The nematic phase of a system of long hard rods

We consider a two-dimensional lattice model for liquid crystals consisting of long rods interacting via purely hard core interactions, with two allowed orientations defined by the underlying lattice. We rigorously prove the existence of a nematic phase, i.e., we show that at intermediate densities the system exhibits orientational order, either horizontal or vertical, but no positional order. The proof is based on a two-scales cluster expansion: we first coarse grain the system on a scale comparable with the rods' length; then we express the resulting effective theory as a contour's model, which can be treated by Pirogov-Sinai methods.Comment: 36 pages, 4 figures; abstract changed, references added, comparison with literature improved, figures adde

Plate-nematic phase in three dimensions

We consider a system of anisotropic plates in the three-dimensional continuum, interacting via purely hard core interactions. We assume that the particles have a finite number of allowed orientations. In a suitable range of densities, we prove the existence of a uni-axial nematic phase, characterized by long range orientational order (the minor axes are aligned parallel to each other, while the major axes are not) and no translational order. The proof is based on a coarse graining procedure, which allows us to map the plate model into a contour model, and in a rigorous control of the resulting contour theory, via Pirogov-Sinai methods.Comment: 29 pages, 4 figure

cpDNA barcoding by combined End-Point and Real-Time PCR analyses to identify and quantify the main contaminants of oregano (Origanum vulgare L.) in commercial batches

Oregano (Origanum vulgare L.) is a flowering plant that belongs to the mint family (Lamiaceae). It is used as a culinary herb and is often commercialized as a fine powder or a mixture of small fragments of dried leaves, which makes morphological recognition difficult. Like other commercial preparations of drugs and spices, the contamination of oregano mixtures with vegetable matter of lower quality, or the use of generic misleading names, are frequent and stress the need to develop a molecular traceability system to easily, quickly, and cheaply unveil these scams. The DNA-based analytical approach known as cpDNA barcoding is particularly suited for fraud identification in crop plant species (fresh products and food derivatives), and it represents a promising traceability tool as an alternative or complement to traditional detection methods. In the present study, we used a combined approach based on both qualitative and quantitative cpDNA barcoding with end-point and real-time polymerase chain reaction (PCR) analyses to assess the type and degree of contamination in commercial batches of common oregano. In a preliminary qualitative screening, we amplified, cloned, and sequenced a number of universal trnH-psbA- and trnL-barcoded regions, to identify the main contaminants in the samples under investigation. On the basis of these findings, we then developed and validated a species-specific and sequence-targeted method of testing for the quantitative assessment of contaminants, using trnL gene intron assays. Surprisingly, the results obtained in our case study indicated an almost total absence of O. vulgare in the commercial batches analyzed, but a high presence of group I contaminants (Satureja pilosa Velen.), and a moderate presence of group II contaminants (Cistus lanidifer L./Cistus albidus)

An exploration of the differential effects of parents\u2019 authoritarianism dimensions on pre-school children\u2019s epistemic, existential, and relational needs.

Research on adult populations has widely investigated the deep differences that characterize individuals who embrace either conservative or liberal views of the world. More recently, research has started to investigate these differences at very early stages of life. One major goal is to explore how parental political ideology may influence children's characteristics that are known to be associated to different ideological positions. In the present work, we further investigate the relations between parents' ideology and children cognitive processing strategies within the framework of political ideology as motivated social cognition (Jost et al., 2003) and the dual process model of political ideology (Duckitt et al., 2002). Specifically, epistemic (implicit attitudes toward order vs. chaos), existential (negativity and threat bias), and relational needs (conformity measure) were assessed in pre-school children (N = 106; 4-6 years). For each child at least one parent completed both the Social Dominance Orientation (SDO) and the Right Wing Authoritarianism (RWA) measures. Interestingly, results indicated that mothers' and fathers' responses had unique associations with children's socio-cognitive motivations, and different findings emerged in relation to the two facets of parental authoritarianism, namely dominance (i.e., SDO) and submission (i.e., RWA). More specifically, children's existential needs appeared to be more related to mothers' RWA scores, whereas children's epistemic needs appeared to be more related to fathers' SDO. Finally, parents' RWA and SDO scores appeared to have opposite effects on children's relational needs: children's conformity increased at increasing levels of mothers' RWA and decreased at increasing levels of fathers' SDO. Overall, however, results were relatively weak and several links between the responses of parents and their children were not significant, suggesting caution in drawing strong conclusions about the impact of parents' ideology. Limitations and future developments will be discussed

Preference erosion and the developing countries exports to the EU: a dynamic panel gravity approach

Since 2004 there has been a sharp decrease in border protection for the EU rice industry. Because the EU grants trade preferences to a considerable number of rice exporting developing countries, the reform implied preference erosion as well. By addressing the impact of preference erosion on developing countries rice exports to the EU, this paper contributes two original insights to the literature: first, by proposing a new empirical approach to compute the preference margin when tariff rate quotas are in force which is based on the assumption of the existence of fixed costs and economies of scale in international trade; second, by estimating the trade elasticities of preferences by means of a dynamic panel gravity equation to deal with the issues of endogeneity of preferences and persistency in bilateral trade flows. The results show that the way preference margins are calculated matters significantly when assessing the existence and extent of their erosion and the values of trade elasticities. Finally, the estimations highlight the fact that the impact of preferences is still very strong for some of the countries concerned.Trade Preferences, Gravity Equation, Tariff Rate Quotas, EU Rice Policy, GMM, Agricultural and Food Policy, International Relations/Trade, F13, Q17, F14,

Exploiting supplier capabilities to maximise product design opportunities in the fuzzy front end activities

This paper explores the Fuzzy Front-End (FFE), i.e. the first phase of the Product Design and Development process where a company formulates a product concept to be developed and decides whether or not to invest resources in the further development of an idea. Our goal is to understand how companies leverage supply chain capabilities to improve product design opportunities in order to obtain optimized product concepts in the FFE. From the analysis of our pilot study, the results suggest that FFE is organized differently depending on design requirements and supply chain capabilities and that matching design requirements with supplier capabilities during the FFE improves performance. Therefore, the findings indicate that the proposed Conceptual Framework has the potential to be used by companies to design their FFE and to enhance the use of supply chain capabilities in their product design activities

Conditional Correlations in the Returns on Oil Companies Stock Prices and Their Determinants

The identification of the forces that drive stock returns and the dynamics of their associated volatilities is a major concern in empirical economics and finance. This analysis is particularly relevant for determining optimal hedging strategies based on whether shocks to the volatilities of returns of oil companies stock prices, relevant stock market indexes and oil spot and futures prices are high or low, and positively or negatively correlated. This paper investigates the correlations of volatilities in the stock price returns and their determinants for the most important integrated oil companies, namely Bp (BP), Chevron-Texaco (CVX), Eni (ENI), Exxon-Mobil (XOM), Royal Dutch (RD) and Total-Fina Elf (TFE). We measure the actual co-risk in stock returns and their determinants “within” and “between” the different oil companies, using multivariate cointegration techniques in modelling the conditional mean, as well as multivariate GARCH models for the conditional variances. We focus first on the determinants of the market value of each company using the cointegrated VAR/VECM methodology. Then we specifiy the conditional variances of VECM residuals with the Constant Conditional Correlation (CCC) multivariate GARCH model of Bollerslev (1990) and the Dynamic Conditional Correlation (DCC) multivariate GARCH model of Engle (2002). The “within” and “between” DCC indicate low to high/extreme interdependence between the volatilities of companies’ stock returns and the relevant stock market indexes or Brent oil prices.Constant conditional correlations, Dynamic conditional correlations, Multivariate GARCH models, Stock price indexes, Brent oil prices, Spot and futures prices, Multivariate cointegration, VECM

Too Different To Get Along: Inequality and Global Public Goods

We study how inequality affects the feasibility of an international agreement on the provision of an environmental public good in a two-country two-level political economy model. At the international level, two negotiators try to agree on the respective country's provision of the public good under different international equity rules, knowing that this agreement will need to be accepted by the median voter in each country. At the national level, agents' preferences for the public good depend on their relative income position, which implies that negotiators must also take into account the level of inequality within their country. We show that the feasibility of the agreement and the distribution of the gains from cooperation depends on the equity rule imposed, on the levels of within-country inequality, and on the level of cross-country inequality

Business continuity in the COVID-19 emergency: A framework of actions undertaken by world-leading companies

none2openMargherita A; Heikkilä MMargherita, A; Heikkilä,