12,583 research outputs found

    Transfer function characteristics of super resolving systems

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    Signal quality in an optical storage device greatly depends on the optical system transfer function used to write and read data patterns. The problem is similar to analysis of scanning optical microscopes. Hopkins and Braat have analyzed write-once-read-many (WORM) optical data storage devices. Herein, transfer function analysis of magnetooptic (MO) data storage devices is discussed with respect to improving transfer-function characteristics. Several authors have described improving the transfer function as super resolution. However, none have thoroughly analyzed the MO optical system and effects of the medium. Both the optical system transfer function and effects of the medium of this development are discussed

    Moon-tracking orbits using motorized tethers for continuous earth–moon payload exchanges

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    For human colonization of the moon to become reality, an efficient and regular means of exchanging resources between the Earth and the moon must be established. One possibility is to pass and receive payloads at regular intervals between a symmetrically laden motorized momentum-exchange tether orbiting about Earth and a second orbiting about the moon. There are significant challenges associated with this method, among the greatest of which is the development of a system that incorporates the complex motion of the moon into its operational architecture in addition to conducting these exchanges on a per-lunar-orbit basis. One way of achieving this is to use a motorized tether orbiting Earth and tracking the nodes of the moon’s orbit to allow payload exchanges to be undertaken periodically with the arrival of the moon at either of these nodes. Tracking these nodes is achieved by arranging the tether to orbit Earth with a critical inclination, thus rendering its argument of perigee stationary in addition to using the precession effects resulting from an oblate Earth. Using this in conjunction with pre-emptive adjustments to its angle of right ascension, the tether will periodically realign itself with these nodes simultaneously with the arrival of the moon

    CONSUMER UNDERSTANDING AND USE OF HEALTH INFORMATION ON PRODUCT LABELS: MARKETING IMPLICATIONS FOR FUNCTIONAL FOOD

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    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,

    Gauge covariance and the fermion-photon vertex in three- and four- dimensional, massless quantum electrodynamics

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    In the quenched approximation, the gauge covariance properties of three vertex Ans\"{a}tze in the Schwinger-Dyson equation for the fermion self energy are analysed in three- and four- dimensional quantum electrodynamics. Based on the Cornwall-Jackiw-Tomboulis effective action, it is inferred that the spectral representation used for the vertex in the gauge technique cannot support dynamical chiral symmetry breaking. A criterion for establishing whether a given Ansatz can confer gauge covariance upon the Schwinger-Dyson equation is presented and the Curtis and Pennington Ansatz is shown to satisfy this constraint. We obtain an analytic solution of the Schwinger-Dyson equation for quenched, massless three-dimensional quantum electrodynamics for arbitrary values of the gauge parameter in the absence of dynamical chiral symmetry breaking.Comment: 17 pages, PHY-7143-TH-93, REVTE

    Narrow Line Cooling: Finite Photon Recoil Dynamics

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    We present an extensive study of the unique thermal and mechanical dynamics for narrow-line cooling on the 1S0 - 3P1 88Sr transition. For negative detuning, trap dynamics reveal a transition from the semiclassical regime to the photon-recoil-dominated quantum regime, yielding an absolute minima in the equilibrium temperature below the single-photon recoil limit. For positive detuning, the cloud divides into discrete momentum packets whose alignment mimics lattice points on a face-centered-cubic crystal. This novel behavior arises from velocity selection and "positive feedback" acceleration due to a finite number of photon recoils. Cooling is achieved with blue-detuned light around a velocity where gravity balances the radiative force.Comment: 4 pages, 3 figures, Phys. Rev. Lett., in pres

    Impact of grinding wheel specification on surface integrity and residual stress when grinding Inconel 718

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    The grinding process is often maligned by grinding burn; which refers to many unwanted effects, including residual stress formation. This paper presents an overview of the role of grinding wheel technologies in the surface response and residual stress formation of thin section Inconel 718. Using production standard equipment, conventional abrasive vitrified, and super abrasive electroplated wheel technologies were evaluated in initial comparative trials. Results revealed the dominant residual stress profiles, which manifested as measurable distortion and the thermo-mechanical impact of grinding, such as softening. Following this, a parametric study was carried out using cubic boron nitride super abrasive electroplated wheels to investigate the interaction of grinding parameters on the generated output. It was shown that at increased grinding aggressions, tensile stress regimes increased resulting in increased distortion magnitudes. The study highlights the importance of assessing residual stress formation when manipulating both wheel technologies and grinding parameters. It is envisaged that with additional assessment, a route to an engineered residual stress profile might be achieved

    Prevalence of working smoke alarms in local authority inner city housing: randomised controlled trial

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    Objectives To identify which type of smoke alarm is most likely to remain working in local authority inner city housing, and to identify an alarm tolerated in households with smokers. Design Randomised controlled trial. Setting Two local authority housing estates in inner London. Participants 2145 households. Intervention Installation of one of five types of smoke alarm (ionisation sensor with a zinc battery; ionisation sensor with a zinc battery and pause button; ionisation sensor with a lithium battery and pause button; optical sensor with a lithium battery; or optical sensor with a zinc battery). Main outcome measure Percentage of homes with any working alarm and percentage in which the alarm installed for this study was working after 15 months. Results 54.4% (1166/2145) of all households and 45.9% (465/1012) of households occupied by smokers had a working smoke alarm. Ionisation sensor, lithium battery, and there being a smoker in the household were independently associated with whether an alarm was working (adjusted odds ratios 2.24 (95% confidence interval 1.75 to 2.87), 2.20 (1.77 to 2.75), and 0.62 (0.52 to 0.74)). The most common reasons for non-function were missing battery (19%), missing alarm (17%), and battery disconnected (4%). Conclusions Nearly half of the alarms installed were not working when tested 15 months later. Type of alarm and power source are important determinants of whether a household had a working alarm

    Effect of dislocations on properties of heteroepitaxial InP solar cells

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    The apparently unrelated phenomena of temperature dependency, carrier removal and photoluminescence are shown to be affected by the high dislocation densities present in heteroepitaxial InP solar cells. Using homoepitaxial InP cells as a baseline, it is found that the relatively high dislocation densities present in heteroepitaxial InP/GaAs cells lead to increased volumes of dVoc/dt and carrier removal rate and substantial decreases in photoluminescence spectral intensities. With respect to dVoc/dt, the observed effect is attributed to the tendency of dislocations to reduce Voc. Although the basic cause for the observed increase in carrier removal rate is unclear, it is speculated that the decreased photoluminescence intensity is attributable to defect levels introduced by dislocations in the heteroepitaxial cells

    Meat buying and use in the Missouri restaurants

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    Digitized 2007 AES.Includes bibliographical references
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