436 research outputs found

    Low-Resolution Spectrum of the Diffuse Galactic Light and 3.3 um PAH emission with AKARI InfraRed Camera

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    We first obtained the spectrum of the diffuse Galactic light (DGL) at general interstellar space in 1.8-5.3 um wavelength region with the low-resolution prism spectroscopy mode of the AKARI Infra-Red Camera (IRC) NIR channel. The 3.3 um PAH band is detected in the DGL spectrum at Galactic latitude |b| < 15 deg, and its correlations with the Galactic dust and gas are confirmed. The correlation between the 3.3 um PAH band and the thermal emission from the Galactic dust is expressed not by a simple linear correlation but by a relation with extinction. Using this correlation, the spectral shape of DGL at optically thin region (5 deg < |b| < 15 deg) was derived as a template spectrum. Assuming that the spectral shape of this template spectrum is uniform at any position, DGL spectrum can be estimated by scaling this template spectrum using the correlation between the 3.3 um PAH band and the thermal emission from the Galactic dust.Comment: 7 pages, 5 figures, accepted by Publications of the Astronomical Society of Japan (PASJ

    Correction to: ‘Violence in the prehistoric period of Japan: the spatio-temporal pattern of skeletal evidence for violence in the Jomon period’

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    Whether man is predisposed to lethal violence, ranging from homicide to warfare, and how that may have impacted human evolution, are among the most controversial topics of debate on human evolution. Although recent studies on the evolution of warfare have been based on various archaeological and ethnographic data, they have reported mixed results: it is unclear whether or notwarfare among prehistoric hunter–gathererswas common enough to be a component of human nature and a selective pressure for the evolution of human behaviour. This paper reports the mortality attributable to violence, and the spatio-temporal pattern of violence thus shown among ancient hunter–gatherers using skeletal evidence in prehistoric Japan (the Jomon period: 13 000 cal BC–800 cal BC). Our results suggest that the mortality due to violence was low and spatio-temporally highly restricted in the Jomon period, which implies that violence including warfare in prehistoric Japan was not common

    Violence and warfare in prehistoric Japan

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    The origins and consequences of warfare or largescale intergroup violence have been subject of long debate. Based on exhaustive surveys of skeletal remains for prehistoric hunter-gatherers and agriculturists in Japan, the present study examines levels of inferred violence and their implications for two different evolutionary models, i.e., parochial altruism model and subsistence model. The former assumes that frequent warfare played an important role in the evolution of altruism and the latter sees warfare as promoted by social changes induced by agriculture. Our results are inconsistent with the parochial altruism model but consistent with the subsistence model, although the mortality values attributable to violence between hunter-gatherers and agriculturists were comparable

    Synthesis and conformational studies of chiral macrocyclic [1.1.1]metacyclophanes containing benzofuran rings

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    Macrocyclic [1.1.1]metacyclophanes (MCPs) containing benzene and benzofuran rings linked by methylene bridges and which can be viewed as calixarene analogues, have been synthesized by demethylation of [3.3.1]MCP-diones with trimethylsilyl iodide (TMSI) in MeCN. The [3.3.1]MCP-diones are synthesized by using (p-tolylsulfonyl)methyl isocyanide (TosMIC) as the cyclization reagent in N,N-dimethylformamide (DMF) with an excess of sodium hydride. ¹H NMR spectroscopy revealed that the remaining hydroxyl group on the phenyl ring is involved in intramolecular hydrogen bonding with the oxygen of one of the benzofuran rings. O-Methylation at the lower rim of monohydroxy[1.1.1]MCP in the presence of K₂CO₃ in acetone afforded a novel and inherently chiral calixarene analogue, namely the macrocyclic [1.1.1]MCP, possessing C₁ symmetry. The inherent chirality of the two conformers was characterized by ¹H NMR spectroscopy by addition of an excess of Pirkle's chiral shift reagent, which caused a splitting of the corresponding methylene protons to AB patterns. Single crystal X-ray analysis revealed the adoptation of a hemisphere-shaped cone isomer. DFT calculations were carried out to investigate the energy-minimized structures and the hydrogen bonds of the synthesized MCPs

    Synthesis and conformations of [2.n]metacyclophan-1-ene epoxides and their conversion to [n.1]metacyclophanes

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    A series of syn- and anti-[2.n]metacyclophan-1-enes have been prepared in good yields by McMurry cyclizations of 1,n-bis(5-tert-butyl-3-formyl-2-methoxyphenyl)alkanes. Significantly, acid catalyzed rearrangements of [2.n]metacyclophan-1-enes afforded [n.1]metacyclophanes in good yield. The ratios of the products are strongly regulated by the number of methylene bridges present. The percentages of the rearrangement products increase with increasing length of the carbon bridges. Characterization and the conformational studies of these products are described. Single crystal X-ray analysis revealed the adoption of syn- and anti-conformations. DFT calculations were carried out to estimate the energy-minimized structures of the synthesized metacyclophanes

    Synthesis and Structure of 1,2-Dimethylene[2.10]metacyclophane and Its Conversion into Chiral [10]Benzenometacyclophanes: Synthesis and Structure of 1,2-Dimethylene[2.10]metacyclophane and Its Conversion into Chiral [10]Benzenometacyclophanes

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    Bromination of 5,21-di-tert-butyl-8,24-dimethoxy-1,2-dimethyl[2.10]metacyclophan-1-ene (MCP-1-ene; 1) with benzyltrimethylammonium tribromide exclusively afforded 1,2-bis(bromomethyl)-5,21-di-tert-butyl-8,24-dimethoxy[2.10]MCP-1-ene (2). Debromination of 2 with Zn and AcOH in CH₂Cl solution at room temperature for 24 h produced dimethylene[2.10]MCP 7 in 92 % yield, which is a stable solid compound. Compound 7 was treated with dimethyl acetylenedicarboxylate (DMAD) to provide 1,2-(3′,6′-dihydrobenzo)-5,21-di-tert-butyl-8,24-dimethoxy[2.10]MCP-4′,5′-dimethylcarboxylate (8) in good yield. Diels–Alder adduct 8 was converted into a novel and inherently chiral areno-bridged dimethoxy[2.10]MCP-4′,5′-dimethylcarboxylate 9, possessing C₁ symmetry, by aromatization with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). A new type of N-phenyl-maleimide substituted 1,2-(3′,6′-dihydrobenzo)-5,21-di-tert-butyl-8,24-dimethoxy[2.10]MCP-4′,5′-N-phenylmaleimide 10 was also synthesized from 7 through treatment with N-phenylmaleimide in toluene at 110 °C followed by aromatization with DDQ. Single-crystal X-ray analysis of 9 revealed the formation of a syn-isomer

    Synthesis, structures and conformational studies of 1,2-dimethyl[2.10]metacyclophane-1-enes

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    A series of 1,2-dimethyl[2.10]metacyclophan-1-enes (MCP-1-enes) containing different substituent groups has been synthesized to illustrate their conformational behavior. 4,22-dimethoxy-1,2-dimethyl[2.10]MCP-1-ene 3 was synthesized by a Grignard coupling reaction, Friedel-Crafts acylation reactions and McMurry coupling reaction from 1,10-dibromodecane. The formation of 4,22-dihydroxy-1,2-dimethyl[2.10]MCP-1-ene 4 was carried out by demethylation of compound 3 with boron tribromide at room temperature. The syn type conformation of 4 was characterized by X-ray diffraction and was found to form both intramolecular and intermolecular hydrogen bonds between the two hydroxyl groups. From this reaction an interesting compound [10]tetrahydrobenzofuranophane 5 was afforded on prolonging the reaction time. 5,21-diformyl-4,22-dihydroxy-1,2-dimethyl[2.10]MCP-1-ene 6 has been prepared from 4,22-dihydroxy-1,2-dimethyl[2.10]MCP-1-ene 4 by using the Duff method in the presence of hexamethylenetetramine. Structural analysis by 1H NMR spectroscopy and X-ray diffraction confirmed that both the solution and the crystalline state of compound 6 adopts an anti-conformation which forms an intramolecular hydrogen bond between the formyl group and the hydroxyl group, which is an interesting finding for long carbon chain MCP compounds
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