78 research outputs found
Ultra-High Energy Cosmic Ray Nuclei from Individual Magnetized Sources
We investigate the dependence of composition, spectrum and angular
distributions of ultra-high energy cosmic rays above 10^19 eV from individual
sources on their magnetization. We find that, especially for sources within a
few megaparsecs from the observer, observable spectra and composition are
severely modified if the source is surrounded by fields of ~ 10^-7 Gauss on
scales of a few megaparsecs. Low energy particles diffuse over larger distances
during their energy loss time. This leads to considerable hardening of the
spectrum up to the energy where the loss distance becomes comparable to the
source distance. Magnetized sources thus have very important consequences for
observations, even if cosmic rays arrive within a few degrees from the source
direction. At the same time, details in spectra and chemical composition may be
intrinsically unpredictable because they depend on the unknown magnetic field
structure. If primaries are predominantly nuclei of atomic mass A accelerated
up to a maximum energy E_max with spectra not much softer than E^-2, secondary
protons from photo-disintegration can produce a conspicuous peak in the
spectrum at energy ~ E_max/A. A related feature appears in the average mass
dependence on energy.Comment: 15 pages, 16 ps figures, published version with minor changes, see
http://stacks.iop.org/1475-7516/2004/i=08/a=01
Separation of Oligosaccharides from Lotus Seeds via Medium-pressure Liquid Chromatography Coupled with ELSD and DAD
peer-reviewedLotus seeds were identified by the Ministry of Public Health of China as both food and medicine. One general function of lotus seeds is to improve intestinal health. However, to date, studies evaluating the relationship between bioactive compounds in lotus seeds and the physiological activity of the intestine are limited. In the present study, by using medium pressure liquid chromatography coupled with evaporative light-scattering detector and diode-array detector, five oligosaccharides were isolated and their structures were further characterized by electrospray ionization-mass spectrometry and gas chromatography-mass spectrometry. In vitro testing determined that LOS3-1 and LOS4 elicited relatively good proliferative effects on Lactobacillus delbrueckii subsp. bulgaricus. These results indicated a structure-function relationship between the physiological activity of oligosaccharides in lotus seeds and the number of probiotics applied, thus providing room for improvement of this particular feature. Intestinal probiotics may potentially become a new effective drug target for the regulation of immunity
Blast Shock Wave Mitigation Using the Hydraulic Energy Redirection and Release Technology
A hydraulic energy redirection and release technology has been developed for mitigating the effects of blast shock waves on protected objects. The technology employs a liquid-filled plastic tubing as a blast overpressure transformer to transfer kinetic energy of blast shock waves into hydraulic energy in the plastic tubings. The hydraulic energy is redirected through the plastic tubings to the openings at the lower ends, and then is quickly released with the liquid flowing out through the openings. The samples of the specifically designed body armor in which the liquid-filled plastic tubings were installed vertically as the outer layer of the body armor were tested. The blast test results demonstrated that blast overpressure behind the body armor samples was remarkably reduced by 97% in 0.2 msec after the liquid flowed out of its appropriate volume through the openings. The results also suggested that a volumetric liquid surge might be created when kinetic energy of blast shock wave was transferred into hydraulic energy to cause a rapid physical movement or displacement of the liquid. The volumetric liquid surge has a strong destructive power, and can cause a noncontact, remote injury in humans (such as blast-induced traumatic brain injury and post-traumatic stress disorder) if it is created in cardiovascular system. The hydraulic energy redirection and release technology can successfully mitigate blast shock waves from the outer surface of the body armor. It should be further explored as an innovative approach to effectively protect against blast threats to civilian and military personnel
Randomized Controlled Trial of Fish Oil and Montelukast and Their Combination on Airway Inflammation and Hyperpnea-Induced Bronchoconstriction
Both fish oil and montelukast have been shown to reduce the severity of exercise-induced bronchoconstriction (EIB). The purpose of this study was to compare the effects of fish oil and montelukast, alone and in combination, on airway inflammation and bronchoconstriction induced by eucapnic voluntary hyperpnea (EVH) in asthmatics.
In this model of EIB, twenty asthmatic subjects with documented hyperpnea-induced bronchoconstriction (HIB) entered a randomized double-blind trial. All subjects entered on their usual diet (pre-treatment, n = 20) and then were randomly assigned to receive either one active 10 mg montelukast tablet and 10 placebo fish oil capsules (n = 10) or one placebo montelukast tablet and 10 active fish oil capsules totaling 3.2 g EPA and 2.0 g DHA (n = 10) taken daily for 3-wk. Thereafter, all subjects (combination treatment; n = 20) underwent another 3-wk treatment period consisting of a 10 mg active montelukast tablet or 10 active fish oil capsules taken daily.
While HIB was significantly inhibited (p0.017) between treatment groups; percent fall in forced expiratory volume in 1-sec was −18.4±2.1%, −9.3±2.8%, −11.6±2.8% and −10.8±1.7% on usual diet (pre-treatment), fish oil, montelukast and combination treatment respectively. All three treatments were associated with a significant reduction (p0.017) in these biomarkers between treatments.
While fish oil and montelukast are both effective in attenuating airway inflammation and HIB, combining fish oil with montelukast did not confer a greater protective effect than either intervention alone. Fish oil supplementation should be considered as an alternative treatment for EIB
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Time to establish an international vaccine candidate pool for potential highly infectious respiratory disease: a community's view.
In counteracting highly infectious and disruptive respiratory diseases such as COVID-19, vaccination remains the primary and safest way to prevent disease, reduce the severity of illness, and save lives. Unfortunately, vaccination is often not the first intervention deployed for a new pandemic, as it takes time to develop and test vaccines, and confirmation of safety requires a period of observation after vaccination to detect potential late-onset vaccine-associated adverse events. In the meantime, nonpharmacologic public health interventions such as mask-wearing and social distancing can provide some degree of protection. As climate change, with its environmental impacts on pathogen evolution and international mobility continue to rise, highly infectious respiratory diseases will likely emerge more frequently and their impact is expected to be substantial. How quickly a safe and efficacious vaccine can be deployed against rising infectious respiratory diseases may be the most important challenge that humanity will face in the near future. While some organizations are engaged in addressing the World Health Organization's "blueprint for priority diseases", the lack of worldwide preparedness, and the uncertainty around universal vaccine availability, remain major concerns. We therefore propose the establishment of an international candidate vaccine pool repository for potential respiratory diseases, supported by multiple stakeholders and countries that contribute facilities, technologies, and other medical and financial resources. The types and categories of candidate vaccines can be determined based on information from previous pandemics and epidemics. Each participant country or region can focus on developing one or a few vaccine types or categories, together covering most if not all possible potential infectious diseases. The safety of these vaccines can be tested using animal models. Information for effective candidates that can be potentially applied to humans will then be shared across all participants. When a new pandemic arises, these pre-selected and tested vaccines can be quickly tested in RCTs for human populations
Non-Industrial Private Forest Landowner Use of Information Sources Concerning Management of Their Woodland on the Tennessee Northern Cumberland Plateau
Recent studies have pointed towards non-industrial private forest landowners being underserved. This article presents data collected on the Tennessee Northern Cumberland Plateau in 2005 by the University of Tennessee to assess landowner use of information sources and employs an econometric model to assess landowner characteristics and how they affect what sources of information landowners are most likely to use. Results reveal that landowners have mostly used friends, family, and neighbors as information sources. Multinomial logistic regression results reveal that landowners may be motivated to actively manage their forestland but are not necessarily interested in Extension information
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Steel containment buckling. [PWR; BWR]
The Steel Containment Buckling program is in its fourth phase of work directed at the evaluation of the effects of the structural failure mode of steel containments when the membrane stresses are compressive. The structural failure mode for this state of stress is instability or buckling. The program to date has investigated: (1) the effect on overall buckling capacity of the ASME area replacement method for reinforcing around circular penetrations; (2) a set of benchmark experiments on ring-stiffened shells having reinforced and framed penetrations; (3) large and small scale experiments on knuckle region buckling from internal pressure and post-buckling behavior to failure for vessel heads having torispherical geometries; and (4) buckling under time-dependent loadings (dynamic buckling). The first two investigations are complete, the knuckle buckling experimental efforts are complete with data analysis and reporting in progress, and the dynamic buckling experimental and analytical work is in progress
Modeling Acceptance of a Shuttle System in the Great Smoky Mountains National Park
Visitation to the Cades Cove area of the Great Smoky Mountains National Park has grown approximately 300% in the last 20 years and has doubled since 1990. Approximately 2 million people visited Cades Cove in 2000, with 57% of this use occurring in the peak months of June-August and October (U.S. Department of the Interior, National Park Service, 2003). The 11-mile one-way loop road through the Cove is operating in a near gridlock condition through much of this time. Covering the 11 miles through the cove can take up to 4 to 6 hours as visitors block traffic by stopping in the middle of the road to view flora and fauna and take pictures. The impact of this high level of visitation on the quality of visitor experience, park resources, and facility capacity is of significant concern to park officials. Other national parks faced with similar issues have opted for greater access restrictions in favor of quality improvements resulting from less traffic congestion. Acadia National Park, Grand Canyon National Park, Yellowstone National Park, and Zion National Park have all instituted various shuttle systems to alleviate traffic congestion common during certain parts of the year. However, based on public perception of how national parks are visited, the establishment of such shuttle systems could potentially result in greater impact on visitor experience than that resulting from the increase in traffic congestion. Although public sentiment to reduce traffic congestion in Cades Cove has been great, transportation management has been a key point of contention, especially the proposed mandatory shuttle alternative. Some have argued that the cost of the proposed shuttle system is too great and that access to the area by private vehicles should not be limited. Others counter that the value they receive from their visit is being compromised due to increased traffic congestion. This study attempts to model the acceptance of a proposed shuttle system by Tennessee residents to determine how many/who supports a mandatory shuttle system in Cades Cove and the value residents place on reduced traffic congestion by way of a shuttle system. A random digit dial telephone survey was conducted to garner opinions on the use of a mandatory shuttle system to alleviate traffic congestion in Cades Cove. In addition, a dichotomous choice contingent valuation question was also posed to survey respondents to determine the value of reduced traffic congestion in Cades Cove. Results indicate that support for a mandatory shuttle system may be higher than first thought and that the value of reduced traffic congestion is significant
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