Similar Definitions Research Articles

The concept of difficult-to-treat disease in rheumatology: where next?

New pathogenesis-based therapeutics and evidence-based consensus treatment recommendations, often with predefined treatment goals, have remarkably improved outcomes across many chronic diseases. However, a clinically significant subgroup of patients responds poorly to interventions and show a progressive decline in the disease trajectory, which poses an increasing health-care challenge. Difficult-to-treat approaches exist in several areas of medicine and the need for similar definitions has recently also emerged in rheumatology. The term difficult-to-treat refers not only to patients with pathology-driven, treatment-refractory disease, but also implicates multiple other factors that can contribute to patients being in this state, including having few treatment options, misdiagnosis, and coincident psychosocial factors. Therefore, the difficult-to-treat state requires a comprehensive, holistic, multidisciplinary approach that considers the specific characteristics of each disease and the personalised needs of the patient. In this Personal View, we provide an overview of the different aspects of the concept of difficult-to-treat disease, highlight its advantages, and propose the importance of incorporating this concept more widely in the design of rheumatological treatment strategies.

The Structure of Bit-String Similarity Networks.

We study the structural properties of networks formed by random sets of bit strings-namely the ordered arrays of binary variables representing, for instance, genetic information or cultural profiles. Two bit strings are connected by a network link when they are sufficiently similar to each other, i.e., when their Hamming distance is below a certain threshold. Using both analytical and numerical techniques, we determine the degree distribution and the conditions for the existence of a giant component in this kind of network. In addition, we analyze their clustering, assortativity, and mean geodesic distance. We show that these properties combine features specific to random networks with characteristics that derive from the Hamming metrics implicit in the definition of similarity between bit strings.

A Consistent Lack of Consistency: Definitions, Evidentiary Expectations and Potential Use of Meaningful Change Data in Clinical Outcome Assessments Across Stakeholders. Results from a DIA Working Group Literature Review and Survey.

Clinical outcome assessments (COAs) measure how patients feel or function and can be used to understand which patients experience benefits of treatment and which do not. Interpretation of COA data is influenced by how meaningful change is defined. We aimed to compare how different stakeholders define, assess, and use meaningful change for decisions that impact patients. A targeted literature review was undertaken in July 2021 using Medline, Embase, online grey literature search engines, and stakeholder organization websites. Additionally, a stakeholder survey on meaningful change was fielded between March and June 2023. Both quantitative and qualitative methods were used to analyze responses and identify key themes. The literature review resulted in 86 references. These revealed different approaches to define, measure and validate meaningful change. There were 248 survey responses. Many respondents felt the terminology and methods for defining meaningful change are confusing. Respondents also emphasized the importance of distinguishing within-patient and between-group change, and defining meaningfulness from the patient perspective (most patients and caregivers do not share a similar definition of meaningfulness as their healthcare professionals). Four key recommendations for defining, establishing, and interpreting meaningful change estimates for COAs are: (1) Be clear on the type of "meaningful change" that is discussed or needed for a COA, (2) Ensure the "patient voice" is informing meaningful change estimates/definitions, (3) Acknowledge that a meaningful change estimate for a COA may differ between populations, diseases, and disease states, and (4) Disseminate data in a way that reduces ambiguity.

Enhancing interprofessional ward rounds by identifying factors associated with low satisfaction and efficiency: a quantitative and qualitative national survey of Swiss healthcare professionals.

Interprofessional ward rounds are a cornerstone of patient-centred care for medical inpatients and offer opportunities to discuss and coordinate patient treatment and further management. We aimed to identify factors associated with lower satisfaction and efficiency of interprofessional ward rounds, as reported by physicians and nurses. An anonymous Swiss nationwide online survey of physicians and nurses was conducted in 28 Swiss internal medicine inpatient departments between 9 August and 19 October 2023. Analyses were conducted from November to December 2023. The primary outcome was physicians' and nurses' perceived lower satisfaction with ward rounds, which was assessed using visual analogue scales ranging from 0 to 10, with lower satisfaction defined as scores below the median. The main secondary outcome was perceived lower efficiency using a similar definition. Qualitative analysis was performed through inductive thematic analysis. The survey had a response rate of 21.6% (547/2530). Of the 547 physicians and nurses included in the final analysis, the median satisfaction was 7 points (interquartile range [IQR] 6-8). A total of 61% of physicians (156/254) and 76% of nurses (224/293) reported lower satisfaction. Lower satisfaction was reported significantly more frequently by nurses (adjusted odds ratio [OR] 2.33, 95% confidence interval [CI] 1.58-3.43; p ≤0.001) and female team members (adjusted OR 1.95, 95% CI 1.32-2.9; p <0.01). The median perceived efficiency of ward rounds was 7 points (IQR 5-8), and the nursing profession was associated with lower perceived efficiency (adjusted OR 1.95, 95% CI 1.3-2.93; p <0.01). Adherence to in-house guidelines for ward rounds was associated with satisfaction (adjusted OR for lower satisfaction 0.25, 95% CI 0.16-0.39; p <0.001) and perceived efficiency (adjusted OR for lower efficiency 0.27, 95% CI 0.17-0.43; p <0.001). Both physicians and nurses preferred to perform ward rounds as part of an interprofessional team. The qualitative analysis of the data revealed a preference for structured interprofessional ward rounds and the active involvement of nurses. This survey revealed an overall high preference for interprofessional ward rounds. In addition, we identified several factors that were associated with lower satisfaction and efficiency. Structured in-house protocols for ward rounds may increase the satisfaction and efficiency of interprofessional collaboration during ward rounds.

From Natural to Artificial: The Transformation of the Concept of Logical Consequence in Bolzano, Carnap, and Tarski

Our standard model-theoretic definition of logical consequence is originally based on Alfred Tarski’s (1936) semantic definition, which, in turn, is based on Rudolf Carnap’s (1934) similar definition. In recent literature, Tarski’s definition is described as a conceptual analysis of the intuitive ‘everyday’ concept of consequence or as an explication of it, but the use of these terms is loose and largely unaccounted for. I argue that the definition is not an analysis but an explication, in the Carnapian sense: the replacement of the inexact everyday concept with an exact one. Some everyday intuitions were thus brought into a precise form, others were ignored and forgotten. How exactly did the concept of logical consequence change in this process? I suggest that we could find some of the forgotten intuitions in Bernard Bolzano’s (1837) definition of ‘deducibility’, which is traditionally viewed as the main precursor of Tarski’s definition from a time before formalized languages. It turns out that Bolzano’s definition is subject to just the kind of natural features—paradoxicality of everyday language, Platonism about propositions, and dependence on the external world—that Tarski sought to tame by constructing an artificial concept for the special needs of mathematical logic.

Understanding of income and race disparities in hurricane evacuation is contingent upon study case and design

As hurricanes become more frequent and destructive, understanding evacuation decision-making is crucial to refining disaster response strategies. Several studies have explored how socioeconomic characteristics such as income and race impact evacuation behavior. Most of these studies focus on a single hurricane event with the geographic extent limited to one or two states, each using a distinct study design, making them difficult to compare. This raises the question of whether findings from isolated cases can be generalized across different hurricane scenarios and geographical settings under a similar study design and consistent parameter definitions. To address this gap, in this study, we conduct a comparative analysis to understand income and racial disparity across multiple hurricane events. The results indicate that, even with a consistent study design, disparities in evacuation among different socioeconomic groups vary on a case-by-case basis. Furthermore, we show that the study design significantly impacts the observed trends within a single case. This highlights the importance of avoiding generalized conclusions based on limited case studies. It further emphasizes how flawed study designs may fail to capture the complexities of real-world behaviors, thereby leading to suboptimal or ineffective policy recommendations or designs.

Speed excess and total acceleration: a kinematical approach to entanglement

Abstract The total variance of a spin state is defined as the average of the variances of spin projection measurements along three orthogonal axes. We show that this quantity also gives the squared rotational speed of the state in projective space, averaged over all rotation axes. We compute the addition law, under system composition, for this quantity and find that, in the case of separable states, it is of simple pythagorean form. In the presence of entanglement, we find that the composite state ‘rotates faster than its parts’, thus unveiling a kinematical origin for the correlation of total variance with entanglement. We analyze a similar definition for the acceleration of a state under rotations, for both pure and mixed states, and probe numerically its relation with a wide array of entanglement related measures.

Divergence and Similarity Characteristics for Two Fuzzy Measures Based on Associated Probabilities

Abstract: The article deals with the definitions of the distance, divergence, and similarity characteristics between two finite fuzzy measures, which are generalizations of the same definitions between two finite probability distributions. As is known, a fuzzy measure can be uniquely represented by the so-called its associated probability class (APC). The idea of generalization is that new definitions of distance, divergence, and similarity between fuzzy measures are reduced to the definitions of distance, divergence, and similarity between the APCs of fuzzy measures. These definitions are based on the concept of distance generator. The proof of the correctness of generalizations is provided. Constructed distance, similarity, and divergence relations can be used in such applied problems as: determining the difference between Dempster-Shafer belief structures; Constructions of collaborative filtering similarity relations; non-additive and interactive parameters of machine learning in phase space metrics definition, object clustering, classification and other tasks. In this work, a new concept is used in the fuzzy measure identification problem for a certain multi-attribute decision-making (MADM) environment. For this, a conditional optimization problem with one objective function representing the distance, divergence or similarity index is formulated. Numerical examples are discussed and a comparative analysis of the obtained results is presented.

Serial Liver Stiffness Measurement and Fibrosis-4 Scores in Metabolic Dysfunction-Associated Steatotic Liver Disease.

In patients with metabolic dysfunction-associated steatotic liver disease (MASLD), there are limited data on how changes in FIB4 and liver stiffness measurement (LSM) correlate in non-biopsy cohorts. Our objective was to evaluate associations between changes in FIB4 and LSM in MASLD patients. We included MASLD patients with serial VCTE from 2015-2022. The primary predictors were change in FIB4 and presence of diabetes, obesity, and high alanine aminotransferase (ALT). The primary outcome, applied only to patients with LSM1 < 8kPa, was incident significant fibrosis (SF) defined as a ≥ 20% increase in LSM2 vs. LSM1 and LSM2 ≥ 8kPa. A secondary outcome was LSM progression with a similar definition but applied to all participants, not only those with LSM1 < 8kPa. Of 285 included patients, 216 had LSM1 < 8kPa and were included in the primary analysis; of these, 34 (16%) had incident SF. Changes in FIB4 correlated with changes in LSM (R = 0.16, p = 0.016). Independent predictors of incident SF included comorbid diabetes mellitus (OR 2.43, 95% CI 1.04-6.56), obesity (OR 3.88, 95% CI 1.63-9.25), and baseline ALT ≥ 30 (OR 8.55, 95% CI 1.10-66.29). A model including ALT, diabetes, and obesity outperformed a model with FIB4 change alone. Among patients with MASLD, changes in FIB4 correlated with changes in LSM but more significant correlates of incident significant fibrosis included diabetes mellitus, obesity, and high baseline ALT.

New options for treatment of chronic pain syndrome

According to the World Health Organization, 12.6 million new cases of cancer were identified in 2008. In 2022, this number reached 18.1 million cases, and it is projected to increase to 26 million in 2040. Chronic pain is defined by the International Association for the Study of Pain as pain that persists or recurs for 3 months. A similar definition is given in the International Classification of Diseases, 11th revision, which for the first time includes chronic pain as an independent category with a unique code MG30. The incidence of pain syndrome in advanced terminal or metastatic stages of cancer is 64 %, during antitumor therapy – 59 %, after successful treatment – 33 %. However, side effects from opioids significantly worsen the quality of life of patients.A new type of peptide drugs can reduce the toxic effects of drug pain therapy.

Glyburide use is associated with a greater likelihood of mortality or rehospitalization after acute coronary syndrome compared to gliclazide use in adults with type 2 diabetes: A cohort study.

To examine the likelihood of mortality or rehospitalization following acute coronary syndrome with glyburide versus gliclazide use in adults with type 2 diabetes undergoing cardiac catheterization. This retrospective cohort study used clinical data linked with administrative health data from Alberta, Canada between April 2008 and March 2021. Three methods were used to define exposure to glyburide and gliclazide in the year before catheterization. Multivariable logistic regression was used to compare the likelihood of a composite outcome of 1-year mortality or rehospitalization with use of glyburide versus use of gliclazide. A total of 11 140 individuals with type 2 diabetes had a cardiac catheterization for acute coronary syndrome. Their mean age was 66 years and 31% were female. In the year before catheterization, 5% used glyburide and 19% used gliclazide. Any glyburide or gliclazide exposure in the year before catheterization was associated with a similar likelihood of all-cause mortality or rehospitalization (adjusted odds ratio [aOR] 1.14, 95% confidence interval [CI] 0.93-1.41; p = 0.20). However, current glyburide exposure (aOR 1.37, 95% CI 1.06-1.79; p = 0.018) and long exposure to glyburide (aOR 1.37, 95% CI 1.03-1.83; p = 0.030) were associated with a higher likelihood of the composite outcome compared to current and long exposure to gliclazide, respectively. Current and long exposure to glyburide was associated with a greater likelihood of mortality or rehospitalization following cardiac catheterization for acute coronary syndrome, when compared to similar gliclazide exposure definitions. This study adds further evidence of the need to avoid using glyburide if a sulphonylurea is required for type 2 diabetes management.

New Results on Rapid Dynamical Pattern Recognition via Deterministic Learning From Sampling Sequences.

Rapid dynamical pattern recognition based on the deterministic learning method (DLM-based RDPR) aims to rapidly recognize the most similar dynamical pattern pair from perspectives of differences in inherent system dynamics. The basic mechanism is to use available recognition errors to reflect the differences in the dynamics of dynamical pattern pairs and then to make a decision based on a minimal recognition error (MRE) principle. This article focuses on providing a rigorous theoretical analysis of the MRE principle in DLM-based RDPR under the sampled-data framework. Specifically, we seek a unified methodology from the similarity definition to the measure implementation and then to derive general sufficient conditions and necessary conditions for the MRE principle. The main idea is to: 1) from the average signal energy aspect, define a time-dependent dynamics-based similarity in dynamical pattern pairs and reestablish the measure of recognition errors generated from the DLM-based RDPR; 2) introduce the energy-based Lyapunov method to establish the interrelation between the dynamical distance and the recognition error; and 3) derive sufficient conditions and necessary conditions from two directions of the interrelation. The proposed conditions distinguish themselves from virtually all of the existing DLM-based RDPR works with only sufficient conditions in the sense that it is shown in a rigorous analysis that under what conditions, the pattern pair recognized based on the MRE principle is indeed the most similar one. Therefore, the proposed work makes the DLM-based RDPR possess good interpretability and provides strong theoretical guidance in engineering applications.

Integrated solar system for hydrogen production using steam reforming of methane

Integrating renewable technologies has emerged as a promising option in pursuing sustainable and efficient energy solutions. The primary source of industrial hydrogen is steam methane reforming (SMR); however, this process is based on fossil fuels with massive carbon byproduct emissions. The solar thermal tower appears to be a suitable renewable source for powering SMR by providing high temperature heat to drive the process reactions. This approach aims to harness the abundance of solar energy for natural gas reforming to produce hydrogen at minimum environmental impact. This research establishes the viability of combining external central receiver concentrated solar power with SMR integrated with thermal energy storage (TES), revealing general insights into the system energy and exergy performance. The analysis of the current system is performed using the thermodynamic and thermochemical approaches to conduct a parametric study. A 543 MW central receiver is first modeled with a high-temperature molten salt as a working fluid. The SMR process model is then developed, considering both reforming and shift reactions, and solved using Engineering Equation Solver (EES). The subsystem models are validated before being integrated into the overall system model. The performance of the SMR reactor is found to affect the overall system performance considerably. The results also show that when increasing the temperature above 760 ° C, no remarkable improvement in the reforming process is observed. In contrast, the higher the temperature in the water gas shift reactor, the lower the system's performance. Moreover, the impact of wind velocity on the overall system is considered due to the large central receiver surface area. The overall system performance in terms of energy, exergy, and effectiveness is evaluated for one day of operating through charging and discharging operations. In charging mode, the overall energy and exergy efficiencies are 46.5% and 57.2%, respectively, while the overall effectiveness is 61.8%; on the discharging operation, the overall energy efficiency and effectiveness have a similar definition with a value of 82.4% and the overall exergy efficiency achieves a value of 78.7%. Additionally, the amount of hydrogen produced at a central receiver of 543 MWth capacity is about 7.3 kg/s at a 2.1 steam-to-carbon ratio. This integration mitigates a minimum of 12 kg/s of CO2 emissions that would be generated due to methane combustion.

Unlocking the Potential of Clustering and Classification Approaches: Navigating Supervised and Unsupervised Chemical Similarity.

The field of toxicology has witnessed substantial advancements in recent years, particularly with the adoption of new approach methodologies (NAMs) to understand and predict chemical toxicity. Class-based methods such as clustering and classification are key to NAMs development and application, aiding the understanding of hazard and risk concerns associated with groups of chemicals without additional laboratory work. Advances in computational chemistry, data generation and availability, and machine learning algorithms represent important opportunities for continued improvement of these techniques to optimize their utility for specific regulatory and research purposes. However, due to their intricacy, deep understanding and careful selection are imperative to align the adequate methods with their intended applications. This commentary aims to deepen the understanding of class-based approaches by elucidating the pivotal role of chemical similarity (structural and biological) in clustering and classification approaches (CCAs). It addresses the dichotomy between general end point-agnostic similarity, often entailing unsupervised analysis, and end point-specific similarity necessitating supervised learning. The goal is to highlight the nuances of these approaches, their applications, and common misuses. Understanding similarity is pivotal in toxicological research involving CCAs. The effectiveness of these approaches depends on the right definition and measure of similarity, which varies based on context and objectives of the study. This choice is influenced by how chemical structures are represented and the respective labels indicating biological activity, if applicable. The distinction between unsupervised clustering and supervised classification methods is vital, requiring the use of end point-agnostic vs. end point-specific similarity definition. Separate use or combination of these methods requires careful consideration to prevent bias and ensure relevance for the goal of the study. Unsupervised methods use end point-agnostic similarity measures to uncover general structural patterns and relationships, aiding hypothesis generation and facilitating exploration of datasets without the need for predefined labels or explicit guidance. Conversely, supervised techniques demand end point-specific similarity to group chemicals into predefined classes or to train classification models, allowing accurate predictions for new chemicals. Misuse can arise when unsupervised methods are applied to end point-specific contexts, like analog selection in read-across, leading to erroneous conclusions. This commentary provides insights into the significance of similarity and its role in supervised classification and unsupervised clustering approaches. https://doi.org/10.1289/EHP14001.

A “set” of ancient bronze bells excavated in Changsha, Hunan Province, China

This article explores the criteria used to ascertain whether or not, and how, ancient Chinese bronze bells might form sets of musical instruments, thus clarifying their original intended use by ancient musicians. The focus is on ten bells unearthed from Changsha city in Hunan province in China, which date to the twelfth century BCE. A range of diverse relationships between these bells provide valuable insights that can be explored. Debate is ongoing among music historians regarding the nature of the bells. Some argue that the ten bells do not constitute a set of musical instruments because their designs and acoustic properties lack sufficient similarity and correlation. Conversely, another group of historians suggests that nine of the ten bells could indeed be seen as a set, but with the tenth bell being an outlier due to its distinct design. The third group of historians contends that the ten bells should be considered a musical set because of their organized sequence of consecutive semi-tones, while the design differences of the bells are less significant and can be overlooked if we focus on their musical functions. In this study, we scrutinize the assumptions made by these music historians, including their definitions of design similarity and the sequence of progressive pitches. Further previously overlooked criteria, such as the geographical proximity of these ten bells and others found in neighboring areas, and the incremental changes in the bell sizes, are also considered. Through the use of these criteria we aim to explore a wide range of relationships between ancient Chinese bells and to reassess what other new evidence the bells may offer to the study of ancient Chinese musical concepts. The concept of the chromatic scale discovered by ancient Chinese musicians was embodied on the casting of bronze bells.

ISSUES OF IMPROVING THE INSTITUTION OF JUDICIAL FINE

The purpose of this article is to consider issues of improving the institution of a judicial fine in the Russian criminal law. The authors consider the similarity in name with other institutions and the direct connection with the provisions of Article 46 of the Criminal Code of the Russian Federation. The authors present different views on the conceptual apparatus of the problem under consideration and its limitation from similar definitions in the field of civil procedure, and also make proposals to change the name for a clearer differentiation. The prospects for reforming the judicial fine in the context of improving criminal legal mechanisms are discussed. Conclusions: It is proposed to establish restrictions on exemption from criminal liability in connection with the imposition of a court fine and the termination of criminal prosecution. These restrictions are proposed to be extended not only by category of crime, but also by the object of the crime, as well as by the nature and degree of public danger. That is, it is proposed to exclude the possibility of applying a judicial fine for certain crimes provided for by individual articles of the special part of the Criminal Code of the Russian Federation.

The effectiveness of aggregation functions used in fuzzy local contrast constructions

In this paper, we explore the concept of local contrast of a fuzzy relation, which can be perceived as a measure for distinguishing the degrees of membership of elements within a defined region of an image. We introduce four distinct methods for constructing fuzzy local contrast: one uses a similarity measure, the second relies on the aggregation of similarity, the third is based on the aggregation of restricted equivalence, and the fourth utilizes the notion of equivalence. We further divide the constructions using similarity measures into two categories based on the two known definitions of similarity: distance-based similarity and aggregation function-based similarity. These construction methods also incorporate fuzzy implications and negations. Aggregation functions, which can be manipulated to enhance the effectiveness of the constructed fuzzy local contrast, play a significant role in most of our proposed constructions. For each construction method, several examples of fuzzy local contrasts are provided. The usefulness of the new fuzzy local contrasts is examined by applying them in image processing for salient region detection.

Sexual Agreement Discussions Among Adolescent Sexual Minority Men in the USA.

Nearly two-thirds of new HIV infections are attributed to primary partners, necessitating a greater understanding of relationship context of HIV transmission among sexual minority men. Sexual agreements, which are the explicit decisions couples make about sexual behaviors allowed inside and outside of their relationship, have been primarily studied among adult sexual minority men. Little work has sought to understand how adolescent sexual minority men utilize and navigate sexual agreement conversations. In this qualitative study, we explored adolescent sexual minority men's motivations for having these conversations, how they define different types of agreements (e.g., monogamous, non-monogamous), and the topics most commonly discussed in their conversations. We conducted thematic analysis of in-depth interviews with 30 partnered, HIV-negative, adolescent sexual minority men ages 15-19years. Participants reported similar reasons, definitions, and desires for creating sexual agreements as those reported in the adult literature. Novel to this population was the influence of stigma and heterosexism on the participants' choice of sexual agreement type. Like adult sexual minority men, participants used sexual agreement conversations to respond to life events; however, the adolescents in our sample, when talking with their partners, led with the context of developmentally specific events such as leaving for college or attending a school dance. Those with more relationship experience often described having intentional, explicit sexual agreement conversations. Study findings suggest that content focused on sexual agreements is important for HIV prevention interventions designed with adolescent sexual minority men, especially young men who have less relationship experiences.

Аристотель о запахе и обонянии

This article is devoted to the sense of smell in Aristotle’s psychology. Aristotle defines all senses by their proper objects. In the case of sense of smell, this is difficult to do, because the human sense of smell is poorly developed. In addition, the odor itself is problematic, ac­cording to Aristotle, it appears only under certain conditions. The purpose of this work was to consider the main aspects of Aristotle’s theory of the sense of smell. In this article, spe­cial attention will be paid to the following topics. Firstly, I considered the nature of odor: 1) why Aristotle defines odors and flavors as “almost the same affection”; 2) why odor should be considered as ἔγχυμον ξηρόν, and not as ἔγχυμον ὑγρόν; 3) what is the property of water and air, which plays the crucial role in the appearance of odors. Secondly, the ques­tion of the structure of the olfactory organ. Thirdly, the question of types of odors. And fourthly, the question of the place of the sense of smell among the other senses. It is shown that: 1) although Aristotle gives similar definitions of odors and flavors, he does not re­duce them to one another; 2) the medium plays the crucial role in distinguishing them; 3) the analogy between kinds of flavors and kinds of odors is not based on mathematical proportion of components; 4) the two types of odors named by Aristotle in De Sensu cannot have the same physical nature; 5) many difficulties concerning the sense of smell are con­nected with the specific role that it plays among other senses.

Using Response Times in Answer Similarity Analysis

Recent decades have seen a tremendous growth in the development of collusion detection methods, many of which rest on the assumption that examinees who engage in collusion will display unusually similar scores/responses. In this article, we expand the definition of answer similarity to include not only the item scores/responses but also the item response times (RTs). Using detailed simulations and an experimental data set, we show that (a) both the new and existing similarity statistics are able to control the Type I error rate in most of the studied conditions and (b) the new statistics are much more powerful, on average, than the existing statistics at detecting several types of simulated collusion.