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111.
MATHIEU LEBLOND CHRISTIAN DUSSAULT JEAN-PIERRE OUELLET MARIUS POULIN RÉHAUME COURTOIS JACQUES FORTIN 《The Journal of wildlife management》2007,71(7):2304-2310
ABSTRACT Wildlife-vehicle collisions cause numerous human fatalities and injuries, and generate considerable expenses in property damage each year. Certain characteristics of the road and its surroundings are known to have an impact on collision probability. Roadside salt pools increase the risk of collision by attracting moose (Alces alces) to the side of the road. In the Laurentides Wildlife Reserve of Québec, Canada, roadside salt pools were drained and filled with rocks to deter moose from drinking. We surveyed 12 roadside salt pools during 3 consecutive summers (2003–2005) from mid-May to mid-August. Seven salt pools were managed in autumn 2004, and 5 pools were left untreated. We equipped all 12 sites with electronic apparatus that allowed us to detect moose attendance and study their behavior. We also measured physical, chemical, and environmental characteristics of these pools and other unvisited pools in order to correlate moose attendance with specific habitat criteria. We found that moose mostly attended roadside salt pools from mid-June to mid-July, with a decrease in August. Moose attendance was significantly correlated with visual obstruction toward the road and water availability. Management of the pools caused a decrease in mean length of time moose spent at them. Number of visits decreased significantly at night (by 90%), which was when most visits occurred, but not during the day. The proposed management practice prevented all visiting moose from drinking brackish water. These results suggest that moose should eventually lose interest in treated salt pools, therefore decreasing the risk of moose-vehicle collisions on the road. 相似文献
112.
MEENAKSHI VENUGOPAL JAMES M. JAMISON JACQUES GILLOTEAUX JOHN A. KOCH MARCIA SUMMERS JASON HOKE COLLEEN SOWICK JACK L. SUMMERS 《Cell biology international》1996,20(12):787-797
Vitamins C, K3(VC, VK3) and a VC/VK3combination with a VC:VK3ratio of 100:1 were assayed for their antitumour activity against two human prostatic carcinoma cell lines. Co-administration of the vitamins enhanced the antitumour activity 5- to 20-fold even with a 1 h exposure time. While exogenous catalase destroyed the antitumour activity, hydrogen peroxide-induced lipid peroxidation was negligible. Analysis of cellular ATP and thiol levels as well as DNA and protein synthesis revealed: a transient increase in ATP production, a decrease in DNA synthesis, an increase in protein synthesis and a decrease in thiol levels. These results suggested that the increased cytotoxicity of the vitamin combination was due to redox cycling and increased oxidative stress. 相似文献
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114.
1. Conifer‐feeding budworms (Choristoneura) hibernate in sheltered locations on their host trees from late summer of 1 year to spring of the next. During this period, they do not feed but rely on sustenance provided in the egg. Overwinter survival is dependent on the rate of consumption of these limited reserves. 2. A process model was developed that quantifies the relationship between the rate of consumption and survival at variable temperatures and exposure times for western spruce budworm. The model supported physiological evidence that warm weather conditions early in the diapause period have a dominant influence on overwinter survival. Output compared favourably with field observations of poorer budworm survival at lower elevations where late‐summer and autumn temperatures were warmer compared to those overwintering at cooler, higher elevations. 3. Field experiments demonstrated these weather‐dependent rates of survival were modulated significantly by the degree of shelter experienced by hibernating budworms. 4. Dissection of whole trees harbouring overwintering western spruce budworms showed a significant portion of the population had travelled a considerable distance from the periphery of the tree canopy where eggs were laid to overwinter successfully on the tree bole where sheltered niches are common. 5. Thus, budworms will travel relatively long distances and risk increased mortality during this dispersal to find adequate shelter to overwinter. 相似文献
115.
MARIA-MARCELA POVEDA MARIE-CLAUDE SOUQUAL MARIE-THÉRÈSE FAUVEL JACQUES GAMISANS THIERRY GAUQUELIN 《Botanical journal of the Linnean Society. Linnean Society of London》2002,140(2):165-168
The cuticular wax composition of leaves has been analysed in three western European populations (Corsica, central Pyrenees, northern Alps) of Juniperus communis var. saxatilis Pall. (= J. nana Willd., nom illeg.) and in one population of J. communis L. var. depressa Pursh. from North America (Sierra Nevada). Gas chromatography shows the presence of 13 alkanes in all samples ranging from C23 to C35 with important intraspecific polymorphism in alkane content. The dominant alkanes range from C33 to C35 . Alkanes C21 and C22 were found only in Corsica and Sierra Nevada populations. Canonical discriminant analysis separated the J. communis L. var. depressa Pursh. of the population of Sierra Nevada from other populations of J. communis var. saxatilis Pall. on the basis of their higher C31 content and the constant presence of C21 and C22 alkanes. J. communis var. saxatilis Pall. populations from the Pyrenees are close to northern Alps populations characterized by high concentrations of C33 , C34 and C35 alkanes. This paper confirms the existence of Juniperus var. saxatilis Pall. in the Pyrenees (France). © The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 140 , 165–168. 相似文献
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117.
JACQUES MÉDUS 《Lethaia: An International Journal of Palaeontology and Stratigraphy》1983,16(4):265-271
Upper Cretaceous pollen grains with a thick wall (exine) and sometimes protruding apertures, included in the Normapolles Pflug, are considered from a functional point of view. Because of the high development of compression-resistance features correlative with a high protection of the gametophyte, an entomophilic phase is supposed in the dissemination of some types, but anemophily appears to have been a developmental trend of apertural specialization for others. As these functional features are characteristic of the outer part of the wall (the sexine), the tetrahedral morphology of the inner part (the nexine) and the lack of evidence that it influenced the whole adaptive system suggest that angiospermic constraints have acted first at a pteridophytic stage. 相似文献
118.
JACQUES BOHATIER 《The Journal of eukaryotic microbiology》1979,26(3):404-414
SYNOPSIS Cortical events occurring in the course of regeneration in Condylostoma magnum (Spiegel) were studied by electron microscopy. The zone of regeneration is very rich in vacuoles and small vesicles formed from the plasma membrane. Multiplication of kinetosomes starts on the left side of kineties in the V-shaped left ventral area, normally implicated in stomatogenesis, at the level of the anterior kinetosomes of the somatic pairs. The proliferation proceeds by the appearance of young kinetosomes most often orthogonal to the old ones. This process of multiplication is very rapid and terminates in the formation of an “anarchic field” in which one observes that: (a) the newly formed kinetosomes do not possess all the associated postciliary fibers; and (b) when these fibers are detected, the kinetosomes are not in the same orientation. Differentiation of the adoral organelles takes place in the left part of the field (left primordium) by an alignment of the kinetosomes into 2 rows for each organelle (oriented perpendicularly to the antero-posterior axis of the ciliate), of which only one has the postciliary fibers. Ciliatogenesis occurs in numerous kinetosomes of the anarchic field; in certain kinetosomes it is achieved at the onset of their arrangement into organelles and is concomitant with growth of the nematodesmata. The 3rd (anterior) row of the organelles, the interkinetosomal desmata, and connections among neighboring organelles appear only secondarily. Differentiation of the paroral cilia occurs later. It takes place in the interior of the primordium, whose organization is primarily anarchic, and is accompanied by a progressive resorption of the major part of the newly formed kineties. Numerous kinetosomes of the right field have the associated postciliary fibers, which are not found at the level of the regenerated “polystichomonad” (paroral organization characteristic of C. magnum). Finally, the formation of new kinetosomes within a somatic kinety at the time of its elongation is described. 相似文献
119.
Lectins as Markers of Human Epidermal Cell Differentiation 总被引:7,自引:0,他引:7
A. REANO M. FAURE Y. JACQUES U. REICHERT H. SCHAEFER J. THIVOLET 《Differentiation; research in biological diversity》1982,22(1-3):205-210
The expression of sugar residues on human epidermal cells was investigated by means of lectin binding, as a way of determining membrane structural changes occurring during the differentiation of the epidermis. Fourteen lectins of different sugar specificity were conjugated with fluorescein isothiocyanate (FITC-lectins) and tested in fluorescence microscopy on frozen sections of normal human epidermis. In parallel, FITC-lectins were tested on psoriatic-involved epidermis to visualize differences in the expression of sugar residues that might occur during abnormal epidermal differentiation. No labelling could be obtained with lectins from Bandeira simplicifolia I, Dolichos biflorus, Limulus polyhemus, Tetragonolobus purpureas, Ulex europeus I , and Triticum vulgaris (group 1 lectins). A "pemphigus-like" intercellular labelling of the whole epidermis, except the stratum corneum, was obtained with lectins from Canavalia ensiformis, Maclura pomifera, Phaseolus vulgaris , and Ricinus communis I (group 2 lectins). A selective intercellular labelling of the stratum spinosum and the stratum granulosum was seen in normal epidermis with lectins from Arachis hypogaea, Glycine max, Helix pomatia , and Sophora japonica (group 3 lectins). In psoriatic epidermis, not only the basal cell layer, but also cells from the adjacent lower stratum spinosum were found to be negative, using FITC-lectins of group 3. These data indicate that the expression of lectin binding sites in normal epidermis differs according to the maturation of the cell from the basal cell to the more mature keratinocyte in the stratum granulosum. They suggest that lectins may be used as markers of epidermal cells in various stages of normal and abnormal differentiation. 相似文献
120.
MARIE-HÉLÈNE BRÉ JEFFREY DIAMOND ROGER JACQUES 《The Journal of eukaryotic microbiology》1975,22(3):432-434
SYNOPSIS. Deprived of vitamin B12 , Euglena gracilis strain Z ceases to divide which we believe to be a function of the light regime: division inhibition occurs more quickly in continuous light than in alternating (6L : 6D) light and not at all in total darkness. This phenomenon is dependent on the carbon source; cells grown in glutamate-malate medium do not divide regardless of the culture conditions while dl -lactate as carbon source permits growth in darkness in the absence of B12 . Conditions which lead to an increased O2 or decreased CO2 tension in the medium, such as agitation in darkness or incubation in red or white light, result in inhibition of division. This inhibition can be reversed by re-transferring the cells to still culture in the dark or, in the case of light-induced blockage, by the addition of DCMU. 相似文献