Rayleigh–Bénard (RB) convection with free-slip plates and horizontally periodic boundary conditions is investigated using direct numerical simulations. Two configurations are considered, one is two-dimensional (2-D) RB convection and the other one three-dimensional (3-D) RB convection with a rotating axis parallel to the plate, which for strong rotation mimics 2-D RB convection. For the 2-D simulations, we explore the parameter range of Rayleigh numbers $Ra$ from $10^{7}$ to $10^{9}$ and Prandtl numbers $Pr$ from $1$ to $100$. The effect of the width-to-height aspect ratio $\varGamma$ is investigated for $1\leqslant \varGamma \leqslant 128$. We show that zonal flow, which was observed, for example, by Goluskin et al. (J. Fluid. Mech., vol. 759, 2014, pp. 360–385) for $\varGamma =2$, is only stable when $\varGamma$ is smaller than a critical value, which depends on $Ra$ and $Pr$. The regime in which only zonal flow can exist is called the first regime in this study. With increasing $\varGamma$, we find a second regime in which both zonal flow and different convection roll states can be statistically stable. For even larger $\varGamma$, in a third regime, only convection roll states are statistically stable and zonal flow is not sustained. How many convection rolls form (or in other words, what the mean aspect ratio of an individual roll is), depends on the initial conditions and on $Ra$ and $Pr$. For instance, for $Ra=10^{8}$ and $Pr=10$, the aspect ratio $\varGamma _r$ of an individual, statistically stable convection roll can vary in a large range between $16/11$ and $64$. A convection roll with a large aspect ratio of $\varGamma _r = 64$, or more generally already with $\varGamma _r \gg 10$, can be seen as ‘localized’ zonal flow, and indeed carries over various properties of the global zonal flow. For the 3-D simulations, we fix $Ra=10^{7}$ and $Pr=0.71$, and compare the flow for $\varGamma =8$ and $\varGamma = 16$. We first show that with increasing rotation rate both the flow structures and global quantities like the Nusselt number $Nu$ and the Reynolds number $Re$ increasingly behave like in the 2-D case. We then demonstrate that with increasing aspect ratio $\varGamma$, zonal flow, which was observed for small $\varGamma =2{\rm \pi}$ by von Hardenberg et al. (Phys. Rev. Lett., vol. 15, 2015, 134501), completely disappears for $\varGamma =16$. For such large $\varGamma$, only convection roll states are statistically stable. In-between, here for medium aspect ratio $\varGamma = 8$, the convection roll state and the zonal flow state are both statistically stable. What state is taken depends on the initial conditions, similarly as we found for the 2-D case.

We perform a numerical study of the heat transfer and flow structure of Rayleigh–Bénard (RB) convection in (in most cases regular) porous media, which are comprised of circular, solid obstacles located on a square lattice. This study is focused on the role of porosity $\unicode[STIX]{x1D719}$ in the flow properties during the transition process from the traditional RB convection with $\unicode[STIX]{x1D719}=1$ (so no obstacles included) to Darcy-type porous-media convection with $\unicode[STIX]{x1D719}$ approaching 0. Simulations are carried out in a cell with unity aspect ratio, for Rayleigh number $Ra$ from $10^{5}$ to $10^{10}$ and varying porosities $\unicode[STIX]{x1D719}$, at a fixed Prandtl number $Pr=4.3$, and we restrict ourselves to the two-dimensional case. For fixed $Ra$, the Nusselt number $Nu$ is found to vary non-monotonically as a function of $\unicode[STIX]{x1D719}$; namely, with decreasing $\unicode[STIX]{x1D719}$, it first increases, before it decreases for $\unicode[STIX]{x1D719}$ approaching 0. The non-monotonic behaviour of $Nu(\unicode[STIX]{x1D719})$ originates from two competing effects of the porous structure on the heat transfer. On the one hand, the flow coherence is enhanced in the porous media, which is beneficial for the heat transfer. On the other hand, the convection is slowed down by the enhanced resistance due to the porous structure, leading to heat transfer reduction. For fixed $\unicode[STIX]{x1D719}$, depending on $Ra$, two different heat transfer regimes are identified, with different effective power-law behaviours of $Nu$ versus $Ra$, namely a steep one for low $Ra$ when viscosity dominates, and the standard classical one for large $Ra$. The scaling crossover occurs when the thermal boundary layer thickness and the pore scale are comparable. The influences of the porous structure on the temperature and velocity fluctuations, convective heat flux and energy dissipation rates are analysed, further demonstrating the competing effects of the porous structure to enhance or reduce the heat transfer.

The People's Action Party (PAP) of Singapore is one of the world's longest ruling dominant parties, having won every general election since the country's independence in 1965. Why do Singaporeans consistently vote for the PAP, contrary to the expectations of democratization theories? We argue that valence considerations—specifically, perceptions of party credibility—are the main factor in the voting behavior of Singapore's electorate, and are critical to explaining the PAP's resilience. Furthermore, we argue that the primacy of valence politics arose in part by design, as the PAP has used its control of Singapore's high-capacity state to reshape society and thereby reshape voter preferences towards its comparative advantages. We use a multi-methods approach to substantiate this argument, including a comprehensive quantitative analysis of recent elections. Ultimately, our findings suggest that a focus on valence politics can increase the resilience of dominant parties, but that such a strategy also faces natural limits.

Field studies were conducted in Arizona and California to evaluate the performance of glyphosate-tolerant lettuce and to determine the critical time of weed removal. Glyphosate was applied as a single or as a sequential application at 840 g ae/ha. Single glyphosate applications were made to lettuce at the two-, four-, six-, and eight-leaf stages. Sequential applications were made to lettuce at the two- or four-leaf stage followed by (fb) a second application 14 d after the first. Weed control efficacy, weeding times, and lettuce yield were all measured. Overall, glyphosate applied postemergence (POST) provided better weed control than the commercial standards bensulide or pronamide applied preemergence. Single glyphosate applications at the four-leaf stage and sequential applications at the two-leaf stage fb a second application 14 d later provided excellent control of most weeds, including redroot pigweed. Estimates of the critical time of weed removal were 26 to 29 d after emergence. Glyphosate treatments caused no adverse effects on lettuce. Lettuce head fresh weights in the glyphosate treatments were equal to or higher than those in bensulide or pronamide treatments. For crops such as lettuce, with few effective herbicides, the development of glyphosate-tolerant lettuce offers the opportunity to develop effective POST weed control programs.

For exploring the prospect of higher-k dielectric phase engineering on a high mobility substrate, films of Hf1-xZrxO2 with varying x-values (0 ≤ x ≤ 1) were deposited on Al2O3 passivated Ge substrates using atomic layer deposition (ALD) with a cyclic deposit-anneal-deposit-anneal (DADA) scheme. The evolution of monoclinic to higher-k tetragonal structure with increasing ZrO2 concentration was probed by grazing incident x-ray diffraction and partial reciprocal space maps using the highly brilliant synchrotron x-ray source at the Cornell High Energy Synchrotron Source (CHESS). A primarily amorphous/nano-crystalline matrix of the asdeposited films changed to randomly aligned grains of nanocrystalline MO2 (M=Hf, Zr) after post deposition annealing at 800 °C for 200 seconds. In contrast, the DADA films annealed for same thermal budget showed high degree of preferred orientation along certain crystallographic directions. With increasing ZrO2 content, the structure of the films changed from a monoclinic to a tetragonal phase. A lower amount of ZrO2 (x = 0.33) was required for stabilizing the tetragonal phase in films grown on Al2O3 passivated Ge substrate as compared to similar films grown on a Si substrate via the same DADA process (x ≥ 0.50).

It has been postulated that aging is the consequence of an accelerated accumulation of somatic DNA mutations and that subsequent errors in the primary structure of proteins ultimately reach levels sufficient to affect organismal functions. The technical limitations of detecting somatic changes and the lack of insight about the minimum level of erroneous proteins to cause an error catastrophe hampered any firm conclusions on these theories. In this study, we sequenced the whole genome of DNA in whole blood of two pairs of monozygotic (MZ) twins, 40 and 100 years old, by two independent next-generation sequencing (NGS) platforms (Illumina and Complete Genomics). Potentially discordant single-base substitutions supported by both platforms were validated extensively by Sanger, Roche 454, and Ion Torrent sequencing. We demonstrate that the genomes of the two twin pairs are germ-line identical between co-twins, and that the genomes of the 100-year-old MZ twins are discerned by eight confirmed somatic single-base substitutions, five of which are within introns. Putative somatic variation between the 40-year-old twins was not confirmed in the validation phase. We conclude from this systematic effort that by using two independent NGS platforms, somatic single nucleotide substitutions can be detected, and that a century of life did not result in a large number of detectable somatic mutations in blood. The low number of somatic variants observed by using two NGS platforms might provide a framework for detecting disease-related somatic variants in phenotypically discordant MZ twins.

Abstract. The gay, lesbian, bisexual and transgendered (GLBT) population is a good example of a demographic group that has been understudied because it is difficult to develop a subsample of sufficient size from typical national samples. Here we exploit the extraordinary size of a 2006 online election day survey (with about 35,000 respondents) to examine how the GLBT community behaves politically. While it will surprise no one that this community bestowed little support on Stephen Harper's Conservative party in the 2006 federal election, the factors behind such a consistent vote pattern are not adequately understood. In order to shed more light on the voting behaviour of the GLBT electorate, we develop a socio-demographic profile of the group, and explore three explanatory angles: 1) salience of issue campaign dynamics, given that the same-sex marriage issue was prominent in 2006; 2) ideological and attitudinal proclivities; and 3) strategic considerations.

Résumé. La population gaie, lesbiennes, bisexuels et transgenres (GLBT) est un exemple d'un groupe démographique qui a été peu étudié, car il est difficile de développer un sous-échantillon de taille suffisante à partir d'échantillons nationaux. Ici, nous exploitons la taille extraordinaire d'une enquête enligne du jour du scrutin fédérale du 2006 (avec environ 35.000 répondants) d'examiner comment la communauté GLBT se comporte politiquement. Bien qu'il ne surprendra personne que cette communauté accordé peu d'appui sur Parti conservateur de Stephen Harper lors de l'élection fédérale de 2006, les facteurs qui expliquent un tel motif ne sont pas bien compris. Afin de jeter plus de lumière sur le comportement de vote de l'électorat GLBT, nous développons un profil sociodémographique de cette groupe, et d'explorer trois angles explicatives: 1) pertinence de la question du mariage de même sexe, 2) tendances idéologiques, et 3) des considérations stratégiques.

Abstract. An invariant feature of constituency election campaigns is the literature mail drop, usually a one-page leaflet or card left at the door profiling the candidate and appealing for electoral support. In this article, we report on a field experiment designed to assess the effects of such mail drops. The experiment was conducted during the 2007 Ontario provincial election campaign in the constituency of Cambridge and entailed distributing literature for the Green party candidate in that constituency. After randomly assigning constituency polls to treatment and control groups, and delivering the Green candidate's partisan literature only to the selected treatment group polls, we compared the candidate's support levels in the treated polls with those in the control group. Our research detected a modest effect associated with the literature drop. The effect was largely limited to constituency neighbourhoods fitting at least part of the Green party's traditional demographic, that is, those with higher than average socio-economic status.

Résumé. Un trait commun des campagnes électorales au niveau des circonscriptions est la distribution de publipostages. Il s'agit habituellement d'un dépliant d'une page déposé dans la boîte aux lettres et donnant le profil du candidat tout en invitant les gens à voter pour lui. Notre article porte sur une expérience que nous avons menée pour évaluer les effets de ces publipostages sur le vote. Au cours de la campagne des élections provinciales de l'Ontario, en 2007, dans la circonscription de Cambridge. nous avons distribué des documents sur le candidat du Parti vert de cette circonscription. Les bureaux de scrutin ont étés divisés, au hasard, en deux groupes, soit un groupe de traitement et un groupe de contrôle. Nous avons distribué les documents seulement aux électeurs du premier groupe. Après l'élection, nous avons comparé les niveaux d'appui au candidat vert dans les deux groupes. Les résultats montrent un effet modeste associé à la distribution des publipostages. L'effet observé était en grande partie limité aux quartiers répondant, en partie du moins, au profil démographique traditionnellement favorable aux partis écologiques, soit les quartiers ayant un statut socio-économique plus élevé que la moyenne.

We report on findings from alternative ways of assessing the meaning given to “left” and “right” by respondents in the 1984 National Election Study. Approximately 40 per cent of the sample supplied definitions of the concepts; in comparison, about 60 per cent stated their feelings toward left-wingers and right-wingers and described their political orientations using a seven-point left/right rating scale. Left signified socialism or communism for about one-half of those who supplied definitions, and dislike for left-wingers seemed to be associated with these conceptions of left. Right, which was much more highly regarded than left, signified conservatism for one-quarter of those who defined the term. We also factor analyzed respondents' self-ratings on the left/right scale along with their answers to 15 attitude statements. Left was weakly associated with support for labour's use of the strike weapon. In a criterion group of respondents who had completed university and who had ventured definitions of left and right, self-ratings correlated with factors tapping attitudes toward the military and toward economic disparity and social welfare. As expected, respondents' ratings of themselves on the left/right scale were more similar to their ratings of their preferred parties than to their ratings of other parties. The relationship between self-ratings and ratings of preferred parties generally varied directly with the strength of party identification. We conclude with some observations about the political utility of political labels such as left and right.

The study explored the sources of political knowledge using data from the 1984 Canadian National Election Study. Two dimensions of political knowledge were measured: factual knowledge, in which respondents were asked to name the 10 provincial premiers; and conceptual knowledge, in terms of respondents’ abilities to define and use the concepts of left and right. The authors tested four explanations of people's levels of political knowledge; these dealt with education, political participation, media effects and region, with controls for income, residency in several provinces, age and sex. Education was significantly associated with both forms of knowledge, but especially with conceptual knowledge. Reading about politics in newspapers and magazines was strongly related to the two knowledge variables. The effects of reliance on television for political information, however, were much weaker. There were significant effects for region, with the patterns depending on the type of knowledge. The study concludes with some observations about the role of knowledge in political behaviour.

The authors tested predictions concerning the effects of respondents' identification with governing versus opposition political parties on feelings of political efficacy and trust, using data from the 1984 Canadian National Election Study. Dependent variables were political competence, perceived system responsiveness, and political trust, each measured federally and provincially. Respondents who supported the party in power scored significantly higher on perceived responsiveness and trust than those who supported opposition parties, although mainly at the provincial level. Whether respondents' preferred party was in power or not interacted with strength of party identification on the responsiveness and trust measures, both federally and provincially, as expected. Effects were much less pronounced for feelings of political competence. The authors suggest an interpretation to explain the weaker and inconsistent federal results. The article concludes with some observations concerning the relationship between partisanship, on the one hand, and efficacy and trust, on the other.