Laboratory experimental evolution provides a window into the details of the evolutionary process. To investigate the consequences of long-term adaptation, we evolved 205 S. cerevisiae populations (124 haploid and 81 diploid) for ∼10,000 generations in three environments. We measured the dynamics of fitness changes over time, finding repeatable patterns of declining adaptability. Sequencing revealed that this phenotypic adaptation is coupled with a steady accumulation of mutations, widespread genetic parallelism, and historical contingency. In contrast to long-term evolution in E. coli, we do not observe long-term coexistence or populations with highly elevated mutation rates. We find that evolution in diploid populations involves both fixation of heterozygous mutations and frequent loss-of-heterozygosity events. Together, these results help distinguish aspects of evolutionary dynamics that are likely to be general features of adaptation across many systems from those that are specific to individual organisms and environmental conditions.

The aim of this study was to examine female sex workers’ solicitation of clients using mobile phones and the association between this and condom use with clients. Cross-sectional data were utilised to address the study's aim, drawing on data collected from female sex workers in Calicut, Kerala and Chirala, Andhra Pradesh. Use of mobile phone solicitation was reported by 46.3% (n = 255) of Kerala participants and 78.7% (n = 464) of those in Andhra Pradesh. Kerala participants reporting exclusive solicitation using mobile phones demonstrated 1.67 times higher odds (95% CI: 1.01–2.79) of inconsistent condom use than those reporting non-use of mobile phones for solicitation. However, those reporting exclusive solicitation through mobile phones in Andhra Pradesh reported lower odds of inconsistent condom use (OR: 0.03; 95% CI: 0.01–0.26) than those not using mobile phones for solicitation. Findings indicate that solicitation of clients using mobile phones facilitates or hampers consistency in condom use with clients depending on the context, and how mobile phones are incorporated into solicitation practices. Variations in sex work environments, including economic dependence on sex work or lack thereof may partially account for the different effects found.

Common sub-expression elimination (CSE) serves as a useful optimization technique in the synthesis of arithmetic datapaths described at RTL. However, CSE has a limited potential for optimization when many common sub-expressions are not exposed. Given a suitable transformation of the polynomial system representation, which exposes many common sub-expressions, subsequent CSE can offer a higher degree of optimization. The objective of this paper is to develop algebraic techniques that perform such a transformation, and present a methodology to integrate it with CSE to further enhance the potential for optimization. In our experiments, we show that this integrated approach outperforms conventional methods in deriving areaefficient hardware implementations of polynomial systems. I. IntroductionHigh-level descriptions of arithmetic datapaths that perform polynomial computations over bit-vectors are found in many practical applications, such as in Digital Signal Processing (DSP) for multi-media applications and embedded systems. These polynomial designs are initially specified using behavioural or Register-Transfer-Level (RTL) descriptions, which are subsequently synthesized into hardware using high-level/logic synthesis tools [1]. The growing market for such applications requires sophisticated CAD support for their design, optimization and synthesis.The general area of high-level synthesis has seen extensive research over the years. Various algorithmic techniques have been devised, and CAD tools have been developed that are quite adept at capturing hardware description language (HDL) models and mapping them into control/data-flow graphs (CDFGs), performing scheduling, resource allocation and sharing, binding, retiming, etc., [2]. However, these tools lack the mathematical wherewithal to perform sophisticated algebraic manipulation for arithmetic datapath-intensive designs. Such designs implement a sequence of add, mult type of algebraic computations over bit-vectors; they are generally modeled at RTL or behavioral-level as systems of multi-variate polynomials of finite degree [3] [4]. Hence, there has been increasing interest in exploring the use of algebraic manipulation of polynomial expressions, for RTL synthesis of arithmetic datapaths. Several techniques such as Horner decomposition, factoring with common sub-expression elimination [5], term-rewriting [6], etc., have been proposed. Symbolic computer algebra [3] [4] [7] has also been employed for

Large vertebrates are extremely sensitive to anthropogenic pressure, and their populations are declining fast. The white rhinoceros (Ceratotherium simum) is a paradigmatic case: this African megaherbivore suffered a remarkable population reduction in the last 150 years due to human activities. The two white rhinoceros subspecies, the northern (NWR) and the southern white rhinoceros (SWR), however, underwent opposite fates: the NWR vanished quickly after the onset of the decline, while the SWR recovered after a severe bottleneck. Such demographic events are predicted to have an erosive effect at the genomic level, in connection with the extirpation of diversity, and increased genetic drift and inbreeding. However there is currently little empirical data available that allows us to directly reconstruct the subtleties of such processes in light of distinct demographic histories. Therefore to assess these effects, we generated a whole-genome, temporal dataset consisting of 52 re-sequenced white rhinoceros genomes, that represents both subspecies at two time windows: before and during/after the bottleneck. Our data not only reveals previously unknown population substructure within both subspecies, but allowed us to quantify the genomic erosion undergone by both, with post-bottleneck white rhinoceroses harbouring significantly fewer heterozygous sites, and showing higher inbreeding coefficients than pre-bottleneck individuals. Moreover, the effective population size suffered a decrease of two and three orders of magnitude in the NWR and SWR respectively, due to the recent bottleneck. Our data therefore provides much needed empirical support for theoretical predictions about the genomic consequences of shrinking populations, information that is relevant for understanding the process of population extinction. Furthermore, our findings have the potential to inform management approaches for the conservation of the remaining white rhinoceroses.

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