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J M Baribeau

Publications and source records attributed to J M Baribeau.

5 recordsLinked to original sources
PubMed1995

A transmission electron microscope (TEM) calibration standard sample for all magnification, camera constant, and image/diffraction pattern rotation calibrations.

A calibration sample for transmission electron microscopy (TEM) has been developed that performs the three major instrument calibrations for a transmission electron microscope: the image magnification calibration for measurements of images, the camera constant calibration for indexing diffraction patterns, and the image/diffraction pattern rotation calibration for relating crystal directions to features in the image. This offers an improvement over commercially available calibration standards, where up to five different samples are required to perform these three calibrations. The new calibration sample consists of an electron-transparent cross-sectional TEM sample made from a molecular beam epitaxy (MBE)-grown, single-crystal semiconductor wafer. When the calibration structure is viewed in a TEM, it appears as a series of light and dark layers where the layer thicknesses are very accurately known. The calibrated thickness measurements of these light (silicon) and dark (SiGe alloy) layers are based on careful TEM measurements of the [111] lattice spacing of silicon which is visible on the calibration sample itself, and are supported by X-ray diffraction measurements. Furthermore, the layer thickness variation across the entire silicon wafer has been verified to be less than 1%, allowing all samples prepared from the same wafer to have errors in the given layer thickness values of less than 1%. As the sample is a single crystal of silicon, the calibrations requiring electron diffraction information such as the camera constant calibration and the image/diffraction pattern rotation calibration can also be performed easily and unambiguously. One single calibration sample can therefore be used to provide all three of the major TEM instrument calibrations at all magnifications and all camera lengths.

Calibration↗
PubMed1988

Emotional facial expressive and discriminative performance and lateralization in normal young adults.

Studies of cerebral dominance for posed emotional facial expression using free-viewing of hemicomposites have produced inconclusive findings, and the concordance of facial emotion identification (discrimination) and the expression of the same facial emotion remains unknown. Expressive and discriminative (14 men, 14 women) facial emotion performances of undergraduates and the lateralization of full-face and lower-face hemicomposite photographic montages of the expressions of six transcultural emotions (joy, sadness, fear, surprise, disgust, anger) as ascertained by 15 male and 15 female undergraduate judges were analyzed. All groups were matched for age and education. The lower face was non-significantly left-face dominant, sadness was strongly significantly right-face dominant and fear was non-significantly left face dominant. Both sexes were equally lateralized overall and demonstrated the same pattern as described above, though slight (apparently trivial) differences appeared in multivariate analysis, and in univariate interactions. Results were interpreted as non-supportive of a simple right hemisphere dominance model of facial affect, nor of a left-hemisphere-negative/right-hemisphere-positive model. It was concluded that facial affect dominance results are coherent only within, and not between, methods such as free viewing hemicomposite and tachistoscopic methods, and tasks, such as expressive and discriminative tasks.

Adult↗
PubMedDate not supplied

Does severe traumatic closed head injury impair sense of humour?

It is now known that closed head injury (CHI) impairs interpersonal skills, disturbs and/or blunts mood and compromises emotional discriminativeness. This study tried to test whether sense of humour is also impaired or disturbed following CHI. Subjects were 42 CHI patients and 42 normal controls, matched for age, education and paternal occupation. Humour performance measures included time taken to rank jokes according to funniness and to classify them, stability of funniness rankings at re-test and ability to correctly classify jokes into 'mutilated' and 'intact' categories. Non-performance measures included total number of non-verbal vocalizations, and mean percentage of appreciation of the jokes. The CHI patients were highly significantly impaired on all aspects of performance but did not differ from the normals on non-performance measures. However, when vocabulary (WAIS-R) was co-varied out of the analyses only time to rank funniness remained significant. The results were interpreted to suggest a severe impairment of sense of humour, an important cause of which is a narrow lexicon, poor lexical semantic processing, or some other reading dysfunction, some of which probably antedated the CHI. It was concluded that measures of humour, vocabulary, and of pure affective performance such as prosodic and/or facial emotion discrimination could contribute to the rehabilitation process in severe CHI.

Adolescent↗
PubMedDate not supplied

Processing of pragmatic and facial affective information by patients with closed-head injuries.

Although several affective impairments have been demonstrated to occur following closed-head injury (CHI), deficits of the communicative function of language, particularly sentenial and suprasentential pragmatic aspects, have been suggested, but not demonstrated, to occur. This study compared 31 normals and 31 severely closed-head injured patients matched for age, sex and education. The dependent measures consisted of a facial test of emotion (FTE) and a contextual test of emotion (CTE). The former task consisted of 36 slides representing facial expressions of the six emotions demonstrated by Ekman and colleagues to be transcultural, namely, job, sadness, fear, anger, surprise and disgust. The subject was required to name the appropriate emotion for each slide. The latter task consisted of correctly identifying the appropriate emotion for each of 36 brief verbal narratives representing contexts connotative of the same six transcultural emotions. The CHI patients were impaired overall on the FTE but not the CTE. However, the ability to identify anger was significantly impaired on both tasks when considered in isolation from the other emotions. It was concluded that a processing deficit of primary emotional material, particularly anger, does exist following CHI, but that this deficit is not necessarily independent of task and/or modality parameters. It was also concluded that evidence of a pragmatic deficit of the language function following CHI remains to be provided at this time.

Adult↗