Multivariable Control and Online State Estimation of an FCC Unit

The purpose of this paper is to realize multivariable control , tuning and online state estimation of some parameters of the FCC unit . We implemented two control structures with the manipulated variables being the air inlet flow rate in the regenerator, the regenerated catalyst flow rate and the feed flow rate and, the controlled variable being the temperatures in the riser and in the densed bed of the regenerator. A novel four transfer function is built and used for controllability studies. Hard constraints are imposed with respect to the manipulated variables. Simulation results show that the configuration made of two inputs and two outputs is more easy to tune for control purposes. Althought there are important dynamic interactions between the components of the FCC and important nonlinearities, linear model predictive control is able to maintain a smooth multivariable control of the plant, while taking into account the different constraints. Tuning strategy is implemented to improve the tracking of the set point. Online state estimation is carried out with the use of the extended Kalman filter. The estimation gives results that can be used for monitoring purposes even in the presence of model mismatch

Declining prevalence of probable depression among patients presenting for antiretroviral therapy in rural Uganda: the role of early treatment initiation.

Little is known about trends in depression at antiretroviral therapy (ART) initiation among people living with HIV (PLHIV) in low- and middle-income countries. We used data from an ongoing cohort of treatment-naïve PLHIV in rural Uganda to estimate secular trends in depression among PLHIV at ART initiation. We fitted linear regression models with depression symptom severity as the outcome variable and year of cohort entry (2005-2012) as the explanatory variable, adjusting for socio-demographic variables and assessing physical health score, body mass index (BMI), and CD4 count as potential mediators of a secular trend in depression symptom severity. There was a statistically significant negative association between year of entry and depression symptom severity, suggesting a 3.1 % relative decline in the mean depression symptom severity score at ART initiation in each year of study recruitment after the first year. This trend remained statistically significant after inclusion of baseline socio-demographic characteristics to the model and appeared to be driven by improved physical health scores, but not CD4 count or BMI

Persistent HIV-related stigma in rural Uganda during a period of increasing HIV incidence despite treatment expansion

ObjectiveProgramme implementers have argued that the increasing availability of antiretroviral therapy (ART) will reduce the stigma of HIV. We analyzed data from Uganda to assess how HIV-related stigma has changed during a period of ART expansion.DesignSerial cross-sectional surveys.MethodsWe analyzed data from the Uganda AIDS Rural Treatment Outcomes study during 2007-2012 to estimate trends in internalized stigma among people living with HIV (PLHIV) at the time of treatment initiation. We analyzed data from the Uganda Demographic and Health Surveys from 2006 to 2011 to estimate trends in stigmatizing attitudes and anticipated stigma in the general population. We fitted regression models adjusted for sociodemographic characteristics, with year of data collection as the primary explanatory variable.ResultsWe estimated an upward trend in internalized stigma among PLHIV presenting for treatment initiation [adjusted b = 0.18; 95% confidence interval (CI), 0.06-0.30]. In the general population, the odds of reporting anticipated stigma were greater in 2011 compared with 2006 [adjusted odds ratio (OR) = 1.80; 95% CI, 1.51-2.13], despite an apparent decline in stigmatizing attitudes (adjusted OR = 0.62; 95% CI, 0.52-0.74).ConclusionInternalized stigma has increased over time among PLHIV in the setting of worsening anticipated stigma in the general population. Further study is needed to better understand the reasons for increasing HIV-related stigma in Uganda and its impact on HIV prevention efforts

The influence of partnership on contraceptive use among HIV-infected women accessing antiretroviral therapy in rural Uganda.

ObjectiveThe objective was to determine individual and dyadic factors associated with effective contraceptive use among human immunodeficiency virus (HIV)-infected women accessing antiretroviral therapy (ART) in rural Uganda.Study designHIV-infected women enrolled in the Uganda AIDS Rural Treatment Outcomes cohort completed questionnaires (detailing sociobehavioral characteristics, sexual and reproductive history, contraceptive use, fertility desires) and phlebotomy (October 2011-March 2013). We describe prevalence of effective contraceptive use (i.e., consistent condom use and/or oral contraceptives, injectable hormonal contraception, intrauterine device, female sterilization) in the previous 6 months among sexually active, nonpregnant women (18-40 years). We assessed covariates of contraceptive use using multivariable logistic regression.ResultsA total of 362 women (median values: age 30 years, CD4 count 397 cells/mm(3), 4.0 years since ART initiation) were included. Among 284 sexually active women, 50% did not desire a(nother) child, and 51% had a seroconcordant partner. Forty-five percent (n=127) reported effective contraceptive use, of whom 57% (n=72) used condoms, 42% (n=53) injectables, 12% (n=15) oral contraceptives and 11% (n=14) other effective methods. Dual contraception was reported by 6% (n=8). Only "partnership fertility desire" was independently associated with contraceptive use; women who reported that neither partner desired a child had significantly increased odds of contraceptive use (adjusted odds ratio: 2.40, 95% confidence interval: 1.07-5.35) compared with women in partnerships where at least one partner desired a child.ConclusionsLess than half of sexually active HIV-infected women accessing ART used effective contraception, of which 44% (n=56) relied exclusively on male condoms, highlighting a continued need to expand access to a wider range of longer-acting female-controlled contraceptive methods. Association with partnership fertility desire underscores the need to include men in reproductive health programming.Implications statementLess than half of sexually active HIV-infected women accessing ART in rural Uganda reported using effective contraception, of whom 44% relied exclusively on the male condom. These findings highlight the need to expand access to a wider range of longer-acting, female-controlled contraceptive methods for women seeking to limit or space pregnancies. Use of contraception was more likely when both the male and female partner expressed concordant desires to limit future fertility, emphasizing the importance of engaging men in reproductive health programming

Health equity and health system strengthening – Time for a WHO re-think

The pursuit of health equity is foundational to the global health enterprise. But while moral concerns over health inequities can galvanise political commitment, how such concerns can or should translate into practice remains less clear. This paper reviews evolving ways that equity goals have featured in key World Health Organization (WHO)-related policy documents, before discussing the heuristic value and empirical traction that the concept of equity can bring to the health system strengthening (HSS) agenda. We argue that while health equity is often presented as the overarching goal of HSS, in practice this is typically circumscribed to the provision of healthcare services. Although healthcare equity is important, we suggest that this narrow focus risks losing sight of the structural political, social and economic drivers of health and health inequities, as well as the broader contexts of care and complex socio-political mechanisms through which health systems are strengthened. Drawing on new lines of empirical inquiry, we propose that broadening the equity lens for HSS ­offers exciting opportunities to put health systems at the heart of a more ambitious equity agenda in global health