断夜处理天数对延迟甘蔗开花的影响

对早花甘蔗亲本进行同一光照强度不同持续天数的断夜处理,研究断夜天数对甘蔗开花的影响和不同品系对断夜天数反应的差异.参试品种在8月下旬至9月中旬间断夜15天和26天处理的开花高峰期分别比自然光照处理的延迟20天和30天左右,增加断夜天数对推迟甘蔗始花期和降低抽穗率有明显的影响,但不同品系对断夜天数的反应,特别是在开花持续期和终花期方面,存在较大的差异.在实际应用中,宜根据不同品系的特性确定适宜的断夜处理天数.     

Young people’s digital lives: The impact of interpersonal relationships and digital media use on adolescents’ sense of identity

The current study investigates the joint effects of interpersonal relationships and digital media use on adolescents’ sense of identity. Questionnaires were administered to a sample of 2079 students (57% female) between the ages of 11 and 19 years (M = 15.4 years) attending one of seven secondary schools in Bermuda. Using structural equation modeling, the author found that mothers and friends play an important role in adolescents’ lives, with both relationships contributing in positive ways to respondents’ self-concept clarity. Further, the results showed that mother relationship quality affected adolescents’ self-concept clarity both directly and indirectly, through the positive impact it had on friendship quality. Friends also played a mediating role in relation to aspects of adolescents’ digital media use. Specifically, the negative association detected between online identity expression/exploration and self-concept clarity was mediated partially by low friendship quality. Going online to communicate with one’s friends appeared to play a more positive role in adolescents’ sense of identity. The results showed that online peer communication affected self-concept clarity indirectly through its positive impact on friendship quality.     

Managing children's risk of injury in the home: Does parental teaching about home safety reduce young children's hazard interactions?

Past research confirms that parents extend much effort to teach their young children about safety, but little is known about this process. The present study examined mothers’ use of teaching as a strategy to manage young children's risk of home injury and how this impacts children's hazard interactions. Mothers of three-year-olds completed an in-home room-by-room interview in which they identified injury hazards that concern them, reported on use of teaching to manage risk of injury from these hazards, rated children's understanding of these safety issues and compliance with behavioral guidelines regarding these safety issues, and reported on children's recent interactions with these hazards. They also completed questionnaire measures of how difficult the child is to manage and the child's typical level of risk taking. Results revealed that children's understanding of safety impacted both their compliance and hazard interactions, moderating the impact of risk taking on compliance and also the impact of children's difficult-to-manage score on hazard interactions. These findings demonstrate that teaching strategies need to effectively enhance children's understanding of the safety issue in order to reduce children's risk of hazard interactions.     

Preschoolers' perceptions of their mothers' and fathers' reactions to injury-risk behavior

Seventy-eight 3 year-old children participated in structured interviews. Boys reported wanting to engage in higher levels of risk than did girls. Children viewed mothers as allowing boys and girls to engage in similar levels of risk. Conversely, they viewed fathers as permitting higher levels of risk by boys than by girls. These findings are discussed in terms of family socialization.     

Teaching children about bicycle safety: An evaluation of the New Jersey Bike School program

There are multiple health and environmental benefits associated with increasing bicycling among children. However, the use of bicycles is also associated with severe injuries and fatalities. In order to reduce bicycle crashes, a bicycling education program was implemented in selected New Jersey schools and summer camps as part of the New Jersey Safe Routes to School Program. Using a convenience sample of participants to the program, an opportunistic study was designed to evaluate the effectiveness of two bicycle education programs, the first a more-structured program delivered in a school setting, with no on-road component, and the other a less structured program delivered in a summer camp setting that included an on-road component. Tests administered before and after training were designed to assess knowledge acquired during the training. Questions assessed children's existing knowledge of helmet use and other equipment, bicycle safety, as well as their ability to discriminate hazards and understand rules of the road. Participating children (n = 699) also completed a travel survey that assessed their bicycling behavior and their perception of safety issues. Response to individual questions, overall pre- and post-training test scores, and changes in test scores were compared using comparison of proportion, t-tests, and ordinary least-squares (OLS) regression. Improvements between the pre-training and post-training test are apparent from the frequency distribution of test results and from t-tests. Both summer camps and school-based programs recorded similar improvements in test results. Children who bicycled with their parents scored higher on the pre-training test but did not improve as much on the post-training test. Without evaluating long-term changes in behavior, it is difficult to ascertain how successful the program is on eventual behavioral and safety outcomes.     

Parents’ living conditions influence offspring fitness and competency

In this study, we used Callosobruchus maculatus as a model insect to assess the idea of whether or not environmental conditions experienced by parents subsequently moderate offspring fitness and competency. We observed that parents’ experiences (sex ratio of parents, restricted access to mates, and honey access) influenced their offspring’s features and did not significantly affect traits such as offspring sex ratio, larval duration, and longevity. However, not only offspring (F1) but also grand-offspring (F2) copulation behaviors, egg number, and hatching percentage were influenced by parents’ experiences. Hence, the offspring of parents living in unfavorable conditions had higher copulation success, higher male mating propensity, and a lower mating latency time in adulthood than the progeny of parents kept under natural or favorable conditions. Interestingly, the offspring of parents with favorable living conditions showed the least tendency to copulate immediately. Even grandparents’ experience could affect descendant behaviors and shorten copulation duration. Adjustments of the parents to their environment were inherited by offspring and grand-offspring to cope better with challenging circumstances and might make the organism more competent. Therefore, the parents’ living conditions have a remarkable impact on how their progeny behave in different situations.     

Evaluating a model linking assessed parent factors to four domains of youth risky driving

Motor vehicle collisions are the leading cause of death in youth aged 15–19. Research has consistently shown that driver education programs do not result in safer youth driving. Indeed, the biggest predictor of collisions involving youth is parental history of collisions. The current study examined how parental modeling of and teaching about risky driving behaviors related to youth practices within four domains of risky driving (aggressive, substance use, distracted, moving violations), and evaluated whether the Prototype-Willingness Model explains links from parent to teen driving practices. Participants (N = 432) were undergraduate students (mean age 18 years, age range 17–22 years) who had obtained their G2 driver's license within the past year; the G2 driver's license allows youth to drive alone on all municipal roads, with some restrictions on their blood alcohol level and the number of passengers they can carry. Results revealed that parental modeling was more predictive than parental teaching for all domains of risky driving examined. Youth whose parents modeled risky driving behaviors were found to be more likely to have engaged in those risky driving behaviors in the past, as well as to be more willing to engage in the behaviors in the future. The Prototype-Willingness Model was not a good fit to explain these relations. Findings from this study highlight the role parents play in the development of youth risky driving practices.     

Parent comments and instruction during the first four months of supervised driving: An opportunity missed?

The present study examined the nature of the comments and instruction provided by parents during supervised driving. Unlike previous studies which rely on self-report, the data in this study were obtained through direct observation of parents and teens using in-vehicle cameras with audio recording. The cameras were installed in the vehicles of 50 families for the first four months of the learner license stage. The findings show a great deal of conversation takes place while teens are driving with a supervisor, and that much of this conversation concerns driving. Sixty-one percent (61%) of all recorded clips included driving-related conversation. The most common type of comment by parents was instruction about vehicle handling or operation, observed in 53% of those clips with conversation about driving. This was followed by pointing out something about the driving environment (such as when it was clear to enter traffic; 23%), negative comments about the teen's driving (22%), and helping the driver navigate (18%). Other potentially helpful types of instruction, including explanation or insights regarding higher order skills (e.g., hazard anticipation and detection), were noticeably less frequent. Moreover, higher order instruction remained low during the first four months of the learner stage, even as instruction about vehicle handling/operation decreased. These findings suggest parents are not taking full advantage of the opportunity provided by mandatory periods of supervised driving to help their children develop an understanding of important aspects of driving.     

Do healthy,child-friendly fruit and vegetable snacks appeal to consumers? A field study exploring adults’ perceptions and purchase intentions

The majority of children in the U.S. do not consume enough fruits and vegetables (FV). Children’s liking of and preferences for FV are consistent predictors of intake, as are factors such as availability and accessibility, which are largely under the control of parents and caregivers. This study was designed to examine parents’ and caregivers’ current purchasing habits regarding child-friendly (CF)-shaped foods and pre-cut produce; determine their sensory perceptions of CF-shaped vs. regular-shaped pre-cut FV; and, to ascertain their willingness to pay slightly more for CF-shaped FV compared to fresh, whole produce. Healthy, CF-shaped fruit and vegetable snacks were developed by cutting FV into CF shapes (butterfly, chick, flower, teddy bear). Participants (n = 298) were adults, the majority of whom (66.1%) reported having children at home. Participants who reported having children at home consistently recognized CF-shaped fruit and vegetable samples as CF-shaped foods, while 64.4% of participants with children at home perceived regular-shaped pre-cut fruit and vegetable samples as CF-shaped foods. Participants rated CF-shaped samples as more visually appealing than regular-shaped samples, (p < 0.0001) and were 34% more likely to select CF-shaped samples. Female gender, the presence of children in the home, and frequent self-reported purchase of pre-cut produce were also significant positive predictors of visual appeal. Taste and texture ratings were not consistently significantly higher for CF-shaped fruit and vegetable samples. CF shape predicted higher willingness to pay extra for the fruit and vegetable product (p = 0.0057), as did frequent purchase of pre-cut produce and CF-shaped foods. Adults, particularly females and individuals with children in the household, find CF-shaped FV highly visually appealing and are willing to pay slightly more for these foods. Healthy, ready-to-eat, CF-shaped fruit and vegetable snacks may be a promising marketing strategy to help increase fruit and vegetable intake among children.     

Parent and Child Media Exposure,Preschooler Dietary Intake,and Preschooler Healthy‐Meal Schemas in the Context of Food Insecurity

Media exposure is correlated with child obesity, yet the family behaviors underlying this link remain poorly understood. Using data from a sample of U.S. parents and their preschoolers, this study assessed parent and child exposure to 5 different media along with child dietary intake. Child healthy‐meal schemas were measured with the Placemat Protocol, a novel play‐based pretend meal assembly activity. Child and parent commercial TV viewing predicted greater obesogenic dietary intake for children in food‐secure but not food‐insecure households. Child commercial TV viewing also predicted a greater proportion of energy‐dense to total foods in children's pretend healthy meals. Discussion focuses on food insecurity as a potential moderator of marketing effects and calls for continued research on child meal schema development.