Evidence for the reliability and validity, but not the practical utility of the two-factor Consideration of Future Consequences Scale-14

Researchers have proposed 1-factor, 2-factor, and bifactor solutions to the 12-item Consideration of Future Consequences Scale (CFCS-12). In order to overcome some measurement problems and to create a robust and conceptually useful two-factor scale the CFCS-12 was recently modified to include two new items and to become the CFCS-14. Using a University sample, we tested four competing models for the CFCS-14: (a) a 12-item unidimensional model, (b) a model fitted for two uncorrelated factors (CFC-Immediate and CFC-Future), (c) a model fitted for two correlated factors (CFC-I and CFC-F), and (d) a bifactor model. Results suggested that the addition of the two new items has strengthened the viability of a two factor solution of the CFCS-14. Results of linear regression models suggest that the CFC-F factor is redundant. Further studies using alcohol and mental health indicators are required to test this redundancy.

Multiple configurations of the two excess 4f electrons on defective CeO2(111):Origin and implications

Density-functional theory calculations have been carried out to systematically study single surface oxygen vacancies on CeO2(111). It is surprisingly found that multiple structures with the two excess electrons localized at different positions can exist. We show that the origin of the multiconfigurations of 4f electrons is a result of geometric relaxation on the surface and strong localization characteristic of 4f electrons in ceria. The importance of 4f electron structures is also presented and discussed. These results may possess implications for our understanding of materials with f electrons.

A non-LTE analysis of the spectra of two narrow lined main sequence stars in the SMC

An analysis of high-resolution VLT/UVES spectra of two B-type main sequence stars, NGC 346-11 and AV 304, in the Small Magellanic Cloud (SMC), has been undertaken, using the non-LTE tlusty model atmospheres to derive the stellar parameters and chemical compositions of each star. The chemical compositions of the two stars are in reasonable agreement. Moreover, our stellar analysis agrees well with earlier analyses of H II regions. The results derived here should be representative of the current base-line chemical composition of the SMC interstellar medium as derived from B-type stars.

Nonharmonic transverse vibration of the H-bonded molecules and the THz spectra in ice and water

A nonlinear equation of motion is found for the dimer comprising two charged H2O molecules. The THz dielectric response to nonharmonic vibration of a nonrigid dipole, forming the hydrogen bond (HB), is found in the direction transverse to this bond. An explicit expression is derived for the autocorrelator that governs the spectrum generated by transverse vibration (TV) of such a dipole. This expression is obtained by analytical solution of the truncated set of recurrence equations. The far infrared (FIR) spectra of ice at the temperature - 7 degrees C are calculated. The wideband, in the wavenumber (frequency) v range 0... 100.0 cm(-1), spectra are obtained for liquid water at room temperature and for supercooled water at -5.6 degrees C. All spectra are represented in terms of the complex permittivity epsilon(v) and the absorption coefficient alpha(v). The obtained analytical formula for epsilon comprises the term epsilon(perpendicular to) pertinent to the studied TV mechanism with three additional terms Delta epsilon(q), Delta epsilon(mu), and epsilon(or) arising, respectively, from: elastic harmonic vibration of charged molecules along the H-bond; elastic reorientation of HB permanent dipoles; and rather free libration of permanent dipoles in 'defects' of water/ice structure. The suggested TV-dielectric relaxation mechanism allows us: (a) to remove the THz 'deficit' of loss epsilon" inherent in previous theoretical studies; (b) to explain the THz loss and absorption spectra in supercooled (SC) water; and (c) to describe, in agreement with the experiment, the low- and high-frequency tails of the two bands of ice H2O located in the range 10...300 cm(-1). Specific THz dielectric properties of SC water are ascribed to association of water molecules, revealed in our study by transverse vibration of HB charged molecules. (C) 2006 Published by Elsevier B.V.

Insights into the binding and activation sites of the receptors for cholecystokinin and gastrin

CCK receptors represent potential targets in a number of diseases. Knowledge of CCK receptor binding sites is a prerequisite for the understanding of the molecular basis for their ligand recognition, partial agonism, ligand-induced trafficking of signalling. In the current paper, we report studies from our laboratory and others which have provided new data on the molecularbasis of the pharmacology and functioning of CCK1 and CCK2 receptors. It has been shown that: 1) homologous regions of the two receptors are involved in the binding site of CCK, however, positioning of CCK slightly differs in agreement with distinct phannacophores of CCK toward the two receptors and receptor sequence variations; 2) Binding sites of most of non-peptide agonists/ antagonist are buried in the pocket formed by transmembrane helices and overlap that of CCK; Aromatic amino acids within and near the binding site, especially in helix VI, are involved in receptor activation; 4) Like for other members of family A of G-protein coupled receptors, residues of the binding sites as well as of conserved motifs such as E/DRY, NPXXY are crucial for receptor activation. (c) 2007 Elsevier B.V. All rights reserved.

IONIC COMPOSITION OF THE LIVER FLUKE FASCIOLA-HEPATICA FROM DIFFERENT MAMMALIAN HOSTS AND COMPARISON WITH HOST BILE

A qualitative analysis of the cationic profile of bovine and ovine biles and of bovine, ovine and rat liver flukes has been carried out by DC are emission spectrography. A quantitative assessment of the concentrations of Na+, K+, Ca2+ and Mg2+ ions in bovine, ovine and rat flukes has been determined by atomic absorption spectrophotometry. The levels of these ions in bovine and ovine bile samples have also been assessed and compared with those of Hedon-Heig saline. The ionic composition of the two biles is similar and the concentration of each ion is greater than that in Hedon-Heig saline. Despite the similarity in biles, ion levels in bovine flukes are generally higher than those in ovine flukes. Ion levels in rat flukes are different again but show closer similarity to those in bovine, not ovine, flukes. The results are discussed in relation to the proposed operation of the osmoregulatory system in the fluke.

ULTRASTRUCTURAL-LOCALIZATION OF FMRFAMIDE-IMMUNOREACTIVITY AND PANCREATIC POLYPEPTIDE-IMMUNOREACTIVITY WITHIN THE CENTRAL-NERVOUS-SYSTEM OF THE LIVER FLUKE, FASCIOLA-HEPATICA (TREMATODA, DIGENEA)

A post-embedding immunogold technique was used to examine the subcellular distribution of immunoreactivities to the invertebrate peptide, FMRFamide, and to vertebrate pancreatic polypeptide (PP) within the central nervous system of the trematode, Fasciola hepatica. Gold labeling of peptide was localised exclusively over both dense-cored and ellipsoidal electron-dense vesicles (with a homogeneous matrix) present within nerve cell bodies, small and 'giant' nerve processes of the neuropile in the cerebral ganglia and transverse commissure, as well as in the main longitudinal nerve cords. Double labeling demonstrated an apparent co-localisation of FMRFamide and PP immunoreactivities in the same dense-cored vesicles, although populations of ellipsoidal electron-dense vesicles that labeled solely for FMRFamide were also evident. Antigen pre-absorption studies indicated little, if any, cross-reactivity of the two antisera.

FASCIOLA-HEPATICA - THE EFFECT OF THE MICROTUBULE INHIBITORS COLCHICINE AND TUBULOZOLE-C ON THE ULTRASTRUCTURE OF THE ADULT FLUKE

The effect of the microtubule inhibitors colchicine (1 x 10(-3) M) and tubulozole-C(1 x 10(-6) M) on the ultrastructure of adult Fasciola hepatica has been determined in vitro by transmission electron microscopy (TEM), using both intact flukes and tissue-slice material. With colchicine treatment, the apical membrane of the tegument became increasingly convoluted and blebbed, while accumulations of T1 secretory bodies occurred in the basal region of the syncytium, leading to progressively fewer secretory bodies in the syncytium. In the tegumental cells there were distinct accumulations of Tl secretory bodies around the Golgi complexes, which remained active for up to 12 h incubation. Tubulozole-treated flukes showed more severe effects, with initial accumulations of secretory bodies, both at the tegumental apex and base. This was followed in the later time-periods by the sloughing of the tegumental syncytium. In the underlying tegumental cells, the granular endoplasmic reticulum (GER) cisternae were swollen and disrupted, becoming concentrated around the nucleus. The Golgi complexes were dispersed to the periphery of the cells and gradually disappeared from the cytoplasm. After treatment with both drugs, the cell population in the vitelline follicles was altered, with an abnormally large proportion of stem cells and relatively few intermediate type 1 cells. The nurse cell cytoplasm became fragmented and was no longer in contact with the vitelline cells, while the shell globule clusters within the intermediate type 2 and mature cells were loosely packed. In the mature vitelline cells, 'yolk' globules and glycogen deposits became fewer than normal and lipid droplets were observed. The results are discussed in relation to the different modes of action of the two drugs and potential significance of this to anthelmintic (benzimidazole) therapy.

IMMUNOELECTRON MICROSCOPIC STUDIES OF REGULATORY PEPTIDES IN THE NERVOUS-SYSTEM OF THE MONOGENEAN PARASITE, DICLIDOPHORA-MERLANGI

Specific antisera, directed against the highly conserved C-terminal hexapeptide amide of mammalian pancreatic polypeptide (PP) and the invertebrate peptide FMRFamide, have been used in conjunction with post-embedding, IgG-conjugated colloidal gold immunostaining to demonstrate peptide immunoreactivity at subcellular level in the nervous system of adult Diclidophora merlangi. Gold labelling revealed that immunoreactivity for PP and FMRFamide was localized exclusively in dense-cored vesicles occupying the majority of axons in the central nervous system. Double-labelling demonstrated an apparent co-localization of PP and FMRFamide in the same dense-cored vesicles. Antigen preabsorption experiments indicated cross-reactivity of the two antisera as unlikely, and that some if not all of the PP/FMRFamide immunostaining in the parasite was due to a neuropeptide F-like peptide.

Note on the single-shock solutions of the Korteweg-de Vries-Burgers equation

The well-known shock solutions of the Korteweg-de Vries-Burgers equation are revisited, together with their limitations in the context of plasma (astro)physical applications. Although available in the literature for a long time, it seems to have been forgotten in recent papers that such shocks are monotonic and unique, for a given plasma configuration, and cannot show oscillatory or bell-shaped features. This uniqueness is contrasted to solitary wave solutions of the two parent equations (Korteweg-de Vries and Burgers), which form a family of curves parameterized by the excess velocity over the linear phase speed.

The failure of generalized gradient approximations (GGAs) and meta-GGAs for the two-center three-electron bonds in He-2(+), (H2O)(2)(+), and (NH3)(2)(+)

The radical cations He-2(+) (H2O)(2)(+), and (NH3)(2)(+) with two-center three-electron A-A bonds are investigated at the configuration interaction (CI), accurate Kohn-Sham (KS), generalized gradient approximation (GGA), and meta-GGA levels. Assessment of seven different GGA and six meta-GGA methods shows that the A(2)(+) systems remain a difficult case for density functional theory (DFT). All methods tested consistently overestimate the stability of A(2)(+): the corresponding D-e errors decrease for more diffuse valence densities in the series He-2(+) > (H2O)(2)(+) > (NH3)(2)(+). Upon comparison to the energy terms of the accurate Kohn-Sham solutions, the approximate exchange functionals are found to be responsible for the errors of GGA-type methods, which characteristically overestimate the exchange in A(2)(+). These so-called exchange functionals implicitly use localized holes. Such localized holes do occur if there is left-right correlation, i.e., the exchange functionals then also describe nondynamical correlation. However, in the hemibonded A(2)(+) systems the typical molecular (left-right, nondynamical) correlation of the two-electron pair bond is absent. The nondynamical correlation built into the exchange functionals is then spurious and yields too low energies.

Dynamics of the entanglement spectrum in spin chains

We study the dynamics of the entanglement spectrum, that is the time evolution of the eigenvalues of the reduced density matrices after a bipartition of a one-dimensional spin chain. Starting from the ground state of an initial Hamiltonian, the state of the system is evolved in time with a new Hamiltonian. We consider both instantaneous and quasi adiabatic quenches of the system Hamiltonian across a quantum phase transition. We analyse the Ising model that can be exactly solved and the XXZ for which we employ the time-dependent density matrix renormalisation group algorithm. Our results show once more a connection between the Schmidt gap, i.e. the difference of the two largest eigenvalues of the reduced density matrix and order parameters, in this case the spontaneous magnetisation.

Fasciola hepatica:the effect of the microtubule inhibitors colchicine and tubulozole-C on the ultrastructure of the adult fluke

The effect of the microtubule inhibitors colchicine (1 x 10(-3) M) and tubulozole-C(1 x 10(-6) M) on the ultrastructure of adult Fasciola hepatica has been determined in vitro by transmission electron microscopy (TEM), using both intact flukes and tissue-slice material. With colchicine treatment, the apical membrane of the tegument became increasingly convoluted and blebbed, while accumulations of T1 secretory bodies occurred in the basal region of the syncytium, leading to progressively fewer secretory bodies in the syncytium. In the tegumental cells there were distinct accumulations of T1 secretory bodies around the Golgi complexes, which remained active for up to 12 h incubation. Tubulozole-treated flukes showed more severe effects, with initial accumulations of secretory bodies, both at the tegumental apex and base. This was followed in the later time-periods by the sloughing of the tegumental syncytium. In the underlying tegumental cells, the granular endoplasmic reticulum (GER) cisternae were swollen and disrupted, becoming concentrated around the nucleus. The Golgi complexes were dispersed to the periphery of the cells and gradually disappeared from the cytoplasm. After treatment with both drugs, the cell population in the vitelline follicles was altered, with an abnormally large proportion of stem cells and relatively few intermediate type 1 cells. The nurse cell cytoplasm became fragmented and was no longer in contact with the vitelline cells, while the shell globule clusters within the intermediate type 2 and mature cells were loosely packed. In the mature vitelline cells, 'yolk' globules and glycogen deposits became fewer than normal and lipid droplets were observed. The results are discussed in relation to the different modes of action of the two drugs and potential significance of this to anthelmintic (benzimidazole) therapy.

I/Q imbalance in two-way AF relaying: Power allocation and performance analysis

We investigate the performance of dual-hop two-way amplify-and-forward (AF) relaying in the presence of inphase and quadrature-phase imbalance (IQI) at the relay node. In particular, the effective signal-to-interference-plus-noise ratio (SINR) at both sources is derived. These SINRs are used to design an instantaneous power allocation scheme, which maximizes the minimum SINR of the two sources under a total transmit power constraint. The solution to this optimization problem is analytically determined and used to evaluate the outage probability (OP) of the considered two-way AF relaying system. Both analytical and numerical results show that IQI can create fundamental performance limits on two-way relaying, which cannot be avoided by simply improving the channel conditions.