On the frequency of Friday the thirteenth

2021 ◽  
Vol 105 (563) ◽  
pp. 222-225
Author(s):  
P. Stanley
Keyword(s):  
Graphical Technique ◽  
Full Day ◽  
Independent Confirmation ◽  
New Look

This article begins with a new look at earlier work on this topic and continues with the presentation of a graphical technique for the determination of the months of a year for which the 13th is a Friday.It might be thought that the likelihood of the 13 th day of a month being a Friday is the same as that of the 13th being any other day, but this is not so. The full day/date repeat cycle is 400 years, this being the interval between century years which are leap years. The outcome of an extraordinary counting exercise some 50 years ago by a 13-year-old Eton schoolboy, S. R. Baxter [1, 2], was to show that, over this period, the 13th of a month will be a Friday at least once more than any other day. Of necessity, Baxter’s calculation was intricate and an independent confirmation was undertaken as a matter of interest. The 400-year period beginning 1 March 2014 was considered. The work is described in four stages.

Graphical determination of specific activity, binding constants, and antibody-site concentrations for radioimmunoassays, with application to thymopoietin.

1980 ◽  
Vol 26 (6) ◽  
pp. 718-723
Author(s):  
F H Verhoff ◽  
P J Lisi ◽  
C D Fischer ◽  
J W Teipel ◽  
G Goldstein ◽  
...  
Keyword(s):  
Binding Sites ◽  
Specific Activity ◽  
Binding Constants ◽  
Experimental Information ◽  
Antibody Binding ◽  
Displacement Analysis ◽  
Additional Information ◽  
Graphical Technique ◽  
Materials Used

Abstract A graphical procedure for determining the specific activity of radiolabeled ligands has been developed for use with radioimmunoassays. Although with this procedure we utilize the same experimental information required for displacement analysis, we are also able to determine both the specific activity and the binding constants of the labeled and unlabeled materials without assuming that these constants are equal; the concentration of antibody-binding sites can also be calculated. Thus, this graphical technique permits calculation of additional information without additional experimentation. We applied this procedure to the labeled materials used in a thymopoietin assay, testing two different preparations of radiolabeled material, and saw negligible differences between the two. The specific activity determined from the displacement analysis correlated well with that calculated by the graphical procedure.

Determination of the apparent transport constants for urate absorption in the rat proximal tubule

1981 ◽  
Vol 240 (5) ◽  
pp. F406-F410
Author(s):  
S. C. Sansom ◽  
H. O. Senekjian ◽  
T. F. Knight ◽  
H. Babino ◽  
D. Steplock ◽  
...  
Keyword(s):  
Reflection Coefficient ◽  
Proximal Tubule ◽  
Continuous Flow ◽  
Active Component ◽  
Solvent Drag ◽  
Perfusion Solution ◽  
Saturation Kinetics ◽  
Rat Proximal Tubule ◽  
Independent Confirmation

Using continuous-flow luminal microperfusion techniques, the influence of the intraluminal urate concentration on urate absorption was determined in the rat proximal tubule. When the estimated contribution of passive permeation was accounted for, the “active” component of urate absorption demonstrated saturation kinetics. The apparent Km was 0.17 mM and the Vmax 0.31 pmol.min-1.mm-1. These transport constants were similar when derived from either a water-absorbing or steady-state equilibrium perfusion solution. The reflection coefficient was determined in studies employing the techniques of simultaneous capillary and luminal microperfusion. Both perfusion solutions contained p-chloromercuribenzoate to inhibit active urate transport. In the presence or absence of an osmole gradient imposed across the tubule, the reflection coefficient for urate averaged 0.94. These studies provide evidence that urate absorption in the rat proximal tubule is a carrier-mediated process. They also provide independent confirmation of the passive flux coefficient derived in prior studies. Finally, the results suggest that solvent drag would have little effect on urate absorption.

Determination of ground constants of permafrost terrains by an electromagnetic method

1976 ◽  
Vol 13 (3) ◽  
pp. 429-441 ◽  
Author(s):  
Ajit K. Sinha
Keyword(s):  
Mutual Coupling ◽  
Coupled System ◽  
Generalized Solution ◽  
Transverse Magnetic ◽  
Magnetic Dipoles ◽  
System A ◽  
Harmonic Currents ◽  
The Earth ◽  
Graphical Technique

The generalized solution of the scattering of electromagnetic fields by an n-layer earth in the presence of oscillating magnetic dipoles carrying harmonic currents has been obtained. The solutions are valid for all frequency ranges and for arbitrary parameters of the n-layer earth. The results have been expressed in terms of six infinite integrals, four of which depend on the transverse electric modes and the rest on the transverse magnetic modes. These solutions have been used to obtain the generalized expressions for the mutual coupling ratios for five coil systems, most often used in the geophysical industry.Using the solutions, a study has been made on the relative performance of the five coil systems for mapping permafrost terrains by multifrequency techniques, assuming the earth to be a homogeneous lossy dielectric, which may be a valid model in winter. It has been observed that the responses in all five coil systems are quite similar, but the magnitude of the response is largest in the horizontal coplanar system. A graphical technique of obtaining the resistivity and dielectric constant of the ground from the mutual coupling ratios has also been described. The results would be useful for designing portable multifrequency e.m. dipole systems for the detection and delineation of permafrost at high latitudes. The inclined, parallel, null-coupled system comes next in order of preference for the mapping of permafrost terrain, followed by the vertical coplanar and the perpendicular systems.

Three-Dimensional Variation Diagrams for Control of Calculations in Optimum Design

1967 ◽  
Vol 89 (3) ◽  
pp. 391-397 ◽  
Author(s):  
R. C. Johnson
Keyword(s):  
Optimum Design ◽  
Mechanical Design ◽  
Three Dimensional ◽  
Diagram Technique ◽  
General Technique ◽  
Variation Diagram ◽  
Graphical Technique ◽  
Dimensional Variation ◽  
Torsion Bar

This paper presents and illustrates a graphical technique for the control of calculations in the procedure of optimum mechanical design. This three-dimensional variation diagram technique minimizes the number of calculations required for the determination of the optimum design, and the general technique is applicable to many problems. Specific practical examples are given for the optimum design of a torsion bar and for the optimum design of a gearset.

A three-dimensional graphical method for shear strain analysis

1994 ◽  
Vol 29 (4) ◽  
pp. 263-266
Author(s):  
S E-D Taher ◽  
A A Almusallam
Keyword(s):  
Graphical Method ◽  
Mathematical Formulation ◽  
Three Dimensional ◽  
Strain Analysis ◽  
Graphical Methods ◽  
Strain Components ◽  
Graphical Technique ◽  
Shearing Strain ◽  
Original Construction

The efficiency of graphical methods for strain analysis depends merely on its simplicity and accuracy. For most strain definitions, the Mohr circle has proved to be the most powerful graphical technique. Unfortunately, its three-dimensional form has limitations concerning the determination of the shearing strain components on a general oblique plane. In this paper, the various deformation quantifiers and the existing extensions to Mohr's method which account for its drawbacks are briefly reviewed. A novel proposal to be appended to Mohr's original construction, allowing its complete generality, is given. It has the form of a simplified complementary triangular construction. A mathematical formulation of the suggested graphical techniques on the basis of Cauchy's formula and vector analysis is carried out.

On-sky verification of the 6-h periodic basic angle variations of the Gaia satellite

2017 ◽  
Vol 12 (S330) ◽  
pp. 231-232
Author(s):  
Shilong Liao ◽  
Mario G. Lattanzi ◽  
Alberto Vecchiato ◽  
Zhaoxiang Qi ◽  
Mariateresa Crosta ◽  
...  
Keyword(s):  
Systematic Errors ◽  
Precise Determination ◽  
Accurate Estimation ◽  
A Value ◽  
Full Day ◽  
Astrometric Data

AbstractA Basic Angle (BA) of 106.5° separates the view directions of Gaia's two fields of view (FoV). A precise determination of the BA variations (BAV) is essential to guarantee a correct reconstruction of the global astrometric sphere, as residual systematic errors would result in, e.g., a bias in the parallaxes of the final Gaia catalog. The Basic Angle Monitoring (BAM) device, which provides a reliable and accurate estimation of BAV, shows that there exists a ~1 mas amplitude, 6-h period BA oscillation. It's essential to verify to what extent this signal is caused by real BAV, or is at least in part an effect of the BAM device itself. Here, we propose an astrometric on-sky approach to re-determine the 6-h periodic BAV. The results of this experiment, which treated a full day (17 Oct 2016) of Gaia astrometric data, recover a value for the 6-h oscillation of 1.856±0.857 mas. This is consistent, within the errors, with the BAM finding for that day.

Graphical determination of specific activity, binding constants, and antibody-site concentrations for radioimmunoassays, with application to thymopoietin.

1980 ◽  
Vol 26 (6) ◽  
pp. 718-723 ◽  
Author(s):  
F H Verhoff ◽  
P J Lisi ◽  
C D Fischer ◽  
J W Teipel ◽  
G Goldstein ◽  
...  
Keyword(s):  
Binding Sites ◽  
Specific Activity ◽  
Binding Constants ◽  
Experimental Information ◽  
Antibody Binding ◽  
Displacement Analysis ◽  
Additional Information ◽  
Graphical Technique ◽  
Materials Used

Abstract A graphical procedure for determining the specific activity of radiolabeled ligands has been developed for use with radioimmunoassays. Although with this procedure we utilize the same experimental information required for displacement analysis, we are also able to determine both the specific activity and the binding constants of the labeled and unlabeled materials without assuming that these constants are equal; the concentration of antibody-binding sites can also be calculated. Thus, this graphical technique permits calculation of additional information without additional experimentation. We applied this procedure to the labeled materials used in a thymopoietin assay, testing two different preparations of radiolabeled material, and saw negligible differences between the two. The specific activity determined from the displacement analysis correlated well with that calculated by the graphical procedure.

scholarly journals Persepsi Siswa Tentang Full Day School Terhadap Hasil Belajar Geografi IPS Kelas XI SMA Negeri 5 Kabupaten Luwu

LaGeografia ◽  
2019 ◽  
Vol 17 (2) ◽  
pp. 64
Author(s):  
Ningsi Anggraini
Keyword(s):  
Multivariate Analysis ◽  
Student Learning ◽  
Learning Outcomes ◽  
Student Learning Outcomes ◽  
Day School ◽  
Coefficient Of Determination ◽  
Ex Post ◽  
Ex Post Facto ◽  
Full Day

This study aims to find out: 1) Application of students about full day school; 2) student learning outcomes; 3) students' application of full day school to learning outcomes. This research is an ex post facto research. The independent variable is the application of students about full day school and the dependent variable is student learning outcomes. The population of class XI IPS students amounted to 86 students, the sample was taken 100%, namely 86 students. Data collection through observation, questionnaires, and documentation of students' final grades. Data analysis used descriptive and inferential analysis of Product Moment correlation, simple liner regression and multivariate analysis. The results of the study show that: 1) the application of full day school has a percentage of 42.36%, which is quite good; 2) student learning outcomes have a percentage of 47.67% including very good categories; 3) the results of the multivariate analysis showed that the full school variable had a significant effect on learning outcomes with a significant 0.00 <0.05. This meant that Ha was accepted and Ho was rejected. This means that the better the implementation of full school, the better the student learning outcomes and vice versa. This can be shown by the equation Y = 35.840 + 0.601X with a correlation coefficient of 0.883 and a coefficient of determination of 0.78. This figure shows that the fullday school system affects 78% of students' geography learning outcomes, while the remaining 22% is affected by other factors not examined in this study.

scholarly journals Social optimal shifts and fares of taxi services

2016 ◽  
Author(s):  
Josep Maria Salanova Grau ◽  
Miquel Estrada Romeu
Keyword(s):  
Time Frame ◽  
Access Time ◽  
Fleet Size ◽  
Time Period ◽  
Decision Variables ◽  
The One ◽  
Vehicle Travel Time ◽  
Generalized Cost ◽  
Full Day

This paper presents a mathematical model for supporting the decision and policy making related to the optimal determination of shifts and fares of taxi services in a major city. The model is based on the system’s generalized cost function and uses continuous approximations and geometric probabilities for estimating the key performance indicators of the taxi market, which are waiting and access time for the customers (in-vehicle travel time does not depend on the offer side) and benefits for the drivers. The model is based on an econometric model with the inclusion of an elastic demand, which allows the estimation of the optimal values for the two decision variables of the problem: fare structure and the taxi fleet size. The model also accounts for a full-day time period instead of the one-hour time frame models used in most of the taxi models, which allows for providing insights on the daily duration and distribution of the shifts that should be defined by the policy makers.DOI: http://dx.doi.org/10.4995/CIT2016.2016.3254

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