Lead is a neurotoxicant that negatively affects health. Reducing lead exposure and early detection among children are important public health goals. Our objective with this study was to determine if ...the September 2015 lead advisory in Flint, Michigan affected lead testing among children when possible exposure was widely publicized.
This study included 206 001 children born in Michigan from 2013 to 2015 and enrolled in Medicaid, using 2013 to 2017 claims data to determine if and at what age an individual received a lead test. Difference-in-differences regression models were used to compare the receipt of lead tests among children in Flint with other cities in Michigan before and after September 2015, when a lead advisory was issued for the city warning about potential exposure to lead in publicly supplied water.
Before the lead advisory, approximately 50% of children in Flint received a lead test by 12 months of age and nearly 75% received a lead test by 24 months of age. After the September 2015 advisory, the receipt of lead tests among children in Flint increased 10 percentage points by 12 months compared with other cities. Effects by 10-month cohorts, as of 2016, revealed a 20-percentage-point increase for children in Flint compared with other cities.
Despite a highly publicized lead advisory, children in Flint enrolled in Medicaid received lead tests earlier, but the proportion of Medicaid-eligible children who were tested did not change. This suggests that increasing lead testing is a difficult policy goal to achieve and, therefore, supports recent efforts focusing on primary prevention to reduce lead exposure.
Future nuclear arms reduction efforts will require technologies to verify that warheads slated for dismantlement are authentic without revealing any sensitive weapons design information to ...international inspectors. Despite several decades of research, no technology has met these requirements simultaneously. Recent work by Kemp et al. Kemp RS, Danagoulian A, Macdonald RR, Vavrek JR (2016) Proc Natl Acad Sci USA 113:8618–8623 has produced a novel physical cryptographic verification protocol that approaches this treaty verification problem by exploiting the isotope-specific nature of nuclear resonance fluorescence (NRF) measurements to verify the authenticity of a warhead. To protect sensitive information, the NRF signal from the warhead is convolved with that of an encryption foil that contains key warhead isotopes in amounts unknown to the inspector. The convolved spectrum from a candidate warhead is statistically compared against that from an authenticated template warhead to determine whether the candidate itself is authentic. Here we report on recent proof-of-concept warhead verification experiments conducted at the Massachusetts Institute of Technology. Using high-purity germanium (HPGe) detectors, we measured NRF spectra from the interrogation of proxy “genuine” and “hoax” objects by a 2.52 MeV endpoint bremsstrahlung beam. The observed differences in NRF intensities near 2.2 MeV indicate that the physical cryptographic protocol can distinguish between proxy genuine and hoax objects with high confidence in realistic measurement times.
Emergencies, such as natural and manmade disasters, can present an opportunity or be a detriment to preventive healthcare. While stay‐at‐home orders which some states implemented to mitigate the ...impact of COVID‐19 are known to reduce acute and routine care, little is known about missed preventive care. Dental care, unlike other forms of preventive care ‐ such as pediatric vaccines and well‐visits, is simpler to analyze as it is not practicable with telehealth. Using weekly foot traffic data by SafeGraph from January 2018 to June 2020, we examine the effect of stay‐at‐home orders on visits to dental offices, finding a 15.4% decline after March 2020 for states with stay‐at‐home orders. Surprisingly, we find that states which allowed dental care during the stay‐at‐home period experienced a further 7.4% decline in visits. Using Michigan Medicaid dental claims for children we find that the decline of 0.25 claims per month is driven primarily by fewer diagnostic and preventive care visits. Though some preventive visits were rescheduled, we estimate only 58% of visits missed in March and April 2020 were made up by the end of the year. These estimates quantify the short‐term declines in preventive dental care, suggesting similar declines in other preventive care.
Neutron Resonance Transmission Analysis (NRTA) uses resonant absorption of neutrons to infer the absolute isotopic composition of a target object, enabling applications in a broad range of fields ...such as archeology, enrichment analysis of nuclear fuel, and arms control treaty verification. In the past, NRTA involved large user facilities and complex detector systems. However, recent advances in the intensity of compact neutron sources have made compact neutron imaging designs increasingly feasible. This work describes the Monte Carlo (MC) based design of a compact epithermal NRTA radiographic instrument, which uses a moderated, compact deuterium-tritium neutron source and an epithermal neutron detector. Such an instrument would have a wide range of applications and would be especially impactful for scenarios such as nuclear inspection and arms control verification exercises, where system complexity and mobility may be of critical importance. The MC simulations presented in this work demonstrate accurate time-of-flight reconstructions for transmitted neutron energies, capable of differentiating isotopic compositions of nuclear material with high levels of accuracy. A new generation of miniaturized and increasingly more intense neutron sources will allow this technique to achieve measurements with greater precision and speed, with significant impact on a variety of engineering and societal problems.
To characterize the effects of Michigan's controlled substance legislation on acute care prescriber behavior by specialty, in a single hospital system.
A retrospective study of opioid and ...benzodiazepine prescription records from a hospital electronic medical record system between August 1, 2016, and March 31, 2019, in Detroit, Michigan.
Discharges from inpatient and emergency department visits.
Evaluating the impact of implementation of state controlled substance legislation, comparing prescriptions by physicians before, upon, and after June 1, 2018, using regression discontinuity analysis.
Total daily prescriptions of opioids and total daily prescriptions of benzodiazepine by physicians in the hospital system. Prescriptions were converted to morphine and lorazepam equivalents for comparability.
We find 38.5% (95% confidence interval CI : 74.1% - 2.9%) decrease of prescription in milligrams of opioid equivalents attributable to implementation of legislation. The main catalyst of the decrease was emergency medicine which experienced 63.9% (95% CI: 109.7%-18.0%) decrease in milligrams of opioid equivalent prescriptions, while surgery increased prescriptions. Though we do not find any statistically significant changes in prescriptions of milligram equivalent of benzodiazepines, we estimate 43.1% (95% CI: 82.6%-3.7%) decrease in count of these prescriptions, implying a significant increase in average dosage of prescriptions.
The introduction of new regulatory requirements for the prescription of controlled substances led to a general decrease in morphine equivalent milligrams prescribed in most specialties, though it may have increased the dosage of benzodiazepine prescriptions. The change in prescription behavior could be motivated by regulatory hassle or by change in attitude towards opioid prescriptions and increased recognition of opioid use disorder.
The Spin Asymmetries of the Nucleon Experiment measured two double spin asymmetries using a polarized proton target and polarized electron beam at two beam energies, 4.7 and 5.9 GeV. A ...large-acceptance open-configuration detector package identified scattered electrons at 40° and covered a wide range in Bjorken x (0.3<x<0.8). Proportional to an average color Lorentz force, the twist-3 matrix element, dover ˜_{2}^{p}, was extracted from the measured asymmetries at Q^{2} values ranging from 2.0 to 6.0 GeV^{2}. The data display the opposite sign compared to most quark models, including the lattice QCD result, and an unexpected scale dependence. Furthermore, when combined with the neutron data in the same Q^{2} range the results suggest a flavor independent average color Lorentz force.
Nuclear resonance fluorescence (NRF) is a photonuclear interaction that enables highly isotope-specific measurements in both pure and applied physics scenarios. High-accuracy design and analysis of ...NRF measurements in complex geometries is aided by Monte Carlo simulations of photon physics and transport, motivating Jordan and Warren (2007) to develop the G4NRF codebase for NRF simulation in Geant4. In this work, we enhance the physics accuracy of the G4NRF code and perform improved benchmarking simulations. The NRF cross section calculation in G4NRF, previously a Gaussian approximation, has been replaced with a full numerical integration for improved accuracy in thick-target scenarios. A high-accuracy semi-analytical model of expected NRF count rates in a typical NRF measurement is then constructed and compared against G4NRF simulations for both simple homogeneous and more complex heterogeneous geometries. Agreement between rates predicted by the semi-analytical model and G4NRF simulation is found at a level of ∼1% in simple test cases and ∼3% in more realistic scenarios, improving upon the ∼20% level of the initial benchmarking study and establishing a highly-accurate NRF framework for Geant4.
We measure ^{2}H(e,e^{'}p)n cross sections at 4-momentum transfers of Q^{2}=4.5±0.5 (GeV/c)^{2} over a range of neutron recoil momenta p_{r}, reaching up to ∼1.0 GeV/c. We obtain data at fixed ...neutron recoil angles θ_{nq}=35°, 45°, and 75° with respect to the 3-momentum transfer qover →. The new data agree well with previous data, which reached p_{r}∼500 MeV/c. At θ_{nq}=35° and 45°, final state interactions, meson exchange currents, and isobar currents are suppressed and the plane wave impulse approximation provides the dominant cross section contribution. We compare the new data to recent theoretical calculations, where we observe a significant discrepancy for recoil momenta p_{r}>700 MeV/c.
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