6,285 research outputs found
Adaptation to transient postural perturbations
This research was first proposed in May, 1986, to focus on some of the problems encountered in the analysis of postural responses gathered from crewmembers. The ultimate driving force behind this line of research was the desire to treat, predict, or explain 'Space Adaptation Syndrome' (SAS) and hence circumvent any adverse effects of space motion sickness on crewmember performance. The aim of this project was to develop an easily implemented analysis of the transient responses to platform translation that can be elicited with a protocol designed to force sensorimotor reorganization, utilizing statistically reliable criterion measures. This report will present: (1) a summary of the activity that took place in each of the three funded years of the project; (2) discussion of experimental results and their implications for future research; and (3) a list of presentations and publications resulting from this project
Economic instability and aggregate investment
Recent literature suggests that because investment expenditures are irreversible and can be delayed, they may be highly sensitive to uncertainty. The authors briefly summarize the theory, stressing its empirical implications. Then, using cross-section and time-series data for a set of developing and industrial countries, they explore the empirical relevance of irreversibility and uncertainty to aggregate investment. They find that: (a) the volatility of the marginal profitability of capital (a summary measure of uncertainty) affects investment as the theory suggests, but the effect is moderate, and greatest for developing countries; (b)this volatility has little correlation with indices of political instability used in recent studies of growth; (c) inflation is highly correlated with this volatility and is a robust determinant of investment and the marginal profitability ofcapital. The volatility of the real exchange rate also has an independent contribution in explaining investment; and (d) the relationship between inflation and investment is nonlinear, and different thresholds of inflation, where the relationship with investment becomes stronger, were detected for a group of high-inflation countries in Latin America and low-inflation economies in the Organization for Economic Cooperation and Development (OECD).Economic Theory&Research,Environmental Economics&Policies,International Terrorism&Counterterrorism,Banks&Banking Reform,ICT Policy and Strategies
Bessel Functions in Mass Action. Modeling of Memories and Remembrances
Data from experimental observations of a class of neurological processes
(Freeman K-sets) present functional distribution reproducing Bessel function
behavior. We model such processes with couples of damped/amplified oscillators
which provide time dependent representation of Bessel equation. The root loci
of poles and zeros conform to solutions of K-sets. Some light is shed on the
problem of filling the gap between the cellular level dynamics and the brain
functional activity. Breakdown of time-reversal symmetry is related with the
cortex thermodynamic features. This provides a possible mechanism to deduce
lifetime of recorded memory.Comment: 16 pages, 9 figures, Physics Letters A, 2015 in pres
Recommended from our members
Patients with ALS show highly correlated progression rates in left and right limb muscles.
ObjectiveAmyotrophic lateral sclerosis (ALS) progresses at different rates between patients, making clinical trial design difficult and dependent on large cohorts of patients. Currently, there are few data showing whether the left and right limbs progress at the same or different rates. This study addresses rates of decline in specific muscle groups of patients with ALS and assesses whether there is a relationship between left and right muscles in the same patient, regardless of overall progression.MethodsA large cohort of patients was used to assess decline in muscle strength in right and left limbs over time using 2 different methods: The Tufts Quantitative Neuromuscular Exam and Accurate Test of Limb Isometric Strength protocol. Then advanced linear regression statistical methods were applied to assess progression rates in each limb.ResultsThis report shows that linearized progression models can predict general slopes of decline with good accuracy. Critically, the data demonstrate that while overall decline is variable, there is a high degree of correlation between left and right muscle decline in ALS. This implies that irrespective of which muscle starts declining soonest or latest, their rates of decline following onset are more consistent.ConclusionsFirst, this study demonstrates a high degree of power when using unilateral treatment approaches to detect a slowing in disease progression in smaller groups of patients, thus allowing for paired statistical tests. These findings will be useful in transplantation trials that use muscle decline to track disease progression in ALS. Second, these findings discuss methods, such as tactical selection of muscle groups, which can improve the power efficiency of all ALS clinical trials
War, the United Nations, and Peacekeeping
While the amount of interstate war in the international system had declined by 2013, since then both intrastate and internationalized intrastate war has increased. In 2015 there are sixteen UN peacekeeping operations around the globe, involving about 130,000 military, police, and civilian personnel. Over the past seventy years, UN peacekeeping operations have evolved from simple buffer forces tasked with observing cease-fires and armistices to complex multidimensional operations in intrastate conflicts, involving peacebuilding in an increasingly dangerous environment
- …