1,080 research outputs found

    Strategi Belajar Aktif Tipe Everyone is a Teacher Here (Eth) Terhadap Hasil Belajar Siswa Kelas XI Ia Sman 5 Solok Selatan

    Full text link
    Rendahnya hasil belajar biologi siswa karena kurangnya pemahaman dan penguasaan materi pelajaran pada topik sistem koordinasi dan siswa cendrung pasif dan kurang berpartisipasi dalam belajar. Salah satu strategi yang dapat meningkatkan hasil belajar siswa adalah dengan strategi belajar aktif tipe Everyone is a Teacher Here (ETH). Penelitian ini merupakan penelitian eksperimen dengan rancangan penelitian Randomized Control Group Postest Only Design. Populasi dalam penelitian ini adalah seluruh siswa kelas XI IA SMAN 5 Solok Selatan. Sampel dalam penelitian ini adalah kelas XI IA1 sebagai kelas eksperimen dan kelas XI IA2 sebagai kelas kontrol. Tujuan dari penelitian ini adalah untuk mengetahui pengaruh strategi belajar aktif tipe Everyone is a Teacher Here (ETH) terhadap hasil belajar biologi siswa kelas XI IA SMAN 5 Solok Selatan. Hasil penelitian menunjukkan bahwa hasil belajar biologi siswa kelas eksperimen lebih tinggi daripada kelas kontrol. Hal ini dapat disimpulkan hasil belajar biologi siswa yang dalam pembelajarannya menggunakan strategi belajar aktif tipe Everyone is a Teacher Here lebih baik dibandingkan dengan pembelajaran konvensional

    New Caledonian crows afford invaluable comparative insights into human cumulative technological culture

    Get PDF
    The New Caledonian crow may be the only non-primate species exhibiting cumulative technological culture. Its foraging tools show clear signs of diversification and progressive refinement, and it seems likely that at least some tool-related information is passed across generations via social learning. Here, we explain how these remarkable birds can help us uncover the basic biological processes driving technological progress.PostprintPeer reviewe

    Optimum Slot Weld Width for Cold-Formed Steel

    Get PDF
    Slot welds can be used for connections in cold-formed steel (CFS) structures. However, structural engineers will find AISI S100, “North American Specification for the Design of Cold-Formed Steel Structural Members” (AISI 2016) - which can be used for guidance in calculating structural capacity of many welds types - silent on this specific application. Research at the University of Colorado Denver has been directed toward determination of the strength of slot welds in sheet steel. A comprehensive series of tests were performed to determine structural capacity and ductility of various slot weld widths using a metal inert gas (MIG) welding process. A slot weld connection between two pieces of sheet steel was designed, one with punched slots of various widths, and the other a blank piece to receive the weld. Weldability problems associated with slot welds of various widths on galvanized sheet steel were encountered. The testing program to investigate slot widths to address these concerns is reported upon. A program of monotonic tension tests was conducted. This testing program built on 1979 research by Pekoz and McGuire at Cornell University for fillet welds on lap joint specimens. While AISI is silent on slot weld design criteria, the authors found certain slot widths were more advantageous than others

    Identification of Unknown Contaminants in Water Samples from ISS Employing Liquid Chromatography/Mass Spectrometry/Mass Spectrometry

    Get PDF
    Mass Spectrometry/Mass Spectrometry (MS/MS) is a powerful technique for identifying unknown organic compounds. For non-volatile or thermally unstable unknowns dissolved in liquids, liquid chromatography/mass spectrometry/mass spectrometry (LC/MS/MS) is often the variety of MS/MS used for the identification. One type of LC/MS/MS that is rapidly becoming popular is time-of-flight (TOF) mass spectrometry. This technique is now in use at the Johnson Space Center for identification of unknown nonvolatile organics in water samples from the space program. An example of the successful identification of one unknown is reviewed in detail in this paper. The advantages of time-of-flight instrumentation are demonstrated through this example as well as the strategy employed in using time-of-flight data to identify unknowns

    Screw and Pin Fastener Tests for Cold-Formed Steel

    Get PDF
    Because of limited available information on strength and ease of installation of specific fasteners for a particular application to a steel deck diaphragm, a preliminary testing program comparing the shear strength of commercially available screws and gas-actuated shot pins was conducted by J. R. Harris and Company at the University of Colorado Denver in 2018. A test was designed to explore the behavior and capacity of various fasteners, securing two and three pieces of sheet steel of various thicknesses together. Specimens were fabricated and load tested, with the sheet steel pieces in tension, so the fasteners were subject to shear. Four fasteners, in two rows of two, were used for all tests, with different end distances also being studied. Most of the tests were monotonic tension, and those results were used to develop a cyclic testing protocol for the best performing screw and shot pin. Most limit states encountered were limited by tilting of the screw against the sheet steel in bearing, leading to a ductile failure. Fastener shear was encountered in a small percentage of cases. Results are compared to each other and to AISI calculated values

    Post-translational regulation of RORγt—A therapeutic target for the modulation of interleukin-17-mediated responses in autoimmune diseases

    Get PDF
    AbstractRetinoic acid-related orphan receptor gamma t (RORγt) is a nuclear receptor, which is selectively expressed by various lymphocytes. RORγt is critical for the development of secondary and tertiary lymphoid organs, and for the thymic development of the T cell lineage. RORγt has been extensively studied as the master transcription factor of IL-17 expression and Th17 cells, which are strongly associated with various inflammatory and autoimmune conditions. Given its essential role in promoting pro-inflammatory responses, it is not surprising that the expression of RORγt is tightly controlled. By its nature as a nuclear receptor, RORγt activity is also regulated in a ligand-dependent manner, which makes it an attractive drug target. In addition, multiple post-translational mechanisms, including post-translational modifications, such as acetylation and ubiquitinylation, as well as interactions with various co-factors, modulate RORγt function. Here we attempt a comprehensive review of the post-translational regulation of RORγt, an area that holds the potential to transform the way we target the RORγt/IL-17 pathway, by enabling the development of safe and highly selective modulators of RORγt activity

    Utilização do farelo de canola em rações para frangos de corte.

    Get PDF
    O que e farelo de canola?; O valor nutritivo do farelo de canola; Utilização do farelo de canola; Cuidados com o uso do farelo de canola.bitstream/item/59455/1/CUsersPiazzonDocuments4.pd

    Ion-Exclusion Chromatography for Analyzing Organics in Water

    Get PDF
    A liquid-chromatography technique has been developed for use in the quantitative analysis of urea (and of other nonvolatile organic compounds typically found with urea) dissolved in water. The technique involves the use of a column that contains an ion-exclusion resin; heretofore, this column has been sold for use in analyzing monosaccharides and food softeners, but not for analyzing water supplies. The prior technique commonly used to analyze water for urea content has been one of high-performance liquid chromatography (HPLC), with reliance on hydrophobic interactions between analytes in a water sample and long-chain alkyl groups bonded to an HPLC column. The prior technique has proven inadequate because of a strong tendency toward co-elution of urea with other compounds. Co-elution often causes the urea and other compounds to be crowded into a narrow region of the chromatogram (see left part of figure), thereby giving rise to low chromatographic resolution and misidentification of compounds. It is possible to quantitate urea or another analyte via ultraviolet- and visible-light absorbance measurements, but in order to perform such measurements, it is necessary to dilute the sample, causing a significant loss of sensitivity. The ion-exclusion resin used in the improved technique is sulfonated polystyrene in the calcium form. Whereas the alkyl-chain column used in the prior technique separates compounds on the basis of polarity only, the ion-exclusion-resin column used in the improved technique separates compounds on the basis of both molecular size and electric charge. As a result, the degree of separation is increased: instead of being crowded together into a single chromatographic peak only about 1 to 2 minutes wide as in the prior technique, the chromatographic peaks of different compounds are now separated from each other and spread out over a range about 33 minutes wide (see right part of figure), and the urea peak can readily be distinguished from the other peaks. Although the analysis takes more time in the improved technique, this disadvantage is offset by two important advantages: Sensitivity is increased. The minimum concentration of urea that can be measured is reduced (to between 1/5 and 1/3 of that of the prior technique) because it is not necessary to dilute the sample. The separation of peaks facilitates the identification and quantitation of the various compounds. The resolution of the compounds other than urea makes it possible to identify those compounds by use of mass spectrometry

    Potential energy surfaces of superheavy nuclei

    Get PDF
    We investigate the structure of the potential energy surfaces of the superheavy nuclei 258Fm, 264Hs, (Z=112,N=166), (Z=114,N=184), and (Z=120,N=172) within the framework of self-consistent nuclear models, i.e. the Skyrme-Hartree-Fock approach and the relativistic mean-field model. We compare results obtained with one representative parametrisation of each model which is successful in describing superheavy nuclei. We find systematic changes as compared to the potential energy surfaces of heavy nuclei in the uranium region: there is no sufficiently stable fission isomer any more, the importance of triaxial configurations to lower the first barrier fades away, and asymmetric fission paths compete down to rather small deformation. Comparing the two models, it turns out that the relativistic mean-field model gives generally smaller fission barriers.Comment: 8 pages RevTeX, 6 figure
    corecore