257 research outputs found

    Developing a model pipeline for VERITAS stellar intensity interferometry

    Get PDF
    Rotation, which affects a star\u27s evolution, is a fundamental stellar parameter and is manifest for rapidly-rotating stars by significant aspherical distortion, hotter polar temperatures and cooler equators, relative to slowly-rotating stars. Long-baseline interferometry at near-infrared wavelengths has directly imaged the brightest rapidly-rotating stars, constraining their shapes and surface temperature gradients, however observations at shorter wavelengths, near 400 nanometers, are predicted to have much higher surface-brightness contrast. To accurately predict such observations, we developed a pipeline for generating simulated data for detailed planning of observations by the Very Energetic Radiation Imaging Telescope Array System (VERITAS) stellar intensity interferometer. This poster displays synthetic images, interferometric observables, and spectral energy distributions for four rapidly-rotating stars: Alderamin, Rasalhague, Regulus, and Vega. We found significant differences between models at 1746 nm and 400 nm; which could be tested by VERTIAS observations, at least for Regulus, later this spring

    Incomplete pneumolysin oligomers form membrane pores

    No full text
    Pneumolysin is a member of the cholesterol-dependent cytolysin (CDC) family of pore-forming proteins that are produced as water-soluble monomers or dimers, bind to target membranes and oligomerize into large ring-shaped assemblies comprising approximately 40 subunits and approximately 30 nm across. This pre-pore assembly then refolds to punch a large hole in the lipid bilayer. However, in addition to forming large pores, pneumolysin and other CDCs formsmaller lesions characterized by low electrical conductance. Owing to the observation of arc-like (rather than full-ring) oligomers by electron microscopy, it has been hypothesized that smaller oligomers explain smaller functional pores. To investigate whether this is the case, we performed cryo-electron tomography of pneumolysin oligomers on model lipid membranes. We then used sub-tomogram classification and averaging to determine representative membrane-bound low-resolution structures and identified pre-pores versus pores by the presence of membrane within the oligomeric curve. We found pre-pore and pore forms of both complete (ring) and incomplete (arc) oligomers and conclude that arc-shaped oligomeric assemblies of pneumolysin can form pores. As the CDCs are evolutionarily related to the membrane attack complex/perforin family of proteins, which also form variably sized pores, our findings are of relevance to that class of proteins as well

    Spinning Slow and Fast: Stellar Atmosphere Models for β Ursae Majoris and α Leonis.

    Get PDF
    Angular diameter measurements by the Very Energetic Radiation Imaging Telescope Array System (VERITAS) Stellar Intensity Interferometer (SII) in a waveband near 400 nm complement existing angular diameter measurements in the near-infrared. VSII observations will test fundamental predictions of stellar atmosphere models and should be more sensitive to limb darkening and gravity darkening effects than measurements in the near-IR, however, the magnitude of this difference has not been systematically explored in the literature. In order to investigate the synthetic interferometric (as well as spectroscopic) appearance of stars in the blue relative to the near-IR, we have computed grids of model atmospheres appropriate for six stars observed by VSII: four rapid rotators α Cep, α Leo, α Lyr, and η UMa, along with two slow rotators β UMa and β CMa. We predict these stars will appear smaller in angular size and exhibit higher visibilities in the first lobe of the visibility curve at 400 nm relative to 1746 nm at the same spatial frequencies, consistent with our expectations. This poster focuses on two of these stars, β UMa and α Leo. Synthetic spectra match archival spectra around 400nm best for β UMa and α Leo. We will compare our interferometric predictions for the nearly spherical, slow rotator, β UMa, and the highly distorted, rapid rotator, α Leo

    Phenotypic Variation in Adaptive Traits Among Western Populations of Showy Milkweed (\u3cem\u3eAsclepias speciose\u3c/em\u3e)

    Get PDF
    Monarch butterfly (Danaus plexippus) populations have suffered extensive declines due to habitat loss and fragmentation in wintering, migrating, and breeding ranges. Urbanization and intensive agricultural practices have reduced populations of milkweeds which monarchs depend on for reproduction. With increasing conservation concern and a prospective Endangered Species Act listing, there is increased motivation for habitat restoration projects that enhance milkweeds. Our project seeks to describe variation in adaptive traits and phenology among populations of showy milkweed from the Western US. We conducted common garden experiments, in which we propagated and grew individuals from 36 populations ranging from California to South Dakota. We used remotely sensed climate data in conjunction with morphological measures and plant growth data to identify variation in adaptive traits and correlate them to elevation and climate variation. Here we present the results of our analyses and their implications for defining seed transfer zones for showy milkweed in the context of monarch butterfly habitat restoration

    Outcomes of polytrauma patients with diabetes mellitus.

    Get PDF
    BACKGROUND: The impact of diabetes mellitus in patients with multiple system injuries remains obscure. This study was designed to increase knowledge of outcomes of polytrauma in patients who have diabetes mellitus. METHODS: Data from the Trauma Audit and Research Network was used to identify patients who had suffered polytrauma during 2003 to 2011. These patients were filtered to those with known outcomes, then separated into those with diabetes, those known to have other co-morbidities but not diabetes and those known not to have any co-morbidities or diabetes. The data were analyzed to establish if patients with diabetes had differing outcomes associated with their diabetes versus the other groups. RESULTS: In total, 222 patients had diabetes, 2,558 had no past medical co-morbidities (PMC), 2,709 had PMC but no diabetes. The diabetic group of patients was found to be older than the other groups (P <0.05). A higher mortality rate was found in the diabetic group compared to the non-PMC group (32.4% versus 12.9%), P <0.05). Rates of many complications including renal failure, myocardial infarction, acute respiratory distress syndrome, pulmonary embolism and deep vein thrombosis were all found to be higher in the diabetic group. CONCLUSIONS: Close monitoring of diabetic patients may result in improved outcomes. Tighter glycemic control and earlier intervention for complications may reduce mortality and morbidity

    Conserved molecular interactions in centriole-to-centrosome conversion.

    Get PDF
    Centrioles are required to assemble centrosomes for cell division and cilia for motility and signalling. New centrioles assemble perpendicularly to pre-existing ones in G1-S and elongate throughout S and G2. Fully elongated daughter centrioles are converted into centrosomes during mitosis to be able to duplicate and organize pericentriolar material in the next cell cycle. Here we show that centriole-to-centrosome conversion requires sequential loading of Cep135, Ana1 (Cep295) and Asterless (Cep152) onto daughter centrioles during mitotic progression in both Drosophila melanogaster and human. This generates a molecular network spanning from the inner- to outermost parts of the centriole. Ana1 forms a molecular strut within the network, and its essential role can be substituted by an engineered fragment providing an alternative linkage between Asterless and Cep135. This conserved architectural framework is essential for loading Asterless or Cep152, the partner of the master regulator of centriole duplication, Plk4. Our study thus uncovers the molecular basis for centriole-to-centrosome conversion that renders daughter centrioles competent for motherhood.J.F., Z.L., S.S. and N.S.D. are supported from Programme Grant to D.M.G. from Cancer Research UK. H.R. is supported from MRC Programme Grant to D.M.G. J.F. thank the British Academy and the Royal Society for Newton International Fellowship and Z.L. thanks the Federation of European Biochemical Societies for the Long-Term postdoctoral Fellowship. The authors thank Nicola Lawrence and Alex Sossick for assistance with 3D-SIM.This is the author accepted manuscript. The final version is available from NPG via http://dx.doi.org/10.1038/ncb327

    Individual Liberty and the Importance of the Concept of the People

    Get PDF
    UID/FIL/00183/2013Through publically agreed laws that correspond to a common set of public restrictions, the ‘people as a sovereign body’ serves to protect against violations of individual liberty and despotic power. Where no such common body exists, individuals are deprived of this protection. In such cases, individuals must obey without liberty, while those in power command under a state of license. Neoliberal theorists maintain that any common personality, with its corresponding set of public and arbitrary positive and negative restrictions on liberty, undermines individual liberty. Neoliberal theory only allows for private restrictions on liberty. Against these neoliberal assumptions, we argue that rejecting public restrictions on liberty does not promote individual liberty. To the 1᢫ ᢬ ᢭ ᢮ 1 contrary, it creates conditions in which free individuals become servile and political inequality becomes entrenched, where citizens are divided into those who obey and those who command. Tracing the consequences of neoliberalism, we argue that unless we take seriously both the people as a political category and the right to equal and reciprocal coercion, individual liberty will be at risk. We also argue that neoliberalism ultimately leads to the total exclusion of certain citizens under the veil of full liberty. With the vanishing of the people’s will comes the utter disappearance of certain citizens, who live in the spontaneous society as if they were stateless or lawless persons. To better understand the connections between the rejection of the concept of the people, private restrictions on liberty and the fostering of the servile citizen, this paper considers the political philosophy of Hayek and Nozick. It also considers key ideas from Locke and Kant—theorists who, despite the differences between their philosophical perspectives, and despite the fact that they both provided crucial inspiration for Hayek’s political economy and Nozick’s libertarianism, stressed the protective role of the people with regard to individual liberty.publishersversionpublishe

    Multicenter retrospective analysis of 581 patients with primary intestinal non-hodgkin lymphoma from the Consortium for Improving Survival of Lymphoma (CISL)

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Primary intestinal non-Hodgkin lymphoma (NHL) is a heterogeneous disease with regard to anatomic and histologic distribution. Thus, analyses focusing on primary intestinal NHL with large number of patients are warranted.</p> <p>Methods</p> <p>We retrospectively analyzed 581 patients from 16 hospitals in Korea for primary intestinal NHL in this retrospective analysis. We compared clinical features and treatment outcomes according to the anatomic site of involvement and histologic subtypes.</p> <p>Results</p> <p>B-cell lymphoma (n = 504, 86.7%) was more frequent than T-cell lymphoma (n = 77, 13.3%). Diffuse large B-cell lymphoma (DLBCL) was the most common subtype (n = 386, 66.4%), and extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) was the second most common subtype (n = 61, 10.5%). B-cell lymphoma mainly presented as localized disease (Lugano stage I/II) while T-cell lymphomas involved multiple intestinal sites. Thus, T-cell lymphoma had more unfavourable characteristics such as advanced stage at diagnosis, and the 5-year overall survival (OS) rate was significantly lower than B-cell lymphoma (28% versus 71%, P < 0.001). B symptoms were relatively uncommon (20.7%), and bone marrow invasion was a rare event (7.4%). The ileocecal region was the most commonly involved site (39.8%), followed by the small (27.9%) and large intestines (21.5%). Patients underwent surgery showed better OS than patients did not (5-year OS rate 77% versus 57%, P < 0.001). However, this beneficial effect of surgery was only statistically significant in patients with B-cell lymphomas (P < 0.001) not in T-cell lymphomas (P = 0.460). The comparison of survival based on the anatomic site of involvement showed that ileocecal regions had a better 5-year overall survival rate (72%) than other sites in consistent with that ileocecal region had higher proportion of patients with DLBCL who underwent surgery. Age > 60 years, performance status ≥ 2, elevated serum lactate dehydrogenase, Lugano stage IV, presence of B symptoms, and T-cell phenotype were independent prognostic factors for survival.</p> <p>Conclusions</p> <p>The survival of patients with ileocecal region involvement was better than that of patients with involvement at other sites, which might be related to histologic distribution, the proportion of tumor stage, and need for surgical resection.</p
    corecore