2,874 research outputs found

    Multiple Scales in Pati-Salam Unification Models

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    We investigate models where gauge unification (GUT) proceeds in steps that include Pati-Salam symmetry. Beyond the Standard Model, we allow for a well-defined set of small representations of the GUT gauge group. We show that all possible chains of Pati-Salam symmetry breaking can be realized in accordance with gauge-coupling unification. We identify, in particular, models with unification near the Planck scale, with intermediate left-right or SU(4) quark-lepton symmetries that are relevant for flavor physics, with new colored particles at accessible energies, and with an enlarged electroweak Higgs sector. We look both at supersymmetric and non-supersymmetric scenarios.Comment: 48 pages, 11 figures, version accepted for publication in JHE

    Combining Pati-Salam and Flavour Symmetries

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    We construct an extension of the Standard Model (SM) which is based on grand unification with Pati-Salam symmetry. The setup is supplemented with the idea of spontaneous flavour symmetry breaking which is mediated through flavon fields with renormalizable couplings to new heavy fermions. While we argue that the new gauge bosons in this approach can be sufficiently heavy to be irrelevant at low energies, the fermionic partners of the SM quarks, in particular those for the third generation, can be relatively light and provide new sources of flavour violation. The size of the effects is constrained by the observed values of the SM Yukawa matrices, but in a way that is different from the standard minimal-flavour violation approach. We determine characteristic deviations from the SM that could eventually be observed in future precision measurements.Comment: 26 pages, 5 figure

    A comparison between obstructions to local-global principles over semiglobal fields

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    We consider local-global principles for rational points on varieties, in particular torsors, over one-variable function fields over complete discretely valued fields. There are several notions of such principles, arising either from the valuation theory of the function field, or from the geometry of a regular model of the function field. Our results compare the corresponding obstructions, proving in particular that a local-global principle with respect to valuations implies a local-global principle with respect to a sufficiently fine regular model.Comment: 10 pages; published versio

    Numerical simulation of the deformation behavior of softwood tracheids for the calculation of the mechanical properties of wood-polymer composites

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    From a fiber composite point of view, an elongated softwood particle is a composite consisting of several thousand tracheids, which can be described as fiber wound hollow profiles. By knowing their deformation behavior, the deformation behavior of the wood particle can be described. Therefore, a numerical approach for RVE- and FEM-based modelling of the radial and tangential compression behavior of pine wood tracheids under room climate environment is presented and validated with optical and laser-optical image analysis as well as tensile and compression tests on pine sapwood veneer strips. According to the findings, at 23 °C and 12% moisture content, at least 10 MPa must be applied for maximum compaction of the earlywood tracheids. The latewood tracheids can withstand at least 100 MPa compression pressure and would deform elastically at this load by about 20%. The developed model can be adapted for other wood species and climatic conditions by adjusting the mechanical properties of the base materials of the cell wall single layers (cellulose, hemicellulose, lignin), the dimensions and the structure of the vessel elements, respectively

    Big Five personality trait differences between students from different majors aspiring to the teaching profession

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    Person-Environment fit theories claim that students choose their academic path according to their personality. In this regard, teacher candidates are of special interest. On the one hand, they all make the same choice to enroll in a teacher education program. On the other hand, they make different choices with respect to the subjects they are going to teach. If the Person-Environment fit approach also applies to the selection regarding teacher candidates’ subject areas, teacher candidates from different majors might have different personality traits and as a result, different starting conditions for becoming a successful teacher. Such differences need to be taken into account by teacher education in order to create programs that allow teacher candidates from different majors to equally succeed. Therefore, the current study investigates to what extent personality group differences across majors occur within the population of teacher candidates. Using data from a large-scale study, the Big Five personality traits of 1735 female and 565 male teacher candidates were analyzed, with teacher candidates compared to male (n = 1122) and female (n = 1570) students who studied the same major but who did not intend to become teachers. Unlike previous studies, academic majors were not grouped into few broad categories, but eight different majors were distinguished. The results indicate that teacher candidates are more extraverted than their non-teaching counterparts. In addition, personality trait differences between teacher candidates from different majors could be observed. The results are discussed as they relate to the recruitment and training of future teachers

    Acoustical and optical determination of mechanical properties of inorganically-bound foundry core materials

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    Inorganically-bound sand cores are used in many light-metal foundries to form cavities in the cast part, which cannot be realised by the mould itself. To enable FEM simulations with core materials, their mechanical properties have to be measured. In this article, we adapt methods to determine the Young’s and shear modulus, the Poisson ratio and the fracture strain of sand cores. This allows us to fully parametrise an ideal brittle FEM model. We found that the Young’s and shear modulus can be obtained acoustically via the impulse excitation technique. The fracture strain was measured with a high-speed camera and a digital image correlation algorithm

    Determinants of Web-based CSR Disclosure in the Food Industry

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    Purpose –Web-based CSR disclosure provides a variety of advantages for firms. Determining factors for web-based CSR disclosure have been analyzed in several papers. However, only limited research has been conducted on both, the food industry and small and midsized enterprises. This paper is one contribution to fill this gap as we investigate web-based CSR communication of food processors including SME.Design/methodology/approach – We analyzed corporate communication on the websites of 71 food producers from North Rhine-Westphalia, Germany using dictionary-based content analysis. Based on an ordered logit model the relationship between CSR communication and size, profitability, indebtedness and closeness to market was estimated. Economic data were obtained from the commercial database DAFNE.Findings – Our results reveal that larger firms provide relatively more CSR information than smaller firms. There was no significant relationship between CSR disclosure and profitability or indebtedness of a company and an ambiguous relationship with regard to the determinant ‘closeness to market’. Regarding the different areas of communication we found that social compared to environmental aspects were underrepresented.Practical implications – Social aspects of CSR could be used for differentiation in the market. Furthermore, as smaller firms provide relatively less information on CSR it might be worthwhile to analyze the central impediments for CSR communication for those companies.Originality/Value – This paper contributes to the ongoing discussion about firms’ CSR communication. From a convenience sample of 71 food processing firms, including SME, it provides insight regarding the determinants for CSR disclosure on firms’ websites. With the focus on the food industry and the inclusion of SME we contribute with our study to two under-researched areas

    Ultrasonographic assessment of the caudal vena cava diameter in cats during blood donation

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    Objectives: Ultrasonography of the caudal vena cava (CVC) has been previously established to assess fluid status in dogs but not in cats. The aim of this study was to determine CVC diameter changes during feline blood donation. Methods: Inter- and intra-observer variability were assessed in 11 client-owned cats. Minimal and maximal CVC diameters were assessed longitudinally in the subxiphoid view (SV) and right paralumbar view (PV), and transversely in the right hepatic intercostal view (HV). Eighteen client-owned, healthy, anaesthetised cats were evaluated during 21 blood donation procedures of 10 ml/kg in the same anatomical locations before (T0) and after (T1) blood donation, and after volume resuscitation with 30 ml/kg lactated Ringer’s solution (T2). The CVC index was calculated. Results: Intra-observer variability was acceptable for all probe positions, except for the HV, whereas inter-observer variability was considered unacceptable for all probe positions. Complete measurements were obtained during 21 blood donations at T0, T1 and T2 at the SV, during 18/21 blood donations at the HV and during 16/21 blood donations at the PV. At the SV, the minimal CVC diameter between T1 and T2 (P <0.001), and the maximal CVC diameter between T0 and T1 and between T1 and T2 (P <0.001) were significantly different. At the HV, the minimal vertical diameter, maximal vertical diameter and minimal horizontal diameter were different between all timepoints (P <0.001). The maximal horizontal diameter was different between T1 and T2 (P = 0.002). At the PV, both diameters were different between all timepoints (P <0.001). The CVC index was not different between timepoints. Conclusion and relevance: Significant probe position dependent CVC diameter changes with marked overlap were observed before and after blood donation, and after fluid bolus. No absolute CVC diameter could be used to indicate hypovolaemia. Ultrasonographic assessment of the feline CVC is highly operator-dependent. The CVC index is not useful in cats

    Determinants of Web-based CSR Disclosure in the Food Industry

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    Purpose –Web-based CSR disclosure bears a variety of advantages for firms. Determining factors for web-based CSR disclosure have been analyzed in several papers. However, only limited research has been conducted on both, the food industry and small and midsized enterprises. This paper is one contribution to fill this gap as we investigate web-based CSR communication of food processors including SME.Design/methodology/approach – We analyzed corporate communication on the websites of N=71 food producers from North Rhine-Westphalia, Germany using dictionary-based content analysis. Based on an ordered logit model the relationship between CSR communication and size, profitability, indebtedness and closeness to market was estimated. Economic data were obtained from the commercial database Dafne.Findings – Our results reveal that larger firms provide relatively more CSR information than smaller firms. There was no significant relationship between CSR disclosure and profitability or indebtedness of a company and ambiguous ones with regard to the determinant ‘closeness to market’. Regarding the different areas of communication we found that social compared to environmental aspects were underrepresented.Practical implications – Social aspects of CSR could be used for differentiation at the market. Furthermore as smaller firms provide relatively fewer information on CSR it might be worthwhile to analyze central impediments for CSR communication for those companies.Originality/Value – This paper contributes to the ongoing discussion about firms’ CSR communication. It provides for a convenience sample of 71 food processing firms’, including SME, insight regarding the determinants for CSR disclosure on firms’ websites. With the focus on the food industry and the inclusion of SMEs we contribute with our study to two under-researched areas
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