrogated. Finally, we show that distal enrichment of Ds also amplifies Ft-Ds asymmetry. These observations reveal that gradient of Fj expression, phosphorylation of Ft by Fj and sub-cellular distal accumulation of Ds are three critical elements required for generating sub-cellular asymmetry of Ft-Ds heterodimer. Our model integrates the known experimental data and presents testable predictions for future

  7. Proximal femoral focal deficiency of the fetus - early 3D/4D prenatal ultrasound diagnosis.

    PubMed

    Kudla, Marek J; Beczkowska-Kielek, Aleksandra; Kutta, Katarzyna; Partyka-Lasota, Justyna

    2016-09-01

    Proximal Femoral Focal Deficiency (PFFD) is a rare congenital syndrome of unknown etiology. Additional disorders can be present up to 70% of PFFD cases. Management (including termination) depends on the severity of the malformation. We present a case of a 32-year-old woman referred for routine ultrasound examination in the 12th week of pregnancy. Detailed 3D/4D evaluation revealed asymmetry of lower limbs and diagnosis of isolated PFFD was established. Parents were fully informed and decided to continue the pregnancy. We stress here the importance of early 3D/4D ultrasound diagnosis. Our paper presents the earliest case where the diagnosis of PFFD was established with 3D/4D ultrasound.

  8. Goal-Proximity Decision-Making

    ERIC Educational Resources Information Center

    Veksler, Vladislav D.; Gray, Wayne D.; Schoelles, Michael J.

    2013-01-01

    Reinforcement learning (RL) models of decision-making cannot account for human decisions in the absence of prior reward or punishment. We propose a mechanism for choosing among available options based on goal-option association strengths, where association strengths between objects represent previously experienced object proximity. The proposed…

  9. The Zone of Proximal "Teacher" Development

    ERIC Educational Resources Information Center

    Warford, Mark K.

    2011-01-01

    Toward the end of his short life, Lev Vygotsky found himself teaching teachers in a remote part of the USSR. Though his influence as a developmental psychologist is well-established, little is known about his approach to teacher development. This article applies the researcher's core concept, the zone of proximal development to teacher education.…

  10. Dynamic treatment of displaced proximal phalangeal fractures.

    PubMed

    Ebinger, T; Erhard, N; Kinzl, L; Mentzel, M

    1999-11-01

    We report a splint system for a protected mobilization program (termed dynamic treatment) of proximal phalangeal fractures. This program can be used for nonoperative treatment or after operative treatment. Intra-articular fractures of the proximal phalanx at the metacarpophalangeal joint were included. The custom-molded 2-component thermoplastic splint allows motion of the proximal and distal interphalangeal joints. It was developed to allow bone healing and recovery of motion at the same time. We evaluated the clinical and radiologic results of a consecutive series of 48 displaced proximal phalangeal fractures in 45 patients who received dynamic treatment. Fracture consolidation was achieved in all patients and bone healing and recovery of full active motion was achieved simultaneously in all but 4 patients by 6 weeks. The advantage of this splint system is the variability of its application. The splint can be used both for nonsurgical and surgical management. It can be removed to change dressings and for radiologic evaluations. The period of dynamic treatment can be determined individually in each case.

  11. Current status of proximal gastric vagotomy.

    PubMed Central

    Schirmer, B D

    1989-01-01

    Proximal gastric vagotomy is nearing its twentieth year in clinical use as an operation for peptic ulcer disease. No other acid-reducing operation has undergone as much scrutiny or study. At this time, the evidence of such studies and long-term follow-up strongly supports the use of proximal gastric vagotomy as the treatment of choice for chronic duodenal ulcer in patients who have failed medical therapy. Its application in treating the complications of peptic ulcer disease, which recently have come to represent an increasingly greater percentage of all operations done for peptic ulcer disease, is well-tested. However, initial series suggest that it should probably occupy a prominent role in treating some of these complications, particularly in selected patients, in the future. The operation has the well-documented ability to reduce gastric acid production, not inhibit gastric bicarbonate production, and also minimally inhibit gastric motility. The combination of these physiologic results after proximal gastric vagotomy, along with preservation of the normal antropyloroduodenal mechanism of gastrointestinal control, serve to allow patients with proximal gastric vagotomy the improved benefits of significantly fewer severe gastrointestinal side effects than are seen after other operations for peptic ulcer disease. PMID:2644897

  12. Object detection system using SPAD proximity detectors

    NASA Astrophysics Data System (ADS)

    Stark, Laurence; Raynor, Jeffrey M.; Henderson, Robert K.

    2011-10-01

    This paper presents an object detection system based upon the use of multiple single photon avalanche diode (SPAD) proximity sensors operating upon the time-of-flight (ToF) principle, whereby the co-ordinates of a target object in a coordinate system relative to the assembly are calculated. The system is similar to a touch screen system in form and operation except that the lack of requirement of a physical sensing surface provides a novel advantage over most existing touch screen technologies. The sensors are controlled by FPGA-based firmware and each proximity sensor in the system measures the range from the sensor to the target object. A software algorithm is implemented to calculate the x-y coordinates of the target object based on the distance measurements from at least two separate sensors and the known relative positions of these sensors. Existing proximity sensors were capable of determining the distance to an object with centimetric accuracy and were modified to obtain a wide field of view in the x-y axes with low beam angle in z in order to provide a detection area as large as possible. Design and implementation of the firmware, electronic hardware, mechanics and optics are covered in the paper. Possible future work would include characterisation with alternative designs of proximity sensors, as this is the component which determines the highest achievable accur1acy of the system.

  13. Encoding Direction when Interpreting Proximal Terms

    ERIC Educational Resources Information Center

    Ashley, Aaron; Carlson, Laura A.

    2007-01-01

    The location of an object is often described by spatially relating it to a known landmark. The spatial terms used in such descriptions can provide various types of information. For example, projective terms such as "above" indicate direction but not distance, whereas proximal terms such as "near" indicate distance but not direction. Previous…

  14. Email Keypals in Zone of Proximal Development.

    ERIC Educational Resources Information Center

    Kaufman, Lionel M., Jr.

    This study analyzed the discourse of electronic mail (e-mail) exchanges between students of English as a second language (ESL) and other ESL learners from other cultures and at varying proficiency levels (keypals), focusing on what these exchanges may reveal about learners' progress through the "Zone of Proximal Development," a…

  15. [Proximity and breastfeeding at the maternity hospital].

    PubMed

    Fradin-Charrier, Anne-Claire

    2015-01-01

    The establishment of breastfeeding, as well as its duration, are facilitated through the proximity of the mother with her new baby. However, in maternity hospitals, breastfeeding mothers very often leave their baby in the nursery at night time. A study carried out in 2014 in several maternity hospitals put forward suggestions and highlighted areas to improve in everyday practice.

  16. Vortices in normal part of proximity system

    DOE PAGES

    Kogan, V. G.

    2015-05-26

    It is shown that the order parameter Δ induced in the normal part of superconductor-normal-superconductor proximity system is modulated in the magnetic field differently from vortices in bulk superconductors. Whereas Δ turns zero at vortex centers, the magnetic structure of these vortices differs from that of Abrikosov's.

  17. Recreation in urban-proximate natural areas

    Treesearch

    P.L. Winter; D.J. Chavez

    1999-01-01

    Recreation in urban proximate wildland and wilderness areas and resulting management concerns and challenges have proven a fertile ground for social science research. As the demand for recreation opportunities adjacent to large urban centers has increased, so has the variety of recreational interests, patterns, and preferences, a reflection of the diverse...

  18. Encoding Direction when Interpreting Proximal Terms

    ERIC Educational Resources Information Center

    Ashley, Aaron; Carlson, Laura A.

    2007-01-01

    The location of an object is often described by spatially relating it to a known landmark. The spatial terms used in such descriptions can provide various types of information. For example, projective terms such as "above" indicate direction but not distance, whereas proximal terms such as "near" indicate distance but not direction. Previous…

  19. Vortices in normal part of proximity system

    SciTech Connect

    Kogan, V. G.

    2015-05-26

    It is shown that the order parameter Δ induced in the normal part of superconductor-normal-superconductor proximity system is modulated in the magnetic field differently from vortices in bulk superconductors. Whereas Δ turns zero at vortex centers, the magnetic structure of these vortices differs from that of Abrikosov's.

  20. Goal-Proximity Decision-Making

    ERIC Educational Resources Information Center

    Veksler, Vladislav D.; Gray, Wayne D.; Schoelles, Michael J.

    2013-01-01

    Reinforcement learning (RL) models of decision-making cannot account for human decisions in the absence of prior reward or punishment. We propose a mechanism for choosing among available options based on goal-option association strengths, where association strengths between objects represent previously experienced object proximity. The proposed…

  1. Laparoscopic Proximal Gastrectomy With Gastric Tube Reconstruction

    PubMed Central

    Shiraishi, Norio; Toujigamori, Manabu; Shiroshita, Hidefumi; Etoh, Tsuyoshi; Inomata, Masafumi

    2016-01-01

    Background and Objectives: There is no standardized method of reconstruction in laparoscopic proximal gastrectomy (LPG). We present a novel technique of reconstruction with a long, narrow gastric tube in LPG for early gastric cancer (EGC). Methods: During the laparoscopic procedure, the upper part of the stomach is fully mobilized with perigastric and suprapancreatic lymphadenectomy, and then the abdominal esophagus is transected. After a minilaparotomy is created, the entire stomach is pulled outside. A long, narrow gastric tube (20 cm long, 3 cm wide) is created with a linear stapler. The proximal part of the gastric tube is formed into a cobra head shape for esophagogastric tube anastomosis, which is then performed with a 45-mm linear stapler under laparoscopic view. The end of the esophagus is fixed on the gastric tube to prevent postoperative esophageal reflux. Results: Thirteen patients with early proximal gastric cancer underwent the procedure. The mean operative time was 283 min, and median blood loss was 63 ml. There were no conversions to open surgery, and no intraoperative complications. Conclusion: This new technique of reconstruction after LPG is simple and feasible. The procedure has the potential of becoming a standard reconstruction technique after LPG for proximal EGC. PMID:27547027

  2. Proximity correction for electron beam lithography

    NASA Astrophysics Data System (ADS)

    Marrian, Christie R.; Chang, Steven; Peckerar, Martin C.

    1996-09-01

    As the critical dimensions required in mask making and direct write by electron beam lithography become ever smaller, correction for proximity effects becomes increasingly important. Furthermore, the problem is beset by the fact that only a positive energy dose can be applied with an electron beam. We discuss techniques such as chopping and dose shifting, which have been proposed to meet the positivity requirement. An alternative approach is to treat proximity correction as an optimization problem. Two such methods, local area dose correction and optimization using a regularizer proportional to the informational entropy of the solution, are compared. A notable feature of the regularized proximity correction is the ability to correct for forward scattering by the generation of a 'firewall' set back from the edge of a feature. As the forward scattering width increases, the firewall is set back farther from the feature edge. The regularized optimization algorithm is computationally time consuming using conventional techniques. However, the algorithm lends itself to a microelectronics integrated circuit coprocessor implementation, which could perform the optimization faster than even the fastest work stations. Scaling the circuit to larger number of pixels is best approached with a hybrid serial/parallel digital architecture that would correct for proximity effects over 108 pixels in about 1 h. This time can be reduced by simply adding additional coprocessors.

  3. Proximity correction for e-beam lithography

    NASA Astrophysics Data System (ADS)

    Marrian, Christie R.; Chang, Steven; Peckerar, Martin C.

    1995-12-01

    As the critical dimensions required for masks and e-beam direct write become ever smaller, the correction of proximity effects becomes more necessary. Furthermore, the problem is beset by the fact that only a positive energy dose can be applied with the e-beam. We discuss here approaches such as chopping and dose shifting which have been proposed to meet the positivity requirement. An alternative approach is to treat proximity correction as an optimization problem. Two such methods, local area dose correction and optimization using a regularizer proportional to the informational entropy of the solution, are compared. A notable feature of the regularized proximity correction is the ability to correct for forward scattering by the generation of a 'firewall' set back from the edge of a feature. As the forward scattering width increases, the firewall is set back further from the feature edge. The regularized optimization algorithm is computationally time consuming using conventional techniques. However, the algorithm lends itself to a microelectronics integrated circuit coprocessor implementation which could perform the optimization much faster than even the fastest work stations. Scaling the circuit to larger number of pixels is best approached with a hybrid serial/parallel digital architecture which would correct for proximity effects over 108 pixels about one hour. This time can be reduced by simply adding additional coprocessors.

  4. Reduced auditory M100 asymmetry in schizophrenia and dyslexia: applying a developmental instability approach to assess atypical brain asymmetry.

    PubMed

    Edgar, J Christopher; Yeo, Ron A; Gangestad, Steven W; Blake, Melissa B; Davis, John T; Lewine, Jeffrey D; Cañive, José M

    2006-01-01

    Although atypical structural and functional superior temporal gyrus (STG) asymmetries are frequently observed in patients with schizophrenia and individuals with dyslexia, their significance is unclear. One possibility is that atypical asymmetries reflect a general risk factor that can be seen across multiple neurodevelopmental conditions--a risk factor whose origins are best understood in the context of Developmental Instability (DI) theory. DI measures (minor physical anomalies (MPAs) and fluctuating asymmetries (FAs)) reflect perturbation of the genetic plan. The present study sought to assess whether the presence of peripheral indices of DI predicts anomalous functional auditory cortex asymmetry in schizophrenia patients and dyslexia subjects. The location of the auditory M100 response was used as a measure of functional STG asymmetry, as it has been reported that in controls (but not in subjects with schizophrenia or dyslexia) the M100 source location in the right hemisphere is shifted anterior to that seen for the left hemisphere. Whole-brain auditory evoked magnetic field data were successfully recorded from 14 male schizophrenia patients, 21 male subjects with dyslexia, and 16 normal male control subjects. MPA and FA measures were also obtained. Replicating previous studies, both schizophrenia and dyslexia groups showed less M100 asymmetry than did controls. Schizophrenia and dyslexia subjects also had higher MPA scores than normal controls. Although neither total MPA nor FA measures predicted M100 asymmetry, analyses on individual MPA items revealed a relationship between high palate and M100 asymmetry. Findings suggest that M100 positional asymmetry is not a diagnostically specific feature in several neurodevelopmental conditions. Continued research examining DI and brain asymmetry relationships is warranted.

  5. The asymmetry of the carpal joint and the evolution of wing folding in maniraptoran theropod dinosaurs.

    PubMed

    Sullivan, Corwin; Hone, David W E; Xu, Xing; Zhang, Fucheng

    2010-07-07

    In extant birds, the hand is permanently abducted towards the ulna, and the wrist joint can bend extensively in this direction to fold the wing when not in use. Anatomically, this asymmetric mobility of the wrist results from the wedge-like shape of one carpal bone, the radiale, and from the well-developed convexity of the trochlea at the proximal end of the carpometacarpus. Among the theropod precursors of birds, a strongly convex trochlea is characteristic of Coelurosauria, a clade including the highly derived Maniraptora in addition to tyrannosaurs and compsognathids. The shape of the radiale can be quantified using a 'radiale angle' between the proximal and distal articular surfaces. Measurement of the radiale angle and reconstruction of ancestral states using squared-change parsimony shows that the angle was small (15 degrees) in primitive coelurosaurs but considerably larger (25 degrees) in primitive maniraptorans, indicating that the radiale was more wedge-shaped and the carpal joint more asymmetric. The radiale angle progressively increased still further within Maniraptora, with concurrent elongation of the forelimb feathers and the forelimb itself. Carpal asymmetry would have permitted avian-like folding of the forelimb in order to protect the plumage, an early advantage of the flexible, asymmetric wrist inherited by birds.

  6. Factors affecting proximal tubular reabsorption during development

    SciTech Connect

    Kaskel, F.J.; Kumar, A.M.; Lockhart, E.A.; Evan, A.; Spitzer, A.

    1987-01-01

    Studies performed in several animal species have demonstrated that glomerulotubular balance is maintained throughout development despite the many changes that occur in the factors known to control it. In an attempt to understand the nature of this phenomenon the authors quantified the magnitude and described the profile of these changes in guinea pigs. The changes in physical forces were assessed from measurements of hydrostatic and oncotic pressures, whereas those in the permeability characteristics of the proximal tubule epithelium were estimated from permanence to radioactivity-labelled macromolecules of graded radii, histologic measurements of the intercellular channels, and measurements of end-proximal ratio of tubular fluid-to-plasma osmolality (TF/P/sub osm/). Between 1 and 50 days of age the net pressure for reabsorption increased from 15.0 to 30.9 mmHg with the major change occurring during the first 2-3 wk of postnatal life. The urinary recovery of (/sup 3/H)inulin, (/sup 14/C)sucrose, and (/sup 14/C)creatinine, injected in the early segment of proximal tubules did not vary with age. The urinary recovery of (/sup 14/C)mannitol increased from 92% at birth to 100% at 49 days of age. The length of the zonulae occludens and the width of the intercellular channels did not change during this period. The findings support the hypothesis that during early postnatal life glomerulotubular balance is made possible by a high permeability of the proximal tubule, which compensates for the low net reabsorptive pressure. As the animal matures and the proximal tubule epithelium becomes tighter, for glomerulotubular balance to be maintained, an increase in the number of intercellular channels and in the active transport of sodium need to be postulated.

  7. Characteristics of He II Proximity Profiles

    NASA Astrophysics Data System (ADS)

    Zheng, Wei; Syphers, David; Meiksin, Avery; Kriss, Gerard A.; Schneider, Donald P.; York, Donald G.; Anderson, Scott F.

    2015-06-01

    The proximity profile in the spectra of z≈ 3 quasars, where fluxes extend blueward of the He ii Lyα wavelength 304 (1+z) Å, is one of the most important spectral features in the study of the intergalactic medium (IGM). Based on the Hubble Space Telescope spectra of 24 He ii quasars, we find that the majority of them display a proximity profile, corresponding to an ionization radius as large as 20 Mpc in the source's rest frame. In comparison with those in the H i spectra of the quasars at z ≈ 6, the He ii proximity effect is more prominent and is observed over a considerably longer period of reionization. The He ii proximity zone sizes decrease at higher redshifts, particularly at z\\gt 3.3. This trend is similar to that for H i, signaling an onset of He ii reionization at z≳ 4. For quasar SDSS1253+6817 (z = 3.48), the He ii absorption trough displays a gradual decline and serves as a good case for modeling the He ii reionization. To model such a broad profile requires a quasar radiation field whose energy distribution between 4 and 1 Rydberg is considerably harder than normally assumed. The UV continuum of this quasar is indeed exceptionally steep, and the He ii ionization level in the quasar vicinity is higher than the average level in the IGM. These results are evidence that a very hard EUV continuum from this quasar produces a large ionized zone around it. Distinct exceptions are the two brightest He ii quasars at z ≈ 2.8, for which no significant proximity profile is present, probably implying that they are very young.

  8. Proximal Contact Repair of Complex Amalgam Restorations.

    PubMed

    Zguri, M N; Casey, J A; Jessup, J P; Vandewalle, K S

    2017-01-12

    The carving of a complex amalgam restoration may occasionally result in light proximal contact with the adjacent tooth. The purpose of this study was to investigate the strength of complex amalgam restorations repaired with a proximal slot amalgam preparation. Extracted human third molars of similar coronal size were sectioned 1 mm apical to the height of the contour using a saw and were randomly distributed into 9 groups of 10 teeth each. One pin was placed at each line angle of the flattened dentinal tooth surface. A metal matrix band was placed and an admixed alloy was condensed and carved to create a full crown contour but with a flat occlusal surface. A proximal slot was prepared with or without a retention groove and repaired using a single-composition spherical amalgam 15 minutes, 24 hours, one week, or six months after the initial crown condensation. The specimens were stored for 24 hours in 37°C water before fracture at the marginal ridge using a round-ended blade in a universal testing machine. The control group was not repaired. The mean maximum force in newtons and standard deviation were determined per group. Data were analyzed with a 2-way analysis of variance as well as Tukey and Dunnett tests (α=0.05). Significant differences were found between groups based on type of slot preparation (p=0.017) but not on time (p=0.327), with no significant interaction (p=0.152). No significant difference in the strength of the marginal ridge was found between any repair group and the unrepaired control group (p>0.076). The proximal repair strength of a complex amalgam restoration was not significantly different from an unrepaired amalgam crown. Placing a retention groove in the proximal slot preparation resulted in significantly greater fracture strength than a slot with no retention grooves. Time of repair had no significant effect on the strength of the repair.

  9. Bilateral asymmetry of the humerus during growth and development.

    PubMed

    Blackburn, Amanda

    2011-08-01

    The development of handedness throughout growth can be investigated by using bilateral asymmetry of the humerus as a proxy for this trait. A large skeletal sample of nonadults from English archaeological sites was examined using standard metric techniques to assess when right-sided asymmetry first appears in the human skeleton. Results of this work indicate a change in directional asymmetry during growth and development, with infants and young children exhibiting no significant asymmetry and older children and adolescents demonstrating right-sidedness. This trend is consistent with what has been observed in previous studies of upper limb asymmetry in skeletal material and behaviorally in living children, adding further strength to the premise that biomechanical forces strongly influence bilateral asymmetry in the upper limb bones. Variability in the magnitude of asymmetry between different features of the humerus was also noted. This characteristic can be explained by differing degrees of genetic canalization, with length and articular dimensions being more strongly canalized than diaphyseal properties. Copyright © 2011 Wiley-Liss, Inc.

  10. Cortical asymmetries in normal, mild cognitive impairment, and Alzheimer's disease.

    PubMed

    Kim, Jong Hun; Lee, Jong Weon; Kim, Geon Ha; Roh, Jee Hoon; Kim, Min-Jeong; Seo, Sang Won; Kim, Sung Tae; Jeon, Seun; Lee, Jong-Min; Heilman, Kenneth M; Na, Duk L

    2012-09-01

    There are functional and structural neocortical hemispheric asymmetries in people with normal cognition. These asymmetries may be altered in patients with Alzheimer's disease (AD) because there is a loss of neuronal connectivity in the heteromodal cortex. The purpose of this study is to test the hypothesis that individuals with amnestic mild cognitive impairment (aMCI), mild AD, and moderate to severe AD have progressive reductions in thickness asymmetries of the heteromodal neocortex. Right-handed elderly volunteers including normal cognition (NC), aMCI, and AD underwent 3-D volume imaging for cortical thickness. Although the cortical asymmetry pattern observed in normal cognition brains was generally maintained in aMCI and AD, there was a progressive decrease in the degree of asymmetry, especially in the inferior parietal lobule. A reduction of neocortical asymmetries may be a characteristic sign that occurs in patients with AD. Future studies are needed to evaluate whether this loss is specific to AD and if measurements of asymmetry can be used as diagnostic markers and for monitoring disease progression.

  11. Magnetic fields and chiral asymmetry in the early hot universe

    NASA Astrophysics Data System (ADS)

    Sydorenko, Maksym; Tomalak, Oleksandr; Shtanov, Yuri

    2016-10-01

    In this paper, we study analytically the process of external generation and subsequent free evolution of the lepton chiral asymmetry and helical magnetic fields in the early hot universe. This process is known to be affected by the Abelian anomaly of the electroweak gauge interactions. As a consequence, chiral asymmetry in the fermion distribution generates magnetic fields of non-zero helicity, and vice versa. We take into account the presence of thermal bath, which serves as a seed for the development of instability in magnetic field in the presence of externally generated lepton chiral asymmetry. The developed helical magnetic field and lepton chiral asymmetry support each other, considerably prolonging their mutual existence, in the process of `inverse cascade' transferring magnetic-field power from small to large spatial scales. For cosmologically interesting initial conditions, the chiral asymmetry and the energy density of helical magnetic field are shown to evolve by scaling laws, effectively depending on a single combined variable. In this case, the late-time asymptotics of the conformal chiral chemical potential reproduces the universal scaling law previously found in the literature for the system under consideration. This regime is terminated at lower temperatures because of scattering of electrons with chirality change, which exponentially washes out chiral asymmetry. We derive an expression for the termination temperature as a function of the chiral asymmetry and energy density of helical magnetic field.

  12. Analyses of the Variability Asymmetry of Kepler AGNs

    NASA Astrophysics Data System (ADS)

    Chen, Xiao-Yang; Wang, Jun-Xian

    2015-05-01

    The high-quality light curves from the Kepler space telescope make it possible to analyze the optical variability of active galactic nuclei (AGNs) with unprecedented time resolution. Studying the asymmetry in variations could provide independent constraints on physical models for AGN variability. In this paper, we use Kepler observations of 19 sources to perform analyses of the variability asymmetry of AGNs. We apply smoothing correction to light curves to deduct their bias toward high-frequency variability asymmetry caused by long-term variations that have been poorly sampled due to the limited length of light curves. A parameter β based on structure functions is introduced to quantitively describe the asymmetry and its uncertainty is measured using extensive Monte Carlo simulations. Individual sources show no evidence of asymmetry at timescales of 1˜ 20 days and there is no general trend toward positive or negative asymmetry over the whole sample. Stacking the data from all 19 AGNs, we derive an averaged \\bar{β } of 0.00 ± 0.03 and -0.02 ± 0.04 over timescales of 1 ˜ 5 days and 5 ˜ 20 days, respectively, which are statistically consistent with zero. Quasars and Seyfert galaxies show similar asymmetry parameters. Our results indicate that short-term optical variations in AGNs are highly symmetric.

  13. Evaluation of limb load asymmetry using two new mathematical models.

    PubMed

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

    2014-09-25

    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.

  14. Testis asymmetry and sperm length in Rhacophorus omeimontis.

    PubMed

    Mi, Zhi Ping; Liao, Wen Bo; Jin, Long; Lou, Shang Ling; Cheng, Jian; Wu, Hua

    2012-06-01

    Theory predicts that the degree of testes asymmetry should be positively correlated with male body condition in species with directional testis asymmetry. We tested this prediction in Rhacophorus omeimontis, a species in which females mate with more than one male. Our results showed that the treefrogs did not exhibit the absence of directional asymmetry in testis size, but rather the occurrence of fluctuating asymmetry. Moreover, we also tested differences in body size, body mass, testis mass, testis asymmetry, and sperm size among initially paired, jointly paired, and unpaired males. We found that body size and mass, testis mass, testis asymmetry and sperm length did not differ among the three male types. Testis mass showed a positive relationship with soma mass, but the correlations between the extent of fluctuating testis asymmetry and sperm length, and between testis mass and sperm length were not significant. Our data suggest that testes size and sperm length do not play an important role in determining male mating success in the presence of sperm competition.

  15. Hα LINE PROFILE ASYMMETRIES AND THE CHROMOSPHERIC FLARE VELOCITY FIELD

    SciTech Connect

    Kuridze, D.; Mathioudakis, M.; Kennedy, M.; Keenan, F. P.; Simões, P. J. A.; Voort, L. Rouppe van der; Fletcher, L.; Carlsson, M.; Jafarzadeh, S.; Allred, J. C.; Kowalski, A. F.; Graham, D.

    2015-11-10

    The asymmetries observed in the line profiles of solar flares can provide important diagnostics of the properties and dynamics of the flaring atmosphere. In this paper the evolution of the Hα and Ca ii λ8542 lines are studied using high spatial, temporal, and spectral resolution ground-based observations of an M1.1 flare obtained with the Swedish 1 m Solar Telescope. The temporal evolution of the Hα line profiles from the flare kernel shows excess emission in the red wing (red asymmetry) before flare maximum and excess in the blue wing (blue asymmetry) after maximum. However, the Ca ii λ8542 line does not follow the same pattern, showing only a weak red asymmetry during the flare. RADYN simulations are used to synthesize spectral line profiles for the flaring atmosphere, and good agreement is found with the observations. We show that the red asymmetry observed in Hα is not necessarily associated with plasma downflows, and the blue asymmetry may not be related to plasma upflows. Indeed, we conclude that the steep velocity gradients in the flaring chromosphere modify the wavelength of the central reversal in the Hα line profile. The shift in the wavelength of maximum opacity to shorter and longer wavelengths generates the red and blue asymmetries, respectively.

  16. Fluctuating asymmetry, sexual selection and canine teeth in primates.

    PubMed

    Manning, J T; Chamberlain, A T

    1993-02-22

    Fluctuating asymmetry arises as small deviations from symmetry which can be expressed on either side of the body. Increases in fluctuating asymmetry can suggest genomic stress such as results from directional selection. It has been argued that epigamic structures and weapons should show high levels of fluctuating asymmetry because sexual selection is essentially directional in nature. We tested this prediction by examining the expression of fluctuating asymmetry in the upper canines of 21 species of Old World primates. We found, for males but not for females, that asymmetry was correlated with measures of sexual selection including canine dimorphism, canine size, mass dimorphism, and intra-male competition. However, there was no significant correlation with diet type and body mass, which are only weakly associated with sexual selection. Phylogenetic inertia did not account for the association between fluctuating asymmetry and sexual selection. We also found that species with high values of canine dimorphism and intra-male competition tended to have a negative correlation between asymmetry and mean canine height, and this latter effect was present in both males and females. The implications of these findings for sexual selection theory are discussed.

  17. Replenishment success linked to fluctuating asymmetry in larval fish.

    PubMed

    Lemberget, Tove; McCormick, Mark I

    2009-02-01

    Fluctuating asymmetry (FA), defined as random deviations from perfect symmetry, has become a popular tool with which to examine the effects of stress during the development of bilaterally symmetrical organisms. Recent studies have suggested that FA in otoliths may serve as an indicator of stress in fish larvae. We examined the relationship between otolith asymmetry and temporal patterns in the occurrence of late-stage larvae to a tropical reef (i.e. replenishment) for the Caribbean lizardfish, Saurida suspicio (family Synodontidae). Late-stage larvae were collected in light traps over a period of 18 consecutive lunar months in the San Blas Archipelago, Panama. Asymmetry within otolith pairs was calculated from 24 variables: area, perimeter, longest and shortest axis of the otolith and 20 shape descriptors (Fourier harmonics). Otolith asymmetry was correlated strongly with fluctuations in lunar light trap catches. Two measured variables, otolith area and one of the 20 shape descriptors, accounted for 60% of the variability in lunar replenishment of S. suspicio. Individuals from small replenishment pulses exhibited higher levels of asymmetry compared to larvae from large pulses. When dry and wet seasons were analysed separately, otolith asymmetry explained a surprising 70 and 97% of the variation, respectively. Although the generality of these results remain to be tested among other populations and species, otolith asymmetry may be an important indicator, and potentially a predictor, of larval quality and replenishment success.

  18. The heritability of chimpanzee and human brain asymmetry.

    PubMed

    Gómez-Robles, Aida; Hopkins, William D; Schapiro, Steven J; Sherwood, Chet C

    2016-12-28

    Human brains are markedly asymmetric in structure and lateralized in function, which suggests a relationship between these two properties. The brains of other closely related primates, such as chimpanzees, show similar patterns of asymmetry, but to a lesser degree, indicating an increase in anatomical and functional asymmetry during hominin evolution. We analysed the heritability of cerebral asymmetry in chimpanzees and humans using classic morphometrics, geometric morphometrics, and quantitative genetic techniques. In our analyses, we separated directional asymmetry and fluctuating asymmetry (FA), which is indicative of environmental influences during development. We show that directional patterns of asymmetry, those that are consistently present in most individuals in a population, do not have significant heritability when measured through simple linear metrics, but they have marginally significant heritability in humans when assessed through three-dimensional configurations of landmarks that reflect variation in the size, position, and orientation of different cortical regions with respect to each other. Furthermore, genetic correlations between left and right hemispheres are substantially lower in humans than in chimpanzees, which points to a relatively stronger environmental influence on left-right differences in humans. We also show that the level of FA has significant heritability in both species in some regions of the cerebral cortex. This suggests that brain responsiveness to environmental influences, which may reflect neural plasticity, has genetic bases in both species. These results have implications for the evolvability of brain asymmetry and plasticity among humans and our close relatives.

  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.

  20. Fluctuating Asymmetry and Developmental Instability in Sagittal Craniosynostosis

    PubMed Central

    DeLeon, Valerie Burke; Richtsmeier, Joan T.

    2010-01-01

    Objective: To determine whether premature sagittal craniosynostosis is associated with developmental instability in the skull by analyzing fluctuating asymmetry in skull shape. Design: Cranial shape was quantified by collecting coordinate data from landmarks located on three-dimensional reconstructions of preoperative computed tomography (CT) images of 22 children with sagittal craniosynostosis and 22 age-matched controls. A fluctuating asymmetry application of Euclidean distance matrix analysis (EDMA) was used to quantify and compare asymmetry in cranial shape using these landmark data. Results: In contrast to expectations, the sagittal craniosynostosis group did not show a statistically significant increase in the overall level of fluctuating asymmetry relative to the control group. However, we discerned statistically significant localized increases in fluctuating asymmetry in the sagittal craniosynostosis group at pterion and the anterior clinoid processes (α = .05). We also determined a significant correlation of fluctuating asymmetry values between the two groups (r = .71). Conclusions: We conclude that there is no evidence of a role for system-wide developmental instability in the etiology of nonsyndromic sagittal craniosynostosis. However, the localized evidence of asymmetry at the anterior clinoid processes in the sagittal synostosis group suggests an association with the tracts of dura mater that attach there. PMID:19254065

  1. 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

  2. Extent of Structural Asymmetry in Homodimeric Proteins: Prevalence and Relevance

    PubMed Central

    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

  3. Performance and Near-Wake Flow field of A Marine Hydrokinetic Turbine Operating in Free surface Proximity

    NASA Astrophysics Data System (ADS)

    Banerjee, Arindam; Kolekar, Nitin

    2015-11-01

    The current experimental investigation aims at understanding the effect of free surface proximity and associated blockage on near-wake flow-field and performance of a three bladed horizontal axis marine hydrokinetic turbine. Experiments were conducted on a 0.14m radius, three bladed constant chord turbine in a 0.61m ×0.61m test section water channel. The turbine was subjected to various rotational speeds, flow speeds and depths of immersion. Experimental data was acquired through a submerged in-line thrust-torque sensor that was corrected to an unblocked dataset with a blockage correction using measured thrust data. A detailed comparison is presented between blocked and unblocked datasets to identify influence of Reynolds number and free surface proximity on blockage effects. The percent change in Cp was found to be dependent on flow velocity, rotational speed and free surface to blade tip clearance. Further, flow visualization using a stereoscopic particle image velocimetry was carried out in the near-wake region of turbine to understand the mechanism responsible for variation of Cp with rotational speed and free surface proximity. Results revealed presence of slower wake at higher rotational velocities and increased asymmetry in the wake at high free surface proximity.

  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. Using magnetoresistance to probe reversal asymmetry in exchange biased bilayers

    SciTech Connect

    Leighton, C.; Song, M.; Nogues, J.; Cyrille, M. C.; Schuller, Ivan K.

    2000-07-01

    We have measured the anisotropic magnetoresistance of Fe films exchange coupled to antiferromagnetic MnF{sub 2} layers. Exchange bias and coercivity obtained from magnetoresistance are in close agreement with superconducting quantum interference device magnetometry data. In addition the magnetoresistance reveals an asymmetry in the magnetization reversal process, despite the fact that the magnetization hysteresis loops show little shape asymmetry. These results correlate well with an earlier study of magnetization reversal asymmetry by polarized neutron reflectometry. The data imply that the magnetization reverses by coherent rotation on one side of the loop and by nucleation and propagation of domain walls on the other. (c) 2000 American Institute of Physics.

  6. 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.

  7. The asymmetry of radiation: Reinterpreting the Wheeler-Feynman argument

    NASA Astrophysics Data System (ADS)

    Price, Huw

    1991-08-01

    This paper suggests a novel reinterpretation of the mathematical core of Wheeler-Feynman absorber theory, and hence a new route to the conclusion that the temporal asymmetry of classical electromagnetic radiation has the same origin as that of thermodynamics. The argument begins (Sec. 2) with a careful analysis of what the apparent asymmetry of radiation actually involves. Two major flaws in the standard version of the Wheeler-Feynman treatment of radiative asymmetry are then identified (Secs. 4 5), and the proposed reinterpretation is described (Sec. 6). This avoids the two flaws previously mentioned, and also the problematic dependence of radiation on cosmological structure.

  8. Left-right asymmetry in gut development: what happens next?

    PubMed

    Burn, Sally F; Hill, Robert E

    2009-10-01

    The gastrointestinal tract is an asymmetrically patterned organ system. The signals which initiate left-right asymmetry in the developing embryo have been extensively studied, but the downstream steps required to confer asymmetric morphogenesis on the gut organ primordia are less well understood. In this paper we outline key findings on the tissue mechanics underlying gut asymmetry, across a range of species, and use these to synthesise a conserved model for asymmetric gut morphogenesis. We also discuss the importance of correct establishment of left-right asymmetry for gut development and the consequences of perturbations in this process.

  9. 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.

  10. Line Profile Asymmetries in Records from the Multichannel Flare Spectrograph

    NASA Astrophysics Data System (ADS)

    Prosecký, T.

    2007-05-01

    The archive of the Ondřejov Multichannel Flare Spectrograph (MFS) contains video records of several hundreds of flares observed between 1995 and 2004. This contribution shows preliminary results of basic statistical processing on a sample of 50 flares observed in the Hα line between May, 1999 and May, 2001. No significant differences between occurrence of red and blue asymmetries for different flare importance and X-ray classes were found. For the decay phase of a flare no visible asymmetry or faint blue asymmetry seems to be typical.

  11. Asymmetry-driven structure formation in pair plasmas

    SciTech Connect

    Mahajan, S. M.; Shatashvili, N. L.; Berezhiani, V. I.

    2009-12-15

    The nonlinear propagation of electromagnetic waves in pair plasmas, in which the electrostatic potential plays a very important but subdominant role of a 'binding glue' is investigated. Several mechanisms for structure formation are investigated, in particular, the 'asymmetry' in the initial temperatures of the constituent species. It is shown that the temperature asymmetry leads to a (localizing) nonlinearity that is qualitatively different from the ones originating in ambient mass or density difference. The temperature-asymmetry-driven focusing-defocusing nonlinearity supports stable localized wave structures in 1-3 dimensions, which, for certain parameters, may have flat-top shapes.

  12. 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.

  13. Vaccination Rates are Associated With Functional Proximity But Not Base Proximity of Vaccination Clinics.

    PubMed

    Beshears, John; Choi, James J; Laibson, David I; Madrian, Brigitte C; Reynolds, Gwendolyn I

    2016-06-01

    Routine annual influenza vaccinations are recommended for persons 6 months of age and older, but less than half of US adults get vaccinated. Many employers offer employees free influenza vaccinations at workplace clinics, but even then take-up is low. To determine whether employees are significantly more likely to get vaccinated if they have a higher probability of walking by the clinic for reasons other than vaccination. We obtained data from an employer with a free workplace influenza vaccination clinic. Using each employee's building entry/exit swipe card data, we test whether functional proximity-the likelihood that the employee walks by the clinic for reasons other than vaccination-predicts whether the employee gets vaccinated at the clinic. We also test whether base proximity-the inverse of walking distance from the employee's desk to the clinic-predicts vaccination probability. A total of 1801 employees of a health benefits administrator that held a free workplace influenza vaccination clinic. A 2 SD increase in functional proximity is associated with a 6.4 percentage point increase in the probability of vaccination (total vaccination rate at company=40%), even though the average employee's desk is only 166 meters from the clinic. Base proximity does not predict vaccination probability. Minor changes in the environment can have substantial effects on the probability of vaccination. If these results generalize, health systems should emphasize functional proximity over base proximity when locating preventive health services.

  14. Tunable Magnetic Proximity Effects in Graphene Junctions

    NASA Astrophysics Data System (ADS)

    Lazic, Predrag; Belashchenko, Kirill; Zutic, Igor

    2015-03-01

    The characteristic length of the magnetic proximity effects exceed the thickness of a graphene layer leading to an important, but typically overlooked, modifications of equilibrium and transport properties, as well as the implications for graphene spintronics. Using the first-principles studies that integrate a real space density functional theory (GPAW) with the state-of-the art boundary elements electrostatic code based on the Robin Hood method, we explore tunable electronic structure and magnetic proximity effects in the ferromagnet/insulator/graphene junctions. We show that the inclusion of a finite-size gate electrodes and van der Walls interaction lead to nontrivial effects that could also be important in other two-dimensional materials beyond graphene. Work supported by US ONR, NSF-DMR and Nebraska NSF MRSEC.

  15. Clinical Impact of Proximal Autosomal Imbalances

    PubMed Central

    Hamid, AB; Weise, A; Voigt, M; Bucksch, M; Kosyakova, N; Liehr, T; Klein, E

    2012-01-01

    Centromere-near gain of copy number can be induced by intra- or inter-chromosomal rearrangements or by the presence of a small supernumerary marker chromosome (sSMC). Interestingly, partial trisomy to hexasomy of euchromatic material may be present in clinically healthy or affected individuals, depending on origin and size of chromosomal material involved. Here we report the known minimal sizes of all centromere-near, i.e., proximal auto-somal regions in humans, which are tolerated; over 100 Mb of coding DNA are comprised in these regions. Additionally, we have summarized the typical symptoms for nine proximal autosomal regions including genes obviously sensitive to copy numbers. Overall, studying the carriers of specific chromosomal imbalances using genomics-based medicine, combined with single cell analysis can provide the genotype-phenotype correlations and can also give hints where copy-number-sensitive genes are located in the human genome. PMID:24052727

  16. Painful Spastic Hip Dislocation: Proximal Femoral Resection

    PubMed Central

    Albiñana, Javier; Gonzalez-Moran, Gaspar

    2002-01-01

    The dislocated hip in a non-ambulatory child with spastic paresis tends to be a painful interference to sleep, sitting upright, and perineal care. Proximal femoral resection-interposition arthroplasty is one method of treatment for this condition. We reviewed eight hips, two bilateral cases, with a mean follow-up of 30 months. Clinical improvement was observed in all except one case, with respect to pain relief and sitting tolerance. Some proximal migration was observed in three cases, despite routine post-operative skeletal traction in all cases and careful soft tissue interposition. One case showed significant heterotopic ossification which restricted prolonged sitting. This patient needed some occasional medication for pain. PMID:12180614

  17. Goal-proximity decision-making.

    PubMed

    Veksler, Vladislav D; Gray, Wayne D; Schoelles, Michael J

    2013-01-01

    Reinforcement learning (RL) models of decision-making cannot account for human decisions in the absence of prior reward or punishment. We propose a mechanism for choosing among available options based on goal-option association strengths, where association strengths between objects represent previously experienced object proximity. The proposed mechanism, Goal-Proximity Decision-making (GPD), is implemented within the ACT-R cognitive framework. GPD is found to be more efficient than RL in three maze-navigation simulations. GPD advantages over RL seem to grow as task difficulty is increased. An experiment is presented where participants are asked to make choices in the absence of prior reward. GPD captures human performance in this experiment better than RL. Copyright © 2013 Cognitive Science Society, Inc.

  18. Disentangling the Effects of Attentional and Amplitude Asymmetries on Relative Phase Dynamics

    ERIC Educational Resources Information Center

    de Poel, Harjo J.; Peper, C. E.; Beek, Peter J.

    2009-01-01

    Attentional asymmetry in rhythmic interlimb coordination induces an asymmetry in relative phase dynamics, allegedly reflecting an asymmetry in coupling strength. However, relative phase asymmetries may also be engendered by an attention-induced difference between the amplitudes (and hence the preferred frequencies) of the limb movements. The…

  19. Space robotic system for proximity operations

    NASA Technical Reports Server (NTRS)

    Magnani, P. G.; Colomba, M.

    1989-01-01

    Key to an efficient accomplishment of space station servicing operations is the development of a scenario where the presence of man in space is well integrated with the capability of teleoperated and automatic robot system outside the stations. Results focusing on mission requirements, trajectory sequences, propulsion subsystem features, and manipulative kit characteristics relevant to proximity servicing during a Man Tended Free Flyers Robotic Mission (MTFF-RM) are illustrated.

  20. Endoscopic Proximal Hamstring Repair and Ischial Bursectomy

    PubMed Central

    Dierckman, Brian D.; Guanche, Carlos A.

    2012-01-01

    With the significant increase in use of the arthroscope around the hip have come several less invasive techniques to manage pathologies around this joint. This technical note with a video details one such technique that allows for the endoscopic management of proximal hamstring tears and chronic ischial bursitis, which until now have been managed exclusively with much larger open approaches. This procedure allows for complete exposure of the posterior aspect of the hip in a safe, minimally invasive fashion. PMID:23766996

  1. Children's memory and proximity to violence.

    PubMed

    Pynoos, R S; Nader, K

    1989-03-01

    The study examined 133 school-age children's memory of a sniper attack at their elementary school. Researchers analyzed the role that spatial representation, memory markers, inner plans of action, and strategies of recall played in the memory process. In recalling the event, exposed children reduced their degree of life threat, while nonexposed children increased their proximity to the violence. Clinical and forensic implications are discussed.

  2. Capacitive Proximity Sensor Has Longer Range

    NASA Technical Reports Server (NTRS)

    Vranish, John M.

    1992-01-01

    Capacitive proximity sensor on robot arm detects nearby object via capacitive effect of object on frequency of oscillator. Sensing element part of oscillator circuit operating at about 20 kHz. Total capacitance between sensing element and ground constitutes tuning capacitance of oscillator. Sensor circuit includes shield driven by replica of alternating voltage applied to sensing element. Driven shield concentrates sensing electrostatic field in exterior region to enhance sensitivity to object. Sensitivity and dynamic range has corresponding 12-to-1 improvement.

  3. Proximal monomelic amyotrophy of the upper limb.

    PubMed

    Amir, D; Magora, A; Vatine, J J

    1987-07-01

    A 30-year-old patient of Central European origin, suffering from monomelic amyotrophy, is presented. The disease was characterized by proximal weakness of one upper limb, mainly of the shoulder girdle, accompanied by atrophy. The electrodiagnostic examination revealed signs of partial denervation in the presence of normal motor and sensory conduction. The disease, which is probably of the anterior horn cells, had a benign course and good prognosis, as evident from repeated examinations during a follow-up of eight years.

  4. Transverse Stress Fracture of the Proximal Patella

    PubMed Central

    Atsumi, Satoru; Arai, Yuji; Kato, Ko; Nishimura, Akinobu; Nakazora, Shigeto; Nakagawa, Shuji; Ikoma, Kazuya; Fujiwara, Hiroyoshi; Sudo, Akihiro; Kubo, Toshikazu

    2016-01-01

    Abstract Among stress fractures associated with sports activities, patellar stress fracture is rare. Regarding patella stress fractures, so far only distal transverse or lateral longitudinal fractures have been reported, but there are no reports of transverse fractures occurring in the proximal patella. We describe an extremely rare case of transverse stress fracture of proximal patella in a 9-year-old athlete. A 9-year old boy, who participated in sports (sprints and Kendo) presented with left knee pain without any external injury. In plain radiographs, a fracture line was observed in the proximal 1/3 of the left patella, and a patella stress fracture was diagnosed. For treatment, because 7 months of conservative therapy showed no improvement, internal fixation was carried out using Acutrak screws, and bone union was thus achieved. Three months after the operation, he was able to return to his previous level of athletic sports activity. Regarding the mechanism of onset, it is believed that the causes are longitudinal traction force and patellofemoral contact pressure. On the other hand, the contact region of the patella with the femur changes with the flexion angle of the knee. In the current case, the fracture occurred at a site where the patella was in contact with the femur at a flexion angle of >90°, so it is believed that it occurred as a clinical condition from being subjected to repeated longitudinal traction force and patellofemoral contact pressure at a flexion angle of >90°, during the sports activities of sprints and Kendo. The nonunion of the transverse stress fracture of his proximal patella was successfully treated with internal fixation using Acutrak screws. PMID:26871789

  5. Dual-fiber optic microcantilever proximity sensor

    NASA Astrophysics Data System (ADS)

    Goedeke, Shawn; Allison, Stephen W.; Farahi, R. H.; Rajic, Slobodan; Datskos, Panos G.

    2001-12-01

    Microcantilevers are key components of many Micro-Electro- Mechanical Systems (MEMS) and Micro-Optical-Electro- Mechanical Systems (MOEMS) because slight changes to them physically or chemically lead to changes in mechanical characteristics. An inexpensive dual-fiberoptic microcantilever proximity sensor and model to predict its performance are reported here. Motion of a magnetic- material-coated cantilever is the basis of a system under development for measuring magnetic fields. The dual fiber proximity sensor will be used to monitor the motion of the cantilever. The specific goal is to sense induction fields produced by a current carrying conductor. The proximity sensor consists of two fibers side by side with claddings in contact. The fiber core diameter, 50 microns, and cladding thickness, 10 microns, are as small as routinely available commercially with the exception of single mode fiber. Light is launched into one fiber from a light-emitting diode (LED). It emerges from that fiber and reflects from the cantilever into the adjacent receiving fiber connected to a detector. The sensing end is cast molded with a diameter of 3 mm over the last 20 mm, yielding a low profile sensor. This reflective triangulation approach is probably the oldest and simplest fiber proximity sensing approach, yet the novelty here is in demonstrating high sensitivity at low expense from a triangular microstructure with amorphous magnetic coatings of iron, cobalt, permalloy, etc. The signal intensity versus distance curve yields an approximate Gaussian shape. For a typical configuration, the signal grows from 10% to 90% of maximum in traversing from 6 to 50 microns from a coated cantilever. With signal levels exceeding a volt, nanometer resolution should be readily achievable for periodic signals.

  6. Frustration driven stock market dynamics: Leverage effect and asymmetry

    NASA Astrophysics Data System (ADS)

    Ahlgren, Peter Toke Heden; Jensen, Mogens H.; Simonsen, Ingve; Donangelo, Raul; Sneppen, Kim

    2007-09-01

    By applying inverse statistics to financial data it has recently been found from empirical studies that indices exhibit a pronounced gain-loss asymmetry [M.H. Jensen, Phys. Rev. Lett. 83 (1999) 76; I. Simonsen, M.H. Jensen, A. Johansen, Eur. Phys. J. B 27 (2002) 583; M.H. Jensen, A. Johansen, I. Simonsen, Physica A 324 (2003) 338]. This gain-loss asymmetry appears to have some similarities with the stylized fact leverage effect and we investigate if they could be of same origin. For this purpose we introduce the Frustration Governed Market model which includes correlations in time between a model index and its individual stocks. It is shown that the model reproduces very well the empirical findings with respect to gain-loss asymmetry and leverage. In special cases, however, the model may produce leverage without a pronounced gain-loss asymmetry.

  7. Birth order and fluctuating asymmetry: a first look.

    PubMed Central

    Lalumière, M L; Harris, G T; Rice, M E

    1999-01-01

    We investigated the hypothesis that maternal immunoreactivity to male-specific features of the foetus can increase developmental instability. We predicted that the participants' number of older brothers would be positively related to the fluctuating asymmetry of ten bilateral morphological traits. The participants were 40 adult male psychiatric patients and 31 adult male hospital employees. Consistent with the hypothesis, the participants' number of older brothers--but not number of older sisters, younger brothers or younger sisters--was positively associated with fluctuating asymmetry. The patients had significantly larger fluctuating asymmetry scores and tended to have more older brothers than the employees, but the positive relationship between the number of older brothers and fluctuating asymmetry was observed in both groups. PMID:10643079

  8. Impurity poloidal asymmetries and plasma rotation in the PDX Tokamak

    NASA Astrophysics Data System (ADS)

    Brau, K.

    Vertical poloidal asymmetries of carbon and oxygen in the PDX Tokamak were monitored under a variety of discharge conditions in circular plasmas. Near the edge of the plasma and in the region beyond the limiter, the asymmetries appear to be caused by local impurity recycling, variations in the length of the emitting region, and effects due to vertical ion drifts. In the case of C V impurities, the sign and magnitude of the asymmetry is in qualitative agreement with the predictions of a quasi-neoclassical fluid model of impurity transport. A two dimensional computer code is used to simulate different models of poloidal asymmetries, including: (1) poloidally asymmetric source function, (2) charge exchange recombination with neutral hydrogen, (3) poloidally asymmetric electron ensity and temperature profiles, (4) poloidally varying anomalous radial diffusion coefficient, and (5) the quasi-neoclassical fluid model.

  9. 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.

  10. Asymmetry in parkinsonism, spreading pathogens and the nose.

    PubMed

    Hobson, Douglas E

    2012-01-01

    Parkinson's disease, as well as many other parkinsonisms, including most toxic, neurodegenerative and familial types are typically asymmetric. No explanation for this phenomenon exists. A summary of the frequency of asymmetry in a spectrum of parkinsonian disorders is provided. Evidence against asymmetry being the result of normal asymmetries of the substantia nigrais reviewed. Asymmetry either results from a greater susceptibility on one side or a spreading pathology entering or starting on one side of the CNS. With the increasing evidence for spreading pathologies (toxins, viruses, α-synuclein), knowledge of neuroanatomical connections, and literature implicating spreading pathogens from the enteric and olfactory nerves, potential explanations can be theorized and explored, including the possibility of a pathogen preferentially entering or originating in the olfactory bulb on one side, with subsequent involvement of the other side.

  11. Birth order and fluctuating asymmetry: a first look.

    PubMed

    Lalumière, M L; Harris, G T; Rice, M E

    1999-12-07

    We investigated the hypothesis that maternal immunoreactivity to male-specific features of the foetus can increase developmental instability. We predicted that the participants' number of older brothers would be positively related to the fluctuating asymmetry of ten bilateral morphological traits. The participants were 40 adult male psychiatric patients and 31 adult male hospital employees. Consistent with the hypothesis, the participants' number of older brothers--but not number of older sisters, younger brothers or younger sisters--was positively associated with fluctuating asymmetry. The patients had significantly larger fluctuating asymmetry scores and tended to have more older brothers than the employees, but the positive relationship between the number of older brothers and fluctuating asymmetry was observed in both groups.

  12. 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.

  13. Resurrection of large lepton number asymmetries from neutrino flavor oscillations

    NASA Astrophysics Data System (ADS)

    Barenboim, Gabriela; Kinney, William H.; Park, Wan-Il

    2017-02-01

    We numerically solve the evolution equations of neutrino three-flavor density matrices, and show that, even if neutrino oscillations mix neutrino flavors, large lepton number asymmetries are still allowed in certain limits by big bang nucleosynthesis.

  14. Sexually dimorphic brain and behavioral asymmetries in the neonatal rat.

    PubMed Central

    Ross, D A; Glick, S D; Meibach, R C

    1981-01-01

    The 2-deoxy-D-glucose method was used to study asymmetries in cerebral metabolic activity in neonatal rats. Left-right asymmetries in 2-deoxy-D-glucose uptake were observed in hippocampus, diencephalon, cortex, and medulla-pons: 2-deoxy-D-glucose incorporation was greater in right hippocampus, right diencephalon, left cortex, and left medulla-pons. These asymmetries occurred only in females. We also observed neonatal asymmetries in tail position that, in both sexes, were predictive of adult turning preferences; females had right-sided biases in both neonatal and adult characteristics. Collectively these data indicate that cerebral lateralization is sexually dimorphic and is present at birth. Images PMID:6940200

  15. The effect of asymmetry of posture on anticipatory postural adjustments.

    PubMed

    Aruin, Alexander S

    2006-06-19

    The study investigates the effect of body asymmetry on anticipatory postural adjustments (APAs). Subjects performed a task involving a standard load release induced by a shoulder abduction movement while standing symmetrically or in an asymmetrical stance with either their right or left leg in 45 degrees of external rotation. EMG activities of trunk and leg muscles were recorded during the postural perturbation and were quantified within the time intervals typical of APAs. Anticipatory postural adjustments were observed in all experimental conditions. It was found that asymmetrical body positioning was associated with significant asymmetrical patterns of APAs seen in the right and left distal muscles. These APA asymmetries were dependant upon the side in which the body asymmetry was induced: reduced APAs were observed in the leg muscles on the side of leg rotation, while increased APAs were seen in the muscles on the contralateral side. These findings stress the important role that body asymmetries play in the control of upright posture.

  16. Cell polarity determinants establish asymmetry in MEN signaling.

    PubMed

    Monje-Casas, Fernando; Amon, Angelika

    2009-01-01

    Components of the mitotic exit network (MEN), a signaling pathway that triggers exit from mitosis, localize to the spindle pole body (SPB) that migrates into the daughter cell during anaphase but are largely absent from the SPB that remains in the mother cell. Through the analysis of one of the determinants of this asymmetry, Bfa1, we find that the machinery responsible for establishing cell polarity and cytoplasmic microtubules collaborate to establish MEN asymmetry. In cells defective in the Cdc42 signaling pathway or the formin Bni1, Bfa1 localizes to both SPBs. The quantitative analysis of Bfa1 localization further shows that Bfa1 can associate with both SPBs in a transient and highly dynamic fashion, but the protein is stabilized on the SPB that migrates into the daughter cell during anaphase through microtubule-bud cortex interactions. Our results indicate that mother-daughter cell asymmetry determinants establish MEN signaling asymmetry through microtubule-bud cortex interactions.

  17. On the asymmetry of the urban daily air temperature cycle

    NASA Astrophysics Data System (ADS)

    Wang, Kai; Li, Yuguo; Wang, Yi; Yang, Xinyan

    2017-06-01

    The asymmetry phenomenon in daily temperature cycle refers to the smaller and decreasing diurnal temperature range, which resulted from much faster rise of the daily minimum temperature than that of the maximum temperature. The asymmetry is known to have occurred in greater magnitude in cities than rural sites. Spatially, the diurnal temperature range is much smaller in urban areas than in the surrounding rural areas. Temporally, the urban diurnal temperature range decreases much faster than that in the rural areas. Here, we demonstrate a new approach in understanding the spatial and temporal asymmetries in the urban daily air temperature cycle. Both asymmetries can be explained by a simple combination of a reduction in amplitudes with a rise in mean temperature, which are governed by difference factors. Our study provides new insights that increase our understanding of the mechanisms of urban warming.

  18. Asymmetry of normal mandibular condylar shape.

    PubMed

    Ferrario, V F; Sforza, C; Miani, A; Sigurtà, D

    1997-01-01

    Morphological studies of the facial skeleton in human beings are usually made from radiographs (frontal and lateral projections and orthopantomographs). The conventional linear and angular measurements provide quantitative information only about size, and fail to define the shape and form of the skeletal features and their variations. Mathematical methods such as the Fourier series allow a correct quantitative analysis of the shape and its variations. The outlines of the mandibular condyles in the orthopantomographs of 20 men and 20 women (mean age 29 years) were traced and digitized. All subjects had a good dentition, no temporomandibular joint problems, and were referred to a dental surgery for periodontal problems. A Fourier analysis of the outlines was performed. Fourier coefficients and reconstructed outlines were compared to analyze the condylar symmetry of shape on an intra- and intersubject basis. A significant condylar asymmetry for shape as distinct from size was found on an intrasubject basis, i.e. the left and right condyles of a single individual had a different shape with a large interindividual variability. Conversely, the mean condyle shape of the male and female groups was symmetric.

  19. Sibling temperaments, conflict, warmth, and role asymmetry.

    PubMed

    Stoneman, Z; Brody, G H

    1993-12-01

    The association between sibling temperament combinations (activity and adaptability) and qualitative aspects of the sibling relationship were examined, including in-home observations of sibling positivity/warmth, negativity/conflict, social engagement, and role asymmetry and older sibling perceptions of warmth/closeness, conflict, and status/power. The sample consisted of 67 same-gender, school-aged sibling pairs. Highest levels of negativity/conflict occurred when both siblings were high in activity and when the older sibling was rated as more active than the younger. Conflict was lowest when both siblings were low in activity. Warmth/positivity was greatest when both children were similar in activity level. Siblings were more socially engaged when the older sibling was more adaptable than the younger. Perceived status/power was greatest when younger siblings were low in adaptability. When between-temperament-dimension relationships were examined, observed conflict was greatest when older siblings were high in activity and younger siblings were nonadaptable. Gender and age-related findings are also reported. Findings highlight the importance of identifying the complex ways in which varying dimensions of sibling temperaments combine to influence specific aspects of the sibling relationship.

  20. Inter-hemispheric asymmetry of Pedersen conductance

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  1. Hemispheric Asymmetries in Mercury’s Exosphere

    NASA Astrophysics Data System (ADS)

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

    2012-10-01

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

  2. 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.

  3. Persistent asymmetry in the paleomagnetic vector field

    NASA Astrophysics Data System (ADS)

    Love, J. J.

    2001-12-01

    Representing paleomagnetic vectors by a probability density function in a Cartesian three-space of orthogonal, magnetic-field components consisting of a single (unimodal), non-zero mean symmetrical Gaussian function, we can, using a method previously outlined by Love & Constable, estimate the full vectorial mean and variance of the magnetic field at a particular site, and of a particular polarity, even when the data consist of a mixture of directions and intensities. To avoid sampling bias, we restrict our analysis to the 780 kyrs of the Brunhes, and we inspect published data from Hawaii, Mexico, and Réunion, which because of their geographic locations, allow for checks of field symmetry. Comparing our results with published statistical models of the nontransitional mean field and secular variation, we find that the fits are generally inadequate. We conclude that statistically significant mean anomalies, as well as geographic differences in secular variation, require nonzonal terms in a spherical harmonic models of the field. These observations, together with previous work indicating that the mean paleomagnetic field is predominantly a mixture of axial dipolar and quadrupolar ingredients, demonstrate that the mean field and secular variation are asymmetric with respect to the equatorial plane and with respect to longitude. Some of these observations may be due to persistent asymmetry brought about by mixed-parity dynamo states, but they probably also indicate coupling involving lateral heterogeneities at the core-mantle.

  4. Active Region Segmentation Based on Stokes Asymmetries

    NASA Astrophysics Data System (ADS)

    Choi, Jieun; Harker-Lundberg, B.

    2011-01-01

    During the Stokes inversion process, we would ideally use a distinct model for each structure in an active region which addresses the differences in the physical conditions of these regions. While the Milne-Eddington model of the atmosphere---a frequently-used ideal model that assumes all local thermodynamic equilibrium (LTE) conditions are satisfied---is a sufficient approximation for the description of the solar photosphere, we almost always observe deviations from this model. It is thus of interest to devise a method to systematically and accurately identify the active regions based on their spectra, such that we could use a more sophisticated model catered to each structure in an active region during the actual Stokes inversion process. We present a classification scheme for different active region structures using Stokes asymmetries and line core depths as discriminators. The data used for this investigation were obtained from the Synoptic Optical Long-term Investigations of the Sun (SOLIS) facility using the Vector Spectromagnetograph (VSM), observed in a 3 A bandpass around Fe I 6302.5 A, from March 27, 2008 to March 29, 2008. This work is carried out through the National Solar Observatory Research Experiences for Undergraduate (REU) site program, which is co-funded by the Department of Defense in partnership with the National Science Foundation REU Program. The National Solar Observatory is operated by the Association of Universities for Research in Astronomy, Inc. (AURA) under cooperative agreement with the National Science Foundation.

  5. Asymmetry in serial femtosecond crystallography data

    PubMed Central

    Sharma, Amit; Johansson, Linda; Dunevall, Elin; Wahlgren, Weixiao Y.; Neutze, Richard

    2017-01-01

    Serial crystallography is an increasingly important approach to protein crystallography that exploits both X-ray free-electron laser (XFEL) and synchrotron radiation. Serial crystallography recovers complete X-ray diffraction data by processing and merging diffraction images from thousands of randomly oriented non-uniform microcrystals, of which all observations are partial Bragg reflections. Random fluctuations in the XFEL pulse energy spectrum, variations in the size and shape of microcrystals, integrating over millions of weak partial observations and instabilities in the XFEL beam position lead to new types of experimental errors. The quality of Bragg intensity estimates deriving from serial crystallography is therefore contingent upon assumptions made while modeling these data. Here it is observed that serial femtosecond crystallography (SFX) Bragg reflections do not follow a unimodal Gaussian distribution and it is recommended that an idealized assumption of single Gaussian peak profiles be relaxed to incorporate apparent asymmetries when processing SFX data. The phenomenon is illustrated by re-analyzing data collected from microcrystals of the Blastochloris viridis photosynthetic reaction center and comparing these intensity observations with conventional synchrotron data. The results show that skewness in the SFX observations captures the essence of the Wilson plot and an empirical treatment is suggested that can help to separate the diffraction Bragg intensity from the background. PMID:28248658

  6. [Stability of orthodontic treatment of occlusal asymmetry].

    PubMed

    Burstone, C; Filleul, M P; Pigeot, V

    2000-09-01

    A common finding in orthodontic patients is asymmetric occlusion. These asymmetries can be dental, skeletal, or functional in origin. Since many patients have typical posterior overjet the use of Class II-Class III and anterior crisscross elastics are contra-indicated. Even in skeletal discrepancies axial inclination compensation can produce relatively normal overjet in the arch. The best strategy for non-extraction therapy is to move teeth around the arch rather than an en-masse movement of the entire arch. A number of methods for unilateral distalization are discussed. Midline correction requires the determination of facial, apical base, and posterior midpoints. Differential mechanics between patients with apical base discrepancies and no apical base is presented. Although intermaxillary elastics can be indicated the undesirable effects of eruption and frontal occlusal plane tilt should be considered. Advantages in control and ease of occlusal correction rest with intra-arch mechanics. The use of intermaxillary elastics for the correction subdivision cases can lead to instability and or mandibular shifts.

  7. Hemispherical asymmetry in cusp precipitation near solstices

    SciTech Connect

    Newell, P.T.; Meng, C.

    1988-04-01

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

  8. Management of proximal humerus fractures in adults

    PubMed Central

    Vachtsevanos, Leonidas; Hayden, Lydia; Desai, Aravind S; Dramis, Asterios

    2014-01-01

    The majority of proximal humerus fractures are low-energy osteoporotic injuries in the elderly and their incidence is increasing in the light of an ageing population. The diversity of fracture patterns encountered renders objective classification of prognostic value challenging. Non-operative management has been associated with good functional outcomes in stable, minimally displaced and certain types of displaced fractures. Absolute indications for surgery are infrequent and comprise compound, pathological, multi-fragmentary head-splitting fractures and fracture dislocations, as well as those associated with neurovascular injury. A constantly expanding range of reconstructive and replacement options however has been extending the indications for surgical management of complex proximal humerus fractures. As a result, management decisions are becoming increasingly complicated, in an attempt to provide the best possible treatment for each individual patient, that will successfully address their specific fracture configuration, comorbidities and functional expectations. Our aim was to review the management options available for the full range of proximal humerus fractures in adults, along with their specific advantages, disadvantages and outcomes. PMID:25405098

  9. Trajectories in Close Proximity to Asteroids

    NASA Technical Reports Server (NTRS)

    Scheeres, D. J.

    2000-01-01

    Spacecraft motion in close proximity to irregularly shaped, rotating bodies such as asteroids presents a unique dynamical environment as compared to most space missions. There are several fundamental novelties in this environment that spacecraft must deal with. These include the possibility of orbital instabilities that can act over very short time spans (on the order of hours for some systems), possible non-uniform rotation of the central gravity field, divergence of traditional gravity field representations when close to the asteroid surface, dominance of perturbing forces, an extremely large asteroid model parameter space that must be prepared for in the absence of reliable information, and the possibility of employing new and novel trajectory control techniques such as hovering and repeated landings on the asteroid surface. An overview of how these novelties impact the space of feasible close proximity operations and how different asteroid model properties will affect their implementation is given. In so doing, four fundamental types of close proximity operations will be defined. Listed in order of increasing technical difficulty these are: (1) close, stable orbits; (2) low-altitude flyovers; (3) landing trajectories; and (4) hovering trajectories. The feasibility and difficulty of implementing these operations will vary as a function of the asteroid shape, size, density, and rotation properties, and as a function of the spacecraft navigation capability. Additional information is contained in the original extended abstract.

  10. Technical implications in proximal forearm transplantation.

    PubMed

    Haddock, Nicholas T; Chang, Benjamin; Bozentka, David J; Steinberg, David R; Levin, Lawrence Scott

    2013-12-01

    The field of vascularized composite allotransplantation has developed for more than a decade. Investigators are defining patient selection criteria, transplant indications, immunologic regimens, and tolerance. The majority of the current reported hand transplantations have been for treatment of distal forearm or hand amputations. In more proximal amputees, the functional outcome of the transplanted arm has some unique variables that require a different surgical approach. We present a single case of bilateral proximal forearm transplantation in effort to describe the unique technical considerations in this complex procedure. The surgical procedure is described in detail. At 19 months, our patient had 4/5 strength of finger and thumb flexors and protective extensor as well as 4/5 wrist flexors and extensors. Our patient had recovery of sensation. Our patient now lives independently and does her lower extremity prosthesis independently using her hands. These results are expected to continue to improve with more time. In hand transplantation, functional results have been very promising. The described approach of forearm transplantation allows the transfer of the entire functional unit, which should optimize the ultimate outcome for these more proximal injuries.

  11. [Augmentation technique on the proximal humerus].

    PubMed

    Scola, A; Gebhard, F; Röderer, G

    2015-09-01

    The treatment of osteoporotic fractures is still a challenge. The advantages of augmentation with respect to primary in vitro stability and the clinical use for the proximal humerus are presented in this article. In this study six paired human humeri were randomized into an augmented and a non-augmented group. Osteosynthesis was performed with a PHILOS plate (Synthes®). In the augmented group the two screws finding purchase in the weakest cancellous bone were augmented. The specimens were tested in a 3-part fracture model in a varus bending test. The augmented PHILOS plates withstood significantly more load cycles until failure. The correlation to bone mineral density (BMD) showed that augmentation could partially compensate for low BMD. The augmentation of the screws in locked plating in a proximal humerus fracture model is effective in improving the primary stability in a cyclic varus bending test. The targeted augmentation of two particular screws in a region of low bone quality within the humeral head was almost as effective as four screws with twice the amount of bone cement. Screw augmentation combined with a knowledge of the local bone quality could be more effective in enhancing the primary stability of a proximal humerus locking plate because the effect of augmentation can be exploited more effectively limiting it to the degree required. The technique of augmentation is simple and can be applied in open and minimally invasive procedures. When the correct procedure is used, complications (cement leakage into the joint) can be avoided.

  12. Proximity effect correction concerning forward scattering

    NASA Astrophysics Data System (ADS)

    Tsunoda, Dai; Shoji, Masahiro; Tsunoe, Hiroyuki

    2010-09-01

    The Proximity Effect is a critical problem in EB Lithography which is used in Photomask writing. Proximity Effect means that an electron shot by gun scatters by collided with resist molecule or substrate atom causes CD variation depending on pattern density [1]. Scattering by collision with resist molecule is called as "forward scattering", that affects in dozens of nanometer range, and with substrate atom is called as "backward scattering, that affects approximately 10 micrometer in 50keV acceleration voltage respectively. In conventional Proximity Effect Correction (PEC) for mask writing, we don't need to think forward scattering effect. However we should think about forward scattering because of smaller feature size. We have proposed a PEC software product named "PATACON PC-Cluster"[2], which can concern forward scattering and calculate optimum dose modulation. In this communication, we explain the PEC processing throughput when the that takes forward scattering into account. The key technique is to use different processing field size for forward scattering calculation. Additionally, the possibility is shown that effective PEC may be available by connecting forward scattering and backward scattering.

  13. Beam normal spin asymmetry in elastic lepton-nucleon scattering

    SciTech Connect

    M. Gorchtein; P.A.M. Guichon; M. Vanderhaeghen

    2004-04-01

    We discuss the two-photon exchange contribution to observables which involve lepton helicity flip in elastic lepton-nucleon scattering. This contribution is accessed through the spin asymmetry for a lepton beam polarized normal to the scattering plane. We estimate this beam normal spin asymmetry at large momentum transfer using a parton model and we express the corresponding amplitude in terms of generalized parton distributions.

  14. 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.

  15. 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}.

  16. A voxel-based approach to gray matter asymmetries.

    PubMed

    Luders, E; Gaser, C; Jancke, L; Schlaug, G

    2004-06-01

    Voxel-based morphometry (VBM) was used to analyze gray matter (GM) asymmetries in a large sample (n = 60) of male and female professional musicians with and without absolute pitch (AP). We chose to examine these particular groups because previous studies using traditional region-of-interest (ROI) analyses have shown differences in hemispheric asymmetry related to AP and gender. Voxel-based methods may have advantages over traditional ROI-based methods since the analysis can be performed across the whole brain with minimal user bias. After determining that the VBM method was sufficiently sensitive for the detection of differences in GM asymmetries between groups, we found that male AP musicians were more leftward lateralized in the anterior region of the planum temporale (PT) than male non-AP musicians. This confirmed the results of previous studies using ROI-based methods that showed an association between PT asymmetry and the AP phenotype. We further observed that male non-AP musicians revealed an increased leftward GM asymmetry in the postcentral gyrus compared to female non-AP musicians, again corroborating results of a previously published study using ROI-based methods. By analyzing hemispheric GM differences across our entire sample, we were able to partially confirm findings of previous studies using traditional morphometric techniques, as well as more recent, voxel-based analyses. In addition, we found some unusually pronounced GM asymmetries in our musician sample not previously detected in subjects unselected for musical training. Since we were able to validate gender- and AP-related brain asymmetries previously described using traditional ROI-based morphometric techniques, the results of our analyses support the use of VBM for examinations of GM asymmetries.

  17. Age and practice effects on inter-manual performance asymmetry.

    PubMed

    Francis, Karen L; MacRae, Priscilla G; Spirduso, Waneen W; Eakin, Tim

    2014-01-01

    Manual dexterity declines with increasing age, however, the way in which inter-manual asymmetry responds to aging is unclear. Our purpose was to determine the effect of age and practice on inter-manual performance asymmetry in an isometric force pinch line tracing task that varied in difficulty within segments. Thirty right-handed participants, five males and five females in each of three age groups, young (Y20), young-old (O70), and old-old (O80), practiced an isometric force pinch task for 10 trials with each hand on each of five consecutive days. Inter-manual performance asymmetry of the right and left hands was analyzed with a repeated measures analysis of variance (ANOVA) of asymmetry with age groups, practice, task difficulty, and hand as factors. The within-individual magnitude of asymmetry was also analyzed with a repeated measures ANOVA of manual asymmetry calculated as an asymmetry index (AI). Post hoc pair-wise comparisons were performed when significance was found. We observed no inter-manual performance asymmetry on this isometric tracing task among any of the age groups, either in the hand performance differences or in the magnitude of the AI. Age and practice interacted in terms of manual performance: the Y20 and O70 group improved accuracy and task time across the 5 days of practice but the O80 group did not. However, practice did not differentially affect the AI for accuracy or task time for any group. Accuracy of performance of the two hands was differentially affected by practice. All age groups exhibited poorer performance and larger AIs on the most difficult segments of the task (3 and 6) and this did not change with practice.

  18. 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.

  19. 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.

  20. Asymmetries in explosive strength following anterior cruciate ligament reconstruction

    PubMed Central

    Knezevic, Olivera M.; Mirkov, Dragan M.; Kadija, Marko; Nedeljkovic, Aleksandar; Jaric, Slobodan

    2014-01-01

    Background Despite its apparent functional importance, there is a general lack of data regarding the time-related changes in explosive strength and the corresponding side-to-side asymmetries in individuals recovering from an ACL reconstruction (ACLR). The present study was designed to assess changes in the maximum and explosive strength of the quadriceps and hamstrings muscle in athletes recovering from an ACLR. Methods Twenty male athletes with an ACL injury completed a standard isometric testing protocol pre-ACLR, 4 and 6 months post-ACLR. In addition to the maximum strength (Fmax), the explosive strength of quadriceps and hamstrings was assessed through 4 variables derived from the slope of the force-time curves over various time intervals (RFDmax, RFD50, RFD150 and RFD250). Side-to-side asymmetries were calculated relative to post-ACLR measures of the uninvolved leg (“standard” asymmetries), and relative to pre-ACLR value of the uninvolved leg (“real” asymmetries). Results Pre-ACLR asymmetries in quadriceps RFD (average 26%) were already larger than in Fmax (14%) (p < 0.05). Six months post-ACLR real asymmetries in RFD variables (33-39%) were larger than the corresponding standard asymmetries (26-28%; p < 0.01). Average asymmetries in hamstrings RFD and Fmax were 10%, 25% and 15% for pre-ACLR and two post-ACLR sessions, respectively (all p>0.05). Conclusions In addition to the maximum strength, the indices of explosive strength should also be included in monitoring recovery of muscle function following an ACLR. Furthermore, pre-injury/reconstruction values should be used for the post-ACLR side-to-side comparisons, providing a more valid criterion regarding the muscle recovery and readiness for a return to sports. PMID:25112209

  1. Functional asymmetries revealed in visually guided saccades: an FMRI study.

    PubMed

    Petit, Laurent; Zago, Laure; Vigneau, Mathieu; Andersson, Frédéric; Crivello, Fabrice; Mazoyer, Bernard; Mellet, Emmanuel; Tzourio-Mazoyer, Nathalie

    2009-11-01

    Because eye movements are a fundamental tool for spatial exploration, we hypothesized that the neural bases of these movements in humans should be under right cerebral dominance, as already described for spatial attention. We used functional magnetic resonance imaging in 27 right-handed participants who alternated central fixation with either large or small visually guided saccades (VGS), equally performed in both directions. Hemispheric functional asymmetry was analyzed to identify whether brain regions showing VGS activation elicited hemispheric asymmetries. Hemispheric anatomical asymmetry was also estimated to assess its influence on the VGS functional lateralization. Right asymmetrical activations of a saccadic/attentional system were observed in the lateral frontal eye fields (FEF), the anterior part of the intraparietal sulcus (aIPS), the posterior third of the superior temporal sulcus (STS), the occipitotemporal junction (MT/V5 area), the middle occipital gyrus, and medially along the calcarine fissure (V1). The present rightward functional asymmetries were not related to differences in gray matter (GM) density/sulci positions between right and left hemispheres in the precentral, intraparietal, superior temporal, and extrastriate regions. Only V1 asymmetries were explained for almost 20% of the variance by a difference in the position of the right and left calcarine fissures. Left asymmetrical activations of a saccadic motor system were observed in the medial FEF and in the motor strip eye field along the Rolando sulcus. They were not explained by GM asymmetries. We suggest that the leftward saccadic motor asymmetry is part of a general dominance of the left motor cortex in right-handers, which must include an effect of sighting dominance. Our results demonstrate that, although bilateral by nature, the brain network involved in the execution of VGSs, irrespective of their direction, presented specific right and left asymmetries that were not related to

  2. 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.

  3. 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.

  4. The validity of individual frontal alpha asymmetry EEG neurofeedback

    PubMed Central

    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

  5. Mercury exposure may influence fluctuating asymmetry in waterbirds.

    PubMed

    Herring, Garth; Eagles-Smith, Collin A; Ackerman, Joshua T

    2017-06-01

    Variation in avian bilateral symmetry can be an indicator of developmental instability in response to a variety of stressors, including environmental contaminants. The authors used composite measures of fluctuating asymmetry to examine the influence of mercury concentrations in 2 tissues on fluctuating asymmetry within 4 waterbird species. Fluctuating asymmetry increased with mercury concentrations in whole blood and breast feathers of Forster's terns (Sterna forsteri), a species with elevated mercury concentrations. Specifically, fluctuating asymmetry in rectrix feather 1 was the most strongly correlated structural variable of those tested (wing chord, tarsus, primary feather 10, rectrix feather 6) with mercury concentrations in Forster's terns. However, for American avocets (Recurvirostra americana), black-necked stilts (Himantopus mexicanus), and Caspian terns (Hydroprogne caspia), the authors found no relationship between fluctuating asymmetry and either whole-blood or breast feather mercury concentrations, even though these species had moderate to elevated mercury exposure. The results indicate that mercury contamination may act as an environmental stressor during development and feather growth and contribute to fluctuating asymmetry of some species of highly contaminated waterbirds. Environ Toxicol Chem 2017;36:1599-1605. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

  6. Prenatal alcohol exposure alters the patterns of facial asymmetry.

    PubMed

    Klingenberg, C P; Wetherill, L; Rogers, J; Moore, E; Ward, R; Autti-Rämö, I; Fagerlund, A; Jacobson, S W; Robinson, L K; Hoyme, H E; Mattson, S N; Li, T K; Riley, E P; Foroud, T

    2010-01-01

    Directional asymmetry, the systematic differences between the left and right body sides, is widespread in human populations. Changes in directional asymmetry are associated with various disorders that affect craniofacial development. Because facial dysmorphology is a key criterion for diagnosing fetal alcohol syndrome (FAS), the question arises whether in utero alcohol exposure alters directional asymmetry in the face. Data on the relative position of 17 morphologic landmarks were obtained from facial scans of children who were classified as either FAS or control. Shape data obtained from the landmarks were analyzed with the methods of geometric morphometrics. Our analyses showed significant directional asymmetry of facial shape, consisting primarily of a shift of midline landmarks to the right and a displacement of the landmarks around the eyes to the left. The asymmetry of FAS and control groups differed significantly and average directional asymmetry was increased in those individuals exposed to alcohol in utero. These results suggest that the developmental consequences of fetal alcohol exposure affect a wide range of craniofacial features in addition to those generally recognized and used for diagnosis of FAS.

  7. The ecology of asymmetry in stickleback defense structures.

    PubMed

    Reimchen, Thomas E; Bergstrom, Carolyn A

    2009-01-01

    Slight departures from bilateral symmetry are usually associated with reduced fitness. Here we show that an insular freshwater population of Gasterosteus aculeatus exhibits spatial and temporal segregation according to the incidence and direction of asymmetry in the number of bony lateral plates, which are important predator-defense structures. We analyzed 11,263 fish collected from 19 full lake transects over three years, and found that signed asymmetries for plate number were slightly left-side biased. Asymmetries occurred in 55% of the stickleback with more asymmetrics found during cold weather, and more left-biased individuals found during windy conditions, possibly due to environmentally driven activity levels that differ among asymmetric forms. Absolute plate asymmetries were randomly distributed in the lake, but there was a strong shift in signed plate asymmetry from a mean of zero in littoral zones to left-side bias in limnetic zones, probably due to microhabitat choices among asymmetric forms. Video data of avian piscivores on the lake show laterality in prey handling, providing a potential mechanism for asymmetric prey morphology. Our results imply a complex relationship between slight asymmetries and niche space that is relevant to the broader literature on the evolutionary implications of developmental instability and intrapopulation variability.

  8. CMB hemispherical asymmetry from non-linear isocurvature perturbations

    SciTech Connect

    Assadullahi, Hooshyar; Wands, David; Firouzjahi, Hassan; Namjoo, Mohammad Hossein E-mail: firouz@mail.ipm.ir E-mail: david.wands@port.ac.uk

    2015-04-01

    We investigate whether non-adiabatic perturbations from inflation could produce an asymmetric distribution of temperature anisotropies on large angular scales in the cosmic microwave background (CMB). We use a generalised non-linear δ N formalism to calculate the non-Gaussianity of the primordial density and isocurvature perturbations due to the presence of non-adiabatic, but approximately scale-invariant field fluctuations during multi-field inflation. This local-type non-Gaussianity leads to a correlation between very long wavelength inhomogeneities, larger than our observable horizon, and smaller scale fluctuations in the radiation and matter density. Matter isocurvature perturbations contribute primarily to low CMB multipoles and hence can lead to a hemispherical asymmetry on large angular scales, with negligible asymmetry on smaller scales. In curvaton models, where the matter isocurvature perturbation is partly correlated with the primordial density perturbation, we are unable to obtain a significant asymmetry on large angular scales while respecting current observational constraints on the observed quadrupole. However in the axion model, where the matter isocurvature and primordial density perturbations are uncorrelated, we find it may be possible to obtain a significant asymmetry due to isocurvature modes on large angular scales. Such an isocurvature origin for the hemispherical asymmetry would naturally give rise to a distinctive asymmetry in the CMB polarisation on large scales.

  9. 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.

  10. 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.

  11. Running gait impulse asymmetries in below-knee amputees.

    PubMed

    Prince, F; Allard, P; Therrien, R G; McFadyen, B J

    1992-04-01

    In running, large gait asymmetry is expected due to the inability of the foot prosthesis to comply with the kinematic demands and produce a powerful plantarflexion moment. In this work, interlimb asymmetry in below-knee (BK) amputee running gait was assessed for one rigid and three flexible keel prostheses, using vertical and anteroposterior ground reaction forces and respective impulses. Nine BK amputees and 6 controls participated in this study. The running speed was monitored by two light sensitive detectors while the ground reaction forces were measured with a Kistler force plate. Between the prosthetic side and the sound limb the impulse indicator showed greater asymmetry than the force. Interlimb asymmetry was very much present in all types of prosthesis tested but is less pronounced in the flexible keel prostheses. In the latter, the asymmetry may be associated with the force-time history modulation rather than its magnitude alone. Generally, the impulses better describe interlimb asymmetry and the forces allow a greater discrimination between prosthetic foot types.

  12. Mercury exposure may influence fluctuating asymmetry in waterbirds

    USGS Publications Warehouse

    Herring, Garth; Eagles-Smith, Collin A.; Ackerman, Josh

    2017-01-01

    Variation in avian bilateral symmetry can be an indicator of developmental instability in response to a variety of stressors, including environmental contaminants. The authors used composite measures of fluctuating asymmetry to examine the influence of mercury concentrations in 2 tissues on fluctuating asymmetry within 4 waterbird species. Fluctuating asymmetry increased with mercury concentrations in whole blood and breast feathers of Forster's terns (Sterna forsteri), a species with elevated mercury concentrations. Specifically, fluctuating asymmetry in rectrix feather 1 was the most strongly correlated structural variable of those tested (wing chord, tarsus, primary feather 10, rectrix feather 6) with mercury concentrations in Forster's terns. However, for American avocets (Recurvirostra americana), black-necked stilts (Himantopus mexicanus), and Caspian terns (Hydroprogne caspia), the authors found no relationship between fluctuating asymmetry and either whole-blood or breast feather mercury concentrations, even though these species had moderate to elevated mercury exposure. The results indicate that mercury contamination may act as an environmental stressor during development and feather growth and contribute to fluctuating asymmetry of some species of highly contaminated waterbirds.

  13. 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.

  14. The influence of sex chromosome aneuploidy on brain asymmetry.

    PubMed

    Rezaie, Roozbeh; Daly, Eileen M; Cutter, William J; Murphy, Declan G M; Robertson, Dene M W; DeLisi, Lynn E; Mackay, Clare E; Barrick, Thomas R; Crow, Timothy J; Roberts, Neil

    2009-01-05

    The cognitive deficits present in individuals with sex chromosome aneuploidies suggest that hemispheric differentiation of function is determined by an X-Y homologous gene [Crow (1993); Lancet 342:594-598]. In particular, females with Turner's syndrome (TS) who have only one X-chromosome exhibit deficits of spatial ability whereas males with Klinefelter's syndrome (KS) who possess a supernumerary X-chromosome are delayed in acquiring words. Since spatial and verbal abilities are generally associated with right and left hemispheric function, such deficits may relate to anomalies of cerebral asymmetry. We therefore applied a novel image analysis technique to investigate the relationship between sex chromosome dosage and structural brain asymmetry. Specifically, we tested Crow's prediction that the magnitude of the brain torque (i.e., a combination of rightward frontal and leftward occipital asymmetry) would, as a function of sex chromosome dosage, be respectively decreased in TS women and increased in KS men, relative to genotypically normal controls. We found that brain torque was not significantly different in TS women and KS men, in comparison to controls. However, TS women exhibited significantly increased leftward brain asymmetry, restricted to the posterior of the brain and focused on the superior temporal and parietal-occipital association cortex, while KS men showed a trend for decreased brain asymmetry throughout the frontal lobes. The findings suggest that the number of sex chromosomes influences the development of brain asymmetry not simply to modify the torque but in a complex pattern along the antero-posterior axis.

  15. Closing the proximity gap in a metallic Josephson junction between three superconductors

    NASA Astrophysics Data System (ADS)

    Padurariu, C.; Jonckheere, T.; Rech, J.; Mélin, R.; Feinberg, D.; Martin, T.; Nazarov, Yu. V.

    2015-11-01

    We describe the proximity effect in a short disordered metallic junction between three superconducting leads. Andreev bound states in the multiterminal junction may cross the Fermi level. We reveal that for a quasicontinuous metallic density of states, crossings at the Fermi level manifest as a closing of the proximity-induced gap. We calculate the local density of states for a wide range of transport parameters using quantum circuit theory. The gap closes inside an area of the space spanned by the superconducting phase differences. We derive an approximate analytic expression for the boundary of the area and compare it to the full numerical solution. The size of the area increases with the transparency of the junction and is sensitive to asymmetry. The finite density of states at zero energy is unaffected by the electron-hole decoherence present in the junction, although decoherence is important at higher energies. Our predictions can be tested using tunneling transport spectroscopy. To encourage experiments, we calculate the current-voltage characteristic in a typical measurement setup. We show how the structure of the local density of states can be mapped out from the measurement.

  16. Fluid mechanical proximity effects in high-resolution gravure printing for printed electronics

    NASA Astrophysics Data System (ADS)

    Grau, Gerd; Scheideler, William J.; Subramanian, Vivek

    2016-11-01

    Gravure printing is a very promising method for printed electronics because it combines high throughput with high resolution. Recently, printed lines with 2 micrometer resolution have been demonstrated at printing speeds on the order of 1m/s. In order to build realistic circuits, the fluid dynamics of complex pattern formation needs to be studied. Recently, we showed that highly-scaled lines printed in close succession exhibit proximity effects that can either improve or deteriorate print quality depending on a number of parameters. It was found that this effect occurs if cells are connected by a thin fluid film. Here, we present further experimental and modeling results explaining the mechanism by which this thin fluid film affects pattern formation. During the transfer of ink from the roll to the substrate, ink can flow in between connected cells. Asymmetry in the fluid distribution created by the preceding doctor blade wiping process results in net fluid flow from cells that transfer first to cells that transfer subsequently. The proximity of these cells thus affects the final ink distribution on the substrate, which is critically important to understand and design optimally when printing highly-scaled patterns of electronic materials. This work is based upon work supported in part by the National Science Foundation under Cooperative Agreement No. EEC-1160494.

  17. Calibrating animal-borne proximity loggers.

    PubMed

    Rutz, Christian; Morrissey, Michael B; Burns, Zackory T; Burt, John; Otis, Brian; St Clair, James J H; James, Richard

    2015-06-01

    Growing interest in the structure and dynamics of animal social networks has stimulated efforts to develop automated tracking technologies that can reliably record encounters in free-ranging subjects. A particularly promising approach is the use of animal-attached 'proximity loggers', which collect data on the incidence, duration and proximity of spatial associations through inter-logger radio communication. While proximity logging is based on a straightforward physical principle - the attenuation of propagating radio waves with distance - calibrating systems for field deployment is challenging, since most study species roam across complex, heterogeneous environments.In this study, we calibrated a recently developed digital proximity-logging system ('Encounternet') for deployment on a wild population of New Caledonian crows Corvus moneduloides. Our principal objective was to establish a quantitative model that enables robust post hoc estimation of logger-to-logger (and, hence, crow-to-crow) distances from logger-recorded signal-strength values. To achieve an accurate description of the radio communication between crow-borne loggers, we conducted a calibration exercise that combines theoretical analyses, field experiments, statistical modelling, behavioural observations, and computer simulations.We show that, using signal-strength information only, it is possible to assign crow encounters reliably to predefined distance classes, enabling powerful analyses of social dynamics. For example, raw data sets from field-deployed loggers can be filtered at the analysis stage to include predominantly encounters where crows would have come to within a few metres of each other, and could therefore have socially learned new behaviours through direct observation. One of the main challenges for improving data classification further is the fact that crows - like most other study species - associate across a wide variety of habitats and behavioural contexts, with different signal

  18. Effect of surface energy constant and surface asymmetry constant in the charged particle emission cross-section for the reactions $ (78,82,86) Kr +(12) C $ 78 , 82 , 86 K r + 12 C

    NASA Astrophysics Data System (ADS)

    Nazarzadeh, P.; Davoodabadi, S.

    2016-12-01

    The effects of the surface energy constant and the surface asymmetry constant in the charged particle emission cross section, have been examined by using the proximity potentials Prox77, BW91, AW95. The charged particle emission cross-section for the reactions ^{78,82,86} Kr +^{12} C have been calculated. Good consistency between the results of this work and the experimental data have been obtained using appropriate values of these constants.

  19. 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.

  20. European Starlings Are Capable of Discriminating Subtle Size Asymmetries in Paired Stimuli

    PubMed Central

    Swaddle, John P; Johnson, Charles W

    2007-01-01

    Small deviations from bilateral symmetry (fluctuating asymmetries) are cues to fitness differences in some animals. Therefore, researchers have considered whether animals use these small asymmetries as visual cues to determine appropriate behavioral responses (e.g., mate preferences). However, there have been few systematic studies of animals' abilities to visually discriminate such minor asymmetries. If the asymmetries cannot be discriminated, fluctuating asymmetry can not be a visual cue. Here, we report an investigation of European starlings' (Sturnus vulgaris) abilities to discriminate small size asymmetries. We trained starlings, through operant conditioning in a free-flight aviary, to discriminate achromatic, symmetric paired stimuli from size-matched asymmetric stimuli. By starting the learning process with a large asymmetry and progressing through sequential trials of decreasing asymmetry, we elucidated a behavioral limit to asymmetry discrimination. We found that starlings are capable of discriminating a 10% size asymmetry. There was weaker evidence for discrimination of 5% asymmetry but no evidence for signal discrimination at 2.5% size asymmetry. This level of asymmetry discrimination suggests that many size asymmetry cues in nature can be discriminated by birds. At each level of asymmetry discrimination, we also tested whether starlings could generalize their learned symmetry preference to unreinforced novel images. Consistent with previous findings, we found that starlings could generalize their symmetry preferences. PMID:17345950

  1. Proximity and Interactive Learning in University-Firm Relationships

    ERIC Educational Resources Information Center

    Thune, Taran

    2009-01-01

    This paper addresses the question of whether proximity is always necessary for interactive learning, as proposed by recent European innovation theory. Recent research has provided a refined conceptualization of proximity, but there is little empirically-based knowledge about the actual role that proximity plays in relationships intended to foster…

  2. 14 CFR 135.153 - Ground proximity warning system.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Ground proximity warning system. 135.153... Equipment § 135.153 Ground proximity warning system. (a) No person may operate a turbine-powered airplane... equipped with an approved ground proximity warning system. (b) (c) For a system required by this section...

  3. 14 CFR 135.153 - Ground proximity warning system.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Ground proximity warning system. 135.153... Equipment § 135.153 Ground proximity warning system. (a) No person may operate a turbine-powered airplane... equipped with an approved ground proximity warning system. (b) (c) For a system required by this section...

  4. Face-brain asymmetry in autism spectrum disorders.

    PubMed

    Hammond, P; Forster-Gibson, C; Chudley, A E; Allanson, J E; Hutton, T J; Farrell, S A; McKenzie, J; Holden, J J A; Lewis, M E S

    2008-06-01

    The heterogeneity of autism spectrum disorders (ASDs) confounds attempts to identify causes and pathogenesis. Identifiable endophenotypes and reliable biomarkers within ASDs would help to focus molecular research and uncover genetic causes and developmental mechanisms. We used dense surface-modelling techniques to compare the facial morphology of 72 boys with ASD and 128 first-degree relatives to that of 254 unrelated controls. Pattern-matching algorithms were able to discriminate between the faces of ASD boys and those of matched controls (AUC=0.82) and also discriminate between the faces of unaffected mothers of ASD children and matched female controls (AUC=0.76). We detected significant facial asymmetry in boys with ASD (P<0.01), notably depth-wise in the supra- and periorbital regions anterior to the frontal pole of the right hemisphere of the brain. Unaffected mothers of children with ASD display similar significant facial asymmetry, more exaggerated than that in matched controls (P<0.03) and, in particular, show vertical asymmetry of the periorbital region. Unaffected fathers of children with ASD did not show facial asymmetry to a significant degree compared to controls. Two thirds of unaffected male siblings tested were classified unseen as more facially similar to unrelated boys with ASD than to unrelated controls. These unaffected male siblings and two small groups of girls with ASD and female siblings, all show overall directional asymmetry, but without achieving statistical significance in two-tailed t-tests of individual asymmetry of ASD family and matched control groups. We conclude that previously identified right dominant asymmetry of the frontal poles of boys with ASD could explain their facial asymmetry through the direct effect of brain growth. The atypical facial asymmetry of unaffected mothers of children with ASD requires further brain studies before the same explanation can be proposed. An alternative explanation, not mutually exclusive, is a

  5. 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.

  6. Structural hemispheric asymmetries underlie verbal Stroop performance.

    PubMed

    Vallesi, Antonino; Mazzonetto, Ilaria; Ambrosini, Ettore; Babcock, Laura; Capizzi, Mariagrazia; Arbula, Sandra; Tarantino, Vincenza; Semenza, Carlo; Bertoldo, Alessandra

    2017-09-29

    Performance on tasks involving cognitive control such as the Stroop task is often associated with left lateralized brain activations. Based on this neuro-functional evidence, we tested whether leftward structural grey matter asymmetries would also predict inter-individual differences in combatting Stroop interference. To check for the specificity of the results, both a verbal Stroop task and a spatial one were administered to a total of 111 healthy young individuals, for whom T1-weighted magnetic resonance imaging (MRI) images were also acquired. Surface thickness and area estimations were calculated using FreeSurfer. Participants' hemispheres were registered to a symmetric template and Laterality Indices (LI) for the surface thickness and for the area at each vertex in each participant were computed. The correlation of these surface LI measures with the verbal and spatial Stroop effects (incongruent-congruent difference in trial performance) was assessed at each vertex by means of general linear models at the whole-brain level. We found a significant correlation between performance and surface area LI in an inferior posterior temporal cluster (overlapping with the so-called visual word form area, VWFA), with a more left-lateralized area in this region associated with a smaller Stroop effect only in the verbal task. These results point to an involvement of the VWFA for higher-level processes based on word reading, including the suppression of this process when required by the task, and could be interpreted in the context of cross-hemispheric rivalry. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. 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.

  8. Superconductivity in Magnetic and Proximity Effect Systems.

    NASA Astrophysics Data System (ADS)

    Stephan, Walter Hugo

    Some aspects of the theory of superconductors containing paramagnetic impurities in the model of Shiba and Rusinov (SR) are examined. The critical magnetic field deviation function is shown to be very sensitive to the SR scattering parameter varepsilon_0 , with improved agreement with experiment for Zn -Mn as compared to the theory of Abrikosov and Gor'Kov (AG). Optical absorption and thermal conductivity experiments involving a variety of transition metal alloys are reanalyzed including up to three scattering phase shifts, with no significant improvement found over the agreement obtained with only a single phase shift. The electromagnetic coherence length with SR impurities is also considered. Model calculations for superconducting spin-glasses show that systems such as Gd{_ {x}Ce}_{1-{rm x} }{rm Ru_2}, which exhibit significant deviations from the AG prediction for the reduction of the critical temperature with impurity concentration, are also expected to exhibit significant deviations from AG behavior for properties such as the thermodynamic critical field and the electromagnetic penetration depth. The model of Lee for reentrant ferromagnetic superconductors is shown to be only in qualitative agreement with the free energy difference and thermal conductivity determined experimentally for ErRh_{4}B _{4}. A variety of properties of proximity effect junctions are considered within the McMillan model. The temperature dependence of the free energy difference differs significantly from that of a BCS superconductor, with the deviation function becoming much more negative than the BCS prediction. The optical absorption and the low temperature magnetic penetration depth of the normal side of a proximity effect junction with magnetic impurities are also calculated. Finally, the temperature dependence of the zero bias tunneling conductance of a proximity effect induced superconducting spin glass is calculated and found to be in reasonable agreement with experiments

  9. Hand Replantation with Proximal Row Carpectomy

    PubMed Central

    Lee, Young-Keun; Lee, Hang-Ho; Park, Ji-Kang; Kim, Joo-Yong; Dhawan, Vikas

    2008-01-01

    The purpose of this study is to present our operative technique and postoperative results of the hand replantation with proximal row carpectomy in cases of complete amputation at the level of wrist joint. From May 2003 to April 2005, five patients suffered from complete amputation of the hand due to industrial trauma. Amputation level was radiocarpal joint in three cases and midcarpal joint in two cases. Three cases represented guillotine type and two cases with local crush type injuries. All were men and the mean age was 26.6 years. The mean follow-up period was 26.8 months. At the time of replantation, the wrist joint was stabilized with transarticular fixation using three to four Kirschner’s wires after performing proximal row carpectomy. Postoperatively, functional results such as muscle strength, range of motion of the wrist and fingers, and sensory recovery were assessed according to Chen’s criteria. Joint width and arthritic changes of the radio-capitate joint were evaluated with radiologic tools. According to Chen’s criteria, the overall results in five cases were classified as grade II. Intrinsic muscle power of hands was found to be grade 4. The mean grip and pinch powers were 41% and 45%, respectively, compared to contralateral hand. The mean arc of flexion–extension of wrist was 53°. Total mean active motion of fingers was 215 degrees. Static two-point discrimination of fingertip ranged from 8 to 13 mm. On the follow-up, computerized tomography showed well-preserved radio-capitate joint space without any arthritic changes. While performing hand replantation after amputation at the radiocarpal or midcarpal level, proximal row carpectomy is a useful procedure to preserve joint motion of the wrist in selected cases. PMID:18855073

  10. Temporal Proximity Promotes Integration of Overlapping Events.

    PubMed

    Zeithamova, Dagmar; Preston, Alison R

    2017-03-02

    Events with overlapping elements can be encoded as two separate representations or linked into an integrated representation; yet, we know little about the conditions that promote one form of representation over the other. Here, we tested the hypothesis that the proximity of overlapping events would increase the probability of integration. Participants first established memories for house-object and face-object pairs; half of the pairs were learned 24 hr before a fMRI session, and the other half 30 min before the session. During scanning, participants encoded object-object pairs that overlapped with the initial pairs acquired on the same or prior day. Participants were also scanned as they made inference judgments about the relationships among overlapping pairs learned on the same or different day. Participants were more accurate and faster when inferring relationships among memories learned on the same day relative to those acquired across days, suggesting that temporal proximity promotes integration. Evidence for reactivation of existing memories-as measured by a visual content classifier-was equivalent during encoding of overlapping pairs from the two temporal conditions. In contrast, evidence for integration-as measured by a mnemonic strategy classifier from an independent study [Richter, F. R., Chanales, A. J. H., & Kuhl, B. A. Predicting the integration of overlapping memories by decoding mnemonic processing states during learning. Neuroimage, 124, 323-335, 2016]-was greater for same-day overlapping events, paralleling the behavioral results. During inference itself, activation patterns further differentiated when participants were making inferences about events acquired on the same day versus across days. These findings indicate that temporal proximity of events promotes integration and further influences the neural mechanisms engaged during inference.

  11. Asymmetry of Inframammary Folds in Patients Undergoing Augmentation Mammaplasty.

    PubMed

    Yeslev, Max; Braun, Stephane A; Maxwell, G Patrick

    2016-02-01

    Variation in the anatomical position of the inframammary fold (IMF) in women remains poorly studied. The purpose of this study was to evaluate the incidence of asymmetry between IMF locations on the chest wall of women undergoing breast augmentation and to determine breast measurements associated with IMF asymmetry. Three-dimensional imaging analysis of the breasts was performed in 111 women with micromastia, using the Vectra Imaging System(TM). The following measurements were recorded: vertical distance between right and left IMF (inter-fold distance), vertical distance between nipples (inter-nipple distance), and difference between projection of right and left breasts in anterior-posterior direction. Asymmetry between the right and left IMF positions was found in the majority of patients (95.4%), with symmetry only found in 5 patients (4.6%). In the majority of patients (60.3%), the right IMF was located inferior to the left IMF with median inter-fold distance 0.4 cm (range, 0.1, 2.1 cm). In 39 patients (35.1%), the left IMF was located inferior to the right with median inter-fold distance 0.4 cm (range, 0.1, 1.7 cm). There was strong correlation between the degree of asymmetry of IMF and asymmetry of nipple areola complex (NAC) positions (r = 0.687, P < .01). The majority of women with micromastia demonstrate asymmetry of the IMF, which correlates with asymmetry of NAC location. The authors propose a classification system based on most commonly observed IMF locations as types I (right IMF inferior to left), type II (left IMF inferior to right) and type III (both IMF located on the same level). LEVEL OF EVIDENCE 4: Diagnostic. © 2015 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com.

  12. [Diagnosis and therapy of adult patients with facial asymmetry].

    PubMed

    Takano-Yamamoto, Teruko; Kuroda, Shingo

    2009-09-01

    The goal of orthodontic treatment is to improve the patient's life by enhancing dental and jaw functions and dentofacial esthetics [Graber TM, et al., Orthodontics current principles and techniques. 4(e) ed. St Louis: Elsevier, 2005.]. Harmonious occlusion is achieved following improvements of malocclusion via orthodontic treatment [Ehmer U and Broll P, Int J Adult Orthod Orthognath Surg 1992;7:153-159. Throckmorton GS, et al., J Prosthet Dent 1984;51:252-261.]. Perfect facial symmetry is extremely rare, and normal faces have a degree of asymmetry. Patients with dentofacial deformity more frequently have asymmetry of the face and jaws. There was a relationship between the type of malocclusion and the prevalence of asymmetry; 28% of the Class III group, but 40% to 42% of the Class I, Class II and long face groups respectively, were asymmetric [Severt TR and Proffit WR, Int J Adult Orthod Orthogn Surg 1997;12:171-176.]; therefore, facial asymmetry is a common complaint among orthodontic patients. Treatment of severe facial asymmetry in adults consists mainly of surgically repositioning the maxilla or the mandible [Bardinet E, et al., Orthod Fr 2002;73:243-315. Guyuron B, Clin Plast Surg 1989;16:795-801. Proffit WR, et al., Contemporary treatment of dentofacial deformity. 2003. St Louis: Mosby, 2003:574-644.], however, new methods, i.e. orthodontic tooth movement with implant anchorage, have recently been introduced [Costa A, et al., Int J Adult Orthod Orthognath Surg 1998;3:201-209. Creekmore TD and Eklund MK, J Clin Orthod 1983;17:266-269. Miyawaki S,et al., Am J Orthod Dentofacial Orthop 2003;124:373-378. Park HS, et al., J Clin Orthod 2001;35:417-422. Roberts WE, et al., Angle Orthod 1989;59:247-256.], and various treatment options can be chosen in patients with facial asymmetry. In this article, we describe the diagnosis and treatment of adult patients with facial asymmetry.

  13. Quantification of upper limb kinetic asymmetries in front crawl swimming.

    PubMed

    Morouço, Pedro G; Marinho, Daniel A; Fernandes, Ricardo J; Marques, Mário C

    2015-04-01

    This study aimed at quantifying upper limb kinetic asymmetries in maximal front crawl swimming and to examine if these asymmetries would affect the contribution of force exertion to swimming performance. Eighteen high level male swimmers with unilateral breathing patterns and sprint or middle distance specialists, volunteered as participants. A load-cell was used to quantify the forces exerted in water by completing a 30s maximal front crawl tethered swimming test and a maximal 50 m free swimming was considered as a performance criterion. Individual force-time curves were obtained to calculate the mean and maximum forces per cycle, for each upper limb. Following, symmetry index was estimated and breathing laterality identified by questionnaire. Lastly, the pattern of asymmetries along the test was estimated for each upper limb using linear regression of peak forces per cycle. Asymmetrical force exertion was observed in the majority of the swimmers (66.7%), with a total correspondence of breathing laterality opposite to the side of the force asymmetry. Forces exerted by the dominant upper limb presented a higher decrease than from the non-dominant. Very strong associations were found between exerted forces and swimming performance, when controlling the isolated effect of symmetry index. Results point that force asymmetries occur in the majority of the swimmers, and that these asymmetries are most evident in the first cycles of a maximum bout. Symmetry index stood up as an influencing factor on the contribution of tethered forces over swimming performance. Thus, to some extent, a certain degree of asymmetry is not critical for short swimming performance.

  14. Impacted valgus fractures of the proximal humerus.

    PubMed

    Ribeiro, Fabiano Rebouças; Takesian, Fernando Hovaguim; Bezerra, Luiz Eduardo Pimentel; Filho, Rômulo Brasil; Júnior, Antonio Carlos Tenor; da Costa, Miguel Pereira

    2016-01-01

    Impacted valgus fractures of the proximal humerus are considered to be a special type fracture, since impaction of the humeral head on the metaphysis with maintenance of the posteromedial periosteum improves the prognosis regarding occurrences of avascular necrosis. This characteristic can also facilitate the reduction maneuver and increase the consolidation rate of these fractures, even in more complex cases. The studies included were obtained by searching the Bireme, Medline, PubMed, Cochrane Library and Google Scholar databases for those published between 1991 and 2013. The objective of this study was to identify the most common definitions, classifications and treatment methods used for these fractures in the orthopedic medical literature.

  15. Fiber optical ranging sensor for proximity fuse

    NASA Astrophysics Data System (ADS)

    Du, Fang; Chi, Zeying; You, Mingjun; Chen, Wenjian

    1996-09-01

    A fiber optical ranging sensor used in laser proximity fuze is described in this paper. In the fuze, pulse laser diode (LD) is used as light source and trigger signal is generated by comparing the reflected light pulses with the reference pulses by a correlator after they were converted into electric signals by PIN photodiodes. Multi-mode fibers and integrated optical devices are used in the system so that the structure can be more compact. Optical fiber delay line is used to offer precise delay time for reference channel.

  16. Management of posttraumatic proximal interphalangeal joint contracture.

    PubMed

    Houshian, Shirzad; Jing, Shan Shan; Chikkamuniyappa, Chandrasekar; Kazemian, Gholam Hussein; Emami-Moghaddam-Tehrani, Mohammad

    2013-08-01

    Chronic flexion contracture of the proximal interphalangeal (PIP) joint presents a common yet challenging problem to hand surgeons. Over the years, multiple treatment modalities have been described for this problem, producing limited results. Nonoperative treatment using serial casting and splints should be tried before attempting open surgical release, which should be done in selected patients. The use of external fixation for treating PIP contracture has been encouraging and can be a useful alterative. This review provides an update on the current management of PIP joint contractures and presents a flowchart of treatment to aid decision making.

  17. Impacted valgus fractures of the proximal humerus☆

    PubMed Central

    Ribeiro, Fabiano Rebouças; Takesian, Fernando Hovaguim; Bezerra, Luiz Eduardo Pimentel; Filho, Rômulo Brasil; Júnior, Antonio Carlos Tenor; da Costa, Miguel Pereira

    2016-01-01

    Impacted valgus fractures of the proximal humerus are considered to be a special type fracture, since impaction of the humeral head on the metaphysis with maintenance of the posteromedial periosteum improves the prognosis regarding occurrences of avascular necrosis. This characteristic can also facilitate the reduction maneuver and increase the consolidation rate of these fractures, even in more complex cases. The studies included were obtained by searching the Bireme, Medline, PubMed, Cochrane Library and Google Scholar databases for those published between 1991 and 2013. The objective of this study was to identify the most common definitions, classifications and treatment methods used for these fractures in the orthopedic medical literature. PMID:27069878

  18. Periprosthetic proximal femur fractures: current concepts.

    PubMed

    Parvizi, Javad; Vegari, David N

    2011-06-01

    With the increase in demand for total hip and knee arthroplasty, the orthopaedic community has seen a dramatic increase in periprosthetic fractures. Given the high morbidity and mortality associated with these fractures, the orthopaedic surgeon needs to be prepared to deal with this difficult problem. The purpose of this article is to provide the surgeon with an algorithmic approach that allows for easy classification and treatment options for periprosthetic fractures of the proximal femur. Such an approach should prevent the mismanagement of these complications.

  19. Fractures of the proximal humeral epiphysis.

    PubMed

    Burgos-Flores, J; Gonzalez-Herranz, P; Lopez-Mondejar, J A; Ocete-Guzman, J G; Amaya-Alarcón, S

    1993-01-01

    Twenty-two patients with marked displacement of a fracture of the proximal humeral epiphysis have been treated with closed or open reduction and fixation by Kirschner wires. At an average follow-up of 6.8 years there have been good functional results in almost all patients (91.1), with better results in patients under 13 years of age particularly with less residual displacement or angulation. Since there is a greater occurrence of residual deformity and symmetria and limitation of motion in older patients, a more aggressive approach to correct the initial displacement and angulation is warranted in those over the age of 13 years.

  20. Unilateral Isolated Proximal Femoral Focal Deficiency

    PubMed Central

    Doğer, Emek; Köpük, Şule Y.; Çakıroğlu, Yiğit; Çakır, Özgür; Yücesoy, Gülseren

    2013-01-01

    Objective. To discuss a patient with a prenatal diagnosis of unilateral isolated femoral focal deficiency. Case. Antenatal diagnosis of unilateral isolated femoral focal deficiency was made at 20 weeks of gestation. The length of left femur was shorter than the right, and fetal femur length was below the fifth percentile. Proximal femoral focal deficiency was diagnosed. After delivery, the diagnosis was confirmed with skeletal radiographs and magnetic resonance imaging. In prenatal ultrasonographic examination, the early recognition and exclusion of skeletal dysplasias is important; moreover, treatment plans should be initiated, and valuable information should be provided to the family. PMID:23984135

  1. Space station proximity operations and window design

    NASA Technical Reports Server (NTRS)

    Haines, Richard F.

    1988-01-01

    On-orbit proximity operations (PROX-OPS) consist of all extravehicular activity (EVA) within 1 km of the space station. Because of the potentially large variety of PROX-OPS, very careful planning for space station windows is called for and must consider a great many human factors. The following topics are discussed: (1) basic window design philosophy and assumptions; (2) the concept of the local horizontal - local vertical on-orbit; (3) window linear dimensions; (4) selected anthropomorphic considerations; (5) displays and controls relative to windows; and (6) full window assembly replacement.

  2. Open Subpectoral Tenodesis of the Proximal Biceps.

    PubMed

    Voss, Andreas; Cerciello, Simone; Yang, Justin; Beitzel, Knut; Cote, Mark P; Mazzocca, Augustus D

    2016-01-01

    This article summarizes both the various techniques for an open subpectoral biceps tenodesis as well as the biomechanics associated with these procedures. It provides information regarding the indications and contraindications to support the surgeon's decision. Furthermore, a postoperative protocol as well as an outcome overview is presented to address postoperative care. A short summary of the recent literature regarding potential complications is included to provide further insight on this technique. The open subpectoral tenodesis of the long head of the biceps is a safe and reproducible technique with a low complication rate for patients with pathologies of the proximal biceps.

  3. Complications of Proximal Biceps Tenotomy and Tenodesis.

    PubMed

    Virk, Mandeep S; Nicholson, Gregory P

    2016-01-01

    The long head of biceps tendon (LHBT) is a well-recognized cause of anterior shoulder pain. Tenotomy or tenodesis of the LHBT is an effective surgical solution for relieving pain arising from the LHBT. Cosmetic deformity of the arm, cramping or soreness in the biceps muscle, and strength deficits in elbow flexion and supination are the three most common adverse events associated with tenotomy of the LHBT. Complications associated with tenodesis of the LHBT include loss of fixation resulting in cosmetic deformity, residual groove pain, pain or soreness in the biceps muscle, infection, stiffness, hematoma, neurologic injury, vascular injury, proximal humerus fracture, and reflex sympathetic dystrophy.

  4. Supra-threshold Asymmetries in Human Motion Perception

    PubMed Central

    Roditi, Rachel E.; Crane, Benjamin T.

    2012-01-01

    Detection of asymmetries has been a mainstay of using vestibular reflexes to assess semicircular canal function. However, there has been relatively little work on how vestibular stimuli are perceived. Suprathreshold vestibular perception was measured in 13 normal healthy controls by having them compare the relative sizes of two yaw (vertical-axis rotation) or sway (right-left translation) stimuli. Both stimuli were 1.5 s in duration with a staircase used to adjust the relative size of the stimuli to find a pair of stimuli perceived as equal. Motion stimuli were delivered in darkness using a hexapod motion platform, and visual stimuli simulating motion were presented on a screen in the absence of platform motion. Both same direction (SD) and opposite direction (OD) stimuli were delivered in separate runs. After a two-interval stimulus, subjects reported which movement they perceived as larger. Cumulative distribution functions were fit to the responses so that the relative magnitudes of the two stimuli perceived as equal could be determined. For OD trial blocks, a directional asymmetry index (DAI) was calculated to compare the relative size of perceived rightward and leftward motion. For all trial blocks, a temporal asymmetry index (TAI) was used to compare the relative size of the first and second intervals. Motion OD stimuli were perceived as equal in all subjects in yaw and all but one in sway. For visual OD stimuli, two subjects had slightly asymmetric responses for both sway and yaw. The TAI demonstrated asymmetry in 54% in yaw, in which the second interval was perceived to be larger in all but one subject who had an asymmetry. For sway, only two subjects had a significant asymmetry. Visual stimuli produced a similar rate of asymmetry. The direction and magnitude of these asymmetries were not significantly correlated with those seen for motion stimuli. Asymmetries were found in a fraction with the TAI in SD stimuli for motion in yaw (42%) and sway (33%), as

  5. Asymmetry in grasp force matching and sense of effort.

    PubMed

    Adamo, Diane E; Scotland, Samantha; Martin, Bernard J

    2012-03-01

    While asymmetries in upper limb force matching have been observed, the mechanisms underlying asymmetry in the sense of effort have not been conceptualized. The aim of this study was to investigate asymmetries in the perception and reproduction of grasp force. Forty-two young adults, 22 right-handed (RH) and 20 left-handed (LH), were, respectively, divided into three groups according to differences between their right and left-hand strength (left stronger than right, right stronger than left and right & left equivalent). A reference force, representing 20% of the maximal voluntary contraction (MVC) produced by the right or left hand, was matched with same hand (Ipsilateral Remembered--IR) or opposite (Contralateral Remembered--CR) hand. The matching relative error was 92% (for RH) and 46% (for LH) greater in the CR than IR condition. Asymmetries in matching were significant for RH participants only in the CR condition and were dependent on right/left differences in hand strength as shown by the constant error (CE). For this RH population, right-hand overshoot of the left-hand reference and left-hand undershoot of the right-hand reference were significant when the right hand was stronger than the left. Asymmetry remained significant when CE was normalized (%MVC). Asymmetry was reduced when the strength of each hand was equivalent or when the left hand was stronger than the right. These findings suggest that effort perception is asymmetric in RH but not in LH individuals. The hand x strength interaction indicates that asymmetry in force matching is a consequence of both a difference in the respective cortical representations and motor components, which confer a different "gain" (input-output relationship) to each system. The similarity with position sense asymmetry suggests that the gain concept may be generalized to describe some functional/performance differences between the two hand/hemisphere systems. The more symmetrical performance of the LH than RH group

  6. Scattering Effects in Proximity Effect Tunneling Spectroscopy.

    NASA Astrophysics Data System (ADS)

    Gai, Wei

    PETS (Proximity Effect Tunneling Spectroscopy) technique has been applied to Niobium/Yttrium and Niobium/Lutetium bilayers. We have determined electron - phonon interaction parameter lambda_{rm e -ph} is 0.55 for Yttrium and 0.67 for Lutetium. Spin fluctuations parameter lambda_{ rm S} is 0.20 for Yttrium and 0.33 for Lutetium. We found that the large spin fluctuations in Yttrium and Lutetium has responsibility to the absence of superconductivity in them. Our results have given a reasonable explanation of high superconducting transition temperature in them under high pressure. The large reflection coefficient and strong diffuse scattering at Nb/Y and Nb/Lu interface has been discovered and it should have strong influence on the transport properties of metallic superlattices. From the modeling study of elastic scattering in proximity effect tunnel junctions, we have explained why some conventional made high {rm T_{C}} superconducting tunnel junctions give ideal like characteristics in the gap region but variable strength phonon structures in the phonon region.

  7. Carbon nanotube proximity influences rice DNA

    NASA Astrophysics Data System (ADS)

    Katti, Dinesh R.; Sharma, Anurag; Pradhan, Shashindra Man; Katti, Kalpana S.

    2015-07-01

    The uptake of carbon nanotubes (CNT) influences the output of plants, potentially through interactions between the DNA and CNTs. However, little is known about the changes in the plant DNA due to CNT proximity. We report changes in rice plant DNA in the proximity of single walled CNT (SWCNT) using molecular dynamics simulations. The DNA experiences breaking and forming of hydrogen bonds due to unzipping of Watson-Crick (WC) nucleobase pairs and wrapping onto SWCNT. The number of hydrogen bonds between water and DNA nucleobases decreases due to the presence of SWCNT. A higher number of guanine-cytosine (Gua-Cyt) WC hydrogen bonds break as compared to adenine-thymine (Ade-Thy), which suggests that Gua and Cyt bases play a dominant role in DNA-SWCNT interactions. We also find that changes to non-WC nucleobase pairs and van der Waals attractive interactions between WC nucleobase pairs and SWCNT cause significant changes in the conformation of the DNA.

  8. Proximate and polyphenolic characterization of cranberry pomace.

    PubMed

    White, Brittany L; Howard, Luke R; Prior, Ronald L

    2010-04-14

    The proximate composition and identification and quantification of polyphenolic compounds in dried cranberry pomace were determined. Proximate analysis was conducted based on AOAC methods for moisture, protein, fat, dietary fiber, and ash. Other carbohydrates were determined by the difference method. Polyphenolic compounds were identified and quantified by HPLC-ESI-MS. The composition of dried cranberry pomace was 4.5% moisture, 2.2% protein, 12.0% fat, 65.5% insoluble fiber, 5.7% soluble fiber, 8.4% other carbohydrates, 1.1% ash, and 0.6% total polyphenolics. It contained six anthocyanins (111.5 mg/100 g of DW) including derivatives of cyanidin and peonidin. Thirteen flavonols were identified (358.4 mg/100 g of DW), and the aglycones myricetin (55.6 mg/100 g of DW) and quercetin (146.2 mg/100 g of DW) were the most prominent. Procyanidins with degrees of polymerization (DP) of 1-6 were identified (167.3 mg/100 g of DW), the most abundant being an A-type of DP2 (82.6 mg/100 g of DW).

  9. Rheogenic transport in the renal proximal tubule

    PubMed Central

    1983-01-01

    The electrophysiology of the renal Na-K ATPase was studied in isolated perfused amphibian proximal tubules during alterations in bath (serosal) potassium. Intracellular and extracellular ionic activity measurements permitted continuous evaluation of the Nernst potentials for Na+, K+, and Cl- across the basolateral membrane. The cell membrane and transepithelial potential differences and resistances were also determined. Return of K to the basal (serosal) solution after a 20-min incubation in K-free solution hyperpolarized the basolateral membrane to an electrical potential that was more negative than the Nernst potential for either Na, Cl, or K. This constitutes strong evidence that at least under stimulated conditions the Na-K ATPase located at the basolateral membrane of the renal proximal tubule mediates a rheogenic process which directly transfers net charge across the cell membrane. Interpretation of these data in terms of an electrical equivalent circuit permitted calculation of both the rheogenic current and the Na/K coupling ratio of the basolateral pump. During the period between 1 and 3 min after pump reactivation by return of bath K, the basolateral rheogenic current was directly proportional to the intracellular Na activity, and the pump stoichiometry transiently exceeded the coupling ratio of 3Na to 2K reported in other preparations. PMID:6319539

  10. Obesity and Supermarket Access: Proximity or Price?

    PubMed Central

    Aggarwal, Anju; Hurvitz, Philip M.; Monsivais, Pablo; Moudon, Anne V

    2012-01-01

    Objectives. We examined whether physical proximity to supermarkets or supermarket price was more strongly associated with obesity risk. Methods. The Seattle Obesity Study (SOS) collected and geocoded data on home addresses and food shopping destinations for a representative sample of adult residents of King County, Washington. Supermarkets were stratified into 3 price levels based on average cost of the market basket. Sociodemographic and health data were obtained from a telephone survey. Modified Poisson regression was used to test the associations between obesity and supermarket variables. Results. Only 1 in 7 respondents reported shopping at the nearest supermarket. The risk of obesity was not associated with street network distances between home and the nearest supermarket or the supermarket that SOS participants reported as their primary food source. The type of supermarket, by price, was found to be inversely and significantly associated with obesity rates, even after adjusting for individual-level sociodemographic and lifestyle variables, and proximity measures (adjusted relative risk = 0.34; 95% confidence interval = 0.19, 0.63) Conclusions. Improving physical access to supermarkets may be one strategy to deal with the obesity epidemic; improving economic access to healthy foods is another. PMID:22698052

  11. Proteomics of Primary Cilia by Proximity Labeling

    PubMed Central

    Mick, David U.; Rodrigues, Rachel B.; Leib, Ryan D.; Adams, Christopher M.; Chien, Allis S.; Gygi, Steven P.; Nachury, Maxence V.

    2015-01-01

    SUMMARY While cilia are recognized as important signaling organelles, the extent of ciliary functions remains unknown because of difficulties in cataloguing proteins from mammalian primary cilia. We present a method that readily captures rapid snapshots of the ciliary proteome by selectively biotinylating ciliary proteins using a cilia-targeted proximity labeling enzyme (cilia-APEX). Besides identifying known ciliary proteins, cilia-APEX uncovered several ciliary signaling molecules. The kinases PKA, AMPK and LKB1 were validated as bona fide ciliary proteins and PKA was found to regulate Hedgehog signaling in primary cilia. Furthermore, proteomics profiling of Ift27/Bbs19 mutant cilia correctly detected BBSome accumulation inside Ift27−/− cilia and revealed that β-arrestin 2 and the viral receptor CAR are candidate cargoes of the BBSome. This work demonstrates that proximity labeling can be applied to proteomics of non-membrane-enclosed organelles and suggests that proteomics profiling of cilia will enable a rapid and powerful characterization of ciliopathies. PMID:26585297

  12. Synostosis of the Proximal Tibiofibular Joint

    PubMed Central

    Sferopoulos, Nikolaos K.

    2010-01-01

    The incidence of synostosis of the proximal tibiofibular joint (TFJ) was assessed among 1029 patients examined for osteoarthritis of the knee in a 4-year period. Radiographic evidence of a synostosis of the proximal TFJ was demonstrated in 3 knees (3 patients). The synostosis appeared incidental and was not the cause of symptoms in any of them. These patients were further examined with MRI and/or CT scans. In two cases, which were found to be primary (idiopathic), the synostosis was complete and bony. In a third case the lesion was secondary (acquired) to surgical reconstruction for a depressed fracture of the lateral tibial plateau. This iatrogenic complication followed open reduction, internal fixation, and grafting with synthetic bone. The bridging of the joint on the CT views was partial and compatible with ectopic calcification rather than ossification. The patients were treated conservatively and were followed for an average period of 3 years. No evidence that the synostosis accelerated the onset or progression of the degenerative changes to the ipsilateral knee could be verified. PMID:20592991

  13. Phylogenetic proximity revealed by neurodevelopmental event timings.

    PubMed

    Nagarajan, Radhakrishnan; Clancy, Barbara

    2008-01-01

    Statistical properties such as distribution and correlation signatures were investigated using a temporal database of common neurodevelopmental events in the three species most frequently used in experimental studies, rat, mouse, and macaque. There was a fine nexus between phylogenetic proximity and empirically derived dates of the occurrences of 40 common events including the neurogenesis of cortical layers and outgrowth milestones of developing axonal projections. Exponential and power-law approximations to the distribution of the events reveal strikingly similar decay patterns in rats and mice when compared to macaques. Subsequent hierarchical clustering of the common event timings also captures phylogenetic proximity, an association further supported by multivariate linear regression data. These preliminary results suggest that statistical analyses of the timing of developmental milestones may offer a novel measure of phylogenetic classifications. This may have added pragmatic value in the specific support it offers for the reliability of rat/mouse comparative modeling, as well as in the broader implications for the potential of meta-analyses using databases assembled from the extensive empirical literature.

  14. An improved proximity force approximation for electrostatics

    SciTech Connect

    Fosco, Cesar D.; Lombardo, Fernando C.; Mazzitelli, Francisco D.

    2012-08-15

    A quite straightforward approximation for the electrostatic interaction between two perfectly conducting surfaces suggests itself when the distance between them is much smaller than the characteristic lengths associated with their shapes. Indeed, in the so called 'proximity force approximation' the electrostatic force is evaluated by first dividing each surface into a set of small flat patches, and then adding up the forces due two opposite pairs, the contributions of which are approximated as due to pairs of parallel planes. This approximation has been widely and successfully applied in different contexts, ranging from nuclear physics to Casimir effect calculations. We present here an improvement on this approximation, based on a derivative expansion for the electrostatic energy contained between the surfaces. The results obtained could be useful for discussing the geometric dependence of the electrostatic force, and also as a convenient benchmark for numerical analyses of the tip-sample electrostatic interaction in atomic force microscopes. - Highlights: Black-Right-Pointing-Pointer The proximity force approximation (PFA) has been widely used in different areas. Black-Right-Pointing-Pointer The PFA can be improved using a derivative expansion in the shape of the surfaces. Black-Right-Pointing-Pointer We use the improved PFA to compute electrostatic forces between conductors. Black-Right-Pointing-Pointer The results can be used as an analytic benchmark for numerical calculations in AFM. Black-Right-Pointing-Pointer Insight is provided for people who use the PFA to compute nuclear and Casimir forces.

  15. Proximate determinants of fertility in peninsular Malaysia.

    PubMed

    Tey, Nai Peng; Ng, Sor Tho; Yew, Siew Yong

    2012-05-01

    The continuing decline in fertility despite a contraction in contraceptive use in Peninsular Malaysia since the mid-1980s has triggered considerable interest in the reasons behind this phenomenon, such as increase in abortion, sterility, and out-of-wedlock pregnancy. Fertility decline has been attributed to rapid socioeconomic development, which can only influence fertility through the intermediate variables. Application of vital statistics, population census, and survey data of Peninsular Malaysia on Bongaarts's model vindicates that marriage postponement and contraceptive use are the 2 most important proximate determinants of fertility, but the effects are not uniform across the ethnic groups. For instance, the predicted total fertility rate for Chinese and Malays are 2.9 and 1.6, respectively, compared with the observed level of 3.0 and 1.9. Postpartum infecundability and abortion also play a part in explaining ethnic fertility differentials. The fertility inhibiting effects of these proximate determinants have significant implications on reproductive health and future population growth.

  16. Superconducting Proximity Effect in Thin Semiconducting Films

    NASA Astrophysics Data System (ADS)

    Vissers, Michael; Flexner, Soren; Welander, Paul; Inderhees, Kevin; McArdle, Tim; Eckstein, Jim

    2008-03-01

    We report results using a novel 3 terminal device structure that provides two independent resistance measurements that we use to examine the influence of the superconducting proximity effect on both the transport properties of the thin film N layer by quantifying its sheet resistance, Rs, as well as independently measuring the junction conductance across the N-S boundary, Gc. When the N layer is a degenerate semiconductor the changes in these quantities are large. Gc increases much more than the factor of 2 that Andreev Reflection or BTK theory predicts, and both Gc and Rs exhibit reentrance as temperature decreases. We interpret these effects as being due to a transition between a phase fluctuating and phase stiff proximity effect in the N layer. This manifests itself by moving the N-S electrical boundary into the semiconductor, increasing Gc, while simultaneously removing volume available to normal transport forcing the measured Rs to increase. This work was supported by the DOE BES at the F. Seitz Materials Research Laboratory at the University of Illinois, Urbana.

  17. Superconducting Proximity Effect in Thin Semiconducting Films

    NASA Astrophysics Data System (ADS)

    Vissers, Michael; Flexner, Soren; Welander, Paul; Inderhees, Kevin; Eckstein, James

    2007-03-01

    The superconducting proximity effect changes both the transport properties of the N-layer as well as the conductance between the N and S layers. We use a novel 3 terminal device structure to probe this which provides two resistance measurements allowing us to measure both the N-layer sheet resistance, Rs, as well as the junction conductance, Gc. When the N-layer is a degenerate semiconductor, the changes in these quantities are large. Gc increases much more than the factor of 2 that Andreev reflection theory predicts, and both Rs as well as Gc exhibit reentrance as a function of temperature. We interpret these changes as the N-S boundary moving into the semiconductor increasing Gc while simultaneously removing volume in the N-layer that had been used in normal transport. Magnetic fields applied both parallel and perpendicular to the junction cause the maximum conductance to increase while the sheet resistance rises. The magnitude of the necessary field implies a local proximity effect. This work was supported by the DOE BES at the F. Seitz Materials Research Laboratory at the University of Illinois, Urbana.

  18. Empathy: Its ultimate and proximate bases.

    PubMed

    Preston, Stephanie D; de Waal, Frans B M

    2002-02-01

    There is disagreement in the literature about the exact nature of the phenomenon of empathy. There are emotional, cognitive, and conditioning views, applying in varying degrees across species. An adequate description of the ultimate and proximate mechanism can integrate these views. Proximately, the perception of an object's state activates the subject's corresponding representations, which in turn activate somatic and autonomic responses. This mechanism supports basic behaviors (e.g., alarm, social facilitation, vicariousness of emotions, mother-infant responsiveness, and the modeling of competitors and predators) that are crucial for the reproductive success of animals living in groups. The Perception-Action Model (PAM), together with an understanding of how representations change with experience, can explain the major empirical effects in the literature (similarity, familiarity, past experience, explicit teaching, and salience). It can also predict a variety of empathy disorders. The interaction between the PAM and prefrontal functioning can also explain different levels of empathy across species and age groups. This view can advance our evolutionary understanding of empathy beyond inclusive fitness and reciprocal altruism and can explain different levels of empathy across individuals, species, stages of development, and situations.

  19. Frobenius-norm-based measures of quantum coherence and asymmetry

    NASA Astrophysics Data System (ADS)

    Yao, Yao; Dong, G. H.; Xiao, Xing; Sun, C. P.

    2016-08-01

    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.

  20. 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.