2,144 research outputs found

    Mating-induced reduction in accessory reproductive organ size in the stalk-eyed fly Cyrtodiopsis dalmanni - art. no. 36

    Get PDF
    Background: Internal reproductive organ size is an important determinant of male reproductive success. While the response of testis length to variation in the intensity of sperm competition is well documented across many taxa, few studies address the importance of testis size in determining other components of male reproductive success ( such as mating frequency) or the significance of size variation in accessory reproductive organs. Accessory gland length, but not testis length, is both phenotypically and genetically correlated with male mating frequency in the stalk-eyed fly Cyrtodiopsis dalmanni. Here we directly manipulate male mating status to investigate the effect of copulation on the size of both the testes and the accessory glands of C. dalmanni.Results: Accessory gland length was positively correlated with male mating frequency. Copulation induced a significant decrease in accessory gland size. The size of the accessory glands then recovered slowly over the next 8 - 48 hours. Neither testis length nor testis area was altered by copulation.Conclusion: These results reveal that the time course of accessory gland recovery corresponds to field observations of mating behaviour and suggest that accessory gland size may limit male mating frequency in C. dalmanni

    No Detectable Fertility Benefit from a Single Additional Mating in Wild Stalk-Eyed Flies

    Get PDF
    Background: Multiple mating by female insects is widespread, and the explanation(s) for repeated mating by females has been the subject of much discussion. Females may profit from mating multiply through direct material benefits that increase their own reproductive output, or indirect genetic benefits that increase offspring fitness. One particular direct benefit that has attracted significant attention is that of fertility assurance, as females often need to mate multiply to achieve high fertility. This hypothesis has never been tested in a wild insect population.Methodology/Principal Findings: Female Malaysian stalk-eyed flies (Teleopsis dalmanni) mate repeatedly during their lifetime, and have been shown to be sperm limited under both laboratory and field conditions. Here we ask whether receiving an additional mating alleviates sperm limitation in wild females. In our experiment one group of females received a single additional mating, while a control group received an interrupted, and therefore unsuccessful, mating. Females that received an additional mating did not lay more fertilised eggs in total, nor did they lay proportionately more fertilised eggs. Female fertility declined significantly through time, demonstrating that females were sperm limited. However, receipt of an additional mating did not significantly alter the rate of this decline.Conclusions/Significance: Our data suggest that the fertility consequences of a single additional mating were small. We discuss this effect (or lack thereof), and suggest that it is likely to be attributed to small ejaculate size, a high proportion of failed copulations, and the presence of X-linked meiotic drive in this species

    Adolescents with Obstructive Sleep Apnea Adhere Poorly to Positive Airway Pressure (PAP), but PAP Users Show Improved Attention and School Performance

    Get PDF
    Background: Obstructive Sleep Apnea (OSA) is associated with medical and neurobehavioral morbidity across the lifespan. Positive airway pressure (PAP) treatment has demonstrated efficacy in treating OSA and has been shown to improve daytime functioning in adults, but treatment adherence can be problematic. There are nearly no published studies examining functional outcomes such as academic functioning in adolescents treated with PAP. This study was conducted as an initial step towards determining whether PAP treatment improves daytime functioning among adolescents with OSA. Methods: Self-reported academic grades, self- and parent-reported academic quality of life, and objectively-measured attention were assessed before and after PAP was clinically initiated in a sample of 13 obese adolescents with OSA, as well as 15 untreated obese Controls without OSA. Based on adherence data, the treated group was divided into PAP Users (n = 6) and Non-Adherent participants (n = 7). Results: Though demographically similar, the three groups significantly differed in how their academic performance and attention scores changed from baseline to follow-up. Non-Adherent participants showed worsening functioning over time, while PAP Users showed stable or improved functioning, similar to controls. Conclusion: Although many adolescents prescribed PAP for OSA are non-adherent to the treatment, those who adhere t

    Health literacy, health status, and healthcare utilization of Taiwanese adults: results from a national survey

    Get PDF
    Abstract Background Low health literacy is considered a worldwide health threat. The purpose of this study is to assess the prevalence and socio-demographic covariates of low health literacy in Taiwanese adults and to investigate the relationships between health literacy and health status and health care utilization. Methods A national survey of 1493 adults was conducted in 2008. Health literacy was measured using the Mandarin Health Literacy Scale. Health status was measured based on self-rated physical and mental health. Health care utilization was measured based on self-reported outpatient clinic visits, emergency room visits, and hospitalizations. Results Approximately thirty percent of adults were found to have low (inadequate or marginal) health literacy. They tended to be older, have fewer years of schooling, lower household income, and reside in less populated areas. Inadequate health literacy was associated with poorer mental health (OR, 0.57; 95% CI, 0.35-0.91). No association was found between health literacy and health care utilization even after adjusting for other covariates. Conclusions Low (inadequate and marginal) health literacy is prevalent in Taiwan. High prevalence of low health literacy is not necessarily indicative of the need for interventions. Systematic efforts to evaluate the impact of low health literacy on health outcomes in other countries would help to illuminate features of health care delivery and financing systems that may mitigate the adverse health effects of low health literacy.http://deepblue.lib.umich.edu/bitstream/2027.42/78252/1/1471-2458-10-614.xmlhttp://deepblue.lib.umich.edu/bitstream/2027.42/78252/2/1471-2458-10-614.pdfPeer Reviewe

    Super-Resolution Dissection of Coordinated Events during Malaria Parasite Invasion of the Human Erythrocyte

    Get PDF
    Erythrocyte invasion by the merozoite is an obligatory stage in Plasmodium parasite infection and essential to malaria disease progression. Attempts to study this process have been hindered by the poor invasion synchrony of merozoites from the only in vitro culture-adapted human malaria parasite, Plasmodium falciparum. Using fluorescence, three-dimensional structured illumination, and immunoelectron microscopy of filtered merozoites, we analyze cellular and molecular events underlying each discrete step of invasion. Monitoring the dynamics of these events revealed that commitment to the process is mediated through merozoite attachment to the erythrocyte, triggering all subsequent invasion events, which then proceed without obvious checkpoints. Instead, coordination of the invasion process involves formation of the merozoite-erythrocyte tight junction, which acts as a nexus for rhoptry secretion, surface-protein shedding, and actomyosin motor activation. The ability to break down each molecular step allows us to propose a comprehensive model for the molecular basis of parasite invasion. © 2011 Elsevier Inc

    The interaction between a sexually transferred steroid hormone and a female protein regulates oogenesis in the malaria mosquito anopheles gambiae

    Get PDF
    Molecular interactions between male and female factors during mating profoundly affect the reproductive behavior and physiology of female insects. In natural populations of the malaria mosquito Anopheles gambiae, blood-fed females direct nutritional resources towards oogenesis only when inseminated. Here we show that the mating-dependent pathway of egg development in these mosquitoes is regulated by the interaction between the steroid hormone 20-hydroxy-ecdysone (20E) transferred by males during copulation and a female Mating-Induced Stimulator of Oogenesis (MISO) protein. RNAi silencing of MISO abolishes the increase in oogenesis caused by mating in blood-fed females, causes a delay in oocyte development, and impairs the function of male-transferred 20E. Co-immunoprecipitation experiments show that MISO and 20E interact in the female reproductive tract. Moreover MISO expression after mating is induced by 20E via the Ecdysone Receptor, demonstrating a close cooperation between the two factors. Male-transferred 20E therefore acts as a mating signal that females translate into an increased investment in egg development via a MISO-dependent pathway. The identification of this male–female reproductive interaction offers novel opportunities for the control of mosquito populations that transmit malaria

    Keywords are missing: Insights from the publication keywords, abstracts and titles of an environment and human health research group

    Get PDF
    This is the final version. Available from SAGE Publications via the DOI in this record. Inequalities within academia – and the research outputs of academic – are a widely acknowledged problem. This results in the reproduction of knowledge gaps within academic praxis. The current study presents a case study from an environment and human health research group, looking at the extent to which the research outputs mirror the wider knowledge gaps in the field. We use systematic review search methods to obtain publications for an environment and health research group since 2010. We use a combination of EndNote and VosViewer to analyse the frequency of key words and concepts in the titles, abstracts and keywords of these publications. We retrieved a total of 950 publications between 2010 and 2022. We find significant gaps with respect to key concepts appearing in the titles, abstracts and keywords of publications. We find that terms such as ‘colonisation’ and ‘racism’ are not mentioned at all. We reflect on the production process of academic research with respect to reproducing blind spots within environment and human health research. We discuss our results in the context of calls to make academic research more inclusive.Natural Environment Research Council (NERC

    Pulling together: keeping track of pedagogy, design and evaluation through the development of scenarios: a case study

    Get PDF
    This case study describes the multipurpose use of scenarios in a large multinational research project (MOBIlearn) whose aims are to design and develop a pedagogically sound mobile learning environment. Maintaining effective communication and design focus in large consortia is a wellknown problem (see Carroll, 2000), and we describe the role of scenarios in addressing this. Scenarios were initially used to simply envision the future system in order to inform design, but as the project progressed, the role of the scenarios grew to encompass (i) relating system design and implementation to pedagogy by providing a common frame of reference for developers and pedagogic experts; (ii) through a process of refinement, defining the evaluation strategy for the user trials; and (iii) allowing us to keep the user at the heart of the development project. Thus, scenarios helped to resolve the difficulty identified by Taylor (2004) of how to bring together the relatively high level issues of pedagogic evaluation and the more technical user-centred system evaluation. The development of a first-aid training scenario is used as an illustrative example

    Conceptualising production, productivity and technology in pharmacy practice: a novel framework for policy, education and research.

    Get PDF
    CONTEXT AND BACKGROUND: People and health systems worldwide face serious challenges due to shifting disease demographics, rising population demands and weaknesses in healthcare provision, including capacity shortages and lack of impact of healthcare services. These multiple challenges, linked with the global push to achieve universal health coverage, have made apparent the importance of investing in workforce development to improve population health and economic well-being. In relation to medicines, health systems face challenges in terms of access to needed medicines, optimising medicines use and reducing risk. In 2017, the International Pharmaceutical Federation (FIP) published global policy on workforce development ('the Nanjing Statements') that describe an envisioned future for professional education and training. The documents make clear that expanding the pharmacy workforce benefits patients, and continually improving education and training produces better clinical outcomes. AIMS AND PURPOSE: The opportunities for harnessing new technologies in pharmacy practice have been relatively ignored. This paper presents a conceptual framework for analysing production methods, productivity and technology in pharmacy practice that differentiates between dispensing and pharmaceutical care services. We outline a framework that may be employed to study the relationship between pharmacy practice and productivity, shaped by educational and technological inputs. METHOD AND RESULTS: The analysis is performed from the point of view of health systems economics. In relation to pharmaceutical care (patient-oriented practice), pharmacists are service providers; however, their primary purpose is not to deliver consultations, but to maximise the quantum of health gain they secure. Our analysis demonstrates that 'technology shock' is clearly beneficial compared with orthodox notions of productivity or incremental gain implementations. Additionally, the whole process of providing professional services using 'pharmaceutical care technologies' is governed by local institutional frames, suggesting that activities may be structured differently in different places and countries. DISCUSSION AND CONCLUSION: Addressing problems with medication use with the development of a pharmaceutical workforce that is sufficient in quantity and competence is a long-term issue. As a result of this analysis, there emerges a challenge about the profession's relationship with existing and emerging technical innovations. Our novel framework is designed to facilitate policy, education and research by providing an analytical approach to service delivery. By using this approach, the profession could develop examples of good practice in both developed and developing countries worldwide
    corecore