249 research outputs found

    Is the 52 Week High Strategy as Pervasive as Momentum? Evidence from Arabic Market Indices

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    Existing studies find that momentum can be explained by a strategy based on the 52wk high prices of individual stock and is able to predict returns. This paper uses Arabic market indices data to investigate whether there is momentum and 52wk high strategies and to evaluate the performance of these strategies to achieve the optimal portfolio. We find the 52wk high strategy is unprofitable when applied to Arabic market indices, while the momentum strategy is economically profitable than the 52wk high strategy. The 52wk high effect is not as pervasive and reliable as the momentum effect. After modifying the 52wk high strategy with long-term contrarian using a double sorting procedure, the modified 52wk high strategy has positive profits for all holding periods. However, the momentum strategy is still more profitable than this modified 52wk high strategy. Keywords: Arabic market indices, long-term contrarian, two-factor model.

    Factors Associated with Contraceptive Use among Jordanian Muslim Women: Implications for Health and Social Policy

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    The objectives of this quantitative study were to identify factors associated with contraceptive use by Jordanian Muslim women; to estimate factors that predict the variance in contraceptive use; and recommend appropriate health and social policies to enhance quality of life of Jordanian women. A cross -sectional design was used to collect data from 487 married non-pregnant women aged 18 to 49 years who resided in three southern governorates in Jordan using a structured interview guide. Results showed that 63.2% of women used some form of contraceptive method; IUD was the most frequently used method (44.2%). The percentage of women exposed to violence was 5% and 9.2% for physical and verbal abuse respectively. Findings also showed that there was a significant relationship between psychological wellbeing of women and contraceptive use. Furthermore, no relationship between women’s perceived religious stance towards contraceptives and their use. Predictors of contraceptive use were: women aged 40-45 years explained 23.3% of the variance in contraceptive use; and the woman’s approval of contraceptive use for birth spacing explained 21.4% of the variance in contraceptive use. The Islamic stance towards contraceptive use was not significant in these women; however further studies are needed to confirm these findings as well as the generalizability to Muslim women in other countries. The study findings have implications for health and social policies relevant to family planning services in order to enhance and increase the use of contraceptives to reduce the TFR in Jordan. Furthermore, health care providers, social and economical policy makers need to integrate women’s cultural views and contraceptive use in strategies and policies beyond health to improve women’s quality of life and build on the global consensus for women and children to achieve the Millennium Development goals

    Relationships between herbaceous diversity and biomass in two habitats in arid Mediterranean rangeland

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    Plant diversity patterns vary across the landscape. This study was conducted to answer the question: What is the pattern of species diversity (α and β) along an abstract productivity/cover gradient at two topographical positions (Wadi (a depression with overland flow) and hilltop) of a Mediterranean herbaceous plant community in Jordan? Results indicated that the less productive hilltop localities exhibited higher species richness than the more productive Wadi localities. Species richness exhibited a unimodal relationship with aboveground biomass within Wadis whereas a positive linear relationship was revealed for hilltops. Within Wadis, abundant species did not show a significant relationship with productivity while common and rare species showed a unimodal relationship. Within hilltops, abundant, common, and rare species showed a linear relationship with biomass. β-diversity, measured as species dissimilarity, showed significant negative relationship to biomass within hilltops, whereas a positive relationship was observed within Wadis. Wilson-Shmida index (βT) had a unimodal function with increased differences in productivity whereas Morisita-Horn index (Cmh) showed a reverse unimodal relationship. Examination of the species richness-biomass relationship among species groups (abundant, common, and rare) suggested that abundant species maybe more important on low productivity sites whereas common and rare species maybe more important on high productivity sites

    The development of a radial based integrated network for the modelling of 3D fused deposition

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    Purpose The purpose of this research paper is to investigate and model the fused deposition modelling (FDM) process to predict the mechanical attributes of 3D printed specimens. Design/methodology/approach By exploiting the main effect plots, a Taguchi L18 orthogonal array is used to investigate the effects of such parameters on three mechanical attributes of the 3D printed specimens. A radial-based integrated network is then developed to map the eight FDM parameters to the three mechanical attributes for both PEEK and PEKK. Such an integrated network maps and predicts the mechanical attributes through two consecutive phases that consist of several radial basis functions (RBFs). Findings Validated on a set of further experiments, the integrated network was successful in predicting the mechanical attributes of the 3D printed specimens. It also outperformed the well-known RBF network with an overall improvement of 24% in the coefficient of determination. The integrated network is also further validated by predicting the mechanical attributes of a medical-surgical implant (i.e. the MidFace Rim) as an application. Originality/value The main aim of this paper is to accurately predict the mechanical properties of parts produced using the FDM process. Such an aim requires modelling a highly dimensional space to represent highly nonlinear relationships. Therefore, a radial-based integrated network based on the combination of composition and superposition of radial functions is developed to model FDM using a limited number of data points
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