696 research outputs found
Slow equivariant lump dynamics on the two sphere
The low-energy, rotationally equivariant dynamics of n CP^1 lumps on S^2 is
studied within the approximation of geodesic motion in the moduli space of
static solutions. The volume and curvature properties of this moduli space are
computed. By lifting the geodesic flow to the completion of an n-fold cover of
the moduli space, a good understanding of nearly singular lump dynamics within
this approximation is obtained.Comment: 12 pages, 3 figure
The geodesic approximation for lump dynamics and coercivity of the Hessian for harmonic maps
The most fruitful approach to studying low energy soliton dynamics in field
theories of Bogomol'nyi type is the geodesic approximation of Manton. In the
case of vortices and monopoles, Stuart has obtained rigorous estimates of the
errors in this approximation, and hence proved that it is valid in the low
speed regime. His method employs energy estimates which rely on a key
coercivity property of the Hessian of the energy functional of the theory under
consideration. In this paper we prove an analogous coercivity property for the
Hessian of the energy functional of a general sigma model with compact K\"ahler
domain and target. We go on to prove a continuity property for our result, and
show that, for the CP^1 model on S^2, the Hessian fails to be globally coercive
in the degree 1 sector. We present numerical evidence which suggests that the
Hessian is globally coercive in a certain equivariance class of the degree n
sector for n>1. We also prove that, within the geodesic approximation, a single
CP^1 lump moving on S^2 does not generically travel on a great circle.Comment: 29 pages, 1 figure; typos corrected, references added, expanded
  discussion of the main function spac
Application of pharmacogenomics and bioinformatics to exemplify the utility of human <i>ex vivo</i> organoculture models in the field of precision medicine
Here we describe a collaboration between industry, the National Health Service (NHS) and academia that sought to demonstrate how early understanding of both pharmacology and genomics can improve strategies for the development of precision medicines. Diseased tissue ethically acquired from patients suffering from chronic obstructive pulmonary disease (COPD), was used to investigate inter-patient variability in drug efficacy using ex vivo organocultures of fresh lung tissue as the test system. The reduction in inflammatory cytokines in the presence of various test drugs was used as the measure of drug efficacy and the individual patient responses were then matched against genotype and microRNA profiles in an attempt to identify unique predictors of drug responsiveness. Our findings suggest that genetic variation in CYP2E1 and SMAD3 genes may partly explain the observed variation in drug response
Proposal for a revised definition of dilated cardiomyopathy, hypokinetic non-dilated cardiomyopathy, and its implications for clinical practice: a position statement of the ESC working group on myocardial and pericardial diseases
In this paper the Working Group on Myocardial and Pericardial Disease proposes a revised definition of dilated cardiomyopathy (DCM) in an attempt to bridge the gap between our recent understanding of the disease spectrum and its clinical presentation in relatives, which is key for early diagnosis and the institution of potential preventative measures. We also provide practical hints to identify subsets of the DCM syndrome where aetiology directed management has great clinical relevance
A new hammer to crack an old nut : interspecific competitive resource capture by plants is regulated by nutrient supply, not climate
Peer reviewedPublisher PD
Expected Performance of the ATLAS Experiment - Detector, Trigger and Physics
A detailed study is presented of the expected performance of the ATLAS
detector. The reconstruction of tracks, leptons, photons, missing energy and
jets is investigated, together with the performance of b-tagging and the
trigger. The physics potential for a variety of interesting physics processes,
within the Standard Model and beyond, is examined. The study comprises a series
of notes based on simulations of the detector and physics processes, with
particular emphasis given to the data expected from the first years of
operation of the LHC at CERN
The Closed-Cone Pines of the Northern Channel Islands
Our interest in the pines of the Northern Channel Islands developed in the course of our work with the California closed-cone pines. The focus of these investigations has been Monterey pine (Pinus radiata D. Don.), a species which is widely planted as a forest tree in New Zealand, Australia, Chile, South Africa, and Spain. Despite its wide use, P. radiata is not well known genetically and its performance in California, its native home, has not been fully assessed. The first phase of the project on Pinus radiata entailed study and sampling of the three native stands on the mainland. Later, we sampled its southern variety {P. radiata var. binata Engelm.) on Guadalupe Island. This led to a consideration of the other insular populations of closed-cone pines and their relationship to mainland P. radiata and Bishop pine (P. muricata D. Don.). We thus became aware of the confusion and uncertainty relative to the taxonomic and biosystematic relationships within the P. radiata-muricata complex. In the past, California has relied on virgin and second-growth forests as a source of timber. In the future, artificial regeneration will become of increasing importance, and hitherto unused species may gain status as prime wood and fiber producers. Most insular populations of closed-cone pines occur on sites marginal for good tree growth. If planted on better sites, they may prove to be economically valuable. Furthermore, it may be possible to combine their ability to survive on poor sites with the fast-growth characteristics of other species or populations to produce strains suitable for wood production in less-than-optimal situations. The hybrid Pinus attenuata X P. radiata is a good example of the above possibility, combining the drought and cold resistance of knob-cone pine (P. attenuata Lemmon) with the fast growth of P. radiata. Such economic considerations, in addition to the biosystematic problems cited above, led us to study and sample the closed-cone pine populations on Guadalupe Island in February 1963. Cedros Island in April 1963, Santa Cruz Island in June 1964. and Santa Rosa Island in April 1965. This paper contains descriptions of the populations of closed-cone pines on Santa Cruz and Santa Rosa islands, and analyses of data from specimens collected on these islands as well as related mainland populations of Pinus muricata. Our results and observations are then discussed in the light of present knowledge of the California closed-cone pines.Linhart, Y. B., B. Burr, and M. T. Conkle. "The Closed-Cone Pines of the Northern Channel Islands." In: 1st Symposium on the Biology of the California Islands. National Park Service, 1965. 151-177
Lipoprotein‐Associated Phospholipase A2 Activity Is a Marker of Risk But Not a Useful Target for Treatment in Patients With Stable Coronary Heart Disease
Background: We evaluated lipoprotein‐associated phospholipase A2 (Lp‐PLA2) activity in patients with stable coronary heart disease before and during treatment with darapladib, a selective Lp‐PLA2 inhibitor, in relation to outcomes and the effects of darapladib in the STABILITY trial. Methods and Results: Plasma Lp‐PLA2 activity was determined at baseline (n=14 500); at 1 month (n=13 709); serially (n=100) at 3, 6, and 18 months; and at the end of treatment. Adjusted Cox regression models evaluated associations between Lp‐PLA2 activity levels and outcomes. At baseline, the median Lp‐PLA2 level was 172.4 μmol/min per liter (interquartile range 143.1–204.2 μmol/min per liter). Comparing the highest and lowest Lp‐PLA2 quartile groups, the hazard ratios were 1.50 (95% CI 1.23–1.82) for the primary composite end point (cardiovascular death, myocardial infarction, or stroke), 1.95 (95% CI 1.29–2.93) for hospitalization for heart failure, 1.42 (1.07–1.89) for cardiovascular death, and 1.37 (1.03–1.81) for myocardial infarction after adjustment for baseline characteristics, standard laboratory variables, and other prognostic biomarkers. Treatment with darapladib led to a ≈65% persistent reduction in median Lp‐PLA2 activity. There were no associations between on‐treatment Lp‐PLA2 activity or changes of Lp‐PLA2 activity and outcomes, and there were no significant interactions between baseline and on‐treatment Lp‐PLA2 activity or changes in Lp‐PLA2 activity levels and the effects of darapladib on outcomes. Conclusions: Although high Lp‐PLA2 activity was associated with increased risk of cardiovascular events, pharmacological lowering of Lp‐PLA2 activity by ≈65% did not significantly reduce cardiovascular events in patients with stable coronary heart disease, regardless of the baseline level or the magnitude of change of Lp‐PLA2 activity
Targeted kinase inhibition relieves slowness and tremor in a Drosophila model of LRRK2 Parkinson’s disease
Disease models: A reflex reaction A simple reflex in flies can be used to test the effectiveness of therapies that slow neurodegeneration in Parkinson’s disease (PD). Christopher Elliott and colleagues at the University of York in the United Kingdom investigated the contraction of the proboscis muscle which mediates a taste behavior response and is regulated by a single dopaminergic neuron. Flies bearing particular mutations in the PD-associated gene leucine-rich repeat kinase 2 (LRRK2) in dopaminergic neurons lost their ability to feed on a sweet solution. This was due to the movement of the proboscis muscle becoming slower and stiffer, hallmark features of PD. The authors rescued the impaired reflex reaction by feeding the flies l-DOPA or LRRK2 inhibitors. These findings highlight the proboscis extension response as a useful tool to identify other PD-associated mutations and test potential therapeutic compounds
Understanding the Reasons Behind Defect Levels in Post-Copper-CMP Cleaning Processes with Different Chemistries and PVA Brushes
Results from a series of post-CMP PVA scrubbing marathon runs performed in a high-volume manufacturing fab are scientifically explained via a series of controlled laboratory tests. The major differences in the ingredients within the cleaning solutions, and some of the key physical properties of the brushes are identified and their effects on various critical factors are studied. These include the magnitude of shear forces present in the brush-solution-wafer interface, the water uptake and porosity of the brushes, the diffusivity of a given cleaning solution through the micro-pores and macro-pores of each type of brush, the open-circuit potential in a dynamic process, and the availability of the cleaning fluid between the brush nodules and the wafer surface. Results show a strong inverse correlation between wafer-level defects and shear force. The latter is shown to decrease with solution availability at the brush-wafer interface which in turn is shown to depend on brush porosity and the diffusion rate of the solution through the pores. Our understanding is further strengthened by dynamic electrochemical analysis data where we see a greater interfacial chemical activity (i.e., an increase in corrosion current) as solution availability is increased
- …
