Nina Knoll

Freie Universität Berlin, Berlín, Berlin, Germany

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Publications (71)131.82 Total impact

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    ABSTRACT: Purpose: In the context of worksite influenza vaccination programmes, social support, action planning and perceived self-efficacy were examined as predictors of participation. Mechanisms among these predictors were analysed by applying the enabling effect model to vaccination. Moreover, this model was extended by the inclusion of planning. Methods: In a large German company, a survey on influenza vaccination was launched with 200 employees taking part in the five-month follow-up. Using regression procedures, a sequential mediation model was examined, leading from social support via self-efficacy and planning to vaccination behaviour. Results: The three predictors jointly accounted for 47% of the vaccination participation variance. The enabling effect model was confirmed, highlighting how social support may promote self-efficacy beliefs. Further analysis yielded the extended model, revealing planning as a mediator between self-efficacy and subsequent behaviour while the indirect path from social support via self-efficacy to behaviour remained. Conclusions: Multiple step mediation analysis underscored the relevance of social support and self-efficacy. It also revealed planning as a proximal factor that may facilitate participation in a worksite influenza vaccination programme.
    Psychology Health and Medicine 05/2014; · 1.38 Impact Factor
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    ABSTRACT: Self-efficacy, action control, and social support are considered to influence changes in physical activity levels in older adults. This study examines the relationship among these variables and explores the putative mediating and moderating mechanisms that might account for activity changes. A longitudinal study with 54 older adults (≥ 50 years of age) was carried out in Costa Rica. In a moderated mediation analysis, action control was specified as a mediator between self-efficacy and physical activity, whereas social support was specified as a moderator between self-efficacy and action control. Baseline physical activity, age, and sex were specified as covariates. Action control mediated between self-efficacy and physical activity. An interaction between social support and self-efficacy on action control pointed to a synergistic effect at the first stage of the mediating process. The effect of self-efficacy on physical activity was partly explained by action control, providing evidence of action control as a proximal mediator of physical activity. Moreover, the moderator role of social support was confirmed: high social support appeared to compensate for low levels of self-efficacy.
    Journal of Physical Activity and Health 04/2014; · 1.95 Impact Factor
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    ABSTRACT: Purpose. Motivational processes can be set in motion when positive consequences of physical exercise are experienced. However, relationships between positive exercise experience and determinants of the motivational and the volitional phases of exercise change have attracted only sparse attention in research. Method. This research examines direct and indirect associations between positive experience and motivational as well as volitional self-efficacy, intention, action planning, and exercise in two distinct longitudinal samples. The first one originates from an online observational study in the general population with three measurement points in time (N = 350) and the second one from a clinical intervention study in a rehabilitation context with four measurement points (N = 275). Results. Structural equation modeling revealed the following: Positive experience is directly related with motivational self-efficacy as well as intentions in both samples. In the online sample only, positive experience is associated with volitional self-efficacy. In each sample, experience is indirectly associated with action planning via motivational self-efficacy and intentions. Moreover, action planning, in turn, predicts changes in physical exercise levels. Conclusions. Findings suggest a more prominent role of positive experience in the motivational than in the volitional phase of physical exercise change. Thus, this research contributes to the understanding of how positive experience is involved in the behavior change process.
    Health Education &amp Behavior 04/2014; · 1.54 Impact Factor
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    ABSTRACT: The increasing prevalence of childhood overweight makes children an important target for health promotion programmes. An intervention was designed for mothers to provide more vegetables to their daughters' diet. A randomized controlled trial compared a self-regulation condition with a control condition in 155 mothers aged 25-50 years. Dependent variable was children's (aged 6-11 years) vegetable consumption which was reported by their mothers at three points in time. After baseline (Time 1), the intervention group received theory-based instructional leaflets to promote self-regulatory skills for providing a healthy nutrition for children. Changes were assessed after two weeks (Time 2) and at three-month follow-up (Time 3). The self-regulation intervention in mothers led to an increase in vegetable intake among their daughters at Time 2 but not at Time 3. However, maintenance of vegetable consumption at Time 3 was mediated by the amount of vegetable intake at Time 2. Engaging mothers in self-regulatory health promotion programmes may be a feasible strategy to facilitate more vegetable intake among their daughters.
    Psychology Health and Medicine 04/2014; · 1.38 Impact Factor
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    ABSTRACT: The dual-effects model of social control assumes that social control leads to better health practices, but also arouses psychological distress. However, findings are inconsistent. The present study advances the current literature by examining social control from a dyadic perspective in the context of smoking. In addition, the study examines whether control, continuous smoking abstinence, and affect are differentially related for men and women. Before and three weeks after a self-set quit attempt we examined 106 smokers (77 men, mean age: 40.67, average number of cigarettes smoked per day: 16.59 (SD = 8.52, range = 1-40) at baseline and 5.27 (SD = 6.97, range = 0-40) at follow-up) and their non-smoking heterosexual partners, assessing received and provided control, continuous abstinence, and affect. With regard to smoker's affective reactions, partner's provided control was related to an increase in positive and to a decrease in negative affect, but only for female smokers. Moreover, the greater the discrepancy between smoker received and partner provided control was, the more positive affect increased and the more negative affect decreased, but again only for female smokers. These findings demonstrate that female smokers' well-being was raised over time if they were not aware of the control attempts of their non-smoking partners, indicating positive effects of invisible social control. This study's results emphasize the importance of applying a dyadic perspective and taking gender differences in the dual-effects model of social control into account.
    Anxiety, stress, and coping 02/2014; · 1.55 Impact Factor
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    ABSTRACT: Objective: This study tested the applicability of the Health Action Process Approach (HAPA) in a sample of obese adults in the context of physical activity. Method: Physical activity was assessed along with motivational and volitional variables specified in the HAPA (motivational self-efficacy, outcome expectancies, risk perception, intention, maintenance self-efficacy, action planning, coping planning, recovery self-efficacy, social support) in a sample of 484 obese men and women (body mass index ≥30 kg/m2). Results: Applying structural equation modeling, the fit of the HAPA model was satisfactory-χ2(191) = 569.93, p < .05, χ2/df = 2.98, comparative fit index = .91, normed-fit index = .87, and root mean square error of approximation = .06 (90% CI = .06, .07)-explaining 30% of the variance in intention and 18% of the variance in physical activity. Motivational self-efficacy, outcome expectancies, and social support were related to intention. An association between maintenance self-efficacy and coping planning was found. Recovery self-efficacy and social support were associated with physical activity. No relationships were found between risk perception and intention and between planning and physical activity. The assumptions derived from the HAPA were partly confirmed and the HAPA may, therefore, constitute a theoretical backdrop for intervention designs to promote physical activity in adults with obesity. (PsycINFO Database Record (c) 2014 APA, all rights reserved).
    Rehabilitation Psychology 01/2014; · 1.91 Impact Factor
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    Applied Psychology Health and Well-Being 01/2014;
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    ABSTRACT: Objective Many people do not behave in line with their self-imposed goal to be more physically active. To bridge this intention-behavior gap, detailed planning is regarded as being instrumental. Moreover, preparatory actions are supposed to facilitate physical activity in conjunction with planning. Thus, preparatory actions are seen as mediators between intention and behaviors. The present study examines whether intention is translated into physical activity stepwise via planning as well as via preparatory actions. Methods At three points in time, physical activity, planning, preparatory actions, and the intention to be physically active were assessed in 338 participants. By means of structural equation modeling, it was examined whether the pathway from intention to physical activity includes a mediating sequence of planning as well as preparatory actions. Results The sequential mediation model confirmed pathways from intention to planning, from planning to preparatory behaviors, and from preparatory behaviors to follow-up physical activity, while controlling for baseline indicators. Furthermore, there was an indirect effect of intention on preparatory actions via planning, an indirect effect of planning on physical activity via preparatory actions, and an indirect effect of intention on physical activity via planning and preparatory actions thus, confirming the hypothesized sequence. Conclusions Individuals who are motivated to be physically active are likely to make a plan, and if they do so, they are more likely to take preparatory actions, resulting in a higher chance to perform the target behavior.
    Psychology of Sport and Exercise. 01/2014;
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    ABSTRACT: Background: Habit formation is thought to lead to long-term maintenance of fruit and vegetable consumption. Habits develop through context-dependent repetition, but additional variables such as intrinsic reward of behaviour may influence habit strength. Drawing upon the Associative-Cybernetic Model, this exploratory study tested different pathways by which intrinsic reward may influence fruit and vegetable consumption habit strength. Methods: In a three-wave study of fruit and vegetable intake in adults (N = 127) from the general population, intrinsic reward, intention, and self-efficacy were assessed at baseline, fruit and vegetable consumption and intrinsic reward two weeks later, and habit strength another two weeks later. Direct, indirect, and moderation effects of intrinsic reward on habit strength were tested simultaneously in a moderated mediation model. Results: Intrinsic reward had a positive indirect effect on habit strength through its influence on the frequency of fruit and vegetable consumption. Further, the relationship between fruit and vegetable consumption and habit was stronger where consumption was considered more intrinsically rewarding. Conclusions: Findings highlight the potential relevance of intrinsic reward to habit. We suggest that intrinsic rewards from behaviour may not only facilitate habit via behaviour frequency, but also reinforce the relationship between behavioural repetition and habit strength.
    Applied Psychology Health and Well-Being 11/2013; · 1.75 Impact Factor
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    ABSTRACT: A common form of social regulation of an individual's health behavior is social control. The contextual model of social control assumes that higher relationship quality goes along with more beneficial effects of social control on health behavior. This study examined potential differential moderating effects of different dimensions of relationship quality on the associations between positive and negative social control and smoking behavior and hiding smoking. The sample consisted of 144 smokers (n = 72 women; mean age = 31.78, SD = 10.04) with a nonsmoking partner. Positive and negative social control, dimensions of relationship quality consensus, cohesion and satisfaction, numbers of cigarettes smoked (NCS), hiding smoking (HS), and control variables were assessed at baseline. Four weeks later NCS and HS were assessed again. Only for smokers with high consensus, but not cohesion and satisfaction, a negative association between positive control and NCS emerged. Moreover, smokers with high consensus tended to report more HS when being positively and negatively socially controlled. This also emerged for cohesion and positive control. Satisfaction with the relationship did not display any interaction effects. This study's results emphasize the importance of differentiating not only between positive and negative social control but also between different dimensions of relationship quality in order to gain a comprehensive understanding of the dynamics in romantic dyads with regard to social regulation of behavioral change. (PsycINFO Database Record (c) 2013 APA, all rights reserved).
    Families Systems & Health 08/2013; · 1.74 Impact Factor
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    ABSTRACT: Objective : In smoking cessation, individual self-regulation and social support have both proven to be useful. However, the roles of self-regulatory processes and social support are mostly examined separately. The present study aims at examining the unique and joint interactive effects of self-regulation as specified in the health action process approach (HAPA) and social support on smoking cessation. The study tested whether social support can compensate for low levels of self-regulation or whether synergistic effects emerge. Design & Measures : Around a self-set quit date, 99 smokers completed baseline questionnaires on HAPA-variables, smoking-specific received social support and smoking cessation (continuous abstinence and point prevalence), with a follow-up Cpproximately 29 days after the quitdate. Results : Social support moderated the association between volitional self-efficacy and smoking, as well as coping planning and smoking but not between action planning and smoking. No compensatory effect of social support for lower levels of individual regulation emerged but the combination of high levels of the individual variables and social support was related to successful smoking cessation, indicating a synergistic effect. Conclusions : The results confirm the importance of examining both self-regulation and social factors in smoking cessation. This should be considered when developing future interventions for smoking cessation.
    Psychology & Health 07/2013; · 1.95 Impact Factor
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    ABSTRACT: A randomized controlled trial compared an age-tailored intervention to increase physical activity levels in older adults to an age-neutral intervention. Both interventions communicated activity planning strategies and messages to improve self-efficacy. On top of this, the age-tailored intervention also included two lifespan components that targeted present orientation and emotional focus, and fostered strategies of selection, optimization, and compensation. A total of 386 German older adults (aged 60-95 years) were randomized to receive either the age-tailored intervention (age-specific strategy training and short-term emotional focus) or the age-neutral intervention. Physical activity was measured by questionnaires at baseline (T1) and at 6-month (T2) and 12-month follow-ups (T3). Latent true change modeling was applied by creating latent change scores (T2 - T1 and T3 - T2). After controlling for gender, age, and physical and mental health, allocation to the age-tailored intervention predicted a latent physical activity difference at T3 - T2, but not at T2 - T1. Compared to the age-neutral intervention, the age-tailored intervention led to superior maintenance of physical activity within these older adults.
    International Journal of Behavioral Medicine 07/2013; · 2.63 Impact Factor
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    ABSTRACT: The study examines psychosocial mechanisms in dietary change using the health action process approach (HAPA) as its theoretical backdrop. Previous studies have supported the model in the domain of dietary behaviors but it has not yet been studied in China. Dietary planning is assumed to mediate between intentions and dietary behaviors. However, among individuals scoring low on proactive coping, this mediation might fail. Therefore, an extension of the model by including proactive coping is examined. Psychometric scales were administered at two points in time, three months apart, to 240 young Chinese men and women. Intentions, outcome expectancies, risk perception, action self-efficacy, and proactive coping were assessed at Time 1, whereas planning, coping self-efficacy, and dietary behavior were measured at Time 2. Structural equation models replicated previous evidence on the validity of the HAPA. Intentions and planning mediated sequentially the effects of outcome expectancies and self-efficacy on dietary behaviors. Moreover, the inclusion of proactive coping yielded no main effects, but an interaction between intentions and proactive coping on dietary planning. The intention - planning - behavior chain was moderated by proactive coping which means that this connection operates only well when individuals are proactive. A combination of proactive coping and the motivation to eat healthy foods facilitates dietary planning which, in turn, benefits corresponding behaviors.
    Appetite 07/2013; · 2.54 Impact Factor
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    ABSTRACT: Background: Most theories of health-behavior change focus exclusively on individual self-regulation without taking social factors, such as social support, into account. This study's first aim was to systematically test the added value of received instrumental and emotional social support within the Health Action Process Approach (HAPA) in the context of dietary change. In the social support literature, gender effects emerge with regard to the effectiveness of social support. Thus, a second aim was the examination of gender differences in the association of social support with dietary behavior. Methods: Participants were 252 overweight and obese individuals. At baseline and 12 months later, participants completed questionnaires on HAPA variables; diet-specific received social support and low-fat diet. Results: For the prediction of intentions 12 months later, instrumental support was more beneficial for men than for women over and above individual self-regulation. In terms of dietary behavior at T2, a moderate main effect of instrumental support emerged. Moreover, received emotional social support was beneficial for men, but not for women in terms of a low-fat diet 12 months later. Conclusions: Effects of received instrumental social support found in this study provide new evidence for the added value of integrating social support into the HAPA.
    Applied Psychology Health and Well-Being 04/2013; · 1.75 Impact Factor
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    ABSTRACT: When people intend and plan to perform higher levels of physical activity, they do not start on impulse without preparing. Thus, preparation is a behavioral construct positioned between planning and target behavior. This may be reflected by the acquisition of sports equipment as well as monitoring devices such as pedometers. The research questions are who takes such preparatory action, whether picking up a complimentary pedometer can be predicted by self-efficacy and outcome expectancies, and whether this kind of preparatory action facilitates subsequent physical activity. A longitudinal physical activity survey was conducted with 143 university students who were offered a complimentary pedometer. Collecting this free gift served as indicator of preparatory behavior. Outcome expectancies and self-efficacy beliefs were specified as predictors of this behavior. Two weeks later, physical activity differences between the groups were determined. Collecting the pedometer was associated with higher levels of physical activity at follow-up. Outcome expectancies failed to predict the pedometer collection, but self-efficacy did. An interaction between these two factors indicated that self-efficacy compensated for low outcome expectancies. Pedometer acquisition signifies a preparatory action that is facilitated by self-efficacy. Positioned between planning and target behavior, they constitute a proximal self-regulatory step towards health behavior change.
    Applied Psychology Health and Well-Being 03/2013; 5(1):136-47. · 1.75 Impact Factor
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    ABSTRACT: Objective : The purpose was to examine whether a 1-h intervention would help increase fruit consumption in motivated individuals and to study the role of self-regulatory mechanisms in the behaviour change process, with a particular focus on dietary planning and action control. Methods : A randomised controlled trial compared a 1-h online intervention with controls in 791 participants. Dependent variables were fruit intake, planning to consume and dietary action control. Results : Experimental condition by time interactions documented superior treatment effects for the self-regulation group, although all participants benefited from the study. To identify the contribution of the intervention ingredients, multiple mediation analyses were conducted that yielded mediator effects for dietary action control and planning. Conclusions : A very brief self-regulatory nutrition intervention was superior to a control condition. Dietary planning and action control seem to play a major role in the mechanisms that facilitate fruit intake.
    Psychology & Health 01/2013; · 1.95 Impact Factor
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    ABSTRACT: The study examined whether a dietary planning intervention would help increase fruit consumption among Iranian women focusing on self-regulatory mechanisms in behavior change. We conducted a randomized controlled trial to compare a planning intervention with a control condition in 165 Iranian women (aged 17-48years). Dependent variable was fruit intake, and dietary planning served as the mediator. After baseline assessment (T1) the intervention group received a leaflet on fruit consumption with a planning sheet. Changes were assessed at 3-weeks (T2) and at 3-months follow-ups (T3). Findings showed that the dietary planning intervention led to an increase in fruit intake. Age moderated this mediation. Changes in dietary planning mediated between intervention and fruit consumption in middle aged women. Dietary planning seems to play a role in the mechanism that facilitates fruit intake among Iranian women. This mediation by planning was found in middle aged women (30-48years old), but not in young adult women (17-29years old).
    Appetite 12/2012; · 2.54 Impact Factor
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    ABSTRACT: OBJECTIVE: This systematic review analyzed the relationships between social support and quality of life (QOL) indicators among lung cancer patients. In particular, the patterns of relationships between different social support facets and sources (received and perceived support from healthcare professionals, family, and friends) and QOL aspects (emotional, physical symptoms, functional, and social) as well as the global QOL index were investigated. METHODS: The review yielded 14 original studies (57% applying cross-sectional designs) analyzing data from a total of 2759 patients. RESULTS: Regarding healthcare professionals as support source, corroborating evidence was found for associations between received support (as well as need for and satisfaction with received support) and all aspects of QOL, except for social ones. Overall, significant relations between support from healthcare personnel and QOL were observed more frequently (67% of analyzed associations), compared with support from families and friends (53% of analyzed associations). Corroborating evidence was found for the associations between perceived and received support from family and friends and emotional aspects of QOL. Research investigating perceived social support from unspecified sources indicated few significant relationships (25% of analyzed associations) and only for the global QOL index. CONCLUSIONS: Quantitative and qualitative differences in the associations between social support and QOL are observed, depending on the source and type of support. Psychosocial interventions may aim at enabling provision of social support from healthcare personnel in order to promote emotional, functional, and physical QOL among lung cancer patients. Copyright © 2012 John Wiley & Sons, Ltd.
    Psycho-Oncology 10/2012; · 3.51 Impact Factor
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    ABSTRACT: OBJECTIVES: Experiencing positive consequences of one's physical activity is supposed to facilitate further activity. This motivational outcome might be generated by an increase in perceived self-efficacy. In addition to such a mediator effect, we examine whether this applies generally or only under conditions of volitional control. For this purpose, perceived action control was considered as a putative moderator. DESIGN AND METHOD: N = 193 students participated in a study with three measurement points in time. At baseline, positive experience with previous physical activity was measured as a predictor of physical activity. Two weeks later, self-efficacy and action control variables were assessed as putative mediator and moderator, respectively. After another 2 weeks, physical activity was measured as the outcome. A moderated mediation model was specified with baseline physical activity and sex as covariates. RESULTS: Self-efficacy was found to mediate between initial positive experience and later physical activity, and this mediation was moderated by action control. CONCLUSIONS: Participants' perceptions of positive experience were associated with their subsequent self-efficacy fostering physical activity. However, persons with low levels of action control did not translate positive experience into physical activity via self-efficacy. STATEMENT OF CONTRIBUTION: What is already known on this subject? Numerous studies have shown that exercise-specific self-efficacy predicts subsequent physical activity. Prior positive experience with physical activity is suggested to be associated with exercise-specific self-efficacy. Furthermore, action control was found to be beneficial for the maintenance of physical activity. What does this study add? This study unveils the mechanisms between these social-cognitive determinants: our longitudinal results suggest that the mediation of positive experience and subsequent physical activity via self-efficacy is moderated by action control. Persons with low levels of action control did not translate positive experience into physical activity via self-efficacy.
    British Journal of Health Psychology 09/2012; · 2.70 Impact Factor
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    ABSTRACT: Three studies tested if the associations between women's empowerment beliefs and intentions to attend cervical cancer screening could be explained by mediating psychological mechanisms: control-related beliefs, well being-related beliefs, and beliefs and evaluations referring to social functioning. Data were collected from January to March 2011 in the rural and urban areas across regions of Poland. Study 1 (N = 386) indicated that women with strong empowerment harbored stronger self-efficacy and beliefs that screening participation would make them feel in control of their own health and body. These two types of cognitions were, in turn, associated with stronger cervical cancer screening intentions. Results of Study 2 (N = 527) confirmed three significant well being-related mediators in the relationship between empowerment beliefs and cervical cancer screening: perceived benefits of screening related to well being, appearance satisfaction, discomfort- and shame-related barriers for screening. Finally, Study 3 (N = 424) showed that empowerment enabled receiving higher social support for cervical cancer screening, promoted perceiving fewer barriers for cervical cancer screening-related communication and more social benefits of engaging in cervical cancer screening. Support for cervical cancer screening, social barriers, and benefits were, in turn, related to screening intentions. Across the studies similar shares of intention variance were explained, and thus the hypothesized mediating mechanisms may have similar explanatory power.
    Women & Health 03/2012; 52(2):162-81. · 1.05 Impact Factor

Publication Stats

484 Citations
131.82 Total Impact Points


  • 2000–2014
    • Freie Universität Berlin
      • • Division of Health Psychology
      • • Institute of Psychology
      Berlín, Berlin, Germany
  • 2013
    • Universität Konstanz
      • Department of Psychology
      Constance, Baden-Württemberg, Germany
  • 2006–2013
    • University of Zurich
      • Division of Social Psychology
      Zürich, ZH, Switzerland
  • 2011–2012
    • University of Colorado Colorado Springs
      • Centre for Trauma, Health and Hazards (THHC)
      Colorado Springs, Colorado, United States
  • 2005–2012
    • Charité Universitätsmedizin Berlin
      • • Institute of Medical Psychology
      • • Medical Department, Division of Psychosomatic Medicine
      Berlin, Land Berlin, Germany
  • 2009
    • Klinikum St. Elisabeth Straubing GmbH
      Straubing, Bavaria, Germany
  • 2007
    • University of Sussex
      • School of Psychology
      Brighton, England, United Kingdom