681 research outputs found

    Radio-telemetric evidence of migration in the gregarious but not the solitary morph of the Mormon cricket (Anabrus simplex : Orthoptera: Tettigoniidae

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    Abstract The Mormon cricket, Anabrus simplex, is one of just a few species of katydids (or bushcrickets, Orthoptera: Tettigoniidae) that, like migratory locusts, appear to have solitary and migratory morphs. Using radio telemetry we studied movements of individuals of two morphs of this flightless species. Individuals within each migratory band had similar rates of movements along similar directional headings whereas solitary individuals moved little and showed little evidence of directionality in movement. Our results also add to other recent radio-telemetry studies showing that flightless insects of 1-2 g in mass can be tracked successfully using these methods

    Cross-linguistic study of vocal pathology: perceptual features of spasmodic dysphonia in French-speaking subjects

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    Clinical characterisation of Spasmodic Dysphonia of the adductor type (SD) in French speakers by Klap and colleagues (1993) appears to differ from that of SD in English. This perceptual analysis aims to describe the phonetic features of French SD. A video of 6 French speakers with SD supplied by Klap and colleagues was analysed for frequency of phonatory breaks, pitch breaks, harshness, creak, breathiness and falsetto voice, rate of production, and quantity of speech output. In contrast to English SD, the French speaking SD patients demonstrated no evidence pitch breaks, but phonatory breaks, harshness and breathiness were prominent features. This verifies the French authors’ (1993) clinical description. These findings suggest that phonetic properties of a specific language may affect the manifestation of pathology in neurogenic voice disorders

    Polymer reptation and nucleosome repositioning

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    We consider how beads can diffuse along a chain that wraps them, without becoming displaced from the chain; our proposed mechanism is analogous to the reptation of "stored length" in more familiar situations of polymer dynamics. The problem arises in the case of globular aggregates of proteins (histones) that are wound by DNA in the chromosomes of plants and animals; these beads (nucleosomes) are multiply wrapped and yet are able to reposition themselves over long distances, while remaining bound by the DNA chain.Comment: 9 pages, including 2 figures, to be published in Phys. Rev. Let

    Do associations support authoritarian rule? Evidence from Algeria, Mozambique, and Vietnam

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    Whether associations help to democratize authoritarian rule or support those in power is a contested issue that so far lacks a cross-regional, comparative perspective. In this article we focus on five types of associations in three post-socialist countries, situated in different world regions, that are governed by authoritarian regimes. We first explore how infrastructural and discursive state power impact such associations and vice versa. We then discuss whether these associations support the development of citizens' collective and individual self-determination and autonomy and/or whether they negate such self-determination and autonomy - a state of affairs that is at the core of authoritarianism. Our analysis addresses decision-making in associations and three specific policy areas. We find that most of the covered associations accept or do not openly reject state/ruling party interference in their internal decision-making processes. Moreover, in most of these associations the self-determination and autonomy of members are restricted, if not negated. With respect to HIV/AIDS policy, associations in Algeria and Vietnam toe the official line, and thus contribute, unlike their counterparts in Mozambique, to negating the self-determination and autonomy of affected people and other social minorities. Looking at enterprise promotion policy, we find that the co-optation of business and professionals’ associations in all three countries effectively limits democratizing impulses. Finally, in all three countries many, but not all, of the interviewed associations support state-propagated norms concerning gender and gender relationships, thus contributing to limiting the self-determination and autonomy of women in the private sphere

    Towards a framework for attention cueing in instructional animations: Guidelines for research and design

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    This paper examines the transferability of successful cueing approaches from text and static visualization research to animations. Theories of visual attention and learning as well as empirical evidence for the instructional effectiveness of attention cueing are reviewed and, based on Mayer’s theory of multimedia learning, a framework was developed for classifying three functions for cueing: (1) selection—cues guide attention to specific locations, (2) organization—cues emphasize structure, and (3) integration—cues explicate relations between and within elements. The framework was used to structure the discussion of studies on cueing in animations. It is concluded that attentional cues may facilitate the selection of information in animations and sometimes improve learning, whereas organizational and relational cueing requires more consideration on how to enhance understanding. Consequently, it is suggested to develop cues that work in animations rather than borrowing effective cues from static representations. Guidelines for future research on attention cueing in animations are presented

    Mating patterns influence vulnerability to the extinction vortex

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    Earth's biodiversity is undergoing mass extinction due to anthropogenic compounding of environmental, demographic and genetic stresses. These different stresses can trap populations within a reinforcing feedback loop known as the extinction vortex, in which synergistic pressures build upon one another through time, driving down population viability. Sexual selection, the widespread evolutionary force arising from competition, choice and reproductive variance within animal mating patterns could have vital consequences for population viability and the extinction vortex: (a) if sexual selection reinforces natural selection to fix ‘good genes’ and purge ‘bad genes’, then mating patterns encouraging competition and choice may help protect populations from extinction; (b) by contrast, if mating patterns create load through evolutionary or ecological conflict, then population viability could be further reduced by sexual selection. We test between these opposing theories using replicate populations of the model insect Tribolium castaneum exposed to over 10 years of experimental evolution under monogamous versus polyandrous mating patterns. After a 95‐generation history of divergence in sexual selection, we compared fitness and extinction of monogamous versus polyandrous populations through an experimental extinction vortex comprising 15 generations of cycling environmental and genetic stresses. Results showed that lineages from monogamous evolutionary backgrounds, with limited opportunities for sexual selection, showed rapid declines in fitness and complete extinction through the vortex. By contrast, fitness of populations from the history of polyandry, with stronger opportunities for sexual selection, declined slowly, with 60% of populations surviving by the study end. The three vortex stresses of (a) nutritional deprivation, (b) thermal stress and (c) genetic bottlenecking had similar impacts on fitness declines and extinction risk, with an overall sigmoid decline in survival through time. We therefore reveal sexual selection as an important force behind lineages facing extinction threats, identifying the relevance of natural mating patterns for conservation management

    The views of general practitioners and practice nurses towards the barriers and facilitators of proactive, internet-based chlamydia screening for reaching young heterosexual men

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    Background: Chlamydia trachomatis is a common bacterial sexually transmitted infection (STI), which disproportionately affects young people under 25 years. Commonly, more women are offered screening than men. This study obtained the views of general practitioners and practice nurses towards Internet-based screening and assessed levels of support for the development of proactive screening targeting young heterosexual men via the Internet. Methods: Semi-structured telephone interviews with 10 general practitioners and 8 practice nurses, across Central Scotland. Topics covered: experience of screening heterosexual men for chlamydia, views on the use of the Internet as a way to reach young men for chlamydia screening, beliefs about the potential barriers and facilitators to Internet-based screening. Transcripts from audio recordings were analysed with Framework Analysis, using QSR NVivo10. Results: Experiences of chlamydia screening were almost exclusively with women, driven by the nature of consultations and ease of raising sexual health issues with female patients; few practice nurses reported seeing men during consultations. All participants spoke in favour of Internet-based screening for young men. Participants reported ease of access and convenience as potential facilitators of an Internet-based approach but anonymity and confidentiality could be potential barriers and facilitators to the success of an Internet approach to screening. Concerns over practical issues as well as those pertaining to gender and socio-cultural issues were raised. Conclusions: Awareness of key barriers and facilitators, such as confidentiality, practicality and socio-cultural influences, will inform the development of an Internet-based approach to screening. However, this approach may have its limits in terms of being able to tackle wider social and cultural barriers, along with shifts in young people's and health professionals' attitudes towards screening. Nevertheless, employing innovative efforts as part of a multi-faceted approach is required to ensure effective interventions reach the policy agenda
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