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Variable wind speeds over the ocean can have a significant impact on the formation mechanism and physical-chemical properties of sea spray aerosols (SSA), which in turn influence their climate-relevant impacts. Herein, for the first time, we investigate the effects of wind speed on size-dependent morphology and composition of individual nascent SSA generated from wind-wave interactions of natural seawater within a wind-wave channel as a function of size and their particle-to-particle variability. Filter-based thermal optical analysis, atomic force microscopy (AFM), AFM infrared spectroscopy (AFM-IR), and scanning electron microscopy (SEM) were employed in this regard. This study focuses on SSA with sizes within 0.04-1.8 μm generated at two wind speeds: 10 m/s, representing a wind lull scenario over the ocean, and 19 m/s, indicative of the wind speeds encountered in stormy conditions. Filter-based measurements revealed a reduction of the organic mass fraction as the wind speed increases. AFM imaging at 20% relative humidity of individual SSA identified six main morphologies: prism-like, rounded, core-shell, rod, rod inclusion core-shell, and aggregates. At 10 m/s, most SSA were rounded, while at 19 m/s, core-shells became predominant. Based on AFM-IR, rounded SSA at both wind speeds had similar composition, mainly composed of aliphatic and oxygenated species, whereas the shells of core-shells displayed more oxygenated organics at 19 m/s and more aliphatic organics at 10 m/s. Collectively, our observations can be attributed to the disruption of the sea surface microlayer film structure at higher wind speeds. The findings reveal a significant impact of wind speed on morphology and composition of SSA, which should be accounted for accurate assessment of their climate effects.

Minerals play a critical role in the chemistry occurring along the interface of different environmental systems, including the atmosphere/geosphere and hydrosphere/geosphere. In the past few decades, vibrational spectroscopy has been used as a probe for studying interfacial geochemistry. Here, we compare four different vibrational methods for probing physical and chemical features across different mineral samples and length scales, from the macroscale to nanoscale. These methods include Attenuated Total Reflection - Fourier Transform Infrared (ATR-FTIR), Optical Photothermal Infrared (O-PTIR), Atomic Force Microscopy-Infrared (AFM-IR) and micro-Raman spectroscopy. The emergence of these micro-spectroscopic probes has offered new insights into heterogeneities within geochemical thin films and particles. These developments represent an important step forward for analyzing environmental interfaces and thin films as often these are assumed to be physically and chemically homogeneous. By comparing and integrating data across these measurement techniques, new insights into sample differences and heterogeneities can be gained. For example, interrogation of the various mineral samples at smaller length scales is shown to be particularly informative in highlighting unique chemical environments, including for chemically complex, multicomponent samples such as Arizona Test Dust (AZTD), as well as differences due to crystal orientation.

The effects of atmospheric aging on single-particle nascent sea spray aerosol (nSSA) physicochemical properties, such as morphology, composition, phase state, and water uptake, are important to understanding their impacts on the Earth's climate. The present study investigates these properties by focusing on the aged SSA (size range of 0.1-0.6 μm) and comparing with a similar size range nSSA, both generated at a peak of a phytoplankton bloom during a mesocosm study. The aged SSAs were generated by exposing nSSA to OH radicals with exposures equivalent to 4-5 days of atmospheric aging. Complementary filter-based thermal optical analysis, atomic force microscopy (AFM), and AFM photothermal infrared spectroscopy were utilized. Both nSSA and aged SSA showed an increase in the organic mass fraction with decreasing particle sizes. In addition, aging results in a further increase of the organic mass fraction, which can be attributed to new particle formation and oxidation of volatile organic compounds followed by condensation on pre-existing particles. The results are consistent with single-particle measurements that showed a relative increase in the abundance of aged SSA core-shells with significantly higher organic coating thickness, relative to nSSA. Increased hygroscopicity was observed for aged SSA core-shells, which had more oxygenated organic species. Rounded nSSA and aged SSA had similar hygroscopicity and no apparent changes in the composition. The observed changes in aged SSA physicochemical properties showed a significant size-dependence and particle-to-particle variability. Overall, results showed that the atmospheric aging can significantly influence the nSSA physicochemical properties, thus altering the SSA effects on the climate.

This article analyzes the theoretical properties of the hybrid test for superior predictive ability. A simple example reveals that the test may not be size-controlled at common significance levels with rejection rates exceeding $11\%$ at a $5\%$ nominal level. Generalizing this observation, the main results show the pointwise asymptotic invalidity of the hybrid test under reasonable conditions. Monte Carlo simulations support these theoretical findings. [ABSTRACT FROM AUTHOR]

Initial COVID-19 pandemic research suggests that during the first few weeks of the pandemic women were disproportionately impacted by restrictions compared to men. This study explored whether these gender differences in coping with pandemic restrictions were present among older adults 8–9 months into the COVID-19 pandemic. Data are based on online survey responses (n = 781) from respondents aged 60 and older. The survey was fielded from November 2 to December 4, 2020. Compared to older men, a greater proportion of older women self-reported an increase in being lonely, anxious, scared, sad, stressed, hopeless, and frustrated as compared to the beginning of the pandemic. More women reported engaging in healthy coping behaviors compared to men and self-reported more decreases in sleeping and in eating compared to the first few weeks of the pandemic. A greater proportion of older women reported a decline in physical activity since the first few weeks of the pandemic compared to older men. Self-reported changes in communication did not differ by gender, except for text messaging. More women compared to men reported that their use of text messaging increased since the initial stages of the pandemic. Results showed significant gender differences among older adults in coping with long-term COVID-19 restrictions 8–9 months into the pandemic. [ABSTRACT FROM AUTHOR]

We conducted an exploratory study to describe the emotional experience of adults aged 60 and older in the United States practicing social distancing during COVID-19. The survey asked respondents how they were feeling during social distancing. Responses (n=673) were coded into segments by affect and then specific emotional states. A large portion of respondents reported negative emotions (e.g. anxiety, loneliness). A smaller portion reported positive emotions (e.g. optimism, gratitude). Younger respondents (aged 60-70) reported more feelings of anxiousness and fear compared to older respondents (71+). Older respondents were more likely to report negative feelings towards the government. For both age groups, female respondents were significantly more likely to report feeling afraid and having negative feelings about their own health. We conclude that many older adults are vulnerable to negative emotional outcomes during the pandemic. This highlights the importance of interventions targeting vulnerable older adults. [ABSTRACT FROM AUTHOR]

This paper provides a user's guide to the general theory of approximate randomization tests developed in Canay, Romano, and Shaikh (2017a. "Randomization Tests under an Approximate Symmetry Assumption." Econometrica 85 (3): 1013–30) when specialized to linear regressions with clustered data. An important feature of the methodology is that it applies to settings in which the number of clusters is small – even as small as five. We provide a step-by-step algorithmic description of how to implement the test and construct confidence intervals for the parameter of interest. In doing so, we additionally present three novel results concerning the methodology: we show that the method admits an equivalent implementation based on weighted scores; we show the test and confidence intervals are invariant to whether the test statistic is studentized or not; and we prove convexity of the confidence intervals for scalar parameters. We also articulate the main requirements underlying the test, emphasizing in particular common pitfalls that researchers may encounter. Finally, we illustrate the use of the methodology with two applications that further illuminate these points: one to a linear regression with clustered data based on Meng, Qian, and Yared (2015. "The Institutional Causes of china's Great Famine, 1959–1961." The Review of Economic Studies 82 (4): 1568–611) and a second to a linear regression with temporally dependent data based on Munyo and Rossi (2015. "First-day Criminal Recidivism." Journal of Public Economics 124: 81–90). The companion R and Stata packages facilitate the implementation of the methodology and the replication of the empirical exercises. [ABSTRACT FROM AUTHOR]

Introduction: The recently approved COVID-19 vaccine in 2021 provided a glimmer of hope to all people who had isolated, or lost loved ones to the SARS-COVID-19 virus. Clinics were rapidly established in non-traditional settings in order to meet the need in the early phases of the vaccination program. Contractor support provided rapid personnel support to meet the needs of many locations in several states. Consideration of basic infrastructure requirements such as Incident Command, security, HVAC, electricity, water and sanitation were part of a state supported vaccine clinic in an economically challenged neighborhood in downtown Miami, Florida. Method: Topics to be discussed include staffing mixes, language/cultural concerns, handheld EMR applications, patient flow, immunization practices, testing practices, vaccine security, adverse event management, infection control procedures and the ever present supply chain challenges. The discussion will be framed from the perspective of the Chief Nursing Officer in an ever challenging vaccine environment. Results: Over 20,000 vaccines were successfully provided in a little over three months, and a community-based Student Internship program was also implemented. Conclusion: Vaccine administration is possible in a variety of settings. Foundational principles of vaccine security, management of the environment and provision of safety and security for patients and staff will help to ensure a successful public health campaign. [ABSTRACT FROM AUTHOR]

The Chemical Assessment of Surfaces and Air (CASA) study aimed to understand how chemicals transform in the indoor environment using perturbations ( e.g. , cooking, cleaning) or additions of indoor and outdoor pollutants in a well-controlled test house. Chemical additions ranged from individual compounds ( e.g. , gaseous ammonia or ozone) to more complex mixtures ( e.g. , a wildfire smoke proxy and a commercial pesticide). Physical perturbations included varying temperature, ventilation rates, and relative humidity. The objectives for CASA included understanding (i) how outdoor air pollution impacts indoor air chemistry, (ii) how wildfire smoke transports and transforms indoors, (iii) how gases and particles interact with building surfaces, and (iv) how indoor environmental conditions impact indoor chemistry. Further, the combined measurements under unperturbed and experimental conditions enable investigation of mitigation strategies following outdoor and indoor air pollution events. A comprehensive suite of instruments measured different chemical components in the gas, particle, and surface phases throughout the study. We provide an overview of the test house, instrumentation, experimental design, and initial observations - including the role of humidity in controlling the air concentrations of many semi-volatile organic compounds, the potential for ozone to generate indoor nitrogen pentoxide (N 2 O 5 ), the differences in microbial composition between the test house and other occupied buildings, and the complexity of deposited particles and gases on different indoor surfaces.