A technique for pediatric total skin electron irradiation

<p>Abstract</p> <p>Background</p> <p>Total skin electron irradiation (TSEI) is a special radiotherapy technique which has generally been used for treating adult patients with mycosis fungoides. Recently, two infants presented with leukemia cutis isolated to the skin requiring TSEI. This work discusses the commissioning and quality assurance (QA) methods for implementing a modified Stanford technique using a rotating harness system to position sedated pediatric patients treated with electrons to the total skin.</p> <p>Methods and Results</p> <p>Commissioning of pediatric TSEI consisted of absolute calibration, measurement of dosimetric parameters, and subsequent verification in a pediatric patient sized cylindrical phantom using radiographic film and optically stimulated luminance (OSL) dosimeters. The depth of dose penetration under TSEI treatment condition was evaluated using radiographic film sandwiched in the phantom and demonstrated a 2 cm penetration depth with the maximum dose located at the phantom surface. Dosimetry measurements on the cylindrical phantom and in-vivo measurements from the patients suggested that, the factor relating the skin and calibration point doses (i.e., the <it>B</it>-factor) was larger for the pediatric TSEI treatments as compared to adult TSEI treatments. Custom made equipment, including a rotating plate and harness, was fabricated and added to a standard total body irradiation stand and tested to facilitate patient setup under sedated condition. A pediatric TSEI QA program, consisting of daily output, energy, flatness, and symmetry measurements as well as in-vivo dosimetry verification for the first cycle was developed. With a long interval between pediatric TSEI cases, absolute dosimetry was also repeated as part of the QA program. In-vivo dosimetry for the first two infants showed that a dose of ± 10% of the prescription dose can be achieved over the entire patient body.</p> <p>Conclusion</p> <p>Though pediatric leukemia cutis and the subsequent need for TSEI are rare, the ability to commission the technique on a modified TBI stand is appealing for clinical implementation and has been successfully used for the treatment of two pediatric patients at our institution.</p

SNAPSHOT USA 2019 : a coordinated national camera trap survey of the United States

This article is protected by copyright. All rights reserved.With the accelerating pace of global change, it is imperative that we obtain rapid inventories of the status and distribution of wildlife for ecological inferences and conservation planning. To address this challenge, we launched the SNAPSHOT USA project, a collaborative survey of terrestrial wildlife populations using camera traps across the United States. For our first annual survey, we compiled data across all 50 states during a 14-week period (17 August - 24 November of 2019). We sampled wildlife at 1509 camera trap sites from 110 camera trap arrays covering 12 different ecoregions across four development zones. This effort resulted in 166,036 unique detections of 83 species of mammals and 17 species of birds. All images were processed through the Smithsonian's eMammal camera trap data repository and included an expert review phase to ensure taxonomic accuracy of data, resulting in each picture being reviewed at least twice. The results represent a timely and standardized camera trap survey of the USA. All of the 2019 survey data are made available herein. We are currently repeating surveys in fall 2020, opening up the opportunity to other institutions and cooperators to expand coverage of all the urban-wild gradients and ecophysiographic regions of the country. Future data will be available as the database is updated at eMammal.si.edu/snapshot-usa, as well as future data paper submissions. These data will be useful for local and macroecological research including the examination of community assembly, effects of environmental and anthropogenic landscape variables, effects of fragmentation and extinction debt dynamics, as well as species-specific population dynamics and conservation action plans. There are no copyright restrictions; please cite this paper when using the data for publication.Publisher PDFPeer reviewe

An identified systemic model of the democracy-peace nexus

In previous empirical work, the basis for the proposition that democratic countries do not fight each other has been a single equation regression of hostility on democracy and other variables. This approach is misleading for two reasons. First, peace and democracy are part of a simultaneous system of relations in which they foster each other. Before quantitative inferences which affect policy conclusions can be reached, a separate structural equation has to be estimated corresponding to each of these variables. The equations must be distinguishable from one another at the same time as they embody the interdependence between peace and democracy. Second, previous regression studies emphasized the statistical association between democracy and peace rather than focusing on the substantive magnitude of that effect. To demonstrate the sensitivity of the results to these concerns, we accepted the data and indexes of one of the most influential statements of the peace-democracy thesis, and studied the Cold War period where it is deemed strongest. We differed from the prevailing paradigm by estimating an identified, simultaneous two-equation interactive system. In this more properly specified model, the dyadic democracy-peace nexus generally was not statistically significant and, more important, was very small in its impact. The alternative, peace causing democracy, was much stronger. Neither equation in the simultaneous system explained more than six per cent of the variance, so that other factors are likely to be much more important. Deterrence of aggression and patient negotiation of differences may be a more important guide to public policy than attempts to export western, democratic institutions to other nations. The analysis of these data show that it is more likely that the most important differences that arise between nations are specific to historic epochs and their political and socio-economic conjunctures. Various other indices have been suggested for conflict and democracy in the literature, as well as numerous modifications of the additional variables to be included in the regression equations. The results have tended to be variable with respect to these modifications, but the failure of single equation model specifications to deal with the problem of simultaneous causation makes their results subject to our fundamental methodological criticism and unable to support the burden of policy recommendations.Democracy, Peace, Empirical tests,