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At least 361 records · Page 20Linked to original sources
PubMed2007

Double plasma mirror for ultrahigh temporal contrast ultraintense laser pulses.

We present and characterize a very efficient optical device that employs the plasma mirror technique to increase the contrast of high-power laser systems. Contrast improvements higher than 10(4) with 50% transmission are shown to be routinely achieved on a typical 10 TW laser system when the pulse is reflected on two consecutive plasma mirrors. Used at the end of the laser system, this double plasma mirror preserves the spatial profile of the initial beam, is unaffected by shot-to-shot fluctuations, and is suitable for most high peak power laser systems. We use the generation of high-order harmonics as an effective test for the contrast improvement produced by the double plasma mirrors.

Journal Article↗
PubMed2000

The immediate effects of glare and electrochromic glare-reducing mirrors in simulated truck driving.

In this experiment 12 experienced truck drivers drove a fixed-base driving simulator for three 8-h sessions under simulated nighttime driving conditions. Sessions included (a) no glare, (b) intermittent glare presented in the exterior rearview mirrors to simulate following vehicles, and (c) intermittent glare with electrochromic glare reduction. The driving task combined vehicle control on straight and curved road segments with detection of pedestrians appearing alongside the road and targets appearing in the rearview mirrors. The presence of glare slowed detection of pedestrians and, to a lesser extent, slowed the detection of targets appearing in mirrors. Glare was also associated with increased lane position variability, reduced speed on curves, and, most consistently, increased steering variability. We found only meager evidence that electrochromic glare reduction improved target detection performance and no evidence that glare reduction improved vehicle control, despite the fact that participants consistently voiced positive preferences for glare reduction. The results will aid decision making that requires incorporation of the benefits of electrochromic glare-reducing mirrors.

Adult↗
PubMed2004

Enhanced accuracy in novel mirror drawing after repetitive transcranial magnetic stimulation-induced proprioceptive deafferentation.

When performing visually guided actions under conditions of perturbed visual feedback, e.g., in a mirror or a video camera, there is a spatial conflict between visual and proprioceptive information. Recent studies have shown that subjects without proprioception avoid this conflict and show a performance benefit. In this study, we tested whether deafferentation induced by repetitive transcranial magnetic stimulation (rTMS) can improve mirror tracing skills in normal subjects. Hand trajectory error during novel mirror drawing was compared across two groups of subjects that received either 1 Hz rTMS over the somatosensory cortex contralateral to the hand or sham stimulation. Mirror tracing was more accurate after rTMS than after sham stimulation. Using a position-matching task, we confirmed that rTMS reduced proprioceptive acuity and that this reduction was largest when the coil was placed at an anterior parietal site. It is thus possible, with rTMS, to enhance motor performance in tasks involving a visuoproprioceptive conflict, presumably by reducing the excitability of somatosensory cortical areas that contribute to the sense of hand position.

Adolescent↗
PubMed1979

Comparison of observational recordings in vivo, via mirror, and via television.

Simultaneous observational recordings were made in vivo, via an observation mirror, and via closed circuit television. Three of nine observers had extensive experience recording behavior in vivo; three had extensive experience recording behavior via mirror; and three had extensive experience recording via television. Observers recorded nine categories of disruptive behavior for children in a special class setting. Frequencies of behavior recorded in vivo, via mirror, and via television differed significantly for only one category, vocalization. There were no significant main effects or interactions involving the observers' previous experience. Occurrence reliability coefficients computed within and between media demonstrated the similarity of observer agreement in all three media. Data collection procedures using an observational mirror or closed circuit television appear to be reasonable alternatives to in vivo observation in circumstances similar to those in the present study.

Journal Article↗
PubMed2004

Meningocele with cervical dermoid sinus tract presenting with congenital mirror movement and recurrent meningitis.

Dermoid sinuses and meningoceles are seldom encountered in the cervical region. Besides, to the best of our knowledge, the coexistence of these types of congenital abnormalities with recurrent meningitis, as well as with mirror movement, has never been reported before. A 14-year-old female with the diagnosis of recurrent meningitis was referred to our clinic from the Department of Infectious Diseases. She had a cervical meningocele mass that was leaking cerebro-spinal fluid (CSF) and an associated mirror movement symptom. Spina bifida, dermoid sinus and meningocele lesions were demonstrated at the C2 level on computed tomography (CT) and magnetic resonance imaging (MRI). She underwent an operation to remove the sinus tract together with the sac, and at the same time the tethered cord between the sac base and the distal end of the spinal cord was detached. The diagnosis of dermoid sinus and meningocele was confirmed histopathologically. These kinds of congenital pathologies in the cervical region may also predispose the patient to other diseases or symptoms. Herein, a case of meningocele associated with cervical dermoid sinus tract which presented with recurrent meningitis and a rare manifestation of mirror movement is discussed. Neurosurgeons should consider the possible coexistence of mirror movement and recurrent meningitis in the treatment of these types of congenital abnormalities.

Adolescent↗
PubMed2003

The mirror effect and the spacing effect.

In the mirror effect, there are fewer false negatives (misses) and false positives (false alarms) for rare (low-frequency) words than for common (high-frequency) words. In the spacing effect, recognition accuracy is positively related to the interval (spacing or lag) between two presentations of an item. These effects are related in that they are both manifestations of a leapfrog effect (a weaker item jumps over a stronger item). They seem to be puzzles for traditional strength theory and at least some current global-matching models. A computational strength-based model (EICL) is proposed that incorporates excitation, inhibition, and a closed-loop learning algorithm. The model consists of three nonlinear coupled stochastic difference equations, one each for excitation (x), inhibition (y), and context (z). Strength is the algebraic sum (i.e., s = x - y + z). These equations are used to form a toy lexicon that serves as a basis for the experimental manipulations. The model can simulate the mirror effect forced-choice inequalities and the spacing effect for single-item recognition, all parameters are random variables, and the same parameter values are used for both the mirror and the spacing effects. No parameter values varied with the independent variables (word frequency for the mirror effect, lag for the spacing effect), so the model, not the parameters, is doing the work.

Cues↗
PubMed2000

Mirror reversal simply explained without recourse to psychological processes.

This paper proposes a simple and definitive solution to the mirror reversal problem, "Why does a mirror reverse left and right but not up and down?" The solution is given by combining the inversion caused by the optical process of mirroring and the definition of the left-right axis. Thus the left-right reversal of mirror images essentially does not involve psychological processes, in contrast to the multiprocess hypothesis recently proposed by Takano.

Humans↗
PubMed1998

Mirror image artifacts of color Doppler images causing misinterpretation in carotid artery stenoses.

A knowledge of mirror image artifacts in color-coded duplex sonography is important as they can lead to diagnostic problems in the morphologic evaluation of stenoses and plaques. Mirror image artifacts were detectable in stenosed vessels when strongly reflecting plaques on the wall of the vessel distant from the transducer head were insonated obliquely. The artifacts were revealed in regions that were hypoechoic or anechoic on B-mode scans. Depending on the angle of insonation and the surface structure of the plaque, the mirror image artifact could be linked with the vessel lumen and thus imitate ulcerations or branches. The artifact appeared in both the longitudinal and the transverse projections and also occurred in the power Doppler and in pulsed Doppler sonographic modes. Mirror image artifacts with linkages to the vessel lumen that could result in a misinterpretation were seen in 2.5% of the stenosed vessels.

Arteriosclerosis↗
PubMed2001

[A case report of mirror writing with low perfusion of bilateral anterior cerebral arteries].

A 20-year-old female experienced temporary unintentional mirror writing associated with low perfusion of the bilateral anterior cerebral arteries. When she was 17 years old, she had developed multiple idiopathic intracerebral hemorrhages and right hemiparesis. At the age of 20, she had a generalized convulsion for which she was transferred to our department. Computed tomography (CT) and magnetic resonance images of the brain were obtained, but no fresh abnormal lesion could be detected. The following day, after she had recovered from postictal symptoms, she wrote mirror image words, and her mirror writing then gradually improved within one week. Single photon emission CT showed low perfusion of both anterior cerebral arteries. We concluded that bilateral vascular insufficiency to the supplementary motor areas and corpus callosum caused mirror writing in this case.

Adult↗
PubMed2001

[The relevance of mirror examination in modern otorhinolaryngology].

INTRODUCTION: The aim of this study was to investigate whether the teaching of mirror examination of the larynx and rhinopharynx is still relevant and to estimate whether it is still a reliable examination. MATERIAL AND METHOD: Twenty-five patients underwent a mirror examination of the larynx and rhinopharynx by a young doctor, a young otorhinolaryngologist, and a senior otorhinolaryngologist. RESULTS: Not surprisingly the senior otorhinolaryngologist conducted the most adequate examinations. Forty-three percent of the laryngoscopies were adequate, that is all anatomic structures were seen. Forty-one per cent provided a reasonable survey, that is a few anatomic structures were not seen. This shows that 84% of the laryngoscopies could be used to give a reasonable examination of the larynx. Only 27% of the rhinoscopies were completely adequate, and as many as 49% were inadequate. DISCUSSION: Routine mirror examination of the larynx adequately provides a reliable diagnosis in most patients. But in some, it is not adequate, and here fibrolaryngoscopy is a good alternative and a more reliable examination. Mirror examination of the rhinopharynx is difficult, so if a disease of the rhinopharynx is suspected, the patient must be given a fibroscopy and biopsy under general anaesthesia.

Adult↗
PubMed2001

Tracking responses related to self-recognition: a frequency comparison of responses to mirrors, photographs, and videotapes by cotton top tamanins (Saguinus oedipus).

The frequency of responses cotton top tamarins (Saguinus oedipus) emitted indicative of self-recognition to a mirror was compared with the frequencies of responses emitted to digitized photographs of tamarins (Experiment 1) and to videotapes of real-time or prior tamarin action (Experiment 2). Results indicated more attentional responses toward the mirror in both studies, but behavioral indices of self-recognition were not consistently generated by the mirror. The 2 experiments confirmed that real-time self-reflection is a condition that generates heightened attention and rare examples of particular mirror-specific behaviors in tamarins.

Animals↗
PubMed1992

Visuo-spatial discrimination and mirror image letter reversals in reading.

This review compares visuo-spatial and linguistic mechanisms for discriminating between mirror image letters. The conclusion is drawn that both processes play a role in efficient reading, their relative contributions varying with reading experience and ability. It is shown that arguments used to reject visuo-spatial theories in mirror image letter reversals are flawed. Attention is drawn to the importance of visuo-spatial discrimination of mirror image letters, based on confident left/right body awareness, for beginning readers and for older children who are deficient in compensatory linguistic skills. When confused left/right body awareness is found in association with reversal problems, there is an indication to provide remediation that includes the promotion of mirror image letter discrimination based on confident left/right body awareness. Early intervention (pre-school and infants class) programs that teach left/right body awareness as a pre-reading skill are justified when the progress of beginning readers is facilitated and the need for remedial intervention is reduced in later years.

Child↗
PubMed2004

[An anastomosis assist mirror; a new device for off-pump coronary artery bypass].

An anastomosis assist mirror for off-pump coronary artery bypass (OPCAB) is described. This new device is designed to make a view of the circumflex coronary artery which is often troublesome to access during OPCAB. It is composed of 3 parts: a small circular mirror, a paper clip and a flexible arm between the mirror and the clip. The paper clip is situated at an edge of a sternal retractor. The mirror is positioned beside the sheer surface of the lateral wall of the heart by regulating the flexible arm. It shows a flat, reflective view of the anastomotic site and makes an anastomosis easy. The device enables us to avoid excessive manipulation on the heart and hemodynamic instability, thereby reducing unnecessary volume overload, inotropic drugs or mechanical cardiac assistance.

Anastomosis, Surgical↗
PubMed2004

Electron immunocytochemical demonstration of serotonin, vasoactive intestinal polypeptide, bombesin, somatostatin and glucagon in mirror biopsies from primary colorectal adenocarcinoma.

The aim of this study was to investigate the ultrastructural appearance of mirror biopsies from primary colorectal adenocarcinomas combined with serotonin, vasoactive intestinal polypeptide, bombesin, somatostatin and glucagon expression in order to clarify the histology and immunology of these tissues compared with colorectal adenocarcinomas. The investigation was carried out in 90 cases of mirror biopsies by electron microscope immunocytochemistry. The ultrastructural study revealed that some cases (30%) of mirror biopsies were characterized by the presence of intracellular changes compared to normal tissues. The most significant of them were the presence of swollen abnormal mitochondria and the increased number of the secretory cells. The above enzymic and secretory changes were confirmed by electron immunogold results. Bombesin and VIP appeared to be located in enterochromaffin-like (ECL) endocrine cells primarily responsible for the production of serotonin. Somatostatin was located in D cells while we found numerous glucagon (EG) immunoreactive cells. In conclusion, low somatostatin expression, high glucagon and serotonin expression and the ectopic secretion of VIP and bombesin neuropeptides in mirror biopsies indicate the preneoplastic nature of these tissues and may be useful for the optimal treatment of patients with colorectal adenocarcinoma.

Adenocarcinoma↗
PubMed2006

[Mirror phenomena in patients with different autoimmune disorders].

The aim of the article was to study functional asymmetry between hemispheres and to find an ability to mirror phenomena in 25 patients with systemic lupus erythematosus (SLE) and 12 patients with multiple sclerosis. Patients with SLE had the following individual profiles of functional asymmetry: right, mainly right, mixed and mainly left. Nobody of them had either symmetric or left profiles. An ability to mirror phenomena (mirror drawing and mirror writing) has been found in 56% of SLE patients with different individual profiles of functional asymmetry. These patients significantly differed from the control group and patients with multiple sclerosis.

Adult↗
PubMed1991

Hand-mirror variant of microgranular acute promyelocytic leukemia.

We report a case of microgranular acute promyelocytic leukemia (APL, M3 V) presenting with the typical features of disseminated intravascular coagulopathy and cells with irregular, folded, or bilobed nuclei with occasional intracytoplasmic multiple Auer rods in the peripheral blood. A cytogenetic study of the bone marrow and blood showed translocation between chromosomes 15 and 17, characteristic of APL. The flow cytometric study also confirmed this diagnosis. The unusual feature in this case is the existence of 80% hand-mirror cells, which also contain multiple Auer rods, in the bone marrow. The hand-mirror variant of acute leukemia has been frequently encountered in acute lymphoblastic leukemia, but documented in only six cases of acute myelogenous leukemia, including the FAB groups of M1, M2, M4, and M5. This patient is, to our knowledge, the first reported case of a hand-mirror variant in microgranular APL. The mechanism of hand-mirror cell formation and its prognostic implication are discussed.

Bone Marrow↗
PubMed1987

Behavior of young children with Down syndrome before the mirror: finding things reflected.

Children with Down syndrome (DS) and normally developing (ND) children of comparable mental age (16-32 months) were compared in their ability to find things seen in the mirror. Tasks included finding a rouge mark on the face, finding the mother, finding a toy, as well as free play before the mirror. The 2 groups were found to be equally likely to solve each task and did not differ in pattern of tasks solved or amount of prompting to notice the stimulus. With increasing mental age, both groups required less prompting and were more likely to locate the stimulus. Children with and without DS were not equally interested in particular tasks, and children with DS were more attentive to the mirror overall, whereas ND children tended to lose interest more rapidly in some task situations. The significance of incorrect strategies in searching for the reflected mother or toy was also examined. It was concluded that the ability of children with DS to solve different kinds of mirror tasks paralleled that of ND children, but that motivational, attentional, and exploratory differences may exist.

Attention↗
PubMed1980

Acute lymphoblastic leukemia: hand mirror variant.

The presence of numerous hand mirror cells in the bone marrow of patients with acute leukemia may be related to a good prognosis. To further evaluate this relationship, the bone marrows of 21 consecutive patients with a diagnosis of acute lymphoblastic leukemia were reviewed for the presence of greater than 40% hand mirror cells. Four of these 21 patients (19%) demonstrated this finding during the course of their illness. These patients were characterized by ease of remission and/or prolonged survival. Three (75%) patients are alive and well at the time of this writing. At the present time, of the 17 patients without hand mirror cells, seven (41%) are alive and ten (59%) are dead. Although not statistically significant, our findings suggest a positive relationship between the presence of greater than 40% hand mirror cells in the bone marrow ans a favorable prognosis. Future larger prospective studies are indicated to further understand the importance of this complex, apparently immunologically stimulated cell.

Adult↗