260 research outputs found
Fatigue in U.S. Astronauts Onboard the International Space Station: Environmental Factors, Operational Impacts, and Implementation of Countermeasures
Since 2000, US astronauts have been supporting missions up to a six month duration on the International Space Station (ISS). Crewmembers have experienced fatigue for reasons similar to military deployments. Astronauts experience psychological stressors such as heavy workloads, extended duty periods, circadian misalignment, inadequate/ineffective sleep, and loss of the environmental cues of a gravity environment. Complicating the psychological stressors are environmental factors; distracting background noise, unexpected and variable mission schedules, unfavorable thermal control, elevated CO2 levels, and an unusual sleep environment with schedules that impinge on presleep periods. Physiological contributors to poor sleep and fatigue include a cephalad fluid shift and back pain. Restful sleep is further challenged due to a lack of gravityrelated proprioceptive cues and need for restraints. The term "space fog" has been used by astronauts to describe a phenomenon of forgetfulness, slowed reaction time and transient confusion while trying to complete tasks. There is a distinct temporal correlation with arrival on the Space Station and the onset of slowed cognitive skills and a spontaneous resolution that may take up to 6 weeks. The Genesis of this phenomenon may be chronic fatigue secondary to transitioning from a planar environment to a 360deg microgravity perspective. Recently, countermeasures to improve sleep duration and quality in astronauts on the ISS have been instituted with moderate degrees of success as measured by selfreaction time (psychomotor vigilance task testing), actigraphy, and subjective reports. Judicious use of stimulants and hypnotics, light therapy, controlled sleep periods and sleep shifting and reducing ambient CO2 levels are a few of the most promising countermeasures being used in space to improve sleep and reduce fatigue
Practice patterns for acute ischemic stroke workup: A longitudinal populationâbased study
Background
We examined practice patterns of inpatient testing to identify stroke etiologies and treatable risk factors for acute ischemic stroke recurrence.
Methods and Results
We identified stroke cases and related diagnostic testing from four 1âyear study periods (July 1993 to June 1994, 1999, 2005, and 2010) of the Greater Cincinnati/Northern Kentucky Stroke Study. Patients aged â„18Â years were included. We focused on evaluation of extracranial arteries for carotid stenosis and assessment of atrial fibrillation because randomized controlled trials supported treatment of these conditions for stroke prevention across all 4 study periods. In each study period, we also recorded stroke etiology, as determined by diagnostic testing and physician adjudication. An increasing proportion of stroke patients received assessment of both extracranial arteries and the heart over time (50%, 58%, 74%, and 78% in the 1993â1994, 1999, 2005, and 2010 periods, respectively;
P
<0.0001 for trend), with the most dramatic individual increases in echocardiography (57%, 63%, 77%, and 83%, respectively). Concurrently, we observed a decrease in strokes of unknown etiology (47%, 48%, 41%, and 38%, respectively;
P
<0.0001 for trend). We also found a significant increase in strokes of other known causes (32%, 25%, 45% and 59%, respectively;
P
<0.0001 for trend).
Conclusions
Stroke workup for treatable causes of stroke are being used more frequently over time, and this is associated with a decrease in cryptogenic strokes. Future study of whether better determination of treatable stroke etiologies translates to a decrease in stroke recurrence at the population level will be essential.
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Fatigue in U.S. Astronauts Onboard the International Space Station: Environmental factors, Operational Impacts, and Implementation of Countermeasures
Crewmembers have experienced fatigue for reasons similar to military deployments. Astronauts experience psychological stressors such as: heavy workloads, extended duty periods, circadian misalignment, inadequate/ineffective sleep, distracting background noise, unexpected and variable mission schedules, unfavorable thermal control, unusual sleep environment with schedules that impinge on presleep periods
Three-dimensional structure of an immunoglobulin light-chain dimer with amyloidogenic properties
The X-ray structure of an immunoglobulin light-chain dimer isolated from the urine as a 'Bence-Jones protein' from a patient with multiple myeloma and amyloidosis (Sea) was determined at 1.94 Angstrom resolution and refined to R and R-free factors of 0.22 and 0.25, respectively. This 'amyloidogenic' protein crystallized in the orthorhombic P2(1)2(1)2(1) space group with unit-cell parameters a=48.28, b=83.32, c=112.59 Angstrom as determined at 100 K. In the vital organs (heart and kidneys), the equivalent of the urinary protein produced fibrillar amyloid deposits which were fatal to the patient. Compared with the amyloidogenic Mcg light-chain dimer, the Sea protein was highly soluble in aqueous solutions and only crystallized at concentrations approaching 100 mg ml(-1). Both the Sea and Mcg proteins packed into crystals in highly ordered arrangements typical of strongly diffracting crystals of immunoglobulin fragments. Overall similarities and significant differences in the three-dimensional structures and crystalline properties are discussed for the Sea and Mcg Bence-Jones proteins, which together provide a generalized model of abnormalities present in lambda chains, facilitating a better understanding of amyloidosis of light-chain origin (AL)
World scientistsâ warnings into action, local to global
âWe have kicked the can down the road once again â but we are running out of road.â â Rachel Kyte, Dean of Fletcher School at Tufts University. We, in our capacities as scientists, economists, governance and policy specialists, are shifting from warnings to guidance for action before there is no more âroad.â The science is clear and irrefutable; humanity is in advanced ecological overshoot. Our overexploitation of resources exceeds ecosystemsâ capacity to provide them or to absorb our waste. Society has failed to meet clearly stated goals of the UN Framework Convention on Climate Change. Civilization faces an epochal crossroads, but with potentially much better, wiser outcomes if we act now. What are the concrete and transformative actions by which we can turn away from the abyss? In this paper we forcefully recommend priority actions and resource allocation to avert the worst of the climate and nature emergencies, two of the most pressing symptoms of overshoot, and lead society into a future of greater wellbeing and wisdom. Humanity has begun the social, economic, political and technological initiatives needed for this transformation. Now, massive upscaling and acceleration of these actions and collaborations are essential before irreversible tipping points are crossed in the coming decade. We still can overcome significant societal, political and economic barriers of our own making. Previously, we identified six core areas for urgent global action â energy, pollutants, nature, food systems, population stabilization and economic goals. Here we identify an indicative, systemic and time-limited framework for priority actions for policy, planning and management at multiple scales from household to global. We broadly follow the âReduce-Remove-Repairâ approach to rapid action. To guide decision makers, planners, managers, and budgeters, we cite some of the many experiments, mechanisms and resources in order to facilitate rapid global adoption of effective solutions. Our biggest challenges are not technical, but social, economic, political and behavioral. To have hope of success, we must accelerate collaborative actions across scales, in different cultures and governance systems, while maintaining adequate social, economic and political stability. Effective and timely actions are still achievable on many, though not all fronts. Such change will mean the difference for billions of children and adults, hundreds of thousands of species, health of many ecosystems, and will determine our common future
Stable incidence but declining case-fatality rates of subarachnoid hemorrhage in a population
Objective:
To characterize temporal trends in subarachnoid hemorrhage (SAH) incidence and outcomes over 5 time periods in a large population-based stroke study in the United States.
Methods:
All SAHs among residents of the Greater Cincinnati/Northern Kentucky region at least 20 years of age were identified and verified via study physician review in 5 distinct year-long study periods between 1988 and 2010. We abstracted demographics, care patterns, and outcomes, and we compared incidence and case-fatality rates across the study periods.
Results:
The incidence of SAH in the 5 study periods (age-, race-, and sex-adjusted to the 2000 US population) was 8.8 (95% confidence interval 6.8â10.7), 9.2 (7.2â11.2), 10.0 (8.0â12.0), 9.0 (7.1â10.9), and 7.7 (6.0â9.4) per 100,000, respectively; the trend in incidence rates from 1988 to 2010 was not statistically significant (p = 0.22). Advanced neurovascular imaging, endovascular coiling, and neurologic intensive care unit availability increased significantly over time. All-cause 5-day (32%â18%, p = 0.01; for trend), 30-day (46%â25%, p = 0.001), and 90-day (49%â29%, p = 0.001) case-fatality rates declined from 1988 to 2010. When we included only proven or highly likely aneurysmal SAH, the declines in case-fatality were no longer statistically significant.
Conclusions:
Although the incidence of SAH remained stable in this population-based region, 5-day, 30-day, and 90-day case-fatality rates declined significantly. Advances in surgical and medical management, along with systems-based changes such as the emergence of neurocritical care units, are potential explanations for the reduced case-fatality
Sex differences in cardiovascular risk profiles of ischemic stroke patients with diabetes in the Greater Cincinnati/Northern Kentucky Stroke Study
Background
The aim of the present study was to compare sex-specific associations between cardiovascular risk factors and diabetes mellitus (DM) among patients with acute ischemic stroke (AIS) in the Greater Cincinnati/Northern Kentucky Stroke Study (GCNKSS).
Methods
The GCNKSS ascertained AIS cases in 2005 and 2010 among adult (ageââ„â20âyears) residents of a biracial population of 1.3âmillion. Past and current stroke risk factors were compared between those with and without DM using Chi-squared tests and multiple logistic regression analysis to examine sex-specific profiles.
Results
There were 3515 patients with incident AIS; 1919 (55%) were female, 697 (20%) were Black, and 1146 (33%) had DM. Among both women and men with DM, significantly more were obese and had hypertension, high cholesterol, and coronary artery disease (CAD) compared with those without DM. For women with AIS, multivariable sex-specific adjusted analyses revealed that older age was associated with decreased odds of having DM (adjusted odds ratio [aOR] 0.88, 95% confidence interval [CI] 0.80â0.98). For women with CAD, the odds of DM were increased (aOR 1.76, 95% CI 1.33â2.32). Age and CAD were not significant factors in differentiating the profiles of men with and without DM.
Conclusions
Women with DM had strokes at a younger age, whereas no such age difference existed in men. Compared with men, women with DM were also more likely to have CAD than those without DM, suggesting a sex difference in the association between DM and vascular disease. These findings may suggest a need for more aggressive risk factor management in diabetic women
Production Externalities in the Wood Furniture Industry in Central Java
This paper exploits micro firm level data to examine the impact of spatial clustering and links to foreign buyer networks on firm performance in the wood furniture industry in Central Java, Indonesia. The analysis is based on an annual manufacturing survey. We identify the impact of specialization of the cluster, diversification, and links to foreign buyer networks. For this purpose, a production function framework is developed. The results lend support to the view that clustering of large and medium scale specialized firms improves firm performance, while clustering of small scale specialized firms and clustering of diverse firms are not conducive to firm performance. We also find a clear positive association between involvement in exporting activities and firm performance
Accuracy and precision in quantitative fluorescence microscopy
The light microscope has long been used to document the localization of fluorescent molecules in cell biology research. With advances in digital cameras and the discovery and development of genetically encoded fluorophores, there has been a huge increase in the use of fluorescence microscopy to quantify spatial and temporal measurements of fluorescent molecules in biological specimens. Whether simply comparing the relative intensities of two fluorescent specimens, or using advanced techniques like Förster resonance energy transfer (FRET) or fluorescence recovery after photobleaching (FRAP), quantitation of fluorescence requires a thorough understanding of the limitations of and proper use of the different components of the imaging system. Here, I focus on the parameters of digital image acquisition that affect the accuracy and precision of quantitative fluorescence microscopy measurements
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