163 research outputs found
From presence to consciousness through virtual reality
Immersive virtual environments can break the deep, everyday connection between where our senses tell us we are and where we are actually located and whom we are with. The concept of 'presence' refers to the phenomenon of behaving and feeling as if we are in the virtual world created by computer displays. In this article, we argue that presence is worthy of study by neuroscientists, and that it might aid the study of perception and consciousness
Rectal Transmission of Transmitted/Founder HIV-1 Is Efficiently Prevented by Topical 1% Tenofovir in BLT Humanized Mice
Rectal microbicides are being developed to prevent new HIV infections in both men and women. We focused our in vivo preclinical efficacy study on rectally-applied tenofovir. BLT humanized mice (n = 43) were rectally inoculated with either the primary isolate HIV-1(JRCSF) or the MSM-derived transmitted/founder (T/F) virus HIV-1(THRO) within 30 minutes following treatment with topical 1% tenofovir or vehicle. Under our experimental conditions, in the absence of drug treatment we observed 50% and 60% rectal transmission by HIV-1(JRCSF) and HIV-1(THRO), respectively. Topical tenofovir reduced rectal transmission to 8% (1/12; log rank p = 0.03) for HIV-1(JRCSF) and 0% (0/6; log rank p = 0.02) for HIV-1(THRO). This is the first demonstration that any human T/F HIV-1 rectally infects humanized mice and that transmission of the T/F virus can be efficiently blocked by rectally applied 1% tenofovir. These results obtained in BLT mice, along with recent ex vivo, Phase 1 trial and non-human primate reports, provide a critically important step forward in the development of tenofovir-based rectal microbicides
Psychosocial implications of tubal ligation in a rural health district: A phenomenological study
<p>Abstract</p> <p>Background</p> <p>Tubal ligation is the most popular family planning method worldwide. While its benefits, such as effectiveness in protecting against pregnancies, minimal need for long-term follow-up and low side-effects profile are well documented, it has many reported complications. However, to date, these complications have not been described by residents in Congo. Therefore, the study aimed at exploring the experience of women who had undergone tubal ligation, focusing on perceptions of physical, psychological and contextual experiences of participants.</p> <p>Methods</p> <p>This qualitative study used a semi-structured questionnaire in a phenomenological paradigm to collect data. Fifteen participants were purposefully selected among sterilized women who had a ligation procedure performed, were aged between 30 and 40 years, and were living within the catchment area of the district hospital. Data were collected by two registered nurses, tape-recorded, and transcribed verbatim. Reading and re-reading cut and paste techniques, and integration were used to establish codes, categories, themes, and description.</p> <p>Results</p> <p>Diverse and sometimes opposite changes in somatic symptoms, psychological symptoms, productivity, ecological relationships, doctor-client relationships, ethical issues, and change of life style were the major problem domains.</p> <p>Conclusions</p> <p>Clients reported conflicting experiences in several areas of their lives after tubal sterilization. Management, including awareness of the particular features of the client, is needed to decrease the likelihood of psychosocial morbidity and/or to select clients in need of sterilization.</p
Fires can benefit plants by disrupting antagonistic interactions
Fire has a key role in the ecology and evolution of many ecosystems, yet its effects on plant–insect interactions are poorly understood. Because interacting species are likely to respond to fire differently, disruptions of the interactions are expected. We hypothesized that plants that regenerate after fire can benefit through the disruption of their antagonistic interactions. We expected stronger effects on interactions with specialist predators than with generalists. We studied two interactions between two Mediterranean plants (Ulex parviflorus, Asphodelus ramosus) and their specialist seed predators after large wildfires. In A. ramosus we also studied the generalist herbivores. We sampled the interactions in burned and adjacent unburned areas during 2 years by estimating seed predation, number of herbivores and fruit set. To assess the effect of the distance to unburned vegetation we sampled plots at two distance classes from the fire perimeter. Even 3 years after the fires, Ulex plants experienced lower seed damage by specialists in burned sites. The presence of herbivores on Asphodelus decreased in burned locations, and the variability in their presence was significantly related to fruit set. Generalist herbivores were unaffected. We show that plants can benefit from fire through the disruption of their antagonistic interactions with specialist seed predators for at least a few years. In environments with a long fire history, this effect might be one additional mechanism underlying the success of fire-adapted plants
Comparative genomics of Cluster O mycobacteriophages
Mycobacteriophages - viruses of mycobacterial hosts - are genetically diverse but morphologically are all classified in the Caudovirales with double-stranded DNA and tails. We describe here a group of five closely related mycobacteriophages - Corndog, Catdawg, Dylan, Firecracker, and YungJamal - designated as Cluster O with long flexible tails but with unusual prolate capsids. Proteomic analysis of phage Corndog particles, Catdawg particles, and Corndog-infected cells confirms expression of half of the predicted gene products and indicates a non-canonical mechanism for translation of the Corndog tape measure protein. Bioinformatic analysis identifies 8-9 strongly predicted SigA promoters and all five Cluster O genomes contain more than 30 copies of a 17 bp repeat sequence with dyad symmetry located throughout the genomes. Comparison of the Cluster O phages provides insights into phage genome evolution including the processes of gene flux by horizontal genetic exchange
Three-dimensional structure of a viral genome-delivery portal vertex.
DNA viruses such as bacteriophages and herpesviruses deliver their genome into and out of the capsid through large proteinaceous assemblies, known as portal proteins. Here, we report two snapshots of the dodecameric portal protein of bacteriophage P22. The 3.25-Å-resolution structure of the portal-protein core bound to 12 copies of gene product 4 (gp4) reveals a ~1.1-MDa assembly formed by 24 proteins. Unexpectedly, a lower-resolution structure of the full-length portal protein unveils the unique topology of the C-terminal domain, which forms a ~200-Å-long α-helical barrel. This domain inserts deeply into the virion and is highly conserved in the Podoviridae family. We propose that the barrel domain facilitates genome spooling onto the interior surface of the capsid during genome packaging and, in analogy to a rifle barrel, increases the accuracy of genome ejection into the host cell
Relationship between birth weight and retinal microvasculature in newborn infants
Objective: The purposes of this study were to determine the normal retinal microvasculature measurements in human infants who are born at term and to determine whether birth weight influences measurements of retinal microvasculature. Study Design: Retinal arteriole and venule measurements were obtained in a cohort of 24 infants who were born at term. Digital images of both the retinas were obtained using a digital retinal camera after pupillary dilation. Result: In all, 24 newborn infants born at term (12 females and 12 males) were analyzed in this study. The measured retinal arteriole diameters were from 66.8 to 147.8 μm (mean, 94.2±19.6 μm), and the venule diameters were from 102.0 to 167.8 μm (mean, 135.2±19.1 μm). Seven babies in the sample had low birth weight (LBW), while 17 babies were born with normal weight. Babies with lower birth weights had larger arteriole (113.1±17.9 μm vs 86.4±14.4 μm; P=0.0009) and venule diameters (151.7±14.9 μm vs 128.4±16.9 μm; P=0.0040). Conclusion: Retinal venules and arterioles in LBW babies are larger compared with those of normal-birth-weight babies. We postulate that the difference observed in our study was due to in utero pathophysiological changes that occurred in the cerebral circulation of growth-restricted fetuses
Linking direct and indirect pathways mediating earthworms, deer, and understory composition in Great Lakes forests
Ahistorical drivers such as nonnative invasive earthworms and high deer densities can have substantial impacts on ecosystem processes and plant community composition in temperate and boreal forests of North America. To assess the roles of earthworm disturbance, deer, and environmental factors in the understory, we sampled 125 mixed temperate-boreal forest sites across the western Great Lakes region. We utilized structural equation modeling (SEM) to address the hypothesis that earthworm disturbance to the upper soil horizons and selective herbivory by deer are associated with depauperate understory plant communities dominated by graminoid and nonnative species. Evidence of earthworm activity was found at 93 % of our sites and 49 % had high to very high severity earthworm disturbance. The SEM fit the data well and indicated that widespread nonnative earthworm disturbance and high deer densities had similar magnitudes of impact on understory plant communities and that these impacts were partially mediated by environmental characteristics. One-third of the variation in earthworm disturbance was explained by soil pH, precipitation, and litter quality. Deer density and earthworm disturbance both increased graminoid cover while environmental variables showed direct and indirect relationships. For example, the positive relationship between temperature and graminoids was indirect through a positive temperature effect on deer density. This research characterizes an integrated set of key environmental variables driving earthworm disturbance and deer impacts on the forest understory, facilitating predictions of the locations and severity of future change in northern temperate and boreal forest ecosystems
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