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Teaching chemistry without access to a traditional laboratory space is an ongoing challenge that has become especially relevant because of the SARS-CoV-2 pandemic. While several remote learning options exist for covering general chemistry concepts (including kitchen-based experiments, online modules, and virtual reality), few options provide opportunities for hands-on learning about the chemistry of synthetic polymer materials. Here, we offer remote learning modules that use household adhesives as a platform for teaching polymer chemistry outside of the laboratory. These modules are designed for students who have taken at least one semester of organic chemistry and have varied hands-on time commitments, ranging from 2 to 10 total hours each. Concepts covered include polymer synthesis, intermolecular interactions, thermomechanical properties, structure-function relationships, and molecular design. The experiments described in these modules also give students a chance to practice research-relevant skills such as searching for primary literature sources, fabricating test samples, explaining unexpected experimental results, and revising experimental procedures to improve methodologies. Ultimately, these modules provide educators with an additional tool for teaching experimental chemistry outside of the laboratory.

This paper develops a simple approach to overcome the shortcomings of using a standard, single treatment-effect event study to assess the ability of an empirical model to measure heterogeneous treatment effects. Equally as important, we discuss how the standard errors reported in a typical event-study analysis for the posttreatment event-time effects are, without additional information, of limited use for assessing posttreatment variations in the treatment effects. The simple reformulation of the standard event-study approach described and illustrated with artificially constructed data in this paper overcomes the limitations of conventional event-study analyses. JEL classification: C22, C23 Key words: event studies, heterogeneous treatment effects, I. Introduction The event study is often used to provide a visual overview of the impact of a change in policy on behavior and outcomes. According to Currie, Kleven, and [...]

We use measurements of trace gases from the Microwave Limb Sounder and polar stratospheric clouds (PSCs) from the Cloud‐Aerosol Lidar with Orthogonal Polarization to investigate how the extraordinary stratospheric water vapor enhancement from the 2022 Hunga eruption affected polar processing during the 2023 Antarctic winter. Although the dynamical characteristics of the vortex itself were generally unexceptional, the excess moisture initially raised PSC formation threshold temperatures above typical values. Cold conditions, especially in early July, prompted ice PSC formation and unusually severe irreversible dehydration at higher levels (500–700 K), while atypical hydration occurred at lower levels (380–460 K). Heterogeneous chemical processing was more extensive, both vertically (up to 750–800 K) and temporally (earlier in the season), than in prior Antarctic winters. The resultant HCl depletion and ClO enhancement redefined their previously observed ranges at and above 600 K. Albeit unmatched in the satellite record, the early‐winter upper‐level chlorine activation was insufficient to induce substantial ozone loss. Chlorine activation, denitrification, and dehydration processes ran to completion by July/August, with trace gas evolution mostly following the climatological mean thereafter, but with chlorine deactivation starting slightly later than usual. While cumulative ozone losses at 410–550 K were relatively large, probably because of the delayed chlorine deactivation, they were not unprecedented. Thus, ozone depletion was unremarkable throughout the lower stratosphere. Although Hunga enhanced PSC formation and chemical processing in early winter, saturation of lower stratospheric denitrification, dehydration, and chlorine activation (as is typical in the Antarctic) prevented an exceptionally severe ozone hole in 2023. Plain Language Summary: The 2022 eruption of the Hunga volcano produced an increase in stratospheric water vapor unmatched in the satellite record. Excess moisture pervaded the Antarctic stratosphere at the beginning of the 2023 Southern Hemisphere winter. Cold moist conditions prompted formation of ice clouds in the Antarctic stratosphere at higher altitudes than usual. Falling ice particles caused unusually severe permanent removal of water vapor from these levels and deposited it at lower altitudes. Chemical processing on polar stratospheric cloud particles occurred both earlier in the season and over a broader vertical domain than typical, resulting in exceptional early‐winter upper‐level conversion of chlorine from nonreactive into ozone‐destroying forms. Chemical processing ran its course by midwinter (i.e., July/August), with trace gases, including ozone, mostly following average behavior thereafter. Deactivation (reconversion of chlorine into nonreactive forms) started slightly later than in most years. While cumulative seasonal ozone losses were relatively large at some levels, probably because of the delayed chlorine deactivation, they were not unprecedented. Thus, although Hunga accelerated and expanded the vertical extent of chemical processing in early winter, that chemical processing reached completion as usually happens in Antarctic midwinter, preventing an extraordinarily severe ozone hole in 2023. Key Points: Hydration from Hunga led to unusually early and vertically extensive polar stratospheric cloud activity in the 2023 Antarctic vortexAs a result, heterogeneous chlorine activation occurred weeks earlier and at higher altitudes and dehydration removed more H2O than typicalDespite exceptional early‐winter conditions, cumulative ozone losses were unremarkable because stratospheric chemical processing saturated [ABSTRACT FROM AUTHOR]

We develop, apply, and test a new measure of the marriage tax: the reduction in future spending from getting married. Our measure is a comprehensive, actuarial (expected) present value. It incorporates all major and most minor US tax and benefit programs, weighing the present value of additional net taxes from marrying along each marital survivor path by the path's probability. And it assumes clone marriage-marrying oneself-to ensure the living-standard loss from marrying is unaffected by spousal choice. We calculate our marriage tax for young respondents using the Survey of Consumer Finances (SCF). The marriage tax rate-the percentage reduction in expected future spending from marrying-averages 2.69 percent. This sample-weighted average is comparable to losing several years of earnings and is much higher in some states than others. Average marriage tax rates are also highly income dependent. Nationwide, the average marriage penalty imposed on people with low incomes is roughly twice that levied on the rich. Low-income females with children face particularly stiff marrying penalties, primarily in the form of lost benefits, both in-cash or in-kind. The variation in marriage taxation is particularly striking and ranges, across our sample, from negative 74.4 percent to positive 45.8 percent. We use the American Community Survey to study the impact of our marriage tax (imputed via a SCF statistical match) on marrying rates. Our tax on remaining lifetime spending matters-a lot. This is particularly true for low-income, single females with children. Absent the tax, 13.7 percent more would marry each year. Cumulatively, 7.5 percent more would be married at age 35. These are much larger effects than arise using the conventional marriage-tax measure. Our findings are robust to adjusting for partial benefit take-up and respondents marrying higher- or lower-income versions of themselves. Given the importance of marriage to child development and a host of economic indicators, heavily penalizing marriage might have far-reaching, deleterious consequences. JEL classification: H2, H31, J12, J18 Key words: marriage taxation, disincentives, marriage, social safety net, income tax https://doi.org/10.29338/wp2022-06, 1 Introduction Marriage, at least in the U.S., matters. It stabilizes relationships (Lundberg et al. 2016; Waite 1995), improves children's outcomes (Amato 2005; DeLeire and Lopoo 2010; McLanahan and Sawhill [...]

Cigarette smokers earn significantly less than nonsmokers, but the magnitude of the smoking wage gap and the pathways by which it originates are unclear. Proposed mechanisms often focus on spot differences in employee productivity or employer preferences, neglecting the dynamic nature of human capital development and addiction. In this paper, we formulate a dynamic model of young workers as they transition from schooling to the labor market, a period in which the lifetime trajectory of wages is being developed. We estimate the model with data from the National Longitudinal Survey of Youth, 1997 Cohort, and we simulate the model under counterfactual scenarios that isolate the contemporaneous effects of smoking from dynamic differences in human capital accumulation and occupational selection. Results from our preferred model, which accounts for unobserved heterogeneity in the joint determination of smoking, human capital, labor supply, and wages, suggest that continued heavy smoking in young adulthood results in a wage penalty at age 30 of 14.8 percent and 9.3 percent for women and men, respectively. These differences are less than half of the raw mean difference in wages at age 30. We show that the contemporaneous effect of heavy smoking net of any life-cycle effects explains roughly 67 percent of the female smoking wage gap but only 11 percent of the male smoking wage gap. JEL classification: I10, I12 Key words: wages, smoking; dynamic system of equations, 1 Introduction Smoking cigarettes is associated with well-documented expected longevity (Doll et al., 2004; Darden et al., 2018) and health care expenditure (Sloan et al., 2006; Xu et al., 2015) [...]

This paper applies a standard treatment effects model to determine that participation in Freshman Learning Communities improves academic performance and retention. Not controlling for individual self-selection into Freshman Learning Communities participation leads one to incorrectly conclude that the impact is the same across race and gender groups. Accurately assessing the impact of any educational program is essential in determining what resources institutions should devote to it. A table with the reduced-form of OLS estimation for earned hours, full sample, is appended. (Contains 6 tables and 18 notes.)

In response to a high incidence of motor vehicle accidents among teens, states have adopted policies that broadly mandate restrictions on novice teen drivers, including more prelicensure education and supervised driving as well as postlicensure curfews and restrictions on the number of passengers. By making it costlier to obtain a driver's license and reducing the benefits of a license by limiting driving hours and restricting passengers, graduated driver licensing (GDL) may also alter the cost of activities that are complementary to driving. This research explores the unintended consequences GDL laws may have on the labor/leisure tradeoff of teens, as it alters the return to market work and the benefit of leisure. The results suggest that approximately half of the decline in teen labor force participation since 1995 can be attributed to the restrictions associated with graduated driver licenses. JEL classification: J22, I18, H7 Key words: graduated driver licensing, teen labor force participation, driving restriction, Introduction In response to a high incidence of motor vehicle accidents among teens, states have adopted policies that broadly mandate restrictions on novice teen drivers. By 2012, all states had [...]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.icarus.2008.12.045 Byline: K.J. Meech (a), J. Pittichova (a), A. Bar-Nun (b), G. Notesco (b), D. Laufer (b), O.R. Hainaut (c), S.C. Lowry (d), D.K. Yeomans (e), M. Pitts (a) Keywords: Ices; Comets; composition; Comets; origin; Photometry Abstract: We present observational data for two long-period and three dynamically new comets observed at heliocentric distances between 5.8 to 14.0 AU. All of the comets exhibited activity beyond the distance at which water ice sublimation can be significant. We have conducted experiments on gas-laden amorphous ice samples and show that considerable gas emission occurs when the ice is heated below the temperature of the amorphous-crystalline ice phase transition (T[approximately equal to]137 K). We propose that annealing of amorphous water ice is the driver of activity in comets as they first enter the inner Solar System. Experimental data show that large grains can be ejected at low velocity during annealing and that the rate of brightening of the comet should decrease as the heliocentric distance decreases. These results are consistent with both historical observations of distant comet activity and with the data presented here. If observations of the onset of activity in a dynamically new comet are ever made, the distance at which this occurs would be a sensitive indicator of the temperature at which the comet had formed or represents the maximum temperature that it has experienced. New surveys such as Pan STARRS, may be able to detect these comets while they are still inactive. Author Affiliation: (a) Univ. Hawai'i, Institute for Astronomy, 2680 Woodlawn Drive, Honolulu, HI 96822, USA (b) Tel Aviv University, Dept. of Geophysics and Planetary Sciences, Tel Aviv 69978, Israel (c) European Southern Observatory, Casilla 19001, Santiago 19, Chile (d) Jet Propulsion Lab, MS 183-301, 4800 Oak Grove Drive, Pasadena, CA 91109, USA (e) Jet Propulsion Laboratory, MS 301-150, Pasadena, CA 91109-8099, USA Article History: Received 24 June 2008; Revised 26 October 2008; Accepted 23 December 2008