82 research outputs found

    Host-parasite cophylogeny and rates of evolution in two rodent-louse assemblages

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    Studies of cophylogeny greatly increase understanding of associations between hosts and their parasites. This study uses molecular data to test the hypothesis that members of two rodent families (Geomyidae and Heteromyidae) and their associated lice (Geomydoecus and Fahrenholzia, respectively) show a statistically significant pattern of cophylogeny. Both host groups are generally solitary organisms and both louse groups are obligate ectoparasites, often exhibiting extreme degrees of host specificity. This intimate and potentially long-term association likely has resulted in coevolutionary adaptations and counter adaptations on the part of both symbiotic partners. Phylogenetic analysis of chewing lice (Geomydoecus) reveals two major clades corresponding to the G. coronadoi and G. mexicanus species complexes. These louse complexes are reciprocally monophyletic, and each clade within each complex parasitizes a different species of pocket gopher. Both louse species complexes exhibit a significant pattern of cophylogeny when compared to their hosts. The mitochondrial COI gene of lice of the G. coronadoi complex is evolving approximately 2 -3 times faster than the COI gene of their hosts, whereas the COI gene of lice of the G. mexicanus complex is evolving at roughly the same rate as the same gene of their hosts. Future analyses are necessary to determine why evolutionary rates in these two parasite lineages differ. The phylogenetic analysis of sucking lice (Fahrenholzia) resolves relationships among 11 of the 12 currently recognized species and identifies several possible cryptic species. Although there is conflict among the basal nodes of the host and parasite phylogenies, cophylogenetic analysis reveals significant topological congruence between these lice and their heteromyid hosts. The mitochondrial COI gene of Fahrenholzia lice is evolving roughly 1.6 times faster than the COI gene of their hosts, but additional comparisons of molecular rates are necessary to determine if this rate difference is shared by other groups of sucking lice and their hosts. Results of this study indicate that a combination of tree-based, distance-based, and data-based methods should be used in cophylogeny analyses. The final chapter of this dissertation presents a compilation of mammal-louse associations reveals and offers a preliminary assessment of sucking louse prevalence and abundance on heteromyid rodents

    Bridging Opportunities in Human Health Services

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    The Campus to Community project aims to develop facilitated, in-depth site visits for VCU faculty and staff interested in exploring human health services opportunities in the Richmond community. The site visit experience will provide exposure to various community organizations specializing in human health, essentially creating a “bridge” between VCU’s campus and these facilities. This initiative is intended to motivate employees to action within the Richmond community by enabling them to observe first-hand the services that these organizations provide, learn more about the organizations’ missions, and engage in meaningful interactions with representatives on site. Likewise, it will allow Richmond community organizations to discuss unique needs and opportunities for partnerships with VCU

    Evolutionary history of mammalian sucking lice (Phthiraptera: Anoplura)

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    <p>Abstract</p> <p>Background</p> <p>Sucking lice (Phthiraptera: Anoplura) are obligate, permanent ectoparasites of eutherian mammals, parasitizing members of 12 of the 29 recognized mammalian orders and approximately 20% of all mammalian species. These host specific, blood-sucking insects are morphologically adapted for life on mammals: they are wingless, dorso-ventrally flattened, possess tibio-tarsal claws for clinging to host hair, and have piercing mouthparts for feeding. Although there are more than 540 described species of Anoplura and despite the potential economical and medical implications of sucking louse infestations, this study represents the first attempt to examine higher-level anopluran relationships using molecular data. In this study, we use molecular data to reconstruct the evolutionary history of 65 sucking louse taxa with phylogenetic analyses and compare the results to findings based on morphological data. We also estimate divergence times among anopluran taxa and compare our results to host (mammal) relationships.</p> <p>Results</p> <p>This study represents the first phylogenetic hypothesis of sucking louse relationships using molecular data and we find significant conflict between phylogenies constructed using molecular and morphological data. We also find that multiple families and genera of sucking lice are not monophyletic and that extensive taxonomic revision will be necessary for this group. Based on our divergence dating analyses, sucking lice diversified in the late Cretaceous, approximately 77 Ma, and soon after the Cretaceous-Paleogene boundary (ca. 65 Ma) these lice proliferated rapidly to parasitize multiple mammalian orders and families.</p> <p>Conclusions</p> <p>The diversification time of sucking lice approximately 77 Ma is in agreement with mammalian evolutionary history: all modern mammal orders are hypothesized to have diverged by 75 Ma thus providing suitable habitat for the colonization and radiation of sucking lice. Despite the concordant timing of diversification events early in the association between anoplurans and mammals, there is substantial conflict between the host and parasite phylogenies. This conflict is likely the result of a complex history of host switching and extinction events that occurred throughout the evolutionary association between sucking lice and their mammalian hosts. It is unlikely that there are any ectoparasite groups (including lice) that tracked the early and rapid radiation of eutherian mammals.</p

    Temporal and spatial dynamics of competitive parapatry in chewing lice

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    We synthesize observations from 1979 to 2016 of a contact zone involving two subspecies of pocket gophers (Thomomys bottae connectens and T. b. opulentus) and their respective chewing lice (Geomydoecus aurei and G. centralis) along the Rio Grande Valley in New Mexico, U.S.A., to test predictions about the dynamics of the zone. Historically, the natural flood cycle of the Rio Grande prevented contact between the two subspecies of pocket gophers. Flood control measures completed in the 1930s permitted contact, thus establishing the hybrid zone between the pocket gophers and the contact zone between their lice (without hybridization). Since that time, the pocket gopher hybrid zone has stabilized, whereas the northern chewing louse species has replaced the southern louse species at a consistent rate of similar to 150 m/year. The 0.2-0.8 width of the replacement zone has remained constant, reflecting the constant rate of chewing louse species turnover on a single gopher and within a local pocket gopher population. In contrast, the full width of the replacement zone (northernmost G. centralis to southernmost G. aurei) has increased annually. By employing a variety of metrics of the species replacement zone, we are better able to understand the dynamics of interactions between and among the chewing lice and their pocket gopher hosts. This research provides an opportunity to observe active species replacement and resulting distributional shifts in a parasitic organism in its natural setting

    Review of endemic Sulawesi squirrels.

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    260 p. : ill. (some col.), maps ; 26 cm. "Issued June 11, 2010." Includes bibliographical references (p. 246-255).Analyses of fur color patterns, morphometric data derived from external, cranial, and dental dimensions, and distributions of collection sites for voucher specimens form the basis for a taxonomic revision of Sulawesi’s endemic squirrel fauna. Eight species of tree squirrels in Rubrisciurus and Prosciurillus and two species of ground squirrels in Hyosciurus are recognized. All are diurnal and inhabit primary forest formations. Diet consists of fruit, nuts, seeds, and arthropods. Rubrisciurus rubriventer, the largest in body size, forages on the ground and in the lower canopy layer, is found throughout Sulawesi where primary forest persists, and occurs through an altitudinal range embracing tropical lowland evergreen and lower montane rain forests; it is absent from upper montane rain forest. Five species of arboreal squirrels comprise the Prosciurillus leucomus group, a cluster of species occupying the upper forest canopy: P. leucomus, known only from lowland and montane habitats in the northern peninsula and one offshore island; P. alstoni, recorded from lowland tropical evergreen rain forest in the eastern section of Sulawesi’s central core, the east-central and southeastern arms, and two southeastern islands; P. weberi, represented by a few specimens from the coastal lowlands of the southern core of Sulawesi; P. topapuensis, endemic to the western mountain block in Sulawesi’s central core and occurring along an altitudinal gradient from lowland evergreen rain forest to upper montane rain forest; and P. rosenbergii, the only species of squirrel collected on islands in the Sangihe Archipelago north of the northeastern tip of the northern peninsula. The Prosciurillus murinus group contains two species of small body size: P. murinus, found throughout Sulawesi and in all forest formations, from the coastal lowlands to mountaintops, and a forager in the lower canopy layers; and P. abstrusus, known only from montane forest habitats on Pegunungan Mekongga in the southeastern peninsula. Of two species of ground squirrels, Hyosciurus heinrichi occupies montane forest habitats in the western mountain block of Sulawesi’s central core. It is altitudinally parapatric to H. ileile, which inhabits lowland evergreen and lower montane rain forests in the western mountain block and northeastern lowlands of central Sulawesi, and montane forest on the northern peninsula. A slightly revised classification of Sciuridae is provided in which a new tribe, Exilisciurini, is proposed for the Bornean and Philippine Exilisciurus. Previously published results of morphological and molecular analyses point to Rubrisciurus, Prosciurillus, and Hyosciurus as a monophyletic cluster, the Hyosciurina, nested within a larger clade, the Nannosciurini, which along with Exilisciurini n. tribe and Funambulini, comprise the Nannosciurinae, one of the three subfamilies constituting Sciuridae, and one that contains most of the Indomalayan genera. The present diversity of species endemic to Sulawesi was derived from an ancient lineage that crossed a sea barrier from the Sunda Shelf to Sulawesi during the late Miocene. Eight new species of hoplopleurid sucking lice ‪(‬Insecta, Anoplura‪)‬ are described as parasitizing 8 of the 10 species of squirrels endemic to Sulawesi: Hoplopleura rubrisciuri from Rubrisciurus rubriventer, Hoplopleura leucomus from Prosciurillus leucomus, Hoplopleura alstoni from Prosciurillus alstoni, Hoplopleura topapuensis from Prosciurillus topapuensis, Hoplopleura murinus from Prosciurillus murinus, Hoplopleura abstrusus from Prosciurillus abstrusus, Hoplopleura heinrichi from Hyosciurus heinrichi, and Hoplopleura ileile from Hyosciurus ileile. Examples of Prosciurillus weberi and P. rosenbergii were surveyed but no lice were recovered. A phylogenetic analysis based on cladistic principles for six species of Sulawesian squirrel lice for which both sexes were available is presented and the results discussed with respect to host relationships. These new data are incorporated into a discussion covering zoogeography of global sciurid-sucking louse associations, emphasizing the Indomalayan squirrel fauna. Globally, members of 11 genera of Anoplura parasitize sciurids, a figure far exceeding the number of anopluran genera associated with any other mammalian family. Nine of these ‪(‬the enderleinellids, Atopophthirus, Enderleinellus, Microphthirus, Phthirunculus, and Werneckia; the hoplopleurid, Paradoxophthirus; and the polyplacids, Johnsonpthirus, Linognathoides, and Neohaematopinus‪)‬ are primary parasites of sciurids. The remaining two ‪(‬the hoplopleurid Hoplopleura, and the polyplacid Polyplax‪)‬ include representatives that are acquired ‪(‬secondary‪)‬ parasites of sciurids--the majority of species in these two louse genera parasitize other groups of mammals but a small number of species have transferred to squirrel hosts. Sciurid hosts and geographic distributions of these 11 anopluran genera are discussed. Historically, representatives of Hoplopleura colonized different sciurid hosts on several separate occasions with one known species on a North American tree squirrel ‪(‬Sciurus‪)‬, two described species on North American flying squirrels ‪(‬Glaucomys‪)‬, two species parasitizing North American species of chipmunks ‪(‬Tamias and Eutamias‪)‬, 14 described species from Indomalayan nannosciurine squirrels ‪(‬Callosciurus, Tamiops, Rubrisciurus, Prosciurillus, Hyosciurus, and Funambulus‪)‬, and one species parasitizing a Chinese xerine ground squirrel ‪(‬Sciurotamias‪)‬. The zoogeography of the seven sciurid-infesting louse genera known from Southeast Asia is discussed using data from nine different countries or regions ‪(‬China, Taiwan, Thailand, peninsular Malaysia, Sumatra, Java, Borneo, the Philippines, and Sulawesi‪)‬. A reduction in the number of sciuirid-infesting anopluran genera and species is apparent from mainland northern/western regions to insular southern/eastern regions with members of seven genera and 23 species described from China but only one genus and eight species from Sulawesi. The absence of known species of Hoplopleura from Bornean and Javanese squirrels suggests that such a fauna may await discovery on one or both of these islands. Six of the eight species of Hoplopleura found parasitizing species of endemic Sulawesi squirrels were recovered as a monophyletic clade from a phylogenetic analysis employing anatomical structures associated with male and female lice. ‪(‬Two species of Sulawesi Hoplopleura are based on females and nymphs only and were not incorporated into the analysis.‪)‬ The monophyletic cluster formed by the Sulawesian squirrel lice joined with the monophyletic assemblage containing the three Sulawesi squirrel genera--Rubrisciurus, Prosciurillus, and Hyosciurus--suggest that the ancestral squirrel lineage that arrived in Sulawesi during the late Miocene may have been carrying its unique Hoplopleura parasite

    A meta-analytic review of stand-alone interventions to improve body image

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    Objective Numerous stand-alone interventions to improve body image have been developed. The present review used meta-analysis to estimate the effectiveness of such interventions, and to identify the specific change techniques that lead to improvement in body image. Methods The inclusion criteria were that (a) the intervention was stand-alone (i.e., solely focused on improving body image), (b) a control group was used, (c) participants were randomly assigned to conditions, and (d) at least one pretest and one posttest measure of body image was taken. Effect sizes were meta-analysed and moderator analyses were conducted. A taxonomy of 48 change techniques used in interventions targeted at body image was developed; all interventions were coded using this taxonomy. Results The literature search identified 62 tests of interventions (N = 3,846). Interventions produced a small-to-medium improvement in body image (d+ = 0.38), a small-to-medium reduction in beauty ideal internalisation (d+ = -0.37), and a large reduction in social comparison tendencies (d+ = -0.72). However, the effect size for body image was inflated by bias both within and across studies, and was reliable but of small magnitude once corrections for bias were applied. Effect sizes for the other outcomes were no longer reliable once corrections for bias were applied. Several features of the sample, intervention, and methodology moderated intervention effects. Twelve change techniques were associated with improvements in body image, and three techniques were contra-indicated. Conclusions The findings show that interventions engender only small improvements in body image, and underline the need for large-scale, high-quality trials in this area. The review identifies effective techniques that could be deployed in future interventions

    Palaeoclimatic events, dispersal and migratory losses along the Afro-European axis as drivers of biogeographic distribution in Sylvia warblers

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    <p>Abstract</p> <p>Background</p> <p>The Old World warbler genus <it>Sylvia </it>has been used extensively as a model system in a variety of ecological, genetic, and morphological studies. The genus is comprised of about 25 species, and 70% of these species have distributions at or near the Mediterranean Sea. This distribution pattern suggests a possible role for the Messinian Salinity Crisis (from 5.96-5.33 Ma) as a driving force in lineage diversification. Other species distributions suggest that Late Miocene to Pliocene Afro-tropical forest dynamics have also been important in the evolution of <it>Sylvia </it>lineages. Using a molecular phylogenetic hypothesis and other methods, we seek to develop a biogeographic hypothesis for <it>Sylvia </it>and to explicitly assess the roles of these climate-driven events.</p> <p>Results</p> <p>We present the first strongly supported molecular phylogeny for <it>Sylvia</it>. With one exception, species fall into one of three strongly supported clades: one small clade of species distributed mainly in Africa and Europe, one large clade of species distributed mainly in Africa and Asia, and another large clade with primarily a circum-Mediterranean distribution. Asia is reconstructed as the ancestral area for <it>Sylvia</it>. Long-distance migration is reconstructed as the ancestral character state for the genus, and sedentary behavior subsequently evolved seven times.</p> <p>Conclusion</p> <p>Molecular clock calibration suggests that <it>Sylvia </it>arose in the early Miocene and diverged into three main clades by 12.6 Ma. Divergence estimates indicate that the Messinian Salinity Crisis had a minor impact on <it>Sylvia</it>. Instead, over-water dispersals, repeated loss of long-distance migration, and palaeo-climatic events in Africa played primary roles in <it>Sylvia </it>divergence and distribution.</p

    Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

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    Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10&nbsp;years; 78.2% included were male with a median age of 37&nbsp;years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020
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