1,221 research outputs found
Space Station
The official start of a bold new space program, essential to maintain the United States' leadership in space was signaled by a Presidential directive to move aggressively again into space by proceeding with the development of a space station. Development concepts for a permanently manned space station are discussed. Reasons for establishing an inhabited space station are given. Cost estimates and timetables are also cited
Apollo 17: At Taurus Littrow
A summation, with color illustrations, is presented on the Apollo 17 mission. The height, weight, and thrust specifications are given on the launch vehicle. Presentations are given on: the night launch; earth to moon ascent; separation and descent; EVA, the sixth lunar surface expedition; ascent from Taurus-Littrow; the America to Challenger rendezvous; return, reentry, and recovery; the scientific results of the mission; background information on the astronauts; and the future projects
On the determinants of euro area FDI to the United States: the knowledge- capital-Tobin's Q framework
The long-run determinants of euro area FDI to the United States during the period 1980-2001 are explained by employing the Tobin's Q-model of investment. By using the fixed effects panel estimator, stock market developments in the euro area countries - including a measure adjusted for economic developments common to both the United States and the euro area - are found to influence euro area FDI to the United States. Moreover, the inclusion of the Tobin's Q enhances the traditional knowledge-capital framework specification. Overall, the empirical findings suggest that euro area patents (ownership advantage), various variables related to productivity in the United States (location advantage), the volume of bilateral telephone traffic to the United States relative to euro area GDP (ownership advantage), euro area stock market developments (Tobin's Q), and the real exchange rate are statistically significant determinants of euro area FDI to the United States. JEL Classification: F21, F23euro area, Foreign Direct Investment, Multinational firms, Tobins Q
Sixty years of aeronautical research, 1917-1977
The history of Langley Research Center and its contributions to solving problems related to flight over the past six decades is recounted. Technical innovations described include those related to air craft construction materials, jet and rocket propulsion, flight testing and simulation, wind tunnel tests, noise reduction, supersonic flight, air traffic control, structural analysis, computational aerodynamics, and fuel efficiency
NASA aeronautics
Aeronautical research programs are discussed in relation to research methods and the status of the programs. The energy efficient aircraft, STOL aircraft and general aviation aircraft are considered. Aerodynamic concepts, rotary wing aircraft, aircraft safety, noise reduction, and aircraft configurations are among the topics included
Sleep disturbance and serum ferritin levels associate with high impulsivity and impulse control disorders in male Parkinson\u27s Disease patients
Impulse control disorders (ICDs) occur in a subset of Parkinsonās disease (PD) patients on dopaminergic medications however there are currently no reliable markers to identify patients at risk. Sleep disturbances are more common in patients with an ICD. Serum ferritin levels have been associated with PD disease stage and progression, but have not previously been associated with impulsivity levels. The objective of this study was to determine if serum ferritin levels and sleep disturbance are associated with high traits of impulsivity and ICD in a cohort of PD patients attending a movement disorders clinic. This study assessed impulsiveness in 87 PD patients using the Barratt Impulsiveness Scale. Severity of sleep disturbance was determined using the sleep-related items of the MDS-UPDRS. Serum ferritin, iron and transferrin levels were measured in patients, as well as 36 age-matched healthy controls. Serum ferritin levels were significantly elevated in male PD patients in the high impulsivity group compared to patients in the low (p=.022) and normal range groups (p=.024) and showed a linear increase across the three groups. Sleep disturbance also demonstrated a linear trend, which was most severe in the high impulsivity group (p=.030). A subgroup of 11 male PD patients who fulfilled the DSM-5 criteria for an ICD had significantly higher ferritin levels and more severe sleep disturbance when compared with the remaining male PD cohort. Serum ferritin levels and sleep disturbance severity are highlighted as potential markers for abnormal impulsivity and ICD in PD patients
Extended Timed Up and Go assessment as a clinical indicator of cognitive state in Parkinson\u27s disease
Objective: To evaluate a modified extended Timed Up and Go (extended-TUG) assessment against a panel of validated clinical assessments, as an indicator of Parkinsonās disease (PD) severity and cognitive impairment.
Methods: Eighty-seven participants with idiopathic PD were sequentially recruited from a Movement Disorders Clinic. An extended-TUG assessment was employed which required participants to stand from a seated position, walk in a straight line for 7 metres, turn 180 degrees and then return to the start, in a seated position. The extended-TUG assessment duration was correlated to a panel of clinical assessments, including the Unified Parkinsonās Disease Rating Scale (MDS-UPDRS), Quality of Life (PDQ-39), Scales for Outcomes in Parkinsonās disease (SCOPA-Cog), revised Addenbrookeās Cognitive Index (ACE-R) and Barrattās Impulsivity Scale 11 (BIS-11).
Results: Extended-TUG time was significantly correlated to MDS-UPDRS III score and to SCOPA-Cog, ACE-R (p\u3c0.001) and PDQ-39 scores (p\u3c0.01). Generalized linear models determined the extended-TUG to be a sole variable in predicting ACE-R or SCOPA-Cog scores. Patients in the fastest extended-TUG tertile were predicted to perform 8.3 and 13.4 points better in the SCOPA-Cog and ACE-R assessments, respectively, than the slowest group. Patients who exceeded the dementia cut-off scores with these instruments exhibited significantly longer extended-TUG times.
Conclusions: Extended-TUG performance appears to be a useful indicator of cognition as well as motor function and quality of life in PD, and warrants further evaluation as a first line assessment tool to monitor disease severity and response to treatment. Poor extended-TUG performance may identify patients without overt cognitive impairment form whom cognitive assessment is needed
Stress and Sleep Quality: Mediating Effects of Social Support
Stress is defined as the ānonspecific response of the body to any demand made upon itā (Kohn & Frazer, 1986). Stress is among the top five threats to academic performance among college students (Pettit & DeBarr, 2011). The purpose of the study was to investigate whether stress affects perceived sleep quality, as mediated by social support, and to determine whether stress levels vary based on academic major. Using ANOVA in SPSS 24, we tested three hypotheses: stress and sleep quality are negatively correlated, social support mediates the relationship between stress and sleep quality, and stress levels will vary by academic major (specifically that science, technology, engineering, and mathematics majors will show greater perceived amounts of stress). Results of this study show that there is positive correlation between sleep and stress, a negative correlation between social support and sleep, and a negative correlation between stress and social support
Tolerance without clonal expansion: Self-antigen-expressing B cells program self-reactive T cells for future deletion
B cells have been shown in various animal models to induce immunological tolerance leading to reduced immune responses and protection from autoimmunity. We show that interaction of B cells with naive T cells results in T cell triggering accompanied by the expression of negative costimulatory molecules such as PD-1, CTLA-4, B and T lymphocyte attenuator, and CD5. Following interaction with B cells, T cells were not induced to proliferate, in a process that was dependent on their expression of PD-1 and CTLA-4, but not CD5. In contrast, the T cells became sensitive to Ag-induced cell death. Our results demonstrate that B cells participate in the homeostasis of the immune system by ablation of conventional self-reactive T cells
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