Examining the Relationship Between Weapon Type and Relationship Type in American Homicides: A Bayesian Approach

2020 ◽  
Author(s):  
Joshua J Reynolds ◽  
Paul - Christian Bürkner
Keyword(s):  
Bayesian Approach ◽  
Past Research ◽  
Small Sample ◽  
Limited Data ◽  
Relationship Type ◽  
Final Model ◽  
Categorical Regression ◽  
Small Sample Sizes ◽  
The Relationship ◽  
Data Analytic

Past research indicates that weapon type used in a homicide predicts the victim-perpetrator relationship. Limitations include small sample sizes, inconsistent findings, and limited data analytic techniques. To address these limitations, we examined 363,927 homicides and used Bayesian multilevel categorical regression. In addition to analyzing weapon type (final model consisted of 16 weapon categories), we examined the victims’ sex, age, and race as covariates and modeled the data across states and counties. Results indicate that weapon type is highly informative, however, the age of the victim and sex of the victim interact with weapon type in important ways.

Examining the Relationship Between Weapon Type and Relationship Type in American Homicides: A Bayesian Approach

2020 ◽  
pp. 108876792097619
Author(s):  
Joshua J. Reynolds ◽  
Paul C. Bürkner
Keyword(s):  
Bayesian Approach ◽  
Past Research ◽  
Relationship Type ◽  
Final Model ◽  
Categorical Regression ◽  
The Common ◽  
The Relationship ◽  
Data Analytic

The weapon type used in a homicide predicts the victim-perpetrator relationship. However, there are some limitations in this past research including the common data analytic strategies. Our purpose was to build a model of weapon type, predicting relationship type, and to address previous limitations. We examined 363,927 homicides and used Bayesian multilevel categorical regression. In addition to analyzing weapon type (final model consisted of 16 weapon categories), we examined the victims’ sex, age, and race as covariates and modeled the data across states and counties. Results indicate that weapon type is highly informative, however, the age of the victim and sex of the victim interact in important ways.

scholarly journals A Connectome-Wide Functional Signature of Trait Anger

2021 ◽  
pp. 216770262110302
Author(s):  
M. Justin Kim ◽  
Maxwell L. Elliott ◽  
Annchen R. Knodt ◽  
Ahmad R. Hariri
Keyword(s):  
Functional Connectivity ◽  
Visual Information ◽  
Past Research ◽  
Brain Regions ◽  
Small Sample ◽  
Trait Anger ◽  
Frontal Pole ◽  
Brain Correlates ◽  
Small Sample Sizes ◽  
The Right

Past research on the brain correlates of trait anger has been limited by small sample sizes, a focus on relatively few regions of interest, and poor test–retest reliability of functional brain measures. To address these limitations, we conducted a data-driven analysis of variability in connectome-wide functional connectivity in a sample of 1,048 young adult volunteers. Multidimensional matrix regression analysis showed that self-reported trait anger maps onto variability in the whole-brain functional connectivity patterns of three brain regions that serve action-related functions: bilateral supplementary motor areas and the right lateral frontal pole. We then demonstrate that trait anger modulates the functional connectivity of these regions with canonical brain networks supporting somatomotor, affective, self-referential, and visual information processes. Our findings offer novel neuroimaging evidence for interpreting trait anger as a greater propensity to provoked action, which supports ongoing efforts to understand its utility as a potential transdiagnostic marker for disordered states characterized by aggressive behavior.

scholarly journals The relationship between dose and serotonin transporter occupancy of antidepressants—a systematic review

2021 ◽  
Author(s):  
Anders Sørensen ◽  
Henricus G. Ruhé ◽  
Klaus Munkholm
Keyword(s):  
Serotonin Transporter ◽  
Antidepressant Treatment ◽  
Imaging Techniques ◽  
Small Sample ◽  
Short Treatment ◽  
Predicted Values ◽  
Small Sample Sizes ◽  
The Relationship ◽  
Short Treatment Duration

AbstractBrain imaging techniques enable the visualization of serotonin transporter (SERT) occupancy as a measure of the proportion of SERT blocked by an antidepressant at a given dose. We aimed to systematically review the evidence on the relationship between antidepressant dose and SERT occupancy. We searched PubMed and Embase (last search 20 May 2021) for human in vivo, within-subject PET, or SPECT studies measuring SERT occupancy at any dose of any antidepressant with highly selective radioligands ([11C]-DASB, [123I]-ADAM, and [11C]-MADAM). We summarized and visualized the dose-occupancy relationship for antidepressants across studies, overlaying the plots with a curve based on predicted values of a standard 2-parameter Michaelis–Menten model fitted using the observed data. We included seventeen studies of 10 different SSRIs, SNRIs, and serotonin modulators comprising a total of 294 participants, involving 309 unique occupancy measures. Overall, following the Michaelis–Menten equation, SERT occupancy increased with a higher dose in a hyperbolic relationship, with occupancy increasing rapidly at lower doses and reaching a plateau at approximately 80% at the usual minimum recommended dose. All the studies were small, only a few investigated the same antidepressant, dose, and brain region, and few reported information on factors that may influence SERT occupancy. The hyperbolic dose-occupancy relationship may provide mechanistic insight of relevance to the limited clinical benefit of dose-escalation in antidepressant treatment and the potential emergence of withdrawal symptoms. The evidence is limited by non-transparent reporting, lack of standardized methods, small sample sizes, and short treatment duration. Future studies should standardize the imaging and reporting procedures, measure occupancy at lower antidepressant doses, and investigate the moderators of the dose-occupancy relationship.

scholarly journals Resting heart rate and psychopathy: Findings from the Add Health Survey

2017 ◽  
Author(s):  
Nicholas Kavish ◽  
Q. John Fu ◽  
Michael G. Vaughn ◽  
Zhengmin Qian ◽  
Brian B. Boutwell
Keyword(s):  
Heart Rate ◽  
Small Body ◽  
Psychopathic Traits ◽  
Small Sample ◽  
Future Research ◽  
Alternative Measure ◽  
Resting Heart Rate ◽  
Nationally Representative ◽  
Small Sample Sizes ◽  
The Relationship

AbstractDespite the prior linkages of low resting heart rate to antisocial behavior broadly defined, less work has been done examining possible associations between heart rate to psychopathic traits. The small body of research on the topic that has been conducted so far seems to suggest an inverse relationship between the two constructs. A smaller number of studies have found the opposite result, however, and some of the previous studies have been limited by small sample sizes and unrepresentative samples. The current study attempts to help clarify the relationship between resting heart rate and psychopathic traits in a large, nationally representative sample (analytical N ranged from 14,173-14,220) using an alternative measure of psychopathic traits that is less focused on antisocial processes, and rooted in personality traits. No significant relationship between heart rate and psychopathic traits, or heart rate and a measure of cold heartedness, was found after controlling for age, sex, and race. Implications of the findings, study limitations, and directions for future research are discussed.

The Relationship Between Sample Sizes and Effect Sizes in Systematic Reviews in Education

2009 ◽  
Vol 31 (4) ◽  
pp. 500-506 ◽  
Author(s):  
Robert Slavin ◽  
Dewi Smith
Keyword(s):  
Sample Size ◽  
Effect Size ◽  
Secondary Mathematics ◽  
Significant Negative Correlation ◽  
Small Sample ◽  
Effect Sizes ◽  
Sample Sizes ◽  
Large Samples ◽  
Small Sample Sizes ◽  
The Relationship

Research in fields other than education has found that studies with small sample sizes tend to have larger effect sizes than those with large samples. This article examines the relationship between sample size and effect size in education. It analyzes data from 185 studies of elementary and secondary mathematics programs that met the standards of the Best Evidence Encyclopedia. As predicted, there was a significant negative correlation between sample size and effect size. The differences in effect sizes between small and large experiments were much greater than those between randomized and matched experiments. Explanations for the effects of sample size on effect size are discussed.

scholarly journals Sports genetics moving forward: lessons learned from medical research

2016 ◽  
Vol 48 (3) ◽  
pp. 175-182 ◽  
Author(s):  
C. Mikael Mattsson ◽  
Matthew T. Wheeler ◽  
Daryl Waggott ◽  
Colleen Caleshu ◽  
Euan A. Ashley
Keyword(s):  
Medical Research ◽  
Rare Variants ◽  
Small Sample ◽  
Lessons Learned ◽  
Limited Data ◽  
Sample Sizes ◽  
Scientific Rigor ◽  
Depth Of Knowledge ◽  
Sports Science ◽  
Small Sample Sizes

Sports genetics can take advantage of lessons learned from human disease genetics. By righting past mistakes and increasing scientific rigor, we can magnify the breadth and depth of knowledge in the field. We present an outline of challenges facing sports genetics in the light of experiences from medical research. Sports performance is complex, resulting from a combination of a wide variety of different traits and attributes. Improving sports genetics will foremost require analyses based on detailed phenotyping. To find widely valid, reproducible common variants associated with athletic phenotypes, study sample sizes must be dramatically increased. One paradox is that in order to confirm relevance, replications in specific populations must be undertaken. Family studies of athletes may facilitate the discovery of rare variants with large effects on athletic phenotypes. The complexity of the human genome, combined with the complexity of athletic phenotypes, will require additional metadata and biological validation to identify a comprehensive set of genes involved. Analysis of personal genetic and multiomic profiles contribute to our conceptualization of precision medicine; the same will be the case in precision sports science. In the refinement of sports genetics it is essential to evaluate similarities and differences between sexes and among ethnicities. Sports genetics to date have been hampered by small sample sizes and biased methodology, which can lead to erroneous associations and overestimation of effect sizes. Consequently, currently available genetic tests based on these inherently limited data cannot predict athletic performance with any accuracy.

scholarly journals Bilateral volume reduction in posterior hippocampus in psychosis of epilepsy

2019 ◽  
Vol 90 (6) ◽  
pp. 688-694 ◽  
Author(s):  
James Allebone ◽  
Richard Kanaan ◽  
Jerome Maller ◽  
Terry O'Brien ◽  
Saul Alator Mullen ◽  
...  
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Past Research ◽  
Hippocampal Volume ◽  
Small Sample ◽  
The Body ◽  
Similar Degree ◽  
Hippocampal Atrophy ◽  
Small Sample Sizes ◽  
Patients With Epilepsy

ObjectivePsychosis of epilepsy (POE) occurs more frequently in temporal lobe epilepsy, raising the question as to whether abnormalities of the hippocampus are aetiologically important. Despite decades of investigation, it is unclear whether hippocampal volume is reduced in POE, perhaps due to small sample sizes and methodological limitations of past research.MethodsIn this study, we examined the volume of the total hippocampus, and the hippocampal head, body and tail, in a large cohort of patients with POE and patients with epilepsy without psychosis (EC). One hundred adults participated: 50 with POE and 50 EC. Total and subregional hippocampal volumes were manually traced and compared between (1) POE and EC; (2) POE with temporal lobe epilepsy, extratemporal lobe epilepsy and generalised epilepsy; and (3) patients with POE with postictal psychosis (PIP) and interictal psychosis (IP).ResultsCompared with EC the POE group had smaller total left hippocampus volume (13.5% decrease, p<0.001), and smaller left hippocampal body (13.3% decrease, p=0.002), and left (41.5% decrease, p<0.001) and right (36.4% decrease, p<0.001) hippocampal tail volumes. Hippocampal head volumes did not differ between groups.ConclusionPosterior hippocampal volumes are bilaterally reduced in POE. Volume loss was observed on a posteroanterior gradient, with severe decreases in the tail and moderate volume decreases in the body, with no difference in the hippocampal head. Posterior hippocampal atrophy is evident to a similar degree in PIP and IP. Our findings converge with those reported for the paradigmatic psychotic disorder, schizophrenia, and suggest that posterior hippocampal atrophy may serve as a biomarker of the risk for psychosis, including in patients with epilepsy.

scholarly journals Rasch Versus Classical Equating in the Context of Small Sample Sizes

2019 ◽  
Vol 80 (3) ◽  
pp. 499-521
Author(s):  
Ben Babcock ◽  
Kari J. Hodge
Keyword(s):  
Item Difficulty ◽  
Real Data ◽  
Past Research ◽  
Small Sample ◽  
Small Samples ◽  
Sample Sizes ◽  
Certification Exam ◽  
Small Sample Sizes ◽  
The Rasch Model ◽  
Better Than

Equating and scaling in the context of small sample exams, such as credentialing exams for highly specialized professions, has received increased attention in recent research. Investigators have proposed a variety of both classical and Rasch-based approaches to the problem. This study attempts to extend past research by (1) directly comparing classical and Rasch techniques of equating exam scores when sample sizes are small ( N≤ 100 per exam form) and (2) attempting to pool multiple forms’ worth of data to improve estimation in the Rasch framework. We simulated multiple years of a small-sample exam program by resampling from a larger certification exam program’s real data. Results showed that combining multiple administrations’ worth of data via the Rasch model can lead to more accurate equating compared to classical methods designed to work well in small samples. WINSTEPS-based Rasch methods that used multiple exam forms’ data worked better than Bayesian Markov Chain Monte Carlo methods, as the prior distribution used to estimate the item difficulty parameters biased predicted scores when there were difficulty differences between exam forms.

scholarly journals What’s in a Coefficient? The “Not so Simple” Interpretation of R2, for Relatively Small Sample Sizes

2019 ◽  
Vol 7 (12) ◽  
pp. 27
Author(s):  
Nizar Zaarour ◽  
Emanuel Melachrinoudis
Keyword(s):  
Standard Deviation ◽  
Linear Regression ◽  
Small Sample ◽  
Coefficient Of Determination ◽  
Simple Linear Regression ◽  
Sample Sizes ◽  
Simple Interpretation ◽  
Small Sample Sizes ◽  
Level Of Significance ◽  
The Relationship

There are several misconceptions when interpreting the values of the coefficient of determination, R2, in simple linear regression. R2 is heavily dependent on sample size n and the type of data being analyzed but becomes insignificant when working with very large sample sizes. In this paper, we comment on these observations and develop a relationship between R2, n, and the level of significance α, for relatively small sample sizes. In addition, this paper provides a simplified version of the relationship between R2 and n, by comparing the standard deviation of the dependent variable, Sy, to the standard error of the estimate, Se. This relationship will serve as a safe lower bound to the values of R2. Computational experiments are performed to confirm the results from both models. Even though the focus of the paper is on simple linear regression, we present the groundwork for expanding our two models to the multiple regression case.

scholarly journals Limits to Genomic Divergence Under Sexually Antagonistic Selection

2019 ◽  
Author(s):  
Katja R. Kasimatis ◽  
Peter L. Ralph ◽  
Patrick C. Phillips
Keyword(s):  
Genetic Model ◽  
Empirical Studies ◽  
Genetic Load ◽  
Small Sample ◽  
Sampling Variance ◽  
Antagonistic Selection ◽  
Genome Wide ◽  
Sexually Antagonistic Selection ◽  
Small Sample Sizes ◽  
The Relationship

AbstractSince the autosomal genome is shared between the sexes, sex-specific fitness optima present an evolutionary challenge. While sexually antagonistic selection might favor different alleles within females and males, segregation randomly reassorts alleles at autosomal loci between sexes each generation. This process of homogenization during transmission thus prevents between-sex allelic divergence generated by sexually antagonistic selection from accumulating across multiple generations. However, recent empirical studies have reported high male-female FST statistics. Here, we use a population genetic model to evaluate whether these observations could plausibly be produced by sexually antagonistic selection. To do this, we use both a single-locus model with nonrandom mate choice, and individual-based simulations to study the relationship between strength of selection, degree of between-sex divergence, and the associated genetic load. We show that selection must be exceptionally strong to create measurable divergence between the sexes and that the decrease in population fitness due to this process is correspondingly high. Individual-based simulations with selection genome-wide recapitulate these patterns and indicate that small sample sizes and sampling variance can easily generate substantial male-female divergence. We therefore conclude that caution should be taken when interpreting autosomal allelic differentiation between the sexes.

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