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RESUMOA afirmação que a produção de café de qualidade é mais cara que a produção de café de menor qualidade, também que mercado falha na transmissão de sinais de qualidade para os produtores baixarem a qualidade média do café produzido. Ao usar equações simultâneas em mínimos quadrados de três estágios, descobriu-se que algumas variáveis foram significantes: o tamanho do produtor afeta a parcela de café cherry vendida, a qualidade afeta o preço internacional de café verde do México, e a qualidade da cherry aumenta a parcela vendida de café verde. Mas, não há evidencia que a concentração de poder de mercado afete a parcela de preços do café verde.ABSTRACTThe assumption that the production of quality coffee is more expensive than the production of coffee of less quality, also that market failures in the transmission of quality signals to producer lower the average quality of coffee produced industry. Used its simultaneous equations in three stage lest square we have found that some variable were significant; the size of the producer affects the share of sold cherry, the quality affects the international green coffee price of México and the quality of cherry increases the share of green coffee sold. But there in no evidence that market power concentration affects the share prices of green coffee.RESUMENSe afirma que producir café de calidad es más caro que producir café de peor calidad, y también que el mercado falla en la transmisión de señales de calidad para que los productores disminuyan la calidad media del café producido. Al usar ecuaciones simultáneas en mínimos cuadrados de tres etapas, se descubrió que algunas variables fueron significativas: el tamaño del productor afecta la fracción de café cherry vendida, la calidad afecta el precio internacional del café verde de México y la calidad de la cherry aumenta la fracción vendida de café verde. Pero no hay evidencia de que la concentración de poder de mercado afecte la fracción de precios del café verde.

BackgroundPublic mass shootings are a significant public health problem that require ongoing systematic surveillance to test and inform policies that combat gun injuries. Although there is widespread agreement that something needs to be done to stop public mass shootings, opinions on exactly which policies that entails vary, such as the prohibition of assault weapons and large-capacity magazines. ObjectiveThe aim of this study was to determine if the Federal Assault Weapons Ban (FAWB) (1994-2004) reduced the number of public mass shootings while it was in place. MethodsWe extracted public mass shooting surveillance data from the Violence Project that matched our inclusion criteria of 4 or more fatalities in a public space during a single event. We performed regression discontinuity analysis, taking advantage of the imposition of the FAWB, which included a prohibition on large-capacity magazines in addition to assault weapons. We estimated a regression model of the 5-year moving average number of public mass shootings per year for the period of 1966 to 2019 controlling for population growth and homicides in general, introduced regression discontinuities in the intercept and a time trend for years coincident with the federal legislation (ie, 1994-2004), and also allowed for a differential effect of the homicide rate during this period. We introduced a second set of trend and intercept discontinuities for post-FAWB years to capture the effects of termination of the policy. We used the regression results to predict what would have happened from 1995 to 2019 had there been no FAWB and also to project what would have happened from 2005 onward had it remained in place. ResultsThe FAWB resulted in a significant decrease in public mass shootings, number of gun deaths, and number of gun injuries. We estimate that the FAWB prevented 11 public mass shootings during the decade the ban was in place. A continuation of the FAWB would have prevented 30 public mass shootings that killed 339 people and injured an additional 1139 people. ConclusionsThis study demonstrates the utility of public health surveillance on gun violence. Surveillance informs policy on whether a ban on assault weapons and large-capacity magazines reduces public mass shootings. As society searches for effective policies to prevent the next mass shooting, we must consider the overwhelming evidence that bans on assault weapons and/or large-capacity magazines work.

BackgroundThe COVID-19 pandemic has disrupted the lives of millions and forced countries to devise public health policies to reduce the pace of transmission. In the Middle East and North Africa (MENA), falling oil prices, disparities in wealth and public health infrastructure, and large refugee populations have significantly increased the disease burden of COVID-19. In light of these exacerbating factors, public health surveillance is particularly necessary to help leaders understand and implement effective disease control policies to reduce SARS-CoV-2 persistence and transmission. ObjectiveThe goal of this study is to provide advanced surveillance metrics, in combination with traditional surveillance, for COVID-19 transmission that account for weekly shifts in the pandemic speed, acceleration, jerk, and persistence to better understand a country’s risk for explosive growth and to better inform those who are managing the pandemic. Existing surveillance coupled with our dynamic metrics of transmission will inform health policy to control the COVID-19 pandemic until an effective vaccine is developed. MethodsUsing a longitudinal trend analysis study design, we extracted 30 days of COVID-19 data from public health registries. We used an empirical difference equation to measure the daily number of cases in MENA as a function of the prior number of cases, the level of testing, and weekly shift variables based on a dynamic panel data model that was estimated using the generalized method of moments approach by implementing the Arellano-Bond estimator in R. ResultsThe regression Wald statistic was significant (χ25=859.5, P