Political debates are structured by underlying conflict dimensions, such as left-right and economic and cultural ideology, which form the basis for voter choice and party competition. However, we know little about how voters arrive at perceptions of parties' positions on these dimensions. We examine how the emphasis parties place on the different issues that make up a higher-level ideological dimension affects perceptions of their position on that dimension. Using two population-based survey experiments, we present respondents with either short or long statements that communicate the same issue stances. We then test whether the length of statements affects positional perceptions on the higher-level dimension. The empirical results show support for our hypotheses and imply that political parties – and the context in which they compete – can affect their perceived position even if underlying issue stances remain stable.

Position change is an essential feature of political competition. Implicitly, policy change on an issue dimension is often equated with opinion change on specific issues within that dimension. However, in addition to opinion-based policy change, we highlight that parties and candidates can change their overall position by increasing their emphasis on certain opinions within that issue dimension (emphasis-based policy change). Using party manifesto data, we find that parties differ in their use of each type of policy change based on aspects of party organization, particularly the relative power of leaders and activists. Leader-dominated parties are more likely to engage in opinion-based policy change, also in reaction to systemic policy shifts. In contrast, activist-dominated parties tend to change their overall position in reaction to systemic shifts by emphasizing certain positions more. Our approach links salience-based to spatial models of party competition and has broader implications for how we study party competition.

Parties and politicians want their messages to generate media coverage and thereby reach voters. This article examines how attributes related to content and sender affect whether party messages are likely to get media attention. Based on content analyses of 1,613 party press releases and 6,512 media reports in a parliamentary, multiparty context, we suggest that party messages are more likely to make it into the news if they address concerns that are already important to the media or other parties. Discussing these issues may particularly help opposition parties and lower-profile politicians get media attention. These results confirm the importance of agenda setting and gatekeeping, shed light on the potential success of party strategies, and have implications for political fairness and representation.

It is easier for voters to make informed electoral choices when parties talk about the same issues. Yet, parties may decide against such “issue engagement.” We hypothesize that issue engagement between parties is more likely (a) when the similarity of their policy positions means that both parties have clear electoral incentives to talk about the same topics and (b) when parties face few organizational constraints in terms of campaign resources. Our empirical analysis of 2453 press releases by Austrian parties shows that ideological proximity and party resources affect the level of issue engagement. These findings suggest that issue engagement is less likely precisely where it is needed most, which has important implications for understanding the democratic quality of election campaigns.

Understanding the interaction of group V impurities with intrinsic defects in ZnO is important for developing p-type material. We have studied N-doped ZnO thin films and N-doped bulk ZnO crystals, with positron annihilation spectroscopy, in contrast to earlier studies that have concentrated on N-implanted ZnO crystals. We show that the introduction of N impurities into ZnO, irrespective of whether it is done during the growth of thin films or bulk crystals or through implantation and subsequent thermal treatments, leads to the formation of stable vacancy clusters and negative ion-type defects. Interestingly, the stability of these vacancy clusters is found almost exclusively for N introduction, whereas single Zn vacancy defects or easily removable vacancy clusters are more typically found for ZnO doped with other impurities.

The Apodizing Phase Plate (APP) coronagraph has been used to image the exoplanet β Pictoris b and the protoplanet candidate around HD 100546, and is currently in use in surveys with NaCo at the VLT. Its success is due to its tolerance to tip-tilt pointing errors in current AO systems, which degrade the performance of nearly all other coronagraphs. Currently the sensitivity of the APP is limited by non-common path errors in the science camera systems and by its chromatic behaviour. We present the achromatized Vector APP coronagraph and address how we will measure and minimise non-common path errors with Focal Plane Wavefront Sensing algorithms.

We investigated the transport systems that can sustain Na+ and Cl- movements across bovine gall bladder epithelium, focusing on the Na+-H+ exchanger (NHE) family and chloride conductive pathways. Experiments conducted using the fluorescent probe acridine orange (AO) with brush-border membrane vesicles (BBMV) or vesicles obtained from the total epithelium (EMV) demonstrated the presence of a Na+-H+ exchange in both preparations. The use of specific inhibitors indicated the presence of an apical NHE3 exchanger and a NHE1 isoform which should reside in the basolateral membrane. Using reverse transcriptase (RT) PCR, we identified cDNA fragments corresponding to the NHE1, NHE3, Cl--HCO3- (AE2a) transporters and to the CFTR channel. Using the patch-clamp technique, we investigated Cl- conductances on cultured epithelial cells. We found a 5 pS Cl- channel with a voltage-independent open probability, insensitive to stilbenes (SITS), Zn2+ and cAMP. The results suggest that absorption and secretion coexist in calf gall bladder epithelium. A Na+-H+-Cl--HCO3- double exchange may, at least partially, sustain the absorptive function, and a Cl- apical conductive pathway may be involved in secretion. The conductance we observed does not seem to be cAMP-regulated, unlike other mammalian gall bladders. Experimental Physiology (2001) 86.5, 571-583.

Members of the Ly-6/uPAR protein family share one or several repeat units of the Ly-6/uPAR domain that is defined by a distinct disulfide bonding pattern between 8 or 10 cysteine residues. The Ly-6/uPAR protein family can be divided into two subfamilies. One comprises GPI-anchored glycoprotein receptors with 10 cysteine residues. The other subfamily includes the secreted single-domain snake and frog cytotoxins, and differs significantly in that its members generally possess only eight cysteines and no GPI-anchoring signal sequence. We report the purification and structural characterization of human SLURP-1 (secreted mammalian Ly-6/uPAR related protein 1) from blood and urine peptide libraries. SLURP-1 is encoded by the ARS (component B)-81/s locus, and appears to be the first mammalian member of the Ly-6/uPAR family lacking a GPI-anchoring signal sequence. A phylogenetic analysis based on the SLURP-1 primary protein structure revealed a closer relationship to the subfamily of cytotoxins. Since the SLURP-1 gene maps to the same chromosomal region as several members of the Ly-6/uPAR subfamily of glycoprotein receptors, it is suggested that both biologically distinct subfamilies might have co-evolved from local chromosomal duplication events.