Evidence of the heterogeneous market hypothesis using wavelet multi -resolution analysis

In finance literature many economic theories and models have been proposed to explain and estimate the relationship between risk and return. Assuming risk averseness and rational behavior on part of the investor, the models are developed which are supposed to help in forming efficient portfolios that either maximize (minimize) the expected rate of return (risk) for a given level of risk (rates of return). One of the most used models to form these efficient portfolios is the Sharpe's Capital Asset Pricing Model (CAPM). In the development of this model it is assumed that the investors have homogeneous expectations about the future probability distribution of the rates of return. That is, every investor assumes the same values of the parameters of the probability distribution. Likewise financial volatility homogeneity is commonly assumed, where volatility is taken as investment risk which is usually measured by the variance of the rates of return. Typically the square root of the variance is used to define financial volatility, furthermore it is also often assumed that the data generating process is made of independent and identically distributed random variables. This again implies that financial volatility is measured from homogeneous time series with stationary parameters. In this dissertation, we investigate the assumptions of homogeneity of market agents and provide evidence for the case of heterogeneity in market participants' information, objectives, and expectations about the parameters of the probability distribution of prices as given by the differences in the empirical distributions corresponding to different time scales, which in this study are associated with different classes of investors, as well as demonstrate that statistical properties of the underlying data generating processes including the volatility in the rates of return are quite heterogeneous. In other words, we provide empirical evidence against the traditional views about homogeneity using non-parametric wavelet analysis on trading data, The results show heterogeneity of financial volatility at different time scales, and time-scale is one of the most important aspects in which trading behavior differs. In fact we conclude that heterogeneity as posited by the Heterogeneous Markets Hypothesis is the norm and not the exception.

An evaluation of depression, self-efficacy, satisfaction with life and perceived access to medical care across stages of HIV infection

This survey was designed to identify the incidence and scope of depression, satisfaction with life, self-efficacy and perceived access to medical care for those who are infected with the HIV virus. It also determined whether or not factors such as sexual orientation, ethnicity and socioeconomic status are intervening variables with respect to mental health issues. Subjects were recruited through a purposive sample from South Florida. A total of 871 surveys were used in the analysis. The overall response rate was nearly 90%. The incidence of depression was found to be higher than 75% across all stages of HIV infection. Furthermore, the incidence of depression increased as HIV disease progressed. Satisfaction with life and for the most part, self efficacy were found to decrease slightly as HIV disease progressed. Significant variance in depression, life satisfaction and self efficacy were found across stages of HIV infection. No significant differences between groups that were HIV infected were found for depression, life satisfaction and self efficacy. The severity of depression was found to vary significantly with self efficacy, life satisfaction and access to medical care but not with socioeconomic status. Life satisfaction was found to vary significantly with socioeconomic status, depression and self efficacy but not with access to medical care. Self-efficacy was found to vary significantly with socioeconomic status, depression and life satisfaction but not with access to medical care. Gender and ethnicity were not found to be significant precedent variables in depression for HIV infected individuals. Sexual orientation was found to be a significant precedent variable for depression, life satisfaction and self efficacy.

The predictive power of homework assignments on student achievement in grade three

Homework has been a controversial issue in education for the past century. Research has been scarce and has yielded results at both ends of the spectrum. This study examined the relationship between homework performance (percent of homework completed and percent of homework correct), student characteristics (SAT-9 score, gender, ethnicity, and socio-economic status), perceptions, and challenges and academic achievement determined by the students' average score on weekly tests and their score on the FCAT NRT mathematics assessment. ^ The subjects for this study consisted of 143 students enrolled in Grade 3 at a suburban elementary school in Miami, Florida. Pearson's correlations were used to examine the associations of the predictor variables with average test scores and FCAT NRT scores. Additionally, simultaneous regression analyses were carried out to examine the influence of the predictor variables on each of the criterion variables. Hierarchical regression analyses were performed on the criterion variables from the predictor variables. ^ Homework performance was significantly correlated with average test score. Controlling for the other variables homework performance was highly related to average test score and FCAT NRT score. ^ This study lends support to the view that homework completion is highly related to student academic achievement at the lower elementary level. It is suggested that at the elementary level more consideration be given to the amount of homework completed by students and to utilize the information in formulating intervention strategies for student who may not be achieving at the appropriate levels. ^

Ecosystem structure in disturbed and restored subtropical seagrass meadows

Shallow seagrass ecosystems frequently experience physical disturbance from vessel groundings. Specific restoration methods that modify physical, chemical, and biological aspects of disturbances are used to accelerate recovery. This study evaluated loss and recovery of ecosystem structure in disturbed seagrass meadows through plant and soil properties used as proxies for primary and secondary production, habitat quality, benthic metabolism, remineralization, and nutrient storage and exchange. The efficacy of common seagrass restoration techniques in accelerating recovery was also assessed. Beyond removal of macrophyte biomass, disturbance to seagrass sediments resulted in loss of organic matter and stored nutrients, and altered microbial and infaunal communities. Evidence of the effectiveness of restoration actions was variable. Fill placement prevented additional erosion, but the resulting sediment matrix had different physical properties, low organic matter content and nutrient pools, reduced benthic metabolism, and less primary and secondary production relative to the undisturbed ecosystem. Fertilization was effective in increasing nitrogen and phosphorus availability in the sediments, but concurrent enhancement of seagrass production was not detected. Seagrass herbivores removed substantial seagrass biomass via direct grazing, suggesting that leaf loss to seagrass herbivores is a spatially variable but critically important determinant of seagrass transplanting success. Convergence of plant and sediment response variables with levels in undisturbed seagrass meadows was not detected via natural recovery of disturbed sites, or through filling and fertilizing restoration sites. However, several indicators of ecosystem development related to primary production and nutrient accumulation suggest that early stages of ecosystem development have begun at these sites. This research suggests that vessel grounding disturbances in seagrass ecosystems create more complex and persistent resource losses than previously understood by resource managers. While the mechanics of implementing common seagrass restoration actions have been successfully developed by the restoration community, expectations of consistent or rapid recovery trajectories following restoration remain elusive.

The effect of domestic credit in the economic *development process

A commonly held view is that creation of excessive domestic credit may lead to inflation problems, however, many economists uphold the possibility that, generous domestic credit under appropriate conditions will result in increases of output. This hypothesis is examined for Japan and Colombia for the period 1950-1993.^ Domestic credit theories are reviewed since the times of Thornton and Smith, until the recent times of Lewis, McKinnon, Stiglitz and of Japanese economists like K. Emi, Tachi R. and others. It is found that in Japan of the Post-War period, efficient financial markets and the decisive role of the government in orienting investment decisions seem to have influenced positively the effectiveness of domestic credit as an output-stimulating variable. On the contrary, in Colombia the absence of the above features seems to explain why domestic credit is not very effective as an output-stimulating variable.^ Multiple regression analyses show that domestic credit is a strong explanatory variable for output increases in Japan and a weak one for Colombia's case in the studied period. For Japan the correlation depicts a positive relationship between the two variables with a decreasing rate very similar to a typical production function. Moreover, the positive decreasing rate is confirmed if net domestic credit is used in the correlations. For Colombia a positive relationship is also found when accumulated domestic credit is used, but, if net domestic credit is the source of correlations, the positive decreasing rate is not obtained.^ Granger causality tests determined causality from domestic credit to output for Japan and no-causality for Colombia at the 1% significance level; the differences are explained by: (1) The low development level of the financial system in Colombia. (2) The nonexistence of consistent domestic credit policy to foster economic development. (3) The lack of an authoritative orientation in the allocation of financial resources and the nonexistence of long range industrialization programs in Colombia that could channel productively credit resources. For the system of equations relating domestic credit and exports, the Granger causality tests determined no-causality between domestic credit and exports for both Japan and Colombia also at the 1% significance level. ^

The influence of neurocognitive impairment, alcohol and other drug (AOD) use, and psychosocial factors on antiretroviral treatment adherence, service utilization and viral load among HIV-seropositive adults

Among people living with HIV (PLWH), adherence to antiretroviral therapy (ART) can be affected by problems of neurocognitive (NC) impairment, stress, alcohol and other drug (AOD) abuse, and other barriers. The aims of this research were to: (1) examine factors associated with NC impairment, (2) explore relationships between psychosocial variables with ART adherence and viral load (VL), and (3) evaluate the efficacy of an evidence-based intervention in improving ART adherence, increasing service utilization, and decreasing VL. The first study (n=370) was cross sectional and used structural equation modeling to test whether AOD use, years living with HIV, and time from HIV diagnosis to seeking care were associated with poorer NC functioning. The second study (n=246) used similar methods to test the hypothesis that stress, barriers to adherence, NC impairment, poor social support, and AOD use were related to lower VL mediated by ART adherence. The third study (n=243) evaluated an evidence-based, eight-session program to improve ART adherence, reduce VL, and increase service utilization in a randomized controlled trial. Study participants were PLWH living in South Florida, 18 to 60 years old, with a history of alcohol abuse enrolled from January 2009 through November 2012. Secondary analysis of available data showed: (1) scores on interference with executive functioning increased by 0.32 for each day of marijuana use and 1.18 for each year living with HIV, but no association was found between alcohol use and NC functioning; (2) each barrier to adherence was associated with a 10% decrease in adherence to ART and a 0.42 unit increase in VL (log10) and the relationship between barriers and VL was partially mediated by ART adherence; (3) participants in the evidence-based program were more likely than the comparison group to report an undetectable VL (OR=2.25, p<0.01) at 6 months, but not 3 months, post-intervention. Psychosocial factors affect VL, but ART adherence is essential in achieving an undetectable VL in PLWH.