Three New Species of Hyperaspis from Eastern North America (Coleoptera: Coccinellidae)

Excerpt: A number of apparently related species, including the three which are newly described in this paper, belong to the large binotata group of Dobzhansky (1941). It has been found necessary to re-examine this group and to divide it into smaller, more homogeneous species clusters. These new species clusters may indicate more clearly the relationships of the species involved

Pre-pausal devoicing and glottalisation in varieties of the south-western Arabian peninsula

A wide range of modern Arabic dialects exhibit devoicing in pre-pausal (utterance-final) position. These include Cairene [20], Gulf Arabic, San’ani [8], [18], Manaxah [19], Central Highland Yemeni dialects [1], Rijal Alma‘ (Asiri p.c.), Central Sudanese (Dickins p.c.), Çukurova [15], Kinderib [9], E. Fayyum [2]. In some dialects, pausal devoicing is reported to be accompanied by aspiration (e.g. Cairene, [19]), in others by glottalisation (e.g. Fayyum, [2]; Manaxah, [18]; San’ani, [8], [18]). As preliminary work to a study of pausal phenomena in the south-western Arabian Peninsula, we examine data from two Arabic dialects – San’ani (SA), spoken in the Old City of San’a, Yemen, and the Asiri dialect of Rijal Alma‘ (RA) – and from Mehriyōt, an eastern dialect of the modern south Arabian language, Mehri, spoken in Yemen. We begin by presenting a summary of pausal phenomena in SA. We then consider the behaviour of final oral stops – velar, coronal and labial – final coronal fricatives, final nasals and liquids, and final vowels. Initial comparison with data from RA and Mehriyōt indicates that utterance-final devoicing is more advanced in SA than in the other varieties, and involves a greater range of segment types. The first set of pausal examples were extracted from Watson’s recordings of spontaneous SA monologues on the Semitic Spracharchiv. The main speaker is a young semi educated woman.1 Those forms which exist as lexemes in RA, plus lexemes involving similar pre-pausal segments in comparable syllable types, were recorded utterance-finally by Yahya Asiri, a native speaker of RA. Pausal forms for Mehriyōt were extracted from the late Alexander Sima’s recordings of spontaneous speech on the Semitic sound archive [16]. The Mehriyōt speaker is a low- to semi-educated early middle-aged man. Data were analysed using the phonetic analysis programme PRAAT (www.praat.org)

Microstructural characteristics of diecast AlMgSiMn alloy

Solidification and microstructural characteristics of Al-5wt.%Mg-1.5wt.%Si-0.6wt.%Mn- 0.2wt.%Ti alloy have been investigated in high pressure die casting. The average size of dendrites and fragmented dendrites of the primary α-Al phase formed in the shot sleeve is 43μm, and the globular α-Al grains formed inside the die cavity is 7.5μm. Solidification inside the die cavity also forms the lamellar Al-Mg2Si eutectic phase and the Fe-rich intermetallics. The size of the eutectic cells is about 10μm, in which the lamellar α-Al phase is 0.41μm thick. The Fe-rich intermetallic compound exhibits a compact morphology and is less than 2μm. Calculations using the Mullins and Sekerka stability criterion reveal that the solidification of the primary α-Al phase inside the die cavity has completed before the spherical α-Al globules begin to lose their stability, but the α-Al grains formed in the shot sleeve exceed the limit of spherical growth and therefore exhibit a dendritic morphology

Leading order infrared quantum chromodynamics in Coulomb gauge

A truncation scheme for the Dyson-Schwinger equations of quantum chromodynamics in Coulomb gauge within the first order formalism is presented. The truncation is based on an Ansatz for the Coulomb kernel occurring in the action. Results at leading loop order and in the infrared are discussed for both the Yang-Mills and quark sectors. It is found that the resulting equations for the static gluon and quark propagators agree with those derived in a quasi-particle approximation to the canonical Hamiltonian approach. Moreover, a connection to the heavy quark limit is established. The equations are analyzed numerically and it is seen that in both the gluonic and quark sectors, a nontrivial dynamical infrared mass scale emerges.Comment: 27 pages, 11 figure

Microstructural evolution and solidification behavior of Al-Mg-Si alloy in high-pressure die casting

Copyright @ 2013 ASM International. This paper was published in Metallurgical and Materials Transactions A, 44A(7), 3185 - 3197 and is made available as an electronic reprint with the permission of ASM International. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplications of any material in this paper for a fee or for commercial purposes, or modification of the content of this paper are prohibited.Microstructural evolution and solidification behavior of Al-5 wt pct Mg-1.5 wt pct Si-0.6 wt pct Mn-0.2 wt pct Ti alloy have been investigated using high-pressure die casting. Solidification commences with the formation of primary a-Al phase in the shot sleeve and is completed in the die cavity. The average size of dendrites and fragmented dendrites of the primary a-Al phase formed in the shot sleeve is 43 lm, and the globular primary a-Al grains formed inside the die cavity is at a size of 7.5 lm. Solidification inside the die cavity also forms the lamellar Al-Mg2Si eutectic phase and the Fe-rich intermetallics. The size of the eutectic cells is about 10 lm, in which the lamellar a-Al phase is 0.41 lm thick. The Fe-rich intermetallic compound exhibits a compact morphology and is less than 2 lm with a composition of 1.62 at. pct Si, 3.94 at. pct Fe, and 2.31 at. pct Mn. A solute-enriched circular band is always observed parallel to the surface of the casting. The band zone separates the outer skin region from the central region of the casting. The solute concentration is consistent in the skin region and shows a general drop toward the center inside the band for Mg and Si. The peak of the solute enrichment in the band zone is much higher than the nominal composition of the alloy. The die casting exhibits a combination of brittle and ductile fracture. There is no significant difference on the fracture morphology in the three regions. The band zone is not significantly detrimental in terms of the fracture mechanism in the die casting. Calculations using the Mullins and Sekerka stability criterion reveal that the solidification of the primary a-Al phase inside the die cavity has been completed before the spherical a-Al globules begin to lose their stability, but the a-Al grains formed in the shot sleeve exceed the limit of spherical growth and therefore exhibit a dendritic morphologyEPSRC and JL

A homing receptor-IgG chimera as a probe for adhesive ligands of lymph node high endothelial venules.

The binding of lymphocytes to high endothelial venules (HEV) within peripheral lymph nodes (pln) is thought to be mediated by a lectinlike adhesion molecule termed the pln homing receptor (pln HR). The cloning and sequencing of cDNAs encoding both murine and human pln HR revealed that these adhesion molecules contain protein motifs that are homologous to C-type or calcium dependent lectin domains as well as to epidermal growth factor (egf) and complement-regulatory protein domains. We have produced a novel, antibody-like form of the murine HR by joining the extracellular region of the receptor to a human IgG heavy chain. This antibody-like molecule is capable of recognizing carbohydrates, blocking the binding of lymphocytes to pln HEV, and serving as a histochemical reagent for the staining of pln HEV. This murine HR-IgG chimera should prove useful in analyzing the distribution of the HR ligand(s) in normal as well as in inflammatory states

The complement binding-like domains of the murine homing receptor facilitate lectin activity.

The leukocyte homing receptor (HR), the endothelial leukocyte adhesion molecule, and gmp140/platelet activation-dependent granule membrane protein are members of a family of adhesion molecules, termed the lectin cell adhesion molecules (LEC-CAMS) which are unified by a multi-domain structure containing a lectin motif, an epidermal growth factor-like (egf) motif, and variable numbers of a complement binding-like (CB) motif. Previous data have indicated a predominant role for the lectin motif in cell adhesion directed by the LEC-CAMS, although the egf-like domain of the HR may also play a potential role in cell binding. While the role(s) of the CB domains in the LEC-CAMS is currently not understood, they have been hypothesized to act as rigid spacers or stalks for lectin and perhaps, egf domain presentation. In this paper, we analyze the functional characteristics of murine HR-IgG chimeras containing the lectin, lectin plus egf, and lectin plus egf plus CB domains. The Mel 14 mAb, an adhesion blocking antibody which recognizes a conformational determinant in the N-terminus of the HR lectin domain, shows a significantly decreased affinity for a HR construct which lacks the CB motifs, consistent with the possibility that the CB domains are involved with lectin domain structure. In agreement with this conjecture, HR mutants lacking the CB domains show a profound decrease in lectin-specific interaction with the carbohydrate polyphosphomannan ester, suggesting that the changes in Mel 14 affinity for the lectin domain are reflected in lectin functionality. Various assays investigating the interactions between the HR deletion mutants and the peripheral lymph node high endothelium, including cell blocking, immunohistochemical staining, and radioactively labeled ligand binding, all showed that removal of the CB domains results in a lack of HR adhesive function. These results imply that the CB domains of the HR, and, by analogy, the other members of the LEC-CAM family, may play important structural roles involving induction of lectin domain conformation and resultant functionality

An Investigation, Using Standard Experimental Techniques, to Determine FLCs at Elevated Temperature for Aluminium Alloys

An experimental procedure has been developed for the determination of FLCs at elevated temperatures. The GOM ARGUS system was employed for measuring surface strain based on pre-applied grids (pattern), and limit strains were determined according to the ISO 12004-2:2008 standard. Forming limit curves (FLCs) have been determined for AA5754 under warm forming conditions in an isothermal environment. The tests were carried out at various temperatures up to 300oC and forming speeds ranging from 5 – 300 mm s-1 . Results reveal the significant effect of both temperature and forming speed on FLCs of AA5754. Formability increases with increasing temperature above 200oC. Formability also increases with decreasing speed. The presented FLC results show that the best formability exists at low forming speed and the high temperature end of the warm forming range

Large Sample Asymptotic Theory of Tests for Uniformity on the Grassmann Manifold

AbstractThe Grassmann manifold Gk,m − k consists of k-dimensional linear subspaces V in Rm. To each V in Gk,m − k, corresponds a unique m × m orthogonal projection matrix P idempotent of rank k. Let Pk,m − k denote the set of all such orthogonal projection matrices. We discuss distribution theory on Pk,m − k, presenting the differential form for the invariant measure and properties of the uniform distribution, and suggest a general family F(P) of non-uniform distributions. We are mainly concerned with large sample asymptotic theory of tests for uniformity on Pk,m − k. We investigate the asymptotic distribution of the standardized sample mean matrix U taken from the family F(P) under a sequence of local alternatives for large sample size n. For tests of uniformity versus the matrix Langevin distribution which belongs to the family F(P), we consider three optimal tests-the Rayleigh-style, the likelihood ratio, and the locally best invariant tests. They are discussed in relation to the statistic U, and are shown to be approximately, near uniformity, equivalent to one another. Zonal and invariant polynomials in matrix arguments are utilized in derivations