134 research outputs found
Optimization of Manufacturers Behaviour On the Basis of a Local Economic Agent-Based Model Implementation
In the era of globalization, local economic structures have not lost their significance and must be in the focus of a scientific research. Optimization problem solution could become a solid theoretical foundation for a local economic system effective functioning. To express an objective function in the analytical form in order to implement precise mathematical methods is impossible for a complex system, an economic system has proved to be such type system. Methods based on simulation are believed to be effective for finding solutions of a wide range of optimization problems. This paper details findings of the research aimed at solving optimization problem in terms of revealing optimal agent behavior in the course of exchanges in a local economic system on the basis of agent-based modeling usage. © 201
Determinants of Trust in B2C E-commerce and Their Relationship with Consumer Online Trust
UBVRI observations of the flickering of RS Ophiuchi at Quiescence
We report observations of the flickering variability of the recurrent nova RS
Oph at quiescence on the basis of simultaneous observations in 5 bands (UBVRI).
RS Oph has flickering source with (U-B)_0=-0.62 \pm 0.07, (B-V)_0=0.15 \pm
0.10, (V-R)_0=0.25 \pm 0.05. We find for the flickering source a temperature
T_fl = 9500 \pm 500 K, and luminosity L_fl = 50 - 150 L_sun (using a distance
of d=1.6kpc). We also find that on a (U-B) vs (B-V) diagram the flickering of
the symbiotic stars differs from that of the cataclysmic variables. The
possible source of the flickering is discussed. The data are available upon
request from the authors and on the web
www.astro.bas.bg/~rz/RSOph.UBVRI.2010.MNRAS.tar.gz.Comment: 7 pages, MNRAS (accepted
Structure and Magnetism of Neutral and Anionic Palladium Clusters
The properties of neutral and anionic Pd_N clusters were investigated with
spin-density-functional calculations. The ground state structures are
three-dimensional for N>3 and they are magnetic with a spin-triplet for 2<=N<=7
and a spin nonet for N=13 neutral clusters. Structural- and spin-isomers were
determined and an anomalous increase of the magnetic moment with temperature is
predicted for a Pd_7 ensemble. Vertical electron detachment and ionization
energies were calculated and the former agree well with measured values for
anionic Pd_N clusters.Comment: 5 pages, 3 figures, fig. 2 in color, accepted to Phys. Rev. Lett.
(2001
Postnatal cerebellar development in a mouse
The cerebellum is a part of the central nervous system, which plays an important role in cognitive functions, discriminative sensibility, and the coordination of voluntary movements. Its development takes place in two stages: prenatal and postnatal. The cerebellar germ originates from the rhombic lip. There are two major groups of cells: glutamatergic and GABAergic neurons, which are generated at different spatial-temporal intervals. In the postnatal period, Purkinje cells and their synaptic contacts undergo the most significant development. Another key point is the formation of anchoring centers and the foliation of the brain.The cerebellum is a part of the central nervous system, which plays an important role in cognitive functions, discriminative sensibility, and the coordination of voluntary movements. Its development takes place in two stages: prenatal and postnatal. The cerebellar germ originates from the rhombic lip. There are two major groups of cells: glutamatergic and GABAergic neurons, which are generated at different spatial-temporal intervals. In the postnatal period, Purkinje cells and their synaptic contacts undergo the most significant development. Another key point is the formation of anchoring centers and the foliation of the brain
Potent inhibitors active against HIV reverse transcriptase with K101P, a mutation conferring rilpivirine resistance
Catechol diether compounds have nanomolar antiviral and enzymatic activity against HIV with reverse transcriptase (RT) variants containing K101P, a mutation that confers high-level resistance to FDA-approved non-nucleoside inhibitors efavirenz and rilpivirine. Kinetic data suggests that RT (K101P) variants are as catalytically fit as wild-type and thus can potentially increase in the viral population as more antiviral regimens include efavirenz or rilpivirine. Comparison of wild-type structures and a new crystal structure of RT (K101P) in complex with a leading compound confirms that the K101P mutation is not a liability for the catechol diethers while suggesting that key interactions are lost with efavirenz and rilpivirine.Fil: Gray, William T.. University of Yale; Estados UnidosFil: Frey, Kathleen M.. University of Yale; Estados UnidosFil: Laskey, Sarah B.. University Johns Hopkins; Estados UnidosFil: Mislak, Andrea C.. University of Yale; Estados UnidosFil: Spasov, Krasimir A.. University of Yale; Estados UnidosFil: Lee, Won Gil. University of Yale; Estados UnidosFil: Bollini, Mariela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. University of Yale; Estados UnidosFil: Siliciano, Robert F.. University Johns Hopkins; Estados Unidos. Howard Hughes Medial Institute; Estados UnidosFil: Jorgensen, William L.. University of Yale; Estados UnidosFil: Anderson, Karen S.. University of Yale; Estados Unido
The role of P2 receptor-mediated component in neurogenic tone control of human great saphenous vein
© 2017, Nizhny Novgorod State Medical Academy. All rights reserved.The aim of the investigation was to evaluate experimentally the role of the P2 receptor-mediated component in neurogenic tone control of human varicose-affected and healthy great saphenous vein (GSV). Materials and Methods. The material for the study were segments of GSV obtained from two groups of patients: group 1 (n=14) included patients with varicose vein disease, in whom GSV was removed during surgical treatment; group 2 (n=21) comprised patients with coronary artery disease who underwent coronary artery bypass grafting using GSV as an autograft. Mechanical activity of the isolated veins was studied in vitro by electrical stimulation before and after incubation with atropine and phentolamine, pyridoxal-phosphate-6-azophenyl- 2’,4’-disulfonate (PPADS) and suramin (both nonselective antagonists of P2 receptors), and also after desensitization of P2X receptors by a,ß-methylene ATP. Results. Atropine and phentolamine did not completely inhibit the contractile responses evoked by electric field stimulation of the varicose and non-varicose GSV. PPADS (10 and 30 µM) and suramin (100 and 300 µM) significantly reduced the contractile amplitude of GSV response in both groups of veins (p0.05). Atropine, phentolamine and PPADS inhibited the contractile responses to a lesser extent in the varicose-affected veins compared to the veins unaffected by varicose disease. Conclusion. These experimental results suggest the presence of the P2 receptor-mediated component in the neurogenic control of human GSV tone. Further studies of the P2 receptor mechanism of action is promising for the development of drugs both for treating varicose veins and for preventing spasm of the venous grafts after aortocoronary bypass surgery
Density functional study of Au (n=2-20) clusters: lowest-energy structures and electronic properties
We have investigated the lowest-energy structures and electronic properties
of the Au(n=2-20) clusters based on density functional theory (DFT) with
local density approximation. The small Au clusters adopt planar structures
up to n=6. Tabular cage structures are preferred in the range of n=10-14 and a
structural transition from tabular cage-like structure to compact
near-spherical structure is found around n=15. The most stable configurations
obtained for Au and Au clusters are amorphous instead of
icosahedral or fcc-like, while the electronic density of states sensitively
depend on the cluster geometry. Dramatic odd-even alternative behaviors are
obtained in the relative stability, HOMO-LUMO gaps and ionization potentials of
gold clusters. The size evolution of electronic properties is discussed and the
theoretical ionization potentials of Au clusters compare well with
experiments.Comment: 6 pages, 7 figure
OptiJ: Open-source optical projection tomography of large organ samples
The three-dimensional imaging of mesoscopic samples with Optical Projection Tomography (OPT) has become a powerful tool for biomedical phenotyping studies. OPT uses visible light to visualize the 3D morphology of large transparent samples. To enable a wider application of OPT, we present OptiJ, a low-cost, fully open-source OPT system capable of imaging large transparent specimens up to 13 mm tall and 8 mm deep with 50 µm resolution. OptiJ is based on off-the-shelf, easy-to-assemble optical components and an ImageJ plugin library for OPT data reconstruction. The software includes novel correction routines for uneven illumination and sample jitter in addition to CPU/GPU accelerated reconstruction for large datasets. We demonstrate the use of OptiJ to image and reconstruct cleared lung lobes from adult mice. We provide a detailed set of instructions to set up and use the OptiJ framework. Our hardware and software design are modular and easy to implement, allowing for further open microscopy developments for imaging large organ samples
Initial Upper Palaeolithic humans in Europe had recent Neanderthal ancestry
Modern humans appeared in Europe by at least 45,000 years ago1–5, but the extent of their interactions with Neanderthals, who disappeared by about 40,000 years ago6, and their relationship to the broader expansion of modern humans outside Africa are poorly understood. Here we present genome-wide data from three individuals dated to between 45,930 and 42,580 years ago from Bacho Kiro Cave, Bulgaria1,2. They are the earliest Late Pleistocene modern humans known to have been recovered in Europe so far, and were found in association with an Initial Upper Palaeolithic artefact assemblage. Unlike two previously studied individuals of similar ages from Romania7 and Siberia8 who did not contribute detectably to later populations, these individuals are more closely related to present-day and ancient populations in East Asia and the Americas than to later west Eurasian populations. This indicates that they belonged to a modern human migration into Europe that was not previously known from the genetic record, and provides evidence that there was at least some continuity between the earliest modern humans in Europe and later people in Eurasia. Moreover, we find that all three individuals had Neanderthal ancestors a few generations back in their family history, confirming that the first European modern humans mixed with Neanderthals and suggesting that such mixing could have been common
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