Evolution with Drifting Targets

We consider the question of the stability of evolutionary algorithms to gradual changes, or drift, in the target concept. We define an algorithm to be resistant to drift if, for some inverse polynomial drift rate in the target function, it converges to accuracy 1 -- \epsilon , with polynomial resources, and then stays within that accuracy indefinitely, except with probability \epsilon , at any one time. We show that every evolution algorithm, in the sense of Valiant (2007; 2009), can be converted using the Correlational Query technique of Feldman (2008), into such a drift resistant algorithm. For certain evolutionary algorithms, such as for Boolean conjunctions, we give bounds on the rates of drift that they can resist. We develop some new evolution algorithms that are resistant to significant drift. In particular, we give an algorithm for evolving linear separators over the spherically symmetric distribution that is resistant to a drift rate of O(\epsilon /n), and another algorithm over the more general product normal distributions that resists a smaller drift rate. The above translation result can be also interpreted as one on the robustness of the notion of evolvability itself under changes of definition. As a second result in that direction we show that every evolution algorithm can be converted to a quasi-monotonic one that can evolve from any starting point without the performance ever dipping significantly below that of the starting point. This permits the somewhat unnatural feature of arbitrary performance degradations to be removed from several known robustness translations

Age Differences in the Capacity of Visual Short-term Memory: Effects of Stimulus Type and Information Load

The goal of the current study was to examine age differences in visual information load and visual STM for two types of items, abstract and meaningful, as well as determine the impact of item type and information load on age-related reductions in STM. Two experiments tested the hypotheses that age differences are greater in visual search and visual short-term memory for abstract items, and that information load may not fully explain age differences in visual STM. Age differences in visual search were greater for abstract than meaningful items, but older adults showed equivalent age-related reductions in visual STM for the two classes. Information load was a better predictor of visual STM capacity than item type when we compared the two classes

Executive function in daily life: age-related influences of executive processes on instrumental activities of daily living

The current study of older adults used structural equation modeling (SEM) to examine the relationships between three executive processes underlying executive function (EF) (inhibition, task-switching, and updating in working memory), and two types of instrumental activities of daily living (IADLs) (self-report and performancebased). Experimental tasks of executive attention from the cognitive psychology literature and self-report or performance-based IADL tests from the medical literature were measured to create the latent constructs of interest (EF and IADL). Confirmatory factor analysis (CFA) was used to examine the construct validity of EF and IADL. Nested two-factor models of EF were compared to a three-factor model of EF. A nested, one-factor model of IADL was compared to a two-factor model of self-report and performance-based items. A three-factor model of inhibition, updating, and taskswitching was endorsed in favor of a two-factor model of EF. A two-factor model of self-report and performance-based provided the best fit to the data in the model of IADL. As predicted, when the latent variable relationships were analyzed, executive processes had a significant relationship with performance-based, but not self-report IADLs. In addition, and as predicted from the greater age differences seen on experimental measures of updating and task-switching, updating had a strong and significant relationship with performance-based IADL (.40), followed by task-switching (.22), and inhibition (.10). The results of this study uniquely show a direct relationship between executive processes and IADLs, thus demonstrating that experimental measures of EF have ecological utility. Further, these results point to areas of cognitive rehabilitation that may strategically impact older adults’ performance on daily life activities

Masculinity, Moral Atmosphere, and Moral Functioning of High School Football Players

In order to identify factors associated with on-field moral functioning among student athletes within the unique context of football, we examined masculine gender role conflict, moral atmosphere, and athletic identity. Using structural equation modeling to assess survey data from 204 high school football players, results demonstrated that moral atmosphere (i.e., the influence of coaches and teammates) was significantly associated with participants’ process of on-field moral functioning across the levels of judgment, intention, and behavior. Neither masculine gender role conflict nor athletic identity significantly predicted moral functioning, but the results indicated that participants’ identification with the athlete role significantly predicted conflict with socialized gender roles. Results suggest that in the aggressive and violent sport of football, coaches can have a direct influence on players’ moral functioning process. Coaches can also have an indirect effect by influencing all the players so that a culture of ethical play can be cultivated among teammates and spread from the top down

The Development of Whole Sporozoite Vaccines for Plasmodium falciparum Malaria

Each year malaria kills hundreds of thousands of people and infects hundreds of millions of people despite current control measures. An effective malaria vaccine will likely be necessary to aid in malaria eradication. Vaccination using whole sporozoites provides an increased repertoire of immunogens compared to subunit vaccines across at least two life cycle stages of the parasite, the extracellular sporozoite, and intracellular liver stage. Three potential whole sporozoite vaccine approaches are under development and include genetically attenuated parasites, radiation attenuated sporozoites, and wild-type sporozoites administered in combination with chemoprophylaxis. Pre-clinical and clinical studies have demonstrated whole sporozoite vaccine immunogenicity, including humoral and cellular immunity and a range of vaccine efficacy that depends on the pre-exposure of vaccinated individuals. While whole sporozoite vaccines can provide protection against malaria in some cases, more recent studies in malaria-endemic regions demonstrate the need for improvements. Moreover, challenges remain in manufacturing large quantities of sporozoites for vaccine commercialization. A promising solution to the whole sporozoite manufacturing challenge is in vitro culturing methodology, which has been described for several Plasmodium species, including the major disease-causing human malaria parasite, Plasmodium falciparum. Here, we review whole sporozoite vaccine immunogenicity and in vitro culturing platforms for sporozoite production

Correlates of Successful Aging in Racial and Ethnic Minority Women Age 80 Years and Older: Findings from the Women’s Health Initiative

BACKGROUND: Most research has focused on definitions and predictors of successful aging. However, racial/ethnic minorities are often under represented in this research. Given that the U.S. population is aging and becoming more racially diverse, we examined correlates of "successful aging," as defined by physical functioning and overall quality of life (QOL), among racial/ethnic minority women aged 80 years and older in the Women's Health Initiative. METHODS: Participants included 1,924 racial/ethnic minority women (African Americans, Asian/Pacific Islanders, Hispanic/Latinos, and American Indian/Alaskan Natives) 80 years of age and older who are enrolled in the Women's Health Initiative and have physical functioning data after turning 80 years of age. Analysis of covariance was used to examine between and within group differences in physical functioning and selfrated overall QOL for African Americans, Asian/Pacific Islanders, and Hispanic/Latinos. RESULTS: We found no significant differences in physical functioning between racial/ethnic minority groups in adjusted analyses. However, overall QOL was significantly different between racial/ethnic minority groups. Age, recreational physical activity, and overall selfrated health were independent correlates of physical functioning across racial/ethnic minority groups, whereas overall selfrated health was the only consistent correlate of overall QOL across the minority groups for the within minority group comparisons. CONCLUSIONS: Between racial/ethnic minority group differences in physical functioning are largely explained by demographic, psychosocial, behavioral, and health-related variables. We found statistically significant differences in selfrated overall QOL between racial/ethnic minority groups

MiRNA-Related SNPs and Risk of Esophageal Adenocarcinoma and Barrett's Esophagus: Post Genome-Wide Association Analysis in the BEACON Consortium.

Incidence of esophageal adenocarcinoma (EA) has increased substantially in recent decades. Multiple risk factors have been identified for EA and its precursor, Barrett's esophagus (BE), such as reflux, European ancestry, male sex, obesity, and tobacco smoking, and several germline genetic variants were recently associated with disease risk. Using data from the Barrett's and Esophageal Adenocarcinoma Consortium (BEACON) genome-wide association study (GWAS) of 2,515 EA cases, 3,295 BE cases, and 3,207 controls, we examined single nucleotide polymorphisms (SNPs) that potentially affect the biogenesis or biological activity of microRNAs (miRNAs), small non-coding RNAs implicated in post-transcriptional gene regulation, and deregulated in many cancers, including EA. Polymorphisms in three classes of genes were examined for association with risk of EA or BE: miRNA biogenesis genes (157 SNPs, 21 genes); miRNA gene loci (234 SNPs, 210 genes); and miRNA-targeted mRNAs (177 SNPs, 158 genes). Nominal associations (P0.50), and we did not find evidence for interactions between variants analyzed and two risk factors for EA/BE (smoking and obesity). This analysis provides the most extensive assessment to date of miRNA-related SNPs in relation to risk of EA and BE. While common genetic variants within components of the miRNA biogenesis core pathway appear unlikely to modulate susceptibility to EA or BE, further studies may be warranted to examine potential associations between unassessed variants in miRNA genes and targets with disease risk.This work was supported by the National Institutes of Health [R01CA136725 to T.L.V. and D.C.W, T32CA009168 to T.L.V, and K05CA124911 to T.L.V.]. Additional funding sources for individual studies included in the BEACON GWAS, and for BEACON investigators, have been acknowledged previously (16).This is the final version of the article. It first appeared from PLOS via http://dx.doi.org/10.1371/journal.pone.012861

Polymorphisms in Genes of Relevance for Oestrogen and Oxytocin Pathways and Risk of Barrett's Oesophagus and Oesophageal Adenocarcinoma: A Pooled Analysis from the BEACON Consortium.

BACKGROUND: The strong male predominance in oesophageal adenocarcinoma (OAC) and Barrett's oesophagus (BO) continues to puzzle. Hormonal influence, e.g. oestrogen or oxytocin, might contribute. METHODS: This genetic-epidemiological study pooled 14 studies from three continents, Australia, Europe, and North America. Polymorphisms in 3 key genes coding for the oestrogen pathway (receptor alpha (ESR1), receptor beta (ESR2), and aromatase (CYP19A1)), and 3 key genes of the oxytocin pathway (the oxytocin receptor (OXTR), oxytocin protein (OXT), and cyclic ADP ribose hydrolase glycoprotein (CD38)), were analysed using a gene-based approach, versatile gene-based test association study (VEGAS). RESULTS: Among 1508 OAC patients, 2383 BO patients, and 2170 controls, genetic variants within ESR1 were associated with BO in males (p = 0.0058) and an increased risk of OAC and BO combined in males (p = 0.0023). Genetic variants within OXTR were associated with an increased risk of BO in both sexes combined (p = 0.0035) and in males (p = 0.0012). We followed up these suggestive findings in a further smaller data set, but found no replication. There were no significant associations between the other 4 genes studied and risk of OAC, BO, separately on in combination, in males and females combined or in males only. CONCLUSION: Genetic variants in the oestrogen receptor alpha and the oxytocin receptor may be associated with an increased risk of BO or OAC, but replication in other large samples are needed