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A simple analytical solution is presented for approximating the time-dependent beach-profile response to severe storms. This solution is in the form of a convolution integral involving a time-varying erosion-forcing function and an exponential erosion-response function. The erosion-forcing function reflects changes in the nearshore water level and breaking wave height. In this paper, an idealized storm-surge hydrograph is considered from which an analytic solution is obtained for beach and dune erosion associated with severe storms such as hurricanes or northeasters. It is shown that for a given initial beach geometry and sediment size, the peak water level and the incipient breaking wave height determine the maximum erosion potential that would be achieved if the beach were allowed to respond to equilibrium. Because of the assumed exponential erosion rate, beach response obtained from the convolution method is found to lag the erosion forcing in time, and is damped relative to the maximum erosion potential such that only a fraction of the equilibrium response actually occurs.

Home health and home care (HH&HC) agencies provide essential medical and supportive services to elders and people with disabilities, enabling them to live at home. Home-based care is an important alternative to facility-based care, especially for infection prevention during the COVID-19 pandemic. The majority of the HH&HC workforce is comprised of aides, who also are vulnerable to COVID-19. There are limited data on the COVID-19 experience of HH&HC agencies, clients and aides. A survey of Massachusetts HH&HC agency managers was conducted June 1 to 30, 2020 to assess the impact of COVID-19 on agencies, clients, and aides early in the pandemic and to identify needs for future pandemic planning. Of the 94 agencies with completed surveys, most (59.6%) provided services to clients with COVID-19 and 3-quarters (73.7%) employed aides who tested positive for COVID-19, were symptomatic, and/or quarantined. Most agencies (98.7%) experienced a decrease in demand for home visits, reflecting clients' concern about infection, family members assuming care duties, and/or aides being unavailable for work. Simultaneously, managers' workloads increased to develop more extensive infection prevention policies, procedures and workforce training and sourcing scarce personal protective equipment (PPE). The COVID-19 pandemic imposed substantial new infection prevention responsibilities on HH&HC agencies, clients, and aides. Specific HH&HC needs for future pandemic planning include complete information on the infection status of clients; ready access to affordable PPE and disinfectants; and guidance, tools, and training tailored for the industry. HH&HC should be incorporated more fully into comprehensive healthcare and public health pandemic planning. [ABSTRACT FROM AUTHOR]

It remains uncertain whether the hypertension (HT) medications angiotensin‐converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARB) mitigate or exacerbate SARS‐CoV‐2 infection. We evaluated the association of ACEi and ARB with severe coronavirus disease 19 (COVID‐19) as defined by hospitalization or mortality among individuals diagnosed with COVID‐19. We investigated whether these associations were modified by age, the simultaneous use of the diuretic thiazide, and the health conditions associated with medication use. In an observational study utilizing data from a Massachusetts group medical practice, we identified 1449 patients with a COVID‐19 diagnosis. In our study, pre‐infection comorbidities including HT, cardiovascular disease, and diabetes were associated with increased risk of severe COVID‐19. Risk was further elevated in patients under age 65 with these comorbidities or cancer. Twenty percent of those with severe COVID‐19 compared to 9% with less severe COVID‐19 used ACEi, 8% and 4%, respectively, used ARB. In propensity score‐matched analyses, use of neither ACEi (OR = 1.30, 95% CI 0.93 to 1.81) nor ARB (OR = 0.94, 95% CI 0.57 to 1.55) was associated with increased risk of severe COVID‐19. Thiazide use did not modify this relationship. Beta blockers, calcium channel blockers, and anticoagulant medications were not associated with COVID‐19 severity. In conclusion, cardiovascular‐related comorbidities were associated with severe COVID‐19 outcomes, especially among patients under age 65. We found no substantial increased risk of severe COVID‐19 among patients taking antihypertensive medications. Our findings support recommendations against discontinuing use of renin–angiotensin system (RAS) inhibitors to prevent severe COVID‐19. [ABSTRACT FROM AUTHOR]

Abstract The eruption of genetic research presents a tremendous opportunity to epidemiologists to improve our ability to identify causes of ill health. Epidemiologists have enthusiastically embraced the new tools of genomics and proteomics to investigate gene-environment interactions. We argue that neither the full import nor limitations of such studies can be appreciated without clarifying underlying theoretical models of interaction, etiologic fraction, and the fundamental concept of causality. We therefore explore different models of causality in the epidemiology of disease arising out of genes, environments, and the interplay between environments and genes. We begin from Rothman's "pie" model of necessary and sufficient causes, and then discuss newer approaches, which provide additional insights into multifactorial causal processes. These include directed acyclic graphs and structural equation models. Caution is urged in the application of two essential and closely related concepts found in many studies: interaction (effect modification) and the etiologic or attributable fraction. We review these concepts and present four important limitations. 1. Interaction is a fundamental characteristic of any causal process involving a series of probabilistic steps, and not a second-order phenomenon identified after first accounting for "main effects". 2. Standard methods of assessing interaction do not adequately consider the life course, and the temporal dynamics through which an individual's sufficient cause is completed. Different individuals may be at different stages of development along the path to disease, but this is not usually measurable. Thus, for example, acquired susceptibility in children can be an important source of variation. 3. A distinction must be made between individual-based and population-level models. Most epidemiologic discussions of causality fail to make this distinction. 4. At the population level, there is additional uncertainty in quantifying interaction and assigning etiologic fractions to different necessary causes because of ignorance about the components of the sufficient cause.

Abstract Background Ragpickers are informal workers who collect recyclable materials to earn a small wage. Their life and working conditions are extremely difficult. We examined minor psychiatric disorders (MPD) among a cohort of ragpickers in Pelotas, a city in southern Brazil. Methods Ragpickers were matched by sex, age, and years of schooling with a sample of non-ragpickers from the same poor neighborhoods. The cross-sectional study gathered data by interview on 990 individuals in 2004. MPD were assessed using a standard self-reporting questionnaire, the SRQ-20. Results The prevalence of MPD among ragpickers was 44.7%, higher than reported by neighborhood controls (33.6%; p < 0.001). MPD were more common among females, those of lower economic level, smokers and alcoholics. Among occupational characteristics, MPD prevalence was associated with frequent static postures, low job satisfaction and recent work accidents. Conclusion Ragpickers more frequently report MPD than other poor workers living in the same neighborhoods, with many of the same life conditions. Improving the work lives of these precarious workers should address not only the physical hazards of their jobs but their mental and emotional health as well.