117 resultados para CEF
Resumo:
This dissertation examines the compliance and performance of a large sample of faith based (religious) ethical funds - the Shari'ah-compliant equity funds (SEFs), which may be viewed as a form of ethical investing. SEFs screen their investment for compliance with Islamic law, where riba (conventional interest expense), maysir (gambling), gharar (excessive uncertainty), and non-halal (non-ethical) products are prohibited. Using a set of stringent Shari'ah screens similar to those of MSCI Islamic, we first examine the extent to which SEFs comply with the Shari'ah law. Results show that only about 27% of the equities held by SEFs are Shari'ah-compliant. While most of the fund holdings pass the business screens, only about 42% pass the total debt to total assets ratio screen. This finding suggests that, in order to overcome a significant reduction in the investment opportunity, Shari'ah principles are compromised, with SEFs adopting lax screening rules so as to achieve a financial performance. While younger funds and funds that charge higher fees and are domiciled in more Muslim countries are more Shari'ah-compliant, we find little evidence of a positive relationship between fund disclosure of the Shari'ah compliance framework and Shari'ah-compliance. Clearly, Shari'ah compliance remains a major challenge for fund managers and SEF investors should be aware of Shari'ah-compliance risk since the fund managers do not always fulfill their fiduciary obligation, as promised in their prospectus. Employing a matched firm approach for a survivorship free sample of 387 SEFs, we then examine an issue that has been heavily debated in the literature: Does ethical screening reduce investment performance? Results show that it does but only by an average of 0.04% per month if benchmarked against matched conventional funds - this is a relatively small price to pay for religious faith. Cross-sectional regressions show an inverse relationship between Shari'ah compliance and fund performance: every one percentage increase in total compliance decreases fund performance by 0.01% per month. However, compliance fails to explain differences in the performance between SEFs and matched funds. Although SEFs do not generally perform better during crisis periods, further analysis shows evidence of better performance relative to conventional funds only during the recent Global Financial Crisis; the latter is consistent with popular media claims.
Resumo:
Significant genotypic differences in tolerance of pollen germination and seed set to high temperatures have been shown in sorghum. However, it is unclear whether differences were associated with variation in either the threshold temperature above which reproductive processes are affected, or in the tolerance to increased temperature above that threshold. The objectives of this study were to (a) dissect known differences in heat tolerance for a range of sorghum genotypes into differences in the threshold temperature and tolerance to increased temperatures, (b) determine whether poor seed set under high temperatures can be compensated by increased seed mass, and (c) identify whether genotypic differences in heat tolerance in a controlled environment facility (CEF) can be reproduced in field conditions. Twenty genotypes were grown in a CEF under four day/night temperatures (31.9/21.0 °C, 32.8/21.0 °C, 36.1/21.0 °C, and 38.0/21.0 °C), and a subset of six genotypes was grown in the field under four different temperature regimes around anthesis. The novelty of the findings in this study related to differences in responsiveness to high temperature—genotypic differences in seed set percentage were found for both the threshold temperature and the tolerance to increased maximum temperature above that threshold. Further, the response of seed set to high temperature in the field study was well correlated to that in the CEF (R2 = 0.69), although the slope was significantly less than unity, indicating that heat stress effects may have been diluted under the variable field conditions. Poor seed set was not compensated by increased seed mass in either CEF or field environments. Grain yield was thus closely related to seed set percentage. This result demonstrates the potential for development of a low-cost field screening method to identify high-temperature tolerant varieties that could deliver sustainable yields under future warmer climates.
Resumo:
FePS3 is a layered antiferromagnet (T N=123 K) with a marked Ising anisotropy in magnetic properties. The anisotropy arises from the combined effect of the trigonal distortion from octahedral symmetry and spin-orbit coupling on the orbitally degenerate5 T 2g ground state of the Fe2+ ion. The anisotropic paramagnetic susceptibilities are interpreted in terms of the zero field Hamiltonian, ?=?i [?(L iz 2 ?2)+|?|L i .S i ]?? ij J ij S i .S j . The crystal field trigonal distortion parameter ?, the spin-orbit coupling ? and the isotropic Heisenberg exchange,J ij, were evaluated from an analysis of the high temperature paramagnetic susceptibility data using the Correlated Effective Field (CEF) theory for many-body magnetism developed by Lines. Good agreement with experiment were obtained for ?/k=215.5 K; ?/k=166.5 K;J nn k=27.7 K; andJ nnn k=?2.3 K. Using these values of the crystal field and exchange parameters the CEF predicts aT N=122 K for FePS3, which is remarkably close to the observed value of theT N. The accuracy of the CEF approximation was also ascertained by comparing the calculated susceptibilities in the CEF with the experimental susceptibility for the isotropic Heisenberg layered antiferromagnet MnPS3, for which the high temperature series expansion susceptibility is available.