Psychosocial variables associated with the co-occurrence of risky sexual behavior with alcohol consumption among university students

This study examined the association of theoretically guided and empirically identified psychosocial variables on the co-occurrence of risky sexual behavior with alcohol consumption among university students. The study utilized event analysis to determine whether risky sex occurred during the same event in which alcohol was consumed. Relevant conceptualizations included alcohol disinhibition, self-efficacy, and social network theories. Predictor variables included negative condom attitudes, general risk taking, drinking motives, mistrust, social group membership, and gender. Factor analysis was employed to identify dimensions of drinking motives. Measured risky sex behaviors were (a) sex without a condom, (b) sex with people not known very well, (c) sex with injecting drug users (IDUs), (d) sex with people without knowing whether they had a STD, and (e) sex with using drugs. A purposive sample was used and included 222 male and female students recruited from a major urban university. Chi-square analysis was used to determine whether participants were more likely to engage in risky sex behavior in different alcohol use contexts. These contexts were only when drinking, only when not drinking, and when drinking or not. The chi-square findings did not support the hypothesis that university students who use alcohol with sex will engage in riskier sex. These results added to the literature by extending other similar findings to a university student sample. For each of the observed risky sex behaviors, discriminant analysis methodology was used to determine whether the predictor variables would differentiate the drinking contexts, or whether the behavior occurred. Results from discriminant analyses indicated that sex with people not known very well was the only behavior for which there were significant discriminant functions. Gender and enhancement drinking motives were important constructs in the classification model. Limitations of the study and implications for future research, social work practice and policy are discussed. ^

Essays on international macroeconomics and conflict analysis

This dissertation addressed two broad problems in international macroeconomics and conflict analysis. The first problem in the first chapter looked at the behavior of exchange rate and its interaction with industry-level tradable goods prices for three countries, USA, UK and Japan. This question has important monetary policy implications. Here, I computed to what extent changes in exchange rate affected prices of consumer, producer, and export goods. I also studied the timing of these changes in these prices. My results, based on thirty-four industrial prices for USA, UK and Japan, supported the view that changes in exchange rates significantly affect prices of industrial and consumer goods. It also provided an insight to the underlying economic process that led to changes in relative prices. ^ In the second chapter, I explored the predictability of future inflation by incorporating shocks to exchange rates and clearly specified the transmission mechanisms that link exchange rates to industry-level consumer and producer prices. Employing a variety of linear and state-of-the-art nonlinear models, I also predicted growth rates of future prices. Comparing levels of inflation obtained from the above approaches showed superiority of the structural model incorporating the exchange rate pass-through effect. ^ The second broad issue addressed in the third chapter of the dissertation investigated the economic motives for conflict, manifested by rebellion and civil war for seventeen Latin American countries. Based on the analytical framework of Garfinkel, Skaperdas and Syropoulos (2004), I employed ordinal regressions and Markov switching for a panel of seventeen countries to identify trade and openness factors responsible for conflict occurrence and intensity. The results suggested that increased trade openness reduced high intensity domestic conflicts but overdependence on agricultural exports, along with a lack of income earning opportunities lead to more conflicts. Thereafter, using the Cox Proportional Hazard model I studied “conflict duration” and found that over-reliance on agricultural exports explained a major part of the length of conflicts in addition to various socio-political factors. ^

Occurrence and transformation of organomercury in the Florida Everglades

In this study, a new method was developed based on aqueous phenylation, purge-and-trap preconcentration, gas chromatography (GC) separation, and detection by atomic fluorescence spectrometry (AFS) or inductively coupled plasma mass spectrometry (ICPMS). This technique is suitable for simultaneous determination of trace or ultratrace levels of CH3Hg+ and CH3CH2Hg+ in environmental samples. Method detection limits were 0.03 ng/L for both CH3Hg+ and CH3CH2Hg+ when AFS was used as the detector and 0.02 and 0.01 ng/L for CH3Hg+ and CH 3CH2Hg+ with ICPMS, respectively. The new method has the additional benefits of being free from interference by Cl - and dissolved organic matter. Using the method developed, both CH3Hg+ and CH3CH2Hg+ were detected in a number of soil and sediment samples collected from the Florida Everglades. The identity of CH3CH2Hg+ was verified by purge-and-trap-GC/MS analysis. The possibility of analytical artifact was excluded by using stable isotope tracer technique in combination with ICPMS detection. CH3CH 2Hg+ in the soil samples analyzed was at ng/g level, similar to that of CH3Hg+. The prevalence of CH 3CH2Hg+ in the soil of the Florida Everglades suggests that ethylation plays an important role in the geochemistry of Hg in this wetland. Soil incubation and sawgrass culture experiments using stable isotope tracers revealed that CH3Hg+ was mainly produced by microbial activities under anaerobic conditions, agreeing well with the general understanding of methylation mechanisms of Hg in the environment. Ethylation of Hg was not confirmed in these experiments, indicating that ethylation of Hg most probably follows different mechanisms in comparison to methylation. Further experiments revealed that trace levels of ethyllead species were able to transfer ethyl group to Hg in both deionized water and freshwater matrixes, producing CH3CH2Hg+. This might partially account for the occurrence of CH3CH2Hg+ in the relatively pristine environment of the Florida Everglades.

Assessment of the occurrence and potential effects of pharmaceuticals and personal care products in South Florida waters and sediments

A LLE-GC-MS method was developed to detect PPCPs in surface water samples from Big Cypress National Park, Everglades National Park and Biscayne National Park in South Florida. The most frequently found PPCPs were caffeine, DEET and triclosan with detected maximum concentration of 169 ng/L, 27.9 ng/L and 10.9 ng/L, respectively. The detection frequencies of hormones were less than PPCPs. Detected maximal concentrations of estrone, 17β-estradiol, coprostan-3-ol, coprostane and coprostan-3-one were 5.98 ng/L, 3.34 ng/L, 16.5 ng/L, 13.5 ng/L and 6.79 ng/L, respectively. An ASE-SPE-GC-MS method was developed and applied to the analysis of the sediment and soil area where reclaimed water was used for irrigation. Most analytes were below detection limits, even though some of analytes were detected in the reclaimed water at relatively high concentrations corroborating the fact that PPCPs do not significantly partition to mineral phases. An online SPE-HPLC-APPI-MS/MS method and an online SPE-HPLC-HESI-MS/MS method were developed to analyze reclaimed water and drinking water samples. In the reclaimed water study, reclaimed water samples were collected from the sprinkler for a year-long period at Florida International University Biscayne Bay Campus, where reclaimed water was reused for irrigation. Analysis results showed that several analytes were continuously detected in all reclaimed water samples. Coprostanol, bisphenol A and DEET's maximum concentration exceeded 10 μg/L (ppb). The four most frequently detected compounds were diphenhydramine (100%), DEET (98%), atenolol (98%) and carbamazepine (96%). In the study of drinking water, 54 tap water samples were collected from the Miami-Dade area. The maximum concentrations of salicylic acid, ibuprofen and DEET were 521 ng/L, 301 ng/L and 290 ng/L, respectively. The three most frequently detected compounds were DEET (93%), carbamazepine (43%) and salicylic acid (37%), respectively. Because the source of drinking water in Miami-Dade County is the relatively pristine Biscayne aquifer, these findings suggest the presence of wastewater intrusions into the delivery system or the onset of direct influence of surface waters into the shallow aquifer.

Assessment of the occurrence and potential risks of pharmaceuticals and their metabolites in fish and water using liquid chromatography mass spectrometry

A comprehensive method for the analysis of 11 target pharmaceuticals representing multiple therapeutic classes was developed for biological tissues (fish) and water. Water samples were extracted using solid phase extraction (SPE), while fish tissue homogenates were extracted using accelerated solvent extraction (ASE) followed by mixed-mode cation exchange SPE cleanup and analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS). Among the 11 target pharmaceuticals analyzed, trimethoprim, caffeine, sulfamethoxazole, diphenhydramine, diltiazem, carbamazepine, erythromycin and fluoxetine were consistently detected in reclaimed water. On the other hand, caffeine, diphenhydramine and carbamazepine were consistently detected in fish and surface water samples. In order to understand the uptake and depuration of pharmaceuticals as well as bioconcentration factors (BCFs) under the worst-case conditions, mosquito fish were exposed to reclaimed water under static-renewal for 7 days, followed by a 14-day depuration phase in clean water. Characterization of the exposure media revealed the presence of 26 pharmaceuticals while 5 pharmaceuticals including caffeine, diphenhydramine, diltiazem, carbamazepine, and ibuprofen were present in the organisms as early as 5 h from the start of the exposure. Liquid chromatography ultra-high resolution Orbitrap mass spectrometry was explored as a tool to identify and quantify phase II pharmaceutical metabolites in reclaimed water. The resulting data confirmed the presence of acetyl-sulfamethoxazole and sulfamethoxazole glucuronide in reclaimed water. To my knowledge, this is the first known report of sulfamethoxazole glucuronide surviving intact through wastewater treatment plants and occurring in environmental water samples. Finally, five bioaccumulative pharmaceuticals including caffeine, carbamazepine, diltiazem, diphenhydramine and ibuprofen detected in reclaimed water were investigated regarding the acute and chronic risks to aquatic organisms. The results indicated a low potential risk of carbamazepine even under the worst case exposure scenario. Given the dilution factors that affect environmental releases, the risk of exposure to carbamazepine will be even more reduced.

Assessment of the occurrence and potential risks of antibiotics and their metabolites in South Florida waters using liquid chromatography tandem mass spectrometry

An automated on-line SPE-LC-MS/MS method was developed for the quantitation of multiple classes of antibiotics in environmental waters. High sensitivity in the low ng/L range was accomplished by using large volume injections with 10-mL of sample. Positive confirmation of analytes was achieved using two selected reaction monitoring (SRM) transitions per antibiotic and quantitation was performed using an internal standard approach. Samples were extracted using online solid phase extraction, then using column switching technique; extracted samples were immediately passed through liquid chromatography and analyzed by tandem mass spectrometry. The total run time per each sample was 20 min. The statistically calculated method detection limits for various environmental samples were between 1.2 and 63 ng/L. Furthermore, the method was validated in terms of precision, accuracy and linearity. ^ The developed analytical methodology was used to measure the occurrence of antibiotics in reclaimed waters (n=56), surface waters (n=53), ground waters (n=8) and drinking waters (n=54) collected from different parts of South Florida. In reclaimed waters, the most frequently detected antibiotics were nalidixic acid, erythromycin, clarithromycin, azithromycin trimethoprim, sulfamethoxazole and ofloxacin (19.3-604.9 ng/L). Detection of antibiotics in reclaimed waters indicates that they can't be completely removed by conventional wastewater treatment process. Furthermore, the average mass loads of antibiotics released into the local environment through reclaimed water were estimated as 0.248 Kg/day. Among the surface waters samples, Miami River (reaching up to 580 ng/L) and Black Creek canal (up to 124 ng/L) showed highest concentrations of antibiotics. No traces of antibiotics were found in ground waters. On the other hand, erythromycin (monitored as anhydro erythromycin) was detected in 82% of the drinking water samples (n.d-66 ng/L). The developed approach is suitable for both research and monitoring applications.^ Major metabolites of antibiotics in reclaimed wates were identified and quantified using high resolution benchtop Q-Exactive orbitrap mass spectrometer. A phase I metabolite of erythromycin was tentatively identified in full scan based on accurate mass measurement. Using extracted ion chromatogram (XIC), high resolution data-dependent MS/MS spectra and metabolic profiling software the metabolite was identified as desmethyl anhydro erythromycin with molecular formula C36H63NO12 and m/z 702.4423. The molar concentration of the metabolite to erythromycin was in the order of 13 %. To my knowledge, this is the first known report on this metabolite in reclaimed water. Another compound acetyl-sulfamethoxazole, a phase II metabolite of sulfamethoxazole was also identified in reclaimed water and mole fraction of the metabolite represent 36 %, of the cumulative sulfamethoxazole concentration. The results were illustrating the importance to include metabolites also in the routine analysis to obtain a mass balance for better understanding of the occurrence, fate and distribution of antibiotics in the environment. ^ Finally, all the antibiotics detected in reclaimed and surface waters were investigated to assess the potential risk to the aquatic organisms. The surface water antibiotic concentrations that represented the real time exposure conditions revealed that the macrolide antibiotics, erythromycin, clarithromycin and tylosin along with quinolone antibiotic, ciprofloxacin were suspected to induce high toxicity to aquatic biota. Preliminary results showing that, among the antibiotic groups tested, macrolides posed the highest ecological threat, and therefore, they may need to be further evaluated with, long-term exposure studies considering bioaccumulation factors and more number of species selected. Overall, the occurrence of antibiotics in aquatic environment is posing an ecological health concern.^

Analysis of fractured terrain using remote sensing and geographic information systems : establishing a correlation between fracture network properties and vegetation

This research analyzed the spatial relationship between a mega-scale fracture network and the occurrence of vegetation in an arid region. High-resolution aerial photographs of Arches National Park, Utah were used for digital image processing. Four sets of large-scale joints were digitized from the rectified color photograph in order to characterize the geospatial properties of the fracture network with the aid of a Geographic Information System. An unsupervised landcover classification was carried out to identify the spatial distribution of vegetation on the fractured outcrop. Results of this study confirm that the WNW-ESE alignment of vegetation is dominantly controlled by the spatial distribution of the systematic joint set, which in turn parallels the regional fold axis. This research provides insight into the spatial heterogeneity inherent to fracture networks, as well as the effects of jointing on the distribution of surface vegetation in desert environments.

The effects of biofeedback on the occurrence of urinary incontinence in patients following radical retropubic prostatectomy

Postprostatectomy incontinence can create a significant barrier to the attainment of optimal social and physical functioning postoperatively. The objective of this retrospective, descriptive study was to determine the effect of biofeedback on the incidence of urinary incontinence in men status post radical retropubic prostatectomy (RRP). All patients of a urologic practice who had a biofeedback session preoperatively, and two sessions postoperatively, were sent a survey to complete. Correlational analysis concluded that there was no significance (p > .05) between a subject's age, educational level, or adherence to biofeedback therapy, and their level of postprostatectomy incontinence. Of those subjects who participated (n = 46), 35% reported their urinary control as excellent, 50% reported good results, and 15% reported fair results. No subjects reported poor urinary control. Ninety-five percent of subjects said they would recommend the biofeedback treatment to a friend, and 88% felt that biofeedback had helped them attain their present level of urinary control.

Assessment of the Occurrence and Potential Risks of Pharmaceuticals and their Metabolites in Fish and Water Using Liquid Chromatography Mass Spectrometry

A comprehensive method for the analysis of 11 target pharmaceuticals representing multiple therapeutic classes was developed for biological tissues (fish) and water. Water samples were extracted using solid phase extraction (SPE), while fish tissue homogenates were extracted using accelerated solvent extraction (ASE) followed by mixed-mode cation exchange SPE cleanup and analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS). Among the 11 target pharmaceuticals analyzed, trimethoprim, caffeine, sulfamethoxazole, diphenhydramine, diltiazem, carbamazepine, erythromycin and fluoxetine were consistently detected in reclaimed water. On the other hand, caffeine, diphenhydramine and carbamazepine were consistently detected in fish and surface water samples. In order to understand the uptake and depuration of pharmaceuticals as well as bioconcentration factors (BCFs) under the worst-case conditions, mosquito fish were exposed to reclaimed water under static-renewal for 7 days, followed by a 14-day depuration phase in clean water. Characterization of the exposure media revealed the presence of 26 pharmaceuticals while 5 pharmaceuticals including caffeine, diphenhydramine, diltiazem, carbamazepine, and ibuprofen were present in the organisms as early as 5 h from the start of the exposure. Liquid chromatography ultra-high resolution Orbitrap mass spectrometry was explored as a tool to identify and quantify phase II pharmaceutical metabolites in reclaimed water. The resulting data confirmed the presence of acetyl-sulfamethoxazole and sulfamethoxazole glucuronide in reclaimed water. To my knowledge, this is the first known report of sulfamethoxazole glucuronide surviving intact through wastewater treatment plants and occurring in environmental water samples. Finally, five bioaccumulative pharmaceuticals including caffeine, carbamazepine, diltiazem, diphenhydramine and ibuprofen detected in reclaimed water were investigated regarding the acute and chronic risks to aquatic organisms. The results indicated a low potential risk of carbamazepine even under the worst case exposure scenario. Given the dilution factors that affect environmental releases, the risk of exposure to carbamazepine will be even more reduced.

Assessment of the Occurrence and Potential Risks of Antibiotics and their Metabolites in South Florida Waters Using Liquid Chromatography Tandem Mass Spectrometry

An automated on-line SPE-LC-MS/MS method was developed for the quantitation of multiple classes of antibiotics in environmental waters. High sensitivity in the low ng/L range was accomplished by using large volume injections with 10-mL of sample. Positive confirmation of analytes was achieved using two selected reaction monitoring (SRM) transitions per antibiotic and quantitation was performed using an internal standard approach. Samples were extracted using online solid phase extraction, then using column switching technique; extracted samples were immediately passed through liquid chromatography and analyzed by tandem mass spectrometry. The total run time per each sample was 20 min. The statistically calculated method detection limits for various environmental samples were between 1.2 and 63 ng/L. Furthermore, the method was validated in terms of precision, accuracy and linearity. The developed analytical methodology was used to measure the occurrence of antibiotics in reclaimed waters (n=56), surface waters (n=53), ground waters (n=8) and drinking waters (n=54) collected from different parts of South Florida. In reclaimed waters, the most frequently detected antibiotics were nalidixic acid, erythromycin, clarithromycin, azithromycin trimethoprim, sulfamethoxazole and ofloxacin (19.3-604.9 ng/L). Detection of antibiotics in reclaimed waters indicates that they can’t be completely removed by conventional wastewater treatment process. Furthermore, the average mass loads of antibiotics released into the local environment through reclaimed water were estimated as 0.248 Kg/day. Among the surface waters samples, Miami River (reaching up to 580 ng/L) and Black Creek canal (up to 124 ng/L) showed highest concentrations of antibiotics. No traces of antibiotics were found in ground waters. On the other hand, erythromycin (monitored as anhydro erythromycin) was detected in 82% of the drinking water samples (n.d-66 ng/L). The developed approach is suitable for both research and monitoring applications. Major metabolites of antibiotics in reclaimed wates were identified and quantified using high resolution benchtop Q-Exactive orbitrap mass spectrometer. A phase I metabolite of erythromycin was tentatively identified in full scan based on accurate mass measurement. Using extracted ion chromatogram (XIC), high resolution data-dependent MS/MS spectra and metabolic profiling software the metabolite was identified as desmethyl anhydro erythromycin with molecular formula C36H63NO12 and m/z 702.4423. The molar concentration of the metabolite to erythromycin was in the order of 13 %. To my knowledge, this is the first known report on this metabolite in reclaimed water. Another compound acetyl-sulfamethoxazole, a phase II metabolite of sulfamethoxazole was also identified in reclaimed water and mole fraction of the metabolite represent 36 %, of the cumulative sulfamethoxazole concentration. The results were illustrating the importance to include metabolites also in the routine analysis to obtain a mass balance for better understanding of the occurrence, fate and distribution of antibiotics in the environment. Finally, all the antibiotics detected in reclaimed and surface waters were investigated to assess the potential risk to the aquatic organisms. The surface water antibiotic concentrations that represented the real time exposure conditions revealed that the macrolide antibiotics, erythromycin, clarithromycin and tylosin along with quinolone antibiotic, ciprofloxacin were suspected to induce high toxicity to aquatic biota. Preliminary results showing that, among the antibiotic groups tested, macrolides posed the highest ecological threat, and therefore, they may need to be further evaluated with, long-term exposure studies considering bioaccumulation factors and more number of species selected. Overall, the occurrence of antibiotics in aquatic environment is posing an ecological health concern.