Use of satellite data in agricultural surveys

A major application of satellite remote sensing is the estimation of the acreage of agricultural crops. The potential for crop yield estimation using satellite remote sensing exists, but research in this area is still in its early stages. In this paper we survey the methodology for using remotely sensed data in agricultural surveys, based primarily on research conducted during the Large Area Crop Inventory Experiment (LACIE) and the follow-on program Agricultural Research and Inventory Surveys Through Aerospace Remote Sensing (AgRISTARS). The data obtained from multispectral scanner (MSS) and thematic mapper (TM) sensors onboard the Landsat series of satellites are described. Approaches for preprocessing, transferring, and modeling these data for understanding the relationship between their temporal behavior and crop growth cycles are discussed. Finally, techniques for crop identification and area and yield estimation are briefly described     

"Walking the Walk" of Public Service Motivation: Public Employees and Charitable Gifts of Time, Blood, and Money

Research generally indicates that public employees "talk thetalk," but do they also "walk the walk" of the public servicemotive (PSM)? Are public service employees more likely thanothers to engage in public service activities? The behavioralimplications of PSM are addressed by studying the involvementin charitable activities of public, nonprofit, and private workers.Using data from the 2002 General Social Survey, multivariatelogistic regression models are estimated to examine self-reportedgifts of time, blood, and money to charitable organizations.It is found that government employees are more likely to volunteerfor charity and to donate blood than for-profit employees are.Additionally, nonprofit workers are also more likely than theirfor-profit counterparts to volunteer. However, no differenceis found among public service and private employees in termsof individual philanthropy. These findings generally lend supportfor the hypothesis that PSM is more prominent in public servicethan in private organizations, especially as it pertains togovernment personnel.     

Sampling Weights for Analyses of Couple Data: Example of the Demographic and Health Surveys

In some surveys, women and men are interviewed separately in selected households, allowing matching of partner information and analyses of couples. Although individual sampling weights exist for men and women, sampling weights specific for couples are rarely derived. We present a method of estimating appropriate weights for couples that extends methods currently used in the Demographic and Health Surveys (DHS) for individual weights. To see how results vary, we analyze 1912 estimates (means; proportions; linear regression; and simple and multinomial logistic regression coefficients, and their standard errors) with couple data in each of 11 DHS surveys in which the couple weight could be derived. We used two measures of bias: absolute percentage difference from the value estimated with the couple weight and ratio of the absolute difference to the standard error using the couple weight. The latter shows greater bias for means and proportions, whereas the former and a combination of both measures show greater bias for regression coefficients. Comparing results using couple weights with published results using women’s weights for a logistic regression of couple contraceptive use in Turkey, we found that 6 of 27 coefficients had a bias above 5 %. On the other hand, a simulation of varying response rates (27 simulations) showed that median percentage bias in a logistic regression was less than 3 % for 17 of 18 coefficients. Two proxy couple weights that can be calculated in all DHS surveys perform considerably better than either male or female weights. We recommend that a couple weight be calculated and made available with couple data from such surveys.     

Parental Linguistic Input and Its Relation to Toddlers’ Visual Attention in Joint Object Play: A Comparison Between Children with Normal Hearing and Children With Hearing Loss

Parent–child interactions are multimodal, often involving coordinated exchanges of visual and auditory information between the two partners. The current work focuses on the effect of children's hearing loss on parent–child interactions when parents and their toddlers jointly played with a set of toy objects. We compared the linguistic input received by toddlers with hearing loss (HL) and their chronological age‐matched (CA) and hearing age‐matched (HA) normal‐hearing peers. Moreover, we used head‐mounted eye trackers to examine how different parental linguistic input affected children's visual attention on objects when parents either led or followed children's attention during joint object play. Overall, parents of children with HL provided comparable amount of linguistic input as parents of the two normal‐hearing groups. However, the types of linguistic input produced by parents of children with HL were similar to the CA group in some ways and similar to the HA group in other ways. Interestingly, the effects of different types of linguistic input on extending the attention of children with HL qualitatively resembled the patterns seen in the CA group, even though the effects were less pronounced in the HL group. We discuss the implications of these results for our understanding of the reciprocal, dynamic, and multi‐factored nature of parent–child interactions.     

Knowledge and Beliefs About Gambling in Australian Secondary School Students and their Implications for Education Strategies

This study investigated the nature of gambling-related knowledge and beliefs in a survey study of 2,669 students aged 13–17 years in South Australia. Students were classified as pathological gamblers, at risk, or not at risk based upon the DSM-IV-J, and their responses to questions relating to objective odds, probabilities, and common misperceptions were compared. The study confirmed previous studies which have shown that pathological gamblers are more susceptible to erroneous beliefs concerning randomness and chance, but do not differ in terms of their knowledge of objective odds. These findings were discussed in terms of Ladouceur’s notion of “cognitive switching” and the distinction drawn between “hot” and “cold” cognitions in clinical outcome studies. The implications for school-based education programs are examined with attention given to the potential value of role-playing and simulations in encouraging student reflection and self-awareness.     

Birth-interval dynamics in rural Bangladesh and maternal weight

This article reports on the results of a study conducted in rural Bangladesh on the influence of maternal weight on the components of birth intervals, including gestation and intrauterine mortality, the duration of postpartum amenorrhea, and the duration of waiting time to conception (the menstrual interval). When biological factors (including maternal age, parity, and supplementation practices) and behavioral variables, including religion, education, and occupation, were controlled, maternal weight was found to be related to the risk of intrauterine mortality and to the probability of resuming menses in the postpartum period. The implications of these findings for policies and programs in developing countries are discussed.