Longitudinal Multilevel Analyses Research Articles

Do peers matter? The influence of peers' self-regulation on individual self-regulation: a longitudinal multilevel analysis

Introduction:Self-regulation is important for social as well as academic success, and research shows that it is also shaped by social interactions. At the same time, peers shape children's development in many domains. Linking these two concepts, it can be predicted that children who are surrounded by peers with a high level of self-regulation later show higher self-regulation themselves compared to those who are surrounded by peers with a low level of self-regulation.MethodsTo test this assumption, a longitudinal sample with N = 1,658 participants in 181 classrooms (μage = 8.37) was analyzed. The self-regulation facets of working memory updating, inhibition, and flexibility were measured using an age-appropriate version of the Stroop test, the repeat-digits-backward test, and the Wisconsin card-sorting task. Based on this data, a score for both the individual and class level was calculated.ResultsThe results show that the classmates‘ level of self-regulation predicted later individual self-regulation above the individual self-regulation score. While neither age nor gender moderated this relationship, there was a significant cross-level interaction: Especially individuals with a low level of cognitive flexibility gained from being surrounded by peers with a high level of cognitive flexibility.DiscussionWhile the results show that peers constitute an important social context for the development of self-regulation, this fact is often only a minor point in modern self-regulation theories.

Multilevel Longitudinal Functional Principal Component Model.

Sensor devices, such as accelerometers, are widely used for measuring physical activity (PA). These devices provide outputs at fine granularity (e.g., 10-100Hz or minute-level), which while providing rich data on activity patterns, also pose computational challenges with multilevel densely sampled data, resulting in PA records that are measured continuously across multiple days and visits. On the other hand, a scalar health outcome (e.g., BMI) is usually observed only at the individual or visit level. This leads to a discrepancy in numbers of nested levels between the predictors (PA) and outcomes, raising analytic challenges. To address this issue, we proposed a multilevel longitudinal functional principal component analysis (mLFPCA) model to directly model multilevel functional PA inputs in a longitudinal study, and then implemented a longitudinal functional principal component regression (FPCR) to explore the association between PA and obesity-related health outcomes. Additionally, we conducted a comprehensive simulation study to examine the impact of imbalanced multilevel data on both mLFPCA and FPCR performance and offer guidelines for selecting optimal methods.

Prolonged perceived stress predicts fingernail cortisol increase: A longitudinal study

Cortisol levels in fingernail samples are known to represent cumulative hormone levels. However, findings on the association between fingernail cortisol and perceived stress have been inconsistent. Since the effect of confounding factors cannot be excluded in cross-sectional studies, this study longitudinally examined the effects of perceived stress and negative life events on changes in fingernail cortisol levels over a period of six months. In total, 113 university students rated their perceived stress and negative life events twice, fingernail samples were collected every 15 days during a six-month period. Furthermore, fingernail cortisol levels were quantified according to each stress and negative life event assessment. We conducted longitudinal multilevel analyses to estimate the effects of perceived stress and negative life events in changes within an individual (within-person change) as well as individual differences of them over the study period (between-person level) on changes in fingernail cortisol levels. Within-person increase in perceived stress and negative life events did not significantly predict within-person increase in fingernail cortisol levels. In the between-person level, higher average levels of negative life events did not significantly predict the rate of increase in fingernail cortisol levels than those with lower levels. However, individuals with higher average levels of perceived stress showed a steeper slope of time in fingernail cortisol levels. These findings suggest that prolonged high levels of perceived stress may be associated with fingernail cortisol levels.

The Role of Physical Literacy in the Association Between Weather and Physical Activity: A Longitudinal Multilevel Analysis With 951 Children.

Numerous studies showed an effect of weather on physical activity (PA) levels in children. However, no study has yet examined the relevance of personal factors in this relationship. Therefore, this study analyzes (1) whether there are systematic interindividual differences in the extent to which weather affects the PA behavior and (2) whether physical literacy (PL) moderates the weather-PA association in children. A total of 951 children in 12 Danish schools (age 9.76 [1.59]y; 54.3% girls) completed objective PA assessments via accelerometry (moderate to vigorous PA, light PA, and sedentary behavior). Local weather data (precipitation, wind speed, temperature, and sunshine duration) were provided by the Danish Meteorological Institute. Participants' PL was measured employing the Danish version of the Canadian Assessment of Physical Literacy-2. The 4116 accelerometer days underwent longitudinal multilevel analyses while considering their nesting into pupils and school classes (n = 51). Fluctuations in all PA indicators were significantly explained by variations in weather conditions, especially precipitation (P ≤ .035). Significant interindividual differences were found for 9 of 12 analytical dimensions, suggesting that weather changes influence PA behavior differently across individuals (especially moderate to vigorous PA, χ2[4] ≥ 11.5, P ≤ .021). However, PL moderated the relationship between weather and PA in only 2 of the 48 analytical constellations. Despite the varying impact of weather on PA across individuals, the present study favors a main effect model in which weather and PL exert independent effects on children's PA. The insufficient support for PL as a moderating factor calls for future studies to test alternative mechanisms in the weather-PA association.

Association of estimated plasma volume with new onset acute kidney injury in hospitalized COVID-19 patients

PurposeTo explore the association of estimated plasma volume (ePV) and plasma volume status (PVS) as surrogates of volume status with new-onset AKI and in-hospital mortality among hospitalized COVID-19 patients. Materials and methodsWe performed a retrospective multi-center study on COVID-19-related ARDS patients who were admitted to the Mayo Clinic Enterprise health system. Plasma volume was calculated using the formulae for ePV and PVS, and longitudinal analysis was performed to find the association of ePV and PVS with new-onset AKI during hospitalization as the primary outcome and in-hospital mortality as a secondary outcome. ResultsOur analysis included 7616 COVID-19 patients with new-onset AKI occurring in 1365 (17.9 %) and a mortality rate of 25.96 % among them. A longitudinal multilevel multivariate analysis showed both ePV (OR 1.162; 95 % CI 1.048–1.288, p = 0.004) and PVS (OR 1.032; 95 % CI 1.012–1.050, p = 0.001) were independent predictors of new onset AKI. Higher PVS was independently associated with increased in-hospital mortality (OR 1.038, 95 % CI 1.007–1.070, p = 0.017), but not ePV (OR 0.868, 95 % CI 0.740–1.018, p = 0.082). ConclusionA higher PVS correlated with a higher incidence of new-onset AKI and worse outcomes in our cohort of hospitalized COVID-19 patients. Further large-scale and prospective studies are needed to understand its utility.

Intersectional inequalities in the transition to grandparenthood and cognitive functioning: A longitudinal Multilevel Analysis of Individual Heterogeneity and Discriminatory Accuracy (MAIHDA).

In aging societies, more people become vulnerable to experiencing cognitive decline. Simultaneously, the role of grandparenthood is central for older adults and their families. Our study investigates inequalities in the level and trajectories of cognitive functioning among older adults, focusing on possible intersectional effects of social determinants and grandparenthood as a life course transition that may contribute to delaying cognitive decline. Using longitudinal data from the Survey of Health, Ageing and Retirement in Europe, we analyzed a sample of 19,953 individuals aged 50-85 without grandchildren at baseline. We applied Multilevel Analysis of Individual Heterogeneity and Discriminatory Accuracy to investigate variation in cognitive functioning across 48 intersectional strata, defined by sex/gender, migration, education, and occupation. We allowed the impact of becoming a grandparent on cognitive functioning trajectories to vary across strata by including random slopes. Intersectional strata accounted for 17.43% of the overall variance in cognitive functioning, with most of the stratum-level variation explained by additive effects of the stratum-defining characteristics. Transition to grandparenthood was associated with higher cognitive functioning, showing a stronger effect for women. Stratum-level variation in the grandparenthood effect was modest, especially after accounting for interactions between grandparenthood and the stratum-defining variables. This study highlights the importance of social determinants for understanding heterogeneities in older adults' level of cognitive functioning and its association with the transition to grandparenthood. Cumulative disadvantages negatively affect cognitive functioning, hence adopting an intersectional lens is useful to decompose inequalities and derive tailored interventions to promote equal healthy aging.

The effect of teacher self-efficacy in behaviour management on classroom behavioural climate: a longitudinal multilevel cross-lagged analysis

Teacher self-efficacy (TSE) is assumed to affect classroom environment, although empirical evidence for this assumption is still elusive. This study examines the relationship between TSE in behaviour management and classroom behavioural climate using a two-level cross-lagged model. TSE in behaviour management was assessed with six-item subscale of the TSE for Inclusive Practices scale while classroom behavioural climate was assessed with a 17-item scale measuring overall behavioural climate in the classroom. The longitudinal questionnaire data comprises responses from 1110 students and 75 class teachers who had not taught the target classes when the pre-assessment was conducted. At the time of post-assessment, the teachers had taught the target classes for a few months. This design may detect associations between TSE and classroom behavioural climate more sensitively than cross-lagged models were the main variables correlate already at the pre-assessment. Based on the analysis TSE in behaviour management significantly affected classroom behavioural climate, but not vice versa, when controlling the effect of several teacher characteristics and class-composition variables. This indicates that a connection between TSE and classroom behavioural climate seems to indeed exist.

Reducing suicides in mental healthcare: results from a 4-year follow-up implementation study in the Netherlands (SUPRANET).

In 2016, the SUicide PRevention Action NETwork (SUPRANET) was launched. The SUPRANET intervention aims at better implementing the suicide prevention guideline. An implementation study was developed to evaluate the impact of SUPRANET over time on three outcomes: 1) suicides, 2) registration of suicide attempts, and 3) professionals' knowledge and adherence to the guideline. This study included 13 institutions, and used an uncontrolled longitudinal prospective design, collecting biannual data on a 2-level structure (institutional and team level). Suicides and suicide attempts were extracted from data systems. Professionals' knowledge and adherence were measured using a self-report questionnaire. A three-step interrupted time series analysis (ITSA) was performed for the first two outcomes. Step 1 assessed whether institutions executed the SUPRANET intervention as intended. Step 2 examined if institutions complied with the four guideline recommendations. Based on steps 1 and 2, institutions were classified as below or above average and after that, included as moderators in step 3 to examine the effect of SUPRANET over time compared to the baseline. The third outcome was analyzed with a longitudinal multilevel regression analysis, and tested for moderation. After institutions were labeled based on their efforts and investments made (below average vs above average), we found no statistically significant difference in suicides (standardized mortality ratio) between the two groups relative to the baseline. Institutions labeled as above average did register significantly more suicide attempts directly after the start of the intervention (78.8 per 100,000 patients, p<0.001, 95%CI=(51.3 per 100,000, 106.4 per 100,000)), and as the study progressed, they continued to report a significantly greater improvement in the number of registered attempts compared with institutions assigned as below average (8.7 per 100,000 patients per half year, p=0.004, 95%CI=(3.3 per 100,000, 14.1 per 100,000)). Professionals working at institutions that invested more in the SUPRANET activities adhered significantly better to the guideline over time (b=1.39, 95%CI=(0.12,2.65), p=0.032). Institutions labeled as above average registered significantly more suicide attempts and also better adhered to the guideline compared with institutions that had performed less well. Although no convincing intervention effect on suicides was found within the study period, we do think that this network is potentially able to reduce suicides. Continuous investments and fully implementing as many guideline recommendations as possible are essential to achieve the biggest drop in suicides.

Economic Threats, Political and National Identification Predict Affective Polarization: Longitudinal Evidence From Spain

Economic threats, along with political identities and ideologies, are associated with affective polarization. However, there is still a need to learn more about the consequences of different economic threats and identities fueling polarization. We take a longitudinal perspective in testing the influence of these phenomena on affective polarization. Specifically, we tested the effect of subjective personal and collective economic threats and political, national, regional, and European identities on affective polarization towards politicians and partisans in Spain. We use four waves of the E-DEM panel study from Spain (N = 2,501) collected between 2018 and 2019. We conducted longitudinal multilevel analyses to determine the growth in affective polarization and included predictors at the between- and within-person levels. Consistent with our hypotheses, we found that collective economic threats, such as perceiving more unfairness in the distribution of wealth and being dissatisfied with the Spanish economy, positively predict affective polarization. Contrary to our expectations, personal economic threats did not predict affective polarization. Furthermore, political and national identities positively predicted affective polarization towards politicians and partisans. Interestingly, exploratory analyses suggested that the associations between economic threats, identities, and affective polarization are moderated by political ideology. We discuss how economic threats and identities may exacerbate animosities toward political actors.

Differential long-term effects of a language-based professional development program on instructional support quality

ABSTRACT The present study focused on the differential effects of two German PD programs in the ECEC field. We examined whether PD programs are equally effective for all ECEC professionals or whether ECEC professionals benefit differently from these learning opportunities. An experimental pre-post-follow-up study was conducted in the field with random assignment of participants (N = 50) to one of two language-based PD programs. In addition, transfer-relevant factors (transfer motivation, self-efficacy, support from supervisors and colleagues) were taken into account to investigate whether possible differences in changes in the quality of instructional support were related to the transfer conditions. Using longitudinal multilevel analyses, we found that the PD program “Talking with Children”, which focuses on language promotion strategies, is equally effective for all participants. Even with minimal perceived support from colleagues and supervisors, strategies learned in the PD program can be implemented to improve the quality of instructional support. Our results suggest the importance of considering transfer conditions to better support ECEC professionals in implementing what they have learned in PD programs in the future.

Revisiting the Three Basic Dimensions model: A critical empirical investigation of the indirect effects between perceived teaching quality and student outcomes

The Three Basic Dimensions (TBD) model, the leading model of teaching quality in German-speaking countries, theorizes three mediation paths for the effect of teaching quality on student outcomes. However, the existence of these paths and their effects have largely not been empirically tested. This study investigated the mediating role of depth-of-processing, time-on-task, and need satisfaction between student-rated teaching quality and students’ mathematics achievement and interest, expanding the TBD model to include mediation paths suggested by theories of motivation, cognition, and effort. Data from the TALIS Video Study Germany, comprising 958 secondary school students in 41 classrooms, were used to run multilevel longitudinal and correlational mediation analyses. The results found mediation effects only at the student level; there were no mediating effects at the classroom level. Not all of the hypothetical relationships thought to exist between the mediators and achievement and interest outcomes were confirmed. Specifically, at the student level, we found that time-on-task predicted student interest and depth of processing predicted student achievement, but none of the other hypothesized relationships were observed. The conceptual sequence of the variables, the choice of correlational vs. longitudinal evidence, and the level of analysis were all shown to have an impact on the results. The study thus confirms some of the assumptions of the TBD model, identifies new paths between teaching quality and student outcomes, and provides suggestions for how to proceed with the further investigation of a model which should be expanded and empirically tested.

Longitudinal Follow-Up Study of Social Intervention Outcomes for Children on the Autism Spectrum.

A prior randomized trial found a school social intervention yielded significantly better outcomes (social and autism features) immediately following intervention compared to typical school programming (services-as-usual [SAU]) for children on the autism spectrum. In that study, children in the SAU condition subsequently completed a summer social intervention. This study tested longer-term maintenance of effects for children who completed both interventions. A total of 103 children (ages 6-12 years) on the autism spectrum enrolled and 102 completed the initial RCT. Following the summer social intervention, 90 children from the original RCT completed the longer-term follow-up study. In addition to baseline and posttest in the initial RCT, children from both groups were tested at three follow-up points (five total testing points). At the time of first longitudinal follow-up testing, the children were 1.25-4.25 years post-intervention (ages 8-15 years). Longitudinal multilevel model analyses (and follow-up contrasts) revealed significant improvements for both groups post-intervention on measures of emotion recognition, autism features, and social skills, indicating maintenance of post-intervention improvements over the three follow-up testing points. No between-group differences were found for autism features or social skills over time; however, the school social intervention may have yielded somewhat better emotion recognition skills. Exploratory tests found that child IQ, language level, and length of time since completing the intervention did not moderate outcomes. Both social interventions yielded positive and durable longer-term improvements for children on the autism spectrum. [ClinicalTrials.gov, NCT03338530; November 8, 2017; original retrospectively registered trial].

A Longitudinal Multilevel Analysis of the Effects of Contraceptive Failures on Unintended Pregnancies among Women in Urban Nigeria.

Unintended pregnancy is a global public health concern. However, the effect of contraceptive failure on unintended pregnancy remains unclear in Nigeria. We undertook a longitudinal analysis to examine the effect of contraceptive failure on unintended pregnancy among urban women in Nigeria. We used panel data from the Nigerian Urban Reproductive Health Initiative. The Measurement, Learning and Evaluation program conducted the surveys among a cohort of women aged 15-49 who were first interviewed at baseline in 2010/2011 and followed up at endline in 2014/2015. Analytic sample was 4140 women aged 15-49 who ever used contraceptives. We fitted three-level multilevel binary logistic regression models estimated with GLLAMM. The study established evidence that there is a significant effect of contraceptive failure on unintended pregnancy among urban women in Nigeria. The positive effect of between-person contraceptive failure indicates that respondents who experienced more contraceptive failure than the average in the sample had 5.26 times higher odds of unintended pregnancy (OR = 5.26; p-value < 0.001). Results also established a significant effect of within-person contraceptive failures among the respondents. Findings suggest there is evidence of a significant longitudinal effect of contraceptive failure on unintended pregnancy in urban Nigeria. Efforts to reduce unintended pregnancy must include interventions to address the problem of contraceptive failure among urban women in Nigeria.

Down and out? the role of household income in students’ friendship formation in school-classes

Research suggests that coming from a lower economic background compromises social integration at school, yet the precise mechanisms underlying this link remain unknown. Therefore, this study examined the effect of household income on friendship network dynamics among classmates in a large sample of Swedish youths (n = 4787 from 235 classes, m age = 14.65, 51% girls, and 33% immigrant background), using multilevel longitudinal social network analysis. Over time, students from poorer households were less often selected as a friend by classmates and they less often initiated or maintained friendship ties than students from higher income households. Furthermore, different conceptualizations of income relative to classmates did not impact friendship formation tendencies. The findings indicate that theories of relative income do not extend understanding of students’ friendship formation beyond processes related to absolute income. In addition, this study suggests that the social integration of students from low-income households could be boosted by both promoting their agency in forming friendships and preventing exclusion by classmates.

Longitudinal Examination of Stress and Depression in Older Adults Over a 2‐Year Period: Moderation Effect of Varied Social Support Measures

Depressive symptoms and stress exposure fluctuate over time in community‐dwelling older adults, but they are frequently assessed using one‐time retrospective self‐report measures. Social support viewed as a multifaceted construct can play diverse moderating roles in this association although it is typically gauged through the measure of perceived social support. This study aims to explore the relationships between stress, social support, and depressive symptoms among older adults by utilizing the longitudinal data collected through a smartphone application and supplemented by annual face‐to‐face interviews conducted over a 2‐year period. Using longitudinal multilevel analysis, we analyzed the data on PHQ‐9, stress exposure, and four distinct measures of social support collected from 354 community‐dwelling older adults in South Korea. The results demonstrated that 59% of the variability in depressive symptoms was attributable to differences between individuals. Stress exposure was a strong predictor (γ = 3.01 ∗∗∗, 95% CI = 2.34–3.67). As expected, positive functional social support alleviated the effects of stress on depression (γ = −1.12 ∗∗, 95% CI = −1.92 ~ −0.32) while negative functional social support (γ = 2.36 ∗∗∗, 95% CI = 1.29–3.44) and negative structural social support (γ = 3.22 ∗, 95% CI = 0.79–5.64) worsened the effects of stress on depression. A notable finding is that stress‐amplifying effects from the negative functional and structural social support, in addition to well‐known stress‐buffering effects from positive functional social support, should be regarded as indispensable components in safeguarding the mental health of older adults. Considering the decline in social interactions and the lower probability of older adults establishing new social connections, it is essential to consider approaches that prevent a lack of functional and structural social support and foster a high‐quality of functional and structural social support, particularly for those facing greater stressors, as a preventative method against depressive symptoms.

The influence of adolescents' self-perception of social relationships on personality functioning in the context of inclusive education.

Adolescence is a special phase of life in which fundamentals of psychosocial functioning are formed. The present study investigates how adolescents' self-perception of social relationships in inclusive classes affect personality functioning. Furthermore, we examine whether the association between self-perceived social relationships and personality functioning is stronger for students with special educational needs in the domains of learning (SEN L) and social -emotional development (SED) than for students without SEN. At two measurement points questionnaire data was collected from 927 sixth- and seventh-graders from 20 primary and 20 comprehensive inclusive classes in Germany. Results of longitudinal multilevel analyses show partially different results for sixth- and seventh-graders. Overall, students' perceived social relatedness predicted personality functioning. Students who perceived their social relationships more positively showed healthier personality functioning. Further, SEN SED represents a potential risk factor for personality functioning. But, we observed that differences in personality functioning between seventh-graders with SEN L or SED and those without SEN decreased over time. Furthermore, SEN does not appear to reinforce the association between low self-perception of social relationships and risky personality functioning. The findings are discussed in the context of inclusive education and implications for future research as well as practice are given. Overall, our findings contribute to a better understanding of students' psychosocial development in inclusive learning environments.

Identifying individual and organizational predictors of accidental exposure to blood (AEB) among hospital healthcare workers: A longitudinal study.

Accidental exposure to blood (AEB) poses a risk of bloodborne infections for healthcare workers (HCWs) during hospital activities. In this study, we identified individual behavioral and organizational predictors of AEB among HCWs. The study was a prospective, 1-year follow-up cohort study conducted in university hospitals in Paris, France. Data were collected from the Stress at Work and Infectious Risk in Patients and Caregivers (STRIPPS) study. Eligible participants included nurses, nursing assistants, midwives, and physicians from 32 randomly selected wards in 4 hospitals. AEB occurrences were reported at baseline, 4 months, 8 months, and 12 months, and descriptive statistical and multilevel risk-factor analyses were performed. The study included 730 HCWs from 32 wards, predominantly nurses (52.6%), nursing assistants (41.1%), physicians (4.8%), and midwives (1.5%). The incidence rate of AEB remained stable across the 4 visits. The multilevel longitudinal analysis identified several significant predictors of AEB occurrence. Individual-level predictors included younger age, occupation as nurses or midwives, irregular work schedule, rotating shifts, and lack of support from supervisors. The use of external nurses was the most significant ward-level predictor associated with AEB occurrence. AEBs among HCWs are strongly associated with organizational predictors, highlighting the importance of complementing infection control policies with improved staff management and targeted training. This approach can help reduce AEB occurrences and enhance workplace safety for HCWs.

The Role of Gender Norms on Intimate Partner Violence Among Newly Married Adolescent Girls and Young Women in India: A Longitudinal Multilevel Analysis.

Gender norms have been posited to impact intimate partner violence (IPV), but there is scant evidence of the longitudinal association between community-level gender norms and IPV. Using longitudinal data on 3,965 married girls surveyed in India, we fitted mixed-effects ordinal and binary logistic regression models for physical IPV intensity and occurrence of sexual IPV. We found a 26% increase in the odds that women experience frequent physical IPV per one unit increase in greater community-level equitable gender norms. We did not find an association between community-level equitable gender norms and sexual IPV. Findings suggest that the relationship between gender norms and physical and sexual IPV differs, indicating the need for tailored interventions for different types of IPV.

Orientation towards the common good in cities: The role of individual urban mobility behavior

Orientation towards the common good is considered as a building block of social cohesion and has been shown to benefit both social communities and their residents. Mobility behavior (e.g. cycling) is associated with many positive psychological variables, but little is known about its relationship with the orientation towards the common good. This study examined the relationships between mobility behavior and four facets of orientation towards the common good: political participation, social participation in organizations, neighborhood solidarity, and neighborly helpfulness. Using a longitudinal multilevel analysis, annual surveys between 2014 and 2019 of a representative sample of the German general population (GESIS PANEL, N = 410) were analyzed. Cycling rather than driving was positively associated with orientation towards the common good in all models. Cycling was the only variable that was a significant positive predictor for all four facets of orientation towards the common good after controlling for possibly confounding variables (homeownership, personal income, education, sex). This research demonstrated that mobility behavior is associated with the orientation towards the common good. These findings are significant for policy and planning because the benefits of cycling over driving are more profound and sustainable than previously thought.

Can’t Buy Me Love (with Foreign Aid)

Abstract Does foreign aid improve the image of donors in recipient countries? Studies have found weak overall effects, but also positive correlations that are highly conditional on donor and recipient factors, like program characteristics and regime type. Our statistical and case study analysis of US foreign aid leads to a more skeptical perspective. We assess the impact of foreign aid on public opinion of the United States in twenty recipient countries during the Obama and Trump presidencies, using Pew Research Center survey data. A multi-level longitudinal analysis of individual and country-level variables finds that correlations between aid disbursements and foreign public opinion disappear when controlling for attitudes about the US president. These results are corroborated in crucial case studies of Kenya and Turkey. The findings are important for governments that use aid to influence foreign opinion and for scholarship that considers aid to be a source of soft power.