印度洋-太平洋海洋生态系统的占有:活礁鱼食品贸易的实例研究

我们对珊瑚礁渔业,特别是活礁鱼食品贸易(FT)的生态足迹的分析表明,许多国家目前的消费量超过了估计的可持续的人均全球、地区及地方珊瑚礁生产水平.香港通过其FT需求占有了东南亚年礁鱼生产量135 260～286 560t的25%,超过地区生物生产力8.3倍;礁鱼渔业需求超过印度洋-太平洋和东南亚地区可持续产量2.5～6倍.相比之下,大多数太平洋岛屿靠本身的礁渔业手段维持生计,当地的需求小于大洋洲整个能力的20%.FT每年需要多达40%东南亚的估计礁鱼产量以及几乎所有其估计的(鱼旨)科鱼产量.我们的研究分析结果强调了FT的不可持续性以及对印度洋-太平洋珊瑚礁渔业加以区域管理和保护的迫切必要性.     

Aus den frühen Tagen der Makromolekularen Chemie

Most branches of science pass through a “pioneering period” where different concepts and approaches create, for a while, a turbulent atmosphere until, on the basis of new experimental evidence, clear and durable principles emerge, which lead to a broad and continuous growth of basic understanding and practical application. The author of this article recalls how, temporarily, conflicting ideas created confusion in the chemistry and technology of giant molecules before these disciplines developed into what they are now: indispensable contributors to the comfort, safety and expansion of our society from medicine to astronautics.     

Modeling Land-Use Change in a Decision-Support System for Coastal-Zone Management

RaMCo is a prototype version of a decision-support system for coastal-zone management. The model is based on the findings of a multidisiciplinary research program, conducted in Southwest Sulawesi, Indonesia. Different management strategies can be compared on the basis of the short- and long-term consequences. Land-use change has been included in RaMCo in view of the impacts of land-based human activities on the marine environment. The key aspect of the model is a combination of the temporal dynamics of land-use change on the regional (macro-level) scale and spatial dynamics on the local (micro-level) scale. Constrained cellular automata are used to integrate both scale levels. The state changes of the cells depend on the consistency with the macro-scale model, local geographical conditions, and interaction with neighboring cells. In this paper, we discuss the underlying theoretical assumptions of the macro-scale and micro-scale models, some characteristic results for land-use change in the study area, and the validation problem.     

Benzene, toluene, ethyl benzene and xylenes in ambient air and Pinus sylvestris L. needles: a comparative study between Belgium, Hungary and Latvia

Concentrations of benzene, toluene, ethyl benzene and xylenes (BTEX) in ambient air and in 1 yr old Pinus sylvestris pine needles were monitored along a busy road, petrol station and rural area of Belgium, Hungary and Latvia in a 1 yr period. To test P. sylvestris as a possible biomonitor for the BTEX concentrations, samples were taken in the four seasons. As the distribution of data was not normal, the level of pollution on different sites and seasons was compared and evaluated by non-parametric tests. The measured air concentrations did not differ significantly from one season to another throughout the year. There were, however, differences between sampling places. The C₂-alkylbenzene and toluene concentrations in the needles were similar in the autumn/winter and spring/summer periods but a significant decrease in their concentration was observed in every place between winter and spring. This effect was less obvious for toluene.     

Excretion balance,metabolic fate and tissue residues following treatment of rats with amitraz and N‘‐ (2,4‐dimethylphenyl)‐N‐methylformamidine

Abstract

Amitraz and its metabolite N‘‐ (2,4‐dimethylphenyl)‐N‐methyl‐formamidine (BTS‐27271) were administered orally to white rats. Both compounds were rapidly metabolized and eliminated primarily via the urine. The cumulative percentage of the dose eliminated in the urine was 77.6 for amitraz and 88.7 for BTS‐27271 by 96 hr posttreatment. Amitraz degradation products present in urine included BTS‐27271, 2,4‐dimethylformanilide, 2,4‐dimethylaniline, 4‐formamido‐3‐methylbenzoic acid, 4‐amino‐3‐methylbenzoic acid, and several unknowns. BTS‐27271 degradation products in rat urine were similar to those found with amitraz. Tissue residues generally were low (<25 ppb) with the exception of those in liver.     

Current concepts of Down syndrome screening tests in assisted reproduction twin pregnancies: another double trouble

Assisted reproductive technologies (ART) have increased both the number of pregnancies in women beyond the age of 35 and the incidence of multiple pregnancies. Various methods of screening for Down syndrome (DS) were introduced in clinical practice during the last two decades, and specific problems were encountered when they were applied for twin pregnancies. The current review aims to explore the problematic issue of prenatal DS screening in ART twins. Overall, more women with twin pregnancies (mainly those who conceived via assisted reproduction) are found to be false positive for DS. This is because mid-trimester maternal serum screening is associated with a higher false-positive rate secondary to changes in the feto-placental endocrinologic metabolism, reflected mainly in high human chorionic gonadotrophin (hCG) levels in the ART pregnancies. First-trimester nuchal translucency (NT) measurement in twin pregnancies is not affected by the problems encountered in serum screening. This sonographic screening approach enables a fetus-specific identification of those fetuses at high risk of DS and is associated with a lower false-positive rate than mid-trimester serum screening. DS screening in ART twins presents several challenges in determining the most appropriate screening test modality. Whether there is any significant benefit of adding first-trimester biochemistry or nasal bone scanning in screening ART-conceived twins awaits further investigation. Copyright © 2005 John Wiley & Sons, Ltd.     

Effects of irrigation on the environment of selected areas of the Western United States and implications to world population growth and food production

Studies of irrigation drainage in the Western United States have documented some of the effects of irrigating land without first understanding and then considering implications from the interdependent relationships of hydrology, geology, geochemistry, biology, climatology, land use and socio-economic issues. In studies completed in 26 areas, selenium is the trace element found most often at elevated concentrations in water, bottom material and biota. Boron, arsenic, mercury and pesticide residues have also been found at elevated levels in some areas. Bioaccumulation of constituents associated with irrigation drainage is common. As the world experiences an explosive population growth, particularly in poorer countries, demands for food production from marginal, submarginal and newly irrigated soils are likely to cause severe adverse environmental impacts from allocation of limited water resources and contamination from irrigation drainwater. Cultivated marginal land is highly susceptible to degradation from soil erosion, salinization and waterlogging, not withstanding release of contaminants from application of irrigation water.     

Cognitive‐affective stress propensity: a field study

A cognitive‐affective stress propensity model was examined using field study data. Structural equation models analyses tested hypothesized and alternate models to determine their goodness‐of‐fit with the data. The results supported a direct relationship between stress propensity and strain, and an indirect, mediated relationship between stress propensity and strain through a subjective stress construct. In addition, stress propensity was found to moderate the relationships of experienced negative affect with somatic and with psychological strain, and with one of three measures of subjective stress. Implications of the results for research and practice are discussed. Copyright © 1999 John Wiley & Sons, Ltd.