Development of advanced direct perception displays for nuclear power plants to enhance monitoring, control and fault management

Traditional Single-Sensor-Single Indicator (SSSI) displays are poorly matched to the cognitive abilities of operators, especially for large and complex systems. It is difficult for operators to monitor very large arrays of displays and controls, and to integrate the information displayed therein. In addition, standard operating procedures (SOPs) are bulky (running to many hundreds of pages) and difficult to use, and operators may become lost. For these reasons, and also because it is becoming increasingly difficult to find replacements for aging hardware components, there is a trend towards computerized graphical interfaces for nuclear power plants (NPPs). There is, however, little rational theory for display design in this domain. This report describes some recent theoretical developments and shows how to develop displays which will greatly reduce the cognitive load on the operator and allow the use of perceptual rather than cognitive mechanisms while using SON and to support state diagnosis and fault management. The report outlines the conceptual framework within which such a new approach could be developed, and provides an example of how the operating procedures for the start-up sequence of a NPP could be realized. A detailed description of a set of displays for a graphical interface for the SON of the feedwater system is provided as an example of how the proposed approach could be realized, and a general account of how it would fit into the overall start-up sequence is given. Examples of {open_quotes}direct perception{close_quotes} or {open_quotes}ecological{close_quotes} configural state space displays to support the use of the proposed direct manipulation SOP interface are provided, and also a critical discussion which identifies some difficulties which may be anticipated should the general approach herein advocated be adopted

Robotic Pancreatoduodenectomy: Patient Selection, Volume Criteria, and Training Programs

INTRODUCTION: There has been a rapid development in minimally invasive pancreas surgery in recent years. The most recent innovation is robotic pancreatoduodenectomy. Several studies have suggested benefits as compared to the open or laparoscopic approach. This review provides an overview of studies concerning patient selection, volume criteria, and training programs for robotic pancreatoduodenectomy and identified knowledge gaps regarding barriers for safe implementation of robotic pancreatoduodenectomy. MATERIALS AND METHODS: A Pubmed search was conducted concerning patient selection, volume criteria, and training programs in robotic pancreatoduodenectomy. RESULTS: A total of 20 studies were included. No contraindications were found in patient selection for robotic pancreatoduodenectomy. The consensus and the Miami guidelines advice is a minimum annual volume of 20 robotic pancreatoduodenectomy procedures per center, per year. One training program was identified which describes superior outcomes after the training program and shortening of the learning curve in robotic pancreatoduodenectomy. CONCLUSION: Robotic pancreatoduodenectomy is safe and feasable for all indications when performed by specifically trained surgeons working in centers who can maintain a minimum volume of 20 robotic pancreatoduodenectomy procedures per year. Large proficiency-based training program for robotic pancreatoduodenectomy seem essential to facilitate a safe implementation and future research on robotic pancreatoduodenectomy

Infrared spectrum of formamide in the solid phase

Infrared spectra of solid formamide are reported as a function of temperature. Solid formamide samples were prepared at 30 K and then annealed to higher temperatures (300 K) with infrared transmission spectra being recorded over the entire temperature range. The NH2 vibrations of the formamide molecule were found to be particularly very sensitive to temperature change. The IR spectra revealed a phase change occurring in solid formamide between 155 and 165 K. Spectral changes observed above and below the phase transition may be attributed to a rearrangement between formamide dimers and the formation of polymers is proposed at higher temperatures

The Science of Sungrazers, Sunskirters, and Other Near-Sun Comets

This review addresses our current understanding of comets that venture close to the Sun, and are hence exposed to much more extreme conditions than comets that are typically studied from Earth. The extreme solar heating and plasma environments that these objects encounter change many aspects of their behaviour, thus yielding valuable information on both the comets themselves that complements other data we have on primitive solar system bodies, as well as on the near-solar environment which they traverse. We propose clear definitions for these comets: We use the term near-Sun comets to encompass all objects that pass sunward of the perihelion distance of planet Mercury (0.307 AU). Sunskirters are defined as objects that pass within 33 solar radii of the Sun’s centre, equal to half of Mercury’s perihelion distance, and the commonly-used phrase sungrazers to be objects that reach perihelion within 3.45 solar radii, i.e. the fluid Roche limit. Finally, comets with orbits that intersect the solar photosphere are termed sundivers. We summarize past studies of these objects, as well as the instruments and facilities used to study them, including space-based platforms that have led to a recent revolution in the quantity and quality of relevant observations. Relevant comet populations are described, including the Kreutz, Marsden, Kracht, and Meyer groups, near-Sun asteroids, and a brief discussion of their origins. The importance of light curves and the clues they provide on cometary composition are emphasized, together with what information has been gleaned about nucleus parameters, including the sizes and masses of objects and their families, and their tensile strengths. The physical processes occurring at these objects are considered in some detail, including the disruption of nuclei, sublimation, and ionisation, and we consider the mass, momentum, and energy loss of comets in the corona and those that venture to lower altitudes. The different components of comae and tails are described, including dust, neutral and ionised gases, their chemical reactions, and their contributions to the near-Sun environment. Comet-solar wind interactions are discussed, including the use of comets as probes of solar wind and coronal conditions in their vicinities. We address the relevance of work on comets near the Sun to similar objects orbiting other stars, and conclude with a discussion of future directions for the field and the planned ground- and space-based facilities that will allow us to address those science topics

Precision Pion-Proton Elastic Differential Cross Sections at Energies Spanning the Delta Resonance

A precision measurement of absolute pi+p and pi-p elastic differential cross sections at incident pion laboratory kinetic energies from T_pi= 141.15 to 267.3 MeV is described. Data were obtained detecting the scattered pion and recoil proton in coincidence at 12 laboratory pion angles from 55 to 155 degrees for pi+p, and six angles from 60 to 155 degrees for pi-p. Single arm measurements were also obtained for pi+p energies up to 218.1 MeV, with the scattered pi+ detected at six angles from 20 to 70 degrees. A flat-walled, super-cooled liquid hydrogen target as well as solid CH2 targets were used. The data are characterized by small uncertainties, ~1-2% statistical and ~1-1.5% normalization. The reliability of the cross section results was ensured by carrying out the measurements under a variety of experimental conditions to identify and quantify the sources of instrumental uncertainty. Our lowest and highest energy data are consistent with overlapping results from TRIUMF and LAMPF. In general, the Virginia Polytechnic Institute SM95 partial wave analysis solution describes our data well, but the older Karlsruhe-Helsinki PWA solution KH80 does not.Comment: 39 pages, 22 figures (some with quality reduced to satisfy ArXiv requirements. Contact M.M. Pavan for originals). Submitted to Physical Review

Glycoprotein gene truncation in avian metapneumovirus subtype C isolates from the United States

The length of the published glycoprotein (G) gene sequences of avian metapneumovirus subtype-C (aMPV-C) isolated from domestic turkeys and wild birds in the United States (1996–2003) remains controversial. To explore the G gene size variation in aMPV-C by the year of isolation and cell culture passage levels, we examined 21 turkey isolates of aMPV-C at different cell culture passages. The early domestic turkey isolates of aMPV-C (aMPV/CO/1996, aMPV/MN/1a-b, and 2a-b/97) had a G gene of 1,798 nucleotides (nt) that coded for a predicted protein of 585 amino acids (aa) and showed >97% nt similarity with that of aMPV-C isolated from Canada geese. This large G gene got truncated upon serial passages in Vero cell cultures by deletion of 1,015 nt near the end of the open reading frame. The recent domestic turkey isolates of aMPV-C lacked the large G gene but instead had a small G gene of 783 nt, irrespective of cell culture passage levels. In some cultures, both large and small genes were detected, indicating the existence of a mixed population of the virus. Apparently, serial passage of aMPV-C in cell cultures and natural passage in turkeys in the field led to truncation of the G gene, which may be a mechanism of virus evolution for survival in a new host or environment

Postnatal development of intestinal immune system in piglets: implications for the process of weaning

European-wide directives are in place to establish a sustainable production of pigs without using production enhancers and chemotherapeutics. Thus, an economically-viable pig production is now only possible when the physiological mechanisms of defense against pathogens and tolerance against nutrients and commensal bacteria in the intestinal immune system are taken into account. During the postnatal period the piglet is facing first the time large amounts of new antigens and at weaning a second wave of nutritional antigens is entering the intestinal tract. The appropriate development of humoral and cellular functions of the intestinal immune system is essential for optimum growth and performance of the piglets. The integrity of the intestinal surfaces is a prerequisite of intestinal immunity and tolerance. Secretory IgA serves to exclude harmful antigens from uptake. The induction of intestinal immune reactions starts with antigen presentation by professional antigen presenting cells of Peyer's patches and mesenteric lymph nodes. In addition, the intestinal lamina propria serves as a mucosal compartment for regulation of immune responses. Here especially T regulatory cells (CD4(+) CD25(+)) have their function for maintaining intestinal homeostasis. The network of mucosal T and B cells develops after birth in a programmed sequence; it is almost completed at week 7 after birth. Weaning is associated with changes in the regulation of the lymphoid cells in the mucosa. In small and large intestine increases in pro- and anti-inflammatory cytokines were observed after weaning in lymphocytes. Epithelial cells were studied both in intestinal samples and in vitro. Here the cytokine patterns provide evidence that weaning is inducing a transient inflammation of the mucosa. Piglets weaned under conventional conditions have a thicker mucosa than pigs weaned from isolators. Cells of isolator-reared pigs show slightly higher levels of activation markers - probably reflecting the interaction of the foreign protein derived from bovine milk. The results presented in this overview demonstrate that further effort is necessary to elucidate the function of the porcine intestinal immune system in the postnatal period and at the time of weaning to provide criteria for porcine intestinal health