1,761 research outputs found
The relationship between Saturn kilometric radiation and the solar wind
Voyager spacecraft radio, interplanetary plasma, and interplanetary magnetic field data are used to show that large amplitude fluctuations in the power generated by the Saturn kilometric radio emission are best correlated with solar wind ram pressure variation. In all, thirteen solar wind quantities previously found important in driving terrestrial magnetospheric substorms and other auroral processes were examined for evidence of correlations with the Saturn radio emission. The results are consistent with hydromagnetic wave or eddy diffusion processes driven by large scale solar wind pressure changes at Saturn's dayside magnetopause
Is Radial Extracorporeal Shock Wave Therapy an Effective Treatment for Chronic Plantar Fasciitis in Adults?
OBJECTIVE: The objective of this selective EBM review is to determine whether or not radial extracorporeal shock wave therapy (ESWT) is an effective treatment in adults with chronic plantar fasciitis.
STUDY DESIGN: Review of three English language primary studies published between 2008 and 2010.
DATA SOURCES: Two randomized control trials and one cohort study analyzing the effects of radial extracorporeal shock wave therapy on chronic plantar fasciitis were found using the OVID, Medline and Cochrane Databases.
OUTCOMES MEASURED: Each of the three studies measured improvement in pain from baseline after patients were treated with ESWT. Pain levels were quantified using a Visual Analog Scale (VAS). The VAS score assigned by each patient was a subjective pain severity score ranging from 0 (no pain) to 10 (worst possible pain).
RESULTS: The dichotomous data from the Gerdesmeyer et al. study and the Ibrahim et al. study showed statistically significant treatment success rates with the use of extracorporeal shock wave therapy to treat plantar fasciitis pain when compared to the control group, as determined by improvement in Visual Analog Scale scores. The continuous data provided by the Hofling et al. study showed a statistically significant improvement in overall pain, maximum pain, and pain with daily activities after participants received ESWT as compared to their pain levels prior to treatment. The Hofling et al. study did not find the reduction of night pain after ESWT to be statistically significant.
CONCLUSIONS: Gerdesmeyer et al., Ibrahim et al., and Hofling et al. all provided data which showed statistically significant pain improvement following extracorporeal shock wave therapy in adult patients with chronic plantar fasciitis. This improvement was present in all three studies despite varying numbers of extracorporeal shock wave therapy treatment sessions and variable time frames between treatments. In order to maximize the efficacy of ESWT, continued research is needed to determine the optimal number of ESWT treatment sessions and the optimal time frame between treatment sessions
Spread of epileptiform activity in the immature rat neocortex studied with voltage-sensitive dyes and laser scanning microscopy
1. Adult rats and rats with a postnatal age of 3-29 days (PN 3-29) were used for the preparation of in vitro slices of the frontal neocortex. Epileptiform activity was induced by bath application of the gamma-aminobutyric acid-A (GABAA) receptor antagonists bicuculline or picrotoxin. 2. The voltage-sensitive dye RH 414 and a laser scanning microscope were used for multiple-site optical recordings of membrane potential changes associated with epileptiform activity. Optical signals were compared with simultaneously measured extra-cellular field potentials. 3. Optical signals could be reliably recorded for the duration of the experiments (2-4 h). Extracellular recordings of convulsant-induced paroxysmal depolarizing shifts (PDSs) in slices stained with RH 414 were comparable with those obtained in unstained slices. Changes in dye signals in response to reductions in extracellular calcium, addition of tetrodotoxin (TTX), or application of excitatory amino acid receptor antagonists indicate that the fluorescence changes correlate well with established electrophysiological measures of epileptiform activity. 4. In slices from adult animals, dye signals were observed at all recording sites. The response with the shortest latency occurred invariably at the site of stimulation, and activity spread rapidly in both vertical and horizontal directions. Spread was significantly faster in the vertical than in the horizontal direction. 5. Epileptiform activity was absent or only weakly expressed in slices from PN 3-9 animals. Activity was detectable predominantly in upper cortical layers. 6. Dye signals were observed at all measurement points in slices from PN 10-19 animals. In this age group, peak amplitude increased with spread of activity from lower to upper cortical layers. There was no significant difference between the speed of propagation in the vertical and in the horizontal directions. Spontaneous epileptiform activity occurred at a high rate in the PN 10-19 age group, and signals associated with spontaneous epileptiform events were largest in upper layers. 7. In the PN 10-19 age group, optical signals were characterized by the repetitive occurrence of PDS discharges superimposed on a sustained response. The amplitude of the sustained response decreased with increasing distance from the site of stimulation. Analysis of the latencies revealed that the superimposed PDS-like events were generated at multiple sites within the scanning area. Amplitude and rate of rise were largest in slices from PN 10-19 animals. These values declined with ongoing development
In-flight calibration of STEREO-B/WAVES antenna system
The STEREO/WAVES (SWAVES) experiment on board the two STEREO spacecraft
(Solar Terrestrial Relations Observatory) launched on 25 October 2006 is
dedicated to the measurement of the radio spectrum at frequencies between a few
kilohertz and 16 MHz. The SWAVES antenna system consists of 6 m long orthogonal
monopoles designed to measure the electric component of the radio waves. With
this configuration direction finding of radio sources and polarimetry (analysis
of the polarization state) of incident radio waves is possible. For the
evaluation of the SWAVES data the receiving properties of the antennas,
distorted by the radiation coupling with the spacecraft body and other onboard
devices, have to be known accurately. In the present context, these properties
are described by the antenna effective length vectors. We present the results
of an in-flight calibration of the SWAVES antennas using the observations of
the nonthermal terrestrial auroral kilometric radiation (AKR) during STEREO
roll maneuvers in an early stage of the mission. A least squares method
combined with a genetic algorithm was applied to find the effective length
vectors of the STEREO Behind (STEREO-B)/WAVES antennas in a quasi-static
frequency range () which fit best to the model
and observed AKR intensity profiles. The obtained results confirm the former
SWAVES antenna analysis by rheometry and numerical simulations. A final set of
antenna parameters is recommended as a basis for evaluations of the SWAVES
data
Collisional and viscous damping of MHD waves in partially ionized plasmas of the solar atmosphere
Magnetohydrodynamic (MHD) waves are widely considered as a possible source of heating for various parts of the outer solar atmosphere. Among the main energy dissipation mechanisms which convert the energy of damped MHD waves into thermal energy are collisional dissipation(resistivity) and viscosity. The presence of neutral atoms in the partially ionized plasmas of the solar photosphere, chromosphere and prominences enhances the efficiency of both these energy dissipation mechanisms.
A comparative study of the efficiency of MHD wave damping in solar plasmas due to collisional and viscous energy dissipation mechanisms is presented here. The damping rates are taken from Braginskii 1965 and applied to the VAL C model of the quiet Sun (Vernazza et al. 1981). These estimations show which of the mechanisms are dominant in which regions. In general the correct description of MHD wave damping requires the consideration of all energy dissipation mechanisms via the inclusion of the appropriate terms in the generalized Ohm’s law, the momentum, energy and induction equations. Specific forms of the generalized Ohm’s Law and induction equation are presented that are suitable for regions of the solar atmosphere which are
partially ionised
CONSUMER UNDERSTANDING AND USE OF HEALTH INFORMATION ON PRODUCT LABELS: MARKETING IMPLICATIONS FOR FUNCTIONAL FOOD
In recent years, the numbers of functional foods being developed and subjected to scientific evaluation have increased substantially. The main characteristic of functional foods that distinguishes them from conventional foods is the potential health benefit, which can be considered to be a credence attribute of product quality. Because this characteristic cannot be easily assessed even after consumption, an asymmetric information environment for health benefits has emerged where producers have more information than consumers. Thus the government intervenes by regulating the provision of health information on product labels in order to avoid potential market failures. The Food and Drug Administration (FDA) recently amended the way health claims on labels of conventional food and dietary supplements are managed. The new policy on qualified health claims allows claims to be made based on different levels of supporting scientific evidence. The policy goal is to encourage firms to make accurate, science-based claims about the health benefits of their products while helping consumers prevent disease and improve their health through sound dietary decisions using nutrition information. This marks a break from the previous environment where a lengthy approval process was argued to provide a road block for food firms wanting to market functional foods based on emerging evidence of diet to health links. This study has two objectives. First, to determine how consumers use health and nutrition information on food labels to form judgments about product quality, using the Elaboration Likelihood Model (ELM) as a theoretical framework. Second, to examine whether consumers can differentiate various levels of health claims, specifically the new qualified language, approved by FDA in 2003. It is interesting to determine whether consumers understand the different levels of scientific evidence supporting such claims and whether they can distinguish between the disclaimer languages used. Understanding how consumers use health and nutrition information on product labels has implications for both public policy and food manufacturers who use health claims as tools to market their products e.g., functional foods. This study used a still hypothetical functional food product a wheat cracker containing soy protein. It has been shown that soluble fiber and isoflavones, which can be found in wheat and soy products, respectively, independently help prevent the risk of several maladies including cancer and heart disease. A 5 (claim information on the front label a control condition and the four levels of qualified health claim) x 2 (information on Nutrition Facts) between-subjects factorial design was applied. Five versions of claim information were manipulated, including a control condition and four levels of qualified health claim. Each claim contained explicit relationships between nutrients and diseases i.e., isoflavones - heart disease and soluble fiber - cancers, but had different disclaimers explaining the level of scientific evidence supporting the claim. A report card was also included to inform consumers about the various claim levels, ranging from level A to D. Information on the Nutrition Facts panel was manipulated representing a "healthy" and an "unhealthy" version. Three hundred and seventy-two undergraduate students participated in the study, receiving extra credit for a Marketing class. Several multi-item scales are used as dependent variables, including attitude toward the product, buying intention, strength of evaluation about scientific studies to support claim, confidence about claim statement, perception of product's health benefit, and information search. A univariate analysis of variance (ANOVA) is conducted to test main and interaction effects among independent variables on a dependent variable. The results of this study suggest that consumers pay attention to information from all sources including the front label and Nutrition Facts panel. Even though it is shown that consumers react more positively to versions with health claims, there is no evidence to support the first hypothesis that consumers are more careful in evaluating product quality when health and nutrition information is present on the front package. Nevertheless, consumers are able to differentiate healthy products from unhealthy products, regardless of the presence of health and nutrition information on the front label. This study examines whether consumers understand and can distinguish various levels of qualified health claims. Although evidence suggests that consumers react differently to various claim levels, it is not clear whether people understand differences in the scientific support of these claims, as described in the disclaimer. Despite an increasing trend in attitude and purchase intention from the weakest claim (level D) to the strongest claim (level A), there is no statistically significant difference among claim levels when using measures of evaluation of strength of scientific studies, confidence about claim information, and perception of product's health benefit. From the public policy perspective, the results of this study can help determine how consumers evaluate health and nutrition information. It is shown that consumers do not overlook information from other parts of the label specifically the Nutrition Facts panel and that the presence of health and nutrition information on the front label is not likely to mislead consumers. The key issue here that needs further investigation is how to effectively provide information on the front label to consumers. FDA's goal is to permit the use of more, better, easily understood, and up-to-date scientific information about how dietary choices can affect consumers' health on food labels. It is important to identify optimal levels of qualified health claims, perhaps only two levels instead of four levels, so that consumers can distinguish and understand differences in terms of the scientific support for the claims and product benefits. As for the food industry, the results of this study can help food manufacturers decide what level of health and nutrition information they should provide to consumers. In addition to understanding the petitioning procedures for different claims, food firms must determine which, how, and when consumers understand and use health information in order to find the most efficient marketing communication channels.Health Economics and Policy,
Mineralogy of Tongue of the ocean sediments
The carbonate mineralogy of 25 short cores from the Tongue of the Ocean has been determined. Evidence presented in this paper indicates that carbonate mineralogy may reflect Pleistocene sea-level changes due to an increased contribution of low magnesium calcite from the subaerially exposed Bahama Banks when sea levels were low. It is suggested that this relationship of mineralogy to sea level may find wide application in the study of carbonate sedimentation in intermediate-depth water, proximal to carbonate banks
Smoothness-constrained time-lapse inversion of data from 3D resistivity surveys
Three-dimensional resistivity surveys and their associated inversion models are required to accurately resolve structures exhibiting very complex geology. In the same light, 3D resistivity surveys collected at multiple times are required to resolve temporally varying conditions. In this work we present 3D data sets, both synthetic and real, collected at different times. The large spatio-temporal data sets are then inverted simultaneously using a least-squares methodology that incorporates roughness filters in both the space and time domains. The spatial roughness filter constrains the model resistivity to vary smoothly in the x-, y- and z-directions. A temporal roughness filter is also applied that minimizes changes in the resistivity between successive temporal inversion models and the L-curve method is used to determine the optimum weights for both spatial and temporal roughness filters. We show that the use of the temporal roughness filter can accurately resolve changes in the resistivity even in the presence of noise. The L1- and L2-norm constraints for the temporal roughness filter are first examined using a synthetic model. The synthetic data test shows that the L1-norm temporal constraint produces significantly more accurate results when the resistivity changes abruptly with time. The model obtained with the L1-norm temporal constraint is also less sensitive to random noise compared with independent inversions (i.e., without any temporal constraint) and the L2-norm temporal constraint. Anomalies that are common in models using independent inversions and the L2-norm and L1-norm temporal constraints are likely to be real. In contrast, anomalies present in a model using independent inversions but that are significantly reduced with the L2-norm and L1-norm constraints are likely artefacts. For field data sets, the method successfully recovered temporal changes in the subsurface resistivity from a landfill monitoring survey due to rainwater infiltration, as well as from an experiment to map the migration of sodium cyanide solution from an injection well using surface and borehole electrodes in an area with significant topography
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