Variable Degree Of Correlation Research Articles

A correlation of the measurement techniques and their outputs in the study of the subnational level of politics

Abstract At the beginning of the third decade of the 21st century, the role and value of subnational research in comparative political science are further strengthened, given that the political life of society is moving in two interdependent directions: localisation and internationalisation. Instead, the specifics of the subnational topic contribute to changes and innovations in the implementation of various methodological techniques in the study of subnational units and their structural elements. However, the question of correlating outputs of techniques – objective and subjective – still remains unresolved, and therefore actualises the following formulation: how they appear equivalent in the practical plane, as their theoretical context is illustrated balanced within equivalence in spatial research politics on a subnational scale. In other words, whether the results of each technique are approximate or distinctive from each other from the point of view of the final situation. In the article, a variable degree of correlation has been demonstrated between both techniques and also a hypothesis has been presented about the nature and type of such interactions on the example of three cases (Transcarpathian, Lviv and Chernivtsi regions) in Ukraine in the period 2010–2015.

Microbiological quality of fresh chicken meat products from different farms

The purpose of this paper was to verify the shelf life of fresh chicken meat and offal (grilled chicken, drumsticks, wings, and liver, hearts and gizzards) by determining the microbiological status and the presence of Salmonella bacteria, and the total number of aerobic mesophilic bacteria, Listeria monocytogenes, Escherichia coli and Enterobacteriaceae during the nine days of storage, as well as to determine the correlation between microbial growth of certain bacteria with respect to the test interval and established pH values. The obtained results served to determine farm's rating and classification in relation to the established microbiological status. All products tested in relation to their microbiological quality maintained their hygienic safety within their 7-day shelf life. Only grilled chicken sample remained within the prescribed microbiological criteria limits on the ninth day after production. We established positive correlation with variable degree of correlation between the total number of bacteria isolated from chicken meat samples originating from all farms and the test interval, as well as the positive and negative correlation with variable degree of correlation, and the complete absence of correlation between the total number of bacteria isolated from samples and resulting pH values. Because the highest counts of certain bacteria on the seventh and ninth day for individual farms that were the subject of the study differed even though we examined the same type of product, we carried out a classification of individual farms. The conditions for keeping, transporting and slaughtering broilers, as well as the adequate storage of related products, have a significant impact on the microbiological status, hygienic safety and shelf life of fresh chicken meat.

Abstract 3242: Xenograft dose-response from intra-mouse dose escalation

Abstract Introduction Xenograft response has been shown to hold predictive value for the clinical efficacy of a drug, but growth sensitivity to a drug candidate can vary widely between xenografts models. As the ability to test pre-clinically for broad biological activity across many xenografts models is often resource-limited, in this work we develop a mathematical approach based on evolutionary dynamics to derive dose-response information from a single xenograft tumor. Methods We propose to estimate a dose-response curve of xenograft growth inhibition by treating a single tumor with a series of different dose strengths. Exponential tumor growth rate (GR) may be quickly estimated to determine the inhibition effect of a particular exposure during week-long intervals of constant dose strength. We next considered the possibility of a dose strength ordering effect on tumor growth due to cellular heterogeneity in GR and drug sensitivity within a tumor. To determine to what extent dose history could influence the observed growth inhibition, we developed an evolutionary model of tumor growth for a heterogeneous population of cancer cells with joint-distributed clonal GR and drug sensitivities, and simulated tumor response to treatment for distributions having variable degrees of correlation. Finally, we tested the ability to estimate dose-response curves from single tumors in vivo compared to the typical method of assessing drug effect based on multiple dose-groups. Results For the three possible orders of dosing three different treatment strengths, we found that the simulated study design with escalating dose intervals lead to the least error compared to assessing each dose in a separate tumor. Additionally, the discrepancy between the growth inhibition effects of different dose orders peaks when the correlation between GR and drug sensitivity decreases to negative. We then show that this study design allows efficient, accurate estimation of the range of dose-responses in a broad set of simulated tumor types (e.g., fast-growing and sensitive, or slow-growing and insensitive). An in vivo dose-response study validates the estimation of dose-response curves from a single xenograft by comparing favorably with the single dose per mouse method. Conclusions The mathematical approach described here allows efficient estimation of a dose-response curve for a xenograft model using a single tumor. By reducing the resources required to determine the response of a single model, a molecule's anticancer effect can be tested against a larger sample of tumor types pre-clinically. A more accurate picture of a drug candidate's broad biological activity will allow for greater confidence in translational projections of clinical efficacy. Citation Format: Andrew Chen, Christopher J. Zopf, Jing-Tao Wu, Wen Chyi Shyu, Arijit Chakravarty. Xenograft dose-response from intra-mouse dose escalation. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3242. doi:10.1158/1538-7445.AM2015-3242

A simple framework for modelling the photochemical response to solar spectral irradiance variability in the stratosphere

Abstract. The stratosphere is thought to play a central role in the atmospheric response to solar irradiance variability. Recent observations suggest that the spectral solar irradiance (SSI) variability involves significant time-dependent spectral variations, with variable degrees of correlation between wavelengths, and new reconstructions are being developed. In this paper, we propose a simplified modelling framework to characterise the effect of short term SSI variability on stratospheric ozone. We focus on the pure photochemical effect, for it is the best constrained one. The photochemical effect is characterised using an ensemble simulation approach with multiple linear regression analysis. A photochemical column model is used with interactive photolysis for this purpose. Regression models and their coefficients provide a characterisation of the stratospheric ozone response to SSI variability and will allow future inter-comparisons between different SSI reconstructions. As a first step in this study, and to allow comparison with past studies, we take the representation of SSI variability from the Lean (1997) solar minimum and maximum spectra. First, solar maximum-minimum response is analysed for all chemical families and partitioning ratios, and is compared with past studies. The ozone response peaks at 0.18 ppmv (approximately 3%) at 37 km altitude. Second, ensemble simulations are regressed following two linear models. In the simplest case, an adjusted coefficient of determination R2 larger than 0.97 is found throughout the stratosphere using two predictors, namely the previous day's ozone perturbation and the current day's solar irradiance perturbation. A better accuracy (R2 larger than 0.9992) is achieved with an additional predictor, the previous day's solar irradiance perturbation. The regression models also provide simple parameterisations of the ozone perturbation due to SSI variability. Their skills as proxy models are evaluated independently against the photochemistry column model. The bias and RMS error of the best regression model are found smaller than 1% and 15% of the ozone response, respectively. Sensitivities to initial conditions and to magnitude of the SSI variability are also discussed.

Water and other tetrahedral liquids: order, anomalies and solvation

In order to understand the common features of tetrahedral liquids with water-like anomalies, the relationship between local order and anomalies has been studied using molecular dynamics simulations for three categories of such liquids: (a) atomistic rigid-body models for water (TIP4P, TIP4P/2005, mTIP3P, SPC/E), (b) ionic melts, BeF2 (TRIM model) and SiO2 (BKS potential) and (c) Stillinger–Weber liquids parametrized to model water (mW) and silicon. Rigid-body, atomistic models for water and the Stillinger–Weber liquids show a strong correlation between tetrahedral and pair correlation order and the temperature for the onset of the density anomaly is close to the melting temperature. In contrast, the ionic melts show weaker and more variable degrees of correlation between tetrahedral and pair correlation metrics, and the onset temperature for the density anomaly is more than twice the melting temperature. In the case of water, the relationship between water-like anomalies and solvation is studied by examining the hydration of spherical solutes (Na+, Cl−, Ar) in water models with different temperature regimes of anomalies (SPC/E, TIP4P and mTIP3P). For both ionic and nonpolar solutes, the local structure and energy of water molecules is essentially the same as in bulk water beyond the second-neighbour shell. The local order and binding energy of water molecules are not perturbed by the presence of a hydrophobic solute. In the case of ionic solutes, the perturbation is largely localized within the first hydration shell. The binding energies for the ions are strongly dependent on the water models and clearly indicate that the geometry of the partial charge distributions, and the associated multipole moments, play an important role. However the anomalous behaviour of the water network has been found to be unimportant for polar solvation.

Barium in hemipelagic sediment of the northwest Pacific: Coupling with biogenic carbonate

[1] Geochemical analyses were performed on three cores of hemipelagic sediment from the northwest Pacific Ocean (eastern edge of Shikoku Basin) dating from the last interglacial and glacial periods. The objective of this work is to delineate the relations between excess sedimentary barium [Ba(ex)] content and biogenic opal, carbonate, and organic carbon contents. Calculated Ba(ex) values show variable degrees of correlation with biogenic sediment fractions. The mass accumulation rate (MAR) of Ba(ex) covaries with the MARs of biogenic fractions, and in particular, with the MAR of biogenic carbonate (r2 = 0.68) and TOC (R2 = 0.50). Variable relations between barium and biogenic fractions in hemipelagic sediment provide detailed insight into the behavior of sedimentary barium. It appears that a significant proportion of the barium is affiliated with the carbonate fractions. Based on this strong correlation, carbonate dissolution rates of the last glacial to interglacial periods are estimated. Assuming that the MARs of carbonate and Ba(ex) covary, variation of the Ba/Ca ratio in sediments reflects the extent of postdepositional carbonate dissolution. The record of sedimentary Ba/Ca ratios exhibits striking difference between sediment of the glacial and interglacial periods, with a higher positive correlation during glacial intervals and a lower correlation during interglacial intervals; this pattern is the result of enhanced carbonate dissolution during interglacial times. Sedimentary Ba/Ca ratios may, therefore, be a useful tool for estimating the relative extent of carbonate dissolution. Ba(ex) curves and patterns in sedimentary Ba/Ca ratios resemble the established Pacific carbonate dissolution record (i.e., enhanced dissolution during interglacial times and reduced dissolution during glacial times) as suggested by previous studies. Variations in sedimentary Ba/Ca ratios strongly support an interpretation of pronounced glacial-interglacial fluctuation in carbonate dissolution in the northwest Pacific Ocean. An especially pronounced dissolution event is evident at 75 kyr during the transition interval form interglacial to glacial conditions. This suggests that Ba(ex) may be used as a proxy for evaluating carbonate dissolution in hemipelagic settings, but further study of the association between barium content and carbonate dissolution will be required to confirm this.

Modelling the effects of AIDS on gonorrhea epidemiology

A dramatic decline in gonorrhea has been observed in some American homosexual communities since the advent of AIDS. It has been suggested that this decline is a good indicator of voluntary behavioural change in response to the threat of AIDS. A model is developed here to assess the effects of gonorrhea epidemiology of removals from the community as a result of AIDS. The model allows for a continuous distribution of sexual partner exchange rate and a variable degree of correlation between the rates of those involved in a partnership. Output of the model using plausible parameter values shows that it is possible to explain most or all of the decline in gonorrhea by sickness and deaths due to HIV/AIDS. Therefore, the decline in gonorrhea should not be automatically accepted as evidence of appropriate behavioural change.

The Relationship between Beam Transmission and Concentration of Suspended Particulate Material in the Neuse River Estuary, North Carolina

Monthly measurements made at 15 stations along the axis of the upper Neuse River estuary show a highly variable degree of correlation between concentration of suspended particulate material (SPM) and attenuation of light (c) as measured by transmissometer. Coefficients of determination along transect lines ranged from 0.12 to 0.93 and calibration slopes ranged from 0.50 to 5.63. When examined on a station-by-station basis, coefficients of determination ranged from 0.21 to 0.96 and calibration slopes ranged from 1.04 to 4.94. Surface calibrations made at individual stations over the full 13-month period were the most consistent of all observations and were considerably better than calibrations made using all of the stations on a given day. Organic content, which can dominate the suspended sediment load during some months, does not appear to explain the variations in reliability of the calibrations. However, an abundance of large aggregates with time-varying size and shape distributions may be partly responsible for variations in optical properties of the sediments, and thus may confound the relationship between SPM and c in the Neuse River estuary. Time-varying calibrations to account for non-negligible changes in optical properties may not suffice in complex estuarine environments where the in situ particle dynamics are poorly understood.

Stochastic melting of the marble cake mantle: evidence from local study of the East Pacific Rise at 12°50′N

Isotopes (Nd, Sr and Pb) and trace elements (REE, Ba, Sr, Rb) have been measured on a set of basaltic glasses from a restricted area (40 × 10 km) at 12°50′N on the East Pacific Rise. The huge variation of incompatible element concentrations (factor 70 for Ba concentrations), and the variable degrees of correlation between element concentrations cannot be explained by usual models of melting and fractional crystallization. A rough correlation between the Ce/Yb ratio and the isotopic ratios favors a “source effect” for the genesis of the glasses. We have developed a model including both partial melting process acting on a heterogeneous mantle source with two components (peridotites and pyroxenites; “marble cake mantle” of Allègre and Turcotte) and fractional crystallization. The purpose of this model is not to obtain values of the four parameters involved (degree of melting in the peridotites, in the pyroxenites, proportion of pyroxenites involved in the melting, degree of fractional crystallization) for each analyzed glass, but to model the whole set of glasses by stochastic genesis and sampling of liquids. We have used the stochastic procedure for the four controlled parameters, currently generating 10, 000 “samples”. Our preferred model for this portion of the East Pacific Ridge is obtained with a degree of melting in the peridotites and in the pyroxenites varying uniformly from 6 to 20%, and from 6 to 50% respectively. The degree of mixing between liquids issued from the two sources varies from 0 to 100%, and the degree of fractional crystallization remains small, without noticeable effect on the concentrations, varying from 0 to 6%.