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排序方式: 共有163条查询结果,搜索用时 15 毫秒
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Raquel Mendonça Sarian Kosten Gissell Lacerot Néstor Mazzeo Fábio Roland Jean P. Ometto Eduardo Alonso Paz Claudia Petean Bove Norma Catarina Bueno José Henrique C. Gomes Marten Scheffer 《Hydrobiologia》2013,710(1):205-218
Even though the suitability of macrophytes to act as a carbon source to food webs has been questioned by some studies, some others indicate that macrophyte-derived carbon may play an important role in the trophic transfer of organic matter in the food web of shallow lakes. To evaluate the importance of macrophytes to food webs, we collected primary producers—macrophytes and periphyton—and consumers from 19 South American shallow lakes and analyzed their carbon stable isotopes composition (δ13C). Despite the diversity of inorganic carbon sources available in our study lakes, the macrophytes’ δ13C signatures showed a clear bimodal distribution: 13C-depleted and 13C-enriched, averaging at ?27.2 and ?13.5‰, respectively. We argue that the use of either CO2 or HCO3 ? by the macrophytes largely caused the bimodal pattern in δ13C signals. The contribution of carbon from macrophytes to the lake’s food webs was not straightforward in most of the lakes because the macrophytes’ isotopic composition was quite similar to the isotopic composition of periphyton, phytoplankton, and terrestrial carbon. However, in some lakes where the macrophytes had a distinct isotopic signature, our data suggest that macrophytes can represent an important carbon source to shallow lake food webs. 相似文献
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B. de Sá-Haiad C. A. Torres V. H. R. de Abreu M. R. Gonçalves C. B. F. Mendonça L. D. R. de Santiago-Fernandes C. P. Bove V. Gonçalves-Esteves 《Plant Systematics and Evolution》2010,290(1-4):141-149
The family Podostemaceae is exceptional among angiosperms because of its uncommon biology and morphology, the absence of double fertilisation and endosperm, and the obscure distinction between root, stem, and leaf. The highly modified morphology produced by reductions and specialisations is reflected in the multiple positions that the Podostemaceae has occupied in different classification systems. In the family, structural studies are mainly related to the vegetative body. In the genus Podostemum, structural data are related to the development and embryology of Podostemum ceratophyllum Michx., which, with P. weddellianum, has pre-anthesis cleistogamy. P. weddellianum is analysed for the first time with regard to floral structure and palynology. The presence of silica in the spathella, the apical septum in the ovary, dyads and pseudomonads, unimodal embryo sac and chasmogamous flowers with the possibility of self-pollination contribute to the characterisation of the Podostemoideae and the search for relationships among Podostemaceae and the clusioids. 相似文献
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Luigino Calzetta Piero Rossi Pierluigi Bove Pietro Alfonsi Luigi Bonizzi Paola Roncada Roberta Bernardini Edoardo Ricciardi Mauro Montuori Elena Pistocchini Paolo Mauti Maurizio Mattei 《Experimental Animals》2014,63(4):423-433
Nowadays, because of increasing employment of swine for experimental studies and medical
training, it is hopeful to investigate novel and effective anaesthetic protocols for
preserving the animal welfare in medical investigation and concurrently improving the
quality of research. Therefore, the aim of this study was to investigate a novel and
effective anaesthetic protocol in swine undergoing major surgery, by translating know-how
of combined anaesthesia from human protocols. Seven landrace swine were anaesthetized for
three hours by a combined trial anaesthetic protocol (sedation: medetomidine,
acepromazine, atropine and tramadol; induction: propofol, medetomidine and acepromazine;
anaesthesia: isofluorane, propofol, medetomidine and acepromazine) and both clinical and
haemodynamic parameters were compared with those of five swine anaesthetized with a
control protocol (sedation: diazepam, ketamine and atropina; induction: diazepam and
ketamine; anaesthesia: isofluorane). Both cardiac frequency (CF) and mean blood pressure
(MBP) were significantly (P<0.05) more stable in trial protocol (CF:
78.3 ± 4.6-81.1 ± 5, MBP: 63.9 ± 10.7-96.4 ± 13.0) compared to control protocol (CF: 93.7
± 5.5-102.5 ± 8.5, MBP: 71.0 ± 6.6-108.7 ± 7.2). The body temperature remained stable in
trial protocol (°C: 36.9 ± 0.7-37.2 ± 0.3) compared to control anaesthesia (°C: 36.4 ±
0.3-37.3 ± 0.2, P<0.05). Haematosis improved undergoing combined
anaesthesia (+2%, P<0.05) whereas did not change in control animals.
There were no differences in respiratory rate between trial and control protocols. This
study demonstrates that the proposed balanced intravenous-inhalant protocol permits to
carry out a very effective, stable and safe anaesthesia in swine undergoing deep
anaesthesia. 相似文献
118.
Riley B. Bove Claudia R. Valeggia Peter T. Ellison 《Human nature (Hawthorne, N.Y.)》2002,13(4):457-472
In this paper we outline the activities of young girls in a Toba community of northern Argentina and examine the effect of
girl helpers on time allocation of nursing women. Activity budgets were obtained for 41 girls aged 3 to 15 using spot observations.
Girls spent substantial portions of observations engaged in helping behaviors. Individual values varied with age, anthropometric
characteristics, and birth order. Activity budgets of 21 nursing women were obtained through focal observation sessions. Women
living in households with girls aged 7 to 15 allocated 17% less time to domestic work and 9% more time to socializing during
afternoon observation sessions. For nursing women in this community, direct childcare (provided by the infant’s own mother)
seemed to be a priority. Living with a girl helper did not have any measurable effect on the frequency or duration of nursing,
or on the time that women spent caring for their infants. Based on these findings, hypotheses are outlined for future work
on the effect of girl helpers on women’s fertility.
Research for this project was funded by the Nestlé Foundation, the Harvard Anthropology Goelet Fund, and the Harvard College
Research Program. Eduardo Fernandez-Duque commented on an early draft of this paper.
Riley Bove (A.B., Harvard, 1998) is a research associate in the Department of Anthropology at Harvard University with research
interests in intergenerational female networks and polygyny as a social mediator of women’s health (esp. urban, African).
Claudia Valeggia (Ph.D., U.C. Davis, 1996) is a postdoctoral fellow in the Department of Anthropology at Harvard University
with research interests in reproductive ecology and ethnopediatry. Peter Ellison (Ph.D., Harvard, 1983) is a professor of
anthropology and director of the Reproductive Ecology Laboratory at Harvard University. He is the author of On Fertile Ground: Ecology, Evolution and Human Reproduction (Harvard University Press, 2001). 相似文献
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Schaumburg F Köck R Friedrich AW Soulanoudjingar S Ngoa UA von Eiff C Issifou S Kremsner PG Herrmann M Peters G Becker K 《PLoS neglected tropical diseases》2011,5(5):e1150