592 research outputs found

    Gold Standards Training and Evaluator Calibration of Pilot School Check Instructors

    Get PDF
    A key component of air carrier advanced qualification programs is the calibration and training of instructors and evaluators and assurance of reliable and valid data in support of such programs. A significant amount of research is available concerning the calibration of air carrier evaluators, but no research exists regarding the calibration of pilot school check instructors. This study was designed to determine if pilot school check instructors can be calibrated against a gold standard to perform reliable and accurate evaluations. Calibration followed the principles and theories of andragogy and adult learning and teaching, including emphasis on the cognitive domain of learning, learnercentered instruction, and human resource development. These in combination with methods commonly used in aviation instruction aimed to increase the effectiveness of the calibration. Discussion of these combinations is included. A specific method for delivery of the calibration was provided along with a complete lesson plan. This study used a one group pretest-posttest design. A group of 10 pilot school check instructors were measured before and after receiving rater calibration training. Statistical measures included raw inter- and referent-rater agreement percentages, Cohen’s kappa and kappa-like statistics for inter- and referent-rater reliability, Pearson product-moment correlations for sensitivity to true changes in pilot performance, and a standardized mean absolute difference for grading accuracy. Improvement in all the measurements from pretest to posttest was expected, but actual results were mixed. However, a holistic interpretation of the results combined with feedback from the check instructors showed promise in calibration training for pilot school check instructors. Thorough discussion of the limitations and lessons learned from the study, recommendations for pilot schools, and recommendations for future research is included

    Evaluating the Effectiveness of Game-Based Virtual Reality in Satellite Ground Control Operations Education and Training

    Get PDF
    There is increased global demand for satellite amenities such as navigation, communications, weather reporting, disaster management, agricultural operations, or humanitarian assistance. The growing demand for satellite technology amplifies the need for highly trained satellite operators. Traditional simulation training methods typically utilize two-dimensional computer displays. However, training approaches involving game-based instruction and immersive virtual reality have shown benefits when integrated with complex disciplines and may provide an advanced training alternative for satellite operators. Game-based instruction enhances user motivation and cognitive engagement, while immersive virtual reality promotes user presence and prolonged cognitive engagement. The combination of these two training methods, noted as game-based virtual reality, is explored in this study when integrated with a satellite operator training scenario. The study compares two groups, one training with traditional methods and one with game-based virtual reality. Both scenarios indicated significant usability scores and proper cognitive loading necessary for meaningful learning, with only minimal symptoms of simulator sickness. However, unlike the traditional method, the results of the game-based virtual reality scenario revealed significant user enjoyment and satisfaction scores. A positive and satisfying learning experience can facilitate enhanced motivation and increased cognitive engagement, fundamental to meaningful learning, denoting game-based virtual reality as a viable and effective training alternative

    Dopaminergic, serotonergic, and noradrenergic deficits in Parkinson disease

    Get PDF
    OBJECTIVE: People with Parkinson disease (PD) frequently develop dementia, which is associated with neocortical deposition of alpha-synuclein (α-syn) in Lewy bodies and Lewy neurites. In addition, neuronal loss and deposition of aggregated α-syn also occur in multiple subcortical nuclei that project to neocortical, limbic, and basal ganglia regions. Therefore, we quantified regional deficits in innervation from these PD-affected subcortical nuclei, by measuring the neurotransmitters and neurotransmitter transporter proteins originating from projections of dopaminergic neurons in substantia nigra pars compacta, serotonergic neurons in dorsal raphé nuclei, noradrenergic neurons in locus coeruleus, and cholinergic neurons in nucleus basalis of Meynert. METHODS: High-performance liquid chromatography and novel enzyme-linked immunosorbent assays were performed to quantify dopaminergic, serotonergic, noradrenergic, and cholinergic innervation in postmortem brain tissue. Eight brain regions from 15 PD participants (with dementia and Braak stage 6 α-syn deposition) and six age-matched controls were tested. RESULTS: PD participants compared to controls had widespread reductions of dopamine transporter in caudate, amygdala, hippocampus, inferior parietal lobule (IPL), precuneus, and visual association cortex (VAC) that exceeded loss of dopamine, which was only significantly reduced in caudate and amygdala. In contrast, PD participants had comparable deficits of both serotonin and serotonin transporter in caudate, middle frontal gyrus, IPL, and VAC. PD participants also had significantly reduced norepinephrine levels for all eight brain regions tested. Vesicular acetylcholine transporter levels were only quantifiable in caudate and hippocampus and did not differ between PD and control groups. INTERPRETATION: These results demonstrate widespread deficits in dopaminergic, serotonergic, and noradrenergic innervation of neocortical, limbic, and basal ganglia regions in advanced PD with dementia

    Fluselenamyl: A novel benzoselenazole derivative for PET detection if amyloid plaques (Aβ) in Alzheimer\u27s disease

    Get PDF
    Fluselenamyl (5), a novel planar benzoselenazole shows traits desirable of enabling noninvasive imaging of Aβ pathophysiology in vivo; labeling of both diffuse (an earlier manifestation of neuritic plaques) and fibrillar plaques in Alzheimer’s disease (AD) brain sections, and remarkable specificity for mapping Aβ compared with biomarker proteins of other neurodegenerative diseases. Employing AD homogenates, [(18)F]-9, a PET tracer demonstrates superior (2–10 fold higher) binding affinity than approved FDA tracers, while also indicating binding to high affinity site on Aβ plaques. Pharmacokinetic studies indicate high initial influx of [(18)F]-9 in normal mice brains accompanied by rapid clearance in the absence of targeted plaques. Following incubation in human serum, [(18)F]-9 indicates presence of parental compound up to 3h thus indicating its stability. Furthermore, in vitro autoradiography studies of [(18)F]-9 with AD brain tissue sections and ex vivo autoradiography studies in transgenic mouse brain sections show cortical Aβ binding, and a fair correlation with Aβ immunostaining. Finally, multiphoton- and microPET/CT imaging indicate its ability to penetrate brain and label parenchymal plaques in transgenic mice. Following further validation of its performance in other AD rodent models and nonhuman primates, Fluselenamyl could offer a platform technology for monitoring earliest stages of Aβ pathophysiology in vivo

    Effectiveness of single dose rifampicin in preventing leprosy in close contacts of patients with newly diagnosed leprosy

    Get PDF
    Objective To determine the effectiveness of chemoprophylaxis using a single dose of rifampicin to prevent leprosy in close contacts. Design Single centre, double blind, cluster randomised, placebo controlled trial. SettingLeprosy control programme in two districts of northwest Bangladesh with a population of more than four million. Participants28 092 close contacts of 1037 patients with newly diagnosed leprosy. 21 711 contacts fulfilled the study requirements. Interventions A single dose of rifampicin or placebo given to close contacts in the second month of starting the index patient’s treatment, with follow-up for four years. Main outcome measure Development of clinical leprosy. Results 18 869 of the 21 711 contacts (86.9%) were followed-up at four years. Ninety one of 9452 contacts in the placebo group and 59 of 9417 in the rifampicin group had developed leprosy. The overall reduction in incidence of leprosy using a single dose of rifampicin in the first two years was 57% (95% confidence interval 33% to 72%). The groups did not differ between two and four years. The overall number needed to treat (NNT) to prevent a single case of leprosy among contacts was 297 (95% confidence interval 176 to 537). Differences were found between subgroups at two years, both in reduction of incidence and in NNT. ConclusionA single dose of rifampicin given to contacts of patients with newly diagnosed leprosy is effective at preventing the development of clinical leprosy at two years. The effect was maintained, but no difference was seen between the placebo and rifampicin groups beyond two years. Trial registration Current Controlled Trials ISRCTN61223447

    Role of surface roughness in hard x-ray emission from femtosecond laser produced copper plasmas

    Get PDF
    The hard x-ray emission in the energy range of 30-300 keV from copper plasmas produced by 100 fs, 806 nm laser pulses at intensities in the range of 10151016^{15}-10^{16} W cm2^{-2} is investigated. We demonstrate that surface roughness of the targets overrides the role of polarization state in the coupling of light to the plasma. We further show that surface roughness has a significant role in enhancing the x-ray emission in the above mentioned energy range.Comment: 5 pages, 4 figures, to appear in Phys. Rev.

    Impact of the Alzheimer's Disease Neuroimaging Initiative, 2004 to 2014

    Get PDF
    INTRODUCTION: The Alzheimer's Disease Neuroimaging Initiative (ADNI) was established in 2004 to facilitate the development of effective treatments for Alzheimer's disease (AD) by validating biomarkers for AD clinical trials. METHODS: We searched for ADNI publications using established methods. RESULTS: ADNI has (1) developed standardized biomarkers for use in clinical trial subject selection and as surrogate outcome measures; (2) standardized protocols for use across multiple centers; (3) initiated worldwide ADNI; (4) inspired initiatives investigating traumatic brain injury and post-traumatic stress disorder in military populations, and depression, respectively, as an AD risk factor; (5) acted as a data-sharing model; (6) generated data used in over 600 publications, leading to the identification of novel AD risk alleles, and an understanding of the relationship between biomarkers and AD progression; and (7) inspired other public-private partnerships developing biomarkers for Parkinson's disease and multiple sclerosis. DISCUSSION: ADNI has made myriad impacts in its first decade. A competitive renewal of the project in 2015 would see the use of newly developed tau imaging ligands, and the continued development of recruitment strategies and outcome measures for clinical trials

    Quantifying regional α -synuclein, amyloid β, and tau accumulation in Lewy body dementia

    Get PDF
    OBJECTIVE: Parkinson disease (PD) is defined by the accumulation of misfolded α-synuclein (α-syn) in Lewy bodies and Lewy neurites. It affects multiple cortical and subcortical neuronal populations. The majority of people with PD develop dementia, which is associated with Lewy bodies in neocortex and referred to as Lewy body dementia (LBD). Other neuropathologic changes, including amyloid β (Aβ) and tau accumulation, occur in some LBD cases. We sought to quantify α-syn, Aβ, and tau accumulation in neocortical, limbic, and basal ganglia regions. METHODS: We isolated insoluble protein from fresh frozen postmortem brain tissue samples for eight brains regions from 15 LBD, seven Alzheimer disease (AD), and six control cases. We measured insoluble α-syn, Aβ, and tau with recently developed sandwich ELISAs. RESULTS: We detected a wide range of insoluble α-syn accumulation in LBD cases. The majority had substantial α-syn accumulation in most regions, and dementia severity correlated with neocortical α-syn. However, three cases had low neocortical levels that were indistinguishable from controls. Eight LBD cases had substantial Aβ accumulation, although the mean Aβ level in LBD was lower than in AD. The presence of Aβ was associated with greater α-syn accumulation. Tau accumulation accompanied Aβ in only one LBD case. INTERPRETATION: LBD is associated with insoluble α-syn accumulation in neocortical regions, but the relatively low neocortical levels in some cases suggest that other changes contribute to impaired function, such as loss of neocortical innervation from subcortical regions. The correlation between Aβ and α-syn accumulation suggests a pathophysiologic relationship between these two processes
    corecore