437 research outputs found
Nicotine-evoked conditioned responding is dependent on concentration of sucrose unconditioned stimulus
Previous studies have shown that the interoceptive nicotine conditional stimulus (CS) functions similarly to exteroceptive CSs such as lights or environments. For instance, the appetitive conditioned response (CR) evoked when nicotine is repeatedly paired with sucrose presentations (the unconditioned stimulus; US) is sensitive to changes in training dose (CS salience) and the contiguity between the CS effects and sucrose. The current study was conducted to extend this research by examining the possible role of US intensity in CR acquisition and maintenance. Rats were trained using one of four sucrose concentrations: 0, 4, 16, or 32% (w/v). On nicotine sessions (0.4 mg base/kg), rats received 36 deliveries (4 sec each) of their assigned concentration intermittently throughout the session; sucrose was withheld on saline sessions. In all groups, an appetitive goal-tracking CR was acquired at a similar rate. However, the asymptotic CR level varied with sucrose concentration. The magnitude of the CR was increased in rats trained with higher sucrose US concentrations. These findings are consistent with previous Pavlovian conditioning research, and extend the conditions under which the nicotine state functions as an interoceptive conditional stimulus
Mugshot Exposure Effects: Retroactive Interference, Mugshot Commitment, Source Confusion, and Unconscious Transference
More than 25 years of research has accumulated concerning the possible biasing effects of mugshot exposure to eyewitnesses. Two separate metaanalyses were conducted on 32 independent tests of the hypothesis that prior mugshot exposure decreases witness accuracy at a subsequent lineup. Mugshot exposure both significantly decreased proportion correct and increased the false alarm rate, the effect being greater on false alarms. A mugshot commitment effect, arising from the identification of someone in a mugshot, was a substantial moderator of both these effects. Simple retroactive interference, where the target person is not included among mugshots and no one in a mugshot is present in the subsequent lineup, did not significantly impair target identification. A third metaanalysis was conducted on 19 independent tests of the hypothesis that failure of memory for facial source or context results in transference errors. The effect size was more than twice as large for “transference” studies involving mugshot exposure in proximate temporal context with the target than for “bystander” studies with no subsequent mugshot exposure
Why Criminal Defendants Cooperate: The Defense Attorney\u27s Perspective
Cooperation is at the heart of most complex federal criminal cases, with profound ramifications for who can be brought to justice and for the fate of those who decide to cooperate. But despite the significance of cooperation, scholars have yet to explore exactly how individuals confronted with the decision whether to pursue cooperation with prosecutors make that choice. This Article—the first empirical study of the defense experience of cooperation—begins to address that gap. The Article reports the results of a survey completed by 146 criminal defense attorneys in three federal districts: the Southern District of New York, the Eastern District of Virginia, and the Eastern District of Pennsylvania. Our study provides an entirely new and enriching perspective on the cooperation decision, building on prior theories from the cooperation and plea-bargaining literature, and providing for a more nuanced understanding of cooperation and its motivations. In several closed- and open-ended responses, attorneys shared their opinions—at times remarkably consistent, at times strikingly and informatively different—about cooperation practices in their respective districts. The results of this study can be used to further explore the theoretical foundations of cooperation and plea bargaining and can be used to build experimental studies to test causal relationships that are otherwise nearly impossible to determine
A Meta-Analytic Review of the Effects of High Stress on Eyewitness Memory
In the past 30 years researchers have examined the impact of heightened stress on the fidelity of eyewitness memory. Meta-analyses were conducted on 27 independent tests of the effects of heightened stress on eyewitness identification of the perpetrator or target person and separately on 36 tests of eyewitness recall of details associated with the crime. There was considerable support for the hypothesis that high levels of stress negatively impact both types of eyewitness memory. Meta-analytic Z-scores, whether unweighted or weighted by sample size, ranged from -5.40 to -6.44 (high stress condition–low stress condition). The overall effect sizes were -.31 for both proportion of correct identifications and accuracy of eyewitness recall. Effect sizes were notably larger for target-present than for target-absent lineups, for eyewitness identification studies than for face recognition studies and for eyewitness studies employing a staged crime than for eyewitness studies employing other means to induce stress
A Meta-Analytic Review of the Effects of High Stress on Eyewitness Memory
In the past 30 years researchers have examined the impact of heightened stress on the fidelity of eyewitness memory. Meta-analyses were conducted on 27 independent tests of the effects of heightened stress on eyewitness identification of the perpetrator or target person and separately on 36 tests of eyewitness recall of details associated with the crime. There was considerable support for the hypothesis that high levels of stress negatively impact both types of eyewitness memory. Meta-analytic Z-scores, whether unweighted or weighted by sample size, ranged from -5.40 to -6.44 (high stress condition–low stress condition). The overall effect sizes were -.31 for both proportion of correct identifications and accuracy of eyewitness recall. Effect sizes were notably larger for target-present than for target-absent lineups, for eyewitness identification studies than for face recognition studies and for eyewitness studies employing a staged crime than for eyewitness studies employing other means to induce stress
Epistatic Interactions in Genetic Regulation of t-PA and PAI-1 Levels in a Ghanaian Population
The proteins, tissue plasminogen activator (t-PA) and plasminogen activator inhibitor 1 (PAI-1), act in concert to balance thrombus formation and degradation, thereby modulating the development of arterial thrombosis and excessive bleeding. PAI-1 is upregulated by the renin-angiotensin system (RAS), specifically by angiotensin II, the product of angiotensin converting enzyme (ACE) cleavage of angiotensin I, which is produced by the cleavage of angiotensinogen (AGT) by renin (REN). ACE indirectly stimulates the release of t-PA which, in turn, activates the corresponding fibrinolytic system. Single polymorphisms in these pathways have been shown to significantly impact plasma levels of t-PA and PAI-1 differently in Ghanaian males and females. Here we explore the involvement of epistatic interactions between the same polymorphisms in central genes of the RAS and fibrinolytic systems on plasma t-PA and PAI-1 levels within the same population (n = 992). Statistical modeling of pairwise interactions was done using two-way ANOVA between polymorphisms in the ETNK2, RENIN, ACE, PAI-1, t-PA, and AGT genes. The most significant interactions that associated with t-PA levels were between the ETNK2 A6135G and the REN T9435C polymorphisms in females (p = 0.006) and the REN T9435C and the TPA I/D polymorphisms (p = 0.005) in males. The most significant interactions for PAI-1 levels were with REN T9435C and the TPA I/D polymorphisms (p = 0.001) in females, and the association of REN G6567T with the TPA I/D polymorphisms (p = 0.032) in males. Our results provide evidence for multiple genetic effects that may not be detected using single SNP analysis. Because t-PA and PAI-1 have been implicated in cardiovascular disease these results support the idea that the genetic architecture of cardiovascular disease is complex. Therefore, it is necessary to consider the relationship between interacting polymorphisms of pathway specific genes that predict t-PA and PAI-1 levels
Pathological Response in Resectable Non-small Cell Lung Cancer: A Systematic Literature Review and Meta-Analysis
BACKGROUND: Surrogate endpoints for overall survival in patients with resectable non-small cell lung cancer receiving neoadjuvant therapy are needed to provide earlier treatment outcome indicators and accelerate drug approval. This study\u27s main objectives were to investigate the association among pathological complete response, major pathological response, event-free survival and overall survival and to determine whether treatment effects on pathological complete response and event-free survival correlate with treatment effects on overall survival.
METHODS: A comprehensive systematic literature review was conducted to identify neoadjuvant studies in resectable non-small cell lung cancer. Analysis at the patient level using frequentist and Bayesian random effects (hazard ratio [HR] for overall survival or event-free survival by pathological complete response or major pathological response status, yes vs no) and at the trial level using weighted least squares regressions (hazard ratio for overall survival or event-free survival vs pathological complete response, by treatment arm) were performed.
RESULTS: In both meta-analyses, pathological complete response yielded favorable overall survival compared with no pathological complete response (frequentist, 20 studies and 6530 patients: HR = 0.49, 95% confidence interval = 0.42 to 0.57; Bayesian, 19 studies and 5988 patients: HR = 0.48, 95% probability interval = 0.43 to 0.55) and similarly for major pathological response (frequentist, 12 studies and 1193 patients: HR = 0.36, 95% confidence interval = 0.29 to 0.44; Bayesian, 11 studies and 1018 patients: HR = 0.33, 95% probability interval = 0.26 to 0.42). Across subgroups, estimates consistently showed better overall survival or event-free survival in pathological complete response or major pathological response compared with no pathological complete response or no major pathological response. Trial-level analyses showed a moderate to strong correlation between event-free survival and overall survival hazard ratios (R2 = 0.7159) but did not show a correlation between treatment effects on pathological complete response and overall survival or event-free survival.
CONCLUSION: There was a strong and consistent association between pathological response and survival and a moderate to strong correlation between event-free survival and overall survival following neoadjuvant therapy for patients with resectable non-small cell lung cancer
Use of Advanced Flexible Modeling Approaches for Survival Extrapolation from Early Follow-up Data in two Nivolumab Trials in Advanced NSCLC with Extended Follow-up
Objectives: Immuno-oncology (IO) therapies are often associated with delayed responses that are deep and durable, manifesting as long-term survival benefits in patients with metastatic cancer. Complex hazard functions arising from IO treatments may limit the accuracy of extrapolations from standard parametric models (SPMs). We evaluated the ability of flexible parametric models (FPMs) to improve survival extrapolations using data from 2 trials involving patients with non–small-cell lung cancer (NSCLC). Methods: Our analyses used consecutive database locks (DBLs) at 2-, 3-, and 5-y minimum follow-up from trials evaluating nivolumab versus docetaxel in patients with pretreated metastatic squamous (CheckMate-017) and nonsquamous (CheckMate-057) NSCLC. For each DBL, SPMs, as well as 3 FPMs—landmark response models (LRMs), mixture cure models (MCMs), and Bayesian multiparameter evidence synthesis (B-MPES)—were estimated on nivolumab overall survival (OS). The performance of each parametric model was assessed by comparing milestone restricted mean survival times (RMSTs) and survival probabilities with results obtained from externally validated SPMs. Results: For the 2- and 3-y DBLs of both trials, all models tended to underestimate 5-y OS. Predictions from nonvalidated SPMs fitted to the 2-y DBLs were highly unreliable, whereas extrapolations from FPMs were much more consistent between models fitted to successive DBLs. For CheckMate-017, in which an apparent survival plateau emerges in the 3-y DBL, MCMs fitted to this DBL estimated 5-y OS most accurately (11.6% v. 12.3% observed), and long-term predictions were similar to those from the 5-y validated SPM (20-y RMST: 30.2 v. 30.5 mo). For CheckMate-057, where there is no clear evidence of a survival plateau in the early DBLs, only B-MPES was able to accurately predict 5-y OS (14.1% v. 14.0% observed [3-y DBL]). Conclusions: We demonstrate that the use of FPMs for modeling OS in NSCLC patients from early follow-up data can yield accurate estimates for RMST observed with longer follow-up and provide similar long-term extrapolations to externally validated SPMs based on later data cuts. B-MPES generated reasonable predictions even when fitted to the 2-y DBLs of the studies, whereas MCMs were more reliant on longer-term data to estimate a plateau and therefore performed better from 3 y. Generally, LRM extrapolations were less reliable than those from alternative FPMs and validated SPMs but remained superior to nonvalidated SPMs. Our work demonstrates the potential benefits of using advanced parametric models that incorporate external data sources, such as B-MPES and MCMs, to allow for accurate evaluation of treatment clinical and cost-effectiveness from trial data with limited follow-up. Flexible advanced parametric modeling methods can provide improved survival extrapolations for immuno-oncology cost-effectiveness in health technology assessments from early clinical trial data that better anticipate extended follow-up. Advantages include leveraging additional observable trial data, the systematic integration of external data, and more detailed modeling of underlying processes. Bayesian multiparameter evidence synthesis performed particularly well, with well-matched external data. Mixture cure models also performed well but may require relatively longer follow-up to identify an emergent plateau, depending on the specific setting. Landmark response models offered marginal benefits in this scenario and may require greater numbers in each response group and/or increased follow-up to support improved extrapolation within each subgroup
'Reaching the hard to reach' - lessons learned from the VCS (voluntary and community Sector). A qualitative study.
Background The notion 'hard to reach' is a contested and ambiguous term that is commonly used within the spheres of social care and health, especially in discourse around health and social inequalities. There is a need to address health inequalities and to engage in services the marginalized and socially excluded sectors of society. Methods This paper describes a pilot study involving interviews with representatives from eight Voluntary and Community Sector (VCS) organisations . The purpose of the study was to explore the notion of 'hard to reach' and perceptions of the barriers and facilitators to accessing services for 'hard to reach' groups from a voluntary and community sector perspective. Results The 'hard to reach' may include drug users, people living with HIV, people from sexual minority communities, asylum seekers, refugees, people from black and ethnic minority communities, and homeless people although defining the notion of the 'hard to reach' is not straight forward. It may be that certain groups resist engaging in treatment services and are deemed hard to reach by a particular service or from a societal stance. There are a number of potential barriers for people who may try and access services, including people having bad experiences in the past; location and opening times of services and how services are funded and managed. A number of areas of commonality are found in terms of how access to services for 'hard to reach' individuals and groups could be improved including: respectful treatment of service users, establishing trust with service users, offering service flexibility, partnership working with other organisations and harnessing service user involvement.
Conclusions: If health services are to engage with groups that are deemed 'hard to reach' and marginalised from mainstream health services, the experiences and practices for engagement from within the VCS may serve as useful lessons for service improvement for statutory health services
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