820 research outputs found

    Phosphorus Dynamics and Bioavailability in Andosols : Estimation of Potential Bioavailable P Transport in Agricultural Runoff of Andosols

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    In this study, we estimated the potential bioavailable P transport in agricultural runoff of Andosols from the relations between P sorption saturation and anion exchange resin and Mehlich-3 extractable P, with special references to the difference in active Al composition. the P sorption saturation of 10%, that is optimum P level needed for good crop yields, is critical point of inorganic P for the potential bioavailable P loss in surface runoff from agricultural Andosols with different active Al composition. However, silandic A and B soils showed lower values of Mehlich-3 P than aluandic soils when they had the same P sorption saturation. Mehlich-3 P underestimated the bioavailability of soil P in the silandic soils compared to the aluandic soils. We recommend the use of different critical values of Mehlich-3 P for assessing the upper critical limits for P in aluandic and silandic Andosols

    Multiple linear regression with constrained coefficients: Application of the lagrange multiplier

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    In this paper, we present two unfamiliar novel estimation techniques (UNET) for the constrained regression coefficients in the frame-work of a standard multiple linear regression model. Estimation of a linear regression problem with constraints on the regression coefficients are firstly derived by minimising a formulated goal function that minimises the total sum of the squared errors, plus the sum of the linear constraints multiplied by a Lagrangian. We also show that the solution to the system of equations can be obtained without differentiating the goal function, rather expressed in terms of the known matrices. This is achieved by employing properties of a blocked linear system. The UNET is justified by a numerical simulated system of linear equations in 3-dimensions. The UNET yields estimates that are comparable to those generated by the Schur complement principle

    Tuna and tuna-like fish resources in the South China Sea and adjacent waters

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    The distribution of tunas and billfishes in the South China Sea and the Southeast Asian waters was shown on the commercial longline data. The seasonal changes in the hook-rate and the size composition of the yellowfin and bigeye tuna in the South China Sea were given and the previous suppositions on their stock structures in adjacent areas, the Indonesian waters and the Indian Ocean, were reviewed. The estimated Japanese longline catches from the South China Sea attained their peak of about 6,800 tons in 1967 and since then they have fluctuated between 2,000 and 5,000 tons with somewhat downward trend. The yellowfin and bigeye tuna accounted for ninety percent of the Japanese catch more. The remainder was occupied by the billfish, mostly the blue marlin and black marlin. The total longline catch by the Japanese and Taiwanese fisheries from the South China Sea area were roughly estimated to be between 5,000 and 8,000 tons in a recent few years. Among the small-sized tuna and tuna-like fishes, the skipjack, little tuna, longtail tuna, frigate mackerel and bonito seemed to be promising for their future exploitation. The biological information on some of them was briefly reviewed. Recent activities in research on tuna fisheries in the Indo-Pacific areas (IPFC area) have been fully reviewed by Suda (1971). For the South China Sea area, however, little has been reported on the biology of large-sized tuna except a few studies (Nakamura, 1953), although this area has long supported the tuna longline fleets from Taiwan and Japan. The purposes of this paper are: (1) to show the distribution of tunas and billfishes caught by the Japanese commercial longline fishery in the South China Sea and its adjacent waters on the past data, (2) to show the recent trend in the longline catches from these areas and (3) to make a short review on the occurrence of small-sized tuna and tuna-like fishes in Southeast Asian waters

    A Case of Pleuroperitoneal Communication in Continuous Ambulatory Peritoneal Dialysis

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    We present a patient who developed a massive right-Sided hydrothorax two months after starting CAPD treatment, a 41-year-old female with IgA nephropathy who was followed up at our outpatient clinic. Due to deteriorating renal function, a peritoneal catheter was inserted on March 29, 1997.CAPD was implemented on the same day. At the time when CAPD was initiated, the patient was experienclng repeated episodes of nausea and vomiting, probably due to uremia. On May 27, she developed dyspnea. A chest X-ray Showed massive right-Sided hydrothorax. After extracorporeal ultrafiltration was performed, the patient's respiratory distress was rapidly relieved. Two days later, CAPD was esumed, but this resulted in almost immediate recurrence of massive right-sided hydrothorax. The property of the drained fluid from the right pleural cavity and scintigraphy uslng Technetium-99m macroaggregated albumin confirmed pleuroperitoneal communication. Increased intra-abdominal pressure due to frequent vomiting may be responsible for hydrothorax due to pleuroperitoneal communication

    Polarity reversals of remanent magnetization in a sedimentary core from Northwind Ridge, western Arctic Ocean

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    We studied the remanent magnetization of a sedimentary core PC2 (6.48m length) drilled during the MR99-K05 cruise of JAMSTEC in the western Arctic Ocean. Discrete specimens and u-channel samples were used in the study. In the discrete specimens, the change of remanent magnetization with depth show many clear polarity reversals in both inclination and declination. Furthermore, most reversals in discrete specimens correlated well with those in the u-channel samples. Core PC2 is characterized by distinct alternations of dark gray and brownish layers. Through comparison of lithostratigraphic cycles with glacial-interglacial cycles (referring to R.L. Phillips and A. Grantz, Geol. Soc. Am. Bull., 109, 1101, 1997), sedimentary cycles of core PC2 are correlated to marine isotope stages up to MIS-8. This indicates that polarity reversals of remanent magnetization in core PC2 are geomagnetic excursions in the Brunhes epoch. Comparison with the previously known geomagnetic excursions shows that the polarity reversals are clear and have long duration in core PC2. This feature may be related to characteristic geomagnetism around the western Arctic Ocean

    Paleomagnetic Results from Luzon and the Central Philippines

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    Samples were collected from 86 paleomagnetic sites from the islands of Luzon, Marinduque, Mindoro, Panay, Negros, Cebu, and Mindanao in the Philippine Arc. The sampling sites range in age from Pleistocene to Jurassic. Characteristic directions of magnetization of the samples were determined by the use of vector plots. Curie temperature determinations, thin section studies, and hysteresis studies showed that remanence of these samples is carried by fine-grained (pseudo-single domain) magnetite. Positive fold tests from Miocene data from Panay, Jurassic data from Mindoro, and Cretaceous data from Cebu suggest that the magnetization of these regions was acquired prior to folding. Rotations reported below are measured with respect to the axial goecentric dipole field. The Plio-Pleistocene data set shows no resolvable rotation for the 22 sites. This data set suggests that the various terranes that make up the Philippine Arc have behaved as a single unit during the past 5 m.y. or that deformation has been below the limits of resolution. The inclination data from the Plio-Pleistocene sites have anomalously shallow inclination and are consistent with other Plio-Pleistocene data from Vietnam, Taiwan, and the Marianas. These data support earlier suggestions for a late Neogene offset dipole effect. The late Miocene sites fall into two separate groups. Ten sites from western Luzon show evidence for around 20° of clockwise rotation. In contrast to this, late Miocene samples from the Bicol region, Negros, Marinduque, and Mindanao are not rotated. The cause of the postlate Miocene clockwise rotation of Luzon is unknown, but a Pliocene collision of the North Luzon Arc with Taiwan is suggested. Early Neogene results also separate into two different populations. The population from Marinduque shows evidence for a large counterclockwise rotation. The second early Neogene population comes from Panay, Cebu, and Mindanao and clearly shows evidence for a clockwise rotation. The validity of this rotation is further supported by a fold test and a reversal test. These early Neogene data sets are consistent with a middle to late Miocene collision of the Palawan Continental Terrane and the Central Philippine Arc. Data from six dikes of possible Oligocene age from the Zambales Ophiolite are highly discordant from the present field, being rotated approximately 60° clockwise. The directions from these dikes are similar to a direction reported earlier from late Oligocene sediments also from the Zambales region. These two data sets support the interpretation that the Eocene direction from Zambales is recording a large clockwise rotation of the region. Data from the Mesozoic sites are from two regions. Data from the Cretaceous Pandan formation of Cebu are discordant with data from the Upper Jurassic from Mindoro. The presence of a fold test from each region and a reversal test from Mindoro supports the interpretation that each of these data sets is reliable. The VGP of Mindoro is displaced southward from the Late Jurassic VGP of South China, suggesting a post-Jurassic southward migration of Mindoro
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