11 research outputs found

    Urban coral reefs: Degradation and resilience of hard coral assemblages in coastal cities of East and Southeast Asia

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    © 2018 The Author(s) Given predicted increases in urbanization in tropical and subtropical regions, understanding the processes shaping urban coral reefs may be essential for anticipating future conservation challenges. We used a case study approach to identify unifying patterns of urban coral reefs and clarify the effects of urbanization on hard coral assemblages. Data were compiled from 11 cities throughout East and Southeast Asia, with particular focus on Singapore, Jakarta, Hong Kong, and Naha (Okinawa). Our review highlights several key characteristics of urban coral reefs, including “reef compression” (a decline in bathymetric range with increasing turbidity and decreasing water clarity over time and relative to shore), dominance by domed coral growth forms and low reef complexity, variable city-specific inshore-offshore gradients, early declines in coral cover with recent fluctuating periods of acute impacts and rapid recovery, and colonization of urban infrastructure by hard corals. We present hypotheses for urban reef community dynamics and discuss potential of ecological engineering for corals in urban areas

    Ammonium paratungstate as a raw material for the manufacturing of lamp filament tungsten wire

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    Applied Science

    X-ray powder diffraction data and unit cells of ammonium paratungstate tetrahydrate

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    X-Ray powder diffraction data and unit cell parameters of industrially produced, as well as bench scale prepared, ammonium paratungstate tetrahydrate are reported and compared with current Powder Data file (PDF) (1989) patterns. A least-squares refinement resulted in two slightly different unit cells. Both ceils are monoclinic with S.G. = P21/n(14), Z = 2. The density, 4.639(2)kg/m3, calculated from one of these unit cells corresponds reasonably well with a measured value of 4.61 (2). it has, however, not been possible to determine at present why ammonium paratungstate tetrahydrate has two unit cells. No relation between the crystalline form and the method of preparation nor the exact water content could be established

    Homocysteine metabolism and B-vitamins in schizophrenic patients: low plasma folate as a possible independent risk factor for schizophrenia.

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    Item does not contain fulltextTwo apparently unrelated disorders, neural tube defects (NTD) and schizophrenia showed increased risks in birth cohorts exposed to famine during early gestation. NTD is associated with impaired folate metabolism. We investigated whether schizophrenia is also linked with a dysfunctional folate metabolism. In addition to the prevalence of the 677C-->T mutation in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene, we compared plasma and red blood cell (RBC) folate, vitamin B6, vitamin B12, and homocysteine (Hcy) concentrations of 35 schizophrenic patients with those of 104 unrelated controls. Schizophrenic patients had significantly lower plasma folate concentrations after adjustment for Hcy levels, and elevated RBC folate levels compared to controls. Vitamin B6, vitamin B12, and Hcy levels did not differ from control values. Plasma folate levels below the 10th percentile of controls were associated with an approximate 4-7-fold (before and after adjustment of folate levels for Hcy, respectively) risk of having schizophrenia. In addition, a significant dose-response relation between plasma folate concentrations and risk for schizophrenia suggested a protective effect by high plasma folate concentrations. Elevated Hcy levels and, in line with this finding, homozygosity for the 677C-->T mutation in the MTHFR gene were not associated with an increased risk for schizophrenia. Evidence is presented suggesting that folate metabolism is disturbed in schizophrenic patients, independently of Hcy

    The Investigation of the Oxidation Kinetics of Phosphotungsten Suboxide

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    Dark blue colored phosphotungsten suboxide, which has the characteristics of phosphate tungsten oxide bronze, is formed during the thermal decomposition of ammonium phosphotungstate hydrate (APTH) in inert gas atmosphere. The aim of this study is to investigate the oxidation kinetics of phosphotungsten suboxide at isothermal conditions. Pellets prepared from phosphotungsten suboxide powder that were preheated at 1173 K temperature in inert gas atmosphere were used in the oxidation experiments. The sensitive measurement of weight increases was determined by the microelectronic microbalance. The oxidation reaction was carried out in the temperature range of 690 and 778 K and oxygen partial pressure range of 0.04 and 0.21 bar. The effects of gas flow rate, temperature, and oxygen partial pressure on the reaction rate were determined. The rate equation was derived by applying the "Nucleation and Growth Kinetics" model. The reaction rate was found to be of 0.94 order with respect to oxygen partial pressure, and the activation energy was 159 kJ mol(-1)
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