1,905 research outputs found

    Plateau Inflation from Random Non-Minimal Coupling

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    A generic non-minimal coupling can push any higher-order terms of the scalar potential sufficiently far out in field space to yield observationally viable plateau inflation. We provide analytic and numerical evidence that this generically happens for a non-minimal coupling strength ξ\xi of the order Ne2N_e^2. In this regime, the non-minimally coupled field is sub-Planckian during inflation and is thus protected from most higher-order terms. For larger values of ξ\xi, the inflationary predictions converge towards the sweet spot of PLANCK. The latter includes ξ104\xi\simeq 10^4 obtained from CMB normalization arguments, thus providing a natural explanation for the inflationary observables measured.Comment: 9 pages, twocolumn, some figures; v2: 1 figure and appendix added, jcap layou

    N=31 is not IIB

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    We adapt the spinorial geometry method to investigate supergravity backgrounds with near maximal number of supersymmetries. We then apply the formalism to show that the IIB supergravity backgrounds with 31 supersymmetries preserve an additional supersymmetry and so they are maximally supersymmetric. This rules out the existence of IIB supergravity preons.Comment: 7 page

    Pole Inflation - Shift Symmetry and Universal Corrections

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    An appealing explanation for the Planck data is provided by inflationary models with a singular non-canonical kinetic term: a Laurent expansion of the kinetic function translates into a potential with a nearly shift-symmetric plateau in canonical fields. The shift symmetry can be broken at large field values by including higher-order poles, which need to be hierarchically suppressed in order not to spoil the inflationary plateau. The herefrom resulting corrections to the inflationary dynamics and predictions are shown to be universal at lowest order and possibly to induce power loss at large angular scales. At lowest order there are no corrections from a pole of just one order higher and we argue that this phenomenon is related to the well-known extended no-scale structure arising in string theory scenarios. Finally, we outline which other corrections may arise from string loop effects.Comment: twocolumn, 9 pages, 1 figure; v2: clarifications and refs added, JHEP layout, 19 page

    Cross compliance and competitiveness of the European beef and pig sector

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    Beef and pig production are important sectors affected by the cross-compliance policy. Full compliance with SMRs and GAECs generates costs and benefits which may have an impact on the competitiveness of these sectors on the world market. Compliance with the Nitrate Directive, animal identification and registration requirements and animal welfare standards can give rise to non-negligible cost of production increases at individual farm level and at sector level. Additional costs can be relevant either due to a low degree of compliance or by significant adjustments costs at farm level. Full compliance generates a level playing field between Member States of the EU, as some countries have to face higher additional costs than others, which are be attributed to differences in degree of compliance. This paper first presents evidence of additional costs at individual farm level due to full compliance. Then for beef and pork a methodology has been developed in order to calculate sector cost impacts following an upcsaling procedure for each of the analysed directives. Simulations with the GTAP model have enabled an assessment of the trade effect of compliance with standards and the impact on the external competitiveness of the EU beef and pork production. In some policy fields covered by cross-compliance important trade partners such as Canada, USA and New Zealand have implemented policies similar to the EU. In these three countries comparable standards to those in the EU were identified and the level and cost of compliance have been assessed. The pig sector will be affected most by a unilateral compliance with standards in the EU, in particular as the Nitrate Directive is concerned. Within the EU pig production costs will rise by 0.545 %. Imports may increase by 4% and exports may fall by 3%. However full application of the Clean Water Act in the US, which contains similar obligations to the Nitrate Directive, generates a significant sector cost increase (1,08%) which may counterbalance the loss of competitiveness of EU pork production towards the US. Compliance with the mandatory animal welfare standards has only minor cost implications and has negligible effects on external competitiveness of the EU both because of a high degree of compliance and relatively low adjustment costs at farm level. Finally, in many EU member states the degree of compliance of beef farms with the animal registration and identification directives is below 100%. Additional costs for full compliance within the EU have been estimated at 0.455%, which may cause an increase of beef imports of 2.21% and a decline of exports of ¿2.12%. This loss in competitiveness of the EU will further favour the position of Brazil on the world beef market. At the other hand significant benefits are obtained in food security of EU beef

    Strengthening of Parenthood; Developing a Life Skills Questionnaire for Dutch Parents (LSQ-P)

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    AbstractLife skills of parents have a positive effect on the wellbeing of parents and development of children. Currently, no reliable instrument is available to measure these skills. This study was set up to develop a questionnaire for assessing parents’ life skills. The questionnaire was developed for professionals who are working with parents and for building behavioral interventions enhancing the wellbeing of parents. A pilot research using a translation of the Life Skills Scale (Erawan, 2010) was conducted. Construct validity and reliability by means of confirmatory factor analysis of nine scales were examined in a sample of 133 Dutch parents and reliability of the scales in terms of Cronbach's alpha was examined. Evidence for construct validity of the scales was found. Reliability coefficients were satisfactory for the scales Critical thinking, Social responsibility, Interpersonal relationships, Decision making, Self-awareness, and Creative thinking. Reliability coefficients were good for Empathy and Self-esteem. The LSQ-P can be used in social work practice as an assessment tool to measure strengths and weaknesses regarding life skills of parents. More attention for developing life skills of parents is necessary in order to increase their wellbeing. Implications for health promotion among parents are discussed. Suggestions for further research and development of the scales are outlined

    The Classification of Highly Supersymmetric Supergravity Solutions

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    The spinorial geometry method is an effective method for constructing systematic classifications of supersymmetric supergravity solutions. Recent work on analysing highly supersymmetric solutions in type IIB supergravity using this method is reviewed [arXiv:hep-th/0606049, arXiv:0710.1829]. It is shown that all supersymmetric solutions of IIB supergravity with more than 28 Killing spinors are locally maximally supersymmetric.Comment: 23 pages, latex. To appear in the proceedings of the Special Metrics and Supersymmetry conference at Universidad del Pais Vasco, May 2008. References correcte

    Monolith formation and ring-stain suppression in low-pressure evaporation of poly(ethylene oxide) droplets

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    When droplets of dilute suspensions are left to evaporate the final dry residue is typically the familiar coffee-ring stain, with nearly all material deposited at the initial triple line (Deegan et al, Nature, vol. 389, 1997, pp. 827-829). However, aqueous poly(ethylene oxide) (PEO) droplets only form coffee-ring stains for a very narrow range of the experimental parameters molecular weight, concentration and drying rate. Instead, over a wide range of values they form either a flat disk or a very distinctive tall central monolith via a four-stage deposition process which includes a remarkable bootstrap-building step. To predict which deposit will form, we present a quantitative model comparing the effects of advective build-up at the triple line to diffusive flux and use this to calculate a dimensionless number χ. By experimentally varying concentration and flux (using a low-pressure drying chamber), the prediction is tested over nearly two orders of magnitude in both variables and shown to be in good agreement with the boundary between disks and monoliths at χ ≈ 1.6
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