89 research outputs found

    Pola Anomali Magnet dan Nilai Susceptibilitas dari Batuan Dasar pada Pemetaan Geologi dan Geofisika di Perairan Teluk Bone Sulawesi Selatan

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    Pola anomali magnet dari penerapan metode reduksi kekutub dan equator menunjukkan nilai anomali lokal yang cukup signifikan. Nilai anomali magnet di perairan Teluk Bone diduga berkaitan dengan tatanan litologi batuan dasar. Nilai anomali negatif dengan notasi warna biru yang menempati bagian utara dan tenggara daerah penelitian, diduga merupakan batuan sedimen yang mendominasi daerah tersebut. Sifat kemagnitan batuan di bagian barat daerah penelitian, diduga disebabkan oleh busur magmatik dari tepian timur lengan Sulawesi Selatan. Nilai susceptibilitasnya (k) tertinggi mulai dari 0.1588 hingga 0.1596, sedangkan terendah mulai dari 0.1564 sampai 0.1572. Diperkirakan nilai susceptibilitas tertinggi, termasuk dalam kelompok batuan metamorf, sedangkan terendah termasuk dalam kelompok batuan sedimen. Kata kunci : anomali lokal, susceptibilitas The pattern of magnetic anomalies of the application the method of reduction to the pole and equator shows the value of the local anomalies are quite significant. The value of magnetic anomalies in the waters of the Gulf of Bone allegedly related to order litologi bedrock. The value of negative anomalies with blue color notation that occupy the north and southeast region research, allegedly is a sedimentary rock that dominates the area. The nature of magnetic rocks in the western part of the area of research, allegedly caused by the arc of the east arm magmatic South Sulawesi. The value of the highest susceptibilitasnya (k) ranging from 0.1588 until 0.1596, whereas the lowest starting from 0.1564 until 0.1572. Estimated value of the highest susceptibility, included in the group of metamorphic rock, while the lowest are included in the group of sedimentary rocks. Keywords: local anomaly, susceptibilit

    Penentuan Lokasi Turbin Pembangkit Listrik Tenaga Arus Laut Skala Kecil Di Perairan Selat Lirung, Talaud, Sulawesi Utara

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    Selat Lirung adalah selat yang terletak antara Pulau Salibabu dan Pulau Karakelong, Kepulauan Talaud. Penelitian potensi energi arus laut telah dilakukan di lokasi ini, untuk mengkaji kemungkinan dikembangkannya Pembangkit Listrik Tenaga Arus Laut (PLTAL) skala kecil (2 kW) dengan model turbin sumbu vertikal. Salah satu tahapan dalam implementasi PLTAL skala kecil adalah penentuan lokasi penempatan turbin. Beberapa kriteria teknis yang dipersyaratkan harus dipenuhi pada tahapan ini. Untuk maksud tersebut dilakukan kajian awal dengan melakukan analisis data kedalaman laut, Sea Bottom Profiling (SBP), arus bergerak, arus insitu, pasang surut, dan meteorologi. Data tersebut direpresentasikan dalam data kecepatan arus laut, morfologi dasar laut, kedalaman laut, durasi waktu kecepatan arus kuat, jarak terhadap garis pantai, dan pengaruh gelombang laut. Berdasarkan hasil analisis data tersebut diperoleh 2 (dua) lokasi yang paling representatif. Lokasi pertama di alur antara P. Sara Besar dengan Sara Kecil pada kedalaman laut sekitar 25 m dengan kecepatan arus maksimum sebesar 1.0 m/det-1.75 m/det. Sedangkan lokasi kedua di alur antara P. Sara Besar dengan P. Salibabu pada kedalaman laut antara 25 m-35 m dengan kecepatan arus maksimum sebesar 1.0 m/det-1.3 m/det. Kata kunci Tenaga arus laut, turbin, kecepatan arus, morfologi dasar laut, kedalaman laut The Lirung Strait is a strait located between the Salibabu Island and Karakelong Island, Talaud. Energy potential of marine current research has been done in this location, to examine the possibility of the development of Marine Current Power Plant (MCPP) small scale (2 kW). One of the stages in the implementation of MCPP small scale is determining the location of the turbines placement. Some technical criteria required to be met at this stage. For the purpose of initial studies to perform data analysis depth of the sea, Sea Bottom Profiling (SBP), the current is moving, insitu currents, tides, and meteorology. That data are represented within the sea current speed, the morphology of the seabed, ocean depth, duration of strong current speed, distance to the coastline,and the influence of waves. Based on the results of the analysis of the data obtained two (2) most representative locations. The first location is in the groove between the Sara Besar Island with Sara Kecil Island at the depths between 25 m with the maximum current speed of 1.0 m/s-1.75 m/s. The second location is in the groove between the Sara Besar Island with Salibabu Island at the depths between 25 m - 35 m with the maximum current speed of 1.0 m/s-1.3 m/s

    Pola Anomali Magnet Lokal Dari Aplikasi Trend Surface Analysis (Tsa) Pada Pemetaan Geologi Kelautan Bersistem Di Perairan Selat Malaka Sumatera Utara

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    Analisis intensitas magnet dari penerapan metode TSA orde ke 2 menunjukkan nilai anomali lokal yang cukup signifikan dari pemisahan nilai anomali magnet total di perairan Selat Malaka. Kontur anomali lokal yang dihasilkan diduga berkaitan dengan pola struktur geologi busur belakang Sumatera Utara. Kata kunci : anomali lokal, metode TSA Analysis of magnetic intensity using 2nd orde of the TSA method shows a significant value of local anomaly from the separation of total magnetic anomaly value in the Malaka Strait waters. Contour of the local anomaly resulted is assumed to be correlated with the geological structure pattern of back arc of North Sumatera. Keyword : local anomaly, TSA metho

    Potensi Arus Laut dan Konversi Daya Listrik sebagai Energi Baru Terbarukan di Perairan Palalawan dan Indragiri Hilir, Provinsi Riau

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    Kecepatan arus pada saat kondisi air surut di bagian utara daerah penelitian berkisar antara 1 – 1,5 m/s dan di selatan berkisar antara 0,1 – 0,5 m/s dengan arah menuju tenggara - selatan. Pada saat kondisi air pasang pada kedua daerah tersebut (bagian utara dan selatan) kecepatan arus berkisar antara 0,5 – 1,2 m/s dengan arah menuju barat daya - utara. Secara umum kecepatan arus dari utara ke selatan semakin berkurang kecepatannya, hal ini bisa dilihat dari perbedaan kecepatan arus di bagian utara dan selatan daerah penelitian pada kondisi air laut surut. Kondisi tersebut disebabkan oleh perbedaan morfologi bawah laut pada ke dua daerah tersebut. Di bagian utara, lebar lembah relatif lebih sempit (daerah selat) dengan morfologi membentuk alur bawah laut. Di bagian selatan merupakan daerah perairan terbuka, menyebabkan aliran air laut dan arus terdistribusi pada daerah yang lebih luas dan kecepatan arusnya makin berkurang. Potensi daya listrik untuk Turbin Kobold saat surut mencapai 60 – 65 kW, dan 20 kW saat pasang selama 13 jam, sedangkan saat neap tide maksimum mencapai 8 kW saat surut dan 4 kW saat pasang dengan waktu efektif selama 11 jam. Potensi daya listrik untuk Turbin Marine Current saat surut mencapai 3 – 3,2 kW dan 1 kW saat pasang dengan masa kerja selama 13 jam dalam sehari semalam, sedangkan saat neap tide maksimum mencapai 0,4 kW saat surut dan 0.2 kW saat pasang dengan waktu efektif selama 10 jam. Jenis turbin ini cukup optimal dan dapat bekerja dengan baik untuk menghasilkan listrik dengan potensi arus yang ada di perairan Pelalawan – Indragiri Hilir. Kata kunci: kecepatan arus, energi, potensi daya listrik, turbin Current speed during the low waters level in the northern part of survey area range between 1 to 1.5 m/s with southeast and south direction. During the high waters level (HWL) in the both areas range from 0.1 – 0.5 m/s with southwest and north direction. Generally, the current speed from the north to the south in the survey area is decrease, it can be seen from difference value of current speed at the northern and the southern of the survey area during the low waters level (LWS) condition. These condition caused by the difference of under sea morphology at bothside of areas. At the northern part of survey area, the wide of valley morphology is smaller (straits region) forming the submarine channel. At the southern part in an opening waters region, causing the sea current distributed in regions and the speed more decreasing. Electrical potency for Kobold Turbine during ebb tide reach 60 - 65 kW, and 20 kW during the flood as long as 13 hours, while during maximum neap tide reach 8 kW during the ebb and 4 kW during the flood with effective time as long as 11 hours. Electrical Potential for Marine Current Turbine during ebb reach 3 – 3.2 kW, and 1 kW during the flood as long as 13 hours, while during maximum neap tide reach 0.4 kW during the ebb and 0.2 kW during the flood with effective time as long as 10 hours. This kind of the turbine is optimum enough and can work well to produce the electricity with existing current potential in waters of Pelalawan – Indragiri Hilir. Keywords: current speed, energy, electrical potency, turbin

    Scaling in the Bombay Stock Exchange Index

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    In this paper we study BSE Index financial time series for fractal and multifractal behaviour. We show that Bombay stock Exchange (BSE)Index time series is mono-fractal and can be represented by a fractional Brownian motion.Comment: 11 pages,3 figure

    Dynamic correlations in an ordered c(2×\times2) lattice gas

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    We obtain the dynamic correlation function of two-dimensional lattice gas with nearest-neighbor repulsion in ordered c(2×\times2) phase (antiferromagnetic ordering) under the condition of low concentration of structural defects. It is shown that displacements of defects of the ordered state are responsible for the particle number fluctuations in the probe area. The corresponding set of kinetic equations is derived and solved in linear approximation on the defect concentration. Three types of strongly correlated complex jumps are considered and their contribution to fluctuations is analysed. These are jumps of excess particles, vacancies and flip-flop jumps. The kinetic approach is more general than the one based on diffusion-like equations used in our previous papers. Thus, it becomes possible to adequately describe correlations of fluctuations at small times, where our previous theory fails to give correct results. Our new analytical results for fluctuations of particle number in the probe area agree well with those obtained by Monte Carlo simulations.Comment: 10 pages, 7 figure

    The genetic aetiology of cannabis use initiation: a meta-analysis of genome-wide association studies and a SNP-based heritability estimation

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    While initiation of cannabis use is around 40% heritable, not much is known about the underlying genetic aetiology. Here, we meta-analysed two genome-wide association studies of initiation of cannabis use with >10000 individuals. None of the genetic variants reached genome-wide significance. We also performed a gene-based association test, which also revealed no significant effects of individual genes. Finally, we estimated that only approximately 6% of the variation in cannabis initiation is due to common genetic variants. Future genetic studies using larger sample sizes and different methodologies (including sequencing) might provide more insight in the complex genetic aetiology of cannabis use

    Combined Genome Scans for Body Stature in 6,602 European Twins: Evidence for Common Caucasian Loci

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    Twin cohorts provide a unique advantage for investigations of the role of genetics and environment in the etiology of variation in common complex traits by reducing the variance due to environment, age, and cohort differences. The GenomEUtwin (http://www.genomeutwin.org) consortium consists of eight twin cohorts (Australian, Danish, Dutch, Finnish, Italian, Norwegian, Swedish, and United Kingdom) with the total resource of hundreds of thousands of twin pairs. We performed quantitative trait locus (QTL) analysis of one of the most heritable human complex traits, adult stature (body height) using genome-wide scans performed for 3,817 families (8,450 individuals) derived from twin cohorts from Australia, Denmark, Finland, Netherlands, Sweden, and United Kingdom with an approximate ten-centimorgan microsatellite marker map. The marker maps for different studies differed and they were combined and related to the sequence positions using software developed by us, which is publicly available (https://apps.bioinfo.helsinki.fi/software/cartographer.aspx). Variance component linkage analysis was performed with age, sex, and country of origin as covariates. The covariate adjusted heritability was 81% for stature in the pooled dataset. We found evidence for a major QTL for human stature on 8q21.3 (multipoint logarithm of the odds 3.28), and suggestive evidence for loci on Chromosomes X, 7, and 20. Some evidence of sex heterogeneity was found, however, no obvious female-specific QTLs emerged. Several cohorts contributed to the identified loci, suggesting an evolutionarily old genetic variant having effects on stature in European-based populations. To facilitate the genetic studies of stature we have also set up a website that lists all stature genome scans published and their most significant loci (http://www.genomeutwin.org/stature_gene_map.htm)

    Comparative genetic architectures of schizophrenia in East Asian and European populations

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    Schizophrenia is a debilitating psychiatric disorder with approximately 1% lifetime risk globally. Large-scale schizophrenia genetic studies have reported primarily on European ancestry samples, potentially missing important biological insights. Here, we report the largest study to date of East Asian participants (22,778 schizophrenia cases and 35,362 controls), identifying 21 genome-wide-significant associations in 19 genetic loci. Common genetic variants that confer risk for schizophrenia have highly similar effects between East Asian and European ancestries (genetic correlation = 0.98 ± 0.03), indicating that the genetic basis of schizophrenia and its biology are broadly shared across populations. A fixed-effect meta-analysis including individuals from East Asian and European ancestries identified 208 significant associations in 176 genetic loci (53 novel). Trans-ancestry fine-mapping reduced the sets of candidate causal variants in 44 loci. Polygenic risk scores had reduced performance when transferred across ancestries, highlighting the importance of including sufficient samples of major ancestral groups to ensure their generalizability across populations
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