421 research outputs found
Clopidogrel: A Pharmacogenomic Perspective on its Use in Coronary Artery Disease
The thienopyridine antiplatelet agent clopidogrel is an effective drug for the prevention of vascular events. However, data has accumulated over time to suggest it is prone to significant interpatient variability. While there are several factors that contribute to this, one of the most important is variability in forming the active metabolite necessary for clopidogrel function. Several enzymes are involved in formation of this metabolite, and two, CYP2C19 and P-glycoprotein, appear to have alleles that both occur frequently in the population and have a clinically significant impact. Patients carrying these alleles can be identified, but it remains to be determined if this information is necessary or sufficient for risk stratification. Furthermore, if patients with high-risk alleles are identified, it is unclear how treatment should be adjusted
The Neural Control of a Robot in the Conditions of Movable Obstacles
The proposed concept of robot control assisting uses a neural network, whose operation relies on the activation of neurons delimiting a path from the source to the target with evading movable obstacles The complexity of the control algorithm is O (n). The proposed adjustment of neuron sensitivity using a two-element pencils of planes passing over the shortest path of the robot makes it possible to obtain a set of solutions with simultaneous classification in terms of a very important path length criterion.Предложена концепция сопровождения управления роботом с использованием нейронной сети, работа которой основана на активизации нейронов, определяющих путь от исходной точки до цели с уклонением от подвижных препятствий. Сложность алгоритма управления составляет О (n). Предложенная настройка нейронной чувствительности с использованием двухэлементных пучков плоскостей, пересекающих кратчайший путь робота, позволяет получить множество решений с одновременной классификацией по критерию длины пути.Запропоновано концепцію супроводу управління роботом з використанням нейронної мережі, робота якої базується на активізації нейронів, що визначають шлях від вихідної точки до цілі з відхиленням від рухомих перешкод. Складність алгоритму управління складає On(). Запропоноване настроювання нейронної чутливості з використанням двоелементних пучків площин, що перетинають найкоротший шлях робота, дозволяє отримати велику кількість рішень з одночасною класифікацією за критерієм довжини шляху
Novel lactoferrin-loaded alginate microbeads display anti-Clostridium difficile defence properties
Serum trace metal concentrations in Clostridium difficile infection and their relationship to disease severity
The SUrvey for Pulsars and Extragalactic Radio Bursts V:Recent Discoveries and Full Timing Solutions
The SUrvey for Pulsars and Extragalactic Radio Bursts ran from 2014 April to
2019 August, covering a large fraction of the southern hemisphere at mid- to
high-galactic latitudes, and consisting of 9-minute pointings taken with the
20-cm multibeam receiver on the Parkes Radio Telescope. Data up to 2017
September 21 have been searched using standard Fourier techniques, single-pulse
searches, and Fast Folding Algorithm searches. We present 19 new discoveries,
bringing the total to 27 discoveries in the programme, and we report the
results of follow-up timing observations at Parkes for 26 of these pulsars,
including the millisecond pulsar PSR J1421-4409; the faint, highly-modulated,
slow pulsar PSR J1646-1910; and the nulling pulsar PSR J1337-4441. We present
new timing solutions for 23 pulsars, and we report flux densities, modulation
indices, and polarization properties.Comment: Accepted to MNRAS; data available at
https://doi.org/10.5281/zenodo.390098
Giant pulses from J1823-3021A observed with the MeerKAT telescope
The millisecond pulsar J1823-3021A is a very active giant pulse emitter in
the globular cluster NGC 6624. New observations with the MeerKAT radio
telescope have revealed 14350 giant pulses over 5 hours of integration time,
with an average wait time of about 1 second between giant pulses. The giant
pulses occur in phases compatible with the ordinary radio emission, follow a
power-law distribution with an index of -2.63 0.02 and contribute 4
percent of the total integrated flux. The spectral index of the giant pulses
follows a Gaussian distribution centered around -1.9 with a standard deviation
of 0.6 and is on average flatter than the integrated emission, which has a
spectral index of -2.81 0.02. The waiting times between the GPs are
accurately described by a Poissonian distribution, suggesting that the time of
occurrence of a GP is independent from the times of occurrence of other GPs. 76
GPs show multiple peaks within the same rotation, a rate that is also
compatible with the mutual independence of the GP times of occurrence. We
studied the polarization properties of the giant pulses finding, on average,
linear polarization only at the 1 percent level and circular polarization at
the 3 percent level, similar to the polarization percentages of the total
integrated emission. In 4 cases it was possible to measure the RM of the GPs
which are highly variable and, in two cases, is inconsistent with the mean RM
of the total integrated pulsar signal.Comment: Accepted for publication in MNRAS. 8 Pages, 11 Figure
The Thousand Pulsar Array program on MeerKAT – IX. The time-averaged properties of the observed pulsar population
We present the largest single survey to date of average profiles of radio pulsars, observed and processed using the same telescope and data reduction software. Specifically, we present measurements for 1170 pulsars, observed by the Thousand Pulsar Array programme at the 64-dish SARAO MeerKAT radio telescope, in a frequency band from 856 to 1712 MHz. We provide rotation measures (RM), dispersion measures, flux densities, and polarization properties. The catalogue includes 254 new RMs that substantially increase the total number of known pulsar RMs. Our integration times typically span over 1000 individual rotations per source. We show that the radio (pseudo-) luminosity has a strong, shallow dependence on the spin-down energy, proportional to Ė0.15±0.04, that contradicts some previous proposals of population synthesis studies. In addition, we find a significant correlation between the steepness of the observed flux density spectra and Ė, and correlations of the fractional linear polarization with Ė, the spectral index, and the pulse width, which we discuss in the context of what is known about pulsar radio emission and how pulsars evolve with time. On the whole, we do not see significant correlations with the estimated surface magnetic field strength, and the correlations with Ė are much stronger than those with the characteristic age. This finding lends support to the suggestion that magnetic dipole braking may not be the dominant factor for the evolution of pulsar rotation over the lifetimes of pulsars. A public data release of the high-fidelity time-averaged pulse profiles in full polarization accompanies our catalogue
The Green Bank Northern Celestial Cap Pulsar Survey II: The Discovery and Timing of Ten Pulsars
We present timing solutions for ten pulsars discovered in 350 MHz searches
with the Green Bank Telescope. Nine of these were discovered in the Green Bank
Northern Celestial Cap survey and one was discovered by students in the Pulsar
Search Collaboratory program in analysis of drift-scan data. Following
discovery and confirmation with the Green Bank Telescope, timing has yielded
phase-connected solutions with high precision measurements of rotational and
astrometric parameters. Eight of the pulsars are slow and isolated, including
PSR J09302301, a pulsar with nulling fraction lower limit of 30\% and
nulling timescale of seconds to minutes. This pulsar also shows evidence of
mode changing. The remaining two pulsars have undergone recycling, accreting
material from binary companions, resulting in higher spin frequencies. PSR
J05572948 is an isolated, 44 \rm{ms} pulsar that has been partially recycled
and is likely a former member of a binary system which was disrupted by a
second supernova. The paucity of such so-called `disrupted binary pulsars'
(DRPs) compared to double neutron star (DNS) binaries can be used to test
current evolutionary scenarios, especially the kicks imparted on the neutron
stars in the second supernova. There is some evidence that DRPs have larger
space velocities, which could explain their small numbers. PSR J1806+2819 is a
15 \rm{ms} pulsar in a 44 day orbit with a low mass white dwarf companion. We
did not detect the companion in archival optical data, indicating that it must
be older than 1200 Myr.Comment: 9 pages, 5 figure
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