Search results for "RAM"
showing 10 items of 35643 documents
Magic triangular and tetrahedral clusters
1997
Using the methods of density functional theory and the jellium model we show that clusters with triangular [in two dimensions (2D)] or tetrahedral [in three dimensions (3D)] shapes have a strong shell structure and enhanced stability. Moreover, the shell closings correspond to the lowest magic numbers of a 2D and 3D harmonic oscillator and at the same time to the number of divalent atoms in close-packed triangles and tetrahedrons. Ab initio molecular dynamics simulations for Na and Mg clusters support the results of the jellium model.
Dynamic Magnetic and Optical Insight into a High Performance Pentagonal Bipyramidal Dy(III) Single-Ion Magnet
2017
The pentagonal bipyramidal single-ion magnets (SIMs) are among the most attractive prototypes of high-performance single-molecule magnets (SMMs). Here, a fluorescence-active phosphine oxide ligand CyPh2PO (=cyclohexyl(diphenyl)phosphine oxide) was introduced into [Dy(CyPh2PO)2(H2O)5]Br3⋅2 (CyPh2PO)⋅EtOH⋅3 H2O, and combined dynamic magnetic measurement, optical characterization, ab initio calculation, and magneto-optical correlation of this high-performance pseudo-D5h DyIII SIM with large Ueff (508(2) K) and high magnetic hysteresis temperature (19 K) were performed. This work provides a deeper insight into the rational design of promising molecular magnets.
Machine learning of microbial interactions using abductive ILP and hypothesis frequency/compression estimation
2021
Interaction between species in microbial communities plays an important role in the functioning of all ecosystems, from cropland soils to human gut microbiota. Many statistical approaches have been proposed to infer these interactions from microbial abundance information. However, these statistical approaches have no general mechanisms for incorporating existing ecological knowledge in the inference process. We propose an Abductive/Inductive Logic Programming (A/ILP) framework to infer microbial interactions from microbial abundance data, by including logical descriptions of different types of interaction as background knowledge in the learning. This framework also includes a new mechanism …
Apprentissage automatique de réseaux d'interaction à partir de données de séquences de nouvelle génération
2022
Climate change and other human-induced processes are modifying ecosystems, globally, at an ever increasing rate. Microbial communities play an important role in the functioning ecosystems, maintaining their diversity and services. These communities are shaped by the different abiotic environmental effects to which they are subjected and the biotic interactions between all community members. The ANR Next-Generation Biomonitoring (NGB) project proposed to reconstruct interaction networks from abundance measures obtained sequencing environmental DNA (eDNA) and to use these networks to monitor ecosystem change. In this thesis, conducted as part of the NGB project, I evaluate the potential of tw…
Musical Competition Culture in 19th Century Italy. The Concorso Basevi (Florence) and the Circolo Bonamici (Naples)
2021
Musical competitions played an important function in Italian musical culture of the 19th century. Florence and Naples offer two interesting examples in this field. In the Tuscan city, Abramo Basevi (1818-1885) established an annual composition competition specially dedicated to chamber music, which reached great popularity throughout Europe; the “Concorso Basevi” took place six times starting from 1861. In Naples Ferdinando Bonamici (1827-1905) showed more varied interests and organized not only composition but also performance competitions between 1863 and 1865. Both experiences, based on individual or small group initiatives, were undoubtedly fragile, but they contributed significantly to…
A heuristic algorithm for project scheduling with splitting allowed
1996
In this article, we analyze the precedence diagramming method, the only published algorithm for time-only project scheduling with activity splitting allowed. The criteria used in this method (forward and backward pass computations) for deciding when an activity has to be interrupted are shown to be invalid in some situations. We look into the causes of these failures and propose new formulae that always provide feasible solutions. The new algorithm has been tested on 240 randomly generated problems ranging up to 600 activities and 7,200 precedence relationships, resulting in an average deviation from optima of less than 1 percent.
A parametric description of the 3D structure of the Galactic bar/bulge using the VVV survey
2017
We study the structure of the inner Milky Way using the latest data release of the Vista Variables in Via Lactea (VVV) survey. The VVV is a deep near-infrared, multi-colour photometric survey with a coverage of 300 square degrees towards the Bulge/Bar. We use Red Clump (RC) stars to produce a high-resolution dust map of the VVV's field of view. From de-reddened colour-magnitude diagrams we select Red Giant Branch stars to investigate their 3D density distribution within the central 4 kpc. We demonstrate that our best-fit parametric model of the Bulge density provides a good description of the VVV data, with a median percentage residual of 5$\%$ over the fitted region. The strongest of the o…
A Simple System Based on a Thiourea-Modified Fluorescein for ω-Amino Acid Discrimination
2015
A thiourea-modified fluorescein derivative was synthesized by reaction of fluorescein isothiocyanate with 2-(2-aminoethoxy)ethan-1-ol. UV/Vis absorption and fluorescence emission spectroscopy studies demonstrated that this heteroditopic receptor was able to discriminate among linear aliphatic ω-amino acids with different chain lengths.
Optimized In Silico Modeling of Drug Absorption after Gastric Bypass: The Case of Metformin
2021
Bariatric surgery is an effective treatment for severe obesity and related comorbidities, such as type II diabetes. Gastric bypass surgery shortens the length of the intestine, possibly leading to altered drug absorption. Metformin, a first-line treatment for type II diabetes, has permeability-dependent drug absorption, which may be sensitive to intestinal anatomic changes during bypass surgery, including Roux-en-Y gastric bypass (RYGB). Previous computer simulation data indicate increased metformin absorption after RYGB. In this study, we experimentally determined the region-dependent permeability of metformin, using the rat single-pass intestinal perfusion method (SPIP), which we then imp…
A five-coordinate manganese(iii) complex of a salen type ligand with a positive axial anisotropy parameter D.
2017
A new high-spin d4 roughly trigonal–bipyramidal (TBP) manganese(III) complex with a salen type ligand (H2L), namely MnL(NCS)·0.4H2O, has been synthesised and characterised by elemental analysis, ESI mass spectrometry, IR and UV-vis spectroscopy, and spectroelectrochemistry. X-ray diffraction analysis revealed an axial compression of the approximate TBP. Temperature dependent magnetic susceptibility and variable-temperature variable-field (VTVH) magnetisation measurements, as well as high-frequency and -field EPR (HFEPR) spectroscopy, were used to accurately describe the magnetic properties of this complex and, in particular, determine the spin Hamiltonian parameters: g-values and the zero-f…