scholarly journals AN EXPERIMENTAL INVESTIGATION OF THE UNIT CHARGE MODEL OF PROTEIN POLYMORPHISM AND ITS RELATION TO THE ESTERASE-5 LOCUS OF DROSOPHILA PSEUDOOBSCURA, DROSOPHILA PERSIMILIS, AND DROSOPHILA MIRANDA

Genetics ◽  
1977 ◽  
Vol 87 (4) ◽  
pp. 717-742
Author(s):  
Gary Cobbs ◽  
Satya Prakash
Keyword(s):  
Small Molecules ◽  
Electrophoretic Mobility ◽  
Drosophila Pseudoobscura ◽  
Average Effect ◽  
Mobility Data ◽  
Step Model ◽  
Charge Model ◽  
Drosophila Persimilis ◽  
The Relationship ◽  
Charge Change

ABSTRACT The relationship between charge changes and electrophoretic mobility changes is investigated experimentally. The charge of several proteins is altered by reaction with small molecules of known structure and the change in electrophoretic mobility is measured. The method of Ferguson plots is used to separate charge and shape components of mobility differences. The average effect of an amino acid charge change on the mobility of the esterase-51.00 allele of Drosophila pseudoobscura is estimated to be 0.046. This estimate is then used to apply the step model of Ohta and Kimura (1973) to electrophoretic mobility data for the esterase-5 locus of D. pseudoobscura and D. miranda. The variation in electrophoretic mobility at this locus was found to be in agreement with the predictions of the step model.

Genetic variation for monomer–dimer equilibria of esterase-5 in Drosophila pseudoobscura, Drosophila persimilis, and Drosophila miranda

1984 ◽  
Vol 26 (3) ◽  
pp. 374-381 ◽  
Author(s):  
David R. Townsend ◽  
Rama S. Singh
Keyword(s):  
Electrophoretic Mobility ◽  
Enzyme Stability ◽  
Good Deal ◽  
The Other ◽  
Drosophila Pseudoobscura ◽  
Closely Related Species ◽  
Speciation Event ◽  
Population Polymorphism ◽  
Drosophila Persimilis ◽  
Close Relatives

Esterase-5 is a highly polymorphic enzyme in Drosophila pseudoobscura and its close relatives. Numerous alleles have been identified by employing a number of physicochemical properties of the enzyme (e.g. electrophoretic mobility, enzyme stability, subunit dimerization, and variation in monomer–dimer equilibrium). Variation in the monomer–dimer equilibrium of esterase-5 leads to differences in electrophoretic mobility of monomers produced by dimers all of which have the same mobility. In this report we have used this criterion to study variation within, as well as between, four closely related species: D. pseudoobscura pseudoobscura, D. pseudoobscura bogotana. D. persimilis, and D. miranda. All lines were characterized for esterase-5 monomer and dimer mobility at a number of gel concentrations and the comparison was made by plotting log10 monomer – dimer mobility as a function of gel concentration. No variation was found within D. p. pseudoobscura or D. p. bogotana but some variation (two distinct alleles) did occur in D. persimilis. Drosophila miranda is segregating for two alleles, one of which is fixed in D. pseudoobscura and the other one is common in D. persimilis. Thus it seems that the variation in monomer–dimer equilibrium is a rather conservative criterion and that the variation in D. miranda is a good deal older than the speciation event(s) which gave rise to D. miranda and the lineage leading to D. pseudoobscura and D. persimilis.Key words: esterase-5, Drosophila pseudoobscura, monomer–dimer equilibrium, population, polymorphism, speciation, electrophoresis.

scholarly journals VARIATION IN BIOCHEMICAL PROPERTIES OF ALLOZYMES OF XANTHINE DEHYDROGENASE IN DROSOPHILA PSEUDOOBSCURA

Genetics ◽  
1980 ◽  
Vol 96 (4) ◽  
pp. 927-938
Author(s):  
David R Wilcox ◽  
Satya Prakash
Keyword(s):  
Substrate Specificity ◽  
Binding Affinity ◽  
Electrophoretic Mobility ◽  
Significant Variation ◽  
Xanthine Dehydrogenase ◽  
Biochemical Properties ◽  
Variant Allele ◽  
Drosophila Pseudoobscura ◽  
Mesa Verde

ABSTRACT Twenty-six D. pseudoobscura strains isogenic for xanthine dehydrogenase alleles from Mesa Verde, Colorado, were tested for differences in the biochemical properties of different allelic forms of xanthine dehydrogenase. No significant differences in binding affinity (Km) or substrate specificity of the enzyme were found. Significant variation among strains, in activity (V  max) and among electromorphs, as well as among strains, in thermolability was found. For the few strains tested, the activity and thermolability differences were shown to co-segregate with the electrophoretic mobility of the variant allele.

The Relationship between Mobility and COVID-19 in Germany: Modeling Case Occurrence using Apple's Mobility Trends Data

2021 ◽  
Author(s):  
Mark David Walker ◽  
Mihály Sulyok
Keyword(s):  
Generalized Additive Models ◽  
Information Criterion ◽  
Additive Models ◽  
Online Data ◽  
German Government ◽  
Explanatory Variables ◽  
Mobility Data ◽  
Community Mobility ◽  
The Relationship ◽  
Potential Use

Abstract Background Restrictions on social interaction and movement were implemented by the German government in March 2020 to reduce the transmission of coronavirus disease 2019 (COVID-19). Apple's “Mobility Trends” (AMT) data details levels of community mobility; it is a novel resource of potential use to epidemiologists. Objective The aim of the study is to use AMT data to examine the relationship between mobility and COVID-19 case occurrence for Germany. Is a change in mobility apparent following COVID-19 and the implementation of social restrictions? Is there a relationship between mobility and COVID-19 occurrence in Germany? Methods AMT data illustrates mobility levels throughout the epidemic, allowing the relationship between mobility and disease to be examined. Generalized additive models (GAMs) were established for Germany, with mobility categories, and date, as explanatory variables, and case numbers as response. Results Clear reductions in mobility occurred following the implementation of movement restrictions. There was a negative correlation between mobility and confirmed case numbers. GAM using all three categories of mobility data accounted for case occurrence as well and was favorable (AIC or Akaike Information Criterion: 2504) to models using categories separately (AIC with “driving,” 2511. “transit,” 2513. “walking,” 2508). Conclusion These results suggest an association between mobility and case occurrence. Further examination of the relationship between movement restrictions and COVID-19 transmission may be pertinent. The study shows how new sources of online data can be used to investigate problems in epidemiology.

scholarly journals Reduction in mobility and COVID-19 transmission

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Pierre Nouvellet ◽  
Sangeeta Bhatia ◽  
Anne Cori ◽  
Kylie E. C. Ainslie ◽  
Marc Baguelin ◽  
...  
Keyword(s):  
Predictive Ability ◽  
Control Measures ◽  
Social Distancing ◽  
Beneficial Effects ◽  
Mobility Data ◽  
Strict Control ◽  
Before And After ◽  
Proxy Measure ◽  
Lower Transmission ◽  
The Relationship

AbstractIn response to the COVID-19 pandemic, countries have sought to control SARS-CoV-2 transmission by restricting population movement through social distancing interventions, thus reducing the number of contacts. Mobility data represent an important proxy measure of social distancing, and here, we characterise the relationship between transmission and mobility for 52 countries around the world. Transmission significantly decreased with the initial reduction in mobility in 73% of the countries analysed, but we found evidence of decoupling of transmission and mobility following the relaxation of strict control measures for 80% of countries. For the majority of countries, mobility explained a substantial proportion of the variation in transmissibility (median adjusted R-squared: 48%, interquartile range - IQR - across countries [27–77%]). Where a change in the relationship occurred, predictive ability decreased after the relaxation; from a median adjusted R-squared of 74% (IQR across countries [49–91%]) pre-relaxation, to a median adjusted R-squared of 30% (IQR across countries [12–48%]) post-relaxation. In countries with a clear relationship between mobility and transmission both before and after strict control measures were relaxed, mobility was associated with lower transmission rates after control measures were relaxed indicating that the beneficial effects of ongoing social distancing behaviours were substantial.

scholarly journals NATURAL SELECTION VS. RANDOM DRIFT: EVIDENCE FROM TEMPORAL VARIATION IN ALLELE FREQUENCIES IN NATURE

Genetics ◽  
1985 ◽  
Vol 111 (3) ◽  
pp. 517-554
Author(s):  
Laurence D Mueller ◽  
Lorraine G Barr ◽  
Francisco J Ayala
Keyword(s):  
Natural Selection ◽  
Strong Evidence ◽  
Allele Frequencies ◽  
Drosophila Pseudoobscura ◽  
Frequency Variation ◽  
Random Drift ◽  
Napa County ◽  
Environmental Variations ◽  
Monthly Sample ◽  
Drosophila Persimilis

ABSTRACT We have obtained monthly samples of two species, Drosophila pseudoobscura and Drosophila persimilis, in a natural population from Napa County, California. In each species, about 300 genes have been assayed by electrophoresis for each of seven enzyme loci in each monthly sample from March 1972 to June 1975. Using statistical methods developed for the purpose, we have examined whether the allele frequencies at different loci vary in a correlated fashion. The methods used do not detect natural selection when it is deterministic (e.g., overdominance or directional selection), but only when alleles at different loci vary simultaneously in response to the same environmental variations. Moreover, only relatively large fitness differences (of the order of 15%) are detectable. We have found strong evidence of correlated allele frequency variation in 13-20% of the cases examined. We interpret this as evidence that natural selection plays a major role in the evolution of protein polymorphisms in nature.

Error assessment of traffic emission estimates using novel mobility datasets.

2021 ◽  
Author(s):  
Johannes Gensheimer ◽  
Alexander J. Turner ◽  
Ankit Shekhar ◽  
Adrian Wenzel ◽  
Frank N. Keutsch ◽  
...  
Keyword(s):  
Local Governments ◽  
Traffic Data ◽  
Traffic Emission ◽  
Trace Gas Emissions ◽  
Mobility Data ◽  
Full Analysis ◽  
Government Data ◽  
The Individual ◽  
Future Work ◽  
The Relationship

<p><span>The COVID-19 pandemic led to widespread reductions in mobility and induced observable changes in the atmosphere. Recent work has employed novel mobility datasets as a proxy for trace gas emissions from traffic, yet there has been little work evaluating these emission numbers. </span></p><p><span>We systematically compare mobility datasets from TomTom and Apple to traffic data from local governments in seven diverse urban and rural regions to characterize the magnitude of errors in emissions that result from using those mobility datasets as a proxy for traffic. We observe differences in excess of 60% between these mobility datasets and local traffic data, which result in large errors in emission estimates. These differences are in part driven by the usage of different baselines and the neglect of seasonality, but mainly they are caused by the individual representations of the datasets. The relationship varies strongly depending on time and region and therefore no general functional relationship between mobility data and traffic flow over all regions can be determined. Future work should be cautious when using these mobility metrics for emission estimates. Further, we use the local government data to identify actual emission reductions from traffic in the range of 7-22% in 2020 compared to 2019 for our study regions. Our full analysis is summarized in Gensheimer et al. (2020).</span></p><p><span>Gensheimer, J., Turner, A., Shekhar, A., Wenzel, A., & Chen, J. (2020). What are different measures of mobility changes telling us about emissions during the COVID-19 pandemic? Earth and Space Science Open Archive, 11. Retrieved from doi: 10.1002/essoar.10504783.1</span></p>

scholarly journals Teacher Leadership Effects on Student Achievement and Student Satisfaction: A Meta Analysis on the Studies Published in Turkey and USA

2019 ◽  
Vol 21 (3) ◽  
Author(s):  
ŞENGÜL UYSAL ◽  
YILMAZ SARIER
Keyword(s):  
Student Achievement ◽  
School Improvement ◽  
Student Satisfaction ◽  
Teacher Leadership ◽  
Meta Analysis ◽  
Average Effect ◽  
Leadership And Student Achievement ◽  
Direct And Indirect Impacts ◽  
Indirect Impacts ◽  
The Relationship

Teacher leadership has grown in importance over the past decades and the growing interest results in the studies presenting direct and indirect impacts on school improvement processes and outcomes. The purpose of this study was to examine the effect of teacher leadership on student achievement and student satisfaction. The methodology involved an analysis of 22 published studies of the relationship between teacher leadership and student achievement with student satisfaction. The meta-analysis involved a comparison of the effects of teacher leadership on student achievement and student satisfaction in Turkey and USA. The results indicated that the average effect of teacher leadership on student achievement is modest and positive and it is strong and positive on student satisfaction. Comparing the countries, in Turkey the average effect of teacher leadership on student satisfaction is much stronger than it is in USA.

scholarly journals A Simple Method to Determine Critical Coagulation Concentration from Electrophoretic Mobility

2020 ◽  
Vol 4 (2) ◽  
pp. 20 ◽  
Author(s):  
Marco Galli ◽  
Szilárd Sáringer ◽  
István Szilágyi ◽  
Gregor Trefalt
Keyword(s):  
Electrophoretic Mobility ◽  
Dlvo Theory ◽  
Computational Method ◽  
Particle Aggregation ◽  
Critical Coagulation Concentration ◽  
Simple Method ◽  
Interparticle Forces ◽  
Mobility Data ◽  
Key Parameter ◽  
Multivalent Electrolytes

Critical coagulation concentration (CCC) is a key parameter of particle dispersions, since it provides the threshold limit of electrolyte concentrations, above which the dispersions are destabilized due to rapid particle aggregation. A computational method is proposed to predict CCC values using solely electrophoretic mobility data without the need to measure aggregation rates of the particles. The model relies on the DLVO theory; contributions from repulsive double-layer forces and attractive van der Waals forces are included. Comparison between the calculated and previously reported experimental CCC data for the same particles shows that the method performs well in the presence of mono and multivalent electrolytes provided DLVO interparticle forces are dominant. The method is validated for particles of various compositions, shapes, and sizes.

Light intensity as a factor in the choice of an oviposition site by Drosophila pseudoobscura and Drosophila persimilis

1983 ◽  
Vol 25 (4) ◽  
pp. 370-377 ◽  
Author(s):  
Dennis J. Wogaman ◽  
Marvin B. Seiger
Keyword(s):  
Light Intensity ◽  
Genetic Variability ◽  
Sibling Species ◽  
Light Response ◽  
Drosophila Pseudoobscura ◽  
Isofemale Lines ◽  
Sympatric Populations ◽  
Allopatric Populations ◽  
Behavioral Differentiation ◽  
Drosophila Persimilis

Light preferences for ovipositing of the sibling species Drosophila pseudoobscura and D. persimilis were measured in a multichoice chamber. Behavioral differentiation was found among sympatric populations of D. pseudoobscura and D. persimilis and between allopatric populations of D. pseudoobscura. Differences among isofemale lines within populations indicated genetic variability for the behavior. Both D. pseudoobscura populations were less fecund in a uniform light environment than in the multichoice environment while D. persimilis showed no difference in fecundity in the two environments. The patterns for general photoresponse and ovipositional light response were shown to be different for each population. Thus, the motivation to oviposit may affect photopreference differentially in each population.

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