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In clinical and epidemiological studies, when the time-to-event(s) and the longitudinal outcomes are associated, modelling them separately may give biased estimates. A joint modelling approach is required to obtain unbiased results and to evaluate their association. In the joint model, a subject may be exposed to more than one type of failure event (competing risks). Considering the competing event as an independent censoring of the time-to-event process may underestimate the true survival probability and give biased results. Within the joint model, longitudinal outcomes may have nonlinear (irregular) trajectories over time and exhibit skewness with heavy tails. Accordingly, fully parametric mixed-effect models may not be flexible enough to model this type of complex longitudinal data. In addition, assuming a Gaussian distribution for model errors may be too restrictive to adequately represent within-individual variations and may lack robustness against deviation from distributional assumptions. To simultaneously overcome these issues, in this paper, we presented semiparametric joint models for competing risks failure time and skewed-longitudinal data by using a smoothing spline approach and a multivariate skew-t distribution. We also considered different parameterization approaches in the formulation of joint models and used a Bayesian approach to make the statistical inference. We illustrated the proposed methods by analyzing real data on a chronic kidney disease. To evaluate the performance of the methods, we also carried out simulation studies. The results of both the application and simulation studies revealed that the joint modelling approach proposed in this study performed well when the semiparametric, random-effects parameterization, and skew-t distribution specifications were taken into account.

Information on dietary intakes of Jamaican immigrants in the United States is sparse. Understanding factors that influence diet is important since diet is associated with chronic diseases. This study examined the association between acculturation, socio-cultural factors, and dietary pattern among Jamaican immigrants in Florida. Jamaican persons 25–64years who resided in two South Florida counties were recruited for participation. A health questionnaire that assessed acculturation, dietary pattern, and risk factors for cardiovascular disease was administered to participants. Generalized Estimating Equations were used to determine associations. Acculturation score was not significantly associated with dietary intake pattern (β=−0.02 p=0.07). Age at migration was positively associated with traditional dietary pattern (β=0.02 p

Objective: To assess whether conversion from twin to singleton pregnancy following the demise of a co-twin influences survival. Methods: This retrospective study compared the risk for neonatal, post-neonatal and infant death for converted co-twins versus unconverted co-twins using the US matched multiple file dataset for the period 1995–2000. We also examined the same risks for converted versus same-quantile co-twins, hazard ratios (HR) and 95% confidence intervals (CI) were computed using Cox Proportional Hazards models. Results: The risk for neonatal (HR = 0.18, 95% CI: 0.09–0.34 and HR = 0.69, 95% CI: 0.50–0.96) and infant death (HR = 0.22, 95% CI: 0.12–0.42 and HR = 0.57, 95% CI: 0.42–0.77) were significantly lower for converted twins than for unconverted twins and same-quantile twins, respectively. For black compared to white, the risk for post-neonatal death increased by 89% (HR = 1.89, 95% CI = 1.03, 3.48), and 79% (HR = 1.79, 95% CI = 1.53, 2.09) for converted vs. unconverted and converted vs. same-quantile, respectively. For converted black, the risk for neonatal death decreased by 17% (HR = 0.83, 95% CI = 0.73–0.93) as compared to unconverted. Conclusions: Risks for all mortality types were lower among converted co-twins than their unconverted or same-quantile counterparts. The lower neonatal and higher post-neonatal mortality among black require future research.

The obstetric consequences of abnormal thyroid function during pregnancy have been established. Less understood is the influence of maternal thyroid autoantibodies on infant outcomes. The objective of this study was to examine the influence of maternal thyroperoxidase (TPO) status on fetal/infant brain and body growth. Six-hundred thirty-one (631) euthyroid pregnant women were recruited from prenatal clinics in Tampa Bay, Florida, and the surrounding area between November 2007 and December 2010. TPO status was determined during pregnancy and fetal/infant brain and body growth variables were assessed at delivery. Regression analysis revealed maternal that TPO positivity was significantly associated with smaller head circumference, reduced brain weight, and lower brain-to-body ratio among infants born to TPO+ white, non-Hispanic mothers only, distinguishing race/ethnicity as an effect modifier in the relationship. No significant differences were noted in body growth measurements among infants born to TPO positive mothers of any racial/ethnic group. Currently, TPO antibody status is not assessed as part of the standard prenatal care laboratory work-up, but findings from this study suggest that fetal brain growth may be impaired by TPO positivity among certain populations; therefore autoantibody screening among high-risk subgroups may be useful for clinicians to determine whether prenatal thyroid treatment is warranted.

In North Carolina, we analyzed cumulative data for tuberculosis (TB) from 1980 through 1999 to determine trends in incidence, population subgroups at risk, and implications for health policy-makers. The overall incidence rates declined significantly over the study period (p = 0.0001). This decline correlates strongly with an increase in TB patients receiving directly observed therapy. Males have approximately twice the risk for disease, and persons 65 years of age are at the highest risk. For every Caucasian with TB, six blacks, six Hispanics, and eight Asians have the disease. TB incidence rates are declining in all other population subgroups but increasing in foreign-born and Hispanic persons.

In this study, we have attempted to assess how gender affects urban and peri-urban agriculture in Ethiopia. On the basis of a household survey, data were collected from 54 urban farmer households using a structured questionnaire, and nine case studies and focus group discussions were randomly selected from three sub-cities in Addis Ababa and one district in the Oromia Special Zone surrounding Finfine. Data from both primary and secondary sources were employed to generate the paper. The findings revealed that the most common types of agribusiness in urban and peri-urban areas were cultivating grass and vegetable crops. It also suggests that those involved in urban and peri-urban agriculture are creating job opportunities and extra income for middle- and low-income people. The decision-makers therefore must implement sustainable livelihood systems for these very poor communities, which reside in peri-urban and urban centers in the area. [ABSTRACT FROM AUTHOR]

Heavy metals (HMs) in wastewater could pose a significant challenge to biological treatment systems such as in an Up-flow Anaerobic Sludge Blanket Reactor (UASBr) as well as Trickling Filter (TF) performances. These HMs are associated with retention and accumulation of solid precipitates, limitting solid-liquid separation, disrupting biochemical processes, which ultimately brings environmental risks, such as soil contamination and public health issues, dominantly due to the inhibited activities of degrading microorganisms. A cross-sectional study was applied to investigate the levels of HMs in sewage using composite and grab sampling taken from Kaliti Wastewater Treatment Plant and the samples were analyzed using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The HMs concentrations in mean±(SD) were, Ag ranges from below detection level (BDL) to 63.5 (13.5) mg/kg; Ba 60 (4.47) μg/l to 1291(58.5) mg/kg; Al, BDL to 2358.5(662.5) mg/kg; Cd 0 μg/l to 0.35(0.15) mg/kg; Cr 0 μg/l to 10.5(0.7) mg/kg; Cu 0 μg/l to 23.9(1.2) mg/kg; Zn 5.45 (12.3) to 165(5.4) mg/kg, and Mn 165 (49.5) μg/l to 92.5(3.8) mg/kg. Results indicated that Kaliti Wastewater Treatment Plant was effective in removing pollutants and thereby meeting local and international discharge limits. The plant was also found to be effective in removing Al, Cd, Cu, and Cr, but not in removing Ba and Zn. However, a real time data collection and monitoring of seasonal physicochemical parameters and HM levels in the wastewater treatment plant is suggested useful.

In most developing countries, municipal sewage sludge end-use practices appear unsustainable; rather, it poses environmental concerns. This study examined the potential of vermicomposting of municipal sewage sludge and its blend with other biowaste for agricultural application. Using a response surface methodology and the Box–Behnken design in Design Expert Software (Version 10.0.7), the current study optimized the moisture content (60–90%), turning frequency (1–3 turnings/week), and substrate mixing ratios (50:50 to 80:20 wt.%) to maximize the content of nitrogen, phosphorus, and potassium. As a result, an optimal moisture content (72%), substrate mixing ratio (72.34:27.6 wt.%), and turning frequency (2 per week), producing a promising-quality vermicompost with a maximum yield of nitrogen (2.76%), phosphorus (1.80%), and potassium (1.88%) is achieved. Thus, vermicomposting can effectively turn the concerning municipal sewage sludge into useful agricultural input for its sustainable management. HIGHLIGHTS Optimal vermicomposting conditions were achieved through parameter optimization, including moisture content, mixing ratio, and turning frequency.; High-quality vermicompost was harvested from municipal sewage sludge and amended with another biowaste (coffee husks and cow dung).; The physicochemical and microbial properties of the vermicompost were analyzed for use as organic fertilizer.;

Abstract Recently, water scarcity, world population rise and urbanization are causing desalting of seawater. Membrane separation processes such as reverse osmosis are applied for desalination over the conventional mass transfer techniques. For instance, reverse osmosis accounts for the treatment of nearly 1% of the world water supply and its applications are increasing with time. However, cost, technical management and efficiency are challenging aspects. Hence, membrane fouling, direct and indirect investment costs, and permeate quality are the major hurdles encountered. Toward solving these problems, various studies are being conducted including varying membrane operating conditions and separation methodologies whereby ion-exchange–reverse osmosis hybrids and the coupling of two or more other membrane filtration techniques can be mentioned. Apparently, most of the hybrid techniques targeted for the selective removal of a pollutant. Hence, ion exchange–reverse osmosis is the most applied hybrid process particularly for boron removal due to its public and environmental health impact. Despite that, there is no current and comprehensive review that bridged the piece by piece and fragmented reports. In this review, desalination–ion-exchange coupling with other membrane filtration is explored in detail and the recent advances in composite membrane material synthesis are uncovered. Further, the status, cost and future potential of hybrid membranes are discussed and gaps are identified for future research.

The objective of this study was to evaluate the treatment efficiency of a coupled stillage anaerobic digestion, which was performed in scoria-packed continuous reactors and following aerobic degradation. The optimum organic loading rate was determined for the continuous anaerobic digestion of a molasses ethanol distillery stillage with and without wet air feed pretreatment. The pretreatment of the molasses ethanol distillery stillage brought a significantly higher chemical oxygen demand removal in anaerobic digestion with an increased loading rate of 2000 mg/L d when compared with the raw stillage. The results also showed a complete removal of the biological oxygen demand following the coupling of anaerobic digestion with aerobic degradation. During the later stillage aerobic treatment, 68% of the chemical oxygen demand was removed within 8 hours of retention time. Despite the color, the removal of organics in stillage due to integrating wet air pretreatment, continuous anaerobic digestion, and aerobic degradation was successful. The pretreatment and hybrid technique also appears as a promising technique toward the sustainable management of stillage, thereby meeting discharge limit set for the ethanol industry by regulators.

The effect of a mild, wet air pretreatment and the subsequent anaerobic digestion (AD) was examined on the recovery of a complex and toxic molasses ethanol distillery stillage. The biogas yield and organics removal due to pretreatment were compared with the raw stillage AD. The application of a scoria support in this industrial residue AD process stability was also assessed. Consequently, a statistically significant cumulative specific methane recovery difference (p-value = 0.000) with an almost complete biological oxygen demand (BOD) removal and a significant chemical oxygen demand (COD) reduction, which were 100% and 92% respectively were achieved. Additionally, the biogas recovery rate was hastened due to pretreatment. The application of scoria, whose property has been instrumentally inspected, has helped stabilize the pH in the AD systems. In a comparative approach, this study suggests the energy benefit and an ecofriendly discharge of stillage by the ethanol industry towards sustainability.

The role of behavior observation in theory-driven prevention intervention trials is examined. A model is presented to guide choice of strategies for the measurement of five core elements in theoretically informed, randomized prevention trials: (1) training intervention agents, (2) delivery of key intervention conditions by intervention agents, (3) responses of clients to intervention conditions, (4) short-term risk reduction in targeted client behaviors, and (5) long-term change in client adjustment. It is argued that the social processes typically thought to mediate interventionist training (Element 1) and the efficacy of psychosocial interventions (Elements 2 and 3) may be powerfully captured by behavior observation. It is also argued that behavior observation has advantages in the measurement of short-term change (Element 4) engendered by intervention, including sensitivity to behavior change and blinding to intervention status. [ABSTRACT FROM AUTHOR]