Resolved Imaging of the HD191089 Debris Disc

Two thirds of the F star members of the 12 Myr old Beta Pictoris Moving Group (BPMG) show significant excess emission in the mid-infrared, several million years after the expected dispersal of the protoplanetary disc. Theoretical models of planet formation suggest that this peak in the mid-infrared emission could be due to the formation of Pluto-sized bodies in the disc, which ignite the collisional cascade and enhance the production of small dust. Here we present resolved mid-infrared imaging of the disc of HD191089 (F5V in the BPMG) and consider its implications for the state of planet formation in this system. HD191089 was observed at 18.3 microns using T-ReCS on Gemini South and the images were compared to models of the disc to constrain the radial distribution of the dust. The emission observed at 18.3 microns is shown to be significantly extended beyond the PSF at a position angle of 80 degrees. This is the first time dust emission has been resolved around HD191089. Modelling indicates that the emission arises from a dust belt from 28-90 AU, inclined at 35 degrees from edge on with very little emission from the inner 28AU of the disc, indicating the presence of an inner cavity. The steep slope of the inner edge is more consistent with truncation by a planet than with ongoing stirring. A tentative brightness asymmetry F(W)/F(E)=0.80+/-0.12 (1.8 sigma) between the two sides of the disc could be evidence for perturbations from a massive body on an eccentric orbit in the system.Comment: 11 Pages Accepted to MNRA

Spt5 Cooperates with Human Immunodeficiency Virus Type 1 Tat by Preventing Premature RNA Release at Terminator Sequences

The human immunodeficiency virus type 1 (HIV-1) Tat protein activates transcription elongation by stimulating the Tat-activated kinase (TAK/p-TEFb), a protein kinase composed of CDK9 and its cyclin partner, cyclin T1. CDK9 is able to hyperphosphorylate the carboxyl-terminal domain (CTD) of the large subunit of RNA polymerase during elongation. In addition to TAK, the transcription elongation factor Spt5 is required for the efficient activation of transcriptional elongation by Tat. To study the role of Spt5 in HIV transcription in more detail, we have developed a three-stage Tat-dependent transcription assay that permits the isolation of active preinitiation complexes, early-stage elongation complexes, and Tat-activated elongation complexes. Spt5 is recruited in the transcription complex shortly after initiation. After recruitment of Tat during elongation through the transactivation response element RNA, CDK9 is activated and induces hyperphosphorylation of Spt5 in parallel to the hyperphosphorylation of the CTD of RNA polymerase II. However, immunodepletion experiments demonstrate that Spt5 is not required for Tat-dependent activation of the kinase. Chase experiments using the Spt5-depleted extracts demonstrate that Spt5 is not required for early elongation. However, Spt5 plays an important role in late elongation by preventing the premature dissociation of RNA from the transcription complex at terminator sequences and reducing the amount of polymerase pausing at arrest sites, including bent DNA sequences. This novel biochemical function of Spt5 is analogous to the function of NusG, an elongation factor found in Escherichia coli that enhances RNA polymerase stability on templates and shows sequence similarity to Spt5

A Mindfulness Program Manual for People With Dementia

This article describes a 10-session group-based Mindfulness Program for people with mild to moderate dementia. It aims to equip people with dementia with skills to manage psychological distress, with support from carers. The Mindfulness Program was developed through reviews of existing literature, consultation with experts, and a focus group with people with dementia. In a randomized controlled feasibility and pilot trial with people with mild to moderate dementia in care homes, it was found to significantly increase quality of life. The manual presented here is designed to be administered flexibly to promote participants' personhood. The protocol is designed for use by therapists with experience in practicing mindfulness meditation

Late Pleistocene Vertebrate, Plant and Insect Remains from the lnnerkip Site, Southwestern Ontario

Remains of white-tailed deer (Odocoileus virginianus), meadow voles (Microtus pennsylvanicus), muskrat (Ondatra zibethicus) and Blanding's turtle (Emydoidea blandingi) have been recovered from a peat deposit exposed on a tributary of the Thames River in southwestern Ontario. Numerous insect fossils, principally Coleoptera, and a variety of plants recovered from the same stratigraphie horizon have permitted a partial reconstruction of a larger community at the site of peat deposition. The plant, vertebrate and invertebrate fossils represent part of an assemblage which existed in. or beside, a small pond. Deposition probably occurred at the end of the Sangamon Interglaciation (Isotope Stage 5e) or during warm Early Wisconsinan interstadial (Isotope Stage 5c or 5a).Les restes de cerf de Virginie (Odocoileus virginianus), de campagnols des champs (Microtus pennsylvanicus), de rat musqué (Ondatra zibethicus) et de tortue mouchetée (Emydoidea blandingi) ont été recueillis dans un dépôt de tourbe à découvert d'un tributaire de la rivière Thames. De nombreux fossiles d'insectes, surtout de coléoptères, et une certaine variété de végétaux faisant partie du même horizon stratigraphique ont permis de faire la reconstitution, du moins partielle, d'une communauté plus importante au site de la mise en place de la tourbe. Les fossiles de végétaux, de vertébrés et d'invertébrés représentent une partie d'un regroupement qui a vécu dans un petit étang ou à proximité. La mise en place a probablement eu lieu à la fin de l'Interglaciaire du Sangamonien (stade isotopique 5e) ou au cours d'un interstade chaud du Wisconsinien inférieur (stade isotopique 5c ou 5a).Reste von Virginia-Hirsch (Odocoileus virginianus), Wiesenmâusen (Microtus pennsylvanicus), Bisamratte (Ondatra zibethicus) und Blading's Schildkrôte (Emydoidea blandingi) wurden aus einer Torfablagerung wiedergewonnen, die an einem Nebenfluss des Thames River offengelegt war. Zahlreiche Insekten-fossile, hauptsàchlich Coleoptera, und eine Vielfalt von Pflanzen von demselben stratigraphischen Horizont erlaubten eine teilweise Rekonstruktion einer grôsseren Lebensgemeinschaft am Ort der Torfablagerung. Die Fossile von Pflanzen, Wirbeltieren und Wirbellosen sind Teil einer Einheit, die in oder neben einem kleinen Teich existierte. Die Ablagerung fand wahrscheinlich am Ende des sangamonischen Interglazial (lsotop Stadium 5e) oder wàhrend des fruhen Wisconsinischen Interstadial (lsotop Stadium 5c oder 5a) statt

Are commercial providers a viable option for clinical bacterial sequencing?

Bacterial whole-genome sequencing in the clinical setting has the potential to bring major improvements to infection control and clinical practice. Sequencing instruments are not currently available in the majority of routine microbiology laboratories worldwide, but an alternative is to use external sequencing providers. To foster discussion around this we investigated whether send-out services were a viable option. Four providers offering MiSeq sequencing were selected based on cost and evaluated based on the service provided and sequence data quality. DNA was prepared from five methicillin-resistant Staphylococcus aureus (MRSA) isolates, four of which were investigated during a previously published outbreak in the UK together with a reference MRSA isolate (ST22 HO 5096 0412). Cost of sequencing per isolate ranged from £155 to £342 and turnaround times from DNA postage to arrival of sequence data ranged from 12 to 63 days. Comparison of commercially generated genomes against the original sequence data demonstrated very high concordance, with no more than one single nucleotide polymorphism (SNP) difference on core genome mapping between the original sequences and the new sequence for all four providers. Multilocus sequence type could not be assigned based on assembly for the two cheapest sequence providers due to fragmented assemblies probably caused by a lower output of sequence data per isolate. Our results indicate that external providers returned highly accurate genome data, but that improvements are required in turnaround time to make this a viable option for use in clinical practice

The therapeutic efficacy and macrofilaricidal activity of doxycycline for the treatment of river blindness

Background. Onchocerca volvulus and lymphatic filariae, causing river blindness and elephantiasis, depend on endosymbiotic Wolbachia bacteria for growth, development, fertility, and survival. Clinical trials have shown that doxycycline treatment eliminates Wolbachia, causing long-term sterilization of adult female filariae and effecting potent macrofilaricidal activity. The continual reinfection by drug-naive worms that occurs in these trial settings dilutes observable anti-Wolbachia and antifilarial effects, making it difficult to estimate therapeutic efficacy and compare different doxycycline regimens, evaluated at different times after treatment. Methods. A meta-analytical modeling framework is developed to link all usable data collected from clinical trials measuring the Wolbachia status and viability of individual female adult worms collected at various times after treatment with 4, 5, or 6 weeks of daily 100 or 200 mg oral doxycycline. The framework is used to estimate efficacy parameters that are not directly measurable as trial outcomes. Results. The estimated efficacy of doxycycline (the maximum proportional reduction in the percentage of adult female O. volvulus positive for Wolbachia) is 91%–94% on average, irrespective of the treatment regimen. Efficacy is >95% in the majority of trial participants. The life span of Wolbachia-depleted worms is reduced by 70%–80%, from approximately 10 years to 2–3 years. Conclusions. The efficacy parameters are pertinent to the prospects of using doxycycline on a “test and treat” basis for onchocerciasis control and confirm doxycycline as a potent macrofilaricidal therapy. The modeling approach is more generally relevant to the design and evaluation of clinical trials for antifilarial drugs conducted in endemic settings

Reducing Plasmodium falciparum malaria transmission in Africa: a model-based evaluation of intervention strategies.

BACKGROUND: Over the past decade malaria intervention coverage has been scaled up across Africa. However, it remains unclear what overall reduction in transmission is achievable using currently available tools. METHODS AND FINDINGS: We developed an individual-based simulation model for Plasmodium falciparum transmission in an African context incorporating the three major vector species (Anopheles gambiae s.s., An. arabiensis, and An. funestus) with parameters obtained by fitting to parasite prevalence data from 34 transmission settings across Africa. We incorporated the effect of the switch to artemisinin-combination therapy (ACT) and increasing coverage of long-lasting insecticide treated nets (LLINs) from the year 2000 onwards. We then explored the impact on transmission of continued roll-out of LLINs, additional rounds of indoor residual spraying (IRS), mass screening and treatment (MSAT), and a future RTS,S/AS01 vaccine in six representative settings with varying transmission intensity (as summarized by the annual entomological inoculation rate, EIR: 1 setting with low, 3 with moderate, and 2 with high EIRs), vector-species combinations, and patterns of seasonality. In all settings we considered a realistic target of 80% coverage of interventions. In the low-transmission setting (EIR approximately 3 ibppy [infectious bites per person per year]), LLINs have the potential to reduce malaria transmission to low levels (90%) or novel tools and/or substantial social improvements will be required, although considerable reductions in prevalence can be achieved with existing tools and realistic coverage levels. CONCLUSIONS: Interventions using current tools can result in major reductions in P. falciparum malaria transmission and the associated disease burden in Africa. Reduction to the 1% parasite prevalence threshold is possible in low- to moderate-transmission settings when vectors are primarily endophilic (indoor-resting), provided a comprehensive and sustained intervention program is achieved through roll-out of interventions. In high-transmission settings and those in which vectors are mainly exophilic (outdoor-resting), additional new tools that target exophagic (outdoor-biting), exophilic, and partly zoophagic mosquitoes will be required

Asymmetric Heating of the HR 4796A Dust Ring Due to Pericenter Glow

We have obtained new resolved images of the well-studied HR 4796A dust ring at 18 and 25 microns with the 8-meter Gemini telescopes. These images confirm the previously observed spatial extent seen in mid-IR, near-IR, and optical images of the source. We detect brightness and temperature asymmetries such that dust on the NE side is both brighter and warmer than dust in the SW. We show that models of so-called pericenter glow account for these asymmetries, thus both confirming and extending our previous analyses. In this scenario, the center of the dust ring is offset from the star due to gravitational perturbations of a body with an eccentric orbit that has induced a forced eccentricity on the dust particle orbits. Models with 2-micron silicate dust particles and a forced eccentricity of 0.06 simultaneously fit the observations at both wavelengths. We also show that parameters used to characterize the thermal-emission properties of the disk can also account for the disk asymmetry observed in shorter-wavelength scattered-light images.Comment: accepted for publication in A&A; 7 pages, 4 figure