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Over the last decade, supercell simulations and observations with ever-increasing resolution have provided new insights into the vortex-scale processes of tornado formation. This article incorporates these and other recent findings into the existing three-step model by adding an additional fourth stage. The goal is to provide an updated and clear picture of the physical processes occurring during tornadogenesis. Specifically, we emphasize the importance of the low-level wind shear and mesocyclone for tornado potential, the organization and interaction of relatively small-scale pretornadic vertical vorticity maxima, and the transition to a tornado-characteristic flow. Based on these insights, guiding research questions are formulated for the decade ahead. SIGNIFICANCE STATEMENT: This article provides a nontechnical overview of how tornadoes form. Sequentially, the most important processes include the initial creation of rotating updrafts, the development of disorganized patches of rotation at the surface, the organization of these patches into a more defined, symmetric vortex, and the final transition into a fully developed tornado in which air turns abruptly upward very near the surface. Based on this proposed conceptual model, guiding research questions are formulated for the decade ahead. KEYWORDS: Tornadogenesis; Severe storms; Tornadoes; Radars/Radar observations; Supercells, 1. How does a tornado form? This is perhaps one of the most elementary yet enduring questions in meteorology. Even though severe-storm research has focused on this problem for over [...]

On 28 May 2019, a tornadic supercell, observed as part of Targeted Observation by UAS and Radars of Supercells (TORUS) produced an EF-2 tornado near Tipton, Kansas. The supercell was observed to interact with multiple preexisting airmass boundaries. These boundaries and attendant air masses were examined using unoccupied aircraft system (UAS), mobile mesonets, radiosondes, and dual-Doppler analyses derived from TORUS mobile radars. The cool-side air mass of one of these boundaries was found to have higher equivalent potential temperature and backed winds relative to the warm-side air mass; features associated with mesoscale air masses with high theta-e (MAHTEs). It is hypothesized that these characteristics may have facilitated tornadogenesis. The two additional boundaries were produced by a nearby supercell and appeared to weaken the tornadic supercell. This work represents the first time that UAS have been used to examine the impact of preexisting airmass boundaries on a supercell, and it provides insights into the influence environmental heterogeneities can have on the evolution of a supercell. [ABSTRACT FROM AUTHOR]

There are few areas of school organization that reflect more dissatisfaction than how to structure the education of adolescents in the middle grades. This study uses multilevel models on nationally representative data provided by the Early Childhood Longitudinal Study to investigate the relationship between schools' middle-level grade span and students' math achievement. Classroom quality was considered as an explanation for any relationships between grade span and achievement. Also examined was whether gender and family structure moderated this relationship. Results indicate that there is no generalizable relationship between grade span configuration and math achievement, but that measures of classroom quality predicted math achievement. The results should give reflective pause to reformers considering whole-scale changes to the ways in which grade spans are organized and sharpen the policy focus on classroom quality.

This paper investigates the relationship between student engagement--with teachers and schools--and academic performance in Mexico. It uses hierarchical linear models and data from the OECD 2003 PISA study to examine the relative importance of engagement in comparison to other educational inputs--school and family characteristics--as predictors of performance. Our findings suggest that stronger engagement with the school positively affects students' achievement. The estimates are similar to those of socioeconomic status or family composition. However, stronger engagement with teachers does not necessarily improve achievement, and can even negatively correlate with performance. The findings provide an insightful approach to understanding the educational process by incorporating a greater diversity of schooling factors, and support the need for evidence of the factors that make up engagement with different school aspects. Additionally, they speak to the influence of policies that contribute to student engagement that may improve academic performance for Mexican students.

We examine a set of academic and social outcomes in 9th grade, comparing middle school attendees with those who attended K-8 schools. Previous research with these data has shown that there are few differences in 8th-grade outcomes by school type. Here we extend these findings to determine whether school form influences student outcomes in the first year of high school. The results reveal several domains in which attendance at a middle school results in worse outcomes (e.g., greater rates of course failure); however, we find that a large portion of the difference by type of a student's 8th-grade school is accounted for by differential rates of attendance at the district's magnet schools. That is, our results indicate that type of school attended during the middle grades is significantly and "positively" related to magnet school attendance and thereby on the academic outcomes in the 9th-grade year.

In an effort to increase both adolescents' engagement with school and academic achievement, school districts across the United States have created small high schools. However, despite the widespread adoption of size reduction reforms, relatively little is known about the relationship between size, engagement and outcomes in high school. In response, this article employs a composite measure of engagement that combines organizational, sociological, and psychological theories. We use this composite measure with the most recent nationally-representative dataset of tenth graders, Educational Longitudinal Study: 2002, (N = 10,946, 46% female) to better assess a generalizable relationship among school engagement, mathematics achievement and school size with specific focus on cohort size. Findings confirm these measures to be highly related to student engagement. Furthermore, results derived from multilevel regression analysis indicate that, as with school size, moderately sized cohorts or grade-level groups provide the greatest engagement advantage for all students and that there are potentially harmful changes when cohorts grow beyond 400 students. However, it is important to note that each group size affects different students differently, eliminating the ability to prescribe an ideal cohort or school size.

Seemingly endless tinkering and adjustment of the structure of education in the United States over the past century have led to the adoption of different school forms (grouping particular grades into separate schools) at different times. These different school forms necessitate transitions between schools (e.g., from a middle school to a high school), which, prior research has argued, have detrimental effects on students' well-being. In this article, we use natural variation in the American educational system to reexamine the effects of school transitions. Contrary to most prior research on the subject, we directly compare the ninth-grade outcomes of students who make a transition in moving to ninth grade with those who do not. Our results show that for both academic and nonacademic outcomes, the presence of a transition from eighth grade to ninth grade makes almost no difference for students' ninth-grade outcomes relative to those of students who do not change schools between those grades. This is not to suggest that outcomes do not change between eighth grade and ninth grade but that the degree of difference is the same for students who change schools as for those who do not. Where differences appear, they are small and point to the benefits of school transitions for providing fresh starts to adolescents in socially difficult situations.

The period of the middle grades has seen numerous reforms to improve education for students in early adolescence. However, although several current reforms seek to overhaul middle schools, only a handful of studies have directly compared the effects of different configurations of grades. Our analysis uses district and student data from one of the few American urban districts that contain both middle schools and K-8 schools. We compare student outcomes in eighth grade, finding few differences by school type. Only self-esteem and perceived threat differ by type of eighth-grade school. We also show that students' self-esteem benefits academic outcomes, a benefit that primarily accrues to students in middle schools.

Examined how students' grades were affected by disruptions at the beginning of the school year. Data from student-parent interviews in a large urban district indicated that disruption was widespread in ninth grade. Students who experienced more turbulence received significantly lower grades. Significant levels of between-school differences in turbulence related to higher levels of student variation and turnover. (SM)

Examined role of support from a well-adjusted older sibling for positive adjustment of disadvantaged inner-city adolescents. Found that sibling support was nonsignificantly related to delinquency, academic success, and mental health for younger siblings. Only when accompanied by a positive image of their older sibling was support associated with positive adjustment for younger siblings. (Author)

Using the third wave of the Philadelphia Teen Survey, estimates cross-classified two-level models to see how much between-census tract and between-school variability exists in the timing of youth's sexual initiation. Attempts to assess the extent that race and normative environments of schools account for between-school variability in the timing of youth's sexual initiation. (CMK)

In response to the recognized need for a training system to support an integrated food safety system in the U.S., the International Food Protection Training Institute (IFPTI) in Battle Creek, Michigan, designed a career-spanning curriculum framework. IFPTI collaborated with a national curriculum team consisting of regulatory officials and university academics. The curriculum framework encompasses and organizes existing professional development for the estimated 45,000 federal, state, and local food regulators in the U.S. into efficient, standards-driven learning paths. This article describes the development process leading to an integrated national food protection training curriculum framework., Introduction The need for a consistent and accessible standards-based training regimen for regulatory food protection professionals has been determined to be of national strategic importance as a result of a [...]

Numerous previous works have shown that vertical shear in wind speed and wind direction exist in the atmospheric boundary layer. In this work, meteorological forcing mechanisms, such as the Ekman spiral, thermal wind, and inertial oscillation, are discussed as likely drivers of such shears in the statically stable environment. Since the inertial oscillation, the Ekman spiral, and statically stable conditions are independent of geography, potentially significant magnitudes of speed and direction shear are hypothesized to occur to some extent at any inland site in the world. The frequency of occurrence of non-trivial magnitudes of speed and direction shear are analyzed from observation platforms in Lubbock, Texas and Goodland, Indiana. On average, the correlation between speed and direction shear magnitudes and static atmospheric stability are found to be very high. Moreover, large magnitude speed and direction shears are observed in conditions with relatively high hub-height wind speeds. The effects of speed and direction shear on wind turbine power performance are tested by incorporating a simple steady direction shear profile into the fatigue analysis structures and turbulence simulation code from the National Renewable Energy Laboratory. In general, the effect on turbine power production varies with the magnitude of speed and direction shear across the turbine rotor, with the majority of simulated conditions exhibiting power loss relative to a zero shear baseline. When coupled with observational data, the observed power gain is calculated to be as great as 0.5% and depletion as great as 3% relative to a no shear baseline. The average annual power change at Lubbock is estimated to be -0.5%. [DOI: 10.1115/1.3035818] Keywords: direction shear, speed shear, tall-tower observations, power production, stable boundary layer, FAST, low-level jet, thermal wind, inertial oscillation, Ekman spiral

Objectives. We sought to test whether the association between walkable environments and lower body mass index (BMI) was stronger within disadvantaged groups that may be particularly sensitive to environmental constraints. Methods. We measured height and weight in a diverse sample of 13102 adults living throughout New York City from 2000-2002. Each participant's home address was geocoded and surrounded by a circular buffer with a 1-km radius. The composition and built environment characteristics of these areas were used to predict BMI through the use of generalized estimating equations. Indicators of individual or area disadvantage included low educational attainment, low household income, Black race, and Hispanic ethnicity. Results. Higher population density, more mixed land use, and greater transit access were most consistently associated with a lower BMI among those with more education or higher incomes and among non-Hispanic Whites. Significant interactions were observed for education, income, race, and ethnicity. Conclusions. Contrary to expectations, built environment characteristics were less consistently associated with BMI among disadvantaged groups. This pattern may be explained by other barriers to maintaining a healthy weight encountered by disadvantaged groups. (Am J Public Health. 2009;99:279-284. doi:10.2105/ AJPH.2008.138230)

The purpose of this article is to examine the long-term consequences of paternal involvement for a sample of young men, with the intent being to examine whether patterns of fatherhood are transmitted across generations. Initially, a theoretical framework is discussed that has led researchers to expect that patterns of fatherhood will be produced across generations. Data from the Baltimore Parenthood Study were used, a 30-year longitudinal study that has followed the reproductive patterns of teenage parents and their children. A subsampie of 110 males were examined with an occasional reference made to a subsample of females. Results indicated that a strong link existed between the stable presence of a biological father in the histories of the young men and the timing of their own family formation. Early fatherhood, both during the teen years and early twenties, is much more likely to occur if young men did not grow up living with their own fathers. Moreover, early fatherhood is somewhat more likely to occur if the young men did not have a stepfather in the past who was a stable presence in the home. Young fathers also were less likely to be living with their children if their own fathers had not lived in residence with them throughout childhood.

To test whether the effects of marital status on health differ between never married women and divorced and separated women, this study utilizes prospective panel data for a large national sample of non-institutionalized young women in the U.S. (the National Longitudinal Surveys of Young Women). The women were aged 24-34 at the beginning of two successive five-year follow-up intervals (1978-1983 and 1983-1988). The health effects of marital status were evaluated in regressions which assessed the relationships between initial marital status and subsequent health trends in each follow-up interval. In the first follow-up interval, never married women tended to have worse health trends than divorced and separated women for physical impairments and for overall health problems. However, there were no differences between never married women and divorced and separated women in health trends for psychosomatic symptoms in either follow-up interval or for any health measure in the second follow-up interval. Our analyses of cross-sectional data showed few significant differences in health between never married women and divorced and separated women. Taken together, the evidence from our study and previous studies suggests that differences between never married women and divorced and separated women may vary by age and/or cohort. Evidence for the 1970s and 1980s suggests that, among older women, divorced and separated women may have experienced more harmful health effects than never married women; however, among younger women, this difference may have been absent or possibly reversed. Key words - marital status, divorce, women