Analysis of the Dose Commitments Resulting from Atmospheric Transport and Deposition from Nuclear Risk Sites in the Russian Far East

The purpose of this study was to estimate the worst-case case dose commitments and potential consequences of accidental releases at nuclear risk sites in the Russian Far East. The nuclear risk sites of concern are near Petropavlovsk (52055'N & 158030'E) and Vladivostok (42055'N & 132025'E). The region of interest includes the territories of the Russian Far East, China, Japan, North and South Korea, State of Alaska, the Aleutian Islands, Mongolia, Burma, Hong Kong, Laos, Taiwan, Thailand, and Vietnam. The transboundary region (i.e., that outside of Russia) is of primary interest because the largest doses resulting from hypothetical releases from these sites would reside in Russia and would be examined using site specific information and detailed models that were unavailable for this study. However, the transboundary region can be examined, in general, using existing information and models. The The methodology from the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) 1993 Report was used in this study to estimate effective dose commitments. It is recognized that this methodology is not the only acceptable manner to estimate such doses; the methodology was selected because it is independent, defensible, and, because it is based upon a multiplicative model, lends itself to a facile examination of parameter variation. The research tool used to generate the deposition data used as the basis of this study was a long-range transport model - the Danish Emergency Response Model of the Atmosphere (DERMA) which was used to simulate the 5-d atmospheric transport, dispersion and deposition of Cs-137 for a one-day release at a rate of 10Bq s-1 for a total "unit hypothetical release" of 8.64x10 14 Bq. The meteorological data from the European Center for Medium- Range Weather Forecasts (ECMWF, Reading, UK) based on the ECMWF global model forecast and analysis were used as input data for the model simulation. Using the DERMA model, the total Cs-137 depositions (i.e., sums of pertinent dry and wet deposition values) were computed for over 90% of the days in calendar year 2000. The necessary meteorological data was missing for the remaining days. In this report, Sr-90 and I-131 were radionuclides that might also have been of concern depending upon the conditions of the study. However, because of a lack of time and resources, the deposition values were not computed for these radionuclides for all calendar year 2000 days. There were Sr-90 and I-131 concentration and deposition data provided for selected days that were considered representative of the variation of the climactic condtions for the region for the year 2000. These data were used to generate simple, linear linear relationships between the unavailable Sr-90 and I-131 concentration and deposition data and the corresponding Cs-137 data. These relationships were found to be sufficiently accurate for the general examination undertaken in this report and were used to generate the necessary, unavailable data. From an examination of the appropriate source term information and deposition to dose transfer factors from both the UNSCEAR 1993 Report and the worst-case scenario, Cs-137 was determined to be the radionuclide of primary concern for this study. The Cs-137 deposition- to-dose transfer factor was dominated by the external exposure (to ground deposition) pathway. For the Petropavlovsk nuclear risk site, the maximum Cs-137 total deposition (locates in Russia) translated into a worst-case maximum effective dose commitment of 108 mSv per person for the maximum exposed individual (i.e., teen). For the transboundary region (i.e., that area outside of Russia), the maximum effective dose commitment was 5.0 mSv per teen. This maximum value was located in the State of Alaska; the maximum effective dose commitment for the Aleutian Islands was 3.3 mSv per teen. The maximum effective dose commitments in the effected U.S. territories were generally three to four times higher than those in Japan, the transboundary country with the next highest maximum dose commitments resulting from accidental releases from the Petropavlovsk risk site. For the Vladivostok nuclear risk site, the maximum Cs-137 137 total deposition (located again in Russia) translated into a worst-case maximum effective dose commitment of 102 mSv per teen. For the transboundary region, the maximum effective dose commitment for Cs-137 was 27 mSv per teen. These maximum values were located in China, which is proximate to the Vladivostok site. The maximum effective dose commitments for Japan and N. Korea are approximately the same (i.e., within a factor of two) as that for China. Note that the maximum effective dose commitments in the U.S. territories are generally more than a factor of 60 lower than those in China, the transboundary country with the highest maximum dose commitments resulting from accidental releases from the Vladivostok risk site. The maximum worst-case dose commitments corresponding to the potential Petropavlovsk and Vladivostok releases for both the regional and transboundary conditions were also compared to various annual reference levels (i.e., 0.15, 1.0, 10, and 100 mSv per person) discussed in the International Commission on Radiological Protection (ICRP) 82 Report pertaining to practices and interventions and the annual background radiation dose (i.e., 2.4 mSv per person) provided in the UNSCEAR 1993 Report. These comparisons were conservative because the effective dose commitments computed in this report are being compared to annual reference values and background doses. The worst-case maximum dose commitments from the Petropavlovsk site for the transboundary region on over 99% of all year 2000 days studied are less than the average annual background radiation dose. For the Vladivostok releases, the worst-case maximum dose commitments are less than the average annual background radiation dose for more than 44% of all year 2000 days studied. Furthermore, the maximum dose commitments corresponding to the Vladivostok releases for more than 90% of the year 2000 days studied are less than the annual 10 mSv per person level in which interventions are rarely justified and are all less than the annual 100 mSv per person level in which interventions are almost always justifiable according to ICRP 82. Therefore, the impacts from the adjusted Vladivostok releases would be, in general, more significant than those from Petropavlovsk (even though the Petropavlovsk releases translate into the maximum, worst-case dose commitment). The more significant impacts of the potential Vladivostok releases were compounded by the fact that many more people were impacted than from the corresponding hypothetical Petropavlovsk releases. However, the dose commitments from the potential Vladivostok releases could be considered negligible when compared to the 10 mSv per person level in which interventions are rarely justified. The maximum collective dose commitments corresponding to the worst-case dose commitments were also computed. The results indicate that even though the maximum effective dose commitments from the Petropavlovsk and Vladivostok releases were similar, the larger populations impacted by the Vladivostok releases generally resulted in significantly larger collective dose commitments and thus potential mortalities than those for the Petropavlovsk releases. For example, the maximum number of additional mortalities on a regional basis resulting from the worst-case Petropavlovsk scenario would be 355 with as many as 329 in Japan, 83 in China, 18 in the State of Alaska, and 10 in S. Korea. However, for the Vladivostok releases, there could be as many as 9771 additional mortalities on a regional basis, and the additional mortalities for Japan, China, N. Korea, S. Korea, Russia, and Taiwan would be 9501, 8575, 2485, 2436, 1614, and 318, respectively. The U.S. territories and Hong Kong might have an additional two mortalities each. However, even though these mortality numbers may appear large, it should be noted that none of the transboundary values exceed 9 mortalities per 100 000 persons, which is found in N. Korea resulting from the worst-case Vladivostok scenario. Because the aggregation of doses over large areas is contrary to the recommendation of the ICRP, a series of threshold values were imposed on the worst-case results to determine whether the conclusions would change dramatically. The impact on the maximum worst-case collective dose commitments for the Petropavlovsk releases would be significan. For example, if a threshold of 1 mSv per person is imposed on the collective dose computation, then the collective dose commitment for all transboundary areas except for the U.S. territories falls to zero (and this includes Japan, which had the largest collective dose commitment). However, the impact of imposing such thresholds on the collective dose commitments from the Vladivostok releases was much less profound than that for the corresponding Petropavlovsk dose commitments; in fact, the imposition of thresholds up to 1 mSv per person had little impact on the collective dose commitments for most countries in the region of interest. Even though the impact on the collective doses related to the Vladivostok releases was small, it remains true that the worst-case impacts of the effective dose commitments for the releases from both the Vladivostok and Petropavlovsk sites were negligible when compared to metrics such as the average annual background dose and other causes of death in the affected countries

Spontaneous decay in the presence of dispersing and absorbing bodies: general theory and application to a spherical cavity

A formalism for studying spontaneous decay of an excited two-level atom in the presence of dispersing and absorbing dielectric bodies is developed. An integral equation, which is suitable for numerical solution, is derived for the atomic upper-state-probability amplitude. The emission pattern and the power spectrum of the emitted light are expressed in terms of the Green tensor of the dielectric-matter formation including absorption and dispersion. The theory is applied to the spontaneous decay of an excited atom at the center of a three-layered spherical cavity, with the cavity wall being modeled by a band-gap dielectric of Lorentz type. Both weak coupling and strong coupling are studied, the latter with special emphasis on the cases where the atomic transition is (i) in the normal-dispersion zone near the medium resonance and (ii) in the anomalous-dispersion zone associated with the band gap. In a single-resonance approximation, conditions of the appearance of Rabi oscillations and closed solutions to the evolution of the atomic state population are derived, which are in good agreement with the exact numerical results.Comment: 12 pages, 6 figures, typos fixed, 1 figure adde

A dynamical model of lipoprotein metabolism

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Equivalence of 2 effective graft-versus-host disease prophylaxis regimens: Results of a prospective double-blind randomized trial

AbstractWe have previously demonstrated a decrease in the incidence of acute graft-versus-host disease (GVHD) with the addition of methotrexate (MTX) to cyclosporine (CSP) and prednisone (PSE) chemotherapy in patients with leukemia. We have now completed a prospective randomized trial comparing the 3-drug regimen (CSP/MTX/PSE, including 3 doses of MTX) to the standard 2-drug regimen (CSP/MTX, including 4 doses of MTX) to investigate the benefit of PSE used up front for the prevention of acute and chronic GVHD. In the trial, 193 patients were randomized and 186 were included in the final analysis. All patients received a bone marrow graft from a fully histocompatible sibling donor. The preparatory regimen consisted of fractionated total-body irradiation (fTBI) and etoposide in all but 13 patients, who received fTBI and cyclophosphamide. The patients were randomized to receive either CSP/MTX/PSE or CSP/MTX. The 2 groups were well balanced with respect to diagnosis, disease stage, age, donor-recipient sex, and parity. In an intent-to-treat analysis, the incidence of acute GVHD was 18% (95% confidence interval [CI] 12-28) for the CSP/MTX/PSE group compared with 20% (CI 10-26) for the CSP/,MTX group (P = .60), with a median follow up of 2.2 years. Overall survival was 65% for those receiving CSP/MTX/PSE and 72% for those receiving CSP/MTX (P = .10); the relapse rate was 15% for the CSP/MTX/PSE group and 12% for the CSP/MTX group (P = .83). The incidence of chronic GVHD was similar (46% versus 52%; P = .38), with a follow-up of 0.7 to 6.0 years. Of interest, 21 patients went off study due to GVHD (5 in the CSP/MTX/PSE group and 16 in the CSP/MITX group [P = .02]), and 11 patients went off study because of alveolar hemorrhage (3 in the CSP/MTX/PSE group and 8 in the CSP/MTX group [P = .22]). The addition of PSE did not result in a higher incidence of infectious complications, bacterial (66% versus 58%), viral (77% versus 66%), or fungal (20% versus 20%), in those receiving CSP/MTX/PSE versus CSP/MTX, respectively. These data suggest that the addition of PSE was associated with a somewhat lower incidence of early posttransplantation complications but did not have a positive impact on the incidence of acute or chronic GVHD or event-free or overall survival.Biol Blood Marrow Transplant 2000;6(3):254-61

Modeling the Subsurface Structure of Sunspots

While sunspots are easily observed at the solar surface, determining their subsurface structure is not trivial. There are two main hypotheses for the subsurface structure of sunspots: the monolithic model and the cluster model. Local helioseismology is the only means by which we can investigate subphotospheric structure. However, as current linear inversion techniques do not yet allow helioseismology to probe the internal structure with sufficient confidence to distinguish between the monolith and cluster models, the development of physically realistic sunspot models are a priority for helioseismologists. This is because they are not only important indicators of the variety of physical effects that may influence helioseismic inferences in active regions, but they also enable detailed assessments of the validity of helioseismic interpretations through numerical forward modeling. In this paper, we provide a critical review of the existing sunspot models and an overview of numerical methods employed to model wave propagation through model sunspots. We then carry out an helioseismic analysis of the sunspot in Active Region 9787 and address the serious inconsistencies uncovered by \citeauthor{gizonetal2009}~(\citeyear{gizonetal2009,gizonetal2009a}). We find that this sunspot is most probably associated with a shallow, positive wave-speed perturbation (unlike the traditional two-layer model) and that travel-time measurements are consistent with a horizontal outflow in the surrounding moat.Comment: 73 pages, 19 figures, accepted by Solar Physic

Incidence and Prevalence of Incarceration in a Longitudinal Cohort of Women at Risk for Human Immunodeficiency Virus in the United States, 2007-2017

Background: To estimate the incidence, prevalence, frequency, and duration of incarceration and to identify risk factors for incarceration among women at risk for human immunodeficiency virus (HIV) in the United States. Methods: During semiannual study visits in a multicenter cohort study, 970 HIV sero-negative participants at risk for HIV were asked about their own incarceration (10/2007-09/2017) and incarceration of sexual partners (10/2013-09/2017). We used descriptive statistics and multivariable log-binomial regression to identify baseline predictors of incident incarceration. Results: Median follow-up time across the 970 participants was 5.5 years (IQR 3.5-9.5). Nearly half (n = 453, 46.7%) of participants were incarcerated during or before the study, and the incarceration rate was 5.5 per 100 person-years. In multivariable models, incident incarceration was associated with prior incarceration (RR 5.20, 95% CI: 3.23-8.41) and noninjection drug use (RR 1.57, 95% CI: 1.10-2.25). Conclusions: Incarceration is common for women at risk for HIV. Prevention interventions that address the complex interplay of drug use, sex exchange, and housing instability for women who have experienced incarceration have the potential to reach an important group of U.S. women at risk of HIV infection

Incarceration and Number of Sexual Partners after Incarceration among Vulnerable US Women, 2007-2017

Objectives. To examine whether women's incarceration increases numbers of total and new sexual partners. Methods. US women with or at risk for HIV in a multicenter cohort study answered incarceration and sexual partner questions semiannually between 2007 and 2017. We used marginal structural models to compare total and new partners at visits not following incarceration with all visits following incarceration and visits immediately following incarceration. Covariates included demographics, HIV status, sex exchange, drug or alcohol use, and housing instability. Results. Of the 3180 participants, 155 were incarcerated. Women reported 2 partners, 3 or more partners, and new partners at 5.2%, 5.2%, and 9.3% of visits, respectively. Relative to visits not occurring after incarceration, odds ratios were 2.41 (95% confidence interval [CI] = 1.20, 4.85) for 2 partners, 2.03 (95% CI = 0.97, 4.26) for 3 or more partners, and 3.24 (95% CI = 1.69, 6.22) for new partners at visits immediately after incarceration. Odds ratios were similar for all visits following incarceration. Conclusions. Women had more total partners and new partners immediately and at all visits following incarceration after confounders and loss to follow-up had been taken into account

Multiwavelength studies of MHD waves in the solar chromosphere: An overview of recent results

The chromosphere is a thin layer of the solar atmosphere that bridges the relatively cool photosphere and the intensely heated transition region and corona. Compressible and incompressible waves propagating through the chromosphere can supply significant amounts of energy to the interface region and corona. In recent years an abundance of high-resolution observations from state-of-the-art facilities have provided new and exciting ways of disentangling the characteristics of oscillatory phenomena propagating through the dynamic chromosphere. Coupled with rapid advancements in magnetohydrodynamic wave theory, we are now in an ideal position to thoroughly investigate the role waves play in supplying energy to sustain chromospheric and coronal heating. Here, we review the recent progress made in characterising, categorising and interpreting oscillations manifesting in the solar chromosphere, with an impetus placed on their intrinsic energetics.Comment: 48 pages, 25 figures, accepted into Space Science Review