1,050 research outputs found

    Application of advanced on-board processing concepts to future satellite communications systems

    Get PDF
    An initial definition of on-board processing requirements for an advanced satellite communications system to service domestic markets in the 1990's is presented. An exemplar system architecture with both RF on-board switching and demodulation/remodulation baseband processing was used to identify important issues related to system implementation, cost, and technology development

    The NAD(P)H oxidase homolog Nox4 modulates insulin-stimulated generation of H\u3csub\u3e2\u3c/sub\u3e0\u3csub\u3e2\u3c/sub\u3e and plays an integral role in insulin signal transduction

    Get PDF
    Insulin stimulation of target cells elicits a burst of H2O2 that enhances tyrosine phosphorylation of the insulin receptor and its cellular substrate proteins as well as distal signaling events in the insulin action cascade. The molecular mechanism coupling the insulin receptor with the cellular oxidant-generating apparatus has not been elucidated. Using reverse transcription-PCR and Northern blot analyses, we found that Nox4, a homolog of gp91phox, the phagocytic NAD(P)H oxidase catalytic subunit, is prominently expressed in insulin-sensitive adipose cells. Adenovirus-mediated expression of Nox4 deletion constructs lacking NAD(P)H or FAD/NAD(P)H cofactor binding domains acted in a dominant-negative fashion in differentiated 3T3-L1 adipocytes and attenuated insulin-stimulated H2O2 generation, insulin receptor (IR) and IRS-1 tyrosine phosphorylation, activation of downstream serine kinases, and glucose uptake. Transfection of specific small interfering RNA oligonucleotides reduced Nox4 protein abundance and also inhibited the insulin signaling cascade. Overexpression of Nox4 also significantly reversed the inhibition of insulin-stimulated IR tyrosine phosphorylation induced by coexpression of PTP1B by inhibiting PTP1B catalytic activity. These data suggest that Nox4 provides a novel link between the IR and the generation of cellular reactive oxygen species that enhance insulin signal transduction, at least in part via the oxidative inhibition of cellular protein-tyrosine phosphatases (PTPases), including PTP1B, a PTPase that has been previously implicated in the regulation of insulin action

    Preschool children’s biophilia and attitudes toward nature: The effect of personal experiences

    Get PDF
    Regular engagement outside may promote healthy physical and psychological development as well as a respect and appreciation for nature. This exploratory study compared biophilia and attitudes toward nature between young children living in an urban area to those in a rural area. Urban and rural areas may offer different opportunities for exposure and engagement with elements such as water, plants, and animals. A comparison between young children in these settings may determine if experience in these different environments affects their attitudes and biophilia. Thirty-six children (urban n = 27; rural n = 9) participated in one-on-one structured interviews about their attitudes toward and being in nature. Results revealed no significant difference in biophilia between children by geographical area. Common themes in children’s attitudes emerged: 1) young children define nature by identifying specific elements; 2) young children are aware that their actions have consequences for the condition of the natural environment; and 3) children understood that the expectations guiding behavior in the natural environment apply to everyone. Preschool children’s level of cognitive maturity and individual preferences may be better predictors of biophilia and attitude than location alone. Authors suggest implications for teachers and parents

    Panel Discussion: Regulation of Natural Resource Development

    Get PDF
    This panel discussion is part of the symposium: Canada and the United States: A Changing Relationship in a Changing World. A lively discussion of trade issues, laws and treatment of investments between the United States and Canada

    Preschool children’s biophilia and attitudes toward nature: The effect of personal experiences

    Get PDF
    Regular engagement outside may promote healthy physical and psychological development as well as a respect and appreciation for nature. This exploratory study compared biophilia and attitudes toward nature between young children living in an urban area to those in a rural area. Urban and rural areas may offer different opportunities for exposure and engagement with elements such as water, plants, and animals. A comparison between young children in these settings may determine if experience in these different environments affects their attitudes and biophilia. Thirty-six children (urban n = 27; rural n = 9) participated in one-on-one structured interviews about their attitudes toward and being in nature. Results revealed no significant difference in biophilia between children by geographical area. Common themes in children’s attitudes emerged: 1) young children define nature by identifying specific elements; 2) young children are aware that their actions have consequences for the condition of the natural environment; and 3) children understood that the expectations guiding behavior in the natural environment apply to everyone. Preschool children’s level of cognitive maturity and individual preferences may be better predictors of biophilia and attitude than location alone. Authors suggest implications for teachers and parents

    Estimasi Biomasa Dan Karbon Tersimpan Pada Pinus Merkusii Jungh. & De Vriese Di Hutan Pinus Gn. Bunder, Tn. Gn. Halimun Salak [Biomass Estimation and Carbon Stock on Pinus Merkusii Jungh. & De Vriese in Pine Forest at Bunder Mount, Gunung Halimun Salak National Park]

    Full text link
    A study on the biomass and carbon stock estimation of Pinus merkusii Jungh. & de Vriese plantation has been conducted on 17-years and 30-years old pine forest in Gunung Bunder, Halimun Salak National Park. The method used was the allometric with non destructive technique. The results showed that pine trees density of 30-years old pine was 542 trees ha-1 ; the basal area (BA) was 26.8 m2 ha-1; trees density of 17-years old pine was 1,398 tree ha-1 with BA was 36.2 m2 ha-1. The estimation of biomass, carbon sinks and CO2 sequestration of 30-years old pine were 203.7, 96.5 and 354.2 ton ha-1, respectively. Meanwhile, the estimation of biomass, carbon sinks and CO2 sequestration of 17-years old pine were 188.3, 86.8 and 318.5 ton ha-1, respectively. Value of the environmental services derived from the CO2 absorption for the development of a pine forest ranged from US.$ 1,847.09 to 2,054.22, at two ages of pine trees

    KUAT TEKAN BETON DENGAN BAHAN TAMBAH SERBUK KACA SEBAGAI SUBSTITUSI PARSIAL SEMEN

    Get PDF
    ABSTRAKTeknologi beton telah berkembang sejak ditemukannya beton prategang pada beberapa dekade lalu yang diikuti oleh berbagai penelitian untuk meningkatkan kinerja bahan bangunan. Penelitian tersebut dilakukan dengan memperhatikan pemilihan material pembentuk beton sampai pada substitusi material lainnya, dengan memperhatikan adanya limbah kaca baik yang berasal dari industri ataupun pembongkaran bangunan dan dari rumah tangga dalam jumlah besar, berkemungkinan dimanfaatkan sekaligus sebagai alternatif solusi permasalahan lingkungan yang dapat diakibatkan oleh limbah kaca. Serbuk kaca diharapkan berfungsi sebagai filler karena memiliki potensi sebagai material pozzolan. Perencanaan campuran beton menggunakan Metode ACI 211.1 – 91 yang dimodifikasi.Penelitian ini menggunakan kaca dengan variasi penggunaannya 0%, 6%, 8%, 10%, 12%, dan 15% dengan kode secara berurutan sebagai berikut kaca – 0%, kaca – 6%, kaca – 8%, kaca – 10%, kaca – 12%, kaca – 15%. Pengujian dilakukan terhadap berat volume dengan menggunakan benda uji silinder 10/20 cm untuk umur 1 hari dan kuat tekan beton untuk umur 7, 14, dan 28 hari.Berat volume untuk semua variasi penggunaan serbuk kaca termasuk beton normal. Beton dengan nilai kuat tekan tertinggi dicapai pada komposisi serbuk kaca 10% sedangkan nilai kuat tekan terendah di dapat pada komposisi kaca 15%.Kata kunci : serbuk kaca, berat volume, kuat tekan, limbah kac

    Zooplankton Community In Coastal Malalayang Waters Manado

    Get PDF
    The purpose of this study was to identify the zooplankton, to know the relative density of zooplankton, and to analyze their community structure, such as Diversity Index (H') and Dominance Index (C).Sampling was conducted on September 30th, 2016 at the depth of 50 cm-withdrawn slowly along 40 meter (2x20 meter back and forth) in each station. The water left in the cod end (reservoir bottle) put into a sample bottle, with alcohol 95%, and taken to the laboratory for identification.Based on the identification, there were 25 species of zooplankton (19 adults, one final larval stage brachyura, 4 larvae of mollusks and worms, and 1 fish larvae 1 unidentified), namely: Oncaea sp. [1], Oncaea sp. [2], Oncaea sp. [3], Diastylis sp., Monstrilla sp., Euchaetomera sp., Euchaeta sp., Ibacus sp., Oithona sp., Synchaeta sp., Farranula sp., Macrosetella sp., Eurydice sp., Calanus sp., Lucifer sp., Eucalanus sp., Scolecithricella sp., Lucicutia sp., Lepidasthenia sp., megalops brachyura, zoea brachyura, larvae of eulimella, larvae of echinospira, larvae of corethra and larvae of fish. Relative density was the highest in Oncaea sp. (34.21%) and Diversity Index (H') was classified as moderate. The diversity index showed that the zooplankton community was less diverse. Dominance Index (C) was also low indicating no species was dominant in the coastal waters of Malalayang.Keyword : Community, zooplankton, Malalayang DuaAbstrak Tujuan penelitian ini adalah untuk mengetahui jenis–jenis zooplankton, mengetahui kepadatan relatif zooplankton, dan menganalisa struktur komunitas zooplankton seperti Indeks Keanekaragaman (H’) dan Indeks Dominasi (C).Pengambilan sampel dilakukan pada 30 September 2016 dengan cara memasukkan plankton net sedalam 50 cm, kemudian ditarik sambil berjalan secara perlahan sepanjang 40 meter (2x20 meter bolak-balik) di tiap stasiun. Air yang tersaring dalam cod end (botol penampungan) dituangkan di dalam botol sampel dan ditambahkan/diawetkan dengan alkohol 95%. Selanjutnya, sampel tersebut dibawa ke Laboratorium untuk diidentifikasi.Berdasarkan hasil identifikasi diperoleh 25 jenis zooplankton (19 dewasa, 1 organisme muda [tahap akhir larva] zooplankton, 4 larva zooplankton dan 1 larva ikan yang tidak teridentifikasi) yaitu: Oncaea sp. [1], Oncaea sp.[2], Oncaea sp.[3], Diastylis sp., Monstrilla sp., Euchaetomera sp., Euchaeta sp., Ibacus sp., Oithona sp., Synchaeta sp., Farranula sp., Macrosetella sp., Eurydice sp., Calanus sp., Lucifer sp., Eucalanus sp., Scolecithricella sp., Lucicutia sp., Lepidasthenia sp., Megalopa Brachyura, Zoea Brachyura, Larva Eulimella, Larva Echinospira, Larva Corethra dan Larva Ikan. Kepadatan Relatif tertinggi terdapat pada Oncaea sp. sebesar 34,21% Nilai Indeks Keanekaragaman (H’) zooplankton di tiga Stasiun tergolong sedang. Nilai tersebut menunjukkan bahwa komunitas organisme dalam kondisi yang kurang beragam. Hasil Indeks Dominasi (C) termasuk kriteria dominasi rendah, menunjukkan bahwa tidak ada spesies yang mendominasi di perairan pantai Malalayang.Kata kunci : Komunitas, zooplankton, Malalayang Du

    Length-weight relationship and gonadal index of juvenile bluestripe snapper Lutjanus kasmira (ForsskĂĄl, 1775) in the waters around Tanamon Village South Minahasa

    Get PDF
    This study aims to determine the length-weight relationship, growth patterns, and gonadal index of juvenile bluestripe snapper Lutjanus kasmira. Samples were collected using a hand line with a hook numbered  3 and a monofilament fishing line numbered 80. Sampling activities were carried out on July 26th – August 4th, August 26th - September 4th, and October 10th, 2020. A total of 70 fish, 22 females and 48 males was caught. Female length distribution ranged from 104 to 150 mm with a weight range of 18.19-55.87 g, while male length ranged from 107 to 150 mm in length with a weight of 19.00-57.00 g. The length-weight relationship was indicated with W= 0.0177L2.9344 (R2=0,7816) for males and W = 0.012L3.0817 (R2=0,8976) for females with isometric growth pattern. The length-weight relationship for combined sexes was W= 0.0156L2.9816 (R2=0,8186) with an isometric growth pattern. The gonadal maturity for all samples was at immature and developing stages. The gonadal index in female snapper at immature was 0.16 and developing was 0.41, whereas the male gonadal maturity index at immature was 0.14 and developing was 0.38.Keywords: Lutjanus kasmira; length-weight; gonad maturity; gonadal indexAbstrakPenelitian ini bertujuan untuk mengetahui hubungan panjang berat, pola pertumbuhan dan indeks  gonad  ikan kakap Lutjanus kasmira. Sampel ikan ditangkap menggunakan pancing ulur mata pancing nomor  3 dan tali monofilament nomor 80. Aktivitas pengambilan sampel dilakukan masing-masing pada 26 Juli-4 Agustus, 26 Agustus-4 September 2020, dan 10 Oktober 2020. Sebanyak 70 individu sampel diperoleh, 22 betina dan 48 jantan. Sebaran ukuran panjang ikan betina  104-150 mm dan berat 18,19-55,87 g. Sebaran ukuran panjang ikan jantan 107-150 mm dan berat 19,00-57,00 g.     Hubungan panjang-berat diperoleh W= 0,0177L2,9344 (R2=0,7816) untuk jantan dan W = 0,012L3,0817 (R2=0,8976) untuk betina dengan pola pertumbuhan isometrik. Gabungan ikan kakap jantan dan betina diperoleh W= 0,0156L2,9816 (R2=0,8186)  dengan pola pertumbuhan isometrik. Tingkat kematangan gonad  (TKG) terhadap seluruh sampel baik jantan maupun betina berada pada TKG I (belum matang) dan TKG II (berkembang). Indeks  gonad pada ikan kakap betina pada TKG I sebesar 0,16 dan TKG II sebesar 0,41. Indeks kematangan gonad ikan kakap jantan pada TKG I sebesar 0,14 dan TKG II sebesar 0,38.Kata Kunci: Lutjanus kasmira, panjang-berat, kematangan gonad, indeks gonad
    • …
    corecore