176,993 research outputs found
Influence of aging on leg muscle reflex responses to stance perturbation
No full textThe effect of age on latency and amplitude of leg muscle responses to stance
perturbations was studied in 75 control subjects. They stood upright on a
platform and were displaced by toe-up (upward tilt) and toe-down (downward tilt)
platform rotations. Perturbations were induced during free and supported stance
(holding on to a stable structure). Surface electromyograms (EMG) of the soleus
(Sol) and tibialis anterior (TA) were recorded and latency and area of responses
were measured. Body sway variables during stance with open or closed eyes were
also recorded. Upward tilt evoked a short-latency response (SLR) in Sol and a
long-latency response (LLR) in TA. Downward tilt evoked a medium-latency response
(MLR) in TA and a LLR in Sol. This pattern of EMG responses was similar in both
young and elderly subjects, although there were some differences in latency and
amplitude. There was a significant relationship between latency of all responses
and age. Slope of the regression lines of TA LLR, TA MLR, and Sol LLR was steeper
than that of Sol SLR. Area of Sol SLR was unrelated to age, but a positive trend
was identified in the other responses, significant for TA LLR. Under
supported-stance condition, amplitude of TA MLR, TA LLR, and Sol LLR was
decreased to a similar extent in both young and elderly subjects. There was a
weak relationship between age and most body sway variables. A significant
relationship was found between most sway variables and latency of Sol SLR and
LLR, chiefly with eyes closed. Neither TA MLR nor LLR were significantly
correlated with sway variables, but a trend was present for TA MLR with eyes
closed
Early and late stretch responses of human foot muscles induced by perturbation of stance
No full textIn eight subjects standing on a movable platform, surface EMG activity was
recorded from the foot muscles extensor digitorum brevis (EDB) and flexor
digitorum brevis (FDB) and from the leg muscles soleus (Sol) and tibialis
anterior (TA) during perturbations of upright stance. Perturbations inducing foot
dorsiflexion (upward tilt and backward translation) evoked a short-latency
response (SLR) and a medium-latency response (MLR) to stretch in the
physiological extensors FDB and Sol, and a long-latency response (LLR) in the
physiological flexors EDB and TA. Perturbations inducing plantar-flexion
(downward tilt and forward translation) evoked the MLR in EDB and TA, and the LLR
in FDB and Sol. The latency of the FDB and Sol SLR was compared to that of the H
and T reflexes evoked in the same muscles by electrical or mechanical
stimulation, respectively. In both muscles, the T reflex and the SLR followed the
H reflex at delays accounted for by the different stimulation mode, indicating
that the SLR induced in both muscles by upward tilt and backward translation was
a true autogenetic stretch reflex from spindle primaries. The time interval
between the onset of SLR and of MLR was significantly greater for the FDB than
the Sol muscle, suggesting that MLR is a spinal reflex travelling through slower
peripheral afferent pathways than SLR. From these latency differences and from
the distance between the muscles, we calculated in four subjects the conduction
velocity of the afferent fibres presumably responsible for the MLR in FDB. This
was about 29 m/s. LLRs were evoked in TA and EDB during upward tilt and backward
translation, and in Sol and FDB during downward tilt, but not forward
translation. LLRs did not adhere to a proximal-to-distal pattern, since these
could appear earlier in the foot than in the leg muscles. All responses were
modulated by perturbation type (tilt vs translation) and body posture (normal
stance vs forward leaning). Both the large amplitude of the foot muscle responses
and their temporal pattern indicate that the muscles acting on the toes play a
major role in stabilising posture. Their action increases in amplitude and
extends in time the foot-ground reaction force, thereby improving the efficiency
of the superimposed action of the leg muscle responses
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Letter from R. R. Zellick, Assistant Trust Officer, Anglo California National Bank of San Francisco, to Joseph R. Goodman, October 2, 1942
No full textLetter from R. R. Zellick, Assistant Trust Officer at The Anglo California National Bank of San Francisco, to Joseph R. Goodman, regarding property owned by Dave Tatsuno. Zellick mentions a dispute between current tenants and Tatsuno, and that Tatsuno has asked Goodman to help locate trustworthy tenants.Personal correspondence, organizational records, government documents, publications, and other papers created or collected by Joseph R. Goodman documenting the forced removal and incarceration of Japanese Americans during World War II, as well as organized resistance to incarceration. Included in the collection are records of the Japanese Young Men's Christian Association and the Japanese American Citizens' League in San Francisco, including papers of the Japanese YMCA's executive secretary Lincoln Kanai; Sakai family papers; Goodman's correspondence to and from Japanese American incarcerees, organizations opposing forced removal and incarceration of Japanese Americans, the War Relocation Authority, and others; publications, photographs, and ephemera from the Topaz Relocation Center, where Goodman taught high school; War Relocation Authority records and publications; and newspaper clippings, pamphlets, and reports about forced removal and incarceration created by various government, religious, and civic organizations, in California and nationwide
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Liftings for noncomplete probability spaces
No full textThe current state of knowledge concerning liftings for noncomplete probability spaces is discussed. This is a somewhat expanded version of the author's talk given at the 1991 Summer Conference on General Topology and Applications in Honor of Mary Ellen Rudin and Her Work.PT: S; CR: BURKE MR, IN PRESS P AM MATH S BURKE MR, 1991, ISRAEL J MATH, V73, P33 BURKE MR, 1992, ISRAEL J MATH, V79, P289 CARLSON T, THEOREM LIFTING CHRISTENSEN JPR, 1974, TOPOLOGY BOREL STRUC FREMLIN DH, 1989, HDB BOOLEAN ALGEBRAS, P877 INOESCUTULCEA A, 1966, 5TH P BERK S MATH ST, V2 IONESCUTULCEA A, 1967, CONTRIBUTIONS PROB 1, P63 IONESCUTULCEA A, 1969, TOPICS THEORY LIFTIN JECH TJ, 1978, SET THEORY JOHNSON RA, 1980, P AM MATH SOC, V80, P234 JUST W, IN PRESS T AM MATH S KUPKA J, 1983, INDIANA U MATH J, V32, P717 LOSERT V, 1983, LNM, V1080, P95 MAHARAM D, 1958, P AM MATH SOC, V9, P987 SHELAH S, 1983, ISRAEL J MATH, V45, P90 TALAGRAND M, 1982, P AM MATH SOC, V84, P379 VONNEUMANN J, 1931, CRELLES J MATH, V165, P109; NR: 18; TC: 0; J9: ANN N Y ACAD SCI; PG: 4; GA: BZ86BSource type: Electronic(1
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