Guidance for Decision

The International Institute for Applied Systems Analysis is preparing a "Handbook of Systems Analysis," which will appear in three volumes: Volume 1, "Overview," is aimed at a widely varied audience of producers and users of systems analysis; Volume 2, "Methods," is aimed at systems analysts who need basic knowledge of methods in which they are not expert; the volume contains introductory overviews of such methods; Volume 3, "Cases," contains descriptions of actual systems analyses that illustrate the methods and diversity of systems analysis. Volume 1 will have ten chapters: 1) The context, nature, and use of systems analysis; 2) Applied systems analysis: a genetic approach; 3) Examples of systems analysis; 4) The method of applied systems analysis: finding a solution; 5) Formulating problems for systems analysis; 6) Generating alternatives for systems analysis; 7) Estimating and predicting consequences; 8) Guidance for decision; 9) Implementation; 10) Principles of good practice. To these ten chapters will be added a glossary of systems analysis terms and a bibliography of basic books in the field. This Working Paper is the current draft of Chapter 8. A word about the format of this Working Paper. In order to make the text of each chapter easily amended, it has been entered into the IIASA computer, from which the current version can be reproduced in a few minute's time whenever needed. This Working Paper was produced from the version current on the date shown on each page

Handbook of Systems Analysis: Volume 1. Overview. Chapter 8. Guidance for Decision

The International Institute for Applied Systems Analysis is preparing a Handbook of Systems Analysis, which will appear in three volumes: Volume 1: Overview is aimed at a widely varied audience of producers and users of systems analysis studies. Volume 2: Methods is aimed at systems analysts and other members of systems analysis teams who need basic knowledge of methods in which they are not expert; this volume contains introductory overviews of such methods. Volume 3: Cases contains descriptions of actual systems analyses that illustrate the diversity of the contexts and methods of systems analysis. Drafts of the material for Volume 1 are being widely circulated for comment and suggested improvement. This Working Paper is the current draft of Chapter 8. Correspondence is invited. Volume 1 will consist of the following ten chapters: 1. The context, nature, and use of systems analysis 2. The genesis of applied systems analysis; 3. Examples of applied systems analysis 4. The methods of applied systems analysis: An introduction and overview 5. Formulating problems for systems analysis 6. Objectives, constraints, and alternatives 7. Predicting the consequences: Models and modeling 8. Guidance for decision 9. Implementation 10. The practice of applied systems analysis To these ten chapters will be added a glossary of systems analysis terms and a bibliography of basic works in the field

Composability in quantum cryptography

In this article, we review several aspects of composability in the context of quantum cryptography. The first part is devoted to key distribution. We discuss the security criteria that a quantum key distribution protocol must fulfill to allow its safe use within a larger security application (e.g., for secure message transmission). To illustrate the practical use of composability, we show how to generate a continuous key stream by sequentially composing rounds of a quantum key distribution protocol. In a second part, we take a more general point of view, which is necessary for the study of cryptographic situations involving, for example, mutually distrustful parties. We explain the universal composability framework and state the composition theorem which guarantees that secure protocols can securely be composed to larger applicationsComment: 18 pages, 2 figure

Di-Isocyanate Crosslinked Aerogels with 1, 6-Bis (Trimethoxysilyl) Hexane Incorporated in Silica Backbone

Silica aerogels are desirable materials for many applications that take advantage of their light weight and low thermal conductivity. Addition of a conformal polymer coating which bonds with the amine decorated surface of the silica network improves the strength of the aerogels by as much as 200 times. Even with vast improvement in strength they still tend to undergo brittle failure due to the rigid silica backbone. We hope to increase the flexibility and elastic recovery of the silica based aerogel by altering the silica back-bone by incorporation of more flexible hexane links. To this end, we investigated the use of 1,6-bis(trimethoxysilyl)hexane (BTMSH), a polysilsesquioxane precursor3, as an additional co-reactant to prepare silica gels which were subsequently cross-linked with di-isocyanate. Previously, this approach of adding flexibility by BTMSH incorporation was demonstrated with styrene cross-linked aerogels. In our study, we varied silane concentration, mol % of silicon from BTMSH and di-isocyanate concentration by weight percent to attempt to optimize both the flexibility and the strength of the aerogels

Attacks on quantum key distribution protocols that employ non-ITS authentication

We demonstrate how adversaries with unbounded computing resources can break Quantum Key Distribution (QKD) protocols which employ a particular message authentication code suggested previously. This authentication code, featuring low key consumption, is not Information-Theoretically Secure (ITS) since for each message the eavesdropper has intercepted she is able to send a different message from a set of messages that she can calculate by finding collisions of a cryptographic hash function. However, when this authentication code was introduced it was shown to prevent straightforward Man-In-The-Middle (MITM) attacks against QKD protocols. In this paper, we prove that the set of messages that collide with any given message under this authentication code contains with high probability a message that has small Hamming distance to any other given message. Based on this fact we present extended MITM attacks against different versions of BB84 QKD protocols using the addressed authentication code; for three protocols we describe every single action taken by the adversary. For all protocols the adversary can obtain complete knowledge of the key, and for most protocols her success probability in doing so approaches unity. Since the attacks work against all authentication methods which allow to calculate colliding messages, the underlying building blocks of the presented attacks expose the potential pitfalls arising as a consequence of non-ITS authentication in QKD-postprocessing. We propose countermeasures, increasing the eavesdroppers demand for computational power, and also prove necessary and sufficient conditions for upgrading the discussed authentication code to the ITS level.Comment: 34 page

Increased synthesis of phosphatidylcholine by rat lung following premature birth

Pregnant rats were delivered prematurely at 20 days and 21 days gestation (2 and 1 day premature). The survival was 52 +/- 3% at 20 days gestation and 100% at 21 days gestation. [Me-14C]Choline incorporation into phosphatidylcholine increased by 60% during the 3 h of survival after delivery at 20 days gestation. The increase in incorporation occurred during the first hour of survival. [Me-14C]Choline incorporation also increased to a lesser extent following survival at 21 days gestation. The incorporation after 3 h of survival at 20 days and 21 days gestation was similar to that obtained with adult lung slices. The incorporation of [U-14C]glycerol, -[U-14C]glucose, [1-14C]palmitate and [1,2-14C]-ethanolamine did not increase following delivery at either 20 days or 21 days gestation. The incorporation of 33PO4 into phosphatidylcholine increased to the same relative extent as [Me-14C]choline incorporation. -[U-14C]Glucose incorporation into the fatty acid portion of phosphatidylcholine and triacyl-glycerols and oxidation to 14CO2 decreased during the 3 h of survival. The pattern of -[U-14C]glucose incorporation following survival at 20 and 21 days gestation is similar to that obtained with adult lung slices. Dexamethasone treatment of mothers at 17 and 18 days gestation caused [Me-14C]choline incorporation to increase to adult values at 20 days gestation but not at 19 days or 21 days. We conclude that an adaptive mechanism exists which produces specific biochemical changes in lung metabolism following premature birth. This mechanism is functional in the rat as early as 2 days prior to normal term.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23337/1/0000277.pd

Impact Ionization in ZnS

The impact ionization rate and its orientation dependence in k space is calculated for ZnS. The numerical results indicate a strong correlation to the band structure. The use of a q-dependent screening function for the Coulomb interaction between conduction and valence electrons is found to be essential. A simple fit formula is presented for easy calculation of the energy dependent transition rate.Comment: 9 pages LaTeX file, 3 EPS-figures (use psfig.sty), accepted for publication in PRB as brief Report (LaTeX source replaces raw-postscript file

Preparation, analysis, and application of coated glass targets for the Wendelstein 7-X laser blow-off system

Coated glass targets are a key component of the Wendelstein 7-X laser blow-off system that is used for impurity transport studies. The preparation and analysis of these glass targets as well as their performance is examined in this paper. The glass targets have a high laser damage threshold and are coated via physical vapor deposition with μm thick films. In addition, nm-thin layers of Ti are used as an interface layer for improved ablation efficiency and reduced coating stress. Hence, the metallic or ceramic coating has a lateral homogeneity within 2% and contaminants less than 5%, being optimal for laser ablation processing. With this method, a short (few ms) and well defined pulse of impurities with about 1017 particles can be injected close to the last closed flux surface of Wendelstein 7-X. In particular, a significant amount of atoms with a velocity of about 1 km/s enters the plasma within 1 ms. The atoms are followed by a negligible concentration of slower clusters and macro-particles. This qualifies the use of the targets and applied laser settings for impurity transport studies with the laser blow-off system in Wendelstein 7-X. © 2020 Author(s)

Association Between COVID-19 and Mortality in Hip Fracture Surgery in the National COVID Cohort Collaborative (N3C): A Retrospective Cohort Study

BACKGROUND: This study investigated the outcomes of coronavirus disease (COVID-19)-positive patients undergoing hip fracture surgery using a national database. METHODS: This is a retrospective cohort study comparing hip fracture surgery outcomes between COVID-19 positive and negative matched cohorts from 46 sites in the United States. Patients aged 65 and older with hip fracture surgery between March 15 and December 31, 2020, were included. The main outcomes were 30-day all-cause mortality and all-cause mortality. RESULTS: In this national study that included 3303 adults with hip fracture surgery, the 30-day mortality was 14.6% with COVID-19-positive versus 3.8% in COVID-19-negative, a notable difference. The all-cause mortality for hip fracture surgery was 27.0% in the COVID-19-positive group during the study period. DICUSSION: We found higher incidence of all-cause mortality in patients with versus without diagnosis of COVID-19 after undergoing hip fracture surgery. The mortality in hip fracture surgery in this national analysis was lower than other local and regional reports. The medical community can use this information to guide the management of hip fracture patients with a diagnosis of COVID-19