22,789 research outputs found

    Rapid chromosome territory relocation by nuclear motor activity in response to serum removal in primary human fibroblasts

    Get PDF
    This article has been made available through the Brunel Open Access Publishing Fund.Background: Radial chromosome positioning in interphase nuclei is nonrandom and can alter according to developmental, differentiation, proliferation, or disease status. However, it is not yet clear when and how chromosome repositioning is elicited. Results: By investigating the positioning of all human chromosomes in primary fibroblasts that have left the proliferative cell cycle, we have demonstrated that in cells made quiescent by reversible growth arrest, chromosome positioning is altered considerably. We found that with the removal of serum from the culture medium, chromosome repositioning took less than 15 minutes, required energy and was inhibited by drugs affecting the polymerization of myosin and actin. We also observed that when cells became quiescent, the nuclear distribution of nuclear myosin 1ß was dramatically different from that in proliferating cells. If we suppressed the expression of nuclear myosin 1ß by using RNA-interference procedures, the movement of chromosomes after 15 minutes in low serum was inhibited. When high serum was restored to the serum-starved cultures, chromosome repositioning was evident only after 24 to 36 hours, and this coincided with a return to a proliferating distribution of nuclear myosin 1ß. Conclusions: These findings demonstrate that genome organization in interphase nuclei is altered considerably when cells leave the proliferative cell cycle and that repositioning of chromosomes relies on efficient functioning of an active nuclear motor complex that contains nuclear myosin 1ß.Brunel Open Access Publishing Fun

    Water entry of a body which moves in more than six degrees of freedom

    Get PDF
    The water entry of a three-dimensional smooth body into initially calm water is examined. The body can move freely in its 6 d.f. and may also change its shape over time. During the early stage of penetration, the shape of the body is approximated by a surface of double curvature and the radii of curvature may vary over time. Hydrodynamic loads are calculated by the Wagner theory. It is shown that the water entry problem with arbitrary kinematics of the body motion, can be reduced to the vertical entry problem with a modified vertical displacement of the body and an elliptic region of contact between the liquid and the body surface. Low pressure occurrence is determined; this occurrence can precede the appearance of cavitation effects. Hydrodynamic forces are analysed for a rigid ellipsoid entering the water with 3 d.f. Experimental results with an oblique impact of elliptic paraboloid confirm the theoretical findings. The theoretical developments are detailed in this paper, while an application of the model is described in electronic supplementary materials

    Penerapan Strategi Quantum Writing Terhadap Kemampuan Menulis Buku Harian Pada Siswa

    Get PDF
    Belajar bahasa adalah belajar keterampilan. Pembelajaran bahasa Indonesia untuk meningkatkan keterampilan siswa dalam berbicara, membaca, mendengar dan menulis. Salah satu meteri dalam pelajaran bahasa Indonesia yang diajarkan di SMP kelas VII adalah menulis buku harian. Namun Kenyataan masih banyak siswa yang belum mampu menulis buku harian dengan baik dan benar. Berdasarkan permasalahan di atas penulis tertarik untuk mengkaji apakah ada perbedaan kemampuan menulis siswa yang diajarkan dengan strategi quantum writing dan yang diajarkan dengan pembelajaran konvensional pada materi menulis buku harian di kelas VII SMP Negeri 1 Peusangan. Penelitian ini merupakan penelitian kuntitatif dengan jenis penelitian eksperimen murni yang menjadi populasi dalam penelitian ini adalah seluruh siswa kelas VII SMP Negeri 1 Peusangan yang berjumlah 280 orang siswa, populasi ini sangat besar maka untuk menghemat waktu dan dana maka ditetapkan sampel penelitian ini dari jumlah populasi sehingga menjadi 65 siswa dari 2 kelas. Pengumpulan data dikumpulkan dengan tes soal sedangkan pengolahan data yang digunakan adalah data statistik uji-t dengan taraf signifikan α= 0,05. Dari hasil pengolahan data yang telah dilakukan di peroleh nilain thitung = 2,8 sedangkan ttabel = 1,67. dengan kata lain thitung > ttabel. berdasarkan hasil tersebut H0 ditolak dan Ha diterima, hal ini berarti kemampuan menulis siswa yang diajarkan dengan menggunakan strategi quantum writing lebih baik dari pada siswa yang diajarkan dengan pembelajaran konvensional.Kata Kunci: Strategi Quantum Writing dan Pembelajaran Konvensional PENDAHULUAN Belajar bahasa adalah belajar keterampilan. Pembelajaran bahasa Indonesia untuk meningkatkan keterampilan siswa dalam berbicara, membaca, mendengar dan menulis. Kelancaran berkomunikasi, maupun tulisan turut melengkapi suatu latar belakang pengalaman-pengalaman yang menguntungkan, serta keterampilan dalam proses belajar siswa. Belajar bahasa akan lebih bermakna jika metode pembelajaran yang diketahui dapat diaplikasikan sesuai dengan keterampilan yang dimiliki.Menulis buku harian adalah keterampilan siswa mengungkapkan gagasan, perasaan, pengalaman dalam bentuk catatan harian. Dalam pembelajaran metode ini, siswa diharapkan dapat menguasai indikator pembelajaran menulis buku harian yang telah ditetapkan dalam KTSP 2006 Kelasa VII SMP, yaitu mampu menulis pengalaman, pemikiran, dan perasaan dalam buku harian dengan memperhatikan cara pengungkapan dan tidak lupa menentukan waktu penulisan serta dengan penggunaan bahasa yang efektif. Siswa diharapkan terampil menulis buku harian sesuai dengan aspek penilaian yang kualitas isi, kelengkapan unsur buku harian, ejaan dan tanda baca, pilihan kata, keefetifan kalimat, kohesi dan koherensi, serta keterampilan menulis

    Pengajaran Bahasa Indonesia Melalui Cerita Tradisi Lisan

    Get PDF
    Penelitian ini akan membahas pengajaran bahasa Indonesia melalui cerita tradisi. Pembahasan utama dari makalah ini adalah daya tarik penggunaan cerita tradisi lisan bagi pembelajar asing dibandingkan dengan materi noncerita. Sisi penting dari makalah ini adalah upaya menjawab pertanyaan mengenai keunggulan dan kelemahan dalam menggunakan cerita tradisi lisan, dan tentang ketertarikan pembelajar asing atas cerita tradisional dibandingkan dengan pengajaran secara konvensional. Pertanyaan lain yang juga perlu dikupas di sini adalah apakah cerita tradisi lisan menempati posisi penting dalam pengajaran bahasa Indonesia atau merupakan pelengkap pengajaran saja. Perhatian pembelajar asing terhadap nilai-nilai budaya yang ada dalam cerita tradisi lisan tersebut juga akan dianalisis.Kata kunci: pengajaran bahasa Indonesia, pembelajaran asing dan cerita tradisi lisan. PENDAHULUANDalam penelitian ini pembahasan utama adalah daya tarik penggunaan cerita tradisi lisan bagi pembelajaran asing dibandingkan dengan materi noncerita. Tradisi lisan atau folklor lisan bisa berbentuk cerita, teka-teki, puisi rakyat, cerita prosa rakyat, dan nyanyian rakyat. Bentuk yang banyak digunakan adalah bentuk cerita dan label, misalnya centa Nyai Roro Kidul dan Si Kancil Yang Cerdik dan pemutaran video Belajar dari Borobudur. Latihan yang dilakukan adalah mengasah aspek kemahiran membaca, kosakata, tatabahasa, menyimak, diskusi, dan penyajian lisan (bercakap), serta, akhirnya, menulis.Telah diterbitkan berbagai macam buku pengajaran bahasa Indonesia. Antusiasme penerbit cukup besar untuk memenuhi kebutuhan pengajaran bahasa Indonesia, baik kebutuhan dasar pengajaran untuk anak-anak maupun untuk orang dewasa. Akan tetapi, dan sekian banyak buku-buku yang diterbitkan tidak terlalu banyak yang menggunakan centa tradisi lisan sebagai bahan pengajaran terutama untuk tingkat pemula.Di antara buku-buku terbitan Australia untuk tingkat madya yang menggunakan tradisi lisan adalah buku karangan McGarry and Sumaryono (1994) yang membawakan Cerila Kancil dan Cerita Ken Arok. Soewito Santosa dan Sumaryono (1979) membawakan cerita Sangkuriang dan Lorojonggrang. White (1989) dan Hibbs et.al (1998), masing-masing menggunakan cerita Nyai Roro Kidul dan Tangkuban Perahu, tetapi dalam bahasa Inggris. Hardie et.al (2001) menggunakan 4 cerita tradisi lisan dalam bahasa Indonesia, yaitu Dewi Sri, Dongeng Minangkabau, Si Kancil yang Cerdik dan, kemudian, sebagai aktivitas dalam kelas, pembelajar harus mendengarkan cerita Seekor Kura-Kura dan Dua Ekor Angsa

    Duplicated membrane estrogen receptors in the European sea bass (Dicentrarchus labrax): Phylogeny, expression and regulation throughout the reproductive cycle

    Get PDF
    The numerous estrogen functions reported across vertebrates have been classically explained by their binding to specific transcription factors, the nuclear estrogen receptors (ERs). Rapid non-genomic estrogenic responses have also been recently identified in vertebrates including fish, which can be mediated by membrane receptors such as the G protein-coupled estrogen receptor (Gper). In this study, two genes for Gper, namely gpera and gperb, were identified in the genome of a teleost fish, the European sea bass. Phylogenetic analysis indicated they were most likely retained after the 3R teleost-specific whole genome duplication and raises questions about their function in male and female sea bass. Gpera expression was mainly restricted to brain and pituitary in both sexes while gperb had a widespread tissue distribution with higher expression levels in gill filaments, kidney and head kidney. Both receptors were detected in the hypothalamus and pituitary of both sexes and significant changes in gpers expression were observed throughout the annual reproductive season. In female pituitaries, gpera showed an overall increase in expression throughout the reproductive season while gperb levels remained constant. In the hypothalamus, gpera had a higher expression during vitellogenesis and decreased in fish entering the ovary maturation and ovulation stage, while gperb expression increased at the final atresia stage. In males, gpers expression was constant in the hypothalamus and pituitary throughout the reproductive cycle apart from the mid- to late testicular development stage transition when a significant up-regulation of gpera occurred in the pituitary. The differential sex, seasonal and subtype-specific expression patterns detected for the two novel gper genes in sea bass suggests they may have acquired different and/or complementary roles in mediating estrogens actions in fish, namely on the neuroendocrine control of reproduction.info:eu-repo/semantics/publishedVersio

    Responsibilitas Jumlah Buah Per Malai Terhadap Ukuran Dan Kualitas Buah Mangga (Mangifera Indica L.) Varietas Arumanis

    Full text link
    Penelitian ini dimaksudkan untuk memperoleh jumlah buah per malai yang tepat untuk mempertahankan kualitas buah dengan produksi tinggi. Tujuan penelitian ini adalah untuk mempelajari pengaruh jumlah buah per malai terhadap produksi dan kualitas buah mangga. Penelitian dilaksanakan di kebun milik pribadi di Desa Maron, Kecamatan Patemon, Kabupaten Probolinggo pada tanggal 20 Juli sampai 24 Nopember 2000. Hasil penelitian menunjukkan bahwa jumlah buah per malai berpengaruh terhadap ukuran buah dan produksi, tetapi tidak berpengaruh terhadap kualitas buah mangga Arumanis. Perlakuan tiga buah per malai dapat meningkatkan produksi sebesar 36% dibandingkan dengan satu buah per malai dan 28% dibandingkan dengan dua buah per malainya

    Influence of leptin on arterial distensibility - A novel link between obesity and cardiovascular disease?

    Get PDF
    Background-The mechanisms by which obesity increases the risk of atherosclerotic cardiovascular disease (CVD) are poorly understood. In experimental models, leptin, a hormone produced by adipose tissue, has been shown adversely to affect vascular health. Therefore, we tested the hypothesis that high leptin concentrations are associated with lower arterial distensibility, an index of circulatory function relevant to the atherosclerotic process.Methods and Results-Noninvasive, high-resolution, vascular ultrasound was used to measure brachial artery distensibility in 294 healthy adolescents (aged 13 to 16 years) who had a broad range of body mass indexes. Fat mass was measured by bioelectric impedance analysis; fasting serum leptin concentration by radioimmunoassay; and lipid profile, fasting insulin, glucose, and C-reactive protein concentrations by standard laboratory techniques. Higher leptin concentrations were associated with impaired arterial distensibility (regression coefficient, -1.3% change in arterial distension per 10% increase in leptin; 95% CI, -1.9% to -0.8%; P<0.001). This association was independent of fat mass, blood pressure, and C-reactive protein, fasting insulin, or LDL cholesterol concentrations.Conclusions-Elevation in leptin was associated with impaired vascular function, independent of the metabolic and inflammatory disturbances associated with obesity. Our observations are consistent with data from experimental models and suggest that high leptin concentration is an important mechanism for the adverse influence of body fatness on CVD

    Temperature effects on zoeal morphometric traits and intraspecific variability in the hairy crab Cancer setosus across latitude

    No full text
    International audiencePhenotypic plasticity is an important but often ignored ability that enables organisms, within species-specific physiological limits, to respond to gradual or sudden extrinsic changes in their environment. In the marine realm, the early ontogeny of decapod crustaceans is among the best known examples to demonstrate a temperature-dependent phenotypic response. Here, we present morphometric results of larvae of the hairy crab , the embryonic development of which took place at different temperatures at two different sites (Antofagasta, 23°45′ S; Puerto Montt, 41°44′ S) along the Chilean Coast. Zoea I larvae from Puerto Montt were significantly larger than those from Antofagasta, when considering embryonic development at the same temperature. Larvae from Puerto Montt reared at 12 and 16°C did not differ morphometrically, but sizes of larvae from Antofagasta kept at 16 and 20°C did, being larger at the colder temperature. Zoea II larvae reared in Antofagasta at three temperatures (16, 20, and 24°C) showed the same pattern, with larger larvae at colder temperatures. Furthermore, larvae reared at 24°C, showed deformations, suggesting that 24°C, which coincides with temperatures found during strong EL Niño events, is indicative of the upper larval thermal tolerance limit.   is exposed to a wide temperature range across its distribution range of about 40° of latitude. Phenotypic plasticity in larval offspring does furthermore enable this species to locally respond to the inter-decadal warming induced by El Niño. Morphological plasticity in this species does support previously reported energetic trade-offs with temperature throughout early ontogeny of this species, indicating that plasticity may be a key to a species' success to occupy a wide distribution range and/or to thrive under highly variable habitat conditions
    • …
    corecore