Toxicological approach to setting spacecraft maximum allowable concentrations for carbon monoxide

The Spacecraft Maximum Allowable Concentrations (SMACs) are exposure limits for airborne chemicals used by NASA in spacecraft. The aim of these SMACs is to protect the spacecrew against adverse health effects and performance decrements that would interfere with mission objectives. Because of the 1 and 24 hr SMACs are set for contingencies, minor reversible toxic effects that do not affect mission objectives are acceptable. The 7, 30, or 180 day SMACs are aimed at nominal operations, so they are established at levels that would not cause noncarcinogenic toxic effects and more than one case of tumor per 1000 exposed individuals over the background. The process used to set the SMACs for carbon monoxide (CO) is described to illustrate the approach used by NASA. After the toxicological literature on CO was reviewed, the data were summarized and separated into acute, subchronic, and chronic toxicity data. CO's toxicity depends on the formation of carboxyhemoglobin (COHb) in the blood, reducing the blood's oxygen carrying capacity. The initial task was to estimate the COHb levels that would not produce toxic effects in the brain and heart

The Exchange Rate and Interest Rate Differential Relationship: Evidence from Two Financial Crises

This paper examines the contemporaneous and inter-temporal interaction between real exchange rate and real interest rate differential in the two financial crises of 1997 and 2008 by using data from thirteen countries from different world regions. The empirical result shows that negative contemporaneous relationship exists in most countries. In addition, there is little evidence on a systematic inter-temporal relationship between the real interest rate differential and the real exchange rate, and an absence of consistent result in supporting a negative relationship among the thirteen economies. An extremely low change in the conditional correlation between real interest rate differential and real exchange rates can be found in small countries.Contemporaneous, inter-temporal relationship, exchange rate, interest rate differential, financial crisis

Comparing Outcomes Between the Over-the-Top and All-Epiphyseal Techniques for Physeal-Sparing ACL Reconstruction: A Narrative Review.

A variety of techniques are used for physeal-sparing anterior cruciate ligament (ACL) reconstruction; however, there is no clear consensus on the ideal surgical technique, the frequency of complications, and how to best avoid growth disturbance. The purpose of this study was to compare outcomes and complications between over-the-top and all-epiphyseal ACL reconstruction techniques. The hypothesis was that both physeal-sparing reconstruction techniques are efficacious, with similar risk of growth disturbance and complications. The Embase and PubMed databases were queried for studies on ACL ruptures in the skeletally immature population from 1985 to 2018. Full-text English studies were included (N = 160). Studies reporting rerupture and/or complications after physeal-sparing ACL reconstruction, specifically growth disturbance, were included (n = 10). Studies were separated into 2 groups: an all-epiphyseal group with femoral and tibial fixation points within the epiphysis and a group that had over-the-top femoral and tibial physeal-sparing reconstruction. Complications not specific to the pediatric population were excluded. Demographics, evaluation of skeletal maturity, surgical technique, growth disturbance, rerupture, and patient-reported outcome scores were collected. Data were analyzed in aggregate. The 10 studies included 482 knees. The mean age was 12.0 years; 81% of patients were male; and mean follow-up was 47.7 months. A total of 178 patients underwent all-epiphyseal reconstruction, and 298 had the femoral graft placed over the top. The rerupture rate was 9.0% (16 of 178) in the all-epiphyseal group and 7.2% (14 of 195) in the over-the-top group, of which 82% required revision reconstruction. Six patients had overgrowth in the all-epiphyseal group (mean, 1.8 cm) and 1 patient in the over-the-top group (1.5 cm). Three angular deformities occurred, all of which were in the over-the-top group. Both physeal-sparing ACL reconstruction techniques are successful. Overgrowth was more common in the all-epiphyseal group and angular deformity in the over-the-top group. Rerupture rates were similar between the groups. The authors recommend standardization of skeletal age assessment and baseline lower extremity alignment films

Covariant hamiltonian dynamics

We discuss the covariant formulation of the dynamics of particles with abelian and non-abelian gauge charges in external fields. Using this formulation we develop an algorithm for the construction of constants of motion, which makes use of a generalization of the concept of Killing vectors and tensors in differential geometry. We apply the formalism to the motion of classical charges in abelian and non-abelian monopole fieldsComment: 15 pages, no figure

Compositional strategy of the book of Judges: an inductive, rhetorical study

Under historical critical scholarship, the book of Judges is generally considered a composite work comprising three distinct and essentially unrelated sections. The central section (2:6-16:31), redacted out of traditional source material, is believed to be originally a part of the larger Deuteronomistic History that runs from Deuteronomy to Kings. The prologue (1:1-2:5) and epilogue (17:1-21:25), on the other hand, are seen as independent compositions that are only artificially appended onto the central section at a later stage of the book's redactional history.In the last two decades, there has been an increasing tendency for the book to be read synchronically as an integrated whole. Although synchronic scholars have drawn attention to the presence of thematic links that connect the different sections of the book, they have yet to justify their integrative approach by exploring whether such links are established by design, and if so, whether they imply compositional unity for the book as a whole in its current canonical form. The present thesis thus seeks to remedy this lack.In Chapter 1, the present thesis is placed in its historical context as scholarship on Judges in the past century is critically surveyed. In Chapters 2-4, rhetorical links between the prologue and the epilogue, the epilogue and central section, and the prologue and central sections are respectively examined in detail. As the evidence seems to suggest that such links are established by conscious design, the implication is that at the compositional level, a closer relationship than has been recognised thus far may indeed exist between the three sections.Recognising that any claim of compositional unity for Judges would inevitably have to answer questions regarding apparent discrepancies in viewpoints within the book, in Chapter 5, the issue of kingship, concerning which critical scholars have discerned divergent voices within the book, is explored. Specifically, it is argued that the "king" referred to in the allegedly pro-monarchic refrain cannot be a reference to the Israelite monarchy to come, but is more likely a reference to YHWH's kingship over His people. Such an understanding would therefore eliminate the problem of divergent viewpoints within the bookIn the final chapter, the various observations and conclusions drawn in previous chapters are brought together, and a case is put forth that the person responsible for the selection and arrangement of the material in the central section must have been the very same person who composed the prologue and epilogue of Judges. This means that the current canonical form of Judges may indeed be a unified piece of composition that can justifiably be read as an integrative whole. Moreover, based on the rhetorical concerns discernible through the various links, it is also possible to identify the implied rhetorical agenda of the book as a call for the rerecognition of the kingly authority of YHWH. This would constitute an implied solution to the progressive deterioration witnessed throughout the book, both at the national and leadership level

Universal Behavior in Large-scale Aggregation of Independent Noisy Observations

Aggregation of noisy observations involves a difficult tradeoff between observation quality, which can be increased by increasing the number of observations, and aggregation quality which decreases if the number of observations is too large. We clarify this behavior for a protypical system in which arbitrarily large numbers of observations exceeding the system capacity can be aggregated using lossy data compression. We show the existence of a scaling relation between the collective error and the system capacity, and show that large scale lossy aggregation can outperform lossless aggregation above a critical level of observation noise. Further, we show that universal results for scaling and critical value of noise which are independent of system capacity can be obtained by considering asymptotic behavior when the system capacity increases toward infinity.Comment: 10 pages, 3 figure