The man-related activities of the Gulf Stream Drift Mission

NASA program for evaluating underwater vehicle crew performance as space station operational analo

Term testing: a case study

Purpose and background: The litigation world has many examples of cases where the volume of Electronically Stored Information (ESI) demands that litigators use automatic means to assist with document identification, classification, and filtering. This case study describes one such process for one case. This case study is not a comprehensive analysis of the entire case, only the Term Testing portion. Term Testing is an analytical practice of refining match terms by running in-depth analysis on a sampling of documents. The goal of term testing is to reduce the number of false negatives (relevant / privilege document with no match, also known as “misdetections”) and false positives (documents matched but not actually relevant / privilege) as much as possible. The case was an employment discrimination suit, against a government agency. The collection effort turned up common sources of ESI: hard drives, network shares, CDs and DVDs, and routine e-mail storage and backups. Initial collection, interviews, and reviews had revealed that a few key documents, such as old versions of policies, had not been retained or collected. Then an unexpected source of information was unearthed: one network administrator had been running an unauthorized “just-in-case” tracer on the email system, outside the agency’s document retention policies, which created dozens of tapes full of millions of encrypted compressed emails, covering more years than the agency’s routine email backups. The agency decided to process and review these tracer emails for the missing key documents, even though the overall volume of relevant documents would rise exponentially. The agency had clear motivation to reduce the volume of documents flowing into relevancy and privilege reviews, but had concerns about the defensibility of using an automated process to determine which documents would never be reviewed. The case litigators and Subject Matter Experts (SMEs) decided to use a process of Term Testing to ensure that automated filtering was both defensible and as accurate as possible

Is surgery more effective than non-surgical treatment for spinal stenosis and which non-surgical treatment is more effective? a systematic review

BACKGROUND: Spinal stenosis can be treated both conservatively and with decompression surgery. OBJECTIVES: To explore the effectiveness of surgery vs conservative treatment, and conservative interventions for spinal stenosis. DATA SOURCES: Medline, CINAHL, AMED, PEDro and Cochrane databases, as well as the reference lists of retrieved studies. STUDY SELECTION: The search included non-English studies, and all conservative interventions were included. STUDY APPRAISAL: The PEDro scale was used to assess quality, and levels of evidence were used to synthesise studies where possible. RESULTS: Thirty-one studies met the inclusion criteria, and 18 were high-quality studies. Decompression surgery was more effective than conservative care in four out of five studies, but only one of these was of high quality. In six high-quality studies, there was strong evidence that steroid epidural injections were not effective; in four out of five studies (two of which were of high quality), there was moderate evidence that calcitonin was not effective. There was no evidence for the effectiveness of all other conservative interventions. LIMITATIONS: Further research is needed to determine if decompression surgery is more effective than conservative care, and which conservative care is most effective. CONCLUSION AND IMPLICATIONS: At present, there is no evidence that favours the effect of any conservative management for spinal stenosis. There is an urgent need to see if any conservative treatment can change pain and functional outcomes in spinal stenosis.</p

Calculation of vaporization rates assuming various rate determining steps: Application to the resistojet

The various steps that could control the vaporization rate of a material are discussed. These steps include the actual vaporization, flow rate of matrix gas, chemical reaction, gas diffusion, and solid state diffusion. The applicable equations have been collected from diverse appropriate sources, and their use is explained. Rate equations are derived for conditions where more than one step is rate controlling. Calculations are made for two model materials: rhenium which vaporizes congruently, and tantalum carbide which vaporizes incongruently. The case of vaporization under thermal gradient conditions is also treated. The existence of a thermal gradient in the resistojet means that the vaporization rate of a material may be only one thousandth of that predicted under isothermal conditions. Calculations show that rhenium might have a 100,000 hr lifetime at temperature in a 2500 C resistojet. Tantalum carbide would have a life of only 660 sec under similar conditions

Kinetics of chromium ion absorption by cross-linked polyacrylate films

Three cross-linked ion exchange membranes were studied as to their ability to absorb chromium ion from aqueous chromium III nitrate solutions. Attention was given to the mechanism of absorption, composition of the absorbed product, and the chemical bonding. The membranes were: calcium polyacrylate, polyacrylic acid, and a copolymer of acrylic acid and vinyl alcohol. For the calcium polyacrylate and the copolymer, parabolic kinetics were observed, indicating the formation of a chromium polyacrylate phase as a coating on the membrane. The rate of absorption is controlled by the diffusion of the chromium ion through this coating. The product formed in the copolymer involves the formation of a coordination complex of a chromium ion with 6 carboxylic acid groups from the same molecule. The absorption of the chromium ion by the polyacrylic acid membranes appears to be more complicated, involving cross-linking. This is due to the coordination of the chromium ion with carboxylic acid groups from more than one polymer molecule. The absorption rate of the chromium ion by the calcium salt membrane was found to be more rapid than that by the free polyacrylic acid membrane

Fugacity and concentration gradients in a gravity field

Equations are reviewed which show that at equilibrium fugacity and concentration gradients can exist in gravitational fields. At equilibrium, the logarithm of the ratio of the fugacities of a species at two different locations in a gravitational field is proportional to the difference in the heights of the two locations and the molecular weight of the species. An analogous relation holds for the concentration ratios in a multicomponent system. The ratio is calculated for a variety of examples. The kinetics for the general process are derived, and the time required to approach equilibrium is calculated for several systems. The following special topics are discussed: ionic solutions, polymers, multiphase systems, hydrostatic pressure, osmotic pressure, and solubility gradients in a gravity field

Electrocrystallization in microgravity

Electrocrystallization under microgravity conditions is proposed as a potential method of crystallization that would be almost completely free of fluid convection. Such crystallization may result in purer, more perfect, and larger crystals than is possible under normal gravity conditions. Observations made and data collected during the crystallization process under convection-free conditions should add to our knowledge of the crystallization process. The proposed method would allow easy comparison of crystals growth in space with those grown under normal gravity conditions. Nine types of electrocrystallization are presented: an example of each is discussed. Electrocrystallization is compared with the compartmental crystallization method used by 3M Corporation in recent shuttle experiments

The principles of integration in urban transport strategies

Integration as a principle in urban transport policy is frequently advocated but rarely defined. We suggest a range of types of integration, and highlight the problems in developing an effective integrated strategy, given the number of variables involved. We argue that integration should be designed to serve agreed objectives of transport policy, rather than being an objective in its own right. We then consider the principles for designing an effective integrated strategy. We define the concept of synergy, which is often advocated as a benefit of integration, and discuss whether it, and other aggregation benefits short of true synergy, are achievable. We then consider the alternative approach of using integration to overcome barriers, an approach which is likely to be in conflict with pursuit of synergy, but more likely to lead to readily implemented strategies. We then review a number of examples where these principles have been applied, and investigate them to assess whether synergy has been demonstrated. Generally we find little evidence of synergy in outcome indicators. We conclude with some more general guidance on approaches to integration

The Birth of Semantics

We attempt here to trace the evolution of Frege’s thought about truth. What most frames the way we approach the problem is a recognition that hardly any of Frege’s most familiar claims about truth appear in his earliest work. We argue that Frege’s mature views about truth emerge from a fundamental re-thinking of the nature of logic instigated, in large part, by a sustained engagement with the work of George Boole and his followers, after the publication of Begriffsschrift and the appearance of critical reviews by members of the Boolean school