Atrioventricular conduction in children of women with systemic lupus erythematosus

The neonatal lupus syndrome consists of transient cutaneous lupus lesions or permanent congenital complete heart block (or hepatic fibrosis), or both, in infants born to mothers with systemic lupus erythematosus (SLE). The frequency of conduction abnormalities was examined in 86 offspring of 53 women affected by SLE. Electrocardiograms from the offspring demonstrated normal sinus rhythm in 84 of 86 offspring. The PR interval was normal for age (95th percentile (i.e., first-degree heart block) for both age and heart rate. The PR interval of the other 6 subjects with first-degree heart block for age or heart rate (>=95th percentile) was <=0.18 second. In contrast, using a rank assignment of PR intervals in relation to heart rate and age derived from published standards, grouped data indicated that heart rate adjusted for age was greater and PR interval adjusted for heart rate longer in offspring of mothers who had the onset of SLE before or during pregnancy than in the normal population; this observation did not hold for offspring whose mothers developed SLE after the pregnancy. These findings indicate that offspring of mothers with SLE, even in the absence of an abnormal electrocardiogram, may have experienced a maternal internal environment that produces subclinical changes in atrioventricular conduction. However, newborns with a normal pulse rate are unlikely to have significant abnormalities in atrioventricular conduction and do not need screening electrocardiograms at birth.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31047/1/0000724.pd

Theoretical and technological building blocks for an innovation accelerator

The scientific system that we use today was devised centuries ago and is inadequate for our current ICT-based society: the peer review system encourages conservatism, journal publications are monolithic and slow, data is often not available to other scientists, and the independent validation of results is limited. Building on the Innovation Accelerator paper by Helbing and Balietti (2011) this paper takes the initial global vision and reviews the theoretical and technological building blocks that can be used for implementing an innovation (in first place: science) accelerator platform driven by re-imagining the science system. The envisioned platform would rest on four pillars: (i) Redesign the incentive scheme to reduce behavior such as conservatism, herding and hyping; (ii) Advance scientific publications by breaking up the monolithic paper unit and introducing other building blocks such as data, tools, experiment workflows, resources; (iii) Use machine readable semantics for publications, debate structures, provenance etc. in order to include the computer as a partner in the scientific process, and (iv) Build an online platform for collaboration, including a network of trust and reputation among the different types of stakeholders in the scientific system: scientists, educators, funding agencies, policy makers, students and industrial innovators among others. Any such improvements to the scientific system must support the entire scientific process (unlike current tools that chop up the scientific process into disconnected pieces), must facilitate and encourage collaboration and interdisciplinarity (again unlike current tools), must facilitate the inclusion of intelligent computing in the scientific process, must facilitate not only the core scientific process, but also accommodate other stakeholders such science policy makers, industrial innovators, and the general public

The use and development of quantitative reliability and safety analysis in New product design

xiv, 212 p. : il.; 24 cm

Open IEC 61508 Certification of Products

IEC 61508 has been in use for several years since the final parts were released in 2000. Although written from the perspective of a bespoke system, it is more commonly used to certify products for a given SIL level. Valid product certification schemes must involve the assessment of specific product design details as well as an assessment of the safety management system of the product manufacturer and the personnel competency of those professionals involved in the product creation. A proper assessment of a product must completely cover all the requirements of the IEC 61508 standard including the safety management system and build a safety case. The safety case must list each requirement, an argument as to how the product design or its creation process meets the requirement and the necessary evidence to provide reasonable credibility for the argument. This safety case must be available for inspection. Although the safety case typically contains manufacturer proprietary information, those who wish to review the full safety case should be able to do so, perhaps under confidentiality agreement. In addition, an open IEC 61508 certification must include a public certification report that provides an overview of the assessment and the product limitations, if any. This paper describes an assessment technique for product designs and the product development process that produces a full safety case as well as additional public documentation. This “open certification ” method has been used in dozens of instances on product design process. The assessment experiences to date show that most of the problems with conventional methods are solved or at least improved

Investigation of Adhesion Formation in New Stainless Steel Trim Spring Operated Pressure Relief Valves,”

Examination of proof test data for new (not previously installed) stainless steel (SS) trim spring operated pressure relief valves (SOPRV) reveals that adhesions form between the seat and disk in about 46% of all such SOPRV. The forces needed to overcome these adhesions can be sufficiently large to cause the SOPRV to fail its proof test (FPT) prior to installation. Furthermore, a significant percentage of SOPRV which are found to FPT are also found to "fail to open" (FTO) meaning they would not relief excess pressure in the event of an overpressure event. The cases where adhesions result in FTO or FPT appear to be confined to SOPRV with diameters less than or equal to 1 in. and set pressures less than 150 pounds per square inch gauge (psig) and the FTO are estimated to occur in 0.31% to 2.00% of this subpopulation of SS trim SOPRV. The reliability and safety implications of these finding for end users who do not perform pre-installation testing of SOPRV are discussed

Investigation Of Adhesion Formation In New Stainless Steel Trim Spring Operated Pressure Relief Valves

Examination of proof test data for new (not previously installed) stainless steel (SS) trim spring operated pressure relief valves (SOPRV) reveals that adhesions form between the seat and disc in about 46% of all such SOPRV. The forces needed to overcome these adhesions can be sufficiently large to cause the SOPRV to fail its proof test (FPT) prior to installation. Furthermore, a significant percentage of SOPRV which are found to FPT are also found to ''fail to open'' (FTO) meaning they would not relief excess pressure in the event of an overpressure event. The cases where adhesions result in FTO or FPT appear to be confined to SOPRV with diameters < 1 in and set pressures < 150 psig and the FTO are estimated to occur in 0.31% to 2.00% of this subpopulation of SS trim SOPRV. The reliability and safety implications of these finding for end-users who do not perform pre-installation testing of SOPRV are discussed

Loess record of the Pleistocene–Holocene transition on the northern and central Great Plains, USA

Various lines of evidence support conflicting interpretations of the timing, abruptness, and nature of climate change in the Great Plains during the Pleistocene–Holocene transition. Loess deposits and paleosols on both the central and northern Great Plains provide a valuable record that can help address these issues. A synthesis of new and previously reported optical and radiocarbon ages indicates that the Brady Soil, which marks the boundary between late Pleistocene Peoria Loess and Holocene Bignell Loess, began forming after a reduction in the rate of Peoria Loess accumulation that most likely occurred between 13.5 and 15 cal ka. Brady Soil formation spanned all or part of the Bølling-Allerød episode (approximately 14.7–12.9 cal ka) and all of the Younger Dryas episode (12.9–11.5 cal ka) and extended at least 1000 years beyond the end of the Younger Dryas. The Brady Soil was buried by Bignell Loess sedimentation beginning around 10.5–9 cal ka, and continuing episodically through the Holocene. Evidence for a brief increase in loess influx during the Younger Dryas is noteworthy but very limited. Most late Quaternary loess accumulation in the central Great Plains was nonglacigenic and was under relatively direct climatic control. Thus, Brady Soil formation records climatic conditions that minimized eolian activity and allowed effective pedogenesis, probably through relatively high effective moisture. Optical dating of loess in North Dakota supports correlation of the Leonard Paleosol on the northern Great Plains with the Brady Soil. Thick loess in North Dakota was primarily derived from the Missouri River floodplain; thus, its stratigraphy may in part reflect glacial influence on the Missouri River. Nonetheless, the persistence of minimal loess accumulation and soil formation until 10 cal ka at our North Dakota study site is best explained by a prolonged interval of high effective moisture correlative with the conditions that favored Brady Soil formation. Burial of both the Brady Soil and the Leonard Paleosol by renewed loess influx probably represents eolian system response that occurred when gradual change toward a drier climate eventually crossed the threshold for eolian activity. Overall, the loess–paleosol sequences of the central and northern Great Plains record a broad peak of high effective moisture across the late Pleistocene to Holocene boundary, rather than well-defined climatic episodes corresponding to the Bølling-Allerød and Younger Dryas episodes in the North Atlantic region

Investigation of Adhesion Formation in New Stainless Steel Trim Spring Operated Pressure Relief Valves

Examination of proof test data for new (not previously installed) stainless steel (SS) trim spring operated pressure relief valves (SOPRV) reveals that adhesions form between the seat and disc in about 46% of all such SOPRV. The forces needed to overcome these adhesions can be sufficiently large to cause the SOPRV to fail its proof test (FPT) prior to installation. Furthermore, a significant percentage of SOPRV which are found to FPT are also found to ''fail to open'' (FTO) meaning they would not relief excess pressure in the event of an overpressure event. The cases where adhesions result in FTO or FPT appear to be confined to SOPRV with diameters < 1 in and set pressures < 150 psig and the FTO are estimated to occur in 0.31% to 2.00% of this subpopulation of SS trim SOPRV. The reliability and safety implications of these finding for end-users who do not perform pre-installation testing of SOPRV are discussed

The Effects of Maintenance Actions on the Average Probability of Failure on Demand of Spring Operated Pressure Relief Valves Contributed by the Pressure Vessel and Piping Division of ASME for publication in the JOURNAL OF PRESSURE VESSEL TECHNOLOGY. Manus

The safety integrity level (SIL) of equipment used in safety instrumented functions is determined by the average probability of failure on demand (PFDavg) computed at the time of periodic inspection and maintenance, i.e., the time of proof testing. The computation of PFDavg is generally based solely on predictions or estimates of the assumed constant failure rate of the equipment. However, PFDavg is also affected by maintenance actions (or lack thereof) taken by the end user. This paper shows how maintenance actions can affect the PFDavg of spring operated pressure relief valves (SOPRV) and how these maintenance actions may be accounted for in the computation of the PFDavg metric. The method provides a means for quantifying the effects of changes in maintenance practices and shows how these changes impact plant safety. In a properly operating SOPRV, a spring exerts a downward force/pressure on the disk pressing the disk against the seat. The seat is the top surface of the wall of the nozzle. The green circles in During normal plant operation, the SOPRV is in the closed position. If the process pressure increases beyond that of the spring set pressure, the disk will be lifted allowing process fluid to flow through the outlet thereby relieving excess process pressure. When the process pressure returns to the closing pressure of the SOPRV, the disk once again closes against the seat to provide a fluid tight seal and the process proceeds normally. The SOPRV can fail in a number of ways. If the SOPRV either spuriously opens or fails to form a fluid tight seal when the process pressure is within normal ranges, the valve is said to leak. These failure modes usually are considered to be safe failures (provided that the unintended pressure relief and fluid release do not themselves induce a safety hazard). On the other hand, if the SOPRV does not open under conditions of excessive process pressure, the valve is said to be "fail to open" (FTO) or to be "stuck shut," and this is a dangerous failure. PFDavg measures the average probability of being in this dangerous failure mode when excessive process pressure needs to be relieved. In a process, the occurrence of excessive pressure is called a demand on the SOPRV hence the metric, PFDavg. Because the SOPRV is normally closed, it is not possible to observe the FTO dangerous failure mode during normal operation. Consequently, safety standards, such as Refs. Journal of Pressure Vessel Technology DECEMBER 2015, Vol. 137 / 061601-1 Copyright V C 2015 by ASME identified. Implementation of these maintenance actions will reduce the failure rate and impact PFDavg. The remainder of this paper: • provides background information about the computation of PFDavg relevant to the study • describes the source of data, rationale for data choice, and summarizes the relevant data • presents an analysis of the proof test failure data for a particular group of SOPRV • provides examples of categorizing the FTO and using the results to calculate the necessary parameters for computing PFDavg • shows the impacts of three different levels of maintenance actions on PFDavg under two different assumptions about infant mortality failures and compares these to the ideal case • closes with a discussion of the results and conclusions