16,033 research outputs found
Probing a non-biaxial behavior of infinitely thin hard platelets
We give a criterion to test a non-biaxial behavior of infinitely thin hard
platelets of symmetry based upon the components of three order
parameter tensors. We investigated the nematic behavior of monodisperse
infinitely thin rectangular hard platelet systems by using the criterion.
Starting with a square platelet system, and we compared it with rectangular
platelet systems of various aspect ratios. For each system, we performed
equilibration runs by using isobaric Monte Carlo simulations. Each system did
not show a biaxial nematic behavior but a uniaxial nematic one, despite of the
shape anisotropy of those platelets. The relationship between effective
diameters by simulations and theoretical effective diameters of the above
systems was also determined.Comment: Submitted to JPS
Domains in Melts of Comb-Coil Diblock Copolymers: Superstrong Segregation Regime
Conditions for the crossover from the strong to the superstrong segregation regime are analyzed for the case of comb-coil diblock copolymers. It is shown that the critical interaction energy between the components required to induce the crossover to the superstrong segregation regime is inversely proportional to mb = 1 + n/m, where n is the degree of polymerization of the side chain and m is the distance between successive grafting points. As a result, the superstrong segregation regime, being rather rare in the case of ordinary block copolymers, has a much better chance to be realized in the case of diblock copolymers with combs grafted to one of the blocks.
Clinical outcome data for symptomatic breast cancer: the breast cancer clinical outcome measures (BCCOM) project
Background: Data collection for screen-detected breast cancer in the UK is fully funded which has led to improvements in clinical practice. However data on symptomatic breast cancer are deficient, and the aim of this project was to monitor the current practice.
Methods: A data set was designed together with surrogate outcome measures to reflect best practice. Data from cancer registries initially required the consent of clinicians, but in the third year anonymised data were available.
Results: The quality of data improved but this varied by region and only a third of cases were validated by clinicians. Regional variations in mastectomy rates were identified and one third of patients who underwent conservative surgery for invasive breast cancer were not recorded as receiving radiotherapy.
Conclusions: National data are essential to ensure that all patients receive appropriate treatment for breast cancer, but variations still exist in the UK and further improvement in data capture is required
The interaction of phylloxera infection, rootstock, and irrigation on young Concord grapevine growth
Concord roots are moderately resistant to phylloxera, which form nodosities on the fine roots and weaken the root system. Rootstocks and vineyard floor management both have the potential to eliminate or reduce the effect of phylloxera in New York Concord vineyards. Young, container-grown Concord grapevines were used to evaluate the interaction between rootstock (own-rooted, Couderc 3309), irrigation, and phylloxera infection on vine growth. Phylloxera inoculation alone caused a 21 % decrease in vine dry mass and lack of irrigation (mid-day stem water potential: -0.9 to -1.0 M Pa) alone caused a 34 % decrease in vine dry mass. The combination of phylloxera stress and water stress was additive and caused a 54 % decrease in vine dry mass. Because C3309 rootstock is resistant to phylloxera, the grafted vines showed a response to irrigation but not phylloxera inoculation. This container study shows the potential benefits of irrigating own-rooted Concord grapevines or the use of rootstocks without irrigation to withstand phylloxera infection.
Decadal trends in aerosol chemical composition at Barrow, Alaska: 1976–2008
Aerosol measurements at Barrow, Alaska during the past 30 years have identified the long range transport of pollution associated with Arctic Haze as well as ocean-derived aerosols of more local origin. Here, we focus on measurements of aerosol chemical composition to assess (1) trends in Arctic Haze aerosol and implications for source regions, (2) the interaction between pollution-derived and ocean-derived aerosols and the resulting impacts on the chemistry of the Arctic boundary layer, and (3) the response of aerosols to a changing climate. Aerosol chemical composition measured at Barrow, AK during the Arctic haze season is compared for the years 1976–1977 and 1997–2008. Based on these two data sets, concentrations of non-sea salt (nss) sulfate (SO<sub>4</sub><sup>=</sup>) and non-crustal (nc) vanadium (V) have decreased by about 60% over this 30 year period. Consistency in the ratios of nss SO<sub>4</sub><sup>=</sup>/ncV and nc manganese (Mn)/ncV between the two data sets indicates that, although emissions have decreased in the source regions, the source regions have remained the same over this time period. The measurements from 1997–2008 indicate that, during the haze season, the nss SO<sub>4</sub><sup>=</sup> aerosol at Barrow is becoming less neutralized by ammonium (NH<sub>4</sub><sup>+</sup>) yielding an increasing sea salt aerosol chloride (Cl<sup>&minus;</sup>) deficit. The expected consequence is an increase in the release of Cl atoms to the atmosphere and a change in the lifetime of volatile organic compounds (VOCs) including methane. In addition, summertime concentrations of biogenically-derived methanesulfonate (MSA<sup>&minus;</sup>) and nss SO<sub>4</sub><sup>=</sup> are increasing at a rate of 12 and 8% per year, respectively. Further research is required to assess the environmental factors behind the increasing concentrations of biogenic aerosol
Development of planar pixel modules for the ATLAS high luminosity LHC tracker upgrade
The high-luminosity LHC will present significant challenges for tracking systems. ATLAS is preparing to upgrade the entire tracking system, which will include a significantly larger pixel detector. This paper reports on the development of large area planar detectors for the outer pixel layers and the pixel endcaps. Large area sensors have been fabricated and mounted onto 4 FE-I4 readout ASICs, the so-called quad-modules, and their performance evaluated in the laboratory and testbeam. Results from characterisation of sensors prior to assembly, experience with module assembly, including bump-bonding and results from laboratory and testbeam studies are presented
Ambitious partnership needed for reliable climate prediction.
Current global climate models struggle to represent precipitation and related extreme events, with serious implications for the physical evidence base to support climate actions. A leap to kilometre-scale models could overcome this shortcoming but requires collaboration on an unprecedented scale
Regulation of Lymphocyte Function by PPARγ: Relevance to Thyroid Eye Disease-Related Inflammation
Thyroid eye disease (TED) is an autoimmune condition in which intense inflammation leads to orbital tissue remodeling, including the accumulation of extracellular macromolecules and fat. Disease progression depends upon interactions between lymphocytes and orbital fibroblasts. These cells engage in a cycle of reciprocal activation which produces the tissue characteristics of TED. Peroxisome proliferator-activated receptor-γ (PPARγ) may play divergent roles in this process, both attenuating and promoting disease progression. PPARγ has anti-inflammatory activity, suggesting that it could interrupt intercellular communication. However, PPARγ activation is also critical to adipogenesis, making it a potential culprit in the pathological fat accumulation associated with TED. This review explores the role of PPARγ in TED, as it pertains to crosstalk between lymphocytes and fibroblasts and the development of therapeutics targeting cell-cell interactions mediated through this signaling pathway
Filmic geographies: audio-visual, embodied-material
Although conventionally described as a ‘visual’ method, film-making is also increasingly used within research on embodiment. However, much remains to be said about the ability of filmic methods to enhance researchers’ capacity to think and research through the body. Drawing on my experience of making four research films, in this paper, I attempt to advance this agenda in three steps. First, I introduce anthropological work on the filming body to shed light on the technologically-mediated encounters that enfold around a camera and discuss how they might inform geographical thinking. Second, I describe the corporeally-mediated object ecologies that take shape within the filming setting and highlight how a camera might make objects ‘speak’. Finally, I discuss the affective dimension of screening research films to research participants and the contribution of such intense events to the articulation of collective matters of concerns. Through these three themes, I make the case for understanding knowledge production as located not merely in encounters with filmed audio-visual content, but also in the embodied-material encounters of bodies and objects around the filming and screening apparatus. I finally discuss the implications of these reflections for conceptualising the ‘body’ within embodied methods in social and cultural geography
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