Aerospace Size Standard for O-Rings

10.4271/as568 ◽  
1971 ◽  
Author(s):  
Keyword(s):  
Size Standard

scholarly journals The Sampling Distribution of Disease-Associated Alleles

Genetics ◽  
1997 ◽  
Vol 147 (4) ◽  
pp. 1855-1861 ◽  
Author(s):  
Montgomery Slatkin ◽  
Bruce Rannala
Keyword(s):  
Low Frequency ◽  
Null Model ◽  
Sampling Distribution ◽  
Death Process ◽  
Published Data ◽  
Data Sets ◽  
Likelihood Functions ◽  
Alternative Hypotheses ◽  
Size Standard ◽  
Birth Death

Abstract A theory is developed that provides the sampling distribution of low frequency alleles at a single locus under the assumption that each allele is the result of a unique mutation. The numbers of copies of each allele is assumed to follow a linear birth-death process with sampling. If the population is of constant size, standard results from theory of birth-death processes show that the distribution of numbers of copies of each allele is logarithmic and that the joint distribution of numbers of copies of k alleles found in a sample of size n follows the Ewens sampling distribution. If the population from which the sample was obtained was increasing in size, if there are different selective classes of alleles, or if there are differences in penetrance among alleles, the Ewens distribution no longer applies. Likelihood functions for a given set of observations are obtained under different alternative hypotheses. These results are applied to published data from the BRCA1 locus (associated with early onset breast cancer) and the factor VIII locus (associated with hemophilia A) in humans. In both cases, the sampling distribution of alleles allows rejection of the null hypothesis, but relatively small deviations from the null model can account for the data. In particular, roughly the same population growth rate appears consistent with both data sets.

Male reproductive behaviour and spawning success in a temperate zone goby, Coryphopterus nicholsi

1982 ◽  
Vol 60 (10) ◽  
pp. 2309-2316 ◽  
Author(s):  
Kathleen S. Cole
Keyword(s):  
Reproductive Success ◽  
Standard Length ◽  
Reproductive Behaviour ◽  
Reproductive Season ◽  
Temperate Zone ◽  
Testicular Development ◽  
Male Size ◽  
Size Standard ◽  
Highly Correlated ◽  
Spawning Success

Coryphopterus nicholsi is a temperate zone marine goby. In laboratory groups of fish, females preferentially spawn with dominant males; assessment of dominance appears to be based upon courting vigour. Male size (standard length) and dominance were often, but not always, highly correlated. In contrast, there was no consistent correlation between territorial quality and spawning success. Smaller males in laboratory groups did not court females or guard eggs. However, their behaviour and testicular development during the reproductive season suggest that they may engage in sneak spawning. Dominant males are more likely to successfully guard eggs against conspecific predators than are subordinate males, and hence females should have greater reproductive success if they choose dominant males for spawning partners.

The Effects of Acute Exercise on Retroactive Memory Interference

2019 ◽  
Vol 34 (1) ◽  
pp. 25-31 ◽  
Author(s):  
Paul D. Loprinzi ◽  
Emily Frith ◽  
Lindsay Crawford
Keyword(s):  
Acute Exercise ◽  
Experimental Studies ◽  
Memory Task ◽  
Word List ◽  
Moderate Intensity ◽  
Long Term Memory ◽  
Memory Interference ◽  
Standard Difference ◽  
Size Standard ◽  
List Memory

Purpose: Retroactive interference involves the disruption of previously encoded information from newly learned information and thus may impair the consolidation of long-term memory. The objective of this study was to evaluate whether acute exercise can attenuate retroactive memory interference. Design: Three experimental studies were employed. Experiment 1 employed a between-subject randomized control trial (RCT) involving moderate-intensity walking (15 minutes). Experiment 2 employed a between-subject RCT involving high-intensity jogging (15 minutes). Experiment 3 employed a within-subject RCT involving moderate-intensity walking (15 minutes). Setting: University setting. Participants: One hundred twelve young adults. Measures: After exercise, memory interference was evaluated from an episodic word-list memory task, involving the recall of 2 word lists. Results: The pooled effect size (standard difference in means: −0.35; 95% confidence interval: −0.64 to −0.06) across the 3 experiments was statistically significant ( P = .01). Conclusion: We provide suggestive evidence that acute, short-duration exercise may help attenuate a retroactive memory interference effect. Implications of these findings for exercise to improve memory and attenuate memory decay are discussed.

scholarly journals A Measurement Method of Microsphere with Dual Scanning Probes

2019 ◽  
Vol 9 (8) ◽  
pp. 1598 ◽  
Author(s):  
Fang ◽  
Huang ◽  
Xu ◽  
Cheng ◽  
Chen ◽  
...  
Keyword(s):  
Measurement Method ◽  
Coordinate Measuring Machine ◽  
Quartz Tuning Fork ◽  
Cross Sectional ◽  
Scanning Probes ◽  
Repeatability Error ◽  
Measurement Results ◽  
Size Standard ◽  
Measuring Machine ◽  
Tungsten Tip

The probe tip of a micro-coordinate Measuring Machine (micro-CMM) is a microsphere with a diameter of hundreds of microns, and its sphericity is generally controlled within tens to hundreds of nanometers. However, the accurate measurement of the microsphere morphology is difficult because of the small size and high precision requirement. In this study, a measurement method with two scanning probes is proposed to obtain dimensions including the diameter and sphericity of microsphere. A series of maximum cross-sectional profiles of the microsphere in different angular directions are scanned simultaneously and differently by the scanning probes. By integrating the data of these maximum profiles, the dimensions of the microsphere can be calculated. The scanning probe is fabricated by combining a quartz tuning fork and a tungsten tip, which have a fine vertical resolution at a sub-nano scale. A commercial ruby microsphere is measured with the proposed method. Experiments that involve the scanning of six section profiles are carried out to estimate the dimensions of the ruby microsphere. The repeatability error of one section profile is 15.1 nm, which indicates that the measurement system has favorable repeatability. The mainly errors in the measurement are eliminated. The measured diameter and roundness are all consistent with the size standard of the commercial microsphere. The measurement uncertainty is evaluated, and the measurement results show that the method can be used to measure the dimensions of microspheres effectively.

Characterization of LDMMs

MRS Bulletin ◽  
1990 ◽  
Vol 15 (12) ◽  
pp. 41-43
Keyword(s):  
Spatial Scale ◽  
Cell Size ◽  
Three Dimensional ◽  
Morphological Properties ◽  
Sem Images ◽  
Average Cell Size ◽  
Cell Size Distribution ◽  
Average Cell ◽  
Process Step ◽  
Size Standard

The previous sections of this article described the synthesis, morphologies, and properties of a variety of low-density microcellular materials. This section discusses several of the analytical methods used and developed at the DOE laboratories to characterize these state-of-the-art materials.In some LDMM applications, quantitative measurements of the material's average cell size and cell size distribution are desired. Indeed, the term “microcellular” has little meaning without such information. As seen throughout this article, however, most LDMMs do not have a readily defined cellular character. The more general problem is to quantify the spatial scale(s) of the foam. For this purpose it is necessary to define one or more “measures” of the spatial scale. The possibilities are many and include not only single numbers (e.g., cell size and cell size standard deviation, where “cell size” is meaningful) but also functional descriptions (e.g., correlation functions).SEM provides direct images and, therefore, is the most popular technique for examining LDMM morphology. SEM, however, suffers from at least three limitations: (1) SEM examines only a very small volume of material, and thus is impractical for obtaining average morphological properties; (2) SEM requires that nonconductive LDMMs be coated, a process step that can alter the structure and introduce artifacts (particularly with delicate structures); and (3) SEM images are only two-dimensional projections of real three-dimensional structures.

High Degree of Variability in Reporting of Clinical and Patient-Reported Outcomes After Hip Arthroscopy

2017 ◽  
Vol 46 (12) ◽  
pp. 3040-3046 ◽  
Author(s):  
Austin V. Stone ◽  
Cale A. Jacobs ◽  
T. David Luo ◽  
Molly C. Meadows ◽  
Shane J. Nho ◽  
...  
Keyword(s):  
Outcome Measures ◽  
Hip Arthroscopy ◽  
Alpha Angle ◽  
Patient Reported Outcome ◽  
Harris Hip Score ◽  
Center Edge ◽  
Patient Reported ◽  
Study Characteristics ◽  
Size Standard ◽  
Pro Instruments

Background: Hip arthroscopy for the treatment of intra-articular pathology is a rapidly expanding field. Outcome measures should be reported to document the efficacy of arthroscopic procedures; however, the most effective outcome measures are not established. Purpose: To evaluate the variability in outcomes reported after hip arthroscopy and to compare the responsiveness of patient-reported outcome (PRO) instruments. Study Design: Systematic review. Methods: We reviewed primary hip arthroscopy literature between January 2011 and September 2016 using the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Patient and study characteristics were recorded. Pre- and postoperative means and SDs of PROs were recorded from articles that used 2 or more PROs with a 1-year minimum follow-up. From this subset of articles, we compared the responsiveness between PRO instruments using the effect size, standard response mean, and relative efficiency. Results: We identified 130 studies that met our inclusion/exclusion criteria, which totaled 16,970 patients (17,511 hips, mean age = 37.0 years, mean body mass index = 25.9 kg/m2). Radiographic measures were reported in 100 studies. The alpha angle and center-edge angle were the most common measures. Range of motion was reported in 81 of 130 articles. PROs were reported in 129 of 130 articles, and 21 different PRO instruments were identified. The mean number of PROs per article was 3.2, and 78% used 2 or more PROs. The most commonly used PRO was the modified Harris Hip Score, followed by the Hip Outcome Score (HOS)–Activities of Daily Living, HOS-Sport, visual analog scale, and Nonarthritic Hip Score (NAHS). The 2 most responsive PRO tools were the International Hip Outcome Tool (iHOT)–12 and the NAHS. Conclusion: Outcomes reporting is highly variable in the hip arthroscopy literature. More than 20 different PRO instruments have been used, which makes comparison across studies difficult. A uniform set of outcome measures would allow for clearer interpretation of the hip arthroscopy literature and offer potential conclusions from pooled data. On the basis of our comparative responsiveness results and previously reported psychometric properties of the different PRO instruments, we recommend more widespread adoption of the iHOT PROs instruments to assess hip arthroscopy outcomes.

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