Structural Constraints on the Performance of Symmetrical Bimanual Movements with Different Amplitudes

1995 ◽  
Vol 48 (3) ◽  
pp. 716-740 ◽  
Author(s):  
Will Spijkers ◽  
Herbert Heuer

In bimanual movements the amplitude of each hand's movement often depends on the concurrent amplitude of the other hand's movement such that both amplitudes become similar (amplitude coupling). We tested the hypothesis that the strength of amplitude coupling depends on the tempo of performance of a movement sequence, a hypothesis based on a model of bimanual coordination that holds that cross-talk occurs at the execution level as well as at the programming level. Subjects performed bimanual periodic arm movements on two digitizers. In nine conditions constant small, constant large, and alternating small and large amplitudes of each arm were orthogonally combined. Overall tempo was varied by instructing subjects to increase the tempo progressively by 10%. Clear tempo-dependent modulations of the amplitude were observed in movements with instructed constant amplitude when the other hand performed alternating amplitudes. The effect of the size of constant-amplitude movements on the mean amplitude of the other hand indicated cross-talk at the execution level. Cross-talk at the programming level was revealed by the dependence of the current amplitude on the change in the amplitude of the other hand in the preceding cycle. Finally, asymmetric cross-manual effects were observed.

2012 ◽  
Vol 602-604 ◽  
pp. 776-780
Author(s):  
Zhi Qiang Li ◽  
Mei Li ◽  
Wei Jia Fan

Poly(3-hydroxybutyrate-co-4-hydroxybutyrate)copolymer [P(3HB-co-4HB)] is a kind of biodegradable high molecular polymer produced by bioaccumulation. Because of the good biodegradability and biocompatibility, P(3HB-co-4HB)s have attracted wide attention . At first, the intrinsic viscosity[η] in good solvent of P(3HB-co-4HB) s with varying contents of 4HB was investigated in different temperature. Second, observed the changes of crystallization gathered state caused by the varying contents of 4HB by polarizing microscope. The results show that to the P(3HB-co-4HB)s in same molecular weight, the intrinsic viscosity[η] in good solvent barely changes when the mole fractions of 4HB increase. On the other hand, the mean square end to end distances[0] of macromolecular flexible chains increase with the mole fractions of 4HB. At the same time, the states of aggregation change from spherulites to dendrites. In this investigation, we discuss the reasons of the differences in depth.


Zoosymposia ◽  
2011 ◽  
Vol 5 (1) ◽  
pp. 143-146 ◽  
Author(s):  
KIMIO HIRABAYASHI ◽  
GORO KIMURA ◽  
EISO INOUE

The species composition and abundance of adult caddisflies attracted to the illuminated showcase of a vending machine set along the middle reaches of the Shinano River were investigated every Sunday night from April to November in 2005 to 2007. A total of 1,405 adult caddisflies was collected during the investigation periods. We identified a total of 13 species belonging to 11 genera of 8 families. The most abundant species was Psychomyia acutipennis (Ulmer 1908) each year. Psychomyia acutipennis adults were collected from mid-May to the beginning of October (the range of mean air temperature was 13.8 to 27.7°C), with its seasonal abundance divided into several peaks, i.e., the end of May, the beginning of June, and the end of August to the beginning of September in both 2006 and 2007. On the other hand, in 2005 when there was no large-scale summer flood and there were no marked abundance peaks. The present study suggests that the mean air temperature and summer floods impacted the seasonal abundance of P. acutipennis adults.


Author(s):  
Kenneth R. Laughery ◽  
David R. Lovvoll ◽  
Michael S. Wogalter

Three studies were carried out to explore how people allocate responsibility for safety during product use. In Study 1 29 consumer products were named and subjects apportioned safety responsibility to the manufacturer, the retailer, the user, and a potentially relevant organization not in the stream of commerce (e.g., FDA, CPSC, Underwriters Laboratories). The mean percent responsibility allocated to these four alternatives was 43%, 9%, 27% and 21% respectively. A significant interaction indicated that the allocation varied across products. In Study 2 safety responsibility for the same products was allocated to the manufacturer, retailer and user, but the “outside” organization was omitted. The mean percent allocated was 51%, 20% and 30% respectively. In this study, additional questions assessed various perceptions of the products and the subject's familiarity with the products. The results indicated that responsibility allocation was a function of perception of product hazardousness; the more hazardous a product is perceived to be, the more responsibility is allocated to the user. Study 3 investigated some of the attributes of high hazard products which are associated with various allocations of product safety. For high hazard products with open and obvious risks (chain saws, cutting torches), more responsibility was allocated to consumers as opposed to manufacturers. On the other hand, for those high hazard products with “hidden” risks (pesticides, antifreeze), manufacturers were typically allocated a much higher degree of responsibility.


1879 ◽  
Vol 25 (109) ◽  
pp. 1-4
Author(s):  
Arthur Mitchell

In the population of Scotch Asylums, there are so few persons below the age of 10 years that, for practical purposes, it may be correctly said there are none. of the general community, on the other hand, 25·6 per cent. are persons below that age. It is clear, therefore, that the death-rate of the population of asylums cannot properly be compared with the death-rate of the general population. To make such a comparison it is necessary to deal only with the deaths occurring among the 74·4 per cent. of the general community who are above the age of 10 years. When this is done, it appears that the mean annual death-rate for the general population is 1·7 per cent. as compared with 8·3 per cent. for the population of asylums. These figures refer to the whole population of asylums, and to the whole of the general population above the age of 10 years; but in order to show the rates at which persons of different ages die in asylums, and the rates at which persons of corresponding ages die in the general community, the following table has been prepared. It is founded on 3,800 deaths occurring during the seven years, 1870–1876, in the Asylums of Scotland, which had a mean population of 6,421 during those years.


1987 ◽  
Vol 57 (4) ◽  
pp. 1033-1049 ◽  
Author(s):  
P. H. Schiller ◽  
J. H. Sandell ◽  
J. H. Maunsell

Rhesus monkeys were trained to make saccadic eye movements to visual targets using detection and discrimination paradigms in which they were required to make a saccade either to a solitary stimulus (detection) or to that same stimulus when it appeared simultaneously with several other stimuli (discrimination). The detection paradigm yielded a bimodal distribution of saccadic latencies with the faster mode peaking around 100 ms (express saccades); the introduction of a pause between the termination of the fixation spot and the onset of the target (gap) increased the frequency of express saccades. The discrimination paradigm, on the other hand, yielded only a unimodal distribution of latencies even when a gap was introduced, and there was no evidence for short-latency "express" saccades. In three monkeys either the frontal eye field or the superior colliculus was ablated unilaterally. Frontal eye field ablation had no discernible long-term effects on the distribution of saccadic latencies in either the detection or discrimination tasks. After unilateral collicular ablation, on the other hand, express saccades obtained in the detection paradigm were eliminated for eye movements contralateral to the lesion, leaving only a unimodal distribution of latencies. This deficit persisted throughout testing, which in one monkey continued for 9 mo. Express saccades were not observed again for saccades contralateral to the lesion, and the mean latency of the contralateral saccades was longer than the mean latency of the second peak for the ipsiversive saccades. The latency distribution of saccades ipsiversive to the collicular lesion was unaffected except for a few days after surgery, during which time an increase in the proportion of express saccades was evident. Saccades obtained with the discrimination paradigm yielded a small but reliable increase in saccadic latencies following collicular lesions, without altering the shape of the distribution. Unilateral muscimol injections into the superior colliculus produced results similar to those obtained immediately after collicular lesions: saccades contralateral to the injection site were strongly inhibited and showed increased saccadic latencies. This was accompanied by a decrease of ipsilateral saccadic latencies and an increase in the number of saccades falling into the express range. The results suggest that the superior colliculus is essential for the generation of short-latency (express) saccades and that the frontal eye fields do not play a significant role in shaping the distribution of saccadic latencies in the paradigms used in this study.(ABSTRACT TRUNCATED AT 400 WORDS)


1987 ◽  
Vol 64 (3_suppl) ◽  
pp. 1239-1242 ◽  
Author(s):  
Darhl M. Pedersen

A Privacy Questionnaire was administered to 118 male and 142 female college students to determine differences in the patterns of privacy preferences between the sexes. The questionnaire contained factor scales for measuring six independent types of privacy. t-tests showed that the means for women were significantly higher than those for men in their preferences for Intimacy with Family and Intimacy with Friends. On the other hand, for Isolation the mean for men was significantly higher than that for women. There were no significant differences between the means for the two sexes on the remaining three dimensions, Reserve, Solitude, and Anonymity.


1910 ◽  
Vol 30 ◽  
pp. 555-561 ◽  
Author(s):  
R. A. Houstoun

Practical men are accustomed to measure the efficiency of a glow-lamp in watts per candle or, in other words, by the quantity of energy which must be supplied to it for every mean spherical candle-power of light it gives. The energy supplied is measured by an ammeter and voltmeter, and the mean spherical candle-power is obtained on the photometric bench by comparing the light given in different directions with that of some standard source. The watts per candle together with the life and initial cost of the lamp determine its commercial value.On the other hand, we may regard the lamp as an energy-transforming device, and measure its efficiency by the percentage of electrical energy it transforms into light.


2013 ◽  
Vol 44 (3-4) ◽  
pp. 349-372 ◽  
Author(s):  
Zoltán Varga ◽  
László Ronkay

The basic architecture of the external genitalia of Noctuidae (“genital capsula”) is bilaterally symmetric. Secondary asymmetry is well-known in different subfamilies and tribes. We review and interpret the functions and processes which may be responsible for secondary asymmetry (i.e., dissymmetry) of these structures in terms of structural vs. behavioural working hypotheses. We consider the genital structures as correlated elements of a complex structure (“bauplan”) in which some changes in details can be explained by selection due to optimization of the reproductive success. Major pathways of changes are, however, delimited by some structural constraints which appear in parallel in different phyletic lines of trifine Noctuidae. One of these constraints is the subsistence of symmetry in structures with own musculature. On the other hand, some rigid parts without own musculature can evolve more rapidly and divergently in connection with the different allocation of functions. Such asymmetric structures may have some selective advantages due to the more effective stimulation, on one side, and fixation of genital parts during copulation, on the other. Asymmetric structures can effectively enhance the variations of the spatial geometry but without change of the “bauplan” which can be preserved in parallel in different taxonomical groups. It means that the originally symmetric “bauplan” with its homologies can be considered as a phyletic “heritage”, while the functional dissymmetrisation driven by selective optimization is the “habitus” in which numerous homoplasies can occur.


1940 ◽  
Vol 36 (3) ◽  
pp. 314-322 ◽  
Author(s):  
R. d'E. Atkinson

The derivation given by Hoyle and Lyttleton for an accretion formula proposed by them is examined. A number of arguments against its validity are put forward, especially that on the one hand their capture radius depends on the theorem that if the velocity of certain masses of gas after collision is less than the velocity of escape at the point, they will not in fact escape, while on the other hand it is clear (and is now admitted) that the gas cannot in fact move with this velocity at all. It is also shown that since, ex hypothesi, the individual molecules will all, on the average, retain their hyperbolic velocities, there is not the compelling reason for their capture that there appeared to be in Hoyle and Lyttleton's argument, where only the mean radial velocity of the centre of gravity of the mass was considered. Further, it seems improbable that the temperature of the interstellar matter can be low enough for the initial assumptions of their theory to hold.


Geophysics ◽  
1979 ◽  
Vol 44 (8) ◽  
pp. 1464-1464
Author(s):  
J. R. Hearst ◽  
R. C. Carlson

Our equations (3) and (4) are correct. They represent the difference between the attraction of the shell viewed from [Formula: see text], the outer radius of the shell, and [Formula: see text], its inner radius. (The attraction of the shell viewed from [Formula: see text] is zero.) On the other hand, equations (5) and (6) of Fahlquist and Carlson represent the difference in attraction of the entire earth from the same viewpoints and thus, as they say, include a free‐air gradient term. However, their equation (5) would be correct only if the mean density of the earth were equal to that of the shell, and the free‐air gradient obtained by their equation (10) is correct only under these circumstances.


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