2,796 research outputs found

    Spatial and Temporal Relationships Between Forest Bird Declines and Prevalence of the Hemlock Woolly Adelgid in the Northeastern United States

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    The eastern hemlock (Tsuga canadensis) is a vital foundation tree species throughout the eastern United States, providing essential structural diversity and habitat for more than 120 different animal species. Within the past few decades, T. canadensis has undergone significant declines that are largely associated with the hemlock woolly adelgid (HWA; Adelges tsugae), an exotic, aphid-like insect native to East Asia. From the 1970s to present day, the HWA has spread throughout southern New England, large portions of the Mid-Atlantic region, and parts of Tennessee and the Carolinas. Research has shown that loss of the eastern hemlock is drastically altering forest community structures, potentially impacting a wide variety of forest fauna, including avian populations strongly associated with hemlock forests. Here we present research investigating the correlation between HWA prevalence and recent declines of hemlock-associated forest birds in the Eastern US. We analyzed bird population trends data from the North American Breeding Bird Survey (BBS), US Forest Service HWA data, and land cover data to analyze the population trends of hemlock-associated and forest generalist species in association with the arrival of HWA, taking hemlock density into account. We found a significant correlation between the timing of HWA arrival and declines of conifer forest specialist birds. The Black-throated Green Warbler and the Blue-headed Vireo exhibited significant decline along survey routes after HWA arrival. Populations of some forest generalists (Tufted Titmouse, White-Breasted Nuthatch) were unaffected and continued to increase linearly, while others (Red-Eyed Vireo, Ovenbird) showed minor decrease in population

    The Indigenous digital divide: COVID-19 and its impacts on educational delivery to First Nation university students

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    The global COVID 19 pandemic highlighted that the delivery of online education inadvertently disadvantaged Indigenous Australian university students. This situation was particularly critical for Indigenous students from rural and remote locations. Australian universities increased the use of digital technologies to engage, support and teach due to students’ inability to access campuses. This presented universities with challenges in supporting Indigenous students living in and returning to non-urban settings. Often not recognised is the need for better strategies and plans for Indigenous students returning to their rural or remote community to continue their studies due to COVID. These communities often lack suitable infrastructure that would allow access to pedagogical and learning support opportunities. This paper explores how the business decision made by Australian universities to increase reliance on teaching online during COVID impacted the education of Indigenous students. This paper will then canvas ways this ongoing dilemma can be addressed by considering risks, measuring and monitoring performance to guide transformation, including universities’ more inclusive and respectful use of digital technologies involving First Nations people and culture

    Population Dynamics of Long-tailed Ducks Breeding on the Yukon-Kuskokwim Delta, Alaska

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    Population estimates for long-tailed ducks in North America have declined by nearly 50% over the past 30 years. Life history and population dynamics of this species are difficult to ascertain, because the birds nest at low densities across a broad range of habitat types. Between 1991 and 2004, we collected information on productivity and survival of long-tailed ducks at three locations on the Yukon-Kuskokwim Delta. Clutch size averaged 7.1 eggs, and nesting success averaged 30%. Duckling survival to 30 days old averaged 10% but was highly variable among years, ranging from 0% to 25%. Apparent annual survival of adult females based on mark-recapture of nesting females was estimated at 74%. We combined these estimates of survival and productivity into a matrix-based population model, which predicted an annual population decline of 19%. Elasticities indicated that population growth rate (?) was most sensitive to changes in adult female survival. Further, the relatively high sensitivity of ? to duckling survival suggests that low duckling survival may be a bottleneck to productivity in some years. These data represent the first attempt to synthesize a population model for this species. Although our analyses were hampered by the small sample sizes inherent in studying a dispersed nesting species, our model provides a basis for management actions and can be enhanced as additional data become available.Les estimations de populations d’hareldes kakawis en AmĂ©rique du Nord ont chutĂ© de prĂšs de 50 pour cent ces 30 derniĂšres annĂ©es. Le cycle biologique et la dynamique des populations de cette espĂšce sont difficiles Ă  Ă©tablir car ces oiseaux nichent moyennant de faibles densitĂ©s dans une vaste gamme d’habitats. De 1991 Ă  2004, nous avons recueilli des donnĂ©es sur la productivitĂ© et la survie des hareldes kakawis Ă  trois emplacements du delta Yukon-Kuskokwim. Les couvĂ©es atteignaient 7,1 oeufs en moyenne, tandis que le succĂšs de reproduction s’établissait gĂ©nĂ©ralement Ă  30 pour cent. En moyenne, 10 pour cent des jeunes canards survivaient jusqu’à l’ñge de 30 jours, mais ce taux variait beaucoup d’une annĂ©e Ă  l’autre, allant de 0 pour cent Ă  25 pour cent. Annuellement, d’aprĂšs la mĂ©thode par marquage et recapture des femelles nidificatrices, la survie apparente des femelles adultes Ă©tait Ă©valuĂ©e Ă  74 pour cent. Nous avons combinĂ© ces estimations de survie et de productivitĂ© dans un modĂšle de population matriciel, ce qui a permis de prĂ©dire un dĂ©clin de population annuel de 19 pour cent. Selon les Ă©lasticitĂ©s, le taux de croissance de la population (?) Ă©tait plus sensible aux changements dans le cas de la survie des femelles adultes. Par ailleurs, la sensibilitĂ© relativement Ă©levĂ©e du ? par rapport Ă  la survie des jeunes canards laisse croire que le faible taux de survie des jeunes canards pourrait prĂ©senter une embĂ»che en matiĂšre de productivitĂ© d’ici quelques annĂ©es. Ces donnĂ©es reprĂ©sentent la premiĂšre tentative de synthĂšse d’un modĂšle de population pour cette espĂšce. Bien que nos analyses aient Ă©tĂ© gĂȘnĂ©es par la petite taille des Ă©chantillons inhĂ©rente Ă  l’étude d’espĂšces de nidification dispersĂ©es, notre modĂšle fournit un fondement permettant d’aboutir Ă  des mesures de gestion en plus de prĂ©senter la possibilitĂ© d’ĂȘtre amĂ©liorĂ© au fur et Ă  mesure que des donnĂ©es supplĂ©mentaires sont disponibles

    Dental Caries in Children with Sickle Cell Disease and Its Association with the Use of Hydroxyurea and Penicillin Prophylaxis in Dar Es Salaam

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    Purpose. This comparative study sets out to report dental caries status among individuals with Sickle Cell Disease (HbSS) against those with sickle cell trait (HbSA) and those without the disease (HbAA) as controls. The study further assessed the impact of penicillin chemoprophylaxis and hydroxyurea use on dental caries among Sickle Cell Disease participants. Methods. This was a comparative cross-sectional study in which 93 children aged 30 to 60 months were recruited. There were 60 participating children who had SCD (HbSS), 17 with SCD trait (HbAS) and 16 were without SCD or SC trait (HbAA). A questionnaire was used to record sociodemographic details including mean age in months and sex and on haemoglobin genotype for all the participants. Specifically, for the participants with HbSS, information on their whether they are taking hydroxyurea (HU), and penicillin chemoprophylaxis was recorded. To assess the prevalence of dental caries, clinical examination of all primary maxillary and mandibular teeth to determine the presence or absence of dental caries lesions was also recorded. Results. A total of 1197 teeth from 93 children were examined, whereby, 45 (2.4%) of them had dental caries. The participating children with HbAA genotype (6.6%, N=21) had more dental caries than their HbSS counterparts (2.0%, N=24), while none of the participants with HbAS exhibited dental caries. Among the participants with HbSS, males and those who use HU were 3.79 and 3.07 times more likely to have dental caries than their counterparts, female and non-users of HU, respectively. Conclusion. Dental caries was observed to be low among participants with HbSS when compared to those with HbAA. More research utilizing more robust methodologies is recommended

    Low intensity shockwave treatment modulates macrophage functions beneficial to healing chronic wounds

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    Acknowledgments: We acknowledge the University of Aberdeen Microscopy and Histology Facility and the qPCR facility for use of facilities and advice. We acknowledge Ehab Husain for scoring the patient wound biopsies. Funding: This research was funded by NHS Grampian Endowments, grant number 17/004 and by personal funding from JSH.Peer reviewedPublisher PD
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