The Arctic sea butterfly<Emphasis Type="Italic"> Limacina helicina</Emphasis>: lipids and life strategy

The sea butterfly Limacina helicina was collected from May to September 2001 in Kongsfjorden, Spitsbergen, to investigate population structure and body and lipid composition with regard to life cycle and reproductive strategy. Veligers and juveniles were only found in late autumn and spring, whereas females occurred from July to September. The size of the females increased until mid-August and decreased in September. Dry and lipid mass were closely related to size; dry mass increased exponentially and lipids linearly with size. The lipid content was highest in veligers (31.5% of dry mass) and juveniles (23.6%) but low in females (<10%). Phospholipids were the dominating lipid class followed by triacylglycerols. Females, veligers, and egg ribbons, all from September, were richest in phospholipids. Juveniles contained the highest amounts of triacylglycerols, whereas females had low levels in July and the beginning of August. In mid-August, levels of triacylglycerols were variable and higher. This suggests that females were in their main spawning period and the high variability in triacylglycerols points to different stages within the spawning cycle. Enhanced amounts of free fatty acids in females from July may be related to gonad development. The 16:1(n-7) fatty acid was more dominant in spring whereas 18:4(n-3) increased in summer and autumn, which reflects a change in diet from diatom-dominated food items in spring to dinoflagellates in summer/autumn. Small amounts of long-chain monounsaturated fatty acids suggest ingestion of copepods, and the fatty acid composition of veligers feeding on particulate matter. L. helicina has a one-year life cycle with peak spawning in August and over-winters as veligers that may grow to juveniles during the winter period. They metamorphose into juveniles during spring, develop to males in early summer, and mature into females in July and August.Communicated by M. Kühl, Helsingør     

Tire blow-outs and motorway accidents

During the period from 1996 to 2002, 60,397 vehicles were involved in crashes with property damage and/or injury on a French motorway network of 2000 km. It was observed that 6.7% of these accidents involved tire blow-outs. In 87% of cases, only one vehicle was involved in the accident. Tire blow-outs occurred in 6.5% of cars that represented more than 80% of the vehicles involved in crashes. The occurrence of this phenomenon is very high for vans (22%), though it concerns trucks less (2.5%). The proportion of tire blow-outs decreased from 1997, when it was 8.0%, to 5.9% in 2002. However, two main facts require examination: (1) On inter-urban motorways, crashes involving blow-outs of rear tires occur four times more frequently than for blow-outs of front tires. (2) The frequency of tire blow-outs is especially high for vans, and almost always involves rear tires. This higher frequency for rear tires is the result of two phenomena, which are indistinguishable given the data available: firstly, a four-wheel vehicle is more difficult to control if a blow-out occurs on a rear tire (confirmed experimentally); secondly, rear tires may be in poor condition more often than front tires, and so more prone to blow-outs. Consequently, users are strongly recommended to install the best tires on rear wheels. In practice, if only the front tires are replaced, which often occurs because they tend to be worn out more quickly than the rear ones (especially for front wheel drive vehicles), it is necessary to move the rear tires to the front and fit the new ones on the rear wheels. Very interesting technological developments are in progress that should reduce the number of tire blow-outs. However, considering the time necessary to renew the number of cars on the roads, this very simple and inexpensive recommendation should apply to all cars and especially to vans.     

Three Ways To Be a Saber-Toothed Cat

 Saber-toothed carnivores, until now, have been divided into two groups: scimitar-toothed cats with shorter, coarsely serrated canines coupled with long legs for fast running, and dirk-toothed cats with more elongate, finely serrated canines coupled to short legs built for power rather than speed. In the Pleistocene of North America, as in Europe, the scimitar-cat was Homotherium; the North American dirk-tooth was Smilodon. We now describe a new sabercat from the Early Pleistocene of Florida, combining the scimitar-tooth canine with the short, massive limbs of a dirk-tooth predator. This presents a third way to construct a saber-toothed carnivore. Received: 6 February 1999 / Accepted in revised from: 20 October 1999     

Transfer of powders into flammable solvents overview of explosion hazards and preventive measures

This paper evaluates and analyses the explosion hazards associated with transfer operations of powders into large containers, hoppers and reactors, which may also contain flammable solvent vapours. The formation and characteristics of explosive atmospheres and the occurrence of process inherent ignition sources, such as static electricity are described. The most commonly applied preventive measures and technical equipment are outlined and discussed including their advantages and disadvantages.     

Multisensor monitoring of plume dynamics in the northwestern Mediterranean Sea

We used data from various space-borne sensors to monitor the marine ecosystem in the northwestern Mediterranean Sea, at the Costa Dorada, between the City of Barcelona and the estuary of the river Ebro. The aim of this study was to demonstrate that the combination of different remote sensing data (acquired at different electromagnetic frequencies) allows for an improved monitoring system, in particular for a better monitoring of the marine ecosystem and, hence, a better coastal zone management. We present remote sensing data acquired by the Synthetic Aperture Radar (SAR) and the Along-Track Scanning Radiometer (ATSR) aboard the Second European Remote Sensing Satellite (ERS-2), and by the Sea-viewing Wide Field-of-view Sensor (Sea WiFS) on the SeaStar satellite. By combining the different data we are able to overcome specific drawbacks of the single sensors, like an insufficient temporal coverage, or a strong dependence on weather and daylight conditions. Within the study area two main features have been selected as examples, which are well visible on many of the analysed images. The first one exhibits a higher load of chlorophyll-a and surface-active compounds and a lower sea surface temperature (SST), which is likely to be caused by the plume of the river Llobregat, southwest of Barcelona. It can clearly be seen from the imagery how the river plume is driven along the coast by the local currents. The second feature can be related to cooling water being released from a nuclear power plant and causing turbulence in the water body, which in turn gives rise to signatures visible on the ERS-SAR imagery.     

Trade''s Dynamic Solutions to Transboundary Pollution

This study develops a differential game to examine the effects of trade liberalization on transboundary water pollution. Water pollution is due to wastewater emissions from countries in a shared waterway along the U.S.–Mexico border with available data of pollution abatement costs, public health damages, and trade benefits. Noncooperative and cooperative games are examined with changes in trade policy and public health damages. Results show trade liberalization leads Mexico to curtail pollution in both games. Cooperation and trade liberalization limit emissions from both countries and curtail strategic behavior of the United States from Mexico's pollution control efforts in the noncooperative game.     

Duplication of chromosome 2 in association with ventriculomegaly — a case report

This is a case report of the prenatal diagnosis of a de novo interstitial duplication of chromosome 2 (46,XX,dup(2)(p13p21) de novo) with an associated phenotypic abnormality. This chromosomal duplication is rare, only one has previously been described prenatally. Postnatal reports of similar duplications in this region have described associated dysmorphic features and significant neurodevelopmental delay. In our case, the only ultrasound finding was moderately severe ventriculomegaly. At post-mortem, ventriculomegaly was confirmed and there was associated macrocephaly (head circumference above the 97th centile) with no dysmorphic features seen. Copyright © 2001 John Wiley & Sons, Ltd.     

First-trimester maternal serum human thyroid-stimulating hormone in chromosomally normal and Down syndrome pregnancies

Maternal serum human thyroid-stimulating hormone (TSH) levels were investigated in chromosomally normal and Down syndrome pregnancies to determine whether TSH can be used as a marker for Down syndrome in the first trimester. Measurements were conducted on stored serum samples collected from 23 Down syndrome pregnancies and 115 unaffected pregnancies before chorionic villus sampling (CVS), between 9 and 11 completed weeks of pregnancy. The samples were matched for gestational age, maternal age, maternal weight and duration of storage of the serum sample. Maternal TSH concentration was slightly decreased in Down syndrome pregnancies, with a median of 0.84 multiples of the median (MoM). Maternal serum human chorionic gonadotropin (hCG) concentration was slightly elevated in Down syndrome pregnancies, with a median of 1.03 MoM. Both differences were not significant applying matched rank analysis (p=0.50 for TSH and p=0.43 for hCG). The association between TSH and hCG in unaffected pregnancies was also measured. The Spearman correlation coefficient between TSH and hCG was −0.21 which was statistically significant (p=0.02, 95% confidence interval −0.38 to −0.03). However, it was concluded that TSH is not a useful marker for distinguishing Down syndrome-affected pregnancies from normal pregnancies in the first trimester. Copyright © 2001 John Wiley & Sons, Ltd.     

Changes in the spermatophoric plasma during spermatophore development and during the spermatophoric reaction in the giant octopus of the north pacific,Octopus dofleini martini

Concentrations of Na, K, Cl, Ca and Mg were measured in the spermatophoric plasma and certain other body fluids of Octopus dofleini martini. The most striking change associated with maturation and passage of the spermatophore in the male reproductive tract, was a decline in the concentration of NaCl in the spermatophoric plasma. This was completely reversed during the spermatophoric reaction owing to influx of salt from the seawater. The outer tunic of a spermatophore undergoing spermatophoric reaction is also permeable to other substances. It allows an influx of inorganic phosphate and glucose, and an efflux of organically bound nitrogen, carbohydrate and aminosugar.