Concurrent Patterns Research Articles

Age-disparity, sexual connectedness and HIV infection in disadvantaged communities around Cape Town, South Africa: a study protocol

BackgroundCrucial connections between sexual network structure and the distribution of HIV remain inadequately understood, especially in regard to the role of concurrency and age disparity in relationships, and how these network characteristics correlate with each other and other risk factors. Social desirability bias and inaccurate recall are obstacles to obtaining valid, detailed information about sexual behaviour and relationship histories. Therefore, this study aims to use novel research methods in order to determine whether HIV status is associated with age-disparity and sexual connectedness as well as establish the primary behavioural and socio-demographic predictors of the egocentric and community sexual network structures.Method/DesignWe will conduct a cross-sectional survey that uses a questionnaire exploring one-year sexual histories, with a focus on timing and age disparity of relationships, as well as other risk factors such as unprotected intercourse and the use of alcohol and recreational drugs. The questionnaire will be administered in a safe and confidential mobile interview space, using audio computer-assisted self-interview (ACASI) technology on touch screen computers. The ACASI features a choice of languages and visual feedback of temporal information. The survey will be administered in three peri-urban disadvantaged communities in the greater Cape Town area with a high burden of HIV. The study communities participated in a previous TB/HIV study, from which HIV test results will be anonymously linked to the survey dataset. Statistical analyses of the data will include descriptive statistics, linear mixed-effects models for the inter- and intra-subject variability in the age difference between sexual partners, survival analysis for correlated event times to model concurrency patterns, and logistic regression for association of HIV status with age disparity and sexual connectedness.DiscussionThis study design is intended to facilitate more accurate recall of sensitive sexual history data and has the potential to provide substantial insights into the relationship between key sexual network attributes and additional risk factors for HIV infection. This will help to inform the design of context-specific HIV prevention programmes.

Patterns of Alcohol and Drug Use Among Depressed Older Adults Seeking Outpatient Psychiatric Services

Alcohol and drug use and related problems may compromise depression treatment, and older adults may be especially at risk for poor outcomes. However, alcohol and drug use among older adults have not been studied in settings in which depression treatment is provided. This study examined the prevalence and clinical and demographic correlates of alcohol and drug use and misuse of prescription drugs among adults with depression seeking outpatient psychiatric care (excluding chemical dependency treatment). The sample included 154 older adults (age 60 years and older who scored ≥10 on the Beck Depression Inventory-II [BDI-II] at intake). Participants also completed alcohol and drug use questions and the Short Michigan Alcohol Screening Test. Recent alcohol and drug use, heavy episodic drinking, and history of alcohol-related problems were common. Alcohol use in the prior 30 days was reported by 53% of men and 50% of women. Cannabis use in the prior 30 days was reported by 12% of men and 4% of women; and misuse of sedatives in the prior 30 days was reported by 16% of men and 9% of women. In exact logistic regression, higher BDI-II score was associated with cannabis use (odds ratio = 15.8, 95% confidence interval = 2.0-734.0, exactp = 0.003). Older adults with depression are likely to present for treatment with a range of concurrent alcohol and drug use patterns, including cannabis use and misuse of prescription medication. Clinicians should evaluate depressed patients for substance use and related problems and consider appropriate interventions.

P1-S5.42 Prevalence of transitional and embedded concurrency within a prospective cohort of urban adolescent females

BackgroundStudies have found that concurrent sexual partnerships, as opposed to cumulative number of sex partners or serially monogamous partnerships play a pivotal role in rates of STI transmission. Different patterns...

P2-S1.16 Social influences on relationship fidelity and concurrency patterns among Latino adolescents in San Francisco

BackgroundOur previous research in San Francisco's Mission District, a predominantly Latino neighbourhood characterised by high immigration, poverty, and gang-related violence, highlighted diverse partnership patterns among youth and the role of...

The Role of Abandoned Channels as Refugia for Sustaining Pioneer Riparian Forest Ecosystems

In disturbance-prone ecosystems, organisms often persist in spatial refugia during stressful periods. A clear example is the colonization of abandoned river channels by pioneer riparian trees. Here, we examine the prominence of this establishment pathway for a foundation tree species (Fremont cottonwood, Populus fremontii) within the riparian corridor of a large river, the Sacramento River in central California. We quantified the total proportion of forest that initiated as a result of channel abandonment for a 160-km reach, analyzed concurrent patterns of tree establishment with floodplain accretion and sedimentation history, and developed a conceptual model of biogeomorphic evolution of abandoned channels. Historical air photo analysis indicated that stands associated with abandoned channels comprised more than 50% of the total extant cottonwood forest area. Tree-ring evidence showed that cottonwood stands commonly developed immediately following abandonment, and the recruitment window ranged from 4 to 40 years, but was less than 10 years at most sites. Rates of floodplain rise and fine sediment accumulation were high in young sites and decreased logarithmically over time. Together, these results suggest that abandoned channels are an important refuge for cottonwood recruitment, that the greatest opportunity for colonization occurs within a short period after the cutoff event, and that sedimentation processes influence the duration of the colonization window. On rivers where tree recruitment along the active channel is severely limited by hydrologic regulation and/or land management, abandoned channel refugia may play an even more important role in sustaining an ecologically functional riparian corridor. Preserving bank erosion, active meander corridors and forest regeneration zones created by cutoff events are therefore key conservation measures on shifting rivers.

Recognition of unnatural patterns in process control charts through combining two types of neural networks

Unnatural patterns in control charts associate a set of assignable causes in production process. Therefore, effective discrimination of these patterns has special importance in on-line statistical process control. In resent years, artificial neural networks because of their abilities in patterns recognition have been used to detect control charts patterns. The correct and precise recognition in a real-time is difficult, because control chart patterns are distorted by common cause variations that occur naturally in the manufacturing processes. Nearly the most of investigations based neural networks solely have emphasized the control chart patterns recognition and have not considered extraction of detailed information that is important for analysis of assignable causes. Moreover, some of the patterns simulator functions do not represent completely the real world behavior. This study presents a hybrid model, including two types of neural networks. The proposed model can detect and discriminate single and concurrent patterns, determine the major corresponding parameters and estimate the starting point of unnatural patterns. This model introduces a procedure for patterns simulation in variable and attribute qualitative characteristics control charts. In addition, this research improves and develops unnatural patterns generator functions. Numerical results indicate that the proposed model performs suitably and effectively.

Symbolic modular deadlock analysis

Methods in object-oriented concurrent libraries often encapsulate internal synchronization details. As a result of information hiding, clients calling the library methods may cause thread safety violations by invoking methods in an unsafe manner. This is frequently a cause of deadlocks. Given a concurrent library, we present a technique for inferring interface contracts that specify permissible concurrent method calls and patterns of aliasing among method arguments. In this work, we focus on deriving contracts that guarantee deadlock-free execution for the methods in the library. The contracts also help client developers by documenting required assumptions about the library methods. Alternatively, the contracts can be statically enforced in the client code to detect potential deadlocks in the client. Our technique combines static analysis with a symbolic encoding scheme for tracking lock dependencies, allowing us to synthesize contracts using a SMT solver. Additionally, we investigate extensions of our technique to reason about deadlocks in libraries that employ signaling primitives such as wait-notify for cooperative synchronization. Our prototype tool analyzes over a million lines of code for some widely-used Java libraries within an hour, thus demonstrating its scalability and efficiency. Furthermore, the contracts inferred by our approach have been able to pinpoint real deadlocks in clients, i.e. deadlocks that have been a part of bug-reports filed by users and developers of client code.

An Auto-Adaptive GA-PID Control Method Based on CMAC Net

This paper aimed at solving the difficulty of nonlinear process control by classical PID controller. The author structured a GA-PID controller taking advantage of the multipoint optimizing and fast compute speed of GA, which can get the optimal PID parameters by on-line turning. At the same time, the author introduced a CMAC feed-forward controller which make full use of the high precision to approach nonlinearly object of CMAC. Combine them, a concurrent pattern control method appear, which synthesize advantages of two controllers and is more fit for nonlinear process. The simulation result indicated that the method has high accuracy and good robustness.

Programming the cloud

Client + cloud computing is a disruptive, new computing platform, combining diverse client devices -- PCs, smartphones, sensors, and single-function and embedded devices -- with the unlimited, on-demand computation and data storage offered by cloud computing services such as Amazon's AWS or Microsoft's Windows Azure. As with every advance in computing, programming is a fundamental challenge as client + cloud computing combines many difficult aspects of software development. Systems built for this world are inherently parallel and distributed, run on unreliable hardware, and must be continually available -- a challenging programming model for even the most skilled programmers. How then do ordinary programmers develop software for the Cloud? This talk presents one answer, Orleans, a software framework for building client + cloud applications. Orleans encourages use of simple concurrency patterns that are easy to understand and implement correctly, building on an actor-like model with declarative specification of persistence, replication, and consistency and using lightweight transactions to support the development of reliable and scalable client + cloud software.

Parent-child relationship of directly measured physical activity.

BackgroundStudies on parent-child correlations of physical activity have been mixed. Few studies have examined concurrent temporal patterns of physical activity and sedentary behaviors in parents and children using direct measures. The purpose of this study was to examine parent-child activity correlations by gender, day of week, and time of day, using accelerometers - a method for direct assessment of physical activity.MethodsAccelerometers were used to assess physical activity and sedentary time in 45 fathers, 45 mothers and their children (23 boys, 22 girls, mean age 9.9 years) over the course of 4 days (Thursday - Sunday). Participants were instructed to wear accelerometers for 24 hours per day. Data from accelerometers were aggregated into waking hours on weekdays and weekends (6:00 am to midnight) and weekday after-school hours (3:00 - 7:00 pm).ResultsAcross the 4 days, the mean minutes per day of moderate-to-vigorous physical activity (MVPA) for fathers was 30.0 (s.d. = 17.3), for mothers was 30.1 (s.d. = 20.1) and for children was 145.47 (s.d. = 51.64). Mothers' and fathers' minutes of MVPA and minutes of sedentary time were positively correlated with child physical activity and sedentary time (all ps < .05, with the exception of mothers' and children's sedentary time on weekdays from 6 am to 12 am). Multivariate linear regression analyses resulted in significant effects between parents and children for MVPA across all time segments. For sedentary activity, significant associations were observed only between father and child on the weekend. Sedentary activity of parents and children were not related for other time segments. Models examining the associations of one or two parents with high levels of MVPA or sedentary time indicated a dose response increase in child activity relative to parent.ConclusionsGreater parental MVPA was associated with increased child MVPA. In addition, having two parents with higher levels of MVPA was associated with greater levels of activity in children. Sedentary time in children was not as strongly correlated with that of their parents. Findings lend support to the notion that to increase childhood activity levels it may be fruitful to improve physical activity among parents.

Concurrent partnerships, acute infection and HIV epidemic dynamics among young adults in Zimbabwe.

This paper explores the roles of acute infection and concurrent partnerships in HIV transmission dynamics among young adults in Zimbabwe using realistic representations of the partnership network and all published estimates of stage-specific infectivity. We use dynamic exponential random graph models to estimate partnership network parameters from an empirical study of sexual behavior and drive a stochastic simulation of HIV transmission through this dynamic network. Our simulated networks match observed frequencies and durations of short- and long-term partnerships, with concurrency patterns specific to gender and partnership type. Our findings suggest that, at current behavior levels, the epidemic cannot be sustained in this population without both concurrency and acute infection; removing either brings transmission below the threshold for persistence. With both present, we estimate 20-25% of transmissions stem from acute-stage infections, 30-50% from chronic-stage, and 30-45% from AIDS-stage. The impact of acute infection is strongly moderated by concurrency. Reducing this impact by reducing concurrency could potentially end the current HIV epidemic in Zimbabwe.

Concurrency by modularity

General purpose object-oriented programs typically aren't embarrassingly parallel. For these applications, finding enough concurrency remains a challenge in program design. To address this challenge, in the Panini project we are looking at reconciling concurrent program design goals with modular program design goals. The main idea is that if programmers improve the modularity of their programs they should get concurrency for free. In this work we describe one of our directions to reconcile these two goals by enhancing Gang-of-Four (GOF) object-oriented design patterns. GOF patterns are commonly used to improve the modularity of object-oriented software. These patterns describe strategies to decouple components in design space and specify how these components should interact. Our hypothesis is that if these patterns are enhanced to also decouple components in execution space applying them will concomitantly improve the design and potentially available concurrency in software systems. To evaluate our hypothesis we have studied all 23 GOF patterns. For 18 patterns out of 23, our hypothesis has held true. Another interesting preliminary result reported here is that for 17 out of these 18 studied patterns, concurrency and synchronization concerns were completely encapsulated in our concurrent design pattern framework.

Concurrent p16 methylation pattern as an adverse prognostic factor in multiple myeloma: a methylation-specific polymerase chain reaction study using two different primer sets

Disruption of cell cycle control genes, including p16, is known to contribute to the cancerogenesis of multiple myeloma (MM). We investigated the methylation status of p16 and its association with common cytogenetic changes, clinicolaboratory findings, and survival in MM. Methylation-specific polymerase chain reaction was performed in 99 newly diagnosed MM patients using two different sets of primers (p16M1 and p16M2). Four patterns of p16 promoter methylation were observed: (1) concurrent methylation of p16M1 and p16M2 (P1P2), 27.3%; (2) methylation of p16M1 alone (P1N2), 7.1%; (3) methylation of p16M2 alone (N1P2), 26.3%; and (4) no methylation (N1N2), 39.4%. Patients with p16P1P1 showed shorter survivals than those with the other methylation patterns (P1N2, N1P2, or N1N2; median survival, 12 vs. 43 months; P < 0.001), regardless of the treatment protocol. In a multivariate analysis, p16P1P2 was an independent prognostic factor of adverse outcome in MM. According to International Staging System (ISS), the study population could be divided into 21.2% (20/94) for stage I, 22.3% (21/94) for stage II, and 56.4% (53/94) for stage III (P = 0.003). ISS can divide patients into prognostic groups. Of note, in patients older than 60 years, ISS was not reflective of disease stage (P = 0.114). If p16P1P2 sets up as stage 4 of ISS, modified ISS could be a more reliable staging system irrespective of age in Korean MM patients (P = 0.003 and P = 0.004 in patients younger than 60 years and in patients older than 60 years, respectively). Our study suggests the potential use of p16 methylation status in predicting the outcome of MM patients and the applicability of demethylating agents in MM.

Glacial conditioning as an erosional driving force in the Central Alps

Unparalleled data availability in the European Alps has led to an ongoing debate about the driving mechanism behind the concurrent patterns of surface denudation and modern rock uplift. Analysis of stream channels reveals that oversteepened stream segments are primarily located in landscapes with strong glacial inheritance. This leads to a transient signal in the landscape, with the result that erosion is spatially focused by a combination of glacial conditioning and lithologic controls. We postulate that the effect of glacial forcing is a positive feedback cycle between erosion and rock uplift, driving rapid rates of both in the Alpine landscape. This mechanism may explain the observed increases in sediment flux since the late Pliocene.

Concurrent variations of water vapor and temperature corresponding to the interannual variation of precipitation in the North American Regional Reanalysis

The concurrent variation patterns of water vapor and temperature corresponding to the interannual variation of winter precipitation and the roles of change in atmospheric circulation are studied with the North American Regional Reanalysis. A very tight positive relationship between precipitation and relative humidity at interannual time scale is found from the large spatially sampled data set. On the basis of this relationship, the concurrent variations of water vapor and temperature between the wettest and the driest years are categorized into three patterns. The distribution of the patterns shows that more winter precipitation of wetter years corresponds to more water vapor but not lower temperature (moistening pattern) in high latitudes, lower temperature but not more water vapor (cooling pattern) in midlatitudes, and both more water vapor and lower temperature (moistening‐cooling pattern) in low latitudes. The characteristics and roles of change in atmospheric circulation from the driest years to the wettest years are analyzed for two selected areas. It is found that, around the selected cooling pattern (moistening pattern) area, the field of wind difference between the wettest years and the driest years is divergent (convergent). Dominated by this, the fields of differences in both heat flux and water vapor flux are divergent (convergent). This leads to the decreases (increases) of the heating and moistening rates and, thus, the characteristics of the cooling pattern (moistening pattern) area with cooling and drying (warming and moistening) from the driest years to the wettest years. This study suggests that, for interannual prediction of precipitation, temperature, in addition to water vapor, should also be considered.

Graph-Based Modelling of Concurrent Sequential Patterns

Structural relation patterns have been introduced recently to extend the search for complex patterns often hidden behind large sequences of data. This has motivated a novel approach to sequential patterns post-processing and a corresponding data mining method was proposed for Concurrent Sequential Patterns (ConSP). This article refines the approach in the context of ConSP modelling, where a companion graph-based model is devised as an extension of previous work. Two new modelling methods are presented here together with a construction algorithm, to complete the transformation of concurrent sequential patterns to a ConSP-Graph representation. Customer orders data is used to demonstrate the effectiveness of ConSP mining while synthetic sample data highlights the strength of the modelling technique, illuminating the theories developed.

Sexual Partner Concurrency and Sexual Risk Among Gay, Lesbian, Bisexual, and Transgender American Indian/Alaska Natives

American Indian and Alaska Natives suffer pervasive health disparities, including disproportionately high rates of HIV. Sexual network dynamics, including concurrency and sexual mixing patterns, are key determinants of HIV disparities. We analyzed data from the first national study of gay, lesbian, bisexual, and transgender American Indian and Alaska Natives to examine the prevalence of concurrency, sex and race of partners, and level of risk across different partnership patterns. Egocentric network data were analyzed at the level of the respondents, who were grouped according to the sex of their last 3 partners. Overall rates of HIV and concurrency were high in this population. HIV prevalence (34%) and cumulative prevalence of concurrency (55%) were highest among men who had sex with only men, while women who had sex with only women reported lower concurrency and HIV. Women who had sex with women and men also had high HIV prevalence (15%) and reported slightly higher concurrency risk and low condom use, making them effective bridge populations. The uniformly high rates of Native partner selection creates the potential for amplification of disease spread within this small community, while the high rates of selecting partners of other races creates the potential for bridging to other groups in the transmission network. These findings provide some of the first insights into sexual networks and concurrency among Native gay, lesbian, bisexual, and transgender populations and suggest that both men and women deserve attention in HIV prevention efforts at individual, dyadic and population levels.

Modelling of a Catalytic Micro-Reactor Coupling Endothermic Methane Reforming and Combustion

In this study the mathematical modelling of a catalytic microstructured plate reactor for the production of hydrogen was performed in 2D and 3D geometry. The proposed reacting system uses the heat generated by an exothermic reaction (combustion) to sustain endothermic reforming reactions. Therefore, it pertains to those devices useful for producing the feed for fuel cell system for the remote generation of electrical power. However, because of the compactness of the reacting system it can also be considered in the context of apparatus aiming at process intensification. Within this frame the catalytic contribution of both exothermic and endothermic reactions was modelled considering the classic Langmuir-Hinshelwood surface kinetic theory. The advantage of using a real 3D geometry configuration consists in the possibility of considering the importance of the entering and boundary effects with particular attention to fluid stagnation and heat hot spots. The trade off of such a choice is certainly the huge increase of computing time and/or of the power of the computing facility. With respect to other works performed with similar reactor geometry and reacting systems this does not use simplifying assumptions such as catalyst layers modeled by one-dimensional approach, fully developed laminar flow or transverse heat and mass transfer taken into account through lumped heat and mass transfer coefficients. Results of simulations presented here concentrates on the comparisons between results of: countercurrent (CTC) and concurrent (CNC) flow patterns of the reactant streams; of simulations carried out with 2D and 3D models and of the influence of the thickness of the catalytic layers on the reactor performance. Simulations indicates that CNC flow pattern of reactants streams allows a better performance of the reactor since positive temperature differences between the catalyst layers and the gas in the channels maintain along the whole reactor and, consequently, there are not heat flux inversions, which occur under CTC flow pattern. Results also showed that as concerns an adiabatic reactor, whatever the operating conditions, 2D and 3D models yield substantially the same results. Finally, modelling demonstrated that for a realistic catalyst layer configuration thicknesses larger than 50 µm are useless for enhancing the reactor performance. The feasibility of the model proposed may show its potential in fast and easy implementation of several combustion and reforming fuels so to significantly enhance the performance prediction of real processes.

Treatment of Talar Osteochondral Lesions in Athletes: Approaches for Treatment

Surface injuries to the talus are relatively common in athletes and may occur as a result of acute injury but are often evaluated in a subacute or chronic setting. The purpose of this manuscript is to outline the key elements to understanding osteochondral lesions of the talus and identify methods of evaluation and treatment for these injuries. Specific methods of treatment are discussed and outcomes emphasized. Concurrent deformities and ligament instability patterns are reviewed.

Polygyny, Concurrency, Its Impact and Lack of Impact on HIV

Evaluation of: Reniers G, Watkins S: Polygyny and the spread of HIV in sub-Saharan Africa: a case of benign concurrency. AIDS 24, 299–307 (2010). This ecological study aims to understand the role of concurrency on HIV in sub-Saharan Africa. The results showed a negative association between the prevalence of HIV and polygyny, independently of selected risk factors (e.g., age at sexual debut and extramarital sex). This reflects the potential protective role of this specific form of concurrency, which contrasts with the common understanding that concurrency favors the spread of HIV. More research is needed to understand how different concurrency patterns influence the global network structure, how they are associated with risk practices within partnerships and the motivation underlying concurrency. This is relevant for the design of intervention focusing on concurrency, to maximise impact and minimize the risk of negative compensatory risk behavior. These results illustrate a growing misinterpretation of early model results due to the underappreciation of the diversity of network structures and HIV epidemic sizes that can be produced when concurrency levels are high.