2,467 research outputs found
Finding Optimal-Path Maps for Path Planning Across Weighted Regions
This paper appeared in the International Journal of Robotics Research, 19, 2 (February 2000), pp. 83-95, with
elaborating additions from [Rowe and Alexander, 1997]. The equations were redone for greatly improved clarity in
2008.Optimal-path maps tell robots or people the best way to reach a goal point from anywhere in a known terrain area,
eliminating most of the need to plan during travel. We address the construction of optimal-path maps for twodimensional
polygonal weighted-region terrain, terrain partitioned into polygonal areas such that the cost per unit
distance traveled is homogeneous and isotropic within each polygon. This is useful for overland route planning across
varied ground surfaces and vegetation. We propose a new algorithm that recursively partitions terrain into regions of
similar optimal-path behavior, and defines corresponding "path subspaces" for these regions. This process constructs
a piecewise-smooth function of terrain position whose gradient direction is everywhere the optimal-path direction,
permitting quick finding of optimal paths. Our algorithm is more complicated than the current path-caching and
wavefront-propagation algorithms, but gives more accurate maps requiring less space to represent. Experiments with
an implementation confirm the practicality of our algorithm.This work was supported in part by the U.S. Army Combat Developments Experimentation Center under MIPR ATEC 88-86. This work was also prepared in part in conjunction with research conducted for the Naval Air Systems Command and funded by the Naval Postgraduate School.supported in part by the U.S. Army Combat Developments Experimentation Center under MIPR ATEC 88-86. This work was also prepared in part in conjunction with research conducted for the Naval Air Systems Command and funded by the Naval Postgraduate School.Approved for public release; distribution is unlimited
Endoscopic Ultrasound for the Treatment of Gastric Variceal Bleeding in a Patient with Portal Cavernoma
"A 30-year-old lady was admitted with two weeks of fever and right upper quadrant pain. She had a background of non-malignant, non-cirrhotic portal vein thrombosis (PVT) with cavernoma formation. There was no detected underlying pro-thrombotic condition. She had established portal hypertension with esophageal varices. Her portal cavernoma was complicated by portal biliopathy and concurrent gallstone disease - with an endoscopic retrograde cholangio-pancreatography (ERCP) and stenting four weeks prior to admission. Drug history included carvedilol for primary prophylaxis of bleeding, anticoagulation had not been undertaken due to collateralisation. Admission computerised tomography (CT) revealed multiple small liver abscesses with a patent biliary stent and no progression of PVT and she was treated conservatively with intravenous antibiotics."--Case summary and discussionAlexander Boyd (1, 2, 3), Brinder S Mahon (2), Neil Rajoriya (2, 3) ; 1. NIHR Birmingham Biomedical Research Centre, University Hospitals Birmingham NHS Foundation Trust and University of Birmingham. 2. University Hospitals Birmingham NHS Foundation Trust, Mindelsohn Way. 3. University of BirminghamIncludes bibliographical reference
Identifying Better Effective Higgsless Theories via W_L W_L Scattering
The three site Higgsless model has been offered as a benchmark for studying
the collider phenomenology of Higgsless models. In this talk, we present how
well the three site Higgsless model performs as a general representative of
Higgsless models in describing W_L W_L scattering, and which modifications can
make it more representative. We employ general sum rules relating the masses
and couplings of the Kaluza-Klein (KK) modes of the gauge fields in continuum
and deconstructed Higgsless models as a way to compare the different theories.
After comparing the three site Higgsless model to flat and warped continuum
Higgsless models, we analyze an extensions of the three site Higgsless model,
namely, the Hidden Local Symmetry (HLS) Higgsless model. We demonstrate that
W_LW_L scattering in the HLS Higgsless model can very closely approximate
scattering in the continuum models, provided that the parameter `a' is chosen
to mimic rho-meson dominance of pi-pi scattering in QCD
Synthesis, stereocontrol and structural studies of highly luminescent chiral tris-amidepyridyl-triazacyclononane lanthanide complexes
The configuration of the remote amide chiral moiety determines the helicity of the metal complex in Ln(III) complexes of nonadentate N6O3 ligands based on triazacyclononane. Solution NMR studies revealed the presence of a dominant isomer whose proportion varies from 9 : 1 to 4 : 1 from Ce to Yb and X-ray crystallographic studies at 120 K of the Yb and two enantiomeric Eu complexes confirmed the configuration as S-Δ-λ in the major isomer. Global minimisation methods allowed magnetic susceptibility and electronic relaxation times of the lanthanide ions to be estimated by analysis of variable field longitudinal relaxation rate (R1) data sets. A set of four europium complexes, containing different para-substituted pyridinyl-aryl groups, exist as one major isomer (15 : 1), and absorb light strongly via an ICT transition in the range 320 to 355 nm (ε = 55 to 65 000 M−1 cm−1). The two examples absorbing light at 332 nm, possess overall emission quantum yields of 35 and 37% in aerated water, making these systems as bright as any Eu complex in solution
Intra-session and inter-day reliability of the Myon 320 electromyography system during sub-maximal contractions
Electromyography systems are widely used within the field of scientific and clinical practices. The reliability of these systems are paramount when conducting research. The reliability of Myon 320 Surface Electromyography System is yet to be determined. This study aims to determine the intra-session and inter-day reliability of the Myon 320 Surface Electromyography System. Muscle activity from fifteen participants was measured at the anterior deltoid muscle during a bilateral front raise exercise, the vastus lateralis muscle during a squat exercise and the extensor carpi radialis brevis (ECRB) muscle during an isometric handgrip task. Intra-session and inter-day reliability was calculated by intraclass correlation coefficient, standard error of measurement and coefficient of variation (CV). The normalized root mean squared (RMS) surface electromyographic signals produced good intra-session and inter-day testing intraclass correlation coefficient values (range: 0.63-0.97) together with low standard error of measurement (range: 1.49-2.32) and CV (range: 95% Confidence Interval = 0.36-12.71) measures for the dynamic-and-isometric contractions. The findings indicate that the Myon 320 Surface Electromyography System produces good to fair reliability when examining intra-session and inter-day reliability. Findings of the study provide evidence of the reliability of electromyography between trials which is essential during clinical testing.</p
Modelling the West Nile virus force of infection in the European human population
West Nile virus (WNV) is among the most recent emerging mosquito-borne pathogens in Europe where each year hundreds of human cases are recorded. We developed a relatively simple technique to model the WNV force of infection (FOI) in the human population to assess its dependence on environmental and human demographic factors. To this aim, we collated WNV human case-based data reported to the European Surveillance System from 15 European Countries during the period 2010–2021. We modelled the regional WNV FOI for each year through normal distributions and calibrated the constituent parameters, namely average (peak timing), variance and overall intensity, to observed cases. Finally, we investigated through regression models how these parameters are associated to a set of climatic, environmental and human demographic covariates. Our modelling approach shows good agreement between expected and observed epidemiological curves. We found that FOI magnitude is positively associated with spring temperature and larger in more anthropogenic semi-natural areas, while FOI peak timing is negatively related to summer temperature. Unsurprisingly, FOI is estimated to be greater in regions with a larger fraction of elderly people, who are more likely to contract severe infections. Our results confirm that temperature plays a key role in shaping WNV transmission in Europe and provide some interesting hints on how human presence and demography might affect WNV burden. This simple yet reliable approach could be easily adopted for early warning and to address epidemiological investigations of other vector-borne diseases, especially where eco-epidemiological data are scarc
Reply to comment on the paper by Davies et al. “Resolving MISS conceptions and misconceptions: A geological approach to sedimentary surface textures generated by microbial and abiotic processes”
We thank Noffke (2017) for her comment and for providing an opportunity to clarify our classification of “sedimentary surface textures”. We accord great credit to Dr. Noffke and other dedicated researchers whose detailed work has brought microbially induced sedimentary structures (MISS) to the widespread attention of geoscientists. However, we stand by our assertion that attributing structures observed in practical field and laboratory studies to processes of formation is much more problematic than Noffke (2017) indicates. Indeed, points in the Comment confirm the need for a classification system that categorises the degree of certainty attributed to a given interpretation. We stress that our paper was not designed as a critique of previous studies of MISS but rather was designed to encourage a reasonable assessment of uncertainty in assigning sedimentary surface textures to physical processes or to MISS
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Overcoming myelosuppression due to synthetic lethal toxicity for FLT3-targeted acute myeloid leukemia therapy.
Activating mutations in FLT3 confer poor prognosis for individuals with acute myeloid leukemia (AML). Clinically active investigational FLT3 inhibitors can achieve complete remissions but their utility has been hampered by acquired resistance and myelosuppression attributed to a 'synthetic lethal toxicity' arising from simultaneous inhibition of FLT3 and KIT. We report a novel chemical strategy for selective FLT3 inhibition while avoiding KIT inhibition with the staurosporine analog, Star 27. Star 27 maintains potency against FLT3 in proliferation assays of FLT3-transformed cells compared with KIT-transformed cells, shows no toxicity towards normal human hematopoiesis at concentrations that inhibit primary FLT3-mutant AML blast growth, and is active against mutations that confer resistance to clinical inhibitors. As a more complete understanding of kinase networks emerges, it may be possible to define anti-targets such as KIT in the case of AML to allow improved kinase inhibitor design of clinical agents with enhanced efficacy and reduced toxicity
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