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1.
Conium maculatum, a Eurasian weed naturalized in North America, contains high concentrations of piperidine alkaloids that act as chemical defenses against herbivores. C. maculatum was largely free from herbivory in the United States, until approximately 30 yr ago, when it was reassociated via accidental introduction with a monophagous European herbivore, the oecophorid caterpillar Agonopterix alstroemeriana. At present, A. alstroemeriana is found in a continuum of reassociation time and intensities with C. maculatum across the continent; in the Pacific Northwest, A. alstroemeriana can cause severe damage, resulting in some cases in complete defoliation. Studies in biological control and invasion biology have yet to determine whether plants reassociated with a significant herbivore from the area of indigeneity increase their chemical defense investment in areas of introduction. In this study, we compared three locations in the United States (New York, Washington, and Illinois) where C. maculatum experiences different levels of herbivory by A. alstroemeriana to determine the association between the intensity of the interaction, as measured by damage, and chemical defense production. Total alkaloid production in C. maculatum was positively correlated with A. alstroemeriana herbivory levels: plants from New York and Washington, with higher herbivory levels, invested two and four times more N to alkaloid synthesis than did plants from Illinois. Individual plants with lower concentrations of alkaloids from a single location in Illinois experienced more damage by A. alstroemeriana, indicative of a preference on the part of the insect for plants with less chemical defense. These results suggest that A. alstroemeriana may act either as a selective agent or inducing agent for C. maculatum and increase its toxicity in its introduced range. 相似文献
2.
Sixth instars of the parsnip webworm, Depressaria pastinacella, orient by olfaction to bud, male flowers, and female flowers of their primary host plant, Pastinaca sativa. Because octyl acetate and octyl butyrate are characteristic of tissues consumed by the sixth instar, we investigated the influence of these esters on webworm feeding behavior and chemo-orientation. Although octyl acetate and octyl butyrate are feeding deterrents, and octyl butyrate is an olfactory repellent, octyl acetate serves as an olfactory attractant. In olfactometers, webworms do not show a preference when given a choice between octyl acetate and host plant tissues. These findings suggest that octyl acetate is a sufficient cue for olfactory orientation. Such behavior may explain differences in the relative abundance of these esters observed among populations of wild parsnip under differential selection pressure from these insects. 相似文献
3.
4.
Early hormones have been hypothesized to influence both sexual orientation and related childhood sex-typed behaviors. This study examined hormonal influences on activity and playmate preferences in children with congenital adrenal hyperplasia (CAH) aged 2.5–12 yrs (24 girls, 19 boys) and their relatives (16 girls, 25 boys). CAH girls preferred boys' toys and activities. They also had greater preference for boy playmates than controls, but this was largely attributable to 4 girls. CAH boys did not differ significantly from controls. Activity and playmate preferences were not related. It was concluded that early androgen has a major effect on childhood activity preferences but only a weak influence on playmate preferences; sex segregation does not arise from sex-typed activity preferences; activity and playmate preferences may be differently predictive of sexual orientation; and hormonal influences on sexual orientation are likely to be complex. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
5.
Berenbaum Howard; Oltmanns Thomas F.; Gottesman Irving I. 《Canadian Metallurgical Quarterly》1988,97(1):108
The points raised by Matthysse and Holzman (1988) center around two major issues: (a) how to measure thought disorder and (b) how to think about its relation to schizophrenia and the etiology of that disorder. Some of the limitations that Matthysse and Holzman (1988) note appear to be based on misunderstandings of our (Berenbaum, Oltmanns, & Gottesman, 1985) methods, particularly what we were measuring and why we were measuring it. We, too, were surprised to find no evidence that these fundamental aspects of formal thought disorder are heritable. We do not know whether other anomalies of verbal communication are heritable. The issue must be resolved through further empirical investigation. Finally, some aspects of the model proposed by Matthysse and Holzman are open to serious question. The assumption that there is no relation between severity of illness and the underlying liability that precipitated the illness is most likely incorrect. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
6.
We tested the hypothesis that sex differences in spatial ability and emotional perception are due to sex differences in intrahemispheric organization of the right hemisphere. If the right hemisphere is differently organized by sex-primarily specialized for spatial ability in men, but primarily specialized for emotional perception in women-then there should be a negative correlation between spatial ability and emotional perception within sex, and the greatest disparity between abilities should be found in people with characteristic arousal of the right hemisphere. Undergraduate men (N = 86) and women (N = 132) completed tests of Mental Rotation, Surface Development, Profile of Nonverbal Sensitivity, Progressive Matrices, and Chimeric Faces. Although the expected pattern of sex differences was observed, there was no evidence for the hypothesized negative correlation between spatial ability and emotional perception, even after statistical control of general intelligence. 相似文献
7.
Examined somatic androgyny and IQ in 3 longitudinal studies, conducted at the Institute of Human Development, in order to determine how robust the androgyny–ability relationships reported in recent studies are, and whether these relationships are found after sexual maturity is attained. Results do not reveal significant relationships between androgyny and abilities at either adolescence or middle adulthood, although trends are in the predicted directions. There were no systematic findings from analyses separating aspects of somatic androgyny that are more likely to be primarily under control of the sex hormones as opposed to those that are probably subject to other genetic and/or environmental influences. These results are discussed in terms of factors that might moderate androgyny–ability relationships. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
8.
Alexandra?Bartole-Scott Andrea?Berenbaum Rui?Resendes Ian?MannersEmail author Gerald?Dubois Keith?G.?Balmain 《Journal of Inorganic and Organometallic Polymers and Materials》2005,15(4):485-495
Polyferrocenylsilanes [Fe(η-C5H4)2SiMePh]
n
(3) and [Fe(η-C5H4)2SiMe2]
n
(4) were prepared by transition metal-catalyzed ring-opening polymerization (ROP) and thin films of these materials were studied to investigate their potential utility as protective charge migration coatings for dielectrics. Films (
15 μm) of 3 or 4 cast from a concentrated toluene solution coated on Mylar did not experience any arc discharging when exposed to a beam of low energy (20 keV) electrons for a 1 h time period. In order to further investigate the charge migration properties of polyferrocenylsilanes, thick shapes and films of 3 were prepared by mold-extrusion and solution-casting onto a Teflon substrate, respectively. Charge accumulation measurements on 3 using a nonintrusive electrostatic probe showed that even after a 1 h exposure to a 25 keV electron flux, no appreciable charge accumulation existed. The direction of current flow was explored by constructing a device consisting of a film (thickness ca. 100–130 μm) of polymer 3 coating a layer of copper. When positioned beneath a circular mask and exposed to a low energy electron flux (5–25 keV), measurements of the current at the surface of the polymer film either exposed to or not exposed to the electron flux were not significantly different, and the current recorded from the bare copper connection to the ground was significantly (100–1000 times) higher. Although the mechanism of charge migration in polyferrocenylsilanes is not fully understood, these experiments indicated it may arise from a conduction mechanism, however electron scattering may also be involved.Dedicated to Professor Richard J. Puddephatt in recognition of his
outstanding and scholarly contributions to chemistry. 相似文献
9.
Debbie L Maclellan Shawna Berenbaum 《Revue canadienne de la pratique et de la recherche en diététique》2006,67(3):119-124
PURPOSE: The concept of "client-centredness" was explored within a nutrition counselling relationship. METHODS: A two-round reactive Delphi survey was used. The first survey was sent to 65 Dietitians of Canada members who indicated in the member database that they had advanced counselling skills. Following analysis of the data, the second-round questionnaire was developed and sent to participants with a report of the first-round results. Analysis of the second-round survey indicated that participants' responses had remained stable, and the Delphi survey was terminated. RESULTS: Participants agreed that most of the issues identified in the Delphi questionnaire should be included in a client-centred approach to practice; however, when participants were asked about their experience in these areas, median responses and/ or the interquartile ranges changed, indicating some difficulty in implementing the client-centred approach. Comments also indicated that the reality of their workplaces did not allow participants to be as client-centred as they thought they should be, and suggested that the concept of "client-centredness" is not universally understood by dietitians. CONCLUSION: If a client-centred approach to practice is truly important, we need to start a dialogue within the profession to gain a deeper understanding of what this means and how it can be implemented. 相似文献
10.
F Berenbaum G Thomas S Poiraudeau G Béréziat MT Corvol J Masliah 《Canadian Metallurgical Quarterly》1994,340(1-2):51-55
Interleukin 1 beta was found to stimulate arachidonic acid release, and the synthesis and secretion of type II phospholipase A2 by rabbit articular chondrocytes in vitro. Interleukin 1 beta had no effect on the level of cytosolic phospholipase A2 mRNA. Insulin-like growth factors, which help stabilize the cartilage matrix, reduced the effect of interleukin 1 beta on type II phospholipase A2 activity and mRNA level, and decreased the Interleukin 1 beta-stimulated arachidonic acid release to the basal values. This suggests that type II phospholipase A2 plays a key role in arachidonic acid release from rabbit articular chondrocytes and that insulin-like growth factors counteract the effect of interleukin 1 beta. They may therefore be considered as potential antiinflammatory agents. 相似文献