The Influence of Organization and Management on the Safety of NPPS and Other Complex Industrial Systems (Report of an IAEA/IIASA consultants meeting in Laxenburg and Vienna, 18-22 March 1991)

An analysis of causes for human errors reveals that deficiencies in organization and management often provide an environment making errors more likely. There is also a considerable difference between the operational performance of similar industrial plants. A closer analysis often reveals that the differences can be attributed to the managing practices. Accepting organization and management as one important precursor for operational safety, the aim is to identify good managerial structures and practices as well as characteristics of unsafe operational practices. Such information can provide guidance for the operators of the installations and also support regulatory agencies. The ultimate aim should be to detect and correct organizational deficiencies before an incident or accident brings them into the open. It is therefore not sufficient to blame individuals nor training, because management and organization establishes priorities, structures, and practices that enable tasks to be accomplished. A consultants' meeting organized jointly by the International Atomic Energy Agency (IAEA) and the International Institute for Applied Systems Analysis (IIASA) was held in Laxenburg and Vienna, Austria on 18-22 March 1991. The objective of the meeting was to assess the extent to which research within the management sciences -can provide guidance for the practical problems of managing organizations, where safety is the major concern. The influence of organization and management on the safety of complex industrial installations was discussed during the meeting and the exchange of ideas and experience between different industrial sectors and the academia proved fruitful. In spite of the difference among national and company practices it is still expected that there are many possibilities for an exchange of good managerial knowledge, experience, and practices. The report collects both the contributions offered by members of the Expert Task Force and the findings of the discussions that took place during the meeting. Specific reference is in the following text made to the nuclear industry with the understanding that the issues have a wider application to chemical plants, off-shore installations or more generally to industries where safety is a major concern

Enhancement of laser-driven ion acceleration in non-periodic nanostructured targets

Using particle-in-cell simulations, we demonstrate an improvement of the target normal sheath acceleration (TNSA) of protons in non-periodically nanostructured targets with micron-scale thickness. Compared to standard flat foils, an increase in the proton cutoff energy by up to a factor of two is observed in foils coated with nanocones or perforated with nanoholes. The latter nano-perforated foils yield the highest enhancement, which we show to be robust over a broad range of foil thicknesses and hole diameters. The improvement of TNSA performance results from more efficient hot-electron generation, caused by a more complex laser-electron interaction geometry and increased effective interaction area and duration. We show that TNSA is optimized for a nanohole distribution of relatively low areal density and that is not required to be periodic, thus relaxing the manufacturing constraints.Comment: 11 pages, 8 figure

Surveillance of Echinococcus multilocularis in rodents in the vicinity of the finding of the first infected red fox (Vulpes vulpes) in Sweden

Olsson, G.E., Hörnfeldt, B., Ågren, E., Wahlström, H

On Weighted Graph Separation Problems and Flow-Augmentation

One of the first application of the recently introduced technique of\emph{flow-augmentation} [Kim et al., STOC 2022] is a fixed-parameter algorithmfor the weighted version of \textsc{Directed Feedback Vertex Set}, a landmarkproblem in parameterized complexity. In this note we explore applicability offlow-augmentation to other weighted graph separation problems parameterized bythe size of the cutset. We show the following. -- In weighted undirected graphs\textsc{Multicut} is FPT, both in the edge- and vertex-deletion version. -- Theweighted version of \textsc{Group Feedback Vertex Set} is FPT, even with anoracle access to group operations. -- The weighted version of \textsc{DirectedSubset Feedback Vertex Set} is FPT. Our study reveals \textsc{DirectedSymmetric Multicut} as the next important graph separation problem whoseparameterized complexity remains unknown, even in the unweighted setting.<br

Time-resolved x-ray spectroscopy of optical-field-ionized plasmas

The time-dependent soft X-ray emission of helium and nitrogen plasmas generated by optical-field ionization is reported. The experiments were carried out by focusing pulses of the high-power Ti:sapphire laser of the Lund Institute of Technology (lambda = 796 nm, pulse duration 150 fs, pulse energy 150 mJ) to a 50-mu m diameter spot close to a nozzle, using He and N-2 as target gases. The emission on He+, N4+, and N3+ resonance lines was recorded by means of a flat-field grating spectrometer coupled to an X-ray streak camera. A pronounced difference in the temporal shape of the emission of the Lyman-alpha line of hydrogen-like helium and of the 2p-3d resonance lines of lithium-like and beryllium-like nitrogen was observed. The helium line exhibited an initial spike followed by a slow revival of the emission, whereas the nitrogen lines showed a slow decay after a fast initial rise. These observations are explained with the help of simulations

Two-color Time-resolved Spectroscopy of Helium Using High-order Harmonics

The radiative lifetime of the 1s2p(1)P state of helium is measured in a two-colour ionization experiment with a 5% accuracy. The state is excited by the 13th harmonic of a tunable 80 ps laser and ionized by a synchronous ultraviolet laser, with a variable time delay. This experiment demonstrates that the high harmonics generated in a jet of rare gas exposed to an intense laser field provide a tunable short-pulse xuv source ideally suited for pump/probe type of studies and, in particular, short lifetime measurements

Root biomass in cereals, catch crops and weeds can be reliably estimated without considering aboveground biomass

Reliable information on belowground plant biomass is essential to estimate belowground carbon inputs to soils. Estimations of belowground plant biomass are often based on a fixed allometric relationship of plant biomass between aboveground and belowground parts. However, environmental and management factors may affect this allometric relationship making such estimates uncertain and biased. Therefore, we aimed to explore how root biomass for typical cereal crops, catch crops and weeds could most reliably be estimated. Published and unpublished data on aboveground and root biomass (corrected to 0–25 cm depth) of cereal crops (wheat and barley), catch crops and weeds were collected from studies in Denmark. Leave one out cross validation was used to determine the model that could best estimate root biomass. Root biomass varied with year, farming system (organic versus conventional) and cereal species. Shoot and root biomass of catch crops were higher than for weeds (sampled in late autumn), and farming system significantly affected root biomass of catch crops and weeds. The use of fixed root biomass based on the most influential factors (farming system and species) provided the lowest error of prediction for estimation of root biomass, compared with the use of fixed allometric relations, such as root/shoot ratio. For cereal crops, the average root dry matter in organic farming systems was 218 g m−2 (243 and 193 g m−2 for wheat and barley, respectively), but in conventional systems only 139 g m−2 (142 and 129 g m−2 for wheat and barley, respectively). For catch crops and weeds, the root dry matter in organic farming systems were around 127 and 35 g m−2, and in conventional farming systems 75 and 28 g m−2, respectively. In conclusion, the present analysis indicates that root biomass in cereals, catch crops and weeds can be reliably estimated without considering aboveground biomass, and it may be better estimated using fixed values based on species and farming systems than using fixed allometric ratios

Spectrum of mutations in the CFTR gene of patients with classical and atypical forms of cystic fibrosis from southwestern Sweden: Identification of 12 novel mutations

Cystic fibrosis (CF) is caused by mutations in the CFTR gene. The spectrum of CFTR mutations varies between populations and depends on different factors, such as ethnic background and geographical location. The extensive CFTR mutation screening of 129 patients with classical or atypical CF from the south-western region of Sweden revealed the presence of 37 CFTR mutations, including 12 novel alleles. The overall mutation detection rate in this study population was 92%, the highest among all tested regions in Sweden. Eight mutations with a frequency above 1% (ΔF508, 394delTT, R117C, 3659delC, E60X, 1112delT, R764X, and 621 + 1G → T) accounted for 78% of CF chromosomes and have been recommended for inclusion in the CFTR mutation screening panel for molecular diagnosis of CF in this region. The multiple occurrence of specific CFTR alleles less common than the predominant ΔF508 mutation (394delTT, R117C, 3659delC) allowed for genotype-phenotype comparisons and revealed consistent relationships between these mutations and disease severity.published_or_final_versio