No-policy greenhouse gas emission scenarios: revisiting IPCC 1992

A new set of no-policy global greenhouse gas (GHG) emission scenarios was developed using the atmospheric stabilization framework, the same modeling tool that was used to generate the IS92 emission scenarios for the Intergovernmental Panel on Climate Change. Revised assumptions about population and economic growth, combined with updated information on changes in renewable energy supply, the efficiency of energy generation and other factors resulted in changes in GHG emission profiles over the next century, which led to an increase in the estimated global average temperature change as compared to the IS92 scenarios. Model results indicate that the largest increase in emissions, which led to a temperature increase of about 3.4°C by 2100 (relative to 1990), can be expected when a rapid increase in the GNP per capita levels of the non-OECD countries is combined with a low availability of solar/wind and biomass energy resources and slow energy efficiency improvements. The smallest increase in emissions and temperature by 2100 (about 2.5°C) occurred when a relatively slow increase in the GNP per capita in the non-OECD countries was combined with a high availability of renewable energy resources and rapid energy efficiency improvements.     

First-trimester maternal serum unconjugated oestriol and alpha-fetoprotein in fetal Down's syndrome

Maternal sera (MS) taken from 1396 women prior to chorionic villus sampling at 9–12 menstrual weeks were assayed for unconjugated oestriol (uE3) and alpha-fetoprotein (AFP). Median levels increased by 41 and 26 per cent per week respectively in normal pregnancies. There were 32 pregnancies with a chromosome abnormality. The median MS uE3 and AFP were 0.73 and 0.75 multiples of the median (MoM) respectively in the ten cases of Down's syndrome (DS) but not decreased in the other abnormalities. These results suggest that both uE3 and AFP may be useful in identifying DS in the first trimester. Additional prospective studies are needed to confirm these findings.     

Sacrococcygeal teratoma: Prenatal diagnosis with elevated alphafetoprotein and acetylcholinesterase in amniotic fluid

A sacrococcygeal teratoma was suspected by ultrasound examination at 24 weeks gestation. The amniotic fluid alphafetoprotein was markedly elevated, as was maternal serum AFP. Gel electrophoresis of amniotic fluid showed an acetylcholinesterase band. Labour began at 25 weeks gestation and the chromosomally normal male fetus was found to have a sacrococcygeal teratoma equal to three-quarters of the weight of the fetus.     

Prenatal diagnosis of Huntington's disease (HD): Experiences with six cases and PCR

In the course of a 2-year predictive testing programme for Huntington's disease (HD), six couples from a total of 52 applicants requested prenatal testing. In each case, the pregnancy was in the first or second trimester when the couples were referred for DNA diagnosis. In five cases, exclusion testing was offered; in one case, a person at risk with an increased risk of being a gene carrier requested prenatal diagnosis. In all cases, informative markers for prenatal testing could be determined. Whenever possible, the newer technique of polymerase chain reaction (PCR) for D4S125 was applied to perform rapid prenatal diagnosis. Two couples withdrew before chorionic villus sampling was undertaken; prenatal diagnosis was completed in the remaining four cases. After exclusion testing, two pregnancies were determined to have an increased risk and two fetuses to have a low risk of being HD gene carriers.     

Racial differences in maternal serum human chorionic gonadotropin and unconjugated oestriol levels

We assayed maternal serum samples from 134 black and 268 white women from 16 to 18 weeks of gestation for intact human chorionic gonadotropin (hCG), and unconjugated oestriol (uE3). Serum from women with high ( ⩾ 2·5 MOMs) or low (risk for Down syndrome ⩾ 1/365) maternal serum alpha-fetoprotein (MSAFP) levels were excluded. After correcting for maternal weight, we found that median hCG levels were 16 per cent higher in black women but uE3 levels were not significantly different. These results confirm three other studies for hCG and one study for uE3. Corrections are recommended for both maternal serum hCG and AFP before calculating the risk for Down syndrome in black women.     

Soluble and insoluble fractions of heavy metals in wet and dry atmospheric depositions in Bologna,Italy

Atmospheric depositions were collected monthly using a modified wet and dry sampler (dry deposition was collected on a water surface) located in Bologna, a northern Italian urban area, to evaluate the impact of airborne heavy metals on the local pollution load. Wet deposition samples were filtered and heavy metal contents in soluble and insoluble fractions were determined. The same procedure was applied to the water samples which collected dry deposition. The entire procedure was tested using a certified reference material (CRM), which provided satisfying recovery results. The percentage of heavy metal soluble fraction in dry deposition was generally lower than in wet one; Cd, V, Cu and Zn showed a higher average solubility than Cr, Ni and Pb both in wet and dry deposition. Factor analysis, after a varimax rotation of principal components, suggested possible anthropogenic sources which explain different metal deposition patterns. This data analysis also allowed to distinguish different clusters formed by monthly fluxes of heavy metals.     

Accumulation and elimination of C-PCBs by daphnia magna straus 1820

The accumulation of chlorinated biphenyls in shows a tendency to increase with decreasing water solubility. The depuration times of PCBs from daphnia depend on the temperature of the test water and possibly on the water solubility of the substance. The water solubilities of 2,2′-dichlorobiphenyl, 2,5,4′-trichlorobiphenyl, 2,4,6,2′-tetrachlorobiphenyl and 2,4,6,2′,4′-pentachlorobiphenyl have been determined using ¹⁴C-labelled substances.     

Ecological aspects of transformation in Poland's agriculture based on the Wielkopolska Region

Transformation in Polish agriculture initiated by political changes in the 1990s brought about essential variations in the structure of agricultural land use. The share of cereals in cropping patterns increased, while fodder plants decreased. In addition, the level of mineral fertilization was reduced. In livestock production animal stock showed a sharp fall, which led to a decreased load of organic fertilization. The changes in cropping pattern and lower fertilization rates resulted in a decrease in the organic matter level in soils, which may impair soil quality status. These phenomena were strongly manifested in the Wielkopolska Region mainly because of the prevalence of light soils in this area, from which nutrients are readily washed out to groundwaters. It was found that many of the negative aspects of these changes in the agricultural landscape can be mitigated by establishing shelterbelts. We conclude that shelterbeds are especially effective in the control of nutrient output from a watershed.     

Correlations between toxic Pb effects and production of Pb-induced thiol peptides in the microalga Stichococcus bacillaris

Comparing Pb toxicity to the green alga Stichococcus bacillaris and production of Pb-induced thiol peptides in 24-h exposed cells made it possible to show the level of these peptides to reflect Pb availability to algal cells. LC-ESI/MS analysis of these peptides confirmed that they are phytochelatins PC2-PC4 and their des-Gly derivatives. Studies were carried out at environmentally relevant pH values (5-8.5) and various concentrations of hardness cations (Ca, Mg) and orthophosphate: (0-0.1 mM), chloride (0-100 mM), citrate (0-1 mM), and humic acids (0-10 mg/l). It has been stated, on the basis of the level of Pb-induced thiol peptides, that Pb availability to algae changed significantly within the range of the pH values studied, and was limited in the presence of calcium and of some complexing ligands like orthophosphate, chloride and citrate; it did not decrease in the presence of magnesium or humic acid.     

The changes in common carp blood after short-term zinc exposure

Blood zinc level, hematological parameters and blood cell morphology were evaluated in common carp immediately after 3 h exposure to 20 mg dm(-3) of zinc (Zn0), and in 24, 48 and 96 hours after the end of it (Zn24, Zn48, Zn96). Blood zinc level in the non-exposed fish was 8 mg dm(-3), reached a maximum of 20 mg dm(-3) in Zn48, while it dropped to 9 mg dm(-3) in Zn96. Zinc caused a stress reaction in fish indicated by an increase in hematocrit value in Zn0, and elevated plasma glucose level and trombocytosis which persisted until the end of the experiment. Zinc-exposed fish showed an increased frequency of abnormal erythrocytes, and a compensatory release of immature erythrocytes to the blood stream. In zinc-treated fish, leukocyte count initially increased and subsequently decreased significantly below the control level due to a drop in lymphocyte number. Lymphocyte viability was reduced, and abnormal lymphocytes appeared. A decreased count of juvenile neutrophiles, and reduced phagocyte activity also occurred. The results indicate possible zinc-induced disturbances in both specific and non-specific immune mechanisms.