Conservative maternal care in an iteroparous mammal: a resource allocation experiment

When resources are limited, life history theory predicts a trade-off between growth, reproduction and survival. In summer, lactating females of temperate large herbivores such as the white-tailed deer (Odocoileus virginianus) normally have access to abundant forage but also face the high energetic needs of lactation and recovery from winter mass loss. At high population density, however, females may face a trade-off between allocating resources for maintenance and for reproduction. To simulate the effects of increased intra-specific competition at high density, we measured for 2 years how an experimental food restriction of approximately 20% affected current reproduction and body mass changes of adult females and their fawns during the fawning and lactation periods. Fawn survival decreased 35%, and fawn growth decreased 26% in the food-restricted treatment. There was no effect of food restriction on female mass. Irrespective of treatment, however, lactating females gained 30 g/day less than non-lactating females, and females that had weaned a fawn the previous year gained 20 g/day less than females that had not. We conclude that when resources were scarce, females adopted a conservative strategy favouring their own survival, mass recovery and future reproductive potential over their current reproduction, probably to maximise their lifetime reproductive success.     

Pheromones inBlattella germanica andBlaberus craniifer (Blaberoidea): Glandular source,morphology and analyses of pheromonally released behaviours

Females ofBlattella germanica andBlaberus craniifer produce a volatile sex pheromone attractive at a distance for conspecific males. During the emission of the pheromone, females ofB. craniifer adopt a typical calling posture; we never observe such a stance inB. germanica females. For both species, the glandular structures responsible for pheromonal production are located on the female pygidium. InB. germanica, the thickness of the glandular epithelium is clearly correlated with the attractiveness of females, being maximum for 13 day old females. The functions of the pygidial glands are discussed in both species.     

Land district,ecophysiographic units and areas: The landscape mapping of the Ministère des Ressources naturelles du Québec

In 1985, the Ministère des Ressources naturelles established a Forest Ecological Survey Program for Southern Québec. One component of the program was the mapping of land districts, which provide a physiographically-based territorial reference system. The land districts have an average surface area of between 100 and 300 sq km. Since its inception, the department has further refined the methodologies and standardized the results. The current methodologies are based on inventory and analysis of the geographical distribution of permanent environmental components (e.g., relief, surficial deposits, geology, hydrography). The products include 1:50 000 maps of surficial deposits, 1:250 000 maps of the land districts and physiographic systems, and a computerized data bank.To date, 500 000 km square have been covered, and the estimated completion date for the work is 1999. To facilitate use of the products and to encourage the development of new applications, a guide for forest managers and other users has been recently published. The guide assists with forest management planning strategies based upon the physical environment, in particular the production and use of interpretation grids and maps. The products of the mapping process are, for many regions of Southern Québec, the only source of information on permanent environmental components.Currently, the Ministère des Ressources naturelles is planning to develop landscape maps of Southern Québec which identify ecophysiographic units (1:1 250 000) and ecophysiographic areas (1:2 500 000). These maps are based upon the integration of critical physiographic features and the synthesis of land regions.     

Maternal serum alpha fetoprotein in monozygotic and dizygotic twin pregnancies

Maternal serum α-fetoprotein (MSAFP) values in the second trimester have been related to pregnancy outcome for 100 normal twin pairs, 42 monozygous (MZ) and 58 dizygous (DZ), liveborn after 28 weeks gestation. The median MSAFP value was 1.9 multiples of the median value (MOM) for uncomplicated singleton pregnancies. Both very low and very high MSAFP values were associated with twins of low birthweight. MSAFP values were higher in MZ than DZ twin pregnancies particularly those with dizygotes of like-sex. This effect was even more marked when only dichorionic like-sex twin pairs were compared.     

Inhibitory effect of arachidonic acid on venom acetylcholinesterase

The venom of krait (Bungarus sindanus), an Elapidae snake, contains high level of acetylcholinesterase (AChE) activity. The effect of arachidonic acid on krait (Bungarus sindanus) venom AChE (acetylcholine hydrolase, EC 3.1.1.7) was studied using kinetic methods. This study evaluated for the first time whether arachidonic acid acts as potential AChE inhibitor of krait venom. Kinetic studies, using Line-Weaver Burk and Dixon plots, indicated that the inhibition produced by arachidonic acid was non-competitive, i.e., both k_m and V _max fell with increase in the concentration of arachidonic acid. The concentration of arachidonic acid required to inhibit 50% of enzymatic activity was found to be 1.9?µM while the inhibitory constant (K_i ) was 1.4?µM. The present results suggest that essential fatty acid (arachidonic acid) may also be used as an inhibitor of snake venom AChE.     

Ocean acidification and temperature rise: effects on calcification during early development of the cuttlefish Sepia officinalis

This study investigated the effects of seawater pH (i.e., 8.10, 7.85 and 7.60) and temperature (16 and 19 °C) on (a) the abiotic conditions in the fluid surrounding the embryo (viz. the perivitelline fluid), (b) growth, development and (c) cuttlebone calcification of embryonic and juvenile stages of the cephalopod Sepia officinalis. Egg swelling increased in response to acidification or warming, leading to an increase in egg surface while the interactive effects suggested a limited plasticity of the swelling modulation. Embryos experienced elevated pCO₂ conditions in the perivitelline fluid (>3-fold higher pCO₂ than that of ambient seawater), rendering the medium under-saturated even under ambient conditions. The growth of both embryos and juveniles was unaffected by pH, whereas ⁴⁵Ca incorporation in cuttlebone increased significantly with decreasing pH at both temperatures. This phenomenon of hypercalcification is limited to only a number of animals but does not guarantee functional performance and calls for better mechanistic understanding of calcification processes.     

A Two-Sector Model of Economic Growth with Endogenous Technical Change and Pollution Abatement

Environmental Modeling & Assessment - We provide insights into the relationships between technological development, economic growth, and pollution accumulation using a two-sector model of...     

Future forest landscapes of the Carpathians: vegetation and carbon dynamics under climate change

Regional Environmental Change - Climate change will alter forest ecosystems and their provisioning of services. Forests in the Carpathian Mountains store high amounts of carbon and provide...     

Ozone production from Grenoble city during the August 2003 heat wave

The heat wave from 1 to 16 August 2003 is considered in the city of Grenoble (French Alps). The modelling system (PREVALP) is based on several models operating on nested domains: MM5 for dynamics, CHIMERE for chemistry (18 km and 6 km grid size) and METPHOMOD for both dynamics and chemistry (2 km grid size). The analysis of the results shows that during the heat wave, the mixing layer is thicker, up to 3500 m agl, hence inducing transport of ozone to high altitude. Two regimes were diagnosed: (1) a freely developing convective layer, (2) a layer trapped under south wind which makes ozone precursors accumulate in the city. Local ozone production is estimated to be 40% of the plume maximum in case (2) and only 30% in case (1). Sensitivity analysis by step increase for temperature at the boundary of the inner domain shows the non-linearity of the response; in this case most of the effect comes from chemistry. By changing biogenic emission significant changes are observed in restricted areas.     

Exposure assessment of French women and their newborn to brominated flame retardants: determination of tri- to deca- polybromodiphenylethers (PBDE) in maternal adipose tissue, serum, breast milk and cord serum

In the frame of a French monitoring program, tri- to deca- polybromodiphenylethers (PBDE) have been measured in maternal and cord serum, adipose tissue, and breast milk samples, collected from 93 volunteer women during caesarean deliveries. The seven major tri- to heptaBDE (BDE-28, 47, 99, 100, 153, 154, and 183) were detected in adipose tissue and breast milk with cumulated median values of 2.59 and 2.51 ng g⁻¹ l w. Nine highly brominated octa- to decaBDE (BDE-196, 197, 201, 202, 203, 206, 207, 208 and 209) was performed in the same samples, with cumulated median values of 2.73 and 3.39 ng g⁻¹ l w in adipose tissue and breast milk, respectively. At this opposite, median levels of octa- to decaBDE in maternal and cord serum appeared significantly higher than the levels of tri- to heptaBDE in the same matrices, i.e. 8.85 and 12.34 versus 0.98 and 0.69 ng g⁻¹ l w, respectively.