The use of propensity score methods has become ubiquitous in causal inference. At the heart of these methods is the positivity assumption. Violation of the positivity assumption leads to the presence of extreme propensity scoreweights when estimating average causal effects, which affects statistical inference. To circumvent this issue, trimming or truncating methods have been widely used. Unfortunately, these methods require that we pre-specify a threshold. There are anumber of alternative methods to deal with the lack of positivity when we estimate the average treatment effect (ATE). However, no other methods exist beyond trimming and truncation to deal with the same issue when the goal is to estimate theaverage treatment effect on the treated (ATT). In this article, we propose a propensity score weight-based alternative for the ATT, called overlap weighted average treatment effect on the treated. The appeal of our proposed method lies in its abilityto obtain similar or even better results than trimming and truncation while relaxing the constraint to choose an a priori threshold (or related measures). The performance of the proposed method is illustrated via a series of Monte Carlo simulationsand a data analysis on racial disparities in health care expenditures.

Anxiety and depression are often comorbid and chronic disorders. Previous research indicates that positivity relinquishment is a moderator of anxiety and depression, such that only anxious individuals who endorsed relinquishing positivity were also depressed. We sought to extend those findings by conducting three network analyses with self-report measures of anxiety, depression, activity avoidance, and perceived positivity of avoided activities (N = 104). We pre-registered our hypothesis for the first two networks that relinquishment of positivity would emerge as a central bridge symptom between anxiety and depressive symptoms. After combining redundant nodes, we estimated three networks and investigated the bridge symptoms in each network. Relinquishment of positivity bridged the symptom clusters in the first network, and avoidance of positivity was found to bridge the two symptom clusters of anxiety and depression in networks two and three. Additionally, an anhedonia circuit was uncovered in all three networks in which loss of interest/worthlessness, loss of energy, and loss of pleasure/pessimism connected to anxiety through relinquishment or avoidance. Our findings suggest that both relinquishment of positivity as well as avoidance of positivity could be potential pathways explaining the development and maintenance of anxiety and depression and should be properly targeted in treatment.

The number of Methicillin-resistant Staphylococcus aureus (MRSA) cases in communities and hospitals is on the rise worldwide. In this work, a nonlinear deterministic model for the dynamics of MRSA infection in society was developed to visualize the significance of awareness in interventions that could be applied in the prevention of transmission with and without optimal control. Positivity and uniqueness were verified for the proposed corruption model to identify the level of resolution of infection factors in society. Furthermore, how various parameters affect the reproductive number R 0 and sensitivity analysis of the proposed model was explored through mathematical techniques and figures. The global stability of model equilibria analysis was established by using Lyapunov functions with the first derivative test. A total of seven years of data gathered from a private hospital consisting of inpatients and outpatients of MRSA were used in this model for numerical simulations and for observing the dynamics of infection by using a non-standard finite difference (NSFD) scheme. When optimal control was applied as a second model, it was determined that increasing awareness of hand hygiene and wearing a mask were the key controlling measures to prevent the spread of community-acquired MRSA (CA-MRSA) and hospital-acquired MRSA (HA-MRSA). Lastly, it was concluded that both CA-MRSA and HA-MRSA cases are on the rise in the community, and increasing awareness concerning transmission is extremely significant in preventing further spread.

Competency-based teasing has been identified as a risk factor for children\'s depressive symptoms. However, the specific psychological mechanisms mediating this relationship are not well understood, especially in the context of Chinese culture. This study examined the relationship between competency-based teasing, subsequent depressive symptoms, and the possible mediating role of positivity in Chinese children by using parallel process latent growth curve modelling. Gender differences were also explored. A sample of 4376 Chinese children (55.1% boys; age: M = 9.98 years, SD = 0.88) completed measurements of the relevant constructs on five occasions across 2 years, using half-year intervals. The findings revealed that competency-based teasing was significantly positively associated with subsequent depressive symptoms in Chinese children. Furthermore, positivity mediated this relationship in girls, but not in boys. The results suggest that positivity-cultivating and gender-specific interventions may be effective to reduce the risk of depressive symptoms in Chinese children.

OBJECTIVE: Depression exerts significant negative impacts across various life domains, including social interactions, occupational functioning, and economic well-being. These effects permeate both personal and interpersonal spheres. However, it seems that character strengths, time perspective, and self-awareness play a critical role in promoting mental well-being. The present study aimed to investigate the effectiveness of positivity training on character strengths, time perspective, and self-awareness in depressed women.
METHODS: Purposive sampling was employed to select 50 participants with depression based on the cut-off point (a score of 20 or greater) in Beck\'s Depression Inventory (BDI-II). They were then randomly assigned to a control group (n = 25) and an experimental group (n = 25). This quasi-experimental research adopted a pretest-posttest control group design. The experimental group received eight weekly 90-min sessions of positivity training. The control group participants did not receive any specific intervention related to depression management. The character strength scale, time perspective scale, self-awareness scale, and BDI-II were used to collect data. Data analysis methods included descriptive statistics (mean and standard deviation) and inferential statistics (ANCOVA). Data analysis was conducted using SPSS software.
RESULTS: The study included a sample of 50 women diagnosed with Major Depressive Disorder (MDD). The participants\' mean age was 38.03 years (SD = 7.96). Positivity training enhanced character strengths in women with depression. Moreover, the positivity intervention affected the time perspective factors of those women. It reduced \"past negative\" and \"present fatalistic\" and increased \"past positive,\" \"present hedonistic,\" and \"future.\" Finally, positivity training significantly increased self-awareness in women with depression (p < 0.01).
CONCLUSIONS: The sample size was relatively small, which limits the statistical inferences.
CONCLUSIONS: In conclusion, this study provides promising initial evidence for the potential of positivity training as an intervention to improve character strengths, time perspective, and self-awareness in women with MDD. Further research is warranted to confirm and expand upon these findings, ultimately informing the development of more comprehensive treatment approaches for depression.

The accurate identification of individuals without prior infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is pivotal for seroepidemiological research and vaccine trials. Because of widespread COVID-19 vaccination, the anti-nucleocapsid antibody continues to serve as a valuable marker for individuals without a history of COVID-19. This study aimed to comprehensively assess anti-nucleocapsid antibody positivity using diverse commercial and in-house immunoassays among individuals who contracted COVID-19 more than 3 years ago. We enrolled 44 participants with laboratory-confirmed COVID-19 between January and May 2020 from Seoul National University Hospital and its community treatment centers. The results showed anti-nucleocapsid antibody positivities ranged from 45.5% to 87.9% depending upon the immunoassay used. The study highlights the importance of considering the limited anti-nucleocapsid antibody positivity in participants with a distant COVID-19 history in seroepidemiological or vaccine research.

Psychosocial dimensions are essential to guarantee an optimal approach to improve emotional well-being in patients with cardiovascular disease (CVD). There is evidence of sex differences regarding these dimensions. Thus, the connections between them are crucial to implement personalized therapies. Network model analyses were conducted on data from 593 CVD patients. The models included scores from the Hospital Anxiety and Depression Scale (HADS), positive (PA) and negative affect (NA), positivity (PS), satisfaction of life (SLS), social support (SS), self-efficacy on emotion regulation (RESE), cardiac self-efficacy (CSE) and the Short Form-12 Health Survey. The main sex differences were found in: PA-PS (p = 0.03), SS-RESE (p = 0.04), for which the positive associations are stronger for men than for women and PA-RESE (p < 0.01) for which the positive association is stronger for women than for men. These nuances should be considered to implement tailored and integrative therapies for each CVD patient.

We study a node-wise monotone barrier coupling law, motivated by the synaptic coupling of neural central pattern generators. It is illustrated that this coupling imitates the desirable properties of neural central pattern generators. In particular, the coupling law (1) allows us to assign multiple central patterns on the circle and (2) allows for rapid switching between different patterns via simple \'kicks\'. In the end, we achieve full control by partitioning the state space by utilizing a barrier effect and assigning a unique steady-state behavior to each element of the resulting partition. We analyze the global behavior and study the viability of the design.

This paper investigates a class of switched singular positive systems with time-varying delay, where the system parameters are uncertain. In order to decrease the consumption of the communication resources and avoid the phenomenon of data congestion, Round-Robin protocol is employed here. This is the first few attempts to introduce the Round-Robin protocol for such kind of positive systems. Moreover, the nonfragile controller is designed to suppress the undesired dynamical behaviors, which may occur if no control is implemented. By means of the matrix decomposition technique and the mode-dependent average dwell time method, sufficient conditions are established to ensure that the obtained closed-loop system has a prescribed l1 disturbance attenuation performance. Finally, three examples are presented to illustrate feasibility and effectiveness of the proposed control scheme.

UNASSIGNED: To demonstrate that using an instrumental variable (IV) with monotonicity reduces the accuracy of propensity score (PS) weighted estimators for the average treatment effect (ATE).
UNASSIGNED: Monotonicity in the relationship between a binary IV and a binary treatment variable is an important assumption to identify the ATE for compliers who would only take treatment when encouraged by the IV. We perform theoretical and numerical investigations to study the impact of using the IV that satisfies monotonicity on the PS of treatment in terms of the positivity assumption, which requires that the PS be strictly between 0 and 1, and the accuracy of PS weighted estimators. Two versions of monotonicity that result in one-sided or two-sided noncompliance are considered.
UNASSIGNED: The PS adjusting for the IV always violates the positivity assumption when noncompliance occurs in one direction (one-sided noncompliance) and is more extreme than without the IV under two-sided noncompliance. These results are valid if the probability of being encouraged to get treatment and the compliance score, the probability of being a complier, are strictly between 0 and 1.
UNASSIGNED: Using a binary IV with monotonicity as a covariate for the PS model makes the estimated PSs unnecessarily extreme, reducing the accuracy of the PS weighted estimators.