8,058 research outputs found
The Light Lexicographic path Ordering
We introduce syntactic restrictions of the lexicographic path ordering to
obtain the Light Lexicographic Path Ordering. We show that the light
lexicographic path ordering leads to a characterisation of the functions
computable in space bounded by a polynomial in the size of the inputs
Racial/Ethnic Disparities in Diabetes Care and Outcomes: A Mixed Methods Study
Limited research has examined racial/ethnic differences in diabetes care and outcomes among primary care patients. This study examined racial/ethnic differences in diabetes care and outcomes among an ambulatory patient population and explored patient perceptions of the patient-provider relationship to inform strategies to improve care delivery. Using data from 62,149 adults with diabetes who received care within Atrium Health in 2013, regression models assessed associations between race/ethnicity and the following outcomes: glycated hemoglobin (HbA1c) tests, low density lipoprotein (LDL) and blood pressure (BP) screening, foot and eye exams, and HbA1c, LDL, and BP control. Eleven patients with diabetes and uncontrolled hypertension participated in three focus groups about their perceptions of the patient-provider relationship. Compared to non-Hispanic Whites, non-Hispanic Blacks had 22% to 73% higher odds of receiving screenings (HbA1c, LDL, BP, foot and eye exams;
Cervical Cancer-Associated Human Papillomavirus 16 E7 Oncoprotein Inhibits Induction of Anti-Cancer Immunity by a CD4+ T Cell Dependent Mechanism
Attempts to develop therapeutic vaccines against cervical cancer have been proven difficult. One of the major causes of the failure is due to the use of the wrong mouse models based on transplantable tumours in testing the efficacy of vaccines. Now that a transgenic epithelial mouse model has been developed to closely mimic cervical cancer, the mechanisms needed to eliminate this type of cancer could be studied. The E7 oncoprotein of Human Papillomavirus (HPV) is the most expressed HPV protein in cervical cancers and its continuous production is essential to maintain the cancerous state and therefore the obvious target in the development of vaccines. Skin grafts expressing the HPV 16 E7 protein (E7 autografts) are not spontaneously rejected from an MHC matched immunocompetent host. Interestingly, simultaneous placement of an MHC mismatched skin (allograft) next to an E7 autograft results in the E7 autograft rejection. However when the allograft also expresses E7, the E7 autograft is rejected more slowly. Autograft rejection requires CD8+ T cells, and is accelerated by removal of CD4+ T cells after placement of the E7 expressing allograft, suggesting induction of an E7 specific CD4+ regulatory T cell population by the E7 expressing allograft. This observation may have implications in designing effective vaccines and immunotherapy against cervical cancers in women
Magnetic Field Effects on the 1083 nm Atomic Line of Helium. Optical Pumping of Helium and Optical Polarisation Measurement in High Magnetic Field
The structure of the excited S and P triplet states of He
and He in an applied magnetic field B is studied using different
approximations of the atomic Hamiltonian. All optical transitions (line
positions and intensities) of the 1083 nm S-P transition are
computed as a function of B. The effect of metastability exchange collisions
between atoms in the ground state and in the S metastable state is
studied, and rate equations are derived, for the populations these states in
the general case of an isotopic mixture in an arbitrary field B. It is shown
that the usual spin-temperature description remains valid. A simple optical
pumping model based on these rate equations is used to study the B-dependence
of the population couplings which result from the exchange collisions. Simple
spectroscopy measurements are performed using a single-frequency laser diode on
the 1083 nm transition. The accuracy of frequency scans and of measurements of
transition intensities is studied. Systematic experimental verifications are
made for B=0 to 1.5 T. Optical pumping effects resulting from hyperfine
decoupling in high field are observed to be in good agreement with the
predictions of the simple model. Based on adequately chosen absorption
measurements at 1083 nm, a general optical method to measure the nuclear
polarisation of the atoms in the ground state in an arbitrary field is
described. It is demonstrated at 0.1 T, a field for which the usual
optical methods could not operate.Comment: 33 pages, 31 figures, 17 tables, 61 references. Revised version
(typos corrected, figure 11 replaced by the proper one) Accepted for
publication in EPJ
Lower and Middle Famennian (Upper Devonian) rugose corals from southern Belgium and northern France
After the late Frasnian extinctions, the rugose corals slowly recovered during the Lower and Middle Famennian (crepida to marginifera conodont zones) in southern Belgium and northern France (Avesnois) (Namur–Dinant Basin). Six genera represented by seven species are recognized and described here; one species (Breviphrentis superstes) is new. The rugose coral fauna described herein includes small solitary forms belonging to the so-called Cyathaxonia fauna and is similar or very close to those previously described within the same stratigraphic interval in Australia, China and Germany. It also contains a large species belonging to the genus Breviphrentis which was considered as extinct since the end of the Givetian (Middle Devonian) (“Lazarus taxon”). The tabulate corals from the Lower and Middle Famennian of this area, mainly represented by auloporids, are also briefly discussed. Rugosa only constituted a minor part of the fauna after the end-Frasnian crisis in the Namur–Dinant Basin contrary to the brachiopods, which were abundant and relatively diversified, and no rugose corals have been recovered from the early Lower Famennian (triangularis Zone). The first important Famennian coral radiation only took place during the Latest Famennian (Strunian)
Visualizing the logistic map with a microcontroller
The logistic map is one of the simplest nonlinear dynamical systems that
clearly exhibit the route to chaos. In this paper, we explored the evolution of
the logistic map using an open-source microcontroller connected to an array of
light emitting diodes (LEDs). We divided the one-dimensional interval
into ten equal parts, and associated and LED to each segment. Every time an
iteration took place a corresponding LED turned on indicating the value
returned by the logistic map. By changing some initial conditions of the
system, we observed the transition from order to chaos exhibited by the map.Comment: LaTeX, 6 pages, 3 figures, 1 listin
Online, interactive user guidance for high-dimensional, constrained motion planning
We consider the problem of planning a collision-free path for a
high-dimensional robot. Specifically, we suggest a planning framework where a
motion-planning algorithm can obtain guidance from a user. In contrast to
existing approaches that try to speed up planning by incorporating experiences
or demonstrations ahead of planning, we suggest to seek user guidance only when
the planner identifies that it ceases to make significant progress towards the
goal. Guidance is provided in the form of an intermediate configuration
, which is used to bias the planner to go through . We
demonstrate our approach for the case where the planning algorithm is
Multi-Heuristic A* (MHA*) and the robot is a 34-DOF humanoid. We show that our
approach allows to compute highly-constrained paths with little domain
knowledge. Without our approach, solving such problems requires
carefully-crafting domain-dependent heuristics
Poynting's theorem for planes waves at an interface: a scattering matrix approach
We apply the Poynting theorem to the scattering of monochromatic
electromagnetic planes waves with normal incidence to the interface of two
different media. We write this energy conservation theorem to introduce a
natural definition of the scattering matrix S. For the dielectric-dielectric
interface the balance equation lead us to the energy flux conservation which
express one of the properties of S: it is a unitary matrix. For the
dielectric-conductor interface the scattering matrix is no longer unitary due
to the presence of losses at the conductor. However, the dissipative term
appearing in the Poynting theorem can be interpreted as a single absorbing mode
at the conductor such that a whole S, satisfying flux conservation and
containing this absorbing mode, can be defined. This is a simplest version of a
model introduced in the current literature to describe losses in more complex
systems.Comment: 5 pages, 3 figures, submitted to Am. J. Phy
Stabilizing role of platelet P2Y(12) receptors in shear-dependent thrombus formation on ruptured plaques
Background: In most models of experimental thrombosis, healthy blood vessels are damaged. This results in the formation of a platelet thrombus that is stabilized by ADP signaling via P2Y(12) receptors. However, such models do not predict involvement of P2Y(12) in the clinically relevant situation of thrombosis upon rupture of atherosclerotic plaques. We investigated the role of P2Y(12) in thrombus formation on (collagen-containing) atherosclerotic plaques in vitro and in vivo, by using a novel mouse model of atherothrombosis.
Methodology: Plaques in the carotid arteries from Apoe(-/-) mice were acutely ruptured by ultrasound treatment, and the thrombotic process was monitored via intravital fluorescence microscopy. Thrombus formation in vitro was assessed in mouse and human blood perfused over collagen or plaque material under variable conditions of shear rate and coagulation. Effects of two reversible P2Y(12) blockers, ticagrelor (AZD6140) and cangrelor (AR-C69931MX), were investigated.
Principal Findings: Acute plaque rupture by ultrasound treatment provoked rapid formation of non-occlusive thrombi, which were smaller in size and unstable in the presence of P2Y(12) blockers. In vitro, when mouse or human blood was perfused over collagen or atherosclerotic plaque material, blockage or deficiency of P2Y(12) reduced the thrombi and increased embolization events. These P2Y(12) effects were present at shear rates >500 s(-1), and they persisted in the presence of coagulation. P2Y(12)-dependent thrombus stabilization was accompanied by increased fibrin(ogen) binding.
Conclusions/Significance: Platelet P2Y(12) receptors play a crucial role in the stabilization of thrombi formed on atherosclerotic plaques. This P2Y(12) function is restricted to high shear flow conditions, and is preserved in the presence of coagulation
Near Infrared Spectra of Type Ia Supernovae
We report near infrared (NIR) spectroscopic observations of twelve
``Branch-normal'' Type Ia supernovae (SNe Ia) which cover the wavelength region
from 0.8-2.5 microns. Our sample more than doubles the number of SNe Ia with
published NIR spectra within three weeks of maximum light. The epochs of
observation range from thirteen days before maximum light to eighteen days
after maximum light. A detailed model for a Type Ia supernovae is used to
identify spectral features. The Doppler shifts of lines are measured to obtain
the velocity and, thus, the radial distribution of elements.
The NIR is an extremely useful tool to probe the chemical structure in the
layers of SNe Ia ejecta. This wavelength region is optimal for examining
certain products of the SNe Ia explosion that may be blended or obscured in
other spectral regions. We identify spectral features from MgII, CaII, SiII,
FeII, CoII, NiII and possibly MnII. We find no indications for hydrogen, helium
or carbon in the spectra. The spectral features reveal important clues about
the physical characteristics of SNe Ia. We use the features to derive upper
limits for the amount of unburned matter, to identify the transition regions
from explosive carbon to oxygen burning and from partial to complete silicon
burning, and to estimate the level of mixing during and after the explosion.Comment: 44 pages, 7 figures, 3 tables, accepted by Ap
- …