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S. C. Thomson 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》1998,353(1375):1595-1606
Speakman and co-workers suggested the diurnal Samoan flying fox, Pteropus samoensis, may be at risk of hyperthermia when flying during the day, particularly at high levels of insolation. We monitored activity of this bat and climate simultaneously at two different sites and four times of year in American Samoa. Flight activity varied significantly with time of day, between days, study sites and seasons. Out of the six data sets collected, the four with the highest mean levels of insolation showed a significant decrease in bat numbers with increasing temperature and sunlight. When each individual activity count was directly compared to the predictions of Speakman and co-workers'' biophysical model, 85 to 95% of bat flight activity was found to be in conditions the model suggested would not pose a risk of hyperthermia. This supports the suggestion that in extreme conditions the animals would not fly as they risked overheating. The 5 to 15% of counts in which animals were seen to fly in conditions the model predicted they should not may be explained by erroneous assumptions underlying the model predictions. 相似文献
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An old adage in anthropology holds that societies perpetuate their moral codes by the manner in which people raise their children, but socialization is far more than the straightforward passing on of culture. Rather, culture acquisition is a highly conflictual process, rich in contested meanings. What other theorists have shown on the level of cultural systems, this analysis intends to show at the level of micro-interactive processes. The article examines Samoan child-rearing routines, subjective reactions to these routines, the manner in which these reactions are in conformity and in resistance to cultural norms, and the discourse through which Samoan society finally strives to temper the resisting subject. By taking the conflictual dimensions of the socialization process into account, the article describes and analyzes indigenous perspectives on Samoan temperament. These perspectives have the potential to reconcile certain vehement disagreements that characterize the ethnography of the self in Samoa. 相似文献
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By extending the work of linguistic anthropologists on indexicality to transnational communities, this article shows how a simple instruction to sit down can be a way of making physically distant worlds emotionally and ethically close. Comparison of the use and context of this expression among Samoan speakers in two communities, a Western Samoan village and a suburban neighborhood in southern California, illustrates the power of language to bridge the gap. Talking space is at the same time a socialization strategy to teach children proper ways of behaving in front of adults and an attempt to provide cultural and socioethical continuity despite the distance between the islands from which immigrant Samoans come and the new environment in which they live and raise their children. 相似文献
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1. Changes in the activity pattern of leech Retzius (R) cells were investigated using intracellular recording. 2. The presence of an after-hyperpolarisation (AHP) is closely related to activity pattern; regular firing being associated with an AHP, bursting with its absence. 3. Increasing external calcium (Cao), cyclic AMP levels or activity of kinase A enhanced the AHP. 4. Bursting was induced by low Cao, EGTA, barium, cobalt or injection of phorbol ester. 5. Reduction of Cao to zero caused long paroxysmal depolarising shifts of potential which could be reversed to bursting by cobalt, IBMX or injection of kinase A catalytic subunit. 6. The possible roles of a calcium-activated potassium channel and protein phosphorylation in regulating the activity of the cell are discussed. 相似文献
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The aqueous extract and the essential oil of Satureja viminea (Lamiaceae) were tested. General physiologic effects were assessed through the Hippocratic screening test. Non fasted female Sprague Dawley rats were utilized and 250, 500, 750 and 1000 mg/kg doses were used. Two animals were used for each dosage level and for the vehicle alone. Exploratory behavior and curiosity were measured using a hole board apparatus and placing non-trained mice on the board and recording the number of holes explored in a 5 minute period. The Boissier chimney test was used to evaluate motor coordination. Muscle strength was assessed through a grasping test where mice were hung by their fore-limbs 40 cm above the base on a horizontal metal stainless bar. In all these tests, 3 groups of 6 albino mice, were treated with 1000 mg/kg of each the essential oil of S. viminea, the vehicle and diazepan (1 mg/kg) as a positive control. Analgesic activity was explored in Sprague-Dawley rats. The tail flick method described by D'Amour and Smith (1941) modified by CYTED was implemented on three groups (6 rats each) of animals treated with, each the essential oil of S. viminea (1000 mg/kg), the vehicle and indomethacine. The test was carried out just before and 30, 60 and 120 min after oral treatment. Peristaltic activity was measured in albino mice, three groups of 6 animals each, treated orally with each the essential oil of S. viminea (1000 mg/kg), the aqueous extract (1000 mg/kg), and the vehicle. The marker used was activated carbon. Animals were sacrificed 30 min after the marker was given and the percent of total small intestine traversed by it was calculated. Also a lethal dose 50 (LD 50) was determined with the Spearman-Karber method. A dose-related spontaneous motor activity reduction was observed. Exploratory behavior and curiosity were diminished. The grasping strength of mice was reduced. A very clear and significant analgesic effect was observed with the oral administration of the essential oil of S. viminea (1000 mg/kg). This effect is compared to that of indomethacine. Intestinal transit and gastric emptying were inhibited by the essential oil. The LD50 of the essential oil of S. viminea is 556.8 mg/kg. 相似文献
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Androphilia refers to sexual attraction to adult males, whereas gynephilia refers to sexual attraction to adult females. Male androphilia is an evolutionary paradox. Its development is at least partially influenced by genetic factors, yet male androphiles exhibit lower reproductive output, thus raising the question of how genetic factors underlying its development persist. The sexual antagonism hypothesis posits that the fitness costs associated with genetic factors underlying male androphilia are offset because these same factors lead to elevated reproduction on the part of the female relatives of androphilic males. Western samples drawn from low fertility populations have yielded inconsistent results when testing this hypothesis. Some studies documented elevated reproduction among the matrilineal female kin of androphilic males, whereas others found such effects in the paternal line. Samoa is a high-fertility population in which individuals reproduce closer to their maximum capacities. This study compared the reproductive output of the paternal and maternal line grandmothers, aunts, and uncles of 86 Samoan androphilic males, known locally as fa'afafine, and 86 Samoan gynephilic males. Reproductive output was elevated in the paternal and maternal line grandmothers, but not aunts or uncles, of fa'afafine. These findings are consistent with the sexual antagonism hypothesis and suggest that male androphilia is associated with elevated reproduction among extended relatives in both the maternal and paternal line. Discussion focuses on how this study, in conjunction with the broader literature, informs various models for the evolution of male androphilia via elevated reproduction on the part of female kin. 相似文献
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The enzyme activity and activation energy of plasma beta-N-acetylhexosaminidase (Hex) was determined in rats whose serotonergic system had been pharmacologically altered. In the group of animals treated with 5-hydroxytryptophan, in the different dissected brain regions (brain stem, cortex and hippocampus) significantly higher levels of serotonin and 5-hydroxyindolacetic acid were found, and significantly lower in the group treated with p-chlorophenylalanine, than in the control group. In the total number of animals studied (n = 21), a statistically significant correlation was found between the plasma concentration of 5-hydroxyindolacetic acid and the levels of this metabolite in the different brain regions (p < 0.001). No significant differences were found for the activity of Hex in the plasma, or for its activation energy, which is a marker of its isoenzyme composition, among the three groups of animals. The results obtained using our experimental model in rats do not confirm the hypothesis of other authors who suggest that the Hex responds secondary to increases or decreases of serotonin turnover, and could be a biological test to monitor the serotonin status in psychiatric patients. 相似文献
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Birth order and male androphilia in Samoan fa'afafine 总被引:1,自引:0,他引:1
Vasey PL VanderLaan DP 《Proceedings. Biological sciences / The Royal Society》2007,274(1616):1437-1442
The manner in which male androphilia is publicly expressed varies cross-culturally. As such, it is unclear whether distinct or common underlying causal processes characterize male androphilia in different cultures. Establishing the existence of cross-cultural universals in male androphilia is one means of ascertaining whether common biological bases underlie this phenomenon despite its culturally distinct forms. The evidence that the number of older biological brothers increases the odds of androphilia in later-born males has been well documented for Western samples (i.e. the fraternal birth order effect); but there is little evidence for this effect in non-Western samples. Here, we compare the birth order of androphilic males (i.e. fa'afafine) and gynephilic males from the politically autonomous Polynesian nation of Independent Samoa. Results indicate that relative to gynephilic males, fa'afafine tend to have more siblings and are generally later born when birth order is quantified using Slater, fraternal and sororal indices. More specifically, fa'afafine tend to have a greater number of older brothers, older sisters and younger brothers. We discuss the observed effects in relation to the differing reproductive patterns exhibited by the mothers of fa'afafine and gynephilic males, and to existing social and biological theories for sexual orientation. 相似文献
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Michaelis M Langer K Arnold S Doerr HW Kreuter J Cinatl J 《Biochemical and biophysical research communications》2004,323(4):1236-1240
The chelating agent diethylenetriaminepentaacetic acid (DTPA) inhibits human cytomegalovirus replication. Since chelating agents are known to exhibit anti-cancer effects, DTPA-induced cytotoxicity was evaluated in breast cancer cells (MCF-7) and neuroblastoma cells (UKF-NB-3). DTPA inhibited cancer cell growth in threefold lower concentrations compared to human foreskin fibroblasts (HFF). Antiviral and anti-cancer activity of chelating agents is caused by intracellular complexation of metal ions. DTPA, an extracellular chelator, was covalently coupled to human serum albumin (HSA) molecules, HSA nanoparticles (HSA-NP), gelatin type B (GelB) molecules, and GelB nanoparticles (GelB-NP) to increase cellular uptake. Coupling of DTPA to drug carrier systems increased its cytotoxic and antiviral activity by 5- to 8-fold. Confocal laser scanning microscope examination revealed uptake of DTPA-HSA-NP in UKF-NB-3 cells and HFF. Therefore, coupling of DTPA to protein-based drug carrier systems increases its antiviral and anti-cancer activity probably by mediating cellular uptake. 相似文献
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A. F. Makarchenko B. A. Roitrub R. S. Zlatin E. D. Genis O. I. Kostyuk 《Neurophysiology》1973,5(1):37-43
The kinetics of cholinesterase activity in the sensomotor cortex, hippocampus, and anterior hypothalamus was determined in 93 rats by an electrometric method using an automatic recording system. The localization of acetylcholinesterase in the cell structures was revealed histochemically. In the control animals acetylcholinesterase was distributed unevenly among these structures. In rats aged 1 month its activity was higher in the sensomotor cortex. At later age periods (6, 12, 24 months) the acetylcholinesterase activity was highest in the posterior hypothalamus. While the unevenness of distribution of this substance continued to be observed, the level of its activity fell with age. A redistribution of acetylcholinesterase activity compared with the control was found 15 min after subcutaneous injection of adrenalin (300 µg/kg). Its activity was maximal in the anterior hypothalamus. The acetycholinesterase activity in all these structures was lowered after subcutaneous injection of chloral hydrate (300 mg/kg). Meanwhile the differences in the character of its distribution between the individual structures disappeared. These results indicate definite correlation between the functional state of the CNS and the distribution of acetylcholinesterase activity in the brain structures studied.A. A. Bogomolets' Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 5, No. 1, pp. 47–53, January–February, 1973. 相似文献
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A. A. Artyukov A. M. Popov A. V. Tsybulsky O. N. Krivoshapko N. V. Polyakova 《Biochemistry (Moscow) Supplemental Series B: Biomedical Chemistry》2013,7(3):237-242
Pharmacological activity of echinochrome A (EchA) alone and in the biologically active additives (BAA) Timarin, administered per os has been investigated in volunteers. Blood hematological, immunological, and biochemical parameters were investigated before and after administration of the substances used. EchA decreased serum glutatione (GSH) and increased catalase activity 1 h after treatment. Later (3 h after administration) catalase activity normalized, while GSH exceeded the initial level. Changes in blood lipids suggest decreased risk of atherogenesis. Changes found in blood sex hormone levels indicate that Timarin may influence sex gland functioning. Changes of hematological and immunological parameters have been interpreted as the result of a mild stressor effect of both EchA alone and in the BAA Timarin increasing adaptation reactivity of the body. 相似文献
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Knab AM Bowen RS Hamilton AT Lightfoot JT 《Journal of biological regulators and homeostatic agents》2012,26(1):119-129
The genetic factors involved in the regulation of physical activity are not well understood. The dopamine system has been implicated in the control of voluntary locomotion and wheel running (WR) in mice and is thus a likely candidate as a genetic/biological system important to the regulation of physical activity. This study evaluated the effects of four different dopaminergic acting drugs on WR in differentially active inbred strains of mice. High active C57L/J (n=7, 3 controls, 4 experimental) and low active C3H/HeJ (n=8, 3 controls, 5 experimental) were analyzed for baseline wheel-running indices of distance (km/day), duration (mins/day), and speed (m/min) for 21 days. Experimental mice received increasing doses over four days of each of the following drugs: SKF 81297 (D1 agonist), SCH 23390 (D1 antagonist), GBR 12783 (DAT inhibitor), and AMPT (tyrosine hydroxylase inhibitor). Each drug dose response treatment was separated by three days of recovery (no drug injections). WR indices were monitored during drug treatments and during drug wash-out phases. SKF 81297 significantly reduced (p=0.0004) WR in the C57L/J mice, but did not affect WR in the C3H/HeJ mice. GBR 12783 significantly increased (p=0.0005) WR in C3H/HeJ mice, but did not affect WR in C57L/J mice. Only duration (not overall WR) was significantly reduced in C57L/J mice in response to SCH 23390 (p=0.003) and AMPT (p=0.043). SCH 23390 (p=0.44) and AMPT (p=0.98) did not significantly affect WR in C3H/HeJ mice. These results suggest that genetic differences in dopamine signaling may play a role in the WR response to dopaminergic-acting drugs in inbred strains of mice. The high activity in the C57L/J strain appears most responsive to D1-like receptor acting drugs, while in the C3H/HeJ strain, dopamine re-uptake appears to have an influence on activity level. 相似文献
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