From Glass Formation to Icosahedral Ordering by Curving Three-Dimensional Space.

PubMed

Turci, Francesco; Tarjus, Gilles; Royall, C Patrick

2017-05-26

Geometric frustration describes the inability of a local molecular arrangement, such as icosahedra found in metallic glasses and in model atomic glass formers, to tile space. Local icosahedral order, however, is strongly frustrated in Euclidean space, which obscures any causal relationship with the observed dynamical slowdown. Here we relieve frustration in a model glass-forming liquid by curving three-dimensional space onto the surface of a 4-dimensional hypersphere. For sufficient curvature, frustration vanishes and the liquid "freezes" in a fully icosahedral structure via a sharp "transition." Frustration increases upon reducing the curvature, and the transition to the icosahedral state smoothens while glassy dynamics emerge. Decreasing the curvature leads to decoupling between dynamical and structural length scales and the decrease of kinetic fragility. This sheds light on the observed glass-forming behavior in Euclidean space.

The Connection Between Local Icosahedral Order in Metallic Liquids and the Nucleation of Ordered Phases

NASA Technical Reports Server (NTRS)

Curreri, Peter A. (Technical Monitor); Kelton, K. F.; Gangopadhyay, A.; Lee, G. W.; Hyers, R. W.; Rathz, R. J.; Rogers, J.; Schenk, T.; Simonet, V.; Holland-Moritz, D.

2003-01-01

Over fifty years ago, David Turnbull showed that the temperature of many metallic liquids could be decreased far below their equilibrium melting temperature before crystallization occurred. To explain those surprising results, Charles Frank hypothesized that the local structures of undercooled metallic liquids are different from those of crystal phases, containing a significant degree of icosahedral order that is incompatible with extended periodicity. Such structural differences must create a barrier to the formation crystal phases, explaining the observed undercooling behavior. If true, the nucleation from the liquid of phases with extended icosahedral order should be easier. Icosahedral order is often favored in small clusters, as observed recently in liquid-like clusters of pure Pb on the (111) surface of Si, for example. However, it has never been shown that an increasing preference for icosahedral phase formation can be directly linked with the development of icosahedral order in the undercooled liquid. Owing to the combination of very recent advances in levitation techniques and the availability of synchrotron x-ray and high flux neutron facilities, this is shown here.

The Connection Between Local Icosahedral Order in Metallic Liquids and the Nucleation of Ordered Phases

NASA Technical Reports Server (NTRS)

Kelton, K. F.; Gangopadhyay, A. K.; Lee, G. W.; Hyers, R. W.; Rathz, T. J.; Rogers, J. R.; Robinson, M. B.; Schenk, T.; Simonet, V.; Holland-Moritz, D.;

Icosahedral plant viral nanoparticles - bioinspired synthesis of nanomaterials/nanostructures.

PubMed

Narayanan, Kannan Badri; Han, Sung Soo

2017-10-01

Viral nanotechnology utilizes virus nanoparticles (VNPs) and virus-like nanoparticles (VLPs) of plant viruses as highly versatile platforms for materials synthesis and molecular entrapment that can be used in the nanotechnological fields, such as in next-generation nanoelectronics, nanocatalysis, biosensing and optics, and biomedical applications, such as for targeting, therapeutic delivery, and non-invasive in vivo imaging with high specificity and selectivity. In particular, plant virus capsids provide biotemplates for the production of novel nanostructured materials with organic/inorganic moieties incorporated in a very precise and controlled manner. Interestingly, capsid proteins of spherical plant viruses can self-assemble into well-organized icosahedral three-dimensional (3D) nanoscale multivalent architectures with high monodispersity and structural symmetry. Using viral genetic and protein engineering of icosahedral viruses with a variety of sizes, the interior, exterior and the interfaces between coat protein (CP) subunits can be manipulated to fabricate materials with a wide range of desirable properties allowing for biomineralization, encapsulation, infusion, controlled self-assembly, and multivalent ligand display of nanoparticles or molecules for varied applications. In this review, we discuss the various functional nanomaterials/nanostructures developed using the VNPs and VLPs of different icosahedral plant viruses and their nano(bio)technological and nanomedical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

The deviations of the Al6Li3Cu quasicrystal from icosahedral symmetry : a reminiscence of a cubic crystal

NASA Astrophysics Data System (ADS)

Donnadieu, Patricia

1994-05-01

The (Al6Li3Cu) (T2) quasicrystals are known to exhibit large deviations from the icosahedral symmetry. Series of electron diffraction patterns are used to investigate these imperfections in as-cast T, samples. A detailed analysis of the 5-fold and 3-fold symmetry diffraction patterns shows that they are compatible with the m3 point group instead of the m35 icosahedral group. This symmetry reduction is interprétéd as reminiscent of the cubic approximant phase (R-Al5Li3Cu) rather than of higher order approximant phases. This interpretation is supported by previous observations on crystal/quasicrystal phase transformation in the AlLiCu system. Les quasicristaux de phase T2(Al6Li3Cu) montrent d'importantes déviations à la symétrie icosaédrique. Ces imperfections sont mises en évidence par diffraction électronique dans des échantillons de phase T2 brut de coulée. Un examen détaillé des diagrammes de diffraction de symétrie d'ordre 3 et 5 révèle qu'ils sont compatibles avec le groupe ponctuel m3 au lieu du groupe de l'icosaèdre (m35). Cette réduction de symétrie est interprétée comme une réminiscence de la phase cubique approximante (R-Al5Li3Cu) et non l'apparition d'approximant d'ordre plus élevé. Cette interprétation est suggérée par des observations antérieures sur la transformation cristal/quasicristal dans le système AlLiCu.

Speckle in the diffraction patterns of Hendricks-Teller and icosahedral glass models

NASA Technical Reports Server (NTRS)

Garg, Anupam; Levine, Dov

1988-01-01

It is shown that the X-ray diffraction patterns from the Hendricks-Teller model for layered systems and the icosahedral glass models for the icosahedral phases show large fluctuations between nearby scattering wave vectors and from sample to sample, that are quite analogous to laser speckle. The statistics of these fluctuations are studied analytically for the first model and via computer simulations for the second. The observability of these effects is discussed briefly.

The Connection Between Local Icosahedral Order in Metallic Liquids and the Nucleation Behavior of Ordered Phases

NASA Technical Reports Server (NTRS)

Kelton, K. F.; Gangopadhyay, A. K.; Lee, G. W.; Hyers, R. W.; Rathz, T. J.; Rogers, J. R.; Robinson, M. B.; Schenk, T.; Simonet, V.

2003-01-01

Over fifty years ago, David Turnbull showed that the temperature of many metallic liquids could be decreased far below their equilibrium melting temperature before crystallization occurred. To explain those surprising results, Charles Frank hypothesized that the local structures of undercooled metallic liquids are different from those of crystal phases, containing a significant degree of icosahedral order that is incompatible with extended periodicity. Such structural differences must create a barrier to the formation crystal phases, explaining the observed undercooling behavior. If true, the nucleation from the liquid of phases with extended icosahedral order should be easier. Icosahedral order is often favored in small clusters, as observed recently in liquid-like clusters of pure Pb on the (111) surface of Si[3], for example. However, it has never been shown that an increasing preference for icosahedral phase formation can be directly linked with the development of icosahedral order in the undercooled liquid. Owing to the combination of very recent advances in levitation techniques and the availability of synchrotron x-ray and high flux neutron facilities, this is shown here.

Orientation relationship between the T structure and the icosahedral quasicrystal in the Zn-Mg-Al alloy system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakayama, Kei, E-mail: k.n@aoni.waseda.jp; Watanabe, Junya; Koyama, Yasumasa, E-mail: ykoyama@waseda.jp

2016-08-26

To understand the crystallographic relation between the Bergman-type icosahedral quasicrystal and its approximant-T structure, we have investigated the crystallographic features of prepared Zn-Mg-Al alloy samples, mainly by transmission electron microscopy. It was found that there existed three kinds of regions: that is, C14-Laves, approximant-T, and icosahedral-quasicrystal regions, in Zn-Mg-Al alloy samples with the composition of Zn-36at.%Mg-9at.%Al. Among these regions, in particular, we tried to determine an orientation relationship between neighboring icosahedral-quasicrystal and approximant-T regions. Based on the determined relationship, for instance, four threefold rotatory-inversion axes in the T structure were found to be parallel to four of ten threefold rotatory-inversionmore » axes in the icosahedral quasicrystal. It was thus understood that the atomic arrangements of the Bergman-type icosahedral quasicrystal and its approximant-T structure are likely to resemble each other.« less

Mysteries of icosahedral quasicrystals: how are the atoms arranged?

PubMed

Ishimasa, Tsutomu

2016-07-01

Higher-dimensional structure analysis of quasicrystals is now possible. Yamada et al. [IUCrJ (2016), 3, 247-258] have solved the atomic structure of icosahedral ScZn7.33 including the characteristic imperfections.

Method of making an icosahedral boride structure

DOEpatents

Hersee, Stephen D.; Wang, Ronghua; Zubia, David; Aselage, Terrance L.; Emin, David

2005-01-11

A method for fabricating thin films of an icosahedral boride on a silicon carbide (SiC) substrate is provided. Preferably the icosahedral boride layer is comprised of either boron phosphide (B.sub.12 P.sub.2) or boron arsenide (B.sub.12 As.sub.2). The provided method achieves improved film crystallinity and lowered impurity concentrations. In one aspect, an epitaxially grown layer of B.sub.12 P.sub.2 with a base layer or substrate of SiC is provided. In another aspect, an epitaxially grown layer of B.sub.12 As.sub.2 with a base layer or substrate of SiC is provided. In yet another aspect, thin films of B.sub.12 P.sub.2 or B.sub.12 As.sub.2 are formed on SiC using CVD or other vapor deposition means. If CVD techniques are employed, preferably the deposition temperature is above 1050.degree. C., more preferably in the range of 1100.degree. C. to 1400.degree. C., and still more preferably approximately 1150.degree. C.

Breaking Symmetry in Viral Icosahedral Capsids as Seen through the Lenses of X-ray Crystallography and Cryo-Electron Microscopy

PubMed Central

Parent, Kristin N.; Schrad, Jason R.; Cingolani, Gino

2018-01-01

The majority of viruses on Earth form capsids built by multiple copies of one or more types of a coat protein arranged with 532 symmetry, generating an icosahedral shell. This highly repetitive structure is ideal to closely pack identical protein subunits and to enclose the nucleic acid genomes. However, the icosahedral capsid is not merely a passive cage but undergoes dynamic events to promote packaging, maturation and the transfer of the viral genome into the host. These essential processes are often mediated by proteinaceous complexes that interrupt the shell’s icosahedral symmetry, providing a gateway through the capsid. In this review, we take an inventory of molecular structures observed either internally, or at the 5-fold vertices of icosahedral DNA viruses that infect bacteria, archea and eukaryotes. Taking advantage of the recent revolution in cryo-electron microscopy (cryo-EM) and building upon a wealth of crystallographic structures of individual components, we review the design principles of non-icosahedral structural components that interrupt icosahedral symmetry and discuss how these macromolecules play vital roles in genome packaging, ejection and host receptor-binding. PMID:29414851

Metallic-covalent bonding conversion and thermoelectric properties of Al-based icosahedral quasicrystals and approximants.

PubMed

Takagiwa, Yoshiki; Kimura, Kaoru

2014-08-01

In this article, we review the characteristic features of icosahedral cluster solids, metallic-covalent bonding conversion (MCBC), and the thermoelectric properties of Al-based icosahedral quasicrystals and approximants. MCBC is clearly distinguishable from and closely related to the well-known metal-insulator transition. This unique bonding conversion has been experimentally verified in 1/1-AlReSi and 1/0-Al 12 Re approximants by the maximum entropy method and Rietveld refinement for powder x-ray diffraction data, and is caused by a central atom inside the icosahedral clusters. This helps to understand pseudogap formation in the vicinity of the Fermi energy and establish a guiding principle for tuning the thermoelectric properties. From the electron density distribution analysis, rigid heavy clusters weakly bonded with glue atoms are observed in the 1/1-AlReSi approximant crystal, whose physical properties are close to icosahedral Al-Pd-TM (TM: Re, Mn) quasicrystals. They are considered to be an intermediate state among the three typical solids: metals, covalently bonded networks (semiconductor), and molecular solids. Using the above picture and detailed effective mass analysis, we propose a guiding principle of weakly bonded rigid heavy clusters to increase the thermoelectric figure of merit ( ZT ) by optimizing the bond strengths of intra- and inter-icosahedral clusters. Through element substitutions that mainly weaken the inter-cluster bonds, a dramatic increase of ZT from less than 0.01 to 0.26 was achieved. To further increase ZT , materials should form a real gap to obtain a higher Seebeck coefficient.

Metal-organic framework materials based on icosahedral boranes and carboranes

DOEpatents

Mirkin, Chad A.; Hupp, Joseph T.; Farha, Omar K.; Spokoyny, Alexander M.; Mulfort, Karen L.

2010-11-02

Disclosed herein are metal-organic frameworks of metals and boron rich ligands, such as carboranes and icosahedral boranes. Methods of synthesizing and using these materials in gas uptake are disclosed.

Icosahedral quasicrystals as twins of cubic crystals containing large icosahedral clusters of atoms: The 1012-atom primitive cubic structure of Al(6)CuLi(3), the C-phase Al(37)Cu(3)Li(21)Mg(3), and GaMg(2)Zn(3).

PubMed

Pauling, L

1988-06-01

Single-grain precession x-ray diffraction photographs of Al(6)CuLi(3) have been successfully indexed on the basis of icosahedral twinning of cubic crystals with a 1012-atom primitive cubic unit with edge 25.70 A, giving support to the proposal that the so-called icosahedral quasicrystals are twins of crystals containing eight large icosahedral clusters in the beta-W arrangement. In this compound two of the clusters consist of 104 atoms and six consist of 136 atoms, with 24 atoms shared. The same structure is assigned to the C-phase, Al(37)Cu(3)Li(21)Mg(3), and to GaMg(2)Zn(3). A theory of icosahedral quasicrystals and amorphous metals is described.

Sigma-phase packing of icosahedral clusters in 780-atom tetragonal crystals of Cr5Ni3Si2 and V15Ni10Si that by twinning achieve 8-fold rotational point-group symmetry

PubMed Central

Pauling, Linus

1988-01-01

A 780-atom primitive tetragonal unit with edges 27.3, 27.3, and 12.6 Å is assigned to rapidly solidified Cu5Ni3Si2 and V15Ni10Si by analysis of electron diffraction photographs with the assumption that the crystals contain icosahedral clusters. There are thirty 26-atom clusters at the sigma-phase positions. Apparent 8-fold symmetry results from 45° twinning on the basal plane. PMID:16593915

Sigma-phase packing of icosahedral clusters in 780-atom tetragonal crystals of Cr(5)Ni(3)Si(2) and V(15)Ni(10)Si that by twinning achieve 8-fold rotational point-group symmetry.

PubMed

Pauling, L

1988-04-01

A 780-atom primitive tetragonal unit with edges 27.3, 27.3, and 12.6 A is assigned to rapidly solidified Cu(5)Ni(3)Si(2) and V(15)Ni(10)Si by analysis of electron diffraction photographs with the assumption that the crystals contain icosahedral clusters. There are thirty 26-atom clusters at the sigma-phase positions. Apparent 8-fold symmetry results from 45 degrees twinning on the basal plane.

HCIV-1 and Other Tailless Icosahedral Internal Membrane-Containing Viruses of the Family Sphaerolipoviridae.

PubMed

Demina, Tatiana A; Pietilä, Maija K; Svirskaitė, Julija; Ravantti, Janne J; Atanasova, Nina S; Bamford, Dennis H; Oksanen, Hanna M

2017-02-18

Members of the virus family Sphaerolipoviridae include both archaeal viruses and bacteriophages that possess a tailless icosahedral capsid with an internal membrane. The genera Alpha- and Betasphaerolipovirus comprise viruses that infect halophilic euryarchaea, whereas viruses of thermophilic Thermus bacteria belong to the genus Gammasphaerolipovirus . Both sequence-based and structural clustering of the major capsid proteins and ATPases of sphaerolipoviruses yield three distinct clades corresponding to these three genera. Conserved virion architectural principles observed in sphaerolipoviruses suggest that these viruses belong to the PRD1-adenovirus structural lineage. Here we focus on archaeal alphasphaerolipoviruses and their related putative proviruses. The highest sequence similarities among alphasphaerolipoviruses are observed in the core structural elements of their virions: the two major capsid proteins, the major membrane protein, and a putative packaging ATPase. A recently described tailless icosahedral haloarchaeal virus, Haloarcula californiae icosahedral virus 1 (HCIV-1), has a double-stranded DNA genome and an internal membrane lining the capsid. HCIV-1 shares significant similarities with the other tailless icosahedral internal membrane-containing haloarchaeal viruses of the family Sphaerolipoviridae . The proposal to include a new virus species, Haloarcula virus HCIV1 , into the genus Alphasphaerolipovirus was submitted to the International Committee on Taxonomy of Viruses (ICTV) in 2016.

Icosahedral quasicrystals as twins of cubic crystals containing large icosahedral clusters of atoms: The 1012-atom primitive cubic structure of Al6CuLi3, the C-phase Al37Cu3Li21Mg3, and GaMg2Zn3

PubMed Central

Pauling, Linus

1988-01-01

Single-grain precession x-ray diffraction photographs of Al6CuLi3 have been successfully indexed on the basis of icosahedral twinning of cubic crystals with a 1012-atom primitive cubic unit with edge 25.70 Å, giving support to the proposal that the so-called icosahedral quasicrystals are twins of crystals containing eight large icosahedral clusters in the β-W arrangement. In this compound two of the clusters consist of 104 atoms and six consist of 136 atoms, with 24 atoms shared. The same structure is assigned to the C-phase, Al37Cu3Li21Mg3, and to GaMg2Zn3. A theory of icosahedral quasicrystals and amorphous metals is described. PMID:16593929

Pseudo-icosahedral Cr 55 Al 232 - δ as a high-temperature protective material

DOE PAGES

Rosa, R.; Bhattacharya, S.; Pabla, J.; ...

2018-03-19

In this paper, we report here a course of basic research into the potential suitability of a pseudo-icosahedral Cr aluminide as a material for high temperature protective coatings. Cr 55Al 232-δ [δ = 2.70(6)] exhibits high hardness at room temperature as well as low thermal conductivity and excellent oxidation resistance at 973 K, with an oxidation rate comparable to those of softer, denser benchmark materials. Lastly, the origin of these promising properties can be traced to competing long-range and short-range symmetries within the pseudo-icosahedral crystal structure, suggesting new criteria for future materials research.

Pseudo-icosahedral Cr55Al232 -δ as a high-temperature protective material

NASA Astrophysics Data System (ADS)

Rosa, R.; Bhattacharya, S.; Pabla, J.; He, H.; Misuraca, J.; Nakajima, Y.; Bender, A. D.; Antonacci, A. K.; Adrip, W.; McNally, D. E.; Zebro, A.; Kamenov, P.; Geschwind, G.; Ghose, S.; Dooryhee, E.; Ibrahim, A.; Tritt, T. M.; Aronson, M. C.; Simonson, J. W.

2018-03-01

We report here a course of basic research into the potential suitability of a pseudo-icosahedral Cr aluminide as a material for high-temperature protective coatings. Cr55Al232 -δ [ δ =2.70 (6 ) ] exhibits high hardness at room temperature as well as low thermal conductivity and excellent oxidation resistance at 973 K, with an oxidation rate comparable to those of softer, denser benchmark materials. The origin of these promising properties can be traced to competing long-range and short-range symmetries within the pseudo-icosahedral crystal structure, suggesting new criteria for future materials research.

Pseudo-icosahedral Cr 55 Al 232 - δ as a high-temperature protective material

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rosa, R.; Bhattacharya, S.; Pabla, J.

In this paper, we report here a course of basic research into the potential suitability of a pseudo-icosahedral Cr aluminide as a material for high temperature protective coatings. Cr 55Al 232-δ [δ = 2.70(6)] exhibits high hardness at room temperature as well as low thermal conductivity and excellent oxidation resistance at 973 K, with an oxidation rate comparable to those of softer, denser benchmark materials. Lastly, the origin of these promising properties can be traced to competing long-range and short-range symmetries within the pseudo-icosahedral crystal structure, suggesting new criteria for future materials research.

Archaeal Haloarcula californiae Icosahedral Virus 1 Highlights Conserved Elements in Icosahedral Membrane-Containing DNA Viruses from Extreme Environments.

PubMed

Demina, Tatiana A; Pietilä, Maija K; Svirskaitė, Julija; Ravantti, Janne J; Atanasova, Nina S; Bamford, Dennis H; Oksanen, Hanna M

2016-07-19

Despite their high genomic diversity, all known viruses are structurally constrained to a limited number of virion morphotypes. One morphotype of viruses infecting bacteria, archaea, and eukaryotes is the tailless icosahedral morphotype with an internal membrane. Although it is considered an abundant morphotype in extreme environments, only seven such archaeal viruses are known. Here, we introduce Haloarcula californiae icosahedral virus 1 (HCIV-1), a halophilic euryarchaeal virus originating from salt crystals. HCIV-1 also retains its infectivity under low-salinity conditions, showing that it is able to adapt to environmental changes. The release of progeny virions resulting from cell lysis was evidenced by reduced cellular oxygen consumption, leakage of intracellular ATP, and binding of an indicator ion to ruptured cell membranes. The virion contains at least 12 different protein species, lipids selectively acquired from the host cell membrane, and a 31,314-bp-long linear double-stranded DNA (dsDNA). The overall genome organization and sequence show high similarity to the genomes of archaeal viruses in the Sphaerolipoviridae family. Phylogenetic analysis based on the major conserved components needed for virion assembly-the major capsid proteins and the packaging ATPase-placed HCIV-1 along with the alphasphaerolipoviruses in a distinct, well-supported clade. On the basis of its virion morphology and sequence similarities, most notably, those of its core virion components, we propose that HCIV-1 is a member of the PRD1-adenovirus structure-based lineage together with other sphaerolipoviruses. This addition to the lineage reinforces the notion of the ancient evolutionary links observed between the viruses and further highlights the limits of the choices found in nature for formation of a virion. Under conditions of extreme salinity, the majority of the organisms present are archaea, which encounter substantial selective pressure, being constantly attacked by

Crystallography of decahedral and icosahedral particles. II - High symmetry orientations

NASA Technical Reports Server (NTRS)

Yang, C. Y.; Yacaman, M. J.; Heinemann, K.

1979-01-01

Based on the exact crystal structure of decahedral and icosahedral particles, high energy electron diffraction patterns and image profiles have been derived for various high symmetry orientations of the particles with respect to the incident beam. These results form a basis for the identification of small metal particle structures with advanced methods of transmission electron microscopy.

Collisions in outer space produced an icosahedral phase in the Khatyrka meteorite never observed previously in the laboratory.

PubMed

Bindi, Luca; Lin, Chaney; Ma, Chi; Steinhardt, Paul J

2016-12-08

We report the first occurrence of an icosahedral quasicrystal with composition Al 62.0(8) Cu 31.2(8) Fe 6.8(4) , outside the measured equilibrium stability field at standard pressure of the previously reported Al-Cu-Fe quasicrystal (Al x Cu y Fe z , with x between 61 and 64, y between 24 and 26, z between 12 and 13%). The new icosahedral mineral formed naturally and was discovered in the Khatyrka meteorite, a recently described CV3 carbonaceous chondrite that experienced shock metamorphism, local melting (with conditions exceeding 5 GPa and 1,200 °C in some locations), and rapid cooling, all of which likely resulted from impact-induced shock in space. This is the first example of a quasicrystal composition discovered in nature prior to being synthesized in the laboratory. The new composition was found in a grain that has a separate metal assemblage containing icosahedrite (Al 63 Cu 24 Fe 13 ), currently the only other known naturally occurring mineral with icosahedral symmetry (though the latter composition had already been observed in the laboratory prior to its discovery in nature). The chemistry of both the icosahedral phases was characterized by electron microprobe, and the rotational symmetry was confirmed by means of electron backscatter diffraction.

Collisions in outer space produced an icosahedral phase in the Khatyrka meteorite never observed previously in the laboratory

PubMed Central

Bindi, Luca; Lin, Chaney; Ma, Chi; Steinhardt, Paul J.

2016-01-01

We report the first occurrence of an icosahedral quasicrystal with composition Al62.0(8)Cu31.2(8)Fe6.8(4), outside the measured equilibrium stability field at standard pressure of the previously reported Al-Cu-Fe quasicrystal (AlxCuyFez, with x between 61 and 64, y between 24 and 26, z between 12 and 13%). The new icosahedral mineral formed naturally and was discovered in the Khatyrka meteorite, a recently described CV3 carbonaceous chondrite that experienced shock metamorphism, local melting (with conditions exceeding 5 GPa and 1,200 °C in some locations), and rapid cooling, all of which likely resulted from impact-induced shock in space. This is the first example of a quasicrystal composition discovered in nature prior to being synthesized in the laboratory. The new composition was found in a grain that has a separate metal assemblage containing icosahedrite (Al63Cu24Fe13), currently the only other known naturally occurring mineral with icosahedral symmetry (though the latter composition had already been observed in the laboratory prior to its discovery in nature). The chemistry of both the icosahedral phases was characterized by electron microprobe, and the rotational symmetry was confirmed by means of electron backscatter diffraction. PMID:27929519

Controlling the Growth of Au on Icosahedral Seeds of Pd by Manipulating the Reduction Kinetics

DOE PAGES

Lv, Tian; Yang, Xuan; Zheng, Yiqun; ...

2016-03-29

This article reports a systematic study of how Au atoms nucleate and grow on Pd icosahedral seeds with a multiply twinned structure. By manipulating the reduction kinetics, we obtained Pd–Au bimetallic nanocrystals with two distinct shapes and structures. Specifically, Pd@Au core–shell icosahedra were formed when a relatively fast reduction rate was used for the HAuCl 4 precursor. At a slow reduction rate, in contrast, the nucleation and growth of Au atoms were mainly confined to one of the vertices of a Pd icosahedral seed, resulting in the formation of a Au icosahedron by sharing five adjacent faces with the Pdmore » seed. The same growth pattern was observed for Pd icosahedral seeds with both sizes of 32 and 20 nm. Also, we have also investigated the effects of other kinetic parameters, including the concentration of reducing agent and reaction temperature, on the growth pathway undertaken by the Au atoms. In conclusion, we believe that the mechanistic insights obtained from this study can be extended to other systems, including the involvement of different metals and/or seeds with different morphologies.« less

Additional evidence from x-ray powder diffraction patterns that icosahedral quasi-crystals of intermetallic compounds are twinned cubic crystals

PubMed Central

Pauling, Linus

1988-01-01

Analysis of the measured values of Q for the weak peaks (small maxima, usually considered to be background fluctuations, “noise”) on the x-ray powder diffraction curves for 17 rapidly quenched alloys leads directly to the conclusion that they are formed by an 820-atom or 1012-atom primitive cubic structure that by icosahedral twinning produces the so-called icosahedral quasi-crystals. PMID:16593948

Cooperative Formation of Icosahedral Proline Clusters from Dimers

NASA Astrophysics Data System (ADS)

Jacobs, Alexander D.; Jovan Jose, K. V.; Horness, Rachel; Raghavachari, Krishnan; Thielges, Megan C.; Clemmer, David E.

2018-01-01

Ion mobility spectrometry-mass spectrometry and Fourier transform infrared spectroscopy (FTIR) techniques were combined with quantum chemical calculations to examine the origin of icosahedral clusters of the amino acid proline. When enantiopure proline solutions are electrosprayed (using nanospray) from 100 mM ammonium acetate, only three peaks are observed in the mass spectrum across a concentration range of five orders of magnitude: a monomer [Pro+H]+ species, favored from 0.001 to 0.01 mM proline concentrations; a dimer [2Pro+H]+ species, the most abundant species for proline concentrations above 0.01 mM; and, the dimer and dodecamer [12Pro+2H]2+ for 1.0 mM and more concentrated proline solutions. Electrospraying racemic D/ L-proline solutions from 100 mM ammonium acetate leads to a monomer at low proline concentrations (0.001 to 0.1 mM), and a dimer at higher concentrations (>0.09 mM), as well as a very small population of 8 to 15 Pro clusters that comprise <0.1% of the total ion signals even at the highest proline concentration. Solution FTIR studies show unique features that increase in intensity in the enantiopure proline solutions, consistent with clustering, presumably from the icosahedral geometry in bulk solution. When normalized for the total proline, these results are indicative of a cooperative formation of the enantiopure 12Pro species from 2Pro. [Figure not available: see fulltext.

Nonhydrostatic icosahedral atmospheric model (NICAM) for global cloud resolving simulations

NASA Astrophysics Data System (ADS)

Satoh, M.; Matsuno, T.; Tomita, H.; Miura, H.; Nasuno, T.; Iga, S.

2008-03-01

A new type of ultra-high resolution atmospheric global circulation model is developed. The new model is designed to perform "cloud resolving simulations" by directly calculating deep convection and meso-scale circulations, which play key roles not only in the tropical circulations but in the global circulations of the atmosphere. Since cores of deep convection have a few km in horizontal size, they have not directly been resolved by existing atmospheric general circulation models (AGCMs). In order to drastically enhance horizontal resolution, a new framework of a global atmospheric model is required; we adopted nonhydrostatic governing equations and icosahedral grids to the new model, and call it Nonhydrostatic ICosahedral Atmospheric Model (NICAM). In this article, we review governing equations and numerical techniques employed, and present the results from the unique 3.5-km mesh global experiments—with O(10 9) computational nodes—using realistic topography and land/ocean surface thermal forcing. The results show realistic behaviors of multi-scale convective systems in the tropics, which have not been captured by AGCMs. We also argue future perspective of the roles of the new model in the next generation atmospheric sciences.

Simulations of polymorphic icosahedral shells assembling around many cargo molecules

NASA Astrophysics Data System (ADS)

Mohajerani, Farzaneh; Perlmutter, Jason; Hagan, Michael

Bacterial microcompartments (BMCs) are large icosahedral shells that sequester the enzymes and reactants responsible for particular metabolic pathways in bacteria. Although different BMCs vary in size and encapsulate different cargoes, they are constructed from similar pentameric and hexameric shell proteins. Despite recent groundbreaking experiments which visualized the formation of individual BMCs, the detailed assembly pathways and the factors which control shell size remain unclear. In this talk, we describe theoretical and computational models that describe the dynamical encapsulation of hundreds of cargo molecules by self-assembling icosahedral shells. We present phase diagrams and analysis of dynamical simulation trajectories showing how the thermodynamics, assembly pathways, and emergent structures depend on the interactions among shell proteins and cargo molecules. Our model suggests a mechanism for controlling insertion of the 12 pentamers required for a closed shell topology, and the relationship between assembly pathway and BMC size polydispersity. In addition to elucidating how native BMCs assemble,our results establish principles for reengineering BMCs or viral capsids as customizable nanoreactors that can assemble around a programmable set of enzymes and reactants. Supported by NIH R01GM108021 and Brandeis MRSEC DMR-1420382.

Analysis of phases in the structure determination of an icosahedral virus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plevka, Pavel; Kaufmann, Bärbel; Rossmann, Michael G.

2012-03-15

The constraints imposed on structure-factor phases by noncrystallographic symmetry (NCS) allow phase improvement, phase extension to higher resolution and hence ab initio phase determination. The more numerous the NCS redundancy and the greater the volume used for solvent flattening, the greater the power for phase determination. In a case analyzed here the icosahedral NCS phasing appeared to have broken down, although later successful phase extension was possible when the envelope around the NCS region was tightened. The phases from the failed phase-determination attempt fell into four classes, all of which satisfied the NCS constraints. These four classes corresponded to themore » correct solution, opposite enantiomorph, Babinet inversion and opposite enantiomorph with Babinet inversion. These incorrect solutions can be seeded from structure factors belonging to reciprocal-space volumes that lie close to icosahedral NCS axes where the structure amplitudes tend to be large and the phases tend to be 0 or {pi}. Furthermore, the false solutions can spread more easily if there are large errors in defining the envelope designating the region in which NCS averaging is performed.« less

Analysis of phases in the structure determination of an icosahedral virus

PubMed Central

Plevka, Pavel; Kaufmann, Bärbel; Rossmann, Michael G.

2011-01-01

The constraints imposed on structure-factor phases by non­crystallographic symmetry (NCS) allow phase improvement, phase extension to higher resolution and hence ab initio phase determination. The more numerous the NCS redundancy and the greater the volume used for solvent flattening, the greater the power for phase determination. In a case analyzed here the icosahedral NCS phasing appeared to have broken down, although later successful phase extension was possible when the envelope around the NCS region was tightened. The phases from the failed phase-determination attempt fell into four classes, all of which satisfied the NCS constraints. These four classes corresponded to the correct solution, opposite enantiomorph, Babinet inversion and opposite enantiomorph with Babinet inversion. These incorrect solutions can be seeded from structure factors belonging to reciprocal-space volumes that lie close to icosahedral NCS axes where the structure amplitudes tend to be large and the phases tend to be 0 or π. Furthermore, the false solutions can spread more easily if there are large errors in defining the envelope designating the region in which NCS averaging is performed. PMID:21636897

Analysis of pulsed-neutron powder diffraction patterns of the icosahedral quasicrystals Pd3Siu and AlCuLiMg (three alloys) as twinned cubic crystals with large units.

PubMed Central

Pauling, L

1991-01-01

The low-Q peaks on three pulsed-neutron powder patterns (total, U differential, and Pd differential) of the icosahedral quasicrystal Pd3SiU have been indexed on the basis of an assumed cubic structure of the crystals that by icosahedral twinning form the quasicrystal. The primitive unit cube is found to have edge length 56.20 A and to contain approximately 12,100 atoms. Similar analyses of pulsed-neutron patterns of Al55Cu10Li35, Al55Cu10Li30Mg5, and Al510Cu125Li235Mg130 give values of the cube edge length 58.3, 58.5, and 58.4 A, respectively, with approximately 11,650 atoms in the unit cube. It is suggested that the unit contains eight complexes in the beta-W positions, plus some small interstitial groups of atoms, with each complex consisting of a centered icosahedron of 13 clusters, each of 116 atoms with the icosahedral structure found in the body-centered cubic crystal Mg32(Al,Zn)49. PMID:11607201

Analysis of pulsed-neutron powder diffraction patterns of the icosahedral quasicrystals Pd3Siu and AlCuLiMg (three alloys) as twinned cubic crystals with large units.

PubMed

Pauling, L

1991-08-01

The low-Q peaks on three pulsed-neutron powder patterns (total, U differential, and Pd differential) of the icosahedral quasicrystal Pd3SiU have been indexed on the basis of an assumed cubic structure of the crystals that by icosahedral twinning form the quasicrystal. The primitive unit cube is found to have edge length 56.20 A and to contain approximately 12,100 atoms. Similar analyses of pulsed-neutron patterns of Al55Cu10Li35, Al55Cu10Li30Mg5, and Al510Cu125Li235Mg130 give values of the cube edge length 58.3, 58.5, and 58.4 A, respectively, with approximately 11,650 atoms in the unit cube. It is suggested that the unit contains eight complexes in the beta-W positions, plus some small interstitial groups of atoms, with each complex consisting of a centered icosahedron of 13 clusters, each of 116 atoms with the icosahedral structure found in the body-centered cubic crystal Mg32(Al,Zn)49.

On the kinetic and equilibrium shapes of icosahedral Al 71Pd 19Mn 10 quasicrystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Senabulya, Nancy; Xiao, Xianghui; Han, Insung

The dynamics of growth and relaxation of icosahedral single quasicrystals in a liquid phase were investigated using in situ synchrotron-based X-ray tomography. Here, our 4D studies (i.e., space- and time-resolved) provide direct evidence that indicates the growth process of an Al 71Pd 19Mn 10 quasicrystal is governed predominantly by bulk transport rather than attachment kinetics. This work is in agreement with theoretical predictions, which show that the pentagonal dodecahedron is not the minimum energy structure in Al-Pd-Mn icosahedral quasicrystals, but merely a growth shape characterized by non-zero anisotropic velocity. This transient shape transforms into a truncated dodecahedral Archimedian polyhedron oncemore » equilibrium has been attained.« less

On the kinetic and equilibrium shapes of icosahedral Al 71Pd 19Mn 10 quasicrystals

DOE PAGES

Senabulya, Nancy; Xiao, Xianghui; Han, Insung; ...

2018-03-06

The dynamics of growth and relaxation of icosahedral single quasicrystals in a liquid phase were investigated using in situ synchrotron-based X-ray tomography. Here, our 4D studies (i.e., space- and time-resolved) provide direct evidence that indicates the growth process of an Al 71Pd 19Mn 10 quasicrystal is governed predominantly by bulk transport rather than attachment kinetics. This work is in agreement with theoretical predictions, which show that the pentagonal dodecahedron is not the minimum energy structure in Al-Pd-Mn icosahedral quasicrystals, but merely a growth shape characterized by non-zero anisotropic velocity. This transient shape transforms into a truncated dodecahedral Archimedian polyhedron oncemore » equilibrium has been attained.« less

Unified structure theory of icosahedral quasicrystals: Evidence from neutron powder diffraction patterns that AlCrFeMnSi, AlCuLiMg, and TiNiFeSi icosahedral quasicrystals are twins of cubic crystals containing about 820 or 1012 atoms in a primitive unit cube

PubMed Central

Pauling, Linus

1988-01-01

A unified structure theory of icosahedral quasicrystals, combining the twinned-cubic-crystal theory and the Penrose-tiling-six-dimensional-projection theory, is described. Values of the primitive-cubic lattice constant for several quasicrystals are evaluated from x-ray and neutron diffraction data. The fact that the low-angle diffraction maxima can be indexed with cubic unit cells provides additional support for the twinned-cubic-crystal theory of icosahedral quasicrystals. PMID:16593990

Present knowledge of electronic properties and charge transport of icosahedral boron-rich solids

NASA Astrophysics Data System (ADS)

Werheit, Helmut

2009-06-01

B12 icosahedra or related structure elements determine the different modifications of elementary boron and numerous boron-rich compounds from α-rhombohedral boron with 12 to YB66 type with about 1584 atoms per unit cell. Typical are well-defined high density intrinsic defects: Jahn-Teller distorted icosahedra, vacancies, incomplete occupancies, statistical occupancies and antisite defects. The correlation between intrinsic point defects and electron deficiencies solves the discrepancy between theoretically predicted metal and experimentally proved semiconducting character. The electron deficiencies generate split-off valence states, which are decisive for the electronic transport, a superposition of band-type and hopping-type conduction. Their share depends on actual conditions like temperature or pre-excitation. The theoretical model of bipolaron hopping is incompatible with numerous experiments. Technical application of the typically p-type icosahedral boron-rich solids requires suitable n-type counterparts; doping and other possibilities are discussed.

A Vertically Flow-Following, Icosahedral Grid Model for Medium-Range and Seasonal Prediction. Part 1: Model Description

NASA Technical Reports Server (NTRS)

Bleck, Rainer; Bao, Jian-Wen; Benjamin, Stanley G.; Brown, John M.; Fiorino, Michael; Henderson, Thomas B.; Lee, Jin-Luen; MacDonald, Alexander E.; Madden, Paul; Middlecoff, Jacques;

Isolation and Characterization of Metallosphaera turreted icosahedral virus (MTIV), a founding member of a new family of archaeal viruses.

PubMed

Wagner, Cassia; Reddy, Vijay; Asturias, Francisco; Khoshouei, Maryam; Johnson, John E; Manrique, Pilar; Munson-McGee, Jacob; Baumeister, Wolfgang; Lawrence, C Martin; Young, Mark J

2017-08-02

Our understanding of archaeal virus diversity and structure is just beginning to emerge. Here we describe a new archaeal virus, tentatively named Metallosphaera turreted icosahedral virus (MTIV), that was isolated from an acidic hot spring in Yellowstone National Park, USA. Two strains of the virus were identified and found to replicate in an archaeal host species closely related to Metallosphaera yellowstonensis Each strain encodes for a 9.8-9.9 kb, linear dsDNA genome with large inverted terminal repeats. Each genome encodes for 21 ORFs. Between the strains the ORFs display high homology, but they are quite distinct from other known viral genes. The 70-nm diameter virion is built upon on a T=28 icosahedral lattice. Both single particle cryo-electron microscopy and cryo-tomography reconstructions reveal an unusual structure that has 42 turret-like projections: 12 from each of the 5-fold axes and 30 hexameric units positioned on icosahedral 2-fold axes. Both the virion structural properties and genome content support MTIV as the founding member of a new family of archaeal viruses. Importance: Many archaeal viruses are quite different than viruses infecting bacteria and eukaryotes. Initial characterization of MTIV reveals a virus distinct from other known bacterial, eukaryotic, and archaeal viruses; this finding suggests that viruses infecting Archaea are still an understudied group of viruses. As the first known virus infecting the Metallosphaera , MTIV provides a new system for exploring archaeal virology by examining host-virus interactions and the unique features of MTIV structure-function relationships. These studies will likely expand our understanding of virus ecology and evolution. Copyright © 2017 American Society for Microbiology.

Analysis of phases in the structure determination of an icosahedral virus.

PubMed

Plevka, Pavel; Kaufmann, Bärbel; Rossmann, Michael G

2011-06-01

The constraints imposed on structure-factor phases by noncrystallographic symmetry (NCS) allow phase improvement, phase extension to higher resolution and hence ab initio phase determination. The more numerous the NCS redundancy and the greater the volume used for solvent flattening, the greater the power for phase determination. In a case analyzed here the icosahedral NCS phasing appeared to have broken down, although later successful phase extension was possible when the envelope around the NCS region was tightened. The phases from the failed phase-determination attempt fell into four classes, all of which satisfied the NCS constraints. These four classes corresponded to the correct solution, opposite enantiomorph, Babinet inversion and opposite enantiomorph with Babinet inversion. These incorrect solutions can be seeded from structure factors belonging to reciprocal-space volumes that lie close to icosahedral NCS axes where the structure amplitudes tend to be large and the phases tend to be 0 or π. Furthermore, the false solutions can spread more easily if there are large errors in defining the envelope designating the region in which NCS averaging is performed. © 2011 International Union of Crystallography

Magnetism in icosahedral quasicrystals: current status and open questions

DOE PAGES

Goldman, Alan I.

2014-07-02

Progress in our understanding of the magnetic properties of R-containing icosahedral quasicrystals (R = rare earth element) from over 20 years of experimental effort is reviewed. This includes the much studied R-Mg-Zn and R-Mg-Cd ternary systems, as well as several magnetic quasicrystals that have been discovered and investigated more recently including Sc-Fe-Zn, R-Ag-In, Yb-Au-Al, the recently synthesized R-Cd binary quasicrystals, and their periodic approximants. In many ways, the magnetic properties among these quasicrystals are very similar. However, differences are observed that suggest new experiments and promising directions for future research.

Diphosphine-protected ultrasmall gold nanoclusters: opened icosahedral Au 13 and heart-shaped Au 8 clusters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Shan-Shan; Feng, Lei; Senanayake, Ravithree D.

Two ultrasmall gold clusters, Au 13 and Au 8 , were identified as a distorted I h icosahedral Au 13 and edge-shared “core + 4 exo ” structure Au 8 S 2 cores, respectively. They showed interesting luminescence and electrochemical properties.

Diphosphine-protected ultrasmall gold nanoclusters: opened icosahedral Au 13 and heart-shaped Au 8 clusters

DOE PAGES

Zhang, Shan-Shan; Feng, Lei; Senanayake, Ravithree D.; ...

2018-01-01

Two ultrasmall gold clusters, Au 13 and Au 8 , were identified as a distorted I h icosahedral Au 13 and edge-shared “core + 4 exo ” structure Au 8 S 2 cores, respectively. They showed interesting luminescence and electrochemical properties.

Studies of inactivation mechanism of non-enveloped icosahedral virus by a visible ultrashort pulsed laser

PubMed Central

2014-01-01

Background Low-power ultrashort pulsed (USP) lasers operating at wavelengths of 425 nm and near infrared region have been shown to effectively inactivate viruses such as human immunodeficiency virus (HIV), M13 bacteriophage, and murine cytomegalovirus (MCMV). It was shown previously that non-enveloped, helical viruses such as M13 bacteriophage, were inactivated by a USP laser through an impulsive stimulated Raman scattering (ISRS) process. Recently, enveloped virus like MCMV has been shown to be inactivated by a USP laser via protein aggregation induced by an ISRS process. However, the inactivation mechanism for a clinically important class of viruses – non-enveloped, icosahedral viruses remains unknown. Results and discussions We have ruled out the following four possible inactivation mechanisms for non-enveloped, icosahedral viruses, namely, (1) inactivation due to ultraviolet C (UVC) photons produced by non-linear optical process of the intense, fundamental laser beam at 425 nm; (2) inactivation caused by thermal heating generated by the direct laser absorption/heating of the virion; (3) inactivation resulting from a one-photon absorption process via chromophores such as porphyrin molecules, or indicator dyes, potentially producing reactive oxygen or other species; (4) inactivation by the USP lasers in which the extremely intense laser pulse produces shock wave-like vibrations upon impact with the viral particle. We present data which support that the inactivation mechanism for non-enveloped, icosahedral viruses is the impulsive stimulated Raman scattering process. Real-time PCR experiments show that, within the amplicon size of 273 bp tested, there is no damage on the genome of MNV-1 caused by the USP laser irradiation. Conclusion We conclude that our model non-enveloped virus, MNV-1, is inactivated by the ISRS process. These studies provide fundamental knowledge on photon-virus interactions on femtosecond time scales. From the analysis of the transmission

Studies of Inactivation Mechanism of non-enveloped icosahedral viruses by a visible ultrashort pulsed laser

USDA-ARS?s Scientific Manuscript database

The inactivation mechanism of ultrashort pulsed laser irradiation at a wavelength of 425 nm has been studied using two different-sized, non-enveloped icosahedral viruses, murine norovirus-1 (MNV-1) and human papillomavirus-16 (HPV-16) pseudovirions. Our experimental results are consistent with a mo...

Dynamic and Kinetic Assembly Studies of an Icosahedral Virus Capsid

NASA Astrophysics Data System (ADS)

Lee, Kelly

2011-03-01

Hepatitis B virus has an icosahedrally symmetrical core particle (capsid), composed of either 90 or 120 copies of a dimeric protein building block. We are using time-resolved, solution small-angle X-ray scattering and single-molecule fluorescence microscopy to probe the core particle assembly reaction at the ensemble and individual assembly levels. Our experiments to date reveal the assembly process to be highly cooperative with minimal population of stable intermediate species. Solution conditions, particularly salt concentration, appears to influence the partitioning of assembly products into the two sizes of shells. Funding from NIH R00-GM080352 and University of Washington.

Diffuse Scattering in the Icosahedral AL-Li-Cu Quasicrystal

NASA Astrophysics Data System (ADS)

Proult, A.; Donnadieu, P.; Wang, K.; Garoche, P.

1995-12-01

Electron diffraction patterns of icosahedral quasicrystals frequently exhibit diffuse scattering features. We report a detailed analysis of diffuse scattering in Al{6}Li{3}Cu (T2) quasicrystalline samples. The samples have been specifically heat-treated which allows to observe pronounced diffuse effects. Diffuse streaks are observed along the 5-fold and 2-fold symmetry axes and are elongated perpendicularly to these directions. These streaks are due to discs in the 3-dimensional reciprocal space. The diffuse disc positions are only indexable in the 6-dimensional hyperspace but the disc intensities do not agree with the ones predicted by the Cut-and-Project method. The diffuse discs we observed seem to be related to an original quasicrystalline phenomenon overlapping with the icosahedral phase. Les diagrammes de diffraction électronique des quasicristaux icosaédriques présentent fréquemment des diffusions diffuses. Nous les analysons ici en détails sur des échantillons de phase quasicristalline Al{6}Li{3}Cu (T2) traités thermiquement dans lesquels les diffusions diffuses sont trés prononcées. Les intensités diffuses forment des batônnets centrés sur des positions appartenant aux rangées réciproques d'ordre 5 et d'ordre 2 et allongés perpendiculairement à ces directions. On montre qu'il s'agit en fait de disques diffus. dans le réseau réciproque à 3 dimensions, dont les positions ne peuvent s'indexer que sur le réseau à 6 dimensions. Toutefois, les intensités ne correspondent pas à celle prédites par l'algorithme de Coupe-et-Projection. Les disques de diffusion diffuse semblent relever d'une organisation quasicristalline originale se superposant à la phase icosaédrique.

Allosteric Control of Icosahedral Capsid Assembly

PubMed Central

Lazaro, Guillermo R.

2017-01-01

During the lifecycle of a virus, viral proteins and other components self-assemble to form an ordered protein shell called a capsid. This assembly process is subject to multiple competing constraints, including the need to form a thermostable shell while avoiding kinetic traps. It has been proposed that viral assembly satisfies these constraints through allosteric regulation, including the interconversion of capsid proteins among conformations with different propensities for assembly. In this article we use computational and theoretical modeling to explore how such allostery affects the assembly of icosahedral shells. We simulate assembly under a wide range of protein concentrations, protein binding affinities, and two different mechanisms of allosteric control. We find that, above a threshold strength of allosteric control, assembly becomes robust over a broad range of subunit binding affinities and concentrations, allowing the formation of highly thermostable capsids. Our results suggest that allostery can significantly shift the range of protein binding affinities that lead to successful assembly, and thus should be accounted for in models that are used to estimate interaction parameters from experimental data. PMID:27117092

Structural evolutions and hereditary characteristics of icosahedral nano-clusters formed in Mg70Zn30 alloys during rapid solidification processes

NASA Astrophysics Data System (ADS)

Liang, Yong-Chao; Liu, Rang-Su; Xie, Quan; Tian, Ze-An; Mo, Yun-Fei; Zhang, Hai-Tao; Liu, Hai-Rong; Hou, Zhao-Yang; Zhou, Li-Li; Peng, Ping

2017-02-01

To investigate the structural evolution and hereditary mechanism of icosahedral nano-clusters formed during rapid solidification, a molecular dynamics (MD) simulation study has been performed for a system consisting of 107 atoms of liquid Mg70Zn30 alloy. Adopting Honeycutt-Anderson (HA) bond-type index method and cluster type index method (CTIM-3) to analyse the microstructures in the system it is found that for all the nano-clusters including 2~8 icosahedral clusters in the system, there are 62 kinds of geometrical structures, and those can be classified, by the configurations of the central atoms of basic clusters they contained, into four types: chain-like, triangle-tailed, quadrilateral-tailed and pyramidal-tailed. The evolution of icosahedral nano-clusters can be conducted by perfect heredity and replacement heredity, and the perfect heredity emerges when temperature is slightly less than Tm then increase rapidly and far exceeds the replacement heredity at Tg; while for the replacement heredity, there are three major modes: replaced by triangle (3-atoms), quadrangle (4-atoms) and pentagonal pyramid (6-atoms), rather than by single atom step by step during rapid solidification processes.

Curating viscoelastic properties of icosahedral viruses, virus-based nanomaterials, and protein cages.

PubMed

Kant, Ravi; Rayaprolu, Vamseedhar; McDonald, Kaitlyn; Bothner, Brian

2018-06-01

The beauty, symmetry, and functionality of icosahedral virus capsids has attracted the attention of biologists, physicists, and mathematicians ever since they were first observed. Viruses and protein cages assemble into functional architectures in a range of sizes, shapes, and symmetries. To fulfill their biological roles, these structures must self-assemble, resist stress, and are often dynamic. The increasing use of icosahedral capsids and cages in materials science has driven the need to quantify them in terms of structural properties such as rigidity, stiffness, and viscoelasticity. In this study, we employed Quartz Crystal Microbalance with Dissipation technology (QCM-D) to characterize and compare the mechanical rigidity of different protein cages and viruses. We attempted to unveil the relationships between rigidity, radius, shell thickness, and triangulation number. We show that the rigidity and triangulation numbers are inversely related to each other and the comparison of rigidity and radius also follows the same trend. Our results suggest that subunit orientation, protein-protein interactions, and protein-nucleic acid interactions are important for the resistance to deformation of these complexes, however, the relationships are complex and need to be explored further. The QCM-D based viscoelastic measurements presented here help us elucidate these relationships and show the future prospect of this technique in the field of physical virology and nano-biotechnology.

Many-molecule encapsulation by an icosahedral shell

PubMed Central

Perlmutter, Jason D; Mohajerani, Farzaneh; Hagan, Michael F

2016-01-01

We computationally study how an icosahedral shell assembles around hundreds of molecules. Such a process occurs during the formation of the carboxysome, a bacterial microcompartment that assembles around many copies of the enzymes ribulose 1,5-bisphosphate carboxylase/ oxygenase and carbonic anhydrase to facilitate carbon fixation in cyanobacteria. Our simulations identify two classes of assembly pathways leading to encapsulation of many-molecule cargoes. In one, shell assembly proceeds concomitantly with cargo condensation. In the other, the cargo first forms a dense globule; then, shell proteins assemble around and bud from the condensed cargo complex. Although the model is simplified, the simulations predict intermediates and closure mechanisms not accessible in experiments, and show how assembly can be tuned between these two pathways by modulating protein interactions. In addition to elucidating assembly pathways and critical control parameters for microcompartment assembly, our results may guide the reengineering of viruses as nanoreactors that self-assemble around their reactants. DOI: http://dx.doi.org/10.7554/eLife.14078.001 PMID:27166515

Molecular symmetry: Why permutation-inversion (PI) groups don't render the point groups obsolete

NASA Astrophysics Data System (ADS)

Groner, Peter

2018-01-01

The analysis of spectra of molecules with internal large-amplitude motions (LAMs) requires molecular symmetry (MS) groups that are larger than and significantly different from the more familiar point groups. MS groups are described often by the permutation-inversion (PI) group method. It is shown that point groups still can and should play a significant role together with the PI groups for a class of molecules with internal rotors. In molecules of this class, several simple internal rotors are attached to a rigid molecular frame. The PI groups for this class are semidirect products like H ^ F, where the invariant subgroup H is a direct product of cyclic groups and F is a point group. This result is used to derive meaningful labels for MS groups, and to derive correlation tables between MS groups and point groups. MS groups of this class have many parallels to space groups of crystalline solids.

Magnetic Resonance Characterization of Defects in Icosahedral and Cubic Boron Arsenide Bulk Crystals

NASA Astrophysics Data System (ADS)

Glaser, E. R.; Freitas, J. A., Jr.; Cress, C. D.; Perkins, F. K.; Prokes, S. M.; Ruppalt, L. B.; Culbertson, J. C.; Whiteley, C.; Edgar, J. H.; Tian, F.; Ren, Z.; Kim, J.; Shi, L.; Naval Research Lab Team; Kansas State U. Team; U. Houston Team; U. Texas Team

Low-temperature electron spin resonance (ESR) at 9.5 GHz and optically-detected magnetic resonance (ODMR) at 24 GHz were employed to investigate point defects in icosahedral and cubic Boron Arsenide bulk crystals. These semiconductors are of interest for use in high radiation and/or high temperature environments. ESR of the (001) B12As2 (Eg = 3.47 eV) mm-size platelets revealed two distinct features of unknown origin. The first signal is characterized by Zeeman splitting g-values of g|| = 2.017, g⊥ = 2.0183 while the second with g|| = 2.0182, g⊥ = 1.9997. Most notably, the second signal was also observed from ODMR on the broad 2.4 eV ``yellow/green'' photoluminescence band previously reported for these crystals and suggests its direct involvement in this likely defect-related radiative recombination process. Preliminary ESR obtained for the 100-300 micron-size cubic BAs crystals revealed a signal with g-value of 2.018 (very similar to that found for the B12As2 crystals) and broad FWHM value of 182 G. Possible origins of these defects will be discussed.

Teaching Point-Group Symmetry with Three-Dimensional Models

ERIC Educational Resources Information Center

Flint, Edward B.

2011-01-01

Three tools for teaching symmetry in the context of an upper-level undergraduate or introductory graduate course on the chemical applications of group theory are presented. The first is a collection of objects that have the symmetries of all the low-symmetry and high-symmetry point groups and the point groups with rotational symmetries from 2-fold…

Topological phases protected by point group symmetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Hao; Huang, Sheng -Jie; Fu, Liang

We consider symmetry-protected topological (SPT) phases with crystalline point group symmetry, dubbed point group SPT (pgSPT) phases. We show that such phases can be understood in terms of lower-dimensional topological phases with on-site symmetry and that they can be constructed as stacks and arrays of these lower-dimensional states. This provides the basis for a general framework to classify and characterize bosonic and fermionic pgSPT phases, which can be applied for arbitrary crystalline point group symmetry and in arbitrary spatial dimensions. We develop and illustrate this framework by means of a few examples, focusing on three-dimensional states. We classify bosonic pgSPTmore » phases and fermionic topological crystalline superconductors with Z P 2 (reflection) symmetry, electronic topological crystalline insulators (TCIs) with U(1)×Z P 2 symmetry, and bosonic pgSPT phases with C 2v symmetry, which is generated by two perpendicular mirror reflections. We also study surface properties, with a focus on gapped, topologically ordered surface states. For electronic TCIs, we find a Z 8 × Z 2 classification, where the Z 8 corresponds to known states obtained from noninteracting electrons, and the Z 2 corresponds to a “strongly correlated” TCI that requires strong interactions in the bulk. Lastly, our approach may also point the way toward a general theory of symmetry-enriched topological phases with crystalline point group symmetry.« less

Analytical and computational modeling of early penetration of non-enveloped icosahedral viruses into cells.

PubMed

Katzengold, Rona; Zaharov, Evgeniya; Gefen, Amit

2016-07-27

As obligate intracellular parasites, all viruses penetrate target cells to initiate replication and infection. This study introduces two approaches for evaluating the contact loads applied to a cell during early penetration of non-enveloped icosahedral viruses. The first approach is analytical modeling which is based on Hertz's theory for the contact of two elastic bodies; here we model the virus capsid as a triangle and the cell as an order-of-magnitude larger sphere. The second approach is finite element modeling, where we simulate three types of viruses: adeno-, papilloma- and polio- viruses, each interacting with a cell section. We find that the peak contact pressures and forces generated at the initial virus-cell contact depend on the virus geometry - that is both size and shape. With respect to shape, we show that the icosahedral virus shape induces greater peak pressures compared to a spherical virus shape. With respect to size, it is shown that the larger the virus is the greater are the contact loads in the attacked cell. Utilization of our modeling can be substantially useful not only for basic science studies, but also in other, more applied fields, such as in the field of gene therapy, or in `phage' virus studies.

Quantum transport through single and multilayer icosahedral fullerenes

NASA Astrophysics Data System (ADS)

Lovey, Daniel A.; Romero, Rodolfo H.

2013-10-01

We use a tight-binding Hamiltonian and Green functions methods to calculate the quantum transmission through single-wall fullerenes and bilayered and trilayered onions of icosahedral symmetry attached to metallic leads. The electronic structure of the onion-like fullerenes takes into account the curvature and finite size of the fullerenes layers as well as the strength of the intershell interactions depending on to the number of interacting atom pairs belonging to adjacent shells. Misalignment of the symmetry axes of the concentric iscosahedral shells produces breaking of the level degeneracies of the individual shells, giving rise some narrow quasi-continuum bands instead of the localized discrete peaks of the individual fullerenes. As a result, the transmission function for non symmetrical onions is rapidly varying functions of the Fermi energy. Furthermore, we found that most of the features of the transmission through the onions are due to the electronic structure of the outer shell with additional Fano-like antiresonances arising from coupling with or between the inner shells.

Adding the Third Dimension to Virus Life Cycles: Three-Dimensional Reconstruction of Icosahedral Viruses from Cryo-Electron Micrographs

PubMed Central

Baker, T. S.; Olson, N. H.; Fuller, S. D.

1999-01-01

Viruses are cellular parasites. The linkage between viral and host functions makes the study of a viral life cycle an important key to cellular functions. A deeper understanding of many aspects of viral life cycles has emerged from coordinated molecular and structural studies carried out with a wide range of viral pathogens. Structural studies of viruses by means of cryo-electron microscopy and three-dimensional image reconstruction methods have grown explosively in the last decade. Here we review the use of cryo-electron microscopy for the determination of the structures of a number of icosahedral viruses. These studies span more than 20 virus families. Representative examples illustrate the use of moderate- to low-resolution (7- to 35-Å) structural analyses to illuminate functional aspects of viral life cycles including host recognition, viral attachment, entry, genome release, viral transcription, translation, proassembly, maturation, release, and transmission, as well as mechanisms of host defense. The success of cryo-electron microscopy in combination with three-dimensional image reconstruction for icosahedral viruses provides a firm foundation for future explorations of more-complex viral pathogens, including the vast number that are nonspherical or nonsymmetrical. PMID:10585969

Multiple diffraction in an icosahedral Al-Cu-Fe quasicrystal

NASA Astrophysics Data System (ADS)

Fan, C. Z.; Weber, Th.; Deloudi, S.; Steurer, W.

2011-07-01

In order to reveal its influence on quasicrystal structure analysis, multiple diffraction (MD) effects in an icosahedral Al-Cu-Fe quasicrystal have been investigated in-house on an Oxford Diffraction four-circle diffractometer equipped with an Onyx™ CCD area detector and MoKα radiation. For that purpose, an automated approach for Renninger scans (ψ-scans) has been developed. Two weak reflections were chosen as the main reflections (called P) in the present measurements. As is well known for periodic crystals, it is also observed for this quasicrystal that the intensity of the main reflection may significantly increase if the simultaneous (H) and the coupling (P-H) reflections are both strong, while there is no obvious MD effect if one of them is weak. The occurrence of MD events during ψ-scans has been studied based on an ideal structure model and the kinematical MD theory. The reliability of the approach is revealed by the good agreement between simulation and experiment. It shows that the multiple diffraction effect is quite significant.

Renormalization group fixed points of foliated gravity-matter systems

NASA Astrophysics Data System (ADS)

Biemans, Jorn; Platania, Alessia; Saueressig, Frank

2017-05-01

We employ the Arnowitt-Deser-Misner formalism to study the renormalization group flow of gravity minimally coupled to an arbitrary number of scalar, vector, and Dirac fields. The decomposition of the gravitational degrees of freedom into a lapse function, shift vector, and spatial metric equips spacetime with a preferred (Euclidean) "time"- direction. In this work, we provide a detailed derivation of the renormalization group flow of Newton's constant and the cosmological constant on a flat Friedmann-Robertson-Walker background. Adding matter fields, it is shown that their contribution to the flow is the same as in the covariant formulation and can be captured by two parameters d g d λ . We classify the resulting fixed point structure as a function of these parameters finding that the existence of non-Gaussian renormalization group fixed points is rather generic. In particular the matter content of the standard model and its most common extensions gives rise to one non-Gaussian fixed point with real critical exponents suitable for Asymptotic Safety. Moreover, we find non-Gaussian fixed points for any number of scalar matter fields, making the scenario attractive for cosmological model building.

Icosahedral quasicrystalline (Ti1.6V0.4Ni)100-xScx alloys: Synthesis, structure and their application in Ni-MH batteries

NASA Astrophysics Data System (ADS)

Hu, Wen; Yi, Jianhong; Zheng, Biju; Wang, Limin

2013-06-01

Thanks to the revolutionary discovery of 5-fold symmetry contributed by Shechtman, quasicrystal is now recognized as another solid-state existing form. As the second largest class of quasicrystals, titanium-based icosahedral quasicrystals are very promising for hydrogen storage applications owing to their inherent abundant interstitial sites and favorable hydrogen-metal chemistry. In this context, (Ti1.6V0.4Ni)100-xScx (x=0.5-6) quaternary icosahedral quasicrystals have been successfully synthesized via arc-melting and subsequent melt-spinning techniques, and then their electrochemical performance toward hydrogen is explored. When the molar ratio of Sc addition is under 1%, a maximum discharge capacity of about 270 mA h g-1 can be delivered. With further increasing Sc amount to 6%, good cycling stability as well as significantly retarded self-discharge rate (capacity retention 94% after 24 h relaxation) is observed. But meanwhile, the discharge capacities fall into 250-240 mA h g-1, and the electrocatalytic activity improvement is highly demanded.

Atomistic modeling of the low-frequency mechanical modes and Raman spectra of icosahedral virus capsids

NASA Astrophysics Data System (ADS)

Dykeman, Eric C.; Sankey, Otto F.

2010-02-01

We describe a technique for calculating the low-frequency mechanical modes and frequencies of a large symmetric biological molecule where the eigenvectors of the Hessian matrix are determined with full atomic detail. The method, which follows order N methods used in electronic structure theory, determines the subset of lowest-frequency modes while using group theory to reduce the complexity of the problem. We apply the method to three icosahedral viruses of various T numbers and sizes; the human viruses polio and hepatitis B, and the cowpea chlorotic mottle virus, a plant virus. From the normal-mode eigenvectors, we use a bond polarizability model to predict a low-frequency Raman scattering profile for the viruses. The full atomic detail in the displacement patterns combined with an empirical potential-energy model allows a comparison of the fully atomic normal modes with elastic network models and normal-mode analysis with only dihedral degrees of freedom. We find that coarse-graining normal-mode analysis (particularly the elastic network model) can predict the displacement patterns for the first few (˜10) low-frequency modes that are global and cooperative.

Deciphering the kinetic mechanism of spontaneous self-assembly of icosahedral capsids.

PubMed

Nguyen, Hung D; Reddy, Vijay S; Brooks, Charles L

2007-02-01

Self-assembly of viral proteins into icosahedral capsids is an interesting yet poorly understood phenomenon of which elucidation may aid the exploration of beneficial applications of capsids in materials science and medicine. Using molecular dynamics simulations of coarse-grained models for capsid proteins, we show that the competition between the formation of full capsids and nonidealized structures is strongly dependent upon the protein concentration and temperature, occurring kinetically as a cascade of elementary reactions in which free monomers are added to the growing oligomers on a downhill free-energy landscape. However, the insertion of the final subunits is the rate-limiting, energetically unfavorable step in viral capsid assembly. A phase diagram has been constructed to show the regions where capsids or nonidealized structures are stable at each concentration and temperature. We anticipate that our findings will provide guidance in identifying suitable conditions required for in vitro viral capsid assembly experiments.

Point Groups Based on Methane and Adamantane (Td) Skeletons.

ERIC Educational Resources Information Center

Fujita, Shinsaku

1986-01-01

Describes a procedure for constructing point groups based on the symmetric parent molecules of methane and adamantane. Intended for use in teaching concepts such as subgroups and cosets to beginners in group theory. (TW)

Al-centered icosahedral ordering in Cu46Zr46Al8 bulk metallic glass

NASA Astrophysics Data System (ADS)

Fang, H. Z.; Hui, X.; Chen, G. L.; Liu, Z. K.

2009-03-01

Icosahedral short-range order, of which Al atoms are caged in the center of icosahedra with Cu and Zr atoms being the vertices, has been evidenced in the Cu46Zr46Al8 glassy structure by ab initio molecular dynamics simulation. These Al-centered clusters distribute irregularly in the three-dimensional space and form a "backbone" structure of the Cu46Zr46Al8 glass alloy. It is suggested that this kind of local structural feature is attributed to the requirement of efficient dense packing and the chemical affinity between Zr-Zr, Zr-Al, and Cu-Zr atoms. Our calculated results are found to be in good agreement with the experimental data.

Thirty-thousand-year-old distant relative of giant icosahedral DNA viruses with a pandoravirus morphology

PubMed Central

Legendre, Matthieu; Bartoli, Julia; Shmakova, Lyubov; Jeudy, Sandra; Labadie, Karine; Adrait, Annie; Lescot, Magali; Poirot, Olivier; Bertaux, Lionel; Bruley, Christophe; Couté, Yohann; Rivkina, Elizaveta; Abergel, Chantal; Claverie, Jean-Michel

2014-01-01

The largest known DNA viruses infect Acanthamoeba and belong to two markedly different families. The Megaviridae exhibit pseudo-icosahedral virions up to 0.7 μm in diameter and adenine–thymine (AT)-rich genomes of up to 1.25 Mb encoding a thousand proteins. Like their Mimivirus prototype discovered 10 y ago, they entirely replicate within cytoplasmic virion factories. In contrast, the recently discovered Pandoraviruses exhibit larger amphora-shaped virions 1 μm in length and guanine–cytosine-rich genomes up to 2.8 Mb long encoding up to 2,500 proteins. Their replication involves the host nucleus. Whereas the Megaviridae share some general features with the previously described icosahedral large DNA viruses, the Pandoraviruses appear unrelated to them. Here we report the discovery of a third type of giant virus combining an even larger pandoravirus-like particle 1.5 μm in length with a surprisingly smaller 600 kb AT-rich genome, a gene content more similar to Iridoviruses and Marseillevirus, and a fully cytoplasmic replication reminiscent of the Megaviridae. This suggests that pandoravirus-like particles may be associated with a variety of virus families more diverse than previously envisioned. This giant virus, named Pithovirus sibericum, was isolated from a >30,000-y-old radiocarbon-dated sample when we initiated a survey of the virome of Siberian permafrost. The revival of such an ancestral amoeba-infecting virus used as a safe indicator of the possible presence of pathogenic DNA viruses, suggests that the thawing of permafrost either from global warming or industrial exploitation of circumpolar regions might not be exempt from future threats to human or animal health. PMID:24591590

Thirty-thousand-year-old distant relative of giant icosahedral DNA viruses with a pandoravirus morphology.

PubMed

Legendre, Matthieu; Bartoli, Julia; Shmakova, Lyubov; Jeudy, Sandra; Labadie, Karine; Adrait, Annie; Lescot, Magali; Poirot, Olivier; Bertaux, Lionel; Bruley, Christophe; Couté, Yohann; Rivkina, Elizaveta; Abergel, Chantal; Claverie, Jean-Michel

2014-03-18

The largest known DNA viruses infect Acanthamoeba and belong to two markedly different families. The Megaviridae exhibit pseudo-icosahedral virions up to 0.7 μm in diameter and adenine-thymine (AT)-rich genomes of up to 1.25 Mb encoding a thousand proteins. Like their Mimivirus prototype discovered 10 y ago, they entirely replicate within cytoplasmic virion factories. In contrast, the recently discovered Pandoraviruses exhibit larger amphora-shaped virions 1 μm in length and guanine-cytosine-rich genomes up to 2.8 Mb long encoding up to 2,500 proteins. Their replication involves the host nucleus. Whereas the Megaviridae share some general features with the previously described icosahedral large DNA viruses, the Pandoraviruses appear unrelated to them. Here we report the discovery of a third type of giant virus combining an even larger pandoravirus-like particle 1.5 μm in length with a surprisingly smaller 600 kb AT-rich genome, a gene content more similar to Iridoviruses and Marseillevirus, and a fully cytoplasmic replication reminiscent of the Megaviridae. This suggests that pandoravirus-like particles may be associated with a variety of virus families more diverse than previously envisioned. This giant virus, named Pithovirus sibericum, was isolated from a >30,000-y-old radiocarbon-dated sample when we initiated a survey of the virome of Siberian permafrost. The revival of such an ancestral amoeba-infecting virus used as a safe indicator of the possible presence of pathogenic DNA viruses, suggests that the thawing of permafrost either from global warming or industrial exploitation of circumpolar regions might not be exempt from future threats to human or animal health.

Semiconducting icosahedral boron arsenide crystal growth for neutron detection

NASA Astrophysics Data System (ADS)

Whiteley, C. E.; Zhang, Y.; Gong, Y.; Bakalova, S.; Mayo, A.; Edgar, J. H.; Kuball, M.

2011-03-01

Semiconducting icosahedral boron arsenide, B12As2, is an excellent candidate for neutron detectors, thermoelectric converters, and radioisotope batteries, for which high quality single crystals are required. Thus, the present study was undertaken to grow B12As2 crystals by precipitation from metal solutions (nickel) saturated with elemental boron (or B12As2 powder) and arsenic in a sealed quartz ampoule. B12As2 crystals of 10-15 mm were produced when a homogeneous mixture of the three elements was held at 1150 °C for 48-72 h and slowly cooled (3.5 °C/h). The crystals varied in color and transparency from black and opaque to clear and transparent. X-ray topography (XRT), and elemental analysis by energy dispersive X-ray spectroscopy (EDS) confirmed that the crystals had the expected rhombohedral structure and chemical stoichiometry. The concentrations of residual impurities (nickel, carbon, etc.) were low, as measured by Raman spectroscopy and secondary ion mass spectrometry (SIMS). Additionally, low etch-pit densities (4.4×107 cm-2) were observed after etching in molten KOH at 500 °C. Thus, the flux growth method is viable for growing large, high-quality B12As2 crystals.

Cooperative Jahn-Teller phase transition of icosahedral molecular units

NASA Astrophysics Data System (ADS)

Nasrollahi, Seyed H.; Vvedensky, Dimitri D.

2017-02-01

Non-linear molecules undergo distortions when the orbital degeneracy of the highest occupied level is lifted by the Jahn-Teller effect. If such molecules or clusters of atoms are coupled to one another, the system may experience a cooperative Jahn-Teller effect (CJTE). In this paper, we describe a model of how the CJTE leads to the crystallization of the disordered phase. The model Hamiltonian is based on a normal mode decomposition of the clusters in order to maintain the symmetry labels. We take account of the electron-strain and the electron-phonon couplings and, by displacing the coordinates of the oscillators, obtain a term that explicitly couples the Jahn-Teller centers, enabling us to perform a mean-field analysis. The calculation of the free energy then becomes straightforward, and obtaining phase diagrams in various regimes follows from the minimization of this free energy. The results show that the character of the phase transition may change from strong to weak first order and even to second-order, depending on the coupling to the vibrational modes. Taken together, these results may serve as a paradigm for crystallization near the transition temperature, where the atoms tend to form clusters of icosahedral symmetry.

Symmetrical polyhedra (simple crystal forms) as orbits of noncrystallographic point symmetry groups

NASA Astrophysics Data System (ADS)

Ovsetsina, T. I.; Chuprunov, E. V.

2017-09-01

Simple crystal forms are analyzed as the orbits of noncrystallographic point symmetry groups on a set of smooth or structured ("hatched") planes of crystal space. Polyhedra with symmetrically equivalent faces, obtained using noncrystallographic point symmetry groups, are considered. All possible versions of simple forms for all noncrystallographic groups are listed in a unified table.

Icosahedral quasicrystalline (Ti₁.₆V₀.₄Ni)₁₀₀₋xScx alloys: Synthesis, structure and their application in Ni-MH batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, Wen; State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, CAS, Changchun 130022, Jilin; Yi, Jianhong

2013-06-01

Thanks to the revolutionary discovery of 5-fold symmetry contributed by Shechtman, quasicrystal is now recognized as another solid-state existing form. As the second largest class of quasicrystals, titanium-based icosahedral quasicrystals are very promising for hydrogen storage applications owing to their inherent abundant interstitial sites and favorable hydrogen-metal chemistry. In this context, (Ti₁.₆V₀.₄Ni)₁₀₀₋xScx (x=0.5–6) quaternary icosahedral quasicrystals have been successfully synthesized via arc-melting and subsequent melt-spinning techniques, and then their electrochemical performance toward hydrogen is explored. When the molar ratio of Sc addition is under 1%, a maximum discharge capacity of about 270 mA h g⁻¹ can be delivered. With furthermore » increasing Sc amount to 6%, good cycling stability as well as significantly retarded self-discharge rate (capacity retention 94% after 24 h relaxation) is observed. But meanwhile, the discharge capacities fall into 250-240 mA h g⁻¹, and the electrocatalytic activity improvement is highly demanded. - Graphical abstract: Quasicrystalline Ti–V–Ni–Sc hydrogen storage materials: Sc addition into Ti₁.₆V₀.₄Ni alloy forms the icosahedral phase (see picture). With optimal Sc dosage, the anodic cycling stability and self-discharge property are greatly enhanced. - Highlights: • Crystalline disallowed 5-fold symmetry is present in (Ti₁.₆V₀.₄Ni)₁₀₀₋xScx alloys. • Ti-based metastable quasicrystalline alloys can store hydrogen electrochemically. • A maximum discharge capacity of 270 mA h g⁻¹ can be delivered. • Advantageous cycle stability and self-discharge property benefit from Sc addition. • Ti and V dissolution is suppressed by an oxide layer resulting from Sc corrosion.« less

Axial point groups: rank 1, 2, 3 and 4 property tensor tables.

PubMed

Litvin, Daniel B

2015-05-01

The form of a physical property tensor of a quasi-one-dimensional material such as a nanotube or a polymer is determined from the material's axial point group. Tables of the form of rank 1, 2, 3 and 4 property tensors are presented for a wide variety of magnetic and non-magnetic tensor types invariant under each point group in all 31 infinite series of axial point groups. An application of these tables is given in the prediction of the net polarization and magnetic-field-induced polarization in a one-dimensional longitudinal conical magnetic structure in multiferroic hexaferrites.

Quasicrystals at extreme conditions: The role of pressure in stabilizing icosahedral Al 63Cu 24Fe 13 at high temperature

DOE PAGES

Stagno, Vincenzo; Bindi, Luca; Park, Changyong; ...

2015-11-20

Icosahedrite, the first natural quasicrystal with composition Al 63Cu 24Fe 13, was discovered in several grains of the Khatyrka meteorite, a unique CV3 carbonaceous chondrite. The presence in the meteorite fragments of icosahedrite strictly associated with high-pressure phases like ahrensite and stishovite indicates a formation conditions at high pressures and temperatures, likely during an impact-induced shock occurred in contact with the reducing solar nebula gas. In contrast, previous experimental studies on the stability of synthetic icosahedral AlCuFe, which were limited to ambient pressure, indicated incongruent melting at ~1123 K, while high-pressure experiments carried out at room temperature showed structural stabilitymore » up to about 35 GPa. These data are insufficient to experimentally constrain the formation and stability of icosahedrite under extreme conditions. Here we present the results of in situ high pressure experiments using diamond anvil cells of the compressional behavior of synthetic icosahedrite up to ~50 GPa at room temperature. Simultaneous high P-T experiments have been also carried out using both laser-heated diamond anvil cells combined with in situ synchrotron X-ray diffraction (at ~42 GPa) and multi-anvil apparatus (at 21 GPa) to investigate the structural evolution of icosahedral Al 63Cu 24Fe 13 and crystallization of possible coexisting phases. The results demonstrate that the quasiperiodic symmetry of icosahedrite is retained over the entire experimental pressure range explored. In addition, we show that pressure acts to stabilize the icosahedral symmetry at temperatures much higher than previously reported. Based on our experimental study, direct crystallization of Al-Cu-Fe quasicrystals from an unusual Al-Cu-rich melt would be possible but limited to a narrow temperature range beyond which crystalline phases would form, like those observed in the Khatyrka meteorite. Here, an alternative mechanism would consist in late

Discovering Symmetry in Everyday Environments: A Creative Approach to Teaching Symmetry and Point Groups

ERIC Educational Resources Information Center

Fuchigami, Kei; Schrandt, Matthew; Miessler, Gary L.

2016-01-01

A hands-on symmetry project is proposed as an innovative way of teaching point groups to undergraduate chemistry students. Traditionally, courses teaching symmetry require students to identify the point group of a given object. This project asks the reverse: students are instructed to identify an object that matches each point group. Doing so…

Modified Stereographic Projections of Point Groups and Diagrams of Their Irreducible Representations

NASA Astrophysics Data System (ADS)

Kettle, Sidney F. A.

1999-05-01

Modified versions of the stereographic projections of the point groups of classical crystallography are presented. They show the consequences of symmetry operations rather than emphasizing the existence of symmetry elements. These projections may be used to give pictures of the irreducible representations of point groups and several examples are given. Such pictures add physical reality to the irreducible representations and facilitate simple lecture demonstration of many important aspects and applications of group theory in chemistry.

Robust group-wise rigid registration of point sets using t-mixture model

NASA Astrophysics Data System (ADS)

Ravikumar, Nishant; Gooya, Ali; Frangi, Alejandro F.; Taylor, Zeike A.

2016-03-01

A probabilistic framework for robust, group-wise rigid alignment of point-sets using a mixture of Students t-distribution especially when the point sets are of varying lengths, are corrupted by an unknown degree of outliers or in the presence of missing data. Medical images (in particular magnetic resonance (MR) images), their segmentations and consequently point-sets generated from these are highly susceptible to corruption by outliers. This poses a problem for robust correspondence estimation and accurate alignment of shapes, necessary for training statistical shape models (SSMs). To address these issues, this study proposes to use a t-mixture model (TMM), to approximate the underlying joint probability density of a group of similar shapes and align them to a common reference frame. The heavy-tailed nature of t-distributions provides a more robust registration framework in comparison to state of the art algorithms. Significant reduction in alignment errors is achieved in the presence of outliers, using the proposed TMM-based group-wise rigid registration method, in comparison to its Gaussian mixture model (GMM) counterparts. The proposed TMM-framework is compared with a group-wise variant of the well-known Coherent Point Drift (CPD) algorithm and two other group-wise methods using GMMs, using both synthetic and real data sets. Rigid alignment errors for groups of shapes are quantified using the Hausdorff distance (HD) and quadratic surface distance (QSD) metrics.

Providing nearest neighbor point-to-point communications among compute nodes of an operational group in a global combining network of a parallel computer

DOEpatents

Archer, Charles J.; Faraj, Ahmad A.; Inglett, Todd A.; Ratterman, Joseph D.

2012-10-23

Methods, apparatus, and products are disclosed for providing nearest neighbor point-to-point communications among compute nodes of an operational group in a global combining network of a parallel computer, each compute node connected to each adjacent compute node in the global combining network through a link, that include: identifying each link in the global combining network for each compute node of the operational group; designating one of a plurality of point-to-point class routing identifiers for each link such that no compute node in the operational group is connected to two adjacent compute nodes in the operational group with links designated for the same class routing identifiers; and configuring each compute node of the operational group for point-to-point communications with each adjacent compute node in the global combining network through the link between that compute node and that adjacent compute node using that link's designated class routing identifier.

Sheet-like assemblies of spherical particles with point-symmetrical patches.

PubMed

Mani, Ethayaraja; Sanz, Eduardo; Roy, Soumyajit; Dijkstra, Marjolein; Groenewold, Jan; Kegel, Willem K

2012-04-14

We report a computational study on the spontaneous self-assembly of spherical particles into two-dimensional crystals. The experimental observation of such structures stabilized by spherical objects appeared paradoxical so far. We implement patchy interactions with the patches point-symmetrically (icosahedral and cubic) arranged on the surface of the particle. In these conditions, preference for self-assembly into sheet-like structures is observed. We explain our findings in terms of the inherent symmetry of the patches and the competition between binding energy and vibrational entropy. The simulation results explain why hollow spherical shells observed in some Keplerate-type polyoxometalates (POM) appear. Our results also provide an explanation for the experimentally observed layer-by-layer growth of apoferritin--a quasi-spherical protein.

Surface field theories of point group symmetry protected topological phases

NASA Astrophysics Data System (ADS)

Huang, Sheng-Jie; Hermele, Michael

2018-02-01

We identify field theories that describe the surfaces of three-dimensional bosonic point group symmetry protected topological (pgSPT) phases. The anomalous nature of the surface field theories is revealed via a dimensional reduction argument. Specifically, we study three different surface field theories. The first field theory is quantum electrodynamics in three space-time dimensions (QED3) with four flavors of fermions. We show this theory can describe the surfaces of a majority of bosonic pgSPT phases protected by a single mirror reflection, or by Cn v point group symmetry for n =2 ,3 ,4 ,6 . The second field theory is a variant of QED3 with charge-1 and charge-3 Dirac fermions. This field theory can describe the surface of a reflection symmetric pgSPT phase built by placing an E8 state on the mirror plane. The third field theory is an O (4 ) nonlinear sigma model with a topological theta term at θ =π , or, equivalently, a noncompact CP1 model. Using a coupled wire construction, we show this is a surface theory for bosonic pgSPT phases with U (1 ) ×Z2P symmetry. For the latter two field theories, we discuss the connection to gapped surfaces with topological order. Moreover, we conjecture that the latter two field theories can describe surfaces of more general bosonic pgSPT phases with Cn v point group symmetry.

Proteomic Analysis of Sulfolobus solfataricus During Sulfolobus Turreted Icosahedral Virus Infection

PubMed Central

Maaty, Walid S.; Selvig, Kyla; Ryder, Stephanie; Tarlykov, Pavel; Hilmer, Jonathan K.; Heinemann, Joshua; Steffens, Joseph; Snyder, Jamie C.; Ortmann, Alice C.; Movahed, Navid; Spicka, Kevin; Chetia, Lakshindra; Grieco, Paul A.; Dratz, Edward A.; Douglas, Trevor; Young, Mark J.; Bothner, Brian

2012-01-01

Where there is life, there are viruses. The impact of viruses on evolution, global nutrient cycling, and disease has driven research on their cellular and molecular biology. Knowledge exists for a wide range of viruses, however, a major exception are viruses with archaeal hosts. Archaeal virus-host systems are of great interest because they have similarities to both eukaryotic and bacterial systems and often live in extreme environments. Here we report the first proteomics-based experiments on archaeal host response to viral infection. Sulfolobus Turreted Icosahedral Virus (STIV) infection of Sulfolobus solfataricus P2 was studied using 1D and 2D differential gel electrophoresis (DIGE) to measure abundance and redox changes. Cysteine reactivity was measured using novel fluorescent zwitterionic chemical probes that, together with abundance changes, suggest that virus and host are both vying for control of redox status in the cells. Proteins from nearly 50% of the predicted viral open reading frames were found along with a new STIV protein with a homolog in STIV2. This study provides insight to features of viral replication novel to the archaea, makes strong connections to well described mechanisms used by eukaryotic viruses such as ESCRT-III mediated transport, and emphasizes the complementary nature of different omics approaches. PMID:22217245

Development of a genetic system for the archaeal virus Sulfolobus turreted icosahedral virus (STIV).

PubMed

Wirth, Jennifer Fulton; Snyder, Jamie C; Hochstein, Rebecca A; Ortmann, Alice C; Willits, Deborah A; Douglas, Trevor; Young, Mark J

2011-06-20

Our understanding of archaeal viruses has been limited by the lack of genetic systems for examining viral function. We describe the construction of an infectious clone for the archaeal virus Sulfolobus turreted icosahedral virus (STIV). STIV was isolated from a high temperature (82°C) acidic (pH 2.2) hot spring in Yellowstone National Park and replicates in the archaeal model organism Sulfolobus solfataricus (Rice et al., 2004). While STIV is one of most studied archaeal viruses, little is known about its replication cycle. The development of an STIV infectious clone allows for directed gene disruptions and detailed genetic analysis of the virus. The utility of the STIV infectious clone was demonstrated by gene disruption of STIV open reading frame (ORF) B116 which resulted in crippled virus replication, while disruption of ORFs A197, C381 and B345 was lethal for virus replication. Copyright © 2011. Published by Elsevier Inc.

Sulfolobus turreted icosahedral virus c92 protein responsible for the formation of pyramid-like cellular lysis structures.

PubMed

Snyder, Jamie C; Brumfield, Susan K; Peng, Nan; She, Qunxin; Young, Mark J

2011-07-01

Host cells infected by Sulfolobus turreted icosahedral virus (STIV) have been shown to produce unusual pyramid-like structures on the cell surface. These structures represent a virus-induced lysis mechanism that is present in Archaea and appears to be distinct from the holin/endolysin system described for DNA bacteriophages. This study investigated the STIV gene products required for pyramid formation in its host Sulfolobus solfataricus. Overexpression of STIV open reading frame (ORF) c92 in S. solfataricus alone is sufficient to produce the pyramid-like lysis structures in cells. Gene disruption of c92 within STIV demonstrates that c92 is an essential protein for virus replication. Immunolocalization of c92 shows that the protein is localized to the cellular membranes forming the pyramid-like structures.

Wavelet data compression for archiving high-resolution icosahedral model data

NASA Astrophysics Data System (ADS)

Wang, N.; Bao, J.; Lee, J.

2011-12-01

With the increase of the resolution of global circulation models, it becomes ever more important to develop highly effective solutions to archive the huge datasets produced by those models. While lossless data compression guarantees the accuracy of the restored data, it can only achieve limited reduction of data size. Wavelet transform based data compression offers significant potentials in data size reduction, and it has been shown very effective in transmitting data for remote visualizations. However, for data archive purposes, a detailed study has to be conducted to evaluate its impact to the datasets that will be used in further numerical computations. In this study, we carried out two sets of experiments for both summer and winter seasons. An icosahedral grid weather model and a highly efficient wavelet data compression software were used for this study. Initial conditions were compressed and input to the model to run to 10 days. The forecast results were then compared to those forecast results from the model run with the original uncompressed initial conditions. Several visual comparisons, as well as the statistics of numerical comparisons are presented. These results indicate that with specified minimum accuracy losses, wavelet data compression achieves significant data size reduction, and at the same time, it maintains minimum numerical impacts to the datasets. In addition, some issues are discussed to increase the archive efficiency while retaining a complete set of meta data for each archived file.

Parallel point-multiplication architecture using combined group operations for high-speed cryptographic applications.

PubMed

Hossain, Md Selim; Saeedi, Ehsan; Kong, Yinan

2017-01-01

In this paper, we propose a novel parallel architecture for fast hardware implementation of elliptic curve point multiplication (ECPM), which is the key operation of an elliptic curve cryptography processor. The point multiplication over binary fields is synthesized on both FPGA and ASIC technology by designing fast elliptic curve group operations in Jacobian projective coordinates. A novel combined point doubling and point addition (PDPA) architecture is proposed for group operations to achieve high speed and low hardware requirements for ECPM. It has been implemented over the binary field which is recommended by the National Institute of Standards and Technology (NIST). The proposed ECPM supports two Koblitz and random curves for the key sizes 233 and 163 bits. For group operations, a finite-field arithmetic operation, e.g. multiplication, is designed on a polynomial basis. The delay of a 233-bit point multiplication is only 3.05 and 3.56 μs, in a Xilinx Virtex-7 FPGA, for Koblitz and random curves, respectively, and 0.81 μs in an ASIC 65-nm technology, which are the fastest hardware implementation results reported in the literature to date. In addition, a 163-bit point multiplication is also implemented in FPGA and ASIC for fair comparison which takes around 0.33 and 0.46 μs, respectively. The area-time product of the proposed point multiplication is very low compared to similar designs. The performance ([Formula: see text]) and Area × Time × Energy (ATE) product of the proposed design are far better than the most significant studies found in the literature.

Imaging and Quantitation of a Succession of Transient Intermediates Reveal the Reversible Self-Assembly Pathway of a Simple Icosahedral Virus Capsid.

PubMed

Medrano, María; Fuertes, Miguel Ángel; Valbuena, Alejandro; Carrillo, Pablo J P; Rodríguez-Huete, Alicia; Mateu, Mauricio G

2016-11-30

Understanding the fundamental principles underlying supramolecular self-assembly may facilitate many developments, from novel antivirals to self-organized nanodevices. Icosahedral virus particles constitute paradigms to study self-assembly using a combination of theory and experiment. Unfortunately, assembly pathways of the structurally simplest virus capsids, those more accessible to detailed theoretical studies, have been difficult to study experimentally. We have enabled the in vitro self-assembly under close to physiological conditions of one of the simplest virus particles known, the minute virus of mice (MVM) capsid, and experimentally analyzed its pathways of assembly and disassembly. A combination of electron microscopy and high-resolution atomic force microscopy was used to structurally characterize and quantify a succession of transient assembly and disassembly intermediates. The results provided an experiment-based model for the reversible self-assembly pathway of a most simple (T = 1) icosahedral protein shell. During assembly, trimeric capsid building blocks are sequentially added to the growing capsid, with pentamers of building blocks and incomplete capsids missing one building block as conspicuous intermediates. This study provided experimental verification of many features of self-assembly of a simple T = 1 capsid predicted by molecular dynamics simulations. It also demonstrated atomic force microscopy imaging and automated analysis, in combination with electron microscopy, as a powerful single-particle approach to characterize at high resolution and quantify transient intermediates during supramolecular self-assembly/disassembly reactions. Finally, the efficient in vitro self-assembly achieved for the oncotropic, cell nucleus-targeted MVM capsid may facilitate its development as a drug-encapsidating nanoparticle for anticancer targeted drug delivery.

Parallel point-multiplication architecture using combined group operations for high-speed cryptographic applications

PubMed Central

Saeedi, Ehsan; Kong, Yinan

2017-01-01

In this paper, we propose a novel parallel architecture for fast hardware implementation of elliptic curve point multiplication (ECPM), which is the key operation of an elliptic curve cryptography processor. The point multiplication over binary fields is synthesized on both FPGA and ASIC technology by designing fast elliptic curve group operations in Jacobian projective coordinates. A novel combined point doubling and point addition (PDPA) architecture is proposed for group operations to achieve high speed and low hardware requirements for ECPM. It has been implemented over the binary field which is recommended by the National Institute of Standards and Technology (NIST). The proposed ECPM supports two Koblitz and random curves for the key sizes 233 and 163 bits. For group operations, a finite-field arithmetic operation, e.g. multiplication, is designed on a polynomial basis. The delay of a 233-bit point multiplication is only 3.05 and 3.56 μs, in a Xilinx Virtex-7 FPGA, for Koblitz and random curves, respectively, and 0.81 μs in an ASIC 65-nm technology, which are the fastest hardware implementation results reported in the literature to date. In addition, a 163-bit point multiplication is also implemented in FPGA and ASIC for fair comparison which takes around 0.33 and 0.46 μs, respectively. The area-time product of the proposed point multiplication is very low compared to similar designs. The performance (1Area×Time=1AT) and Area × Time × Energy (ATE) product of the proposed design are far better than the most significant studies found in the literature. PMID:28459831

Ecological association between HIV and concurrency point-prevalence in South Africa's ethnic groups.

PubMed

Kenyon, Chris

2013-11-01

HIV prevalence between different ethnic groups within South Africa exhibits considerable variation. Numerous authors believe that elevated sexual partner concurrency rates are important in the spread of HIV. Few studies have, however, investigated if differential concurrency rates could explain differential HIV spread within ethnic groups in South Africa. This ecological analysis, explores how much of the variation in HIV prevalence by ethnic group is explained by differential concurrency rates. Using a nationally representative survey (the South African National HIV Prevalence, HIV Incidence, Behaviour and Communication Survey, 2005) the HIV prevalence in each of eight major ethnic groups was calculated. Linear regression analysis was used to assess the association between an ethnic group's HIV prevalence and the point-prevalence of concurrency. Results showed that HIV prevalence rates varied considerably between South Africa's ethnic groups. This applied to both different racial groups and to different ethnic groups within the black group. The point-prevalence of concurrency by ethnic group was strongly associated with HIV prevalence (R(2) = 0.83; p = 0.001). Tackling the key drivers of high HIV transmission in this population may benefit from more emphasis on partner reduction interventions.

Nanothermodynamics of iron clusters: Small clusters, icosahedral and fcc-cuboctahedral structures

NASA Astrophysics Data System (ADS)

Angelié, C.; Soudan, J.-M.

2017-05-01

The study of the thermodynamics and structures of iron clusters has been carried on, focusing on small clusters and initial icosahedral and fcc-cuboctahedral structures. Two combined tools are used. First, energy intervals are explored by the Monte Carlo algorithm, called σ-mapping, detailed in the work of Soudan et al. [J. Chem. Phys. 135, 144109 (2011), Paper I]. In its flat histogram version, it provides the classical density of states, gp(Ep), in terms of the potential energy of the system. Second, the iron system is described by a potential which is called "corrected EAM" (cEAM), explained in the work of Basire et al. [J. Chem. Phys. 141, 104304 (2014), Paper II]. Small clusters from 3 to 12 atoms in their ground state have been compared first with published Density Functional Theory (DFT) calculations, giving a complete agreement of geometries. The series of 13, 55, 147, and 309 atom icosahedrons is shown to be the most stable form for the cEAM potential. However, the 147 atom cluster has a special behaviour, since decreasing the energy from the liquid zone leads to the irreversible trapping of the cluster in a reproducible amorphous state, 7.38 eV higher in energy than the icosahedron. This behaviour is not observed at the higher size of 309 atoms. The heat capacity of the 55, 147, and 309 atom clusters revealed a pronounced peak in the solid zone, related to a solid-solid transition, prior to the melting peak. The corresponding series of 13, 55, and 147 atom cuboctahedrons has been compared, underscoring the unstability towards the icosahedral structure. This unstability occurs clearly in several steps for the 147 atom cluster, with a sudden transformation at a transition state. This illustrates the concerted icosahedron-cuboctahedron transformation of Buckminster Fuller-Mackay, which is calculated for the cEAM potential. Two other clusters of initial fcc structures with 24 and 38 atoms have been studied, as well as a 302 atom cluster. Each one relaxes

75 FR 27119 - ViewPoint Financial Group, Inc., Plano, Texas; Approval of Conversion Application

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-13

... DEPARTMENT OF THE TREASURY Office of Thrift Supervision [AC-37: OTS No. H-47111] ViewPoint Financial Group, Inc., Plano, Texas; Approval of Conversion Application Notice is hereby given that on May 6, 2010, the Office of Thrift Supervision approved the application of ViewPoint MHC and ViewPoint Bank...

More on quantum groups from the quantization point of view

NASA Astrophysics Data System (ADS)

Jurčo, Branislav

1994-12-01

Star products on the classical double group of a simple Lie group and on corresponding symplectic groupoids are given so that the quantum double and the “quantized tangent bundle” are obtained in the deformation description. “Complex” quantum groups and bicovariant quantum Lie algebras are discussed from this point of view. Further we discuss the quantization of the Poisson structure on the symmetric algebra S(g) leading to the quantized enveloping algebra U h (g) as an example of biquantization in the sense of Turaev. Description of U h (g) in terms of the generators of the bicovariant differential calculus on F(G q ) is very convenient for this purpose. Finaly we interpret in the deformation framework some well known properties of compact quantum groups as simple consequences of corresponding properties of classical compact Lie groups. An analogue of the classical Kirillov's universal character formula is given for the unitary irreducble representation in the compact case.

Uncertainty relations, zero point energy and the linear canonical group

NASA Technical Reports Server (NTRS)

Sudarshan, E. C. G.

1993-01-01

The close relationship between the zero point energy, the uncertainty relations, coherent states, squeezed states, and correlated states for one mode is investigated. This group-theoretic perspective enables the parametrization and identification of their multimode generalization. In particular the generalized Schroedinger-Robertson uncertainty relations are analyzed. An elementary method of determining the canonical structure of the generalized correlated states is presented.

Structure-based engineering of an icosahedral virus for nanomedicine and nanotechnology.

PubMed

Steinmetz, N F; Lin, T; Lomonossoff, G P; Johnson, J E

2009-01-01

A quintessential tenet of nanotechnology is the self-assembly of nanometer-sized components into devices. Biological macromolecular systems such as viral particles were found to be suitable building blocks for nanotechnology for several reasons: viral capsids are extremely robust and can be produced in large quantities with ease, the particles self-assemble into monodisperse particles with a high degree of symmetry and polyvalency, they have the propensity to form arrays, and they offer programmability through genetic and chemical engineering. Here, we review the recent advances in engineering the icosahedral plant virus Cowpea mosaic virus (CPMV) for applications in nano-medicine and -technology. In the first part, we will discuss how the combined knowledge of the structure of CPMV at atomic resolution and the use of chimeric virus technology led to the generation of CPMV particles with short antigenic peptides for potential use as vaccine candidates. The second part focuses on the chemical addressability of CPMV. Strategies to chemically attach functional molecules at designed positions on the exterior surface of the viral particle are described. Biochemical conjugation methods led to the fabrication of electronically conducting CPMV particles and networks. In addition, functional proteins for targeted delivery to mammalian cells were successfully attached to CPMV. In the third part, we focus on the utilization of CPMV as a building block for the generation of 2D and 3D arrays. Overall, the potential applications of viral nanobuilding blocks are manifold and range from nanoelectronics to biomedical applications.

Dynamics of Transformation from Platinum Icosahedral Nanoparticles to Larger FCC Crystal at Millisecond Time Resolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Wenpei; Wu, Jianbo; Yoon, Aram

Atomic motion at grain boundaries is essential to microstructure development, growth and stability of catalysts and other nanostructured materials. However, boundary atomic motion is often too fast to observe in a conventional transmission electron microscope (TEM) and too slow for ultrafast electron microscopy. We report on the entire transformation process of strained Pt icosahedral nanoparticles (ICNPs) into larger FCC crystals, captured at 2.5 ms time resolution using a fast electron camera. Results show slow diffusive dislocation motion at nm/s inside ICNPs and fast surface transformation at μm/s. By characterizing nanoparticle strain, we show that the fast transformation is driven bymore » inhomogeneous surface stress. And interaction with pre-existing defects led to the slowdown of the transformation front inside the nanoparticles. Particle coalescence, assisted by oxygen-induced surface migration at T ≥ 300°C, also played a critical role. Thus by studying transformation in the Pt ICNPs at high time and spatial resolution, we obtain critical insights into the transformation mechanisms in strained Pt nanoparticles.« less

Virtual and Printed 3D Models for Teaching Crystal Symmetry and Point Groups

ERIC Educational Resources Information Center

Casas, Lluís; Estop, Euge`nia

2015-01-01

Both, virtual and printed 3D crystal models can help students and teachers deal with chemical education topics such as symmetry and point groups. In the present paper, two freely downloadable tools (interactive PDF files and a mobile app) are presented as examples of the application of 3D design to study point-symmetry. The use of 3D printing to…

Four-point functions and the permutation group S4

NASA Astrophysics Data System (ADS)

Eichmann, Gernot; Fischer, Christian S.; Heupel, Walter

2015-09-01

Four-point functions are at the heart of many interesting physical processes. A prime example is the light-by-light scattering amplitude, which plays an important role in the calculation of hadronic contributions to the anomalous magnetic moment of the muon. In the calculation of such quantities one faces the challenge of finding a suitable and well-behaved basis of tensor structures in coordinate and/or momentum space. Provided all (or many) of the external legs represent similar particle content, a powerful tool to construct and organize such bases is the permutation group S4. We introduce an efficient notation for dealing with the irreducible multiplets of S4, and we highlight the merits of this treatment by exemplifying four-point functions with gauge-boson legs such as the four-gluon vertex and the light-by-light scattering amplitude. The multiplet analysis is also useful for isolating the important kinematic regions and the dynamical singularity content of such amplitudes. Our analysis serves as a basis for future efficient calculations of these and similar objects.

Evaluation of new indigenous "point-of-care" ABO and Rh grouping device.

PubMed

Tiwari, Aseem Kumar; Setya, Divya; Aggarwal, Geet; Arora, Dinesh; Dara, Ravi C; Ratan, Ankita; Bhardwaj, Gunjan; Acharya, Devi Prasad

2018-01-01

Erycard 2.0 is a "point-of-care" device that is primarily being used for patient blood grouping before transfusion. Erycard 2.0 was compared with conventional slide technology for accuracy and time taken for ABO and Rh forward grouping result with column agglutination technology (CAT) being the gold standard. Erycard 2.0 as a device was also evaluated for its stability under different storage conditions and stability of result till 48 h. In addition, grouping of hemolyzed samples was also tested with Erycard 2.0. Ease of use of Erycard 2.0 was evaluated with a survey among paramedical staff. Erycard 2.0 demonstrated 100% concordance with CAT as compared with slide technique (98.9%). Mean time taken per test by Erycard 2.0 and slide technique was 5.13 min and 1.7 min, respectively. After pretesting storage under different temperature and humidity conditions, Erycard 2.0 did not show any deviation from the result. The result did not change even after 48 h of testing and storage under room temperature. 100% concordance was recorded between pre- and post-hemolyzed blood grouping. Ease of use survey revealed that Erycard 2.0 was more acceptable to paramedical staff for its simplicity, objectivity, and performance than conventional slide technique. Erycard 2.0 can be used as "point-of-care" device for blood donor screening for ABO and Rh blood group and can possibly replace conventional slide technique.

Gladwell and Group Communication: Using "The Tipping Point" as a Supplemental Text

ERIC Educational Resources Information Center

Browning, Blair W.

2011-01-01

This article describes an activity using Malcolm Gladwell's "The Tipping Point" as a supplemental text in an undergraduate group communication course. This book will help stimulate conversation and promote easy avenues for classroom discussion. In addition to weekly quizzes over each chapter to help facilitate rich classroom discussions, the…

Group vector space method for estimating enthalpy of vaporization of organic compounds at the normal boiling point.

PubMed

Wenying, Wei; Jinyu, Han; Wen, Xu

2004-01-01

The specific position of a group in the molecule has been considered, and a group vector space method for estimating enthalpy of vaporization at the normal boiling point of organic compounds has been developed. Expression for enthalpy of vaporization Delta(vap)H(T(b)) has been established and numerical values of relative group parameters obtained. The average percent deviation of estimation of Delta(vap)H(T(b)) is 1.16, which show that the present method demonstrates significant improvement in applicability to predict the enthalpy of vaporization at the normal boiling point, compared the conventional group methods.

Molecular Structure of a 9-MDa Icosahedral Pyruvate Dehydrogenase Subcomplex Containing the E2 and E3 Enzymes Using Cryoelectron Microscopy*

PubMed Central

Milne, Jacqueline L. S.; Wu, Xiongwu; Borgnia, Mario J.; Lengyel, Jeffrey S.; Brooks, Bernard R.; Shi, Dan; Perham, Richard N.; Subramaniam, Sriram

2006-01-01

The pyruvate dehydrogenase multienzyme complexes are among the largest multifunctional catalytic machines in cells, catalyzing the production of acetyl CoA from pyruvate. We have previously reported the molecular architecture of an 11-MDa subcomplex comprising the 60-mer icosahedral dihydrolipoyl acetyltransferase (E2) decorated with 60 copies of the heterotetrameric (α2β2) 153-kDa pyruvate decarboxylase (E1) from Bacillus stearothermophilus (Milne, J. L. S., Shi, D., Rosenthal, P. B., Sunshine, J. S., Domingo, G. J., Wu, X., Brooks, B. R., Perham, R. N., Henderson, R., and Subramaniam, S. (2002) EMBO J. 21, 5587–5598). An annular gap of ~90 Å separates the acetyltransferase catalytic domains of the E2 from an outer shell formed of E1 tetramers. Using cryoelectron microscopy, we present here a three-dimensional reconstruction of the E2 core decorated with 60 copies of the homodimeric 100-kDa dihydrolipoyl dehydrogenase (E3). The E2E3 complex has a similar annular gap of ~75 Å between the inner icosahedral assembly of acetyltransferase domains and the outer shell of E3 homodimers. Automated fitting of the E3 coordinates into the map suggests excellent correspondence between the density of the outer shell map and the positions of the two best fitting orientations of E3. As in the case of E1 in the E1E2 complex, the central 2-fold axis of the E3 homodimer is roughly oriented along the periphery of the shell, making the active sites of the enzyme accessible from the annular gap between the E2 core and the outer shell. The similarities in architecture of the E1E2 and E2E3 complexes indicate fundamental similarities in the mechanism of active site coupling involved in the two key stages requiring motion of the swinging lipoyl domain across the annular gap, namely the synthesis of acetyl CoA and regeneration of the dithiolane ring of the lipoyl domain. PMID:16308322

Evaluation of new indigenous “point-of-care” ABO and Rh grouping device

PubMed Central

Tiwari, Aseem Kumar; Setya, Divya; Aggarwal, Geet; Arora, Dinesh; Dara, Ravi C.; Ratan, Ankita; Bhardwaj, Gunjan; Acharya, Devi Prasad

2018-01-01

BACKGROUND: Erycard 2.0 is a “point-of-care” device that is primarily being used for patient blood grouping before transfusion. MATERIALS AND METHODS: Erycard 2.0 was compared with conventional slide technology for accuracy and time taken for ABO and Rh forward grouping result with column agglutination technology (CAT) being the gold standard. Erycard 2.0 as a device was also evaluated for its stability under different storage conditions and stability of result till 48 h. In addition, grouping of hemolyzed samples was also tested with Erycard 2.0. Ease of use of Erycard 2.0 was evaluated with a survey among paramedical staff. RESULTS: Erycard 2.0 demonstrated 100% concordance with CAT as compared with slide technique (98.9%). Mean time taken per test by Erycard 2.0 and slide technique was 5.13 min and 1.7 min, respectively. After pretesting storage under different temperature and humidity conditions, Erycard 2.0 did not show any deviation from the result. The result did not change even after 48 h of testing and storage under room temperature. 100% concordance was recorded between pre- and post-hemolyzed blood grouping. Ease of use survey revealed that Erycard 2.0 was more acceptable to paramedical staff for its simplicity, objectivity, and performance than conventional slide technique. CONCLUSION: Erycard 2.0 can be used as “point-of-care” device for blood donor screening for ABO and Rh blood group and can possibly replace conventional slide technique. PMID:29403211

Understanding the interface of six-shell cuboctahedral and icosahedral palladium clusters on reduced graphene oxide: experimental and theoretical study.

PubMed

Gracia-Espino, Eduardo; Hu, Guangzhi; Shchukarev, Andrey; Wågberg, Thomas

2014-05-07

Studies on noble-metal-decorated carbon nanostructures are reported almost on a daily basis, but detailed studies on the nanoscale interactions for well-defined systems are very rare. Here we report a study of reduced graphene oxide (rGOx) homogeneously decorated with palladium (Pd) nanoclusters with well-defined shape and size (2.3 ± 0.3 nm). The rGOx was modified with benzyl mercaptan (BnSH) to improve the interaction with Pd clusters, and N,N-dimethylformamide was used as solvent and capping agent during the decoration process. The resulting Pd nanoparticles anchored to the rGOx-surface exhibit high crystallinity and are fully consistent with six-shell cuboctahedral and icosahedral clusters containing ~600 Pd atoms, where 45% of these are located at the surface. According to X-ray photoelectron spectroscopy analysis, the Pd clusters exhibit an oxidized surface forming a PdO(x) shell. Given the well-defined experimental system, as verified by electron microscopy data and theoretical simulations, we performed ab initio simulations using 10 functionalized graphenes (with vacancies or pyridine, amine, hydroxyl, carboxyl, or epoxy groups) to understand the adsorption process of BnSH, their further role in the Pd cluster formation, and the electronic properties of the graphene-nanoparticle hybrid system. Both the experimental and theoretical results suggest that Pd clusters interact with functionalized graphene by a sulfur bridge while the remaining Pd surface is oxidized. Our study is of significant importance for all work related to anchoring of nanoparticles on nanocarbon-based supports, which are used in a variety of applications.

Scanning tuneeling microscopy studies of fivefold surfaces of icosahedral Al-Pd-Mn quasicrystals and of thin silver films on those surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Unal, Baris

2008-01-01

The present work in this dissertation mainly focuses on the clean fivefold surfaces of i-Al-Pd-Mn quasicrystals as well as the nucleation and growth of Ag films on these surfaces. In addition, Ag film growth on NiAl(110) has been explored in the frame of this dissertation. First, we have investigated the equilibration of a fivefold surface of icosahedral Al-Pd-Mn quasicrystal at 900-915 K and 925-950 K, using Omicron variable temperature scanning tunneling microscope (STM). Annealing at low temperatures resulted in many voids on some terraces while the others were almost void-free. After annealing at 925-950K, void-rich terraces became much rarer. Ourmore » STM images suggest that through growth and coalescence of the voids, a different termination becomes exposed on host terraces. All of these observations in our study indicate that even after the quasicrystalline terrace-step structure appears, it evolves with time and temperature. More specifically, based on the STM observations, we conclude that during the annealing a wide range of energetically similar layers nucleate as surface terminations, however, with increasing temperature (and time) this distribution gets narrower via elimination of the metastable void-rich terraces. Next, we have examined the bulk structural models of icosahedral Al-Pd-Mn quasicrystal in terms of the densities, compositions and interplanar spacings for the fivefold planes that might represent physical surface terminations. In our analyses, we mainly have focused on four deterministic models which have no partial or mixed occupancy but we have made some comparisons with an undeterministic model. We have compared the models with each other and also with the available experimental data including STM, LEED-IV, XPD and LEIS. In all deterministic models, there are two different families of layers (a pair of planes), and the nondeterministic model contains similar group of planes. These two families differ in terms of the chemical

Renormalization group equations and the Lifshitz point in noncommutative Landau-Ginsburg theory

NASA Astrophysics Data System (ADS)

Chen, Guang-Hong; Wu, Yong-Shi

2002-02-01

A one-loop renormalization group (RG) analysis is performed for noncommutative Landau-Ginsburg theory in an arbitrary dimension. We adopt a modern version of the Wilsonian RG approach, in which a shell integration in momentum space bypasses the potential IR singularities due to UV-IR mixing. The momentum-dependent trigonometric factors in interaction vertices, characteristic of noncommutative geometry, are marginal under RG transformations, and their marginality is preserved at one loop. A negative Θ-dependent anomalous dimension is discovered as a novel effect of the UV-IR mixing. We also found a noncommutative Wilson-Fisher (NCWF) fixed point in less than four dimensions. At large noncommutativity, a momentum space instability is induced by quantum fluctuations, and a consequential first-order phase transition is identified together with a Lifshitz point in the phase diagram. In the vicinity of the Lifshitz point, we introduce two critical exponents νm and βk, whose values are determined to be 1/4 and 1/2, respectively, at mean-field level.

Current algebras, measures quasi-invariant under diffeomorphism groups, and infinite quantum systems with accumulation points

NASA Astrophysics Data System (ADS)

Sakuraba, Takao

The approach to quantum physics via current algebra and unitary representations of the diffeomorphism group is established. This thesis studies possible infinite Bose gas systems using this approach. Systems of locally finite configurations and systems of configurations with accumulation points are considered, with the main emphasis on the latter. In Chapter 2, canonical quantization, quantization via current algebra and unitary representations of the diffeomorphism group are reviewed. In Chapter 3, a new definition of the space of configurations is proposed and an axiom for general configuration spaces is abstracted. Various subsets of the configuration space, including those specifying the number of points in a Borel set and those specifying the number of accumulation points in a Borel set are proved to be measurable using this axiom. In Chapter 4, known results on the space of locally finite configurations and Poisson measure are reviewed in the light of the approach developed in Chapter 3, including the approach to current algebra in the Poisson space by Albeverio, Kondratiev, and Rockner. Goldin and Moschella considered unitary representations of the group of diffeomorphisms of the line based on self-similar random processes, which may describe infinite quantum gas systems with clusters. In Chapter 5, the Goldin-Moschella theory is developed further. Their construction of measures quasi-invariant under diffeomorphisms is reviewed, and a rigorous proof of their conjectures is given. It is proved that their measures with distinct correlation parameters are mutually singular. A quasi-invariant measure constructed by Ismagilov on the space of configurations with accumulation points on the circle is proved to be singular with respect to the Goldin-Moschella measures. Finally a generalization of the Goldin-Moschella measures to the higher-dimensional case is studied, where the notion of covariance matrix and the notion of condition number play important roles. A

Testing the renormalisation group theory of cooperative transitions at the lambda point of helium

NASA Technical Reports Server (NTRS)

Lipa, J. A.; Li, Q.; Chui, T. C. P.; Marek, D.

1988-01-01

The status of high resolution tests of the renormalization group theory of cooperative phase transitions performed near the lambda point of helium is described. The prospects for performing improved tests in space are discussed.

Group- and Individual-Level Responsiveness of the 3-Point Berg Balance Scale and 3-Point Postural Assessment Scale for Stroke Patients.

PubMed

Huang, Yi-Jing; Lin, Gong-Hong; Lee, Shih-Chieh; Chen, Yi-Miau; Huang, Sheau-Ling; Hsieh, Ching-Lin

2018-03-01

To examine both group- and individual-level responsiveness of the 3-point Berg Balance Scale (BBS-3P) and 3-point Postural Assessment Scale for Stroke Patients (PASS-3P) in patients with stroke, and to compare the responsiveness of both 3-point measures versus their original measures (Berg Balance Scale [BBS] and Postural Assessment Scale for Stroke Patients [PASS]) and their short forms (short-form Berg Balance Scale [SFBBS] and short-form Postural Assessment Scale for Stroke Patients [SFPASS]) and between the BBS-3P and PASS-3P. Data were retrieved from a previous study wherein 212 patients were assessed at 14 and 30 days after stroke with the BBS and PASS. Medical center. Patients (N=212) with first onset of stroke within 14 days before hospitalization. Not applicable. Group-level responsiveness was examined by the standardized response mean (SRM), and individual-level responsiveness was examined by the proportion of patients whose change scores exceeded the minimal detectable change of each measure. The responsiveness was compared using the bootstrap approach. The BBS-3P and PASS-3P had good group-level (SRM, .60 and SRM, .56, respectively) and individual-level (48.1% and 44.8% of the patients with significant improvement, respectively) responsiveness. Bootstrap analyses showed that the BBS-3P generally had superior responsiveness to the BBS and SFBBS, and the PASS-3P had similar responsiveness to the PASS and SFPASS. The BBS-3P and PASS-3P were equally responsive to both group and individual change. The responsiveness of the BBS-3P and PASS-3P was comparable or superior to those of the original and short-form measures. We recommend the BBS-3P and PASS-3P as responsive outcome measures of balance for individuals with stroke. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Improving the Grade Point Average of Our At-Risk Students: A Collaborative Group Action Research Approach.

ERIC Educational Resources Information Center

Saurino, Dan R.; Hinson, Kenneth; Bouma, Amy

This paper focuses on the use of a group action research approach to help student teachers develop strategies to improve the grade point average of at-risk students. Teaching interventions such as group work and group and individual tutoring were compared to teaching strategies already used in the field. Results indicated an improvement in the…

High-resolution electron microscopy observation of a new crystalline approximant W' of Mg-Zn-Y icosahedral quasicrystal

PubMed

Luo; Hashimoto

2000-10-01

A new ordered structure W' with a lattice parameter (a = 2.05 nm) about three times as large as that of the fundamental face-centered cubic W phase (a = 0.6848 nm) has been found in the Mg-Zn-Y system by means of transmission electron microscopy. The W' and W phases have the cube-to-cube orientation relationship. Moreover, the strong electron diffraction spots of the W' phase showed pseudoicosahedral symmetry, implying that it is a crystalline approximant of the Mg-Zn-Y icosahedral quasicrystal. In the high-resolution electron microscopic images of the W' phase, Penrose tiles of pentagons and boats with an edge length of a(p) = 0.481 nm can be identified. A binary tile of crown subunit has also been deduced from such a tiling. Translation domains of the W' phase have also been observed and the translation vectors at the domain boundary are: a(p), tau x a(p) and (1 + tau) x a(p), respectively, where (1 + tau) x a(p) equals to the edge length a(r) of the big obtuse rhombus of the W' phase and tau = (1 + square root of 5)/2, is the golden ratio.

The icosahedral RNA virus as a grotto: organizing the genome into stalagmites and stalactites.

PubMed

Harvey, Stephen C; Zeng, Yingying; Heitsch, Christine E

2013-03-01

There are two important problems in the assembly of small, icosahedral RNA viruses. First, how does the capsid protein select the viral RNA for packaging, when there are so many other candidate RNA molecules available? Second, what is the mechanism of assembly? With regard to the first question, there are a number of cases where a particular RNA sequence or structure--often one or more stem-loops--either promotes assembly or is required for assembly, but there are others where specific packaging signals are apparently not required. With regard to the assembly pathway, in those cases where stem-loops are involved, the first step is generally believed to be binding of the capsid proteins to these "fingers" of the RNA secondary structure. In the mature virus, the core of the RNA would then occupy the center of the viral particle, and the stem-loops would reach outward, towards the capsid, like stalagmites reaching up from the floor of a grotto towards the ceiling. Those viruses whose assembly does not depend on protein binding to stem-loops could have a different structure, with the core of the RNA lying just under the capsid, and the fingers reaching down into the interior of the virus, like stalactites. We review the literature on these alternative structures, focusing on RNA selectivity and the assembly mechanism, and we propose experiments aimed at determining, in a given virus, which of the two structures actually occurs.

Theoretical and Numerical Modeling of faceted Ionic crystalline vesicles

NASA Astrophysics Data System (ADS)

Olvera de La Cruz, Monica

2007-03-01

Icosahedral shape is found in several natural structures including large viruses, large fullerenes and cationic-anionic vesicles. Faceting into icosahedral shape can occur in large crystalline membranes via elasticity theory. Icosahedral symmetry is found in small systems of particles with short-range interactions on a sphere. Dr G. Vernizzi and I show a novel electrostatic-driven mechanism of ionic crystalline shells faceting into icosahedral shapes even for systems with a small number of particles. Icosahedral shape is possible in cationic and anionic molecules adsorbed onto spherical interfaces, such as emulsions or other immiscible liquid droplets because the large concentration of charges at the interface can lead to ionic crystals on the curved interface. Such self-organized ionic structures favors the formation of flat surfaces. We find that these ionic crystalline shells can have lower energy when faceted into icosahedra along particular directions. Indeed, the ``ionic'' buckling is driven by preferred bending directions of the planar ionic structure, along which is more likely for the icosahedral shape to develop an edge. Since only certain orientations are allowed, rotational symmetry is broken. One can hope to exploit this mechanism to generate functional materials where, for instance, proteins with specific charge groups can orient at specific directions along an icosahedral cationic-anionic vesicle.

Structure of the orthorhombic form of Mn(2)Al(7), Fe(2)Al(7), and (Mn(0.7)Fe(0.3))(2)Al(7) that by twinning produces grains with decagonal point-group symmetry.

PubMed

Pauling, L

1988-04-01

Analysis of electron diffraction photographs of grains of Mn(2)Al(7), Fe(2)Al(7), and (Mn(0.7)Fe(0.3))(2)Al(7) leads to the conclusion that they are 5-fold twins of a 1664-atom orthorhombic crystal with a = 32.86 A, b = 31.23 A, and c = 24.80 A and with 16 icosahedral clusters of 104 atoms in positions shifted by small amounts from those of the cubic beta-tungsten structure.

Teaching Molecular Symmetry of Dihedral Point Groups by Drawing Useful 2D Projections

ERIC Educational Resources Information Center

Chen, Lan; Sun, Hongwei; Lai, Chengming

2015-01-01

There are two main difficulties in studying molecular symmetry of dihedral point groups. One is locating the C[subscript 2] axes perpendicular to the C[subscript n] axis, while the other is finding the s[subscript]d planes which pass through the C[subscript n] axis and bisect the angles formed by adjacent C[subscript 2] axes. In this paper, a…

Structure of the orthorhombic form of Mn2Al7, Fe2Al7, and (Mn0.7Fe0.3)2Al7 that by twinning produces grains with decagonal point-group symmetry

PubMed Central

Pauling, Linus

1988-01-01

Analysis of electron diffraction photographs of grains of Mn2Al7, Fe2Al7, and (Mn0.7Fe0.3)2Al7 leads to the conclusion that they are 5-fold twins of a 1664-atom orthorhombic crystal with a = 32.86 Å, b = 31.23 Å, and c = 24.80 Å and with 16 icosahedral clusters of 104 atoms in positions shifted by small amounts from those of the cubic β-tungsten structure. PMID:16593921

Interpenetration of a 3D Icosahedral M@Ni12 (M=Al, Ga) Framework with Porphyrin-Reminiscent Boron Layers in MNi9 B8.

PubMed

Zheng, Qiang; Wagner, Frank R; Ormeci, Alim; Prots, Yurii; Burkhardt, Ulrich; Schmidt, Marcus; Schnelle, Walter; Grin, Yuri; Leithe-Jasper, Andreas

2015-11-09

Two ternary borides MNi9 B8 (M=Al, Ga) were synthesized by thermal treatment of mixtures of the elements. Single-crystal X-ray diffraction data reveal AlNi9 B8 and GaNi9 B8 crystallizing in a new type of structure within the space group Cmcm and the lattice parameters a=7.0896(3) Å, b=8.1181(3) Å, c=10.6497(4) Å and a=7.0897(5) Å, b=8.1579(4) Å, c=10.6648(7) Å, respectively. The boron atoms build up two-dimensional layers, which consist of puckered [B16 ] rings with two tailing B atoms, whereas the M atoms reside in distorted vertices-condensed [Ni12 ] icosahedra, which form a three-dimensional framework interpenetrated by boron porphyrin-reminiscent layers. An unusual local arrangement resembling a giant metallo-porphyrin entity is formed by the [B16 ] rings, which, due to their large annular size of approximately 8 Å, chelate four of the twelve icosahedral Ni atoms. An analysis of the chemical bonding by means of the electron localizability approach reveals strong covalent B-B interactions and weak Ni-Ni interactions. Multi-center dative B-Ni interaction occurs between the Al-Ni framework and the boron layers. In agreement with the chemical bonding analysis and band structure calculations, AlNi9 B8 is a Pauli-paramagnetic metal. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Providing full point-to-point communications among compute nodes of an operational group in a global combining network of a parallel computer

DOEpatents

Archer, Charles J; Faraj, Ahmad A; Inglett, Todd A; Ratterman, Joseph D

2013-04-16

Methods, apparatus, and products are disclosed for providing full point-to-point communications among compute nodes of an operational group in a global combining network of a parallel computer, each compute node connected to each adjacent compute node in the global combining network through a link, that include: receiving a network packet in a compute node, the network packet specifying a destination compute node; selecting, in dependence upon the destination compute node, at least one of the links for the compute node along which to forward the network packet toward the destination compute node; and forwarding the network packet along the selected link to the adjacent compute node connected to the compute node through the selected link.

Point of care testing of phospholipase A2 group IIA for serological diagnosis of rheumatoid arthritis

NASA Astrophysics Data System (ADS)

Liu, Nathan J.; Chapman, Robert; Lin, Yiyang; Mmesi, Jonas; Bentham, Andrew; Tyreman, Matthew; Abraham, Sonya; Stevens, Molly M.

2016-02-01

Secretory phospholipase A2 group IIA (sPLA2-IIA) was examined as a point of care marker for determining disease activity in rheumatoid (RA) and psoriatic (PsA) arthritis. Serum concentration and activity of sPLA2-IIA were measured using in-house antibodies and a novel point of care lateral flow device assay in patients diagnosed with varying severities of RA (n = 30) and PsA (n = 25) and found to correlate strongly with C-reactive protein (CRP). Levels of all markers were elevated in patients with active RA over those with inactive RA as well as both active and inactive PsA, indicating that sPLA2-IIA can be used as an analogue to CRP for RA diagnosis at point of care.Secretory phospholipase A2 group IIA (sPLA2-IIA) was examined as a point of care marker for determining disease activity in rheumatoid (RA) and psoriatic (PsA) arthritis. Serum concentration and activity of sPLA2-IIA were measured using in-house antibodies and a novel point of care lateral flow device assay in patients diagnosed with varying severities of RA (n = 30) and PsA (n = 25) and found to correlate strongly with C-reactive protein (CRP). Levels of all markers were elevated in patients with active RA over those with inactive RA as well as both active and inactive PsA, indicating that sPLA2-IIA can be used as an analogue to CRP for RA diagnosis at point of care. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr08423g

Providing full point-to-point communications among compute nodes of an operational group in a global combining network of a parallel computer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Archer, Charles J.; Faraj, Daniel A.; Inglett, Todd A.

Methods, apparatus, and products are disclosed for providing full point-to-point communications among compute nodes of an operational group in a global combining network of a parallel computer, each compute node connected to each adjacent compute node in the global combining network through a link, that include: receiving a network packet in a compute node, the network packet specifying a destination compute node; selecting, in dependence upon the destination compute node, at least one of the links for the compute node along which to forward the network packet toward the destination compute node; and forwarding the network packet along the selectedmore » link to the adjacent compute node connected to the compute node through the selected link.« less

Exact renormalization group equation for the Lifshitz critical point

NASA Astrophysics Data System (ADS)

Bervillier, C.

2004-10-01

An exact renormalization equation (ERGE) accounting for an anisotropic scaling is derived. The critical and tricritical Lifshitz points are then studied at leading order of the derivative expansion which is shown to involve two differential equations. The resulting estimates of the Lifshitz critical exponents compare well with the O(ε) calculations. In the case of the Lifshitz tricritical point, it is shown that a marginally relevant coupling defies the perturbative approach since it actually makes the fixed point referred to in the previous perturbative calculations O(ε) finally unstable.

Improvement of aerosol optical properties modeling over Eastern Asia with MODIS AOD assimilation in a global non-hydrostatic icosahedral aerosol transport model.

PubMed

Dai, Tie; Schutgens, Nick A J; Goto, Daisuke; Shi, Guangyu; Nakajima, Teruyuki

2014-12-01

A new global aerosol assimilation system adopting a more complex icosahedral grid configuration is developed. Sensitivity tests for the assimilation system are performed utilizing satellite retrieved aerosol optical depth (AOD) from the Moderate Resolution Imaging Spectroradiometer (MODIS), and the results over Eastern Asia are analyzed. The assimilated results are validated through independent Aerosol Robotic Network (AERONET) observations. Our results reveal that the ensemble and local patch sizes have little effect on the assimilation performance, whereas the ensemble perturbation method has the largest effect. Assimilation leads to significantly positive effect on the simulated AOD field, improving agreement with all of the 12 AERONET sites over the Eastern Asia based on both the correlation coefficient and the root mean square difference (assimilation efficiency). Meanwhile, better agreement of the Ångström Exponent (AE) field is achieved for 8 of the 12 sites due to the assimilation of AOD only. Copyright © 2014 Elsevier Ltd. All rights reserved.

- and Graph-Based Point Cloud Segmentation of 3d Scenes Using Perceptual Grouping Laws

NASA Astrophysics Data System (ADS)

Xu, Y.; Hoegner, L.; Tuttas, S.; Stilla, U.

2017-05-01

Segmentation is the fundamental step for recognizing and extracting objects from point clouds of 3D scene. In this paper, we present a strategy for point cloud segmentation using voxel structure and graph-based clustering with perceptual grouping laws, which allows a learning-free and completely automatic but parametric solution for segmenting 3D point cloud. To speak precisely, two segmentation methods utilizing voxel and supervoxel structures are reported and tested. The voxel-based data structure can increase efficiency and robustness of the segmentation process, suppressing the negative effect of noise, outliers, and uneven points densities. The clustering of voxels and supervoxel is carried out using graph theory on the basis of the local contextual information, which commonly conducted utilizing merely pairwise information in conventional clustering algorithms. By the use of perceptual laws, our method conducts the segmentation in a pure geometric way avoiding the use of RGB color and intensity information, so that it can be applied to more general applications. Experiments using different datasets have demonstrated that our proposed methods can achieve good results, especially for complex scenes and nonplanar surfaces of objects. Quantitative comparisons between our methods and other representative segmentation methods also confirms the effectiveness and efficiency of our proposals.

Atomic model of anti-phase boundaries in a face-centred icosahedral Zn Mg Dy quasicrystal

NASA Astrophysics Data System (ADS)

Wang, Jianbo; Yang, Wenge; Wang, Renhui

2003-03-01

An atomic model in the physical space for an anti-phase boundary (APB) in the ordered face-centred icosahedral Zn-Mg-Dy quasicrystal phase is presented, based on a six-dimensional model suggested by Ishimasa and Shimizu (2000 Mater. Sci. Eng. A 294-296 232, Ishimasa 2001 private communication). The physical space atomic positions of the defected structure were used for the calculation of the corresponding exit-plane wavefunction and high-resolution transmission electron microscopy images. The analysis of the defect by inverse Fourier transformation reveals that when superstructure reflection spots are used for back-transformation, then at the APB, bright lattice fringes are found to turn into dark ones, and vice versa. When fundamental reflections are used, the APB is not visible. This phenomenon is the same as the corresponding experimental study recently published by Heggen et al(2001a Phys. Rev. B 64 014202). Based on this atomic model it is found that the APB perpendicular to a fivefold axis A5 (APB-A5) is a non-conservative boundary, while the APB perpendicular to a pseudo-twofold axis A2P (APB-A2P) is a conservative one. This fact is consistent with the experimental observation (Heggen et al2002 J. Alloys Compounds 342 330) that the frequency of occurrence of APB-A5 is 90% in the heat-treated samples compared with that in the deformed samples (45%), while the frequency of occurrence of APB-A2P is 34% in the deformed samples compared with that in the heat-treated samples.

Sample size and classification error for Bayesian change-point models with unlabelled sub-groups and incomplete follow-up.

PubMed

White, Simon R; Muniz-Terrera, Graciela; Matthews, Fiona E

2018-05-01

Many medical (and ecological) processes involve the change of shape, whereby one trajectory changes into another trajectory at a specific time point. There has been little investigation into the study design needed to investigate these models. We consider the class of fixed effect change-point models with an underlying shape comprised two joined linear segments, also known as broken-stick models. We extend this model to include two sub-groups with different trajectories at the change-point, a change and no change class, and also include a missingness model to account for individuals with incomplete follow-up. Through a simulation study, we consider the relationship of sample size to the estimates of the underlying shape, the existence of a change-point, and the classification-error of sub-group labels. We use a Bayesian framework to account for the missing labels, and the analysis of each simulation is performed using standard Markov chain Monte Carlo techniques. Our simulation study is inspired by cognitive decline as measured by the Mini-Mental State Examination, where our extended model is appropriate due to the commonly observed mixture of individuals within studies who do or do not exhibit accelerated decline. We find that even for studies of modest size ( n = 500, with 50 individuals observed past the change-point) in the fixed effect setting, a change-point can be detected and reliably estimated across a range of observation-errors.

Highly specific salt bridges govern bacteriophage P22 icosahedral capsid assembly: identification of the site in coat protein responsible for interaction with scaffolding protein.

PubMed

Cortines, Juliana R; Motwani, Tina; Vyas, Aashay A; Teschke, Carolyn M

2014-05-01

Icosahedral virus assembly requires a series of concerted and highly specific protein-protein interactions to produce a proper capsid. In bacteriophage P22, only coat protein (gp5) and scaffolding protein (gp8) are needed to assemble a procapsid-like particle, both in vivo and in vitro. In scaffolding protein's coat binding domain, residue R293 is required for procapsid assembly, while residue K296 is important but not essential. Here, we investigate the interaction of scaffolding protein with acidic residues in the N-arm of coat protein, since this interaction has been shown to be electrostatic. Through site-directed mutagenesis of genes 5 and 8, we show that changing coat protein N-arm residue 14 from aspartic acid to alanine causes a lethal phenotype. Coat protein residue D14 is shown by cross-linking to interact with scaffolding protein residue R293 and, thus, is intimately involved in proper procapsid assembly. To a lesser extent, coat protein N-arm residue E18 is also implicated in the interaction with scaffolding protein and is involved in capsid size determination, since a cysteine mutation at this site generated petite capsids. The final acidic residue in the N-arm that was tested, E15, is shown to only weakly interact with scaffolding protein's coat binding domain. This work supports growing evidence that surface charge density may be the driving force of virus capsid protein interactions. Bacteriophage P22 infects Salmonella enterica serovar Typhimurium and is a model for icosahedral viral capsid assembly. In this system, coat protein interacts with an internal scaffolding protein, triggering the assembly of an intermediate called a procapsid. Previously, we determined that there is a single amino acid in scaffolding protein required for P22 procapsid assembly, although others modulate affinity. Here, we identify partners in coat protein. We show experimentally that relatively weak interactions between coat and scaffolding proteins are capable of driving

Atomic Scale Investigation of Structural Properties and Glass Forming Ability of Ti100-x Al x Metallic Glasses

NASA Astrophysics Data System (ADS)

Tahiri, M.; Hasnaoui, A.; Sbiaai, K.

2018-03-01

In this work, we employed molecular dynamics (MD) simulations to study Ti-Al metallic glasses (MGs) using the embedded atom method (EAM) potential to model the atomic interaction with different compositions. The results showed evidence of the metallic glass formation induced by the split occurring in the second peak of the radial distribution function (RDF) curves implying both Ti and Al atoms. The common neighbor analysis (CNA) method confirmed the presence of the icosahedral clusters with a maximum amount observed for an alloy with 75 pct of Al. Analysis of coordination numbers (CNs) indicated that the total CNs are nearly unchanged in these systems. Finally, Voronoi tessellation analyses (VTA) showed a higher value of the number of icosahedral units at Ti25Al75 composition. This specific composition represents a nearby peritectic point localized at a low melting point in the Ti-Al binary phase diagram. The glass forming ability (GFA) becomes important when the fraction of Al increases by forming and connecting "icosahedral-like" clusters (12-coordinated <0, 0, 12, 0> and 13-coordinated <0, 1, 10, 2>) and by playing a main role in the structure stability of the Ti-Al MGs.

Atomic Scale Investigation of Structural Properties and Glass Forming Ability of Ti100- x Al x Metallic Glasses

NASA Astrophysics Data System (ADS)

Tahiri, M.; Hasnaoui, A.; Sbiaai, K.

2018-06-01

In this work, we employed molecular dynamics (MD) simulations to study Ti-Al metallic glasses (MGs) using the embedded atom method (EAM) potential to model the atomic interaction with different compositions. The results showed evidence of the metallic glass formation induced by the split occurring in the second peak of the radial distribution function (RDF) curves implying both Ti and Al atoms. The common neighbor analysis (CNA) method confirmed the presence of the icosahedral clusters with a maximum amount observed for an alloy with 75 pct of Al. Analysis of coordination numbers (CNs) indicated that the total CNs are nearly unchanged in these systems. Finally, Voronoi tessellation analyses (VTA) showed a higher value of the number of icosahedral units at Ti25Al75 composition. This specific composition represents a nearby peritectic point localized at a low melting point in the Ti-Al binary phase diagram. The glass forming ability (GFA) becomes important when the fraction of Al increases by forming and connecting "icosahedral-like" clusters (12-coordinated <0, 0, 12, 0> and 13-coordinated <0, 1, 10, 2>) and by playing a main role in the structure stability of the Ti-Al MGs.

An Icosahedral Quasicrystal and Its 1/0 Crystalline Approximant in the Ca–Au–Al System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pham, Joyce; Kreyssig, Andreas; Goldman, Alan I.

2016-10-17

A new icosahedral quasicrystalline phase, CaAu4.5–xAl1.5+x [0.11 ≤ x ≤ 0.40(6); CaAu4.4Al1.6, aQC = 5.383(4) Å, and Pm35], and its lowest-order 1/0 cubic crystalline approximant phase, CaAu3+xAl1–x [0 ≤ x ≤ 0.31(1); a = 9.0766(5)–9.1261(8) Å, Pa3(No. 205), and Pearson symbol cP40], have been discovered in the Ca-poor region of the Ca–Au–Al system. In the crystalline approximant, eight [Au3–xAl1+x] tetrahedra fill the unit cell, and each tetrahedron is surrounded by four Ca atoms, thus forming a three-dimensional network of {Ca4/4[Au3–xAl1+x]} tetrahedral stars. A computational study of Au and Al site preferences concurs with the experimental results, which indicate a preferencemore » for near-neighbor Au–Al interactions over Au–Au and Al–Al interactions. Analysis of the electronic density of states and the associated crystal orbital Hamilton population curves was used to rationalize the descriptions of CaAu4.5–xAl1.5+x [0.11 ≤ x ≤ 0.46(6)] and CaAu3+xAl1–x [0 ≤ x ≤ 0.31(1)] as polar intermetallic species, whereby Ca atoms engage in polar covalent bonding with the electronegative, electron-deficient [Au3–xAl1+x] tetrahedral clusters and the observed phase width of the crystalline approximant.« less

Assembly/disassembly of a complex icosahedral virus to incorporate heterologous nucleic acids

NASA Astrophysics Data System (ADS)

Pascual, Elena; Mata, Carlos P.; Carrascosa, José L.; Castón, José R.

2017-12-01

Hollow protein containers are widespread in nature, and include virus capsids as well as eukaryotic and bacterial complexes. Protein cages are studied extensively for applications in nanotechnology, nanomedicine and materials science. Their inner and outer surfaces can be modified chemically or genetically, and the internal cavity can be used to template, store and/or arrange molecular cargos. Virus capsids and virus-like particles (VLP, noninfectious particles) provide versatile platforms for nanoscale bioengineering. Study of capsid protein self-assembly into monodispersed particles, and of VLP structure and biophysics is necessary not only to understand natural processes, but also to infer how these platforms can be redesigned to furnish novel functional VLP. Here we address the assembly dynamics of infectious bursal disease virus (IBDV), a complex icosahedral virus. IBDV has a ~70 nm-diameter T  =  13 capsid with VP2 trimers as the only structural subunits. During capsid assembly, VP2 is synthesized as a precursor (pVP2) whose C terminus is cleaved. The pVP2 C terminus has an amphipathic helix that controls VP2 polymorphism. In the absence of the VP3 scaffolding protein, necessary for control of assembly, 466/456-residue pVP2 intermediates bearing this helix assemble into VLP only when expressed with an N-terminal His6 tag (the HT-VP2-466 protein). HT-VP2-466 capsids are optimal for genetic insertion of proteins (cargo space ~78 000 nm3). We established an in vitro assembly/disassembly system of HT-VP2-466-based VLP for heterologous nucleic acid packaging and/or encapsulation of drugs and other molecules. HT-VP2-466 (empty) capsids were disassembled and reassembled by dialysis against low-salt/basic pH and high-salt/acid pH buffers, respectively, thus illustrating the reversibility in vitro of IBDV capsid assembly. HT-VP2-466 VLP also packed heterologous DNA by non-specific confinement during assembly. These and previous results establish the bases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cameron, Maria K., E-mail: cameron@math.umd.edu

We develop computational tools for spectral analysis of stochastic networks representing energy landscapes of atomic and molecular clusters. Physical meaning and some properties of eigenvalues, left and right eigenvectors, and eigencurrents are discussed. We propose an approach to compute a collection of eigenpairs and corresponding eigencurrents describing the most important relaxation processes taking place in the system on its way to the equilibrium. It is suitable for large and complex stochastic networks where pairwise transition rates, given by the Arrhenius law, vary by orders of magnitude. The proposed methodology is applied to the network representing the Lennard-Jones-38 cluster created bymore » Wales's group. Its energy landscape has a double funnel structure with a deep and narrow face-centered cubic funnel and a shallower and wider icosahedral funnel. However, the complete spectrum of the generator matrix of the Lennard-Jones-38 network has no appreciable spectral gap separating the eigenvalue corresponding to the escape from the icosahedral funnel. We provide a detailed description of the escape process from the icosahedral funnel using the eigencurrent and demonstrate a superexponential growth of the corresponding eigenvalue. The proposed spectral approach is compared to the methodology of the Transition Path Theory. Finally, we discuss whether the Lennard-Jones-38 cluster is metastable from the points of view of a mathematician and a chemical physicist, and make a connection with experimental works.« less

A mimetic, semi-implicit, forward-in-time, finite volume shallow water model: comparison of hexagonal-icosahedral and cubed sphere grids

NASA Astrophysics Data System (ADS)

Thuburn, J.; Cotter, C. J.; Dubos, T.

2013-12-01

A new algorithm is presented for the solution of the shallow water equations on quasi-uniform spherical grids. It combines a mimetic finite volume spatial discretization with a Crank-Nicolson time discretization of fast waves and an accurate and conservative forward-in-time advection scheme for mass and potential vorticity (PV). The algorithm is implemented and tested on two families of grids: hexagonal-icosahedral Voronoi grids, and modified equiangular cubed-sphere grids. Results of a variety of tests are presented, including convergence of the discrete scalar Laplacian and Coriolis operators, advection, solid body rotation, flow over an isolated mountain, and a barotropically unstable jet. The results confirm a number of desirable properties for which the scheme was designed: exact mass conservation, very good available energy and potential enstrophy conservation, consistent mass, PV and tracer transport, and good preservation of balance including vanishing ∇ × ∇, steady geostrophic modes, and accurate PV advection. The scheme is stable for large wave Courant numbers and advective Courant numbers up to about 1. In the most idealized tests the overall accuracy of the scheme appears to be limited by the accuracy of the Coriolis and other mimetic spatial operators, particularly on the cubed sphere grid. On the hexagonal grid there is no evidence for damaging effects of computational Rossby modes, despite attempts to force them explicitly.

A mimetic, semi-implicit, forward-in-time, finite volume shallow water model: comparison of hexagonal-icosahedral and cubed-sphere grids

NASA Astrophysics Data System (ADS)

Thuburn, J.; Cotter, C. J.; Dubos, T.

2014-05-01

A new algorithm is presented for the solution of the shallow water equations on quasi-uniform spherical grids. It combines a mimetic finite volume spatial discretization with a Crank-Nicolson time discretization of fast waves and an accurate and conservative forward-in-time advection scheme for mass and potential vorticity (PV). The algorithm is implemented and tested on two families of grids: hexagonal-icosahedral Voronoi grids, and modified equiangular cubed-sphere grids. Results of a variety of tests are presented, including convergence of the discrete scalar Laplacian and Coriolis operators, advection, solid body rotation, flow over an isolated mountain, and a barotropically unstable jet. The results confirm a number of desirable properties for which the scheme was designed: exact mass conservation, very good available energy and potential enstrophy conservation, consistent mass, PV and tracer transport, and good preservation of balance including vanishing ∇ × ∇, steady geostrophic modes, and accurate PV advection. The scheme is stable for large wave Courant numbers and advective Courant numbers up to about 1. In the most idealized tests the overall accuracy of the scheme appears to be limited by the accuracy of the Coriolis and other mimetic spatial operators, particularly on the cubed-sphere grid. On the hexagonal grid there is no evidence for damaging effects of computational Rossby modes, despite attempts to force them explicitly.

Melting phenomena: effect of composition for 55-atom Ag-Pd bimetallic clusters.

PubMed

Cheng, Daojian; Wang, Wenchuan; Huang, Shiping

2008-05-14

Understanding the composition effect on the melting processes of bimetallic clusters is important for their applications. Here, we report the relationship between the melting point and the metal composition for the 55-atom icosahedral Ag-Pd bimetallic clusters by canonical Monte Carlo simulations, using the second-moment approximation of the tight-binding potentials (TB-SMA) for the metal-metal interactions. Abnormal melting phenomena for the systems of interest are found. Our simulation results reveal that the dependence of the melting point on the composition is not a monotonic change, but experiences three different stages. The melting temperatures of the Ag-Pd bimetallic clusters increase monotonically with the concentration of the Ag atoms first. Then, they reach a plateau presenting almost a constant value. Finally, they decrease sharply at a specific composition. The main reason for this change can be explained in terms of the relative stability of the Ag-Pd bimetallic clusters at different compositions. The results suggest that the more stable the cluster, the higher the melting point for the 55-atom icosahedral Ag-Pd bimetallic clusters at different compositions.

The Jeanie Point complex revisited

USGS Publications Warehouse

Dumoulin, Julie A.; Miller, Martha L.

1984-01-01

The so-called Jeanie Point complex is a distinctive package of rocks within the Orca Group, a Tertiary turbidite sequence. The rocks crop out on the southeast coast of Montague Island, Prince William Sound, approximately 3 km northeast of Jeanie Point (loc. 7, fig. 44). These rocks consist dominantly of fine-grained limestone and lesser amounts of siliceous limestone, chert, tuff, mudstone, argillite, and sandstone (fig. 47). The Jeanie Point rocks also differ from those typical of the Orca Group in their fold style. Thus, the Orca Group of the area is isoclinally folded on a large scale (tens to hundreds of meters), whereas the Jeanie Point rocks are tightly folded on a 1- to 3- m-wavelength scale (differences in rock competency may be responsible for this variation in fold style).

Extending High-Order Flux Operators on Spherical Icosahedral Grids and Their Applications in the Framework of a Shallow Water Model

NASA Astrophysics Data System (ADS)

Zhang, Yi

2018-01-01

This study extends a set of unstructured third/fourth-order flux operators on spherical icosahedral grids from two perspectives. First, the fifth-order and sixth-order flux operators of this kind are further extended, and the nominally second-order to sixth-order operators are then compared based on the solid body rotation and deformational flow tests. Results show that increasing the nominal order generally leads to smaller absolute errors. Overall, the standard fifth-order scheme generates the smallest errors in limited and unlimited tests, although it does not enhance the convergence rate. Even-order operators show higher limiter sensitivity than the odd-order operators. Second, a triangular version of these high-order operators is repurposed for transporting the potential vorticity in a space-time-split shallow water framework. Results show that a class of nominally third-order upwind-biased operators generates better results than second-order and fourth-order counterparts. The increase of the potential enstrophy over time is suppressed owing to the damping effect. The grid-scale noise in the vorticity is largely alleviated, and the total energy remains conserved. Moreover, models using high-order operators show smaller numerical errors in the vorticity field because of a more accurate representation of the nonlinear Coriolis term. This improvement is especially evident in the Rossby-Haurwitz wave test, in which the fluid is highly rotating. Overall, high-order flux operators with higher damping coefficients, which essentially behave like the Anticipated Potential Vorticity Method, present better results.

Thermodynamic consideration and ground-state search of icosahedral boron subselenide B12(B1-xSex) 2 from a first-principles cluster expansion

NASA Astrophysics Data System (ADS)

Ektarawong, A.

2018-05-01

The phase stability of icosahedral boron subselenide B12(B1-xSex) 2 , where 0.5 ≤x ≤1 , is explored using a first-principles cluster expansion. The results shows that, instead of a continuous solid solution, B12(B1-xSex) 2 is thermodynamically stable as an individual line compound at the composition of B9.5Se . The ground-state configuration of B9.5Se is represented by a mixture of B12(Se-Se), B12(B-Se), and B12(Se-B) with a ratio of 1:1:1, where they form a periodic A B C A B C ⋯ stacking sequence of B12(Se-Se), B12(B-Se), and B12(Se-B) layers along the c axis of the hexagonal conventional unit cell. The structural and electronic properties of the ground-state B9.5Se are also derived and discussed. By comparing the derived ground-state properties of B9.5Se to the existing experimental data of boron subselenide B˜13Se , I proposed that the as-synthesized boron subselenide B˜13Se , as reported in the literature, has the actual composition of B9.5Se .

Group Theoretical Route to Deterministic Weyl Points in Chiral Photonic Lattices.

PubMed

Saba, Matthias; Hamm, Joachim M; Baumberg, Jeremy J; Hess, Ortwin

2017-12-01

Topological phases derived from point degeneracies in photonic band structures show intriguing and unique behavior. Previously identified band degeneracies are based on accidental degeneracies and subject to engineering on a case-by-case basis. Here we show that deterministic pseudo Weyl points with nontrivial topology and hyperconic dispersion exist at the Brillouin zone center of chiral cubic symmetries. This conceivably allows realization of topologically protected frequency isolated surface bands in 3D and n=0 properties as demonstrated for a nanoplasmonic system and a photonic crystal.

Group Theoretical Route to Deterministic Weyl Points in Chiral Photonic Lattices

NASA Astrophysics Data System (ADS)

Saba, Matthias; Hamm, Joachim M.; Baumberg, Jeremy J.; Hess, Ortwin

2017-12-01

Topological phases derived from point degeneracies in photonic band structures show intriguing and unique behavior. Previously identified band degeneracies are based on accidental degeneracies and subject to engineering on a case-by-case basis. Here we show that deterministic pseudo Weyl points with nontrivial topology and hyperconic dispersion exist at the Brillouin zone center of chiral cubic symmetries. This conceivably allows realization of topologically protected frequency isolated surface bands in 3D and n =0 properties as demonstrated for a nanoplasmonic system and a photonic crystal.

Fixing the fixed-point system—Applying Dynamic Renormalization Group to systems with long-range interactions

NASA Astrophysics Data System (ADS)

Katzav, Eytan

2013-04-01

In this paper, a mode of using the Dynamic Renormalization Group (DRG) method is suggested in order to cope with inconsistent results obtained when applying it to a continuous family of one-dimensional nonlocal models. The key observation is that the correct fixed-point dynamical system has to be identified during the analysis in order to account for all the relevant terms that are generated under renormalization. This is well established for static problems, however poorly implemented in dynamical ones. An application of this approach to a nonlocal extension of the Kardar-Parisi-Zhang equation resolves certain problems in one-dimension. Namely, obviously problematic predictions are eliminated and the existing exact analytic results are recovered.

Influence of leaching on surface composition, microstructure, and valence band of single grain icosahedral Al-Cu-Fe quasicrystal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lowe, M.; McGrath, R.; Sharma, H. R.

The use of quasicrystals as precursors to catalysts for the steam reforming of methanol is potentially one of the most important applications of these new materials. To develop application as a technology requires a detailed understanding of the microscopic behavior of the catalyst. Here, we report the effect of leaching treatments on the surface microstructure, chemical composition, and valence band of the icosahedral (i-) Al-Cu-Fe quasicrystal in an attempt to prepare a model catalyst. The high symmetry fivefold surface of a single grain i-Al-Cu-Fe quasicrystal was leached with NaOH solution for varying times, and the resulting surface was characterized bymore » x-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The leaching treatments preferentially remove Al producing a capping layer consisting of Fe and Cu oxides. The subsurface layer contains elemental Fe and Cu in addition to the oxides. The quasicrystalline bulk structure beneath remains unchanged. The subsurface gradually becomes Fe{sub 3}O{sub 4} rich with increasing leaching time. The surface after leaching exhibits micron sized dodecahedral cavities due to preferential leaching along the fivefold axis. Nanoparticles of the transition metals and their oxides are precipitated on the surface after leaching. The size of the nanoparticles is estimated by high resolution transmission microscopy to be 5-20 nm, which is in agreement with the AFM results. Selected area electron diffraction (SAED) confirms the crystalline nature of the nanoparticles. SAED further reveals the formation of an interface between the high atomic density lattice planes of nanoparticles and the quasicrystal. These results provide an important insight into the preparation of model catalysts of nanoparticles for steam reforming of methanol.« less

Functional renormalization-group approaches, one-particle (irreducible) reducible with respect to local Green’s functions, with dynamical mean-field theory as a starting point

DOE Office of Scientific and Technical Information (OSTI.GOV)

Katanin, A. A., E-mail: katanin@mail.ru

We consider formulations of the functional renormalization-group (fRG) flow for correlated electronic systems with the dynamical mean-field theory as a starting point. We classify the corresponding renormalization-group schemes into those neglecting one-particle irreducible six-point vertices (with respect to the local Green’s functions) and neglecting one-particle reducible six-point vertices. The former class is represented by the recently introduced DMF{sup 2}RG approach [31], but also by the scale-dependent generalization of the one-particle irreducible representation (with respect to local Green’s functions, 1PI-LGF) of the generating functional [20]. The second class is represented by the fRG flow within the dual fermion approach [16, 32].more » We compare formulations of the fRG approach in each of these cases and suggest their further application to study 2D systems within the Hubbard model.« less

Effectiveness of dry needling of rectus abdominis trigger points for the treatment of primary dysmenorrhoea: a randomised parallel-group trial.

PubMed

Gaubeca-Gilarranz, Alberto; Fernández-de-Las-Peñas, César; Medina-Torres, José Raúl; Seoane-Ruiz, José M; Company-Palonés, Aurelio; Cleland, Joshua A; Arias-Buría, Jose L

2018-05-02

To compare the effectiveness of trigger point dry needling (TrP-DN) versus placebo needling, relative to an untreated control group, on pain and quality of life in primary dysmenorrhoea. In this randomised, single blind, parallel-group trial, 56 females with primary dysmenorrhoea were randomly allocated to TrP-DN (n=19), placebo needling (n=18) or no treatment (n=19). Patients in both groups were asked to undertake a stretching exercise of the rectus abdominis daily. The needling group received a single session of TrP-DN to trigger points (TrPs) in the rectus abdominis, and the placebo group received placebo needling. The primary outcome was pain intensity (visual analogue scale). Secondary outcomes were quality of life, use of non-steroidal anti-inflammatory drugs, the number of days with pain, and self-perceived improvement, measured using a Global Rate of Change. Outcomes were assessed at baseline, and 1 and 2 months after the treatment. Females receiving TrP-DN exhibited greater decreases (P<0.001) in pain than those receiving placebo (1 month: Δ-19.8 mm, 25.9 to -13.7; 2 months: Δ-26.0 mm, -33.1 to -18.9) or assigned to the untreated control group (1 month: Δ-26.0mm, -32.5 to -19.5; 2 months: Δ-20.1 mm, -26.4 to -13.8). Females in the TrP-DN group also exhibited a greater decrease in the amount of medications (P<0.001). No differences in the number of days with pain or quality of life were found (all P>0.1). This trial suggests that a single session of TrP-DN of the rectus abdominis combined with stretching was more effective than placebo needling and stretching alone at reducing pain and the amount of medication used in primary dysmenorrhoea. ACTRN12616000170426. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Anterior midline point stop device (AMPS) in the treatment of myogenous TMDs: comparison with the stabilization splint and control group.

PubMed

Al Quran, Firas A M; Kamal, Mudar S

2006-06-01

Two occlusal splints, the full-arch stabilization splint and the anterior midline point stop (AMPS) device, were evaluated for their efficiency in relieving myogenous temporomandibular disorders (TMD). One hundred and fourteen patients with myogenous TMD were distributed into 3 groups. The first group was treated with the AMPS device, the second with the stabilization splint, and the third group was the control group. Pain intensity was scored using the visual analogue scale before treatment and 1 month and 3 months after treatment. Statistical Package for the Social Sciences (SPSS, Chicago, Ill) and multiple comparisons tests were used to compare results before and after treatment and to compare the groups. The use of AMPS device in the first group resulted in a significant improvement after 1 month and 3 months (P < or = .001) and showed a 56.66% pain reduction. A significant improvement was also noticed in the second group (P = .001) with a 47.71% pain reduction. Although pain reduction percentage appeared more in the first group, this was not statistically significant. There was a highly significant difference between groups treated with both kinds of splints and the control group. It was concluded that both types of occlusal splints are beneficial to patients with myogenous TMD.

Access to Liver Transplantation in Different ABO-Blood Groups and "Exceptions Points" in a Model for End-Stage Liver Disease Allocation System: A Brazilian Single-Center Study.

PubMed

Martino, R B; Waisberg, D R; Dias, A P M; Inoue, V B S; Arantes, R M; Haddad, L B P; Rocha-Santos, V; Pinheiro, R S N; Nacif, L S; D'Albuquerque, L A C

2018-04-01

In the Model for End-Stage Liver Disease (MELD) system, patients with "MELD exceptions" points may have unfair privilege in the competition for liver grafts. Furthermore, organ distribution following identical ABO blood types may also result in unjust organ allocation. The aim of this study was to investigate access to liver transplantation in a tertiary Brazilian center, regarding "MELD exceptions" situations and among ABO-blood groups. A total of 465 adult patients on the liver waitlist from August 2015 to August 2016 were followed up until August 2017. Patients were divided into groups according to ABO-blood type and presence of "exceptions points." No differences in outcomes were observed among ABO-blood groups. However, patients from B and AB blood types spent less time on the list than patients from A and O groups (median, 46, 176, 415, and 401 days, respectively; P = .03). "Exceptions points" were granted for 141 patients (30.1%), hepatocellular carcinoma being the most common reason (52.4%). Patients with "exceptions points" showed higher transplantation rate, lower mortality on the list, and lower delta-MELD than non-exceptions patients (56.7% vs 19.1% [P < .01]; 18.4% vs 38.5% [P < .01], and 2.0 ± 2.6 vs 6.9 ± 7.0 [P < .01], respectively). Patients with refractory ascites had a higher mortality rate than those with other "exceptions" or without (48%). The MELD system provides equal access to liver transplantation among ABO-blood types, despite shorter time on the waitlist for AB and B groups. The current MELD exception system provides advantages for candidates with "exception points," resulting in superior outcomes compared with those without exceptions. Copyright © 2018 Elsevier Inc. All rights reserved.

Critical Point Facility (CPE) Group in the Spacelab Payload Operations Control Center (SL POCC)

NASA Technical Reports Server (NTRS)

1992-01-01

The primary payload for Space Shuttle Mission STS-42, launched January 22, 1992, was the International Microgravity Laboratory-1 (IML-1), a pressurized manned Spacelab module. The goal of IML-1 was to explore in depth the complex effects of weightlessness of living organisms and materials processing. Around-the-clock research was performed on the human nervous system's adaptation to low gravity and effects of microgravity on other life forms such as shrimp eggs, lentil seedlings, fruit fly eggs, and bacteria. Materials processing experiments were also conducted, including crystal growth from a variety of substances such as enzymes, mercury iodide, and a virus. The Huntsville Operations Support Center (HOSC) Spacelab Payload Operations Control Center (SL POCC) at the Marshall Space Flight Center (MSFC) was the air/ground communication channel used between the astronauts and ground control teams during the Spacelab missions. Featured is the Critical Point Facility (CPE) group in the SL POCC during STS-42, IML-1 mission.

Theory of morphological transformation of viral capsid shell during the maturation process in the HK97 bacteriophage and similar viruses

NASA Astrophysics Data System (ADS)

Konevtsova, O. V.; Lorman, V. L.; Rochal, S. B.

2016-05-01

We consider the symmetry and physical origin of collective displacement modes playing a crucial role in the morphological transformation during the maturation of the HK97 bacteriophage and similar viruses. It is shown that the experimentally observed hexamer deformation and pentamer twist in the HK97 procapsid correspond to the simplest irreducible shear strain mode of a spherical shell. We also show that the icosahedral faceting of the bacteriophage capsid shell is driven by the simplest irreducible radial displacement field. The shear field has the rotational icosahedral symmetry group I while the radial field has the full icosahedral symmetry Ih. This difference makes their actions independent. The radial field sign discriminates between the icosahedral and the dodecahedral shapes of the faceted capsid shell, thus making the approach relevant not only for the HK97-like viruses but also for the parvovirus family. In the frame of the Landau-Ginzburg formalism we propose a simple phenomenological model valid for the first reversible step of the HK97 maturation process. The calculated phase diagram illustrates the discontinuous character of the virus shape transformation. The characteristics of the virus shell faceting and expansion obtained in the in vitro and in vivo experiments are related to the decrease in the capsid shell thickness and to the increase of the internal capsid pressure.

End-group-functionalized poly(N,N-diethylacrylamide) via free-radical chain transfer polymerization: Influence of sulfur oxidation and cyclodextrin on self-organization and cloud points in water

PubMed Central

Reinelt, Sebastian; Steinke, Daniel

2014-01-01

Summary In this work we report the synthesis of thermo-, oxidation- and cyclodextrin- (CD) responsive end-group-functionalized polymers, based on N,N-diethylacrylamide (DEAAm). In a classical free-radical chain transfer polymerization, using thiol-functionalized 4-alkylphenols, namely 3-(4-(1,1-dimethylethan-1-yl)phenoxy)propane-1-thiol and 3-(4-(2,4,4-trimethylpentan-2-yl)phenoxy)propane-1-thiol, poly(N,N-diethylacrylamide) (PDEAAm) with well-defined hydrophobic end-groups is obtained. These end-group-functionalized polymers show different cloud point values, depending on the degree of polymerization and the presence of randomly methylated β-cyclodextrin (RAMEB-CD). Additionally, the influence of the oxidation of the incorporated thioether linkages on the cloud point is investigated. The resulting hydrophilic sulfoxides show higher cloud point values for the lower critical solution temperature (LCST). A high degree of functionalization is supported by 1H NMR-, SEC-, FTIR- and MALDI–TOF measurements. PMID:24778720

[Clinical observation of sleeping disorder in children with encephalopathy treated with acupuncture at head points and seed-pressure at ear points].

PubMed

Lai, Shugui; Wu, Qiang; Chen, Lanfang; Huang, Qianru; Zhang, Xuejun

2015-07-01

To compare the difference of clinical efficacy on sleeping disorder in the children with encephalopathy between the combined therapy of acupuncture at head points and seed-pressure at ear points and the simple acupuncture at head points. Thirty cases of sleeping disorder induced by encephalopathy werei randomized into an observation group and a control group, 15 cases in each one. In the observation group, the combined therapy of acupuncture at head points and seed-pressure at ear points was adopted. The head points in cluded Sishencong (EX-HN 1), Shenting (GV 24) and Benshen (GB 13). The ear points were the positive reactive sites in the cymba and cavum conchae. In the control group, acupuncture was applied simply to the acupoints on the head. The treatment was given once on every Tuesday and Friday a week separately, 30 min each time. Totally, 16 treatments were required. Children's sleeping habit questionnaire (CSHQ) was used to observe the sleep improvements and the efficacy in the patients of the two groups. In the observation group, the results of sleep resistance, sleep anxiety, night sleep wake, parasomnias, sleep dyspnea, daytime somnolence and the total score after treatment were all improved apparently as compared with those before treatment (all P<0. 05). In the control group, the results of night sleep wake, parasomnias, daytime somnolence and the total score after treatment were improved apparently than those before treatment (all P<0. 05). In the observation group, the results of sleep resistance, sleep dyspnea and the total score after treatment were better than those in the control group (all P<0. 05) and the scores of sleep anxiety and daytime somnolence in the control group were better than those in the observation group after treatment (both P<0. 05). The combined therapy of acupuncture at head points and seed-pressure at the positive reactive sites in the cymba and cavum conchae achieves the superior efficacy on sleep resistance and sleep

Model Parameter Estimation Using Ensemble Data Assimilation: A Case with the Nonhydrostatic Icosahedral Atmospheric Model NICAM and the Global Satellite Mapping of Precipitation Data

NASA Astrophysics Data System (ADS)

Kotsuki, Shunji; Terasaki, Koji; Yashiro, Hasashi; Tomita, Hirofumi; Satoh, Masaki; Miyoshi, Takemasa

2017-04-01

This study aims to improve precipitation forecasts from numerical weather prediction (NWP) models through effective use of satellite-derived precipitation data. Kotsuki et al. (2016, JGR-A) successfully improved the precipitation forecasts by assimilating the Japan Aerospace eXploration Agency (JAXA)'s Global Satellite Mapping of Precipitation (GSMaP) data into the Nonhydrostatic Icosahedral Atmospheric Model (NICAM) at 112-km horizontal resolution. Kotsuki et al. mitigated the non-Gaussianity of the precipitation variables by the Gaussian transform method for observed and forecasted precipitation using the previous 30-day precipitation data. This study extends the previous study by Kotsuki et al. and explores an online estimation of model parameters using ensemble data assimilation. We choose two globally-uniform parameters, one is the cloud-to-rain auto-conversion parameter of the Berry's scheme for large scale condensation and the other is the relative humidity threshold of the Arakawa-Schubert cumulus parameterization scheme. We perform the online-estimation of the two model parameters with an ensemble transform Kalman filter by assimilating the GSMaP precipitation data. The estimated parameters improve the analyzed and forecasted mixing ratio in the lower troposphere. Therefore, the parameter estimation would be a useful technique to improve the NWP models and their forecasts. This presentation will include the most recent progress up to the time of the symposium.

Structure of epsilon15 bacteriophage reveals genome organization and DNA packaging/injection apparatus

NASA Astrophysics Data System (ADS)

Jiang, Wen; Chang, Juan; Jakana, Joanita; Weigele, Peter; King, Jonathan; Chiu, Wah

2006-02-01

The critical viral components for packaging DNA, recognizing and binding to host cells, and injecting the condensed DNA into the host are organized at a single vertex of many icosahedral viruses. These component structures do not share icosahedral symmetry and cannot be resolved using a conventional icosahedral averaging method. Here we report the structure of the entire infectious Salmonella bacteriophage epsilon15 (ref. 1) determined from single-particle cryo-electron microscopy, without icosahedral averaging. This structure displays not only the icosahedral shell of 60 hexamers and 11 pentamers, but also the non-icosahedral components at one pentameric vertex. The densities at this vertex can be identified as the 12-subunit portal complex sandwiched between an internal cylindrical core and an external tail hub connecting to six projecting trimeric tailspikes. The viral genome is packed as coaxial coils in at least three outer layers with ~90 terminal nucleotides extending through the protein core and the portal complex and poised for injection. The shell protein from icosahedral reconstruction at higher resolution exhibits a similar fold to that of other double-stranded DNA viruses including herpesvirus, suggesting a common ancestor among these diverse viruses. The image reconstruction approach should be applicable to studying other biological nanomachines with components of mixed symmetries.

Reduction of variance in spectral estimates for correction of ultrasonic aberration.

PubMed

Astheimer, Jeffrey P; Pilkington, Wayne C; Waag, Robert C

2006-01-01

A variance reduction factor is defined to describe the rate of convergence and accuracy of spectra estimated from overlapping ultrasonic scattering volumes when the scattering is from a spatially uncorrelated medium. Assuming that the individual volumes are localized by a spherically symmetric Gaussian window and that centers of the volumes are located on orbits of an icosahedral rotation group, the factor is minimized by adjusting the weight and radius of each orbit. Conditions necessary for the application of the variance reduction method, particularly for statistical estimation of aberration, are examined. The smallest possible value of the factor is found by allowing an unlimited number of centers constrained only to be within a ball rather than on icosahedral orbits. Computations using orbits formed by icosahedral vertices, face centers, and edge midpoints with a constraint radius limited to a small multiple of the Gaussian width show that a significant reduction of variance can be achieved from a small number of centers in the confined volume and that this reduction is nearly the maximum obtainable from an unlimited number of centers in the same volume.

Fermion-induced quantum critical points.

PubMed

Li, Zi-Xiang; Jiang, Yi-Fan; Jian, Shao-Kai; Yao, Hong

2017-08-22

A unified theory of quantum critical points beyond the conventional Landau-Ginzburg-Wilson paradigm remains unknown. According to Landau cubic criterion, phase transitions should be first-order when cubic terms of order parameters are allowed by symmetry in the Landau-Ginzburg free energy. Here, from renormalization group analysis, we show that second-order quantum phase transitions can occur at such putatively first-order transitions in interacting two-dimensional Dirac semimetals. As such type of Landau-forbidden quantum critical points are induced by gapless fermions, we call them fermion-induced quantum critical points. We further introduce a microscopic model of SU(N) fermions on the honeycomb lattice featuring a transition between Dirac semimetals and Kekule valence bond solids. Remarkably, our large-scale sign-problem-free Majorana quantum Monte Carlo simulations show convincing evidences of a fermion-induced quantum critical points for N = 2, 3, 4, 5 and 6, consistent with the renormalization group analysis. We finally discuss possible experimental realizations of the fermion-induced quantum critical points in graphene and graphene-like materials.Quantum phase transitions are governed by Landau-Ginzburg theory and the exceptions are rare. Here, Li et al. propose a type of Landau-forbidden quantum critical points induced by gapless fermions in two-dimensional Dirac semimetals.

Extending high-order flux operators on spherical icosahedral grids and their application in a Shallow Water Model for transporting the Potential Vorticity

NASA Astrophysics Data System (ADS)

Zhang, Y.

2017-12-01

The unstructured formulation of the third/fourth-order flux operators used by the Advanced Research WRF is extended twofold on spherical icosahedral grids. First, the fifth- and sixth-order flux operators of WRF are further extended, and the nominally second- to sixth-order operators are then compared based on the solid body rotation and deformational flow tests. Results show that increasing the nominal order generally leads to smaller absolute errors. Overall, the fifth-order scheme generates the smallest errors in limited and unlimited tests, although it does not enhance the convergence rate. The fifth-order scheme also exhibits smaller sensitivity to the damping coefficient than the third-order scheme. Overall, the even-order schemes have higher limiter sensitivity than the odd-order schemes. Second, a triangular version of these high-order operators is repurposed for transporting the potential vorticity in a space-time-split shallow water framework. Results show that a class of nominally third-order upwind-biased operators generates better results than second- and fourth-order counterparts. The increase of the potential enstrophy over time is suppressed owing to the damping effect. The grid-scale noise in the vorticity is largely alleviated, and the total energy remains conserved. Moreover, models using high-order operators show smaller numerical errors in the vorticity field because of a more accurate representation of the nonlinear Coriolis term. This improvement is especially evident in the Rossby-Haurwitz wave test, in which the fluid is highly rotating. Overall, flux operators with higher damping coefficients, which essentially behaves like the Anticipated Potential Vorticity Method, present optimal results.

Average crystal structure(s) of the embedded meta stable η‧-phase in the Al-Mg-Zn system

NASA Astrophysics Data System (ADS)

Bøvik Larsen, Helge; Thorkildsen, Gunnar; Natland, Sølvi; Pattison, Philip

2014-05-01

Meta stable embedded nano-sized ?-particles within a single grain extracted from an alloy having the nominal composition ? have been examined with X-ray diffraction. By applying the orientational and metric relationships that exist between the hexagonal unit cell of the ?-particles and the cubic unit cell of the Al-matrix, it has been proven possible to directly collect diffracted intensity data from the ?-particle ensemble. This has been done using synchrotron radiation and a ?-diffractometer having a scintillator point detector setup. The approach has resulted in improved data quality compared to previous experiments. The interpretation of the data set, based on a combination of Patterson syntheses, direct methods and geometrical restraints, yielded two possible average structural representations: one Al-rich with the approximate stoichiometric composition ? and one Al-depleted with approximate stoichiometric composition ?. Both structures are realized in the same space group, ?, and are most probably superimposed in the crystalline system examined. The geometries are discussed within the atomic environment approach where icosahedral or near-icosahedral configurations are encountered. Comparison with previous published models and the equilibrium structure reveals a main difference related to the distribution of the Zn-sites in the unit cell. A possible transformation path is also suggested. Various aspects and challenges regarding data collection, data reduction and data quality are specifically addressed.

The diversity of the orthoreoviruses: molecular taxonomy and phylogentic divides.

USDA-ARS?s Scientific Manuscript database

The family Reoviridae is a diverse group of viruses with double-stranded ribonucleic acid (RNA) genomes contained within icosahedral, layered protein capsids. Within the Reoviridae, the Orthoreovirus genus includes viruses that infect reptiles, birds and mammals (including humans). Recent sequencing...

Media Criticism Group Speech

ERIC Educational Resources Information Center

Ramsey, E. Michele

2004-01-01

Objective: To integrate speaking practice with rhetorical theory. Type of speech: Persuasive. Point value: 100 points (i.e., 30 points based on peer evaluations, 30 points based on individual performance, 40 points based on the group presentation), which is 25% of course grade. Requirements: (a) References: 7-10; (b) Length: 20-30 minutes; (c)…

Structural characterization of alpha-terminal group of natural rubber. 2. Decomposition of branch-points by phospholipase and chemical treatments.

PubMed

Tarachiwin, Lucksanaporn; Sakdapipanich, Jitladda; Ute, Koichi; Kitayama, Tatsuki; Tanaka, Yasuyuki

2005-01-01

The treatment of deproteinized natural rubber (DPNR) latex with phospholipases A(2), B, C, and D decreased significantly the long-chain fatty acid ester contents in DPNR and also the molecular weight and Higgins' k' constant, except for phospholipase D treatment. This indicates the presence of phospholipid molecules in NR, which combine rubber molecules together. Transesterification of DPNR resulted in the decomposition of the functional group at the terminal chain-end (alpha-terminal), including phospholipids and formed linear rubber molecules. The addition of small amounts of ethanol into the DPNR solution reduced the molecular weight and shifted the molecular weight distribution (MWD) comparable to that of transesterified DPNR (TE-DPNR). The addition of diammonium hydrogen phosphate into DPNR-latex in order to remove Mg2+ ions yielded a slight decrease in molecular weight and a slight shift in MWD. The phospholipids are expected to link with mono- and diphosphate groups at the alpha-terminal by hydrogen bonding and/or ionic linkages. The decrease in the molecular weight and Huggins' k' constant of DPNR demonstrates the formation of linear molecules after decomposition of branch-points by this treatment, showing that phospholipids participate in the branching formation of NR. The branch-points formed at the alpha-terminus are postulated to originate predominantly by the association of phospholipids via micelle formation of long-chain fatty acid esters and hydrogen bonding between polar headgroups of phospholipids.

A diagnostic interface for the ICOsahedral Non-hydrostatic (ICON) modelling framework based on the Modular Earth Submodel System (MESSy v2.50)

NASA Astrophysics Data System (ADS)

Kern, Bastian; Jöckel, Patrick

2016-10-01

Numerical climate and weather models have advanced to finer scales, accompanied by large amounts of output data. The model systems hit the input and output (I/O) bottleneck of modern high-performance computing (HPC) systems. We aim to apply diagnostic methods online during the model simulation instead of applying them as a post-processing step to written output data, to reduce the amount of I/O. To include diagnostic tools into the model system, we implemented a standardised, easy-to-use interface based on the Modular Earth Submodel System (MESSy) into the ICOsahedral Non-hydrostatic (ICON) modelling framework. The integration of the diagnostic interface into the model system is briefly described. Furthermore, we present a prototype implementation of an advanced online diagnostic tool for the aggregation of model data onto a user-defined regular coarse grid. This diagnostic tool will be used to reduce the amount of model output in future simulations. Performance tests of the interface and of two different diagnostic tools show, that the interface itself introduces no overhead in form of additional runtime to the model system. The diagnostic tools, however, have significant impact on the model system's runtime. This overhead strongly depends on the characteristics and implementation of the diagnostic tool. A diagnostic tool with high inter-process communication introduces large overhead, whereas the additional runtime of a diagnostic tool without inter-process communication is low. We briefly describe our efforts to reduce the additional runtime from the diagnostic tools, and present a brief analysis of memory consumption. Future work will focus on optimisation of the memory footprint and the I/O operations of the diagnostic interface.

Multiplicity: discussion points from the Statisticians in the Pharmaceutical Industry multiplicity expert group.

PubMed

Phillips, Alan; Fletcher, Chrissie; Atkinson, Gary; Channon, Eddie; Douiri, Abdel; Jaki, Thomas; Maca, Jeff; Morgan, David; Roger, James Henry; Terrill, Paul

2013-01-01

In May 2012, the Committee of Health and Medicinal Products issued a concept paper on the need to review the points to consider document on multiplicity issues in clinical trials. In preparation for the release of the updated guidance document, Statisticians in the Pharmaceutical Industry held a one-day expert group meeting in January 2013. Topics debated included multiplicity and the drug development process, the usefulness and limitations of newly developed strategies to deal with multiplicity, multiplicity issues arising from interim decisions and multiregional development, and the need for simultaneous confidence intervals (CIs) corresponding to multiple test procedures. A clear message from the meeting was that multiplicity adjustments need to be considered when the intention is to make a formal statement about efficacy or safety based on hypothesis tests. Statisticians have a key role when designing studies to assess what adjustment really means in the context of the research being conducted. More thought during the planning phase needs to be given to multiplicity adjustments for secondary endpoints given these are increasing in importance in differentiating products in the market place. No consensus was reached on the role of simultaneous CIs in the context of superiority trials. It was argued that unadjusted intervals should be employed as the primary purpose of the intervals is estimation, while the purpose of hypothesis testing is to formally establish an effect. The opposing view was that CIs should correspond to the test decision whenever possible. Copyright © 2013 John Wiley & Sons, Ltd.

High prevalence of the point mutation in exon 6 of the xeroderma pigmentosum group A-complementing (XPAC) gene in xeroderma pigmentosum group A patients in Tunisia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nishigori, Chikako; Imamura, Sadao; Yagi, Takashi

1993-11-01

Xeroderma pigmentosum (XP) patients in Tunisia who belong to the genetic complementation group A (XPA) have milder skin symptoms than do Japanese XPA patients. Such difference in the clinical features might be caused by the difference in the site of mutation in the XP A-complementing (XPAC) gene. The purpose of this study is to identify the genetic alterations in the XPAC gene in the Tunisian XPA patients and to investigate the relationship between the clinical symptoms and the genetic alterations. Three sites of mutation in the XPAC gene have been identified in the Japanese XPA patients, and about 85% ofmore » them have a G [yields] C point mutation at the splicing acceptor site of intron 3. The authors found that six (86%) of seven Tunisian XPA patients had a nonsense mutation in codon 228 in exon 6, because of a CGA [yields] TGA point mutation, which can be detected by the HphI RFLP. This type of mutation is the same as those found in two Japanese XPA patients with mild clinical RFLP. Milder skin symptoms in the XPA patients in Tunisia than in those in Japan, despite mostly sunny weather and the unsatisfactory sun protection in Tunisia, should be due to the difference in the mutation site. 11 refs., 2 figs., 2 tabs.« less

Vanishing Point Extraction and Refinement for Robust Camera Calibration

PubMed Central

Tsai, Fuan

2017-01-01

This paper describes a flexible camera calibration method using refined vanishing points without prior information. Vanishing points are estimated from human-made features like parallel lines and repeated patterns. With the vanishing points extracted from the three mutually orthogonal directions, the interior and exterior orientation parameters can be further calculated using collinearity condition equations. A vanishing point refinement process is proposed to reduce the uncertainty caused by vanishing point localization errors. The fine-tuning algorithm is based on the divergence of grouped feature points projected onto the reference plane, minimizing the standard deviation of each of the grouped collinear points with an O(1) computational complexity. This paper also presents an automated vanishing point estimation approach based on the cascade Hough transform. The experiment results indicate that the vanishing point refinement process can significantly improve camera calibration parameters and the root mean square error (RMSE) of the constructed 3D model can be reduced by about 30%. PMID:29280966

Nanosized (mu12-Pt)Pd164-xPtx(CO)72(PPh3)20 (x approximately 7) containing Pt-centered four-shell 165-atom Pd-Pt core with unprecedented intershell bridging carbonyl ligands: comparative analysis of icosahedral shell-growth patterns with geometrically related Pd145(CO)x(PEt3)30 (x approximately 60) containing capped three-shell Pd145 core.

PubMed

Mednikov, Evgueni G; Jewell, Matthew C; Dahl, Lawrence F

2007-09-19

Presented herein are the preparation and crystallographic/microanalytical/magnetic/spectroscopic characterization of the Pt-centered four-shell 165-atom Pd-Pt cluster, (mu(12)-Pt)Pd(164-x)Pt(x)(CO)(72)(PPh(3))(20) (x approximately 7), 1, that replaces the geometrically related capped three-shell icosahedral Pd(145) cluster, Pd(145)(CO)(x)(PEt(3))(30) (x approximately 60), 2, as the largest crystallographically determined discrete transition metal cluster with direct metal-metal bonding. A detailed comparison of their shell-growth patterns gives rise to important stereochemical implications concerning completely unexpected structural dissimilarities as well as similarities and provides new insight concerning possible synthetic approaches for generation of multi-shell metal clusters. 1 was reproducibly prepared in small yields (<10%) from the reaction of Pd(10)(CO)(12)(PPh(3))(6) with Pt(CO)(2)(PPh(3))(2). Its 165-atom metal-core geometry and 20 PPh(3) and 72 CO ligands were established from a low-temperature (100 K) CCD X-ray diffraction study. The well-determined crystal structure is attributed largely to 1 possessing cubic T(h) (2/m3) site symmetry, which is the highest crystallographic subgroup of the noncrystallographic pseudo-icosahedral I(h) (2/m35) symmetry. The "full" four-shell Pd-Pt anatomy of 1 consists of: (a) shell 1 with the centered (mu(12)-Pt) atom encapsulated by the 12-atom icosahedral Pt(x)Pd(12-x) cage, x = 1.2(3); (b) shell 2 with the 42-atom nu(2) icosahedral Pt(x)Pd(42-x) cage, x = 3.5(5); (c) shell 3 with the anti-Mackay 60-atom semi-regular rhombicosidodecahedral Pt(x)Pd(60-x) cage, x = 2.2(6); (d) shell 4 with the 50-atom nu(2) pentagonal dodecahedral Pd(50) cage. The total number of crystallographically estimated Pt atoms, 8 +/- 3, which was obtained from least-squares (Pt(x)/Pd(1-x))-occupancy analysis of the X-ray data that conclusively revealed the central atom to be pure Pt (occupancy factor, x = 1.00(3)), is fortuitously in agreement

Early repolarization, localization of J point elevation on ECG and arrhythmias.

PubMed

Matoshvili, Z; Petriashvili, Sh; Archvadze, A; Azaladze, I

2015-04-01

Final aim of this observational study was to determine correlation between localization of J point elevation and number of premature ventricular beats. The 52 patients (19-68 years old; 31 men and 21 women) were divided in two groups based on localization of J point elevation. First Group - 9 patients (5 men and 4 women) with J-point elevation ≥1 mm in ≥2 contiguous inferior and/or lateral leads on a standard 12-lead ECG reading, Second Group - other 43 (26 men and 17 women) patients with another localization of J point elevation. Total summarized number of premature ventricular contractions for each group was compared and analyzed. The results of the study shows that the number of premature ventricular beats in first group was 61% higher. Thus, in our opinion J-point elevation ≥1 mm in ≥2 contiguous inferior and/or lateral leads, is more arrhythmogenic. Data shows that this difference is statistically significant.

A maximum power point prediction method for group control of photovoltaic water pumping systems based on parameter identification

NASA Astrophysics Data System (ADS)

Chen, B.; Su, J. H.; Guo, L.; Chen, J.

2017-06-01

This paper puts forward a maximum power estimation method based on the photovoltaic array (PVA) model to solve the optimization problems about group control of the PV water pumping systems (PVWPS) at the maximum power point (MPP). This method uses the improved genetic algorithm (GA) for model parameters estimation and identification in view of multi P-V characteristic curves of a PVA model, and then corrects the identification results through least square method. On this basis, the irradiation level and operating temperature under any condition are able to estimate so an accurate PVA model is established and the MPP none-disturbance estimation is achieved. The simulation adopts the proposed GA to determine parameters, and the results verify the accuracy and practicability of the methods.

Carbon Dioxide Compensation Points of Flowering Plants 1

PubMed Central

Krenzer, Eugene G.; Moss, Dale N.; Crookston, R. Kent

1975-01-01

Carbon dioxide compensation points of several hundred species of monocotyledons and dicotyledons have been measured during the course of various experiments in our laboratory over a period of several years. These have been classified into two groups: high, compensation points of 40 μl/l or greater; and low, compensation points of 10 μl/l or less. They are listed alphabetically both by families and species for monocotyledons and dicotyledons. Only two species did not unequivocally fit into the above established groups. These were Moricandia arvensis (L.) DC., which had an average compensation point of 26 μl/l and Panicum milioides Nees ex Trin., which was variable, but most often equilibrated between 12 to 20 μl/l CO2. PMID:16659272

Assisting People with Developmental Disabilities Improve Their Collaborative Pointing Efficiency with a Multiple Cursor Automatic Pointing Assistive Program

ERIC Educational Resources Information Center

Shih, Ching-Hsiang; Cheng, Hsiao-Fen; Li, Chia-Chun; Shih, Ching-Tien; Chiang, Ming-Shan

2010-01-01

This study evaluated whether four persons (two groups) with developmental disabilities would be able to improve their collaborative pointing performance through a Multiple Cursor Automatic Pointing Assistive Program (MCAPAP) with a newly developed mouse driver (i.e., a new mouse driver replaces standard mouse driver, and is able to…

Tinnitus retraining therapy: mixing point and total masking are equally effective.

PubMed

Tyler, Richard S; Noble, William; Coelho, Claudia Barros; Ji, Haihong

2012-01-01

Habituation to tinnitus cannot occur with total masking, an argument made by proponents of "tinnitus retraining therapy." We also compared the effectiveness of retraining therapy with mixing-point masking, total masking, and with counseling alone. Forty-eight tinnitus patients were randomly assigned to one of three groups: counseling, counseling plus bilateral noise generators set to completely mask the tinnitus, or counseling plus bilateral noise generators with a focus on the mixing point (partial masking just below total masking). A picture-based counseling protocol was used to assist in providing similar counseling among all three groups. The Tinnitus Handicap Questionnaire was administered before and after about 12 months of treatment. After 12 months, in the counseling group, three of 18 patients benefited significantly, in the mixing-point group, six of 19 patients benefited, and in the total masking group, four of 11 patients benefited from the treatment. The average decrease in the questionnaire was 16.7% for the counseling group, 31.6% for the retraining group, and 36.4% for the total masking group. No significant average differences among groups were observed. One premise of retraining therapy is incorrect; a focus on mixing-point masking is not required for habituation.

Relative Critical Points

NASA Astrophysics Data System (ADS)

Lewis, Debra

2013-05-01

Relative equilibria of Lagrangian and Hamiltonian systems with symmetry are critical points of appropriate scalar functions parametrized by the Lie algebra (or its dual) of the symmetry group. Setting aside the structures - symplectic, Poisson, or variational - generating dynamical systems from such functions highlights the common features of their construction and analysis, and supports the construction of analogous functions in non-Hamiltonian settings. If the symmetry group is nonabelian, the functions are invariant only with respect to the isotropy subgroup of the given parameter value. Replacing the parametrized family of functions with a single function on the product manifold and extending the action using the (co)adjoint action on the algebra or its dual yields a fully invariant function. An invariant map can be used to reverse the usual perspective: rather than selecting a parametrized family of functions and finding their critical points, conditions under which functions will be critical on specific orbits, typically distinguished by isotropy class, can be derived. This strategy is illustrated using several well-known mechanical systems - the Lagrange top, the double spherical pendulum, the free rigid body, and the Riemann ellipsoids - and generalizations of these systems.

Functional renormalization group for the U (1 )-T56 tensorial group field theory with closure constraint

NASA Astrophysics Data System (ADS)

Lahoche, Vincent; Ousmane Samary, Dine

2017-02-01

This paper is focused on the functional renormalization group applied to the T56 tensor model on the Abelian group U (1 ) with closure constraint. For the first time, we derive the flow equations for the couplings and mass parameters in a suitable truncation around the marginal interactions with respect to the perturbative power counting. For the second time, we study the behavior around the Gaussian fixed point, and show that the theory is nonasymptotically free. Finally, we discuss the UV completion of the theory. We show the existence of several nontrivial fixed points, study the behavior of the renormalization group flow around them, and point out evidence in favor of an asymptotically safe theory.

The Crystallographic Structure of Panicum Mosaic Virus (PMV)

PubMed Central

Makino, Debora L.; Larson, Steven B.; McPherson, Alexander

2012-01-01

The structure of Panicum Mosaic Virus (PMV) was determined by X-ray diffraction analysis to 2.9 Å resolution. The crystals were of pseudo symmetry F23; the true crystallographic unit cell was of space group P21 with a=411.7 Å, b=403.9 Å and c=412.5 Å, with β=89.7°. The asymmetric unit was two entire T=3 virus particles, or 360 protein subunits. The structure was solved by conventional molecular replacement from two distant homologues, Cocksfoot Mottle Virus (CfMV) and Tobacco Necrosis Virus (TNV), of ~20% sequence identity followed by phase extension. The model was initially refined with exact icosahedral constraints and then with icosahedral restraints. The virus has Ca++ ions octahedrally coordinated by six aspartic acid residues on quasi threefold axes, which is completely different than for either CfMV or TNV. Amino terminal residues 1–53, 1–49 and 1-21 of the A, B and C subunits, respectively, and the four C-terminal residues (239-242) are not visible in electron density maps. The additional ordered residues of the C chain form a prominent “arm” that intertwines with symmetry equivalent “arms” at icosahedral threefold axes, as was seen in both CfMV and TNV. A 17 nucleotide hairpin segment of genomic RNA is icosahedrally ordered and bound at 60 equivalent sites at quasi twofold A–B subunit interfaces at the interior surface of the capsid. This segment of RNA may serve as a conformational switch for coat protein subunits, as has been proposed for similar RNA segments in other viruses. PMID:23123270

An Analytical Approach for Relating Boiling Points of Monofunctional Organic Compounds to Intermolecular Forces

ERIC Educational Resources Information Center

Struyf, Jef

2011-01-01

The boiling point of a monofunctional organic compound is expressed as the sum of two parts: a contribution to the boiling point due to the R group and a contribution due to the functional group. The boiling point in absolute temperature of the corresponding RH hydrocarbon is chosen for the contribution to the boiling point of the R group and is a…

Smooth Scaling of Valence Electronic Properties in Fullerenes: From One Carbon Atom, to C60, to Graphene

DTIC Science & Technology

2012-09-18

Smooth scaling of valence electronic properties in fullerenes: from one carbon atom , to C60, to graphene Greyson R. Lewis,1 William E. Bunting,1...pacitance scaling lines of the fullerenes. Lastly, it is found that points representing the carbon atom and the graphene limit lie on scaling lines for...icosahedral fullerenes, so their quantum capacitances and their detachment energies scale smoothly from one C atom , through C60, to graphene. I

Multicritical points for spin-glass models on hierarchical lattices.

PubMed

Ohzeki, Masayuki; Nishimori, Hidetoshi; Berker, A Nihat

2008-06-01

The locations of multicritical points on many hierarchical lattices are numerically investigated by the renormalization group analysis. The results are compared with an analytical conjecture derived by using the duality, the gauge symmetry, and the replica method. We find that the conjecture does not give the exact answer but leads to locations slightly away from the numerically reliable data. We propose an improved conjecture to give more precise predictions of the multicritical points than the conventional one. This improvement is inspired by a different point of view coming from the renormalization group and succeeds in deriving very consistent answers with many numerical data.

Structure-Based Mutagenesis of Sulfolobus Turreted Icosahedral Virus B204 Reveals Essential Residues in the Virion-Associated DNA-Packaging ATPase.

PubMed

Dellas, Nikki; Snyder, Jamie C; Dills, Michael; Nicolay, Sheena J; Kerchner, Keshia M; Brumfield, Susan K; Lawrence, C Martin; Young, Mark J

2015-12-23

Sulfolobus turreted icosahedral virus (STIV), an archaeal virus that infects the hyperthermoacidophile Sulfolobus solfataricus, is one of the most well-studied viruses of the domain Archaea. STIV shares structural, morphological, and sequence similarities with viruses from other domains of life, all of which are thought to belong to the same viral lineage. Several of these common features include a conserved coat protein fold, an internal lipid membrane, and a DNA-packaging ATPase. B204 is the ATPase encoded by STIV and is thought to drive packaging of viral DNA during the replication process. Here, we report the crystal structure of B204 along with the biochemical analysis of B204 mutants chosen based on structural information and sequence conservation patterns observed among members of the same viral lineage and the larger FtsK/HerA superfamily to which B204 belongs. Both in vitro ATPase activity assays and transfection assays with mutant forms of B204 confirmed the essentiality of conserved and nonconserved positions. We also have identified two distinct particle morphologies during an STIV infection that differ in the presence or absence of the B204 protein. The biochemical and structural data presented here are not only informative for the STIV replication process but also can be useful in deciphering DNA-packaging mechanisms for other viruses belonging to this lineage. STIV is a virus that infects a host from the domain Archaea that replicates in high-temperature, acidic environments. While STIV has many unique features, there exist several striking similarities between this virus and others that replicate in different environments and infect a broad range of hosts from Bacteria and Eukarya. Aside from structural features shared by viruses from this lineage, there exists a significant level of sequence similarity between the ATPase genes carried by these different viruses; this gene encodes an enzyme thought to provide energy that drives DNA packaging into

Metallic and antiferromagnetic fixed points from gravity

NASA Astrophysics Data System (ADS)

Paul, Chandrima

2018-06-01

We consider SU(2) × U(1) gauge theory coupled to matter field in adjoints and study RG group flow. We constructed Callan-Symanzik equation and subsequent β functions and study the fixed points. We find there are two fixed points, showing metallic and antiferromagnetic behavior. We have shown that metallic phase develops an instability if certain parametric conditions are satisfied.

Normal aging reduces motor synergies in manual pointing.

PubMed

Verrel, Julius; Lövdén, Martin; Lindenberger, Ulman

2012-01-01

Depending upon its organization, movement variability may reflect poor or flexible control of a motor task. We studied adult age-related differences in the structure of postural variability in manual pointing using the uncontrolled manifold (UCM) method. Participants from 2 age groups (younger: 20-30 years; older: 70-80 years; 12 subjects per group) completed a total of 120 pointing trials to 2 different targets presented according to 3 schedules: blocked, alternating, and random. The age groups were similar with respect to basic kinematic variables, end point precision, as well as the accuracy of the biomechanical forward model of the arm. Following the uncontrolled manifold approach, goal-equivalent and nongoal-equivalent components of postural variability (goal-equivalent variability [GEV] and nongoal-equivalent variability [NGEV]) were determined for 5 time points of the movements (start, 10%, 50%, 90%, and end) and used to define a synergy index reflecting the flexibility/stability aspect of motor synergies. Toward the end of the movement, younger adults showed higher synergy indexes than older adults. Effects of target schedule were not reliable. We conclude that normal aging alters the organization of common multidegree-of-freedom movements, with older adults making less flexible use of motor abundance than younger adults. Copyright © 2012 Elsevier Inc. All rights reserved.

Tachyonic instability of the scalar mode prior to the QCD critical point based on the functional renormalization-group method in the two-flavor case

NASA Astrophysics Data System (ADS)

Yokota, Takeru; Kunihiro, Teiji; Morita, Kenji

2017-10-01

We establish and elucidate the physical meaning of the appearance of an acausal mode in the sigma mesonic channel, found in the previous work by the present authors, when the system approaches the Z2 critical point. The functional renormalization-group method is applied to the two-flavor quark-meson model with varying current quark mass mq even away from the physical value at which the pion mass is reproduced. We first determine the whole phase structure in the three-dimensional space (T ,μ ,mq) consisting of temperature T , quark chemical potential μ and mq, with the tricritical point, O(4) and Z2 critical lines being located; they altogether make a winglike shape quite reminiscent of those known in the condensed matters with a tricritical point. We then calculate the spectral functions ρσ ,π(ω ,p ) in the scalar and pseudoscalar channel around the critical points. We find that the sigma mesonic mode becomes tachyonic with a superluminal velocity at finite momenta before the system reaches the Z2 point from the lower density, even for mq smaller than the physical value. One of the possible implications of the appearance of such a tachyonic mode at finite momenta is that the assumed equilibrium state with a uniform chiral condensate is unstable toward a state with an inhomogeneous σ condensate. No such anomalous behavior is found in the pseudoscalar channel. We find that the σ -to-2 σ coupling due to finite mq plays an essential role for the drastic modification of the spectral function.

The quantum structure of anionic hydrogen clusters

NASA Astrophysics Data System (ADS)

Calvo, F.; Yurtsever, E.

2018-03-01

A flexible and polarizable interatomic potential has been developed to model hydrogen clusters interacting with one hydrogen anion, (H2)nH-, in a broad range of sizes n = 1-54 and parametrized against coupled cluster quantum chemical calculations. Using path-integral molecular dynamics simulations at 1 K initiated from the putative classical global minima, the equilibrium structures are found to generally rely on icosahedral shells with the hydrogen molecules pointing toward the anion, producing geometric magic numbers at sizes n = 12, 32, and 44 that are in agreement with recent mass spectrometry measurements. The energetic stability of the clusters is also connected with the extent of vibrational delocalization, measured here by the fluctuations among inherent structures hidden in the vibrational wave function. As the clusters grow, the outer molecules become increasingly free to rotate, and strong finite size effects are also found between magic numbers, associated with more prominent vibrational delocalization. The effective icosahedral structure of the 44-molecule cluster is found to originate from quantum nuclear effects as well, the classical structure showing no particular symmetry.

Symbols on Formal Groups

NASA Astrophysics Data System (ADS)

Vostokov, S. V.

1982-04-01

The theory of a continuous Steinberg symbol in a local field is generalized to formal commutative groups. For Lubin-Tate groups, a universal symbol is constructed in explicit form, and it is shown that the module of values of an arbitrary symbol imbeds into the group of points of the formal group. By means of this theory of symbols a new approach is given to obtaining an explicit form for the Hilbert norm residue symbol on Lubin-Tate formal groups. Bibliography: 10 titles.

Randomised clinical trial of five ear acupuncture points for the treatment of overweight people.

PubMed

Yeo, Sujung; Kim, Kang Sik; Lim, Sabina

2014-04-01

To evaluate the efficacy of the five ear acupuncture points (Shen-men, Spleen, Stomach, Hunger, Endocrine), generally used in Korean clinics for treating obesity, and compare them with the Hunger acupuncture point. A randomised controlled clinical trial was conducted in 91 Koreans (16 male and 75 female, body mass index (BMI)≥23), who had not received any other weight control treatment within the past 6 months. Subjects were divided randomly into treatment I, treatment II or sham control groups and received unilateral auricular acupuncture with indwelling needles replaced weekly for 8 weeks. Treatment I group received acupuncture at the five ear acupuncture points, treatment II group at the Hunger acupuncture point only and the sham control group received acupuncture at the five ear acupuncture points used in treatment I, but the needles were removed immediately after insertion. BMI, waist circumference, weight, body fat mass (BFM), percentage body fat and blood pressure were measured at baseline and at 4 and 8 weeks after treatment. For the 58 participants who provided data at 8 weeks, significant differences in BMI, weight and BFM were found between the treatment and control groups. Treatment groups I and II showed 6.1% and 5.7% reduction in BMI, respectively (p<0.004). There were no significant differences between the two treatment groups. This finding suggests that the five ear acupuncture points, generally used in Korean clinics, and the Hunger point alone treatment are both effective for treating overweight people.

A Chandra-Swift View of Point Sources in Hickson Compact Groups: High AGN Fraction but a Dearth of Strong AGNs

NASA Astrophysics Data System (ADS)

Tzanavaris, P.; Gallagher, S. C.; Hornschemeier, A. E.; Fedotov, K.; Eracleous, M.; Brandt, W. N.; Desjardins, T. D.; Charlton, J. C.; Gronwall, C.

2014-05-01

We present Chandra X-ray point source catalogs for 9 Hickson Compact Groups (HCGs, 37 galaxies) at distances of 34-89 Mpc. We perform detailed X-ray point source detection and photometry and interpret the point source population by means of simulated hardness ratios. We thus estimate X-ray luminosities (LX ) for all sources, most of which are too weak for reliable spectral fitting. For all sources, we provide catalogs with counts, count rates, power-law indices (Γ), hardness ratios, and LX , in the full (0.5-8.0 keV), soft (0.5-2.0 keV), and hard (2.0-8.0 keV) bands. We use optical emission-line ratios from the literature to re-classify 24 galaxies as star-forming, accreting onto a supermassive black hole (AGNs), transition objects, or low-ionization nuclear emission regions. Two-thirds of our galaxies have nuclear X-ray sources with Swift/UVOT counterparts. Two nuclei have L X, 0.5-8.0 keV >1042 erg s-1, are strong multi-wavelength active galactic nuclei (AGNs), and follow the known αOX-νL ν (nearUV) correlation for strong AGNs. Otherwise, most nuclei are X-ray faint, consistent with either a low-luminosity AGN or a nuclear X-ray binary population, and fall in the "non-AGN locus" in αOX-νL ν (nearUV) space, which also hosts other normal galaxies. Our results suggest that HCG X-ray nuclei in high specific star formation rate spiral galaxies are likely dominated by star formation, while those with low specific star formation rates in earlier types likely harbor a weak AGN. The AGN fraction in HCG galaxies with MR <= -20 and L X, 0.5-8.0 keV >=1041 erg s-1 is 0.08^{+0.35}_{-0.01}, somewhat higher than the ~5% fraction in galaxy clusters.

Talking Points: Discussion Activities in the Primary Classroom

ERIC Educational Resources Information Center

Dawes, Lyn

2011-01-01

"Talking Points: Discussion Activities in the Primary Classroom" encourages and supports classroom discussion on a range of topics, enabling children to develop the important life-skill of effective group communication. Children who can explain their own ideas and take account of the points of view and reasons of others are in the process of…

Effects of hydrogen bond on the melting point of azole explosives

NASA Astrophysics Data System (ADS)

Wang, Jian-Hua; Shen, Chen; Liu, Yu-Cun; Luo, Jin; Duan, Yingjie

2018-07-01

Melting point is an important index to determine whether an explosive can be a melt cast carrier. In this study, the relationship among the molecular structure, crystal structure, and melting point of explosives was investigated by using nitroazole compounds. Hydrogen bonds influence crystal packing modes in chemically understandable ways. Hydrogen bonds also affect the changes in entropy and enthalpy in balancing melting process. Hence, different types of hydrogen bonds in explosive crystal structures were compared when the relationship between the molecular structure and the melting point of nitroazole explosives were analyzed. The effects of methyl and amino groups on intermolecular hydrogen bonds were also compared. Results revealed that the methyl and amino groups connected on the N(1) of the heterocyclic compound can reduce the melting point of azole explosive. This finding is possible because methyl and amino groups destroy the intermolecular hydrogen bond of the heterocyclic compound.

Gravity Duals of Lifshitz-Like Fixed Points

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kachru, Shamit; /Stanford U., Phys. Dept. /SLAC; Liu, Xiao

2008-11-05

We find candidate macroscopic gravity duals for scale-invariant but non-Lorentz invariant fixed points, which do not have particle number as a conserved quantity. We compute two-point correlation functions which exhibit novel behavior relative to their AdS counterparts, and find holographic renormalization group flows to conformal field theories. Our theories are characterized by a dynamical critical exponent z, which governs the anisotropy between spatial and temporal scaling t {yields} {lambda}{sup z}t, x {yields} {lambda}x; we focus on the case with z = 2. Such theories describe multicritical points in certain magnetic materials and liquid crystals, and have been shown to arisemore » at quantum critical points in toy models of the cuprate superconductors. This work can be considered a small step towards making useful dual descriptions of such critical points.« less

Design and End Points of Clinical Trials for Patients With Progressive Prostate Cancer and Castrate Levels of Testosterone: Recommendations of the Prostate Cancer Clinical Trials Working Group

PubMed Central

Scher, Howard I.; Halabi, Susan; Tannock, Ian; Morris, Michael; Sternberg, Cora N.; Carducci, Michael A.; Eisenberger, Mario A.; Higano, Celestia; Bubley, Glenn J.; Dreicer, Robert; Petrylak, Daniel; Kantoff, Philip; Basch, Ethan; Kelly, William Kevin; Figg, William D.; Small, Eric J.; Beer, Tomasz M.; Wilding, George; Martin, Alison; Hussain, Maha

2014-01-01

Purpose To update eligibility and outcome measures in trials that evaluate systemic treatment for patients with progressive prostate cancer and castrate levels of testosterone. Methods A committee of investigators experienced in conducting trials for prostate cancer defined new consensus criteria by reviewing previous criteria, Response Evaluation Criteria in Solid Tumors (RECIST), and emerging trial data. Results The Prostate Cancer Clinical Trials Working Group (PCWG2) recommends a two-objective paradigm: (1) controlling, relieving, or eliminating disease manifestations that are present when treatment is initiated and (2) preventing or delaying disease manifestations expected to occur. Prostate cancers progressing despite castrate levels of testosterone are considered castration resistant and not hormone refractory. Eligibility is defined using standard disease assessments to authenticate disease progression, prior treatment, distinct clinical subtypes, and predictive models. Outcomes are reported independently for prostate-specific antigen (PSA), imaging, and clinical measures, avoiding grouped categorizations such as complete or partial response. In most trials, early changes in PSA and/or pain are not acted on without other evidence of disease progression, and treatment should be continued for at least 12 weeks to ensure adequate drug exposure. Bone scans are reported as “new lesions” or “no new lesions,” changes in soft-tissue disease assessed by RECIST, and pain using validated scales. Defining eligibility for prevent/delay end points requires attention to estimated event frequency and/or random assignment to a control group. Conclusion PCWG2 recommends increasing emphasis on time-to-event end points (ie, failure to progress) as decision aids in proceeding from phase II to phase III trials. Recommendations will evolve as data are generated on the utility of intermediate end points to predict clinical benefit. PMID:18309951

The serpentine optical waveguide: engineering the dispersion relations and the stopped light points.

PubMed

Scheuer, Jacob; Weiss, Ori

2011-06-06

We present a study a new type of optical slow-light structure comprising a serpentine shaped waveguide were the loops are coupled. The dispersion relation, group velocity and GVD are studied analytically using a transfer matrix method and numerically using finite difference time domain simulations. The structure exhibits zero group velocity points at the ends of the Brillouin zone, but also within the zone. The position of mid-zone zero group velocity point can be tuned by modifying the coupling coefficient between adjacent loops. Closed-form analytic expressions for the dispersion relations, group velocity and the mid-zone zero v(g) points are found and presented.

[Sacroiliac joint injury treated with oblique insertion at anatomical points: a randomized controlled trial].

PubMed

Kuang, Jiayi; Li, Yuxuan; He, Yufeng; Gan, Lin; Wang, Aiming; Chen, Yanhua; Li, Xiaoting; Guo, Lin; Tang, Rongjun

2016-04-01

To compare the effects of oblique insertion at anatomical points and conventional acupuncture for sacroiliac joint injury. Eighty patients were randomly divided into an observation group and a control group, 40 cases in each one. In the observation group, oblique insertion therapy at anatomical points was used, and the 9 points of equal division (anatomical points) marked by palpating the anatomical symbol were treated as the insertion acupoints. In the control group, conventional acupuncture was applied, and perpendicular insertion was adopted at Huantiao (GB 30), Zhibian (BL 54) and Weizhong (BL 40), etc. In the two groups, the! treatment was given once a day and 5 times per week. Ten treatments were made into one course and two courses were required. The clinical effects, the changes of visual analogue scale (VAS) and Oswestry dysfunctional index. (ODI) before and after treatment were observed in the two groups. The total effective rate of the observation group was 90.0% (36/40), which was better than 72.5% (29/40) of the control group (P < 0.05). After treatment, the results of the VAS and ODI of the two groups were apparently declined (both P < 0.01), and those in the observation group were decreased more obviously (both P < 0.01). The effect of oblique inser-tion at anatomical points for sacroiliac joint injury is superior to that of conventional acupuncture, which can effectively relieve pain and improve the disfunction.

ArtBreak Group Counseling for Children: Framework, Practice Points, and Results

ERIC Educational Resources Information Center

Ziff, Katherine; Ivers, Nathaniel N.; Shaw, Edward G.

2016-01-01

Child social/emotional development and mitigation of child stress are receiving continued emphasis in the literature. While choice-based group art studios have a long association with mental health, documentation on their potential for supporting children is limited. This article describes an elementary school counseling intervention designed to…

Analysis of boron carbides' electronic structure

NASA Technical Reports Server (NTRS)

Howard, Iris A.; Beckel, Charles L.

1986-01-01

The electronic properties of boron-rich icosahedral clusters were studied as a means of understanding the electronic structure of the icosahedral borides such as boron carbide. A lower bound was estimated on bipolaron formation energies in B12 and B11C icosahedra, and the associated distortions. While the magnitude of the distortion associated with bipolaron formation is similar in both cases, the calculated formation energies differ greatly, formation being much more favorable on B11C icosahedra. The stable positions of a divalent atom relative to an icosahedral borane was also investigated, with the result that a stable energy minimum was found when the atom is at the center of the borane, internal to the B12 cage. If incorporation of dopant atoms into B12 cages in icosahedral boride solids is feasible, novel materials might result. In addition, the normal modes of a B12H12 cluster, of the C2B10 cage in para-carborane, and of a B12 icosahedron of reduced (D sub 3d) symmetry, such as is found in the icosahedral borides, were calculated. The nature of these vibrational modes will be important in determining, for instance, the character of the electron-lattice coupling in the borides, and in analyzing the lattice contribution to the thermal conductivity.

Branch-point energies and the band-structure lineup at Schottky contacts and heterostrucures

NASA Astrophysics Data System (ADS)

Mönch, Winfried

2011-06-01

Empirical branch-point energies of Si, the group-III nitrides AlN, GaN, and InN, and the group-II and group-III oxides MgO, ZnO, Al2O3 and In2O3 are determined from experimental valance-band offsets of their heterostructures. For Si, GaN, and MgO, these values agree with the branch-point energies obtained from the barrier heights of their Schottky contacts. The empirical branch-point energies of Si and the group-III nitrides are in very good agreement with results of previously published calculations using quite different approaches such as the empirical tight-binding approximation and modern electronic-structure theory. In contrast, the empirical branch-point energies of the group-II and group-III oxides do not confirm the respective theoretical results. As at Schottky contacts, the band-structure lineup at heterostructures is also made up of a zero-charge-transfer term and an intrinsic electric-dipole contribution. Hence, valence-band offsets are not equal to the difference of the branch-point energies of the two semiconductors forming the heterostructure. The electric-dipole term may be described by the electronegativity difference of the two solids in contact. A detailed analysis of experimental Si Schottky barrier heights and heterostructure valence-band offsets explains and proves these conclusions.

The effect of trigger point management by positional release therapy on tension type headache.

PubMed

Ghanbari, Ali; Rahimijaberi, Abbas; Mohamadi, Marzieh; Abbasi, Leila; Sarvestani, Fahimeh Kamali

2012-01-01

The aim of this study was to compare the effectiveness of trigger points' management by Positional Release Therapy (PRT) and routine medical therapy in treatment of Tension Type Headache. Tension Type Headache is the most frequent headache with the basis of myofascial and trigger point disorders. PRT is an indirect technique that treats trigger points. 30 Patients with active trigger points in cervical muscles entered to the study. They were randomly assigned to PRT or medical therapy group. Headache frequency, intensity and duration and tablet count were recorded by use of a daily headache diary. Sensitivity of trigger points was assessed by numeric pain intensity and by use of a digital force gauge (FG 5020). Both groups showed significant reduction in headache frequency and duration and tablet count after treatment phase. However, the reduction of study variables was persisted only in PRT group after follow up phase. There was no significant reduction in headache intensity, neither in PRT and nor in medication group. Sensitivity of trigger points was significantly reduced. In comparison of the two study groups, there was no significant difference in headache frequency, intensity, duration and tablet count (p> 0.05). Both procedures were equally effective according to the study. Thus, PRT can be a treatment choice for patients with T.T.H.

Group Selection Methods and Contribution to the West Point Leadership Development System (WPLDS)

DTIC Science & Technology

2015-08-01

Government. 14. ABSTRACT Group work in an academic setting can consist of projects or problems students can work on collaboratively. Although pedagogical ...ABSTRACT Group work in an academic setting can consist of projects or problems students can work on collaboratively. Although pedagogical studies...helping students develop intangibles like communication, time management, organization, leadership, interpersonal, and relationship skills. Supporting

Addressing Point of Need in Interactive Multimedia Instruction: A Conceptual Review and Evaluation

DTIC Science & Technology

2013-11-01

classroom setting, ability grouping refers to the practice of putting students into groups on the basis of individual group members’ ability levels...presentation of elaborated/basic vs. advanced material, color cuing, pretesting and modifying learning presentation based on performance) ...learners’ points of need. The point of need concept is focused both on the accessibility of information to support the learning process as well as

Pivots for pointing: visually-monitored pointing has higher arm elevations than pointing blindfolded.

PubMed

Wnuczko, Marta; Kennedy, John M

2011-10-01

Observers pointing to a target viewed directly may elevate their fingertip close to the line of sight. However, pointing blindfolded, after viewing the target, they may pivot lower, from the shoulder, aligning the arm with the target as if reaching to the target. Indeed, in Experiment 1 participants elevated their arms more in visually monitored than blindfolded pointing. In Experiment 2, pointing to a visible target they elevated a short pointer more than a long one, raising its tip to the line of sight. In Experiment 3, the Experimenter aligned the participant's arm with the target. Participants judged they were pointing below a visually monitored target. In Experiment 4, participants viewing another person pointing, eyes-open or eyes-closed, judged the target was aligned with the pointing arm. In Experiment 5, participants viewed their arm and the target via a mirror and posed their arm so that it was aligned with the target. Arm elevation was higher in pointing directly.

Rhinogenic Contact Point Headache: Surgical Treatment Versus Medical Treatment.

PubMed

La Mantia, Ignazio; Grillo, Calogero; Andaloro, Claudio

2018-05-01

Rhinogenic contact point headache (RCPH) is a headache syndrome secondary to mucosal contact points in the sinonasal cavities, in the absence of inflammatory signs, hyperplastic mucosa, purulent discharge, sinonasal polyps, or masses. It may result from pressure on the nasal mucosa due to anatomic variations among which the septal deviation, septal spur, and concha bullosa, are the most commonly observed. In recent years, RCPH has remained a subject of controversy regarding both its pathogenesis and treatment. This study aimed to investigate the effect of surgical and medical treatment of pain relief in patients with RCPH, evaluating the intensity, duration, and frequency of headaches, and the impact of different treatments on quality of life. Ninety-four patients with headache, no symptoms or signs of acute and chronic sinonasal inflammation and who present with intranasal mucosal contact points positive to the lidocaine test were randomized into 2 equal groups and given medical or surgical treatment. The authors used visual analog scale, number of hours, and days with pain to characterize the headache and Migraine Disability Assessment score (MIDAS) to assess the migraine disability score before and 3 to 6 months after treatment. After treatment the severity, duration, and frequency of the headache decreased significantly (P < 0.001, P < 0.001, and P = 0.031, respectively) as well as the MIDAS in the surgical group compared with medical group. Our results suggest that surgical removal of mucosal contact points is more effective than local medical treatment improving the therapeutic outcomes in patients with contact point headache.

A Chandra-Swift View of Point Sources in Hickson Compact Groups: High AGN Fraction but a Dearth of Strong AGNs

NASA Technical Reports Server (NTRS)

Tzanavaris, P.; Gallagher, S. C.; Hornschemeier, A. E.; Fedotov, K.; Eracleous, M.; Brandt, W. N.; Desjardins, T. D.; Charlton, J. C.; Gronwall, C.

2014-01-01

We present Chandra X-ray point source catalogs for 9 Hickson Compact Groups (HCGs, 37 galaxies) at distances of 34-89 Mpc. We perform detailed X-ray point source detection and photometry and interpret the point source population by means of simulated hardness ratios. We thus estimate X-ray luminosities (L(sub x)) for all sources, most of which are too weak for reliable spectral fitting. For all sources, we provide catalogs with counts, count rates, power-law indices (gamma), hardness ratios, and L(sub X), in the full (0.5-8.0 keV), soft (0.5-2.0 keV), and hard (2.0-8.0 keV) bands. We use optical emission-line ratios from the literature to re-classify 24 galaxies as star-forming, accreting onto a supermassive black hole (AGNs), transition objects, or low-ionization nuclear emission regions. Two-thirds of our galaxies have nuclear X-ray sources with Swift/UVOT counterparts. Two nuclei have L(sub X),0.5-8.0 keV > 10(exp 42) erg s-1, are strong multi-wavelength active galactic nuclei (AGNs), and follow the known alpha OX-?L? (nearUV) correlation for strong AGNs. Otherwise, most nuclei are X-ray faint, consistent with either a low-luminosity AGN or a nuclear X-ray binary population, and fall in the 'non-AGN locus' in alpha OX-?L? (nearUV) space, which also hosts other normal galaxies. Our results suggest that HCG X-ray nuclei in high specific star formation rate spiral galaxies are likely dominated by star formation, while those with low specific star formation rates in earlier types likely harbor a weak AGN. The AGN fraction in HCG galaxies with MR (is) less than -20 and L(sub X),0.5-8.0 keV (is) greater than 10(exp 41) erg s-1 is 0.08+0.35 -0.01, somewhat higher than the 5% fraction in galaxy clusters.

A New Approach to Group Learning

ERIC Educational Resources Information Center

Parsons, Jerry

1976-01-01

To help teachers plan strategy for working with a learning group, 12 factors affecting a learning group are discussed and a series of check points are identified as criteria for evaluation. Concepts and principles of group dynamics are drawn from sociology and the work of Carl Rogers. (Author/AJ)

Active Learning: A PowerPoint Tutorial

ERIC Educational Resources Information Center

Gareis, Elisabeth

2007-01-01

Individual or group presentations are common assignments in business communication courses, and many students use PowerPoint slides as audiovisual support. Frequently, curriculum constraints don't allow instructors much time to teach effective design and delivery of presentation graphics in their courses; guidelines in the form of minilectures or…

Internal Medicine Point-of-Care Ultrasound Curriculum: Consensus Recommendations from the Canadian Internal Medicine Ultrasound (CIMUS) Group.

PubMed

Ma, Irene W Y; Arishenkoff, Shane; Wiseman, Jeffrey; Desy, Janeve; Ailon, Jonathan; Martin, Leslie; Otremba, Mirek; Halman, Samantha; Willemot, Patrick; Blouw, Marcus

2017-09-01

Bedside point-of-care ultrasound (POCUS) is increasingly used to assess medical patients. At present, no consensus exists for what POCUS curriculum is appropriate for internal medicine residency training programs. This document details the consensus-based recommendations by the Canadian Internal Medicine Ultrasound (CIMUS) group, comprising 39 members, representing 14 institutions across Canada. Guiding principles for selecting curricular content were determined a priori. Consensus was defined as agreement by at least 80% of the members on POCUS applications deemed appropriate for teaching and assessment of trainees in the core (internal medicine postgraduate years [PGY] 1-3) and expanded (general internal medicine PGY 4-5) training programs. We recommend four POCUS applications for the core PGY 1-3 curriculum (inferior vena cava, lung B lines, pleural effusion, and abdominal free fluid) and three ultrasound-guided procedures (central venous catheterization, thoracentesis, and paracentesis). For the expanded PGY 4-5 curriculum, we recommend an additional seven applications (internal jugular vein, lung consolidation, pneumothorax, knee effusion, gross left ventricular systolic function, pericardial effusion, and right ventricular strain) and four ultrasound-guided procedures (knee arthrocentesis, arterial line insertion, arterial blood gas sampling, and peripheral venous catheterization). These recommendations will provide a framework for training programs at a national level.

MS Power Point vs Prezi in Higher Education

ERIC Educational Resources Information Center

Kiss, Gabor

2016-01-01

The teachers use different presentation tools in Higher Education to make the presentation enjoyable for the students. I used MS Power Point or Prezi in my presentations in two different groups of the freshmen students at the University. The aim of this research was an analysis of the paper results in two groups of students to reveal the influence…

Estimating the physicochemical properties of polyhalogenated aromatic and aliphatic compounds using UPPER: part 1. Boiling point and melting point.

PubMed

Admire, Brittany; Lian, Bo; Yalkowsky, Samuel H

2015-01-01

The UPPER (Unified Physicochemical Property Estimation Relationships) model uses enthalpic and entropic parameters to estimate 20 biologically relevant properties of organic compounds. The model has been validated by Lian and Yalkowsky on a data set of 700 hydrocarbons. The aim of this work is to expand the UPPER model to estimate the boiling and melting points of polyhalogenated compounds. In this work, 19 new group descriptors are defined and used to predict the transition temperatures of an additional 1288 compounds. The boiling points of 808 and the melting points of 742 polyhalogenated compounds are predicted with average absolute errors of 13.56 K and 25.85 K, respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

Students perception on the usage of PowerPoint in learning calculus

NASA Astrophysics Data System (ADS)

Othman, Zarith Sofiah; Tarmuji, Nor Habibah; Hilmi, Zulkifli Ab Ghani

2017-04-01

Mathematics is a core subject in most of the science and technology courses and in some social sciences programs. However, the low achievement of students in the subject especially in topics such as Differentiation and Integration is always an issue. Many factors contribute to the low performance such as motivation, environment, method of learning, academic background and others. The purpose of this paper is to determine the perception of learning mathematics using PowerPoint on Integration concepts at the undergraduate level with respect to mathematics anxiety, learning enjoyment, mobility and learning satisfaction. The main content of the PowerPoint presentation focused on the integration method with historical elements as an added value. The study was conducted on 48 students randomly selected from students in computer and applied sciences program as experimental group. Questionnaires were distributed to students to explore their learning experiences. Another 51 students who were taught using the traditional chalkboard method were used as the control group. Both groups were given a test on Integration. The statistical methods used were descriptive statistics and independent sample t-test between the experimental and the control group. The finding showed that most students perceived positively to the PowerPoint presentations with respect to mobility and learning satisfaction. The experimental group performed better than the control group.

Pointing at targets by children with congenital and transient blindness.

PubMed

Gaunet, Florence; Ittyerah, Miriam; Rossetti, Yves

2007-04-01

The study investigated pointing at memorized targets in reachable space in congenitally blind (CB) and blindfolded sighted (BS) children (6, 8, 10 and 12 years; ten children in each group). The target locations were presented on a sagittal plane by passive positioning of the left index finger. A go signal for matching the target location with the right index finger was provided 0 or 4 s after demonstration. An age effect was found only for absolute distance errors and the surface area of pointing was smaller for the CB children. Results indicate that early visual experience and age are not predictive factors for pointing in children. The delay was an important factor at all ages and for both groups, indicating distinct spatial representations such as egocentric and allocentric frames of reference, for immediate and delayed pointing, respectively. Therefore, the CB like the BS children are able to use both ego- and allocentric frames of reference.

[Clinical observation on auricular point magnetotherapy for treatment of senile low back pain].

PubMed

Sun, Gui-Ping

2007-02-01

To compare the therapeutic effects of auricular point magnetotherapy and auricular point sticking of Vaccaria seed on senile low back pain. Sixty cases, aged 60 or over 60 years with back pain, were randomly divided into 2 groups, a control group and a test group. The control group were treated with auricular sticking of Vaccaria seed with no pressing, and the test group with sticking magnetic bead of 66 gauss each piece with no pressing. Auricular points, Shenmen, Kidney, Bladder, Yaodizhui, Gluteus, Liver and Spleen were selected. Three weeks constituted one course. The effects before, during and after the course were assessed by questionnaire about back pain. Compared with the control group, in the test group the back pain was more effectively improved, including reducing pain and numbness in the back and the legs, decreasing the disorder of physical strength induced by this disease, and improving daily life quality of the patient. Follow-up survey for 2-4 weeks showed the effects still were kept. Auricular magnetotherapy can effectively improve senile back pain.

A scalable and multi-purpose point cloud server (PCS) for easier and faster point cloud data management and processing

NASA Astrophysics Data System (ADS)

Cura, Rémi; Perret, Julien; Paparoditis, Nicolas

2017-05-01

In addition to more traditional geographical data such as images (rasters) and vectors, point cloud data are becoming increasingly available. Such data are appreciated for their precision and true three-Dimensional (3D) nature. However, managing point clouds can be difficult due to scaling problems and specificities of this data type. Several methods exist but are usually fairly specialised and solve only one aspect of the management problem. In this work, we propose a comprehensive and efficient point cloud management system based on a database server that works on groups of points (patches) rather than individual points. This system is specifically designed to cover the basic needs of point cloud users: fast loading, compressed storage, powerful patch and point filtering, easy data access and exporting, and integrated processing. Moreover, the proposed system fully integrates metadata (like sensor position) and can conjointly use point clouds with other geospatial data, such as images, vectors, topology and other point clouds. Point cloud (parallel) processing can be done in-base with fast prototyping capabilities. Lastly, the system is built on open source technologies; therefore it can be easily extended and customised. We test the proposed system with several billion points obtained from Lidar (aerial and terrestrial) and stereo-vision. We demonstrate loading speeds in the ˜50 million pts/h per process range, transparent-for-user and greater than 2 to 4:1 compression ratio, patch filtering in the 0.1 to 1 s range, and output in the 0.1 million pts/s per process range, along with classical processing methods, such as object detection.

Csf Based Non-Ground Points Extraction from LIDAR Data

NASA Astrophysics Data System (ADS)

Shen, A.; Zhang, W.; Shi, H.

2017-09-01

Region growing is a classical method of point cloud segmentation. Based on the idea of collecting the pixels with similar properties to form regions, region growing is widely used in many fields such as medicine, forestry and remote sensing. In this algorithm, there are two core problems. One is the selection of seed points, the other is the setting of the growth constraints, in which the selection of the seed points is the foundation. In this paper, we propose a CSF (Cloth Simulation Filtering) based method to extract the non-ground seed points effectively. The experiments have shown that this method can obtain a group of seed spots compared with the traditional methods. It is a new attempt to extract seed points

Special Interest Groups.

ERIC Educational Resources Information Center

Degi, Bruce J.

1999-01-01

Offers a reflection on the shootings at Columbine High School in Littleton, Colorado, on April 20, 1999. Notes how every special-interest group has used the tragedy to support its own point of view, and concludes that teachers have become bystanders in the education of America's children. (SR)

Teaching Structure-Property Relationships: Investigating Molecular Structure and Boiling Point

ERIC Educational Resources Information Center

Murphy, Peter M.

2007-01-01

A concise, well-organized table of the boiling points of 392 organic compounds has facilitated inquiry-based instruction in multiple scientific principles. Many individual or group learning activities can be derived from the tabulated data of molecular structure and boiling point based on the instructor's education objectives and the students'…

A dye-assisted paper-based point-of-care assay for fast and reliable blood grouping.

PubMed

Zhang, Hong; Qiu, Xiaopei; Zou, Yurui; Ye, Yanyao; Qi, Chao; Zou, Lingyun; Yang, Xiang; Yang, Ke; Zhu, Yuanfeng; Yang, Yongjun; Zhou, Yang; Luo, Yang

2017-03-15

Fast and simultaneous forward and reverse blood grouping has long remained elusive. Forward blood grouping detects antigens on red blood cells, whereas reverse grouping identifies specific antibodies present in plasma. We developed a paper-based assay using immobilized antibodies and bromocresol green dye for rapid and reliable blood grouping, where dye-assisted color changes corresponding to distinct blood components provide a visual readout. ABO antigens and five major Rhesus antigens could be detected within 30 s, and simultaneous forward and reverse ABO blood grouping using small volumes (100 μl) of whole blood was achieved within 2 min through on-chip plasma separation without centrifugation. A machine-learning method was developed to classify the spectral plots corresponding to dye-based color changes, which enabled reproducible automatic grouping. Using optimized operating parameters, the dye-assisted paper assay exhibited comparable accuracy and reproducibility to the classical gel-card assays in grouping 3550 human blood samples. When translated to the assembly line and low-cost manufacturing, the proposed approach may be developed into a cost-effective and robust universal blood-grouping platform. Copyright © 2017, American Association for the Advancement of Science.

78 FR 8588 - Rg Steel Sparrows Point LLC, Formerly Known as Severstal Sparrows Point LLC, a Subsidiary of RG...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-06

..., Alliance Engineering, Inc., Washington Group International, Javan & Walter, Inc., Kinetic Technical... Consulting, Crown Security, Eastern Automation, EDS(HP), Teksystems, URS Corporation, and B More Industrial... from B More Industrial Services LLC were employed on-site at the Sparrows Point, Maryland location of...

Context-dependent arm pointing adaptation

NASA Technical Reports Server (NTRS)

Seidler, R. D.; Bloomberg, J. J.; Stelmach, G. E.

2001-01-01

We sought to determine the effectiveness of head posture as a contextual cue to facilitate adaptive transitions in manual control during visuomotor distortions. Subjects performed arm pointing movements by drawing on a digitizing tablet, with targets and movement trajectories displayed in real time on a computer monitor. Adaptation was induced by presenting the trajectories in an altered gain format on the monitor. The subjects were shown visual displays of their movements that corresponded to either 0.5 or 1.5 scaling of the movements made. Subjects were assigned to three groups: the head orientation group tilted the head towards the right shoulder when drawing under a 0.5 gain of display and towards the left shoulder when drawing under a 1.5 gain of display; the target orientation group had the home and target positions rotated counterclockwise when drawing under the 0.5 gain and clockwise for the 1.5 gain; the arm posture group changed the elbow angle of the arm they were not drawing with from full flexion to full extension with 0.5 and 1.5 gain display changes. To determine if contextual cues were associated with display alternations, the gain changes were returned to the standard (1.0) display. Aftereffects were assessed to determine the efficacy of the head orientation contextual cue compared to the two control cues. The head orientation cue was effectively associated with the multiple gains. The target orientation cue also demonstrated some effectiveness while the arm posture cue did not. The results demonstrate that contextual cues can be used to switch between multiple adaptive states. These data provide support for the idea that static head orientation information is a crucial component to the arm adaptation process. These data further define the functional linkage between head posture and arm pointing movements.

Context-Dependent Arm Pointing Adaptation

NASA Technical Reports Server (NTRS)

Seidler, R. D.; Bloomberg, J. J.; Stelmach, G. E.

2000-01-01

We sought to determine the effectiveness of head posture as a contextual cue to facilitate adaptive transitions in manual control during visuomotor distortions. Subjects performed arm pointing movements by drawing on a digitizing tablet, with targets and movement trajectories displayed in real time on a computer monitor. Adaptation was induced by presenting the trajectories in an altered gain format on the monitor. The subjects were shown visual displays of their movements that corresponded to either 0.5 or 1.5 scaling of the movements made. Subjects were assigned to three groups: the head orientation group tilted the head towards the right shoulder when drawing under a 0.5 gain of display and towards the left shoulder when drawing under a 1.5 gain of display, the target orientation group had the home & target positions rotated counterclockwise when drawing under the 0.5 gain and clockwise for the 1.5 gain, the arm posture group changed the elbow angle of the arm they were not drawing with from full flexion to full extension with 0.5 and 1.5 gain display changes. To determine if contextual cues were associated with display alternations, the gain changes were returned to the standard (1.0) display. Aftereffects were assessed to determine the efficacy of the head orientation contextual cue. . compared to the two control cues. The head orientation cue was effectively associated with the multiple gains. The target orientation cue also demonstrated some effectiveness while the.arm posture cue did not. The results demonstrate that contextual cues can be used to switch between multiple adaptive states. These data provide support for the idea that static head orientation information is a crucial component to the arm adaptation process. These data further define the functional linkage between head posture and arm pointing movements.

Comparison of shoulder strength in males with and without myofascial trigger points in the upper trapezius.

PubMed

Kim, H A; Hwang, U J; Jung, S H; Ahn, S H; Kim, J H; Kwon, O Y

2017-11-01

This study was conducted in order to compare the strength of scapular elevator and shoulder abductor with and without restricted scapular elevation between male subjects with and without myofascial trigger points in the upper trapezius. In total, 15 male subjects with myofascial trigger points, and 15age- and weight-matched male subjects without myofascial trigger points in the upper trapezius. Each subject was measured in the strength of maximum isometric scapular elevation and shoulder abduction with and without restricted scapular elevation. Maximum isometric contractions were measured using the Smart KEMA strength measurement system. Independent t-tests were used to compare shoulder strength values between the myofascial trigger points and non- myofascial trigger points groups. The results showed that shoulder abductor strength in the group with myofascial trigger points (5.64kgf) was significantly lower than in the group without myofascial trigger points (11.96kgf) when scapular elevation was restricted (p<0.05). However, there was no significant difference in the strength of the scapular elevator or shoulder abductor between groups (p>0.05). These findings suggest that decreased strength in the shoulder abductor with restricted scapular elevation should be considered in evaluating and treating individuals with myofascial trigger points of the upper trapezius. Copyright © 2017 Elsevier Ltd. All rights reserved.

Girls' Groups and Boys' Groups at a Municipal Technology Centre

ERIC Educational Resources Information Center

Salminen-Karlsson, Minna

2007-01-01

This article describes the Swedish initiative of municipal technology centres from a gender point of view. These centres provide after-school technology education for children aged 6-16. By means of an ethnographic study, the effects of the use of single-sex groups in increasing the interest of girls and boys in technical activities have been…

Absolute Points for Multiple Assignment Problems

ERIC Educational Resources Information Center

Adlakha, V.; Kowalski, K.

2006-01-01

An algorithm is presented to solve multiple assignment problems in which a cost is incurred only when an assignment is made at a given cell. The proposed method recursively searches for single/group absolute points to identify cells that must be loaded in any optimal solution. Unlike other methods, the first solution is the optimal solution. The…

7 CFR 29.1162 - Leaf (B Group).

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 2 2012-01-01 2012-01-01 false Leaf (B Group). 29.1162 Section 29.1162 Agriculture... INSPECTION Standards Grades § 29.1162 Leaf (B Group). This group consists of leaves normally grown at or above the midportion of the stalk. Leaves of the B group have a pointed tip, tend to fold, usually are...

7 CFR 29.1162 - Leaf (B Group).

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 2 2013-01-01 2013-01-01 false Leaf (B Group). 29.1162 Section 29.1162 Agriculture... INSPECTION Standards Grades § 29.1162 Leaf (B Group). This group consists of leaves normally grown at or above the midportion of the stalk. Leaves of the B group have a pointed tip, tend to fold, usually are...

7 CFR 29.1162 - Leaf (B Group).

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 2 2014-01-01 2014-01-01 false Leaf (B Group). 29.1162 Section 29.1162 Agriculture... INSPECTION Standards Grades § 29.1162 Leaf (B Group). This group consists of leaves normally grown at or above the midportion of the stalk. Leaves of the B group have a pointed tip, tend to fold, usually are...

Distinct DNA exit and packaging portals in the virus Acanthamoeba polyphaga mimivirus.

PubMed

Zauberman, Nathan; Mutsafi, Yael; Halevy, Daniel Ben; Shimoni, Eyal; Klein, Eugenia; Xiao, Chuan; Sun, Siyang; Minsky, Abraham

2008-05-13

Icosahedral double-stranded DNA viruses use a single portal for genome delivery and packaging. The extensive structural similarity revealed by such portals in diverse viruses, as well as their invariable positioning at a unique icosahedral vertex, led to the consensus that a particular, highly conserved vertex-portal architecture is essential for viral DNA translocations. Here we present an exception to this paradigm by demonstrating that genome delivery and packaging in the virus Acanthamoeba polyphaga mimivirus occur through two distinct portals. By using high-resolution techniques, including electron tomography and cryo-scanning electron microscopy, we show that Mimivirus genome delivery entails a large-scale conformational change of the capsid, whereby five icosahedral faces open up. This opening, which occurs at a unique vertex of the capsid that we coined the "stargate", allows for the formation of a massive membrane conduit through which the viral DNA is released. A transient aperture centered at an icosahedral face distal to the DNA delivery site acts as a non-vertex DNA packaging portal. In conjunction with comparative genomic studies, our observations imply a viral packaging pathway akin to bacterial DNA segregation, which might be shared by diverse internal membrane-containing viruses.

Distinct DNA Exit and Packaging Portals in the Virus Acanthamoeba polyphaga mimivirus

PubMed Central

Zauberman, Nathan; Mutsafi, Yael; Halevy, Daniel Ben; Shimoni, Eyal; Klein, Eugenia; Xiao, Chuan; Sun, Siyang; Minsky, Abraham

2008-01-01

Icosahedral double-stranded DNA viruses use a single portal for genome delivery and packaging. The extensive structural similarity revealed by such portals in diverse viruses, as well as their invariable positioning at a unique icosahedral vertex, led to the consensus that a particular, highly conserved vertex-portal architecture is essential for viral DNA translocations. Here we present an exception to this paradigm by demonstrating that genome delivery and packaging in the virus Acanthamoeba polyphaga mimivirus occur through two distinct portals. By using high-resolution techniques, including electron tomography and cryo-scanning electron microscopy, we show that Mimivirus genome delivery entails a large-scale conformational change of the capsid, whereby five icosahedral faces open up. This opening, which occurs at a unique vertex of the capsid that we coined the “stargate”, allows for the formation of a massive membrane conduit through which the viral DNA is released. A transient aperture centered at an icosahedral face distal to the DNA delivery site acts as a non-vertex DNA packaging portal. In conjunction with comparative genomic studies, our observations imply a viral packaging pathway akin to bacterial DNA segregation, which might be shared by diverse internal membrane–containing viruses. PMID:18479185

Round and pointed-head grenadier fishes (Actinopterygii: Gadiformes) represent a single sister group: evidence from the complete mitochondrial genome sequences.

PubMed

Satoh, Takashi P; Miya, Masaki; Endo, Hiromitsu; Nishida, Mutsumi

2006-07-01

The gene order of mitochondrial genomes (mitogenomes) has been employed as a useful phylogenetic marker in various metazoan animals, because it may represent uniquely derived characters shared by members of monophyletic groups. During the course of molecular phylogenetic studies of the order Gadiformes (cods and their relatives) based on whole mitogenome sequences, we found that two deep-sea grenadiers (Squalogadus modificatus and Trachyrincus murrayi: family Macrouridae) revealed a unusually identical gene order (translocation of the tRNA(Leu (UUR))). Both are members of the same family, although their external morphologies differed so greatly (e.g., round vs. pointed head) that they have been placed in different subfamilies Macrouroidinae and Trachyrincinae, respectively. Additionally, we determined the whole mitogenome sequences of two other species, Bathygadus antrodes and Ventrifossa garmani, representing a total of four subfamilies currently recognized within Macrouridae. The latter two species also exhibited gene rearrangements, resulting in a total of three different patterns of unique gene order being observed in the four subfamilies. Partitioned Bayesian analysis was conducted using available whole mitogenome sequences from five macrourids plus five outgroups. The resultant trees clearly indicated that S. modificatus and T. murrayi formed a monophyletic group, having a sister relationship to other macrourids. Thus, monophyly of the two species with disparate head morphologies was corroborated by two different lines of evidence (nucleotide sequences and gene order). The overall topology of the present tree differed from any of the previously proposed, morphology-based phylogenetic hypotheses.

Using Technology to Unify Geometric Theorems about the Power of a Point

ERIC Educational Resources Information Center

Contreras, Jose N.

2011-01-01

In this article, I describe a classroom investigation in which a group of prospective secondary mathematics teachers discovered theorems related to the power of a point using "The Geometer's Sketchpad" (GSP). The power of a point is defines as follows: Let "P" be a fixed point coplanar with a circle. If line "PA" is a secant line that intersects…

Stress and nurses' horizontal mobbing: moderating effects of group identity and group support.

PubMed

Topa, Gabriela; Moriano, Juan A

2013-01-01

Horizontal mobbing is a process of systematic and repeated aggression towards a worker by coworkers. Among others, stress has been pointed out as one of the antecedents that favors the onset of horizontal mobbing, whereas group support to the target could act as a buffer. Moreover, the social identity approach emphasizes that group identity is an antecedent of group support. This study explores the interaction of group support and group identity in the explanation of horizontal mobbing in a sample (N = 388) of registered nurses and licensed practical nurses employed at two large hospitals in Madrid and Navarre (Spain). The results show that stress is positively associated to horizontal mobbing, whereas group support and group identity were negative predictors of horizontal mobbing. Furthermore, the combination of low group identity and low group support precipitated HM among nurses. Copyright © 2013 Elsevier Inc. All rights reserved.

Non-invasive evaluation of stable renal allograft function using point shear-wave elastography.

PubMed

Kim, Bom Jun; Kim, Chan Kyo; Park, Jung Jae

2018-01-01

To investigate the feasibility of point shear-wave elastography (SWE) in evaluating patients with stable renal allograft function who underwent protocol biopsies. 95 patients with stable renal allograft function that underwent ultrasound-guided biopsies at predefined time points (10 days or 1 year after transplantation) were enrolled. Ultrasound and point SWE examinations were performed immediately before protocol biopsies. Patients were categorized into two groups: subclinical rejection (SCR) and non-SCR. Tissue elasticity (kPa) on SWE was measured in the cortex of all renal allografts. SCR was pathologically confirmed in 34 patients. Tissue elasticity of the SCR group (31.0 kPa) was significantly greater than that of the non-SCR group (24.5 kPa) (=0.016), while resistive index value did not show a significant difference between the two groups (p = 0.112). Tissue elasticity in renal allografts demonstrated significantly moderate negative correlation with estimated glomerular filtration rate (correlation coefficient = -0.604, p < 0.001). Tissue elasticity was not independent factor for SCR prediction on multivariate analysis. As a non-invasive tool, point SWE appears feasible in distinguishing between patients with SCR and without SCR in stable functioning renal allografts. Moreover, it may demonstrate the functional state of renal allografts. Advances in knowledge: On point SWE, SCR has greater tissue elasticity than non-SCR.

Pseudo-point transport technique: a new method for solving the Boltzmann transport equation in media with highly fluctuating cross sections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakhai, B.

A new method for solving radiation transport problems is presented. The heart of the technique is a new cross section processing procedure for the calculation of group-to-point and point-to-group cross sections sets. The method is ideally suited for problems which involve media with highly fluctuating cross sections, where the results of the traditional multigroup calculations are beclouded by the group averaging procedures employed. Extensive computational efforts, which would be required to evaluate double integrals in the multigroup treatment numerically, prohibit iteration to optimize the energy boundaries. On the other hand, use of point-to-point techniques (as in the stochastic technique) ismore » often prohibitively expensive due to the large computer storage requirement. The pseudo-point code is a hybrid of the two aforementioned methods (group-to-group and point-to-point) - hence the name pseudo-point - that reduces the computational efforts of the former and the large core requirements of the latter. The pseudo-point code generates the group-to-point or the point-to-group transfer matrices, and can be coupled with the existing transport codes to calculate pointwise energy-dependent fluxes. This approach yields much more detail than is available from the conventional energy-group treatments. Due to the speed of this code, several iterations could be performed (in affordable computing efforts) to optimize the energy boundaries and the weighting functions. The pseudo-point technique is demonstrated by solving six problems, each depicting a certain aspect of the technique. The results are presented as flux vs energy at various spatial intervals. The sensitivity of the technique to the energy grid and the savings in computational effort are clearly demonstrated.« less

Group as social microcosm: Within-group interpersonal style is congruent with outside group relational tendencies.

PubMed

Goldberg, Simon B; Hoyt, William T

2015-06-01

The notion that individuals' interpersonal behaviors in the context of therapy reflects their interpersonal behaviors outside of therapy is a fundamental hypothesis underlying numerous systems of psychotherapy. The social microcosm hypothesis, in particular, claims the interpersonal therapy group becomes a reflection of group members' general tendencies, and can thus be used as information about members' interpersonal functioning as well as an opportunity for learning and behavior change. The current study tested this hypothesis using data drawn from 207 individuals participating in 22 interpersonal process groups. Ratings were made on 2 key interpersonal domains (Dominance and Affiliation) at baseline and at Weeks 2, 5, and 8 of the group. Two-level multilevel models (with participants nested within groups) were used to account for the hierarchical structure, and the social relations model (SRM; Kenny, 1994) was used to estimate peer ratings (target effects in SRM) unconfounded with rater bias. Participants showed consensus at all time points during the interpersonal process groups on one another's levels of dominance and affiliation. In addition, self- and peer ratings were stable across time and correlated with one another. Importantly, self-ratings made prior to group significantly predicted ratings (self- and peer) made within the group, with effect sizes within the medium range. Taken together, these results provide robust support for the social microcosm hypothesis and the conjecture that interpersonal style within-group therapy is reflective of broader interpersonal tendencies. (c) 2015 APA, all rights reserved).

Unlocking Internal Prestress from Protein Nanoshells

NASA Astrophysics Data System (ADS)

Klug, W. S.; Roos, W. H.; Wuite, G. J. L.

2012-10-01

The capsids of icosahedral viruses are closed shells assembled from a hexagonal lattice of proteins with fivefold angular defects located at the icosahedral vertices. Elasticity theory predicts that these disclinations are subject to an internal compressive prestress, which provides an explanation for the link between size and shape of capsids. Using a combination of experiment and elasticity theory we investigate the question of whether macromolecular assemblies are subject to residual prestress, due to basic geometric incompatibility of the subunits. Here we report the first direct experimental test of the theory: by controlled removal of protein pentamers from the icosahedral vertices, we measure the mechanical response of so-called “whiffle ball” capsids of herpes simplex virus, and demonstrate the signature of internal prestress locked into wild-type capsids during assembly.

Why Are Buckyonions Round?

NASA Technical Reports Server (NTRS)

Bates, Kevin R.; Scuseria, Gustavo E.

1997-01-01

Multi-layered round carbon particles (onions) containing tens to hundreds of thousands of atoms form during electron irradiation of graphite carbon. However, theoretical models of large icosahedral fullerenes predict highly faceted shapes for molecules with more than a few hundred atoms. This discrepancy in shape may be explained by the presence of defects during the formation of carbon onions. Here, we use the semi-empirical tight-binding method for carbon to simulate the incorporation of pentagon-heptagon defects on to the surface of large icosahedral fullerenes. We show a simple mechanism that results in energetically competitive derivative structures and a global change in molecular shape from faceted to round. Our results provide a plausible explanation of the apparent discrepancy between experimental observations of round buckyonions and theoretical predictions of faceted icosahedral fullerenes.

Why are Buckyonions Round?

NASA Technical Reports Server (NTRS)

Bates, Kevin R.; Scuseria, Gustavo E.

1998-01-01

Multi-layered round carbon particles (onions) containing tens to hundreds of thousands of atoms form during electron irradiation of graphite. However. theoretical models or large icosahedral fullerenes predict highly faceted shapes for molecules with more than a few hundred atoms. This discrepancy in shape may be explained by the presence of defects during the formation of carbon onions. Here, we use the semi-empirical tight-binding method for carbon to simulate the incorporation of pentagon-heptagon defects on to the surface of large icosahedral fullerenes. We show a simple mechanism that results in energetically competitive derivative structures and a global change in molecular shape from faceted to round. Our results provide a plausible explanation of the apparent discrepancy between experimental observations or round buckyonions and theoretical predictions of faceted icosahedral fullerenes.

Group Problem Solving.

ERIC Educational Resources Information Center

King, James C.

1988-01-01

This pamphlet discusses group problem solving in schools. Its point of departure is that teachers go at problems from a number of different directions and that principals need to capitalize on those differences and bring a whole range of skills and perceptions to the problem-solving process. Rather than trying to get everyone to think alike,…

The two-point correlation function for groups of galaxies in the Center for Astrophysics redshift survey

NASA Technical Reports Server (NTRS)

Ramella, Massimo; Geller, Margaret J.; Huchra, John P.

1990-01-01

The large-scale distribution of groups of galaxies selected from complete slices of the CfA redshift survey extension is examined. The survey is used to reexamine the contribution of group members to the galaxy correlation function. The relationship between the correlation function for groups and those calculated for rich clusters is discussed, and the results for groups are examined as an extension of the relation between correlation function amplitude and richness. The group correlation function indicates that groups and individual galaxies are equivalent tracers of the large-scale matter distribution. The distribution of group centers is equivalent to random sampling of the galaxy distribution. The amplitude of the correlation function for groups is consistent with an extrapolation of the amplitude-richness relation for clusters. The amplitude scaled by the mean intersystem separation is also consistent with results for richer clusters.

Prognostic grouping of metastatic prostate cancer using conventional pretreatment prognostic factors.

PubMed

Mikkola, Arto; Aro, Jussi; Rannikko, Sakari; Ruutu, Mirja

2009-01-01

To develop three prognostic groups for disease specific mortality based on the binary classified pretreatment variables age, haemoglobin concentration (Hb), erythrocyte sedimentation rate (ESR), alkaline phosphatase (ALP), prostate-specific antigen (PSA), plasma testosterone and estradiol level in hormonally treated patients with metastatic prostate cancer (PCa). The present study comprised 200 Finnprostate 6 study patients, but data on all variables were not known for every patient. The patients were divided into three prognostic risk groups (Rgs) using the prognostically best set of pretreatment variables. The best set was found by backward stepwise selection and the effect of every excluded variable on the binary classification cut-off points of the remaining variables was checked and corrected when needed. The best group of variables was ALP, PSA, ESR and age. All data were known in 142 patients. Patients were given one risk point each for ALP > 180 U/l (normal value 60-275 U/l), PSA > 35 microg/l, ESR > 80 mm/h and age < 60 years. Three risk groups were formed: Rg-a (0-1 risk points), Rg-b (2 risk points) and Rg-c (3-4 risk points). The risk of death from PCa increased statistically significantly with advancing prognostic group. Patients with metastatic PCa can be divided into three statistically significantly different prognostic risk groups for PCa-specific mortality by using the binary classified pretreatment variables ALP, PSA, ESR and age.

The "group" in obstetric psychoprophylaxis.

PubMed

Volpe, B; Tenaglia, F; Fede, T; Cerutti, R

1983-01-01

In the practice of obstetric psychoprophylaxis every method employed considered always the group both from a psychological and a pedagogic point of view. Today the group of pregnant women (or couples) is considered under various aspects: - psychological: the group as a support for members with regard to maternal and parental emotional feelings; - anthropological: the group fills up an empty vital space and becomes a "rite de passage" from a state of social identity to another one; - social: the group is a significative cultural intermediary between health services and the women-patient. The knowledge of these aspects becomes an important methodological support for group conductors. We present an analysis of our experience with groups and how this has affected the Psychoprophylaxis in the last years.

Group choice: the ideal free distribution of human social behavior.

PubMed

Kraft, J R; Baum, W M

2001-07-01

Group choice refers to the distribution of group members between two choice alternatives over time. The ideal free distribution (IFD), an optimal foraging model from behavioral ecology, predicts that the ratio of foragers at two resource sites should equal the ratio of obtained resources, a prediction that is formally analogous to the matching law of individual choice, except that group choice is a social phenomenon. Two experiments investigated the usefulness of IFD analyses of human group choice and individual-based explanations that might account for the group-level events. Instead of nonhuman animals foraging at two sites for resources, a group of humans chose blue and red cards to receive points that could earn cash prizes. The groups chose blue and red cards in ratios in positive relation to the ratios of points associated with the cards. When group choice ratios and point ratios were plotted on logarithmic coordinates and fitted with regression lines, the slopes (i.e., sensitivity measures) approached 1.0 but tended to fall short of it (i.e., undermatching), with little bias and little unaccounted for variance. These experiments demonstrate that an IFD analysis of group choice is possible and useful, and suggest that group choice may be explained by the individual members' tendency to optimize reinforcement.

Contribution of myofascial trigger points to migraine symptoms.

PubMed

Giamberardino, Maria Adele; Tafuri, Emmanuele; Savini, Antonella; Fabrizio, Alessandra; Affaitati, Giannapia; Lerza, Rosanna; Di Ianni, Livio; Lapenna, Domenico; Mezzetti, Andrea

2007-11-01

This study evaluated the contribution of myofascial trigger points (TrPs) to migraine pain. Seventy-eight migraine patients with cervical active TrPs whose referred areas (RAs) coincided with migraine sites (frontal/temporal) underwent electrical pain threshold measurement in skin, subcutis, and muscle in TrPs and RAs at baseline and after 3, 10, 30, and 60 days; migraine pain assessment (number and intensity of attacks) for 60 days before and 60 days after study start. Fifty-four patients (group 1) underwent TrP anesthetic infiltration on the 3rd, 10th, 30th, and 60th day (after threshold measurement); 24 (group 2) received no treatment. Twenty normal subjects underwent threshold measurements in the same sites and time points as patients. At baseline, all patients showed lower than normal thresholds in TrPs and RAs in all tissues (P < .001). During treatment in group 1, all thresholds increased progressively in TrPs and RAs (P < .0001), with sensory normalization of skin/subcutis in RAs at the end of treatment; migraine pain decreased (P < .001). Threshold increase in RAs and migraine reduction correlated linearly (.0001 < P < .006). In group 2 and normal subjects, no changes occurred. Cervical TrPs with referred areas in migraine sites thus contribute substantially to migraine symptoms, the peripheral nociceptive input from TrPs probably enhancing the sensitization level of central sensory neurons. This article shows the beneficial effects of local therapy of active myofascial trigger points (TrPs) on migraine symptoms in patients in whom migraine sites coincide with the referred areas of the TrPs. These results suggest that migraine pain is often contributed to by myofascial inputs that enhance the level of central neuronal excitability.

The importance of the external potential on group electronegativity.

PubMed

Leyssens, Tom; Geerlings, Paul; Peeters, Daniel

2005-11-03

The electronegativity of groups placed in a molecular environment is obtained using CCSD calculations of the electron affinity and ionization energy. A point charge model is used as an approximation of the molecular environment. The electronegativity values obtained in the presence of a point charge model are compared to the isolated group property to estimate the importance of the external potential on the group's electronegativity. The validity of the "group in molecule" electronegativities is verified by comparing EEM (electronegativity equalization method) charge transfer values to the explicitly calculated natural population analysis (NPA) ones, as well as by comparing the variation in electronegativity between the isolated functional group and the functional group in the presence of a modeled environment with the variation based on a perturbation expansion of the chemical potential.

Unitary cocycle representations of the Galilean line group: Quantum mechanical principle of equivalence

DOE Office of Scientific and Technical Information (OSTI.GOV)

MacGregor, B.R.; McCoy, A.E.; Wickramasekara, S., E-mail: wickrama@grinnell.edu

2012-09-15

We present a formalism of Galilean quantum mechanics in non-inertial reference frames and discuss its implications for the equivalence principle. This extension of quantum mechanics rests on the Galilean line group, the semidirect product of the real line and the group of analytic functions from the real line to the Euclidean group in three dimensions. This group provides transformations between all inertial and non-inertial reference frames and contains the Galilei group as a subgroup. We construct a certain class of unitary representations of the Galilean line group and show that these representations determine the structure of quantum mechanics in non-inertialmore » reference frames. Our representations of the Galilean line group contain the usual unitary projective representations of the Galilei group, but have a more intricate cocycle structure. The transformation formula for the Hamiltonian under the Galilean line group shows that in a non-inertial reference frame it acquires a fictitious potential energy term that is proportional to the inertial mass, suggesting the equivalence of inertial mass and gravitational mass in quantum mechanics. - Highlights: Black-Right-Pointing-Pointer A formulation of Galilean quantum mechanics in non-inertial reference frames is given. Black-Right-Pointing-Pointer The key concept is the Galilean line group, an infinite dimensional group. Black-Right-Pointing-Pointer Unitary, cocycle representations of the Galilean line group are constructed. Black-Right-Pointing-Pointer A non-central extension of the group underlies these representations. Black-Right-Pointing-Pointer Quantum equivalence principle and gravity emerge from these representations.« less

Point Clouds to Indoor/outdoor Accessibility Diagnosis

NASA Astrophysics Data System (ADS)

Balado, J.; Díaz-Vilariño, L.; Arias, P.; Garrido, I.

2017-09-01

This work presents an approach to automatically detect structural floor elements such as steps or ramps in the immediate environment of buildings, elements that may affect the accessibility to buildings. The methodology is based on Mobile Laser Scanner (MLS) point cloud and trajectory information. First, the street is segmented in stretches along the trajectory of the MLS to work in regular spaces. Next, the lower region of each stretch (the ground zone) is selected as the ROI and normal, curvature and tilt are calculated for each point. With this information, points in the ROI are classified in horizontal, inclined or vertical. Points are refined and grouped in structural elements using raster process and connected components in different phases for each type of previously classified points. At last, the trajectory data is used to distinguish between road and sidewalks. Adjacency information is used to classify structural elements in steps, ramps, curbs and curb-ramps. The methodology is tested in a real case study, consisting of 100 m of an urban street. Ground elements are correctly classified in an acceptable computation time. Steps and ramps also are exported to GIS software to enrich building models from Open Street Map with information about accessible/inaccessible entrances and their locations.

Space Shuttle Earth Observation sensors pointing and stabilization requirements study

NASA Technical Reports Server (NTRS)

1976-01-01

The shuttle orbiter inertial measurement unit (IMU), located in the orbiter cabin, is used to supply inertial attitude reference signals; and, in conjunction with the onboard navigation system, can provide a pointing capability of the navigation base accurate to within plus or minus 0.5 deg for earth viewing missions. This pointing accuracy can degrade to approximately plus or minus 2.0 deg for payloads located in the aft bay due to structural flexure of the shuttle vehicle, payload structural and mounting misalignments, and calibration errors with respect to the navigation base. Drawbacks to obtaining pointing accuracy by using the orbiter RCS jets are discussed. Supplemental electromechanical pointing systems are developed to provide independent pointing for individual sensors, or sensor groupings. The missions considered and the sensors required for these missions and the parameters of each sensor are described. Assumptions made to derive pointing and stabilization requirements are delineated.

Inelastic neutron scattering study of icosahedral AlFeCu quasicrystal

NASA Astrophysics Data System (ADS)

Quilichini, M.; Hennion, B.; Heger, G.; Lefebvre, S.; Quivy, A.

1992-02-01

Dynamical properties of quasiperiodic structures are rather tricky and far from being understood. For quasicrystals only little information is available both theoretically and experimentally. In this paper we present new experimental results obtained by inelastic neutron scattering on a monodomain quasicrystal of Al{63}Cu{25}Fe{12} already investigated in a previous study [1]. In section 1 we recall the basic features of the quasiperiodic structures and briefly review theoretical works on the dynamics of quasicrystals which can be of some help to appreciate the experimental data presented in section 2 and discussed in section 3. Les propriétés dynamiques des structures quasipériodiques sont complexes et pas encore complètement comprises. Pour les quasicristaux on ne possède que peu d'études dynamiques tant du point de vue théorique qu'expérimental. Dans cette lettre nous présentons des nouveaux résultats obtenus par diffusion inélastique de neutrons avec un quasicristal monodomaine de Al{63}Cu{25}Fe{12} que nous avions déjà étudié [1]. Dans la partie 1 nous rappelons quelques propriétés spécifiques des structures quasipériodiques et nous résumons brièvement les travaux théoriques qui nous permettent une interprétation qualitative des données expérimentales présentées dans la partie 2 et discutées dans la partie 3.

Effect of Electroacupuncture at The Zusanli Point (Stomach-36) on Dorsal Random Pattern Skin Flap Survival in a Rat Model.

PubMed

Wang, Li-Ren; Cai, Le-Yi; Lin, Ding-Sheng; Cao, Bin; Li, Zhi-Jie

2017-10-01

Random skin flaps are commonly used for wound repair and reconstruction. Electroacupuncture at The Zusanli point could enhance microcirculation and blood perfusion in random skin flaps. To determine whether electroacupuncture at The Zusanli point can improve the survival of random skin flaps in a rat model. Thirty-six male Sprague Dawley rats were randomly divided into 3 groups: control group (no electroacupuncture), Group A (electroacupuncture at a nonacupoint near The Zusanli point), and Group B (electroacupuncture at The Zusanli point). McFarlane flaps were established. On postoperative Day 2, malondialdehyde (MDA) and superoxide dismutase were detected. The flap survival rate was evaluated, inflammation was examined in hematoxylin and eosin-stained slices, and the expression of vascular endothelial growth factor (VEGF) was measured immunohistochemically on Day 7. The mean survival area of the flaps in Group B was significantly larger than that in the control group and Group A. Superoxide dismutase activity and VEGF expression level were significantly higher in Group B than those in the control group and Group A, whereas MDA and inflammation levels in Group B were significantly lower than those in the other 2 groups. Electroacupuncture at The Zusanli point can effectively improve the random flap survival.

The microviridae: Diversity, assembly, and experimental evolution.

PubMed

Doore, Sarah M; Fane, Bentley A

2016-04-01

The Microviridae, comprised of ssDNA, icosahedral bacteriophages, are a model system for studying morphogenesis and the evolution of assembly. Historically limited to the φX174-like viruses, recent results demonstrate that this richly diverse family is broadly divided into two groups. The defining feature appears to be whether one or two scaffolding proteins are required for assembly. The single-scaffolding systems contain an internal scaffolding protein, similar to many dsDNA viruses, and have a more complex coat protein fold. The two-scaffolding protein systems (φX174-like) encode an internal and external species, as well as an additional structural protein: a spike on the icosahedral vertices. Here, we discuss recent in silico and in vivo evolutionary analyses conducted with chimeric viruses and/or chimeric proteins. The results suggest 1) how double scaffolding systems can evolve into single and triple scaffolding systems; and 2) how assembly is the critical factor governing adaptation and the maintenance of species boundaries. Copyright © 2016 Elsevier Inc. All rights reserved.

Fast, adaptive summation of point forces in the two-dimensional Poisson equation

NASA Technical Reports Server (NTRS)

Van Dommelen, Leon; Rundensteiner, Elke A.

1989-01-01

A comparatively simple procedure is presented for the direct summation of the velocity field introduced by point vortices which significantly reduces the required number of operations by replacing selected partial sums by asymptotic series. Tables are presented which demonstrate the speed of this algorithm in terms of the mere doubling of computational time in dealing with a doubling of the number of vortices; current methods involve a computational time extension by a factor of 4. This procedure need not be restricted to the solution of the Poisson equation, and may be applied to other problems involving groups of points in which the interaction between elements of different groups can be simplified when the distance between groups is sufficiently great.

Tunnel Point Cloud Filtering Method Based on Elliptic Cylindrical Model

NASA Astrophysics Data System (ADS)

Zhua, Ningning; Jiaa, Yonghong; Luo, Lun

2016-06-01

The large number of bolts and screws that attached to the subway shield ring plates, along with the great amount of accessories of metal stents and electrical equipments mounted on the tunnel walls, make the laser point cloud data include lots of non-tunnel section points (hereinafter referred to as non-points), therefore affecting the accuracy for modeling and deformation monitoring. This paper proposed a filtering method for the point cloud based on the elliptic cylindrical model. The original laser point cloud data was firstly projected onto a horizontal plane, and a searching algorithm was given to extract the edging points of both sides, which were used further to fit the tunnel central axis. Along the axis the point cloud was segmented regionally, and then fitted as smooth elliptic cylindrical surface by means of iteration. This processing enabled the automatic filtering of those inner wall non-points. Experiments of two groups showed coincident results, that the elliptic cylindrical model based method could effectively filter out the non-points, and meet the accuracy requirements for subway deformation monitoring. The method provides a new mode for the periodic monitoring of tunnel sections all-around deformation in subways routine operation and maintenance.

Relativity, Symmetry, and the Structure of Quantum Theory, Volume 2; Point form relativistic quantum mechanics

NASA Astrophysics Data System (ADS)

Klink, William H.; Schweiger, Wolfgang

2018-03-01

This book covers relativistic quantum theory from the point of view of a particle theory, based on the irreducible representations of the Poincaré group, the group that expresses the symmetry of Einstein relativity. There are several ways of formulating such a theory; this book develops what is called relativistic point form quantum mechanics, which, unlike quantum field theory, deals with a fixed number of particles in a relativistically invariant way. A chapter is devoted to applications of point form quantum mechanics to nuclear physics.

Emerging Fixation Technique to Prevent Pectus Bar Displacement: Needlescope-Assisted 3-Point Fixation.

PubMed

Yoo, Gyeol; Rha, Eun Young; Jeong, Jin Yong; Lee, Jongho; Sim, Sung Bo; Jo, Keon Hyon

2016-01-01

Bar flipping displacement is one of the most common complications after the Nuss procedure for pectus excavatum. We evaluated the results of a modified Nuss procedure with needlescope-assisted bar fixation. The records of 41 patients with pectus excavatum who underwent single pectus bar insertion with the Nuss procedure between July 2011 and August 2014 were retrospectively reviewed. The patients were divided into two groups: those who did not undergo 3-point fixation (group A) and those who did undergo 3-point fixation (group B). There were 36 male patients and 5 female patients with a mean age of 10.7 ± 8.3 years (range: 3-36 years). The postoperative Haller index (HI) (2.61 ± 0.42) was significantly lower than the preoperative HI (3.91 ± 1.07; p < 0.01). The angle of the initial bar position was 5.59 ± 7.37 degrees in group A and 8.52 ± 9.61 degrees in group B, with no significant difference between the groups (p > 0.05). The rate of reoperation to correct bar displacement was lower in group B (3.3%) than in group A (9.1%). Needlescope-assisted 3-point fixation of the bar was performed without an additional skin incision and showed a low rate of reoperation to correct displacement of the pectus bar. Georg Thieme Verlag KG Stuttgart · New York.

Validation of accelerometer cut points in toddlers with and without cerebral palsy.

PubMed

Oftedal, Stina; Bell, Kristie L; Davies, Peter S W; Ware, Robert S; Boyd, Roslyn N

2014-09-01

The purpose of this study was to validate uni- and triaxial ActiGraph cut points for sedentary time in toddlers with cerebral palsy (CP) and typically developing children (TDC). Children (n = 103, 61 boys, mean age = 2 yr, SD = 6 months, range = 1 yr 6 months-3 yr) were divided into calibration (n = 65) and validation (n = 38) samples with separate analyses for TDC (n = 28) and ambulant (Gross Motor Function Classification System I-III, n = 51) and nonambulant (Gross Motor Function Classification System IV-V, n = 25) children with CP. An ActiGraph was worn during a videotaped assessment. Behavior was coded as sedentary or nonsedentary. Receiver operating characteristic-area under the curve analysis determined the classification accuracy of accelerometer data. Predictive validity was determined using the Bland-Altman analysis. Classification accuracy for uniaxial data was fair for the ambulatory CP and TDC group but poor for the nonambulatory CP group. Triaxial data showed good classification accuracy for all groups. The uniaxial ambulatory CP and TDC cut points significantly overestimated sedentary time (bias = -10.5%, 95% limits of agreement [LoA] = -30.2% to 9.1%; bias = -17.3%, 95% LoA = -44.3% to 8.3%). The triaxial ambulatory and nonambulatory CP and TDC cut points provided accurate group-level measures of sedentary time (bias = -1.5%, 95% LoA = -20% to 16.8%; bias = 2.1%, 95% LoA = -17.3% to 21.5%; bias = -5.1%, 95% LoA = -27.5% to 16.1%). Triaxial accelerometers provide useful group-level measures of sedentary time in children with CP across the spectrum of functional abilities and TDC. Uniaxial cut points are not recommended.

Change Points in the Population Trends of Aerial-Insectivorous Birds in North America: Synchronized in Time across Species and Regions.

PubMed

Smith, Adam C; Hudson, Marie-Anne R; Downes, Constance M; Francis, Charles M

2015-01-01

North American populations of aerial insectivorous birds are in steep decline. Aerial insectivores (AI) are a group of bird species that feed almost exclusively on insects in flight, and include swallows, swifts, nightjars, and flycatchers. The causes of the declines are not well understood. Indeed, it is not clear when the declines began, or whether the declines are shared across all species in the group (e.g., caused by changes in flying insect populations) or specific to each species (e.g., caused by changes in species' breeding habitat). A recent study suggested that population trends of aerial insectivores changed for the worse in the 1980s. If there was such a change point in trends of the group, understanding its timing and geographic pattern could help identify potential causes of the decline. We used a hierarchical Bayesian, penalized regression spline, change point model to estimate group-level change points in the trends of 22 species of AI, across 153 geographic strata of North America. We found evidence for group-level change points in 85% of the strata. Change points for flycatchers (FC) were distinct from those for swallows, swifts and nightjars (SSN) across North America, except in the Northeast, where all AI shared the same group-level change points. During the 1980s, there was a negative change point across most of North America, in the trends of SSN. For FC, the group-level change points were more geographically variable, and in many regions there were two: a positive change point followed by a negative change point. This group-level synchrony in AI population trends is likely evidence of a response to a common environmental factor(s) with similar effects on many species across broad spatial extents. The timing and geographic patterns of the change points that we identify here should provide a spring-board for research into the causes behind aerial insectivore declines.

Change Points in the Population Trends of Aerial-Insectivorous Birds in North America: Synchronized in Time across Species and Regions

PubMed Central

Smith, Adam C.; Hudson, Marie-Anne R.; Downes, Constance M.; Francis, Charles M.

2015-01-01

North American populations of aerial insectivorous birds are in steep decline. Aerial insectivores (AI) are a group of bird species that feed almost exclusively on insects in flight, and include swallows, swifts, nightjars, and flycatchers. The causes of the declines are not well understood. Indeed, it is not clear when the declines began, or whether the declines are shared across all species in the group (e.g., caused by changes in flying insect populations) or specific to each species (e.g., caused by changes in species’ breeding habitat). A recent study suggested that population trends of aerial insectivores changed for the worse in the 1980s. If there was such a change point in trends of the group, understanding its timing and geographic pattern could help identify potential causes of the decline. We used a hierarchical Bayesian, penalized regression spline, change point model to estimate group-level change points in the trends of 22 species of AI, across 153 geographic strata of North America. We found evidence for group-level change points in 85% of the strata. Change points for flycatchers (FC) were distinct from those for swallows, swifts and nightjars (SSN) across North America, except in the Northeast, where all AI shared the same group-level change points. During the 1980s, there was a negative change point across most of North America, in the trends of SSN. For FC, the group-level change points were more geographically variable, and in many regions there were two: a positive change point followed by a negative change point. This group-level synchrony in AI population trends is likely evidence of a response to a common environmental factor(s) with similar effects on many species across broad spatial extents. The timing and geographic patterns of the change points that we identify here should provide a spring-board for research into the causes behind aerial insectivore declines. PMID:26147572

Capacity Estimation Model for Signalized Intersections under the Impact of Access Point

PubMed Central

Zhao, Jing; Li, Peng; Zhou, Xizhao

2016-01-01

Highway Capacity Manual 2010 provides various factors to adjust the base saturation flow rate for the capacity analysis of signalized intersections. No factors, however, is considered for the potential change of signalized intersections capacity caused by the access point closeing to the signalized intersection. This paper presented a theoretical model to estimate the lane group capacity at signalized intersections with the consideration of the effects of access points. Two scenarios of access point locations, upstream or downstream of the signalized intersection, and impacts of six types of access traffic flow are taken into account. The proposed capacity model was validated based on VISSIM simulation. Results of extensive numerical analysis reveal the substantial impact of access point on the capacity, which has an inverse correlation with both the number of major street lanes and the distance between the intersection and access point. Moreover, among the six types of access traffic flows, the access traffic flow 1 (right-turning traffic from major street), flow 4 (left-turning traffic from access point), and flow 5 (left-turning traffic from major street) cause a more significant effect on lane group capacity than others. Some guidance on the mitigation of the negative effect is provided for practitioners. PMID:26726998

FPFH-based graph matching for 3D point cloud registration

NASA Astrophysics Data System (ADS)

Zhao, Jiapeng; Li, Chen; Tian, Lihua; Zhu, Jihua

2018-04-01

Correspondence detection is a vital step in point cloud registration and it can help getting a reliable initial alignment. In this paper, we put forward an advanced point feature-based graph matching algorithm to solve the initial alignment problem of rigid 3D point cloud registration with partial overlap. Specifically, Fast Point Feature Histograms are used to determine the initial possible correspondences firstly. Next, a new objective function is provided to make the graph matching more suitable for partially overlapping point cloud. The objective function is optimized by the simulated annealing algorithm for final group of correct correspondences. Finally, we present a novel set partitioning method which can transform the NP-hard optimization problem into a O(n3)-solvable one. Experiments on the Stanford and UWA public data sets indicates that our method can obtain better result in terms of both accuracy and time cost compared with other point cloud registration methods.

Formation mechanism of atomic cluster structures in Al-Mg alloy during rapid solidification processes

NASA Astrophysics Data System (ADS)

Liu, Feng-xiang; Liu, Rang-su; Hou, Zhao-yang; Liu, Hai-Rong; Tian, Ze-an; Zhou, Li-li

2009-02-01

The rapid solidification processes of Al 50Mg 50 liquid alloy consisting of 50,000 atoms have been simulated by using molecular dynamics method based on the effective pair potential derived from the pseudopotential theory. The formation mechanisms of atomic clusters during the rapid solidification processes have been investigated adopting a new cluster description method—cluster-type index method (CTIM). The simulated partial structure factors are in good agreement with the experimental results. And Al-Mg amorphous structure characterized with Al-centered icosahedral topological short-range order (SRO) is found to form during the rapid solidification processes. The icosahedral cluster plays a key role in the microstructure transition. Besides, it is also found that the size distribution of various clusters in the system presents a magic number sequence of 13, 19, 23, 25, 29, 31, 33, 37, …. The magic clusters are more stable and mainly correspond to the incompact arrangements of linked icosahedra in the form of rings, chains or dendrites. And each magic number point stands correspondingly for one certain combining form of icosahedra. This magic number sequence is different from that generated in the solidification structure of liquid Al and those obtained by methods of gaseous deposition and ionic spray, etc.

2. HORSESHOE CURVE IN GLACIER POINT ROAD NEAR GLACIER POINT. ...

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

2. HORSESHOE CURVE IN GLACIER POINT ROAD NEAR GLACIER POINT. HALF DOME AT CENTER REAR. LOOKING NNE. GIS N-37 43 44.3 / W-119 34 14.1 - Glacier Point Road, Between Chinquapin Flat & Glacier Point, Yosemite Village, Mariposa County, CA

Positive Feeling, Negative Meaning: Visualizing the Mental Representations of In-Group and Out-Group Smiles

PubMed Central

Dotsch, Ron; Wentura, Dirk

2016-01-01

Even though smiles are seen as universal facial expressions, research shows that there exist various kinds of smiles (i.e., affiliative smiles, dominant smiles). Accordingly, we suggest that there also exist various mental representations of smiles. Which representation is employed in cognition may depend on social factors, such as the smiling person’s group membership: Since in-group members are typically seen as more benevolent than out-group members, in-group smiles should be associated with more benevolent social meaning than those conveyed by out-group members. We visualized in-group and out-group smiles with reverse correlation image classification. These visualizations indicated that mental representations of in-group smiles indeed express more benevolent social meaning than those of out-group smiles. The affective meaning of these visualized smiles was not influenced by group membership. Importantly, the effect occurred even though participants were not instructed to attend to the nature of the smile, pointing to an automatic association between group membership and intention. PMID:26963621

Teaching Group Work with "The Great Debaters"

ERIC Educational Resources Information Center

Moe, Jeffry; Autry, Linda; Olson, Joann S.; Johnson, Kaprea F.

2014-01-01

An experiential learning activity, based on the film "The Great Debaters" (Washington, D., 2007), was used during a group work class. Description and preliminary evaluation of the activity is provided, including analysis of participant scores on the group leader self-efficacy instrument at multiple points. Implications and future…

A Model of Small Group Facilitator Competencies

ERIC Educational Resources Information Center

Kolb, Judith A.; Jin, Sungmi; Song, Ji Hoon

2008-01-01

This study used small group theory, quantitative and qualitative data collected from experienced practicing facilitators at three points of time, and a building block process of collection, analysis, further collection, and consolidation to develop a model of small group facilitator competencies. The proposed model has five components:…

Estimation of Melting Points of Organics.

PubMed

Yalkowsky, Samuel H; Alantary, Doaa

2018-05-01

Unified physicochemical property estimation relationships is a system of empirical and theoretical relationships that relate 20 physicochemical properties of organic molecules to each other and to chemical structure. Melting point is a key parameter in the unified physicochemical property estimation relationships scheme because it is a determinant of several other properties including vapor pressure, and solubility. This review describes the first-principals calculation of the melting points of organic compounds from structure. The calculation is based on the fact that the melting point, T m , is equal to the ratio of the heat of melting, ΔH m , to the entropy of melting, ΔS m . The heat of melting is shown to be an additive constitutive property. However, the entropy of melting is not entirely group additive. It is primarily dependent on molecular geometry, including parameters which reflect the degree of restriction of molecular motion in the crystal to that of the liquid. Symmetry, eccentricity, chirality, flexibility, and hydrogen bonding, each affect molecular freedom in different ways and thus make different contributions to the total entropy of fusion. The relationships of these entropy determining parameters to chemical structure are used to develop a reasonably accurate means of predicting the melting points over 2000 compounds. Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Microcurrent Point Stimulation Applied to Lower Back Acupuncture Points for the Treatment of Nonspecific Neck Pain.

PubMed

Armstrong, Kelly; Gokal, Raman; Chevalier, Antoine; Todorsky, William; Lim, Mike

2017-04-01

Although acupuncture and microcurrent are widely used for chronic pain, there remains considerable controversy as to their therapeutic value for neck pain. We aimed to determine the effect size of microcurrent applied to lower back acupuncture points to assess the impact on the neck pain. This was a cohort analysis of treatment outcomes pre- and postmicrocurrent stimulation, involving 34 patients with a history of nonspecific chronic neck pain. Consenting patients were enrolled from a group of therapists attending educational seminars and were asked to report pain levels pre-post and 48 hours after a single MPS application. Direct current microcurrent point stimulation (MPS) applied to standardized lower back acupuncture protocol points was used. Evaluations entailed a baseline visual analog scale (VAS) pain scale assessment, using a VAS, which was repeated twice after therapy, once immediately postelectrotherapy and again after a 48-h follow-up period. All 34 patients received a single MPS session. Results were analyzed using paired t tests. Results and Outcomes: Pain intensity showed an initial statistically significant reduction of 68% [3.9050 points; 95% CI (2.9480, 3.9050); p = 0.0001], in mean neck pain levels after standard protocol treatment, when compared to initial pain levels. There was a further statistically significant reduction of 35% in mean neck pain levels at 48 h when compared to pain levels immediately after standard protocol treatment [0.5588 points; 95% CI (0.2001, 0.9176); p = 0.03], for a total average pain relief of 80%. The positive results in this study could have applications for those patients impacted by chronic neck pain.

Revising two-point discrimination assessment in normal aging and in patients with polyneuropathies.

PubMed

van Nes, S I; Faber, C G; Hamers, R M T P; Harschnitz, O; Bakkers, M; Hermans, M C E; Meijer, R J; van Doorn, P A; Merkies, I S J

2008-07-01

To revise the static and dynamic normative values for the two-point discrimination test and to examine its applicability and validity in patients with a polyneuropathy. Two-point discrimination threshold values were assessed in 427 healthy controls and 99 patients mildly affected by a polyneuropathy. The controls were divided into seven age groups ranging from 20-29, 30-39,..., up to 80 years and older; each group consisted of at least 30 men and 30 women. Two-point discrimination examination took place under standardised conditions on the index finger. Correlation studies were performed between the scores obtained and the values derived from the Weinstein Enhanced Sensory Test (WEST) and the arm grade of the Overall Disability SumScore (ODSS) in the patients' group (validity studies). Finally, the sensitivity to detect patients mildly affected by a polyneuropathy was evaluated for static and dynamic assessments. There was a significant age-dependent increase in the two-point discrimination values. No significant gender difference was found. The dynamic threshold values were lower than the static scores. The two-point discrimination values obtained correlated significantly with the arm grade of the ODSS (static values: r = 0.33, p = 0.04; dynamic values: r = 0.37, p = 0.02) and the scores of the WEST in patients (static values: r = 0.58, p = 0.0001; dynamic values: r = 0.55, p = 0.0002). The sensitivity for the static and dynamic threshold values was 28% and 33%, respectively. This study provides age-related normative two-point discrimination threshold values using a two-point discriminator (an aesthesiometer). This easily applicable instrument could be used as part of a more extensive neurological sensory evaluation.

Introduction to sporadic groups for physicists

NASA Astrophysics Data System (ADS)

Boya, Luis J.

2013-04-01

We describe the collection of finite simple groups, with a view to physical applications. We recall first the prime cyclic groups Zp and the alternating groups Altn > 4. After a quick revision of finite fields {F}_q, q = pf, with p prime, we consider the 16 families of finite simple groups of Lie type. There are also 26 extra ‘sporadic’ groups, which gather in three interconnected ‘generations’ (with 5+7+8 groups) plus the pariah groups (6). We point out a couple of physical applications, including constructing the biggest sporadic group, the ‘Monster’ group, with close to 1054 elements from arguments of physics, and also the relation of some Mathieu groups with compactification in string and M-theory. This article is dedicated to the memory of Juan Sancho Guimerá.

HORSESHOE CURVE IN GLACIER POINT ROAD NEAR GLACIER POINT. HALF ...

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

HORSESHOE CURVE IN GLACIER POINT ROAD NEAR GLACIER POINT. HALF DOME AT CENTER REAR. SAME VIEW AT CA-157-2. LOOKING NNE. GIS: N-37' 43 44.3 / W-119 34 14.1 - Glacier Point Road, Between Chinquapin Flat & Glacier Point, Yosemite Village, Mariposa County, CA

Evaluation of three point-of-care healthcare databases: BMJ Point-of-Care, Clin-eguide and Nursing Reference Centre.

PubMed

Chan, Rachel; Stieda, Vivian

2011-03-01

  Point of care resources make it easier for clinicians to find answers to questions that arise during a clinical encounter. In order to make informed purchase decisions in times of tight budgets, librarians need to have a better understanding of which resources will meet their patrons' clinical information needs.   The goal of this study was to assess the content, interface and usability of three point-of-care tools: BMJ Point-of-Care, Clin-eguide and Nursing Reference Centre.   A questionnaire designed to gather quantitative and qualitative data was created using Survey Monkey. The survey was distributed to healthcare practitioners in Alberta's two largest health regions, and the data were analysed for emergent themes.   The themes that arose--ease of use, validated content, relevancy to practice--generally echoed those stated in the literature. No one database fared significantly better, due to differing features, content and client preference.   Despite the limitations of the survey, the themes that emerged provide a springboard for future research on the efficacy of information resources used at the point of care, and the need for deeper analysis of these recent additions to the medical information market. © 2010 The authors. Health Information and Libraries Journal © 2010 Health Libraries Group.

The effect of Health Savings Accounts on group health insurance coverage.

PubMed

Ye, Jinqi

2015-12-01

This paper presents new empirical evidence on the impact of tax subsidies for Health Savings Accounts (HSAs) on group insurance coverage. HSAs are tax-free health care expenditure savings accounts. Coupled with high deductible health insurance plans (HDHPs), they together represent new health insurance options. The tax advantage of HSAs expands the group health insurance market by making health care more affordable. Using individual level data from the Current Population Survey and exploiting policy variation by state and year from 2004 to 2012, I find that HSA tax subsidies increase small-group coverage by a statistically significant 2.5 percentage points, although not coverage in larger firms. Moreover, if the tax price of HSA contribution decreases by 10 cents, small-group insurance coverage increases by almost 2 percentage points. I also find that for older workers or less-educated workers, HSA subsidies are associated with 2-3 percentage point increase in their group insurance coverage. Copyright © 2015 Elsevier B.V. All rights reserved.

A point particle model of lightly bound skyrmions

NASA Astrophysics Data System (ADS)

Gillard, Mike; Harland, Derek; Kirk, Elliot; Maybee, Ben; Speight, Martin

2017-04-01

A simple model of the dynamics of lightly bound skyrmions is developed in which skyrmions are replaced by point particles, each carrying an internal orientation. The model accounts well for the static energy minimizers of baryon number 1 ≤ B ≤ 8 obtained by numerical simulation of the full field theory. For 9 ≤ B ≤ 23, a large number of static solutions of the point particle model are found, all closely resembling size B subsets of a face centred cubic lattice, with the particle orientations dictated by a simple colouring rule. Rigid body quantization of these solutions is performed, and the spin and isospin of the corresponding ground states extracted. As part of the quantization scheme, an algorithm to compute the symmetry group of an oriented point cloud, and to determine its corresponding Finkelstein-Rubinstein constraints, is devised.

Functional renormalization group analysis of tensorial group field theories on Rd

NASA Astrophysics Data System (ADS)

Geloun, Joseph Ben; Martini, Riccardo; Oriti, Daniele

2016-07-01

Rank-d tensorial group field theories are quantum field theories (QFTs) defined on a group manifold G×d , which represent a nonlocal generalization of standard QFT and a candidate formalism for quantum gravity, since, when endowed with appropriate data, they can be interpreted as defining a field theoretic description of the fundamental building blocks of quantum spacetime. Their renormalization analysis is crucial both for establishing their consistency as quantum field theories and for studying the emergence of continuum spacetime and geometry from them. In this paper, we study the renormalization group flow of two simple classes of tensorial group field theories (TGFTs), defined for the group G =R for arbitrary rank, both without and with gauge invariance conditions, by means of functional renormalization group techniques. The issue of IR divergences is tackled by the definition of a proper thermodynamic limit for TGFTs. We map the phase diagram of such models, in a simple truncation, and identify both UV and IR fixed points of the RG flow. Encouragingly, for all the models we study, we find evidence for the existence of a phase transition of condensation type.

Pointing to others: How the target gender influences pointing performance.

PubMed

Cleret de Langavant, Laurent; Jacquemot, Charlotte; Cruveiller, Virginie; Dupoux, Emmanuel; Bachoud-Lévi, Anne-Catherine

2016-01-01

Pointing is a communicative gesture that allows individuals to share information about surrounding objects with other humans. Patients with heterotopagnosia are specifically impaired in pointing to other humans' body parts but not in pointing to themselves or to objects. Here, we describe a female patient with heterotopagnosia who was more accurate in pointing to men's body parts than to women's body parts. We replicated this gender effect in healthy participants with faster reaction times for pointing to men's body parts than to women's body parts. We discuss the role of gender stereotypes in explaining why it is more difficult to point to women than to men.

The Effect of Transcutaneous Electrical Nerve Stimulation of Sympathetic Ganglions and Acupuncture Points on Distal Blood Flow.

PubMed

Kamali, Fahimeh; Mirkhani, Hossein; Nematollahi, Ahmadreza; Heidari, Saeed; Moosavi, Elahesadat; Mohamadi, Marzieh

2017-04-01

Transcutaneous electrical nerve stimulation (TENS) is a widely-practiced method to increase blood flow in clinical practice. The best location for stimulation to achieve optimal blood flow has not yet been determined. We compared the effect of TENS application at sympathetic ganglions and acupuncture points on blood flow in the foot of healthy individuals. Seventy-five healthy individuals were randomly assigned to three groups. The first group received cutaneous electrical stimulation at the thoracolumbar sympathetic ganglions. The second group received stimulation at acupuncture points. The third group received stimulation in the mid-calf area as a control group. Blood flow was recorded at time zero as baseline and every 3 minutes after baseline during stimulation, with a laser Doppler flow-meter. Individuals who received sympathetic ganglion stimulation showed significantly greater blood flow than those receiving acupuncture point stimulation or those in the control group (p<0.001). Data analysis revealed that blood flow at different times during stimulation increased significantly from time zero in each group. Therefore, the application of low-frequency TENS at the thoracolumbar sympathetic ganglions was more effective in increasing peripheral blood circulation than stimulation at acupuncture points. Copyright © 2017 Medical Association of Pharmacopuncture Institute. Published by Elsevier B.V. All rights reserved.

Formation of fivefold axes in the FCC-metal nanoclusters

NASA Astrophysics Data System (ADS)

Myasnichenko, Vladimir S.; Starostenkov, Mikhail D.

2012-11-01

Formation of atomistic structures of metallic Cu, Au, Ag clusters and bimetallic Cu-Au clusters was studied with the help of molecular dynamics using the many-body tight-binding interatomic potential. The simulation of the crystallization process of clusters with the number of atoms ranging from 300 to 1092 was carried out. The most stable configurations of atoms in the system, corresponding to the minimum of potential energy, was found during super-fast cooling from 1000 K. Atoms corresponding to fcc, hcp, and Ih phases were identified by the method of common neighbor analysis. Incomplete icosahedral core can be discovered at the intersection of one of the Ih axes with the surface of monometallic cluster. The decahedron-shaped structure of bimetallic Cu-Au cluster with seven completed icosahedral cores was obtained. The principles of the construction of small bimetallic clusters with icosahedral symmetry and increased fractal dimensionality were offered.

Maxwell Strata and Cut Locus in the Sub-Riemannian Problem on the Engel Group

NASA Astrophysics Data System (ADS)

Ardentov, Andrei A.; Sachkov, Yuri L.

2017-12-01

We consider the nilpotent left-invariant sub-Riemannian structure on the Engel group. This structure gives a fundamental local approximation of a generic rank 2 sub-Riemannian structure on a 4-manifold near a generic point (in particular, of the kinematic models of a car with a trailer). On the other hand, this is the simplest sub-Riemannian structure of step three. We describe the global structure of the cut locus (the set of points where geodesics lose their global optimality), the Maxwell set (the set of points that admit more than one minimizer), and the intersection of the cut locus with the caustic (the set of conjugate points along all geodesics). The group of symmetries of the cut locus is described: it is generated by a one-parameter group of dilations R+ and a discrete group of reflections Z2 × Z2 × Z2. The cut locus admits a stratification with 6 three-dimensional strata, 12 two-dimensional strata, and 2 one-dimensional strata. Three-dimensional strata of the cut locus are Maxwell strata of multiplicity 2 (for each point there are 2 minimizers). Two-dimensional strata of the cut locus consist of conjugate points. Finally, one-dimensional strata are Maxwell strata of infinite multiplicity, they consist of conjugate points as well. Projections of sub-Riemannian geodesics to the 2-dimensional plane of the distribution are Euler elasticae. For each point of the cut locus, we describe the Euler elasticae corresponding to minimizers coming to this point. Finally, we describe the structure of the optimal synthesis, i. e., the set of minimizers for each terminal point in the Engel group.

7 CFR 29.2437 - Heavy Leaf (B Group).

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 2 2013-01-01 2013-01-01 false Heavy Leaf (B Group). 29.2437 Section 29.2437... REGULATIONS TOBACCO INSPECTION Standards Grades § 29.2437 Heavy Leaf (B Group). This group consists of leaves usually grown at or above the center portion of the stalk. These leaves have a pointed tip, tend to fold...

7 CFR 29.2437 - Heavy Leaf (B Group).

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 2 2012-01-01 2012-01-01 false Heavy Leaf (B Group). 29.2437 Section 29.2437... REGULATIONS TOBACCO INSPECTION Standards Grades § 29.2437 Heavy Leaf (B Group). This group consists of leaves usually grown at or above the center portion of the stalk. These leaves have a pointed tip, tend to fold...

7 CFR 29.2437 - Heavy Leaf (B Group).

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 2 2014-01-01 2014-01-01 false Heavy Leaf (B Group). 29.2437 Section 29.2437... REGULATIONS TOBACCO INSPECTION Standards Grades § 29.2437 Heavy Leaf (B Group). This group consists of leaves usually grown at or above the center portion of the stalk. These leaves have a pointed tip, tend to fold...

Designs for Testing Group-Based Interventions with Limited Numbers of Social Units: The Dynamic Wait-Listed and Regression Point Displacement Designs.

PubMed

Wyman, Peter A; Henry, David; Knoblauch, Shannon; Brown, C Hendricks

2015-10-01

The dynamic wait-listed design (DWLD) and regression point displacement design (RPDD) address several challenges in evaluating group-based interventions when there is a limited number of groups. Both DWLD and RPDD utilize efficiencies that increase statistical power and can enhance balance between community needs and research priorities. The DWLD blocks on more time units than traditional wait-listed designs, thereby increasing the proportion of a study period during which intervention and control conditions can be compared, and can also improve logistics of implementing intervention across multiple sites and strengthen fidelity. We discuss DWLDs in the larger context of roll-out randomized designs and compare it with its cousin the Stepped Wedge design. The RPDD uses archival data on the population of settings from which intervention unit(s) are selected to create expected posttest scores for units receiving intervention, to which actual posttest scores are compared. High pretest-posttest correlations give the RPDD statistical power for assessing intervention impact even when one or a few settings receive intervention. RPDD works best when archival data are available over a number of years prior to and following intervention. If intervention units were not randomly selected, propensity scores can be used to control for non-random selection factors. Examples are provided of the DWLD and RPDD used to evaluate, respectively, suicide prevention training (QPR) in 32 schools and a violence prevention program (CeaseFire) in two Chicago police districts over a 10-year period. How DWLD and RPDD address common threats to internal and external validity, as well as their limitations, are discussed.

Designs for testing group-based interventions with limited numbers of social units: The dynamic wait-listed and regression point displacement designs

PubMed Central

Wyman, Peter A.; Brown, C. Hendricks

2015-01-01

The dynamic wait-listed design (DWLD) and regression point displacement design (RPDD) address several challenges in evaluating group-based interventions when there is a limited number of groups. Both DWLD and RPDD utilize efficiencies that increase statistical power and can enhance balance between community needs and research priorities. The DWLD blocks on more time units than traditional wait-listed designs, thereby increasing the proportion of a study period during which intervention and control conditions can be compared, and can also improve logistics of implementing intervention across multiple sites and strengthen fidelity. We discuss DWLDs in the larger context of roll-out randomized designs and compare it with its cousin the Stepped Wedge design. The RPDD uses archival data on the population of settings from which intervention unit(s) are selected to create expected posttest scores for units receiving intervention, to which actual posttest scores are compared. High pretest-posttest correlations give the RPDD statistical power for assessing intervention impact even when one or a few settings receive intervention. RPDD works best when archival data are available over a number of years prior to and following intervention. If intervention units were not randomly selected, propensity scores can be used to control for nonrandom selection factors. Examples are provided of the DWLD and RPDD used to evaluate, respectively, suicide prevention training (QPR) in 32 schools and a violence prevention program (CeaseFire) in 2 Chicago police districts over a 10-year period. How DWLD and RPDD address common threats to internal and external validity, as well as their limitations, are discussed. PMID:25481512

New Icosahedral Boron Carbide Semiconductors

NASA Astrophysics Data System (ADS)

Echeverria Mora, Elena Maria

Novel semiconductor boron carbide films and boron carbide films doped with aromatic compounds have been investigated and characterized. Most of these semiconductors were formed by plasma enhanced chemical vapor deposition. The aromatic compound additives used, in this thesis, were pyridine (Py), aniline, and diaminobenzene (DAB). As one of the key parameters for semiconducting device functionality is the metal contact and, therefore, the chemical interactions or band bending that may occur at the metal/semiconductor interface, X-ray photoemission spectroscopy has been used to investigate the interaction of gold (Au) with these novel boron carbide-based semiconductors. Both n- and p-type films have been tested and pure boron carbide devices are compared to those containing aromatic compounds. The results show that boron carbide seems to behave differently from other semiconductors, opening a way for new analysis and approaches in device's functionality. By studying the electrical and optical properties of these films, it has been found that samples containing the aromatic compound exhibit an improvement in the electron-hole separation and charge extraction, as well as a decrease in the band gap. The hole carrier lifetimes for each sample were extracted from the capacitance-voltage, C(V), and current-voltage, I(V), curves. Additionally, devices, with boron carbide with the addition of pyridine, exhibited better collection of neutron capture generated pulses at ZERO applied bias, compared to the pure boron carbide samples. This is consistent with the longer carrier lifetimes estimated for these films. The I-V curves, as a function of external magnetic field, of the pure boron carbide films and films containing DAB demonstrate that significant room temperature negative magneto-resistance (> 100% for pure samples, and > 50% for samples containing DAB) is possible in the resulting dielectric thin films. Inclusion of DAB is not essential for significant negative magneto-resistance, however, these results suggest practical device applications, especially as such effects are manifested in nanoscale films with facile fabrication. Overall, the greater negative magneto-resistance, when undoped with an aromatic, suggests a material with more defects and is consistent with a shorter carrier lifetime.

Point-to-point people with purpose—Exploring the possibility of a commercial traveler market for point-to-point suborbital space transportation

NASA Astrophysics Data System (ADS)

Webber, Derek

2013-12-01

An argument was made at the First Arcachon Conference on Private Human Access to Space in 2008 [1] that some systematic market research should be conducted into potential market segments for point-to-point suborbital space transportation (PtP), in order to understand whether a commercial market exists which might augment possible government use for such a vehicle. The cargo market potential was subsequently addressed via desk research, and the results, which resulted in a pessimistic business case outlook, were presented in [2]. The same desk research approach is now used in this paper to address the potential business and wealthy individual passenger traveler market segment ("point-to-point people with purpose"). The results, with the assumed ticket pricing, are not encouraging.

Effects of point massage of liver and stomach channel combined with pith and trotter soup on postpartum lactation start time.

PubMed

Luo, Qiong; Hu, Yin; Zhang, Hui

2017-10-01

Delay in lactation initiation causes maternal anxiety and subsequent adverse impact on maternal exclusive breast feeding. It is important to explore a safe and convenient way to promote lactation initiation. The feasibility of point massage of liver and stomach channel combined with pith and trotter soup on prevention of delayed lactation initiation was investigated in the present study. 320 women were enrolled and randomly divided into four groups, control group (80 women), point massage group (80 women), pith and trotter soup group (80 women), and massage + soup group (80 women) to compare the lactation initiation time. We found that women in point massage group, pith and trotter soup group and massage + soup group had earlier initiation of lactation compared with control group. Women in massage + soup group had the earliest initiation time of lactation. There were significant differences between massage + soup group and pith and trotter soup group. But, there were no significant differences between massage + soup group and massage group. We conclude that point massage of the liver and stomach channel is easy to operate and has the preventive effect on delayed lactation initiation. Impact statement What is already known on this subject: Initiation of lactation is a critical period in postpartum milk secretion. Delays in lactation initiation lead to maternal anxiety and have an adverse impact on maternal exclusive breastfeeding. Sucking frequently by babies and mammary massage might be effective but insufficient for delayed lactation initiation. What the results of this study add: We found in the present study that lactation initiation is significantly earlier in women receiving routine nursing combined with point massage of liver and stomach channel, or pith trotters soup, or massage of liver and stomach channel with pith and trotters soup than in a control group receiving routine nursing. These three methods are all effective, while the most

Group Cohesion DEOCS 4.1 Construct Validity Summary

DTIC Science & Technology

2017-08-01

Group Cohesion DEOCS 4.1 Construct Validity Summary DEFENSE EQUAL OPPORTUNITY MANAGEMENT INSTITUTE DIRECTORATE...See Table 4 for more information regarding item reliabilities. The relationship between the original four-point scale (Organizational Cohesion) and...future analyses, including those using the seven-point scale. Tables 4 and 5 provide additional information regarding the reliability and descriptive

Pivots for Pointing: Visually-Monitored Pointing Has Higher Arm Elevations than Pointing Blindfolded

ERIC Educational Resources Information Center

Wnuczko, Marta; Kennedy, John M.

2011-01-01

Observers pointing to a target viewed directly may elevate their fingertip close to the line of sight. However, pointing blindfolded, after viewing the target, they may pivot lower, from the shoulder, aligning the arm with the target as if reaching to the target. Indeed, in Experiment 1 participants elevated their arms more in visually monitored…

X-ray bright points and He I lambda 10830 dark points

NASA Technical Reports Server (NTRS)

Golub, L.; Harvey, K. L.; Herant, M.; Webb, D. F.

1989-01-01

Using near-simultaneous full disk Solar X-ray images and He I 10830 lambda, spectroheliograms from three recent rocket flights, dark points identified on the He I maps were compared with X-ray bright points identified on the X-ray images. It was found that for the largest and most obvious features there is a strong correlation: most He I dark points correspond to X-ray bright points. However, about 2/3 of the X-ray bright points were not identified on the basis of the helium data alone. Once an X-ray feature is identified it is almost always possible to find an underlying dark patch of enhanced He I absorption which, however, would not a priori have been selected as a dark point. Therefore, the He I dark points, using current selection criteria, cannot be used as a one-to-one proxy for the X-ray data. He I dark points do, however, identify the locations of the stronger X-ray bright points.

X-ray bright points and He I lambda 10830 dark points

NASA Technical Reports Server (NTRS)

Golub, L.; Harvey, K. L.; Herant, M.; Webb, D. F.

1989-01-01

Using near-simultaneous full disk Solar X-ray images and He I 10830 lambda, spectroheliograms from three recent rocket flights, dark points identified on the He I maps were compared with x-ray bright points identified on the X-ray images. It was found that for the largest and most obvious features there is a strong correlation: most He I dark points correspond to X-ray bright points. However, about 2/3 of the X-ray bright points were not identified on the basis of the helium data alone. Once an X-ray feature is identified it is almost always possible to find an underlying dark patch of enhanced He I absorption which, however, would not a priori have been selected as a dark point. Therefore, the He I dark points, using current selection criteria, cannot be used as a one-to-one proxy for the X-ray data. He I dark points do, however, identify the locations of the stronger X-ray bright points.

Point-to-Point Multicast Communications Protocol

NASA Technical Reports Server (NTRS)

Byrd, Gregory T.; Nakano, Russell; Delagi, Bruce A.

1987-01-01

This paper describes a protocol to support point-to-point interprocessor communications with multicast. Dynamic, cut-through routing with local flow control is used to provide a high-throughput, low-latency communications path between processors. In addition multicast transmissions are available, in which copies of a packet are sent to multiple destinations using common resources as much as possible. Special packet terminators and selective buffering are introduced to avoid a deadlock during multicasts. A simulated implementation of the protocol is also described.

The acute benefits and risks of passive stretching to the point of pain.

PubMed

Muanjai, Pornpimol; Jones, David A; Mickevicius, Mantas; Satkunskiene, Danguole; Snieckus, Audrius; Skurvydas, Albertas; Kamandulis, Sigitas

2017-06-01

This study evaluated the acute effects of two different stretch intensities on muscle damage and extensibility. Twenty-two physically active women (age 20 ± 1.0 years) were divided into two matched groups and undertook eight sets of 30-s passive hamstring stretching. One group stretched to the point of discomfort (POD) and the other to the point of pain (POP). Hamstring passive torque, sit and reach (S&R), straight leg raise (SLR), and markers of muscle damage were measured before, immediately after stretching and 24 h later. S&R acutely increased and was still increased at 24 h with median (interquartile range) of 2.0 cm (0.5-3.75 cm) and 2.0 cm (0.25-3.0 cm) for POP and POD (p < 0.05), respectively, with no difference between groups; similar changes were seen with SLR. Passive stiffness fully recovered by 24 h and there was no torque deficit. A small, but significant increase in muscle tenderness occurred at 24 h in both groups and there was a very small increase in thigh circumference in both groups which persisted at 24 h in POP. Plasma CK activity was not raised at 24 h. Stretching to the point of pain had no acute advantages over stretching to the discomfort point. Both forms of stretching resulted in very mild muscle tenderness but with no evidence of muscle damage. The increased ROM was not associated with changes in passive stiffness of the muscle but most likely resulted from increased tolerance of the discomfort.

Spontaneous Group Learning in Ambient Learning Environments

NASA Astrophysics Data System (ADS)

Bick, Markus; Jughardt, Achim; Pawlowski, Jan M.; Veith, Patrick

Spontaneous Group Learning is a concept to form and facilitate face-to-face, ad-hoc learning groups in collaborative settings. We show how to use Ambient Intelligence to identify, support, and initiate group processes. Learners' positions are determined by widely used technologies, e.g., Bluetooth and WLAN. As a second step, learners' positions, tasks, and interests are visualized. Finally, a group process is initiated supported by relevant documents and services. Our solution is a starting point to develop new didactical solutions for collaborative processes.

Coronary risk assessment by point-based vs. equation-based Framingham models: significant implications for clinical care.

PubMed

Gordon, William J; Polansky, Jesse M; Boscardin, W John; Fung, Kathy Z; Steinman, Michael A

2010-11-01

US cholesterol guidelines use original and simplified versions of the Framingham model to estimate future coronary risk and thereby classify patients into risk groups with different treatment strategies. We sought to compare risk estimates and risk group classification generated by the original, complex Framingham model and the simplified, point-based version. We assessed 2,543 subjects age 20-79 from the 2001-2006 National Health and Nutrition Examination Surveys (NHANES) for whom Adult Treatment Panel III (ATP-III) guidelines recommend formal risk stratification. For each subject, we calculated the 10-year risk of major coronary events using the original and point-based Framingham models, and then compared differences in these risk estimates and whether these differences would place subjects into different ATP-III risk groups (<10% risk, 10-20% risk, or >20% risk). Using standard procedures, all analyses were adjusted for survey weights, clustering, and stratification to make our results nationally representative. Among 39 million eligible adults, the original Framingham model categorized 71% of subjects as having "moderate" risk (<10% risk of a major coronary event in the next 10 years), 22% as having "moderately high" (10-20%) risk, and 7% as having "high" (>20%) risk. Estimates of coronary risk by the original and point-based models often differed substantially. The point-based system classified 15% of adults (5.7 million) into different risk groups than the original model, with 10% (3.9 million) misclassified into higher risk groups and 5% (1.8 million) into lower risk groups, for a net impact of classifying 2.1 million adults into higher risk groups. These risk group misclassifications would impact guideline-recommended drug treatment strategies for 25-46% of affected subjects. Patterns of misclassifications varied significantly by gender, age, and underlying CHD risk. Compared to the original Framingham model, the point-based version misclassifies millions

Power in randomized group comparisons: the value of adding a single intermediate time point to a traditional pretest-posttest design.

PubMed

Venter, Anre; Maxwell, Scott E; Bolig, Erika

2002-06-01

Adding a pretest as a covariate to a randomized posttest-only design increases statistical power, as does the addition of intermediate time points to a randomized pretest-posttest design. Although typically 5 waves of data are required in this instance to produce meaningful gains in power, a 3-wave intensive design allows the evaluation of the straight-line growth model and may reduce the effect of missing data. The authors identify the statistically most powerful method of data analysis in the 3-wave intensive design. If straight-line growth is assumed, the pretest-posttest slope must assume fairly extreme values for the intermediate time point to increase power beyond the standard analysis of covariance on the posttest with the pretest as covariate, ignoring the intermediate time point.

Superconductivity in doped fullerenes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hebard, A.F.

1992-11-01

While there is not complete agreement on the microscopic mechanism of superconductivity in alkali-metal-doped C[sub 60], further research may well lead to the production of analogous materials that lose resistance at even higher temperatures. Carbon 60 is a fascinating and arrestingly beautiful molecule. With 12 pentagonal and 20 hexagonal faces symmetrically arrayed in a soccer-ball-like structure that belongs to the icosahedral point group, I[sub h], its high symmetry alone invites special attention. The publication in September 1990 of a simple technique for manufacturing and concentrating macroscopic amounts of this new form of carbon announced to the scientific community that enablingmore » technology had arrived. Macroscopic amounts of C[sub 60] (and the higher fullerenes, such as C[sub 70] and C[sub 84]) can now be made with an apparatus as simple as an arc furnace powered with an arc welding supply. Accordingly, chemists, physicists and materials scientists have joined forces in an explosion of effort to explore the properties of this unusual molecular building block. 23 refs., 6 figs.« less

Comparison of efficacy of pulverization and sterile paper point techniques for sampling root canals.

PubMed

Tran, Kenny T; Torabinejad, Mahmoud; Shabahang, Shahrokh; Retamozo, Bonnie; Aprecio, Raydolfo M; Chen, Jung-Wei

2013-08-01

The purpose of this study was to compare the efficacy of the pulverization and sterile paper point techniques for sampling root canals using 5.25% NaOCl/17% EDTA and 1.3% NaOCl/MTAD (Dentsply, Tulsa, OK) as irrigation regimens. Single-canal extracted human teeth were decoronated and infected with Enterococcus faecalis. Roots were randomly assigned to 2 irrigation regimens: group A with 5.25% NaOCl/17% EDTA (n = 30) and group B with 1.3% NaOCl/MTAD (n = 30). After chemomechanical debridement, bacterial samplings were taken using sterile paper points and pulverized powder of the apical 5 mm root ends. The sterile paper point technique did not show growth in any samples. The pulverization technique showed growth in 24 of the 60 samples. The Fisher exact test showed significant differences between sampling techniques (P < .001). The sterile paper point technique showed no difference between irrigation regimens. However, 17 of the 30 roots in group A and 7 of the 30 roots in group B resulted in growth as detected by pulverization technique. Data showed a significant difference between irrigation regimens (P = .03) in pulverization technique. The pulverization technique was more efficacious in detecting viable bacteria. Furthermore, this technique showed that 1.3% NaOCl/MTAD regimen was more effective in disinfecting root canals. Published by Elsevier Inc.

Vendor compliance with Ontario's tobacco point of sale legislation.

PubMed

Dubray, Jolene M; Schwartz, Robert M; Garcia, John M; Bondy, Susan J; Victor, J Charles

2009-01-01

On May 31, 2006, Ontario joined a small group of international jurisdictions to implement legislative restrictions on tobacco point of sale promotions. This study compares the presence of point of sale promotions in the retail tobacco environment from three surveys: one prior to and two following implementation of the legislation. Approximately 1,575 tobacco vendors were randomly selected for each survey. Each regionally-stratified sample included equal numbers of tobacco vendors categorized into four trade classes: chain convenience, independent convenience and discount, gas stations, and grocery. Data regarding the six restricted point of sale promotions were collected using standardized protocols and inspection forms. Weighted estimates and 95% confidence intervals were produced at the provincial, regional and vendor trade class level using the bootstrap method for estimating variance. At baseline, the proportion of tobacco vendors who did not engage in each of the six restricted point of sale promotions ranged from 41% to 88%. Within four months following implementation of the legislation, compliance with each of the six restricted point of sale promotions exceeded 95%. Similar levels of compliance were observed one year later. Grocery stores had the fewest point of sale promotions displayed at baseline. Compliance rates did not differ across vendor trade classes at either follow-up survey. Point of sale promotions did not differ across regions in any of the three surveys. Within a short period of time, a high level of compliance with six restricted point of sale promotions was achieved.

49 CFR 236.327 - Switch, movable-point frog or split-point derail.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Switch, movable-point frog or split-point derail..., AND APPLIANCES Interlocking Rules and Instructions § 236.327 Switch, movable-point frog or split-point derail. Switch, movable-point frog, or split-point derail equipped with lock rod shall be maintained so...

49 CFR 236.327 - Switch, movable-point frog or split-point derail.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 4 2012-10-01 2012-10-01 false Switch, movable-point frog or split-point derail..., AND APPLIANCES Interlocking Rules and Instructions § 236.327 Switch, movable-point frog or split-point derail. Switch, movable-point frog, or split-point derail equipped with lock rod shall be maintained so...

49 CFR 236.327 - Switch, movable-point frog or split-point derail.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 4 2013-10-01 2013-10-01 false Switch, movable-point frog or split-point derail..., AND APPLIANCES Interlocking Rules and Instructions § 236.327 Switch, movable-point frog or split-point derail. Switch, movable-point frog, or split-point derail equipped with lock rod shall be maintained so...

49 CFR 236.327 - Switch, movable-point frog or split-point derail.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Switch, movable-point frog or split-point derail..., AND APPLIANCES Interlocking Rules and Instructions § 236.327 Switch, movable-point frog or split-point derail. Switch, movable-point frog, or split-point derail equipped with lock rod shall be maintained so...

49 CFR 236.327 - Switch, movable-point frog or split-point derail.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Switch, movable-point frog or split-point derail..., AND APPLIANCES Interlocking Rules and Instructions § 236.327 Switch, movable-point frog or split-point derail. Switch, movable-point frog, or split-point derail equipped with lock rod shall be maintained so...

Impact of a nonuniform charge distribution on virus assembly

NASA Astrophysics Data System (ADS)

Li, Siyu; Erdemci-Tandogan, Gonca; Wagner, Jef; van der Schoot, Paul; Zandi, Roya

2017-08-01

Many spherical viruses encapsulate their genomes in protein shells with icosahedral symmetry. This process is spontaneous and driven by electrostatic interactions between positive domains on the virus coat proteins and the negative genomes. We model the effect of the nonuniform icosahedral charge distribution from the protein shell instead using a mean-field theory. We find that this nonuniform charge distribution strongly affects the optimal genome length and that it can explain the experimentally observed phenomenon of overcharging of virus and viruslike particles.

[Controlled observation of the efficacy between floating acupuncture at Tianying point and warm-needling therapy for supraspinous ligament injury].

PubMed

Li, Xin-Wei; Shao, Xiao-Mei; Tan, Ke-Ping; Fang, Jian-Qiao

2013-04-01

To compare the efficacy difference in the treatment of supraspinous ligament injury between floating acupuncture at Tianying point and the conventional warm needling therapy. Ninety patients were randomized into a floating acupuncture group and a warm needling group, 45 cases in each one. In the floating acupuncture group, the floating needling technique was adopted at Tianying point. In the warm needling group, the conventional warm needling therapy was applied at Tianying point as the chief point in the prescription. The treatment was given 3 times a week and 6 treatments made one session. The visual analogue scale (VAS) was adopted for pain comparison before and after treatment of the patients in two groups and the efficacy in two groups were assessed. The curative and remarkably effective rate was 81.8% (36/44) in the floating acupuncture group and the total effective rate was 95.5% (42/44), which were superior to 44.2% (19/43) and 79.1% (34/43) in the warm needling group separately (P < 0.01, P < 0.05). VAS score was lower as compared with that before treatment of the patients in two groups (both P < 0.01) and the score in the floating acupuncture group was lower than that in the warm needling group after treatment (P < 0.01). Thirty-six cases were cured and remarkably effective in the floating acupuncture group after treatment, in which 28 cases were cured and remarkably effective in 3 treatments, accounting for 77.8 (28/36), which was apparently higher than 26.3 (5/19) in the warm-needling group (P < 0.01). The floating acupuncture at Tianying point achieves the quick and definite efficacy on supraspinous ligament injury and presents the apparent analgesic effect. The efficacy is superior to the conventional warm-needling therapy.

The gallium melting-point standard: its role in our temperature measurement system.

PubMed

Mangum, B W

1977-01-01

The latest internationally-adopted temperature scale, the International Practical Temperature Scale of 1968 (amended edition of 1975), is discussed in some detail and a brief description is given of its evolution. The melting point of high-purity gallium (stated to be at least 99.99999% pure) as a secondary temperature reference point is evaluated. I believe that this melting-point temperature of gallium should be adopted by the various medical professional societies and voluntary standards groups as the reaction temperature for enzyme reference methods in clinical enzymology. Gallium melting-point cells are available at the National Bureau of Standards as Standard Reference Material No. 1968.

47 CFR 73.7003 - Point system selection procedures.

Code of Federal Regulations, 2010 CFR

2010-10-01

... stations. (3) State-wide network. Two points for an applicant that does not qualify for the credit for... the diversity credit and the state-wide network credit in any particular application. (4) Technical... following: (1) If the applicant is in a group for which a “B” cut-off notice issued prior to April 21, 2000...

Spatially-protected Topology and Group Cohomology in Band Insulators

NASA Astrophysics Data System (ADS)

Alexandradinata, A.

This thesis investigates band topologies which rely fundamentally on spatial symmetries. A basic geometric property that distinguishes spatial symmetry regards their transformation of the spatial origin. Point groups consist of spatial transformations that preserve the spatial origin, while un-split extensions of the point groups by spatial translations are referred to as nonsymmorphic space groups. The first part of the thesis addresses topological phases with discretely-robust surface properties: we introduce theories for the Cnv point groups, as well as certain nonsymmorphic groups that involve glide reflections. These band insulators admit a powerful characterization through the geometry of quasimomentum space; parallel transport in this space is represented by the Wilson loop. The non-symmorphic topology we study is naturally described by a further extension of the nonsymmorphic space group by quasimomentum translations (the Wilson loop), thus placing real and quasimomentum space on equal footing -- here, we introduce the language of group cohomology into the theory of band insulators. The second part of the thesis addresses topological phases without surface properties -- their only known physical consequences are discrete signatures in parallel transport. We provide two such case studies with spatial-inversion and discrete-rotational symmetries respectively. One lesson learned here regards the choice of parameter loops in which we carry out transport -- the loop must be chosen to exploit the symmetry that protects the topology. While straight loops are popular for their connection with the geometric theory of polarization, we show that bent loops also have utility in topological band theory.

The Case for Mixed-Age Grouping in Early Education.

ERIC Educational Resources Information Center

Katz, Lilian G.; And Others

In six brief chapters, mixed-age grouping of young children in schools and child care centers is explored and advocated. Chapter 1 defines mixed-age grouping, examines limitations of single-age grouping, and points out positive characteristics of mixed-age classes. Chapter 2 discusses social development as seen in children's interactions in…

Feel like you belong: on the bidirectional link between emotional fit and group identification in task groups

PubMed Central

Delvaux, Ellen; Meeussen, Loes; Mesquita, Batja

2015-01-01

Three studies investigated the association between members’ group identification and the emotional fit with their group. In the first study, a cross-sectional study in a large organization, we replicated earlier research by showing that group identification and emotional fit are positively associated, using a broader range of emotions and using profile correlations to measure group members’ emotional fit. In addition, in two longitudinal studies, where groups of students were followed at several time points during their collaboration on a project, we tested the directionality of the relationship between group identification and emotional fit. The results showed a bidirectional, positive link between group identification and emotional fit, such that group identification and emotional fit either mutually reinforce or mutually dampen each other over time. We discuss how these findings increase insights in group functioning and how they may be used to change group processes for better or worse. PMID:26300806

Structural rigidity in the capsid assembly of cowpea chlorotic mottle virus

NASA Astrophysics Data System (ADS)

Hespenheide, B. M.; Jacobs, D. J.; Thorpe, M. F.

2004-11-01

The cowpea chlorotic mottle virus (CCMV) has a protein cage, or capsid, which encloses its genetic material. The structure of the capsid consists of 180 copies of a single protein that self-assemble inside a cell to form a complete capsid with icosahedral symmetry. The icosahedral surface can be naturally divided into pentagonal and hexagonal faces, and the formation of either of these faces has been proposed to be the first step in the capsid assembly process. We have used the software FIRST to analyse the rigidity of pentameric and hexameric substructures of the complete capsid to explore the viability of certain capsid assembly pathways. FIRST uses the 3D pebble game to determine structural rigidity, and a brief description of this algorithm, as applied to body-bar networks, is given here. We find that the pentameric substructure, which corresponds to a pentagonal face on the icosahedral surface, provides the best structural properties for nucleating the capsid assembly process, consistent with experimental observations.

Morphological evidence for phages in Xylella fastidiosa

PubMed Central

Chen, Jianchi; Civerolo, Edwin L

2008-01-01

Presumptive phage particles associated with Xylella fastidiosa strain Temecula-1 grown in PW broth were observed by transmission electron microscopy (TEM) in ultrathin sections of bacterial cell-containing low speed centrifugation pellets and in partially purified preparations from CsCl equilibrium centrifugation density gradients. Ultrathin-sectioned cell pellets contained icosahedral particles of about 45 nm in diameter. Samples collected from CsCl density gradients revealed mostly non-tailed icosahedral but also tailed particles. The icosahedral particles could be divided into two types: a large type (about 45 nm) and a small type (about 30 nm). Filamentous phage-like particles (17 × 120 to 6,300 nm) were also observed. The presence of different types of phage-like particles resembling to those in several bacteriophage families provides new physical evidence, in addition to X. fastidiosa genomic information, that X. fastidiosa possesses active phages. This is the first report of phage particles released in X. fastidiosa cultures. PMID:18538030

Cooling rate dependence and local structure in aluminum monatomic metallic glass

NASA Astrophysics Data System (ADS)

Kbirou, M.; Trady, S.; Hasnaoui, A.; Mazroui, M.

2017-10-01

The local atomic structure in aluminium monatomic metallic glass is studied using molecular dynamics simulations combined with the embedded atom method (EAM). We have used a variety of analytical methods to characterise the atomic configurations of our system: the Pair Distribution Function (PDF), the Common Neighbour Analysis (CNA) and the Voronoi Tessellation Analysis. CNA was used to investigate the order change from liquid to amorphous phases, recognising that the amount of icosahedral clusters increases with the decrease of temperature. The Voronoi analysis revealed that the icosahedral-like polyhedral are the predominant ones. It has been observed that the PDF function shows a splitting in the second peak, which cannot be attributed to the only ideal icosahedral polyhedron 〈0, 0, 12, 0〉, but also to the formation of other Voronoi polyhedra 〈0, 1, 10, 2〉 . Further, the PDFs were then integrated giving the cumulative coordination number in order to compute the fractal dimension (df).

Observation of a Pharmacist-Conducted Group A Streptococcal Pharyngitis Point-of-Care Test: A Time and Motion Study.

PubMed

Corn, Carolyn E; Klepser, Donald G; Dering-Anderson, Allison M; Brown, Terrence G; Klepser, Michael E; Smith, Jaclyn K

2018-06-01

Acute pharyngitis is among the most common infectious diseases encountered in the United States, resulting in 13 million patient visits annually, with group A streptococcus (GAS) being a common causative pathogen. It is estimated that annual expenditures for the treatment of adult pharyngitis will exceed US$1.2 billion annually. This substantial projection reinforces the need to evaluate diagnosis and treatment of adult pharyngitis in nontraditional settings. The objective of this research is to quantify the amount of pharmacist time required to complete a point-of-care (POC) test for a patient presenting with pharyngitis symptoms. A standardized patient with pharyngitis symptoms visited 11 pharmacies for POC testing services for a total of 33 patient encounters. An observer was present at each encounter and recorded the total encounter time, divided into 9 categories. Pharmacists conducted POC testing in 1 of 2 ways: sequence 1-pharmacists performed all service-related tasks; sequence 2-both pharmacists and pharmacist interns performed service-related tasks. The average time for completion of a POC test for GAS pharyngitis was 25.3 ± 4.8 minutes. The average pharmacist participation time per encounter was 12.7 ± 3.0 minutes (sequence 1), which decreased to 2.6 ± 1.1 minutes when pharmacist interns were involved in the testing (sequence 2). Although additional studies are required to further assess service feasibility, this study indicates that a GAS POC testing service could be implemented in a community pharmacy with limited disruption or change to workflow and staff.

Configuration Analysis of the ERS Points in Large-Volume Metrology System

PubMed Central

Jin, Zhangjun; Yu, Cijun; Li, Jiangxiong; Ke, Yinglin

2015-01-01

In aircraft assembly, multiple laser trackers are used simultaneously to measure large-scale aircraft components. To combine the independent measurements, the transformation matrices between the laser trackers’ coordinate systems and the assembly coordinate system are calculated, by measuring the enhanced referring system (ERS) points. This article aims to understand the influence of the configuration of the ERS points that affect the transformation matrix errors, and then optimize the deployment of the ERS points to reduce the transformation matrix errors. To optimize the deployment of the ERS points, an explicit model is derived to estimate the transformation matrix errors. The estimation model is verified by the experiment implemented in the factory floor. Based on the proposed model, a group of sensitivity coefficients are derived to evaluate the quality of the configuration of the ERS points, and then several typical configurations of the ERS points are analyzed in detail with the sensitivity coefficients. Finally general guidance is established to instruct the deployment of the ERS points in the aspects of the layout, the volume size and the number of the ERS points, as well as the position and orientation of the assembly coordinate system. PMID:26402685

Multiple contacts with diversion at the point of arrest.

PubMed

Riordan, Sharon; Wix, Stuart; Haque, M Sayeed; Humphreys, Martin

2003-04-01

A diversion at the point of arrest (DAPA) scheme was set up in five police stations in South Birmingham in 1992. In a study of all referrals made over a four-year period a sub group of multiple contact individuals was identified. During that time four hundred and ninety-two contacts were recorded in total, of which 130 were made by 58 individuals. The latter group was generally no different from the single contact group but did have a tendency to be younger. This research highlights the need for a re-evaluation of service provision and associated education of police officers and relevant mental health care professionals.

A novel infrared small moving target detection method based on tracking interest points under complicated background

NASA Astrophysics Data System (ADS)

Dong, Xiabin; Huang, Xinsheng; Zheng, Yongbin; Bai, Shengjian; Xu, Wanying

2014-07-01

Infrared moving target detection is an important part of infrared technology. We introduce a novel infrared small moving target detection method based on tracking interest points under complicated background. Firstly, Difference of Gaussians (DOG) filters are used to detect a group of interest points (including the moving targets). Secondly, a sort of small targets tracking method inspired by Human Visual System (HVS) is used to track these interest points for several frames, and then the correlations between interest points in the first frame and the last frame are obtained. Last, a new clustering method named as R-means is proposed to divide these interest points into two groups according to the correlations, one is target points and another is background points. In experimental results, the target-to-clutter ratio (TCR) and the receiver operating characteristics (ROC) curves are computed experimentally to compare the performances of the proposed method and other five sophisticated methods. From the results, the proposed method shows a better discrimination of targets and clutters and has a lower false alarm rate than the existing moving target detection methods.

Draft genome sequence of the Coccolithovirus Emiliania huxleyi virus 203.

PubMed

Nissimov, Jozef I; Worthy, Charlotte A; Rooks, Paul; Napier, Johnathan A; Kimmance, Susan A; Henn, Matthew R; Ogata, Hiroyuki; Allen, Michael J

2011-12-01

The Coccolithoviridae are a recently discovered group of viruses that infect the marine coccolithophorid Emiliania huxleyi. Emiliania huxleyi virus 203 (EhV-203) has a 160- to 180-nm-diameter icosahedral structure and a genome of approximately 400 kbp, consisting of 464 coding sequences (CDSs). Here we describe the genomic features of EhV-203 together with a draft genome sequence and its annotation, highlighting the homology and heterogeneity of this genome in comparison with the EhV-86 reference genome.

Evaluation of 2-point, 3-point, and 6-point Dixon magnetic resonance imaging with flexible echo timing for muscle fat quantification.

PubMed

Grimm, Alexandra; Meyer, Heiko; Nickel, Marcel D; Nittka, Mathias; Raithel, Esther; Chaudry, Oliver; Friedberger, Andreas; Uder, Michael; Kemmler, Wolfgang; Quick, Harald H; Engelke, Klaus

2018-06-01

The purpose of this study is to evaluate and compare 2-point (2pt), 3-point (3pt), and 6-point (6pt) Dixon magnetic resonance imaging (MRI) sequences with flexible echo times (TE) to measure proton density fat fraction (PDFF) within muscles. Two subject groups were recruited (G1: 23 young and healthy men, 31 ± 6 years; G2: 50 elderly men, sarcopenic, 77 ± 5 years). A 3-T MRI system was used to perform Dixon imaging on the left thigh. PDFF was measured with six Dixon prototype sequences: 2pt, 3pt, and 6pt sequences once with optimal TEs (in- and opposed-phase echo times), lower resolution, and higher bandwidth (optTE sequences) and once with higher image resolution (highRes sequences) and shortest possible TE, respectively. Intra-fascia PDFF content was determined. To evaluate the comparability among the sequences, Bland-Altman analysis was performed. The highRes 6pt Dixon sequences served as reference as a high correlation of this sequence to magnetic resonance spectroscopy has been shown before. The PDFF difference between the highRes 6pt Dixon sequence and the optTE 6pt, both 3pt, and the optTE 2pt was low (between 2.2% and 4.4%), however, not to the highRes 2pt Dixon sequence (33%). For the optTE sequences, difference decreased with the number of echoes used. In conclusion, for Dixon sequences with more than two echoes, the fat fraction measurement was reliable with arbitrary echo times, while for 2pt Dixon sequences, it was reliable with dedicated in- and opposed-phase echo timing. Copyright © 2018 Elsevier B.V. All rights reserved.

CUTOFF POINT OF THE PHASE ANGLE IN PRE-RADIOTHERAPY CANCER PATIENTS.

PubMed

Souza Thompson Motta, Rachel; Alves Castanho, Ivany; Guillermo Coca Velarde, Luis

2015-11-01

malnutrition is a common complication for cancer patients. The phase angle (PA), direct measurement of bioelectrical impedance analysis (BIA), has been considered a predictor of body cell mass and prognostic indicator. Cutoff points for phase angle (PA) associated with nutritional risk in cancer patients have not been determined yet. assess the possibility of determining the cutoff point for PA to identify nutritional risk in pre-radiotherapy cancer patients. sample group: Patients from both genders diagnosed with cancer and sent for ambulatory radiotherapy. body mass index (BMI), percentage of weight loss (% WL), mid-arm circumference (MAC), triceps skinfold thickness (TST), mid-arm muscle circumference (MAMC), mid-arm muscle area (MAMA), score and categorical assessment obtained using the Patient-Generated Subjective Global Assessment (PG-SGA) form, PA and standardized phase angle (SPA). Kappa coefficient was used to test the degree of agreement between the diagnoses of nutritional risk obtained from several different methods of nutritional assessment. Cutoff points for the PA through anthropometric indicators and PG-SGA were determined by using Receiver Operating Characteristic (ROC) curves, and patient survival was analyzed with the Cox regression method. the cutoff points with the greatest discriminatory power were those obtained from BMI (5.2) and the categorical assessment of PG-SGA (5.4). The diagnosis obtained using these cutoff points showed a significant association with risk of death for the patients in the sample group. we recommend using the cutoff point 5.2 for the PA as a criterion for identifying nutritional risk in pre-radiotherapy cancer patients. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

Bee venom acupuncture point injection for central post stroke pain: a preliminary single-blind randomized controlled trial.

PubMed

Cho, Seung-Yeon; Park, Joo-Young; Jung, Woo-Sang; Moon, Sang-Kwan; Park, Jung-Mi; Ko, Chang-Nam; Park, Seong-Uk

2013-06-01

We investigated apipuncture, or acupuncture point injection with diluted bee venom, as a promising new treatment for central post stroke pain (CPSP). Bee venom, diluted to 0.005% in normal saline, was administered to the treatment group, and normal saline given to control group as twice-weekly injections for three weeks. The points were LI15, GB21, LI11, GB31, ST36 and GB39 of the affected side and the amount of injection was 0.05 ml at each point. Eight patients in each group were included in the analysis. After three weeks there were significant decreases in visual analogue pain scores compared with baseline in both groups and the treatment group improved more significantly than the control group (p = 0.009). Apipuncture significantly improved CPSP in this pilot trial. Further studies of its mechanisms and a larger and long-term follow-up trial will be needed to determine more definitely the efficacy of apipuncture and to elucidate duration of improvement. Copyright © 2013 Elsevier Ltd. All rights reserved.

Trigger point-related sympathetic nerve activity in chronic sciatic leg pain: a case study.

PubMed

Skorupska, Elżbieta; Rychlik, Michał; Pawelec, Wiktoria; Bednarek, Agata; Samborski, Włodzimierz

2014-10-01

Sciatica has classically been associated with irritation of the sciatic nerve by the vertebral disc and consequent inflammation. Some authors suggest that active trigger points in the gluteus minimus muscle can refer pain in similar way to sciatica. Trigger point diagnosis is based on Travel and Simons criteria, but referred pain and twitch response are significant confirmatory signs of the diagnostic criteria. Although vasoconstriction in the area of a latent trigger point has been demonstrated, the vasomotor reaction of active trigger points has not been examined. We report the case of a 22-year-old Caucasian European man who presented with a 3-year history of chronic sciatic-type leg pain. In the third year of symptoms, coexistent myofascial pain syndrome was diagnosed. Acupuncture needle stimulation of active trigger points under infrared thermovisual camera showed a sudden short-term vasodilatation (an autonomic phenomenon) in the area of referred pain. The vasodilatation spread from 0.2 to 171.9 cm(2) and then gradually decreased. After needling, increases in average and maximum skin temperature were seen as follows: for the thigh, changes were +2.6°C (average) and +3.6°C (maximum); for the calf, changes were +0.9°C (average) and +1.4°C (maximum). It is not yet known whether the vasodilatation observed was evoked exclusively by dry needling of active trigger points. The complex condition of the patient suggests that other variables might have influenced the infrared thermovision camera results. We suggest that it is important to check if vasodilatation in the area of referred pain occurs in all patients with active trigger points. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Equilibrium points of the tilted perfect fluid Bianchi VIh state space

NASA Astrophysics Data System (ADS)

Apostolopoulos, Pantelis S.

2005-05-01

We present the full set of evolution equations for the spatially homogeneous cosmologies of type VIh filled with a tilted perfect fluid and we provide the corresponding equilibrium points of the resulting dynamical state space. It is found that only when the group parameter satisfies h > -1 a self-similar solution exists. In particular we show that for h > -{1/9} there exists a self-similar equilibrium point provided that γ ∈ ({2(3+sqrt{-h})/5+3sqrt{-h}},{3/2}) whereas for h < -{frac 19} the state parameter belongs to the interval γ ∈(1,{2(3+sqrt{-h})/5+3sqrt{-h}}). This family of new exact self-similar solutions belongs to the subclass nαα = 0 having non-zero vorticity. In both cases the equilibrium points have a six-dimensional stable manifold and may act as future attractors at least for the models satisfying nαα = 0. Also we give the exact form of the self-similar metrics in terms of the state and group parameter. As an illustrative example we provide the explicit form of the corresponding self-similar radiation model (γ = {frac 43}), parametrised by the group parameter h. Finally we show that there are no tilted self-similar models of type III and irrotational models of type VIh.

Repelling Point Bosons

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGuire, J. B.

2011-12-01

There is a body of conventional wisdom that holds that a solvable quantum problem, by virtue of its solvability, is pathological and thus irrelevant. It has been difficult to refute this view owing to the paucity of theoretical constructs and experimental results. Recent experiments involving equivalent ions trapped in a spatial conformation of extreme anisotropic confinement (longitudinal extension tens, hundreds or even thousands of times transverse extension) have modified the view of relevancy, and it is now possible to consider systems previously thought pathological, in particular point Bosons that repel in one dimension. It has been difficult for the experimentalistsmore » to utilize existing theory, mainly due to long-standing theoretical misunderstanding of the relevance of the permutation group, in particular the non-commutativity of translations (periodicity) and transpositions (permutation). This misunderstanding is most easily rectified in the case of repelling Bosons.« less

Functional Analytic Psychotherapy for Interpersonal Process Groups: A Behavioral Application

ERIC Educational Resources Information Center

Hoekstra, Renee

2008-01-01

This paper is an adaptation of Kohlenberg and Tsai's work, Functional Analytical Psychotherapy (1991), or FAP, to group psychotherapy. This author applied a behavioral rationale for interpersonal process groups by illustrating key points with a hypothetical client. Suggestions are also provided for starting groups, identifying goals, educating…

Sex Role Consequences: Depends on the Point of View.

ERIC Educational Resources Information Center

Astley, Suzette L.; Downey, Ronald G.

1980-01-01

Self-report measures are positively related to the masculine Bem Sex Role Inventory (BSRI) and are similar for males and females. The BSRI scores are positively related to other group members' evaluations of female leadership performance, but not males. Findings point to the complexities associated with sex-role research. (Author)

46 CFR 7.130 - Point Conception, CA to Point Sur, CA.

Code of Federal Regulations, 2014 CFR

2014-10-01

... LINES Pacific Coast § 7.130 Point Conception, CA to Point Sur, CA. (a) A line drawn from the... 46 Shipping 1 2014-10-01 2014-10-01 false Point Conception, CA to Point Sur, CA. 7.130 Section 7... Breakwater. (b) A line drawn from the outer end of Morro Bay Entrance East Breakwater to latitude 35°21.5′ N...

46 CFR 7.130 - Point Conception, CA to Point Sur, CA.

Code of Federal Regulations, 2011 CFR

2011-10-01

... LINES Pacific Coast § 7.130 Point Conception, CA to Point Sur, CA. (a) A line drawn from the... 46 Shipping 1 2011-10-01 2011-10-01 false Point Conception, CA to Point Sur, CA. 7.130 Section 7... Breakwater. (b) A line drawn from the outer end of Morro Bay Entrance East Breakwater to latitude 35°21.5′ N...

46 CFR 7.125 - Point Vincente, CA to Point Conception, CA.

Code of Federal Regulations, 2010 CFR

2010-10-01

... BOUNDARY LINES Pacific Coast § 7.125 Point Vincente, CA to Point Conception, CA. (a) A line drawn from Redondo Beach East Jetty Light “2” to Redondo Beach West Jetty Light “3”. (b) A line drawn from Marina Del... 46 Shipping 1 2010-10-01 2010-10-01 false Point Vincente, CA to Point Conception, CA. 7.125...

46 CFR 7.130 - Point Conception, CA to Point Sur, CA.

Code of Federal Regulations, 2013 CFR

2013-10-01

... LINES Pacific Coast § 7.130 Point Conception, CA to Point Sur, CA. (a) A line drawn from the... 46 Shipping 1 2013-10-01 2013-10-01 false Point Conception, CA to Point Sur, CA. 7.130 Section 7... Breakwater. (b) A line drawn from the outer end of Morro Bay Entrance East Breakwater to latitude 35°21.5′ N...

46 CFR 7.125 - Point Vincente, CA to Point Conception, CA.

Code of Federal Regulations, 2012 CFR

2012-10-01

... BOUNDARY LINES Pacific Coast § 7.125 Point Vincente, CA to Point Conception, CA. (a) A line drawn from Redondo Beach East Jetty Light “2” to Redondo Beach West Jetty Light “3”. (b) A line drawn from Marina Del... 46 Shipping 1 2012-10-01 2012-10-01 false Point Vincente, CA to Point Conception, CA. 7.125...

46 CFR 7.125 - Point Vincente, CA to Point Conception, CA.

Code of Federal Regulations, 2013 CFR

2013-10-01

... BOUNDARY LINES Pacific Coast § 7.125 Point Vincente, CA to Point Conception, CA. (a) A line drawn from Redondo Beach East Jetty Light “2” to Redondo Beach West Jetty Light “3”. (b) A line drawn from Marina Del... 46 Shipping 1 2013-10-01 2013-10-01 false Point Vincente, CA to Point Conception, CA. 7.125...

46 CFR 7.130 - Point Conception, CA to Point Sur, CA.

Code of Federal Regulations, 2012 CFR

2012-10-01

... LINES Pacific Coast § 7.130 Point Conception, CA to Point Sur, CA. (a) A line drawn from the... 46 Shipping 1 2012-10-01 2012-10-01 false Point Conception, CA to Point Sur, CA. 7.130 Section 7... Breakwater. (b) A line drawn from the outer end of Morro Bay Entrance East Breakwater to latitude 35°21.5′ N...

46 CFR 7.125 - Point Vincente, CA to Point Conception, CA.

Code of Federal Regulations, 2014 CFR

2014-10-01

... BOUNDARY LINES Pacific Coast § 7.125 Point Vincente, CA to Point Conception, CA. (a) A line drawn from Redondo Beach East Jetty Light “2” to Redondo Beach West Jetty Light “3”. (b) A line drawn from Marina Del... 46 Shipping 1 2014-10-01 2014-10-01 false Point Vincente, CA to Point Conception, CA. 7.125...

46 CFR 7.125 - Point Vincente, CA to Point Conception, CA.

Code of Federal Regulations, 2011 CFR

2011-10-01

... BOUNDARY LINES Pacific Coast § 7.125 Point Vincente, CA to Point Conception, CA. (a) A line drawn from Redondo Beach East Jetty Light “2” to Redondo Beach West Jetty Light “3”. (b) A line drawn from Marina Del... 46 Shipping 1 2011-10-01 2011-10-01 false Point Vincente, CA to Point Conception, CA. 7.125...

46 CFR 7.130 - Point Conception, CA to Point Sur, CA.

Code of Federal Regulations, 2010 CFR

2010-10-01

... LINES Pacific Coast § 7.130 Point Conception, CA to Point Sur, CA. (a) A line drawn from the... 46 Shipping 1 2010-10-01 2010-10-01 false Point Conception, CA to Point Sur, CA. 7.130 Section 7... Breakwater. (b) A line drawn from the outer end of Morro Bay Entrance East Breakwater to latitude 35°21.5′ N...

Deviance and dissent in groups.

PubMed

Jetten, Jolanda; Hornsey, Matthew J

2014-01-01

Traditionally, group research has focused more on the motivations that make people conform than on the motivations and conditions underpinning deviance and dissent. This has led to a literature that focuses on the value that groups place on uniformity and paints a relatively dark picture of dissent and deviance: as reflections of a lack of group loyalty, as signs of disengagement, or as delinquent behavior. An alternative point of view, which has gained momentum in recent years, focuses on deviance and dissent as normal and healthy aspects of group life. In this review, we focus on the motivations that group members have to deviate and dissent, and the functional as well as the dysfunctional effects of deviance and dissent. In doing so we aim for a balanced and complete account of deviance and dissent, highlighting when such behaviors will be encouraged as well as when they will be punished.

Band gap scaling laws in group IV nanotubes.

PubMed

Wang, Chongze; Fu, Xiaonan; Guo, Yangyang; Guo, Zhengxiao; Xia, Congxin; Jia, Yu

2017-03-17

By using the first-principles calculations, the band gap properties of nanotubes formed by group IV elements have been investigated systemically. Our results reveal that for armchair nanotubes, the energy gaps at K points in the Brillouin zone decrease as 1/r scaling law with the radii (r) increasing, while they are scaled by -1/r 2  + C at Γ points, here, C is a constant. Further studies show that such scaling law of K points is independent of both the chiral vector and the type of elements. Therefore, the band gaps of nanotubes for a given radius can be determined by these scaling laws easily. Interestingly, we also predict the existence of indirect band gap for both germanium and tin nanotubes. Our new findings provide an efficient way to determine the band gaps of group IV element nanotubes by knowing the radii, as well as to facilitate the design of functional nanodevices.

Problems in understanding the structure and assembly of viruses

DOE Office of Scientific and Technical Information (OSTI.GOV)

King, J.

1997-12-01

Though viruses infect the cells of all groups of animals, plants, and microorganisms, their structures follow a limited number of general themes; spherical or cylindrical shells built of hundreds of repeated protein subunits enclosing a nucleic acid - DNA or RNA - genome. Since the 1960s it has been known that the protein shells of spherical viruses in fact conform to icosahedral symmetry or to subtle deviations from icosahedral symmetry. The construction of the shell lattices and the transformations they go through in the different stages of the viral life cycle are not fully understood. The shells contain the nucleicmore » in a highly condensed state, of unknown coiling/organization. Features of the well studied bacterial viruses will be reviewed, with examples from adenoviruses, herpesviruses, poliovirus, and HIV. The emergence of new viral disease has led to increased interest in the development of agents which interfere with virus reproduction at the level of the assembly or function of the organized particle. Recently computational approaches to the problem of virus assembly have made important contributions to clarifying shell assembly processes. 1 ref.« less

Electrons at the monkey saddle: a multicritical Lifshitz point

NASA Astrophysics Data System (ADS)

Shtyk, Alex; Goldstein, Garry; Chamon, Claudio

We consider 2D interacting electrons at a monkey saddle with dispersion px3 - 3pxpy2 . Such a dispersion naturally arises at the multicritical Lifshitz point when three van Hove saddles merge in an elliptical umbilic elementary catastrophe, which we show can be realized in biased bilayer graphene. A multicritical Lifshitz point of this kind can be identified by its signature Landau level behavior Em (Bm) 3 / 2 and related oscillations in thermodynamic and transport properties, such as de Haas-van Alphen and Shubnikov-de Haas oscillations, whose period triples as the system crosses the singularity. We show, in the case of a single monkey saddle, that the non-interacting electron fixed point is unstable to interactions under the renormalization group flow, developing either a superconducting instability or non-Fermi liquid features. Biased bilayer graphene, where there are two non-nested monkey saddles at the K and K' points, exhibits an interplay of competing many-body instabilities, namely s-wave superconductivity, ferromagnetism, and spin- and charge-density wave. DOE DE-FG02-06ER46316.

Electrons at the monkey saddle: A multicritical Lifshitz point

NASA Astrophysics Data System (ADS)

Shtyk, A.; Goldstein, G.; Chamon, C.

2017-01-01

We consider two-dimensional interacting electrons at a monkey saddle with dispersion ∝px3-3 pxpy2 . Such a dispersion naturally arises at the multicritical Lifshitz point when three Van Hove saddles merge in an elliptical umbilic elementary catastrophe, which we show can be realized in biased bilayer graphene. A multicritical Lifshitz point of this kind can be identified by its signature Landau level behavior Em∝(Bm ) 3 /2 and related oscillations in thermodynamic and transport properties, such as de Haas-Van Alphen and Shubnikov-de Haas oscillations, whose period triples as the system crosses the singularity. We show, in the case of a single monkey saddle, that the noninteracting electron fixed point is unstable to interactions under the renormalization-group flow, developing either a superconducting instability or non-Fermi-liquid features. Biased bilayer graphene, where there are two non-nested monkey saddles at the K and K' points, exhibits an interplay of competing many-body instabilities, namely, s -wave superconductivity, ferromagnetism, and spin- and charge-density waves.

Searches for point sources in the Galactic Center region

NASA Astrophysics Data System (ADS)

di Mauro, Mattia; Fermi-LAT Collaboration

2017-01-01

Several groups have demonstrated the existence of an excess in the gamma-ray emission around the Galactic Center (GC) with respect to the predictions from a variety of Galactic Interstellar Emission Models (GIEMs) and point source catalogs. The origin of this excess, peaked at a few GeV, is still under debate. A possible interpretation is that it comes from a population of unresolved Millisecond Pulsars (MSPs) in the Galactic bulge. We investigate the detection of point sources in the GC region using new tools which the Fermi-LAT Collaboration is developing in the context of searches for Dark Matter (DM) signals. These new tools perform very fast scans iteratively testing for additional point sources at each of the pixels of the region of interest. We show also how to discriminate between point sources and structural residuals from the GIEM. We apply these methods to the GC region considering different GIEMs and testing the DM and MSPs intepretations for the GC excess. Additionally, we create a list of promising MSP candidates that could represent the brightest sources of a MSP bulge population.

Entanglement entropy at infinite-randomness fixed points in higher dimensions.

PubMed

Lin, Yu-Cheng; Iglói, Ferenc; Rieger, Heiko

2007-10-05

The entanglement entropy of the two-dimensional random transverse Ising model is studied with a numerical implementation of the strong-disorder renormalization group. The asymptotic behavior of the entropy per surface area diverges at, and only at, the quantum phase transition that is governed by an infinite-randomness fixed point. Here we identify a double-logarithmic multiplicative correction to the area law for the entanglement entropy. This contrasts with the pure area law valid at the infinite-randomness fixed point in the diluted transverse Ising model in higher dimensions.

Covariant Derivatives and the Renormalization Group Equation

NASA Astrophysics Data System (ADS)

Dolan, Brian P.

The renormalization group equation for N-point correlation functions can be interpreted in a geometrical manner as an equation for Lie transport of amplitudes in the space of couplings. The vector field generating the diffeomorphism has components given by the β functions of the theory. It is argued that this simple picture requires modification whenever any one of the points at which the amplitude is evaluated becomes close to any other. This modification necessitates the introduction of a connection on the space of couplings and new terms appear in the renormalization group equation involving covariant derivatives of the β function and the curvature associated with the connection. It is shown how the connection is related to the operator product expansion coefficients, but there remains an arbitrariness in its definition.

Priming us and them: automatic assimilation and contrast in group attitudes.

PubMed

Ledgerwood, Alison; Chaiken, Shelly

2007-12-01

Social judgment theory holds that a person's own attitudes function as reference points, influencing the perception of others' attitudes. The authors argue that attitudes themselves are influenced by reference points, namely, the presumed attitudes of others. Whereas exposure to a group that acts as a contextual reference should cause attitude assimilation, exposure to a group that acts as a comparative reference should cause attitude contrast. In Study 1, participants subliminally primed with their political ingroup or outgroup endorsed more extreme political positions than did controls. Study 2 demonstrated that prime types known to uniquely facilitate assimilation and contrast enhanced the polarization effect in the ingroup and outgroup conditions, respectively. Study 3 established an important boundary condition for whether group salience produces attitude assimilation or contrast by showing that perceived closeness to the elderly moderates the direction and strength of the group priming effect. The results suggest that the transition from assimilation to contrast occurs when a group ceases to function as a context and becomes a comparison point. Implications for social judgment theory, assimilation and contrast research, and conflict escalation are discussed. (c) 2007 APA, all rights reserved.

Fourth class of convex equilateral polyhedron with polyhedral symmetry related to fullerenes and viruses.

PubMed

Schein, Stan; Gayed, James Maurice

2014-02-25

The three known classes of convex polyhedron with equal edge lengths and polyhedral symmetry--tetrahedral, octahedral, and icosahedral--are the 5 Platonic polyhedra, the 13 Archimedean polyhedra--including the truncated icosahedron or soccer ball--and the 2 rhombic polyhedra reported by Johannes Kepler in 1611. (Some carbon fullerenes, inorganic cages, icosahedral viruses, geodesic structures, and protein complexes resemble these fundamental shapes.) Here we add a fourth class, "Goldberg polyhedra," which are also convex and equilateral. We begin by decorating each of the triangular facets of a tetrahedron, an octahedron, or an icosahedron with the T vertices and connecting edges of a "Goldberg triangle." We obtain the unique set of internal angles in each planar face of each polyhedron by solving a system of n equations and n variables, where the equations set the dihedral angle discrepancy about different types of edge to zero, and the variables are a subset of the internal angles in 6gons. Like the faces in Kepler's rhombic polyhedra, the 6gon faces in Goldberg polyhedra are equilateral and planar but not equiangular. We show that there is just a single tetrahedral Goldberg polyhedron, a single octahedral one, and a systematic, countable infinity of icosahedral ones, one for each Goldberg triangle. Unlike carbon fullerenes and faceted viruses, the icosahedral Goldberg polyhedra are nearly spherical. The reasoning and techniques presented here will enable discovery of still more classes of convex equilateral polyhedra with polyhedral symmetry.

Design of a hyperstable 60-subunit protein icosahedron

NASA Astrophysics Data System (ADS)

Hsia, Yang; Bale, Jacob B.; Gonen, Shane; Shi, Dan; Sheffler, William; Fong, Kimberly K.; Nattermann, Una; Xu, Chunfu; Huang, Po-Ssu; Ravichandran, Rashmi; Yi, Sue; Davis, Trisha N.; Gonen, Tamir; King, Neil P.; Baker, David

2016-07-01

The icosahedron is the largest of the Platonic solids, and icosahedral protein structures are widely used in biological systems for packaging and transport. There has been considerable interest in repurposing such structures for applications ranging from targeted delivery to multivalent immunogen presentation. The ability to design proteins that self-assemble into precisely specified, highly ordered icosahedral structures would open the door to a new generation of protein containers with properties custom-tailored to specific applications. Here we describe the computational design of a 25-nanometre icosahedral nanocage that self-assembles from trimeric protein building blocks. The designed protein was produced in Escherichia coli, and found by electron microscopy to assemble into a homogenous population of icosahedral particles nearly identical to the design model. The particles are stable in 6.7 molar guanidine hydrochloride at up to 80 degrees Celsius, and undergo extremely abrupt, but reversible, disassembly between 2 molar and 2.25 molar guanidinium thiocyanate. The icosahedron is robust to genetic fusions: one or two copies of green fluorescent protein (GFP) can be fused to each of the 60 subunits to create highly fluorescent ‘standard candles’ for use in light microscopy, and a designed protein pentamer can be placed in the centre of each of the 20 pentameric faces to modulate the size of the entrance/exit channels of the cage. Such robust and customizable nanocages should have considerable utility in targeted drug delivery, vaccine design and synthetic biology.

Point-point and point-line moving-window correlation spectroscopy and its applications

NASA Astrophysics Data System (ADS)

Zhou, Qun; Sun, Suqin; Zhan, Daqi; Yu, Zhiwu

2008-07-01

In this paper, we present a new extension of generalized two-dimensional (2D) correlation spectroscopy. Two new algorithms, namely point-point (P-P) correlation and point-line (P-L) correlation, have been introduced to do the moving-window 2D correlation (MW2D) analysis. The new method has been applied to a spectral model consisting of two different processes. The results indicate that P-P correlation spectroscopy can unveil the details and re-constitute the entire process, whilst the P-L can provide general feature of the concerned processes. Phase transition behavior of dimyristoylphosphotidylethanolamine (DMPE) has been studied using MW2D correlation spectroscopy. The newly proposed method verifies that the phase transition temperature is 56 °C, same as the result got from a differential scanning calorimeter. To illustrate the new method further, a lysine and lactose mixture has been studied under thermo perturbation. Using the P-P MW2D, the Maillard reaction of the mixture was clearly monitored, which has been very difficult using conventional display of FTIR spectra.

Electronic shell structure in Ga12 icosahedra and the relation to the bulk forms of gallium.

PubMed

Schebarchov, D; Gaston, N

2012-07-28

The electronic structure of known cluster compounds with a cage-like icosahedral Ga(12) centre is studied by first-principles theoretical methods, based on density functional theory. We consider these hollow metalloid nanostructures in the context of the polymorphism of the bulk, and identify a close relation to the α phase of gallium. This previously unrecognised connection is established using the electron localisation function, which reveals the ubiquitous presence of radially-pointing covalent bonds around the Ga(12) centre--analogous to the covalent bonds between buckled deltahedral planes in α-Ga. Furthermore, we find prominent superatom shell structure in these clusters, despite their hollow icosahedral motif and the presence of covalent bonds. The exact nature of the electronic shell structure is contrasted with simple electron shell models based on jellium, and we demonstrate how the interplay between gallium dimerisation, ligand- and crystal-field effects can alter the splitting of the partially filled 1F shell. Finally, in the unique compound where the Ga(12) centre is bridged by six phosphorus ligands, the electronic structure most closely resembles that of δ-Ga and there are no well-defined superatom orbitals. The results of this comprehensive study bring new insights into the nature of chemical bonding in metalloid gallium compounds and the relation to bulk gallium metal, and they may also guide the development of more general models for ligand-protected clusters.

Improvements in the realization of the ITS-90 over the temperature range from the melting point of gallium to the freezing point of silver at NIM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, J.; Zhang, J. T.; Ping, Q.

2013-09-11

The temperature primary standard over the range from the melting point of gallium to the freezing point of silver in National institute of Metrology (NIM), China, was established in the early 1990s. The performance of all of fixed-point furnaces degraded and needs to be updated due to many years of use. Nowadays, the satisfactory fixed point materials can be available with the development of the modern purification techniques. NIM plans to use a group of three cells for each defining fixed point temperature. In this way the eventual drift of individual cells can be evidenced by periodic intercomparison and thismore » will increase the reliability in disseminating the ITS-90 in China. This article describes the recent improvements in realization of ITS-90 over temperature range from the melting point of gallium to the freezing point of silver at NIM. Taking advantages of the technological advances in the design and manufacture of furnaces, the new three-zone furnaces and the open-type fixed points were developed from the freezing point of indium to the freezing point of silver, and a furnace with the three-zone semiconductor cooling was designed to automatically realize the melting point of gallium. The reproducibility of the new melting point of gallium and the new open-type freezing points of In, Sn, Zn. Al and Ag is improved, especially the freezing points of Al and Ag with the reproducibility of 0.2mK and 0.5mK respectively. The expanded uncertainty in the realization of these defining fixed point temperatures is 0.34mK, 0.44mK, 0.54mK, 0.60mK, 1.30mK and 1.88mK respectively.« less

Update on CERN Search based on SharePoint 2013

NASA Astrophysics Data System (ADS)

Alvarez, E.; Fernandez, S.; Lossent, A.; Posada, I.; Silva, B.; Wagner, A.

2017-10-01

CERN’s enterprise Search solution “CERN Search” provides a central search solution for users and CERN service providers. A total of about 20 million public and protected documents from a wide range of document collections is indexed, including Indico, TWiki, Drupal, SharePoint, JACOW, E-group archives, EDMS, and CERN Web pages. In spring 2015, CERN Search was migrated to a new infrastructure based on SharePoint 2013. In the context of this upgrade, the document pre-processing and indexing process was redesigned and generalised. The new data feeding framework allows to profit from new functionality and it facilitates the long term maintenance of the system.

The effect of different control point sampling sequences on convergence of VMAT inverse planning

NASA Astrophysics Data System (ADS)

Pardo Montero, Juan; Fenwick, John D.

2011-04-01

A key component of some volumetric-modulated arc therapy (VMAT) optimization algorithms is the progressive addition of control points to the optimization. This idea was introduced in Otto's seminal VMAT paper, in which a coarse sampling of control points was used at the beginning of the optimization and new control points were progressively added one at a time. A different form of the methodology is also present in the RapidArc optimizer, which adds new control points in groups called 'multiresolution levels', each doubling the number of control points in the optimization. This progressive sampling accelerates convergence, improving the results obtained, and has similarities with the ordered subset algorithm used to accelerate iterative image reconstruction. In this work we have used a VMAT optimizer developed in-house to study the performance of optimization algorithms which use different control point sampling sequences, most of which fall into three different classes: doubling sequences, which add new control points in groups such that the number of control points in the optimization is (roughly) doubled; Otto-like progressive sampling which adds one control point at a time, and equi-length sequences which contain several multiresolution levels each with the same number of control points. Results are presented in this study for two clinical geometries, prostate and head-and-neck treatments. A dependence of the quality of the final solution on the number of starting control points has been observed, in agreement with previous works. We have found that some sequences, especially E20 and E30 (equi-length sequences with 20 and 30 multiresolution levels, respectively), generate better results than a 5 multiresolution level RapidArc-like sequence. The final value of the cost function is reduced up to 20%, such reductions leading to small improvements in dosimetric parameters characterizing the treatments—slightly more homogeneous target doses and better sparing of

Shifting between Third and First Person Points of View in EFL Narratives

ERIC Educational Resources Information Center

Shokouhi, Hossein; Daram, Mahmood; Sabah, Somayeh

2011-01-01

This article reports on the difference between points of view in narrating a short story. The EFL learners taking part in the control group were required to recount the events from the third person perspective and the subjects in the experimental group from the first person perspective. The methodological frame of the study was based on Koven's…

The Unicellular State as a Point Source in a Quantum Biological System

PubMed Central

Torday, John S.; Miller, William B.

2016-01-01

A point source is the central and most important point or place for any group of cohering phenomena. Evolutionary development presumes that biological processes are sequentially linked, but neither directed from, nor centralized within, any specific biologic structure or stage. However, such an epigenomic entity exists and its transforming effects can be understood through the obligatory recapitulation of all eukaryotic lifeforms through a zygotic unicellular phase. This requisite biological conjunction can now be properly assessed as the focal point of reconciliation between biology and quantum phenomena, illustrated by deconvoluting complex physiologic traits back to their unicellular origins. PMID:27240413

Academic and Personal Development through Group Work: An Exploratory Study

ERIC Educational Resources Information Center

Steen, Sam

2011-01-01

This exploratory study linked academic and personal development within a group counseling intervention. A pre-test post-test research design compared social skills, learning behaviors, and achievement with a convenience sample and control group of students from three elementary schools. For the treatment group, grade point average in Language Arts…

Internal character dictates transition dynamics between isolation and cohesive grouping

NASA Astrophysics Data System (ADS)

Manrique, Pedro D.; Hui, Pak Ming; Johnson, Neil F.

2015-12-01

We show that accounting for internal character among interacting heterogeneous entities generates rich transition behavior between isolation and cohesive dynamical grouping. Our analytical and numerical calculations reveal different critical points arising for different character-dependent grouping mechanisms. These critical points move in opposite directions as the population's diversity decreases. Our analytical theory may help explain why a particular class of universality is so common in the real world, despite the fundamental differences in the underlying entities. It also correctly predicts the nonmonotonic temporal variation in connectivity observed recently in one such system.

Infrared fixed point of SU(2) gauge theory with six flavors

NASA Astrophysics Data System (ADS)

Leino, Viljami; Rummukainen, Kari; Suorsa, Joni; Tuominen, Kimmo; Tähtinen, Sara

2018-06-01

We compute the running of the coupling in SU(2) gauge theory with six fermions in the fundamental representation of the gauge group. We find strong evidence that this theory has an infrared stable fixed point at strong coupling and measure also the anomalous dimension of the fermion mass operator at the fixed point. This theory therefore likely lies close to the boundary of the conformal window and will display novel infrared dynamics if coupled with the electroweak sector of the Standard Model.

Work characteristics and determinants of job satisfaction in four age groups: university employees' point of view.

PubMed

Bos, Judith T; Donders, Nathalie C G M; Bouwman-Brouwer, Karin M; Van der Gulden, Joost W J

2009-11-01

To investigate (a) differences in work characteristics and (b) determinants of job satisfaction among employees in different age groups. A cross-sectional questionnaire was filled in by 1,112 university employees, classified into four age groups. (a) Work characteristics were analysed with ANOVA while adjusting for sex and job classification. (b) Job satisfaction was regressed against job demands and job resources adapted from the Job Demands-Resources model. Statistically significant differences concerning work characteristics between age groups are present, but rather small. Regression analyses revealed that negative association of the job demands workload and conflicts at work with job satisfaction faded by adding job resources. Job resources were most correlated with more job satisfaction, especially more skill discretion and more relations with colleagues. Skill discretion and relations with colleagues are major determinants of job satisfaction. However, attention should also be given to conflicts at work, support from supervisor and opportunities for further education, because the mean scores of these work characteristics were disappointing in almost all age groups. The latter two characteristics were found to be associated significantly to job satisfaction in older workers.

SPS antenna pointing control

NASA Technical Reports Server (NTRS)

Hung, J. C.

1980-01-01

The pointing control of a microwave antenna of the Satellite Power System was investigated emphasizing: (1) the SPS antenna pointing error sensing method; (2) a rigid body pointing control design; and (3) approaches for modeling the flexible body characteristics of the solar collector. Accuracy requirements for the antenna pointing control consist of a mechanical pointing control accuracy of three arc-minutes and an electronic phased array pointing accuracy of three arc-seconds. Results based on the factors considered in current analysis, show that the three arc-minute overall pointing control accuracy can be achieved in practice.

Towards 3D Matching of Point Clouds Derived from Oblique and Nadir Airborne Imagery

NASA Astrophysics Data System (ADS)

Zhang, Ming

Because of the low-expense high-efficient image collection process and the rich 3D and texture information presented in the images, a combined use of 2D airborne nadir and oblique images to reconstruct 3D geometric scene has a promising market for future commercial usage like urban planning or first responders. The methodology introduced in this thesis provides a feasible way towards fully automated 3D city modeling from oblique and nadir airborne imagery. In this thesis, the difficulty of matching 2D images with large disparity is avoided by grouping the images first and applying the 3D registration afterward. The procedure starts with the extraction of point clouds using a modified version of the RIT 3D Extraction Workflow. Then the point clouds are refined by noise removal and surface smoothing processes. Since the point clouds extracted from different image groups use independent coordinate systems, there are translation, rotation and scale differences existing. To figure out these differences, 3D keypoints and their features are extracted. For each pair of point clouds, an initial alignment and a more accurate registration are applied in succession. The final transform matrix presents the parameters describing the translation, rotation and scale requirements. The methodology presented in the thesis has been shown to behave well for test data. The robustness of this method is discussed by adding artificial noise to the test data. For Pictometry oblique aerial imagery, the initial alignment provides a rough alignment result, which contains a larger offset compared to that of test data because of the low quality of the point clouds themselves, but it can be further refined through the final optimization. The accuracy of the final registration result is evaluated by comparing it to the result obtained from manual selection of matched points. Using the method introduced, point clouds extracted from different image groups could be combined with each other to build a

Draft genome sequence of the coccolithovirus Emiliania huxleyi virus 202.

PubMed

Nissimov, Jozef I; Worthy, Charlotte A; Rooks, Paul; Napier, Johnathan A; Kimmance, Susan A; Henn, Matthew R; Ogata, Hiroyuki; Allen, Michael J

2012-02-01

Emiliania huxleyi virus 202 (EhV-202) is a member of the Coccolithoviridae, a group of viruses that infect the marine coccolithophorid Emiliania huxleyi. EhV-202 has a 160- to 180-nm-diameter icosahedral structure and a genome of approximately 407 kbp, consisting of 485 coding sequences (CDSs). Here we describe the genomic features of EhV-202, together with a draft genome sequence and its annotation, highlighting the homology and heterogeneity of this genome in comparison with the EhV-86 reference genome.

Integrating the ACR Appropriateness Criteria Into the Radiology Clerkship: Comparison of Didactic Format and Group-Based Learning.

PubMed

Stein, Marjorie W; Frank, Susan J; Roberts, Jeffrey H; Finkelstein, Malka; Heo, Moonseong

2016-05-01

The aim of this study was to determine whether group-based or didactic teaching is more effective to teach ACR Appropriateness Criteria to medical students. An identical pretest, posttest, and delayed multiple-choice test was used to evaluate the efficacy of the two teaching methods. Descriptive statistics comparing test scores were obtained. On the posttest, the didactic group gained 12.5 points (P < .0001), and the group-based learning students gained 16.3 points (P < .0001). On the delayed test, the didactic group gained 14.4 points (P < .0001), and the group-based learning students gained 11.8 points (P < .001). The gains in scores on both tests were statistically significant for both groups. However, the differences in scores were not statistically significant comparing the two educational methods. Compared with didactic lectures, group-based learning is more enjoyable, time efficient, and equally efficacious. The choice of educational method can be individualized for each institution on the basis of group size, time constraints, and faculty availability. Copyright © 2016 American College of Radiology. Published by Elsevier Inc. All rights reserved.

GOLD Stage and Treatment in COPD: A 500 Patient Point Prevalence Study.

PubMed

Safka, Katherine A; Wald, Joshua; Wang, Hongyu; McIvor, Luke; McIvor, Andrew

2016-12-22

Background and Objective: The Global initiative for chronic Obstructive Lung Disease (GOLD) guidelines recommend using a combination of spirometry, symptoms and exacerbation history to classify patients into 4 categories (A, B, C, D) to guide treatment decisions along with a stepwise increase in therapy. Our objectives were to identify the GOLD stage of patients in respiratory outpatient clinics and assess how treatment compares to guideline recommendations. Methods: This was a point prevalence study using a convenience sample of 500 patients with chronic obstructive pulmonary disease (COPD) from a single tertiary care outpatient respiratory clinic. Results: Patients' GOLD classification was determined based on symptoms (modified Medical Research Council [mMRC] dyspnea scale, COPD Assessment Test [CAT]), spirometry and self-reported exacerbation history. A total of 8.2% of patients were in the GOLD group A, 28.3% in group B, 4.2% in group C and 59.2% in group D. Conclusions: In this 500 patient point prevalence study we report a low proportion of patients in GOLD group C and a high level of inhaled corticosteroids (ICS)/ long-acting beta2-agonist (LABA) and triple therapy use throughout all GOLD categories. Clinical Implications: The GOLD guidelines have attempted to provide direction to practitioners by grouping patients into 4 groups based on symptoms and exacerbations however, the low prevalence of GOLD group C may indicate that not all of these groupings are clinically relevant. Future research is needed to better identify clinically relevant phenotypes that predict benefit from ICS and methods to promote guideline concordant management in COPD.

Light Stops at Exceptional Points

NASA Astrophysics Data System (ADS)

Goldzak, Tamar; Mailybaev, Alexei A.; Moiseyev, Nimrod

2018-01-01

Almost twenty years ago, light was slowed down to less than 10-7 of its vacuum speed in a cloud of ultracold atoms of sodium. Upon a sudden turn-off of the coupling laser, a slow light pulse can be imprinted on cold atoms such that it can be read out and converted into a photon again. In this process, the light is stopped by absorbing it and storing its shape within the atomic ensemble. Alternatively, the light can be stopped at the band edge in photonic-crystal waveguides, where the group speed vanishes. Here, we extend the phenomenon of stopped light to the new field of parity-time (P T ) symmetric systems. We show that zero group speed in P T symmetric optical waveguides can be achieved if the system is prepared at an exceptional point, where two optical modes coalesce. This effect can be tuned for optical pulses in a wide range of frequencies and bandwidths, as we demonstrate in a system of coupled waveguides with gain and loss.

[Acupuncture combined with auricular point sticking therapy for post stroke depression:a randomized controlled trial].

PubMed

Zhang, Lin; Zhong, Yan; Quan, Shulin; Liu, Yehui; Shi, Xuehui; Li, Zhenguang; Wang, Jingjing

2017-06-12

To observe the clinical effects of acupuncture combined with auricular point sticking based on the western medication for post stroke depression (PSD). Sixty patients with PSD were randomly assigned into an acupuncture plus auricular application group (a combination group) and a medication group, 30 cases in each one. 20 mg paroxetine hydrochloride was prescribed orally in the medication group, once a day for continuous 8 weeks. Based on the above treatment, 30-minute acupuncture was used in the combination group for 8 weeks at Baihui (GV 20), Sishencong (EX-HN 1), Shenting (GV 24), Yintang (GV 29), Shenmen (HT 7), Neiguan (PC 6), Taichong (LR 3), Hegu (LI 4), Zusanli (ST 36), Sanyinjiao (SP 6) and Fenglong (ST 40), once the other day and three times a week. Auricular point sticking therapy for 8 weeks was applied at shenmen (TF 4 ), pizhixia (AT 4 ), xin (CO 15 ), and gan (CO 12 ), with pressing 3 times a day and once 3-5 days. The total score and each factor scores of Hamilton's depression scale (HAMD) were observed in the two groups before and after treatment, and Asberg's antidepressant side-effect rating scale (SERS) and clinical effect were evaluated. After treatment, the total HAMD scores of the two groups decreased compared with those before treatment (both P <0.05), with better effect in the combination group ( P <0.05). The scores of the combination group after treatment were lower than those in the medication group, including the anxiety/somatization factor, sleep disturbance factor, hopelessness factor (all P <0.05). The total effective rate of the combination group was 86.7% (26/30), which was better than 66.7% (20/30) of the medication group ( P <0.05). The SERS score of the combination group was lower than that of the medication group ( P <0.05). Acupuncture combined with auricular point sticking can improve the clinical symptoms and are effective and safe for PSD.

Quantum coordinated multi-point communication based on entanglement swapping

NASA Astrophysics Data System (ADS)

Du, Gang; Shang, Tao; Liu, Jian-wei

2017-05-01

In a quantum network, adjacent nodes can communicate with each other point to point by using pre-shared Einsten-Podolsky-Rosen (EPR) pairs, and furthermore remote nodes can establish entanglement channels by using quantum routing among intermediate nodes. However, with the rapid development of quantum networks, the demand of various message transmission among nodes inevitably emerges. In order to realize this goal and extend quantum networks, we propose a quantum coordinated multi-point communication scheme based on entanglement swapping. The scheme takes full advantage of EPR pairs between adjacent nodes and performs multi-party entanglement swapping to transmit messages. Considering various demands of communication, all nodes work cooperatively to realize different message transmission modes, including one to many, many to one and one to some. Scheme analysis shows that the proposed scheme can flexibly organize a coordinated group and efficiently use EPR resources, while it meets basic security requirement under the condition of coordinated communication.

Renormalization group naturalness of GUT Higgs potentials

NASA Astrophysics Data System (ADS)

Allanach, B. C.; Amelino-Camelia, G.; Philipsen, O.; Pisanti, O.; Rosa, L.

1999-01-01

We analyze the symmetry-breaking patterns of grand unified theories from the point of view of a recently proposed criterion of renormalization-group naturalness. We perform the analysis on simple non-SUSY SU(5) and SO(10) and SUSY SU(5) GUTs. We find that the naturalness criterion can favor spontaneous symmetry breaking in the direction of the smallest of the maximal little groups. Some differences between theories with and without supersymmetry are also emphasized.

Investigating Clinically and Scientifically Useful Cut Points on the Compulsive Sexual Behavior Inventory

PubMed Central

Miner, Michael H.; Raymond, Nancy; Coleman, Eli; Romine, Rebecca Swinburne

2017-01-01

Introduction One of the major obstacles to conducting epidemiological research and determining the incidence and prevalence of compulsive sexual behavior has been the lack of relevant, empirically derived cut points on the various instruments that have been used to measure the concept. Aim To further develop the Compulsive Sexual Behavior Inventory (CSBI) through exploring predictive validity and developing an empirically determined and clinically useful cut point for defining CSB. Methods A sample of 242 men who have sex with men was recruited from various sites in a moderate-size Midwestern city. Participants were assigned to a CSB group or a control group using an interview for the diagnosis that was patterned after the Structured Clinical Interview for the Diagnostic and Statistical Manual for Mental Disorders, Fourth Edition. The 22-item CSBI was administered as part of a larger battery of self-report inventories. Main Outcome Measures ROC analyses were used to compute AUC measures to ascertain predictive validity of the total scale, the control subscale and the violence subscale. Cut-points were determined through consensus of experts balancing sensitivity and specificity as determined by ROC curves. Results Analyses indicated that the 22-item CSBI was a good predictor of group membership, as was the 13-item control subscale. The Violence subscale added little to the predictive accuracy of the instrument and thus, it likely measures something other than CSB. Two relevant cut points were found, one that minimized false negatives and another, more conservative cut-point that minimized false positives. Conclusion The CSBI as currently configured measures two different constructions and only the Control subscale is helpful in diagnosing CSB. We have, therefore, decided to eliminate the Violence subscale and move forward with a 13-item scale that we have named the CSBI-13. Two cut points were developed from this revised scale, one which is useful as a clinical

Operation PLUMBBOB. Summary Report, Test Group 57, Nevada Test Site. Extracted Version

DTIC Science & Technology

1982-06-04

numnber) Operation PI*;UMBDOo lest Group 57 conducted a one- point detonation for the purpose of studying hazards from acci- dents. The objectives were...I ! i - 5-6 ABSTRACT On April 24, 1957, Operation Plumbbob Test Group 57 conducted a one- point detonation Ifor the purpose of studying...Plot of Air Sampler Array. 54 4.5 Staplex Air Sampler With Adapter Head . 55 4. 6 Staplex Air Sampler With Annular Impactor 56 13 ILLUSTRATIONS

Point specificity in acupuncture

PubMed Central

2012-01-01

The existence of point specificity in acupuncture is controversial, because many acupuncture studies using this principle to select control points have found that sham acupoints have similar effects to those of verum acupoints. Furthermore, the results of pain-related studies based on visual analogue scales have not supported the concept of point specificity. In contrast, hemodynamic, functional magnetic resonance imaging and neurophysiological studies evaluating the responses to stimulation of multiple points on the body surface have shown that point-specific actions are present. This review article focuses on clinical and laboratory studies supporting the existence of point specificity in acupuncture and also addresses studies that do not support this concept. Further research is needed to elucidate the point-specific actions of acupuncture. PMID:22373514

Investigating Clinically and Scientifically Useful Cut Points on the Compulsive Sexual Behavior Inventory.

PubMed

Miner, Michael H; Raymond, Nancy; Coleman, Eli; Swinburne Romine, Rebecca

2017-05-01

One of the major obstacles to conducting epidemiologic research and determining the incidence and prevalence of compulsive sexual behavior (CSB) has been the lack of relevant empirically derived cut points on the various instruments that have been used to measure the concept. To further develop the Compulsive Sexual Behavior Inventory (CSBI) through exploring predictive validity and developing an empirically determined and clinically useful cut point for defining CSB. A sample of 242 men who have sex with men was recruited from various sites in a moderate-size Midwestern city. Participants were assigned to a CSB group or a control group using an interview for the diagnosis that was patterned after the Structured Clinical Interview for the Diagnostic and Statistical Manual for Mental Disorders, Fourth Edition. The 22-item CSBI was administered as part of a larger battery of self-report inventories. Receiver operating characteristic analyses were used to compute area-under-the-curve measurements to ascertain the predictive validity of the total scale, the control subscale, and the violence subscale. Cut points were determined through consensus of experts balancing sensitivity and specificity as determined by receiver operating characteristic curves. Analyses indicated that the 22-item CSBI was a good predictor of group membership, as was the 13-item control subscale. The violence subscale added little to the predictive accuracy of the instrument; thus, it likely measures something other than CSB. Two relevant cut points were found, one that minimized false negatives and another, more conservative cut point that minimized false positives. The CSBI as currently configured measures two different constructions and only the control subscale is helpful in diagnosing CSB. Therefore, we decided to eliminate the violence subscale and move forward with a 13-item scale that we have named the CSBI-13. Two cut points were developed from this revised scale, one that is useful as a

Redshift differences of galaxies in nearby groups

NASA Technical Reports Server (NTRS)

Harrison, E. R.

1975-01-01

It is reported that galaxies in nearby groups exhibit anomalous nonvelocity redshifts. In this discussion, (1) four classes of nearby groups of galacies are analyzed, and no significant nonvelocity redshift effect is found; and (2) it is pointed out that transverse velocities (i.e., velocities transverse to the line of sight of the main galaxy, or center of mass) contribute components to the redshift measurements of companion galaxies. The redshifts of galaxies in nearby groups of appreciable angular size are considerably affected by these velocity projection effects. The transverse velocity contributions average out in rich, isotropic groups, and also in large samples of irregular groups of low membership, as in the four classes referred to in (1), but can introduce apparent discrepancies in small samples (as studied by Arp) of nearby groups of low membership.

Experimental determination of group flux control coefficients in metabolic networks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simpson, T.W.; Shimizu, Hiroshi; Stephanopoulos, G.

1998-04-20

Grouping of reactions around key metabolite branch points can facilitate the study of metabolic control of complex metabolic networks. This top-down Metabolic Control Analysis is exemplified through the introduction of group control coefficients whose magnitudes provide a measure of the relative impact of each reaction group on the overall network flux, as well as on the overall network stability, following enzymatic amplification. In this article, the authors demonstrate the application of previously developed theory to the determination of group flux control coefficients. Experimental data for the changes in metabolic fluxes obtained in response to the introduction of six different environmentalmore » perturbations are used to determine the group flux control coefficients for three reaction groups formed around the phosphoenolpyruvate/pyruvate branch point. The consistency of the obtained group flux control coefficient estimates is systematically analyzed to ensure that all necessary conditions are satisfied. The magnitudes of the determined control coefficients suggest that the control of lysine production flux in Corynebacterium glutamicum cells at a growth base state resides within the lysine biosynthetic pathway that begins with the PEP/PYR carboxylation anaplorotic pathway.« less

Symmetrical group theory for mathematical complexity reduction of digital holograms

NASA Astrophysics Data System (ADS)

Perez-Ramirez, A.; Guerrero-Juk, J.; Sanchez-Lara, R.; Perez-Ramirez, M.; Rodriguez-Blanco, M. A.; May-Alarcon, M.

2017-10-01

This work presents the use of mathematical group theory through an algorithm to reduce the multiplicative computational complexity in the process of creating digital holograms. An object is considered as a set of point sources using mathematical symmetry properties of both the core in the Fresnel integral and the image, where the image is modeled using group theory. This algorithm has multiplicative complexity equal to zero and an additive complexity ( k - 1) × N for the case of sparse matrices and binary images, where k is the number of pixels other than zero and N is the total points in the image.

Cardiorenal end points in a trial of aliskiren for type 2 diabetes.

PubMed

Parving, Hans-Henrik; Brenner, Barry M; McMurray, John J V; de Zeeuw, Dick; Haffner, Steven M; Solomon, Scott D; Chaturvedi, Nish; Persson, Frederik; Desai, Akshay S; Nicolaides, Maria; Richard, Alexia; Xiang, Zhihua; Brunel, Patrick; Pfeffer, Marc A

2012-12-06

This study was undertaken to determine whether use of the direct renin inhibitor aliskiren would reduce cardiovascular and renal events in patients with type 2 diabetes and chronic kidney disease, cardiovascular disease, or both. In a double-blind fashion, we randomly assigned 8561 patients to aliskiren (300 mg daily) or placebo as an adjunct to an angiotensin-converting-enzyme inhibitor or an angiotensin-receptor blocker. The primary end point was a composite of the time to cardiovascular death or a first occurrence of cardiac arrest with resuscitation; nonfatal myocardial infarction; nonfatal stroke; unplanned hospitalization for heart failure; end-stage renal disease, death attributable to kidney failure, or the need for renal-replacement therapy with no dialysis or transplantation available or initiated; or doubling of the baseline serum creatinine level. The trial was stopped prematurely after the second interim efficacy analysis. After a median follow-up of 32.9 months, the primary end point had occurred in 783 patients (18.3%) assigned to aliskiren as compared with 732 (17.1%) assigned to placebo (hazard ratio, 1.08; 95% confidence interval [CI], 0.98 to 1.20; P=0.12). Effects on secondary renal end points were similar. Systolic and diastolic blood pressures were lower with aliskiren (between-group differences, 1.3 and 0.6 mm Hg, respectively) and the mean reduction in the urinary albumin-to-creatinine ratio was greater (between-group difference, 14 percentage points; 95% CI, 11 to 17). The proportion of patients with hyperkalemia (serum potassium level, ≥6 mmol per liter) was significantly higher in the aliskiren group than in the placebo group (11.2% vs. 7.2%), as was the proportion with reported hypotension (12.1% vs. 8.3%) (P<0.001 for both comparisons). The addition of aliskiren to standard therapy with renin-angiotensin system blockade in patients with type 2 diabetes who are at high risk for cardiovascular and renal events is not supported by these

Is There an Association Between Lumbosacral Radiculopathy and Painful Gluteal Trigger Points?: A Cross-sectional Study.

PubMed

Adelmanesh, Farhad; Jalali, Ali; Jazayeri Shooshtari, Seyed Mostafa; Raissi, Gholam Reza; Ketabchi, Seyed Mehdi; Shir, Yoram

2015-10-01

The objective of this study was to compare the prevalence of gluteal trigger point in patients with lumbosacral radiculopathy with that in healthy volunteers. In a cross-sectional, multistage sampling method, patients with clinical, electromyographic, and magnetic resonance imaging findings consistent with lumbosacral radiculopathy were examined for the presence of gluteal trigger point. Age- and sex-matched clusters of healthy volunteers were selected as the control group. The primary outcome of the study was the presence or absence of gluteal trigger point in the gluteal region of the patients and the control group. Of 441 screened patients, 271 met all the inclusion criteria for lumbosacral radiculopathy and were included in the study. Gluteal trigger point was identified in 207 (76.4%) of the 271 patients with radiculopathy, compared with 3 (1.9%) of 152 healthy volunteers (P < 0.001). The location of gluteal trigger point matched the side of painful radiculopathy in 74.6% of patients with a unilateral radicular pain. There was a significant correlation between the side of the gluteal trigger point and the side of patients' radicular pain (P < 0.001). Although rare in the healthy volunteers, most of the patients with lumbosacral radiculopathy had gluteal trigger point, located at the painful side. Further studies are required to test the hypothesis that specific gluteal trigger point therapy could be beneficial in these patients.

Physically detached 'compact groups'

NASA Technical Reports Server (NTRS)

Hernquist, Lars; Katz, Neal; Weinberg, David H.

1995-01-01

A small fraction of galaxies appear to reside in dense compact groups, whose inferred crossing times are much shorter than a Hubble time. These short crossing times have led to considerable disagreement among researchers attempting to deduce the dynamical state of these systems. In this paper, we suggest that many of the observed groups are not physically bound but are chance projections of galaxies well separated along the line of sight. Unlike earlier similar proposals, ours does not require that the galaxies in the compact group be members of a more diffuse, but physically bound entity. The probability of physically separated galaxies projecting into an apparent compact group is nonnegligible if most galaxies are distributed in thin filaments. We illustrate this general point with a specific example: a simulation of a cold dark matter universe, in which hydrodynamic effects are included to identify galaxies. The simulated galaxy distribution is filamentary and end-on views of these filaments produce apparent galaxy associations that have sizes and velocity dispersions similar to those of observed compact groups. The frequency of such projections is sufficient, in principle, to explain the observed space density of groups in the Hickson catalog. We discuss the implications of our proposal for the formation and evolution of groups and elliptical galaxies. The proposal can be tested by using redshift-independent distance estimators to measure the line-of-sight spatial extent of nearby compact groups.

Neuro Emotional Technique for the treatment of trigger point sensitivity in chronic neck pain sufferers: A controlled clinical trial

PubMed Central

Bablis, Peter; Pollard, Henry; Bonello, Rod

2008-01-01

Background Trigger points have been shown to be active in many myofascial pain syndromes. Treatment of trigger point pain and dysfunction may be explained through the mechanisms of central and peripheral paradigms. This study aimed to investigate whether the mind/body treatment of Neuro Emotional Technique (NET) could significantly relieve pain sensitivity of trigger points presenting in a cohort of chronic neck pain sufferers. Methods Sixty participants presenting to a private chiropractic clinic with chronic cervical pain as their primary complaint were sequentially allocated into treatment and control groups. Participants in the treatment group received a short course of Neuro Emotional Technique that consists of muscle testing, general semantics and Traditional Chinese Medicine. The control group received a sham NET protocol. Outcome measurements included pain assessment utilizing a visual analog scale and a pressure gauge algometer. Pain sensitivity was measured at four trigger point locations: suboccipital region (S); levator scapulae region (LS); sternocleidomastoid region (SCM) and temporomandibular region (TMJ). For each outcome measurement and each trigger point, we calculated the change in measurement between pre- and post- treatment. We then examined the relationships between these measurement changes and six independent variables (i.e. treatment group and the above five additional participant variables) using forward stepwise General Linear Model. Results The visual analog scale (0 to 10) had an improvement of 7.6 at S, 7.2 at LS, 7.5 at SCM and 7.1 at the TMJ in the treatment group compared with no improvement of at S, and an improvement of 0.04 at LS, 0.1 at SCM and 0.1 at the TMJ point in the control group, (P < 0.001). Conclusion After a short course of NET treatment, measurements of visual analog scale and pressure algometer recordings of four trigger point locations in a cohort of chronic neck pain sufferers were significantly improved when

Complementary and alternative therapies to relieve labor pain: A comparative study between music therapy and Hoku point ice massage.

PubMed

Dehcheshmeh, Faranak Safdari; Rafiei, Hossein

2015-11-01

Pain is a common experience for women during labor. In the present study, we compared the effect of two types of non-pharmacological pain relief methods "music therapy" and "Hoku point ice massage" on the severity of labor pain. This prospective, randomized, controlled trial was conducted in Shahrekord, Iran, from September 2013 to June 2014. We randomly assigned 90 primiparous women who expected a normal childbirth into three groups: group "A" received music therapy, group "B" received Hoku point ice massage, and group "C" received usual labor care. At the beginning of the active phase (4 cm cervical dilation) and before and after each intervention (at dilations 4, 6, and 8 cm), the intensities of labor pain were measured using Visual Analogue Scale (VAS). At the beginning of the active phase, the mean VAS scores were 5.58 ± 1.29, 5.42 ± 1.31, and 6.13 ± 1.37 in the women in groups "A," "B," and "C," respectively (P > 0.05). After the intervention, the mean pain scores were significantly lower at all of the time points in groups "A" and "B" than in group "C" women (P < 0.05). Although the pain scores showed a more decreasing trend after the intervention in group "A" than that in group "B," the difference between the two groups was not statistically significant (P > 0.05). Music therapy and Hoku point ice massage are easily available and inexpensive methods and have a similar effect in relieving labor pain. Copyright © 2015 Elsevier Ltd. All rights reserved.

Frontal lobe morphometry with MRI in a normal age group of 6-17 year-olds.

PubMed

Ilkay Koşar, M; Otağ, Ilhan; Sabancıoğulları, Vedat; Atalar, Mehmet; Tetiker, Hasan; Otağ, Aynur; Cimen, Mehmet

2012-12-01

Morphometric data of the frontal lobe are important for surgical planning of lesions in the frontal lobe and its surroundings. Magnetic resonance imaging (MRI) techniques provide suitable data for this purpose. In our study, the morphometric data of mid-sagittal MRI of the frontal lobe in certain age and gender groups of children have been presented. In a normal age group of 6-17-year-old participants, the length of the line passing through predetermined different points, including the frontal pole (FP), commissura anterior (AC), commissura posterior (PC), the outermost point of corpus callosum genu (AGCC), the innermost point of corpus callosum genu (IGCC), tuberculum sella (TS), AGCC and IGCC points parallel to AC-PC line and the point such line crosses at the frontal lobe surface (FCS) were measured in three age groups (6-9, 10-13 and 14-17 years) for each gender. The frontal lobe morphometric data were higher in males than females. Frontal lobe measurements peak at the age group of 10-13 in the male and at the age group of 6-13 in the female. In boys, the length of FP-AC increases 4.1% in the 10-13 age group compared with the 6-9-year-old group, while this increase is 2.3% in girls. Differences in age and gender groups were determined. While the length of AGCC-IGCC increases 10.4% in adults, in children aged 6-17, the length of AC-PC is 11.5% greater than adults. These data will contribute to the preliminary assessment for developing a surgical plan in fine interventions in the frontal lobe and its surroundings in children.

Magazine Picture Collage in Group Supervision

ERIC Educational Resources Information Center

Shepard, Blythe C.; Guenette, Francis L.

2010-01-01

A magazine picture collage activity was used with three female counsellor education students as a vehicle to support them in processing their experience as counsellors in training. The use of magazine picture collage in group supervision is described, and the benefits and challenges are presented. The collages served as jumping-off points for…

Temporally-Constrained Group Sparse Learning for Longitudinal Data Analysis in Alzheimer’s Disease

PubMed Central

Jie, Biao; Liu, Mingxia; Liu, Jun

2016-01-01

Sparse learning has been widely investigated for analysis of brain images to assist the diagnosis of Alzheimer’s disease (AD) and its prodromal stage, i.e., mild cognitive impairment (MCI). However, most existing sparse learning-based studies only adopt cross-sectional analysis methods, where the sparse model is learned using data from a single time-point. Actually, multiple time-points of data are often available in brain imaging applications, which can be used in some longitudinal analysis methods to better uncover the disease progression patterns. Accordingly, in this paper we propose a novel temporally-constrained group sparse learning method aiming for longitudinal analysis with multiple time-points of data. Specifically, we learn a sparse linear regression model by using the imaging data from multiple time-points, where a group regularization term is first employed to group the weights for the same brain region across different time-points together. Furthermore, to reflect the smooth changes between data derived from adjacent time-points, we incorporate two smoothness regularization terms into the objective function, i.e., one fused smoothness term which requires that the differences between two successive weight vectors from adjacent time-points should be small, and another output smoothness term which requires the differences between outputs of two successive models from adjacent time-points should also be small. We develop an efficient optimization algorithm to solve the proposed objective function. Experimental results on ADNI database demonstrate that, compared with conventional sparse learning-based methods, our proposed method can achieve improved regression performance and also help in discovering disease-related biomarkers. PMID:27093313

The debate over diagnosis related groups.

PubMed

Spiegel, A D; Kavaler, F

1985-01-01

With the advent of the Prospective Payment System (PPS) using Diagnosis Related Groups (DRGs) as a classification method, the pros and cons of that mechanism have been sharply debated. Grouping the comments into categories related to administration/management, DRG system and quality of care, a review of relevant literature highlights the pertinent attitudes and views of professionals and organizations. Points constantly argued include data utilization, meaningful medical classifications, resource use, gaming, profit centers, patient homogeneity, severity of illness, length of stay, technology limitations and the erosion of standards.

Inhibitor effects during the cell cycle in Chlamydomonas reinhardtii. Determination of transition points in asynchronous cultures

PubMed Central

1975-01-01

A wide variety of inhibitors (drugs, antibiotics, and antimetabolites) will block cell division within an ongoing cell cycle in autotrophic cultures of Chlamydomonas reinhardtii. To determine when during the cell cycle a given inhibitor is effective in preventing cell division, a technique is described which does not rely on the use of synchronous cultures. The technique permits the measurement of transition points, the cell cycle stage at which the subsequent cell division becomes insensitive to the effects of an inhibitor. A map of transition points in the cell cycle reveals that they are grouped into two broad periods, the second and fourth quarters. In general, inhibitors which block organellar DNA, RNA, and protein synthesis have second-quarter transition points, while those which inhibit nuclear cytoplasmic macromolecular synthesis have fourth-quarter transition points. The specific grouping of these transition points into two periods suggests that the synthesis of organellar components is completed midway through the cell cycle and that the synthesis of nonorganellar components required for cell division is not completed until late in the cell cycle. PMID:1176526

On physical property tensors invariant under line groups.

PubMed

Litvin, Daniel B

2014-03-01

The form of physical property tensors of a quasi-one-dimensional material such as a nanotube or a polymer can be determined from the point group of its symmetry group, one of an infinite number of line groups. Such forms are calculated using a method based on the use of trigonometric summations. With this method, it is shown that materials invariant under infinite subsets of line groups have physical property tensors of the same form. For line group types of a family of line groups characterized by an index n and a physical property tensor of rank m, the form of the tensor for all line group types indexed with n > m is the same, leaving only a finite number of tensor forms to be determined.

Synthesis of boron suboxide from boron and boric acid under mild pressure and temperature conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiao, Xiaopeng; Jin, Hua; Ding, Zhanhui

2011-05-15

Graphical abstract: Well-crystallized and icosahedral B{sub 6}O crystals were prepared by reacting boron and boric acid at milder reaction conditions (1 GPa and 1300 {sup o}C for 2 h) as compared to previous work.. Research highlights: {yields} Well-crystallized icosahedral B{sub 6}O was synthesized by reacting boric acid and boron. {yields} The synthesis conditions (1 GPa and 1300 {sup o}C for 2 h) are milder in comparison with previous work. {yields} The more practical synthesis method may make B{sub 6}O as a potential substitute for diamond in industry. -- Abstract: Boron suboxide (B{sub 6}O) was synthesized by reacting boron and boricmore » acid (H{sub 3}BO{sub 3}) at pressures between 1 and 10 GPa, and at temperatures between 1300 and 1400 {sup o}C. The B{sub 6}O samples prepared were icosahedral with diameters ranging from 20 to 300 nm. Well-crystallized and icosahedral crystals with an average size of {approx}100 nm can be obtained at milder reaction conditions (1 GPa and 1300 {sup o}C for 2 h) as compared to previous work. The bulk B{sub 6}O sample was stable in air at 600 {sup o}C and then slowly oxidized up to 1000 {sup o}C. The relatively mild synthetic conditions developed in this study provide a more practical synthesis of B{sub 6}O, which may potentially be used as a substitute for diamond in industry as a new superhard material.« less

Science Using an Electrostatic Levitation Furnace in the MUCAT Sector at the APS

NASA Technical Reports Server (NTRS)

Goldman, A.; Kelton, K. F.; Rogers, J. R.

2004-01-01

The original motivation for the construction of the BESL prototype was to obtain the first proof of a 50-year-old hypothesis regarding the solidification of liquid metals. Since the 1950s it has been known that under proper conditions liquid metals can be cooled below their melting temperature (undercooled) without crystallizing to the stable solid phase. In 1952 Frank proposed that this was because the atoms in the metallic liquid were arranged with the symmetry of an icosahedron, a Platonic solid consisting of 20 tetrahedra (4-sided pyramid-shaped polyhedra) arranged around a common center. Since this local atomic order is incompatible with the long-range translational periodicity of crystal phases, a barrier is formed to the formation of small regions of the crystal phase, the nucleation barrier. A proof of Frank's hypothesis required a direct correlation between measured icosahedral order in the undercooled liquid and the nucleation barrier. The tendency of sample containers to catalyze nucleation obscured this relation, requiring containerless techniques. Combining containerless processing techniques for electrostatically levitated droplets (ESL) with x-ray synchrotron methods, a team from Washington University, St. Louis, MO, NASA Marshall Space Flight Center, and MUCAT at the APS demonstrated an increasing icosahedral order in TiZrNi liquids with decreasing temperature below the melting temperature. The increased icosahedral order caused the transformation of the liquid to a metastable icosahedral quasicrystal phase, instead of the stable tetrahedrally-coordinated crystal intermetallic, giving the first clear demonstration of the connection between the nucleation barrier and the local structure of the liquid, verifying Frank's hypothesis for this alloy.

Compatible Basal Area and Number of Trees Estimators from Remeasured Horizontal Point Samples

Treesearch

Francis A. Roesch; Edwin J. Green; Charles T. Scott

1989-01-01

Compatible groups of estimators for total value at time 1 (V1), survivor growth (S), and ingrowth (I) for use with permanent horizontal point samples are evaluated for the special cases of estimating the change in both the number of trees and basal area. Caveats which should be observed before any one compatible grouping of estimators is chosen...

Point prevalence of neurosis in the Lundby Study 1947-1997.

PubMed

Nilsson, Erik; Bogren, Mats; Mattisson, Cecilia; Nettelbladt, Per

2007-01-01

The objective of this article is to report and discuss the changing point prevalence rate of neurosis 1947-1997 in the Lundby cohort. The Lundby Study is a prospective longitudinal study of a geographically defined total population in the south of Sweden. Field investigations were performed in 1947, 1957, 1972 and in 1997, with psychiatrists interviewing the probands in a semi-structured way. Additional information was gathered from registers, case notes and key informants. Throughout the period of 50 years, the Lundby Study used its own diagnostic system with neurosis referring to non-psychotic mental illness in the absence of an organic brain disease. After 1957, no newcomers were included, and therefore only probands 40 years of age or older at the cross-sectional surveys are included in the present paper. For men aged 40-59 and 60 years or older, respectively, the age-specific point prevalence of neurosis increased from 2.5% and 0.5% in 1947, to 8.3% and 8.4% in 1972. The corresponding figures for women were 8.0% and 1.3% in 1947, and 24.2% and 20.1% in 1972. The increase could be seen in all degrees of impairment, but it was most pronounced in the mild and medium impairment groups. Except for a slight decrease in point prevalence in the female group 40-59 years of age, there were no significant changes from 1972 to 1997. A large increase in the point prevalence rate of neurosis could be seen 1947-1972, but not 1972-1997. Because of the many biases inherent in longitudinal psychiatric studies, our results must be interpreted with caution.

The Whole-Hand Point: The Structure and Function of Pointing From a Comparative Perspective

PubMed Central

Leavens, David A.; Hopkins, William D.

2007-01-01

Pointing by monkeys, apes, and human infants is reviewed and compared. Pointing with the index finger is a species-typical human gesture, although human infants exhibit more whole-hand pointing than is commonly appreciated. Captive monkeys and feral apes have been reported to only rarely “spontaneously” point, although apes in captivity frequently acquire pointing, both with the index finger and with the whole hand, without explicit training. Captive apes exhibit relatively more gaze alternation while pointing than do human infants about 1 year old. Human infants are relatively more vocal while pointing than are captive apes, consistent with paralinguistic use of pointing. PMID:10608565

Molecular symmetry with quaternions.

PubMed

Fritzer, H P

2001-09-01

A new and relatively simple version of the quaternion calculus is offered which is especially suitable for applications in molecular symmetry and structure. After introducing the real quaternion algebra and its classical matrix representation in the group SO(4) the relations with vectors in 3-space and the connection with the rotation group SO(3) through automorphism properties of the algebra are discussed. The correlation of the unit quaternions with both the Cayley-Klein and the Euler parameters through the group SU(2) is presented. Besides rotations the extension of quaternions to other important symmetry operations, reflections and the spatial inversion, is given. Finally, the power of the quaternion calculus for molecular symmetry problems is revealed by treating some examples applied to icosahedral symmetry.

Structure of large dsDNA viruses

PubMed Central

Klose, Thomas; Rossmann, Michael G.

2015-01-01

Nucleocytoplasmic large dsDNA viruses (NCLDVs) encompass an ever-increasing group of large eukaryotic viruses, infecting a wide variety of organisms. The set of core genes shared by all these viruses includes a major capsid protein with a double jelly-roll fold forming an icosahedral capsid, which surrounds a double layer membrane that contains the viral genome. Furthermore, some of these viruses, such as the members of the Mimiviridae and Phycodnaviridae have a unique vertex that is used during infection to transport DNA into the host. PMID:25003382

The registration of non-cooperative moving targets laser point cloud in different view point

NASA Astrophysics Data System (ADS)

Wang, Shuai; Sun, Huayan; Guo, Huichao

2018-01-01

Non-cooperative moving target multi-view cloud registration is the key technology of 3D reconstruction of laser threedimension imaging. The main problem is that the density changes greatly and noise exists under different acquisition conditions of point cloud. In this paper, firstly, the feature descriptor is used to find the most similar point cloud, and then based on the registration algorithm of region segmentation, the geometric structure of the point is extracted by the geometric similarity between point and point, The point cloud is divided into regions based on spectral clustering, feature descriptors are created for each region, searching to find the most similar regions in the most similar point of view cloud, and then aligning the pair of point clouds by aligning their minimum bounding boxes. Repeat the above steps again until registration of all point clouds is completed. Experiments show that this method is insensitive to the density of point clouds and performs well on the noise of laser three-dimension imaging.

Congruence analysis of point clouds from unstable stereo image sequences

NASA Astrophysics Data System (ADS)

Jepping, C.; Bethmann, F.; Luhmann, T.

2014-06-01

This paper deals with the correction of exterior orientation parameters of stereo image sequences over deformed free-form surfaces without control points. Such imaging situation can occur, for example, during photogrammetric car crash test recordings where onboard high-speed stereo cameras are used to measure 3D surfaces. As a result of such measurements 3D point clouds of deformed surfaces are generated for a complete stereo sequence. The first objective of this research focusses on the development and investigation of methods for the detection of corresponding spatial and temporal tie points within the stereo image sequences (by stereo image matching and 3D point tracking) that are robust enough for a reliable handling of occlusions and other disturbances that may occur. The second objective of this research is the analysis of object deformations in order to detect stable areas (congruence analysis). For this purpose a RANSAC-based method for congruence analysis has been developed. This process is based on the sequential transformation of randomly selected point groups from one epoch to another by using a 3D similarity transformation. The paper gives a detailed description of the congruence analysis. The approach has been tested successfully on synthetic and real image data.

Do pencil-point spinal needles decrease the incidence of postdural puncture headache in reality? A comparative study between pencil-point 25G Whitacre and cutting-beveled 25G Quincke spinal needles in 320 obstetric patients.

PubMed

Pal, Anirban; Acharya, Amita; Pal, Nidhi Dawar; Dawn, Satrajit; Biswas, Jhuma

2011-01-01

Postdural puncture headache (PDPH) is a distressing complication of the subarachnoid block. The previous studies conducted, including the recent ones, do not conclusively prove that pencil-point spinal needles decrease the incidence of PDPH. In this study, we have tried to find out whether a pencil-point Whitacre needle is a better alternative than the classic cutting beveled, commonly used, Quincke spinal needle, in patients at risk of PDPH. Three hundred and twenty obstetric patients, 20-36 years of age, ASA I and II, posted for Cesarean section under subarachnoid block, were randomly assigned into two groups W and Q, where 25G Whitacre and 25G Quincke spinal needles were used, respectively. The primary objective of the study was to find out the difference in incidence of PDPH, if any, between the two groups, by using the t test and Chi square test. The incidence of PDPH was 5% in group W and 28.12% in group Q, and the difference in incidence was statistically significant (P<0.001). The pencil-point 25G Whitacre spinal needle causes less incidence of PDPH compared to the classic 25G Quincke needle, and is recommended for use in patients at risk of PDPH.

Do pencil-point spinal needles decrease the incidence of postdural puncture headache in reality? A comparative study between pencil-point 25G Whitacre and cutting-beveled 25G Quincke spinal needles in 320 obstetric patients

PubMed Central

Pal, Anirban; Acharya, Amita; Pal, Nidhi Dawar; Dawn, Satrajit; Biswas, Jhuma

2011-01-01

Background: Postdural puncture headache (PDPH) is a distressing complication of the subarachnoid block. The previous studies conducted, including the recent ones, do not conclusively prove that pencil-point spinal needles decrease the incidence of PDPH. In this study, we have tried to find out whether a pencil-point Whitacre needle is a better alternative than the classic cutting beveled, commonly used, Quincke spinal needle, in patients at risk of PDPH. Materials and Methods: Three hundred and twenty obstetric patients, 20-36 years of age, ASA I and II, posted for Cesarean section under subarachnoid block, were randomly assigned into two groups W and Q, where 25G Whitacre and 25G Quincke spinal needles were used, respectively. The primary objective of the study was to find out the difference in incidence of PDPH, if any, between the two groups, by using the t test and Chi square test. Results: The incidence of PDPH was 5% in group W and 28.12% in group Q, and the difference in incidence was statistically significant (P<0.001). Conclusion: The pencil-point 25G Whitacre spinal needle causes less incidence of PDPH compared to the classic 25G Quincke needle, and is recommended for use in patients at risk of PDPH. PMID:25885381

[Dancing with Pointe Shoes: Characteristics and Assessment Criteria for Pointe Readiness].

PubMed

Wanke, Eileen M; Exner-Grave, Elisabeth

2017-12-01

Training with pointe shoes is an integral part of professional dance education and ambitious hobby dancing. Pointe shoes - developed more than hundred years ago and almost unaltered since then - are highly specific and strike a balance between aesthetics, function, protection, and health care. Therefore, pointe readiness should be tested prior to all dance training or career training. Medical specialists are often confronted with this issue. Specific anatomical dance technique-orientated general conditional and coordinative preconditions as well as dance-technical prerequisites must be met by pointe readiness tests in order to keep traumatic injuries or long-term damage at a minimum. In addition to a (training) history, medical counselling sessions have come to include various tests that enable a reliable decision for or against pointe work. This article suggests adequate testing procedures (STT TEST), taking account of professional dancing as well as hobby dancing. © Georg Thieme Verlag KG Stuttgart · New York.

[Side Effects of Occupational Group Therapy].

PubMed

Flöge, B; Fay, D; Jöbges, M; Linden, M; Muschalla, B

2016-12-01

Background: Occupational therapy is an important co-therapy in psychiatric therapy. It is a common belief that no risks are associated with occupational therapy. Negative effects caused by group therapy, especially occupational therapy, have not been in the focus of research yet. In this study we want to illustrate possible types and intensities of group side effects through occupational therapy. Patients and Methods: Patients of an inpatient rehabilitation facility filled out the Adverse Treatment Reaction Group Checklist. The checklist contains 47 items divided in six dimensions: group size, content, group participants, group outcome and global. The self-rating used a 5-point likert scale (0 = not at all; 4 = very much, extremely stressful) and gives information about types and intensities of the side effects. Results: 88.9 % of 45 patients reported negative effects of occupational group therapy. 28.9 % of the patients rated the side effect as at least severe. Discussion: Occupational therapy is associated with side effects as every other group therapy. Possible side effects caused by group therapy should be considered while planning and implementing occupational therapy. © Georg Thieme Verlag KG Stuttgart · New York.

Experiment Comparison between Engineering Acid Dew Point and Thermodynamic Acid Dew Point

NASA Astrophysics Data System (ADS)

Song, Jinghui; Yuan, Hui; Deng, Jianhua

2018-06-01

in order to realize the accurate prediction of acid dew point, a set of measurement system of acid dew point for the flue gas flue gas in the tail of the boiler was designed and built, And measured at the outlet of an air preheater of a power plant of 1 000 MW, The results show that: Under the same conditions, with the test temperature decreases, Nu of heat transfer tubes, fouling and corrosion of pipe wall and corrosion pieces gradually deepened. Then, the measured acid dew point is compared with the acid dew point obtained by using the existing empirical formula under the same coal type. The dew point of engineering acid is usually about 40 ° lower than the dew point of thermodynamic acid because of the coupling effect of fouling on the acid liquid, which can better reflect the actual operation of flue gas in engineering and has certain theoretical guidance for the design and operation of deep waste heat utilization system significance.

SOFIA pointing history

NASA Astrophysics Data System (ADS)

Kärcher, Hans J.; Kunz, Nans; Temi, Pasquale; Krabbe, Alfred; Wagner, Jörg; Süß, Martin

2014-07-01

The original pointing accuracy requirement of the Stratospheric Observatory for Infrared Astronomy SOFIA was defined at the beginning of the program in the late 1980s as very challenging 0.2 arcsec rms. The early science flights of the observatory started in December 2010 and the observatory has reached in the mean time nearly 0.7 arcsec rms, which is sufficient for most of the SOFIA science instruments. NASA and DLR, the owners of SOFIA, are planning now a future 4 year program to bring the pointing down to the ultimate 0.2 arcsec rms. This may be the right time to recall the history of the pointing requirement and its verification and the possibility of its achievement via early computer models and wind tunnel tests, later computer aided end-to-end simulations up to the first commissioning flights some years ago. The paper recollects the tools used in the different project phases for the verification of the pointing performance, explains the achievements and may give hints for the planning of the upcoming final pointing improvement phase.

Point counts from clustered populations: Lessons from an experiment with Hawaiian crows

USGS Publications Warehouse

Hayward, G.D.; Kepler, C.B.; Scott, J.M.

1991-01-01

We designed an experiment to identify factors contributing most to error in counts of Hawaiian Crow or Alala (Corvus hawaiiensis) groups that are detected aurally. Seven observers failed to detect calling Alala on 197 of 361 3-min point counts on four transects extending from cages with captive Alala. A detection curve describing the relation between frequency of flock detection and distance typified the distribution expected in transect or point counts. Failure to detect calling Alala was affected most by distance, observer, and Alala calling frequency. The number of individual Alala calling was not important in detection rate. Estimates of the number of Alala calling (flock size) were biased and imprecise: average difference between number of Alala calling and number heard was 3.24 (.+-. 0.277). Distance, observer, number of Alala calling, and Alala calling frequency all contributed to errors in estimates of group size (P < 0.0001). Multiple regression suggested that number of Alala calling contributed most to errors. These results suggest that well-designed point counts may be used to estimate the number of Alala flocks but cast doubt on attempts to estimate flock size when individuals are counted aurally.

Pointo - a Low Cost Solution to Point Cloud Processing

NASA Astrophysics Data System (ADS)

Houshiar, H.; Winkler, S.

2017-11-01

With advance in technology access to data especially 3D point cloud data becomes more and more an everyday task. 3D point clouds are usually captured with very expensive tools such as 3D laser scanners or very time consuming methods such as photogrammetry. Most of the available softwares for 3D point cloud processing are designed for experts and specialists in this field and are usually very large software packages containing variety of methods and tools. This results in softwares that are usually very expensive to acquire and also very difficult to use. Difficulty of use is caused by complicated user interfaces that is required to accommodate a large list of features. The aim of these complex softwares is to provide a powerful tool for a specific group of specialist. However they are not necessary required by the majority of the up coming average users of point clouds. In addition to complexity and high costs of these softwares they generally rely on expensive and modern hardware and only compatible with one specific operating system. Many point cloud customers are not point cloud processing experts or willing to spend the high acquisition costs of these expensive softwares and hardwares. In this paper we introduce a solution for low cost point cloud processing. Our approach is designed to accommodate the needs of the average point cloud user. To reduce the cost and complexity of software our approach focuses on one functionality at a time in contrast with most available softwares and tools that aim to solve as many problems as possible at the same time. Our simple and user oriented design improve the user experience and empower us to optimize our methods for creation of an efficient software. In this paper we introduce Pointo family as a series of connected softwares to provide easy to use tools with simple design for different point cloud processing requirements. PointoVIEWER and PointoCAD are introduced as the first components of the Pointo family to provide a

C-point and V-point singularity lattice formation and index sign conversion methods

NASA Astrophysics Data System (ADS)

Kumar Pal, Sushanta; Ruchi; Senthilkumaran, P.

2017-06-01

The generic singularities in an ellipse field are C-points namely stars, lemons and monstars in a polarization distribution with C-point indices (-1/2), (+1/2) and (+1/2) respectively. Similar to C-point singularities, there are V-point singularities that occur in a vector field and are characterized by Poincare-Hopf index of integer values. In this paper we show that the superposition of three homogenously polarized beams in different linear states leads to the formation of polarization singularity lattice. Three point sources at the focal plane of the lens are used to create three interfering plane waves. A radial/azimuthal polarization converter (S-wave plate) placed near the focal plane modulates the polarization states of the three beams. The interference pattern is found to host C-points and V-points in a hexagonal lattice. The C-points occur at intensity maxima and V-points occur at intensity minima. Modulating the state of polarization (SOP) of three plane waves from radial to azimuthal does not essentially change the nature of polarization singularity lattice as the Poincare-Hopf index for both radial and azimuthal polarization distributions is (+1). Hence a transformation from a star to a lemon is not trivial, as such a transformation requires not a single SOP change, but a change in whole spatial SOP distribution. Further there is no change in the lattice structure and the C- and V-points appear at locations where they were present earlier. Hence to convert an interlacing star and V-point lattice into an interlacing lemon and V-point lattice, the interferometer requires modification. We show for the first time a method to change the polarity of C-point and V-point indices. This means that lemons can be converted into stars and stars can be converted into lemons. Similarly the positive V-point can be converted to negative V-point and vice versa. The intensity distribution in all these lattices is invariant as the SOPs of the three beams are changed in an

Typing of Panton-Valentine leukocidin-encoding phages carried by methicillin-susceptible and methicillin-resistant Staphylococcus aureus from Italy.

PubMed

Sanchini, A; Del Grosso, M; Villa, L; Ammendolia, M G; Superti, F; Monaco, M; Pantosti, A

2014-11-01

Panton-Valentine leukocidin (PVL) is the hallmark of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) but can also be found in methicillin-susceptible S. aureus (MSSA) sharing pathogenic and epidemiological characteristics of CA-MRSA. PVL is encoded by two co-transcribed genes that are carried by different staphylococcal bacteriophages. We applied an extended PCR-based typing scheme for the identification of two morphological groups (elongated-head group and icosahedral-head group I phages) and specific PVL phage types in S. aureus isolates recovered in Italy. We examined 48 PVL-positive isolates (25 MSSA and 23 MRSA) collected from different hospital laboratories from April 2005 to May 2011. spa typing, multilocus sequence typing and staphylococcal cassette chromosome mec typing were applied to categorize the isolates. Phage typeability was 48.0% in MSSA and 91.3% in MRSA, highlighting the limitation of the PCR typing scheme when applied to PVL-positive MSSA. Five different PVL phages and two variants of a known phage were detected, the most prevalent being ΦSa2usa, recovered in 15 out of 48 (31.2%) isolates, and carried by both MSSA and MRSA belonging to CC8 and CC5. The recently described ΦTCH60 was recovered in four isolates. A PVL phage (ΦSa119) from an ST772 MRSA, that was not detected using the previous typing scheme, was sequenced, and new primers were designed for the identification of the icosahedral-head group II PVL phages present in ST772 and ST59 MRSA. A comprehensive PVL-phage typing can contribute to the understanding of the epidemiology and evolution of PVL-positive MSSA and MRSA. © 2014 The Authors Clinical Microbiology and Infection © 2014 European Society of Clinical Microbiology and Infectious Diseases.

Community detection in networks with unequal groups.

PubMed

Zhang, Pan; Moore, Cristopher; Newman, M E J

2016-01-01

Recently, a phase transition has been discovered in the network community detection problem below which no algorithm can tell which nodes belong to which communities with success any better than a random guess. This result has, however, so far been limited to the case where the communities have the same size or the same average degree. Here we consider the case where the sizes or average degrees differ. This asymmetry allows us to assign nodes to communities with better-than-random success by examining their local neighborhoods. Using the cavity method, we show that this removes the detectability transition completely for networks with four groups or fewer, while for more than four groups the transition persists up to a critical amount of asymmetry but not beyond. The critical point in the latter case coincides with the point at which local information percolates, causing a global transition from a less-accurate solution to a more-accurate one.

Critical Point Cancellation in 3D Vector Fields: Robustness and Discussion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skraba, Primoz; Rosen, Paul; Wang, Bei

Vector field topology has been successfully applied to represent the structure of steady vector fields. Critical points, one of the essential components of vector field topology, play an important role in describing the complexity of the extracted structure. Simplifying vector fields via critical point cancellation has practical merit for interpreting the behaviors of complex vector fields such as turbulence. However, there is no effective technique that allows direct cancellation of critical points in 3D. This work fills this gap and introduces the first framework to directly cancel pairs or groups of 3D critical points in a hierarchical manner with amore » guaranteed minimum amount of perturbation based on their robustness, a quantitative measure of their stability. In addition, our framework does not require the extraction of the entire 3D topology, which contains non-trivial separation structures, and thus is computationally effective. Furthermore, our algorithm can remove critical points in any subregion of the domain whose degree is zero and handle complex boundary configurations, making it capable of addressing challenging scenarios that may not be resolved otherwise. Here, we apply our method to synthetic and simulation datasets to demonstrate its effectiveness.« less

Critical Point Cancellation in 3D Vector Fields: Robustness and Discussion.

PubMed

Skraba, Primoz; Rosen, Paul; Wang, Bei; Chen, Guoning; Bhatia, Harsh; Pascucci, Valerio

2016-02-29

Vector field topology has been successfully applied to represent the structure of steady vector fields. Critical points, one of the essential components of vector field topology, play an important role in describing the complexity of the extracted structure. Simplifying vector fields via critical point cancellation has practical merit for interpreting the behaviors of complex vector fields such as turbulence. However, there is no effective technique that allows direct cancellation of critical points in 3D. This work fills this gap and introduces the first framework to directly cancel pairs or groups of 3D critical points in a hierarchical manner with a guaranteed minimum amount of perturbation based on their robustness, a quantitative measure of their stability. In addition, our framework does not require the extraction of the entire 3D topology, which contains non-trivial separation structures, and thus is computationally effective. Furthermore, our algorithm can remove critical points in any subregion of the domain whose degree is zero and handle complex boundary configurations, making it capable of addressing challenging scenarios that may not be resolved otherwise. We apply our method to synthetic and simulation datasets to demonstrate its effectiveness.

Parietal and superior frontal visuospatial maps activated by pointing and saccades

PubMed Central

Hagler, D.J.; Riecke, L.; Sereno, M.I.

2009-01-01

A recent study from our laboratory demonstrated that parietal cortex contains a map of visual space related to saccades and spatial attention and identified this area as the likely human homologue of the lateral intraparietal (LIP). A human homologue for the parietal reach region (PRR), thought to preferentially encode planned hand movements, has also been recently proposed. Both of these areas, originally identified in the macaque monkey, have been shown to encode space with eye-centered coordinates. Functional magnetic resonance imaging (fMRI) of humans was used to test the hypothesis that the putative human PRR contains a retinotopic map recruited by finger pointing but not saccades and to test more generally for differences in the visuospatial maps recruited by pointing and saccades. We identified multiple maps in both posterior parietal cortex and superior frontal cortex recruited for eye and hand movements, including maps not observed in previous mapping studies. Pointing and saccade maps were generally consistent within single subjects. We have developed new group analysis methods for phase-encoded data, which revealed subtle differences between pointing and saccades, including hemispheric asymmetries, but we did not find evidence of pointing-specific maps of visual space. PMID:17376706

Critical Point Cancellation in 3D Vector Fields: Robustness and Discussion

DOE PAGES

Skraba, Primoz; Rosen, Paul; Wang, Bei; ...

2016-02-29

Vector field topology has been successfully applied to represent the structure of steady vector fields. Critical points, one of the essential components of vector field topology, play an important role in describing the complexity of the extracted structure. Simplifying vector fields via critical point cancellation has practical merit for interpreting the behaviors of complex vector fields such as turbulence. However, there is no effective technique that allows direct cancellation of critical points in 3D. This work fills this gap and introduces the first framework to directly cancel pairs or groups of 3D critical points in a hierarchical manner with amore » guaranteed minimum amount of perturbation based on their robustness, a quantitative measure of their stability. In addition, our framework does not require the extraction of the entire 3D topology, which contains non-trivial separation structures, and thus is computationally effective. Furthermore, our algorithm can remove critical points in any subregion of the domain whose degree is zero and handle complex boundary configurations, making it capable of addressing challenging scenarios that may not be resolved otherwise. Here, we apply our method to synthetic and simulation datasets to demonstrate its effectiveness.« less

An Emprical Point Error Model for Tls Derived Point Clouds

NASA Astrophysics Data System (ADS)

Ozendi, Mustafa; Akca, Devrim; Topan, Hüseyin

2016-06-01

The random error pattern of point clouds has significant effect on the quality of final 3D model. The magnitude and distribution of random errors should be modelled numerically. This work aims at developing such an anisotropic point error model, specifically for the terrestrial laser scanner (TLS) acquired 3D point clouds. A priori precisions of basic TLS observations, which are the range, horizontal angle and vertical angle, are determined by predefined and practical measurement configurations, performed at real-world test environments. A priori precision of horizontal (𝜎𝜃) and vertical (𝜎𝛼) angles are constant for each point of a data set, and can directly be determined through the repetitive scanning of the same environment. In our practical tests, precisions of the horizontal and vertical angles were found as 𝜎𝜃=±36.6𝑐𝑐 and 𝜎𝛼=±17.8𝑐𝑐, respectively. On the other hand, a priori precision of the range observation (𝜎𝜌) is assumed to be a function of range, incidence angle of the incoming laser ray, and reflectivity of object surface. Hence, it is a variable, and computed for each point individually by employing an empirically developed formula varying as 𝜎𝜌=±2-12 𝑚𝑚 for a FARO Focus X330 laser scanner. This procedure was followed by the computation of error ellipsoids of each point using the law of variance-covariance propagation. The direction and size of the error ellipsoids were computed by the principal components transformation. The usability and feasibility of the model was investigated in real world scenarios. These investigations validated the suitability and practicality of the proposed method.

When can I start pointe work? Guidelines for initiating pointe training.

PubMed

Weiss, David S; Rist, Rachel Anne; Grossman, Gayanne

2009-01-01

The initiation of pointe training for dance students should be determined after careful evaluation of a number of factors. These include: the dance student's stage of physical development; the quality of her (or his) trunk, abdominal and pelvic control ("core" stability); the alignment of her legs (hip-knee-ankle-foot); the strength and flexibility of her feet and ankles; and the duration and frequency of her dance training. For students who meet the requirements related to all of these factors, began ballet training at age eight or later, and who are taking ballet class at least twice per week, pointe work should be initiated in the fourth year of training. Students with poor core stability or hypermobility of the feet and ankles may require additional strengthening to allow them to safely begin pointe training. For those who are only taking ballet classes once per week, or who are not truly pre-professional, pointe training should be discouraged. No student with insufficient ankle and foot plantar flexion range of motion or with poor lower extremity alignment should be allowed to do pointe work.

Acupuncture point injection treatment of primary dysmenorrhoea: a randomised, double blind, controlled study.

PubMed

Wade, C; Wang, L; Zhao, W J; Cardini, F; Kronenberg, F; Gui, S Q; Ying, Z; Zhao, N Q; Chao, M T; Yu, J

2016-01-05

To determine if injection of vitamin K3 in an acupuncture point is optimal for the treatment of primary dysmenorrhoea, when compared with 2 other injection treatments. A Menstrual Disorder Centre at a public hospital in Shanghai, China. Chinese women aged 14-25 years with severe primary dysmenorrhoea for at least 6 months not relieved by any other treatment were recruited. Exclusion criteria were the use of oral contraceptives, intrauterine devices or anticoagulant drugs, pregnancy, history of abdominal surgery, participation in other therapies for pain and diagnosis of secondary dysmenorrhoea. Eighty patients with primary dysmenorrhoea, as defined on a 4-grade scale, completed the study. Two patients withdrew after randomisation. A double-blind, double-dummy, randomised controlled trial compared vitamin K3 acupuncture point injection to saline acupuncture point injection and vitamin K3 deep muscle injection. Patients in each group received 3 injections at a single treatment visit. The primary outcome was the difference in subjective perception of pain as measured by an 11 unit Numeric Rating Scale (NRS). Secondary measurements were Cox Pain Intensity and Duration scales and the consumption of analgesic tablets before and after treatment and during 6 following cycles. Patients in all 3 groups experienced pain relief from the injection treatments. Differences in NRS measured mean pain scores between the 2 active control groups were less than 1 unit (-0.71, CI -1.37 to -0.05) and not significant, but the differences in average scores between the treatment hypothesised to be optimal and both active control groups (1.11, CI 0.45 to 1.78) and (1.82, CI 1.45 to 2.49) were statistically significant in adjusted mixed-effects models. Menstrual distress and use of analgesics were diminished for 6 months post-treatment. Acupuncture point injection of vitamin K3 relieves menstrual pain rapidly and is a useful treatment in an urban outpatient clinic. NCT00104546; Results

Soap films and GeoGebra in the study of Fermat and Steiner points

NASA Astrophysics Data System (ADS)

Flores, Alfinio; Park, Jungeun

2018-05-01

We discuss how mathematics and secondary mathematics education majors developed an understanding of Fermat points for the triangle as well as Steiner points for the square and regular pentagon, and also of soap film configurations between parallel plates where forces are in equilibrium. The activities included the use of soap films and the interactive geometry program GeoGebra. Students worked in small groups using these tools to investigate the properties of Fermat and Steiner points and then justified the results of their investigations using geometrical arguments. These activities are specific approaches of how to encourage prospective teachers to use physical experiments to support students' development of mathematical curiosity and mathematical justifications.

Point Barrow, Alaska

NASA Image and Video Library

2015-09-10

Point Barrow or Nuvuk, Alaska is the northernmost point of all territory of the United States. It also marks the limit between the Chukchi Sea to the west, and the Beaufort Sea to the east. Archaeological evidence indicates that Point Barrow was occupied about 500 CE, probably as hunting camps for whales. The image covers an area of 32 by 38 km, was acquired July 29, 2015, and is located at 71.6 degrees north, 156.45 degrees west. http://photojournal.jpl.nasa.gov/catalog/PIA19775

Laser Dew-Point Hygrometer

NASA Astrophysics Data System (ADS)

Matsumoto, Shigeaki; Toyooka, Satoru

1995-01-01

A rough-surface-type automatic dew-point hygrometer was developed using a laser diode and an optical fiber cable. A gold plate with 0.8 µ m average surface roughness was used as a surface for deposition of dew to facilitate dew deposition and prevent supersaturation of water vapor at the dew point. It was shown experimentally that the quantity of dew deposited can be controlled to be constant at any predetermined level, and is independent of the dew point to be measured. The dew points were measured in the range from -15° C to 54° C in which the temperature ranged from 0° C to 60° C. The measurement error of the dew point was ±0.5° C which was equal to below ±2% in relative humidity in the above dew-point range.

Telescope pointing for GOPEX

NASA Technical Reports Server (NTRS)

Owen, W. M., Jr.

1993-01-01

In order for photons emitted by the GOPEX lasers to be detected by Galileo's camera, the telescopes at Table Mountain Observatory and Starfire Optical Range had to be pointed in the right direction within a tolerance less than the beam divergence. At both sites nearby stars were used as pointing references. The technical challenge was to ensure that the transmission direction and the star positions were specified in exactly the same coordinate system; given this assurance, neither the uncertainty in the star catalog positions nor the difficulty in offset pointing was expected to exceed the pointing error budget. The correctness of the pointing scheme was verified by the success of GOPEX.

47 CFR 101.137 - Interconnection of private operational fixed point-to-point microwave stations.

Code of Federal Regulations, 2013 CFR

2013-10-01

... point-to-point microwave stations. 101.137 Section 101.137 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Technical Standards § 101.137 Interconnection of private operational fixed point-to-point microwave stations. Private...

47 CFR 101.137 - Interconnection of private operational fixed point-to-point microwave stations.

Code of Federal Regulations, 2011 CFR

2011-10-01

... point-to-point microwave stations. 101.137 Section 101.137 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Technical Standards § 101.137 Interconnection of private operational fixed point-to-point microwave stations. Private...

47 CFR 101.137 - Interconnection of private operational fixed point-to-point microwave stations.

Code of Federal Regulations, 2012 CFR

2012-10-01

... point-to-point microwave stations. 101.137 Section 101.137 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Technical Standards § 101.137 Interconnection of private operational fixed point-to-point microwave stations. Private...

47 CFR 101.137 - Interconnection of private operational fixed point-to-point microwave stations.

Code of Federal Regulations, 2014 CFR

2014-10-01

... point-to-point microwave stations. 101.137 Section 101.137 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Technical Standards § 101.137 Interconnection of private operational fixed point-to-point microwave stations. Private...

47 CFR 101.137 - Interconnection of private operational fixed point-to-point microwave stations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... point-to-point microwave stations. 101.137 Section 101.137 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Technical Standards § 101.137 Interconnection of private operational fixed point-to-point microwave stations. Private...

Archaeal Viruses Multiply: Temporal Screening in a Solar Saltern

PubMed Central

Atanasova, Nina S.; Demina, Tatiana A.; Buivydas, Andrius; Bamford, Dennis H.; Oksanen, Hanna M.

2015-01-01

Hypersaline environments around the world are dominated by archaea and their viruses. To date, very little is known about these viruses and their interaction with the host strains when compared to bacterial and eukaryotic viruses. We performed the first culture-dependent temporal screening of haloarchaeal viruses and their hosts in the saltern of Samut Sakhon, Thailand, during two subsequent years (2009, 2010). Altogether we obtained 36 haloarchaeal virus isolates and 36 archaeal strains, significantly increasing the number of known archaeal virus isolates. Interestingly, the morphological distribution of our temporal isolates (head-tailed, pleomorphic, and icosahedral membrane-containing viruses) was similar to the outcome of our previous spatial survey supporting the observations of a global resemblance of halophilic microorganisms and their viruses. Myoviruses represented the most abundant virus morphotype with strikingly broad host ranges. The other viral morphotypes (siphoviruses, as well as pleomorphic and icosahedral internal membrane-containing viruses) were more host-specific. We also identified a group of Halorubrum strains highly susceptible to numerous different viruses (up to 26). This high virus sensitivity, the abundance of broad host range viruses, and the maintenance of infectivity over a period of one year suggest constant interplay of halophilic microorganisms and their viruses within an extreme environment. PMID:25866903

Archaeal viruses multiply: temporal screening in a solar saltern.

PubMed

Atanasova, Nina S; Demina, Tatiana A; Buivydas, Andrius; Bamford, Dennis H; Oksanen, Hanna M

2015-04-10

Hypersaline environments around the world are dominated by archaea and their viruses. To date, very little is known about these viruses and their interaction with the host strains when compared to bacterial and eukaryotic viruses. We performed the first culture-dependent temporal screening of haloarchaeal viruses and their hosts in the saltern of Samut Sakhon, Thailand, during two subsequent years (2009, 2010). Altogether we obtained 36 haloarchaeal virus isolates and 36 archaeal strains, significantly increasing the number of known archaeal virus isolates. Interestingly, the morphological distribution of our temporal isolates (head-tailed, pleomorphic, and icosahedral membrane-containing viruses) was similar to the outcome of our previous spatial survey supporting the observations of a global resemblance of halophilic microorganisms and their viruses. Myoviruses represented the most abundant virus morphotype with strikingly broad host ranges. The other viral morphotypes (siphoviruses, as well as pleomorphic and icosahedral internal membrane-containing viruses) were more host-specific. We also identified a group of Halorubrum strains highly susceptible to numerous different viruses (up to 26). This high virus sensitivity, the abundance of broad host range viruses, and the maintenance of infectivity over a period of one year suggest constant interplay of halophilic microorganisms and their viruses within an extreme environment.

A Secure Multicast Framework in Large and High-Mobility Network Groups

NASA Astrophysics Data System (ADS)

Lee, Jung-San; Chang, Chin-Chen

With the widespread use of Internet applications such as Teleconference, Pay-TV, Collaborate tasks, and Message services, how to construct and distribute the group session key to all group members securely is becoming and more important. Instead of adopting the point-to-point packet delivery, these emerging applications are based upon the mechanism of multicast communication, which allows the group member to communicate with multi-party efficiently. There are two main issues in the mechanism of multicast communication: Key Distribution and Scalability. The first issue is how to distribute the group session key to all group members securely. The second one is how to maintain the high performance in large network groups. Group members in conventional multicast systems have to keep numerous secret keys in databases, which makes it very inconvenient for them. Furthermore, in case that a member joins or leaves the communication group, many involved participants have to change their own secret keys to preserve the forward secrecy and the backward secrecy. We consequently propose a novel version for providing secure multicast communication in large network groups. Our proposed framework not only preserves the forward secrecy and the backward secrecy but also possesses better performance than existing alternatives. Specifically, simulation results demonstrate that our scheme is suitable for high-mobility environments.

Extracorporeal shock wave therapy of gastroc-soleus trigger points in patients with plantar fasciitis: A randomized, placebo-controlled trial.

PubMed

Moghtaderi, Alireza; Khosrawi, Saeid; Dehghan, Farnaz

2014-01-01

Plantar fasciitis is the most common cause of heel pain. Extracorporeal shock wave therapy (ESWT) is an alternative treatment for refractory cases of plantar fasciitis. Studies also demonstrated that ESWT may be an appropriate treatment for myofascial trigger points. This study was designed to evaluate its effectiveness by comparing the ESWT of Gastrocnemius/Soleus (gastroc-soleus) trigger points and heel region with the ESWT of the heel region alone. The study was carried out among 40 patients with a clinical diagnosis of plantar fasciitis, divided randomly to case (n = 20) and control (n = 20) groups. The case group received ESWT for the heel region and for the gastroc-soleus trigger points. The control group received ESWT just for the heel region. The protocol was the same in both groups and they were treated for three sessions every week. The pain score (100 mm visual analog score [VAS]) and the modified Roles and Maudsley score was evaluated before the first session and eight weeks after the last session. Eight weeks after the last session, although the mean VAS had decreased significantly in both groups, this decrement was more significant in the case group. (P = 0.04). According to the modified Roles and Maudsley score, there was a significant improvement in both the case (P < 0.001) and control (P = 0.01) groups, eight weeks after treatment, but there were significantly better results in the case group. The combination of ESWT for both plantar fasciitis and gastroc-soleus trigger points in treating patients with plantar fasciitis is more effective than utilizing it solely for plantar fasciitis.

Marine Point Forecasts

Science.gov Websites

with smartphones and other mobile platforms new Marine Point Forecasts are a forecast for a specific maps providing zone/point marine forecasts Mobile, AL Eureka, CA San Francisco, CA Los Angeles, CA San

Group-theoretical analysis of two-dimensional hexagonal materials

NASA Astrophysics Data System (ADS)

Minami, Susumu; Sugita, Itaru; Tomita, Ryosuke; Oshima, Hiroyuki; Saito, Mineo

2017-10-01

Two-dimensional hexagonal materials such as graphene and silicene have highly symmetric crystal structures and Dirac cones at the K point, which induce novel electronic properties. In this report, we calculate their electronic structures by using density functional theory and analyze their band structures on the basis of the group theory. Dirac cones frequently appear when the symmetry at the K point is high; thus, two-dimensional irreducible representations are included. We discuss the relationship between symmetry and the appearance of the Dirac cone.

Utilizing PowerPoint Presentation to Promote Fall Prevention among Older Adults

ERIC Educational Resources Information Center

McCrary-Quarles, Audrey R.

2008-01-01

This study evaluated a PowerPoint home safety (PPHS) presentation in enhancing awareness, knowledge and behavior change among senior center attendees in southern Illinois. Twelve centers were utilized as data collection sites in a pretest-posttest control group design. Through stratified randomization, centers were placed into categories (high,…

Electroacupuncture effect at the LI 4 Hegu point on the plasma β-endorphin level of healthy subjects

NASA Astrophysics Data System (ADS)

Setiawardhani, A. L.; Srilestari, A.; Simadibrata, C.

2017-08-01

As a therapy modality, acupuncture is becoming popular for treating diseases. Nevertheless, the acupuncture mechanism of action remains unclear until now. Some studies suggest that acupuncture works by stimulating the β-endorphin release, whereas other studies show the opposite. This study aims to determine whether electro acupuncture at the LI 4 Hegu point could increase the plasma β-endorphin level as a basic of acupuncture mechanism of action. Thirty-six healthy subjects were involved and divided randomly into two groups, namely, intervention (n=18) and control (n=18). In the intervention group, electroacupuncture was applied at the LI 4 Hegu point with a low frequency for 30 min. In the control group, sham electroacupuncture was applied at a non-acupoint for 30 min. The plasma β-endorphin was examined before and after intervention using the ELISA method. A significant difference was found between the intervention and control groups in increasing the plasma β-endorphin level (9(50%) vs. 1(5.6%); p = 0.009). A significant difference was also observed in the plasma β-endorphin level after intervention between the two groups (35.1±3.4 vs. 10.3±1.8 p=0.003). Electroacupuncture at the LI 4 Hegu point was found to increase the plasma β-endorphin level in healthy subjects.

Acupuncture point injection treatment of primary dysmenorrhoea: a randomised, double blind, controlled study

PubMed Central

Wade, C; Wang, L; Zhao, W J; Cardini, F; Kronenberg, F; Gui, S Q; Ying, Z; Zhao, N Q; Chao, M T; Yu, J

2016-01-01

Objective To determine if injection of vitamin K3 in an acupuncture point is optimal for the treatment of primary dysmenorrhoea, when compared with 2 other injection treatments. Setting A Menstrual Disorder Centre at a public hospital in Shanghai, China. Participants Chinese women aged 14–25 years with severe primary dysmenorrhoea for at least 6 months not relieved by any other treatment were recruited. Exclusion criteria were the use of oral contraceptives, intrauterine devices or anticoagulant drugs, pregnancy, history of abdominal surgery, participation in other therapies for pain and diagnosis of secondary dysmenorrhoea. Eighty patients with primary dysmenorrhoea, as defined on a 4-grade scale, completed the study. Two patients withdrew after randomisation. Interventions A double-blind, double-dummy, randomised controlled trial compared vitamin K3 acupuncture point injection to saline acupuncture point injection and vitamin K3 deep muscle injection. Patients in each group received 3 injections at a single treatment visit. Primary and secondary outcome measures The primary outcome was the difference in subjective perception of pain as measured by an 11 unit Numeric Rating Scale (NRS). Secondary measurements were Cox Pain Intensity and Duration scales and the consumption of analgesic tablets before and after treatment and during 6 following cycles. Results Patients in all 3 groups experienced pain relief from the injection treatments. Differences in NRS measured mean pain scores between the 2 active control groups were less than 1 unit (−0.71, CI −1.37 to −0.05) and not significant, but the differences in average scores between the treatment hypothesised to be optimal and both active control groups (1.11, CI 0.45 to 1.78) and (1.82, CI 1.45 to 2.49) were statistically significant in adjusted mixed-effects models. Menstrual distress and use of analgesics were diminished for 6 months post-treatment. Conclusions Acupuncture point injection of

Using appropriate body mass index cut points for overweight and obesity among Asian Americans

PubMed Central

Jih, Jane; Mukherjea, Arnab; Vittinghoff, Eric; Nguyen, Tung T.; Tsoh, Janice Y.; Fukuoka, Yoshimi; Bender, Melinda S.; Tseng, Winston; Kanaya, Alka M.

2014-01-01

Objective Asian Americans have low prevalence of overweight/obesity based on standard BMI cut points yet have higher rates of diabetes. We examined the prevalence of overweight/obesity, using lower BMI cut points recommended by the World Health Organization (WHO) for Asians, and diabetes in Asian American subgroups in California. Method Secondary analysis of the 2009 adult California Health Interview Survey (n = 45,946) of non-Hispanic Whites (NHW), African Americans, Hispanics and Asians (Vietnamese, Chinese, Korean, Filipino, South Asian and Japanese). WHO Asian BMI cut points (overweight = 23–27.5 kg/m2; obese ≥ 27.5 kg/m2) were used for Asian subgroups. Standard BMI cut points (overweight = 25–29.9 kg/m2; obese ≥ 30 kg/m2) were applied for other groups. Results Among Asian subgroups, overweight/obesity was highest among Filipinos (78.6%), which was higher than NHWs (p < 0.001) but similar to African Americans and Hispanics. Compared to NHW, diabetes prevalence was higher for Vietnamese, Koreans, Filipinos and South Asians with BMI = 23–24.9 kg/m2 and Koreans, Filipinos and Japanese with BMI = 27.5–29.9 kg/m2, the ranges WHO recommends as overweight or obese for Asians but not for other groups. Conclusions Filipinos should be a priority population for overweight/obesity screening. Filipinos, Vietnamese, Korean, South Asians and Japanese have higher diabetes prevalence at lower BMI cut points. WHO Asian BMI cut points may have clinical utility to identify at-risk Asian Americans. PMID:24736092

Using appropriate body mass index cut points for overweight and obesity among Asian Americans.

PubMed

Jih, Jane; Mukherjea, Arnab; Vittinghoff, Eric; Nguyen, Tung T; Tsoh, Janice Y; Fukuoka, Yoshimi; Bender, Melinda S; Tseng, Winston; Kanaya, Alka M

2014-08-01

Asian Americans have low prevalence of overweight/obesity based on standard BMI cut points yet have higher rates of diabetes. We examined the prevalence of overweight/obesity, using lower BMI cut points recommended by the World Health Organization (WHO) for Asians, and diabetes in Asian American subgroups in California. Secondary analysis of the 2009 adult California Health Interview Survey (n=45,946) of non-Hispanic Whites (NHW), African Americans, Hispanics and Asians (Vietnamese, Chinese, Korean, Filipino, South Asian and Japanese). WHO Asian BMI cut points (overweight=23-27.5kg/m(2); obese≥27.5kg/m(2)) were used for Asian subgroups. Standard BMI cut points (overweight=25-29.9kg/m(2); obese≥30kg/m(2)) were applied for other groups. Among Asian subgroups, overweight/obesity was highest among Filipinos (78.6%), which was higher than NHWs (p<0.001) but similar to African Americans and Hispanics. Compared to NHW, diabetes prevalence was higher for Vietnamese, Koreans, Filipinos and South Asians with BMI=23-24.9kg/m(2) and Koreans, Filipinos and Japanese with BMI=27.5-29.9kg/m(2), the ranges WHO recommends as overweight or obese for Asians but not for other groups. Filipinos should be a priority population for overweight/obesity screening. Filipinos, Vietnamese, Korean, South Asians and Japanese have higher diabetes prevalence at lower BMI cut points. WHO Asian BMI cut points may have clinical utility to identify at-risk Asian Americans. Copyright © 2014 Elsevier Inc. All rights reserved.

[Efficacy on nervous tinnitus of kidney deficiency treated with Zhuang medicine at Qineihuan point and conventional acupuncture therapy].

PubMed

Li, Xiujuan; Li, Jie; Han, Haitao; Huang, Jinming; Li, Meikang; Lu Xuanlin; Song, Ning; Lin, Hua-sheng; Li, Xuemei; Huang, Guihua

2015-04-01

To compare the difference of the clinical efficacy in treatment of nervous tinnitus of kidney deficiency between the combined therapy of Zhuang medicine at Qineihuan point combined with the conventional acupuncture and simple conventional acupancture. Sixty patients were randomized into an observation group and a control group, 30 cases in each one. In the control group, the conventional acupuncture was applied to Taixi (KI 3), Zhaohai (KI 6), Tinggong (SI 19) and Waiguan (TE 5), etc. and the needles were retained for 30 min. In the observation group, on the basic treatment as the control group, Zhuang medicine acupuncture at Qineihuan point was added. The treatment was given once every day, 10 treatments made one session and there were 2 days of interval between the sessions. In 3 sessions of treatment, the changes of tinnitus were observed and the clinical efficacy was evaluated. After treatment, tinnitus score and tinnitus grade were all improved as compared with those before treatment in the two groups (all P<0. 05) and the results in the observation group were better than those in the control group (all P<0. 05). The curative and remarkably effective rate was 63. 3% (19/30) and the total effective rate was 93. 3% (28/30) in the observation group, better than 30. 0% (9/30) and 73. 3% (22/30) in the control group (both P<0. 05). The combined therapy of Zhuang medicine at Qineihuan point and conventional acupuncture achieves the better efficacy on nervous tinnitus of kidney deficiency as compared with the simple conventional acupuncture.

Viral Uncoating Is Directional: Exit of the Genomic RNA in a Common Cold Virus Starts with the Poly-(A) Tail at the 3′-End

PubMed Central

Sedivy, Arthur; Subirats, Xavier; Kowalski, Heinrich; Köhler, Gottfried; Blaas, Dieter

2013-01-01

Upon infection, many RNA viruses reorganize their capsid for release of the genome into the host cell cytosol for replication. Often, this process is triggered by receptor binding and/or by the acidic environment in endosomes. In the genus Enterovirus, which includes more than 150 human rhinovirus (HRV) serotypes causing the common cold, there is persuasive evidence that the viral RNA exits single-stranded through channels formed in the protein shell. We have determined the time-dependent emergence of the RNA ends from HRV2 on incubation of virions at 56°C using hybridization with specific oligonucleotides and detection by fluorescence correlation spectroscopy. We report that psoralen UV crosslinking prevents complete RNA release, allowing for identification of the sequences remaining inside the capsid. We also present the structure of uncoating intermediates in which parts of the RNA are condensed and take the form of a rod that is directed roughly towards a two-fold icosahedral axis, the presumed RNA exit point. Taken together, in contrast to schemes frequently depicted in textbooks and reviews, our findings demonstrate that exit of the RNA starts from the 3′-end. This suggests that packaging also occurs in an ordered manner resulting in the 3′-poly-(A) tail becoming located close to a position of pore formation during conversion of the virion into a subviral particle. This directional genome release may be common to many icosahedral non-enveloped single-stranded RNA viruses. PMID:23592991

Two-Point Orientation Discrimination Versus the Traditional Two-Point Test for Tactile Spatial Acuity Assessment

PubMed Central

Tong, Jonathan; Mao, Oliver; Goldreich, Daniel

2013-01-01

Two-point discrimination is widely used to measure tactile spatial acuity. The validity of the two-point threshold as a spatial acuity measure rests on the assumption that two points can be distinguished from one only when the two points are sufficiently separated to evoke spatially distinguishable foci of neural activity. However, some previous research has challenged this view, suggesting instead that two-point task performance benefits from an unintended non-spatial cue, allowing spuriously good performance at small tip separations. We compared the traditional two-point task to an equally convenient alternative task in which participants attempt to discern the orientation (vertical or horizontal) of two points of contact. We used precision digital readout calipers to administer two-interval forced-choice versions of both tasks to 24 neurologically healthy adults, on the fingertip, finger base, palm, and forearm. We used Bayesian adaptive testing to estimate the participants’ psychometric functions on the two tasks. Traditional two-point performance remained significantly above chance levels even at zero point separation. In contrast, two-point orientation discrimination approached chance as point separation approached zero, as expected for a valid measure of tactile spatial acuity. Traditional two-point performance was so inflated at small point separations that 75%-correct thresholds could be determined on all tested sites for fewer than half of participants. The 95%-correct thresholds on the two tasks were similar, and correlated with receptive field spacing. In keeping with previous critiques, we conclude that the traditional two-point task provides an unintended non-spatial cue, resulting in spuriously good performance at small spatial separations. Unlike two-point discrimination, two-point orientation discrimination rigorously measures tactile spatial acuity. We recommend the use of two-point orientation discrimination for neurological assessment. PMID

Hierarchical Regularization of Polygons for Photogrammetric Point Clouds of Oblique Images

NASA Astrophysics Data System (ADS)

Xie, L.; Hu, H.; Zhu, Q.; Wu, B.; Zhang, Y.

2017-05-01

Despite the success of multi-view stereo (MVS) reconstruction from massive oblique images in city scale, only point clouds and triangulated meshes are available from existing MVS pipelines, which are topologically defect laden, free of semantical information and hard to edit and manipulate interactively in further applications. On the other hand, 2D polygons and polygonal models are still the industrial standard. However, extraction of the 2D polygons from MVS point clouds is still a non-trivial task, given the fact that the boundaries of the detected planes are zigzagged and regularities, such as parallel and orthogonal, cannot preserve. Aiming to solve these issues, this paper proposes a hierarchical polygon regularization method for the photogrammetric point clouds from existing MVS pipelines, which comprises of local and global levels. After boundary points extraction, e.g. using alpha shapes, the local level is used to consolidate the original points, by refining the orientation and position of the points using linear priors. The points are then grouped into local segments by forward searching. In the global level, regularities are enforced through a labeling process, which encourage the segments share the same label and the same label represents segments are parallel or orthogonal. This is formulated as Markov Random Field and solved efficiently. Preliminary results are made with point clouds from aerial oblique images and compared with two classical regularization methods, which have revealed that the proposed method are more powerful in abstracting a single building and is promising for further 3D polygonal model reconstruction and GIS applications.

Alien calculus and a Schwinger-Dyson equation: two-point function with a nonperturbative mass scale

NASA Astrophysics Data System (ADS)

Bellon, Marc P.; Clavier, Pierre J.

2018-02-01

Starting from the Schwinger-Dyson equation and the renormalization group equation for the massless Wess-Zumino model, we compute the dominant nonperturbative contributions to the anomalous dimension of the theory, which are related by alien calculus to singularities of the Borel transform on integer points. The sum of these dominant contributions has an analytic expression. When applied to the two-point function, this analysis gives a tame evolution in the deep euclidean domain at this approximation level, making doubtful the arguments on the triviality of the quantum field theory with positive β -function. On the other side, we have a singularity of the propagator for timelike momenta of the order of the renormalization group invariant scale of the theory, which has a nonperturbative relationship with the renormalization point of the theory. All these results do not seem to have an interpretation in terms of semiclassical analysis of a Feynman path integral.

Investigation of the Hosgri Fault, offshore Southern California, Point Sal to Point Conception

USGS Publications Warehouse

Payne, C.M.; Swanson, O.E.; Schell, B.A.

1979-01-01

A high-resolution seismic reflection survey of the inner continental shelf between Point Sal and Point Conception has revealed faults that displace post-Wisconsin strata (less than 17,000-20,000 years). These faults are the Hosgri fault, the Offshore Lompoc fault, and smaller unnamed faults. Faults trending offshore from the adjacent shoreline such as the Pezzoni, Lions Head, Honda, and Pacifico faults, do not show post-Wisconsin activity. The Hosgri fault trends directly toward the coastline between Purisima Point and Point Arguello where it appears to merge with folds and smaller faults in the western Transverse Ranges. This trend of offshore structures toward the Point Arguello-Point Conception area is consistent with a hypothesis that the regional structural fabric of the southern California Coast Ranges and its adjacent offshore area merge with the Transverse Ranges.

Effects of aging on identifying emotions conveyed by point-light walkers.

PubMed

Spencer, Justine M Y; Sekuler, Allison B; Bennett, Patrick J; Giese, Martin A; Pilz, Karin S

2016-02-01

The visual system is able to recognize human motion simply from point lights attached to the major joints of an actor. Moreover, it has been shown that younger adults are able to recognize emotions from such dynamic point-light displays. Previous research has suggested that the ability to perceive emotional stimuli changes with age. For example, it has been shown that older adults are impaired in recognizing emotional expressions from static faces. In addition, it has been shown that older adults have difficulties perceiving visual motion, which might be helpful to recognize emotions from point-light displays. In the current study, 4 experiments were completed in which older and younger adults were asked to identify 3 emotions (happy, sad, and angry) displayed by 4 types of point-light walkers: upright and inverted normal walkers, which contained both local motion and global form information; upright scrambled walkers, which contained only local motion information; and upright random-position walkers, which contained only global form information. Overall, emotion discrimination accuracy was lower in older participants compared with younger participants, specifically when identifying sad and angry point-light walkers. In addition, observers in both age groups were able to recognize emotions from all types of point-light walkers, suggesting that both older and younger adults are able to recognize emotions from point-light walkers on the basis of local motion or global form. (c) 2016 APA, all rights reserved).

Group work as an incentive for learning – students’ experiences of group work

PubMed Central

Hammar Chiriac, Eva

2014-01-01

Group work is used as a means for learning at all levels in educational systems. There is strong scientific support for the benefits of having students learning and working in groups. Nevertheless, studies about what occurs in groups during group work and which factors actually influence the students’ ability to learn is still lacking. Similarly, the question of why some group work is successful and other group work results in the opposite is still unsolved. The aim of this article is to add to the current level of knowledge and understandings regarding the essence behind successful group work in higher education. This research is focused on the students’ experiences of group work and learning in groups, which is an almost non-existing aspect of research on group work prior to the beginning of the 21st century. A primary aim is to give university students a voice in the matter by elucidating the students’ positive and negative points of view and how the students assess learning when working in groups. Furthermore, the students’ explanations of why some group work ends up being a positive experience resulting in successful learning, while in other cases, the result is the reverse, are of interest. Data were collected through a study-specific questionnaire, with multiple choice and open-ended questions. The questionnaires were distributed to students in different study programs at two universities in Sweden. The present result is based on a reanalysis and qualitative analysis formed a key part of the study. The results indicate that most of the students’ experiences involved group work that facilitated learning, especially in the area of academic knowledge. Three important prerequisites (learning, study-social function, and organization) for group work that served as an effective pedagogy and as an incentive for learning were identified and discussed. All three abstractions facilitate or hamper students’ learning, as well as impact their experiences with

Grade Point Average: Report of the GPA Pilot Project 2013-14

ERIC Educational Resources Information Center

Higher Education Academy, 2015

2015-01-01

This report is published as the result of a range of investigations and debates involving many universities and colleges and a series of meetings, presentations, discussions and consultations. Interest in a grade point average (GPA) system was originally initiated by a group of interested universities, progressing to the systematic investigation…

The Lagrangian Points

ERIC Educational Resources Information Center

Linton, J. Oliver

2017-01-01

There are five unique points in a star/planet system where a satellite can be placed whose orbital period is equal to that of the planet. Simple methods for calculating the positions of these points, or at least justifying their existence, are developed.

Three-dimensional displacement measurement of image point by point-diffraction interferometry

NASA Astrophysics Data System (ADS)

He, Xiao; Chen, Lingfeng; Meng, Xiaojie; Yu, Lei

2018-01-01

This paper presents a method for measuring the three-dimensional (3-D) displacement of an image point based on point-diffraction interferometry. An object Point-light-source (PLS) interferes with a fixed PLS and its interferograms are captured by an exit pupil. When the image point of the object PLS is slightly shifted to a new position, the wavefront of the image PLS changes. And its interferograms also change. Processing these figures (captured before and after the movement), the wavefront difference of the image PLS can be obtained and it contains the information of three-dimensional (3-D) displacement of the image PLS. However, the information of its three-dimensional (3-D) displacement cannot be calculated until the distance between the image PLS and the exit pupil is calibrated. Therefore, we use a plane-parallel-plate with a known refractive index and thickness to determine this distance, which is based on the Snell's law for small angle of incidence. Thus, since the distance between the exit pupil and the image PLS is a known quantity, the 3-D displacement of the image PLS can be simultaneously calculated through two interference measurements. Preliminary experimental results indicate that its relative error is below 0.3%. With the ability to accurately locate an image point (whatever it is real or virtual), a fiber point-light-source can act as the reticle by itself in optical measurement.

LiDAR Point Cloud and Stereo Image Point Cloud Fusion

DTIC Science & Technology

2013-09-01

LiDAR point cloud (right) highlighting linear edge features ideal for automatic registration...point cloud (right) highlighting linear edge features ideal for automatic registration. Areas where topography is being derived, unfortunately, do...with the least amount of automatic correlation errors was used. The following graphic (Figure 12) shows the coverage of the WV1 stereo triplet as

The 3.2 Angstrom Resolution Structure of the Polymorphic Cowpea Chlorotic Mottle Virus Ribonucleoprotein Particle

NASA Astrophysics Data System (ADS)

Speir, Jeffrey Alan

Structural studies of the polymorphic cowpea chlorotic mottle virus have resulted in high resolution structures for two distinct icosahedral ribonucleoprotein particle conformations dependent upon whether acidic or basic pH conditions prevail. CCMV is stable below pH 6.5, however metal-free particles maintain a 10% increase in hydrodynamic volume at pH >=q 7.5. Identification of this swollen' form of CCMV, which can easily be disrupted with 1M NaCl, led to the first reassembly of an icosahedral virus in vitro from purified viral protein and RNA to form infectious particles, and its assembly has been the subject of biochemical and biophysical investigations for over twenty-five years. Under well defined conditions of pH, ionic strength and divalent metal ion concentration, CCMV capsid protein or capsid protein and RNA will reassemble to form icosahedral particles of various sizes, sheets, tubes, rosettes, and a variety of laminar structures which resemble virion structures from non-related virus families. Analysis of native particles at 3.2A resolution and swollen particles at 28A resolution has suggested that the chemical basis for the formation of polymorphic icosahedral and anisometric structures is: (i) hexamers formed of beta-barrel subunits stabilized by an unusual hexameric parallel beta structure made up of their N-termini, (ii) the location of protein-RNA interactions, (iii) divalent metal cation binding sites that regulate quasi-symmetrical subunit associations, (iv) charge repulsion across the same interfaces when lacking divalent metal ions at basic pH, which induces the formation of sixty 20A diameter portals for RNA release, and (v) a novel, C-terminal-based, subunit dimer assembly unit. The use of C- and N-terminal arms in CCMV has not been observed in other icosahedral RNA virus structures determined at near atomic resolution, however, their detailed interactions and roles in stabilizing the quaternary organization of CCMV are related to that found

The End of Points

ERIC Educational Resources Information Center

Feldman, Jo

2018-01-01

Have teachers become too dependent on points? This article explores educators' dependency on their points systems, and the ways that points can distract teachers from really analyzing students' capabilities and achievements. Feldman argues that using a more subjective grading system can help illuminate crucial information about students and what…

First-principles investigation of neutron-irradiation-induced point defects in B4C, a neutron absorber for sodium-cooled fast nuclear reactors

NASA Astrophysics Data System (ADS)

You, Yan; Yoshida, Katsumi; Yano, Toyohiko

2018-05-01

Boron carbide (B4C) is a leading candidate neutron absorber material for sodium-cooled fast nuclear reactors owing to its excellent neutron-capture capability. The formation and migration energies of the neutron-irradiation-induced defects, including vacancies, neutron-capture reaction products, and knocked-out atoms were studied by density functional theory calculations. The vacancy-type defects tend to migrate to the C–B–C chains of B4C, which indicates that the icosahedral cage structures of B4C have strong resistance to neutron irradiation. We found that lithium and helium atoms had significantly lower migration barriers along the rhombohedral (111) plane of B4C than perpendicular to this plane. This implies that the helium and lithium interstitials tended to follow a two-dimensional diffusion regime in B4C at low temperatures which explains the formation of flat disk like helium bubbles experimentally observed in B4C pellets after neutron irradiation. The knocked-out atoms are considered to be annihilated by the recombination of the close pairs of self-interstitials and vacancies.

Band warping, band non-parabolicity, and Dirac points in electronic and lattice structures

NASA Astrophysics Data System (ADS)

Resca, Lorenzo; Mecholsky, Nicholas A.; Pegg, Ian L.

2017-10-01

We illustrate at a fundamental level the physical and mathematical origins of band warping and band non-parabolicity in electronic and vibrational structures. We point out a robust presence of pairs of topologically induced Dirac points in a primitive-rectangular lattice using a p-type tight-binding approximation. We analyze two-dimensional primitive-rectangular and square Bravais lattices with implications that are expected to generalize to more complex structures. Band warping is shown to arise at the onset of a singular transition to a crystal lattice with a larger symmetry group, which allows the possibility of irreducible representations of higher dimensions, hence band degeneracy, at special symmetry points in reciprocal space. Band warping is incompatible with a multi-dimensional Taylor series expansion, whereas band non-parabolicities are associated with multi-dimensional Taylor series expansions to all orders. Still band non-parabolicities may merge into band warping at the onset of a larger symmetry group. Remarkably, while still maintaining a clear connection with that merging, band non-parabolicities may produce pairs of conical intersections at relatively low-symmetry points. Apparently, such conical intersections are robustly maintained by global topology requirements, rather than any local symmetry protection. For two p-type tight-binding bands, we find such pairs of conical intersections drifting along the edges of restricted Brillouin zones of primitive-rectangular Bravais lattices as lattice constants vary relatively to each other, until these conical intersections merge into degenerate warped bands at high-symmetry points at the onset of a square lattice. The conical intersections that we found appear to have similar topological characteristics as Dirac points extensively studied in graphene and other topological insulators, even though our conical intersections have none of the symmetry complexity and protection afforded by the latter more

Percolation analysis for cosmic web with discrete points

NASA Astrophysics Data System (ADS)

Zhang, Jiajun; Cheng, Dalong; Chu, Ming-Chung

2016-03-01

Percolation analysis has long been used to quantify the connectivity of the cosmic web. Unlike most of the previous works using density field on grids, we have studied percolation analysis based on discrete points. Using a Friends-of-Friends (FoF) algorithm, we generate the S-bb relation, between the fractional mass of the largest connected group (S) and the FoF linking length (bb). We propose a new model, the Probability Cloud Cluster Expansion Theory (PCCET) to relate the S-bb relation with correlation functions. We show that the S-bb relation reflects a combination of all orders of correlation functions. We have studied the S-bb relation with simulation and find that the S-bb relation is robust against redshift distortion and incompleteness in observation. From the Bolshoi simulation, with Halo Abundance Matching (HAM), we have generated a mock galaxy catalogue. Good matching of the projected two-point correlation function with observation is confirmed. However, comparing the mock catalogue with the latest galaxy catalogue from SDSS DR12, we have found significant differences in their S-bb relations. This indicates that the mock catalogue cannot accurately recover higher order correlation functions than the two-point correlation function, which reveals the limit of HAM method.

78 FR 55096 - Certain Point-to-Point Network Communication Devices and Products Containing Same; Institution of...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-09

... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-892] Certain Point-to-Point Network... sale within the United States after importation of certain point-to- point network communication... sale within the United States after importation of certain point-to- point network communication...