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91.
92.
ABSTRACT.
- 1 Body orientation and wing tilting in Hipparchia semele (L.) have been explained previously both by the need for shadow-minimization (crypsis hypothesis) and by the need to regulate body temperature (thermoregulation hypothesis).
- 2 This study tests the thermoregulation hypothesis by quantifying butterfly orientation in relation to sun position, using vector analysis, and correlating the data with ambient temperature and time of day.
- 3 During sunshine, Graylings tend to present a maximal wing area to the sun's rays when the ambient temperature is relatively low, and a minimal area when it is high ('sunning’and‘heat-avoiding’positions respectively).
- 4 On cool sunny days, butterflies adopt sunning positions throughout the day, whereas on warm sunny days they adopt sunning positions during the outlying periods and heat-avoiding positions in the middle period of the day. Correlations between wing exposure and both ambient temperature and time of day are statistically significant for warm sunny days.
- 5 During overcast weather, butterfly orientation is very variable and possibly random.
- 6 Analysis of sunny day data supports the thermoregulation hypothesis. This is discussed in relation to other known types of thermoregulatory behaviour observed in this species: stilting, shade-seeking, ground-hugging and shivering.
- 7 Conversely, the results do not support the crypsis hypothesis.
93.
Water Transport in Isolated Maize Roots 总被引:3,自引:0,他引:3
A simple model has been devised which predicts the concentration,Cxs, of salt (e.g. KCl) in the exudate from isolated roots asa function of the salt concentration, C0s, in the medium. Thechief assumption, made in deriving the relationship betweenCxs and C05, is that the exudation of water, J, from the rootsconsists of two components (one being osmotic, Ø, inorigin and the other, Ø0, flowing in the absence of anosmotic gradient). The exudation of salt, Js, calculated asJ Cxs, was found to be dependent on C0s. Our investigationson maize roots were concerned with estimations of Lp and Øvand determinations of Cxs as a function of C0s. Satisfactoryagreement between prediction and experiment was found in thesepreliminary studies. It is considered that water movement inisolated roots can be explained by a simple osmotic model withthe additional possibility that a relatively small non-osmoticwater flow occurs. 相似文献
94.
Structural complexes in the squid giant axon membrane sensitive to ionic concentrations and cardiac glycosides
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Giant nerve fibers of squid Sepioteuthis sepioidea were incubated for 10 min in artificial sea water (ASW) under control conditions, in the absence of various ions, and in the presence of cardiac glycosides. The nerve fibers were fixed in OsO4 and embedded in Epon, and structural complexes along the axolemma were studied. 相似文献
95.
Gert Kwakkel Carel GM Meskers Erwin E van Wegen Guus J Lankhorst Alexander CH Geurts Annet A van Kuijk Eline Lindeman Anne Visser-Meily Erwin de Vlugt J Hans Arendzen 《BMC neurology》2008,8(1):49
Background
Main claims of the literature are that functional recovery of the paretic upper limb is mainly defined within the first month post stroke and that rehabilitation services should preferably be applied intensively and in a task-oriented way within this particular time window. EXplaining PLastICITy after stroke (acronym EXPLICIT-stroke) aims to explore the underlying mechanisms of post stroke upper limb recovery. Two randomized single blinded trials form the core of the programme, investigating the effects of early modified Constraint-Induced Movement Therapy (modified CIMT) and EMG-triggered Neuro-Muscular Stimulation (EMG-NMS) in patients with respectively a favourable or poor probability for recovery of dexterity. 相似文献96.
Arvind K Awasthi GM Nagaraja GV Naik Sriramana Kanginakudru K Thangavelu Javaregowda Nagaraju 《BMC genetics》2004,5(1):1
Background
The genus Morus, known as mulberry, is a dioecious and cross-pollinating plant that is the sole food for the domesticated silkworm, Bombyx mori. Traditional methods using morphological traits for classification are largely unsuccessful in establishing the diversity and relationships among different mulberry species because of environmental influence on traits of interest. As a more robust alternative, PCR based marker assays including RAPD and ISSR were employed to study the genetic diversity and interrelationships among twelve domesticated and three wild mulberry species. 相似文献97.
Harriëtte Riese Tanja GM Vrijkotte Piet Meijer Cees Kluft Eco JC de Geus 《BMC cardiovascular disorders》2002,2(1):9-12
Background
Serum C-reactive protein (CRP) has been identified in prospective epidemiological research as an independent risk marker for cardiovascular disease. In this paper, short-term biological variation of CRP is documented and a strategy to test the reliability of a single CRP sample is proposed. 相似文献98.
The relationship between perception of tenderness and chewing activity was explored using the Time-Intensity measurement of perception and electromyographic measurements of masseter muscle movement. Semitendinosus muscles from eight treatments of forage fed beef were evaluated by nine individuals. The Time-Intensity parameters of Area Under the Curve and Decrease Area were the most useful for treatment separation based on tenderness. Information was obtained from the electromyogram regarding the number of chews, time to chew and mastication rate. However, more work with EMG measurements is required to accurately study the effect of masticatory patterns on tenderness perception. 相似文献
99.
100.
Foliar elemental composition of European forest tree species associated with evolutionary traits and present environmental and competitive conditions
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