Winter-spring essential reorganization of cell proliferation in the digestive tract epithelia in the mussel Crenomytilus grayanus

A study of the seasonal dynamics of cell proliferation in the digestive tract epithelia of the mussel Crenomytilus grayanus (Bivalvia) collected in the Sea of Japan between 1971 and 1984 revealed two opposite states so far unknown for marine molluscan tissues: proliferative resting in winter and a following outburst of cell division in spring. In winter and early spring (at water temperatures below or near 0°C), mitotic figures in the lining epithelia of labial palps and intestine strongly reduced in number and later almost disappeared (February-March); DNA-synthesizing cells in these epithelia on thymidine radioautographs became sparse and only a restricted number of new cells entered the cell cycle. A proliferation block was relieved at the beginning of April (at a temperature of 2 to 4°C): an initiation of a many-fold increase in the mitotic index and some increase in the ³H-T-labelled nuclei index and their advance to the maximum in late April to May (up to more than 0.2 and 5 to 6%, accordingly) were found. In late spring (at temperatures of 5 to 10°C), a striking rise in the number of cells entering the cell cycle was observed with a probable acceleration of the cycle proper. Both seasonal states of cell proliferation — a deep depression and outburst, established in the winter-spring period are interpreted as essential events in the life cycle of the mussel studied.     

Dilated coronary sinus in prenatal echocardiography; identification,associations and outcome

The dilated coronary sinus (DCS) has only recently been clearly visualised in the fetus due to progress in prenatal echography. This is a retrospective study of 22 fetuses presenting with DCS revealed by prenatal echography. We report the circumstances leading to the detection of a DCS and the neonatal outcome of these fetuses. The coronary sinus was defined as dilated depending on its visualisation in cross-section from the ‘4 chamber’ view, as well as a pseudo inter-atrial septal defect from a more posterior view. In each case the gestational age, circumstances of detection, associated anomalies and postnatal outcome are reported. The circumstances were: evaluation of a clearly identified DCS in four cases and during detailed fetal echocardiography because of suspected congenital heart disease in 18 cases. Five cases were associated with a cardiac anomaly, three with an extracardiac anomaly, six with both cardiac and extracardiac anomaly and eight were isolated. Postnatal outcome was related to the associated anomaly. In conclusion, it is important that the echography image be correctly interpreted, as a DCS often implies possible associated defects and therefore affects prognosis. When not associated with other anomalies this condition is not considered serious. Copyright © 2002 John Wiley & Sons, Ltd.     

Representativeness and Efficiency of Bird and Insect Conservation in Norwegian Boreal Forest Reserves

I quantified local species richness of birds in different forest types and of beetles in spruce forests at different altitudes. In both cases I quantified timber production as a measure of land acquisition cost and used the ratio between the species richness and timber production as a measure of conservation cost-efficiency. I found a positive correlation between timber production and local species richness of birds as well as beetles, indicating that the forests most valuable for forestry are also the ones most valuable for biodiversity conservation. I used different selection procedures for combining sites in a reserve network to find the minimum set of sites that included all vulnerable species. The minimum set of sites for birds was 30% spruce forest, 30% pine forest, and 40% broad-leaved forest (the three main forest types). The minimum set of sites for the beetles was uniformly distributed along the altitudinal gradient. Both minimum sets were most cost-efficient for species conservation. I suggest that equal coverage of different productivity classes is more efficient for optimizing biodiversity conservation than over-representing low productivity sites. Less than 1% of Norwegian boreal forests have been protected as nature reserves. The reserve network is fairly representative with respect to altitude, but it is seriously skewed toward low productivity sites. The current network is suboptimal with respect to forest type representativeness, species protection, and cost-efficiency. This is a result of an inefficient strategy of selecting reserve sites and an unfortunate combination of selection criteria.     

Field-scale rotary kiln incineration: Oxygen responses at the kiln,afterburner, and stack

There currently exists a need for better characterization and simulation of the processes that occur during the incineration of hazardous wastes in the environment of a rotary kiln. Addressing this need, a comprehensive research program was formed with the goal of developing a rudimentary predictive capability for rotary kiln incineration of hazardous wastes. This comprehensive program is headed by Louisiana State University and includes interaction with the University of Utah and also various industrial participants. Such cooperation allows use of laboratory, pilot, and field scale equipment. While laboratory scale experiments provide the necessary decoupling of complex phenomena and a high degree of experimental control, and pilot scale studies provide more realism at the expense of experimental control, the problems of scale-up make generalization of results to field scale units very tenuous. The unique aspect of the LSU program is the coupling of the laboratory and pilot scale units with afield scale unit in order to overcome these generalizations. In this study, plastic packs containing a mixture of toluene and sorbent were fed to a field-scale rotary kiln incinerator at a rate of one pack every 10 minutes. Selected continuous gas samples and temperatures were obtained from the exit of the rotary kiln, from the afterburner, and from the stack. These measurements were obtained during various operating conditions. These data provide, for the first time, an ability to compare conditions in the kiln to simultaneous conditions in the afterburner and stack. This paper outlines several new experimental features of our field-scale tests conducted in October 1990. Oxygen responses from the kiln, the afterburner, and the stack are compared during various operating conditions.     

In vitro brain acetylcholinesterase response among three inbred strains of mice to monocrotophos.

The strain differences in the neurotoxic potential of monocrotophos (MCP) were assessed by determining the inhibition of brain acetylcholinesterase (AChE) in BALB/cAnN, DBA/2J and C57BL/6J in vitro. MCP being a competitive inhibitor for AChE, alters the Km values widely among these inbred strains. Comparatively least alterations in Km were found in BALB/cAnN and maximum in DBA/2J. Based on the Ki values DBA/2J was found to be the most sensitive strain to MCP inhibition followed by C57BL/6J and BALB/cAnN.     

Flame Propagation Across Gelled Alkane-In-Water Emulsions

Flame propagation rates were measured for flames spreading across surfaces of gel-like alkane-in-water emulsions. A long, slender, water-cooled trough was used to contain the mixtures. Abrupt changes in the flame propagation velocities - of nearly two orders of magnitude - were observed to occur near ‘critical’ concentrations of certain alkane/water mixtures. Four alkanes were used - pentane, hexane, heptane, and octane - and fuel rich emulsions (in which water was the continuous phase) were employed. The ability of the aqueous phase of the emulsion to inhibit the release of fuel into the vapor phase plays an important role in the observed behavior. That is, the rate at which fuel can diffuse through both the emulsion and the thin liquid layers that reside on it, is an essential kinetic aspect of the phenomena which determine the flame propagation rate across gelled alkane-in-water emulsions.     

Assessment of Soil Cover Degradation and Desertification in Northern Lowland Dagestan

New principles of the assessment of soil cover degradation and desertification, the scale and intensity of destructive processes manifestation are determined.     

Presence–Absence versus Abundance Data for Monitoring Threatened Species

Abstract:  Effective detection of population trend is crucial for managing threatened species. Little theory exists, however, to assist managers in choosing the most cost-effective monitoring techniques for diagnosing trend. We present a framework for determining the optimal monitoring strategy by simulating a manager collecting data on a declining species, the Chestnut-rumped Hylacola ( Hylacola pyrrhopygia parkeri ), to determine whether the species should be listed under the IUCN (World Conservation Union) Red List. We compared the efficiencies of two strategies for detecting trend, abundance, and presence–absence surveys, under financial constraints. One might expect the abundance surveys to be superior under all circumstances because more information is collected at each site. Nevertheless, the presence–absence data can be collected at more sites because the surveyor is not obliged to spend a fixed amount of time at each site. The optimal strategy for monitoring was very dependent on the budget available. Under some circumstances, presence–absence surveys outperformed abundance surveys for diagnosing the IUCN Red List categories cost-effectively. Abundance surveys were best if the species was expected to be recorded more than 16 times/year; otherwise, presence–absence surveys were best. The relationship between the strategies we investigated is likely to be relevant for many comparisons of presence–absence or abundance data. Managers of any cryptic or low-density species who hope to maximize their success of estimating trend should find an application for our results.