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Current accounts of spatial cognition and human-object interaction suggest that the representation of peripersonal space depends on an action-specific system that remaps its representation according to action requirements. Here we demonstrate that this mechanism is sensitive to knowledge about properties of objects. In two experiments we explored the interaction between physical distance and object attributes (functionality, desirability, graspability, etc.) through a reaching estimation task in which participants indicated if objects were near enough to be reached. Using both a real and a cutting-edge digital scenario, we demonstrate that perceived reaching distance is influenced by ease of grasp and the affective valence of an object. Objects with a positive affective valence tend to be perceived reachable at locations at which neutral or negative objects are perceived as non-reachable. In addition to this, reaction time to distant (non-reachable) positive objects suggests a bias to perceive positive objects as closer than negative and neutral objects (exp. 2). These results highlight the importance of the affective valence of objects in the action-specific mapping of the peripersonal/extrapersonal space system.  相似文献   

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Metal complexes in cancer therapy have attracted much interest mainly because metals exhibit unique characteristics, such as redox activity, metal-ligand interaction, structure and bonding, Lewis acid properties etc. In 1965, Barnett Rosenberg serendipitously discovered the metal-based compound cisplatin, an outstanding breakthrough in the history of metal-based anticancer complexes and led to a new area of anticancer drug discovery. Many metal-based compounds have been studied for their potential anticancer properties. Some of these compounds have FDA approval for clinical use, while others are now undergoing clinical trials for cancer therapy and detection. In the present study, we have highlighted the primary mode of action of metallic complexes and all FDA-approved/under clinical trial drugs with reference to cancer treatment. This review also focuses on recent progress on metal-based complexes such as platinum, ruthenium, iron, etc. with potential anticancer activities.  相似文献   

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Pathogens may gain a fitness advantage through manipulation of the behaviour of their hosts. Likewise, host behavioural changes can be a defence mechanism, counteracting the impact of pathogens on host fitness. We apply harmonic radar technology to characterize the impact of an emerging pathogen - Nosema ceranae (Microsporidia) - on honeybee (Apis mellifera) flight and orientation performance in the field. Honeybees are the most important commercial pollinators. Emerging diseases have been proposed to play a prominent role in colony decline, partly through sub-lethal behavioural manipulation of their hosts. We found that homing success was significantly reduced in diseased (65.8%) versus healthy foragers (92.5%). Although lost bees had significantly reduced continuous flight times and prolonged resting times, other flight characteristics and navigational abilities showed no significant difference between infected and non-infected bees. Our results suggest that infected bees express normal flight characteristics but are constrained in their homing ability, potentially compromising the colony by reducing its resource inputs, but also counteracting the intra-colony spread of infection. We provide the first high-resolution analysis of sub-lethal effects of an emerging disease on insect flight behaviour. The potential causes and the implications for both host and parasite are discussed.  相似文献   

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I Told You So     
《CMAJ》1970,102(4):423
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The Pampas is a biologically rich South American biome, but is poorly represented in phylogeographic studies. While the Pleistocene glacial cycles may have affected the evolutionary history of species distributed in forested biomes, little is known about their effects on the habitats that remained stable through glacial cycles. The South American Pampas have been covered by grasslands during both glacial and interglacial periods and therefore represent an interesting system to test whether the genetic structure in such environments is less pronounced. In this study, we sampled Pampean populations of Homonota uruguayensis from Southern Brazil and Uruguay to assess the tempo and mode of population divergence, using both morphological measurements and molecular markers. Our results indicate that, in spite of its narrow geographic distribution, populations of H. uruguayensis show high levels of genetic structure. We found four major well-supported mtDNA clades with strong geographic associations. Estimates of their divergence times fell between 3.16 and 1.82 million years before the present. Populations from the central portion of the species distribution, on the border between Uruguay and Brazil, have high genetic diversity and may have undergone a population expansion approximately 250,000 years before the present. The high degree of genetic structure is reflected in the analyses of morphological characters, and most individuals could be correctly assigned to their parental population based on morphology alone. Finally, we discuss the biogeographic and conservation implications of these findings.  相似文献   

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1. After ion exchange chromatographic separation, liver prolidase exhibits two isoforms (prolidase I and II). 2. The activity of both was explored in human and rat tissues, and in normal and cytolytic human plasma. 3. The activity of prolidase I, eluted at the lowest ionic strength, was stimulated by 24 hr of preincubation with 1 mM MnCl2, but prolidase II activity was strongly inhibited by this long preincubation. In both normal and cytolytic human plasma, chromatographic separation also disclosed that only prolidase I activity was present. 4. This isoform displayed properties resembling those of liver and kidney prolidase I. 5. To explain the absence of prolidase II activity from the plasma, we tested the possibility that its tissue distribution differed. 6. However, this was not substantiated by the distribution found, or by the location, molecular weight and behavior of human liver prolidase II after neuraminidase treatment. 7. We also explored the hypothesis that plasma proteins inhibit prolidase II activity, and found that albumin almost abolished this activity after 6 hr incubation.  相似文献   

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In species in which males defend territories for breeding, males may differ in territorial behavior; alternative behaviors among territorial males are not well understood. In our long‐term study of partially‐migratory song sparrows, we have observed that most territorial males establish territories before females begin nesting and remain site‐faithful both within and between breeding seasons; however, some males establish territories later in the season (late establishers) and/or change territory locations either within or between seasons (movers). Whether late establishment or moving are equally successful strategies for territory defense, or best‐of‐bad‐job options, is not known. Here, we compare the frequencies of these behaviors to demographic variables over a 9‐yr period and compare lifetime tenure and early season nesting success for males who differ in site fidelity and timing of territory establishment. Across years, late establishing was negatively correlated with the return rate of previously territorial males; moving was positively correlated with the number of occupied territories at the start of the breeding season (territory density). While moving was independent of number of years on territory, late territory establishment only occurred in a male’s first year as a territory holder. Of 88 males, 25% established their first territory late, primarily in undefended space; 31% moved. Late and early establishers did not differ in lifetime tenure; movers, however, had longer lifetime tenure than site‐faithful males. Among early establishers, movers and non‐movers did not differ in the number of successful early nests/year or number of young fledged/year; among late establishers, however, movers had significantly higher early nesting success by both measures. Late establishers who moved had higher early season nesting success and higher early season nesting success/year than site‐faithful early establishers. Thus, individual variation in the timing of territory establishment and site fidelity may be facultative alternative territorial strategies.  相似文献   

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The ability to empathize with other people is a critical component of human social relationships. Empathic processing varies across the human population, however it is currently unclear how personality traits are associated with empathic processing. This study was designed to test the hypothesis that specific personality traits are associated with behavioral and biological indicators of improved empathy. Extraversion and Agreeableness are personality traits designed to measure individual differences in social-cognitive functioning, however each trait-dimension includes elements that represent interpersonal social functioning and elements that do not represent interpersonal social functioning. We tested the prediction that interpersonal elements of Extraversion (Warmth) and Agreeableness (Altruism) are associated with empathy and non-interpersonal elements of Extraversion and Agreeableness are not associated with empathy. We quantified empathic processing behaviorally (empathic accuracy task using video vignettes) and within the brain (fMRI and an emotional perspective taking task) in 50 healthy subjects. Converging evidence shows that highly warm and altruistic people are well skilled in recognizing the emotional states of other people and exhibit greater activity in brain regions important for empathy (temporoparietal junction and medial prefrontal cortex) during emotional perspective taking. A mediation analysis further supported the association between warm-altruistic personality and empathic processing; indicating that one reason why highly warm-altruistic individuals may be skilled empathizers is that they engage the temporoparietal junction and medial prefrontal cortex more. Together, these findings advance the way the behavioral and neural basis of empathy is understood and demonstrates the efficacy of personality scales to measure individual differences in interpersonal social function.  相似文献   

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How early (EADs) and delayed afterdepolarizations (DADs) overcome electrotonic source-sink mismatches in tissue to trigger premature ventricular complexes remains incompletely understood. To study this question, we used a rabbit ventricular action potential model to simulate tissues in which a central area of contiguous myocytes susceptible to EADs or DADs was surrounded by unsusceptible tissue. In 1D tissue with normal longitudinal conduction velocity (0.55 m/s), the numbers of contiguous susceptible myocytes required for an EAD and a barely suprathreshold DAD to trigger a propagating action potential were 70 and 80, respectively. In 2D tissue, these numbers increased to 6940 and 7854, and in 3D tissue to 696,910 and 817,280. These numbers were significantly decreased by reduced gap junction conductance, simulated fibrosis, reduced repolarization reserve and heart failure electrical remodeling. In conclusion, the source-sink mismatch in well-coupled cardiac tissue powerfully protects the heart from arrhythmias due to sporadic afterdepolarizations. Structural and electrophysiological remodeling decrease these numbers significantly but still require synchronization mechanisms for EADs and DADs to overcome the robust protective effects of source-sink mismatch.  相似文献   

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昂立一号(R)优菌多颗粒人群试食研究   总被引:1,自引:0,他引:1  
昂立一号(R)优菌多颗粒是"昂立一号"家庭新成员,其人群试食研究结果表明,昂立一号(R)优菌多颗粒在短时间(4 d)内就能显著改善食欲、胃肠道及代谢排便功能,随着服用时间的延长,改善作用越强;20 d服用后可极显著地提高人体肠道菌群中的益生菌(双歧杆菌和乳杆菌)数量,却极显著地抑制肠道有害菌产气荚膜梭菌数量,可调节人体肠道菌群平衡,腹泻便秘双重调节,促进肠道健康.  相似文献   

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