8,702 research outputs found
Анализ социальных медиа
The experimental electron-density distributions in crystals of five chain polymers [M(μ-X)2(py)2] (M = Zn, Cd; X = Cl, Br; py = 3,5-substituted pyridine) have been obtained from high-resolution X-ray diffraction data sets (sin θ/λ > 1.1 Å−1) at 100 K. Topological analyses following Bader's `Atoms in Molecules' approach not only confirmed the existence of (3, −1) critical points for the chemically reasonable and presumably strong covalent and coordinative bonds, but also for four different secondary interactions which are expected to play a role in stabilizing the polymeric structures which are unusual for Zn as the metal center. These weaker contacts comprise intra- and inter-strand C—H⋯X—M hydrogen bonds on the one hand and C—X⋯X—C interhalogen contacts on the other hand. According to the experimental electron-density studies, the non-classical hydrogen bonds are associated with higher electron density in the (3, −1) critical points than the halogen bonds and hence are the dominant interactions both with respect to intra- and inter-chain contacts
Two species? - Limits of the species concepts in the pygmy grasshoppers of the Tetrix bipunctata complex (Orthoptera, Tetrigidae)
Today, integrative taxonomy is often considered the gold standard when it comes to species recognition and delimitation. Using the Tetrix bipunctata complex, we here present a case where even integrative taxonomy may reach its limits. The Tetrix bipunctata complex consists of two morphs, bipunctata and kraussi, which are easily distinguished by a single character, the length of the hind wing. Both morphs are widely distributed in Europe and reported to occur over a large area in sympatry, where they occasionally may live also in syntopy. The pattern has led to disparate classifications, as on the one extreme, the morphs were treated merely as forms or subspecies of a single species, on the other, as separate species. For this paper, we re-visited the morphology by using multivariate ratio analysis (MRA) of 17 distance measurements, checked the distributional data based on verified specimens and examined micro-habitat use. We were able to confirm that hind wing length is, indeed, the only morphological difference between bipunctata and kraussi. We were also able to exclude a mere allometric scaling. The morphs are, furthermore, largely sympatrically distributed, with syntopy occurring regularly. However, a microhabitat niche difference can be observed. Ecological measurements in a shared habitat confirm that kraussi prefers a drier and hotter microhabitat, which possibly also explains the generally lower altitudinal distribution. Based on these results, we can exclude classification as subspecies, but the taxonomic classification as species remains unclear. Even with different approaches to classify the Tetrix bipunctata complex, this case is, therefore, not settled. We recommend continuing to record kraussi and bipunctata separately
ЯКІВ ДМИТРОВИЧ ГРАХОВ – ДІЯЧ КУЛЬТУРИ ТА ОСВІТИ В КАТЕРИНОСЛАВСЬКІЙ ГУБЕРНІЇ
Розглянуто життєвий шлях, освітянську, наукову та музеєзнавчу діяльність директора Катеринославської гімназії та училищ краю Якова Дмитровича Грахова в середині ХІХ ст.The article covers life, scientific and museum activities of Yakiv Dmitrovych Grakhov, a director of Katerinoslav schools in the middle of the 19th centuary
A new method for the spectroscopic identification of stellar non-radial pulsation modes. II. Mode identification of the Delta Scuti star FG Virginis
We present a mode identification based on new high-resolution time-series
spectra of the non-radially pulsating Delta Scuti star FG~Vir (HD 106384, V =
6.57, A5V). From 2002 February to June a global Delta Scuti Network (DSN)
campaign, utilizing high-resolution spectroscopy and simultaneous photometry
has been conducted for FG~Vir in order to provide a theoretical pulsation
model. In this campaign we have acquired 969 Echelle spectra covering 147 hours
at six observatories. The mode identification was carried out by analyzing line
profile variations by means of the Fourier parameter fit method, where the
observational Fourier parameters across the line are fitted with theoretical
values. This method is especially well suited for determining the azimuthal
order m of non-radial pulsation modes and thus complementary with the method of
Daszynska-Daszkiewicz (2002) which does best at identifying the degree l. 15
frequencies between 9.2 and 33.5 c/d were detected spectroscopically. We
determined the azimuthal order m of 12 modes and constrained their harmonic
degree l. Only modes of low degree (l <= 4) were detected, most of them having
axisymmetric character mainly due to the relatively low projected rotational
velocity of FG Vir. The detected non-axisymmetric modes have azimuthal orders
between -2 and 1. We derived an inclination of 19 degrees, which implies an
equatorial rotational rate of 66 km/s.Comment: 14 pages, 26 figure
Evolutionary implications of microplastics for soil biota
This is the author accepted manuscript. The final version is available from CSIRO Publishing via the DOI in this recordMicroplastic pollution is increasingly considered to be a factor of global change: in addition to aquatic ecosystems, this persistent contaminant is also found in terrestrial systems and soils. Microplastics have been chiefly examined in soils in terms of the presence and potential effects on soil biota. Given the persistence and widespread distribution of microplastics, it is also important to consider potential evolutionary implications of the presence of microplastics in soil; we offer such a perspective for soil microbiota. We discuss the range of selection pressures likely to act upon soil microbes, highlight approaches for the study of evolutionary responses to microplastics, and present the obstacles to be overcome. Pondering the evolutionary consequences of microplastics in soils can yield new insights into the effects of this group of pollutants, including establishing ‘true’ baselines in soil ecology, and understanding future responses of soil microbial populations and communities.MR acknowledges support from the ERC Advanced Grant ‘Gradual Change’ (694368).
UK received funding from the European Union's Horizon 2020 research and innovation
program under Marie Skłodowska-Curie grant agreement no. 751699
Re-use of spent cell culture medium in pilot scale and rapid preparative purification with membrane chromatography
Riese U, Lütkemeyer D, Heidemann R, Büntemeyer H, Lehmann J. Re-use of spent cell culture medium in pilot scale and rapid preparative purification with membrane chromatography. Journal of Biotechnology. 1994;34(3):247-257.Based on experiments in bench scale, a recycling of spent cell culture medium was performed in a 100-l pilot scale bioreactor. The cell cultivation has been done as a repeated batch procedure after the initial batch in the following four repeated batches spent medium from the previous batch was partially re-used. After microfiltration and ultrafiltration a part of the filtrate was mixed with a concentrate of amino acids and glucose, sterile filtered and subsequently filled back into the bioreactor. Up to 65% of the harvested cell- and product-free spent medium was re-used in each repeated batch. This procedure results in a saving of pure and waste water volume and saving of supplemented proteins as transferrin, insulin and lipoproteins and, therefore, also in a reduction of the production costs. A strongly acidic membrane ion exchanger was evaluated for the ability to purify the monoclonal antibodies from the pilot scale cultivation. Within minutes, gram quantities of product could be purified in a high flux system, especially developed for this purpose, achieving purities of 80%. The capacity of the acidic membrane ion exchanger was found in former investigations to be 1 mg cm -2 with recoveries up to 96%. Final purification was carried out by gel column filtration
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