Impact of community-based interventions on condom use in the Tłįchǫ region of Northwest Territories, Canada

<p>Abstract</p> <p>Background</p> <p>Since 2005, the Tłįchǫ Community Services Agency (TCSA) in Canada's Northwest Territories (NT) has addressed rising rates of sexually transmitted infections (STI). In 2009, STI rates in the NT were ten times higher than the national rate and Tłįchǫ regional rates were nearly four times that of the NT – 91 cases per 1000 people. We describe a social audit process that assessed the impact of an evidence-based community-led intervention.</p> <p>Methods</p> <p>A baseline survey of sexual health knowledge, attitudes and behaviours in 2006/07 provided evidence for a Community Action Research Team (CART) to develop and to put in place culturally appropriate interventions in the Tłįchǫ region. A follow-up study in 2010 sought to assess the impact of CART activities on condom use and underlying conscious knowledge, attitudes, subjective norms, intention to change, sense of agency and discussions related to condom use and STI risks. We report the contrasts using Odds Ratios (OR) and 95% confidence intervals (CI).</p> <p>Results</p> <p>One in every three follow-up respondents (315/808) participated in at least one CART activity. Participation in highly ranked interventions was associated with increased condom use during the last sexual encounter (OR 1.45, 95%CI 1.07-1.98). Those exposed to three or more activities were more likely to talk openly about condoms (OR 2.08, 95%CI 1.41-3.28), but were also less likely to be monogamous (OR 0.49, 95%CI 0.29-0.90).</p> <p>Conclusions</p> <p>The measurable impact on condom use indicates a strong beginning for the Tłįchǫ community intervention programmes. The interventions also seem to generate increased discussion, often a precursor to action. The Tłįchǫ can use the evidence to improve and refocus their programming, increase knowledge and continue to improve safe condom use practices.</p

Fine-Tuning and the Stability of Recurrent Neural Networks

A central criticism of standard theoretical approaches to constructing stable, recurrent model networks is that the synaptic connection weights need to be finely-tuned. This criticism is severe because proposed rules for learning these weights have been shown to have various limitations to their biological plausibility. Hence it is unlikely that such rules are used to continuously fine-tune the network in vivo. We describe a learning rule that is able to tune synaptic weights in a biologically plausible manner. We demonstrate and test this rule in the context of the oculomotor integrator, showing that only known neural signals are needed to tune the weights. We demonstrate that the rule appropriately accounts for a wide variety of experimental results, and is robust under several kinds of perturbation. Furthermore, we show that the rule is able to achieve stability as good as or better than that provided by the linearly optimal weights often used in recurrent models of the integrator. Finally, we discuss how this rule can be generalized to tune a wide variety of recurrent attractor networks, such as those found in head direction and path integration systems, suggesting that it may be used to tune a wide variety of stable neural systems

Two new species of Odontostilbe historically hidden under O. microcephala (Characiformes: Cheirodontinae)

Specimens historically identified as Odontostilbe microcephala from the upper rio Paraná and Andean piedmont tributaries of the río Paraguay are reviewed and split in three species. We found that the distribution of O. microcephala is restricted to the Andean slope of the río Paraguay basin. The species is distinguished from congeners with subterminal mouth by the elongate body, usually 10-12 gill rakers on upper branch and smaller horizontal orbital diameter (24.6-32.8 % HL, mean 28.7%). Specimens from upper rio Paraná constitute two new species, diagnosed from other Cheirodontinae by the presence of mesopterygoid teeth, grouped on median portion and forming a continuous row. The new species are distinguished from each other by having premaxillary teeth with five cusps vs. nine cusps and by the number of lamellae in left and right sides of central median raphe of olfactory rosette with 20-21 vs. 11-12.Espécimes historicamente identificados com Odontostilbe microcephala do rio Paraná e tributários do río Paraguay, foram revisados e separados em três espécies. A distribuição de O. microcephala é restrita ao sopé andino da bacia do río Paraguay. A espécie é distinta das congêneres com boca subterminal pela forma alongada, geralmente 10-12 rastros branquiais no ramo superior e menor diâmetro horizontal da órbita (24,6-32,8 % CC, média 28,7%). Espécimes do alto rio Paraná constituem duas espécies novas diagnosticadas de outros Cheirodontinae pela presença de dentes no mesopterigoide, agrupados em sua porção média e formando uma fileira continua. As novas espécies distinguem-se por ter dentes premaxilares com cinco cúspides vs. nove cúspides e pelo número de lamelas nos lados esquerdo e direito da rafe central da roseta olfativa com 20-21 vs. 11-12

Habitat simplification increases the impact of a freshwater invasive fish

Biodiversity continues to decline at a range of spatial scales and there is an urgent requirement to understand how multiple drivers interact in causing such declines. Further, we require methodologies that can facilitate predictions of the effects of such drivers in the future. Habitat degradation and biological invasions are two of the most important threats to biodiversity and here we investigate their combined effects, both in terms of understanding and predicting impacts on native species. The predatory largemouth bass Micropterus salmoides is one of the World’s Worst Invaders, causing declines in native prey species, and its introduction often coincides with habitat simplification. We investigated the predatory functional response, as a measure of ecological impact, of juvenile largemouth bass in artificial vegetation over a range of habitat complexities (high, intermediate, low and zero). Prey, the female guppy Poecilia reticulata, were representative of native fish. As habitats became less complex, significantly more prey were consumed, since, even although attack rates declined, reduced handling times resulted in higher maximum feeding rates by bass. At all levels of habitat complexity, bass exhibited potentially population de-stabilising Type II functional responses, with no emergence of more stabilising Type III functional responses as often occurs in predator-prey relationships in complex habitats. Thus, habitat degradation and simplification potentially exacerbate the impact of this invasive species, but even highly complex habitats may ultimately not protect native species. The utilisation of functional responses under varying environmental contexts provides a method for the understanding and prediction of invasive species impacts.National Research Foundation. South Afric