Guide Star Research Articles

The effect of health prompts on product consideration, attention to information, and choice in large, online product assortments: The case of fiber

Health-focused point-of-decision prompts (PDPs) influence consumers to purchase healthier food products, but how PDPs work has not been established. We examined how a PDP focused on fiber consumption, an under-consumed nutrient, influences consumers to select healthier products. US-based participants (n = 753), randomly assigned to a PDP or control condition, completed a simulated online shopping experience that included features of real-world retail settings, such as the ability to examine subsets of products and to choose to access nutrition information. In each condition, participants made choices in cereal, bread, and cracker categories. Participants could choose to view all or subsets of products before making a selection and reported the nutrient information they examined. We used mediation analysis to examine direct and indirect pathways through which the PDP affected the fiber content and healthiness rating of choices. Indirect pathways were whether the set of products the participant considered included healthy options (HCS) and attention to fiber information (AFI) when making choices. The PDP increased fiber content and Guiding Stars (GS) ratings of product choices by a total of 0.53 g dietary fiber/serving and 0.25 GS, respectively. This increase resulted from direct and indirect influences from the PDP. The direct effect increased fiber (GS) by 0.19 g dietary fiber/serving (0.072 GS). The indirect influence of the PDP through HCS increased 0.21 g dietary fiber/serving (0.104 GS) and through AFI increased 0.13 g dietary fiber/serving (0.035 GS). The PDP engendered healthier purchases by influencing consumer behavior at multiple points in the decision-making process.

Educational Campaigns for Product Labels: Evidence from On-Shelf Nutritional Labeling

Front-of-package and on-shelf nutrition labeling systems in supermarkets have been shown to lead to only modest increases in the purchase of more nutritious foods. Educational campaigns may increase the use of these types of product labels if (1) there is a lack of consumer awareness and/or understanding of the labels, and (2) the information provided leads consumers to prefer different products. The authors study a large-scale national campaign for the Guiding Stars nutrition labels conducted by a grocery retailer in Canada that implemented the labels. Using detailed household transaction data, the authors find only a small increase in the purchase of higher star–rated foods during the campaign, driven by produce purchases, and 60% of the effect disappears after the campaign’s conclusion. Exit surveys were conducted outside of stores before and after the campaign to explain the limited response. Awareness and understanding of the nutrition labeling system increased marginally after the campaign, but there was no increase in self-reported use.

Simulation Study of on Sky Performance of a New 20W Class Macro–Micro Pulse Laser for Sodium Laser Guide Star

As one crucial component for the latest generation of adaptive optics, tremendous efforts have been put into the development of high performance 20 W class sodium laser guide star laser system. Two such systems, the continuous wave laser by Toptica, and the quasi-continuous pulse laser by TIPC were extensively studied with simulation and field tests. A new type of 20 W class sodium laser, macro–micro pulse laser, is currently being developed by CIOMP. In this paper, we will study its on-sky performance with simulation based on Monte Carlo rate equation method. The predicted coupling efficiency for this laser in the zenith direction in Changchun is 179.73 photons s−1 W−1/(atoms m−2). The variation of coupling efficiency of this type of laser with pointing direction and the effect of D2b repumping are also studied and reported in this paper.

The Guiding Star: The Journey of an International Physician From Maternal Fetal Medicine to Fetal Neonatal Neurology.

My path to the American dream took me from maternal fetal medicine in India to fetal and neonatal neurology in the United States, a journey spanning 2 continents, 3 countries, 3 healthcare systems, 4 rounds of the residency match process, 2 residency trainings and 4 fellowships. Through it all I had the good fortune to be guided by a wonderful support system of mentors, family, and friends. This is my story of how and why.

Nutritional quality of retail food purchases is not associated with participation in the Supplemental Nutrition Assistance Program for nutrition-oriented households.

The Supplemental Nutrition Assistance Program (SNAP) provides millions of low-income Americans food benefits and other forms of nutrition assistance. Evidence indicates that SNAP reduces food insecurity. However, there is a concern that the food benefit may increase the demand for less healthy foods more than healthier foods, thereby reducing the overall nutritional quality of the participant's food basket. This paper aims to examine the association of SNAP participation with the nutritional quality of food-at-home purchases of low-income households and to investigate the potential heterogeneity among consumers with different levels of nutrition attitude. This analysis used food purchase data from the USDA National Household Food Acquisition and Purchase Survey (FoodAPS). Our study sample included 2,218 low-income households, of which 1,184 are SNAP participants, and 1,034 are income-eligible nonparticipants. Multivariate regressions were performed to explore the SNAP-nutritional quality association. A household's nutrition attitude was measured using its response to a question on whether the household searched for nutrition information online in the last 2 months. Households that affirmed they had an online nutrition search were treated as nutrition-oriented households (21.2% of the low-income sample), and households that did not were considered less nutrition-oriented households (78.8%). For robustness, we also created an alternative nutrition attitude measure based on reported use of the nutrition facts label. We found that among less nutrition-oriented households, SNAP participants had a statistically significant 0.097 points (p = 0.018) lower Guiding Stars rating than low-income nonparticipants. However, there was no significant SNAP-nutritional quality association among nutrition-oriented households. In conclusion, SNAP participation was associated with lower nutritional quality of food purchases among less nutrition-oriented households, but not among nutrition-oriented households. The results suggest that the intended nutritional benefits of restrictions on purchases of healthy foods may not reach the subgroup of nutrition-oriented SNAP participants.

Preliminary design of the MAORY Calibration Unit

MAORY (Multi-conjugate Adaptive Optics RelaY) is one of the first light instruments for the ESO Extremely Large Telescope (ELT). It will be firstly used by MICADO (Multi-AO Imaging CamerA for Deep Observations), a near-infrared high-angular resolution imager, to compensate aberrations and provide high-Strehl images within a (53” × 53”) Field of View (FoV). The complexity of MAORY requires calibration functionalities for both the AIV (Assembly-Integration-Verification) and the operational phase. The function of the Calibration Unit (CU) is keeping the high efficiency of the adaptive correction provided by MAORY during the operational phase, through proper calibration sources, acting as both Natural Guide Stars (NGS) and Laser Guide Stars (LGS) sources. An overview of the system, the status of the current design and the main challenges to face in the future are presented in this work.

Does how you pay influence the share of healthy items that you Buy? Assessing differences in nutritional quality of food purchases by payment type

Shoppers that use cash as a form of payment are more likely to evaluate the necessity of an item they purchase than shoppers that pay with other forms of payment, such as credit cards. In this paper, we hypothesize that the use of cash may nudge shoppers to buy more healthful food items. We empirically evaluate whether the payment method affects the nutritional quality of food purchases. We also test whether the effect of payment type differs between food-at-home and food-away-from-home events. Specifically, we test whether shoppers purchase a higher share of nutritious food items when they pay with cash compared to when they use credit and debit cards. We use the National Household Food Acquisition and Purchase Survey (FoodAPS) data that tracks individual’s food purchases over one week. Using the Guiding Stars Program (GSP) algorithm to measure the nutritional quality of food items, we calculate the share of healthy items purchased at each event. We find that shoppers using cash purchase a higher share of healthy items than when they use credit or debit cards, and this nudging effect is primarily driven by food-away-from-home purchases.

Uplink wavefront corrector system: from paper to reality.

The Uplink Wavefront Corrector System (UWCS) is a pathfinder instrument to demonstrate the uplink correction by Adaptive Optics techniques; this novel application can be directly usable in two fields: Free-Space Optical Communications and the generation of Laser Guide Stars. A Rayleigh LGS is propagated to the sky while the atmospheric wavefront aberrations are measured by a Shack-Hartmann WFS with 12 x 12 sub-apertures using a Natural Guide Star as a reference. The laser upwards propagation path is then pre-compensated by a 97-actuator deformable mirror. A scoring camera is attached to the finder telescope, next to the main aperture, in order to show the overall result, which is assessed in terms of beam power concentration. Present paper described the design process of the UWCS and its integration and testing in the Optical Ground Station telescope, at Teide Observatory (Spain).

Angiographic Imaging of an In Vivo Mouse Brain as a Guiding Star for Automatic Digital Refocusing in OCT

A method allows the extraction of the recovery factor that maximizes the image contrast of OCT (optical coherence tomography) and/or OCTA (OCT angiography) of a living subject is proposed in this study. Due to the finite depth of focus in imaging optics, the volume OCT imaging suffers from blurriness in the lateral resolution. By utilizing the digital hologram method or angular spectrum method, the blurred image can be refocused. However, for in vivo OCT imaging, evaluation of the image focus is not easy, owing to the cloudy structure of the brain. In the proposed method, the blood flow signals were used as a guiding star to find the recovery factor. The propagation distance to a focal plane was automatically determined by evaluating the contrast of a cross-sectional OCTA image. The performance was examined though in vivo mouse brain OCT/OCTA imaging. The image singularity of the blood flow in OCTA was very effective at evaluating the contrast of the image.

Optimization of guide star catalog for daytime star sensors

Daytime star sensor provides accuracy navigation information to air vehicles near the ground in the daytime by observing stars. It has been an important development of modern star sensors. In order to achieve a high signal-to-noise ratio, daytime star sensors work in the infrared band to avoid interferences from sky background. Daytime star sensors output accurate attitudes by identifying the observed stars in the field of view (FOV) according to the loaded guide star catalog. Guide stars are usually required to be distributed uniformly on the celestial sphere to improve the performance of star pattern identification. The parameters including limiting magnitude and FOV are determined by processing the 2MASS star catalog as the original star data and performing star distribution statistics. After constellation features are discussed, the idea of distributing stars in the local FOV to constellations is put forward by using the star pair angular separations. An optimization algorithm to build the guide star catalog for daytime stars is proposed to achieve evenly distributed guide stars. The guide star catalog is established and analyzed, proving that the proposed algorithm has simple calculation and easy realization. The Boltzmann entropy of obtained guide star catalog drops two orders of magnitude. Guide stars are distributed more uniformly.

Keck/OSIRIS IFU Detection of a z ∼ 3 Damped Lyα Host Galaxy∗

Abstract We present Keck/OSIRIS infrared IFU observations of the z = 3.153 sub-DLA DLA2233+131, previously detected in absorption to a background quasar and studied with single-slit spectroscopy and Potsdam Multi Aperture Spectrophotometer integral field spectroscopy (IFU). We used the Laser Guide Star Adaptive Optics and OSIRIS IFU to reduce the point-spread function of the background quasar to FWHM ∼ 0.″15 and marginally resolve extended, foreground DLA emission. We detect emission with a flux erg s−1 cm−2, as well as unresolved and Hβλ4861 emission. Using a composite spectrum over the emission region, we measure dynamical mass M ⊙. We made several estimates of star formation rate (SFR) using and Hβλ4861 emission, and measured a SFR of ∼7.1 − 13.6 M ⊙ yr−1. We map and Hβλ4861 emission and the corresponding velocity fields to search for signs of kinematic structure. These maps allow for a more detailed kinematic analysis than previously possible for this galaxy. While some regions show slightly red and blueshifted emission indicative of potential edge-on disk rotation, the data are insufficient to support this interpretation.

Design and development of an adaptive optics system in visible and near-infrared for Inter-University Centre for Astronomy and Astrophysics 2-meter telescope

Robo-AO is the first robotic autonomous laser-guided adaptive optics (AO) system operating in the sky. It is a very economical AO system especially suitable for observations with 1- to 3-m class telescopes. A second Robo-AO system, which works both in the visible and near-infrared wavelengths, has been developed to improve the image quality of the 2-m diameter telescope at Inter-university Centre for Astronomy and Astrophysics Girawali Observatory in India. We present the optomechanical design and development of the Laser Guide Star Facility (LGSF) and the Cassegrain AO facility with various test results. Effects of different projection geometries of the LGSF have been discussed with modeling results. Comprehensive study of an atmospheric dispersion corrector with dispersion model and development of a generic software are elaborated with experimental results. Toward the end, AO loop test results in the presence of artificial turbulence generated in the laboratory are presented.

Characteristics study and robustness comparison of various star pattern recognition algorithm for star sensor using digital simulation

The last few years the use of star sensor, which is the most accurate sensor on satellites, began to penetrate into micro satellites and nano satellites, previously used only on high-end satellites. Hence we need to develop star sensor according to the specific needs of microsatellite and nano satellites. One of star sensor’s aspect is star pattern recognition algorithm. A good star pattern recognition algorithm must have a high level of matching success when there are a lot of disturbances (robust) and fast processing time. There are different types of star pattern recognition algorithms, which have their respective advantages and disadvantages, so it is necessary to characterize and compare the various algorithms. In this paper, the characterization and comparison of robustness in different types of star pattern recognition algorithm are done using digital simulation. The simulation results show that the success rate does not always rise with the number of stars used for matching because it depends on how the algorithm works. In addition, the more the number of stars are used, the longer processing time, and vice versa. The best algorithm in terms of success rate is an algorithm that uses a combination pattern of all possible triangles, in other words most robust, but has the longest processing time. This long processing time can be overcome by optimizing GSC (Guide Star Catalogue). From the results the multitriangles 2 algorithm has the best success rate compared to the other algorithms, with success rate for 5, 6, and 7 stars configuration are 97.8%, 98.7%, and 99.8% respectively.

Guide Star Selection for the Three-FOV Daytime Star Sensor.

To realize the application of the star sensor in the all-day carrier platform, a three-field-of-view (three-FOV) star sensor in short-wave infrared (SWIR) band is considered. This new prototype employs new techniques that can improve the detection capability of the star sensor, when the huge size of star identification feature database becomes a big obstacle. Hence, a way to thin the guide star catalog for three-FOV daytime star sensor is studied. Firstly, an introduction of three-FOV star sensor and an example of three-FOV daytime star sensor with narrow FOV are presented. According to this model and the requirement of triangular star identification method, two constraints based on the number and the brightness of the stars in FOV are put forward for guide star selection. Then on the basis of these constraints, the improved spherical spiral method (ISSM) is proposed and the optimal number of reference points of ISSM is discussed. Finally, to demonstrate the performance of the ISSM, guide star catalogs are generated by ISSM, magnitude filter method (MFM), 1st order self-organizing guide star selection method (1st-SOPM) and the spherical spiral method (SSM), respectively. The results show that the guide star catalog generated by ISSM has the smallest size and the number and brightness characteristics of its guide stars are better than the other methods. ISSM is effective for the guide star selection in the three-FOV daytime star sensor.

Research and Development for Atmospheric Turbulence Compensation with Laser Guide Star

Adaptive optics in astronomy has opened a new era especially for a ground-based 8 to 10 m telescopes. The effect of atmospheric turbulence is no longer restriction to achieve a diffraction limited spatial resolution for large telescopes. Stellar image size has been improved by a factor of more than 10. Further, laser guide star adaptive optics expands the possibility to observe the sky area, where no bright star can be found as a reference source of measuring a wavefront. This article introduces a basic concept of laser guide star adaptive optics, laser system and a system components to create a laser beacon, hybrid control system of laser guide star adaptive optics with tip-tilt and focus natural guide stars, laser safety operation to protect aircrafts and satellites, as well as to avoid a contamination to the adjacent telescopes.

Novel guide star optimal selection algorithm for star sensors based on star clustering

Modern space vehicles face the challenges to obtain more and more accurate attitudes in order to complete the demanding tasks. Onboard star sensors which identify the observed stars in the field of view according to the loaded guide star catalog and output accurate attitude have attracted most interests. Guide stars are usually required to distribute uniformly on the celestial sphere to improve the performance of the star pattern identification. An optimal selection algorithm is proposed to achieve an even distribution of guide stars in this paper. Constellation features are discussed. The mean shift algorithm is analyzed. The idea that distributes stars in the local field of view to constellations is proposed by using the star pair angular separations according to the star positions in the inertial coordinate system. The optimal selection algorithm of guide stars based on star clustering is developed. Its detailed implement procedures are introduced completely. The guide star optimal selection experiment in visible band by using SAO star catalog as the original star data is implemented. It proves that the proposed algorithm has the virtue of simple calculation and easy realization. The obtained guide star distribution is superior to the regression selection algorithm and the magnitude weighted method.

Guide star based deconvolution for imaging behind turbid media

BackgroundIf structures of interest are hidden beneath turbid layers such as biological tissues, imaging becomes challenging, even impossible. However, if the point spread function of the system is known from the presence of a guide star, application of common deconvolution algorithms can be a convenient approach to reconstruct even heavily scrambled images. In this work, we present the severity of scattering and the capability of deconvolution techniques in optical settings realistically mimicking biological applications.MethodsWe determine the point spread function (PSF) of the optical path using a single fluorescent bead hidden behind a scattering layer. Once the PSF is obtained, a scene containing several beads is brought to the exact the same position behind the scattering layer. The scrambled image of the scene is then deconvoluted with the PSF. Plastic films and thin slices of chicken tissues are used as scattering layers.ResultsDespite the low signal provided by small fluorescent particles and their short distance of a few millimeters to the turbid media, the reconstructed images reproduced the original scenes successfully. The spatial variance of the PSF caused by the inhomogeneous scattering layer mainly limited the size of the reconstructed area.ConclusionOur method overcomes the negative effects of scattering on the detection side of an imaging system. However, it can be combined with wavefront shaping methods optimizing the illumination path as well leading to even further increase of signal to noise ratio and image quality. The required guide star can be brought inside the biological sample to a desired position using optical fibers as a light guide or using capillaries filled with bright fluorescent molecules.

Raman-scattered laser guide-star photons to monitor the scatter of astronomical telescope mirrors

The first observations of laser guide-star photons that are Raman-scattered by air molecules above the Very Large Telescope (VLT) were reported in June 2017. The initial detection came from the Multi-Unit Spectroscopic Explorer (MUSE) optical integral field spectrograph, following the installation of the 4 Laser Guide Star Facility (4LGSF) on Unit Telescope 4 (UT4) of the VLT. In this Letter, we delve further into the symbiotic relationship between the 4LGSF laser guide-star system, the UT4 telescope, and MUSE by monitoring the spectral contamination of MUSE observations by Raman photons over a 27-month period. This dataset reveals that dust particles deposited on the primary and tertiary mirrors of UT4, which are responsible for a reflectivity loss of ∼8% at 6000 Å, contribute (60 ± 5)% to the laser line fluxes detected by MUSE. The flux of Raman lines, which contaminates scientific observations that are acquired with optical spectrographs, thus provides a new, non-invasive means to monitor the evolving scatter properties of the mirrors of astronomical telescopes that are equipped with laser guide-star systems.

Impact of Laser Guide Star facilities on neighbouring telescopes: the case of GTC, TMT, VLT, and ELT lasers and the Cherenkov Telescope Array

Powerful Laser Guide Star (LGS) systems are standard for the next-generation of extremely large telescopes. However, modern earth-based astronomy has gone through a process of concentration on few sites with exceptional sky quality, resulting in those becoming more and more crowded. The future LGS systems encounter hence an environment of surrounding astronomical installations, some of which observing with large fields-of-view. We derive formulae to calculate the impact of LGS light on the camera of a neighbouring telescope and the probabilities for a laser crossing the camera field-of-view to occur, and apply these to the specific case of the next very-high-energy gamma-ray observatory "Cherenkov Telescope Array" (CTA). Its southern part shall be constructed in a valley of the Cerro Armazones, Chile, close to the "Very Large Telescope" (VLT) and the "European Extremely Large Telescope" (ELT), while its northern part will be located at the "Observatorio del Roque de los Muchachos", on the Canary Island of La Palma, which also hosts the "Gran Telescopio de Canarias" (GTC) and serves as an optional site for the "Thirty Meter Telescope" (TMT), both employing LGS systems. Although finding the artificial star in the field-of-view of a CTA telescope will not disturb observations considerably, the laser beam crossing the field-of-view of a CTA telescope may be critical. We find no conflict expected for the ELT lasers, however, 1% (3%) of extra-galactic and 1% (5%) of galactic observations with the CTA may be affected by the GTC (TMT) LGS lasers, unless an enhanced version of a laser tracking control system gets implemented.

Consumer responses to private nutrition signals

ABSTRACTMandatory labelling of nutrition information with a numerical nutrition facts panel is commonly required for prepackaged food products. Recently, food manufacturers and retailers have developed simplified nutrition signals such as front-of-package labelling (e.g. the Traffic Light label) or retail shelf labels (e.g. Guiding Stars), which provide a more intuitive signal of nutritional content. Using survey data from a sample of consumers from western Canada, this paper examines consumer responses to two private nutrition labelling programs: Guiding Stars and the Traffic Light label. Consumers are more receptive to the Traffic Light label than the Guiding Stars. Ordered probit models explore the factors influencing the likelihood of using these nutrition signals. Trust in the food label, perceived difficulty of using nutrition information, nutrition knowledge, and the importance placed on nutrition influence receptively to these labels. Simplified nutrition labels are likely to complement, rather than substitute for, the existing Nutrition Facts Table.