Renormalization of the axial-vector current in QCD

Following the method of Ioffe and Smilga, the propagation of the baryon current in an external constant axial-vector field is considered. The close similarity of the operator-product expansion with and without an external field is shown to arise from the chiral invariance of gauge interactions in perturbation theory. Several sum rules corresponding to various invariants both for the nucleon and the hyperons are derived. The analysis of the sum rules is carried out by two independent methods, one called the ratio method and the other called the continuum method, paying special attention to the nondiagonal transitions induced by the external field between the ground state and excited states. Up to operators of dimension six, two new external-field-induced vacuum expectation values enter the calculations. Previous work determining these expectation values from PCAC (partial conservation of axial-vector current) are utilized. Our determination from the sum rules of the nucleon axial-vector renormalization constant GA, as well as the Cabibbo coupling constants in the SU3-symmetric limit (ms=0), is in reasonable accord with the experimental values. Uncertainties in the analysis are pointed out. The case of broken flavor SU3 symmetry is also considered. While in the ratio method, the results are stable for variation of the fiducial interval of the Borel mass parameter over which the left-hand side and the right-hand side of the sum rules are matched, in the continuum method the results are less stable. Another set of sum rules determines the value of the linear combination 7F-5D to be ≊0, or D/(F+D)≊(7/12). .AE

EPR observation of phase transitions in calcium cadmium acetate hexahydrate: Using Mn2+ and Cu2+ ions as probe

Results of temperature dependence of EPR spectra of Mn2+ and Cu2+ ions doped calcium cadmium acetate hexahydrate (CaCd(CH3COO)4•6H2O) have been reported. The investigation has been carried out in the temperature range between room temperature ( 300 K) and liquid nitrogen temperature. A I-order phase transition at 146 ± 0.5 K has been confirmed. In addition a new II-order phase transition at 128 ± 1 K has been detected for the first time. There is evidence of large amplitude hindered rotations of CH3 groups which become frozen at 128 K. The incorporation of Cu2+ and Mn2+ probes at Ca2+ and Cd2+ sites respectively provide evidence that the phase transitions are caused by the molecular rearrangements of the common coordinating acetate groups between Ca2+ and Cd2+ sites. In contradiction to the previous reports of a change of symmetry from tetragonal to orthorhombic below 140 K, the symmetry of the host is concluded to remain tetragonal in all the three observed phases between room temperature and liquid nitrogen temperature.

The crystal structure of the amino-terminal pentapeptide of suzukacillin. Occurrence of a four-fold peptide helix

The monohydrate of the protected amino-terminal pentapeptide of suzukacillin, t-butoxycarbonyl--aminoisobutyryl-L-prolyl-L-valyl--aminoisobutyryl-L-valine methyl ester, C29H51N5O8, crystallizes in the orthorhombic space group P212121 with a= 10.192, b= 10.440, c= 32.959 Å, and Z= 4. The structure has been solved by direct methods and refined to an R value of 0.101 for 1 827 observed reflections. The molecule exists as a four-fold helix with a pitch of 5.58 Å. The helix is stabilised by N–H O hydrogen bonds, two of the 51 type (corresponding to the -helix) and the third of the 41 type (310 helix). The carbonyl oxygen of the amino-protecting group accepts two hydrogen bonds, one each from the amide NH groups of the third (41) and fourth (51) residues. The remaining 51 hydrogen bond is between the two terminal residues. The lone water molecule in the structure is hydrogen bonded to carbonyl oxygens of the prolyl residue in one molecule and the non-terminal valyl residue in a symmetry-related molecule.

Structure of 7-methyl-1(2)a,1(6)a,3(4)a-trihomocubane-1(6)a,3(4)a-dione,star-c12h12o2- a case of enantiomeric and rotational disorder

M r = 188.22, monoclinic, P21/n, a = 6.219 (2), b= 10.508 (2), c=7.339 (1)A, t= 107.64 (2) °, V= 457 ,/k 3, Z = 2, D m - - 1.360 (3), D x = 1.366 (2)Mgm -3, ~,(MoKa) = 0.7107/~, #= 0.053 mm -I, F(000) = 200, T= 293 K. Final R = 5.8% for 614 significant reflections. The molecule, which does not possess a centre of symmetry, occupies a crystallographic centre of symmetry because of the statistical enantiomeric and rotational disorder. Latticeenergy calculations, based on van der Waals attractive and repulsive potentials, clearly show minima at the observed disordered positions.

A large orthotropic plate with misfit pin under arbitrarily oriented biaxial loading

The problem of misfit (interference or clearance) pin in a large orthotropic plate was solved earlier by the authors for biaxial loading in the principal directions of orthotropy. Here, a more general case of arbitrarily oriented loading is considered. The most important aspect of the problem studied is the partial contact at the pin-hole interface. The solution is obtained by extending the use of ‘inverse technique’ which was successfully applied earlier by the authors to problems of pins in isotropic and orthotropic domains. The loss of symmetry because of the arbitrary orientation of loading makes the problem more complex. Additional parameters are then involved in the inversion of the problem for the solution. Numerical results are presented primarily for a smooth interference fit pin in a typical orthotropic plate.

Synthesis, characterization and X-ray structure of hexahydrazinium diuranyl pentaoxalate dihydrate, (N2H5)6(UO2)2(C2O4)5·2H2O

A new hydrazinium uranyl oxalate complex (N2H5)6[(UO2)2(C2O4)5]·2H2O has been prepared and characterized by chemical analysis, infrared, visible spectra and TG-DTA. The single crystal X-ray structure of the complex shows the presence of discrete N2H5+ cations, water molecules and [(UO2)2(C2O4)5]6− anions. In the anion, the linear uranyl groups are coordinated by two chelating bidentate oxalates and one bridging oxalate which lies on the center of symmetry between the two uranyl groups. The coordination polyhedron around each uranium atom is approximately a pentagonal bipyramid.

Technicolor

The need for reexamination of the standard model of strong, weak, and electromagnetic interactions is discussed, especially with regard to 't Hooft's criterion of naturalness. It has been argued that theories with fundamental scalar fields tend to be unnatural at relatively low energies. There are two solutions to this problem: (i) a global supersymmetry, which ensures the absence of all the naturalness-violating effects associated with scalar fields, and (ii) composite structure of the scalar fields, which starts showing up at energy scales where unnatural effects would otherwise have appeared. With reference to the second solution, this article reviews the case for dynamical breaking of the gauge symmetry and the technicolor scheme for the composite Higgs boson. This new interaction, of the scaled-up quantum chromodynamic type, keeps the new set of fermions, the technifermions, together in the Higgs particles. It also provides masses for the electroweak gauge bosons W± and Z0 through technifermion condensate formation. In order to give masses to the ordinary fermions, a new interaction, the extended technicolor interaction, which would connect the ordinary fermions to the technifermions, is required. The extended technicolor group breaks down spontaneously to the technicolor group, possibly as a result of the "tumbling" mechanism, which is discussed here. In addition, the author presents schemes for the isospin breaking of mass matrices of ordinary quarks in the technicolor models. In generalized technicolor models with more than one doublet of technifermions or with more than one technicolor sector, we have additional low-lying degrees of freedom, the pseudo-Goldstone bosons. The pseudo-Goldstone bosons in the technicolor model of Dimopoulos are reviewed and their masses computed. In this context the vacuum alignment problem is also discussed. An effective Lagrangian is derived describing colorless low-lying degrees of freedom for models with two technicolor sectors in the combined limits of chiral symmetry and large number of colors and technicolors. Finally, the author discusses suppression of flavor-changing neutral currents in the extended technicolor models.

Electron and x-ray diffraction studies on Al86Fe14, Al82Fe18 and Al75Fe25 quasicrystals

Electron and x-ray diffraction experiments on the metlt-spun Al100−x Fe x (x=14, 18, 25) alloys are carried out. It is observed that all the melt-spun alloys possessing the quasi-crystalline phases have icosahedral point-group symmetry.

Development of special fastener elements

A special finite element (FASNEL) is developed for the analysis of a neat or misfit fastener in a two-dimensional metallic/composite (orthotropic) plate subjected to biaxial loading. The misfit fasteners could be of interference or clearance type. These fasteners, which are common in engineering structures, cause stress concentrations and are potential sources of failure. Such cases of stress concentration present considerable numerical problems for analysis with conventional finite elements. In FASNEL the shape functions for displacements are derived from series stress function solutions satisfying the governing difffferential equation of the plate and some of the boundary conditions on the hole boundary. The region of the plate outside FASNEL is filled with CST or quadrilateral elements. When a plate with a fastener is gradually loaded the fastener-plate interface exhibits a state of partial contact/separation above a certain load level. In misfit fastener, the extent of contact/separation changes with applied load, leading to a nonlinear moving boundary problem and this is handled by FASNEL using an inverse formulation. The analysis is developed at present for a filled hole in a finite elastic plate providing two axes of symmetry. Numerical studies are conducted on a smooth rigid fastener in a finite elastic plate subjected to uniaxial loading to demonstrate the capability of FASNEL.

An absolute method for the determination of surface tension of liquids using pendent drop profiles

Drop formation at conical tips which is of relevance to metallurgists is investigated based on the principle of minimization of free energy using the variational approach. The dimensionless governing equations for drop profiles are computer solved using the fourth order Runge-Kutta method. For different cone angles, the theoretical plots of XT and ZT vs their ratio, are statistically analyzed, where XT and ZT are the dimensionless x and z coordinates of the drop profile at a plane at the conical tip, perpendicular to the axis of symmetry. Based on the mathematical description of these curves, an absolute method has been proposed for the determination of surface tension of liquids, which is shown to be preferable in comparison with the earlier pendent-drop profile methods.

Toiminta ja tarkoite : Tutkimus suomen pronominista

The study describes the use and meaning of the Finnish demonstrative pronouns, focus being on the pronoun "tämä" (roughly 'this'). The Finnish demonstrative system is a three way one, the other two demonstratives are "tuo" ('that') and "se" ('it'). The data consisted of 12 half hours of video- and tape-recorded face-to-face and telephone conversations. The method for the study was ethnomethodological conversation analysis (CA); in addition to CA, the theoretical framework consisted of functional linguistics and linguistic anthropology. First, the study dealt with the syntactic distribution of the three demonstratives. The pronouns were analysed according to whether they are before or after the verb, and whether they compose an NP on their own or are determinants of a lexical NP. The study suggested that the form and the placement of the NP presents the referent as continuous/discontinuous or given/new. Givenness of a referent was defined as "identified adequately for the purposes of the on-going action". The so-called dislocated utterances were considered separately. It was found that left-dislocations are used for inserting referents in a particular relation to the on-going activity. Right-dislocations offer a solution for the sometimes competing motivations of newness and continuity: they are used for securing the identifiability of a referent that is implied to be continuous. Second, the study focussed on analysing the meaning of the pronouns according to three dimensions of reference: referential, indexical and relational. It was found that the demonstratives can organize interactional or spatial context. When organizing interactional context, the demonstrative pronouns express the role of identifying the referent in relation to the on-going activity. The pronoun "tämä" expresses that the referent is referentially open and the characterization of the referent is given in the on-going turn. Furthermore, it expresses asymmetry of the indexical ground: it expresses that the participants of a conversation do not share a mutual understanding of the activity at that particular time. In addition, the referent of the pronoun "tämä" is central for understanding the on-going action. Centrality could be understood as the relational feature of the pronoun. However, it is a consequence of the referential and indexical features of "tämä". The pronoun "tuo" also expresses referential openness, but it implies indexical symmetry. The pronoun "se" implies that the referent is known enough, and implies indexical symmetry. When used spatially, the pronouns may refer to a physical space or to a situation. They express or imply that the speaker is inside or outside the referent. The pronoun "tämä" implies inclusion, and the pronoun "tuo" expresses exclusion.

Nonverbal predication in Erzya : Studies on morphosyntactic variation and part of speech distinctions

This dissertation consists of four articles and an introduction. The five parts address the same topic, nonverbal predication in Erzya, from different perspectives. The work is at the same time linguistic typology and Uralic studies. The findings based on a large corpus of empirical Erzya data, which was collected using several different methods and included recordings of the spoken language, made it possible for the present study to apply, then test and finally discuss the previous theories based on cross-linguistic data. Erzya makes use of multiple predication patterns which vary from totally analytic to the morphologically very complex. Nonverbal predicate clause types are classified on the basis of propositional acts in clauses denoting class-membership, identity, property and location. The predicates of these clauses are nouns, adjectives and locational expressions, respectively. The following three predication strategies in Erzya nonverbal predication can be identified: i. the zero-copula construction, ii. the predicative suffix construction and iii. the copula construction. It has been suggested that verbs and nouns cannot be clearly distinguished on morphological grounds when functioning as predicates in Erzya. This study shows that even though predicativity must not be considered a sufficient tool for defining parts of speech in any language, the Erzya lexical classes of adjective, noun and verb can be distinguished from each other also in predicate position. The relative frequency and degree of obligation for using the predicative suffix construction decreases when moving left to right on the scale verb adjective/locative noun ( identificational statement). The predicative suffix is the main pattern in the present tense over the whole domain of nonverbal predication in Standard Erzya, but if it is replaced it is most likely to be with a zero-copula construction in a nominal predication. This study exploits the theory of (a)symmetry for the first time in order to describe verbal vs. nonverbal predication. It is shown that the asymmetry of paradigms and constructions differentiates the lexical classes. Asymmetrical structures are motivated by functional level asymmetry. Variation in predication as such adds to the complexity of the grammar. When symmetric structures are employed, the functional complexity of grammar decreases, even though morphological complexity increases. The genre affects the employment of predication strategies in Erzya. There are differences in the relative frequency of the patterns, and some patterns are totally lacking from some of the data. The clearest difference is that the past tense predicative suffix construction occurs relatively frequently in Standard Erzya, while it occurs infrequently in the other data. Also, the predicative suffixes of the present tense are used more regularly in written Standard Erzya than in any other genre. The genre also affects the incidence of the translative in uľ(ń)ems copula constructions. In translations from Russian to Erzya the translative case is employed relatively frequently in comparison to other data. This study reveals differences between the two Mordvinic languages Erzya and Moksha. The predicative suffixes (bound person markers) of the present tense are used more regularly in Moksha in all kinds of nonverbal predicate clauses compared to Erzya. It should further be observed that identificational statements are encoded with a predicative suffix in Moksha, but seldom in Erzya. Erzya clauses are more frequently encoded using zero-constructions, displaying agreement in number only.

An RNS based transform Architecture for H.264/AVC

This paper presents the architecture and the VHDL design of an integer 2-D DCT used in the H.264/AVC. The 2-D DCT computation is performed by exploiting it’s orthogonality and separability property. The symmetry of the forward and inverse transform is used in this implementation. To reduce the computation overhead for the addition, subtraction and multiplication operations, we analyze the suitability of carry-free position independent residue number system (RNS) for the implementation of 2-D DCT. The implementation has been carried out in VHDL for Altera FPGA. We used the negative number representation in RNS, bit width analysis of the transforms and dedicated registers present in the Logic element of the FPGA to optimize the area. The complexity and efficiency analysis show that the proposed architecture could provide higher through-put.

Raman Spectra of NaLa(MoO,), Single Crystal

The Raman spectra of NaLa(MoO4)2 single crystal have been recorded and interpreted on the basis of C4h symmetry. The observed fundamentals (internal and external) have been assigned unambiguously with the help of polarization data. All the group theoretically predicted Raman active fundamentals have been observed.

Mesoscale description of an asymmetric lamellar phase

The relationship between the parameters in a description based on a mesoscale free energy functional for the concentration field and the macroscopic properties, such as the bending and compression moduli and the permeation constant, are examined for an asymmetric lamellar phase where the mass fractions of the hydrophobic and hydrophilic parts are not equal. The difference in the mass fractions is incorporated using a cubic term in the free energy functional, in addition to the usual quadratic and quartic terms in the Landau–Ginsburg formulation. The relationship between the coefficient of the cubic term and the difference in the mass fractions of the hydrophilic and hydrophobic parts is obtained. For a lamellar phase, it is important to ensure that the surface tension is zero due to symmetry considerations. The relationship between the parameters in the free energy functional for zero surface tension is derived. When the interface between the hydrophilic and hydrophobic parts is diffuse, it is found that the bending and compression moduli, scaled by the parameters in the free energy functional, do increase as the asymmetry in the bilayer increases. When the interface between the hydrophilic and hydrophobic parts is sharp, the scaled bending and compression moduli show no dependence on the asymmetry in the bilayer. The ratio of the permeation constant in between the water and bilayer in a molecular description and the Onsager coefficient in the mesoscale description is O(1) for both sharp and diffuse interfaces and it increases as the difference in the mass fractions is increased.