Regression Graphs Research Articles

Detection of amitraz and malathion resistance in field populations of Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) in Jammu region of India.

Detection of resistance levels against amitraz and malathion in Rhipicephalus (Boophilus) microplus collected from four districts of Jammu region (India) was carried out using the adult immersion test. The regression graphs of probit mortality of ticks plotted against log values of concentration of drugs were utilised for the determination of slope of mortality, lethal concentration for 50% (LC50), 95% (LC95) and resistance factor (RF). On the basis of the data generated on variables (mortality, egg mass weight, reproductive index and percentage inhibition of oviposition) the resistance level was categorised as I, II, III and IV. Out of these four districts, resistance to amitraz was detected at level I in Udhampur (RF=2.81), Jammu (RF=2.53) and Sambaisolates (RF=2.24) whereas Rajouri isolate was found susceptible (RF=1.0). Resistance to malathion was detected at level I in Udhampur (RF=4.01) and Jammu isolates (RF=1.76) whereas Rajouri (RF=0.472) and Samba (RF=0.199) isolates were found susceptible. The data generated on amitraz and malathion resistance status will help in formulatinga tick control strategy in the region.

Estimation of male stature by ulnar length in Madhya Pradesh region by using linear regression analysis

Introduction: Establishment of reliable formula for stature estimation from fragments of bones especially in forensic examination is important for individual identification. Sexual differences in height and of long bones exist so there is need for studies emphasizing quantitative standards of sexual dimorphism in different populations. Limited availability of gender specific studies of stature estimation by using individual bones provide data for forensic identification that led me to study ulna bone to establish a linear regression equation for stature estimation in living adult males of age group 18-26 yrs in Madhya Pradesh region. Material & Methods: Cross sectional study was conducted in Department of Anatomy, Gandhi Medical College, Bhopal (M.P.) on 238 males by using anthropometer and spreading caliper and statistically analyzed. Ulna length were measured independently on right and left sides of each subject with the help of spreading caliper from the tip of olecranon process to the tip of styloid process and vertex to heel height was measured in the standing erect posture with subject looking forward straight to the horizon. Results: Value of correlation coefficient(r) of right ulna with stature was found to be 0.995 and left ulna with stature was 0.997. Regression equations and graphs interpret the height from the ulnar length in males. Conclusion: The regression formula derived will be useful for anatomists, clinician, anthropologists and forensic experts for estimation of the individual stature in Madhya Pradesh region for establishing identity.

Detection of deltamethrin resistance in eggs and larva of Rhipicephalus (Boophilus) microplus

Rhipicephalus (Boophilus) microplus is the most common tick species in India infesting cattle and buffaloes and cause significant economic losses to dairy and leather industries by adversely affecting the milk production and quality of hides. Egg hatch assay and larval packet test were used to evaluate the comparative acaricidal efficacy of the market formulations of deltamethrin, cypermethrin and amitraz on eggs and larval stages of R. (B.) microplus. The regression graphs of probit hatchability, % inhibition of hatching (IH) of eggs and probit mortality were plotted against log concentrations of various acaricides. The results revealed that cypermethrin and amitraz were effective and produced complete inhibition of hatching. LC95 values of cypermethrin and amitraz calculated by larval packet test were estimated to be 244.91 ppm and 369.83 ppm, respectively. On the other hand, deltamethrin failed to completely inhibit the hatching. LC95 values by egg hatch assay and larval packet test were estimated to be 42.27 ppm and 39.36 ppm, respectively. The data on field status of acaricide resistance from the area with diversified animal genetic resources will be helpful to adopt suitable strategy to overcome the process of development of resistance in ticks.

Selection of the best lines of sugar beet sterility maintainers in terms of potassium content in breeding for improved technological quality of roots

Purpose. To study the variability of potassium content sign in sterility maintainers of sugar beet, establish the correlation with sugar content of roots, select sources of the low content of potassium ions for the improved technological quality of roots.Methods. Genetic and statistical analysis of the genotypic variability of agronomic traits in sterility maintainers, regression analysis. Source material: five sterility maintainer lines.Results. The content of potassium ions in the best sterility maintainer lines of Uladivska RBS origin ranged from 3.5 to 4.1 mg/equivalent per 100 g of raw material that was due to their genotype. The coefficient of variation in lines Ot 1, and Ot 3 was average, while in lines Ot 2 and Ot 4 high, creating an opportunity for inter-line selection. Selections groups of improved agronomic characteristics (root weight, sugar content, reduced content of potassium, sodium, α-amino nitrogen) were completed. A regression model of the interdependence of the signs of potassium content and sugar content was investigated, low correlation coefficients between signs (r = 0,09 ... -0,15) were found. The comparative characteristic in regression graph contrasting the content of potassium ions in sterility maintainer lines was performed.Conclusions. Lines Ot 2 and Ot 1 characterized by low content of potassium ions were selected. They will be involved in the crosses arranged in diallel design as a source of improved features. Selection groups for each of the five O-type lines, which had their potassium, sodium and α-amino nitrogen content significantly reduced were created. Low interdependence of the signs of sugar content and potassium content was found out, which is a genetic feature of breeding materials of Uladivska RBS origin.

Enhanced Biomass Characteristics Index in palm biomass calorific value estimation

Oil palm industry contributes a huge amount of valuable crude palm oil, and simultaneously producing a large quantity of plantation waste or biomass, which will be utilized as fuel. In order to give a clear insight of the energy output estimation from the biomass, a comprehensive study on the physical properties of the biomass: bulk density and moisture content is crucial. In a conventional approach, these properties are obtained through empirical methods on individual sample basis. However, the conventional empirical methods have several drawbacks: (i) require a huge amount of experimental results to construct biomass properties’ curve (ii) data variation affects the accuracy of analysis result. These create a limitation in properties estimation and further affecting the optimum biomass utilization. To tackle this issue, there is a need to search for a direct representation of the properties. A Biomass Characteristics Index (BCI) is proposed to represent the relationship between bulk density and moisture content. A numerical framework is developed to determine the BCI. This index is used to estimate the biomass bulk density and moisture content before the calorific value calculation. A regression graph is plotted to illustrate the relationship among those values with respect to different appearance shapes of biomass. The result shows that different size and shape of biomass has its own specific BCI. The classification of biomass according to its specific BCI can forecast the related bulk density and moisture content. Therefore, it reduces the hassle, especially in terms of time constraint to get those values through conventional empirical method. This will increase the overall biomass operational management efficiency.

The coevolution of innovation and technical intelligence in primates.

In birds and primates, the frequency of behavioural innovation has been shown to covary with absolute and relative brain size, leading to the suggestion that large brains allow animals to innovate, and/or that selection for innovativeness, together with social learning, may have driven brain enlargement. We examined the relationship between primate brain size and both technical (i.e. tool using) and non-technical innovation, deploying a combination of phylogenetically informed regression and exploratory causal graph analyses. Regression analyses revealed that absolute and relative brain size correlated positively with technical innovation, and exhibited consistently weaker, but still positive, relationships with non-technical innovation. These findings mirror similar results in birds. Our exploratory causal graph analyses suggested that technical innovation shares strong direct relationships with brain size, body size, social learning rate and social group size, whereas non-technical innovation did not exhibit a direct relationship with brain size. Nonetheless, non-technical innovation was linked to brain size indirectly via diet and life-history variables. Our findings support 'technical intelligence' hypotheses in linking technical innovation to encephalization in the restricted set of primate lineages where technical innovation has been reported. Our findings also provide support for a broad co-evolving complex of brain, behaviour, life-history, social and dietary variables, providing secondary support for social and ecological intelligence hypotheses. The ability to gain access to difficult-to-extract, but potentially nutrient-rich, resources through tool use may have conferred on some primates adaptive advantages, leading to selection for brain circuitry that underlies technical proficiency.

Pairwise Markov properties for regression graphs

With a sequence of regressions, one may generate joint probability distributions. One starts with a joint, marginal distribution of context variables having possibly a concentration graph structure and continues with an ordered sequence of conditional distributions, named regressions in joint responses. The involved random variables may be discrete, continuous or of both types. Such a generating process specifies for each response a conditioning set that contains just its regressor variables, and it leads to at least one valid ordering of all nodes in the corresponding regression graph that has three types of edge: one for undirected dependences among context variables, another for undirected dependences among joint responses and one for any directed dependence of a response on a regressor variable. For this regression graph, there are several definitions of pairwise Markov properties, where each interprets the conditional independence associated with a missing edge in the graph in a different way. We explain how these properties arise, prove their equivalence for compositional graphoids and point at the equivalence of each one of them to the global Markov property. Copyright © 2016 John Wiley & Sons, Ltd.

Breastfeeding in Nigeria: a systematic review

Breastfeeding confers numerous benefits on babies and mothers. Early initiation, ‘exclusive breastfeeding’ and breastfeeding for at least two years post-delivery are the recommended practices. This study aims to examine the trends of breastfeeding practice in Nigeria by reviewing available published studies. The online databases of PubMed, Science Direct and the Web of Knowledge were searched using relevant terms. Studies identified were screened for eligibility and those that met the inclusion criteria were included in this review. Graphs and regression equations were generated using Microsoft Excel® to illustrate the duration of and trends in, breastfeeding practices in Nigeria. This review adopts the WHO standard definitions for breastfeeding categories. A total of 24 studies met the inclusion criteria but only two of these adopted the standard WHO breastfeeding categories in estimating the rates of breastfeeding. The regression equations and graphs generated show a declining trend in the rates of ‘exclusive breastfeeding’ and an increasing trend in the mean duration of breastfeeding. The rate of ‘any breastfeeding’ was high. Breastfeeding duration varies across Nigeria, a possible reflection of differences in sociocultural practices. Various reasons were cited for discontinuation of breastfeeding, the commonest of these were maternal health problems and the demands of work. Breastfeeding is commonly practiced in Nigeria. However, the rate of ‘exclusive breastfeeding’ is low and declining. It is recommended that future studies on breastfeeding in Nigeria adopt the standard WHO definitions.

First report of ivermectin resistance in field populations of Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) in Punjab districts of India

The larval immersion test (LIT) was used on the progenies of Rhipicephalus (Boophilus) microplus collected from four districts of the Punjab state, India to test the resistance to ivermectin. The regression graphs of probit mortality of larval ticks plotted against log values of increasing concentrations of ivermectin were utilized for the determination of slope of mortality, lethal concentration for 50%(LC50), 95%(LC95), resistance ratios (RR50, RR95) and the resistance levels (RL). Values of the coefficient of determination (R2) for LIT ranged from 0.900 to 0.978, and the RR50 and RR95 values against ivermectin ranged from 2.97 to 8.85 and 2.42 to 8.47, respectively, indicating resistance status in all field isolates. On the basis of RR values, three field isolates (BAT, GUR, HOS) showed level II, whereas PTK isolate showed presence of level I resistance status against ivermectin. This appears to be the first report of ivermectin resistance in R. (B.) microplus from Punjab, India.

Deltamethrin resistance in field populations of Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) in Jammu and Kashmir, India

Detection of resistance levels against deltamethrin in Rhipicephalus (Boophilus) microplus collected from six districts of Jammu and Kashmir (India) was carried out using the adult immersion test. The regression graphs of probit mortality of ticks plotted against log values of concentration of drug were utilised for the determination of slope of mortality, lethal concentration for 50% (LC50), 95% (LC95) and resistance factor (RF). On the basis of the data generated on mortality, egg mass weight, reproductive index and percentage inhibition of oviposition, the resistance level was categorised as I, II, III and IV. Out of these six districts, resistance to deltamethrin at level I was detected in one district (RF = 1.9), at level II in two districts (RF = 7.08-10.07) and at level IV in three districts (RF = 96.08-288.72). The data generated on deltamethrin resistance status will help in formulating tick control strategy in the region.

The Specific Features of Logistic Regression Curves That Can be Used for Classification of Cases and Decision-Making

Introduction Logistic regression analysis is frequently used to estimate the relationships between dichotomized dependent variable and continuous independent variable; however, even an evidence of highly significant relationship could be insufficient for the decision-making. Thorough analysis of event probability growth patterns could be helpful to classify cases and to determine cut-off criterions that could be based on critical points of the graph corresponding to the changes in the velocity of event probability growth per unit of predictive variable. The objective is to study the specific features of logistic regression curves to evaluate those critical points. Materials and Methods A total of 15 logistic regression functions estimated during scientific studies were analyzed. Points in the graph that correspond to the changes in velocity of probability growth per unit of predictive variable were estimated using second, third, and fourth derivatives of estimated logistic regression functions. The calculated values were then used for predictive variables corresponding to zero points of derivatives to calculate the respective probability values applying estimated previous logistic regression function. Finally, the structure of logistic regression graphs was analyzed and divided into several parts as shown in Fig. 1. Results Typical logistic regression curve is shown in Fig. 1. It was revealed that logistic regression function graphs have the same structure. Point A corresponds to zero point of second derivative, the value of corresponding probability is 0.5. B and B1 points correspond to zero values of third derivative, the values of probability are 0, 21132 and 0, 0.788675, respectively. C and C1 correspond to zero points of fourth derivative and the corresponding probability values are 0.091751 and 0.90824, respectively. Up to point C, there is a baseline of the event with a minor velocity of probability growth. Part of the graph (from point B to C) represents the initial increase in velocity of probability growth, while the one from B to B1 represents maximal velocity of probability growth per unit of predictive variable. Conclusions This type of analysis can be applied to decision-making, while it is possible to reveal borders for part of the graph that is indicated as B–C part in Fig. 1. This part of the graph corresponds to the initial acceleration in probability of event growth per unit of predictive variable (e.g., the onset of the disease); consequently, those patients should be put under observation. Further shifts of predictive variable value to the B–B1 part of the graph should be taken under consideration and appropriate treatment should be applied as the velocity of probability growth becomes maximal. The example for this analysis application could be a relationship between low energy vertebra fractures rate and bone density.

Socio-Demographic Determinants for Entrepreneurial Intention of University Students: The Case of University of Gondar Graduating Students

Entrepreneurship is one of the best economic development strategies being a source of job opportunity, promoting balanced regional development, improving the living standard of the common people, ensuring self-reliance and balancing import–export transaction of a given country. Cognizant of these facts, this research examined the entrepreneurial intention of 2011/2012 graduating students of University of Gondar, Ethiopia. Cross-sectional study was conducted through mixed research method with sequential explanatory strategy. The findings of this study were based on information drawn from 310 sample respondents, two discussion sessions with 6 individuals and 10 key informants. Binary logistic regression, Chi-square test, percentage and bar graph have been used. About 56% of graduating students were not entrepreneurially intended. Taking entrepreneurship course, role model occupation, using of learning by doing approach, gender and family work expectation were significant predictors of entrepreneurial intention with Exp (B) of 5.821, 4.167, 2.94, 2.93 and 0.048 respectively. The study recommends that entrepreneurial orientation of the content and methods of teaching, the awareness level of role model and the surrounding community to the nature and role of entrepreneurship should be enhanced.Keywords: entrepreneurial intention, socio-demographic variable and university graduating students

In vitro acaricidal activity of Murraya koenigii (L.) Spreng (Rutaceae) extracts against synthetic pyrethroid-resistant Rhipicephalus (Boophilus) microplus.

Larval packet test was used for detection of resistance status against cypermethrin and deltamethrin, the most commonly used synthetic pyrethroids in Rhipicephalus (Boophilus) microplus collected from Faridkot district, Punjab (India). The slope of mortality, lethal concentration for 50 % (LC50) and resistance levels were determined from the regression graphs of probit mortality of ticks plotted against log values of increasing concentrations of cypermethrin and deltamethrin. Results indicated presence of resistance of levels I and II against cypermethrin (resistance factor (RF) = 2.82) and deltamethrin (RF = 8.44), respectively. Adult immersion test was used to assess the acaricidal activity of aqueous (MLAq), ethanol (MLE), chloroform (MLC), acetone (MLA) and hexane (MLH) extracts of leaves of Murraya koenigii against these synthetic pyrethroid (SP)-resistant engorged adult females of R. (B.) microplus by determination of per cent adult mortality, reproductive index (RI), per cent inhibition of oviposition (%IO) and hatching rate. The per cent mortality caused by various extracts at concentrations ranging from 0.625 to 10.0% varied from 0.0 to 100.0% with maximum per cent mortality of 10.0, 100.0, 70.0, 40.0 and 10.0 recorded against MLAq, MLE, MLC, MLA and MLH, respectively. Among all extracts, the highest acaricidal property against SP-resistant R. (B.) microplus was exhibited by the MLE as it showed the minimum LC50 [95% confidence limit (CL)] values of 2.97% (2.82-3.12%), followed by MLC as 10.26% (8.84-11.91 %) and MLA as 18.22% (16.18-20.52%). The average egg mass weight recorded in live ticks treated with various concentrations of different extracts was lower than the respective control group ticks and was significantly (p < 0.01) lower in ticks treated with MLH extract. However, no significant effect on hatchability of eggs of treated groups when compared to control was recorded. A significant (p < 0.05) decrease in the RI was recorded in MLH extract-treated ticks, and the %IO varied from 0.07 to 34.73% with various extracts and was recorded maximum with highest concentration of MLH. The results of the current study indicate that the extracts of M. koenigii can be used for control of SP-resistant ticks.

Detection of Malathion Resistance in Hyalomma anatolicum anatolicum from Bathinda District, Punjab.

Objective:The resistance status against malathion in Hyalomma anatolicum anatolicum ticks collected from Bathinda district, Punjab, was evaluated by adult immersion test (AIT).Materials and Methods:Technical grade malathion was used for conduction of AIT with 2 min immersion time protocol. The regression graph of probit mortality of ticks was plotted against log values of increasing concentrations of malathion and was utilized for the determination of slope of mortality, LC50, LC95 (95% confidence interval [CI]) and resistance factor (RF). The reproductive parameters of treated ticks viz. egg mass weight, reproductive index (RI), and percentage inhibition of oviposition (% IO) were also studied.Results:The increasing concentration of malathion showed an upward trend in per cent tick mortality. The slope of mortality (95% CI) was 2.489 ± 0.719 (2.489 ± 0.719) and value of goodness of fit (R2) was 0.799. The LC50 (95% CI) and LC95 (95% CI) values were recorded as 9099.2 (8378.6–9881.7) and 41,511.3 (35,060.2–49,149.4) ppm, respectively, with RF as 16.60 indicating level II resistance status. A negative dose-dependent slope of egg mass weight (−91.79 ± 25.15 [−171.8 to −11.76]) was recorded as the survived ticks laid significantly (P = 0.0355) fewer eggs. The mean RI of treated ticks decreased with increasing concentrations of drug and the slope (95% CI) was −0.293 ± 0.059 (−0.482 to −0.105). Further, a dose-dependent significant increase (P = 0.0157) in the mean % IO was recorded in treated ticks.Conclusions:The results of the current study would be useful in the formulation and implementation of effective tick strategies in the region.

Identification of causal effects in linear models: beyond instrumental variables

The instrumental variable (IV) formula has become widely used to address the issue of identification of a causal effect in linear systems with an unobserved variable that acts as direct confounder. We here propose two alternative formulations to achieve identification when the assumptions underlying the use of IV are violated. Parallel to the IV, the proposed formulas exploit the conditional independence structure of a directed acyclic graph and can be obtained via a series of univariate regressions, a feature that renders the results particularly attractive and easy to implement. By exploiting the notion of Markov equivalence, the derivations can also be applied to regression graphs, thereby enlarging the class of models to which the results are of use.

A Convex Pseudolikelihood Framework for High Dimensional Partial Correlation Estimation with Convergence Guarantees

SummarySparse high dimensional graphical model selection is a topic of much interest in modern day statistics. A popular approach is to apply l 1-penalties to either parametric likelihoods, or regularized regression/pseudolikelihoods, with the latter having the distinct advantage that they do not explicitly assume Gaussianity. As none of the popular methods proposed for solving pseudolikelihood-based objective functions have provable convergence guarantees, it is not clear whether corresponding estimators exist or are even computable, or if they actually yield correct partial correlation graphs. We propose a new pseudolikelihood-based graphical model selection method that aims to overcome some of the shortcomings of current methods, but at the same time retain all their respective strengths. In particular, we introduce a novel framework that leads to a convex formulation of the partial covariance regression graph problem, resulting in an objective function comprised of quadratic forms. The objective is then optimized via a co-ordinatewise approach. The specific functional form of the objective function facilitates rigorous convergence analysis leading to convergence guarantees; an important property that cannot be established by using standard results, when the dimension is larger than the sample size, as is often the case in high dimensional applications. These convergence guarantees ensure that estimators are well defined under very general conditions and are always computable. In addition, the approach yields estimators that have good large sample properties and also respect symmetry. Furthermore, application to simulated and real data, timing comparisons and numerical convergence is demonstrated. We also present a novel unifying framework that places all graphical pseudolikelihood methods as special cases of a more general formulation, leading to important insights.

Fenvalerate resistance status in Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) from Punjab, India.

Larval packet test was used for evaluating the resistance levels in Rhipicephalus (Boophilus) microplus collected from different districts of central plain zone of Punjab state, India against fenvalerate. The regression graphs of probit mortality of larvae plotted against log values of progressively increasing concentrations of fenvalerate were utilized for the estimation of lethal concentration for 50% (LC50) and 95% (LC95) values against various field isolates of R. (B.) microplus. The slope of mortality (95% confidence levels) varied from 0.730±0.097 (0.419-1.043) to 1.455±0.281 (0.558-2.352) and the value of R(2) varied from 0.881 to 0.997. From the regression equation the values of LC50 and LC95 were recorded in range of 184.39-1,338.01 and 3,253.33-112,706.26ppm, respectively. Among the various tick isolates resistance factors in range of 1.56-54.34 were determined and all field isolates studied were found resistant against fenvalerate. Two field isolates (Jalandhar and Ludhiana) showed level I resistance; three (Patiala, Fatehgarh Sahib and Amritsar) showed level II and Kapurthala isolate showed level IV resistance. The data generated on fenvalerate resistant status will help in judicious use of the drug and formulation of effective tick control strategy for the region.

Biomass Characteristics Index: a Numerical Approach in Palm Bio-energy Estimation

Oil palm industry contributes a huge amount of valuable crude palm oil, also directly produces large quantity of plantation waste or biomass if it will be utilized as a fuel. In order to give a clear insight of the energy output estimation from the biomass, a comprehensive study on the physical properties of the biomass: bulk density and moisture content is crucial. In conventional approach, these properties are obtained through empirical methods on individual sample basis. There are several drawbacks from the conventional empirical methods: (i) need a huge amount of experimental results to construct biomass properties’ curve (ii) data variation affects the accuracy of analysis result. These create a limitation in properties estimation and then further affect the optimum biomass utilization. To tackle this issue, there is a need to search for a direct representation of the properties. A Biomass Characteristics Index (BCI) is proposed to represent the relationship between bulk density and moisture content. A numerical framework is developed to determine the BCI. This index is used to estimate the biomass bulk density and moisture content before the calorific value calculation. A regression graph is plotted to illustrate the relationship among those values with respect to different appearance shapes of biomass. The result shows that different size and shape of biomass has its own specific BCI. The classification of biomass according to its specific BCI can forecast the related bulk density and moisture content. Therefore, it reduces the hassle and time constraint to get those values through conventional empirical method. This will increase the overall biomass operational management efficiency.

Esterase mediated resistance against synthetic pyrethroids in field populations of Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) in Punjab districts of India

Detection of resistance levels against cypermethrin and deltamethrin, the most commonly used synthetic pyrethroids (SP), in Rhipicephalus (Boophilus) microplus collected from thirteen districts of Punjab (India) was carried out using adult immersion test. The regression graphs of probit mortality of ticks plotted against log values of concentrations of drugs were utilized for the determination of slope of mortality, lethal concentration for 50% (LC50), 95% (LC95) and resistance factor (RF). On the basis of the data generated on variables (mortality, egg mass weight, reproductive index and percentage inhibition of oviposition) the resistance levels were categorized. Against cypermethrin RFs of 1.48–11.22 were recorded in 12 isolates whereas, one isolate was susceptible. Resistance factors against deltamethrin were 2.4–38.54 and all 13 isolates were found to be resistant. Quantitative analysis of general esterase activity (measured by the production of the metabolite naphthol) revealed a range of 3.34±0.30–13.75±1.33 and 1.31±0.15–8.09±0.68μmol/min/mg protein for α and β-esterase activity, respectively in different field isolates. Further, multiple pairwise comparisons of the mean values with susceptible strain (Tukey, P=0.05) revealed significant elevated levels of both α-esterase and β-esterase in nine tick isolates resistant to both deltamethrin and cypermethrin. The data generated on acaricide resistant status and esterase mediated mechanism in ticks will help in formulating tick control strategy for the region.

Power-use in cooperative competition: A power-dependence model and an empirical test of network structure and geographic mobility

Although the social exchange paradigm has produced a vibrant research program, the theoretical tradition is rarely used to model the structure of social networks outside of experiments and simulations. To address this limitation, we derive power-dependence predictions about network structure and geographic mobility—the outcomes of power-use—and test these predictions using complete data on competition networks and travel schedules among amateur sports teams. Poisson regression and exponential random graph models provide strong support for our predictions. The findings illustrate exchange dynamics in which status resources desired by teams, coupled with the availability of geographically proximal alternatives, create power and dependence that dictate where and with whom teams compete. Although evidence supports Georg Simmel’s classic proposition that networks form on the basis of values and propinquity, we show that this complex dynamic is conditional on power and dependence. We conclude by discussing implications and directions for future research.