1,737,839 research outputs found
Pentaminomycins A and B, Hydroxyarginine-Containing Cyclic Pentapeptides from <i>Streptomyces</i> sp. RK88-1441
No full textTwo new cyclic peptides, pentaminomycins
A (1) and
B (2), were isolated from cultures of Streptomyces sp. RK88-1441. Based on the interpretation of the NMR, UV, IR, and
MS data, the planar structures of 1 and 2 were elucidated as cyclic pentapeptides with a modified amino acid
residue, N5-hydroxyarginine (N5-OH-Arg).
The absolute configurations of the constituent amino acid residues
were determined by the advanced Marfey’s method. Localization
of l- and d-amino acids in the sequence was ascertained
by chiral analysis of the fragment peptide obtained from a partial
hydrolysate; amino acids were identified by LC-MS. Pentaminomycin
A (1) reduced α-MSH-stimulated melanin synthesis
by suppressing the expression of melanogenic enzymes including tyrosinase,
tyrosinase-related protein-1 (TRP-1), and tyrosinase-related protein-2
(TRP-2)
Comment on "Wandering minds: The default network and stimulus-independent thought"
No full textMason et al. (Reports, 19 January 2007, p. 393) attributed activity in certain regions of the "resting" brain to the occurrence of mind-wandering. However, previous research has demonstrated the difficulty of distinguishing this type of stimulus-independent thought from stimulus-oriented thought (e.g., watchfulness). Consideration of both possibilities is required to resolve this ambiguity
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Al-Li Alloy 1441 for Fuselage Applications
No full textA cooperative investigation was conducted to evaluate Al-Cu-Mg-Li alloy 1441 for long service life fuselage applications. Alloy 1441 is currently being used for fuselage applications on the Russian Be-103 amphibious aircraft, and is expected to be used for fuselage skin on a new Tupolev business class aircraft. Alloy 1441 is cold-rollable and has several attributes that make it attractive for fuselage skin applications. These attributes include lower density and higher specific modulus with similar strength as compared to conventional Al-Cu-Mg alloys. Cold-rolled 1441 Al-Li sheet specimens were tested at NASA Langley Research Center (LaRC) and at the All-Russia Institute of Aviation Materials (VIAM) in Russia to evaluate tensile properties, fracture toughness, impact resistance, fatigue life and fatigue crack growth rate. In addition, fuselage panels were fabricated by Tupolev Design Bureau (TDB) using 1441 skins and Al-Zn-Mg-Cu alloy stiffeners. The panels were subjected to cyclic pressurization fatigue tests at TDB and at LaRC to simulate fuselage pressurization/depressurization during aircraft service. This paper discusses the results from this investigation
Kajian atas Isbat awal Ramadhan 1441 Hijriyah
No full textSidang isbat adalah rapat musyawarah yang dilakukan untuk menentukan awal bulan hijriyah terutama awal Ramadhan, Syawal, dan Dzulhijjah dengan menggunakan rekapitulasi hasil hisab dan laporan rukyat dari Sabang hingga Merauke sebagai acuannya. Pada dasarnya isbat dilakukan untuk mengakomodir perbedaan dan memberikan kepastian kepada umat Islam terkait penentuan awal bulan hijriyah. Namun dalam kenyataannya tiap tahun terkadang masih saja terjadi perbedaan. Dalam anggota MABIMS masih ditemukan ketidaksesuaian antara teori dan realita di lapangan. Bukti kongkretnya dalam penentuan awal Ramadhan 1441 H. Berangkat dari persoalan tersebut, awal Ramadhan 1441 Hijriyah secara teori terjadi perbedaan. Padahal yang kita ketahui selama ini yang menjadi acuan sidang isbat adalah rekapitulasi hasil hisab yang berkembang dan laporan rukyat dari sabang sampai merauke. Inilah yang menjadi tantangan bagi pemerintah dalam isbat Awal Ramadhan 1441 Hijriyah dan hal ini penting untuk diteliti lebih lanjut. Berdasarkan latar belakang masalah tersebut, penulis merumuskan masalahnya. Bagaimana dasar isbat Pemerintah RI untuk Awal Ramadhan 1441 Hijriyah? Bagaimana analisis astronomis terkait isbat Awal Ramadhan 1441 Hijriyah?
Tujuan dari penelitian ini adalah untuk mengetahui dasar isbat yang digunakan pemerintah dalam isbat Awal Ramadhan 1441 Hijriyah dan mengetahui hasil kajian astronomis terkait isbat Awal Ramadhan 1441 Hijriyah. Penelitian ini menggunakan metode pendekatan kualitatif yang tergolong dalam jenis penelitian kepustakaan (library research). Penelitian ini mendeskripsikan mengenai kajian astronomis atas isbat awal Ramadhan 1441 Hijriyah. Dalam penelitian ini menggunakan Keputusan Menteri Agama Republik Indonesia Tentang Penetapan 1 Ramadhan 1441 H serta hasil wawancara dengan pakar astronomi dari Tim Falakiyah Kementerian Agama sebagai data primer. Adapun data sekundernya berupa buku-buku referensi maupun artikel, jurnal penelitian, modul, laporan penelitian serta media massa yang berkaitan dengan objek penelitian.
Berdasarkan hasil penelitian ini bahwa dasar isbat pemerintah dalam menentukan awal Ramadhan adalah hasil musyawarah antara peserta sidang yang dikukuhkan dan dilegitimasi oleh Keputusan Menteri Agama dengan data hisab dan laporan rukyatul hilal sebagai bahan pertimbangan. Ketetapan sidang isbat awal Ramadhan 1441 Hijriyah yang telah dikukuhkan dan dilegitimasi tersebut tercantum dalam Keputusan Menteri Agama Republik Indonesia Nomor 400 Tahun 2020 tentang penetapan 1 Ramadhan 1441 Hijriyah. Pelaksanaan sidang isbat pun mengacu pada fatwa MUI Nomor 2 Tahun 2004 yang menjelaskan bahwa penentuan awal bulan hijriyah akan diputuskan oleh Kementerian Agama RI melalui sidang isbat. Keberadaan sidang isbat juga diperkuat dengan adanya pasal 52A Undang-Undang Nomor 3 Tahun 2006 tentang Perubahan atas Undang-Undang Nomor 7 Tahun 1989 tentang Peradilan Agama. Kemudian secara astronomis, wilayah Indonesia hilal sudah berada di atas ufuk dan telah memenuhi kriteria MABIMS. Hasil rukyat pun dilaporkan ada dan telah sah disumpah kesaksiannya oleh Hakim Agama dan diterima sidang isbat. Jika dibandingkan dengan kriteria yang lain banyak yang belum imkan harus istikmal misal Rekomendasi Jakarta 2017 (tinggi hilal 3 derajat dan sudut elongasi 6,5 derajat), Limit Danjon (sudut elongasi 6,4 derajat) atau kriteria astronomis lainnya belum masuk. Tapi kriteria Wujudul Hilal (bulan terbenam setelah matahari terbenam) dan Rukyat Global sudah imkan. Yang harus dipertegas Indonesia memakai kriteria penentunya kriteria MABIMS 2-3 atau 8
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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