Sports-Related Concussion in Helmeted vs. Unhelmeted Athletes: Who Fares Worse?

In the management of sports-related concussion, little is known about the effect of wearing or not wearing a helmet (i. e., helmet status) on the acute outcomes of concussed athletes. We endeavored to assess acute neurocognitive and symptom changes after SRC in helmeted vs. unhelmeted athletes. In a retrospective study, 1 025 athletes from 2 regional databases sustained a SRC. Athletes were matched by age, gender, number of prior concussions, and days to post-concussion test, yielding a final cohort of 138 athletes. For each group of 69, differences in post-concussion neurocognitive and symptom scores were compared using group mean differences as well as reliable change index (RCI) scores set at the 80% confidence interval. With gender, prior concussions, and days to post-concussion test similar in each group, using group mean change scores and RCI methodology, we found no significant differences between the helmeted and unhelmeted groups in 4 neurocognitive tests and one total symptom score. In a cohort of carefully matched athletes from 2 regional concussion centers, helmet status was unrelated to neurocognitive scores and total symptoms in athletes after suffering a SRC. These findings suggest that acute outcomes in helmeted vs. unhelmeted sports are quite similar.

Observation of strong coupling through transmission modification of a cavity-coupled photonic crystal waveguide.

We investigate strong coupling between a single quantum dot (QD) and photonic crystal cavity through transmission modification of an evanescently coupled waveguide. Strong coupling is observed through modification of both the cavity scattering spectrum and waveguide transmission. We achieve an overall Q of 5800 and an exciton-photon coupling strength of 21 GHz for this integrated cavity-waveguide structure. The transmission contrast for the bare cavity mode is measured to be 24%. These results represent important progress towards integrated cavity quantum electrodynamics using a planar photonic architecture.

Resolved sideband emission of InAs/GaAs quantum dots strained by surface acoustic waves.

The dynamic response of InAs/GaAs self-assembled quantum dots (QDs) to strain is studied experimentally by periodically modulating the QDs with a surface acoustic wave and measuring the QD fluorescence with photoluminescence and resonant spectroscopy. When the acoustic frequency is larger than the QD linewidth, we resolve phonon sidebands in the QD fluorescence spectrum. Using a resonant pump laser, we have demonstrated optical frequency conversion via the dynamically modulated QD, which is the physical mechanism underlying laser sideband cooling a nanomechanical resonator by means of an embedded QD.

Directional laser emission from a wavelength-scale chaotic microcavity.

We demonstrate directional output from a deformed disk laser of dimensions comparable to the emission wavelength. Unlike larger deformed cavity lasers, which exhibit universal output directionality determined by chaotic ray dynamics, the far-field patterns differ between lasing modes. The directional emission results from weak coupling of isotropic high-quality modes to anisotropic low-quality modes, combined with chiral symmetry breaking of clockwise and counterclockwise propagating waves. This mechanism makes it possible to control the output properties of wavelength-scale lasers.

4-quasi-phase-matched interactions in GaAs microdisk cavities.

We describe quasi-phase-matched nonlinear interactions in materials that possess 4 symmetry, such as GaAs. 4 symmetry together with curved propagation geometries produce quasi phase matching (QPM) without need of external domain inversions. To improve efficiency of nonlinear optical mixing, 4 -QPM can be combined with resonant microcavities such as whispering-gallery-mode microdisks. All interacting waves must be resonant with the cavity, which leads to stringent tuning requirements. We show tuning behavior for second-harmonic generation in a GaAs microdisk cavity and estimate that, with milliwatt-level external pumping, approximately 0.1% power-conversion efficiency can be obtained with negligible higher-order nonlinear effects.

Emigration stress and language proficiency as correlates of depression in a sample of Southeast Asian refugees.

This research evaluated a stress management, coping skills model of adjustment in the analysis of depression in a sample of Laotian refugees living in the southeastern United States. Stressful events and experiences during emigration and a lack of English proficiency were associated with depressive symptoms, while demographic variables and social support were not. English proficiency also significantly reduced the impact of acculturative stressors on depression, suggesting that language skill may act as a stress buffer in the new cultural environment.

Anosmia in Alzheimer disease.

Ten patients with probable Alzheimer Dementia underwent a brief evaluation of cranial nerve I function, with 90% showing varying degrees of anosmia. The potential usefulness of olfactory assessment in the evaluation of Alzheimer Disease is discussed.

Influence of a single quantum dot state on the characteristics of a microdisk laser.

We report a quantum dot microcavity laser with a cw sub-microW lasing threshold, where a significant reduction of the lasing threshold is observed when a single quantum dot (QD) state is aligned with a cavity mode. The quality factor exceeds 15,000 before the system lases. When no QD states are resonant, below threshold the cavity mode initially degrades with increasing pump power, after which saturation occurs and then the cavity mode recovers. We associate the initial cavity mode spoiling with QD state broadening that occurs with increasing pump power.

Cooperative recombination of a quantized high-density electron-hole plasma in semiconductor quantum wells.

We investigate photoluminescence from a high-density electron-hole plasma in semiconductor quantum wells created via intense femtosecond excitation in a strong perpendicular magnetic field, a fully quantized and tunable system. At a critical magnetic field strength and excitation fluence, we observe a clear transition in the band-edge photoluminescence from omnidirectional output to a randomly directed but highly collimated beam. In addition, changes in the linewidth, carrier density, and magnetic field scaling of the photoluminescence spectral features correlate precisely with the onset of random directionality, indicative of cooperative recombination from a high-density population of free carriers in a semiconductor environment.

Irrational beliefs of shoplifters.

Shoplifting has become a serious problem for retail merchants and for the criminal justice system. In response to a local court's request for mental health intervention in this problematic area, the Lubbock Regional MHMR Center developed the Shoplifter Offenders Program (SOP), an innovative and novel approach designed to reduce recidivism among convicted adult shoplifters. The principles of Ellis' rational-emotive therapy (RET) served as the conceptual foundation for the intensive, 8-hour psycho-educational group counseling experience (N = 94). Results from the first year of SOP operation are presented, with particular attention paid to the irrational beliefs of shoplifters.

Graded imagination and relaxation as components of experimental desensitization: a psychophysiological evaluation.

Studied the effects of aversive imagery gradation and muscular relaxation as procedural variables within desensitization by using (pre-vs. posttreatment) peripherally cued electrodermal responsivity as the dependent-variable measure of fear. There was no evidence that experimental desensitization or any of its procedural components yielded attenuated electrodermal responsivity to the peripheral fear cue. Because this result derives from a relatively well-done study, it poses a challenge to widespread notions about the vehicle of therapeutic effects from desensitization.

The relationship between the Overcontrolled-Hostility Scale and the MMPI 4--3 high-point pair.

Investigated the relationship between the MMPI 4--3 high-point pair and the Overcontrolled-Hostility (O-H) scale in three different populations. Ss were assigned to the 4--3 condition based on the following two criteria: (1) Scales 3 (HY) and 4 (PD) greater than or equal to T-score of 65; (2) Scale 4 (PD) greater than Scale 3 (HY) greater than or equal to all other clinical scales. In the prison sample (N = 200), inmates who achieved the 4--3 high-point pair were found to earn significantly higher scores on the O-H scale relative to a group of age-matched controls. These results were cross-validated successfully in a sample of psychology clinic outpatients (N = 500), where patients were matched on both age and sex. A similar relationship was found between the presence of a 4-3 high-point pair and higher scores on the O-H scale in a state hospital (N = 102) sample, although the results did not reach statistical significance because of the restricted sample size.

Single-mode spontaneous emission from a single quantum dot in a three-dimensional microcavity.

The spontaneous emission from an isolated semiconductor quantum dot state has been coupled with high efficiency to a single, polarization-degenerate cavity mode. The InAs quantum dot is epitaxially formed and embedded in a planar epitaxial microcavity, which is processed into a post of submicron diameter. The single quantum dot spontaneous emission lifetime is reduced from the noncavity value of 1.3 ns to 280 ps, resulting in a single-mode spontaneous emission coupling efficiency of 78%.

Olfactory dysfunction discriminates probable Alzheimer's dementia from major depression: a cross-validation and extension.

The present study was conducted to cross-validate and extend the hypothesis that olfactory dysfunction could discriminate between groups of patients with Alzheimer's disease and major depression. Forty patients meeting the DSM-IV criteria for either Alzheimer's disease or major depression (20 per group) underwent assessment with the Pocket Smell Test (PST), a three-item screening measure of odor identification, and the Mini-Mental State Examination (MMSE). A PST score of < or = 1 (1 or 0 correct) discriminated between the groups with a hit rate of 97.5% (sensitivity = 95%, specificity = 100%). The optimal hit rate for the MMSE (< or =24) was less effective (hit rate = 90%, sensitivity = 80%, specificity = 100%). Age, gender, and education had minimal impact on the PST for both groups. Olfactory assessment continues to add to the diagnostic utility in the differential diagnosis of Alzheimer's disease versus major depression in elderly patients.

Use of the MMPI in predicting psychotherapeutic persistence in groups of male and female outpatients.

Attempted to predict therapeutic persistence, as measured by the total number of sessions attended, with the MMPI. High persisters were defined as patients who attended six or more sessions, while low persisters were patients who attended fewer than six sessions. Ss were 360 (180 high persisting, 180 low persisting) female outpatients and 204 (102 high persisting, 102 low persisting) male outpatients. All groups were divided into equal halves in order to allow for cross-validation of three separate discriminant functions: One for males, one for females, and one for the entire sample (male + female). Cross-validation revealed that only the discriminant function for males achieved a classification accuracy (60%) greater than chance expectations. A series of biserial correlations indicated that male persisters tended to be less defensive while experiencing greater distress and that female persisters tended to be more introverted and less impulsive relative to their respective low-persisting counterparts.

First offender adult shoplifters: a preliminary profile.

Ninety-four adult first offender shoplifters completed a battery of psychological tests prior to their involvement in a novel and innovative West Texas Shoplifter Offenders Program (SOP). Analysis of the test results indicated that the modal shoplifter is female, Hispanic, and is likely to evidence a subclinical 8-4 high-point pair on the MMPI. Males tend to act more impulsively than females in their shoplifting styles. Shoplifters are no more likely to endorse irrational beliefs than normative groups. However, shoplifters tend to be rather anxious, depressed, and self-doubting. The results are discussed in terms of conceptual implications for SOP design and implementation.