Starting the Conversation Around the Ethical Use of Artificial Intelligence in Applied Behavior Analysis

Artificial intelligence (AI) is increasingly a part of our everyday lives. Though much AI work in healthcare has been outside of applied behavior analysis (ABA), researchers within ABA have begun to demonstrate many different ways that AI might improve the delivery of ABA services. Though AI offers many exciting advances, absent from the behavior analytic literature thus far is conversation around ethical considerations when developing, building, and deploying AI technologies. Further, though AI is already in the process of coming to ABA, it is unknown the extent to which behavior analytic practitioners are familiar (and comfortable) with the use of AI in ABA. The purpose of this article is twofold. First, to describe how existing ethical publications (e.g., BACB Code of Ethics) do and do not speak to the unique ethical concerns with deploying AI in everyday, ABA service delivery settings. Second, to raise questions for consideration that might inform future ethical guidelines when developing and using AI in ABA service delivery. In total, we hope this article sparks proactive dialog around the ethical use of AI in ABA before the field is required to have a reactionary conversation.

The Promises and Possibilities of Artificial Intelligence in the Delivery of Behavior Analytic Services

Artificial intelligence (AI) has begun to affect nearly every aspect of our daily lives and nearly every industry and profession. Many readers of this journal likely work in one or more areas of behavioral health. For readers who work in behavioral health and who are interested in AI, the purpose of this article is to highlight the pervasiveness of AI research being conducted around many facets of behavioral health service delivery. To do this, we first provide a brief overview of some of the areas within AI and the types of problems each area of AI attempts to solve. We then outline the prototypical client journey in behavioral healthcare beginning with diagnosis/assessment and ending with intervention withdrawal or ongoing monitoring. Next, for each stage in the client journey, we highlight several areas that parallel existing behavior analytic practice where researchers have begun to use AI, often to improve the efficiency of service delivery or to learn new things that improve the effectiveness of behavioral health services. Finally, for those whose appetite has been whet for getting involved with AI, we close by describing three roles they might consider trying out and that parallel the three main domains of behavior analysis. These three roles are an AI tool designer (akin to EAB), AI tool implementer (akin to ABA), or AI tool supporter (akin to practice).

Efficacy of Edible and Leisure Reinforcers with Domestic Dogs

Preference assessments are often used to identify stimuli that function as potential reinforcers for training or intervention purposes. Specifically, various preference assessment formats have been used to identify preferred stimuli for humans, cockroaches, cotton-top tamarins, tortoises, and wolves, to name a few. However, to date, no study has evaluated the differential efficacy between food and leisure stimuli within domestic dogs. The current study aimed to compare the reinforcing value and efficacy between food and leisure stimuli for domestic dogs by comparing rates of behavior when receiving access to either their top-preferred food or leisure items. Overall results suggest (1) domestic dogs prefer food over leisure items, and (2) food is more likely to function as a reinforcer than leisure items for domestic dog's behavior. These results suggest that dog owners and trainers should consider using food reinforcers over leisure items as reinforcers when attempting to train dogs.

Effects of economic context and reward amount on delay and probability discounting

Steep delay and shallow probability discounting are associated with myriad problem behaviors; thus, it is important to understand factors that influence the degree of discounting. The present study evaluated the effects of economic context and reward amount on delay and probability discounting. Two hundred thirteen undergraduate psychology students completed four delay- or probability-discounting tasks. Participants were exposed to hypothetical narratives involving four bank amounts ($750, $12,000, $125,000, and $2,000,000). The delayed/probabilistic amount was $3,000 for the two smaller bank amounts and $500,000 for the two larger bank amounts. The discounting tasks included five delays to, or probabilities of, receipt of the larger amount. The area under the empirical discounting function was calculated for each participant. Participants discounted delayed and uncertain outcomes more when the bank amount was smaller than the outcome (i.e., the economic context was low). Participants discounted the delayed larger amounts less than delayed smaller amounts, even when the relative economic context was the same. In contrast, probability discounting did not differ across magnitudes, which suggests that economic context may attenuate the magnitude effect in probability discounting. The results further highlight the importance of considering the economic context in delay and probability discounting.

Identifying Trends in the Open-Access Behavior Analytic Literature via Computational Analyses (I): Simple Descriptions of Text

Published research in scientific journals are critical resources for researchers as primary sources about: what is important in the field, the direction the field is headed, how the field relates to other sciences, and as a historical record for each of these. In this exploratory study, we analyzed the articles of five behavior analytic journals to identify trends in these areas. To do this, we downloaded all available articles (N = 10,405) since the inception of five behavior analytic journals and one control journal. We then used computational techniques to turn the collection of raw text into a structured dataset for descriptive, exploratory analyses. We found consistent differences in the length and variability of published research across behavior analytic journals compared to a control journal. We also found increasing article lengths over time which, combined with the previous finding, may highlight changing editorial contingencies that influence the writing behavior of researchers. Further, we found evidence suggesting distinct (though still connected) verbal communities between the experimental analysis of behavior and applied behavior analysis. Lastly, keyword trends suggest that increased focus on "functional analyses," "problem behavior," and "autism spectrum disorder" currently dominates the research being published in these journals similar to the practitioner arm of behavior analysis. Researchers interested in studying published behavior analytic textual stimuli will find the corresponding open dataset useful. And, for those interested in computational analyses of these data, this first pass at simple descriptions provides a launching point for much fruitful future research.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40616-022-00179-4.

High-precision measurement of the W boson mass with the CDF II detector

The mass of the W boson, a mediator of the weak force between elementary particles, is tightly constrained by the symmetries of the standard model of particle physics. The Higgs boson was the last missing component of the model. After observation of the Higgs boson, a measurement of the W boson mass provides a stringent test of the model. We measure the W boson mass, M_W, using data corresponding to 8.8 inverse femtobarns of integrated luminosity collected in proton-antiproton collisions at a 1.96 tera-electron volt center-of-mass energy with the CDF II detector at the Fermilab Tevatron collider. A sample of approximately 4 million W boson candidates is used to obtain [Formula: see text], the precision of which exceeds that of all previous measurements combined (stat, statistical uncertainty; syst, systematic uncertainty; MeV, mega-electron volts; c, speed of light in a vacuum). This measurement is in significant tension with the standard model expectation.

Verbal behavior related to drug reinforcement in polysubstance cannabis users: Comparison across drugs

Verbal reports of drug effects are often used in behavioral pharmacology. Two reports related to reinforcement are drug use (Harford, 1978; Liu et al., 2018) frequency and drug preference. Anecdotally, some individuals may specify a favorite/preferred drug (e.g., psilocybin) despite using another drug more frequently (e.g., tobacco). Research comparing these two measures has led to contradictory findings and included ratings from participants who may not have experience with the rated drugs. No comparisons have been made between use frequency and preference across multiple drugs in polysubstance users. To compare use frequency and preference for drug classes, and examine relations across drug classes, individuals reporting polysubstance use (N = 428) provided frequency and preference ratings for nine drug classes. Mean ratings showed smoked tobacco, alcohol, and cannabis were the most frequently used and most preferred drugs. Mean ratings showed 3,4-Methylenedioxymethamphetamine (MDMA) and classic hallucinogens were the least frequently used and least preferred drugs. However, more divergence between use frequency and preference was observed when these metrics were examined among individuals. Correlation coefficients between use frequency and preference were lower than previously published literature. The majority of polydrug comparisons were nonsignificant, and correlations between different drug classes differed depending on whether use frequency or preference was examined. Verbal reports about use frequency are likely not strongly predictive of verbal reports about the same drug preference. Clinicians and researchers should recognize that different verbal reports related to drug reinforcement might be proxies for distinct aspects of reinforcement and should consider these implications for assessment and research findings. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

What's the Big IDEA? A Preliminary Analysis of Behavior Analysts' Self-Reported Training in and Knowledge of Federal Special Education Law

Many behavior analysts currently work in school settings or with individuals who may qualify for educational services through federal special education law. However, it remains unclear what training, if any, behavior analysts receive in this law. Behavior analysts have an ethical responsibility to practice within their scope of competency and in compliance with legal regulations. Thus, it is important to determine whether behavior analysts practicing in the United States are adequately prepared and familiar with federal special education law. The current study consisted of a survey wherein respondents answered questions pertaining to the relevance of federal special education law, their familiarity with core terminology, and the alignment between the law and the Professional and Ethical Compliance Code for Behavior Analysts (Behavior Analyst Certification Board, 2016). Respondents' self-report indicates that behavior analysts hold conflicting views on how federal special education law aligns with and influences their role as service providers. As such, practitioners and agencies alike may benefit from explicit clarification of the responsibility Board Certified Behavior Analysts have to seek training in and adhere to federal special education law.

Sexual discounting: A systematic review of discounting processes and sexual behavior

Behavioral processes underlying sexual behavior are important for understanding normal human functioning and risk behavior leading to sexually transmitted infections (STIs). This systematic review examines delay and probability discounting in human sexual behavior through synthesis of 50 peer-reviewed, original research articles. Sixteen studies focusing exclusively on monetary delay discounting found small effect size positive correlations with sexual risk behaviors. Eleven studies examined delay or probability discounting of sexual behavior itself using tasks that varied duration, frequency, or quality of sex to determine value. Results show delay and uncertainty of sex causes systematic decreases in value. These studies also show consistent medium effect size relationships between sexual discounting measures and sexual health and substance use, supporting utility above and beyond monetary discounting. Twenty-three studies have modeled clinically relevant decision-making, examining effects of delay until condom availability and STI contraction probability on condom use. Observational and experimental designs found condom-use discounting is elevated in high-risk substance use populations, is sensitive to context (e.g., partner desirability), and is more robustly related to sexual risk compared with monetary discounting or condom use decisions when no delay/uncertainty was involved. Administering cocaine, alcohol, and, for some participants, methamphetamine increased condom-use discounting with minimal effect on monetary discounting or condom use when no delay/uncertainty was involved. Reviewed studies robustly support that sexual behavior is highly dependent on delay and probability discounting, and that these processes strongly contribute to sexual risk. Future research should exploit these systematic relationships to design behavioral and pharmacological approaches to decrease sexual risk behavior. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Sexual Arousal Discounting: Devaluing Condom-Protected Sex as a Function of Reduced Arousal

Sexual discounting is a growing area of research aimed at identifying factors that reduce people's reported willingness to have safe sex. One commonly reported reason for condom non-use is that a condom reduces sexual arousal. However, researchers have yet to isolate the specific role of sexual arousal using a sexual discounting framework. We extended past research by measuring how sexual arousal reduced people's willingness to have condom-protected sex ("sexual arousal discounting": SAD). College students (n = 379; 67.5% females) selected partners they most wanted and least wanted to have sex with and were randomized to one of two groups. In one group, participants rated their willingness to have sex with a condom if their own arousal decreased (from 100 to 10%) from condom use. The other group completed the same task except their partner's arousal decreased from condom use instead of their own. We observed a three-way interaction between arousal levels, most versus least desirable partners, and self versus partner groups. Participants' willingness to have condom-protected sex systematically reduced as a function of sexual arousal. This was observed more with the most (vs. least) desirable partner and in the self-arousal (vs. partner-arousal) group but only when the partner was their least desirable. Men (vs. women) displayed more arousal discounting but only with the most desirable partner. Finally, higher arousal discounting was associated with lower safe-sex self-efficacy and higher reported frequency of unprotected sex in the past 3 months. This study demonstrates how reduced sexual arousal from condom use can be measured as a factor influencing sexual risk-taking.

Predicting changes in substance use following psychedelic experiences: natural language processing of psychedelic session narratives

Background: Experiences with psychedelic drugs, such as psilocybin or lysergic acid diethylamide (LSD), are sometimes followed by changes in patterns of tobacco, opioid, and alcohol consumption. But, the specific characteristics of psychedelic experiences that lead to changes in drug consumption are unknown.Objective: Determine whether quantitative descriptions of psychedelic experiences derived using Natural Language Processing (NLP) would allow us to predict who would quit or reduce using drugs following a psychedelic experience.Methods: We recruited 1141 individuals (247 female, 894 male) from online social media platforms who reported quitting or reducing using alcohol, cannabis, opioids, or stimulants following a psychedelic experience to provide a verbal narrative of the psychedelic experience they attributed as leading to their reduction in drug use. We used NLP to derive topic models that quantitatively described each participant's psychedelic experience narrative. We then used the vector descriptions of each participant's psychedelic experience narrative as input into three different supervised machine learning algorithms to predict long-term drug reduction outcomes.Results: We found that the topic models derived through NLP led to quantitative descriptions of participant narratives that differed across participants when grouped by the drug class quit as well as the long-term quit/reduction outcomes. Additionally, all three machine learning algorithms led to similar prediction accuracy (~65%, CI = ±0.21%) for long-term quit/reduction outcomes.Conclusions: Using machine learning to analyze written reports of psychedelic experiences may allow for accurate prediction of quit outcomes and what drug is quit or reduced within psychedelic therapy.

A Guide to Establishing Ethics Committees in Behavioral Health Settings

Ethical statements typically involve rules. All rules can vary in accuracy and specificity depending on the context to which they are applied. Codes of ethics often involve ethical rules that are written generally to cover the wide-ranging set of possible situations that any one member of the profession may encounter. But, despite being written generally, codes of ethics are applied to specific situations that professional members encounter. The application of general rules to specific contexts can sometimes be challenging and complex. Health care organizations have several options to help their employees behave ethically. One approach is to appoint a single ethics coordinator. In contrast, the dominant approach in most health care organizations is to develop an organizational ethics committee (Moon Pediatrics, 143(5), e20190659, 2019). Despite the popularity of the ethics committee in other professions, the extent to which organizations that provide applied behavior analysis services have established and operate ethics committees is unknown. Ethics coordinator roles and ethics committees both have benefits and drawbacks. This article reviews the benefits and drawbacks of appointing an ethics coordinator and establishing an ethics committee. And, for interested organizations, this article outlines the steps and considerations that organizations can use to guide the creation of an ethics committee.

Delay and probability discounting in cocaine use disorder: Comprehensive examination of money, cocaine, and health outcomes using gains and losses at multiple magnitudes

Understanding factors associated with cocaine use disorder is important given its public health impact. One factor is delay discounting (devaluation of future consequences). Cocaine users have shown greater delay discounting of money rewards than non-cocaine users. But underexamined are factors known to affect discounting, such as the sign (reward vs. loss), magnitude (e.g., $10 vs. $1,000), and commodity (e.g., money vs. health) of the consequence. Also underexamined is probability discounting (devaluation of uncertain consequences). We conducted a comprehensive group-comparison study of discounting processes by comparing sign, magnitude, and commodity effects between demographically matched cocaine users (n = 23) and never users (n = 24) for delay discounting and sign and magnitude effects for probability discounting. Participants completed delay and probability discounting tasks spanning rewards and losses; money, cocaine, and health outcomes; and magnitudes of $10, $100, and $1,000. Four primary findings emerged when controlling for other drug use. First, cocaine users pervasively discounted delayed consequences more than never users regardless of sign, magnitude, or commodity, with the possible exception of delay discounting of $1,000 health equivalences. Second, both groups discounted delayed rewards more than losses, with a similar trend for probability discounting. Third, magnitude effects in cocaine users for delayed and probabilistic outcomes were similar to those previously observed in never users and other-drug users. Fourth, cocaine users discounted cocaine-related outcomes more than money and health, with variable results comparing money and health. These data suggest that the behavioral processes of delay and probability discounting are qualitatively similar for cocaine users and never users. However, quantitatively, cocaine users generally showed greater delay discounting and similar probability discounting compared with never users. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

A Proposed Process for Risk Mitigation During the COVID-19 Pandemic

Recent executive orders have led some applied behavior analysis (ABA) providers to interpret themselves as "essential personnel" during the COVID-19 pandemic. In this article, we argue against a blanket interpretation that being labeled "essential personnel" means that all in-person ABA services for all clients should continue during the COVID-19 pandemic. We believe this argument holds even if ABA providers are not in a jurisdiction currently under an active shelter-at-home or related order. First, we provide a brief description of risks associated with continued in-person ABA service delivery, as well as risks associated with the temporary suspension of services or the transition to remote ABA service delivery. For many clients, continued in-person service delivery carries a significant risk of severe harm to the client, family and caregivers, staff, and a currently overburdened health care system. In these situations, ABA providers should temporarily suspend services or transition to telehealth or other forms of remote service delivery until information from federal, state, and local health care experts deems in-person contact safe. In rare cases, temporary suspension of services or a transition to remote service delivery may place the client or others at risk of significant harm. In these situations, in-person services should likely continue, and ongoing assessment and risk mitigation are essential.

Comparison of multiplicative and additive hyperbolic and hyperboloid discounting models in delayed lotteries involving gains and losses

Many day-to-day decisions may involve risky outcomes that occur at some delay after a decision has been made. We refer to such scenarios as delayed lotteries. Despite human choice often involves delayed lotteries, past research has primarily focused on decisions with delayed or risky outcomes. Comparatively, less research has explored how delay and probability interact to influence decisions. Within research on delayed lotteries, rigorous comparisons of models that describe choice from the discounting framework have not been conducted. We performed two experiments to determine how gain or loss outcomes are devalued when delayed and risky. Experiment 1 used delay and probability ranges similar to past research on delayed lotteries. Experiment 2 used individually calibrated delay and probability ranges. Ten discounting models were fit to the data using a genetic algorithm. Candidate models were derived from past research on discounting delayed or probabilistic outcomes. We found that participants' behavior was best described primarily by a three-parameter multiplicative model. Measures based on information criteria pointed to a solution in which only delay and probability were psychophysically scaled. Absolute measures based on residuals pointed to a solution in which amount, delay, and probability are simultaneously scaled. Our research suggests that separate scaling parameters for different discounting factors may not be necessary with delayed lotteries.

Kratom (Mitragyna speciosa): User demographics, use patterns, and implications for the opioid epidemic

BACKGROUND

Kratom, a Southeast Asian plant with opioid-receptor mediated effects, has emerged as a potential substance of abuse, with limited data on its use and effects. This study characterized kratom user demographics, use patterns, and perceived drug effects.

METHODS

A cross-sectional, anonymous online survey was conducted between January and December 2017.

RESULTS

2,798 kratom users - mean age 40 (SD = 12); predominantly White (90 %), female (61 %), and located in the US (97 %) - completed the survey. Kratom was primarily taken orally in doses of 1-3 g (49 %), with daily use (59 %) being most common. Kratom was used for pain (91 %), anxiety (67 %), and depression (65 %), with high ratings of effectiveness. 1,144 (41 %) used kratom to stop or reduce prescription or illicit opioid use, citing decreased opioid withdrawal and craving related to kratom use, with 411 reporting >1-year continuous abstinence from opioids attributed to kratom use. Roughly one-third of respondents reported adverse effects of kratom, largely rated as mild in severity and lasting ≤24 h. Seventeen participants (0.6 %) sought treatment for adverse effects. Fifty-six individuals (2 %) met DSM-5 criteria for a past-year moderate or severe kratom-related substance use disorder (SUD). When asked how troubled they felt regarding their kratom use, the mean (SD) rating was 3.2 (9.8) on a scale from 0 to 100.

CONCLUSION

Kratom is used among White, middle-aged Americans for symptoms of pain, anxiety, depression, and opioid withdrawal. Although regular use was typical, kratom-related SUD and serious adverse effects were uncommon. Additional research on kratom epidemiology and pharmacology is imperative in light of the present opioid epidemic.

Still Lost in Translation

Interdisciplinary dialogue can help progress and improve professional fields. Progress and improvement may be impeded by barriers within an interdisciplinary dialogue, two of which are false dichotomies and faulty generalizations. It is our opinion that this particular interdisciplinary dialogue will advance productively by avoiding: false dichotomies about the medical model and Disability Studies in Education (DSE) framework; false dichotomies about using a normality approach to establish goals; and faulty generalizations about practitioners within and outside the field in which we are trained. Most helping professionals care passionately about improving the quality of lives of the people with whom they work. Centering interdisciplinary conversations on this shared value can help avoid false dichotomies and faulty generalizations.

Verbal behavior and risky choice in humans: Exploring the boundaries of the description-experience gap

The description-experience (DE) gap is a tendency to prefer uncertain over certain rewards when experienced compared to described. DE gap research typically intermixes choice between two gains with choice between two losses. Because preference for uncertain gains have been found to increase following experienced loss, preference for uncertain gains (and the DE gap) may decrease when gains are presented in isolation. Experiment 1 examined the DE gap when participants were presented choices between gains (points) in isolation. Experiment 2 examined the DE gap when participants were presented with gains in isolation and intermixed with point losses. When gains were first contacted in isolation, participants chose the uncertain gain more when it was described compared to experienced (a reversed DE gap). But, when gains were intermixed with losses, participants chose the uncertain gain more when it was experienced compared to described (typical DE gap). Additional exposure to intermixed following isolated choices led to a typical DE gap, and exposure to isolated following intermixed choices decreased the size of the typical DE gap. These results show how choice with experienced or described outcomes is influenced by intermixing gains with losses and may reveal how the DE gap can be manipulated.

Function matters: a review of terminological differences in applied and basic clicker training research

In clicker training, animal trainers pair a small device (a “clicker”) with a reward when teaching or maintaining responding. Animal trainers often assume clicker training is a “science-based” way to train animals. But, the few studies that have compared clicker training to a control have not provided evidence that adding a clicker is beneficial to training. This may be because research on clicker training has studied only one of several potential functions of the clicker stimulus that have been discussed by animal trainers. A systematic approach to researching the function of the clicker in clicker training would benefit from collaboration between applied and basic researchers. However, this will require that terminological differences between animal trainers and basic researchers are reconciled. This paper reviews the few studies that have compared clicker training to a control group and then discusses how trainers and basic researchers use the same terminology in functionally different ways—suggesting the empirical support for mechanisms underlying clicker training is less robust than previously assumed. These differences highlight many opportunities to answer basic and applied research questions relative to clicker training methods. Advancements in clicker training methods will benefit animal trainers who have been using clicker training for decades as well as applied practitioners who have extended clicker training to humans in educational and clinical settings.

Further comparison of 5-trial adjusting delay and probability loss tasks over a wide range of amounts

Researchers have recently developed brief methods to measure discounting. One brief method uses 5-trial adjusting-delay or -probability tasks. These tasks have provided similar rates of discounting to traditional tasks with monetary gains, but the accuracy with losses have been mixed. Differences in loss discounting across tasks may have been due to the amounts used in previous experiments. Therefore, we had undergraduate students (N = 93) complete two types of discounting tasks across losses ranging from $10 to $10 million. Consistent with previous research using traditional measures, discounting did not differ between tasks or across amounts used. 5-trial discounting tasks of losses provide similar rates of discounting compared to traditional adjusting amount tasks for both probability and delay.

Lost in Translation: A Reply to Shyman (2016)

A recently published article sought to determine the extent to which behaviorism and humanism can be reconciled ( Shyman, 2016 ). However, the "current" conceptions of behaviorism and applied behavior analysis (ABA) used for the analysis were based on mischaracterizations, rendering moot many of the points made. Nevertheless, Shyman (2016) highlighted a very important question we believe all helping professionals should attend to: Should normalization be the focus of therapeutic goals? This response article was written to provide readers of this journal an accurate representation of behaviorism and ABA. We have also offered an alternative approach to answering the question of normalization that uses a behavior-by-behavior approach and individual client values as the deciding factors.

Search for the Exotic Meson X(5568) with the Collider Detector at Fermilab

A search for the exotic meson X(5568) decaying into the B_{s}^{0}π^{±} final state is performed using data corresponding to 9.6  fb^{-1} from pp[over ¯] collisions at sqrt[s]=1960  GeV recorded by the Collider Detector at Fermilab. No evidence for this state is found and an upper limit of 6.7% at the 95% confidence level is set on the fraction of B_{s}^{0} produced through the X(5568)→B_{s}^{0}π^{±} process.

How to Identify Ethical Practices in Organizations Prior to Employment

Behavior analysts likely can evaluate multiple organizations prior to accepting a job due to recent increases in the number of organizations providing ABA services. We argue that evaluating the ethical values of an organization is paramount during the job search process. We provide strategies for evaluating the ethical values of an organization prior to employment and describe considerations from the pre-application process through contract negotiations. Ultimately, we add to the growing body of literature that provides guidance for common problems behavior analysts may face over the course of their careers.

Combined Forward-Backward Asymmetry Measurements in Top-Antitop Quark Production at the Tevatron

The CDF and D0 experiments at the Fermilab Tevatron have measured the asymmetry between yields of forward- and backward-produced top and antitop quarks based on their rapidity difference and the asymmetry between their decay leptons. These measurements use the full data sets collected in proton-antiproton collisions at a center-of-mass energy of sqrt[s]=1.96  TeV. We report the results of combinations of the inclusive asymmetries and their differential dependencies on relevant kinematic quantities. The combined inclusive asymmetry is A_{FB}^{tt[over ¯]}=0.128±0.025. The combined inclusive and differential asymmetries are consistent with recent standard model predictions.

Differences in Delay, but not Probability Discounting, in Current Smokers, E-cigarette Users, and Never Smokers

Steeper delay discounting in substance abuse populations, compared to non-abusing populations, has been well-established in prior studies. Despite the growing interest in e-cigarettes as a novel and relatively understudied form of nicotine consumption, relatively little is known as to how e-cigarette users discount rewards compared to traditional cigarette smokers and never smokers. In the present study, we measured delay and probability discounting rates, as well as perceived risk inherent to a delayed reward, in current traditional cigarette smokers, e-cigarette users, and never smokers. We found that traditional cigarette smokers and e-cigarette users discounted delayed rewards at a similar rate—and both were steeper than never smokers. However, no differences were observed in probability discounting or in perceived risk inherent in reward delay.

A modified echocardiographic approach improves reliability of superior vena caval flow quantification

OBJECTIVE

To assess accuracy and repeatability of a modified echocardiographic approach to quantify superior vena cava (SVC) flow volume that uses a short-axis view to directly measure SVC area and a suprasternal view to measure flow velocity, both at the level of the right pulmonary artery.

SETTING

Three tertiary-level neonatal intensive care units.

DESIGN

This was a multicentre, prospective, observational study. Accuracy of the traditional and modified approach was first assessed by comparing echo measurements according to both techniques with Phase contrast MRI (PCMRI) assessments, in a cohort of 10 neonates. In a second cohort of 40 neonates, intraobserver scan-rescan repeatability and interobserver analysis-reanalysis repeatability were assessed by repeated SVC flow echo measurements, according to both techniques.

RESULTS

The traditional echocardiographic approach to assessment of SVC flow had a moderate agreement with PCMRI (r² 0.259), a scan-rescan intraobserver repeatability index (RI) of 37% (limits of agreement (LOA) -47/+51 mL/kg/min) and an interobserver analysis-reanalysis RI of 31% (LOA -38/+40 mL/kg/min). The modified approach showed a stronger agreement with PCMRI (r² 0.775), an improved intraobserver scan-rescan repeatability (RI 22%, LOA -24/+18 mL/kg/min) and improved interobserver analysis-reanalysis repeatability (RI 18%, LOA -18/+20 mL/kg/min).

CONCLUSIONS

Echocardiographic assessment of SVC flow volume by tracing area from a short-axis view and measuring velocity-time integral from a suprasternal view offered an improvement in accuracy and repeatability, building on the traditional approach previously described.

Effects of delay and probability combinations on discounting in humans

To determine discount rates, researchers typically adjust the amount of an immediate or certain option relative to a delayed or uncertain option. Because this adjusting amount method can be relatively time consuming, researchers have developed more efficient procedures. One such procedure is a 5-trial adjusting delay procedure, which measures the delay at which an amount of money loses half of its value (e.g., $1000 is valued at $500 with a 10-year delay to its receipt). Experiment 1 (n=212) used 5-trial adjusting delay or probability tasks to measure delay discounting of losses, probabilistic gains, and probabilistic losses. Experiment 2 (n=98) assessed combined probabilistic and delayed alternatives. In both experiments, we compared results from 5-trial adjusting delay or probability tasks to traditional adjusting amount procedures. Results suggest both procedures produced similar rates of probability and delay discounting in six out of seven comparisons. A magnitude effect consistent with previous research was observed for probabilistic gains and losses, but not for delayed losses. Results also suggest that delay and probability interact to determine the value of money. Five-trial methods may allow researchers to assess discounting more efficiently as well as study more complex choice scenarios.

Tevatron Combination of Single-Top-Quark Cross Sections and Determination of the Magnitude of the Cabibbo-Kobayashi-Maskawa Matrix Element V_{tb}

We present the final combination of CDF and D0 measurements of cross sections for single-top-quark production in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV. The data correspond to total integrated luminosities of up to 9.7 fb^{-1} per experiment. The t-channel cross section is measured to be σ_{t}=2.25_{-0.31}^{+0.29} pb. We also present the combinations of the two-dimensional measurements of the s- vs t-channel cross section. In addition, we give the combination of the s+t channel cross section measurement resulting in σ_{s+t}=3.30_{-0.40}^{+0.52} pb, without assuming the standard model value for the ratio σ_{s}/σ_{t}. The resulting value of the magnitude of the top-to-bottom quark coupling is |V_{tb}|=1.02_{-0.05}^{+0.06}, corresponding to |V_{tb}|>0.92 at the 95% C.L.

Search for Resonances Decaying to Top and Bottom Quarks with the CDF Experiment

We report on a search for charged massive resonances decaying to top (t) and bottom (b) quarks in the full data set of proton-antiproton collisions at a center-of-mass energy of √[s]=1.96  TeV collected by the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.5  fb(-1). No significant excess above the standard model background prediction is observed. We set 95% Bayesian credibility mass-dependent upper limits on the heavy charged-particle production cross section times branching ratio to tb. Using a standard model extension with a W'→tb and left-right-symmetric couplings as a benchmark model, we constrain the W' mass and couplings in the 300-900  GeV/c(2) range. The limits presented here are the most stringent for a charged resonance with mass in the range 300-600  GeV/c(2) decaying to top and bottom quarks.

Tevatron constraints on models of the Higgs boson with exotic spin and parity using decays to bottom-antibottom quark pairs

Combined constraints from the CDF and D0 Collaborations on models of the Higgs boson with exotic spin J and parity P are presented and compared with results obtained assuming the standard model value JP=0+. Both collaborations analyzed approximately 10  fb(-) of proton-antiproton collisions with a center-of-mass energy of 1.96 TeV collected at the Fermilab Tevatron. Two models predicting exotic Higgs bosons with JP=0- and JP=2+ are tested. The kinematic properties of exotic Higgs boson production in association with a vector boson differ from those predicted for the standard model Higgs boson. Upper limits at the 95% credibility level on the production rates of the exotic Higgs bosons, expressed as fractions of the standard model Higgs boson production rate, are set at 0.36 for both the JP=0- hypothesis and the JP=2+ hypothesis. If the production rate times the branching ratio to a bottom-antibottom pair is the same as that predicted for the standard model Higgs boson, then the exotic bosons are excluded with significances of 5.0 standard deviations and 4.9 standard deviations for the JP=0- and JP=2+ hypotheses, respectively.

Constraints on models of the Higgs boson with exotic spin and parity using decays to bottom-antibottom quarks in the full CDF data set

A search for particles with the same mass and couplings as those of the standard model Higgs boson but different spin and parity quantum numbers is presented. We test two specific alternative Higgs boson hypotheses: a pseudoscalar Higgs boson with spin-parity J^{P}=0^{-} and a gravitonlike Higgs boson with J^{P}=2^{+}, assuming for both a mass of 125  GeV/c^{2}. We search for these exotic states produced in association with a vector boson and decaying into a bottom-antibottom quark pair. The vector boson is reconstructed through its decay into an electron or muon pair, or an electron or muon and a neutrino, or it is inferred from an imbalance in total transverse momentum. We use expected kinematic differences between events containing exotic Higgs bosons and those containing standard model Higgs bosons. The data were collected by the CDF experiment at the Tevatron proton-antiproton collider, operating at a center-of-mass energy of sqrt[s]=1.96  TeV, and correspond to an integrated luminosity of 9.45  fb^{-1}. We exclude deviations from the predictions of the standard model with a Higgs boson of mass 125  GeV/c^{2} at the level of 5 standard deviations, assuming signal strengths for exotic boson production equal to the prediction for the standard model Higgs boson, and set upper limits of approximately 30% relative to the standard model rate on the possible rate of production of each exotic state.

Measurement of the single top quark production cross section and |Vtb| in events with one charged lepton, large missing transverse energy, and jets at CDF

We report a measurement of single top quark production in proton-antiproton collisions at a center-of-mass energy of sqrt[s]=1.96  TeV using a data set corresponding to 7.5  fb(-1) of integrated luminosity collected by the Collider Detector at Fermilab. We select events consistent with the single top quark decay process t→Wb→ℓνb by requiring the presence of an electron or muon, a large imbalance of transverse momentum indicating the presence of a neutrino, and two or three jets including at least one originating from a bottom quark. An artificial neural network is used to discriminate the signal from backgrounds. We measure a single top quark production cross section of 3.04(-0.53)(+0.57)  pb and set a lower limit on the magnitude of the coupling between the top quark and bottom quark |Vtb|>0.78 at the 95% credibility level.

Measurements of direct CP-violating asymmetries in charmless decays of bottom baryons

We report final measurements of direct CP-violating asymmetries in charmless decays of neutral bottom hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using the complete √s=1.96  TeV proton-antiproton collisions data set, corresponding to 9.3  fb⁻¹ of integrated luminosity, we measure A(Λ(b)⁰→pπ⁻)=+0.06±0.07(stat)±0.03(syst) and A(Λ(b)⁰→pK⁻)=-0.10±0.08(stat)±0.04(syst), compatible with no asymmetry. In addition we measure the CP-violating asymmetries in B(s)⁰→K⁻π⁺ and B⁰→K⁺π⁻ decays to be A(B(s)⁰→K⁻π⁺)=+0.22±0.07(stat)±0.02(syst) and A(B⁰→K⁺π⁻)=-0.083±0.013(stat)±0.004(syst), respectively, which are significantly different from zero and consistent with current world averages.

Measurement of the inclusive leptonic asymmetry in top-quark pairs that decay to two charged leptons at CDF

We measure the inclusive forward-backward asymmetry of the charged-lepton pseudorapidities from top-quark pairs produced in proton-antiproton collisions and decaying to final states that contain two charged leptons (electrons or muons). The data are collected with the Collider Detector at Fermilab and correspond to an integrated luminosity of 9.1 fb(-1). We measure the leptonic forward-backward asymmetry, A(FB)(ℓ), to be 0.072 ± 0.060 and the leptonic pair forward-backward asymmetry, A(FB)(ℓℓ), to be 0.076 ± 0.082. The measured values can be compared with the standard model predictions of A(FB)(ℓ) = 0.038 ± 0.003 and A(FB)(ℓℓ) = 0.048 ± 0.004, respectively. Additionally, we combine the A(FB)(ℓ) result with a previous determination from a final state with a single lepton and hadronic jets and obtain A(FB)(ℓ) = 0.090(-0.026)(+0.028).

Cardiovascular magnetic resonance of cardiac function and myocardial mass in preterm infants: a preliminary study of the impact of patent ductus arteriosus

BACKGROUND

Many pathologies seen in the preterm population are associated with abnormal blood supply, yet robust evaluation of preterm cardiac function is scarce and consequently normative ranges in this population are limited. The aim of this study was to quantify and validate left ventricular dimension and function in preterm infants using cardiovascular magnetic resonance (CMR). An initial investigation of the impact of the common congenital defect patent ductus arteriosus (PDA) was then carried out.

METHODS

Steady State Free Procession short axis stacks were acquired. Normative ranges of left ventricular end diastolic volume (EDV), stroke volume (SV), left ventricular output (LVO), ejection fraction (EF), left ventricular (LV) mass, wall thickness and fractional thickening were determined in "healthy" (control) neonates. Left ventricular parameters were then investigated in PDA infants. Unpaired student t-tests compared the 2 groups. Multiple linear regression analysis assessed impact of shunt volume in PDA infants, p-value ≤ 0.05 being significant.

RESULTS

29 control infants median (range) corrected gestational age at scan 34+6(31+1-39+3) weeks were scanned. EDV, SV, LVO, LV mass normalized by weight and EF were shown to decrease with increasing corrected gestational age (cGA) in controls. In 16 PDA infants (cGA 30+3(27+3-36+1) weeks) left ventricular dimension and output were significantly increased, yet there was no significant difference in ejection fraction and fractional thickening between the two groups. A significant association between shunt volume and increased left ventricular mass correcting for postnatal age and corrected gestational age existed.

CONCLUSION

CMR assessment of left ventricular function has been validated in neonates, providing more robust normative ranges of left ventricular dimension and function in this population. Initial investigation of PDA infants would suggest that function is relatively maintained.

Evidence for s-channel single-top-quark production in events with one charged lepton and two jets at CDF

We report evidence for s-channel single-top-quark production in proton-antiproton collisions at center-of-mass energy sqrt[s] = 1.96 TeV using a data set that corresponds to an integrated luminosity of 9.4 fb(-1) collected by the Collider Detector at Fermilab. We select events consistent with the s-channel process including two jets and one leptonically decaying W boson. The observed significance is 3.8 standard deviations with respect to the background-only prediction. Assuming a top-quark mass of 172.5 GeV/c(2), we measure the s-channel cross section to be 1.41(-0.42)(+0.44) pb.

Search for s-channel single-top-quark production in events with missing energy plus jets in pp collisions at sqrt[s] = 1.96 TeV

The first search for single-top-quark production from the exchange of an s-channel virtual W boson using events with an imbalance in the total transverse energy, b-tagged jets, and no identified leptons is presented. Assuming the electroweak production of top quarks of mass 172.5 GeV/c(2) in the s channel, a cross section of 1.12(-0.57)(+0.61) (stat+syst) pb with a significance of 1.9 standard deviations is measured. This measurement is combined with the result obtained from events with an imbalance in total transverse momentum, b-tagged jets, and exactly one identified lepton, yielding a cross section of 1.36(-0.32)(+0.37) (stat+syst) pb, with a significance of 4.2 standard deviations.

Observation of s-channel production of single top quarks at the Tevatron

We report the first observation of single-top-quark production in the s channel through the combination of the CDF and D0 measurements of the cross section in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV. The data correspond to total integrated luminosities of up to 9.7 fb(-1) per experiment. The measured cross section is σ(s) = 1.29(-0.24)(+0.26) pb. The probability of observing a statistical fluctuation of the background to a cross section of the observed size or larger is 1.8 × 10(-10), corresponding to a significance of 6.3 standard deviations for the presence of an s-channel contribution to the production of single-top quarks.

Measurement of B(t→Wb)/B(t→Wq) in top-quark-pair decays using dilepton events and the full CDF Run II data set

We present a measurement of the ratio of the top-quark branching fractions R=B(t→Wb)/B(t→Wq), where q represents any quark flavor, in events with two charged leptons, imbalance in total transverse energy, and at least two jets. The measurement uses proton-antiproton collision data at center-of-mass energy 1.96 TeV, corresponding to an integrated luminosity of 8.7  fb^{-1} collected with the Collider Detector at Fermilab during Run II of the Tevatron. We measure R to be 0.87±0.07, and extract the magnitude of the top-bottom quark coupling to be |V_{tb}|=0.93±0.04, assuming three generations of quarks. Under these assumptions, a lower limit of |V_{tb}|>0.85(0.87) at 95% (90%) credibility level is set.

First search for exotic Z Boson decays into photons and neutral pions in hadron collisions

A search for forbidden and exotic Z boson decays in the diphoton mass spectrum is presented for the first time in hadron collisions, based on data corresponding to 10.0 fb(-1) of integrated luminosity from proton-antiproton collisions at √s = 1.96 TeV collected by the CDF experiment. No evidence of signal is observed, and 95% credibility level Bayesian upper limits are set on the branching ratios of decays of the Z boson to a photon and neutral pion (which is detected as a photon), a pair of photons, and a pair of neutral pions. The observed branching ratio limits are 2.01 × 10(-5) for Z → π(0)γ, 1.46 × 10(-5) for Z → γγ, and 1.52 × 10(-5) for Z → π(0)π(0). The Z → π(0)γ and Z → γγ limits improve the most stringent results from other experiments by factors of 2.6 and 3.6, respectively. The Z → π(0)π(0) branching ratio limit is the first experimental result on this decay.