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171.
The open-field behavior of wild and domestic Norway rats was compared in 15-min tests administered over 5 successive days. Wild rats exhibited more ambulation, jumping, grooming, and time inactive than domestic rats and spent more time along the arena wall. Within- and between-trial changes in behavior were generally greater for wild rats. Factor analyses revealed major loadings on factors identified as “locomotor behavior” and “grooming.” Support was obtained for the hypothesis that domestication has raised the threshold for avoidance-escape behavior in response to a novel environment.  相似文献   
172.
    
Spatial context supports memory retrieval in adults. To understand the development of these effects, context effects on object recognition were tested in neurotypical children ages 3 years to adulthood (n 3–6 years = 34, n 10–16 years = 32, n college age = 22) and individuals with Down syndrome (DS) ages 10–29 years (n = 21). Participants engaged in an object recognition task; objects were presented in scenes and either remained in that same scene or were removed at test. In some groups (< 4.5 years and with DS) context effects were present even though object recognition was poor. After 4.5 years, children demonstrated memory flexibility, while later in adolescence context effects reemerged, showing nonlinearity in the development of these effects.  相似文献   
173.
Do oarsmen have asymmetries in the strength of their back and leg muscles?   总被引:1,自引:0,他引:1  
The aim of this study was to establish whether asymmetry of the strength of the leg and trunk musculature is more prominent in rowers than in controls. Nineteen oarsmen and 20 male controls matched for age, height and body mass performed a series of isokinetic and isometric strength tests on an isokinetic dynamometer. These strength tests focused on the trunk and leg muscles. Comparisons of strength were made between and within groups for right and left symmetry patterns, hamstring: quadriceps ratios, and trunk flexor and extensor ratios. The results revealed no left and right asymmetries in either the knee extensor or flexor strength parameters (including both isometric and isokinetic measures). Knee extensor strength was significantly greater in the rowing population, but knee flexor strength was similar between the two groups. No difference was seen between the groups for the hamstring: quadriceps strength ratio. In the rowing population, stroke side had no influence on leg strength. No differences were observed in the isometric strength of the trunk flexors and extensors between groups, although EMG activity was significantly higher in the rowing population. Patterns of asymmetry of muscle activity were observed between the left and right erector spinae muscles during extension, which was significantly related to rowing side (P < 0.01). These observations could be related to the high incidence of low back pain in oarsmen.  相似文献   
174.
The accelerated growth of sponsorship has brought increased attention and scrutiny to this relatively new area of marketing and communications strategy. In turn, researchers have focused on defining, understanding and measuring the various aspects of sponsorship. However, detailed research related to the ‘how’ of sponsorship implementation remains limited. A key aspect of implementation is known as activation, which refers to the investment by the sponsor above and beyond the fee required to acquire the official rights to that sponsorship. Activation is normally referred to as a ratio of the additional investment to the cost of the rights fees. Previous studies have offered recommended activation ratios ranging from 1:1 to as high as 8:1 in order to fully reap the rewards of sponsorship. This research seeks to enhance our understanding of sponsorship activation via an in-depth case study, a typical method for exploratory research of this nature. Specifically, we ask (i) what drives activation, (ii) what are the best methods of activation, and (iii) how much should be spent on activation? Findings suggest that management decisions regarding activation focus on the custom development of quality strategies versus increasing the activation ratio. Indeed, a formula based on a variety of factors is recommended since activation tactics and their appropriateness to a specific sponsorship are the cornerstones of sponsorship success. Overall, results present a four-step model including activation drivers, strategic considerations, activation spending, and sponsorship outcomes.  相似文献   
175.
The classical criteria for controllability and observability are given a tensorial formulation which is then extended into Boolean form directly related to a digraph interpretation of system structure. This is examined in detail with particular reference to group theoretic aspects, invariant properties under transformation, the term rank test and the existence of zero eigenvalues.Within this framework the structural design concepts of potential controllability and observability are presented in generalised terms.  相似文献   
176.
177.
This paper discusses the use of systems development research methods in the context of ongoing research that is formulating a specification for a metadata schema registry. The paper extrapolates from this discussion how such methods can be utilized in archival systems research and how such an approach differs from commercial systems engineering. In particular, the paper suggests that adopting a user-centred prototyping approach in a research context allows for exploration of the interplay between theory and practice, advancing the practice, while also offering new insights into theoretical concepts. It argues that these research methods are of increasing interest to the archival profession in order to conceptualise and realise the tools necessary to support recordkeeping and archival processes in digital environments.  相似文献   
178.
This paper characterizes the methodological foundations of national standardization in the Russian Federation, in particular in the library and information field. The activities of Technical Standardization Committee 191 Scientific and Technical Information, Librarianship, and Publishing are reported.  相似文献   
179.
In Experiment I, rats received one food rewarded trial per day in a runway. One group received all its trials under hunger (Group H); the second group received a random half of its trials under hunger and the other half of its trials under hunger plus thirst (Group H-HT). Group H-HT ultimately ran slower on HT trials than on H trials. In Experiment II, the effects of shifting from H to HT and vice versa were examined in a five-phase design. In general, rats run under H ran faster than rats run under HT, and shifts from H to HT produced rapid decreases in speed, while shifts from HT to H produced extremely slow increases in speed. The results of both experiments were interpreted as indicating that the reward value of food is greater under H than under HT and that the manipulation H vs. HT may be viewed as theoretically similar to manipulation of reward magnitude.  相似文献   
180.
The pilot issue of the data collection of the All-Russian Institute of Scientific and Technical Information of the Russian Academy of Sciences “Industry of Nanosystems and Nanomaterials” gives an approximate view of the state of this field of science at the beginning of 2007. The topics of articles in the pilot issue are analyzed. The directions of development of nanotechnologies are shown. The basic types of nanomaterials, the methods of their production, and their properties and applications are given.  相似文献   
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