Using a Social Experiment to Validate a Dynamic Behavioral Model of Child Schooling and Fertility: Assessing the Impact of a School Subsidy Program in Mexico

This paper studies the performance of a methodology that can be used to evaluate the impact of new policies that radically depart from existing ones. It uses data gathered from a randomized schooling subsidy experiment in Mexico (i) to estimate and validate a dynamic behavioral model of parental decisions about fertility and child schooling, (ii) to forecast long-term program impacts that extend beyond the life of the experiment, and (iii) to assess the impact of a variety of counterfactual policies. The behavioral model is estimated using data on families in the randomized-out control group and in the treatment group prior to the experiment, both of which did not receive any subsidy. Child wages provide a valuable source of variation in the data for identifying subsidy effects. Using the estimated model, we predict the effects of school subsidies according to the schedule that was implemented under the Mexican PROGRESA program.schooling, child labor, fertility, structural estimation, social experiments

The Production of Cognitive Achievement in Children: Home, School and Racial Test Score Gaps

This paper studies the determinants of children’s scores on tests of cognitive achievement in math and reading. Using rich longitudinal data on test scores, home environments, and schools, we implement alternative specifications for the production function for achievement and test their assumptions. We do not find support for commonly used restrictive models that assume test scores depend only on contemporaneous inputs or that assume conditioning in a lagged score captures the effects of all past inputs. Instead, the results show that both contemporaneous and lagged inputs matter in the production of current achievement and that it is important to allow for unobserved child-specific endowment effects and endogeneity of inputs. Using a specification that incorporates these features, we analyze sources of test score gaps between black, white and Hispanic children. The estimated model captures key patterns in the data, such as the widening of minority-white test score gaps with age, which is most pronounced for black children.Education production function, racial test score gaps, school quality, child development and cognitive achievement

Ex Ante Evaluation of Social Programs

This paper discusses methods for evaluating the impacts of social programs prior to their implementation. Ex ante evaluation is useful for designing programs that achieve some optimality criteria, such as maximizing impact for a given cost. This paper illustrates through several examples the use of behavioral models in predicting the impacts of hypothetical programs. Among the programs considered are wage subsidy programs, conditional cash transfer programs, and income support programs. In some cases, the behavioral model justifies a completely nonparametric estimation strategy, even when there is no direct variation in the policy instrument. In other cases, stronger modeling and/or functional form assumptions are required to evaluate a program ex ante. We illustrate the application of ex ante evaluation methods using data from the PROGRESA school subsidy experiment in Mexico. We assess the effectiveness of the method by comparing ex ante predictions of program impacts to the impacts measured under the randomized experiment.ex-ante evaluation, matching, evaluation methods, school subsidy programs

Preparation of Cu-based bulk metallic glasses by suction casting

A series of Cu-Hf-Ti alloys prepared by rapid solidification of the melt and by copper mould casting were studied in the present work. Alloy ingots were prepared by arc-melting mixtures of pure metals in an argon atmosphere. An indication of the cooling rate obtained was determined using an Al-4.5 wt%Cu alloy. Cooling rates varied from 540 K/s for the centre section of a 4 mm die to 885 K/s for the outside wall section of the 2 mm die. The glass-forming ability, structure and thermal stability of Cu-Hf-Ti glassy alloys were studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and differential thermal analysis (DTA). Bulk glass formation was observed for the Cu64Hf36, Cu55Hf25Ti20 and Cu56Hf25Ti19 alloys, with critical diameters dc for a fully glassy structure of 1, 4 and 5 mm, respectively. The substitution of Hf by Ti increased the glassforming ability (GFA) and the thermal stability

A preliminary investigation of spinal kinematics during sugar cane harvesting

The sugar cane industry forms a significant portion of the South African economy, and unlike many other countries the harvesting of sugar cane in South Africa remains manual in nature. The focus of the present study was therefore on the assessment of spinal kinematics (range of motion, velocities and accelerations in all three cardinal planes) during the harvesting process. Eight workers were recruited from the Illovo Esperanza farm in Kwa-zulu Natal as subjects for the study. The experimental protocol was conducted in situ and required subjects to cut the sugar cane using specially modified knives as they would under normal harvesting conditions. The motion performance was quantified using the lumbar motion monitor (LMM), a triaxial electrogoniometer. Results indicate that the harvesting of sugar cane places excessive demands on the spine. During cutting, subjects were required to maintain the spine in a high degree of flexion throughout the task which also demonstrated significant twisting and lateral bending. Of particular concern were the high lateral velocities (ranging between 50 and 90 m.s-1), as this is a key risk factor in the development of lower back pain. It is evident from these results that new techniques of harvesting sugar cane are essential to reduce the rate of injury within this industry

Elementary Educators\u27 Attitudes about the Utility of Educational Robotics and Their Ability and Intent to Use It with Students

Educational robotics (ER) combines accessible and age-appropriate building materials, programmable interfaces, and computer coding to teach science and mathematics using the engineering design process. ER has been shown to increase K-12 students\u27 understanding of STEM concepts, and can develop students\u27 self-confidence and interest in STEM. As educators struggle to adapt their current science teaching practices to meet the new interdisciplinary nature of the Next Generation Science Standards, ER has the potential to simultaneously integrate STEM disciplines, engage and inspire students in mathematics and science, and build connections to STEM careers. One challenge is a lack of documented models for preparing educators, particularly at the elementary level, to effectively use robotics in their classrooms. The lack of scholarship on appropriate robotics platforms for elementary learners, reliable techniques of delivering professional development in ER, or standardized instruments that can reliably measure elementary educators\u27 self-efficacy with robotics suggests there is a need for such research. The primary purpose of this study was to investigate the impact of a four-hour, hands-on, ER professional development workshop on K-5th grade educators\u27 attitudes about their ability to teach ER, the value (utility) of the technology, and their desire to use it (intent). An 18-question survey was administered before (pre-) and after (post-) the workshop, as well as a third time after educators had an opportunity to use robotics with students (post-post). In order to extend and explain the quantitative data, 60% of the educators who completed all three surveys were also interviewed. This study sought to determine if any of the trained educators also participated in after-school robotics competitions, and if so what impact that had on their attitudes of using ER. Results comparing the pre to post workshop means determined that there were statistically significant differences with large effect sizes in educators\u27 attitudes across all three subscales. The interviews supported the conclusion that the workshop and classroom kits are important for successful implementation of ER in classrooms. Post use surveys did not result in statistically significant differences in educators\u27 attitudes, demonstrating persistence of attitudes consistent with the interview results that revealed educators value the hands-on nature of ER which they believe increases student engagement in STEM and cross-curricular learning. A case-study of one educator suggests that participation in FIRSTRTM LEGORTM League Jr. increased the skills, confidence, and engagement of both the teacher and students which led to the integration of engineering practices, and school-wide interest in ER. This study demonstrates the importance of high-quality professional development in increasing educators\u27 self-efficacy with using ER with elementary students, and suggests that new tablet-based, wireless robotics platforms, such as the LEGORTM WeDo 2.0 enable younger learners to engaged with this technology. Additional research is necessary to better understand the impact of ER on students, and to identify and study schools where ER helped lead a transformation of the teaching toward constructionism. It is vital for the success of our children and our nation that we engage and inspire students in STEM subjects and career pathways at an early age if we are to meet the needs of the 21st century job market, reduce disparities in STEM fields, and maintain our place in the global economy

The consequences of goods perishing subsequent to a contract having been entered into for their sale

The thesis comprises three Parts, together with a preface and an addendum. Each of the Parts focuses upon one of the three inter-related concepts applicable where there is a post-contract perishing of goods. The concepts of "perishing", "risk" and "frustration" are separately analysed so as to identify their individual characteristics and in order that facets of their inter-relationship may emerge. Part One, which deals with the meaning of "perishing", is more descriptive in nature than the other two Parts, for, when considered in isolation, the issues raised in that Part are relatively straightforward. It is only when those same issues are re-considered, in the context of the concepts of risk and frustration, that their significance becomes apparent. In Part Two, an analysis is made of the meaning of "risk" and instances of the divisibility of risk are examined. Different views of the mishaps provided for by the statutory term "risk" are assessed and, as part of that exercise, the meaning of "perished" is re-appraised. An analysis is made, in Part Three, of the rules which provide for frustration of a contract of sale and for the consequences resulting from such frustration. An attempt is made to identify instances in which a contract of sale may be frustrated even though property, or risk, or, indeed, both property and risk, have passed to the buyer prior to the goods perishing. In the addendum to the thesis an opportunity is taken to re-examine the concepts of "perishing", "risk" and "frustration" in a context in which, the separate concepts having already been analysed and detailed statutory and common law provisions scrutinised, there is freedom to bring together strands which have emerged from the various Parts of the thesis. This opportunity is taken in an attempt to fix the relationship between the concepts

Misinformation and Vaccine Hesitancy Determinants: The Significance of Framed Public Health Messaging

In 2020, the SARS-CoV-2 (COVID19) outbreak effectively disrupted worldwide operation for months, leading to tremendous economic loss and adverse health outcomes. While countries grappled to control the virus and scientists worked around the clock to deliver a vaccine in record time, a pubic health communication crisis emerged. The spread of false and misleading information, also known as misinformation, has proved to be a barrier in the fight against COVID19 and its vaccination effort. Many factors including the rise of social media, distrust of government, polarization of news sources, and fragmented media have created an environment susceptible to misinformation. Utilized correctly, health messaging has the potential to be a tremendous resource for health promotion and messaging, especially during emergency situations. Framed messaging, when tailored to target and appeal to a specific population may serve to alleviate the effects of misinformation, specifically when targeting under-vaccinated groups. The relevance of this project is that it attempts to bring focus to the emergence of misinformation, and explores strategies deployed by regional public health departments across Nebraska. To this end, the goal of this work is to information future public health organizations about the options for successful public health messaging and guidance. A literature review was conducted, which collected and reviewed studies centered around messaging, vaccine hesitancy, and misinformation. A qualitative assessment was also conducted, through interview with four local Nebraska health department personnel to determine their actions and perceptions of the uses and power of misinformation. Interview questions centered around messaging strategies. Based on the results of the qualitative data, framed health messaging was effective in decreasing misinformation and increasing vaccine rates and might be a worthwhile strategy. However, further research is needed to determine how public health can be more effective in messaging framing to combat misinformation

Commentary: Umbrella synthesis of meta‐analyses on child maltreatment antecedents and interventions – a commentary on van IJzendoorn and colleagues (2020)

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154443/1/jcpp13175_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154443/2/jcpp13175.pd

Random matrices, non-backtracking walks, and orthogonal polynomials

Several well-known results from the random matrix theory, such as Wigner's law and the Marchenko--Pastur law, can be interpreted (and proved) in terms of non-backtracking walks on a certain graph. Orthogonal polynomials with respect to the limiting spectral measure play a role in this approach.Comment: (more) minor change