Multiple scattering by a collection of randomly located obstacles Part II: Numerical implementation - coherent fields

A numerical implementation of a rigorous theory to analyze scattering by randomly located obstacles is presented. In general, the obstacles can be of quite arbitrary shape, but, in this first implementation, the obstacles are dielectric spheres. The coherent part of the reflected and transmitted intensity at normal incidence is treated. Excellent agreement with numerical results found in the literature of the effective wave number is obtained. Moreover, comparisons with the results of the Radiative Transfer Equation (RTE) are made. The present theory also gives a small reflected coherent field, which is not predicted by the RTE, and these results are discussed in some detail

Multiple scattering by a collection of randomly located obstacles Part IV: The effect of the pair correlation function

The effect of two different pair correlation functions, used to model multiple scattering in a slab filled with randomly located spherical particles, is investigated. Specifically, the Percus-Yevick approximation is employed and a comparison with the simple hole correction is made. The kernel entries of the hole correction have an analytic solution, which makes the numerical solution of the integral equations possible. The kernel entries of Percus-Yevick approximation are integrated numerically after a subtraction of the slowly converging part in the integrand. Several numerical examples illustrate the effect of the two pair correlation functions, and we also make a comparison with the predictions Bouguer-Beer law gives

Severity as a Priority Setting Criterion: Setting a Challenging Research Agenda

Priority setting in health care is ubiquitous and health authorities are increasingly recognising the need for priority setting guidelines to ensure efficient, fair, and equitable resource allocation. While cost-effectiveness concerns seem to dominate many policies, the tension between utilitarian and deontological concerns is salient to many, and various severity criteria appear to fill this gap. Severity, then, must be subjected to rigorous ethical and philosophical analysis. Here we first give a brief history of the path to today’s severity criteria in Norway and Sweden. The Scandinavian perspective on severity might be conducive to the international discussion, given its long-standing use as a priority setting criterion, despite having reached rather different conclusions so far. We then argue that severity can be viewed as a multidimensional concept, drawing on accounts of need, urgency, fairness, duty to save lives, and human dignity. Such concerns will often be relative to local mores, and the weighting placed on the various dimensions cannot be expected to be fixed. Thirdly, we present what we think are the most pertinent questions to answer about severity in order to facilitate decision making in the coming years of increased scarcity, and to further the understanding of underlying assumptions and values that go into these decisions. We conclude that severity is poorly understood, and that the topic needs substantial further inquiry; thus we hope this article may set a challenging and important research agenda

Moral Stress among Swedish Health Care Workers During the COVID-19 Pandemic: A Cross-Sectional Study

Aims: This study quantifies to what extent Health care workers (HCWs) experienced moral stress and to what extent their experiences of moral stress were related to gender and age as well as to working directly with COVID-19 patients and other work-related factors. Methods: This study consists of a cross-sectional survey that was conducted among 16,044 Swedish HCWs. A total of 153,300 HCWs and support staff who participated in the COVID-19 training offered by the Karolinska Institute were invited by email to participate in a web survey during autumn 2020. Results: This study is the first to quantify the frequency and severity of moral stress in a large group of HCWs. Moral stress was reported to a higher extent by HCWs involved in COVID-19 care and those involved in direct patient care. A lack of resources and the restrictions that hindered the patients’ family and friends from being involved were major causes of moral stress. Informal support was reported as being the most available and useful for dealing with moral stress. Conclusions: Our findings suggest that moral stress is common among HCWs who work with infected patients during a pandemic. The goal should not be to eliminate moral stress, as such stress may be viewed as a normal reaction to moral issues, but organizational structures (sufficient staffing and resources), could decrease the likelihood of morally stressful situations. Finally, to avoid the development of moral distress and its potential consequences, improvements could be made in providing HCWs with support tools for managing moral stress