585 research outputs found

    Dampak sosial budaya akibat menyempitnya lahan pertanian di desa Nangor Propinsi Kalimantan Tengah

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    Kalimantan Tengah merupakan sebuah propinsi yang mempunyai wilayah yang cukup luas dan belum banyak yang dibuka, baik untuk kepentingan pertanian, perikanan, petemakan, perkebunan, pemukiman, maupun perindustrian. Luas Propinsi Kalimantan Tengah bila dibandingkan dengan jumlah penduduknya yang relatif sedikit, sebenamya, lahan yang bisa dibuka untuk diusahakan cukup luas. Namun kualitas tanah di Kalimantan Tengah sangat rendah, yaitu meliputi tanah kelas IV, V, VI, dan VII. Tanah dengan klasifikasi demikian dianggap sebagai tanah yang tidak subur bagi usaha pertanian. Tanah yang subur dan cocok untuk pertanian bercocok tanam jumlahnya sangat terbatas dan sedikit. Sementara itu pemerintah melarang pembukaan hutang sebebas waktu dahulu karena hutanhutan itu pada umumnya sudah diserahkan pengusahaannya kepada para pemegang Hak Pengusahaan Hutan (HPH). Dengan demikian penebangan hutan untuk pembukaan ladang baru sudah hampir tidak mungkin lagi tanpa ijin dari pemerintah. Selain itu pertanian ladang berpindah-pindah sudah dianggap sebagai suatu "kejahatan" dan dianggap sebagai biang perusakan hutan

    Contributions to anelasticity in langasite and langatate

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    Maximization of the quality factors Q of langasite (LGS) and langatate (LGT) is necessary for optimal performance of acoustic resonators of these materials in frequency-control and high-temperature sensing applications. In this report, measurements and least-squares analysis of Q(-1) as a function of ultrasonic frequency and temperature of undoped LGS (100 K to 750 K) and LGT (300 K to 760 K) reveal a superposition of physical effects, including point-defect relaxations and intrinsic phonon-phonon loss. In LGS, these effects are superimposed on a large temperature-dependent background with weak frequency dependence that is interpreted as arising from a relaxation process with a distribution of activation energies. This distributed relaxation is suggested to be a result of anelastic kink migration. No evidence for a significant background of this form is found in the LGT specimen, consistent with the lower measured dislocation etch-pit density of this crystal. The analysis of the dependence of Q(-1) of LGT on frequency and temperature indicates that, at near-ambient temperatures, the damping in this specimen is close to the intrinsic limit determined by phonon-phonon interactions. Piezoelectric/carrier relaxation, which must occur at sufficiently elevated temperatures, is found not to be a significant contribution to Q(-1), relative to defect-related contributions, in either LGS or LGT in the measured range of temperatures

    Boron-oxygen defect in Czochralski-silicon co-doped with gallium and boron

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    We study the boron-oxygen defect in Si co-doped with gallium and boron with the hole density 10 times higher than the boron concentration. Instead of the linear dependence of the defect density on the hole density observed in boron and phosphorus compensated silicon, we find a proportionality to the boron concentration. This indicates the participation of substitutional, rather than interstitial,boron in the defect complex. The measured defectformationrate constant is proportional to the hole density squared, which gives credit to latent defect models against defectreactions limited by the diffusion and trapping of oxygen dimers by boron atoms

    Analysis of CDMA systems that are characterized by eigenvalue spectrum

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    An approach by which to analyze the performance of the code division multiple access (CDMA) scheme, which is a core technology used in modern wireless communication systems, is provided. The approach characterizes the objective system by the eigenvalue spectrum of a cross-correlation matrix composed of signature sequences used in CDMA communication, which enables us to handle a wider class of CDMA systems beyond the basic model reported by Tanaka. The utility of the novel scheme is shown by analyzing a system in which the generation of signature sequences is designed for enhancing the orthogonality.Comment: 7 pages, 2 figure

    Nanoparticle sensor for label free detection of swine DNA in mixed biological samples

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    We used 40 ± 5 nm gold nanoparticles (GNPs) as colorimetric sensor to visually detect swine-specific conserved sequence and nucleotide mismatch in PCR-amplified and non-amplified mitochondrial DNA mixtures to authenticate species. Colloidal GNPs changed color from pinkish-red to gray-purple in 2 mM PBS. Visually observed results were clearly reflected by the dramatic reduction of surface plasmon resonance peak at 530 nm and the appearance of new features in the 620–800 nm regions in their absorption spectra. The particles were stabilized against salt-induced aggregation upon the adsorption of single-stranded DNA. The PCR products, without any additional processing, were hybridized with a 17-base probe prior to exposure to GNPs. At a critical annealing temperature (55 °C) that differentiated matched and mismatched base pairing, the probe was hybridized to pig PCR product and dehybridized from the deer product. The dehybridized probe stuck to GNPs to prevent them from salt-induced aggregation and retained their characteristic red color. Hybridization of a 27-nucleotide probe to swine mitochondrial DNA identified them in pork–venison, pork–shad and venison–shad binary admixtures, eliminating the need of PCR amplification. Thus the assay was applied to authenticate species both in PCR-amplified and non-amplified heterogeneous biological samples. The results were determined visually and validated by absorption spectroscopy. The entire assay (hybridization plus visual detection) was performed in less than 10 min. The LOD (for genomic DNA) of the assay was 6 µg ml − 1 swine DNA in mixed meat samples. We believe the assay can be applied for species assignment in food analysis, mismatch detection in genetic screening and homology studies between closely related species

    Enhanced sensing of dengue virus DNA detection using O2 plasma treated-silicon nanowire based electrical biosensor

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    Dengue Virus (DENV) has become one of the most serious arthropod-borne viral diseases, causing death globally. The existing methods for DENV detection suffer from the late stage treatment due to antibodies-based detection which is feasible only after five days following the onset of the illness. Here, we demonstrated the highly effective molecular electronic based detection utilizing silicon nanowire (SiNW) integrated with standard complementary metal-oxide-semiconductor (CMOS) process as a sensing device for detecting deoxyribonucleic acid (DNA) related to DENV in an early stage diagnosis. To transform the fabricated devices as a functional sensing element, three-step procedure consist of SiNW surface modification, DNA immobilization and DNA hybridization were employed. The detection principle works by detecting the changes in current of SiNW which bridge the source and drain terminal to sense the immobilization of probe DNA and their hybridization with target DNA. The oxygen (O2) plasma was proposed as an effective strategy for increasing the binding amounts of target DNA by modified the SiNW surface. It was found that the detection limit of the optimized O2 plasma treated-SiNW device could be reduced to 1.985 × 10−14 M with a linear detection range of the sequence-specific DNA from 1.0 × 10−9 M to 1.0 × 10−13 M. In addition, the developed biosensor device was able to discriminate between complementary, single mismatch and non-complementary DNA sequences. This highly sensitive assay was then applied to the detection of reverse transcription-polymerase chain reaction (RT-PCR) product of DENV-DNA, making it as a potential method for disease diagnosis through electrical biosensor

    Chirality scenario of the spin-glass ordering

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    Detailed account is given of the chirality scenario of experimental spin-glass transitions. In this scenario, the spin glass order of weakly anisotropic Heisenberg-like spin-glass magnets including canonical spin glasses are essentially chirality driven. Recent numerical and experimental results are discussed in conjunction with this scenario.Comment: Submitted to J. Phys. Soc. Japan "Special Issue on Frustration

    Genome-wide association scan meta-analysis identifies three Loci influencing adiposity and fat distribution.

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    To identify genetic loci influencing central obesity and fat distribution, we performed a meta-analysis of 16 genome-wide association studies (GWAS, N = 38,580) informative for adult waist circumference (WC) and waist-hip ratio (WHR). We selected 26 SNPs for follow-up, for which the evidence of association with measures of central adiposity (WC and/or WHR) was strong and disproportionate to that for overall adiposity or height. Follow-up studies in a maximum of 70,689 individuals identified two loci strongly associated with measures of central adiposity; these map near TFAP2B (WC, P = 1.9x10(-11)) and MSRA (WC, P = 8.9x10(-9)). A third locus, near LYPLAL1, was associated with WHR in women only (P = 2.6x10(-8)). The variants near TFAP2B appear to influence central adiposity through an effect on overall obesity/fat-mass, whereas LYPLAL1 displays a strong female-only association with fat distribution. By focusing on anthropometric measures of central obesity and fat distribution, we have identified three loci implicated in the regulation of human adiposity
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