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Networks of coupled parametric resonators (parametrons) hold promise for parallel computing architectures. En route to realizing complex networks, we report an experimental and theoretical analysis of two coupled parametrons. In contrast to previous studies, we explore the case of strong bilinear coupling between the parametrons, as well as the role of detuning. We show that the system can still operate as an Ising machine in this regime, even though careful calibration is necessary to ensure that the correct solution space is available. Apart from the formation of split normal modes, new states of mixed symmetry are generated. Furthermore, we predict that systems with N>2 parametrons will undergo multiple phase transitions before arriving at a regime that can be equivalent to the Ising problem.

BACKGROUND:Given the great efforts put into the strategic objective of reducing the proportion of HIV-infected patients that are undiagnosed, the aim of the present study was to review the temporal trends between 1997 and 2016 for median estimates of infection duration and median CD4 count at diagnosis for the main patient origins in French Guiana. METHODS:CD4 cell count at HIV sero-conversion and square root of CD4 cell decline were obtained using the CD4 decline in a cohort of HIV-infected persons in the UK, fitting random effect (slope and intercept) multilevel linear regression models. Multivariate analysis used robust regression for modeling the delay between estimated HIV seroconversion and diagnosis and quantile regression for CD4 at HIV diagnosis. RESULTS:The median interval between the estimated HIV seroconversion and HIV diagnosis was 8 years for patients fromBrazil, 4.5 years for those from Haiti, 6.6 years for those from Suriname, 3.3 years for patients from Guyana, and 3.1 years for French patients. A simple robust regression model with French patients as reference group adjusting for sex and age at the time of diagnosis showed that the interval was significantly longer for Brazilian (β = +3.7 years, P = 0.001), Surinamese (β = +4.2 years, P

Here we report new distributional data for Adenomera heyeri, a recently described species of the lowlands of the Guiana Shield. We compiled available and new occurrence data as well as the absence of records from field surveys that were undertaken in the Guiana Shield in order to evaluate the actual range of the species. We confirm that A. heyeri is potentially distributed over most forested part of the northern Guiana Shield lowlands. The pattern of distribution also reveals valuable information on the ecology of the species.

Amphibians are rapidly vanishing. At the same time, it is most likely that the number of amphibian species is highly underestimated. Recent DNA barcoding work has attempted to define a threshold between intra- and inter-specific genetic distances to help identify candidate species. In groups with high extinction rates and poorly known species boundaries, like amphibians, such tools may provide a way to rapidly evaluate species richness.Here we analyse published and new 16S rDNA sequences from 60 frog species of Amazonia-Guianas to obtain a minimum estimate of the number of undescribed species in this region. We combined isolation by distance, phylogenetic analyses, and comparison of molecular distances to evaluate threshold values for the identification of candidate species among these frogs.In most cases, geographically distant populations belong to genetically highly distinct lineages that could be considered as candidate new species. This was not universal among the taxa studied and thus widespread species of Neotropical frogs really do exist, contrary to previous assumptions. Moreover, the many instances of paraphyly and the wide overlap between distributions of inter- and intra-specific distances reinforce the hypothesis that many cryptic species remain to be described. In our data set, pairwise genetic distances below 0.02 are strongly correlated with geographical distances. This correlation remains statistically significant until genetic distance is 0.05, with no such relation thereafter. This suggests that for higher distances allopatric and sympatric cryptic species prevail. Based on our analyses, we propose a more inclusive pairwise genetic distance of 0.03 between taxa to target lineages that could correspond to candidate species.Using this approach, we identify 129 candidate species, two-fold greater than the 60 species included in the current study. This leads to estimates of around 170 to 460 frog taxa unrecognized in Amazonia-Guianas.As a consequence the global amphibian decline detected especially in the Neotropics may be worse than realised.

Thanks to impulses from the humanities and the natural sciences, the profession of art conservation and restoration has emancipated itself over the past century from its origins as an artisan's craft and established itself as a discipline in its own right. Preserving art and cultural monuments has ceased to refer only to preserving mere substance. Instead, through these activities, signs and traces of age have for the first time become quite consciously an integral part of an independent, completely new form of value for an object–the value of patina or simply 'the value of age'. Central to this process was the idea of 'reversibility', a concept employed by experts and laypersons alike as the ultima ratio for preserving an artwork effectively and without damage for future generations utilizing suitable methods and materials. In daily practice, reversibility has proven to be the ideal rather than the reality. With the realization that any intervention into the substance of an artwork is irreversible, the term 'retreatability' began to be developed in the 1980s. The intention here follows the line of reasoning that restoration measures on an artwork may no longer be reversible once carried out, but further treatment should be neither hampered nor rendered impossible. However, the contradiction between intervention and preservation is in effect insurmountable because not undertaking an intervention is a decision linked to a specific time and puts a further historical stamp on a monument or artwork. This means that conservation/restoration itself becomes a new factor in the historical change an artwork undergoes.

CD8+ T lymphocytes have the potential ability to inhibit human immunodeficiency virus (HIV) replication, by secreting soluble(s) factor(s) known as CD8+ T lymphocyte antiviral factor (CAF). A panel of CD8+ and CD4+ T cell clones from HIV1-infected and uninfected donors were generated to better define the phenotype of CAF-producing cells. We first verified that the different CD4+ T cell subsets (Th0, Th1, and Th2) were productively infected by X4 and R5 virus strains. X4 viral replication in CD4+ T cells was controlled by the three CD8+ T cell subsets (Tc0, Tc1, and Tc2); however, the frequency of Tc clones controlling R5 strain was much lower with a dramatic absence of this activity among Tc clones from uninfected donor. Finally, capacity to control viral replication showed an heterogeneity: some clones could control both virus strains, some controlled only the X4 virus, whereas the majority exerted no suppressive activity. [ABSTRACT FROM AUTHOR]

This paper presents a case study of the key decisions made in the design of Orbit, a child sexual abuse prevention computer game targeted at school students between 8 and 10 years of age. Key decisions include providing supported delivery for the target age group, featuring adults in the program, not over-sanitising game content, having a focus on building healthy self-concept of players, making the game engaging and relatable for all players and evaluating the program. This case study has implications for the design of Serious Games more generally, including that research should underpin game design decisions, game designers should consider ways of bridging the game to real life, the learning that arises from the game should go beyond rote-learning, designers should consider how the player can make the game-world their own and comprehensive evaluations of Serious Games should be undertaken.