Video signal processing system uses gated current mode switches to perform high speed multiplication and digital-to-analog conversion

Video signal processor uses special-purpose integrated circuits with nonsaturating current mode switching to accept texture and color information from a digital computer in a visual spaceflight simulator and to combine these, for display on color CRT with analog information concerning fading

Faint, moving objects in the Hubble Deep Field: components of the dark halo?

The deepest optical image of the sky, the Hubble Deep Field (HDF), obtained with the Hubble Space Telescope (HST) in December 1995, has been compared to a similar image taken in December 1997. Two very faint, blue, isolated and unresolved objects are found to display a substantial apparent proper motion, 23+/-5 mas/yr and 26+/-5 mas/yr; a further three objects at the detection limit of the second epoch observations may also be moving. Galactic structure models predict a general absence of stars in the color-magnitude range in which these objects are found. However, these observations are consistent with recently-developed models of old white dwarfs with hydrogen atmospheres, whose color, contrary to previous expectations, has been shown to be blue. If these apparently moving objects are indeed old white dwarfs with hydrogen atmospheres and masses near 0.5 M_Sun, they have ages of approximately 12 Gyr, and a local mass density that is sufficient, within the large uncertainties arising from the small size of the sample, to account for the entire missing Galactic dynamical mass.Comment: 6 pages, using emulateapj, including 2 colour figures, accepted for publication in ApJ Letter

Unevenly-sampled signals: a general formalism of the Lomb-Scargle periodogram

The periodogram is a popular tool that tests whether a signal consists only of noise or if it also includes other components. The main issue of this method is to define a critical detection threshold that allows identification of a component other than noise, when a peak in the periodogram exceeds it. In the case of signals sampled on a regular time grid, determination of such a threshold is relatively simple. When the sampling is uneven, however, things are more complicated. The most popular solution in this case is to use the "Lomb-Scargle" periodogram, but this method can be used only when the noise is the realization of a zero-mean, white (i.e. flat-spectrum) random process. In this paper, we present a general formalism based on matrix algebra, which permits analysis of the statistical properties of a periodogram independently of the characteristics of noise (e.g. colored and/or non-stationary), as well as the characteristics of sampling.Comment: 10 pages, 11 figures, Astronomy and Astrophysics, in pres

Process evaluation of fruit and vegetables distribution interventions in school-based settings: A systematic review

Despite the importance of process evaluation in program evaluations, research has focused primarily on the effectiveness of fruit and vegetables (FVs) distribution interventions on children\u27s consumption, with little attention given to how these interventions achieve their outcomes. Five bibliographic databases (Embase, PubMed, ProQuest, Scopus, and Web of Science Core Collection) were searched in June 2019 for studies of interventions where the main focus was the implementation of distributed FVs to school-aged children as a snack. The Critical Appraisal Skills Programme (CASP) tool was used to appraise the risk of bias within included studies. Data were extracted based on study characteristics and findings. Results identified 24 studies reporting on 11 interventions and 1 policy. The findings of this systematic review indicate that the majority of the studies included limited references to implementation research. Recurring limitations include an absence of an evaluation theoretical framework and the data collection methods used. Also, several factors were identified as informing the success of snack-based FVs distribution programs, including participation of the school community, school characteristics, background knowledge, and parental engagement. Lack of timely FVs delivery, limited funding, inadequate awareness about the program, insufficient teachers’ time, and food waste were identified as challenges to successful programming. Findings indicate that distributing FVs to school-aged children as a snack can increase their consumption, but only with proper implementation. Further evaluative research is required to better inform future implementation of snack-based FV distribution interventions in school settings

Assessing the relationship between water and nutrition knowledge and beverage consumption habits in children

Objective: To examine the relationship between knowledge and beverage consumption habits among children. Design: Cross-sectional analysis. Linear regression was used to identify sociodemographic, dietary and behavioural determinants of beverage consumption and knowledge, and to describe the relationships between children’s knowledge and water and sugar-sweetened beverage (SSB) consumption. Settings: Seventeen elementary schools in London, Ontario, Canada. Participants: A total of 1049 children aged 8–14 years. Results: Knowledge scores were low overall. Children with higher knowledge scores consumed significantly fewer SSB (β = −0·33; 95 % CI −0·49, −0·18; P \u3c 0·0001) and significantly more water (β = 0·34; 95 % CI 0·16, 0·52; P = 0·0002). More frequent refillable water bottle use, lower junk food consumption, lower fruit and vegetable consumption, female sex, higher parental education, two-parent households and not participating in a milk programme were associated with a higher water consumption. Male sex, higher junk food consumption, single-parent households, lower parental education, participating in a milk programme, less frequent refillable water bottle use and permission to leave school grounds at lunchtime were associated with a higher SSB consumption. Water was the most frequently consumed beverage; however, 79 % of respondents reported consuming an SSB at least once daily and 50 % reported consuming an SSB three or more times daily. Conclusions: Elementary-school children have relatively low nutrition and water knowledge and consume high proportions of SSB. Higher knowledge is associated with increased water consumption and reduced SSB consumption. Interventions to increase knowledge may be effective at improving children’s beverage consumption habits

An economic impact comparative analysis of farmers’ markets in Michigan and Ontario

Farmers\u27 markets play a vital role in local economic development by providing a site for local and small business incubation, creating an economic multiplier effect to neighboring businesses, and recycling customer dollars within the community. While several studies have evaluated characteristics of farmers\u27 markets within single metropolitan areas, few have compared the impact of multiple markets in socioeconomically contrasting regions. This research compares shopping habits and economic impacts of customers at farmers\u27 markets in two North American cities: Flint, Michigan, and London, Ontario. Overall, 895 market visitors completed surveys. We conducted statistical and spatial analyses to identify differences between these markets. Though geographically proximate and similar in metropolitan size, the two cities differ greatly in recent economic development, social vitality, and public health indicators. The objectives of this article are to quantify the impact that each market has on its local economy and contextualize these impacts in light of the place-specific attributes of each market. Results indicate that customers come from a mix of urban and suburban locations, but that key urban areas do not draw a substantial share of customers. Marketing efforts in nearby disadvantaged neighborhoods, therefore, might yield new customers and increase multiplier effects within the neighborhoods. The London market drew slightly younger customers who shopped less frequently, while the Flint market drew an older crowd that attended more regularly. This may be attributable to the relative age of the markets, and certainly reflects the marketing push of each market\u27s managers. Given the opportunity to compare similarities and differences, much can be learned from each market in terms of opportunities for marketing, local economic development, and increased community vitality