Tendo em vista que as questões históricas, políticas e sociais têm ocupado as páginas da produção literária guineense contemporânea, neste artigo, direcionamos a nossa investigação para uma análise ...das diferentes camadas de opressão sofridas pelas mulheres guineenses, a partir da leitura da obra Memórias SOMânticas (2016), do escritor guineense Abdulai Sila. Ao observar as dinâmicas que circulam na sociedade guineense contemporânea, verificamos que as situações de violência contra a mulher seguem um duplo direcionamento, seja pelas articulações coloniais e os atravessamentos ocidentais, seja pelas tradições culturais e as suas regras internas. Desse modo, percebe-se a necessidade de uma abordagem que reconheça esses elementos, explorando suas direções, experiências e pontos de vista, que apresentam um conhecimento mais detalhado da situação política de um determinado momento histórico, como também trata de questões mais particulares e subjetivas. Com esse intuito, retomaremos o discurso memorialístico da narradora, que percorrendo determinados caminhos afetivos, incorpora novos contributos e interrogações às narrativas contadas pela dita História oficial.
Penelitian ini adalah penelitian tindakan kelas yang terdiri dari empat langkah penelitian, yaitu perencanaan, tindakan, observasi, dan refleksi. Tujuan penelitian ini adalah untuk mengetahui bahwa ...penerapan variasi metode latihan berpasangan pada permainan sepaktakraw dapat meningkatkan kemampuan sepak sila siswa di kelas V SD Negeri 18 Kota Bengkulu. Adapun subjek penelitian ini berjumlah 25 siswa yang terdiri dari 15 jumlah siswa laki-laki dan 10 jumlah siswa perempuan. Instrumen yang digunakan dalam penelitian ini adalah lembar observasi aktivitas guru dan lembar observasi aktivitas siswa serta tes keterampilan siswa. Penelitian ini dilakukan dalam 2 siklus dan tes evaluasi siswa dilakukan di tiap-tiap akhir siklus. Hasil persentase observasi aktivitas siswa pada siklus 1 adalah 60%, siklus 2 adalah 86,67%. Persentase observasi aktivitas guru pada siklus 1 adalah 66,67% dan pada siklus 2 adalah 93,34%. Hasil rata-rata tes keterampilan pada siklus 1 adalah 17,72 dan pada siklus 2 yaitu 22,96 dengan standar ketuntasan 20 sepakan dalam waktu satu menit. Hasil penelitian ini menyatakan bahwa penggunaan variasi latihan berpasangan dapat meningkatkan kualitas pembelajaran sepak sila serta mampu menumbuhkan kegembiraan dan memotivasi siswa dalam belajar.Kata kunci : Sepak Sila, Variasi Latihan Berpasangan
A new 2,3‐disila‐1,3‐butadiene (3) was synthesized as pale yellow crystals by a double sila‐Peterson reaction of 1,1,2,2‐tetrasilyl‐1,2‐dilithiodisilane with two equivalents of 2‐adamantanone at 0 ...°C. In the solid state, the two SiC bonds adopt a synclinal conformation with a dihedral angle of 76.8(1)°. UV/Vis spectra show two distinct absorption bands, assignable to the π(SiC)→π*(SiC) transition, at 371 and 322 nm and the former is considerably redshifted compared with that of structurally similar silenes. The 2,3‐disilabutadiene isomerizes to the corresponding 1,3‐disilabicyclo1.1.0butane with the activation parameters of ΔH≠=74.5±5.4 kJ mol−1 and ΔS≠=−71.1±17.1 J mol−1 K−1. DFT studies suggest that the isomerization proceeds through a conrotatory route rather than a disrotatory route. H2O and 9,10‐phenanthrenequinone added across each SiC bond in the 2,3‐disila‐1,3‐butadiene. The UV/Vis spectrum and reactivity of 3 suggest that the interaction between the two SiC bonds in 3 would be significant but rather small compared with that between SiSi bonds in a synclinal tetrasilabutadiene.
A new 2,3‐disila‐1,3‐butadiene was synthesized as pale yellow crystals by a double sila‐Peterson reaction. Although the two SiC bonds adopt a synclinal conformation with a dihedral angle of 76.8(1)°, the redshifted longest absorption band maxima assignable to the π(SiC)→π*(SiC) transition at 371 nm suggests considerable interaction between two SiC bonds. The 2,3‐disila‐1,3‐butadiene is thermally unstable and isomerizes to 1,3‐disilabicyclo1.1.0butane (see scheme).
Pentacoordinate silicon derivatives with a chloromethyl ligand are versatile compounds that are usually obtained from the corresponding tetravalent trialkoxy- or trihalogeno(chloromethyl)silane. We ...describe herein the synthesis of a chloromethylsilicate bearing two Martin's ligands readily obtained by addition of in situ generated chloromethyllithium to a spirosilane. The reactivity of this new species was evaluated and it has been established that the chloride is displaced by strong nucleophiles such as alkyllithiums and (hetero)aryllithiums. In Lewis acidic conditions, the pentacoordinate silicon species rearranges through a formal insertion of a methylene into one Si-C bond, to form a new tetravalent spirosilane with a six-membered ring. The same kind of rearrangement can be triggered also by addition of a Lewis base. The mechanism of the rearrangement in both conditions has been studied by means of DFT calculations.
Synthesis of the bis‐spiroacetal core of 13‐desmethyl spirolide C has been completed based on a sila‐Stetter‐acetalization process. The acylsilane and enone partners in the Stetter reaction were ...prepared in 7 and 11 steps, respectively, from (S) and (R)‐aspartic acid. The quaternary center at C19 in the enone moiety was controlled by relying on the Seebach’s chiral self‐reproduction method using an enantiopure (S)‐lactic acid based dioxolanone. The final acid‐catalyzed spiroacetalization provided the desired spiroacetal as a mixture of diastereoisomers in 13 linear steps. Whatever the conditions used, the non‐natural transoid isomer was formed preferentially. However, both cisoid and transoid isomers were isolated pure and their structure assigned unambiguously through NMR spectroscopic studies.
Phycotoxins: Synthesis of the bis‐spiroacetal core of 13‐desmethyl spirolide C by using a sila‐Stetter‐acetalization cascade is described (see scheme; TBS = tert‐butyldimethylsilyl, TMS = trimethylsilyl). The acylsilane and enone fragments were prepared in 7 and 11 steps, respectively from (S)‐ and (R)‐aspartic acid. Spiroacetalization of the 1,4‐diketone was carried out under acidic conditions delivering the desired spiroacetal as a mixture of diastereoisomers in 18 % overall yield.
Generally the number of software and hardware components that need to communicate seamlessly with each other is fast increasing in the digital lab environment. Many of these systems are customized ...for a specific task or application, practically involving software development. Such software can range from simple pump controls to management systems, over SiLA 2 drivers for laboratory instruments. Once developed, this software needs to be installed and maintained on the desired hardware. In addition, managing the configuration of the software is equally important for successful use in the laboratory. In case of hardware problems or failure, reinstalling the software may become difficult if the information is lost. With this article, it is explained how this problem can be solved with an automated workflow and developed software, mkbox - a tool for creating reliable application-specific Linux images. The goal of mkbox is to create Linux images using simple description files. Images can be distributed to target devices in the laboratory by using the integrated update and deployment mechanism. Using the mkbox tool has simplified the development workflow in the lab environment and reduced the time required to maintain software on target devices.
Research on plant–animal interactions has been focused on direct consumer interactions (i.e. plants as resources), but non-trophic interactions including providing shelter or interference with ...movement can also affect the fine-scale distribution of animals. In particular, non-trophic interactions that are positive could support threatened animal populations. Positive interactions have been used in the restoration of plant communities, but have not yet been extended to the management of animal habitat. In this study, we tested the hypothesis that non-trophic interactions influence the occurrence of an endangered lizard species in an arid shrub-annual system. At a location known to have a population of blunt-nosed leopard lizards (Gambelia sila), we geotagged 700 shrubs, measured shrub morphometric traits, collected biomass samples, and surveyed for lizard presence using scat detection dogs over two years. Relative to 2014, in 2013 plant productivity was high and lizard scats were found more frequently in areas with low invasive grass cover (i.e. residual dry matter, RDM). In 2014, plant productivity was low because of an extreme drought year, and lizard scats were more frequently observed under shrub canopies, particularly those with relatively dense cover. These findings support the novel theory that positive non-trophic interactions are a critical form of plant–animal interactions in addition to consumption. Dominant shrubs can act as a foundation species by functioning as a basal node in structuring both plant and animal communities through a network of interactions. Managing dominant plants, in addition to habitat, is therefore important for conserving animal species in arid ecosystems.
Grain-size control on sediment composition is investigated in modern proximal sediment from the Sila Massif, where basic to felsic intrusive rocks are exposed in a Mediterranean humid–temperate ...upland climate. Samples were taken from small creeks and weathering profiles from three areas reflecting different bed rock compositions. Samples were separated into eleven grain size fractions from very coarse sand to clay and analyzed by (i) X-ray fluorescence for chemical composition and (ii) X-ray diffraction and Mineral Liberation Analysis for mineralogical composition. The chemical composition vs. grain size relations were modeled by compositional linear regression. Mineralogical composition of selected samples is used to substantiate the interpretations based on geochemistry.
reveal a high degree of chemical weathering with chemical index of alteration (CIA) up to 92. High CIA values are restricted to the fine-grained fractions, while sand-sized sediment average at low to moderate CIA values (~60). Although strongly weathered, the three sample suites reflecting basic to felsic plutonic bed rock can be effectively discriminated across all grain-size classes using trace elements such as V, Rb, and Sr. Linear trend modeling and mineralogical data reflect similar patterns for all sample suites implying similar processes independent of source rock composition. This includes overall decrease of quartz and K-feldspar over the full grain-size range from very coarse sand to clay, which is contrasted by overall increase of sheet silicates from coarse to fine. Among the latter, increase of clay minerals strongly outpaces the increase of micas in silt to clay fractions. A more complex behavior is shown by plagioclase, which is most abundant in intermediate grain-size fractions for all sample suites. This is likely caused by initial hydrolysis along cleavage and twinning planes and subsequent breakage of plagioclase crystals into smaller fragments. Towards finer grain size, intense hydrolysis has destroyed most feldspars.
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The application of a carbon-silicon bioisosteric replacement strategy to find new acaricides with improved properties led to the discovery of Sila-Cyflumetofen 6B, a novel and highly ...potent acaricide. The essential t-butyl group in the beta-ketonitrile acaricide Cyflumetofen 6A could be swapped with the bioisosteric trimethyl-silyl group with retention of high level acaricidal activity and favourable pharmacological properties. Sila-Cyflumetofen 6B was found to possess similar preferred energy-minimized conformation and electrostatic potential surface compare to Cyflumetofen 6A. Herein we also report the development and application of the first homology model of the spider mite mitochondrial electron transport complex II (succinate ubiquinone oxidoreductase; SQR) and demonstrated that the active metabolite AB-1 of Cyflumetofen 6A and its sila-analogue Sila-AB-1 bind to the Qp site in same binding pose and that both compounds form two H-bonds and a cation-π interaction with Trp 165, Tyr 433 and Arg 279, respectively. Furthermore, we also developed a new mode of action test for spider mite Complex II using cytochrome c as electron acceptor and blocking its re-oxidation by addition of KCN resulting in a sensitive and convenient colorimetric assay. This new method avoids the use of non-specific artificial electron acceptors and allows to measure SQR inhibition in crude extracts of Tetranychus urtice. In this assay Sila-AB-1, the intrinsically active metabolite of Sila-Cyflumetofen, 6A exhibited even a somewhat lower IC50 value than the metabolite of Cyflumetofen AB-1. Synthetic methodologies are described for the preparation of Sila-Cyflumetofen 6B and its active metabolite Sila-AB-1 which enable an efficient synthesis of these compounds in only 5 and 4 steps, respectively, from cheap commercial starting materials. Although the value of carbon-silicon bioisosteric replacements has already be demonstrated in the past it is to the best of our knowledge the first report of a successful application in crop protection research in the last two decades.
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