2,160 research outputs found
Anatomical validation of middle cerebral artery position as identified by transcranial pulsed Doppler ultrasound
No full textThe basal cerebral arteries were insonated using transcranial pulsed Doppler ultrasound (TPDU) at 2 MHz. The Doppler sample volume (SV) depths at which signals were obtained which could be attributed to the middle, anterior and posterior cerebral arteries (MCA, ACA and PCA) were compared with measurements in adult cadavers and with B-scan ultrasound studies in infants. The depth of the internal carotid artery (ICA) terminal division into ACA and MCA was closely correlated for both groups. In adults, it was found at 5-6 ± 10 cm using TPDU while in cadavers it was found at 5 3 ± 05 cm from the temporal bone. In infants, it was found at 3-2 ± 03 cm for the right side, and 3-2 ± 0-2 cm for the left side using TPDU, and at 3-4 ± 04 cm and 3-4 ± O 5 cm for right and left sides respectively using B-scan ultrasound. The mean depth of the MCA mid-point in infants as defined by TPDU and B-scan was also closely correlated, with values of 2-8 ± 03 cm and 2-7 ± 03 cm for right and left sides respectively using TPDU and of 2-8 ± 04 cm and 2-7 ± 04 cm for right and left sides respectively using B-scan ultrasound. Values for the most lateral part of the MCA did not correlate. In adults, signals from the ACA and PCA were obtained at greater SV depth than the MCA, thus preventing confusion.</p
Portrait of author Jackson A. Graves, [s.d.]
No full textPhotographic portrait of author Jackson A. Graves, [s.d.]. Graves is shown from his upper torso to his head and is looking to the right. He is wearing a light-colored suit, a light shirt, and a dark tie with a square pattern. He has light-colored hair that is neatly combed and parted at left, a thick light mustache, and light eyebrows. There are large bags beneath his eyes and his ears are very big
Simulation and Control of a Pneumatic Muscle Actuator for a Rehabilitation Robot
No full textThe perfomance of a pneumatic muscle actuator, invented by Jim Hennequin and used in a prototype wheelchair-mounted robot ann designed by the first author is reported. Experimental measurements were made of the output torque versus rotary motion and internal pressure. The torque available for a muscle of size 60 mm width by 90 mm length ranges from 1 to 15 Nm. The rotary stiffness of this muscle is 0.081 Nm/deg. A simulation model of the dynamic behaviour of the muscle attached to the robot arm using one-dimensional flow theory was written in ACSL (Advanced Continuous Simulation Language). The resultant simulation gives good agreement to within ± 5% of the experimental values. Control using proportional and a PID controller is shown to be effective
Painted portrait of Father Geronimo Boscana, O.F.M., author of Chinigchinich, [s.d.]
No full textPhotograph of a painted portrait of Father Geronimo Boscana, O.F.M., author of "Chinigchinich", [s.d.]. The friar is at center, is shown from his upper torso to his head and is looking slightly to the right. He is wearing a light-colored hooded robe with the hood pulled halfway up his head. He has some thin white hair but is mostly bald. Chinigchinich was an account of California Indian life, focused on the Indians near San Juan Capistrano
Portrait of James Laughlin, author of "This Is My Blood," [s.d.]
No full textPhotographic portrait of James Laughlin, author of "This Is My Blood," [s.d.]. A elderly man with smiling eyes turns his face toward the camera. He has a slight smile on his face, and a large nose, bushy eyebrows and slicked-back graying hair. He wears a light-colored suit, striped tie, and undergarment.; The book was to be published March 3, 1989 in a limited edition by The Yolla Bolly Press
Fields of activity significance scientific college students [Campos de significación de la actividad científica en estudiantes universitarios]
No full textThis study has as purpose to show the beliefs, attitudes, knowledge and stereotypes of university students about scientific research. In order to reach it, the author carried out an exercise based on associative questions, individual and group interviews and a multiple choice questionnaire that was proposed to 273 students enrolled at two university centers at Guadalajara University (Universidad de Guadalajara). The information was then analyzed by means of the mixed content technique (open answers) and the statistic program SPSS (multiple choice questionnaire). The results show that most of the interview students have erroneous conceptions about the scientific duty and a very imprecise picture about the scientist and the domain and space in which he/she works. Since those social representations have been built throughout the student's academic life by several media (formal and informal), the author considers that it is essential to analyze them in order to increase the interest about scientific activity amongst the students
Fields of activity significance scientific college students [Campos de significación de la actividad científica en estudiantes universitarios]
No full textThis study has as purpose to show the beliefs, attitudes, knowledge and stereotypes of university students about scientific research. In order to reach it, the author carried out an exercise based on associative questions, individual and group interviews and a multiple choice questionnaire that was proposed to 273 students enrolled at two university centers at Guadalajara University (Universidad de Guadalajara). The information was then analyzed by means of the mixed content technique (open answers) and the statistic program SPSS (multiple choice questionnaire). The results show that most of the interview students have erroneous conceptions about the scientific duty and a very imprecise picture about the scientist and the domain and space in which he/she works. Since those social representations have been built throughout the student's academic life by several media (formal and informal), the author considers that it is essential to analyze them in order to increase the interest about scientific activity amongst the students
Transcranial pulsed Doppler ultrasound findings in brain stem death
No full textData are presented from transcranial insonation of the middle cerebral artery (MCA) performed at intervals in 23 unconscious children for whom the outcome was subsequently poor. Once an MCA signal had been observed over a 30 minute period with time averaged velocity less than 10 cm s1 and/or a direction of flow index, DFI, defined as 1 minus the ratio of reverse to forward flow of less than 08, recovery to forward flow throughout diastole was never observed and no patient recovered brain stem reflexes. Recovery of forward flow in diastole, and of brain stem function, was seen in cases with time averaged MCA velocity in the range 10 to 25 cm s1 and with reverse flow but a DFI of greater than 0-8 for short periods of time. All but one of the 13 children fulfilling clinical criteria for brain stem death had MCA signals with time averaged velocity of less than 10cm/s and DFI of less than 0-8. This type of signal was not observed in five children who were left in a persistent vegetative state.</p
View of an open-air produce market in the Central Manufacturing District, [s.d.]
No full textPhotograph of a view of an open-air produce market in the Central Manufacturing District, [s.d.]. A wide paved area can be seen at center and is crowded with merchants, trucks, and stacks of produce. Long two-story warehouses can be seen on either side of the selling area. Cloth awnings line the first floor of the warehouses at right. Lamps can be seen hung from wires strung between the buildings, as well as on light posts at left.; Legible signs include, from left: "A. Levin Co.", "Hall, Haas & Vessen", "Commission Merchants", "Distributors Beaumont Cherries and Peaches", and "Star Produce Co."
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