scholarly journals On the relationship between two asymptotic expansions for the distribution of sample mean and its applications

1997 ◽  
Vol 25 (5) ◽  
pp. 2200-2209 ◽  
Author(s):  
Min Tsao ◽  
Rick Routledge
Keyword(s):  
Asymptotic Expansions ◽  
Sample Mean ◽  
The Relationship

SAMPLING STATISTICS AND A SAMPLING SCHEME FOR THE TWOSPOTTED SPIDER MITE, TETRANYCHUS URTICAE (ACARI: TETRANYCHIDAE), ON STRAWBERRIES

1986 ◽  
Vol 118 (8) ◽  
pp. 807-814 ◽  
Author(s):  
D.A. Raworth
Keyword(s):  
Tetranychus Urticae ◽  
Spider Mite ◽  
Negative Binomial ◽  
Sampling Scheme ◽  
Twospotted Spider Mite ◽  
Sample Mean ◽  
The Mean ◽  
Sampling Statistics ◽  
The Relationship ◽  
Twospotted Spider

AbstractA series of samples of the twospotted spider mite, Tetranychus urticae Koch, from 16 experimental populations on “Totem” strawberry, Fragaria × ananassa Duch., were examined to determine the index of dispersion, the variance–mean relationship, the distribution, and the relationship between the mean number of T. urticae/leaflet and the proportion of leaflets without T. urticae. The slope of the variance–mean relationship, 1.64 ± 0.0355(SE), did not differ between sample dates but the intercept decreased significantly (p < 0.01) from 2.56 ± 0.0969 before harvest to 1.76 ± 0.140 during harvest. At 0.0136 T. urticae/leaflet before harvest and 0.0644 T. urticae/leaflet during harvest, the variance equaled the mean, implying that at these densities the data followed the Poisson distribution. Above these densities the data were overdispersed, most samples conforming with the negative binomial distribution but some tending towards greater dispersion than the negative binomial. There was no common k for the negative binomial nor did the data fit the expectation for 1/k that was consistent with the variance–mean relationship. A distribution-free sampling scheme based on the sample mean and the proportion of leaflets without T. urticae () was developed. Tetranychus urticae density can be quickly determined in the field using the naked eye, by iteratively observing leaflets for the presence or absence of T. urticae and referring to a small table that gives both the mean density for a given and the number of leaflets required to obtain a specified standard error.

The Relationship between Tropical Cyclone Intensity Change and the Strength of Inner-Core Convection

2012 ◽  
Vol 140 (4) ◽  
pp. 1164-1176 ◽  
Author(s):  
Haiyan Jiang
Keyword(s):  
Tropical Cyclone ◽  
Brightness Temperature ◽  
Inner Core ◽  
Cumulative Distribution ◽  
Intensity Change ◽  
Sample Mean ◽  
Convective Parameter ◽  
Significant Difference ◽  
Radar Echo ◽  
The Relationship

Convective intensity proxies measured by the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI), Precipitation Radar (PR), and Visible and Infrared Scanner (VIRS) are used to assess the relationship between intense convection in the inner core and tropical cyclone (TC) intensity change. Using the cumulative distribution functions of 24-h intensity changes from the 1998–2008 best-track data for global TCs, five intensity change categories are defined: rapidly intensifying (RI), slowly intensifying, neutral, slowly weakening, and rapidly weakening. TRMM observations of global TCs during 1998–2008 are used to generate the distributions of convective properties in the storm’s inner-core region for different storm intensity change categories. To examine the hypothesis of hot towers near the eye as an indicator of RI, hot towers are defined by precipitation features with 20-dBZ radar echo height reaching 14.5 km. The differences in the convective parameters between rapidly intensifying TCs and slowly intensifying, neutral, slowly weakening, and rapidly weakening TCs are quantified using statistical analysis. It is found that statistically significant differences of three out of four convective intensity parameters in the inner core exist between RI and non-RI storms. Between RI and slowly intensifying TCs, a statistically significant difference exists for the minimum 11-μm IR brightness temperature TB11 in the inner core. This indicates that a relationship does exist between inner-core convective intensity and TC intensity change. The results in this study also suggest that the rate of intensification appears to be influenced by convective activity in the inner core and the ability to predict RI might be further improved by using convective parameters. With regard to different convective proxies, the relationships are different. The minimum TB11, upper-level maximum radar reflectivities, and maximum 20-dBZ radar echo height in the inner core are best associated with the rate of TC intensity change, while the minimum 85-GHz polarization corrected brightness temperature (PCT) shows some ambiguities in relation to intensity change. The minimum 37-GHz PCT shows no significant relationship with TC intensity change, probably because of the contamination of the ice scattering signal by emission from rain and liquid water in this channel. By examining the probability of RI for each convective parameter for which statistically significant differences at the 95% level were found of RI and non-RI cases, it is found that all three parameters provide additional information relative to climatology. The most skillful parameter is minimum TB11, and the second is maximum 20-dBZ height, followed by minimum 85-GHz PCT. However, the increases of RI probability from the larger sample mean by using these predictors are not very large. When using the existence of hot towers as a predictor, it is found that the probabilities of RI and slowly intensifying increase and those of slowly weakening and rapidly weakening decrease for samples with hot towers in the inner core. However, the increases for intensifying and decreases for weakening are not substantial, indicating that hot towers are neither a necessary nor a sufficient condition for RI.

Medicaid and Mortality: New Evidence from Linked Survey and Administrative Data*

2021 ◽  
Author(s):  
Sarah Miller ◽  
Norman Johnson ◽  
Laura R Wherry
Keyword(s):  
Large Scale ◽  
First Year ◽  
Program Participation ◽  
Citizenship Status ◽  
Sample Mean ◽  
Medicaid Enrollment ◽  
New Evidence ◽  
The Relationship ◽  
Medicaid Expansions ◽  
Annual Mortality

Abstract We use large-scale federal survey data linked to administrative death records to investigate the relationship between Medicaid enrollment and mortality. Our analysis compares changes in mortality for near-elderly adults in states with and without Affordable Care Act Medicaid expansions. We identify adults most likely to benefit using survey information on socioeconomic status, citizenship status, and public program participation. We find that, prior to the ACA expansions, mortality rates across expansion and nonexpansion states trended similarly, but beginning in the first year of the policy, there were significant reductions in mortality in states that opted to expand relative to nonexpanders. Individuals in expansion states experienced a 0.132 percentage point decline in annual mortality, a 9.4 percent reduction over the sample mean, as a result of the Medicaid expansions. The effect is driven by a reduction in disease-related deaths and grows over time. A variety of alternative specifications, methods of inference, placebo tests, and sample definitions confirm our main result.

Sleep Deprived or Concussed? The Acute Impact of Self-Reported Insufficient Sleep in College Athletes

2020 ◽  
pp. 1-12 ◽  
Author(s):  
Kaitlin E. Riegler ◽  
Erin T. Guty ◽  
Garrett A. Thomas ◽  
Peter A. Arnett
Keyword(s):  
Neuropsychological Test ◽  
Collegiate Athletes ◽  
Symptom Scale ◽  
Insufficient Sleep ◽  
Sample Mean ◽  
Objective Performance ◽  
Valid Comparison ◽  
The Relationship ◽  
Negative Health Outcomes ◽  
Sleep Difficulties

Abstract Objective: Sleep deprivation is common among both college students and athletes and has been correlated with negative health outcomes, including worse cognition. As such, the current study sought to examine the relationship between sleep difficulties and self-reported symptoms and objective neuropsychological performance at baseline and post-concussion in collegiate athletes. Method: Seven hundred seventy-two collegiate athletes completed a comprehensive neuropsychological test battery at baseline and/or post-concussion. Athletes were separated into two groups based on the amount of sleep the night prior to testing. The sleep duration cutoffs for these group were empirically determined by sample mean and standard deviation (M = 7.07, SD = 1.29). Results: Compared with athletes getting sufficient sleep, those getting insufficient sleep the night prior to baseline reported significantly more overall symptoms and more symptoms from each of the five symptom clusters of the Post-Concussion Symptom Scale. However, there were no significant differences on objective performance indices. Secondly, there were no significant differences on any of the outcome measures, except for sleep symptoms and headache, between athletes getting insufficient sleep at baseline and those getting sufficient sleep post-concussion. Conclusion: Overall, the effect of insufficient sleep at baseline can make an athlete appear similar to a concussed athlete with sufficient sleep. As such, athletes completing a baseline assessment following insufficient sleep could be underperforming cognitively and reporting elevated symptoms that would skew post-concussion comparisons. Therefore, there may need to be consideration of prior night’s sleep when determining whether a baseline can be used as a valid comparison.

scholarly journals Positive Affect Moderates the Relationship Between Salivary Testosterone and a Health Behavior Composite in University Females

2019 ◽  
Vol 27 (3) ◽  
pp. 305-315
Author(s):  
Luci A. Martin ◽  
Mariam Ter-Petrosyan
Keyword(s):  
Health Behavior ◽  
Negative Affect ◽  
Positive Affect ◽  
Asian American ◽  
Saliva Sample ◽  
Future Research ◽  
Positive And Negative Affect ◽  
Sample Mean ◽  
Salivary Testosterone ◽  
The Relationship

Abstract Background Testosterone is released in both men and women and plays an important role in social functioning and motivation. Greater testosterone in women has been associated with negative physical health outcomes, while lower testosterone has been associated with psychological disorders. The following cross-sectional study examined the contribution of salivary testosterone, positive and negative affect, and demographic variables in predicting a composite health behavior score (cigarette use, hours of sleep, fruit/vegetable intake, following an exercise routine). Method The sample (mean age 21.17, SD = 6.13) consisted of 87 female university students asked to complete a demographic and lifestyle behavior questionnaire, the Positive and Negative Affect Schedule, and provide a saliva sample. Participants self-identified as Latina (37.9%), European American (32.2%), Asian American (5.7%), African American (4.6%), or Mixed/other (19.5%). Hierarchical regression analyses were used to examine whether positive and negative affect served as a moderator between salivary testosterone and a health behavior composite. Results Results indicated that positive affect moderated the relationship between salivary testosterone and the composite health behavior score (t = − 2.42, p = .018, Adj. R2 = .21, F (5, 81) = 5.07, p < .001) such that the healthiest behaviors were observed in participants with high positive affect and low salivary testosterone. Findings remained after adjusting for oral contraceptive use, income level, relationship status, and ethnicity. Conclusions These results provide a preliminary foundation for future research examining the interplay of neuroendocrine function, psychological factors (i.e., positive affect), and behavior. Further empirical studies can focus on expanding this research in larger, representative samples.

On the mathematics of exchange processes in fixed columns I. Mathematical solutions and asymptotic expansions

1953 ◽  
Vol 219 (1137) ◽  
pp. 151-171 ◽  
Keyword(s):  
Solid State ◽  
Ion Exchange ◽  
Kinetic Theory ◽  
Asymptotic Expansions ◽  
Initial Conditions ◽  
Fluid Flows ◽  
Physical Problems ◽  
Mathematical Properties ◽  
Exchange Processes ◽  
The Relationship

The paper is intended as a contribution to the mathematical discussion of the exchange processes, of heat or of matter (as in ion exchange or adsorption), that arise when a fluid flows through the pores or voids along a column containing matter in the solid state. The exchange is taken to be governed by a linear or bilinear or Langmuir-type kinetic exchange equation. The matters dealt with include the solution of the exchange and conservation equations for any initial conditions, mathematical properties of and asymptotic expansions for the functions arising, and the appearance of the functions in the solutions of other physical problems. The discussion of the mathematical properties of the functions and their asymptotic expansions is needed to establish the relationship between solutions on the equilibrium theory and those on the kinetic theory, and to find closer approximations to the kinetic-theory solutions.

Interstellar gas in the central region of the Galaxy

1967 ◽  
Vol 31 ◽  
pp. 239-251 ◽  
Author(s):  
F. J. Kerr
Keyword(s):  
Central Region ◽  
Galactic Plane ◽  
Neutral Hydrogen ◽  
Continuum Emission ◽  
Galactic Centre ◽  
Interstellar Gas ◽  
Hydrogen Recombination ◽  
The Galaxy ◽  
Centre Region ◽  
The Relationship

A review is given of information on the galactic-centre region obtained from recent observations of the 21-cm line from neutral hydrogen, the 18-cm group of OH lines, a hydrogen recombination line at 6 cm wavelength, and the continuum emission from ionized hydrogen.Both inward and outward motions are important in this region, in addition to rotation. Several types of observation indicate the presence of material in features inclined to the galactic plane. The relationship between the H and OH concentrations is not yet clear, but a rough picture of the central region can be proposed.

The relationship of the scleractinian corals to the rugose corals

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver
Keyword(s):  
Critical Points ◽  
Scleractinian Corals ◽  
Convincing Evidence ◽  
Early Triassic ◽  
Rugose Corals ◽  
History Of ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Biologic Factors

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.

Choosing a Markov blanket

2020 ◽  
Vol 43 ◽  
Author(s):  
Thomas Parr
Keyword(s):  
Markov Blanket ◽  
Target Article ◽  
The Relationship

Abstract This commentary focuses upon the relationship between two themes in the target article: the ways in which a Markov blanket may be defined and the role of precision and salience in mediating the interactions between what is internal and external to a system. These each rest upon the different perspectives we might take while “choosing” a Markov blanket.

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