3,944 research outputs found
Bioactive flavanones from Luma chequen
A bioassay-guided chemical study of a methanolic extract of fresh leaves of Luma chequen led to the isolation of lumaflavanones A (1), B (2) and C (3) whose structures are proposed on the basis of NMR spectroscopic data. The structure of lumaflavanone A was confirmed by X-ray analysis. Antifeedant (Spodoptera littoralis), brine shrimp (Artemia salina) and fungistatic (Botrytis cinerea) bioassays showed that while 3 was the most active in the first two assays the mixture of 1 and 2 was more effective as a fungistatic
Estimate of halo ellipticity as a function of radius with flexions
The cold dark matter theory predicts triaxial dark matter haloes. The radial
distribution of halo ellipticity depends on baryonic processes and the nature
of dark matter particles (collisionless or collisional). Here we show that we
can use lensing flexion ratios to measure the halo ellipticity as a function of
radius. We introduce a weight function and study the relationship between the
first and second order statistics of flexion ratios, both of which can be used
to reduce the bias in the estimate of ellipticity. we perform numerical tests
for our method, and demonstrate that it can reduce the bias and determine the
halo ellipticity as a function of radius. We also point out that the minimum
mean flexion ratio can be used to trace the centres of galaxy clusters.Comment: 9 pages,9 figures, MNRAS accepte
2-{3-Cyano-5,5-dimethyl-4-[4-(piperidin-1-yl)buta-1,3-dienyl]-2,5-dihydrofuran-2-ylidene}malononitrile
The title compound, C19H20N4O, crystallizes as twinned crystals containing two independent molecules which pack into a three-dimensional matrix via several C—H⋯N(cyano) interactions, with a C⋯N range of 3.324 (8)–3.568 (8) Å and C—H⋯N angles in the range 147–166°
Territorial and industry analysis of the fulfillment of Zaporizhian regional projects
The subject matter of the regional project in the context of regional and inter-regional influences has been determined. A comparative analysis of the economic potential of Dnieper economic region has been held. Characteristics and the purpose of major regional projects in Zaporizhzhya region have been established. Tendencies of the regional programs and projects use in the context of the fulfillment of the regional territory development strategy have been determined
2-Methyl-4,4-dioxo-N-phenyl-5,6-dihydro-1,4-oxathiine-3-carboxamide (Oxycarboxin)
In the title compound, C12H13NO4S, a systemic fungicide, the heterocycle adopts a lounge chair conformation and the dihedral angle between the ring planes is 25.8 (2)°. Intermolecular C—H⋯O hydrogen bonds are noted in the crystal structure. Also observed is a short interaction of a methylene hydrogen atom with the π-electron system of a phenyl ring in an adjacent molecule
Route persistence. Modelling and quantifying historical route-network stability from the Roman period to early-modern times (AD 100–1600):a case study from the Netherlands
Research on route-network stability is rare. In time, due to cultural and/or natural causes, settlement locations and route orientation shift. The nature of these spatial changes sheds light on the complex interaction between settlements and surrounding natural landscape conditions. This study investigates the stability of route networks in the Netherlands during the past two millennia by determining their persistence through time. Environmental, archaeological and historical data are used to reconstruct and compare route networks. By using network friction, archaeological data on settlement patterns and route networks in combination with historical data (e.g. old maps), we were able to model route-network persistence (not necessarily continuity) from the Roman to early medieval periods (AD 100–800) and from the Early Middle Ages to the Early Modern Times (AD 800–1600). Results show that around 67.6% of the modelled early-mediëval routes in the Netherlands are persistent with routes in the Roman period. Covering a much larger surface area of the Netherlands, 24.5% of the early-modern routes show a clear persistence with their early-medieval counterparts. Besides the differences in surface area, this downfall can largely be explained by cultural dynamics, with 71.4% of the earlymodern route network following modelled movement corridors. already in existence during the Early Middle Ages
catena-Poly[sodium(I)-μ-tetrabutoxyborato]
The title compound, [Na(C16H36BO4)]n, has a fourfold axis passing through the Na and B atoms which both are bound by four O atoms. The tetrabutoxyborate anion provides the bridging to form one-dimensional polymers running along [001], just like those found for the tetraethoxyborate structure. The two butoxy ‘tail’ atoms are disordered over two conformations in a 0.887 (9):0.113 (9) ratio
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